drivers/usb/storage/scsiglue.c

   1 /* Driver for USB Mass Storage compliant devices
   2  * SCSI layer glue code
   3  *
   4  * $Id: scsiglue.c,v 1.26 2002/04/22 03:39:43 mdharm Exp $
   5  *
   6  * Current development and maintenance by:
   7  *   (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
   8  *
   9  * Developed with the assistance of:
  10  *   (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
  11  *   (c) 2000 Stephen J. Gowdy (SGowdy@lbl.gov)
  12  *
  13  * Initial work by:
  14  *   (c) 1999 Michael Gee (michael@linuxspecific.com)
  15  *
  16  * This driver is based on the 'USB Mass Storage Class' document. This
  17  * describes in detail the protocol used to communicate with such
  18  * devices.  Clearly, the designers had SCSI and ATAPI commands in
  19  * mind when they created this document.  The commands are all very
  20  * similar to commands in the SCSI-II and ATAPI specifications.
  21  *
  22  * It is important to note that in a number of cases this class
  23  * exhibits class-specific exemptions from the USB specification.
  24  * Notably the usage of NAK, STALL and ACK differs from the norm, in
  25  * that they are used to communicate wait, failed and OK on commands.
  26  *
  27  * Also, for certain devices, the interrupt endpoint is used to convey
  28  * status of a command.
  29  *
  30  * Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
  31  * information about this driver.
  32  *
  33  * This program is free software; you can redistribute it and/or modify it
  34  * under the terms of the GNU General Public License as published by the
  35  * Free Software Foundation; either version 2, or (at your option) any
  36  * later version.
  37  *
  38  * This program is distributed in the hope that it will be useful, but
  39  * WITHOUT ANY WARRANTY; without even the implied warranty of
  40  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  41  * General Public License for more details.
  42  *
  43  * You should have received a copy of the GNU General Public License along
  44  * with this program; if not, write to the Free Software Foundation, Inc.,
  45  * 675 Mass Ave, Cambridge, MA 02139, USA.
  46  */
  47
  48 #include <linux/slab.h>
  49 #include <linux/module.h>
  50 #include <linux/mutex.h>
  51
  52 #include <scsi/scsi.h>
  53 #include <scsi/scsi_cmnd.h>
  54 #include <scsi/scsi_devinfo.h>
  55 #include <scsi/scsi_device.h>
  56 #include <scsi/scsi_eh.h>
  57
  58 #include "usb.h"
  59 #include "scsiglue.h"
  60 #include "debug.h"
  61 #include "transport.h"
  62 #include "protocol.h"
  63
  64 /***********************************************************************
  65  * Host functions
  66  ***********************************************************************/
  67
  68 static const char* host_info(struct Scsi_Host *host)
  69 {
  70         return "SCSI emulation for USB Mass Storage devices";
  71 }
  72
  73 static int slave_alloc (struct scsi_device *sdev)
  74 {
  75         struct us_data *us = host_to_us(sdev->host);
  76
  77         /*
  78          * Set the INQUIRY transfer length to 36.  We don't use any of
  79          * the extra data and many devices choke if asked for more or
  80          * less than 36 bytes.
  81          */
  82         sdev->inquiry_len = 36;
  83
  84         /*
  85          * The UFI spec treates the Peripheral Qualifier bits in an
  86          * INQUIRY result as reserved and requires devices to set them
  87          * to 0.  However the SCSI spec requires these bits to be set
  88          * to 3 to indicate when a LUN is not present.
  89          *
  90          * Let the scanning code know if this target merely sets
  91          * Peripheral Device Type to 0x1f to indicate no LUN.
  92          */
  93         if (us->subclass == US_SC_UFI)
  94                 sdev->sdev_target->pdt_1f_for_no_lun = 1;
  95
  96         return 0;
  97 }
  98
  99 static int slave_configure(struct scsi_device *sdev)
 100 {
 101         struct us_data *us = host_to_us(sdev->host);
 102
 103         /* Scatter-gather buffers (all but the last) must have a length
 104          * divisible by the bulk maxpacket size.  Otherwise a data packet
 105          * would end up being short, causing a premature end to the data
 106          * transfer.  Since high-speed bulk pipes have a maxpacket size
 107          * of 512, we'll use that as the scsi device queue's DMA alignment
 108          * mask.  Guaranteeing proper alignment of the first buffer will
 109          * have the desired effect because, except at the beginning and
 110          * the end, scatter-gather buffers follow page boundaries. */
 111         blk_queue_dma_alignment(sdev->request_queue, (512 - 1));
 112
 113         /* Many devices have trouble transfering more than 32KB at a time,
 114          * while others have trouble with more than 64K. At this time we
 115          * are limiting both to 32K (64 sectores).
 116          */
 117         if (us->flags & (US_FL_MAX_SECTORS_64 | US_FL_MAX_SECTORS_MIN)) {
 118                 unsigned int max_sectors = 64;
 119
 120                 if (us->flags & US_FL_MAX_SECTORS_MIN)
 121                         max_sectors = PAGE_CACHE_SIZE >> 9;
 122                 if (sdev->request_queue->max_sectors > max_sectors)
 123                         blk_queue_max_sectors(sdev->request_queue,
 124                                               max_sectors);
 125         }
 126
 127         /* We can't put these settings in slave_alloc() because that gets
 128          * called before the device type is known.  Consequently these
 129          * settings can't be overridden via the scsi devinfo mechanism. */
 130         if (sdev->type == TYPE_DISK) {
 131
 132                 /* Disk-type devices use MODE SENSE(6) if the protocol
 133                  * (SubClass) is Transparent SCSI, otherwise they use
 134                  * MODE SENSE(10). */
 135                 if (us->subclass != US_SC_SCSI)
 136                         sdev->use_10_for_ms = 1;
 137
 138                 /* Many disks only accept MODE SENSE transfer lengths of
 139                  * 192 bytes (that's what Windows uses). */
 140                 sdev->use_192_bytes_for_3f = 1;
 141
 142                 /* Some devices don't like MODE SENSE with page=0x3f,
 143                  * which is the command used for checking if a device
 144                  * is write-protected.  Now that we tell the sd driver
 145                  * to do a 192-byte transfer with this command the
 146                  * majority of devices work fine, but a few still can't
 147                  * handle it.  The sd driver will simply assume those
 148                  * devices are write-enabled. */
 149                 if (us->flags & US_FL_NO_WP_DETECT)
 150                         sdev->skip_ms_page_3f = 1;
 151
 152                 /* A number of devices have problems with MODE SENSE for
 153                  * page x08, so we will skip it. */
 154                 sdev->skip_ms_page_8 = 1;
 155
 156                 /* Some disks return the total number of blocks in response
 157                  * to READ CAPACITY rather than the highest block number.
 158                  * If this device makes that mistake, tell the sd driver. */
 159                 if (us->flags & US_FL_FIX_CAPACITY)
 160                         sdev->fix_capacity = 1;
 161
 162                 /* A few disks have two indistinguishable version, one of
 163                  * which reports the correct capacity and the other does not.
 164                  * The sd driver has to guess which is the case. */
 165                 if (us->flags & US_FL_CAPACITY_HEURISTICS)
 166                         sdev->guess_capacity = 1;
 167
 168                 /* Some devices report a SCSI revision level above 2 but are
 169                  * unable to handle the REPORT LUNS command (for which
 170                  * support is mandatory at level 3).  Since we already have
 171                  * a Get-Max-LUN request, we won't lose much by setting the
 172                  * revision level down to 2.  The only devices that would be
 173                  * affected are those with sparse LUNs. */
 174                 if (sdev->scsi_level > SCSI_2)
 175                         sdev->sdev_target->scsi_level =
 176                                         sdev->scsi_level = SCSI_2;
 177
 178                 /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
 179                  * Hardware Error) when any low-level error occurs,
 180                  * recoverable or not.  Setting this flag tells the SCSI
 181                  * midlayer to retry such commands, which frequently will
 182                  * succeed and fix the error.  The worst this can lead to
 183                  * is an occasional series of retries that will all fail. */
 184                 sdev->retry_hwerror = 1;
 185
 186                 /* USB disks should allow restart.  Some drives spin down
 187                  * automatically, requiring a START-STOP UNIT command. */
 188                 sdev->allow_restart = 1;
 189
 190         } else {
 191
 192                 /* Non-disk-type devices don't need to blacklist any pages
 193                  * or to force 192-byte transfer lengths for MODE SENSE.
 194                  * But they do need to use MODE SENSE(10). */
 195                 sdev->use_10_for_ms = 1;
 196         }
 197
 198         /* The CB and CBI transports have no way to pass LUN values
 199          * other than the bits in the second byte of a CDB.  But those
 200          * bits don't get set to the LUN value if the device reports
 201          * scsi_level == 0 (UNKNOWN).  Hence such devices must necessarily
 202          * be single-LUN.
 203          */
 204         if ((us->protocol == US_PR_CB || us->protocol == US_PR_CBI) &&
 205                         sdev->scsi_level == SCSI_UNKNOWN)
 206                 us->max_lun = 0;
 207
 208         /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
 209          * REMOVAL command, so suppress those commands. */
 210         if (us->flags & US_FL_NOT_LOCKABLE)
 211                 sdev->lockable = 0;
 212
 213         /* this is to satisfy the compiler, tho I don't think the
 214          * return code is ever checked anywhere. */
 215         return 0;
 216 }
 217
 218 /* queue a command */
 219 /* This is always called with scsi_lock(host) held */
 220 static int queuecommand(struct scsi_cmnd *srb,
 221                         void (*done)(struct scsi_cmnd *))
 222 {
 223         struct us_data *us = host_to_us(srb->device->host);
 224
 225         US_DEBUGP("%s called\n", __FUNCTION__);
 226
 227         /* check for state-transition errors */
 228         if (us->srb != NULL) {
 229                 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n",
 230                         __FUNCTION__, us->srb);
 231                 return SCSI_MLQUEUE_HOST_BUSY;
 232         }
 233
 234         /* fail the command if we are disconnecting */
 235         if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) {
 236                 US_DEBUGP("Fail command during disconnect\n");
 237                 srb->result = DID_NO_CONNECT << 16;
 238                 done(srb);
 239                 return 0;
 240         }
 241
 242         /* enqueue the command and wake up the control thread */
 243         srb->scsi_done = done;
 244         us->srb = srb;
 245         up(&(us->sema));
 246
 247         return 0;
 248 }
 249
 250 /***********************************************************************
 251  * Error handling functions
 252  ***********************************************************************/
 253
 254 /* Command timeout and abort */
 255 static int command_abort(struct scsi_cmnd *srb)
 256 {
 257         struct us_data *us = host_to_us(srb->device->host);
 258
 259         US_DEBUGP("%s called\n", __FUNCTION__);
 260
 261         /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
 262          * bits are protected by the host lock. */
 263         scsi_lock(us_to_host(us));
 264
 265         /* Is this command still active? */
 266         if (us->srb != srb) {
 267                 scsi_unlock(us_to_host(us));
 268                 US_DEBUGP ("-- nothing to abort\n");
 269                 return FAILED;
 270         }
 271
 272         /* Set the TIMED_OUT bit.  Also set the ABORTING bit, but only if
 273          * a device reset isn't already in progress (to avoid interfering
 274          * with the reset).  Note that we must retain the host lock while
 275          * calling usb_stor_stop_transport(); otherwise it might interfere
 276          * with an auto-reset that begins as soon as we release the lock. */
 277         set_bit(US_FLIDX_TIMED_OUT, &us->flags);
 278         if (!test_bit(US_FLIDX_RESETTING, &us->flags)) {
 279                 set_bit(US_FLIDX_ABORTING, &us->flags);
 280                 usb_stor_stop_transport(us);
 281         }
 282         scsi_unlock(us_to_host(us));
 283
 284         /* Wait for the aborted command to finish */
 285         wait_for_completion(&us->notify);
 286         return SUCCESS;
 287 }
 288
 289 /* This invokes the transport reset mechanism to reset the state of the
 290  * device */
 291 static int device_reset(struct scsi_cmnd *srb)
 292 {
 293         struct us_data *us = host_to_us(srb->device->host);
 294         int result;
 295
 296         US_DEBUGP("%s called\n", __FUNCTION__);
 297
 298         /* lock the device pointers and do the reset */
 299         mutex_lock(&(us->dev_mutex));
 300         result = us->transport_reset(us);
 301         mutex_unlock(&us->dev_mutex);
 302
 303         return result < 0 ? FAILED : SUCCESS;
 304 }
 305
 306 /* Simulate a SCSI bus reset by resetting the device's USB port. */
 307 static int bus_reset(struct scsi_cmnd *srb)
 308 {
 309         struct us_data *us = host_to_us(srb->device->host);
 310         int result;
 311
 312         US_DEBUGP("%s called\n", __FUNCTION__);
 313         result = usb_stor_port_reset(us);
 314         return result < 0 ? FAILED : SUCCESS;
 315 }
 316
 317 /* Report a driver-initiated device reset to the SCSI layer.
 318  * Calling this for a SCSI-initiated reset is unnecessary but harmless.
 319  * The caller must own the SCSI host lock. */
 320 void usb_stor_report_device_reset(struct us_data *us)
 321 {
 322         int i;
 323         struct Scsi_Host *host = us_to_host(us);
 324
 325         scsi_report_device_reset(host, 0, 0);
 326         if (us->flags & US_FL_SCM_MULT_TARG) {
 327                 for (i = 1; i < host->max_id; ++i)
 328                         scsi_report_device_reset(host, 0, i);
 329         }
 330 }
 331
 332 /* Report a driver-initiated bus reset to the SCSI layer.
 333  * Calling this for a SCSI-initiated reset is unnecessary but harmless.
 334  * The caller must not own the SCSI host lock. */
 335 void usb_stor_report_bus_reset(struct us_data *us)
 336 {
 337         struct Scsi_Host *host = us_to_host(us);
 338
 339         scsi_lock(host);
 340         scsi_report_bus_reset(host, 0);
 341         scsi_unlock(host);
 342 }
 343
 344 /***********************************************************************
 345  * /proc/scsi/ functions
 346  ***********************************************************************/
 347
 348 /* we use this macro to help us write into the buffer */
 349 #undef SPRINTF
 350 #define SPRINTF(args...) \
 351         do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)
 352
 353 static int proc_info (struct Scsi_Host *host, char *buffer,
 354                 char **start, off_t offset, int length, int inout)
 355 {
 356         struct us_data *us = host_to_us(host);
 357         char *pos = buffer;
 358         const char *string;
 359
 360         /* if someone is sending us data, just throw it away */
 361         if (inout)
 362                 return length;
 363
 364         /* print the controller name */
 365         SPRINTF("   Host scsi%d: usb-storage\n", host->host_no);
 366
 367         /* print product, vendor, and serial number strings */
 368         if (us->pusb_dev->manufacturer)
 369                 string = us->pusb_dev->manufacturer;
 370         else if (us->unusual_dev->vendorName)
 371                 string = us->unusual_dev->vendorName;
 372         else
 373                 string = "Unknown";
 374         SPRINTF("       Vendor: %s\n", string);
 375         if (us->pusb_dev->product)
 376                 string = us->pusb_dev->product;
 377         else if (us->unusual_dev->productName)
 378                 string = us->unusual_dev->productName;
 379         else
 380                 string = "Unknown";
 381         SPRINTF("      Product: %s\n", string);
 382         if (us->pusb_dev->serial)
 383                 string = us->pusb_dev->serial;
 384         else
 385                 string = "None";
 386         SPRINTF("Serial Number: %s\n", string);
 387
 388         /* show the protocol and transport */
 389         SPRINTF("     Protocol: %s\n", us->protocol_name);
 390         SPRINTF("    Transport: %s\n", us->transport_name);
 391
 392         /* show the device flags */
 393         if (pos < buffer + length) {
 394                 pos += sprintf(pos, "       Quirks:");
 395
 396 #define US_FLAG(name, value) \
 397         if (us->flags & value) pos += sprintf(pos, " " #name);
 398 US_DO_ALL_FLAGS
 399 #undef US_FLAG
 400
 401                 *(pos++) = '\n';
 402         }
 403
 404         /*
 405          * Calculate start of next buffer, and return value.
 406          */
 407         *start = buffer + offset;
 408
 409         if ((pos - buffer) < offset)
 410                 return (0);
 411         else if ((pos - buffer - offset) < length)
 412                 return (pos - buffer - offset);
 413         else
 414                 return (length);
 415 }
 416
 417 /***********************************************************************
 418  * Sysfs interface
 419  ***********************************************************************/
 420
 421 /* Output routine for the sysfs max_sectors file */
 422 static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf)
 423 {
 424         struct scsi_device *sdev = to_scsi_device(dev);
 425
 426         return sprintf(buf, "%u\n", sdev->request_queue->max_sectors);
 427 }
 428
 429 /* Input routine for the sysfs max_sectors file */
 430 static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf,
 431                 size_t count)
 432 {
 433         struct scsi_device *sdev = to_scsi_device(dev);
 434         unsigned short ms;
 435
 436         if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) {
 437                 blk_queue_max_sectors(sdev->request_queue, ms);
 438                 return strlen(buf);
 439         }
 440         return -EINVAL;
 441 }
 442
 443 static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors,
 444                 store_max_sectors);
 445
 446 static struct device_attribute *sysfs_device_attr_list[] = {
 447                 &dev_attr_max_sectors,
 448                 NULL,
 449                 };
 450
 451 /*
 452  * this defines our host template, with which we'll allocate hosts
 453  */
 454
 455 struct scsi_host_template usb_stor_host_template = {
 456         /* basic userland interface stuff */
 457         .name =                         "usb-storage",
 458         .proc_name =                    "usb-storage",
 459         .proc_info =                    proc_info,
 460         .info =                         host_info,
 461
 462         /* command interface -- queued only */
 463         .queuecommand =                 queuecommand,
 464
 465         /* error and abort handlers */
 466         .eh_abort_handler =             command_abort,
 467         .eh_device_reset_handler =      device_reset,
 468         .eh_bus_reset_handler =         bus_reset,
 469
 470         /* queue commands only, only one command per LUN */
 471         .can_queue =                    1,
 472         .cmd_per_lun =                  1,
 473
 474         /* unknown initiator id */
 475         .this_id =                      -1,
 476
 477         .slave_alloc =                  slave_alloc,
 478         .slave_configure =              slave_configure,
 479
 480         /* lots of sg segments can be handled */
 481         .sg_tablesize =                 SG_ALL,
 482
 483         /* limit the total size of a transfer to 120 KB */
 484         .max_sectors =                  240,
 485
 486         /* merge commands... this seems to help performance, but
 487          * periodically someone should test to see which setting is more
 488          * optimal.
 489          */
 490         .use_clustering =               1,
 491
 492         /* emulated HBA */
 493         .emulated =                     1,
 494
 495         /* we do our own delay after a device or bus reset */
 496         .skip_settle_delay =            1,
 497
 498         /* sysfs device attributes */
 499         .sdev_attrs =                   sysfs_device_attr_list,
 500
 501         /* module management */
 502         .module =                       THIS_MODULE
 503 };
 504
 505 /* To Report "Illegal Request: Invalid Field in CDB */
 506 unsigned char usb_stor_sense_invalidCDB[18] = {
 507         [0]     = 0x70,                     /* current error */
 508         [2]     = ILLEGAL_REQUEST,          /* Illegal Request = 0x05 */
 509         [7]     = 0x0a,                     /* additional length */
 510         [12]    = 0x24                      /* Invalid Field in CDB */
 511 };
 512