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 = sdev->sdev_target->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
 159                 /* Some devices report a SCSI revision level above 2 but are
 160                  * unable to handle the REPORT LUNS command (for which
 161                  * support is mandatory at level 3).  Since we already have
 162                  * a Get-Max-LUN request, we won't lose much by setting the
 163                  * revision level down to 2.  The only devices that would be
 164                  * affected are those with sparse LUNs. */
 165                 sdev->scsi_level = sdev->sdev_target->scsi_level = SCSI_2;
 166
 167                 /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
 168                  * Hardware Error) when any low-level error occurs,
 169                  * recoverable or not.  Setting this flag tells the SCSI
 170                  * midlayer to retry such commands, which frequently will
 171                  * succeed and fix the error.  The worst this can lead to
 172                  * is an occasional series of retries that will all fail. */
 173                 sdev->retry_hwerror = 1;
 174
 175         } else {
 176
 177                 /* Non-disk-type devices don't need to blacklist any pages
 178                  * or to force 192-byte transfer lengths for MODE SENSE.
 179                  * But they do need to use MODE SENSE(10). */
 180                 sdev->use_10_for_ms = 1;
 181         }
 182
 183         /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
 184          * REMOVAL command, so suppress those commands. */
 185         if (us->flags & US_FL_NOT_LOCKABLE)
 186                 sdev->lockable = 0;
 187
 188         /* this is to satisfy the compiler, tho I don't think the
 189          * return code is ever checked anywhere. */
 190         return 0;
 191 }
 192
 193 /* queue a command */
 194 /* This is always called with scsi_lock(host) held */
 195 static int queuecommand(struct scsi_cmnd *srb,
 196                         void (*done)(struct scsi_cmnd *))
 197 {
 198         struct us_data *us = host_to_us(srb->device->host);
 199
 200         US_DEBUGP("%s called\n", __FUNCTION__);
 201
 202         /* check for state-transition errors */
 203         if (us->srb != NULL) {
 204                 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n",
 205                         __FUNCTION__, us->srb);
 206                 return SCSI_MLQUEUE_HOST_BUSY;
 207         }
 208
 209         /* fail the command if we are disconnecting */
 210         if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) {
 211                 US_DEBUGP("Fail command during disconnect\n");
 212                 srb->result = DID_NO_CONNECT << 16;
 213                 done(srb);
 214                 return 0;
 215         }
 216
 217         /* enqueue the command and wake up the control thread */
 218         srb->scsi_done = done;
 219         us->srb = srb;
 220         up(&(us->sema));
 221
 222         return 0;
 223 }
 224
 225 /***********************************************************************
 226  * Error handling functions
 227  ***********************************************************************/
 228
 229 /* Command timeout and abort */
 230 static int command_abort(struct scsi_cmnd *srb)
 231 {
 232         struct us_data *us = host_to_us(srb->device->host);
 233
 234         US_DEBUGP("%s called\n", __FUNCTION__);
 235
 236         /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
 237          * bits are protected by the host lock. */
 238         scsi_lock(us_to_host(us));
 239
 240         /* Is this command still active? */
 241         if (us->srb != srb) {
 242                 scsi_unlock(us_to_host(us));
 243                 US_DEBUGP ("-- nothing to abort\n");
 244                 return FAILED;
 245         }
 246
 247         /* Set the TIMED_OUT bit.  Also set the ABORTING bit, but only if
 248          * a device reset isn't already in progress (to avoid interfering
 249          * with the reset).  Note that we must retain the host lock while
 250          * calling usb_stor_stop_transport(); otherwise it might interfere
 251          * with an auto-reset that begins as soon as we release the lock. */
 252         set_bit(US_FLIDX_TIMED_OUT, &us->flags);
 253         if (!test_bit(US_FLIDX_RESETTING, &us->flags)) {
 254                 set_bit(US_FLIDX_ABORTING, &us->flags);
 255                 usb_stor_stop_transport(us);
 256         }
 257         scsi_unlock(us_to_host(us));
 258
 259         /* Wait for the aborted command to finish */
 260         wait_for_completion(&us->notify);
 261         return SUCCESS;
 262 }
 263
 264 /* This invokes the transport reset mechanism to reset the state of the
 265  * device */
 266 static int device_reset(struct scsi_cmnd *srb)
 267 {
 268         struct us_data *us = host_to_us(srb->device->host);
 269         int result;
 270
 271         US_DEBUGP("%s called\n", __FUNCTION__);
 272
 273         /* lock the device pointers and do the reset */
 274         down(&(us->dev_semaphore));
 275         result = us->transport_reset(us);
 276         up(&(us->dev_semaphore));
 277
 278         return result < 0 ? FAILED : SUCCESS;
 279 }
 280
 281 /* Simulate a SCSI bus reset by resetting the device's USB port. */
 282 static int bus_reset(struct scsi_cmnd *srb)
 283 {
 284         struct us_data *us = host_to_us(srb->device->host);
 285         int result;
 286
 287         US_DEBUGP("%s called\n", __FUNCTION__);
 288
 289         down(&(us->dev_semaphore));
 290         result = usb_stor_port_reset(us);
 291         up(&(us->dev_semaphore));
 292
 293         return result < 0 ? FAILED : SUCCESS;
 294 }
 295
 296 /* Report a driver-initiated device reset to the SCSI layer.
 297  * Calling this for a SCSI-initiated reset is unnecessary but harmless.
 298  * The caller must own the SCSI host lock. */
 299 void usb_stor_report_device_reset(struct us_data *us)
 300 {
 301         int i;
 302         struct Scsi_Host *host = us_to_host(us);
 303
 304         scsi_report_device_reset(host, 0, 0);
 305         if (us->flags & US_FL_SCM_MULT_TARG) {
 306                 for (i = 1; i < host->max_id; ++i)
 307                         scsi_report_device_reset(host, 0, i);
 308         }
 309 }
 310
 311 /* Report a driver-initiated bus reset to the SCSI layer.
 312  * Calling this for a SCSI-initiated reset is unnecessary but harmless.
 313  * The caller must own the SCSI host lock. */
 314 void usb_stor_report_bus_reset(struct us_data *us)
 315 {
 316         scsi_report_bus_reset(us_to_host(us), 0);
 317 }
 318
 319 /***********************************************************************
 320  * /proc/scsi/ functions
 321  ***********************************************************************/
 322
 323 /* we use this macro to help us write into the buffer */
 324 #undef SPRINTF
 325 #define SPRINTF(args...) \
 326         do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)
 327
 328 static int proc_info (struct Scsi_Host *host, char *buffer,
 329                 char **start, off_t offset, int length, int inout)
 330 {
 331         struct us_data *us = host_to_us(host);
 332         char *pos = buffer;
 333         const char *string;
 334
 335         /* if someone is sending us data, just throw it away */
 336         if (inout)
 337                 return length;
 338
 339         /* print the controller name */
 340         SPRINTF("   Host scsi%d: usb-storage\n", host->host_no);
 341
 342         /* print product, vendor, and serial number strings */
 343         if (us->pusb_dev->manufacturer)
 344                 string = us->pusb_dev->manufacturer;
 345         else if (us->unusual_dev->vendorName)
 346                 string = us->unusual_dev->vendorName;
 347         else
 348                 string = "Unknown";
 349         SPRINTF("       Vendor: %s\n", string);
 350         if (us->pusb_dev->product)
 351                 string = us->pusb_dev->product;
 352         else if (us->unusual_dev->productName)
 353                 string = us->unusual_dev->productName;
 354         else
 355                 string = "Unknown";
 356         SPRINTF("      Product: %s\n", string);
 357         if (us->pusb_dev->serial)
 358                 string = us->pusb_dev->serial;
 359         else
 360                 string = "None";
 361         SPRINTF("Serial Number: %s\n", string);
 362
 363         /* show the protocol and transport */
 364         SPRINTF("     Protocol: %s\n", us->protocol_name);
 365         SPRINTF("    Transport: %s\n", us->transport_name);
 366
 367         /* show the device flags */
 368         if (pos < buffer + length) {
 369                 pos += sprintf(pos, "       Quirks:");
 370
 371 #define US_FLAG(name, value) \
 372         if (us->flags & value) pos += sprintf(pos, " " #name);
 373 US_DO_ALL_FLAGS
 374 #undef US_FLAG
 375
 376                 *(pos++) = '\n';
 377         }
 378
 379         /*
 380          * Calculate start of next buffer, and return value.
 381          */
 382         *start = buffer + offset;
 383
 384         if ((pos - buffer) < offset)
 385                 return (0);
 386         else if ((pos - buffer - offset) < length)
 387                 return (pos - buffer - offset);
 388         else
 389                 return (length);
 390 }
 391
 392 /***********************************************************************
 393  * Sysfs interface
 394  ***********************************************************************/
 395
 396 /* Output routine for the sysfs max_sectors file */
 397 static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf)
 398 {
 399         struct scsi_device *sdev = to_scsi_device(dev);
 400
 401         return sprintf(buf, "%u\n", sdev->request_queue->max_sectors);
 402 }
 403
 404 /* Input routine for the sysfs max_sectors file */
 405 static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf,
 406                 size_t count)
 407 {
 408         struct scsi_device *sdev = to_scsi_device(dev);
 409         unsigned short ms;
 410
 411         if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) {
 412                 blk_queue_max_sectors(sdev->request_queue, ms);
 413                 return strlen(buf);
 414         }
 415         return -EINVAL;
 416 }
 417
 418 static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors,
 419                 store_max_sectors);
 420
 421 static struct device_attribute *sysfs_device_attr_list[] = {
 422                 &dev_attr_max_sectors,
 423                 NULL,
 424                 };
 425
 426 /*
 427  * this defines our host template, with which we'll allocate hosts
 428  */
 429
 430 struct scsi_host_template usb_stor_host_template = {
 431         /* basic userland interface stuff */
 432         .name =                         "usb-storage",
 433         .proc_name =                    "usb-storage",
 434         .proc_info =                    proc_info,
 435         .info =                         host_info,
 436
 437         /* command interface -- queued only */
 438         .queuecommand =                 queuecommand,
 439
 440         /* error and abort handlers */
 441         .eh_abort_handler =             command_abort,
 442         .eh_device_reset_handler =      device_reset,
 443         .eh_bus_reset_handler =         bus_reset,
 444
 445         /* queue commands only, only one command per LUN */
 446         .can_queue =                    1,
 447         .cmd_per_lun =                  1,
 448
 449         /* unknown initiator id */
 450         .this_id =                      -1,
 451
 452         .slave_alloc =                  slave_alloc,
 453         .slave_configure =              slave_configure,
 454
 455         /* lots of sg segments can be handled */
 456         .sg_tablesize =                 SG_ALL,
 457
 458         /* limit the total size of a transfer to 120 KB */
 459         .max_sectors =                  240,
 460
 461         /* merge commands... this seems to help performance, but
 462          * periodically someone should test to see which setting is more
 463          * optimal.
 464          */
 465         .use_clustering =               1,
 466
 467         /* emulated HBA */
 468         .emulated =                     1,
 469
 470         /* we do our own delay after a device or bus reset */
 471         .skip_settle_delay =            1,
 472
 473         /* sysfs device attributes */
 474         .sdev_attrs =                   sysfs_device_attr_list,
 475
 476         /* module management */
 477         .module =                       THIS_MODULE
 478 };
 479
 480 /* To Report "Illegal Request: Invalid Field in CDB */
 481 unsigned char usb_stor_sense_invalidCDB[18] = {
 482         [0]     = 0x70,                     /* current error */
 483         [2]     = ILLEGAL_REQUEST,          /* Illegal Request = 0x05 */
 484         [7]     = 0x0a,                     /* additional length */
 485         [12]    = 0x24                      /* Invalid Field in CDB */
 486 };
 487