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 /* According to the technical support people at Genesys Logic, 116 * devices using their chips have problems transferring more than 117 * 32 KB at a time. In practice people have found that 64 KB 118 * works okay and that's what Windows does. But we'll be 119 * conservative; people can always use the sysfs interface to 120 * increase max_sectors. */ 121 if (le16_to_cpu(us->pusb_dev->descriptor.idVendor) == USB_VENDOR_ID_GENESYS && 122 sdev->request_queue->max_sectors > 64) 123 blk_queue_max_sectors(sdev->request_queue, 64); 124 125 /* We can't put these settings in slave_alloc() because that gets 126 * called before the device type is known. Consequently these 127 * settings can't be overridden via the scsi devinfo mechanism. */ 128 if (sdev->type == TYPE_DISK) { 129 130 /* Disk-type devices use MODE SENSE(6) if the protocol 131 * (SubClass) is Transparent SCSI, otherwise they use 132 * MODE SENSE(10). */ 133 if (us->subclass != US_SC_SCSI) 134 sdev->use_10_for_ms = 1; 135 136 /* Many disks only accept MODE SENSE transfer lengths of 137 * 192 bytes (that's what Windows uses). */ 138 sdev->use_192_bytes_for_3f = 1; 139 140 /* Some devices don't like MODE SENSE with page=0x3f, 141 * which is the command used for checking if a device 142 * is write-protected. Now that we tell the sd driver 143 * to do a 192-byte transfer with this command the 144 * majority of devices work fine, but a few still can't 145 * handle it. The sd driver will simply assume those 146 * devices are write-enabled. */ 147 if (us->flags & US_FL_NO_WP_DETECT) 148 sdev->skip_ms_page_3f = 1; 149 150 /* A number of devices have problems with MODE SENSE for 151 * page x08, so we will skip it. */ 152 sdev->skip_ms_page_8 = 1; 153 154 /* Some disks return the total number of blocks in response 155 * to READ CAPACITY rather than the highest block number. 156 * If this device makes that mistake, tell the sd driver. */ 157 if (us->flags & US_FL_FIX_CAPACITY) 158 sdev->fix_capacity = 1; 159 160 /* Some devices report a SCSI revision level above 2 but are 161 * unable to handle the REPORT LUNS command (for which 162 * support is mandatory at level 3). Since we already have 163 * a Get-Max-LUN request, we won't lose much by setting the 164 * revision level down to 2. The only devices that would be 165 * affected are those with sparse LUNs. */ 166 sdev->scsi_level = sdev->sdev_target->scsi_level = SCSI_2; 167 168 /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable 169 * Hardware Error) when any low-level error occurs, 170 * recoverable or not. Setting this flag tells the SCSI 171 * midlayer to retry such commands, which frequently will 172 * succeed and fix the error. The worst this can lead to 173 * is an occasional series of retries that will all fail. */ 174 sdev->retry_hwerror = 1; 175 176 } else { 177 178 /* Non-disk-type devices don't need to blacklist any pages 179 * or to force 192-byte transfer lengths for MODE SENSE. 180 * But they do need to use MODE SENSE(10). */ 181 sdev->use_10_for_ms = 1; 182 } 183 184 /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM 185 * REMOVAL command, so suppress those commands. */ 186 if (us->flags & US_FL_NOT_LOCKABLE) 187 sdev->lockable = 0; 188 189 /* this is to satisfy the compiler, tho I don't think the 190 * return code is ever checked anywhere. */ 191 return 0; 192 } 193 194 /* queue a command */ 195 /* This is always called with scsi_lock(host) held */ 196 static int queuecommand(struct scsi_cmnd *srb, 197 void (*done)(struct scsi_cmnd *)) 198 { 199 struct us_data *us = host_to_us(srb->device->host); 200 201 US_DEBUGP("%s called\n", __FUNCTION__); 202 203 /* check for state-transition errors */ 204 if (us->srb != NULL) { 205 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n", 206 __FUNCTION__, us->srb); 207 return SCSI_MLQUEUE_HOST_BUSY; 208 } 209 210 /* fail the command if we are disconnecting */ 211 if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) { 212 US_DEBUGP("Fail command during disconnect\n"); 213 srb->result = DID_NO_CONNECT << 16; 214 done(srb); 215 return 0; 216 } 217 218 /* enqueue the command and wake up the control thread */ 219 srb->scsi_done = done; 220 us->srb = srb; 221 up(&(us->sema)); 222 223 return 0; 224 } 225 226 /*********************************************************************** 227 * Error handling functions 228 ***********************************************************************/ 229 230 /* Command timeout and abort */ 231 static int command_abort(struct scsi_cmnd *srb) 232 { 233 struct us_data *us = host_to_us(srb->device->host); 234 235 US_DEBUGP("%s called\n", __FUNCTION__); 236 237 /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING 238 * bits are protected by the host lock. */ 239 scsi_lock(us_to_host(us)); 240 241 /* Is this command still active? */ 242 if (us->srb != srb) { 243 scsi_unlock(us_to_host(us)); 244 US_DEBUGP ("-- nothing to abort\n"); 245 return FAILED; 246 } 247 248 /* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if 249 * a device reset isn't already in progress (to avoid interfering 250 * with the reset). Note that we must retain the host lock while 251 * calling usb_stor_stop_transport(); otherwise it might interfere 252 * with an auto-reset that begins as soon as we release the lock. */ 253 set_bit(US_FLIDX_TIMED_OUT, &us->flags); 254 if (!test_bit(US_FLIDX_RESETTING, &us->flags)) { 255 set_bit(US_FLIDX_ABORTING, &us->flags); 256 usb_stor_stop_transport(us); 257 } 258 scsi_unlock(us_to_host(us)); 259 260 /* Wait for the aborted command to finish */ 261 wait_for_completion(&us->notify); 262 return SUCCESS; 263 } 264 265 /* This invokes the transport reset mechanism to reset the state of the 266 * device */ 267 static int device_reset(struct scsi_cmnd *srb) 268 { 269 struct us_data *us = host_to_us(srb->device->host); 270 int result; 271 272 US_DEBUGP("%s called\n", __FUNCTION__); 273 274 /* lock the device pointers and do the reset */ 275 mutex_lock(&(us->dev_mutex)); 276 result = us->transport_reset(us); 277 mutex_unlock(&us->dev_mutex); 278 279 return result < 0 ? FAILED : SUCCESS; 280 } 281 282 /* Simulate a SCSI bus reset by resetting the device's USB port. */ 283 static int bus_reset(struct scsi_cmnd *srb) 284 { 285 struct us_data *us = host_to_us(srb->device->host); 286 int result; 287 288 US_DEBUGP("%s called\n", __FUNCTION__); 289 290 mutex_lock(&(us->dev_mutex)); 291 result = usb_stor_port_reset(us); 292 mutex_unlock(&us->dev_mutex); 293 294 return result < 0 ? FAILED : SUCCESS; 295 } 296 297 /* Report a driver-initiated device reset to the SCSI layer. 298 * Calling this for a SCSI-initiated reset is unnecessary but harmless. 299 * The caller must own the SCSI host lock. */ 300 void usb_stor_report_device_reset(struct us_data *us) 301 { 302 int i; 303 struct Scsi_Host *host = us_to_host(us); 304 305 scsi_report_device_reset(host, 0, 0); 306 if (us->flags & US_FL_SCM_MULT_TARG) { 307 for (i = 1; i < host->max_id; ++i) 308 scsi_report_device_reset(host, 0, i); 309 } 310 } 311 312 /* Report a driver-initiated bus reset to the SCSI layer. 313 * Calling this for a SCSI-initiated reset is unnecessary but harmless. 314 * The caller must own the SCSI host lock. */ 315 void usb_stor_report_bus_reset(struct us_data *us) 316 { 317 scsi_report_bus_reset(us_to_host(us), 0); 318 } 319 320 /*********************************************************************** 321 * /proc/scsi/ functions 322 ***********************************************************************/ 323 324 /* we use this macro to help us write into the buffer */ 325 #undef SPRINTF 326 #define SPRINTF(args...) \ 327 do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0) 328 329 static int proc_info (struct Scsi_Host *host, char *buffer, 330 char **start, off_t offset, int length, int inout) 331 { 332 struct us_data *us = host_to_us(host); 333 char *pos = buffer; 334 const char *string; 335 336 /* if someone is sending us data, just throw it away */ 337 if (inout) 338 return length; 339 340 /* print the controller name */ 341 SPRINTF(" Host scsi%d: usb-storage\n", host->host_no); 342 343 /* print product, vendor, and serial number strings */ 344 if (us->pusb_dev->manufacturer) 345 string = us->pusb_dev->manufacturer; 346 else if (us->unusual_dev->vendorName) 347 string = us->unusual_dev->vendorName; 348 else 349 string = "Unknown"; 350 SPRINTF(" Vendor: %s\n", string); 351 if (us->pusb_dev->product) 352 string = us->pusb_dev->product; 353 else if (us->unusual_dev->productName) 354 string = us->unusual_dev->productName; 355 else 356 string = "Unknown"; 357 SPRINTF(" Product: %s\n", string); 358 if (us->pusb_dev->serial) 359 string = us->pusb_dev->serial; 360 else 361 string = "None"; 362 SPRINTF("Serial Number: %s\n", string); 363 364 /* show the protocol and transport */ 365 SPRINTF(" Protocol: %s\n", us->protocol_name); 366 SPRINTF(" Transport: %s\n", us->transport_name); 367 368 /* show the device flags */ 369 if (pos < buffer + length) { 370 pos += sprintf(pos, " Quirks:"); 371 372 #define US_FLAG(name, value) \ 373 if (us->flags & value) pos += sprintf(pos, " " #name); 374 US_DO_ALL_FLAGS 375 #undef US_FLAG 376 377 *(pos++) = '\n'; 378 } 379 380 /* 381 * Calculate start of next buffer, and return value. 382 */ 383 *start = buffer + offset; 384 385 if ((pos - buffer) < offset) 386 return (0); 387 else if ((pos - buffer - offset) < length) 388 return (pos - buffer - offset); 389 else 390 return (length); 391 } 392 393 /*********************************************************************** 394 * Sysfs interface 395 ***********************************************************************/ 396 397 /* Output routine for the sysfs max_sectors file */ 398 static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf) 399 { 400 struct scsi_device *sdev = to_scsi_device(dev); 401 402 return sprintf(buf, "%u\n", sdev->request_queue->max_sectors); 403 } 404 405 /* Input routine for the sysfs max_sectors file */ 406 static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf, 407 size_t count) 408 { 409 struct scsi_device *sdev = to_scsi_device(dev); 410 unsigned short ms; 411 412 if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) { 413 blk_queue_max_sectors(sdev->request_queue, ms); 414 return strlen(buf); 415 } 416 return -EINVAL; 417 } 418 419 static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors, 420 store_max_sectors); 421 422 static struct device_attribute *sysfs_device_attr_list[] = { 423 &dev_attr_max_sectors, 424 NULL, 425 }; 426 427 /* 428 * this defines our host template, with which we'll allocate hosts 429 */ 430 431 struct scsi_host_template usb_stor_host_template = { 432 /* basic userland interface stuff */ 433 .name = "usb-storage", 434 .proc_name = "usb-storage", 435 .proc_info = proc_info, 436 .info = host_info, 437 438 /* command interface -- queued only */ 439 .queuecommand = queuecommand, 440 441 /* error and abort handlers */ 442 .eh_abort_handler = command_abort, 443 .eh_device_reset_handler = device_reset, 444 .eh_bus_reset_handler = bus_reset, 445 446 /* queue commands only, only one command per LUN */ 447 .can_queue = 1, 448 .cmd_per_lun = 1, 449 450 /* unknown initiator id */ 451 .this_id = -1, 452 453 .slave_alloc = slave_alloc, 454 .slave_configure = slave_configure, 455 456 /* lots of sg segments can be handled */ 457 .sg_tablesize = SG_ALL, 458 459 /* limit the total size of a transfer to 120 KB */ 460 .max_sectors = 240, 461 462 /* merge commands... this seems to help performance, but 463 * periodically someone should test to see which setting is more 464 * optimal. 465 */ 466 .use_clustering = 1, 467 468 /* emulated HBA */ 469 .emulated = 1, 470 471 /* we do our own delay after a device or bus reset */ 472 .skip_settle_delay = 1, 473 474 /* sysfs device attributes */ 475 .sdev_attrs = sysfs_device_attr_list, 476 477 /* module management */ 478 .module = THIS_MODULE 479 }; 480 481 /* To Report "Illegal Request: Invalid Field in CDB */ 482 unsigned char usb_stor_sense_invalidCDB[18] = { 483 [0] = 0x70, /* current error */ 484 [2] = ILLEGAL_REQUEST, /* Illegal Request = 0x05 */ 485 [7] = 0x0a, /* additional length */ 486 [12] = 0x24 /* Invalid Field in CDB */ 487 }; 488 489