Currently on platforms designed for Windows, connections between CIO2 and
sensors are not properly defined in DSDT. This patch extends the ipu3-cio2
driver to compensate by building software_node connections, parsing the
connection properties from the sensor's SSDB buffer.

Suggested-by: Jordan Hand <[email protected]>
Signed-off-by: Daniel Scally <[email protected]>
---
Changes since RFC v3:

        - Removed almost all global variables, dynamically allocated
        the cio2_bridge structure, plus a bunch of associated changes
        like 
        - Added a new function to ipu3-cio2-main.c to check for an 
        existing fwnode_graph before calling cio2_bridge_init()
        - Prefixed cio2_bridge_ to any variables and functions that
        lacked it
        - Assigned the new fwnode directly to the sensor's ACPI device
        fwnode as secondary. This removes the requirement to delay until
        the I2C devices are instantiated before ipu3-cio2 can probe, but
        it has a side effect, which is that those devices then grab a ref
        to the new software_node. This effectively prevents us from
        unloading the driver, because we can't free the memory that they
        live in whilst the device holds a reference to them. The work
        around at the moment is to _not_ unregister the software_nodes
        when ipu3-cio2 is unloaded; this becomes a one-time 'patch', that
        is simply skipped if the module is reloaded.
        - Moved the sensor's SSDB struct to be a member of cio2_sensor
        - Replaced ints with unsigned ints where appropriate
        - Iterated over all ACPI devices of a matching _HID rather than
        just the first to ensure we handle a device with multiple sensors
        of the same model.

 MAINTAINERS                                   |   1 +
 drivers/media/pci/intel/ipu3/Kconfig          |  18 ++
 drivers/media/pci/intel/ipu3/Makefile         |   1 +
 drivers/media/pci/intel/ipu3/cio2-bridge.c    | 260 ++++++++++++++++++
 drivers/media/pci/intel/ipu3/cio2-bridge.h    | 108 ++++++++
 drivers/media/pci/intel/ipu3/ipu3-cio2-main.c |  27 ++
 drivers/media/pci/intel/ipu3/ipu3-cio2.h      |   6 +
 7 files changed, 421 insertions(+)
 create mode 100644 drivers/media/pci/intel/ipu3/cio2-bridge.c
 create mode 100644 drivers/media/pci/intel/ipu3/cio2-bridge.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 9702b886d6a4..188559a0a610 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8927,6 +8927,7 @@ INTEL IPU3 CSI-2 CIO2 DRIVER
 M:     Yong Zhi <[email protected]>
 M:     Sakari Ailus <[email protected]>
 M:     Bingbu Cao <[email protected]>
+M:     Dan Scally <[email protected]>
 R:     Tianshu Qiu <[email protected]>
 L:     [email protected]
 S:     Maintained
diff --git a/drivers/media/pci/intel/ipu3/Kconfig 
b/drivers/media/pci/intel/ipu3/Kconfig
index 82d7f17e6a02..2b3350d042be 100644
--- a/drivers/media/pci/intel/ipu3/Kconfig
+++ b/drivers/media/pci/intel/ipu3/Kconfig
@@ -16,3 +16,21 @@ config VIDEO_IPU3_CIO2
          Say Y or M here if you have a Skylake/Kaby Lake SoC with MIPI CSI-2
          connected camera.
          The module will be called ipu3-cio2.
+
+config CIO2_BRIDGE
+       bool "IPU3 CIO2 Sensors Bridge"
+       depends on VIDEO_IPU3_CIO2
+       help
+         This extension provides an API for the ipu3-cio2 driver to create
+         connections to cameras that are hidden in SSDB buffer in ACPI. It
+         can be used to enable support for cameras in detachable / hybrid
+         devices that ship with Windows.
+
+         Say Y here if your device is a detachable / hybrid laptop that comes
+         with Windows installed by the OEM, for example:
+
+               - Microsoft Surface models (except Surface Pro 3)
+               - The Lenovo Miix line (for example the 510, 520, 710 and 720)
+               - Dell 7285
+
+         If in doubt, say N here.
diff --git a/drivers/media/pci/intel/ipu3/Makefile 
b/drivers/media/pci/intel/ipu3/Makefile
index 429d516452e4..933777e6ea8a 100644
--- a/drivers/media/pci/intel/ipu3/Makefile
+++ b/drivers/media/pci/intel/ipu3/Makefile
@@ -2,3 +2,4 @@
 obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2.o
 
 ipu3-cio2-y += ipu3-cio2-main.o
+ipu3-cio2-$(CONFIG_CIO2_BRIDGE) += cio2-bridge.o
diff --git a/drivers/media/pci/intel/ipu3/cio2-bridge.c 
b/drivers/media/pci/intel/ipu3/cio2-bridge.c
new file mode 100644
index 000000000000..fd3f8ba07274
--- /dev/null
+++ b/drivers/media/pci/intel/ipu3/cio2-bridge.c
@@ -0,0 +1,260 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dan Scally <[email protected]> */
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/property.h>
+#include <media/v4l2-subdev.h>
+
+#include "cio2-bridge.h"
+
+/*
+ * Extend this array with ACPI Hardware ID's of devices known to be working.
+ * Do not add a HID for a sensor that is not actually supported.
+ */
+static const char * const cio2_supported_devices[] = {
+       "INT33BE",
+       "OVTI2680",
+};
+
+static int cio2_bridge_read_acpi_buffer(struct acpi_device *adev, char *id,
+                                       void *data, u32 size)
+{
+       struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+       union acpi_object *obj;
+       acpi_status status;
+       int ret;
+
+       status = acpi_evaluate_object(adev->handle, id, NULL, &buffer);
+       if (ACPI_FAILURE(status))
+               return -ENODEV;
+
+       obj = buffer.pointer;
+       if (!obj) {
+               dev_err(&adev->dev, "Couldn't locate ACPI buffer\n");
+               return -ENODEV;
+       }
+
+       if (obj->type != ACPI_TYPE_BUFFER) {
+               dev_err(&adev->dev, "Not an ACPI buffer\n");
+               ret = -ENODEV;
+               goto out_free_buff;
+       }
+
+       if (obj->buffer.length > size) {
+               dev_err(&adev->dev, "Given buffer is too small\n");
+               ret = -EINVAL;
+               goto out_free_buff;
+       }
+
+       memcpy(data, obj->buffer.pointer, obj->buffer.length);
+       ret = obj->buffer.length;
+
+out_free_buff:
+       kfree(buffer.pointer);
+       return ret;
+}
+
+static void cio2_bridge_init_property_names(struct cio2_sensor *sensor)
+{
+       strcpy(sensor->prop_names.clock_frequency, "clock-frequency");
+       strcpy(sensor->prop_names.rotation, "rotation");
+       strcpy(sensor->prop_names.bus_type, "bus-type");
+       strcpy(sensor->prop_names.data_lanes, "data-lanes");
+       strcpy(sensor->prop_names.remote_endpoint, "remote-endpoint");
+}
+
+static void cio2_bridge_create_fwnode_properties(struct cio2_sensor *sensor)
+{
+       unsigned int i;
+
+       cio2_bridge_init_property_names(sensor);
+
+       for (i = 0; i < 4; i++)
+               sensor->data_lanes[i] = i + 1;
+
+       /*
+        * Can't use PROPERTY_ENTRY_REF because it creates a new variable to
+        * point to, which doesn't survive the function.
+        */
+       sensor->local_ref[0] = (struct software_node_ref_args){
+               .node = &sensor->swnodes[SWNODE_CIO2_ENDPOINT]
+               };
+       sensor->remote_ref[0] = (struct software_node_ref_args){
+               .node = &sensor->swnodes[SWNODE_SENSOR_ENDPOINT]
+               };
+
+       sensor->dev_properties[0] = 
PROPERTY_ENTRY_U32(sensor->prop_names.clock_frequency,
+                                                      sensor->ssdb.mclkspeed);
+       sensor->dev_properties[1] = 
PROPERTY_ENTRY_U8(sensor->prop_names.rotation,
+                                                     sensor->ssdb.degree);
+
+       sensor->ep_properties[0] = 
PROPERTY_ENTRY_U32(sensor->prop_names.bus_type, 5);
+       sensor->ep_properties[1] = 
PROPERTY_ENTRY_U32_ARRAY_LEN(sensor->prop_names.data_lanes,
+                                                               
sensor->data_lanes,
+                                                               
sensor->ssdb.lanes);
+       sensor->ep_properties[2] = 
PROPERTY_ENTRY_REF_ARRAY(sensor->prop_names.remote_endpoint,
+                                                           sensor->local_ref);
+
+       sensor->cio2_properties[0] = 
PROPERTY_ENTRY_U32_ARRAY_LEN(sensor->prop_names.data_lanes,
+                                                                 
sensor->data_lanes,
+                                                                 
sensor->ssdb.lanes);
+       sensor->cio2_properties[1] = 
PROPERTY_ENTRY_REF_ARRAY(sensor->prop_names.remote_endpoint,
+                                                             
sensor->remote_ref);
+}
+
+static void cio2_bridge_init_swnode_names(struct cio2_sensor *sensor)
+{
+       snprintf(sensor->node_names.remote_port, 6, "port%u", 
sensor->ssdb.link);
+       strcpy(sensor->node_names.port, "port0");
+       strcpy(sensor->node_names.endpoint, "endpoint0");
+}
+
+static void cio2_bridge_create_connection_swnodes(struct cio2_bridge *bridge,
+                                                 struct cio2_sensor *sensor)
+{
+       struct software_node *nodes = sensor->swnodes;
+
+       cio2_bridge_init_swnode_names(sensor);
+
+       nodes[SWNODE_SENSOR_HID] = NODE_SENSOR(sensor->name,
+                                              sensor->dev_properties);
+       nodes[SWNODE_SENSOR_PORT] = NODE_PORT(sensor->node_names.port,
+                                             &nodes[SWNODE_SENSOR_HID]);
+       nodes[SWNODE_SENSOR_ENDPOINT] = 
NODE_ENDPOINT(sensor->node_names.endpoint,
+                                                     
&nodes[SWNODE_SENSOR_PORT],
+                                                     sensor->ep_properties);
+       nodes[SWNODE_CIO2_PORT] = NODE_PORT(sensor->node_names.remote_port,
+                                           &bridge->cio2_hid_node);
+       nodes[SWNODE_CIO2_ENDPOINT] = NODE_ENDPOINT(sensor->node_names.endpoint,
+                                                   &nodes[SWNODE_CIO2_PORT],
+                                                   sensor->cio2_properties);
+}
+
+static void cio2_bridge_unregister_sensors(struct cio2_bridge *bridge)
+{
+       struct cio2_sensor *sensor;
+       unsigned int i;
+
+       for (i = 0; i < bridge->n_sensors; i++) {
+               sensor = &bridge->sensors[i];
+               software_node_unregister_nodes(sensor->swnodes);
+               acpi_dev_put(sensor->adev);
+       }
+}
+
+static int cio2_bridge_connect_sensors(struct cio2_bridge *bridge)
+{
+       struct fwnode_handle *fwnode;
+       struct cio2_sensor *sensor;
+       struct acpi_device *adev;
+       unsigned int i;
+       int ret = 0;
+
+       for (i = 0; i < ARRAY_SIZE(cio2_supported_devices); i++) {
+               const char *this_device = cio2_supported_devices[i];
+
+               for_each_acpi_dev_match(adev, this_device, NULL, -1) {
+                       if (!adev || !(adev->status.present && 
adev->status.enabled))
+                               continue;
+
+                       sensor = &bridge->sensors[bridge->n_sensors];
+                       sensor->adev = adev;
+                       strscpy(sensor->name, this_device, 
sizeof(sensor->name));
+
+                       ret = cio2_bridge_read_acpi_buffer(adev, "SSDB",
+                                                          &sensor->ssdb,
+                                                          
sizeof(sensor->ssdb));
+                       if (ret < 0)
+                               goto err_put_adev;
+
+                       if (sensor->ssdb.lanes > 4) {
+                               dev_err(&adev->dev,
+                                       "Number of lanes in SSDB is invalid\n");
+                               goto err_put_adev;
+                       }
+
+                       cio2_bridge_create_fwnode_properties(sensor);
+                       cio2_bridge_create_connection_swnodes(bridge, sensor);
+
+                       ret = software_node_register_nodes(sensor->swnodes);
+                       if (ret)
+                               goto err_put_adev;
+
+                       fwnode = 
software_node_fwnode(&sensor->swnodes[SWNODE_SENSOR_HID]);
+                       if (!fwnode) {
+                               ret = -ENODEV;
+                               goto err_free_swnodes;
+                       }
+
+                       adev->fwnode.secondary = fwnode;
+
+                       dev_info(&bridge->cio2->dev,
+                                "Found supported sensor %s\n",
+                                acpi_dev_name(adev));
+
+                       bridge->n_sensors++;
+               }
+       }
+
+       return ret;
+
+err_free_swnodes:
+       software_node_unregister_nodes(sensor->swnodes);
+err_put_adev:
+       acpi_dev_put(sensor->adev);
+
+       return ret;
+}
+
+int cio2_bridge_init(struct pci_dev *cio2)
+{
+       struct device *dev = &cio2->dev;
+       struct fwnode_handle *fwnode;
+       struct cio2_bridge *bridge;
+       int ret;
+
+       bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
+       if (!bridge)
+               return -ENOMEM;
+
+       strscpy(bridge->cio2_node_name, CIO2_HID, 
sizeof(bridge->cio2_node_name));
+       bridge->cio2_hid_node = (const struct software_node){ 
bridge->cio2_node_name };
+       bridge->cio2 = pci_dev_get(cio2);
+
+       ret = software_node_register(&bridge->cio2_hid_node);
+       if (ret < 0) {
+               dev_err(dev, "Failed to register the CIO2 HID node\n");
+               goto err_put_cio2;
+       }
+
+       ret = cio2_bridge_connect_sensors(bridge);
+       if (ret || bridge->n_sensors == 0)
+               goto err_unregister_cio2;
+
+       dev_info(dev, "Connected %d cameras\n", bridge->n_sensors);
+
+       fwnode = software_node_fwnode(&bridge->cio2_hid_node);
+       if (!fwnode) {
+               dev_err(dev, "Error getting fwnode from cio2 software_node\n");
+               ret = -ENODEV;
+               goto err_unregister_sensors;
+       }
+
+       set_secondary_fwnode(dev, fwnode);
+
+       return 0;
+
+err_unregister_sensors:
+       cio2_bridge_unregister_sensors(bridge);
+err_unregister_cio2:
+       software_node_unregister(&bridge->cio2_hid_node);
+err_put_cio2:
+       pci_dev_put(bridge->cio2);
+
+       kfree(bridge);
+       return ret;
+}
diff --git a/drivers/media/pci/intel/ipu3/cio2-bridge.h 
b/drivers/media/pci/intel/ipu3/cio2-bridge.h
new file mode 100644
index 000000000000..96f5c8a12be0
--- /dev/null
+++ b/drivers/media/pci/intel/ipu3/cio2-bridge.h
@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Author: Dan Scally <[email protected]> */
+#ifndef __CIO2_BRIDGE_H
+#define __CIO2_BRIDGE_H
+
+#include <linux/property.h>
+
+#define CIO2_HID                               "INT343E"
+#define CIO2_NUM_PORTS                   4
+
+#define NODE_SENSOR(_HID, _PROPS)              \
+       ((const struct software_node) {         \
+               .name = _HID,                   \
+               .properties = _PROPS,           \
+       })
+
+#define NODE_PORT(_PORT, _SENSOR_NODE)         \
+       ((const struct software_node) {         \
+               _PORT,                          \
+               _SENSOR_NODE,                   \
+       })
+
+#define NODE_ENDPOINT(_EP, _PORT, _PROPS)      \
+       ((const struct software_node) {         \
+               _EP,                            \
+               _PORT,                          \
+               _PROPS,                         \
+       })
+
+enum cio2_sensor_swnodes {
+       SWNODE_SENSOR_HID,
+       SWNODE_SENSOR_PORT,
+       SWNODE_SENSOR_ENDPOINT,
+       SWNODE_CIO2_PORT,
+       SWNODE_CIO2_ENDPOINT,
+       NR_OF_SENSOR_SWNODES
+};
+
+/* Data representation as it is in ACPI SSDB buffer */
+struct cio2_sensor_ssdb {
+       u8 version;
+       u8 sku;
+       u8 guid_csi2[16];
+       u8 devfunction;
+       u8 bus;
+       u32 dphylinkenfuses;
+       u32 clockdiv;
+       u8 link;
+       u8 lanes;
+       u32 csiparams[10];
+       u32 maxlanespeed;
+       u8 sensorcalibfileidx;
+       u8 sensorcalibfileidxInMBZ[3];
+       u8 romtype;
+       u8 vcmtype;
+       u8 platforminfo;
+       u8 platformsubinfo;
+       u8 flash;
+       u8 privacyled;
+       u8 degree;
+       u8 mipilinkdefined;
+       u32 mclkspeed;
+       u8 controllogicid;
+       u8 reserved1[3];
+       u8 mclkport;
+       u8 reserved2[13];
+} __packed__;
+
+struct cio2_property_names {
+       char clock_frequency[16];
+       char rotation[9];
+       char bus_type[9];
+       char data_lanes[11];
+       char remote_endpoint[16];
+};
+
+struct cio2_node_names {
+       char port[6];
+       char endpoint[10];
+       char remote_port[6];
+};
+
+struct cio2_sensor {
+       char name[ACPI_ID_LEN];
+       struct acpi_device *adev;
+
+       struct software_node swnodes[6];
+       struct cio2_node_names node_names;
+
+       u32 data_lanes[4];
+       struct cio2_sensor_ssdb ssdb;
+       struct cio2_property_names prop_names;
+       struct property_entry ep_properties[4];
+       struct property_entry dev_properties[3];
+       struct property_entry cio2_properties[3];
+       struct software_node_ref_args local_ref[1];
+       struct software_node_ref_args remote_ref[1];
+};
+
+struct cio2_bridge {
+       struct pci_dev *cio2;
+       char cio2_node_name[ACPI_ID_LEN];
+       struct software_node cio2_hid_node;
+       unsigned int n_sensors;
+       struct cio2_sensor sensors[CIO2_NUM_PORTS];
+};
+
+#endif
diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c 
b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
index 36e354ecf71e..0d69b593e9f0 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
@@ -1702,6 +1702,22 @@ static void cio2_queues_exit(struct cio2_device *cio2)
                cio2_queue_exit(cio2, &cio2->queue[i]);
 }
 
+static bool cio2_check_fwnode_graph(struct fwnode_handle *fwnode)
+{
+       struct fwnode_handle *endpoint;
+
+       if (IS_ERR_OR_NULL(fwnode))
+               return false;
+
+       endpoint = fwnode_graph_get_next_endpoint(fwnode, NULL);
+       if (endpoint) {
+               fwnode_handle_put(endpoint);
+               return true;
+       }
+
+       return cio2_check_fwnode_graph(fwnode->secondary);
+}
+
 /**************** PCI interface ****************/
 
 static int cio2_pci_probe(struct pci_dev *pci_dev,
@@ -1715,6 +1731,17 @@ static int cio2_pci_probe(struct pci_dev *pci_dev,
                return -ENOMEM;
        cio2->pci_dev = pci_dev;
 
+       /*
+        * On some platforms no connections to sensors are defined in firmware,
+        * if the device has no endpoints then we can try to build those as
+        * software_nodes parsed from SSDB.
+        */
+       if (!cio2_check_fwnode_graph(dev_fwnode(&pci_dev->dev))) {
+               r = cio2_bridge_init(pci_dev);
+               if (r)
+                       return r;
+       }
+
        r = pcim_enable_device(pci_dev);
        if (r) {
                dev_err(&pci_dev->dev, "failed to enable device (%d)\n", r);
diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2.h 
b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
index ccf0b85ae36f..520a27c9cdad 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2.h
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
@@ -437,4 +437,10 @@ static inline struct cio2_queue *vb2q_to_cio2_queue(struct 
vb2_queue *vq)
        return container_of(vq, struct cio2_queue, vbq);
 }
 
+#if IS_ENABLED(CONFIG_CIO2_BRIDGE)
+int cio2_bridge_init(struct pci_dev *cio2);
+#else
+int cio2_bridge_init(struct pci_dev *cio2) { return 0; }
+#endif
+
 #endif
-- 
2.25.1

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