drivers/scsi/ibmvscsi/rpa_vscsi.c

   1 /* ------------------------------------------------------------
   2  * rpa_vscsi.c
   3  * (C) Copyright IBM Corporation 1994, 2003
   4  * Authors: Colin DeVilbiss (devilbis@us.ibm.com)
   5  *          Santiago Leon (santil@us.ibm.com)
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
  20  * USA
  21  *
  22  * ------------------------------------------------------------
  23  * RPA-specific functions of the SCSI host adapter for Virtual I/O devices
  24  *
  25  * This driver allows the Linux SCSI peripheral drivers to directly
  26  * access devices in the hosting partition, either on an iSeries
  27  * hypervisor system or a converged hypervisor system.
  28  */
  29
  30 #include <asm/vio.h>
  31 #include <asm/iommu.h>
  32 #include <asm/hvcall.h>
  33 #include <linux/dma-mapping.h>
  34 #include <linux/interrupt.h>
  35 #include "ibmvscsi.h"
  36
  37 /* ------------------------------------------------------------
  38  * Routines for managing the command/response queue
  39  */
  40 /**
  41  * ibmvscsi_handle_event: - Interrupt handler for crq events
  42  * @irq:        number of irq to handle, not used
  43  * @dev_instance: ibmvscsi_host_data of host that received interrupt
  44  * @regs:       pt_regs with registers
  45  *
  46  * Disables interrupts and schedules srp_task
  47  * Always returns IRQ_HANDLED
  48  */
  49 static irqreturn_t ibmvscsi_handle_event(int irq,
  50                                          void *dev_instance,
  51                                          struct pt_regs *regs)
  52 {
  53         struct ibmvscsi_host_data *hostdata =
  54             (struct ibmvscsi_host_data *)dev_instance;
  55         vio_disable_interrupts(to_vio_dev(hostdata->dev));
  56         tasklet_schedule(&hostdata->srp_task);
  57         return IRQ_HANDLED;
  58 }
  59
  60 /**
  61  * release_crq_queue: - Deallocates data and unregisters CRQ
  62  * @queue:      crq_queue to initialize and register
  63  * @host_data:  ibmvscsi_host_data of host
  64  *
  65  * Frees irq, deallocates a page for messages, unmaps dma, and unregisters
  66  * the crq with the hypervisor.
  67  */
  68 void ibmvscsi_release_crq_queue(struct crq_queue *queue,
  69                                 struct ibmvscsi_host_data *hostdata,
  70                                 int max_requests)
  71 {
  72         long rc;
  73         struct vio_dev *vdev = to_vio_dev(hostdata->dev);
  74         free_irq(vdev->irq, (void *)hostdata);
  75         tasklet_kill(&hostdata->srp_task);
  76         do {
  77                 rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
  78         } while ((rc == H_Busy) || (H_isLongBusy(rc)));
  79         dma_unmap_single(hostdata->dev,
  80                          queue->msg_token,
  81                          queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
  82         free_page((unsigned long)queue->msgs);
  83 }
  84
  85 /**
  86  * crq_queue_next_crq: - Returns the next entry in message queue
  87  * @queue:      crq_queue to use
  88  *
  89  * Returns pointer to next entry in queue, or NULL if there are no new
  90  * entried in the CRQ.
  91  */
  92 static struct viosrp_crq *crq_queue_next_crq(struct crq_queue *queue)
  93 {
  94         struct viosrp_crq *crq;
  95         unsigned long flags;
  96
  97         spin_lock_irqsave(&queue->lock, flags);
  98         crq = &queue->msgs[queue->cur];
  99         if (crq->valid & 0x80) {
 100                 if (++queue->cur == queue->size)
 101                         queue->cur = 0;
 102         } else
 103                 crq = NULL;
 104         spin_unlock_irqrestore(&queue->lock, flags);
 105
 106         return crq;
 107 }
 108
 109 /**
 110  * ibmvscsi_send_crq: - Send a CRQ
 111  * @hostdata:   the adapter
 112  * @word1:      the first 64 bits of the data
 113  * @word2:      the second 64 bits of the data
 114  */
 115 int ibmvscsi_send_crq(struct ibmvscsi_host_data *hostdata, u64 word1, u64 word2)
 116 {
 117         struct vio_dev *vdev = to_vio_dev(hostdata->dev);
 118
 119         return plpar_hcall_norets(H_SEND_CRQ, vdev->unit_address, word1, word2);
 120 }
 121
 122 /**
 123  * ibmvscsi_task: - Process srps asynchronously
 124  * @data:       ibmvscsi_host_data of host
 125  */
 126 static void ibmvscsi_task(void *data)
 127 {
 128         struct ibmvscsi_host_data *hostdata = (struct ibmvscsi_host_data *)data;
 129         struct vio_dev *vdev = to_vio_dev(hostdata->dev);
 130         struct viosrp_crq *crq;
 131         int done = 0;
 132
 133         while (!done) {
 134                 /* Pull all the valid messages off the CRQ */
 135                 while ((crq = crq_queue_next_crq(&hostdata->queue)) != NULL) {
 136                         ibmvscsi_handle_crq(crq, hostdata);
 137                         crq->valid = 0x00;
 138                 }
 139
 140                 vio_enable_interrupts(vdev);
 141                 if ((crq = crq_queue_next_crq(&hostdata->queue)) != NULL) {
 142                         vio_disable_interrupts(vdev);
 143                         ibmvscsi_handle_crq(crq, hostdata);
 144                         crq->valid = 0x00;
 145                 } else {
 146                         done = 1;
 147                 }
 148         }
 149 }
 150
 151 /**
 152  * initialize_crq_queue: - Initializes and registers CRQ with hypervisor
 153  * @queue:      crq_queue to initialize and register
 154  * @hostdata:   ibmvscsi_host_data of host
 155  *
 156  * Allocates a page for messages, maps it for dma, and registers
 157  * the crq with the hypervisor.
 158  * Returns zero on success.
 159  */
 160 int ibmvscsi_init_crq_queue(struct crq_queue *queue,
 161                             struct ibmvscsi_host_data *hostdata,
 162                             int max_requests)
 163 {
 164         int rc;
 165         struct vio_dev *vdev = to_vio_dev(hostdata->dev);
 166
 167         queue->msgs = (struct viosrp_crq *)get_zeroed_page(GFP_KERNEL);
 168
 169         if (!queue->msgs)
 170                 goto malloc_failed;
 171         queue->size = PAGE_SIZE / sizeof(*queue->msgs);
 172
 173         queue->msg_token = dma_map_single(hostdata->dev, queue->msgs,
 174                                           queue->size * sizeof(*queue->msgs),
 175                                           DMA_BIDIRECTIONAL);
 176
 177         if (dma_mapping_error(queue->msg_token))
 178                 goto map_failed;
 179
 180         rc = plpar_hcall_norets(H_REG_CRQ,
 181                                 vdev->unit_address,
 182                                 queue->msg_token, PAGE_SIZE);
 183         if (rc == 2) {
 184                 /* Adapter is good, but other end is not ready */
 185                 printk(KERN_WARNING "ibmvscsi: Partner adapter not ready\n");
 186         } else if (rc != 0) {
 187                 printk(KERN_WARNING "ibmvscsi: Error %d opening adapter\n", rc);
 188                 goto reg_crq_failed;
 189         }
 190
 191         if (request_irq(vdev->irq,
 192                         ibmvscsi_handle_event,
 193                         0, "ibmvscsi", (void *)hostdata) != 0) {
 194                 printk(KERN_ERR "ibmvscsi: couldn't register irq 0x%x\n",
 195                        vdev->irq);
 196                 goto req_irq_failed;
 197         }
 198
 199         rc = vio_enable_interrupts(vdev);
 200         if (rc != 0) {
 201                 printk(KERN_ERR "ibmvscsi:  Error %d enabling interrupts!!!\n",
 202                        rc);
 203                 goto req_irq_failed;
 204         }
 205
 206         queue->cur = 0;
 207         queue->lock = SPIN_LOCK_UNLOCKED;
 208
 209         tasklet_init(&hostdata->srp_task, (void *)ibmvscsi_task,
 210                      (unsigned long)hostdata);
 211
 212         return 0;
 213
 214       req_irq_failed:
 215         do {
 216                 rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
 217         } while ((rc == H_Busy) || (H_isLongBusy(rc)));
 218       reg_crq_failed:
 219         dma_unmap_single(hostdata->dev,
 220                          queue->msg_token,
 221                          queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
 222       map_failed:
 223         free_page((unsigned long)queue->msgs);
 224       malloc_failed:
 225         return -1;
 226 }
 227
 228 /**
 229  * reset_crq_queue: - resets a crq after a failure
 230  * @queue:      crq_queue to initialize and register
 231  * @hostdata:   ibmvscsi_host_data of host
 232  *
 233  */
 234 void ibmvscsi_reset_crq_queue(struct crq_queue *queue,
 235                               struct ibmvscsi_host_data *hostdata)
 236 {
 237         int rc;
 238         struct vio_dev *vdev = to_vio_dev(hostdata->dev);
 239
 240         /* Close the CRQ */
 241         do {
 242                 rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
 243         } while ((rc == H_Busy) || (H_isLongBusy(rc)));
 244
 245         /* Clean out the queue */
 246         memset(queue->msgs, 0x00, PAGE_SIZE);
 247         queue->cur = 0;
 248
 249         /* And re-open it again */
 250         rc = plpar_hcall_norets(H_REG_CRQ,
 251                                 vdev->unit_address,
 252                                 queue->msg_token, PAGE_SIZE);
 253         if (rc == 2) {
 254                 /* Adapter is good, but other end is not ready */
 255                 printk(KERN_WARNING "ibmvscsi: Partner adapter not ready\n");
 256         } else if (rc != 0) {
 257                 printk(KERN_WARNING
 258                        "ibmvscsi: couldn't register crq--rc 0x%x\n", rc);
 259         }
 260 }