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 = 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 } else { 159 160 /* Non-disk-type devices don't need to blacklist any pages 161 * or to force 192-byte transfer lengths for MODE SENSE. 162 * But they do need to use MODE SENSE(10). */ 163 sdev->use_10_for_ms = 1; 164 } 165 166 /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM 167 * REMOVAL command, so suppress those commands. */ 168 if (us->flags & US_FL_NOT_LOCKABLE) 169 sdev->lockable = 0; 170 171 /* this is to satisfy the compiler, tho I don't think the 172 * return code is ever checked anywhere. */ 173 return 0; 174 } 175 176 /* queue a command */ 177 /* This is always called with scsi_lock(host) held */ 178 static int queuecommand(struct scsi_cmnd *srb, 179 void (*done)(struct scsi_cmnd *)) 180 { 181 struct us_data *us = host_to_us(srb->device->host); 182 183 US_DEBUGP("%s called\n", __FUNCTION__); 184 185 /* check for state-transition errors */ 186 if (us->srb != NULL) { 187 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n", 188 __FUNCTION__, us->srb); 189 return SCSI_MLQUEUE_HOST_BUSY; 190 } 191 192 /* fail the command if we are disconnecting */ 193 if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) { 194 US_DEBUGP("Fail command during disconnect\n"); 195 srb->result = DID_NO_CONNECT << 16; 196 done(srb); 197 return 0; 198 } 199 200 /* enqueue the command and wake up the control thread */ 201 srb->scsi_done = done; 202 us->srb = srb; 203 up(&(us->sema)); 204 205 return 0; 206 } 207 208 /*********************************************************************** 209 * Error handling functions 210 ***********************************************************************/ 211 212 /* Command timeout and abort */ 213 /* This is always called with scsi_lock(host) held */ 214 static int command_abort(struct scsi_cmnd *srb) 215 { 216 struct us_data *us = host_to_us(srb->device->host); 217 218 US_DEBUGP("%s called\n", __FUNCTION__); 219 220 /* Is this command still active? */ 221 if (us->srb != srb) { 222 US_DEBUGP ("-- nothing to abort\n"); 223 return FAILED; 224 } 225 226 /* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if 227 * a device reset isn't already in progress (to avoid interfering 228 * with the reset). To prevent races with auto-reset, we must 229 * stop any ongoing USB transfers while still holding the host 230 * lock. */ 231 set_bit(US_FLIDX_TIMED_OUT, &us->flags); 232 if (!test_bit(US_FLIDX_RESETTING, &us->flags)) { 233 set_bit(US_FLIDX_ABORTING, &us->flags); 234 usb_stor_stop_transport(us); 235 } 236 237 /* Wait for the aborted command to finish */ 238 wait_for_completion(&us->notify); 239 240 /* Reacquire the lock and allow USB transfers to resume */ 241 clear_bit(US_FLIDX_ABORTING, &us->flags); 242 clear_bit(US_FLIDX_TIMED_OUT, &us->flags); 243 return SUCCESS; 244 } 245 246 /* This invokes the transport reset mechanism to reset the state of the 247 * device */ 248 /* This is always called with scsi_lock(host) held */ 249 static int device_reset(struct scsi_cmnd *srb) 250 { 251 struct us_data *us = host_to_us(srb->device->host); 252 int result; 253 254 US_DEBUGP("%s called\n", __FUNCTION__); 255 256 /* lock the device pointers and do the reset */ 257 down(&(us->dev_semaphore)); 258 if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) { 259 result = FAILED; 260 US_DEBUGP("No reset during disconnect\n"); 261 } else 262 result = us->transport_reset(us); 263 up(&(us->dev_semaphore)); 264 265 return result; 266 } 267 268 /* This resets the device's USB port. */ 269 /* It refuses to work if there's more than one interface in 270 * the device, so that other users are not affected. */ 271 /* This is always called with scsi_lock(host) held */ 272 static int bus_reset(struct scsi_cmnd *srb) 273 { 274 struct us_data *us = host_to_us(srb->device->host); 275 int result, rc; 276 277 US_DEBUGP("%s called\n", __FUNCTION__); 278 279 /* The USB subsystem doesn't handle synchronisation between 280 * a device's several drivers. Therefore we reset only devices 281 * with just one interface, which we of course own. */ 282 283 down(&(us->dev_semaphore)); 284 if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) { 285 result = -EIO; 286 US_DEBUGP("No reset during disconnect\n"); 287 } else if (us->pusb_dev->actconfig->desc.bNumInterfaces != 1) { 288 result = -EBUSY; 289 US_DEBUGP("Refusing to reset a multi-interface device\n"); 290 } else { 291 rc = usb_lock_device_for_reset(us->pusb_dev, us->pusb_intf); 292 if (rc < 0) { 293 US_DEBUGP("unable to lock device for reset: %d\n", rc); 294 result = rc; 295 } else { 296 result = usb_reset_device(us->pusb_dev); 297 if (rc) 298 usb_unlock_device(us->pusb_dev); 299 US_DEBUGP("usb_reset_device returns %d\n", result); 300 } 301 } 302 up(&(us->dev_semaphore)); 303 304 /* lock the host for the return */ 305 return result < 0 ? FAILED : SUCCESS; 306 } 307 308 /* Report a driver-initiated device reset to the SCSI layer. 309 * Calling this for a SCSI-initiated reset is unnecessary but harmless. 310 * The caller must own the SCSI host lock. */ 311 void usb_stor_report_device_reset(struct us_data *us) 312 { 313 int i; 314 struct Scsi_Host *host = us_to_host(us); 315 316 scsi_report_device_reset(host, 0, 0); 317 if (us->flags & US_FL_SCM_MULT_TARG) { 318 for (i = 1; i < host->max_id; ++i) 319 scsi_report_device_reset(host, 0, i); 320 } 321 } 322 323 /*********************************************************************** 324 * /proc/scsi/ functions 325 ***********************************************************************/ 326 327 /* we use this macro to help us write into the buffer */ 328 #undef SPRINTF 329 #define SPRINTF(args...) \ 330 do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0) 331 332 static int proc_info (struct Scsi_Host *host, char *buffer, 333 char **start, off_t offset, int length, int inout) 334 { 335 struct us_data *us = host_to_us(host); 336 char *pos = buffer; 337 const char *string; 338 339 /* if someone is sending us data, just throw it away */ 340 if (inout) 341 return length; 342 343 /* print the controller name */ 344 SPRINTF(" Host scsi%d: usb-storage\n", host->host_no); 345 346 /* print product, vendor, and serial number strings */ 347 if (us->pusb_dev->manufacturer) 348 string = us->pusb_dev->manufacturer; 349 else if (us->unusual_dev->vendorName) 350 string = us->unusual_dev->vendorName; 351 else 352 string = "Unknown"; 353 SPRINTF(" Vendor: %s\n", string); 354 if (us->pusb_dev->product) 355 string = us->pusb_dev->product; 356 else if (us->unusual_dev->productName) 357 string = us->unusual_dev->productName; 358 else 359 string = "Unknown"; 360 SPRINTF(" Product: %s\n", string); 361 if (us->pusb_dev->serial) 362 string = us->pusb_dev->serial; 363 else 364 string = "None"; 365 SPRINTF("Serial Number: %s\n", string); 366 367 /* show the protocol and transport */ 368 SPRINTF(" Protocol: %s\n", us->protocol_name); 369 SPRINTF(" Transport: %s\n", us->transport_name); 370 371 /* show the device flags */ 372 if (pos < buffer + length) { 373 pos += sprintf(pos, " Quirks:"); 374 375 #define US_FLAG(name, value) \ 376 if (us->flags & value) pos += sprintf(pos, " " #name); 377 US_DO_ALL_FLAGS 378 #undef US_FLAG 379 380 *(pos++) = '\n'; 381 } 382 383 /* 384 * Calculate start of next buffer, and return value. 385 */ 386 *start = buffer + offset; 387 388 if ((pos - buffer) < offset) 389 return (0); 390 else if ((pos - buffer - offset) < length) 391 return (pos - buffer - offset); 392 else 393 return (length); 394 } 395 396 /*********************************************************************** 397 * Sysfs interface 398 ***********************************************************************/ 399 400 /* Output routine for the sysfs max_sectors file */ 401 static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf) 402 { 403 struct scsi_device *sdev = to_scsi_device(dev); 404 405 return sprintf(buf, "%u\n", sdev->request_queue->max_sectors); 406 } 407 408 /* Input routine for the sysfs max_sectors file */ 409 static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf, 410 size_t count) 411 { 412 struct scsi_device *sdev = to_scsi_device(dev); 413 unsigned short ms; 414 415 if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) { 416 blk_queue_max_sectors(sdev->request_queue, ms); 417 return strlen(buf); 418 } 419 return -EINVAL; 420 } 421 422 static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors, 423 store_max_sectors); 424 425 static struct device_attribute *sysfs_device_attr_list[] = { 426 &dev_attr_max_sectors, 427 NULL, 428 }; 429 430 /* 431 * this defines our host template, with which we'll allocate hosts 432 */ 433 434 struct scsi_host_template usb_stor_host_template = { 435 /* basic userland interface stuff */ 436 .name = "usb-storage", 437 .proc_name = "usb-storage", 438 .proc_info = proc_info, 439 .info = host_info, 440 441 /* command interface -- queued only */ 442 .queuecommand = queuecommand, 443 444 /* error and abort handlers */ 445 .eh_abort_handler = command_abort, 446 .eh_device_reset_handler = device_reset, 447 .eh_bus_reset_handler = bus_reset, 448 449 /* queue commands only, only one command per LUN */ 450 .can_queue = 1, 451 .cmd_per_lun = 1, 452 453 /* unknown initiator id */ 454 .this_id = -1, 455 456 .slave_alloc = slave_alloc, 457 .slave_configure = slave_configure, 458 459 /* lots of sg segments can be handled */ 460 .sg_tablesize = SG_ALL, 461 462 /* limit the total size of a transfer to 120 KB */ 463 .max_sectors = 240, 464 465 /* merge commands... this seems to help performance, but 466 * periodically someone should test to see which setting is more 467 * optimal. 468 */ 469 .use_clustering = 1, 470 471 /* emulated HBA */ 472 .emulated = 1, 473 474 /* we do our own delay after a device or bus reset */ 475 .skip_settle_delay = 1, 476 477 /* sysfs device attributes */ 478 .sdev_attrs = sysfs_device_attr_list, 479 480 /* module management */ 481 .module = THIS_MODULE 482 }; 483 484 /* To Report "Illegal Request: Invalid Field in CDB */ 485 unsigned char usb_stor_sense_invalidCDB[18] = { 486 [0] = 0x70, /* current error */ 487 [2] = ILLEGAL_REQUEST, /* Illegal Request = 0x05 */ 488 [7] = 0x0a, /* additional length */ 489 [12] = 0x24 /* Invalid Field in CDB */ 490 }; 491 492