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 /* Scatter-gather buffers (all but the last) must have a length 85 * divisible by the bulk maxpacket size. Otherwise a data packet 86 * would end up being short, causing a premature end to the data 87 * transfer. Since high-speed bulk pipes have a maxpacket size 88 * of 512, we'll use that as the scsi device queue's DMA alignment 89 * mask. Guaranteeing proper alignment of the first buffer will 90 * have the desired effect because, except at the beginning and 91 * the end, scatter-gather buffers follow page boundaries. */ 92 blk_queue_update_dma_alignment(sdev->request_queue, (512 - 1)); 93 94 /* 95 * The UFI spec treates the Peripheral Qualifier bits in an 96 * INQUIRY result as reserved and requires devices to set them 97 * to 0. However the SCSI spec requires these bits to be set 98 * to 3 to indicate when a LUN is not present. 99 * 100 * Let the scanning code know if this target merely sets 101 * Peripheral Device Type to 0x1f to indicate no LUN. 102 */ 103 if (us->subclass == US_SC_UFI) 104 sdev->sdev_target->pdt_1f_for_no_lun = 1; 105 106 return 0; 107 } 108 109 static int slave_configure(struct scsi_device *sdev) 110 { 111 struct us_data *us = host_to_us(sdev->host); 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 /* Some USB cardreaders have trouble reading an sdcard's last 191 * sector in a larger then 1 sector read, since the performance 192 * impact is negible we set this flag for all USB disks */ 193 sdev->last_sector_bug = 1; 194 } else { 195 196 /* Non-disk-type devices don't need to blacklist any pages 197 * or to force 192-byte transfer lengths for MODE SENSE. 198 * But they do need to use MODE SENSE(10). */ 199 sdev->use_10_for_ms = 1; 200 } 201 202 /* The CB and CBI transports have no way to pass LUN values 203 * other than the bits in the second byte of a CDB. But those 204 * bits don't get set to the LUN value if the device reports 205 * scsi_level == 0 (UNKNOWN). Hence such devices must necessarily 206 * be single-LUN. 207 */ 208 if ((us->protocol == US_PR_CB || us->protocol == US_PR_CBI) && 209 sdev->scsi_level == SCSI_UNKNOWN) 210 us->max_lun = 0; 211 212 /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM 213 * REMOVAL command, so suppress those commands. */ 214 if (us->flags & US_FL_NOT_LOCKABLE) 215 sdev->lockable = 0; 216 217 /* this is to satisfy the compiler, tho I don't think the 218 * return code is ever checked anywhere. */ 219 return 0; 220 } 221 222 /* queue a command */ 223 /* This is always called with scsi_lock(host) held */ 224 static int queuecommand(struct scsi_cmnd *srb, 225 void (*done)(struct scsi_cmnd *)) 226 { 227 struct us_data *us = host_to_us(srb->device->host); 228 229 US_DEBUGP("%s called\n", __FUNCTION__); 230 231 /* check for state-transition errors */ 232 if (us->srb != NULL) { 233 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n", 234 __FUNCTION__, us->srb); 235 return SCSI_MLQUEUE_HOST_BUSY; 236 } 237 238 /* fail the command if we are disconnecting */ 239 if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) { 240 US_DEBUGP("Fail command during disconnect\n"); 241 srb->result = DID_NO_CONNECT << 16; 242 done(srb); 243 return 0; 244 } 245 246 /* enqueue the command and wake up the control thread */ 247 srb->scsi_done = done; 248 us->srb = srb; 249 up(&(us->sema)); 250 251 return 0; 252 } 253 254 /*********************************************************************** 255 * Error handling functions 256 ***********************************************************************/ 257 258 /* Command timeout and abort */ 259 static int command_abort(struct scsi_cmnd *srb) 260 { 261 struct us_data *us = host_to_us(srb->device->host); 262 263 US_DEBUGP("%s called\n", __FUNCTION__); 264 265 /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING 266 * bits are protected by the host lock. */ 267 scsi_lock(us_to_host(us)); 268 269 /* Is this command still active? */ 270 if (us->srb != srb) { 271 scsi_unlock(us_to_host(us)); 272 US_DEBUGP ("-- nothing to abort\n"); 273 return FAILED; 274 } 275 276 /* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if 277 * a device reset isn't already in progress (to avoid interfering 278 * with the reset). Note that we must retain the host lock while 279 * calling usb_stor_stop_transport(); otherwise it might interfere 280 * with an auto-reset that begins as soon as we release the lock. */ 281 set_bit(US_FLIDX_TIMED_OUT, &us->flags); 282 if (!test_bit(US_FLIDX_RESETTING, &us->flags)) { 283 set_bit(US_FLIDX_ABORTING, &us->flags); 284 usb_stor_stop_transport(us); 285 } 286 scsi_unlock(us_to_host(us)); 287 288 /* Wait for the aborted command to finish */ 289 wait_for_completion(&us->notify); 290 return SUCCESS; 291 } 292 293 /* This invokes the transport reset mechanism to reset the state of the 294 * device */ 295 static int device_reset(struct scsi_cmnd *srb) 296 { 297 struct us_data *us = host_to_us(srb->device->host); 298 int result; 299 300 US_DEBUGP("%s called\n", __FUNCTION__); 301 302 /* lock the device pointers and do the reset */ 303 mutex_lock(&(us->dev_mutex)); 304 result = us->transport_reset(us); 305 mutex_unlock(&us->dev_mutex); 306 307 return result < 0 ? FAILED : SUCCESS; 308 } 309 310 /* Simulate a SCSI bus reset by resetting the device's USB port. */ 311 static int bus_reset(struct scsi_cmnd *srb) 312 { 313 struct us_data *us = host_to_us(srb->device->host); 314 int result; 315 316 US_DEBUGP("%s called\n", __FUNCTION__); 317 result = usb_stor_port_reset(us); 318 return result < 0 ? FAILED : SUCCESS; 319 } 320 321 /* Report a driver-initiated device 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_device_reset(struct us_data *us) 325 { 326 int i; 327 struct Scsi_Host *host = us_to_host(us); 328 329 scsi_report_device_reset(host, 0, 0); 330 if (us->flags & US_FL_SCM_MULT_TARG) { 331 for (i = 1; i < host->max_id; ++i) 332 scsi_report_device_reset(host, 0, i); 333 } 334 } 335 336 /* Report a driver-initiated bus reset to the SCSI layer. 337 * Calling this for a SCSI-initiated reset is unnecessary but harmless. 338 * The caller must not own the SCSI host lock. */ 339 void usb_stor_report_bus_reset(struct us_data *us) 340 { 341 struct Scsi_Host *host = us_to_host(us); 342 343 scsi_lock(host); 344 scsi_report_bus_reset(host, 0); 345 scsi_unlock(host); 346 } 347 348 /*********************************************************************** 349 * /proc/scsi/ functions 350 ***********************************************************************/ 351 352 /* we use this macro to help us write into the buffer */ 353 #undef SPRINTF 354 #define SPRINTF(args...) \ 355 do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0) 356 357 static int proc_info (struct Scsi_Host *host, char *buffer, 358 char **start, off_t offset, int length, int inout) 359 { 360 struct us_data *us = host_to_us(host); 361 char *pos = buffer; 362 const char *string; 363 364 /* if someone is sending us data, just throw it away */ 365 if (inout) 366 return length; 367 368 /* print the controller name */ 369 SPRINTF(" Host scsi%d: usb-storage\n", host->host_no); 370 371 /* print product, vendor, and serial number strings */ 372 if (us->pusb_dev->manufacturer) 373 string = us->pusb_dev->manufacturer; 374 else if (us->unusual_dev->vendorName) 375 string = us->unusual_dev->vendorName; 376 else 377 string = "Unknown"; 378 SPRINTF(" Vendor: %s\n", string); 379 if (us->pusb_dev->product) 380 string = us->pusb_dev->product; 381 else if (us->unusual_dev->productName) 382 string = us->unusual_dev->productName; 383 else 384 string = "Unknown"; 385 SPRINTF(" Product: %s\n", string); 386 if (us->pusb_dev->serial) 387 string = us->pusb_dev->serial; 388 else 389 string = "None"; 390 SPRINTF("Serial Number: %s\n", string); 391 392 /* show the protocol and transport */ 393 SPRINTF(" Protocol: %s\n", us->protocol_name); 394 SPRINTF(" Transport: %s\n", us->transport_name); 395 396 /* show the device flags */ 397 if (pos < buffer + length) { 398 pos += sprintf(pos, " Quirks:"); 399 400 #define US_FLAG(name, value) \ 401 if (us->flags & value) pos += sprintf(pos, " " #name); 402 US_DO_ALL_FLAGS 403 #undef US_FLAG 404 405 *(pos++) = '\n'; 406 } 407 408 /* 409 * Calculate start of next buffer, and return value. 410 */ 411 *start = buffer + offset; 412 413 if ((pos - buffer) < offset) 414 return (0); 415 else if ((pos - buffer - offset) < length) 416 return (pos - buffer - offset); 417 else 418 return (length); 419 } 420 421 /*********************************************************************** 422 * Sysfs interface 423 ***********************************************************************/ 424 425 /* Output routine for the sysfs max_sectors file */ 426 static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf) 427 { 428 struct scsi_device *sdev = to_scsi_device(dev); 429 430 return sprintf(buf, "%u\n", sdev->request_queue->max_sectors); 431 } 432 433 /* Input routine for the sysfs max_sectors file */ 434 static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf, 435 size_t count) 436 { 437 struct scsi_device *sdev = to_scsi_device(dev); 438 unsigned short ms; 439 440 if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) { 441 blk_queue_max_sectors(sdev->request_queue, ms); 442 return strlen(buf); 443 } 444 return -EINVAL; 445 } 446 447 static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors, 448 store_max_sectors); 449 450 static struct device_attribute *sysfs_device_attr_list[] = { 451 &dev_attr_max_sectors, 452 NULL, 453 }; 454 455 /* 456 * this defines our host template, with which we'll allocate hosts 457 */ 458 459 struct scsi_host_template usb_stor_host_template = { 460 /* basic userland interface stuff */ 461 .name = "usb-storage", 462 .proc_name = "usb-storage", 463 .proc_info = proc_info, 464 .info = host_info, 465 466 /* command interface -- queued only */ 467 .queuecommand = queuecommand, 468 469 /* error and abort handlers */ 470 .eh_abort_handler = command_abort, 471 .eh_device_reset_handler = device_reset, 472 .eh_bus_reset_handler = bus_reset, 473 474 /* queue commands only, only one command per LUN */ 475 .can_queue = 1, 476 .cmd_per_lun = 1, 477 478 /* unknown initiator id */ 479 .this_id = -1, 480 481 .slave_alloc = slave_alloc, 482 .slave_configure = slave_configure, 483 484 /* lots of sg segments can be handled */ 485 .sg_tablesize = SG_ALL, 486 487 /* limit the total size of a transfer to 120 KB */ 488 .max_sectors = 240, 489 490 /* merge commands... this seems to help performance, but 491 * periodically someone should test to see which setting is more 492 * optimal. 493 */ 494 .use_clustering = 1, 495 496 /* emulated HBA */ 497 .emulated = 1, 498 499 /* we do our own delay after a device or bus reset */ 500 .skip_settle_delay = 1, 501 502 /* sysfs device attributes */ 503 .sdev_attrs = sysfs_device_attr_list, 504 505 /* module management */ 506 .module = THIS_MODULE 507 }; 508 509 /* To Report "Illegal Request: Invalid Field in CDB */ 510 unsigned char usb_stor_sense_invalidCDB[18] = { 511 [0] = 0x70, /* current error */ 512 [2] = ILLEGAL_REQUEST, /* Illegal Request = 0x05 */ 513 [7] = 0x0a, /* additional length */ 514 [12] = 0x24 /* Invalid Field in CDB */ 515 }; 516 517