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 struct usb_host_endpoint *bulk_in_ep; 77 78 /* 79 * Set the INQUIRY transfer length to 36. We don't use any of 80 * the extra data and many devices choke if asked for more or 81 * less than 36 bytes. 82 */ 83 sdev->inquiry_len = 36; 84 85 /* Scatter-gather buffers (all but the last) must have a length 86 * divisible by the bulk maxpacket size. Otherwise a data packet 87 * would end up being short, causing a premature end to the data 88 * transfer. We'll use the maxpacket value of the bulk-IN pipe 89 * to set the SCSI device queue's DMA alignment mask. 90 */ 91 bulk_in_ep = us->pusb_dev->ep_in[usb_pipeendpoint(us->recv_bulk_pipe)]; 92 blk_queue_update_dma_alignment(sdev->request_queue, 93 le16_to_cpu(bulk_in_ep->desc.wMaxPacketSize) - 1); 94 /* wMaxPacketSize must be a power of 2 */ 95 96 /* 97 * The UFI spec treates the Peripheral Qualifier bits in an 98 * INQUIRY result as reserved and requires devices to set them 99 * to 0. However the SCSI spec requires these bits to be set 100 * to 3 to indicate when a LUN is not present. 101 * 102 * Let the scanning code know if this target merely sets 103 * Peripheral Device Type to 0x1f to indicate no LUN. 104 */ 105 if (us->subclass == US_SC_UFI) 106 sdev->sdev_target->pdt_1f_for_no_lun = 1; 107 108 return 0; 109 } 110 111 static int slave_configure(struct scsi_device *sdev) 112 { 113 struct us_data *us = host_to_us(sdev->host); 114 115 /* Many devices have trouble transfering more than 32KB at a time, 116 * while others have trouble with more than 64K. At this time we 117 * are limiting both to 32K (64 sectores). 118 */ 119 if (us->flags & (US_FL_MAX_SECTORS_64 | US_FL_MAX_SECTORS_MIN)) { 120 unsigned int max_sectors = 64; 121 122 if (us->flags & US_FL_MAX_SECTORS_MIN) 123 max_sectors = PAGE_CACHE_SIZE >> 9; 124 if (sdev->request_queue->max_sectors > max_sectors) 125 blk_queue_max_sectors(sdev->request_queue, 126 max_sectors); 127 } 128 129 /* We can't put these settings in slave_alloc() because that gets 130 * called before the device type is known. Consequently these 131 * settings can't be overridden via the scsi devinfo mechanism. */ 132 if (sdev->type == TYPE_DISK) { 133 134 /* Disk-type devices use MODE SENSE(6) if the protocol 135 * (SubClass) is Transparent SCSI, otherwise they use 136 * MODE SENSE(10). */ 137 if (us->subclass != US_SC_SCSI && us->subclass != US_SC_CYP_ATACB) 138 sdev->use_10_for_ms = 1; 139 140 /* Many disks only accept MODE SENSE transfer lengths of 141 * 192 bytes (that's what Windows uses). */ 142 sdev->use_192_bytes_for_3f = 1; 143 144 /* Some devices don't like MODE SENSE with page=0x3f, 145 * which is the command used for checking if a device 146 * is write-protected. Now that we tell the sd driver 147 * to do a 192-byte transfer with this command the 148 * majority of devices work fine, but a few still can't 149 * handle it. The sd driver will simply assume those 150 * devices are write-enabled. */ 151 if (us->flags & US_FL_NO_WP_DETECT) 152 sdev->skip_ms_page_3f = 1; 153 154 /* A number of devices have problems with MODE SENSE for 155 * page x08, so we will skip it. */ 156 sdev->skip_ms_page_8 = 1; 157 158 /* Some disks return the total number of blocks in response 159 * to READ CAPACITY rather than the highest block number. 160 * If this device makes that mistake, tell the sd driver. */ 161 if (us->flags & US_FL_FIX_CAPACITY) 162 sdev->fix_capacity = 1; 163 164 /* A few disks have two indistinguishable version, one of 165 * which reports the correct capacity and the other does not. 166 * The sd driver has to guess which is the case. */ 167 if (us->flags & US_FL_CAPACITY_HEURISTICS) 168 sdev->guess_capacity = 1; 169 170 /* Some devices report a SCSI revision level above 2 but are 171 * unable to handle the REPORT LUNS command (for which 172 * support is mandatory at level 3). Since we already have 173 * a Get-Max-LUN request, we won't lose much by setting the 174 * revision level down to 2. The only devices that would be 175 * affected are those with sparse LUNs. */ 176 if (sdev->scsi_level > SCSI_2) 177 sdev->sdev_target->scsi_level = 178 sdev->scsi_level = SCSI_2; 179 180 /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable 181 * Hardware Error) when any low-level error occurs, 182 * recoverable or not. Setting this flag tells the SCSI 183 * midlayer to retry such commands, which frequently will 184 * succeed and fix the error. The worst this can lead to 185 * is an occasional series of retries that will all fail. */ 186 sdev->retry_hwerror = 1; 187 188 /* USB disks should allow restart. Some drives spin down 189 * automatically, requiring a START-STOP UNIT command. */ 190 sdev->allow_restart = 1; 191 192 /* Some USB cardreaders have trouble reading an sdcard's last 193 * sector in a larger then 1 sector read, since the performance 194 * impact is negible we set this flag for all USB disks */ 195 sdev->last_sector_bug = 1; 196 } else { 197 198 /* Non-disk-type devices don't need to blacklist any pages 199 * or to force 192-byte transfer lengths for MODE SENSE. 200 * But they do need to use MODE SENSE(10). */ 201 sdev->use_10_for_ms = 1; 202 } 203 204 /* The CB and CBI transports have no way to pass LUN values 205 * other than the bits in the second byte of a CDB. But those 206 * bits don't get set to the LUN value if the device reports 207 * scsi_level == 0 (UNKNOWN). Hence such devices must necessarily 208 * be single-LUN. 209 */ 210 if ((us->protocol == US_PR_CB || us->protocol == US_PR_CBI) && 211 sdev->scsi_level == SCSI_UNKNOWN) 212 us->max_lun = 0; 213 214 /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM 215 * REMOVAL command, so suppress those commands. */ 216 if (us->flags & US_FL_NOT_LOCKABLE) 217 sdev->lockable = 0; 218 219 /* this is to satisfy the compiler, tho I don't think the 220 * return code is ever checked anywhere. */ 221 return 0; 222 } 223 224 /* queue a command */ 225 /* This is always called with scsi_lock(host) held */ 226 static int queuecommand(struct scsi_cmnd *srb, 227 void (*done)(struct scsi_cmnd *)) 228 { 229 struct us_data *us = host_to_us(srb->device->host); 230 231 US_DEBUGP("%s called\n", __func__); 232 233 /* check for state-transition errors */ 234 if (us->srb != NULL) { 235 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n", 236 __func__, us->srb); 237 return SCSI_MLQUEUE_HOST_BUSY; 238 } 239 240 /* fail the command if we are disconnecting */ 241 if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) { 242 US_DEBUGP("Fail command during disconnect\n"); 243 srb->result = DID_NO_CONNECT << 16; 244 done(srb); 245 return 0; 246 } 247 248 /* enqueue the command and wake up the control thread */ 249 srb->scsi_done = done; 250 us->srb = srb; 251 up(&(us->sema)); 252 253 return 0; 254 } 255 256 /*********************************************************************** 257 * Error handling functions 258 ***********************************************************************/ 259 260 /* Command timeout and abort */ 261 static int command_abort(struct scsi_cmnd *srb) 262 { 263 struct us_data *us = host_to_us(srb->device->host); 264 265 US_DEBUGP("%s called\n", __func__); 266 267 /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING 268 * bits are protected by the host lock. */ 269 scsi_lock(us_to_host(us)); 270 271 /* Is this command still active? */ 272 if (us->srb != srb) { 273 scsi_unlock(us_to_host(us)); 274 US_DEBUGP ("-- nothing to abort\n"); 275 return FAILED; 276 } 277 278 /* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if 279 * a device reset isn't already in progress (to avoid interfering 280 * with the reset). Note that we must retain the host lock while 281 * calling usb_stor_stop_transport(); otherwise it might interfere 282 * with an auto-reset that begins as soon as we release the lock. */ 283 set_bit(US_FLIDX_TIMED_OUT, &us->flags); 284 if (!test_bit(US_FLIDX_RESETTING, &us->flags)) { 285 set_bit(US_FLIDX_ABORTING, &us->flags); 286 usb_stor_stop_transport(us); 287 } 288 scsi_unlock(us_to_host(us)); 289 290 /* Wait for the aborted command to finish */ 291 wait_for_completion(&us->notify); 292 return SUCCESS; 293 } 294 295 /* This invokes the transport reset mechanism to reset the state of the 296 * device */ 297 static int device_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", __func__); 303 304 /* lock the device pointers and do the reset */ 305 mutex_lock(&(us->dev_mutex)); 306 result = us->transport_reset(us); 307 mutex_unlock(&us->dev_mutex); 308 309 return result < 0 ? FAILED : SUCCESS; 310 } 311 312 /* Simulate a SCSI bus reset by resetting the device's USB port. */ 313 static int bus_reset(struct scsi_cmnd *srb) 314 { 315 struct us_data *us = host_to_us(srb->device->host); 316 int result; 317 318 US_DEBUGP("%s called\n", __func__); 319 result = usb_stor_port_reset(us); 320 return result < 0 ? FAILED : SUCCESS; 321 } 322 323 /* Report a driver-initiated device reset to the SCSI layer. 324 * Calling this for a SCSI-initiated reset is unnecessary but harmless. 325 * The caller must own the SCSI host lock. */ 326 void usb_stor_report_device_reset(struct us_data *us) 327 { 328 int i; 329 struct Scsi_Host *host = us_to_host(us); 330 331 scsi_report_device_reset(host, 0, 0); 332 if (us->flags & US_FL_SCM_MULT_TARG) { 333 for (i = 1; i < host->max_id; ++i) 334 scsi_report_device_reset(host, 0, i); 335 } 336 } 337 338 /* Report a driver-initiated bus reset to the SCSI layer. 339 * Calling this for a SCSI-initiated reset is unnecessary but harmless. 340 * The caller must not own the SCSI host lock. */ 341 void usb_stor_report_bus_reset(struct us_data *us) 342 { 343 struct Scsi_Host *host = us_to_host(us); 344 345 scsi_lock(host); 346 scsi_report_bus_reset(host, 0); 347 scsi_unlock(host); 348 } 349 350 /*********************************************************************** 351 * /proc/scsi/ functions 352 ***********************************************************************/ 353 354 /* we use this macro to help us write into the buffer */ 355 #undef SPRINTF 356 #define SPRINTF(args...) \ 357 do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0) 358 359 static int proc_info (struct Scsi_Host *host, char *buffer, 360 char **start, off_t offset, int length, int inout) 361 { 362 struct us_data *us = host_to_us(host); 363 char *pos = buffer; 364 const char *string; 365 366 /* if someone is sending us data, just throw it away */ 367 if (inout) 368 return length; 369 370 /* print the controller name */ 371 SPRINTF(" Host scsi%d: usb-storage\n", host->host_no); 372 373 /* print product, vendor, and serial number strings */ 374 if (us->pusb_dev->manufacturer) 375 string = us->pusb_dev->manufacturer; 376 else if (us->unusual_dev->vendorName) 377 string = us->unusual_dev->vendorName; 378 else 379 string = "Unknown"; 380 SPRINTF(" Vendor: %s\n", string); 381 if (us->pusb_dev->product) 382 string = us->pusb_dev->product; 383 else if (us->unusual_dev->productName) 384 string = us->unusual_dev->productName; 385 else 386 string = "Unknown"; 387 SPRINTF(" Product: %s\n", string); 388 if (us->pusb_dev->serial) 389 string = us->pusb_dev->serial; 390 else 391 string = "None"; 392 SPRINTF("Serial Number: %s\n", string); 393 394 /* show the protocol and transport */ 395 SPRINTF(" Protocol: %s\n", us->protocol_name); 396 SPRINTF(" Transport: %s\n", us->transport_name); 397 398 /* show the device flags */ 399 if (pos < buffer + length) { 400 pos += sprintf(pos, " Quirks:"); 401 402 #define US_FLAG(name, value) \ 403 if (us->flags & value) pos += sprintf(pos, " " #name); 404 US_DO_ALL_FLAGS 405 #undef US_FLAG 406 407 *(pos++) = '\n'; 408 } 409 410 /* 411 * Calculate start of next buffer, and return value. 412 */ 413 *start = buffer + offset; 414 415 if ((pos - buffer) < offset) 416 return (0); 417 else if ((pos - buffer - offset) < length) 418 return (pos - buffer - offset); 419 else 420 return (length); 421 } 422 423 /*********************************************************************** 424 * Sysfs interface 425 ***********************************************************************/ 426 427 /* Output routine for the sysfs max_sectors file */ 428 static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf) 429 { 430 struct scsi_device *sdev = to_scsi_device(dev); 431 432 return sprintf(buf, "%u\n", sdev->request_queue->max_sectors); 433 } 434 435 /* Input routine for the sysfs max_sectors file */ 436 static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf, 437 size_t count) 438 { 439 struct scsi_device *sdev = to_scsi_device(dev); 440 unsigned short ms; 441 442 if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) { 443 blk_queue_max_sectors(sdev->request_queue, ms); 444 return strlen(buf); 445 } 446 return -EINVAL; 447 } 448 449 static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors, 450 store_max_sectors); 451 452 static struct device_attribute *sysfs_device_attr_list[] = { 453 &dev_attr_max_sectors, 454 NULL, 455 }; 456 457 /* 458 * this defines our host template, with which we'll allocate hosts 459 */ 460 461 struct scsi_host_template usb_stor_host_template = { 462 /* basic userland interface stuff */ 463 .name = "usb-storage", 464 .proc_name = "usb-storage", 465 .proc_info = proc_info, 466 .info = host_info, 467 468 /* command interface -- queued only */ 469 .queuecommand = queuecommand, 470 471 /* error and abort handlers */ 472 .eh_abort_handler = command_abort, 473 .eh_device_reset_handler = device_reset, 474 .eh_bus_reset_handler = bus_reset, 475 476 /* queue commands only, only one command per LUN */ 477 .can_queue = 1, 478 .cmd_per_lun = 1, 479 480 /* unknown initiator id */ 481 .this_id = -1, 482 483 .slave_alloc = slave_alloc, 484 .slave_configure = slave_configure, 485 486 /* lots of sg segments can be handled */ 487 .sg_tablesize = SG_ALL, 488 489 /* limit the total size of a transfer to 120 KB */ 490 .max_sectors = 240, 491 492 /* merge commands... this seems to help performance, but 493 * periodically someone should test to see which setting is more 494 * optimal. 495 */ 496 .use_clustering = 1, 497 498 /* emulated HBA */ 499 .emulated = 1, 500 501 /* we do our own delay after a device or bus reset */ 502 .skip_settle_delay = 1, 503 504 /* sysfs device attributes */ 505 .sdev_attrs = sysfs_device_attr_list, 506 507 /* module management */ 508 .module = THIS_MODULE 509 }; 510 511 /* To Report "Illegal Request: Invalid Field in CDB */ 512 unsigned char usb_stor_sense_invalidCDB[18] = { 513 [0] = 0x70, /* current error */ 514 [2] = ILLEGAL_REQUEST, /* Illegal Request = 0x05 */ 515 [7] = 0x0a, /* additional length */ 516 [12] = 0x24 /* Invalid Field in CDB */ 517 }; 518 519