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/storage.h>
  17
  18 #include <scsi/scsi.h>
  19 #include <scsi/scsi_dbg.h>
  20 #include <scsi/scsi_cmnd.h>
  21 #include <scsi/scsi_device.h>
  22 #include <scsi/scsi_host.h>
  23 #include <scsi/scsi_tcq.h>
  24
  25 /* Common header for all IUs */
  26 struct iu {
  27         __u8 iu_id;
  28         __u8 rsvd1;
  29         __be16 tag;
  30 };
  31
  32 enum {
  33         IU_ID_COMMAND           = 0x01,
  34         IU_ID_STATUS            = 0x03,
  35         IU_ID_RESPONSE          = 0x04,
  36         IU_ID_TASK_MGMT         = 0x05,
  37         IU_ID_READ_READY        = 0x06,
  38         IU_ID_WRITE_READY       = 0x07,
  39 };
  40
  41 struct command_iu {
  42         __u8 iu_id;
  43         __u8 rsvd1;
  44         __be16 tag;
  45         __u8 prio_attr;
  46         __u8 rsvd5;
  47         __u8 len;
  48         __u8 rsvd7;
  49         struct scsi_lun lun;
  50         __u8 cdb[16];   /* XXX: Overflow-checking tools may misunderstand */
  51 };
  52
  53 /*
  54  * Also used for the Read Ready and Write Ready IUs since they have the
  55  * same first four bytes
  56  */
  57 struct sense_iu {
  58         __u8 iu_id;
  59         __u8 rsvd1;
  60         __be16 tag;
  61         __be16 status_qual;
  62         __u8 status;
  63         __u8 rsvd7[7];
  64         __be16 len;
  65         __u8 sense[SCSI_SENSE_BUFFERSIZE];
  66 };
  67
  68 /*
  69  * The r00-r01c specs define this version of the SENSE IU data structure.
  70  * It's still in use by several different firmware releases.
  71  */
  72 struct sense_iu_old {
  73         __u8 iu_id;
  74         __u8 rsvd1;
  75         __be16 tag;
  76         __be16 len;
  77         __u8 status;
  78         __u8 service_response;
  79         __u8 sense[SCSI_SENSE_BUFFERSIZE];
  80 };
  81
  82 enum {
  83         CMD_PIPE_ID             = 1,
  84         STATUS_PIPE_ID          = 2,
  85         DATA_IN_PIPE_ID         = 3,
  86         DATA_OUT_PIPE_ID        = 4,
  87
  88         UAS_SIMPLE_TAG          = 0,
  89         UAS_HEAD_TAG            = 1,
  90         UAS_ORDERED_TAG         = 2,
  91         UAS_ACA                 = 4,
  92 };
  93
  94 struct uas_dev_info {
  95         struct usb_interface *intf;
  96         struct usb_device *udev;
  97         int qdepth;
  98         unsigned cmd_pipe, status_pipe, data_in_pipe, data_out_pipe;
  99         unsigned use_streams:1;
 100         unsigned uas_sense_old:1;
 101 };
 102
 103 enum {
 104         ALLOC_STATUS_URB        = (1 << 0),
 105         SUBMIT_STATUS_URB       = (1 << 1),
 106         ALLOC_DATA_IN_URB       = (1 << 2),
 107         SUBMIT_DATA_IN_URB      = (1 << 3),
 108         ALLOC_DATA_OUT_URB      = (1 << 4),
 109         SUBMIT_DATA_OUT_URB     = (1 << 5),
 110         ALLOC_CMD_URB           = (1 << 6),
 111         SUBMIT_CMD_URB          = (1 << 7),
 112 };
 113
 114 /* Overrides scsi_pointer */
 115 struct uas_cmd_info {
 116         unsigned int state;
 117         unsigned int stream;
 118         struct urb *cmd_urb;
 119         struct urb *status_urb;
 120         struct urb *data_in_urb;
 121         struct urb *data_out_urb;
 122         struct list_head list;
 123 };
 124
 125 /* I hate forward declarations, but I actually have a loop */
 126 static int uas_submit_urbs(struct scsi_cmnd *cmnd,
 127                                 struct uas_dev_info *devinfo, gfp_t gfp);
 128 static void uas_do_work(struct work_struct *work);
 129
 130 static DECLARE_WORK(uas_work, uas_do_work);
 131 static DEFINE_SPINLOCK(uas_work_lock);
 132 static LIST_HEAD(uas_work_list);
 133
 134 static void uas_do_work(struct work_struct *work)
 135 {
 136         struct uas_cmd_info *cmdinfo;
 137         struct uas_cmd_info *temp;
 138         struct list_head list;
 139         int err;
 140
 141         spin_lock_irq(&uas_work_lock);
 142         list_replace_init(&uas_work_list, &list);
 143         spin_unlock_irq(&uas_work_lock);
 144
 145         list_for_each_entry_safe(cmdinfo, temp, &list, list) {
 146                 struct scsi_pointer *scp = (void *)cmdinfo;
 147                 struct scsi_cmnd *cmnd = container_of(scp,
 148                                                         struct scsi_cmnd, SCp);
 149                 err = uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_NOIO);
 150                 if (err) {
 151                         list_del(&cmdinfo->list);
 152                         spin_lock_irq(&uas_work_lock);
 153                         list_add_tail(&cmdinfo->list, &uas_work_list);
 154                         spin_unlock_irq(&uas_work_lock);
 155                         schedule_work(&uas_work);
 156                 }
 157         }
 158 }
 159
 160 static void uas_sense(struct urb *urb, struct scsi_cmnd *cmnd)
 161 {
 162         struct sense_iu *sense_iu = urb->transfer_buffer;
 163         struct scsi_device *sdev = cmnd->device;
 164
 165         if (urb->actual_length > 16) {
 166                 unsigned len = be16_to_cpup(&sense_iu->len);
 167                 if (len + 16 != urb->actual_length) {
 168                         int newlen = min(len + 16, urb->actual_length) - 16;
 169                         if (newlen < 0)
 170                                 newlen = 0;
 171                         sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
 172                                 "disagrees with IU sense data length %d, "
 173                                 "using %d bytes of sense data\n", __func__,
 174                                         urb->actual_length, len, newlen);
 175                         len = newlen;
 176                 }
 177                 memcpy(cmnd->sense_buffer, sense_iu->sense, len);
 178         }
 179
 180         cmnd->result = sense_iu->status;
 181         if (sdev->current_cmnd)
 182                 sdev->current_cmnd = NULL;
 183         cmnd->scsi_done(cmnd);
 184         usb_free_urb(urb);
 185 }
 186
 187 static void uas_sense_old(struct urb *urb, struct scsi_cmnd *cmnd)
 188 {
 189         struct sense_iu_old *sense_iu = urb->transfer_buffer;
 190         struct scsi_device *sdev = cmnd->device;
 191
 192         if (urb->actual_length > 8) {
 193                 unsigned len = be16_to_cpup(&sense_iu->len) - 2;
 194                 if (len + 8 != urb->actual_length) {
 195                         int newlen = min(len + 8, urb->actual_length) - 8;
 196                         if (newlen < 0)
 197                                 newlen = 0;
 198                         sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
 199                                 "disagrees with IU sense data length %d, "
 200                                 "using %d bytes of sense data\n", __func__,
 201                                         urb->actual_length, len, newlen);
 202                         len = newlen;
 203                 }
 204                 memcpy(cmnd->sense_buffer, sense_iu->sense, len);
 205         }
 206
 207         cmnd->result = sense_iu->status;
 208         if (sdev->current_cmnd)
 209                 sdev->current_cmnd = NULL;
 210         cmnd->scsi_done(cmnd);
 211         usb_free_urb(urb);
 212 }
 213
 214 static void uas_xfer_data(struct urb *urb, struct scsi_cmnd *cmnd,
 215                                                         unsigned direction)
 216 {
 217         struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
 218         int err;
 219
 220         cmdinfo->state = direction | SUBMIT_STATUS_URB;
 221         err = uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_ATOMIC);
 222         if (err) {
 223                 spin_lock(&uas_work_lock);
 224                 list_add_tail(&cmdinfo->list, &uas_work_list);
 225                 spin_unlock(&uas_work_lock);
 226                 schedule_work(&uas_work);
 227         }
 228 }
 229
 230 static void uas_stat_cmplt(struct urb *urb)
 231 {
 232         struct iu *iu = urb->transfer_buffer;
 233         struct scsi_device *sdev = urb->context;
 234         struct uas_dev_info *devinfo = sdev->hostdata;
 235         struct scsi_cmnd *cmnd;
 236         u16 tag;
 237
 238         if (urb->status) {
 239                 dev_err(&urb->dev->dev, "URB BAD STATUS %d\n", urb->status);
 240                 usb_free_urb(urb);
 241                 return;
 242         }
 243
 244         tag = be16_to_cpup(&iu->tag) - 1;
 245         if (sdev->current_cmnd)
 246                 cmnd = sdev->current_cmnd;
 247         else
 248                 cmnd = scsi_find_tag(sdev, tag);
 249         if (!cmnd) {
 250                 usb_free_urb(urb);
 251                 return;
 252         }
 253
 254         switch (iu->iu_id) {
 255         case IU_ID_STATUS:
 256                 if (urb->actual_length < 16)
 257                         devinfo->uas_sense_old = 1;
 258                 if (devinfo->uas_sense_old)
 259                         uas_sense_old(urb, cmnd);
 260                 else
 261                         uas_sense(urb, cmnd);
 262                 break;
 263         case IU_ID_READ_READY:
 264                 uas_xfer_data(urb, cmnd, SUBMIT_DATA_IN_URB);
 265                 break;
 266         case IU_ID_WRITE_READY:
 267                 uas_xfer_data(urb, cmnd, SUBMIT_DATA_OUT_URB);
 268                 break;
 269         default:
 270                 scmd_printk(KERN_ERR, cmnd,
 271                         "Bogus IU (%d) received on status pipe\n", iu->iu_id);
 272         }
 273 }
 274
 275 static void uas_data_cmplt(struct urb *urb)
 276 {
 277         struct scsi_data_buffer *sdb = urb->context;
 278         sdb->resid = sdb->length - urb->actual_length;
 279         usb_free_urb(urb);
 280 }
 281
 282 static struct urb *uas_alloc_data_urb(struct uas_dev_info *devinfo, gfp_t gfp,
 283                                 unsigned int pipe, u16 stream_id,
 284                                 struct scsi_data_buffer *sdb,
 285                                 enum dma_data_direction dir)
 286 {
 287         struct usb_device *udev = devinfo->udev;
 288         struct urb *urb = usb_alloc_urb(0, gfp);
 289
 290         if (!urb)
 291                 goto out;
 292         usb_fill_bulk_urb(urb, udev, pipe, NULL, sdb->length, uas_data_cmplt,
 293                                                                         sdb);
 294         if (devinfo->use_streams)
 295                 urb->stream_id = stream_id;
 296         urb->num_sgs = udev->bus->sg_tablesize ? sdb->table.nents : 0;
 297         urb->sg = sdb->table.sgl;
 298  out:
 299         return urb;
 300 }
 301
 302 static struct urb *uas_alloc_sense_urb(struct uas_dev_info *devinfo, gfp_t gfp,
 303                                         struct scsi_cmnd *cmnd, u16 stream_id)
 304 {
 305         struct usb_device *udev = devinfo->udev;
 306         struct urb *urb = usb_alloc_urb(0, gfp);
 307         struct sense_iu *iu;
 308
 309         if (!urb)
 310                 goto out;
 311
 312         iu = kzalloc(sizeof(*iu), gfp);
 313         if (!iu)
 314                 goto free;
 315
 316         usb_fill_bulk_urb(urb, udev, devinfo->status_pipe, iu, sizeof(*iu),
 317                                                 uas_stat_cmplt, cmnd->device);
 318         urb->stream_id = stream_id;
 319         urb->transfer_flags |= URB_FREE_BUFFER;
 320  out:
 321         return urb;
 322  free:
 323         usb_free_urb(urb);
 324         return NULL;
 325 }
 326
 327 static struct urb *uas_alloc_cmd_urb(struct uas_dev_info *devinfo, gfp_t gfp,
 328                                         struct scsi_cmnd *cmnd, u16 stream_id)
 329 {
 330         struct usb_device *udev = devinfo->udev;
 331         struct scsi_device *sdev = cmnd->device;
 332         struct urb *urb = usb_alloc_urb(0, gfp);
 333         struct command_iu *iu;
 334         int len;
 335
 336         if (!urb)
 337                 goto out;
 338
 339         len = cmnd->cmd_len - 16;
 340         if (len < 0)
 341                 len = 0;
 342         len = ALIGN(len, 4);
 343         iu = kzalloc(sizeof(*iu) + len, gfp);
 344         if (!iu)
 345                 goto free;
 346
 347         iu->iu_id = IU_ID_COMMAND;
 348         if (blk_rq_tagged(cmnd->request))
 349                 iu->tag = cpu_to_be16(cmnd->request->tag + 1);
 350         else
 351                 iu->tag = cpu_to_be16(1);
 352         iu->prio_attr = UAS_SIMPLE_TAG;
 353         iu->len = len;
 354         int_to_scsilun(sdev->lun, &iu->lun);
 355         memcpy(iu->cdb, cmnd->cmnd, cmnd->cmd_len);
 356
 357         usb_fill_bulk_urb(urb, udev, devinfo->cmd_pipe, iu, sizeof(*iu) + len,
 358                                                         usb_free_urb, NULL);
 359         urb->transfer_flags |= URB_FREE_BUFFER;
 360  out:
 361         return urb;
 362  free:
 363         usb_free_urb(urb);
 364         return NULL;
 365 }
 366
 367 /*
 368  * Why should I request the Status IU before sending the Command IU?  Spec
 369  * says to, but also says the device may receive them in any order.  Seems
 370  * daft to me.
 371  */
 372
 373 static int uas_submit_urbs(struct scsi_cmnd *cmnd,
 374                                         struct uas_dev_info *devinfo, gfp_t gfp)
 375 {
 376         struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
 377
 378         if (cmdinfo->state & ALLOC_STATUS_URB) {
 379                 cmdinfo->status_urb = uas_alloc_sense_urb(devinfo, gfp, cmnd,
 380                                                           cmdinfo->stream);
 381                 if (!cmdinfo->status_urb)
 382                         return SCSI_MLQUEUE_DEVICE_BUSY;
 383                 cmdinfo->state &= ~ALLOC_STATUS_URB;
 384         }
 385
 386         if (cmdinfo->state & SUBMIT_STATUS_URB) {
 387                 if (usb_submit_urb(cmdinfo->status_urb, gfp)) {
 388                         scmd_printk(KERN_INFO, cmnd,
 389                                         "sense urb submission failure\n");
 390                         return SCSI_MLQUEUE_DEVICE_BUSY;
 391                 }
 392                 cmdinfo->state &= ~SUBMIT_STATUS_URB;
 393         }
 394
 395         if (cmdinfo->state & ALLOC_DATA_IN_URB) {
 396                 cmdinfo->data_in_urb = uas_alloc_data_urb(devinfo, gfp,
 397                                         devinfo->data_in_pipe, cmdinfo->stream,
 398                                         scsi_in(cmnd), DMA_FROM_DEVICE);
 399                 if (!cmdinfo->data_in_urb)
 400                         return SCSI_MLQUEUE_DEVICE_BUSY;
 401                 cmdinfo->state &= ~ALLOC_DATA_IN_URB;
 402         }
 403
 404         if (cmdinfo->state & SUBMIT_DATA_IN_URB) {
 405                 if (usb_submit_urb(cmdinfo->data_in_urb, gfp)) {
 406                         scmd_printk(KERN_INFO, cmnd,
 407                                         "data in urb submission failure\n");
 408                         return SCSI_MLQUEUE_DEVICE_BUSY;
 409                 }
 410                 cmdinfo->state &= ~SUBMIT_DATA_IN_URB;
 411         }
 412
 413         if (cmdinfo->state & ALLOC_DATA_OUT_URB) {
 414                 cmdinfo->data_out_urb = uas_alloc_data_urb(devinfo, gfp,
 415                                         devinfo->data_out_pipe, cmdinfo->stream,
 416                                         scsi_out(cmnd), DMA_TO_DEVICE);
 417                 if (!cmdinfo->data_out_urb)
 418                         return SCSI_MLQUEUE_DEVICE_BUSY;
 419                 cmdinfo->state &= ~ALLOC_DATA_OUT_URB;
 420         }
 421
 422         if (cmdinfo->state & SUBMIT_DATA_OUT_URB) {
 423                 if (usb_submit_urb(cmdinfo->data_out_urb, gfp)) {
 424                         scmd_printk(KERN_INFO, cmnd,
 425                                         "data out urb submission failure\n");
 426                         return SCSI_MLQUEUE_DEVICE_BUSY;
 427                 }
 428                 cmdinfo->state &= ~SUBMIT_DATA_OUT_URB;
 429         }
 430
 431         if (cmdinfo->state & ALLOC_CMD_URB) {
 432                 cmdinfo->cmd_urb = uas_alloc_cmd_urb(devinfo, gfp, cmnd,
 433                                                         cmdinfo->stream);
 434                 if (!cmdinfo->cmd_urb)
 435                         return SCSI_MLQUEUE_DEVICE_BUSY;
 436                 cmdinfo->state &= ~ALLOC_CMD_URB;
 437         }
 438
 439         if (cmdinfo->state & SUBMIT_CMD_URB) {
 440                 if (usb_submit_urb(cmdinfo->cmd_urb, gfp)) {
 441                         scmd_printk(KERN_INFO, cmnd,
 442                                         "cmd urb submission failure\n");
 443                         return SCSI_MLQUEUE_DEVICE_BUSY;
 444                 }
 445                 cmdinfo->state &= ~SUBMIT_CMD_URB;
 446         }
 447
 448         return 0;
 449 }
 450
 451 static int uas_queuecommand_lck(struct scsi_cmnd *cmnd,
 452                                         void (*done)(struct scsi_cmnd *))
 453 {
 454         struct scsi_device *sdev = cmnd->device;
 455         struct uas_dev_info *devinfo = sdev->hostdata;
 456         struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
 457         int err;
 458
 459         BUILD_BUG_ON(sizeof(struct uas_cmd_info) > sizeof(struct scsi_pointer));
 460
 461         if (!cmdinfo->status_urb && sdev->current_cmnd)
 462                 return SCSI_MLQUEUE_DEVICE_BUSY;
 463
 464         if (blk_rq_tagged(cmnd->request)) {
 465                 cmdinfo->stream = cmnd->request->tag + 1;
 466         } else {
 467                 sdev->current_cmnd = cmnd;
 468                 cmdinfo->stream = 1;
 469         }
 470
 471         cmnd->scsi_done = done;
 472
 473         cmdinfo->state = ALLOC_STATUS_URB | SUBMIT_STATUS_URB |
 474                         ALLOC_CMD_URB | SUBMIT_CMD_URB;
 475
 476         switch (cmnd->sc_data_direction) {
 477         case DMA_FROM_DEVICE:
 478                 cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
 479                 break;
 480         case DMA_BIDIRECTIONAL:
 481                 cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
 482         case DMA_TO_DEVICE:
 483                 cmdinfo->state |= ALLOC_DATA_OUT_URB | SUBMIT_DATA_OUT_URB;
 484         case DMA_NONE:
 485                 break;
 486         }
 487
 488         if (!devinfo->use_streams) {
 489                 cmdinfo->state &= ~(SUBMIT_DATA_IN_URB | SUBMIT_DATA_OUT_URB);
 490                 cmdinfo->stream = 0;
 491         }
 492
 493         err = uas_submit_urbs(cmnd, devinfo, GFP_ATOMIC);
 494         if (err) {
 495                 /* If we did nothing, give up now */
 496                 if (cmdinfo->state & SUBMIT_STATUS_URB) {
 497                         usb_free_urb(cmdinfo->status_urb);
 498                         return SCSI_MLQUEUE_DEVICE_BUSY;
 499                 }
 500                 spin_lock(&uas_work_lock);
 501                 list_add_tail(&cmdinfo->list, &uas_work_list);
 502                 spin_unlock(&uas_work_lock);
 503                 schedule_work(&uas_work);
 504         }
 505
 506         return 0;
 507 }
 508
 509 static DEF_SCSI_QCMD(uas_queuecommand)
 510
 511 static int uas_eh_abort_handler(struct scsi_cmnd *cmnd)
 512 {
 513         struct scsi_device *sdev = cmnd->device;
 514         sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
 515                                                         cmnd->request->tag);
 516
 517 /* XXX: Send ABORT TASK Task Management command */
 518         return FAILED;
 519 }
 520
 521 static int uas_eh_device_reset_handler(struct scsi_cmnd *cmnd)
 522 {
 523         struct scsi_device *sdev = cmnd->device;
 524         sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
 525                                                         cmnd->request->tag);
 526
 527 /* XXX: Send LOGICAL UNIT RESET Task Management command */
 528         return FAILED;
 529 }
 530
 531 static int uas_eh_target_reset_handler(struct scsi_cmnd *cmnd)
 532 {
 533         struct scsi_device *sdev = cmnd->device;
 534         sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
 535                                                         cmnd->request->tag);
 536
 537 /* XXX: Can we reset just the one USB interface?
 538  * Would calling usb_set_interface() have the right effect?
 539  */
 540         return FAILED;
 541 }
 542
 543 static int uas_eh_bus_reset_handler(struct scsi_cmnd *cmnd)
 544 {
 545         struct scsi_device *sdev = cmnd->device;
 546         struct uas_dev_info *devinfo = sdev->hostdata;
 547         struct usb_device *udev = devinfo->udev;
 548
 549         sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
 550                                                         cmnd->request->tag);
 551
 552         if (usb_reset_device(udev))
 553                 return SUCCESS;
 554
 555         return FAILED;
 556 }
 557
 558 static int uas_slave_alloc(struct scsi_device *sdev)
 559 {
 560         sdev->hostdata = (void *)sdev->host->hostdata[0];
 561         return 0;
 562 }
 563
 564 static int uas_slave_configure(struct scsi_device *sdev)
 565 {
 566         struct uas_dev_info *devinfo = sdev->hostdata;
 567         scsi_set_tag_type(sdev, MSG_ORDERED_TAG);
 568         scsi_activate_tcq(sdev, devinfo->qdepth - 1);
 569         return 0;
 570 }
 571
 572 static struct scsi_host_template uas_host_template = {
 573         .module = THIS_MODULE,
 574         .name = "uas",
 575         .queuecommand = uas_queuecommand,
 576         .slave_alloc = uas_slave_alloc,
 577         .slave_configure = uas_slave_configure,
 578         .eh_abort_handler = uas_eh_abort_handler,
 579         .eh_device_reset_handler = uas_eh_device_reset_handler,
 580         .eh_target_reset_handler = uas_eh_target_reset_handler,
 581         .eh_bus_reset_handler = uas_eh_bus_reset_handler,
 582         .can_queue = 65536,     /* Is there a limit on the _host_ ? */
 583         .this_id = -1,
 584         .sg_tablesize = SG_NONE,
 585         .cmd_per_lun = 1,       /* until we override it */
 586         .skip_settle_delay = 1,
 587         .ordered_tag = 1,
 588 };
 589
 590 static struct usb_device_id uas_usb_ids[] = {
 591         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_BULK) },
 592         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_UAS) },
 593         /* 0xaa is a prototype device I happen to have access to */
 594         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, 0xaa) },
 595         { }
 596 };
 597 MODULE_DEVICE_TABLE(usb, uas_usb_ids);
 598
 599 static int uas_is_interface(struct usb_host_interface *intf)
 600 {
 601         return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
 602                 intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
 603                 intf->desc.bInterfaceProtocol == USB_PR_UAS);
 604 }
 605
 606 static int uas_switch_interface(struct usb_device *udev,
 607                                                 struct usb_interface *intf)
 608 {
 609         int i;
 610
 611         if (uas_is_interface(intf->cur_altsetting))
 612                 return 0;
 613
 614         for (i = 0; i < intf->num_altsetting; i++) {
 615                 struct usb_host_interface *alt = &intf->altsetting[i];
 616                 if (alt == intf->cur_altsetting)
 617                         continue;
 618                 if (uas_is_interface(alt))
 619                         return usb_set_interface(udev,
 620                                                 alt->desc.bInterfaceNumber,
 621                                                 alt->desc.bAlternateSetting);
 622         }
 623
 624         return -ENODEV;
 625 }
 626
 627 static void uas_configure_endpoints(struct uas_dev_info *devinfo)
 628 {
 629         struct usb_host_endpoint *eps[4] = { };
 630         struct usb_interface *intf = devinfo->intf;
 631         struct usb_device *udev = devinfo->udev;
 632         struct usb_host_endpoint *endpoint = intf->cur_altsetting->endpoint;
 633         unsigned i, n_endpoints = intf->cur_altsetting->desc.bNumEndpoints;
 634
 635         devinfo->uas_sense_old = 0;
 636
 637         for (i = 0; i < n_endpoints; i++) {
 638                 unsigned char *extra = endpoint[i].extra;
 639                 int len = endpoint[i].extralen;
 640                 while (len > 1) {
 641                         if (extra[1] == USB_DT_PIPE_USAGE) {
 642                                 unsigned pipe_id = extra[2];
 643                                 if (pipe_id > 0 && pipe_id < 5)
 644                                         eps[pipe_id - 1] = &endpoint[i];
 645                                 break;
 646                         }
 647                         len -= extra[0];
 648                         extra += extra[0];
 649                 }
 650         }
 651
 652         /*
 653          * Assume that if we didn't find a control pipe descriptor, we're
 654          * using a device with old firmware that happens to be set up like
 655          * this.
 656          */
 657         if (!eps[0]) {
 658                 devinfo->cmd_pipe = usb_sndbulkpipe(udev, 1);
 659                 devinfo->status_pipe = usb_rcvbulkpipe(udev, 1);
 660                 devinfo->data_in_pipe = usb_rcvbulkpipe(udev, 2);
 661                 devinfo->data_out_pipe = usb_sndbulkpipe(udev, 2);
 662
 663                 eps[1] = usb_pipe_endpoint(udev, devinfo->status_pipe);
 664                 eps[2] = usb_pipe_endpoint(udev, devinfo->data_in_pipe);
 665                 eps[3] = usb_pipe_endpoint(udev, devinfo->data_out_pipe);
 666         } else {
 667                 devinfo->cmd_pipe = usb_sndbulkpipe(udev,
 668                                                 eps[0]->desc.bEndpointAddress);
 669                 devinfo->status_pipe = usb_rcvbulkpipe(udev,
 670                                                 eps[1]->desc.bEndpointAddress);
 671                 devinfo->data_in_pipe = usb_rcvbulkpipe(udev,
 672                                                 eps[2]->desc.bEndpointAddress);
 673                 devinfo->data_out_pipe = usb_sndbulkpipe(udev,
 674                                                 eps[3]->desc.bEndpointAddress);
 675         }
 676
 677         devinfo->qdepth = usb_alloc_streams(devinfo->intf, eps + 1, 3, 256,
 678                                                                 GFP_KERNEL);
 679         if (devinfo->qdepth < 0) {
 680                 devinfo->qdepth = 256;
 681                 devinfo->use_streams = 0;
 682         } else {
 683                 devinfo->use_streams = 1;
 684         }
 685 }
 686
 687 static void uas_free_streams(struct uas_dev_info *devinfo)
 688 {
 689         struct usb_device *udev = devinfo->udev;
 690         struct usb_host_endpoint *eps[3];
 691
 692         eps[0] = usb_pipe_endpoint(udev, devinfo->status_pipe);
 693         eps[1] = usb_pipe_endpoint(udev, devinfo->data_in_pipe);
 694         eps[2] = usb_pipe_endpoint(udev, devinfo->data_out_pipe);
 695         usb_free_streams(devinfo->intf, eps, 3, GFP_KERNEL);
 696 }
 697
 698 /*
 699  * XXX: What I'd like to do here is register a SCSI host for each USB host in
 700  * the system.  Follow usb-storage's design of registering a SCSI host for
 701  * each USB device for the moment.  Can implement this by walking up the
 702  * USB hierarchy until we find a USB host.
 703  */
 704 static int uas_probe(struct usb_interface *intf, const struct usb_device_id *id)
 705 {
 706         int result;
 707         struct Scsi_Host *shost;
 708         struct uas_dev_info *devinfo;
 709         struct usb_device *udev = interface_to_usbdev(intf);
 710
 711         if (uas_switch_interface(udev, intf))
 712                 return -ENODEV;
 713
 714         devinfo = kmalloc(sizeof(struct uas_dev_info), GFP_KERNEL);
 715         if (!devinfo)
 716                 return -ENOMEM;
 717
 718         result = -ENOMEM;
 719         shost = scsi_host_alloc(&uas_host_template, sizeof(void *));
 720         if (!shost)
 721                 goto free;
 722
 723         shost->max_cmd_len = 16 + 252;
 724         shost->max_id = 1;
 725         shost->sg_tablesize = udev->bus->sg_tablesize;
 726
 727         devinfo->intf = intf;
 728         devinfo->udev = udev;
 729         uas_configure_endpoints(devinfo);
 730
 731         result = scsi_init_shared_tag_map(shost, devinfo->qdepth - 1);
 732         if (result)
 733                 goto free;
 734
 735         result = scsi_add_host(shost, &intf->dev);
 736         if (result)
 737                 goto deconfig_eps;
 738
 739         shost->hostdata[0] = (unsigned long)devinfo;
 740
 741         scsi_scan_host(shost);
 742         usb_set_intfdata(intf, shost);
 743         return result;
 744
 745 deconfig_eps:
 746         uas_free_streams(devinfo);
 747  free:
 748         kfree(devinfo);
 749         if (shost)
 750                 scsi_host_put(shost);
 751         return result;
 752 }
 753
 754 static int uas_pre_reset(struct usb_interface *intf)
 755 {
 756 /* XXX: Need to return 1 if it's not our device in error handling */
 757         return 0;
 758 }
 759
 760 static int uas_post_reset(struct usb_interface *intf)
 761 {
 762 /* XXX: Need to return 1 if it's not our device in error handling */
 763         return 0;
 764 }
 765
 766 static void uas_disconnect(struct usb_interface *intf)
 767 {
 768         struct Scsi_Host *shost = usb_get_intfdata(intf);
 769         struct uas_dev_info *devinfo = (void *)shost->hostdata[0];
 770
 771         scsi_remove_host(shost);
 772         uas_free_streams(devinfo);
 773         kfree(devinfo);
 774 }
 775
 776 /*
 777  * XXX: Should this plug into libusual so we can auto-upgrade devices from
 778  * Bulk-Only to UAS?
 779  */
 780 static struct usb_driver uas_driver = {
 781         .name = "uas",
 782         .probe = uas_probe,
 783         .disconnect = uas_disconnect,
 784         .pre_reset = uas_pre_reset,
 785         .post_reset = uas_post_reset,
 786         .id_table = uas_usb_ids,
 787 };
 788
 789 static int uas_init(void)
 790 {
 791         return usb_register(&uas_driver);
 792 }
 793
 794 static void uas_exit(void)
 795 {
 796         usb_deregister(&uas_driver);
 797 }
 798
 799 module_init(uas_init);
 800 module_exit(uas_exit);
 801
 802 MODULE_LICENSE("GPL");
 803 MODULE_AUTHOR("Matthew Wilcox and Sarah Sharp");