1 /* Driver for USB Mass Storage compliant devices
4 * $Id: scsiglue.c,v 1.26 2002/04/22 03:39:43 mdharm Exp $
6 * Current development and maintenance by:
7 * (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
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)
14 * (c) 1999 Michael Gee (michael@linuxspecific.com)
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.
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.
27 * Also, for certain devices, the interrupt endpoint is used to convey
28 * status of a command.
30 * Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
31 * information about this driver.
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
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.
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.
48 #include <linux/slab.h>
49 #include <linux/module.h>
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>
60 #include "transport.h"
63 /***********************************************************************
65 ***********************************************************************/
67 static const char* host_info(struct Scsi_Host
*host
)
69 return "SCSI emulation for USB Mass Storage devices";
72 static int slave_alloc (struct scsi_device
*sdev
)
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
79 sdev
->inquiry_len
= 36;
83 static int slave_configure(struct scsi_device
*sdev
)
85 struct us_data
*us
= host_to_us(sdev
->host
);
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));
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).
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.
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
111 if (sdev
->scsi_level
< SCSI_2
)
112 sdev
->scsi_level
= SCSI_2
;
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);
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
) {
129 /* Disk-type devices use MODE SENSE(6) if the protocol
130 * (SubClass) is Transparent SCSI, otherwise they use
132 if (us
->subclass
!= US_SC_SCSI
)
133 sdev
->use_10_for_ms
= 1;
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;
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;
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;
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;
160 /* Non-disk-type devices don't need to blacklist any pages
161 * or to force 192-byte transfer lengths for MODE SENSE.
162 * But they do need to use MODE SENSE(10). */
163 sdev
->use_10_for_ms
= 1;
166 /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
167 * REMOVAL command, so suppress those commands. */
168 if (us
->flags
& US_FL_NOT_LOCKABLE
)
171 /* this is to satisfy the compiler, tho I don't think the
172 * return code is ever checked anywhere. */
176 /* queue a command */
177 /* This is always called with scsi_lock(host) held */
178 static int queuecommand(struct scsi_cmnd
*srb
,
179 void (*done
)(struct scsi_cmnd
*))
181 struct us_data
*us
= host_to_us(srb
->device
->host
);
183 US_DEBUGP("%s called\n", __FUNCTION__
);
185 /* check for state-transition errors */
186 if (us
->srb
!= NULL
) {
187 printk(KERN_ERR USB_STORAGE
"Error in %s: us->srb = %p\n",
188 __FUNCTION__
, us
->srb
);
189 return SCSI_MLQUEUE_HOST_BUSY
;
192 /* fail the command if we are disconnecting */
193 if (test_bit(US_FLIDX_DISCONNECTING
, &us
->flags
)) {
194 US_DEBUGP("Fail command during disconnect\n");
195 srb
->result
= DID_NO_CONNECT
<< 16;
200 /* enqueue the command and wake up the control thread */
201 srb
->scsi_done
= done
;
208 /***********************************************************************
209 * Error handling functions
210 ***********************************************************************/
212 /* Command timeout and abort */
213 /* This is always called with scsi_lock(host) held */
214 static int command_abort(struct scsi_cmnd
*srb
)
216 struct us_data
*us
= host_to_us(srb
->device
->host
);
218 US_DEBUGP("%s called\n", __FUNCTION__
);
220 /* Is this command still active? */
221 if (us
->srb
!= srb
) {
222 US_DEBUGP ("-- nothing to abort\n");
226 /* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if
227 * a device reset isn't already in progress (to avoid interfering
228 * with the reset). To prevent races with auto-reset, we must
229 * stop any ongoing USB transfers while still holding the host
231 set_bit(US_FLIDX_TIMED_OUT
, &us
->flags
);
232 if (!test_bit(US_FLIDX_RESETTING
, &us
->flags
)) {
233 set_bit(US_FLIDX_ABORTING
, &us
->flags
);
234 usb_stor_stop_transport(us
);
236 scsi_unlock(us_to_host(us
));
238 /* Wait for the aborted command to finish */
239 wait_for_completion(&us
->notify
);
241 /* Reacquire the lock and allow USB transfers to resume */
242 scsi_lock(us_to_host(us
));
243 clear_bit(US_FLIDX_ABORTING
, &us
->flags
);
244 clear_bit(US_FLIDX_TIMED_OUT
, &us
->flags
);
248 /* This invokes the transport reset mechanism to reset the state of the
250 /* This is always called with scsi_lock(host) held */
251 static int device_reset(struct scsi_cmnd
*srb
)
253 struct us_data
*us
= host_to_us(srb
->device
->host
);
256 US_DEBUGP("%s called\n", __FUNCTION__
);
258 scsi_unlock(us_to_host(us
));
260 /* lock the device pointers and do the reset */
261 down(&(us
->dev_semaphore
));
262 if (test_bit(US_FLIDX_DISCONNECTING
, &us
->flags
)) {
264 US_DEBUGP("No reset during disconnect\n");
266 result
= us
->transport_reset(us
);
267 up(&(us
->dev_semaphore
));
269 /* lock the host for the return */
270 scsi_lock(us_to_host(us
));
274 /* This resets the device's USB port. */
275 /* It refuses to work if there's more than one interface in
276 * the device, so that other users are not affected. */
277 /* This is always called with scsi_lock(host) held */
278 static int bus_reset(struct scsi_cmnd
*srb
)
280 struct us_data
*us
= host_to_us(srb
->device
->host
);
283 US_DEBUGP("%s called\n", __FUNCTION__
);
285 scsi_unlock(us_to_host(us
));
287 /* The USB subsystem doesn't handle synchronisation between
288 * a device's several drivers. Therefore we reset only devices
289 * with just one interface, which we of course own. */
291 down(&(us
->dev_semaphore
));
292 if (test_bit(US_FLIDX_DISCONNECTING
, &us
->flags
)) {
294 US_DEBUGP("No reset during disconnect\n");
295 } else if (us
->pusb_dev
->actconfig
->desc
.bNumInterfaces
!= 1) {
297 US_DEBUGP("Refusing to reset a multi-interface device\n");
299 rc
= usb_lock_device_for_reset(us
->pusb_dev
, us
->pusb_intf
);
301 US_DEBUGP("unable to lock device for reset: %d\n", rc
);
304 result
= usb_reset_device(us
->pusb_dev
);
306 usb_unlock_device(us
->pusb_dev
);
307 US_DEBUGP("usb_reset_device returns %d\n", result
);
310 up(&(us
->dev_semaphore
));
312 /* lock the host for the return */
313 scsi_lock(us_to_host(us
));
314 return result
< 0 ? FAILED
: SUCCESS
;
317 /* Report a driver-initiated device reset to the SCSI layer.
318 * Calling this for a SCSI-initiated reset is unnecessary but harmless.
319 * The caller must own the SCSI host lock. */
320 void usb_stor_report_device_reset(struct us_data
*us
)
323 struct Scsi_Host
*host
= us_to_host(us
);
325 scsi_report_device_reset(host
, 0, 0);
326 if (us
->flags
& US_FL_SCM_MULT_TARG
) {
327 for (i
= 1; i
< host
->max_id
; ++i
)
328 scsi_report_device_reset(host
, 0, i
);
332 /***********************************************************************
333 * /proc/scsi/ functions
334 ***********************************************************************/
336 /* we use this macro to help us write into the buffer */
338 #define SPRINTF(args...) \
339 do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)
341 static int proc_info (struct Scsi_Host
*host
, char *buffer
,
342 char **start
, off_t offset
, int length
, int inout
)
344 struct us_data
*us
= host_to_us(host
);
348 /* if someone is sending us data, just throw it away */
352 /* print the controller name */
353 SPRINTF(" Host scsi%d: usb-storage\n", host
->host_no
);
355 /* print product, vendor, and serial number strings */
356 if (us
->pusb_dev
->manufacturer
)
357 string
= us
->pusb_dev
->manufacturer
;
358 else if (us
->unusual_dev
->vendorName
)
359 string
= us
->unusual_dev
->vendorName
;
362 SPRINTF(" Vendor: %s\n", string
);
363 if (us
->pusb_dev
->product
)
364 string
= us
->pusb_dev
->product
;
365 else if (us
->unusual_dev
->productName
)
366 string
= us
->unusual_dev
->productName
;
369 SPRINTF(" Product: %s\n", string
);
370 if (us
->pusb_dev
->serial
)
371 string
= us
->pusb_dev
->serial
;
374 SPRINTF("Serial Number: %s\n", string
);
376 /* show the protocol and transport */
377 SPRINTF(" Protocol: %s\n", us
->protocol_name
);
378 SPRINTF(" Transport: %s\n", us
->transport_name
);
380 /* show the device flags */
381 if (pos
< buffer
+ length
) {
382 pos
+= sprintf(pos
, " Quirks:");
384 #define US_FLAG(name, value) \
385 if (us->flags & value) pos += sprintf(pos, " " #name);
393 * Calculate start of next buffer, and return value.
395 *start
= buffer
+ offset
;
397 if ((pos
- buffer
) < offset
)
399 else if ((pos
- buffer
- offset
) < length
)
400 return (pos
- buffer
- offset
);
405 /***********************************************************************
407 ***********************************************************************/
409 /* Output routine for the sysfs max_sectors file */
410 static ssize_t
show_max_sectors(struct device
*dev
, char *buf
)
412 struct scsi_device
*sdev
= to_scsi_device(dev
);
414 return sprintf(buf
, "%u\n", sdev
->request_queue
->max_sectors
);
417 /* Input routine for the sysfs max_sectors file */
418 static ssize_t
store_max_sectors(struct device
*dev
, const char *buf
,
421 struct scsi_device
*sdev
= to_scsi_device(dev
);
424 if (sscanf(buf
, "%hu", &ms
) > 0 && ms
<= SCSI_DEFAULT_MAX_SECTORS
) {
425 blk_queue_max_sectors(sdev
->request_queue
, ms
);
431 static DEVICE_ATTR(max_sectors
, S_IRUGO
| S_IWUSR
, show_max_sectors
,
434 static struct device_attribute
*sysfs_device_attr_list
[] = {
435 &dev_attr_max_sectors
,
440 * this defines our host template, with which we'll allocate hosts
443 struct scsi_host_template usb_stor_host_template
= {
444 /* basic userland interface stuff */
445 .name
= "usb-storage",
446 .proc_name
= "usb-storage",
447 .proc_info
= proc_info
,
450 /* command interface -- queued only */
451 .queuecommand
= queuecommand
,
453 /* error and abort handlers */
454 .eh_abort_handler
= command_abort
,
455 .eh_device_reset_handler
= device_reset
,
456 .eh_bus_reset_handler
= bus_reset
,
458 /* queue commands only, only one command per LUN */
462 /* unknown initiator id */
465 .slave_alloc
= slave_alloc
,
466 .slave_configure
= slave_configure
,
468 /* lots of sg segments can be handled */
469 .sg_tablesize
= SG_ALL
,
471 /* limit the total size of a transfer to 120 KB */
474 /* merge commands... this seems to help performance, but
475 * periodically someone should test to see which setting is more
483 /* we do our own delay after a device or bus reset */
484 .skip_settle_delay
= 1,
486 /* sysfs device attributes */
487 .sdev_attrs
= sysfs_device_attr_list
,
489 /* module management */
490 .module
= THIS_MODULE
493 /* To Report "Illegal Request: Invalid Field in CDB */
494 unsigned char usb_stor_sense_invalidCDB
[18] = {
495 [0] = 0x70, /* current error */
496 [2] = ILLEGAL_REQUEST
, /* Illegal Request = 0x05 */
497 [7] = 0x0a, /* additional length */
498 [12] = 0x24 /* Invalid Field in CDB */