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 /* USB disks should allow restart. Some drives spin down 181 * automatically, requiring a START-STOP UNIT command. */ 182 sdev->allow_restart = 1; 183 184 } else { 185 186 /* Non-disk-type devices don't need to blacklist any pages 187 * or to force 192-byte transfer lengths for MODE SENSE. 188 * But they do need to use MODE SENSE(10). */ 189 sdev->use_10_for_ms = 1; 190 } 191 192 /* The CB and CBI transports have no way to pass LUN values 193 * other than the bits in the second byte of a CDB. But those 194 * bits don't get set to the LUN value if the device reports 195 * scsi_level == 0 (UNKNOWN). Hence such devices must necessarily 196 * be single-LUN. 197 */ 198 if ((us->protocol == US_PR_CB || us->protocol == US_PR_CBI) && 199 sdev->scsi_level == SCSI_UNKNOWN) 200 us->max_lun = 0; 201 202 /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM 203 * REMOVAL command, so suppress those commands. */ 204 if (us->flags & US_FL_NOT_LOCKABLE) 205 sdev->lockable = 0; 206 207 /* this is to satisfy the compiler, tho I don't think the 208 * return code is ever checked anywhere. */ 209 return 0; 210 } 211 212 /* queue a command */ 213 /* This is always called with scsi_lock(host) held */ 214 static int queuecommand(struct scsi_cmnd *srb, 215 void (*done)(struct scsi_cmnd *)) 216 { 217 struct us_data *us = host_to_us(srb->device->host); 218 219 US_DEBUGP("%s called\n", __FUNCTION__); 220 221 /* check for state-transition errors */ 222 if (us->srb != NULL) { 223 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n", 224 __FUNCTION__, us->srb); 225 return SCSI_MLQUEUE_HOST_BUSY; 226 } 227 228 /* fail the command if we are disconnecting */ 229 if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) { 230 US_DEBUGP("Fail command during disconnect\n"); 231 srb->result = DID_NO_CONNECT << 16; 232 done(srb); 233 return 0; 234 } 235 236 /* enqueue the command and wake up the control thread */ 237 srb->scsi_done = done; 238 us->srb = srb; 239 up(&(us->sema)); 240 241 return 0; 242 } 243 244 /*********************************************************************** 245 * Error handling functions 246 ***********************************************************************/ 247 248 /* Command timeout and abort */ 249 static int command_abort(struct scsi_cmnd *srb) 250 { 251 struct us_data *us = host_to_us(srb->device->host); 252 253 US_DEBUGP("%s called\n", __FUNCTION__); 254 255 /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING 256 * bits are protected by the host lock. */ 257 scsi_lock(us_to_host(us)); 258 259 /* Is this command still active? */ 260 if (us->srb != srb) { 261 scsi_unlock(us_to_host(us)); 262 US_DEBUGP ("-- nothing to abort\n"); 263 return FAILED; 264 } 265 266 /* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if 267 * a device reset isn't already in progress (to avoid interfering 268 * with the reset). Note that we must retain the host lock while 269 * calling usb_stor_stop_transport(); otherwise it might interfere 270 * with an auto-reset that begins as soon as we release the lock. */ 271 set_bit(US_FLIDX_TIMED_OUT, &us->flags); 272 if (!test_bit(US_FLIDX_RESETTING, &us->flags)) { 273 set_bit(US_FLIDX_ABORTING, &us->flags); 274 usb_stor_stop_transport(us); 275 } 276 scsi_unlock(us_to_host(us)); 277 278 /* Wait for the aborted command to finish */ 279 wait_for_completion(&us->notify); 280 return SUCCESS; 281 } 282 283 /* This invokes the transport reset mechanism to reset the state of the 284 * device */ 285 static int device_reset(struct scsi_cmnd *srb) 286 { 287 struct us_data *us = host_to_us(srb->device->host); 288 int result; 289 290 US_DEBUGP("%s called\n", __FUNCTION__); 291 292 /* lock the device pointers and do the reset */ 293 mutex_lock(&(us->dev_mutex)); 294 result = us->transport_reset(us); 295 mutex_unlock(&us->dev_mutex); 296 297 return result < 0 ? FAILED : SUCCESS; 298 } 299 300 /* Simulate a SCSI bus reset by resetting the device's USB port. */ 301 static int bus_reset(struct scsi_cmnd *srb) 302 { 303 struct us_data *us = host_to_us(srb->device->host); 304 int result; 305 306 US_DEBUGP("%s called\n", __FUNCTION__); 307 result = usb_stor_port_reset(us); 308 return result < 0 ? FAILED : SUCCESS; 309 } 310 311 /* Report a driver-initiated device 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_device_reset(struct us_data *us) 315 { 316 int i; 317 struct Scsi_Host *host = us_to_host(us); 318 319 scsi_report_device_reset(host, 0, 0); 320 if (us->flags & US_FL_SCM_MULT_TARG) { 321 for (i = 1; i < host->max_id; ++i) 322 scsi_report_device_reset(host, 0, i); 323 } 324 } 325 326 /* Report a driver-initiated bus reset to the SCSI layer. 327 * Calling this for a SCSI-initiated reset is unnecessary but harmless. 328 * The caller must not own the SCSI host lock. */ 329 void usb_stor_report_bus_reset(struct us_data *us) 330 { 331 struct Scsi_Host *host = us_to_host(us); 332 333 scsi_lock(host); 334 scsi_report_bus_reset(host, 0); 335 scsi_unlock(host); 336 } 337 338 /*********************************************************************** 339 * /proc/scsi/ functions 340 ***********************************************************************/ 341 342 /* we use this macro to help us write into the buffer */ 343 #undef SPRINTF 344 #define SPRINTF(args...) \ 345 do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0) 346 347 static int proc_info (struct Scsi_Host *host, char *buffer, 348 char **start, off_t offset, int length, int inout) 349 { 350 struct us_data *us = host_to_us(host); 351 char *pos = buffer; 352 const char *string; 353 354 /* if someone is sending us data, just throw it away */ 355 if (inout) 356 return length; 357 358 /* print the controller name */ 359 SPRINTF(" Host scsi%d: usb-storage\n", host->host_no); 360 361 /* print product, vendor, and serial number strings */ 362 if (us->pusb_dev->manufacturer) 363 string = us->pusb_dev->manufacturer; 364 else if (us->unusual_dev->vendorName) 365 string = us->unusual_dev->vendorName; 366 else 367 string = "Unknown"; 368 SPRINTF(" Vendor: %s\n", string); 369 if (us->pusb_dev->product) 370 string = us->pusb_dev->product; 371 else if (us->unusual_dev->productName) 372 string = us->unusual_dev->productName; 373 else 374 string = "Unknown"; 375 SPRINTF(" Product: %s\n", string); 376 if (us->pusb_dev->serial) 377 string = us->pusb_dev->serial; 378 else 379 string = "None"; 380 SPRINTF("Serial Number: %s\n", string); 381 382 /* show the protocol and transport */ 383 SPRINTF(" Protocol: %s\n", us->protocol_name); 384 SPRINTF(" Transport: %s\n", us->transport_name); 385 386 /* show the device flags */ 387 if (pos < buffer + length) { 388 pos += sprintf(pos, " Quirks:"); 389 390 #define US_FLAG(name, value) \ 391 if (us->flags & value) pos += sprintf(pos, " " #name); 392 US_DO_ALL_FLAGS 393 #undef US_FLAG 394 395 *(pos++) = '\n'; 396 } 397 398 /* 399 * Calculate start of next buffer, and return value. 400 */ 401 *start = buffer + offset; 402 403 if ((pos - buffer) < offset) 404 return (0); 405 else if ((pos - buffer - offset) < length) 406 return (pos - buffer - offset); 407 else 408 return (length); 409 } 410 411 /*********************************************************************** 412 * Sysfs interface 413 ***********************************************************************/ 414 415 /* Output routine for the sysfs max_sectors file */ 416 static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf) 417 { 418 struct scsi_device *sdev = to_scsi_device(dev); 419 420 return sprintf(buf, "%u\n", sdev->request_queue->max_sectors); 421 } 422 423 /* Input routine for the sysfs max_sectors file */ 424 static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf, 425 size_t count) 426 { 427 struct scsi_device *sdev = to_scsi_device(dev); 428 unsigned short ms; 429 430 if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) { 431 blk_queue_max_sectors(sdev->request_queue, ms); 432 return strlen(buf); 433 } 434 return -EINVAL; 435 } 436 437 static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors, 438 store_max_sectors); 439 440 static struct device_attribute *sysfs_device_attr_list[] = { 441 &dev_attr_max_sectors, 442 NULL, 443 }; 444 445 /* 446 * this defines our host template, with which we'll allocate hosts 447 */ 448 449 struct scsi_host_template usb_stor_host_template = { 450 /* basic userland interface stuff */ 451 .name = "usb-storage", 452 .proc_name = "usb-storage", 453 .proc_info = proc_info, 454 .info = host_info, 455 456 /* command interface -- queued only */ 457 .queuecommand = queuecommand, 458 459 /* error and abort handlers */ 460 .eh_abort_handler = command_abort, 461 .eh_device_reset_handler = device_reset, 462 .eh_bus_reset_handler = bus_reset, 463 464 /* queue commands only, only one command per LUN */ 465 .can_queue = 1, 466 .cmd_per_lun = 1, 467 468 /* unknown initiator id */ 469 .this_id = -1, 470 471 .slave_alloc = slave_alloc, 472 .slave_configure = slave_configure, 473 474 /* lots of sg segments can be handled */ 475 .sg_tablesize = SG_ALL, 476 477 /* limit the total size of a transfer to 120 KB */ 478 .max_sectors = 240, 479 480 /* merge commands... this seems to help performance, but 481 * periodically someone should test to see which setting is more 482 * optimal. 483 */ 484 .use_clustering = 1, 485 486 /* emulated HBA */ 487 .emulated = 1, 488 489 /* we do our own delay after a device or bus reset */ 490 .skip_settle_delay = 1, 491 492 /* sysfs device attributes */ 493 .sdev_attrs = sysfs_device_attr_list, 494 495 /* module management */ 496 .module = THIS_MODULE 497 }; 498 499 /* To Report "Illegal Request: Invalid Field in CDB */ 500 unsigned char usb_stor_sense_invalidCDB[18] = { 501 [0] = 0x70, /* current error */ 502 [2] = ILLEGAL_REQUEST, /* Illegal Request = 0x05 */ 503 [7] = 0x0a, /* additional length */ 504 [12] = 0x24 /* Invalid Field in CDB */ 505 }; 506 507