summaryrefslogtreecommitdiff
path: root/drivers/usb/storage/scsiglue.c
blob: b4c9e0f18a823b88033bb19c0e8dfc96115fc316 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
/* Driver for USB Mass Storage compliant devices
 * SCSI layer glue code
 *
 * Current development and maintenance by:
 *   (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
 *
 * Developed with the assistance of:
 *   (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
 *   (c) 2000 Stephen J. Gowdy (SGowdy@lbl.gov)
 *
 * Initial work by:
 *   (c) 1999 Michael Gee (michael@linuxspecific.com)
 *
 * This driver is based on the 'USB Mass Storage Class' document. This
 * describes in detail the protocol used to communicate with such
 * devices.  Clearly, the designers had SCSI and ATAPI commands in
 * mind when they created this document.  The commands are all very
 * similar to commands in the SCSI-II and ATAPI specifications.
 *
 * It is important to note that in a number of cases this class
 * exhibits class-specific exemptions from the USB specification.
 * Notably the usage of NAK, STALL and ACK differs from the norm, in
 * that they are used to communicate wait, failed and OK on commands.
 *
 * Also, for certain devices, the interrupt endpoint is used to convey
 * status of a command.
 *
 * Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
 * information about this driver.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/mutex.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_devinfo.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>

#include "usb.h"
#include "scsiglue.h"
#include "debug.h"
#include "transport.h"
#include "protocol.h"

/***********************************************************************
 * Host functions 
 ***********************************************************************/

static const char* host_info(struct Scsi_Host *host)
{
	return "SCSI emulation for USB Mass Storage devices";
}

static int slave_alloc (struct scsi_device *sdev)
{
	struct us_data *us = host_to_us(sdev->host);
	struct usb_host_endpoint *bulk_in_ep;

	/*
	 * Set the INQUIRY transfer length to 36.  We don't use any of
	 * the extra data and many devices choke if asked for more or
	 * less than 36 bytes.
	 */
	sdev->inquiry_len = 36;

	/* Scatter-gather buffers (all but the last) must have a length
	 * divisible by the bulk maxpacket size.  Otherwise a data packet
	 * would end up being short, causing a premature end to the data
	 * transfer.  We'll use the maxpacket value of the bulk-IN pipe
	 * to set the SCSI device queue's DMA alignment mask.
	 */
	bulk_in_ep = us->pusb_dev->ep_in[usb_pipeendpoint(us->recv_bulk_pipe)];
	blk_queue_update_dma_alignment(sdev->request_queue,
			le16_to_cpu(bulk_in_ep->desc.wMaxPacketSize) - 1);
			/* wMaxPacketSize must be a power of 2 */

	/*
	 * The UFI spec treates the Peripheral Qualifier bits in an
	 * INQUIRY result as reserved and requires devices to set them
	 * to 0.  However the SCSI spec requires these bits to be set
	 * to 3 to indicate when a LUN is not present.
	 *
	 * Let the scanning code know if this target merely sets
	 * Peripheral Device Type to 0x1f to indicate no LUN.
	 */
	if (us->subclass == US_SC_UFI)
		sdev->sdev_target->pdt_1f_for_no_lun = 1;

	return 0;
}

static int slave_configure(struct scsi_device *sdev)
{
	struct us_data *us = host_to_us(sdev->host);

	/* Many devices have trouble transfering more than 32KB at a time,
	 * while others have trouble with more than 64K. At this time we
	 * are limiting both to 32K (64 sectores).
	 */
	if (us->fflags & (US_FL_MAX_SECTORS_64 | US_FL_MAX_SECTORS_MIN)) {
		unsigned int max_sectors = 64;

		if (us->fflags & US_FL_MAX_SECTORS_MIN)
			max_sectors = PAGE_CACHE_SIZE >> 9;
		if (sdev->request_queue->max_sectors > max_sectors)
			blk_queue_max_sectors(sdev->request_queue,
					      max_sectors);
	}

	/* We can't put these settings in slave_alloc() because that gets
	 * called before the device type is known.  Consequently these
	 * settings can't be overridden via the scsi devinfo mechanism. */
	if (sdev->type == TYPE_DISK) {

		/* Disk-type devices use MODE SENSE(6) if the protocol
		 * (SubClass) is Transparent SCSI, otherwise they use
		 * MODE SENSE(10). */
		if (us->subclass != US_SC_SCSI && us->subclass != US_SC_CYP_ATACB)
			sdev->use_10_for_ms = 1;

		/* Many disks only accept MODE SENSE transfer lengths of
		 * 192 bytes (that's what Windows uses). */
		sdev->use_192_bytes_for_3f = 1;

		/* Some devices don't like MODE SENSE with page=0x3f,
		 * which is the command used for checking if a device
		 * is write-protected.  Now that we tell the sd driver
		 * to do a 192-byte transfer with this command the
		 * majority of devices work fine, but a few still can't
		 * handle it.  The sd driver will simply assume those
		 * devices are write-enabled. */
		if (us->fflags & US_FL_NO_WP_DETECT)
			sdev->skip_ms_page_3f = 1;

		/* A number of devices have problems with MODE SENSE for
		 * page x08, so we will skip it. */
		sdev->skip_ms_page_8 = 1;

		/* Some disks return the total number of blocks in response
		 * to READ CAPACITY rather than the highest block number.
		 * If this device makes that mistake, tell the sd driver. */
		if (us->fflags & US_FL_FIX_CAPACITY)
			sdev->fix_capacity = 1;

		/* A few disks have two indistinguishable version, one of
		 * which reports the correct capacity and the other does not.
		 * The sd driver has to guess which is the case. */
		if (us->fflags & US_FL_CAPACITY_HEURISTICS)
			sdev->guess_capacity = 1;

		/* Some devices report a SCSI revision level above 2 but are
		 * unable to handle the REPORT LUNS command (for which
		 * support is mandatory at level 3).  Since we already have
		 * a Get-Max-LUN request, we won't lose much by setting the
		 * revision level down to 2.  The only devices that would be
		 * affected are those with sparse LUNs. */
		if (sdev->scsi_level > SCSI_2)
			sdev->sdev_target->scsi_level =
					sdev->scsi_level = SCSI_2;

		/* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
		 * Hardware Error) when any low-level error occurs,
		 * recoverable or not.  Setting this flag tells the SCSI
		 * midlayer to retry such commands, which frequently will
		 * succeed and fix the error.  The worst this can lead to
		 * is an occasional series of retries that will all fail. */
		sdev->retry_hwerror = 1;

		/* USB disks should allow restart.  Some drives spin down
		 * automatically, requiring a START-STOP UNIT command. */
		sdev->allow_restart = 1;

		/* Some USB cardreaders have trouble reading an sdcard's last
		 * sector in a larger then 1 sector read, since the performance
		 * impact is negible we set this flag for all USB disks */
		sdev->last_sector_bug = 1;
	} else {

		/* Non-disk-type devices don't need to blacklist any pages
		 * or to force 192-byte transfer lengths for MODE SENSE.
		 * But they do need to use MODE SENSE(10). */
		sdev->use_10_for_ms = 1;
	}

	/* The CB and CBI transports have no way to pass LUN values
	 * other than the bits in the second byte of a CDB.  But those
	 * bits don't get set to the LUN value if the device reports
	 * scsi_level == 0 (UNKNOWN).  Hence such devices must necessarily
	 * be single-LUN.
	 */
	if ((us->protocol == US_PR_CB || us->protocol == US_PR_CBI) &&
			sdev->scsi_level == SCSI_UNKNOWN)
		us->max_lun = 0;

	/* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
	 * REMOVAL command, so suppress those commands. */
	if (us->fflags & US_FL_NOT_LOCKABLE)
		sdev->lockable = 0;

	/* this is to satisfy the compiler, tho I don't think the 
	 * return code is ever checked anywhere. */
	return 0;
}

/* queue a command */
/* This is always called with scsi_lock(host) held */
static int queuecommand(struct scsi_cmnd *srb,
			void (*done)(struct scsi_cmnd *))
{
	struct us_data *us = host_to_us(srb->device->host);

	US_DEBUGP("%s called\n", __func__);

	/* check for state-transition errors */
	if (us->srb != NULL) {
		printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n",
			__func__, us->srb);
		return SCSI_MLQUEUE_HOST_BUSY;
	}

	/* fail the command if we are disconnecting */
	if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
		US_DEBUGP("Fail command during disconnect\n");
		srb->result = DID_NO_CONNECT << 16;
		done(srb);
		return 0;
	}

	/* enqueue the command and wake up the control thread */
	srb->scsi_done = done;
	us->srb = srb;
	complete(&us->cmnd_ready);

	return 0;
}

/***********************************************************************
 * Error handling functions
 ***********************************************************************/

/* Command timeout and abort */
static int command_abort(struct scsi_cmnd *srb)
{
	struct us_data *us = host_to_us(srb->device->host);

	US_DEBUGP("%s called\n", __func__);

	/* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
	 * bits are protected by the host lock. */
	scsi_lock(us_to_host(us));

	/* Is this command still active? */
	if (us->srb != srb) {
		scsi_unlock(us_to_host(us));
		US_DEBUGP ("-- nothing to abort\n");
		return FAILED;
	}

	/* Set the TIMED_OUT bit.  Also set the ABORTING bit, but only if
	 * a device reset isn't already in progress (to avoid interfering
	 * with the reset).  Note that we must retain the host lock while
	 * calling usb_stor_stop_transport(); otherwise it might interfere
	 * with an auto-reset that begins as soon as we release the lock. */
	set_bit(US_FLIDX_TIMED_OUT, &us->dflags);
	if (!test_bit(US_FLIDX_RESETTING, &us->dflags)) {
		set_bit(US_FLIDX_ABORTING, &us->dflags);
		usb_stor_stop_transport(us);
	}
	scsi_unlock(us_to_host(us));

	/* Wait for the aborted command to finish */
	wait_for_completion(&us->notify);
	return SUCCESS;
}

/* This invokes the transport reset mechanism to reset the state of the
 * device */
static int device_reset(struct scsi_cmnd *srb)
{
	struct us_data *us = host_to_us(srb->device->host);
	int result;

	US_DEBUGP("%s called\n", __func__);

	/* lock the device pointers and do the reset */
	mutex_lock(&(us->dev_mutex));
	result = us->transport_reset(us);
	mutex_unlock(&us->dev_mutex);

	return result < 0 ? FAILED : SUCCESS;
}

/* Simulate a SCSI bus reset by resetting the device's USB port. */
static int bus_reset(struct scsi_cmnd *srb)
{
	struct us_data *us = host_to_us(srb->device->host);
	int result;

	US_DEBUGP("%s called\n", __func__);
	result = usb_stor_port_reset(us);
	return result < 0 ? FAILED : SUCCESS;
}

/* Report a driver-initiated device reset to the SCSI layer.
 * Calling this for a SCSI-initiated reset is unnecessary but harmless.
 * The caller must own the SCSI host lock. */
void usb_stor_report_device_reset(struct us_data *us)
{
	int i;
	struct Scsi_Host *host = us_to_host(us);

	scsi_report_device_reset(host, 0, 0);
	if (us->fflags & US_FL_SCM_MULT_TARG) {
		for (i = 1; i < host->max_id; ++i)
			scsi_report_device_reset(host, 0, i);
	}
}

/* Report a driver-initiated bus reset to the SCSI layer.
 * Calling this for a SCSI-initiated reset is unnecessary but harmless.
 * The caller must not own the SCSI host lock. */
void usb_stor_report_bus_reset(struct us_data *us)
{
	struct Scsi_Host *host = us_to_host(us);

	scsi_lock(host);
	scsi_report_bus_reset(host, 0);
	scsi_unlock(host);
}

/***********************************************************************
 * /proc/scsi/ functions
 ***********************************************************************/

/* we use this macro to help us write into the buffer */
#undef SPRINTF
#define SPRINTF(args...) \
	do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)

static int proc_info (struct Scsi_Host *host, char *buffer,
		char **start, off_t offset, int length, int inout)
{
	struct us_data *us = host_to_us(host);
	char *pos = buffer;
	const char *string;

	/* if someone is sending us data, just throw it away */
	if (inout)
		return length;

	/* print the controller name */
	SPRINTF("   Host scsi%d: usb-storage\n", host->host_no);

	/* print product, vendor, and serial number strings */
	if (us->pusb_dev->manufacturer)
		string = us->pusb_dev->manufacturer;
	else if (us->unusual_dev->vendorName)
		string = us->unusual_dev->vendorName;
	else
		string = "Unknown";
	SPRINTF("       Vendor: %s\n", string);
	if (us->pusb_dev->product)
		string = us->pusb_dev->product;
	else if (us->unusual_dev->productName)
		string = us->unusual_dev->productName;
	else
		string = "Unknown";
	SPRINTF("      Product: %s\n", string);
	if (us->pusb_dev->serial)
		string = us->pusb_dev->serial;
	else
		string = "None";
	SPRINTF("Serial Number: %s\n", string);

	/* show the protocol and transport */
	SPRINTF("     Protocol: %s\n", us->protocol_name);
	SPRINTF("    Transport: %s\n", us->transport_name);

	/* show the device flags */
	if (pos < buffer + length) {
		pos += sprintf(pos, "       Quirks:");

#define US_FLAG(name, value) \
	if (us->fflags & value) pos += sprintf(pos, " " #name);
US_DO_ALL_FLAGS
#undef US_FLAG

		*(pos++) = '\n';
	}

	/*
	 * Calculate start of next buffer, and return value.
	 */
	*start = buffer + offset;

	if ((pos - buffer) < offset)
		return (0);
	else if ((pos - buffer - offset) < length)
		return (pos - buffer - offset);
	else
		return (length);
}

/***********************************************************************
 * Sysfs interface
 ***********************************************************************/

/* Output routine for the sysfs max_sectors file */
static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct scsi_device *sdev = to_scsi_device(dev);

	return sprintf(buf, "%u\n", sdev->request_queue->max_sectors);
}

/* Input routine for the sysfs max_sectors file */
static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf,
		size_t count)
{
	struct scsi_device *sdev = to_scsi_device(dev);
	unsigned short ms;

	if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) {
		blk_queue_max_sectors(sdev->request_queue, ms);
		return strlen(buf);
	}
	return -EINVAL;	
}

static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors,
		store_max_sectors);

static struct device_attribute *sysfs_device_attr_list[] = {
		&dev_attr_max_sectors,
		NULL,
		};

/*
 * this defines our host template, with which we'll allocate hosts
 */

struct scsi_host_template usb_stor_host_template = {
	/* basic userland interface stuff */
	.name =				"usb-storage",
	.proc_name =			"usb-storage",
	.proc_info =			proc_info,
	.info =				host_info,

	/* command interface -- queued only */
	.queuecommand =			queuecommand,

	/* error and abort handlers */
	.eh_abort_handler =		command_abort,
	.eh_device_reset_handler =	device_reset,
	.eh_bus_reset_handler =		bus_reset,

	/* queue commands only, only one command per LUN */
	.can_queue =			1,
	.cmd_per_lun =			1,

	/* unknown initiator id */
	.this_id =			-1,

	.slave_alloc =			slave_alloc,
	.slave_configure =		slave_configure,

	/* lots of sg segments can be handled */
	.sg_tablesize =			SG_ALL,

	/* limit the total size of a transfer to 120 KB */
	.max_sectors =                  240,

	/* merge commands... this seems to help performance, but
	 * periodically someone should test to see which setting is more
	 * optimal.
	 */
	.use_clustering =		1,

	/* emulated HBA */
	.emulated =			1,

	/* we do our own delay after a device or bus reset */
	.skip_settle_delay =		1,

	/* sysfs device attributes */
	.sdev_attrs =			sysfs_device_attr_list,

	/* module management */
	.module =			THIS_MODULE
};

/* To Report "Illegal Request: Invalid Field in CDB */
unsigned char usb_stor_sense_invalidCDB[18] = {
	[0]	= 0x70,			    /* current error */
	[2]	= ILLEGAL_REQUEST,	    /* Illegal Request = 0x05 */
	[7]	= 0x0a,			    /* additional length */
	[12]	= 0x24			    /* Invalid Field in CDB */
};