1/* Driver for USB Mass Storage compliant devices
 
   2 *
   3 * Current development and maintenance by:
   4 *   (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
   5 *
   6 * Developed with the assistance of:
   7 *   (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
   8 *   (c) 2000 Stephen J. Gowdy (SGowdy@lbl.gov)
   9 *   (c) 2002 Alan Stern <stern@rowland.org>
  10 *
  11 * Initial work by:
  12 *   (c) 1999 Michael Gee (michael@linuxspecific.com)
  13 *
  14 * This driver is based on the 'USB Mass Storage Class' document. This
  15 * describes in detail the protocol used to communicate with such
  16 * devices.  Clearly, the designers had SCSI and ATAPI commands in
  17 * mind when they created this document.  The commands are all very
  18 * similar to commands in the SCSI-II and ATAPI specifications.
  19 *
  20 * It is important to note that in a number of cases this class
  21 * exhibits class-specific exemptions from the USB specification.
  22 * Notably the usage of NAK, STALL and ACK differs from the norm, in
  23 * that they are used to communicate wait, failed and OK on commands.
  24 *
  25 * Also, for certain devices, the interrupt endpoint is used to convey
  26 * status of a command.
  27 *
  28 * Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
  29 * information about this driver.
  30 *
  31 * This program is free software; you can redistribute it and/or modify it
  32 * under the terms of the GNU General Public License as published by the
  33 * Free Software Foundation; either version 2, or (at your option) any
  34 * later version.
  35 *
  36 * This program is distributed in the hope that it will be useful, but
  37 * WITHOUT ANY WARRANTY; without even the implied warranty of
  38 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  39 * General Public License for more details.
  40 *
  41 * You should have received a copy of the GNU General Public License along
  42 * with this program; if not, write to the Free Software Foundation, Inc.,
  43 * 675 Mass Ave, Cambridge, MA 02139, USA.
  44 */
  45
  46#include <linux/sched.h>
  47#include <linux/gfp.h>
  48#include <linux/errno.h>
  49#include <linux/export.h>
  50
  51#include <linux/usb/quirks.h>
  52
  53#include <scsi/scsi.h>
  54#include <scsi/scsi_eh.h>
  55#include <scsi/scsi_device.h>
  56
  57#include "usb.h"
  58#include "transport.h"
  59#include "protocol.h"
  60#include "scsiglue.h"
  61#include "debug.h"
  62
  63#include <linux/blkdev.h>
  64#include "../../scsi/sd.h"
  65
  66
  67/***********************************************************************
  68 * Data transfer routines
  69 ***********************************************************************/
  70
  71/*
  72 * This is subtle, so pay attention:
  73 * ---------------------------------
  74 * We're very concerned about races with a command abort.  Hanging this code
  75 * is a sure fire way to hang the kernel.  (Note that this discussion applies
  76 * only to transactions resulting from a scsi queued-command, since only
  77 * these transactions are subject to a scsi abort.  Other transactions, such
  78 * as those occurring during device-specific initialization, must be handled
  79 * by a separate code path.)
  80 *
  81 * The abort function (usb_storage_command_abort() in scsiglue.c) first
  82 * sets the machine state and the ABORTING bit in us->dflags to prevent
  83 * new URBs from being submitted.  It then calls usb_stor_stop_transport()
  84 * below, which atomically tests-and-clears the URB_ACTIVE bit in us->dflags
  85 * to see if the current_urb needs to be stopped.  Likewise, the SG_ACTIVE
  86 * bit is tested to see if the current_sg scatter-gather request needs to be
  87 * stopped.  The timeout callback routine does much the same thing.
  88 *
  89 * When a disconnect occurs, the DISCONNECTING bit in us->dflags is set to
  90 * prevent new URBs from being submitted, and usb_stor_stop_transport() is
  91 * called to stop any ongoing requests.
  92 *
  93 * The submit function first verifies that the submitting is allowed
  94 * (neither ABORTING nor DISCONNECTING bits are set) and that the submit
  95 * completes without errors, and only then sets the URB_ACTIVE bit.  This
  96 * prevents the stop_transport() function from trying to cancel the URB
  97 * while the submit call is underway.  Next, the submit function must test
  98 * the flags to see if an abort or disconnect occurred during the submission
  99 * or before the URB_ACTIVE bit was set.  If so, it's essential to cancel
 100 * the URB if it hasn't been cancelled already (i.e., if the URB_ACTIVE bit
 101 * is still set).  Either way, the function must then wait for the URB to
 102 * finish.  Note that the URB can still be in progress even after a call to
 103 * usb_unlink_urb() returns.
 104 *
 105 * The idea is that (1) once the ABORTING or DISCONNECTING bit is set,
 106 * either the stop_transport() function or the submitting function
 107 * is guaranteed to call usb_unlink_urb() for an active URB,
 108 * and (2) test_and_clear_bit() prevents usb_unlink_urb() from being
 109 * called more than once or from being called during usb_submit_urb().
 110 */
 111
 112/* This is the completion handler which will wake us up when an URB
 
 113 * completes.
 114 */
 115static void usb_stor_blocking_completion(struct urb *urb)
 116{
 117	struct completion *urb_done_ptr = urb->context;
 118
 119	complete(urb_done_ptr);
 120}
 121
 122/* This is the common part of the URB message submission code
 
 123 *
 124 * All URBs from the usb-storage driver involved in handling a queued scsi
 125 * command _must_ pass through this function (or something like it) for the
 126 * abort mechanisms to work properly.
 127 */
 128static int usb_stor_msg_common(struct us_data *us, int timeout)
 129{
 130	struct completion urb_done;
 131	long timeleft;
 132	int status;
 133
 134	/* don't submit URBs during abort processing */
 135	if (test_bit(US_FLIDX_ABORTING, &us->dflags))
 136		return -EIO;
 137
 138	/* set up data structures for the wakeup system */
 139	init_completion(&urb_done);
 140
 141	/* fill the common fields in the URB */
 142	us->current_urb->context = &urb_done;
 143	us->current_urb->transfer_flags = 0;
 144
 145	/* we assume that if transfer_buffer isn't us->iobuf then it
 
 146	 * hasn't been mapped for DMA.  Yes, this is clunky, but it's
 147	 * easier than always having the caller tell us whether the
 148	 * transfer buffer has already been mapped. */
 
 149	if (us->current_urb->transfer_buffer == us->iobuf)
 150		us->current_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 151	us->current_urb->transfer_dma = us->iobuf_dma;
 152
 153	/* submit the URB */
 154	status = usb_submit_urb(us->current_urb, GFP_NOIO);
 155	if (status) {
 156		/* something went wrong */
 157		return status;
 158	}
 159
 160	/* since the URB has been submitted successfully, it's now okay
 161	 * to cancel it */
 
 
 162	set_bit(US_FLIDX_URB_ACTIVE, &us->dflags);
 163
 164	/* did an abort occur during the submission? */
 165	if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
 166
 167		/* cancel the URB, if it hasn't been cancelled already */
 168		if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
 169			usb_stor_dbg(us, "-- cancelling URB\n");
 170			usb_unlink_urb(us->current_urb);
 171		}
 172	}
 173 
 174	/* wait for the completion of the URB */
 175	timeleft = wait_for_completion_interruptible_timeout(
 176			&urb_done, timeout ? : MAX_SCHEDULE_TIMEOUT);
 177 
 178	clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags);
 179
 180	if (timeleft <= 0) {
 181		usb_stor_dbg(us, "%s -- cancelling URB\n",
 182			     timeleft == 0 ? "Timeout" : "Signal");
 183		usb_kill_urb(us->current_urb);
 184	}
 185
 186	/* return the URB status */
 187	return us->current_urb->status;
 188}
 189
 190/*
 191 * Transfer one control message, with timeouts, and allowing early
 192 * termination.  Return codes are usual -Exxx, *not* USB_STOR_XFER_xxx.
 193 */
 194int usb_stor_control_msg(struct us_data *us, unsigned int pipe,
 195		 u8 request, u8 requesttype, u16 value, u16 index, 
 196		 void *data, u16 size, int timeout)
 197{
 198	int status;
 199
 200	usb_stor_dbg(us, "rq=%02x rqtype=%02x value=%04x index=%02x len=%u\n",
 201		     request, requesttype, 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}
 221EXPORT_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 */
 235int 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	usb_stor_dbg(us, "result = %d\n", result);
 252	return result;
 253}
 254EXPORT_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 */
 264static int interpret_urb_result(struct us_data *us, unsigned int pipe,
 265		unsigned int length, int result, unsigned int partial)
 266{
 267	usb_stor_dbg(us, "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			usb_stor_dbg(us, "-- short transfer\n");
 275			return USB_STOR_XFER_SHORT;
 276		}
 277
 278		usb_stor_dbg(us, "-- 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			usb_stor_dbg(us, "-- stall on control pipe\n");
 287			return USB_STOR_XFER_STALLED;
 288		}
 289
 290		/* for other sorts of endpoint, clear the stall */
 291		usb_stor_dbg(us, "clearing endpoint halt for pipe 0x%x\n",
 292			     pipe);
 293		if (usb_stor_clear_halt(us, pipe) < 0)
 294			return USB_STOR_XFER_ERROR;
 295		return USB_STOR_XFER_STALLED;
 296
 297	/* babble - the device tried to send more than we wanted to read */
 298	case -EOVERFLOW:
 299		usb_stor_dbg(us, "-- babble\n");
 300		return USB_STOR_XFER_LONG;
 301
 302	/* the transfer was cancelled by abort, disconnect, or timeout */
 303	case -ECONNRESET:
 304		usb_stor_dbg(us, "-- transfer cancelled\n");
 305		return USB_STOR_XFER_ERROR;
 306
 307	/* short scatter-gather read transfer */
 308	case -EREMOTEIO:
 309		usb_stor_dbg(us, "-- short read transfer\n");
 310		return USB_STOR_XFER_SHORT;
 311
 312	/* abort or disconnect in progress */
 313	case -EIO:
 314		usb_stor_dbg(us, "-- abort or disconnect in progress\n");
 315		return USB_STOR_XFER_ERROR;
 316
 317	/* the catch-all error case */
 318	default:
 319		usb_stor_dbg(us, "-- unknown error\n");
 320		return USB_STOR_XFER_ERROR;
 321	}
 322}
 323
 324/*
 325 * Transfer one control message, without timeouts, but allowing early
 326 * termination.  Return codes are USB_STOR_XFER_xxx.
 327 */
 328int usb_stor_ctrl_transfer(struct us_data *us, unsigned int pipe,
 329		u8 request, u8 requesttype, u16 value, u16 index,
 330		void *data, u16 size)
 331{
 332	int result;
 333
 334	usb_stor_dbg(us, "rq=%02x rqtype=%02x value=%04x index=%02x len=%u\n",
 335		     request, requesttype, 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}
 353EXPORT_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 */
 362static 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	usb_stor_dbg(us, "xfer %u bytes\n", 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 */
 391int 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	usb_stor_dbg(us, "xfer %u bytes\n", 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}
 409EXPORT_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 */
 417static 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	usb_stor_dbg(us, "xfer %u bytes, %d entries\n", length, num_sg);
 429	result = usb_sg_init(&us->current_sg, us->pusb_dev, pipe, 0,
 430			sg, num_sg, length, GFP_NOIO);
 431	if (result) {
 432		usb_stor_dbg(us, "usb_sg_init returned %d\n", result);
 433		return USB_STOR_XFER_ERROR;
 434	}
 435
 436	/* since the block has been initialized successfully, it's now
 437	 * okay to cancel it */
 
 
 438	set_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
 439
 440	/* did an abort occur during the submission? */
 441	if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
 442
 443		/* cancel the request, if it hasn't been cancelled already */
 444		if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
 445			usb_stor_dbg(us, "-- cancelling sg request\n");
 446			usb_sg_cancel(&us->current_sg);
 447		}
 448	}
 449
 450	/* wait for the completion of the transfer */
 451	usb_sg_wait(&us->current_sg);
 452	clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
 453
 454	result = us->current_sg.status;
 455	if (act_len)
 456		*act_len = us->current_sg.bytes;
 457	return interpret_urb_result(us, pipe, length, result,
 458			us->current_sg.bytes);
 459}
 460
 461/*
 462 * Common used function. Transfer a complete command
 463 * via usb_stor_bulk_transfer_sglist() above. Set cmnd resid
 464 */
 465int usb_stor_bulk_srb(struct us_data* us, unsigned int pipe,
 466		      struct scsi_cmnd* srb)
 467{
 468	unsigned int partial;
 469	int result = usb_stor_bulk_transfer_sglist(us, pipe, scsi_sglist(srb),
 470				      scsi_sg_count(srb), scsi_bufflen(srb),
 471				      &partial);
 472
 473	scsi_set_resid(srb, scsi_bufflen(srb) - partial);
 474	return result;
 475}
 476EXPORT_SYMBOL_GPL(usb_stor_bulk_srb);
 477
 478/*
 479 * Transfer an entire SCSI command's worth of data payload over the bulk
 480 * pipe.
 481 *
 482 * Note that this uses usb_stor_bulk_transfer_buf() and
 483 * usb_stor_bulk_transfer_sglist() to achieve its goals --
 484 * this function simply determines whether we're going to use
 485 * scatter-gather or not, and acts appropriately.
 486 */
 487int usb_stor_bulk_transfer_sg(struct us_data* us, unsigned int pipe,
 488		void *buf, unsigned int length_left, int use_sg, int *residual)
 489{
 490	int result;
 491	unsigned int partial;
 492
 493	/* are we scatter-gathering? */
 494	if (use_sg) {
 495		/* use the usb core scatter-gather primitives */
 496		result = usb_stor_bulk_transfer_sglist(us, pipe,
 497				(struct scatterlist *) buf, use_sg,
 498				length_left, &partial);
 499		length_left -= partial;
 500	} else {
 501		/* no scatter-gather, just make the request */
 502		result = usb_stor_bulk_transfer_buf(us, pipe, buf, 
 503				length_left, &partial);
 504		length_left -= partial;
 505	}
 506
 507	/* store the residual and return the error code */
 508	if (residual)
 509		*residual = length_left;
 510	return result;
 511}
 512EXPORT_SYMBOL_GPL(usb_stor_bulk_transfer_sg);
 513
 514/***********************************************************************
 515 * Transport routines
 516 ***********************************************************************/
 517
 518/* There are so many devices that report the capacity incorrectly,
 
 519 * this routine was written to counteract some of the resulting
 520 * problems.
 521 */
 522static void last_sector_hacks(struct us_data *us, struct scsi_cmnd *srb)
 523{
 524	struct gendisk *disk;
 525	struct scsi_disk *sdkp;
 526	u32 sector;
 527
 528	/* To Report "Medium Error: Record Not Found */
 529	static unsigned char record_not_found[18] = {
 530		[0]	= 0x70,			/* current error */
 531		[2]	= MEDIUM_ERROR,		/* = 0x03 */
 532		[7]	= 0x0a,			/* additional length */
 533		[12]	= 0x14			/* Record Not Found */
 534	};
 535
 536	/* If last-sector problems can't occur, whether because the
 
 537	 * capacity was already decremented or because the device is
 538	 * known to report the correct capacity, then we don't need
 539	 * to do anything.
 540	 */
 541	if (!us->use_last_sector_hacks)
 542		return;
 543
 544	/* Was this command a READ(10) or a WRITE(10)? */
 545	if (srb->cmnd[0] != READ_10 && srb->cmnd[0] != WRITE_10)
 546		goto done;
 547
 548	/* Did this command access the last sector? */
 549	sector = (srb->cmnd[2] << 24) | (srb->cmnd[3] << 16) |
 550			(srb->cmnd[4] << 8) | (srb->cmnd[5]);
 551	disk = srb->request->rq_disk;
 552	if (!disk)
 553		goto done;
 554	sdkp = scsi_disk(disk);
 555	if (!sdkp)
 556		goto done;
 557	if (sector + 1 != sdkp->capacity)
 558		goto done;
 559
 560	if (srb->result == SAM_STAT_GOOD && scsi_get_resid(srb) == 0) {
 561
 562		/* The command succeeded.  We know this device doesn't
 
 563		 * have the last-sector bug, so stop checking it.
 564		 */
 565		us->use_last_sector_hacks = 0;
 566
 567	} else {
 568		/* The command failed.  Allow up to 3 retries in case this
 
 569		 * is some normal sort of failure.  After that, assume the
 570		 * capacity is wrong and we're trying to access the sector
 571		 * beyond the end.  Replace the result code and sense data
 572		 * with values that will cause the SCSI core to fail the
 573		 * command immediately, instead of going into an infinite
 574		 * (or even just a very long) retry loop.
 575		 */
 576		if (++us->last_sector_retries < 3)
 577			return;
 578		srb->result = SAM_STAT_CHECK_CONDITION;
 579		memcpy(srb->sense_buffer, record_not_found,
 580				sizeof(record_not_found));
 581	}
 582
 583 done:
 584	/* Don't reset the retry counter for TEST UNIT READY commands,
 
 585	 * because they get issued after device resets which might be
 586	 * caused by a failed last-sector access.
 587	 */
 588	if (srb->cmnd[0] != TEST_UNIT_READY)
 589		us->last_sector_retries = 0;
 590}
 591
 592/* Invoke the transport and basic error-handling/recovery methods
 
 593 *
 594 * This is used by the protocol layers to actually send the message to
 595 * the device and receive the response.
 596 */
 597void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
 598{
 599	int need_auto_sense;
 600	int result;
 601
 602	/* send the command to the transport layer */
 603	scsi_set_resid(srb, 0);
 604	result = us->transport(srb, us);
 605
 606	/* if the command gets aborted by the higher layers, we need to
 
 607	 * short-circuit all other processing
 608	 */
 609	if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
 610		usb_stor_dbg(us, "-- command was aborted\n");
 611		srb->result = DID_ABORT << 16;
 612		goto Handle_Errors;
 613	}
 614
 615	/* if there is a transport error, reset and don't auto-sense */
 616	if (result == USB_STOR_TRANSPORT_ERROR) {
 617		usb_stor_dbg(us, "-- transport indicates error, resetting\n");
 618		srb->result = DID_ERROR << 16;
 619		goto Handle_Errors;
 620	}
 621
 622	/* if the transport provided its own sense data, don't auto-sense */
 623	if (result == USB_STOR_TRANSPORT_NO_SENSE) {
 624		srb->result = SAM_STAT_CHECK_CONDITION;
 625		last_sector_hacks(us, srb);
 626		return;
 627	}
 628
 629	srb->result = SAM_STAT_GOOD;
 630
 631	/* Determine if we need to auto-sense
 
 632	 *
 633	 * I normally don't use a flag like this, but it's almost impossible
 634	 * to understand what's going on here if I don't.
 635	 */
 636	need_auto_sense = 0;
 637
 638	/*
 639	 * If we're running the CB transport, which is incapable
 640	 * of determining status on its own, we will auto-sense
 641	 * unless the operation involved a data-in transfer.  Devices
 642	 * can signal most data-in errors by stalling the bulk-in pipe.
 643	 */
 644	if ((us->protocol == USB_PR_CB || us->protocol == USB_PR_DPCM_USB) &&
 645			srb->sc_data_direction != DMA_FROM_DEVICE) {
 646		usb_stor_dbg(us, "-- CB transport device requiring auto-sense\n");
 647		need_auto_sense = 1;
 648	}
 649
 650	/*
 651	 * If we have a failure, we're going to do a REQUEST_SENSE 
 652	 * automatically.  Note that we differentiate between a command
 653	 * "failure" and an "error" in the transport mechanism.
 654	 */
 655	if (result == USB_STOR_TRANSPORT_FAILED) {
 656		usb_stor_dbg(us, "-- transport indicates command failure\n");
 657		need_auto_sense = 1;
 658	}
 659
 660	/*
 661	 * Determine if this device is SAT by seeing if the
 662	 * command executed successfully.  Otherwise we'll have
 663	 * to wait for at least one CHECK_CONDITION to determine
 664	 * SANE_SENSE support
 665	 */
 666	if (unlikely((srb->cmnd[0] == ATA_16 || srb->cmnd[0] == ATA_12) &&
 667	    result == USB_STOR_TRANSPORT_GOOD &&
 668	    !(us->fflags & US_FL_SANE_SENSE) &&
 669	    !(us->fflags & US_FL_BAD_SENSE) &&
 670	    !(srb->cmnd[2] & 0x20))) {
 671		usb_stor_dbg(us, "-- SAT supported, increasing auto-sense\n");
 672		us->fflags |= US_FL_SANE_SENSE;
 673	}
 674
 675	/*
 676	 * A short transfer on a command where we don't expect it
 677	 * is unusual, but it doesn't mean we need to auto-sense.
 678	 */
 679	if ((scsi_get_resid(srb) > 0) &&
 680	    !((srb->cmnd[0] == REQUEST_SENSE) ||
 681	      (srb->cmnd[0] == INQUIRY) ||
 682	      (srb->cmnd[0] == MODE_SENSE) ||
 683	      (srb->cmnd[0] == LOG_SENSE) ||
 684	      (srb->cmnd[0] == MODE_SENSE_10))) {
 685		usb_stor_dbg(us, "-- unexpectedly short transfer\n");
 686	}
 687
 688	/* Now, if we need to do the auto-sense, let's do it */
 689	if (need_auto_sense) {
 690		int temp_result;
 691		struct scsi_eh_save ses;
 692		int sense_size = US_SENSE_SIZE;
 693		struct scsi_sense_hdr sshdr;
 694		const u8 *scdd;
 695		u8 fm_ili;
 696
 697		/* device supports and needs bigger sense buffer */
 698		if (us->fflags & US_FL_SANE_SENSE)
 699			sense_size = ~0;
 700Retry_Sense:
 701		usb_stor_dbg(us, "Issuing auto-REQUEST_SENSE\n");
 702
 703		scsi_eh_prep_cmnd(srb, &ses, NULL, 0, sense_size);
 704
 705		/* FIXME: we must do the protocol translation here */
 706		if (us->subclass == USB_SC_RBC || us->subclass == USB_SC_SCSI ||
 707				us->subclass == USB_SC_CYP_ATACB)
 708			srb->cmd_len = 6;
 709		else
 710			srb->cmd_len = 12;
 711
 712		/* issue the auto-sense command */
 713		scsi_set_resid(srb, 0);
 714		temp_result = us->transport(us->srb, us);
 715
 716		/* let's clean up right away */
 717		scsi_eh_restore_cmnd(srb, &ses);
 718
 719		if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
 720			usb_stor_dbg(us, "-- auto-sense aborted\n");
 721			srb->result = DID_ABORT << 16;
 722
 723			/* If SANE_SENSE caused this problem, disable it */
 724			if (sense_size != US_SENSE_SIZE) {
 725				us->fflags &= ~US_FL_SANE_SENSE;
 726				us->fflags |= US_FL_BAD_SENSE;
 727			}
 728			goto Handle_Errors;
 729		}
 730
 731		/* Some devices claim to support larger sense but fail when
 
 732		 * trying to request it. When a transport failure happens
 733		 * using US_FS_SANE_SENSE, we always retry with a standard
 734		 * (small) sense request. This fixes some USB GSM modems
 735		 */
 736		if (temp_result == USB_STOR_TRANSPORT_FAILED &&
 737				sense_size != US_SENSE_SIZE) {
 738			usb_stor_dbg(us, "-- auto-sense failure, retry small sense\n");
 739			sense_size = US_SENSE_SIZE;
 740			us->fflags &= ~US_FL_SANE_SENSE;
 741			us->fflags |= US_FL_BAD_SENSE;
 742			goto Retry_Sense;
 743		}
 744
 745		/* Other failures */
 746		if (temp_result != USB_STOR_TRANSPORT_GOOD) {
 747			usb_stor_dbg(us, "-- auto-sense failure\n");
 748
 749			/* we skip the reset if this happens to be a
 
 750			 * multi-target device, since failure of an
 751			 * auto-sense is perfectly valid
 752			 */
 753			srb->result = DID_ERROR << 16;
 754			if (!(us->fflags & US_FL_SCM_MULT_TARG))
 755				goto Handle_Errors;
 756			return;
 757		}
 758
 759		/* If the sense data returned is larger than 18-bytes then we
 
 760		 * assume this device supports requesting more in the future.
 761		 * The response code must be 70h through 73h inclusive.
 762		 */
 763		if (srb->sense_buffer[7] > (US_SENSE_SIZE - 8) &&
 764		    !(us->fflags & US_FL_SANE_SENSE) &&
 765		    !(us->fflags & US_FL_BAD_SENSE) &&
 766		    (srb->sense_buffer[0] & 0x7C) == 0x70) {
 767			usb_stor_dbg(us, "-- SANE_SENSE support enabled\n");
 768			us->fflags |= US_FL_SANE_SENSE;
 769
 770			/* Indicate to the user that we truncated their sense
 
 771			 * because we didn't know it supported larger sense.
 772			 */
 773			usb_stor_dbg(us, "-- Sense data truncated to %i from %i\n",
 774				     US_SENSE_SIZE,
 775				     srb->sense_buffer[7] + 8);
 776			srb->sense_buffer[7] = (US_SENSE_SIZE - 8);
 777		}
 778
 779		scsi_normalize_sense(srb->sense_buffer, SCSI_SENSE_BUFFERSIZE,
 780				     &sshdr);
 781
 782		usb_stor_dbg(us, "-- Result from auto-sense is %d\n",
 783			     temp_result);
 784		usb_stor_dbg(us, "-- code: 0x%x, key: 0x%x, ASC: 0x%x, ASCQ: 0x%x\n",
 785			     sshdr.response_code, sshdr.sense_key,
 786			     sshdr.asc, sshdr.ascq);
 787#ifdef CONFIG_USB_STORAGE_DEBUG
 788		usb_stor_show_sense(us, sshdr.sense_key, sshdr.asc, sshdr.ascq);
 789#endif
 790
 791		/* set the result so the higher layers expect this data */
 792		srb->result = SAM_STAT_CHECK_CONDITION;
 793
 794		scdd = scsi_sense_desc_find(srb->sense_buffer,
 795					    SCSI_SENSE_BUFFERSIZE, 4);
 796		fm_ili = (scdd ? scdd[3] : srb->sense_buffer[2]) & 0xA0;
 797
 798		/* We often get empty sense data.  This could indicate that
 
 799		 * everything worked or that there was an unspecified
 800		 * problem.  We have to decide which.
 801		 */
 802		if (sshdr.sense_key == 0 && sshdr.asc == 0 && sshdr.ascq == 0 &&
 803		    fm_ili == 0) {
 804			/* If things are really okay, then let's show that.
 
 805			 * Zero out the sense buffer so the higher layers
 806			 * won't realize we did an unsolicited auto-sense.
 807			 */
 808			if (result == USB_STOR_TRANSPORT_GOOD) {
 809				srb->result = SAM_STAT_GOOD;
 810				srb->sense_buffer[0] = 0x0;
 811
 812			/* If there was a problem, report an unspecified
 
 813			 * hardware error to prevent the higher layers from
 814			 * entering an infinite retry loop.
 815			 */
 816			} else {
 817				srb->result = DID_ERROR << 16;
 818				if ((sshdr.response_code & 0x72) == 0x72)
 819					srb->sense_buffer[1] = HARDWARE_ERROR;
 820				else
 821					srb->sense_buffer[2] = HARDWARE_ERROR;
 822			}
 823		}
 824	}
 825
 826	/*
 827	 * Some devices don't work or return incorrect data the first
 828	 * time they get a READ(10) command, or for the first READ(10)
 829	 * after a media change.  If the INITIAL_READ10 flag is set,
 830	 * keep track of whether READ(10) commands succeed.  If the
 831	 * previous one succeeded and this one failed, set the REDO_READ10
 832	 * flag to force a retry.
 833	 */
 834	if (unlikely((us->fflags & US_FL_INITIAL_READ10) &&
 835			srb->cmnd[0] == READ_10)) {
 836		if (srb->result == SAM_STAT_GOOD) {
 837			set_bit(US_FLIDX_READ10_WORKED, &us->dflags);
 838		} else if (test_bit(US_FLIDX_READ10_WORKED, &us->dflags)) {
 839			clear_bit(US_FLIDX_READ10_WORKED, &us->dflags);
 840			set_bit(US_FLIDX_REDO_READ10, &us->dflags);
 841		}
 842
 843		/*
 844		 * Next, if the REDO_READ10 flag is set, return a result
 845		 * code that will cause the SCSI core to retry the READ(10)
 846		 * command immediately.
 847		 */
 848		if (test_bit(US_FLIDX_REDO_READ10, &us->dflags)) {
 849			clear_bit(US_FLIDX_REDO_READ10, &us->dflags);
 850			srb->result = DID_IMM_RETRY << 16;
 851			srb->sense_buffer[0] = 0;
 852		}
 853	}
 854
 855	/* Did we transfer less than the minimum amount required? */
 856	if ((srb->result == SAM_STAT_GOOD || srb->sense_buffer[2] == 0) &&
 857			scsi_bufflen(srb) - scsi_get_resid(srb) < srb->underflow)
 858		srb->result = DID_ERROR << 16;
 859
 860	last_sector_hacks(us, srb);
 861	return;
 862
 863	/* Error and abort processing: try to resynchronize with the device
 
 864	 * by issuing a port reset.  If that fails, try a class-specific
 865	 * device reset. */
 
 866  Handle_Errors:
 867
 868	/* Set the RESETTING bit, and clear the ABORTING bit so that
 869	 * the reset may proceed. */
 
 
 870	scsi_lock(us_to_host(us));
 871	set_bit(US_FLIDX_RESETTING, &us->dflags);
 872	clear_bit(US_FLIDX_ABORTING, &us->dflags);
 873	scsi_unlock(us_to_host(us));
 874
 875	/* We must release the device lock because the pre_reset routine
 876	 * will want to acquire it. */
 
 
 877	mutex_unlock(&us->dev_mutex);
 878	result = usb_stor_port_reset(us);
 879	mutex_lock(&us->dev_mutex);
 880
 881	if (result < 0) {
 882		scsi_lock(us_to_host(us));
 883		usb_stor_report_device_reset(us);
 884		scsi_unlock(us_to_host(us));
 885		us->transport_reset(us);
 886	}
 887	clear_bit(US_FLIDX_RESETTING, &us->dflags);
 888	last_sector_hacks(us, srb);
 889}
 890
 891/* Stop the current URB transfer */
 892void usb_stor_stop_transport(struct us_data *us)
 893{
 894	/* If the state machine is blocked waiting for an URB,
 
 895	 * let's wake it up.  The test_and_clear_bit() call
 896	 * guarantees that if a URB has just been submitted,
 897	 * it won't be cancelled more than once. */
 
 898	if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
 899		usb_stor_dbg(us, "-- cancelling URB\n");
 900		usb_unlink_urb(us->current_urb);
 901	}
 902
 903	/* If we are waiting for a scatter-gather operation, cancel it. */
 904	if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
 905		usb_stor_dbg(us, "-- cancelling sg request\n");
 906		usb_sg_cancel(&us->current_sg);
 907	}
 908}
 909
 910/*
 911 * Control/Bulk and Control/Bulk/Interrupt transport
 912 */
 913
 914int usb_stor_CB_transport(struct scsi_cmnd *srb, struct us_data *us)
 915{
 916	unsigned int transfer_length = scsi_bufflen(srb);
 917	unsigned int pipe = 0;
 918	int result;
 919
 920	/* COMMAND STAGE */
 921	/* let's send the command via the control pipe */
 
 
 
 
 
 922	result = usb_stor_ctrl_transfer(us, us->send_ctrl_pipe,
 923				      US_CBI_ADSC, 
 924				      USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0, 
 925				      us->ifnum, srb->cmnd, srb->cmd_len);
 926
 927	/* check the return code for the command */
 928	usb_stor_dbg(us, "Call to usb_stor_ctrl_transfer() returned %d\n",
 929		     result);
 930
 931	/* if we stalled the command, it means command failed */
 932	if (result == USB_STOR_XFER_STALLED) {
 933		return USB_STOR_TRANSPORT_FAILED;
 934	}
 935
 936	/* Uh oh... serious problem here */
 937	if (result != USB_STOR_XFER_GOOD) {
 938		return USB_STOR_TRANSPORT_ERROR;
 939	}
 940
 941	/* DATA STAGE */
 942	/* transfer the data payload for this command, if one exists*/
 943	if (transfer_length) {
 944		pipe = srb->sc_data_direction == DMA_FROM_DEVICE ? 
 945				us->recv_bulk_pipe : us->send_bulk_pipe;
 946		result = usb_stor_bulk_srb(us, pipe, srb);
 947		usb_stor_dbg(us, "CBI data stage result is 0x%x\n", result);
 948
 949		/* if we stalled the data transfer it means command failed */
 950		if (result == USB_STOR_XFER_STALLED)
 951			return USB_STOR_TRANSPORT_FAILED;
 952		if (result > USB_STOR_XFER_STALLED)
 953			return USB_STOR_TRANSPORT_ERROR;
 954	}
 955
 956	/* STATUS STAGE */
 957
 958	/* NOTE: CB does not have a status stage.  Silly, I know.  So
 
 959	 * we have to catch this at a higher level.
 960	 */
 961	if (us->protocol != USB_PR_CBI)
 962		return USB_STOR_TRANSPORT_GOOD;
 963
 964	result = usb_stor_intr_transfer(us, us->iobuf, 2);
 965	usb_stor_dbg(us, "Got interrupt data (0x%x, 0x%x)\n",
 966		     us->iobuf[0], us->iobuf[1]);
 967	if (result != USB_STOR_XFER_GOOD)
 968		return USB_STOR_TRANSPORT_ERROR;
 969
 970	/* UFI gives us ASC and ASCQ, like a request sense
 
 971	 *
 972	 * REQUEST_SENSE and INQUIRY don't affect the sense data on UFI
 973	 * devices, so we ignore the information for those commands.  Note
 974	 * that this means we could be ignoring a real error on these
 975	 * commands, but that can't be helped.
 976	 */
 977	if (us->subclass == USB_SC_UFI) {
 978		if (srb->cmnd[0] == REQUEST_SENSE ||
 979		    srb->cmnd[0] == INQUIRY)
 980			return USB_STOR_TRANSPORT_GOOD;
 981		if (us->iobuf[0])
 982			goto Failed;
 983		return USB_STOR_TRANSPORT_GOOD;
 984	}
 985
 986	/* If not UFI, we interpret the data as a result code 
 
 987	 * The first byte should always be a 0x0.
 988	 *
 989	 * Some bogus devices don't follow that rule.  They stuff the ASC
 990	 * into the first byte -- so if it's non-zero, call it a failure.
 991	 */
 992	if (us->iobuf[0]) {
 993		usb_stor_dbg(us, "CBI IRQ data showed reserved bType 0x%x\n",
 994			     us->iobuf[0]);
 995		goto Failed;
 996
 997	}
 998
 999	/* The second byte & 0x0F should be 0x0 for good, otherwise error */
1000	switch (us->iobuf[1] & 0x0F) {
1001		case 0x00: 
1002			return USB_STOR_TRANSPORT_GOOD;
1003		case 0x01: 
1004			goto Failed;
1005	}
1006	return USB_STOR_TRANSPORT_ERROR;
1007
1008	/* the CBI spec requires that the bulk pipe must be cleared
 
1009	 * following any data-in/out command failure (section 2.4.3.1.3)
1010	 */
1011  Failed:
1012	if (pipe)
1013		usb_stor_clear_halt(us, pipe);
1014	return USB_STOR_TRANSPORT_FAILED;
1015}
1016EXPORT_SYMBOL_GPL(usb_stor_CB_transport);
1017
1018/*
1019 * Bulk only transport
1020 */
1021
1022/* Determine what the maximum LUN supported is */
1023int usb_stor_Bulk_max_lun(struct us_data *us)
1024{
1025	int result;
1026
1027	/* issue the command */
1028	us->iobuf[0] = 0;
1029	result = usb_stor_control_msg(us, us->recv_ctrl_pipe,
1030				 US_BULK_GET_MAX_LUN, 
1031				 USB_DIR_IN | USB_TYPE_CLASS | 
1032				 USB_RECIP_INTERFACE,
1033				 0, us->ifnum, us->iobuf, 1, 10*HZ);
1034
1035	usb_stor_dbg(us, "GetMaxLUN command result is %d, data is %d\n",
1036		     result, us->iobuf[0]);
1037
1038	/*
1039	 * If we have a successful request, return the result if valid. The
1040	 * CBW LUN field is 4 bits wide, so the value reported by the device
1041	 * should fit into that.
1042	 */
1043	if (result > 0) {
1044		if (us->iobuf[0] < 16) {
1045			return us->iobuf[0];
1046		} else {
1047			dev_info(&us->pusb_intf->dev,
1048				 "Max LUN %d is not valid, using 0 instead",
1049				 us->iobuf[0]);
1050		}
1051	}
1052
1053	/*
1054	 * Some devices don't like GetMaxLUN.  They may STALL the control
1055	 * pipe, they may return a zero-length result, they may do nothing at
1056	 * all and timeout, or they may fail in even more bizarrely creative
1057	 * ways.  In these cases the best approach is to use the default
1058	 * value: only one LUN.
1059	 */
1060	return 0;
1061}
1062
1063int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us)
1064{
1065	struct bulk_cb_wrap *bcb = (struct bulk_cb_wrap *) us->iobuf;
1066	struct bulk_cs_wrap *bcs = (struct bulk_cs_wrap *) us->iobuf;
1067	unsigned int transfer_length = scsi_bufflen(srb);
1068	unsigned int residue;
1069	int result;
1070	int fake_sense = 0;
1071	unsigned int cswlen;
1072	unsigned int cbwlen = US_BULK_CB_WRAP_LEN;
1073
1074	/* Take care of BULK32 devices; set extra byte to 0 */
1075	if (unlikely(us->fflags & US_FL_BULK32)) {
1076		cbwlen = 32;
1077		us->iobuf[31] = 0;
1078	}
1079
1080	/* set up the command wrapper */
1081	bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
1082	bcb->DataTransferLength = cpu_to_le32(transfer_length);
1083	bcb->Flags = srb->sc_data_direction == DMA_FROM_DEVICE ?
1084		US_BULK_FLAG_IN : 0;
1085	bcb->Tag = ++us->tag;
1086	bcb->Lun = srb->device->lun;
1087	if (us->fflags & US_FL_SCM_MULT_TARG)
1088		bcb->Lun |= srb->device->id << 4;
1089	bcb->Length = srb->cmd_len;
1090
1091	/* copy the command payload */
1092	memset(bcb->CDB, 0, sizeof(bcb->CDB));
1093	memcpy(bcb->CDB, srb->cmnd, bcb->Length);
1094
1095	/* send it to out endpoint */
1096	usb_stor_dbg(us, "Bulk Command S 0x%x T 0x%x L %d F %d Trg %d LUN %d CL %d\n",
1097		     le32_to_cpu(bcb->Signature), bcb->Tag,
1098		     le32_to_cpu(bcb->DataTransferLength), bcb->Flags,
1099		     (bcb->Lun >> 4), (bcb->Lun & 0x0F),
1100		     bcb->Length);
1101	result = usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
1102				bcb, cbwlen, NULL);
1103	usb_stor_dbg(us, "Bulk command transfer result=%d\n", result);
1104	if (result != USB_STOR_XFER_GOOD)
1105		return USB_STOR_TRANSPORT_ERROR;
1106
1107	/* DATA STAGE */
1108	/* send/receive data payload, if there is any */
1109
1110	/* Some USB-IDE converter chips need a 100us delay between the
 
1111	 * command phase and the data phase.  Some devices need a little
1112	 * more than that, probably because of clock rate inaccuracies. */
 
1113	if (unlikely(us->fflags & US_FL_GO_SLOW))
1114		usleep_range(125, 150);
1115
1116	if (transfer_length) {
1117		unsigned int pipe = srb->sc_data_direction == DMA_FROM_DEVICE ? 
1118				us->recv_bulk_pipe : us->send_bulk_pipe;
1119		result = usb_stor_bulk_srb(us, pipe, srb);
1120		usb_stor_dbg(us, "Bulk data transfer result 0x%x\n", result);
1121		if (result == USB_STOR_XFER_ERROR)
1122			return USB_STOR_TRANSPORT_ERROR;
1123
1124		/* If the device tried to send back more data than the
 
1125		 * amount requested, the spec requires us to transfer
1126		 * the CSW anyway.  Since there's no point retrying the
1127		 * the command, we'll return fake sense data indicating
1128		 * Illegal Request, Invalid Field in CDB.
1129		 */
1130		if (result == USB_STOR_XFER_LONG)
1131			fake_sense = 1;
1132
1133		/*
1134		 * Sometimes a device will mistakenly skip the data phase
1135		 * and go directly to the status phase without sending a
1136		 * zero-length packet.  If we get a 13-byte response here,
1137		 * check whether it really is a CSW.
1138		 */
1139		if (result == USB_STOR_XFER_SHORT &&
1140				srb->sc_data_direction == DMA_FROM_DEVICE &&
1141				transfer_length - scsi_get_resid(srb) ==
1142					US_BULK_CS_WRAP_LEN) {
1143			struct scatterlist *sg = NULL;
1144			unsigned int offset = 0;
1145
1146			if (usb_stor_access_xfer_buf((unsigned char *) bcs,
1147					US_BULK_CS_WRAP_LEN, srb, &sg,
1148					&offset, FROM_XFER_BUF) ==
1149						US_BULK_CS_WRAP_LEN &&
1150					bcs->Signature ==
1151						cpu_to_le32(US_BULK_CS_SIGN)) {
1152				usb_stor_dbg(us, "Device skipped data phase\n");
1153				scsi_set_resid(srb, transfer_length);
1154				goto skipped_data_phase;
1155			}
1156		}
1157	}
1158
1159	/* See flow chart on pg 15 of the Bulk Only Transport spec for
 
1160	 * an explanation of how this code works.
1161	 */
1162
1163	/* get CSW for device status */
1164	usb_stor_dbg(us, "Attempting to get CSW...\n");
1165	result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1166				bcs, US_BULK_CS_WRAP_LEN, &cswlen);
1167
1168	/* Some broken devices add unnecessary zero-length packets to the
 
1169	 * end of their data transfers.  Such packets show up as 0-length
1170	 * CSWs.  If we encounter such a thing, try to read the CSW again.
1171	 */
1172	if (result == USB_STOR_XFER_SHORT && cswlen == 0) {
1173		usb_stor_dbg(us, "Received 0-length CSW; retrying...\n");
1174		result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1175				bcs, US_BULK_CS_WRAP_LEN, &cswlen);
1176	}
1177
1178	/* did the attempt to read the CSW fail? */
1179	if (result == USB_STOR_XFER_STALLED) {
1180
1181		/* get the status again */
1182		usb_stor_dbg(us, "Attempting to get CSW (2nd try)...\n");
1183		result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
1184				bcs, US_BULK_CS_WRAP_LEN, NULL);
1185	}
1186
1187	/* if we still have a failure at this point, we're in trouble */
1188	usb_stor_dbg(us, "Bulk status result = %d\n", result);
1189	if (result != USB_STOR_XFER_GOOD)
1190		return USB_STOR_TRANSPORT_ERROR;
1191
1192 skipped_data_phase:
1193	/* check bulk status */
1194	residue = le32_to_cpu(bcs->Residue);
1195	usb_stor_dbg(us, "Bulk Status S 0x%x T 0x%x R %u Stat 0x%x\n",
1196		     le32_to_cpu(bcs->Signature), bcs->Tag,
1197		     residue, bcs->Status);
1198	if (!(bcs->Tag == us->tag || (us->fflags & US_FL_BULK_IGNORE_TAG)) ||
1199		bcs->Status > US_BULK_STAT_PHASE) {
1200		usb_stor_dbg(us, "Bulk logical error\n");
1201		return USB_STOR_TRANSPORT_ERROR;
1202	}
1203
1204	/* Some broken devices report odd signatures, so we do not check them
 
1205	 * for validity against the spec. We store the first one we see,
1206	 * and check subsequent transfers for validity against this signature.
1207	 */
1208	if (!us->bcs_signature) {
1209		us->bcs_signature = bcs->Signature;
1210		if (us->bcs_signature != cpu_to_le32(US_BULK_CS_SIGN))
1211			usb_stor_dbg(us, "Learnt BCS signature 0x%08X\n",
1212				     le32_to_cpu(us->bcs_signature));
1213	} else if (bcs->Signature != us->bcs_signature) {
1214		usb_stor_dbg(us, "Signature mismatch: got %08X, expecting %08X\n",
1215			     le32_to_cpu(bcs->Signature),
1216			     le32_to_cpu(us->bcs_signature));
1217		return USB_STOR_TRANSPORT_ERROR;
1218	}
1219
1220	/* try to compute the actual residue, based on how much data
1221	 * was really transferred and what the device tells us */
 
 
1222	if (residue && !(us->fflags & US_FL_IGNORE_RESIDUE)) {
1223
1224		/* Heuristically detect devices that generate bogus residues
 
1225		 * by seeing what happens with INQUIRY and READ CAPACITY
1226		 * commands.
1227		 */
1228		if (bcs->Status == US_BULK_STAT_OK &&
1229				scsi_get_resid(srb) == 0 &&
1230					((srb->cmnd[0] == INQUIRY &&
1231						transfer_length == 36) ||
1232					(srb->cmnd[0] == READ_CAPACITY &&
1233						transfer_length == 8))) {
1234			us->fflags |= US_FL_IGNORE_RESIDUE;
1235
1236		} else {
1237			residue = min(residue, transfer_length);
1238			scsi_set_resid(srb, max(scsi_get_resid(srb),
1239			                                       (int) residue));
1240		}
1241	}
1242
1243	/* based on the status code, we report good or bad */
1244	switch (bcs->Status) {
1245		case US_BULK_STAT_OK:
1246			/* device babbled -- return fake sense data */
1247			if (fake_sense) {
1248				memcpy(srb->sense_buffer, 
1249				       usb_stor_sense_invalidCDB, 
1250				       sizeof(usb_stor_sense_invalidCDB));
1251				return USB_STOR_TRANSPORT_NO_SENSE;
1252			}
1253
1254			/* command good -- note that data could be short */
1255			return USB_STOR_TRANSPORT_GOOD;
1256
1257		case US_BULK_STAT_FAIL:
1258			/* command failed */
1259			return USB_STOR_TRANSPORT_FAILED;
1260
1261		case US_BULK_STAT_PHASE:
1262			/* phase error -- note that a transport reset will be
 
1263			 * invoked by the invoke_transport() function
1264			 */
1265			return USB_STOR_TRANSPORT_ERROR;
1266	}
1267
1268	/* we should never get here, but if we do, we're in trouble */
1269	return USB_STOR_TRANSPORT_ERROR;
1270}
1271EXPORT_SYMBOL_GPL(usb_stor_Bulk_transport);
1272
1273/***********************************************************************
1274 * Reset routines
1275 ***********************************************************************/
1276
1277/* This is the common part of the device reset code.
 
1278 *
1279 * It's handy that every transport mechanism uses the control endpoint for
1280 * resets.
1281 *
1282 * Basically, we send a reset with a 5-second timeout, so we don't get
1283 * jammed attempting to do the reset.
1284 */
1285static int usb_stor_reset_common(struct us_data *us,
1286		u8 request, u8 requesttype,
1287		u16 value, u16 index, void *data, u16 size)
1288{
1289	int result;
1290	int result2;
1291
1292	if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1293		usb_stor_dbg(us, "No reset during disconnect\n");
1294		return -EIO;
1295	}
1296
1297	result = usb_stor_control_msg(us, us->send_ctrl_pipe,
1298			request, requesttype, value, index, data, size,
1299			5*HZ);
1300	if (result < 0) {
1301		usb_stor_dbg(us, "Soft reset failed: %d\n", result);
1302		return result;
1303	}
1304
1305	/* Give the device some time to recover from the reset,
1306	 * but don't delay disconnect processing. */
 
 
1307	wait_event_interruptible_timeout(us->delay_wait,
1308			test_bit(US_FLIDX_DISCONNECTING, &us->dflags),
1309			HZ*6);
1310	if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1311		usb_stor_dbg(us, "Reset interrupted by disconnect\n");
1312		return -EIO;
1313	}
1314
1315	usb_stor_dbg(us, "Soft reset: clearing bulk-in endpoint halt\n");
1316	result = usb_stor_clear_halt(us, us->recv_bulk_pipe);
1317
1318	usb_stor_dbg(us, "Soft reset: clearing bulk-out endpoint halt\n");
1319	result2 = usb_stor_clear_halt(us, us->send_bulk_pipe);
1320
1321	/* return a result code based on the result of the clear-halts */
1322	if (result >= 0)
1323		result = result2;
1324	if (result < 0)
1325		usb_stor_dbg(us, "Soft reset failed\n");
1326	else
1327		usb_stor_dbg(us, "Soft reset done\n");
1328	return result;
1329}
1330
1331/* This issues a CB[I] Reset to the device in question
1332 */
1333#define CB_RESET_CMD_SIZE	12
1334
1335int usb_stor_CB_reset(struct us_data *us)
1336{
1337	memset(us->iobuf, 0xFF, CB_RESET_CMD_SIZE);
1338	us->iobuf[0] = SEND_DIAGNOSTIC;
1339	us->iobuf[1] = 4;
1340	return usb_stor_reset_common(us, US_CBI_ADSC, 
1341				 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1342				 0, us->ifnum, us->iobuf, CB_RESET_CMD_SIZE);
1343}
1344EXPORT_SYMBOL_GPL(usb_stor_CB_reset);
1345
1346/* This issues a Bulk-only Reset to the device in question, including
 
1347 * clearing the subsequent endpoint halts that may occur.
1348 */
1349int usb_stor_Bulk_reset(struct us_data *us)
1350{
1351	return usb_stor_reset_common(us, US_BULK_RESET_REQUEST, 
1352				 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1353				 0, us->ifnum, NULL, 0);
1354}
1355EXPORT_SYMBOL_GPL(usb_stor_Bulk_reset);
1356
1357/* Issue a USB port reset to the device.  The caller must not hold
 
1358 * us->dev_mutex.
1359 */
1360int usb_stor_port_reset(struct us_data *us)
1361{
1362	int result;
1363
1364	/*for these devices we must use the class specific method */
1365	if (us->pusb_dev->quirks & USB_QUIRK_RESET)
1366		return -EPERM;
1367
1368	result = usb_lock_device_for_reset(us->pusb_dev, us->pusb_intf);
1369	if (result < 0)
1370		usb_stor_dbg(us, "unable to lock device for reset: %d\n",
1371			     result);
1372	else {
1373		/* Were we disconnected while waiting for the lock? */
1374		if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
1375			result = -EIO;
1376			usb_stor_dbg(us, "No reset during disconnect\n");
1377		} else {
1378			result = usb_reset_device(us->pusb_dev);
1379			usb_stor_dbg(us, "usb_reset_device returns %d\n",
1380				     result);
1381		}
1382		usb_unlock_device(us->pusb_dev);
1383	}
1384	return result;
1385}