Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / scsi / ibmvscsi / ibmvscsi.c
diff --git a/kernel/drivers/scsi/ibmvscsi/ibmvscsi.c b/kernel/drivers/scsi/ibmvscsi/ibmvscsi.c
new file mode 100644 (file)
index 0000000..acea5d6
--- /dev/null
@@ -0,0 +1,2438 @@
+/* ------------------------------------------------------------
+ * ibmvscsi.c
+ * (C) Copyright IBM Corporation 1994, 2004
+ * Authors: Colin DeVilbiss (devilbis@us.ibm.com)
+ *          Santiago Leon (santil@us.ibm.com)
+ *          Dave Boutcher (sleddog@us.ibm.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
+ * USA
+ *
+ * ------------------------------------------------------------
+ * Emulation of a SCSI host adapter for Virtual I/O devices
+ *
+ * This driver supports the SCSI adapter implemented by the IBM
+ * Power5 firmware.  That SCSI adapter is not a physical adapter,
+ * but allows Linux SCSI peripheral drivers to directly
+ * access devices in another logical partition on the physical system.
+ *
+ * The virtual adapter(s) are present in the open firmware device
+ * tree just like real adapters.
+ *
+ * One of the capabilities provided on these systems is the ability
+ * to DMA between partitions.  The architecture states that for VSCSI,
+ * the server side is allowed to DMA to and from the client.  The client
+ * is never trusted to DMA to or from the server directly.
+ *
+ * Messages are sent between partitions on a "Command/Response Queue" 
+ * (CRQ), which is just a buffer of 16 byte entries in the receiver's 
+ * Senders cannot access the buffer directly, but send messages by
+ * making a hypervisor call and passing in the 16 bytes.  The hypervisor
+ * puts the message in the next 16 byte space in round-robin fashion,
+ * turns on the high order bit of the message (the valid bit), and 
+ * generates an interrupt to the receiver (if interrupts are turned on.) 
+ * The receiver just turns off the valid bit when they have copied out
+ * the message.
+ *
+ * The VSCSI client builds a SCSI Remote Protocol (SRP) Information Unit
+ * (IU) (as defined in the T10 standard available at www.t10.org), gets 
+ * a DMA address for the message, and sends it to the server as the
+ * payload of a CRQ message.  The server DMAs the SRP IU and processes it,
+ * including doing any additional data transfers.  When it is done, it
+ * DMAs the SRP response back to the same address as the request came from,
+ * and sends a CRQ message back to inform the client that the request has
+ * completed.
+ *
+ * TODO: This is currently pretty tied to the IBM pSeries hypervisor
+ * interfaces.  It would be really nice to abstract this above an RDMA
+ * layer.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/dma-mapping.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/kthread.h>
+#include <asm/firmware.h>
+#include <asm/vio.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_transport_srp.h>
+#include "ibmvscsi.h"
+
+/* The values below are somewhat arbitrary default values, but 
+ * OS/400 will use 3 busses (disks, CDs, tapes, I think.)
+ * Note that there are 3 bits of channel value, 6 bits of id, and
+ * 5 bits of LUN.
+ */
+static int max_id = 64;
+static int max_channel = 3;
+static int init_timeout = 300;
+static int login_timeout = 60;
+static int info_timeout = 30;
+static int abort_timeout = 60;
+static int reset_timeout = 60;
+static int max_requests = IBMVSCSI_MAX_REQUESTS_DEFAULT;
+static int max_events = IBMVSCSI_MAX_REQUESTS_DEFAULT + 2;
+static int fast_fail = 1;
+static int client_reserve = 1;
+static char partition_name[97] = "UNKNOWN";
+static unsigned int partition_number = -1;
+
+static struct scsi_transport_template *ibmvscsi_transport_template;
+
+#define IBMVSCSI_VERSION "1.5.9"
+
+MODULE_DESCRIPTION("IBM Virtual SCSI");
+MODULE_AUTHOR("Dave Boutcher");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(IBMVSCSI_VERSION);
+
+module_param_named(max_id, max_id, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(max_id, "Largest ID value for each channel");
+module_param_named(max_channel, max_channel, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(max_channel, "Largest channel value");
+module_param_named(init_timeout, init_timeout, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(init_timeout, "Initialization timeout in seconds");
+module_param_named(max_requests, max_requests, int, S_IRUGO);
+MODULE_PARM_DESC(max_requests, "Maximum requests for this adapter");
+module_param_named(fast_fail, fast_fail, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(fast_fail, "Enable fast fail. [Default=1]");
+module_param_named(client_reserve, client_reserve, int, S_IRUGO );
+MODULE_PARM_DESC(client_reserve, "Attempt client managed reserve/release");
+
+static void ibmvscsi_handle_crq(struct viosrp_crq *crq,
+                               struct ibmvscsi_host_data *hostdata);
+
+/* ------------------------------------------------------------
+ * Routines for managing the command/response queue
+ */
+/**
+ * ibmvscsi_handle_event: - Interrupt handler for crq events
+ * @irq:       number of irq to handle, not used
+ * @dev_instance: ibmvscsi_host_data of host that received interrupt
+ *
+ * Disables interrupts and schedules srp_task
+ * Always returns IRQ_HANDLED
+ */
+static irqreturn_t ibmvscsi_handle_event(int irq, void *dev_instance)
+{
+       struct ibmvscsi_host_data *hostdata =
+           (struct ibmvscsi_host_data *)dev_instance;
+       vio_disable_interrupts(to_vio_dev(hostdata->dev));
+       tasklet_schedule(&hostdata->srp_task);
+       return IRQ_HANDLED;
+}
+
+/**
+ * release_crq_queue: - Deallocates data and unregisters CRQ
+ * @queue:     crq_queue to initialize and register
+ * @host_data: ibmvscsi_host_data of host
+ *
+ * Frees irq, deallocates a page for messages, unmaps dma, and unregisters
+ * the crq with the hypervisor.
+ */
+static void ibmvscsi_release_crq_queue(struct crq_queue *queue,
+                                      struct ibmvscsi_host_data *hostdata,
+                                      int max_requests)
+{
+       long rc = 0;
+       struct vio_dev *vdev = to_vio_dev(hostdata->dev);
+       free_irq(vdev->irq, (void *)hostdata);
+       tasklet_kill(&hostdata->srp_task);
+       do {
+               if (rc)
+                       msleep(100);
+               rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
+       } while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
+       dma_unmap_single(hostdata->dev,
+                        queue->msg_token,
+                        queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
+       free_page((unsigned long)queue->msgs);
+}
+
+/**
+ * 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 viosrp_crq *crq_queue_next_crq(struct crq_queue *queue)
+{
+       struct viosrp_crq *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
+                */
+               rmb();
+       } else
+               crq = NULL;
+       spin_unlock_irqrestore(&queue->lock, flags);
+
+       return crq;
+}
+
+/**
+ * ibmvscsi_send_crq: - Send a CRQ
+ * @hostdata:  the adapter
+ * @word1:     the first 64 bits of the data
+ * @word2:     the second 64 bits of the data
+ */
+static int ibmvscsi_send_crq(struct ibmvscsi_host_data *hostdata,
+                            u64 word1, u64 word2)
+{
+       struct vio_dev *vdev = to_vio_dev(hostdata->dev);
+
+       /*
+        * Ensure the command buffer is flushed to memory before handing it
+        * over to the VIOS to prevent it from fetching any stale data.
+        */
+       mb();
+       return plpar_hcall_norets(H_SEND_CRQ, vdev->unit_address, word1, word2);
+}
+
+/**
+ * ibmvscsi_task: - Process srps asynchronously
+ * @data:      ibmvscsi_host_data of host
+ */
+static void ibmvscsi_task(void *data)
+{
+       struct ibmvscsi_host_data *hostdata = (struct ibmvscsi_host_data *)data;
+       struct vio_dev *vdev = to_vio_dev(hostdata->dev);
+       struct viosrp_crq *crq;
+       int done = 0;
+
+       while (!done) {
+               /* Pull all the valid messages off the CRQ */
+               while ((crq = crq_queue_next_crq(&hostdata->queue)) != NULL) {
+                       ibmvscsi_handle_crq(crq, hostdata);
+                       crq->valid = 0x00;
+               }
+
+               vio_enable_interrupts(vdev);
+               crq = crq_queue_next_crq(&hostdata->queue);
+               if (crq != NULL) {
+                       vio_disable_interrupts(vdev);
+                       ibmvscsi_handle_crq(crq, hostdata);
+                       crq->valid = 0x00;
+               } else {
+                       done = 1;
+               }
+       }
+}
+
+static void gather_partition_info(void)
+{
+       struct device_node *rootdn;
+
+       const char *ppartition_name;
+       const __be32 *p_number_ptr;
+
+       /* Retrieve information about this partition */
+       rootdn = of_find_node_by_path("/");
+       if (!rootdn) {
+               return;
+       }
+
+       ppartition_name = of_get_property(rootdn, "ibm,partition-name", NULL);
+       if (ppartition_name)
+               strncpy(partition_name, ppartition_name,
+                               sizeof(partition_name));
+       p_number_ptr = of_get_property(rootdn, "ibm,partition-no", NULL);
+       if (p_number_ptr)
+               partition_number = of_read_number(p_number_ptr, 1);
+       of_node_put(rootdn);
+}
+
+static void set_adapter_info(struct ibmvscsi_host_data *hostdata)
+{
+       memset(&hostdata->madapter_info, 0x00,
+                       sizeof(hostdata->madapter_info));
+
+       dev_info(hostdata->dev, "SRP_VERSION: %s\n", SRP_VERSION);
+       strcpy(hostdata->madapter_info.srp_version, SRP_VERSION);
+
+       strncpy(hostdata->madapter_info.partition_name, partition_name,
+                       sizeof(hostdata->madapter_info.partition_name));
+
+       hostdata->madapter_info.partition_number =
+                                       cpu_to_be32(partition_number);
+
+       hostdata->madapter_info.mad_version = cpu_to_be32(1);
+       hostdata->madapter_info.os_type = cpu_to_be32(2);
+}
+
+/**
+ * reset_crq_queue: - resets a crq after a failure
+ * @queue:     crq_queue to initialize and register
+ * @hostdata:  ibmvscsi_host_data of host
+ *
+ */
+static int ibmvscsi_reset_crq_queue(struct crq_queue *queue,
+                                   struct ibmvscsi_host_data *hostdata)
+{
+       int rc = 0;
+       struct vio_dev *vdev = to_vio_dev(hostdata->dev);
+
+       /* Close the CRQ */
+       do {
+               if (rc)
+                       msleep(100);
+               rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
+       } while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
+
+       /* Clean out the queue */
+       memset(queue->msgs, 0x00, PAGE_SIZE);
+       queue->cur = 0;
+
+       set_adapter_info(hostdata);
+
+       /* 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(hostdata->dev, "Partner adapter not ready\n");
+       } else if (rc != 0) {
+               dev_warn(hostdata->dev, "couldn't register crq--rc 0x%x\n", rc);
+       }
+       return rc;
+}
+
+/**
+ * initialize_crq_queue: - Initializes and registers CRQ with hypervisor
+ * @queue:     crq_queue to initialize and register
+ * @hostdata:  ibmvscsi_host_data of host
+ *
+ * Allocates a page for messages, maps it for dma, and registers
+ * the crq with the hypervisor.
+ * Returns zero on success.
+ */
+static int ibmvscsi_init_crq_queue(struct crq_queue *queue,
+                                  struct ibmvscsi_host_data *hostdata,
+                                  int max_requests)
+{
+       int rc;
+       int retrc;
+       struct vio_dev *vdev = to_vio_dev(hostdata->dev);
+
+       queue->msgs = (struct viosrp_crq *)get_zeroed_page(GFP_KERNEL);
+
+       if (!queue->msgs)
+               goto malloc_failed;
+       queue->size = PAGE_SIZE / sizeof(*queue->msgs);
+
+       queue->msg_token = dma_map_single(hostdata->dev, queue->msgs,
+                                         queue->size * sizeof(*queue->msgs),
+                                         DMA_BIDIRECTIONAL);
+
+       if (dma_mapping_error(hostdata->dev, queue->msg_token))
+               goto map_failed;
+
+       gather_partition_info();
+       set_adapter_info(hostdata);
+
+       retrc = rc = plpar_hcall_norets(H_REG_CRQ,
+                               vdev->unit_address,
+                               queue->msg_token, PAGE_SIZE);
+       if (rc == H_RESOURCE)
+               /* maybe kexecing and resource is busy. try a reset */
+               rc = ibmvscsi_reset_crq_queue(queue,
+                                             hostdata);
+
+       if (rc == 2) {
+               /* Adapter is good, but other end is not ready */
+               dev_warn(hostdata->dev, "Partner adapter not ready\n");
+               retrc = 0;
+       } else if (rc != 0) {
+               dev_warn(hostdata->dev, "Error %d opening adapter\n", rc);
+               goto reg_crq_failed;
+       }
+
+       queue->cur = 0;
+       spin_lock_init(&queue->lock);
+
+       tasklet_init(&hostdata->srp_task, (void *)ibmvscsi_task,
+                    (unsigned long)hostdata);
+
+       if (request_irq(vdev->irq,
+                       ibmvscsi_handle_event,
+                       0, "ibmvscsi", (void *)hostdata) != 0) {
+               dev_err(hostdata->dev, "couldn't register irq 0x%x\n",
+                       vdev->irq);
+               goto req_irq_failed;
+       }
+
+       rc = vio_enable_interrupts(vdev);
+       if (rc != 0) {
+               dev_err(hostdata->dev, "Error %d enabling interrupts!!!\n", rc);
+               goto req_irq_failed;
+       }
+
+       return retrc;
+
+      req_irq_failed:
+       tasklet_kill(&hostdata->srp_task);
+       rc = 0;
+       do {
+               if (rc)
+                       msleep(100);
+               rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
+       } while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
+      reg_crq_failed:
+       dma_unmap_single(hostdata->dev,
+                        queue->msg_token,
+                        queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
+      map_failed:
+       free_page((unsigned long)queue->msgs);
+      malloc_failed:
+       return -1;
+}
+
+/**
+ * reenable_crq_queue: - reenables a crq after
+ * @queue:     crq_queue to initialize and register
+ * @hostdata:  ibmvscsi_host_data of host
+ *
+ */
+static int ibmvscsi_reenable_crq_queue(struct crq_queue *queue,
+                                      struct ibmvscsi_host_data *hostdata)
+{
+       int rc = 0;
+       struct vio_dev *vdev = to_vio_dev(hostdata->dev);
+
+       /* Re-enable the CRQ */
+       do {
+               if (rc)
+                       msleep(100);
+               rc = plpar_hcall_norets(H_ENABLE_CRQ, vdev->unit_address);
+       } while ((rc == H_IN_PROGRESS) || (rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
+
+       if (rc)
+               dev_err(hostdata->dev, "Error %d enabling adapter\n", rc);
+       return rc;
+}
+
+/* ------------------------------------------------------------
+ * Routines for the event pool and event structs
+ */
+/**
+ * initialize_event_pool: - Allocates and initializes the event pool for a host
+ * @pool:      event_pool to be initialized
+ * @size:      Number of events in pool
+ * @hostdata:  ibmvscsi_host_data who owns the event pool
+ *
+ * Returns zero on success.
+*/
+static int initialize_event_pool(struct event_pool *pool,
+                                int size, struct ibmvscsi_host_data *hostdata)
+{
+       int i;
+
+       pool->size = size;
+       pool->next = 0;
+       pool->events = kcalloc(pool->size, sizeof(*pool->events), GFP_KERNEL);
+       if (!pool->events)
+               return -ENOMEM;
+
+       pool->iu_storage =
+           dma_alloc_coherent(hostdata->dev,
+                              pool->size * sizeof(*pool->iu_storage),
+                              &pool->iu_token, 0);
+       if (!pool->iu_storage) {
+               kfree(pool->events);
+               return -ENOMEM;
+       }
+
+       for (i = 0; i < pool->size; ++i) {
+               struct srp_event_struct *evt = &pool->events[i];
+               memset(&evt->crq, 0x00, sizeof(evt->crq));
+               atomic_set(&evt->free, 1);
+               evt->crq.valid = 0x80;
+               evt->crq.IU_length = cpu_to_be16(sizeof(*evt->xfer_iu));
+               evt->crq.IU_data_ptr = cpu_to_be64(pool->iu_token +
+                       sizeof(*evt->xfer_iu) * i);
+               evt->xfer_iu = pool->iu_storage + i;
+               evt->hostdata = hostdata;
+               evt->ext_list = NULL;
+               evt->ext_list_token = 0;
+       }
+
+       return 0;
+}
+
+/**
+ * release_event_pool: - Frees memory of an event pool of a host
+ * @pool:      event_pool to be released
+ * @hostdata:  ibmvscsi_host_data who owns the even pool
+ *
+ * Returns zero on success.
+*/
+static void release_event_pool(struct event_pool *pool,
+                              struct ibmvscsi_host_data *hostdata)
+{
+       int i, in_use = 0;
+       for (i = 0; i < pool->size; ++i) {
+               if (atomic_read(&pool->events[i].free) != 1)
+                       ++in_use;
+               if (pool->events[i].ext_list) {
+                       dma_free_coherent(hostdata->dev,
+                                 SG_ALL * sizeof(struct srp_direct_buf),
+                                 pool->events[i].ext_list,
+                                 pool->events[i].ext_list_token);
+               }
+       }
+       if (in_use)
+               dev_warn(hostdata->dev, "releasing event pool with %d "
+                        "events still in use?\n", in_use);
+       kfree(pool->events);
+       dma_free_coherent(hostdata->dev,
+                         pool->size * sizeof(*pool->iu_storage),
+                         pool->iu_storage, pool->iu_token);
+}
+
+/**
+ * valid_event_struct: - Determines if event is valid.
+ * @pool:      event_pool that contains the event
+ * @evt:       srp_event_struct to be checked for validity
+ *
+ * Returns zero if event is invalid, one otherwise.
+*/
+static int valid_event_struct(struct event_pool *pool,
+                               struct srp_event_struct *evt)
+{
+       int index = evt - pool->events;
+       if (index < 0 || index >= pool->size)   /* outside of bounds */
+               return 0;
+       if (evt != pool->events + index)        /* unaligned */
+               return 0;
+       return 1;
+}
+
+/**
+ * ibmvscsi_free-event_struct: - Changes status of event to "free"
+ * @pool:      event_pool that contains the event
+ * @evt:       srp_event_struct to be modified
+ *
+*/
+static void free_event_struct(struct event_pool *pool,
+                                      struct srp_event_struct *evt)
+{
+       if (!valid_event_struct(pool, evt)) {
+               dev_err(evt->hostdata->dev, "Freeing invalid event_struct %p "
+                       "(not in pool %p)\n", evt, pool->events);
+               return;
+       }
+       if (atomic_inc_return(&evt->free) != 1) {
+               dev_err(evt->hostdata->dev, "Freeing event_struct %p "
+                       "which is not in use!\n", evt);
+               return;
+       }
+}
+
+/**
+ * get_evt_struct: - Gets the next free event in pool
+ * @pool:      event_pool that contains the events to be searched
+ *
+ * Returns the next event in "free" state, and NULL if none are free.
+ * Note that no synchronization is done here, we assume the host_lock
+ * will syncrhonze things.
+*/
+static struct srp_event_struct *get_event_struct(struct event_pool *pool)
+{
+       int i;
+       int poolsize = pool->size;
+       int offset = pool->next;
+
+       for (i = 0; i < poolsize; i++) {
+               offset = (offset + 1) % poolsize;
+               if (!atomic_dec_if_positive(&pool->events[offset].free)) {
+                       pool->next = offset;
+                       return &pool->events[offset];
+               }
+       }
+
+       printk(KERN_ERR "ibmvscsi: found no event struct in pool!\n");
+       return NULL;
+}
+
+/**
+ * init_event_struct: Initialize fields in an event struct that are always 
+ *                    required.
+ * @evt:        The event
+ * @done:       Routine to call when the event is responded to
+ * @format:     SRP or MAD format
+ * @timeout:    timeout value set in the CRQ
+ */
+static void init_event_struct(struct srp_event_struct *evt_struct,
+                             void (*done) (struct srp_event_struct *),
+                             u8 format,
+                             int timeout)
+{
+       evt_struct->cmnd = NULL;
+       evt_struct->cmnd_done = NULL;
+       evt_struct->sync_srp = NULL;
+       evt_struct->crq.format = format;
+       evt_struct->crq.timeout = cpu_to_be16(timeout);
+       evt_struct->done = done;
+}
+
+/* ------------------------------------------------------------
+ * Routines for receiving SCSI responses from the hosting partition
+ */
+
+/**
+ * set_srp_direction: Set the fields in the srp related to data
+ *     direction and number of buffers based on the direction in
+ *     the scsi_cmnd and the number of buffers
+ */
+static void set_srp_direction(struct scsi_cmnd *cmd,
+                             struct srp_cmd *srp_cmd, 
+                             int numbuf)
+{
+       u8 fmt;
+
+       if (numbuf == 0)
+               return;
+       
+       if (numbuf == 1)
+               fmt = SRP_DATA_DESC_DIRECT;
+       else {
+               fmt = SRP_DATA_DESC_INDIRECT;
+               numbuf = min(numbuf, MAX_INDIRECT_BUFS);
+
+               if (cmd->sc_data_direction == DMA_TO_DEVICE)
+                       srp_cmd->data_out_desc_cnt = numbuf;
+               else
+                       srp_cmd->data_in_desc_cnt = numbuf;
+       }
+
+       if (cmd->sc_data_direction == DMA_TO_DEVICE)
+               srp_cmd->buf_fmt = fmt << 4;
+       else
+               srp_cmd->buf_fmt = fmt;
+}
+
+/**
+ * unmap_cmd_data: - Unmap data pointed in srp_cmd based on the format
+ * @cmd:       srp_cmd whose additional_data member will be unmapped
+ * @dev:       device for which the memory is mapped
+ *
+*/
+static void unmap_cmd_data(struct srp_cmd *cmd,
+                          struct srp_event_struct *evt_struct,
+                          struct device *dev)
+{
+       u8 out_fmt, in_fmt;
+
+       out_fmt = cmd->buf_fmt >> 4;
+       in_fmt = cmd->buf_fmt & ((1U << 4) - 1);
+
+       if (out_fmt == SRP_NO_DATA_DESC && in_fmt == SRP_NO_DATA_DESC)
+               return;
+
+       if (evt_struct->cmnd)
+               scsi_dma_unmap(evt_struct->cmnd);
+}
+
+static int map_sg_list(struct scsi_cmnd *cmd, int nseg,
+                      struct srp_direct_buf *md)
+{
+       int i;
+       struct scatterlist *sg;
+       u64 total_length = 0;
+
+       scsi_for_each_sg(cmd, sg, nseg, i) {
+               struct srp_direct_buf *descr = md + i;
+               descr->va = cpu_to_be64(sg_dma_address(sg));
+               descr->len = cpu_to_be32(sg_dma_len(sg));
+               descr->key = 0;
+               total_length += sg_dma_len(sg);
+       }
+       return total_length;
+}
+
+/**
+ * map_sg_data: - Maps dma for a scatterlist and initializes decriptor fields
+ * @cmd:       Scsi_Cmnd with the scatterlist
+ * @srp_cmd:   srp_cmd that contains the memory descriptor
+ * @dev:       device for which to map dma memory
+ *
+ * Called by map_data_for_srp_cmd() when building srp cmd from scsi cmd.
+ * Returns 1 on success.
+*/
+static int map_sg_data(struct scsi_cmnd *cmd,
+                      struct srp_event_struct *evt_struct,
+                      struct srp_cmd *srp_cmd, struct device *dev)
+{
+
+       int sg_mapped;
+       u64 total_length = 0;
+       struct srp_direct_buf *data =
+               (struct srp_direct_buf *) srp_cmd->add_data;
+       struct srp_indirect_buf *indirect =
+               (struct srp_indirect_buf *) data;
+
+       sg_mapped = scsi_dma_map(cmd);
+       if (!sg_mapped)
+               return 1;
+       else if (sg_mapped < 0)
+               return 0;
+
+       set_srp_direction(cmd, srp_cmd, sg_mapped);
+
+       /* special case; we can use a single direct descriptor */
+       if (sg_mapped == 1) {
+               map_sg_list(cmd, sg_mapped, data);
+               return 1;
+       }
+
+       indirect->table_desc.va = 0;
+       indirect->table_desc.len = cpu_to_be32(sg_mapped *
+                                              sizeof(struct srp_direct_buf));
+       indirect->table_desc.key = 0;
+
+       if (sg_mapped <= MAX_INDIRECT_BUFS) {
+               total_length = map_sg_list(cmd, sg_mapped,
+                                          &indirect->desc_list[0]);
+               indirect->len = cpu_to_be32(total_length);
+               return 1;
+       }
+
+       /* get indirect table */
+       if (!evt_struct->ext_list) {
+               evt_struct->ext_list = (struct srp_direct_buf *)
+                       dma_alloc_coherent(dev,
+                                          SG_ALL * sizeof(struct srp_direct_buf),
+                                          &evt_struct->ext_list_token, 0);
+               if (!evt_struct->ext_list) {
+                       if (!firmware_has_feature(FW_FEATURE_CMO))
+                               sdev_printk(KERN_ERR, cmd->device,
+                                           "Can't allocate memory "
+                                           "for indirect table\n");
+                       scsi_dma_unmap(cmd);
+                       return 0;
+               }
+       }
+
+       total_length = map_sg_list(cmd, sg_mapped, evt_struct->ext_list);
+
+       indirect->len = cpu_to_be32(total_length);
+       indirect->table_desc.va = cpu_to_be64(evt_struct->ext_list_token);
+       indirect->table_desc.len = cpu_to_be32(sg_mapped *
+                                              sizeof(indirect->desc_list[0]));
+       memcpy(indirect->desc_list, evt_struct->ext_list,
+              MAX_INDIRECT_BUFS * sizeof(struct srp_direct_buf));
+       return 1;
+}
+
+/**
+ * map_data_for_srp_cmd: - Calls functions to map data for srp cmds
+ * @cmd:       struct scsi_cmnd with the memory to be mapped
+ * @srp_cmd:   srp_cmd that contains the memory descriptor
+ * @dev:       dma device for which to map dma memory
+ *
+ * Called by scsi_cmd_to_srp_cmd() when converting scsi cmds to srp cmds 
+ * Returns 1 on success.
+*/
+static int map_data_for_srp_cmd(struct scsi_cmnd *cmd,
+                               struct srp_event_struct *evt_struct,
+                               struct srp_cmd *srp_cmd, struct device *dev)
+{
+       switch (cmd->sc_data_direction) {
+       case DMA_FROM_DEVICE:
+       case DMA_TO_DEVICE:
+               break;
+       case DMA_NONE:
+               return 1;
+       case DMA_BIDIRECTIONAL:
+               sdev_printk(KERN_ERR, cmd->device,
+                           "Can't map DMA_BIDIRECTIONAL to read/write\n");
+               return 0;
+       default:
+               sdev_printk(KERN_ERR, cmd->device,
+                           "Unknown data direction 0x%02x; can't map!\n",
+                           cmd->sc_data_direction);
+               return 0;
+       }
+
+       return map_sg_data(cmd, evt_struct, srp_cmd, dev);
+}
+
+/**
+ * purge_requests: Our virtual adapter just shut down.  purge any sent requests
+ * @hostdata:    the adapter
+ */
+static void purge_requests(struct ibmvscsi_host_data *hostdata, int error_code)
+{
+       struct srp_event_struct *evt;
+       unsigned long flags;
+
+       spin_lock_irqsave(hostdata->host->host_lock, flags);
+       while (!list_empty(&hostdata->sent)) {
+               evt = list_first_entry(&hostdata->sent, struct srp_event_struct, list);
+               list_del(&evt->list);
+               del_timer(&evt->timer);
+
+               spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+               if (evt->cmnd) {
+                       evt->cmnd->result = (error_code << 16);
+                       unmap_cmd_data(&evt->iu.srp.cmd, evt,
+                                      evt->hostdata->dev);
+                       if (evt->cmnd_done)
+                               evt->cmnd_done(evt->cmnd);
+               } else if (evt->done && evt->crq.format != VIOSRP_MAD_FORMAT &&
+                          evt->iu.srp.login_req.opcode != SRP_LOGIN_REQ)
+                       evt->done(evt);
+               free_event_struct(&evt->hostdata->pool, evt);
+               spin_lock_irqsave(hostdata->host->host_lock, flags);
+       }
+       spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+}
+
+/**
+ * ibmvscsi_reset_host - Reset the connection to the server
+ * @hostdata:  struct ibmvscsi_host_data to reset
+*/
+static void ibmvscsi_reset_host(struct ibmvscsi_host_data *hostdata)
+{
+       scsi_block_requests(hostdata->host);
+       atomic_set(&hostdata->request_limit, 0);
+
+       purge_requests(hostdata, DID_ERROR);
+       hostdata->reset_crq = 1;
+       wake_up(&hostdata->work_wait_q);
+}
+
+/**
+ * ibmvscsi_timeout - Internal command timeout handler
+ * @evt_struct:        struct srp_event_struct that timed out
+ *
+ * Called when an internally generated command times out
+*/
+static void ibmvscsi_timeout(struct srp_event_struct *evt_struct)
+{
+       struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;
+
+       dev_err(hostdata->dev, "Command timed out (%x). Resetting connection\n",
+               evt_struct->iu.srp.cmd.opcode);
+
+       ibmvscsi_reset_host(hostdata);
+}
+
+
+/* ------------------------------------------------------------
+ * Routines for sending and receiving SRPs
+ */
+/**
+ * ibmvscsi_send_srp_event: - Transforms event to u64 array and calls send_crq()
+ * @evt_struct:        evt_struct to be sent
+ * @hostdata:  ibmvscsi_host_data of host
+ * @timeout:   timeout in seconds - 0 means do not time command
+ *
+ * Returns the value returned from ibmvscsi_send_crq(). (Zero for success)
+ * Note that this routine assumes that host_lock is held for synchronization
+*/
+static int ibmvscsi_send_srp_event(struct srp_event_struct *evt_struct,
+                                  struct ibmvscsi_host_data *hostdata,
+                                  unsigned long timeout)
+{
+       __be64 *crq_as_u64 = (__be64 *)&evt_struct->crq;
+       int request_status = 0;
+       int rc;
+       int srp_req = 0;
+
+       /* If we have exhausted our request limit, just fail this request,
+        * unless it is for a reset or abort.
+        * Note that there are rare cases involving driver generated requests 
+        * (such as task management requests) that the mid layer may think we
+        * can handle more requests (can_queue) when we actually can't
+        */
+       if (evt_struct->crq.format == VIOSRP_SRP_FORMAT) {
+               srp_req = 1;
+               request_status =
+                       atomic_dec_if_positive(&hostdata->request_limit);
+               /* If request limit was -1 when we started, it is now even
+                * less than that
+                */
+               if (request_status < -1)
+                       goto send_error;
+               /* Otherwise, we may have run out of requests. */
+               /* If request limit was 0 when we started the adapter is in the
+                * process of performing a login with the server adapter, or
+                * we may have run out of requests.
+                */
+               else if (request_status == -1 &&
+                        evt_struct->iu.srp.login_req.opcode != SRP_LOGIN_REQ)
+                       goto send_busy;
+               /* Abort and reset calls should make it through.
+                * Nothing except abort and reset should use the last two
+                * slots unless we had two or less to begin with.
+                */
+               else if (request_status < 2 &&
+                        evt_struct->iu.srp.cmd.opcode != SRP_TSK_MGMT) {
+                       /* In the case that we have less than two requests
+                        * available, check the server limit as a combination
+                        * of the request limit and the number of requests
+                        * in-flight (the size of the send list).  If the
+                        * server limit is greater than 2, return busy so
+                        * that the last two are reserved for reset and abort.
+                        */
+                       int server_limit = request_status;
+                       struct srp_event_struct *tmp_evt;
+
+                       list_for_each_entry(tmp_evt, &hostdata->sent, list) {
+                               server_limit++;
+                       }
+
+                       if (server_limit > 2)
+                               goto send_busy;
+               }
+       }
+
+       /* Copy the IU into the transfer area */
+       *evt_struct->xfer_iu = evt_struct->iu;
+       evt_struct->xfer_iu->srp.rsp.tag = (u64)evt_struct;
+
+       /* Add this to the sent list.  We need to do this 
+        * before we actually send 
+        * in case it comes back REALLY fast
+        */
+       list_add_tail(&evt_struct->list, &hostdata->sent);
+
+       init_timer(&evt_struct->timer);
+       if (timeout) {
+               evt_struct->timer.data = (unsigned long) evt_struct;
+               evt_struct->timer.expires = jiffies + (timeout * HZ);
+               evt_struct->timer.function = (void (*)(unsigned long))ibmvscsi_timeout;
+               add_timer(&evt_struct->timer);
+       }
+
+       rc = ibmvscsi_send_crq(hostdata, be64_to_cpu(crq_as_u64[0]),
+                              be64_to_cpu(crq_as_u64[1]));
+       if (rc != 0) {
+               list_del(&evt_struct->list);
+               del_timer(&evt_struct->timer);
+
+               /* If send_crq returns H_CLOSED, return SCSI_MLQUEUE_HOST_BUSY.
+                * Firmware will send a CRQ with a transport event (0xFF) to
+                * tell this client what has happened to the transport.  This
+                * will be handled in ibmvscsi_handle_crq()
+                */
+               if (rc == H_CLOSED) {
+                       dev_warn(hostdata->dev, "send warning. "
+                                "Receive queue closed, will retry.\n");
+                       goto send_busy;
+               }
+               dev_err(hostdata->dev, "send error %d\n", rc);
+               if (srp_req)
+                       atomic_inc(&hostdata->request_limit);
+               goto send_error;
+       }
+
+       return 0;
+
+ send_busy:
+       unmap_cmd_data(&evt_struct->iu.srp.cmd, evt_struct, hostdata->dev);
+
+       free_event_struct(&hostdata->pool, evt_struct);
+       if (srp_req && request_status != -1)
+               atomic_inc(&hostdata->request_limit);
+       return SCSI_MLQUEUE_HOST_BUSY;
+
+ send_error:
+       unmap_cmd_data(&evt_struct->iu.srp.cmd, evt_struct, hostdata->dev);
+
+       if (evt_struct->cmnd != NULL) {
+               evt_struct->cmnd->result = DID_ERROR << 16;
+               evt_struct->cmnd_done(evt_struct->cmnd);
+       } else if (evt_struct->done)
+               evt_struct->done(evt_struct);
+
+       free_event_struct(&hostdata->pool, evt_struct);
+       return 0;
+}
+
+/**
+ * handle_cmd_rsp: -  Handle responses from commands
+ * @evt_struct:        srp_event_struct to be handled
+ *
+ * Used as a callback by when sending scsi cmds.
+ * Gets called by ibmvscsi_handle_crq()
+*/
+static void handle_cmd_rsp(struct srp_event_struct *evt_struct)
+{
+       struct srp_rsp *rsp = &evt_struct->xfer_iu->srp.rsp;
+       struct scsi_cmnd *cmnd = evt_struct->cmnd;
+
+       if (unlikely(rsp->opcode != SRP_RSP)) {
+               if (printk_ratelimit())
+                       dev_warn(evt_struct->hostdata->dev,
+                                "bad SRP RSP type %d\n", rsp->opcode);
+       }
+       
+       if (cmnd) {
+               cmnd->result |= rsp->status;
+               if (((cmnd->result >> 1) & 0x1f) == CHECK_CONDITION)
+                       memcpy(cmnd->sense_buffer,
+                              rsp->data,
+                              be32_to_cpu(rsp->sense_data_len));
+               unmap_cmd_data(&evt_struct->iu.srp.cmd, 
+                              evt_struct, 
+                              evt_struct->hostdata->dev);
+
+               if (rsp->flags & SRP_RSP_FLAG_DOOVER)
+                       scsi_set_resid(cmnd,
+                                      be32_to_cpu(rsp->data_out_res_cnt));
+               else if (rsp->flags & SRP_RSP_FLAG_DIOVER)
+                       scsi_set_resid(cmnd, be32_to_cpu(rsp->data_in_res_cnt));
+       }
+
+       if (evt_struct->cmnd_done)
+               evt_struct->cmnd_done(cmnd);
+}
+
+/**
+ * lun_from_dev: - Returns the lun of the scsi device
+ * @dev:       struct scsi_device
+ *
+*/
+static inline u16 lun_from_dev(struct scsi_device *dev)
+{
+       return (0x2 << 14) | (dev->id << 8) | (dev->channel << 5) | dev->lun;
+}
+
+/**
+ * ibmvscsi_queue: - The queuecommand function of the scsi template 
+ * @cmd:       struct scsi_cmnd to be executed
+ * @done:      Callback function to be called when cmd is completed
+*/
+static int ibmvscsi_queuecommand_lck(struct scsi_cmnd *cmnd,
+                                void (*done) (struct scsi_cmnd *))
+{
+       struct srp_cmd *srp_cmd;
+       struct srp_event_struct *evt_struct;
+       struct srp_indirect_buf *indirect;
+       struct ibmvscsi_host_data *hostdata = shost_priv(cmnd->device->host);
+       u16 lun = lun_from_dev(cmnd->device);
+       u8 out_fmt, in_fmt;
+
+       cmnd->result = (DID_OK << 16);
+       evt_struct = get_event_struct(&hostdata->pool);
+       if (!evt_struct)
+               return SCSI_MLQUEUE_HOST_BUSY;
+
+       /* Set up the actual SRP IU */
+       srp_cmd = &evt_struct->iu.srp.cmd;
+       memset(srp_cmd, 0x00, SRP_MAX_IU_LEN);
+       srp_cmd->opcode = SRP_CMD;
+       memcpy(srp_cmd->cdb, cmnd->cmnd, sizeof(srp_cmd->cdb));
+       srp_cmd->lun = cpu_to_be64(((u64)lun) << 48);
+
+       if (!map_data_for_srp_cmd(cmnd, evt_struct, srp_cmd, hostdata->dev)) {
+               if (!firmware_has_feature(FW_FEATURE_CMO))
+                       sdev_printk(KERN_ERR, cmnd->device,
+                                   "couldn't convert cmd to srp_cmd\n");
+               free_event_struct(&hostdata->pool, evt_struct);
+               return SCSI_MLQUEUE_HOST_BUSY;
+       }
+
+       init_event_struct(evt_struct,
+                         handle_cmd_rsp,
+                         VIOSRP_SRP_FORMAT,
+                         cmnd->request->timeout/HZ);
+
+       evt_struct->cmnd = cmnd;
+       evt_struct->cmnd_done = done;
+
+       /* Fix up dma address of the buffer itself */
+       indirect = (struct srp_indirect_buf *) srp_cmd->add_data;
+       out_fmt = srp_cmd->buf_fmt >> 4;
+       in_fmt = srp_cmd->buf_fmt & ((1U << 4) - 1);
+       if ((in_fmt == SRP_DATA_DESC_INDIRECT ||
+            out_fmt == SRP_DATA_DESC_INDIRECT) &&
+           indirect->table_desc.va == 0) {
+               indirect->table_desc.va =
+                       cpu_to_be64(be64_to_cpu(evt_struct->crq.IU_data_ptr) +
+                       offsetof(struct srp_cmd, add_data) +
+                       offsetof(struct srp_indirect_buf, desc_list));
+       }
+
+       return ibmvscsi_send_srp_event(evt_struct, hostdata, 0);
+}
+
+static DEF_SCSI_QCMD(ibmvscsi_queuecommand)
+
+/* ------------------------------------------------------------
+ * Routines for driver initialization
+ */
+
+/**
+ * map_persist_bufs: - Pre-map persistent data for adapter logins
+ * @hostdata:   ibmvscsi_host_data of host
+ *
+ * Map the capabilities and adapter info DMA buffers to avoid runtime failures.
+ * Return 1 on error, 0 on success.
+ */
+static int map_persist_bufs(struct ibmvscsi_host_data *hostdata)
+{
+
+       hostdata->caps_addr = dma_map_single(hostdata->dev, &hostdata->caps,
+                                            sizeof(hostdata->caps), DMA_BIDIRECTIONAL);
+
+       if (dma_mapping_error(hostdata->dev, hostdata->caps_addr)) {
+               dev_err(hostdata->dev, "Unable to map capabilities buffer!\n");
+               return 1;
+       }
+
+       hostdata->adapter_info_addr = dma_map_single(hostdata->dev,
+                                                    &hostdata->madapter_info,
+                                                    sizeof(hostdata->madapter_info),
+                                                    DMA_BIDIRECTIONAL);
+       if (dma_mapping_error(hostdata->dev, hostdata->adapter_info_addr)) {
+               dev_err(hostdata->dev, "Unable to map adapter info buffer!\n");
+               dma_unmap_single(hostdata->dev, hostdata->caps_addr,
+                                sizeof(hostdata->caps), DMA_BIDIRECTIONAL);
+               return 1;
+       }
+
+       return 0;
+}
+
+/**
+ * unmap_persist_bufs: - Unmap persistent data needed for adapter logins
+ * @hostdata:   ibmvscsi_host_data of host
+ *
+ * Unmap the capabilities and adapter info DMA buffers
+ */
+static void unmap_persist_bufs(struct ibmvscsi_host_data *hostdata)
+{
+       dma_unmap_single(hostdata->dev, hostdata->caps_addr,
+                        sizeof(hostdata->caps), DMA_BIDIRECTIONAL);
+
+       dma_unmap_single(hostdata->dev, hostdata->adapter_info_addr,
+                        sizeof(hostdata->madapter_info), DMA_BIDIRECTIONAL);
+}
+
+/**
+ * login_rsp: - Handle response to SRP login request
+ * @evt_struct:        srp_event_struct with the response
+ *
+ * Used as a "done" callback by when sending srp_login. Gets called
+ * by ibmvscsi_handle_crq()
+*/
+static void login_rsp(struct srp_event_struct *evt_struct)
+{
+       struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;
+       switch (evt_struct->xfer_iu->srp.login_rsp.opcode) {
+       case SRP_LOGIN_RSP:     /* it worked! */
+               break;
+       case SRP_LOGIN_REJ:     /* refused! */
+               dev_info(hostdata->dev, "SRP_LOGIN_REJ reason %u\n",
+                        evt_struct->xfer_iu->srp.login_rej.reason);
+               /* Login failed.  */
+               atomic_set(&hostdata->request_limit, -1);
+               return;
+       default:
+               dev_err(hostdata->dev, "Invalid login response typecode 0x%02x!\n",
+                       evt_struct->xfer_iu->srp.login_rsp.opcode);
+               /* Login failed.  */
+               atomic_set(&hostdata->request_limit, -1);
+               return;
+       }
+
+       dev_info(hostdata->dev, "SRP_LOGIN succeeded\n");
+       hostdata->client_migrated = 0;
+
+       /* Now we know what the real request-limit is.
+        * This value is set rather than added to request_limit because
+        * request_limit could have been set to -1 by this client.
+        */
+       atomic_set(&hostdata->request_limit,
+                  be32_to_cpu(evt_struct->xfer_iu->srp.login_rsp.req_lim_delta));
+
+       /* If we had any pending I/Os, kick them */
+       scsi_unblock_requests(hostdata->host);
+}
+
+/**
+ * send_srp_login: - Sends the srp login
+ * @hostdata:  ibmvscsi_host_data of host
+ *
+ * Returns zero if successful.
+*/
+static int send_srp_login(struct ibmvscsi_host_data *hostdata)
+{
+       int rc;
+       unsigned long flags;
+       struct srp_login_req *login;
+       struct srp_event_struct *evt_struct = get_event_struct(&hostdata->pool);
+
+       BUG_ON(!evt_struct);
+       init_event_struct(evt_struct, login_rsp,
+                         VIOSRP_SRP_FORMAT, login_timeout);
+
+       login = &evt_struct->iu.srp.login_req;
+       memset(login, 0, sizeof(*login));
+       login->opcode = SRP_LOGIN_REQ;
+       login->req_it_iu_len = cpu_to_be32(sizeof(union srp_iu));
+       login->req_buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
+                                        SRP_BUF_FORMAT_INDIRECT);
+
+       spin_lock_irqsave(hostdata->host->host_lock, flags);
+       /* Start out with a request limit of 0, since this is negotiated in
+        * the login request we are just sending and login requests always
+        * get sent by the driver regardless of request_limit.
+        */
+       atomic_set(&hostdata->request_limit, 0);
+
+       rc = ibmvscsi_send_srp_event(evt_struct, hostdata, login_timeout * 2);
+       spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+       dev_info(hostdata->dev, "sent SRP login\n");
+       return rc;
+};
+
+/**
+ * capabilities_rsp: - Handle response to MAD adapter capabilities request
+ * @evt_struct:        srp_event_struct with the response
+ *
+ * Used as a "done" callback by when sending adapter_info.
+ */
+static void capabilities_rsp(struct srp_event_struct *evt_struct)
+{
+       struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;
+
+       if (evt_struct->xfer_iu->mad.capabilities.common.status) {
+               dev_err(hostdata->dev, "error 0x%X getting capabilities info\n",
+                       evt_struct->xfer_iu->mad.capabilities.common.status);
+       } else {
+               if (hostdata->caps.migration.common.server_support !=
+                   cpu_to_be16(SERVER_SUPPORTS_CAP))
+                       dev_info(hostdata->dev, "Partition migration not supported\n");
+
+               if (client_reserve) {
+                       if (hostdata->caps.reserve.common.server_support ==
+                           cpu_to_be16(SERVER_SUPPORTS_CAP))
+                               dev_info(hostdata->dev, "Client reserve enabled\n");
+                       else
+                               dev_info(hostdata->dev, "Client reserve not supported\n");
+               }
+       }
+
+       send_srp_login(hostdata);
+}
+
+/**
+ * send_mad_capabilities: - Sends the mad capabilities request
+ *      and stores the result so it can be retrieved with
+ * @hostdata:  ibmvscsi_host_data of host
+ */
+static void send_mad_capabilities(struct ibmvscsi_host_data *hostdata)
+{
+       struct viosrp_capabilities *req;
+       struct srp_event_struct *evt_struct;
+       unsigned long flags;
+       struct device_node *of_node = hostdata->dev->of_node;
+       const char *location;
+
+       evt_struct = get_event_struct(&hostdata->pool);
+       BUG_ON(!evt_struct);
+
+       init_event_struct(evt_struct, capabilities_rsp,
+                         VIOSRP_MAD_FORMAT, info_timeout);
+
+       req = &evt_struct->iu.mad.capabilities;
+       memset(req, 0, sizeof(*req));
+
+       hostdata->caps.flags = cpu_to_be32(CAP_LIST_SUPPORTED);
+       if (hostdata->client_migrated)
+               hostdata->caps.flags |= cpu_to_be32(CLIENT_MIGRATED);
+
+       strncpy(hostdata->caps.name, dev_name(&hostdata->host->shost_gendev),
+               sizeof(hostdata->caps.name));
+       hostdata->caps.name[sizeof(hostdata->caps.name) - 1] = '\0';
+
+       location = of_get_property(of_node, "ibm,loc-code", NULL);
+       location = location ? location : dev_name(hostdata->dev);
+       strncpy(hostdata->caps.loc, location, sizeof(hostdata->caps.loc));
+       hostdata->caps.loc[sizeof(hostdata->caps.loc) - 1] = '\0';
+
+       req->common.type = cpu_to_be32(VIOSRP_CAPABILITIES_TYPE);
+       req->buffer = cpu_to_be64(hostdata->caps_addr);
+
+       hostdata->caps.migration.common.cap_type =
+                               cpu_to_be32(MIGRATION_CAPABILITIES);
+       hostdata->caps.migration.common.length =
+                               cpu_to_be16(sizeof(hostdata->caps.migration));
+       hostdata->caps.migration.common.server_support =
+                               cpu_to_be16(SERVER_SUPPORTS_CAP);
+       hostdata->caps.migration.ecl = cpu_to_be32(1);
+
+       if (client_reserve) {
+               hostdata->caps.reserve.common.cap_type =
+                                       cpu_to_be32(RESERVATION_CAPABILITIES);
+               hostdata->caps.reserve.common.length =
+                               cpu_to_be16(sizeof(hostdata->caps.reserve));
+               hostdata->caps.reserve.common.server_support =
+                               cpu_to_be16(SERVER_SUPPORTS_CAP);
+               hostdata->caps.reserve.type =
+                               cpu_to_be32(CLIENT_RESERVE_SCSI_2);
+               req->common.length =
+                               cpu_to_be16(sizeof(hostdata->caps));
+       } else
+               req->common.length = cpu_to_be16(sizeof(hostdata->caps) -
+                                               sizeof(hostdata->caps.reserve));
+
+       spin_lock_irqsave(hostdata->host->host_lock, flags);
+       if (ibmvscsi_send_srp_event(evt_struct, hostdata, info_timeout * 2))
+               dev_err(hostdata->dev, "couldn't send CAPABILITIES_REQ!\n");
+       spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+};
+
+/**
+ * fast_fail_rsp: - Handle response to MAD enable fast fail
+ * @evt_struct:        srp_event_struct with the response
+ *
+ * Used as a "done" callback by when sending enable fast fail. Gets called
+ * by ibmvscsi_handle_crq()
+ */
+static void fast_fail_rsp(struct srp_event_struct *evt_struct)
+{
+       struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;
+       u16 status = be16_to_cpu(evt_struct->xfer_iu->mad.fast_fail.common.status);
+
+       if (status == VIOSRP_MAD_NOT_SUPPORTED)
+               dev_err(hostdata->dev, "fast_fail not supported in server\n");
+       else if (status == VIOSRP_MAD_FAILED)
+               dev_err(hostdata->dev, "fast_fail request failed\n");
+       else if (status != VIOSRP_MAD_SUCCESS)
+               dev_err(hostdata->dev, "error 0x%X enabling fast_fail\n", status);
+
+       send_mad_capabilities(hostdata);
+}
+
+/**
+ * init_host - Start host initialization
+ * @hostdata:  ibmvscsi_host_data of host
+ *
+ * Returns zero if successful.
+ */
+static int enable_fast_fail(struct ibmvscsi_host_data *hostdata)
+{
+       int rc;
+       unsigned long flags;
+       struct viosrp_fast_fail *fast_fail_mad;
+       struct srp_event_struct *evt_struct;
+
+       if (!fast_fail) {
+               send_mad_capabilities(hostdata);
+               return 0;
+       }
+
+       evt_struct = get_event_struct(&hostdata->pool);
+       BUG_ON(!evt_struct);
+
+       init_event_struct(evt_struct, fast_fail_rsp, VIOSRP_MAD_FORMAT, info_timeout);
+
+       fast_fail_mad = &evt_struct->iu.mad.fast_fail;
+       memset(fast_fail_mad, 0, sizeof(*fast_fail_mad));
+       fast_fail_mad->common.type = cpu_to_be32(VIOSRP_ENABLE_FAST_FAIL);
+       fast_fail_mad->common.length = cpu_to_be16(sizeof(*fast_fail_mad));
+
+       spin_lock_irqsave(hostdata->host->host_lock, flags);
+       rc = ibmvscsi_send_srp_event(evt_struct, hostdata, info_timeout * 2);
+       spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+       return rc;
+}
+
+/**
+ * adapter_info_rsp: - Handle response to MAD adapter info request
+ * @evt_struct:        srp_event_struct with the response
+ *
+ * Used as a "done" callback by when sending adapter_info. Gets called
+ * by ibmvscsi_handle_crq()
+*/
+static void adapter_info_rsp(struct srp_event_struct *evt_struct)
+{
+       struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;
+
+       if (evt_struct->xfer_iu->mad.adapter_info.common.status) {
+               dev_err(hostdata->dev, "error %d getting adapter info\n",
+                       evt_struct->xfer_iu->mad.adapter_info.common.status);
+       } else {
+               dev_info(hostdata->dev, "host srp version: %s, "
+                        "host partition %s (%d), OS %d, max io %u\n",
+                        hostdata->madapter_info.srp_version,
+                        hostdata->madapter_info.partition_name,
+                        be32_to_cpu(hostdata->madapter_info.partition_number),
+                        be32_to_cpu(hostdata->madapter_info.os_type),
+                        be32_to_cpu(hostdata->madapter_info.port_max_txu[0]));
+               
+               if (hostdata->madapter_info.port_max_txu[0]) 
+                       hostdata->host->max_sectors = 
+                               be32_to_cpu(hostdata->madapter_info.port_max_txu[0]) >> 9;
+               
+               if (be32_to_cpu(hostdata->madapter_info.os_type) == 3 &&
+                   strcmp(hostdata->madapter_info.srp_version, "1.6a") <= 0) {
+                       dev_err(hostdata->dev, "host (Ver. %s) doesn't support large transfers\n",
+                               hostdata->madapter_info.srp_version);
+                       dev_err(hostdata->dev, "limiting scatterlists to %d\n",
+                               MAX_INDIRECT_BUFS);
+                       hostdata->host->sg_tablesize = MAX_INDIRECT_BUFS;
+               }
+
+               if (be32_to_cpu(hostdata->madapter_info.os_type) == 3) {
+                       enable_fast_fail(hostdata);
+                       return;
+               }
+       }
+
+       send_srp_login(hostdata);
+}
+
+/**
+ * send_mad_adapter_info: - Sends the mad adapter info request
+ *      and stores the result so it can be retrieved with
+ *      sysfs.  We COULD consider causing a failure if the
+ *      returned SRP version doesn't match ours.
+ * @hostdata:  ibmvscsi_host_data of host
+ * 
+ * Returns zero if successful.
+*/
+static void send_mad_adapter_info(struct ibmvscsi_host_data *hostdata)
+{
+       struct viosrp_adapter_info *req;
+       struct srp_event_struct *evt_struct;
+       unsigned long flags;
+
+       evt_struct = get_event_struct(&hostdata->pool);
+       BUG_ON(!evt_struct);
+
+       init_event_struct(evt_struct,
+                         adapter_info_rsp,
+                         VIOSRP_MAD_FORMAT,
+                         info_timeout);
+       
+       req = &evt_struct->iu.mad.adapter_info;
+       memset(req, 0x00, sizeof(*req));
+       
+       req->common.type = cpu_to_be32(VIOSRP_ADAPTER_INFO_TYPE);
+       req->common.length = cpu_to_be16(sizeof(hostdata->madapter_info));
+       req->buffer = cpu_to_be64(hostdata->adapter_info_addr);
+
+       spin_lock_irqsave(hostdata->host->host_lock, flags);
+       if (ibmvscsi_send_srp_event(evt_struct, hostdata, info_timeout * 2))
+               dev_err(hostdata->dev, "couldn't send ADAPTER_INFO_REQ!\n");
+       spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+};
+
+/**
+ * init_adapter: Start virtual adapter initialization sequence
+ *
+ */
+static void init_adapter(struct ibmvscsi_host_data *hostdata)
+{
+       send_mad_adapter_info(hostdata);
+}
+
+/**
+ * sync_completion: Signal that a synchronous command has completed
+ * Note that after returning from this call, the evt_struct is freed.
+ * the caller waiting on this completion shouldn't touch the evt_struct
+ * again.
+ */
+static void sync_completion(struct srp_event_struct *evt_struct)
+{
+       /* copy the response back */
+       if (evt_struct->sync_srp)
+               *evt_struct->sync_srp = *evt_struct->xfer_iu;
+       
+       complete(&evt_struct->comp);
+}
+
+/**
+ * ibmvscsi_abort: Abort a command...from scsi host template
+ * send this over to the server and wait synchronously for the response
+ */
+static int ibmvscsi_eh_abort_handler(struct scsi_cmnd *cmd)
+{
+       struct ibmvscsi_host_data *hostdata = shost_priv(cmd->device->host);
+       struct srp_tsk_mgmt *tsk_mgmt;
+       struct srp_event_struct *evt;
+       struct srp_event_struct *tmp_evt, *found_evt;
+       union viosrp_iu srp_rsp;
+       int rsp_rc;
+       unsigned long flags;
+       u16 lun = lun_from_dev(cmd->device);
+       unsigned long wait_switch = 0;
+
+       /* First, find this command in our sent list so we can figure
+        * out the correct tag
+        */
+       spin_lock_irqsave(hostdata->host->host_lock, flags);
+       wait_switch = jiffies + (init_timeout * HZ);
+       do {
+               found_evt = NULL;
+               list_for_each_entry(tmp_evt, &hostdata->sent, list) {
+                       if (tmp_evt->cmnd == cmd) {
+                               found_evt = tmp_evt;
+                               break;
+                       }
+               }
+
+               if (!found_evt) {
+                       spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+                       return SUCCESS;
+               }
+
+               evt = get_event_struct(&hostdata->pool);
+               if (evt == NULL) {
+                       spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+                       sdev_printk(KERN_ERR, cmd->device,
+                               "failed to allocate abort event\n");
+                       return FAILED;
+               }
+       
+               init_event_struct(evt,
+                                 sync_completion,
+                                 VIOSRP_SRP_FORMAT,
+                                 abort_timeout);
+
+               tsk_mgmt = &evt->iu.srp.tsk_mgmt;
+       
+               /* Set up an abort SRP command */
+               memset(tsk_mgmt, 0x00, sizeof(*tsk_mgmt));
+               tsk_mgmt->opcode = SRP_TSK_MGMT;
+               tsk_mgmt->lun = cpu_to_be64(((u64) lun) << 48);
+               tsk_mgmt->tsk_mgmt_func = SRP_TSK_ABORT_TASK;
+               tsk_mgmt->task_tag = (u64) found_evt;
+
+               evt->sync_srp = &srp_rsp;
+
+               init_completion(&evt->comp);
+               rsp_rc = ibmvscsi_send_srp_event(evt, hostdata, abort_timeout * 2);
+
+               if (rsp_rc != SCSI_MLQUEUE_HOST_BUSY)
+                       break;
+
+               spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+               msleep(10);
+               spin_lock_irqsave(hostdata->host->host_lock, flags);
+       } while (time_before(jiffies, wait_switch));
+
+       spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+
+       if (rsp_rc != 0) {
+               sdev_printk(KERN_ERR, cmd->device,
+                           "failed to send abort() event. rc=%d\n", rsp_rc);
+               return FAILED;
+       }
+
+       sdev_printk(KERN_INFO, cmd->device,
+                    "aborting command. lun 0x%llx, tag 0x%llx\n",
+                   (((u64) lun) << 48), (u64) found_evt);
+
+       wait_for_completion(&evt->comp);
+
+       /* make sure we got a good response */
+       if (unlikely(srp_rsp.srp.rsp.opcode != SRP_RSP)) {
+               if (printk_ratelimit())
+                       sdev_printk(KERN_WARNING, cmd->device, "abort bad SRP RSP type %d\n",
+                                   srp_rsp.srp.rsp.opcode);
+               return FAILED;
+       }
+
+       if (srp_rsp.srp.rsp.flags & SRP_RSP_FLAG_RSPVALID)
+               rsp_rc = *((int *)srp_rsp.srp.rsp.data);
+       else
+               rsp_rc = srp_rsp.srp.rsp.status;
+
+       if (rsp_rc) {
+               if (printk_ratelimit())
+                       sdev_printk(KERN_WARNING, cmd->device,
+                                   "abort code %d for task tag 0x%llx\n",
+                                   rsp_rc, tsk_mgmt->task_tag);
+               return FAILED;
+       }
+
+       /* Because we dropped the spinlock above, it's possible
+        * The event is no longer in our list.  Make sure it didn't
+        * complete while we were aborting
+        */
+       spin_lock_irqsave(hostdata->host->host_lock, flags);
+       found_evt = NULL;
+       list_for_each_entry(tmp_evt, &hostdata->sent, list) {
+               if (tmp_evt->cmnd == cmd) {
+                       found_evt = tmp_evt;
+                       break;
+               }
+       }
+
+       if (found_evt == NULL) {
+               spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+               sdev_printk(KERN_INFO, cmd->device, "aborted task tag 0x%llx completed\n",
+                           tsk_mgmt->task_tag);
+               return SUCCESS;
+       }
+
+       sdev_printk(KERN_INFO, cmd->device, "successfully aborted task tag 0x%llx\n",
+                   tsk_mgmt->task_tag);
+
+       cmd->result = (DID_ABORT << 16);
+       list_del(&found_evt->list);
+       unmap_cmd_data(&found_evt->iu.srp.cmd, found_evt,
+                      found_evt->hostdata->dev);
+       free_event_struct(&found_evt->hostdata->pool, found_evt);
+       spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+       atomic_inc(&hostdata->request_limit);
+       return SUCCESS;
+}
+
+/**
+ * ibmvscsi_eh_device_reset_handler: Reset a single LUN...from scsi host 
+ * template send this over to the server and wait synchronously for the 
+ * response
+ */
+static int ibmvscsi_eh_device_reset_handler(struct scsi_cmnd *cmd)
+{
+       struct ibmvscsi_host_data *hostdata = shost_priv(cmd->device->host);
+       struct srp_tsk_mgmt *tsk_mgmt;
+       struct srp_event_struct *evt;
+       struct srp_event_struct *tmp_evt, *pos;
+       union viosrp_iu srp_rsp;
+       int rsp_rc;
+       unsigned long flags;
+       u16 lun = lun_from_dev(cmd->device);
+       unsigned long wait_switch = 0;
+
+       spin_lock_irqsave(hostdata->host->host_lock, flags);
+       wait_switch = jiffies + (init_timeout * HZ);
+       do {
+               evt = get_event_struct(&hostdata->pool);
+               if (evt == NULL) {
+                       spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+                       sdev_printk(KERN_ERR, cmd->device,
+                               "failed to allocate reset event\n");
+                       return FAILED;
+               }
+       
+               init_event_struct(evt,
+                                 sync_completion,
+                                 VIOSRP_SRP_FORMAT,
+                                 reset_timeout);
+
+               tsk_mgmt = &evt->iu.srp.tsk_mgmt;
+
+               /* Set up a lun reset SRP command */
+               memset(tsk_mgmt, 0x00, sizeof(*tsk_mgmt));
+               tsk_mgmt->opcode = SRP_TSK_MGMT;
+               tsk_mgmt->lun = cpu_to_be64(((u64) lun) << 48);
+               tsk_mgmt->tsk_mgmt_func = SRP_TSK_LUN_RESET;
+
+               evt->sync_srp = &srp_rsp;
+
+               init_completion(&evt->comp);
+               rsp_rc = ibmvscsi_send_srp_event(evt, hostdata, reset_timeout * 2);
+
+               if (rsp_rc != SCSI_MLQUEUE_HOST_BUSY)
+                       break;
+
+               spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+               msleep(10);
+               spin_lock_irqsave(hostdata->host->host_lock, flags);
+       } while (time_before(jiffies, wait_switch));
+
+       spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+
+       if (rsp_rc != 0) {
+               sdev_printk(KERN_ERR, cmd->device,
+                           "failed to send reset event. rc=%d\n", rsp_rc);
+               return FAILED;
+       }
+
+       sdev_printk(KERN_INFO, cmd->device, "resetting device. lun 0x%llx\n",
+                   (((u64) lun) << 48));
+
+       wait_for_completion(&evt->comp);
+
+       /* make sure we got a good response */
+       if (unlikely(srp_rsp.srp.rsp.opcode != SRP_RSP)) {
+               if (printk_ratelimit())
+                       sdev_printk(KERN_WARNING, cmd->device, "reset bad SRP RSP type %d\n",
+                                   srp_rsp.srp.rsp.opcode);
+               return FAILED;
+       }
+
+       if (srp_rsp.srp.rsp.flags & SRP_RSP_FLAG_RSPVALID)
+               rsp_rc = *((int *)srp_rsp.srp.rsp.data);
+       else
+               rsp_rc = srp_rsp.srp.rsp.status;
+
+       if (rsp_rc) {
+               if (printk_ratelimit())
+                       sdev_printk(KERN_WARNING, cmd->device,
+                                   "reset code %d for task tag 0x%llx\n",
+                                   rsp_rc, tsk_mgmt->task_tag);
+               return FAILED;
+       }
+
+       /* We need to find all commands for this LUN that have not yet been
+        * responded to, and fail them with DID_RESET
+        */
+       spin_lock_irqsave(hostdata->host->host_lock, flags);
+       list_for_each_entry_safe(tmp_evt, pos, &hostdata->sent, list) {
+               if ((tmp_evt->cmnd) && (tmp_evt->cmnd->device == cmd->device)) {
+                       if (tmp_evt->cmnd)
+                               tmp_evt->cmnd->result = (DID_RESET << 16);
+                       list_del(&tmp_evt->list);
+                       unmap_cmd_data(&tmp_evt->iu.srp.cmd, tmp_evt,
+                                      tmp_evt->hostdata->dev);
+                       free_event_struct(&tmp_evt->hostdata->pool,
+                                                  tmp_evt);
+                       atomic_inc(&hostdata->request_limit);
+                       if (tmp_evt->cmnd_done)
+                               tmp_evt->cmnd_done(tmp_evt->cmnd);
+                       else if (tmp_evt->done)
+                               tmp_evt->done(tmp_evt);
+               }
+       }
+       spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+       return SUCCESS;
+}
+
+/**
+ * ibmvscsi_eh_host_reset_handler - Reset the connection to the server
+ * @cmd:       struct scsi_cmnd having problems
+*/
+static int ibmvscsi_eh_host_reset_handler(struct scsi_cmnd *cmd)
+{
+       unsigned long wait_switch = 0;
+       struct ibmvscsi_host_data *hostdata = shost_priv(cmd->device->host);
+
+       dev_err(hostdata->dev, "Resetting connection due to error recovery\n");
+
+       ibmvscsi_reset_host(hostdata);
+
+       for (wait_switch = jiffies + (init_timeout * HZ);
+            time_before(jiffies, wait_switch) &&
+                    atomic_read(&hostdata->request_limit) < 2;) {
+
+               msleep(10);
+       }
+
+       if (atomic_read(&hostdata->request_limit) <= 0)
+               return FAILED;
+
+       return SUCCESS;
+}
+
+/**
+ * ibmvscsi_handle_crq: - Handles and frees received events in the CRQ
+ * @crq:       Command/Response queue
+ * @hostdata:  ibmvscsi_host_data of host
+ *
+*/
+static void ibmvscsi_handle_crq(struct viosrp_crq *crq,
+                               struct ibmvscsi_host_data *hostdata)
+{
+       long rc;
+       unsigned long flags;
+       /* The hypervisor copies our tag value here so no byteswapping */
+       struct srp_event_struct *evt_struct =
+                       (__force struct srp_event_struct *)crq->IU_data_ptr;
+       switch (crq->valid) {
+       case 0xC0:              /* initialization */
+               switch (crq->format) {
+               case 0x01:      /* Initialization message */
+                       dev_info(hostdata->dev, "partner initialized\n");
+                       /* Send back a response */
+                       rc = ibmvscsi_send_crq(hostdata, 0xC002000000000000LL, 0);
+                       if (rc == 0) {
+                               /* Now login */
+                               init_adapter(hostdata);
+                       } else {
+                               dev_err(hostdata->dev, "Unable to send init rsp. rc=%ld\n", rc);
+                       }
+
+                       break;
+               case 0x02:      /* Initialization response */
+                       dev_info(hostdata->dev, "partner initialization complete\n");
+
+                       /* Now login */
+                       init_adapter(hostdata);
+                       break;
+               default:
+                       dev_err(hostdata->dev, "unknown crq message type: %d\n", crq->format);
+               }
+               return;
+       case 0xFF:      /* Hypervisor telling us the connection is closed */
+               scsi_block_requests(hostdata->host);
+               atomic_set(&hostdata->request_limit, 0);
+               if (crq->format == 0x06) {
+                       /* We need to re-setup the interpartition connection */
+                       dev_info(hostdata->dev, "Re-enabling adapter!\n");
+                       hostdata->client_migrated = 1;
+                       hostdata->reenable_crq = 1;
+                       purge_requests(hostdata, DID_REQUEUE);
+                       wake_up(&hostdata->work_wait_q);
+               } else {
+                       dev_err(hostdata->dev, "Virtual adapter failed rc %d!\n",
+                               crq->format);
+                       ibmvscsi_reset_host(hostdata);
+               }
+               return;
+       case 0x80:              /* real payload */
+               break;
+       default:
+               dev_err(hostdata->dev, "got an invalid message type 0x%02x\n",
+                       crq->valid);
+               return;
+       }
+
+       /* The only kind of payload CRQs we should get are responses to
+        * things we send. Make sure this response is to something we
+        * actually sent
+        */
+       if (!valid_event_struct(&hostdata->pool, evt_struct)) {
+               dev_err(hostdata->dev, "returned correlation_token 0x%p is invalid!\n",
+                      evt_struct);
+               return;
+       }
+
+       if (atomic_read(&evt_struct->free)) {
+               dev_err(hostdata->dev, "received duplicate correlation_token 0x%p!\n",
+                       evt_struct);
+               return;
+       }
+
+       if (crq->format == VIOSRP_SRP_FORMAT)
+               atomic_add(be32_to_cpu(evt_struct->xfer_iu->srp.rsp.req_lim_delta),
+                          &hostdata->request_limit);
+
+       del_timer(&evt_struct->timer);
+
+       if ((crq->status != VIOSRP_OK && crq->status != VIOSRP_OK2) && evt_struct->cmnd)
+               evt_struct->cmnd->result = DID_ERROR << 16;
+       if (evt_struct->done)
+               evt_struct->done(evt_struct);
+       else
+               dev_err(hostdata->dev, "returned done() is NULL; not running it!\n");
+
+       /*
+        * Lock the host_lock before messing with these structures, since we
+        * are running in a task context
+        */
+       spin_lock_irqsave(evt_struct->hostdata->host->host_lock, flags);
+       list_del(&evt_struct->list);
+       free_event_struct(&evt_struct->hostdata->pool, evt_struct);
+       spin_unlock_irqrestore(evt_struct->hostdata->host->host_lock, flags);
+}
+
+/**
+ * ibmvscsi_get_host_config: Send the command to the server to get host
+ * configuration data.  The data is opaque to us.
+ */
+static int ibmvscsi_do_host_config(struct ibmvscsi_host_data *hostdata,
+                                  unsigned char *buffer, int length)
+{
+       struct viosrp_host_config *host_config;
+       struct srp_event_struct *evt_struct;
+       unsigned long flags;
+       dma_addr_t addr;
+       int rc;
+
+       evt_struct = get_event_struct(&hostdata->pool);
+       if (!evt_struct) {
+               dev_err(hostdata->dev, "couldn't allocate event for HOST_CONFIG!\n");
+               return -1;
+       }
+
+       init_event_struct(evt_struct,
+                         sync_completion,
+                         VIOSRP_MAD_FORMAT,
+                         info_timeout);
+
+       host_config = &evt_struct->iu.mad.host_config;
+
+       /* The transport length field is only 16-bit */
+       length = min(0xffff, length);
+
+       /* Set up a lun reset SRP command */
+       memset(host_config, 0x00, sizeof(*host_config));
+       host_config->common.type = cpu_to_be32(VIOSRP_HOST_CONFIG_TYPE);
+       host_config->common.length = cpu_to_be16(length);
+       addr = dma_map_single(hostdata->dev, buffer, length, DMA_BIDIRECTIONAL);
+
+       if (dma_mapping_error(hostdata->dev, addr)) {
+               if (!firmware_has_feature(FW_FEATURE_CMO))
+                       dev_err(hostdata->dev,
+                               "dma_mapping error getting host config\n");
+               free_event_struct(&hostdata->pool, evt_struct);
+               return -1;
+       }
+
+       host_config->buffer = cpu_to_be64(addr);
+
+       init_completion(&evt_struct->comp);
+       spin_lock_irqsave(hostdata->host->host_lock, flags);
+       rc = ibmvscsi_send_srp_event(evt_struct, hostdata, info_timeout * 2);
+       spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+       if (rc == 0)
+               wait_for_completion(&evt_struct->comp);
+       dma_unmap_single(hostdata->dev, addr, length, DMA_BIDIRECTIONAL);
+
+       return rc;
+}
+
+/**
+ * ibmvscsi_slave_configure: Set the "allow_restart" flag for each disk.
+ * @sdev:      struct scsi_device device to configure
+ *
+ * Enable allow_restart for a device if it is a disk.  Adjust the
+ * queue_depth here also as is required by the documentation for
+ * struct scsi_host_template.
+ */
+static int ibmvscsi_slave_configure(struct scsi_device *sdev)
+{
+       struct Scsi_Host *shost = sdev->host;
+       unsigned long lock_flags = 0;
+
+       spin_lock_irqsave(shost->host_lock, lock_flags);
+       if (sdev->type == TYPE_DISK) {
+               sdev->allow_restart = 1;
+               blk_queue_rq_timeout(sdev->request_queue, 120 * HZ);
+       }
+       spin_unlock_irqrestore(shost->host_lock, lock_flags);
+       return 0;
+}
+
+/**
+ * ibmvscsi_change_queue_depth - Change the device's queue depth
+ * @sdev:      scsi device struct
+ * @qdepth:    depth to set
+ * @reason:    calling context
+ *
+ * Return value:
+ *     actual depth set
+ **/
+static int ibmvscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
+{
+       if (qdepth > IBMVSCSI_MAX_CMDS_PER_LUN)
+               qdepth = IBMVSCSI_MAX_CMDS_PER_LUN;
+       return scsi_change_queue_depth(sdev, qdepth);
+}
+
+/* ------------------------------------------------------------
+ * sysfs attributes
+ */
+static ssize_t show_host_vhost_loc(struct device *dev,
+                                  struct device_attribute *attr, char *buf)
+{
+       struct Scsi_Host *shost = class_to_shost(dev);
+       struct ibmvscsi_host_data *hostdata = shost_priv(shost);
+       int len;
+
+       len = snprintf(buf, sizeof(hostdata->caps.loc), "%s\n",
+                      hostdata->caps.loc);
+       return len;
+}
+
+static struct device_attribute ibmvscsi_host_vhost_loc = {
+       .attr = {
+                .name = "vhost_loc",
+                .mode = S_IRUGO,
+                },
+       .show = show_host_vhost_loc,
+};
+
+static ssize_t show_host_vhost_name(struct device *dev,
+                                   struct device_attribute *attr, char *buf)
+{
+       struct Scsi_Host *shost = class_to_shost(dev);
+       struct ibmvscsi_host_data *hostdata = shost_priv(shost);
+       int len;
+
+       len = snprintf(buf, sizeof(hostdata->caps.name), "%s\n",
+                      hostdata->caps.name);
+       return len;
+}
+
+static struct device_attribute ibmvscsi_host_vhost_name = {
+       .attr = {
+                .name = "vhost_name",
+                .mode = S_IRUGO,
+                },
+       .show = show_host_vhost_name,
+};
+
+static ssize_t show_host_srp_version(struct device *dev,
+                                    struct device_attribute *attr, char *buf)
+{
+       struct Scsi_Host *shost = class_to_shost(dev);
+       struct ibmvscsi_host_data *hostdata = shost_priv(shost);
+       int len;
+
+       len = snprintf(buf, PAGE_SIZE, "%s\n",
+                      hostdata->madapter_info.srp_version);
+       return len;
+}
+
+static struct device_attribute ibmvscsi_host_srp_version = {
+       .attr = {
+                .name = "srp_version",
+                .mode = S_IRUGO,
+                },
+       .show = show_host_srp_version,
+};
+
+static ssize_t show_host_partition_name(struct device *dev,
+                                       struct device_attribute *attr,
+                                       char *buf)
+{
+       struct Scsi_Host *shost = class_to_shost(dev);
+       struct ibmvscsi_host_data *hostdata = shost_priv(shost);
+       int len;
+
+       len = snprintf(buf, PAGE_SIZE, "%s\n",
+                      hostdata->madapter_info.partition_name);
+       return len;
+}
+
+static struct device_attribute ibmvscsi_host_partition_name = {
+       .attr = {
+                .name = "partition_name",
+                .mode = S_IRUGO,
+                },
+       .show = show_host_partition_name,
+};
+
+static ssize_t show_host_partition_number(struct device *dev,
+                                         struct device_attribute *attr,
+                                         char *buf)
+{
+       struct Scsi_Host *shost = class_to_shost(dev);
+       struct ibmvscsi_host_data *hostdata = shost_priv(shost);
+       int len;
+
+       len = snprintf(buf, PAGE_SIZE, "%d\n",
+                      hostdata->madapter_info.partition_number);
+       return len;
+}
+
+static struct device_attribute ibmvscsi_host_partition_number = {
+       .attr = {
+                .name = "partition_number",
+                .mode = S_IRUGO,
+                },
+       .show = show_host_partition_number,
+};
+
+static ssize_t show_host_mad_version(struct device *dev,
+                                    struct device_attribute *attr, char *buf)
+{
+       struct Scsi_Host *shost = class_to_shost(dev);
+       struct ibmvscsi_host_data *hostdata = shost_priv(shost);
+       int len;
+
+       len = snprintf(buf, PAGE_SIZE, "%d\n",
+                      hostdata->madapter_info.mad_version);
+       return len;
+}
+
+static struct device_attribute ibmvscsi_host_mad_version = {
+       .attr = {
+                .name = "mad_version",
+                .mode = S_IRUGO,
+                },
+       .show = show_host_mad_version,
+};
+
+static ssize_t show_host_os_type(struct device *dev,
+                                struct device_attribute *attr, char *buf)
+{
+       struct Scsi_Host *shost = class_to_shost(dev);
+       struct ibmvscsi_host_data *hostdata = shost_priv(shost);
+       int len;
+
+       len = snprintf(buf, PAGE_SIZE, "%d\n", hostdata->madapter_info.os_type);
+       return len;
+}
+
+static struct device_attribute ibmvscsi_host_os_type = {
+       .attr = {
+                .name = "os_type",
+                .mode = S_IRUGO,
+                },
+       .show = show_host_os_type,
+};
+
+static ssize_t show_host_config(struct device *dev,
+                               struct device_attribute *attr, char *buf)
+{
+       struct Scsi_Host *shost = class_to_shost(dev);
+       struct ibmvscsi_host_data *hostdata = shost_priv(shost);
+
+       /* returns null-terminated host config data */
+       if (ibmvscsi_do_host_config(hostdata, buf, PAGE_SIZE) == 0)
+               return strlen(buf);
+       else
+               return 0;
+}
+
+static struct device_attribute ibmvscsi_host_config = {
+       .attr = {
+                .name = "config",
+                .mode = S_IRUGO,
+                },
+       .show = show_host_config,
+};
+
+static struct device_attribute *ibmvscsi_attrs[] = {
+       &ibmvscsi_host_vhost_loc,
+       &ibmvscsi_host_vhost_name,
+       &ibmvscsi_host_srp_version,
+       &ibmvscsi_host_partition_name,
+       &ibmvscsi_host_partition_number,
+       &ibmvscsi_host_mad_version,
+       &ibmvscsi_host_os_type,
+       &ibmvscsi_host_config,
+       NULL
+};
+
+/* ------------------------------------------------------------
+ * SCSI driver registration
+ */
+static struct scsi_host_template driver_template = {
+       .module = THIS_MODULE,
+       .name = "IBM POWER Virtual SCSI Adapter " IBMVSCSI_VERSION,
+       .proc_name = "ibmvscsi",
+       .queuecommand = ibmvscsi_queuecommand,
+       .eh_abort_handler = ibmvscsi_eh_abort_handler,
+       .eh_device_reset_handler = ibmvscsi_eh_device_reset_handler,
+       .eh_host_reset_handler = ibmvscsi_eh_host_reset_handler,
+       .slave_configure = ibmvscsi_slave_configure,
+       .change_queue_depth = ibmvscsi_change_queue_depth,
+       .cmd_per_lun = IBMVSCSI_CMDS_PER_LUN_DEFAULT,
+       .can_queue = IBMVSCSI_MAX_REQUESTS_DEFAULT,
+       .this_id = -1,
+       .sg_tablesize = SG_ALL,
+       .use_clustering = ENABLE_CLUSTERING,
+       .shost_attrs = ibmvscsi_attrs,
+};
+
+/**
+ * ibmvscsi_get_desired_dma - Calculate IO memory desired by the driver
+ *
+ * @vdev: struct vio_dev for the device whose desired IO mem is to be returned
+ *
+ * Return value:
+ *     Number of bytes of IO data the driver will need to perform well.
+ */
+static unsigned long ibmvscsi_get_desired_dma(struct vio_dev *vdev)
+{
+       /* iu_storage data allocated in initialize_event_pool */
+       unsigned long desired_io = max_events * sizeof(union viosrp_iu);
+
+       /* add io space for sg data */
+       desired_io += (IBMVSCSI_MAX_SECTORS_DEFAULT * 512 *
+                            IBMVSCSI_CMDS_PER_LUN_DEFAULT);
+
+       return desired_io;
+}
+
+static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
+{
+       int rc;
+       char *action = "reset";
+
+       if (hostdata->reset_crq) {
+               smp_rmb();
+               hostdata->reset_crq = 0;
+
+               rc = ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata);
+               if (!rc)
+                       rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
+               vio_enable_interrupts(to_vio_dev(hostdata->dev));
+       } else if (hostdata->reenable_crq) {
+               smp_rmb();
+               action = "enable";
+               rc = ibmvscsi_reenable_crq_queue(&hostdata->queue, hostdata);
+               hostdata->reenable_crq = 0;
+               if (!rc)
+                       rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
+       } else
+               return;
+
+       if (rc) {
+               atomic_set(&hostdata->request_limit, -1);
+               dev_err(hostdata->dev, "error after %s\n", action);
+       }
+
+       scsi_unblock_requests(hostdata->host);
+}
+
+static int ibmvscsi_work_to_do(struct ibmvscsi_host_data *hostdata)
+{
+       if (kthread_should_stop())
+               return 1;
+       else if (hostdata->reset_crq) {
+               smp_rmb();
+               return 1;
+       } else if (hostdata->reenable_crq) {
+               smp_rmb();
+               return 1;
+       }
+
+       return 0;
+}
+
+static int ibmvscsi_work(void *data)
+{
+       struct ibmvscsi_host_data *hostdata = data;
+       int rc;
+
+       set_user_nice(current, MIN_NICE);
+
+       while (1) {
+               rc = wait_event_interruptible(hostdata->work_wait_q,
+                                             ibmvscsi_work_to_do(hostdata));
+
+               BUG_ON(rc);
+
+               if (kthread_should_stop())
+                       break;
+
+               ibmvscsi_do_work(hostdata);
+       }
+
+       return 0;
+}
+
+/**
+ * Called by bus code for each adapter
+ */
+static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id)
+{
+       struct ibmvscsi_host_data *hostdata;
+       struct Scsi_Host *host;
+       struct device *dev = &vdev->dev;
+       struct srp_rport_identifiers ids;
+       struct srp_rport *rport;
+       unsigned long wait_switch = 0;
+       int rc;
+
+       dev_set_drvdata(&vdev->dev, NULL);
+
+       host = scsi_host_alloc(&driver_template, sizeof(*hostdata));
+       if (!host) {
+               dev_err(&vdev->dev, "couldn't allocate host data\n");
+               goto scsi_host_alloc_failed;
+       }
+
+       host->transportt = ibmvscsi_transport_template;
+       hostdata = shost_priv(host);
+       memset(hostdata, 0x00, sizeof(*hostdata));
+       INIT_LIST_HEAD(&hostdata->sent);
+       init_waitqueue_head(&hostdata->work_wait_q);
+       hostdata->host = host;
+       hostdata->dev = dev;
+       atomic_set(&hostdata->request_limit, -1);
+       hostdata->host->max_sectors = IBMVSCSI_MAX_SECTORS_DEFAULT;
+
+       if (map_persist_bufs(hostdata)) {
+               dev_err(&vdev->dev, "couldn't map persistent buffers\n");
+               goto persist_bufs_failed;
+       }
+
+       hostdata->work_thread = kthread_run(ibmvscsi_work, hostdata, "%s_%d",
+                                           "ibmvscsi", host->host_no);
+
+       if (IS_ERR(hostdata->work_thread)) {
+               dev_err(&vdev->dev, "couldn't initialize kthread. rc=%ld\n",
+                       PTR_ERR(hostdata->work_thread));
+               goto init_crq_failed;
+       }
+
+       rc = ibmvscsi_init_crq_queue(&hostdata->queue, hostdata, max_events);
+       if (rc != 0 && rc != H_RESOURCE) {
+               dev_err(&vdev->dev, "couldn't initialize crq. rc=%d\n", rc);
+               goto kill_kthread;
+       }
+       if (initialize_event_pool(&hostdata->pool, max_events, hostdata) != 0) {
+               dev_err(&vdev->dev, "couldn't initialize event pool\n");
+               goto init_pool_failed;
+       }
+
+       host->max_lun = 8;
+       host->max_id = max_id;
+       host->max_channel = max_channel;
+       host->max_cmd_len = 16;
+
+       if (scsi_add_host(hostdata->host, hostdata->dev))
+               goto add_host_failed;
+
+       /* we don't have a proper target_port_id so let's use the fake one */
+       memcpy(ids.port_id, hostdata->madapter_info.partition_name,
+              sizeof(ids.port_id));
+       ids.roles = SRP_RPORT_ROLE_TARGET;
+       rport = srp_rport_add(host, &ids);
+       if (IS_ERR(rport))
+               goto add_srp_port_failed;
+
+       /* Try to send an initialization message.  Note that this is allowed
+        * to fail if the other end is not acive.  In that case we don't
+        * want to scan
+        */
+       if (ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0) == 0
+           || rc == H_RESOURCE) {
+               /*
+                * Wait around max init_timeout secs for the adapter to finish
+                * initializing. When we are done initializing, we will have a
+                * valid request_limit.  We don't want Linux scanning before
+                * we are ready.
+                */
+               for (wait_switch = jiffies + (init_timeout * HZ);
+                    time_before(jiffies, wait_switch) &&
+                    atomic_read(&hostdata->request_limit) < 2;) {
+
+                       msleep(10);
+               }
+
+               /* if we now have a valid request_limit, initiate a scan */
+               if (atomic_read(&hostdata->request_limit) > 0)
+                       scsi_scan_host(host);
+       }
+
+       dev_set_drvdata(&vdev->dev, hostdata);
+       return 0;
+
+      add_srp_port_failed:
+       scsi_remove_host(hostdata->host);
+      add_host_failed:
+       release_event_pool(&hostdata->pool, hostdata);
+      init_pool_failed:
+       ibmvscsi_release_crq_queue(&hostdata->queue, hostdata, max_events);
+      kill_kthread:
+      kthread_stop(hostdata->work_thread);
+      init_crq_failed:
+       unmap_persist_bufs(hostdata);
+      persist_bufs_failed:
+       scsi_host_put(host);
+      scsi_host_alloc_failed:
+       return -1;
+}
+
+static int ibmvscsi_remove(struct vio_dev *vdev)
+{
+       struct ibmvscsi_host_data *hostdata = dev_get_drvdata(&vdev->dev);
+       unmap_persist_bufs(hostdata);
+       release_event_pool(&hostdata->pool, hostdata);
+       ibmvscsi_release_crq_queue(&hostdata->queue, hostdata,
+                                       max_events);
+
+       kthread_stop(hostdata->work_thread);
+       srp_remove_host(hostdata->host);
+       scsi_remove_host(hostdata->host);
+       scsi_host_put(hostdata->host);
+
+       return 0;
+}
+
+/**
+ * ibmvscsi_resume: Resume from suspend
+ * @dev:       device struct
+ *
+ * We may have lost an interrupt across suspend/resume, so kick the
+ * interrupt handler
+ */
+static int ibmvscsi_resume(struct device *dev)
+{
+       struct ibmvscsi_host_data *hostdata = dev_get_drvdata(dev);
+       vio_disable_interrupts(to_vio_dev(hostdata->dev));
+       tasklet_schedule(&hostdata->srp_task);
+
+       return 0;
+}
+
+/**
+ * ibmvscsi_device_table: Used by vio.c to match devices in the device tree we 
+ * support.
+ */
+static struct vio_device_id ibmvscsi_device_table[] = {
+       {"vscsi", "IBM,v-scsi"},
+       { "", "" }
+};
+MODULE_DEVICE_TABLE(vio, ibmvscsi_device_table);
+
+static struct dev_pm_ops ibmvscsi_pm_ops = {
+       .resume = ibmvscsi_resume
+};
+
+static struct vio_driver ibmvscsi_driver = {
+       .id_table = ibmvscsi_device_table,
+       .probe = ibmvscsi_probe,
+       .remove = ibmvscsi_remove,
+       .get_desired_dma = ibmvscsi_get_desired_dma,
+       .name = "ibmvscsi",
+       .pm = &ibmvscsi_pm_ops,
+};
+
+static struct srp_function_template ibmvscsi_transport_functions = {
+};
+
+int __init ibmvscsi_module_init(void)
+{
+       int ret;
+
+       /* Ensure we have two requests to do error recovery */
+       driver_template.can_queue = max_requests;
+       max_events = max_requests + 2;
+
+       if (!firmware_has_feature(FW_FEATURE_VIO))
+               return -ENODEV;
+
+       ibmvscsi_transport_template =
+               srp_attach_transport(&ibmvscsi_transport_functions);
+       if (!ibmvscsi_transport_template)
+               return -ENOMEM;
+
+       ret = vio_register_driver(&ibmvscsi_driver);
+       if (ret)
+               srp_release_transport(ibmvscsi_transport_template);
+       return ret;
+}
+
+void __exit ibmvscsi_module_exit(void)
+{
+       vio_unregister_driver(&ibmvscsi_driver);
+       srp_release_transport(ibmvscsi_transport_template);
+}
+
+module_init(ibmvscsi_module_init);
+module_exit(ibmvscsi_module_exit);