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
  51 #include <scsi/scsi.h>
  52 #include <scsi/scsi_cmnd.h>
  53 #include <scsi/scsi_devinfo.h>
  54 #include <scsi/scsi_device.h>
  55 #include <scsi/scsi_eh.h>
  56
  57 #include "usb.h"
  58 #include "scsiglue.h"
  59 #include "debug.h"
  60 #include "transport.h"
  61 #include "protocol.h"
  62
  63 /***********************************************************************
  64  * Host functions
  65  ***********************************************************************/
  66
  67 static const char* host_info(struct Scsi_Host *host)
  68 {
  69         return "SCSI emulation for USB Mass Storage devices";
  70 }
  71
  72 static int slave_alloc (struct scsi_device *sdev)
  73 {
  74         /*
  75          * Set the INQUIRY transfer length to 36.  We don't use any of
  76          * the extra data and many devices choke if asked for more or
  77          * less than 36 bytes.
  78          */
  79         sdev->inquiry_len = 36;
  80         return 0;
  81 }
  82
  83 static int slave_configure(struct scsi_device *sdev)
  84 {
  85         struct us_data *us = host_to_us(sdev->host);
  86
  87         /* Scatter-gather buffers (all but the last) must have a length
  88          * divisible by the bulk maxpacket size.  Otherwise a data packet
  89          * would end up being short, causing a premature end to the data
  90          * transfer.  Since high-speed bulk pipes have a maxpacket size
  91          * of 512, we'll use that as the scsi device queue's DMA alignment
  92          * mask.  Guaranteeing proper alignment of the first buffer will
  93          * have the desired effect because, except at the beginning and
  94          * the end, scatter-gather buffers follow page boundaries. */
  95         blk_queue_dma_alignment(sdev->request_queue, (512 - 1));
  96
  97         /* Set the SCSI level to at least 2.  We'll leave it at 3 if that's
  98          * what is originally reported.  We need this to avoid confusing
  99          * the SCSI layer with devices that report 0 or 1, but need 10-byte
 100          * commands (ala ATAPI devices behind certain bridges, or devices
 101          * which simply have broken INQUIRY data).
 102          *
 103          * NOTE: This means /dev/sg programs (ala cdrecord) will get the
 104          * actual information.  This seems to be the preference for
 105          * programs like that.
 106          *
 107          * NOTE: This also means that /proc/scsi/scsi and sysfs may report
 108          * the actual value or the modified one, depending on where the
 109          * data comes from.
 110          */
 111         if (sdev->scsi_level < SCSI_2)
 112                 sdev->scsi_level = SCSI_2;
 113
 114         /* According to the technical support people at Genesys Logic,
 115          * devices using their chips have problems transferring more than
 116          * 32 KB at a time.  In practice people have found that 64 KB
 117          * works okay and that's what Windows does.  But we'll be
 118          * conservative; people can always use the sysfs interface to
 119          * increase max_sectors. */
 120         if (le16_to_cpu(us->pusb_dev->descriptor.idVendor) == USB_VENDOR_ID_GENESYS &&
 121                         sdev->request_queue->max_sectors > 64)
 122                 blk_queue_max_sectors(sdev->request_queue, 64);
 123
 124         /* We can't put these settings in slave_alloc() because that gets
 125          * called before the device type is known.  Consequently these
 126          * settings can't be overridden via the scsi devinfo mechanism. */
 127         if (sdev->type == TYPE_DISK) {
 128
 129                 /* Disk-type devices use MODE SENSE(6) if the protocol
 130                  * (SubClass) is Transparent SCSI, otherwise they use
 131                  * MODE SENSE(10). */
 132                 if (us->subclass != US_SC_SCSI)
 133                         sdev->use_10_for_ms = 1;
 134
 135                 /* Many disks only accept MODE SENSE transfer lengths of
 136                  * 192 bytes (that's what Windows uses). */
 137                 sdev->use_192_bytes_for_3f = 1;
 138
 139                 /* Some devices don't like MODE SENSE with page=0x3f,
 140                  * which is the command used for checking if a device
 141                  * is write-protected.  Now that we tell the sd driver
 142                  * to do a 192-byte transfer with this command the
 143                  * majority of devices work fine, but a few still can't
 144                  * handle it.  The sd driver will simply assume those
 145                  * devices are write-enabled. */
 146                 if (us->flags & US_FL_NO_WP_DETECT)
 147                         sdev->skip_ms_page_3f = 1;
 148
 149                 /* A number of devices have problems with MODE SENSE for
 150                  * page x08, so we will skip it. */
 151                 sdev->skip_ms_page_8 = 1;
 152
 153                 /* Some disks return the total number of blocks in response
 154                  * to READ CAPACITY rather than the highest block number.
 155                  * If this device makes that mistake, tell the sd driver. */
 156                 if (us->flags & US_FL_FIX_CAPACITY)
 157                         sdev->fix_capacity = 1;
 158         } else {
 159
 160                 /* Non-disk-type devices don't need to blacklist any pages
 161                  * or to force 192-byte transfer lengths for MODE SENSE.
 162                  * But they do need to use MODE SENSE(10). */
 163                 sdev->use_10_for_ms = 1;
 164         }
 165
 166         /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
 167          * REMOVAL command, so suppress those commands. */
 168         if (us->flags & US_FL_NOT_LOCKABLE)
 169                 sdev->lockable = 0;
 170
 171         /* this is to satisfy the compiler, tho I don't think the
 172          * return code is ever checked anywhere. */
 173         return 0;
 174 }
 175
 176 /* queue a command */
 177 /* This is always called with scsi_lock(host) held */
 178 static int queuecommand(struct scsi_cmnd *srb,
 179                         void (*done)(struct scsi_cmnd *))
 180 {
 181         struct us_data *us = host_to_us(srb->device->host);
 182
 183         US_DEBUGP("%s called\n", __FUNCTION__);
 184
 185         /* check for state-transition errors */
 186         if (us->srb != NULL) {
 187                 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n",
 188                         __FUNCTION__, us->srb);
 189                 return SCSI_MLQUEUE_HOST_BUSY;
 190         }
 191
 192         /* fail the command if we are disconnecting */
 193         if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) {
 194                 US_DEBUGP("Fail command during disconnect\n");
 195                 srb->result = DID_NO_CONNECT << 16;
 196                 done(srb);
 197                 return 0;
 198         }
 199
 200         /* enqueue the command and wake up the control thread */
 201         srb->scsi_done = done;
 202         us->srb = srb;
 203         up(&(us->sema));
 204
 205         return 0;
 206 }
 207
 208 /***********************************************************************
 209  * Error handling functions
 210  ***********************************************************************/
 211
 212 /* Command timeout and abort */
 213 /* This is always called with scsi_lock(host) held */
 214 static int command_abort(struct scsi_cmnd *srb)
 215 {
 216         struct us_data *us = host_to_us(srb->device->host);
 217
 218         US_DEBUGP("%s called\n", __FUNCTION__);
 219
 220         /* Is this command still active? */
 221         if (us->srb != srb) {
 222                 US_DEBUGP ("-- nothing to abort\n");
 223                 return FAILED;
 224         }
 225
 226         /* Set the TIMED_OUT bit.  Also set the ABORTING bit, but only if
 227          * a device reset isn't already in progress (to avoid interfering
 228          * with the reset).  To prevent races with auto-reset, we must
 229          * stop any ongoing USB transfers while still holding the host
 230          * lock. */
 231         set_bit(US_FLIDX_TIMED_OUT, &us->flags);
 232         if (!test_bit(US_FLIDX_RESETTING, &us->flags)) {
 233                 set_bit(US_FLIDX_ABORTING, &us->flags);
 234                 usb_stor_stop_transport(us);
 235         }
 236         scsi_unlock(us_to_host(us));
 237
 238         /* Wait for the aborted command to finish */
 239         wait_for_completion(&us->notify);
 240
 241         /* Reacquire the lock and allow USB transfers to resume */
 242         scsi_lock(us_to_host(us));
 243         clear_bit(US_FLIDX_ABORTING, &us->flags);
 244         clear_bit(US_FLIDX_TIMED_OUT, &us->flags);
 245         return SUCCESS;
 246 }
 247
 248 /* This invokes the transport reset mechanism to reset the state of the
 249  * device */
 250 /* This is always called with scsi_lock(host) held */
 251 static int device_reset(struct scsi_cmnd *srb)
 252 {
 253         struct us_data *us = host_to_us(srb->device->host);
 254         int result;
 255
 256         US_DEBUGP("%s called\n", __FUNCTION__);
 257
 258         scsi_unlock(us_to_host(us));
 259
 260         /* lock the device pointers and do the reset */
 261         down(&(us->dev_semaphore));
 262         if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) {
 263                 result = FAILED;
 264                 US_DEBUGP("No reset during disconnect\n");
 265         } else
 266                 result = us->transport_reset(us);
 267         up(&(us->dev_semaphore));
 268
 269         /* lock the host for the return */
 270         scsi_lock(us_to_host(us));
 271         return result;
 272 }
 273
 274 /* This resets the device's USB port. */
 275 /* It refuses to work if there's more than one interface in
 276  * the device, so that other users are not affected. */
 277 /* This is always called with scsi_lock(host) held */
 278 static int bus_reset(struct scsi_cmnd *srb)
 279 {
 280         struct us_data *us = host_to_us(srb->device->host);
 281         int result, rc;
 282
 283         US_DEBUGP("%s called\n", __FUNCTION__);
 284
 285         scsi_unlock(us_to_host(us));
 286
 287         /* The USB subsystem doesn't handle synchronisation between
 288          * a device's several drivers. Therefore we reset only devices
 289          * with just one interface, which we of course own. */
 290
 291         down(&(us->dev_semaphore));
 292         if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) {
 293                 result = -EIO;
 294                 US_DEBUGP("No reset during disconnect\n");
 295         } else if (us->pusb_dev->actconfig->desc.bNumInterfaces != 1) {
 296                 result = -EBUSY;
 297                 US_DEBUGP("Refusing to reset a multi-interface device\n");
 298         } else {
 299                 rc = usb_lock_device_for_reset(us->pusb_dev, us->pusb_intf);
 300                 if (rc < 0) {
 301                         US_DEBUGP("unable to lock device for reset: %d\n", rc);
 302                         result = rc;
 303                 } else {
 304                         result = usb_reset_device(us->pusb_dev);
 305                         if (rc)
 306                                 usb_unlock_device(us->pusb_dev);
 307                         US_DEBUGP("usb_reset_device returns %d\n", result);
 308                 }
 309         }
 310         up(&(us->dev_semaphore));
 311
 312         /* lock the host for the return */
 313         scsi_lock(us_to_host(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 /***********************************************************************
 333  * /proc/scsi/ functions
 334  ***********************************************************************/
 335
 336 /* we use this macro to help us write into the buffer */
 337 #undef SPRINTF
 338 #define SPRINTF(args...) \
 339         do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)
 340
 341 static int proc_info (struct Scsi_Host *host, char *buffer,
 342                 char **start, off_t offset, int length, int inout)
 343 {
 344         struct us_data *us = host_to_us(host);
 345         char *pos = buffer;
 346         const char *string;
 347
 348         /* if someone is sending us data, just throw it away */
 349         if (inout)
 350                 return length;
 351
 352         /* print the controller name */
 353         SPRINTF("   Host scsi%d: usb-storage\n", host->host_no);
 354
 355         /* print product, vendor, and serial number strings */
 356         if (us->pusb_dev->manufacturer)
 357                 string = us->pusb_dev->manufacturer;
 358         else if (us->unusual_dev->vendorName)
 359                 string = us->unusual_dev->vendorName;
 360         else
 361                 string = "Unknown";
 362         SPRINTF("       Vendor: %s\n", string);
 363         if (us->pusb_dev->product)
 364                 string = us->pusb_dev->product;
 365         else if (us->unusual_dev->productName)
 366                 string = us->unusual_dev->productName;
 367         else
 368                 string = "Unknown";
 369         SPRINTF("      Product: %s\n", string);
 370         if (us->pusb_dev->serial)
 371                 string = us->pusb_dev->serial;
 372         else
 373                 string = "None";
 374         SPRINTF("Serial Number: %s\n", string);
 375
 376         /* show the protocol and transport */
 377         SPRINTF("     Protocol: %s\n", us->protocol_name);
 378         SPRINTF("    Transport: %s\n", us->transport_name);
 379
 380         /* show the device flags */
 381         if (pos < buffer + length) {
 382                 pos += sprintf(pos, "       Quirks:");
 383
 384 #define US_FLAG(name, value) \
 385         if (us->flags & value) pos += sprintf(pos, " " #name);
 386 US_DO_ALL_FLAGS
 387 #undef US_FLAG
 388
 389                 *(pos++) = '\n';
 390         }
 391
 392         /*
 393          * Calculate start of next buffer, and return value.
 394          */
 395         *start = buffer + offset;
 396
 397         if ((pos - buffer) < offset)
 398                 return (0);
 399         else if ((pos - buffer - offset) < length)
 400                 return (pos - buffer - offset);
 401         else
 402                 return (length);
 403 }
 404
 405 /***********************************************************************
 406  * Sysfs interface
 407  ***********************************************************************/
 408
 409 /* Output routine for the sysfs max_sectors file */
 410 static ssize_t show_max_sectors(struct device *dev, char *buf)
 411 {
 412         struct scsi_device *sdev = to_scsi_device(dev);
 413
 414         return sprintf(buf, "%u\n", sdev->request_queue->max_sectors);
 415 }
 416
 417 /* Input routine for the sysfs max_sectors file */
 418 static ssize_t store_max_sectors(struct device *dev, const char *buf,
 419                 size_t count)
 420 {
 421         struct scsi_device *sdev = to_scsi_device(dev);
 422         unsigned short ms;
 423
 424         if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) {
 425                 blk_queue_max_sectors(sdev->request_queue, ms);
 426                 return strlen(buf);
 427         }
 428         return -EINVAL;
 429 }
 430
 431 static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors,
 432                 store_max_sectors);
 433
 434 static struct device_attribute *sysfs_device_attr_list[] = {
 435                 &dev_attr_max_sectors,
 436                 NULL,
 437                 };
 438
 439 /*
 440  * this defines our host template, with which we'll allocate hosts
 441  */
 442
 443 struct scsi_host_template usb_stor_host_template = {
 444         /* basic userland interface stuff */
 445         .name =                         "usb-storage",
 446         .proc_name =                    "usb-storage",
 447         .proc_info =                    proc_info,
 448         .info =                         host_info,
 449
 450         /* command interface -- queued only */
 451         .queuecommand =                 queuecommand,
 452
 453         /* error and abort handlers */
 454         .eh_abort_handler =             command_abort,
 455         .eh_device_reset_handler =      device_reset,
 456         .eh_bus_reset_handler =         bus_reset,
 457
 458         /* queue commands only, only one command per LUN */
 459         .can_queue =                    1,
 460         .cmd_per_lun =                  1,
 461
 462         /* unknown initiator id */
 463         .this_id =                      -1,
 464
 465         .slave_alloc =                  slave_alloc,
 466         .slave_configure =              slave_configure,
 467
 468         /* lots of sg segments can be handled */
 469         .sg_tablesize =                 SG_ALL,
 470
 471         /* limit the total size of a transfer to 120 KB */
 472         .max_sectors =                  240,
 473
 474         /* merge commands... this seems to help performance, but
 475          * periodically someone should test to see which setting is more
 476          * optimal.
 477          */
 478         .use_clustering =               1,
 479
 480         /* emulated HBA */
 481         .emulated =                     1,
 482
 483         /* we do our own delay after a device or bus reset */
 484         .skip_settle_delay =            1,
 485
 486         /* sysfs device attributes */
 487         .sdev_attrs =                   sysfs_device_attr_list,
 488
 489         /* module management */
 490         .module =                       THIS_MODULE
 491 };
 492
 493 /* To Report "Illegal Request: Invalid Field in CDB */
 494 unsigned char usb_stor_sense_invalidCDB[18] = {
 495         [0]     = 0x70,                     /* current error */
 496         [2]     = ILLEGAL_REQUEST,          /* Illegal Request = 0x05 */
 497         [7]     = 0x0a,                     /* additional length */
 498         [12]    = 0x24                      /* Invalid Field in CDB */
 499 };
 500