Re: [PATCH v3] bus: mhi: core: Sanity check values from remote device before use
On 3/10/21 1:30 PM, Jeffrey Hugo wrote: When parsing the structures in the shared memory, there are values which come from the remote device. For example, a transfer completion event will have a pointer to the tre in the relevant channel's transfer ring. As another example, event ring elements may specify a channel in which the event occurred, however the specified channel value may not be valid as no channel is defined at that index even though the index may be less than the maximum allowed index. Such values should be considered to be untrusted, and validated before use. If we blindly use such values, we may access invalid data or crash if the values are corrupted. If validation fails, drop the relevant event. Signed-off-by: Jeffrey Hugo Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [RESEND PATCH] bus: mhi: core: Remove pre_init flag used for power purposes
On 4/1/21 2:41 PM, Bhaumik Bhatt wrote: Some controllers can choose to skip preparation for power up. In that case, device context is initialized based on the pre_init flag not being set during mhi_prepare_for_power_up(). There is no reason MHI host driver should maintain and provide controllers with two separate paths for preparing MHI. Going forward, all controllers will be required to call the mhi_prepare_for_power_up() API followed by their choice of sync or async power up. This allows MHI host driver to get rid of the pre_init flag and sets up a common way for all controllers to use MHI. This also helps controllers fail early on during preparation phase in some failure cases. Signed-off-by: Bhaumik Bhatt --- This patch was tested on arm64 architecture. Change looks good as current MHI controllers ath11k and pci generic are not using pre_init. Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v2 RESEND] bus: mhi: core: Wait for ready state after reset
On 3/10/21 12:41 PM, Jeffrey Hugo wrote: After the device has signaled the end of reset by clearing the reset bit, it will automatically reinit MHI and the internal device structures. Once That is done, the device will signal it has entered the ready state. Signaling the ready state involves sending an interrupt (MSI) to the host which might cause IOMMU faults if it occurs at the wrong time. If the controller is being powered down, and possibly removed, then the reset flow would only wait for the end of reset. At which point, the host and device would start a race. The host may complete its reset work, and remove the interrupt handler, which would cause the interrupt to be disabled in the IOMMU. If that occurs before the device signals the ready state, then the IOMMU will fault since it blocked an interrupt. While harmless, the fault would appear like a serious issue has occurred so let's silence it by making sure the device hits the ready state before the host completes its reset processing. Signed-off-by: Jeffrey Hugo Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v6 1/4] bus: mhi: core: Destroy SBL devices when moving to mission mode
On 2/24/21 3:23 PM, Bhaumik Bhatt wrote: Currently, client devices are created in SBL or AMSS (mission mode) and only destroyed after power down or SYS ERROR. When moving between certain execution environments, such as from SBL to AMSS, no clean-up is required. This presents an issue where SBL-specific channels are left open and client drivers now run in an execution environment where they cannot operate. Fix this by expanding the mhi_destroy_device() to do an execution environment specific clean-up if one is requested. Close the gap and destroy devices in such scenarios that allow SBL client drivers to clean up once device enters mission mode. Signed-off-by: Bhaumik Bhatt It make sense to clean up previous execution env related resources. Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v3] bus: mhi: core: Return EAGAIN if MHI ring is full
On 2/17/21 8:26 AM, Jeffrey Hugo wrote: From: Fan Wu Currently ENOMEM is returned when MHI ring is full. This error code is very misleading. Change to EAGAIN instead. Signed-off-by: Fan Wu Signed-off-by: Jeffrey Hugo --- Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v6 8/8] bus: mhi: core: Do not clear channel context more than once
On 2/4/21 12:28 PM, Bhaumik Bhatt wrote: Clearing a channel context can happen twice if the client driver unprepares and reset the channels from the remove() callback from a controller requested MHI power down sequence. If there are multiple attempts at calling the mhi_free_coherent() API, we see kernel warnings such as "trying to free invalid coherent area". Example for one such client is the QRTR MHI driver. Avoid these warnings by skipping mhi_deinit_chan_ctxt() API call and prevent extra work from MHI as the channels are already disabled. Signed-off-by: Bhaumik Bhatt Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v2 3/3] bus: mhi: core: Process execution environment changes serially
On 1/14/21 11:16 AM, Bhaumik Bhatt wrote: In current design, whenever the BHI interrupt is fired, the execution environment is updated. This can cause race conditions and impede any ongoing power up/down processing. For example, if a power down is in progress and the host has updated the execution environment to a local "disabled" state, any BHI interrupt firing later could replace it with the value from the BHI EE register. Can we add what is the real issue observed when mhi_cntrl->ee changed in above scenario? Another example would be that the device can enter mission mode while device creation for SBL is still going on, leading to multiple attempts at opening the same channel. Even for this scenario, can we add the real issue that was observed e.g. same device was attempting to get created twice and caused xyz issue? Ensure that EE changes are handled only from appropriate places and occur one after another and handle only PBL or RDDM EE changes as critical events directly from the interrupt handler. This also makes sure that we use the correct execution environment to notify the controller driver when the device resets to one of the PBL execution environments. [..] Thanks, Hemant -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v2 2/3] bus: mhi: core: Download AMSS image from appropriate function
Hi Bhaumik, On 1/14/21 11:16 AM, Bhaumik Bhatt wrote: During full boot chain firmware download, the PM state worker downloads the AMSS image after waiting for the SBL execution environment change in PBL mode itself. Since getting rid of the firmware load worker thread, this design needs to change and MHI Can we reword this as current driver does not have firmware load worker thread. Basically change is to avoid blocking st worker thread with a timeout to get SBL EE before starting AMSS image download. Instead trigger AMSS image download directly from the st worker thread when DEV_ST_TRANSITION_SBL is queued. host must download the AMSS image from the SBL mode of PM state worker thread instead. Since the full boot chain firmware download is associated with a synchronous power up and has MHI host waiting for a transition to mission mode with a timeout, we can skip creating any devices (or probing any client drivers) in SBL mode transition and proceed directly with the AMSS image download. This means that if MHI host driver is not responsible for the AMSS image download or the controller plans to have client drivers opening any SBL channels, for example, to download images or monitor debug logs for memory allocations or power management, the device can be powered up asynchronously. [..] Thanks, Hemant -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v2 1/3] bus: mhi: core: Clear devices when moving execution environments
On 1/14/21 11:16 AM, Bhaumik Bhatt wrote: When moving from SBL to mission mode execution environment, there is no remove callback notification to MHI client drivers which operate on SBL mode only. Client driver devices are being created in SBL or AMSS(mission mode) and only destroyed after power down or SYS_ERROR. If there exist any SBL-specific channels, those are left open and client drivers are thus unaware of the new execution environment where those channels cannot operate. Close the gap and issue remove callbacks to SBL-specific client drivers once device enters mission mode. Signed-off-by: Bhaumik Bhatt Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v5 9/9] bus: mhi: core: Do not clear channel context more than once
On 1/8/21 12:54 PM, Bhaumik Bhatt wrote: When clearing the channel context, calling mhi_free_coherent() more than once can result in kernel warnings such as "trying to free invalid coherent area". Prevent extra work by adding a check to skip calling mhi_deinit_chan_ctxt() if the client driver has already disabled the channels. Signed-off-by: Bhaumik Bhatt --- drivers/bus/mhi/core/init.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c index 30eef19..272f350 100644 --- a/drivers/bus/mhi/core/init.c +++ b/drivers/bus/mhi/core/init.c @@ -1314,6 +1314,7 @@ static int mhi_driver_remove(struct device *dev) if ((ch_state[dir] == MHI_CH_STATE_ENABLED || ch_state[dir] == MHI_CH_STATE_STOP) && + mhi_chan->ch_state != MHI_CH_STATE_DISABLED && !mhi_chan->offload_ch) mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan); Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[RESEND PATCH v18 3/3] bus: mhi: Add userspace client interface driver
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
/dev/
This interface allows exposing modem control channel(s) such as QMI, MBIM,
or AT commands to userspace which can be used to configure the modem using
tools such as libqmi, ModemManager, minicom (for AT), etc over MHI. This is
required as there are no kernel APIs to access modem control path for device
configuration. Data path transporting the network payload (IP), however, is
routed to the Linux network via the mhi-net driver. Currently driver supports
QMI channel. libqmi is userspace MHI client which communicates to a QMI
service using QMI channel. Please refer to
https://www.freedesktop.org/wiki/Software/libqmi/ for additional information
on libqmi.
Signed-off-by: Hemant Kumar
Reviewed-by: Manivannan Sadhasivam
Reviewed-by: Jeffrey Hugo
Tested-by: Loic Poulain
---
drivers/bus/mhi/Kconfig | 13 +
drivers/bus/mhi/Makefile | 3 +
drivers/bus/mhi/uci.c| 664 +++
3 files changed, 680 insertions(+)
create mode 100644 drivers/bus/mhi/uci.c
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index da5cd0c..5194e8e 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -29,3 +29,16 @@ config MHI_BUS_PCI_GENERIC
This driver provides MHI PCI controller driver for devices such as
Qualcomm SDX55 based PCIe modems.
+config MHI_UCI
+ tristate "MHI UCI"
+ depends on MHI_BUS
+ help
+ MHI based Userspace Client Interface (UCI) driver is used for
+ transferring raw data between host and device using standard file
+ operations from userspace. Open, read, write, poll and close
+ operations are supported by this driver. Please check
+ mhi_uci_match_table for all supported channels that are exposed to
+ userspace.
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_uci.
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 0a2d778..69f2111 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -4,3 +4,6 @@ obj-y += core/
obj-$(CONFIG_MHI_BUS_PCI_GENERIC) += mhi_pci_generic.o
mhi_pci_generic-y += pci_generic.o
+# MHI client
+mhi_uci-y := uci.o
+obj-$(CONFIG_MHI_UCI) += mhi_uci.o
diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c
new file mode 100644
index 000..1df2377
--- /dev/null
+++ b/drivers/bus/mhi/uci.c
@@ -0,0 +1,664 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/
+
+#include
+#include
+#include
+#include
+#include
+
+#define MHI_UCI_DRIVER_NAME "mhi_uci"
+#define MHI_MAX_UCI_MINORS 128
+
+static DEFINE_IDR(uci_idr);
+static DEFINE_MUTEX(uci_drv_mutex);
+static struct class *uci_dev_class;
+static int uci_dev_major;
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_pending_lock: spin lock for dl_pending list
+ * @dl_pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
+
+/**
+ * struct uci_buf - UCI buffer
+ * @data: data buffer
+ * @len: length of data buffer
+ * @node: list node of the UCI buffer
+ */
+struct uci_buf {
+ void *data;
+ size_t len;
+ struct list_head node;
+};
+
+/**
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Fla
[RESEND PATCH v18 2/3] docs: Add documentation for userspace client interface
MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently QMI MHI channel is supported by this driver. Signed-off-by: Hemant Kumar Reviewed-by: Jeffrey Hugo --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 95 + 2 files changed, 96 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..1e0a015 --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,95 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + +UCI driver enables userspace clients to communicate to external MHI devices +like modem. UCI driver probe creates standard character device file nodes for +userspace clients to perform open, read, write, poll and release file +operations. UCI device object represents UCI device file node which gets +instantiated as part of MHI UCI driver probe. UCI channel object represents +MHI uplink or downlink channel. + +Operations +== + +open + + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read + + +When data transfer is completed on downlink channel, transfer ring element +buffer is copied to pending list. Reader is unblocked and data is copied to +userspace buffer. Transfer ring element buffer is queued back to downlink +channel transfer ring. + +write +- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll + + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. When the uplink channel transfer ring is non-empty, more +data may be sent to the device. Returns EPOLLERR when UCI driver is removed. + +release +--- + +Decrements UCI device reference count and UCI channel reference count. Upon +last release() UCI channel clean up is performed. MHI channel moves to disable +state and inbound buffers are freed. + +Usage += + +Device file node is created with format:- + +/dev/ + +mhi_device_name includes mhi controller name and the name of the MHI channel +being used by MHI client in userspace to send or receive data using MHI +protocol. + +There is a separate character device file node created for each channel +specified in MHI device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +Qualcomm MSM Interface(QMI) Channel +--- + +Qualcomm MSM Interface(QMI) is a modem control messaging protocol used to +communicate between software components in the modem and other peripheral +subsystems. QMI communication is of request/response type or an unsolicited +event type. libqmi is userspace MHI client which communicates to a QMI service +using UCI device. It sends a QMI request to a QMI service using MHI channel 14 +or 16. QMI response is received using MHI channel 15 or 17 respectively. libqmi +is a glib-based library for talking to WWAN modems and devices which speaks QMI +protocol. For more information about libqmi please refer +https://www.freedesktop.org/wiki/Software/libqmi/ + +Usage Example +~ + +QMI command to retrieve device mode +$ sudo qmicli -d /dev/mhi0_QMI --dms-get-model +[/dev/mhi0_QMI] Device model retrieved: +Model: 'FN980m' + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diagnostic +client using DIAG channel 4 (Host to device) and 5 (Device to Host). -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[RESEND PATCH v18 1/3] bus: mhi: core: Move MHI_MAX_MTU to external header file
Currently this macro is defined in internal MHI header as
a TRE length mask. Moving it to external header allows MHI
client drivers to set this upper bound for the transmit
buffer size.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/internal.h | 1 -
include/linux/mhi.h | 3 +++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 6f80ec3..2b9c063 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -453,7 +453,6 @@ enum mhi_pm_state {
#define CMD_EL_PER_RING128
#define PRIMARY_CMD_RING 0
#define MHI_DEV_WAKE_DB127
-#define MHI_MAX_MTU0x
#define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1)
enum mhi_er_type {
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index e36d575..f072605 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -15,6 +15,9 @@
#include
#include
+/* MHI client drivers to set this upper bound for tx buffer */
+#define MHI_MAX_MTU 0x
+
#define MHI_MAX_OEM_PK_HASH_SEGMENTS 16
struct mhi_chan;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[RESEND PATCH v18 0/3] userspace MHI client interface driver
ation describing uci client driver use cases. - Fixed uci ref counting in mhi_uci_open for error case. - Addressed style related review comments. V3: Added documentation for MHI UCI driver. V2: - Added mutex lock to prevent multiple readers to access same - mhi buffer which can result into use after free. Hemant Kumar (3): bus: mhi: core: Move MHI_MAX_MTU to external header file docs: Add documentation for userspace client interface bus: mhi: Add userspace client interface driver Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 95 ++ drivers/bus/mhi/Kconfig | 13 + drivers/bus/mhi/Makefile| 3 + drivers/bus/mhi/core/internal.h | 1 - drivers/bus/mhi/uci.c | 664 include/linux/mhi.h | 3 + 7 files changed, 779 insertions(+), 1 deletion(-) create mode 100644 Documentation/mhi/uci.rst create mode 100644 drivers/bus/mhi/uci.c -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v18 0/3] userspace MHI client interface driver
ation describing uci client driver use cases. - Fixed uci ref counting in mhi_uci_open for error case. - Addressed style related review comments. V3: Added documentation for MHI UCI driver. V2: - Added mutex lock to prevent multiple readers to access same - mhi buffer which can result into use after free. Hemant Kumar (3): bus: mhi: core: Move MHI_MAX_MTU to external header file docs: Add documentation for userspace client interface bus: mhi: Add userspace client interface driver Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 95 ++ drivers/bus/mhi/Kconfig | 13 + drivers/bus/mhi/Makefile| 3 + drivers/bus/mhi/core/internal.h | 1 - drivers/bus/mhi/uci.c | 664 include/linux/mhi.h | 3 + 7 files changed, 779 insertions(+), 1 deletion(-) create mode 100644 Documentation/mhi/uci.rst create mode 100644 drivers/bus/mhi/uci.c -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v18 1/3] bus: mhi: core: Move MHI_MAX_MTU to external header file
Currently this macro is defined in internal MHI header as
a TRE length mask. Moving it to external header allows MHI
client drivers to set this upper bound for the transmit
buffer size.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/internal.h | 1 -
include/linux/mhi.h | 3 +++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 6f80ec3..2b9c063 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -453,7 +453,6 @@ enum mhi_pm_state {
#define CMD_EL_PER_RING128
#define PRIMARY_CMD_RING 0
#define MHI_DEV_WAKE_DB127
-#define MHI_MAX_MTU0x
#define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1)
enum mhi_er_type {
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index e36d575..f072605 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -15,6 +15,9 @@
#include
#include
+/* MHI client drivers to set this upper bound for tx buffer */
+#define MHI_MAX_MTU 0x
+
#define MHI_MAX_OEM_PK_HASH_SEGMENTS 16
struct mhi_chan;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v18 2/3] docs: Add documentation for userspace client interface
MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently QMI MHI channel is supported by this driver. Signed-off-by: Hemant Kumar Reviewed-by: Jeffrey Hugo --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 95 + 2 files changed, 96 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..1e0a015 --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,95 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + +UCI driver enables userspace clients to communicate to external MHI devices +like modem. UCI driver probe creates standard character device file nodes for +userspace clients to perform open, read, write, poll and release file +operations. UCI device object represents UCI device file node which gets +instantiated as part of MHI UCI driver probe. UCI channel object represents +MHI uplink or downlink channel. + +Operations +== + +open + + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read + + +When data transfer is completed on downlink channel, transfer ring element +buffer is copied to pending list. Reader is unblocked and data is copied to +userspace buffer. Transfer ring element buffer is queued back to downlink +channel transfer ring. + +write +- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll + + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. When the uplink channel transfer ring is non-empty, more +data may be sent to the device. Returns EPOLLERR when UCI driver is removed. + +release +--- + +Decrements UCI device reference count and UCI channel reference count. Upon +last release() UCI channel clean up is performed. MHI channel moves to disable +state and inbound buffers are freed. + +Usage += + +Device file node is created with format:- + +/dev/ + +mhi_device_name includes mhi controller name and the name of the MHI channel +being used by MHI client in userspace to send or receive data using MHI +protocol. + +There is a separate character device file node created for each channel +specified in MHI device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +Qualcomm MSM Interface(QMI) Channel +--- + +Qualcomm MSM Interface(QMI) is a modem control messaging protocol used to +communicate between software components in the modem and other peripheral +subsystems. QMI communication is of request/response type or an unsolicited +event type. libqmi is userspace MHI client which communicates to a QMI service +using UCI device. It sends a QMI request to a QMI service using MHI channel 14 +or 16. QMI response is received using MHI channel 15 or 17 respectively. libqmi +is a glib-based library for talking to WWAN modems and devices which speaks QMI +protocol. For more information about libqmi please refer +https://www.freedesktop.org/wiki/Software/libqmi/ + +Usage Example +~ + +QMI command to retrieve device mode +$ sudo qmicli -d /dev/mhi0_QMI --dms-get-model +[/dev/mhi0_QMI] Device model retrieved: +Model: 'FN980m' + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diagnostic +client using DIAG channel 4 (Host to device) and 5 (Device to Host). -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v18 3/3] bus: mhi: Add userspace client interface driver
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
/dev/
This interface allows exposing modem control channel(s) such as QMI, MBIM,
or AT commands to userspace which can be used to configure the modem using
tools such as libqmi, ModemManager, minicom (for AT), etc over MHI. This is
required as there are no kernel APIs to access modem control path for device
configuration. Data path transporting the network payload (IP), however, is
routed to the Linux network via the mhi-net driver. Currently driver supports
QMI channel. libqmi is userspace MHI client which communicates to a QMI
service using QMI channel. Please refer to
https://www.freedesktop.org/wiki/Software/libqmi/ for additional information
on libqmi.
Signed-off-by: Hemant Kumar
Reviewed-by: Manivannan Sadhasivam
Reviewed-by: Jeffrey Hugo
Tested-by: Loic Poulain
---
drivers/bus/mhi/Kconfig | 13 +
drivers/bus/mhi/Makefile | 3 +
drivers/bus/mhi/uci.c| 664 +++
3 files changed, 680 insertions(+)
create mode 100644 drivers/bus/mhi/uci.c
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index da5cd0c..5194e8e 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -29,3 +29,16 @@ config MHI_BUS_PCI_GENERIC
This driver provides MHI PCI controller driver for devices such as
Qualcomm SDX55 based PCIe modems.
+config MHI_UCI
+ tristate "MHI UCI"
+ depends on MHI_BUS
+ help
+ MHI based Userspace Client Interface (UCI) driver is used for
+ transferring raw data between host and device using standard file
+ operations from userspace. Open, read, write, poll and close
+ operations are supported by this driver. Please check
+ mhi_uci_match_table for all supported channels that are exposed to
+ userspace.
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_uci.
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 0a2d778..69f2111 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -4,3 +4,6 @@ obj-y += core/
obj-$(CONFIG_MHI_BUS_PCI_GENERIC) += mhi_pci_generic.o
mhi_pci_generic-y += pci_generic.o
+# MHI client
+mhi_uci-y := uci.o
+obj-$(CONFIG_MHI_UCI) += mhi_uci.o
diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c
new file mode 100644
index 000..1df2377
--- /dev/null
+++ b/drivers/bus/mhi/uci.c
@@ -0,0 +1,664 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/
+
+#include
+#include
+#include
+#include
+#include
+
+#define MHI_UCI_DRIVER_NAME "mhi_uci"
+#define MHI_MAX_UCI_MINORS 128
+
+static DEFINE_IDR(uci_idr);
+static DEFINE_MUTEX(uci_drv_mutex);
+static struct class *uci_dev_class;
+static int uci_dev_major;
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_pending_lock: spin lock for dl_pending list
+ * @dl_pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
+
+/**
+ * struct uci_buf - UCI buffer
+ * @data: data buffer
+ * @len: length of data buffer
+ * @node: list node of the UCI buffer
+ */
+struct uci_buf {
+ void *data;
+ size_t len;
+ struct list_head node;
+};
+
+/**
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Fla
[PATCH v17 0/3] userspace MHI client interface driver
This patch series adds support for UCI driver. UCI driver enables userspace clients to communicate to external MHI devices like modem. UCI driver probe creates standard character device file nodes for userspace clients to perform open, read, write, poll and release file operations. These file operations call MHI core layer APIs to perform data transfer using MHI bus to communicate with MHI device. Currently driver supports QMI channel. libqmi is userspace MHI client which communicates to a QMI service using QMI channel. libqmi is a glib-based library for talking to WWAN modems and devices which speaks QMI protocol. For more information about libqmi please refer https://www.freedesktop.org/wiki/Software/libqmi/. Patch is tested using arm64 and x86 based platform. v17: - Updated commit text for UCI driver by mentioning about libqmi open-source userspace program that will be talking to this UCI kernel driver. - UCI driver depends upon patch "bus: mhi: core: Add helper API to return number of free TREs". v16: - Removed reference of WLAN as an external MHI device in documentation and cover letter. v15: - Updated documentation related to poll and release operations. V14: - Fixed device file node format to /dev/ instead of /dev/mhi_ because "mhi" is already part of mhi device name. For example old format: /dev/mhi_mhi0_QMI new format: /dev/mhi0_QMI. - Updated MHI documentation to reflect index mhi controller name in QMI usage example. V13: - Removed LOOPBACK channel from mhi_device_id table from this patch series. Pushing a new patch series to add support for LOOPBACK channel and the user space test application. Also removed the description from kernel documentation. - Added QMI channel to mhi_device_id table. QMI channel has existing libqmi support from user space. - Updated kernel Documentation for QMI channel and provided external reference for libqmi. - Updated device file node name by appending mhi device name only, which already includes mhi controller device name. V12: - Added loopback test driver under selftest/drivers/mhi. Updated kernel documentation for the usage of the loopback test application. - Addressed review comments for renaming variable names, updated inline comments and removed two redundant dev_dbg. V11: - Fixed review comments for UCI documentation by expanding TLAs and rewording some sentences. V10: - Replaced mutex_lock with mutex_lock_interruptible in read() and write() file ops call back. V9: - Renamed dl_lock to dl_pending _lock and pending list to dl_pending for clarity. - Used read lock to protect cur_buf. - Change transfer status check logic and only consider 0 and -EOVERFLOW as only success. - Added __int to module init function. - Print channel name instead of minor number upon successful probe. V8: - Fixed kernel test robot compilation error by changing %lu to %zu for size_t. - Replaced uci with UCI in Kconfig, commit text, and comments in driver code. - Fixed minor style related comments. V7: - Decoupled uci device and uci channel objects. uci device is associated with device file node. uci channel is associated with MHI channels. uci device refers to uci channel to perform MHI channel operations for device file operations like read() and write(). uci device increments its reference count for every open(). uci device calls mhi_uci_dev_start_chan() to start the MHI channel. uci channel object is tracking number of times MHI channel is referred. This allows to keep the MHI channel in start state until last release() is called. After that uci channel reference count goes to 0 and uci channel clean up is performed which stops the MHI channel. After the last call to release() if driver is removed uci reference count becomes 0 and uci object is cleaned up. - Use separate uci channel read and write lock to fine grain locking between reader and writer. - Use uci device lock to synchronize open, release and driver remove. - Optimize for downlink only or uplink only UCI device. V6: - Moved uci.c to mhi directory. - Updated Kconfig to add module information. - Updated Makefile to rename uci object file name as mhi_uci - Removed kref for open count V5: - Removed mhi_uci_drv structure. - Used idr instead of creating global list of uci devices. - Used kref instead of local ref counting for uci device and open count. - Removed unlikely macro. V4: - Fix locking to protect proper struct members. - Updated documentation describing uci client driver use cases. - Fixed uci ref counting in mhi_uci_open for error case. - Addressed style related review comments. V3: Added documentation for MHI UCI driver. V2: - Added mutex lock to prevent multiple readers to access same - mhi buffer which can result into use after free. Hemant Kumar (3): bus: mhi: core: Move MHI_MAX_MTU to external header file docs: Add documentation for userspace client interface bus: mhi: Add userspace client interface dr
[PATCH v17 1/3] bus: mhi: core: Move MHI_MAX_MTU to external header file
Currently this macro is defined in internal MHI header as
a TRE length mask. Moving it to external header allows MHI
client drivers to set this upper bound for the transmit
buffer size.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/internal.h | 1 -
include/linux/mhi.h | 3 +++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 6f80ec3..2b9c063 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -453,7 +453,6 @@ enum mhi_pm_state {
#define CMD_EL_PER_RING128
#define PRIMARY_CMD_RING 0
#define MHI_DEV_WAKE_DB127
-#define MHI_MAX_MTU0x
#define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1)
enum mhi_er_type {
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index e36d575..f072605 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -15,6 +15,9 @@
#include
#include
+/* MHI client drivers to set this upper bound for tx buffer */
+#define MHI_MAX_MTU 0x
+
#define MHI_MAX_OEM_PK_HASH_SEGMENTS 16
struct mhi_chan;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v17 2/3] docs: Add documentation for userspace client interface
MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently QMI MHI channel is supported by this driver. Signed-off-by: Hemant Kumar Reviewed-by: Jeffrey Hugo --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 95 + 2 files changed, 96 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..1e0a015 --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,95 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + +UCI driver enables userspace clients to communicate to external MHI devices +like modem. UCI driver probe creates standard character device file nodes for +userspace clients to perform open, read, write, poll and release file +operations. UCI device object represents UCI device file node which gets +instantiated as part of MHI UCI driver probe. UCI channel object represents +MHI uplink or downlink channel. + +Operations +== + +open + + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read + + +When data transfer is completed on downlink channel, transfer ring element +buffer is copied to pending list. Reader is unblocked and data is copied to +userspace buffer. Transfer ring element buffer is queued back to downlink +channel transfer ring. + +write +- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll + + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. When the uplink channel transfer ring is non-empty, more +data may be sent to the device. Returns EPOLLERR when UCI driver is removed. + +release +--- + +Decrements UCI device reference count and UCI channel reference count. Upon +last release() UCI channel clean up is performed. MHI channel moves to disable +state and inbound buffers are freed. + +Usage += + +Device file node is created with format:- + +/dev/ + +mhi_device_name includes mhi controller name and the name of the MHI channel +being used by MHI client in userspace to send or receive data using MHI +protocol. + +There is a separate character device file node created for each channel +specified in MHI device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +Qualcomm MSM Interface(QMI) Channel +--- + +Qualcomm MSM Interface(QMI) is a modem control messaging protocol used to +communicate between software components in the modem and other peripheral +subsystems. QMI communication is of request/response type or an unsolicited +event type. libqmi is userspace MHI client which communicates to a QMI service +using UCI device. It sends a QMI request to a QMI service using MHI channel 14 +or 16. QMI response is received using MHI channel 15 or 17 respectively. libqmi +is a glib-based library for talking to WWAN modems and devices which speaks QMI +protocol. For more information about libqmi please refer +https://www.freedesktop.org/wiki/Software/libqmi/ + +Usage Example +~ + +QMI command to retrieve device mode +$ sudo qmicli -d /dev/mhi0_QMI --dms-get-model +[/dev/mhi0_QMI] Device model retrieved: +Model: 'FN980m' + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diagnostic +client using DIAG channel 4 (Host to device) and 5 (Device to Host). -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v17 3/3] bus: mhi: Add userspace client interface driver
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
/dev/
Currently it supports QMI channel. libqmi is userspace MHI client which
communicates to a QMI service using QMI channel. libqmi is a glib-based
library for talking to WWAN modems and devices which speaks QMI protocol.
For more information about libqmi please refer
https://www.freedesktop.org/wiki/Software/libqmi/
Signed-off-by: Hemant Kumar
Reviewed-by: Manivannan Sadhasivam
Reviewed-by: Jeffrey Hugo
Tested-by: Loic Poulain
---
drivers/bus/mhi/Kconfig | 13 +
drivers/bus/mhi/Makefile | 3 +
drivers/bus/mhi/uci.c| 664 +++
3 files changed, 680 insertions(+)
create mode 100644 drivers/bus/mhi/uci.c
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index da5cd0c..5194e8e 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -29,3 +29,16 @@ config MHI_BUS_PCI_GENERIC
This driver provides MHI PCI controller driver for devices such as
Qualcomm SDX55 based PCIe modems.
+config MHI_UCI
+ tristate "MHI UCI"
+ depends on MHI_BUS
+ help
+ MHI based Userspace Client Interface (UCI) driver is used for
+ transferring raw data between host and device using standard file
+ operations from userspace. Open, read, write, poll and close
+ operations are supported by this driver. Please check
+ mhi_uci_match_table for all supported channels that are exposed to
+ userspace.
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_uci.
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 0a2d778..69f2111 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -4,3 +4,6 @@ obj-y += core/
obj-$(CONFIG_MHI_BUS_PCI_GENERIC) += mhi_pci_generic.o
mhi_pci_generic-y += pci_generic.o
+# MHI client
+mhi_uci-y := uci.o
+obj-$(CONFIG_MHI_UCI) += mhi_uci.o
diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c
new file mode 100644
index 000..1df2377
--- /dev/null
+++ b/drivers/bus/mhi/uci.c
@@ -0,0 +1,664 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/
+
+#include
+#include
+#include
+#include
+#include
+
+#define MHI_UCI_DRIVER_NAME "mhi_uci"
+#define MHI_MAX_UCI_MINORS 128
+
+static DEFINE_IDR(uci_idr);
+static DEFINE_MUTEX(uci_drv_mutex);
+static struct class *uci_dev_class;
+static int uci_dev_major;
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_pending_lock: spin lock for dl_pending list
+ * @dl_pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
+
+/**
+ * struct uci_buf - UCI buffer
+ * @data: data buffer
+ * @len: length of data buffer
+ * @node: list node of the UCI buffer
+ */
+struct uci_buf {
+ void *data;
+ size_t len;
+ struct list_head node;
+};
+
+/**
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Flag to track the state of the UCI device
+ * @lock: mutex lock to manage uchan object
+ * @ref_count: uci_dev reference count
+ */
+struct uci_dev {
+ unsigned int minor;
+ struct mhi_device *mhi_dev;
+ struct uci_chan *uchan;
+ size_t mtu;
+ bool enabled;
+
+ /* synchronize open, release and driver remove */
+
[PATCH v16 0/4] userspace MHI client interface driver
This patch series adds support for UCI driver. UCI driver enables userspace clients to communicate to external MHI devices like modem. UCI driver probe creates standard character device file nodes for userspace clients to perform open, read, write, poll and release file operations. These file operations call MHI core layer APIs to perform data transfer using MHI bus to communicate with MHI device. Patch is tested using arm64 and x86 based platform. v16: - Removed reference of WLAN as an external MHI device in documentation and cover letter. v15: - Updated documentation related to poll and release operations. V14: - Fixed device file node format to /dev/ instead of /dev/mhi_ because "mhi" is already part of mhi device name. For example old format: /dev/mhi_mhi0_QMI new format: /dev/mhi0_QMI. - Updated MHI documentation to reflect index mhi controller name in QMI usage example. V13: - Removed LOOPBACK channel from mhi_device_id table from this patch series. Pushing a new patch series to add support for LOOPBACK channel and the user space test application. Also removed the description from kernel documentation. - Added QMI channel to mhi_device_id table. QMI channel has existing libqmi support from user space. - Updated kernel Documentation for QMI channel and provided external reference for libqmi. - Updated device file node name by appending mhi device name only, which already includes mhi controller device name. V12: - Added loopback test driver under selftest/drivers/mhi. Updated kernel documentation for the usage of the loopback test application. - Addressed review comments for renaming variable names, updated inline comments and removed two redundant dev_dbg. V11: - Fixed review comments for UCI documentation by expanding TLAs and rewording some sentences. V10: - Replaced mutex_lock with mutex_lock_interruptible in read() and write() file ops call back. V9: - Renamed dl_lock to dl_pending _lock and pending list to dl_pending for clarity. - Used read lock to protect cur_buf. - Change transfer status check logic and only consider 0 and -EOVERFLOW as only success. - Added __int to module init function. - Print channel name instead of minor number upon successful probe. V8: - Fixed kernel test robot compilation error by changing %lu to %zu for size_t. - Replaced uci with UCI in Kconfig, commit text, and comments in driver code. - Fixed minor style related comments. V7: - Decoupled uci device and uci channel objects. uci device is associated with device file node. uci channel is associated with MHI channels. uci device refers to uci channel to perform MHI channel operations for device file operations like read() and write(). uci device increments its reference count for every open(). uci device calls mhi_uci_dev_start_chan() to start the MHI channel. uci channel object is tracking number of times MHI channel is referred. This allows to keep the MHI channel in start state until last release() is called. After that uci channel reference count goes to 0 and uci channel clean up is performed which stops the MHI channel. After the last call to release() if driver is removed uci reference count becomes 0 and uci object is cleaned up. - Use separate uci channel read and write lock to fine grain locking between reader and writer. - Use uci device lock to synchronize open, release and driver remove. - Optimize for downlink only or uplink only UCI device. V6: - Moved uci.c to mhi directory. - Updated Kconfig to add module information. - Updated Makefile to rename uci object file name as mhi_uci - Removed kref for open count V5: - Removed mhi_uci_drv structure. - Used idr instead of creating global list of uci devices. - Used kref instead of local ref counting for uci device and open count. - Removed unlikely macro. V4: - Fix locking to protect proper struct members. - Updated documentation describing uci client driver use cases. - Fixed uci ref counting in mhi_uci_open for error case. - Addressed style related review comments. V3: Added documentation for MHI UCI driver. V2: - Added mutex lock to prevent multiple readers to access same - mhi buffer which can result into use after free. Hemant Kumar (4): bus: mhi: core: Add helper API to return number of free TREs bus: mhi: core: Move MHI_MAX_MTU to external header file docs: Add documentation for userspace client interface bus: mhi: Add userspace client interface driver Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 95 ++ drivers/bus/mhi/Kconfig | 13 + drivers/bus/mhi/Makefile| 3 + drivers/bus/mhi/core/internal.h | 1 - drivers/bus/mhi/core/main.c | 12 + drivers/bus/mhi/uci.c | 664 include/linux/mhi.h | 12 + 8 files changed, 800 insertions(+), 1 deletion(-) create mode 100644 Documentation/mhi/uci.rst create mode 100644 drivers/bus
[PATCH v16 3/4] docs: Add documentation for userspace client interface
MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently QMI MHI channel is supported by this driver. Signed-off-by: Hemant Kumar Reviewed-by: Jeffrey Hugo --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 95 + 2 files changed, 96 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..1e0a015 --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,95 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + +UCI driver enables userspace clients to communicate to external MHI devices +like modem. UCI driver probe creates standard character device file nodes for +userspace clients to perform open, read, write, poll and release file +operations. UCI device object represents UCI device file node which gets +instantiated as part of MHI UCI driver probe. UCI channel object represents +MHI uplink or downlink channel. + +Operations +== + +open + + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read + + +When data transfer is completed on downlink channel, transfer ring element +buffer is copied to pending list. Reader is unblocked and data is copied to +userspace buffer. Transfer ring element buffer is queued back to downlink +channel transfer ring. + +write +- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll + + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. When the uplink channel transfer ring is non-empty, more +data may be sent to the device. Returns EPOLLERR when UCI driver is removed. + +release +--- + +Decrements UCI device reference count and UCI channel reference count. Upon +last release() UCI channel clean up is performed. MHI channel moves to disable +state and inbound buffers are freed. + +Usage += + +Device file node is created with format:- + +/dev/ + +mhi_device_name includes mhi controller name and the name of the MHI channel +being used by MHI client in userspace to send or receive data using MHI +protocol. + +There is a separate character device file node created for each channel +specified in MHI device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +Qualcomm MSM Interface(QMI) Channel +--- + +Qualcomm MSM Interface(QMI) is a modem control messaging protocol used to +communicate between software components in the modem and other peripheral +subsystems. QMI communication is of request/response type or an unsolicited +event type. libqmi is userspace MHI client which communicates to a QMI service +using UCI device. It sends a QMI request to a QMI service using MHI channel 14 +or 16. QMI response is received using MHI channel 15 or 17 respectively. libqmi +is a glib-based library for talking to WWAN modems and devices which speaks QMI +protocol. For more information about libqmi please refer +https://www.freedesktop.org/wiki/Software/libqmi/ + +Usage Example +~ + +QMI command to retrieve device mode +$ sudo qmicli -d /dev/mhi0_QMI --dms-get-model +[/dev/mhi0_QMI] Device model retrieved: +Model: 'FN980m' + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diagnostic +client using DIAG channel 4 (Host to device) and 5 (Device to Host). -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v16 4/4] bus: mhi: Add userspace client interface driver
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
/dev/
Currently it supports QMI channel.
Signed-off-by: Hemant Kumar
Reviewed-by: Manivannan Sadhasivam
Reviewed-by: Jeffrey Hugo
Tested-by: Loic Poulain
---
drivers/bus/mhi/Kconfig | 13 +
drivers/bus/mhi/Makefile | 3 +
drivers/bus/mhi/uci.c| 664 +++
3 files changed, 680 insertions(+)
create mode 100644 drivers/bus/mhi/uci.c
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index da5cd0c..5194e8e 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -29,3 +29,16 @@ config MHI_BUS_PCI_GENERIC
This driver provides MHI PCI controller driver for devices such as
Qualcomm SDX55 based PCIe modems.
+config MHI_UCI
+ tristate "MHI UCI"
+ depends on MHI_BUS
+ help
+ MHI based Userspace Client Interface (UCI) driver is used for
+ transferring raw data between host and device using standard file
+ operations from userspace. Open, read, write, poll and close
+ operations are supported by this driver. Please check
+ mhi_uci_match_table for all supported channels that are exposed to
+ userspace.
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_uci.
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 0a2d778..69f2111 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -4,3 +4,6 @@ obj-y += core/
obj-$(CONFIG_MHI_BUS_PCI_GENERIC) += mhi_pci_generic.o
mhi_pci_generic-y += pci_generic.o
+# MHI client
+mhi_uci-y := uci.o
+obj-$(CONFIG_MHI_UCI) += mhi_uci.o
diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c
new file mode 100644
index 000..1df2377
--- /dev/null
+++ b/drivers/bus/mhi/uci.c
@@ -0,0 +1,664 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/
+
+#include
+#include
+#include
+#include
+#include
+
+#define MHI_UCI_DRIVER_NAME "mhi_uci"
+#define MHI_MAX_UCI_MINORS 128
+
+static DEFINE_IDR(uci_idr);
+static DEFINE_MUTEX(uci_drv_mutex);
+static struct class *uci_dev_class;
+static int uci_dev_major;
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_pending_lock: spin lock for dl_pending list
+ * @dl_pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
+
+/**
+ * struct uci_buf - UCI buffer
+ * @data: data buffer
+ * @len: length of data buffer
+ * @node: list node of the UCI buffer
+ */
+struct uci_buf {
+ void *data;
+ size_t len;
+ struct list_head node;
+};
+
+/**
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Flag to track the state of the UCI device
+ * @lock: mutex lock to manage uchan object
+ * @ref_count: uci_dev reference count
+ */
+struct uci_dev {
+ unsigned int minor;
+ struct mhi_device *mhi_dev;
+ struct uci_chan *uchan;
+ size_t mtu;
+ bool enabled;
+
+ /* synchronize open, release and driver remove */
+ struct mutex lock;
+ struct kref ref_count;
+};
+
+static void mhi_uci_dev_chan_release(struct kref *ref)
+{
+ struct uci_buf *buf_itr, *tmp;
+ struct uci_chan *uchan =
+ container_of(ref, struct uci_chan, ref_count);
+
+ if (
[PATCH v16 1/4] bus: mhi: core: Add helper API to return number of free TREs
Introduce mhi_get_free_desc_count() API to return number
of TREs available to queue buffer. MHI clients can use this
API to know before hand if ring is full without calling queue
API.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/main.c | 12
include/linux/mhi.h | 9 +
2 files changed, 21 insertions(+)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 702c31b..74a25e7 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -260,6 +260,18 @@ int mhi_destroy_device(struct device *dev, void *data)
return 0;
}
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ struct mhi_chan *mhi_chan = (dir == DMA_TO_DEVICE) ?
+ mhi_dev->ul_chan : mhi_dev->dl_chan;
+ struct mhi_ring *tre_ring = _chan->tre_ring;
+
+ return get_nr_avail_ring_elements(mhi_cntrl, tre_ring);
+}
+EXPORT_SYMBOL_GPL(mhi_get_free_desc_count);
+
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
{
struct mhi_driver *mhi_drv;
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index aa9757e..e36d575 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -599,6 +599,15 @@ void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl,
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason);
/**
+ * mhi_get_free_desc_count - Get transfer ring length
+ * Get # of TD available to queue buffers
+ * @mhi_dev: Device associated with the channels
+ * @dir: Direction of the channel
+ */
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir);
+
+/**
* mhi_prepare_for_power_up - Do pre-initialization before power up.
*This is optional, call this before power up if
*the controller does not want bus framework to
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v16 2/4] bus: mhi: core: Move MHI_MAX_MTU to external header file
Currently this macro is defined in internal MHI header as
a TRE length mask. Moving it to external header allows MHI
client drivers to set this upper bound for the transmit
buffer size.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/internal.h | 1 -
include/linux/mhi.h | 3 +++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 6f80ec3..2b9c063 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -453,7 +453,6 @@ enum mhi_pm_state {
#define CMD_EL_PER_RING128
#define PRIMARY_CMD_RING 0
#define MHI_DEV_WAKE_DB127
-#define MHI_MAX_MTU0x
#define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1)
enum mhi_er_type {
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index e36d575..f072605 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -15,6 +15,9 @@
#include
#include
+/* MHI client drivers to set this upper bound for tx buffer */
+#define MHI_MAX_MTU 0x
+
#define MHI_MAX_OEM_PK_HASH_SEGMENTS 16
struct mhi_chan;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Re: [PATCH] mhi: use irq_flags if client driver configures it
On 12/7/20 7:55 PM, Carl Huang wrote:
If client driver has specified the irq_flags, mhi uses this specified
irq_flags. Otherwise, mhi uses default irq_flags.
The purpose of this change is to support one MSI vector for QCA6390.
MHI will use one same MSI vector too in this scenario.
In case of one MSI vector, IRQ_NO_BALANCING is needed when irq handler
is requested. The reason is if irq migration happens, the msi_data may
change too. However, the msi_data is already programmed to QCA6390
hardware during initialization phase. This msi_data inconsistence will
result in crash in kernel.
Another issue is in case of one MSI vector, IRQF_NO_SUSPEND will trigger
WARNINGS because QCA6390 wants to disable the IRQ during the suspend.
To avoid above two issues, QCA6390 driver specifies the irq_flags in case
of one MSI vector when mhi_register_controller is called.
Signed-off-by: Carl Huang
---
drivers/bus/mhi/core/init.c | 9 +++--
include/linux/mhi.h | 1 +
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 0ffdebd..5f74e1e 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -148,12 +148,17 @@ int mhi_init_irq_setup(struct mhi_controller *mhi_cntrl)
{
struct mhi_event *mhi_event = mhi_cntrl->mhi_event;
struct device *dev = _cntrl->mhi_dev->dev;
+ unsigned long irq_flags = IRQF_SHARED | IRQF_NO_SUSPEND;
int i, ret;
+ /* if client driver has set irq_flags, use it */
+ if (mhi_cntrl->irq_flags)
+ irq_flags = mhi_cntrl->irq_flags;
Jeff if i remember correctly your use case also have one dedicated irq
line for all the MSIs, just want to confirm if you are fine with this
change ? i was wondering if any input check is required for irq_flags
passed by controller, or responsibility is on controller for any
undesired behavior. Like passing IRQF_SHARED and IRQF_ONESHOT when one
irq line is shared among multiple MSIs.
+
/* Setup BHI_INTVEC IRQ */
ret = request_threaded_irq(mhi_cntrl->irq[0], mhi_intvec_handler,
mhi_intvec_threaded_handler,
- IRQF_SHARED | IRQF_NO_SUSPEND,
+ irq_flags,
"bhi", mhi_cntrl);
if (ret)
return ret;
@@ -171,7 +176,7 @@ int mhi_init_irq_setup(struct mhi_controller *mhi_cntrl)
ret = request_irq(mhi_cntrl->irq[mhi_event->irq],
mhi_irq_handler,
- IRQF_SHARED | IRQF_NO_SUSPEND,
+ irq_flags,
"mhi", mhi_event);
if (ret) {
dev_err(dev, "Error requesting irq:%d for ev:%d\n",
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index d4841e5..f039e58 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -442,6 +442,7 @@ struct mhi_controller {
bool fbc_download;
bool pre_init;
bool wake_set;
+ unsigned long irq_flags;
};
/**
Thanks,
Hemant
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Re: [PATCH v4 5/8] bus: mhi: core: Add support to stop or start channel data transfers
On 12/3/20 5:23 PM, Bhaumik Bhatt wrote: Some MHI client drivers may want to request a pause or halt of data transfer activity on their channels. Support for this does not exist and must be introduced, wherein the channel context is not reset or cleared but only the STOP channel command is issued. This would need to be paired with an API that allows resuming the data transfer activity on channels by use of the START channel command. Enable this using two new APIs, mhi_start_transfer() and mhi_stop_transfer(). Signed-off-by: Bhaumik Bhatt Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v4 4/8] bus: mhi: core: Clear configuration from channel context during reset
On 12/3/20 5:23 PM, Bhaumik Bhatt wrote: When clearing up the channel context after client drivers are done using channels, the configuration is currently not being reset entirely. Ensure this is done to appropriately handle issues where clients unaware of the context state end up calling functions which expect a context. Signed-off-by: Bhaumik Bhatt --- Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v4 1/8] bus: mhi: core: Allow sending the STOP channel command
On 12/3/20 5:23 PM, Bhaumik Bhatt wrote: Add support to allow sending the STOP channel command. If a client driver would like to STOP a channel and have the device retain the channel context instead of issuing a RESET to it and clearing the context, this would provide support for it after the ability to send this command is exposed to clients. Signed-off-by: Bhaumik Bhatt --- Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[RESEND v15 4/4] bus: mhi: Add userspace client interface driver
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
/dev/
Currently it supports QMI channel.
Signed-off-by: Hemant Kumar
Reviewed-by: Manivannan Sadhasivam
Reviewed-by: Jeffrey Hugo
Tested-by: Loic Poulain
---
drivers/bus/mhi/Kconfig | 13 +
drivers/bus/mhi/Makefile | 3 +
drivers/bus/mhi/uci.c| 664 +++
3 files changed, 680 insertions(+)
create mode 100644 drivers/bus/mhi/uci.c
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index da5cd0c..5194e8e 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -29,3 +29,16 @@ config MHI_BUS_PCI_GENERIC
This driver provides MHI PCI controller driver for devices such as
Qualcomm SDX55 based PCIe modems.
+config MHI_UCI
+ tristate "MHI UCI"
+ depends on MHI_BUS
+ help
+ MHI based Userspace Client Interface (UCI) driver is used for
+ transferring raw data between host and device using standard file
+ operations from userspace. Open, read, write, poll and close
+ operations are supported by this driver. Please check
+ mhi_uci_match_table for all supported channels that are exposed to
+ userspace.
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_uci.
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 0a2d778..69f2111 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -4,3 +4,6 @@ obj-y += core/
obj-$(CONFIG_MHI_BUS_PCI_GENERIC) += mhi_pci_generic.o
mhi_pci_generic-y += pci_generic.o
+# MHI client
+mhi_uci-y := uci.o
+obj-$(CONFIG_MHI_UCI) += mhi_uci.o
diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c
new file mode 100644
index 000..1df2377
--- /dev/null
+++ b/drivers/bus/mhi/uci.c
@@ -0,0 +1,664 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/
+
+#include
+#include
+#include
+#include
+#include
+
+#define MHI_UCI_DRIVER_NAME "mhi_uci"
+#define MHI_MAX_UCI_MINORS 128
+
+static DEFINE_IDR(uci_idr);
+static DEFINE_MUTEX(uci_drv_mutex);
+static struct class *uci_dev_class;
+static int uci_dev_major;
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_pending_lock: spin lock for dl_pending list
+ * @dl_pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
+
+/**
+ * struct uci_buf - UCI buffer
+ * @data: data buffer
+ * @len: length of data buffer
+ * @node: list node of the UCI buffer
+ */
+struct uci_buf {
+ void *data;
+ size_t len;
+ struct list_head node;
+};
+
+/**
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Flag to track the state of the UCI device
+ * @lock: mutex lock to manage uchan object
+ * @ref_count: uci_dev reference count
+ */
+struct uci_dev {
+ unsigned int minor;
+ struct mhi_device *mhi_dev;
+ struct uci_chan *uchan;
+ size_t mtu;
+ bool enabled;
+
+ /* synchronize open, release and driver remove */
+ struct mutex lock;
+ struct kref ref_count;
+};
+
+static void mhi_uci_dev_chan_release(struct kref *ref)
+{
+ struct uci_buf *buf_itr, *tmp;
+ struct uci_chan *uchan =
+ container_of(ref, struct uci_chan, ref_count);
+
+ if (
[RESEND v15 2/4] bus: mhi: core: Move MHI_MAX_MTU to external header file
Currently this macro is defined in internal MHI header as
a TRE length mask. Moving it to external header allows MHI
client drivers to set this upper bound for the transmit
buffer size.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/internal.h | 1 -
include/linux/mhi.h | 3 +++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 6f80ec3..2b9c063 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -453,7 +453,6 @@ enum mhi_pm_state {
#define CMD_EL_PER_RING128
#define PRIMARY_CMD_RING 0
#define MHI_DEV_WAKE_DB127
-#define MHI_MAX_MTU0x
#define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1)
enum mhi_er_type {
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index e36d575..f072605 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -15,6 +15,9 @@
#include
#include
+/* MHI client drivers to set this upper bound for tx buffer */
+#define MHI_MAX_MTU 0x
+
#define MHI_MAX_OEM_PK_HASH_SEGMENTS 16
struct mhi_chan;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[RESEND v15 3/4] docs: Add documentation for userspace client interface
MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently QMI MHI channel is supported by this driver. Signed-off-by: Hemant Kumar Reviewed-by: Jeffrey Hugo --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 95 + 2 files changed, 96 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..df1f0c4 --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,95 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + +UCI driver enables userspace clients to communicate to external MHI devices +like modem and WLAN. UCI driver probe creates standard character device file +nodes for userspace clients to perform open, read, write, poll and release file +operations. UCI device object represents UCI device file node which gets +instantiated as part of MHI UCI driver probe. UCI channel object represents +MHI uplink or downlink channel. + +Operations +== + +open + + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read + + +When data transfer is completed on downlink channel, transfer ring element +buffer is copied to pending list. Reader is unblocked and data is copied to +userspace buffer. Transfer ring element buffer is queued back to downlink +channel transfer ring. + +write +- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll + + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. When the uplink channel transfer ring is non-empty, more +data may be sent to the device. Returns EPOLLERR when UCI driver is removed. + +release +--- + +Decrements UCI device reference count and UCI channel reference count. Upon +last release() UCI channel clean up is performed. MHI channel moves to disable +state and inbound buffers are freed. + +Usage += + +Device file node is created with format:- + +/dev/ + +mhi_device_name includes mhi controller name and the name of the MHI channel +being used by MHI client in userspace to send or receive data using MHI +protocol. + +There is a separate character device file node created for each channel +specified in MHI device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +Qualcomm MSM Interface(QMI) Channel +--- + +Qualcomm MSM Interface(QMI) is a modem control messaging protocol used to +communicate between software components in the modem and other peripheral +subsystems. QMI communication is of request/response type or an unsolicited +event type. libqmi is userspace MHI client which communicates to a QMI service +using UCI device. It sends a QMI request to a QMI service using MHI channel 14 +or 16. QMI response is received using MHI channel 15 or 17 respectively. libqmi +is a glib-based library for talking to WWAN modems and devices which speaks QMI +protocol. For more information about libqmi please refer +https://www.freedesktop.org/wiki/Software/libqmi/ + +Usage Example +~ + +QMI command to retrieve device mode +$ sudo qmicli -d /dev/mhi0_QMI --dms-get-model +[/dev/mhi0_QMI] Device model retrieved: +Model: 'FN980m' + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diagnostic +client using DIAG channel 4 (Host to device) and 5 (Device to Host). -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[RESEND v15 1/4] bus: mhi: core: Add helper API to return number of free TREs
Introduce mhi_get_free_desc_count() API to return number
of TREs available to queue buffer. MHI clients can use this
API to know before hand if ring is full without calling queue
API.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/main.c | 12
include/linux/mhi.h | 9 +
2 files changed, 21 insertions(+)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 702c31b..74a25e7 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -260,6 +260,18 @@ int mhi_destroy_device(struct device *dev, void *data)
return 0;
}
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ struct mhi_chan *mhi_chan = (dir == DMA_TO_DEVICE) ?
+ mhi_dev->ul_chan : mhi_dev->dl_chan;
+ struct mhi_ring *tre_ring = _chan->tre_ring;
+
+ return get_nr_avail_ring_elements(mhi_cntrl, tre_ring);
+}
+EXPORT_SYMBOL_GPL(mhi_get_free_desc_count);
+
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
{
struct mhi_driver *mhi_drv;
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index aa9757e..e36d575 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -599,6 +599,15 @@ void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl,
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason);
/**
+ * mhi_get_free_desc_count - Get transfer ring length
+ * Get # of TD available to queue buffers
+ * @mhi_dev: Device associated with the channels
+ * @dir: Direction of the channel
+ */
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir);
+
+/**
* mhi_prepare_for_power_up - Do pre-initialization before power up.
*This is optional, call this before power up if
*the controller does not want bus framework to
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[RESEND v15 0/4] userspace MHI client interface driver
This patch series adds support for UCI driver. UCI driver enables userspace clients to communicate to external MHI devices like modem and WLAN. UCI driver probe creates standard character device file nodes for userspace clients to perform open, read, write, poll and release file operations. These file operations call MHI core layer APIs to perform data transfer using MHI bus to communicate with MHI device. Patch is tested using arm64 and x86 based platform. v15: - Updated documentation related to poll and release operations. V14: - Fixed device file node format to /dev/ instead of /dev/mhi_ because "mhi" is already part of mhi device name. For example old format: /dev/mhi_mhi0_QMI new format: /dev/mhi0_QMI. - Updated MHI documentation to reflect index mhi controller name in QMI usage example. V13: - Removed LOOPBACK channel from mhi_device_id table from this patch series. Pushing a new patch series to add support for LOOPBACK channel and the user space test application. Also removed the description from kernel documentation. - Added QMI channel to mhi_device_id table. QMI channel has existing libqmi support from user space. - Updated kernel Documentation for QMI channel and provided external reference for libqmi. - Updated device file node name by appending mhi device name only, which already includes mhi controller device name. V12: - Added loopback test driver under selftest/drivers/mhi. Updated kernel documentation for the usage of the loopback test application. - Addressed review comments for renaming variable names, updated inline comments and removed two redundant dev_dbg. V11: - Fixed review comments for UCI documentation by expanding TLAs and rewording some sentences. V10: - Replaced mutex_lock with mutex_lock_interruptible in read() and write() file ops call back. V9: - Renamed dl_lock to dl_pending _lock and pending list to dl_pending for clarity. - Used read lock to protect cur_buf. - Change transfer status check logic and only consider 0 and -EOVERFLOW as only success. - Added __int to module init function. - Print channel name instead of minor number upon successful probe. V8: - Fixed kernel test robot compilation error by changing %lu to %zu for size_t. - Replaced uci with UCI in Kconfig, commit text, and comments in driver code. - Fixed minor style related comments. V7: - Decoupled uci device and uci channel objects. uci device is associated with device file node. uci channel is associated with MHI channels. uci device refers to uci channel to perform MHI channel operations for device file operations like read() and write(). uci device increments its reference count for every open(). uci device calls mhi_uci_dev_start_chan() to start the MHI channel. uci channel object is tracking number of times MHI channel is referred. This allows to keep the MHI channel in start state until last release() is called. After that uci channel reference count goes to 0 and uci channel clean up is performed which stops the MHI channel. After the last call to release() if driver is removed uci reference count becomes 0 and uci object is cleaned up. - Use separate uci channel read and write lock to fine grain locking between reader and writer. - Use uci device lock to synchronize open, release and driver remove. - Optimize for downlink only or uplink only UCI device. V6: - Moved uci.c to mhi directory. - Updated Kconfig to add module information. - Updated Makefile to rename uci object file name as mhi_uci - Removed kref for open count V5: - Removed mhi_uci_drv structure. - Used idr instead of creating global list of uci devices. - Used kref instead of local ref counting for uci device and open count. - Removed unlikely macro. V4: - Fix locking to protect proper struct members. - Updated documentation describing uci client driver use cases. - Fixed uci ref counting in mhi_uci_open for error case. - Addressed style related review comments. V3: Added documentation for MHI UCI driver. V2: - Added mutex lock to prevent multiple readers to access same - mhi buffer which can result into use after free. Hemant Kumar (4): bus: mhi: core: Add helper API to return number of free TREs bus: mhi: core: Move MHI_MAX_MTU to external header file docs: Add documentation for userspace client interface bus: mhi: Add userspace client interface driver Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 95 ++ drivers/bus/mhi/Kconfig | 13 + drivers/bus/mhi/Makefile| 3 + drivers/bus/mhi/core/internal.h | 1 - drivers/bus/mhi/core/main.c | 12 + drivers/bus/mhi/uci.c | 664 include/linux/mhi.h | 12 + 8 files changed, 800 insertions(+), 1 deletion(-) create mode 100644 Documentation/mhi/uci.rst create mode 100644 drivers/bus/mhi/uci.c -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux
Re: [PATCH v15 4/4] bus: mhi: Add userspace client interface driver
On 12/3/20 3:45 PM, Jeffrey Hugo wrote: On 12/3/2020 3:45 PM, Hemant Kumar wrote: This MHI client driver allows userspace clients to transfer raw data between MHI device and host using standard file operations. Driver instantiates UCI device object which is associated to device file node. UCI device object instantiates UCI channel object when device file node is opened. UCI channel object is used to manage MHI channels by calling MHI core APIs for read and write operations. MHI channels are started as part of device open(). MHI channels remain in start state until last release() is called on UCI device file node. Device file node is created with format /dev/ Currently it supports QMI channel. Signed-off-by: Hemant Kumar Reviewed-by: Manivannan Sadhasivam Reviewed-by: Jeffrey Hugo You dropped Loic's tested by. Was that a mistake, or did something actually change which would invalidate his testing? Thanks for pointing this out, it was my bad. Re-sending the patch. -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v15 3/4] docs: Add documentation for userspace client interface
MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently QMI MHI channel is supported by this driver. Signed-off-by: Hemant Kumar Reviewed-by: Jeffrey Hugo --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 95 + 2 files changed, 96 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..df1f0c4 --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,95 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + +UCI driver enables userspace clients to communicate to external MHI devices +like modem and WLAN. UCI driver probe creates standard character device file +nodes for userspace clients to perform open, read, write, poll and release file +operations. UCI device object represents UCI device file node which gets +instantiated as part of MHI UCI driver probe. UCI channel object represents +MHI uplink or downlink channel. + +Operations +== + +open + + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read + + +When data transfer is completed on downlink channel, transfer ring element +buffer is copied to pending list. Reader is unblocked and data is copied to +userspace buffer. Transfer ring element buffer is queued back to downlink +channel transfer ring. + +write +- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll + + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. When the uplink channel transfer ring is non-empty, more +data may be sent to the device. Returns EPOLLERR when UCI driver is removed. + +release +--- + +Decrements UCI device reference count and UCI channel reference count. Upon +last release() UCI channel clean up is performed. MHI channel moves to disable +state and inbound buffers are freed. + +Usage += + +Device file node is created with format:- + +/dev/ + +mhi_device_name includes mhi controller name and the name of the MHI channel +being used by MHI client in userspace to send or receive data using MHI +protocol. + +There is a separate character device file node created for each channel +specified in MHI device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +Qualcomm MSM Interface(QMI) Channel +--- + +Qualcomm MSM Interface(QMI) is a modem control messaging protocol used to +communicate between software components in the modem and other peripheral +subsystems. QMI communication is of request/response type or an unsolicited +event type. libqmi is userspace MHI client which communicates to a QMI service +using UCI device. It sends a QMI request to a QMI service using MHI channel 14 +or 16. QMI response is received using MHI channel 15 or 17 respectively. libqmi +is a glib-based library for talking to WWAN modems and devices which speaks QMI +protocol. For more information about libqmi please refer +https://www.freedesktop.org/wiki/Software/libqmi/ + +Usage Example +~ + +QMI command to retrieve device mode +$ sudo qmicli -d /dev/mhi0_QMI --dms-get-model +[/dev/mhi0_QMI] Device model retrieved: +Model: 'FN980m' + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diagnostic +client using DIAG channel 4 (Host to device) and 5 (Device to Host). -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v15 1/4] bus: mhi: core: Add helper API to return number of free TREs
Introduce mhi_get_free_desc_count() API to return number
of TREs available to queue buffer. MHI clients can use this
API to know before hand if ring is full without calling queue
API.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/main.c | 12
include/linux/mhi.h | 9 +
2 files changed, 21 insertions(+)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 702c31b..74a25e7 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -260,6 +260,18 @@ int mhi_destroy_device(struct device *dev, void *data)
return 0;
}
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ struct mhi_chan *mhi_chan = (dir == DMA_TO_DEVICE) ?
+ mhi_dev->ul_chan : mhi_dev->dl_chan;
+ struct mhi_ring *tre_ring = _chan->tre_ring;
+
+ return get_nr_avail_ring_elements(mhi_cntrl, tre_ring);
+}
+EXPORT_SYMBOL_GPL(mhi_get_free_desc_count);
+
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
{
struct mhi_driver *mhi_drv;
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index aa9757e..e36d575 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -599,6 +599,15 @@ void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl,
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason);
/**
+ * mhi_get_free_desc_count - Get transfer ring length
+ * Get # of TD available to queue buffers
+ * @mhi_dev: Device associated with the channels
+ * @dir: Direction of the channel
+ */
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir);
+
+/**
* mhi_prepare_for_power_up - Do pre-initialization before power up.
*This is optional, call this before power up if
*the controller does not want bus framework to
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v15 2/4] bus: mhi: core: Move MHI_MAX_MTU to external header file
Currently this macro is defined in internal MHI header as
a TRE length mask. Moving it to external header allows MHI
client drivers to set this upper bound for the transmit
buffer size.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/internal.h | 1 -
include/linux/mhi.h | 3 +++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 6f80ec3..2b9c063 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -453,7 +453,6 @@ enum mhi_pm_state {
#define CMD_EL_PER_RING128
#define PRIMARY_CMD_RING 0
#define MHI_DEV_WAKE_DB127
-#define MHI_MAX_MTU0x
#define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1)
enum mhi_er_type {
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index e36d575..f072605 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -15,6 +15,9 @@
#include
#include
+/* MHI client drivers to set this upper bound for tx buffer */
+#define MHI_MAX_MTU 0x
+
#define MHI_MAX_OEM_PK_HASH_SEGMENTS 16
struct mhi_chan;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v15 4/4] bus: mhi: Add userspace client interface driver
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
/dev/
Currently it supports QMI channel.
Signed-off-by: Hemant Kumar
Reviewed-by: Manivannan Sadhasivam
Reviewed-by: Jeffrey Hugo
---
drivers/bus/mhi/Kconfig | 13 +
drivers/bus/mhi/Makefile | 3 +
drivers/bus/mhi/uci.c| 664 +++
3 files changed, 680 insertions(+)
create mode 100644 drivers/bus/mhi/uci.c
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index da5cd0c..5194e8e 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -29,3 +29,16 @@ config MHI_BUS_PCI_GENERIC
This driver provides MHI PCI controller driver for devices such as
Qualcomm SDX55 based PCIe modems.
+config MHI_UCI
+ tristate "MHI UCI"
+ depends on MHI_BUS
+ help
+ MHI based Userspace Client Interface (UCI) driver is used for
+ transferring raw data between host and device using standard file
+ operations from userspace. Open, read, write, poll and close
+ operations are supported by this driver. Please check
+ mhi_uci_match_table for all supported channels that are exposed to
+ userspace.
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_uci.
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 0a2d778..69f2111 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -4,3 +4,6 @@ obj-y += core/
obj-$(CONFIG_MHI_BUS_PCI_GENERIC) += mhi_pci_generic.o
mhi_pci_generic-y += pci_generic.o
+# MHI client
+mhi_uci-y := uci.o
+obj-$(CONFIG_MHI_UCI) += mhi_uci.o
diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c
new file mode 100644
index 000..1df2377
--- /dev/null
+++ b/drivers/bus/mhi/uci.c
@@ -0,0 +1,664 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/
+
+#include
+#include
+#include
+#include
+#include
+
+#define MHI_UCI_DRIVER_NAME "mhi_uci"
+#define MHI_MAX_UCI_MINORS 128
+
+static DEFINE_IDR(uci_idr);
+static DEFINE_MUTEX(uci_drv_mutex);
+static struct class *uci_dev_class;
+static int uci_dev_major;
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_pending_lock: spin lock for dl_pending list
+ * @dl_pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
+
+/**
+ * struct uci_buf - UCI buffer
+ * @data: data buffer
+ * @len: length of data buffer
+ * @node: list node of the UCI buffer
+ */
+struct uci_buf {
+ void *data;
+ size_t len;
+ struct list_head node;
+};
+
+/**
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Flag to track the state of the UCI device
+ * @lock: mutex lock to manage uchan object
+ * @ref_count: uci_dev reference count
+ */
+struct uci_dev {
+ unsigned int minor;
+ struct mhi_device *mhi_dev;
+ struct uci_chan *uchan;
+ size_t mtu;
+ bool enabled;
+
+ /* synchronize open, release and driver remove */
+ struct mutex lock;
+ struct kref ref_count;
+};
+
+static void mhi_uci_dev_chan_release(struct kref *ref)
+{
+ struct uci_buf *buf_itr, *tmp;
+ struct uci_chan *uchan =
+ container_of(ref, struct uci_chan, ref_count);
+
+ if (
[PATCH v15 0/4] userspace MHI client interface driver
This patch series adds support for UCI driver. UCI driver enables userspace clients to communicate to external MHI devices like modem and WLAN. UCI driver probe creates standard character device file nodes for userspace clients to perform open, read, write, poll and release file operations. These file operations call MHI core layer APIs to perform data transfer using MHI bus to communicate with MHI device. Patch is tested using arm64 and x86 based platform. v15: - Updated documentation related to poll and release operations. V14: - Fixed device file node format to /dev/ instead of /dev/mhi_ because "mhi" is already part of mhi device name. For example old format: /dev/mhi_mhi0_QMI new format: /dev/mhi0_QMI. - Updated MHI documentation to reflect index mhi controller name in QMI usage example. V13: - Removed LOOPBACK channel from mhi_device_id table from this patch series. Pushing a new patch series to add support for LOOPBACK channel and the user space test application. Also removed the description from kernel documentation. - Added QMI channel to mhi_device_id table. QMI channel has existing libqmi support from user space. - Updated kernel Documentation for QMI channel and provided external reference for libqmi. - Updated device file node name by appending mhi device name only, which already includes mhi controller device name. V12: - Added loopback test driver under selftest/drivers/mhi. Updated kernel documentation for the usage of the loopback test application. - Addressed review comments for renaming variable names, updated inline comments and removed two redundant dev_dbg. V11: - Fixed review comments for UCI documentation by expanding TLAs and rewording some sentences. V10: - Replaced mutex_lock with mutex_lock_interruptible in read() and write() file ops call back. V9: - Renamed dl_lock to dl_pending _lock and pending list to dl_pending for clarity. - Used read lock to protect cur_buf. - Change transfer status check logic and only consider 0 and -EOVERFLOW as only success. - Added __int to module init function. - Print channel name instead of minor number upon successful probe. V8: - Fixed kernel test robot compilation error by changing %lu to %zu for size_t. - Replaced uci with UCI in Kconfig, commit text, and comments in driver code. - Fixed minor style related comments. V7: - Decoupled uci device and uci channel objects. uci device is associated with device file node. uci channel is associated with MHI channels. uci device refers to uci channel to perform MHI channel operations for device file operations like read() and write(). uci device increments its reference count for every open(). uci device calls mhi_uci_dev_start_chan() to start the MHI channel. uci channel object is tracking number of times MHI channel is referred. This allows to keep the MHI channel in start state until last release() is called. After that uci channel reference count goes to 0 and uci channel clean up is performed which stops the MHI channel. After the last call to release() if driver is removed uci reference count becomes 0 and uci object is cleaned up. - Use separate uci channel read and write lock to fine grain locking between reader and writer. - Use uci device lock to synchronize open, release and driver remove. - Optimize for downlink only or uplink only UCI device. V6: - Moved uci.c to mhi directory. - Updated Kconfig to add module information. - Updated Makefile to rename uci object file name as mhi_uci - Removed kref for open count V5: - Removed mhi_uci_drv structure. - Used idr instead of creating global list of uci devices. - Used kref instead of local ref counting for uci device and open count. - Removed unlikely macro. V4: - Fix locking to protect proper struct members. - Updated documentation describing uci client driver use cases. - Fixed uci ref counting in mhi_uci_open for error case. - Addressed style related review comments. V3: Added documentation for MHI UCI driver. V2: - Added mutex lock to prevent multiple readers to access same - mhi buffer which can result into use after free. Hemant Kumar (4): bus: mhi: core: Add helper API to return number of free TREs bus: mhi: core: Move MHI_MAX_MTU to external header file docs: Add documentation for userspace client interface bus: mhi: Add userspace client interface driver Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 95 ++ drivers/bus/mhi/Kconfig | 13 + drivers/bus/mhi/Makefile| 3 + drivers/bus/mhi/core/internal.h | 1 - drivers/bus/mhi/core/main.c | 12 + drivers/bus/mhi/uci.c | 664 include/linux/mhi.h | 12 + 8 files changed, 800 insertions(+), 1 deletion(-) create mode 100644 Documentation/mhi/uci.rst create mode 100644 drivers/bus/mhi/uci.c -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux
Re: [PATCH v14 3/4] docs: Add documentation for userspace client interface
Hi Jeff On 12/3/20 12:38 PM, jh...@codeaurora.org wrote: On 2020-12-01 19:59, Hemant Kumar wrote: MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently QMI MHI channel is supported by this driver. Signed-off-by: Hemant Kumar Two minor nits below. With those - Reviewed-by: Jeffrey Hugo --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 94 + 2 files changed, 95 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..9603f92 --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,94 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + +UCI driver enables userspace clients to communicate to external MHI devices +like modem and WLAN. UCI driver probe creates standard character device file +nodes for userspace clients to perform open, read, write, poll and release file +operations. UCI device object represents UCI device file node which gets +instantiated as part of MHI UCI driver probe. UCI channel object represents +MHI uplink or downlink channel. + +Operations +== + +open + + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read + + +When data transfer is completed on downlink channel, transfer ring element +buffer is copied to pending list. Reader is unblocked and data is copied to +userspace buffer. Transfer ring element buffer is queued back to downlink +channel transfer ring. + +write +- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll + + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. Returns EPOLLERR when UCI driver is removed. ring is not empty. When the uplink channel transfer ring is non-empty, more data may be sent to the device. Returns EPOLLERR when UCI driver is removed. Done + +release +--- + +Decrements UCI device reference count and UCI channel reference count upon last +release(). UCI channel clean up is performed. MHI channel moves to disable +state and inbound buffers are freed. Decrements UCI device reference count and UCI channel reference count. Upon last release() UCI channel clean up is performed. MHI channel moves to disable state and inbound buffers are freed. Done. + +Usage += + +Device file node is created with format:- + +/dev/ + +mhi_device_name includes mhi controller name and the name of the MHI channel +being used by MHI client in userspace to send or receive data using MHI +protocol. + +There is a separate character device file node created for each channel +specified in MHI device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +Qualcomm MSM Interface(QMI) Channel +--- + +Qualcomm MSM Interface(QMI) is a modem control messaging protocol used to +communicate between software components in the modem and other peripheral +subsystems. QMI communication is of request/response type or an unsolicited +event type. libqmi is userspace MHI client which communicates to a QMI service +using UCI device. It sends a QMI request to a QMI service using MHI channel 14 +or 16. QMI response is received using MHI channel 15 or 17 respectively. libqmi +is a glib-based library for talking to WWAN modems and devices which speaks QMI +protocol. For more information about libqmi please refer +https://www.freedesktop.org/wiki/Software/libqmi/ + +Usage Example +~ + +QMI command to retrieve device mode +$ sudo qmicli -d /dev/mhi0_QMI --dms-get-model +[/dev/mhi0_QMI] Device model retrieved: + Model: 'FN980m' + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diagnostic +client using DIAG channel 4 (Host to device) and 5 (Device to Host). Thanks, Hemant -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v3 7/7] bus: mhi: Improve documentation on channel transfer setup APIs
On 12/2/20 3:40 PM, Bhaumik Bhatt wrote: The mhi_prepare_for_transfer() and mhi_unprepare_from_transfer() APIs could use better explanation, especially with the addition of two new APIs to start and stop the transfers on channels. Add better set of information for those APIs. Signed-off-by: Bhaumik Bhatt --- Reviewed-by: Hemant Kumar The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v3 5/7] bus: mhi: core: Check execution environment for channel before issuing reset
On 12/2/20 3:40 PM, Bhaumik Bhatt wrote: A client can attempt to unprepare certain channels for transfer even after the execution environment they are supposed to run in has changed. In the event that happens, the device need not be notified of the reset and the host can proceed with clean up for the channel context and memory allocated for it on the host. Signed-off-by: Bhaumik Bhatt Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v3 3/7] bus: mhi: core: Improvements to the channel handling state machine
On 12/2/20 3:40 PM, Bhaumik Bhatt wrote: Add support to enable sending the stop channel command and improve the channel handling state machine such that all commands go through a common function. This can help ensure that the state machine is not violated in any way and adheres to the MHI specification. Signed-off-by: Bhaumik Bhatt --- Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v3 4/7] bus: mhi: core: Add support to stop or start channel data transfers
Hi Bhaumik,
On 12/2/20 3:40 PM, Bhaumik Bhatt wrote:
Some MHI client drivers may want to request a pause or halt of
data transfer activity on their channels. Support for this does
not exist and must be introduced, wherein the channel context is
not reset or cleared but only the STOP channel command is issued.
This would need to be paired with an API that allows resuming the
data transfer activity on channels by use of the START channel
command. This API assumes that the context information is already
is it a better option to make sure channel context is setup as this is
an exported API. Hence check for channel context bail out in case
channel context is not setup with an err msg ?
setup. Enable this using two new APIs, mhi_start_transfer() and
mhi_stop_transfer().
Signed-off-by: Bhaumik Bhatt
---
drivers/bus/mhi/core/main.c | 41 +
include/linux/mhi.h | 19 +++
2 files changed, 60 insertions(+)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 4cc5ced..2e4b34a 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -1552,6 +1552,47 @@ void mhi_unprepare_from_transfer(struct mhi_device
*mhi_dev)
}
EXPORT_SYMBOL_GPL(mhi_unprepare_from_transfer);
+static int mhi_update_transfer_state(struct mhi_device *mhi_dev,
+enum mhi_ch_state_type to_state)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ struct mhi_chan *mhi_chan;
+ int dir, ret;
+
+ for (dir = 0; dir < 2; dir++) {
+ mhi_chan = dir ? mhi_dev->ul_chan : mhi_dev->dl_chan;
+
+ if (!mhi_chan)
+ continue;
+
+ /*
+* Bail out if one of the channels fail as client will reset
+* both upon failure
+*/
+ mutex_lock(_chan->mutex);
+ ret = mhi_update_channel_state(mhi_cntrl, mhi_chan, to_state);
+ if (ret) {
+ mutex_unlock(_chan->mutex);
+ return ret;
+ }
+ mutex_unlock(_chan->mutex);
+ }
+
+ return 0;
+}
+
+int mhi_stop_transfer(struct mhi_device *mhi_dev)
+{
+ return mhi_update_transfer_state(mhi_dev, MHI_CH_STATE_TYPE_STOP);
+}
+EXPORT_SYMBOL_GPL(mhi_stop_transfer);
+
+int mhi_start_transfer(struct mhi_device *mhi_dev)
+{
+ return mhi_update_transfer_state(mhi_dev, MHI_CH_STATE_TYPE_START);
+}
+EXPORT_SYMBOL_GPL(mhi_start_transfer);
+
int mhi_poll(struct mhi_device *mhi_dev, u32 budget)
{
struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index aa9757e..35779a0 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -704,6 +704,25 @@ int mhi_prepare_for_transfer(struct mhi_device *mhi_dev);
void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev);
/**
+ * mhi_stop_transfer - Pauses ongoing channel activity by issuing the STOP
+ * channel command to both UL and DL channels. This command
+ * does not reset the channel context and the client
drivers
+ * can issue mhi_start_transfer to resume activity.
+ * @mhi_dev: Device associated with the channels
+ */
+int mhi_stop_transfer(struct mhi_device *mhi_dev);
+
+/**
+ * mhi_start_transfer - Resumes channel activity by issuing the START channel
+ * command to both UL and DL channels. This command
assumes
+ * the channel context is already setup and the client
+ * drivers can issue mhi_stop_transfer to pause activity
if
+ * required.
+ * @mhi_dev: Device associated with the channels
+ */
+int mhi_start_transfer(struct mhi_device *mhi_dev);
+
+/**
* mhi_poll - Poll for any available data in DL direction
* @mhi_dev: Device associated with the channels
* @budget: # of events to process
Overall change looks good.
Thanks,
Hemant
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Re: [PATCH v3 2/7] bus: mhi: core: Allow channel to be disabled from stopped state
On 12/2/20 3:40 PM, Bhaumik Bhatt wrote: If a channel was explicitly stopped but not reset, allow it to move to a disabled state so the channel context can be cleaned up. As the channel remained in a stopped state, its context was not reset and cleared, which needs to be done if a client driver module is unloaded or a device crash occurs. Signed-off-by: Bhaumik Bhatt --- Reviewed-by: Hemant Kumar -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v3 1/7] bus: mhi: core: Allow receiving a STOP channel command response
Hi Bhaumik, On 12/2/20 3:40 PM, Bhaumik Bhatt wrote: Add support to receive the response to a STOP channel command to the How about saying "Add support to send the STOP channel command ? MHI bus. If a client would like to STOP a channel instead of issuing a RESET to it, this would provide support for it. Signed-off-by: Bhaumik Bhatt --- drivers/bus/mhi/core/main.c | 5 + 1 file changed, 5 insertions(+) diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c index 702c31b..a7bb8a7 100644 --- a/drivers/bus/mhi/core/main.c +++ b/drivers/bus/mhi/core/main.c @@ -1193,6 +1193,11 @@ int mhi_send_cmd(struct mhi_controller *mhi_cntrl, cmd_tre->dword[0] = MHI_TRE_CMD_RESET_DWORD0; cmd_tre->dword[1] = MHI_TRE_CMD_RESET_DWORD1(chan); break; + case MHI_CMD_STOP_CHAN: + cmd_tre->ptr = MHI_TRE_CMD_STOP_PTR; + cmd_tre->dword[0] = MHI_TRE_CMD_STOP_DWORD0; + cmd_tre->dword[1] = MHI_TRE_CMD_STOP_DWORD1(chan); + break; case MHI_CMD_START_CHAN: cmd_tre->ptr = MHI_TRE_CMD_START_PTR; cmd_tre->dword[0] = MHI_TRE_CMD_START_DWORD0; Thanks, Hemant -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v3 6/7] bus: mhi: core: Remove __ prefix for MHI channel unprepare function
On 12/2/20 3:40 PM, Bhaumik Bhatt wrote: The __mhi_unprepare_channel() API does not require the __ prefix. Get rid of it and make the internal function consistent with the other function names. Signed-off-by: Bhaumik Bhatt Reviewed-by: Manivannan Sadhasivam Reviewed-by: Hemant Kumar The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v14 4/4] bus: mhi: Add userspace client interface driver
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
/dev/
Currently it supports QMI channel.
Signed-off-by: Hemant Kumar
Reviewed-by: Manivannan Sadhasivam
Tested-by: Loic Poulain
---
drivers/bus/mhi/Kconfig | 13 +
drivers/bus/mhi/Makefile | 3 +
drivers/bus/mhi/uci.c| 664 +++
3 files changed, 680 insertions(+)
create mode 100644 drivers/bus/mhi/uci.c
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index da5cd0c..5194e8e 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -29,3 +29,16 @@ config MHI_BUS_PCI_GENERIC
This driver provides MHI PCI controller driver for devices such as
Qualcomm SDX55 based PCIe modems.
+config MHI_UCI
+ tristate "MHI UCI"
+ depends on MHI_BUS
+ help
+ MHI based Userspace Client Interface (UCI) driver is used for
+ transferring raw data between host and device using standard file
+ operations from userspace. Open, read, write, poll and close
+ operations are supported by this driver. Please check
+ mhi_uci_match_table for all supported channels that are exposed to
+ userspace.
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_uci.
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 0a2d778..69f2111 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -4,3 +4,6 @@ obj-y += core/
obj-$(CONFIG_MHI_BUS_PCI_GENERIC) += mhi_pci_generic.o
mhi_pci_generic-y += pci_generic.o
+# MHI client
+mhi_uci-y := uci.o
+obj-$(CONFIG_MHI_UCI) += mhi_uci.o
diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c
new file mode 100644
index 000..1df2377
--- /dev/null
+++ b/drivers/bus/mhi/uci.c
@@ -0,0 +1,664 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/
+
+#include
+#include
+#include
+#include
+#include
+
+#define MHI_UCI_DRIVER_NAME "mhi_uci"
+#define MHI_MAX_UCI_MINORS 128
+
+static DEFINE_IDR(uci_idr);
+static DEFINE_MUTEX(uci_drv_mutex);
+static struct class *uci_dev_class;
+static int uci_dev_major;
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_pending_lock: spin lock for dl_pending list
+ * @dl_pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
+
+/**
+ * struct uci_buf - UCI buffer
+ * @data: data buffer
+ * @len: length of data buffer
+ * @node: list node of the UCI buffer
+ */
+struct uci_buf {
+ void *data;
+ size_t len;
+ struct list_head node;
+};
+
+/**
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Flag to track the state of the UCI device
+ * @lock: mutex lock to manage uchan object
+ * @ref_count: uci_dev reference count
+ */
+struct uci_dev {
+ unsigned int minor;
+ struct mhi_device *mhi_dev;
+ struct uci_chan *uchan;
+ size_t mtu;
+ bool enabled;
+
+ /* synchronize open, release and driver remove */
+ struct mutex lock;
+ struct kref ref_count;
+};
+
+static void mhi_uci_dev_chan_release(struct kref *ref)
+{
+ struct uci_buf *buf_itr, *tmp;
+ struct uci_chan *uchan =
+ container_of(ref, struct uci_chan, ref_count);
+
+ if (
[PATCH v14 3/4] docs: Add documentation for userspace client interface
MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently QMI MHI channel is supported by this driver. Signed-off-by: Hemant Kumar --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 94 + 2 files changed, 95 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..9603f92 --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,94 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + +UCI driver enables userspace clients to communicate to external MHI devices +like modem and WLAN. UCI driver probe creates standard character device file +nodes for userspace clients to perform open, read, write, poll and release file +operations. UCI device object represents UCI device file node which gets +instantiated as part of MHI UCI driver probe. UCI channel object represents +MHI uplink or downlink channel. + +Operations +== + +open + + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read + + +When data transfer is completed on downlink channel, transfer ring element +buffer is copied to pending list. Reader is unblocked and data is copied to +userspace buffer. Transfer ring element buffer is queued back to downlink +channel transfer ring. + +write +- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll + + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. Returns EPOLLERR when UCI driver is removed. + +release +--- + +Decrements UCI device reference count and UCI channel reference count upon last +release(). UCI channel clean up is performed. MHI channel moves to disable +state and inbound buffers are freed. + +Usage += + +Device file node is created with format:- + +/dev/ + +mhi_device_name includes mhi controller name and the name of the MHI channel +being used by MHI client in userspace to send or receive data using MHI +protocol. + +There is a separate character device file node created for each channel +specified in MHI device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +Qualcomm MSM Interface(QMI) Channel +--- + +Qualcomm MSM Interface(QMI) is a modem control messaging protocol used to +communicate between software components in the modem and other peripheral +subsystems. QMI communication is of request/response type or an unsolicited +event type. libqmi is userspace MHI client which communicates to a QMI service +using UCI device. It sends a QMI request to a QMI service using MHI channel 14 +or 16. QMI response is received using MHI channel 15 or 17 respectively. libqmi +is a glib-based library for talking to WWAN modems and devices which speaks QMI +protocol. For more information about libqmi please refer +https://www.freedesktop.org/wiki/Software/libqmi/ + +Usage Example +~ + +QMI command to retrieve device mode +$ sudo qmicli -d /dev/mhi0_QMI --dms-get-model +[/dev/mhi0_QMI] Device model retrieved: +Model: 'FN980m' + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diagnostic +client using DIAG channel 4 (Host to device) and 5 (Device to Host). -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v14 0/4] userspace MHI client interface driver
This patch series adds support for UCI driver. UCI driver enables userspace clients to communicate to external MHI devices like modem and WLAN. UCI driver probe creates standard character device file nodes for userspace clients to perform open, read, write, poll and release file operations. These file operations call MHI core layer APIs to perform data transfer using MHI bus to communicate with MHI device. Patch is tested using arm64 and x86 based platform. V14: - Fixed device file node format to /dev/ instead of /dev/mhi_ because "mhi" is already part of mhi device name. For example old format: /dev/mhi_mhi0_QMI new format: /dev/mhi0_QMI. - Updated MHI documentation to reflect index mhi controller name in QMI usage example. V13: - Removed LOOPBACK channel from mhi_device_id table from this patch series. Pushing a new patch series to add support for LOOPBACK channel and the user space test application. Also removed the description from kernel documentation. - Added QMI channel to mhi_device_id table. QMI channel has existing libqmi support from user space. - Updated kernel Documentation for QMI channel and provided external reference for libqmi. - Updated device file node name by appending mhi device name only, which already includes mhi controller device name. V12: - Added loopback test driver under selftest/drivers/mhi. Updated kernel documentation for the usage of the loopback test application. - Addressed review comments for renaming variable names, updated inline comments and removed two redundant dev_dbg. V11: - Fixed review comments for UCI documentation by expanding TLAs and rewording some sentences. V10: - Replaced mutex_lock with mutex_lock_interruptible in read() and write() file ops call back. V9: - Renamed dl_lock to dl_pending _lock and pending list to dl_pending for clarity. - Used read lock to protect cur_buf. - Change transfer status check logic and only consider 0 and -EOVERFLOW as only success. - Added __int to module init function. - Print channel name instead of minor number upon successful probe. V8: - Fixed kernel test robot compilation error by changing %lu to %zu for size_t. - Replaced uci with UCI in Kconfig, commit text, and comments in driver code. - Fixed minor style related comments. V7: - Decoupled uci device and uci channel objects. uci device is associated with device file node. uci channel is associated with MHI channels. uci device refers to uci channel to perform MHI channel operations for device file operations like read() and write(). uci device increments its reference count for every open(). uci device calls mhi_uci_dev_start_chan() to start the MHI channel. uci channel object is tracking number of times MHI channel is referred. This allows to keep the MHI channel in start state until last release() is called. After that uci channel reference count goes to 0 and uci channel clean up is performed which stops the MHI channel. After the last call to release() if driver is removed uci reference count becomes 0 and uci object is cleaned up. - Use separate uci channel read and write lock to fine grain locking between reader and writer. - Use uci device lock to synchronize open, release and driver remove. - Optimize for downlink only or uplink only UCI device. V6: - Moved uci.c to mhi directory. - Updated Kconfig to add module information. - Updated Makefile to rename uci object file name as mhi_uci - Removed kref for open count V5: - Removed mhi_uci_drv structure. - Used idr instead of creating global list of uci devices. - Used kref instead of local ref counting for uci device and open count. - Removed unlikely macro. V4: - Fix locking to protect proper struct members. - Updated documentation describing uci client driver use cases. - Fixed uci ref counting in mhi_uci_open for error case. - Addressed style related review comments. V3: Added documentation for MHI UCI driver. V2: - Added mutex lock to prevent multiple readers to access same - mhi buffer which can result into use after free. Hemant Kumar (4): bus: mhi: core: Add helper API to return number of free TREs bus: mhi: core: Move MHI_MAX_MTU to external header file docs: Add documentation for userspace client interface bus: mhi: Add userspace client interface driver Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 94 ++ drivers/bus/mhi/Kconfig | 13 + drivers/bus/mhi/Makefile| 3 + drivers/bus/mhi/core/internal.h | 1 - drivers/bus/mhi/core/main.c | 12 + drivers/bus/mhi/uci.c | 664 include/linux/mhi.h | 12 + 8 files changed, 799 insertions(+), 1 deletion(-) create mode 100644 Documentation/mhi/uci.rst create mode 100644 drivers/bus/mhi/uci.c -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v14 1/4] bus: mhi: core: Add helper API to return number of free TREs
Introduce mhi_get_free_desc_count() API to return number
of TREs available to queue buffer. MHI clients can use this
API to know before hand if ring is full without calling queue
API.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/main.c | 12
include/linux/mhi.h | 9 +
2 files changed, 21 insertions(+)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 702c31b..74a25e7 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -260,6 +260,18 @@ int mhi_destroy_device(struct device *dev, void *data)
return 0;
}
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ struct mhi_chan *mhi_chan = (dir == DMA_TO_DEVICE) ?
+ mhi_dev->ul_chan : mhi_dev->dl_chan;
+ struct mhi_ring *tre_ring = _chan->tre_ring;
+
+ return get_nr_avail_ring_elements(mhi_cntrl, tre_ring);
+}
+EXPORT_SYMBOL_GPL(mhi_get_free_desc_count);
+
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
{
struct mhi_driver *mhi_drv;
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index aa9757e..e36d575 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -599,6 +599,15 @@ void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl,
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason);
/**
+ * mhi_get_free_desc_count - Get transfer ring length
+ * Get # of TD available to queue buffers
+ * @mhi_dev: Device associated with the channels
+ * @dir: Direction of the channel
+ */
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir);
+
+/**
* mhi_prepare_for_power_up - Do pre-initialization before power up.
*This is optional, call this before power up if
*the controller does not want bus framework to
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v14 2/4] bus: mhi: core: Move MHI_MAX_MTU to external header file
Currently this macro is defined in internal MHI header as
a TRE length mask. Moving it to external header allows MHI
client drivers to set this upper bound for the transmit
buffer size.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/internal.h | 1 -
include/linux/mhi.h | 3 +++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 6f80ec3..2b9c063 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -453,7 +453,6 @@ enum mhi_pm_state {
#define CMD_EL_PER_RING128
#define PRIMARY_CMD_RING 0
#define MHI_DEV_WAKE_DB127
-#define MHI_MAX_MTU0x
#define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1)
enum mhi_er_type {
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index e36d575..f072605 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -15,6 +15,9 @@
#include
#include
+/* MHI client drivers to set this upper bound for tx buffer */
+#define MHI_MAX_MTU 0x
+
#define MHI_MAX_OEM_PK_HASH_SEGMENTS 16
struct mhi_chan;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Re: [PATCH v13 4/4] bus: mhi: Add userspace client interface driver
Hi Loic,
On 12/1/20 10:04 AM, Jeffrey Hugo wrote:
On 12/1/2020 11:05 AM, Loic Poulain wrote:
On Tue, 1 Dec 2020 at 18:51, Jeffrey Hugo wrote:
On 12/1/2020 10:52 AM, Loic Poulain wrote:
On Tue, 1 Dec 2020 at 18:37, Jeffrey Hugo wrote:
On 12/1/2020 10:36 AM, Loic Poulain wrote:
On Tue, 1 Dec 2020 at 02:16, Hemant Kumar
wrote:
Hi Loic,
On 11/30/20 10:22 AM, Loic Poulain wrote:
On Sat, 28 Nov 2020 at 04:26, Hemant Kumar
wrote:
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file
operations.
Driver instantiates UCI device object which is associated to
device
file node. UCI device object instantiates UCI channel object
when device
file node is opened. UCI channel object is used to manage MHI
channels
by calling MHI core APIs for read and write operations. MHI
channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node.
Device
file node is created with format
[...]
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+ * protects pending list in bh context, channel
release, read and
+ * poll
+ */
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
[...]
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Flag to track the state of the UCI device
+ * @lock: mutex lock to manage uchan object
+ * @ref_count: uci_dev reference count
+ */
+struct uci_dev {
+ unsigned int minor;
+ struct mhi_device *mhi_dev;
+ struct uci_chan *uchan;
Why a pointer to uci_chan and not just plainly integrating the
structure here, AFAIU uci_chan describes the channels and is just a
subpart of uci_dev. That would reduce the number of dynamic
allocations you manage and the extra kref. do you even need a
separate
structure for this?
This goes back to one of my patch versions i tried to address
concern
from Greg. Since we need to ref count the channel as well as the uci
device i decoupled the two objects and used two reference counts
for two
different objects.
What Greg complained about is the two kref in the same structure and
that you were using kref as an open() counter. But splitting your
struct in two in order to keep the two kref does not make the much
code better (and simpler). I'm still a bit puzzled about the driver
complexity, it's supposed to be just a passthrough interface to MHI
after all.
I would suggest several changes, that IMHO would simplify reviewing:
- Use only one structure representing the 'uci' context (uci_dev)
- Keep the read path simple (mhi_uci_read), do no use an intermediate
cur_buf pointer, only dequeue the buffer when it is fully consumed.
- As I commented before, take care of the dl_pending list access
concurrency, even in wait_event.
- You don't need to count the number of open() calls, AFAIK,
mhi_prepare_for_transfer() simply fails if channels are already
started...
Unless I missed something, you seem to have ignored the root issue
that
Hemant needs to solve, which is when to call
mhi_unprepare_for_transfer(). You can't just call that when
close() is
called because there might be multiple users, and each one is going to
trigger a close(), so you need to know how many close() instances to
expect, and only call mhi_unprepare_for_transfer() for the last one.
That one part of his problem, yes, but if you unconditionally call
mhi_prepare_for_transfer in open(), it should fail for subsequent
users, and so only one user will successfully open the device.
I'm pretty sure that falls under "trying to prevent users from opening a
device" which Greg gave a pretty strong NACK to. So, that's not a
solution.
That would deserve clarification since other drivers like
virtio_console clearly prevent that (guest_connected).
Quoting Greg from the source - https://lkml.org/lkml/2020/9/17/873
"
I told you before, do not try to keep a device node from being opened
multiple times, as it will always fail (think about passing file handles
around between programs...)
If userspace wants to do this, it will do it. If your driver can't
handle that, that's fine, userspace will learn not to do that. But the
kernel can not prevent this from happening.
"
So, the complete problem is -
N users need to be able to use the device (and by proxy, the channel)
concurrently, but prepare needs to be called on the first user coming
into the pi
Re: [PATCH v13 4/4] bus: mhi: Add userspace client interface driver
Hi Loic,
On 11/30/20 10:22 AM, Loic Poulain wrote:
On Sat, 28 Nov 2020 at 04:26, Hemant Kumar wrote:
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
[...]
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
[...]
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Flag to track the state of the UCI device
+ * @lock: mutex lock to manage uchan object
+ * @ref_count: uci_dev reference count
+ */
+struct uci_dev {
+ unsigned int minor;
+ struct mhi_device *mhi_dev;
+ struct uci_chan *uchan;
Why a pointer to uci_chan and not just plainly integrating the
structure here, AFAIU uci_chan describes the channels and is just a
subpart of uci_dev. That would reduce the number of dynamic
allocations you manage and the extra kref. do you even need a separate
structure for this?
This goes back to one of my patch versions i tried to address concern
from Greg. Since we need to ref count the channel as well as the uci
device i decoupled the two objects and used two reference counts for two
different objects.
Copying from V7 patch history
V7:
- Decoupled uci device and uci channel objects. uci device is
associated with device file node. uci channel is associated
with MHI channels. uci device refers to uci channel to perform
MHI channel operations for device file operations like read()
and write(). uci device increments its reference count for
every open(). uci device calls mhi_uci_dev_start_chan() to start
the MHI channel. uci channel object is tracking number of times
MHI channel is referred. This allows to keep the MHI channel in
start state until last release() is called. After that uci channel
reference count goes to 0 and uci channel clean up is performed
which stops the MHI channel. After the last call to release() if
driver is removed uci reference count becomes 0 and uci object is
cleaned up.
[...]
+static int mhi_uci_dev_start_chan(struct uci_dev *udev)
+{
+ int ret = 0;
+ struct uci_chan *uchan;
+
+ mutex_lock(>lock);
+ if (!udev->uchan || !kref_get_unless_zero(>uchan->ref_count)) {
This test is suspicious, kref_get_unless_zero should be enough to test, right?
kref_get_unless_zero is de-referencing uchan->ref_count for the first
open uchan is set to NULL, for that NULL check is added for uchan.
if (kref_get_unless_zero(>ref))
goto skip_init;
+ uchan = kzalloc(sizeof(*uchan), GFP_KERNEL);
+ if (!uchan) {
+ ret = -ENOMEM;
+ goto error_chan_start;
+ }
+
+ udev->uchan = uchan;
+ uchan->udev = udev;
+ init_waitqueue_head(>ul_wq);
+ init_waitqueue_head(>dl_wq);
+ mutex_init(>write_lock);
+ mutex_init(>read_lock);
+ spin_lock_init(>dl_pending_lock);
+ INIT_LIST_HEAD(>dl_pending);
+
+ ret = mhi_prepare_for_transfer(udev->mhi_dev);
+ if (ret) {
+ dev_err(>mhi_dev->dev, "Error starting transfer
channels\n");
+ goto error_chan_cleanup;
+ }
+
+ ret = mhi_queue_inbound(udev);
+ if (ret)
+ goto error_chan_cleanup;
+
+ kref_init(>ref_count);
+ }
+
+ mutex_unlock(>lock);
+
+ return 0;
+
+error_chan_cleanup:
+ mhi_uci_dev_chan_release(>ref_count);
+error_chan_start:
+ mutex_unlock(>lock);
+ return ret;
+}
Regards,
Loic
Thanks,
Hemant
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Re: [PATCH v13 4/4] bus: mhi: Add userspace client interface driver
Hi Mani, On 11/27/20 10:11 PM, Manivannan Sadhasivam wrote: Hi Hemant, On Fri, Nov 27, 2020 at 07:26:06PM -0800, Hemant Kumar wrote: This MHI client driver allows userspace clients to transfer raw data between MHI device and host using standard file operations. Driver instantiates UCI device object which is associated to device file node. UCI device object instantiates UCI channel object when device file node is opened. UCI channel object is used to manage MHI channels by calling MHI core APIs for read and write operations. MHI channels are started as part of device open(). MHI channels remain in start state until last release() is called on UCI device file node. Device file node is created with format /dev/mhi_ Currently it supports QMI channel. Thanks for the update. This patch looks good to me. But as I'm going to apply Loic's "bus: mhi: core: Indexed MHI controller name" patch, you need to update the documentation accordingly. This is what i added in documentation on v13 Device file node is created with format:- /dev/mhi_ mhi_device_name includes mhi controller name and the name of the MHI channel being used by MHI client in userspace to send or receive data using MHI protocol. Loic's patch is going to update the controller name as indexed controller name, which goes fine with or without his change going first. For example: With Loic's change name of device node would be /dev/mhi_mhi0_QMI Without Loic's change it would be /dev/mhi_:00:01.2_QMI Please let me know if i am missing something. Thanks, Hemant Signed-off-by: Hemant Kumar Reviewed-by: Manivannan Sadhasivam Thanks, Mani [..] -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v13 2/4] bus: mhi: core: Move MHI_MAX_MTU to external header file
Currently this macro is defined in internal MHI header as
a TRE length mask. Moving it to external header allows MHI
client drivers to set this upper bound for the transmit
buffer size.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/internal.h | 1 -
include/linux/mhi.h | 3 +++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 6f80ec3..2b9c063 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -453,7 +453,6 @@ enum mhi_pm_state {
#define CMD_EL_PER_RING128
#define PRIMARY_CMD_RING 0
#define MHI_DEV_WAKE_DB127
-#define MHI_MAX_MTU0x
#define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1)
enum mhi_er_type {
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index b3bc966..fc903b2 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -15,6 +15,9 @@
#include
#include
+/* MHI client drivers to set this upper bound for tx buffer */
+#define MHI_MAX_MTU 0x
+
#define MHI_MAX_OEM_PK_HASH_SEGMENTS 16
struct mhi_chan;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v13 1/4] bus: mhi: core: Add helper API to return number of free TREs
Introduce mhi_get_free_desc_count() API to return number
of TREs available to queue buffer. MHI clients can use this
API to know before hand if ring is full without calling queue
API.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/main.c | 12
include/linux/mhi.h | 9 +
2 files changed, 21 insertions(+)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 4eb93d8..defd579a 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -260,6 +260,18 @@ int mhi_destroy_device(struct device *dev, void *data)
return 0;
}
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ struct mhi_chan *mhi_chan = (dir == DMA_TO_DEVICE) ?
+ mhi_dev->ul_chan : mhi_dev->dl_chan;
+ struct mhi_ring *tre_ring = _chan->tre_ring;
+
+ return get_nr_avail_ring_elements(mhi_cntrl, tre_ring);
+}
+EXPORT_SYMBOL_GPL(mhi_get_free_desc_count);
+
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
{
struct mhi_driver *mhi_drv;
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index d31efcf..b3bc966 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -597,6 +597,15 @@ void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl,
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason);
/**
+ * mhi_get_free_desc_count - Get transfer ring length
+ * Get # of TD available to queue buffers
+ * @mhi_dev: Device associated with the channels
+ * @dir: Direction of the channel
+ */
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir);
+
+/**
* mhi_prepare_for_power_up - Do pre-initialization before power up.
*This is optional, call this before power up if
*the controller does not want bus framework to
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v13 0/4] userspace MHI client interface driver
This patch series adds support for UCI driver. UCI driver enables userspace clients to communicate to external MHI devices like modem and WLAN. UCI driver probe creates standard character device file nodes for userspace clients to perform open, read, write, poll and release file operations. These file operations call MHI core layer APIs to perform data transfer using MHI bus to communicate with MHI device. Patch is tested using arm64 based platform. V13: - Removed LOOPBACK channel from mhi_device_id table from this patch series. Pushing a new patch series to add support for LOOPBACK channel and the user space test application. Also removed the description from kernel documentation. - Added QMI channel to mhi_device_id table. QMI channel has existing libqmi support from user space. - Updated kernel Documentation for QMI channel and provided external reference for libqmi. - Updated device file node name by appending mhi device name only, which already includes mhi controller device name. V12: - Added loopback test driver under selftest/drivers/mhi. Updated kernel documentation for the usage of the loopback test application. - Addressed review comments for renaming variable names, updated inline comments and removed two redundant dev_dbg. V11: - Fixed review comments for UCI documentation by expanding TLAs and rewording some sentences. V10: - Replaced mutex_lock with mutex_lock_interruptible in read() and write() file ops call back. V9: - Renamed dl_lock to dl_pending _lock and pending list to dl_pending for clarity. - Used read lock to protect cur_buf. - Change transfer status check logic and only consider 0 and -EOVERFLOW as only success. - Added __int to module init function. - Print channel name instead of minor number upon successful probe. V8: - Fixed kernel test robot compilation error by changing %lu to %zu for size_t. - Replaced uci with UCI in Kconfig, commit text, and comments in driver code. - Fixed minor style related comments. V7: - Decoupled uci device and uci channel objects. uci device is associated with device file node. uci channel is associated with MHI channels. uci device refers to uci channel to perform MHI channel operations for device file operations like read() and write(). uci device increments its reference count for every open(). uci device calls mhi_uci_dev_start_chan() to start the MHI channel. uci channel object is tracking number of times MHI channel is referred. This allows to keep the MHI channel in start state until last release() is called. After that uci channel reference count goes to 0 and uci channel clean up is performed which stops the MHI channel. After the last call to release() if driver is removed uci reference count becomes 0 and uci object is cleaned up. - Use separate uci channel read and write lock to fine grain locking between reader and writer. - Use uci device lock to synchronize open, release and driver remove. - Optimize for downlink only or uplink only UCI device. V6: - Moved uci.c to mhi directory. - Updated Kconfig to add module information. - Updated Makefile to rename uci object file name as mhi_uci - Removed kref for open count V5: - Removed mhi_uci_drv structure. - Used idr instead of creating global list of uci devices. - Used kref instead of local ref counting for uci device and open count. - Removed unlikely macro. V4: - Fix locking to protect proper struct members. - Updated documentation describing uci client driver use cases. - Fixed uci ref counting in mhi_uci_open for error case. - Addressed style related review comments. V3: Added documentation for MHI UCI driver. V2: - Added mutex lock to prevent multiple readers to access same - mhi buffer which can result into use after free. Hemant Kumar (4): bus: mhi: core: Add helper API to return number of free TREs bus: mhi: core: Move MHI_MAX_MTU to external header file docs: Add documentation for userspace client interface bus: mhi: Add userspace client interface driver Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 94 ++ drivers/bus/mhi/Kconfig | 13 + drivers/bus/mhi/Makefile| 3 + drivers/bus/mhi/core/internal.h | 1 - drivers/bus/mhi/core/main.c | 12 + drivers/bus/mhi/uci.c | 665 include/linux/mhi.h | 12 + 8 files changed, 800 insertions(+), 1 deletion(-) create mode 100644 Documentation/mhi/uci.rst create mode 100644 drivers/bus/mhi/uci.c -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v13 4/4] bus: mhi: Add userspace client interface driver
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
/dev/mhi_
Currently it supports QMI channel.
Signed-off-by: Hemant Kumar
---
drivers/bus/mhi/Kconfig | 13 +
drivers/bus/mhi/Makefile | 3 +
drivers/bus/mhi/uci.c| 665 +++
3 files changed, 681 insertions(+)
create mode 100644 drivers/bus/mhi/uci.c
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index da5cd0c..5194e8e 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -29,3 +29,16 @@ config MHI_BUS_PCI_GENERIC
This driver provides MHI PCI controller driver for devices such as
Qualcomm SDX55 based PCIe modems.
+config MHI_UCI
+ tristate "MHI UCI"
+ depends on MHI_BUS
+ help
+ MHI based Userspace Client Interface (UCI) driver is used for
+ transferring raw data between host and device using standard file
+ operations from userspace. Open, read, write, poll and close
+ operations are supported by this driver. Please check
+ mhi_uci_match_table for all supported channels that are exposed to
+ userspace.
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_uci.
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 0a2d778..69f2111 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -4,3 +4,6 @@ obj-y += core/
obj-$(CONFIG_MHI_BUS_PCI_GENERIC) += mhi_pci_generic.o
mhi_pci_generic-y += pci_generic.o
+# MHI client
+mhi_uci-y := uci.o
+obj-$(CONFIG_MHI_UCI) += mhi_uci.o
diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c
new file mode 100644
index 000..fb9c183
--- /dev/null
+++ b/drivers/bus/mhi/uci.c
@@ -0,0 +1,665 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/
+
+#include
+#include
+#include
+#include
+#include
+
+#define MHI_DEVICE_NAME "mhi"
+#define MHI_UCI_DRIVER_NAME "mhi_uci"
+#define MHI_MAX_UCI_MINORS 128
+
+static DEFINE_IDR(uci_idr);
+static DEFINE_MUTEX(uci_drv_mutex);
+static struct class *uci_dev_class;
+static int uci_dev_major;
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_pending_lock: spin lock for dl_pending list
+ * @dl_pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
+
+/**
+ * struct uci_buf - UCI buffer
+ * @data: data buffer
+ * @len: length of data buffer
+ * @node: list node of the UCI buffer
+ */
+struct uci_buf {
+ void *data;
+ size_t len;
+ struct list_head node;
+};
+
+/**
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Flag to track the state of the UCI device
+ * @lock: mutex lock to manage uchan object
+ * @ref_count: uci_dev reference count
+ */
+struct uci_dev {
+ unsigned int minor;
+ struct mhi_device *mhi_dev;
+ struct uci_chan *uchan;
+ size_t mtu;
+ bool enabled;
+
+ /* synchronize open, release and driver remove */
+ struct mutex lock;
+ struct kref ref_count;
+};
+
+static void mhi_uci_dev_chan_release(struct kref *ref)
+{
+ struct uci_buf *buf_itr, *tmp;
+ struct uci_chan *uchan =
+ container_of(ref, struct uci_chan, ref_count);
+
+ if (uchan->udev->enabled)
+ mhi_unprepar
[PATCH v13 3/4] docs: Add documentation for userspace client interface
MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently QMI MHI channel is supported by this driver. Signed-off-by: Hemant Kumar --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 94 + 2 files changed, 95 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..ad22650 --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,94 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + +UCI driver enables userspace clients to communicate to external MHI devices +like modem and WLAN. UCI driver probe creates standard character device file +nodes for userspace clients to perform open, read, write, poll and release file +operations. UCI device object represents UCI device file node which gets +instantiated as part of MHI UCI driver probe. UCI channel object represents +MHI uplink or downlink channel. + +Operations +== + +open + + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read + + +When data transfer is completed on downlink channel, transfer ring element +buffer is copied to pending list. Reader is unblocked and data is copied to +userspace buffer. Transfer ring element buffer is queued back to downlink +channel transfer ring. + +write +- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll + + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. Returns EPOLLERR when UCI driver is removed. + +release +--- + +Decrements UCI device reference count and UCI channel reference count upon last +release(). UCI channel clean up is performed. MHI channel moves to disable +state and inbound buffers are freed. + +Usage += + +Device file node is created with format:- + +/dev/mhi_ + +mhi_device_name includes mhi controller name and the name of the MHI channel +being used by MHI client in userspace to send or receive data using MHI +protocol. + +There is a separate character device file node created for each channel +specified in MHI device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +Qualcomm MSM Interface(QMI) Channel +--- + +Qualcomm MSM Interface(QMI) is a modem control messaging protocol used to +communicate between software components in the modem and other peripheral +subsystems. QMI communication is of request/response type or an unsolicited +event type. libqmi is userspace MHI client which communicates to a QMI service +using UCI device. It sends a QMI request to a QMI service using MHI channel 14 +or 16. QMI response is received using MHI channel 15 or 17 respectively. libqmi +is a glib-based library for talking to WWAN modems and devices which speaks QMI +protocol. For more information about libqmi please refer +https://www.freedesktop.org/wiki/Software/libqmi/ + +Usage Example +~ + +QMI command to retrieve device mode +$ sudo qmicli -d /dev/mhi_\:02\:00.0_QMI --dms-get-model +[/dev/mhi_:02:00.0_QMI] Device model retrieved: +Model: 'FN980m' + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diagnostic +client using DIAG channel 4 (Host to device) and 5 (Device to Host). -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v12 5/5] selftest: mhi: Add support to test MHI LOOPBACK channel
Hi Shuah,
On 11/20/20 7:26 AM, Shuah Khan wrote:
On 11/16/20 3:46 PM, Hemant Kumar wrote:
Loopback test opens the MHI device file node and writes
a data buffer to it. MHI UCI kernel space driver copies
the data and sends it to MHI uplink (Tx) LOOPBACK channel.
MHI device loops back the same data to MHI downlink (Rx)
LOOPBACK channel. This data is read by test application
and compared against the data sent. Test passes if data
buffer matches between Tx and Rx. Test application performs
open(), poll(), write(), read() and close() file operations.
Signed-off-by: Hemant Kumar
---
Documentation/mhi/uci.rst | 32 +
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/drivers/.gitignore | 1 +
tools/testing/selftests/drivers/mhi/Makefile | 8 +
tools/testing/selftests/drivers/mhi/config | 2 +
.../testing/selftests/drivers/mhi/loopback_test.c | 802
+
6 files changed, 846 insertions(+)
create mode 100644 tools/testing/selftests/drivers/mhi/Makefile
create mode 100644 tools/testing/selftests/drivers/mhi/config
create mode 100644 tools/testing/selftests/drivers/mhi/loopback_test.c
diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst
index ce8740e..0a04afe 100644
--- a/Documentation/mhi/uci.rst
+++ b/Documentation/mhi/uci.rst
@@ -79,6 +79,38 @@ MHI client driver performs read operation, same
data gets looped back to MHI
host using LOOPBACK channel 1. LOOPBACK channel is used to verify
data path
and data integrity between MHI Host and MHI device.
Nice.
[..]
+
+enum debug_level {
+ DBG_LVL_VERBOSE,
+ DBG_LVL_INFO,
+ DBG_LVL_ERROR,
+};
+
+enum test_status {
+ TEST_STATUS_SUCCESS,
+ TEST_STATUS_ERROR,
+ TEST_STATUS_NO_DEV,
+};
+
Since you are running this test as part of kselftest, please use
ksft errors nd returns.
Are you suggesting to use following macros instead of test_status enum ?
#define KSFT_PASS 0
#define KSFT_FAIL 1
+struct lb_test_ctx {
+ char dev_node[256];
+ unsigned char *tx_buff;
+ unsigned char *rx_buff;
+ unsigned int rx_pkt_count;
+ unsigned int tx_pkt_count;
+ int iterations;
+ bool iter_complete;
+ bool comp_complete;
+ bool test_complete;
+ bool all_complete;
+ unsigned long buff_size;
+ long byte_recvd;
+ long byte_sent;
+};
+
+bool force_exit;
+char write_data = 'a';
+int completed_iterations;
+
+struct lb_test_ctx test_ctxt;
+enum debug_level msg_lvl;
+struct pollfd read_fd;
+struct pollfd write_fd;
+enum test_status mhi_test_return_value;
+enum test_status tx_status;
+enum test_status rx_status;
+enum test_status cmp_rxtx_status;
+
+#define test_log(test_msg_lvl, format, ...) do { \
+ if (test_msg_lvl >= msg_lvl) \
+ fprintf(stderr, format, ##__VA_ARGS__); \
+} while (0)
+
+static void loopback_test_sleep_ms(int ms)
+{
+ usleep(1000 * ms);
+}
+
Have you run this as part of "make kselftest" run. How does this
sleep work in that env.?
Looks like kselftest runs this test application by directly executing
the binary, but this test application requires a valid mhi device file
node as a required parameter. So considering that requirement, is this
test application qualifies to run using kselftest ? Without a valid
device file node test would fail. Is there an option to run this test as
standalone test which can only be run when a mhi device file node is
present ? Having said that i tested this driver by
directly executing it using the test binary which is compiled using
make loopback_test under mhi dir.
Are there any cases where this test can't run and have to - those
cases need to be skips.
Yes, as this test application can not run by itself it needs a valid mhi
device file node to write and test reads the same device node to get the
data back.
So test can not be run without having a MHI device connected over a
transport (in my testing MHI device is connected over PCIe). Could you
please suggest an option to use this test application as a standalone
test instead of being part of kselftest?
thanks,
-- Shuah
Thanks,
Hemant
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Re: [PATCH v12 5/5] selftest: mhi: Add support to test MHI LOOPBACK channel
Hi Mani, On 11/19/20 10:10 PM, Manivannan Sadhasivam wrote: On Mon, Nov 16, 2020 at 02:46:22PM -0800, Hemant Kumar wrote: Loopback test opens the MHI device file node and writes a data buffer to it. MHI UCI kernel space driver copies the data and sends it to MHI uplink (Tx) LOOPBACK channel. MHI device loops back the same data to MHI downlink (Rx) LOOPBACK channel. This data is read by test application and compared against the data sent. Test passes if data buffer matches between Tx and Rx. Test application performs open(), poll(), write(), read() and close() file operations. Signed-off-by: Hemant Kumar One nitpick below, with that addressed: Reviewed-by: Manivannan Sadhasivam [..] Effectively this functions does parse and run, so this should be called as, "loopback_test_parse_run" or pthread creation should be moved here. Done. -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v12 2/5] bus: mhi: core: Move MHI_MAX_MTU to external header file
Currently this macro is defined in internal MHI header as
a TRE length mask. Moving it to external header allows MHI
client drivers to set this upper bound for the transmit
buffer size.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/internal.h | 1 -
include/linux/mhi.h | 3 +++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 2df8de5..7d1f8bc 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -453,7 +453,6 @@ enum mhi_pm_state {
#define CMD_EL_PER_RING128
#define PRIMARY_CMD_RING 0
#define MHI_DEV_WAKE_DB127
-#define MHI_MAX_MTU0x
#define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1)
enum mhi_er_type {
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index a4d0f48..53bb41d 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -15,6 +15,9 @@
#include
#include
+/* MHI client drivers to set this upper bound for tx buffer */
+#define MHI_MAX_MTU 0x
+
#define MHI_MAX_OEM_PK_HASH_SEGMENTS 16
struct mhi_chan;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v12 5/5] selftest: mhi: Add support to test MHI LOOPBACK channel
Loopback test opens the MHI device file node and writes a data buffer to it. MHI UCI kernel space driver copies the data and sends it to MHI uplink (Tx) LOOPBACK channel. MHI device loops back the same data to MHI downlink (Rx) LOOPBACK channel. This data is read by test application and compared against the data sent. Test passes if data buffer matches between Tx and Rx. Test application performs open(), poll(), write(), read() and close() file operations. Signed-off-by: Hemant Kumar --- Documentation/mhi/uci.rst | 32 + tools/testing/selftests/Makefile | 1 + tools/testing/selftests/drivers/.gitignore | 1 + tools/testing/selftests/drivers/mhi/Makefile | 8 + tools/testing/selftests/drivers/mhi/config | 2 + .../testing/selftests/drivers/mhi/loopback_test.c | 802 + 6 files changed, 846 insertions(+) create mode 100644 tools/testing/selftests/drivers/mhi/Makefile create mode 100644 tools/testing/selftests/drivers/mhi/config create mode 100644 tools/testing/selftests/drivers/mhi/loopback_test.c diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst index ce8740e..0a04afe 100644 --- a/Documentation/mhi/uci.rst +++ b/Documentation/mhi/uci.rst @@ -79,6 +79,38 @@ MHI client driver performs read operation, same data gets looped back to MHI host using LOOPBACK channel 1. LOOPBACK channel is used to verify data path and data integrity between MHI Host and MHI device. +Loopback Test +~ + +Loopback test application is used to verify data integrity between MHI host and +MHI device over LOOPBACK channel. This also confirms that basic MHI data path +is working properly. Test performs write() to send tx buffer to MHI device file +node for LOOPBACK uplink channel. MHI LOOPBACK downlink channel loops back +transmit data to MHI Host. Test application receives data in receive buffer as +part of read(). It verifies if tx buffer matches rx buffer. Test application +performs poll() before making write() and read() system calls. Test passes if +match is found. + +Test is present under tools/testing/selftests/drivers/mhi. It is compiled using +following command in same dir:- + +make loopback_test + +Test is run using following command arguments:- + +loopback_test -c -b -l -i + + +Required argument: +-c : loopback chardev node + +Optional argument: +-b : transmit buffer size. If not present 1024 bytes size transmit buffer + is sent. +-i : Number of iterations to perform, If not present only one transmit buffer + is sent. +-l : Log level. If not present defaults to DBG_LVL_INFO. + Other Use Cases --- diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index d9c2835..084bc1e 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -10,6 +10,7 @@ TARGETS += core TARGETS += cpufreq TARGETS += cpu-hotplug TARGETS += drivers/dma-buf +TARGETS += drivers/mhi TARGETS += efivarfs TARGETS += exec TARGETS += filesystems diff --git a/tools/testing/selftests/drivers/.gitignore b/tools/testing/selftests/drivers/.gitignore index ca74f2e..e4806d5 100644 --- a/tools/testing/selftests/drivers/.gitignore +++ b/tools/testing/selftests/drivers/.gitignore @@ -1,2 +1,3 @@ # SPDX-License-Identifier: GPL-2.0-only /dma-buf/udmabuf +/mhi/loopback_test diff --git a/tools/testing/selftests/drivers/mhi/Makefile b/tools/testing/selftests/drivers/mhi/Makefile new file mode 100644 index 000..c06c925 --- /dev/null +++ b/tools/testing/selftests/drivers/mhi/Makefile @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0-only +CFLAGS += -I../../../../../usr/include/ -g -Wall + +LDLIBS = -lpthread +TEST_GEN_PROGS := loopback_test + +include ../../lib.mk + diff --git a/tools/testing/selftests/drivers/mhi/config b/tools/testing/selftests/drivers/mhi/config new file mode 100644 index 000..471dc92 --- /dev/null +++ b/tools/testing/selftests/drivers/mhi/config @@ -0,0 +1,2 @@ +CONFIG_MHI_BUS=y +CONFIG_MHi_UCI=y diff --git a/tools/testing/selftests/drivers/mhi/loopback_test.c b/tools/testing/selftests/drivers/mhi/loopback_test.c new file mode 100644 index 000..99b7712 --- /dev/null +++ b/tools/testing/selftests/drivers/mhi/loopback_test.c @@ -0,0 +1,802 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Loopback test application performs write() to send tx buffer to MHI device + * file node for LOOPBACK uplink channel. MHI LOOPBACK downlink channel loops + * back transmit data to MHI Host. Test application receives data in receive + * buffer as part of read(). It verifies if tx buffer matches rx buffer. Test + * application performs poll() before making write() and read() system + * calls. Test passes if match is found. + * + * Test is compiled using following command:- + * + * make loopback_test + * + * Test is run using following command arguments:- + * + * loopback_test -c -b -l -i + * + * + * Required argument: + * -c : loopback
[PATCH v12 3/5] docs: Add documentation for userspace client interface
MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently Loopback MHI channel is supported by this driver. Signed-off-by: Hemant Kumar --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 86 + 2 files changed, 87 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..ce8740e --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,86 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + +UCI driver enables userspace clients to communicate to external MHI devices +like modem and WLAN. UCI driver probe creates standard character device file +nodes for userspace clients to perform open, read, write, poll and release file +operations. UCI device object represents UCI device file node which gets +instantiated as part of MHI UCI driver probe. UCI channel object represents +MHI uplink or downlink channel. + +Operations +== + +open + + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read + + +When data transfer is completed on downlink channel, transfer ring element +buffer is copied to pending list. Reader is unblocked and data is copied to +userspace buffer. Transfer ring element buffer is queued back to downlink +channel transfer ring. + +write +- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll + + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. Returns EPOLLERR when UCI driver is removed. + +release +--- + +Decrements UCI device reference count and UCI channel reference count upon last +release(). UCI channel clean up is performed. MHI channel moves to disable +state and inbound buffers are freed. + +Usage += + +Device file node is created with format:- + +/dev/mhi__ + +controller_name is the name of underlying bus used to transfer data. mhi_device +name is the name of the MHI channel being used by MHI client in userspace to +send or receive data using MHI protocol. + +There is a separate character device file node created for each channel +specified in MHI device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +LOOPBACK Channel + + +Userspace MHI client using LOOPBACK channel opens device file node. As part of +open operation transfer ring elements are queued to transfer ring of LOOPBACK +channel 1 and channel doorbell is rung. When userspace MHI client performs write +operation on device node, data buffer gets queued as part of transfer ring +element to transfer ring of LOOPBACK channel 0. MHI Core driver rings the +channel doorbell for MHI device to move data over underlying bus. When userspace +MHI client driver performs read operation, same data gets looped back to MHI +host using LOOPBACK channel 1. LOOPBACK channel is used to verify data path +and data integrity between MHI Host and MHI device. + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diagnostic +client using DIAG channel 4 (Host to device) and 5 (Device to Host). -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v12 1/5] bus: mhi: core: Add helper API to return number of free TREs
Introduce mhi_get_free_desc_count() API to return number
of TREs available to queue buffer. MHI clients can use this
API to know before hand if ring is full without calling queue
API.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/main.c | 12
include/linux/mhi.h | 9 +
2 files changed, 21 insertions(+)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index f953e2a..6158720 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -260,6 +260,18 @@ int mhi_destroy_device(struct device *dev, void *data)
return 0;
}
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ struct mhi_chan *mhi_chan = (dir == DMA_TO_DEVICE) ?
+ mhi_dev->ul_chan : mhi_dev->dl_chan;
+ struct mhi_ring *tre_ring = _chan->tre_ring;
+
+ return get_nr_avail_ring_elements(mhi_cntrl, tre_ring);
+}
+EXPORT_SYMBOL_GPL(mhi_get_free_desc_count);
+
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
{
struct mhi_driver *mhi_drv;
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index 52b3c60..a4d0f48 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -597,6 +597,15 @@ void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl,
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason);
/**
+ * mhi_get_free_desc_count - Get transfer ring length
+ * Get # of TD available to queue buffers
+ * @mhi_dev: Device associated with the channels
+ * @dir: Direction of the channel
+ */
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir);
+
+/**
* mhi_prepare_for_power_up - Do pre-initialization before power up.
*This is optional, call this before power up if
*the controller does not want bus framework to
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v12 0/5] userspace MHI client interface driver
This patch series adds support for UCI driver. UCI driver enables userspace clients to communicate to external MHI devices like modem and WLAN. UCI driver probe creates standard character device file nodes for userspace clients to perform open, read, write, poll and release file operations. These file operations call MHI core layer APIs to perform data transfer using MHI bus to communicate with MHI device. It also adds a loopback test application to verify the UCI LOOPBACK channel. Patch is tested using arm64 based platform. V12: - Added loopback test driver under selftest/drivers/mhi. Updated kernel documentation for the usage of the loopback test application. - Addressed review comments for renaming variable names, updated inline comments and removed two redundant dev_dbg. V11: - Fixed review comments for UCI documentation by expanding TLAs and rewording some sentences. V10: - Replaced mutex_lock with mutex_lock_interruptible in read() and write() file ops call back. V9: - Renamed dl_lock to dl_pending _lock and pending list to dl_pending for clarity. - Used read lock to protect cur_buf. - Change transfer status check logic and only consider 0 and -EOVERFLOW as only success. - Added __int to module init function. - Print channel name instead of minor number upon successful probe. V8: - Fixed kernel test robot compilation error by changing %lu to %zu for size_t. - Replaced uci with UCI in Kconfig, commit text, and comments in driver code. - Fixed minor style related comments. V7: - Decoupled uci device and uci channel objects. uci device is associated with device file node. uci channel is associated with MHI channels. uci device refers to uci channel to perform MHI channel operations for device file operations like read() and write(). uci device increments its reference count for every open(). uci device calls mhi_uci_dev_start_chan() to start the MHI channel. uci channel object is tracking number of times MHI channel is referred. This allows to keep the MHI channel in start state until last release() is called. After that uci channel reference count goes to 0 and uci channel clean up is performed which stops the MHI channel. After the last call to release() if driver is removed uci reference count becomes 0 and uci object is cleaned up. - Use separate uci channel read and write lock to fine grain locking between reader and writer. - Use uci device lock to synchronize open, release and driver remove. - Optimize for downlink only or uplink only UCI device. V6: - Moved uci.c to mhi directory. - Updated Kconfig to add module information. - Updated Makefile to rename uci object file name as mhi_uci - Removed kref for open count V5: - Removed mhi_uci_drv structure. - Used idr instead of creating global list of uci devices. - Used kref instead of local ref counting for uci device and open count. - Removed unlikely macro. V4: - Fix locking to protect proper struct members. - Updated documentation describing uci client driver use cases. - Fixed uci ref counting in mhi_uci_open for error case. - Addressed style related review comments. V3: Added documentation for MHI UCI driver. V2: - Added mutex lock to prevent multiple readers to access same - mhi buffer which can result into use after free. Hemant Kumar (5): bus: mhi: core: Add helper API to return number of free TREs bus: mhi: core: Move MHI_MAX_MTU to external header file docs: Add documentation for userspace client interface bus: mhi: Add userspace client interface driver selftest: mhi: Add support to test MHI LOOPBACK channel Documentation/mhi/index.rst| 1 + Documentation/mhi/uci.rst | 109 +++ drivers/bus/mhi/Kconfig| 13 + drivers/bus/mhi/Makefile | 3 + drivers/bus/mhi/core/internal.h| 1 - drivers/bus/mhi/core/main.c| 12 + drivers/bus/mhi/uci.c | 667 + include/linux/mhi.h| 12 + tools/testing/selftests/Makefile | 1 + tools/testing/selftests/drivers/.gitignore | 1 + tools/testing/selftests/drivers/mhi/Makefile | 8 + tools/testing/selftests/drivers/mhi/config | 2 + .../testing/selftests/drivers/mhi/loopback_test.c | 789 + 13 files changed, 1618 insertions(+), 1 deletion(-) create mode 100644 Documentation/mhi/uci.rst create mode 100644 drivers/bus/mhi/uci.c create mode 100644 tools/testing/selftests/drivers/mhi/Makefile create mode 100644 tools/testing/selftests/drivers/mhi/config create mode 100644 tools/testing/selftests/drivers/mhi/loopback_test.c -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v12 4/5] bus: mhi: Add userspace client interface driver
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
/dev/mhi__
Currently it supports LOOPBACK channel.
Signed-off-by: Hemant Kumar
---
drivers/bus/mhi/Kconfig | 13 +
drivers/bus/mhi/Makefile | 3 +
drivers/bus/mhi/uci.c| 667 +++
3 files changed, 683 insertions(+)
create mode 100644 drivers/bus/mhi/uci.c
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index da5cd0c..5194e8e 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -29,3 +29,16 @@ config MHI_BUS_PCI_GENERIC
This driver provides MHI PCI controller driver for devices such as
Qualcomm SDX55 based PCIe modems.
+config MHI_UCI
+ tristate "MHI UCI"
+ depends on MHI_BUS
+ help
+ MHI based Userspace Client Interface (UCI) driver is used for
+ transferring raw data between host and device using standard file
+ operations from userspace. Open, read, write, poll and close
+ operations are supported by this driver. Please check
+ mhi_uci_match_table for all supported channels that are exposed to
+ userspace.
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_uci.
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 0a2d778..69f2111 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -4,3 +4,6 @@ obj-y += core/
obj-$(CONFIG_MHI_BUS_PCI_GENERIC) += mhi_pci_generic.o
mhi_pci_generic-y += pci_generic.o
+# MHI client
+mhi_uci-y := uci.o
+obj-$(CONFIG_MHI_UCI) += mhi_uci.o
diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c
new file mode 100644
index 000..75b0831
--- /dev/null
+++ b/drivers/bus/mhi/uci.c
@@ -0,0 +1,667 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/
+
+#include
+#include
+#include
+#include
+#include
+
+#define MHI_DEVICE_NAME "mhi"
+#define MHI_UCI_DRIVER_NAME "mhi_uci"
+#define MHI_MAX_UCI_MINORS 128
+
+static DEFINE_IDR(uci_idr);
+static DEFINE_MUTEX(uci_drv_mutex);
+static struct class *uci_dev_class;
+static int uci_dev_major;
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_pending_lock: spin lock for dl_pending list
+ * @dl_pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
+
+/**
+ * struct uci_buf - UCI buffer
+ * @data: data buffer
+ * @len: length of data buffer
+ * @node: list node of the UCI buffer
+ */
+struct uci_buf {
+ void *data;
+ size_t len;
+ struct list_head node;
+};
+
+/**
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Flag to track the state of the UCI device
+ * @lock: mutex lock to manage uchan object
+ * @ref_count: uci_dev reference count
+ */
+struct uci_dev {
+ unsigned int minor;
+ struct mhi_device *mhi_dev;
+ struct uci_chan *uchan;
+ size_t mtu;
+ bool enabled;
+
+ /* synchronize open, release and driver remove */
+ struct mutex lock;
+ struct kref ref_count;
+};
+
+static void mhi_uci_dev_chan_release(struct kref *ref)
+{
+ struct uci_buf *buf_itr, *tmp;
+ struct uci_chan *uchan =
+ container_of(ref, struct uci_chan, ref_count);
+
+ if (uchan->udev->enabled)
+ mhi
Re: [PATCH v2] bus: mhi: core: Fix null pointer access when parsing MHI configuration
On 11/2/20 4:27 AM, carl@quectel.com wrote:
From: "carl.yin"
Functions parse_ev_cfg() and parse_ch_cfg() access mhi_cntrl->mhi_dev
before it is set in function mhi_register_controller(),
use cntrl_dev instead of mhi_dev.
Fixes: 0cbf260820fa ("bus: mhi: core: Add support for registering MHI
controllers")
Signed-off-by: carl.yin
Reviewed-by: Bhaumik Bhatt
Reviewed-by: Hemant Kumar
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Re: [PATCH v11 4/4] bus: mhi: Add userspace client interface driver
Hi Mani,
On 10/30/20 3:34 AM, Manivannan Sadhasivam wrote:
Hi Hemant,
On Thu, Oct 29, 2020 at 07:45:46PM -0700, Hemant Kumar wrote:
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
/dev/mhi__
Currently it supports LOOPBACK channel.
Signed-off-by: Hemant Kumar
Thanks for continuously updating the series based on reviews, now the locking
part looks a _lot_ cleaner than it used to be. I just have one query (inline)
regarding the usage of refcount for uci_chan and uci_dev. Once you fix that,
I think this is good to go in.
Thanks for reviewing my changes.
[..]
+#define DEVICE_NAME "mhi"
+#define MHI_UCI_DRIVER_NAME "mhi_uci"
+#define MAX_UCI_MINORS 128
Prefix MHI for these.
Done.
+
+static DEFINE_IDR(uci_idr);
+static DEFINE_MUTEX(uci_drv_mutex);
+static struct class *uci_dev_class;
+static int uci_dev_major;
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_pending_lock: spin lock for dl_pending list
+ * @dl_pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
I asked you to move these comments to Kdoc in previous iteration.
There are multiple revisions of UCI pushed after i responded on this
one. On V7 i responded to your comment :)
"This was added because checkpatch --strict required to add a comment
when lock is added to struct, after adding inline comment, checkpatch
error was gone."
i was sticking to --strict option. Considering it is best to address
what --strict is complaining for.
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
I'm now thinking that instead of having two reference counts for uci_chan and
uci_dev, why can't you club them together and just use uci_dev's refcount to
handle the channel management also.
For instance in uci_open, you are incrementing the refcount for uci_dev before
starting the channel and then doing the same for uci_chan in
mhi_uci_dev_start_chan(). So why can't you just use a single refcount once the
mhi_uci_dev_start_chan() succeeds? The UCI device is useless without a channel,
isn't it?
Main idea is to have the uci driver probed (uci device object is
instantiated) but it is possible that device node is not opened or if it
was opened before and release() was called after that. So UCI channel is
not active but device node would continue to exist. Which can be opened
again and channel would move to start state. So we dont want to couple
mhi driver probe with starting of channels. We start channels only when
it is really needed. This would allow MHI device to go to lower power
state when channels are disabled.
[..]
+
+static int mhi_queue_inbound(struct uci_dev *udev)
+{
+ struct mhi_device *mhi_dev = udev->mhi_dev;
+ struct device *dev = _dev->dev;
+ int nr_trbs, i, ret = -EIO;
s/nr_trbs/nr_desc
Done.
+ size_t dl_buf_size;
+ void *buf;
+ struct uci_buf *ubuf;
+
+ /* dont queue if dl channel is not supported */
+ if (!udev->mhi_dev->dl_chan)
+ return 0;
Not returning an error?
Here we dont need to return error because when open is called it would
call this function and if dl_chan is not supported we still want to
return success for a uci device which only supports UL channel.
Keeping this check inside function looks clean so i am not adding this
check in open().
[..]
+static __poll_t mhi_uci_poll(struct file *file, poll_table *wait)
+{
+ struct uci_dev *udev = file->private_data;
+ struct mhi_device *mhi_dev = udev->mhi_dev;
+ struct device *dev = _dev-&g
Re: [PATCH v11 4/4] bus: mhi: Add userspace client interface driver
Hi Randy, On 10/29/20 10:48 PM, Randy Dunlap wrote: On 10/29/20 7:45 PM, Hemant Kumar wrote: diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig index e841c10..476cc55 100644 --- a/drivers/bus/mhi/Kconfig +++ b/drivers/bus/mhi/Kconfig @@ -20,3 +20,16 @@ config MHI_BUS_DEBUG Enable debugfs support for use with the MHI transport. Allows reading and/or modifying some values within the MHI controller for debug and test purposes. + +config MHI_UCI + tristate "MHI UCI" + depends on MHI_BUS + help + MHI based Userspace Client Interface (UCI) driver is used for MHI-based + transferring raw data between host and device using standard file + operations from userspace. Open, read, write, and close operations + are supported by this driver. Please check mhi_uci_match_table for also poll according to the documentation. good catch, will add in next patch set. + all supported channels that are exposed to userspace. + + To compile this driver as a module, choose M here: the module will be + called mhi_uci. Thanks, Hemant -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v11 3/4] docs: Add documentation for userspace client interface
MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently Loopback MHI channel is supported by this driver. Signed-off-by: Hemant Kumar --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 84 + 2 files changed, 85 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..4f706cb --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,84 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + +UCI driver enables userspace clients to communicate to external MHI devices +like modem and WLAN. UCI driver probe creates standard character device file +nodes for userspace clients to perform open, read, write, poll and release file +operations. + +Operations +== + +open + + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read + + +When data transfer is completed on downlink channel, transfer ring element +buffer is copied to pending list. Reader is unblocked and data is copied to +userspace buffer. Transfer ring element buffer is queued back to downlink +channel transfer ring. + +write +- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll + + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. Returns EPOLLERR when UCI driver is removed. + +release +--- + +Decrements UCI device reference count and UCI channel reference count upon last +release(). UCI channel clean up is performed. MHI channel moves to disable +state and inbound buffers are freed. + +Usage += + +Device file node is created with format:- + +/dev/mhi__ + +controller_name is the name of underlying bus used to transfer data. mhi_device +name is the name of the MHI channel being used by MHI client in userspace to +send or receive data using MHI protocol. + +There is a separate character device file node created for each channel +specified in MHI device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +LOOPBACK Channel + + +Userspace MHI client using LOOPBACK channel opens device file node. As part of +open operation transfer ring elements are queued to transfer ring of LOOPBACK +channel 1 and channel doorbell is rung. When userspace MHI client performs write +operation on device node, data buffer gets queued as part of transfer ring +element to transfer ring of LOOPBACK channel 0. MHI Core driver rings the +channel doorbell for MHI device to move data over underlying bus. When userspace +MHI client driver performs read operation, same data gets looped back to MHI +host using LOOPBACK channel 1. LOOPBACK channel is used to verify data path +and data integrity between MHI Host and MHI device. + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diagnostic +client using DIAG channel 4 (Host to device) and 5 (Device to Host). -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v11 4/4] bus: mhi: Add userspace client interface driver
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
/dev/mhi__
Currently it supports LOOPBACK channel.
Signed-off-by: Hemant Kumar
---
drivers/bus/mhi/Kconfig | 13 +
drivers/bus/mhi/Makefile | 4 +
drivers/bus/mhi/uci.c| 662 +++
3 files changed, 679 insertions(+)
create mode 100644 drivers/bus/mhi/uci.c
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index e841c10..476cc55 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -20,3 +20,16 @@ config MHI_BUS_DEBUG
Enable debugfs support for use with the MHI transport. Allows
reading and/or modifying some values within the MHI controller
for debug and test purposes.
+
+config MHI_UCI
+ tristate "MHI UCI"
+ depends on MHI_BUS
+ help
+ MHI based Userspace Client Interface (UCI) driver is used for
+ transferring raw data between host and device using standard file
+ operations from userspace. Open, read, write, and close operations
+ are supported by this driver. Please check mhi_uci_match_table for
+ all supported channels that are exposed to userspace.
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_uci.
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 19e6443..80feefb 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -1,2 +1,6 @@
# core layer
obj-y += core/
+
+# MHI client
+mhi_uci-y := uci.o
+obj-$(CONFIG_MHI_UCI) += mhi_uci.o
diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c
new file mode 100644
index 000..ea73c08
--- /dev/null
+++ b/drivers/bus/mhi/uci.c
@@ -0,0 +1,662 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/
+
+#include
+#include
+#include
+#include
+#include
+
+#define DEVICE_NAME "mhi"
+#define MHI_UCI_DRIVER_NAME "mhi_uci"
+#define MAX_UCI_MINORS 128
+
+static DEFINE_IDR(uci_idr);
+static DEFINE_MUTEX(uci_drv_mutex);
+static struct class *uci_dev_class;
+static int uci_dev_major;
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_pending_lock: spin lock for dl_pending list
+ * @dl_pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
+
+/**
+ * struct uci_buf - UCI buffer
+ * @data: data buffer
+ * @len: length of data buffer
+ * @node: list node of the UCI buffer
+ */
+struct uci_buf {
+ void *data;
+ size_t len;
+ struct list_head node;
+};
+
+/**
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Flag to track the state of the UCI device
+ * @lock: mutex lock to manage uchan object
+ * @ref_count: uci_dev reference count
+ */
+struct uci_dev {
+ unsigned int minor;
+ struct mhi_device *mhi_dev;
+ struct uci_chan *uchan;
+ size_t mtu;
+ bool enabled;
+
+ /* synchronize open, release and driver remove */
+ struct mutex lock;
+ struct kref ref_count;
+};
+
+static void mhi_uci_dev_chan_release(struct kref *ref)
+{
+ struct uci_buf *buf_itr, *tmp;
+ struct uci_chan *uchan =
+ container_of(ref, struct uci_chan, ref_count);
+
+ if (uchan->udev->enabled)
+ mhi_unprepare_from_transfer(uchan->
[PATCH v11 0/4] userspace MHI client interface driver
This patch series adds support for UCI driver. UCI driver enables userspace clients to communicate to external MHI devices like modem and WLAN. UCI driver probe creates standard character device file nodes for userspace clients to perform open, read, write, poll and release file operations. These file operations call MHI core layer APIs to perform data transfer using MHI bus to communicate with MHI device. Patch is tested using arm64 based platform. V11: - Fixed review comments for UCI documentation by expanding TLAs and rewording some sentences. V10: - Replaced mutex_lock with mutex_lock_interruptible in read() and write() file ops call back. V9: - Renamed dl_lock to dl_pending _lock and pending list to dl_pending for clarity. - Used read lock to protect cur_buf. - Change transfer status check logic and only consider 0 and -EOVERFLOW as only success. - Added __int to module init function. - Print channel name instead of minor number upon successful probe. V8: - Fixed kernel test robot compilation error by changing %lu to %zu for size_t. - Replaced uci with UCI in Kconfig, commit text, and comments in driver code. - Fixed minor style related comments. V7: - Decoupled uci device and uci channel objects. uci device is associated with device file node. uci channel is associated with MHI channels. uci device refers to uci channel to perform MHI channel operations for device file operations like read() and write(). uci device increments its reference count for every open(). uci device calls mhi_uci_dev_start_chan() to start the MHI channel. uci channel object is tracking number of times MHI channel is referred. This allows to keep the MHI channel in start state until last release() is called. After that uci channel reference count goes to 0 and uci channel clean up is performed which stops the MHI channel. After the last call to release() if driver is removed uci reference count becomes 0 and uci object is cleaned up. - Use separate uci channel read and write lock to fine grain locking between reader and writer. - Use uci device lock to synchronize open, release and driver remove. - Optimize for downlink only or uplink only UCI device. V6: - Moved uci.c to mhi directory. - Updated Kconfig to add module information. - Updated Makefile to rename uci object file name as mhi_uci - Removed kref for open count V5: - Removed mhi_uci_drv structure. - Used idr instead of creating global list of uci devices. - Used kref instead of local ref counting for uci device and open count. - Removed unlikely macro. V4: - Fix locking to protect proper struct members. - Updated documentation describing uci client driver use cases. - Fixed uci ref counting in mhi_uci_open for error case. - Addressed style related review comments. V3: Added documentation for MHI UCI driver. V2: - Added mutex lock to prevent multiple readers to access same - mhi buffer which can result into use after free. Hemant Kumar (4): bus: mhi: core: Add helper API to return number of free TREs bus: mhi: core: Move MHI_MAX_MTU to external header file docs: Add documentation for userspace client interface bus: mhi: Add userspace client interface driver Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 84 + drivers/bus/mhi/Kconfig | 13 + drivers/bus/mhi/Makefile| 4 + drivers/bus/mhi/core/internal.h | 1 - drivers/bus/mhi/core/main.c | 12 + drivers/bus/mhi/uci.c | 662 include/linux/mhi.h | 12 + 8 files changed, 788 insertions(+), 1 deletion(-) create mode 100644 Documentation/mhi/uci.rst create mode 100644 drivers/bus/mhi/uci.c -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v11 2/4] bus: mhi: core: Move MHI_MAX_MTU to external header file
Currently this macro is defined in internal MHI header as
a TRE length mask. Moving it to external header allows MHI
client drivers to set this upper bound for the transmit
buffer size.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/internal.h | 1 -
include/linux/mhi.h | 3 +++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 7989269..4abf0cf 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -453,7 +453,6 @@ enum mhi_pm_state {
#define CMD_EL_PER_RING128
#define PRIMARY_CMD_RING 0
#define MHI_DEV_WAKE_DB127
-#define MHI_MAX_MTU0x
#define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1)
enum mhi_er_type {
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index 7829b1d..6e1122c 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -15,6 +15,9 @@
#include
#include
+/* MHI client drivers to set this upper bound for tx buffer */
+#define MHI_MAX_MTU 0x
+
#define MHI_MAX_OEM_PK_HASH_SEGMENTS 16
struct mhi_chan;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v11 1/4] bus: mhi: core: Add helper API to return number of free TREs
Introduce mhi_get_free_desc_count() API to return number
of TREs available to queue buffer. MHI clients can use this
API to know before hand if ring is full without calling queue
API.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/main.c | 12
include/linux/mhi.h | 9 +
2 files changed, 21 insertions(+)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 2cff5dd..3950792 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -258,6 +258,18 @@ int mhi_destroy_device(struct device *dev, void *data)
return 0;
}
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ struct mhi_chan *mhi_chan = (dir == DMA_TO_DEVICE) ?
+ mhi_dev->ul_chan : mhi_dev->dl_chan;
+ struct mhi_ring *tre_ring = _chan->tre_ring;
+
+ return get_nr_avail_ring_elements(mhi_cntrl, tre_ring);
+}
+EXPORT_SYMBOL_GPL(mhi_get_free_desc_count);
+
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
{
struct mhi_driver *mhi_drv;
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index d4841e5..7829b1d 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -597,6 +597,15 @@ void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl,
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason);
/**
+ * mhi_get_free_desc_count - Get transfer ring length
+ * Get # of TD available to queue buffers
+ * @mhi_dev: Device associated with the channels
+ * @dir: Direction of the channel
+ */
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir);
+
+/**
* mhi_prepare_for_power_up - Do pre-initialization before power up.
*This is optional, call this before power up if
*the controller does not want bus framework to
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Re: [PATCH v10 3/4] docs: Add documentation for userspace client interface
Hi Randy, On 10/29/20 2:51 PM, Randy Dunlap wrote: Hi, On 10/29/20 2:40 PM, Hemant Kumar wrote: MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently Loopback MHI channel is supported by this driver. Signed-off-by: Hemant Kumar --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 83 + 2 files changed, 84 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..fe901c4 --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,83 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + Lots of TLAs. + +read + + +When data transfer is completed on downlink channel, TRE buffer is copied to +pending list. Reader is unblocked and data is copied to userspace buffer. TRE +buffer is queued back to downlink channel transfer ring. What is TRE? Transfer Ring Element i will add that in small bracket inline. + +Usage += + +Device file node is created with format:- + +/dev/mhi__ + +controller_name is the name of underlying bus used to transfer data. mhi_device +name is the name of the MHI channel being used by MHI client in userspace to +send or receive data using MHI protocol. + +There is a separate character device file node created for each channel +specified in mhi device id table. MHI channels are statically defined by MHI MHI unless it is a variable name, like below: mhi_device_id Done. +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diag client diagnostic client Done. +using DIAG channel 4 (Host to device) and 5 (Device to Host). thanks. Thanks for reviewing it. Let me fix it and re-upload. Thanks, Hemant -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v10 1/4] bus: mhi: core: Add helper API to return number of free TREs
Introduce mhi_get_free_desc_count() API to return number
of TREs available to queue buffer. MHI clients can use this
API to know before hand if ring is full without calling queue
API.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/main.c | 12
include/linux/mhi.h | 9 +
2 files changed, 21 insertions(+)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 2cff5dd..3950792 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -258,6 +258,18 @@ int mhi_destroy_device(struct device *dev, void *data)
return 0;
}
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ struct mhi_chan *mhi_chan = (dir == DMA_TO_DEVICE) ?
+ mhi_dev->ul_chan : mhi_dev->dl_chan;
+ struct mhi_ring *tre_ring = _chan->tre_ring;
+
+ return get_nr_avail_ring_elements(mhi_cntrl, tre_ring);
+}
+EXPORT_SYMBOL_GPL(mhi_get_free_desc_count);
+
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
{
struct mhi_driver *mhi_drv;
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index d4841e5..7829b1d 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -597,6 +597,15 @@ void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl,
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason);
/**
+ * mhi_get_free_desc_count - Get transfer ring length
+ * Get # of TD available to queue buffers
+ * @mhi_dev: Device associated with the channels
+ * @dir: Direction of the channel
+ */
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir);
+
+/**
* mhi_prepare_for_power_up - Do pre-initialization before power up.
*This is optional, call this before power up if
*the controller does not want bus framework to
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v10 3/4] docs: Add documentation for userspace client interface
MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently Loopback MHI channel is supported by this driver. Signed-off-by: Hemant Kumar --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 83 + 2 files changed, 84 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..fe901c4 --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,83 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + +UCI driver enables userspace clients to communicate to external MHI devices +like modem and WLAN. UCI driver probe creates standard character device file +nodes for userspace clients to perform open, read, write, poll and release file +operations. + +Operations +== + +open + + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read + + +When data transfer is completed on downlink channel, TRE buffer is copied to +pending list. Reader is unblocked and data is copied to userspace buffer. TRE +buffer is queued back to downlink channel transfer ring. + +write +- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll + + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. Returns EPOLLERR when UCI driver is removed. MHI channels +move to disabled state upon driver remove. + +release +--- + +Decrements UCI device reference count and UCI channel reference count upon last +release(). UCI channel clean up is performed. MHI channel moves to disabled +state and inbound buffers are freed. + +Usage += + +Device file node is created with format:- + +/dev/mhi__ + +controller_name is the name of underlying bus used to transfer data. mhi_device +name is the name of the MHI channel being used by MHI client in userspace to +send or receive data using MHI protocol. + +There is a separate character device file node created for each channel +specified in mhi device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +LOOPBACK Channel + + +Userspace MHI client using LOOPBACK channel opens device file node. As part of +open operation TREs to transfer ring of LOOPBACK channel 1 gets queued and channel +doorbell is rung. When userspace MHI client performs write operation on device node, +data buffer gets queued as a TRE to transfer ring of LOOPBACK channel 0. MHI Core +driver rings the channel doorbell for MHI device to move data over underlying bus. +When userspace MHI client driver performs read operation, same data gets looped back +to MHI host using LOOPBACK channel 1. LOOPBACK channel is used to verify data path +and data integrity between MHI Host and MHI device. + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diag client +using DIAG channel 4 (Host to device) and 5 (Device to Host). -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v10 2/4] bus: mhi: core: Move MHI_MAX_MTU to external header file
Currently this macro is defined in internal MHI header as
a TRE length mask. Moving it to external header allows MHI
client drivers to set this upper bound for the transmit
buffer size.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/internal.h | 1 -
include/linux/mhi.h | 3 +++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 7989269..4abf0cf 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -453,7 +453,6 @@ enum mhi_pm_state {
#define CMD_EL_PER_RING128
#define PRIMARY_CMD_RING 0
#define MHI_DEV_WAKE_DB127
-#define MHI_MAX_MTU0x
#define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1)
enum mhi_er_type {
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index 7829b1d..6e1122c 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -15,6 +15,9 @@
#include
#include
+/* MHI client drivers to set this upper bound for tx buffer */
+#define MHI_MAX_MTU 0x
+
#define MHI_MAX_OEM_PK_HASH_SEGMENTS 16
struct mhi_chan;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v10 4/4] bus: mhi: Add userspace client interface driver
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
/dev/mhi__
Currently it supports LOOPBACK channel.
Signed-off-by: Hemant Kumar
---
drivers/bus/mhi/Kconfig | 13 +
drivers/bus/mhi/Makefile | 4 +
drivers/bus/mhi/uci.c| 662 +++
3 files changed, 679 insertions(+)
create mode 100644 drivers/bus/mhi/uci.c
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index e841c10..476cc55 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -20,3 +20,16 @@ config MHI_BUS_DEBUG
Enable debugfs support for use with the MHI transport. Allows
reading and/or modifying some values within the MHI controller
for debug and test purposes.
+
+config MHI_UCI
+ tristate "MHI UCI"
+ depends on MHI_BUS
+ help
+ MHI based Userspace Client Interface (UCI) driver is used for
+ transferring raw data between host and device using standard file
+ operations from userspace. Open, read, write, and close operations
+ are supported by this driver. Please check mhi_uci_match_table for
+ all supported channels that are exposed to userspace.
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_uci.
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 19e6443..80feefb 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -1,2 +1,6 @@
# core layer
obj-y += core/
+
+# MHI client
+mhi_uci-y := uci.o
+obj-$(CONFIG_MHI_UCI) += mhi_uci.o
diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c
new file mode 100644
index 000..ea73c08
--- /dev/null
+++ b/drivers/bus/mhi/uci.c
@@ -0,0 +1,662 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/
+
+#include
+#include
+#include
+#include
+#include
+
+#define DEVICE_NAME "mhi"
+#define MHI_UCI_DRIVER_NAME "mhi_uci"
+#define MAX_UCI_MINORS 128
+
+static DEFINE_IDR(uci_idr);
+static DEFINE_MUTEX(uci_drv_mutex);
+static struct class *uci_dev_class;
+static int uci_dev_major;
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_pending_lock: spin lock for dl_pending list
+ * @dl_pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
+
+/**
+ * struct uci_buf - UCI buffer
+ * @data: data buffer
+ * @len: length of data buffer
+ * @node: list node of the UCI buffer
+ */
+struct uci_buf {
+ void *data;
+ size_t len;
+ struct list_head node;
+};
+
+/**
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Flag to track the state of the UCI device
+ * @lock: mutex lock to manage uchan object
+ * @ref_count: uci_dev reference count
+ */
+struct uci_dev {
+ unsigned int minor;
+ struct mhi_device *mhi_dev;
+ struct uci_chan *uchan;
+ size_t mtu;
+ bool enabled;
+
+ /* synchronize open, release and driver remove */
+ struct mutex lock;
+ struct kref ref_count;
+};
+
+static void mhi_uci_dev_chan_release(struct kref *ref)
+{
+ struct uci_buf *buf_itr, *tmp;
+ struct uci_chan *uchan =
+ container_of(ref, struct uci_chan, ref_count);
+
+ if (uchan->udev->enabled)
+ mhi_unprepare_from_transfer(uchan->
[PATCH v10 0/4] userspace MHI client interface driver
This patch series adds support for UCI driver. UCI driver enables userspace clients to communicate to external MHI devices like modem and WLAN. UCI driver probe creates standard character device file nodes for userspace clients to perform open, read, write, poll and release file operations. These file operations call MHI core layer APIs to perform data transfer using MHI bus to communicate with MHI device. Patch is tested using arm64 based platform. V10: - Replaced mutex_lock with mutex_lock_interruptible in read() and write() file ops call back. V9: - Renamed dl_lock to dl_pending _lock and pending list to dl_pending for clarity. - Used read lock to protect cur_buf. - Change transfer status check logic and only consider 0 and -EOVERFLOW as only success. - Added __int to module init function. - Print channel name instead of minor number upon successful probe. V8: - Fixed kernel test robot compilation error by changing %lu to %zu for size_t. - Replaced uci with UCI in Kconfig, commit text, and comments in driver code. - Fixed minor style related comments. V7: - Decoupled uci device and uci channel objects. uci device is associated with device file node. uci channel is associated with MHI channels. uci device refers to uci channel to perform MHI channel operations for device file operations like read() and write(). uci device increments its reference count for every open(). uci device calls mhi_uci_dev_start_chan() to start the MHI channel. uci channel object is tracking number of times MHI channel is referred. This allows to keep the MHI channel in start state until last release() is called. After that uci channel reference count goes to 0 and uci channel clean up is performed which stops the MHI channel. After the last call to release() if driver is removed uci reference count becomes 0 and uci object is cleaned up. - Use separate uci channel read and write lock to fine grain locking between reader and writer. - Use uci device lock to synchronize open, release and driver remove. - Optimize for downlink only or uplink only UCI device. V6: - Moved uci.c to mhi directory. - Updated Kconfig to add module information. - Updated Makefile to rename uci object file name as mhi_uci - Removed kref for open count V5: - Removed mhi_uci_drv structure. - Used idr instead of creating global list of uci devices. - Used kref instead of local ref counting for uci device and open count. - Removed unlikely macro. V4: - Fix locking to protect proper struct members. - Updated documentation describing uci client driver use cases. - Fixed uci ref counting in mhi_uci_open for error case. - Addressed style related review comments. V3: Added documentation for MHI UCI driver. V2: - Added mutex lock to prevent multiple readers to access same - mhi buffer which can result into use after free. Hemant Kumar (4): bus: mhi: core: Add helper API to return number of free TREs bus: mhi: core: Move MHI_MAX_MTU to external header file docs: Add documentation for userspace client interface bus: mhi: Add userspace client interface driver Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 83 + drivers/bus/mhi/Kconfig | 13 + drivers/bus/mhi/Makefile| 4 + drivers/bus/mhi/core/internal.h | 1 - drivers/bus/mhi/core/main.c | 12 + drivers/bus/mhi/uci.c | 662 include/linux/mhi.h | 12 + 8 files changed, 787 insertions(+), 1 deletion(-) create mode 100644 Documentation/mhi/uci.rst create mode 100644 drivers/bus/mhi/uci.c -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH] bus: mhi: core: Add support MHI EE FP for download firmware
Hi Jeff,
On 10/27/20 8:11 AM, Jeffrey Hugo wrote:
On 10/27/2020 3:43 AM, carl@quectel.com wrote:
From: "carl.yin"
MHI wwan modems support download firmware to nand or emmc
by firehose protocol, process as next:
1. wwan modem normal bootup and enter EE AMSS, create mhi DIAG chan
device
2. send EDL cmd via DIAG chan, then modem enter EE EDL
3. boot.c download 'firehose/prog_firehose_sdx55.mbn' via BHI interface
4. modem enter EE FP, and create mhi EDL chan device
5. user space tool download FW to modem via EDL chan by firehose protocol
Signed-off-by: carl.yin
---
drivers/bus/mhi/core/boot.c | 4 +++-
drivers/bus/mhi/core/init.c | 2 ++
drivers/bus/mhi/core/internal.h | 1 +
drivers/bus/mhi/core/main.c | 3 +++
drivers/bus/mhi/core/pm.c | 16 +++-
include/linux/mhi.h | 4 +++-
6 files changed, 27 insertions(+), 3 deletions(-)
diff --git a/drivers/bus/mhi/core/boot.c b/drivers/bus/mhi/core/boot.c
index 24422f5..ab39ad6 100644
--- a/drivers/bus/mhi/core/boot.c
+++ b/drivers/bus/mhi/core/boot.c
@@ -460,8 +460,10 @@ void mhi_fw_load_handler(struct mhi_controller
*mhi_cntrl)
return;
}
- if (mhi_cntrl->ee == MHI_EE_EDL)
+ if (mhi_cntrl->ee == MHI_EE_EDL) {
+ mhi_ready_state_transition(mhi_cntrl);
return;
+ }
write_lock_irq(_cntrl->pm_lock);
mhi_cntrl->dev_state = MHI_STATE_RESET;
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index ac4aa5c..9c2c2f3 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -26,6 +26,7 @@ const char * const mhi_ee_str[MHI_EE_MAX] = {
[MHI_EE_WFW] = "WFW",
[MHI_EE_PTHRU] = "PASS THRU",
[MHI_EE_EDL] = "EDL",
+ [MHI_EE_FP] = "FP",
[MHI_EE_DISABLE_TRANSITION] = "DISABLE",
[MHI_EE_NOT_SUPPORTED] = "NOT SUPPORTED",
};
@@ -35,6 +36,7 @@ const char * const
dev_state_tran_str[DEV_ST_TRANSITION_MAX] = {
[DEV_ST_TRANSITION_READY] = "READY",
[DEV_ST_TRANSITION_SBL] = "SBL",
[DEV_ST_TRANSITION_MISSION_MODE] = "MISSION_MODE",
+ [DEV_ST_TRANSITION_FP] = "FP",
[DEV_ST_TRANSITION_SYS_ERR] = "SYS_ERR",
[DEV_ST_TRANSITION_DISABLE] = "DISABLE",
};
diff --git a/drivers/bus/mhi/core/internal.h
b/drivers/bus/mhi/core/internal.h
index 4abf0cf..6ae897a 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -386,6 +386,7 @@ enum dev_st_transition {
DEV_ST_TRANSITION_READY,
DEV_ST_TRANSITION_SBL,
DEV_ST_TRANSITION_MISSION_MODE,
+ DEV_ST_TRANSITION_FP,
DEV_ST_TRANSITION_SYS_ERR,
DEV_ST_TRANSITION_DISABLE,
DEV_ST_TRANSITION_MAX,
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 3950792..e307b58 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -782,6 +782,9 @@ int mhi_process_ctrl_ev_ring(struct mhi_controller
*mhi_cntrl,
case MHI_EE_SBL:
st = DEV_ST_TRANSITION_SBL;
break;
+ case MHI_EE_FP:
+ st = DEV_ST_TRANSITION_FP;
+ break;
case MHI_EE_WFW:
case MHI_EE_AMSS:
st = DEV_ST_TRANSITION_MISSION_MODE;
diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index 3de7b16..3c95a5d 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -563,7 +563,15 @@ static void mhi_pm_disable_transition(struct
mhi_controller *mhi_cntrl,
}
if (cur_state == MHI_PM_SYS_ERR_PROCESS) {
- mhi_ready_state_transition(mhi_cntrl);
+ if (mhi_get_exec_env(mhi_cntrl) == MHI_EE_EDL
+ && mhi_get_mhi_state(mhi_cntrl) == MHI_STATE_RESET) {
+ write_lock_irq(_cntrl->pm_lock);
+ cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_POR);
+ write_unlock_irq(_cntrl->pm_lock);
+ mhi_queue_state_transition(mhi_cntrl,
DEV_ST_TRANSITION_PBL);
+ } else {
+ mhi_ready_state_transition(mhi_cntrl);
+ }
} else {
/* Move to disable state */
write_lock_irq(_cntrl->pm_lock);
@@ -658,6 +666,12 @@ void mhi_pm_st_worker(struct work_struct *work)
case DEV_ST_TRANSITION_MISSION_MODE:
mhi_pm_mission_mode_transition(mhi_cntrl);
break;
+ case DEV_ST_TRANSITION_FP:
+ write_lock_irq(_cntrl->pm_lock);
+ mhi_cntrl->ee = MHI_EE_FP;
+ write_unlock_irq(_cntrl->pm_lock);
+ mhi_create_devices(mhi_cntrl);
+ break;
case DEV_ST_TRANSITION_READY:
mhi_ready_state_transition(mhi_cntrl);
break;
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index 6e1122c..4620af8 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -120,6 +120,7 @@ struct mhi_link_info {
* @MHI_EE_WFW: WLAN firmware mode
* @MHI_EE_PTHRU: Passthrough
* @MHI_EE_EDL: Embedded downloader
+ * @MHI_EE_FP,
Re: [PATCH] bus: mhi: core: Introduce sysfs ul chan id for mhi chan device
Hi Carl,
On 10/27/20 8:06 AM, Jeffrey Hugo wrote:
On 10/27/2020 3:43 AM, carl@quectel.com wrote:
From: "carl.yin"
User space software like ModemManager can identify the function
of the mhi chan device by ul_chan_id.
Signed-off-by: carl.yin
---
Documentation/ABI/stable/sysfs-bus-mhi | 10 ++
drivers/bus/mhi/core/init.c | 15 +++
2 files changed, 25 insertions(+)
diff --git a/Documentation/ABI/stable/sysfs-bus-mhi
b/Documentation/ABI/stable/sysfs-bus-mhi
index ecfe766..6d52768 100644
--- a/Documentation/ABI/stable/sysfs-bus-mhi
+++ b/Documentation/ABI/stable/sysfs-bus-mhi
@@ -19,3 +19,13 @@ Description: The file holds the OEM PK Hash
value of the endpoint device
read without having the device power on at least once, the file
will read all 0's.
Users: Any userspace application or clients interested in
device info.
+
+What: /sys/bus/mhi/devices/.../ul_chan_id
+Date: November 2020
+KernelVersion: 5.10
+Contact: Carl Yin
+Description: The file holds the uplink chan id of the mhi chan
device.
+ User space software like ModemManager can identify the
function of
+ the mhi chan device. If the mhi device is not a chan device,
+ eg mhi controller device, the file read -1.
+Users: Any userspace application or clients interested in
device info.
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index c6b43e9..ac4aa5c 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -105,9 +105,24 @@ static ssize_t oem_pk_hash_show(struct device *dev,
}
static DEVICE_ATTR_RO(oem_pk_hash);
+static ssize_t ul_chan_id_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct mhi_device *mhi_dev = to_mhi_device(dev);
+ int ul_chan_id = -1;
+
+ if (mhi_dev->ul_chan)
+ ul_chan_id = mhi_dev->ul_chan_id;
+
+ return snprintf(buf, PAGE_SIZE, "%d\n", ul_chan_id);
+}
+static DEVICE_ATTR_RO(ul_chan_id);
+
static struct attribute *mhi_dev_attrs[] = {
_attr_serial_number.attr,
_attr_oem_pk_hash.attr,
+ _attr_ul_chan_id.attr,
NULL,
};
ATTRIBUTE_GROUPS(mhi_dev);
NACK
Channel ID is a device specific detail. Userspace should be basing
decisions on the channel name.
I agree with Jeff, why do you need to know the channel id, if you need
to poll for any device node to get created you can try to open the
device node from user space and wait until the device gets opened.
Are you trying to wait for EDL channels to get started using UCI ?
Thanks,
Hemant
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Re: [PATCH v9 4/4] bus: mhi: Add userspace client interface driver
Hi Loic,
On 10/26/20 10:34 AM, Loic Poulain wrote:
Hi Hemant,
That looks better IMHO, just small comments on locking.
[..]
+static ssize_t mhi_uci_write(struct file *file,
+ const char __user *buf,
+ size_t count,
+ loff_t *offp)
+{
+ struct uci_dev *udev = file->private_data;
+ struct mhi_device *mhi_dev = udev->mhi_dev;
+ struct device *dev = _dev->dev;
+ struct uci_chan *uchan = udev->uchan;
+ size_t bytes_xfered = 0;
+ int ret, nr_avail = 0;
+
+ /* if ul channel is not supported return error */
+ if (!buf || !count || !mhi_dev->ul_chan)
+ return -EINVAL;
+
+ dev_dbg(dev, "%s: to xfer: %zu bytes\n", __func__, count);
+
+ mutex_lock(>write_lock);
Maybe mutex_lock_interruptible is more appropriate here (same in read fops).
i agree, will return -EINTR if mutex_lock_interruptible returns < 0.
[..]
+static ssize_t mhi_uci_read(struct file *file,
+ char __user *buf,
+ size_t count,
+ loff_t *ppos)
+{
+ struct uci_dev *udev = file->private_data;
+ struct mhi_device *mhi_dev = udev->mhi_dev;
+ struct uci_chan *uchan = udev->uchan;
+ struct device *dev = _dev->dev;
+ struct uci_buf *ubuf;
+ size_t rx_buf_size;
+ char *ptr;
+ size_t to_copy;
+ int ret = 0;
+
+ /* if dl channel is not supported return error */
+ if (!buf || !mhi_dev->dl_chan)
+ return -EINVAL;
+
+ mutex_lock(>read_lock);
+ spin_lock_bh(>dl_pending_lock);
+ /* No data available to read, wait */
+ if (!uchan->cur_buf && list_empty(>dl_pending)) {
+ dev_dbg(dev, "No data available to read, waiting\n");
+
+ spin_unlock_bh(>dl_pending_lock);
+ ret = wait_event_interruptible(uchan->dl_wq,
+ (!udev->enabled ||
+
!list_empty(>dl_pending)));
If you need to protect dl_pending list against concurent access, you
need to do it in wait_event as well. I would suggest to lookg at
`wait_event_interruptible_lock_irq` function, that allows to pass a
locked spinlock as parameter. That would be safer and prevent this
lock/unlock dance.
When using this API difference is, first we take spin_lock_bh() and then
wait API is using spin_unlock_irq()/spin_lock_irq(). I am getting
"BUG: scheduling while atomic" when i use this way. When i changed
spin_lock_bh to spin_lock_irq then we got rid of the kernel BUG.
Thanks,
Hemant
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Re: [PATCH v9 3/4] docs: Add documentation for userspace client interface
Hi Jakub, On 10/26/20 3:56 PM, Jakub Kicinski wrote: On Mon, 26 Oct 2020 07:38:46 -0600 Jeffrey Hugo wrote: On 10/25/2020 3:46 PM, Jakub Kicinski wrote: On Fri, 23 Oct 2020 16:17:54 -0700 Hemant Kumar wrote: +UCI driver enables userspace clients to communicate to external MHI devices +like modem and WLAN. UCI driver probe creates standard character device file +nodes for userspace clients to perform open, read, write, poll and release file +operations. What's the user space that talks to this? Multiple. Each channel has a different purpose. There it is expected that a different userspace application would be using it. Hemant implemented the loopback channel, which is a simple channel that just sends you back anything you send it. Typically this is consumed by a test application. Diag is a typical channel to be consumed by userspace. This is consumed by various applications that talk to the remote device for diagnostic information (logs and such). Sahara is another common channel that is usually used for the multistage firmware loading process. Thanks for the info, are there any open source tests based on the loopback channel (perhaps even in tree?) Since that's the only channel enabled in this set its the only one we can comment on. i am not aware of any open source tests based on loopback channel. My testing includes multiple sessions of echo, cat etc using adb to confirm what is sent is received back. Loic is using UCI driver for his use case too. Loic, in case you have any use case (which is part of open source) which can use UCI driver, pls share that info ? I think as soon as UCI becomes part of the tree, more and more channels would get added to the driver having open source code for that from other folks in community (Loic would be one of them i guess). Thanks, Hemant -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v9 3/4] docs: Add documentation for userspace client interface
On 10/26/20 6:56 AM, Jeffrey Hugo wrote: On 10/26/2020 7:46 AM, Dan Williams wrote: On Mon, 2020-10-26 at 07:38 -0600, Jeffrey Hugo wrote: On 10/25/2020 3:46 PM, Jakub Kicinski wrote: On Fri, 23 Oct 2020 16:17:54 -0700 Hemant Kumar wrote: +UCI driver enables userspace clients to communicate to external MHI devices +like modem and WLAN. UCI driver probe creates standard character device file +nodes for userspace clients to perform open, read, write, poll and release file +operations. What's the user space that talks to this? Multiple. Each channel has a different purpose. There it is expected that a different userspace application would be using it. Hemant implemented the loopback channel, which is a simple channel that just sends you back anything you send it. Typically this is consumed by a test application. Diag is a typical channel to be consumed by userspace. This is consumed by various applications that talk to the remote device for diagnostic information (logs and such). QMI too? Dan Interesting question. My product doesn't use QMI. I would expect that all QMI runs through Router these days, but I am seeing some QMI channels in the downstream source. Hemant, Do you know what is the usecase for the QMI0/QMI1 channels? QMI0/QMI1 is used to send QMI message (control path) to bring the qmi rmnet data call. Thanks, Hemant -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v1 1/2] bus: mhi: core: Count number of HW channels supported by controller
Device provides the total number of HW channels it supports using MHI
configuration register. Host supported HW channels shall not exceed
that value. In order to make this check, a counter is needed to store
total number of HW channels required by host.
Signed-off-by: Hemant Kumar
---
drivers/bus/mhi/core/init.c | 2 ++
drivers/bus/mhi/core/internal.h | 1 +
include/linux/mhi.h | 1 +
3 files changed, 4 insertions(+)
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 0ffdebd..70fd6af 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -725,6 +725,8 @@ static int parse_ch_cfg(struct mhi_controller *mhi_cntrl,
mhi_chan = _cntrl->mhi_chan[chan];
mhi_chan->name = ch_cfg->name;
mhi_chan->chan = chan;
+ if (chan >= MHI_HW_CHAN_START_IDX)
+ mhi_cntrl->hw_chan++;
mhi_chan->tre_ring.elements = ch_cfg->num_elements;
if (!mhi_chan->tre_ring.elements)
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 7989269..3d8e480 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -454,6 +454,7 @@ enum mhi_pm_state {
#define PRIMARY_CMD_RING 0
#define MHI_DEV_WAKE_DB127
#define MHI_MAX_MTU0x
+#define MHI_HW_CHAN_START_IDX 100
#define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1)
enum mhi_er_type {
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index d4841e5..ea441d2 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -389,6 +389,7 @@ struct mhi_controller {
struct list_head lpm_chans;
int *irq;
u32 max_chan;
+ u32 hw_chan;
u32 total_ev_rings;
u32 hw_ev_rings;
u32 sw_ev_rings;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v1 2/2] bus: mhi: core: Check for device supported event rings and channels
It is possible that the device does not support the number of event
rings and channels that the controller would like to use. Read the
MHICFG to determine device-side support and if the controller requests
more than the device supports, bailout without configuring device MMIO
registers.
Signed-off-by: Hemant Kumar
---
drivers/bus/mhi/core/init.c | 31 +++
drivers/bus/mhi/core/internal.h | 4
2 files changed, 35 insertions(+)
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 70fd6af..35a6b1d 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -488,6 +488,37 @@ int mhi_init_mmio(struct mhi_controller *mhi_cntrl)
{ 0, 0, 0 }
};
+ /* range check b/w host and device supported ev rings and channels */
+ ret = mhi_read_reg(mhi_cntrl, base, MHICFG, );
+ if (ret) {
+ dev_err(dev, "Unable to read MHICFG register\n");
+ return -EIO;
+ }
+
+ if (MHICFG_NHWER(val) < mhi_cntrl->hw_ev_rings) {
+ dev_err(dev, "#HWEV ring: host requires %d dev supports %d\n",
+ mhi_cntrl->hw_ev_rings, MHICFG_NHWER(val));
+ return -EIO;
+ }
+
+ if (MHICFG_NER(val) < mhi_cntrl->total_ev_rings) {
+ dev_err(dev, "#EV ring: host requires %d dev supports %d\n",
+ mhi_cntrl->total_ev_rings, MHICFG_NER(val));
+ return -EIO;
+ }
+
+ if (MHICFG_NHWCH(val) < mhi_cntrl->hw_chan) {
+ dev_err(dev, "#HWCH: host requires %d dev supports %d\n",
+ mhi_cntrl->hw_chan, MHICFG_NHWCH(val));
+ return -EIO;
+ }
+
+ if (MHICFG_NCH(val) < mhi_cntrl->max_chan) {
+ dev_err(dev, "#CH: host requires %d dev supports %d\n",
+ mhi_cntrl->max_chan, MHICFG_NCH(val));
+ return -EIO;
+ }
+
dev_dbg(dev, "Initializing MHI registers\n");
/* Read channel db offset */
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 3d8e480..9cbfa71 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -28,6 +28,10 @@ extern struct bus_type mhi_bus_type;
#define MHICFG_NHWCH_SHIFT (8)
#define MHICFG_NCH_MASK (0xFF)
#define MHICFG_NCH_SHIFT (0)
+#define MHICFG_NHWER(n) (((n) & MHICFG_NHWER_MASK) >> MHICFG_NHWER_SHIFT)
+#define MHICFG_NER(n) (((n) & MHICFG_NER_MASK) >> MHICFG_NER_SHIFT)
+#define MHICFG_NHWCH(n) (((n) & MHICFG_NHWCH_MASK) >> MHICFG_NHWCH_SHIFT)
+#define MHICFG_NCH(n) (((n) & MHICFG_NCH_MASK) >> MHICFG_NCH_SHIFT)
#define CHDBOFF (0x18)
#define CHDBOFF_CHDBOFF_MASK (0x)
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v1 0/2] Check for device supported event rings and channels
This change is introduced to make sure device supported hardware event ring, hardware channels, total number of event rings and total number of channels match with MHI host controller. In case of a mismatch, driver bails out and does not move MHI device to M0 from Ready state. Hemant Kumar (2): bus: mhi: core: Count number of HW channels supported by controller bus: mhi: core: Check for device supported event rings and channels drivers/bus/mhi/core/init.c | 33 + drivers/bus/mhi/core/internal.h | 5 + include/linux/mhi.h | 1 + 3 files changed, 39 insertions(+) -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v9 1/4] bus: mhi: core: Add helper API to return number of free TREs
Introduce mhi_get_free_desc_count() API to return number
of TREs available to queue buffer. MHI clients can use this
API to know before hand if ring is full without calling queue
API.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/main.c | 12
include/linux/mhi.h | 9 +
2 files changed, 21 insertions(+)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 2cff5dd..3950792 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -258,6 +258,18 @@ int mhi_destroy_device(struct device *dev, void *data)
return 0;
}
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ struct mhi_chan *mhi_chan = (dir == DMA_TO_DEVICE) ?
+ mhi_dev->ul_chan : mhi_dev->dl_chan;
+ struct mhi_ring *tre_ring = _chan->tre_ring;
+
+ return get_nr_avail_ring_elements(mhi_cntrl, tre_ring);
+}
+EXPORT_SYMBOL_GPL(mhi_get_free_desc_count);
+
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
{
struct mhi_driver *mhi_drv;
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index d4841e5..7829b1d 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -597,6 +597,15 @@ void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl,
void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason);
/**
+ * mhi_get_free_desc_count - Get transfer ring length
+ * Get # of TD available to queue buffers
+ * @mhi_dev: Device associated with the channels
+ * @dir: Direction of the channel
+ */
+int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
+ enum dma_data_direction dir);
+
+/**
* mhi_prepare_for_power_up - Do pre-initialization before power up.
*This is optional, call this before power up if
*the controller does not want bus framework to
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v9 2/4] bus: mhi: core: Move MHI_MAX_MTU to external header file
Currently this macro is defined in internal MHI header as
a TRE length mask. Moving it to external header allows MHI
client drivers to set this upper bound for the transmit
buffer size.
Signed-off-by: Hemant Kumar
Reviewed-by: Jeffrey Hugo
Reviewed-by: Manivannan Sadhasivam
---
drivers/bus/mhi/core/internal.h | 1 -
include/linux/mhi.h | 3 +++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 7989269..4abf0cf 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -453,7 +453,6 @@ enum mhi_pm_state {
#define CMD_EL_PER_RING128
#define PRIMARY_CMD_RING 0
#define MHI_DEV_WAKE_DB127
-#define MHI_MAX_MTU0x
#define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1)
enum mhi_er_type {
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index 7829b1d..6e1122c 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -15,6 +15,9 @@
#include
#include
+/* MHI client drivers to set this upper bound for tx buffer */
+#define MHI_MAX_MTU 0x
+
#define MHI_MAX_OEM_PK_HASH_SEGMENTS 16
struct mhi_chan;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
[PATCH v9 4/4] bus: mhi: Add userspace client interface driver
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
/dev/mhi__
Currently it supports LOOPBACK channel.
Signed-off-by: Hemant Kumar
---
drivers/bus/mhi/Kconfig | 13 +
drivers/bus/mhi/Makefile | 4 +
drivers/bus/mhi/uci.c| 658 +++
3 files changed, 675 insertions(+)
create mode 100644 drivers/bus/mhi/uci.c
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index e841c10..476cc55 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -20,3 +20,16 @@ config MHI_BUS_DEBUG
Enable debugfs support for use with the MHI transport. Allows
reading and/or modifying some values within the MHI controller
for debug and test purposes.
+
+config MHI_UCI
+ tristate "MHI UCI"
+ depends on MHI_BUS
+ help
+ MHI based Userspace Client Interface (UCI) driver is used for
+ transferring raw data between host and device using standard file
+ operations from userspace. Open, read, write, and close operations
+ are supported by this driver. Please check mhi_uci_match_table for
+ all supported channels that are exposed to userspace.
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_uci.
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 19e6443..80feefb 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -1,2 +1,6 @@
# core layer
obj-y += core/
+
+# MHI client
+mhi_uci-y := uci.o
+obj-$(CONFIG_MHI_UCI) += mhi_uci.o
diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c
new file mode 100644
index 000..6c64356
--- /dev/null
+++ b/drivers/bus/mhi/uci.c
@@ -0,0 +1,658 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/
+
+#include
+#include
+#include
+#include
+#include
+
+#define DEVICE_NAME "mhi"
+#define MHI_UCI_DRIVER_NAME "mhi_uci"
+#define MAX_UCI_MINORS 128
+
+static DEFINE_IDR(uci_idr);
+static DEFINE_MUTEX(uci_drv_mutex);
+static struct class *uci_dev_class;
+static int uci_dev_major;
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_pending_lock: spin lock for dl_pending list
+ * @dl_pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending list in bh context, channel release, read and
+* poll
+*/
+ spinlock_t dl_pending_lock;
+
+ struct list_head dl_pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
+
+/**
+ * struct uci_buf - UCI buffer
+ * @data: data buffer
+ * @len: length of data buffer
+ * @node: list node of the UCI buffer
+ */
+struct uci_buf {
+ void *data;
+ size_t len;
+ struct list_head node;
+};
+
+/**
+ * struct uci_dev - MHI UCI device
+ * @minor: UCI device node minor number
+ * @mhi_dev: associated mhi device object
+ * @uchan: UCI uplink and downlink channel object
+ * @mtu: max TRE buffer length
+ * @enabled: Flag to track the state of the UCI device
+ * @lock: mutex lock to manage uchan object
+ * @ref_count: uci_dev reference count
+ */
+struct uci_dev {
+ unsigned int minor;
+ struct mhi_device *mhi_dev;
+ struct uci_chan *uchan;
+ size_t mtu;
+ bool enabled;
+
+ /* synchronize open, release and driver remove */
+ struct mutex lock;
+ struct kref ref_count;
+};
+
+static void mhi_uci_dev_chan_release(struct kref *ref)
+{
+ struct uci_buf *buf_itr, *tmp;
+ struct uci_chan *uchan =
+ container_of(ref, struct uci_chan, ref_count);
+
+ if (uchan->udev->enabled)
+ mhi_unprepare_from_transfer(uchan->
[PATCH v9 3/4] docs: Add documentation for userspace client interface
MHI userspace client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently Loopback MHI channel is supported by this driver. Signed-off-by: Hemant Kumar --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 83 + 2 files changed, 84 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 000..fe901c4 --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,83 @@ +.. SPDX-License-Identifier: GPL-2.0 + += +Userspace Client Interface (UCI) += + +UCI driver enables userspace clients to communicate to external MHI devices +like modem and WLAN. UCI driver probe creates standard character device file +nodes for userspace clients to perform open, read, write, poll and release file +operations. + +Operations +== + +open + + +Instantiates UCI channel object and starts MHI channels to move it to running +state. Inbound buffers are queued to downlink channel transfer ring. Every +subsequent open() increments UCI device reference count as well as UCI channel +reference count. + +read + + +When data transfer is completed on downlink channel, TRE buffer is copied to +pending list. Reader is unblocked and data is copied to userspace buffer. TRE +buffer is queued back to downlink channel transfer ring. + +write +- + +Write buffer is queued to uplink channel transfer ring if ring is not full. Upon +uplink transfer completion buffer is freed. + +poll + + +Returns EPOLLIN | EPOLLRDNORM mask if pending list has buffers to be read by +userspace. Returns EPOLLOUT | EPOLLWRNORM mask if MHI uplink channel transfer +ring is not empty. Returns EPOLLERR when UCI driver is removed. MHI channels +move to disabled state upon driver remove. + +release +--- + +Decrements UCI device reference count and UCI channel reference count upon last +release(). UCI channel clean up is performed. MHI channel moves to disabled +state and inbound buffers are freed. + +Usage += + +Device file node is created with format:- + +/dev/mhi__ + +controller_name is the name of underlying bus used to transfer data. mhi_device +name is the name of the MHI channel being used by MHI client in userspace to +send or receive data using MHI protocol. + +There is a separate character device file node created for each channel +specified in mhi device id table. MHI channels are statically defined by MHI +specification. The list of supported channels is in the channel list variable +of mhi_device_id table in UCI driver. + +LOOPBACK Channel + + +Userspace MHI client using LOOPBACK channel opens device file node. As part of +open operation TREs to transfer ring of LOOPBACK channel 1 gets queued and channel +doorbell is rung. When userspace MHI client performs write operation on device node, +data buffer gets queued as a TRE to transfer ring of LOOPBACK channel 0. MHI Core +driver rings the channel doorbell for MHI device to move data over underlying bus. +When userspace MHI client driver performs read operation, same data gets looped back +to MHI host using LOOPBACK channel 1. LOOPBACK channel is used to verify data path +and data integrity between MHI Host and MHI device. + +Other Use Cases +--- + +Getting MHI device specific diagnostics information to userspace MHI diag client +using DIAG channel 4 (Host to device) and 5 (Device to Host). -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
[PATCH v9 0/4] userspace MHI client interface driver
This patch series adds support for UCI driver. UCI driver enables userspace clients to communicate to external MHI devices like modem and WLAN. UCI driver probe creates standard character device file nodes for userspace clients to perform open, read, write, poll and release file operations. These file operations call MHI core layer APIs to perform data transfer using MHI bus to communicate with MHI device. Patch is tested using arm64 based platform. V9: - Renamed dl_lock to dl_pending _lock and pending list to dl_pending for clarity. - Used read lock to protect cur_buf. - Change transfer status check logic and only consider 0 and -EOVERFLOW as only success. - Added __int to module init function. - Print channel name instead of minor number upon successful probe. V8: - Fixed kernel test robot compilation error by changing %lu to %zu for size_t. - Replaced uci with UCI in Kconfig, commit text, and comments in driver code. - Fixed minor style related comments. V7: - Decoupled uci device and uci channel objects. uci device is associated with device file node. uci channel is associated with MHI channels. uci device refers to uci channel to perform MHI channel operations for device file operations like read() and write(). uci device increments its reference count for every open(). uci device calls mhi_uci_dev_start_chan() to start the MHI channel. uci channel object is tracking number of times MHI channel is referred. This allows to keep the MHI channel in start state until last release() is called. After that uci channel reference count goes to 0 and uci channel clean up is performed which stops the MHI channel. After the last call to release() if driver is removed uci reference count becomes 0 and uci object is cleaned up. - Use separate uci channel read and write lock to fine grain locking between reader and writer. - Use uci device lock to synchronize open, release and driver remove. - Optimize for downlink only or uplink only UCI device. V6: - Moved uci.c to mhi directory. - Updated Kconfig to add module information. - Updated Makefile to rename uci object file name as mhi_uci - Removed kref for open count V5: - Removed mhi_uci_drv structure. - Used idr instead of creating global list of uci devices. - Used kref instead of local ref counting for uci device and open count. - Removed unlikely macro. V4: - Fix locking to protect proper struct members. - Updated documentation describing uci client driver use cases. - Fixed uci ref counting in mhi_uci_open for error case. - Addressed style related review comments. V3: Added documentation for MHI UCI driver. V2: Added mutex lock to prevent multiple readers to access same mhi buffer which can result into use after free. Hemant Kumar (4): bus: mhi: core: Add helper API to return number of free TREs bus: mhi: core: Move MHI_MAX_MTU to external header file docs: Add documentation for userspace client interface bus: mhi: Add userspace client interface driver Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 83 + drivers/bus/mhi/Kconfig | 13 + drivers/bus/mhi/Makefile| 4 + drivers/bus/mhi/core/internal.h | 1 - drivers/bus/mhi/core/main.c | 12 + drivers/bus/mhi/uci.c | 658 include/linux/mhi.h | 12 + 8 files changed, 783 insertions(+), 1 deletion(-) create mode 100644 Documentation/mhi/uci.rst create mode 100644 drivers/bus/mhi/uci.c -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v8 0/4] userspace MHI client interface driver
Hi Jakub, On 10/23/20 9:37 AM, Jakub Kicinski wrote: On Thu, 22 Oct 2020 01:22:34 -0700 Hemant Kumar wrote: This patch series adds support for UCI driver. UCI driver enables userspace clients to communicate to external MHI devices like modem and WLAN. UCI driver probe creates standard character device file nodes for userspace clients to perform open, read, write, poll and release file operations. These file operations call MHI core layer APIs to perform data transfer using MHI bus to communicate with MHI device. Patch is tested using arm64 based platform. Until you CC netdev on this (as suggested [1]), here's my: Nacked-by: Jakub Kicinski [1] https://lore.kernel.org/netdev/20201016183759.7fa7c...@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com/ UCI driver patch series includes following patches 1) bus: mhi: core: Add helper API to return number of free TREs 2) bus: mhi: core: Move MHI_MAX_MTU to external header file 3) docs: Add documentation for userspace client interface 4) bus: mhi: Add userspace client interface driver mhi net driver can use #1 and #2 and these two are part of MHI core driver change. These are helper API/macro which can be used by any mhi clients like UCI or mhi net dev. #3 and #4 are MHI UCI character driver completely unrelated to netdev. How about splitting the patch series between #1,#2 and #3, #4 and add netdev to #1, #2? #1,#2 were already reviewed by two folks in community so it would be much easier for netdev folks to refer that in context of mhi net device driver. Please let me know what do you think about this idea. Thanks, Hemant -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v8 4/4] bus: mhi: Add userspace client interface driver
Hi Loic,
On 10/22/20 3:20 AM, Loic Poulain wrote:
Hi Hemant,
A few comments inline.
On Thu, 22 Oct 2020 at 10:22, Hemant Kumar wrote:
This MHI client driver allows userspace clients to transfer
raw data between MHI device and host using standard file operations.
Driver instantiates UCI device object which is associated to device
file node. UCI device object instantiates UCI channel object when device
file node is opened. UCI channel object is used to manage MHI channels
by calling MHI core APIs for read and write operations. MHI channels
are started as part of device open(). MHI channels remain in start
state until last release() is called on UCI device file node. Device
file node is created with format
[..]
+
+/**
+ * struct uci_chan - MHI channel for a UCI device
+ * @udev: associated UCI device object
+ * @ul_wq: wait queue for writer
+ * @write_lock: mutex write lock for ul channel
+ * @dl_wq: wait queue for reader
+ * @read_lock: mutex read lock for dl channel
+ * @dl_lock: spin lock
+ * @pending: list of dl buffers userspace is waiting to read
+ * @cur_buf: current buffer userspace is reading
+ * @dl_size: size of the current dl buffer userspace is reading
+ * @ref_count: uci_chan reference count
+ */
+struct uci_chan {
+ struct uci_dev *udev;
+ wait_queue_head_t ul_wq;
+
+ /* ul channel lock to synchronize multiple writes */
+ struct mutex write_lock;
+
+ wait_queue_head_t dl_wq;
+
+ /* dl channel lock to synchronize multiple reads */
+ struct mutex read_lock;
+
+ /*
+* protects pending and cur_buf members in bh context, channel release,
+* read and poll
+*/
+ spinlock_t dl_lock;
Maybe I'm wrong, but I think it would be clearer and simpler for
dl_lock to be only a lock for the pending RX list (e.g. pending_lock),
for protecting against concurrent access in chardev read ops
(consumer) and MHI download callback (producer). cur_buf is the
currently read buffer, and so could be simply protected by the
read_lock mutex (never accessed from bh/irq callback context).
You have a good point. I can protect pending list related operations
using spin lock and call it pending_lock which would be used in dl_xfer
call back, channel release, read and poll. Use read lock for cur_buf in
read().
+
+ struct list_head pending;
+ struct uci_buf *cur_buf;
+ size_t dl_size;
+ struct kref ref_count;
+};
+
+/**
[..]
+static void mhi_dl_xfer_cb(struct mhi_device *mhi_dev,
+ struct mhi_result *mhi_result)
+{
+ struct uci_dev *udev = dev_get_drvdata(_dev->dev);
+ struct uci_chan *uchan = udev->uchan;
+ struct device *dev = _dev->dev;
+ struct uci_buf *ubuf;
+ size_t dl_buf_size = udev->mtu - sizeof(*ubuf);
+
+ dev_dbg(dev, "status: %d receive_len: %zu\n",
+ mhi_result->transaction_status, mhi_result->bytes_xferd);
+
+ if (mhi_result->transaction_status == -ENOTCONN) {
+ kfree(mhi_result->buf_addr);
+ return;
+ }
It would be more robust to test only transaction_status values that
allow you to consider the buffer as valid, AFAIU 0 and -EOVERFLOW.
That would prevent breaking that code if new transaction_status errors
are returned in the futur (e.g. -EIO...).
I agree, will use this instead
if (mhi_result->transaction_status &&
mhi_result->transaction_status != -EOVERFLOW)
+
+ ubuf = mhi_result->buf_addr + dl_buf_size;
+ ubuf->data = mhi_result->buf_addr;
+ ubuf->len = mhi_result->bytes_xferd;
+ spin_lock_bh(>dl_lock);
+ list_add_tail(>node, >pending);
+ spin_unlock_bh(>dl_lock);
+
+ wake_up(>dl_wq);
+}
+
Thanks,
Hemant
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