scsiglue.c revision 226173edae1c49c68ebb723771a02302c85e3475
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 67static const char* host_info(struct Scsi_Host *host) 68{ 69 return "SCSI emulation for USB Mass Storage devices"; 70} 71 72static 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 83static 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; 158 159 /* Some devices report a SCSI revision level above 2 but are 160 * unable to handle the REPORT LUNS command (for which 161 * support is mandatory at level 3). Since we already have 162 * a Get-Max-LUN request, we won't lose much by setting the 163 * revision level down to 2. The only devices that would be 164 * affected are those with sparse LUNs. */ 165 sdev->scsi_level = SCSI_2; 166 167 /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable 168 * Hardware Error) when any low-level error occurs, 169 * recoverable or not. Setting this flag tells the SCSI 170 * midlayer to retry such commands, which frequently will 171 * succeed and fix the error. The worst this can lead to 172 * is an occasional series of retries that will all fail. */ 173 sdev->retry_hwerror = 1; 174 175 } else { 176 177 /* Non-disk-type devices don't need to blacklist any pages 178 * or to force 192-byte transfer lengths for MODE SENSE. 179 * But they do need to use MODE SENSE(10). */ 180 sdev->use_10_for_ms = 1; 181 } 182 183 /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM 184 * REMOVAL command, so suppress those commands. */ 185 if (us->flags & US_FL_NOT_LOCKABLE) 186 sdev->lockable = 0; 187 188 /* this is to satisfy the compiler, tho I don't think the 189 * return code is ever checked anywhere. */ 190 return 0; 191} 192 193/* queue a command */ 194/* This is always called with scsi_lock(host) held */ 195static int queuecommand(struct scsi_cmnd *srb, 196 void (*done)(struct scsi_cmnd *)) 197{ 198 struct us_data *us = host_to_us(srb->device->host); 199 200 US_DEBUGP("%s called\n", __FUNCTION__); 201 202 /* check for state-transition errors */ 203 if (us->srb != NULL) { 204 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n", 205 __FUNCTION__, us->srb); 206 return SCSI_MLQUEUE_HOST_BUSY; 207 } 208 209 /* fail the command if we are disconnecting */ 210 if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) { 211 US_DEBUGP("Fail command during disconnect\n"); 212 srb->result = DID_NO_CONNECT << 16; 213 done(srb); 214 return 0; 215 } 216 217 /* enqueue the command and wake up the control thread */ 218 srb->scsi_done = done; 219 us->srb = srb; 220 up(&(us->sema)); 221 222 return 0; 223} 224 225/*********************************************************************** 226 * Error handling functions 227 ***********************************************************************/ 228 229/* Command timeout and abort */ 230static int command_abort(struct scsi_cmnd *srb) 231{ 232 struct us_data *us = host_to_us(srb->device->host); 233 234 US_DEBUGP("%s called\n", __FUNCTION__); 235 236 /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING 237 * bits are protected by the host lock. */ 238 scsi_lock(us_to_host(us)); 239 240 /* Is this command still active? */ 241 if (us->srb != srb) { 242 scsi_unlock(us_to_host(us)); 243 US_DEBUGP ("-- nothing to abort\n"); 244 return FAILED; 245 } 246 247 /* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if 248 * a device reset isn't already in progress (to avoid interfering 249 * with the reset). Note that we must retain the host lock while 250 * calling usb_stor_stop_transport(); otherwise it might interfere 251 * with an auto-reset that begins as soon as we release the lock. */ 252 set_bit(US_FLIDX_TIMED_OUT, &us->flags); 253 if (!test_bit(US_FLIDX_RESETTING, &us->flags)) { 254 set_bit(US_FLIDX_ABORTING, &us->flags); 255 usb_stor_stop_transport(us); 256 } 257 scsi_unlock(us_to_host(us)); 258 259 /* Wait for the aborted command to finish */ 260 wait_for_completion(&us->notify); 261 return SUCCESS; 262} 263 264/* This invokes the transport reset mechanism to reset the state of the 265 * device */ 266static int device_reset(struct scsi_cmnd *srb) 267{ 268 struct us_data *us = host_to_us(srb->device->host); 269 int result; 270 271 US_DEBUGP("%s called\n", __FUNCTION__); 272 273 /* lock the device pointers and do the reset */ 274 down(&(us->dev_semaphore)); 275 result = us->transport_reset(us); 276 up(&(us->dev_semaphore)); 277 278 return result < 0 ? FAILED : SUCCESS; 279} 280 281/* Simulate a SCSI bus reset by resetting the device's USB port. */ 282static int bus_reset(struct scsi_cmnd *srb) 283{ 284 struct us_data *us = host_to_us(srb->device->host); 285 int result; 286 287 US_DEBUGP("%s called\n", __FUNCTION__); 288 289 down(&(us->dev_semaphore)); 290 result = usb_stor_port_reset(us); 291 up(&(us->dev_semaphore)); 292 293 return result < 0 ? FAILED : SUCCESS; 294} 295 296/* Report a driver-initiated device reset to the SCSI layer. 297 * Calling this for a SCSI-initiated reset is unnecessary but harmless. 298 * The caller must own the SCSI host lock. */ 299void usb_stor_report_device_reset(struct us_data *us) 300{ 301 int i; 302 struct Scsi_Host *host = us_to_host(us); 303 304 scsi_report_device_reset(host, 0, 0); 305 if (us->flags & US_FL_SCM_MULT_TARG) { 306 for (i = 1; i < host->max_id; ++i) 307 scsi_report_device_reset(host, 0, i); 308 } 309} 310 311/* Report a driver-initiated bus 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. */ 314void usb_stor_report_bus_reset(struct us_data *us) 315{ 316 scsi_report_bus_reset(us_to_host(us), 0); 317} 318 319/*********************************************************************** 320 * /proc/scsi/ functions 321 ***********************************************************************/ 322 323/* we use this macro to help us write into the buffer */ 324#undef SPRINTF 325#define SPRINTF(args...) \ 326 do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0) 327 328static int proc_info (struct Scsi_Host *host, char *buffer, 329 char **start, off_t offset, int length, int inout) 330{ 331 struct us_data *us = host_to_us(host); 332 char *pos = buffer; 333 const char *string; 334 335 /* if someone is sending us data, just throw it away */ 336 if (inout) 337 return length; 338 339 /* print the controller name */ 340 SPRINTF(" Host scsi%d: usb-storage\n", host->host_no); 341 342 /* print product, vendor, and serial number strings */ 343 if (us->pusb_dev->manufacturer) 344 string = us->pusb_dev->manufacturer; 345 else if (us->unusual_dev->vendorName) 346 string = us->unusual_dev->vendorName; 347 else 348 string = "Unknown"; 349 SPRINTF(" Vendor: %s\n", string); 350 if (us->pusb_dev->product) 351 string = us->pusb_dev->product; 352 else if (us->unusual_dev->productName) 353 string = us->unusual_dev->productName; 354 else 355 string = "Unknown"; 356 SPRINTF(" Product: %s\n", string); 357 if (us->pusb_dev->serial) 358 string = us->pusb_dev->serial; 359 else 360 string = "None"; 361 SPRINTF("Serial Number: %s\n", string); 362 363 /* show the protocol and transport */ 364 SPRINTF(" Protocol: %s\n", us->protocol_name); 365 SPRINTF(" Transport: %s\n", us->transport_name); 366 367 /* show the device flags */ 368 if (pos < buffer + length) { 369 pos += sprintf(pos, " Quirks:"); 370 371#define US_FLAG(name, value) \ 372 if (us->flags & value) pos += sprintf(pos, " " #name); 373US_DO_ALL_FLAGS 374#undef US_FLAG 375 376 *(pos++) = '\n'; 377 } 378 379 /* 380 * Calculate start of next buffer, and return value. 381 */ 382 *start = buffer + offset; 383 384 if ((pos - buffer) < offset) 385 return (0); 386 else if ((pos - buffer - offset) < length) 387 return (pos - buffer - offset); 388 else 389 return (length); 390} 391 392/*********************************************************************** 393 * Sysfs interface 394 ***********************************************************************/ 395 396/* Output routine for the sysfs max_sectors file */ 397static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf) 398{ 399 struct scsi_device *sdev = to_scsi_device(dev); 400 401 return sprintf(buf, "%u\n", sdev->request_queue->max_sectors); 402} 403 404/* Input routine for the sysfs max_sectors file */ 405static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf, 406 size_t count) 407{ 408 struct scsi_device *sdev = to_scsi_device(dev); 409 unsigned short ms; 410 411 if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) { 412 blk_queue_max_sectors(sdev->request_queue, ms); 413 return strlen(buf); 414 } 415 return -EINVAL; 416} 417 418static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors, 419 store_max_sectors); 420 421static struct device_attribute *sysfs_device_attr_list[] = { 422 &dev_attr_max_sectors, 423 NULL, 424 }; 425 426/* 427 * this defines our host template, with which we'll allocate hosts 428 */ 429 430struct scsi_host_template usb_stor_host_template = { 431 /* basic userland interface stuff */ 432 .name = "usb-storage", 433 .proc_name = "usb-storage", 434 .proc_info = proc_info, 435 .info = host_info, 436 437 /* command interface -- queued only */ 438 .queuecommand = queuecommand, 439 440 /* error and abort handlers */ 441 .eh_abort_handler = command_abort, 442 .eh_device_reset_handler = device_reset, 443 .eh_bus_reset_handler = bus_reset, 444 445 /* queue commands only, only one command per LUN */ 446 .can_queue = 1, 447 .cmd_per_lun = 1, 448 449 /* unknown initiator id */ 450 .this_id = -1, 451 452 .slave_alloc = slave_alloc, 453 .slave_configure = slave_configure, 454 455 /* lots of sg segments can be handled */ 456 .sg_tablesize = SG_ALL, 457 458 /* limit the total size of a transfer to 120 KB */ 459 .max_sectors = 240, 460 461 /* merge commands... this seems to help performance, but 462 * periodically someone should test to see which setting is more 463 * optimal. 464 */ 465 .use_clustering = 1, 466 467 /* emulated HBA */ 468 .emulated = 1, 469 470 /* we do our own delay after a device or bus reset */ 471 .skip_settle_delay = 1, 472 473 /* sysfs device attributes */ 474 .sdev_attrs = sysfs_device_attr_list, 475 476 /* module management */ 477 .module = THIS_MODULE 478}; 479 480/* To Report "Illegal Request: Invalid Field in CDB */ 481unsigned char usb_stor_sense_invalidCDB[18] = { 482 [0] = 0x70, /* current error */ 483 [2] = ILLEGAL_REQUEST, /* Illegal Request = 0x05 */ 484 [7] = 0x0a, /* additional length */ 485 [12] = 0x24 /* Invalid Field in CDB */ 486}; 487 488