drivers/usb/storage/uas.c

   1 /*
   2  * USB Attached SCSI
   3  * Note that this is not the same as the USB Mass Storage driver
   4  *
   5  * Copyright Matthew Wilcox for Intel Corp, 2010
   6  * Copyright Sarah Sharp for Intel Corp, 2010
   7  *
   8  * Distributed under the terms of the GNU GPL, version two.
   9  */
  10
  11 #include <linux/blkdev.h>
  12 #include <linux/slab.h>
  13 #include <linux/types.h>
  14 #include <linux/module.h>
  15 #include <linux/usb.h>
  16 #include <linux/usb/hcd.h>
  17 #include <linux/usb/storage.h>
  18 #include <linux/usb/uas.h>
  19
  20 #include <scsi/scsi.h>
  21 #include <scsi/scsi_dbg.h>
  22 #include <scsi/scsi_cmnd.h>
  23 #include <scsi/scsi_device.h>
  24 #include <scsi/scsi_host.h>
  25 #include <scsi/scsi_tcq.h>
  26
  27 /*
  28  * The r00-r01c specs define this version of the SENSE IU data structure.
  29  * It's still in use by several different firmware releases.
  30  */
  31 struct sense_iu_old {
  32         __u8 iu_id;
  33         __u8 rsvd1;
  34         __be16 tag;
  35         __be16 len;
  36         __u8 status;
  37         __u8 service_response;
  38         __u8 sense[SCSI_SENSE_BUFFERSIZE];
  39 };
  40
  41 struct uas_dev_info {
  42         struct usb_interface *intf;
  43         struct usb_device *udev;
  44         int qdepth;
  45         unsigned cmd_pipe, status_pipe, data_in_pipe, data_out_pipe;
  46         unsigned use_streams:1;
  47         unsigned uas_sense_old:1;
  48         struct scsi_cmnd *cmnd;
  49 };
  50
  51 enum {
  52         SUBMIT_STATUS_URB       = (1 << 1),
  53         ALLOC_DATA_IN_URB       = (1 << 2),
  54         SUBMIT_DATA_IN_URB      = (1 << 3),
  55         ALLOC_DATA_OUT_URB      = (1 << 4),
  56         SUBMIT_DATA_OUT_URB     = (1 << 5),
  57         ALLOC_CMD_URB           = (1 << 6),
  58         SUBMIT_CMD_URB          = (1 << 7),
  59         COMMAND_INFLIGHT        = (1 << 8),
  60         DATA_IN_URB_INFLIGHT    = (1 << 9),
  61         DATA_OUT_URB_INFLIGHT   = (1 << 10),
  62         COMMAND_COMPLETED       = (1 << 11),
  63 };
  64
  65 /* Overrides scsi_pointer */
  66 struct uas_cmd_info {
  67         unsigned int state;
  68         unsigned int stream;
  69         struct urb *cmd_urb;
  70         struct urb *data_in_urb;
  71         struct urb *data_out_urb;
  72         struct list_head list;
  73 };
  74
  75 /* I hate forward declarations, but I actually have a loop */
  76 static int uas_submit_urbs(struct scsi_cmnd *cmnd,
  77                                 struct uas_dev_info *devinfo, gfp_t gfp);
  78 static void uas_do_work(struct work_struct *work);
  79
  80 static DECLARE_WORK(uas_work, uas_do_work);
  81 static DEFINE_SPINLOCK(uas_work_lock);
  82 static LIST_HEAD(uas_work_list);
  83
  84 static void uas_do_work(struct work_struct *work)
  85 {
  86         struct uas_cmd_info *cmdinfo;
  87         struct uas_cmd_info *temp;
  88         struct list_head list;
  89         int err;
  90
  91         spin_lock_irq(&uas_work_lock);
  92         list_replace_init(&uas_work_list, &list);
  93         spin_unlock_irq(&uas_work_lock);
  94
  95         list_for_each_entry_safe(cmdinfo, temp, &list, list) {
  96                 struct scsi_pointer *scp = (void *)cmdinfo;
  97                 struct scsi_cmnd *cmnd = container_of(scp,
  98                                                         struct scsi_cmnd, SCp);
  99                 err = uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_NOIO);
 100                 if (err) {
 101                         list_del(&cmdinfo->list);
 102                         spin_lock_irq(&uas_work_lock);
 103                         list_add_tail(&cmdinfo->list, &uas_work_list);
 104                         spin_unlock_irq(&uas_work_lock);
 105                         schedule_work(&uas_work);
 106                 }
 107         }
 108 }
 109
 110 static void uas_sense(struct urb *urb, struct scsi_cmnd *cmnd)
 111 {
 112         struct sense_iu *sense_iu = urb->transfer_buffer;
 113         struct scsi_device *sdev = cmnd->device;
 114
 115         if (urb->actual_length > 16) {
 116                 unsigned len = be16_to_cpup(&sense_iu->len);
 117                 if (len + 16 != urb->actual_length) {
 118                         int newlen = min(len + 16, urb->actual_length) - 16;
 119                         if (newlen < 0)
 120                                 newlen = 0;
 121                         sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
 122                                 "disagrees with IU sense data length %d, "
 123                                 "using %d bytes of sense data\n", __func__,
 124                                         urb->actual_length, len, newlen);
 125                         len = newlen;
 126                 }
 127                 memcpy(cmnd->sense_buffer, sense_iu->sense, len);
 128         }
 129
 130         cmnd->result = sense_iu->status;
 131 }
 132
 133 static void uas_sense_old(struct urb *urb, struct scsi_cmnd *cmnd)
 134 {
 135         struct sense_iu_old *sense_iu = urb->transfer_buffer;
 136         struct scsi_device *sdev = cmnd->device;
 137
 138         if (urb->actual_length > 8) {
 139                 unsigned len = be16_to_cpup(&sense_iu->len) - 2;
 140                 if (len + 8 != urb->actual_length) {
 141                         int newlen = min(len + 8, urb->actual_length) - 8;
 142                         if (newlen < 0)
 143                                 newlen = 0;
 144                         sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
 145                                 "disagrees with IU sense data length %d, "
 146                                 "using %d bytes of sense data\n", __func__,
 147                                         urb->actual_length, len, newlen);
 148                         len = newlen;
 149                 }
 150                 memcpy(cmnd->sense_buffer, sense_iu->sense, len);
 151         }
 152
 153         cmnd->result = sense_iu->status;
 154 }
 155
 156 static void uas_log_cmd_state(struct scsi_cmnd *cmnd, const char *caller)
 157 {
 158         struct uas_cmd_info *ci = (void *)&cmnd->SCp;
 159
 160         scmd_printk(KERN_INFO, cmnd, "%s %p tag %d, inflight:"
 161                     "%s%s%s%s%s%s%s%s%s%s%s\n",
 162                     caller, cmnd, cmnd->request->tag,
 163                     (ci->state & SUBMIT_STATUS_URB)     ? " s-st"  : "",
 164                     (ci->state & ALLOC_DATA_IN_URB)     ? " a-in"  : "",
 165                     (ci->state & SUBMIT_DATA_IN_URB)    ? " s-in"  : "",
 166                     (ci->state & ALLOC_DATA_OUT_URB)    ? " a-out" : "",
 167                     (ci->state & SUBMIT_DATA_OUT_URB)   ? " s-out" : "",
 168                     (ci->state & ALLOC_CMD_URB)         ? " a-cmd" : "",
 169                     (ci->state & SUBMIT_CMD_URB)        ? " s-cmd" : "",
 170                     (ci->state & COMMAND_INFLIGHT)      ? " CMD"   : "",
 171                     (ci->state & DATA_IN_URB_INFLIGHT)  ? " IN"    : "",
 172                     (ci->state & DATA_OUT_URB_INFLIGHT) ? " OUT"   : "",
 173                     (ci->state & COMMAND_COMPLETED)     ? " done"  : "");
 174 }
 175
 176 static int uas_try_complete(struct scsi_cmnd *cmnd, const char *caller)
 177 {
 178         struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
 179
 180         if (cmdinfo->state & (COMMAND_INFLIGHT |
 181                               DATA_IN_URB_INFLIGHT |
 182                               DATA_OUT_URB_INFLIGHT))
 183                 return -EBUSY;
 184         BUG_ON(cmdinfo->state & COMMAND_COMPLETED);
 185         cmdinfo->state |= COMMAND_COMPLETED;
 186         usb_free_urb(cmdinfo->data_in_urb);
 187         usb_free_urb(cmdinfo->data_out_urb);
 188         cmnd->scsi_done(cmnd);
 189         return 0;
 190 }
 191
 192 static void uas_xfer_data(struct urb *urb, struct scsi_cmnd *cmnd,
 193                           unsigned direction)
 194 {
 195         struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
 196         int err;
 197
 198         cmdinfo->state |= direction | SUBMIT_STATUS_URB;
 199         err = uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_ATOMIC);
 200         if (err) {
 201                 spin_lock(&uas_work_lock);
 202                 list_add_tail(&cmdinfo->list, &uas_work_list);
 203                 spin_unlock(&uas_work_lock);
 204                 schedule_work(&uas_work);
 205         }
 206 }
 207
 208 static void uas_stat_cmplt(struct urb *urb)
 209 {
 210         struct iu *iu = urb->transfer_buffer;
 211         struct Scsi_Host *shost = urb->context;
 212         struct uas_dev_info *devinfo = (void *)shost->hostdata[0];
 213         struct scsi_cmnd *cmnd;
 214         struct uas_cmd_info *cmdinfo;
 215         u16 tag;
 216
 217         if (urb->status) {
 218                 dev_err(&urb->dev->dev, "URB BAD STATUS %d\n", urb->status);
 219                 usb_free_urb(urb);
 220                 return;
 221         }
 222
 223         tag = be16_to_cpup(&iu->tag) - 1;
 224         if (tag == 0)
 225                 cmnd = devinfo->cmnd;
 226         else
 227                 cmnd = scsi_host_find_tag(shost, tag - 1);
 228         if (!cmnd) {
 229                 usb_free_urb(urb);
 230                 return;
 231         }
 232         cmdinfo = (void *)&cmnd->SCp;
 233
 234         switch (iu->iu_id) {
 235         case IU_ID_STATUS:
 236                 if (devinfo->cmnd == cmnd)
 237                         devinfo->cmnd = NULL;
 238
 239                 if (urb->actual_length < 16)
 240                         devinfo->uas_sense_old = 1;
 241                 if (devinfo->uas_sense_old)
 242                         uas_sense_old(urb, cmnd);
 243                 else
 244                         uas_sense(urb, cmnd);
 245                 if (cmnd->result != 0) {
 246                         /* cancel data transfers on error */
 247                         if (cmdinfo->state & DATA_IN_URB_INFLIGHT)
 248                                 usb_unlink_urb(cmdinfo->data_in_urb);
 249                         if (cmdinfo->state & DATA_OUT_URB_INFLIGHT)
 250                                 usb_unlink_urb(cmdinfo->data_out_urb);
 251                 }
 252                 cmdinfo->state &= ~COMMAND_INFLIGHT;
 253                 uas_try_complete(cmnd, __func__);
 254                 break;
 255         case IU_ID_READ_READY:
 256                 uas_xfer_data(urb, cmnd, SUBMIT_DATA_IN_URB);
 257                 break;
 258         case IU_ID_WRITE_READY:
 259                 uas_xfer_data(urb, cmnd, SUBMIT_DATA_OUT_URB);
 260                 break;
 261         default:
 262                 scmd_printk(KERN_ERR, cmnd,
 263                         "Bogus IU (%d) received on status pipe\n", iu->iu_id);
 264         }
 265         usb_free_urb(urb);
 266 }
 267
 268 static void uas_data_cmplt(struct urb *urb)
 269 {
 270         struct scsi_cmnd *cmnd = urb->context;
 271         struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
 272         struct scsi_data_buffer *sdb = NULL;
 273
 274         if (cmdinfo->data_in_urb == urb) {
 275                 sdb = scsi_in(cmnd);
 276                 cmdinfo->state &= ~DATA_IN_URB_INFLIGHT;
 277         } else if (cmdinfo->data_out_urb == urb) {
 278                 sdb = scsi_out(cmnd);
 279                 cmdinfo->state &= ~DATA_OUT_URB_INFLIGHT;
 280         }
 281         BUG_ON(sdb == NULL);
 282         if (urb->status) {
 283                 /* error: no data transfered */
 284                 sdb->resid = sdb->length;
 285         } else {
 286                 sdb->resid = sdb->length - urb->actual_length;
 287         }
 288         uas_try_complete(cmnd, __func__);
 289 }
 290
 291 static struct urb *uas_alloc_data_urb(struct uas_dev_info *devinfo, gfp_t gfp,
 292                                       unsigned int pipe, u16 stream_id,
 293                                       struct scsi_cmnd *cmnd,
 294                                       enum dma_data_direction dir)
 295 {
 296         struct usb_device *udev = devinfo->udev;
 297         struct urb *urb = usb_alloc_urb(0, gfp);
 298         struct scsi_data_buffer *sdb = (dir == DMA_FROM_DEVICE)
 299                 ? scsi_in(cmnd) : scsi_out(cmnd);
 300
 301         if (!urb)
 302                 goto out;
 303         usb_fill_bulk_urb(urb, udev, pipe, NULL, sdb->length,
 304                           uas_data_cmplt, cmnd);
 305         if (devinfo->use_streams)
 306                 urb->stream_id = stream_id;
 307         urb->num_sgs = udev->bus->sg_tablesize ? sdb->table.nents : 0;
 308         urb->sg = sdb->table.sgl;
 309  out:
 310         return urb;
 311 }
 312
 313 static struct urb *uas_alloc_sense_urb(struct uas_dev_info *devinfo, gfp_t gfp,
 314                                        struct Scsi_Host *shost, u16 stream_id)
 315 {
 316         struct usb_device *udev = devinfo->udev;
 317         struct urb *urb = usb_alloc_urb(0, gfp);
 318         struct sense_iu *iu;
 319
 320         if (!urb)
 321                 goto out;
 322
 323         iu = kzalloc(sizeof(*iu), gfp);
 324         if (!iu)
 325                 goto free;
 326
 327         usb_fill_bulk_urb(urb, udev, devinfo->status_pipe, iu, sizeof(*iu),
 328                                                 uas_stat_cmplt, shost);
 329         urb->stream_id = stream_id;
 330         urb->transfer_flags |= URB_FREE_BUFFER;
 331  out:
 332         return urb;
 333  free:
 334         usb_free_urb(urb);
 335         return NULL;
 336 }
 337
 338 static struct urb *uas_alloc_cmd_urb(struct uas_dev_info *devinfo, gfp_t gfp,
 339                                         struct scsi_cmnd *cmnd, u16 stream_id)
 340 {
 341         struct usb_device *udev = devinfo->udev;
 342         struct scsi_device *sdev = cmnd->device;
 343         struct urb *urb = usb_alloc_urb(0, gfp);
 344         struct command_iu *iu;
 345         int len;
 346
 347         if (!urb)
 348                 goto out;
 349
 350         len = cmnd->cmd_len - 16;
 351         if (len < 0)
 352                 len = 0;
 353         len = ALIGN(len, 4);
 354         iu = kzalloc(sizeof(*iu) + len, gfp);
 355         if (!iu)
 356                 goto free;
 357
 358         iu->iu_id = IU_ID_COMMAND;
 359         if (blk_rq_tagged(cmnd->request))
 360                 iu->tag = cpu_to_be16(cmnd->request->tag + 2);
 361         else
 362                 iu->tag = cpu_to_be16(1);
 363         iu->prio_attr = UAS_SIMPLE_TAG;
 364         iu->len = len;
 365         int_to_scsilun(sdev->lun, &iu->lun);
 366         memcpy(iu->cdb, cmnd->cmnd, cmnd->cmd_len);
 367
 368         usb_fill_bulk_urb(urb, udev, devinfo->cmd_pipe, iu, sizeof(*iu) + len,
 369                                                         usb_free_urb, NULL);
 370         urb->transfer_flags |= URB_FREE_BUFFER;
 371  out:
 372         return urb;
 373  free:
 374         usb_free_urb(urb);
 375         return NULL;
 376 }
 377
 378 /*
 379  * Why should I request the Status IU before sending the Command IU?  Spec
 380  * says to, but also says the device may receive them in any order.  Seems
 381  * daft to me.
 382  */
 383
 384 static int uas_submit_sense_urb(struct Scsi_Host *shost,
 385                                 gfp_t gfp, unsigned int stream)
 386 {
 387         struct uas_dev_info *devinfo = (void *)shost->hostdata[0];
 388         struct urb *urb;
 389
 390         urb = uas_alloc_sense_urb(devinfo, gfp, shost, stream);
 391         if (!urb)
 392                 return SCSI_MLQUEUE_DEVICE_BUSY;
 393         if (usb_submit_urb(urb, gfp)) {
 394                 shost_printk(KERN_INFO, shost,
 395                              "sense urb submission failure\n");
 396                 usb_free_urb(urb);
 397                 return SCSI_MLQUEUE_DEVICE_BUSY;
 398         }
 399         return 0;
 400 }
 401
 402 static int uas_submit_urbs(struct scsi_cmnd *cmnd,
 403                            struct uas_dev_info *devinfo, gfp_t gfp)
 404 {
 405         struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
 406         int err;
 407
 408         if (cmdinfo->state & SUBMIT_STATUS_URB) {
 409                 err = uas_submit_sense_urb(cmnd->device->host, gfp,
 410                                            cmdinfo->stream);
 411                 if (err) {
 412                         return err;
 413                 }
 414                 cmdinfo->state &= ~SUBMIT_STATUS_URB;
 415         }
 416
 417         if (cmdinfo->state & ALLOC_DATA_IN_URB) {
 418                 cmdinfo->data_in_urb = uas_alloc_data_urb(devinfo, gfp,
 419                                         devinfo->data_in_pipe, cmdinfo->stream,
 420                                         cmnd, DMA_FROM_DEVICE);
 421                 if (!cmdinfo->data_in_urb)
 422                         return SCSI_MLQUEUE_DEVICE_BUSY;
 423                 cmdinfo->state &= ~ALLOC_DATA_IN_URB;
 424         }
 425
 426         if (cmdinfo->state & SUBMIT_DATA_IN_URB) {
 427                 if (usb_submit_urb(cmdinfo->data_in_urb, gfp)) {
 428                         scmd_printk(KERN_INFO, cmnd,
 429                                         "data in urb submission failure\n");
 430                         return SCSI_MLQUEUE_DEVICE_BUSY;
 431                 }
 432                 cmdinfo->state &= ~SUBMIT_DATA_IN_URB;
 433                 cmdinfo->state |= DATA_IN_URB_INFLIGHT;
 434         }
 435
 436         if (cmdinfo->state & ALLOC_DATA_OUT_URB) {
 437                 cmdinfo->data_out_urb = uas_alloc_data_urb(devinfo, gfp,
 438                                         devinfo->data_out_pipe, cmdinfo->stream,
 439                                         cmnd, DMA_TO_DEVICE);
 440                 if (!cmdinfo->data_out_urb)
 441                         return SCSI_MLQUEUE_DEVICE_BUSY;
 442                 cmdinfo->state &= ~ALLOC_DATA_OUT_URB;
 443         }
 444
 445         if (cmdinfo->state & SUBMIT_DATA_OUT_URB) {
 446                 if (usb_submit_urb(cmdinfo->data_out_urb, gfp)) {
 447                         scmd_printk(KERN_INFO, cmnd,
 448                                         "data out urb submission failure\n");
 449                         return SCSI_MLQUEUE_DEVICE_BUSY;
 450                 }
 451                 cmdinfo->state &= ~SUBMIT_DATA_OUT_URB;
 452                 cmdinfo->state |= DATA_OUT_URB_INFLIGHT;
 453         }
 454
 455         if (cmdinfo->state & ALLOC_CMD_URB) {
 456                 cmdinfo->cmd_urb = uas_alloc_cmd_urb(devinfo, gfp, cmnd,
 457                                                         cmdinfo->stream);
 458                 if (!cmdinfo->cmd_urb)
 459                         return SCSI_MLQUEUE_DEVICE_BUSY;
 460                 cmdinfo->state &= ~ALLOC_CMD_URB;
 461         }
 462
 463         if (cmdinfo->state & SUBMIT_CMD_URB) {
 464                 if (usb_submit_urb(cmdinfo->cmd_urb, gfp)) {
 465                         scmd_printk(KERN_INFO, cmnd,
 466                                         "cmd urb submission failure\n");
 467                         return SCSI_MLQUEUE_DEVICE_BUSY;
 468                 }
 469                 cmdinfo->state &= ~SUBMIT_CMD_URB;
 470                 cmdinfo->state |= COMMAND_INFLIGHT;
 471         }
 472
 473         return 0;
 474 }
 475
 476 static int uas_queuecommand_lck(struct scsi_cmnd *cmnd,
 477                                         void (*done)(struct scsi_cmnd *))
 478 {
 479         struct scsi_device *sdev = cmnd->device;
 480         struct uas_dev_info *devinfo = sdev->hostdata;
 481         struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
 482         int err;
 483
 484         BUILD_BUG_ON(sizeof(struct uas_cmd_info) > sizeof(struct scsi_pointer));
 485
 486         if (devinfo->cmnd)
 487                 return SCSI_MLQUEUE_DEVICE_BUSY;
 488
 489         if (blk_rq_tagged(cmnd->request)) {
 490                 cmdinfo->stream = cmnd->request->tag + 2;
 491         } else {
 492                 devinfo->cmnd = cmnd;
 493                 cmdinfo->stream = 1;
 494         }
 495
 496         cmnd->scsi_done = done;
 497
 498         cmdinfo->state = SUBMIT_STATUS_URB |
 499                         ALLOC_CMD_URB | SUBMIT_CMD_URB;
 500
 501         switch (cmnd->sc_data_direction) {
 502         case DMA_FROM_DEVICE:
 503                 cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
 504                 break;
 505         case DMA_BIDIRECTIONAL:
 506                 cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
 507         case DMA_TO_DEVICE:
 508                 cmdinfo->state |= ALLOC_DATA_OUT_URB | SUBMIT_DATA_OUT_URB;
 509         case DMA_NONE:
 510                 break;
 511         }
 512
 513         if (!devinfo->use_streams) {
 514                 cmdinfo->state &= ~(SUBMIT_DATA_IN_URB | SUBMIT_DATA_OUT_URB);
 515                 cmdinfo->stream = 0;
 516         }
 517
 518         err = uas_submit_urbs(cmnd, devinfo, GFP_ATOMIC);
 519         if (err) {
 520                 /* If we did nothing, give up now */
 521                 if (cmdinfo->state & SUBMIT_STATUS_URB) {
 522                         return SCSI_MLQUEUE_DEVICE_BUSY;
 523                 }
 524                 spin_lock(&uas_work_lock);
 525                 list_add_tail(&cmdinfo->list, &uas_work_list);
 526                 spin_unlock(&uas_work_lock);
 527                 schedule_work(&uas_work);
 528         }
 529
 530         return 0;
 531 }
 532
 533 static DEF_SCSI_QCMD(uas_queuecommand)
 534
 535 static int uas_eh_abort_handler(struct scsi_cmnd *cmnd)
 536 {
 537         uas_log_cmd_state(cmnd, __func__);
 538
 539 /* XXX: Send ABORT TASK Task Management command */
 540         return FAILED;
 541 }
 542
 543 static int uas_eh_device_reset_handler(struct scsi_cmnd *cmnd)
 544 {
 545         struct scsi_device *sdev = cmnd->device;
 546         sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
 547                                                         cmnd->request->tag);
 548
 549 /* XXX: Send LOGICAL UNIT RESET Task Management command */
 550         return FAILED;
 551 }
 552
 553 static int uas_eh_target_reset_handler(struct scsi_cmnd *cmnd)
 554 {
 555         struct scsi_device *sdev = cmnd->device;
 556         sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
 557                                                         cmnd->request->tag);
 558
 559 /* XXX: Can we reset just the one USB interface?
 560  * Would calling usb_set_interface() have the right effect?
 561  */
 562         return FAILED;
 563 }
 564
 565 static int uas_eh_bus_reset_handler(struct scsi_cmnd *cmnd)
 566 {
 567         struct scsi_device *sdev = cmnd->device;
 568         struct uas_dev_info *devinfo = sdev->hostdata;
 569         struct usb_device *udev = devinfo->udev;
 570
 571         sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
 572                                                         cmnd->request->tag);
 573
 574         if (usb_reset_device(udev))
 575                 return SUCCESS;
 576
 577         return FAILED;
 578 }
 579
 580 static int uas_slave_alloc(struct scsi_device *sdev)
 581 {
 582         sdev->hostdata = (void *)sdev->host->hostdata[0];
 583         return 0;
 584 }
 585
 586 static int uas_slave_configure(struct scsi_device *sdev)
 587 {
 588         struct uas_dev_info *devinfo = sdev->hostdata;
 589         scsi_set_tag_type(sdev, MSG_ORDERED_TAG);
 590         scsi_activate_tcq(sdev, devinfo->qdepth - 2);
 591         return 0;
 592 }
 593
 594 static struct scsi_host_template uas_host_template = {
 595         .module = THIS_MODULE,
 596         .name = "uas",
 597         .queuecommand = uas_queuecommand,
 598         .slave_alloc = uas_slave_alloc,
 599         .slave_configure = uas_slave_configure,
 600         .eh_abort_handler = uas_eh_abort_handler,
 601         .eh_device_reset_handler = uas_eh_device_reset_handler,
 602         .eh_target_reset_handler = uas_eh_target_reset_handler,
 603         .eh_bus_reset_handler = uas_eh_bus_reset_handler,
 604         .can_queue = 65536,     /* Is there a limit on the _host_ ? */
 605         .this_id = -1,
 606         .sg_tablesize = SG_NONE,
 607         .cmd_per_lun = 1,       /* until we override it */
 608         .skip_settle_delay = 1,
 609         .ordered_tag = 1,
 610 };
 611
 612 static struct usb_device_id uas_usb_ids[] = {
 613         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_BULK) },
 614         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_UAS) },
 615         /* 0xaa is a prototype device I happen to have access to */
 616         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, 0xaa) },
 617         { }
 618 };
 619 MODULE_DEVICE_TABLE(usb, uas_usb_ids);
 620
 621 static int uas_is_interface(struct usb_host_interface *intf)
 622 {
 623         return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
 624                 intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
 625                 intf->desc.bInterfaceProtocol == USB_PR_UAS);
 626 }
 627
 628 static int uas_isnt_supported(struct usb_device *udev)
 629 {
 630         struct usb_hcd *hcd = bus_to_hcd(udev->bus);
 631
 632         dev_warn(&udev->dev, "The driver for the USB controller %s does not "
 633                         "support scatter-gather which is\n",
 634                         hcd->driver->description);
 635         dev_warn(&udev->dev, "required by the UAS driver. Please try an"
 636                         "alternative USB controller if you wish to use UAS.\n");
 637         return -ENODEV;
 638 }
 639
 640 static int uas_switch_interface(struct usb_device *udev,
 641                                                 struct usb_interface *intf)
 642 {
 643         int i;
 644         int sg_supported = udev->bus->sg_tablesize != 0;
 645
 646         for (i = 0; i < intf->num_altsetting; i++) {
 647                 struct usb_host_interface *alt = &intf->altsetting[i];
 648
 649                 if (uas_is_interface(alt)) {
 650                         if (!sg_supported)
 651                                 return uas_isnt_supported(udev);
 652                         return usb_set_interface(udev,
 653                                                 alt->desc.bInterfaceNumber,
 654                                                 alt->desc.bAlternateSetting);
 655                 }
 656         }
 657
 658         return -ENODEV;
 659 }
 660
 661 static void uas_configure_endpoints(struct uas_dev_info *devinfo)
 662 {
 663         struct usb_host_endpoint *eps[4] = { };
 664         struct usb_interface *intf = devinfo->intf;
 665         struct usb_device *udev = devinfo->udev;
 666         struct usb_host_endpoint *endpoint = intf->cur_altsetting->endpoint;
 667         unsigned i, n_endpoints = intf->cur_altsetting->desc.bNumEndpoints;
 668
 669         devinfo->uas_sense_old = 0;
 670         devinfo->cmnd = NULL;
 671
 672         for (i = 0; i < n_endpoints; i++) {
 673                 unsigned char *extra = endpoint[i].extra;
 674                 int len = endpoint[i].extralen;
 675                 while (len > 1) {
 676                         if (extra[1] == USB_DT_PIPE_USAGE) {
 677                                 unsigned pipe_id = extra[2];
 678                                 if (pipe_id > 0 && pipe_id < 5)
 679                                         eps[pipe_id - 1] = &endpoint[i];
 680                                 break;
 681                         }
 682                         len -= extra[0];
 683                         extra += extra[0];
 684                 }
 685         }
 686
 687         /*
 688          * Assume that if we didn't find a control pipe descriptor, we're
 689          * using a device with old firmware that happens to be set up like
 690          * this.
 691          */
 692         if (!eps[0]) {
 693                 devinfo->cmd_pipe = usb_sndbulkpipe(udev, 1);
 694                 devinfo->status_pipe = usb_rcvbulkpipe(udev, 1);
 695                 devinfo->data_in_pipe = usb_rcvbulkpipe(udev, 2);
 696                 devinfo->data_out_pipe = usb_sndbulkpipe(udev, 2);
 697
 698                 eps[1] = usb_pipe_endpoint(udev, devinfo->status_pipe);
 699                 eps[2] = usb_pipe_endpoint(udev, devinfo->data_in_pipe);
 700                 eps[3] = usb_pipe_endpoint(udev, devinfo->data_out_pipe);
 701         } else {
 702                 devinfo->cmd_pipe = usb_sndbulkpipe(udev,
 703                                                 eps[0]->desc.bEndpointAddress);
 704                 devinfo->status_pipe = usb_rcvbulkpipe(udev,
 705                                                 eps[1]->desc.bEndpointAddress);
 706                 devinfo->data_in_pipe = usb_rcvbulkpipe(udev,
 707                                                 eps[2]->desc.bEndpointAddress);
 708                 devinfo->data_out_pipe = usb_sndbulkpipe(udev,
 709                                                 eps[3]->desc.bEndpointAddress);
 710         }
 711
 712         devinfo->qdepth = usb_alloc_streams(devinfo->intf, eps + 1, 3, 256,
 713                                                                 GFP_KERNEL);
 714         if (devinfo->qdepth < 0) {
 715                 devinfo->qdepth = 256;
 716                 devinfo->use_streams = 0;
 717         } else {
 718                 devinfo->use_streams = 1;
 719         }
 720 }
 721
 722 static void uas_free_streams(struct uas_dev_info *devinfo)
 723 {
 724         struct usb_device *udev = devinfo->udev;
 725         struct usb_host_endpoint *eps[3];
 726
 727         eps[0] = usb_pipe_endpoint(udev, devinfo->status_pipe);
 728         eps[1] = usb_pipe_endpoint(udev, devinfo->data_in_pipe);
 729         eps[2] = usb_pipe_endpoint(udev, devinfo->data_out_pipe);
 730         usb_free_streams(devinfo->intf, eps, 3, GFP_KERNEL);
 731 }
 732
 733 /*
 734  * XXX: What I'd like to do here is register a SCSI host for each USB host in
 735  * the system.  Follow usb-storage's design of registering a SCSI host for
 736  * each USB device for the moment.  Can implement this by walking up the
 737  * USB hierarchy until we find a USB host.
 738  */
 739 static int uas_probe(struct usb_interface *intf, const struct usb_device_id *id)
 740 {
 741         int result;
 742         struct Scsi_Host *shost;
 743         struct uas_dev_info *devinfo;
 744         struct usb_device *udev = interface_to_usbdev(intf);
 745
 746         if (uas_switch_interface(udev, intf))
 747                 return -ENODEV;
 748
 749         devinfo = kmalloc(sizeof(struct uas_dev_info), GFP_KERNEL);
 750         if (!devinfo)
 751                 return -ENOMEM;
 752
 753         result = -ENOMEM;
 754         shost = scsi_host_alloc(&uas_host_template, sizeof(void *));
 755         if (!shost)
 756                 goto free;
 757
 758         shost->max_cmd_len = 16 + 252;
 759         shost->max_id = 1;
 760         shost->sg_tablesize = udev->bus->sg_tablesize;
 761
 762         devinfo->intf = intf;
 763         devinfo->udev = udev;
 764         uas_configure_endpoints(devinfo);
 765
 766         result = scsi_init_shared_tag_map(shost, devinfo->qdepth - 2);
 767         if (result)
 768                 goto free;
 769
 770         result = scsi_add_host(shost, &intf->dev);
 771         if (result)
 772                 goto deconfig_eps;
 773
 774         shost->hostdata[0] = (unsigned long)devinfo;
 775
 776         scsi_scan_host(shost);
 777         usb_set_intfdata(intf, shost);
 778         return result;
 779
 780 deconfig_eps:
 781         uas_free_streams(devinfo);
 782  free:
 783         kfree(devinfo);
 784         if (shost)
 785                 scsi_host_put(shost);
 786         return result;
 787 }
 788
 789 static int uas_pre_reset(struct usb_interface *intf)
 790 {
 791 /* XXX: Need to return 1 if it's not our device in error handling */
 792         return 0;
 793 }
 794
 795 static int uas_post_reset(struct usb_interface *intf)
 796 {
 797 /* XXX: Need to return 1 if it's not our device in error handling */
 798         return 0;
 799 }
 800
 801 static void uas_disconnect(struct usb_interface *intf)
 802 {
 803         struct Scsi_Host *shost = usb_get_intfdata(intf);
 804         struct uas_dev_info *devinfo = (void *)shost->hostdata[0];
 805
 806         scsi_remove_host(shost);
 807         uas_free_streams(devinfo);
 808         kfree(devinfo);
 809 }
 810
 811 /*
 812  * XXX: Should this plug into libusual so we can auto-upgrade devices from
 813  * Bulk-Only to UAS?
 814  */
 815 static struct usb_driver uas_driver = {
 816         .name = "uas",
 817         .probe = uas_probe,
 818         .disconnect = uas_disconnect,
 819         .pre_reset = uas_pre_reset,
 820         .post_reset = uas_post_reset,
 821         .id_table = uas_usb_ids,
 822 };
 823
 824 module_usb_driver(uas_driver);
 825
 826 MODULE_LICENSE("GPL");
 827 MODULE_AUTHOR("Matthew Wilcox and Sarah Sharp");