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