xref: /openbmc/linux/drivers/usb/storage/transport.c (revision 6ee73861)
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/errno.h>
48 #include <linux/slab.h>
49 
50 #include <scsi/scsi.h>
51 #include <scsi/scsi_eh.h>
52 #include <scsi/scsi_device.h>
53 
54 #include "usb.h"
55 #include "transport.h"
56 #include "protocol.h"
57 #include "scsiglue.h"
58 #include "debug.h"
59 
60 #include <linux/blkdev.h>
61 #include "../../scsi/sd.h"
62 
63 
64 /***********************************************************************
65  * Data transfer routines
66  ***********************************************************************/
67 
68 /*
69  * This is subtle, so pay attention:
70  * ---------------------------------
71  * We're very concerned about races with a command abort.  Hanging this code
72  * is a sure fire way to hang the kernel.  (Note that this discussion applies
73  * only to transactions resulting from a scsi queued-command, since only
74  * these transactions are subject to a scsi abort.  Other transactions, such
75  * as those occurring during device-specific initialization, must be handled
76  * by a separate code path.)
77  *
78  * The abort function (usb_storage_command_abort() in scsiglue.c) first
79  * sets the machine state and the ABORTING bit in us->dflags to prevent
80  * new URBs from being submitted.  It then calls usb_stor_stop_transport()
81  * below, which atomically tests-and-clears the URB_ACTIVE bit in us->dflags
82  * to see if the current_urb needs to be stopped.  Likewise, the SG_ACTIVE
83  * bit is tested to see if the current_sg scatter-gather request needs to be
84  * stopped.  The timeout callback routine does much the same thing.
85  *
86  * When a disconnect occurs, the DISCONNECTING bit in us->dflags is set to
87  * prevent new URBs from being submitted, and usb_stor_stop_transport() is
88  * called to stop any ongoing requests.
89  *
90  * The submit function first verifies that the submitting is allowed
91  * (neither ABORTING nor DISCONNECTING bits are set) and that the submit
92  * completes without errors, and only then sets the URB_ACTIVE bit.  This
93  * prevents the stop_transport() function from trying to cancel the URB
94  * while the submit call is underway.  Next, the submit function must test
95  * the flags to see if an abort or disconnect occurred during the submission
96  * or before the URB_ACTIVE bit was set.  If so, it's essential to cancel
97  * the URB if it hasn't been cancelled already (i.e., if the URB_ACTIVE bit
98  * is still set).  Either way, the function must then wait for the URB to
99  * finish.  Note that the URB can still be in progress even after a call to
100  * usb_unlink_urb() returns.
101  *
102  * The idea is that (1) once the ABORTING or DISCONNECTING bit is set,
103  * either the stop_transport() function or the submitting function
104  * is guaranteed to call usb_unlink_urb() for an active URB,
105  * and (2) test_and_clear_bit() prevents usb_unlink_urb() from being
106  * called more than once or from being called during usb_submit_urb().
107  */
108 
109 /* This is the completion handler which will wake us up when an URB
110  * completes.
111  */
112 static void usb_stor_blocking_completion(struct urb *urb)
113 {
114 	struct completion *urb_done_ptr = urb->context;
115 
116 	complete(urb_done_ptr);
117 }
118 
119 /* This is the common part of the URB message submission code
120  *
121  * All URBs from the usb-storage driver involved in handling a queued scsi
122  * command _must_ pass through this function (or something like it) for the
123  * abort mechanisms to work properly.
124  */
125 static int usb_stor_msg_common(struct us_data *us, int timeout)
126 {
127 	struct completion urb_done;
128 	long timeleft;
129 	int status;
130 
131 	/* don't submit URBs during abort processing */
132 	if (test_bit(US_FLIDX_ABORTING, &us->dflags))
133 		return -EIO;
134 
135 	/* set up data structures for the wakeup system */
136 	init_completion(&urb_done);
137 
138 	/* fill the common fields in the URB */
139 	us->current_urb->context = &urb_done;
140 	us->current_urb->actual_length = 0;
141 	us->current_urb->error_count = 0;
142 	us->current_urb->status = 0;
143 
144 	/* we assume that if transfer_buffer isn't us->iobuf then it
145 	 * hasn't been mapped for DMA.  Yes, this is clunky, but it's
146 	 * easier than always having the caller tell us whether the
147 	 * transfer buffer has already been mapped. */
148 	us->current_urb->transfer_flags = URB_NO_SETUP_DMA_MAP;
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 	us->current_urb->setup_dma = us->cr_dma;
153 
154 	/* submit the URB */
155 	status = usb_submit_urb(us->current_urb, GFP_NOIO);
156 	if (status) {
157 		/* something went wrong */
158 		return status;
159 	}
160 
161 	/* since the URB has been submitted successfully, it's now okay
162 	 * to cancel it */
163 	set_bit(US_FLIDX_URB_ACTIVE, &us->dflags);
164 
165 	/* did an abort occur during the submission? */
166 	if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
167 
168 		/* cancel the URB, if it hasn't been cancelled already */
169 		if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
170 			US_DEBUGP("-- cancelling URB\n");
171 			usb_unlink_urb(us->current_urb);
172 		}
173 	}
174 
175 	/* wait for the completion of the URB */
176 	timeleft = wait_for_completion_interruptible_timeout(
177 			&urb_done, timeout ? : MAX_SCHEDULE_TIMEOUT);
178 
179 	clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags);
180 
181 	if (timeleft <= 0) {
182 		US_DEBUGP("%s -- cancelling URB\n",
183 			  timeleft == 0 ? "Timeout" : "Signal");
184 		usb_kill_urb(us->current_urb);
185 	}
186 
187 	/* return the URB status */
188 	return us->current_urb->status;
189 }
190 
191 /*
192  * Transfer one control message, with timeouts, and allowing early
193  * termination.  Return codes are usual -Exxx, *not* USB_STOR_XFER_xxx.
194  */
195 int usb_stor_control_msg(struct us_data *us, unsigned int pipe,
196 		 u8 request, u8 requesttype, u16 value, u16 index,
197 		 void *data, u16 size, int timeout)
198 {
199 	int status;
200 
201 	US_DEBUGP("%s: rq=%02x rqtype=%02x value=%04x index=%02x len=%u\n",
202 			__func__, request, requesttype,
203 			value, index, size);
204 
205 	/* fill in the devrequest structure */
206 	us->cr->bRequestType = requesttype;
207 	us->cr->bRequest = request;
208 	us->cr->wValue = cpu_to_le16(value);
209 	us->cr->wIndex = cpu_to_le16(index);
210 	us->cr->wLength = cpu_to_le16(size);
211 
212 	/* fill and submit the URB */
213 	usb_fill_control_urb(us->current_urb, us->pusb_dev, pipe,
214 			 (unsigned char*) us->cr, data, size,
215 			 usb_stor_blocking_completion, NULL);
216 	status = usb_stor_msg_common(us, timeout);
217 
218 	/* return the actual length of the data transferred if no error */
219 	if (status == 0)
220 		status = us->current_urb->actual_length;
221 	return status;
222 }
223 EXPORT_SYMBOL_GPL(usb_stor_control_msg);
224 
225 /* This is a version of usb_clear_halt() that allows early termination and
226  * doesn't read the status from the device -- this is because some devices
227  * crash their internal firmware when the status is requested after a halt.
228  *
229  * A definitive list of these 'bad' devices is too difficult to maintain or
230  * make complete enough to be useful.  This problem was first observed on the
231  * Hagiwara FlashGate DUAL unit.  However, bus traces reveal that neither
232  * MacOS nor Windows checks the status after clearing a halt.
233  *
234  * Since many vendors in this space limit their testing to interoperability
235  * with these two OSes, specification violations like this one are common.
236  */
237 int usb_stor_clear_halt(struct us_data *us, unsigned int pipe)
238 {
239 	int result;
240 	int endp = usb_pipeendpoint(pipe);
241 
242 	if (usb_pipein (pipe))
243 		endp |= USB_DIR_IN;
244 
245 	result = usb_stor_control_msg(us, us->send_ctrl_pipe,
246 		USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT,
247 		USB_ENDPOINT_HALT, endp,
248 		NULL, 0, 3*HZ);
249 
250 	if (result >= 0)
251 		usb_reset_endpoint(us->pusb_dev, endp);
252 
253 	US_DEBUGP("%s: result = %d\n", __func__, result);
254 	return result;
255 }
256 EXPORT_SYMBOL_GPL(usb_stor_clear_halt);
257 
258 
259 /*
260  * Interpret the results of a URB transfer
261  *
262  * This function prints appropriate debugging messages, clears halts on
263  * non-control endpoints, and translates the status to the corresponding
264  * USB_STOR_XFER_xxx return code.
265  */
266 static int interpret_urb_result(struct us_data *us, unsigned int pipe,
267 		unsigned int length, int result, unsigned int partial)
268 {
269 	US_DEBUGP("Status code %d; transferred %u/%u\n",
270 			result, partial, length);
271 	switch (result) {
272 
273 	/* no error code; did we send all the data? */
274 	case 0:
275 		if (partial != length) {
276 			US_DEBUGP("-- short transfer\n");
277 			return USB_STOR_XFER_SHORT;
278 		}
279 
280 		US_DEBUGP("-- transfer complete\n");
281 		return USB_STOR_XFER_GOOD;
282 
283 	/* stalled */
284 	case -EPIPE:
285 		/* for control endpoints, (used by CB[I]) a stall indicates
286 		 * a failed command */
287 		if (usb_pipecontrol(pipe)) {
288 			US_DEBUGP("-- stall on control pipe\n");
289 			return USB_STOR_XFER_STALLED;
290 		}
291 
292 		/* for other sorts of endpoint, clear the stall */
293 		US_DEBUGP("clearing endpoint halt for pipe 0x%x\n", pipe);
294 		if (usb_stor_clear_halt(us, pipe) < 0)
295 			return USB_STOR_XFER_ERROR;
296 		return USB_STOR_XFER_STALLED;
297 
298 	/* babble - the device tried to send more than we wanted to read */
299 	case -EOVERFLOW:
300 		US_DEBUGP("-- babble\n");
301 		return USB_STOR_XFER_LONG;
302 
303 	/* the transfer was cancelled by abort, disconnect, or timeout */
304 	case -ECONNRESET:
305 		US_DEBUGP("-- transfer cancelled\n");
306 		return USB_STOR_XFER_ERROR;
307 
308 	/* short scatter-gather read transfer */
309 	case -EREMOTEIO:
310 		US_DEBUGP("-- short read transfer\n");
311 		return USB_STOR_XFER_SHORT;
312 
313 	/* abort or disconnect in progress */
314 	case -EIO:
315 		US_DEBUGP("-- abort or disconnect in progress\n");
316 		return USB_STOR_XFER_ERROR;
317 
318 	/* the catch-all error case */
319 	default:
320 		US_DEBUGP("-- unknown error\n");
321 		return USB_STOR_XFER_ERROR;
322 	}
323 }
324 
325 /*
326  * Transfer one control message, without timeouts, but allowing early
327  * termination.  Return codes are USB_STOR_XFER_xxx.
328  */
329 int usb_stor_ctrl_transfer(struct us_data *us, unsigned int pipe,
330 		u8 request, u8 requesttype, u16 value, u16 index,
331 		void *data, u16 size)
332 {
333 	int result;
334 
335 	US_DEBUGP("%s: rq=%02x rqtype=%02x value=%04x index=%02x len=%u\n",
336 			__func__, request, requesttype,
337 			value, index, size);
338 
339 	/* fill in the devrequest structure */
340 	us->cr->bRequestType = requesttype;
341 	us->cr->bRequest = request;
342 	us->cr->wValue = cpu_to_le16(value);
343 	us->cr->wIndex = cpu_to_le16(index);
344 	us->cr->wLength = cpu_to_le16(size);
345 
346 	/* fill and submit the URB */
347 	usb_fill_control_urb(us->current_urb, us->pusb_dev, pipe,
348 			 (unsigned char*) us->cr, data, size,
349 			 usb_stor_blocking_completion, NULL);
350 	result = usb_stor_msg_common(us, 0);
351 
352 	return interpret_urb_result(us, pipe, size, result,
353 			us->current_urb->actual_length);
354 }
355 EXPORT_SYMBOL_GPL(usb_stor_ctrl_transfer);
356 
357 /*
358  * Receive one interrupt buffer, without timeouts, but allowing early
359  * termination.  Return codes are USB_STOR_XFER_xxx.
360  *
361  * This routine always uses us->recv_intr_pipe as the pipe and
362  * us->ep_bInterval as the interrupt interval.
363  */
364 static int usb_stor_intr_transfer(struct us_data *us, void *buf,
365 				  unsigned int length)
366 {
367 	int result;
368 	unsigned int pipe = us->recv_intr_pipe;
369 	unsigned int maxp;
370 
371 	US_DEBUGP("%s: xfer %u bytes\n", __func__, length);
372 
373 	/* calculate the max packet size */
374 	maxp = usb_maxpacket(us->pusb_dev, pipe, usb_pipeout(pipe));
375 	if (maxp > length)
376 		maxp = length;
377 
378 	/* fill and submit the URB */
379 	usb_fill_int_urb(us->current_urb, us->pusb_dev, pipe, buf,
380 			maxp, usb_stor_blocking_completion, NULL,
381 			us->ep_bInterval);
382 	result = usb_stor_msg_common(us, 0);
383 
384 	return interpret_urb_result(us, pipe, length, result,
385 			us->current_urb->actual_length);
386 }
387 
388 /*
389  * Transfer one buffer via bulk pipe, without timeouts, but allowing early
390  * termination.  Return codes are USB_STOR_XFER_xxx.  If the bulk pipe
391  * stalls during the transfer, the halt is automatically cleared.
392  */
393 int usb_stor_bulk_transfer_buf(struct us_data *us, unsigned int pipe,
394 	void *buf, unsigned int length, unsigned int *act_len)
395 {
396 	int result;
397 
398 	US_DEBUGP("%s: xfer %u bytes\n", __func__, length);
399 
400 	/* fill and submit the URB */
401 	usb_fill_bulk_urb(us->current_urb, us->pusb_dev, pipe, buf, length,
402 		      usb_stor_blocking_completion, NULL);
403 	result = usb_stor_msg_common(us, 0);
404 
405 	/* store the actual length of the data transferred */
406 	if (act_len)
407 		*act_len = us->current_urb->actual_length;
408 	return interpret_urb_result(us, pipe, length, result,
409 			us->current_urb->actual_length);
410 }
411 EXPORT_SYMBOL_GPL(usb_stor_bulk_transfer_buf);
412 
413 /*
414  * Transfer a scatter-gather list via bulk transfer
415  *
416  * This function does basically the same thing as usb_stor_bulk_transfer_buf()
417  * above, but it uses the usbcore scatter-gather library.
418  */
419 static int usb_stor_bulk_transfer_sglist(struct us_data *us, unsigned int pipe,
420 		struct scatterlist *sg, int num_sg, unsigned int length,
421 		unsigned int *act_len)
422 {
423 	int result;
424 
425 	/* don't submit s-g requests during abort processing */
426 	if (test_bit(US_FLIDX_ABORTING, &us->dflags))
427 		return USB_STOR_XFER_ERROR;
428 
429 	/* initialize the scatter-gather request block */
430 	US_DEBUGP("%s: xfer %u bytes, %d entries\n", __func__,
431 			length, num_sg);
432 	result = usb_sg_init(&us->current_sg, us->pusb_dev, pipe, 0,
433 			sg, num_sg, length, GFP_NOIO);
434 	if (result) {
435 		US_DEBUGP("usb_sg_init returned %d\n", result);
436 		return USB_STOR_XFER_ERROR;
437 	}
438 
439 	/* since the block has been initialized successfully, it's now
440 	 * okay to cancel it */
441 	set_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
442 
443 	/* did an abort occur during the submission? */
444 	if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
445 
446 		/* cancel the request, if it hasn't been cancelled already */
447 		if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
448 			US_DEBUGP("-- cancelling sg request\n");
449 			usb_sg_cancel(&us->current_sg);
450 		}
451 	}
452 
453 	/* wait for the completion of the transfer */
454 	usb_sg_wait(&us->current_sg);
455 	clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
456 
457 	result = us->current_sg.status;
458 	if (act_len)
459 		*act_len = us->current_sg.bytes;
460 	return interpret_urb_result(us, pipe, length, result,
461 			us->current_sg.bytes);
462 }
463 
464 /*
465  * Common used function. Transfer a complete command
466  * via usb_stor_bulk_transfer_sglist() above. Set cmnd resid
467  */
468 int usb_stor_bulk_srb(struct us_data* us, unsigned int pipe,
469 		      struct scsi_cmnd* srb)
470 {
471 	unsigned int partial;
472 	int result = usb_stor_bulk_transfer_sglist(us, pipe, scsi_sglist(srb),
473 				      scsi_sg_count(srb), scsi_bufflen(srb),
474 				      &partial);
475 
476 	scsi_set_resid(srb, scsi_bufflen(srb) - partial);
477 	return result;
478 }
479 EXPORT_SYMBOL_GPL(usb_stor_bulk_srb);
480 
481 /*
482  * Transfer an entire SCSI command's worth of data payload over the bulk
483  * pipe.
484  *
485  * Note that this uses usb_stor_bulk_transfer_buf() and
486  * usb_stor_bulk_transfer_sglist() to achieve its goals --
487  * this function simply determines whether we're going to use
488  * scatter-gather or not, and acts appropriately.
489  */
490 int usb_stor_bulk_transfer_sg(struct us_data* us, unsigned int pipe,
491 		void *buf, unsigned int length_left, int use_sg, int *residual)
492 {
493 	int result;
494 	unsigned int partial;
495 
496 	/* are we scatter-gathering? */
497 	if (use_sg) {
498 		/* use the usb core scatter-gather primitives */
499 		result = usb_stor_bulk_transfer_sglist(us, pipe,
500 				(struct scatterlist *) buf, use_sg,
501 				length_left, &partial);
502 		length_left -= partial;
503 	} else {
504 		/* no scatter-gather, just make the request */
505 		result = usb_stor_bulk_transfer_buf(us, pipe, buf,
506 				length_left, &partial);
507 		length_left -= partial;
508 	}
509 
510 	/* store the residual and return the error code */
511 	if (residual)
512 		*residual = length_left;
513 	return result;
514 }
515 EXPORT_SYMBOL_GPL(usb_stor_bulk_transfer_sg);
516 
517 /***********************************************************************
518  * Transport routines
519  ***********************************************************************/
520 
521 /* There are so many devices that report the capacity incorrectly,
522  * this routine was written to counteract some of the resulting
523  * problems.
524  */
525 static void last_sector_hacks(struct us_data *us, struct scsi_cmnd *srb)
526 {
527 	struct gendisk *disk;
528 	struct scsi_disk *sdkp;
529 	u32 sector;
530 
531 	/* To Report "Medium Error: Record Not Found */
532 	static unsigned char record_not_found[18] = {
533 		[0]	= 0x70,			/* current error */
534 		[2]	= MEDIUM_ERROR,		/* = 0x03 */
535 		[7]	= 0x0a,			/* additional length */
536 		[12]	= 0x14			/* Record Not Found */
537 	};
538 
539 	/* If last-sector problems can't occur, whether because the
540 	 * capacity was already decremented or because the device is
541 	 * known to report the correct capacity, then we don't need
542 	 * to do anything.
543 	 */
544 	if (!us->use_last_sector_hacks)
545 		return;
546 
547 	/* Was this command a READ(10) or a WRITE(10)? */
548 	if (srb->cmnd[0] != READ_10 && srb->cmnd[0] != WRITE_10)
549 		goto done;
550 
551 	/* Did this command access the last sector? */
552 	sector = (srb->cmnd[2] << 24) | (srb->cmnd[3] << 16) |
553 			(srb->cmnd[4] << 8) | (srb->cmnd[5]);
554 	disk = srb->request->rq_disk;
555 	if (!disk)
556 		goto done;
557 	sdkp = scsi_disk(disk);
558 	if (!sdkp)
559 		goto done;
560 	if (sector + 1 != sdkp->capacity)
561 		goto done;
562 
563 	if (srb->result == SAM_STAT_GOOD && scsi_get_resid(srb) == 0) {
564 
565 		/* The command succeeded.  We know this device doesn't
566 		 * have the last-sector bug, so stop checking it.
567 		 */
568 		us->use_last_sector_hacks = 0;
569 
570 	} else {
571 		/* The command failed.  Allow up to 3 retries in case this
572 		 * is some normal sort of failure.  After that, assume the
573 		 * capacity is wrong and we're trying to access the sector
574 		 * beyond the end.  Replace the result code and sense data
575 		 * with values that will cause the SCSI core to fail the
576 		 * command immediately, instead of going into an infinite
577 		 * (or even just a very long) retry loop.
578 		 */
579 		if (++us->last_sector_retries < 3)
580 			return;
581 		srb->result = SAM_STAT_CHECK_CONDITION;
582 		memcpy(srb->sense_buffer, record_not_found,
583 				sizeof(record_not_found));
584 	}
585 
586  done:
587 	/* Don't reset the retry counter for TEST UNIT READY commands,
588 	 * because they get issued after device resets which might be
589 	 * caused by a failed last-sector access.
590 	 */
591 	if (srb->cmnd[0] != TEST_UNIT_READY)
592 		us->last_sector_retries = 0;
593 }
594 
595 /* Invoke the transport and basic error-handling/recovery methods
596  *
597  * This is used by the protocol layers to actually send the message to
598  * the device and receive the response.
599  */
600 void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
601 {
602 	int need_auto_sense;
603 	int result;
604 
605 	/* send the command to the transport layer */
606 	scsi_set_resid(srb, 0);
607 	result = us->transport(srb, us);
608 
609 	/* if the command gets aborted by the higher layers, we need to
610 	 * short-circuit all other processing
611 	 */
612 	if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
613 		US_DEBUGP("-- command was aborted\n");
614 		srb->result = DID_ABORT << 16;
615 		goto Handle_Errors;
616 	}
617 
618 	/* if there is a transport error, reset and don't auto-sense */
619 	if (result == USB_STOR_TRANSPORT_ERROR) {
620 		US_DEBUGP("-- transport indicates error, resetting\n");
621 		srb->result = DID_ERROR << 16;
622 		goto Handle_Errors;
623 	}
624 
625 	/* if the transport provided its own sense data, don't auto-sense */
626 	if (result == USB_STOR_TRANSPORT_NO_SENSE) {
627 		srb->result = SAM_STAT_CHECK_CONDITION;
628 		last_sector_hacks(us, srb);
629 		return;
630 	}
631 
632 	srb->result = SAM_STAT_GOOD;
633 
634 	/* Determine if we need to auto-sense
635 	 *
636 	 * I normally don't use a flag like this, but it's almost impossible
637 	 * to understand what's going on here if I don't.
638 	 */
639 	need_auto_sense = 0;
640 
641 	/*
642 	 * If we're running the CB transport, which is incapable
643 	 * of determining status on its own, we will auto-sense
644 	 * unless the operation involved a data-in transfer.  Devices
645 	 * can signal most data-in errors by stalling the bulk-in pipe.
646 	 */
647 	if ((us->protocol == US_PR_CB || us->protocol == US_PR_DPCM_USB) &&
648 			srb->sc_data_direction != DMA_FROM_DEVICE) {
649 		US_DEBUGP("-- CB transport device requiring auto-sense\n");
650 		need_auto_sense = 1;
651 	}
652 
653 	/*
654 	 * If we have a failure, we're going to do a REQUEST_SENSE
655 	 * automatically.  Note that we differentiate between a command
656 	 * "failure" and an "error" in the transport mechanism.
657 	 */
658 	if (result == USB_STOR_TRANSPORT_FAILED) {
659 		US_DEBUGP("-- transport indicates command failure\n");
660 		need_auto_sense = 1;
661 	}
662 
663 	/*
664 	 * Determine if this device is SAT by seeing if the
665 	 * command executed successfully.  Otherwise we'll have
666 	 * to wait for at least one CHECK_CONDITION to determine
667 	 * SANE_SENSE support
668 	 */
669 	if ((srb->cmnd[0] == ATA_16 || srb->cmnd[0] == ATA_12) &&
670 	    result == USB_STOR_TRANSPORT_GOOD &&
671 	    !(us->fflags & US_FL_SANE_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 
696 		/* device supports and needs bigger sense buffer */
697 		if (us->fflags & US_FL_SANE_SENSE)
698 			sense_size = ~0;
699 Retry_Sense:
700 		US_DEBUGP("Issuing auto-REQUEST_SENSE\n");
701 
702 		scsi_eh_prep_cmnd(srb, &ses, NULL, 0, sense_size);
703 
704 		/* FIXME: we must do the protocol translation here */
705 		if (us->subclass == US_SC_RBC || us->subclass == US_SC_SCSI ||
706 				us->subclass == US_SC_CYP_ATACB)
707 			srb->cmd_len = 6;
708 		else
709 			srb->cmd_len = 12;
710 
711 		/* issue the auto-sense command */
712 		scsi_set_resid(srb, 0);
713 		temp_result = us->transport(us->srb, us);
714 
715 		/* let's clean up right away */
716 		scsi_eh_restore_cmnd(srb, &ses);
717 
718 		if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
719 			US_DEBUGP("-- auto-sense aborted\n");
720 			srb->result = DID_ABORT << 16;
721 			goto Handle_Errors;
722 		}
723 
724 		/* Some devices claim to support larger sense but fail when
725 		 * trying to request it. When a transport failure happens
726 		 * using US_FS_SANE_SENSE, we always retry with a standard
727 		 * (small) sense request. This fixes some USB GSM modems
728 		 */
729 		if (temp_result == USB_STOR_TRANSPORT_FAILED &&
730 		    (us->fflags & US_FL_SANE_SENSE) &&
731 		    sense_size != US_SENSE_SIZE) {
732 			US_DEBUGP("-- auto-sense failure, retry small sense\n");
733 			sense_size = US_SENSE_SIZE;
734 			goto Retry_Sense;
735 		}
736 
737 		/* Other failures */
738 		if (temp_result != USB_STOR_TRANSPORT_GOOD) {
739 			US_DEBUGP("-- auto-sense failure\n");
740 
741 			/* we skip the reset if this happens to be a
742 			 * multi-target device, since failure of an
743 			 * auto-sense is perfectly valid
744 			 */
745 			srb->result = DID_ERROR << 16;
746 			if (!(us->fflags & US_FL_SCM_MULT_TARG))
747 				goto Handle_Errors;
748 			return;
749 		}
750 
751 		/* If the sense data returned is larger than 18-bytes then we
752 		 * assume this device supports requesting more in the future.
753 		 * The response code must be 70h through 73h inclusive.
754 		 */
755 		if (srb->sense_buffer[7] > (US_SENSE_SIZE - 8) &&
756 		    !(us->fflags & US_FL_SANE_SENSE) &&
757 		    (srb->sense_buffer[0] & 0x7C) == 0x70) {
758 			US_DEBUGP("-- SANE_SENSE support enabled\n");
759 			us->fflags |= US_FL_SANE_SENSE;
760 
761 			/* Indicate to the user that we truncated their sense
762 			 * because we didn't know it supported larger sense.
763 			 */
764 			US_DEBUGP("-- Sense data truncated to %i from %i\n",
765 			          US_SENSE_SIZE,
766 			          srb->sense_buffer[7] + 8);
767 			srb->sense_buffer[7] = (US_SENSE_SIZE - 8);
768 		}
769 
770 		US_DEBUGP("-- Result from auto-sense is %d\n", temp_result);
771 		US_DEBUGP("-- code: 0x%x, key: 0x%x, ASC: 0x%x, ASCQ: 0x%x\n",
772 			  srb->sense_buffer[0],
773 			  srb->sense_buffer[2] & 0xf,
774 			  srb->sense_buffer[12],
775 			  srb->sense_buffer[13]);
776 #ifdef CONFIG_USB_STORAGE_DEBUG
777 		usb_stor_show_sense(
778 			  srb->sense_buffer[2] & 0xf,
779 			  srb->sense_buffer[12],
780 			  srb->sense_buffer[13]);
781 #endif
782 
783 		/* set the result so the higher layers expect this data */
784 		srb->result = SAM_STAT_CHECK_CONDITION;
785 
786 		/* We often get empty sense data.  This could indicate that
787 		 * everything worked or that there was an unspecified
788 		 * problem.  We have to decide which.
789 		 */
790 		if (	/* Filemark 0, ignore EOM, ILI 0, no sense */
791 				(srb->sense_buffer[2] & 0xaf) == 0 &&
792 			/* No ASC or ASCQ */
793 				srb->sense_buffer[12] == 0 &&
794 				srb->sense_buffer[13] == 0) {
795 
796 			/* If things are really okay, then let's show that.
797 			 * Zero out the sense buffer so the higher layers
798 			 * won't realize we did an unsolicited auto-sense.
799 			 */
800 			if (result == USB_STOR_TRANSPORT_GOOD) {
801 				srb->result = SAM_STAT_GOOD;
802 				srb->sense_buffer[0] = 0x0;
803 
804 			/* If there was a problem, report an unspecified
805 			 * hardware error to prevent the higher layers from
806 			 * entering an infinite retry loop.
807 			 */
808 			} else {
809 				srb->result = DID_ERROR << 16;
810 				srb->sense_buffer[2] = HARDWARE_ERROR;
811 			}
812 		}
813 	}
814 
815 	/* Did we transfer less than the minimum amount required? */
816 	if ((srb->result == SAM_STAT_GOOD || srb->sense_buffer[2] == 0) &&
817 			scsi_bufflen(srb) - scsi_get_resid(srb) < srb->underflow)
818 		srb->result = DID_ERROR << 16;
819 
820 	last_sector_hacks(us, srb);
821 	return;
822 
823 	/* Error and abort processing: try to resynchronize with the device
824 	 * by issuing a port reset.  If that fails, try a class-specific
825 	 * device reset. */
826   Handle_Errors:
827 
828 	/* Set the RESETTING bit, and clear the ABORTING bit so that
829 	 * the reset may proceed. */
830 	scsi_lock(us_to_host(us));
831 	set_bit(US_FLIDX_RESETTING, &us->dflags);
832 	clear_bit(US_FLIDX_ABORTING, &us->dflags);
833 	scsi_unlock(us_to_host(us));
834 
835 	/* We must release the device lock because the pre_reset routine
836 	 * will want to acquire it. */
837 	mutex_unlock(&us->dev_mutex);
838 	result = usb_stor_port_reset(us);
839 	mutex_lock(&us->dev_mutex);
840 
841 	if (result < 0) {
842 		scsi_lock(us_to_host(us));
843 		usb_stor_report_device_reset(us);
844 		scsi_unlock(us_to_host(us));
845 		us->transport_reset(us);
846 	}
847 	clear_bit(US_FLIDX_RESETTING, &us->dflags);
848 	last_sector_hacks(us, srb);
849 }
850 
851 /* Stop the current URB transfer */
852 void usb_stor_stop_transport(struct us_data *us)
853 {
854 	US_DEBUGP("%s called\n", __func__);
855 
856 	/* If the state machine is blocked waiting for an URB,
857 	 * let's wake it up.  The test_and_clear_bit() call
858 	 * guarantees that if a URB has just been submitted,
859 	 * it won't be cancelled more than once. */
860 	if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
861 		US_DEBUGP("-- cancelling URB\n");
862 		usb_unlink_urb(us->current_urb);
863 	}
864 
865 	/* If we are waiting for a scatter-gather operation, cancel it. */
866 	if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
867 		US_DEBUGP("-- cancelling sg request\n");
868 		usb_sg_cancel(&us->current_sg);
869 	}
870 }
871 
872 /*
873  * Control/Bulk and Control/Bulk/Interrupt transport
874  */
875 
876 int usb_stor_CB_transport(struct scsi_cmnd *srb, struct us_data *us)
877 {
878 	unsigned int transfer_length = scsi_bufflen(srb);
879 	unsigned int pipe = 0;
880 	int result;
881 
882 	/* COMMAND STAGE */
883 	/* let's send the command via the control pipe */
884 	result = usb_stor_ctrl_transfer(us, us->send_ctrl_pipe,
885 				      US_CBI_ADSC,
886 				      USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0,
887 				      us->ifnum, srb->cmnd, srb->cmd_len);
888 
889 	/* check the return code for the command */
890 	US_DEBUGP("Call to usb_stor_ctrl_transfer() returned %d\n", result);
891 
892 	/* if we stalled the command, it means command failed */
893 	if (result == USB_STOR_XFER_STALLED) {
894 		return USB_STOR_TRANSPORT_FAILED;
895 	}
896 
897 	/* Uh oh... serious problem here */
898 	if (result != USB_STOR_XFER_GOOD) {
899 		return USB_STOR_TRANSPORT_ERROR;
900 	}
901 
902 	/* DATA STAGE */
903 	/* transfer the data payload for this command, if one exists*/
904 	if (transfer_length) {
905 		pipe = srb->sc_data_direction == DMA_FROM_DEVICE ?
906 				us->recv_bulk_pipe : us->send_bulk_pipe;
907 		result = usb_stor_bulk_srb(us, pipe, srb);
908 		US_DEBUGP("CBI data stage result is 0x%x\n", result);
909 
910 		/* if we stalled the data transfer it means command failed */
911 		if (result == USB_STOR_XFER_STALLED)
912 			return USB_STOR_TRANSPORT_FAILED;
913 		if (result > USB_STOR_XFER_STALLED)
914 			return USB_STOR_TRANSPORT_ERROR;
915 	}
916 
917 	/* STATUS STAGE */
918 
919 	/* NOTE: CB does not have a status stage.  Silly, I know.  So
920 	 * we have to catch this at a higher level.
921 	 */
922 	if (us->protocol != US_PR_CBI)
923 		return USB_STOR_TRANSPORT_GOOD;
924 
925 	result = usb_stor_intr_transfer(us, us->iobuf, 2);
926 	US_DEBUGP("Got interrupt data (0x%x, 0x%x)\n",
927 			us->iobuf[0], us->iobuf[1]);
928 	if (result != USB_STOR_XFER_GOOD)
929 		return USB_STOR_TRANSPORT_ERROR;
930 
931 	/* UFI gives us ASC and ASCQ, like a request sense
932 	 *
933 	 * REQUEST_SENSE and INQUIRY don't affect the sense data on UFI
934 	 * devices, so we ignore the information for those commands.  Note
935 	 * that this means we could be ignoring a real error on these
936 	 * commands, but that can't be helped.
937 	 */
938 	if (us->subclass == US_SC_UFI) {
939 		if (srb->cmnd[0] == REQUEST_SENSE ||
940 		    srb->cmnd[0] == INQUIRY)
941 			return USB_STOR_TRANSPORT_GOOD;
942 		if (us->iobuf[0])
943 			goto Failed;
944 		return USB_STOR_TRANSPORT_GOOD;
945 	}
946 
947 	/* If not UFI, we interpret the data as a result code
948 	 * The first byte should always be a 0x0.
949 	 *
950 	 * Some bogus devices don't follow that rule.  They stuff the ASC
951 	 * into the first byte -- so if it's non-zero, call it a failure.
952 	 */
953 	if (us->iobuf[0]) {
954 		US_DEBUGP("CBI IRQ data showed reserved bType 0x%x\n",
955 				us->iobuf[0]);
956 		goto Failed;
957 
958 	}
959 
960 	/* The second byte & 0x0F should be 0x0 for good, otherwise error */
961 	switch (us->iobuf[1] & 0x0F) {
962 		case 0x00:
963 			return USB_STOR_TRANSPORT_GOOD;
964 		case 0x01:
965 			goto Failed;
966 	}
967 	return USB_STOR_TRANSPORT_ERROR;
968 
969 	/* the CBI spec requires that the bulk pipe must be cleared
970 	 * following any data-in/out command failure (section 2.4.3.1.3)
971 	 */
972   Failed:
973 	if (pipe)
974 		usb_stor_clear_halt(us, pipe);
975 	return USB_STOR_TRANSPORT_FAILED;
976 }
977 EXPORT_SYMBOL_GPL(usb_stor_CB_transport);
978 
979 /*
980  * Bulk only transport
981  */
982 
983 /* Determine what the maximum LUN supported is */
984 int usb_stor_Bulk_max_lun(struct us_data *us)
985 {
986 	int result;
987 
988 	/* issue the command */
989 	us->iobuf[0] = 0;
990 	result = usb_stor_control_msg(us, us->recv_ctrl_pipe,
991 				 US_BULK_GET_MAX_LUN,
992 				 USB_DIR_IN | USB_TYPE_CLASS |
993 				 USB_RECIP_INTERFACE,
994 				 0, us->ifnum, us->iobuf, 1, 10*HZ);
995 
996 	US_DEBUGP("GetMaxLUN command result is %d, data is %d\n",
997 		  result, us->iobuf[0]);
998 
999 	/* if we have a successful request, return the result */
1000 	if (result > 0)
1001 		return us->iobuf[0];
1002 
1003 	/*
1004 	 * Some devices don't like GetMaxLUN.  They may STALL the control
1005 	 * pipe, they may return a zero-length result, they may do nothing at
1006 	 * all and timeout, or they may fail in even more bizarrely creative
1007 	 * ways.  In these cases the best approach is to use the default
1008 	 * value: only one LUN.
1009 	 */
1010 	return 0;
1011 }
1012 
1013 int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us)
1014 {
1015 	struct bulk_cb_wrap *bcb = (struct bulk_cb_wrap *) us->iobuf;
1016 	struct bulk_cs_wrap *bcs = (struct bulk_cs_wrap *) us->iobuf;
1017 	unsigned int transfer_length = scsi_bufflen(srb);
1018 	unsigned int residue;
1019 	int result;
1020 	int fake_sense = 0;
1021 	unsigned int cswlen;
1022 	unsigned int cbwlen = US_BULK_CB_WRAP_LEN;
1023 
1024 	/* Take care of BULK32 devices; set extra byte to 0 */
1025 	if (unlikely(us->fflags & US_FL_BULK32)) {
1026 		cbwlen = 32;
1027 		us->iobuf[31] = 0;
1028 	}
1029 
1030 	/* set up the command wrapper */
1031 	bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
1032 	bcb->DataTransferLength = cpu_to_le32(transfer_length);
1033 	bcb->Flags = srb->sc_data_direction == DMA_FROM_DEVICE ? 1 << 7 : 0;
1034 	bcb->Tag = ++us->tag;
1035 	bcb->Lun = srb->device->lun;
1036 	if (us->fflags & US_FL_SCM_MULT_TARG)
1037 		bcb->Lun |= srb->device->id << 4;
1038 	bcb->Length = srb->cmd_len;
1039 
1040 	/* copy the command payload */
1041 	memset(bcb->CDB, 0, sizeof(bcb->CDB));
1042 	memcpy(bcb->CDB, srb->cmnd, bcb->Length);
1043 
1044 	/* send it to out endpoint */
1045 	US_DEBUGP("Bulk Command S 0x%x T 0x%x L %d F %d Trg %d LUN %d CL %d\n",
1046 			le32_to_cpu(bcb->Signature), bcb->Tag,
1047 			le32_to_cpu(bcb->DataTransferLength), bcb->Flags,
1048 			(bcb->Lun >> 4), (bcb->Lun & 0x0F),
1049 			bcb->Length);
1050 	result = usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
1051 				bcb, cbwlen, NULL);
1052 	US_DEBUGP("Bulk command transfer result=%d\n", result);
1053 	if (result != USB_STOR_XFER_GOOD)
1054 		return USB_STOR_TRANSPORT_ERROR;
1055 
1056 	/* DATA STAGE */
1057 	/* send/receive data payload, if there is any */
1058 
1059 	/* Some USB-IDE converter chips need a 100us delay between the
1060 	 * command phase and the data phase.  Some devices need a little
1061 	 * more than that, probably because of clock rate inaccuracies. */
1062 	if (unlikely(us->fflags & US_FL_GO_SLOW))
1063 		udelay(125);
1064 
1065 	if (transfer_length) {
1066 		unsigned int pipe = srb->sc_data_direction == DMA_FROM_DEVICE ?
1067 				us->recv_bulk_pipe : us->send_bulk_pipe;
1068 		result = usb_stor_bulk_srb(us, pipe, srb);
1069 		US_DEBUGP("Bulk data transfer result 0x%x\n", result);
1070 		if (result == USB_STOR_XFER_ERROR)
1071 			return USB_STOR_TRANSPORT_ERROR;
1072 
1073 		/* If the device tried to send back more data than the
1074 		 * amount requested, the spec requires us to transfer
1075 		 * the CSW anyway.  Since there's no point retrying the
1076 		 * the command, we'll return fake sense data indicating
1077 		 * Illegal Request, Invalid Field in CDB.
1078 		 */
1079 		if (result == USB_STOR_XFER_LONG)
1080 			fake_sense = 1;
1081 	}
1082 
1083 	/* See flow chart on pg 15 of the Bulk Only Transport spec for
1084 	 * an explanation of how this code works.
1085 	 */
1086 
1087 	/* get CSW for device status */
1088 	US_DEBUGP("Attempting to get CSW...\n");
1089 	result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1090 				bcs, US_BULK_CS_WRAP_LEN, &cswlen);
1091 
1092 	/* Some broken devices add unnecessary zero-length packets to the
1093 	 * end of their data transfers.  Such packets show up as 0-length
1094 	 * CSWs.  If we encounter such a thing, try to read the CSW again.
1095 	 */
1096 	if (result == USB_STOR_XFER_SHORT && cswlen == 0) {
1097 		US_DEBUGP("Received 0-length CSW; retrying...\n");
1098 		result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1099 				bcs, US_BULK_CS_WRAP_LEN, &cswlen);
1100 	}
1101 
1102 	/* did the attempt to read the CSW fail? */
1103 	if (result == USB_STOR_XFER_STALLED) {
1104 
1105 		/* get the status again */
1106 		US_DEBUGP("Attempting to get CSW (2nd try)...\n");
1107 		result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1108 				bcs, US_BULK_CS_WRAP_LEN, NULL);
1109 	}
1110 
1111 	/* if we still have a failure at this point, we're in trouble */
1112 	US_DEBUGP("Bulk status result = %d\n", result);
1113 	if (result != USB_STOR_XFER_GOOD)
1114 		return USB_STOR_TRANSPORT_ERROR;
1115 
1116 	/* check bulk status */
1117 	residue = le32_to_cpu(bcs->Residue);
1118 	US_DEBUGP("Bulk Status S 0x%x T 0x%x R %u Stat 0x%x\n",
1119 			le32_to_cpu(bcs->Signature), bcs->Tag,
1120 			residue, bcs->Status);
1121 	if (!(bcs->Tag == us->tag || (us->fflags & US_FL_BULK_IGNORE_TAG)) ||
1122 		bcs->Status > US_BULK_STAT_PHASE) {
1123 		US_DEBUGP("Bulk logical error\n");
1124 		return USB_STOR_TRANSPORT_ERROR;
1125 	}
1126 
1127 	/* Some broken devices report odd signatures, so we do not check them
1128 	 * for validity against the spec. We store the first one we see,
1129 	 * and check subsequent transfers for validity against this signature.
1130 	 */
1131 	if (!us->bcs_signature) {
1132 		us->bcs_signature = bcs->Signature;
1133 		if (us->bcs_signature != cpu_to_le32(US_BULK_CS_SIGN))
1134 			US_DEBUGP("Learnt BCS signature 0x%08X\n",
1135 					le32_to_cpu(us->bcs_signature));
1136 	} else if (bcs->Signature != us->bcs_signature) {
1137 		US_DEBUGP("Signature mismatch: got %08X, expecting %08X\n",
1138 			  le32_to_cpu(bcs->Signature),
1139 			  le32_to_cpu(us->bcs_signature));
1140 		return USB_STOR_TRANSPORT_ERROR;
1141 	}
1142 
1143 	/* try to compute the actual residue, based on how much data
1144 	 * was really transferred and what the device tells us */
1145 	if (residue && !(us->fflags & US_FL_IGNORE_RESIDUE)) {
1146 
1147 		/* Heuristically detect devices that generate bogus residues
1148 		 * by seeing what happens with INQUIRY and READ CAPACITY
1149 		 * commands.
1150 		 */
1151 		if (bcs->Status == US_BULK_STAT_OK &&
1152 				scsi_get_resid(srb) == 0 &&
1153 					((srb->cmnd[0] == INQUIRY &&
1154 						transfer_length == 36) ||
1155 					(srb->cmnd[0] == READ_CAPACITY &&
1156 						transfer_length == 8))) {
1157 			us->fflags |= US_FL_IGNORE_RESIDUE;
1158 
1159 		} else {
1160 			residue = min(residue, transfer_length);
1161 			scsi_set_resid(srb, max(scsi_get_resid(srb),
1162 			                                       (int) residue));
1163 		}
1164 	}
1165 
1166 	/* based on the status code, we report good or bad */
1167 	switch (bcs->Status) {
1168 		case US_BULK_STAT_OK:
1169 			/* device babbled -- return fake sense data */
1170 			if (fake_sense) {
1171 				memcpy(srb->sense_buffer,
1172 				       usb_stor_sense_invalidCDB,
1173 				       sizeof(usb_stor_sense_invalidCDB));
1174 				return USB_STOR_TRANSPORT_NO_SENSE;
1175 			}
1176 
1177 			/* command good -- note that data could be short */
1178 			return USB_STOR_TRANSPORT_GOOD;
1179 
1180 		case US_BULK_STAT_FAIL:
1181 			/* command failed */
1182 			return USB_STOR_TRANSPORT_FAILED;
1183 
1184 		case US_BULK_STAT_PHASE:
1185 			/* phase error -- note that a transport reset will be
1186 			 * invoked by the invoke_transport() function
1187 			 */
1188 			return USB_STOR_TRANSPORT_ERROR;
1189 	}
1190 
1191 	/* we should never get here, but if we do, we're in trouble */
1192 	return USB_STOR_TRANSPORT_ERROR;
1193 }
1194 EXPORT_SYMBOL_GPL(usb_stor_Bulk_transport);
1195 
1196 /***********************************************************************
1197  * Reset routines
1198  ***********************************************************************/
1199 
1200 /* This is the common part of the device reset code.
1201  *
1202  * It's handy that every transport mechanism uses the control endpoint for
1203  * resets.
1204  *
1205  * Basically, we send a reset with a 5-second timeout, so we don't get
1206  * jammed attempting to do the reset.
1207  */
1208 static int usb_stor_reset_common(struct us_data *us,
1209 		u8 request, u8 requesttype,
1210 		u16 value, u16 index, void *data, u16 size)
1211 {
1212 	int result;
1213 	int result2;
1214 
1215 	if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1216 		US_DEBUGP("No reset during disconnect\n");
1217 		return -EIO;
1218 	}
1219 
1220 	result = usb_stor_control_msg(us, us->send_ctrl_pipe,
1221 			request, requesttype, value, index, data, size,
1222 			5*HZ);
1223 	if (result < 0) {
1224 		US_DEBUGP("Soft reset failed: %d\n", result);
1225 		return result;
1226 	}
1227 
1228 	/* Give the device some time to recover from the reset,
1229 	 * but don't delay disconnect processing. */
1230 	wait_event_interruptible_timeout(us->delay_wait,
1231 			test_bit(US_FLIDX_DISCONNECTING, &us->dflags),
1232 			HZ*6);
1233 	if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1234 		US_DEBUGP("Reset interrupted by disconnect\n");
1235 		return -EIO;
1236 	}
1237 
1238 	US_DEBUGP("Soft reset: clearing bulk-in endpoint halt\n");
1239 	result = usb_stor_clear_halt(us, us->recv_bulk_pipe);
1240 
1241 	US_DEBUGP("Soft reset: clearing bulk-out endpoint halt\n");
1242 	result2 = usb_stor_clear_halt(us, us->send_bulk_pipe);
1243 
1244 	/* return a result code based on the result of the clear-halts */
1245 	if (result >= 0)
1246 		result = result2;
1247 	if (result < 0)
1248 		US_DEBUGP("Soft reset failed\n");
1249 	else
1250 		US_DEBUGP("Soft reset done\n");
1251 	return result;
1252 }
1253 
1254 /* This issues a CB[I] Reset to the device in question
1255  */
1256 #define CB_RESET_CMD_SIZE	12
1257 
1258 int usb_stor_CB_reset(struct us_data *us)
1259 {
1260 	US_DEBUGP("%s called\n", __func__);
1261 
1262 	memset(us->iobuf, 0xFF, CB_RESET_CMD_SIZE);
1263 	us->iobuf[0] = SEND_DIAGNOSTIC;
1264 	us->iobuf[1] = 4;
1265 	return usb_stor_reset_common(us, US_CBI_ADSC,
1266 				 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1267 				 0, us->ifnum, us->iobuf, CB_RESET_CMD_SIZE);
1268 }
1269 EXPORT_SYMBOL_GPL(usb_stor_CB_reset);
1270 
1271 /* This issues a Bulk-only Reset to the device in question, including
1272  * clearing the subsequent endpoint halts that may occur.
1273  */
1274 int usb_stor_Bulk_reset(struct us_data *us)
1275 {
1276 	US_DEBUGP("%s called\n", __func__);
1277 
1278 	return usb_stor_reset_common(us, US_BULK_RESET_REQUEST,
1279 				 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1280 				 0, us->ifnum, NULL, 0);
1281 }
1282 EXPORT_SYMBOL_GPL(usb_stor_Bulk_reset);
1283 
1284 /* Issue a USB port reset to the device.  The caller must not hold
1285  * us->dev_mutex.
1286  */
1287 int usb_stor_port_reset(struct us_data *us)
1288 {
1289 	int result;
1290 
1291 	result = usb_lock_device_for_reset(us->pusb_dev, us->pusb_intf);
1292 	if (result < 0)
1293 		US_DEBUGP("unable to lock device for reset: %d\n", result);
1294 	else {
1295 		/* Were we disconnected while waiting for the lock? */
1296 		if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1297 			result = -EIO;
1298 			US_DEBUGP("No reset during disconnect\n");
1299 		} else {
1300 			result = usb_reset_device(us->pusb_dev);
1301 			US_DEBUGP("usb_reset_device returns %d\n",
1302 					result);
1303 		}
1304 		usb_unlock_device(us->pusb_dev);
1305 	}
1306 	return result;
1307 }
1308