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 /* assume SPC3 or latter devices support sense size > 18 */
174 if (sdev->scsi_level > SCSI_SPC_2)
175 us->fflags |= US_FL_SANE_SENSE;
177 /* Some devices report a SCSI revision level above 2 but are
178 * unable to handle the REPORT LUNS command (for which
179 * support is mandatory at level 3). Since we already have
180 * a Get-Max-LUN request, we won't lose much by setting the
181 * revision level down to 2. The only devices that would be
182 * affected are those with sparse LUNs. */
183 if (sdev->scsi_level > SCSI_2)
184 sdev->sdev_target->scsi_level =
185 sdev->scsi_level = SCSI_2;
187 /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
188 * Hardware Error) when any low-level error occurs,
189 * recoverable or not. Setting this flag tells the SCSI
190 * midlayer to retry such commands, which frequently will
191 * succeed and fix the error. The worst this can lead to
192 * is an occasional series of retries that will all fail. */
193 sdev->retry_hwerror = 1;
195 /* USB disks should allow restart. Some drives spin down
196 * automatically, requiring a START-STOP UNIT command. */
197 sdev->allow_restart = 1;
199 /* Some USB cardreaders have trouble reading an sdcard's last
200 * sector in a larger then 1 sector read, since the performance
201 * impact is negible we set this flag for all USB disks */
202 sdev->last_sector_bug = 1;
205 /* Non-disk-type devices don't need to blacklist any pages
206 * or to force 192-byte transfer lengths for MODE SENSE.
207 * But they do need to use MODE SENSE(10). */
208 sdev->use_10_for_ms = 1;
211 /* The CB and CBI transports have no way to pass LUN values
212 * other than the bits in the second byte of a CDB. But those
213 * bits don't get set to the LUN value if the device reports
214 * scsi_level == 0 (UNKNOWN). Hence such devices must necessarily
217 if ((us->protocol == US_PR_CB || us->protocol == US_PR_CBI) &&
218 sdev->scsi_level == SCSI_UNKNOWN)
221 /* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
222 * REMOVAL command, so suppress those commands. */
223 if (us->fflags & US_FL_NOT_LOCKABLE)
226 /* this is to satisfy the compiler, tho I don't think the
227 * return code is ever checked anywhere. */
231 /* queue a command */
232 /* This is always called with scsi_lock(host) held */
233 static int queuecommand(struct scsi_cmnd *srb,
234 void (*done)(struct scsi_cmnd *))
236 struct us_data *us = host_to_us(srb->device->host);
238 US_DEBUGP("%s called\n", __func__);
240 /* check for state-transition errors */
241 if (us->srb != NULL) {
242 printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n",
244 return SCSI_MLQUEUE_HOST_BUSY;
247 /* fail the command if we are disconnecting */
248 if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
249 US_DEBUGP("Fail command during disconnect\n");
250 srb->result = DID_NO_CONNECT << 16;
255 /* enqueue the command and wake up the control thread */
256 srb->scsi_done = done;
258 complete(&us->cmnd_ready);
263 /***********************************************************************
264 * Error handling functions
265 ***********************************************************************/
267 /* Command timeout and abort */
268 static int command_abort(struct scsi_cmnd *srb)
270 struct us_data *us = host_to_us(srb->device->host);
272 US_DEBUGP("%s called\n", __func__);
274 /* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
275 * bits are protected by the host lock. */
276 scsi_lock(us_to_host(us));
278 /* Is this command still active? */
279 if (us->srb != srb) {
280 scsi_unlock(us_to_host(us));
281 US_DEBUGP ("-- nothing to abort\n");
285 /* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if
286 * a device reset isn't already in progress (to avoid interfering
287 * with the reset). Note that we must retain the host lock while
288 * calling usb_stor_stop_transport(); otherwise it might interfere
289 * with an auto-reset that begins as soon as we release the lock. */
290 set_bit(US_FLIDX_TIMED_OUT, &us->dflags);
291 if (!test_bit(US_FLIDX_RESETTING, &us->dflags)) {
292 set_bit(US_FLIDX_ABORTING, &us->dflags);
293 usb_stor_stop_transport(us);
295 scsi_unlock(us_to_host(us));
297 /* Wait for the aborted command to finish */
298 wait_for_completion(&us->notify);
302 /* This invokes the transport reset mechanism to reset the state of the
304 static int device_reset(struct scsi_cmnd *srb)
306 struct us_data *us = host_to_us(srb->device->host);
309 US_DEBUGP("%s called\n", __func__);
311 /* lock the device pointers and do the reset */
312 mutex_lock(&(us->dev_mutex));
313 result = us->transport_reset(us);
314 mutex_unlock(&us->dev_mutex);
316 return result < 0 ? FAILED : SUCCESS;
319 /* Simulate a SCSI bus reset by resetting the device's USB port. */
320 static int bus_reset(struct scsi_cmnd *srb)
322 struct us_data *us = host_to_us(srb->device->host);
325 US_DEBUGP("%s called\n", __func__);
326 result = usb_stor_port_reset(us);
327 return result < 0 ? FAILED : SUCCESS;
330 /* Report a driver-initiated device reset to the SCSI layer.
331 * Calling this for a SCSI-initiated reset is unnecessary but harmless.
332 * The caller must own the SCSI host lock. */
333 void usb_stor_report_device_reset(struct us_data *us)
336 struct Scsi_Host *host = us_to_host(us);
338 scsi_report_device_reset(host, 0, 0);
339 if (us->fflags & US_FL_SCM_MULT_TARG) {
340 for (i = 1; i < host->max_id; ++i)
341 scsi_report_device_reset(host, 0, i);
345 /* Report a driver-initiated bus reset to the SCSI layer.
346 * Calling this for a SCSI-initiated reset is unnecessary but harmless.
347 * The caller must not own the SCSI host lock. */
348 void usb_stor_report_bus_reset(struct us_data *us)
350 struct Scsi_Host *host = us_to_host(us);
353 scsi_report_bus_reset(host, 0);
357 /***********************************************************************
358 * /proc/scsi/ functions
359 ***********************************************************************/
361 /* we use this macro to help us write into the buffer */
363 #define SPRINTF(args...) \
364 do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)
366 static int proc_info (struct Scsi_Host *host, char *buffer,
367 char **start, off_t offset, int length, int inout)
369 struct us_data *us = host_to_us(host);
373 /* if someone is sending us data, just throw it away */
377 /* print the controller name */
378 SPRINTF(" Host scsi%d: usb-storage\n", host->host_no);
380 /* print product, vendor, and serial number strings */
381 if (us->pusb_dev->manufacturer)
382 string = us->pusb_dev->manufacturer;
383 else if (us->unusual_dev->vendorName)
384 string = us->unusual_dev->vendorName;
387 SPRINTF(" Vendor: %s\n", string);
388 if (us->pusb_dev->product)
389 string = us->pusb_dev->product;
390 else if (us->unusual_dev->productName)
391 string = us->unusual_dev->productName;
394 SPRINTF(" Product: %s\n", string);
395 if (us->pusb_dev->serial)
396 string = us->pusb_dev->serial;
399 SPRINTF("Serial Number: %s\n", string);
401 /* show the protocol and transport */
402 SPRINTF(" Protocol: %s\n", us->protocol_name);
403 SPRINTF(" Transport: %s\n", us->transport_name);
405 /* show the device flags */
406 if (pos < buffer + length) {
407 pos += sprintf(pos, " Quirks:");
409 #define US_FLAG(name, value) \
410 if (us->fflags & value) pos += sprintf(pos, " " #name);
418 * Calculate start of next buffer, and return value.
420 *start = buffer + offset;
422 if ((pos - buffer) < offset)
424 else if ((pos - buffer - offset) < length)
425 return (pos - buffer - offset);
430 /***********************************************************************
432 ***********************************************************************/
434 /* Output routine for the sysfs max_sectors file */
435 static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf)
437 struct scsi_device *sdev = to_scsi_device(dev);
439 return sprintf(buf, "%u\n", sdev->request_queue->max_sectors);
442 /* Input routine for the sysfs max_sectors file */
443 static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf,
446 struct scsi_device *sdev = to_scsi_device(dev);
449 if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) {
450 blk_queue_max_sectors(sdev->request_queue, ms);
456 static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors,
459 static struct device_attribute *sysfs_device_attr_list[] = {
460 &dev_attr_max_sectors,
465 * this defines our host template, with which we'll allocate hosts
468 struct scsi_host_template usb_stor_host_template = {
469 /* basic userland interface stuff */
470 .name = "usb-storage",
471 .proc_name = "usb-storage",
472 .proc_info = proc_info,
475 /* command interface -- queued only */
476 .queuecommand = queuecommand,
478 /* error and abort handlers */
479 .eh_abort_handler = command_abort,
480 .eh_device_reset_handler = device_reset,
481 .eh_bus_reset_handler = bus_reset,
483 /* queue commands only, only one command per LUN */
487 /* unknown initiator id */
490 .slave_alloc = slave_alloc,
491 .slave_configure = slave_configure,
493 /* lots of sg segments can be handled */
494 .sg_tablesize = SG_ALL,
496 /* limit the total size of a transfer to 120 KB */
499 /* merge commands... this seems to help performance, but
500 * periodically someone should test to see which setting is more
508 /* we do our own delay after a device or bus reset */
509 .skip_settle_delay = 1,
511 /* sysfs device attributes */
512 .sdev_attrs = sysfs_device_attr_list,
514 /* module management */
515 .module = THIS_MODULE
518 /* To Report "Illegal Request: Invalid Field in CDB */
519 unsigned char usb_stor_sense_invalidCDB[18] = {
520 [0] = 0x70, /* current error */
521 [2] = ILLEGAL_REQUEST, /* Illegal Request = 0x05 */
522 [7] = 0x0a, /* additional length */
523 [12] = 0x24 /* Invalid Field in CDB */