7dbbd1a911889c8e9c35925b09871cfad644a070
[pandora-kernel.git] / drivers / usb / gadget / f_mass_storage.c
1 /*
2  * f_mass_storage.c -- Mass Storage USB Composite Function
3  *
4  * Copyright (C) 2003-2008 Alan Stern
5  * Copyright (C) 2009 Samsung Electronics
6  *                    Author: Michal Nazarewicz <m.nazarewicz@samsung.com>
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions, and the following disclaimer,
14  *    without modification.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. The names of the above-listed copyright holders may not be used
19  *    to endorse or promote products derived from this software without
20  *    specific prior written permission.
21  *
22  * ALTERNATIVELY, this software may be distributed under the terms of the
23  * GNU General Public License ("GPL") as published by the Free Software
24  * Foundation, either version 2 of that License or (at your option) any
25  * later version.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
28  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
29  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
31  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
32  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
33  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
34  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
35  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
36  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
37  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38  */
39
40 /*
41  * The Mass Storage Function acts as a USB Mass Storage device,
42  * appearing to the host as a disk drive or as a CD-ROM drive.  In
43  * addition to providing an example of a genuinely useful composite
44  * function for a USB device, it also illustrates a technique of
45  * double-buffering for increased throughput.
46  *
47  * Function supports multiple logical units (LUNs).  Backing storage
48  * for each LUN is provided by a regular file or a block device.
49  * Access for each LUN can be limited to read-only.  Moreover, the
50  * function can indicate that LUN is removable and/or CD-ROM.  (The
51  * later implies read-only access.)
52  *
53  * MSF is configured by specifying a fsg_config structure.  It has the
54  * following fields:
55  *
56  *      nluns           Number of LUNs function have (anywhere from 1
57  *                              to FSG_MAX_LUNS which is 8).
58  *      luns            An array of LUN configuration values.  This
59  *                              should be filled for each LUN that
60  *                              function will include (ie. for "nluns"
61  *                              LUNs).  Each element of the array has
62  *                              the following fields:
63  *      ->filename      The path to the backing file for the LUN.
64  *                              Required if LUN is not marked as
65  *                              removable.
66  *      ->ro            Flag specifying access to the LUN shall be
67  *                              read-only.  This is implied if CD-ROM
68  *                              emulation is enabled as well as when
69  *                              it was impossible to open "filename"
70  *                              in R/W mode.
71  *      ->removable     Flag specifying that LUN shall be indicated as
72  *                              being removable.
73  *      ->cdrom         Flag specifying that LUN shall be reported as
74  *                              being a CD-ROM.
75  *      ->nofua         Flag specifying that FUA flag in SCSI WRITE(10,12)
76  *                              commands for this LUN shall be ignored.
77  *
78  *      lun_name_format A printf-like format for names of the LUN
79  *                              devices.  This determines how the
80  *                              directory in sysfs will be named.
81  *                              Unless you are using several MSFs in
82  *                              a single gadget (as opposed to single
83  *                              MSF in many configurations) you may
84  *                              leave it as NULL (in which case
85  *                              "lun%d" will be used).  In the format
86  *                              you can use "%d" to index LUNs for
87  *                              MSF's with more than one LUN.  (Beware
88  *                              that there is only one integer given
89  *                              as an argument for the format and
90  *                              specifying invalid format may cause
91  *                              unspecified behaviour.)
92  *      thread_name     Name of the kernel thread process used by the
93  *                              MSF.  You can safely set it to NULL
94  *                              (in which case default "file-storage"
95  *                              will be used).
96  *
97  *      vendor_name
98  *      product_name
99  *      release         Information used as a reply to INQUIRY
100  *                              request.  To use default set to NULL,
101  *                              NULL, 0xffff respectively.  The first
102  *                              field should be 8 and the second 16
103  *                              characters or less.
104  *
105  *      can_stall       Set to permit function to halt bulk endpoints.
106  *                              Disabled on some USB devices known not
107  *                              to work correctly.  You should set it
108  *                              to true.
109  *
110  * If "removable" is not set for a LUN then a backing file must be
111  * specified.  If it is set, then NULL filename means the LUN's medium
112  * is not loaded (an empty string as "filename" in the fsg_config
113  * structure causes error).  The CD-ROM emulation includes a single
114  * data track and no audio tracks; hence there need be only one
115  * backing file per LUN.
116  *
117  *
118  * MSF includes support for module parameters.  If gadget using it
119  * decides to use it, the following module parameters will be
120  * available:
121  *
122  *      file=filename[,filename...]
123  *                      Names of the files or block devices used for
124  *                              backing storage.
125  *      ro=b[,b...]     Default false, boolean for read-only access.
126  *      removable=b[,b...]
127  *                      Default true, boolean for removable media.
128  *      cdrom=b[,b...]  Default false, boolean for whether to emulate
129  *                              a CD-ROM drive.
130  *      nofua=b[,b...]  Default false, booleans for ignore FUA flag
131  *                              in SCSI WRITE(10,12) commands
132  *      luns=N          Default N = number of filenames, number of
133  *                              LUNs to support.
134  *      stall           Default determined according to the type of
135  *                              USB device controller (usually true),
136  *                              boolean to permit the driver to halt
137  *                              bulk endpoints.
138  *
139  * The module parameters may be prefixed with some string.  You need
140  * to consult gadget's documentation or source to verify whether it is
141  * using those module parameters and if it does what are the prefixes
142  * (look for FSG_MODULE_PARAMETERS() macro usage, what's inside it is
143  * the prefix).
144  *
145  *
146  * Requirements are modest; only a bulk-in and a bulk-out endpoint are
147  * needed.  The memory requirement amounts to two 16K buffers, size
148  * configurable by a parameter.  Support is included for both
149  * full-speed and high-speed operation.
150  *
151  * Note that the driver is slightly non-portable in that it assumes a
152  * single memory/DMA buffer will be useable for bulk-in, bulk-out, and
153  * interrupt-in endpoints.  With most device controllers this isn't an
154  * issue, but there may be some with hardware restrictions that prevent
155  * a buffer from being used by more than one endpoint.
156  *
157  *
158  * The pathnames of the backing files and the ro settings are
159  * available in the attribute files "file" and "ro" in the lun<n> (or
160  * to be more precise in a directory which name comes from
161  * "lun_name_format" option!) subdirectory of the gadget's sysfs
162  * directory.  If the "removable" option is set, writing to these
163  * files will simulate ejecting/loading the medium (writing an empty
164  * line means eject) and adjusting a write-enable tab.  Changes to the
165  * ro setting are not allowed when the medium is loaded or if CD-ROM
166  * emulation is being used.
167  *
168  * When a LUN receive an "eject" SCSI request (Start/Stop Unit),
169  * if the LUN is removable, the backing file is released to simulate
170  * ejection.
171  *
172  *
173  * This function is heavily based on "File-backed Storage Gadget" by
174  * Alan Stern which in turn is heavily based on "Gadget Zero" by David
175  * Brownell.  The driver's SCSI command interface was based on the
176  * "Information technology - Small Computer System Interface - 2"
177  * document from X3T9.2 Project 375D, Revision 10L, 7-SEP-93,
178  * available at <http://www.t10.org/ftp/t10/drafts/s2/s2-r10l.pdf>.
179  * The single exception is opcode 0x23 (READ FORMAT CAPACITIES), which
180  * was based on the "Universal Serial Bus Mass Storage Class UFI
181  * Command Specification" document, Revision 1.0, December 14, 1998,
182  * available at
183  * <http://www.usb.org/developers/devclass_docs/usbmass-ufi10.pdf>.
184  */
185
186 /*
187  *                              Driver Design
188  *
189  * The MSF is fairly straightforward.  There is a main kernel
190  * thread that handles most of the work.  Interrupt routines field
191  * callbacks from the controller driver: bulk- and interrupt-request
192  * completion notifications, endpoint-0 events, and disconnect events.
193  * Completion events are passed to the main thread by wakeup calls.  Many
194  * ep0 requests are handled at interrupt time, but SetInterface,
195  * SetConfiguration, and device reset requests are forwarded to the
196  * thread in the form of "exceptions" using SIGUSR1 signals (since they
197  * should interrupt any ongoing file I/O operations).
198  *
199  * The thread's main routine implements the standard command/data/status
200  * parts of a SCSI interaction.  It and its subroutines are full of tests
201  * for pending signals/exceptions -- all this polling is necessary since
202  * the kernel has no setjmp/longjmp equivalents.  (Maybe this is an
203  * indication that the driver really wants to be running in userspace.)
204  * An important point is that so long as the thread is alive it keeps an
205  * open reference to the backing file.  This will prevent unmounting
206  * the backing file's underlying filesystem and could cause problems
207  * during system shutdown, for example.  To prevent such problems, the
208  * thread catches INT, TERM, and KILL signals and converts them into
209  * an EXIT exception.
210  *
211  * In normal operation the main thread is started during the gadget's
212  * fsg_bind() callback and stopped during fsg_unbind().  But it can
213  * also exit when it receives a signal, and there's no point leaving
214  * the gadget running when the thread is dead.  At of this moment, MSF
215  * provides no way to deregister the gadget when thread dies -- maybe
216  * a callback functions is needed.
217  *
218  * To provide maximum throughput, the driver uses a circular pipeline of
219  * buffer heads (struct fsg_buffhd).  In principle the pipeline can be
220  * arbitrarily long; in practice the benefits don't justify having more
221  * than 2 stages (i.e., double buffering).  But it helps to think of the
222  * pipeline as being a long one.  Each buffer head contains a bulk-in and
223  * a bulk-out request pointer (since the buffer can be used for both
224  * output and input -- directions always are given from the host's
225  * point of view) as well as a pointer to the buffer and various state
226  * variables.
227  *
228  * Use of the pipeline follows a simple protocol.  There is a variable
229  * (fsg->next_buffhd_to_fill) that points to the next buffer head to use.
230  * At any time that buffer head may still be in use from an earlier
231  * request, so each buffer head has a state variable indicating whether
232  * it is EMPTY, FULL, or BUSY.  Typical use involves waiting for the
233  * buffer head to be EMPTY, filling the buffer either by file I/O or by
234  * USB I/O (during which the buffer head is BUSY), and marking the buffer
235  * head FULL when the I/O is complete.  Then the buffer will be emptied
236  * (again possibly by USB I/O, during which it is marked BUSY) and
237  * finally marked EMPTY again (possibly by a completion routine).
238  *
239  * A module parameter tells the driver to avoid stalling the bulk
240  * endpoints wherever the transport specification allows.  This is
241  * necessary for some UDCs like the SuperH, which cannot reliably clear a
242  * halt on a bulk endpoint.  However, under certain circumstances the
243  * Bulk-only specification requires a stall.  In such cases the driver
244  * will halt the endpoint and set a flag indicating that it should clear
245  * the halt in software during the next device reset.  Hopefully this
246  * will permit everything to work correctly.  Furthermore, although the
247  * specification allows the bulk-out endpoint to halt when the host sends
248  * too much data, implementing this would cause an unavoidable race.
249  * The driver will always use the "no-stall" approach for OUT transfers.
250  *
251  * One subtle point concerns sending status-stage responses for ep0
252  * requests.  Some of these requests, such as device reset, can involve
253  * interrupting an ongoing file I/O operation, which might take an
254  * arbitrarily long time.  During that delay the host might give up on
255  * the original ep0 request and issue a new one.  When that happens the
256  * driver should not notify the host about completion of the original
257  * request, as the host will no longer be waiting for it.  So the driver
258  * assigns to each ep0 request a unique tag, and it keeps track of the
259  * tag value of the request associated with a long-running exception
260  * (device-reset, interface-change, or configuration-change).  When the
261  * exception handler is finished, the status-stage response is submitted
262  * only if the current ep0 request tag is equal to the exception request
263  * tag.  Thus only the most recently received ep0 request will get a
264  * status-stage response.
265  *
266  * Warning: This driver source file is too long.  It ought to be split up
267  * into a header file plus about 3 separate .c files, to handle the details
268  * of the Gadget, USB Mass Storage, and SCSI protocols.
269  */
270
271
272 /* #define VERBOSE_DEBUG */
273 /* #define DUMP_MSGS */
274
275 #include <linux/blkdev.h>
276 #include <linux/completion.h>
277 #include <linux/dcache.h>
278 #include <linux/delay.h>
279 #include <linux/device.h>
280 #include <linux/fcntl.h>
281 #include <linux/file.h>
282 #include <linux/fs.h>
283 #include <linux/kref.h>
284 #include <linux/kthread.h>
285 #include <linux/limits.h>
286 #include <linux/rwsem.h>
287 #include <linux/slab.h>
288 #include <linux/spinlock.h>
289 #include <linux/string.h>
290 #include <linux/freezer.h>
291 #include <linux/utsname.h>
292
293 #include <linux/usb/ch9.h>
294 #include <linux/usb/gadget.h>
295 #include <linux/usb/composite.h>
296
297 #include "gadget_chips.h"
298
299
300 /*------------------------------------------------------------------------*/
301
302 #define FSG_DRIVER_DESC         "Mass Storage Function"
303 #define FSG_DRIVER_VERSION      "2009/09/11"
304
305 static const char fsg_string_interface[] = "Mass Storage";
306
307 #define FSG_NO_INTR_EP 1
308 #define FSG_NO_DEVICE_STRINGS    1
309 #define FSG_NO_OTG               1
310 #define FSG_NO_INTR_EP           1
311
312 #include "storage_common.c"
313
314
315 /*-------------------------------------------------------------------------*/
316
317 struct fsg_dev;
318 struct fsg_common;
319
320 /* FSF callback functions */
321 struct fsg_operations {
322         /*
323          * Callback function to call when thread exits.  If no
324          * callback is set or it returns value lower then zero MSF
325          * will force eject all LUNs it operates on (including those
326          * marked as non-removable or with prevent_medium_removal flag
327          * set).
328          */
329         int (*thread_exits)(struct fsg_common *common);
330
331         /*
332          * Called prior to ejection.  Negative return means error,
333          * zero means to continue with ejection, positive means not to
334          * eject.
335          */
336         int (*pre_eject)(struct fsg_common *common,
337                          struct fsg_lun *lun, int num);
338         /*
339          * Called after ejection.  Negative return means error, zero
340          * or positive is just a success.
341          */
342         int (*post_eject)(struct fsg_common *common,
343                           struct fsg_lun *lun, int num);
344 };
345
346 /* Data shared by all the FSG instances. */
347 struct fsg_common {
348         struct usb_gadget       *gadget;
349         struct usb_composite_dev *cdev;
350         struct fsg_dev          *fsg, *new_fsg;
351         wait_queue_head_t       fsg_wait;
352
353         /* filesem protects: backing files in use */
354         struct rw_semaphore     filesem;
355
356         /* lock protects: state, all the req_busy's */
357         spinlock_t              lock;
358
359         struct usb_ep           *ep0;           /* Copy of gadget->ep0 */
360         struct usb_request      *ep0req;        /* Copy of cdev->req */
361         unsigned int            ep0_req_tag;
362
363         struct fsg_buffhd       *next_buffhd_to_fill;
364         struct fsg_buffhd       *next_buffhd_to_drain;
365         struct fsg_buffhd       *buffhds;
366
367         int                     cmnd_size;
368         u8                      cmnd[MAX_COMMAND_SIZE];
369
370         unsigned int            nluns;
371         unsigned int            lun;
372         struct fsg_lun          *luns;
373         struct fsg_lun          *curlun;
374
375         unsigned int            bulk_out_maxpacket;
376         enum fsg_state          state;          /* For exception handling */
377         unsigned int            exception_req_tag;
378
379         enum data_direction     data_dir;
380         u32                     data_size;
381         u32                     data_size_from_cmnd;
382         u32                     tag;
383         u32                     residue;
384         u32                     usb_amount_left;
385
386         unsigned int            can_stall:1;
387         unsigned int            free_storage_on_release:1;
388         unsigned int            phase_error:1;
389         unsigned int            short_packet_received:1;
390         unsigned int            bad_lun_okay:1;
391         unsigned int            running:1;
392
393         int                     thread_wakeup_needed;
394         struct completion       thread_notifier;
395         struct task_struct      *thread_task;
396
397         /* Callback functions. */
398         const struct fsg_operations     *ops;
399         /* Gadget's private data. */
400         void                    *private_data;
401
402         /*
403          * Vendor (8 chars), product (16 chars), release (4
404          * hexadecimal digits) and NUL byte
405          */
406         char inquiry_string[8 + 16 + 4 + 1];
407
408         struct kref             ref;
409 };
410
411 struct fsg_config {
412         unsigned nluns;
413         struct fsg_lun_config {
414                 const char *filename;
415                 char ro;
416                 char removable;
417                 char cdrom;
418                 char nofua;
419         } luns[FSG_MAX_LUNS];
420
421         const char              *lun_name_format;
422         const char              *thread_name;
423
424         /* Callback functions. */
425         const struct fsg_operations     *ops;
426         /* Gadget's private data. */
427         void                    *private_data;
428
429         const char *vendor_name;                /*  8 characters or less */
430         const char *product_name;               /* 16 characters or less */
431         u16 release;
432
433         char                    can_stall;
434 };
435
436 struct fsg_dev {
437         struct usb_function     function;
438         struct usb_gadget       *gadget;        /* Copy of cdev->gadget */
439         struct fsg_common       *common;
440
441         u16                     interface_number;
442
443         unsigned int            bulk_in_enabled:1;
444         unsigned int            bulk_out_enabled:1;
445
446         unsigned long           atomic_bitflags;
447 #define IGNORE_BULK_OUT         0
448
449         struct usb_ep           *bulk_in;
450         struct usb_ep           *bulk_out;
451 };
452
453 static inline int __fsg_is_set(struct fsg_common *common,
454                                const char *func, unsigned line)
455 {
456         if (common->fsg)
457                 return 1;
458         ERROR(common, "common->fsg is NULL in %s at %u\n", func, line);
459         WARN_ON(1);
460         return 0;
461 }
462
463 #define fsg_is_set(common) likely(__fsg_is_set(common, __func__, __LINE__))
464
465 static inline struct fsg_dev *fsg_from_func(struct usb_function *f)
466 {
467         return container_of(f, struct fsg_dev, function);
468 }
469
470 typedef void (*fsg_routine_t)(struct fsg_dev *);
471
472 static int exception_in_progress(struct fsg_common *common)
473 {
474         return common->state > FSG_STATE_IDLE;
475 }
476
477 /* Make bulk-out requests be divisible by the maxpacket size */
478 static void set_bulk_out_req_length(struct fsg_common *common,
479                                     struct fsg_buffhd *bh, unsigned int length)
480 {
481         unsigned int    rem;
482
483         bh->bulk_out_intended_length = length;
484         rem = length % common->bulk_out_maxpacket;
485         if (rem > 0)
486                 length += common->bulk_out_maxpacket - rem;
487         bh->outreq->length = length;
488 }
489
490
491 /*-------------------------------------------------------------------------*/
492
493 static int fsg_set_halt(struct fsg_dev *fsg, struct usb_ep *ep)
494 {
495         const char      *name;
496
497         if (ep == fsg->bulk_in)
498                 name = "bulk-in";
499         else if (ep == fsg->bulk_out)
500                 name = "bulk-out";
501         else
502                 name = ep->name;
503         DBG(fsg, "%s set halt\n", name);
504         return usb_ep_set_halt(ep);
505 }
506
507
508 /*-------------------------------------------------------------------------*/
509
510 /* These routines may be called in process context or in_irq */
511
512 /* Caller must hold fsg->lock */
513 static void wakeup_thread(struct fsg_common *common)
514 {
515         smp_wmb();      /* ensure the write of bh->state is complete */
516         /* Tell the main thread that something has happened */
517         common->thread_wakeup_needed = 1;
518         if (common->thread_task)
519                 wake_up_process(common->thread_task);
520 }
521
522 static void raise_exception(struct fsg_common *common, enum fsg_state new_state)
523 {
524         unsigned long           flags;
525
526         /*
527          * Do nothing if a higher-priority exception is already in progress.
528          * If a lower-or-equal priority exception is in progress, preempt it
529          * and notify the main thread by sending it a signal.
530          */
531         spin_lock_irqsave(&common->lock, flags);
532         if (common->state <= new_state) {
533                 common->exception_req_tag = common->ep0_req_tag;
534                 common->state = new_state;
535                 if (common->thread_task)
536                         send_sig_info(SIGUSR1, SEND_SIG_FORCED,
537                                       common->thread_task);
538         }
539         spin_unlock_irqrestore(&common->lock, flags);
540 }
541
542
543 /*-------------------------------------------------------------------------*/
544
545 static int ep0_queue(struct fsg_common *common)
546 {
547         int     rc;
548
549         rc = usb_ep_queue(common->ep0, common->ep0req, GFP_ATOMIC);
550         common->ep0->driver_data = common;
551         if (rc != 0 && rc != -ESHUTDOWN) {
552                 /* We can't do much more than wait for a reset */
553                 WARNING(common, "error in submission: %s --> %d\n",
554                         common->ep0->name, rc);
555         }
556         return rc;
557 }
558
559
560 /*-------------------------------------------------------------------------*/
561
562 /* Completion handlers. These always run in_irq. */
563
564 static void bulk_in_complete(struct usb_ep *ep, struct usb_request *req)
565 {
566         struct fsg_common       *common = ep->driver_data;
567         struct fsg_buffhd       *bh = req->context;
568
569         if (req->status || req->actual != req->length)
570                 DBG(common, "%s --> %d, %u/%u\n", __func__,
571                     req->status, req->actual, req->length);
572         if (req->status == -ECONNRESET)         /* Request was cancelled */
573                 usb_ep_fifo_flush(ep);
574
575         /* Hold the lock while we update the request and buffer states */
576         smp_wmb();
577         spin_lock(&common->lock);
578         bh->inreq_busy = 0;
579         bh->state = BUF_STATE_EMPTY;
580         wakeup_thread(common);
581         spin_unlock(&common->lock);
582 }
583
584 static void bulk_out_complete(struct usb_ep *ep, struct usb_request *req)
585 {
586         struct fsg_common       *common = ep->driver_data;
587         struct fsg_buffhd       *bh = req->context;
588
589         dump_msg(common, "bulk-out", req->buf, req->actual);
590         if (req->status || req->actual != bh->bulk_out_intended_length)
591                 DBG(common, "%s --> %d, %u/%u\n", __func__,
592                     req->status, req->actual, bh->bulk_out_intended_length);
593         if (req->status == -ECONNRESET)         /* Request was cancelled */
594                 usb_ep_fifo_flush(ep);
595
596         /* Hold the lock while we update the request and buffer states */
597         smp_wmb();
598         spin_lock(&common->lock);
599         bh->outreq_busy = 0;
600         bh->state = BUF_STATE_FULL;
601         wakeup_thread(common);
602         spin_unlock(&common->lock);
603 }
604
605 static int fsg_setup(struct usb_function *f,
606                      const struct usb_ctrlrequest *ctrl)
607 {
608         struct fsg_dev          *fsg = fsg_from_func(f);
609         struct usb_request      *req = fsg->common->ep0req;
610         u16                     w_index = le16_to_cpu(ctrl->wIndex);
611         u16                     w_value = le16_to_cpu(ctrl->wValue);
612         u16                     w_length = le16_to_cpu(ctrl->wLength);
613
614         if (!fsg_is_set(fsg->common))
615                 return -EOPNOTSUPP;
616
617         ++fsg->common->ep0_req_tag;     /* Record arrival of a new request */
618         req->context = NULL;
619         req->length = 0;
620         dump_msg(fsg, "ep0-setup", (u8 *) ctrl, sizeof(*ctrl));
621
622         switch (ctrl->bRequest) {
623
624         case USB_BULK_RESET_REQUEST:
625                 if (ctrl->bRequestType !=
626                     (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE))
627                         break;
628                 if (w_index != fsg->interface_number || w_value != 0 ||
629                                 w_length != 0)
630                         return -EDOM;
631
632                 /*
633                  * Raise an exception to stop the current operation
634                  * and reinitialize our state.
635                  */
636                 DBG(fsg, "bulk reset request\n");
637                 raise_exception(fsg->common, FSG_STATE_RESET);
638                 return DELAYED_STATUS;
639
640         case USB_BULK_GET_MAX_LUN_REQUEST:
641                 if (ctrl->bRequestType !=
642                     (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE))
643                         break;
644                 if (w_index != fsg->interface_number || w_value != 0 ||
645                                 w_length != 1)
646                         return -EDOM;
647                 VDBG(fsg, "get max LUN\n");
648                 *(u8 *)req->buf = fsg->common->nluns - 1;
649
650                 /* Respond with data/status */
651                 req->length = min((u16)1, w_length);
652                 return ep0_queue(fsg->common);
653         }
654
655         VDBG(fsg,
656              "unknown class-specific control req %02x.%02x v%04x i%04x l%u\n",
657              ctrl->bRequestType, ctrl->bRequest,
658              le16_to_cpu(ctrl->wValue), w_index, w_length);
659         return -EOPNOTSUPP;
660 }
661
662
663 /*-------------------------------------------------------------------------*/
664
665 /* All the following routines run in process context */
666
667 /* Use this for bulk or interrupt transfers, not ep0 */
668 static void start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
669                            struct usb_request *req, int *pbusy,
670                            enum fsg_buffer_state *state)
671 {
672         int     rc;
673
674         if (ep == fsg->bulk_in)
675                 dump_msg(fsg, "bulk-in", req->buf, req->length);
676
677         spin_lock_irq(&fsg->common->lock);
678         *pbusy = 1;
679         *state = BUF_STATE_BUSY;
680         spin_unlock_irq(&fsg->common->lock);
681         rc = usb_ep_queue(ep, req, GFP_KERNEL);
682         if (rc != 0) {
683                 *pbusy = 0;
684                 *state = BUF_STATE_EMPTY;
685
686                 /* We can't do much more than wait for a reset */
687
688                 /*
689                  * Note: currently the net2280 driver fails zero-length
690                  * submissions if DMA is enabled.
691                  */
692                 if (rc != -ESHUTDOWN &&
693                     !(rc == -EOPNOTSUPP && req->length == 0))
694                         WARNING(fsg, "error in submission: %s --> %d\n",
695                                 ep->name, rc);
696         }
697 }
698
699 static bool start_in_transfer(struct fsg_common *common, struct fsg_buffhd *bh)
700 {
701         if (!fsg_is_set(common))
702                 return false;
703         start_transfer(common->fsg, common->fsg->bulk_in,
704                        bh->inreq, &bh->inreq_busy, &bh->state);
705         return true;
706 }
707
708 static bool start_out_transfer(struct fsg_common *common, struct fsg_buffhd *bh)
709 {
710         if (!fsg_is_set(common))
711                 return false;
712         start_transfer(common->fsg, common->fsg->bulk_out,
713                        bh->outreq, &bh->outreq_busy, &bh->state);
714         return true;
715 }
716
717 static int sleep_thread(struct fsg_common *common)
718 {
719         int     rc = 0;
720
721         /* Wait until a signal arrives or we are woken up */
722         for (;;) {
723                 try_to_freeze();
724                 set_current_state(TASK_INTERRUPTIBLE);
725                 if (signal_pending(current)) {
726                         rc = -EINTR;
727                         break;
728                 }
729                 if (common->thread_wakeup_needed)
730                         break;
731                 schedule();
732         }
733         __set_current_state(TASK_RUNNING);
734         common->thread_wakeup_needed = 0;
735         smp_rmb();      /* ensure the latest bh->state is visible */
736         return rc;
737 }
738
739
740 /*-------------------------------------------------------------------------*/
741
742 static int do_read(struct fsg_common *common)
743 {
744         struct fsg_lun          *curlun = common->curlun;
745         u32                     lba;
746         struct fsg_buffhd       *bh;
747         int                     rc;
748         u32                     amount_left;
749         loff_t                  file_offset, file_offset_tmp;
750         unsigned int            amount;
751         ssize_t                 nread;
752
753         /*
754          * Get the starting Logical Block Address and check that it's
755          * not too big.
756          */
757         if (common->cmnd[0] == READ_6)
758                 lba = get_unaligned_be24(&common->cmnd[1]);
759         else {
760                 lba = get_unaligned_be32(&common->cmnd[2]);
761
762                 /*
763                  * We allow DPO (Disable Page Out = don't save data in the
764                  * cache) and FUA (Force Unit Access = don't read from the
765                  * cache), but we don't implement them.
766                  */
767                 if ((common->cmnd[1] & ~0x18) != 0) {
768                         curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
769                         return -EINVAL;
770                 }
771         }
772         if (lba >= curlun->num_sectors) {
773                 curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
774                 return -EINVAL;
775         }
776         file_offset = ((loff_t) lba) << curlun->blkbits;
777
778         /* Carry out the file reads */
779         amount_left = common->data_size_from_cmnd;
780         if (unlikely(amount_left == 0))
781                 return -EIO;            /* No default reply */
782
783         for (;;) {
784                 /*
785                  * Figure out how much we need to read:
786                  * Try to read the remaining amount.
787                  * But don't read more than the buffer size.
788                  * And don't try to read past the end of the file.
789                  */
790                 amount = min(amount_left, FSG_BUFLEN);
791                 amount = min((loff_t)amount,
792                              curlun->file_length - file_offset);
793
794                 /* Wait for the next buffer to become available */
795                 bh = common->next_buffhd_to_fill;
796                 while (bh->state != BUF_STATE_EMPTY) {
797                         rc = sleep_thread(common);
798                         if (rc)
799                                 return rc;
800                 }
801
802                 /*
803                  * If we were asked to read past the end of file,
804                  * end with an empty buffer.
805                  */
806                 if (amount == 0) {
807                         curlun->sense_data =
808                                         SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
809                         curlun->sense_data_info =
810                                         file_offset >> curlun->blkbits;
811                         curlun->info_valid = 1;
812                         bh->inreq->length = 0;
813                         bh->state = BUF_STATE_FULL;
814                         break;
815                 }
816
817                 /* Perform the read */
818                 file_offset_tmp = file_offset;
819                 nread = vfs_read(curlun->filp,
820                                  (char __user *)bh->buf,
821                                  amount, &file_offset_tmp);
822                 VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
823                       (unsigned long long)file_offset, (int)nread);
824                 if (signal_pending(current))
825                         return -EINTR;
826
827                 if (nread < 0) {
828                         LDBG(curlun, "error in file read: %d\n", (int)nread);
829                         nread = 0;
830                 } else if (nread < amount) {
831                         LDBG(curlun, "partial file read: %d/%u\n",
832                              (int)nread, amount);
833                         nread = round_down(nread, curlun->blksize);
834                 }
835                 file_offset  += nread;
836                 amount_left  -= nread;
837                 common->residue -= nread;
838
839                 /*
840                  * Except at the end of the transfer, nread will be
841                  * equal to the buffer size, which is divisible by the
842                  * bulk-in maxpacket size.
843                  */
844                 bh->inreq->length = nread;
845                 bh->state = BUF_STATE_FULL;
846
847                 /* If an error occurred, report it and its position */
848                 if (nread < amount) {
849                         curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
850                         curlun->sense_data_info =
851                                         file_offset >> curlun->blkbits;
852                         curlun->info_valid = 1;
853                         break;
854                 }
855
856                 if (amount_left == 0)
857                         break;          /* No more left to read */
858
859                 /* Send this buffer and go read some more */
860                 bh->inreq->zero = 0;
861                 if (!start_in_transfer(common, bh))
862                         /* Don't know what to do if common->fsg is NULL */
863                         return -EIO;
864                 common->next_buffhd_to_fill = bh->next;
865         }
866
867         return -EIO;            /* No default reply */
868 }
869
870
871 /*-------------------------------------------------------------------------*/
872
873 static int do_write(struct fsg_common *common)
874 {
875         struct fsg_lun          *curlun = common->curlun;
876         u32                     lba;
877         struct fsg_buffhd       *bh;
878         int                     get_some_more;
879         u32                     amount_left_to_req, amount_left_to_write;
880         loff_t                  usb_offset, file_offset, file_offset_tmp;
881         unsigned int            amount;
882         ssize_t                 nwritten;
883         int                     rc;
884
885         if (curlun->ro) {
886                 curlun->sense_data = SS_WRITE_PROTECTED;
887                 return -EINVAL;
888         }
889         spin_lock(&curlun->filp->f_lock);
890         curlun->filp->f_flags &= ~O_SYNC;       /* Default is not to wait */
891         spin_unlock(&curlun->filp->f_lock);
892
893         /*
894          * Get the starting Logical Block Address and check that it's
895          * not too big
896          */
897         if (common->cmnd[0] == WRITE_6)
898                 lba = get_unaligned_be24(&common->cmnd[1]);
899         else {
900                 lba = get_unaligned_be32(&common->cmnd[2]);
901
902                 /*
903                  * We allow DPO (Disable Page Out = don't save data in the
904                  * cache) and FUA (Force Unit Access = write directly to the
905                  * medium).  We don't implement DPO; we implement FUA by
906                  * performing synchronous output.
907                  */
908                 if (common->cmnd[1] & ~0x18) {
909                         curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
910                         return -EINVAL;
911                 }
912                 if (!curlun->nofua && (common->cmnd[1] & 0x08)) { /* FUA */
913                         spin_lock(&curlun->filp->f_lock);
914                         curlun->filp->f_flags |= O_SYNC;
915                         spin_unlock(&curlun->filp->f_lock);
916                 }
917         }
918         if (lba >= curlun->num_sectors) {
919                 curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
920                 return -EINVAL;
921         }
922
923         /* Carry out the file writes */
924         get_some_more = 1;
925         file_offset = usb_offset = ((loff_t) lba) << curlun->blkbits;
926         amount_left_to_req = common->data_size_from_cmnd;
927         amount_left_to_write = common->data_size_from_cmnd;
928
929         while (amount_left_to_write > 0) {
930
931                 /* Queue a request for more data from the host */
932                 bh = common->next_buffhd_to_fill;
933                 if (bh->state == BUF_STATE_EMPTY && get_some_more) {
934
935                         /*
936                          * Figure out how much we want to get:
937                          * Try to get the remaining amount,
938                          * but not more than the buffer size.
939                          */
940                         amount = min(amount_left_to_req, FSG_BUFLEN);
941
942                         /* Beyond the end of the backing file? */
943                         if (usb_offset >= curlun->file_length) {
944                                 get_some_more = 0;
945                                 curlun->sense_data =
946                                         SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
947                                 curlun->sense_data_info =
948                                         usb_offset >> curlun->blkbits;
949                                 curlun->info_valid = 1;
950                                 continue;
951                         }
952
953                         /* Get the next buffer */
954                         usb_offset += amount;
955                         common->usb_amount_left -= amount;
956                         amount_left_to_req -= amount;
957                         if (amount_left_to_req == 0)
958                                 get_some_more = 0;
959
960                         /*
961                          * Except at the end of the transfer, amount will be
962                          * equal to the buffer size, which is divisible by
963                          * the bulk-out maxpacket size.
964                          */
965                         set_bulk_out_req_length(common, bh, amount);
966                         if (!start_out_transfer(common, bh))
967                                 /* Dunno what to do if common->fsg is NULL */
968                                 return -EIO;
969                         common->next_buffhd_to_fill = bh->next;
970                         continue;
971                 }
972
973                 /* Write the received data to the backing file */
974                 bh = common->next_buffhd_to_drain;
975                 if (bh->state == BUF_STATE_EMPTY && !get_some_more)
976                         break;                  /* We stopped early */
977                 if (bh->state == BUF_STATE_FULL) {
978                         smp_rmb();
979                         common->next_buffhd_to_drain = bh->next;
980                         bh->state = BUF_STATE_EMPTY;
981
982                         /* Did something go wrong with the transfer? */
983                         if (bh->outreq->status != 0) {
984                                 curlun->sense_data = SS_COMMUNICATION_FAILURE;
985                                 curlun->sense_data_info =
986                                         file_offset >> curlun->blkbits;
987                                 curlun->info_valid = 1;
988                                 break;
989                         }
990
991                         amount = bh->outreq->actual;
992                         if (curlun->file_length - file_offset < amount) {
993                                 LERROR(curlun,
994                                        "write %u @ %llu beyond end %llu\n",
995                                        amount, (unsigned long long)file_offset,
996                                        (unsigned long long)curlun->file_length);
997                                 amount = curlun->file_length - file_offset;
998                         }
999
1000                         /* Don't accept excess data.  The spec doesn't say
1001                          * what to do in this case.  We'll ignore the error.
1002                          */
1003                         amount = min(amount, bh->bulk_out_intended_length);
1004
1005                         /* Don't write a partial block */
1006                         amount = round_down(amount, curlun->blksize);
1007                         if (amount == 0)
1008                                 goto empty_write;
1009
1010                         /* Perform the write */
1011                         file_offset_tmp = file_offset;
1012                         nwritten = vfs_write(curlun->filp,
1013                                              (char __user *)bh->buf,
1014                                              amount, &file_offset_tmp);
1015                         VLDBG(curlun, "file write %u @ %llu -> %d\n", amount,
1016                               (unsigned long long)file_offset, (int)nwritten);
1017                         if (signal_pending(current))
1018                                 return -EINTR;          /* Interrupted! */
1019
1020                         if (nwritten < 0) {
1021                                 LDBG(curlun, "error in file write: %d\n",
1022                                      (int)nwritten);
1023                                 nwritten = 0;
1024                         } else if (nwritten < amount) {
1025                                 LDBG(curlun, "partial file write: %d/%u\n",
1026                                      (int)nwritten, amount);
1027                                 nwritten = round_down(nwritten, curlun->blksize);
1028                         }
1029                         file_offset += nwritten;
1030                         amount_left_to_write -= nwritten;
1031                         common->residue -= nwritten;
1032
1033                         /* If an error occurred, report it and its position */
1034                         if (nwritten < amount) {
1035                                 curlun->sense_data = SS_WRITE_ERROR;
1036                                 curlun->sense_data_info =
1037                                         file_offset >> curlun->blkbits;
1038                                 curlun->info_valid = 1;
1039                                 break;
1040                         }
1041
1042  empty_write:
1043                         /* Did the host decide to stop early? */
1044                         if (bh->outreq->actual < bh->bulk_out_intended_length) {
1045                                 common->short_packet_received = 1;
1046                                 break;
1047                         }
1048                         continue;
1049                 }
1050
1051                 /* Wait for something to happen */
1052                 rc = sleep_thread(common);
1053                 if (rc)
1054                         return rc;
1055         }
1056
1057         return -EIO;            /* No default reply */
1058 }
1059
1060
1061 /*-------------------------------------------------------------------------*/
1062
1063 static int do_synchronize_cache(struct fsg_common *common)
1064 {
1065         struct fsg_lun  *curlun = common->curlun;
1066         int             rc;
1067
1068         /* We ignore the requested LBA and write out all file's
1069          * dirty data buffers. */
1070         rc = fsg_lun_fsync_sub(curlun);
1071         if (rc)
1072                 curlun->sense_data = SS_WRITE_ERROR;
1073         return 0;
1074 }
1075
1076
1077 /*-------------------------------------------------------------------------*/
1078
1079 static void invalidate_sub(struct fsg_lun *curlun)
1080 {
1081         struct file     *filp = curlun->filp;
1082         struct inode    *inode = filp->f_path.dentry->d_inode;
1083         unsigned long   rc;
1084
1085         rc = invalidate_mapping_pages(inode->i_mapping, 0, -1);
1086         VLDBG(curlun, "invalidate_mapping_pages -> %ld\n", rc);
1087 }
1088
1089 static int do_verify(struct fsg_common *common)
1090 {
1091         struct fsg_lun          *curlun = common->curlun;
1092         u32                     lba;
1093         u32                     verification_length;
1094         struct fsg_buffhd       *bh = common->next_buffhd_to_fill;
1095         loff_t                  file_offset, file_offset_tmp;
1096         u32                     amount_left;
1097         unsigned int            amount;
1098         ssize_t                 nread;
1099
1100         /*
1101          * Get the starting Logical Block Address and check that it's
1102          * not too big.
1103          */
1104         lba = get_unaligned_be32(&common->cmnd[2]);
1105         if (lba >= curlun->num_sectors) {
1106                 curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1107                 return -EINVAL;
1108         }
1109
1110         /*
1111          * We allow DPO (Disable Page Out = don't save data in the
1112          * cache) but we don't implement it.
1113          */
1114         if (common->cmnd[1] & ~0x10) {
1115                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1116                 return -EINVAL;
1117         }
1118
1119         verification_length = get_unaligned_be16(&common->cmnd[7]);
1120         if (unlikely(verification_length == 0))
1121                 return -EIO;            /* No default reply */
1122
1123         /* Prepare to carry out the file verify */
1124         amount_left = verification_length << curlun->blkbits;
1125         file_offset = ((loff_t) lba) << curlun->blkbits;
1126
1127         /* Write out all the dirty buffers before invalidating them */
1128         fsg_lun_fsync_sub(curlun);
1129         if (signal_pending(current))
1130                 return -EINTR;
1131
1132         invalidate_sub(curlun);
1133         if (signal_pending(current))
1134                 return -EINTR;
1135
1136         /* Just try to read the requested blocks */
1137         while (amount_left > 0) {
1138                 /*
1139                  * Figure out how much we need to read:
1140                  * Try to read the remaining amount, but not more than
1141                  * the buffer size.
1142                  * And don't try to read past the end of the file.
1143                  */
1144                 amount = min(amount_left, FSG_BUFLEN);
1145                 amount = min((loff_t)amount,
1146                              curlun->file_length - file_offset);
1147                 if (amount == 0) {
1148                         curlun->sense_data =
1149                                         SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1150                         curlun->sense_data_info =
1151                                 file_offset >> curlun->blkbits;
1152                         curlun->info_valid = 1;
1153                         break;
1154                 }
1155
1156                 /* Perform the read */
1157                 file_offset_tmp = file_offset;
1158                 nread = vfs_read(curlun->filp,
1159                                 (char __user *) bh->buf,
1160                                 amount, &file_offset_tmp);
1161                 VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
1162                                 (unsigned long long) file_offset,
1163                                 (int) nread);
1164                 if (signal_pending(current))
1165                         return -EINTR;
1166
1167                 if (nread < 0) {
1168                         LDBG(curlun, "error in file verify: %d\n", (int)nread);
1169                         nread = 0;
1170                 } else if (nread < amount) {
1171                         LDBG(curlun, "partial file verify: %d/%u\n",
1172                              (int)nread, amount);
1173                         nread = round_down(nread, curlun->blksize);
1174                 }
1175                 if (nread == 0) {
1176                         curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
1177                         curlun->sense_data_info =
1178                                 file_offset >> curlun->blkbits;
1179                         curlun->info_valid = 1;
1180                         break;
1181                 }
1182                 file_offset += nread;
1183                 amount_left -= nread;
1184         }
1185         return 0;
1186 }
1187
1188
1189 /*-------------------------------------------------------------------------*/
1190
1191 static int do_inquiry(struct fsg_common *common, struct fsg_buffhd *bh)
1192 {
1193         struct fsg_lun *curlun = common->curlun;
1194         u8      *buf = (u8 *) bh->buf;
1195
1196         if (!curlun) {          /* Unsupported LUNs are okay */
1197                 common->bad_lun_okay = 1;
1198                 memset(buf, 0, 36);
1199                 buf[0] = 0x7f;          /* Unsupported, no device-type */
1200                 buf[4] = 31;            /* Additional length */
1201                 return 36;
1202         }
1203
1204         buf[0] = curlun->cdrom ? TYPE_ROM : TYPE_DISK;
1205         buf[1] = curlun->removable ? 0x80 : 0;
1206         buf[2] = 2;             /* ANSI SCSI level 2 */
1207         buf[3] = 2;             /* SCSI-2 INQUIRY data format */
1208         buf[4] = 31;            /* Additional length */
1209         buf[5] = 0;             /* No special options */
1210         buf[6] = 0;
1211         buf[7] = 0;
1212         memcpy(buf + 8, common->inquiry_string, sizeof common->inquiry_string);
1213         return 36;
1214 }
1215
1216 static int do_request_sense(struct fsg_common *common, struct fsg_buffhd *bh)
1217 {
1218         struct fsg_lun  *curlun = common->curlun;
1219         u8              *buf = (u8 *) bh->buf;
1220         u32             sd, sdinfo;
1221         int             valid;
1222
1223         /*
1224          * From the SCSI-2 spec., section 7.9 (Unit attention condition):
1225          *
1226          * If a REQUEST SENSE command is received from an initiator
1227          * with a pending unit attention condition (before the target
1228          * generates the contingent allegiance condition), then the
1229          * target shall either:
1230          *   a) report any pending sense data and preserve the unit
1231          *      attention condition on the logical unit, or,
1232          *   b) report the unit attention condition, may discard any
1233          *      pending sense data, and clear the unit attention
1234          *      condition on the logical unit for that initiator.
1235          *
1236          * FSG normally uses option a); enable this code to use option b).
1237          */
1238 #if 0
1239         if (curlun && curlun->unit_attention_data != SS_NO_SENSE) {
1240                 curlun->sense_data = curlun->unit_attention_data;
1241                 curlun->unit_attention_data = SS_NO_SENSE;
1242         }
1243 #endif
1244
1245         if (!curlun) {          /* Unsupported LUNs are okay */
1246                 common->bad_lun_okay = 1;
1247                 sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
1248                 sdinfo = 0;
1249                 valid = 0;
1250         } else {
1251                 sd = curlun->sense_data;
1252                 sdinfo = curlun->sense_data_info;
1253                 valid = curlun->info_valid << 7;
1254                 curlun->sense_data = SS_NO_SENSE;
1255                 curlun->sense_data_info = 0;
1256                 curlun->info_valid = 0;
1257         }
1258
1259         memset(buf, 0, 18);
1260         buf[0] = valid | 0x70;                  /* Valid, current error */
1261         buf[2] = SK(sd);
1262         put_unaligned_be32(sdinfo, &buf[3]);    /* Sense information */
1263         buf[7] = 18 - 8;                        /* Additional sense length */
1264         buf[12] = ASC(sd);
1265         buf[13] = ASCQ(sd);
1266         return 18;
1267 }
1268
1269 static int do_read_capacity(struct fsg_common *common, struct fsg_buffhd *bh)
1270 {
1271         struct fsg_lun  *curlun = common->curlun;
1272         u32             lba = get_unaligned_be32(&common->cmnd[2]);
1273         int             pmi = common->cmnd[8];
1274         u8              *buf = (u8 *)bh->buf;
1275
1276         /* Check the PMI and LBA fields */
1277         if (pmi > 1 || (pmi == 0 && lba != 0)) {
1278                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1279                 return -EINVAL;
1280         }
1281
1282         put_unaligned_be32(curlun->num_sectors - 1, &buf[0]);
1283                                                 /* Max logical block */
1284         put_unaligned_be32(curlun->blksize, &buf[4]);/* Block length */
1285         return 8;
1286 }
1287
1288 static int do_read_header(struct fsg_common *common, struct fsg_buffhd *bh)
1289 {
1290         struct fsg_lun  *curlun = common->curlun;
1291         int             msf = common->cmnd[1] & 0x02;
1292         u32             lba = get_unaligned_be32(&common->cmnd[2]);
1293         u8              *buf = (u8 *)bh->buf;
1294
1295         if (common->cmnd[1] & ~0x02) {          /* Mask away MSF */
1296                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1297                 return -EINVAL;
1298         }
1299         if (lba >= curlun->num_sectors) {
1300                 curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1301                 return -EINVAL;
1302         }
1303
1304         memset(buf, 0, 8);
1305         buf[0] = 0x01;          /* 2048 bytes of user data, rest is EC */
1306         store_cdrom_address(&buf[4], msf, lba);
1307         return 8;
1308 }
1309
1310 static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
1311 {
1312         struct fsg_lun  *curlun = common->curlun;
1313         int             msf = common->cmnd[1] & 0x02;
1314         int             start_track = common->cmnd[6];
1315         u8              *buf = (u8 *)bh->buf;
1316
1317         if ((common->cmnd[1] & ~0x02) != 0 ||   /* Mask away MSF */
1318                         start_track > 1) {
1319                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1320                 return -EINVAL;
1321         }
1322
1323         memset(buf, 0, 20);
1324         buf[1] = (20-2);                /* TOC data length */
1325         buf[2] = 1;                     /* First track number */
1326         buf[3] = 1;                     /* Last track number */
1327         buf[5] = 0x16;                  /* Data track, copying allowed */
1328         buf[6] = 0x01;                  /* Only track is number 1 */
1329         store_cdrom_address(&buf[8], msf, 0);
1330
1331         buf[13] = 0x16;                 /* Lead-out track is data */
1332         buf[14] = 0xAA;                 /* Lead-out track number */
1333         store_cdrom_address(&buf[16], msf, curlun->num_sectors);
1334         return 20;
1335 }
1336
1337 static int do_mode_sense(struct fsg_common *common, struct fsg_buffhd *bh)
1338 {
1339         struct fsg_lun  *curlun = common->curlun;
1340         int             mscmnd = common->cmnd[0];
1341         u8              *buf = (u8 *) bh->buf;
1342         u8              *buf0 = buf;
1343         int             pc, page_code;
1344         int             changeable_values, all_pages;
1345         int             valid_page = 0;
1346         int             len, limit;
1347
1348         if ((common->cmnd[1] & ~0x08) != 0) {   /* Mask away DBD */
1349                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1350                 return -EINVAL;
1351         }
1352         pc = common->cmnd[2] >> 6;
1353         page_code = common->cmnd[2] & 0x3f;
1354         if (pc == 3) {
1355                 curlun->sense_data = SS_SAVING_PARAMETERS_NOT_SUPPORTED;
1356                 return -EINVAL;
1357         }
1358         changeable_values = (pc == 1);
1359         all_pages = (page_code == 0x3f);
1360
1361         /*
1362          * Write the mode parameter header.  Fixed values are: default
1363          * medium type, no cache control (DPOFUA), and no block descriptors.
1364          * The only variable value is the WriteProtect bit.  We will fill in
1365          * the mode data length later.
1366          */
1367         memset(buf, 0, 8);
1368         if (mscmnd == MODE_SENSE) {
1369                 buf[2] = (curlun->ro ? 0x80 : 0x00);            /* WP, DPOFUA */
1370                 buf += 4;
1371                 limit = 255;
1372         } else {                        /* MODE_SENSE_10 */
1373                 buf[3] = (curlun->ro ? 0x80 : 0x00);            /* WP, DPOFUA */
1374                 buf += 8;
1375                 limit = 65535;          /* Should really be FSG_BUFLEN */
1376         }
1377
1378         /* No block descriptors */
1379
1380         /*
1381          * The mode pages, in numerical order.  The only page we support
1382          * is the Caching page.
1383          */
1384         if (page_code == 0x08 || all_pages) {
1385                 valid_page = 1;
1386                 buf[0] = 0x08;          /* Page code */
1387                 buf[1] = 10;            /* Page length */
1388                 memset(buf+2, 0, 10);   /* None of the fields are changeable */
1389
1390                 if (!changeable_values) {
1391                         buf[2] = 0x04;  /* Write cache enable, */
1392                                         /* Read cache not disabled */
1393                                         /* No cache retention priorities */
1394                         put_unaligned_be16(0xffff, &buf[4]);
1395                                         /* Don't disable prefetch */
1396                                         /* Minimum prefetch = 0 */
1397                         put_unaligned_be16(0xffff, &buf[8]);
1398                                         /* Maximum prefetch */
1399                         put_unaligned_be16(0xffff, &buf[10]);
1400                                         /* Maximum prefetch ceiling */
1401                 }
1402                 buf += 12;
1403         }
1404
1405         /*
1406          * Check that a valid page was requested and the mode data length
1407          * isn't too long.
1408          */
1409         len = buf - buf0;
1410         if (!valid_page || len > limit) {
1411                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1412                 return -EINVAL;
1413         }
1414
1415         /*  Store the mode data length */
1416         if (mscmnd == MODE_SENSE)
1417                 buf0[0] = len - 1;
1418         else
1419                 put_unaligned_be16(len - 2, buf0);
1420         return len;
1421 }
1422
1423 static int do_start_stop(struct fsg_common *common)
1424 {
1425         struct fsg_lun  *curlun = common->curlun;
1426         int             loej, start;
1427
1428         if (!curlun) {
1429                 return -EINVAL;
1430         } else if (!curlun->removable) {
1431                 curlun->sense_data = SS_INVALID_COMMAND;
1432                 return -EINVAL;
1433         } else if ((common->cmnd[1] & ~0x01) != 0 || /* Mask away Immed */
1434                    (common->cmnd[4] & ~0x03) != 0) { /* Mask LoEj, Start */
1435                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1436                 return -EINVAL;
1437         }
1438
1439         loej  = common->cmnd[4] & 0x02;
1440         start = common->cmnd[4] & 0x01;
1441
1442         /*
1443          * Our emulation doesn't support mounting; the medium is
1444          * available for use as soon as it is loaded.
1445          */
1446         if (start) {
1447                 if (!fsg_lun_is_open(curlun)) {
1448                         curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
1449                         return -EINVAL;
1450                 }
1451                 return 0;
1452         }
1453
1454         /* Are we allowed to unload the media? */
1455         if (curlun->prevent_medium_removal) {
1456                 LDBG(curlun, "unload attempt prevented\n");
1457                 curlun->sense_data = SS_MEDIUM_REMOVAL_PREVENTED;
1458                 return -EINVAL;
1459         }
1460
1461         if (!loej)
1462                 return 0;
1463
1464         /* Simulate an unload/eject */
1465         if (common->ops && common->ops->pre_eject) {
1466                 int r = common->ops->pre_eject(common, curlun,
1467                                                curlun - common->luns);
1468                 if (unlikely(r < 0))
1469                         return r;
1470                 else if (r)
1471                         return 0;
1472         }
1473
1474         up_read(&common->filesem);
1475         down_write(&common->filesem);
1476         fsg_lun_close(curlun);
1477         up_write(&common->filesem);
1478         down_read(&common->filesem);
1479
1480         return common->ops && common->ops->post_eject
1481                 ? min(0, common->ops->post_eject(common, curlun,
1482                                                  curlun - common->luns))
1483                 : 0;
1484 }
1485
1486 static int do_prevent_allow(struct fsg_common *common)
1487 {
1488         struct fsg_lun  *curlun = common->curlun;
1489         int             prevent;
1490
1491         if (!common->curlun) {
1492                 return -EINVAL;
1493         } else if (!common->curlun->removable) {
1494                 common->curlun->sense_data = SS_INVALID_COMMAND;
1495                 return -EINVAL;
1496         }
1497
1498         prevent = common->cmnd[4] & 0x01;
1499         if ((common->cmnd[4] & ~0x01) != 0) {   /* Mask away Prevent */
1500                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1501                 return -EINVAL;
1502         }
1503
1504         if (curlun->prevent_medium_removal && !prevent)
1505                 fsg_lun_fsync_sub(curlun);
1506         curlun->prevent_medium_removal = prevent;
1507         return 0;
1508 }
1509
1510 static int do_read_format_capacities(struct fsg_common *common,
1511                         struct fsg_buffhd *bh)
1512 {
1513         struct fsg_lun  *curlun = common->curlun;
1514         u8              *buf = (u8 *) bh->buf;
1515
1516         buf[0] = buf[1] = buf[2] = 0;
1517         buf[3] = 8;     /* Only the Current/Maximum Capacity Descriptor */
1518         buf += 4;
1519
1520         put_unaligned_be32(curlun->num_sectors, &buf[0]);
1521                                                 /* Number of blocks */
1522         put_unaligned_be32(curlun->blksize, &buf[4]);/* Block length */
1523         buf[4] = 0x02;                          /* Current capacity */
1524         return 12;
1525 }
1526
1527 static int do_mode_select(struct fsg_common *common, struct fsg_buffhd *bh)
1528 {
1529         struct fsg_lun  *curlun = common->curlun;
1530
1531         /* We don't support MODE SELECT */
1532         if (curlun)
1533                 curlun->sense_data = SS_INVALID_COMMAND;
1534         return -EINVAL;
1535 }
1536
1537
1538 /*-------------------------------------------------------------------------*/
1539
1540 static int halt_bulk_in_endpoint(struct fsg_dev *fsg)
1541 {
1542         int     rc;
1543
1544         rc = fsg_set_halt(fsg, fsg->bulk_in);
1545         if (rc == -EAGAIN)
1546                 VDBG(fsg, "delayed bulk-in endpoint halt\n");
1547         while (rc != 0) {
1548                 if (rc != -EAGAIN) {
1549                         WARNING(fsg, "usb_ep_set_halt -> %d\n", rc);
1550                         rc = 0;
1551                         break;
1552                 }
1553
1554                 /* Wait for a short time and then try again */
1555                 if (msleep_interruptible(100) != 0)
1556                         return -EINTR;
1557                 rc = usb_ep_set_halt(fsg->bulk_in);
1558         }
1559         return rc;
1560 }
1561
1562 static int wedge_bulk_in_endpoint(struct fsg_dev *fsg)
1563 {
1564         int     rc;
1565
1566         DBG(fsg, "bulk-in set wedge\n");
1567         rc = usb_ep_set_wedge(fsg->bulk_in);
1568         if (rc == -EAGAIN)
1569                 VDBG(fsg, "delayed bulk-in endpoint wedge\n");
1570         while (rc != 0) {
1571                 if (rc != -EAGAIN) {
1572                         WARNING(fsg, "usb_ep_set_wedge -> %d\n", rc);
1573                         rc = 0;
1574                         break;
1575                 }
1576
1577                 /* Wait for a short time and then try again */
1578                 if (msleep_interruptible(100) != 0)
1579                         return -EINTR;
1580                 rc = usb_ep_set_wedge(fsg->bulk_in);
1581         }
1582         return rc;
1583 }
1584
1585 static int throw_away_data(struct fsg_common *common)
1586 {
1587         struct fsg_buffhd       *bh;
1588         u32                     amount;
1589         int                     rc;
1590
1591         for (bh = common->next_buffhd_to_drain;
1592              bh->state != BUF_STATE_EMPTY || common->usb_amount_left > 0;
1593              bh = common->next_buffhd_to_drain) {
1594
1595                 /* Throw away the data in a filled buffer */
1596                 if (bh->state == BUF_STATE_FULL) {
1597                         smp_rmb();
1598                         bh->state = BUF_STATE_EMPTY;
1599                         common->next_buffhd_to_drain = bh->next;
1600
1601                         /* A short packet or an error ends everything */
1602                         if (bh->outreq->actual < bh->bulk_out_intended_length ||
1603                             bh->outreq->status != 0) {
1604                                 raise_exception(common,
1605                                                 FSG_STATE_ABORT_BULK_OUT);
1606                                 return -EINTR;
1607                         }
1608                         continue;
1609                 }
1610
1611                 /* Try to submit another request if we need one */
1612                 bh = common->next_buffhd_to_fill;
1613                 if (bh->state == BUF_STATE_EMPTY
1614                  && common->usb_amount_left > 0) {
1615                         amount = min(common->usb_amount_left, FSG_BUFLEN);
1616
1617                         /*
1618                          * Except at the end of the transfer, amount will be
1619                          * equal to the buffer size, which is divisible by
1620                          * the bulk-out maxpacket size.
1621                          */
1622                         set_bulk_out_req_length(common, bh, amount);
1623                         if (!start_out_transfer(common, bh))
1624                                 /* Dunno what to do if common->fsg is NULL */
1625                                 return -EIO;
1626                         common->next_buffhd_to_fill = bh->next;
1627                         common->usb_amount_left -= amount;
1628                         continue;
1629                 }
1630
1631                 /* Otherwise wait for something to happen */
1632                 rc = sleep_thread(common);
1633                 if (rc)
1634                         return rc;
1635         }
1636         return 0;
1637 }
1638
1639 static int finish_reply(struct fsg_common *common)
1640 {
1641         struct fsg_buffhd       *bh = common->next_buffhd_to_fill;
1642         int                     rc = 0;
1643
1644         switch (common->data_dir) {
1645         case DATA_DIR_NONE:
1646                 break;                  /* Nothing to send */
1647
1648         /*
1649          * If we don't know whether the host wants to read or write,
1650          * this must be CB or CBI with an unknown command.  We mustn't
1651          * try to send or receive any data.  So stall both bulk pipes
1652          * if we can and wait for a reset.
1653          */
1654         case DATA_DIR_UNKNOWN:
1655                 if (!common->can_stall) {
1656                         /* Nothing */
1657                 } else if (fsg_is_set(common)) {
1658                         fsg_set_halt(common->fsg, common->fsg->bulk_out);
1659                         rc = halt_bulk_in_endpoint(common->fsg);
1660                 } else {
1661                         /* Don't know what to do if common->fsg is NULL */
1662                         rc = -EIO;
1663                 }
1664                 break;
1665
1666         /* All but the last buffer of data must have already been sent */
1667         case DATA_DIR_TO_HOST:
1668                 if (common->data_size == 0) {
1669                         /* Nothing to send */
1670
1671                 /* Don't know what to do if common->fsg is NULL */
1672                 } else if (!fsg_is_set(common)) {
1673                         rc = -EIO;
1674
1675                 /* If there's no residue, simply send the last buffer */
1676                 } else if (common->residue == 0) {
1677                         bh->inreq->zero = 0;
1678                         if (!start_in_transfer(common, bh))
1679                                 return -EIO;
1680                         common->next_buffhd_to_fill = bh->next;
1681
1682                 /*
1683                  * For Bulk-only, mark the end of the data with a short
1684                  * packet.  If we are allowed to stall, halt the bulk-in
1685                  * endpoint.  (Note: This violates the Bulk-Only Transport
1686                  * specification, which requires us to pad the data if we
1687                  * don't halt the endpoint.  Presumably nobody will mind.)
1688                  */
1689                 } else {
1690                         bh->inreq->zero = 1;
1691                         if (!start_in_transfer(common, bh))
1692                                 rc = -EIO;
1693                         common->next_buffhd_to_fill = bh->next;
1694                         if (common->can_stall)
1695                                 rc = halt_bulk_in_endpoint(common->fsg);
1696                 }
1697                 break;
1698
1699         /*
1700          * We have processed all we want from the data the host has sent.
1701          * There may still be outstanding bulk-out requests.
1702          */
1703         case DATA_DIR_FROM_HOST:
1704                 if (common->residue == 0) {
1705                         /* Nothing to receive */
1706
1707                 /* Did the host stop sending unexpectedly early? */
1708                 } else if (common->short_packet_received) {
1709                         raise_exception(common, FSG_STATE_ABORT_BULK_OUT);
1710                         rc = -EINTR;
1711
1712                 /*
1713                  * We haven't processed all the incoming data.  Even though
1714                  * we may be allowed to stall, doing so would cause a race.
1715                  * The controller may already have ACK'ed all the remaining
1716                  * bulk-out packets, in which case the host wouldn't see a
1717                  * STALL.  Not realizing the endpoint was halted, it wouldn't
1718                  * clear the halt -- leading to problems later on.
1719                  */
1720 #if 0
1721                 } else if (common->can_stall) {
1722                         if (fsg_is_set(common))
1723                                 fsg_set_halt(common->fsg,
1724                                              common->fsg->bulk_out);
1725                         raise_exception(common, FSG_STATE_ABORT_BULK_OUT);
1726                         rc = -EINTR;
1727 #endif
1728
1729                 /*
1730                  * We can't stall.  Read in the excess data and throw it
1731                  * all away.
1732                  */
1733                 } else {
1734                         rc = throw_away_data(common);
1735                 }
1736                 break;
1737         }
1738         return rc;
1739 }
1740
1741 static int send_status(struct fsg_common *common)
1742 {
1743         struct fsg_lun          *curlun = common->curlun;
1744         struct fsg_buffhd       *bh;
1745         struct bulk_cs_wrap     *csw;
1746         int                     rc;
1747         u8                      status = USB_STATUS_PASS;
1748         u32                     sd, sdinfo = 0;
1749
1750         /* Wait for the next buffer to become available */
1751         bh = common->next_buffhd_to_fill;
1752         while (bh->state != BUF_STATE_EMPTY) {
1753                 rc = sleep_thread(common);
1754                 if (rc)
1755                         return rc;
1756         }
1757
1758         if (curlun) {
1759                 sd = curlun->sense_data;
1760                 sdinfo = curlun->sense_data_info;
1761         } else if (common->bad_lun_okay)
1762                 sd = SS_NO_SENSE;
1763         else
1764                 sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
1765
1766         if (common->phase_error) {
1767                 DBG(common, "sending phase-error status\n");
1768                 status = USB_STATUS_PHASE_ERROR;
1769                 sd = SS_INVALID_COMMAND;
1770         } else if (sd != SS_NO_SENSE) {
1771                 DBG(common, "sending command-failure status\n");
1772                 status = USB_STATUS_FAIL;
1773                 VDBG(common, "  sense data: SK x%02x, ASC x%02x, ASCQ x%02x;"
1774                                 "  info x%x\n",
1775                                 SK(sd), ASC(sd), ASCQ(sd), sdinfo);
1776         }
1777
1778         /* Store and send the Bulk-only CSW */
1779         csw = (void *)bh->buf;
1780
1781         csw->Signature = cpu_to_le32(USB_BULK_CS_SIG);
1782         csw->Tag = common->tag;
1783         csw->Residue = cpu_to_le32(common->residue);
1784         csw->Status = status;
1785
1786         bh->inreq->length = USB_BULK_CS_WRAP_LEN;
1787         bh->inreq->zero = 0;
1788         if (!start_in_transfer(common, bh))
1789                 /* Don't know what to do if common->fsg is NULL */
1790                 return -EIO;
1791
1792         common->next_buffhd_to_fill = bh->next;
1793         return 0;
1794 }
1795
1796
1797 /*-------------------------------------------------------------------------*/
1798
1799 /*
1800  * Check whether the command is properly formed and whether its data size
1801  * and direction agree with the values we already have.
1802  */
1803 static int check_command(struct fsg_common *common, int cmnd_size,
1804                          enum data_direction data_dir, unsigned int mask,
1805                          int needs_medium, const char *name)
1806 {
1807         int                     i;
1808         int                     lun = common->cmnd[1] >> 5;
1809         static const char       dirletter[4] = {'u', 'o', 'i', 'n'};
1810         char                    hdlen[20];
1811         struct fsg_lun          *curlun;
1812
1813         hdlen[0] = 0;
1814         if (common->data_dir != DATA_DIR_UNKNOWN)
1815                 sprintf(hdlen, ", H%c=%u", dirletter[(int) common->data_dir],
1816                         common->data_size);
1817         VDBG(common, "SCSI command: %s;  Dc=%d, D%c=%u;  Hc=%d%s\n",
1818              name, cmnd_size, dirletter[(int) data_dir],
1819              common->data_size_from_cmnd, common->cmnd_size, hdlen);
1820
1821         /*
1822          * We can't reply at all until we know the correct data direction
1823          * and size.
1824          */
1825         if (common->data_size_from_cmnd == 0)
1826                 data_dir = DATA_DIR_NONE;
1827         if (common->data_size < common->data_size_from_cmnd) {
1828                 /*
1829                  * Host data size < Device data size is a phase error.
1830                  * Carry out the command, but only transfer as much as
1831                  * we are allowed.
1832                  */
1833                 common->data_size_from_cmnd = common->data_size;
1834                 common->phase_error = 1;
1835         }
1836         common->residue = common->data_size;
1837         common->usb_amount_left = common->data_size;
1838
1839         /* Conflicting data directions is a phase error */
1840         if (common->data_dir != data_dir && common->data_size_from_cmnd > 0) {
1841                 common->phase_error = 1;
1842                 return -EINVAL;
1843         }
1844
1845         /* Verify the length of the command itself */
1846         if (cmnd_size != common->cmnd_size) {
1847
1848                 /*
1849                  * Special case workaround: There are plenty of buggy SCSI
1850                  * implementations. Many have issues with cbw->Length
1851                  * field passing a wrong command size. For those cases we
1852                  * always try to work around the problem by using the length
1853                  * sent by the host side provided it is at least as large
1854                  * as the correct command length.
1855                  * Examples of such cases would be MS-Windows, which issues
1856                  * REQUEST SENSE with cbw->Length == 12 where it should
1857                  * be 6, and xbox360 issuing INQUIRY, TEST UNIT READY and
1858                  * REQUEST SENSE with cbw->Length == 10 where it should
1859                  * be 6 as well.
1860                  */
1861                 if (cmnd_size <= common->cmnd_size) {
1862                         DBG(common, "%s is buggy! Expected length %d "
1863                             "but we got %d\n", name,
1864                             cmnd_size, common->cmnd_size);
1865                         cmnd_size = common->cmnd_size;
1866                 } else {
1867                         common->phase_error = 1;
1868                         return -EINVAL;
1869                 }
1870         }
1871
1872         /* Check that the LUN values are consistent */
1873         if (common->lun != lun)
1874                 DBG(common, "using LUN %d from CBW, not LUN %d from CDB\n",
1875                     common->lun, lun);
1876
1877         /* Check the LUN */
1878         if (common->lun < common->nluns) {
1879                 curlun = &common->luns[common->lun];
1880                 common->curlun = curlun;
1881                 if (common->cmnd[0] != REQUEST_SENSE) {
1882                         curlun->sense_data = SS_NO_SENSE;
1883                         curlun->sense_data_info = 0;
1884                         curlun->info_valid = 0;
1885                 }
1886         } else {
1887                 common->curlun = NULL;
1888                 curlun = NULL;
1889                 common->bad_lun_okay = 0;
1890
1891                 /*
1892                  * INQUIRY and REQUEST SENSE commands are explicitly allowed
1893                  * to use unsupported LUNs; all others may not.
1894                  */
1895                 if (common->cmnd[0] != INQUIRY &&
1896                     common->cmnd[0] != REQUEST_SENSE) {
1897                         DBG(common, "unsupported LUN %d\n", common->lun);
1898                         return -EINVAL;
1899                 }
1900         }
1901
1902         /*
1903          * If a unit attention condition exists, only INQUIRY and
1904          * REQUEST SENSE commands are allowed; anything else must fail.
1905          */
1906         if (curlun && curlun->unit_attention_data != SS_NO_SENSE &&
1907             common->cmnd[0] != INQUIRY &&
1908             common->cmnd[0] != REQUEST_SENSE) {
1909                 curlun->sense_data = curlun->unit_attention_data;
1910                 curlun->unit_attention_data = SS_NO_SENSE;
1911                 return -EINVAL;
1912         }
1913
1914         /* Check that only command bytes listed in the mask are non-zero */
1915         common->cmnd[1] &= 0x1f;                        /* Mask away the LUN */
1916         for (i = 1; i < cmnd_size; ++i) {
1917                 if (common->cmnd[i] && !(mask & (1 << i))) {
1918                         if (curlun)
1919                                 curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1920                         return -EINVAL;
1921                 }
1922         }
1923
1924         /* If the medium isn't mounted and the command needs to access
1925          * it, return an error. */
1926         if (curlun && !fsg_lun_is_open(curlun) && needs_medium) {
1927                 curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
1928                 return -EINVAL;
1929         }
1930
1931         return 0;
1932 }
1933
1934 static int do_scsi_command(struct fsg_common *common)
1935 {
1936         struct fsg_buffhd       *bh;
1937         int                     rc;
1938         int                     reply = -EINVAL;
1939         int                     i;
1940         static char             unknown[16];
1941
1942         dump_cdb(common);
1943
1944         /* Wait for the next buffer to become available for data or status */
1945         bh = common->next_buffhd_to_fill;
1946         common->next_buffhd_to_drain = bh;
1947         while (bh->state != BUF_STATE_EMPTY) {
1948                 rc = sleep_thread(common);
1949                 if (rc)
1950                         return rc;
1951         }
1952         common->phase_error = 0;
1953         common->short_packet_received = 0;
1954
1955         down_read(&common->filesem);    /* We're using the backing file */
1956         switch (common->cmnd[0]) {
1957
1958         case INQUIRY:
1959                 common->data_size_from_cmnd = common->cmnd[4];
1960                 reply = check_command(common, 6, DATA_DIR_TO_HOST,
1961                                       (1<<4), 0,
1962                                       "INQUIRY");
1963                 if (reply == 0)
1964                         reply = do_inquiry(common, bh);
1965                 break;
1966
1967         case MODE_SELECT:
1968                 common->data_size_from_cmnd = common->cmnd[4];
1969                 reply = check_command(common, 6, DATA_DIR_FROM_HOST,
1970                                       (1<<1) | (1<<4), 0,
1971                                       "MODE SELECT(6)");
1972                 if (reply == 0)
1973                         reply = do_mode_select(common, bh);
1974                 break;
1975
1976         case MODE_SELECT_10:
1977                 common->data_size_from_cmnd =
1978                         get_unaligned_be16(&common->cmnd[7]);
1979                 reply = check_command(common, 10, DATA_DIR_FROM_HOST,
1980                                       (1<<1) | (3<<7), 0,
1981                                       "MODE SELECT(10)");
1982                 if (reply == 0)
1983                         reply = do_mode_select(common, bh);
1984                 break;
1985
1986         case MODE_SENSE:
1987                 common->data_size_from_cmnd = common->cmnd[4];
1988                 reply = check_command(common, 6, DATA_DIR_TO_HOST,
1989                                       (1<<1) | (1<<2) | (1<<4), 0,
1990                                       "MODE SENSE(6)");
1991                 if (reply == 0)
1992                         reply = do_mode_sense(common, bh);
1993                 break;
1994
1995         case MODE_SENSE_10:
1996                 common->data_size_from_cmnd =
1997                         get_unaligned_be16(&common->cmnd[7]);
1998                 reply = check_command(common, 10, DATA_DIR_TO_HOST,
1999                                       (1<<1) | (1<<2) | (3<<7), 0,
2000                                       "MODE SENSE(10)");
2001                 if (reply == 0)
2002                         reply = do_mode_sense(common, bh);
2003                 break;
2004
2005         case ALLOW_MEDIUM_REMOVAL:
2006                 common->data_size_from_cmnd = 0;
2007                 reply = check_command(common, 6, DATA_DIR_NONE,
2008                                       (1<<4), 0,
2009                                       "PREVENT-ALLOW MEDIUM REMOVAL");
2010                 if (reply == 0)
2011                         reply = do_prevent_allow(common);
2012                 break;
2013
2014         case READ_6:
2015                 i = common->cmnd[4];
2016                 common->data_size_from_cmnd = (i == 0 ? 256 : i) <<
2017                                 common->curlun->blkbits;
2018                 reply = check_command(common, 6, DATA_DIR_TO_HOST,
2019                                       (7<<1) | (1<<4), 1,
2020                                       "READ(6)");
2021                 if (reply == 0)
2022                         reply = do_read(common);
2023                 break;
2024
2025         case READ_10:
2026                 common->data_size_from_cmnd =
2027                                 get_unaligned_be16(&common->cmnd[7]) <<
2028                                                 common->curlun->blkbits;
2029                 reply = check_command(common, 10, DATA_DIR_TO_HOST,
2030                                       (1<<1) | (0xf<<2) | (3<<7), 1,
2031                                       "READ(10)");
2032                 if (reply == 0)
2033                         reply = do_read(common);
2034                 break;
2035
2036         case READ_12:
2037                 common->data_size_from_cmnd =
2038                                 get_unaligned_be32(&common->cmnd[6]) <<
2039                                                 common->curlun->blkbits;
2040                 reply = check_command(common, 12, DATA_DIR_TO_HOST,
2041                                       (1<<1) | (0xf<<2) | (0xf<<6), 1,
2042                                       "READ(12)");
2043                 if (reply == 0)
2044                         reply = do_read(common);
2045                 break;
2046
2047         case READ_CAPACITY:
2048                 common->data_size_from_cmnd = 8;
2049                 reply = check_command(common, 10, DATA_DIR_TO_HOST,
2050                                       (0xf<<2) | (1<<8), 1,
2051                                       "READ CAPACITY");
2052                 if (reply == 0)
2053                         reply = do_read_capacity(common, bh);
2054                 break;
2055
2056         case READ_HEADER:
2057                 if (!common->curlun || !common->curlun->cdrom)
2058                         goto unknown_cmnd;
2059                 common->data_size_from_cmnd =
2060                         get_unaligned_be16(&common->cmnd[7]);
2061                 reply = check_command(common, 10, DATA_DIR_TO_HOST,
2062                                       (3<<7) | (0x1f<<1), 1,
2063                                       "READ HEADER");
2064                 if (reply == 0)
2065                         reply = do_read_header(common, bh);
2066                 break;
2067
2068         case READ_TOC:
2069                 if (!common->curlun || !common->curlun->cdrom)
2070                         goto unknown_cmnd;
2071                 common->data_size_from_cmnd =
2072                         get_unaligned_be16(&common->cmnd[7]);
2073                 reply = check_command(common, 10, DATA_DIR_TO_HOST,
2074                                       (7<<6) | (1<<1), 1,
2075                                       "READ TOC");
2076                 if (reply == 0)
2077                         reply = do_read_toc(common, bh);
2078                 break;
2079
2080         case READ_FORMAT_CAPACITIES:
2081                 common->data_size_from_cmnd =
2082                         get_unaligned_be16(&common->cmnd[7]);
2083                 reply = check_command(common, 10, DATA_DIR_TO_HOST,
2084                                       (3<<7), 1,
2085                                       "READ FORMAT CAPACITIES");
2086                 if (reply == 0)
2087                         reply = do_read_format_capacities(common, bh);
2088                 break;
2089
2090         case REQUEST_SENSE:
2091                 common->data_size_from_cmnd = common->cmnd[4];
2092                 reply = check_command(common, 6, DATA_DIR_TO_HOST,
2093                                       (1<<4), 0,
2094                                       "REQUEST SENSE");
2095                 if (reply == 0)
2096                         reply = do_request_sense(common, bh);
2097                 break;
2098
2099         case START_STOP:
2100                 common->data_size_from_cmnd = 0;
2101                 reply = check_command(common, 6, DATA_DIR_NONE,
2102                                       (1<<1) | (1<<4), 0,
2103                                       "START-STOP UNIT");
2104                 if (reply == 0)
2105                         reply = do_start_stop(common);
2106                 break;
2107
2108         case SYNCHRONIZE_CACHE:
2109                 common->data_size_from_cmnd = 0;
2110                 reply = check_command(common, 10, DATA_DIR_NONE,
2111                                       (0xf<<2) | (3<<7), 1,
2112                                       "SYNCHRONIZE CACHE");
2113                 if (reply == 0)
2114                         reply = do_synchronize_cache(common);
2115                 break;
2116
2117         case TEST_UNIT_READY:
2118                 common->data_size_from_cmnd = 0;
2119                 reply = check_command(common, 6, DATA_DIR_NONE,
2120                                 0, 1,
2121                                 "TEST UNIT READY");
2122                 break;
2123
2124         /*
2125          * Although optional, this command is used by MS-Windows.  We
2126          * support a minimal version: BytChk must be 0.
2127          */
2128         case VERIFY:
2129                 common->data_size_from_cmnd = 0;
2130                 reply = check_command(common, 10, DATA_DIR_NONE,
2131                                       (1<<1) | (0xf<<2) | (3<<7), 1,
2132                                       "VERIFY");
2133                 if (reply == 0)
2134                         reply = do_verify(common);
2135                 break;
2136
2137         case WRITE_6:
2138                 i = common->cmnd[4];
2139                 common->data_size_from_cmnd = (i == 0 ? 256 : i) <<
2140                                         common->curlun->blkbits;
2141                 reply = check_command(common, 6, DATA_DIR_FROM_HOST,
2142                                       (7<<1) | (1<<4), 1,
2143                                       "WRITE(6)");
2144                 if (reply == 0)
2145                         reply = do_write(common);
2146                 break;
2147
2148         case WRITE_10:
2149                 common->data_size_from_cmnd =
2150                                 get_unaligned_be16(&common->cmnd[7]) <<
2151                                                 common->curlun->blkbits;
2152                 reply = check_command(common, 10, DATA_DIR_FROM_HOST,
2153                                       (1<<1) | (0xf<<2) | (3<<7), 1,
2154                                       "WRITE(10)");
2155                 if (reply == 0)
2156                         reply = do_write(common);
2157                 break;
2158
2159         case WRITE_12:
2160                 common->data_size_from_cmnd =
2161                                 get_unaligned_be32(&common->cmnd[6]) <<
2162                                                 common->curlun->blkbits;
2163                 reply = check_command(common, 12, DATA_DIR_FROM_HOST,
2164                                       (1<<1) | (0xf<<2) | (0xf<<6), 1,
2165                                       "WRITE(12)");
2166                 if (reply == 0)
2167                         reply = do_write(common);
2168                 break;
2169
2170         /*
2171          * Some mandatory commands that we recognize but don't implement.
2172          * They don't mean much in this setting.  It's left as an exercise
2173          * for anyone interested to implement RESERVE and RELEASE in terms
2174          * of Posix locks.
2175          */
2176         case FORMAT_UNIT:
2177         case RELEASE:
2178         case RESERVE:
2179         case SEND_DIAGNOSTIC:
2180                 /* Fall through */
2181
2182         default:
2183 unknown_cmnd:
2184                 common->data_size_from_cmnd = 0;
2185                 sprintf(unknown, "Unknown x%02x", common->cmnd[0]);
2186                 reply = check_command(common, common->cmnd_size,
2187                                       DATA_DIR_UNKNOWN, ~0, 0, unknown);
2188                 if (reply == 0) {
2189                         common->curlun->sense_data = SS_INVALID_COMMAND;
2190                         reply = -EINVAL;
2191                 }
2192                 break;
2193         }
2194         up_read(&common->filesem);
2195
2196         if (reply == -EINTR || signal_pending(current))
2197                 return -EINTR;
2198
2199         /* Set up the single reply buffer for finish_reply() */
2200         if (reply == -EINVAL)
2201                 reply = 0;              /* Error reply length */
2202         if (reply >= 0 && common->data_dir == DATA_DIR_TO_HOST) {
2203                 reply = min((u32)reply, common->data_size_from_cmnd);
2204                 bh->inreq->length = reply;
2205                 bh->state = BUF_STATE_FULL;
2206                 common->residue -= reply;
2207         }                               /* Otherwise it's already set */
2208
2209         return 0;
2210 }
2211
2212
2213 /*-------------------------------------------------------------------------*/
2214
2215 static int received_cbw(struct fsg_dev *fsg, struct fsg_buffhd *bh)
2216 {
2217         struct usb_request      *req = bh->outreq;
2218         struct fsg_bulk_cb_wrap *cbw = req->buf;
2219         struct fsg_common       *common = fsg->common;
2220
2221         /* Was this a real packet?  Should it be ignored? */
2222         if (req->status || test_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags))
2223                 return -EINVAL;
2224
2225         /* Is the CBW valid? */
2226         if (req->actual != USB_BULK_CB_WRAP_LEN ||
2227                         cbw->Signature != cpu_to_le32(
2228                                 USB_BULK_CB_SIG)) {
2229                 DBG(fsg, "invalid CBW: len %u sig 0x%x\n",
2230                                 req->actual,
2231                                 le32_to_cpu(cbw->Signature));
2232
2233                 /*
2234                  * The Bulk-only spec says we MUST stall the IN endpoint
2235                  * (6.6.1), so it's unavoidable.  It also says we must
2236                  * retain this state until the next reset, but there's
2237                  * no way to tell the controller driver it should ignore
2238                  * Clear-Feature(HALT) requests.
2239                  *
2240                  * We aren't required to halt the OUT endpoint; instead
2241                  * we can simply accept and discard any data received
2242                  * until the next reset.
2243                  */
2244                 wedge_bulk_in_endpoint(fsg);
2245                 set_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
2246                 return -EINVAL;
2247         }
2248
2249         /* Is the CBW meaningful? */
2250         if (cbw->Lun >= FSG_MAX_LUNS || cbw->Flags & ~USB_BULK_IN_FLAG ||
2251                         cbw->Length <= 0 || cbw->Length > MAX_COMMAND_SIZE) {
2252                 DBG(fsg, "non-meaningful CBW: lun = %u, flags = 0x%x, "
2253                                 "cmdlen %u\n",
2254                                 cbw->Lun, cbw->Flags, cbw->Length);
2255
2256                 /*
2257                  * We can do anything we want here, so let's stall the
2258                  * bulk pipes if we are allowed to.
2259                  */
2260                 if (common->can_stall) {
2261                         fsg_set_halt(fsg, fsg->bulk_out);
2262                         halt_bulk_in_endpoint(fsg);
2263                 }
2264                 return -EINVAL;
2265         }
2266
2267         /* Save the command for later */
2268         common->cmnd_size = cbw->Length;
2269         memcpy(common->cmnd, cbw->CDB, common->cmnd_size);
2270         if (cbw->Flags & USB_BULK_IN_FLAG)
2271                 common->data_dir = DATA_DIR_TO_HOST;
2272         else
2273                 common->data_dir = DATA_DIR_FROM_HOST;
2274         common->data_size = le32_to_cpu(cbw->DataTransferLength);
2275         if (common->data_size == 0)
2276                 common->data_dir = DATA_DIR_NONE;
2277         common->lun = cbw->Lun;
2278         common->tag = cbw->Tag;
2279         return 0;
2280 }
2281
2282 static int get_next_command(struct fsg_common *common)
2283 {
2284         struct fsg_buffhd       *bh;
2285         int                     rc = 0;
2286
2287         /* Wait for the next buffer to become available */
2288         bh = common->next_buffhd_to_fill;
2289         while (bh->state != BUF_STATE_EMPTY) {
2290                 rc = sleep_thread(common);
2291                 if (rc)
2292                         return rc;
2293         }
2294
2295         /* Queue a request to read a Bulk-only CBW */
2296         set_bulk_out_req_length(common, bh, USB_BULK_CB_WRAP_LEN);
2297         if (!start_out_transfer(common, bh))
2298                 /* Don't know what to do if common->fsg is NULL */
2299                 return -EIO;
2300
2301         /*
2302          * We will drain the buffer in software, which means we
2303          * can reuse it for the next filling.  No need to advance
2304          * next_buffhd_to_fill.
2305          */
2306
2307         /* Wait for the CBW to arrive */
2308         while (bh->state != BUF_STATE_FULL) {
2309                 rc = sleep_thread(common);
2310                 if (rc)
2311                         return rc;
2312         }
2313         smp_rmb();
2314         rc = fsg_is_set(common) ? received_cbw(common->fsg, bh) : -EIO;
2315         bh->state = BUF_STATE_EMPTY;
2316
2317         return rc;
2318 }
2319
2320
2321 /*-------------------------------------------------------------------------*/
2322
2323 static int alloc_request(struct fsg_common *common, struct usb_ep *ep,
2324                 struct usb_request **preq)
2325 {
2326         *preq = usb_ep_alloc_request(ep, GFP_ATOMIC);
2327         if (*preq)
2328                 return 0;
2329         ERROR(common, "can't allocate request for %s\n", ep->name);
2330         return -ENOMEM;
2331 }
2332
2333 /* Reset interface setting and re-init endpoint state (toggle etc). */
2334 static int do_set_interface(struct fsg_common *common, struct fsg_dev *new_fsg)
2335 {
2336         struct fsg_dev *fsg;
2337         int i, rc = 0;
2338
2339         if (common->running)
2340                 DBG(common, "reset interface\n");
2341
2342 reset:
2343         /* Deallocate the requests */
2344         if (common->fsg) {
2345                 fsg = common->fsg;
2346
2347                 for (i = 0; i < fsg_num_buffers; ++i) {
2348                         struct fsg_buffhd *bh = &common->buffhds[i];
2349
2350                         if (bh->inreq) {
2351                                 usb_ep_free_request(fsg->bulk_in, bh->inreq);
2352                                 bh->inreq = NULL;
2353                         }
2354                         if (bh->outreq) {
2355                                 usb_ep_free_request(fsg->bulk_out, bh->outreq);
2356                                 bh->outreq = NULL;
2357                         }
2358                 }
2359
2360                 /* Disable the endpoints */
2361                 if (fsg->bulk_in_enabled) {
2362                         usb_ep_disable(fsg->bulk_in);
2363                         fsg->bulk_in_enabled = 0;
2364                 }
2365                 if (fsg->bulk_out_enabled) {
2366                         usb_ep_disable(fsg->bulk_out);
2367                         fsg->bulk_out_enabled = 0;
2368                 }
2369
2370                 common->fsg = NULL;
2371                 wake_up(&common->fsg_wait);
2372         }
2373
2374         common->running = 0;
2375         if (!new_fsg || rc)
2376                 return rc;
2377
2378         common->fsg = new_fsg;
2379         fsg = common->fsg;
2380
2381         /* Enable the endpoints */
2382         rc = config_ep_by_speed(common->gadget, &(fsg->function), fsg->bulk_in);
2383         if (rc)
2384                 goto reset;
2385         rc = usb_ep_enable(fsg->bulk_in);
2386         if (rc)
2387                 goto reset;
2388         fsg->bulk_in->driver_data = common;
2389         fsg->bulk_in_enabled = 1;
2390
2391         rc = config_ep_by_speed(common->gadget, &(fsg->function),
2392                                 fsg->bulk_out);
2393         if (rc)
2394                 goto reset;
2395         rc = usb_ep_enable(fsg->bulk_out);
2396         if (rc)
2397                 goto reset;
2398         fsg->bulk_out->driver_data = common;
2399         fsg->bulk_out_enabled = 1;
2400         common->bulk_out_maxpacket = usb_endpoint_maxp(fsg->bulk_out->desc);
2401         clear_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
2402
2403         /* Allocate the requests */
2404         for (i = 0; i < fsg_num_buffers; ++i) {
2405                 struct fsg_buffhd       *bh = &common->buffhds[i];
2406
2407                 rc = alloc_request(common, fsg->bulk_in, &bh->inreq);
2408                 if (rc)
2409                         goto reset;
2410                 rc = alloc_request(common, fsg->bulk_out, &bh->outreq);
2411                 if (rc)
2412                         goto reset;
2413                 bh->inreq->buf = bh->outreq->buf = bh->buf;
2414                 bh->inreq->context = bh->outreq->context = bh;
2415                 bh->inreq->complete = bulk_in_complete;
2416                 bh->outreq->complete = bulk_out_complete;
2417         }
2418
2419         common->running = 1;
2420         for (i = 0; i < common->nluns; ++i)
2421                 common->luns[i].unit_attention_data = SS_RESET_OCCURRED;
2422         return rc;
2423 }
2424
2425
2426 /****************************** ALT CONFIGS ******************************/
2427
2428 static int fsg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
2429 {
2430         struct fsg_dev *fsg = fsg_from_func(f);
2431         fsg->common->new_fsg = fsg;
2432         raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
2433         return USB_GADGET_DELAYED_STATUS;
2434 }
2435
2436 static void fsg_disable(struct usb_function *f)
2437 {
2438         struct fsg_dev *fsg = fsg_from_func(f);
2439         fsg->common->new_fsg = NULL;
2440         raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
2441 }
2442
2443
2444 /*-------------------------------------------------------------------------*/
2445
2446 static void handle_exception(struct fsg_common *common)
2447 {
2448         siginfo_t               info;
2449         int                     i;
2450         struct fsg_buffhd       *bh;
2451         enum fsg_state          old_state;
2452         struct fsg_lun          *curlun;
2453         unsigned int            exception_req_tag;
2454
2455         /*
2456          * Clear the existing signals.  Anything but SIGUSR1 is converted
2457          * into a high-priority EXIT exception.
2458          */
2459         for (;;) {
2460                 int sig =
2461                         dequeue_signal_lock(current, &current->blocked, &info);
2462                 if (!sig)
2463                         break;
2464                 if (sig != SIGUSR1) {
2465                         if (common->state < FSG_STATE_EXIT)
2466                                 DBG(common, "Main thread exiting on signal\n");
2467                         raise_exception(common, FSG_STATE_EXIT);
2468                 }
2469         }
2470
2471         /* Cancel all the pending transfers */
2472         if (likely(common->fsg)) {
2473                 for (i = 0; i < fsg_num_buffers; ++i) {
2474                         bh = &common->buffhds[i];
2475                         if (bh->inreq_busy)
2476                                 usb_ep_dequeue(common->fsg->bulk_in, bh->inreq);
2477                         if (bh->outreq_busy)
2478                                 usb_ep_dequeue(common->fsg->bulk_out,
2479                                                bh->outreq);
2480                 }
2481
2482                 /* Wait until everything is idle */
2483                 for (;;) {
2484                         int num_active = 0;
2485                         for (i = 0; i < fsg_num_buffers; ++i) {
2486                                 bh = &common->buffhds[i];
2487                                 num_active += bh->inreq_busy + bh->outreq_busy;
2488                         }
2489                         if (num_active == 0)
2490                                 break;
2491                         if (sleep_thread(common))
2492                                 return;
2493                 }
2494
2495                 /* Clear out the controller's fifos */
2496                 if (common->fsg->bulk_in_enabled)
2497                         usb_ep_fifo_flush(common->fsg->bulk_in);
2498                 if (common->fsg->bulk_out_enabled)
2499                         usb_ep_fifo_flush(common->fsg->bulk_out);
2500         }
2501
2502         /*
2503          * Reset the I/O buffer states and pointers, the SCSI
2504          * state, and the exception.  Then invoke the handler.
2505          */
2506         spin_lock_irq(&common->lock);
2507
2508         for (i = 0; i < fsg_num_buffers; ++i) {
2509                 bh = &common->buffhds[i];
2510                 bh->state = BUF_STATE_EMPTY;
2511         }
2512         common->next_buffhd_to_fill = &common->buffhds[0];
2513         common->next_buffhd_to_drain = &common->buffhds[0];
2514         exception_req_tag = common->exception_req_tag;
2515         old_state = common->state;
2516
2517         if (old_state == FSG_STATE_ABORT_BULK_OUT)
2518                 common->state = FSG_STATE_STATUS_PHASE;
2519         else {
2520                 for (i = 0; i < common->nluns; ++i) {
2521                         curlun = &common->luns[i];
2522                         curlun->prevent_medium_removal = 0;
2523                         curlun->sense_data = SS_NO_SENSE;
2524                         curlun->unit_attention_data = SS_NO_SENSE;
2525                         curlun->sense_data_info = 0;
2526                         curlun->info_valid = 0;
2527                 }
2528                 common->state = FSG_STATE_IDLE;
2529         }
2530         spin_unlock_irq(&common->lock);
2531
2532         /* Carry out any extra actions required for the exception */
2533         switch (old_state) {
2534         case FSG_STATE_ABORT_BULK_OUT:
2535                 send_status(common);
2536                 spin_lock_irq(&common->lock);
2537                 if (common->state == FSG_STATE_STATUS_PHASE)
2538                         common->state = FSG_STATE_IDLE;
2539                 spin_unlock_irq(&common->lock);
2540                 break;
2541
2542         case FSG_STATE_RESET:
2543                 /*
2544                  * In case we were forced against our will to halt a
2545                  * bulk endpoint, clear the halt now.  (The SuperH UDC
2546                  * requires this.)
2547                  */
2548                 if (!fsg_is_set(common))
2549                         break;
2550                 if (test_and_clear_bit(IGNORE_BULK_OUT,
2551                                        &common->fsg->atomic_bitflags))
2552                         usb_ep_clear_halt(common->fsg->bulk_in);
2553
2554                 if (common->ep0_req_tag == exception_req_tag)
2555                         ep0_queue(common);      /* Complete the status stage */
2556
2557                 /*
2558                  * Technically this should go here, but it would only be
2559                  * a waste of time.  Ditto for the INTERFACE_CHANGE and
2560                  * CONFIG_CHANGE cases.
2561                  */
2562                 /* for (i = 0; i < common->nluns; ++i) */
2563                 /*      common->luns[i].unit_attention_data = */
2564                 /*              SS_RESET_OCCURRED;  */
2565                 break;
2566
2567         case FSG_STATE_CONFIG_CHANGE:
2568                 do_set_interface(common, common->new_fsg);
2569                 if (common->new_fsg)
2570                         usb_composite_setup_continue(common->cdev);
2571                 break;
2572
2573         case FSG_STATE_EXIT:
2574         case FSG_STATE_TERMINATED:
2575                 do_set_interface(common, NULL);         /* Free resources */
2576                 spin_lock_irq(&common->lock);
2577                 common->state = FSG_STATE_TERMINATED;   /* Stop the thread */
2578                 spin_unlock_irq(&common->lock);
2579                 break;
2580
2581         case FSG_STATE_INTERFACE_CHANGE:
2582         case FSG_STATE_DISCONNECT:
2583         case FSG_STATE_COMMAND_PHASE:
2584         case FSG_STATE_DATA_PHASE:
2585         case FSG_STATE_STATUS_PHASE:
2586         case FSG_STATE_IDLE:
2587                 break;
2588         }
2589 }
2590
2591
2592 /*-------------------------------------------------------------------------*/
2593
2594 static int fsg_main_thread(void *common_)
2595 {
2596         struct fsg_common       *common = common_;
2597
2598         /*
2599          * Allow the thread to be killed by a signal, but set the signal mask
2600          * to block everything but INT, TERM, KILL, and USR1.
2601          */
2602         allow_signal(SIGINT);
2603         allow_signal(SIGTERM);
2604         allow_signal(SIGKILL);
2605         allow_signal(SIGUSR1);
2606
2607         /* Allow the thread to be frozen */
2608         set_freezable();
2609
2610         /*
2611          * Arrange for userspace references to be interpreted as kernel
2612          * pointers.  That way we can pass a kernel pointer to a routine
2613          * that expects a __user pointer and it will work okay.
2614          */
2615         set_fs(get_ds());
2616
2617         /* The main loop */
2618         while (common->state != FSG_STATE_TERMINATED) {
2619                 if (exception_in_progress(common) || signal_pending(current)) {
2620                         handle_exception(common);
2621                         continue;
2622                 }
2623
2624                 if (!common->running) {
2625                         sleep_thread(common);
2626                         continue;
2627                 }
2628
2629                 if (get_next_command(common))
2630                         continue;
2631
2632                 spin_lock_irq(&common->lock);
2633                 if (!exception_in_progress(common))
2634                         common->state = FSG_STATE_DATA_PHASE;
2635                 spin_unlock_irq(&common->lock);
2636
2637                 if (do_scsi_command(common) || finish_reply(common))
2638                         continue;
2639
2640                 spin_lock_irq(&common->lock);
2641                 if (!exception_in_progress(common))
2642                         common->state = FSG_STATE_STATUS_PHASE;
2643                 spin_unlock_irq(&common->lock);
2644
2645                 if (send_status(common))
2646                         continue;
2647
2648                 spin_lock_irq(&common->lock);
2649                 if (!exception_in_progress(common))
2650                         common->state = FSG_STATE_IDLE;
2651                 spin_unlock_irq(&common->lock);
2652         }
2653
2654         spin_lock_irq(&common->lock);
2655         common->thread_task = NULL;
2656         spin_unlock_irq(&common->lock);
2657
2658         if (!common->ops || !common->ops->thread_exits
2659          || common->ops->thread_exits(common) < 0) {
2660                 struct fsg_lun *curlun = common->luns;
2661                 unsigned i = common->nluns;
2662
2663                 down_write(&common->filesem);
2664                 for (; i--; ++curlun) {
2665                         if (!fsg_lun_is_open(curlun))
2666                                 continue;
2667
2668                         fsg_lun_close(curlun);
2669                         curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
2670                 }
2671                 up_write(&common->filesem);
2672         }
2673
2674         /* Let fsg_unbind() know the thread has exited */
2675         complete_and_exit(&common->thread_notifier, 0);
2676 }
2677
2678
2679 /*************************** DEVICE ATTRIBUTES ***************************/
2680
2681 /* Write permission is checked per LUN in store_*() functions. */
2682 static DEVICE_ATTR(ro, 0644, fsg_show_ro, fsg_store_ro);
2683 static DEVICE_ATTR(nofua, 0644, fsg_show_nofua, fsg_store_nofua);
2684 static DEVICE_ATTR(file, 0644, fsg_show_file, fsg_store_file);
2685
2686
2687 /****************************** FSG COMMON ******************************/
2688
2689 static void fsg_common_release(struct kref *ref);
2690
2691 static void fsg_lun_release(struct device *dev)
2692 {
2693         /* Nothing needs to be done */
2694 }
2695
2696 static inline void fsg_common_get(struct fsg_common *common)
2697 {
2698         kref_get(&common->ref);
2699 }
2700
2701 static inline void fsg_common_put(struct fsg_common *common)
2702 {
2703         kref_put(&common->ref, fsg_common_release);
2704 }
2705
2706 static struct fsg_common *fsg_common_init(struct fsg_common *common,
2707                                           struct usb_composite_dev *cdev,
2708                                           struct fsg_config *cfg)
2709 {
2710         struct usb_gadget *gadget = cdev->gadget;
2711         struct fsg_buffhd *bh;
2712         struct fsg_lun *curlun;
2713         struct fsg_lun_config *lcfg;
2714         int nluns, i, rc;
2715         char *pathbuf;
2716
2717         rc = fsg_num_buffers_validate();
2718         if (rc != 0)
2719                 return ERR_PTR(rc);
2720
2721         /* Find out how many LUNs there should be */
2722         nluns = cfg->nluns;
2723         if (nluns < 1 || nluns > FSG_MAX_LUNS) {
2724                 dev_err(&gadget->dev, "invalid number of LUNs: %u\n", nluns);
2725                 return ERR_PTR(-EINVAL);
2726         }
2727
2728         /* Allocate? */
2729         if (!common) {
2730                 common = kzalloc(sizeof *common, GFP_KERNEL);
2731                 if (!common)
2732                         return ERR_PTR(-ENOMEM);
2733                 common->free_storage_on_release = 1;
2734         } else {
2735                 memset(common, 0, sizeof *common);
2736                 common->free_storage_on_release = 0;
2737         }
2738
2739         common->buffhds = kcalloc(fsg_num_buffers,
2740                                   sizeof *(common->buffhds), GFP_KERNEL);
2741         if (!common->buffhds) {
2742                 if (common->free_storage_on_release)
2743                         kfree(common);
2744                 return ERR_PTR(-ENOMEM);
2745         }
2746
2747         common->ops = cfg->ops;
2748         common->private_data = cfg->private_data;
2749
2750         common->gadget = gadget;
2751         common->ep0 = gadget->ep0;
2752         common->ep0req = cdev->req;
2753         common->cdev = cdev;
2754
2755         /* Maybe allocate device-global string IDs, and patch descriptors */
2756         if (fsg_strings[FSG_STRING_INTERFACE].id == 0) {
2757                 rc = usb_string_id(cdev);
2758                 if (unlikely(rc < 0))
2759                         goto error_release;
2760                 fsg_strings[FSG_STRING_INTERFACE].id = rc;
2761                 fsg_intf_desc.iInterface = rc;
2762         }
2763
2764         /*
2765          * Create the LUNs, open their backing files, and register the
2766          * LUN devices in sysfs.
2767          */
2768         curlun = kzalloc(nluns * sizeof *curlun, GFP_KERNEL);
2769         if (unlikely(!curlun)) {
2770                 rc = -ENOMEM;
2771                 goto error_release;
2772         }
2773         common->luns = curlun;
2774
2775         init_rwsem(&common->filesem);
2776
2777         for (i = 0, lcfg = cfg->luns; i < nluns; ++i, ++curlun, ++lcfg) {
2778                 curlun->cdrom = !!lcfg->cdrom;
2779                 curlun->ro = lcfg->cdrom || lcfg->ro;
2780                 curlun->initially_ro = curlun->ro;
2781                 curlun->removable = lcfg->removable;
2782                 curlun->dev.release = fsg_lun_release;
2783                 curlun->dev.parent = &gadget->dev;
2784                 /* curlun->dev.driver = &fsg_driver.driver; XXX */
2785                 dev_set_drvdata(&curlun->dev, &common->filesem);
2786                 dev_set_name(&curlun->dev,
2787                              cfg->lun_name_format
2788                            ? cfg->lun_name_format
2789                            : "lun%d",
2790                              i);
2791
2792                 rc = device_register(&curlun->dev);
2793                 if (rc) {
2794                         INFO(common, "failed to register LUN%d: %d\n", i, rc);
2795                         common->nluns = i;
2796                         put_device(&curlun->dev);
2797                         goto error_release;
2798                 }
2799
2800                 rc = device_create_file(&curlun->dev, &dev_attr_ro);
2801                 if (rc)
2802                         goto error_luns;
2803                 rc = device_create_file(&curlun->dev, &dev_attr_file);
2804                 if (rc)
2805                         goto error_luns;
2806                 rc = device_create_file(&curlun->dev, &dev_attr_nofua);
2807                 if (rc)
2808                         goto error_luns;
2809
2810                 if (lcfg->filename) {
2811                         rc = fsg_lun_open(curlun, lcfg->filename);
2812                         if (rc)
2813                                 goto error_luns;
2814                 } else if (!curlun->removable) {
2815                         ERROR(common, "no file given for LUN%d\n", i);
2816                         rc = -EINVAL;
2817                         goto error_luns;
2818                 }
2819         }
2820         common->nluns = nluns;
2821
2822         /* Data buffers cyclic list */
2823         bh = common->buffhds;
2824         i = fsg_num_buffers;
2825         goto buffhds_first_it;
2826         do {
2827                 bh->next = bh + 1;
2828                 ++bh;
2829 buffhds_first_it:
2830                 bh->buf = kmalloc(FSG_BUFLEN, GFP_KERNEL);
2831                 if (unlikely(!bh->buf)) {
2832                         rc = -ENOMEM;
2833                         goto error_release;
2834                 }
2835         } while (--i);
2836         bh->next = common->buffhds;
2837
2838         /* Prepare inquiryString */
2839         if (cfg->release != 0xffff) {
2840                 i = cfg->release;
2841         } else {
2842                 i = usb_gadget_controller_number(gadget);
2843                 if (i >= 0) {
2844                         i = 0x0300 + i;
2845                 } else {
2846                         WARNING(common, "controller '%s' not recognized\n",
2847                                 gadget->name);
2848                         i = 0x0399;
2849                 }
2850         }
2851         snprintf(common->inquiry_string, sizeof common->inquiry_string,
2852                  "%-8s%-16s%04x", cfg->vendor_name ?: "Linux",
2853                  /* Assume product name dependent on the first LUN */
2854                  cfg->product_name ?: (common->luns->cdrom
2855                                      ? "File-Stor Gadget"
2856                                      : "File-CD Gadget"),
2857                  i);
2858
2859         /*
2860          * Some peripheral controllers are known not to be able to
2861          * halt bulk endpoints correctly.  If one of them is present,
2862          * disable stalls.
2863          */
2864         common->can_stall = cfg->can_stall &&
2865                 !(gadget_is_at91(common->gadget));
2866
2867         spin_lock_init(&common->lock);
2868         kref_init(&common->ref);
2869
2870         /* Tell the thread to start working */
2871         common->thread_task =
2872                 kthread_create(fsg_main_thread, common,
2873                                cfg->thread_name ?: "file-storage");
2874         if (IS_ERR(common->thread_task)) {
2875                 rc = PTR_ERR(common->thread_task);
2876                 goto error_release;
2877         }
2878         init_completion(&common->thread_notifier);
2879