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