1 /* Driver for USB Mass Storage compliant devices
4 * Current development and maintenance by:
5 * (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
7 * Developed with the assistance of:
8 * (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
9 * (c) 2000 Stephen J. Gowdy (SGowdy@lbl.gov)
12 * (c) 1999 Michael Gee (michael@linuxspecific.com)
14 * This driver is based on the 'USB Mass Storage Class' document. This
15 * describes in detail the protocol used to communicate with such
16 * devices. Clearly, the designers had SCSI and ATAPI commands in
17 * mind when they created this document. The commands are all very
18 * similar to commands in the SCSI-II and ATAPI specifications.
20 * It is important to note that in a number of cases this class
21 * exhibits class-specific exemptions from the USB specification.
22 * Notably the usage of NAK, STALL and ACK differs from the norm, in
23 * that they are used to communicate wait, failed and OK on commands.
25 * Also, for certain devices, the interrupt endpoint is used to convey
26 * status of a command.
28 * Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
29 * information about this driver.
31 * This program is free software; you can redistribute it and/or modify it
32 * under the terms of the GNU General Public License as published by the
33 * Free Software Foundation; either version 2, or (at your option) any
36 * This program is distributed in the hope that it will be useful, but
37 * WITHOUT ANY WARRANTY; without even the implied warranty of
38 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
39 * General Public License for more details.
41 * You should have received a copy of the GNU General Public License along
42 * with this program; if not, write to the Free Software Foundation, Inc.,
43 * 675 Mass Ave, Cambridge, MA 02139, USA.
46 #include <linux/slab.h>
47 #include <linux/module.h>
48 #include <linux/mutex.h>
50 #include <scsi/scsi.h>
51 #include <scsi/scsi_cmnd.h>
52 #include <scsi/scsi_devinfo.h>
53 #include <scsi/scsi_device.h>
54 #include <scsi/scsi_eh.h>
59 #include "transport.h"
62 /***********************************************************************
64 ***********************************************************************/
66 static const char* host_info(struct Scsi_Host
*host
)
68 return "SCSI emulation for USB Mass Storage devices";
71 static int slave_alloc (struct scsi_device
*sdev
)
73 struct us_data
*us
= host_to_us(sdev
->host
);
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
80 sdev
->inquiry_len
= 36;
82 /* USB has unusual DMA-alignment requirements: Although the
83 * starting address of each scatter-gather element doesn't matter,
84 * the length of each element except the last must be divisible
85 * by the Bulk maxpacket value. There's currently no way to
86 * express this by block-layer constraints, so we'll cop out
87 * and simply require addresses to be aligned at 512-byte
88 * boundaries. This is okay since most block I/O involves
89 * hardware sectors that are multiples of 512 bytes in length,
90 * and since host controllers up through USB 2.0 have maxpacket
91 * values no larger than 512.
93 * But it doesn't suffice for Wireless USB, where Bulk maxpacket
94 * values can be as large as 2048. To make that work properly
95 * will require changes to the block layer.
97 blk_queue_update_dma_alignment(sdev
->request_queue
, (512 - 1));
100 * The UFI spec treates the Peripheral Qualifier bits in an
101 * INQUIRY result as reserved and requires devices to set them
102 * to 0. However the SCSI spec requires these bits to be set
103 * to 3 to indicate when a LUN is not present.
105 * Let the scanning code know if this target merely sets
106 * Peripheral Device Type to 0x1f to indicate no LUN.
108 if (us
->subclass
== US_SC_UFI
)
109 sdev
->sdev_target
->pdt_1f_for_no_lun
= 1;
114 static int slave_configure(struct scsi_device
*sdev
)
116 struct us_data
*us
= host_to_us(sdev
->host
);
118 /* Many devices have trouble transfering more than 32KB at a time,
119 * while others have trouble with more than 64K. At this time we
120 * are limiting both to 32K (64 sectores).
122 if (us
->fflags
& (US_FL_MAX_SECTORS_64
| US_FL_MAX_SECTORS_MIN
)) {
123 unsigned int max_sectors
= 64;
125 if (us
->fflags
& US_FL_MAX_SECTORS_MIN
)
126 max_sectors
= PAGE_CACHE_SIZE
>> 9;
127 if (sdev
->request_queue
->max_sectors
> max_sectors
)
128 blk_queue_max_sectors(sdev
->request_queue
,
132 /* Some USB host controllers can't do DMA; they have to use PIO.
133 * They indicate this by setting their dma_mask to NULL. For
134 * such controllers we need to make sure the block layer sets
135 * up bounce buffers in addressable memory.
137 if (!us
->pusb_dev
->bus
->controller
->dma_mask
)
138 blk_queue_bounce_limit(sdev
->request_queue
, BLK_BOUNCE_HIGH
);
140 /* We can't put these settings in slave_alloc() because that gets
141 * called before the device type is known. Consequently these
142 * settings can't be overridden via the scsi devinfo mechanism. */
143 if (sdev
->type
== TYPE_DISK
) {
145 /* Disk-type devices use MODE SENSE(6) if the protocol
146 * (SubClass) is Transparent SCSI, otherwise they use
148 if (us
->subclass
!= US_SC_SCSI
&& us
->subclass
!= US_SC_CYP_ATACB
)
149 sdev
->use_10_for_ms
= 1;
151 /* Many disks only accept MODE SENSE transfer lengths of
152 * 192 bytes (that's what Windows uses). */
153 sdev
->use_192_bytes_for_3f
= 1;
155 /* Some devices don't like MODE SENSE with page=0x3f,
156 * which is the command used for checking if a device
157 * is write-protected. Now that we tell the sd driver
158 * to do a 192-byte transfer with this command the
159 * majority of devices work fine, but a few still can't
160 * handle it. The sd driver will simply assume those
161 * devices are write-enabled. */
162 if (us
->fflags
& US_FL_NO_WP_DETECT
)
163 sdev
->skip_ms_page_3f
= 1;
165 /* A number of devices have problems with MODE SENSE for
166 * page x08, so we will skip it. */
167 sdev
->skip_ms_page_8
= 1;
169 /* Some disks return the total number of blocks in response
170 * to READ CAPACITY rather than the highest block number.
171 * If this device makes that mistake, tell the sd driver. */
172 if (us
->fflags
& US_FL_FIX_CAPACITY
)
173 sdev
->fix_capacity
= 1;
175 /* A few disks have two indistinguishable version, one of
176 * which reports the correct capacity and the other does not.
177 * The sd driver has to guess which is the case. */
178 if (us
->fflags
& US_FL_CAPACITY_HEURISTICS
)
179 sdev
->guess_capacity
= 1;
181 /* assume SPC3 or latter devices support sense size > 18 */
182 if (sdev
->scsi_level
> SCSI_SPC_2
)
183 us
->fflags
|= US_FL_SANE_SENSE
;
185 /* Some devices report a SCSI revision level above 2 but are
186 * unable to handle the REPORT LUNS command (for which
187 * support is mandatory at level 3). Since we already have
188 * a Get-Max-LUN request, we won't lose much by setting the
189 * revision level down to 2. The only devices that would be
190 * affected are those with sparse LUNs. */
191 if (sdev
->scsi_level
> SCSI_2
)
192 sdev
->sdev_target
->scsi_level
=
193 sdev
->scsi_level
= SCSI_2
;
195 /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
196 * Hardware Error) when any low-level error occurs,
197 * recoverable or not. Setting this flag tells the SCSI
198 * midlayer to retry such commands, which frequently will
199 * succeed and fix the error. The worst this can lead to
200 * is an occasional series of retries that will all fail. */
201 sdev
->retry_hwerror
= 1;
203 /* USB disks should allow restart. Some drives spin down
204 * automatically, requiring a START-STOP UNIT command. */
205 sdev
->allow_restart
= 1;
207 /* Some USB cardreaders have trouble reading an sdcard's last
208 * sector in a larger then 1 sector read, since the performance
209 * impact is negible we set this flag for all USB disks */
210 sdev
->last_sector_bug
= 1;
212 /* Enable last-sector hacks for single-target devices using
213 * the Bulk-only transport, unless we already know the
214 * capacity will be decremented or is correct. */
215 if (!(us
->fflags
& (US_FL_FIX_CAPACITY
| US_FL_CAPACITY_OK
|
216 US_FL_SCM_MULT_TARG
)) &&
217 us
->protocol
== US_PR_BULK
)
218 us
->use_last_sector_hacks
= 1;
221 /* Non-disk-type devices don't need to blacklist any pages
222 * or to force 192-byte transfer lengths for MODE SENSE.
223 * But they do need to use MODE SENSE(10). */
224 sdev
->use_10_for_ms
= 1;
227 /* The CB and CBI transports have no way to pass LUN values
228 * other than the bits in the second byte of a CDB. But those
229 * bits don't get set to the LUN value if the device reports
230 * scsi_level == 0 (UNKNOWN). Hence such devices must necessarily
233 if ((us
->protocol
== US_PR_CB
|| us
->protocol
== US_PR_CBI
) &&
234 sdev
->scsi_level
== SCSI_UNKNOWN
)
237 /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
238 * REMOVAL command, so suppress those commands. */
239 if (us
->fflags
& US_FL_NOT_LOCKABLE
)
242 /* this is to satisfy the compiler, tho I don't think the
243 * return code is ever checked anywhere. */
247 /* queue a command */
248 /* This is always called with scsi_lock(host) held */
249 static int queuecommand(struct scsi_cmnd
*srb
,
250 void (*done
)(struct scsi_cmnd
*))
252 struct us_data
*us
= host_to_us(srb
->device
->host
);
254 US_DEBUGP("%s called\n", __func__
);
256 /* check for state-transition errors */
257 if (us
->srb
!= NULL
) {
258 printk(KERN_ERR USB_STORAGE
"Error in %s: us->srb = %p\n",
260 return SCSI_MLQUEUE_HOST_BUSY
;
263 /* fail the command if we are disconnecting */
264 if (test_bit(US_FLIDX_DISCONNECTING
, &us
->dflags
)) {
265 US_DEBUGP("Fail command during disconnect\n");
266 srb
->result
= DID_NO_CONNECT
<< 16;
271 /* enqueue the command and wake up the control thread */
272 srb
->scsi_done
= done
;
274 complete(&us
->cmnd_ready
);
279 /***********************************************************************
280 * Error handling functions
281 ***********************************************************************/
283 /* Command timeout and abort */
284 static int command_abort(struct scsi_cmnd
*srb
)
286 struct us_data
*us
= host_to_us(srb
->device
->host
);
288 US_DEBUGP("%s called\n", __func__
);
290 /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
291 * bits are protected by the host lock. */
292 scsi_lock(us_to_host(us
));
294 /* Is this command still active? */
295 if (us
->srb
!= srb
) {
296 scsi_unlock(us_to_host(us
));
297 US_DEBUGP ("-- nothing to abort\n");
301 /* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if
302 * a device reset isn't already in progress (to avoid interfering
303 * with the reset). Note that we must retain the host lock while
304 * calling usb_stor_stop_transport(); otherwise it might interfere
305 * with an auto-reset that begins as soon as we release the lock. */
306 set_bit(US_FLIDX_TIMED_OUT
, &us
->dflags
);
307 if (!test_bit(US_FLIDX_RESETTING
, &us
->dflags
)) {
308 set_bit(US_FLIDX_ABORTING
, &us
->dflags
);
309 usb_stor_stop_transport(us
);
311 scsi_unlock(us_to_host(us
));
313 /* Wait for the aborted command to finish */
314 wait_for_completion(&us
->notify
);
318 /* This invokes the transport reset mechanism to reset the state of the
320 static int device_reset(struct scsi_cmnd
*srb
)
322 struct us_data
*us
= host_to_us(srb
->device
->host
);
325 US_DEBUGP("%s called\n", __func__
);
327 /* lock the device pointers and do the reset */
328 mutex_lock(&(us
->dev_mutex
));
329 result
= us
->transport_reset(us
);
330 mutex_unlock(&us
->dev_mutex
);
332 return result
< 0 ? FAILED
: SUCCESS
;
335 /* Simulate a SCSI bus reset by resetting the device's USB port. */
336 static int bus_reset(struct scsi_cmnd
*srb
)
338 struct us_data
*us
= host_to_us(srb
->device
->host
);
341 US_DEBUGP("%s called\n", __func__
);
342 result
= usb_stor_port_reset(us
);
343 return result
< 0 ? FAILED
: SUCCESS
;
346 /* Report a driver-initiated device reset to the SCSI layer.
347 * Calling this for a SCSI-initiated reset is unnecessary but harmless.
348 * The caller must own the SCSI host lock. */
349 void usb_stor_report_device_reset(struct us_data
*us
)
352 struct Scsi_Host
*host
= us_to_host(us
);
354 scsi_report_device_reset(host
, 0, 0);
355 if (us
->fflags
& US_FL_SCM_MULT_TARG
) {
356 for (i
= 1; i
< host
->max_id
; ++i
)
357 scsi_report_device_reset(host
, 0, i
);
361 /* Report a driver-initiated bus reset to the SCSI layer.
362 * Calling this for a SCSI-initiated reset is unnecessary but harmless.
363 * The caller must not own the SCSI host lock. */
364 void usb_stor_report_bus_reset(struct us_data
*us
)
366 struct Scsi_Host
*host
= us_to_host(us
);
369 scsi_report_bus_reset(host
, 0);
373 /***********************************************************************
374 * /proc/scsi/ functions
375 ***********************************************************************/
377 /* we use this macro to help us write into the buffer */
379 #define SPRINTF(args...) \
380 do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)
382 static int proc_info (struct Scsi_Host
*host
, char *buffer
,
383 char **start
, off_t offset
, int length
, int inout
)
385 struct us_data
*us
= host_to_us(host
);
389 /* if someone is sending us data, just throw it away */
393 /* print the controller name */
394 SPRINTF(" Host scsi%d: usb-storage\n", host
->host_no
);
396 /* print product, vendor, and serial number strings */
397 if (us
->pusb_dev
->manufacturer
)
398 string
= us
->pusb_dev
->manufacturer
;
399 else if (us
->unusual_dev
->vendorName
)
400 string
= us
->unusual_dev
->vendorName
;
403 SPRINTF(" Vendor: %s\n", string
);
404 if (us
->pusb_dev
->product
)
405 string
= us
->pusb_dev
->product
;
406 else if (us
->unusual_dev
->productName
)
407 string
= us
->unusual_dev
->productName
;
410 SPRINTF(" Product: %s\n", string
);
411 if (us
->pusb_dev
->serial
)
412 string
= us
->pusb_dev
->serial
;
415 SPRINTF("Serial Number: %s\n", string
);
417 /* show the protocol and transport */
418 SPRINTF(" Protocol: %s\n", us
->protocol_name
);
419 SPRINTF(" Transport: %s\n", us
->transport_name
);
421 /* show the device flags */
422 if (pos
< buffer
+ length
) {
423 pos
+= sprintf(pos
, " Quirks:");
425 #define US_FLAG(name, value) \
426 if (us->fflags & value) pos += sprintf(pos, " " #name);
434 * Calculate start of next buffer, and return value.
436 *start
= buffer
+ offset
;
438 if ((pos
- buffer
) < offset
)
440 else if ((pos
- buffer
- offset
) < length
)
441 return (pos
- buffer
- offset
);
446 /***********************************************************************
448 ***********************************************************************/
450 /* Output routine for the sysfs max_sectors file */
451 static ssize_t
show_max_sectors(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
453 struct scsi_device
*sdev
= to_scsi_device(dev
);
455 return sprintf(buf
, "%u\n", sdev
->request_queue
->max_sectors
);
458 /* Input routine for the sysfs max_sectors file */
459 static ssize_t
store_max_sectors(struct device
*dev
, struct device_attribute
*attr
, const char *buf
,
462 struct scsi_device
*sdev
= to_scsi_device(dev
);
465 if (sscanf(buf
, "%hu", &ms
) > 0 && ms
<= SCSI_DEFAULT_MAX_SECTORS
) {
466 blk_queue_max_sectors(sdev
->request_queue
, ms
);
472 static DEVICE_ATTR(max_sectors
, S_IRUGO
| S_IWUSR
, show_max_sectors
,
475 static struct device_attribute
*sysfs_device_attr_list
[] = {
476 &dev_attr_max_sectors
,
481 * this defines our host template, with which we'll allocate hosts
484 struct scsi_host_template usb_stor_host_template
= {
485 /* basic userland interface stuff */
486 .name
= "usb-storage",
487 .proc_name
= "usb-storage",
488 .proc_info
= proc_info
,
491 /* command interface -- queued only */
492 .queuecommand
= queuecommand
,
494 /* error and abort handlers */
495 .eh_abort_handler
= command_abort
,
496 .eh_device_reset_handler
= device_reset
,
497 .eh_bus_reset_handler
= bus_reset
,
499 /* queue commands only, only one command per LUN */
503 /* unknown initiator id */
506 .slave_alloc
= slave_alloc
,
507 .slave_configure
= slave_configure
,
509 /* lots of sg segments can be handled */
510 .sg_tablesize
= SG_ALL
,
512 /* limit the total size of a transfer to 120 KB */
515 /* merge commands... this seems to help performance, but
516 * periodically someone should test to see which setting is more
524 /* we do our own delay after a device or bus reset */
525 .skip_settle_delay
= 1,
527 /* sysfs device attributes */
528 .sdev_attrs
= sysfs_device_attr_list
,
530 /* module management */
531 .module
= THIS_MODULE
534 /* To Report "Illegal Request: Invalid Field in CDB */
535 unsigned char usb_stor_sense_invalidCDB
[18] = {
536 [0] = 0x70, /* current error */
537 [2] = ILLEGAL_REQUEST
, /* Illegal Request = 0x05 */
538 [7] = 0x0a, /* additional length */
539 [12] = 0x24 /* Invalid Field in CDB */