This driver is a logical device which provides an
interface between the hypervisor and a management
partition. This interface is like a message
passing interface. This management partition
is intended to provide an alternative to HMC-based
system management.

VMC enables the Management LPAR to provide basic
logical partition functions:
- Logical Partition Configuration
- Boot, start, and stop actions for individual
  partitions
- Display of partition status
- Management of virtual Ethernet
- Management of virtual Storage
- Basic system management

This driver is to be used for the POWER Virtual
Management Channel Virtual Adapter on the PowerPC
platform. It provides a character device which
allows for both request/response and async message
support through the /dev/ibmvmc node.

Signed-off-by: Bryant G. Ly <bryan...@linux.vnet.ibm.com>
Reviewed-by: Steven Royer <sero...@linux.vnet.ibm.com>
Reviewed-by: Adam Reznechek <adrez...@linux.vnet.ibm.com>
Reviewed-by: Randy Dunlap <rdun...@infradead.org>
Tested-by: Taylor Jakobson <tjak...@us.ibm.com>
Tested-by: Brad Warrum <bwar...@us.ibm.com>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Cc: Arnd Bergmann <a...@arndb.de>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Michael Ellerman <m...@ellerman.id.au>
---
 Documentation/ioctl/ioctl-number.txt  |    1 +
 Documentation/misc-devices/ibmvmc.rst |  226 +++
 MAINTAINERS                           |    6 +
 arch/powerpc/include/asm/hvcall.h     |    1 +
 drivers/misc/Kconfig                  |   14 +
 drivers/misc/Makefile                 |    1 +
 drivers/misc/ibmvmc.c                 | 2418 +++++++++++++++++++++++++++++++++
 drivers/misc/ibmvmc.h                 |  209 +++
 8 files changed, 2876 insertions(+)
 create mode 100644 Documentation/misc-devices/ibmvmc.rst
 create mode 100644 drivers/misc/ibmvmc.c
 create mode 100644 drivers/misc/ibmvmc.h

diff --git a/Documentation/ioctl/ioctl-number.txt 
b/Documentation/ioctl/ioctl-number.txt
index 84bb74d..9851cee 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -329,6 +329,7 @@ Code  Seq#(hex)     Include File            Comments
 0xCA   80-BF   uapi/scsi/cxlflash_ioctl.h
 0xCB   00-1F   CBM serial IEC bus      in development:
                                        
<mailto:michael.kl...@puffin.lb.shuttle.de>
+0xCC   00-0F   drivers/misc/ibmvmc.h    pseries VMC driver
 0xCD   01      linux/reiserfs_fs.h
 0xCF   02      fs/cifs/ioctl.c
 0xDB   00-0F   drivers/char/mwave/mwavepub.h
diff --git a/Documentation/misc-devices/ibmvmc.rst 
b/Documentation/misc-devices/ibmvmc.rst
new file mode 100644
index 0000000..46ded79
--- /dev/null
+++ b/Documentation/misc-devices/ibmvmc.rst
@@ -0,0 +1,226 @@
+.. SPDX-License-Identifier: GPL-2.0+
+======================================================
+IBM Virtual Management Channel Kernel Driver (IBMVMC)
+======================================================
+
+:Authors:
+       Dave Engebretsen <engeb...@us.ibm.com>,
+       Adam Reznechek <adrez...@linux.vnet.ibm.com>,
+       Steven Royer <sero...@linux.vnet.ibm.com>,
+       Bryant G. Ly <bryan...@linux.vnet.ibm.com>,
+
+Introduction
+============
+
+Note: Knowledge of virtualization technology is required to understand
+this document.
+
+A good reference document would be:
+
+https://openpowerfoundation.org/wp-content/uploads/2016/05/LoPAPR_DRAFT_v11_24March2016_cmt1.pdf
+
+The Virtual Management Channel (VMC) is a logical device which provides an
+interface between the hypervisor and a management partition. This interface
+is like a message passing interface. This management partition is intended
+to provide an alternative to systems that use a Hardware Management
+Console (HMC) - based system management.
+
+The primary hardware management solution that is developed by IBM relies
+on an appliance server named the Hardware Management Console (HMC),
+packaged as an external tower or rack-mounted personal computer. In a
+Power Systems environment, a single HMC can manage multiple POWER
+processor-based systems.
+
+Management Application
+----------------------
+
+In the management partition, a management application exists which enables
+a system administrator to configure the system’s partitioning
+characteristics via a command line interface (CLI) or Representational
+State Transfer Application (REST API's).
+
+The management application runs on a Linux logical partition on a
+POWER8 or newer processor-based server that is virtualized by PowerVM.
+System configuration, maintenance, and control functions which
+traditionally require an HMC can be implemented in the management
+application using a combination of HMC to hypervisor interfaces and
+existing operating system methods. This tool provides a subset of the
+functions implemented by the HMC and enables basic partition configuration.
+The set of HMC to hypervisor messages supported by the management
+application component are passed to the hypervisor over a VMC interface,
+which is defined below.
+
+The VMC enables the management partition to provide basic partitioning
+functions:
+
+- Logical Partitioning Configuration
+- Start, and stop actions for individual partitions
+- Display of partition status
+- Management of virtual Ethernet
+- Management of virtual Storage
+- Basic system management
+
+Virtual Management Channel (VMC)
+--------------------------------
+
+A logical device, called the Virtual Management Channel (VMC), is defined
+for communicating between the management application and the hypervisor. It
+basically creates the pipes that enable virtualization management
+software. This device is presented to a designated management partition as
+a virtual device.
+
+This communication device uses Command/Response Queue (CRQ) and the
+Remote Direct Memory Access (RDMA) interfaces. A three-way handshake is
+defined that must take place to establish that both the hypervisor and
+management partition sides of the channel are running prior to
+sending/receiving any of the protocol messages.
+
+This driver also utilizes Transport Event CRQs. CRQ messages are sent
+when the hypervisor detects one of the peer partitions has abnormally
+terminated, or one side has called H_FREE_CRQ to close their CRQ.
+Two new classes of CRQ messages are introduced for the VMC device. VMC
+Administrative messages are used for each partition using the VMC to
+communicate capabilities to their partner. HMC Interface messages are used
+for the actual flow of HMC messages between the management partition and
+the hypervisor. As most HMC messages far exceed the size of a CRQ buffer,
+a virtual DMA (RMDA) of the HMC message data is done prior to each HMC
+Interface CRQ message. Only the management partition drives RDMA
+operations; hypervisors never directly cause the movement of message data.
+
+
+Terminology
+-----------
+RDMA
+        Remote Direct Memory Access is DMA transfer from the server to its
+        client or from the server to its partner partition. DMA refers
+        to both physical I/O to and from memory operations and to memory
+        to memory move operations.
+CRQ
+        Command/Response Queue a facility which is used to communicate
+        between partner partitions. Transport events which are signaled
+        from the hypervisor to partition are also reported in this queue.
+
+Example Management Partition VMC Driver Interface
+=================================================
+
+This section provides an example for the management application
+implementation where a device driver is used to interface to the VMC
+device. This driver consists of a new device, for example /dev/ibmvmc,
+which provides interfaces to open, close, read, write, and perform
+ioctl’s against the VMC device.
+
+VMC Interface Initialization
+----------------------------
+
+The device driver is responsible for initializing the VMC when the driver
+is loaded. It first creates and initializes the CRQ. Next, an exchange of
+VMC capabilities is performed to indicate the code version and number of
+resources available in both the management partition and the hypervisor.
+Finally, the hypervisor requests that the management partition create an
+initial pool of VMC buffers, one buffer for each possible HMC connection,
+which will be used for management application  session initialization.
+Prior to completion of this initialization sequence, the device returns
+EBUSY to open() calls. EIO is returned for all open() failures.
+
+::
+
+        Management Partition           Hypervisor
+                        CRQ INIT
+        ---------------------------------------->
+                  CRQ INIT COMPLETE
+        <----------------------------------------
+                     CAPABILITIES
+        ---------------------------------------->
+                CAPABILITIES RESPONSE
+        <----------------------------------------
+              ADD BUFFER (HMC IDX=0,1,..)         _
+        <----------------------------------------  |
+                 ADD BUFFER RESPONSE              | - Perform # HMCs Iterations
+        ----------------------------------------> -
+
+VMC Interface Open
+------------------
+
+After the basic VMC channel has been initialized, an HMC session level
+connection can be established. The application layer performs an open() to
+the VMC device and executes an ioctl() against it, indicating the HMC ID
+(32 bytes of data) for this session. If the VMC device is in an invalid
+state, EIO will be returned for the ioctl(). The device driver creates a
+new HMC session value (ranging from 1 to 255) and HMC index value (starting
+at index 0 and ranging to 254) for this HMC ID. The driver then does an
+RDMA of the HMC ID to the hypervisor, and then sends an Interface Open
+message to the hypervisor to establish the session over the VMC. After the
+hypervisor receives this information, it sends Add Buffer messages to the
+management partition to seed an initial pool of buffers for the new HMC
+connection. Finally, the hypervisor sends an Interface Open Response
+message, to indicate that it is ready for normal runtime messaging. The
+following illustrates this VMC flow:
+
+::
+
+        Management Partition             Hypervisor
+                     RDMA HMC ID
+        ---------------------------------------->
+                   Interface Open
+        ---------------------------------------->
+                     Add Buffer                  _
+        <----------------------------------------  |
+                 Add Buffer Response              | - Perform N Iterations
+        ----------------------------------------> -
+               Interface Open Response
+        <----------------------------------------
+
+VMC Interface Runtime
+---------------------
+
+During normal runtime, the management application and the hypervisor
+exchange HMC messages via the Signal VMC message and RDMA operations. When
+sending data to the hypervisor, the management application performs a
+write() to the VMC device, and the driver RDMA’s the data to the hypervisor
+and then sends a Signal Message. If a write() is attempted before VMC
+device buffers have been made available by the hypervisor, or no buffers
+are currently available, EBUSY is returned in response to the write(). A
+write() will return EIO for all other errors, such as an invalid device
+state. When the hypervisor sends a message to the management, the data is
+put into a VMC buffer and an Signal Message is sent to the VMC driver in
+the management partition. The driver RDMA’s the buffer into the partition
+and passes the data up to the appropriate management application via a
+read() to the VMC device. The read() request blocks if there is no buffer
+available to read. The management application may use select() to wait for
+the VMC device to become ready with data to read.
+
+::
+
+        Management Partition             Hypervisor
+                       MSG RDMA
+        ---------------------------------------->
+                       SIGNAL MSG
+        ---------------------------------------->
+                       SIGNAL MSG
+        <----------------------------------------
+                       MSG RDMA
+        <----------------------------------------
+
+VMC Interface Close
+-------------------
+
+HMC session level connections are closed by the management partition when
+the application layer performs a close() against the device. This action
+results in an Interface Close message flowing to the hypervisor, which
+causes the session to be terminated. The device driver must free any
+storage allocated for buffers for this HMC connection.
+
+::
+
+        Management Partition             Hypervisor
+                    INTERFACE CLOSE
+        ---------------------------------------->
+                INTERFACE CLOSE RESPONSE
+        <----------------------------------------
+
+Additional Information
+======================
+
+For more information on the documentation for CRQ Messages, VMC Messages,
+HMC interface Buffers, and signal messages please refer to the Linux on
+Power Architecture Platform Reference. Section F.
diff --git a/MAINTAINERS b/MAINTAINERS
index c7182d2..79969f9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6721,6 +6721,12 @@ L:       linux-s...@vger.kernel.org
 S:     Supported
 F:     drivers/scsi/ibmvscsi/ibmvfc*
 
+IBM Power Virtual Management Channel Driver
+M:     Bryant G. Ly <bryan...@linux.vnet.ibm.com>
+M:     Steven Royer <sero...@linux.vnet.ibm.com>
+S:     Supported
+F:     drivers/misc/ibmvmc.*
+
 IBM Power Virtual SCSI Device Drivers
 M:     Tyrel Datwyler <tyr...@linux.vnet.ibm.com>
 L:     linux-s...@vger.kernel.org
diff --git a/arch/powerpc/include/asm/hvcall.h 
b/arch/powerpc/include/asm/hvcall.h
index 2e2ddda..662c834 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -279,6 +279,7 @@
 #define H_GET_MPP_X            0x314
 #define H_SET_MODE             0x31C
 #define H_CLEAR_HPT            0x358
+#define H_REQUEST_VMC          0x360
 #define H_RESIZE_HPT_PREPARE   0x36C
 #define H_RESIZE_HPT_COMMIT    0x370
 #define H_REGISTER_PROC_TBL    0x37C
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 5d71300..3726eac 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -113,6 +113,20 @@ config IBM_ASM
          for information on the specific driver level and support statement
          for your IBM server.
 
+config IBMVMC
+       tristate "IBM Virtual Management Channel support"
+       depends on PPC_PSERIES
+       help
+         This is the IBM POWER Virtual Management Channel
+
+         This driver is to be used for the POWER Virtual
+         Management Channel virtual adapter on the PowerVM
+         platform. It provides both request/response and
+         async message support through the /dev/ibmvmc node.
+
+         To compile this driver as a module, choose M here: the
+         module will be called ibmvmc.
+
 config PHANTOM
        tristate "Sensable PHANToM (PCI)"
        depends on PCI
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 20be70c..af22bbc 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -4,6 +4,7 @@
 #
 
 obj-$(CONFIG_IBM_ASM)          += ibmasm/
+obj-$(CONFIG_IBMVMC)           += ibmvmc.o
 obj-$(CONFIG_AD525X_DPOT)      += ad525x_dpot.o
 obj-$(CONFIG_AD525X_DPOT_I2C)  += ad525x_dpot-i2c.o
 obj-$(CONFIG_AD525X_DPOT_SPI)  += ad525x_dpot-spi.o
diff --git a/drivers/misc/ibmvmc.c b/drivers/misc/ibmvmc.c
new file mode 100644
index 0000000..fb83d13
--- /dev/null
+++ b/drivers/misc/ibmvmc.c
@@ -0,0 +1,2418 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * IBM Power Systems Virtual Management Channel Support.
+ *
+ * Copyright (c) 2004, 2018 IBM Corp.
+ *   Dave Engebretsen engeb...@us.ibm.com
+ *   Steven Royer sero...@linux.vnet.ibm.com
+ *   Adam Reznechek adrez...@linux.vnet.ibm.com
+ *   Bryant G. Ly <bryan...@linux.vnet.ibm.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/major.h>
+#include <linux/string.h>
+#include <linux/fcntl.h>
+#include <linux/slab.h>
+#include <linux/poll.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/percpu.h>
+#include <linux/delay.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/miscdevice.h>
+#include <linux/sched/signal.h>
+
+#include <asm/byteorder.h>
+#include <asm/irq.h>
+#include <asm/vio.h>
+
+#include "ibmvmc.h"
+
+#define IBMVMC_DRIVER_VERSION "1.0"
+
+/*
+ * Static global variables
+ */
+static DECLARE_WAIT_QUEUE_HEAD(ibmvmc_read_wait);
+
+static const char ibmvmc_driver_name[] = "ibmvmc";
+
+static struct ibmvmc_struct ibmvmc;
+static struct ibmvmc_hmc hmcs[MAX_HMCS];
+static struct crq_server_adapter ibmvmc_adapter;
+
+static int ibmvmc_max_buf_pool_size = DEFAULT_BUF_POOL_SIZE;
+static int ibmvmc_max_hmcs = DEFAULT_HMCS;
+static int ibmvmc_max_mtu = DEFAULT_MTU;
+
+static inline long h_copy_rdma(s64 length, u64 sliobn, u64 slioba,
+                              u64 dliobn, u64 dlioba)
+{
+       long rc = 0;
+
+       /* Ensure all writes to source memory are visible before hcall */
+       dma_wmb();
+       pr_debug("ibmvmc: h_copy_rdma(0x%llx, 0x%llx, 0x%llx, 0x%llx, 0x%llx\n",
+                length, sliobn, slioba, dliobn, dlioba);
+       rc = plpar_hcall_norets(H_COPY_RDMA, length, sliobn, slioba,
+                               dliobn, dlioba);
+       pr_debug("ibmvmc: h_copy_rdma rc = 0x%lx\n", rc);
+
+       return rc;
+}
+
+static inline void h_free_crq(uint32_t unit_address)
+{
+       long rc = 0;
+
+       do {
+               if (H_IS_LONG_BUSY(rc))
+                       msleep(get_longbusy_msecs(rc));
+
+               rc = plpar_hcall_norets(H_FREE_CRQ, unit_address);
+       } while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
+}
+
+/**
+ * h_request_vmc: - request a hypervisor virtual management channel device
+ * @vmc_index: drc index of the vmc device created
+ *
+ * Requests the hypervisor create a new virtual management channel device,
+ * allowing this partition to send hypervisor virtualization control
+ * commands.
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static inline long h_request_vmc(u32 *vmc_index)
+{
+       long rc = 0;
+       unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+
+       do {
+               if (H_IS_LONG_BUSY(rc))
+                       msleep(get_longbusy_msecs(rc));
+
+               /* Call to request the VMC device from phyp */
+               rc = plpar_hcall(H_REQUEST_VMC, retbuf);
+               pr_debug("ibmvmc: %s rc = 0x%lx\n", __func__, rc);
+               *vmc_index = retbuf[0];
+       } while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
+
+       return rc;
+}
+
+/* routines for managing a command/response queue */
+/**
+ * ibmvmc_handle_event: - Interrupt handler for crq events
+ * @irq:        number of irq to handle, not used
+ * @dev_instance: crq_server_adapter that received interrupt
+ *
+ * Disables interrupts and schedules ibmvmc_task
+ *
+ * Always returns IRQ_HANDLED
+ */
+static irqreturn_t ibmvmc_handle_event(int irq, void *dev_instance)
+{
+       struct crq_server_adapter *adapter =
+               (struct crq_server_adapter *)dev_instance;
+
+       vio_disable_interrupts(to_vio_dev(adapter->dev));
+       tasklet_schedule(&adapter->work_task);
+
+       return IRQ_HANDLED;
+}
+
+/**
+ * ibmvmc_release_crq_queue - Release CRQ Queue
+ *
+ * @adapter:   crq_server_adapter struct
+ *
+ * Return:
+ *     0 - Success
+ *     Non-Zero - Failure
+ */
+static void ibmvmc_release_crq_queue(struct crq_server_adapter *adapter)
+{
+       struct vio_dev *vdev = to_vio_dev(adapter->dev);
+       struct crq_queue *queue = &adapter->queue;
+
+       free_irq(vdev->irq, (void *)adapter);
+       tasklet_kill(&adapter->work_task);
+
+       if (adapter->reset_task)
+               kthread_stop(adapter->reset_task);
+
+       h_free_crq(vdev->unit_address);
+       dma_unmap_single(adapter->dev,
+                        queue->msg_token,
+                        queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
+       free_page((unsigned long)queue->msgs);
+}
+
+/**
+ * ibmvmc_reset_crq_queue - Reset CRQ Queue
+ *
+ * @adapter:   crq_server_adapter struct
+ *
+ * This function calls h_free_crq and then calls H_REG_CRQ and does all the
+ * bookkeeping to get us back to where we can communicate.
+ *
+ * Return:
+ *     0 - Success
+ *     Non-Zero - Failure
+ */
+static int ibmvmc_reset_crq_queue(struct crq_server_adapter *adapter)
+{
+       struct vio_dev *vdev = to_vio_dev(adapter->dev);
+       struct crq_queue *queue = &adapter->queue;
+       int rc = 0;
+
+       /* Close the CRQ */
+       h_free_crq(vdev->unit_address);
+
+       /* Clean out the queue */
+       memset(queue->msgs, 0x00, PAGE_SIZE);
+       queue->cur = 0;
+
+       /* And re-open it again */
+       rc = plpar_hcall_norets(H_REG_CRQ,
+                               vdev->unit_address,
+                               queue->msg_token, PAGE_SIZE);
+       if (rc == 2)
+               /* Adapter is good, but other end is not ready */
+               dev_warn(adapter->dev, "Partner adapter not ready\n");
+       else if (rc != 0)
+               dev_err(adapter->dev, "couldn't register crq--rc 0x%x\n", rc);
+
+       return rc;
+}
+
+/**
+ * crq_queue_next_crq: - Returns the next entry in message queue
+ * @queue:      crq_queue to use
+ *
+ * Returns pointer to next entry in queue, or NULL if there are no new
+ * entried in the CRQ.
+ */
+static struct ibmvmc_crq_msg *crq_queue_next_crq(struct crq_queue *queue)
+{
+       struct ibmvmc_crq_msg *crq;
+       unsigned long flags;
+
+       spin_lock_irqsave(&queue->lock, flags);
+       crq = &queue->msgs[queue->cur];
+       if (crq->valid & 0x80) {
+               if (++queue->cur == queue->size)
+                       queue->cur = 0;
+
+               /* Ensure the read of the valid bit occurs before reading any
+                * other bits of the CRQ entry
+                */
+               dma_rmb();
+       } else {
+               crq = NULL;
+       }
+
+       spin_unlock_irqrestore(&queue->lock, flags);
+
+       return crq;
+}
+
+/**
+ * ibmvmc_send_crq - Send CRQ
+ *
+ * @adapter:   crq_server_adapter struct
+ * @word1:     Word1 Data field
+ * @word2:     Word2 Data field
+ *
+ * Return:
+ *     0 - Success
+ *     Non-Zero - Failure
+ */
+static long ibmvmc_send_crq(struct crq_server_adapter *adapter,
+                           u64 word1, u64 word2)
+{
+       struct vio_dev *vdev = to_vio_dev(adapter->dev);
+       long rc = 0;
+
+       dev_dbg(adapter->dev, "(0x%x, 0x%016llx, 0x%016llx)\n",
+               vdev->unit_address, word1, word2);
+
+       /*
+        * Ensure the command buffer is flushed to memory before handing it
+        * over to the other side to prevent it from fetching any stale data.
+        */
+       dma_wmb();
+       rc = plpar_hcall_norets(H_SEND_CRQ, vdev->unit_address, word1, word2);
+       dev_dbg(adapter->dev, "rc = 0x%lx\n", rc);
+
+       return rc;
+}
+
+/**
+ * alloc_dma_buffer - Create DMA Buffer
+ *
+ * @vdev:      vio_dev struct
+ * @size:      Size field
+ * @dma_handle:        DMA address field
+ *
+ * Allocates memory for the command queue and maps remote memory into an
+ * ioba.
+ *
+ * Returns a pointer to the buffer
+ */
+static void *alloc_dma_buffer(struct vio_dev *vdev, size_t size,
+                             dma_addr_t *dma_handle)
+{
+       /* allocate memory */
+       void *buffer = kzalloc(size, GFP_KERNEL);
+
+       if (!buffer) {
+               *dma_handle = 0;
+               return NULL;
+       }
+
+       /* DMA map */
+       *dma_handle = dma_map_single(&vdev->dev, buffer, size,
+                                    DMA_BIDIRECTIONAL);
+
+       if (dma_mapping_error(&vdev->dev, *dma_handle)) {
+               *dma_handle = 0;
+               kzfree(buffer);
+               return NULL;
+       }
+
+       return buffer;
+}
+
+/**
+ * free_dma_buffer - Free DMA Buffer
+ *
+ * @vdev:      vio_dev struct
+ * @size:      Size field
+ * @vaddr:     Address field
+ * @dma_handle:        DMA address field
+ *
+ * Releases memory for a command queue and unmaps mapped remote memory.
+ */
+static void free_dma_buffer(struct vio_dev *vdev, size_t size, void *vaddr,
+                           dma_addr_t dma_handle)
+{
+       /* DMA unmap */
+       dma_unmap_single(&vdev->dev, dma_handle, size, DMA_BIDIRECTIONAL);
+
+       /* deallocate memory */
+       kzfree(vaddr);
+}
+
+/**
+ * ibmvmc_get_valid_hmc_buffer - Retrieve Valid HMC Buffer
+ *
+ * @hmc_index: HMC Index Field
+ *
+ * Return:
+ *     Pointer to ibmvmc_buffer
+ */
+static struct ibmvmc_buffer *ibmvmc_get_valid_hmc_buffer(u8 hmc_index)
+{
+       struct ibmvmc_buffer *buffer;
+       struct ibmvmc_buffer *ret_buf = NULL;
+       unsigned long i;
+
+       if (hmc_index > ibmvmc.max_hmc_index)
+               return NULL;
+
+       buffer = hmcs[hmc_index].buffer;
+
+       for (i = 0; i < ibmvmc_max_buf_pool_size; i++) {
+               if (buffer[i].valid && buffer[i].free &&
+                   buffer[i].owner == VMC_BUF_OWNER_ALPHA) {
+                       buffer[i].free = 0;
+                       ret_buf = &buffer[i];
+                       break;
+               }
+       }
+
+       return ret_buf;
+}
+
+/**
+ * ibmvmc_get_free_hmc_buffer - Get Free HMC Buffer
+ *
+ * @adapter:   crq_server_adapter struct
+ * @hmc_index: Hmc Index field
+ *
+ * Return:
+ *     Pointer to ibmvmc_buffer
+ */
+static struct ibmvmc_buffer *ibmvmc_get_free_hmc_buffer(struct 
crq_server_adapter *adapter,
+                                                       u8 hmc_index)
+{
+       struct ibmvmc_buffer *buffer;
+       struct ibmvmc_buffer *ret_buf = NULL;
+       unsigned long i;
+
+       if (hmc_index > ibmvmc.max_hmc_index) {
+               dev_info(adapter->dev, "get_free_hmc_buffer: invalid 
hmc_index=0x%x\n",
+                        hmc_index);
+               return NULL;
+       }
+
+       buffer = hmcs[hmc_index].buffer;
+
+       for (i = 0; i < ibmvmc_max_buf_pool_size; i++) {
+               if (buffer[i].free &&
+                   buffer[i].owner == VMC_BUF_OWNER_ALPHA) {
+                       buffer[i].free = 0;
+                       ret_buf = &buffer[i];
+                       break;
+               }
+       }
+
+       return ret_buf;
+}
+
+/**
+ * ibmvmc_free_hmc_buffer - Free an HMC Buffer
+ *
+ * @hmc:       ibmvmc_hmc struct
+ * @buffer:    ibmvmc_buffer struct
+ *
+ */
+static void ibmvmc_free_hmc_buffer(struct ibmvmc_hmc *hmc,
+                                  struct ibmvmc_buffer *buffer)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&hmc->lock, flags);
+       buffer->free = 1;
+       spin_unlock_irqrestore(&hmc->lock, flags);
+}
+
+/**
+ * ibmvmc_count_hmc_buffers - Count HMC Buffers
+ *
+ * @hmc_index: HMC Index field
+ * @valid:     Valid number of buffers field
+ * @free:      Free number of buffers field
+ *
+ */
+static void ibmvmc_count_hmc_buffers(u8 hmc_index, unsigned int *valid,
+                                    unsigned int *free)
+{
+       struct ibmvmc_buffer *buffer;
+       unsigned long i;
+       unsigned long flags;
+
+       if (hmc_index > ibmvmc.max_hmc_index)
+               return;
+
+       if (!valid || !free)
+               return;
+
+       *valid = 0; *free = 0;
+
+       buffer = hmcs[hmc_index].buffer;
+       spin_lock_irqsave(&hmcs[hmc_index].lock, flags);
+
+       for (i = 0; i < ibmvmc_max_buf_pool_size; i++) {
+               if (buffer[i].valid) {
+                       *valid = *valid + 1;
+                       if (buffer[i].free)
+                               *free = *free + 1;
+               }
+       }
+
+       spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+}
+
+/**
+ * ibmvmc_get_free_hmc - Get Free HMC
+ *
+ * Return:
+ *     Pointer to an available HMC Connection
+ *     Null otherwise
+ */
+static struct ibmvmc_hmc *ibmvmc_get_free_hmc(void)
+{
+       unsigned long i;
+       unsigned long flags;
+
+       /*
+        * Find an available HMC connection.
+        */
+       for (i = 0; i <= ibmvmc.max_hmc_index; i++) {
+               spin_lock_irqsave(&hmcs[i].lock, flags);
+               if (hmcs[i].state == ibmhmc_state_free) {
+                       hmcs[i].index = i;
+                       hmcs[i].state = ibmhmc_state_initial;
+                       spin_unlock_irqrestore(&hmcs[i].lock, flags);
+                       return &hmcs[i];
+               }
+               spin_unlock_irqrestore(&hmcs[i].lock, flags);
+       }
+
+       return NULL;
+}
+
+/**
+ * ibmvmc_return_hmc - Return an HMC Connection
+ *
+ * @hmc:               ibmvmc_hmc struct
+ * @release_readers:   Number of readers connected to session
+ *
+ * This function releases the HMC connections back into the pool.
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static int ibmvmc_return_hmc(struct ibmvmc_hmc *hmc, bool release_readers)
+{
+       struct ibmvmc_buffer *buffer;
+       struct crq_server_adapter *adapter;
+       struct vio_dev *vdev;
+       unsigned long i;
+       unsigned long flags;
+
+       if (!hmc || !hmc->adapter)
+               return -EIO;
+
+       if (release_readers) {
+               if (hmc->file_session) {
+                       struct ibmvmc_file_session *session = hmc->file_session;
+
+                       session->valid = 0;
+                       wake_up_interruptible(&ibmvmc_read_wait);
+               }
+       }
+
+       adapter = hmc->adapter;
+       vdev = to_vio_dev(adapter->dev);
+
+       spin_lock_irqsave(&hmc->lock, flags);
+       hmc->index = 0;
+       hmc->state = ibmhmc_state_free;
+       hmc->queue_head = 0;
+       hmc->queue_tail = 0;
+       buffer = hmc->buffer;
+       for (i = 0; i < ibmvmc_max_buf_pool_size; i++) {
+               if (buffer[i].valid) {
+                       free_dma_buffer(vdev,
+                                       ibmvmc.max_mtu,
+                                       buffer[i].real_addr_local,
+                                       buffer[i].dma_addr_local);
+                       dev_dbg(adapter->dev, "Forgot buffer id 0x%lx\n", i);
+               }
+               memset(&buffer[i], 0, sizeof(struct ibmvmc_buffer));
+
+               hmc->queue_outbound_msgs[i] = VMC_INVALID_BUFFER_ID;
+       }
+
+       spin_unlock_irqrestore(&hmc->lock, flags);
+
+       return 0;
+}
+
+/**
+ * ibmvmc_send_open - Interface Open
+ * @buffer: Pointer to ibmvmc_buffer struct
+ * @hmc: Pointer to ibmvmc_hmc struct
+ *
+ * This command is sent by the management partition as the result of a
+ * management partition device request. It causes the hypervisor to
+ * prepare a set of data buffers for the management application connection
+ * indicated HMC idx. A unique HMC Idx would be used if multiple management
+ * applications running concurrently were desired. Before responding to this
+ * command, the hypervisor must provide the management partition with at
+ * least one of these new buffers via the Add Buffer. This indicates whether
+ * the messages are inbound or outbound from the hypervisor.
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static int ibmvmc_send_open(struct ibmvmc_buffer *buffer,
+                           struct ibmvmc_hmc *hmc)
+{
+       struct ibmvmc_crq_msg crq_msg;
+       struct crq_server_adapter *adapter;
+       __be64 *crq_as_u64 = (__be64 *)&crq_msg;
+       int rc = 0;
+
+       if (!hmc || !hmc->adapter)
+               return -EIO;
+
+       adapter = hmc->adapter;
+
+       dev_dbg(adapter->dev, "send_open: 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
+               (unsigned long)buffer->size, (unsigned long)adapter->liobn,
+               (unsigned long)buffer->dma_addr_local,
+               (unsigned long)adapter->riobn,
+               (unsigned long)buffer->dma_addr_remote);
+
+       rc = h_copy_rdma(buffer->size,
+                        adapter->liobn,
+                        buffer->dma_addr_local,
+                        adapter->riobn,
+                        buffer->dma_addr_remote);
+       if (rc) {
+               dev_err(adapter->dev, "Error: In send_open, h_copy_rdma rc 
0x%x\n",
+                       rc);
+               return -EIO;
+       }
+
+       hmc->state = ibmhmc_state_opening;
+
+       crq_msg.valid = 0x80;
+       crq_msg.type = VMC_MSG_OPEN;
+       crq_msg.status = 0;
+       crq_msg.var1.rsvd = 0;
+       crq_msg.hmc_session = hmc->session;
+       crq_msg.hmc_index = hmc->index;
+       crq_msg.var2.buffer_id = cpu_to_be16(buffer->id);
+       crq_msg.rsvd = 0;
+       crq_msg.var3.rsvd = 0;
+
+       ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+                       be64_to_cpu(crq_as_u64[1]));
+
+       return rc;
+}
+
+/**
+ * ibmvmc_send_close - Interface Close
+ * @hmc: Pointer to ibmvmc_hmc struct
+ *
+ * This command is sent by the management partition to terminate a
+ * management application to hypervisor connection. When this command is
+ * sent, the management partition has quiesced all I/O operations to all
+ * buffers associated with this management application connection, and
+ * has freed any storage for these buffers.
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static int ibmvmc_send_close(struct ibmvmc_hmc *hmc)
+{
+       struct ibmvmc_crq_msg crq_msg;
+       struct crq_server_adapter *adapter;
+       __be64 *crq_as_u64 = (__be64 *)&crq_msg;
+       int rc = 0;
+
+       if (!hmc || !hmc->adapter)
+               return -EIO;
+
+       adapter = hmc->adapter;
+
+       dev_info(adapter->dev, "CRQ send: close\n");
+
+       crq_msg.valid = 0x80;
+       crq_msg.type = VMC_MSG_CLOSE;
+       crq_msg.status = 0;
+       crq_msg.var1.rsvd = 0;
+       crq_msg.hmc_session = hmc->session;
+       crq_msg.hmc_index = hmc->index;
+       crq_msg.var2.rsvd = 0;
+       crq_msg.rsvd = 0;
+       crq_msg.var3.rsvd = 0;
+
+       ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+                       be64_to_cpu(crq_as_u64[1]));
+
+       return rc;
+}
+
+/**
+ * ibmvmc_send_capabilities - Send VMC Capabilities
+ *
+ * @adapter:   crq_server_adapter struct
+ *
+ * The capabilities message is an administrative message sent after the CRQ
+ * initialization sequence of messages and is used to exchange VMC capabilities
+ * between the management partition and the hypervisor. The management
+ * partition must send this message and the hypervisor must respond with VMC
+ * capabilities Response message before HMC interface message can begin. Any
+ * HMC interface messages received before the exchange of capabilities has
+ * complete are dropped.
+ *
+ * Return:
+ *     0 - Success
+ */
+static int ibmvmc_send_capabilities(struct crq_server_adapter *adapter)
+{
+       struct ibmvmc_admin_crq_msg crq_msg;
+       __be64 *crq_as_u64 = (__be64 *)&crq_msg;
+
+       dev_dbg(adapter->dev, "ibmvmc: CRQ send: capabilities\n");
+       crq_msg.valid = 0x80;
+       crq_msg.type = VMC_MSG_CAP;
+       crq_msg.status = 0;
+       crq_msg.rsvd[0] = 0;
+       crq_msg.rsvd[1] = 0;
+       crq_msg.max_hmc = ibmvmc_max_hmcs;
+       crq_msg.max_mtu = cpu_to_be32(ibmvmc_max_mtu);
+       crq_msg.pool_size = cpu_to_be16(ibmvmc_max_buf_pool_size);
+       crq_msg.crq_size = cpu_to_be16(adapter->queue.size);
+       crq_msg.version = cpu_to_be16(IBMVMC_PROTOCOL_VERSION);
+
+       ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+                       be64_to_cpu(crq_as_u64[1]));
+
+       ibmvmc.state = ibmvmc_state_capabilities;
+
+       return 0;
+}
+
+/**
+ * ibmvmc_send_add_buffer_resp - Add Buffer Response
+ *
+ * @adapter:   crq_server_adapter struct
+ * @status:    Status field
+ * @hmc_session: HMC Session field
+ * @hmc_index: HMC Index field
+ * @buffer_id: Buffer Id field
+ *
+ * This command is sent by the management partition to the hypervisor in
+ * response to the Add Buffer message. The Status field indicates the result of
+ * the command.
+ *
+ * Return:
+ *     0 - Success
+ */
+static int ibmvmc_send_add_buffer_resp(struct crq_server_adapter *adapter,
+                                      u8 status, u8 hmc_session,
+                                      u8 hmc_index, u16 buffer_id)
+{
+       struct ibmvmc_crq_msg crq_msg;
+       __be64 *crq_as_u64 = (__be64 *)&crq_msg;
+
+       dev_dbg(adapter->dev, "CRQ send: add_buffer_resp\n");
+       crq_msg.valid = 0x80;
+       crq_msg.type = VMC_MSG_ADD_BUF_RESP;
+       crq_msg.status = status;
+       crq_msg.var1.rsvd = 0;
+       crq_msg.hmc_session = hmc_session;
+       crq_msg.hmc_index = hmc_index;
+       crq_msg.var2.buffer_id = cpu_to_be16(buffer_id);
+       crq_msg.rsvd = 0;
+       crq_msg.var3.rsvd = 0;
+
+       ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+                       be64_to_cpu(crq_as_u64[1]));
+
+       return 0;
+}
+
+/**
+ * ibmvmc_send_rem_buffer_resp - Remove Buffer Response
+ *
+ * @adapter:   crq_server_adapter struct
+ * @status:    Status field
+ * @hmc_session: HMC Session field
+ * @hmc_index: HMC Index field
+ * @buffer_id: Buffer Id field
+ *
+ * This command is sent by the management partition to the hypervisor in
+ * response to the Remove Buffer message. The Buffer ID field indicates
+ * which buffer the management partition selected to remove. The Status
+ * field indicates the result of the command.
+ *
+ * Return:
+ *     0 - Success
+ */
+static int ibmvmc_send_rem_buffer_resp(struct crq_server_adapter *adapter,
+                                      u8 status, u8 hmc_session,
+                                      u8 hmc_index, u16 buffer_id)
+{
+       struct ibmvmc_crq_msg crq_msg;
+       __be64 *crq_as_u64 = (__be64 *)&crq_msg;
+
+       dev_dbg(adapter->dev, "CRQ send: rem_buffer_resp\n");
+       crq_msg.valid = 0x80;
+       crq_msg.type = VMC_MSG_REM_BUF_RESP;
+       crq_msg.status = status;
+       crq_msg.var1.rsvd = 0;
+       crq_msg.hmc_session = hmc_session;
+       crq_msg.hmc_index = hmc_index;
+       crq_msg.var2.buffer_id = cpu_to_be16(buffer_id);
+       crq_msg.rsvd = 0;
+       crq_msg.var3.rsvd = 0;
+
+       ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+                       be64_to_cpu(crq_as_u64[1]));
+
+       return 0;
+}
+
+/**
+ * ibmvmc_send_msg - Signal Message
+ *
+ * @adapter:   crq_server_adapter struct
+ * @buffer:    ibmvmc_buffer struct
+ * @hmc:       ibmvmc_hmc struct
+ * @msg_length:        message length field
+ *
+ * This command is sent between the management partition and the hypervisor
+ * in order to signal the arrival of an HMC protocol message. The command
+ * can be sent by both the management partition and the hypervisor. It is
+ * used for all traffic between the management application and the hypervisor,
+ * regardless of who initiated the communication.
+ *
+ * There is no response to this message.
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static int ibmvmc_send_msg(struct crq_server_adapter *adapter,
+                          struct ibmvmc_buffer *buffer,
+                          struct ibmvmc_hmc *hmc, int msg_len)
+{
+       struct ibmvmc_crq_msg crq_msg;
+       __be64 *crq_as_u64 = (__be64 *)&crq_msg;
+       int rc = 0;
+
+       dev_dbg(adapter->dev, "CRQ send: rdma to HV\n");
+       rc = h_copy_rdma(msg_len,
+                        adapter->liobn,
+                        buffer->dma_addr_local,
+                        adapter->riobn,
+                        buffer->dma_addr_remote);
+       if (rc) {
+               dev_err(adapter->dev, "Error in send_msg, h_copy_rdma rc 
0x%x\n",
+                       rc);
+               return rc;
+       }
+
+       crq_msg.valid = 0x80;
+       crq_msg.type = VMC_MSG_SIGNAL;
+       crq_msg.status = 0;
+       crq_msg.var1.rsvd = 0;
+       crq_msg.hmc_session = hmc->session;
+       crq_msg.hmc_index = hmc->index;
+       crq_msg.var2.buffer_id = cpu_to_be16(buffer->id);
+       crq_msg.var3.msg_len = cpu_to_be32(msg_len);
+       dev_dbg(adapter->dev, "CRQ send: msg to HV 0x%llx 0x%llx\n",
+               be64_to_cpu(crq_as_u64[0]), be64_to_cpu(crq_as_u64[1]));
+
+       buffer->owner = VMC_BUF_OWNER_HV;
+       ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+                       be64_to_cpu(crq_as_u64[1]));
+
+       return rc;
+}
+
+/**
+ * ibmvmc_open - Open Session
+ *
+ * @inode:     inode struct
+ * @file:      file struct
+ *
+ * Return:
+ *     0 - Success
+ */
+static int ibmvmc_open(struct inode *inode, struct file *file)
+{
+       struct ibmvmc_file_session *session;
+       int rc = 0;
+
+       pr_debug("%s: inode = 0x%lx, file = 0x%lx, state = 0x%x\n", __func__,
+                (unsigned long)inode, (unsigned long)file,
+                ibmvmc.state);
+
+       session = kzalloc(sizeof(*session), GFP_KERNEL);
+       session->file = file;
+       file->private_data = session;
+
+       return rc;
+}
+
+/**
+ * ibmvmc_close - Close Session
+ *
+ * @inode:     inode struct
+ * @file:      file struct
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static int ibmvmc_close(struct inode *inode, struct file *file)
+{
+       struct ibmvmc_file_session *session;
+       struct ibmvmc_hmc *hmc;
+       int rc = 0;
+       unsigned long flags;
+
+       pr_debug("%s: file = 0x%lx, state = 0x%x\n", __func__,
+                (unsigned long)file, ibmvmc.state);
+
+       session = file->private_data;
+       if (!session)
+               return -EIO;
+
+       hmc = session->hmc;
+       if (hmc) {
+               if (!hmc->adapter)
+                       return -EIO;
+
+               if (ibmvmc.state == ibmvmc_state_failed) {
+                       dev_warn(hmc->adapter->dev, "close: state_failed\n");
+                       return -EIO;
+               }
+
+               spin_lock_irqsave(&hmc->lock, flags);
+               if (hmc->state >= ibmhmc_state_opening) {
+                       rc = ibmvmc_send_close(hmc);
+                       if (rc)
+                               dev_warn(hmc->adapter->dev, "close: send_close 
failed.\n");
+               }
+               spin_unlock_irqrestore(&hmc->lock, flags);
+       }
+
+       kzfree(session);
+
+       return rc;
+}
+
+/**
+ * ibmvmc_read - Read
+ *
+ * @file:      file struct
+ * @buf:       Character buffer
+ * @nbytes:    Size in bytes
+ * @ppos:      Offset
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static ssize_t ibmvmc_read(struct file *file, char *buf, size_t nbytes,
+                          loff_t *ppos)
+{
+       struct ibmvmc_file_session *session;
+       struct ibmvmc_hmc *hmc;
+       struct crq_server_adapter *adapter;
+       struct ibmvmc_buffer *buffer;
+       ssize_t n;
+       ssize_t retval = 0;
+       unsigned long flags;
+       DEFINE_WAIT(wait);
+
+       pr_debug("ibmvmc: read: file = 0x%lx, buf = 0x%lx, nbytes = 0x%lx\n",
+                (unsigned long)file, (unsigned long)buf,
+                (unsigned long)nbytes);
+
+       if (nbytes == 0)
+               return 0;
+
+       if (nbytes > ibmvmc.max_mtu) {
+               pr_warn("ibmvmc: read: nbytes invalid 0x%x\n",
+                       (unsigned int)nbytes);
+               return -EINVAL;
+       }
+
+       session = file->private_data;
+       if (!session) {
+               pr_warn("ibmvmc: read: no session\n");
+               return -EIO;
+       }
+
+       hmc = session->hmc;
+       if (!hmc) {
+               pr_warn("ibmvmc: read: no hmc\n");
+               return -EIO;
+       }
+
+       adapter = hmc->adapter;
+       if (!adapter) {
+               pr_warn("ibmvmc: read: no adapter\n");
+               return -EIO;
+       }
+
+       do {
+               prepare_to_wait(&ibmvmc_read_wait, &wait, TASK_INTERRUPTIBLE);
+
+               spin_lock_irqsave(&hmc->lock, flags);
+               if (hmc->queue_tail != hmc->queue_head)
+                       /* Data is available */
+                       break;
+
+               spin_unlock_irqrestore(&hmc->lock, flags);
+
+               if (!session->valid) {
+                       retval = -EBADFD;
+                       goto out;
+               }
+               if (file->f_flags & O_NONBLOCK) {
+                       retval = -EAGAIN;
+                       goto out;
+               }
+
+               schedule();
+
+               if (signal_pending(current)) {
+                       retval = -ERESTARTSYS;
+                       goto out;
+               }
+       } while (1);
+
+       buffer = &(hmc->buffer[hmc->queue_outbound_msgs[hmc->queue_tail]]);
+       hmc->queue_tail++;
+       if (hmc->queue_tail == ibmvmc_max_buf_pool_size)
+               hmc->queue_tail = 0;
+       spin_unlock_irqrestore(&hmc->lock, flags);
+
+       nbytes = min_t(size_t, nbytes, buffer->msg_len);
+       n = copy_to_user((void *)buf, buffer->real_addr_local, nbytes);
+       dev_dbg(adapter->dev, "read: copy to user nbytes = 0x%lx.\n", nbytes);
+       ibmvmc_free_hmc_buffer(hmc, buffer);
+       retval = nbytes;
+
+       if (n) {
+               dev_warn(adapter->dev, "read: copy to user failed.\n");
+               retval = -EFAULT;
+       }
+
+ out:
+       finish_wait(&ibmvmc_read_wait, &wait);
+       dev_dbg(adapter->dev, "read: out %ld\n", retval);
+       return retval;
+}
+
+/**
+ * ibmvmc_poll - Poll
+ *
+ * @file:      file struct
+ * @wait:      Poll Table
+ *
+ * Return:
+ *     poll.h return values
+ */
+static unsigned int ibmvmc_poll(struct file *file, poll_table *wait)
+{
+       struct ibmvmc_file_session *session;
+       struct ibmvmc_hmc *hmc;
+       unsigned int mask = 0;
+
+       session = file->private_data;
+       if (!session)
+               return 0;
+
+       hmc = session->hmc;
+       if (!hmc)
+               return 0;
+
+       poll_wait(file, &ibmvmc_read_wait, wait);
+
+       if (hmc->queue_head != hmc->queue_tail)
+               mask |= POLLIN | POLLRDNORM;
+
+       return mask;
+}
+
+/**
+ * ibmvmc_write - Write
+ *
+ * @file:      file struct
+ * @buf:       Character buffer
+ * @count:     Count field
+ * @ppos:      Offset
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static ssize_t ibmvmc_write(struct file *file, const char *buffer,
+                           size_t count, loff_t *ppos)
+{
+       struct ibmvmc_buffer *vmc_buffer;
+       struct ibmvmc_file_session *session;
+       struct crq_server_adapter *adapter;
+       struct ibmvmc_hmc *hmc;
+       unsigned char *buf;
+       unsigned long flags;
+       size_t bytes;
+       const char *p = buffer;
+       size_t c = count;
+       int ret = 0;
+
+       session = file->private_data;
+       if (!session)
+               return -EIO;
+
+       hmc = session->hmc;
+       if (!hmc)
+               return -EIO;
+
+       spin_lock_irqsave(&hmc->lock, flags);
+       if (hmc->state == ibmhmc_state_free) {
+               /* HMC connection is not valid (possibly was reset under us). */
+               ret = -EIO;
+               goto out;
+       }
+
+       adapter = hmc->adapter;
+       if (!adapter) {
+               ret = -EIO;
+               goto out;
+       }
+
+       if (count > ibmvmc.max_mtu) {
+               dev_warn(adapter->dev, "invalid buffer size 0x%lx\n",
+                        (unsigned long)count);
+               ret = -EIO;
+               goto out;
+       }
+
+       /* Waiting for the open resp message to the ioctl(1) - retry */
+       if (hmc->state == ibmhmc_state_opening) {
+               ret = -EBUSY;
+               goto out;
+       }
+
+       /* Make sure the ioctl() was called & the open msg sent, and that
+        * the HMC connection has not failed.
+        */
+       if (hmc->state != ibmhmc_state_ready) {
+               ret = -EIO;
+               goto out;
+       }
+
+       vmc_buffer = ibmvmc_get_valid_hmc_buffer(hmc->index);
+       if (!vmc_buffer) {
+               /* No buffer available for the msg send, or we have not yet
+                * completed the open/open_resp sequence.  Retry until this is
+                * complete.
+                */
+               ret = -EBUSY;
+               goto out;
+       }
+       if (!vmc_buffer->real_addr_local) {
+               dev_err(adapter->dev, "no buffer storage assigned\n");
+               ret = -EIO;
+               goto out;
+       }
+       buf = vmc_buffer->real_addr_local;
+
+       while (c > 0) {
+               bytes = min_t(size_t, c, vmc_buffer->size);
+
+               bytes -= copy_from_user(buf, p, bytes);
+               if (!bytes) {
+                       ret = -EFAULT;
+                       goto out;
+               }
+               c -= bytes;
+               p += bytes;
+       }
+       if (p == buffer)
+               goto out;
+
+       file->f_path.dentry->d_inode->i_mtime = current_time(file_inode(file));
+       mark_inode_dirty(file->f_path.dentry->d_inode);
+
+       dev_dbg(adapter->dev, "write: file = 0x%lx, count = 0x%lx\n",
+               (unsigned long)file, (unsigned long)count);
+
+       ibmvmc_send_msg(adapter, vmc_buffer, hmc, count);
+       ret = p - buffer;
+ out:
+       spin_unlock_irqrestore(&hmc->lock, flags);
+       return (ssize_t)(ret);
+}
+
+/**
+ * ibmvmc_setup_hmc - Setup the HMC
+ *
+ * @session:   ibmvmc_file_session struct
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static long ibmvmc_setup_hmc(struct ibmvmc_file_session *session)
+{
+       struct ibmvmc_hmc *hmc;
+       unsigned int valid, free, index;
+
+       if (ibmvmc.state == ibmvmc_state_failed) {
+               pr_warn("ibmvmc: Reserve HMC: state_failed\n");
+               return -EIO;
+       }
+
+       if (ibmvmc.state < ibmvmc_state_ready) {
+               pr_warn("ibmvmc: Reserve HMC: not state_ready\n");
+               return -EAGAIN;
+       }
+
+       /* Device is busy until capabilities have been exchanged and we
+        * have a generic buffer for each possible HMC connection.
+        */
+       for (index = 0; index <= ibmvmc.max_hmc_index; index++) {
+               valid = 0;
+               ibmvmc_count_hmc_buffers(index, &valid, &free);
+               if (valid == 0) {
+                       pr_warn("ibmvmc: buffers not ready for index %d\n",
+                               index);
+                       return -ENOBUFS;
+               }
+       }
+
+       /* Get an hmc object, and transition to ibmhmc_state_initial */
+       hmc = ibmvmc_get_free_hmc();
+       if (!hmc) {
+               pr_warn("%s: free hmc not found\n", __func__);
+               return -EBUSY;
+       }
+
+       hmc->session = hmc->session + 1;
+       if (hmc->session == 0xff)
+               hmc->session = 1;
+
+       session->hmc = hmc;
+       hmc->adapter = &ibmvmc_adapter;
+       hmc->file_session = session;
+       session->valid = 1;
+
+       return 0;
+}
+
+/**
+ * ibmvmc_ioctl_sethmcid - IOCTL Set HMC ID
+ *
+ * @session:   ibmvmc_file_session struct
+ * @new_hmc_id:        HMC id field
+ *
+ * IOCTL command to setup the hmc id
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static long ibmvmc_ioctl_sethmcid(struct ibmvmc_file_session *session,
+                                 unsigned char __user *new_hmc_id)
+{
+       struct ibmvmc_hmc *hmc;
+       struct ibmvmc_buffer *buffer;
+       size_t bytes;
+       char print_buffer[HMC_ID_LEN + 1];
+       unsigned long flags;
+       long rc = 0;
+
+       /* Reserve HMC session */
+       hmc = session->hmc;
+       if (!hmc) {
+               rc = ibmvmc_setup_hmc(session);
+               if (rc)
+                       return rc;
+
+               hmc = session->hmc;
+               if (!hmc) {
+                       pr_err("ibmvmc: setup_hmc success but no hmc\n");
+                       return -EIO;
+               }
+       }
+
+       if (hmc->state != ibmhmc_state_initial) {
+               pr_warn("ibmvmc: sethmcid: invalid state to send open 0x%x\n",
+                       hmc->state);
+               return -EIO;
+       }
+
+       bytes = copy_from_user(hmc->hmc_id, new_hmc_id, HMC_ID_LEN);
+       if (bytes)
+               return -EFAULT;
+
+       /* Send Open Session command */
+       spin_lock_irqsave(&hmc->lock, flags);
+       buffer = ibmvmc_get_valid_hmc_buffer(hmc->index);
+       spin_unlock_irqrestore(&hmc->lock, flags);
+
+       if (!buffer || !buffer->real_addr_local) {
+               pr_warn("ibmvmc: sethmcid: no buffer available\n");
+               return -EIO;
+       }
+
+       /* Make sure buffer is NULL terminated before trying to print it */
+       memset(print_buffer, 0, HMC_ID_LEN + 1);
+       strncpy(print_buffer, hmc->hmc_id, HMC_ID_LEN);
+       pr_info("ibmvmc: sethmcid: Set HMC ID: \"%s\"\n", print_buffer);
+
+       memcpy(buffer->real_addr_local, hmc->hmc_id, HMC_ID_LEN);
+       /* RDMA over ID, send open msg, change state to ibmhmc_state_opening */
+       rc = ibmvmc_send_open(buffer, hmc);
+
+       return rc;
+}
+
+/**
+ * ibmvmc_ioctl_query - IOCTL Query
+ *
+ * @session:   ibmvmc_file_session struct
+ * @ret_struct:        ibmvmc_query_struct
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static long ibmvmc_ioctl_query(struct ibmvmc_file_session *session,
+                              struct ibmvmc_query_struct __user *ret_struct)
+{
+       struct ibmvmc_query_struct query_struct;
+       size_t bytes;
+
+       memset(&query_struct, 0, sizeof(query_struct));
+       query_struct.have_vmc = (ibmvmc.state > ibmvmc_state_initial);
+       query_struct.state = ibmvmc.state;
+       query_struct.vmc_drc_index = ibmvmc.vmc_drc_index;
+
+       bytes = copy_to_user(ret_struct, &query_struct,
+                            sizeof(query_struct));
+       if (bytes)
+               return -EFAULT;
+
+       return 0;
+}
+
+/**
+ * ibmvmc_ioctl_requestvmc - IOCTL Request VMC
+ *
+ * @session:   ibmvmc_file_session struct
+ * @ret_vmc_index:     VMC Index
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static long ibmvmc_ioctl_requestvmc(struct ibmvmc_file_session *session,
+                                   u32 __user *ret_vmc_index)
+{
+       /* TODO: (adreznec) Add locking to control multiple process access */
+       size_t bytes;
+       long rc;
+       u32 vmc_drc_index;
+
+       /* Call to request the VMC device from phyp*/
+       rc = h_request_vmc(&vmc_drc_index);
+       pr_debug("ibmvmc: requestvmc: H_REQUEST_VMC rc = 0x%lx\n", rc);
+
+       if (rc == H_SUCCESS) {
+               rc = 0;
+       } else if (rc == H_FUNCTION) {
+               pr_err("ibmvmc: requestvmc: h_request_vmc not supported\n");
+               return -EPERM;
+       } else if (rc == H_AUTHORITY) {
+               pr_err("ibmvmc: requestvmc: hypervisor denied vmc request\n");
+               return -EPERM;
+       } else if (rc == H_HARDWARE) {
+               pr_err("ibmvmc: requestvmc: hypervisor hardware fault\n");
+               return -EIO;
+       } else if (rc == H_RESOURCE) {
+               pr_err("ibmvmc: requestvmc: vmc resource unavailable\n");
+               return -ENODEV;
+       } else if (rc == H_NOT_AVAILABLE) {
+               pr_err("ibmvmc: requestvmc: system cannot be vmc managed\n");
+               return -EPERM;
+       } else if (rc == H_PARAMETER) {
+               pr_err("ibmvmc: requestvmc: invalid parameter\n");
+               return -EINVAL;
+       }
+
+       /* Success, set the vmc index in global struct */
+       ibmvmc.vmc_drc_index = vmc_drc_index;
+
+       bytes = copy_to_user(ret_vmc_index, &vmc_drc_index,
+                            sizeof(*ret_vmc_index));
+       if (bytes) {
+               pr_warn("ibmvmc: requestvmc: copy to user failed.\n");
+               return -EFAULT;
+       }
+       return rc;
+}
+
+/**
+ * ibmvmc_ioctl - IOCTL
+ *
+ * @session:   ibmvmc_file_session struct
+ * @cmd:       cmd field
+ * @arg:       Argument field
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static long ibmvmc_ioctl(struct file *file,
+                        unsigned int cmd, unsigned long arg)
+{
+       struct ibmvmc_file_session *session = file->private_data;
+
+       pr_debug("ibmvmc: ioctl file=0x%lx, cmd=0x%x, arg=0x%lx, ses=0x%lx\n",
+                (unsigned long)file, cmd, arg,
+                (unsigned long)session);
+
+       if (!session) {
+               pr_warn("ibmvmc: ioctl: no session\n");
+               return -EIO;
+       }
+
+       switch (cmd) {
+       case VMC_IOCTL_SETHMCID:
+               return ibmvmc_ioctl_sethmcid(session,
+                       (unsigned char __user *)arg);
+       case VMC_IOCTL_QUERY:
+               return ibmvmc_ioctl_query(session,
+                       (struct ibmvmc_query_struct __user *)arg);
+       case VMC_IOCTL_REQUESTVMC:
+               return ibmvmc_ioctl_requestvmc(session,
+                       (unsigned int __user *)arg);
+       default:
+               pr_warn("ibmvmc: unknown ioctl 0x%x\n", cmd);
+               return -EINVAL;
+       }
+}
+
+static const struct file_operations ibmvmc_fops = {
+       .owner          = THIS_MODULE,
+       .read           = ibmvmc_read,
+       .write          = ibmvmc_write,
+       .poll           = ibmvmc_poll,
+       .unlocked_ioctl = ibmvmc_ioctl,
+       .open           = ibmvmc_open,
+       .release        = ibmvmc_close,
+};
+
+/**
+ * ibmvmc_add_buffer - Add Buffer
+ *
+ * @adapter: crq_server_adapter struct
+ * @crq:       ibmvmc_crq_msg struct
+ *
+ * This message transfers a buffer from hypervisor ownership to management
+ * partition ownership. The LIOBA is obtained from the virtual TCE table
+ * associated with the hypervisor side of the VMC device, and points to a
+ * buffer of size MTU (as established in the capabilities exchange).
+ *
+ * Typical flow for ading buffers:
+ * 1. A new management application connection is opened by the management
+ *     partition.
+ * 2. The hypervisor assigns new buffers for the traffic associated with
+ *     that connection.
+ * 3. The hypervisor sends VMC Add Buffer messages to the management
+ *     partition, informing it of the new buffers.
+ * 4. The hypervisor sends an HMC protocol message (to the management
+ *     application) notifying it of the new buffers. This informs the
+ *     application that it has buffers available for sending HMC
+ *     commands.
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static int ibmvmc_add_buffer(struct crq_server_adapter *adapter,
+                            struct ibmvmc_crq_msg *crq)
+{
+       struct ibmvmc_buffer *buffer;
+       u8 hmc_index;
+       u8 hmc_session;
+       u16 buffer_id;
+       unsigned long flags;
+       int rc = 0;
+
+       if (!crq)
+               return -1;
+
+       hmc_session = crq->hmc_session;
+       hmc_index = crq->hmc_index;
+       buffer_id = be16_to_cpu(crq->var2.buffer_id);
+
+       if (hmc_index > ibmvmc.max_hmc_index) {
+               dev_err(adapter->dev, "add_buffer: invalid hmc_index = 0x%x\n",
+                       hmc_index);
+               ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_HMC_INDEX,
+                                           hmc_session, hmc_index, buffer_id);
+               return -1;
+       }
+
+       if (buffer_id >= ibmvmc.max_buffer_pool_size) {
+               dev_err(adapter->dev, "add_buffer: invalid buffer_id = 0x%x\n",
+                       buffer_id);
+               ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_BUFFER_ID,
+                                           hmc_session, hmc_index, buffer_id);
+               return -1;
+       }
+
+       spin_lock_irqsave(&hmcs[hmc_index].lock, flags);
+       buffer = &hmcs[hmc_index].buffer[buffer_id];
+
+       if (buffer->real_addr_local || buffer->dma_addr_local) {
+               dev_warn(adapter->dev, "add_buffer: already allocated id = 
0x%lx\n",
+                        (unsigned long)buffer_id);
+               spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+               ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_BUFFER_ID,
+                                           hmc_session, hmc_index, buffer_id);
+               return -1;
+       }
+
+       buffer->real_addr_local = alloc_dma_buffer(to_vio_dev(adapter->dev),
+                                                  ibmvmc.max_mtu,
+                                                  &buffer->dma_addr_local);
+
+       if (!buffer->real_addr_local) {
+               dev_err(adapter->dev, "add_buffer: alloc_dma_buffer failed.\n");
+               spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+               ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INTERFACE_FAILURE,
+                                           hmc_session, hmc_index, buffer_id);
+               return -1;
+       }
+
+       buffer->dma_addr_remote = be32_to_cpu(crq->var3.lioba);
+       buffer->size = ibmvmc.max_mtu;
+       buffer->owner = crq->var1.owner;
+       buffer->free = 1;
+       /* Must ensure valid==1 is observable only after all other fields are */
+       dma_wmb();
+       buffer->valid = 1;
+       buffer->id = buffer_id;
+
+       dev_dbg(adapter->dev, "add_buffer: successfully added a buffer:\n");
+       dev_dbg(adapter->dev, "   index: %d, session: %d, buffer: 0x%x, owner: 
%d\n",
+               hmc_index, hmc_session, buffer_id, buffer->owner);
+       dev_dbg(adapter->dev, "   local: 0x%x, remote: 0x%x\n",
+               (u32)buffer->dma_addr_local,
+               (u32)buffer->dma_addr_remote);
+       spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+
+       ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_SUCCESS, hmc_session,
+                                   hmc_index, buffer_id);
+
+       return rc;
+}
+
+/**
+ * ibmvmc_rem_buffer - Remove Buffer
+ *
+ * @adapter: crq_server_adapter struct
+ * @crq:       ibmvmc_crq_msg struct
+ *
+ * This message requests an HMC buffer to be transferred from management
+ * partition ownership to hypervisor ownership. The management partition may
+ * not be able to satisfy the request at a particular point in time if all its
+ * buffers are in use. The management partition requires a depth of at least
+ * one inbound buffer to allow management application commands to flow to the
+ * hypervisor. It is, therefore, an interface error for the hypervisor to
+ * attempt to remove the management partition's last buffer.
+ *
+ * The hypervisor is expected to manage buffer usage with the management
+ * application directly and inform the management partition when buffers may be
+ * removed. The typical flow for removing buffers:
+ *
+ * 1. The management application no longer needs a communication path to a
+ *     particular hypervisor function. That function is closed.
+ * 2. The hypervisor and the management application quiesce all traffic to that
+ *     function. The hypervisor requests a reduction in buffer pool size.
+ * 3. The management application acknowledges the reduction in buffer pool 
size.
+ * 4. The hypervisor sends a Remove Buffer message to the management partition,
+ *     informing it of the reduction in buffers.
+ * 5. The management partition verifies it can remove the buffer. This is
+ *     possible if buffers have been quiesced.
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+/*
+ * The hypervisor requested that we pick an unused buffer, and return it.
+ * Before sending the buffer back, we free any storage associated with the
+ * buffer.
+ */
+static int ibmvmc_rem_buffer(struct crq_server_adapter *adapter,
+                            struct ibmvmc_crq_msg *crq)
+{
+       struct ibmvmc_buffer *buffer;
+       u8 hmc_index;
+       u8 hmc_session;
+       u16 buffer_id = 0;
+       unsigned long flags;
+       int rc = 0;
+
+       if (!crq)
+               return -1;
+
+       hmc_session = crq->hmc_session;
+       hmc_index = crq->hmc_index;
+
+       if (hmc_index > ibmvmc.max_hmc_index) {
+               dev_warn(adapter->dev, "rem_buffer: invalid hmc_index = 0x%x\n",
+                        hmc_index);
+               ibmvmc_send_rem_buffer_resp(adapter, VMC_MSG_INVALID_HMC_INDEX,
+                                           hmc_session, hmc_index, buffer_id);
+               return -1;
+       }
+
+       spin_lock_irqsave(&hmcs[hmc_index].lock, flags);
+       buffer = ibmvmc_get_free_hmc_buffer(adapter, hmc_index);
+       if (!buffer) {
+               dev_info(adapter->dev, "rem_buffer: no buffer to remove\n");
+               spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+               ibmvmc_send_rem_buffer_resp(adapter, VMC_MSG_NO_BUFFER,
+                                           hmc_session, hmc_index,
+                                           VMC_INVALID_BUFFER_ID);
+               return -1;
+       }
+
+       buffer_id = buffer->id;
+
+       if (buffer->valid)
+               free_dma_buffer(to_vio_dev(adapter->dev),
+                               ibmvmc.max_mtu,
+                               buffer->real_addr_local,
+                               buffer->dma_addr_local);
+
+       memset(buffer, 0, sizeof(struct ibmvmc_buffer));
+       spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+
+       dev_dbg(adapter->dev, "rem_buffer: removed buffer 0x%x.\n", buffer_id);
+       ibmvmc_send_rem_buffer_resp(adapter, VMC_MSG_SUCCESS, hmc_session,
+                                   hmc_index, buffer_id);
+
+       return rc;
+}
+
+static int ibmvmc_recv_msg(struct crq_server_adapter *adapter,
+                          struct ibmvmc_crq_msg *crq)
+{
+       struct ibmvmc_buffer *buffer;
+       struct ibmvmc_hmc *hmc;
+       unsigned long msg_len;
+       u8 hmc_index;
+       u8 hmc_session;
+       u16 buffer_id;
+       unsigned long flags;
+       int rc = 0;
+
+       if (!crq)
+               return -1;
+
+       /* Hypervisor writes CRQs directly into our memory in big endian */
+       dev_dbg(adapter->dev, "Recv_msg: msg from HV 0x%016llx 0x%016llx\n",
+               be64_to_cpu(*((unsigned long *)crq)),
+               be64_to_cpu(*(((unsigned long *)crq) + 1)));
+
+       hmc_session = crq->hmc_session;
+       hmc_index = crq->hmc_index;
+       buffer_id = be16_to_cpu(crq->var2.buffer_id);
+       msg_len = be32_to_cpu(crq->var3.msg_len);
+
+       if (hmc_index > ibmvmc.max_hmc_index) {
+               dev_err(adapter->dev, "Recv_msg: invalid hmc_index = 0x%x\n",
+                       hmc_index);
+               ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_HMC_INDEX,
+                                           hmc_session, hmc_index, buffer_id);
+               return -1;
+       }
+
+       if (buffer_id >= ibmvmc.max_buffer_pool_size) {
+               dev_err(adapter->dev, "Recv_msg: invalid buffer_id = 0x%x\n",
+                       buffer_id);
+               ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_BUFFER_ID,
+                                           hmc_session, hmc_index, buffer_id);
+               return -1;
+       }
+
+       hmc = &hmcs[hmc_index];
+       spin_lock_irqsave(&hmc->lock, flags);
+
+       if (hmc->state == ibmhmc_state_free) {
+               dev_err(adapter->dev, "Recv_msg: invalid hmc state = 0x%x\n",
+                       hmc->state);
+               /* HMC connection is not valid (possibly was reset under us). */
+               spin_unlock_irqrestore(&hmc->lock, flags);
+               return -1;
+       }
+
+       buffer = &hmc->buffer[buffer_id];
+
+       if (buffer->valid == 0 || buffer->owner == VMC_BUF_OWNER_ALPHA) {
+               dev_err(adapter->dev, "Recv_msg: not valid, or not HV.  0x%x 
0x%x\n",
+                       buffer->valid, buffer->owner);
+               spin_unlock_irqrestore(&hmc->lock, flags);
+               return -1;
+       }
+
+       /* RDMA the data into the partition. */
+       rc = h_copy_rdma(msg_len,
+                        adapter->riobn,
+                        buffer->dma_addr_remote,
+                        adapter->liobn,
+                        buffer->dma_addr_local);
+
+       dev_dbg(adapter->dev, "Recv_msg: msg_len = 0x%x, buffer_id = 0x%x, 
queue_head = 0x%x, hmc_idx = 0x%x\n",
+               (unsigned int)msg_len, (unsigned int)buffer_id,
+               (unsigned int)hmc->queue_head, (unsigned int)hmc_index);
+       buffer->msg_len = msg_len;
+       buffer->free = 0;
+       buffer->owner = VMC_BUF_OWNER_ALPHA;
+
+       if (rc) {
+               dev_err(adapter->dev, "Failure in recv_msg: h_copy_rdma = 
0x%x\n",
+                       rc);
+               spin_unlock_irqrestore(&hmc->lock, flags);
+               return -1;
+       }
+
+       /* Must be locked because read operates on the same data */
+       hmc->queue_outbound_msgs[hmc->queue_head] = buffer_id;
+       hmc->queue_head++;
+       if (hmc->queue_head == ibmvmc_max_buf_pool_size)
+               hmc->queue_head = 0;
+
+       if (hmc->queue_head == hmc->queue_tail)
+               dev_err(adapter->dev, "outbound buffer queue wrapped.\n");
+
+       spin_unlock_irqrestore(&hmc->lock, flags);
+
+       wake_up_interruptible(&ibmvmc_read_wait);
+
+       return 0;
+}
+
+/**
+ * ibmvmc_process_capabilities - Process Capabilities
+ *
+ * @adapter:   crq_server_adapter struct
+ * @crqp:      ibmvmc_crq_msg struct
+ *
+ */
+static void ibmvmc_process_capabilities(struct crq_server_adapter *adapter,
+                                       struct ibmvmc_crq_msg *crqp)
+{
+       struct ibmvmc_admin_crq_msg *crq = (struct ibmvmc_admin_crq_msg *)crqp;
+
+       if ((be16_to_cpu(crq->version) >> 8) !=
+                       (IBMVMC_PROTOCOL_VERSION >> 8)) {
+               dev_err(adapter->dev, "init failed, incompatible versions 0x%x 
0x%x\n",
+                       be16_to_cpu(crq->version),
+                       IBMVMC_PROTOCOL_VERSION);
+               ibmvmc.state = ibmvmc_state_failed;
+               return;
+       }
+
+       ibmvmc.max_mtu = min_t(u32, ibmvmc_max_mtu, be32_to_cpu(crq->max_mtu));
+       ibmvmc.max_buffer_pool_size = min_t(u16, ibmvmc_max_buf_pool_size,
+                                           be16_to_cpu(crq->pool_size));
+       ibmvmc.max_hmc_index = min_t(u8, ibmvmc_max_hmcs, crq->max_hmc) - 1;
+       ibmvmc.state = ibmvmc_state_ready;
+
+       dev_info(adapter->dev, "Capabilities: mtu=0x%x, pool_size=0x%x, 
max_hmc=0x%x\n",
+                ibmvmc.max_mtu, ibmvmc.max_buffer_pool_size,
+                ibmvmc.max_hmc_index);
+}
+
+/**
+ * ibmvmc_validate_hmc_session - Validate HMC Session
+ *
+ * @adapter:   crq_server_adapter struct
+ * @crq:       ibmvmc_crq_msg struct
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static int ibmvmc_validate_hmc_session(struct crq_server_adapter *adapter,
+                                      struct ibmvmc_crq_msg *crq)
+{
+       unsigned char hmc_index;
+
+       hmc_index = crq->hmc_index;
+
+       if (crq->hmc_session == 0)
+               return 0;
+
+       if (hmc_index > ibmvmc.max_hmc_index)
+               return -1;
+
+       if (hmcs[hmc_index].session != crq->hmc_session) {
+               dev_warn(adapter->dev, "Drop, bad session: expected 0x%x, recv 
0x%x\n",
+                        hmcs[hmc_index].session, crq->hmc_session);
+               return -1;
+       }
+
+       return 0;
+}
+
+/**
+ * ibmvmc_reset - Reset
+ *
+ * @adapter:   crq_server_adapter struct
+ * @xport_event:       export_event field
+ *
+ * Closes all HMC sessions and conditionally schedules a CRQ reset.
+ * @xport_event: If true, the partner closed their CRQ; we don't need to reset.
+ *               If false, we need to schedule a CRQ reset.
+ */
+static void ibmvmc_reset(struct crq_server_adapter *adapter, bool xport_event)
+{
+       int i;
+
+       if (ibmvmc.state != ibmvmc_state_sched_reset) {
+               dev_info(adapter->dev, "*** Reset to initial state.\n");
+               for (i = 0; i < ibmvmc_max_hmcs; i++)
+                       ibmvmc_return_hmc(&hmcs[i], xport_event);
+
+               if (xport_event) {
+                       /* CRQ was closed by the partner.  We don't need to do
+                        * anything except set ourself to the correct state to
+                        * handle init msgs.
+                        */
+                       ibmvmc.state = ibmvmc_state_crqinit;
+               } else {
+                       /* The partner did not close their CRQ - instead, we're
+                        * closing the CRQ on our end. Need to schedule this
+                        * for process context, because CRQ reset may require a
+                        * sleep.
+                        *
+                        * Setting ibmvmc.state here immediately prevents
+                        * ibmvmc_open from completing until the reset
+                        * completes in process context.
+                        */
+                       ibmvmc.state = ibmvmc_state_sched_reset;
+                       dev_dbg(adapter->dev, "Device reset scheduled");
+                       wake_up_interruptible(&adapter->reset_wait_queue);
+               }
+       }
+}
+
+/**
+ * ibmvmc_reset_task - Reset Task
+ *
+ * @data:      Data field
+ *
+ * Performs a CRQ reset of the VMC device in process context.
+ * NOTE: This function should not be called directly, use ibmvmc_reset.
+ */
+static int ibmvmc_reset_task(void *data)
+{
+       struct crq_server_adapter *adapter = data;
+       int rc;
+
+       set_user_nice(current, -20);
+
+       while (!kthread_should_stop()) {
+               wait_event_interruptible(adapter->reset_wait_queue,
+                       (ibmvmc.state == ibmvmc_state_sched_reset) ||
+                       kthread_should_stop());
+
+               if (kthread_should_stop())
+                       break;
+
+               dev_dbg(adapter->dev, "CRQ resetting in process context");
+               tasklet_disable(&adapter->work_task);
+
+               rc = ibmvmc_reset_crq_queue(adapter);
+
+               if (rc != H_SUCCESS && rc != H_RESOURCE) {
+                       dev_err(adapter->dev, "Error initializing CRQ.  rc = 
0x%x\n",
+                               rc);
+                       ibmvmc.state = ibmvmc_state_failed;
+               } else {
+                       ibmvmc.state = ibmvmc_state_crqinit;
+
+                       if (ibmvmc_send_crq(adapter, 0xC001000000000000LL, 0)
+                           != 0 && rc != H_RESOURCE)
+                               dev_warn(adapter->dev, "Failed to send 
initialize CRQ message\n");
+               }
+
+               vio_enable_interrupts(to_vio_dev(adapter->dev));
+               tasklet_enable(&adapter->work_task);
+       }
+
+       return 0;
+}
+
+/**
+ * ibmvmc_process_open_resp - Process Open Response
+ *
+ * @crq: ibmvmc_crq_msg struct
+ * @adapter:    crq_server_adapter struct
+ *
+ * This command is sent by the hypervisor in response to the Interface
+ * Open message. When this message is received, the indicated buffer is
+ * again available for management partition use.
+ */
+static void ibmvmc_process_open_resp(struct ibmvmc_crq_msg *crq,
+                                    struct crq_server_adapter *adapter)
+{
+       unsigned char hmc_index;
+       unsigned short buffer_id;
+
+       hmc_index = crq->hmc_index;
+       if (hmc_index > ibmvmc.max_hmc_index) {
+               /* Why would PHYP give an index > max negotiated? */
+               ibmvmc_reset(adapter, false);
+               return;
+       }
+
+       if (crq->status) {
+               dev_warn(adapter->dev, "open_resp: failed - status 0x%x\n",
+                        crq->status);
+               ibmvmc_return_hmc(&hmcs[hmc_index], false);
+               return;
+       }
+
+       if (hmcs[hmc_index].state == ibmhmc_state_opening) {
+               buffer_id = be16_to_cpu(crq->var2.buffer_id);
+               if (buffer_id >= ibmvmc.max_buffer_pool_size) {
+                       dev_err(adapter->dev, "open_resp: invalid buffer_id = 
0x%x\n",
+                               buffer_id);
+                       hmcs[hmc_index].state = ibmhmc_state_failed;
+               } else {
+                       ibmvmc_free_hmc_buffer(&hmcs[hmc_index],
+                                              
&hmcs[hmc_index].buffer[buffer_id]);
+                       hmcs[hmc_index].state = ibmhmc_state_ready;
+                       dev_dbg(adapter->dev, "open_resp: set hmc state = 
ready\n");
+               }
+       } else {
+               dev_warn(adapter->dev, "open_resp: invalid hmc state (0x%x)\n",
+                        hmcs[hmc_index].state);
+       }
+}
+
+/**
+ * ibmvmc_process_close_resp - Process Close Response
+ *
+ * @crq: ibmvmc_crq_msg struct
+ * @adapter:    crq_server_adapter struct
+ *
+ * This command is sent by the hypervisor in response to the managemant
+ * application Interface Close message.
+ *
+ * If the close fails, simply reset the entire driver as the state of the VMC
+ * must be in tough shape.
+ */
+static void ibmvmc_process_close_resp(struct ibmvmc_crq_msg *crq,
+                                     struct crq_server_adapter *adapter)
+{
+       unsigned char hmc_index;
+
+       hmc_index = crq->hmc_index;
+       if (hmc_index > ibmvmc.max_hmc_index) {
+               ibmvmc_reset(adapter, false);
+               return;
+       }
+
+       if (crq->status) {
+               dev_warn(adapter->dev, "close_resp: failed - status 0x%x\n",
+                        crq->status);
+               ibmvmc_reset(adapter, false);
+               return;
+       }
+
+       ibmvmc_return_hmc(&hmcs[hmc_index], false);
+}
+
+/**
+ * ibmvmc_crq_process - Process CRQ
+ *
+ * @adapter:    crq_server_adapter struct
+ * @crq:       ibmvmc_crq_msg struct
+ *
+ * Process the CRQ message based upon the type of message received.
+ *
+ */
+static void ibmvmc_crq_process(struct crq_server_adapter *adapter,
+                              struct ibmvmc_crq_msg *crq)
+{
+       switch (crq->type) {
+       case VMC_MSG_CAP_RESP:
+               dev_dbg(adapter->dev, "CRQ recv: capabilities resp (0x%x)\n",
+                       crq->type);
+               if (ibmvmc.state == ibmvmc_state_capabilities)
+                       ibmvmc_process_capabilities(adapter, crq);
+               else
+                       dev_warn(adapter->dev, "caps msg invalid in state 
0x%x\n",
+                                ibmvmc.state);
+               break;
+       case VMC_MSG_OPEN_RESP:
+               dev_dbg(adapter->dev, "CRQ recv: open resp (0x%x)\n",
+                       crq->type);
+               if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+                       ibmvmc_process_open_resp(crq, adapter);
+               break;
+       case VMC_MSG_ADD_BUF:
+               dev_dbg(adapter->dev, "CRQ recv: add buf (0x%x)\n",
+                       crq->type);
+               if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+                       ibmvmc_add_buffer(adapter, crq);
+               break;
+       case VMC_MSG_REM_BUF:
+               dev_dbg(adapter->dev, "CRQ recv: rem buf (0x%x)\n",
+                       crq->type);
+               if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+                       ibmvmc_rem_buffer(adapter, crq);
+               break;
+       case VMC_MSG_SIGNAL:
+               dev_dbg(adapter->dev, "CRQ recv: signal msg (0x%x)\n",
+                       crq->type);
+               if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+                       ibmvmc_recv_msg(adapter, crq);
+               break;
+       case VMC_MSG_CLOSE_RESP:
+               dev_dbg(adapter->dev, "CRQ recv: close resp (0x%x)\n",
+                       crq->type);
+               if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+                       ibmvmc_process_close_resp(crq, adapter);
+               break;
+       case VMC_MSG_CAP:
+       case VMC_MSG_OPEN:
+       case VMC_MSG_CLOSE:
+       case VMC_MSG_ADD_BUF_RESP:
+       case VMC_MSG_REM_BUF_RESP:
+               dev_warn(adapter->dev, "CRQ recv: unexpected msg (0x%x)\n",
+                        crq->type);
+               break;
+       default:
+               dev_warn(adapter->dev, "CRQ recv: unknown msg (0x%x)\n",
+                        crq->type);
+               break;
+       }
+}
+
+/**
+ * ibmvmc_handle_crq_init - Handle CRQ Init
+ *
+ * @crq:       ibmvmc_crq_msg struct
+ * @adapter:   crq_server_adapter struct
+ *
+ * Handle the type of crq initialization based on whether
+ * it is a message or a response.
+ *
+ */
+static void ibmvmc_handle_crq_init(struct ibmvmc_crq_msg *crq,
+                                  struct crq_server_adapter *adapter)
+{
+       switch (crq->type) {
+       case 0x01:      /* Initialization message */
+               dev_dbg(adapter->dev, "CRQ recv: CRQ init msg - state 0x%x\n",
+                       ibmvmc.state);
+               if (ibmvmc.state == ibmvmc_state_crqinit) {
+                       /* Send back a response */
+                       if (ibmvmc_send_crq(adapter, 0xC002000000000000,
+                                           0) == 0)
+                               ibmvmc_send_capabilities(adapter);
+                       else
+                               dev_err(adapter->dev, " Unable to send init 
rsp\n");
+               } else {
+                       dev_err(adapter->dev, "Invalid state 0x%x mtu = 0x%x\n",
+                               ibmvmc.state, ibmvmc.max_mtu);
+               }
+
+               break;
+       case 0x02:      /* Initialization response */
+               dev_dbg(adapter->dev, "CRQ recv: initialization resp msg - 
state 0x%x\n",
+                       ibmvmc.state);
+               if (ibmvmc.state == ibmvmc_state_crqinit)
+                       ibmvmc_send_capabilities(adapter);
+               break;
+       default:
+               dev_warn(adapter->dev, "Unknown crq message type 0x%lx\n",
+                        (unsigned long)crq->type);
+       }
+}
+
+/**
+ * ibmvmc_handle_crq - Handle CRQ
+ *
+ * @crq:       ibmvmc_crq_msg struct
+ * @adapter:   crq_server_adapter struct
+ *
+ * Read the command elements from the command queue and execute the
+ * requests based upon the type of crq message.
+ *
+ */
+static void ibmvmc_handle_crq(struct ibmvmc_crq_msg *crq,
+                             struct crq_server_adapter *adapter)
+{
+       switch (crq->valid) {
+       case 0xC0:              /* initialization */
+               ibmvmc_handle_crq_init(crq, adapter);
+               break;
+       case 0xFF:      /* Hypervisor telling us the connection is closed */
+               dev_warn(adapter->dev, "CRQ recv: virtual adapter failed - 
resetting.\n");
+               ibmvmc_reset(adapter, true);
+               break;
+       case 0x80:      /* real payload */
+               ibmvmc_crq_process(adapter, crq);
+               break;
+       default:
+               dev_warn(adapter->dev, "CRQ recv: unknown msg 0x%02x.\n",
+                        crq->valid);
+               break;
+       }
+}
+
+static void ibmvmc_task(unsigned long data)
+{
+       struct crq_server_adapter *adapter =
+               (struct crq_server_adapter *)data;
+       struct vio_dev *vdev = to_vio_dev(adapter->dev);
+       struct ibmvmc_crq_msg *crq;
+       int done = 0;
+
+       while (!done) {
+               /* Pull all the valid messages off the CRQ */
+               while ((crq = crq_queue_next_crq(&adapter->queue)) != NULL) {
+                       ibmvmc_handle_crq(crq, adapter);
+                       crq->valid = 0x00;
+                       /* CRQ reset was requested, stop processing CRQs.
+                        * Interrupts will be re-enabled by the reset task.
+                        */
+                       if (ibmvmc.state == ibmvmc_state_sched_reset)
+                               return;
+               }
+
+               vio_enable_interrupts(vdev);
+               crq = crq_queue_next_crq(&adapter->queue);
+               if (crq) {
+                       vio_disable_interrupts(vdev);
+                       ibmvmc_handle_crq(crq, adapter);
+                       crq->valid = 0x00;
+                       /* CRQ reset was requested, stop processing CRQs.
+                        * Interrupts will be re-enabled by the reset task.
+                        */
+                       if (ibmvmc.state == ibmvmc_state_sched_reset)
+                               return;
+               } else {
+                       done = 1;
+               }
+       }
+}
+
+/**
+ * ibmvmc_init_crq_queue - Init CRQ Queue
+ *
+ * @adapter:   crq_server_adapter struct
+ *
+ * Return:
+ *     0 - Success
+ *     Non-zero - Failure
+ */
+static int ibmvmc_init_crq_queue(struct crq_server_adapter *adapter)
+{
+       struct vio_dev *vdev = to_vio_dev(adapter->dev);
+       struct crq_queue *queue = &adapter->queue;
+       int rc = 0;
+       int retrc = 0;
+
+       queue->msgs = (struct ibmvmc_crq_msg *)get_zeroed_page(GFP_KERNEL);
+
+       if (!queue->msgs)
+               goto malloc_failed;
+
+       queue->size = PAGE_SIZE / sizeof(*queue->msgs);
+
+       queue->msg_token = dma_map_single(adapter->dev, queue->msgs,
+                                         queue->size * sizeof(*queue->msgs),
+                                         DMA_BIDIRECTIONAL);
+
+       if (dma_mapping_error(adapter->dev, queue->msg_token))
+               goto map_failed;
+
+       retrc = plpar_hcall_norets(H_REG_CRQ,
+                                  vdev->unit_address,
+                                  queue->msg_token, PAGE_SIZE);
+       retrc = rc;
+
+       if (rc == H_RESOURCE)
+               rc = ibmvmc_reset_crq_queue(adapter);
+
+       if (rc == 2) {
+               dev_warn(adapter->dev, "Partner adapter not ready\n");
+               retrc = 0;
+       } else if (rc != 0) {
+               dev_err(adapter->dev, "Error %d opening adapter\n", rc);
+               goto reg_crq_failed;
+       }
+
+       queue->cur = 0;
+       spin_lock_init(&queue->lock);
+
+       tasklet_init(&adapter->work_task, ibmvmc_task, (unsigned long)adapter);
+
+       if (request_irq(vdev->irq,
+                       ibmvmc_handle_event,
+                       0, "ibmvmc", (void *)adapter) != 0) {
+               dev_err(adapter->dev, "couldn't register irq 0x%x\n",
+                       vdev->irq);
+               goto req_irq_failed;
+       }
+
+       rc = vio_enable_interrupts(vdev);
+       if (rc != 0) {
+               dev_err(adapter->dev, "Error %d enabling interrupts!!!\n", rc);
+               goto req_irq_failed;
+       }
+
+       return retrc;
+
+req_irq_failed:
+       /* Cannot have any work since we either never got our IRQ registered,
+        * or never got interrupts enabled
+        */
+       tasklet_kill(&adapter->work_task);
+       h_free_crq(vdev->unit_address);
+reg_crq_failed:
+       dma_unmap_single(adapter->dev,
+                        queue->msg_token,
+                        queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
+map_failed:
+       free_page((unsigned long)queue->msgs);
+malloc_failed:
+       return -ENOMEM;
+}
+
+/* Fill in the liobn and riobn fields on the adapter */
+static int read_dma_window(struct vio_dev *vdev,
+                          struct crq_server_adapter *adapter)
+{
+       const __be32 *dma_window;
+       const __be32 *prop;
+
+       /* TODO Using of_parse_dma_window would be better, but it doesn't give
+        * a way to read multiple windows without already knowing the size of
+        * a window or the number of windows
+        */
+       dma_window =
+               (const __be32 *)vio_get_attribute(vdev, "ibm,my-dma-window",
+                                               NULL);
+       if (!dma_window) {
+               dev_warn(adapter->dev, "Couldn't find ibm,my-dma-window 
property\n");
+               return -1;
+       }
+
+       adapter->liobn = be32_to_cpu(*dma_window);
+       dma_window++;
+
+       prop = (const __be32 *)vio_get_attribute(vdev, "ibm,#dma-address-cells",
+                                               NULL);
+       if (!prop) {
+               dev_warn(adapter->dev, "Couldn't find ibm,#dma-address-cells 
property\n");
+               dma_window++;
+       } else {
+               dma_window += be32_to_cpu(*prop);
+       }
+
+       prop = (const __be32 *)vio_get_attribute(vdev, "ibm,#dma-size-cells",
+                                               NULL);
+       if (!prop) {
+               dev_warn(adapter->dev, "Couldn't find ibm,#dma-size-cells 
property\n");
+               dma_window++;
+       } else {
+               dma_window += be32_to_cpu(*prop);
+       }
+
+       /* dma_window should point to the second window now */
+       adapter->riobn = be32_to_cpu(*dma_window);
+
+       return 0;
+}
+
+static int ibmvmc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
+{
+       struct crq_server_adapter *adapter = &ibmvmc_adapter;
+       int rc;
+
+       dev_set_drvdata(&vdev->dev, NULL);
+       memset(adapter, 0, sizeof(*adapter));
+       adapter->dev = &vdev->dev;
+
+       dev_info(adapter->dev, "Probe for UA 0x%x\n", vdev->unit_address);
+
+       rc = read_dma_window(vdev, adapter);
+       if (rc != 0) {
+               ibmvmc.state = ibmvmc_state_failed;
+               return -1;
+       }
+
+       dev_dbg(adapter->dev, "Probe: liobn 0x%x, riobn 0x%x\n",
+               adapter->liobn, adapter->riobn);
+
+       init_waitqueue_head(&adapter->reset_wait_queue);
+       adapter->reset_task = kthread_run(ibmvmc_reset_task, adapter, "ibmvmc");
+       if (IS_ERR(adapter->reset_task)) {
+               dev_err(adapter->dev, "Failed to start reset thread\n");
+               ibmvmc.state = ibmvmc_state_failed;
+               rc = PTR_ERR(adapter->reset_task);
+               adapter->reset_task = NULL;
+               return rc;
+       }
+
+       rc = ibmvmc_init_crq_queue(adapter);
+       if (rc != 0 && rc != H_RESOURCE) {
+               dev_err(adapter->dev, "Error initializing CRQ.  rc = 0x%x\n",
+                       rc);
+               ibmvmc.state = ibmvmc_state_failed;
+               goto crq_failed;
+       }
+
+       ibmvmc.state = ibmvmc_state_crqinit;
+
+       /* Try to send an initialization message.  Note that this is allowed
+        * to fail if the other end is not acive.  In that case we just wait
+        * for the other side to initialize.
+        */
+       if (ibmvmc_send_crq(adapter, 0xC001000000000000LL, 0) != 0 &&
+           rc != H_RESOURCE)
+               dev_warn(adapter->dev, "Failed to send initialize CRQ 
message\n");
+
+       dev_set_drvdata(&vdev->dev, adapter);
+
+       return 0;
+
+crq_failed:
+       kthread_stop(adapter->reset_task);
+       adapter->reset_task = NULL;
+       return -EPERM;
+}
+
+static int ibmvmc_remove(struct vio_dev *vdev)
+{
+       struct crq_server_adapter *adapter = dev_get_drvdata(&vdev->dev);
+
+       dev_info(adapter->dev, "Entering remove for UA 0x%x\n",
+                vdev->unit_address);
+       ibmvmc_release_crq_queue(adapter);
+
+       return 0;
+}
+
+static struct vio_device_id ibmvmc_device_table[] = {
+       { "ibm,vmc", "IBM,vmc" },
+       { "", "" }
+};
+MODULE_DEVICE_TABLE(vio, ibmvmc_device_table);
+
+static struct vio_driver ibmvmc_driver = {
+       .name        = ibmvmc_driver_name,
+       .id_table    = ibmvmc_device_table,
+       .probe       = ibmvmc_probe,
+       .remove      = ibmvmc_remove,
+};
+
+static void __init ibmvmc_scrub_module_parms(void)
+{
+       if (ibmvmc_max_mtu > MAX_MTU) {
+               pr_warn("ibmvmc: Max MTU reduced to %d\n", MAX_MTU);
+               ibmvmc_max_mtu = MAX_MTU;
+       } else if (ibmvmc_max_mtu < MIN_MTU) {
+               pr_warn("ibmvmc: Max MTU increased to %d\n", MIN_MTU);
+               ibmvmc_max_mtu = MIN_MTU;
+       }
+
+       if (ibmvmc_max_buf_pool_size > MAX_BUF_POOL_SIZE) {
+               pr_warn("ibmvmc: Max buffer pool size reduced to %d\n",
+                       MAX_BUF_POOL_SIZE);
+               ibmvmc_max_buf_pool_size = MAX_BUF_POOL_SIZE;
+       } else if (ibmvmc_max_buf_pool_size < MIN_BUF_POOL_SIZE) {
+               pr_warn("ibmvmc: Max buffer pool size increased to %d\n",
+                       MIN_BUF_POOL_SIZE);
+               ibmvmc_max_buf_pool_size = MIN_BUF_POOL_SIZE;
+       }
+
+       if (ibmvmc_max_hmcs > MAX_HMCS) {
+               pr_warn("ibmvmc: Max HMCs reduced to %d\n", MAX_HMCS);
+               ibmvmc_max_hmcs = MAX_HMCS;
+       } else if (ibmvmc_max_hmcs < MIN_HMCS) {
+               pr_warn("ibmvmc: Max HMCs increased to %d\n", MIN_HMCS);
+               ibmvmc_max_hmcs = MIN_HMCS;
+       }
+}
+
+static struct miscdevice ibmvmc_miscdev = {
+       .name = ibmvmc_driver_name,
+       .minor = MISC_DYNAMIC_MINOR,
+       .fops = &ibmvmc_fops,
+};
+
+static int __init ibmvmc_module_init(void)
+{
+       int rc, i, j;
+
+       ibmvmc.state = ibmvmc_state_initial;
+       pr_info("ibmvmc: version %s\n", IBMVMC_DRIVER_VERSION);
+
+       rc = misc_register(&ibmvmc_miscdev);
+       if (rc) {
+               pr_err("ibmvmc: misc registration failed\n");
+               goto misc_register_failed;
+       }
+       pr_info("ibmvmc: node %d:%d\n", MISC_MAJOR,
+               ibmvmc_miscdev.minor);
+
+       /* Initialize data structures */
+       memset(hmcs, 0, sizeof(struct ibmvmc_hmc) * MAX_HMCS);
+       for (i = 0; i < MAX_HMCS; i++) {
+               spin_lock_init(&hmcs[i].lock);
+               hmcs[i].state = ibmhmc_state_free;
+               for (j = 0; j < MAX_BUF_POOL_SIZE; j++)
+                       hmcs[i].queue_outbound_msgs[j] = VMC_INVALID_BUFFER_ID;
+       }
+
+       /* Sanity check module parms */
+       ibmvmc_scrub_module_parms();
+
+       /*
+        * Initialize some reasonable values.  Might be negotiated smaller
+        * values during the capabilities exchange.
+        */
+       ibmvmc.max_mtu = ibmvmc_max_mtu;
+       ibmvmc.max_buffer_pool_size = ibmvmc_max_buf_pool_size;
+       ibmvmc.max_hmc_index = ibmvmc_max_hmcs - 1;
+
+       rc = vio_register_driver(&ibmvmc_driver);
+
+       if (rc) {
+               pr_err("ibmvmc: rc %d from vio_register_driver\n", rc);
+               goto vio_reg_failed;
+       }
+
+       return 0;
+
+vio_reg_failed:
+       misc_deregister(&ibmvmc_miscdev);
+misc_register_failed:
+       return rc;
+}
+
+static void __exit ibmvmc_module_exit(void)
+{
+       pr_info("ibmvmc: module exit\n");
+       vio_unregister_driver(&ibmvmc_driver);
+       misc_deregister(&ibmvmc_miscdev);
+}
+
+module_init(ibmvmc_module_init);
+module_exit(ibmvmc_module_exit);
+
+module_param_named(buf_pool_size, ibmvmc_max_buf_pool_size,
+                  int, 0644);
+MODULE_PARM_DESC(buf_pool_size, "Buffer pool size");
+module_param_named(max_hmcs, ibmvmc_max_hmcs, int, 0644);
+MODULE_PARM_DESC(max_hmcs, "Max HMCs");
+module_param_named(max_mtu, ibmvmc_max_mtu, int, 0644);
+MODULE_PARM_DESC(max_mtu, "Max MTU");
+
+MODULE_AUTHOR("Steven Royer <sero...@linux.vnet.ibm.com>");
+MODULE_DESCRIPTION("IBM VMC");
+MODULE_VERSION(IBMVMC_DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/misc/ibmvmc.h b/drivers/misc/ibmvmc.h
new file mode 100644
index 0000000..e140ada
--- /dev/null
+++ b/drivers/misc/ibmvmc.h
@@ -0,0 +1,209 @@
+/* SPDX-License-Identifier: GPL-2.0+
+ *
+ * linux/drivers/misc/ibmvmc.h
+ *
+ * IBM Power Systems Virtual Management Channel Support.
+ *
+ * Copyright (c) 2004, 2018 IBM Corp.
+ *   Dave Engebretsen engeb...@us.ibm.com
+ *   Steven Royer sero...@linux.vnet.ibm.com
+ *   Adam Reznechek adrez...@linux.vnet.ibm.com
+ *   Bryant G. Ly <bryan...@linux.vnet.ibm.com>
+ */
+#ifndef IBMVMC_H
+#define IBMVMC_H
+
+#include <linux/types.h>
+#include <linux/cdev.h>
+
+#include <asm/vio.h>
+
+#define IBMVMC_PROTOCOL_VERSION    0x0101
+
+#define MIN_BUF_POOL_SIZE 16
+#define MIN_HMCS          1
+#define MIN_MTU           4096
+#define MAX_BUF_POOL_SIZE 64
+#define MAX_HMCS          2
+#define MAX_MTU           (4 * 4096)
+#define DEFAULT_BUF_POOL_SIZE 32
+#define DEFAULT_HMCS          1
+#define DEFAULT_MTU           4096
+#define HMC_ID_LEN        32
+
+#define VMC_INVALID_BUFFER_ID 0xFFFF
+
+/* ioctl numbers */
+#define VMC_BASE            0xCC
+#define VMC_IOCTL_SETHMCID   _IOW(VMC_BASE, 0x00, unsigned char *)
+#define VMC_IOCTL_QUERY      _IOR(VMC_BASE, 0x01, struct ibmvmc_query_struct)
+#define VMC_IOCTL_REQUESTVMC _IOR(VMC_BASE, 0x02, u32)
+
+#define VMC_MSG_CAP          0x01
+#define VMC_MSG_CAP_RESP     0x81
+#define VMC_MSG_OPEN         0x02
+#define VMC_MSG_OPEN_RESP    0x82
+#define VMC_MSG_CLOSE        0x03
+#define VMC_MSG_CLOSE_RESP   0x83
+#define VMC_MSG_ADD_BUF      0x04
+#define VMC_MSG_ADD_BUF_RESP 0x84
+#define VMC_MSG_REM_BUF      0x05
+#define VMC_MSG_REM_BUF_RESP 0x85
+#define VMC_MSG_SIGNAL       0x06
+
+#define VMC_MSG_SUCCESS 0
+#define VMC_MSG_INVALID_HMC_INDEX 1
+#define VMC_MSG_INVALID_BUFFER_ID 2
+#define VMC_MSG_CLOSED_HMC        3
+#define VMC_MSG_INTERFACE_FAILURE 4
+#define VMC_MSG_NO_BUFFER         5
+
+#define VMC_BUF_OWNER_ALPHA 0
+#define VMC_BUF_OWNER_HV    1
+
+enum ibmvmc_states {
+       ibmvmc_state_sched_reset  = -1,
+       ibmvmc_state_initial      = 0,
+       ibmvmc_state_crqinit      = 1,
+       ibmvmc_state_capabilities = 2,
+       ibmvmc_state_ready        = 3,
+       ibmvmc_state_failed       = 4,
+};
+
+enum ibmhmc_states {
+       /* HMC connection not established */
+       ibmhmc_state_free    = 0,
+
+       /* HMC connection established (open called) */
+       ibmhmc_state_initial = 1,
+
+       /* open msg sent to HV, due to ioctl(1) call */
+       ibmhmc_state_opening = 2,
+
+       /* HMC connection ready, open resp msg from HV */
+       ibmhmc_state_ready   = 3,
+
+       /* HMC connection failure */
+       ibmhmc_state_failed  = 4,
+};
+
+struct ibmvmc_buffer {
+       u8 valid;       /* 1 when DMA storage allocated to buffer          */
+       u8 free;        /* 1 when buffer available for the Alpha Partition */
+       u8 owner;
+       u16 id;
+       u32 size;
+       u32 msg_len;
+       dma_addr_t dma_addr_local;
+       dma_addr_t dma_addr_remote;
+       void *real_addr_local;
+};
+
+struct ibmvmc_admin_crq_msg {
+       u8 valid;       /* RPA Defined           */
+       u8 type;        /* ibmvmc msg type       */
+       u8 status;      /* Response msg status. Zero is success and on failure,
+                        * either 1 - General Failure, or 2 - Invalid Version is
+                        * returned.
+                        */
+       u8 rsvd[2];
+       u8 max_hmc;     /* Max # of independent HMC connections supported */
+       __be16 pool_size;       /* Maximum number of buffers supported per HMC
+                                * connection
+                                */
+       __be32 max_mtu;         /* Maximum message size supported (bytes) */
+       __be16 crq_size;        /* # of entries available in the CRQ for the
+                                * source partition. The target partition must
+                                * limit the number of outstanding messages to
+                                * one half or less.
+                                */
+       __be16 version; /* Indicates the code level of the management partition
+                        * or the hypervisor with the high-order byte
+                        * indicating a major version and the low-order byte
+                        * indicating a minor version.
+                        */
+};
+
+struct ibmvmc_crq_msg {
+       u8 valid;     /* RPA Defined           */
+       u8 type;      /* ibmvmc msg type       */
+       u8 status;    /* Response msg status   */
+       union {
+               u8 rsvd;  /* Reserved              */
+               u8 owner;
+       } var1;
+       u8 hmc_session; /* Session Identifier for the current VMC connection */
+       u8 hmc_index;   /* A unique HMC Idx would be used if multiple management
+                        * applications running concurrently were desired
+                        */
+       union {
+               __be16 rsvd;
+               __be16 buffer_id;
+       } var2;
+       __be32 rsvd;
+       union {
+               __be32 rsvd;
+               __be32 lioba;
+               __be32 msg_len;
+       } var3;
+};
+
+/* an RPA command/response transport queue */
+struct crq_queue {
+       struct ibmvmc_crq_msg *msgs;
+       int size, cur;
+       dma_addr_t msg_token;
+       spinlock_t lock;
+};
+
+/* VMC server adapter settings */
+struct crq_server_adapter {
+       struct device *dev;
+       struct crq_queue queue;
+       u32 liobn;
+       u32 riobn;
+       struct tasklet_struct work_task;
+       wait_queue_head_t reset_wait_queue;
+       struct task_struct *reset_task;
+};
+
+/* Driver wide settings */
+struct ibmvmc_struct {
+       u32 state;
+       u32 max_mtu;
+       u32 max_buffer_pool_size;
+       u32 max_hmc_index;
+       struct crq_server_adapter *adapter;
+       struct cdev cdev;
+       u32 vmc_drc_index;
+};
+
+struct ibmvmc_file_session;
+
+/* Connection specific settings */
+struct ibmvmc_hmc {
+       u8 session;
+       u8 index;
+       u32 state;
+       struct crq_server_adapter *adapter;
+       spinlock_t lock;
+       unsigned char hmc_id[HMC_ID_LEN];
+       struct ibmvmc_buffer buffer[MAX_BUF_POOL_SIZE];
+       unsigned short queue_outbound_msgs[MAX_BUF_POOL_SIZE];
+       int queue_head, queue_tail;
+       struct ibmvmc_file_session *file_session;
+};
+
+struct ibmvmc_file_session {
+       struct file *file;
+       struct ibmvmc_hmc *hmc;
+       bool valid;
+};
+
+struct ibmvmc_query_struct {
+       int have_vmc;
+       int state;
+       int vmc_drc_index;
+};
+
+#endif /* __IBMVMC_H */
-- 
2.7.2

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