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
  19 #include <scsi/scsi.h>
  20 #include <scsi/scsi_dbg.h>
  21 #include <scsi/scsi_cmnd.h>
  22 #include <scsi/scsi_device.h>
  23 #include <scsi/scsi_host.h>
  24 #include <scsi/scsi_tcq.h>
  25
  26 /* Common header for all IUs */
  27 struct iu {
  28         __u8 iu_id;
  29         __u8 rsvd1;
  30         __be16 tag;
  31 };
  32
  33 enum {
  34         IU_ID_COMMAND           = 0x01,
  35         IU_ID_STATUS            = 0x03,
  36         IU_ID_RESPONSE          = 0x04,
  37         IU_ID_TASK_MGMT         = 0x05,
  38         IU_ID_READ_READY        = 0x06,
  39         IU_ID_WRITE_READY       = 0x07,
  40 };
  41
  42 struct command_iu {
  43         __u8 iu_id;
  44         __u8 rsvd1;
  45         __be16 tag;
  46         __u8 prio_attr;
  47         __u8 rsvd5;
  48         __u8 len;
  49         __u8 rsvd7;
  50         struct scsi_lun lun;
  51         __u8 cdb[16];   /* XXX: Overflow-checking tools may misunderstand */
  52 };
  53
  54 /*
  55  * Also used for the Read Ready and Write Ready IUs since they have the
  56  * same first four bytes
  57  */
  58 struct sense_iu {
  59         __u8 iu_id;
  60         __u8 rsvd1;
  61         __be16 tag;
  62         __be16 status_qual;
  63         __u8 status;
  64         __u8 rsvd7[7];
  65         __be16 len;
  66         __u8 sense[SCSI_SENSE_BUFFERSIZE];
  67 };
  68
  69 /*
  70  * The r00-r01c specs define this version of the SENSE IU data structure.
  71  * It's still in use by several different firmware releases.
  72  */
  73 struct sense_iu_old {
  74         __u8 iu_id;
  75         __u8 rsvd1;
  76         __be16 tag;
  77         __be16 len;
  78         __u8 status;
  79         __u8 service_response;
  80         __u8 sense[SCSI_SENSE_BUFFERSIZE];
  81 };
  82
  83 enum {
  84         CMD_PIPE_ID             = 1,
  85         STATUS_PIPE_ID          = 2,
  86         DATA_IN_PIPE_ID         = 3,
  87         DATA_OUT_PIPE_ID        = 4,
  88
  89         UAS_SIMPLE_TAG          = 0,
  90         UAS_HEAD_TAG            = 1,
  91         UAS_ORDERED_TAG         = 2,
  92         UAS_ACA                 = 4,
  93 };
  94
  95 struct uas_dev_info {
  96         struct usb_interface *intf;
  97         struct usb_device *udev;
  98         int qdepth;
  99         unsigned cmd_pipe, status_pipe, data_in_pipe, data_out_pipe;
 100         unsigned use_streams:1;
 101         unsigned uas_sense_old:1;
 102         struct scsi_cmnd *cmnd;
 103         struct urb *status_urb; /* used only if stream support is available */
 104 };
 105
 106 enum {
 107         ALLOC_STATUS_URB        = (1 << 0),
 108         SUBMIT_STATUS_URB       = (1 << 1),
 109         ALLOC_DATA_IN_URB       = (1 << 2),
 110         SUBMIT_DATA_IN_URB      = (1 << 3),
 111         ALLOC_DATA_OUT_URB      = (1 << 4),
 112         SUBMIT_DATA_OUT_URB     = (1 << 5),
 113         ALLOC_CMD_URB           = (1 << 6),
 114         SUBMIT_CMD_URB          = (1 << 7),
 115 };
 116
 117 /* Overrides scsi_pointer */
 118 struct uas_cmd_info {
 119         unsigned int state;
 120         unsigned int stream;
 121         struct urb *cmd_urb;
 122         /* status_urb is used only if stream support isn't available */
 123         struct urb *status_urb;
 124         struct urb *data_in_urb;
 125         struct urb *data_out_urb;
 126         struct list_head list;
 127 };
 128
 129 /* I hate forward declarations, but I actually have a loop */
 130 static int uas_submit_urbs(struct scsi_cmnd *cmnd,
 131                                 struct uas_dev_info *devinfo, gfp_t gfp);
 132 static void uas_do_work(struct work_struct *work);
 133
 134 static DECLARE_WORK(uas_work, uas_do_work);
 135 static DEFINE_SPINLOCK(uas_work_lock);
 136 static LIST_HEAD(uas_work_list);
 137
 138 static void uas_do_work(struct work_struct *work)
 139 {
 140         struct uas_cmd_info *cmdinfo;
 141         struct uas_cmd_info *temp;
 142         struct list_head list;
 143         int err;
 144
 145         spin_lock_irq(&uas_work_lock);
 146         list_replace_init(&uas_work_list, &list);
 147         spin_unlock_irq(&uas_work_lock);
 148
 149         list_for_each_entry_safe(cmdinfo, temp, &list, list) {
 150                 struct scsi_pointer *scp = (void *)cmdinfo;
 151                 struct scsi_cmnd *cmnd = container_of(scp,
 152                                                         struct scsi_cmnd, SCp);
 153                 err = uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_NOIO);
 154                 if (err) {
 155                         list_del(&cmdinfo->list);
 156                         spin_lock_irq(&uas_work_lock);
 157                         list_add_tail(&cmdinfo->list, &uas_work_list);
 158                         spin_unlock_irq(&uas_work_lock);
 159                         schedule_work(&uas_work);
 160                 }
 161         }
 162 }
 163
 164 static void uas_sense(struct urb *urb, struct scsi_cmnd *cmnd)
 165 {
 166         struct sense_iu *sense_iu = urb->transfer_buffer;
 167         struct scsi_device *sdev = cmnd->device;
 168
 169         if (urb->actual_length > 16) {
 170                 unsigned len = be16_to_cpup(&sense_iu->len);
 171                 if (len + 16 != urb->actual_length) {
 172                         int newlen = min(len + 16, urb->actual_length) - 16;
 173                         if (newlen < 0)
 174                                 newlen = 0;
 175                         sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
 176                                 "disagrees with IU sense data length %d, "
 177                                 "using %d bytes of sense data\n", __func__,
 178                                         urb->actual_length, len, newlen);
 179                         len = newlen;
 180                 }
 181                 memcpy(cmnd->sense_buffer, sense_iu->sense, len);
 182         }
 183
 184         cmnd->result = sense_iu->status;
 185         cmnd->scsi_done(cmnd);
 186 }
 187
 188 static void uas_sense_old(struct urb *urb, struct scsi_cmnd *cmnd)
 189 {
 190         struct sense_iu_old *sense_iu = urb->transfer_buffer;
 191         struct scsi_device *sdev = cmnd->device;
 192
 193         if (urb->actual_length > 8) {
 194                 unsigned len = be16_to_cpup(&sense_iu->len) - 2;
 195                 if (len + 8 != urb->actual_length) {
 196                         int newlen = min(len + 8, urb->actual_length) - 8;
 197                         if (newlen < 0)
 198                                 newlen = 0;
 199                         sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
 200                                 "disagrees with IU sense data length %d, "
 201                                 "using %d bytes of sense data\n", __func__,
 202                                         urb->actual_length, len, newlen);
 203                         len = newlen;
 204                 }
 205                 memcpy(cmnd->sense_buffer, sense_iu->sense, len);
 206         }
 207
 208         cmnd->result = sense_iu->status;
 209         cmnd->scsi_done(cmnd);
 210 }
 211
 212 static void uas_xfer_data(struct urb *urb, struct scsi_cmnd *cmnd,
 213                                                         unsigned direction)
 214 {
 215         struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
 216         int err;
 217
 218         cmdinfo->state = direction;
 219         err = uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_ATOMIC);
 220         if (err) {
 221                 spin_lock(&uas_work_lock);
 222                 list_add_tail(&cmdinfo->list, &uas_work_list);
 223                 spin_unlock(&uas_work_lock);
 224                 schedule_work(&uas_work);
 225         }
 226 }
 227
 228 static void uas_stat_cmplt(struct urb *urb)
 229 {
 230         struct iu *iu = urb->transfer_buffer;
 231         struct Scsi_Host *shost = urb->context;
 232         struct uas_dev_info *devinfo = (void *)shost->hostdata[0];
 233         struct scsi_cmnd *cmnd;
 234         u16 tag;
 235         int ret;
 236
 237         if (urb->status) {
 238                 dev_err(&urb->dev->dev, "URB BAD STATUS %d\n", urb->status);
 239                 if (devinfo->use_streams)
 240                         usb_free_urb(urb);
 241                 return;
 242         }
 243
 244         tag = be16_to_cpup(&iu->tag) - 1;
 245         if (tag == 0)
 246                 cmnd = devinfo->cmnd;
 247         else
 248                 cmnd = scsi_host_find_tag(shost, tag - 1);
 249         if (!cmnd) {
 250                 if (devinfo->use_streams) {
 251                         usb_free_urb(urb);
 252                         return;
 253                 }
 254                 ret = usb_submit_urb(urb, GFP_ATOMIC);
 255                 if (ret)
 256                         dev_err(&urb->dev->dev, "failed submit status urb\n");
 257                 return;
 258         }
 259
 260         switch (iu->iu_id) {
 261         case IU_ID_STATUS:
 262                 if (devinfo->cmnd == cmnd)
 263                         devinfo->cmnd = NULL;
 264
 265                 if (urb->actual_length < 16)
 266                         devinfo->uas_sense_old = 1;
 267                 if (devinfo->uas_sense_old)
 268                         uas_sense_old(urb, cmnd);
 269                 else
 270                         uas_sense(urb, cmnd);
 271                 break;
 272         case IU_ID_READ_READY:
 273                 uas_xfer_data(urb, cmnd, SUBMIT_DATA_IN_URB);
 274                 break;
 275         case IU_ID_WRITE_READY:
 276                 uas_xfer_data(urb, cmnd, SUBMIT_DATA_OUT_URB);
 277                 break;
 278         default:
 279                 scmd_printk(KERN_ERR, cmnd,
 280                         "Bogus IU (%d) received on status pipe\n", iu->iu_id);
 281         }
 282
 283         if (devinfo->use_streams) {
 284                 usb_free_urb(urb);
 285                 return;
 286         }
 287
 288         ret = usb_submit_urb(urb, GFP_ATOMIC);
 289         if (ret)
 290                 dev_err(&urb->dev->dev, "failed submit status urb\n");
 291 }
 292
 293 static void uas_data_cmplt(struct urb *urb)
 294 {
 295         struct scsi_data_buffer *sdb = urb->context;
 296         sdb->resid = sdb->length - urb->actual_length;
 297         usb_free_urb(urb);
 298 }
 299
 300 static struct urb *uas_alloc_data_urb(struct uas_dev_info *devinfo, gfp_t gfp,
 301                                 unsigned int pipe, u16 stream_id,
 302                                 struct scsi_data_buffer *sdb,
 303                                 enum dma_data_direction dir)
 304 {
 305         struct usb_device *udev = devinfo->udev;
 306         struct urb *urb = usb_alloc_urb(0, gfp);
 307
 308         if (!urb)
 309                 goto out;
 310         usb_fill_bulk_urb(urb, udev, pipe, NULL, sdb->length, uas_data_cmplt,
 311                                                                         sdb);
 312         if (devinfo->use_streams)
 313                 urb->stream_id = stream_id;
 314         urb->num_sgs = udev->bus->sg_tablesize ? sdb->table.nents : 0;
 315         urb->sg = sdb->table.sgl;
 316  out:
 317         return urb;
 318 }
 319
 320 static struct urb *uas_alloc_sense_urb(struct uas_dev_info *devinfo, gfp_t gfp,
 321                 struct Scsi_Host *shost, u16 stream_id)
 322 {
 323         struct usb_device *udev = devinfo->udev;
 324         struct urb *urb = usb_alloc_urb(0, gfp);
 325         struct sense_iu *iu;
 326
 327         if (!urb)
 328                 goto out;
 329
 330         iu = kzalloc(sizeof(*iu), gfp);
 331         if (!iu)
 332                 goto free;
 333
 334         usb_fill_bulk_urb(urb, udev, devinfo->status_pipe, iu, sizeof(*iu),
 335                                                 uas_stat_cmplt, shost);
 336         urb->stream_id = stream_id;
 337         urb->transfer_flags |= URB_FREE_BUFFER;
 338  out:
 339         return urb;
 340  free:
 341         usb_free_urb(urb);
 342         return NULL;
 343 }
 344
 345 static struct urb *uas_alloc_cmd_urb(struct uas_dev_info *devinfo, gfp_t gfp,
 346                                         struct scsi_cmnd *cmnd, u16 stream_id)
 347 {
 348         struct usb_device *udev = devinfo->udev;
 349         struct scsi_device *sdev = cmnd->device;
 350         struct urb *urb = usb_alloc_urb(0, gfp);
 351         struct command_iu *iu;
 352         int len;
 353
 354         if (!urb)
 355                 goto out;
 356
 357         len = cmnd->cmd_len - 16;
 358         if (len < 0)
 359                 len = 0;
 360         len = ALIGN(len, 4);
 361         iu = kzalloc(sizeof(*iu) + len, gfp);
 362         if (!iu)
 363                 goto free;
 364
 365         iu->iu_id = IU_ID_COMMAND;
 366         if (blk_rq_tagged(cmnd->request))
 367                 iu->tag = cpu_to_be16(cmnd->request->tag + 2);
 368         else
 369                 iu->tag = cpu_to_be16(1);
 370         iu->prio_attr = UAS_SIMPLE_TAG;
 371         iu->len = len;
 372         int_to_scsilun(sdev->lun, &iu->lun);
 373         memcpy(iu->cdb, cmnd->cmnd, cmnd->cmd_len);
 374
 375         usb_fill_bulk_urb(urb, udev, devinfo->cmd_pipe, iu, sizeof(*iu) + len,
 376                                                         usb_free_urb, NULL);
 377         urb->transfer_flags |= URB_FREE_BUFFER;
 378  out:
 379         return urb;
 380  free:
 381         usb_free_urb(urb);
 382         return NULL;
 383 }
 384
 385 /*
 386  * Why should I request the Status IU before sending the Command IU?  Spec
 387  * says to, but also says the device may receive them in any order.  Seems
 388  * daft to me.
 389  */
 390
 391 static int uas_submit_urbs(struct scsi_cmnd *cmnd,
 392                                         struct uas_dev_info *devinfo, gfp_t gfp)
 393 {
 394         struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
 395
 396         if (cmdinfo->state & ALLOC_STATUS_URB) {
 397                 cmdinfo->status_urb = uas_alloc_sense_urb(devinfo, gfp,
 398                                 cmnd->device->host, cmdinfo->stream);
 399                 if (!cmdinfo->status_urb)
 400                         return SCSI_MLQUEUE_DEVICE_BUSY;
 401                 cmdinfo->state &= ~ALLOC_STATUS_URB;
 402         }
 403
 404         if (cmdinfo->state & SUBMIT_STATUS_URB) {
 405                 if (usb_submit_urb(cmdinfo->status_urb, gfp)) {
 406                         scmd_printk(KERN_INFO, cmnd,
 407                                         "sense urb submission failure\n");
 408                         return SCSI_MLQUEUE_DEVICE_BUSY;
 409                 }
 410                 cmdinfo->state &= ~SUBMIT_STATUS_URB;
 411         }
 412
 413         if (cmdinfo->state & ALLOC_DATA_IN_URB) {
 414                 cmdinfo->data_in_urb = uas_alloc_data_urb(devinfo, gfp,
 415                                         devinfo->data_in_pipe, cmdinfo->stream,
 416                                         scsi_in(cmnd), DMA_FROM_DEVICE);
 417                 if (!cmdinfo->data_in_urb)
 418                         return SCSI_MLQUEUE_DEVICE_BUSY;
 419                 cmdinfo->state &= ~ALLOC_DATA_IN_URB;
 420         }
 421
 422         if (cmdinfo->state & SUBMIT_DATA_IN_URB) {
 423                 if (usb_submit_urb(cmdinfo->data_in_urb, gfp)) {
 424                         scmd_printk(KERN_INFO, cmnd,
 425                                         "data in urb submission failure\n");
 426                         return SCSI_MLQUEUE_DEVICE_BUSY;
 427                 }
 428                 cmdinfo->state &= ~SUBMIT_DATA_IN_URB;
 429         }
 430
 431         if (cmdinfo->state & ALLOC_DATA_OUT_URB) {
 432                 cmdinfo->data_out_urb = uas_alloc_data_urb(devinfo, gfp,
 433                                         devinfo->data_out_pipe, cmdinfo->stream,
 434                                         scsi_out(cmnd), DMA_TO_DEVICE);
 435                 if (!cmdinfo->data_out_urb)
 436                         return SCSI_MLQUEUE_DEVICE_BUSY;
 437                 cmdinfo->state &= ~ALLOC_DATA_OUT_URB;
 438         }
 439
 440         if (cmdinfo->state & SUBMIT_DATA_OUT_URB) {
 441                 if (usb_submit_urb(cmdinfo->data_out_urb, gfp)) {
 442                         scmd_printk(KERN_INFO, cmnd,
 443                                         "data out urb submission failure\n");
 444                         return SCSI_MLQUEUE_DEVICE_BUSY;
 445                 }
 446                 cmdinfo->state &= ~SUBMIT_DATA_OUT_URB;
 447         }
 448
 449         if (cmdinfo->state & ALLOC_CMD_URB) {
 450                 cmdinfo->cmd_urb = uas_alloc_cmd_urb(devinfo, gfp, cmnd,
 451                                                         cmdinfo->stream);
 452                 if (!cmdinfo->cmd_urb)
 453                         return SCSI_MLQUEUE_DEVICE_BUSY;
 454                 cmdinfo->state &= ~ALLOC_CMD_URB;
 455         }
 456
 457         if (cmdinfo->state & SUBMIT_CMD_URB) {
 458                 if (usb_submit_urb(cmdinfo->cmd_urb, gfp)) {
 459                         scmd_printk(KERN_INFO, cmnd,
 460                                         "cmd urb submission failure\n");
 461                         return SCSI_MLQUEUE_DEVICE_BUSY;
 462                 }
 463                 cmdinfo->state &= ~SUBMIT_CMD_URB;
 464         }
 465
 466         return 0;
 467 }
 468
 469 static int uas_queuecommand_lck(struct scsi_cmnd *cmnd,
 470                                         void (*done)(struct scsi_cmnd *))
 471 {
 472         struct scsi_device *sdev = cmnd->device;
 473         struct uas_dev_info *devinfo = sdev->hostdata;
 474         struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
 475         int err;
 476
 477         BUILD_BUG_ON(sizeof(struct uas_cmd_info) > sizeof(struct scsi_pointer));
 478
 479         if (devinfo->cmnd)
 480                 return SCSI_MLQUEUE_DEVICE_BUSY;
 481
 482         if (blk_rq_tagged(cmnd->request)) {
 483                 cmdinfo->stream = cmnd->request->tag + 2;
 484         } else {
 485                 devinfo->cmnd = cmnd;
 486                 cmdinfo->stream = 1;
 487         }
 488
 489         cmnd->scsi_done = done;
 490
 491         cmdinfo->state = ALLOC_STATUS_URB | SUBMIT_STATUS_URB |
 492                         ALLOC_CMD_URB | SUBMIT_CMD_URB;
 493
 494         switch (cmnd->sc_data_direction) {
 495         case DMA_FROM_DEVICE:
 496                 cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
 497                 break;
 498         case DMA_BIDIRECTIONAL:
 499                 cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
 500         case DMA_TO_DEVICE:
 501                 cmdinfo->state |= ALLOC_DATA_OUT_URB | SUBMIT_DATA_OUT_URB;
 502         case DMA_NONE:
 503                 break;
 504         }
 505
 506         if (!devinfo->use_streams) {
 507                 cmdinfo->state &= ~(SUBMIT_DATA_IN_URB | SUBMIT_DATA_OUT_URB |
 508                                 ALLOC_STATUS_URB | SUBMIT_STATUS_URB);
 509                 cmdinfo->stream = 0;
 510         }
 511
 512         err = uas_submit_urbs(cmnd, devinfo, GFP_ATOMIC);
 513         if (err) {
 514                 /* If we did nothing, give up now */
 515                 if (cmdinfo->state & SUBMIT_STATUS_URB) {
 516                         usb_free_urb(cmdinfo->status_urb);
 517                         return SCSI_MLQUEUE_DEVICE_BUSY;
 518                 }
 519                 spin_lock(&uas_work_lock);
 520                 list_add_tail(&cmdinfo->list, &uas_work_list);
 521                 spin_unlock(&uas_work_lock);
 522                 schedule_work(&uas_work);
 523         }
 524
 525         return 0;
 526 }
 527
 528 static DEF_SCSI_QCMD(uas_queuecommand)
 529
 530 static int uas_eh_abort_handler(struct scsi_cmnd *cmnd)
 531 {
 532         struct scsi_device *sdev = cmnd->device;
 533         sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
 534                                                         cmnd->request->tag);
 535
 536 /* XXX: Send ABORT TASK Task Management command */
 537         return FAILED;
 538 }
 539
 540 static int uas_eh_device_reset_handler(struct scsi_cmnd *cmnd)
 541 {
 542         struct scsi_device *sdev = cmnd->device;
 543         sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
 544                                                         cmnd->request->tag);
 545
 546 /* XXX: Send LOGICAL UNIT RESET Task Management command */
 547         return FAILED;
 548 }
 549
 550 static int uas_eh_target_reset_handler(struct scsi_cmnd *cmnd)
 551 {
 552         struct scsi_device *sdev = cmnd->device;
 553         sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
 554                                                         cmnd->request->tag);
 555
 556 /* XXX: Can we reset just the one USB interface?
 557  * Would calling usb_set_interface() have the right effect?
 558  */
 559         return FAILED;
 560 }
 561
 562 static int uas_eh_bus_reset_handler(struct scsi_cmnd *cmnd)
 563 {
 564         struct scsi_device *sdev = cmnd->device;
 565         struct uas_dev_info *devinfo = sdev->hostdata;
 566         struct usb_device *udev = devinfo->udev;
 567
 568         sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
 569                                                         cmnd->request->tag);
 570
 571         if (usb_reset_device(udev))
 572                 return SUCCESS;
 573
 574         return FAILED;
 575 }
 576
 577 static int uas_slave_alloc(struct scsi_device *sdev)
 578 {
 579         sdev->hostdata = (void *)sdev->host->hostdata[0];
 580         return 0;
 581 }
 582
 583 static int uas_slave_configure(struct scsi_device *sdev)
 584 {
 585         struct uas_dev_info *devinfo = sdev->hostdata;
 586         scsi_set_tag_type(sdev, MSG_ORDERED_TAG);
 587         scsi_activate_tcq(sdev, devinfo->qdepth - 2);
 588         return 0;
 589 }
 590
 591 static struct scsi_host_template uas_host_template = {
 592         .module = THIS_MODULE,
 593         .name = "uas",
 594         .queuecommand = uas_queuecommand,
 595         .slave_alloc = uas_slave_alloc,
 596         .slave_configure = uas_slave_configure,
 597         .eh_abort_handler = uas_eh_abort_handler,
 598         .eh_device_reset_handler = uas_eh_device_reset_handler,
 599         .eh_target_reset_handler = uas_eh_target_reset_handler,
 600         .eh_bus_reset_handler = uas_eh_bus_reset_handler,
 601         .can_queue = 65536,     /* Is there a limit on the _host_ ? */
 602         .this_id = -1,
 603         .sg_tablesize = SG_NONE,
 604         .cmd_per_lun = 1,       /* until we override it */
 605         .skip_settle_delay = 1,
 606         .ordered_tag = 1,
 607 };
 608
 609 static struct usb_device_id uas_usb_ids[] = {
 610         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_BULK) },
 611         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_UAS) },
 612         /* 0xaa is a prototype device I happen to have access to */
 613         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, 0xaa) },
 614         { }
 615 };
 616 MODULE_DEVICE_TABLE(usb, uas_usb_ids);
 617
 618 static int uas_is_interface(struct usb_host_interface *intf)
 619 {
 620         return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
 621                 intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
 622                 intf->desc.bInterfaceProtocol == USB_PR_UAS);
 623 }
 624
 625 static int uas_isnt_supported(struct usb_device *udev)
 626 {
 627         struct usb_hcd *hcd = bus_to_hcd(udev->bus);
 628
 629         dev_warn(&udev->dev, "The driver for the USB controller %s does not "
 630                         "support scatter-gather which is\n",
 631                         hcd->driver->description);
 632         dev_warn(&udev->dev, "required by the UAS driver. Please try an"
 633                         "alternative USB controller if you wish to use UAS.\n");
 634         return -ENODEV;
 635 }
 636
 637 static int uas_switch_interface(struct usb_device *udev,
 638                                                 struct usb_interface *intf)
 639 {
 640         int i;
 641         int sg_supported = udev->bus->sg_tablesize != 0;
 642
 643         for (i = 0; i < intf->num_altsetting; i++) {
 644                 struct usb_host_interface *alt = &intf->altsetting[i];
 645
 646                 if (uas_is_interface(alt)) {
 647                         if (!sg_supported)
 648                                 return uas_isnt_supported(udev);
 649                         return usb_set_interface(udev,
 650                                                 alt->desc.bInterfaceNumber,
 651                                                 alt->desc.bAlternateSetting);
 652                 }
 653         }
 654
 655         return -ENODEV;
 656 }
 657
 658 static void uas_configure_endpoints(struct uas_dev_info *devinfo)
 659 {
 660         struct usb_host_endpoint *eps[4] = { };
 661         struct usb_interface *intf = devinfo->intf;
 662         struct usb_device *udev = devinfo->udev;
 663         struct usb_host_endpoint *endpoint = intf->cur_altsetting->endpoint;
 664         unsigned i, n_endpoints = intf->cur_altsetting->desc.bNumEndpoints;
 665
 666         devinfo->uas_sense_old = 0;
 667         devinfo->cmnd = NULL;
 668
 669         for (i = 0; i < n_endpoints; i++) {
 670                 unsigned char *extra = endpoint[i].extra;
 671                 int len = endpoint[i].extralen;
 672                 while (len > 1) {
 673                         if (extra[1] == USB_DT_PIPE_USAGE) {
 674                                 unsigned pipe_id = extra[2];
 675                                 if (pipe_id > 0 && pipe_id < 5)
 676                                         eps[pipe_id - 1] = &endpoint[i];
 677                                 break;
 678                         }
 679                         len -= extra[0];
 680                         extra += extra[0];
 681                 }
 682         }
 683
 684         /*
 685          * Assume that if we didn't find a control pipe descriptor, we're
 686          * using a device with old firmware that happens to be set up like
 687          * this.
 688          */
 689         if (!eps[0]) {
 690                 devinfo->cmd_pipe = usb_sndbulkpipe(udev, 1);
 691                 devinfo->status_pipe = usb_rcvbulkpipe(udev, 1);
 692                 devinfo->data_in_pipe = usb_rcvbulkpipe(udev, 2);
 693                 devinfo->data_out_pipe = usb_sndbulkpipe(udev, 2);
 694
 695                 eps[1] = usb_pipe_endpoint(udev, devinfo->status_pipe);
 696                 eps[2] = usb_pipe_endpoint(udev, devinfo->data_in_pipe);
 697                 eps[3] = usb_pipe_endpoint(udev, devinfo->data_out_pipe);
 698         } else {
 699                 devinfo->cmd_pipe = usb_sndbulkpipe(udev,
 700                                                 eps[0]->desc.bEndpointAddress);
 701                 devinfo->status_pipe = usb_rcvbulkpipe(udev,
 702                                                 eps[1]->desc.bEndpointAddress);
 703                 devinfo->data_in_pipe = usb_rcvbulkpipe(udev,
 704                                                 eps[2]->desc.bEndpointAddress);
 705                 devinfo->data_out_pipe = usb_sndbulkpipe(udev,
 706                                                 eps[3]->desc.bEndpointAddress);
 707         }
 708
 709         devinfo->qdepth = usb_alloc_streams(devinfo->intf, eps + 1, 3, 256,
 710                                                                 GFP_KERNEL);
 711         if (devinfo->qdepth < 0) {
 712                 devinfo->qdepth = 256;
 713                 devinfo->use_streams = 0;
 714         } else {
 715                 devinfo->use_streams = 1;
 716         }
 717 }
 718
 719 static int uas_alloc_status_urb(struct uas_dev_info *devinfo,
 720                 struct Scsi_Host *shost)
 721 {
 722         if (devinfo->use_streams) {
 723                 devinfo->status_urb = NULL;
 724                 return 0;
 725         }
 726
 727         devinfo->status_urb = uas_alloc_sense_urb(devinfo, GFP_KERNEL,
 728                         shost, 0);
 729         if (!devinfo->status_urb)
 730                 goto err_s_urb;
 731
 732         if (usb_submit_urb(devinfo->status_urb, GFP_KERNEL))
 733                 goto err_submit_urb;
 734
 735         return 0;
 736 err_submit_urb:
 737         usb_free_urb(devinfo->status_urb);
 738 err_s_urb:
 739         return -ENOMEM;
 740 }
 741
 742 static void uas_free_streams(struct uas_dev_info *devinfo)
 743 {
 744         struct usb_device *udev = devinfo->udev;
 745         struct usb_host_endpoint *eps[3];
 746
 747         eps[0] = usb_pipe_endpoint(udev, devinfo->status_pipe);
 748         eps[1] = usb_pipe_endpoint(udev, devinfo->data_in_pipe);
 749         eps[2] = usb_pipe_endpoint(udev, devinfo->data_out_pipe);
 750         usb_free_streams(devinfo->intf, eps, 3, GFP_KERNEL);
 751 }
 752
 753 /*
 754  * XXX: What I'd like to do here is register a SCSI host for each USB host in
 755  * the system.  Follow usb-storage's design of registering a SCSI host for
 756  * each USB device for the moment.  Can implement this by walking up the
 757  * USB hierarchy until we find a USB host.
 758  */
 759 static int uas_probe(struct usb_interface *intf, const struct usb_device_id *id)
 760 {
 761         int result;
 762         struct Scsi_Host *shost;
 763         struct uas_dev_info *devinfo;
 764         struct usb_device *udev = interface_to_usbdev(intf);
 765
 766         if (uas_switch_interface(udev, intf))
 767                 return -ENODEV;
 768
 769         devinfo = kmalloc(sizeof(struct uas_dev_info), GFP_KERNEL);
 770         if (!devinfo)
 771                 return -ENOMEM;
 772
 773         result = -ENOMEM;
 774         shost = scsi_host_alloc(&uas_host_template, sizeof(void *));
 775         if (!shost)
 776                 goto free;
 777
 778         shost->max_cmd_len = 16 + 252;
 779         shost->max_id = 1;
 780         shost->sg_tablesize = udev->bus->sg_tablesize;
 781
 782         devinfo->intf = intf;
 783         devinfo->udev = udev;
 784         uas_configure_endpoints(devinfo);
 785
 786         result = scsi_init_shared_tag_map(shost, devinfo->qdepth - 2);
 787         if (result)
 788                 goto free;
 789
 790         result = scsi_add_host(shost, &intf->dev);
 791         if (result)
 792                 goto deconfig_eps;
 793
 794         shost->hostdata[0] = (unsigned long)devinfo;
 795
 796         result = uas_alloc_status_urb(devinfo, shost);
 797         if (result)
 798                 goto err_alloc_status;
 799
 800         scsi_scan_host(shost);
 801         usb_set_intfdata(intf, shost);
 802         return result;
 803
 804 err_alloc_status:
 805         scsi_remove_host(shost);
 806         shost = NULL;
 807 deconfig_eps:
 808         uas_free_streams(devinfo);
 809  free:
 810         kfree(devinfo);
 811         if (shost)
 812                 scsi_host_put(shost);
 813         return result;
 814 }
 815
 816 static int uas_pre_reset(struct usb_interface *intf)
 817 {
 818 /* XXX: Need to return 1 if it's not our device in error handling */
 819         return 0;
 820 }
 821
 822 static int uas_post_reset(struct usb_interface *intf)
 823 {
 824 /* XXX: Need to return 1 if it's not our device in error handling */
 825         return 0;
 826 }
 827
 828 static void uas_disconnect(struct usb_interface *intf)
 829 {
 830         struct Scsi_Host *shost = usb_get_intfdata(intf);
 831         struct uas_dev_info *devinfo = (void *)shost->hostdata[0];
 832
 833         scsi_remove_host(shost);
 834         usb_kill_urb(devinfo->status_urb);
 835         usb_free_urb(devinfo->status_urb);
 836         uas_free_streams(devinfo);
 837         kfree(devinfo);
 838 }
 839
 840 /*
 841  * XXX: Should this plug into libusual so we can auto-upgrade devices from
 842  * Bulk-Only to UAS?
 843  */
 844 static struct usb_driver uas_driver = {
 845         .name = "uas",
 846         .probe = uas_probe,
 847         .disconnect = uas_disconnect,
 848         .pre_reset = uas_pre_reset,
 849         .post_reset = uas_post_reset,
 850         .id_table = uas_usb_ids,
 851 };
 852
 853 static int uas_init(void)
 854 {
 855         return usb_register(&uas_driver);
 856 }
 857
 858 static void uas_exit(void)
 859 {
 860         usb_deregister(&uas_driver);
 861 }
 862
 863 module_init(uas_init);
 864 module_exit(uas_exit);
 865
 866 MODULE_LICENSE("GPL");
 867 MODULE_AUTHOR("Matthew Wilcox and Sarah Sharp");