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         struct usb_host_endpoint *bulk_in_ep;
  77
  78         /*
  79          * Set the INQUIRY transfer length to 36.  We don't use any of
  80          * the extra data and many devices choke if asked for more or
  81          * less than 36 bytes.
  82          */
  83         sdev->inquiry_len = 36;
  84
  85         /* Scatter-gather buffers (all but the last) must have a length
  86          * divisible by the bulk maxpacket size.  Otherwise a data packet
  87          * would end up being short, causing a premature end to the data
  88          * transfer.  We'll use the maxpacket value of the bulk-IN pipe
  89          * to set the SCSI device queue's DMA alignment mask.
  90          */
  91         bulk_in_ep = us->pusb_dev->ep_in[usb_pipeendpoint(us->recv_bulk_pipe)];
  92         blk_queue_update_dma_alignment(sdev->request_queue,
  93                         le16_to_cpu(bulk_in_ep->desc.wMaxPacketSize) - 1);
  94                         /* wMaxPacketSize must be a power of 2 */
  95
  96         /*
  97          * The UFI spec treates the Peripheral Qualifier bits in an
  98          * INQUIRY result as reserved and requires devices to set them
  99          * to 0.  However the SCSI spec requires these bits to be set
 100          * to 3 to indicate when a LUN is not present.
 101          *
 102          * Let the scanning code know if this target merely sets
 103          * Peripheral Device Type to 0x1f to indicate no LUN.
 104          */
 105         if (us->subclass == US_SC_UFI)
 106                 sdev->sdev_target->pdt_1f_for_no_lun = 1;
 107
 108         return 0;
 109 }
 110
 111 static int slave_configure(struct scsi_device *sdev)
 112 {
 113         struct us_data *us = host_to_us(sdev->host);
 114
 115         /* Many devices have trouble transfering more than 32KB at a time,
 116          * while others have trouble with more than 64K. At this time we
 117          * are limiting both to 32K (64 sectores).
 118          */
 119         if (us->flags & (US_FL_MAX_SECTORS_64 | US_FL_MAX_SECTORS_MIN)) {
 120                 unsigned int max_sectors = 64;
 121
 122                 if (us->flags & US_FL_MAX_SECTORS_MIN)
 123                         max_sectors = PAGE_CACHE_SIZE >> 9;
 124                 if (sdev->request_queue->max_sectors > max_sectors)
 125                         blk_queue_max_sectors(sdev->request_queue,
 126                                               max_sectors);
 127         }
 128
 129         /* We can't put these settings in slave_alloc() because that gets
 130          * called before the device type is known.  Consequently these
 131          * settings can't be overridden via the scsi devinfo mechanism. */
 132         if (sdev->type == TYPE_DISK) {
 133
 134                 /* Disk-type devices use MODE SENSE(6) if the protocol
 135                  * (SubClass) is Transparent SCSI, otherwise they use
 136                  * MODE SENSE(10). */
 137                 if (us->subclass != US_SC_SCSI && us->subclass != US_SC_CYP_ATACB)
 138                         sdev->use_10_for_ms = 1;
 139
 140                 /* Many disks only accept MODE SENSE transfer lengths of
 141                  * 192 bytes (that's what Windows uses). */
 142                 sdev->use_192_bytes_for_3f = 1;
 143
 144                 /* Some devices don't like MODE SENSE with page=0x3f,
 145                  * which is the command used for checking if a device
 146                  * is write-protected.  Now that we tell the sd driver
 147                  * to do a 192-byte transfer with this command the
 148                  * majority of devices work fine, but a few still can't
 149                  * handle it.  The sd driver will simply assume those
 150                  * devices are write-enabled. */
 151                 if (us->flags & US_FL_NO_WP_DETECT)
 152                         sdev->skip_ms_page_3f = 1;
 153
 154                 /* A number of devices have problems with MODE SENSE for
 155                  * page x08, so we will skip it. */
 156                 sdev->skip_ms_page_8 = 1;
 157
 158                 /* Some disks return the total number of blocks in response
 159                  * to READ CAPACITY rather than the highest block number.
 160                  * If this device makes that mistake, tell the sd driver. */
 161                 if (us->flags & US_FL_FIX_CAPACITY)
 162                         sdev->fix_capacity = 1;
 163
 164                 /* A few disks have two indistinguishable version, one of
 165                  * which reports the correct capacity and the other does not.
 166                  * The sd driver has to guess which is the case. */
 167                 if (us->flags & US_FL_CAPACITY_HEURISTICS)
 168                         sdev->guess_capacity = 1;
 169
 170                 /* Some devices report a SCSI revision level above 2 but are
 171                  * unable to handle the REPORT LUNS command (for which
 172                  * support is mandatory at level 3).  Since we already have
 173                  * a Get-Max-LUN request, we won't lose much by setting the
 174                  * revision level down to 2.  The only devices that would be
 175                  * affected are those with sparse LUNs. */
 176                 if (sdev->scsi_level > SCSI_2)
 177                         sdev->sdev_target->scsi_level =
 178                                         sdev->scsi_level = SCSI_2;
 179
 180                 /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
 181                  * Hardware Error) when any low-level error occurs,
 182                  * recoverable or not.  Setting this flag tells the SCSI
 183                  * midlayer to retry such commands, which frequently will
 184                  * succeed and fix the error.  The worst this can lead to
 185                  * is an occasional series of retries that will all fail. */
 186                 sdev->retry_hwerror = 1;
 187
 188                 /* USB disks should allow restart.  Some drives spin down
 189                  * automatically, requiring a START-STOP UNIT command. */
 190                 sdev->allow_restart = 1;
 191
 192                 /* Some USB cardreaders have trouble reading an sdcard's last
 193                  * sector in a larger then 1 sector read, since the performance
 194                  * impact is negible we set this flag for all USB disks */
 195                 sdev->last_sector_bug = 1;
 196         } else {
 197
 198                 /* Non-disk-type devices don't need to blacklist any pages
 199                  * or to force 192-byte transfer lengths for MODE SENSE.
 200                  * But they do need to use MODE SENSE(10). */
 201                 sdev->use_10_for_ms = 1;
 202         }
 203
 204         /* The CB and CBI transports have no way to pass LUN values
 205          * other than the bits in the second byte of a CDB.  But those
 206          * bits don't get set to the LUN value if the device reports
 207          * scsi_level == 0 (UNKNOWN).  Hence such devices must necessarily
 208          * be single-LUN.
 209          */
 210         if ((us->protocol == US_PR_CB || us->protocol == US_PR_CBI) &&
 211                         sdev->scsi_level == SCSI_UNKNOWN)
 212                 us->max_lun = 0;
 213
 214         /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
 215          * REMOVAL command, so suppress those commands. */
 216         if (us->flags & US_FL_NOT_LOCKABLE)
 217                 sdev->lockable = 0;
 218
 219         /* this is to satisfy the compiler, tho I don't think the
 220          * return code is ever checked anywhere. */
 221         return 0;
 222 }
 223
 224 /* queue a command */
 225 /* This is always called with scsi_lock(host) held */
 226 static int queuecommand(struct scsi_cmnd *srb,
 227                         void (*done)(struct scsi_cmnd *))
 228 {
 229         struct us_data *us = host_to_us(srb->device->host);
 230
 231         US_DEBUGP("%s called\n", __func__);
 232
 233         /* check for state-transition errors */
 234         if (us->srb != NULL) {
 235                 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n",
 236                         __func__, us->srb);
 237                 return SCSI_MLQUEUE_HOST_BUSY;
 238         }
 239
 240         /* fail the command if we are disconnecting */
 241         if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) {
 242                 US_DEBUGP("Fail command during disconnect\n");
 243                 srb->result = DID_NO_CONNECT << 16;
 244                 done(srb);
 245                 return 0;
 246         }
 247
 248         /* enqueue the command and wake up the control thread */
 249         srb->scsi_done = done;
 250         us->srb = srb;
 251         up(&(us->sema));
 252
 253         return 0;
 254 }
 255
 256 /***********************************************************************
 257  * Error handling functions
 258  ***********************************************************************/
 259
 260 /* Command timeout and abort */
 261 static int command_abort(struct scsi_cmnd *srb)
 262 {
 263         struct us_data *us = host_to_us(srb->device->host);
 264
 265         US_DEBUGP("%s called\n", __func__);
 266
 267         /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
 268          * bits are protected by the host lock. */
 269         scsi_lock(us_to_host(us));
 270
 271         /* Is this command still active? */
 272         if (us->srb != srb) {
 273                 scsi_unlock(us_to_host(us));
 274                 US_DEBUGP ("-- nothing to abort\n");
 275                 return FAILED;
 276         }
 277
 278         /* Set the TIMED_OUT bit.  Also set the ABORTING bit, but only if
 279          * a device reset isn't already in progress (to avoid interfering
 280          * with the reset).  Note that we must retain the host lock while
 281          * calling usb_stor_stop_transport(); otherwise it might interfere
 282          * with an auto-reset that begins as soon as we release the lock. */
 283         set_bit(US_FLIDX_TIMED_OUT, &us->flags);
 284         if (!test_bit(US_FLIDX_RESETTING, &us->flags)) {
 285                 set_bit(US_FLIDX_ABORTING, &us->flags);
 286                 usb_stor_stop_transport(us);
 287         }
 288         scsi_unlock(us_to_host(us));
 289
 290         /* Wait for the aborted command to finish */
 291         wait_for_completion(&us->notify);
 292         return SUCCESS;
 293 }
 294
 295 /* This invokes the transport reset mechanism to reset the state of the
 296  * device */
 297 static int device_reset(struct scsi_cmnd *srb)
 298 {
 299         struct us_data *us = host_to_us(srb->device->host);
 300         int result;
 301
 302         US_DEBUGP("%s called\n", __func__);
 303
 304         /* lock the device pointers and do the reset */
 305         mutex_lock(&(us->dev_mutex));
 306         result = us->transport_reset(us);
 307         mutex_unlock(&us->dev_mutex);
 308
 309         return result < 0 ? FAILED : SUCCESS;
 310 }
 311
 312 /* Simulate a SCSI bus reset by resetting the device's USB port. */
 313 static int bus_reset(struct scsi_cmnd *srb)
 314 {
 315         struct us_data *us = host_to_us(srb->device->host);
 316         int result;
 317
 318         US_DEBUGP("%s called\n", __func__);
 319         result = usb_stor_port_reset(us);
 320         return result < 0 ? FAILED : SUCCESS;
 321 }
 322
 323 /* Report a driver-initiated device reset to the SCSI layer.
 324  * Calling this for a SCSI-initiated reset is unnecessary but harmless.
 325  * The caller must own the SCSI host lock. */
 326 void usb_stor_report_device_reset(struct us_data *us)
 327 {
 328         int i;
 329         struct Scsi_Host *host = us_to_host(us);
 330
 331         scsi_report_device_reset(host, 0, 0);
 332         if (us->flags & US_FL_SCM_MULT_TARG) {
 333                 for (i = 1; i < host->max_id; ++i)
 334                         scsi_report_device_reset(host, 0, i);
 335         }
 336 }
 337
 338 /* Report a driver-initiated bus reset to the SCSI layer.
 339  * Calling this for a SCSI-initiated reset is unnecessary but harmless.
 340  * The caller must not own the SCSI host lock. */
 341 void usb_stor_report_bus_reset(struct us_data *us)
 342 {
 343         struct Scsi_Host *host = us_to_host(us);
 344
 345         scsi_lock(host);
 346         scsi_report_bus_reset(host, 0);
 347         scsi_unlock(host);
 348 }
 349
 350 /***********************************************************************
 351  * /proc/scsi/ functions
 352  ***********************************************************************/
 353
 354 /* we use this macro to help us write into the buffer */
 355 #undef SPRINTF
 356 #define SPRINTF(args...) \
 357         do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)
 358
 359 static int proc_info (struct Scsi_Host *host, char *buffer,
 360                 char **start, off_t offset, int length, int inout)
 361 {
 362         struct us_data *us = host_to_us(host);
 363         char *pos = buffer;
 364         const char *string;
 365
 366         /* if someone is sending us data, just throw it away */
 367         if (inout)
 368                 return length;
 369
 370         /* print the controller name */
 371         SPRINTF("   Host scsi%d: usb-storage\n", host->host_no);
 372
 373         /* print product, vendor, and serial number strings */
 374         if (us->pusb_dev->manufacturer)
 375                 string = us->pusb_dev->manufacturer;
 376         else if (us->unusual_dev->vendorName)
 377                 string = us->unusual_dev->vendorName;
 378         else
 379                 string = "Unknown";
 380         SPRINTF("       Vendor: %s\n", string);
 381         if (us->pusb_dev->product)
 382                 string = us->pusb_dev->product;
 383         else if (us->unusual_dev->productName)
 384                 string = us->unusual_dev->productName;
 385         else
 386                 string = "Unknown";
 387         SPRINTF("      Product: %s\n", string);
 388         if (us->pusb_dev->serial)
 389                 string = us->pusb_dev->serial;
 390         else
 391                 string = "None";
 392         SPRINTF("Serial Number: %s\n", string);
 393
 394         /* show the protocol and transport */
 395         SPRINTF("     Protocol: %s\n", us->protocol_name);
 396         SPRINTF("    Transport: %s\n", us->transport_name);
 397
 398         /* show the device flags */
 399         if (pos < buffer + length) {
 400                 pos += sprintf(pos, "       Quirks:");
 401
 402 #define US_FLAG(name, value) \
 403         if (us->flags & value) pos += sprintf(pos, " " #name);
 404 US_DO_ALL_FLAGS
 405 #undef US_FLAG
 406
 407                 *(pos++) = '\n';
 408         }
 409
 410         /*
 411          * Calculate start of next buffer, and return value.
 412          */
 413         *start = buffer + offset;
 414
 415         if ((pos - buffer) < offset)
 416                 return (0);
 417         else if ((pos - buffer - offset) < length)
 418                 return (pos - buffer - offset);
 419         else
 420                 return (length);
 421 }
 422
 423 /***********************************************************************
 424  * Sysfs interface
 425  ***********************************************************************/
 426
 427 /* Output routine for the sysfs max_sectors file */
 428 static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf)
 429 {
 430         struct scsi_device *sdev = to_scsi_device(dev);
 431
 432         return sprintf(buf, "%u\n", sdev->request_queue->max_sectors);
 433 }
 434
 435 /* Input routine for the sysfs max_sectors file */
 436 static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf,
 437                 size_t count)
 438 {
 439         struct scsi_device *sdev = to_scsi_device(dev);
 440         unsigned short ms;
 441
 442         if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) {
 443                 blk_queue_max_sectors(sdev->request_queue, ms);
 444                 return strlen(buf);
 445         }
 446         return -EINVAL;
 447 }
 448
 449 static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors,
 450                 store_max_sectors);
 451
 452 static struct device_attribute *sysfs_device_attr_list[] = {
 453                 &dev_attr_max_sectors,
 454                 NULL,
 455                 };
 456
 457 /*
 458  * this defines our host template, with which we'll allocate hosts
 459  */
 460
 461 struct scsi_host_template usb_stor_host_template = {
 462         /* basic userland interface stuff */
 463         .name =                         "usb-storage",
 464         .proc_name =                    "usb-storage",
 465         .proc_info =                    proc_info,
 466         .info =                         host_info,
 467
 468         /* command interface -- queued only */
 469         .queuecommand =                 queuecommand,
 470
 471         /* error and abort handlers */
 472         .eh_abort_handler =             command_abort,
 473         .eh_device_reset_handler =      device_reset,
 474         .eh_bus_reset_handler =         bus_reset,
 475
 476         /* queue commands only, only one command per LUN */
 477         .can_queue =                    1,
 478         .cmd_per_lun =                  1,
 479
 480         /* unknown initiator id */
 481         .this_id =                      -1,
 482
 483         .slave_alloc =                  slave_alloc,
 484         .slave_configure =              slave_configure,
 485
 486         /* lots of sg segments can be handled */
 487         .sg_tablesize =                 SG_ALL,
 488
 489         /* limit the total size of a transfer to 120 KB */
 490         .max_sectors =                  240,
 491
 492         /* merge commands... this seems to help performance, but
 493          * periodically someone should test to see which setting is more
 494          * optimal.
 495          */
 496         .use_clustering =               1,
 497
 498         /* emulated HBA */
 499         .emulated =                     1,
 500
 501         /* we do our own delay after a device or bus reset */
 502         .skip_settle_delay =            1,
 503
 504         /* sysfs device attributes */
 505         .sdev_attrs =                   sysfs_device_attr_list,
 506
 507         /* module management */
 508         .module =                       THIS_MODULE
 509 };
 510
 511 /* To Report "Illegal Request: Invalid Field in CDB */
 512 unsigned char usb_stor_sense_invalidCDB[18] = {
 513         [0]     = 0x70,                     /* current error */
 514         [2]     = ILLEGAL_REQUEST,          /* Illegal Request = 0x05 */
 515         [7]     = 0x0a,                     /* additional length */
 516         [12]    = 0x24                      /* Invalid Field in CDB */
 517 };
 518