xref: /openbmc/linux/drivers/usb/storage/transport.c (revision d78c317f)
1 /* Driver for USB Mass Storage compliant devices
2  *
3  * Current development and maintenance by:
4  *   (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
5  *
6  * Developed with the assistance of:
7  *   (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
8  *   (c) 2000 Stephen J. Gowdy (SGowdy@lbl.gov)
9  *   (c) 2002 Alan Stern <stern@rowland.org>
10  *
11  * Initial work by:
12  *   (c) 1999 Michael Gee (michael@linuxspecific.com)
13  *
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.
19  *
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.
24  *
25  * Also, for certain devices, the interrupt endpoint is used to convey
26  * status of a command.
27  *
28  * Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
29  * information about this driver.
30  *
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
34  * later version.
35  *
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.
40  *
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.
44  */
45 
46 #include <linux/sched.h>
47 #include <linux/gfp.h>
48 #include <linux/errno.h>
49 #include <linux/export.h>
50 
51 #include <linux/usb/quirks.h>
52 
53 #include <scsi/scsi.h>
54 #include <scsi/scsi_eh.h>
55 #include <scsi/scsi_device.h>
56 
57 #include "usb.h"
58 #include "transport.h"
59 #include "protocol.h"
60 #include "scsiglue.h"
61 #include "debug.h"
62 
63 #include <linux/blkdev.h>
64 #include "../../scsi/sd.h"
65 
66 
67 /***********************************************************************
68  * Data transfer routines
69  ***********************************************************************/
70 
71 /*
72  * This is subtle, so pay attention:
73  * ---------------------------------
74  * We're very concerned about races with a command abort.  Hanging this code
75  * is a sure fire way to hang the kernel.  (Note that this discussion applies
76  * only to transactions resulting from a scsi queued-command, since only
77  * these transactions are subject to a scsi abort.  Other transactions, such
78  * as those occurring during device-specific initialization, must be handled
79  * by a separate code path.)
80  *
81  * The abort function (usb_storage_command_abort() in scsiglue.c) first
82  * sets the machine state and the ABORTING bit in us->dflags to prevent
83  * new URBs from being submitted.  It then calls usb_stor_stop_transport()
84  * below, which atomically tests-and-clears the URB_ACTIVE bit in us->dflags
85  * to see if the current_urb needs to be stopped.  Likewise, the SG_ACTIVE
86  * bit is tested to see if the current_sg scatter-gather request needs to be
87  * stopped.  The timeout callback routine does much the same thing.
88  *
89  * When a disconnect occurs, the DISCONNECTING bit in us->dflags is set to
90  * prevent new URBs from being submitted, and usb_stor_stop_transport() is
91  * called to stop any ongoing requests.
92  *
93  * The submit function first verifies that the submitting is allowed
94  * (neither ABORTING nor DISCONNECTING bits are set) and that the submit
95  * completes without errors, and only then sets the URB_ACTIVE bit.  This
96  * prevents the stop_transport() function from trying to cancel the URB
97  * while the submit call is underway.  Next, the submit function must test
98  * the flags to see if an abort or disconnect occurred during the submission
99  * or before the URB_ACTIVE bit was set.  If so, it's essential to cancel
100  * the URB if it hasn't been cancelled already (i.e., if the URB_ACTIVE bit
101  * is still set).  Either way, the function must then wait for the URB to
102  * finish.  Note that the URB can still be in progress even after a call to
103  * usb_unlink_urb() returns.
104  *
105  * The idea is that (1) once the ABORTING or DISCONNECTING bit is set,
106  * either the stop_transport() function or the submitting function
107  * is guaranteed to call usb_unlink_urb() for an active URB,
108  * and (2) test_and_clear_bit() prevents usb_unlink_urb() from being
109  * called more than once or from being called during usb_submit_urb().
110  */
111 
112 /* This is the completion handler which will wake us up when an URB
113  * completes.
114  */
115 static void usb_stor_blocking_completion(struct urb *urb)
116 {
117 	struct completion *urb_done_ptr = urb->context;
118 
119 	complete(urb_done_ptr);
120 }
121 
122 /* This is the common part of the URB message submission code
123  *
124  * All URBs from the usb-storage driver involved in handling a queued scsi
125  * command _must_ pass through this function (or something like it) for the
126  * abort mechanisms to work properly.
127  */
128 static int usb_stor_msg_common(struct us_data *us, int timeout)
129 {
130 	struct completion urb_done;
131 	long timeleft;
132 	int status;
133 
134 	/* don't submit URBs during abort processing */
135 	if (test_bit(US_FLIDX_ABORTING, &us->dflags))
136 		return -EIO;
137 
138 	/* set up data structures for the wakeup system */
139 	init_completion(&urb_done);
140 
141 	/* fill the common fields in the URB */
142 	us->current_urb->context = &urb_done;
143 	us->current_urb->transfer_flags = 0;
144 
145 	/* we assume that if transfer_buffer isn't us->iobuf then it
146 	 * hasn't been mapped for DMA.  Yes, this is clunky, but it's
147 	 * easier than always having the caller tell us whether the
148 	 * transfer buffer has already been mapped. */
149 	if (us->current_urb->transfer_buffer == us->iobuf)
150 		us->current_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
151 	us->current_urb->transfer_dma = us->iobuf_dma;
152 
153 	/* submit the URB */
154 	status = usb_submit_urb(us->current_urb, GFP_NOIO);
155 	if (status) {
156 		/* something went wrong */
157 		return status;
158 	}
159 
160 	/* since the URB has been submitted successfully, it's now okay
161 	 * to cancel it */
162 	set_bit(US_FLIDX_URB_ACTIVE, &us->dflags);
163 
164 	/* did an abort occur during the submission? */
165 	if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
166 
167 		/* cancel the URB, if it hasn't been cancelled already */
168 		if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
169 			US_DEBUGP("-- cancelling URB\n");
170 			usb_unlink_urb(us->current_urb);
171 		}
172 	}
173 
174 	/* wait for the completion of the URB */
175 	timeleft = wait_for_completion_interruptible_timeout(
176 			&urb_done, timeout ? : MAX_SCHEDULE_TIMEOUT);
177 
178 	clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags);
179 
180 	if (timeleft <= 0) {
181 		US_DEBUGP("%s -- cancelling URB\n",
182 			  timeleft == 0 ? "Timeout" : "Signal");
183 		usb_kill_urb(us->current_urb);
184 	}
185 
186 	/* return the URB status */
187 	return us->current_urb->status;
188 }
189 
190 /*
191  * Transfer one control message, with timeouts, and allowing early
192  * termination.  Return codes are usual -Exxx, *not* USB_STOR_XFER_xxx.
193  */
194 int usb_stor_control_msg(struct us_data *us, unsigned int pipe,
195 		 u8 request, u8 requesttype, u16 value, u16 index,
196 		 void *data, u16 size, int timeout)
197 {
198 	int status;
199 
200 	US_DEBUGP("%s: rq=%02x rqtype=%02x value=%04x index=%02x len=%u\n",
201 			__func__, request, requesttype,
202 			value, index, size);
203 
204 	/* fill in the devrequest structure */
205 	us->cr->bRequestType = requesttype;
206 	us->cr->bRequest = request;
207 	us->cr->wValue = cpu_to_le16(value);
208 	us->cr->wIndex = cpu_to_le16(index);
209 	us->cr->wLength = cpu_to_le16(size);
210 
211 	/* fill and submit the URB */
212 	usb_fill_control_urb(us->current_urb, us->pusb_dev, pipe,
213 			 (unsigned char*) us->cr, data, size,
214 			 usb_stor_blocking_completion, NULL);
215 	status = usb_stor_msg_common(us, timeout);
216 
217 	/* return the actual length of the data transferred if no error */
218 	if (status == 0)
219 		status = us->current_urb->actual_length;
220 	return status;
221 }
222 EXPORT_SYMBOL_GPL(usb_stor_control_msg);
223 
224 /* This is a version of usb_clear_halt() that allows early termination and
225  * doesn't read the status from the device -- this is because some devices
226  * crash their internal firmware when the status is requested after a halt.
227  *
228  * A definitive list of these 'bad' devices is too difficult to maintain or
229  * make complete enough to be useful.  This problem was first observed on the
230  * Hagiwara FlashGate DUAL unit.  However, bus traces reveal that neither
231  * MacOS nor Windows checks the status after clearing a halt.
232  *
233  * Since many vendors in this space limit their testing to interoperability
234  * with these two OSes, specification violations like this one are common.
235  */
236 int usb_stor_clear_halt(struct us_data *us, unsigned int pipe)
237 {
238 	int result;
239 	int endp = usb_pipeendpoint(pipe);
240 
241 	if (usb_pipein (pipe))
242 		endp |= USB_DIR_IN;
243 
244 	result = usb_stor_control_msg(us, us->send_ctrl_pipe,
245 		USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT,
246 		USB_ENDPOINT_HALT, endp,
247 		NULL, 0, 3*HZ);
248 
249 	if (result >= 0)
250 		usb_reset_endpoint(us->pusb_dev, endp);
251 
252 	US_DEBUGP("%s: result = %d\n", __func__, result);
253 	return result;
254 }
255 EXPORT_SYMBOL_GPL(usb_stor_clear_halt);
256 
257 
258 /*
259  * Interpret the results of a URB transfer
260  *
261  * This function prints appropriate debugging messages, clears halts on
262  * non-control endpoints, and translates the status to the corresponding
263  * USB_STOR_XFER_xxx return code.
264  */
265 static int interpret_urb_result(struct us_data *us, unsigned int pipe,
266 		unsigned int length, int result, unsigned int partial)
267 {
268 	US_DEBUGP("Status code %d; transferred %u/%u\n",
269 			result, partial, length);
270 	switch (result) {
271 
272 	/* no error code; did we send all the data? */
273 	case 0:
274 		if (partial != length) {
275 			US_DEBUGP("-- short transfer\n");
276 			return USB_STOR_XFER_SHORT;
277 		}
278 
279 		US_DEBUGP("-- transfer complete\n");
280 		return USB_STOR_XFER_GOOD;
281 
282 	/* stalled */
283 	case -EPIPE:
284 		/* for control endpoints, (used by CB[I]) a stall indicates
285 		 * a failed command */
286 		if (usb_pipecontrol(pipe)) {
287 			US_DEBUGP("-- stall on control pipe\n");
288 			return USB_STOR_XFER_STALLED;
289 		}
290 
291 		/* for other sorts of endpoint, clear the stall */
292 		US_DEBUGP("clearing endpoint halt for pipe 0x%x\n", pipe);
293 		if (usb_stor_clear_halt(us, pipe) < 0)
294 			return USB_STOR_XFER_ERROR;
295 		return USB_STOR_XFER_STALLED;
296 
297 	/* babble - the device tried to send more than we wanted to read */
298 	case -EOVERFLOW:
299 		US_DEBUGP("-- babble\n");
300 		return USB_STOR_XFER_LONG;
301 
302 	/* the transfer was cancelled by abort, disconnect, or timeout */
303 	case -ECONNRESET:
304 		US_DEBUGP("-- transfer cancelled\n");
305 		return USB_STOR_XFER_ERROR;
306 
307 	/* short scatter-gather read transfer */
308 	case -EREMOTEIO:
309 		US_DEBUGP("-- short read transfer\n");
310 		return USB_STOR_XFER_SHORT;
311 
312 	/* abort or disconnect in progress */
313 	case -EIO:
314 		US_DEBUGP("-- abort or disconnect in progress\n");
315 		return USB_STOR_XFER_ERROR;
316 
317 	/* the catch-all error case */
318 	default:
319 		US_DEBUGP("-- unknown error\n");
320 		return USB_STOR_XFER_ERROR;
321 	}
322 }
323 
324 /*
325  * Transfer one control message, without timeouts, but allowing early
326  * termination.  Return codes are USB_STOR_XFER_xxx.
327  */
328 int usb_stor_ctrl_transfer(struct us_data *us, unsigned int pipe,
329 		u8 request, u8 requesttype, u16 value, u16 index,
330 		void *data, u16 size)
331 {
332 	int result;
333 
334 	US_DEBUGP("%s: rq=%02x rqtype=%02x value=%04x index=%02x len=%u\n",
335 			__func__, request, requesttype,
336 			value, index, size);
337 
338 	/* fill in the devrequest structure */
339 	us->cr->bRequestType = requesttype;
340 	us->cr->bRequest = request;
341 	us->cr->wValue = cpu_to_le16(value);
342 	us->cr->wIndex = cpu_to_le16(index);
343 	us->cr->wLength = cpu_to_le16(size);
344 
345 	/* fill and submit the URB */
346 	usb_fill_control_urb(us->current_urb, us->pusb_dev, pipe,
347 			 (unsigned char*) us->cr, data, size,
348 			 usb_stor_blocking_completion, NULL);
349 	result = usb_stor_msg_common(us, 0);
350 
351 	return interpret_urb_result(us, pipe, size, result,
352 			us->current_urb->actual_length);
353 }
354 EXPORT_SYMBOL_GPL(usb_stor_ctrl_transfer);
355 
356 /*
357  * Receive one interrupt buffer, without timeouts, but allowing early
358  * termination.  Return codes are USB_STOR_XFER_xxx.
359  *
360  * This routine always uses us->recv_intr_pipe as the pipe and
361  * us->ep_bInterval as the interrupt interval.
362  */
363 static int usb_stor_intr_transfer(struct us_data *us, void *buf,
364 				  unsigned int length)
365 {
366 	int result;
367 	unsigned int pipe = us->recv_intr_pipe;
368 	unsigned int maxp;
369 
370 	US_DEBUGP("%s: xfer %u bytes\n", __func__, length);
371 
372 	/* calculate the max packet size */
373 	maxp = usb_maxpacket(us->pusb_dev, pipe, usb_pipeout(pipe));
374 	if (maxp > length)
375 		maxp = length;
376 
377 	/* fill and submit the URB */
378 	usb_fill_int_urb(us->current_urb, us->pusb_dev, pipe, buf,
379 			maxp, usb_stor_blocking_completion, NULL,
380 			us->ep_bInterval);
381 	result = usb_stor_msg_common(us, 0);
382 
383 	return interpret_urb_result(us, pipe, length, result,
384 			us->current_urb->actual_length);
385 }
386 
387 /*
388  * Transfer one buffer via bulk pipe, without timeouts, but allowing early
389  * termination.  Return codes are USB_STOR_XFER_xxx.  If the bulk pipe
390  * stalls during the transfer, the halt is automatically cleared.
391  */
392 int usb_stor_bulk_transfer_buf(struct us_data *us, unsigned int pipe,
393 	void *buf, unsigned int length, unsigned int *act_len)
394 {
395 	int result;
396 
397 	US_DEBUGP("%s: xfer %u bytes\n", __func__, length);
398 
399 	/* fill and submit the URB */
400 	usb_fill_bulk_urb(us->current_urb, us->pusb_dev, pipe, buf, length,
401 		      usb_stor_blocking_completion, NULL);
402 	result = usb_stor_msg_common(us, 0);
403 
404 	/* store the actual length of the data transferred */
405 	if (act_len)
406 		*act_len = us->current_urb->actual_length;
407 	return interpret_urb_result(us, pipe, length, result,
408 			us->current_urb->actual_length);
409 }
410 EXPORT_SYMBOL_GPL(usb_stor_bulk_transfer_buf);
411 
412 /*
413  * Transfer a scatter-gather list via bulk transfer
414  *
415  * This function does basically the same thing as usb_stor_bulk_transfer_buf()
416  * above, but it uses the usbcore scatter-gather library.
417  */
418 static int usb_stor_bulk_transfer_sglist(struct us_data *us, unsigned int pipe,
419 		struct scatterlist *sg, int num_sg, unsigned int length,
420 		unsigned int *act_len)
421 {
422 	int result;
423 
424 	/* don't submit s-g requests during abort processing */
425 	if (test_bit(US_FLIDX_ABORTING, &us->dflags))
426 		return USB_STOR_XFER_ERROR;
427 
428 	/* initialize the scatter-gather request block */
429 	US_DEBUGP("%s: xfer %u bytes, %d entries\n", __func__,
430 			length, num_sg);
431 	result = usb_sg_init(&us->current_sg, us->pusb_dev, pipe, 0,
432 			sg, num_sg, length, GFP_NOIO);
433 	if (result) {
434 		US_DEBUGP("usb_sg_init returned %d\n", result);
435 		return USB_STOR_XFER_ERROR;
436 	}
437 
438 	/* since the block has been initialized successfully, it's now
439 	 * okay to cancel it */
440 	set_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
441 
442 	/* did an abort occur during the submission? */
443 	if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
444 
445 		/* cancel the request, if it hasn't been cancelled already */
446 		if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
447 			US_DEBUGP("-- cancelling sg request\n");
448 			usb_sg_cancel(&us->current_sg);
449 		}
450 	}
451 
452 	/* wait for the completion of the transfer */
453 	usb_sg_wait(&us->current_sg);
454 	clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
455 
456 	result = us->current_sg.status;
457 	if (act_len)
458 		*act_len = us->current_sg.bytes;
459 	return interpret_urb_result(us, pipe, length, result,
460 			us->current_sg.bytes);
461 }
462 
463 /*
464  * Common used function. Transfer a complete command
465  * via usb_stor_bulk_transfer_sglist() above. Set cmnd resid
466  */
467 int usb_stor_bulk_srb(struct us_data* us, unsigned int pipe,
468 		      struct scsi_cmnd* srb)
469 {
470 	unsigned int partial;
471 	int result = usb_stor_bulk_transfer_sglist(us, pipe, scsi_sglist(srb),
472 				      scsi_sg_count(srb), scsi_bufflen(srb),
473 				      &partial);
474 
475 	scsi_set_resid(srb, scsi_bufflen(srb) - partial);
476 	return result;
477 }
478 EXPORT_SYMBOL_GPL(usb_stor_bulk_srb);
479 
480 /*
481  * Transfer an entire SCSI command's worth of data payload over the bulk
482  * pipe.
483  *
484  * Note that this uses usb_stor_bulk_transfer_buf() and
485  * usb_stor_bulk_transfer_sglist() to achieve its goals --
486  * this function simply determines whether we're going to use
487  * scatter-gather or not, and acts appropriately.
488  */
489 int usb_stor_bulk_transfer_sg(struct us_data* us, unsigned int pipe,
490 		void *buf, unsigned int length_left, int use_sg, int *residual)
491 {
492 	int result;
493 	unsigned int partial;
494 
495 	/* are we scatter-gathering? */
496 	if (use_sg) {
497 		/* use the usb core scatter-gather primitives */
498 		result = usb_stor_bulk_transfer_sglist(us, pipe,
499 				(struct scatterlist *) buf, use_sg,
500 				length_left, &partial);
501 		length_left -= partial;
502 	} else {
503 		/* no scatter-gather, just make the request */
504 		result = usb_stor_bulk_transfer_buf(us, pipe, buf,
505 				length_left, &partial);
506 		length_left -= partial;
507 	}
508 
509 	/* store the residual and return the error code */
510 	if (residual)
511 		*residual = length_left;
512 	return result;
513 }
514 EXPORT_SYMBOL_GPL(usb_stor_bulk_transfer_sg);
515 
516 /***********************************************************************
517  * Transport routines
518  ***********************************************************************/
519 
520 /* There are so many devices that report the capacity incorrectly,
521  * this routine was written to counteract some of the resulting
522  * problems.
523  */
524 static void last_sector_hacks(struct us_data *us, struct scsi_cmnd *srb)
525 {
526 	struct gendisk *disk;
527 	struct scsi_disk *sdkp;
528 	u32 sector;
529 
530 	/* To Report "Medium Error: Record Not Found */
531 	static unsigned char record_not_found[18] = {
532 		[0]	= 0x70,			/* current error */
533 		[2]	= MEDIUM_ERROR,		/* = 0x03 */
534 		[7]	= 0x0a,			/* additional length */
535 		[12]	= 0x14			/* Record Not Found */
536 	};
537 
538 	/* If last-sector problems can't occur, whether because the
539 	 * capacity was already decremented or because the device is
540 	 * known to report the correct capacity, then we don't need
541 	 * to do anything.
542 	 */
543 	if (!us->use_last_sector_hacks)
544 		return;
545 
546 	/* Was this command a READ(10) or a WRITE(10)? */
547 	if (srb->cmnd[0] != READ_10 && srb->cmnd[0] != WRITE_10)
548 		goto done;
549 
550 	/* Did this command access the last sector? */
551 	sector = (srb->cmnd[2] << 24) | (srb->cmnd[3] << 16) |
552 			(srb->cmnd[4] << 8) | (srb->cmnd[5]);
553 	disk = srb->request->rq_disk;
554 	if (!disk)
555 		goto done;
556 	sdkp = scsi_disk(disk);
557 	if (!sdkp)
558 		goto done;
559 	if (sector + 1 != sdkp->capacity)
560 		goto done;
561 
562 	if (srb->result == SAM_STAT_GOOD && scsi_get_resid(srb) == 0) {
563 
564 		/* The command succeeded.  We know this device doesn't
565 		 * have the last-sector bug, so stop checking it.
566 		 */
567 		us->use_last_sector_hacks = 0;
568 
569 	} else {
570 		/* The command failed.  Allow up to 3 retries in case this
571 		 * is some normal sort of failure.  After that, assume the
572 		 * capacity is wrong and we're trying to access the sector
573 		 * beyond the end.  Replace the result code and sense data
574 		 * with values that will cause the SCSI core to fail the
575 		 * command immediately, instead of going into an infinite
576 		 * (or even just a very long) retry loop.
577 		 */
578 		if (++us->last_sector_retries < 3)
579 			return;
580 		srb->result = SAM_STAT_CHECK_CONDITION;
581 		memcpy(srb->sense_buffer, record_not_found,
582 				sizeof(record_not_found));
583 	}
584 
585  done:
586 	/* Don't reset the retry counter for TEST UNIT READY commands,
587 	 * because they get issued after device resets which might be
588 	 * caused by a failed last-sector access.
589 	 */
590 	if (srb->cmnd[0] != TEST_UNIT_READY)
591 		us->last_sector_retries = 0;
592 }
593 
594 /* Invoke the transport and basic error-handling/recovery methods
595  *
596  * This is used by the protocol layers to actually send the message to
597  * the device and receive the response.
598  */
599 void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
600 {
601 	int need_auto_sense;
602 	int result;
603 
604 	/* send the command to the transport layer */
605 	scsi_set_resid(srb, 0);
606 	result = us->transport(srb, us);
607 
608 	/* if the command gets aborted by the higher layers, we need to
609 	 * short-circuit all other processing
610 	 */
611 	if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
612 		US_DEBUGP("-- command was aborted\n");
613 		srb->result = DID_ABORT << 16;
614 		goto Handle_Errors;
615 	}
616 
617 	/* if there is a transport error, reset and don't auto-sense */
618 	if (result == USB_STOR_TRANSPORT_ERROR) {
619 		US_DEBUGP("-- transport indicates error, resetting\n");
620 		srb->result = DID_ERROR << 16;
621 		goto Handle_Errors;
622 	}
623 
624 	/* if the transport provided its own sense data, don't auto-sense */
625 	if (result == USB_STOR_TRANSPORT_NO_SENSE) {
626 		srb->result = SAM_STAT_CHECK_CONDITION;
627 		last_sector_hacks(us, srb);
628 		return;
629 	}
630 
631 	srb->result = SAM_STAT_GOOD;
632 
633 	/* Determine if we need to auto-sense
634 	 *
635 	 * I normally don't use a flag like this, but it's almost impossible
636 	 * to understand what's going on here if I don't.
637 	 */
638 	need_auto_sense = 0;
639 
640 	/*
641 	 * If we're running the CB transport, which is incapable
642 	 * of determining status on its own, we will auto-sense
643 	 * unless the operation involved a data-in transfer.  Devices
644 	 * can signal most data-in errors by stalling the bulk-in pipe.
645 	 */
646 	if ((us->protocol == USB_PR_CB || us->protocol == USB_PR_DPCM_USB) &&
647 			srb->sc_data_direction != DMA_FROM_DEVICE) {
648 		US_DEBUGP("-- CB transport device requiring auto-sense\n");
649 		need_auto_sense = 1;
650 	}
651 
652 	/*
653 	 * If we have a failure, we're going to do a REQUEST_SENSE
654 	 * automatically.  Note that we differentiate between a command
655 	 * "failure" and an "error" in the transport mechanism.
656 	 */
657 	if (result == USB_STOR_TRANSPORT_FAILED) {
658 		US_DEBUGP("-- transport indicates command failure\n");
659 		need_auto_sense = 1;
660 	}
661 
662 	/*
663 	 * Determine if this device is SAT by seeing if the
664 	 * command executed successfully.  Otherwise we'll have
665 	 * to wait for at least one CHECK_CONDITION to determine
666 	 * SANE_SENSE support
667 	 */
668 	if (unlikely((srb->cmnd[0] == ATA_16 || srb->cmnd[0] == ATA_12) &&
669 	    result == USB_STOR_TRANSPORT_GOOD &&
670 	    !(us->fflags & US_FL_SANE_SENSE) &&
671 	    !(us->fflags & US_FL_BAD_SENSE) &&
672 	    !(srb->cmnd[2] & 0x20))) {
673 		US_DEBUGP("-- SAT supported, increasing auto-sense\n");
674 		us->fflags |= US_FL_SANE_SENSE;
675 	}
676 
677 	/*
678 	 * A short transfer on a command where we don't expect it
679 	 * is unusual, but it doesn't mean we need to auto-sense.
680 	 */
681 	if ((scsi_get_resid(srb) > 0) &&
682 	    !((srb->cmnd[0] == REQUEST_SENSE) ||
683 	      (srb->cmnd[0] == INQUIRY) ||
684 	      (srb->cmnd[0] == MODE_SENSE) ||
685 	      (srb->cmnd[0] == LOG_SENSE) ||
686 	      (srb->cmnd[0] == MODE_SENSE_10))) {
687 		US_DEBUGP("-- unexpectedly short transfer\n");
688 	}
689 
690 	/* Now, if we need to do the auto-sense, let's do it */
691 	if (need_auto_sense) {
692 		int temp_result;
693 		struct scsi_eh_save ses;
694 		int sense_size = US_SENSE_SIZE;
695 		struct scsi_sense_hdr sshdr;
696 		const u8 *scdd;
697 		u8 fm_ili;
698 
699 		/* device supports and needs bigger sense buffer */
700 		if (us->fflags & US_FL_SANE_SENSE)
701 			sense_size = ~0;
702 Retry_Sense:
703 		US_DEBUGP("Issuing auto-REQUEST_SENSE\n");
704 
705 		scsi_eh_prep_cmnd(srb, &ses, NULL, 0, sense_size);
706 
707 		/* FIXME: we must do the protocol translation here */
708 		if (us->subclass == USB_SC_RBC || us->subclass == USB_SC_SCSI ||
709 				us->subclass == USB_SC_CYP_ATACB)
710 			srb->cmd_len = 6;
711 		else
712 			srb->cmd_len = 12;
713 
714 		/* issue the auto-sense command */
715 		scsi_set_resid(srb, 0);
716 		temp_result = us->transport(us->srb, us);
717 
718 		/* let's clean up right away */
719 		scsi_eh_restore_cmnd(srb, &ses);
720 
721 		if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
722 			US_DEBUGP("-- auto-sense aborted\n");
723 			srb->result = DID_ABORT << 16;
724 
725 			/* If SANE_SENSE caused this problem, disable it */
726 			if (sense_size != US_SENSE_SIZE) {
727 				us->fflags &= ~US_FL_SANE_SENSE;
728 				us->fflags |= US_FL_BAD_SENSE;
729 			}
730 			goto Handle_Errors;
731 		}
732 
733 		/* Some devices claim to support larger sense but fail when
734 		 * trying to request it. When a transport failure happens
735 		 * using US_FS_SANE_SENSE, we always retry with a standard
736 		 * (small) sense request. This fixes some USB GSM modems
737 		 */
738 		if (temp_result == USB_STOR_TRANSPORT_FAILED &&
739 				sense_size != US_SENSE_SIZE) {
740 			US_DEBUGP("-- auto-sense failure, retry small sense\n");
741 			sense_size = US_SENSE_SIZE;
742 			us->fflags &= ~US_FL_SANE_SENSE;
743 			us->fflags |= US_FL_BAD_SENSE;
744 			goto Retry_Sense;
745 		}
746 
747 		/* Other failures */
748 		if (temp_result != USB_STOR_TRANSPORT_GOOD) {
749 			US_DEBUGP("-- auto-sense failure\n");
750 
751 			/* we skip the reset if this happens to be a
752 			 * multi-target device, since failure of an
753 			 * auto-sense is perfectly valid
754 			 */
755 			srb->result = DID_ERROR << 16;
756 			if (!(us->fflags & US_FL_SCM_MULT_TARG))
757 				goto Handle_Errors;
758 			return;
759 		}
760 
761 		/* If the sense data returned is larger than 18-bytes then we
762 		 * assume this device supports requesting more in the future.
763 		 * The response code must be 70h through 73h inclusive.
764 		 */
765 		if (srb->sense_buffer[7] > (US_SENSE_SIZE - 8) &&
766 		    !(us->fflags & US_FL_SANE_SENSE) &&
767 		    !(us->fflags & US_FL_BAD_SENSE) &&
768 		    (srb->sense_buffer[0] & 0x7C) == 0x70) {
769 			US_DEBUGP("-- SANE_SENSE support enabled\n");
770 			us->fflags |= US_FL_SANE_SENSE;
771 
772 			/* Indicate to the user that we truncated their sense
773 			 * because we didn't know it supported larger sense.
774 			 */
775 			US_DEBUGP("-- Sense data truncated to %i from %i\n",
776 			          US_SENSE_SIZE,
777 			          srb->sense_buffer[7] + 8);
778 			srb->sense_buffer[7] = (US_SENSE_SIZE - 8);
779 		}
780 
781 		scsi_normalize_sense(srb->sense_buffer, SCSI_SENSE_BUFFERSIZE,
782 				     &sshdr);
783 
784 		US_DEBUGP("-- Result from auto-sense is %d\n", temp_result);
785 		US_DEBUGP("-- code: 0x%x, key: 0x%x, ASC: 0x%x, ASCQ: 0x%x\n",
786 			  sshdr.response_code, sshdr.sense_key,
787 			  sshdr.asc, sshdr.ascq);
788 #ifdef CONFIG_USB_STORAGE_DEBUG
789 		usb_stor_show_sense(sshdr.sense_key, sshdr.asc, sshdr.ascq);
790 #endif
791 
792 		/* set the result so the higher layers expect this data */
793 		srb->result = SAM_STAT_CHECK_CONDITION;
794 
795 		scdd = scsi_sense_desc_find(srb->sense_buffer,
796 					    SCSI_SENSE_BUFFERSIZE, 4);
797 		fm_ili = (scdd ? scdd[3] : srb->sense_buffer[2]) & 0xA0;
798 
799 		/* We often get empty sense data.  This could indicate that
800 		 * everything worked or that there was an unspecified
801 		 * problem.  We have to decide which.
802 		 */
803 		if (sshdr.sense_key == 0 && sshdr.asc == 0 && sshdr.ascq == 0 &&
804 		    fm_ili == 0) {
805 			/* If things are really okay, then let's show that.
806 			 * Zero out the sense buffer so the higher layers
807 			 * won't realize we did an unsolicited auto-sense.
808 			 */
809 			if (result == USB_STOR_TRANSPORT_GOOD) {
810 				srb->result = SAM_STAT_GOOD;
811 				srb->sense_buffer[0] = 0x0;
812 
813 			/* If there was a problem, report an unspecified
814 			 * hardware error to prevent the higher layers from
815 			 * entering an infinite retry loop.
816 			 */
817 			} else {
818 				srb->result = DID_ERROR << 16;
819 				if ((sshdr.response_code & 0x72) == 0x72)
820 					srb->sense_buffer[1] = HARDWARE_ERROR;
821 				else
822 					srb->sense_buffer[2] = HARDWARE_ERROR;
823 			}
824 		}
825 	}
826 
827 	/*
828 	 * Some devices don't work or return incorrect data the first
829 	 * time they get a READ(10) command, or for the first READ(10)
830 	 * after a media change.  If the INITIAL_READ10 flag is set,
831 	 * keep track of whether READ(10) commands succeed.  If the
832 	 * previous one succeeded and this one failed, set the REDO_READ10
833 	 * flag to force a retry.
834 	 */
835 	if (unlikely((us->fflags & US_FL_INITIAL_READ10) &&
836 			srb->cmnd[0] == READ_10)) {
837 		if (srb->result == SAM_STAT_GOOD) {
838 			set_bit(US_FLIDX_READ10_WORKED, &us->dflags);
839 		} else if (test_bit(US_FLIDX_READ10_WORKED, &us->dflags)) {
840 			clear_bit(US_FLIDX_READ10_WORKED, &us->dflags);
841 			set_bit(US_FLIDX_REDO_READ10, &us->dflags);
842 		}
843 
844 		/*
845 		 * Next, if the REDO_READ10 flag is set, return a result
846 		 * code that will cause the SCSI core to retry the READ(10)
847 		 * command immediately.
848 		 */
849 		if (test_bit(US_FLIDX_REDO_READ10, &us->dflags)) {
850 			clear_bit(US_FLIDX_REDO_READ10, &us->dflags);
851 			srb->result = DID_IMM_RETRY << 16;
852 			srb->sense_buffer[0] = 0;
853 		}
854 	}
855 
856 	/* Did we transfer less than the minimum amount required? */
857 	if ((srb->result == SAM_STAT_GOOD || srb->sense_buffer[2] == 0) &&
858 			scsi_bufflen(srb) - scsi_get_resid(srb) < srb->underflow)
859 		srb->result = DID_ERROR << 16;
860 
861 	last_sector_hacks(us, srb);
862 	return;
863 
864 	/* Error and abort processing: try to resynchronize with the device
865 	 * by issuing a port reset.  If that fails, try a class-specific
866 	 * device reset. */
867   Handle_Errors:
868 
869 	/* Set the RESETTING bit, and clear the ABORTING bit so that
870 	 * the reset may proceed. */
871 	scsi_lock(us_to_host(us));
872 	set_bit(US_FLIDX_RESETTING, &us->dflags);
873 	clear_bit(US_FLIDX_ABORTING, &us->dflags);
874 	scsi_unlock(us_to_host(us));
875 
876 	/* We must release the device lock because the pre_reset routine
877 	 * will want to acquire it. */
878 	mutex_unlock(&us->dev_mutex);
879 	result = usb_stor_port_reset(us);
880 	mutex_lock(&us->dev_mutex);
881 
882 	if (result < 0) {
883 		scsi_lock(us_to_host(us));
884 		usb_stor_report_device_reset(us);
885 		scsi_unlock(us_to_host(us));
886 		us->transport_reset(us);
887 	}
888 	clear_bit(US_FLIDX_RESETTING, &us->dflags);
889 	last_sector_hacks(us, srb);
890 }
891 
892 /* Stop the current URB transfer */
893 void usb_stor_stop_transport(struct us_data *us)
894 {
895 	US_DEBUGP("%s called\n", __func__);
896 
897 	/* If the state machine is blocked waiting for an URB,
898 	 * let's wake it up.  The test_and_clear_bit() call
899 	 * guarantees that if a URB has just been submitted,
900 	 * it won't be cancelled more than once. */
901 	if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
902 		US_DEBUGP("-- cancelling URB\n");
903 		usb_unlink_urb(us->current_urb);
904 	}
905 
906 	/* If we are waiting for a scatter-gather operation, cancel it. */
907 	if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
908 		US_DEBUGP("-- cancelling sg request\n");
909 		usb_sg_cancel(&us->current_sg);
910 	}
911 }
912 
913 /*
914  * Control/Bulk and Control/Bulk/Interrupt transport
915  */
916 
917 int usb_stor_CB_transport(struct scsi_cmnd *srb, struct us_data *us)
918 {
919 	unsigned int transfer_length = scsi_bufflen(srb);
920 	unsigned int pipe = 0;
921 	int result;
922 
923 	/* COMMAND STAGE */
924 	/* let's send the command via the control pipe */
925 	result = usb_stor_ctrl_transfer(us, us->send_ctrl_pipe,
926 				      US_CBI_ADSC,
927 				      USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0,
928 				      us->ifnum, srb->cmnd, srb->cmd_len);
929 
930 	/* check the return code for the command */
931 	US_DEBUGP("Call to usb_stor_ctrl_transfer() returned %d\n", result);
932 
933 	/* if we stalled the command, it means command failed */
934 	if (result == USB_STOR_XFER_STALLED) {
935 		return USB_STOR_TRANSPORT_FAILED;
936 	}
937 
938 	/* Uh oh... serious problem here */
939 	if (result != USB_STOR_XFER_GOOD) {
940 		return USB_STOR_TRANSPORT_ERROR;
941 	}
942 
943 	/* DATA STAGE */
944 	/* transfer the data payload for this command, if one exists*/
945 	if (transfer_length) {
946 		pipe = srb->sc_data_direction == DMA_FROM_DEVICE ?
947 				us->recv_bulk_pipe : us->send_bulk_pipe;
948 		result = usb_stor_bulk_srb(us, pipe, srb);
949 		US_DEBUGP("CBI data stage result is 0x%x\n", result);
950 
951 		/* if we stalled the data transfer it means command failed */
952 		if (result == USB_STOR_XFER_STALLED)
953 			return USB_STOR_TRANSPORT_FAILED;
954 		if (result > USB_STOR_XFER_STALLED)
955 			return USB_STOR_TRANSPORT_ERROR;
956 	}
957 
958 	/* STATUS STAGE */
959 
960 	/* NOTE: CB does not have a status stage.  Silly, I know.  So
961 	 * we have to catch this at a higher level.
962 	 */
963 	if (us->protocol != USB_PR_CBI)
964 		return USB_STOR_TRANSPORT_GOOD;
965 
966 	result = usb_stor_intr_transfer(us, us->iobuf, 2);
967 	US_DEBUGP("Got interrupt data (0x%x, 0x%x)\n",
968 			us->iobuf[0], us->iobuf[1]);
969 	if (result != USB_STOR_XFER_GOOD)
970 		return USB_STOR_TRANSPORT_ERROR;
971 
972 	/* UFI gives us ASC and ASCQ, like a request sense
973 	 *
974 	 * REQUEST_SENSE and INQUIRY don't affect the sense data on UFI
975 	 * devices, so we ignore the information for those commands.  Note
976 	 * that this means we could be ignoring a real error on these
977 	 * commands, but that can't be helped.
978 	 */
979 	if (us->subclass == USB_SC_UFI) {
980 		if (srb->cmnd[0] == REQUEST_SENSE ||
981 		    srb->cmnd[0] == INQUIRY)
982 			return USB_STOR_TRANSPORT_GOOD;
983 		if (us->iobuf[0])
984 			goto Failed;
985 		return USB_STOR_TRANSPORT_GOOD;
986 	}
987 
988 	/* If not UFI, we interpret the data as a result code
989 	 * The first byte should always be a 0x0.
990 	 *
991 	 * Some bogus devices don't follow that rule.  They stuff the ASC
992 	 * into the first byte -- so if it's non-zero, call it a failure.
993 	 */
994 	if (us->iobuf[0]) {
995 		US_DEBUGP("CBI IRQ data showed reserved bType 0x%x\n",
996 				us->iobuf[0]);
997 		goto Failed;
998 
999 	}
1000 
1001 	/* The second byte & 0x0F should be 0x0 for good, otherwise error */
1002 	switch (us->iobuf[1] & 0x0F) {
1003 		case 0x00:
1004 			return USB_STOR_TRANSPORT_GOOD;
1005 		case 0x01:
1006 			goto Failed;
1007 	}
1008 	return USB_STOR_TRANSPORT_ERROR;
1009 
1010 	/* the CBI spec requires that the bulk pipe must be cleared
1011 	 * following any data-in/out command failure (section 2.4.3.1.3)
1012 	 */
1013   Failed:
1014 	if (pipe)
1015 		usb_stor_clear_halt(us, pipe);
1016 	return USB_STOR_TRANSPORT_FAILED;
1017 }
1018 EXPORT_SYMBOL_GPL(usb_stor_CB_transport);
1019 
1020 /*
1021  * Bulk only transport
1022  */
1023 
1024 /* Determine what the maximum LUN supported is */
1025 int usb_stor_Bulk_max_lun(struct us_data *us)
1026 {
1027 	int result;
1028 
1029 	/* issue the command */
1030 	us->iobuf[0] = 0;
1031 	result = usb_stor_control_msg(us, us->recv_ctrl_pipe,
1032 				 US_BULK_GET_MAX_LUN,
1033 				 USB_DIR_IN | USB_TYPE_CLASS |
1034 				 USB_RECIP_INTERFACE,
1035 				 0, us->ifnum, us->iobuf, 1, 10*HZ);
1036 
1037 	US_DEBUGP("GetMaxLUN command result is %d, data is %d\n",
1038 		  result, us->iobuf[0]);
1039 
1040 	/* if we have a successful request, return the result */
1041 	if (result > 0)
1042 		return us->iobuf[0];
1043 
1044 	/*
1045 	 * Some devices don't like GetMaxLUN.  They may STALL the control
1046 	 * pipe, they may return a zero-length result, they may do nothing at
1047 	 * all and timeout, or they may fail in even more bizarrely creative
1048 	 * ways.  In these cases the best approach is to use the default
1049 	 * value: only one LUN.
1050 	 */
1051 	return 0;
1052 }
1053 
1054 int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us)
1055 {
1056 	struct bulk_cb_wrap *bcb = (struct bulk_cb_wrap *) us->iobuf;
1057 	struct bulk_cs_wrap *bcs = (struct bulk_cs_wrap *) us->iobuf;
1058 	unsigned int transfer_length = scsi_bufflen(srb);
1059 	unsigned int residue;
1060 	int result;
1061 	int fake_sense = 0;
1062 	unsigned int cswlen;
1063 	unsigned int cbwlen = US_BULK_CB_WRAP_LEN;
1064 
1065 	/* Take care of BULK32 devices; set extra byte to 0 */
1066 	if (unlikely(us->fflags & US_FL_BULK32)) {
1067 		cbwlen = 32;
1068 		us->iobuf[31] = 0;
1069 	}
1070 
1071 	/* set up the command wrapper */
1072 	bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
1073 	bcb->DataTransferLength = cpu_to_le32(transfer_length);
1074 	bcb->Flags = srb->sc_data_direction == DMA_FROM_DEVICE ? 1 << 7 : 0;
1075 	bcb->Tag = ++us->tag;
1076 	bcb->Lun = srb->device->lun;
1077 	if (us->fflags & US_FL_SCM_MULT_TARG)
1078 		bcb->Lun |= srb->device->id << 4;
1079 	bcb->Length = srb->cmd_len;
1080 
1081 	/* copy the command payload */
1082 	memset(bcb->CDB, 0, sizeof(bcb->CDB));
1083 	memcpy(bcb->CDB, srb->cmnd, bcb->Length);
1084 
1085 	/* send it to out endpoint */
1086 	US_DEBUGP("Bulk Command S 0x%x T 0x%x L %d F %d Trg %d LUN %d CL %d\n",
1087 			le32_to_cpu(bcb->Signature), bcb->Tag,
1088 			le32_to_cpu(bcb->DataTransferLength), bcb->Flags,
1089 			(bcb->Lun >> 4), (bcb->Lun & 0x0F),
1090 			bcb->Length);
1091 	result = usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
1092 				bcb, cbwlen, NULL);
1093 	US_DEBUGP("Bulk command transfer result=%d\n", result);
1094 	if (result != USB_STOR_XFER_GOOD)
1095 		return USB_STOR_TRANSPORT_ERROR;
1096 
1097 	/* DATA STAGE */
1098 	/* send/receive data payload, if there is any */
1099 
1100 	/* Some USB-IDE converter chips need a 100us delay between the
1101 	 * command phase and the data phase.  Some devices need a little
1102 	 * more than that, probably because of clock rate inaccuracies. */
1103 	if (unlikely(us->fflags & US_FL_GO_SLOW))
1104 		udelay(125);
1105 
1106 	if (transfer_length) {
1107 		unsigned int pipe = srb->sc_data_direction == DMA_FROM_DEVICE ?
1108 				us->recv_bulk_pipe : us->send_bulk_pipe;
1109 		result = usb_stor_bulk_srb(us, pipe, srb);
1110 		US_DEBUGP("Bulk data transfer result 0x%x\n", result);
1111 		if (result == USB_STOR_XFER_ERROR)
1112 			return USB_STOR_TRANSPORT_ERROR;
1113 
1114 		/* If the device tried to send back more data than the
1115 		 * amount requested, the spec requires us to transfer
1116 		 * the CSW anyway.  Since there's no point retrying the
1117 		 * the command, we'll return fake sense data indicating
1118 		 * Illegal Request, Invalid Field in CDB.
1119 		 */
1120 		if (result == USB_STOR_XFER_LONG)
1121 			fake_sense = 1;
1122 	}
1123 
1124 	/* See flow chart on pg 15 of the Bulk Only Transport spec for
1125 	 * an explanation of how this code works.
1126 	 */
1127 
1128 	/* get CSW for device status */
1129 	US_DEBUGP("Attempting to get CSW...\n");
1130 	result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1131 				bcs, US_BULK_CS_WRAP_LEN, &cswlen);
1132 
1133 	/* Some broken devices add unnecessary zero-length packets to the
1134 	 * end of their data transfers.  Such packets show up as 0-length
1135 	 * CSWs.  If we encounter such a thing, try to read the CSW again.
1136 	 */
1137 	if (result == USB_STOR_XFER_SHORT && cswlen == 0) {
1138 		US_DEBUGP("Received 0-length CSW; retrying...\n");
1139 		result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1140 				bcs, US_BULK_CS_WRAP_LEN, &cswlen);
1141 	}
1142 
1143 	/* did the attempt to read the CSW fail? */
1144 	if (result == USB_STOR_XFER_STALLED) {
1145 
1146 		/* get the status again */
1147 		US_DEBUGP("Attempting to get CSW (2nd try)...\n");
1148 		result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1149 				bcs, US_BULK_CS_WRAP_LEN, NULL);
1150 	}
1151 
1152 	/* if we still have a failure at this point, we're in trouble */
1153 	US_DEBUGP("Bulk status result = %d\n", result);
1154 	if (result != USB_STOR_XFER_GOOD)
1155 		return USB_STOR_TRANSPORT_ERROR;
1156 
1157 	/* check bulk status */
1158 	residue = le32_to_cpu(bcs->Residue);
1159 	US_DEBUGP("Bulk Status S 0x%x T 0x%x R %u Stat 0x%x\n",
1160 			le32_to_cpu(bcs->Signature), bcs->Tag,
1161 			residue, bcs->Status);
1162 	if (!(bcs->Tag == us->tag || (us->fflags & US_FL_BULK_IGNORE_TAG)) ||
1163 		bcs->Status > US_BULK_STAT_PHASE) {
1164 		US_DEBUGP("Bulk logical error\n");
1165 		return USB_STOR_TRANSPORT_ERROR;
1166 	}
1167 
1168 	/* Some broken devices report odd signatures, so we do not check them
1169 	 * for validity against the spec. We store the first one we see,
1170 	 * and check subsequent transfers for validity against this signature.
1171 	 */
1172 	if (!us->bcs_signature) {
1173 		us->bcs_signature = bcs->Signature;
1174 		if (us->bcs_signature != cpu_to_le32(US_BULK_CS_SIGN))
1175 			US_DEBUGP("Learnt BCS signature 0x%08X\n",
1176 					le32_to_cpu(us->bcs_signature));
1177 	} else if (bcs->Signature != us->bcs_signature) {
1178 		US_DEBUGP("Signature mismatch: got %08X, expecting %08X\n",
1179 			  le32_to_cpu(bcs->Signature),
1180 			  le32_to_cpu(us->bcs_signature));
1181 		return USB_STOR_TRANSPORT_ERROR;
1182 	}
1183 
1184 	/* try to compute the actual residue, based on how much data
1185 	 * was really transferred and what the device tells us */
1186 	if (residue && !(us->fflags & US_FL_IGNORE_RESIDUE)) {
1187 
1188 		/* Heuristically detect devices that generate bogus residues
1189 		 * by seeing what happens with INQUIRY and READ CAPACITY
1190 		 * commands.
1191 		 */
1192 		if (bcs->Status == US_BULK_STAT_OK &&
1193 				scsi_get_resid(srb) == 0 &&
1194 					((srb->cmnd[0] == INQUIRY &&
1195 						transfer_length == 36) ||
1196 					(srb->cmnd[0] == READ_CAPACITY &&
1197 						transfer_length == 8))) {
1198 			us->fflags |= US_FL_IGNORE_RESIDUE;
1199 
1200 		} else {
1201 			residue = min(residue, transfer_length);
1202 			scsi_set_resid(srb, max(scsi_get_resid(srb),
1203 			                                       (int) residue));
1204 		}
1205 	}
1206 
1207 	/* based on the status code, we report good or bad */
1208 	switch (bcs->Status) {
1209 		case US_BULK_STAT_OK:
1210 			/* device babbled -- return fake sense data */
1211 			if (fake_sense) {
1212 				memcpy(srb->sense_buffer,
1213 				       usb_stor_sense_invalidCDB,
1214 				       sizeof(usb_stor_sense_invalidCDB));
1215 				return USB_STOR_TRANSPORT_NO_SENSE;
1216 			}
1217 
1218 			/* command good -- note that data could be short */
1219 			return USB_STOR_TRANSPORT_GOOD;
1220 
1221 		case US_BULK_STAT_FAIL:
1222 			/* command failed */
1223 			return USB_STOR_TRANSPORT_FAILED;
1224 
1225 		case US_BULK_STAT_PHASE:
1226 			/* phase error -- note that a transport reset will be
1227 			 * invoked by the invoke_transport() function
1228 			 */
1229 			return USB_STOR_TRANSPORT_ERROR;
1230 	}
1231 
1232 	/* we should never get here, but if we do, we're in trouble */
1233 	return USB_STOR_TRANSPORT_ERROR;
1234 }
1235 EXPORT_SYMBOL_GPL(usb_stor_Bulk_transport);
1236 
1237 /***********************************************************************
1238  * Reset routines
1239  ***********************************************************************/
1240 
1241 /* This is the common part of the device reset code.
1242  *
1243  * It's handy that every transport mechanism uses the control endpoint for
1244  * resets.
1245  *
1246  * Basically, we send a reset with a 5-second timeout, so we don't get
1247  * jammed attempting to do the reset.
1248  */
1249 static int usb_stor_reset_common(struct us_data *us,
1250 		u8 request, u8 requesttype,
1251 		u16 value, u16 index, void *data, u16 size)
1252 {
1253 	int result;
1254 	int result2;
1255 
1256 	if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1257 		US_DEBUGP("No reset during disconnect\n");
1258 		return -EIO;
1259 	}
1260 
1261 	result = usb_stor_control_msg(us, us->send_ctrl_pipe,
1262 			request, requesttype, value, index, data, size,
1263 			5*HZ);
1264 	if (result < 0) {
1265 		US_DEBUGP("Soft reset failed: %d\n", result);
1266 		return result;
1267 	}
1268 
1269 	/* Give the device some time to recover from the reset,
1270 	 * but don't delay disconnect processing. */
1271 	wait_event_interruptible_timeout(us->delay_wait,
1272 			test_bit(US_FLIDX_DISCONNECTING, &us->dflags),
1273 			HZ*6);
1274 	if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1275 		US_DEBUGP("Reset interrupted by disconnect\n");
1276 		return -EIO;
1277 	}
1278 
1279 	US_DEBUGP("Soft reset: clearing bulk-in endpoint halt\n");
1280 	result = usb_stor_clear_halt(us, us->recv_bulk_pipe);
1281 
1282 	US_DEBUGP("Soft reset: clearing bulk-out endpoint halt\n");
1283 	result2 = usb_stor_clear_halt(us, us->send_bulk_pipe);
1284 
1285 	/* return a result code based on the result of the clear-halts */
1286 	if (result >= 0)
1287 		result = result2;
1288 	if (result < 0)
1289 		US_DEBUGP("Soft reset failed\n");
1290 	else
1291 		US_DEBUGP("Soft reset done\n");
1292 	return result;
1293 }
1294 
1295 /* This issues a CB[I] Reset to the device in question
1296  */
1297 #define CB_RESET_CMD_SIZE	12
1298 
1299 int usb_stor_CB_reset(struct us_data *us)
1300 {
1301 	US_DEBUGP("%s called\n", __func__);
1302 
1303 	memset(us->iobuf, 0xFF, CB_RESET_CMD_SIZE);
1304 	us->iobuf[0] = SEND_DIAGNOSTIC;
1305 	us->iobuf[1] = 4;
1306 	return usb_stor_reset_common(us, US_CBI_ADSC,
1307 				 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1308 				 0, us->ifnum, us->iobuf, CB_RESET_CMD_SIZE);
1309 }
1310 EXPORT_SYMBOL_GPL(usb_stor_CB_reset);
1311 
1312 /* This issues a Bulk-only Reset to the device in question, including
1313  * clearing the subsequent endpoint halts that may occur.
1314  */
1315 int usb_stor_Bulk_reset(struct us_data *us)
1316 {
1317 	US_DEBUGP("%s called\n", __func__);
1318 
1319 	return usb_stor_reset_common(us, US_BULK_RESET_REQUEST,
1320 				 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1321 				 0, us->ifnum, NULL, 0);
1322 }
1323 EXPORT_SYMBOL_GPL(usb_stor_Bulk_reset);
1324 
1325 /* Issue a USB port reset to the device.  The caller must not hold
1326  * us->dev_mutex.
1327  */
1328 int usb_stor_port_reset(struct us_data *us)
1329 {
1330 	int result;
1331 
1332 	/*for these devices we must use the class specific method */
1333 	if (us->pusb_dev->quirks & USB_QUIRK_RESET_MORPHS)
1334 		return -EPERM;
1335 
1336 	result = usb_lock_device_for_reset(us->pusb_dev, us->pusb_intf);
1337 	if (result < 0)
1338 		US_DEBUGP("unable to lock device for reset: %d\n", result);
1339 	else {
1340 		/* Were we disconnected while waiting for the lock? */
1341 		if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1342 			result = -EIO;
1343 			US_DEBUGP("No reset during disconnect\n");
1344 		} else {
1345 			result = usb_reset_device(us->pusb_dev);
1346 			US_DEBUGP("usb_reset_device returns %d\n",
1347 					result);
1348 		}
1349 		usb_unlock_device(us->pusb_dev);
1350 	}
1351 	return result;
1352 }
1353