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