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 <usb.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 
259 /*------------------------------------------------------------------------*/
260 
261 #define FSG_DRIVER_DESC	"Mass Storage Function"
262 #define FSG_DRIVER_VERSION	"2012/06/5"
263 
264 static const char fsg_string_interface[] = "Mass Storage";
265 
266 #define FSG_NO_INTR_EP 1
267 #define FSG_NO_DEVICE_STRINGS    1
268 #define FSG_NO_OTG               1
269 #define FSG_NO_INTR_EP           1
270 
271 #include "storage_common.c"
272 
273 /*-------------------------------------------------------------------------*/
274 
275 #define GFP_ATOMIC ((gfp_t) 0)
276 #define PAGE_CACHE_SHIFT	12
277 #define PAGE_CACHE_SIZE		(1 << PAGE_CACHE_SHIFT)
278 #define kthread_create(...)	__builtin_return_address(0)
279 #define wait_for_completion(...) do {} while (0)
280 
281 struct kref {int x; };
282 struct completion {int x; };
283 
284 inline void set_bit(int nr, volatile void *addr)
285 {
286 	int	mask;
287 	unsigned int *a = (unsigned int *) addr;
288 
289 	a += nr >> 5;
290 	mask = 1 << (nr & 0x1f);
291 	*a |= mask;
292 }
293 
294 inline void clear_bit(int nr, volatile void *addr)
295 {
296 	int	mask;
297 	unsigned int *a = (unsigned int *) addr;
298 
299 	a += nr >> 5;
300 	mask = 1 << (nr & 0x1f);
301 	*a &= ~mask;
302 }
303 
304 struct fsg_dev;
305 struct fsg_common;
306 
307 /* Data shared by all the FSG instances. */
308 struct fsg_common {
309 	struct usb_gadget	*gadget;
310 	struct fsg_dev		*fsg, *new_fsg;
311 
312 	struct usb_ep		*ep0;		/* Copy of gadget->ep0 */
313 	struct usb_request	*ep0req;	/* Copy of cdev->req */
314 	unsigned int		ep0_req_tag;
315 
316 	struct fsg_buffhd	*next_buffhd_to_fill;
317 	struct fsg_buffhd	*next_buffhd_to_drain;
318 	struct fsg_buffhd	buffhds[FSG_NUM_BUFFERS];
319 
320 	int			cmnd_size;
321 	u8			cmnd[MAX_COMMAND_SIZE];
322 
323 	unsigned int		nluns;
324 	unsigned int		lun;
325 	struct fsg_lun          luns[FSG_MAX_LUNS];
326 
327 	unsigned int		bulk_out_maxpacket;
328 	enum fsg_state		state;		/* For exception handling */
329 	unsigned int		exception_req_tag;
330 
331 	enum data_direction	data_dir;
332 	u32			data_size;
333 	u32			data_size_from_cmnd;
334 	u32			tag;
335 	u32			residue;
336 	u32			usb_amount_left;
337 
338 	unsigned int		can_stall:1;
339 	unsigned int		free_storage_on_release:1;
340 	unsigned int		phase_error:1;
341 	unsigned int		short_packet_received:1;
342 	unsigned int		bad_lun_okay:1;
343 	unsigned int		running:1;
344 
345 	int			thread_wakeup_needed;
346 	struct completion	thread_notifier;
347 	struct task_struct	*thread_task;
348 
349 	/* Callback functions. */
350 	const struct fsg_operations	*ops;
351 	/* Gadget's private data. */
352 	void			*private_data;
353 
354 	const char *vendor_name;		/*  8 characters or less */
355 	const char *product_name;		/* 16 characters or less */
356 	u16 release;
357 
358 	/* Vendor (8 chars), product (16 chars), release (4
359 	 * hexadecimal digits) and NUL byte */
360 	char inquiry_string[8 + 16 + 4 + 1];
361 
362 	struct kref		ref;
363 };
364 
365 struct fsg_config {
366 	unsigned nluns;
367 	struct fsg_lun_config {
368 		const char *filename;
369 		char ro;
370 		char removable;
371 		char cdrom;
372 		char nofua;
373 	} luns[FSG_MAX_LUNS];
374 
375 	/* Callback functions. */
376 	const struct fsg_operations     *ops;
377 	/* Gadget's private data. */
378 	void			*private_data;
379 
380 	const char *vendor_name;		/*  8 characters or less */
381 	const char *product_name;		/* 16 characters or less */
382 
383 	char			can_stall;
384 };
385 
386 struct fsg_dev {
387 	struct usb_function	function;
388 	struct usb_gadget	*gadget;	/* Copy of cdev->gadget */
389 	struct fsg_common	*common;
390 
391 	u16			interface_number;
392 
393 	unsigned int		bulk_in_enabled:1;
394 	unsigned int		bulk_out_enabled:1;
395 
396 	unsigned long		atomic_bitflags;
397 #define IGNORE_BULK_OUT		0
398 
399 	struct usb_ep		*bulk_in;
400 	struct usb_ep		*bulk_out;
401 };
402 
403 
404 static inline int __fsg_is_set(struct fsg_common *common,
405 			       const char *func, unsigned line)
406 {
407 	if (common->fsg)
408 		return 1;
409 	ERROR(common, "common->fsg is NULL in %s at %u\n", func, line);
410 	WARN_ON(1);
411 	return 0;
412 }
413 
414 #define fsg_is_set(common) likely(__fsg_is_set(common, __func__, __LINE__))
415 
416 
417 static inline struct fsg_dev *fsg_from_func(struct usb_function *f)
418 {
419 	return container_of(f, struct fsg_dev, function);
420 }
421 
422 
423 typedef void (*fsg_routine_t)(struct fsg_dev *);
424 
425 static int exception_in_progress(struct fsg_common *common)
426 {
427 	return common->state > FSG_STATE_IDLE;
428 }
429 
430 /* Make bulk-out requests be divisible by the maxpacket size */
431 static void set_bulk_out_req_length(struct fsg_common *common,
432 		struct fsg_buffhd *bh, unsigned int length)
433 {
434 	unsigned int	rem;
435 
436 	bh->bulk_out_intended_length = length;
437 	rem = length % common->bulk_out_maxpacket;
438 	if (rem > 0)
439 		length += common->bulk_out_maxpacket - rem;
440 	bh->outreq->length = length;
441 }
442 
443 /*-------------------------------------------------------------------------*/
444 
445 struct ums *ums;
446 struct fsg_common *the_fsg_common;
447 
448 static int fsg_set_halt(struct fsg_dev *fsg, struct usb_ep *ep)
449 {
450 	const char	*name;
451 
452 	if (ep == fsg->bulk_in)
453 		name = "bulk-in";
454 	else if (ep == fsg->bulk_out)
455 		name = "bulk-out";
456 	else
457 		name = ep->name;
458 	DBG(fsg, "%s set halt\n", name);
459 	return usb_ep_set_halt(ep);
460 }
461 
462 /*-------------------------------------------------------------------------*/
463 
464 /* These routines may be called in process context or in_irq */
465 
466 /* Caller must hold fsg->lock */
467 static void wakeup_thread(struct fsg_common *common)
468 {
469 	common->thread_wakeup_needed = 1;
470 }
471 
472 static void raise_exception(struct fsg_common *common, enum fsg_state new_state)
473 {
474 	/* Do nothing if a higher-priority exception is already in progress.
475 	 * If a lower-or-equal priority exception is in progress, preempt it
476 	 * and notify the main thread by sending it a signal. */
477 	if (common->state <= new_state) {
478 		common->exception_req_tag = common->ep0_req_tag;
479 		common->state = new_state;
480 		common->thread_wakeup_needed = 1;
481 	}
482 }
483 
484 /*-------------------------------------------------------------------------*/
485 
486 static int ep0_queue(struct fsg_common *common)
487 {
488 	int	rc;
489 
490 	rc = usb_ep_queue(common->ep0, common->ep0req, GFP_ATOMIC);
491 	common->ep0->driver_data = common;
492 	if (rc != 0 && rc != -ESHUTDOWN) {
493 		/* We can't do much more than wait for a reset */
494 		WARNING(common, "error in submission: %s --> %d\n",
495 			common->ep0->name, rc);
496 	}
497 	return rc;
498 }
499 
500 /*-------------------------------------------------------------------------*/
501 
502 /* Bulk and interrupt endpoint completion handlers.
503  * These always run in_irq. */
504 
505 static void bulk_in_complete(struct usb_ep *ep, struct usb_request *req)
506 {
507 	struct fsg_common	*common = ep->driver_data;
508 	struct fsg_buffhd	*bh = req->context;
509 
510 	if (req->status || req->actual != req->length)
511 		DBG(common, "%s --> %d, %u/%u\n", __func__,
512 				req->status, req->actual, req->length);
513 	if (req->status == -ECONNRESET)		/* Request was cancelled */
514 		usb_ep_fifo_flush(ep);
515 
516 	/* Hold the lock while we update the request and buffer states */
517 	bh->inreq_busy = 0;
518 	bh->state = BUF_STATE_EMPTY;
519 	wakeup_thread(common);
520 }
521 
522 static void bulk_out_complete(struct usb_ep *ep, struct usb_request *req)
523 {
524 	struct fsg_common	*common = ep->driver_data;
525 	struct fsg_buffhd	*bh = req->context;
526 
527 	dump_msg(common, "bulk-out", req->buf, req->actual);
528 	if (req->status || req->actual != bh->bulk_out_intended_length)
529 		DBG(common, "%s --> %d, %u/%u\n", __func__,
530 				req->status, req->actual,
531 				bh->bulk_out_intended_length);
532 	if (req->status == -ECONNRESET)		/* Request was cancelled */
533 		usb_ep_fifo_flush(ep);
534 
535 	/* Hold the lock while we update the request and buffer states */
536 	bh->outreq_busy = 0;
537 	bh->state = BUF_STATE_FULL;
538 	wakeup_thread(common);
539 }
540 
541 /*-------------------------------------------------------------------------*/
542 
543 /* Ep0 class-specific handlers.  These always run in_irq. */
544 
545 static int fsg_setup(struct usb_function *f,
546 		const struct usb_ctrlrequest *ctrl)
547 {
548 	struct fsg_dev		*fsg = fsg_from_func(f);
549 	struct usb_request	*req = fsg->common->ep0req;
550 	u16			w_index = get_unaligned_le16(&ctrl->wIndex);
551 	u16			w_value = get_unaligned_le16(&ctrl->wValue);
552 	u16			w_length = get_unaligned_le16(&ctrl->wLength);
553 
554 	if (!fsg_is_set(fsg->common))
555 		return -EOPNOTSUPP;
556 
557 	switch (ctrl->bRequest) {
558 
559 	case USB_BULK_RESET_REQUEST:
560 		if (ctrl->bRequestType !=
561 		    (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE))
562 			break;
563 		if (w_index != fsg->interface_number || w_value != 0)
564 			return -EDOM;
565 
566 		/* Raise an exception to stop the current operation
567 		 * and reinitialize our state. */
568 		DBG(fsg, "bulk reset request\n");
569 		raise_exception(fsg->common, FSG_STATE_RESET);
570 		return DELAYED_STATUS;
571 
572 	case USB_BULK_GET_MAX_LUN_REQUEST:
573 		if (ctrl->bRequestType !=
574 		    (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE))
575 			break;
576 		if (w_index != fsg->interface_number || w_value != 0)
577 			return -EDOM;
578 		VDBG(fsg, "get max LUN\n");
579 		*(u8 *) req->buf = fsg->common->nluns - 1;
580 
581 		/* Respond with data/status */
582 		req->length = min((u16)1, w_length);
583 		return ep0_queue(fsg->common);
584 	}
585 
586 	VDBG(fsg,
587 	     "unknown class-specific control req "
588 	     "%02x.%02x v%04x i%04x l%u\n",
589 	     ctrl->bRequestType, ctrl->bRequest,
590 	     get_unaligned_le16(&ctrl->wValue), w_index, w_length);
591 	return -EOPNOTSUPP;
592 }
593 
594 /*-------------------------------------------------------------------------*/
595 
596 /* All the following routines run in process context */
597 
598 /* Use this for bulk or interrupt transfers, not ep0 */
599 static void start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
600 		struct usb_request *req, int *pbusy,
601 		enum fsg_buffer_state *state)
602 {
603 	int	rc;
604 
605 	if (ep == fsg->bulk_in)
606 		dump_msg(fsg, "bulk-in", req->buf, req->length);
607 
608 	*pbusy = 1;
609 	*state = BUF_STATE_BUSY;
610 	rc = usb_ep_queue(ep, req, GFP_KERNEL);
611 	if (rc != 0) {
612 		*pbusy = 0;
613 		*state = BUF_STATE_EMPTY;
614 
615 		/* We can't do much more than wait for a reset */
616 
617 		/* Note: currently the net2280 driver fails zero-length
618 		 * submissions if DMA is enabled. */
619 		if (rc != -ESHUTDOWN && !(rc == -EOPNOTSUPP &&
620 						req->length == 0))
621 			WARNING(fsg, "error in submission: %s --> %d\n",
622 					ep->name, rc);
623 	}
624 }
625 
626 #define START_TRANSFER_OR(common, ep_name, req, pbusy, state)		\
627 	if (fsg_is_set(common))						\
628 		start_transfer((common)->fsg, (common)->fsg->ep_name,	\
629 			       req, pbusy, state);			\
630 	else
631 
632 #define START_TRANSFER(common, ep_name, req, pbusy, state)		\
633 	START_TRANSFER_OR(common, ep_name, req, pbusy, state) (void)0
634 
635 static void busy_indicator(void)
636 {
637 	static int state;
638 
639 	switch (state) {
640 	case 0:
641 		puts("\r|"); break;
642 	case 1:
643 		puts("\r/"); break;
644 	case 2:
645 		puts("\r-"); break;
646 	case 3:
647 		puts("\r\\"); break;
648 	case 4:
649 		puts("\r|"); break;
650 	case 5:
651 		puts("\r/"); break;
652 	case 6:
653 		puts("\r-"); break;
654 	case 7:
655 		puts("\r\\"); break;
656 	default:
657 		state = 0;
658 	}
659 	if (state++ == 8)
660 		state = 0;
661 }
662 
663 static int sleep_thread(struct fsg_common *common)
664 {
665 	int	rc = 0;
666 	int i = 0, k = 0;
667 
668 	/* Wait until a signal arrives or we are woken up */
669 	for (;;) {
670 		if (common->thread_wakeup_needed)
671 			break;
672 
673 		if (++i == 50000) {
674 			busy_indicator();
675 			i = 0;
676 			k++;
677 		}
678 
679 		if (k == 10) {
680 			/* Handle CTRL+C */
681 			if (ctrlc())
682 				return -EPIPE;
683 #ifdef CONFIG_USB_CABLE_CHECK
684 			/* Check cable connection */
685 			if (!usb_cable_connected())
686 				return -EIO;
687 #endif
688 			k = 0;
689 		}
690 
691 		usb_gadget_handle_interrupts();
692 	}
693 	common->thread_wakeup_needed = 0;
694 	return rc;
695 }
696 
697 /*-------------------------------------------------------------------------*/
698 
699 static int do_read(struct fsg_common *common)
700 {
701 	struct fsg_lun		*curlun = &common->luns[common->lun];
702 	u32			lba;
703 	struct fsg_buffhd	*bh;
704 	int			rc;
705 	u32			amount_left;
706 	loff_t			file_offset;
707 	unsigned int		amount;
708 	unsigned int		partial_page;
709 	ssize_t			nread;
710 
711 	/* Get the starting Logical Block Address and check that it's
712 	 * not too big */
713 	if (common->cmnd[0] == SC_READ_6)
714 		lba = get_unaligned_be24(&common->cmnd[1]);
715 	else {
716 		lba = get_unaligned_be32(&common->cmnd[2]);
717 
718 		/* We allow DPO (Disable Page Out = don't save data in the
719 		 * cache) and FUA (Force Unit Access = don't read from the
720 		 * cache), but we don't implement them. */
721 		if ((common->cmnd[1] & ~0x18) != 0) {
722 			curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
723 			return -EINVAL;
724 		}
725 	}
726 	if (lba >= curlun->num_sectors) {
727 		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
728 		return -EINVAL;
729 	}
730 	file_offset = ((loff_t) lba) << 9;
731 
732 	/* Carry out the file reads */
733 	amount_left = common->data_size_from_cmnd;
734 	if (unlikely(amount_left == 0))
735 		return -EIO;		/* No default reply */
736 
737 	for (;;) {
738 
739 		/* Figure out how much we need to read:
740 		 * Try to read the remaining amount.
741 		 * But don't read more than the buffer size.
742 		 * And don't try to read past the end of the file.
743 		 * Finally, if we're not at a page boundary, don't read past
744 		 *	the next page.
745 		 * If this means reading 0 then we were asked to read past
746 		 *	the end of file. */
747 		amount = min(amount_left, FSG_BUFLEN);
748 		partial_page = file_offset & (PAGE_CACHE_SIZE - 1);
749 		if (partial_page > 0)
750 			amount = min(amount, (unsigned int) PAGE_CACHE_SIZE -
751 					partial_page);
752 
753 		/* Wait for the next buffer to become available */
754 		bh = common->next_buffhd_to_fill;
755 		while (bh->state != BUF_STATE_EMPTY) {
756 			rc = sleep_thread(common);
757 			if (rc)
758 				return rc;
759 		}
760 
761 		/* If we were asked to read past the end of file,
762 		 * end with an empty buffer. */
763 		if (amount == 0) {
764 			curlun->sense_data =
765 					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
766 			curlun->info_valid = 1;
767 			bh->inreq->length = 0;
768 			bh->state = BUF_STATE_FULL;
769 			break;
770 		}
771 
772 		/* Perform the read */
773 		rc = ums->read_sector(ums,
774 				      file_offset / SECTOR_SIZE,
775 				      amount / SECTOR_SIZE,
776 				      (char __user *)bh->buf);
777 		if (!rc)
778 			return -EIO;
779 
780 		nread = rc * SECTOR_SIZE;
781 
782 		VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
783 				(unsigned long long) file_offset,
784 				(int) nread);
785 
786 		if (nread < 0) {
787 			LDBG(curlun, "error in file read: %d\n",
788 					(int) nread);
789 			nread = 0;
790 		} else if (nread < amount) {
791 			LDBG(curlun, "partial file read: %d/%u\n",
792 					(int) nread, amount);
793 			nread -= (nread & 511);	/* Round down to a block */
794 		}
795 		file_offset  += nread;
796 		amount_left  -= nread;
797 		common->residue -= nread;
798 		bh->inreq->length = nread;
799 		bh->state = BUF_STATE_FULL;
800 
801 		/* If an error occurred, report it and its position */
802 		if (nread < amount) {
803 			curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
804 			curlun->info_valid = 1;
805 			break;
806 		}
807 
808 		if (amount_left == 0)
809 			break;		/* No more left to read */
810 
811 		/* Send this buffer and go read some more */
812 		bh->inreq->zero = 0;
813 		START_TRANSFER_OR(common, bulk_in, bh->inreq,
814 			       &bh->inreq_busy, &bh->state)
815 			/* Don't know what to do if
816 			 * common->fsg is NULL */
817 			return -EIO;
818 		common->next_buffhd_to_fill = bh->next;
819 	}
820 
821 	return -EIO;		/* No default reply */
822 }
823 
824 /*-------------------------------------------------------------------------*/
825 
826 static int do_write(struct fsg_common *common)
827 {
828 	struct fsg_lun		*curlun = &common->luns[common->lun];
829 	u32			lba;
830 	struct fsg_buffhd	*bh;
831 	int			get_some_more;
832 	u32			amount_left_to_req, amount_left_to_write;
833 	loff_t			usb_offset, file_offset;
834 	unsigned int		amount;
835 	unsigned int		partial_page;
836 	ssize_t			nwritten;
837 	int			rc;
838 
839 	if (curlun->ro) {
840 		curlun->sense_data = SS_WRITE_PROTECTED;
841 		return -EINVAL;
842 	}
843 
844 	/* Get the starting Logical Block Address and check that it's
845 	 * not too big */
846 	if (common->cmnd[0] == SC_WRITE_6)
847 		lba = get_unaligned_be24(&common->cmnd[1]);
848 	else {
849 		lba = get_unaligned_be32(&common->cmnd[2]);
850 
851 		/* We allow DPO (Disable Page Out = don't save data in the
852 		 * cache) and FUA (Force Unit Access = write directly to the
853 		 * medium).  We don't implement DPO; we implement FUA by
854 		 * performing synchronous output. */
855 		if (common->cmnd[1] & ~0x18) {
856 			curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
857 			return -EINVAL;
858 		}
859 	}
860 	if (lba >= curlun->num_sectors) {
861 		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
862 		return -EINVAL;
863 	}
864 
865 	/* Carry out the file writes */
866 	get_some_more = 1;
867 	file_offset = usb_offset = ((loff_t) lba) << 9;
868 	amount_left_to_req = common->data_size_from_cmnd;
869 	amount_left_to_write = common->data_size_from_cmnd;
870 
871 	while (amount_left_to_write > 0) {
872 
873 		/* Queue a request for more data from the host */
874 		bh = common->next_buffhd_to_fill;
875 		if (bh->state == BUF_STATE_EMPTY && get_some_more) {
876 
877 			/* Figure out how much we want to get:
878 			 * Try to get the remaining amount.
879 			 * But don't get more than the buffer size.
880 			 * And don't try to go past the end of the file.
881 			 * If we're not at a page boundary,
882 			 *	don't go past the next page.
883 			 * If this means getting 0, then we were asked
884 			 *	to write past the end of file.
885 			 * Finally, round down to a block boundary. */
886 			amount = min(amount_left_to_req, FSG_BUFLEN);
887 			partial_page = usb_offset & (PAGE_CACHE_SIZE - 1);
888 			if (partial_page > 0)
889 				amount = min(amount,
890 	(unsigned int) PAGE_CACHE_SIZE - partial_page);
891 
892 			if (amount == 0) {
893 				get_some_more = 0;
894 				curlun->sense_data =
895 					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
896 				curlun->info_valid = 1;
897 				continue;
898 			}
899 			amount -= (amount & 511);
900 			if (amount == 0) {
901 
902 				/* Why were we were asked to transfer a
903 				 * partial block? */
904 				get_some_more = 0;
905 				continue;
906 			}
907 
908 			/* Get the next buffer */
909 			usb_offset += amount;
910 			common->usb_amount_left -= amount;
911 			amount_left_to_req -= amount;
912 			if (amount_left_to_req == 0)
913 				get_some_more = 0;
914 
915 			/* amount is always divisible by 512, hence by
916 			 * the bulk-out maxpacket size */
917 			bh->outreq->length = amount;
918 			bh->bulk_out_intended_length = amount;
919 			bh->outreq->short_not_ok = 1;
920 			START_TRANSFER_OR(common, bulk_out, bh->outreq,
921 					  &bh->outreq_busy, &bh->state)
922 				/* Don't know what to do if
923 				 * common->fsg is NULL */
924 				return -EIO;
925 			common->next_buffhd_to_fill = bh->next;
926 			continue;
927 		}
928 
929 		/* Write the received data to the backing file */
930 		bh = common->next_buffhd_to_drain;
931 		if (bh->state == BUF_STATE_EMPTY && !get_some_more)
932 			break;			/* We stopped early */
933 		if (bh->state == BUF_STATE_FULL) {
934 			common->next_buffhd_to_drain = bh->next;
935 			bh->state = BUF_STATE_EMPTY;
936 
937 			/* Did something go wrong with the transfer? */
938 			if (bh->outreq->status != 0) {
939 				curlun->sense_data = SS_COMMUNICATION_FAILURE;
940 				curlun->info_valid = 1;
941 				break;
942 			}
943 
944 			amount = bh->outreq->actual;
945 
946 			/* Perform the write */
947 			rc = ums->write_sector(ums,
948 					       file_offset / SECTOR_SIZE,
949 					       amount / SECTOR_SIZE,
950 					       (char __user *)bh->buf);
951 			if (!rc)
952 				return -EIO;
953 			nwritten = rc * SECTOR_SIZE;
954 
955 			VLDBG(curlun, "file write %u @ %llu -> %d\n", amount,
956 					(unsigned long long) file_offset,
957 					(int) nwritten);
958 
959 			if (nwritten < 0) {
960 				LDBG(curlun, "error in file write: %d\n",
961 						(int) nwritten);
962 				nwritten = 0;
963 			} else if (nwritten < amount) {
964 				LDBG(curlun, "partial file write: %d/%u\n",
965 						(int) nwritten, amount);
966 				nwritten -= (nwritten & 511);
967 				/* Round down to a block */
968 			}
969 			file_offset += nwritten;
970 			amount_left_to_write -= nwritten;
971 			common->residue -= nwritten;
972 
973 			/* If an error occurred, report it and its position */
974 			if (nwritten < amount) {
975 				printf("nwritten:%d amount:%d\n", nwritten,
976 				       amount);
977 				curlun->sense_data = SS_WRITE_ERROR;
978 				curlun->info_valid = 1;
979 				break;
980 			}
981 
982 			/* Did the host decide to stop early? */
983 			if (bh->outreq->actual != bh->outreq->length) {
984 				common->short_packet_received = 1;
985 				break;
986 			}
987 			continue;
988 		}
989 
990 		/* Wait for something to happen */
991 		rc = sleep_thread(common);
992 		if (rc)
993 			return rc;
994 	}
995 
996 	return -EIO;		/* No default reply */
997 }
998 
999 /*-------------------------------------------------------------------------*/
1000 
1001 static int do_synchronize_cache(struct fsg_common *common)
1002 {
1003 	return 0;
1004 }
1005 
1006 /*-------------------------------------------------------------------------*/
1007 
1008 static int do_verify(struct fsg_common *common)
1009 {
1010 	struct fsg_lun		*curlun = &common->luns[common->lun];
1011 	u32			lba;
1012 	u32			verification_length;
1013 	struct fsg_buffhd	*bh = common->next_buffhd_to_fill;
1014 	loff_t			file_offset;
1015 	u32			amount_left;
1016 	unsigned int		amount;
1017 	ssize_t			nread;
1018 	int			rc;
1019 
1020 	/* Get the starting Logical Block Address and check that it's
1021 	 * not too big */
1022 	lba = get_unaligned_be32(&common->cmnd[2]);
1023 	if (lba >= curlun->num_sectors) {
1024 		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1025 		return -EINVAL;
1026 	}
1027 
1028 	/* We allow DPO (Disable Page Out = don't save data in the
1029 	 * cache) but we don't implement it. */
1030 	if (common->cmnd[1] & ~0x10) {
1031 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1032 		return -EINVAL;
1033 	}
1034 
1035 	verification_length = get_unaligned_be16(&common->cmnd[7]);
1036 	if (unlikely(verification_length == 0))
1037 		return -EIO;		/* No default reply */
1038 
1039 	/* Prepare to carry out the file verify */
1040 	amount_left = verification_length << 9;
1041 	file_offset = ((loff_t) lba) << 9;
1042 
1043 	/* Write out all the dirty buffers before invalidating them */
1044 
1045 	/* Just try to read the requested blocks */
1046 	while (amount_left > 0) {
1047 
1048 		/* Figure out how much we need to read:
1049 		 * Try to read the remaining amount, but not more than
1050 		 * the buffer size.
1051 		 * And don't try to read past the end of the file.
1052 		 * If this means reading 0 then we were asked to read
1053 		 * past the end of file. */
1054 		amount = min(amount_left, FSG_BUFLEN);
1055 		if (amount == 0) {
1056 			curlun->sense_data =
1057 					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1058 			curlun->info_valid = 1;
1059 			break;
1060 		}
1061 
1062 		/* Perform the read */
1063 		rc = ums->read_sector(ums,
1064 				      file_offset / SECTOR_SIZE,
1065 				      amount / SECTOR_SIZE,
1066 				      (char __user *)bh->buf);
1067 		if (!rc)
1068 			return -EIO;
1069 		nread = rc * SECTOR_SIZE;
1070 
1071 		VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
1072 				(unsigned long long) file_offset,
1073 				(int) nread);
1074 		if (nread < 0) {
1075 			LDBG(curlun, "error in file verify: %d\n",
1076 					(int) nread);
1077 			nread = 0;
1078 		} else if (nread < amount) {
1079 			LDBG(curlun, "partial file verify: %d/%u\n",
1080 					(int) nread, amount);
1081 			nread -= (nread & 511);	/* Round down to a sector */
1082 		}
1083 		if (nread == 0) {
1084 			curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
1085 			curlun->info_valid = 1;
1086 			break;
1087 		}
1088 		file_offset += nread;
1089 		amount_left -= nread;
1090 	}
1091 	return 0;
1092 }
1093 
1094 /*-------------------------------------------------------------------------*/
1095 
1096 static int do_inquiry(struct fsg_common *common, struct fsg_buffhd *bh)
1097 {
1098 	struct fsg_lun *curlun = &common->luns[common->lun];
1099 	static const char vendor_id[] = "Linux   ";
1100 	u8	*buf = (u8 *) bh->buf;
1101 
1102 	if (!curlun) {		/* Unsupported LUNs are okay */
1103 		common->bad_lun_okay = 1;
1104 		memset(buf, 0, 36);
1105 		buf[0] = 0x7f;		/* Unsupported, no device-type */
1106 		buf[4] = 31;		/* Additional length */
1107 		return 36;
1108 	}
1109 
1110 	memset(buf, 0, 8);
1111 	buf[0] = TYPE_DISK;
1112 	buf[2] = 2;		/* ANSI SCSI level 2 */
1113 	buf[3] = 2;		/* SCSI-2 INQUIRY data format */
1114 	buf[4] = 31;		/* Additional length */
1115 				/* No special options */
1116 	sprintf((char *) (buf + 8), "%-8s%-16s%04x", (char*) vendor_id ,
1117 			ums->name, (u16) 0xffff);
1118 
1119 	return 36;
1120 }
1121 
1122 
1123 static int do_request_sense(struct fsg_common *common, struct fsg_buffhd *bh)
1124 {
1125 	struct fsg_lun	*curlun = &common->luns[common->lun];
1126 	u8		*buf = (u8 *) bh->buf;
1127 	u32		sd, sdinfo;
1128 	int		valid;
1129 
1130 	/*
1131 	 * From the SCSI-2 spec., section 7.9 (Unit attention condition):
1132 	 *
1133 	 * If a REQUEST SENSE command is received from an initiator
1134 	 * with a pending unit attention condition (before the target
1135 	 * generates the contingent allegiance condition), then the
1136 	 * target shall either:
1137 	 *   a) report any pending sense data and preserve the unit
1138 	 *	attention condition on the logical unit, or,
1139 	 *   b) report the unit attention condition, may discard any
1140 	 *	pending sense data, and clear the unit attention
1141 	 *	condition on the logical unit for that initiator.
1142 	 *
1143 	 * FSG normally uses option a); enable this code to use option b).
1144 	 */
1145 #if 0
1146 	if (curlun && curlun->unit_attention_data != SS_NO_SENSE) {
1147 		curlun->sense_data = curlun->unit_attention_data;
1148 		curlun->unit_attention_data = SS_NO_SENSE;
1149 	}
1150 #endif
1151 
1152 	if (!curlun) {		/* Unsupported LUNs are okay */
1153 		common->bad_lun_okay = 1;
1154 		sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
1155 		sdinfo = 0;
1156 		valid = 0;
1157 	} else {
1158 		sd = curlun->sense_data;
1159 		valid = curlun->info_valid << 7;
1160 		curlun->sense_data = SS_NO_SENSE;
1161 		curlun->info_valid = 0;
1162 	}
1163 
1164 	memset(buf, 0, 18);
1165 	buf[0] = valid | 0x70;			/* Valid, current error */
1166 	buf[2] = SK(sd);
1167 	put_unaligned_be32(sdinfo, &buf[3]);	/* Sense information */
1168 	buf[7] = 18 - 8;			/* Additional sense length */
1169 	buf[12] = ASC(sd);
1170 	buf[13] = ASCQ(sd);
1171 	return 18;
1172 }
1173 
1174 static int do_read_capacity(struct fsg_common *common, struct fsg_buffhd *bh)
1175 {
1176 	struct fsg_lun	*curlun = &common->luns[common->lun];
1177 	u32		lba = get_unaligned_be32(&common->cmnd[2]);
1178 	int		pmi = common->cmnd[8];
1179 	u8		*buf = (u8 *) bh->buf;
1180 
1181 	/* Check the PMI and LBA fields */
1182 	if (pmi > 1 || (pmi == 0 && lba != 0)) {
1183 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1184 		return -EINVAL;
1185 	}
1186 
1187 	put_unaligned_be32(curlun->num_sectors - 1, &buf[0]);
1188 						/* Max logical block */
1189 	put_unaligned_be32(512, &buf[4]);	/* Block length */
1190 	return 8;
1191 }
1192 
1193 static int do_read_header(struct fsg_common *common, struct fsg_buffhd *bh)
1194 {
1195 	struct fsg_lun	*curlun = &common->luns[common->lun];
1196 	int		msf = common->cmnd[1] & 0x02;
1197 	u32		lba = get_unaligned_be32(&common->cmnd[2]);
1198 	u8		*buf = (u8 *) bh->buf;
1199 
1200 	if (common->cmnd[1] & ~0x02) {		/* Mask away MSF */
1201 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1202 		return -EINVAL;
1203 	}
1204 	if (lba >= curlun->num_sectors) {
1205 		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1206 		return -EINVAL;
1207 	}
1208 
1209 	memset(buf, 0, 8);
1210 	buf[0] = 0x01;		/* 2048 bytes of user data, rest is EC */
1211 	store_cdrom_address(&buf[4], msf, lba);
1212 	return 8;
1213 }
1214 
1215 
1216 static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
1217 {
1218 	struct fsg_lun	*curlun = &common->luns[common->lun];
1219 	int		msf = common->cmnd[1] & 0x02;
1220 	int		start_track = common->cmnd[6];
1221 	u8		*buf = (u8 *) bh->buf;
1222 
1223 	if ((common->cmnd[1] & ~0x02) != 0 ||	/* Mask away MSF */
1224 			start_track > 1) {
1225 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1226 		return -EINVAL;
1227 	}
1228 
1229 	memset(buf, 0, 20);
1230 	buf[1] = (20-2);		/* TOC data length */
1231 	buf[2] = 1;			/* First track number */
1232 	buf[3] = 1;			/* Last track number */
1233 	buf[5] = 0x16;			/* Data track, copying allowed */
1234 	buf[6] = 0x01;			/* Only track is number 1 */
1235 	store_cdrom_address(&buf[8], msf, 0);
1236 
1237 	buf[13] = 0x16;			/* Lead-out track is data */
1238 	buf[14] = 0xAA;			/* Lead-out track number */
1239 	store_cdrom_address(&buf[16], msf, curlun->num_sectors);
1240 
1241 	return 20;
1242 }
1243 
1244 static int do_mode_sense(struct fsg_common *common, struct fsg_buffhd *bh)
1245 {
1246 	struct fsg_lun	*curlun = &common->luns[common->lun];
1247 	int		mscmnd = common->cmnd[0];
1248 	u8		*buf = (u8 *) bh->buf;
1249 	u8		*buf0 = buf;
1250 	int		pc, page_code;
1251 	int		changeable_values, all_pages;
1252 	int		valid_page = 0;
1253 	int		len, limit;
1254 
1255 	if ((common->cmnd[1] & ~0x08) != 0) {	/* Mask away DBD */
1256 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1257 		return -EINVAL;
1258 	}
1259 	pc = common->cmnd[2] >> 6;
1260 	page_code = common->cmnd[2] & 0x3f;
1261 	if (pc == 3) {
1262 		curlun->sense_data = SS_SAVING_PARAMETERS_NOT_SUPPORTED;
1263 		return -EINVAL;
1264 	}
1265 	changeable_values = (pc == 1);
1266 	all_pages = (page_code == 0x3f);
1267 
1268 	/* Write the mode parameter header.  Fixed values are: default
1269 	 * medium type, no cache control (DPOFUA), and no block descriptors.
1270 	 * The only variable value is the WriteProtect bit.  We will fill in
1271 	 * the mode data length later. */
1272 	memset(buf, 0, 8);
1273 	if (mscmnd == SC_MODE_SENSE_6) {
1274 		buf[2] = (curlun->ro ? 0x80 : 0x00);		/* WP, DPOFUA */
1275 		buf += 4;
1276 		limit = 255;
1277 	} else {			/* SC_MODE_SENSE_10 */
1278 		buf[3] = (curlun->ro ? 0x80 : 0x00);		/* WP, DPOFUA */
1279 		buf += 8;
1280 		limit = 65535;		/* Should really be FSG_BUFLEN */
1281 	}
1282 
1283 	/* No block descriptors */
1284 
1285 	/* The mode pages, in numerical order.  The only page we support
1286 	 * is the Caching page. */
1287 	if (page_code == 0x08 || all_pages) {
1288 		valid_page = 1;
1289 		buf[0] = 0x08;		/* Page code */
1290 		buf[1] = 10;		/* Page length */
1291 		memset(buf+2, 0, 10);	/* None of the fields are changeable */
1292 
1293 		if (!changeable_values) {
1294 			buf[2] = 0x04;	/* Write cache enable, */
1295 					/* Read cache not disabled */
1296 					/* No cache retention priorities */
1297 			put_unaligned_be16(0xffff, &buf[4]);
1298 					/* Don't disable prefetch */
1299 					/* Minimum prefetch = 0 */
1300 			put_unaligned_be16(0xffff, &buf[8]);
1301 					/* Maximum prefetch */
1302 			put_unaligned_be16(0xffff, &buf[10]);
1303 					/* Maximum prefetch ceiling */
1304 		}
1305 		buf += 12;
1306 	}
1307 
1308 	/* Check that a valid page was requested and the mode data length
1309 	 * isn't too long. */
1310 	len = buf - buf0;
1311 	if (!valid_page || len > limit) {
1312 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1313 		return -EINVAL;
1314 	}
1315 
1316 	/*  Store the mode data length */
1317 	if (mscmnd == SC_MODE_SENSE_6)
1318 		buf0[0] = len - 1;
1319 	else
1320 		put_unaligned_be16(len - 2, buf0);
1321 	return len;
1322 }
1323 
1324 
1325 static int do_start_stop(struct fsg_common *common)
1326 {
1327 	struct fsg_lun	*curlun = &common->luns[common->lun];
1328 
1329 	if (!curlun) {
1330 		return -EINVAL;
1331 	} else if (!curlun->removable) {
1332 		curlun->sense_data = SS_INVALID_COMMAND;
1333 		return -EINVAL;
1334 	}
1335 
1336 	return 0;
1337 }
1338 
1339 static int do_prevent_allow(struct fsg_common *common)
1340 {
1341 	struct fsg_lun	*curlun = &common->luns[common->lun];
1342 	int		prevent;
1343 
1344 	if (!curlun->removable) {
1345 		curlun->sense_data = SS_INVALID_COMMAND;
1346 		return -EINVAL;
1347 	}
1348 
1349 	prevent = common->cmnd[4] & 0x01;
1350 	if ((common->cmnd[4] & ~0x01) != 0) {	/* Mask away Prevent */
1351 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1352 		return -EINVAL;
1353 	}
1354 
1355 	if (curlun->prevent_medium_removal && !prevent)
1356 		fsg_lun_fsync_sub(curlun);
1357 	curlun->prevent_medium_removal = prevent;
1358 	return 0;
1359 }
1360 
1361 
1362 static int do_read_format_capacities(struct fsg_common *common,
1363 			struct fsg_buffhd *bh)
1364 {
1365 	struct fsg_lun	*curlun = &common->luns[common->lun];
1366 	u8		*buf = (u8 *) bh->buf;
1367 
1368 	buf[0] = buf[1] = buf[2] = 0;
1369 	buf[3] = 8;	/* Only the Current/Maximum Capacity Descriptor */
1370 	buf += 4;
1371 
1372 	put_unaligned_be32(curlun->num_sectors, &buf[0]);
1373 						/* Number of blocks */
1374 	put_unaligned_be32(512, &buf[4]);	/* Block length */
1375 	buf[4] = 0x02;				/* Current capacity */
1376 	return 12;
1377 }
1378 
1379 
1380 static int do_mode_select(struct fsg_common *common, struct fsg_buffhd *bh)
1381 {
1382 	struct fsg_lun	*curlun = &common->luns[common->lun];
1383 
1384 	/* We don't support MODE SELECT */
1385 	if (curlun)
1386 		curlun->sense_data = SS_INVALID_COMMAND;
1387 	return -EINVAL;
1388 }
1389 
1390 
1391 /*-------------------------------------------------------------------------*/
1392 
1393 static int halt_bulk_in_endpoint(struct fsg_dev *fsg)
1394 {
1395 	int	rc;
1396 
1397 	rc = fsg_set_halt(fsg, fsg->bulk_in);
1398 	if (rc == -EAGAIN)
1399 		VDBG(fsg, "delayed bulk-in endpoint halt\n");
1400 	while (rc != 0) {
1401 		if (rc != -EAGAIN) {
1402 			WARNING(fsg, "usb_ep_set_halt -> %d\n", rc);
1403 			rc = 0;
1404 			break;
1405 		}
1406 
1407 		rc = usb_ep_set_halt(fsg->bulk_in);
1408 	}
1409 	return rc;
1410 }
1411 
1412 static int wedge_bulk_in_endpoint(struct fsg_dev *fsg)
1413 {
1414 	int	rc;
1415 
1416 	DBG(fsg, "bulk-in set wedge\n");
1417 	rc = 0; /* usb_ep_set_wedge(fsg->bulk_in); */
1418 	if (rc == -EAGAIN)
1419 		VDBG(fsg, "delayed bulk-in endpoint wedge\n");
1420 	while (rc != 0) {
1421 		if (rc != -EAGAIN) {
1422 			WARNING(fsg, "usb_ep_set_wedge -> %d\n", rc);
1423 			rc = 0;
1424 			break;
1425 		}
1426 	}
1427 	return rc;
1428 }
1429 
1430 static int pad_with_zeros(struct fsg_dev *fsg)
1431 {
1432 	struct fsg_buffhd	*bh = fsg->common->next_buffhd_to_fill;
1433 	u32			nkeep = bh->inreq->length;
1434 	u32			nsend;
1435 	int			rc;
1436 
1437 	bh->state = BUF_STATE_EMPTY;		/* For the first iteration */
1438 	fsg->common->usb_amount_left = nkeep + fsg->common->residue;
1439 	while (fsg->common->usb_amount_left > 0) {
1440 
1441 		/* Wait for the next buffer to be free */
1442 		while (bh->state != BUF_STATE_EMPTY) {
1443 			rc = sleep_thread(fsg->common);
1444 			if (rc)
1445 				return rc;
1446 		}
1447 
1448 		nsend = min(fsg->common->usb_amount_left, FSG_BUFLEN);
1449 		memset(bh->buf + nkeep, 0, nsend - nkeep);
1450 		bh->inreq->length = nsend;
1451 		bh->inreq->zero = 0;
1452 		start_transfer(fsg, fsg->bulk_in, bh->inreq,
1453 				&bh->inreq_busy, &bh->state);
1454 		bh = fsg->common->next_buffhd_to_fill = bh->next;
1455 		fsg->common->usb_amount_left -= nsend;
1456 		nkeep = 0;
1457 	}
1458 	return 0;
1459 }
1460 
1461 static int throw_away_data(struct fsg_common *common)
1462 {
1463 	struct fsg_buffhd	*bh;
1464 	u32			amount;
1465 	int			rc;
1466 
1467 	for (bh = common->next_buffhd_to_drain;
1468 	     bh->state != BUF_STATE_EMPTY || common->usb_amount_left > 0;
1469 	     bh = common->next_buffhd_to_drain) {
1470 
1471 		/* Throw away the data in a filled buffer */
1472 		if (bh->state == BUF_STATE_FULL) {
1473 			bh->state = BUF_STATE_EMPTY;
1474 			common->next_buffhd_to_drain = bh->next;
1475 
1476 			/* A short packet or an error ends everything */
1477 			if (bh->outreq->actual != bh->outreq->length ||
1478 					bh->outreq->status != 0) {
1479 				raise_exception(common,
1480 						FSG_STATE_ABORT_BULK_OUT);
1481 				return -EINTR;
1482 			}
1483 			continue;
1484 		}
1485 
1486 		/* Try to submit another request if we need one */
1487 		bh = common->next_buffhd_to_fill;
1488 		if (bh->state == BUF_STATE_EMPTY
1489 		 && common->usb_amount_left > 0) {
1490 			amount = min(common->usb_amount_left, FSG_BUFLEN);
1491 
1492 			/* amount is always divisible by 512, hence by
1493 			 * the bulk-out maxpacket size */
1494 			bh->outreq->length = amount;
1495 			bh->bulk_out_intended_length = amount;
1496 			bh->outreq->short_not_ok = 1;
1497 			START_TRANSFER_OR(common, bulk_out, bh->outreq,
1498 					  &bh->outreq_busy, &bh->state)
1499 				/* Don't know what to do if
1500 				 * common->fsg is NULL */
1501 				return -EIO;
1502 			common->next_buffhd_to_fill = bh->next;
1503 			common->usb_amount_left -= amount;
1504 			continue;
1505 		}
1506 
1507 		/* Otherwise wait for something to happen */
1508 		rc = sleep_thread(common);
1509 		if (rc)
1510 			return rc;
1511 	}
1512 	return 0;
1513 }
1514 
1515 
1516 static int finish_reply(struct fsg_common *common)
1517 {
1518 	struct fsg_buffhd	*bh = common->next_buffhd_to_fill;
1519 	int			rc = 0;
1520 
1521 	switch (common->data_dir) {
1522 	case DATA_DIR_NONE:
1523 		break;			/* Nothing to send */
1524 
1525 	/* If we don't know whether the host wants to read or write,
1526 	 * this must be CB or CBI with an unknown command.  We mustn't
1527 	 * try to send or receive any data.  So stall both bulk pipes
1528 	 * if we can and wait for a reset. */
1529 	case DATA_DIR_UNKNOWN:
1530 		if (!common->can_stall) {
1531 			/* Nothing */
1532 		} else if (fsg_is_set(common)) {
1533 			fsg_set_halt(common->fsg, common->fsg->bulk_out);
1534 			rc = halt_bulk_in_endpoint(common->fsg);
1535 		} else {
1536 			/* Don't know what to do if common->fsg is NULL */
1537 			rc = -EIO;
1538 		}
1539 		break;
1540 
1541 	/* All but the last buffer of data must have already been sent */
1542 	case DATA_DIR_TO_HOST:
1543 		if (common->data_size == 0) {
1544 			/* Nothing to send */
1545 
1546 		/* If there's no residue, simply send the last buffer */
1547 		} else if (common->residue == 0) {
1548 			bh->inreq->zero = 0;
1549 			START_TRANSFER_OR(common, bulk_in, bh->inreq,
1550 					  &bh->inreq_busy, &bh->state)
1551 				return -EIO;
1552 			common->next_buffhd_to_fill = bh->next;
1553 
1554 		/* For Bulk-only, if we're allowed to stall then send the
1555 		 * short packet and halt the bulk-in endpoint.  If we can't
1556 		 * stall, pad out the remaining data with 0's. */
1557 		} else if (common->can_stall) {
1558 			bh->inreq->zero = 1;
1559 			START_TRANSFER_OR(common, bulk_in, bh->inreq,
1560 					  &bh->inreq_busy, &bh->state)
1561 				/* Don't know what to do if
1562 				 * common->fsg is NULL */
1563 				rc = -EIO;
1564 			common->next_buffhd_to_fill = bh->next;
1565 			if (common->fsg)
1566 				rc = halt_bulk_in_endpoint(common->fsg);
1567 		} else if (fsg_is_set(common)) {
1568 			rc = pad_with_zeros(common->fsg);
1569 		} else {
1570 			/* Don't know what to do if common->fsg is NULL */
1571 			rc = -EIO;
1572 		}
1573 		break;
1574 
1575 	/* We have processed all we want from the data the host has sent.
1576 	 * There may still be outstanding bulk-out requests. */
1577 	case DATA_DIR_FROM_HOST:
1578 		if (common->residue == 0) {
1579 			/* Nothing to receive */
1580 
1581 		/* Did the host stop sending unexpectedly early? */
1582 		} else if (common->short_packet_received) {
1583 			raise_exception(common, FSG_STATE_ABORT_BULK_OUT);
1584 			rc = -EINTR;
1585 
1586 		/* We haven't processed all the incoming data.  Even though
1587 		 * we may be allowed to stall, doing so would cause a race.
1588 		 * The controller may already have ACK'ed all the remaining
1589 		 * bulk-out packets, in which case the host wouldn't see a
1590 		 * STALL.  Not realizing the endpoint was halted, it wouldn't
1591 		 * clear the halt -- leading to problems later on. */
1592 #if 0
1593 		} else if (common->can_stall) {
1594 			if (fsg_is_set(common))
1595 				fsg_set_halt(common->fsg,
1596 					     common->fsg->bulk_out);
1597 			raise_exception(common, FSG_STATE_ABORT_BULK_OUT);
1598 			rc = -EINTR;
1599 #endif
1600 
1601 		/* We can't stall.  Read in the excess data and throw it
1602 		 * all away. */
1603 		} else {
1604 			rc = throw_away_data(common);
1605 		}
1606 		break;
1607 	}
1608 	return rc;
1609 }
1610 
1611 
1612 static int send_status(struct fsg_common *common)
1613 {
1614 	struct fsg_lun		*curlun = &common->luns[common->lun];
1615 	struct fsg_buffhd	*bh;
1616 	struct bulk_cs_wrap	*csw;
1617 	int			rc;
1618 	u8			status = USB_STATUS_PASS;
1619 	u32			sd, sdinfo = 0;
1620 
1621 	/* Wait for the next buffer to become available */
1622 	bh = common->next_buffhd_to_fill;
1623 	while (bh->state != BUF_STATE_EMPTY) {
1624 		rc = sleep_thread(common);
1625 		if (rc)
1626 			return rc;
1627 	}
1628 
1629 	if (curlun)
1630 		sd = curlun->sense_data;
1631 	else if (common->bad_lun_okay)
1632 		sd = SS_NO_SENSE;
1633 	else
1634 		sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
1635 
1636 	if (common->phase_error) {
1637 		DBG(common, "sending phase-error status\n");
1638 		status = USB_STATUS_PHASE_ERROR;
1639 		sd = SS_INVALID_COMMAND;
1640 	} else if (sd != SS_NO_SENSE) {
1641 		DBG(common, "sending command-failure status\n");
1642 		status = USB_STATUS_FAIL;
1643 		VDBG(common, "  sense data: SK x%02x, ASC x%02x, ASCQ x%02x;"
1644 			"  info x%x\n",
1645 			SK(sd), ASC(sd), ASCQ(sd), sdinfo);
1646 	}
1647 
1648 	/* Store and send the Bulk-only CSW */
1649 	csw = (void *)bh->buf;
1650 
1651 	csw->Signature = cpu_to_le32(USB_BULK_CS_SIG);
1652 	csw->Tag = common->tag;
1653 	csw->Residue = cpu_to_le32(common->residue);
1654 	csw->Status = status;
1655 
1656 	bh->inreq->length = USB_BULK_CS_WRAP_LEN;
1657 	bh->inreq->zero = 0;
1658 	START_TRANSFER_OR(common, bulk_in, bh->inreq,
1659 			  &bh->inreq_busy, &bh->state)
1660 		/* Don't know what to do if common->fsg is NULL */
1661 		return -EIO;
1662 
1663 	common->next_buffhd_to_fill = bh->next;
1664 	return 0;
1665 }
1666 
1667 
1668 /*-------------------------------------------------------------------------*/
1669 
1670 /* Check whether the command is properly formed and whether its data size
1671  * and direction agree with the values we already have. */
1672 static int check_command(struct fsg_common *common, int cmnd_size,
1673 		enum data_direction data_dir, unsigned int mask,
1674 		int needs_medium, const char *name)
1675 {
1676 	int			i;
1677 	int			lun = common->cmnd[1] >> 5;
1678 	static const char	dirletter[4] = {'u', 'o', 'i', 'n'};
1679 	char			hdlen[20];
1680 	struct fsg_lun		*curlun;
1681 
1682 	hdlen[0] = 0;
1683 	if (common->data_dir != DATA_DIR_UNKNOWN)
1684 		sprintf(hdlen, ", H%c=%u", dirletter[(int) common->data_dir],
1685 				common->data_size);
1686 	VDBG(common, "SCSI command: %s;  Dc=%d, D%c=%u;  Hc=%d%s\n",
1687 	     name, cmnd_size, dirletter[(int) data_dir],
1688 	     common->data_size_from_cmnd, common->cmnd_size, hdlen);
1689 
1690 	/* We can't reply at all until we know the correct data direction
1691 	 * and size. */
1692 	if (common->data_size_from_cmnd == 0)
1693 		data_dir = DATA_DIR_NONE;
1694 	if (common->data_size < common->data_size_from_cmnd) {
1695 		/* Host data size < Device data size is a phase error.
1696 		 * Carry out the command, but only transfer as much as
1697 		 * we are allowed. */
1698 		common->data_size_from_cmnd = common->data_size;
1699 		common->phase_error = 1;
1700 	}
1701 	common->residue = common->data_size;
1702 	common->usb_amount_left = common->data_size;
1703 
1704 	/* Conflicting data directions is a phase error */
1705 	if (common->data_dir != data_dir
1706 	 && common->data_size_from_cmnd > 0) {
1707 		common->phase_error = 1;
1708 		return -EINVAL;
1709 	}
1710 
1711 	/* Verify the length of the command itself */
1712 	if (cmnd_size != common->cmnd_size) {
1713 
1714 		/* Special case workaround: There are plenty of buggy SCSI
1715 		 * implementations. Many have issues with cbw->Length
1716 		 * field passing a wrong command size. For those cases we
1717 		 * always try to work around the problem by using the length
1718 		 * sent by the host side provided it is at least as large
1719 		 * as the correct command length.
1720 		 * Examples of such cases would be MS-Windows, which issues
1721 		 * REQUEST SENSE with cbw->Length == 12 where it should
1722 		 * be 6, and xbox360 issuing INQUIRY, TEST UNIT READY and
1723 		 * REQUEST SENSE with cbw->Length == 10 where it should
1724 		 * be 6 as well.
1725 		 */
1726 		if (cmnd_size <= common->cmnd_size) {
1727 			DBG(common, "%s is buggy! Expected length %d "
1728 			    "but we got %d\n", name,
1729 			    cmnd_size, common->cmnd_size);
1730 			cmnd_size = common->cmnd_size;
1731 		} else {
1732 			common->phase_error = 1;
1733 			return -EINVAL;
1734 		}
1735 	}
1736 
1737 	/* Check that the LUN values are consistent */
1738 	if (common->lun != lun)
1739 		DBG(common, "using LUN %d from CBW, not LUN %d from CDB\n",
1740 		    common->lun, lun);
1741 
1742 	/* Check the LUN */
1743 	if (common->lun >= 0 && common->lun < common->nluns) {
1744 		curlun = &common->luns[common->lun];
1745 		if (common->cmnd[0] != SC_REQUEST_SENSE) {
1746 			curlun->sense_data = SS_NO_SENSE;
1747 			curlun->info_valid = 0;
1748 		}
1749 	} else {
1750 		curlun = NULL;
1751 		common->bad_lun_okay = 0;
1752 
1753 		/* INQUIRY and REQUEST SENSE commands are explicitly allowed
1754 		 * to use unsupported LUNs; all others may not. */
1755 		if (common->cmnd[0] != SC_INQUIRY &&
1756 		    common->cmnd[0] != SC_REQUEST_SENSE) {
1757 			DBG(common, "unsupported LUN %d\n", common->lun);
1758 			return -EINVAL;
1759 		}
1760 	}
1761 #if 0
1762 	/* If a unit attention condition exists, only INQUIRY and
1763 	 * REQUEST SENSE commands are allowed; anything else must fail. */
1764 	if (curlun && curlun->unit_attention_data != SS_NO_SENSE &&
1765 			common->cmnd[0] != SC_INQUIRY &&
1766 			common->cmnd[0] != SC_REQUEST_SENSE) {
1767 		curlun->sense_data = curlun->unit_attention_data;
1768 		curlun->unit_attention_data = SS_NO_SENSE;
1769 		return -EINVAL;
1770 	}
1771 #endif
1772 	/* Check that only command bytes listed in the mask are non-zero */
1773 	common->cmnd[1] &= 0x1f;			/* Mask away the LUN */
1774 	for (i = 1; i < cmnd_size; ++i) {
1775 		if (common->cmnd[i] && !(mask & (1 << i))) {
1776 			if (curlun)
1777 				curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1778 			return -EINVAL;
1779 		}
1780 	}
1781 
1782 	return 0;
1783 }
1784 
1785 
1786 static int do_scsi_command(struct fsg_common *common)
1787 {
1788 	struct fsg_buffhd	*bh;
1789 	int			rc;
1790 	int			reply = -EINVAL;
1791 	int			i;
1792 	static char		unknown[16];
1793 	struct fsg_lun		*curlun = &common->luns[common->lun];
1794 
1795 	dump_cdb(common);
1796 
1797 	/* Wait for the next buffer to become available for data or status */
1798 	bh = common->next_buffhd_to_fill;
1799 	common->next_buffhd_to_drain = bh;
1800 	while (bh->state != BUF_STATE_EMPTY) {
1801 		rc = sleep_thread(common);
1802 		if (rc)
1803 			return rc;
1804 	}
1805 	common->phase_error = 0;
1806 	common->short_packet_received = 0;
1807 
1808 	down_read(&common->filesem);	/* We're using the backing file */
1809 	switch (common->cmnd[0]) {
1810 
1811 	case SC_INQUIRY:
1812 		common->data_size_from_cmnd = common->cmnd[4];
1813 		reply = check_command(common, 6, DATA_DIR_TO_HOST,
1814 				      (1<<4), 0,
1815 				      "INQUIRY");
1816 		if (reply == 0)
1817 			reply = do_inquiry(common, bh);
1818 		break;
1819 
1820 	case SC_MODE_SELECT_6:
1821 		common->data_size_from_cmnd = common->cmnd[4];
1822 		reply = check_command(common, 6, DATA_DIR_FROM_HOST,
1823 				      (1<<1) | (1<<4), 0,
1824 				      "MODE SELECT(6)");
1825 		if (reply == 0)
1826 			reply = do_mode_select(common, bh);
1827 		break;
1828 
1829 	case SC_MODE_SELECT_10:
1830 		common->data_size_from_cmnd =
1831 			get_unaligned_be16(&common->cmnd[7]);
1832 		reply = check_command(common, 10, DATA_DIR_FROM_HOST,
1833 				      (1<<1) | (3<<7), 0,
1834 				      "MODE SELECT(10)");
1835 		if (reply == 0)
1836 			reply = do_mode_select(common, bh);
1837 		break;
1838 
1839 	case SC_MODE_SENSE_6:
1840 		common->data_size_from_cmnd = common->cmnd[4];
1841 		reply = check_command(common, 6, DATA_DIR_TO_HOST,
1842 				      (1<<1) | (1<<2) | (1<<4), 0,
1843 				      "MODE SENSE(6)");
1844 		if (reply == 0)
1845 			reply = do_mode_sense(common, bh);
1846 		break;
1847 
1848 	case SC_MODE_SENSE_10:
1849 		common->data_size_from_cmnd =
1850 			get_unaligned_be16(&common->cmnd[7]);
1851 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1852 				      (1<<1) | (1<<2) | (3<<7), 0,
1853 				      "MODE SENSE(10)");
1854 		if (reply == 0)
1855 			reply = do_mode_sense(common, bh);
1856 		break;
1857 
1858 	case SC_PREVENT_ALLOW_MEDIUM_REMOVAL:
1859 		common->data_size_from_cmnd = 0;
1860 		reply = check_command(common, 6, DATA_DIR_NONE,
1861 				      (1<<4), 0,
1862 				      "PREVENT-ALLOW MEDIUM REMOVAL");
1863 		if (reply == 0)
1864 			reply = do_prevent_allow(common);
1865 		break;
1866 
1867 	case SC_READ_6:
1868 		i = common->cmnd[4];
1869 		common->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
1870 		reply = check_command(common, 6, DATA_DIR_TO_HOST,
1871 				      (7<<1) | (1<<4), 1,
1872 				      "READ(6)");
1873 		if (reply == 0)
1874 			reply = do_read(common);
1875 		break;
1876 
1877 	case SC_READ_10:
1878 		common->data_size_from_cmnd =
1879 				get_unaligned_be16(&common->cmnd[7]) << 9;
1880 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1881 				      (1<<1) | (0xf<<2) | (3<<7), 1,
1882 				      "READ(10)");
1883 		if (reply == 0)
1884 			reply = do_read(common);
1885 		break;
1886 
1887 	case SC_READ_12:
1888 		common->data_size_from_cmnd =
1889 				get_unaligned_be32(&common->cmnd[6]) << 9;
1890 		reply = check_command(common, 12, DATA_DIR_TO_HOST,
1891 				      (1<<1) | (0xf<<2) | (0xf<<6), 1,
1892 				      "READ(12)");
1893 		if (reply == 0)
1894 			reply = do_read(common);
1895 		break;
1896 
1897 	case SC_READ_CAPACITY:
1898 		common->data_size_from_cmnd = 8;
1899 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1900 				      (0xf<<2) | (1<<8), 1,
1901 				      "READ CAPACITY");
1902 		if (reply == 0)
1903 			reply = do_read_capacity(common, bh);
1904 		break;
1905 
1906 	case SC_READ_HEADER:
1907 		if (!common->luns[common->lun].cdrom)
1908 			goto unknown_cmnd;
1909 		common->data_size_from_cmnd =
1910 			get_unaligned_be16(&common->cmnd[7]);
1911 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1912 				      (3<<7) | (0x1f<<1), 1,
1913 				      "READ HEADER");
1914 		if (reply == 0)
1915 			reply = do_read_header(common, bh);
1916 		break;
1917 
1918 	case SC_READ_TOC:
1919 		if (!common->luns[common->lun].cdrom)
1920 			goto unknown_cmnd;
1921 		common->data_size_from_cmnd =
1922 			get_unaligned_be16(&common->cmnd[7]);
1923 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1924 				      (7<<6) | (1<<1), 1,
1925 				      "READ TOC");
1926 		if (reply == 0)
1927 			reply = do_read_toc(common, bh);
1928 		break;
1929 
1930 	case SC_READ_FORMAT_CAPACITIES:
1931 		common->data_size_from_cmnd =
1932 			get_unaligned_be16(&common->cmnd[7]);
1933 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1934 				      (3<<7), 1,
1935 				      "READ FORMAT CAPACITIES");
1936 		if (reply == 0)
1937 			reply = do_read_format_capacities(common, bh);
1938 		break;
1939 
1940 	case SC_REQUEST_SENSE:
1941 		common->data_size_from_cmnd = common->cmnd[4];
1942 		reply = check_command(common, 6, DATA_DIR_TO_HOST,
1943 				      (1<<4), 0,
1944 				      "REQUEST SENSE");
1945 		if (reply == 0)
1946 			reply = do_request_sense(common, bh);
1947 		break;
1948 
1949 	case SC_START_STOP_UNIT:
1950 		common->data_size_from_cmnd = 0;
1951 		reply = check_command(common, 6, DATA_DIR_NONE,
1952 				      (1<<1) | (1<<4), 0,
1953 				      "START-STOP UNIT");
1954 		if (reply == 0)
1955 			reply = do_start_stop(common);
1956 		break;
1957 
1958 	case SC_SYNCHRONIZE_CACHE:
1959 		common->data_size_from_cmnd = 0;
1960 		reply = check_command(common, 10, DATA_DIR_NONE,
1961 				      (0xf<<2) | (3<<7), 1,
1962 				      "SYNCHRONIZE CACHE");
1963 		if (reply == 0)
1964 			reply = do_synchronize_cache(common);
1965 		break;
1966 
1967 	case SC_TEST_UNIT_READY:
1968 		common->data_size_from_cmnd = 0;
1969 		reply = check_command(common, 6, DATA_DIR_NONE,
1970 				0, 1,
1971 				"TEST UNIT READY");
1972 		break;
1973 
1974 	/* Although optional, this command is used by MS-Windows.  We
1975 	 * support a minimal version: BytChk must be 0. */
1976 	case SC_VERIFY:
1977 		common->data_size_from_cmnd = 0;
1978 		reply = check_command(common, 10, DATA_DIR_NONE,
1979 				      (1<<1) | (0xf<<2) | (3<<7), 1,
1980 				      "VERIFY");
1981 		if (reply == 0)
1982 			reply = do_verify(common);
1983 		break;
1984 
1985 	case SC_WRITE_6:
1986 		i = common->cmnd[4];
1987 		common->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
1988 		reply = check_command(common, 6, DATA_DIR_FROM_HOST,
1989 				      (7<<1) | (1<<4), 1,
1990 				      "WRITE(6)");
1991 		if (reply == 0)
1992 			reply = do_write(common);
1993 		break;
1994 
1995 	case SC_WRITE_10:
1996 		common->data_size_from_cmnd =
1997 				get_unaligned_be16(&common->cmnd[7]) << 9;
1998 		reply = check_command(common, 10, DATA_DIR_FROM_HOST,
1999 				      (1<<1) | (0xf<<2) | (3<<7), 1,
2000 				      "WRITE(10)");
2001 		if (reply == 0)
2002 			reply = do_write(common);
2003 		break;
2004 
2005 	case SC_WRITE_12:
2006 		common->data_size_from_cmnd =
2007 				get_unaligned_be32(&common->cmnd[6]) << 9;
2008 		reply = check_command(common, 12, DATA_DIR_FROM_HOST,
2009 				      (1<<1) | (0xf<<2) | (0xf<<6), 1,
2010 				      "WRITE(12)");
2011 		if (reply == 0)
2012 			reply = do_write(common);
2013 		break;
2014 
2015 	/* Some mandatory commands that we recognize but don't implement.
2016 	 * They don't mean much in this setting.  It's left as an exercise
2017 	 * for anyone interested to implement RESERVE and RELEASE in terms
2018 	 * of Posix locks. */
2019 	case SC_FORMAT_UNIT:
2020 	case SC_RELEASE:
2021 	case SC_RESERVE:
2022 	case SC_SEND_DIAGNOSTIC:
2023 		/* Fall through */
2024 
2025 	default:
2026 unknown_cmnd:
2027 		common->data_size_from_cmnd = 0;
2028 		sprintf(unknown, "Unknown x%02x", common->cmnd[0]);
2029 		reply = check_command(common, common->cmnd_size,
2030 				      DATA_DIR_UNKNOWN, 0xff, 0, unknown);
2031 		if (reply == 0) {
2032 			curlun->sense_data = SS_INVALID_COMMAND;
2033 			reply = -EINVAL;
2034 		}
2035 		break;
2036 	}
2037 	up_read(&common->filesem);
2038 
2039 	if (reply == -EINTR)
2040 		return -EINTR;
2041 
2042 	/* Set up the single reply buffer for finish_reply() */
2043 	if (reply == -EINVAL)
2044 		reply = 0;		/* Error reply length */
2045 	if (reply >= 0 && common->data_dir == DATA_DIR_TO_HOST) {
2046 		reply = min((u32) reply, common->data_size_from_cmnd);
2047 		bh->inreq->length = reply;
2048 		bh->state = BUF_STATE_FULL;
2049 		common->residue -= reply;
2050 	}				/* Otherwise it's already set */
2051 
2052 	return 0;
2053 }
2054 
2055 /*-------------------------------------------------------------------------*/
2056 
2057 static int received_cbw(struct fsg_dev *fsg, struct fsg_buffhd *bh)
2058 {
2059 	struct usb_request	*req = bh->outreq;
2060 	struct fsg_bulk_cb_wrap	*cbw = req->buf;
2061 	struct fsg_common	*common = fsg->common;
2062 
2063 	/* Was this a real packet?  Should it be ignored? */
2064 	if (req->status || test_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags))
2065 		return -EINVAL;
2066 
2067 	/* Is the CBW valid? */
2068 	if (req->actual != USB_BULK_CB_WRAP_LEN ||
2069 			cbw->Signature != cpu_to_le32(
2070 				USB_BULK_CB_SIG)) {
2071 		DBG(fsg, "invalid CBW: len %u sig 0x%x\n",
2072 				req->actual,
2073 				le32_to_cpu(cbw->Signature));
2074 
2075 		/* The Bulk-only spec says we MUST stall the IN endpoint
2076 		 * (6.6.1), so it's unavoidable.  It also says we must
2077 		 * retain this state until the next reset, but there's
2078 		 * no way to tell the controller driver it should ignore
2079 		 * Clear-Feature(HALT) requests.
2080 		 *
2081 		 * We aren't required to halt the OUT endpoint; instead
2082 		 * we can simply accept and discard any data received
2083 		 * until the next reset. */
2084 		wedge_bulk_in_endpoint(fsg);
2085 		set_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
2086 		return -EINVAL;
2087 	}
2088 
2089 	/* Is the CBW meaningful? */
2090 	if (cbw->Lun >= FSG_MAX_LUNS || cbw->Flags & ~USB_BULK_IN_FLAG ||
2091 			cbw->Length <= 0 || cbw->Length > MAX_COMMAND_SIZE) {
2092 		DBG(fsg, "non-meaningful CBW: lun = %u, flags = 0x%x, "
2093 				"cmdlen %u\n",
2094 				cbw->Lun, cbw->Flags, cbw->Length);
2095 
2096 		/* We can do anything we want here, so let's stall the
2097 		 * bulk pipes if we are allowed to. */
2098 		if (common->can_stall) {
2099 			fsg_set_halt(fsg, fsg->bulk_out);
2100 			halt_bulk_in_endpoint(fsg);
2101 		}
2102 		return -EINVAL;
2103 	}
2104 
2105 	/* Save the command for later */
2106 	common->cmnd_size = cbw->Length;
2107 	memcpy(common->cmnd, cbw->CDB, common->cmnd_size);
2108 	if (cbw->Flags & USB_BULK_IN_FLAG)
2109 		common->data_dir = DATA_DIR_TO_HOST;
2110 	else
2111 		common->data_dir = DATA_DIR_FROM_HOST;
2112 	common->data_size = le32_to_cpu(cbw->DataTransferLength);
2113 	if (common->data_size == 0)
2114 		common->data_dir = DATA_DIR_NONE;
2115 	common->lun = cbw->Lun;
2116 	common->tag = cbw->Tag;
2117 	return 0;
2118 }
2119 
2120 
2121 static int get_next_command(struct fsg_common *common)
2122 {
2123 	struct fsg_buffhd	*bh;
2124 	int			rc = 0;
2125 
2126 	/* Wait for the next buffer to become available */
2127 	bh = common->next_buffhd_to_fill;
2128 	while (bh->state != BUF_STATE_EMPTY) {
2129 		rc = sleep_thread(common);
2130 		if (rc)
2131 			return rc;
2132 	}
2133 
2134 	/* Queue a request to read a Bulk-only CBW */
2135 	set_bulk_out_req_length(common, bh, USB_BULK_CB_WRAP_LEN);
2136 	bh->outreq->short_not_ok = 1;
2137 	START_TRANSFER_OR(common, bulk_out, bh->outreq,
2138 			  &bh->outreq_busy, &bh->state)
2139 		/* Don't know what to do if common->fsg is NULL */
2140 		return -EIO;
2141 
2142 	/* We will drain the buffer in software, which means we
2143 	 * can reuse it for the next filling.  No need to advance
2144 	 * next_buffhd_to_fill. */
2145 
2146 	/* Wait for the CBW to arrive */
2147 	while (bh->state != BUF_STATE_FULL) {
2148 		rc = sleep_thread(common);
2149 		if (rc)
2150 			return rc;
2151 	}
2152 
2153 	rc = fsg_is_set(common) ? received_cbw(common->fsg, bh) : -EIO;
2154 	bh->state = BUF_STATE_EMPTY;
2155 
2156 	return rc;
2157 }
2158 
2159 
2160 /*-------------------------------------------------------------------------*/
2161 
2162 static int enable_endpoint(struct fsg_common *common, struct usb_ep *ep,
2163 		const struct usb_endpoint_descriptor *d)
2164 {
2165 	int	rc;
2166 
2167 	ep->driver_data = common;
2168 	rc = usb_ep_enable(ep, d);
2169 	if (rc)
2170 		ERROR(common, "can't enable %s, result %d\n", ep->name, rc);
2171 	return rc;
2172 }
2173 
2174 static int alloc_request(struct fsg_common *common, struct usb_ep *ep,
2175 		struct usb_request **preq)
2176 {
2177 	*preq = usb_ep_alloc_request(ep, GFP_ATOMIC);
2178 	if (*preq)
2179 		return 0;
2180 	ERROR(common, "can't allocate request for %s\n", ep->name);
2181 	return -ENOMEM;
2182 }
2183 
2184 /* Reset interface setting and re-init endpoint state (toggle etc). */
2185 static int do_set_interface(struct fsg_common *common, struct fsg_dev *new_fsg)
2186 {
2187 	const struct usb_endpoint_descriptor *d;
2188 	struct fsg_dev *fsg;
2189 	int i, rc = 0;
2190 
2191 	if (common->running)
2192 		DBG(common, "reset interface\n");
2193 
2194 reset:
2195 	/* Deallocate the requests */
2196 	if (common->fsg) {
2197 		fsg = common->fsg;
2198 
2199 		for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
2200 			struct fsg_buffhd *bh = &common->buffhds[i];
2201 
2202 			if (bh->inreq) {
2203 				usb_ep_free_request(fsg->bulk_in, bh->inreq);
2204 				bh->inreq = NULL;
2205 			}
2206 			if (bh->outreq) {
2207 				usb_ep_free_request(fsg->bulk_out, bh->outreq);
2208 				bh->outreq = NULL;
2209 			}
2210 		}
2211 
2212 		/* Disable the endpoints */
2213 		if (fsg->bulk_in_enabled) {
2214 			usb_ep_disable(fsg->bulk_in);
2215 			fsg->bulk_in_enabled = 0;
2216 		}
2217 		if (fsg->bulk_out_enabled) {
2218 			usb_ep_disable(fsg->bulk_out);
2219 			fsg->bulk_out_enabled = 0;
2220 		}
2221 
2222 		common->fsg = NULL;
2223 		/* wake_up(&common->fsg_wait); */
2224 	}
2225 
2226 	common->running = 0;
2227 	if (!new_fsg || rc)
2228 		return rc;
2229 
2230 	common->fsg = new_fsg;
2231 	fsg = common->fsg;
2232 
2233 	/* Enable the endpoints */
2234 	d = fsg_ep_desc(common->gadget,
2235 			&fsg_fs_bulk_in_desc, &fsg_hs_bulk_in_desc);
2236 	rc = enable_endpoint(common, fsg->bulk_in, d);
2237 	if (rc)
2238 		goto reset;
2239 	fsg->bulk_in_enabled = 1;
2240 
2241 	d = fsg_ep_desc(common->gadget,
2242 			&fsg_fs_bulk_out_desc, &fsg_hs_bulk_out_desc);
2243 	rc = enable_endpoint(common, fsg->bulk_out, d);
2244 	if (rc)
2245 		goto reset;
2246 	fsg->bulk_out_enabled = 1;
2247 	common->bulk_out_maxpacket =
2248 				le16_to_cpu(get_unaligned(&d->wMaxPacketSize));
2249 	clear_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
2250 
2251 	/* Allocate the requests */
2252 	for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
2253 		struct fsg_buffhd	*bh = &common->buffhds[i];
2254 
2255 		rc = alloc_request(common, fsg->bulk_in, &bh->inreq);
2256 		if (rc)
2257 			goto reset;
2258 		rc = alloc_request(common, fsg->bulk_out, &bh->outreq);
2259 		if (rc)
2260 			goto reset;
2261 		bh->inreq->buf = bh->outreq->buf = bh->buf;
2262 		bh->inreq->context = bh->outreq->context = bh;
2263 		bh->inreq->complete = bulk_in_complete;
2264 		bh->outreq->complete = bulk_out_complete;
2265 	}
2266 
2267 	common->running = 1;
2268 
2269 	return rc;
2270 }
2271 
2272 
2273 /****************************** ALT CONFIGS ******************************/
2274 
2275 
2276 static int fsg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
2277 {
2278 	struct fsg_dev *fsg = fsg_from_func(f);
2279 	fsg->common->new_fsg = fsg;
2280 	raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
2281 	return 0;
2282 }
2283 
2284 static void fsg_disable(struct usb_function *f)
2285 {
2286 	struct fsg_dev *fsg = fsg_from_func(f);
2287 	fsg->common->new_fsg = NULL;
2288 	raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
2289 }
2290 
2291 /*-------------------------------------------------------------------------*/
2292 
2293 static void handle_exception(struct fsg_common *common)
2294 {
2295 	int			i;
2296 	struct fsg_buffhd	*bh;
2297 	enum fsg_state		old_state;
2298 	struct fsg_lun		*curlun;
2299 	unsigned int		exception_req_tag;
2300 
2301 	/* Cancel all the pending transfers */
2302 	if (common->fsg) {
2303 		for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
2304 			bh = &common->buffhds[i];
2305 			if (bh->inreq_busy)
2306 				usb_ep_dequeue(common->fsg->bulk_in, bh->inreq);
2307 			if (bh->outreq_busy)
2308 				usb_ep_dequeue(common->fsg->bulk_out,
2309 					       bh->outreq);
2310 		}
2311 
2312 		/* Wait until everything is idle */
2313 		for (;;) {
2314 			int num_active = 0;
2315 			for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
2316 				bh = &common->buffhds[i];
2317 				num_active += bh->inreq_busy + bh->outreq_busy;
2318 			}
2319 			if (num_active == 0)
2320 				break;
2321 			if (sleep_thread(common))
2322 				return;
2323 		}
2324 
2325 		/* Clear out the controller's fifos */
2326 		if (common->fsg->bulk_in_enabled)
2327 			usb_ep_fifo_flush(common->fsg->bulk_in);
2328 		if (common->fsg->bulk_out_enabled)
2329 			usb_ep_fifo_flush(common->fsg->bulk_out);
2330 	}
2331 
2332 	/* Reset the I/O buffer states and pointers, the SCSI
2333 	 * state, and the exception.  Then invoke the handler. */
2334 
2335 	for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
2336 		bh = &common->buffhds[i];
2337 		bh->state = BUF_STATE_EMPTY;
2338 	}
2339 	common->next_buffhd_to_fill = &common->buffhds[0];
2340 	common->next_buffhd_to_drain = &common->buffhds[0];
2341 	exception_req_tag = common->exception_req_tag;
2342 	old_state = common->state;
2343 
2344 	if (old_state == FSG_STATE_ABORT_BULK_OUT)
2345 		common->state = FSG_STATE_STATUS_PHASE;
2346 	else {
2347 		for (i = 0; i < common->nluns; ++i) {
2348 			curlun = &common->luns[i];
2349 			curlun->sense_data = SS_NO_SENSE;
2350 			curlun->info_valid = 0;
2351 		}
2352 		common->state = FSG_STATE_IDLE;
2353 	}
2354 
2355 	/* Carry out any extra actions required for the exception */
2356 	switch (old_state) {
2357 	case FSG_STATE_ABORT_BULK_OUT:
2358 		send_status(common);
2359 
2360 		if (common->state == FSG_STATE_STATUS_PHASE)
2361 			common->state = FSG_STATE_IDLE;
2362 		break;
2363 
2364 	case FSG_STATE_RESET:
2365 		/* In case we were forced against our will to halt a
2366 		 * bulk endpoint, clear the halt now.  (The SuperH UDC
2367 		 * requires this.) */
2368 		if (!fsg_is_set(common))
2369 			break;
2370 		if (test_and_clear_bit(IGNORE_BULK_OUT,
2371 				       &common->fsg->atomic_bitflags))
2372 			usb_ep_clear_halt(common->fsg->bulk_in);
2373 
2374 		if (common->ep0_req_tag == exception_req_tag)
2375 			ep0_queue(common);	/* Complete the status stage */
2376 
2377 		break;
2378 
2379 	case FSG_STATE_CONFIG_CHANGE:
2380 		do_set_interface(common, common->new_fsg);
2381 		break;
2382 
2383 	case FSG_STATE_EXIT:
2384 	case FSG_STATE_TERMINATED:
2385 		do_set_interface(common, NULL);		/* Free resources */
2386 		common->state = FSG_STATE_TERMINATED;	/* Stop the thread */
2387 		break;
2388 
2389 	case FSG_STATE_INTERFACE_CHANGE:
2390 	case FSG_STATE_DISCONNECT:
2391 	case FSG_STATE_COMMAND_PHASE:
2392 	case FSG_STATE_DATA_PHASE:
2393 	case FSG_STATE_STATUS_PHASE:
2394 	case FSG_STATE_IDLE:
2395 		break;
2396 	}
2397 }
2398 
2399 /*-------------------------------------------------------------------------*/
2400 
2401 int fsg_main_thread(void *common_)
2402 {
2403 	int ret;
2404 	struct fsg_common	*common = the_fsg_common;
2405 	/* The main loop */
2406 	do {
2407 		if (exception_in_progress(common)) {
2408 			handle_exception(common);
2409 			continue;
2410 		}
2411 
2412 		if (!common->running) {
2413 			ret = sleep_thread(common);
2414 			if (ret)
2415 				return ret;
2416 
2417 			continue;
2418 		}
2419 
2420 		ret = get_next_command(common);
2421 		if (ret)
2422 			return ret;
2423 
2424 		if (!exception_in_progress(common))
2425 			common->state = FSG_STATE_DATA_PHASE;
2426 
2427 		if (do_scsi_command(common) || finish_reply(common))
2428 			continue;
2429 
2430 		if (!exception_in_progress(common))
2431 			common->state = FSG_STATE_STATUS_PHASE;
2432 
2433 		if (send_status(common))
2434 			continue;
2435 
2436 		if (!exception_in_progress(common))
2437 			common->state = FSG_STATE_IDLE;
2438 	} while (0);
2439 
2440 	common->thread_task = NULL;
2441 
2442 	return 0;
2443 }
2444 
2445 static void fsg_common_release(struct kref *ref);
2446 
2447 static struct fsg_common *fsg_common_init(struct fsg_common *common,
2448 					  struct usb_composite_dev *cdev)
2449 {
2450 	struct usb_gadget *gadget = cdev->gadget;
2451 	struct fsg_buffhd *bh;
2452 	struct fsg_lun *curlun;
2453 	int nluns, i, rc;
2454 
2455 	/* Find out how many LUNs there should be */
2456 	nluns = 1;
2457 	if (nluns < 1 || nluns > FSG_MAX_LUNS) {
2458 		printf("invalid number of LUNs: %u\n", nluns);
2459 		return ERR_PTR(-EINVAL);
2460 	}
2461 
2462 	/* Allocate? */
2463 	if (!common) {
2464 		common = calloc(sizeof *common, 1);
2465 		if (!common)
2466 			return ERR_PTR(-ENOMEM);
2467 		common->free_storage_on_release = 1;
2468 	} else {
2469 		memset(common, 0, sizeof common);
2470 		common->free_storage_on_release = 0;
2471 	}
2472 
2473 	common->ops = NULL;
2474 	common->private_data = NULL;
2475 
2476 	common->gadget = gadget;
2477 	common->ep0 = gadget->ep0;
2478 	common->ep0req = cdev->req;
2479 
2480 	/* Maybe allocate device-global string IDs, and patch descriptors */
2481 	if (fsg_strings[FSG_STRING_INTERFACE].id == 0) {
2482 		rc = usb_string_id(cdev);
2483 		if (unlikely(rc < 0))
2484 			goto error_release;
2485 		fsg_strings[FSG_STRING_INTERFACE].id = rc;
2486 		fsg_intf_desc.iInterface = rc;
2487 	}
2488 
2489 	/* Create the LUNs, open their backing files, and register the
2490 	 * LUN devices in sysfs. */
2491 	curlun = calloc(nluns, sizeof *curlun);
2492 	if (!curlun) {
2493 		rc = -ENOMEM;
2494 		goto error_release;
2495 	}
2496 	common->nluns = nluns;
2497 
2498 	for (i = 0; i < nluns; i++) {
2499 		common->luns[i].removable = 1;
2500 
2501 		rc = fsg_lun_open(&common->luns[i], "");
2502 		if (rc)
2503 			goto error_luns;
2504 	}
2505 	common->lun = 0;
2506 
2507 	/* Data buffers cyclic list */
2508 	bh = common->buffhds;
2509 
2510 	i = FSG_NUM_BUFFERS;
2511 	goto buffhds_first_it;
2512 	do {
2513 		bh->next = bh + 1;
2514 		++bh;
2515 buffhds_first_it:
2516 		bh->inreq_busy = 0;
2517 		bh->outreq_busy = 0;
2518 		bh->buf = kmalloc(FSG_BUFLEN, GFP_KERNEL);
2519 		if (unlikely(!bh->buf)) {
2520 			rc = -ENOMEM;
2521 			goto error_release;
2522 		}
2523 	} while (--i);
2524 	bh->next = common->buffhds;
2525 
2526 	snprintf(common->inquiry_string, sizeof common->inquiry_string,
2527 		 "%-8s%-16s%04x",
2528 		 "Linux   ",
2529 		 "File-Store Gadget",
2530 		 0xffff);
2531 
2532 	/* Some peripheral controllers are known not to be able to
2533 	 * halt bulk endpoints correctly.  If one of them is present,
2534 	 * disable stalls.
2535 	 */
2536 
2537 	/* Tell the thread to start working */
2538 	common->thread_task =
2539 		kthread_create(fsg_main_thread, common,
2540 			       OR(cfg->thread_name, "file-storage"));
2541 	if (IS_ERR(common->thread_task)) {
2542 		rc = PTR_ERR(common->thread_task);
2543 		goto error_release;
2544 	}
2545 
2546 #undef OR
2547 	/* Information */
2548 	INFO(common, FSG_DRIVER_DESC ", version: " FSG_DRIVER_VERSION "\n");
2549 	INFO(common, "Number of LUNs=%d\n", common->nluns);
2550 
2551 	return common;
2552 
2553 error_luns:
2554 	common->nluns = i + 1;
2555 error_release:
2556 	common->state = FSG_STATE_TERMINATED;	/* The thread is dead */
2557 	/* Call fsg_common_release() directly, ref might be not
2558 	 * initialised */
2559 	fsg_common_release(&common->ref);
2560 	return ERR_PTR(rc);
2561 }
2562 
2563 static void fsg_common_release(struct kref *ref)
2564 {
2565 	struct fsg_common *common = container_of(ref, struct fsg_common, ref);
2566 
2567 	/* If the thread isn't already dead, tell it to exit now */
2568 	if (common->state != FSG_STATE_TERMINATED) {
2569 		raise_exception(common, FSG_STATE_EXIT);
2570 		wait_for_completion(&common->thread_notifier);
2571 	}
2572 
2573 	if (likely(common->luns)) {
2574 		struct fsg_lun *lun = common->luns;
2575 		unsigned i = common->nluns;
2576 
2577 		/* In error recovery common->nluns may be zero. */
2578 		for (; i; --i, ++lun)
2579 			fsg_lun_close(lun);
2580 
2581 		kfree(common->luns);
2582 	}
2583 
2584 	{
2585 		struct fsg_buffhd *bh = common->buffhds;
2586 		unsigned i = FSG_NUM_BUFFERS;
2587 		do {
2588 			kfree(bh->buf);
2589 		} while (++bh, --i);
2590 	}
2591 
2592 	if (common->free_storage_on_release)
2593 		kfree(common);
2594 }
2595 
2596 
2597 /*-------------------------------------------------------------------------*/
2598 
2599 /**
2600  * usb_copy_descriptors - copy a vector of USB descriptors
2601  * @src: null-terminated vector to copy
2602  * Context: initialization code, which may sleep
2603  *
2604  * This makes a copy of a vector of USB descriptors.  Its primary use
2605  * is to support usb_function objects which can have multiple copies,
2606  * each needing different descriptors.  Functions may have static
2607  * tables of descriptors, which are used as templates and customized
2608  * with identifiers (for interfaces, strings, endpoints, and more)
2609  * as needed by a given function instance.
2610  */
2611 struct usb_descriptor_header **
2612 usb_copy_descriptors(struct usb_descriptor_header **src)
2613 {
2614 	struct usb_descriptor_header **tmp;
2615 	unsigned bytes;
2616 	unsigned n_desc;
2617 	void *mem;
2618 	struct usb_descriptor_header **ret;
2619 
2620 	/* count descriptors and their sizes; then add vector size */
2621 	for (bytes = 0, n_desc = 0, tmp = src; *tmp; tmp++, n_desc++)
2622 		bytes += (*tmp)->bLength;
2623 	bytes += (n_desc + 1) * sizeof(*tmp);
2624 
2625 	mem = kmalloc(bytes, GFP_KERNEL);
2626 	if (!mem)
2627 		return NULL;
2628 
2629 	/* fill in pointers starting at "tmp",
2630 	 * to descriptors copied starting at "mem";
2631 	 * and return "ret"
2632 	 */
2633 	tmp = mem;
2634 	ret = mem;
2635 	mem += (n_desc + 1) * sizeof(*tmp);
2636 	while (*src) {
2637 		memcpy(mem, *src, (*src)->bLength);
2638 		*tmp = mem;
2639 		tmp++;
2640 		mem += (*src)->bLength;
2641 		src++;
2642 	}
2643 	*tmp = NULL;
2644 
2645 	return ret;
2646 }
2647 
2648 static void fsg_unbind(struct usb_configuration *c, struct usb_function *f)
2649 {
2650 	struct fsg_dev		*fsg = fsg_from_func(f);
2651 
2652 	DBG(fsg, "unbind\n");
2653 	if (fsg->common->fsg == fsg) {
2654 		fsg->common->new_fsg = NULL;
2655 		raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
2656 	}
2657 
2658 	free(fsg->function.descriptors);
2659 	free(fsg->function.hs_descriptors);
2660 	kfree(fsg);
2661 }
2662 
2663 static int fsg_bind(struct usb_configuration *c, struct usb_function *f)
2664 {
2665 	struct fsg_dev		*fsg = fsg_from_func(f);
2666 	struct usb_gadget	*gadget = c->cdev->gadget;
2667 	int			i;
2668 	struct usb_ep		*ep;
2669 	fsg->gadget = gadget;
2670 
2671 	/* New interface */
2672 	i = usb_interface_id(c, f);
2673 	if (i < 0)
2674 		return i;
2675 	fsg_intf_desc.bInterfaceNumber = i;
2676 	fsg->interface_number = i;
2677 
2678 	/* Find all the endpoints we will use */
2679 	ep = usb_ep_autoconfig(gadget, &fsg_fs_bulk_in_desc);
2680 	if (!ep)
2681 		goto autoconf_fail;
2682 	ep->driver_data = fsg->common;	/* claim the endpoint */
2683 	fsg->bulk_in = ep;
2684 
2685 	ep = usb_ep_autoconfig(gadget, &fsg_fs_bulk_out_desc);
2686 	if (!ep)
2687 		goto autoconf_fail;
2688 	ep->driver_data = fsg->common;	/* claim the endpoint */
2689 	fsg->bulk_out = ep;
2690 
2691 	/* Copy descriptors */
2692 	f->descriptors = usb_copy_descriptors(fsg_fs_function);
2693 	if (unlikely(!f->descriptors))
2694 		return -ENOMEM;
2695 
2696 	if (gadget_is_dualspeed(gadget)) {
2697 		/* Assume endpoint addresses are the same for both speeds */
2698 		fsg_hs_bulk_in_desc.bEndpointAddress =
2699 			fsg_fs_bulk_in_desc.bEndpointAddress;
2700 		fsg_hs_bulk_out_desc.bEndpointAddress =
2701 			fsg_fs_bulk_out_desc.bEndpointAddress;
2702 		f->hs_descriptors = usb_copy_descriptors(fsg_hs_function);
2703 		if (unlikely(!f->hs_descriptors)) {
2704 			free(f->descriptors);
2705 			return -ENOMEM;
2706 		}
2707 	}
2708 	return 0;
2709 
2710 autoconf_fail:
2711 	ERROR(fsg, "unable to autoconfigure all endpoints\n");
2712 	return -ENOTSUPP;
2713 }
2714 
2715 
2716 /****************************** ADD FUNCTION ******************************/
2717 
2718 static struct usb_gadget_strings *fsg_strings_array[] = {
2719 	&fsg_stringtab,
2720 	NULL,
2721 };
2722 
2723 static int fsg_bind_config(struct usb_composite_dev *cdev,
2724 			   struct usb_configuration *c,
2725 			   struct fsg_common *common)
2726 {
2727 	struct fsg_dev *fsg;
2728 	int rc;
2729 
2730 	fsg = calloc(1, sizeof *fsg);
2731 	if (!fsg)
2732 		return -ENOMEM;
2733 	fsg->function.name        = FSG_DRIVER_DESC;
2734 	fsg->function.strings     = fsg_strings_array;
2735 	fsg->function.bind        = fsg_bind;
2736 	fsg->function.unbind      = fsg_unbind;
2737 	fsg->function.setup       = fsg_setup;
2738 	fsg->function.set_alt     = fsg_set_alt;
2739 	fsg->function.disable     = fsg_disable;
2740 
2741 	fsg->common               = common;
2742 	common->fsg               = fsg;
2743 	/* Our caller holds a reference to common structure so we
2744 	 * don't have to be worry about it being freed until we return
2745 	 * from this function.  So instead of incrementing counter now
2746 	 * and decrement in error recovery we increment it only when
2747 	 * call to usb_add_function() was successful. */
2748 
2749 	rc = usb_add_function(c, &fsg->function);
2750 
2751 	if (rc)
2752 		kfree(fsg);
2753 
2754 	return rc;
2755 }
2756 
2757 int fsg_add(struct usb_configuration *c)
2758 {
2759 	struct fsg_common *fsg_common;
2760 
2761 	fsg_common = fsg_common_init(NULL, c->cdev);
2762 
2763 	fsg_common->vendor_name = 0;
2764 	fsg_common->product_name = 0;
2765 	fsg_common->release = 0xffff;
2766 
2767 	fsg_common->ops = NULL;
2768 	fsg_common->private_data = NULL;
2769 
2770 	the_fsg_common = fsg_common;
2771 
2772 	return fsg_bind_config(c->cdev, c, fsg_common);
2773 }
2774 
2775 int fsg_init(struct ums *ums_dev)
2776 {
2777 	ums = ums_dev;
2778 
2779 	return 0;
2780 }
2781