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 /* 76 * Set the INQUIRY transfer length to 36. We don't use any of 77 * the extra data and many devices choke if asked for more or 78 * less than 36 bytes. 79 */ 80 sdev->inquiry_len = 36; 81 return 0; 82 } 83 84 static int slave_configure(struct scsi_device *sdev) 85 { 86 struct us_data *us = host_to_us(sdev->host); 87 88 /* Scatter-gather buffers (all but the last) must have a length 89 * divisible by the bulk maxpacket size. Otherwise a data packet 90 * would end up being short, causing a premature end to the data 91 * transfer. Since high-speed bulk pipes have a maxpacket size 92 * of 512, we'll use that as the scsi device queue's DMA alignment 93 * mask. Guaranteeing proper alignment of the first buffer will 94 * have the desired effect because, except at the beginning and 95 * the end, scatter-gather buffers follow page boundaries. */ 96 blk_queue_dma_alignment(sdev->request_queue, (512 - 1)); 97 98 /* Set the SCSI level to at least 2. We'll leave it at 3 if that's 99 * what is originally reported. We need this to avoid confusing 100 * the SCSI layer with devices that report 0 or 1, but need 10-byte 101 * commands (ala ATAPI devices behind certain bridges, or devices 102 * which simply have broken INQUIRY data). 103 * 104 * NOTE: This means /dev/sg programs (ala cdrecord) will get the 105 * actual information. This seems to be the preference for 106 * programs like that. 107 * 108 * NOTE: This also means that /proc/scsi/scsi and sysfs may report 109 * the actual value or the modified one, depending on where the 110 * data comes from. 111 */ 112 if (sdev->scsi_level < SCSI_2) 113 sdev->scsi_level = sdev->sdev_target->scsi_level = SCSI_2; 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) && 120 sdev->request_queue->max_sectors > 64) 121 blk_queue_max_sectors(sdev->request_queue, 64); 122 123 /* We can't put these settings in slave_alloc() because that gets 124 * called before the device type is known. Consequently these 125 * settings can't be overridden via the scsi devinfo mechanism. */ 126 if (sdev->type == TYPE_DISK) { 127 128 /* Disk-type devices use MODE SENSE(6) if the protocol 129 * (SubClass) is Transparent SCSI, otherwise they use 130 * MODE SENSE(10). */ 131 if (us->subclass != US_SC_SCSI) 132 sdev->use_10_for_ms = 1; 133 134 /* Many disks only accept MODE SENSE transfer lengths of 135 * 192 bytes (that's what Windows uses). */ 136 sdev->use_192_bytes_for_3f = 1; 137 138 /* Some devices don't like MODE SENSE with page=0x3f, 139 * which is the command used for checking if a device 140 * is write-protected. Now that we tell the sd driver 141 * to do a 192-byte transfer with this command the 142 * majority of devices work fine, but a few still can't 143 * handle it. The sd driver will simply assume those 144 * devices are write-enabled. */ 145 if (us->flags & US_FL_NO_WP_DETECT) 146 sdev->skip_ms_page_3f = 1; 147 148 /* A number of devices have problems with MODE SENSE for 149 * page x08, so we will skip it. */ 150 sdev->skip_ms_page_8 = 1; 151 152 /* Some disks return the total number of blocks in response 153 * to READ CAPACITY rather than the highest block number. 154 * If this device makes that mistake, tell the sd driver. */ 155 if (us->flags & US_FL_FIX_CAPACITY) 156 sdev->fix_capacity = 1; 157 158 /* Some devices report a SCSI revision level above 2 but are 159 * unable to handle the REPORT LUNS command (for which 160 * support is mandatory at level 3). Since we already have 161 * a Get-Max-LUN request, we won't lose much by setting the 162 * revision level down to 2. The only devices that would be 163 * affected are those with sparse LUNs. */ 164 sdev->scsi_level = sdev->sdev_target->scsi_level = SCSI_2; 165 166 /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable 167 * Hardware Error) when any low-level error occurs, 168 * recoverable or not. Setting this flag tells the SCSI 169 * midlayer to retry such commands, which frequently will 170 * succeed and fix the error. The worst this can lead to 171 * is an occasional series of retries that will all fail. */ 172 sdev->retry_hwerror = 1; 173 174 } else { 175 176 /* Non-disk-type devices don't need to blacklist any pages 177 * or to force 192-byte transfer lengths for MODE SENSE. 178 * But they do need to use MODE SENSE(10). */ 179 sdev->use_10_for_ms = 1; 180 } 181 182 /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM 183 * REMOVAL command, so suppress those commands. */ 184 if (us->flags & US_FL_NOT_LOCKABLE) 185 sdev->lockable = 0; 186 187 /* this is to satisfy the compiler, tho I don't think the 188 * return code is ever checked anywhere. */ 189 return 0; 190 } 191 192 /* queue a command */ 193 /* This is always called with scsi_lock(host) held */ 194 static int queuecommand(struct scsi_cmnd *srb, 195 void (*done)(struct scsi_cmnd *)) 196 { 197 struct us_data *us = host_to_us(srb->device->host); 198 199 US_DEBUGP("%s called\n", __FUNCTION__); 200 201 /* check for state-transition errors */ 202 if (us->srb != NULL) { 203 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n", 204 __FUNCTION__, us->srb); 205 return SCSI_MLQUEUE_HOST_BUSY; 206 } 207 208 /* fail the command if we are disconnecting */ 209 if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) { 210 US_DEBUGP("Fail command during disconnect\n"); 211 srb->result = DID_NO_CONNECT << 16; 212 done(srb); 213 return 0; 214 } 215 216 /* enqueue the command and wake up the control thread */ 217 srb->scsi_done = done; 218 us->srb = srb; 219 up(&(us->sema)); 220 221 return 0; 222 } 223 224 /*********************************************************************** 225 * Error handling functions 226 ***********************************************************************/ 227 228 /* Command timeout and abort */ 229 static int command_abort(struct scsi_cmnd *srb) 230 { 231 struct us_data *us = host_to_us(srb->device->host); 232 233 US_DEBUGP("%s called\n", __FUNCTION__); 234 235 /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING 236 * bits are protected by the host lock. */ 237 scsi_lock(us_to_host(us)); 238 239 /* Is this command still active? */ 240 if (us->srb != srb) { 241 scsi_unlock(us_to_host(us)); 242 US_DEBUGP ("-- nothing to abort\n"); 243 return FAILED; 244 } 245 246 /* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if 247 * a device reset isn't already in progress (to avoid interfering 248 * with the reset). Note that we must retain the host lock while 249 * calling usb_stor_stop_transport(); otherwise it might interfere 250 * with an auto-reset that begins as soon as we release the lock. */ 251 set_bit(US_FLIDX_TIMED_OUT, &us->flags); 252 if (!test_bit(US_FLIDX_RESETTING, &us->flags)) { 253 set_bit(US_FLIDX_ABORTING, &us->flags); 254 usb_stor_stop_transport(us); 255 } 256 scsi_unlock(us_to_host(us)); 257 258 /* Wait for the aborted command to finish */ 259 wait_for_completion(&us->notify); 260 return SUCCESS; 261 } 262 263 /* This invokes the transport reset mechanism to reset the state of the 264 * device */ 265 static int device_reset(struct scsi_cmnd *srb) 266 { 267 struct us_data *us = host_to_us(srb->device->host); 268 int result; 269 270 US_DEBUGP("%s called\n", __FUNCTION__); 271 272 /* lock the device pointers and do the reset */ 273 mutex_lock(&(us->dev_mutex)); 274 result = us->transport_reset(us); 275 mutex_unlock(&us->dev_mutex); 276 277 return result < 0 ? FAILED : SUCCESS; 278 } 279 280 /* Simulate a SCSI bus reset by resetting the device's USB port. */ 281 static int bus_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 result = usb_stor_port_reset(us); 288 return result < 0 ? FAILED : SUCCESS; 289 } 290 291 /* Report a driver-initiated device reset to the SCSI layer. 292 * Calling this for a SCSI-initiated reset is unnecessary but harmless. 293 * The caller must own the SCSI host lock. */ 294 void usb_stor_report_device_reset(struct us_data *us) 295 { 296 int i; 297 struct Scsi_Host *host = us_to_host(us); 298 299 scsi_report_device_reset(host, 0, 0); 300 if (us->flags & US_FL_SCM_MULT_TARG) { 301 for (i = 1; i < host->max_id; ++i) 302 scsi_report_device_reset(host, 0, i); 303 } 304 } 305 306 /* Report a driver-initiated bus reset to the SCSI layer. 307 * Calling this for a SCSI-initiated reset is unnecessary but harmless. 308 * The caller must own the SCSI host lock. */ 309 void usb_stor_report_bus_reset(struct us_data *us) 310 { 311 scsi_report_bus_reset(us_to_host(us), 0); 312 } 313 314 /*********************************************************************** 315 * /proc/scsi/ functions 316 ***********************************************************************/ 317 318 /* we use this macro to help us write into the buffer */ 319 #undef SPRINTF 320 #define SPRINTF(args...) \ 321 do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0) 322 323 static int proc_info (struct Scsi_Host *host, char *buffer, 324 char **start, off_t offset, int length, int inout) 325 { 326 struct us_data *us = host_to_us(host); 327 char *pos = buffer; 328 const char *string; 329 330 /* if someone is sending us data, just throw it away */ 331 if (inout) 332 return length; 333 334 /* print the controller name */ 335 SPRINTF(" Host scsi%d: usb-storage\n", host->host_no); 336 337 /* print product, vendor, and serial number strings */ 338 if (us->pusb_dev->manufacturer) 339 string = us->pusb_dev->manufacturer; 340 else if (us->unusual_dev->vendorName) 341 string = us->unusual_dev->vendorName; 342 else 343 string = "Unknown"; 344 SPRINTF(" Vendor: %s\n", string); 345 if (us->pusb_dev->product) 346 string = us->pusb_dev->product; 347 else if (us->unusual_dev->productName) 348 string = us->unusual_dev->productName; 349 else 350 string = "Unknown"; 351 SPRINTF(" Product: %s\n", string); 352 if (us->pusb_dev->serial) 353 string = us->pusb_dev->serial; 354 else 355 string = "None"; 356 SPRINTF("Serial Number: %s\n", string); 357 358 /* show the protocol and transport */ 359 SPRINTF(" Protocol: %s\n", us->protocol_name); 360 SPRINTF(" Transport: %s\n", us->transport_name); 361 362 /* show the device flags */ 363 if (pos < buffer + length) { 364 pos += sprintf(pos, " Quirks:"); 365 366 #define US_FLAG(name, value) \ 367 if (us->flags & value) pos += sprintf(pos, " " #name); 368 US_DO_ALL_FLAGS 369 #undef US_FLAG 370 371 *(pos++) = '\n'; 372 } 373 374 /* 375 * Calculate start of next buffer, and return value. 376 */ 377 *start = buffer + offset; 378 379 if ((pos - buffer) < offset) 380 return (0); 381 else if ((pos - buffer - offset) < length) 382 return (pos - buffer - offset); 383 else 384 return (length); 385 } 386 387 /*********************************************************************** 388 * Sysfs interface 389 ***********************************************************************/ 390 391 /* Output routine for the sysfs max_sectors file */ 392 static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf) 393 { 394 struct scsi_device *sdev = to_scsi_device(dev); 395 396 return sprintf(buf, "%u\n", sdev->request_queue->max_sectors); 397 } 398 399 /* Input routine for the sysfs max_sectors file */ 400 static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf, 401 size_t count) 402 { 403 struct scsi_device *sdev = to_scsi_device(dev); 404 unsigned short ms; 405 406 if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) { 407 blk_queue_max_sectors(sdev->request_queue, ms); 408 return strlen(buf); 409 } 410 return -EINVAL; 411 } 412 413 static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors, 414 store_max_sectors); 415 416 static struct device_attribute *sysfs_device_attr_list[] = { 417 &dev_attr_max_sectors, 418 NULL, 419 }; 420 421 /* 422 * this defines our host template, with which we'll allocate hosts 423 */ 424 425 struct scsi_host_template usb_stor_host_template = { 426 /* basic userland interface stuff */ 427 .name = "usb-storage", 428 .proc_name = "usb-storage", 429 .proc_info = proc_info, 430 .info = host_info, 431 432 /* command interface -- queued only */ 433 .queuecommand = queuecommand, 434 435 /* error and abort handlers */ 436 .eh_abort_handler = command_abort, 437 .eh_device_reset_handler = device_reset, 438 .eh_bus_reset_handler = bus_reset, 439 440 /* queue commands only, only one command per LUN */ 441 .can_queue = 1, 442 .cmd_per_lun = 1, 443 444 /* unknown initiator id */ 445 .this_id = -1, 446 447 .slave_alloc = slave_alloc, 448 .slave_configure = slave_configure, 449 450 /* lots of sg segments can be handled */ 451 .sg_tablesize = SG_ALL, 452 453 /* limit the total size of a transfer to 120 KB */ 454 .max_sectors = 240, 455 456 /* merge commands... this seems to help performance, but 457 * periodically someone should test to see which setting is more 458 * optimal. 459 */ 460 .use_clustering = 1, 461 462 /* emulated HBA */ 463 .emulated = 1, 464 465 /* we do our own delay after a device or bus reset */ 466 .skip_settle_delay = 1, 467 468 /* sysfs device attributes */ 469 .sdev_attrs = sysfs_device_attr_list, 470 471 /* module management */ 472 .module = THIS_MODULE 473 }; 474 475 /* To Report "Illegal Request: Invalid Field in CDB */ 476 unsigned char usb_stor_sense_invalidCDB[18] = { 477 [0] = 0x70, /* current error */ 478 [2] = ILLEGAL_REQUEST, /* Illegal Request = 0x05 */ 479 [7] = 0x0a, /* additional length */ 480 [12] = 0x24 /* Invalid Field in CDB */ 481 }; 482 483