xref: /openbmc/linux/drivers/usb/storage/transport.c (revision 4800cd83)
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 
50 #include <linux/usb/quirks.h>
51 
52 #include <scsi/scsi.h>
53 #include <scsi/scsi_eh.h>
54 #include <scsi/scsi_device.h>
55 
56 #include "usb.h"
57 #include "transport.h"
58 #include "protocol.h"
59 #include "scsiglue.h"
60 #include "debug.h"
61 
62 #include <linux/blkdev.h>
63 #include "../../scsi/sd.h"
64 
65 
66 /***********************************************************************
67  * Data transfer routines
68  ***********************************************************************/
69 
70 /*
71  * This is subtle, so pay attention:
72  * ---------------------------------
73  * We're very concerned about races with a command abort.  Hanging this code
74  * is a sure fire way to hang the kernel.  (Note that this discussion applies
75  * only to transactions resulting from a scsi queued-command, since only
76  * these transactions are subject to a scsi abort.  Other transactions, such
77  * as those occurring during device-specific initialization, must be handled
78  * by a separate code path.)
79  *
80  * The abort function (usb_storage_command_abort() in scsiglue.c) first
81  * sets the machine state and the ABORTING bit in us->dflags to prevent
82  * new URBs from being submitted.  It then calls usb_stor_stop_transport()
83  * below, which atomically tests-and-clears the URB_ACTIVE bit in us->dflags
84  * to see if the current_urb needs to be stopped.  Likewise, the SG_ACTIVE
85  * bit is tested to see if the current_sg scatter-gather request needs to be
86  * stopped.  The timeout callback routine does much the same thing.
87  *
88  * When a disconnect occurs, the DISCONNECTING bit in us->dflags is set to
89  * prevent new URBs from being submitted, and usb_stor_stop_transport() is
90  * called to stop any ongoing requests.
91  *
92  * The submit function first verifies that the submitting is allowed
93  * (neither ABORTING nor DISCONNECTING bits are set) and that the submit
94  * completes without errors, and only then sets the URB_ACTIVE bit.  This
95  * prevents the stop_transport() function from trying to cancel the URB
96  * while the submit call is underway.  Next, the submit function must test
97  * the flags to see if an abort or disconnect occurred during the submission
98  * or before the URB_ACTIVE bit was set.  If so, it's essential to cancel
99  * the URB if it hasn't been cancelled already (i.e., if the URB_ACTIVE bit
100  * is still set).  Either way, the function must then wait for the URB to
101  * finish.  Note that the URB can still be in progress even after a call to
102  * usb_unlink_urb() returns.
103  *
104  * The idea is that (1) once the ABORTING or DISCONNECTING bit is set,
105  * either the stop_transport() function or the submitting function
106  * is guaranteed to call usb_unlink_urb() for an active URB,
107  * and (2) test_and_clear_bit() prevents usb_unlink_urb() from being
108  * called more than once or from being called during usb_submit_urb().
109  */
110 
111 /* This is the completion handler which will wake us up when an URB
112  * completes.
113  */
114 static void usb_stor_blocking_completion(struct urb *urb)
115 {
116 	struct completion *urb_done_ptr = urb->context;
117 
118 	complete(urb_done_ptr);
119 }
120 
121 /* This is the common part of the URB message submission code
122  *
123  * All URBs from the usb-storage driver involved in handling a queued scsi
124  * command _must_ pass through this function (or something like it) for the
125  * abort mechanisms to work properly.
126  */
127 static int usb_stor_msg_common(struct us_data *us, int timeout)
128 {
129 	struct completion urb_done;
130 	long timeleft;
131 	int status;
132 
133 	/* don't submit URBs during abort processing */
134 	if (test_bit(US_FLIDX_ABORTING, &us->dflags))
135 		return -EIO;
136 
137 	/* set up data structures for the wakeup system */
138 	init_completion(&urb_done);
139 
140 	/* fill the common fields in the URB */
141 	us->current_urb->context = &urb_done;
142 	us->current_urb->transfer_flags = 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 	if (us->current_urb->transfer_buffer == us->iobuf)
149 		us->current_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
150 	us->current_urb->transfer_dma = us->iobuf_dma;
151 
152 	/* submit the URB */
153 	status = usb_submit_urb(us->current_urb, GFP_NOIO);
154 	if (status) {
155 		/* something went wrong */
156 		return status;
157 	}
158 
159 	/* since the URB has been submitted successfully, it's now okay
160 	 * to cancel it */
161 	set_bit(US_FLIDX_URB_ACTIVE, &us->dflags);
162 
163 	/* did an abort occur during the submission? */
164 	if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
165 
166 		/* cancel the URB, if it hasn't been cancelled already */
167 		if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
168 			US_DEBUGP("-- cancelling URB\n");
169 			usb_unlink_urb(us->current_urb);
170 		}
171 	}
172 
173 	/* wait for the completion of the URB */
174 	timeleft = wait_for_completion_interruptible_timeout(
175 			&urb_done, timeout ? : MAX_SCHEDULE_TIMEOUT);
176 
177 	clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags);
178 
179 	if (timeleft <= 0) {
180 		US_DEBUGP("%s -- cancelling URB\n",
181 			  timeleft == 0 ? "Timeout" : "Signal");
182 		usb_kill_urb(us->current_urb);
183 	}
184 
185 	/* return the URB status */
186 	return us->current_urb->status;
187 }
188 
189 /*
190  * Transfer one control message, with timeouts, and allowing early
191  * termination.  Return codes are usual -Exxx, *not* USB_STOR_XFER_xxx.
192  */
193 int usb_stor_control_msg(struct us_data *us, unsigned int pipe,
194 		 u8 request, u8 requesttype, u16 value, u16 index,
195 		 void *data, u16 size, int timeout)
196 {
197 	int status;
198 
199 	US_DEBUGP("%s: rq=%02x rqtype=%02x value=%04x index=%02x len=%u\n",
200 			__func__, request, requesttype,
201 			value, index, size);
202 
203 	/* fill in the devrequest structure */
204 	us->cr->bRequestType = requesttype;
205 	us->cr->bRequest = request;
206 	us->cr->wValue = cpu_to_le16(value);
207 	us->cr->wIndex = cpu_to_le16(index);
208 	us->cr->wLength = cpu_to_le16(size);
209 
210 	/* fill and submit the URB */
211 	usb_fill_control_urb(us->current_urb, us->pusb_dev, pipe,
212 			 (unsigned char*) us->cr, data, size,
213 			 usb_stor_blocking_completion, NULL);
214 	status = usb_stor_msg_common(us, timeout);
215 
216 	/* return the actual length of the data transferred if no error */
217 	if (status == 0)
218 		status = us->current_urb->actual_length;
219 	return status;
220 }
221 EXPORT_SYMBOL_GPL(usb_stor_control_msg);
222 
223 /* This is a version of usb_clear_halt() that allows early termination and
224  * doesn't read the status from the device -- this is because some devices
225  * crash their internal firmware when the status is requested after a halt.
226  *
227  * A definitive list of these 'bad' devices is too difficult to maintain or
228  * make complete enough to be useful.  This problem was first observed on the
229  * Hagiwara FlashGate DUAL unit.  However, bus traces reveal that neither
230  * MacOS nor Windows checks the status after clearing a halt.
231  *
232  * Since many vendors in this space limit their testing to interoperability
233  * with these two OSes, specification violations like this one are common.
234  */
235 int usb_stor_clear_halt(struct us_data *us, unsigned int pipe)
236 {
237 	int result;
238 	int endp = usb_pipeendpoint(pipe);
239 
240 	if (usb_pipein (pipe))
241 		endp |= USB_DIR_IN;
242 
243 	result = usb_stor_control_msg(us, us->send_ctrl_pipe,
244 		USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT,
245 		USB_ENDPOINT_HALT, endp,
246 		NULL, 0, 3*HZ);
247 
248 	if (result >= 0)
249 		usb_reset_endpoint(us->pusb_dev, endp);
250 
251 	US_DEBUGP("%s: result = %d\n", __func__, result);
252 	return result;
253 }
254 EXPORT_SYMBOL_GPL(usb_stor_clear_halt);
255 
256 
257 /*
258  * Interpret the results of a URB transfer
259  *
260  * This function prints appropriate debugging messages, clears halts on
261  * non-control endpoints, and translates the status to the corresponding
262  * USB_STOR_XFER_xxx return code.
263  */
264 static int interpret_urb_result(struct us_data *us, unsigned int pipe,
265 		unsigned int length, int result, unsigned int partial)
266 {
267 	US_DEBUGP("Status code %d; transferred %u/%u\n",
268 			result, partial, length);
269 	switch (result) {
270 
271 	/* no error code; did we send all the data? */
272 	case 0:
273 		if (partial != length) {
274 			US_DEBUGP("-- short transfer\n");
275 			return USB_STOR_XFER_SHORT;
276 		}
277 
278 		US_DEBUGP("-- transfer complete\n");
279 		return USB_STOR_XFER_GOOD;
280 
281 	/* stalled */
282 	case -EPIPE:
283 		/* for control endpoints, (used by CB[I]) a stall indicates
284 		 * a failed command */
285 		if (usb_pipecontrol(pipe)) {
286 			US_DEBUGP("-- stall on control pipe\n");
287 			return USB_STOR_XFER_STALLED;
288 		}
289 
290 		/* for other sorts of endpoint, clear the stall */
291 		US_DEBUGP("clearing endpoint halt for pipe 0x%x\n", pipe);
292 		if (usb_stor_clear_halt(us, pipe) < 0)
293 			return USB_STOR_XFER_ERROR;
294 		return USB_STOR_XFER_STALLED;
295 
296 	/* babble - the device tried to send more than we wanted to read */
297 	case -EOVERFLOW:
298 		US_DEBUGP("-- babble\n");
299 		return USB_STOR_XFER_LONG;
300 
301 	/* the transfer was cancelled by abort, disconnect, or timeout */
302 	case -ECONNRESET:
303 		US_DEBUGP("-- transfer cancelled\n");
304 		return USB_STOR_XFER_ERROR;
305 
306 	/* short scatter-gather read transfer */
307 	case -EREMOTEIO:
308 		US_DEBUGP("-- short read transfer\n");
309 		return USB_STOR_XFER_SHORT;
310 
311 	/* abort or disconnect in progress */
312 	case -EIO:
313 		US_DEBUGP("-- abort or disconnect in progress\n");
314 		return USB_STOR_XFER_ERROR;
315 
316 	/* the catch-all error case */
317 	default:
318 		US_DEBUGP("-- unknown error\n");
319 		return USB_STOR_XFER_ERROR;
320 	}
321 }
322 
323 /*
324  * Transfer one control message, without timeouts, but allowing early
325  * termination.  Return codes are USB_STOR_XFER_xxx.
326  */
327 int usb_stor_ctrl_transfer(struct us_data *us, unsigned int pipe,
328 		u8 request, u8 requesttype, u16 value, u16 index,
329 		void *data, u16 size)
330 {
331 	int result;
332 
333 	US_DEBUGP("%s: rq=%02x rqtype=%02x value=%04x index=%02x len=%u\n",
334 			__func__, request, requesttype,
335 			value, index, size);
336 
337 	/* fill in the devrequest structure */
338 	us->cr->bRequestType = requesttype;
339 	us->cr->bRequest = request;
340 	us->cr->wValue = cpu_to_le16(value);
341 	us->cr->wIndex = cpu_to_le16(index);
342 	us->cr->wLength = cpu_to_le16(size);
343 
344 	/* fill and submit the URB */
345 	usb_fill_control_urb(us->current_urb, us->pusb_dev, pipe,
346 			 (unsigned char*) us->cr, data, size,
347 			 usb_stor_blocking_completion, NULL);
348 	result = usb_stor_msg_common(us, 0);
349 
350 	return interpret_urb_result(us, pipe, size, result,
351 			us->current_urb->actual_length);
352 }
353 EXPORT_SYMBOL_GPL(usb_stor_ctrl_transfer);
354 
355 /*
356  * Receive one interrupt buffer, without timeouts, but allowing early
357  * termination.  Return codes are USB_STOR_XFER_xxx.
358  *
359  * This routine always uses us->recv_intr_pipe as the pipe and
360  * us->ep_bInterval as the interrupt interval.
361  */
362 static int usb_stor_intr_transfer(struct us_data *us, void *buf,
363 				  unsigned int length)
364 {
365 	int result;
366 	unsigned int pipe = us->recv_intr_pipe;
367 	unsigned int maxp;
368 
369 	US_DEBUGP("%s: xfer %u bytes\n", __func__, length);
370 
371 	/* calculate the max packet size */
372 	maxp = usb_maxpacket(us->pusb_dev, pipe, usb_pipeout(pipe));
373 	if (maxp > length)
374 		maxp = length;
375 
376 	/* fill and submit the URB */
377 	usb_fill_int_urb(us->current_urb, us->pusb_dev, pipe, buf,
378 			maxp, usb_stor_blocking_completion, NULL,
379 			us->ep_bInterval);
380 	result = usb_stor_msg_common(us, 0);
381 
382 	return interpret_urb_result(us, pipe, length, result,
383 			us->current_urb->actual_length);
384 }
385 
386 /*
387  * Transfer one buffer via bulk pipe, without timeouts, but allowing early
388  * termination.  Return codes are USB_STOR_XFER_xxx.  If the bulk pipe
389  * stalls during the transfer, the halt is automatically cleared.
390  */
391 int usb_stor_bulk_transfer_buf(struct us_data *us, unsigned int pipe,
392 	void *buf, unsigned int length, unsigned int *act_len)
393 {
394 	int result;
395 
396 	US_DEBUGP("%s: xfer %u bytes\n", __func__, length);
397 
398 	/* fill and submit the URB */
399 	usb_fill_bulk_urb(us->current_urb, us->pusb_dev, pipe, buf, length,
400 		      usb_stor_blocking_completion, NULL);
401 	result = usb_stor_msg_common(us, 0);
402 
403 	/* store the actual length of the data transferred */
404 	if (act_len)
405 		*act_len = us->current_urb->actual_length;
406 	return interpret_urb_result(us, pipe, length, result,
407 			us->current_urb->actual_length);
408 }
409 EXPORT_SYMBOL_GPL(usb_stor_bulk_transfer_buf);
410 
411 /*
412  * Transfer a scatter-gather list via bulk transfer
413  *
414  * This function does basically the same thing as usb_stor_bulk_transfer_buf()
415  * above, but it uses the usbcore scatter-gather library.
416  */
417 static int usb_stor_bulk_transfer_sglist(struct us_data *us, unsigned int pipe,
418 		struct scatterlist *sg, int num_sg, unsigned int length,
419 		unsigned int *act_len)
420 {
421 	int result;
422 
423 	/* don't submit s-g requests during abort processing */
424 	if (test_bit(US_FLIDX_ABORTING, &us->dflags))
425 		return USB_STOR_XFER_ERROR;
426 
427 	/* initialize the scatter-gather request block */
428 	US_DEBUGP("%s: xfer %u bytes, %d entries\n", __func__,
429 			length, num_sg);
430 	result = usb_sg_init(&us->current_sg, us->pusb_dev, pipe, 0,
431 			sg, num_sg, length, GFP_NOIO);
432 	if (result) {
433 		US_DEBUGP("usb_sg_init returned %d\n", result);
434 		return USB_STOR_XFER_ERROR;
435 	}
436 
437 	/* since the block has been initialized successfully, it's now
438 	 * okay to cancel it */
439 	set_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
440 
441 	/* did an abort occur during the submission? */
442 	if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
443 
444 		/* cancel the request, if it hasn't been cancelled already */
445 		if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
446 			US_DEBUGP("-- cancelling sg request\n");
447 			usb_sg_cancel(&us->current_sg);
448 		}
449 	}
450 
451 	/* wait for the completion of the transfer */
452 	usb_sg_wait(&us->current_sg);
453 	clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
454 
455 	result = us->current_sg.status;
456 	if (act_len)
457 		*act_len = us->current_sg.bytes;
458 	return interpret_urb_result(us, pipe, length, result,
459 			us->current_sg.bytes);
460 }
461 
462 /*
463  * Common used function. Transfer a complete command
464  * via usb_stor_bulk_transfer_sglist() above. Set cmnd resid
465  */
466 int usb_stor_bulk_srb(struct us_data* us, unsigned int pipe,
467 		      struct scsi_cmnd* srb)
468 {
469 	unsigned int partial;
470 	int result = usb_stor_bulk_transfer_sglist(us, pipe, scsi_sglist(srb),
471 				      scsi_sg_count(srb), scsi_bufflen(srb),
472 				      &partial);
473 
474 	scsi_set_resid(srb, scsi_bufflen(srb) - partial);
475 	return result;
476 }
477 EXPORT_SYMBOL_GPL(usb_stor_bulk_srb);
478 
479 /*
480  * Transfer an entire SCSI command's worth of data payload over the bulk
481  * pipe.
482  *
483  * Note that this uses usb_stor_bulk_transfer_buf() and
484  * usb_stor_bulk_transfer_sglist() to achieve its goals --
485  * this function simply determines whether we're going to use
486  * scatter-gather or not, and acts appropriately.
487  */
488 int usb_stor_bulk_transfer_sg(struct us_data* us, unsigned int pipe,
489 		void *buf, unsigned int length_left, int use_sg, int *residual)
490 {
491 	int result;
492 	unsigned int partial;
493 
494 	/* are we scatter-gathering? */
495 	if (use_sg) {
496 		/* use the usb core scatter-gather primitives */
497 		result = usb_stor_bulk_transfer_sglist(us, pipe,
498 				(struct scatterlist *) buf, use_sg,
499 				length_left, &partial);
500 		length_left -= partial;
501 	} else {
502 		/* no scatter-gather, just make the request */
503 		result = usb_stor_bulk_transfer_buf(us, pipe, buf,
504 				length_left, &partial);
505 		length_left -= partial;
506 	}
507 
508 	/* store the residual and return the error code */
509 	if (residual)
510 		*residual = length_left;
511 	return result;
512 }
513 EXPORT_SYMBOL_GPL(usb_stor_bulk_transfer_sg);
514 
515 /***********************************************************************
516  * Transport routines
517  ***********************************************************************/
518 
519 /* There are so many devices that report the capacity incorrectly,
520  * this routine was written to counteract some of the resulting
521  * problems.
522  */
523 static void last_sector_hacks(struct us_data *us, struct scsi_cmnd *srb)
524 {
525 	struct gendisk *disk;
526 	struct scsi_disk *sdkp;
527 	u32 sector;
528 
529 	/* To Report "Medium Error: Record Not Found */
530 	static unsigned char record_not_found[18] = {
531 		[0]	= 0x70,			/* current error */
532 		[2]	= MEDIUM_ERROR,		/* = 0x03 */
533 		[7]	= 0x0a,			/* additional length */
534 		[12]	= 0x14			/* Record Not Found */
535 	};
536 
537 	/* If last-sector problems can't occur, whether because the
538 	 * capacity was already decremented or because the device is
539 	 * known to report the correct capacity, then we don't need
540 	 * to do anything.
541 	 */
542 	if (!us->use_last_sector_hacks)
543 		return;
544 
545 	/* Was this command a READ(10) or a WRITE(10)? */
546 	if (srb->cmnd[0] != READ_10 && srb->cmnd[0] != WRITE_10)
547 		goto done;
548 
549 	/* Did this command access the last sector? */
550 	sector = (srb->cmnd[2] << 24) | (srb->cmnd[3] << 16) |
551 			(srb->cmnd[4] << 8) | (srb->cmnd[5]);
552 	disk = srb->request->rq_disk;
553 	if (!disk)
554 		goto done;
555 	sdkp = scsi_disk(disk);
556 	if (!sdkp)
557 		goto done;
558 	if (sector + 1 != sdkp->capacity)
559 		goto done;
560 
561 	if (srb->result == SAM_STAT_GOOD && scsi_get_resid(srb) == 0) {
562 
563 		/* The command succeeded.  We know this device doesn't
564 		 * have the last-sector bug, so stop checking it.
565 		 */
566 		us->use_last_sector_hacks = 0;
567 
568 	} else {
569 		/* The command failed.  Allow up to 3 retries in case this
570 		 * is some normal sort of failure.  After that, assume the
571 		 * capacity is wrong and we're trying to access the sector
572 		 * beyond the end.  Replace the result code and sense data
573 		 * with values that will cause the SCSI core to fail the
574 		 * command immediately, instead of going into an infinite
575 		 * (or even just a very long) retry loop.
576 		 */
577 		if (++us->last_sector_retries < 3)
578 			return;
579 		srb->result = SAM_STAT_CHECK_CONDITION;
580 		memcpy(srb->sense_buffer, record_not_found,
581 				sizeof(record_not_found));
582 	}
583 
584  done:
585 	/* Don't reset the retry counter for TEST UNIT READY commands,
586 	 * because they get issued after device resets which might be
587 	 * caused by a failed last-sector access.
588 	 */
589 	if (srb->cmnd[0] != TEST_UNIT_READY)
590 		us->last_sector_retries = 0;
591 }
592 
593 /* Invoke the transport and basic error-handling/recovery methods
594  *
595  * This is used by the protocol layers to actually send the message to
596  * the device and receive the response.
597  */
598 void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
599 {
600 	int need_auto_sense;
601 	int result;
602 
603 	/* send the command to the transport layer */
604 	scsi_set_resid(srb, 0);
605 	result = us->transport(srb, us);
606 
607 	/* if the command gets aborted by the higher layers, we need to
608 	 * short-circuit all other processing
609 	 */
610 	if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
611 		US_DEBUGP("-- command was aborted\n");
612 		srb->result = DID_ABORT << 16;
613 		goto Handle_Errors;
614 	}
615 
616 	/* if there is a transport error, reset and don't auto-sense */
617 	if (result == USB_STOR_TRANSPORT_ERROR) {
618 		US_DEBUGP("-- transport indicates error, resetting\n");
619 		srb->result = DID_ERROR << 16;
620 		goto Handle_Errors;
621 	}
622 
623 	/* if the transport provided its own sense data, don't auto-sense */
624 	if (result == USB_STOR_TRANSPORT_NO_SENSE) {
625 		srb->result = SAM_STAT_CHECK_CONDITION;
626 		last_sector_hacks(us, srb);
627 		return;
628 	}
629 
630 	srb->result = SAM_STAT_GOOD;
631 
632 	/* Determine if we need to auto-sense
633 	 *
634 	 * I normally don't use a flag like this, but it's almost impossible
635 	 * to understand what's going on here if I don't.
636 	 */
637 	need_auto_sense = 0;
638 
639 	/*
640 	 * If we're running the CB transport, which is incapable
641 	 * of determining status on its own, we will auto-sense
642 	 * unless the operation involved a data-in transfer.  Devices
643 	 * can signal most data-in errors by stalling the bulk-in pipe.
644 	 */
645 	if ((us->protocol == USB_PR_CB || us->protocol == USB_PR_DPCM_USB) &&
646 			srb->sc_data_direction != DMA_FROM_DEVICE) {
647 		US_DEBUGP("-- CB transport device requiring auto-sense\n");
648 		need_auto_sense = 1;
649 	}
650 
651 	/*
652 	 * If we have a failure, we're going to do a REQUEST_SENSE
653 	 * automatically.  Note that we differentiate between a command
654 	 * "failure" and an "error" in the transport mechanism.
655 	 */
656 	if (result == USB_STOR_TRANSPORT_FAILED) {
657 		US_DEBUGP("-- transport indicates command failure\n");
658 		need_auto_sense = 1;
659 	}
660 
661 	/*
662 	 * Determine if this device is SAT by seeing if the
663 	 * command executed successfully.  Otherwise we'll have
664 	 * to wait for at least one CHECK_CONDITION to determine
665 	 * SANE_SENSE support
666 	 */
667 	if (unlikely((srb->cmnd[0] == ATA_16 || srb->cmnd[0] == ATA_12) &&
668 	    result == USB_STOR_TRANSPORT_GOOD &&
669 	    !(us->fflags & US_FL_SANE_SENSE) &&
670 	    !(us->fflags & US_FL_BAD_SENSE) &&
671 	    !(srb->cmnd[2] & 0x20))) {
672 		US_DEBUGP("-- SAT supported, increasing auto-sense\n");
673 		us->fflags |= US_FL_SANE_SENSE;
674 	}
675 
676 	/*
677 	 * A short transfer on a command where we don't expect it
678 	 * is unusual, but it doesn't mean we need to auto-sense.
679 	 */
680 	if ((scsi_get_resid(srb) > 0) &&
681 	    !((srb->cmnd[0] == REQUEST_SENSE) ||
682 	      (srb->cmnd[0] == INQUIRY) ||
683 	      (srb->cmnd[0] == MODE_SENSE) ||
684 	      (srb->cmnd[0] == LOG_SENSE) ||
685 	      (srb->cmnd[0] == MODE_SENSE_10))) {
686 		US_DEBUGP("-- unexpectedly short transfer\n");
687 	}
688 
689 	/* Now, if we need to do the auto-sense, let's do it */
690 	if (need_auto_sense) {
691 		int temp_result;
692 		struct scsi_eh_save ses;
693 		int sense_size = US_SENSE_SIZE;
694 
695 		/* device supports and needs bigger sense buffer */
696 		if (us->fflags & US_FL_SANE_SENSE)
697 			sense_size = ~0;
698 Retry_Sense:
699 		US_DEBUGP("Issuing auto-REQUEST_SENSE\n");
700 
701 		scsi_eh_prep_cmnd(srb, &ses, NULL, 0, sense_size);
702 
703 		/* FIXME: we must do the protocol translation here */
704 		if (us->subclass == USB_SC_RBC || us->subclass == USB_SC_SCSI ||
705 				us->subclass == USB_SC_CYP_ATACB)
706 			srb->cmd_len = 6;
707 		else
708 			srb->cmd_len = 12;
709 
710 		/* issue the auto-sense command */
711 		scsi_set_resid(srb, 0);
712 		temp_result = us->transport(us->srb, us);
713 
714 		/* let's clean up right away */
715 		scsi_eh_restore_cmnd(srb, &ses);
716 
717 		if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
718 			US_DEBUGP("-- auto-sense aborted\n");
719 			srb->result = DID_ABORT << 16;
720 
721 			/* If SANE_SENSE caused this problem, disable it */
722 			if (sense_size != US_SENSE_SIZE) {
723 				us->fflags &= ~US_FL_SANE_SENSE;
724 				us->fflags |= US_FL_BAD_SENSE;
725 			}
726 			goto Handle_Errors;
727 		}
728 
729 		/* Some devices claim to support larger sense but fail when
730 		 * trying to request it. When a transport failure happens
731 		 * using US_FS_SANE_SENSE, we always retry with a standard
732 		 * (small) sense request. This fixes some USB GSM modems
733 		 */
734 		if (temp_result == USB_STOR_TRANSPORT_FAILED &&
735 				sense_size != US_SENSE_SIZE) {
736 			US_DEBUGP("-- auto-sense failure, retry small sense\n");
737 			sense_size = US_SENSE_SIZE;
738 			us->fflags &= ~US_FL_SANE_SENSE;
739 			us->fflags |= US_FL_BAD_SENSE;
740 			goto Retry_Sense;
741 		}
742 
743 		/* Other failures */
744 		if (temp_result != USB_STOR_TRANSPORT_GOOD) {
745 			US_DEBUGP("-- auto-sense failure\n");
746 
747 			/* we skip the reset if this happens to be a
748 			 * multi-target device, since failure of an
749 			 * auto-sense is perfectly valid
750 			 */
751 			srb->result = DID_ERROR << 16;
752 			if (!(us->fflags & US_FL_SCM_MULT_TARG))
753 				goto Handle_Errors;
754 			return;
755 		}
756 
757 		/* If the sense data returned is larger than 18-bytes then we
758 		 * assume this device supports requesting more in the future.
759 		 * The response code must be 70h through 73h inclusive.
760 		 */
761 		if (srb->sense_buffer[7] > (US_SENSE_SIZE - 8) &&
762 		    !(us->fflags & US_FL_SANE_SENSE) &&
763 		    !(us->fflags & US_FL_BAD_SENSE) &&
764 		    (srb->sense_buffer[0] & 0x7C) == 0x70) {
765 			US_DEBUGP("-- SANE_SENSE support enabled\n");
766 			us->fflags |= US_FL_SANE_SENSE;
767 
768 			/* Indicate to the user that we truncated their sense
769 			 * because we didn't know it supported larger sense.
770 			 */
771 			US_DEBUGP("-- Sense data truncated to %i from %i\n",
772 			          US_SENSE_SIZE,
773 			          srb->sense_buffer[7] + 8);
774 			srb->sense_buffer[7] = (US_SENSE_SIZE - 8);
775 		}
776 
777 		US_DEBUGP("-- Result from auto-sense is %d\n", temp_result);
778 		US_DEBUGP("-- code: 0x%x, key: 0x%x, ASC: 0x%x, ASCQ: 0x%x\n",
779 			  srb->sense_buffer[0],
780 			  srb->sense_buffer[2] & 0xf,
781 			  srb->sense_buffer[12],
782 			  srb->sense_buffer[13]);
783 #ifdef CONFIG_USB_STORAGE_DEBUG
784 		usb_stor_show_sense(
785 			  srb->sense_buffer[2] & 0xf,
786 			  srb->sense_buffer[12],
787 			  srb->sense_buffer[13]);
788 #endif
789 
790 		/* set the result so the higher layers expect this data */
791 		srb->result = SAM_STAT_CHECK_CONDITION;
792 
793 		/* We often get empty sense data.  This could indicate that
794 		 * everything worked or that there was an unspecified
795 		 * problem.  We have to decide which.
796 		 */
797 		if (	/* Filemark 0, ignore EOM, ILI 0, no sense */
798 				(srb->sense_buffer[2] & 0xaf) == 0 &&
799 			/* No ASC or ASCQ */
800 				srb->sense_buffer[12] == 0 &&
801 				srb->sense_buffer[13] == 0) {
802 
803 			/* If things are really okay, then let's show that.
804 			 * Zero out the sense buffer so the higher layers
805 			 * won't realize we did an unsolicited auto-sense.
806 			 */
807 			if (result == USB_STOR_TRANSPORT_GOOD) {
808 				srb->result = SAM_STAT_GOOD;
809 				srb->sense_buffer[0] = 0x0;
810 
811 			/* If there was a problem, report an unspecified
812 			 * hardware error to prevent the higher layers from
813 			 * entering an infinite retry loop.
814 			 */
815 			} else {
816 				srb->result = DID_ERROR << 16;
817 				srb->sense_buffer[2] = HARDWARE_ERROR;
818 			}
819 		}
820 	}
821 
822 	/* Did we transfer less than the minimum amount required? */
823 	if ((srb->result == SAM_STAT_GOOD || srb->sense_buffer[2] == 0) &&
824 			scsi_bufflen(srb) - scsi_get_resid(srb) < srb->underflow)
825 		srb->result = DID_ERROR << 16;
826 
827 	last_sector_hacks(us, srb);
828 	return;
829 
830 	/* Error and abort processing: try to resynchronize with the device
831 	 * by issuing a port reset.  If that fails, try a class-specific
832 	 * device reset. */
833   Handle_Errors:
834 
835 	/* Set the RESETTING bit, and clear the ABORTING bit so that
836 	 * the reset may proceed. */
837 	scsi_lock(us_to_host(us));
838 	set_bit(US_FLIDX_RESETTING, &us->dflags);
839 	clear_bit(US_FLIDX_ABORTING, &us->dflags);
840 	scsi_unlock(us_to_host(us));
841 
842 	/* We must release the device lock because the pre_reset routine
843 	 * will want to acquire it. */
844 	mutex_unlock(&us->dev_mutex);
845 	result = usb_stor_port_reset(us);
846 	mutex_lock(&us->dev_mutex);
847 
848 	if (result < 0) {
849 		scsi_lock(us_to_host(us));
850 		usb_stor_report_device_reset(us);
851 		scsi_unlock(us_to_host(us));
852 		us->transport_reset(us);
853 	}
854 	clear_bit(US_FLIDX_RESETTING, &us->dflags);
855 	last_sector_hacks(us, srb);
856 }
857 
858 /* Stop the current URB transfer */
859 void usb_stor_stop_transport(struct us_data *us)
860 {
861 	US_DEBUGP("%s called\n", __func__);
862 
863 	/* If the state machine is blocked waiting for an URB,
864 	 * let's wake it up.  The test_and_clear_bit() call
865 	 * guarantees that if a URB has just been submitted,
866 	 * it won't be cancelled more than once. */
867 	if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
868 		US_DEBUGP("-- cancelling URB\n");
869 		usb_unlink_urb(us->current_urb);
870 	}
871 
872 	/* If we are waiting for a scatter-gather operation, cancel it. */
873 	if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
874 		US_DEBUGP("-- cancelling sg request\n");
875 		usb_sg_cancel(&us->current_sg);
876 	}
877 }
878 
879 /*
880  * Control/Bulk and Control/Bulk/Interrupt transport
881  */
882 
883 int usb_stor_CB_transport(struct scsi_cmnd *srb, struct us_data *us)
884 {
885 	unsigned int transfer_length = scsi_bufflen(srb);
886 	unsigned int pipe = 0;
887 	int result;
888 
889 	/* COMMAND STAGE */
890 	/* let's send the command via the control pipe */
891 	result = usb_stor_ctrl_transfer(us, us->send_ctrl_pipe,
892 				      US_CBI_ADSC,
893 				      USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0,
894 				      us->ifnum, srb->cmnd, srb->cmd_len);
895 
896 	/* check the return code for the command */
897 	US_DEBUGP("Call to usb_stor_ctrl_transfer() returned %d\n", result);
898 
899 	/* if we stalled the command, it means command failed */
900 	if (result == USB_STOR_XFER_STALLED) {
901 		return USB_STOR_TRANSPORT_FAILED;
902 	}
903 
904 	/* Uh oh... serious problem here */
905 	if (result != USB_STOR_XFER_GOOD) {
906 		return USB_STOR_TRANSPORT_ERROR;
907 	}
908 
909 	/* DATA STAGE */
910 	/* transfer the data payload for this command, if one exists*/
911 	if (transfer_length) {
912 		pipe = srb->sc_data_direction == DMA_FROM_DEVICE ?
913 				us->recv_bulk_pipe : us->send_bulk_pipe;
914 		result = usb_stor_bulk_srb(us, pipe, srb);
915 		US_DEBUGP("CBI data stage result is 0x%x\n", result);
916 
917 		/* if we stalled the data transfer it means command failed */
918 		if (result == USB_STOR_XFER_STALLED)
919 			return USB_STOR_TRANSPORT_FAILED;
920 		if (result > USB_STOR_XFER_STALLED)
921 			return USB_STOR_TRANSPORT_ERROR;
922 	}
923 
924 	/* STATUS STAGE */
925 
926 	/* NOTE: CB does not have a status stage.  Silly, I know.  So
927 	 * we have to catch this at a higher level.
928 	 */
929 	if (us->protocol != USB_PR_CBI)
930 		return USB_STOR_TRANSPORT_GOOD;
931 
932 	result = usb_stor_intr_transfer(us, us->iobuf, 2);
933 	US_DEBUGP("Got interrupt data (0x%x, 0x%x)\n",
934 			us->iobuf[0], us->iobuf[1]);
935 	if (result != USB_STOR_XFER_GOOD)
936 		return USB_STOR_TRANSPORT_ERROR;
937 
938 	/* UFI gives us ASC and ASCQ, like a request sense
939 	 *
940 	 * REQUEST_SENSE and INQUIRY don't affect the sense data on UFI
941 	 * devices, so we ignore the information for those commands.  Note
942 	 * that this means we could be ignoring a real error on these
943 	 * commands, but that can't be helped.
944 	 */
945 	if (us->subclass == USB_SC_UFI) {
946 		if (srb->cmnd[0] == REQUEST_SENSE ||
947 		    srb->cmnd[0] == INQUIRY)
948 			return USB_STOR_TRANSPORT_GOOD;
949 		if (us->iobuf[0])
950 			goto Failed;
951 		return USB_STOR_TRANSPORT_GOOD;
952 	}
953 
954 	/* If not UFI, we interpret the data as a result code
955 	 * The first byte should always be a 0x0.
956 	 *
957 	 * Some bogus devices don't follow that rule.  They stuff the ASC
958 	 * into the first byte -- so if it's non-zero, call it a failure.
959 	 */
960 	if (us->iobuf[0]) {
961 		US_DEBUGP("CBI IRQ data showed reserved bType 0x%x\n",
962 				us->iobuf[0]);
963 		goto Failed;
964 
965 	}
966 
967 	/* The second byte & 0x0F should be 0x0 for good, otherwise error */
968 	switch (us->iobuf[1] & 0x0F) {
969 		case 0x00:
970 			return USB_STOR_TRANSPORT_GOOD;
971 		case 0x01:
972 			goto Failed;
973 	}
974 	return USB_STOR_TRANSPORT_ERROR;
975 
976 	/* the CBI spec requires that the bulk pipe must be cleared
977 	 * following any data-in/out command failure (section 2.4.3.1.3)
978 	 */
979   Failed:
980 	if (pipe)
981 		usb_stor_clear_halt(us, pipe);
982 	return USB_STOR_TRANSPORT_FAILED;
983 }
984 EXPORT_SYMBOL_GPL(usb_stor_CB_transport);
985 
986 /*
987  * Bulk only transport
988  */
989 
990 /* Determine what the maximum LUN supported is */
991 int usb_stor_Bulk_max_lun(struct us_data *us)
992 {
993 	int result;
994 
995 	/* issue the command */
996 	us->iobuf[0] = 0;
997 	result = usb_stor_control_msg(us, us->recv_ctrl_pipe,
998 				 US_BULK_GET_MAX_LUN,
999 				 USB_DIR_IN | USB_TYPE_CLASS |
1000 				 USB_RECIP_INTERFACE,
1001 				 0, us->ifnum, us->iobuf, 1, 10*HZ);
1002 
1003 	US_DEBUGP("GetMaxLUN command result is %d, data is %d\n",
1004 		  result, us->iobuf[0]);
1005 
1006 	/* if we have a successful request, return the result */
1007 	if (result > 0)
1008 		return us->iobuf[0];
1009 
1010 	/*
1011 	 * Some devices don't like GetMaxLUN.  They may STALL the control
1012 	 * pipe, they may return a zero-length result, they may do nothing at
1013 	 * all and timeout, or they may fail in even more bizarrely creative
1014 	 * ways.  In these cases the best approach is to use the default
1015 	 * value: only one LUN.
1016 	 */
1017 	return 0;
1018 }
1019 
1020 int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us)
1021 {
1022 	struct bulk_cb_wrap *bcb = (struct bulk_cb_wrap *) us->iobuf;
1023 	struct bulk_cs_wrap *bcs = (struct bulk_cs_wrap *) us->iobuf;
1024 	unsigned int transfer_length = scsi_bufflen(srb);
1025 	unsigned int residue;
1026 	int result;
1027 	int fake_sense = 0;
1028 	unsigned int cswlen;
1029 	unsigned int cbwlen = US_BULK_CB_WRAP_LEN;
1030 
1031 	/* Take care of BULK32 devices; set extra byte to 0 */
1032 	if (unlikely(us->fflags & US_FL_BULK32)) {
1033 		cbwlen = 32;
1034 		us->iobuf[31] = 0;
1035 	}
1036 
1037 	/* set up the command wrapper */
1038 	bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
1039 	bcb->DataTransferLength = cpu_to_le32(transfer_length);
1040 	bcb->Flags = srb->sc_data_direction == DMA_FROM_DEVICE ? 1 << 7 : 0;
1041 	bcb->Tag = ++us->tag;
1042 	bcb->Lun = srb->device->lun;
1043 	if (us->fflags & US_FL_SCM_MULT_TARG)
1044 		bcb->Lun |= srb->device->id << 4;
1045 	bcb->Length = srb->cmd_len;
1046 
1047 	/* copy the command payload */
1048 	memset(bcb->CDB, 0, sizeof(bcb->CDB));
1049 	memcpy(bcb->CDB, srb->cmnd, bcb->Length);
1050 
1051 	/* send it to out endpoint */
1052 	US_DEBUGP("Bulk Command S 0x%x T 0x%x L %d F %d Trg %d LUN %d CL %d\n",
1053 			le32_to_cpu(bcb->Signature), bcb->Tag,
1054 			le32_to_cpu(bcb->DataTransferLength), bcb->Flags,
1055 			(bcb->Lun >> 4), (bcb->Lun & 0x0F),
1056 			bcb->Length);
1057 	result = usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
1058 				bcb, cbwlen, NULL);
1059 	US_DEBUGP("Bulk command transfer result=%d\n", result);
1060 	if (result != USB_STOR_XFER_GOOD)
1061 		return USB_STOR_TRANSPORT_ERROR;
1062 
1063 	/* DATA STAGE */
1064 	/* send/receive data payload, if there is any */
1065 
1066 	/* Some USB-IDE converter chips need a 100us delay between the
1067 	 * command phase and the data phase.  Some devices need a little
1068 	 * more than that, probably because of clock rate inaccuracies. */
1069 	if (unlikely(us->fflags & US_FL_GO_SLOW))
1070 		udelay(125);
1071 
1072 	if (transfer_length) {
1073 		unsigned int pipe = srb->sc_data_direction == DMA_FROM_DEVICE ?
1074 				us->recv_bulk_pipe : us->send_bulk_pipe;
1075 		result = usb_stor_bulk_srb(us, pipe, srb);
1076 		US_DEBUGP("Bulk data transfer result 0x%x\n", result);
1077 		if (result == USB_STOR_XFER_ERROR)
1078 			return USB_STOR_TRANSPORT_ERROR;
1079 
1080 		/* If the device tried to send back more data than the
1081 		 * amount requested, the spec requires us to transfer
1082 		 * the CSW anyway.  Since there's no point retrying the
1083 		 * the command, we'll return fake sense data indicating
1084 		 * Illegal Request, Invalid Field in CDB.
1085 		 */
1086 		if (result == USB_STOR_XFER_LONG)
1087 			fake_sense = 1;
1088 	}
1089 
1090 	/* See flow chart on pg 15 of the Bulk Only Transport spec for
1091 	 * an explanation of how this code works.
1092 	 */
1093 
1094 	/* get CSW for device status */
1095 	US_DEBUGP("Attempting to get CSW...\n");
1096 	result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1097 				bcs, US_BULK_CS_WRAP_LEN, &cswlen);
1098 
1099 	/* Some broken devices add unnecessary zero-length packets to the
1100 	 * end of their data transfers.  Such packets show up as 0-length
1101 	 * CSWs.  If we encounter such a thing, try to read the CSW again.
1102 	 */
1103 	if (result == USB_STOR_XFER_SHORT && cswlen == 0) {
1104 		US_DEBUGP("Received 0-length CSW; retrying...\n");
1105 		result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1106 				bcs, US_BULK_CS_WRAP_LEN, &cswlen);
1107 	}
1108 
1109 	/* did the attempt to read the CSW fail? */
1110 	if (result == USB_STOR_XFER_STALLED) {
1111 
1112 		/* get the status again */
1113 		US_DEBUGP("Attempting to get CSW (2nd try)...\n");
1114 		result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1115 				bcs, US_BULK_CS_WRAP_LEN, NULL);
1116 	}
1117 
1118 	/* if we still have a failure at this point, we're in trouble */
1119 	US_DEBUGP("Bulk status result = %d\n", result);
1120 	if (result != USB_STOR_XFER_GOOD)
1121 		return USB_STOR_TRANSPORT_ERROR;
1122 
1123 	/* check bulk status */
1124 	residue = le32_to_cpu(bcs->Residue);
1125 	US_DEBUGP("Bulk Status S 0x%x T 0x%x R %u Stat 0x%x\n",
1126 			le32_to_cpu(bcs->Signature), bcs->Tag,
1127 			residue, bcs->Status);
1128 	if (!(bcs->Tag == us->tag || (us->fflags & US_FL_BULK_IGNORE_TAG)) ||
1129 		bcs->Status > US_BULK_STAT_PHASE) {
1130 		US_DEBUGP("Bulk logical error\n");
1131 		return USB_STOR_TRANSPORT_ERROR;
1132 	}
1133 
1134 	/* Some broken devices report odd signatures, so we do not check them
1135 	 * for validity against the spec. We store the first one we see,
1136 	 * and check subsequent transfers for validity against this signature.
1137 	 */
1138 	if (!us->bcs_signature) {
1139 		us->bcs_signature = bcs->Signature;
1140 		if (us->bcs_signature != cpu_to_le32(US_BULK_CS_SIGN))
1141 			US_DEBUGP("Learnt BCS signature 0x%08X\n",
1142 					le32_to_cpu(us->bcs_signature));
1143 	} else if (bcs->Signature != us->bcs_signature) {
1144 		US_DEBUGP("Signature mismatch: got %08X, expecting %08X\n",
1145 			  le32_to_cpu(bcs->Signature),
1146 			  le32_to_cpu(us->bcs_signature));
1147 		return USB_STOR_TRANSPORT_ERROR;
1148 	}
1149 
1150 	/* try to compute the actual residue, based on how much data
1151 	 * was really transferred and what the device tells us */
1152 	if (residue && !(us->fflags & US_FL_IGNORE_RESIDUE)) {
1153 
1154 		/* Heuristically detect devices that generate bogus residues
1155 		 * by seeing what happens with INQUIRY and READ CAPACITY
1156 		 * commands.
1157 		 */
1158 		if (bcs->Status == US_BULK_STAT_OK &&
1159 				scsi_get_resid(srb) == 0 &&
1160 					((srb->cmnd[0] == INQUIRY &&
1161 						transfer_length == 36) ||
1162 					(srb->cmnd[0] == READ_CAPACITY &&
1163 						transfer_length == 8))) {
1164 			us->fflags |= US_FL_IGNORE_RESIDUE;
1165 
1166 		} else {
1167 			residue = min(residue, transfer_length);
1168 			scsi_set_resid(srb, max(scsi_get_resid(srb),
1169 			                                       (int) residue));
1170 		}
1171 	}
1172 
1173 	/* based on the status code, we report good or bad */
1174 	switch (bcs->Status) {
1175 		case US_BULK_STAT_OK:
1176 			/* device babbled -- return fake sense data */
1177 			if (fake_sense) {
1178 				memcpy(srb->sense_buffer,
1179 				       usb_stor_sense_invalidCDB,
1180 				       sizeof(usb_stor_sense_invalidCDB));
1181 				return USB_STOR_TRANSPORT_NO_SENSE;
1182 			}
1183 
1184 			/* command good -- note that data could be short */
1185 			return USB_STOR_TRANSPORT_GOOD;
1186 
1187 		case US_BULK_STAT_FAIL:
1188 			/* command failed */
1189 			return USB_STOR_TRANSPORT_FAILED;
1190 
1191 		case US_BULK_STAT_PHASE:
1192 			/* phase error -- note that a transport reset will be
1193 			 * invoked by the invoke_transport() function
1194 			 */
1195 			return USB_STOR_TRANSPORT_ERROR;
1196 	}
1197 
1198 	/* we should never get here, but if we do, we're in trouble */
1199 	return USB_STOR_TRANSPORT_ERROR;
1200 }
1201 EXPORT_SYMBOL_GPL(usb_stor_Bulk_transport);
1202 
1203 /***********************************************************************
1204  * Reset routines
1205  ***********************************************************************/
1206 
1207 /* This is the common part of the device reset code.
1208  *
1209  * It's handy that every transport mechanism uses the control endpoint for
1210  * resets.
1211  *
1212  * Basically, we send a reset with a 5-second timeout, so we don't get
1213  * jammed attempting to do the reset.
1214  */
1215 static int usb_stor_reset_common(struct us_data *us,
1216 		u8 request, u8 requesttype,
1217 		u16 value, u16 index, void *data, u16 size)
1218 {
1219 	int result;
1220 	int result2;
1221 
1222 	if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1223 		US_DEBUGP("No reset during disconnect\n");
1224 		return -EIO;
1225 	}
1226 
1227 	result = usb_stor_control_msg(us, us->send_ctrl_pipe,
1228 			request, requesttype, value, index, data, size,
1229 			5*HZ);
1230 	if (result < 0) {
1231 		US_DEBUGP("Soft reset failed: %d\n", result);
1232 		return result;
1233 	}
1234 
1235 	/* Give the device some time to recover from the reset,
1236 	 * but don't delay disconnect processing. */
1237 	wait_event_interruptible_timeout(us->delay_wait,
1238 			test_bit(US_FLIDX_DISCONNECTING, &us->dflags),
1239 			HZ*6);
1240 	if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1241 		US_DEBUGP("Reset interrupted by disconnect\n");
1242 		return -EIO;
1243 	}
1244 
1245 	US_DEBUGP("Soft reset: clearing bulk-in endpoint halt\n");
1246 	result = usb_stor_clear_halt(us, us->recv_bulk_pipe);
1247 
1248 	US_DEBUGP("Soft reset: clearing bulk-out endpoint halt\n");
1249 	result2 = usb_stor_clear_halt(us, us->send_bulk_pipe);
1250 
1251 	/* return a result code based on the result of the clear-halts */
1252 	if (result >= 0)
1253 		result = result2;
1254 	if (result < 0)
1255 		US_DEBUGP("Soft reset failed\n");
1256 	else
1257 		US_DEBUGP("Soft reset done\n");
1258 	return result;
1259 }
1260 
1261 /* This issues a CB[I] Reset to the device in question
1262  */
1263 #define CB_RESET_CMD_SIZE	12
1264 
1265 int usb_stor_CB_reset(struct us_data *us)
1266 {
1267 	US_DEBUGP("%s called\n", __func__);
1268 
1269 	memset(us->iobuf, 0xFF, CB_RESET_CMD_SIZE);
1270 	us->iobuf[0] = SEND_DIAGNOSTIC;
1271 	us->iobuf[1] = 4;
1272 	return usb_stor_reset_common(us, US_CBI_ADSC,
1273 				 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1274 				 0, us->ifnum, us->iobuf, CB_RESET_CMD_SIZE);
1275 }
1276 EXPORT_SYMBOL_GPL(usb_stor_CB_reset);
1277 
1278 /* This issues a Bulk-only Reset to the device in question, including
1279  * clearing the subsequent endpoint halts that may occur.
1280  */
1281 int usb_stor_Bulk_reset(struct us_data *us)
1282 {
1283 	US_DEBUGP("%s called\n", __func__);
1284 
1285 	return usb_stor_reset_common(us, US_BULK_RESET_REQUEST,
1286 				 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1287 				 0, us->ifnum, NULL, 0);
1288 }
1289 EXPORT_SYMBOL_GPL(usb_stor_Bulk_reset);
1290 
1291 /* Issue a USB port reset to the device.  The caller must not hold
1292  * us->dev_mutex.
1293  */
1294 int usb_stor_port_reset(struct us_data *us)
1295 {
1296 	int result;
1297 
1298 	/*for these devices we must use the class specific method */
1299 	if (us->pusb_dev->quirks & USB_QUIRK_RESET_MORPHS)
1300 		return -EPERM;
1301 
1302 	result = usb_lock_device_for_reset(us->pusb_dev, us->pusb_intf);
1303 	if (result < 0)
1304 		US_DEBUGP("unable to lock device for reset: %d\n", result);
1305 	else {
1306 		/* Were we disconnected while waiting for the lock? */
1307 		if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1308 			result = -EIO;
1309 			US_DEBUGP("No reset during disconnect\n");
1310 		} else {
1311 			result = usb_reset_device(us->pusb_dev);
1312 			US_DEBUGP("usb_reset_device returns %d\n",
1313 					result);
1314 		}
1315 		usb_unlock_device(us->pusb_dev);
1316 	}
1317 	return result;
1318 }
1319