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 /* We can't put these settings in slave_alloc() because that gets
133 * called before the device type is known. Consequently these
134 * settings can't be overridden via the scsi devinfo mechanism. */
135 if (sdev
->type
== TYPE_DISK
) {
137 /* Disk-type devices use MODE SENSE(6) if the protocol
138 * (SubClass) is Transparent SCSI, otherwise they use
140 if (us
->subclass
!= US_SC_SCSI
&& us
->subclass
!= US_SC_CYP_ATACB
)
141 sdev
->use_10_for_ms
= 1;
143 /* Many disks only accept MODE SENSE transfer lengths of
144 * 192 bytes (that's what Windows uses). */
145 sdev
->use_192_bytes_for_3f
= 1;
147 /* Some devices don't like MODE SENSE with page=0x3f,
148 * which is the command used for checking if a device
149 * is write-protected. Now that we tell the sd driver
150 * to do a 192-byte transfer with this command the
151 * majority of devices work fine, but a few still can't
152 * handle it. The sd driver will simply assume those
153 * devices are write-enabled. */
154 if (us
->fflags
& US_FL_NO_WP_DETECT
)
155 sdev
->skip_ms_page_3f
= 1;
157 /* A number of devices have problems with MODE SENSE for
158 * page x08, so we will skip it. */
159 sdev
->skip_ms_page_8
= 1;
161 /* Some disks return the total number of blocks in response
162 * to READ CAPACITY rather than the highest block number.
163 * If this device makes that mistake, tell the sd driver. */
164 if (us
->fflags
& US_FL_FIX_CAPACITY
)
165 sdev
->fix_capacity
= 1;
167 /* A few disks have two indistinguishable version, one of
168 * which reports the correct capacity and the other does not.
169 * The sd driver has to guess which is the case. */
170 if (us
->fflags
& US_FL_CAPACITY_HEURISTICS
)
171 sdev
->guess_capacity
= 1;
173 /* Some devices report a SCSI revision level above 2 but are
174 * unable to handle the REPORT LUNS command (for which
175 * support is mandatory at level 3). Since we already have
176 * a Get-Max-LUN request, we won't lose much by setting the
177 * revision level down to 2. The only devices that would be
178 * affected are those with sparse LUNs. */
179 if (sdev
->scsi_level
> SCSI_2
)
180 sdev
->sdev_target
->scsi_level
=
181 sdev
->scsi_level
= SCSI_2
;
183 /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
184 * Hardware Error) when any low-level error occurs,
185 * recoverable or not. Setting this flag tells the SCSI
186 * midlayer to retry such commands, which frequently will
187 * succeed and fix the error. The worst this can lead to
188 * is an occasional series of retries that will all fail. */
189 sdev
->retry_hwerror
= 1;
191 /* USB disks should allow restart. Some drives spin down
192 * automatically, requiring a START-STOP UNIT command. */
193 sdev
->allow_restart
= 1;
195 /* Some USB cardreaders have trouble reading an sdcard's last
196 * sector in a larger then 1 sector read, since the performance
197 * impact is negible we set this flag for all USB disks */
198 sdev
->last_sector_bug
= 1;
200 /* Enable last-sector hacks for single-target devices using
201 * the Bulk-only transport, unless we already know the
202 * capacity will be decremented or is correct. */
203 if (!(us
->fflags
& (US_FL_FIX_CAPACITY
| US_FL_CAPACITY_OK
|
204 US_FL_SCM_MULT_TARG
)) &&
205 us
->protocol
== US_PR_BULK
)
206 us
->use_last_sector_hacks
= 1;
209 /* Non-disk-type devices don't need to blacklist any pages
210 * or to force 192-byte transfer lengths for MODE SENSE.
211 * But they do need to use MODE SENSE(10). */
212 sdev
->use_10_for_ms
= 1;
215 /* The CB and CBI transports have no way to pass LUN values
216 * other than the bits in the second byte of a CDB. But those
217 * bits don't get set to the LUN value if the device reports
218 * scsi_level == 0 (UNKNOWN). Hence such devices must necessarily
221 if ((us
->protocol
== US_PR_CB
|| us
->protocol
== US_PR_CBI
) &&
222 sdev
->scsi_level
== SCSI_UNKNOWN
)
225 /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
226 * REMOVAL command, so suppress those commands. */
227 if (us
->fflags
& US_FL_NOT_LOCKABLE
)
230 /* this is to satisfy the compiler, tho I don't think the
231 * return code is ever checked anywhere. */
235 /* queue a command */
236 /* This is always called with scsi_lock(host) held */
237 static int queuecommand(struct scsi_cmnd
*srb
,
238 void (*done
)(struct scsi_cmnd
*))
240 struct us_data
*us
= host_to_us(srb
->device
->host
);
242 US_DEBUGP("%s called\n", __func__
);
244 /* check for state-transition errors */
245 if (us
->srb
!= NULL
) {
246 printk(KERN_ERR USB_STORAGE
"Error in %s: us->srb = %p\n",
248 return SCSI_MLQUEUE_HOST_BUSY
;
251 /* fail the command if we are disconnecting */
252 if (test_bit(US_FLIDX_DISCONNECTING
, &us
->dflags
)) {
253 US_DEBUGP("Fail command during disconnect\n");
254 srb
->result
= DID_NO_CONNECT
<< 16;
259 /* enqueue the command and wake up the control thread */
260 srb
->scsi_done
= done
;
262 complete(&us
->cmnd_ready
);
267 /***********************************************************************
268 * Error handling functions
269 ***********************************************************************/
271 /* Command timeout and abort */
272 static int command_abort(struct scsi_cmnd
*srb
)
274 struct us_data
*us
= host_to_us(srb
->device
->host
);
276 US_DEBUGP("%s called\n", __func__
);
278 /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
279 * bits are protected by the host lock. */
280 scsi_lock(us_to_host(us
));
282 /* Is this command still active? */
283 if (us
->srb
!= srb
) {
284 scsi_unlock(us_to_host(us
));
285 US_DEBUGP ("-- nothing to abort\n");
289 /* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if
290 * a device reset isn't already in progress (to avoid interfering
291 * with the reset). Note that we must retain the host lock while
292 * calling usb_stor_stop_transport(); otherwise it might interfere
293 * with an auto-reset that begins as soon as we release the lock. */
294 set_bit(US_FLIDX_TIMED_OUT
, &us
->dflags
);
295 if (!test_bit(US_FLIDX_RESETTING
, &us
->dflags
)) {
296 set_bit(US_FLIDX_ABORTING
, &us
->dflags
);
297 usb_stor_stop_transport(us
);
299 scsi_unlock(us_to_host(us
));
301 /* Wait for the aborted command to finish */
302 wait_for_completion(&us
->notify
);
306 /* This invokes the transport reset mechanism to reset the state of the
308 static int device_reset(struct scsi_cmnd
*srb
)
310 struct us_data
*us
= host_to_us(srb
->device
->host
);
313 US_DEBUGP("%s called\n", __func__
);
315 /* lock the device pointers and do the reset */
316 mutex_lock(&(us
->dev_mutex
));
317 result
= us
->transport_reset(us
);
318 mutex_unlock(&us
->dev_mutex
);
320 return result
< 0 ? FAILED
: SUCCESS
;
323 /* Simulate a SCSI bus reset by resetting the device's USB port. */
324 static int bus_reset(struct scsi_cmnd
*srb
)
326 struct us_data
*us
= host_to_us(srb
->device
->host
);
329 US_DEBUGP("%s called\n", __func__
);
330 result
= usb_stor_port_reset(us
);
331 return result
< 0 ? FAILED
: SUCCESS
;
334 /* Report a driver-initiated device reset to the SCSI layer.
335 * Calling this for a SCSI-initiated reset is unnecessary but harmless.
336 * The caller must own the SCSI host lock. */
337 void usb_stor_report_device_reset(struct us_data
*us
)
340 struct Scsi_Host
*host
= us_to_host(us
);
342 scsi_report_device_reset(host
, 0, 0);
343 if (us
->fflags
& US_FL_SCM_MULT_TARG
) {
344 for (i
= 1; i
< host
->max_id
; ++i
)
345 scsi_report_device_reset(host
, 0, i
);
349 /* Report a driver-initiated bus reset to the SCSI layer.
350 * Calling this for a SCSI-initiated reset is unnecessary but harmless.
351 * The caller must not own the SCSI host lock. */
352 void usb_stor_report_bus_reset(struct us_data
*us
)
354 struct Scsi_Host
*host
= us_to_host(us
);
357 scsi_report_bus_reset(host
, 0);
361 /***********************************************************************
362 * /proc/scsi/ functions
363 ***********************************************************************/
365 /* we use this macro to help us write into the buffer */
367 #define SPRINTF(args...) \
368 do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)
370 static int proc_info (struct Scsi_Host
*host
, char *buffer
,
371 char **start
, off_t offset
, int length
, int inout
)
373 struct us_data
*us
= host_to_us(host
);
377 /* if someone is sending us data, just throw it away */
381 /* print the controller name */
382 SPRINTF(" Host scsi%d: usb-storage\n", host
->host_no
);
384 /* print product, vendor, and serial number strings */
385 if (us
->pusb_dev
->manufacturer
)
386 string
= us
->pusb_dev
->manufacturer
;
387 else if (us
->unusual_dev
->vendorName
)
388 string
= us
->unusual_dev
->vendorName
;
391 SPRINTF(" Vendor: %s\n", string
);
392 if (us
->pusb_dev
->product
)
393 string
= us
->pusb_dev
->product
;
394 else if (us
->unusual_dev
->productName
)
395 string
= us
->unusual_dev
->productName
;
398 SPRINTF(" Product: %s\n", string
);
399 if (us
->pusb_dev
->serial
)
400 string
= us
->pusb_dev
->serial
;
403 SPRINTF("Serial Number: %s\n", string
);
405 /* show the protocol and transport */
406 SPRINTF(" Protocol: %s\n", us
->protocol_name
);
407 SPRINTF(" Transport: %s\n", us
->transport_name
);
409 /* show the device flags */
410 if (pos
< buffer
+ length
) {
411 pos
+= sprintf(pos
, " Quirks:");
413 #define US_FLAG(name, value) \
414 if (us->fflags & value) pos += sprintf(pos, " " #name);
422 * Calculate start of next buffer, and return value.
424 *start
= buffer
+ offset
;
426 if ((pos
- buffer
) < offset
)
428 else if ((pos
- buffer
- offset
) < length
)
429 return (pos
- buffer
- offset
);
434 /***********************************************************************
436 ***********************************************************************/
438 /* Output routine for the sysfs max_sectors file */
439 static ssize_t
show_max_sectors(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
441 struct scsi_device
*sdev
= to_scsi_device(dev
);
443 return sprintf(buf
, "%u\n", sdev
->request_queue
->max_sectors
);
446 /* Input routine for the sysfs max_sectors file */
447 static ssize_t
store_max_sectors(struct device
*dev
, struct device_attribute
*attr
, const char *buf
,
450 struct scsi_device
*sdev
= to_scsi_device(dev
);
453 if (sscanf(buf
, "%hu", &ms
) > 0 && ms
<= SCSI_DEFAULT_MAX_SECTORS
) {
454 blk_queue_max_sectors(sdev
->request_queue
, ms
);
460 static DEVICE_ATTR(max_sectors
, S_IRUGO
| S_IWUSR
, show_max_sectors
,
463 static struct device_attribute
*sysfs_device_attr_list
[] = {
464 &dev_attr_max_sectors
,
469 * this defines our host template, with which we'll allocate hosts
472 struct scsi_host_template usb_stor_host_template
= {
473 /* basic userland interface stuff */
474 .name
= "usb-storage",
475 .proc_name
= "usb-storage",
476 .proc_info
= proc_info
,
479 /* command interface -- queued only */
480 .queuecommand
= queuecommand
,
482 /* error and abort handlers */
483 .eh_abort_handler
= command_abort
,
484 .eh_device_reset_handler
= device_reset
,
485 .eh_bus_reset_handler
= bus_reset
,
487 /* queue commands only, only one command per LUN */
491 /* unknown initiator id */
494 .slave_alloc
= slave_alloc
,
495 .slave_configure
= slave_configure
,
497 /* lots of sg segments can be handled */
498 .sg_tablesize
= SG_ALL
,
500 /* limit the total size of a transfer to 120 KB */
503 /* merge commands... this seems to help performance, but
504 * periodically someone should test to see which setting is more
512 /* we do our own delay after a device or bus reset */
513 .skip_settle_delay
= 1,
515 /* sysfs device attributes */
516 .sdev_attrs
= sysfs_device_attr_list
,
518 /* module management */
519 .module
= THIS_MODULE
522 /* To Report "Illegal Request: Invalid Field in CDB */
523 unsigned char usb_stor_sense_invalidCDB
[18] = {
524 [0] = 0x70, /* current error */
525 [2] = ILLEGAL_REQUEST
, /* Illegal Request = 0x05 */
526 [7] = 0x0a, /* additional length */
527 [12] = 0x24 /* Invalid Field in CDB */