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