5c030b080d4c59c99f62eb65628d4bc5004ed005
[linux-2.6.git] / drivers / usb / gadget / file_storage.c
1 /*
2  * file_storage.c -- File-backed USB Storage Gadget, for USB development
3  *
4  * Copyright (C) 2003-2008 Alan Stern
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions, and the following disclaimer,
12  *    without modification.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. The names of the above-listed copyright holders may not be used
17  *    to endorse or promote products derived from this software without
18  *    specific prior written permission.
19  *
20  * ALTERNATIVELY, this software may be distributed under the terms of the
21  * GNU General Public License ("GPL") as published by the Free Software
22  * Foundation, either version 2 of that License or (at your option) any
23  * later version.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
26  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
27  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
29  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
30  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
31  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
32  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
33  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
34  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
35  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36  */
37
38
39 /*
40  * The File-backed Storage Gadget acts as a USB Mass Storage device,
41  * appearing to the host as a disk drive or as a CD-ROM drive.  In addition
42  * to providing an example of a genuinely useful gadget driver for a USB
43  * device, it also illustrates a technique of double-buffering for increased
44  * throughput.  Last but not least, it gives an easy way to probe the
45  * behavior of the Mass Storage drivers in a USB host.
46  *
47  * Backing storage is provided by a regular file or a block device, specified
48  * by the "file" module parameter.  Access can be limited to read-only by
49  * setting the optional "ro" module parameter.  (For CD-ROM emulation,
50  * access is always read-only.)  The gadget will indicate that it has
51  * removable media if the optional "removable" module parameter is set.
52  *
53  * The gadget supports the Control-Bulk (CB), Control-Bulk-Interrupt (CBI),
54  * and Bulk-Only (also known as Bulk-Bulk-Bulk or BBB) transports, selected
55  * by the optional "transport" module parameter.  It also supports the
56  * following protocols: RBC (0x01), ATAPI or SFF-8020i (0x02), QIC-157 (0c03),
57  * UFI (0x04), SFF-8070i (0x05), and transparent SCSI (0x06), selected by
58  * the optional "protocol" module parameter.  In addition, the default
59  * Vendor ID, Product ID, and release number can be overridden.
60  *
61  * There is support for multiple logical units (LUNs), each of which has
62  * its own backing file.  The number of LUNs can be set using the optional
63  * "luns" module parameter (anywhere from 1 to 8), and the corresponding
64  * files are specified using comma-separated lists for "file" and "ro".
65  * The default number of LUNs is taken from the number of "file" elements;
66  * it is 1 if "file" is not given.  If "removable" is not set then a backing
67  * file must be specified for each LUN.  If it is set, then an unspecified
68  * or empty backing filename means the LUN's medium is not loaded.  Ideally
69  * each LUN would be settable independently as a disk drive or a CD-ROM
70  * drive, but currently all LUNs have to be the same type.  The CD-ROM
71  * emulation includes a single data track and no audio tracks; hence there
72  * need be only one backing file per LUN.  Note also that the CD-ROM block
73  * length is set to 512 rather than the more common value 2048.
74  *
75  * Requirements are modest; only a bulk-in and a bulk-out endpoint are
76  * needed (an interrupt-out endpoint is also needed for CBI).  The memory
77  * requirement amounts to two 16K buffers, size configurable by a parameter.
78  * Support is included for both full-speed and high-speed operation.
79  *
80  * Note that the driver is slightly non-portable in that it assumes a
81  * single memory/DMA buffer will be useable for bulk-in, bulk-out, and
82  * interrupt-in endpoints.  With most device controllers this isn't an
83  * issue, but there may be some with hardware restrictions that prevent
84  * a buffer from being used by more than one endpoint.
85  *
86  * Module options:
87  *
88  *      file=filename[,filename...]
89  *                              Required if "removable" is not set, names of
90  *                                      the files or block devices used for
91  *                                      backing storage
92  *      ro=b[,b...]             Default false, booleans for read-only access
93  *      removable               Default false, boolean for removable media
94  *      luns=N                  Default N = number of filenames, number of
95  *                                      LUNs to support
96  *      stall                   Default determined according to the type of
97  *                                      USB device controller (usually true),
98  *                                      boolean to permit the driver to halt
99  *                                      bulk endpoints
100  *      cdrom                   Default false, boolean for whether to emulate
101  *                                      a CD-ROM drive
102  *      transport=XXX           Default BBB, transport name (CB, CBI, or BBB)
103  *      protocol=YYY            Default SCSI, protocol name (RBC, 8020 or
104  *                                      ATAPI, QIC, UFI, 8070, or SCSI;
105  *                                      also 1 - 6)
106  *      vendor=0xVVVV           Default 0x0525 (NetChip), USB Vendor ID
107  *      product=0xPPPP          Default 0xa4a5 (FSG), USB Product ID
108  *      release=0xRRRR          Override the USB release number (bcdDevice)
109  *      buflen=N                Default N=16384, buffer size used (will be
110  *                                      rounded down to a multiple of
111  *                                      PAGE_CACHE_SIZE)
112  *
113  * If CONFIG_USB_FILE_STORAGE_TEST is not set, only the "file", "ro",
114  * "removable", "luns", "stall", and "cdrom" options are available; default
115  * values are used for everything else.
116  *
117  * The pathnames of the backing files and the ro settings are available in
118  * the attribute files "file" and "ro" in the lun<n> subdirectory of the
119  * gadget's sysfs directory.  If the "removable" option is set, writing to
120  * these files will simulate ejecting/loading the medium (writing an empty
121  * line means eject) and adjusting a write-enable tab.  Changes to the ro
122  * setting are not allowed when the medium is loaded or if CD-ROM emulation
123  * is being used.
124  *
125  * This gadget driver is heavily based on "Gadget Zero" by David Brownell.
126  * The driver's SCSI command interface was based on the "Information
127  * technology - Small Computer System Interface - 2" document from
128  * X3T9.2 Project 375D, Revision 10L, 7-SEP-93, available at
129  * <http://www.t10.org/ftp/t10/drafts/s2/s2-r10l.pdf>.  The single exception
130  * is opcode 0x23 (READ FORMAT CAPACITIES), which was based on the
131  * "Universal Serial Bus Mass Storage Class UFI Command Specification"
132  * document, Revision 1.0, December 14, 1998, available at
133  * <http://www.usb.org/developers/devclass_docs/usbmass-ufi10.pdf>.
134  */
135
136
137 /*
138  *                              Driver Design
139  *
140  * The FSG driver is fairly straightforward.  There is a main kernel
141  * thread that handles most of the work.  Interrupt routines field
142  * callbacks from the controller driver: bulk- and interrupt-request
143  * completion notifications, endpoint-0 events, and disconnect events.
144  * Completion events are passed to the main thread by wakeup calls.  Many
145  * ep0 requests are handled at interrupt time, but SetInterface,
146  * SetConfiguration, and device reset requests are forwarded to the
147  * thread in the form of "exceptions" using SIGUSR1 signals (since they
148  * should interrupt any ongoing file I/O operations).
149  *
150  * The thread's main routine implements the standard command/data/status
151  * parts of a SCSI interaction.  It and its subroutines are full of tests
152  * for pending signals/exceptions -- all this polling is necessary since
153  * the kernel has no setjmp/longjmp equivalents.  (Maybe this is an
154  * indication that the driver really wants to be running in userspace.)
155  * An important point is that so long as the thread is alive it keeps an
156  * open reference to the backing file.  This will prevent unmounting
157  * the backing file's underlying filesystem and could cause problems
158  * during system shutdown, for example.  To prevent such problems, the
159  * thread catches INT, TERM, and KILL signals and converts them into
160  * an EXIT exception.
161  *
162  * In normal operation the main thread is started during the gadget's
163  * fsg_bind() callback and stopped during fsg_unbind().  But it can also
164  * exit when it receives a signal, and there's no point leaving the
165  * gadget running when the thread is dead.  So just before the thread
166  * exits, it deregisters the gadget driver.  This makes things a little
167  * tricky: The driver is deregistered at two places, and the exiting
168  * thread can indirectly call fsg_unbind() which in turn can tell the
169  * thread to exit.  The first problem is resolved through the use of the
170  * REGISTERED atomic bitflag; the driver will only be deregistered once.
171  * The second problem is resolved by having fsg_unbind() check
172  * fsg->state; it won't try to stop the thread if the state is already
173  * FSG_STATE_TERMINATED.
174  *
175  * To provide maximum throughput, the driver uses a circular pipeline of
176  * buffer heads (struct fsg_buffhd).  In principle the pipeline can be
177  * arbitrarily long; in practice the benefits don't justify having more
178  * than 2 stages (i.e., double buffering).  But it helps to think of the
179  * pipeline as being a long one.  Each buffer head contains a bulk-in and
180  * a bulk-out request pointer (since the buffer can be used for both
181  * output and input -- directions always are given from the host's
182  * point of view) as well as a pointer to the buffer and various state
183  * variables.
184  *
185  * Use of the pipeline follows a simple protocol.  There is a variable
186  * (fsg->next_buffhd_to_fill) that points to the next buffer head to use.
187  * At any time that buffer head may still be in use from an earlier
188  * request, so each buffer head has a state variable indicating whether
189  * it is EMPTY, FULL, or BUSY.  Typical use involves waiting for the
190  * buffer head to be EMPTY, filling the buffer either by file I/O or by
191  * USB I/O (during which the buffer head is BUSY), and marking the buffer
192  * head FULL when the I/O is complete.  Then the buffer will be emptied
193  * (again possibly by USB I/O, during which it is marked BUSY) and
194  * finally marked EMPTY again (possibly by a completion routine).
195  *
196  * A module parameter tells the driver to avoid stalling the bulk
197  * endpoints wherever the transport specification allows.  This is
198  * necessary for some UDCs like the SuperH, which cannot reliably clear a
199  * halt on a bulk endpoint.  However, under certain circumstances the
200  * Bulk-only specification requires a stall.  In such cases the driver
201  * will halt the endpoint and set a flag indicating that it should clear
202  * the halt in software during the next device reset.  Hopefully this
203  * will permit everything to work correctly.  Furthermore, although the
204  * specification allows the bulk-out endpoint to halt when the host sends
205  * too much data, implementing this would cause an unavoidable race.
206  * The driver will always use the "no-stall" approach for OUT transfers.
207  *
208  * One subtle point concerns sending status-stage responses for ep0
209  * requests.  Some of these requests, such as device reset, can involve
210  * interrupting an ongoing file I/O operation, which might take an
211  * arbitrarily long time.  During that delay the host might give up on
212  * the original ep0 request and issue a new one.  When that happens the
213  * driver should not notify the host about completion of the original
214  * request, as the host will no longer be waiting for it.  So the driver
215  * assigns to each ep0 request a unique tag, and it keeps track of the
216  * tag value of the request associated with a long-running exception
217  * (device-reset, interface-change, or configuration-change).  When the
218  * exception handler is finished, the status-stage response is submitted
219  * only if the current ep0 request tag is equal to the exception request
220  * tag.  Thus only the most recently received ep0 request will get a
221  * status-stage response.
222  *
223  * Warning: This driver source file is too long.  It ought to be split up
224  * into a header file plus about 3 separate .c files, to handle the details
225  * of the Gadget, USB Mass Storage, and SCSI protocols.
226  */
227
228
229 /* #define VERBOSE_DEBUG */
230 /* #define DUMP_MSGS */
231
232
233 #include <linux/blkdev.h>
234 #include <linux/completion.h>
235 #include <linux/dcache.h>
236 #include <linux/delay.h>
237 #include <linux/device.h>
238 #include <linux/fcntl.h>
239 #include <linux/file.h>
240 #include <linux/fs.h>
241 #include <linux/kref.h>
242 #include <linux/kthread.h>
243 #include <linux/limits.h>
244 #include <linux/rwsem.h>
245 #include <linux/slab.h>
246 #include <linux/spinlock.h>
247 #include <linux/string.h>
248 #include <linux/freezer.h>
249 #include <linux/utsname.h>
250
251 #include <linux/usb/ch9.h>
252 #include <linux/usb/gadget.h>
253
254 #include "gadget_chips.h"
255
256
257
258 /*
259  * Kbuild is not very cooperative with respect to linking separately
260  * compiled library objects into one module.  So for now we won't use
261  * separate compilation ... ensuring init/exit sections work to shrink
262  * the runtime footprint, and giving us at least some parts of what
263  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
264  */
265 #include "usbstring.c"
266 #include "config.c"
267 #include "epautoconf.c"
268
269 /*-------------------------------------------------------------------------*/
270
271 #define DRIVER_DESC             "File-backed Storage Gadget"
272 #define DRIVER_NAME             "g_file_storage"
273 #define DRIVER_VERSION          "20 November 2008"
274
275 static const char longname[] = DRIVER_DESC;
276 static const char shortname[] = DRIVER_NAME;
277
278 MODULE_DESCRIPTION(DRIVER_DESC);
279 MODULE_AUTHOR("Alan Stern");
280 MODULE_LICENSE("Dual BSD/GPL");
281
282 /* Thanks to NetChip Technologies for donating this product ID.
283  *
284  * DO NOT REUSE THESE IDs with any other driver!!  Ever!!
285  * Instead:  allocate your own, using normal USB-IF procedures. */
286 #define DRIVER_VENDOR_ID        0x0525  // NetChip
287 #define DRIVER_PRODUCT_ID       0xa4a5  // Linux-USB File-backed Storage Gadget
288
289
290 /*
291  * This driver assumes self-powered hardware and has no way for users to
292  * trigger remote wakeup.  It uses autoconfiguration to select endpoints
293  * and endpoint addresses.
294  */
295
296
297 /*-------------------------------------------------------------------------*/
298
299 #define LDBG(lun,fmt,args...) \
300         dev_dbg(&(lun)->dev , fmt , ## args)
301 #define MDBG(fmt,args...) \
302         pr_debug(DRIVER_NAME ": " fmt , ## args)
303
304 #ifndef DEBUG
305 #undef VERBOSE_DEBUG
306 #undef DUMP_MSGS
307 #endif /* !DEBUG */
308
309 #ifdef VERBOSE_DEBUG
310 #define VLDBG   LDBG
311 #else
312 #define VLDBG(lun,fmt,args...) \
313         do { } while (0)
314 #endif /* VERBOSE_DEBUG */
315
316 #define LERROR(lun,fmt,args...) \
317         dev_err(&(lun)->dev , fmt , ## args)
318 #define LWARN(lun,fmt,args...) \
319         dev_warn(&(lun)->dev , fmt , ## args)
320 #define LINFO(lun,fmt,args...) \
321         dev_info(&(lun)->dev , fmt , ## args)
322
323 #define MINFO(fmt,args...) \
324         pr_info(DRIVER_NAME ": " fmt , ## args)
325
326 #define DBG(d, fmt, args...) \
327         dev_dbg(&(d)->gadget->dev , fmt , ## args)
328 #define VDBG(d, fmt, args...) \
329         dev_vdbg(&(d)->gadget->dev , fmt , ## args)
330 #define ERROR(d, fmt, args...) \
331         dev_err(&(d)->gadget->dev , fmt , ## args)
332 #define WARNING(d, fmt, args...) \
333         dev_warn(&(d)->gadget->dev , fmt , ## args)
334 #define INFO(d, fmt, args...) \
335         dev_info(&(d)->gadget->dev , fmt , ## args)
336
337
338 /*-------------------------------------------------------------------------*/
339
340 /* Encapsulate the module parameter settings */
341
342 #define MAX_LUNS        8
343
344 static struct {
345         char            *file[MAX_LUNS];
346         int             ro[MAX_LUNS];
347         unsigned int    num_filenames;
348         unsigned int    num_ros;
349         unsigned int    nluns;
350
351         int             removable;
352         int             can_stall;
353         int             cdrom;
354
355         char            *transport_parm;
356         char            *protocol_parm;
357         unsigned short  vendor;
358         unsigned short  product;
359         unsigned short  release;
360         unsigned int    buflen;
361
362         int             transport_type;
363         char            *transport_name;
364         int             protocol_type;
365         char            *protocol_name;
366
367 } mod_data = {                                  // Default values
368         .transport_parm         = "BBB",
369         .protocol_parm          = "SCSI",
370         .removable              = 0,
371         .can_stall              = 1,
372         .cdrom                  = 0,
373         .vendor                 = DRIVER_VENDOR_ID,
374         .product                = DRIVER_PRODUCT_ID,
375         .release                = 0xffff,       // Use controller chip type
376         .buflen                 = 16384,
377         };
378
379
380 module_param_array_named(file, mod_data.file, charp, &mod_data.num_filenames,
381                 S_IRUGO);
382 MODULE_PARM_DESC(file, "names of backing files or devices");
383
384 module_param_array_named(ro, mod_data.ro, bool, &mod_data.num_ros, S_IRUGO);
385 MODULE_PARM_DESC(ro, "true to force read-only");
386
387 module_param_named(luns, mod_data.nluns, uint, S_IRUGO);
388 MODULE_PARM_DESC(luns, "number of LUNs");
389
390 module_param_named(removable, mod_data.removable, bool, S_IRUGO);
391 MODULE_PARM_DESC(removable, "true to simulate removable media");
392
393 module_param_named(stall, mod_data.can_stall, bool, S_IRUGO);
394 MODULE_PARM_DESC(stall, "false to prevent bulk stalls");
395
396 module_param_named(cdrom, mod_data.cdrom, bool, S_IRUGO);
397 MODULE_PARM_DESC(cdrom, "true to emulate cdrom instead of disk");
398
399
400 /* In the non-TEST version, only the module parameters listed above
401  * are available. */
402 #ifdef CONFIG_USB_FILE_STORAGE_TEST
403
404 module_param_named(transport, mod_data.transport_parm, charp, S_IRUGO);
405 MODULE_PARM_DESC(transport, "type of transport (BBB, CBI, or CB)");
406
407 module_param_named(protocol, mod_data.protocol_parm, charp, S_IRUGO);
408 MODULE_PARM_DESC(protocol, "type of protocol (RBC, 8020, QIC, UFI, "
409                 "8070, or SCSI)");
410
411 module_param_named(vendor, mod_data.vendor, ushort, S_IRUGO);
412 MODULE_PARM_DESC(vendor, "USB Vendor ID");
413
414 module_param_named(product, mod_data.product, ushort, S_IRUGO);
415 MODULE_PARM_DESC(product, "USB Product ID");
416
417 module_param_named(release, mod_data.release, ushort, S_IRUGO);
418 MODULE_PARM_DESC(release, "USB release number");
419
420 module_param_named(buflen, mod_data.buflen, uint, S_IRUGO);
421 MODULE_PARM_DESC(buflen, "I/O buffer size");
422
423 #endif /* CONFIG_USB_FILE_STORAGE_TEST */
424
425
426 /*-------------------------------------------------------------------------*/
427
428 /* SCSI device types */
429 #define TYPE_DISK       0x00
430 #define TYPE_CDROM      0x05
431
432 /* USB protocol value = the transport method */
433 #define USB_PR_CBI      0x00            // Control/Bulk/Interrupt
434 #define USB_PR_CB       0x01            // Control/Bulk w/o interrupt
435 #define USB_PR_BULK     0x50            // Bulk-only
436
437 /* USB subclass value = the protocol encapsulation */
438 #define USB_SC_RBC      0x01            // Reduced Block Commands (flash)
439 #define USB_SC_8020     0x02            // SFF-8020i, MMC-2, ATAPI (CD-ROM)
440 #define USB_SC_QIC      0x03            // QIC-157 (tape)
441 #define USB_SC_UFI      0x04            // UFI (floppy)
442 #define USB_SC_8070     0x05            // SFF-8070i (removable)
443 #define USB_SC_SCSI     0x06            // Transparent SCSI
444
445 /* Bulk-only data structures */
446
447 /* Command Block Wrapper */
448 struct bulk_cb_wrap {
449         __le32  Signature;              // Contains 'USBC'
450         u32     Tag;                    // Unique per command id
451         __le32  DataTransferLength;     // Size of the data
452         u8      Flags;                  // Direction in bit 7
453         u8      Lun;                    // LUN (normally 0)
454         u8      Length;                 // Of the CDB, <= MAX_COMMAND_SIZE
455         u8      CDB[16];                // Command Data Block
456 };
457
458 #define USB_BULK_CB_WRAP_LEN    31
459 #define USB_BULK_CB_SIG         0x43425355      // Spells out USBC
460 #define USB_BULK_IN_FLAG        0x80
461
462 /* Command Status Wrapper */
463 struct bulk_cs_wrap {
464         __le32  Signature;              // Should = 'USBS'
465         u32     Tag;                    // Same as original command
466         __le32  Residue;                // Amount not transferred
467         u8      Status;                 // See below
468 };
469
470 #define USB_BULK_CS_WRAP_LEN    13
471 #define USB_BULK_CS_SIG         0x53425355      // Spells out 'USBS'
472 #define USB_STATUS_PASS         0
473 #define USB_STATUS_FAIL         1
474 #define USB_STATUS_PHASE_ERROR  2
475
476 /* Bulk-only class specific requests */
477 #define USB_BULK_RESET_REQUEST          0xff
478 #define USB_BULK_GET_MAX_LUN_REQUEST    0xfe
479
480
481 /* CBI Interrupt data structure */
482 struct interrupt_data {
483         u8      bType;
484         u8      bValue;
485 };
486
487 #define CBI_INTERRUPT_DATA_LEN          2
488
489 /* CBI Accept Device-Specific Command request */
490 #define USB_CBI_ADSC_REQUEST            0x00
491
492
493 #define MAX_COMMAND_SIZE        16      // Length of a SCSI Command Data Block
494
495 /* SCSI commands that we recognize */
496 #define SC_FORMAT_UNIT                  0x04
497 #define SC_INQUIRY                      0x12
498 #define SC_MODE_SELECT_6                0x15
499 #define SC_MODE_SELECT_10               0x55
500 #define SC_MODE_SENSE_6                 0x1a
501 #define SC_MODE_SENSE_10                0x5a
502 #define SC_PREVENT_ALLOW_MEDIUM_REMOVAL 0x1e
503 #define SC_READ_6                       0x08
504 #define SC_READ_10                      0x28
505 #define SC_READ_12                      0xa8
506 #define SC_READ_CAPACITY                0x25
507 #define SC_READ_FORMAT_CAPACITIES       0x23
508 #define SC_READ_HEADER                  0x44
509 #define SC_READ_TOC                     0x43
510 #define SC_RELEASE                      0x17
511 #define SC_REQUEST_SENSE                0x03
512 #define SC_RESERVE                      0x16
513 #define SC_SEND_DIAGNOSTIC              0x1d
514 #define SC_START_STOP_UNIT              0x1b
515 #define SC_SYNCHRONIZE_CACHE            0x35
516 #define SC_TEST_UNIT_READY              0x00
517 #define SC_VERIFY                       0x2f
518 #define SC_WRITE_6                      0x0a
519 #define SC_WRITE_10                     0x2a
520 #define SC_WRITE_12                     0xaa
521
522 /* SCSI Sense Key/Additional Sense Code/ASC Qualifier values */
523 #define SS_NO_SENSE                             0
524 #define SS_COMMUNICATION_FAILURE                0x040800
525 #define SS_INVALID_COMMAND                      0x052000
526 #define SS_INVALID_FIELD_IN_CDB                 0x052400
527 #define SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE   0x052100
528 #define SS_LOGICAL_UNIT_NOT_SUPPORTED           0x052500
529 #define SS_MEDIUM_NOT_PRESENT                   0x023a00
530 #define SS_MEDIUM_REMOVAL_PREVENTED             0x055302
531 #define SS_NOT_READY_TO_READY_TRANSITION        0x062800
532 #define SS_RESET_OCCURRED                       0x062900
533 #define SS_SAVING_PARAMETERS_NOT_SUPPORTED      0x053900
534 #define SS_UNRECOVERED_READ_ERROR               0x031100
535 #define SS_WRITE_ERROR                          0x030c02
536 #define SS_WRITE_PROTECTED                      0x072700
537
538 #define SK(x)           ((u8) ((x) >> 16))      // Sense Key byte, etc.
539 #define ASC(x)          ((u8) ((x) >> 8))
540 #define ASCQ(x)         ((u8) (x))
541
542
543 /*-------------------------------------------------------------------------*/
544
545 /*
546  * These definitions will permit the compiler to avoid generating code for
547  * parts of the driver that aren't used in the non-TEST version.  Even gcc
548  * can recognize when a test of a constant expression yields a dead code
549  * path.
550  */
551
552 #ifdef CONFIG_USB_FILE_STORAGE_TEST
553
554 #define transport_is_bbb()      (mod_data.transport_type == USB_PR_BULK)
555 #define transport_is_cbi()      (mod_data.transport_type == USB_PR_CBI)
556 #define protocol_is_scsi()      (mod_data.protocol_type == USB_SC_SCSI)
557
558 #else
559
560 #define transport_is_bbb()      1
561 #define transport_is_cbi()      0
562 #define protocol_is_scsi()      1
563
564 #endif /* CONFIG_USB_FILE_STORAGE_TEST */
565
566
567 struct lun {
568         struct file     *filp;
569         loff_t          file_length;
570         loff_t          num_sectors;
571
572         unsigned int    ro : 1;
573         unsigned int    prevent_medium_removal : 1;
574         unsigned int    registered : 1;
575         unsigned int    info_valid : 1;
576
577         u32             sense_data;
578         u32             sense_data_info;
579         u32             unit_attention_data;
580
581         struct device   dev;
582 };
583
584 #define backing_file_is_open(curlun)    ((curlun)->filp != NULL)
585
586 static struct lun *dev_to_lun(struct device *dev)
587 {
588         return container_of(dev, struct lun, dev);
589 }
590
591
592 /* Big enough to hold our biggest descriptor */
593 #define EP0_BUFSIZE     256
594 #define DELAYED_STATUS  (EP0_BUFSIZE + 999)     // An impossibly large value
595
596 /* Number of buffers we will use.  2 is enough for double-buffering */
597 #define NUM_BUFFERS     2
598
599 enum fsg_buffer_state {
600         BUF_STATE_EMPTY = 0,
601         BUF_STATE_FULL,
602         BUF_STATE_BUSY
603 };
604
605 struct fsg_buffhd {
606         void                            *buf;
607         enum fsg_buffer_state           state;
608         struct fsg_buffhd               *next;
609
610         /* The NetChip 2280 is faster, and handles some protocol faults
611          * better, if we don't submit any short bulk-out read requests.
612          * So we will record the intended request length here. */
613         unsigned int                    bulk_out_intended_length;
614
615         struct usb_request              *inreq;
616         int                             inreq_busy;
617         struct usb_request              *outreq;
618         int                             outreq_busy;
619 };
620
621 enum fsg_state {
622         FSG_STATE_COMMAND_PHASE = -10,          // This one isn't used anywhere
623         FSG_STATE_DATA_PHASE,
624         FSG_STATE_STATUS_PHASE,
625
626         FSG_STATE_IDLE = 0,
627         FSG_STATE_ABORT_BULK_OUT,
628         FSG_STATE_RESET,
629         FSG_STATE_INTERFACE_CHANGE,
630         FSG_STATE_CONFIG_CHANGE,
631         FSG_STATE_DISCONNECT,
632         FSG_STATE_EXIT,
633         FSG_STATE_TERMINATED
634 };
635
636 enum data_direction {
637         DATA_DIR_UNKNOWN = 0,
638         DATA_DIR_FROM_HOST,
639         DATA_DIR_TO_HOST,
640         DATA_DIR_NONE
641 };
642
643 struct fsg_dev {
644         /* lock protects: state, all the req_busy's, and cbbuf_cmnd */
645         spinlock_t              lock;
646         struct usb_gadget       *gadget;
647
648         /* filesem protects: backing files in use */
649         struct rw_semaphore     filesem;
650
651         /* reference counting: wait until all LUNs are released */
652         struct kref             ref;
653
654         struct usb_ep           *ep0;           // Handy copy of gadget->ep0
655         struct usb_request      *ep0req;        // For control responses
656         unsigned int            ep0_req_tag;
657         const char              *ep0req_name;
658
659         struct usb_request      *intreq;        // For interrupt responses
660         int                     intreq_busy;
661         struct fsg_buffhd       *intr_buffhd;
662
663         unsigned int            bulk_out_maxpacket;
664         enum fsg_state          state;          // For exception handling
665         unsigned int            exception_req_tag;
666
667         u8                      config, new_config;
668
669         unsigned int            running : 1;
670         unsigned int            bulk_in_enabled : 1;
671         unsigned int            bulk_out_enabled : 1;
672         unsigned int            intr_in_enabled : 1;
673         unsigned int            phase_error : 1;
674         unsigned int            short_packet_received : 1;
675         unsigned int            bad_lun_okay : 1;
676
677         unsigned long           atomic_bitflags;
678 #define REGISTERED              0
679 #define IGNORE_BULK_OUT         1
680 #define SUSPENDED               2
681
682         struct usb_ep           *bulk_in;
683         struct usb_ep           *bulk_out;
684         struct usb_ep           *intr_in;
685
686         struct fsg_buffhd       *next_buffhd_to_fill;
687         struct fsg_buffhd       *next_buffhd_to_drain;
688         struct fsg_buffhd       buffhds[NUM_BUFFERS];
689
690         int                     thread_wakeup_needed;
691         struct completion       thread_notifier;
692         struct task_struct      *thread_task;
693
694         int                     cmnd_size;
695         u8                      cmnd[MAX_COMMAND_SIZE];
696         enum data_direction     data_dir;
697         u32                     data_size;
698         u32                     data_size_from_cmnd;
699         u32                     tag;
700         unsigned int            lun;
701         u32                     residue;
702         u32                     usb_amount_left;
703
704         /* The CB protocol offers no way for a host to know when a command
705          * has completed.  As a result the next command may arrive early,
706          * and we will still have to handle it.  For that reason we need
707          * a buffer to store new commands when using CB (or CBI, which
708          * does not oblige a host to wait for command completion either). */
709         int                     cbbuf_cmnd_size;
710         u8                      cbbuf_cmnd[MAX_COMMAND_SIZE];
711
712         unsigned int            nluns;
713         struct lun              *luns;
714         struct lun              *curlun;
715 };
716
717 typedef void (*fsg_routine_t)(struct fsg_dev *);
718
719 static int exception_in_progress(struct fsg_dev *fsg)
720 {
721         return (fsg->state > FSG_STATE_IDLE);
722 }
723
724 /* Make bulk-out requests be divisible by the maxpacket size */
725 static void set_bulk_out_req_length(struct fsg_dev *fsg,
726                 struct fsg_buffhd *bh, unsigned int length)
727 {
728         unsigned int    rem;
729
730         bh->bulk_out_intended_length = length;
731         rem = length % fsg->bulk_out_maxpacket;
732         if (rem > 0)
733                 length += fsg->bulk_out_maxpacket - rem;
734         bh->outreq->length = length;
735 }
736
737 static struct fsg_dev                   *the_fsg;
738 static struct usb_gadget_driver         fsg_driver;
739
740 static void     close_backing_file(struct lun *curlun);
741 static void     close_all_backing_files(struct fsg_dev *fsg);
742
743
744 /*-------------------------------------------------------------------------*/
745
746 #ifdef DUMP_MSGS
747
748 static void dump_msg(struct fsg_dev *fsg, const char *label,
749                 const u8 *buf, unsigned int length)
750 {
751         if (length < 512) {
752                 DBG(fsg, "%s, length %u:\n", label, length);
753                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET,
754                                 16, 1, buf, length, 0);
755         }
756 }
757
758 static void dump_cdb(struct fsg_dev *fsg)
759 {}
760
761 #else
762
763 static void dump_msg(struct fsg_dev *fsg, const char *label,
764                 const u8 *buf, unsigned int length)
765 {}
766
767 #ifdef VERBOSE_DEBUG
768
769 static void dump_cdb(struct fsg_dev *fsg)
770 {
771         print_hex_dump(KERN_DEBUG, "SCSI CDB: ", DUMP_PREFIX_NONE,
772                         16, 1, fsg->cmnd, fsg->cmnd_size, 0);
773 }
774
775 #else
776
777 static void dump_cdb(struct fsg_dev *fsg)
778 {}
779
780 #endif /* VERBOSE_DEBUG */
781 #endif /* DUMP_MSGS */
782
783
784 static int fsg_set_halt(struct fsg_dev *fsg, struct usb_ep *ep)
785 {
786         const char      *name;
787
788         if (ep == fsg->bulk_in)
789                 name = "bulk-in";
790         else if (ep == fsg->bulk_out)
791                 name = "bulk-out";
792         else
793                 name = ep->name;
794         DBG(fsg, "%s set halt\n", name);
795         return usb_ep_set_halt(ep);
796 }
797
798
799 /*-------------------------------------------------------------------------*/
800
801 /* Routines for unaligned data access */
802
803 static u16 get_be16(u8 *buf)
804 {
805         return ((u16) buf[0] << 8) | ((u16) buf[1]);
806 }
807
808 static u32 get_be32(u8 *buf)
809 {
810         return ((u32) buf[0] << 24) | ((u32) buf[1] << 16) |
811                         ((u32) buf[2] << 8) | ((u32) buf[3]);
812 }
813
814 static void put_be16(u8 *buf, u16 val)
815 {
816         buf[0] = val >> 8;
817         buf[1] = val;
818 }
819
820 static void put_be32(u8 *buf, u32 val)
821 {
822         buf[0] = val >> 24;
823         buf[1] = val >> 16;
824         buf[2] = val >> 8;
825         buf[3] = val & 0xff;
826 }
827
828
829 /*-------------------------------------------------------------------------*/
830
831 /*
832  * DESCRIPTORS ... most are static, but strings and (full) configuration
833  * descriptors are built on demand.  Also the (static) config and interface
834  * descriptors are adjusted during fsg_bind().
835  */
836 #define STRING_MANUFACTURER     1
837 #define STRING_PRODUCT          2
838 #define STRING_SERIAL           3
839 #define STRING_CONFIG           4
840 #define STRING_INTERFACE        5
841
842 /* There is only one configuration. */
843 #define CONFIG_VALUE            1
844
845 static struct usb_device_descriptor
846 device_desc = {
847         .bLength =              sizeof device_desc,
848         .bDescriptorType =      USB_DT_DEVICE,
849
850         .bcdUSB =               cpu_to_le16(0x0200),
851         .bDeviceClass =         USB_CLASS_PER_INTERFACE,
852
853         /* The next three values can be overridden by module parameters */
854         .idVendor =             cpu_to_le16(DRIVER_VENDOR_ID),
855         .idProduct =            cpu_to_le16(DRIVER_PRODUCT_ID),
856         .bcdDevice =            cpu_to_le16(0xffff),
857
858         .iManufacturer =        STRING_MANUFACTURER,
859         .iProduct =             STRING_PRODUCT,
860         .iSerialNumber =        STRING_SERIAL,
861         .bNumConfigurations =   1,
862 };
863
864 static struct usb_config_descriptor
865 config_desc = {
866         .bLength =              sizeof config_desc,
867         .bDescriptorType =      USB_DT_CONFIG,
868
869         /* wTotalLength computed by usb_gadget_config_buf() */
870         .bNumInterfaces =       1,
871         .bConfigurationValue =  CONFIG_VALUE,
872         .iConfiguration =       STRING_CONFIG,
873         .bmAttributes =         USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
874         .bMaxPower =            CONFIG_USB_GADGET_VBUS_DRAW / 2,
875 };
876
877 static struct usb_otg_descriptor
878 otg_desc = {
879         .bLength =              sizeof(otg_desc),
880         .bDescriptorType =      USB_DT_OTG,
881
882         .bmAttributes =         USB_OTG_SRP,
883 };
884
885 /* There is only one interface. */
886
887 static struct usb_interface_descriptor
888 intf_desc = {
889         .bLength =              sizeof intf_desc,
890         .bDescriptorType =      USB_DT_INTERFACE,
891
892         .bNumEndpoints =        2,              // Adjusted during fsg_bind()
893         .bInterfaceClass =      USB_CLASS_MASS_STORAGE,
894         .bInterfaceSubClass =   USB_SC_SCSI,    // Adjusted during fsg_bind()
895         .bInterfaceProtocol =   USB_PR_BULK,    // Adjusted during fsg_bind()
896         .iInterface =           STRING_INTERFACE,
897 };
898
899 /* Three full-speed endpoint descriptors: bulk-in, bulk-out,
900  * and interrupt-in. */
901
902 static struct usb_endpoint_descriptor
903 fs_bulk_in_desc = {
904         .bLength =              USB_DT_ENDPOINT_SIZE,
905         .bDescriptorType =      USB_DT_ENDPOINT,
906
907         .bEndpointAddress =     USB_DIR_IN,
908         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
909         /* wMaxPacketSize set by autoconfiguration */
910 };
911
912 static struct usb_endpoint_descriptor
913 fs_bulk_out_desc = {
914         .bLength =              USB_DT_ENDPOINT_SIZE,
915         .bDescriptorType =      USB_DT_ENDPOINT,
916
917         .bEndpointAddress =     USB_DIR_OUT,
918         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
919         /* wMaxPacketSize set by autoconfiguration */
920 };
921
922 static struct usb_endpoint_descriptor
923 fs_intr_in_desc = {
924         .bLength =              USB_DT_ENDPOINT_SIZE,
925         .bDescriptorType =      USB_DT_ENDPOINT,
926
927         .bEndpointAddress =     USB_DIR_IN,
928         .bmAttributes =         USB_ENDPOINT_XFER_INT,
929         .wMaxPacketSize =       cpu_to_le16(2),
930         .bInterval =            32,     // frames -> 32 ms
931 };
932
933 static const struct usb_descriptor_header *fs_function[] = {
934         (struct usb_descriptor_header *) &otg_desc,
935         (struct usb_descriptor_header *) &intf_desc,
936         (struct usb_descriptor_header *) &fs_bulk_in_desc,
937         (struct usb_descriptor_header *) &fs_bulk_out_desc,
938         (struct usb_descriptor_header *) &fs_intr_in_desc,
939         NULL,
940 };
941 #define FS_FUNCTION_PRE_EP_ENTRIES      2
942
943
944 /*
945  * USB 2.0 devices need to expose both high speed and full speed
946  * descriptors, unless they only run at full speed.
947  *
948  * That means alternate endpoint descriptors (bigger packets)
949  * and a "device qualifier" ... plus more construction options
950  * for the config descriptor.
951  */
952 static struct usb_qualifier_descriptor
953 dev_qualifier = {
954         .bLength =              sizeof dev_qualifier,
955         .bDescriptorType =      USB_DT_DEVICE_QUALIFIER,
956
957         .bcdUSB =               cpu_to_le16(0x0200),
958         .bDeviceClass =         USB_CLASS_PER_INTERFACE,
959
960         .bNumConfigurations =   1,
961 };
962
963 static struct usb_endpoint_descriptor
964 hs_bulk_in_desc = {
965         .bLength =              USB_DT_ENDPOINT_SIZE,
966         .bDescriptorType =      USB_DT_ENDPOINT,
967
968         /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
969         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
970         .wMaxPacketSize =       cpu_to_le16(512),
971 };
972
973 static struct usb_endpoint_descriptor
974 hs_bulk_out_desc = {
975         .bLength =              USB_DT_ENDPOINT_SIZE,
976         .bDescriptorType =      USB_DT_ENDPOINT,
977
978         /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
979         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
980         .wMaxPacketSize =       cpu_to_le16(512),
981         .bInterval =            1,      // NAK every 1 uframe
982 };
983
984 static struct usb_endpoint_descriptor
985 hs_intr_in_desc = {
986         .bLength =              USB_DT_ENDPOINT_SIZE,
987         .bDescriptorType =      USB_DT_ENDPOINT,
988
989         /* bEndpointAddress copied from fs_intr_in_desc during fsg_bind() */
990         .bmAttributes =         USB_ENDPOINT_XFER_INT,
991         .wMaxPacketSize =       cpu_to_le16(2),
992         .bInterval =            9,      // 2**(9-1) = 256 uframes -> 32 ms
993 };
994
995 static const struct usb_descriptor_header *hs_function[] = {
996         (struct usb_descriptor_header *) &otg_desc,
997         (struct usb_descriptor_header *) &intf_desc,
998         (struct usb_descriptor_header *) &hs_bulk_in_desc,
999         (struct usb_descriptor_header *) &hs_bulk_out_desc,
1000         (struct usb_descriptor_header *) &hs_intr_in_desc,
1001         NULL,
1002 };
1003 #define HS_FUNCTION_PRE_EP_ENTRIES      2
1004
1005 /* Maxpacket and other transfer characteristics vary by speed. */
1006 static struct usb_endpoint_descriptor *
1007 ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *fs,
1008                 struct usb_endpoint_descriptor *hs)
1009 {
1010         if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
1011                 return hs;
1012         return fs;
1013 }
1014
1015
1016 /* The CBI specification limits the serial string to 12 uppercase hexadecimal
1017  * characters. */
1018 static char                             manufacturer[64];
1019 static char                             serial[13];
1020
1021 /* Static strings, in UTF-8 (for simplicity we use only ASCII characters) */
1022 static struct usb_string                strings[] = {
1023         {STRING_MANUFACTURER,   manufacturer},
1024         {STRING_PRODUCT,        longname},
1025         {STRING_SERIAL,         serial},
1026         {STRING_CONFIG,         "Self-powered"},
1027         {STRING_INTERFACE,      "Mass Storage"},
1028         {}
1029 };
1030
1031 static struct usb_gadget_strings        stringtab = {
1032         .language       = 0x0409,               // en-us
1033         .strings        = strings,
1034 };
1035
1036
1037 /*
1038  * Config descriptors must agree with the code that sets configurations
1039  * and with code managing interfaces and their altsettings.  They must
1040  * also handle different speeds and other-speed requests.
1041  */
1042 static int populate_config_buf(struct usb_gadget *gadget,
1043                 u8 *buf, u8 type, unsigned index)
1044 {
1045         enum usb_device_speed                   speed = gadget->speed;
1046         int                                     len;
1047         const struct usb_descriptor_header      **function;
1048
1049         if (index > 0)
1050                 return -EINVAL;
1051
1052         if (gadget_is_dualspeed(gadget) && type == USB_DT_OTHER_SPEED_CONFIG)
1053                 speed = (USB_SPEED_FULL + USB_SPEED_HIGH) - speed;
1054         if (gadget_is_dualspeed(gadget) && speed == USB_SPEED_HIGH)
1055                 function = hs_function;
1056         else
1057                 function = fs_function;
1058
1059         /* for now, don't advertise srp-only devices */
1060         if (!gadget_is_otg(gadget))
1061                 function++;
1062
1063         len = usb_gadget_config_buf(&config_desc, buf, EP0_BUFSIZE, function);
1064         ((struct usb_config_descriptor *) buf)->bDescriptorType = type;
1065         return len;
1066 }
1067
1068
1069 /*-------------------------------------------------------------------------*/
1070
1071 /* These routines may be called in process context or in_irq */
1072
1073 /* Caller must hold fsg->lock */
1074 static void wakeup_thread(struct fsg_dev *fsg)
1075 {
1076         /* Tell the main thread that something has happened */
1077         fsg->thread_wakeup_needed = 1;
1078         if (fsg->thread_task)
1079                 wake_up_process(fsg->thread_task);
1080 }
1081
1082
1083 static void raise_exception(struct fsg_dev *fsg, enum fsg_state new_state)
1084 {
1085         unsigned long           flags;
1086
1087         /* Do nothing if a higher-priority exception is already in progress.
1088          * If a lower-or-equal priority exception is in progress, preempt it
1089          * and notify the main thread by sending it a signal. */
1090         spin_lock_irqsave(&fsg->lock, flags);
1091         if (fsg->state <= new_state) {
1092                 fsg->exception_req_tag = fsg->ep0_req_tag;
1093                 fsg->state = new_state;
1094                 if (fsg->thread_task)
1095                         send_sig_info(SIGUSR1, SEND_SIG_FORCED,
1096                                         fsg->thread_task);
1097         }
1098         spin_unlock_irqrestore(&fsg->lock, flags);
1099 }
1100
1101
1102 /*-------------------------------------------------------------------------*/
1103
1104 /* The disconnect callback and ep0 routines.  These always run in_irq,
1105  * except that ep0_queue() is called in the main thread to acknowledge
1106  * completion of various requests: set config, set interface, and
1107  * Bulk-only device reset. */
1108
1109 static void fsg_disconnect(struct usb_gadget *gadget)
1110 {
1111         struct fsg_dev          *fsg = get_gadget_data(gadget);
1112
1113         DBG(fsg, "disconnect or port reset\n");
1114         raise_exception(fsg, FSG_STATE_DISCONNECT);
1115 }
1116
1117
1118 static int ep0_queue(struct fsg_dev *fsg)
1119 {
1120         int     rc;
1121
1122         rc = usb_ep_queue(fsg->ep0, fsg->ep0req, GFP_ATOMIC);
1123         if (rc != 0 && rc != -ESHUTDOWN) {
1124
1125                 /* We can't do much more than wait for a reset */
1126                 WARNING(fsg, "error in submission: %s --> %d\n",
1127                                 fsg->ep0->name, rc);
1128         }
1129         return rc;
1130 }
1131
1132 static void ep0_complete(struct usb_ep *ep, struct usb_request *req)
1133 {
1134         struct fsg_dev          *fsg = ep->driver_data;
1135
1136         if (req->actual > 0)
1137                 dump_msg(fsg, fsg->ep0req_name, req->buf, req->actual);
1138         if (req->status || req->actual != req->length)
1139                 DBG(fsg, "%s --> %d, %u/%u\n", __func__,
1140                                 req->status, req->actual, req->length);
1141         if (req->status == -ECONNRESET)         // Request was cancelled
1142                 usb_ep_fifo_flush(ep);
1143
1144         if (req->status == 0 && req->context)
1145                 ((fsg_routine_t) (req->context))(fsg);
1146 }
1147
1148
1149 /*-------------------------------------------------------------------------*/
1150
1151 /* Bulk and interrupt endpoint completion handlers.
1152  * These always run in_irq. */
1153
1154 static void bulk_in_complete(struct usb_ep *ep, struct usb_request *req)
1155 {
1156         struct fsg_dev          *fsg = ep->driver_data;
1157         struct fsg_buffhd       *bh = req->context;
1158
1159         if (req->status || req->actual != req->length)
1160                 DBG(fsg, "%s --> %d, %u/%u\n", __func__,
1161                                 req->status, req->actual, req->length);
1162         if (req->status == -ECONNRESET)         // Request was cancelled
1163                 usb_ep_fifo_flush(ep);
1164
1165         /* Hold the lock while we update the request and buffer states */
1166         smp_wmb();
1167         spin_lock(&fsg->lock);
1168         bh->inreq_busy = 0;
1169         bh->state = BUF_STATE_EMPTY;
1170         wakeup_thread(fsg);
1171         spin_unlock(&fsg->lock);
1172 }
1173
1174 static void bulk_out_complete(struct usb_ep *ep, struct usb_request *req)
1175 {
1176         struct fsg_dev          *fsg = ep->driver_data;
1177         struct fsg_buffhd       *bh = req->context;
1178
1179         dump_msg(fsg, "bulk-out", req->buf, req->actual);
1180         if (req->status || req->actual != bh->bulk_out_intended_length)
1181                 DBG(fsg, "%s --> %d, %u/%u\n", __func__,
1182                                 req->status, req->actual,
1183                                 bh->bulk_out_intended_length);
1184         if (req->status == -ECONNRESET)         // Request was cancelled
1185                 usb_ep_fifo_flush(ep);
1186
1187         /* Hold the lock while we update the request and buffer states */
1188         smp_wmb();
1189         spin_lock(&fsg->lock);
1190         bh->outreq_busy = 0;
1191         bh->state = BUF_STATE_FULL;
1192         wakeup_thread(fsg);
1193         spin_unlock(&fsg->lock);
1194 }
1195
1196
1197 #ifdef CONFIG_USB_FILE_STORAGE_TEST
1198 static void intr_in_complete(struct usb_ep *ep, struct usb_request *req)
1199 {
1200         struct fsg_dev          *fsg = ep->driver_data;
1201         struct fsg_buffhd       *bh = req->context;
1202
1203         if (req->status || req->actual != req->length)
1204                 DBG(fsg, "%s --> %d, %u/%u\n", __func__,
1205                                 req->status, req->actual, req->length);
1206         if (req->status == -ECONNRESET)         // Request was cancelled
1207                 usb_ep_fifo_flush(ep);
1208
1209         /* Hold the lock while we update the request and buffer states */
1210         smp_wmb();
1211         spin_lock(&fsg->lock);
1212         fsg->intreq_busy = 0;
1213         bh->state = BUF_STATE_EMPTY;
1214         wakeup_thread(fsg);
1215         spin_unlock(&fsg->lock);
1216 }
1217
1218 #else
1219 static void intr_in_complete(struct usb_ep *ep, struct usb_request *req)
1220 {}
1221 #endif /* CONFIG_USB_FILE_STORAGE_TEST */
1222
1223
1224 /*-------------------------------------------------------------------------*/
1225
1226 /* Ep0 class-specific handlers.  These always run in_irq. */
1227
1228 #ifdef CONFIG_USB_FILE_STORAGE_TEST
1229 static void received_cbi_adsc(struct fsg_dev *fsg, struct fsg_buffhd *bh)
1230 {
1231         struct usb_request      *req = fsg->ep0req;
1232         static u8               cbi_reset_cmnd[6] = {
1233                         SC_SEND_DIAGNOSTIC, 4, 0xff, 0xff, 0xff, 0xff};
1234
1235         /* Error in command transfer? */
1236         if (req->status || req->length != req->actual ||
1237                         req->actual < 6 || req->actual > MAX_COMMAND_SIZE) {
1238
1239                 /* Not all controllers allow a protocol stall after
1240                  * receiving control-out data, but we'll try anyway. */
1241                 fsg_set_halt(fsg, fsg->ep0);
1242                 return;                 // Wait for reset
1243         }
1244
1245         /* Is it the special reset command? */
1246         if (req->actual >= sizeof cbi_reset_cmnd &&
1247                         memcmp(req->buf, cbi_reset_cmnd,
1248                                 sizeof cbi_reset_cmnd) == 0) {
1249
1250                 /* Raise an exception to stop the current operation
1251                  * and reinitialize our state. */
1252                 DBG(fsg, "cbi reset request\n");
1253                 raise_exception(fsg, FSG_STATE_RESET);
1254                 return;
1255         }
1256
1257         VDBG(fsg, "CB[I] accept device-specific command\n");
1258         spin_lock(&fsg->lock);
1259
1260         /* Save the command for later */
1261         if (fsg->cbbuf_cmnd_size)
1262                 WARNING(fsg, "CB[I] overwriting previous command\n");
1263         fsg->cbbuf_cmnd_size = req->actual;
1264         memcpy(fsg->cbbuf_cmnd, req->buf, fsg->cbbuf_cmnd_size);
1265
1266         wakeup_thread(fsg);
1267         spin_unlock(&fsg->lock);
1268 }
1269
1270 #else
1271 static void received_cbi_adsc(struct fsg_dev *fsg, struct fsg_buffhd *bh)
1272 {}
1273 #endif /* CONFIG_USB_FILE_STORAGE_TEST */
1274
1275
1276 static int class_setup_req(struct fsg_dev *fsg,
1277                 const struct usb_ctrlrequest *ctrl)
1278 {
1279         struct usb_request      *req = fsg->ep0req;
1280         int                     value = -EOPNOTSUPP;
1281         u16                     w_index = le16_to_cpu(ctrl->wIndex);
1282         u16                     w_value = le16_to_cpu(ctrl->wValue);
1283         u16                     w_length = le16_to_cpu(ctrl->wLength);
1284
1285         if (!fsg->config)
1286                 return value;
1287
1288         /* Handle Bulk-only class-specific requests */
1289         if (transport_is_bbb()) {
1290                 switch (ctrl->bRequest) {
1291
1292                 case USB_BULK_RESET_REQUEST:
1293                         if (ctrl->bRequestType != (USB_DIR_OUT |
1294                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE))
1295                                 break;
1296                         if (w_index != 0 || w_value != 0) {
1297                                 value = -EDOM;
1298                                 break;
1299                         }
1300
1301                         /* Raise an exception to stop the current operation
1302                          * and reinitialize our state. */
1303                         DBG(fsg, "bulk reset request\n");
1304                         raise_exception(fsg, FSG_STATE_RESET);
1305                         value = DELAYED_STATUS;
1306                         break;
1307
1308                 case USB_BULK_GET_MAX_LUN_REQUEST:
1309                         if (ctrl->bRequestType != (USB_DIR_IN |
1310                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE))
1311                                 break;
1312                         if (w_index != 0 || w_value != 0) {
1313                                 value = -EDOM;
1314                                 break;
1315                         }
1316                         VDBG(fsg, "get max LUN\n");
1317                         *(u8 *) req->buf = fsg->nluns - 1;
1318                         value = 1;
1319                         break;
1320                 }
1321         }
1322
1323         /* Handle CBI class-specific requests */
1324         else {
1325                 switch (ctrl->bRequest) {
1326
1327                 case USB_CBI_ADSC_REQUEST:
1328                         if (ctrl->bRequestType != (USB_DIR_OUT |
1329                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE))
1330                                 break;
1331                         if (w_index != 0 || w_value != 0) {
1332                                 value = -EDOM;
1333                                 break;
1334                         }
1335                         if (w_length > MAX_COMMAND_SIZE) {
1336                                 value = -EOVERFLOW;
1337                                 break;
1338                         }
1339                         value = w_length;
1340                         fsg->ep0req->context = received_cbi_adsc;
1341                         break;
1342                 }
1343         }
1344
1345         if (value == -EOPNOTSUPP)
1346                 VDBG(fsg,
1347                         "unknown class-specific control req "
1348                         "%02x.%02x v%04x i%04x l%u\n",
1349                         ctrl->bRequestType, ctrl->bRequest,
1350                         le16_to_cpu(ctrl->wValue), w_index, w_length);
1351         return value;
1352 }
1353
1354
1355 /*-------------------------------------------------------------------------*/
1356
1357 /* Ep0 standard request handlers.  These always run in_irq. */
1358
1359 static int standard_setup_req(struct fsg_dev *fsg,
1360                 const struct usb_ctrlrequest *ctrl)
1361 {
1362         struct usb_request      *req = fsg->ep0req;
1363         int                     value = -EOPNOTSUPP;
1364         u16                     w_index = le16_to_cpu(ctrl->wIndex);
1365         u16                     w_value = le16_to_cpu(ctrl->wValue);
1366
1367         /* Usually this just stores reply data in the pre-allocated ep0 buffer,
1368          * but config change events will also reconfigure hardware. */
1369         switch (ctrl->bRequest) {
1370
1371         case USB_REQ_GET_DESCRIPTOR:
1372                 if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_STANDARD |
1373                                 USB_RECIP_DEVICE))
1374                         break;
1375                 switch (w_value >> 8) {
1376
1377                 case USB_DT_DEVICE:
1378                         VDBG(fsg, "get device descriptor\n");
1379                         value = sizeof device_desc;
1380                         memcpy(req->buf, &device_desc, value);
1381                         break;
1382                 case USB_DT_DEVICE_QUALIFIER:
1383                         VDBG(fsg, "get device qualifier\n");
1384                         if (!gadget_is_dualspeed(fsg->gadget))
1385                                 break;
1386                         value = sizeof dev_qualifier;
1387                         memcpy(req->buf, &dev_qualifier, value);
1388                         break;
1389
1390                 case USB_DT_OTHER_SPEED_CONFIG:
1391                         VDBG(fsg, "get other-speed config descriptor\n");
1392                         if (!gadget_is_dualspeed(fsg->gadget))
1393                                 break;
1394                         goto get_config;
1395                 case USB_DT_CONFIG:
1396                         VDBG(fsg, "get configuration descriptor\n");
1397 get_config:
1398                         value = populate_config_buf(fsg->gadget,
1399                                         req->buf,
1400                                         w_value >> 8,
1401                                         w_value & 0xff);
1402                         break;
1403
1404                 case USB_DT_STRING:
1405                         VDBG(fsg, "get string descriptor\n");
1406
1407                         /* wIndex == language code */
1408                         value = usb_gadget_get_string(&stringtab,
1409                                         w_value & 0xff, req->buf);
1410                         break;
1411                 }
1412                 break;
1413
1414         /* One config, two speeds */
1415         case USB_REQ_SET_CONFIGURATION:
1416                 if (ctrl->bRequestType != (USB_DIR_OUT | USB_TYPE_STANDARD |
1417                                 USB_RECIP_DEVICE))
1418                         break;
1419                 VDBG(fsg, "set configuration\n");
1420                 if (w_value == CONFIG_VALUE || w_value == 0) {
1421                         fsg->new_config = w_value;
1422
1423                         /* Raise an exception to wipe out previous transaction
1424                          * state (queued bufs, etc) and set the new config. */
1425                         raise_exception(fsg, FSG_STATE_CONFIG_CHANGE);
1426                         value = DELAYED_STATUS;
1427                 }
1428                 break;
1429         case USB_REQ_GET_CONFIGURATION:
1430                 if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_STANDARD |
1431                                 USB_RECIP_DEVICE))
1432                         break;
1433                 VDBG(fsg, "get configuration\n");
1434                 *(u8 *) req->buf = fsg->config;
1435                 value = 1;
1436                 break;
1437
1438         case USB_REQ_SET_INTERFACE:
1439                 if (ctrl->bRequestType != (USB_DIR_OUT| USB_TYPE_STANDARD |
1440                                 USB_RECIP_INTERFACE))
1441                         break;
1442                 if (fsg->config && w_index == 0) {
1443
1444                         /* Raise an exception to wipe out previous transaction
1445                          * state (queued bufs, etc) and install the new
1446                          * interface altsetting. */
1447                         raise_exception(fsg, FSG_STATE_INTERFACE_CHANGE);
1448                         value = DELAYED_STATUS;
1449                 }
1450                 break;
1451         case USB_REQ_GET_INTERFACE:
1452                 if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_STANDARD |
1453                                 USB_RECIP_INTERFACE))
1454                         break;
1455                 if (!fsg->config)
1456                         break;
1457                 if (w_index != 0) {
1458                         value = -EDOM;
1459                         break;
1460                 }
1461                 VDBG(fsg, "get interface\n");
1462                 *(u8 *) req->buf = 0;
1463                 value = 1;
1464                 break;
1465
1466         default:
1467                 VDBG(fsg,
1468                         "unknown control req %02x.%02x v%04x i%04x l%u\n",
1469                         ctrl->bRequestType, ctrl->bRequest,
1470                         w_value, w_index, le16_to_cpu(ctrl->wLength));
1471         }
1472
1473         return value;
1474 }
1475
1476
1477 static int fsg_setup(struct usb_gadget *gadget,
1478                 const struct usb_ctrlrequest *ctrl)
1479 {
1480         struct fsg_dev          *fsg = get_gadget_data(gadget);
1481         int                     rc;
1482         int                     w_length = le16_to_cpu(ctrl->wLength);
1483
1484         ++fsg->ep0_req_tag;             // Record arrival of a new request
1485         fsg->ep0req->context = NULL;
1486         fsg->ep0req->length = 0;
1487         dump_msg(fsg, "ep0-setup", (u8 *) ctrl, sizeof(*ctrl));
1488
1489         if ((ctrl->bRequestType & USB_TYPE_MASK) == USB_TYPE_CLASS)
1490                 rc = class_setup_req(fsg, ctrl);
1491         else
1492                 rc = standard_setup_req(fsg, ctrl);
1493
1494         /* Respond with data/status or defer until later? */
1495         if (rc >= 0 && rc != DELAYED_STATUS) {
1496                 rc = min(rc, w_length);
1497                 fsg->ep0req->length = rc;
1498                 fsg->ep0req->zero = rc < w_length;
1499                 fsg->ep0req_name = (ctrl->bRequestType & USB_DIR_IN ?
1500                                 "ep0-in" : "ep0-out");
1501                 rc = ep0_queue(fsg);
1502         }
1503
1504         /* Device either stalls (rc < 0) or reports success */
1505         return rc;
1506 }
1507
1508
1509 /*-------------------------------------------------------------------------*/
1510
1511 /* All the following routines run in process context */
1512
1513
1514 /* Use this for bulk or interrupt transfers, not ep0 */
1515 static void start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
1516                 struct usb_request *req, int *pbusy,
1517                 enum fsg_buffer_state *state)
1518 {
1519         int     rc;
1520
1521         if (ep == fsg->bulk_in)
1522                 dump_msg(fsg, "bulk-in", req->buf, req->length);
1523         else if (ep == fsg->intr_in)
1524                 dump_msg(fsg, "intr-in", req->buf, req->length);
1525
1526         spin_lock_irq(&fsg->lock);
1527         *pbusy = 1;
1528         *state = BUF_STATE_BUSY;
1529         spin_unlock_irq(&fsg->lock);
1530         rc = usb_ep_queue(ep, req, GFP_KERNEL);
1531         if (rc != 0) {
1532                 *pbusy = 0;
1533                 *state = BUF_STATE_EMPTY;
1534
1535                 /* We can't do much more than wait for a reset */
1536
1537                 /* Note: currently the net2280 driver fails zero-length
1538                  * submissions if DMA is enabled. */
1539                 if (rc != -ESHUTDOWN && !(rc == -EOPNOTSUPP &&
1540                                                 req->length == 0))
1541                         WARNING(fsg, "error in submission: %s --> %d\n",
1542                                         ep->name, rc);
1543         }
1544 }
1545
1546
1547 static int sleep_thread(struct fsg_dev *fsg)
1548 {
1549         int     rc = 0;
1550
1551         /* Wait until a signal arrives or we are woken up */
1552         for (;;) {
1553                 try_to_freeze();
1554                 set_current_state(TASK_INTERRUPTIBLE);
1555                 if (signal_pending(current)) {
1556                         rc = -EINTR;
1557                         break;
1558                 }
1559                 if (fsg->thread_wakeup_needed)
1560                         break;
1561                 schedule();
1562         }
1563         __set_current_state(TASK_RUNNING);
1564         fsg->thread_wakeup_needed = 0;
1565         return rc;
1566 }
1567
1568
1569 /*-------------------------------------------------------------------------*/
1570
1571 static int do_read(struct fsg_dev *fsg)
1572 {
1573         struct lun              *curlun = fsg->curlun;
1574         u32                     lba;
1575         struct fsg_buffhd       *bh;
1576         int                     rc;
1577         u32                     amount_left;
1578         loff_t                  file_offset, file_offset_tmp;
1579         unsigned int            amount;
1580         unsigned int            partial_page;
1581         ssize_t                 nread;
1582
1583         /* Get the starting Logical Block Address and check that it's
1584          * not too big */
1585         if (fsg->cmnd[0] == SC_READ_6)
1586                 lba = (fsg->cmnd[1] << 16) | get_be16(&fsg->cmnd[2]);
1587         else {
1588                 lba = get_be32(&fsg->cmnd[2]);
1589
1590                 /* We allow DPO (Disable Page Out = don't save data in the
1591                  * cache) and FUA (Force Unit Access = don't read from the
1592                  * cache), but we don't implement them. */
1593                 if ((fsg->cmnd[1] & ~0x18) != 0) {
1594                         curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1595                         return -EINVAL;
1596                 }
1597         }
1598         if (lba >= curlun->num_sectors) {
1599                 curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1600                 return -EINVAL;
1601         }
1602         file_offset = ((loff_t) lba) << 9;
1603
1604         /* Carry out the file reads */
1605         amount_left = fsg->data_size_from_cmnd;
1606         if (unlikely(amount_left == 0))
1607                 return -EIO;            // No default reply
1608
1609         for (;;) {
1610
1611                 /* Figure out how much we need to read:
1612                  * Try to read the remaining amount.
1613                  * But don't read more than the buffer size.
1614                  * And don't try to read past the end of the file.
1615                  * Finally, if we're not at a page boundary, don't read past
1616                  *      the next page.
1617                  * If this means reading 0 then we were asked to read past
1618                  *      the end of file. */
1619                 amount = min((unsigned int) amount_left, mod_data.buflen);
1620                 amount = min((loff_t) amount,
1621                                 curlun->file_length - file_offset);
1622                 partial_page = file_offset & (PAGE_CACHE_SIZE - 1);
1623                 if (partial_page > 0)
1624                         amount = min(amount, (unsigned int) PAGE_CACHE_SIZE -
1625                                         partial_page);
1626
1627                 /* Wait for the next buffer to become available */
1628                 bh = fsg->next_buffhd_to_fill;
1629                 while (bh->state != BUF_STATE_EMPTY) {
1630                         rc = sleep_thread(fsg);
1631                         if (rc)
1632                                 return rc;
1633                 }
1634
1635                 /* If we were asked to read past the end of file,
1636                  * end with an empty buffer. */
1637                 if (amount == 0) {
1638                         curlun->sense_data =
1639                                         SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1640                         curlun->sense_data_info = file_offset >> 9;
1641                         curlun->info_valid = 1;
1642                         bh->inreq->length = 0;
1643                         bh->state = BUF_STATE_FULL;
1644                         break;
1645                 }
1646
1647                 /* Perform the read */
1648                 file_offset_tmp = file_offset;
1649                 nread = vfs_read(curlun->filp,
1650                                 (char __user *) bh->buf,
1651                                 amount, &file_offset_tmp);
1652                 VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
1653                                 (unsigned long long) file_offset,
1654                                 (int) nread);
1655                 if (signal_pending(current))
1656                         return -EINTR;
1657
1658                 if (nread < 0) {
1659                         LDBG(curlun, "error in file read: %d\n",
1660                                         (int) nread);
1661                         nread = 0;
1662                 } else if (nread < amount) {
1663                         LDBG(curlun, "partial file read: %d/%u\n",
1664                                         (int) nread, amount);
1665                         nread -= (nread & 511); // Round down to a block
1666                 }
1667                 file_offset  += nread;
1668                 amount_left  -= nread;
1669                 fsg->residue -= nread;
1670                 bh->inreq->length = nread;
1671                 bh->state = BUF_STATE_FULL;
1672
1673                 /* If an error occurred, report it and its position */
1674                 if (nread < amount) {
1675                         curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
1676                         curlun->sense_data_info = file_offset >> 9;
1677                         curlun->info_valid = 1;
1678                         break;
1679                 }
1680
1681                 if (amount_left == 0)
1682                         break;          // No more left to read
1683
1684                 /* Send this buffer and go read some more */
1685                 bh->inreq->zero = 0;
1686                 start_transfer(fsg, fsg->bulk_in, bh->inreq,
1687                                 &bh->inreq_busy, &bh->state);
1688                 fsg->next_buffhd_to_fill = bh->next;
1689         }
1690
1691         return -EIO;            // No default reply
1692 }
1693
1694
1695 /*-------------------------------------------------------------------------*/
1696
1697 static int do_write(struct fsg_dev *fsg)
1698 {
1699         struct lun              *curlun = fsg->curlun;
1700         u32                     lba;
1701         struct fsg_buffhd       *bh;
1702         int                     get_some_more;
1703         u32                     amount_left_to_req, amount_left_to_write;
1704         loff_t                  usb_offset, file_offset, file_offset_tmp;
1705         unsigned int            amount;
1706         unsigned int            partial_page;
1707         ssize_t                 nwritten;
1708         int                     rc;
1709
1710         if (curlun->ro) {
1711                 curlun->sense_data = SS_WRITE_PROTECTED;
1712                 return -EINVAL;
1713         }
1714         spin_lock(&curlun->filp->f_lock);
1715         curlun->filp->f_flags &= ~O_SYNC;       // Default is not to wait
1716         spin_unlock(&curlun->filp->f_lock);
1717
1718         /* Get the starting Logical Block Address and check that it's
1719          * not too big */
1720         if (fsg->cmnd[0] == SC_WRITE_6)
1721                 lba = (fsg->cmnd[1] << 16) | get_be16(&fsg->cmnd[2]);
1722         else {
1723                 lba = get_be32(&fsg->cmnd[2]);
1724
1725                 /* We allow DPO (Disable Page Out = don't save data in the
1726                  * cache) and FUA (Force Unit Access = write directly to the
1727                  * medium).  We don't implement DPO; we implement FUA by
1728                  * performing synchronous output. */
1729                 if ((fsg->cmnd[1] & ~0x18) != 0) {
1730                         curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1731                         return -EINVAL;
1732                 }
1733                 if (fsg->cmnd[1] & 0x08) {      // FUA
1734                         spin_lock(&curlun->filp->f_lock);
1735                         curlun->filp->f_flags |= O_SYNC;
1736                         spin_unlock(&curlun->filp->f_lock);
1737                 }
1738         }
1739         if (lba >= curlun->num_sectors) {
1740                 curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1741                 return -EINVAL;
1742         }
1743
1744         /* Carry out the file writes */
1745         get_some_more = 1;
1746         file_offset = usb_offset = ((loff_t) lba) << 9;
1747         amount_left_to_req = amount_left_to_write = fsg->data_size_from_cmnd;
1748
1749         while (amount_left_to_write > 0) {
1750
1751                 /* Queue a request for more data from the host */
1752                 bh = fsg->next_buffhd_to_fill;
1753                 if (bh->state == BUF_STATE_EMPTY && get_some_more) {
1754
1755                         /* Figure out how much we want to get:
1756                          * Try to get the remaining amount.
1757                          * But don't get more than the buffer size.
1758                          * And don't try to go past the end of the file.
1759                          * If we're not at a page boundary,
1760                          *      don't go past the next page.
1761                          * If this means getting 0, then we were asked
1762                          *      to write past the end of file.
1763                          * Finally, round down to a block boundary. */
1764                         amount = min(amount_left_to_req, mod_data.buflen);
1765                         amount = min((loff_t) amount, curlun->file_length -
1766                                         usb_offset);
1767                         partial_page = usb_offset & (PAGE_CACHE_SIZE - 1);
1768                         if (partial_page > 0)
1769                                 amount = min(amount,
1770         (unsigned int) PAGE_CACHE_SIZE - partial_page);
1771
1772                         if (amount == 0) {
1773                                 get_some_more = 0;
1774                                 curlun->sense_data =
1775                                         SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1776                                 curlun->sense_data_info = usb_offset >> 9;
1777                                 curlun->info_valid = 1;
1778                                 continue;
1779                         }
1780                         amount -= (amount & 511);
1781                         if (amount == 0) {
1782
1783                                 /* Why were we were asked to transfer a
1784                                  * partial block? */
1785                                 get_some_more = 0;
1786                                 continue;
1787                         }
1788
1789                         /* Get the next buffer */
1790                         usb_offset += amount;
1791                         fsg->usb_amount_left -= amount;
1792                         amount_left_to_req -= amount;
1793                         if (amount_left_to_req == 0)
1794                                 get_some_more = 0;
1795
1796                         /* amount is always divisible by 512, hence by
1797                          * the bulk-out maxpacket size */
1798                         bh->outreq->length = bh->bulk_out_intended_length =
1799                                         amount;
1800                         bh->outreq->short_not_ok = 1;
1801                         start_transfer(fsg, fsg->bulk_out, bh->outreq,
1802                                         &bh->outreq_busy, &bh->state);
1803                         fsg->next_buffhd_to_fill = bh->next;
1804                         continue;
1805                 }
1806
1807                 /* Write the received data to the backing file */
1808                 bh = fsg->next_buffhd_to_drain;
1809                 if (bh->state == BUF_STATE_EMPTY && !get_some_more)
1810                         break;                  // We stopped early
1811                 if (bh->state == BUF_STATE_FULL) {
1812                         smp_rmb();
1813                         fsg->next_buffhd_to_drain = bh->next;
1814                         bh->state = BUF_STATE_EMPTY;
1815
1816                         /* Did something go wrong with the transfer? */
1817                         if (bh->outreq->status != 0) {
1818                                 curlun->sense_data = SS_COMMUNICATION_FAILURE;
1819                                 curlun->sense_data_info = file_offset >> 9;
1820                                 curlun->info_valid = 1;
1821                                 break;
1822                         }
1823
1824                         amount = bh->outreq->actual;
1825                         if (curlun->file_length - file_offset < amount) {
1826                                 LERROR(curlun,
1827         "write %u @ %llu beyond end %llu\n",
1828         amount, (unsigned long long) file_offset,
1829         (unsigned long long) curlun->file_length);
1830                                 amount = curlun->file_length - file_offset;
1831                         }
1832
1833                         /* Perform the write */
1834                         file_offset_tmp = file_offset;
1835                         nwritten = vfs_write(curlun->filp,
1836                                         (char __user *) bh->buf,
1837                                         amount, &file_offset_tmp);
1838                         VLDBG(curlun, "file write %u @ %llu -> %d\n", amount,
1839                                         (unsigned long long) file_offset,
1840                                         (int) nwritten);
1841                         if (signal_pending(current))
1842                                 return -EINTR;          // Interrupted!
1843
1844                         if (nwritten < 0) {
1845                                 LDBG(curlun, "error in file write: %d\n",
1846                                                 (int) nwritten);
1847                                 nwritten = 0;
1848                         } else if (nwritten < amount) {
1849                                 LDBG(curlun, "partial file write: %d/%u\n",
1850                                                 (int) nwritten, amount);
1851                                 nwritten -= (nwritten & 511);
1852                                                 // Round down to a block
1853                         }
1854                         file_offset += nwritten;
1855                         amount_left_to_write -= nwritten;
1856                         fsg->residue -= nwritten;
1857
1858                         /* If an error occurred, report it and its position */
1859                         if (nwritten < amount) {
1860                                 curlun->sense_data = SS_WRITE_ERROR;
1861                                 curlun->sense_data_info = file_offset >> 9;
1862                                 curlun->info_valid = 1;
1863                                 break;
1864                         }
1865
1866                         /* Did the host decide to stop early? */
1867                         if (bh->outreq->actual != bh->outreq->length) {
1868                                 fsg->short_packet_received = 1;
1869                                 break;
1870                         }
1871                         continue;
1872                 }
1873
1874                 /* Wait for something to happen */
1875                 rc = sleep_thread(fsg);
1876                 if (rc)
1877                         return rc;
1878         }
1879
1880         return -EIO;            // No default reply
1881 }
1882
1883
1884 /*-------------------------------------------------------------------------*/
1885
1886 /* Sync the file data, don't bother with the metadata.
1887  * This code was copied from fs/buffer.c:sys_fdatasync(). */
1888 static int fsync_sub(struct lun *curlun)
1889 {
1890         struct file     *filp = curlun->filp;
1891
1892         if (curlun->ro || !filp)
1893                 return 0;
1894         return vfs_fsync(filp, filp->f_path.dentry, 1);
1895 }
1896
1897 static void fsync_all(struct fsg_dev *fsg)
1898 {
1899         int     i;
1900
1901         for (i = 0; i < fsg->nluns; ++i)
1902                 fsync_sub(&fsg->luns[i]);
1903 }
1904
1905 static int do_synchronize_cache(struct fsg_dev *fsg)
1906 {
1907         struct lun      *curlun = fsg->curlun;
1908         int             rc;
1909
1910         /* We ignore the requested LBA and write out all file's
1911          * dirty data buffers. */
1912         rc = fsync_sub(curlun);
1913         if (rc)
1914                 curlun->sense_data = SS_WRITE_ERROR;
1915         return 0;
1916 }
1917
1918
1919 /*-------------------------------------------------------------------------*/
1920
1921 static void invalidate_sub(struct lun *curlun)
1922 {
1923         struct file     *filp = curlun->filp;
1924         struct inode    *inode = filp->f_path.dentry->d_inode;
1925         unsigned long   rc;
1926
1927         rc = invalidate_mapping_pages(inode->i_mapping, 0, -1);
1928         VLDBG(curlun, "invalidate_inode_pages -> %ld\n", rc);
1929 }
1930
1931 static int do_verify(struct fsg_dev *fsg)
1932 {
1933         struct lun              *curlun = fsg->curlun;
1934         u32                     lba;
1935         u32                     verification_length;
1936         struct fsg_buffhd       *bh = fsg->next_buffhd_to_fill;
1937         loff_t                  file_offset, file_offset_tmp;
1938         u32                     amount_left;
1939         unsigned int            amount;
1940         ssize_t                 nread;
1941
1942         /* Get the starting Logical Block Address and check that it's
1943          * not too big */
1944         lba = get_be32(&fsg->cmnd[2]);
1945         if (lba >= curlun->num_sectors) {
1946                 curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1947                 return -EINVAL;
1948         }
1949
1950         /* We allow DPO (Disable Page Out = don't save data in the
1951          * cache) but we don't implement it. */
1952         if ((fsg->cmnd[1] & ~0x10) != 0) {
1953                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1954                 return -EINVAL;
1955         }
1956
1957         verification_length = get_be16(&fsg->cmnd[7]);
1958         if (unlikely(verification_length == 0))
1959                 return -EIO;            // No default reply
1960
1961         /* Prepare to carry out the file verify */
1962         amount_left = verification_length << 9;
1963         file_offset = ((loff_t) lba) << 9;
1964
1965         /* Write out all the dirty buffers before invalidating them */
1966         fsync_sub(curlun);
1967         if (signal_pending(current))
1968                 return -EINTR;
1969
1970         invalidate_sub(curlun);
1971         if (signal_pending(current))
1972                 return -EINTR;
1973
1974         /* Just try to read the requested blocks */
1975         while (amount_left > 0) {
1976
1977                 /* Figure out how much we need to read:
1978                  * Try to read the remaining amount, but not more than
1979                  * the buffer size.
1980                  * And don't try to read past the end of the file.
1981                  * If this means reading 0 then we were asked to read
1982                  * past the end of file. */
1983                 amount = min((unsigned int) amount_left, mod_data.buflen);
1984                 amount = min((loff_t) amount,
1985                                 curlun->file_length - file_offset);
1986                 if (amount == 0) {
1987                         curlun->sense_data =
1988                                         SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1989                         curlun->sense_data_info = file_offset >> 9;
1990                         curlun->info_valid = 1;
1991                         break;
1992                 }
1993
1994                 /* Perform the read */
1995                 file_offset_tmp = file_offset;
1996                 nread = vfs_read(curlun->filp,
1997                                 (char __user *) bh->buf,
1998                                 amount, &file_offset_tmp);
1999                 VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
2000                                 (unsigned long long) file_offset,
2001                                 (int) nread);
2002                 if (signal_pending(current))
2003                         return -EINTR;
2004
2005                 if (nread < 0) {
2006                         LDBG(curlun, "error in file verify: %d\n",
2007                                         (int) nread);
2008                         nread = 0;
2009                 } else if (nread < amount) {
2010                         LDBG(curlun, "partial file verify: %d/%u\n",
2011                                         (int) nread, amount);
2012                         nread -= (nread & 511); // Round down to a sector
2013                 }
2014                 if (nread == 0) {
2015                         curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
2016                         curlun->sense_data_info = file_offset >> 9;
2017                         curlun->info_valid = 1;
2018                         break;
2019                 }
2020                 file_offset += nread;
2021                 amount_left -= nread;
2022         }
2023         return 0;
2024 }
2025
2026
2027 /*-------------------------------------------------------------------------*/
2028
2029 static int do_inquiry(struct fsg_dev *fsg, struct fsg_buffhd *bh)
2030 {
2031         u8      *buf = (u8 *) bh->buf;
2032
2033         static char vendor_id[] = "Linux   ";
2034         static char product_disk_id[] = "File-Stor Gadget";
2035         static char product_cdrom_id[] = "File-CD Gadget  ";
2036
2037         if (!fsg->curlun) {             // Unsupported LUNs are okay
2038                 fsg->bad_lun_okay = 1;
2039                 memset(buf, 0, 36);
2040                 buf[0] = 0x7f;          // Unsupported, no device-type
2041                 buf[4] = 31;            // Additional length
2042                 return 36;
2043         }
2044
2045         memset(buf, 0, 8);
2046         buf[0] = (mod_data.cdrom ? TYPE_CDROM : TYPE_DISK);
2047         if (mod_data.removable)
2048                 buf[1] = 0x80;
2049         buf[2] = 2;             // ANSI SCSI level 2
2050         buf[3] = 2;             // SCSI-2 INQUIRY data format
2051         buf[4] = 31;            // Additional length
2052                                 // No special options
2053         sprintf(buf + 8, "%-8s%-16s%04x", vendor_id,
2054                         (mod_data.cdrom ? product_cdrom_id :
2055                                 product_disk_id),
2056                         mod_data.release);
2057         return 36;
2058 }
2059
2060
2061 static int do_request_sense(struct fsg_dev *fsg, struct fsg_buffhd *bh)
2062 {
2063         struct lun      *curlun = fsg->curlun;
2064         u8              *buf = (u8 *) bh->buf;
2065         u32             sd, sdinfo;
2066         int             valid;
2067
2068         /*
2069          * From the SCSI-2 spec., section 7.9 (Unit attention condition):
2070          *
2071          * If a REQUEST SENSE command is received from an initiator
2072          * with a pending unit attention condition (before the target
2073          * generates the contingent allegiance condition), then the
2074          * target shall either:
2075          *   a) report any pending sense data and preserve the unit
2076          *      attention condition on the logical unit, or,
2077          *   b) report the unit attention condition, may discard any
2078          *      pending sense data, and clear the unit attention
2079          *      condition on the logical unit for that initiator.
2080          *
2081          * FSG normally uses option a); enable this code to use option b).
2082          */
2083 #if 0
2084         if (curlun && curlun->unit_attention_data != SS_NO_SENSE) {
2085                 curlun->sense_data = curlun->unit_attention_data;
2086                 curlun->unit_attention_data = SS_NO_SENSE;
2087         }
2088 #endif
2089
2090         if (!curlun) {          // Unsupported LUNs are okay
2091                 fsg->bad_lun_okay = 1;
2092                 sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
2093                 sdinfo = 0;
2094                 valid = 0;
2095         } else {
2096                 sd = curlun->sense_data;
2097                 sdinfo = curlun->sense_data_info;
2098                 valid = curlun->info_valid << 7;
2099                 curlun->sense_data = SS_NO_SENSE;
2100                 curlun->sense_data_info = 0;
2101                 curlun->info_valid = 0;
2102         }
2103
2104         memset(buf, 0, 18);
2105         buf[0] = valid | 0x70;                  // Valid, current error
2106         buf[2] = SK(sd);
2107         put_be32(&buf[3], sdinfo);              // Sense information
2108         buf[7] = 18 - 8;                        // Additional sense length
2109         buf[12] = ASC(sd);
2110         buf[13] = ASCQ(sd);
2111         return 18;
2112 }
2113
2114
2115 static int do_read_capacity(struct fsg_dev *fsg, struct fsg_buffhd *bh)
2116 {
2117         struct lun      *curlun = fsg->curlun;
2118         u32             lba = get_be32(&fsg->cmnd[2]);
2119         int             pmi = fsg->cmnd[8];
2120         u8              *buf = (u8 *) bh->buf;
2121
2122         /* Check the PMI and LBA fields */
2123         if (pmi > 1 || (pmi == 0 && lba != 0)) {
2124                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
2125                 return -EINVAL;
2126         }
2127
2128         put_be32(&buf[0], curlun->num_sectors - 1);     // Max logical block
2129         put_be32(&buf[4], 512);                         // Block length
2130         return 8;
2131 }
2132
2133
2134 static void store_cdrom_address(u8 *dest, int msf, u32 addr)
2135 {
2136         if (msf) {
2137                 /* Convert to Minutes-Seconds-Frames */
2138                 addr >>= 2;             /* Convert to 2048-byte frames */
2139                 addr += 2*75;           /* Lead-in occupies 2 seconds */
2140                 dest[3] = addr % 75;    /* Frames */
2141                 addr /= 75;
2142                 dest[2] = addr % 60;    /* Seconds */
2143                 addr /= 60;
2144                 dest[1] = addr;         /* Minutes */
2145                 dest[0] = 0;            /* Reserved */
2146         } else {
2147                 /* Absolute sector */
2148                 put_be32(dest, addr);
2149         }
2150 }
2151
2152 static int do_read_header(struct fsg_dev *fsg, struct fsg_buffhd *bh)
2153 {
2154         struct lun      *curlun = fsg->curlun;
2155         int             msf = fsg->cmnd[1] & 0x02;
2156         u32             lba = get_be32(&fsg->cmnd[2]);
2157         u8              *buf = (u8 *) bh->buf;
2158
2159         if ((fsg->cmnd[1] & ~0x02) != 0) {              /* Mask away MSF */
2160                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
2161                 return -EINVAL;
2162         }
2163         if (lba >= curlun->num_sectors) {
2164                 curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
2165                 return -EINVAL;
2166         }
2167
2168         memset(buf, 0, 8);
2169         buf[0] = 0x01;          /* 2048 bytes of user data, rest is EC */
2170         store_cdrom_address(&buf[4], msf, lba);
2171         return 8;
2172 }
2173
2174
2175 static int do_read_toc(struct fsg_dev *fsg, struct fsg_buffhd *bh)
2176 {
2177         struct lun      *curlun = fsg->curlun;
2178         int             msf = fsg->cmnd[1] & 0x02;
2179         int             start_track = fsg->cmnd[6];
2180         u8              *buf = (u8 *) bh->buf;
2181
2182         if ((fsg->cmnd[1] & ~0x02) != 0 ||              /* Mask away MSF */
2183                         start_track > 1) {
2184                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
2185                 return -EINVAL;
2186         }
2187
2188         memset(buf, 0, 20);
2189         buf[1] = (20-2);                /* TOC data length */
2190         buf[2] = 1;                     /* First track number */
2191         buf[3] = 1;                     /* Last track number */
2192         buf[5] = 0x16;                  /* Data track, copying allowed */
2193         buf[6] = 0x01;                  /* Only track is number 1 */
2194         store_cdrom_address(&buf[8], msf, 0);
2195
2196         buf[13] = 0x16;                 /* Lead-out track is data */
2197         buf[14] = 0xAA;                 /* Lead-out track number */
2198         store_cdrom_address(&buf[16], msf, curlun->num_sectors);
2199         return 20;
2200 }
2201
2202
2203 static int do_mode_sense(struct fsg_dev *fsg, struct fsg_buffhd *bh)
2204 {
2205         struct lun      *curlun = fsg->curlun;
2206         int             mscmnd = fsg->cmnd[0];
2207         u8              *buf = (u8 *) bh->buf;
2208         u8              *buf0 = buf;
2209         int             pc, page_code;
2210         int             changeable_values, all_pages;
2211         int             valid_page = 0;
2212         int             len, limit;
2213
2214         if ((fsg->cmnd[1] & ~0x08) != 0) {              // Mask away DBD
2215                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
2216                 return -EINVAL;
2217         }
2218         pc = fsg->cmnd[2] >> 6;
2219         page_code = fsg->cmnd[2] & 0x3f;
2220         if (pc == 3) {
2221                 curlun->sense_data = SS_SAVING_PARAMETERS_NOT_SUPPORTED;
2222                 return -EINVAL;
2223         }
2224         changeable_values = (pc == 1);
2225         all_pages = (page_code == 0x3f);
2226
2227         /* Write the mode parameter header.  Fixed values are: default
2228          * medium type, no cache control (DPOFUA), and no block descriptors.
2229          * The only variable value is the WriteProtect bit.  We will fill in
2230          * the mode data length later. */
2231         memset(buf, 0, 8);
2232         if (mscmnd == SC_MODE_SENSE_6) {
2233                 buf[2] = (curlun->ro ? 0x80 : 0x00);            // WP, DPOFUA
2234                 buf += 4;
2235                 limit = 255;
2236         } else {                        // SC_MODE_SENSE_10
2237                 buf[3] = (curlun->ro ? 0x80 : 0x00);            // WP, DPOFUA
2238                 buf += 8;
2239                 limit = 65535;          // Should really be mod_data.buflen
2240         }
2241
2242         /* No block descriptors */
2243
2244         /* The mode pages, in numerical order.  The only page we support
2245          * is the Caching page. */
2246         if (page_code == 0x08 || all_pages) {
2247                 valid_page = 1;
2248                 buf[0] = 0x08;          // Page code
2249                 buf[1] = 10;            // Page length
2250                 memset(buf+2, 0, 10);   // None of the fields are changeable
2251
2252                 if (!changeable_values) {
2253                         buf[2] = 0x04;  // Write cache enable,
2254                                         // Read cache not disabled
2255                                         // No cache retention priorities
2256                         put_be16(&buf[4], 0xffff);  // Don't disable prefetch
2257                                         // Minimum prefetch = 0
2258                         put_be16(&buf[8], 0xffff);  // Maximum prefetch
2259                         put_be16(&buf[10], 0xffff); // Maximum prefetch ceiling
2260                 }
2261                 buf += 12;
2262         }
2263
2264         /* Check that a valid page was requested and the mode data length
2265          * isn't too long. */
2266         len = buf - buf0;
2267         if (!valid_page || len > limit) {
2268                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
2269                 return -EINVAL;
2270         }
2271
2272         /*  Store the mode data length */
2273         if (mscmnd == SC_MODE_SENSE_6)
2274                 buf0[0] = len - 1;
2275         else
2276                 put_be16(buf0, len - 2);
2277         return len;
2278 }
2279
2280
2281 static int do_start_stop(struct fsg_dev *fsg)
2282 {
2283         struct lun      *curlun = fsg->curlun;
2284         int             loej, start;
2285
2286         if (!mod_data.removable) {
2287                 curlun->sense_data = SS_INVALID_COMMAND;
2288                 return -EINVAL;
2289         }
2290
2291         // int immed = fsg->cmnd[1] & 0x01;
2292         loej = fsg->cmnd[4] & 0x02;
2293         start = fsg->cmnd[4] & 0x01;
2294
2295 #ifdef CONFIG_USB_FILE_STORAGE_TEST
2296         if ((fsg->cmnd[1] & ~0x01) != 0 ||              // Mask away Immed
2297                         (fsg->cmnd[4] & ~0x03) != 0) {  // Mask LoEj, Start
2298                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
2299                 return -EINVAL;
2300         }
2301
2302         if (!start) {
2303
2304                 /* Are we allowed to unload the media? */
2305                 if (curlun->prevent_medium_removal) {
2306                         LDBG(curlun, "unload attempt prevented\n");
2307                         curlun->sense_data = SS_MEDIUM_REMOVAL_PREVENTED;
2308                         return -EINVAL;
2309                 }
2310                 if (loej) {             // Simulate an unload/eject
2311                         up_read(&fsg->filesem);
2312                         down_write(&fsg->filesem);
2313                         close_backing_file(curlun);
2314                         up_write(&fsg->filesem);
2315                         down_read(&fsg->filesem);
2316                 }
2317         } else {
2318
2319                 /* Our emulation doesn't support mounting; the medium is
2320                  * available for use as soon as it is loaded. */
2321                 if (!backing_file_is_open(curlun)) {
2322                         curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
2323                         return -EINVAL;
2324                 }
2325         }
2326 #endif
2327         return 0;
2328 }
2329
2330
2331 static int do_prevent_allow(struct fsg_dev *fsg)
2332 {
2333         struct lun      *curlun = fsg->curlun;
2334         int             prevent;
2335
2336         if (!mod_data.removable) {
2337                 curlun->sense_data = SS_INVALID_COMMAND;
2338                 return -EINVAL;
2339         }
2340
2341         prevent = fsg->cmnd[4] & 0x01;
2342         if ((fsg->cmnd[4] & ~0x01) != 0) {              // Mask away Prevent
2343                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
2344                 return -EINVAL;
2345         }
2346
2347         if (curlun->prevent_medium_removal && !prevent)
2348                 fsync_sub(curlun);
2349         curlun->prevent_medium_removal = prevent;
2350         return 0;
2351 }
2352
2353
2354 static int do_read_format_capacities(struct fsg_dev *fsg,
2355                         struct fsg_buffhd *bh)
2356 {
2357         struct lun      *curlun = fsg->curlun;
2358         u8              *buf = (u8 *) bh->buf;
2359
2360         buf[0] = buf[1] = buf[2] = 0;
2361         buf[3] = 8;             // Only the Current/Maximum Capacity Descriptor
2362         buf += 4;
2363
2364         put_be32(&buf[0], curlun->num_sectors);         // Number of blocks
2365         put_be32(&buf[4], 512);                         // Block length
2366         buf[4] = 0x02;                                  // Current capacity
2367         return 12;
2368 }
2369
2370
2371 static int do_mode_select(struct fsg_dev *fsg, struct fsg_buffhd *bh)
2372 {
2373         struct lun      *curlun = fsg->curlun;
2374
2375         /* We don't support MODE SELECT */
2376         curlun->sense_data = SS_INVALID_COMMAND;
2377         return -EINVAL;
2378 }
2379
2380
2381 /*-------------------------------------------------------------------------*/
2382
2383 static int halt_bulk_in_endpoint(struct fsg_dev *fsg)
2384 {
2385         int     rc;
2386
2387         rc = fsg_set_halt(fsg, fsg->bulk_in);
2388         if (rc == -EAGAIN)
2389                 VDBG(fsg, "delayed bulk-in endpoint halt\n");
2390         while (rc != 0) {
2391                 if (rc != -EAGAIN) {
2392                         WARNING(fsg, "usb_ep_set_halt -> %d\n", rc);
2393                         rc = 0;
2394                         break;
2395                 }
2396
2397                 /* Wait for a short time and then try again */
2398                 if (msleep_interruptible(100) != 0)
2399                         return -EINTR;
2400                 rc = usb_ep_set_halt(fsg->bulk_in);
2401         }
2402         return rc;
2403 }
2404
2405 static int wedge_bulk_in_endpoint(struct fsg_dev *fsg)
2406 {
2407         int     rc;
2408
2409         DBG(fsg, "bulk-in set wedge\n");
2410         rc = usb_ep_set_wedge(fsg->bulk_in);
2411         if (rc == -EAGAIN)
2412                 VDBG(fsg, "delayed bulk-in endpoint wedge\n");
2413         while (rc != 0) {
2414                 if (rc != -EAGAIN) {
2415                         WARNING(fsg, "usb_ep_set_wedge -> %d\n", rc);
2416                         rc = 0;
2417                         break;
2418                 }
2419
2420                 /* Wait for a short time and then try again */
2421                 if (msleep_interruptible(100) != 0)
2422                         return -EINTR;
2423                 rc = usb_ep_set_wedge(fsg->bulk_in);
2424         }
2425         return rc;
2426 }
2427
2428 static int pad_with_zeros(struct fsg_dev *fsg)
2429 {
2430         struct fsg_buffhd       *bh = fsg->next_buffhd_to_fill;
2431         u32                     nkeep = bh->inreq->length;
2432         u32                     nsend;
2433         int                     rc;
2434
2435         bh->state = BUF_STATE_EMPTY;            // For the first iteration
2436         fsg->usb_amount_left = nkeep + fsg->residue;
2437         while (fsg->usb_amount_left > 0) {
2438
2439                 /* Wait for the next buffer to be free */
2440                 while (bh->state != BUF_STATE_EMPTY) {
2441                         rc = sleep_thread(fsg);
2442                         if (rc)
2443                                 return rc;
2444                 }
2445
2446                 nsend = min(fsg->usb_amount_left, (u32) mod_data.buflen);
2447                 memset(bh->buf + nkeep, 0, nsend - nkeep);
2448                 bh->inreq->length = nsend;
2449                 bh->inreq->zero = 0;
2450                 start_transfer(fsg, fsg->bulk_in, bh->inreq,
2451                                 &bh->inreq_busy, &bh->state);
2452                 bh = fsg->next_buffhd_to_fill = bh->next;
2453                 fsg->usb_amount_left -= nsend;
2454                 nkeep = 0;
2455         }
2456         return 0;
2457 }
2458
2459 static int throw_away_data(struct fsg_dev *fsg)
2460 {
2461         struct fsg_buffhd       *bh;
2462         u32                     amount;
2463         int                     rc;
2464
2465         while ((bh = fsg->next_buffhd_to_drain)->state != BUF_STATE_EMPTY ||
2466                         fsg->usb_amount_left > 0) {
2467
2468                 /* Throw away the data in a filled buffer */
2469                 if (bh->state == BUF_STATE_FULL) {
2470                         smp_rmb();
2471                         bh->state = BUF_STATE_EMPTY;
2472                         fsg->next_buffhd_to_drain = bh->next;
2473
2474                         /* A short packet or an error ends everything */
2475                         if (bh->outreq->actual != bh->outreq->length ||
2476                                         bh->outreq->status != 0) {
2477                                 raise_exception(fsg, FSG_STATE_ABORT_BULK_OUT);
2478                                 return -EINTR;
2479                         }
2480                         continue;
2481                 }
2482
2483                 /* Try to submit another request if we need one */
2484                 bh = fsg->next_buffhd_to_fill;
2485                 if (bh->state == BUF_STATE_EMPTY && fsg->usb_amount_left > 0) {
2486                         amount = min(fsg->usb_amount_left,
2487                                         (u32) mod_data.buflen);
2488
2489                         /* amount is always divisible by 512, hence by
2490                          * the bulk-out maxpacket size */
2491                         bh->outreq->length = bh->bulk_out_intended_length =
2492                                         amount;
2493                         bh->outreq->short_not_ok = 1;
2494                         start_transfer(fsg, fsg->bulk_out, bh->outreq,
2495                                         &bh->outreq_busy, &bh->state);
2496                         fsg->next_buffhd_to_fill = bh->next;
2497                         fsg->usb_amount_left -= amount;
2498                         continue;
2499                 }
2500
2501                 /* Otherwise wait for something to happen */
2502                 rc = sleep_thread(fsg);
2503                 if (rc)
2504                         return rc;
2505         }
2506         return 0;
2507 }
2508
2509
2510 static int finish_reply(struct fsg_dev *fsg)
2511 {
2512         struct fsg_buffhd       *bh = fsg->next_buffhd_to_fill;
2513         int                     rc = 0;
2514
2515         switch (fsg->data_dir) {
2516         case DATA_DIR_NONE:
2517                 break;                  // Nothing to send
2518
2519         /* If we don't know whether the host wants to read or write,
2520          * this must be CB or CBI with an unknown command.  We mustn't
2521          * try to send or receive any data.  So stall both bulk pipes
2522          * if we can and wait for a reset. */
2523         case DATA_DIR_UNKNOWN:
2524                 if (mod_data.can_stall) {
2525                         fsg_set_halt(fsg, fsg->bulk_out);
2526                         rc = halt_bulk_in_endpoint(fsg);
2527                 }
2528                 break;
2529
2530         /* All but the last buffer of data must have already been sent */
2531         case DATA_DIR_TO_HOST:
2532                 if (fsg->data_size == 0)
2533                         ;               // Nothing to send
2534
2535                 /* If there's no residue, simply send the last buffer */
2536                 else if (fsg->residue == 0) {
2537                         bh->inreq->zero = 0;
2538                         start_transfer(fsg, fsg->bulk_in, bh->inreq,
2539                                         &bh->inreq_busy, &bh->state);
2540                         fsg->next_buffhd_to_fill = bh->next;
2541                 }
2542
2543                 /* There is a residue.  For CB and CBI, simply mark the end
2544                  * of the data with a short packet.  However, if we are
2545                  * allowed to stall, there was no data at all (residue ==
2546                  * data_size), and the command failed (invalid LUN or
2547                  * sense data is set), then halt the bulk-in endpoint
2548                  * instead. */
2549                 else if (!transport_is_bbb()) {
2550                         if (mod_data.can_stall &&
2551                                         fsg->residue == fsg->data_size &&
2552         (!fsg->curlun || fsg->curlun->sense_data != SS_NO_SENSE)) {
2553                                 bh->state = BUF_STATE_EMPTY;
2554                                 rc = halt_bulk_in_endpoint(fsg);
2555                         } else {
2556                                 bh->inreq->zero = 1;
2557                                 start_transfer(fsg, fsg->bulk_in, bh->inreq,
2558                                                 &bh->inreq_busy, &bh->state);
2559                                 fsg->next_buffhd_to_fill = bh->next;
2560                         }
2561                 }
2562
2563                 /* For Bulk-only, if we're allowed to stall then send the
2564                  * short packet and halt the bulk-in endpoint.  If we can't
2565                  * stall, pad out the remaining data with 0's. */
2566                 else {
2567                         if (mod_data.can_stall) {
2568                                 bh->inreq->zero = 1;
2569                                 start_transfer(fsg, fsg->bulk_in, bh->inreq,
2570                                                 &bh->inreq_busy, &bh->state);
2571                                 fsg->next_buffhd_to_fill = bh->next;
2572                                 rc = halt_bulk_in_endpoint(fsg);
2573                         } else
2574                                 rc = pad_with_zeros(fsg);
2575                 }
2576                 break;
2577
2578         /* We have processed all we want from the data the host has sent.
2579          * There may still be outstanding bulk-out requests. */
2580         case DATA_DIR_FROM_HOST:
2581                 if (fsg->residue == 0)
2582                         ;               // Nothing to receive
2583
2584                 /* Did the host stop sending unexpectedly early? */
2585                 else if (fsg->short_packet_received) {
2586                         raise_exception(fsg, FSG_STATE_ABORT_BULK_OUT);
2587                         rc = -EINTR;
2588                 }
2589
2590                 /* We haven't processed all the incoming data.  Even though
2591                  * we may be allowed to stall, doing so would cause a race.
2592                  * The controller may already have ACK'ed all the remaining
2593                  * bulk-out packets, in which case the host wouldn't see a
2594                  * STALL.  Not realizing the endpoint was halted, it wouldn't
2595                  * clear the halt -- leading to problems later on. */
2596 #if 0
2597                 else if (mod_data.can_stall) {
2598                         fsg_set_halt(fsg, fsg->bulk_out);
2599                         raise_exception(fsg, FSG_STATE_ABORT_BULK_OUT);
2600                         rc = -EINTR;
2601                 }
2602 #endif
2603
2604                 /* We can't stall.  Read in the excess data and throw it
2605                  * all away. */
2606                 else
2607                         rc = throw_away_data(fsg);
2608                 break;
2609         }
2610         return rc;
2611 }
2612
2613
2614 static int send_status(struct fsg_dev *fsg)
2615 {
2616         struct lun              *curlun = fsg->curlun;
2617         struct fsg_buffhd       *bh;
2618         int                     rc;
2619         u8                      status = USB_STATUS_PASS;
2620         u32                     sd, sdinfo = 0;
2621
2622         /* Wait for the next buffer to become available */
2623         bh = fsg->next_buffhd_to_fill;
2624         while (bh->state != BUF_STATE_EMPTY) {
2625                 rc = sleep_thread(fsg);
2626                 if (rc)
2627                         return rc;
2628         }
2629
2630         if (curlun) {
2631                 sd = curlun->sense_data;
2632                 sdinfo = curlun->sense_data_info;
2633         } else if (fsg->bad_lun_okay)
2634                 sd = SS_NO_SENSE;
2635         else
2636                 sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
2637
2638         if (fsg->phase_error) {
2639                 DBG(fsg, "sending phase-error status\n");
2640                 status = USB_STATUS_PHASE_ERROR;
2641                 sd = SS_INVALID_COMMAND;
2642         } else if (sd != SS_NO_SENSE) {
2643                 DBG(fsg, "sending command-failure status\n");
2644                 status = USB_STATUS_FAIL;
2645                 VDBG(fsg, "  sense data: SK x%02x, ASC x%02x, ASCQ x%02x;"
2646                                 "  info x%x\n",
2647                                 SK(sd), ASC(sd), ASCQ(sd), sdinfo);
2648         }
2649
2650         if (transport_is_bbb()) {
2651                 struct bulk_cs_wrap     *csw = bh->buf;
2652
2653                 /* Store and send the Bulk-only CSW */
2654                 csw->Signature = cpu_to_le32(USB_BULK_CS_SIG);
2655                 csw->Tag = fsg->tag;
2656                 csw->Residue = cpu_to_le32(fsg->residue);
2657                 csw->Status = status;
2658
2659                 bh->inreq->length = USB_BULK_CS_WRAP_LEN;
2660                 bh->inreq->zero = 0;
2661                 start_transfer(fsg, fsg->bulk_in, bh->inreq,
2662                                 &bh->inreq_busy, &bh->state);
2663
2664         } else if (mod_data.transport_type == USB_PR_CB) {
2665
2666                 /* Control-Bulk transport has no status phase! */
2667                 return 0;
2668
2669         } else {                        // USB_PR_CBI
2670                 struct interrupt_data   *buf = bh->buf;
2671
2672                 /* Store and send the Interrupt data.  UFI sends the ASC
2673                  * and ASCQ bytes.  Everything else sends a Type (which
2674                  * is always 0) and the status Value. */
2675                 if (mod_data.protocol_type == USB_SC_UFI) {
2676                         buf->bType = ASC(sd);
2677                         buf->bValue = ASCQ(sd);
2678                 } else {
2679                         buf->bType = 0;
2680                         buf->bValue = status;
2681                 }
2682                 fsg->intreq->length = CBI_INTERRUPT_DATA_LEN;
2683
2684                 fsg->intr_buffhd = bh;          // Point to the right buffhd
2685                 fsg->intreq->buf = bh->inreq->buf;
2686                 fsg->intreq->context = bh;
2687                 start_transfer(fsg, fsg->intr_in, fsg->intreq,
2688                                 &fsg->intreq_busy, &bh->state);
2689         }
2690
2691         fsg->next_buffhd_to_fill = bh->next;
2692         return 0;
2693 }
2694
2695
2696 /*-------------------------------------------------------------------------*/
2697
2698 /* Check whether the command is properly formed and whether its data size
2699  * and direction agree with the values we already have. */
2700 static int check_command(struct fsg_dev *fsg, int cmnd_size,
2701                 enum data_direction data_dir, unsigned int mask,
2702                 int needs_medium, const char *name)
2703 {
2704         int                     i;
2705         int                     lun = fsg->cmnd[1] >> 5;
2706         static const char       dirletter[4] = {'u', 'o', 'i', 'n'};
2707         char                    hdlen[20];
2708         struct lun              *curlun;
2709
2710         /* Adjust the expected cmnd_size for protocol encapsulation padding.
2711          * Transparent SCSI doesn't pad. */
2712         if (protocol_is_scsi())
2713                 ;
2714
2715         /* There's some disagreement as to whether RBC pads commands or not.
2716          * We'll play it safe and accept either form. */
2717         else if (mod_data.protocol_type == USB_SC_RBC) {
2718                 if (fsg->cmnd_size == 12)
2719                         cmnd_size = 12;
2720
2721         /* All the other protocols pad to 12 bytes */
2722         } else
2723                 cmnd_size = 12;
2724
2725         hdlen[0] = 0;
2726         if (fsg->data_dir != DATA_DIR_UNKNOWN)
2727                 sprintf(hdlen, ", H%c=%u", dirletter[(int) fsg->data_dir],
2728                                 fsg->data_size);
2729         VDBG(fsg, "SCSI command: %s;  Dc=%d, D%c=%u;  Hc=%d%s\n",
2730                         name, cmnd_size, dirletter[(int) data_dir],
2731                         fsg->data_size_from_cmnd, fsg->cmnd_size, hdlen);
2732
2733         /* We can't reply at all until we know the correct data direction
2734          * and size. */
2735         if (fsg->data_size_from_cmnd == 0)
2736                 data_dir = DATA_DIR_NONE;
2737         if (fsg->data_dir == DATA_DIR_UNKNOWN) {        // CB or CBI
2738                 fsg->data_dir = data_dir;
2739                 fsg->data_size = fsg->data_size_from_cmnd;
2740
2741         } else {                                        // Bulk-only
2742                 if (fsg->data_size < fsg->data_size_from_cmnd) {
2743
2744                         /* Host data size < Device data size is a phase error.
2745                          * Carry out the command, but only transfer as much
2746                          * as we are allowed. */
2747                         fsg->data_size_from_cmnd = fsg->data_size;
2748                         fsg->phase_error = 1;
2749                 }
2750         }
2751         fsg->residue = fsg->usb_amount_left = fsg->data_size;
2752
2753         /* Conflicting data directions is a phase error */
2754         if (fsg->data_dir != data_dir && fsg->data_size_from_cmnd > 0) {
2755                 fsg->phase_error = 1;
2756                 return -EINVAL;
2757         }
2758
2759         /* Verify the length of the command itself */
2760         if (cmnd_size != fsg->cmnd_size) {
2761
2762                 /* Special case workaround: There are plenty of buggy SCSI
2763                  * implementations. Many have issues with cbw->Length
2764                  * field passing a wrong command size. For those cases we
2765                  * always try to work around the problem by using the length
2766                  * sent by the host side provided it is at least as large
2767                  * as the correct command length.
2768                  * Examples of such cases would be MS-Windows, which issues
2769                  * REQUEST SENSE with cbw->Length == 12 where it should
2770                  * be 6, and xbox360 issuing INQUIRY, TEST UNIT READY and
2771                  * REQUEST SENSE with cbw->Length == 10 where it should
2772                  * be 6 as well.
2773                  */
2774                 if (cmnd_size <= fsg->cmnd_size) {
2775                         DBG(fsg, "%s is buggy! Expected length %d "
2776                                         "but we got %d\n", name,
2777                                         cmnd_size, fsg->cmnd_size);
2778                         cmnd_size = fsg->cmnd_size;
2779                 } else {
2780                         fsg->phase_error = 1;
2781                         return -EINVAL;
2782                 }
2783         }
2784
2785         /* Check that the LUN values are consistent */
2786         if (transport_is_bbb()) {
2787                 if (fsg->lun != lun)
2788                         DBG(fsg, "using LUN %d from CBW, "
2789                                         "not LUN %d from CDB\n",
2790                                         fsg->lun, lun);
2791         } else
2792                 fsg->lun = lun;         // Use LUN from the command
2793
2794         /* Check the LUN */
2795         if (fsg->lun >= 0 && fsg->lun < fsg->nluns) {
2796                 fsg->curlun = curlun = &fsg->luns[fsg->lun];
2797                 if (fsg->cmnd[0] != SC_REQUEST_SENSE) {
2798                         curlun->sense_data = SS_NO_SENSE;
2799                         curlun->sense_data_info = 0;
2800                         curlun->info_valid = 0;
2801                 }
2802         } else {
2803                 fsg->curlun = curlun = NULL;
2804                 fsg->bad_lun_okay = 0;
2805
2806                 /* INQUIRY and REQUEST SENSE commands are explicitly allowed
2807                  * to use unsupported LUNs; all others may not. */
2808                 if (fsg->cmnd[0] != SC_INQUIRY &&
2809                                 fsg->cmnd[0] != SC_REQUEST_SENSE) {
2810                         DBG(fsg, "unsupported LUN %d\n", fsg->lun);
2811                         return -EINVAL;
2812                 }
2813         }
2814
2815         /* If a unit attention condition exists, only INQUIRY and
2816          * REQUEST SENSE commands are allowed; anything else must fail. */
2817         if (curlun && curlun->unit_attention_data != SS_NO_SENSE &&
2818                         fsg->cmnd[0] != SC_INQUIRY &&
2819                         fsg->cmnd[0] != SC_REQUEST_SENSE) {
2820                 curlun->sense_data = curlun->unit_attention_data;
2821                 curlun->unit_attention_data = SS_NO_SENSE;
2822                 return -EINVAL;
2823         }
2824
2825         /* Check that only command bytes listed in the mask are non-zero */
2826         fsg->cmnd[1] &= 0x1f;                   // Mask away the LUN
2827         for (i = 1; i < cmnd_size; ++i) {
2828                 if (fsg->cmnd[i] && !(mask & (1 << i))) {
2829                         if (curlun)
2830                                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
2831                         return -EINVAL;
2832                 }
2833         }
2834
2835         /* If the medium isn't mounted and the command needs to access
2836          * it, return an error. */
2837         if (curlun && !backing_file_is_open(curlun) && needs_medium) {
2838                 curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
2839                 return -EINVAL;
2840         }
2841
2842         return 0;
2843 }
2844
2845
2846 static int do_scsi_command(struct fsg_dev *fsg)
2847 {
2848         struct fsg_buffhd       *bh;
2849         int                     rc;
2850         int                     reply = -EINVAL;
2851         int                     i;
2852         static char             unknown[16];
2853
2854         dump_cdb(fsg);
2855
2856         /* Wait for the next buffer to become available for data or status */
2857         bh = fsg->next_buffhd_to_drain = fsg->next_buffhd_to_fill;
2858         while (bh->state != BUF_STATE_EMPTY) {
2859                 rc = sleep_thread(fsg);
2860                 if (rc)
2861                         return rc;
2862         }
2863         fsg->phase_error = 0;
2864         fsg->short_packet_received = 0;
2865
2866         down_read(&fsg->filesem);       // We're using the backing file
2867         switch (fsg->cmnd[0]) {
2868
2869         case SC_INQUIRY:
2870                 fsg->data_size_from_cmnd = fsg->cmnd[4];
2871                 if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
2872                                 (1<<4), 0,
2873                                 "INQUIRY")) == 0)
2874                         reply = do_inquiry(fsg, bh);
2875                 break;
2876
2877         case SC_MODE_SELECT_6:
2878                 fsg->data_size_from_cmnd = fsg->cmnd[4];
2879                 if ((reply = check_command(fsg, 6, DATA_DIR_FROM_HOST,
2880                                 (1<<1) | (1<<4), 0,
2881                                 "MODE SELECT(6)")) == 0)
2882                         reply = do_mode_select(fsg, bh);
2883                 break;
2884
2885         case SC_MODE_SELECT_10:
2886                 fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
2887                 if ((reply = check_command(fsg, 10, DATA_DIR_FROM_HOST,
2888                                 (1<<1) | (3<<7), 0,
2889                                 "MODE SELECT(10)")) == 0)
2890                         reply = do_mode_select(fsg, bh);
2891                 break;
2892
2893         case SC_MODE_SENSE_6:
2894                 fsg->data_size_from_cmnd = fsg->cmnd[4];
2895                 if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
2896                                 (1<<1) | (1<<2) | (1<<4), 0,
2897                                 "MODE SENSE(6)")) == 0)
2898                         reply = do_mode_sense(fsg, bh);
2899                 break;
2900
2901         case SC_MODE_SENSE_10:
2902                 fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
2903                 if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
2904                                 (1<<1) | (1<<2) | (3<<7), 0,
2905                                 "MODE SENSE(10)")) == 0)
2906                         reply = do_mode_sense(fsg, bh);
2907                 break;
2908
2909         case SC_PREVENT_ALLOW_MEDIUM_REMOVAL:
2910                 fsg->data_size_from_cmnd = 0;
2911                 if ((reply = check_command(fsg, 6, DATA_DIR_NONE,
2912                                 (1<<4), 0,
2913                                 "PREVENT-ALLOW MEDIUM REMOVAL")) == 0)
2914                         reply = do_prevent_allow(fsg);
2915                 break;
2916
2917         case SC_READ_6:
2918                 i = fsg->cmnd[4];
2919                 fsg->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
2920                 if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
2921                                 (7<<1) | (1<<4), 1,
2922                                 "READ(6)")) == 0)
2923                         reply = do_read(fsg);
2924                 break;
2925
2926         case SC_READ_10:
2927                 fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]) << 9;
2928                 if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
2929                                 (1<<1) | (0xf<<2) | (3<<7), 1,
2930                                 "READ(10)")) == 0)
2931                         reply = do_read(fsg);
2932                 break;
2933
2934         case SC_READ_12:
2935                 fsg->data_size_from_cmnd = get_be32(&fsg->cmnd[6]) << 9;
2936                 if ((reply = check_command(fsg, 12, DATA_DIR_TO_HOST,
2937                                 (1<<1) | (0xf<<2) | (0xf<<6), 1,
2938                                 "READ(12)")) == 0)
2939                         reply = do_read(fsg);
2940                 break;
2941
2942         case SC_READ_CAPACITY:
2943                 fsg->data_size_from_cmnd = 8;
2944                 if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
2945                                 (0xf<<2) | (1<<8), 1,
2946                                 "READ CAPACITY")) == 0)
2947                         reply = do_read_capacity(fsg, bh);
2948                 break;
2949
2950         case SC_READ_HEADER:
2951                 if (!mod_data.cdrom)
2952                         goto unknown_cmnd;
2953                 fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
2954                 if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
2955                                 (3<<7) | (0x1f<<1), 1,
2956                                 "READ HEADER")) == 0)
2957                         reply = do_read_header(fsg, bh);
2958                 break;
2959
2960         case SC_READ_TOC:
2961                 if (!mod_data.cdrom)
2962                         goto unknown_cmnd;
2963                 fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
2964                 if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
2965                                 (7<<6) | (1<<1), 1,
2966                                 "READ TOC")) == 0)
2967                         reply = do_read_toc(fsg, bh);
2968                 break;
2969
2970         case SC_READ_FORMAT_CAPACITIES:
2971                 fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
2972                 if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
2973                                 (3<<7), 1,
2974                                 "READ FORMAT CAPACITIES")) == 0)
2975                         reply = do_read_format_capacities(fsg, bh);
2976                 break;
2977
2978         case SC_REQUEST_SENSE:
2979                 fsg->data_size_from_cmnd = fsg->cmnd[4];
2980                 if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
2981                                 (1<<4), 0,
2982                                 "REQUEST SENSE")) == 0)
2983                         reply = do_request_sense(fsg, bh);
2984                 break;
2985
2986         case SC_START_STOP_UNIT:
2987                 fsg->data_size_from_cmnd = 0;
2988                 if ((reply = check_command(fsg, 6, DATA_DIR_NONE,
2989                                 (1<<1) | (1<<4), 0,
2990                                 "START-STOP UNIT")) == 0)
2991                         reply = do_start_stop(fsg);
2992                 break;
2993
2994         case SC_SYNCHRONIZE_CACHE:
2995                 fsg->data_size_from_cmnd = 0;
2996                 if ((reply = check_command(fsg, 10, DATA_DIR_NONE,
2997                                 (0xf<<2) | (3<<7), 1,
2998                                 "SYNCHRONIZE CACHE")) == 0)
2999                         reply = do_synchronize_cache(fsg);
3000                 break;
3001
3002         case SC_TEST_UNIT_READY:
3003                 fsg->data_size_from_cmnd = 0;
3004                 reply = check_command(fsg, 6, DATA_DIR_NONE,
3005                                 0, 1,
3006                                 "TEST UNIT READY");
3007                 break;
3008
3009         /* Although optional, this command is used by MS-Windows.  We
3010          * support a minimal version: BytChk must be 0. */
3011         case SC_VERIFY:
3012                 fsg->data_size_from_cmnd = 0;
3013                 if ((reply = check_command(fsg, 10, DATA_DIR_NONE,
3014                                 (1<<1) | (0xf<<2) | (3<<7), 1,
3015                                 "VERIFY")) == 0)
3016                         reply = do_verify(fsg);
3017                 break;
3018
3019         case SC_WRITE_6:
3020                 i = fsg->cmnd[4];
3021                 fsg->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
3022                 if ((reply = check_command(fsg, 6, DATA_DIR_FROM_HOST,
3023                                 (7<<1) | (1<<4), 1,
3024                                 "WRITE(6)")) == 0)
3025                         reply = do_write(fsg);
3026                 break;
3027
3028         case SC_WRITE_10:
3029                 fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]) << 9;
3030                 if ((reply = check_command(fsg, 10, DATA_DIR_FROM_HOST,
3031                                 (1<<1) | (0xf<<2) | (3<<7), 1,
3032                                 "WRITE(10)")) == 0)
3033                         reply = do_write(fsg);
3034                 break;
3035
3036         case SC_WRITE_12:
3037                 fsg->data_size_from_cmnd = get_be32(&fsg->cmnd[6]) << 9;
3038                 if ((reply = check_command(fsg, 12, DATA_DIR_FROM_HOST,
3039                                 (1<<1) | (0xf<<2) | (0xf<<6), 1,
3040                                 "WRITE(12)")) == 0)
3041                         reply = do_write(fsg);
3042                 break;
3043
3044         /* Some mandatory commands that we recognize but don't implement.
3045          * They don't mean much in this setting.  It's left as an exercise
3046          * for anyone interested to implement RESERVE and RELEASE in terms
3047          * of Posix locks. */
3048         case SC_FORMAT_UNIT:
3049         case SC_RELEASE:
3050         case SC_RESERVE:
3051         case SC_SEND_DIAGNOSTIC:
3052                 // Fall through
3053
3054         default:
3055  unknown_cmnd:
3056                 fsg->data_size_from_cmnd = 0;
3057                 sprintf(unknown, "Unknown x%02x", fsg->cmnd[0]);
3058                 if ((reply = check_command(fsg, fsg->cmnd_size,
3059                              &