1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Driver for USB Mass Storage compliant devices
   4 *
   5 * Current development and maintenance by:
   6 *   (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
   7 *
   8 * Developed with the assistance of:
   9 *   (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
  10 *   (c) 2000 Stephen J. Gowdy (SGowdy@lbl.gov)
  11 *   (c) 2002 Alan Stern <stern@rowland.org>
  12 *
  13 * Initial work by:
  14 *   (c) 1999 Michael Gee (michael@linuxspecific.com)
  15 *
  16 * This driver is based on the 'USB Mass Storage Class' document. This
  17 * describes in detail the protocol used to communicate with such
  18 * devices.  Clearly, the designers had SCSI and ATAPI commands in
  19 * mind when they created this document.  The commands are all very
  20 * similar to commands in the SCSI-II and ATAPI specifications.
  21 *
  22 * It is important to note that in a number of cases this class
  23 * exhibits class-specific exemptions from the USB specification.
  24 * Notably the usage of NAK, STALL and ACK differs from the norm, in
  25 * that they are used to communicate wait, failed and OK on commands.
  26 *
  27 * Also, for certain devices, the interrupt endpoint is used to convey
  28 * status of a command.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  29 */
  30
  31#include <linux/sched.h>
  32#include <linux/gfp.h>
  33#include <linux/errno.h>
  34#include <linux/export.h>
  35
  36#include <linux/usb/quirks.h>
  37
  38#include <scsi/scsi.h>
  39#include <scsi/scsi_eh.h>
  40#include <scsi/scsi_device.h>
  41
  42#include "usb.h"
  43#include "transport.h"
  44#include "protocol.h"
  45#include "scsiglue.h"
  46#include "debug.h"
  47
  48#include <linux/blkdev.h>
  49#include "../../scsi/sd.h"
  50
  51
  52/***********************************************************************
  53 * Data transfer routines
  54 ***********************************************************************/
  55
  56/*
  57 * This is subtle, so pay attention:
  58 * ---------------------------------
  59 * We're very concerned about races with a command abort.  Hanging this code
  60 * is a sure fire way to hang the kernel.  (Note that this discussion applies
  61 * only to transactions resulting from a scsi queued-command, since only
  62 * these transactions are subject to a scsi abort.  Other transactions, such
  63 * as those occurring during device-specific initialization, must be handled
  64 * by a separate code path.)
  65 *
  66 * The abort function (usb_storage_command_abort() in scsiglue.c) first
  67 * sets the machine state and the ABORTING bit in us->dflags to prevent
  68 * new URBs from being submitted.  It then calls usb_stor_stop_transport()
  69 * below, which atomically tests-and-clears the URB_ACTIVE bit in us->dflags
  70 * to see if the current_urb needs to be stopped.  Likewise, the SG_ACTIVE
  71 * bit is tested to see if the current_sg scatter-gather request needs to be
  72 * stopped.  The timeout callback routine does much the same thing.
  73 *
  74 * When a disconnect occurs, the DISCONNECTING bit in us->dflags is set to
  75 * prevent new URBs from being submitted, and usb_stor_stop_transport() is
  76 * called to stop any ongoing requests.
  77 *
  78 * The submit function first verifies that the submitting is allowed
  79 * (neither ABORTING nor DISCONNECTING bits are set) and that the submit
  80 * completes without errors, and only then sets the URB_ACTIVE bit.  This
  81 * prevents the stop_transport() function from trying to cancel the URB
  82 * while the submit call is underway.  Next, the submit function must test
  83 * the flags to see if an abort or disconnect occurred during the submission
  84 * or before the URB_ACTIVE bit was set.  If so, it's essential to cancel
  85 * the URB if it hasn't been cancelled already (i.e., if the URB_ACTIVE bit
  86 * is still set).  Either way, the function must then wait for the URB to
  87 * finish.  Note that the URB can still be in progress even after a call to
  88 * usb_unlink_urb() returns.
  89 *
  90 * The idea is that (1) once the ABORTING or DISCONNECTING bit is set,
  91 * either the stop_transport() function or the submitting function
  92 * is guaranteed to call usb_unlink_urb() for an active URB,
  93 * and (2) test_and_clear_bit() prevents usb_unlink_urb() from being
  94 * called more than once or from being called during usb_submit_urb().
  95 */
  96
  97/*
  98 * This is the completion handler which will wake us up when an URB
  99 * completes.
 100 */
 101static void usb_stor_blocking_completion(struct urb *urb)
 102{
 103	struct completion *urb_done_ptr = urb->context;
 104
 105	complete(urb_done_ptr);
 106}
 107
 108/*
 109 * This is the common part of the URB message submission code
 110 *
 111 * All URBs from the usb-storage driver involved in handling a queued scsi
 112 * command _must_ pass through this function (or something like it) for the
 113 * abort mechanisms to work properly.
 114 */
 115static int usb_stor_msg_common(struct us_data *us, int timeout)
 116{
 117	struct completion urb_done;
 118	long timeleft;
 119	int status;
 120
 121	/* don't submit URBs during abort processing */
 122	if (test_bit(US_FLIDX_ABORTING, &us->dflags))
 123		return -EIO;
 124
 125	/* set up data structures for the wakeup system */
 126	init_completion(&urb_done);
 127
 128	/* fill the common fields in the URB */
 129	us->current_urb->context = &urb_done;
 130	us->current_urb->transfer_flags = 0;
 131
 132	/*
 133	 * we assume that if transfer_buffer isn't us->iobuf then it
 134	 * hasn't been mapped for DMA.  Yes, this is clunky, but it's
 135	 * easier than always having the caller tell us whether the
 136	 * transfer buffer has already been mapped.
 137	 */
 138	if (us->current_urb->transfer_buffer == us->iobuf)
 139		us->current_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 140	us->current_urb->transfer_dma = us->iobuf_dma;
 141
 142	/* submit the URB */
 143	status = usb_submit_urb(us->current_urb, GFP_NOIO);
 144	if (status) {
 145		/* something went wrong */
 146		return status;
 147	}
 148
 149	/*
 150	 * since the URB has been submitted successfully, it's now okay
 151	 * to cancel it
 152	 */
 153	set_bit(US_FLIDX_URB_ACTIVE, &us->dflags);
 154
 155	/* did an abort occur during the submission? */
 156	if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
 157
 158		/* cancel the URB, if it hasn't been cancelled already */
 159		if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
 160			usb_stor_dbg(us, "-- cancelling URB\n");
 161			usb_unlink_urb(us->current_urb);
 162		}
 163	}
 164 
 165	/* wait for the completion of the URB */
 166	timeleft = wait_for_completion_interruptible_timeout(
 167			&urb_done, timeout ? : MAX_SCHEDULE_TIMEOUT);
 168 
 169	clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags);
 170
 171	if (timeleft <= 0) {
 172		usb_stor_dbg(us, "%s -- cancelling URB\n",
 173			     timeleft == 0 ? "Timeout" : "Signal");
 174		usb_kill_urb(us->current_urb);
 175	}
 176
 177	/* return the URB status */
 178	return us->current_urb->status;
 179}
 180
 181/*
 182 * Transfer one control message, with timeouts, and allowing early
 183 * termination.  Return codes are usual -Exxx, *not* USB_STOR_XFER_xxx.
 184 */
 185int usb_stor_control_msg(struct us_data *us, unsigned int pipe,
 186		 u8 request, u8 requesttype, u16 value, u16 index, 
 187		 void *data, u16 size, int timeout)
 188{
 189	int status;
 190
 191	usb_stor_dbg(us, "rq=%02x rqtype=%02x value=%04x index=%02x len=%u\n",
 192		     request, requesttype, value, index, size);
 193
 194	/* fill in the devrequest structure */
 195	us->cr->bRequestType = requesttype;
 196	us->cr->bRequest = request;
 197	us->cr->wValue = cpu_to_le16(value);
 198	us->cr->wIndex = cpu_to_le16(index);
 199	us->cr->wLength = cpu_to_le16(size);
 200
 201	/* fill and submit the URB */
 202	usb_fill_control_urb(us->current_urb, us->pusb_dev, pipe, 
 203			 (unsigned char*) us->cr, data, size, 
 204			 usb_stor_blocking_completion, NULL);
 205	status = usb_stor_msg_common(us, timeout);
 206
 207	/* return the actual length of the data transferred if no error */
 208	if (status == 0)
 209		status = us->current_urb->actual_length;
 210	return status;
 211}
 212EXPORT_SYMBOL_GPL(usb_stor_control_msg);
 213
 214/*
 215 * This is a version of usb_clear_halt() that allows early termination and
 216 * doesn't read the status from the device -- this is because some devices
 217 * crash their internal firmware when the status is requested after a halt.
 218 *
 219 * A definitive list of these 'bad' devices is too difficult to maintain or
 220 * make complete enough to be useful.  This problem was first observed on the
 221 * Hagiwara FlashGate DUAL unit.  However, bus traces reveal that neither
 222 * MacOS nor Windows checks the status after clearing a halt.
 223 *
 224 * Since many vendors in this space limit their testing to interoperability
 225 * with these two OSes, specification violations like this one are common.
 226 */
 227int usb_stor_clear_halt(struct us_data *us, unsigned int pipe)
 228{
 229	int result;
 230	int endp = usb_pipeendpoint(pipe);
 231
 232	if (usb_pipein (pipe))
 233		endp |= USB_DIR_IN;
 234
 235	result = usb_stor_control_msg(us, us->send_ctrl_pipe,
 236		USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT,
 237		USB_ENDPOINT_HALT, endp,
 238		NULL, 0, 3*HZ);
 239
 240	if (result >= 0)
 241		usb_reset_endpoint(us->pusb_dev, endp);
 242
 243	usb_stor_dbg(us, "result = %d\n", result);
 244	return result;
 245}
 246EXPORT_SYMBOL_GPL(usb_stor_clear_halt);
 247
 248
 249/*
 250 * Interpret the results of a URB transfer
 251 *
 252 * This function prints appropriate debugging messages, clears halts on
 253 * non-control endpoints, and translates the status to the corresponding
 254 * USB_STOR_XFER_xxx return code.
 255 */
 256static int interpret_urb_result(struct us_data *us, unsigned int pipe,
 257		unsigned int length, int result, unsigned int partial)
 258{
 259	usb_stor_dbg(us, "Status code %d; transferred %u/%u\n",
 260		     result, partial, length);
 261	switch (result) {
 262
 263	/* no error code; did we send all the data? */
 264	case 0:
 265		if (partial != length) {
 266			usb_stor_dbg(us, "-- short transfer\n");
 267			return USB_STOR_XFER_SHORT;
 268		}
 269
 270		usb_stor_dbg(us, "-- transfer complete\n");
 271		return USB_STOR_XFER_GOOD;
 272
 273	/* stalled */
 274	case -EPIPE:
 275		/*
 276		 * for control endpoints, (used by CB[I]) a stall indicates
 277		 * a failed command
 278		 */
 279		if (usb_pipecontrol(pipe)) {
 280			usb_stor_dbg(us, "-- stall on control pipe\n");
 281			return USB_STOR_XFER_STALLED;
 282		}
 283
 284		/* for other sorts of endpoint, clear the stall */
 285		usb_stor_dbg(us, "clearing endpoint halt for pipe 0x%x\n",
 286			     pipe);
 287		if (usb_stor_clear_halt(us, pipe) < 0)
 288			return USB_STOR_XFER_ERROR;
 289		return USB_STOR_XFER_STALLED;
 290
 291	/* babble - the device tried to send more than we wanted to read */
 292	case -EOVERFLOW:
 293		usb_stor_dbg(us, "-- babble\n");
 294		return USB_STOR_XFER_LONG;
 295
 296	/* the transfer was cancelled by abort, disconnect, or timeout */
 297	case -ECONNRESET:
 298		usb_stor_dbg(us, "-- transfer cancelled\n");
 299		return USB_STOR_XFER_ERROR;
 300
 301	/* short scatter-gather read transfer */
 302	case -EREMOTEIO:
 303		usb_stor_dbg(us, "-- short read transfer\n");
 304		return USB_STOR_XFER_SHORT;
 305
 306	/* abort or disconnect in progress */
 307	case -EIO:
 308		usb_stor_dbg(us, "-- abort or disconnect in progress\n");
 309		return USB_STOR_XFER_ERROR;
 310
 311	/* the catch-all error case */
 312	default:
 313		usb_stor_dbg(us, "-- unknown error\n");
 314		return USB_STOR_XFER_ERROR;
 315	}
 316}
 317
 318/*
 319 * Transfer one control message, without timeouts, but allowing early
 320 * termination.  Return codes are USB_STOR_XFER_xxx.
 321 */
 322int usb_stor_ctrl_transfer(struct us_data *us, unsigned int pipe,
 323		u8 request, u8 requesttype, u16 value, u16 index,
 324		void *data, u16 size)
 325{
 326	int result;
 327
 328	usb_stor_dbg(us, "rq=%02x rqtype=%02x value=%04x index=%02x len=%u\n",
 329		     request, requesttype, value, index, size);
 330
 331	/* fill in the devrequest structure */
 332	us->cr->bRequestType = requesttype;
 333	us->cr->bRequest = request;
 334	us->cr->wValue = cpu_to_le16(value);
 335	us->cr->wIndex = cpu_to_le16(index);
 336	us->cr->wLength = cpu_to_le16(size);
 337
 338	/* fill and submit the URB */
 339	usb_fill_control_urb(us->current_urb, us->pusb_dev, pipe, 
 340			 (unsigned char*) us->cr, data, size, 
 341			 usb_stor_blocking_completion, NULL);
 342	result = usb_stor_msg_common(us, 0);
 343
 344	return interpret_urb_result(us, pipe, size, result,
 345			us->current_urb->actual_length);
 346}
 347EXPORT_SYMBOL_GPL(usb_stor_ctrl_transfer);
 348
 349/*
 350 * Receive one interrupt buffer, without timeouts, but allowing early
 351 * termination.  Return codes are USB_STOR_XFER_xxx.
 352 *
 353 * This routine always uses us->recv_intr_pipe as the pipe and
 354 * us->ep_bInterval as the interrupt interval.
 355 */
 356static int usb_stor_intr_transfer(struct us_data *us, void *buf,
 357				  unsigned int length)
 358{
 359	int result;
 360	unsigned int pipe = us->recv_intr_pipe;
 361	unsigned int maxp;
 362
 363	usb_stor_dbg(us, "xfer %u bytes\n", length);
 364
 365	/* calculate the max packet size */
 366	maxp = usb_maxpacket(us->pusb_dev, pipe);
 367	if (maxp > length)
 368		maxp = length;
 369
 370	/* fill and submit the URB */
 371	usb_fill_int_urb(us->current_urb, us->pusb_dev, pipe, buf,
 372			maxp, usb_stor_blocking_completion, NULL,
 373			us->ep_bInterval);
 374	result = usb_stor_msg_common(us, 0);
 375
 376	return interpret_urb_result(us, pipe, length, result,
 377			us->current_urb->actual_length);
 378}
 379
 380/*
 381 * Transfer one buffer via bulk pipe, without timeouts, but allowing early
 382 * termination.  Return codes are USB_STOR_XFER_xxx.  If the bulk pipe
 383 * stalls during the transfer, the halt is automatically cleared.
 384 */
 385int usb_stor_bulk_transfer_buf(struct us_data *us, unsigned int pipe,
 386	void *buf, unsigned int length, unsigned int *act_len)
 387{
 388	int result;
 389
 390	usb_stor_dbg(us, "xfer %u bytes\n", length);
 391
 392	/* fill and submit the URB */
 393	usb_fill_bulk_urb(us->current_urb, us->pusb_dev, pipe, buf, length,
 394		      usb_stor_blocking_completion, NULL);
 395	result = usb_stor_msg_common(us, 0);
 396
 397	/* store the actual length of the data transferred */
 398	if (act_len)
 399		*act_len = us->current_urb->actual_length;
 400	return interpret_urb_result(us, pipe, length, result, 
 401			us->current_urb->actual_length);
 402}
 403EXPORT_SYMBOL_GPL(usb_stor_bulk_transfer_buf);
 404
 405/*
 406 * Transfer a scatter-gather list via bulk transfer
 407 *
 408 * This function does basically the same thing as usb_stor_bulk_transfer_buf()
 409 * above, but it uses the usbcore scatter-gather library.
 410 */
 411static int usb_stor_bulk_transfer_sglist(struct us_data *us, unsigned int pipe,
 412		struct scatterlist *sg, int num_sg, unsigned int length,
 413		unsigned int *act_len)
 414{
 415	int result;
 416
 417	/* don't submit s-g requests during abort processing */
 418	if (test_bit(US_FLIDX_ABORTING, &us->dflags))
 419		goto usb_stor_xfer_error;
 420
 421	/* initialize the scatter-gather request block */
 422	usb_stor_dbg(us, "xfer %u bytes, %d entries\n", length, num_sg);
 423	result = usb_sg_init(&us->current_sg, us->pusb_dev, pipe, 0,
 424			sg, num_sg, length, GFP_NOIO);
 425	if (result) {
 426		usb_stor_dbg(us, "usb_sg_init returned %d\n", result);
 427		goto usb_stor_xfer_error;
 428	}
 429
 430	/*
 431	 * since the block has been initialized successfully, it's now
 432	 * okay to cancel it
 433	 */
 434	set_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
 435
 436	/* did an abort occur during the submission? */
 437	if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
 438
 439		/* cancel the request, if it hasn't been cancelled already */
 440		if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
 441			usb_stor_dbg(us, "-- cancelling sg request\n");
 442			usb_sg_cancel(&us->current_sg);
 443		}
 444	}
 445
 446	/* wait for the completion of the transfer */
 447	usb_sg_wait(&us->current_sg);
 448	clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
 449
 450	result = us->current_sg.status;
 451	if (act_len)
 452		*act_len = us->current_sg.bytes;
 453	return interpret_urb_result(us, pipe, length, result,
 454			us->current_sg.bytes);
 455
 456usb_stor_xfer_error:
 457	if (act_len)
 458		*act_len = 0;
 459	return USB_STOR_XFER_ERROR;
 460}
 461
 462/*
 463 * Common used function. Transfer a complete command
 464 * via usb_stor_bulk_transfer_sglist() above. Set cmnd resid
 465 */
 466int 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}
 477EXPORT_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 */
 488int 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}
 513EXPORT_SYMBOL_GPL(usb_stor_bulk_transfer_sg);
 514
 515/***********************************************************************
 516 * Transport routines
 517 ***********************************************************************/
 518
 519/*
 520 * There are so many devices that report the capacity incorrectly,
 521 * this routine was written to counteract some of the resulting
 522 * problems.
 523 */
 524static void last_sector_hacks(struct us_data *us, struct scsi_cmnd *srb)
 525{
 526	struct gendisk *disk;
 527	struct scsi_disk *sdkp;
 528	u32 sector;
 529
 530	/* To Report "Medium Error: Record Not Found */
 531	static unsigned char record_not_found[18] = {
 532		[0]	= 0x70,			/* current error */
 533		[2]	= MEDIUM_ERROR,		/* = 0x03 */
 534		[7]	= 0x0a,			/* additional length */
 535		[12]	= 0x14			/* Record Not Found */
 536	};
 537
 538	/*
 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 = scsi_cmd_to_rq(srb)->q->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		/*
 566		 * The command succeeded.  We know this device doesn't
 567		 * have the last-sector bug, so stop checking it.
 568		 */
 569		us->use_last_sector_hacks = 0;
 570
 571	} else {
 572		/*
 573		 * The command failed.  Allow up to 3 retries in case this
 574		 * is some normal sort of failure.  After that, assume the
 575		 * capacity is wrong and we're trying to access the sector
 576		 * beyond the end.  Replace the result code and sense data
 577		 * with values that will cause the SCSI core to fail the
 578		 * command immediately, instead of going into an infinite
 579		 * (or even just a very long) retry loop.
 580		 */
 581		if (++us->last_sector_retries < 3)
 582			return;
 583		srb->result = SAM_STAT_CHECK_CONDITION;
 584		memcpy(srb->sense_buffer, record_not_found,
 585				sizeof(record_not_found));
 586	}
 587
 588 done:
 589	/*
 590	 * Don't reset the retry counter for TEST UNIT READY commands,
 591	 * because they get issued after device resets which might be
 592	 * caused by a failed last-sector access.
 593	 */
 594	if (srb->cmnd[0] != TEST_UNIT_READY)
 595		us->last_sector_retries = 0;
 596}
 597
 598/*
 599 * Invoke the transport and basic error-handling/recovery methods
 600 *
 601 * This is used by the protocol layers to actually send the message to
 602 * the device and receive the response.
 603 */
 604void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
 605{
 606	int need_auto_sense;
 607	int result;
 608
 609	/* send the command to the transport layer */
 610	scsi_set_resid(srb, 0);
 611	result = us->transport(srb, us);
 612
 613	/*
 614	 * if the command gets aborted by the higher layers, we need to
 615	 * short-circuit all other processing
 616	 */
 617	if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
 618		usb_stor_dbg(us, "-- command was aborted\n");
 619		srb->result = DID_ABORT << 16;
 620		goto Handle_Errors;
 621	}
 622
 623	/* if there is a transport error, reset and don't auto-sense */
 624	if (result == USB_STOR_TRANSPORT_ERROR) {
 625		usb_stor_dbg(us, "-- transport indicates error, resetting\n");
 626		srb->result = DID_ERROR << 16;
 627		goto Handle_Errors;
 628	}
 629
 630	/* if the transport provided its own sense data, don't auto-sense */
 631	if (result == USB_STOR_TRANSPORT_NO_SENSE) {
 632		srb->result = SAM_STAT_CHECK_CONDITION;
 633		last_sector_hacks(us, srb);
 634		return;
 635	}
 636
 637	srb->result = SAM_STAT_GOOD;
 638
 639	/*
 640	 * Determine if we need to auto-sense
 641	 *
 642	 * I normally don't use a flag like this, but it's almost impossible
 643	 * to understand what's going on here if I don't.
 644	 */
 645	need_auto_sense = 0;
 646
 647	/*
 648	 * If we're running the CB transport, which is incapable
 649	 * of determining status on its own, we will auto-sense
 650	 * unless the operation involved a data-in transfer.  Devices
 651	 * can signal most data-in errors by stalling the bulk-in pipe.
 652	 */
 653	if ((us->protocol == USB_PR_CB || us->protocol == USB_PR_DPCM_USB) &&
 654			srb->sc_data_direction != DMA_FROM_DEVICE) {
 655		usb_stor_dbg(us, "-- CB transport device requiring auto-sense\n");
 656		need_auto_sense = 1;
 657	}
 658
 659	/* Some devices (Kindle) require another command after SYNC CACHE */
 660	if ((us->fflags & US_FL_SENSE_AFTER_SYNC) &&
 661			srb->cmnd[0] == SYNCHRONIZE_CACHE) {
 662		usb_stor_dbg(us, "-- sense after SYNC CACHE\n");
 663		need_auto_sense = 1;
 664	}
 665
 666	/*
 667	 * If we have a failure, we're going to do a REQUEST_SENSE 
 668	 * automatically.  Note that we differentiate between a command
 669	 * "failure" and an "error" in the transport mechanism.
 670	 */
 671	if (result == USB_STOR_TRANSPORT_FAILED) {
 672		usb_stor_dbg(us, "-- transport indicates command failure\n");
 673		need_auto_sense = 1;
 674	}
 675
 676	/*
 677	 * Determine if this device is SAT by seeing if the
 678	 * command executed successfully.  Otherwise we'll have
 679	 * to wait for at least one CHECK_CONDITION to determine
 680	 * SANE_SENSE support
 681	 */
 682	if (unlikely((srb->cmnd[0] == ATA_16 || srb->cmnd[0] == ATA_12) &&
 683	    result == USB_STOR_TRANSPORT_GOOD &&
 684	    !(us->fflags & US_FL_SANE_SENSE) &&
 685	    !(us->fflags & US_FL_BAD_SENSE) &&
 686	    !(srb->cmnd[2] & 0x20))) {
 687		usb_stor_dbg(us, "-- SAT supported, increasing auto-sense\n");
 688		us->fflags |= US_FL_SANE_SENSE;
 689	}
 690
 691	/*
 692	 * A short transfer on a command where we don't expect it
 693	 * is unusual, but it doesn't mean we need to auto-sense.
 694	 */
 695	if ((scsi_get_resid(srb) > 0) &&
 696	    !((srb->cmnd[0] == REQUEST_SENSE) ||
 697	      (srb->cmnd[0] == INQUIRY) ||
 698	      (srb->cmnd[0] == MODE_SENSE) ||
 699	      (srb->cmnd[0] == LOG_SENSE) ||
 700	      (srb->cmnd[0] == MODE_SENSE_10))) {
 701		usb_stor_dbg(us, "-- unexpectedly short transfer\n");
 702	}
 703
 704	/* Now, if we need to do the auto-sense, let's do it */
 705	if (need_auto_sense) {
 706		int temp_result;
 707		struct scsi_eh_save ses;
 708		int sense_size = US_SENSE_SIZE;
 709		struct scsi_sense_hdr sshdr;
 710		const u8 *scdd;
 711		u8 fm_ili;
 712
 713		/* device supports and needs bigger sense buffer */
 714		if (us->fflags & US_FL_SANE_SENSE)
 715			sense_size = ~0;
 716Retry_Sense:
 717		usb_stor_dbg(us, "Issuing auto-REQUEST_SENSE\n");
 718
 719		scsi_eh_prep_cmnd(srb, &ses, NULL, 0, sense_size);
 720
 721		/* FIXME: we must do the protocol translation here */
 722		if (us->subclass == USB_SC_RBC || us->subclass == USB_SC_SCSI ||
 723				us->subclass == USB_SC_CYP_ATACB)
 724			srb->cmd_len = 6;
 725		else
 726			srb->cmd_len = 12;
 727
 728		/* issue the auto-sense command */
 729		scsi_set_resid(srb, 0);
 730		temp_result = us->transport(us->srb, us);
 731
 732		/* let's clean up right away */
 733		scsi_eh_restore_cmnd(srb, &ses);
 734
 735		if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
 736			usb_stor_dbg(us, "-- auto-sense aborted\n");
 737			srb->result = DID_ABORT << 16;
 738
 739			/* If SANE_SENSE caused this problem, disable it */
 740			if (sense_size != US_SENSE_SIZE) {
 741				us->fflags &= ~US_FL_SANE_SENSE;
 742				us->fflags |= US_FL_BAD_SENSE;
 743			}
 744			goto Handle_Errors;
 745		}
 746
 747		/*
 748		 * Some devices claim to support larger sense but fail when
 749		 * trying to request it. When a transport failure happens
 750		 * using US_FS_SANE_SENSE, we always retry with a standard
 751		 * (small) sense request. This fixes some USB GSM modems
 752		 */
 753		if (temp_result == USB_STOR_TRANSPORT_FAILED &&
 754				sense_size != US_SENSE_SIZE) {
 755			usb_stor_dbg(us, "-- auto-sense failure, retry small sense\n");
 756			sense_size = US_SENSE_SIZE;
 757			us->fflags &= ~US_FL_SANE_SENSE;
 758			us->fflags |= US_FL_BAD_SENSE;
 759			goto Retry_Sense;
 760		}
 761
 762		/* Other failures */
 763		if (temp_result != USB_STOR_TRANSPORT_GOOD) {
 764			usb_stor_dbg(us, "-- auto-sense failure\n");
 765
 766			/*
 767			 * we skip the reset if this happens to be a
 768			 * multi-target device, since failure of an
 769			 * auto-sense is perfectly valid
 770			 */
 771			srb->result = DID_ERROR << 16;
 772			if (!(us->fflags & US_FL_SCM_MULT_TARG))
 773				goto Handle_Errors;
 774			return;
 775		}
 776
 777		/*
 778		 * If the sense data returned is larger than 18-bytes then we
 779		 * assume this device supports requesting more in the future.
 780		 * The response code must be 70h through 73h inclusive.
 781		 */
 782		if (srb->sense_buffer[7] > (US_SENSE_SIZE - 8) &&
 783		    !(us->fflags & US_FL_SANE_SENSE) &&
 784		    !(us->fflags & US_FL_BAD_SENSE) &&
 785		    (srb->sense_buffer[0] & 0x7C) == 0x70) {
 786			usb_stor_dbg(us, "-- SANE_SENSE support enabled\n");
 787			us->fflags |= US_FL_SANE_SENSE;
 788
 789			/*
 790			 * Indicate to the user that we truncated their sense
 791			 * because we didn't know it supported larger sense.
 792			 */
 793			usb_stor_dbg(us, "-- Sense data truncated to %i from %i\n",
 794				     US_SENSE_SIZE,
 795				     srb->sense_buffer[7] + 8);
 796			srb->sense_buffer[7] = (US_SENSE_SIZE - 8);
 797		}
 798
 799		scsi_normalize_sense(srb->sense_buffer, SCSI_SENSE_BUFFERSIZE,
 800				     &sshdr);
 801
 802		usb_stor_dbg(us, "-- Result from auto-sense is %d\n",
 803			     temp_result);
 804		usb_stor_dbg(us, "-- code: 0x%x, key: 0x%x, ASC: 0x%x, ASCQ: 0x%x\n",
 805			     sshdr.response_code, sshdr.sense_key,
 806			     sshdr.asc, sshdr.ascq);
 807#ifdef CONFIG_USB_STORAGE_DEBUG
 808		usb_stor_show_sense(us, sshdr.sense_key, sshdr.asc, sshdr.ascq);
 809#endif
 810
 811		/* set the result so the higher layers expect this data */
 812		srb->result = SAM_STAT_CHECK_CONDITION;
 813
 814		scdd = scsi_sense_desc_find(srb->sense_buffer,
 815					    SCSI_SENSE_BUFFERSIZE, 4);
 816		fm_ili = (scdd ? scdd[3] : srb->sense_buffer[2]) & 0xA0;
 817
 818		/*
 819		 * We often get empty sense data.  This could indicate that
 820		 * everything worked or that there was an unspecified
 821		 * problem.  We have to decide which.
 822		 */
 823		if (sshdr.sense_key == 0 && sshdr.asc == 0 && sshdr.ascq == 0 &&
 824		    fm_ili == 0) {
 825			/*
 826			 * If things are really okay, then let's show that.
 827			 * Zero out the sense buffer so the higher layers
 828			 * won't realize we did an unsolicited auto-sense.
 829			 */
 830			if (result == USB_STOR_TRANSPORT_GOOD) {
 831				srb->result = SAM_STAT_GOOD;
 832				srb->sense_buffer[0] = 0x0;
 833			}
 834
 835			/*
 836			 * ATA-passthru commands use sense data to report
 837			 * the command completion status, and often devices
 838			 * return Check Condition status when nothing is
 839			 * wrong.
 840			 */
 841			else if (srb->cmnd[0] == ATA_16 ||
 842					srb->cmnd[0] == ATA_12) {
 843				/* leave the data alone */
 844			}
 845
 846			/*
 847			 * If there was a problem, report an unspecified
 848			 * hardware error to prevent the higher layers from
 849			 * entering an infinite retry loop.
 850			 */
 851			else {
 852				srb->result = DID_ERROR << 16;
 853				if ((sshdr.response_code & 0x72) == 0x72)
 854					srb->sense_buffer[1] = HARDWARE_ERROR;
 855				else
 856					srb->sense_buffer[2] = HARDWARE_ERROR;
 857			}
 858		}
 859	}
 860
 861	/*
 862	 * Some devices don't work or return incorrect data the first
 863	 * time they get a READ(10) command, or for the first READ(10)
 864	 * after a media change.  If the INITIAL_READ10 flag is set,
 865	 * keep track of whether READ(10) commands succeed.  If the
 866	 * previous one succeeded and this one failed, set the REDO_READ10
 867	 * flag to force a retry.
 868	 */
 869	if (unlikely((us->fflags & US_FL_INITIAL_READ10) &&
 870			srb->cmnd[0] == READ_10)) {
 871		if (srb->result == SAM_STAT_GOOD) {
 872			set_bit(US_FLIDX_READ10_WORKED, &us->dflags);
 873		} else if (test_bit(US_FLIDX_READ10_WORKED, &us->dflags)) {
 874			clear_bit(US_FLIDX_READ10_WORKED, &us->dflags);
 875			set_bit(US_FLIDX_REDO_READ10, &us->dflags);
 876		}
 877
 878		/*
 879		 * Next, if the REDO_READ10 flag is set, return a result
 880		 * code that will cause the SCSI core to retry the READ(10)
 881		 * command immediately.
 882		 */
 883		if (test_bit(US_FLIDX_REDO_READ10, &us->dflags)) {
 884			clear_bit(US_FLIDX_REDO_READ10, &us->dflags);
 885			srb->result = DID_IMM_RETRY << 16;
 886			srb->sense_buffer[0] = 0;
 887		}
 888	}
 889
 890	/* Did we transfer less than the minimum amount required? */
 891	if ((srb->result == SAM_STAT_GOOD || srb->sense_buffer[2] == 0) &&
 892			scsi_bufflen(srb) - scsi_get_resid(srb) < srb->underflow)
 893		srb->result = DID_ERROR << 16;
 894
 895	last_sector_hacks(us, srb);
 896	return;
 897
 898	/*
 899	 * Error and abort processing: try to resynchronize with the device
 900	 * by issuing a port reset.  If that fails, try a class-specific
 901	 * device reset.
 902	 */
 903  Handle_Errors:
 904
 905	/*
 906	 * Set the RESETTING bit, and clear the ABORTING bit so that
 907	 * the reset may proceed.
 908	 */
 909	scsi_lock(us_to_host(us));
 910	set_bit(US_FLIDX_RESETTING, &us->dflags);
 911	clear_bit(US_FLIDX_ABORTING, &us->dflags);
 912	scsi_unlock(us_to_host(us));
 913
 914	/*
 915	 * We must release the device lock because the pre_reset routine
 916	 * will want to acquire it.
 917	 */
 918	mutex_unlock(&us->dev_mutex);
 919	result = usb_stor_port_reset(us);
 920	mutex_lock(&us->dev_mutex);
 921
 922	if (result < 0) {
 923		scsi_lock(us_to_host(us));
 924		usb_stor_report_device_reset(us);
 925		scsi_unlock(us_to_host(us));
 926		us->transport_reset(us);
 927	}
 928	clear_bit(US_FLIDX_RESETTING, &us->dflags);
 929	last_sector_hacks(us, srb);
 930}
 931
 932/* Stop the current URB transfer */
 933void usb_stor_stop_transport(struct us_data *us)
 934{
 935	/*
 936	 * If the state machine is blocked waiting for an URB,
 937	 * let's wake it up.  The test_and_clear_bit() call
 938	 * guarantees that if a URB has just been submitted,
 939	 * it won't be cancelled more than once.
 940	 */
 941	if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
 942		usb_stor_dbg(us, "-- cancelling URB\n");
 943		usb_unlink_urb(us->current_urb);
 944	}
 945
 946	/* If we are waiting for a scatter-gather operation, cancel it. */
 947	if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
 948		usb_stor_dbg(us, "-- cancelling sg request\n");
 949		usb_sg_cancel(&us->current_sg);
 950	}
 951}
 952
 953/*
 954 * Control/Bulk and Control/Bulk/Interrupt transport
 955 */
 956
 957int usb_stor_CB_transport(struct scsi_cmnd *srb, struct us_data *us)
 958{
 959	unsigned int transfer_length = scsi_bufflen(srb);
 960	unsigned int pipe = 0;
 961	int result;
 962
 963	/* COMMAND STAGE */
 964	/* let's send the command via the control pipe */
 965	/*
 966	 * Command is sometime (f.e. after scsi_eh_prep_cmnd) on the stack.
 967	 * Stack may be vmallocated.  So no DMA for us.  Make a copy.
 968	 */
 969	memcpy(us->iobuf, srb->cmnd, srb->cmd_len);
 970	result = usb_stor_ctrl_transfer(us, us->send_ctrl_pipe,
 971				      US_CBI_ADSC, 
 972				      USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0, 
 973				      us->ifnum, us->iobuf, srb->cmd_len);
 974
 975	/* check the return code for the command */
 976	usb_stor_dbg(us, "Call to usb_stor_ctrl_transfer() returned %d\n",
 977		     result);
 978
 979	/* if we stalled the command, it means command failed */
 980	if (result == USB_STOR_XFER_STALLED) {
 981		return USB_STOR_TRANSPORT_FAILED;
 982	}
 983
 984	/* Uh oh... serious problem here */
 985	if (result != USB_STOR_XFER_GOOD) {
 986		return USB_STOR_TRANSPORT_ERROR;
 987	}
 988
 989	/* DATA STAGE */
 990	/* transfer the data payload for this command, if one exists*/
 991	if (transfer_length) {
 992		pipe = srb->sc_data_direction == DMA_FROM_DEVICE ? 
 993				us->recv_bulk_pipe : us->send_bulk_pipe;
 994		result = usb_stor_bulk_srb(us, pipe, srb);
 995		usb_stor_dbg(us, "CBI data stage result is 0x%x\n", result);
 996
 997		/* if we stalled the data transfer it means command failed */
 998		if (result == USB_STOR_XFER_STALLED)
 999			return USB_STOR_TRANSPORT_FAILED;
1000		if (result > USB_STOR_XFER_STALLED)
1001			return USB_STOR_TRANSPORT_ERROR;
1002	}
1003
1004	/* STATUS STAGE */
1005
1006	/*
1007	 * NOTE: CB does not have a status stage.  Silly, I know.  So
1008	 * we have to catch this at a higher level.
1009	 */
1010	if (us->protocol != USB_PR_CBI)
1011		return USB_STOR_TRANSPORT_GOOD;
1012
1013	result = usb_stor_intr_transfer(us, us->iobuf, 2);
1014	usb_stor_dbg(us, "Got interrupt data (0x%x, 0x%x)\n",
1015		     us->iobuf[0], us->iobuf[1]);
1016	if (result != USB_STOR_XFER_GOOD)
1017		return USB_STOR_TRANSPORT_ERROR;
1018
1019	/*
1020	 * UFI gives us ASC and ASCQ, like a request sense
1021	 *
1022	 * REQUEST_SENSE and INQUIRY don't affect the sense data on UFI
1023	 * devices, so we ignore the information for those commands.  Note
1024	 * that this means we could be ignoring a real error on these
1025	 * commands, but that can't be helped.
1026	 */
1027	if (us->subclass == USB_SC_UFI) {
1028		if (srb->cmnd[0] == REQUEST_SENSE ||
1029		    srb->cmnd[0] == INQUIRY)
1030			return USB_STOR_TRANSPORT_GOOD;
1031		if (us->iobuf[0])
1032			goto Failed;
1033		return USB_STOR_TRANSPORT_GOOD;
1034	}
1035
1036	/*
1037	 * If not UFI, we interpret the data as a result code 
1038	 * The first byte should always be a 0x0.
1039	 *
1040	 * Some bogus devices don't follow that rule.  They stuff the ASC
1041	 * into the first byte -- so if it's non-zero, call it a failure.
1042	 */
1043	if (us->iobuf[0]) {
1044		usb_stor_dbg(us, "CBI IRQ data showed reserved bType 0x%x\n",
1045			     us->iobuf[0]);
1046		goto Failed;
1047
1048	}
1049
1050	/* The second byte & 0x0F should be 0x0 for good, otherwise error */
1051	switch (us->iobuf[1] & 0x0F) {
1052		case 0x00: 
1053			return USB_STOR_TRANSPORT_GOOD;
1054		case 0x01: 
1055			goto Failed;
1056	}
1057	return USB_STOR_TRANSPORT_ERROR;
1058
1059	/*
1060	 * the CBI spec requires that the bulk pipe must be cleared
1061	 * following any data-in/out command failure (section 2.4.3.1.3)
1062	 */
1063  Failed:
1064	if (pipe)
1065		usb_stor_clear_halt(us, pipe);
1066	return USB_STOR_TRANSPORT_FAILED;
1067}
1068EXPORT_SYMBOL_GPL(usb_stor_CB_transport);
1069
1070/*
1071 * Bulk only transport
1072 */
1073
1074/* Determine what the maximum LUN supported is */
1075int usb_stor_Bulk_max_lun(struct us_data *us)
1076{
1077	int result;
1078
1079	/* issue the command */
1080	us->iobuf[0] = 0;
1081	result = usb_stor_control_msg(us, us->recv_ctrl_pipe,
1082				 US_BULK_GET_MAX_LUN, 
1083				 USB_DIR_IN | USB_TYPE_CLASS | 
1084				 USB_RECIP_INTERFACE,
1085				 0, us->ifnum, us->iobuf, 1, 10*HZ);
1086
1087	usb_stor_dbg(us, "GetMaxLUN command result is %d, data is %d\n",
1088		     result, us->iobuf[0]);
1089
1090	/*
1091	 * If we have a successful request, return the result if valid. The
1092	 * CBW LUN field is 4 bits wide, so the value reported by the device
1093	 * should fit into that.
1094	 */
1095	if (result > 0) {
1096		if (us->iobuf[0] < 16) {
1097			return us->iobuf[0];
1098		} else {
1099			dev_info(&us->pusb_intf->dev,
1100				 "Max LUN %d is not valid, using 0 instead",
1101				 us->iobuf[0]);
1102		}
1103	}
1104
1105	/*
1106	 * Some devices don't like GetMaxLUN.  They may STALL the control
1107	 * pipe, they may return a zero-length result, they may do nothing at
1108	 * all and timeout, or they may fail in even more bizarrely creative
1109	 * ways.  In these cases the best approach is to use the default
1110	 * value: only one LUN.
1111	 */
1112	return 0;
1113}
1114
1115int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us)
1116{
1117	struct bulk_cb_wrap *bcb = (struct bulk_cb_wrap *) us->iobuf;
1118	struct bulk_cs_wrap *bcs = (struct bulk_cs_wrap *) us->iobuf;
1119	unsigned int transfer_length = scsi_bufflen(srb);
1120	unsigned int residue;
1121	int result;
1122	int fake_sense = 0;
1123	unsigned int cswlen;
1124	unsigned int cbwlen = US_BULK_CB_WRAP_LEN;
1125
1126	/* Take care of BULK32 devices; set extra byte to 0 */
1127	if (unlikely(us->fflags & US_FL_BULK32)) {
1128		cbwlen = 32;
1129		us->iobuf[31] = 0;
1130	}
1131
1132	/* set up the command wrapper */
1133	bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
1134	bcb->DataTransferLength = cpu_to_le32(transfer_length);
1135	bcb->Flags = srb->sc_data_direction == DMA_FROM_DEVICE ?
1136		US_BULK_FLAG_IN : 0;
1137	bcb->Tag = ++us->tag;
1138	bcb->Lun = srb->device->lun;
1139	if (us->fflags & US_FL_SCM_MULT_TARG)
1140		bcb->Lun |= srb->device->id << 4;
1141	bcb->Length = srb->cmd_len;
1142
1143	/* copy the command payload */
1144	memset(bcb->CDB, 0, sizeof(bcb->CDB));
1145	memcpy(bcb->CDB, srb->cmnd, bcb->Length);
1146
1147	/* send it to out endpoint */
1148	usb_stor_dbg(us, "Bulk Command S 0x%x T 0x%x L %d F %d Trg %d LUN %d CL %d\n",
1149		     le32_to_cpu(bcb->Signature), bcb->Tag,
1150		     le32_to_cpu(bcb->DataTransferLength), bcb->Flags,
1151		     (bcb->Lun >> 4), (bcb->Lun & 0x0F),
1152		     bcb->Length);
1153	result = usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
1154				bcb, cbwlen, NULL);
1155	usb_stor_dbg(us, "Bulk command transfer result=%d\n", result);
1156	if (result != USB_STOR_XFER_GOOD)
1157		return USB_STOR_TRANSPORT_ERROR;
1158
1159	/* DATA STAGE */
1160	/* send/receive data payload, if there is any */
1161
1162	/*
1163	 * Some USB-IDE converter chips need a 100us delay between the
1164	 * command phase and the data phase.  Some devices need a little
1165	 * more than that, probably because of clock rate inaccuracies.
1166	 */
1167	if (unlikely(us->fflags & US_FL_GO_SLOW))
1168		usleep_range(125, 150);
1169
1170	if (transfer_length) {
1171		unsigned int pipe = srb->sc_data_direction == DMA_FROM_DEVICE ? 
1172				us->recv_bulk_pipe : us->send_bulk_pipe;
1173		result = usb_stor_bulk_srb(us, pipe, srb);
1174		usb_stor_dbg(us, "Bulk data transfer result 0x%x\n", result);
1175		if (result == USB_STOR_XFER_ERROR)
1176			return USB_STOR_TRANSPORT_ERROR;
1177
1178		/*
1179		 * If the device tried to send back more data than the
1180		 * amount requested, the spec requires us to transfer
1181		 * the CSW anyway.  Since there's no point retrying
1182		 * the command, we'll return fake sense data indicating
1183		 * Illegal Request, Invalid Field in CDB.
1184		 */
1185		if (result == USB_STOR_XFER_LONG)
1186			fake_sense = 1;
1187
1188		/*
1189		 * Sometimes a device will mistakenly skip the data phase
1190		 * and go directly to the status phase without sending a
1191		 * zero-length packet.  If we get a 13-byte response here,
1192		 * check whether it really is a CSW.
1193		 */
1194		if (result == USB_STOR_XFER_SHORT &&
1195				srb->sc_data_direction == DMA_FROM_DEVICE &&
1196				transfer_length - scsi_get_resid(srb) ==
1197					US_BULK_CS_WRAP_LEN) {
1198			struct scatterlist *sg = NULL;
1199			unsigned int offset = 0;
1200
1201			if (usb_stor_access_xfer_buf((unsigned char *) bcs,
1202					US_BULK_CS_WRAP_LEN, srb, &sg,
1203					&offset, FROM_XFER_BUF) ==
1204						US_BULK_CS_WRAP_LEN &&
1205					bcs->Signature ==
1206						cpu_to_le32(US_BULK_CS_SIGN)) {
1207				usb_stor_dbg(us, "Device skipped data phase\n");
1208				scsi_set_resid(srb, transfer_length);
1209				goto skipped_data_phase;
1210			}
1211		}
1212	}
1213
1214	/*
1215	 * See flow chart on pg 15 of the Bulk Only Transport spec for
1216	 * an explanation of how this code works.
1217	 */
1218
1219	/* get CSW for device status */
1220	usb_stor_dbg(us, "Attempting to get CSW...\n");
1221	result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1222				bcs, US_BULK_CS_WRAP_LEN, &cswlen);
1223
1224	/*
1225	 * Some broken devices add unnecessary zero-length packets to the
1226	 * end of their data transfers.  Such packets show up as 0-length
1227	 * CSWs.  If we encounter such a thing, try to read the CSW again.
1228	 */
1229	if (result == USB_STOR_XFER_SHORT && cswlen == 0) {
1230		usb_stor_dbg(us, "Received 0-length CSW; retrying...\n");
1231		result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1232				bcs, US_BULK_CS_WRAP_LEN, &cswlen);
1233	}
1234
1235	/* did the attempt to read the CSW fail? */
1236	if (result == USB_STOR_XFER_STALLED) {
1237
1238		/* get the status again */
1239		usb_stor_dbg(us, "Attempting to get CSW (2nd try)...\n");
1240		result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1241				bcs, US_BULK_CS_WRAP_LEN, NULL);
1242	}
1243
1244	/* if we still have a failure at this point, we're in trouble */
1245	usb_stor_dbg(us, "Bulk status result = %d\n", result);
1246	if (result != USB_STOR_XFER_GOOD)
1247		return USB_STOR_TRANSPORT_ERROR;
1248
1249 skipped_data_phase:
1250	/* check bulk status */
1251	residue = le32_to_cpu(bcs->Residue);
1252	usb_stor_dbg(us, "Bulk Status S 0x%x T 0x%x R %u Stat 0x%x\n",
1253		     le32_to_cpu(bcs->Signature), bcs->Tag,
1254		     residue, bcs->Status);
1255	if (!(bcs->Tag == us->tag || (us->fflags & US_FL_BULK_IGNORE_TAG)) ||
1256		bcs->Status > US_BULK_STAT_PHASE) {
1257		usb_stor_dbg(us, "Bulk logical error\n");
1258		return USB_STOR_TRANSPORT_ERROR;
1259	}
1260
1261	/*
1262	 * Some broken devices report odd signatures, so we do not check them
1263	 * for validity against the spec. We store the first one we see,
1264	 * and check subsequent transfers for validity against this signature.
1265	 */
1266	if (!us->bcs_signature) {
1267		us->bcs_signature = bcs->Signature;
1268		if (us->bcs_signature != cpu_to_le32(US_BULK_CS_SIGN))
1269			usb_stor_dbg(us, "Learnt BCS signature 0x%08X\n",
1270				     le32_to_cpu(us->bcs_signature));
1271	} else if (bcs->Signature != us->bcs_signature) {
1272		usb_stor_dbg(us, "Signature mismatch: got %08X, expecting %08X\n",
1273			     le32_to_cpu(bcs->Signature),
1274			     le32_to_cpu(us->bcs_signature));
1275		return USB_STOR_TRANSPORT_ERROR;
1276	}
1277
1278	/*
1279	 * try to compute the actual residue, based on how much data
1280	 * was really transferred and what the device tells us
1281	 */
1282	if (residue && !(us->fflags & US_FL_IGNORE_RESIDUE)) {
1283
1284		/*
1285		 * Heuristically detect devices that generate bogus residues
1286		 * by seeing what happens with INQUIRY and READ CAPACITY
1287		 * commands.
1288		 */
1289		if (bcs->Status == US_BULK_STAT_OK &&
1290				scsi_get_resid(srb) == 0 &&
1291					((srb->cmnd[0] == INQUIRY &&
1292						transfer_length == 36) ||
1293					(srb->cmnd[0] == READ_CAPACITY &&
1294						transfer_length == 8))) {
1295			us->fflags |= US_FL_IGNORE_RESIDUE;
1296
1297		} else {
1298			residue = min(residue, transfer_length);
1299			scsi_set_resid(srb, max(scsi_get_resid(srb), residue));
 
1300		}
1301	}
1302
1303	/* based on the status code, we report good or bad */
1304	switch (bcs->Status) {
1305		case US_BULK_STAT_OK:
1306			/* device babbled -- return fake sense data */
1307			if (fake_sense) {
1308				memcpy(srb->sense_buffer, 
1309				       usb_stor_sense_invalidCDB, 
1310				       sizeof(usb_stor_sense_invalidCDB));
1311				return USB_STOR_TRANSPORT_NO_SENSE;
1312			}
1313
1314			/* command good -- note that data could be short */
1315			return USB_STOR_TRANSPORT_GOOD;
1316
1317		case US_BULK_STAT_FAIL:
1318			/* command failed */
1319			return USB_STOR_TRANSPORT_FAILED;
1320
1321		case US_BULK_STAT_PHASE:
1322			/*
1323			 * phase error -- note that a transport reset will be
1324			 * invoked by the invoke_transport() function
1325			 */
1326			return USB_STOR_TRANSPORT_ERROR;
1327	}
1328
1329	/* we should never get here, but if we do, we're in trouble */
1330	return USB_STOR_TRANSPORT_ERROR;
1331}
1332EXPORT_SYMBOL_GPL(usb_stor_Bulk_transport);
1333
1334/***********************************************************************
1335 * Reset routines
1336 ***********************************************************************/
1337
1338/*
1339 * This is the common part of the device reset code.
1340 *
1341 * It's handy that every transport mechanism uses the control endpoint for
1342 * resets.
1343 *
1344 * Basically, we send a reset with a 5-second timeout, so we don't get
1345 * jammed attempting to do the reset.
1346 */
1347static int usb_stor_reset_common(struct us_data *us,
1348		u8 request, u8 requesttype,
1349		u16 value, u16 index, void *data, u16 size)
1350{
1351	int result;
1352	int result2;
1353
1354	if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1355		usb_stor_dbg(us, "No reset during disconnect\n");
1356		return -EIO;
1357	}
1358
1359	result = usb_stor_control_msg(us, us->send_ctrl_pipe,
1360			request, requesttype, value, index, data, size,
1361			5*HZ);
1362	if (result < 0) {
1363		usb_stor_dbg(us, "Soft reset failed: %d\n", result);
1364		return result;
1365	}
1366
1367	/*
1368	 * Give the device some time to recover from the reset,
1369	 * but don't delay disconnect processing.
1370	 */
1371	wait_event_interruptible_timeout(us->delay_wait,
1372			test_bit(US_FLIDX_DISCONNECTING, &us->dflags),
1373			HZ*6);
1374	if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1375		usb_stor_dbg(us, "Reset interrupted by disconnect\n");
1376		return -EIO;
1377	}
1378
1379	usb_stor_dbg(us, "Soft reset: clearing bulk-in endpoint halt\n");
1380	result = usb_stor_clear_halt(us, us->recv_bulk_pipe);
1381
1382	usb_stor_dbg(us, "Soft reset: clearing bulk-out endpoint halt\n");
1383	result2 = usb_stor_clear_halt(us, us->send_bulk_pipe);
1384
1385	/* return a result code based on the result of the clear-halts */
1386	if (result >= 0)
1387		result = result2;
1388	if (result < 0)
1389		usb_stor_dbg(us, "Soft reset failed\n");
1390	else
1391		usb_stor_dbg(us, "Soft reset done\n");
1392	return result;
1393}
1394
1395/* This issues a CB[I] Reset to the device in question */
 
1396#define CB_RESET_CMD_SIZE	12
1397
1398int usb_stor_CB_reset(struct us_data *us)
1399{
1400	memset(us->iobuf, 0xFF, CB_RESET_CMD_SIZE);
1401	us->iobuf[0] = SEND_DIAGNOSTIC;
1402	us->iobuf[1] = 4;
1403	return usb_stor_reset_common(us, US_CBI_ADSC, 
1404				 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1405				 0, us->ifnum, us->iobuf, CB_RESET_CMD_SIZE);
1406}
1407EXPORT_SYMBOL_GPL(usb_stor_CB_reset);
1408
1409/*
1410 * This issues a Bulk-only Reset to the device in question, including
1411 * clearing the subsequent endpoint halts that may occur.
1412 */
1413int usb_stor_Bulk_reset(struct us_data *us)
1414{
1415	return usb_stor_reset_common(us, US_BULK_RESET_REQUEST, 
1416				 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1417				 0, us->ifnum, NULL, 0);
1418}
1419EXPORT_SYMBOL_GPL(usb_stor_Bulk_reset);
1420
1421/*
1422 * Issue a USB port reset to the device.  The caller must not hold
1423 * us->dev_mutex.
1424 */
1425int usb_stor_port_reset(struct us_data *us)
1426{
1427	int result;
1428
1429	/*for these devices we must use the class specific method */
1430	if (us->pusb_dev->quirks & USB_QUIRK_RESET)
1431		return -EPERM;
1432
1433	result = usb_lock_device_for_reset(us->pusb_dev, us->pusb_intf);
1434	if (result < 0)
1435		usb_stor_dbg(us, "unable to lock device for reset: %d\n",
1436			     result);
1437	else {
1438		/* Were we disconnected while waiting for the lock? */
1439		if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1440			result = -EIO;
1441			usb_stor_dbg(us, "No reset during disconnect\n");
1442		} else {
1443			result = usb_reset_device(us->pusb_dev);
1444			usb_stor_dbg(us, "usb_reset_device returns %d\n",
1445				     result);
1446		}
1447		usb_unlock_device(us->pusb_dev);
1448	}
1449	return result;
1450}