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  * SPDX-License-Identifier: GPL-2.0+	BSD-3-Clause
10  */
11 
12 /*
13  * The Mass Storage Function acts as a USB Mass Storage device,
14  * appearing to the host as a disk drive or as a CD-ROM drive.  In
15  * addition to providing an example of a genuinely useful composite
16  * function for a USB device, it also illustrates a technique of
17  * double-buffering for increased throughput.
18  *
19  * Function supports multiple logical units (LUNs).  Backing storage
20  * for each LUN is provided by a regular file or a block device.
21  * Access for each LUN can be limited to read-only.  Moreover, the
22  * function can indicate that LUN is removable and/or CD-ROM.  (The
23  * later implies read-only access.)
24  *
25  * MSF is configured by specifying a fsg_config structure.  It has the
26  * following fields:
27  *
28  *	nluns		Number of LUNs function have (anywhere from 1
29  *				to FSG_MAX_LUNS which is 8).
30  *	luns		An array of LUN configuration values.  This
31  *				should be filled for each LUN that
32  *				function will include (ie. for "nluns"
33  *				LUNs).  Each element of the array has
34  *				the following fields:
35  *	->filename	The path to the backing file for the LUN.
36  *				Required if LUN is not marked as
37  *				removable.
38  *	->ro		Flag specifying access to the LUN shall be
39  *				read-only.  This is implied if CD-ROM
40  *				emulation is enabled as well as when
41  *				it was impossible to open "filename"
42  *				in R/W mode.
43  *	->removable	Flag specifying that LUN shall be indicated as
44  *				being removable.
45  *	->cdrom		Flag specifying that LUN shall be reported as
46  *				being a CD-ROM.
47  *
48  *	lun_name_format	A printf-like format for names of the LUN
49  *				devices.  This determines how the
50  *				directory in sysfs will be named.
51  *				Unless you are using several MSFs in
52  *				a single gadget (as opposed to single
53  *				MSF in many configurations) you may
54  *				leave it as NULL (in which case
55  *				"lun%d" will be used).  In the format
56  *				you can use "%d" to index LUNs for
57  *				MSF's with more than one LUN.  (Beware
58  *				that there is only one integer given
59  *				as an argument for the format and
60  *				specifying invalid format may cause
61  *				unspecified behaviour.)
62  *	thread_name	Name of the kernel thread process used by the
63  *				MSF.  You can safely set it to NULL
64  *				(in which case default "file-storage"
65  *				will be used).
66  *
67  *	vendor_name
68  *	product_name
69  *	release		Information used as a reply to INQUIRY
70  *				request.  To use default set to NULL,
71  *				NULL, 0xffff respectively.  The first
72  *				field should be 8 and the second 16
73  *				characters or less.
74  *
75  *	can_stall	Set to permit function to halt bulk endpoints.
76  *				Disabled on some USB devices known not
77  *				to work correctly.  You should set it
78  *				to true.
79  *
80  * If "removable" is not set for a LUN then a backing file must be
81  * specified.  If it is set, then NULL filename means the LUN's medium
82  * is not loaded (an empty string as "filename" in the fsg_config
83  * structure causes error).  The CD-ROM emulation includes a single
84  * data track and no audio tracks; hence there need be only one
85  * backing file per LUN.  Note also that the CD-ROM block length is
86  * set to 512 rather than the more common value 2048.
87  *
88  *
89  * MSF includes support for module parameters.  If gadget using it
90  * decides to use it, the following module parameters will be
91  * available:
92  *
93  *	file=filename[,filename...]
94  *			Names of the files or block devices used for
95  *				backing storage.
96  *	ro=b[,b...]	Default false, boolean for read-only access.
97  *	removable=b[,b...]
98  *			Default true, boolean for removable media.
99  *	cdrom=b[,b...]	Default false, boolean for whether to emulate
100  *				a CD-ROM drive.
101  *	luns=N		Default N = number of filenames, number of
102  *				LUNs to support.
103  *	stall		Default determined according to the type of
104  *				USB device controller (usually true),
105  *				boolean to permit the driver to halt
106  *				bulk endpoints.
107  *
108  * The module parameters may be prefixed with some string.  You need
109  * to consult gadget's documentation or source to verify whether it is
110  * using those module parameters and if it does what are the prefixes
111  * (look for FSG_MODULE_PARAMETERS() macro usage, what's inside it is
112  * the prefix).
113  *
114  *
115  * Requirements are modest; only a bulk-in and a bulk-out endpoint are
116  * needed.  The memory requirement amounts to two 16K buffers, size
117  * configurable by a parameter.  Support is included for both
118  * full-speed and high-speed operation.
119  *
120  * Note that the driver is slightly non-portable in that it assumes a
121  * single memory/DMA buffer will be useable for bulk-in, bulk-out, and
122  * interrupt-in endpoints.  With most device controllers this isn't an
123  * issue, but there may be some with hardware restrictions that prevent
124  * a buffer from being used by more than one endpoint.
125  *
126  *
127  * The pathnames of the backing files and the ro settings are
128  * available in the attribute files "file" and "ro" in the lun<n> (or
129  * to be more precise in a directory which name comes from
130  * "lun_name_format" option!) subdirectory of the gadget's sysfs
131  * directory.  If the "removable" option is set, writing to these
132  * files will simulate ejecting/loading the medium (writing an empty
133  * line means eject) and adjusting a write-enable tab.  Changes to the
134  * ro setting are not allowed when the medium is loaded or if CD-ROM
135  * emulation is being used.
136  *
137  * When a LUN receive an "eject" SCSI request (Start/Stop Unit),
138  * if the LUN is removable, the backing file is released to simulate
139  * ejection.
140  *
141  *
142  * This function is heavily based on "File-backed Storage Gadget" by
143  * Alan Stern which in turn is heavily based on "Gadget Zero" by David
144  * Brownell.  The driver's SCSI command interface was based on the
145  * "Information technology - Small Computer System Interface - 2"
146  * document from X3T9.2 Project 375D, Revision 10L, 7-SEP-93,
147  * available at <http://www.t10.org/ftp/t10/drafts/s2/s2-r10l.pdf>.
148  * The single exception is opcode 0x23 (READ FORMAT CAPACITIES), which
149  * was based on the "Universal Serial Bus Mass Storage Class UFI
150  * Command Specification" document, Revision 1.0, December 14, 1998,
151  * available at
152  * <http://www.usb.org/developers/devclass_docs/usbmass-ufi10.pdf>.
153  */
154 
155 /*
156  *				Driver Design
157  *
158  * The MSF is fairly straightforward.  There is a main kernel
159  * thread that handles most of the work.  Interrupt routines field
160  * callbacks from the controller driver: bulk- and interrupt-request
161  * completion notifications, endpoint-0 events, and disconnect events.
162  * Completion events are passed to the main thread by wakeup calls.  Many
163  * ep0 requests are handled at interrupt time, but SetInterface,
164  * SetConfiguration, and device reset requests are forwarded to the
165  * thread in the form of "exceptions" using SIGUSR1 signals (since they
166  * should interrupt any ongoing file I/O operations).
167  *
168  * The thread's main routine implements the standard command/data/status
169  * parts of a SCSI interaction.  It and its subroutines are full of tests
170  * for pending signals/exceptions -- all this polling is necessary since
171  * the kernel has no setjmp/longjmp equivalents.  (Maybe this is an
172  * indication that the driver really wants to be running in userspace.)
173  * An important point is that so long as the thread is alive it keeps an
174  * open reference to the backing file.  This will prevent unmounting
175  * the backing file's underlying filesystem and could cause problems
176  * during system shutdown, for example.  To prevent such problems, the
177  * thread catches INT, TERM, and KILL signals and converts them into
178  * an EXIT exception.
179  *
180  * In normal operation the main thread is started during the gadget's
181  * fsg_bind() callback and stopped during fsg_unbind().  But it can
182  * also exit when it receives a signal, and there's no point leaving
183  * the gadget running when the thread is dead.  At of this moment, MSF
184  * provides no way to deregister the gadget when thread dies -- maybe
185  * a callback functions is needed.
186  *
187  * To provide maximum throughput, the driver uses a circular pipeline of
188  * buffer heads (struct fsg_buffhd).  In principle the pipeline can be
189  * arbitrarily long; in practice the benefits don't justify having more
190  * than 2 stages (i.e., double buffering).  But it helps to think of the
191  * pipeline as being a long one.  Each buffer head contains a bulk-in and
192  * a bulk-out request pointer (since the buffer can be used for both
193  * output and input -- directions always are given from the host's
194  * point of view) as well as a pointer to the buffer and various state
195  * variables.
196  *
197  * Use of the pipeline follows a simple protocol.  There is a variable
198  * (fsg->next_buffhd_to_fill) that points to the next buffer head to use.
199  * At any time that buffer head may still be in use from an earlier
200  * request, so each buffer head has a state variable indicating whether
201  * it is EMPTY, FULL, or BUSY.  Typical use involves waiting for the
202  * buffer head to be EMPTY, filling the buffer either by file I/O or by
203  * USB I/O (during which the buffer head is BUSY), and marking the buffer
204  * head FULL when the I/O is complete.  Then the buffer will be emptied
205  * (again possibly by USB I/O, during which it is marked BUSY) and
206  * finally marked EMPTY again (possibly by a completion routine).
207  *
208  * A module parameter tells the driver to avoid stalling the bulk
209  * endpoints wherever the transport specification allows.  This is
210  * necessary for some UDCs like the SuperH, which cannot reliably clear a
211  * halt on a bulk endpoint.  However, under certain circumstances the
212  * Bulk-only specification requires a stall.  In such cases the driver
213  * will halt the endpoint and set a flag indicating that it should clear
214  * the halt in software during the next device reset.  Hopefully this
215  * will permit everything to work correctly.  Furthermore, although the
216  * specification allows the bulk-out endpoint to halt when the host sends
217  * too much data, implementing this would cause an unavoidable race.
218  * The driver will always use the "no-stall" approach for OUT transfers.
219  *
220  * One subtle point concerns sending status-stage responses for ep0
221  * requests.  Some of these requests, such as device reset, can involve
222  * interrupting an ongoing file I/O operation, which might take an
223  * arbitrarily long time.  During that delay the host might give up on
224  * the original ep0 request and issue a new one.  When that happens the
225  * driver should not notify the host about completion of the original
226  * request, as the host will no longer be waiting for it.  So the driver
227  * assigns to each ep0 request a unique tag, and it keeps track of the
228  * tag value of the request associated with a long-running exception
229  * (device-reset, interface-change, or configuration-change).  When the
230  * exception handler is finished, the status-stage response is submitted
231  * only if the current ep0 request tag is equal to the exception request
232  * tag.  Thus only the most recently received ep0 request will get a
233  * status-stage response.
234  *
235  * Warning: This driver source file is too long.  It ought to be split up
236  * into a header file plus about 3 separate .c files, to handle the details
237  * of the Gadget, USB Mass Storage, and SCSI protocols.
238  */
239 
240 /* #define VERBOSE_DEBUG */
241 /* #define DUMP_MSGS */
242 
243 #include <config.h>
244 #include <malloc.h>
245 #include <common.h>
246 #include <g_dnl.h>
247 
248 #include <linux/err.h>
249 #include <linux/usb/ch9.h>
250 #include <linux/usb/gadget.h>
251 #include <usb_mass_storage.h>
252 
253 #include <asm/unaligned.h>
254 #include <linux/usb/gadget.h>
255 #include <linux/usb/gadget.h>
256 #include <linux/usb/composite.h>
257 #include <usb/lin_gadget_compat.h>
258 #include <g_dnl.h>
259 
260 /*------------------------------------------------------------------------*/
261 
262 #define FSG_DRIVER_DESC	"Mass Storage Function"
263 #define FSG_DRIVER_VERSION	"2012/06/5"
264 
265 static const char fsg_string_interface[] = "Mass Storage";
266 
267 #define FSG_NO_INTR_EP 1
268 #define FSG_NO_DEVICE_STRINGS    1
269 #define FSG_NO_OTG               1
270 #define FSG_NO_INTR_EP           1
271 
272 #include "storage_common.c"
273 
274 /*-------------------------------------------------------------------------*/
275 
276 #define GFP_ATOMIC ((gfp_t) 0)
277 #define PAGE_CACHE_SHIFT	12
278 #define PAGE_CACHE_SIZE		(1 << PAGE_CACHE_SHIFT)
279 #define kthread_create(...)	__builtin_return_address(0)
280 #define wait_for_completion(...) do {} while (0)
281 
282 struct kref {int x; };
283 struct completion {int x; };
284 
285 inline void set_bit(int nr, volatile void *addr)
286 {
287 	int	mask;
288 	unsigned int *a = (unsigned int *) addr;
289 
290 	a += nr >> 5;
291 	mask = 1 << (nr & 0x1f);
292 	*a |= mask;
293 }
294 
295 inline void clear_bit(int nr, volatile void *addr)
296 {
297 	int	mask;
298 	unsigned int *a = (unsigned int *) addr;
299 
300 	a += nr >> 5;
301 	mask = 1 << (nr & 0x1f);
302 	*a &= ~mask;
303 }
304 
305 struct fsg_dev;
306 struct fsg_common;
307 
308 /* Data shared by all the FSG instances. */
309 struct fsg_common {
310 	struct usb_gadget	*gadget;
311 	struct fsg_dev		*fsg, *new_fsg;
312 
313 	struct usb_ep		*ep0;		/* Copy of gadget->ep0 */
314 	struct usb_request	*ep0req;	/* Copy of cdev->req */
315 	unsigned int		ep0_req_tag;
316 
317 	struct fsg_buffhd	*next_buffhd_to_fill;
318 	struct fsg_buffhd	*next_buffhd_to_drain;
319 	struct fsg_buffhd	buffhds[FSG_NUM_BUFFERS];
320 
321 	int			cmnd_size;
322 	u8			cmnd[MAX_COMMAND_SIZE];
323 
324 	unsigned int		nluns;
325 	unsigned int		lun;
326 	struct fsg_lun          luns[FSG_MAX_LUNS];
327 
328 	unsigned int		bulk_out_maxpacket;
329 	enum fsg_state		state;		/* For exception handling */
330 	unsigned int		exception_req_tag;
331 
332 	enum data_direction	data_dir;
333 	u32			data_size;
334 	u32			data_size_from_cmnd;
335 	u32			tag;
336 	u32			residue;
337 	u32			usb_amount_left;
338 
339 	unsigned int		can_stall:1;
340 	unsigned int		free_storage_on_release:1;
341 	unsigned int		phase_error:1;
342 	unsigned int		short_packet_received:1;
343 	unsigned int		bad_lun_okay:1;
344 	unsigned int		running:1;
345 
346 	int			thread_wakeup_needed;
347 	struct completion	thread_notifier;
348 	struct task_struct	*thread_task;
349 
350 	/* Callback functions. */
351 	const struct fsg_operations	*ops;
352 	/* Gadget's private data. */
353 	void			*private_data;
354 
355 	const char *vendor_name;		/*  8 characters or less */
356 	const char *product_name;		/* 16 characters or less */
357 	u16 release;
358 
359 	/* Vendor (8 chars), product (16 chars), release (4
360 	 * hexadecimal digits) and NUL byte */
361 	char inquiry_string[8 + 16 + 4 + 1];
362 
363 	struct kref		ref;
364 };
365 
366 struct fsg_config {
367 	unsigned nluns;
368 	struct fsg_lun_config {
369 		const char *filename;
370 		char ro;
371 		char removable;
372 		char cdrom;
373 		char nofua;
374 	} luns[FSG_MAX_LUNS];
375 
376 	/* Callback functions. */
377 	const struct fsg_operations     *ops;
378 	/* Gadget's private data. */
379 	void			*private_data;
380 
381 	const char *vendor_name;		/*  8 characters or less */
382 	const char *product_name;		/* 16 characters or less */
383 
384 	char			can_stall;
385 };
386 
387 struct fsg_dev {
388 	struct usb_function	function;
389 	struct usb_gadget	*gadget;	/* Copy of cdev->gadget */
390 	struct fsg_common	*common;
391 
392 	u16			interface_number;
393 
394 	unsigned int		bulk_in_enabled:1;
395 	unsigned int		bulk_out_enabled:1;
396 
397 	unsigned long		atomic_bitflags;
398 #define IGNORE_BULK_OUT		0
399 
400 	struct usb_ep		*bulk_in;
401 	struct usb_ep		*bulk_out;
402 };
403 
404 
405 static inline int __fsg_is_set(struct fsg_common *common,
406 			       const char *func, unsigned line)
407 {
408 	if (common->fsg)
409 		return 1;
410 	ERROR(common, "common->fsg is NULL in %s at %u\n", func, line);
411 	WARN_ON(1);
412 	return 0;
413 }
414 
415 #define fsg_is_set(common) likely(__fsg_is_set(common, __func__, __LINE__))
416 
417 
418 static inline struct fsg_dev *fsg_from_func(struct usb_function *f)
419 {
420 	return container_of(f, struct fsg_dev, function);
421 }
422 
423 
424 typedef void (*fsg_routine_t)(struct fsg_dev *);
425 
426 static int exception_in_progress(struct fsg_common *common)
427 {
428 	return common->state > FSG_STATE_IDLE;
429 }
430 
431 /* Make bulk-out requests be divisible by the maxpacket size */
432 static void set_bulk_out_req_length(struct fsg_common *common,
433 		struct fsg_buffhd *bh, unsigned int length)
434 {
435 	unsigned int	rem;
436 
437 	bh->bulk_out_intended_length = length;
438 	rem = length % common->bulk_out_maxpacket;
439 	if (rem > 0)
440 		length += common->bulk_out_maxpacket - rem;
441 	bh->outreq->length = length;
442 }
443 
444 /*-------------------------------------------------------------------------*/
445 
446 struct ums *ums;
447 struct fsg_common *the_fsg_common;
448 
449 static int fsg_set_halt(struct fsg_dev *fsg, struct usb_ep *ep)
450 {
451 	const char	*name;
452 
453 	if (ep == fsg->bulk_in)
454 		name = "bulk-in";
455 	else if (ep == fsg->bulk_out)
456 		name = "bulk-out";
457 	else
458 		name = ep->name;
459 	DBG(fsg, "%s set halt\n", name);
460 	return usb_ep_set_halt(ep);
461 }
462 
463 /*-------------------------------------------------------------------------*/
464 
465 /* These routines may be called in process context or in_irq */
466 
467 /* Caller must hold fsg->lock */
468 static void wakeup_thread(struct fsg_common *common)
469 {
470 	common->thread_wakeup_needed = 1;
471 }
472 
473 static void raise_exception(struct fsg_common *common, enum fsg_state new_state)
474 {
475 	/* Do nothing if a higher-priority exception is already in progress.
476 	 * If a lower-or-equal priority exception is in progress, preempt it
477 	 * and notify the main thread by sending it a signal. */
478 	if (common->state <= new_state) {
479 		common->exception_req_tag = common->ep0_req_tag;
480 		common->state = new_state;
481 		common->thread_wakeup_needed = 1;
482 	}
483 }
484 
485 /*-------------------------------------------------------------------------*/
486 
487 static int ep0_queue(struct fsg_common *common)
488 {
489 	int	rc;
490 
491 	rc = usb_ep_queue(common->ep0, common->ep0req, GFP_ATOMIC);
492 	common->ep0->driver_data = common;
493 	if (rc != 0 && rc != -ESHUTDOWN) {
494 		/* We can't do much more than wait for a reset */
495 		WARNING(common, "error in submission: %s --> %d\n",
496 			common->ep0->name, rc);
497 	}
498 	return rc;
499 }
500 
501 /*-------------------------------------------------------------------------*/
502 
503 /* Bulk and interrupt endpoint completion handlers.
504  * These always run in_irq. */
505 
506 static void bulk_in_complete(struct usb_ep *ep, struct usb_request *req)
507 {
508 	struct fsg_common	*common = ep->driver_data;
509 	struct fsg_buffhd	*bh = req->context;
510 
511 	if (req->status || req->actual != req->length)
512 		DBG(common, "%s --> %d, %u/%u\n", __func__,
513 				req->status, req->actual, req->length);
514 	if (req->status == -ECONNRESET)		/* Request was cancelled */
515 		usb_ep_fifo_flush(ep);
516 
517 	/* Hold the lock while we update the request and buffer states */
518 	bh->inreq_busy = 0;
519 	bh->state = BUF_STATE_EMPTY;
520 	wakeup_thread(common);
521 }
522 
523 static void bulk_out_complete(struct usb_ep *ep, struct usb_request *req)
524 {
525 	struct fsg_common	*common = ep->driver_data;
526 	struct fsg_buffhd	*bh = req->context;
527 
528 	dump_msg(common, "bulk-out", req->buf, req->actual);
529 	if (req->status || req->actual != bh->bulk_out_intended_length)
530 		DBG(common, "%s --> %d, %u/%u\n", __func__,
531 				req->status, req->actual,
532 				bh->bulk_out_intended_length);
533 	if (req->status == -ECONNRESET)		/* Request was cancelled */
534 		usb_ep_fifo_flush(ep);
535 
536 	/* Hold the lock while we update the request and buffer states */
537 	bh->outreq_busy = 0;
538 	bh->state = BUF_STATE_FULL;
539 	wakeup_thread(common);
540 }
541 
542 /*-------------------------------------------------------------------------*/
543 
544 /* Ep0 class-specific handlers.  These always run in_irq. */
545 
546 static int fsg_setup(struct usb_function *f,
547 		const struct usb_ctrlrequest *ctrl)
548 {
549 	struct fsg_dev		*fsg = fsg_from_func(f);
550 	struct usb_request	*req = fsg->common->ep0req;
551 	u16			w_index = get_unaligned_le16(&ctrl->wIndex);
552 	u16			w_value = get_unaligned_le16(&ctrl->wValue);
553 	u16			w_length = get_unaligned_le16(&ctrl->wLength);
554 
555 	if (!fsg_is_set(fsg->common))
556 		return -EOPNOTSUPP;
557 
558 	switch (ctrl->bRequest) {
559 
560 	case USB_BULK_RESET_REQUEST:
561 		if (ctrl->bRequestType !=
562 		    (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE))
563 			break;
564 		if (w_index != fsg->interface_number || w_value != 0)
565 			return -EDOM;
566 
567 		/* Raise an exception to stop the current operation
568 		 * and reinitialize our state. */
569 		DBG(fsg, "bulk reset request\n");
570 		raise_exception(fsg->common, FSG_STATE_RESET);
571 		return DELAYED_STATUS;
572 
573 	case USB_BULK_GET_MAX_LUN_REQUEST:
574 		if (ctrl->bRequestType !=
575 		    (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE))
576 			break;
577 		if (w_index != fsg->interface_number || w_value != 0)
578 			return -EDOM;
579 		VDBG(fsg, "get max LUN\n");
580 		*(u8 *) req->buf = fsg->common->nluns - 1;
581 
582 		/* Respond with data/status */
583 		req->length = min((u16)1, w_length);
584 		return ep0_queue(fsg->common);
585 	}
586 
587 	VDBG(fsg,
588 	     "unknown class-specific control req "
589 	     "%02x.%02x v%04x i%04x l%u\n",
590 	     ctrl->bRequestType, ctrl->bRequest,
591 	     get_unaligned_le16(&ctrl->wValue), w_index, w_length);
592 	return -EOPNOTSUPP;
593 }
594 
595 /*-------------------------------------------------------------------------*/
596 
597 /* All the following routines run in process context */
598 
599 /* Use this for bulk or interrupt transfers, not ep0 */
600 static void start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
601 		struct usb_request *req, int *pbusy,
602 		enum fsg_buffer_state *state)
603 {
604 	int	rc;
605 
606 	if (ep == fsg->bulk_in)
607 		dump_msg(fsg, "bulk-in", req->buf, req->length);
608 
609 	*pbusy = 1;
610 	*state = BUF_STATE_BUSY;
611 	rc = usb_ep_queue(ep, req, GFP_KERNEL);
612 	if (rc != 0) {
613 		*pbusy = 0;
614 		*state = BUF_STATE_EMPTY;
615 
616 		/* We can't do much more than wait for a reset */
617 
618 		/* Note: currently the net2280 driver fails zero-length
619 		 * submissions if DMA is enabled. */
620 		if (rc != -ESHUTDOWN && !(rc == -EOPNOTSUPP &&
621 						req->length == 0))
622 			WARNING(fsg, "error in submission: %s --> %d\n",
623 					ep->name, rc);
624 	}
625 }
626 
627 #define START_TRANSFER_OR(common, ep_name, req, pbusy, state)		\
628 	if (fsg_is_set(common))						\
629 		start_transfer((common)->fsg, (common)->fsg->ep_name,	\
630 			       req, pbusy, state);			\
631 	else
632 
633 #define START_TRANSFER(common, ep_name, req, pbusy, state)		\
634 	START_TRANSFER_OR(common, ep_name, req, pbusy, state) (void)0
635 
636 static void busy_indicator(void)
637 {
638 	static int state;
639 
640 	switch (state) {
641 	case 0:
642 		puts("\r|"); break;
643 	case 1:
644 		puts("\r/"); break;
645 	case 2:
646 		puts("\r-"); break;
647 	case 3:
648 		puts("\r\\"); break;
649 	case 4:
650 		puts("\r|"); break;
651 	case 5:
652 		puts("\r/"); break;
653 	case 6:
654 		puts("\r-"); break;
655 	case 7:
656 		puts("\r\\"); break;
657 	default:
658 		state = 0;
659 	}
660 	if (state++ == 8)
661 		state = 0;
662 }
663 
664 static int sleep_thread(struct fsg_common *common)
665 {
666 	int	rc = 0;
667 	int i = 0, k = 0;
668 
669 	/* Wait until a signal arrives or we are woken up */
670 	for (;;) {
671 		if (common->thread_wakeup_needed)
672 			break;
673 
674 		if (++i == 20000) {
675 			busy_indicator();
676 			i = 0;
677 			k++;
678 		}
679 
680 		if (k == 10) {
681 			/* Handle CTRL+C */
682 			if (ctrlc())
683 				return -EPIPE;
684 
685 			/* Check cable connection */
686 			if (!g_dnl_board_usb_cable_connected())
687 				return -EIO;
688 
689 			k = 0;
690 		}
691 
692 		usb_gadget_handle_interrupts(0);
693 	}
694 	common->thread_wakeup_needed = 0;
695 	return rc;
696 }
697 
698 /*-------------------------------------------------------------------------*/
699 
700 static int do_read(struct fsg_common *common)
701 {
702 	struct fsg_lun		*curlun = &common->luns[common->lun];
703 	u32			lba;
704 	struct fsg_buffhd	*bh;
705 	int			rc;
706 	u32			amount_left;
707 	loff_t			file_offset;
708 	unsigned int		amount;
709 	unsigned int		partial_page;
710 	ssize_t			nread;
711 
712 	/* Get the starting Logical Block Address and check that it's
713 	 * not too big */
714 	if (common->cmnd[0] == SC_READ_6)
715 		lba = get_unaligned_be24(&common->cmnd[1]);
716 	else {
717 		lba = get_unaligned_be32(&common->cmnd[2]);
718 
719 		/* We allow DPO (Disable Page Out = don't save data in the
720 		 * cache) and FUA (Force Unit Access = don't read from the
721 		 * cache), but we don't implement them. */
722 		if ((common->cmnd[1] & ~0x18) != 0) {
723 			curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
724 			return -EINVAL;
725 		}
726 	}
727 	if (lba >= curlun->num_sectors) {
728 		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
729 		return -EINVAL;
730 	}
731 	file_offset = ((loff_t) lba) << 9;
732 
733 	/* Carry out the file reads */
734 	amount_left = common->data_size_from_cmnd;
735 	if (unlikely(amount_left == 0))
736 		return -EIO;		/* No default reply */
737 
738 	for (;;) {
739 
740 		/* Figure out how much we need to read:
741 		 * Try to read the remaining amount.
742 		 * But don't read more than the buffer size.
743 		 * And don't try to read past the end of the file.
744 		 * Finally, if we're not at a page boundary, don't read past
745 		 *	the next page.
746 		 * If this means reading 0 then we were asked to read past
747 		 *	the end of file. */
748 		amount = min(amount_left, FSG_BUFLEN);
749 		partial_page = file_offset & (PAGE_CACHE_SIZE - 1);
750 		if (partial_page > 0)
751 			amount = min(amount, (unsigned int) PAGE_CACHE_SIZE -
752 					partial_page);
753 
754 		/* Wait for the next buffer to become available */
755 		bh = common->next_buffhd_to_fill;
756 		while (bh->state != BUF_STATE_EMPTY) {
757 			rc = sleep_thread(common);
758 			if (rc)
759 				return rc;
760 		}
761 
762 		/* If we were asked to read past the end of file,
763 		 * end with an empty buffer. */
764 		if (amount == 0) {
765 			curlun->sense_data =
766 					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
767 			curlun->info_valid = 1;
768 			bh->inreq->length = 0;
769 			bh->state = BUF_STATE_FULL;
770 			break;
771 		}
772 
773 		/* Perform the read */
774 		rc = ums->read_sector(ums,
775 				      file_offset / SECTOR_SIZE,
776 				      amount / SECTOR_SIZE,
777 				      (char __user *)bh->buf);
778 		if (!rc)
779 			return -EIO;
780 
781 		nread = rc * SECTOR_SIZE;
782 
783 		VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
784 				(unsigned long long) file_offset,
785 				(int) nread);
786 
787 		if (nread < 0) {
788 			LDBG(curlun, "error in file read: %d\n",
789 					(int) nread);
790 			nread = 0;
791 		} else if (nread < amount) {
792 			LDBG(curlun, "partial file read: %d/%u\n",
793 					(int) nread, amount);
794 			nread -= (nread & 511);	/* Round down to a block */
795 		}
796 		file_offset  += nread;
797 		amount_left  -= nread;
798 		common->residue -= nread;
799 		bh->inreq->length = nread;
800 		bh->state = BUF_STATE_FULL;
801 
802 		/* If an error occurred, report it and its position */
803 		if (nread < amount) {
804 			curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
805 			curlun->info_valid = 1;
806 			break;
807 		}
808 
809 		if (amount_left == 0)
810 			break;		/* No more left to read */
811 
812 		/* Send this buffer and go read some more */
813 		bh->inreq->zero = 0;
814 		START_TRANSFER_OR(common, bulk_in, bh->inreq,
815 			       &bh->inreq_busy, &bh->state)
816 			/* Don't know what to do if
817 			 * common->fsg is NULL */
818 			return -EIO;
819 		common->next_buffhd_to_fill = bh->next;
820 	}
821 
822 	return -EIO;		/* No default reply */
823 }
824 
825 /*-------------------------------------------------------------------------*/
826 
827 static int do_write(struct fsg_common *common)
828 {
829 	struct fsg_lun		*curlun = &common->luns[common->lun];
830 	u32			lba;
831 	struct fsg_buffhd	*bh;
832 	int			get_some_more;
833 	u32			amount_left_to_req, amount_left_to_write;
834 	loff_t			usb_offset, file_offset;
835 	unsigned int		amount;
836 	unsigned int		partial_page;
837 	ssize_t			nwritten;
838 	int			rc;
839 
840 	if (curlun->ro) {
841 		curlun->sense_data = SS_WRITE_PROTECTED;
842 		return -EINVAL;
843 	}
844 
845 	/* Get the starting Logical Block Address and check that it's
846 	 * not too big */
847 	if (common->cmnd[0] == SC_WRITE_6)
848 		lba = get_unaligned_be24(&common->cmnd[1]);
849 	else {
850 		lba = get_unaligned_be32(&common->cmnd[2]);
851 
852 		/* We allow DPO (Disable Page Out = don't save data in the
853 		 * cache) and FUA (Force Unit Access = write directly to the
854 		 * medium).  We don't implement DPO; we implement FUA by
855 		 * performing synchronous output. */
856 		if (common->cmnd[1] & ~0x18) {
857 			curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
858 			return -EINVAL;
859 		}
860 	}
861 	if (lba >= curlun->num_sectors) {
862 		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
863 		return -EINVAL;
864 	}
865 
866 	/* Carry out the file writes */
867 	get_some_more = 1;
868 	file_offset = usb_offset = ((loff_t) lba) << 9;
869 	amount_left_to_req = common->data_size_from_cmnd;
870 	amount_left_to_write = common->data_size_from_cmnd;
871 
872 	while (amount_left_to_write > 0) {
873 
874 		/* Queue a request for more data from the host */
875 		bh = common->next_buffhd_to_fill;
876 		if (bh->state == BUF_STATE_EMPTY && get_some_more) {
877 
878 			/* Figure out how much we want to get:
879 			 * Try to get the remaining amount.
880 			 * But don't get more than the buffer size.
881 			 * And don't try to go past the end of the file.
882 			 * If we're not at a page boundary,
883 			 *	don't go past the next page.
884 			 * If this means getting 0, then we were asked
885 			 *	to write past the end of file.
886 			 * Finally, round down to a block boundary. */
887 			amount = min(amount_left_to_req, FSG_BUFLEN);
888 			partial_page = usb_offset & (PAGE_CACHE_SIZE - 1);
889 			if (partial_page > 0)
890 				amount = min(amount,
891 	(unsigned int) PAGE_CACHE_SIZE - partial_page);
892 
893 			if (amount == 0) {
894 				get_some_more = 0;
895 				curlun->sense_data =
896 					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
897 				curlun->info_valid = 1;
898 				continue;
899 			}
900 			amount -= (amount & 511);
901 			if (amount == 0) {
902 
903 				/* Why were we were asked to transfer a
904 				 * partial block? */
905 				get_some_more = 0;
906 				continue;
907 			}
908 
909 			/* Get the next buffer */
910 			usb_offset += amount;
911 			common->usb_amount_left -= amount;
912 			amount_left_to_req -= amount;
913 			if (amount_left_to_req == 0)
914 				get_some_more = 0;
915 
916 			/* amount is always divisible by 512, hence by
917 			 * the bulk-out maxpacket size */
918 			bh->outreq->length = amount;
919 			bh->bulk_out_intended_length = amount;
920 			bh->outreq->short_not_ok = 1;
921 			START_TRANSFER_OR(common, bulk_out, bh->outreq,
922 					  &bh->outreq_busy, &bh->state)
923 				/* Don't know what to do if
924 				 * common->fsg is NULL */
925 				return -EIO;
926 			common->next_buffhd_to_fill = bh->next;
927 			continue;
928 		}
929 
930 		/* Write the received data to the backing file */
931 		bh = common->next_buffhd_to_drain;
932 		if (bh->state == BUF_STATE_EMPTY && !get_some_more)
933 			break;			/* We stopped early */
934 		if (bh->state == BUF_STATE_FULL) {
935 			common->next_buffhd_to_drain = bh->next;
936 			bh->state = BUF_STATE_EMPTY;
937 
938 			/* Did something go wrong with the transfer? */
939 			if (bh->outreq->status != 0) {
940 				curlun->sense_data = SS_COMMUNICATION_FAILURE;
941 				curlun->info_valid = 1;
942 				break;
943 			}
944 
945 			amount = bh->outreq->actual;
946 
947 			/* Perform the write */
948 			rc = ums->write_sector(ums,
949 					       file_offset / SECTOR_SIZE,
950 					       amount / SECTOR_SIZE,
951 					       (char __user *)bh->buf);
952 			if (!rc)
953 				return -EIO;
954 			nwritten = rc * SECTOR_SIZE;
955 
956 			VLDBG(curlun, "file write %u @ %llu -> %d\n", amount,
957 					(unsigned long long) file_offset,
958 					(int) nwritten);
959 
960 			if (nwritten < 0) {
961 				LDBG(curlun, "error in file write: %d\n",
962 						(int) nwritten);
963 				nwritten = 0;
964 			} else if (nwritten < amount) {
965 				LDBG(curlun, "partial file write: %d/%u\n",
966 						(int) nwritten, amount);
967 				nwritten -= (nwritten & 511);
968 				/* Round down to a block */
969 			}
970 			file_offset += nwritten;
971 			amount_left_to_write -= nwritten;
972 			common->residue -= nwritten;
973 
974 			/* If an error occurred, report it and its position */
975 			if (nwritten < amount) {
976 				printf("nwritten:%zd amount:%u\n", nwritten,
977 				       amount);
978 				curlun->sense_data = SS_WRITE_ERROR;
979 				curlun->info_valid = 1;
980 				break;
981 			}
982 
983 			/* Did the host decide to stop early? */
984 			if (bh->outreq->actual != bh->outreq->length) {
985 				common->short_packet_received = 1;
986 				break;
987 			}
988 			continue;
989 		}
990 
991 		/* Wait for something to happen */
992 		rc = sleep_thread(common);
993 		if (rc)
994 			return rc;
995 	}
996 
997 	return -EIO;		/* No default reply */
998 }
999 
1000 /*-------------------------------------------------------------------------*/
1001 
1002 static int do_synchronize_cache(struct fsg_common *common)
1003 {
1004 	return 0;
1005 }
1006 
1007 /*-------------------------------------------------------------------------*/
1008 
1009 static int do_verify(struct fsg_common *common)
1010 {
1011 	struct fsg_lun		*curlun = &common->luns[common->lun];
1012 	u32			lba;
1013 	u32			verification_length;
1014 	struct fsg_buffhd	*bh = common->next_buffhd_to_fill;
1015 	loff_t			file_offset;
1016 	u32			amount_left;
1017 	unsigned int		amount;
1018 	ssize_t			nread;
1019 	int			rc;
1020 
1021 	/* Get the starting Logical Block Address and check that it's
1022 	 * not too big */
1023 	lba = get_unaligned_be32(&common->cmnd[2]);
1024 	if (lba >= curlun->num_sectors) {
1025 		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1026 		return -EINVAL;
1027 	}
1028 
1029 	/* We allow DPO (Disable Page Out = don't save data in the
1030 	 * cache) but we don't implement it. */
1031 	if (common->cmnd[1] & ~0x10) {
1032 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1033 		return -EINVAL;
1034 	}
1035 
1036 	verification_length = get_unaligned_be16(&common->cmnd[7]);
1037 	if (unlikely(verification_length == 0))
1038 		return -EIO;		/* No default reply */
1039 
1040 	/* Prepare to carry out the file verify */
1041 	amount_left = verification_length << 9;
1042 	file_offset = ((loff_t) lba) << 9;
1043 
1044 	/* Write out all the dirty buffers before invalidating them */
1045 
1046 	/* Just try to read the requested blocks */
1047 	while (amount_left > 0) {
1048 
1049 		/* Figure out how much we need to read:
1050 		 * Try to read the remaining amount, but not more than
1051 		 * the buffer size.
1052 		 * And don't try to read past the end of the file.
1053 		 * If this means reading 0 then we were asked to read
1054 		 * past the end of file. */
1055 		amount = min(amount_left, FSG_BUFLEN);
1056 		if (amount == 0) {
1057 			curlun->sense_data =
1058 					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1059 			curlun->info_valid = 1;
1060 			break;
1061 		}
1062 
1063 		/* Perform the read */
1064 		rc = ums->read_sector(ums,
1065 				      file_offset / SECTOR_SIZE,
1066 				      amount / SECTOR_SIZE,
1067 				      (char __user *)bh->buf);
1068 		if (!rc)
1069 			return -EIO;
1070 		nread = rc * SECTOR_SIZE;
1071 
1072 		VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
1073 				(unsigned long long) file_offset,
1074 				(int) nread);
1075 		if (nread < 0) {
1076 			LDBG(curlun, "error in file verify: %d\n",
1077 					(int) nread);
1078 			nread = 0;
1079 		} else if (nread < amount) {
1080 			LDBG(curlun, "partial file verify: %d/%u\n",
1081 					(int) nread, amount);
1082 			nread -= (nread & 511);	/* Round down to a sector */
1083 		}
1084 		if (nread == 0) {
1085 			curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
1086 			curlun->info_valid = 1;
1087 			break;
1088 		}
1089 		file_offset += nread;
1090 		amount_left -= nread;
1091 	}
1092 	return 0;
1093 }
1094 
1095 /*-------------------------------------------------------------------------*/
1096 
1097 static int do_inquiry(struct fsg_common *common, struct fsg_buffhd *bh)
1098 {
1099 	struct fsg_lun *curlun = &common->luns[common->lun];
1100 	static const char vendor_id[] = "Linux   ";
1101 	u8	*buf = (u8 *) bh->buf;
1102 
1103 	if (!curlun) {		/* Unsupported LUNs are okay */
1104 		common->bad_lun_okay = 1;
1105 		memset(buf, 0, 36);
1106 		buf[0] = 0x7f;		/* Unsupported, no device-type */
1107 		buf[4] = 31;		/* Additional length */
1108 		return 36;
1109 	}
1110 
1111 	memset(buf, 0, 8);
1112 	buf[0] = TYPE_DISK;
1113 	buf[1] = curlun->removable ? 0x80 : 0;
1114 	buf[2] = 2;		/* ANSI SCSI level 2 */
1115 	buf[3] = 2;		/* SCSI-2 INQUIRY data format */
1116 	buf[4] = 31;		/* Additional length */
1117 				/* No special options */
1118 	sprintf((char *) (buf + 8), "%-8s%-16s%04x", (char*) vendor_id ,
1119 			ums->name, (u16) 0xffff);
1120 
1121 	return 36;
1122 }
1123 
1124 
1125 static int do_request_sense(struct fsg_common *common, struct fsg_buffhd *bh)
1126 {
1127 	struct fsg_lun	*curlun = &common->luns[common->lun];
1128 	u8		*buf = (u8 *) bh->buf;
1129 	u32		sd, sdinfo;
1130 	int		valid;
1131 
1132 	/*
1133 	 * From the SCSI-2 spec., section 7.9 (Unit attention condition):
1134 	 *
1135 	 * If a REQUEST SENSE command is received from an initiator
1136 	 * with a pending unit attention condition (before the target
1137 	 * generates the contingent allegiance condition), then the
1138 	 * target shall either:
1139 	 *   a) report any pending sense data and preserve the unit
1140 	 *	attention condition on the logical unit, or,
1141 	 *   b) report the unit attention condition, may discard any
1142 	 *	pending sense data, and clear the unit attention
1143 	 *	condition on the logical unit for that initiator.
1144 	 *
1145 	 * FSG normally uses option a); enable this code to use option b).
1146 	 */
1147 #if 0
1148 	if (curlun && curlun->unit_attention_data != SS_NO_SENSE) {
1149 		curlun->sense_data = curlun->unit_attention_data;
1150 		curlun->unit_attention_data = SS_NO_SENSE;
1151 	}
1152 #endif
1153 
1154 	if (!curlun) {		/* Unsupported LUNs are okay */
1155 		common->bad_lun_okay = 1;
1156 		sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
1157 		sdinfo = 0;
1158 		valid = 0;
1159 	} else {
1160 		sd = curlun->sense_data;
1161 		valid = curlun->info_valid << 7;
1162 		curlun->sense_data = SS_NO_SENSE;
1163 		curlun->info_valid = 0;
1164 	}
1165 
1166 	memset(buf, 0, 18);
1167 	buf[0] = valid | 0x70;			/* Valid, current error */
1168 	buf[2] = SK(sd);
1169 	put_unaligned_be32(sdinfo, &buf[3]);	/* Sense information */
1170 	buf[7] = 18 - 8;			/* Additional sense length */
1171 	buf[12] = ASC(sd);
1172 	buf[13] = ASCQ(sd);
1173 	return 18;
1174 }
1175 
1176 static int do_read_capacity(struct fsg_common *common, struct fsg_buffhd *bh)
1177 {
1178 	struct fsg_lun	*curlun = &common->luns[common->lun];
1179 	u32		lba = get_unaligned_be32(&common->cmnd[2]);
1180 	int		pmi = common->cmnd[8];
1181 	u8		*buf = (u8 *) bh->buf;
1182 
1183 	/* Check the PMI and LBA fields */
1184 	if (pmi > 1 || (pmi == 0 && lba != 0)) {
1185 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1186 		return -EINVAL;
1187 	}
1188 
1189 	put_unaligned_be32(curlun->num_sectors - 1, &buf[0]);
1190 						/* Max logical block */
1191 	put_unaligned_be32(512, &buf[4]);	/* Block length */
1192 	return 8;
1193 }
1194 
1195 static int do_read_header(struct fsg_common *common, struct fsg_buffhd *bh)
1196 {
1197 	struct fsg_lun	*curlun = &common->luns[common->lun];
1198 	int		msf = common->cmnd[1] & 0x02;
1199 	u32		lba = get_unaligned_be32(&common->cmnd[2]);
1200 	u8		*buf = (u8 *) bh->buf;
1201 
1202 	if (common->cmnd[1] & ~0x02) {		/* Mask away MSF */
1203 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1204 		return -EINVAL;
1205 	}
1206 	if (lba >= curlun->num_sectors) {
1207 		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1208 		return -EINVAL;
1209 	}
1210 
1211 	memset(buf, 0, 8);
1212 	buf[0] = 0x01;		/* 2048 bytes of user data, rest is EC */
1213 	store_cdrom_address(&buf[4], msf, lba);
1214 	return 8;
1215 }
1216 
1217 
1218 static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
1219 {
1220 	struct fsg_lun	*curlun = &common->luns[common->lun];
1221 	int		msf = common->cmnd[1] & 0x02;
1222 	int		start_track = common->cmnd[6];
1223 	u8		*buf = (u8 *) bh->buf;
1224 
1225 	if ((common->cmnd[1] & ~0x02) != 0 ||	/* Mask away MSF */
1226 			start_track > 1) {
1227 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1228 		return -EINVAL;
1229 	}
1230 
1231 	memset(buf, 0, 20);
1232 	buf[1] = (20-2);		/* TOC data length */
1233 	buf[2] = 1;			/* First track number */
1234 	buf[3] = 1;			/* Last track number */
1235 	buf[5] = 0x16;			/* Data track, copying allowed */
1236 	buf[6] = 0x01;			/* Only track is number 1 */
1237 	store_cdrom_address(&buf[8], msf, 0);
1238 
1239 	buf[13] = 0x16;			/* Lead-out track is data */
1240 	buf[14] = 0xAA;			/* Lead-out track number */
1241 	store_cdrom_address(&buf[16], msf, curlun->num_sectors);
1242 
1243 	return 20;
1244 }
1245 
1246 static int do_mode_sense(struct fsg_common *common, struct fsg_buffhd *bh)
1247 {
1248 	struct fsg_lun	*curlun = &common->luns[common->lun];
1249 	int		mscmnd = common->cmnd[0];
1250 	u8		*buf = (u8 *) bh->buf;
1251 	u8		*buf0 = buf;
1252 	int		pc, page_code;
1253 	int		changeable_values, all_pages;
1254 	int		valid_page = 0;
1255 	int		len, limit;
1256 
1257 	if ((common->cmnd[1] & ~0x08) != 0) {	/* Mask away DBD */
1258 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1259 		return -EINVAL;
1260 	}
1261 	pc = common->cmnd[2] >> 6;
1262 	page_code = common->cmnd[2] & 0x3f;
1263 	if (pc == 3) {
1264 		curlun->sense_data = SS_SAVING_PARAMETERS_NOT_SUPPORTED;
1265 		return -EINVAL;
1266 	}
1267 	changeable_values = (pc == 1);
1268 	all_pages = (page_code == 0x3f);
1269 
1270 	/* Write the mode parameter header.  Fixed values are: default
1271 	 * medium type, no cache control (DPOFUA), and no block descriptors.
1272 	 * The only variable value is the WriteProtect bit.  We will fill in
1273 	 * the mode data length later. */
1274 	memset(buf, 0, 8);
1275 	if (mscmnd == SC_MODE_SENSE_6) {
1276 		buf[2] = (curlun->ro ? 0x80 : 0x00);		/* WP, DPOFUA */
1277 		buf += 4;
1278 		limit = 255;
1279 	} else {			/* SC_MODE_SENSE_10 */
1280 		buf[3] = (curlun->ro ? 0x80 : 0x00);		/* WP, DPOFUA */
1281 		buf += 8;
1282 		limit = 65535;		/* Should really be FSG_BUFLEN */
1283 	}
1284 
1285 	/* No block descriptors */
1286 
1287 	/* The mode pages, in numerical order.  The only page we support
1288 	 * is the Caching page. */
1289 	if (page_code == 0x08 || all_pages) {
1290 		valid_page = 1;
1291 		buf[0] = 0x08;		/* Page code */
1292 		buf[1] = 10;		/* Page length */
1293 		memset(buf+2, 0, 10);	/* None of the fields are changeable */
1294 
1295 		if (!changeable_values) {
1296 			buf[2] = 0x04;	/* Write cache enable, */
1297 					/* Read cache not disabled */
1298 					/* No cache retention priorities */
1299 			put_unaligned_be16(0xffff, &buf[4]);
1300 					/* Don't disable prefetch */
1301 					/* Minimum prefetch = 0 */
1302 			put_unaligned_be16(0xffff, &buf[8]);
1303 					/* Maximum prefetch */
1304 			put_unaligned_be16(0xffff, &buf[10]);
1305 					/* Maximum prefetch ceiling */
1306 		}
1307 		buf += 12;
1308 	}
1309 
1310 	/* Check that a valid page was requested and the mode data length
1311 	 * isn't too long. */
1312 	len = buf - buf0;
1313 	if (!valid_page || len > limit) {
1314 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1315 		return -EINVAL;
1316 	}
1317 
1318 	/*  Store the mode data length */
1319 	if (mscmnd == SC_MODE_SENSE_6)
1320 		buf0[0] = len - 1;
1321 	else
1322 		put_unaligned_be16(len - 2, buf0);
1323 	return len;
1324 }
1325 
1326 
1327 static int do_start_stop(struct fsg_common *common)
1328 {
1329 	struct fsg_lun	*curlun = &common->luns[common->lun];
1330 
1331 	if (!curlun) {
1332 		return -EINVAL;
1333 	} else if (!curlun->removable) {
1334 		curlun->sense_data = SS_INVALID_COMMAND;
1335 		return -EINVAL;
1336 	}
1337 
1338 	return 0;
1339 }
1340 
1341 static int do_prevent_allow(struct fsg_common *common)
1342 {
1343 	struct fsg_lun	*curlun = &common->luns[common->lun];
1344 	int		prevent;
1345 
1346 	if (!curlun->removable) {
1347 		curlun->sense_data = SS_INVALID_COMMAND;
1348 		return -EINVAL;
1349 	}
1350 
1351 	prevent = common->cmnd[4] & 0x01;
1352 	if ((common->cmnd[4] & ~0x01) != 0) {	/* Mask away Prevent */
1353 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1354 		return -EINVAL;
1355 	}
1356 
1357 	if (curlun->prevent_medium_removal && !prevent)
1358 		fsg_lun_fsync_sub(curlun);
1359 	curlun->prevent_medium_removal = prevent;
1360 	return 0;
1361 }
1362 
1363 
1364 static int do_read_format_capacities(struct fsg_common *common,
1365 			struct fsg_buffhd *bh)
1366 {
1367 	struct fsg_lun	*curlun = &common->luns[common->lun];
1368 	u8		*buf = (u8 *) bh->buf;
1369 
1370 	buf[0] = buf[1] = buf[2] = 0;
1371 	buf[3] = 8;	/* Only the Current/Maximum Capacity Descriptor */
1372 	buf += 4;
1373 
1374 	put_unaligned_be32(curlun->num_sectors, &buf[0]);
1375 						/* Number of blocks */
1376 	put_unaligned_be32(512, &buf[4]);	/* Block length */
1377 	buf[4] = 0x02;				/* Current capacity */
1378 	return 12;
1379 }
1380 
1381 
1382 static int do_mode_select(struct fsg_common *common, struct fsg_buffhd *bh)
1383 {
1384 	struct fsg_lun	*curlun = &common->luns[common->lun];
1385 
1386 	/* We don't support MODE SELECT */
1387 	if (curlun)
1388 		curlun->sense_data = SS_INVALID_COMMAND;
1389 	return -EINVAL;
1390 }
1391 
1392 
1393 /*-------------------------------------------------------------------------*/
1394 
1395 static int halt_bulk_in_endpoint(struct fsg_dev *fsg)
1396 {
1397 	int	rc;
1398 
1399 	rc = fsg_set_halt(fsg, fsg->bulk_in);
1400 	if (rc == -EAGAIN)
1401 		VDBG(fsg, "delayed bulk-in endpoint halt\n");
1402 	while (rc != 0) {
1403 		if (rc != -EAGAIN) {
1404 			WARNING(fsg, "usb_ep_set_halt -> %d\n", rc);
1405 			rc = 0;
1406 			break;
1407 		}
1408 
1409 		rc = usb_ep_set_halt(fsg->bulk_in);
1410 	}
1411 	return rc;
1412 }
1413 
1414 static int wedge_bulk_in_endpoint(struct fsg_dev *fsg)
1415 {
1416 	int	rc;
1417 
1418 	DBG(fsg, "bulk-in set wedge\n");
1419 	rc = 0; /* usb_ep_set_wedge(fsg->bulk_in); */
1420 	if (rc == -EAGAIN)
1421 		VDBG(fsg, "delayed bulk-in endpoint wedge\n");
1422 	while (rc != 0) {
1423 		if (rc != -EAGAIN) {
1424 			WARNING(fsg, "usb_ep_set_wedge -> %d\n", rc);
1425 			rc = 0;
1426 			break;
1427 		}
1428 	}
1429 	return rc;
1430 }
1431 
1432 static int pad_with_zeros(struct fsg_dev *fsg)
1433 {
1434 	struct fsg_buffhd	*bh = fsg->common->next_buffhd_to_fill;
1435 	u32			nkeep = bh->inreq->length;
1436 	u32			nsend;
1437 	int			rc;
1438 
1439 	bh->state = BUF_STATE_EMPTY;		/* For the first iteration */
1440 	fsg->common->usb_amount_left = nkeep + fsg->common->residue;
1441 	while (fsg->common->usb_amount_left > 0) {
1442 
1443 		/* Wait for the next buffer to be free */
1444 		while (bh->state != BUF_STATE_EMPTY) {
1445 			rc = sleep_thread(fsg->common);
1446 			if (rc)
1447 				return rc;
1448 		}
1449 
1450 		nsend = min(fsg->common->usb_amount_left, FSG_BUFLEN);
1451 		memset(bh->buf + nkeep, 0, nsend - nkeep);
1452 		bh->inreq->length = nsend;
1453 		bh->inreq->zero = 0;
1454 		start_transfer(fsg, fsg->bulk_in, bh->inreq,
1455 				&bh->inreq_busy, &bh->state);
1456 		bh = fsg->common->next_buffhd_to_fill = bh->next;
1457 		fsg->common->usb_amount_left -= nsend;
1458 		nkeep = 0;
1459 	}
1460 	return 0;
1461 }
1462 
1463 static int throw_away_data(struct fsg_common *common)
1464 {
1465 	struct fsg_buffhd	*bh;
1466 	u32			amount;
1467 	int			rc;
1468 
1469 	for (bh = common->next_buffhd_to_drain;
1470 	     bh->state != BUF_STATE_EMPTY || common->usb_amount_left > 0;
1471 	     bh = common->next_buffhd_to_drain) {
1472 
1473 		/* Throw away the data in a filled buffer */
1474 		if (bh->state == BUF_STATE_FULL) {
1475 			bh->state = BUF_STATE_EMPTY;
1476 			common->next_buffhd_to_drain = bh->next;
1477 
1478 			/* A short packet or an error ends everything */
1479 			if (bh->outreq->actual != bh->outreq->length ||
1480 					bh->outreq->status != 0) {
1481 				raise_exception(common,
1482 						FSG_STATE_ABORT_BULK_OUT);
1483 				return -EINTR;
1484 			}
1485 			continue;
1486 		}
1487 
1488 		/* Try to submit another request if we need one */
1489 		bh = common->next_buffhd_to_fill;
1490 		if (bh->state == BUF_STATE_EMPTY
1491 		 && common->usb_amount_left > 0) {
1492 			amount = min(common->usb_amount_left, FSG_BUFLEN);
1493 
1494 			/* amount is always divisible by 512, hence by
1495 			 * the bulk-out maxpacket size */
1496 			bh->outreq->length = amount;
1497 			bh->bulk_out_intended_length = amount;
1498 			bh->outreq->short_not_ok = 1;
1499 			START_TRANSFER_OR(common, bulk_out, bh->outreq,
1500 					  &bh->outreq_busy, &bh->state)
1501 				/* Don't know what to do if
1502 				 * common->fsg is NULL */
1503 				return -EIO;
1504 			common->next_buffhd_to_fill = bh->next;
1505 			common->usb_amount_left -= amount;
1506 			continue;
1507 		}
1508 
1509 		/* Otherwise wait for something to happen */
1510 		rc = sleep_thread(common);
1511 		if (rc)
1512 			return rc;
1513 	}
1514 	return 0;
1515 }
1516 
1517 
1518 static int finish_reply(struct fsg_common *common)
1519 {
1520 	struct fsg_buffhd	*bh = common->next_buffhd_to_fill;
1521 	int			rc = 0;
1522 
1523 	switch (common->data_dir) {
1524 	case DATA_DIR_NONE:
1525 		break;			/* Nothing to send */
1526 
1527 	/* If we don't know whether the host wants to read or write,
1528 	 * this must be CB or CBI with an unknown command.  We mustn't
1529 	 * try to send or receive any data.  So stall both bulk pipes
1530 	 * if we can and wait for a reset. */
1531 	case DATA_DIR_UNKNOWN:
1532 		if (!common->can_stall) {
1533 			/* Nothing */
1534 		} else if (fsg_is_set(common)) {
1535 			fsg_set_halt(common->fsg, common->fsg->bulk_out);
1536 			rc = halt_bulk_in_endpoint(common->fsg);
1537 		} else {
1538 			/* Don't know what to do if common->fsg is NULL */
1539 			rc = -EIO;
1540 		}
1541 		break;
1542 
1543 	/* All but the last buffer of data must have already been sent */
1544 	case DATA_DIR_TO_HOST:
1545 		if (common->data_size == 0) {
1546 			/* Nothing to send */
1547 
1548 		/* If there's no residue, simply send the last buffer */
1549 		} else if (common->residue == 0) {
1550 			bh->inreq->zero = 0;
1551 			START_TRANSFER_OR(common, bulk_in, bh->inreq,
1552 					  &bh->inreq_busy, &bh->state)
1553 				return -EIO;
1554 			common->next_buffhd_to_fill = bh->next;
1555 
1556 		/* For Bulk-only, if we're allowed to stall then send the
1557 		 * short packet and halt the bulk-in endpoint.  If we can't
1558 		 * stall, pad out the remaining data with 0's. */
1559 		} else if (common->can_stall) {
1560 			bh->inreq->zero = 1;
1561 			START_TRANSFER_OR(common, bulk_in, bh->inreq,
1562 					  &bh->inreq_busy, &bh->state)
1563 				/* Don't know what to do if
1564 				 * common->fsg is NULL */
1565 				rc = -EIO;
1566 			common->next_buffhd_to_fill = bh->next;
1567 			if (common->fsg)
1568 				rc = halt_bulk_in_endpoint(common->fsg);
1569 		} else if (fsg_is_set(common)) {
1570 			rc = pad_with_zeros(common->fsg);
1571 		} else {
1572 			/* Don't know what to do if common->fsg is NULL */
1573 			rc = -EIO;
1574 		}
1575 		break;
1576 
1577 	/* We have processed all we want from the data the host has sent.
1578 	 * There may still be outstanding bulk-out requests. */
1579 	case DATA_DIR_FROM_HOST:
1580 		if (common->residue == 0) {
1581 			/* Nothing to receive */
1582 
1583 		/* Did the host stop sending unexpectedly early? */
1584 		} else if (common->short_packet_received) {
1585 			raise_exception(common, FSG_STATE_ABORT_BULK_OUT);
1586 			rc = -EINTR;
1587 
1588 		/* We haven't processed all the incoming data.  Even though
1589 		 * we may be allowed to stall, doing so would cause a race.
1590 		 * The controller may already have ACK'ed all the remaining
1591 		 * bulk-out packets, in which case the host wouldn't see a
1592 		 * STALL.  Not realizing the endpoint was halted, it wouldn't
1593 		 * clear the halt -- leading to problems later on. */
1594 #if 0
1595 		} else if (common->can_stall) {
1596 			if (fsg_is_set(common))
1597 				fsg_set_halt(common->fsg,
1598 					     common->fsg->bulk_out);
1599 			raise_exception(common, FSG_STATE_ABORT_BULK_OUT);
1600 			rc = -EINTR;
1601 #endif
1602 
1603 		/* We can't stall.  Read in the excess data and throw it
1604 		 * all away. */
1605 		} else {
1606 			rc = throw_away_data(common);
1607 		}
1608 		break;
1609 	}
1610 	return rc;
1611 }
1612 
1613 
1614 static int send_status(struct fsg_common *common)
1615 {
1616 	struct fsg_lun		*curlun = &common->luns[common->lun];
1617 	struct fsg_buffhd	*bh;
1618 	struct bulk_cs_wrap	*csw;
1619 	int			rc;
1620 	u8			status = USB_STATUS_PASS;
1621 	u32			sd, sdinfo = 0;
1622 
1623 	/* Wait for the next buffer to become available */
1624 	bh = common->next_buffhd_to_fill;
1625 	while (bh->state != BUF_STATE_EMPTY) {
1626 		rc = sleep_thread(common);
1627 		if (rc)
1628 			return rc;
1629 	}
1630 
1631 	if (curlun)
1632 		sd = curlun->sense_data;
1633 	else if (common->bad_lun_okay)
1634 		sd = SS_NO_SENSE;
1635 	else
1636 		sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
1637 
1638 	if (common->phase_error) {
1639 		DBG(common, "sending phase-error status\n");
1640 		status = USB_STATUS_PHASE_ERROR;
1641 		sd = SS_INVALID_COMMAND;
1642 	} else if (sd != SS_NO_SENSE) {
1643 		DBG(common, "sending command-failure status\n");
1644 		status = USB_STATUS_FAIL;
1645 		VDBG(common, "  sense data: SK x%02x, ASC x%02x, ASCQ x%02x;"
1646 			"  info x%x\n",
1647 			SK(sd), ASC(sd), ASCQ(sd), sdinfo);
1648 	}
1649 
1650 	/* Store and send the Bulk-only CSW */
1651 	csw = (void *)bh->buf;
1652 
1653 	csw->Signature = cpu_to_le32(USB_BULK_CS_SIG);
1654 	csw->Tag = common->tag;
1655 	csw->Residue = cpu_to_le32(common->residue);
1656 	csw->Status = status;
1657 
1658 	bh->inreq->length = USB_BULK_CS_WRAP_LEN;
1659 	bh->inreq->zero = 0;
1660 	START_TRANSFER_OR(common, bulk_in, bh->inreq,
1661 			  &bh->inreq_busy, &bh->state)
1662 		/* Don't know what to do if common->fsg is NULL */
1663 		return -EIO;
1664 
1665 	common->next_buffhd_to_fill = bh->next;
1666 	return 0;
1667 }
1668 
1669 
1670 /*-------------------------------------------------------------------------*/
1671 
1672 /* Check whether the command is properly formed and whether its data size
1673  * and direction agree with the values we already have. */
1674 static int check_command(struct fsg_common *common, int cmnd_size,
1675 		enum data_direction data_dir, unsigned int mask,
1676 		int needs_medium, const char *name)
1677 {
1678 	int			i;
1679 	int			lun = common->cmnd[1] >> 5;
1680 	static const char	dirletter[4] = {'u', 'o', 'i', 'n'};
1681 	char			hdlen[20];
1682 	struct fsg_lun		*curlun;
1683 
1684 	hdlen[0] = 0;
1685 	if (common->data_dir != DATA_DIR_UNKNOWN)
1686 		sprintf(hdlen, ", H%c=%u", dirletter[(int) common->data_dir],
1687 				common->data_size);
1688 	VDBG(common, "SCSI command: %s;  Dc=%d, D%c=%u;  Hc=%d%s\n",
1689 	     name, cmnd_size, dirletter[(int) data_dir],
1690 	     common->data_size_from_cmnd, common->cmnd_size, hdlen);
1691 
1692 	/* We can't reply at all until we know the correct data direction
1693 	 * and size. */
1694 	if (common->data_size_from_cmnd == 0)
1695 		data_dir = DATA_DIR_NONE;
1696 	if (common->data_size < common->data_size_from_cmnd) {
1697 		/* Host data size < Device data size is a phase error.
1698 		 * Carry out the command, but only transfer as much as
1699 		 * we are allowed. */
1700 		common->data_size_from_cmnd = common->data_size;
1701 		common->phase_error = 1;
1702 	}
1703 	common->residue = common->data_size;
1704 	common->usb_amount_left = common->data_size;
1705 
1706 	/* Conflicting data directions is a phase error */
1707 	if (common->data_dir != data_dir
1708 	 && common->data_size_from_cmnd > 0) {
1709 		common->phase_error = 1;
1710 		return -EINVAL;
1711 	}
1712 
1713 	/* Verify the length of the command itself */
1714 	if (cmnd_size != common->cmnd_size) {
1715 
1716 		/* Special case workaround: There are plenty of buggy SCSI
1717 		 * implementations. Many have issues with cbw->Length
1718 		 * field passing a wrong command size. For those cases we
1719 		 * always try to work around the problem by using the length
1720 		 * sent by the host side provided it is at least as large
1721 		 * as the correct command length.
1722 		 * Examples of such cases would be MS-Windows, which issues
1723 		 * REQUEST SENSE with cbw->Length == 12 where it should
1724 		 * be 6, and xbox360 issuing INQUIRY, TEST UNIT READY and
1725 		 * REQUEST SENSE with cbw->Length == 10 where it should
1726 		 * be 6 as well.
1727 		 */
1728 		if (cmnd_size <= common->cmnd_size) {
1729 			DBG(common, "%s is buggy! Expected length %d "
1730 			    "but we got %d\n", name,
1731 			    cmnd_size, common->cmnd_size);
1732 			cmnd_size = common->cmnd_size;
1733 		} else {
1734 			common->phase_error = 1;
1735 			return -EINVAL;
1736 		}
1737 	}
1738 
1739 	/* Check that the LUN values are consistent */
1740 	if (common->lun != lun)
1741 		DBG(common, "using LUN %d from CBW, not LUN %d from CDB\n",
1742 		    common->lun, lun);
1743 
1744 	/* Check the LUN */
1745 	if (common->lun >= 0 && common->lun < common->nluns) {
1746 		curlun = &common->luns[common->lun];
1747 		if (common->cmnd[0] != SC_REQUEST_SENSE) {
1748 			curlun->sense_data = SS_NO_SENSE;
1749 			curlun->info_valid = 0;
1750 		}
1751 	} else {
1752 		curlun = NULL;
1753 		common->bad_lun_okay = 0;
1754 
1755 		/* INQUIRY and REQUEST SENSE commands are explicitly allowed
1756 		 * to use unsupported LUNs; all others may not. */
1757 		if (common->cmnd[0] != SC_INQUIRY &&
1758 		    common->cmnd[0] != SC_REQUEST_SENSE) {
1759 			DBG(common, "unsupported LUN %d\n", common->lun);
1760 			return -EINVAL;
1761 		}
1762 	}
1763 #if 0
1764 	/* If a unit attention condition exists, only INQUIRY and
1765 	 * REQUEST SENSE commands are allowed; anything else must fail. */
1766 	if (curlun && curlun->unit_attention_data != SS_NO_SENSE &&
1767 			common->cmnd[0] != SC_INQUIRY &&
1768 			common->cmnd[0] != SC_REQUEST_SENSE) {
1769 		curlun->sense_data = curlun->unit_attention_data;
1770 		curlun->unit_attention_data = SS_NO_SENSE;
1771 		return -EINVAL;
1772 	}
1773 #endif
1774 	/* Check that only command bytes listed in the mask are non-zero */
1775 	common->cmnd[1] &= 0x1f;			/* Mask away the LUN */
1776 	for (i = 1; i < cmnd_size; ++i) {
1777 		if (common->cmnd[i] && !(mask & (1 << i))) {
1778 			if (curlun)
1779 				curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1780 			return -EINVAL;
1781 		}
1782 	}
1783 
1784 	return 0;
1785 }
1786 
1787 
1788 static int do_scsi_command(struct fsg_common *common)
1789 {
1790 	struct fsg_buffhd	*bh;
1791 	int			rc;
1792 	int			reply = -EINVAL;
1793 	int			i;
1794 	static char		unknown[16];
1795 	struct fsg_lun		*curlun = &common->luns[common->lun];
1796 
1797 	dump_cdb(common);
1798 
1799 	/* Wait for the next buffer to become available for data or status */
1800 	bh = common->next_buffhd_to_fill;
1801 	common->next_buffhd_to_drain = bh;
1802 	while (bh->state != BUF_STATE_EMPTY) {
1803 		rc = sleep_thread(common);
1804 		if (rc)
1805 			return rc;
1806 	}
1807 	common->phase_error = 0;
1808 	common->short_packet_received = 0;
1809 
1810 	down_read(&common->filesem);	/* We're using the backing file */
1811 	switch (common->cmnd[0]) {
1812 
1813 	case SC_INQUIRY:
1814 		common->data_size_from_cmnd = common->cmnd[4];
1815 		reply = check_command(common, 6, DATA_DIR_TO_HOST,
1816 				      (1<<4), 0,
1817 				      "INQUIRY");
1818 		if (reply == 0)
1819 			reply = do_inquiry(common, bh);
1820 		break;
1821 
1822 	case SC_MODE_SELECT_6:
1823 		common->data_size_from_cmnd = common->cmnd[4];
1824 		reply = check_command(common, 6, DATA_DIR_FROM_HOST,
1825 				      (1<<1) | (1<<4), 0,
1826 				      "MODE SELECT(6)");
1827 		if (reply == 0)
1828 			reply = do_mode_select(common, bh);
1829 		break;
1830 
1831 	case SC_MODE_SELECT_10:
1832 		common->data_size_from_cmnd =
1833 			get_unaligned_be16(&common->cmnd[7]);
1834 		reply = check_command(common, 10, DATA_DIR_FROM_HOST,
1835 				      (1<<1) | (3<<7), 0,
1836 				      "MODE SELECT(10)");
1837 		if (reply == 0)
1838 			reply = do_mode_select(common, bh);
1839 		break;
1840 
1841 	case SC_MODE_SENSE_6:
1842 		common->data_size_from_cmnd = common->cmnd[4];
1843 		reply = check_command(common, 6, DATA_DIR_TO_HOST,
1844 				      (1<<1) | (1<<2) | (1<<4), 0,
1845 				      "MODE SENSE(6)");
1846 		if (reply == 0)
1847 			reply = do_mode_sense(common, bh);
1848 		break;
1849 
1850 	case SC_MODE_SENSE_10:
1851 		common->data_size_from_cmnd =
1852 			get_unaligned_be16(&common->cmnd[7]);
1853 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1854 				      (1<<1) | (1<<2) | (3<<7), 0,
1855 				      "MODE SENSE(10)");
1856 		if (reply == 0)
1857 			reply = do_mode_sense(common, bh);
1858 		break;
1859 
1860 	case SC_PREVENT_ALLOW_MEDIUM_REMOVAL:
1861 		common->data_size_from_cmnd = 0;
1862 		reply = check_command(common, 6, DATA_DIR_NONE,
1863 				      (1<<4), 0,
1864 				      "PREVENT-ALLOW MEDIUM REMOVAL");
1865 		if (reply == 0)
1866 			reply = do_prevent_allow(common);
1867 		break;
1868 
1869 	case SC_READ_6:
1870 		i = common->cmnd[4];
1871 		common->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
1872 		reply = check_command(common, 6, DATA_DIR_TO_HOST,
1873 				      (7<<1) | (1<<4), 1,
1874 				      "READ(6)");
1875 		if (reply == 0)
1876 			reply = do_read(common);
1877 		break;
1878 
1879 	case SC_READ_10:
1880 		common->data_size_from_cmnd =
1881 				get_unaligned_be16(&common->cmnd[7]) << 9;
1882 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1883 				      (1<<1) | (0xf<<2) | (3<<7), 1,
1884 				      "READ(10)");
1885 		if (reply == 0)
1886 			reply = do_read(common);
1887 		break;
1888 
1889 	case SC_READ_12:
1890 		common->data_size_from_cmnd =
1891 				get_unaligned_be32(&common->cmnd[6]) << 9;
1892 		reply = check_command(common, 12, DATA_DIR_TO_HOST,
1893 				      (1<<1) | (0xf<<2) | (0xf<<6), 1,
1894 				      "READ(12)");
1895 		if (reply == 0)
1896 			reply = do_read(common);
1897 		break;
1898 
1899 	case SC_READ_CAPACITY:
1900 		common->data_size_from_cmnd = 8;
1901 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1902 				      (0xf<<2) | (1<<8), 1,
1903 				      "READ CAPACITY");
1904 		if (reply == 0)
1905 			reply = do_read_capacity(common, bh);
1906 		break;
1907 
1908 	case SC_READ_HEADER:
1909 		if (!common->luns[common->lun].cdrom)
1910 			goto unknown_cmnd;
1911 		common->data_size_from_cmnd =
1912 			get_unaligned_be16(&common->cmnd[7]);
1913 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1914 				      (3<<7) | (0x1f<<1), 1,
1915 				      "READ HEADER");
1916 		if (reply == 0)
1917 			reply = do_read_header(common, bh);
1918 		break;
1919 
1920 	case SC_READ_TOC:
1921 		if (!common->luns[common->lun].cdrom)
1922 			goto unknown_cmnd;
1923 		common->data_size_from_cmnd =
1924 			get_unaligned_be16(&common->cmnd[7]);
1925 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1926 				      (7<<6) | (1<<1), 1,
1927 				      "READ TOC");
1928 		if (reply == 0)
1929 			reply = do_read_toc(common, bh);
1930 		break;
1931 
1932 	case SC_READ_FORMAT_CAPACITIES:
1933 		common->data_size_from_cmnd =
1934 			get_unaligned_be16(&common->cmnd[7]);
1935 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1936 				      (3<<7), 1,
1937 				      "READ FORMAT CAPACITIES");
1938 		if (reply == 0)
1939 			reply = do_read_format_capacities(common, bh);
1940 		break;
1941 
1942 	case SC_REQUEST_SENSE:
1943 		common->data_size_from_cmnd = common->cmnd[4];
1944 		reply = check_command(common, 6, DATA_DIR_TO_HOST,
1945 				      (1<<4), 0,
1946 				      "REQUEST SENSE");
1947 		if (reply == 0)
1948 			reply = do_request_sense(common, bh);
1949 		break;
1950 
1951 	case SC_START_STOP_UNIT:
1952 		common->data_size_from_cmnd = 0;
1953 		reply = check_command(common, 6, DATA_DIR_NONE,
1954 				      (1<<1) | (1<<4), 0,
1955 				      "START-STOP UNIT");
1956 		if (reply == 0)
1957 			reply = do_start_stop(common);
1958 		break;
1959 
1960 	case SC_SYNCHRONIZE_CACHE:
1961 		common->data_size_from_cmnd = 0;
1962 		reply = check_command(common, 10, DATA_DIR_NONE,
1963 				      (0xf<<2) | (3<<7), 1,
1964 				      "SYNCHRONIZE CACHE");
1965 		if (reply == 0)
1966 			reply = do_synchronize_cache(common);
1967 		break;
1968 
1969 	case SC_TEST_UNIT_READY:
1970 		common->data_size_from_cmnd = 0;
1971 		reply = check_command(common, 6, DATA_DIR_NONE,
1972 				0, 1,
1973 				"TEST UNIT READY");
1974 		break;
1975 
1976 	/* Although optional, this command is used by MS-Windows.  We
1977 	 * support a minimal version: BytChk must be 0. */
1978 	case SC_VERIFY:
1979 		common->data_size_from_cmnd = 0;
1980 		reply = check_command(common, 10, DATA_DIR_NONE,
1981 				      (1<<1) | (0xf<<2) | (3<<7), 1,
1982 				      "VERIFY");
1983 		if (reply == 0)
1984 			reply = do_verify(common);
1985 		break;
1986 
1987 	case SC_WRITE_6:
1988 		i = common->cmnd[4];
1989 		common->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
1990 		reply = check_command(common, 6, DATA_DIR_FROM_HOST,
1991 				      (7<<1) | (1<<4), 1,
1992 				      "WRITE(6)");
1993 		if (reply == 0)
1994 			reply = do_write(common);
1995 		break;
1996 
1997 	case SC_WRITE_10:
1998 		common->data_size_from_cmnd =
1999 				get_unaligned_be16(&common->cmnd[7]) << 9;
2000 		reply = check_command(common, 10, DATA_DIR_FROM_HOST,
2001 				      (1<<1) | (0xf<<2) | (3<<7), 1,
2002 				      "WRITE(10)");
2003 		if (reply == 0)
2004 			reply = do_write(common);
2005 		break;
2006 
2007 	case SC_WRITE_12:
2008 		common->data_size_from_cmnd =
2009 				get_unaligned_be32(&common->cmnd[6]) << 9;
2010 		reply = check_command(common, 12, DATA_DIR_FROM_HOST,
2011 				      (1<<1) | (0xf<<2) | (0xf<<6), 1,
2012 				      "WRITE(12)");
2013 		if (reply == 0)
2014 			reply = do_write(common);
2015 		break;
2016 
2017 	/* Some mandatory commands that we recognize but don't implement.
2018 	 * They don't mean much in this setting.  It's left as an exercise
2019 	 * for anyone interested to implement RESERVE and RELEASE in terms
2020 	 * of Posix locks. */
2021 	case SC_FORMAT_UNIT:
2022 	case SC_RELEASE:
2023 	case SC_RESERVE:
2024 	case SC_SEND_DIAGNOSTIC:
2025 		/* Fall through */
2026 
2027 	default:
2028 unknown_cmnd:
2029 		common->data_size_from_cmnd = 0;
2030 		sprintf(unknown, "Unknown x%02x", common->cmnd[0]);
2031 		reply = check_command(common, common->cmnd_size,
2032 				      DATA_DIR_UNKNOWN, 0xff, 0, unknown);
2033 		if (reply == 0) {
2034 			curlun->sense_data = SS_INVALID_COMMAND;
2035 			reply = -EINVAL;
2036 		}
2037 		break;
2038 	}
2039 	up_read(&common->filesem);
2040 
2041 	if (reply == -EINTR)
2042 		return -EINTR;
2043 
2044 	/* Set up the single reply buffer for finish_reply() */
2045 	if (reply == -EINVAL)
2046 		reply = 0;		/* Error reply length */
2047 	if (reply >= 0 && common->data_dir == DATA_DIR_TO_HOST) {
2048 		reply = min((u32) reply, common->data_size_from_cmnd);
2049 		bh->inreq->length = reply;
2050 		bh->state = BUF_STATE_FULL;
2051 		common->residue -= reply;
2052 	}				/* Otherwise it's already set */
2053 
2054 	return 0;
2055 }
2056 
2057 /*-------------------------------------------------------------------------*/
2058 
2059 static int received_cbw(struct fsg_dev *fsg, struct fsg_buffhd *bh)
2060 {
2061 	struct usb_request	*req = bh->outreq;
2062 	struct fsg_bulk_cb_wrap	*cbw = req->buf;
2063 	struct fsg_common	*common = fsg->common;
2064 
2065 	/* Was this a real packet?  Should it be ignored? */
2066 	if (req->status || test_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags))
2067 		return -EINVAL;
2068 
2069 	/* Is the CBW valid? */
2070 	if (req->actual != USB_BULK_CB_WRAP_LEN ||
2071 			cbw->Signature != cpu_to_le32(
2072 				USB_BULK_CB_SIG)) {
2073 		DBG(fsg, "invalid CBW: len %u sig 0x%x\n",
2074 				req->actual,
2075 				le32_to_cpu(cbw->Signature));
2076 
2077 		/* The Bulk-only spec says we MUST stall the IN endpoint
2078 		 * (6.6.1), so it's unavoidable.  It also says we must
2079 		 * retain this state until the next reset, but there's
2080 		 * no way to tell the controller driver it should ignore
2081 		 * Clear-Feature(HALT) requests.
2082 		 *
2083 		 * We aren't required to halt the OUT endpoint; instead
2084 		 * we can simply accept and discard any data received
2085 		 * until the next reset. */
2086 		wedge_bulk_in_endpoint(fsg);
2087 		set_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
2088 		return -EINVAL;
2089 	}
2090 
2091 	/* Is the CBW meaningful? */
2092 	if (cbw->Lun >= FSG_MAX_LUNS || cbw->Flags & ~USB_BULK_IN_FLAG ||
2093 			cbw->Length <= 0 || cbw->Length > MAX_COMMAND_SIZE) {
2094 		DBG(fsg, "non-meaningful CBW: lun = %u, flags = 0x%x, "
2095 				"cmdlen %u\n",
2096 				cbw->Lun, cbw->Flags, cbw->Length);
2097 
2098 		/* We can do anything we want here, so let's stall the
2099 		 * bulk pipes if we are allowed to. */
2100 		if (common->can_stall) {
2101 			fsg_set_halt(fsg, fsg->bulk_out);
2102 			halt_bulk_in_endpoint(fsg);
2103 		}
2104 		return -EINVAL;
2105 	}
2106 
2107 	/* Save the command for later */
2108 	common->cmnd_size = cbw->Length;
2109 	memcpy(common->cmnd, cbw->CDB, common->cmnd_size);
2110 	if (cbw->Flags & USB_BULK_IN_FLAG)
2111 		common->data_dir = DATA_DIR_TO_HOST;
2112 	else
2113 		common->data_dir = DATA_DIR_FROM_HOST;
2114 	common->data_size = le32_to_cpu(cbw->DataTransferLength);
2115 	if (common->data_size == 0)
2116 		common->data_dir = DATA_DIR_NONE;
2117 	common->lun = cbw->Lun;
2118 	common->tag = cbw->Tag;
2119 	return 0;
2120 }
2121 
2122 
2123 static int get_next_command(struct fsg_common *common)
2124 {
2125 	struct fsg_buffhd	*bh;
2126 	int			rc = 0;
2127 
2128 	/* Wait for the next buffer to become available */
2129 	bh = common->next_buffhd_to_fill;
2130 	while (bh->state != BUF_STATE_EMPTY) {
2131 		rc = sleep_thread(common);
2132 		if (rc)
2133 			return rc;
2134 	}
2135 
2136 	/* Queue a request to read a Bulk-only CBW */
2137 	set_bulk_out_req_length(common, bh, USB_BULK_CB_WRAP_LEN);
2138 	bh->outreq->short_not_ok = 1;
2139 	START_TRANSFER_OR(common, bulk_out, bh->outreq,
2140 			  &bh->outreq_busy, &bh->state)
2141 		/* Don't know what to do if common->fsg is NULL */
2142 		return -EIO;
2143 
2144 	/* We will drain the buffer in software, which means we
2145 	 * can reuse it for the next filling.  No need to advance
2146 	 * next_buffhd_to_fill. */
2147 
2148 	/* Wait for the CBW to arrive */
2149 	while (bh->state != BUF_STATE_FULL) {
2150 		rc = sleep_thread(common);
2151 		if (rc)
2152 			return rc;
2153 	}
2154 
2155 	rc = fsg_is_set(common) ? received_cbw(common->fsg, bh) : -EIO;
2156 	bh->state = BUF_STATE_EMPTY;
2157 
2158 	return rc;
2159 }
2160 
2161 
2162 /*-------------------------------------------------------------------------*/
2163 
2164 static int enable_endpoint(struct fsg_common *common, struct usb_ep *ep,
2165 		const struct usb_endpoint_descriptor *d)
2166 {
2167 	int	rc;
2168 
2169 	ep->driver_data = common;
2170 	rc = usb_ep_enable(ep, d);
2171 	if (rc)
2172 		ERROR(common, "can't enable %s, result %d\n", ep->name, rc);
2173 	return rc;
2174 }
2175 
2176 static int alloc_request(struct fsg_common *common, struct usb_ep *ep,
2177 		struct usb_request **preq)
2178 {
2179 	*preq = usb_ep_alloc_request(ep, GFP_ATOMIC);
2180 	if (*preq)
2181 		return 0;
2182 	ERROR(common, "can't allocate request for %s\n", ep->name);
2183 	return -ENOMEM;
2184 }
2185 
2186 /* Reset interface setting and re-init endpoint state (toggle etc). */
2187 static int do_set_interface(struct fsg_common *common, struct fsg_dev *new_fsg)
2188 {
2189 	const struct usb_endpoint_descriptor *d;
2190 	struct fsg_dev *fsg;
2191 	int i, rc = 0;
2192 
2193 	if (common->running)
2194 		DBG(common, "reset interface\n");
2195 
2196 reset:
2197 	/* Deallocate the requests */
2198 	if (common->fsg) {
2199 		fsg = common->fsg;
2200 
2201 		for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
2202 			struct fsg_buffhd *bh = &common->buffhds[i];
2203 
2204 			if (bh->inreq) {
2205 				usb_ep_free_request(fsg->bulk_in, bh->inreq);
2206 				bh->inreq = NULL;
2207 			}
2208 			if (bh->outreq) {
2209 				usb_ep_free_request(fsg->bulk_out, bh->outreq);
2210 				bh->outreq = NULL;
2211 			}
2212 		}
2213 
2214 		/* Disable the endpoints */
2215 		if (fsg->bulk_in_enabled) {
2216 			usb_ep_disable(fsg->bulk_in);
2217 			fsg->bulk_in_enabled = 0;
2218 		}
2219 		if (fsg->bulk_out_enabled) {
2220 			usb_ep_disable(fsg->bulk_out);
2221 			fsg->bulk_out_enabled = 0;
2222 		}
2223 
2224 		common->fsg = NULL;
2225 		/* wake_up(&common->fsg_wait); */
2226 	}
2227 
2228 	common->running = 0;
2229 	if (!new_fsg || rc)
2230 		return rc;
2231 
2232 	common->fsg = new_fsg;
2233 	fsg = common->fsg;
2234 
2235 	/* Enable the endpoints */
2236 	d = fsg_ep_desc(common->gadget,
2237 			&fsg_fs_bulk_in_desc, &fsg_hs_bulk_in_desc);
2238 	rc = enable_endpoint(common, fsg->bulk_in, d);
2239 	if (rc)
2240 		goto reset;
2241 	fsg->bulk_in_enabled = 1;
2242 
2243 	d = fsg_ep_desc(common->gadget,
2244 			&fsg_fs_bulk_out_desc, &fsg_hs_bulk_out_desc);
2245 	rc = enable_endpoint(common, fsg->bulk_out, d);
2246 	if (rc)
2247 		goto reset;
2248 	fsg->bulk_out_enabled = 1;
2249 	common->bulk_out_maxpacket =
2250 				le16_to_cpu(get_unaligned(&d->wMaxPacketSize));
2251 	clear_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
2252 
2253 	/* Allocate the requests */
2254 	for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
2255 		struct fsg_buffhd	*bh = &common->buffhds[i];
2256 
2257 		rc = alloc_request(common, fsg->bulk_in, &bh->inreq);
2258 		if (rc)
2259 			goto reset;
2260 		rc = alloc_request(common, fsg->bulk_out, &bh->outreq);
2261 		if (rc)
2262 			goto reset;
2263 		bh->inreq->buf = bh->outreq->buf = bh->buf;
2264 		bh->inreq->context = bh->outreq->context = bh;
2265 		bh->inreq->complete = bulk_in_complete;
2266 		bh->outreq->complete = bulk_out_complete;
2267 	}
2268 
2269 	common->running = 1;
2270 
2271 	return rc;
2272 }
2273 
2274 
2275 /****************************** ALT CONFIGS ******************************/
2276 
2277 
2278 static int fsg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
2279 {
2280 	struct fsg_dev *fsg = fsg_from_func(f);
2281 	fsg->common->new_fsg = fsg;
2282 	raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
2283 	return 0;
2284 }
2285 
2286 static void fsg_disable(struct usb_function *f)
2287 {
2288 	struct fsg_dev *fsg = fsg_from_func(f);
2289 	fsg->common->new_fsg = NULL;
2290 	raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
2291 }
2292 
2293 /*-------------------------------------------------------------------------*/
2294 
2295 static void handle_exception(struct fsg_common *common)
2296 {
2297 	int			i;
2298 	struct fsg_buffhd	*bh;
2299 	enum fsg_state		old_state;
2300 	struct fsg_lun		*curlun;
2301 	unsigned int		exception_req_tag;
2302 
2303 	/* Cancel all the pending transfers */
2304 	if (common->fsg) {
2305 		for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
2306 			bh = &common->buffhds[i];
2307 			if (bh->inreq_busy)
2308 				usb_ep_dequeue(common->fsg->bulk_in, bh->inreq);
2309 			if (bh->outreq_busy)
2310 				usb_ep_dequeue(common->fsg->bulk_out,
2311 					       bh->outreq);
2312 		}
2313 
2314 		/* Wait until everything is idle */
2315 		for (;;) {
2316 			int num_active = 0;
2317 			for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
2318 				bh = &common->buffhds[i];
2319 				num_active += bh->inreq_busy + bh->outreq_busy;
2320 			}
2321 			if (num_active == 0)
2322 				break;
2323 			if (sleep_thread(common))
2324 				return;
2325 		}
2326 
2327 		/* Clear out the controller's fifos */
2328 		if (common->fsg->bulk_in_enabled)
2329 			usb_ep_fifo_flush(common->fsg->bulk_in);
2330 		if (common->fsg->bulk_out_enabled)
2331 			usb_ep_fifo_flush(common->fsg->bulk_out);
2332 	}
2333 
2334 	/* Reset the I/O buffer states and pointers, the SCSI
2335 	 * state, and the exception.  Then invoke the handler. */
2336 
2337 	for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
2338 		bh = &common->buffhds[i];
2339 		bh->state = BUF_STATE_EMPTY;
2340 	}
2341 	common->next_buffhd_to_fill = &common->buffhds[0];
2342 	common->next_buffhd_to_drain = &common->buffhds[0];
2343 	exception_req_tag = common->exception_req_tag;
2344 	old_state = common->state;
2345 
2346 	if (old_state == FSG_STATE_ABORT_BULK_OUT)
2347 		common->state = FSG_STATE_STATUS_PHASE;
2348 	else {
2349 		for (i = 0; i < common->nluns; ++i) {
2350 			curlun = &common->luns[i];
2351 			curlun->sense_data = SS_NO_SENSE;
2352 			curlun->info_valid = 0;
2353 		}
2354 		common->state = FSG_STATE_IDLE;
2355 	}
2356 
2357 	/* Carry out any extra actions required for the exception */
2358 	switch (old_state) {
2359 	case FSG_STATE_ABORT_BULK_OUT:
2360 		send_status(common);
2361 
2362 		if (common->state == FSG_STATE_STATUS_PHASE)
2363 			common->state = FSG_STATE_IDLE;
2364 		break;
2365 
2366 	case FSG_STATE_RESET:
2367 		/* In case we were forced against our will to halt a
2368 		 * bulk endpoint, clear the halt now.  (The SuperH UDC
2369 		 * requires this.) */
2370 		if (!fsg_is_set(common))
2371 			break;
2372 		if (test_and_clear_bit(IGNORE_BULK_OUT,
2373 				       &common->fsg->atomic_bitflags))
2374 			usb_ep_clear_halt(common->fsg->bulk_in);
2375 
2376 		if (common->ep0_req_tag == exception_req_tag)
2377 			ep0_queue(common);	/* Complete the status stage */
2378 
2379 		break;
2380 
2381 	case FSG_STATE_CONFIG_CHANGE:
2382 		do_set_interface(common, common->new_fsg);
2383 		break;
2384 
2385 	case FSG_STATE_EXIT:
2386 	case FSG_STATE_TERMINATED:
2387 		do_set_interface(common, NULL);		/* Free resources */
2388 		common->state = FSG_STATE_TERMINATED;	/* Stop the thread */
2389 		break;
2390 
2391 	case FSG_STATE_INTERFACE_CHANGE:
2392 	case FSG_STATE_DISCONNECT:
2393 	case FSG_STATE_COMMAND_PHASE:
2394 	case FSG_STATE_DATA_PHASE:
2395 	case FSG_STATE_STATUS_PHASE:
2396 	case FSG_STATE_IDLE:
2397 		break;
2398 	}
2399 }
2400 
2401 /*-------------------------------------------------------------------------*/
2402 
2403 int fsg_main_thread(void *common_)
2404 {
2405 	int ret;
2406 	struct fsg_common	*common = the_fsg_common;
2407 	/* The main loop */
2408 	do {
2409 		if (exception_in_progress(common)) {
2410 			handle_exception(common);
2411 			continue;
2412 		}
2413 
2414 		if (!common->running) {
2415 			ret = sleep_thread(common);
2416 			if (ret)
2417 				return ret;
2418 
2419 			continue;
2420 		}
2421 
2422 		ret = get_next_command(common);
2423 		if (ret)
2424 			return ret;
2425 
2426 		if (!exception_in_progress(common))
2427 			common->state = FSG_STATE_DATA_PHASE;
2428 
2429 		if (do_scsi_command(common) || finish_reply(common))
2430 			continue;
2431 
2432 		if (!exception_in_progress(common))
2433 			common->state = FSG_STATE_STATUS_PHASE;
2434 
2435 		if (send_status(common))
2436 			continue;
2437 
2438 		if (!exception_in_progress(common))
2439 			common->state = FSG_STATE_IDLE;
2440 	} while (0);
2441 
2442 	common->thread_task = NULL;
2443 
2444 	return 0;
2445 }
2446 
2447 static void fsg_common_release(struct kref *ref);
2448 
2449 static struct fsg_common *fsg_common_init(struct fsg_common *common,
2450 					  struct usb_composite_dev *cdev)
2451 {
2452 	struct usb_gadget *gadget = cdev->gadget;
2453 	struct fsg_buffhd *bh;
2454 	struct fsg_lun *curlun;
2455 	int nluns, i, rc;
2456 
2457 	/* Find out how many LUNs there should be */
2458 	nluns = 1;
2459 	if (nluns < 1 || nluns > FSG_MAX_LUNS) {
2460 		printf("invalid number of LUNs: %u\n", nluns);
2461 		return ERR_PTR(-EINVAL);
2462 	}
2463 
2464 	/* Allocate? */
2465 	if (!common) {
2466 		common = calloc(sizeof(*common), 1);
2467 		if (!common)
2468 			return ERR_PTR(-ENOMEM);
2469 		common->free_storage_on_release = 1;
2470 	} else {
2471 		memset(common, 0, sizeof(*common));
2472 		common->free_storage_on_release = 0;
2473 	}
2474 
2475 	common->ops = NULL;
2476 	common->private_data = NULL;
2477 
2478 	common->gadget = gadget;
2479 	common->ep0 = gadget->ep0;
2480 	common->ep0req = cdev->req;
2481 
2482 	/* Maybe allocate device-global string IDs, and patch descriptors */
2483 	if (fsg_strings[FSG_STRING_INTERFACE].id == 0) {
2484 		rc = usb_string_id(cdev);
2485 		if (unlikely(rc < 0))
2486 			goto error_release;
2487 		fsg_strings[FSG_STRING_INTERFACE].id = rc;
2488 		fsg_intf_desc.iInterface = rc;
2489 	}
2490 
2491 	/* Create the LUNs, open their backing files, and register the
2492 	 * LUN devices in sysfs. */
2493 	curlun = calloc(nluns, sizeof *curlun);
2494 	if (!curlun) {
2495 		rc = -ENOMEM;
2496 		goto error_release;
2497 	}
2498 	common->nluns = nluns;
2499 
2500 	for (i = 0; i < nluns; i++) {
2501 		common->luns[i].removable = 1;
2502 
2503 		rc = fsg_lun_open(&common->luns[i], "");
2504 		if (rc)
2505 			goto error_luns;
2506 	}
2507 	common->lun = 0;
2508 
2509 	/* Data buffers cyclic list */
2510 	bh = common->buffhds;
2511 
2512 	i = FSG_NUM_BUFFERS;
2513 	goto buffhds_first_it;
2514 	do {
2515 		bh->next = bh + 1;
2516 		++bh;
2517 buffhds_first_it:
2518 		bh->inreq_busy = 0;
2519 		bh->outreq_busy = 0;
2520 		bh->buf = memalign(CONFIG_SYS_CACHELINE_SIZE, FSG_BUFLEN);
2521 		if (unlikely(!bh->buf)) {
2522 			rc = -ENOMEM;
2523 			goto error_release;
2524 		}
2525 	} while (--i);
2526 	bh->next = common->buffhds;
2527 
2528 	snprintf(common->inquiry_string, sizeof common->inquiry_string,
2529 		 "%-8s%-16s%04x",
2530 		 "Linux   ",
2531 		 "File-Store Gadget",
2532 		 0xffff);
2533 
2534 	/* Some peripheral controllers are known not to be able to
2535 	 * halt bulk endpoints correctly.  If one of them is present,
2536 	 * disable stalls.
2537 	 */
2538 
2539 	/* Tell the thread to start working */
2540 	common->thread_task =
2541 		kthread_create(fsg_main_thread, common,
2542 			       OR(cfg->thread_name, "file-storage"));
2543 	if (IS_ERR(common->thread_task)) {
2544 		rc = PTR_ERR(common->thread_task);
2545 		goto error_release;
2546 	}
2547 
2548 #undef OR
2549 	/* Information */
2550 	INFO(common, FSG_DRIVER_DESC ", version: " FSG_DRIVER_VERSION "\n");
2551 	INFO(common, "Number of LUNs=%d\n", common->nluns);
2552 
2553 	return common;
2554 
2555 error_luns:
2556 	common->nluns = i + 1;
2557 error_release:
2558 	common->state = FSG_STATE_TERMINATED;	/* The thread is dead */
2559 	/* Call fsg_common_release() directly, ref might be not
2560 	 * initialised */
2561 	fsg_common_release(&common->ref);
2562 	return ERR_PTR(rc);
2563 }
2564 
2565 static void fsg_common_release(struct kref *ref)
2566 {
2567 	struct fsg_common *common = container_of(ref, struct fsg_common, ref);
2568 
2569 	/* If the thread isn't already dead, tell it to exit now */
2570 	if (common->state != FSG_STATE_TERMINATED) {
2571 		raise_exception(common, FSG_STATE_EXIT);
2572 		wait_for_completion(&common->thread_notifier);
2573 	}
2574 
2575 	if (likely(common->luns)) {
2576 		struct fsg_lun *lun = common->luns;
2577 		unsigned i = common->nluns;
2578 
2579 		/* In error recovery common->nluns may be zero. */
2580 		for (; i; --i, ++lun)
2581 			fsg_lun_close(lun);
2582 
2583 		kfree(common->luns);
2584 	}
2585 
2586 	{
2587 		struct fsg_buffhd *bh = common->buffhds;
2588 		unsigned i = FSG_NUM_BUFFERS;
2589 		do {
2590 			kfree(bh->buf);
2591 		} while (++bh, --i);
2592 	}
2593 
2594 	if (common->free_storage_on_release)
2595 		kfree(common);
2596 }
2597 
2598 
2599 /*-------------------------------------------------------------------------*/
2600 
2601 /**
2602  * usb_copy_descriptors - copy a vector of USB descriptors
2603  * @src: null-terminated vector to copy
2604  * Context: initialization code, which may sleep
2605  *
2606  * This makes a copy of a vector of USB descriptors.  Its primary use
2607  * is to support usb_function objects which can have multiple copies,
2608  * each needing different descriptors.  Functions may have static
2609  * tables of descriptors, which are used as templates and customized
2610  * with identifiers (for interfaces, strings, endpoints, and more)
2611  * as needed by a given function instance.
2612  */
2613 struct usb_descriptor_header **
2614 usb_copy_descriptors(struct usb_descriptor_header **src)
2615 {
2616 	struct usb_descriptor_header **tmp;
2617 	unsigned bytes;
2618 	unsigned n_desc;
2619 	void *mem;
2620 	struct usb_descriptor_header **ret;
2621 
2622 	/* count descriptors and their sizes; then add vector size */
2623 	for (bytes = 0, n_desc = 0, tmp = src; *tmp; tmp++, n_desc++)
2624 		bytes += (*tmp)->bLength;
2625 	bytes += (n_desc + 1) * sizeof(*tmp);
2626 
2627 	mem = memalign(CONFIG_SYS_CACHELINE_SIZE, bytes);
2628 	if (!mem)
2629 		return NULL;
2630 
2631 	/* fill in pointers starting at "tmp",
2632 	 * to descriptors copied starting at "mem";
2633 	 * and return "ret"
2634 	 */
2635 	tmp = mem;
2636 	ret = mem;
2637 	mem += (n_desc + 1) * sizeof(*tmp);
2638 	while (*src) {
2639 		memcpy(mem, *src, (*src)->bLength);
2640 		*tmp = mem;
2641 		tmp++;
2642 		mem += (*src)->bLength;
2643 		src++;
2644 	}
2645 	*tmp = NULL;
2646 
2647 	return ret;
2648 }
2649 
2650 static void fsg_unbind(struct usb_configuration *c, struct usb_function *f)
2651 {
2652 	struct fsg_dev		*fsg = fsg_from_func(f);
2653 
2654 	DBG(fsg, "unbind\n");
2655 	if (fsg->common->fsg == fsg) {
2656 		fsg->common->new_fsg = NULL;
2657 		raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
2658 	}
2659 
2660 	free(fsg->function.descriptors);
2661 	free(fsg->function.hs_descriptors);
2662 	kfree(fsg);
2663 }
2664 
2665 static int fsg_bind(struct usb_configuration *c, struct usb_function *f)
2666 {
2667 	struct fsg_dev		*fsg = fsg_from_func(f);
2668 	struct usb_gadget	*gadget = c->cdev->gadget;
2669 	int			i;
2670 	struct usb_ep		*ep;
2671 	fsg->gadget = gadget;
2672 
2673 	/* New interface */
2674 	i = usb_interface_id(c, f);
2675 	if (i < 0)
2676 		return i;
2677 	fsg_intf_desc.bInterfaceNumber = i;
2678 	fsg->interface_number = i;
2679 
2680 	/* Find all the endpoints we will use */
2681 	ep = usb_ep_autoconfig(gadget, &fsg_fs_bulk_in_desc);
2682 	if (!ep)
2683 		goto autoconf_fail;
2684 	ep->driver_data = fsg->common;	/* claim the endpoint */
2685 	fsg->bulk_in = ep;
2686 
2687 	ep = usb_ep_autoconfig(gadget, &fsg_fs_bulk_out_desc);
2688 	if (!ep)
2689 		goto autoconf_fail;
2690 	ep->driver_data = fsg->common;	/* claim the endpoint */
2691 	fsg->bulk_out = ep;
2692 
2693 	/* Copy descriptors */
2694 	f->descriptors = usb_copy_descriptors(fsg_fs_function);
2695 	if (unlikely(!f->descriptors))
2696 		return -ENOMEM;
2697 
2698 	if (gadget_is_dualspeed(gadget)) {
2699 		/* Assume endpoint addresses are the same for both speeds */
2700 		fsg_hs_bulk_in_desc.bEndpointAddress =
2701 			fsg_fs_bulk_in_desc.bEndpointAddress;
2702 		fsg_hs_bulk_out_desc.bEndpointAddress =
2703 			fsg_fs_bulk_out_desc.bEndpointAddress;
2704 		f->hs_descriptors = usb_copy_descriptors(fsg_hs_function);
2705 		if (unlikely(!f->hs_descriptors)) {
2706 			free(f->descriptors);
2707 			return -ENOMEM;
2708 		}
2709 	}
2710 	return 0;
2711 
2712 autoconf_fail:
2713 	ERROR(fsg, "unable to autoconfigure all endpoints\n");
2714 	return -ENOTSUPP;
2715 }
2716 
2717 
2718 /****************************** ADD FUNCTION ******************************/
2719 
2720 static struct usb_gadget_strings *fsg_strings_array[] = {
2721 	&fsg_stringtab,
2722 	NULL,
2723 };
2724 
2725 static int fsg_bind_config(struct usb_composite_dev *cdev,
2726 			   struct usb_configuration *c,
2727 			   struct fsg_common *common)
2728 {
2729 	struct fsg_dev *fsg;
2730 	int rc;
2731 
2732 	fsg = calloc(1, sizeof *fsg);
2733 	if (!fsg)
2734 		return -ENOMEM;
2735 	fsg->function.name        = FSG_DRIVER_DESC;
2736 	fsg->function.strings     = fsg_strings_array;
2737 	fsg->function.bind        = fsg_bind;
2738 	fsg->function.unbind      = fsg_unbind;
2739 	fsg->function.setup       = fsg_setup;
2740 	fsg->function.set_alt     = fsg_set_alt;
2741 	fsg->function.disable     = fsg_disable;
2742 
2743 	fsg->common               = common;
2744 	common->fsg               = fsg;
2745 	/* Our caller holds a reference to common structure so we
2746 	 * don't have to be worry about it being freed until we return
2747 	 * from this function.  So instead of incrementing counter now
2748 	 * and decrement in error recovery we increment it only when
2749 	 * call to usb_add_function() was successful. */
2750 
2751 	rc = usb_add_function(c, &fsg->function);
2752 
2753 	if (rc)
2754 		kfree(fsg);
2755 
2756 	return rc;
2757 }
2758 
2759 int fsg_add(struct usb_configuration *c)
2760 {
2761 	struct fsg_common *fsg_common;
2762 
2763 	fsg_common = fsg_common_init(NULL, c->cdev);
2764 
2765 	fsg_common->vendor_name = 0;
2766 	fsg_common->product_name = 0;
2767 	fsg_common->release = 0xffff;
2768 
2769 	fsg_common->ops = NULL;
2770 	fsg_common->private_data = NULL;
2771 
2772 	the_fsg_common = fsg_common;
2773 
2774 	return fsg_bind_config(c->cdev, c, fsg_common);
2775 }
2776 
2777 int fsg_init(struct ums *ums_dev)
2778 {
2779 	ums = ums_dev;
2780 
2781 	return 0;
2782 }
2783 
2784 DECLARE_GADGET_BIND_CALLBACK(usb_dnl_ums, fsg_add);
2785