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
77 /*
78 * Set the INQUIRY transfer length to 36. We don't use any of
79 * the extra data and many devices choke if asked for more or
80 * less than 36 bytes.
81 */
82 sdev->inquiry_len = 36;
83
84 /* Scatter-gather buffers (all but the last) must have a length
85 * divisible by the bulk maxpacket size. Otherwise a data packet
86 * would end up being short, causing a premature end to the data
87 * transfer. Since high-speed bulk pipes have a maxpacket size
88 * of 512, we'll use that as the scsi device queue's DMA alignment
89 * mask. Guaranteeing proper alignment of the first buffer will
90 * have the desired effect because, except at the beginning and
91 * the end, scatter-gather buffers follow page boundaries. */
92 blk_queue_update_dma_alignment(sdev->request_queue, (512 - 1));
93
94 /*
95 * The UFI spec treates the Peripheral Qualifier bits in an
96 * INQUIRY result as reserved and requires devices to set them
97 * to 0. However the SCSI spec requires these bits to be set
98 * to 3 to indicate when a LUN is not present.
99 *
100 * Let the scanning code know if this target merely sets
101 * Peripheral Device Type to 0x1f to indicate no LUN.
102 */
103 if (us->subclass == US_SC_UFI)
104 sdev->sdev_target->pdt_1f_for_no_lun = 1;
105
106 return 0;
107 }
108
109 static int slave_configure(struct scsi_device *sdev)
110 {
111 struct us_data *us = host_to_us(sdev->host);
112
113 /* Many devices have trouble transfering more than 32KB at a time,
114 * while others have trouble with more than 64K. At this time we
115 * are limiting both to 32K (64 sectores).
116 */
117 if (us->flags & (US_FL_MAX_SECTORS_64 | US_FL_MAX_SECTORS_MIN)) {
118 unsigned int max_sectors = 64;
119
120 if (us->flags & US_FL_MAX_SECTORS_MIN)
121 max_sectors = PAGE_CACHE_SIZE >> 9;
122 if (sdev->request_queue->max_sectors > max_sectors)
123 blk_queue_max_sectors(sdev->request_queue,
124 max_sectors);
125 }
126
127 /* We can't put these settings in slave_alloc() because that gets
128 * called before the device type is known. Consequently these
129 * settings can't be overridden via the scsi devinfo mechanism. */
130 if (sdev->type == TYPE_DISK) {
131
132 /* Disk-type devices use MODE SENSE(6) if the protocol
133 * (SubClass) is Transparent SCSI, otherwise they use
134 * MODE SENSE(10). */
135 if (us->subclass != US_SC_SCSI)
136 sdev->use_10_for_ms = 1;
137
138 /* Many disks only accept MODE SENSE transfer lengths of
139 * 192 bytes (that's what Windows uses). */
140 sdev->use_192_bytes_for_3f = 1;
141
142 /* Some devices don't like MODE SENSE with page=0x3f,
143 * which is the command used for checking if a device
144 * is write-protected. Now that we tell the sd driver
145 * to do a 192-byte transfer with this command the
146 * majority of devices work fine, but a few still can't
147 * handle it. The sd driver will simply assume those
148 * devices are write-enabled. */
149 if (us->flags & US_FL_NO_WP_DETECT)
150 sdev->skip_ms_page_3f = 1;
151
152 /* A number of devices have problems with MODE SENSE for
153 * page x08, so we will skip it. */
154 sdev->skip_ms_page_8 = 1;
155
156 /* Some disks return the total number of blocks in response
157 * to READ CAPACITY rather than the highest block number.
158 * If this device makes that mistake, tell the sd driver. */
159 if (us->flags & US_FL_FIX_CAPACITY)
160 sdev->fix_capacity = 1;
161
162 /* A few disks have two indistinguishable version, one of
163 * which reports the correct capacity and the other does not.
164 * The sd driver has to guess which is the case. */
165 if (us->flags & US_FL_CAPACITY_HEURISTICS)
166 sdev->guess_capacity = 1;
167
168 /* Some devices report a SCSI revision level above 2 but are
169 * unable to handle the REPORT LUNS command (for which
170 * support is mandatory at level 3). Since we already have
171 * a Get-Max-LUN request, we won't lose much by setting the
172 * revision level down to 2. The only devices that would be
173 * affected are those with sparse LUNs. */
174 if (sdev->scsi_level > SCSI_2)
175 sdev->sdev_target->scsi_level =
176 sdev->scsi_level = SCSI_2;
177
178 /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
179 * Hardware Error) when any low-level error occurs,
180 * recoverable or not. Setting this flag tells the SCSI
181 * midlayer to retry such commands, which frequently will
182 * succeed and fix the error. The worst this can lead to
183 * is an occasional series of retries that will all fail. */
184 sdev->retry_hwerror = 1;
185
186 /* USB disks should allow restart. Some drives spin down
187 * automatically, requiring a START-STOP UNIT command. */
188 sdev->allow_restart = 1;
189
190 /* Some USB cardreaders have trouble reading an sdcard's last
191 * sector in a larger then 1 sector read, since the performance
192 * impact is negible we set this flag for all USB disks */
193 sdev->last_sector_bug = 1;
194 } else {
195
196 /* Non-disk-type devices don't need to blacklist any pages
197 * or to force 192-byte transfer lengths for MODE SENSE.
198 * But they do need to use MODE SENSE(10). */
199 sdev->use_10_for_ms = 1;
200 }
201
202 /* The CB and CBI transports have no way to pass LUN values
203 * other than the bits in the second byte of a CDB. But those
204 * bits don't get set to the LUN value if the device reports
205 * scsi_level == 0 (UNKNOWN). Hence such devices must necessarily
206 * be single-LUN.
207 */
208 if ((us->protocol == US_PR_CB || us->protocol == US_PR_CBI) &&
209 sdev->scsi_level == SCSI_UNKNOWN)
210 us->max_lun = 0;
211
212 /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
213 * REMOVAL command, so suppress those commands. */
214 if (us->flags & US_FL_NOT_LOCKABLE)
215 sdev->lockable = 0;
216
217 /* this is to satisfy the compiler, tho I don't think the
218 * return code is ever checked anywhere. */
219 return 0;
220 }
221
222 /* queue a command */
223 /* This is always called with scsi_lock(host) held */
224 static int queuecommand(struct scsi_cmnd *srb,
225 void (*done)(struct scsi_cmnd *))
226 {
227 struct us_data *us = host_to_us(srb->device->host);
228
229 US_DEBUGP("%s called\n", __FUNCTION__);
230
231 /* check for state-transition errors */
232 if (us->srb != NULL) {
233 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n",
234 __FUNCTION__, us->srb);
235 return SCSI_MLQUEUE_HOST_BUSY;
236 }
237
238 /* fail the command if we are disconnecting */
239 if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) {
240 US_DEBUGP("Fail command during disconnect\n");
241 srb->result = DID_NO_CONNECT << 16;
242 done(srb);
243 return 0;
244 }
245
246 /* enqueue the command and wake up the control thread */
247 srb->scsi_done = done;
248 us->srb = srb;
249 up(&(us->sema));
250
251 return 0;
252 }
253
254 /***********************************************************************
255 * Error handling functions
256 ***********************************************************************/
257
258 /* Command timeout and abort */
259 static int command_abort(struct scsi_cmnd *srb)
260 {
261 struct us_data *us = host_to_us(srb->device->host);
262
263 US_DEBUGP("%s called\n", __FUNCTION__);
264
265 /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
266 * bits are protected by the host lock. */
267 scsi_lock(us_to_host(us));
268
269 /* Is this command still active? */
270 if (us->srb != srb) {
271 scsi_unlock(us_to_host(us));
272 US_DEBUGP ("-- nothing to abort\n");
273 return FAILED;
274 }
275
276 /* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if
277 * a device reset isn't already in progress (to avoid interfering
278 * with the reset). Note that we must retain the host lock while
279 * calling usb_stor_stop_transport(); otherwise it might interfere
280 * with an auto-reset that begins as soon as we release the lock. */
281 set_bit(US_FLIDX_TIMED_OUT, &us->flags);
282 if (!test_bit(US_FLIDX_RESETTING, &us->flags)) {
283 set_bit(US_FLIDX_ABORTING, &us->flags);
284 usb_stor_stop_transport(us);
285 }
286 scsi_unlock(us_to_host(us));
287
288 /* Wait for the aborted command to finish */
289 wait_for_completion(&us->notify);
290 return SUCCESS;
291 }
292
293 /* This invokes the transport reset mechanism to reset the state of the
294 * device */
295 static int device_reset(struct scsi_cmnd *srb)
296 {
297 struct us_data *us = host_to_us(srb->device->host);
298 int result;
299
300 US_DEBUGP("%s called\n", __FUNCTION__);
301
302 /* lock the device pointers and do the reset */
303 mutex_lock(&(us->dev_mutex));
304 result = us->transport_reset(us);
305 mutex_unlock(&us->dev_mutex);
306
307 return result < 0 ? FAILED : SUCCESS;
308 }
309
310 /* Simulate a SCSI bus reset by resetting the device's USB port. */
311 static int bus_reset(struct scsi_cmnd *srb)
312 {
313 struct us_data *us = host_to_us(srb->device->host);
314 int result;
315
316 US_DEBUGP("%s called\n", __FUNCTION__);
317 result = usb_stor_port_reset(us);
318 return result < 0 ? FAILED : SUCCESS;
319 }
320
321 /* Report a driver-initiated device reset to the SCSI layer.
322 * Calling this for a SCSI-initiated reset is unnecessary but harmless.
323 * The caller must own the SCSI host lock. */
324 void usb_stor_report_device_reset(struct us_data *us)
325 {
326 int i;
327 struct Scsi_Host *host = us_to_host(us);
328
329 scsi_report_device_reset(host, 0, 0);
330 if (us->flags & US_FL_SCM_MULT_TARG) {
331 for (i = 1; i < host->max_id; ++i)
332 scsi_report_device_reset(host, 0, i);
333 }
334 }
335
336 /* Report a driver-initiated bus reset to the SCSI layer.
337 * Calling this for a SCSI-initiated reset is unnecessary but harmless.
338 * The caller must not own the SCSI host lock. */
339 void usb_stor_report_bus_reset(struct us_data *us)
340 {
341 struct Scsi_Host *host = us_to_host(us);
342
343 scsi_lock(host);
344 scsi_report_bus_reset(host, 0);
345 scsi_unlock(host);
346 }
347
348 /***********************************************************************
349 * /proc/scsi/ functions
350 ***********************************************************************/
351
352 /* we use this macro to help us write into the buffer */
353 #undef SPRINTF
354 #define SPRINTF(args...) \
355 do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)
356
357 static int proc_info (struct Scsi_Host *host, char *buffer,
358 char **start, off_t offset, int length, int inout)
359 {
360 struct us_data *us = host_to_us(host);
361 char *pos = buffer;
362 const char *string;
363
364 /* if someone is sending us data, just throw it away */
365 if (inout)
366 return length;
367
368 /* print the controller name */
369 SPRINTF(" Host scsi%d: usb-storage\n", host->host_no);
370
371 /* print product, vendor, and serial number strings */
372 if (us->pusb_dev->manufacturer)
373 string = us->pusb_dev->manufacturer;
374 else if (us->unusual_dev->vendorName)
375 string = us->unusual_dev->vendorName;
376 else
377 string = "Unknown";
378 SPRINTF(" Vendor: %s\n", string);
379 if (us->pusb_dev->product)
380 string = us->pusb_dev->product;
381 else if (us->unusual_dev->productName)
382 string = us->unusual_dev->productName;
383 else
384 string = "Unknown";
385 SPRINTF(" Product: %s\n", string);
386 if (us->pusb_dev->serial)
387 string = us->pusb_dev->serial;
388 else
389 string = "None";
390 SPRINTF("Serial Number: %s\n", string);
391
392 /* show the protocol and transport */
393 SPRINTF(" Protocol: %s\n", us->protocol_name);
394 SPRINTF(" Transport: %s\n", us->transport_name);
395
396 /* show the device flags */
397 if (pos < buffer + length) {
398 pos += sprintf(pos, " Quirks:");
399
400 #define US_FLAG(name, value) \
401 if (us->flags & value) pos += sprintf(pos, " " #name);
402 US_DO_ALL_FLAGS
403 #undef US_FLAG
404
405 *(pos++) = '\n';
406 }
407
408 /*
409 * Calculate start of next buffer, and return value.
410 */
411 *start = buffer + offset;
412
413 if ((pos - buffer) < offset)
414 return (0);
415 else if ((pos - buffer - offset) < length)
416 return (pos - buffer - offset);
417 else
418 return (length);
419 }
420
421 /***********************************************************************
422 * Sysfs interface
423 ***********************************************************************/
424
425 /* Output routine for the sysfs max_sectors file */
426 static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf)
427 {
428 struct scsi_device *sdev = to_scsi_device(dev);
429
430 return sprintf(buf, "%u\n", sdev->request_queue->max_sectors);
431 }
432
433 /* Input routine for the sysfs max_sectors file */
434 static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf,
435 size_t count)
436 {
437 struct scsi_device *sdev = to_scsi_device(dev);
438 unsigned short ms;
439
440 if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) {
441 blk_queue_max_sectors(sdev->request_queue, ms);
442 return strlen(buf);
443 }
444 return -EINVAL;
445 }
446
447 static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors,
448 store_max_sectors);
449
450 static struct device_attribute *sysfs_device_attr_list[] = {
451 &dev_attr_max_sectors,
452 NULL,
453 };
454
455 /*
456 * this defines our host template, with which we'll allocate hosts
457 */
458
459 struct scsi_host_template usb_stor_host_template = {
460 /* basic userland interface stuff */
461 .name = "usb-storage",
462 .proc_name = "usb-storage",
463 .proc_info = proc_info,
464 .info = host_info,
465
466 /* command interface -- queued only */
467 .queuecommand = queuecommand,
468
469 /* error and abort handlers */
470 .eh_abort_handler = command_abort,
471 .eh_device_reset_handler = device_reset,
472 .eh_bus_reset_handler = bus_reset,
473
474 /* queue commands only, only one command per LUN */
475 .can_queue = 1,
476 .cmd_per_lun = 1,
477
478 /* unknown initiator id */
479 .this_id = -1,
480
481 .slave_alloc = slave_alloc,
482 .slave_configure = slave_configure,
483
484 /* lots of sg segments can be handled */
485 .sg_tablesize = SG_ALL,
486
487 /* limit the total size of a transfer to 120 KB */
488 .max_sectors = 240,
489
490 /* merge commands... this seems to help performance, but
491 * periodically someone should test to see which setting is more
492 * optimal.
493 */
494 .use_clustering = 1,
495
496 /* emulated HBA */
497 .emulated = 1,
498
499 /* we do our own delay after a device or bus reset */
500 .skip_settle_delay = 1,
501
502 /* sysfs device attributes */
503 .sdev_attrs = sysfs_device_attr_list,
504
505 /* module management */
506 .module = THIS_MODULE
507 };
508
509 /* To Report "Illegal Request: Invalid Field in CDB */
510 unsigned char usb_stor_sense_invalidCDB[18] = {
511 [0] = 0x70, /* current error */
512 [2] = ILLEGAL_REQUEST, /* Illegal Request = 0x05 */
513 [7] = 0x0a, /* additional length */
514 [12] = 0x24 /* Invalid Field in CDB */
515 };
516
517
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