drivers/usb/storage/scsiglue.c

   1 /* Driver for USB Mass Storage compliant devices
   2  * SCSI layer glue code
   3  *
   4  * Current development and maintenance by:
   5  *   (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
   6  *
   7  * Developed with the assistance of:
   8  *   (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
   9  *   (c) 2000 Stephen J. Gowdy (SGowdy@lbl.gov)
  10  *
  11  * Initial work by:
  12  *   (c) 1999 Michael Gee (michael@linuxspecific.com)
  13  *
  14  * This driver is based on the 'USB Mass Storage Class' document. This
  15  * describes in detail the protocol used to communicate with such
  16  * devices.  Clearly, the designers had SCSI and ATAPI commands in
  17  * mind when they created this document.  The commands are all very
  18  * similar to commands in the SCSI-II and ATAPI specifications.
  19  *
  20  * It is important to note that in a number of cases this class
  21  * exhibits class-specific exemptions from the USB specification.
  22  * Notably the usage of NAK, STALL and ACK differs from the norm, in
  23  * that they are used to communicate wait, failed and OK on commands.
  24  *
  25  * Also, for certain devices, the interrupt endpoint is used to convey
  26  * status of a command.
  27  *
  28  * Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
  29  * information about this driver.
  30  *
  31  * This program is free software; you can redistribute it and/or modify it
  32  * under the terms of the GNU General Public License as published by the
  33  * Free Software Foundation; either version 2, or (at your option) any
  34  * later version.
  35  *
  36  * This program is distributed in the hope that it will be useful, but
  37  * WITHOUT ANY WARRANTY; without even the implied warranty of
  38  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  39  * General Public License for more details.
  40  *
  41  * You should have received a copy of the GNU General Public License along
  42  * with this program; if not, write to the Free Software Foundation, Inc.,
  43  * 675 Mass Ave, Cambridge, MA 02139, USA.
  44  */
  45
  46 #include <linux/slab.h>
  47 #include <linux/module.h>
  48 #include <linux/mutex.h>
  49
  50 #include <scsi/scsi.h>
  51 #include <scsi/scsi_cmnd.h>
  52 #include <scsi/scsi_devinfo.h>
  53 #include <scsi/scsi_device.h>
  54 #include <scsi/scsi_eh.h>
  55
  56 #include "usb.h"
  57 #include "scsiglue.h"
  58 #include "debug.h"
  59 #include "transport.h"
  60 #include "protocol.h"
  61
  62 /***********************************************************************
  63  * Host functions
  64  ***********************************************************************/
  65
  66 static const char* host_info(struct Scsi_Host *host)
  67 {
  68         return "SCSI emulation for USB Mass Storage devices";
  69 }
  70
  71 static int slave_alloc (struct scsi_device *sdev)
  72 {
  73         struct us_data *us = host_to_us(sdev->host);
  74
  75         /*
  76          * Set the INQUIRY transfer length to 36.  We don't use any of
  77          * the extra data and many devices choke if asked for more or
  78          * less than 36 bytes.
  79          */
  80         sdev->inquiry_len = 36;
  81
  82         /* USB has unusual DMA-alignment requirements: Although the
  83          * starting address of each scatter-gather element doesn't matter,
  84          * the length of each element except the last must be divisible
  85          * by the Bulk maxpacket value.  There's currently no way to
  86          * express this by block-layer constraints, so we'll cop out
  87          * and simply require addresses to be aligned at 512-byte
  88          * boundaries.  This is okay since most block I/O involves
  89          * hardware sectors that are multiples of 512 bytes in length,
  90          * and since host controllers up through USB 2.0 have maxpacket
  91          * values no larger than 512.
  92          *
  93          * But it doesn't suffice for Wireless USB, where Bulk maxpacket
  94          * values can be as large as 2048.  To make that work properly
  95          * will require changes to the block layer.
  96          */
  97         blk_queue_update_dma_alignment(sdev->request_queue, (512 - 1));
  98
  99         /*
 100          * The UFI spec treates the Peripheral Qualifier bits in an
 101          * INQUIRY result as reserved and requires devices to set them
 102          * to 0.  However the SCSI spec requires these bits to be set
 103          * to 3 to indicate when a LUN is not present.
 104          *
 105          * Let the scanning code know if this target merely sets
 106          * Peripheral Device Type to 0x1f to indicate no LUN.
 107          */
 108         if (us->subclass == US_SC_UFI)
 109                 sdev->sdev_target->pdt_1f_for_no_lun = 1;
 110
 111         return 0;
 112 }
 113
 114 static int slave_configure(struct scsi_device *sdev)
 115 {
 116         struct us_data *us = host_to_us(sdev->host);
 117
 118         /* Many devices have trouble transfering more than 32KB at a time,
 119          * while others have trouble with more than 64K. At this time we
 120          * are limiting both to 32K (64 sectores).
 121          */
 122         if (us->fflags & (US_FL_MAX_SECTORS_64 | US_FL_MAX_SECTORS_MIN)) {
 123                 unsigned int max_sectors = 64;
 124
 125                 if (us->fflags & US_FL_MAX_SECTORS_MIN)
 126                         max_sectors = PAGE_CACHE_SIZE >> 9;
 127                 if (sdev->request_queue->max_sectors > max_sectors)
 128                         blk_queue_max_sectors(sdev->request_queue,
 129                                               max_sectors);
 130         }
 131
 132         /* We can't put these settings in slave_alloc() because that gets
 133          * called before the device type is known.  Consequently these
 134          * settings can't be overridden via the scsi devinfo mechanism. */
 135         if (sdev->type == TYPE_DISK) {
 136
 137                 /* Disk-type devices use MODE SENSE(6) if the protocol
 138                  * (SubClass) is Transparent SCSI, otherwise they use
 139                  * MODE SENSE(10). */
 140                 if (us->subclass != US_SC_SCSI && us->subclass != US_SC_CYP_ATACB)
 141                         sdev->use_10_for_ms = 1;
 142
 143                 /* Many disks only accept MODE SENSE transfer lengths of
 144                  * 192 bytes (that's what Windows uses). */
 145                 sdev->use_192_bytes_for_3f = 1;
 146
 147                 /* Some devices don't like MODE SENSE with page=0x3f,
 148                  * which is the command used for checking if a device
 149                  * is write-protected.  Now that we tell the sd driver
 150                  * to do a 192-byte transfer with this command the
 151                  * majority of devices work fine, but a few still can't
 152                  * handle it.  The sd driver will simply assume those
 153                  * devices are write-enabled. */
 154                 if (us->fflags & US_FL_NO_WP_DETECT)
 155                         sdev->skip_ms_page_3f = 1;
 156
 157                 /* A number of devices have problems with MODE SENSE for
 158                  * page x08, so we will skip it. */
 159                 sdev->skip_ms_page_8 = 1;
 160
 161                 /* Some disks return the total number of blocks in response
 162                  * to READ CAPACITY rather than the highest block number.
 163                  * If this device makes that mistake, tell the sd driver. */
 164                 if (us->fflags & US_FL_FIX_CAPACITY)
 165                         sdev->fix_capacity = 1;
 166
 167                 /* A few disks have two indistinguishable version, one of
 168                  * which reports the correct capacity and the other does not.
 169                  * The sd driver has to guess which is the case. */
 170                 if (us->fflags & US_FL_CAPACITY_HEURISTICS)
 171                         sdev->guess_capacity = 1;
 172
 173                 /* Some devices report a SCSI revision level above 2 but are
 174                  * unable to handle the REPORT LUNS command (for which
 175                  * support is mandatory at level 3).  Since we already have
 176                  * a Get-Max-LUN request, we won't lose much by setting the
 177                  * revision level down to 2.  The only devices that would be
 178                  * affected are those with sparse LUNs. */
 179                 if (sdev->scsi_level > SCSI_2)
 180                         sdev->sdev_target->scsi_level =
 181                                         sdev->scsi_level = SCSI_2;
 182
 183                 /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
 184                  * Hardware Error) when any low-level error occurs,
 185                  * recoverable or not.  Setting this flag tells the SCSI
 186                  * midlayer to retry such commands, which frequently will
 187                  * succeed and fix the error.  The worst this can lead to
 188                  * is an occasional series of retries that will all fail. */
 189                 sdev->retry_hwerror = 1;
 190
 191                 /* USB disks should allow restart.  Some drives spin down
 192                  * automatically, requiring a START-STOP UNIT command. */
 193                 sdev->allow_restart = 1;
 194
 195                 /* Some USB cardreaders have trouble reading an sdcard's last
 196                  * sector in a larger then 1 sector read, since the performance
 197                  * impact is negible we set this flag for all USB disks */
 198                 sdev->last_sector_bug = 1;
 199         } else {
 200
 201                 /* Non-disk-type devices don't need to blacklist any pages
 202                  * or to force 192-byte transfer lengths for MODE SENSE.
 203                  * But they do need to use MODE SENSE(10). */
 204                 sdev->use_10_for_ms = 1;
 205         }
 206
 207         /* The CB and CBI transports have no way to pass LUN values
 208          * other than the bits in the second byte of a CDB.  But those
 209          * bits don't get set to the LUN value if the device reports
 210          * scsi_level == 0 (UNKNOWN).  Hence such devices must necessarily
 211          * be single-LUN.
 212          */
 213         if ((us->protocol == US_PR_CB || us->protocol == US_PR_CBI) &&
 214                         sdev->scsi_level == SCSI_UNKNOWN)
 215                 us->max_lun = 0;
 216
 217         /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
 218          * REMOVAL command, so suppress those commands. */
 219         if (us->fflags & US_FL_NOT_LOCKABLE)
 220                 sdev->lockable = 0;
 221
 222         /* this is to satisfy the compiler, tho I don't think the
 223          * return code is ever checked anywhere. */
 224         return 0;
 225 }
 226
 227 /* queue a command */
 228 /* This is always called with scsi_lock(host) held */
 229 static int queuecommand(struct scsi_cmnd *srb,
 230                         void (*done)(struct scsi_cmnd *))
 231 {
 232         struct us_data *us = host_to_us(srb->device->host);
 233
 234         US_DEBUGP("%s called\n", __func__);
 235
 236         /* check for state-transition errors */
 237         if (us->srb != NULL) {
 238                 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n",
 239                         __func__, us->srb);
 240                 return SCSI_MLQUEUE_HOST_BUSY;
 241         }
 242
 243         /* fail the command if we are disconnecting */
 244         if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
 245                 US_DEBUGP("Fail command during disconnect\n");
 246                 srb->result = DID_NO_CONNECT << 16;
 247                 done(srb);
 248                 return 0;
 249         }
 250
 251         /* enqueue the command and wake up the control thread */
 252         srb->scsi_done = done;
 253         us->srb = srb;
 254         complete(&us->cmnd_ready);
 255
 256         return 0;
 257 }
 258
 259 /***********************************************************************
 260  * Error handling functions
 261  ***********************************************************************/
 262
 263 /* Command timeout and abort */
 264 static int command_abort(struct scsi_cmnd *srb)
 265 {
 266         struct us_data *us = host_to_us(srb->device->host);
 267
 268         US_DEBUGP("%s called\n", __func__);
 269
 270         /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
 271          * bits are protected by the host lock. */
 272         scsi_lock(us_to_host(us));
 273
 274         /* Is this command still active? */
 275         if (us->srb != srb) {
 276                 scsi_unlock(us_to_host(us));
 277                 US_DEBUGP ("-- nothing to abort\n");
 278                 return FAILED;
 279         }
 280
 281         /* Set the TIMED_OUT bit.  Also set the ABORTING bit, but only if
 282          * a device reset isn't already in progress (to avoid interfering
 283          * with the reset).  Note that we must retain the host lock while
 284          * calling usb_stor_stop_transport(); otherwise it might interfere
 285          * with an auto-reset that begins as soon as we release the lock. */
 286         set_bit(US_FLIDX_TIMED_OUT, &us->dflags);
 287         if (!test_bit(US_FLIDX_RESETTING, &us->dflags)) {
 288                 set_bit(US_FLIDX_ABORTING, &us->dflags);
 289                 usb_stor_stop_transport(us);
 290         }
 291         scsi_unlock(us_to_host(us));
 292
 293         /* Wait for the aborted command to finish */
 294         wait_for_completion(&us->notify);
 295         return SUCCESS;
 296 }
 297
 298 /* This invokes the transport reset mechanism to reset the state of the
 299  * device */
 300 static int device_reset(struct scsi_cmnd *srb)
 301 {
 302         struct us_data *us = host_to_us(srb->device->host);
 303         int result;
 304
 305         US_DEBUGP("%s called\n", __func__);
 306
 307         /* lock the device pointers and do the reset */
 308         mutex_lock(&(us->dev_mutex));
 309         result = us->transport_reset(us);
 310         mutex_unlock(&us->dev_mutex);
 311
 312         return result < 0 ? FAILED : SUCCESS;
 313 }
 314
 315 /* Simulate a SCSI bus reset by resetting the device's USB port. */
 316 static int bus_reset(struct scsi_cmnd *srb)
 317 {
 318         struct us_data *us = host_to_us(srb->device->host);
 319         int result;
 320
 321         US_DEBUGP("%s called\n", __func__);
 322         result = usb_stor_port_reset(us);
 323         return result < 0 ? FAILED : SUCCESS;
 324 }
 325
 326 /* Report a driver-initiated device reset to the SCSI layer.
 327  * Calling this for a SCSI-initiated reset is unnecessary but harmless.
 328  * The caller must own the SCSI host lock. */
 329 void usb_stor_report_device_reset(struct us_data *us)
 330 {
 331         int i;
 332         struct Scsi_Host *host = us_to_host(us);
 333
 334         scsi_report_device_reset(host, 0, 0);
 335         if (us->fflags & US_FL_SCM_MULT_TARG) {
 336                 for (i = 1; i < host->max_id; ++i)
 337                         scsi_report_device_reset(host, 0, i);
 338         }
 339 }
 340
 341 /* Report a driver-initiated bus reset to the SCSI layer.
 342  * Calling this for a SCSI-initiated reset is unnecessary but harmless.
 343  * The caller must not own the SCSI host lock. */
 344 void usb_stor_report_bus_reset(struct us_data *us)
 345 {
 346         struct Scsi_Host *host = us_to_host(us);
 347
 348         scsi_lock(host);
 349         scsi_report_bus_reset(host, 0);
 350         scsi_unlock(host);
 351 }
 352
 353 /***********************************************************************
 354  * /proc/scsi/ functions
 355  ***********************************************************************/
 356
 357 /* we use this macro to help us write into the buffer */
 358 #undef SPRINTF
 359 #define SPRINTF(args...) \
 360         do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)
 361
 362 static int proc_info (struct Scsi_Host *host, char *buffer,
 363                 char **start, off_t offset, int length, int inout)
 364 {
 365         struct us_data *us = host_to_us(host);
 366         char *pos = buffer;
 367         const char *string;
 368
 369         /* if someone is sending us data, just throw it away */
 370         if (inout)
 371                 return length;
 372
 373         /* print the controller name */
 374         SPRINTF("   Host scsi%d: usb-storage\n", host->host_no);
 375
 376         /* print product, vendor, and serial number strings */
 377         if (us->pusb_dev->manufacturer)
 378                 string = us->pusb_dev->manufacturer;
 379         else if (us->unusual_dev->vendorName)
 380                 string = us->unusual_dev->vendorName;
 381         else
 382                 string = "Unknown";
 383         SPRINTF("       Vendor: %s\n", string);
 384         if (us->pusb_dev->product)
 385                 string = us->pusb_dev->product;
 386         else if (us->unusual_dev->productName)
 387                 string = us->unusual_dev->productName;
 388         else
 389                 string = "Unknown";
 390         SPRINTF("      Product: %s\n", string);
 391         if (us->pusb_dev->serial)
 392                 string = us->pusb_dev->serial;
 393         else
 394                 string = "None";
 395         SPRINTF("Serial Number: %s\n", string);
 396
 397         /* show the protocol and transport */
 398         SPRINTF("     Protocol: %s\n", us->protocol_name);
 399         SPRINTF("    Transport: %s\n", us->transport_name);
 400
 401         /* show the device flags */
 402         if (pos < buffer + length) {
 403                 pos += sprintf(pos, "       Quirks:");
 404
 405 #define US_FLAG(name, value) \
 406         if (us->fflags & value) pos += sprintf(pos, " " #name);
 407 US_DO_ALL_FLAGS
 408 #undef US_FLAG
 409
 410                 *(pos++) = '\n';
 411         }
 412
 413         /*
 414          * Calculate start of next buffer, and return value.
 415          */
 416         *start = buffer + offset;
 417
 418         if ((pos - buffer) < offset)
 419                 return (0);
 420         else if ((pos - buffer - offset) < length)
 421                 return (pos - buffer - offset);
 422         else
 423                 return (length);
 424 }
 425
 426 /***********************************************************************
 427  * Sysfs interface
 428  ***********************************************************************/
 429
 430 /* Output routine for the sysfs max_sectors file */
 431 static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf)
 432 {
 433         struct scsi_device *sdev = to_scsi_device(dev);
 434
 435         return sprintf(buf, "%u\n", sdev->request_queue->max_sectors);
 436 }
 437
 438 /* Input routine for the sysfs max_sectors file */
 439 static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf,
 440                 size_t count)
 441 {
 442         struct scsi_device *sdev = to_scsi_device(dev);
 443         unsigned short ms;
 444
 445         if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) {
 446                 blk_queue_max_sectors(sdev->request_queue, ms);
 447                 return strlen(buf);
 448         }
 449         return -EINVAL;
 450 }
 451
 452 static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors,
 453                 store_max_sectors);
 454
 455 static struct device_attribute *sysfs_device_attr_list[] = {
 456                 &dev_attr_max_sectors,
 457                 NULL,
 458                 };
 459
 460 /*
 461  * this defines our host template, with which we'll allocate hosts
 462  */
 463
 464 struct scsi_host_template usb_stor_host_template = {
 465         /* basic userland interface stuff */
 466         .name =                         "usb-storage",
 467         .proc_name =                    "usb-storage",
 468         .proc_info =                    proc_info,
 469         .info =                         host_info,
 470
 471         /* command interface -- queued only */
 472         .queuecommand =                 queuecommand,
 473
 474         /* error and abort handlers */
 475         .eh_abort_handler =             command_abort,
 476         .eh_device_reset_handler =      device_reset,
 477         .eh_bus_reset_handler =         bus_reset,
 478
 479         /* queue commands only, only one command per LUN */
 480         .can_queue =                    1,
 481         .cmd_per_lun =                  1,
 482
 483         /* unknown initiator id */
 484         .this_id =                      -1,
 485
 486         .slave_alloc =                  slave_alloc,
 487         .slave_configure =              slave_configure,
 488
 489         /* lots of sg segments can be handled */
 490         .sg_tablesize =                 SG_ALL,
 491
 492         /* limit the total size of a transfer to 120 KB */
 493         .max_sectors =                  240,
 494
 495         /* merge commands... this seems to help performance, but
 496          * periodically someone should test to see which setting is more
 497          * optimal.
 498          */
 499         .use_clustering =               1,
 500
 501         /* emulated HBA */
 502         .emulated =                     1,
 503
 504         /* we do our own delay after a device or bus reset */
 505         .skip_settle_delay =            1,
 506
 507         /* sysfs device attributes */
 508         .sdev_attrs =                   sysfs_device_attr_list,
 509
 510         /* module management */
 511         .module =                       THIS_MODULE
 512 };
 513
 514 /* To Report "Illegal Request: Invalid Field in CDB */
 515 unsigned char usb_stor_sense_invalidCDB[18] = {
 516         [0]     = 0x70,                     /* current error */
 517         [2]     = ILLEGAL_REQUEST,          /* Illegal Request = 0x05 */
 518         [7]     = 0x0a,                     /* additional length */
 519         [12]    = 0x24                      /* Invalid Field in CDB */
 520 };
 521