xref: /openbmc/linux/drivers/usb/gadget/function/f_fs.c (revision 98ddec80)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * f_fs.c -- user mode file system API for USB composite function controllers
4  *
5  * Copyright (C) 2010 Samsung Electronics
6  * Author: Michal Nazarewicz <mina86@mina86.com>
7  *
8  * Based on inode.c (GadgetFS) which was:
9  * Copyright (C) 2003-2004 David Brownell
10  * Copyright (C) 2003 Agilent Technologies
11  */
12 
13 
14 /* #define DEBUG */
15 /* #define VERBOSE_DEBUG */
16 
17 #include <linux/blkdev.h>
18 #include <linux/pagemap.h>
19 #include <linux/export.h>
20 #include <linux/hid.h>
21 #include <linux/module.h>
22 #include <linux/sched/signal.h>
23 #include <linux/uio.h>
24 #include <asm/unaligned.h>
25 
26 #include <linux/usb/composite.h>
27 #include <linux/usb/functionfs.h>
28 
29 #include <linux/aio.h>
30 #include <linux/mmu_context.h>
31 #include <linux/poll.h>
32 #include <linux/eventfd.h>
33 
34 #include "u_fs.h"
35 #include "u_f.h"
36 #include "u_os_desc.h"
37 #include "configfs.h"
38 
39 #define FUNCTIONFS_MAGIC	0xa647361 /* Chosen by a honest dice roll ;) */
40 
41 /* Reference counter handling */
42 static void ffs_data_get(struct ffs_data *ffs);
43 static void ffs_data_put(struct ffs_data *ffs);
44 /* Creates new ffs_data object. */
45 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
46 	__attribute__((malloc));
47 
48 /* Opened counter handling. */
49 static void ffs_data_opened(struct ffs_data *ffs);
50 static void ffs_data_closed(struct ffs_data *ffs);
51 
52 /* Called with ffs->mutex held; take over ownership of data. */
53 static int __must_check
54 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
55 static int __must_check
56 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
57 
58 
59 /* The function structure ***************************************************/
60 
61 struct ffs_ep;
62 
63 struct ffs_function {
64 	struct usb_configuration	*conf;
65 	struct usb_gadget		*gadget;
66 	struct ffs_data			*ffs;
67 
68 	struct ffs_ep			*eps;
69 	u8				eps_revmap[16];
70 	short				*interfaces_nums;
71 
72 	struct usb_function		function;
73 };
74 
75 
76 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
77 {
78 	return container_of(f, struct ffs_function, function);
79 }
80 
81 
82 static inline enum ffs_setup_state
83 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
84 {
85 	return (enum ffs_setup_state)
86 		cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
87 }
88 
89 
90 static void ffs_func_eps_disable(struct ffs_function *func);
91 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
92 
93 static int ffs_func_bind(struct usb_configuration *,
94 			 struct usb_function *);
95 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
96 static void ffs_func_disable(struct usb_function *);
97 static int ffs_func_setup(struct usb_function *,
98 			  const struct usb_ctrlrequest *);
99 static bool ffs_func_req_match(struct usb_function *,
100 			       const struct usb_ctrlrequest *,
101 			       bool config0);
102 static void ffs_func_suspend(struct usb_function *);
103 static void ffs_func_resume(struct usb_function *);
104 
105 
106 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
107 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
108 
109 
110 /* The endpoints structures *************************************************/
111 
112 struct ffs_ep {
113 	struct usb_ep			*ep;	/* P: ffs->eps_lock */
114 	struct usb_request		*req;	/* P: epfile->mutex */
115 
116 	/* [0]: full speed, [1]: high speed, [2]: super speed */
117 	struct usb_endpoint_descriptor	*descs[3];
118 
119 	u8				num;
120 
121 	int				status;	/* P: epfile->mutex */
122 };
123 
124 struct ffs_epfile {
125 	/* Protects ep->ep and ep->req. */
126 	struct mutex			mutex;
127 
128 	struct ffs_data			*ffs;
129 	struct ffs_ep			*ep;	/* P: ffs->eps_lock */
130 
131 	struct dentry			*dentry;
132 
133 	/*
134 	 * Buffer for holding data from partial reads which may happen since
135 	 * we’re rounding user read requests to a multiple of a max packet size.
136 	 *
137 	 * The pointer is initialised with NULL value and may be set by
138 	 * __ffs_epfile_read_data function to point to a temporary buffer.
139 	 *
140 	 * In normal operation, calls to __ffs_epfile_read_buffered will consume
141 	 * data from said buffer and eventually free it.  Importantly, while the
142 	 * function is using the buffer, it sets the pointer to NULL.  This is
143 	 * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
144 	 * can never run concurrently (they are synchronised by epfile->mutex)
145 	 * so the latter will not assign a new value to the pointer.
146 	 *
147 	 * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
148 	 * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
149 	 * value is crux of the synchronisation between ffs_func_eps_disable and
150 	 * __ffs_epfile_read_data.
151 	 *
152 	 * Once __ffs_epfile_read_data is about to finish it will try to set the
153 	 * pointer back to its old value (as described above), but seeing as the
154 	 * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
155 	 * the buffer.
156 	 *
157 	 * == State transitions ==
158 	 *
159 	 * • ptr == NULL:  (initial state)
160 	 *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
161 	 *   ◦ __ffs_epfile_read_buffered:    nop
162 	 *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
163 	 *   ◦ reading finishes:              n/a, not in ‘and reading’ state
164 	 * • ptr == DROP:
165 	 *   ◦ __ffs_epfile_read_buffer_free: nop
166 	 *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
167 	 *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
168 	 *   ◦ reading finishes:              n/a, not in ‘and reading’ state
169 	 * • ptr == buf:
170 	 *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
171 	 *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
172 	 *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
173 	 *                                    is always called first
174 	 *   ◦ reading finishes:              n/a, not in ‘and reading’ state
175 	 * • ptr == NULL and reading:
176 	 *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
177 	 *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
178 	 *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
179 	 *   ◦ reading finishes and …
180 	 *     … all data read:               free buf, go to ptr == NULL
181 	 *     … otherwise:                   go to ptr == buf and reading
182 	 * • ptr == DROP and reading:
183 	 *   ◦ __ffs_epfile_read_buffer_free: nop
184 	 *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
185 	 *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
186 	 *   ◦ reading finishes:              free buf, go to ptr == DROP
187 	 */
188 	struct ffs_buffer		*read_buffer;
189 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
190 
191 	char				name[5];
192 
193 	unsigned char			in;	/* P: ffs->eps_lock */
194 	unsigned char			isoc;	/* P: ffs->eps_lock */
195 
196 	unsigned char			_pad;
197 };
198 
199 struct ffs_buffer {
200 	size_t length;
201 	char *data;
202 	char storage[];
203 };
204 
205 /*  ffs_io_data structure ***************************************************/
206 
207 struct ffs_io_data {
208 	bool aio;
209 	bool read;
210 
211 	struct kiocb *kiocb;
212 	struct iov_iter data;
213 	const void *to_free;
214 	char *buf;
215 
216 	struct mm_struct *mm;
217 	struct work_struct work;
218 
219 	struct usb_ep *ep;
220 	struct usb_request *req;
221 
222 	struct ffs_data *ffs;
223 };
224 
225 struct ffs_desc_helper {
226 	struct ffs_data *ffs;
227 	unsigned interfaces_count;
228 	unsigned eps_count;
229 };
230 
231 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
232 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
233 
234 static struct dentry *
235 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
236 		   const struct file_operations *fops);
237 
238 /* Devices management *******************************************************/
239 
240 DEFINE_MUTEX(ffs_lock);
241 EXPORT_SYMBOL_GPL(ffs_lock);
242 
243 static struct ffs_dev *_ffs_find_dev(const char *name);
244 static struct ffs_dev *_ffs_alloc_dev(void);
245 static void _ffs_free_dev(struct ffs_dev *dev);
246 static void *ffs_acquire_dev(const char *dev_name);
247 static void ffs_release_dev(struct ffs_data *ffs_data);
248 static int ffs_ready(struct ffs_data *ffs);
249 static void ffs_closed(struct ffs_data *ffs);
250 
251 /* Misc helper functions ****************************************************/
252 
253 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
254 	__attribute__((warn_unused_result, nonnull));
255 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
256 	__attribute__((warn_unused_result, nonnull));
257 
258 
259 /* Control file aka ep0 *****************************************************/
260 
261 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
262 {
263 	struct ffs_data *ffs = req->context;
264 
265 	complete(&ffs->ep0req_completion);
266 }
267 
268 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
269 	__releases(&ffs->ev.waitq.lock)
270 {
271 	struct usb_request *req = ffs->ep0req;
272 	int ret;
273 
274 	req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
275 
276 	spin_unlock_irq(&ffs->ev.waitq.lock);
277 
278 	req->buf      = data;
279 	req->length   = len;
280 
281 	/*
282 	 * UDC layer requires to provide a buffer even for ZLP, but should
283 	 * not use it at all. Let's provide some poisoned pointer to catch
284 	 * possible bug in the driver.
285 	 */
286 	if (req->buf == NULL)
287 		req->buf = (void *)0xDEADBABE;
288 
289 	reinit_completion(&ffs->ep0req_completion);
290 
291 	ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
292 	if (unlikely(ret < 0))
293 		return ret;
294 
295 	ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
296 	if (unlikely(ret)) {
297 		usb_ep_dequeue(ffs->gadget->ep0, req);
298 		return -EINTR;
299 	}
300 
301 	ffs->setup_state = FFS_NO_SETUP;
302 	return req->status ? req->status : req->actual;
303 }
304 
305 static int __ffs_ep0_stall(struct ffs_data *ffs)
306 {
307 	if (ffs->ev.can_stall) {
308 		pr_vdebug("ep0 stall\n");
309 		usb_ep_set_halt(ffs->gadget->ep0);
310 		ffs->setup_state = FFS_NO_SETUP;
311 		return -EL2HLT;
312 	} else {
313 		pr_debug("bogus ep0 stall!\n");
314 		return -ESRCH;
315 	}
316 }
317 
318 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
319 			     size_t len, loff_t *ptr)
320 {
321 	struct ffs_data *ffs = file->private_data;
322 	ssize_t ret;
323 	char *data;
324 
325 	ENTER();
326 
327 	/* Fast check if setup was canceled */
328 	if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
329 		return -EIDRM;
330 
331 	/* Acquire mutex */
332 	ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
333 	if (unlikely(ret < 0))
334 		return ret;
335 
336 	/* Check state */
337 	switch (ffs->state) {
338 	case FFS_READ_DESCRIPTORS:
339 	case FFS_READ_STRINGS:
340 		/* Copy data */
341 		if (unlikely(len < 16)) {
342 			ret = -EINVAL;
343 			break;
344 		}
345 
346 		data = ffs_prepare_buffer(buf, len);
347 		if (IS_ERR(data)) {
348 			ret = PTR_ERR(data);
349 			break;
350 		}
351 
352 		/* Handle data */
353 		if (ffs->state == FFS_READ_DESCRIPTORS) {
354 			pr_info("read descriptors\n");
355 			ret = __ffs_data_got_descs(ffs, data, len);
356 			if (unlikely(ret < 0))
357 				break;
358 
359 			ffs->state = FFS_READ_STRINGS;
360 			ret = len;
361 		} else {
362 			pr_info("read strings\n");
363 			ret = __ffs_data_got_strings(ffs, data, len);
364 			if (unlikely(ret < 0))
365 				break;
366 
367 			ret = ffs_epfiles_create(ffs);
368 			if (unlikely(ret)) {
369 				ffs->state = FFS_CLOSING;
370 				break;
371 			}
372 
373 			ffs->state = FFS_ACTIVE;
374 			mutex_unlock(&ffs->mutex);
375 
376 			ret = ffs_ready(ffs);
377 			if (unlikely(ret < 0)) {
378 				ffs->state = FFS_CLOSING;
379 				return ret;
380 			}
381 
382 			return len;
383 		}
384 		break;
385 
386 	case FFS_ACTIVE:
387 		data = NULL;
388 		/*
389 		 * We're called from user space, we can use _irq
390 		 * rather then _irqsave
391 		 */
392 		spin_lock_irq(&ffs->ev.waitq.lock);
393 		switch (ffs_setup_state_clear_cancelled(ffs)) {
394 		case FFS_SETUP_CANCELLED:
395 			ret = -EIDRM;
396 			goto done_spin;
397 
398 		case FFS_NO_SETUP:
399 			ret = -ESRCH;
400 			goto done_spin;
401 
402 		case FFS_SETUP_PENDING:
403 			break;
404 		}
405 
406 		/* FFS_SETUP_PENDING */
407 		if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
408 			spin_unlock_irq(&ffs->ev.waitq.lock);
409 			ret = __ffs_ep0_stall(ffs);
410 			break;
411 		}
412 
413 		/* FFS_SETUP_PENDING and not stall */
414 		len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
415 
416 		spin_unlock_irq(&ffs->ev.waitq.lock);
417 
418 		data = ffs_prepare_buffer(buf, len);
419 		if (IS_ERR(data)) {
420 			ret = PTR_ERR(data);
421 			break;
422 		}
423 
424 		spin_lock_irq(&ffs->ev.waitq.lock);
425 
426 		/*
427 		 * We are guaranteed to be still in FFS_ACTIVE state
428 		 * but the state of setup could have changed from
429 		 * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
430 		 * to check for that.  If that happened we copied data
431 		 * from user space in vain but it's unlikely.
432 		 *
433 		 * For sure we are not in FFS_NO_SETUP since this is
434 		 * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
435 		 * transition can be performed and it's protected by
436 		 * mutex.
437 		 */
438 		if (ffs_setup_state_clear_cancelled(ffs) ==
439 		    FFS_SETUP_CANCELLED) {
440 			ret = -EIDRM;
441 done_spin:
442 			spin_unlock_irq(&ffs->ev.waitq.lock);
443 		} else {
444 			/* unlocks spinlock */
445 			ret = __ffs_ep0_queue_wait(ffs, data, len);
446 		}
447 		kfree(data);
448 		break;
449 
450 	default:
451 		ret = -EBADFD;
452 		break;
453 	}
454 
455 	mutex_unlock(&ffs->mutex);
456 	return ret;
457 }
458 
459 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
460 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
461 				     size_t n)
462 	__releases(&ffs->ev.waitq.lock)
463 {
464 	/*
465 	 * n cannot be bigger than ffs->ev.count, which cannot be bigger than
466 	 * size of ffs->ev.types array (which is four) so that's how much space
467 	 * we reserve.
468 	 */
469 	struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
470 	const size_t size = n * sizeof *events;
471 	unsigned i = 0;
472 
473 	memset(events, 0, size);
474 
475 	do {
476 		events[i].type = ffs->ev.types[i];
477 		if (events[i].type == FUNCTIONFS_SETUP) {
478 			events[i].u.setup = ffs->ev.setup;
479 			ffs->setup_state = FFS_SETUP_PENDING;
480 		}
481 	} while (++i < n);
482 
483 	ffs->ev.count -= n;
484 	if (ffs->ev.count)
485 		memmove(ffs->ev.types, ffs->ev.types + n,
486 			ffs->ev.count * sizeof *ffs->ev.types);
487 
488 	spin_unlock_irq(&ffs->ev.waitq.lock);
489 	mutex_unlock(&ffs->mutex);
490 
491 	return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
492 }
493 
494 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
495 			    size_t len, loff_t *ptr)
496 {
497 	struct ffs_data *ffs = file->private_data;
498 	char *data = NULL;
499 	size_t n;
500 	int ret;
501 
502 	ENTER();
503 
504 	/* Fast check if setup was canceled */
505 	if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
506 		return -EIDRM;
507 
508 	/* Acquire mutex */
509 	ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
510 	if (unlikely(ret < 0))
511 		return ret;
512 
513 	/* Check state */
514 	if (ffs->state != FFS_ACTIVE) {
515 		ret = -EBADFD;
516 		goto done_mutex;
517 	}
518 
519 	/*
520 	 * We're called from user space, we can use _irq rather then
521 	 * _irqsave
522 	 */
523 	spin_lock_irq(&ffs->ev.waitq.lock);
524 
525 	switch (ffs_setup_state_clear_cancelled(ffs)) {
526 	case FFS_SETUP_CANCELLED:
527 		ret = -EIDRM;
528 		break;
529 
530 	case FFS_NO_SETUP:
531 		n = len / sizeof(struct usb_functionfs_event);
532 		if (unlikely(!n)) {
533 			ret = -EINVAL;
534 			break;
535 		}
536 
537 		if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
538 			ret = -EAGAIN;
539 			break;
540 		}
541 
542 		if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
543 							ffs->ev.count)) {
544 			ret = -EINTR;
545 			break;
546 		}
547 
548 		/* unlocks spinlock */
549 		return __ffs_ep0_read_events(ffs, buf,
550 					     min(n, (size_t)ffs->ev.count));
551 
552 	case FFS_SETUP_PENDING:
553 		if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
554 			spin_unlock_irq(&ffs->ev.waitq.lock);
555 			ret = __ffs_ep0_stall(ffs);
556 			goto done_mutex;
557 		}
558 
559 		len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
560 
561 		spin_unlock_irq(&ffs->ev.waitq.lock);
562 
563 		if (likely(len)) {
564 			data = kmalloc(len, GFP_KERNEL);
565 			if (unlikely(!data)) {
566 				ret = -ENOMEM;
567 				goto done_mutex;
568 			}
569 		}
570 
571 		spin_lock_irq(&ffs->ev.waitq.lock);
572 
573 		/* See ffs_ep0_write() */
574 		if (ffs_setup_state_clear_cancelled(ffs) ==
575 		    FFS_SETUP_CANCELLED) {
576 			ret = -EIDRM;
577 			break;
578 		}
579 
580 		/* unlocks spinlock */
581 		ret = __ffs_ep0_queue_wait(ffs, data, len);
582 		if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
583 			ret = -EFAULT;
584 		goto done_mutex;
585 
586 	default:
587 		ret = -EBADFD;
588 		break;
589 	}
590 
591 	spin_unlock_irq(&ffs->ev.waitq.lock);
592 done_mutex:
593 	mutex_unlock(&ffs->mutex);
594 	kfree(data);
595 	return ret;
596 }
597 
598 static int ffs_ep0_open(struct inode *inode, struct file *file)
599 {
600 	struct ffs_data *ffs = inode->i_private;
601 
602 	ENTER();
603 
604 	if (unlikely(ffs->state == FFS_CLOSING))
605 		return -EBUSY;
606 
607 	file->private_data = ffs;
608 	ffs_data_opened(ffs);
609 
610 	return 0;
611 }
612 
613 static int ffs_ep0_release(struct inode *inode, struct file *file)
614 {
615 	struct ffs_data *ffs = file->private_data;
616 
617 	ENTER();
618 
619 	ffs_data_closed(ffs);
620 
621 	return 0;
622 }
623 
624 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
625 {
626 	struct ffs_data *ffs = file->private_data;
627 	struct usb_gadget *gadget = ffs->gadget;
628 	long ret;
629 
630 	ENTER();
631 
632 	if (code == FUNCTIONFS_INTERFACE_REVMAP) {
633 		struct ffs_function *func = ffs->func;
634 		ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
635 	} else if (gadget && gadget->ops->ioctl) {
636 		ret = gadget->ops->ioctl(gadget, code, value);
637 	} else {
638 		ret = -ENOTTY;
639 	}
640 
641 	return ret;
642 }
643 
644 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
645 {
646 	struct ffs_data *ffs = file->private_data;
647 	__poll_t mask = EPOLLWRNORM;
648 	int ret;
649 
650 	poll_wait(file, &ffs->ev.waitq, wait);
651 
652 	ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
653 	if (unlikely(ret < 0))
654 		return mask;
655 
656 	switch (ffs->state) {
657 	case FFS_READ_DESCRIPTORS:
658 	case FFS_READ_STRINGS:
659 		mask |= EPOLLOUT;
660 		break;
661 
662 	case FFS_ACTIVE:
663 		switch (ffs->setup_state) {
664 		case FFS_NO_SETUP:
665 			if (ffs->ev.count)
666 				mask |= EPOLLIN;
667 			break;
668 
669 		case FFS_SETUP_PENDING:
670 		case FFS_SETUP_CANCELLED:
671 			mask |= (EPOLLIN | EPOLLOUT);
672 			break;
673 		}
674 	case FFS_CLOSING:
675 		break;
676 	case FFS_DEACTIVATED:
677 		break;
678 	}
679 
680 	mutex_unlock(&ffs->mutex);
681 
682 	return mask;
683 }
684 
685 static const struct file_operations ffs_ep0_operations = {
686 	.llseek =	no_llseek,
687 
688 	.open =		ffs_ep0_open,
689 	.write =	ffs_ep0_write,
690 	.read =		ffs_ep0_read,
691 	.release =	ffs_ep0_release,
692 	.unlocked_ioctl =	ffs_ep0_ioctl,
693 	.poll =		ffs_ep0_poll,
694 };
695 
696 
697 /* "Normal" endpoints operations ********************************************/
698 
699 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
700 {
701 	ENTER();
702 	if (likely(req->context)) {
703 		struct ffs_ep *ep = _ep->driver_data;
704 		ep->status = req->status ? req->status : req->actual;
705 		complete(req->context);
706 	}
707 }
708 
709 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
710 {
711 	ssize_t ret = copy_to_iter(data, data_len, iter);
712 	if (likely(ret == data_len))
713 		return ret;
714 
715 	if (unlikely(iov_iter_count(iter)))
716 		return -EFAULT;
717 
718 	/*
719 	 * Dear user space developer!
720 	 *
721 	 * TL;DR: To stop getting below error message in your kernel log, change
722 	 * user space code using functionfs to align read buffers to a max
723 	 * packet size.
724 	 *
725 	 * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
726 	 * packet size.  When unaligned buffer is passed to functionfs, it
727 	 * internally uses a larger, aligned buffer so that such UDCs are happy.
728 	 *
729 	 * Unfortunately, this means that host may send more data than was
730 	 * requested in read(2) system call.  f_fs doesn’t know what to do with
731 	 * that excess data so it simply drops it.
732 	 *
733 	 * Was the buffer aligned in the first place, no such problem would
734 	 * happen.
735 	 *
736 	 * Data may be dropped only in AIO reads.  Synchronous reads are handled
737 	 * by splitting a request into multiple parts.  This splitting may still
738 	 * be a problem though so it’s likely best to align the buffer
739 	 * regardless of it being AIO or not..
740 	 *
741 	 * This only affects OUT endpoints, i.e. reading data with a read(2),
742 	 * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
743 	 * affected.
744 	 */
745 	pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
746 	       "Align read buffer size to max packet size to avoid the problem.\n",
747 	       data_len, ret);
748 
749 	return ret;
750 }
751 
752 static void ffs_user_copy_worker(struct work_struct *work)
753 {
754 	struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
755 						   work);
756 	int ret = io_data->req->status ? io_data->req->status :
757 					 io_data->req->actual;
758 	bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
759 
760 	if (io_data->read && ret > 0) {
761 		mm_segment_t oldfs = get_fs();
762 
763 		set_fs(USER_DS);
764 		use_mm(io_data->mm);
765 		ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
766 		unuse_mm(io_data->mm);
767 		set_fs(oldfs);
768 	}
769 
770 	io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
771 
772 	if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
773 		eventfd_signal(io_data->ffs->ffs_eventfd, 1);
774 
775 	usb_ep_free_request(io_data->ep, io_data->req);
776 
777 	if (io_data->read)
778 		kfree(io_data->to_free);
779 	kfree(io_data->buf);
780 	kfree(io_data);
781 }
782 
783 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
784 					 struct usb_request *req)
785 {
786 	struct ffs_io_data *io_data = req->context;
787 	struct ffs_data *ffs = io_data->ffs;
788 
789 	ENTER();
790 
791 	INIT_WORK(&io_data->work, ffs_user_copy_worker);
792 	queue_work(ffs->io_completion_wq, &io_data->work);
793 }
794 
795 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
796 {
797 	/*
798 	 * See comment in struct ffs_epfile for full read_buffer pointer
799 	 * synchronisation story.
800 	 */
801 	struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
802 	if (buf && buf != READ_BUFFER_DROP)
803 		kfree(buf);
804 }
805 
806 /* Assumes epfile->mutex is held. */
807 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
808 					  struct iov_iter *iter)
809 {
810 	/*
811 	 * Null out epfile->read_buffer so ffs_func_eps_disable does not free
812 	 * the buffer while we are using it.  See comment in struct ffs_epfile
813 	 * for full read_buffer pointer synchronisation story.
814 	 */
815 	struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
816 	ssize_t ret;
817 	if (!buf || buf == READ_BUFFER_DROP)
818 		return 0;
819 
820 	ret = copy_to_iter(buf->data, buf->length, iter);
821 	if (buf->length == ret) {
822 		kfree(buf);
823 		return ret;
824 	}
825 
826 	if (unlikely(iov_iter_count(iter))) {
827 		ret = -EFAULT;
828 	} else {
829 		buf->length -= ret;
830 		buf->data += ret;
831 	}
832 
833 	if (cmpxchg(&epfile->read_buffer, NULL, buf))
834 		kfree(buf);
835 
836 	return ret;
837 }
838 
839 /* Assumes epfile->mutex is held. */
840 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
841 				      void *data, int data_len,
842 				      struct iov_iter *iter)
843 {
844 	struct ffs_buffer *buf;
845 
846 	ssize_t ret = copy_to_iter(data, data_len, iter);
847 	if (likely(data_len == ret))
848 		return ret;
849 
850 	if (unlikely(iov_iter_count(iter)))
851 		return -EFAULT;
852 
853 	/* See ffs_copy_to_iter for more context. */
854 	pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
855 		data_len, ret);
856 
857 	data_len -= ret;
858 	buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
859 	if (!buf)
860 		return -ENOMEM;
861 	buf->length = data_len;
862 	buf->data = buf->storage;
863 	memcpy(buf->storage, data + ret, data_len);
864 
865 	/*
866 	 * At this point read_buffer is NULL or READ_BUFFER_DROP (if
867 	 * ffs_func_eps_disable has been called in the meanwhile).  See comment
868 	 * in struct ffs_epfile for full read_buffer pointer synchronisation
869 	 * story.
870 	 */
871 	if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
872 		kfree(buf);
873 
874 	return ret;
875 }
876 
877 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
878 {
879 	struct ffs_epfile *epfile = file->private_data;
880 	struct usb_request *req;
881 	struct ffs_ep *ep;
882 	char *data = NULL;
883 	ssize_t ret, data_len = -EINVAL;
884 	int halt;
885 
886 	/* Are we still active? */
887 	if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
888 		return -ENODEV;
889 
890 	/* Wait for endpoint to be enabled */
891 	ep = epfile->ep;
892 	if (!ep) {
893 		if (file->f_flags & O_NONBLOCK)
894 			return -EAGAIN;
895 
896 		ret = wait_event_interruptible(
897 				epfile->ffs->wait, (ep = epfile->ep));
898 		if (ret)
899 			return -EINTR;
900 	}
901 
902 	/* Do we halt? */
903 	halt = (!io_data->read == !epfile->in);
904 	if (halt && epfile->isoc)
905 		return -EINVAL;
906 
907 	/* We will be using request and read_buffer */
908 	ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
909 	if (unlikely(ret))
910 		goto error;
911 
912 	/* Allocate & copy */
913 	if (!halt) {
914 		struct usb_gadget *gadget;
915 
916 		/*
917 		 * Do we have buffered data from previous partial read?  Check
918 		 * that for synchronous case only because we do not have
919 		 * facility to ‘wake up’ a pending asynchronous read and push
920 		 * buffered data to it which we would need to make things behave
921 		 * consistently.
922 		 */
923 		if (!io_data->aio && io_data->read) {
924 			ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
925 			if (ret)
926 				goto error_mutex;
927 		}
928 
929 		/*
930 		 * if we _do_ wait above, the epfile->ffs->gadget might be NULL
931 		 * before the waiting completes, so do not assign to 'gadget'
932 		 * earlier
933 		 */
934 		gadget = epfile->ffs->gadget;
935 
936 		spin_lock_irq(&epfile->ffs->eps_lock);
937 		/* In the meantime, endpoint got disabled or changed. */
938 		if (epfile->ep != ep) {
939 			ret = -ESHUTDOWN;
940 			goto error_lock;
941 		}
942 		data_len = iov_iter_count(&io_data->data);
943 		/*
944 		 * Controller may require buffer size to be aligned to
945 		 * maxpacketsize of an out endpoint.
946 		 */
947 		if (io_data->read)
948 			data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
949 		spin_unlock_irq(&epfile->ffs->eps_lock);
950 
951 		data = kmalloc(data_len, GFP_KERNEL);
952 		if (unlikely(!data)) {
953 			ret = -ENOMEM;
954 			goto error_mutex;
955 		}
956 		if (!io_data->read &&
957 		    !copy_from_iter_full(data, data_len, &io_data->data)) {
958 			ret = -EFAULT;
959 			goto error_mutex;
960 		}
961 	}
962 
963 	spin_lock_irq(&epfile->ffs->eps_lock);
964 
965 	if (epfile->ep != ep) {
966 		/* In the meantime, endpoint got disabled or changed. */
967 		ret = -ESHUTDOWN;
968 	} else if (halt) {
969 		ret = usb_ep_set_halt(ep->ep);
970 		if (!ret)
971 			ret = -EBADMSG;
972 	} else if (unlikely(data_len == -EINVAL)) {
973 		/*
974 		 * Sanity Check: even though data_len can't be used
975 		 * uninitialized at the time I write this comment, some
976 		 * compilers complain about this situation.
977 		 * In order to keep the code clean from warnings, data_len is
978 		 * being initialized to -EINVAL during its declaration, which
979 		 * means we can't rely on compiler anymore to warn no future
980 		 * changes won't result in data_len being used uninitialized.
981 		 * For such reason, we're adding this redundant sanity check
982 		 * here.
983 		 */
984 		WARN(1, "%s: data_len == -EINVAL\n", __func__);
985 		ret = -EINVAL;
986 	} else if (!io_data->aio) {
987 		DECLARE_COMPLETION_ONSTACK(done);
988 		bool interrupted = false;
989 
990 		req = ep->req;
991 		req->buf      = data;
992 		req->length   = data_len;
993 
994 		req->context  = &done;
995 		req->complete = ffs_epfile_io_complete;
996 
997 		ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
998 		if (unlikely(ret < 0))
999 			goto error_lock;
1000 
1001 		spin_unlock_irq(&epfile->ffs->eps_lock);
1002 
1003 		if (unlikely(wait_for_completion_interruptible(&done))) {
1004 			/*
1005 			 * To avoid race condition with ffs_epfile_io_complete,
1006 			 * dequeue the request first then check
1007 			 * status. usb_ep_dequeue API should guarantee no race
1008 			 * condition with req->complete callback.
1009 			 */
1010 			usb_ep_dequeue(ep->ep, req);
1011 			interrupted = ep->status < 0;
1012 		}
1013 
1014 		if (interrupted)
1015 			ret = -EINTR;
1016 		else if (io_data->read && ep->status > 0)
1017 			ret = __ffs_epfile_read_data(epfile, data, ep->status,
1018 						     &io_data->data);
1019 		else
1020 			ret = ep->status;
1021 		goto error_mutex;
1022 	} else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1023 		ret = -ENOMEM;
1024 	} else {
1025 		req->buf      = data;
1026 		req->length   = data_len;
1027 
1028 		io_data->buf = data;
1029 		io_data->ep = ep->ep;
1030 		io_data->req = req;
1031 		io_data->ffs = epfile->ffs;
1032 
1033 		req->context  = io_data;
1034 		req->complete = ffs_epfile_async_io_complete;
1035 
1036 		ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1037 		if (unlikely(ret)) {
1038 			usb_ep_free_request(ep->ep, req);
1039 			goto error_lock;
1040 		}
1041 
1042 		ret = -EIOCBQUEUED;
1043 		/*
1044 		 * Do not kfree the buffer in this function.  It will be freed
1045 		 * by ffs_user_copy_worker.
1046 		 */
1047 		data = NULL;
1048 	}
1049 
1050 error_lock:
1051 	spin_unlock_irq(&epfile->ffs->eps_lock);
1052 error_mutex:
1053 	mutex_unlock(&epfile->mutex);
1054 error:
1055 	kfree(data);
1056 	return ret;
1057 }
1058 
1059 static int
1060 ffs_epfile_open(struct inode *inode, struct file *file)
1061 {
1062 	struct ffs_epfile *epfile = inode->i_private;
1063 
1064 	ENTER();
1065 
1066 	if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1067 		return -ENODEV;
1068 
1069 	file->private_data = epfile;
1070 	ffs_data_opened(epfile->ffs);
1071 
1072 	return 0;
1073 }
1074 
1075 static int ffs_aio_cancel(struct kiocb *kiocb)
1076 {
1077 	struct ffs_io_data *io_data = kiocb->private;
1078 	struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1079 	int value;
1080 
1081 	ENTER();
1082 
1083 	spin_lock_irq(&epfile->ffs->eps_lock);
1084 
1085 	if (likely(io_data && io_data->ep && io_data->req))
1086 		value = usb_ep_dequeue(io_data->ep, io_data->req);
1087 	else
1088 		value = -EINVAL;
1089 
1090 	spin_unlock_irq(&epfile->ffs->eps_lock);
1091 
1092 	return value;
1093 }
1094 
1095 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1096 {
1097 	struct ffs_io_data io_data, *p = &io_data;
1098 	ssize_t res;
1099 
1100 	ENTER();
1101 
1102 	if (!is_sync_kiocb(kiocb)) {
1103 		p = kmalloc(sizeof(io_data), GFP_KERNEL);
1104 		if (unlikely(!p))
1105 			return -ENOMEM;
1106 		p->aio = true;
1107 	} else {
1108 		p->aio = false;
1109 	}
1110 
1111 	p->read = false;
1112 	p->kiocb = kiocb;
1113 	p->data = *from;
1114 	p->mm = current->mm;
1115 
1116 	kiocb->private = p;
1117 
1118 	if (p->aio)
1119 		kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1120 
1121 	res = ffs_epfile_io(kiocb->ki_filp, p);
1122 	if (res == -EIOCBQUEUED)
1123 		return res;
1124 	if (p->aio)
1125 		kfree(p);
1126 	else
1127 		*from = p->data;
1128 	return res;
1129 }
1130 
1131 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1132 {
1133 	struct ffs_io_data io_data, *p = &io_data;
1134 	ssize_t res;
1135 
1136 	ENTER();
1137 
1138 	if (!is_sync_kiocb(kiocb)) {
1139 		p = kmalloc(sizeof(io_data), GFP_KERNEL);
1140 		if (unlikely(!p))
1141 			return -ENOMEM;
1142 		p->aio = true;
1143 	} else {
1144 		p->aio = false;
1145 	}
1146 
1147 	p->read = true;
1148 	p->kiocb = kiocb;
1149 	if (p->aio) {
1150 		p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1151 		if (!p->to_free) {
1152 			kfree(p);
1153 			return -ENOMEM;
1154 		}
1155 	} else {
1156 		p->data = *to;
1157 		p->to_free = NULL;
1158 	}
1159 	p->mm = current->mm;
1160 
1161 	kiocb->private = p;
1162 
1163 	if (p->aio)
1164 		kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1165 
1166 	res = ffs_epfile_io(kiocb->ki_filp, p);
1167 	if (res == -EIOCBQUEUED)
1168 		return res;
1169 
1170 	if (p->aio) {
1171 		kfree(p->to_free);
1172 		kfree(p);
1173 	} else {
1174 		*to = p->data;
1175 	}
1176 	return res;
1177 }
1178 
1179 static int
1180 ffs_epfile_release(struct inode *inode, struct file *file)
1181 {
1182 	struct ffs_epfile *epfile = inode->i_private;
1183 
1184 	ENTER();
1185 
1186 	__ffs_epfile_read_buffer_free(epfile);
1187 	ffs_data_closed(epfile->ffs);
1188 
1189 	return 0;
1190 }
1191 
1192 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1193 			     unsigned long value)
1194 {
1195 	struct ffs_epfile *epfile = file->private_data;
1196 	struct ffs_ep *ep;
1197 	int ret;
1198 
1199 	ENTER();
1200 
1201 	if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1202 		return -ENODEV;
1203 
1204 	/* Wait for endpoint to be enabled */
1205 	ep = epfile->ep;
1206 	if (!ep) {
1207 		if (file->f_flags & O_NONBLOCK)
1208 			return -EAGAIN;
1209 
1210 		ret = wait_event_interruptible(
1211 				epfile->ffs->wait, (ep = epfile->ep));
1212 		if (ret)
1213 			return -EINTR;
1214 	}
1215 
1216 	spin_lock_irq(&epfile->ffs->eps_lock);
1217 
1218 	/* In the meantime, endpoint got disabled or changed. */
1219 	if (epfile->ep != ep) {
1220 		spin_unlock_irq(&epfile->ffs->eps_lock);
1221 		return -ESHUTDOWN;
1222 	}
1223 
1224 	switch (code) {
1225 	case FUNCTIONFS_FIFO_STATUS:
1226 		ret = usb_ep_fifo_status(epfile->ep->ep);
1227 		break;
1228 	case FUNCTIONFS_FIFO_FLUSH:
1229 		usb_ep_fifo_flush(epfile->ep->ep);
1230 		ret = 0;
1231 		break;
1232 	case FUNCTIONFS_CLEAR_HALT:
1233 		ret = usb_ep_clear_halt(epfile->ep->ep);
1234 		break;
1235 	case FUNCTIONFS_ENDPOINT_REVMAP:
1236 		ret = epfile->ep->num;
1237 		break;
1238 	case FUNCTIONFS_ENDPOINT_DESC:
1239 	{
1240 		int desc_idx;
1241 		struct usb_endpoint_descriptor *desc;
1242 
1243 		switch (epfile->ffs->gadget->speed) {
1244 		case USB_SPEED_SUPER:
1245 			desc_idx = 2;
1246 			break;
1247 		case USB_SPEED_HIGH:
1248 			desc_idx = 1;
1249 			break;
1250 		default:
1251 			desc_idx = 0;
1252 		}
1253 		desc = epfile->ep->descs[desc_idx];
1254 
1255 		spin_unlock_irq(&epfile->ffs->eps_lock);
1256 		ret = copy_to_user((void __user *)value, desc, desc->bLength);
1257 		if (ret)
1258 			ret = -EFAULT;
1259 		return ret;
1260 	}
1261 	default:
1262 		ret = -ENOTTY;
1263 	}
1264 	spin_unlock_irq(&epfile->ffs->eps_lock);
1265 
1266 	return ret;
1267 }
1268 
1269 #ifdef CONFIG_COMPAT
1270 static long ffs_epfile_compat_ioctl(struct file *file, unsigned code,
1271 		unsigned long value)
1272 {
1273 	return ffs_epfile_ioctl(file, code, value);
1274 }
1275 #endif
1276 
1277 static const struct file_operations ffs_epfile_operations = {
1278 	.llseek =	no_llseek,
1279 
1280 	.open =		ffs_epfile_open,
1281 	.write_iter =	ffs_epfile_write_iter,
1282 	.read_iter =	ffs_epfile_read_iter,
1283 	.release =	ffs_epfile_release,
1284 	.unlocked_ioctl =	ffs_epfile_ioctl,
1285 #ifdef CONFIG_COMPAT
1286 	.compat_ioctl = ffs_epfile_compat_ioctl,
1287 #endif
1288 };
1289 
1290 
1291 /* File system and super block operations ***********************************/
1292 
1293 /*
1294  * Mounting the file system creates a controller file, used first for
1295  * function configuration then later for event monitoring.
1296  */
1297 
1298 static struct inode *__must_check
1299 ffs_sb_make_inode(struct super_block *sb, void *data,
1300 		  const struct file_operations *fops,
1301 		  const struct inode_operations *iops,
1302 		  struct ffs_file_perms *perms)
1303 {
1304 	struct inode *inode;
1305 
1306 	ENTER();
1307 
1308 	inode = new_inode(sb);
1309 
1310 	if (likely(inode)) {
1311 		struct timespec64 ts = current_time(inode);
1312 
1313 		inode->i_ino	 = get_next_ino();
1314 		inode->i_mode    = perms->mode;
1315 		inode->i_uid     = perms->uid;
1316 		inode->i_gid     = perms->gid;
1317 		inode->i_atime   = ts;
1318 		inode->i_mtime   = ts;
1319 		inode->i_ctime   = ts;
1320 		inode->i_private = data;
1321 		if (fops)
1322 			inode->i_fop = fops;
1323 		if (iops)
1324 			inode->i_op  = iops;
1325 	}
1326 
1327 	return inode;
1328 }
1329 
1330 /* Create "regular" file */
1331 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1332 					const char *name, void *data,
1333 					const struct file_operations *fops)
1334 {
1335 	struct ffs_data	*ffs = sb->s_fs_info;
1336 	struct dentry	*dentry;
1337 	struct inode	*inode;
1338 
1339 	ENTER();
1340 
1341 	dentry = d_alloc_name(sb->s_root, name);
1342 	if (unlikely(!dentry))
1343 		return NULL;
1344 
1345 	inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1346 	if (unlikely(!inode)) {
1347 		dput(dentry);
1348 		return NULL;
1349 	}
1350 
1351 	d_add(dentry, inode);
1352 	return dentry;
1353 }
1354 
1355 /* Super block */
1356 static const struct super_operations ffs_sb_operations = {
1357 	.statfs =	simple_statfs,
1358 	.drop_inode =	generic_delete_inode,
1359 };
1360 
1361 struct ffs_sb_fill_data {
1362 	struct ffs_file_perms perms;
1363 	umode_t root_mode;
1364 	const char *dev_name;
1365 	bool no_disconnect;
1366 	struct ffs_data *ffs_data;
1367 };
1368 
1369 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1370 {
1371 	struct ffs_sb_fill_data *data = _data;
1372 	struct inode	*inode;
1373 	struct ffs_data	*ffs = data->ffs_data;
1374 
1375 	ENTER();
1376 
1377 	ffs->sb              = sb;
1378 	data->ffs_data       = NULL;
1379 	sb->s_fs_info        = ffs;
1380 	sb->s_blocksize      = PAGE_SIZE;
1381 	sb->s_blocksize_bits = PAGE_SHIFT;
1382 	sb->s_magic          = FUNCTIONFS_MAGIC;
1383 	sb->s_op             = &ffs_sb_operations;
1384 	sb->s_time_gran      = 1;
1385 
1386 	/* Root inode */
1387 	data->perms.mode = data->root_mode;
1388 	inode = ffs_sb_make_inode(sb, NULL,
1389 				  &simple_dir_operations,
1390 				  &simple_dir_inode_operations,
1391 				  &data->perms);
1392 	sb->s_root = d_make_root(inode);
1393 	if (unlikely(!sb->s_root))
1394 		return -ENOMEM;
1395 
1396 	/* EP0 file */
1397 	if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1398 					 &ffs_ep0_operations)))
1399 		return -ENOMEM;
1400 
1401 	return 0;
1402 }
1403 
1404 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1405 {
1406 	ENTER();
1407 
1408 	if (!opts || !*opts)
1409 		return 0;
1410 
1411 	for (;;) {
1412 		unsigned long value;
1413 		char *eq, *comma;
1414 
1415 		/* Option limit */
1416 		comma = strchr(opts, ',');
1417 		if (comma)
1418 			*comma = 0;
1419 
1420 		/* Value limit */
1421 		eq = strchr(opts, '=');
1422 		if (unlikely(!eq)) {
1423 			pr_err("'=' missing in %s\n", opts);
1424 			return -EINVAL;
1425 		}
1426 		*eq = 0;
1427 
1428 		/* Parse value */
1429 		if (kstrtoul(eq + 1, 0, &value)) {
1430 			pr_err("%s: invalid value: %s\n", opts, eq + 1);
1431 			return -EINVAL;
1432 		}
1433 
1434 		/* Interpret option */
1435 		switch (eq - opts) {
1436 		case 13:
1437 			if (!memcmp(opts, "no_disconnect", 13))
1438 				data->no_disconnect = !!value;
1439 			else
1440 				goto invalid;
1441 			break;
1442 		case 5:
1443 			if (!memcmp(opts, "rmode", 5))
1444 				data->root_mode  = (value & 0555) | S_IFDIR;
1445 			else if (!memcmp(opts, "fmode", 5))
1446 				data->perms.mode = (value & 0666) | S_IFREG;
1447 			else
1448 				goto invalid;
1449 			break;
1450 
1451 		case 4:
1452 			if (!memcmp(opts, "mode", 4)) {
1453 				data->root_mode  = (value & 0555) | S_IFDIR;
1454 				data->perms.mode = (value & 0666) | S_IFREG;
1455 			} else {
1456 				goto invalid;
1457 			}
1458 			break;
1459 
1460 		case 3:
1461 			if (!memcmp(opts, "uid", 3)) {
1462 				data->perms.uid = make_kuid(current_user_ns(), value);
1463 				if (!uid_valid(data->perms.uid)) {
1464 					pr_err("%s: unmapped value: %lu\n", opts, value);
1465 					return -EINVAL;
1466 				}
1467 			} else if (!memcmp(opts, "gid", 3)) {
1468 				data->perms.gid = make_kgid(current_user_ns(), value);
1469 				if (!gid_valid(data->perms.gid)) {
1470 					pr_err("%s: unmapped value: %lu\n", opts, value);
1471 					return -EINVAL;
1472 				}
1473 			} else {
1474 				goto invalid;
1475 			}
1476 			break;
1477 
1478 		default:
1479 invalid:
1480 			pr_err("%s: invalid option\n", opts);
1481 			return -EINVAL;
1482 		}
1483 
1484 		/* Next iteration */
1485 		if (!comma)
1486 			break;
1487 		opts = comma + 1;
1488 	}
1489 
1490 	return 0;
1491 }
1492 
1493 /* "mount -t functionfs dev_name /dev/function" ends up here */
1494 
1495 static struct dentry *
1496 ffs_fs_mount(struct file_system_type *t, int flags,
1497 	      const char *dev_name, void *opts)
1498 {
1499 	struct ffs_sb_fill_data data = {
1500 		.perms = {
1501 			.mode = S_IFREG | 0600,
1502 			.uid = GLOBAL_ROOT_UID,
1503 			.gid = GLOBAL_ROOT_GID,
1504 		},
1505 		.root_mode = S_IFDIR | 0500,
1506 		.no_disconnect = false,
1507 	};
1508 	struct dentry *rv;
1509 	int ret;
1510 	void *ffs_dev;
1511 	struct ffs_data	*ffs;
1512 
1513 	ENTER();
1514 
1515 	ret = ffs_fs_parse_opts(&data, opts);
1516 	if (unlikely(ret < 0))
1517 		return ERR_PTR(ret);
1518 
1519 	ffs = ffs_data_new(dev_name);
1520 	if (unlikely(!ffs))
1521 		return ERR_PTR(-ENOMEM);
1522 	ffs->file_perms = data.perms;
1523 	ffs->no_disconnect = data.no_disconnect;
1524 
1525 	ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1526 	if (unlikely(!ffs->dev_name)) {
1527 		ffs_data_put(ffs);
1528 		return ERR_PTR(-ENOMEM);
1529 	}
1530 
1531 	ffs_dev = ffs_acquire_dev(dev_name);
1532 	if (IS_ERR(ffs_dev)) {
1533 		ffs_data_put(ffs);
1534 		return ERR_CAST(ffs_dev);
1535 	}
1536 	ffs->private_data = ffs_dev;
1537 	data.ffs_data = ffs;
1538 
1539 	rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1540 	if (IS_ERR(rv) && data.ffs_data) {
1541 		ffs_release_dev(data.ffs_data);
1542 		ffs_data_put(data.ffs_data);
1543 	}
1544 	return rv;
1545 }
1546 
1547 static void
1548 ffs_fs_kill_sb(struct super_block *sb)
1549 {
1550 	ENTER();
1551 
1552 	kill_litter_super(sb);
1553 	if (sb->s_fs_info) {
1554 		ffs_release_dev(sb->s_fs_info);
1555 		ffs_data_closed(sb->s_fs_info);
1556 	}
1557 }
1558 
1559 static struct file_system_type ffs_fs_type = {
1560 	.owner		= THIS_MODULE,
1561 	.name		= "functionfs",
1562 	.mount		= ffs_fs_mount,
1563 	.kill_sb	= ffs_fs_kill_sb,
1564 };
1565 MODULE_ALIAS_FS("functionfs");
1566 
1567 
1568 /* Driver's main init/cleanup functions *************************************/
1569 
1570 static int functionfs_init(void)
1571 {
1572 	int ret;
1573 
1574 	ENTER();
1575 
1576 	ret = register_filesystem(&ffs_fs_type);
1577 	if (likely(!ret))
1578 		pr_info("file system registered\n");
1579 	else
1580 		pr_err("failed registering file system (%d)\n", ret);
1581 
1582 	return ret;
1583 }
1584 
1585 static void functionfs_cleanup(void)
1586 {
1587 	ENTER();
1588 
1589 	pr_info("unloading\n");
1590 	unregister_filesystem(&ffs_fs_type);
1591 }
1592 
1593 
1594 /* ffs_data and ffs_function construction and destruction code **************/
1595 
1596 static void ffs_data_clear(struct ffs_data *ffs);
1597 static void ffs_data_reset(struct ffs_data *ffs);
1598 
1599 static void ffs_data_get(struct ffs_data *ffs)
1600 {
1601 	ENTER();
1602 
1603 	refcount_inc(&ffs->ref);
1604 }
1605 
1606 static void ffs_data_opened(struct ffs_data *ffs)
1607 {
1608 	ENTER();
1609 
1610 	refcount_inc(&ffs->ref);
1611 	if (atomic_add_return(1, &ffs->opened) == 1 &&
1612 			ffs->state == FFS_DEACTIVATED) {
1613 		ffs->state = FFS_CLOSING;
1614 		ffs_data_reset(ffs);
1615 	}
1616 }
1617 
1618 static void ffs_data_put(struct ffs_data *ffs)
1619 {
1620 	ENTER();
1621 
1622 	if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1623 		pr_info("%s(): freeing\n", __func__);
1624 		ffs_data_clear(ffs);
1625 		BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1626 		       waitqueue_active(&ffs->ep0req_completion.wait) ||
1627 		       waitqueue_active(&ffs->wait));
1628 		destroy_workqueue(ffs->io_completion_wq);
1629 		kfree(ffs->dev_name);
1630 		kfree(ffs);
1631 	}
1632 }
1633 
1634 static void ffs_data_closed(struct ffs_data *ffs)
1635 {
1636 	ENTER();
1637 
1638 	if (atomic_dec_and_test(&ffs->opened)) {
1639 		if (ffs->no_disconnect) {
1640 			ffs->state = FFS_DEACTIVATED;
1641 			if (ffs->epfiles) {
1642 				ffs_epfiles_destroy(ffs->epfiles,
1643 						   ffs->eps_count);
1644 				ffs->epfiles = NULL;
1645 			}
1646 			if (ffs->setup_state == FFS_SETUP_PENDING)
1647 				__ffs_ep0_stall(ffs);
1648 		} else {
1649 			ffs->state = FFS_CLOSING;
1650 			ffs_data_reset(ffs);
1651 		}
1652 	}
1653 	if (atomic_read(&ffs->opened) < 0) {
1654 		ffs->state = FFS_CLOSING;
1655 		ffs_data_reset(ffs);
1656 	}
1657 
1658 	ffs_data_put(ffs);
1659 }
1660 
1661 static struct ffs_data *ffs_data_new(const char *dev_name)
1662 {
1663 	struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1664 	if (unlikely(!ffs))
1665 		return NULL;
1666 
1667 	ENTER();
1668 
1669 	ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1670 	if (!ffs->io_completion_wq) {
1671 		kfree(ffs);
1672 		return NULL;
1673 	}
1674 
1675 	refcount_set(&ffs->ref, 1);
1676 	atomic_set(&ffs->opened, 0);
1677 	ffs->state = FFS_READ_DESCRIPTORS;
1678 	mutex_init(&ffs->mutex);
1679 	spin_lock_init(&ffs->eps_lock);
1680 	init_waitqueue_head(&ffs->ev.waitq);
1681 	init_waitqueue_head(&ffs->wait);
1682 	init_completion(&ffs->ep0req_completion);
1683 
1684 	/* XXX REVISIT need to update it in some places, or do we? */
1685 	ffs->ev.can_stall = 1;
1686 
1687 	return ffs;
1688 }
1689 
1690 static void ffs_data_clear(struct ffs_data *ffs)
1691 {
1692 	ENTER();
1693 
1694 	ffs_closed(ffs);
1695 
1696 	BUG_ON(ffs->gadget);
1697 
1698 	if (ffs->epfiles)
1699 		ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1700 
1701 	if (ffs->ffs_eventfd)
1702 		eventfd_ctx_put(ffs->ffs_eventfd);
1703 
1704 	kfree(ffs->raw_descs_data);
1705 	kfree(ffs->raw_strings);
1706 	kfree(ffs->stringtabs);
1707 }
1708 
1709 static void ffs_data_reset(struct ffs_data *ffs)
1710 {
1711 	ENTER();
1712 
1713 	ffs_data_clear(ffs);
1714 
1715 	ffs->epfiles = NULL;
1716 	ffs->raw_descs_data = NULL;
1717 	ffs->raw_descs = NULL;
1718 	ffs->raw_strings = NULL;
1719 	ffs->stringtabs = NULL;
1720 
1721 	ffs->raw_descs_length = 0;
1722 	ffs->fs_descs_count = 0;
1723 	ffs->hs_descs_count = 0;
1724 	ffs->ss_descs_count = 0;
1725 
1726 	ffs->strings_count = 0;
1727 	ffs->interfaces_count = 0;
1728 	ffs->eps_count = 0;
1729 
1730 	ffs->ev.count = 0;
1731 
1732 	ffs->state = FFS_READ_DESCRIPTORS;
1733 	ffs->setup_state = FFS_NO_SETUP;
1734 	ffs->flags = 0;
1735 }
1736 
1737 
1738 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1739 {
1740 	struct usb_gadget_strings **lang;
1741 	int first_id;
1742 
1743 	ENTER();
1744 
1745 	if (WARN_ON(ffs->state != FFS_ACTIVE
1746 		 || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1747 		return -EBADFD;
1748 
1749 	first_id = usb_string_ids_n(cdev, ffs->strings_count);
1750 	if (unlikely(first_id < 0))
1751 		return first_id;
1752 
1753 	ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1754 	if (unlikely(!ffs->ep0req))
1755 		return -ENOMEM;
1756 	ffs->ep0req->complete = ffs_ep0_complete;
1757 	ffs->ep0req->context = ffs;
1758 
1759 	lang = ffs->stringtabs;
1760 	if (lang) {
1761 		for (; *lang; ++lang) {
1762 			struct usb_string *str = (*lang)->strings;
1763 			int id = first_id;
1764 			for (; str->s; ++id, ++str)
1765 				str->id = id;
1766 		}
1767 	}
1768 
1769 	ffs->gadget = cdev->gadget;
1770 	ffs_data_get(ffs);
1771 	return 0;
1772 }
1773 
1774 static void functionfs_unbind(struct ffs_data *ffs)
1775 {
1776 	ENTER();
1777 
1778 	if (!WARN_ON(!ffs->gadget)) {
1779 		usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1780 		ffs->ep0req = NULL;
1781 		ffs->gadget = NULL;
1782 		clear_bit(FFS_FL_BOUND, &ffs->flags);
1783 		ffs_data_put(ffs);
1784 	}
1785 }
1786 
1787 static int ffs_epfiles_create(struct ffs_data *ffs)
1788 {
1789 	struct ffs_epfile *epfile, *epfiles;
1790 	unsigned i, count;
1791 
1792 	ENTER();
1793 
1794 	count = ffs->eps_count;
1795 	epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1796 	if (!epfiles)
1797 		return -ENOMEM;
1798 
1799 	epfile = epfiles;
1800 	for (i = 1; i <= count; ++i, ++epfile) {
1801 		epfile->ffs = ffs;
1802 		mutex_init(&epfile->mutex);
1803 		if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1804 			sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1805 		else
1806 			sprintf(epfile->name, "ep%u", i);
1807 		epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1808 						 epfile,
1809 						 &ffs_epfile_operations);
1810 		if (unlikely(!epfile->dentry)) {
1811 			ffs_epfiles_destroy(epfiles, i - 1);
1812 			return -ENOMEM;
1813 		}
1814 	}
1815 
1816 	ffs->epfiles = epfiles;
1817 	return 0;
1818 }
1819 
1820 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1821 {
1822 	struct ffs_epfile *epfile = epfiles;
1823 
1824 	ENTER();
1825 
1826 	for (; count; --count, ++epfile) {
1827 		BUG_ON(mutex_is_locked(&epfile->mutex));
1828 		if (epfile->dentry) {
1829 			d_delete(epfile->dentry);
1830 			dput(epfile->dentry);
1831 			epfile->dentry = NULL;
1832 		}
1833 	}
1834 
1835 	kfree(epfiles);
1836 }
1837 
1838 static void ffs_func_eps_disable(struct ffs_function *func)
1839 {
1840 	struct ffs_ep *ep         = func->eps;
1841 	struct ffs_epfile *epfile = func->ffs->epfiles;
1842 	unsigned count            = func->ffs->eps_count;
1843 	unsigned long flags;
1844 
1845 	spin_lock_irqsave(&func->ffs->eps_lock, flags);
1846 	while (count--) {
1847 		/* pending requests get nuked */
1848 		if (likely(ep->ep))
1849 			usb_ep_disable(ep->ep);
1850 		++ep;
1851 
1852 		if (epfile) {
1853 			epfile->ep = NULL;
1854 			__ffs_epfile_read_buffer_free(epfile);
1855 			++epfile;
1856 		}
1857 	}
1858 	spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1859 }
1860 
1861 static int ffs_func_eps_enable(struct ffs_function *func)
1862 {
1863 	struct ffs_data *ffs      = func->ffs;
1864 	struct ffs_ep *ep         = func->eps;
1865 	struct ffs_epfile *epfile = ffs->epfiles;
1866 	unsigned count            = ffs->eps_count;
1867 	unsigned long flags;
1868 	int ret = 0;
1869 
1870 	spin_lock_irqsave(&func->ffs->eps_lock, flags);
1871 	while(count--) {
1872 		ep->ep->driver_data = ep;
1873 
1874 		ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1875 		if (ret) {
1876 			pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1877 					__func__, ep->ep->name, ret);
1878 			break;
1879 		}
1880 
1881 		ret = usb_ep_enable(ep->ep);
1882 		if (likely(!ret)) {
1883 			epfile->ep = ep;
1884 			epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1885 			epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1886 		} else {
1887 			break;
1888 		}
1889 
1890 		++ep;
1891 		++epfile;
1892 	}
1893 
1894 	wake_up_interruptible(&ffs->wait);
1895 	spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1896 
1897 	return ret;
1898 }
1899 
1900 
1901 /* Parsing and building descriptors and strings *****************************/
1902 
1903 /*
1904  * This validates if data pointed by data is a valid USB descriptor as
1905  * well as record how many interfaces, endpoints and strings are
1906  * required by given configuration.  Returns address after the
1907  * descriptor or NULL if data is invalid.
1908  */
1909 
1910 enum ffs_entity_type {
1911 	FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1912 };
1913 
1914 enum ffs_os_desc_type {
1915 	FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1916 };
1917 
1918 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1919 				   u8 *valuep,
1920 				   struct usb_descriptor_header *desc,
1921 				   void *priv);
1922 
1923 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1924 				    struct usb_os_desc_header *h, void *data,
1925 				    unsigned len, void *priv);
1926 
1927 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1928 					   ffs_entity_callback entity,
1929 					   void *priv)
1930 {
1931 	struct usb_descriptor_header *_ds = (void *)data;
1932 	u8 length;
1933 	int ret;
1934 
1935 	ENTER();
1936 
1937 	/* At least two bytes are required: length and type */
1938 	if (len < 2) {
1939 		pr_vdebug("descriptor too short\n");
1940 		return -EINVAL;
1941 	}
1942 
1943 	/* If we have at least as many bytes as the descriptor takes? */
1944 	length = _ds->bLength;
1945 	if (len < length) {
1946 		pr_vdebug("descriptor longer then available data\n");
1947 		return -EINVAL;
1948 	}
1949 
1950 #define __entity_check_INTERFACE(val)  1
1951 #define __entity_check_STRING(val)     (val)
1952 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1953 #define __entity(type, val) do {					\
1954 		pr_vdebug("entity " #type "(%02x)\n", (val));		\
1955 		if (unlikely(!__entity_check_ ##type(val))) {		\
1956 			pr_vdebug("invalid entity's value\n");		\
1957 			return -EINVAL;					\
1958 		}							\
1959 		ret = entity(FFS_ ##type, &val, _ds, priv);		\
1960 		if (unlikely(ret < 0)) {				\
1961 			pr_debug("entity " #type "(%02x); ret = %d\n",	\
1962 				 (val), ret);				\
1963 			return ret;					\
1964 		}							\
1965 	} while (0)
1966 
1967 	/* Parse descriptor depending on type. */
1968 	switch (_ds->bDescriptorType) {
1969 	case USB_DT_DEVICE:
1970 	case USB_DT_CONFIG:
1971 	case USB_DT_STRING:
1972 	case USB_DT_DEVICE_QUALIFIER:
1973 		/* function can't have any of those */
1974 		pr_vdebug("descriptor reserved for gadget: %d\n",
1975 		      _ds->bDescriptorType);
1976 		return -EINVAL;
1977 
1978 	case USB_DT_INTERFACE: {
1979 		struct usb_interface_descriptor *ds = (void *)_ds;
1980 		pr_vdebug("interface descriptor\n");
1981 		if (length != sizeof *ds)
1982 			goto inv_length;
1983 
1984 		__entity(INTERFACE, ds->bInterfaceNumber);
1985 		if (ds->iInterface)
1986 			__entity(STRING, ds->iInterface);
1987 	}
1988 		break;
1989 
1990 	case USB_DT_ENDPOINT: {
1991 		struct usb_endpoint_descriptor *ds = (void *)_ds;
1992 		pr_vdebug("endpoint descriptor\n");
1993 		if (length != USB_DT_ENDPOINT_SIZE &&
1994 		    length != USB_DT_ENDPOINT_AUDIO_SIZE)
1995 			goto inv_length;
1996 		__entity(ENDPOINT, ds->bEndpointAddress);
1997 	}
1998 		break;
1999 
2000 	case HID_DT_HID:
2001 		pr_vdebug("hid descriptor\n");
2002 		if (length != sizeof(struct hid_descriptor))
2003 			goto inv_length;
2004 		break;
2005 
2006 	case USB_DT_OTG:
2007 		if (length != sizeof(struct usb_otg_descriptor))
2008 			goto inv_length;
2009 		break;
2010 
2011 	case USB_DT_INTERFACE_ASSOCIATION: {
2012 		struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2013 		pr_vdebug("interface association descriptor\n");
2014 		if (length != sizeof *ds)
2015 			goto inv_length;
2016 		if (ds->iFunction)
2017 			__entity(STRING, ds->iFunction);
2018 	}
2019 		break;
2020 
2021 	case USB_DT_SS_ENDPOINT_COMP:
2022 		pr_vdebug("EP SS companion descriptor\n");
2023 		if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2024 			goto inv_length;
2025 		break;
2026 
2027 	case USB_DT_OTHER_SPEED_CONFIG:
2028 	case USB_DT_INTERFACE_POWER:
2029 	case USB_DT_DEBUG:
2030 	case USB_DT_SECURITY:
2031 	case USB_DT_CS_RADIO_CONTROL:
2032 		/* TODO */
2033 		pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2034 		return -EINVAL;
2035 
2036 	default:
2037 		/* We should never be here */
2038 		pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2039 		return -EINVAL;
2040 
2041 inv_length:
2042 		pr_vdebug("invalid length: %d (descriptor %d)\n",
2043 			  _ds->bLength, _ds->bDescriptorType);
2044 		return -EINVAL;
2045 	}
2046 
2047 #undef __entity
2048 #undef __entity_check_DESCRIPTOR
2049 #undef __entity_check_INTERFACE
2050 #undef __entity_check_STRING
2051 #undef __entity_check_ENDPOINT
2052 
2053 	return length;
2054 }
2055 
2056 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2057 				     ffs_entity_callback entity, void *priv)
2058 {
2059 	const unsigned _len = len;
2060 	unsigned long num = 0;
2061 
2062 	ENTER();
2063 
2064 	for (;;) {
2065 		int ret;
2066 
2067 		if (num == count)
2068 			data = NULL;
2069 
2070 		/* Record "descriptor" entity */
2071 		ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2072 		if (unlikely(ret < 0)) {
2073 			pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2074 				 num, ret);
2075 			return ret;
2076 		}
2077 
2078 		if (!data)
2079 			return _len - len;
2080 
2081 		ret = ffs_do_single_desc(data, len, entity, priv);
2082 		if (unlikely(ret < 0)) {
2083 			pr_debug("%s returns %d\n", __func__, ret);
2084 			return ret;
2085 		}
2086 
2087 		len -= ret;
2088 		data += ret;
2089 		++num;
2090 	}
2091 }
2092 
2093 static int __ffs_data_do_entity(enum ffs_entity_type type,
2094 				u8 *valuep, struct usb_descriptor_header *desc,
2095 				void *priv)
2096 {
2097 	struct ffs_desc_helper *helper = priv;
2098 	struct usb_endpoint_descriptor *d;
2099 
2100 	ENTER();
2101 
2102 	switch (type) {
2103 	case FFS_DESCRIPTOR:
2104 		break;
2105 
2106 	case FFS_INTERFACE:
2107 		/*
2108 		 * Interfaces are indexed from zero so if we
2109 		 * encountered interface "n" then there are at least
2110 		 * "n+1" interfaces.
2111 		 */
2112 		if (*valuep >= helper->interfaces_count)
2113 			helper->interfaces_count = *valuep + 1;
2114 		break;
2115 
2116 	case FFS_STRING:
2117 		/*
2118 		 * Strings are indexed from 1 (0 is reserved
2119 		 * for languages list)
2120 		 */
2121 		if (*valuep > helper->ffs->strings_count)
2122 			helper->ffs->strings_count = *valuep;
2123 		break;
2124 
2125 	case FFS_ENDPOINT:
2126 		d = (void *)desc;
2127 		helper->eps_count++;
2128 		if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2129 			return -EINVAL;
2130 		/* Check if descriptors for any speed were already parsed */
2131 		if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2132 			helper->ffs->eps_addrmap[helper->eps_count] =
2133 				d->bEndpointAddress;
2134 		else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2135 				d->bEndpointAddress)
2136 			return -EINVAL;
2137 		break;
2138 	}
2139 
2140 	return 0;
2141 }
2142 
2143 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2144 				   struct usb_os_desc_header *desc)
2145 {
2146 	u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2147 	u16 w_index = le16_to_cpu(desc->wIndex);
2148 
2149 	if (bcd_version != 1) {
2150 		pr_vdebug("unsupported os descriptors version: %d",
2151 			  bcd_version);
2152 		return -EINVAL;
2153 	}
2154 	switch (w_index) {
2155 	case 0x4:
2156 		*next_type = FFS_OS_DESC_EXT_COMPAT;
2157 		break;
2158 	case 0x5:
2159 		*next_type = FFS_OS_DESC_EXT_PROP;
2160 		break;
2161 	default:
2162 		pr_vdebug("unsupported os descriptor type: %d", w_index);
2163 		return -EINVAL;
2164 	}
2165 
2166 	return sizeof(*desc);
2167 }
2168 
2169 /*
2170  * Process all extended compatibility/extended property descriptors
2171  * of a feature descriptor
2172  */
2173 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2174 					      enum ffs_os_desc_type type,
2175 					      u16 feature_count,
2176 					      ffs_os_desc_callback entity,
2177 					      void *priv,
2178 					      struct usb_os_desc_header *h)
2179 {
2180 	int ret;
2181 	const unsigned _len = len;
2182 
2183 	ENTER();
2184 
2185 	/* loop over all ext compat/ext prop descriptors */
2186 	while (feature_count--) {
2187 		ret = entity(type, h, data, len, priv);
2188 		if (unlikely(ret < 0)) {
2189 			pr_debug("bad OS descriptor, type: %d\n", type);
2190 			return ret;
2191 		}
2192 		data += ret;
2193 		len -= ret;
2194 	}
2195 	return _len - len;
2196 }
2197 
2198 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2199 static int __must_check ffs_do_os_descs(unsigned count,
2200 					char *data, unsigned len,
2201 					ffs_os_desc_callback entity, void *priv)
2202 {
2203 	const unsigned _len = len;
2204 	unsigned long num = 0;
2205 
2206 	ENTER();
2207 
2208 	for (num = 0; num < count; ++num) {
2209 		int ret;
2210 		enum ffs_os_desc_type type;
2211 		u16 feature_count;
2212 		struct usb_os_desc_header *desc = (void *)data;
2213 
2214 		if (len < sizeof(*desc))
2215 			return -EINVAL;
2216 
2217 		/*
2218 		 * Record "descriptor" entity.
2219 		 * Process dwLength, bcdVersion, wIndex, get b/wCount.
2220 		 * Move the data pointer to the beginning of extended
2221 		 * compatibilities proper or extended properties proper
2222 		 * portions of the data
2223 		 */
2224 		if (le32_to_cpu(desc->dwLength) > len)
2225 			return -EINVAL;
2226 
2227 		ret = __ffs_do_os_desc_header(&type, desc);
2228 		if (unlikely(ret < 0)) {
2229 			pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2230 				 num, ret);
2231 			return ret;
2232 		}
2233 		/*
2234 		 * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2235 		 */
2236 		feature_count = le16_to_cpu(desc->wCount);
2237 		if (type == FFS_OS_DESC_EXT_COMPAT &&
2238 		    (feature_count > 255 || desc->Reserved))
2239 				return -EINVAL;
2240 		len -= ret;
2241 		data += ret;
2242 
2243 		/*
2244 		 * Process all function/property descriptors
2245 		 * of this Feature Descriptor
2246 		 */
2247 		ret = ffs_do_single_os_desc(data, len, type,
2248 					    feature_count, entity, priv, desc);
2249 		if (unlikely(ret < 0)) {
2250 			pr_debug("%s returns %d\n", __func__, ret);
2251 			return ret;
2252 		}
2253 
2254 		len -= ret;
2255 		data += ret;
2256 	}
2257 	return _len - len;
2258 }
2259 
2260 /**
2261  * Validate contents of the buffer from userspace related to OS descriptors.
2262  */
2263 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2264 				 struct usb_os_desc_header *h, void *data,
2265 				 unsigned len, void *priv)
2266 {
2267 	struct ffs_data *ffs = priv;
2268 	u8 length;
2269 
2270 	ENTER();
2271 
2272 	switch (type) {
2273 	case FFS_OS_DESC_EXT_COMPAT: {
2274 		struct usb_ext_compat_desc *d = data;
2275 		int i;
2276 
2277 		if (len < sizeof(*d) ||
2278 		    d->bFirstInterfaceNumber >= ffs->interfaces_count)
2279 			return -EINVAL;
2280 		if (d->Reserved1 != 1) {
2281 			/*
2282 			 * According to the spec, Reserved1 must be set to 1
2283 			 * but older kernels incorrectly rejected non-zero
2284 			 * values.  We fix it here to avoid returning EINVAL
2285 			 * in response to values we used to accept.
2286 			 */
2287 			pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2288 			d->Reserved1 = 1;
2289 		}
2290 		for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2291 			if (d->Reserved2[i])
2292 				return -EINVAL;
2293 
2294 		length = sizeof(struct usb_ext_compat_desc);
2295 	}
2296 		break;
2297 	case FFS_OS_DESC_EXT_PROP: {
2298 		struct usb_ext_prop_desc *d = data;
2299 		u32 type, pdl;
2300 		u16 pnl;
2301 
2302 		if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2303 			return -EINVAL;
2304 		length = le32_to_cpu(d->dwSize);
2305 		if (len < length)
2306 			return -EINVAL;
2307 		type = le32_to_cpu(d->dwPropertyDataType);
2308 		if (type < USB_EXT_PROP_UNICODE ||
2309 		    type > USB_EXT_PROP_UNICODE_MULTI) {
2310 			pr_vdebug("unsupported os descriptor property type: %d",
2311 				  type);
2312 			return -EINVAL;
2313 		}
2314 		pnl = le16_to_cpu(d->wPropertyNameLength);
2315 		if (length < 14 + pnl) {
2316 			pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2317 				  length, pnl, type);
2318 			return -EINVAL;
2319 		}
2320 		pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2321 		if (length != 14 + pnl + pdl) {
2322 			pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2323 				  length, pnl, pdl, type);
2324 			return -EINVAL;
2325 		}
2326 		++ffs->ms_os_descs_ext_prop_count;
2327 		/* property name reported to the host as "WCHAR"s */
2328 		ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2329 		ffs->ms_os_descs_ext_prop_data_len += pdl;
2330 	}
2331 		break;
2332 	default:
2333 		pr_vdebug("unknown descriptor: %d\n", type);
2334 		return -EINVAL;
2335 	}
2336 	return length;
2337 }
2338 
2339 static int __ffs_data_got_descs(struct ffs_data *ffs,
2340 				char *const _data, size_t len)
2341 {
2342 	char *data = _data, *raw_descs;
2343 	unsigned os_descs_count = 0, counts[3], flags;
2344 	int ret = -EINVAL, i;
2345 	struct ffs_desc_helper helper;
2346 
2347 	ENTER();
2348 
2349 	if (get_unaligned_le32(data + 4) != len)
2350 		goto error;
2351 
2352 	switch (get_unaligned_le32(data)) {
2353 	case FUNCTIONFS_DESCRIPTORS_MAGIC:
2354 		flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2355 		data += 8;
2356 		len  -= 8;
2357 		break;
2358 	case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2359 		flags = get_unaligned_le32(data + 8);
2360 		ffs->user_flags = flags;
2361 		if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2362 			      FUNCTIONFS_HAS_HS_DESC |
2363 			      FUNCTIONFS_HAS_SS_DESC |
2364 			      FUNCTIONFS_HAS_MS_OS_DESC |
2365 			      FUNCTIONFS_VIRTUAL_ADDR |
2366 			      FUNCTIONFS_EVENTFD |
2367 			      FUNCTIONFS_ALL_CTRL_RECIP |
2368 			      FUNCTIONFS_CONFIG0_SETUP)) {
2369 			ret = -ENOSYS;
2370 			goto error;
2371 		}
2372 		data += 12;
2373 		len  -= 12;
2374 		break;
2375 	default:
2376 		goto error;
2377 	}
2378 
2379 	if (flags & FUNCTIONFS_EVENTFD) {
2380 		if (len < 4)
2381 			goto error;
2382 		ffs->ffs_eventfd =
2383 			eventfd_ctx_fdget((int)get_unaligned_le32(data));
2384 		if (IS_ERR(ffs->ffs_eventfd)) {
2385 			ret = PTR_ERR(ffs->ffs_eventfd);
2386 			ffs->ffs_eventfd = NULL;
2387 			goto error;
2388 		}
2389 		data += 4;
2390 		len  -= 4;
2391 	}
2392 
2393 	/* Read fs_count, hs_count and ss_count (if present) */
2394 	for (i = 0; i < 3; ++i) {
2395 		if (!(flags & (1 << i))) {
2396 			counts[i] = 0;
2397 		} else if (len < 4) {
2398 			goto error;
2399 		} else {
2400 			counts[i] = get_unaligned_le32(data);
2401 			data += 4;
2402 			len  -= 4;
2403 		}
2404 	}
2405 	if (flags & (1 << i)) {
2406 		if (len < 4) {
2407 			goto error;
2408 		}
2409 		os_descs_count = get_unaligned_le32(data);
2410 		data += 4;
2411 		len -= 4;
2412 	};
2413 
2414 	/* Read descriptors */
2415 	raw_descs = data;
2416 	helper.ffs = ffs;
2417 	for (i = 0; i < 3; ++i) {
2418 		if (!counts[i])
2419 			continue;
2420 		helper.interfaces_count = 0;
2421 		helper.eps_count = 0;
2422 		ret = ffs_do_descs(counts[i], data, len,
2423 				   __ffs_data_do_entity, &helper);
2424 		if (ret < 0)
2425 			goto error;
2426 		if (!ffs->eps_count && !ffs->interfaces_count) {
2427 			ffs->eps_count = helper.eps_count;
2428 			ffs->interfaces_count = helper.interfaces_count;
2429 		} else {
2430 			if (ffs->eps_count != helper.eps_count) {
2431 				ret = -EINVAL;
2432 				goto error;
2433 			}
2434 			if (ffs->interfaces_count != helper.interfaces_count) {
2435 				ret = -EINVAL;
2436 				goto error;
2437 			}
2438 		}
2439 		data += ret;
2440 		len  -= ret;
2441 	}
2442 	if (os_descs_count) {
2443 		ret = ffs_do_os_descs(os_descs_count, data, len,
2444 				      __ffs_data_do_os_desc, ffs);
2445 		if (ret < 0)
2446 			goto error;
2447 		data += ret;
2448 		len -= ret;
2449 	}
2450 
2451 	if (raw_descs == data || len) {
2452 		ret = -EINVAL;
2453 		goto error;
2454 	}
2455 
2456 	ffs->raw_descs_data	= _data;
2457 	ffs->raw_descs		= raw_descs;
2458 	ffs->raw_descs_length	= data - raw_descs;
2459 	ffs->fs_descs_count	= counts[0];
2460 	ffs->hs_descs_count	= counts[1];
2461 	ffs->ss_descs_count	= counts[2];
2462 	ffs->ms_os_descs_count	= os_descs_count;
2463 
2464 	return 0;
2465 
2466 error:
2467 	kfree(_data);
2468 	return ret;
2469 }
2470 
2471 static int __ffs_data_got_strings(struct ffs_data *ffs,
2472 				  char *const _data, size_t len)
2473 {
2474 	u32 str_count, needed_count, lang_count;
2475 	struct usb_gadget_strings **stringtabs, *t;
2476 	const char *data = _data;
2477 	struct usb_string *s;
2478 
2479 	ENTER();
2480 
2481 	if (unlikely(len < 16 ||
2482 		     get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2483 		     get_unaligned_le32(data + 4) != len))
2484 		goto error;
2485 	str_count  = get_unaligned_le32(data + 8);
2486 	lang_count = get_unaligned_le32(data + 12);
2487 
2488 	/* if one is zero the other must be zero */
2489 	if (unlikely(!str_count != !lang_count))
2490 		goto error;
2491 
2492 	/* Do we have at least as many strings as descriptors need? */
2493 	needed_count = ffs->strings_count;
2494 	if (unlikely(str_count < needed_count))
2495 		goto error;
2496 
2497 	/*
2498 	 * If we don't need any strings just return and free all
2499 	 * memory.
2500 	 */
2501 	if (!needed_count) {
2502 		kfree(_data);
2503 		return 0;
2504 	}
2505 
2506 	/* Allocate everything in one chunk so there's less maintenance. */
2507 	{
2508 		unsigned i = 0;
2509 		vla_group(d);
2510 		vla_item(d, struct usb_gadget_strings *, stringtabs,
2511 			lang_count + 1);
2512 		vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2513 		vla_item(d, struct usb_string, strings,
2514 			lang_count*(needed_count+1));
2515 
2516 		char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2517 
2518 		if (unlikely(!vlabuf)) {
2519 			kfree(_data);
2520 			return -ENOMEM;
2521 		}
2522 
2523 		/* Initialize the VLA pointers */
2524 		stringtabs = vla_ptr(vlabuf, d, stringtabs);
2525 		t = vla_ptr(vlabuf, d, stringtab);
2526 		i = lang_count;
2527 		do {
2528 			*stringtabs++ = t++;
2529 		} while (--i);
2530 		*stringtabs = NULL;
2531 
2532 		/* stringtabs = vlabuf = d_stringtabs for later kfree */
2533 		stringtabs = vla_ptr(vlabuf, d, stringtabs);
2534 		t = vla_ptr(vlabuf, d, stringtab);
2535 		s = vla_ptr(vlabuf, d, strings);
2536 	}
2537 
2538 	/* For each language */
2539 	data += 16;
2540 	len -= 16;
2541 
2542 	do { /* lang_count > 0 so we can use do-while */
2543 		unsigned needed = needed_count;
2544 
2545 		if (unlikely(len < 3))
2546 			goto error_free;
2547 		t->language = get_unaligned_le16(data);
2548 		t->strings  = s;
2549 		++t;
2550 
2551 		data += 2;
2552 		len -= 2;
2553 
2554 		/* For each string */
2555 		do { /* str_count > 0 so we can use do-while */
2556 			size_t length = strnlen(data, len);
2557 
2558 			if (unlikely(length == len))
2559 				goto error_free;
2560 
2561 			/*
2562 			 * User may provide more strings then we need,
2563 			 * if that's the case we simply ignore the
2564 			 * rest
2565 			 */
2566 			if (likely(needed)) {
2567 				/*
2568 				 * s->id will be set while adding
2569 				 * function to configuration so for
2570 				 * now just leave garbage here.
2571 				 */
2572 				s->s = data;
2573 				--needed;
2574 				++s;
2575 			}
2576 
2577 			data += length + 1;
2578 			len -= length + 1;
2579 		} while (--str_count);
2580 
2581 		s->id = 0;   /* terminator */
2582 		s->s = NULL;
2583 		++s;
2584 
2585 	} while (--lang_count);
2586 
2587 	/* Some garbage left? */
2588 	if (unlikely(len))
2589 		goto error_free;
2590 
2591 	/* Done! */
2592 	ffs->stringtabs = stringtabs;
2593 	ffs->raw_strings = _data;
2594 
2595 	return 0;
2596 
2597 error_free:
2598 	kfree(stringtabs);
2599 error:
2600 	kfree(_data);
2601 	return -EINVAL;
2602 }
2603 
2604 
2605 /* Events handling and management *******************************************/
2606 
2607 static void __ffs_event_add(struct ffs_data *ffs,
2608 			    enum usb_functionfs_event_type type)
2609 {
2610 	enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2611 	int neg = 0;
2612 
2613 	/*
2614 	 * Abort any unhandled setup
2615 	 *
2616 	 * We do not need to worry about some cmpxchg() changing value
2617 	 * of ffs->setup_state without holding the lock because when
2618 	 * state is FFS_SETUP_PENDING cmpxchg() in several places in
2619 	 * the source does nothing.
2620 	 */
2621 	if (ffs->setup_state == FFS_SETUP_PENDING)
2622 		ffs->setup_state = FFS_SETUP_CANCELLED;
2623 
2624 	/*
2625 	 * Logic of this function guarantees that there are at most four pending
2626 	 * evens on ffs->ev.types queue.  This is important because the queue
2627 	 * has space for four elements only and __ffs_ep0_read_events function
2628 	 * depends on that limit as well.  If more event types are added, those
2629 	 * limits have to be revisited or guaranteed to still hold.
2630 	 */
2631 	switch (type) {
2632 	case FUNCTIONFS_RESUME:
2633 		rem_type2 = FUNCTIONFS_SUSPEND;
2634 		/* FALL THROUGH */
2635 	case FUNCTIONFS_SUSPEND:
2636 	case FUNCTIONFS_SETUP:
2637 		rem_type1 = type;
2638 		/* Discard all similar events */
2639 		break;
2640 
2641 	case FUNCTIONFS_BIND:
2642 	case FUNCTIONFS_UNBIND:
2643 	case FUNCTIONFS_DISABLE:
2644 	case FUNCTIONFS_ENABLE:
2645 		/* Discard everything other then power management. */
2646 		rem_type1 = FUNCTIONFS_SUSPEND;
2647 		rem_type2 = FUNCTIONFS_RESUME;
2648 		neg = 1;
2649 		break;
2650 
2651 	default:
2652 		WARN(1, "%d: unknown event, this should not happen\n", type);
2653 		return;
2654 	}
2655 
2656 	{
2657 		u8 *ev  = ffs->ev.types, *out = ev;
2658 		unsigned n = ffs->ev.count;
2659 		for (; n; --n, ++ev)
2660 			if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2661 				*out++ = *ev;
2662 			else
2663 				pr_vdebug("purging event %d\n", *ev);
2664 		ffs->ev.count = out - ffs->ev.types;
2665 	}
2666 
2667 	pr_vdebug("adding event %d\n", type);
2668 	ffs->ev.types[ffs->ev.count++] = type;
2669 	wake_up_locked(&ffs->ev.waitq);
2670 	if (ffs->ffs_eventfd)
2671 		eventfd_signal(ffs->ffs_eventfd, 1);
2672 }
2673 
2674 static void ffs_event_add(struct ffs_data *ffs,
2675 			  enum usb_functionfs_event_type type)
2676 {
2677 	unsigned long flags;
2678 	spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2679 	__ffs_event_add(ffs, type);
2680 	spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2681 }
2682 
2683 /* Bind/unbind USB function hooks *******************************************/
2684 
2685 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2686 {
2687 	int i;
2688 
2689 	for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2690 		if (ffs->eps_addrmap[i] == endpoint_address)
2691 			return i;
2692 	return -ENOENT;
2693 }
2694 
2695 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2696 				    struct usb_descriptor_header *desc,
2697 				    void *priv)
2698 {
2699 	struct usb_endpoint_descriptor *ds = (void *)desc;
2700 	struct ffs_function *func = priv;
2701 	struct ffs_ep *ffs_ep;
2702 	unsigned ep_desc_id;
2703 	int idx;
2704 	static const char *speed_names[] = { "full", "high", "super" };
2705 
2706 	if (type != FFS_DESCRIPTOR)
2707 		return 0;
2708 
2709 	/*
2710 	 * If ss_descriptors is not NULL, we are reading super speed
2711 	 * descriptors; if hs_descriptors is not NULL, we are reading high
2712 	 * speed descriptors; otherwise, we are reading full speed
2713 	 * descriptors.
2714 	 */
2715 	if (func->function.ss_descriptors) {
2716 		ep_desc_id = 2;
2717 		func->function.ss_descriptors[(long)valuep] = desc;
2718 	} else if (func->function.hs_descriptors) {
2719 		ep_desc_id = 1;
2720 		func->function.hs_descriptors[(long)valuep] = desc;
2721 	} else {
2722 		ep_desc_id = 0;
2723 		func->function.fs_descriptors[(long)valuep]    = desc;
2724 	}
2725 
2726 	if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2727 		return 0;
2728 
2729 	idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2730 	if (idx < 0)
2731 		return idx;
2732 
2733 	ffs_ep = func->eps + idx;
2734 
2735 	if (unlikely(ffs_ep->descs[ep_desc_id])) {
2736 		pr_err("two %sspeed descriptors for EP %d\n",
2737 			  speed_names[ep_desc_id],
2738 			  ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2739 		return -EINVAL;
2740 	}
2741 	ffs_ep->descs[ep_desc_id] = ds;
2742 
2743 	ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2744 	if (ffs_ep->ep) {
2745 		ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2746 		if (!ds->wMaxPacketSize)
2747 			ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2748 	} else {
2749 		struct usb_request *req;
2750 		struct usb_ep *ep;
2751 		u8 bEndpointAddress;
2752 
2753 		/*
2754 		 * We back up bEndpointAddress because autoconfig overwrites
2755 		 * it with physical endpoint address.
2756 		 */
2757 		bEndpointAddress = ds->bEndpointAddress;
2758 		pr_vdebug("autoconfig\n");
2759 		ep = usb_ep_autoconfig(func->gadget, ds);
2760 		if (unlikely(!ep))
2761 			return -ENOTSUPP;
2762 		ep->driver_data = func->eps + idx;
2763 
2764 		req = usb_ep_alloc_request(ep, GFP_KERNEL);
2765 		if (unlikely(!req))
2766 			return -ENOMEM;
2767 
2768 		ffs_ep->ep  = ep;
2769 		ffs_ep->req = req;
2770 		func->eps_revmap[ds->bEndpointAddress &
2771 				 USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2772 		/*
2773 		 * If we use virtual address mapping, we restore
2774 		 * original bEndpointAddress value.
2775 		 */
2776 		if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2777 			ds->bEndpointAddress = bEndpointAddress;
2778 	}
2779 	ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2780 
2781 	return 0;
2782 }
2783 
2784 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2785 				   struct usb_descriptor_header *desc,
2786 				   void *priv)
2787 {
2788 	struct ffs_function *func = priv;
2789 	unsigned idx;
2790 	u8 newValue;
2791 
2792 	switch (type) {
2793 	default:
2794 	case FFS_DESCRIPTOR:
2795 		/* Handled in previous pass by __ffs_func_bind_do_descs() */
2796 		return 0;
2797 
2798 	case FFS_INTERFACE:
2799 		idx = *valuep;
2800 		if (func->interfaces_nums[idx] < 0) {
2801 			int id = usb_interface_id(func->conf, &func->function);
2802 			if (unlikely(id < 0))
2803 				return id;
2804 			func->interfaces_nums[idx] = id;
2805 		}
2806 		newValue = func->interfaces_nums[idx];
2807 		break;
2808 
2809 	case FFS_STRING:
2810 		/* String' IDs are allocated when fsf_data is bound to cdev */
2811 		newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2812 		break;
2813 
2814 	case FFS_ENDPOINT:
2815 		/*
2816 		 * USB_DT_ENDPOINT are handled in
2817 		 * __ffs_func_bind_do_descs().
2818 		 */
2819 		if (desc->bDescriptorType == USB_DT_ENDPOINT)
2820 			return 0;
2821 
2822 		idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2823 		if (unlikely(!func->eps[idx].ep))
2824 			return -EINVAL;
2825 
2826 		{
2827 			struct usb_endpoint_descriptor **descs;
2828 			descs = func->eps[idx].descs;
2829 			newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2830 		}
2831 		break;
2832 	}
2833 
2834 	pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2835 	*valuep = newValue;
2836 	return 0;
2837 }
2838 
2839 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2840 				      struct usb_os_desc_header *h, void *data,
2841 				      unsigned len, void *priv)
2842 {
2843 	struct ffs_function *func = priv;
2844 	u8 length = 0;
2845 
2846 	switch (type) {
2847 	case FFS_OS_DESC_EXT_COMPAT: {
2848 		struct usb_ext_compat_desc *desc = data;
2849 		struct usb_os_desc_table *t;
2850 
2851 		t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2852 		t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2853 		memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2854 		       ARRAY_SIZE(desc->CompatibleID) +
2855 		       ARRAY_SIZE(desc->SubCompatibleID));
2856 		length = sizeof(*desc);
2857 	}
2858 		break;
2859 	case FFS_OS_DESC_EXT_PROP: {
2860 		struct usb_ext_prop_desc *desc = data;
2861 		struct usb_os_desc_table *t;
2862 		struct usb_os_desc_ext_prop *ext_prop;
2863 		char *ext_prop_name;
2864 		char *ext_prop_data;
2865 
2866 		t = &func->function.os_desc_table[h->interface];
2867 		t->if_id = func->interfaces_nums[h->interface];
2868 
2869 		ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2870 		func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2871 
2872 		ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2873 		ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2874 		ext_prop->data_len = le32_to_cpu(*(__le32 *)
2875 			usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2876 		length = ext_prop->name_len + ext_prop->data_len + 14;
2877 
2878 		ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2879 		func->ffs->ms_os_descs_ext_prop_name_avail +=
2880 			ext_prop->name_len;
2881 
2882 		ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2883 		func->ffs->ms_os_descs_ext_prop_data_avail +=
2884 			ext_prop->data_len;
2885 		memcpy(ext_prop_data,
2886 		       usb_ext_prop_data_ptr(data, ext_prop->name_len),
2887 		       ext_prop->data_len);
2888 		/* unicode data reported to the host as "WCHAR"s */
2889 		switch (ext_prop->type) {
2890 		case USB_EXT_PROP_UNICODE:
2891 		case USB_EXT_PROP_UNICODE_ENV:
2892 		case USB_EXT_PROP_UNICODE_LINK:
2893 		case USB_EXT_PROP_UNICODE_MULTI:
2894 			ext_prop->data_len *= 2;
2895 			break;
2896 		}
2897 		ext_prop->data = ext_prop_data;
2898 
2899 		memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2900 		       ext_prop->name_len);
2901 		/* property name reported to the host as "WCHAR"s */
2902 		ext_prop->name_len *= 2;
2903 		ext_prop->name = ext_prop_name;
2904 
2905 		t->os_desc->ext_prop_len +=
2906 			ext_prop->name_len + ext_prop->data_len + 14;
2907 		++t->os_desc->ext_prop_count;
2908 		list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2909 	}
2910 		break;
2911 	default:
2912 		pr_vdebug("unknown descriptor: %d\n", type);
2913 	}
2914 
2915 	return length;
2916 }
2917 
2918 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2919 						struct usb_configuration *c)
2920 {
2921 	struct ffs_function *func = ffs_func_from_usb(f);
2922 	struct f_fs_opts *ffs_opts =
2923 		container_of(f->fi, struct f_fs_opts, func_inst);
2924 	int ret;
2925 
2926 	ENTER();
2927 
2928 	/*
2929 	 * Legacy gadget triggers binding in functionfs_ready_callback,
2930 	 * which already uses locking; taking the same lock here would
2931 	 * cause a deadlock.
2932 	 *
2933 	 * Configfs-enabled gadgets however do need ffs_dev_lock.
2934 	 */
2935 	if (!ffs_opts->no_configfs)
2936 		ffs_dev_lock();
2937 	ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2938 	func->ffs = ffs_opts->dev->ffs_data;
2939 	if (!ffs_opts->no_configfs)
2940 		ffs_dev_unlock();
2941 	if (ret)
2942 		return ERR_PTR(ret);
2943 
2944 	func->conf = c;
2945 	func->gadget = c->cdev->gadget;
2946 
2947 	/*
2948 	 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2949 	 * configurations are bound in sequence with list_for_each_entry,
2950 	 * in each configuration its functions are bound in sequence
2951 	 * with list_for_each_entry, so we assume no race condition
2952 	 * with regard to ffs_opts->bound access
2953 	 */
2954 	if (!ffs_opts->refcnt) {
2955 		ret = functionfs_bind(func->ffs, c->cdev);
2956 		if (ret)
2957 			return ERR_PTR(ret);
2958 	}
2959 	ffs_opts->refcnt++;
2960 	func->function.strings = func->ffs->stringtabs;
2961 
2962 	return ffs_opts;
2963 }
2964 
2965 static int _ffs_func_bind(struct usb_configuration *c,
2966 			  struct usb_function *f)
2967 {
2968 	struct ffs_function *func = ffs_func_from_usb(f);
2969 	struct ffs_data *ffs = func->ffs;
2970 
2971 	const int full = !!func->ffs->fs_descs_count;
2972 	const int high = !!func->ffs->hs_descs_count;
2973 	const int super = !!func->ffs->ss_descs_count;
2974 
2975 	int fs_len, hs_len, ss_len, ret, i;
2976 	struct ffs_ep *eps_ptr;
2977 
2978 	/* Make it a single chunk, less management later on */
2979 	vla_group(d);
2980 	vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2981 	vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2982 		full ? ffs->fs_descs_count + 1 : 0);
2983 	vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2984 		high ? ffs->hs_descs_count + 1 : 0);
2985 	vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2986 		super ? ffs->ss_descs_count + 1 : 0);
2987 	vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2988 	vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2989 			 c->cdev->use_os_string ? ffs->interfaces_count : 0);
2990 	vla_item_with_sz(d, char[16], ext_compat,
2991 			 c->cdev->use_os_string ? ffs->interfaces_count : 0);
2992 	vla_item_with_sz(d, struct usb_os_desc, os_desc,
2993 			 c->cdev->use_os_string ? ffs->interfaces_count : 0);
2994 	vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
2995 			 ffs->ms_os_descs_ext_prop_count);
2996 	vla_item_with_sz(d, char, ext_prop_name,
2997 			 ffs->ms_os_descs_ext_prop_name_len);
2998 	vla_item_with_sz(d, char, ext_prop_data,
2999 			 ffs->ms_os_descs_ext_prop_data_len);
3000 	vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3001 	char *vlabuf;
3002 
3003 	ENTER();
3004 
3005 	/* Has descriptors only for speeds gadget does not support */
3006 	if (unlikely(!(full | high | super)))
3007 		return -ENOTSUPP;
3008 
3009 	/* Allocate a single chunk, less management later on */
3010 	vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3011 	if (unlikely(!vlabuf))
3012 		return -ENOMEM;
3013 
3014 	ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3015 	ffs->ms_os_descs_ext_prop_name_avail =
3016 		vla_ptr(vlabuf, d, ext_prop_name);
3017 	ffs->ms_os_descs_ext_prop_data_avail =
3018 		vla_ptr(vlabuf, d, ext_prop_data);
3019 
3020 	/* Copy descriptors  */
3021 	memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3022 	       ffs->raw_descs_length);
3023 
3024 	memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3025 	eps_ptr = vla_ptr(vlabuf, d, eps);
3026 	for (i = 0; i < ffs->eps_count; i++)
3027 		eps_ptr[i].num = -1;
3028 
3029 	/* Save pointers
3030 	 * d_eps == vlabuf, func->eps used to kfree vlabuf later
3031 	*/
3032 	func->eps             = vla_ptr(vlabuf, d, eps);
3033 	func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3034 
3035 	/*
3036 	 * Go through all the endpoint descriptors and allocate
3037 	 * endpoints first, so that later we can rewrite the endpoint
3038 	 * numbers without worrying that it may be described later on.
3039 	 */
3040 	if (likely(full)) {
3041 		func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3042 		fs_len = ffs_do_descs(ffs->fs_descs_count,
3043 				      vla_ptr(vlabuf, d, raw_descs),
3044 				      d_raw_descs__sz,
3045 				      __ffs_func_bind_do_descs, func);
3046 		if (unlikely(fs_len < 0)) {
3047 			ret = fs_len;
3048 			goto error;
3049 		}
3050 	} else {
3051 		fs_len = 0;
3052 	}
3053 
3054 	if (likely(high)) {
3055 		func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3056 		hs_len = ffs_do_descs(ffs->hs_descs_count,
3057 				      vla_ptr(vlabuf, d, raw_descs) + fs_len,
3058 				      d_raw_descs__sz - fs_len,
3059 				      __ffs_func_bind_do_descs, func);
3060 		if (unlikely(hs_len < 0)) {
3061 			ret = hs_len;
3062 			goto error;
3063 		}
3064 	} else {
3065 		hs_len = 0;
3066 	}
3067 
3068 	if (likely(super)) {
3069 		func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3070 		ss_len = ffs_do_descs(ffs->ss_descs_count,
3071 				vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3072 				d_raw_descs__sz - fs_len - hs_len,
3073 				__ffs_func_bind_do_descs, func);
3074 		if (unlikely(ss_len < 0)) {
3075 			ret = ss_len;
3076 			goto error;
3077 		}
3078 	} else {
3079 		ss_len = 0;
3080 	}
3081 
3082 	/*
3083 	 * Now handle interface numbers allocation and interface and
3084 	 * endpoint numbers rewriting.  We can do that in one go
3085 	 * now.
3086 	 */
3087 	ret = ffs_do_descs(ffs->fs_descs_count +
3088 			   (high ? ffs->hs_descs_count : 0) +
3089 			   (super ? ffs->ss_descs_count : 0),
3090 			   vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3091 			   __ffs_func_bind_do_nums, func);
3092 	if (unlikely(ret < 0))
3093 		goto error;
3094 
3095 	func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3096 	if (c->cdev->use_os_string) {
3097 		for (i = 0; i < ffs->interfaces_count; ++i) {
3098 			struct usb_os_desc *desc;
3099 
3100 			desc = func->function.os_desc_table[i].os_desc =
3101 				vla_ptr(vlabuf, d, os_desc) +
3102 				i * sizeof(struct usb_os_desc);
3103 			desc->ext_compat_id =
3104 				vla_ptr(vlabuf, d, ext_compat) + i * 16;
3105 			INIT_LIST_HEAD(&desc->ext_prop);
3106 		}
3107 		ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3108 				      vla_ptr(vlabuf, d, raw_descs) +
3109 				      fs_len + hs_len + ss_len,
3110 				      d_raw_descs__sz - fs_len - hs_len -
3111 				      ss_len,
3112 				      __ffs_func_bind_do_os_desc, func);
3113 		if (unlikely(ret < 0))
3114 			goto error;
3115 	}
3116 	func->function.os_desc_n =
3117 		c->cdev->use_os_string ? ffs->interfaces_count : 0;
3118 
3119 	/* And we're done */
3120 	ffs_event_add(ffs, FUNCTIONFS_BIND);
3121 	return 0;
3122 
3123 error:
3124 	/* XXX Do we need to release all claimed endpoints here? */
3125 	return ret;
3126 }
3127 
3128 static int ffs_func_bind(struct usb_configuration *c,
3129 			 struct usb_function *f)
3130 {
3131 	struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3132 	struct ffs_function *func = ffs_func_from_usb(f);
3133 	int ret;
3134 
3135 	if (IS_ERR(ffs_opts))
3136 		return PTR_ERR(ffs_opts);
3137 
3138 	ret = _ffs_func_bind(c, f);
3139 	if (ret && !--ffs_opts->refcnt)
3140 		functionfs_unbind(func->ffs);
3141 
3142 	return ret;
3143 }
3144 
3145 
3146 /* Other USB function hooks *************************************************/
3147 
3148 static void ffs_reset_work(struct work_struct *work)
3149 {
3150 	struct ffs_data *ffs = container_of(work,
3151 		struct ffs_data, reset_work);
3152 	ffs_data_reset(ffs);
3153 }
3154 
3155 static int ffs_func_set_alt(struct usb_function *f,
3156 			    unsigned interface, unsigned alt)
3157 {
3158 	struct ffs_function *func = ffs_func_from_usb(f);
3159 	struct ffs_data *ffs = func->ffs;
3160 	int ret = 0, intf;
3161 
3162 	if (alt != (unsigned)-1) {
3163 		intf = ffs_func_revmap_intf(func, interface);
3164 		if (unlikely(intf < 0))
3165 			return intf;
3166 	}
3167 
3168 	if (ffs->func)
3169 		ffs_func_eps_disable(ffs->func);
3170 
3171 	if (ffs->state == FFS_DEACTIVATED) {
3172 		ffs->state = FFS_CLOSING;
3173 		INIT_WORK(&ffs->reset_work, ffs_reset_work);
3174 		schedule_work(&ffs->reset_work);
3175 		return -ENODEV;
3176 	}
3177 
3178 	if (ffs->state != FFS_ACTIVE)
3179 		return -ENODEV;
3180 
3181 	if (alt == (unsigned)-1) {
3182 		ffs->func = NULL;
3183 		ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3184 		return 0;
3185 	}
3186 
3187 	ffs->func = func;
3188 	ret = ffs_func_eps_enable(func);
3189 	if (likely(ret >= 0))
3190 		ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3191 	return ret;
3192 }
3193 
3194 static void ffs_func_disable(struct usb_function *f)
3195 {
3196 	ffs_func_set_alt(f, 0, (unsigned)-1);
3197 }
3198 
3199 static int ffs_func_setup(struct usb_function *f,
3200 			  const struct usb_ctrlrequest *creq)
3201 {
3202 	struct ffs_function *func = ffs_func_from_usb(f);
3203 	struct ffs_data *ffs = func->ffs;
3204 	unsigned long flags;
3205 	int ret;
3206 
3207 	ENTER();
3208 
3209 	pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3210 	pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3211 	pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3212 	pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3213 	pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3214 
3215 	/*
3216 	 * Most requests directed to interface go through here
3217 	 * (notable exceptions are set/get interface) so we need to
3218 	 * handle them.  All other either handled by composite or
3219 	 * passed to usb_configuration->setup() (if one is set).  No
3220 	 * matter, we will handle requests directed to endpoint here
3221 	 * as well (as it's straightforward).  Other request recipient
3222 	 * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3223 	 * is being used.
3224 	 */
3225 	if (ffs->state != FFS_ACTIVE)
3226 		return -ENODEV;
3227 
3228 	switch (creq->bRequestType & USB_RECIP_MASK) {
3229 	case USB_RECIP_INTERFACE:
3230 		ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3231 		if (unlikely(ret < 0))
3232 			return ret;
3233 		break;
3234 
3235 	case USB_RECIP_ENDPOINT:
3236 		ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3237 		if (unlikely(ret < 0))
3238 			return ret;
3239 		if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3240 			ret = func->ffs->eps_addrmap[ret];
3241 		break;
3242 
3243 	default:
3244 		if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3245 			ret = le16_to_cpu(creq->wIndex);
3246 		else
3247 			return -EOPNOTSUPP;
3248 	}
3249 
3250 	spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3251 	ffs->ev.setup = *creq;
3252 	ffs->ev.setup.wIndex = cpu_to_le16(ret);
3253 	__ffs_event_add(ffs, FUNCTIONFS_SETUP);
3254 	spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3255 
3256 	return USB_GADGET_DELAYED_STATUS;
3257 }
3258 
3259 static bool ffs_func_req_match(struct usb_function *f,
3260 			       const struct usb_ctrlrequest *creq,
3261 			       bool config0)
3262 {
3263 	struct ffs_function *func = ffs_func_from_usb(f);
3264 
3265 	if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3266 		return false;
3267 
3268 	switch (creq->bRequestType & USB_RECIP_MASK) {
3269 	case USB_RECIP_INTERFACE:
3270 		return (ffs_func_revmap_intf(func,
3271 					     le16_to_cpu(creq->wIndex)) >= 0);
3272 	case USB_RECIP_ENDPOINT:
3273 		return (ffs_func_revmap_ep(func,
3274 					   le16_to_cpu(creq->wIndex)) >= 0);
3275 	default:
3276 		return (bool) (func->ffs->user_flags &
3277 			       FUNCTIONFS_ALL_CTRL_RECIP);
3278 	}
3279 }
3280 
3281 static void ffs_func_suspend(struct usb_function *f)
3282 {
3283 	ENTER();
3284 	ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3285 }
3286 
3287 static void ffs_func_resume(struct usb_function *f)
3288 {
3289 	ENTER();
3290 	ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3291 }
3292 
3293 
3294 /* Endpoint and interface numbers reverse mapping ***************************/
3295 
3296 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3297 {
3298 	num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3299 	return num ? num : -EDOM;
3300 }
3301 
3302 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3303 {
3304 	short *nums = func->interfaces_nums;
3305 	unsigned count = func->ffs->interfaces_count;
3306 
3307 	for (; count; --count, ++nums) {
3308 		if (*nums >= 0 && *nums == intf)
3309 			return nums - func->interfaces_nums;
3310 	}
3311 
3312 	return -EDOM;
3313 }
3314 
3315 
3316 /* Devices management *******************************************************/
3317 
3318 static LIST_HEAD(ffs_devices);
3319 
3320 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3321 {
3322 	struct ffs_dev *dev;
3323 
3324 	if (!name)
3325 		return NULL;
3326 
3327 	list_for_each_entry(dev, &ffs_devices, entry) {
3328 		if (strcmp(dev->name, name) == 0)
3329 			return dev;
3330 	}
3331 
3332 	return NULL;
3333 }
3334 
3335 /*
3336  * ffs_lock must be taken by the caller of this function
3337  */
3338 static struct ffs_dev *_ffs_get_single_dev(void)
3339 {
3340 	struct ffs_dev *dev;
3341 
3342 	if (list_is_singular(&ffs_devices)) {
3343 		dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3344 		if (dev->single)
3345 			return dev;
3346 	}
3347 
3348 	return NULL;
3349 }
3350 
3351 /*
3352  * ffs_lock must be taken by the caller of this function
3353  */
3354 static struct ffs_dev *_ffs_find_dev(const char *name)
3355 {
3356 	struct ffs_dev *dev;
3357 
3358 	dev = _ffs_get_single_dev();
3359 	if (dev)
3360 		return dev;
3361 
3362 	return _ffs_do_find_dev(name);
3363 }
3364 
3365 /* Configfs support *********************************************************/
3366 
3367 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3368 {
3369 	return container_of(to_config_group(item), struct f_fs_opts,
3370 			    func_inst.group);
3371 }
3372 
3373 static void ffs_attr_release(struct config_item *item)
3374 {
3375 	struct f_fs_opts *opts = to_ffs_opts(item);
3376 
3377 	usb_put_function_instance(&opts->func_inst);
3378 }
3379 
3380 static struct configfs_item_operations ffs_item_ops = {
3381 	.release	= ffs_attr_release,
3382 };
3383 
3384 static const struct config_item_type ffs_func_type = {
3385 	.ct_item_ops	= &ffs_item_ops,
3386 	.ct_owner	= THIS_MODULE,
3387 };
3388 
3389 
3390 /* Function registration interface ******************************************/
3391 
3392 static void ffs_free_inst(struct usb_function_instance *f)
3393 {
3394 	struct f_fs_opts *opts;
3395 
3396 	opts = to_f_fs_opts(f);
3397 	ffs_dev_lock();
3398 	_ffs_free_dev(opts->dev);
3399 	ffs_dev_unlock();
3400 	kfree(opts);
3401 }
3402 
3403 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3404 {
3405 	if (strlen(name) >= FIELD_SIZEOF(struct ffs_dev, name))
3406 		return -ENAMETOOLONG;
3407 	return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3408 }
3409 
3410 static struct usb_function_instance *ffs_alloc_inst(void)
3411 {
3412 	struct f_fs_opts *opts;
3413 	struct ffs_dev *dev;
3414 
3415 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3416 	if (!opts)
3417 		return ERR_PTR(-ENOMEM);
3418 
3419 	opts->func_inst.set_inst_name = ffs_set_inst_name;
3420 	opts->func_inst.free_func_inst = ffs_free_inst;
3421 	ffs_dev_lock();
3422 	dev = _ffs_alloc_dev();
3423 	ffs_dev_unlock();
3424 	if (IS_ERR(dev)) {
3425 		kfree(opts);
3426 		return ERR_CAST(dev);
3427 	}
3428 	opts->dev = dev;
3429 	dev->opts = opts;
3430 
3431 	config_group_init_type_name(&opts->func_inst.group, "",
3432 				    &ffs_func_type);
3433 	return &opts->func_inst;
3434 }
3435 
3436 static void ffs_free(struct usb_function *f)
3437 {
3438 	kfree(ffs_func_from_usb(f));
3439 }
3440 
3441 static void ffs_func_unbind(struct usb_configuration *c,
3442 			    struct usb_function *f)
3443 {
3444 	struct ffs_function *func = ffs_func_from_usb(f);
3445 	struct ffs_data *ffs = func->ffs;
3446 	struct f_fs_opts *opts =
3447 		container_of(f->fi, struct f_fs_opts, func_inst);
3448 	struct ffs_ep *ep = func->eps;
3449 	unsigned count = ffs->eps_count;
3450 	unsigned long flags;
3451 
3452 	ENTER();
3453 	if (ffs->func == func) {
3454 		ffs_func_eps_disable(func);
3455 		ffs->func = NULL;
3456 	}
3457 
3458 	if (!--opts->refcnt)
3459 		functionfs_unbind(ffs);
3460 
3461 	/* cleanup after autoconfig */
3462 	spin_lock_irqsave(&func->ffs->eps_lock, flags);
3463 	while (count--) {
3464 		if (ep->ep && ep->req)
3465 			usb_ep_free_request(ep->ep, ep->req);
3466 		ep->req = NULL;
3467 		++ep;
3468 	}
3469 	spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3470 	kfree(func->eps);
3471 	func->eps = NULL;
3472 	/*
3473 	 * eps, descriptors and interfaces_nums are allocated in the
3474 	 * same chunk so only one free is required.
3475 	 */
3476 	func->function.fs_descriptors = NULL;
3477 	func->function.hs_descriptors = NULL;
3478 	func->function.ss_descriptors = NULL;
3479 	func->interfaces_nums = NULL;
3480 
3481 	ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3482 }
3483 
3484 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3485 {
3486 	struct ffs_function *func;
3487 
3488 	ENTER();
3489 
3490 	func = kzalloc(sizeof(*func), GFP_KERNEL);
3491 	if (unlikely(!func))
3492 		return ERR_PTR(-ENOMEM);
3493 
3494 	func->function.name    = "Function FS Gadget";
3495 
3496 	func->function.bind    = ffs_func_bind;
3497 	func->function.unbind  = ffs_func_unbind;
3498 	func->function.set_alt = ffs_func_set_alt;
3499 	func->function.disable = ffs_func_disable;
3500 	func->function.setup   = ffs_func_setup;
3501 	func->function.req_match = ffs_func_req_match;
3502 	func->function.suspend = ffs_func_suspend;
3503 	func->function.resume  = ffs_func_resume;
3504 	func->function.free_func = ffs_free;
3505 
3506 	return &func->function;
3507 }
3508 
3509 /*
3510  * ffs_lock must be taken by the caller of this function
3511  */
3512 static struct ffs_dev *_ffs_alloc_dev(void)
3513 {
3514 	struct ffs_dev *dev;
3515 	int ret;
3516 
3517 	if (_ffs_get_single_dev())
3518 			return ERR_PTR(-EBUSY);
3519 
3520 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3521 	if (!dev)
3522 		return ERR_PTR(-ENOMEM);
3523 
3524 	if (list_empty(&ffs_devices)) {
3525 		ret = functionfs_init();
3526 		if (ret) {
3527 			kfree(dev);
3528 			return ERR_PTR(ret);
3529 		}
3530 	}
3531 
3532 	list_add(&dev->entry, &ffs_devices);
3533 
3534 	return dev;
3535 }
3536 
3537 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3538 {
3539 	struct ffs_dev *existing;
3540 	int ret = 0;
3541 
3542 	ffs_dev_lock();
3543 
3544 	existing = _ffs_do_find_dev(name);
3545 	if (!existing)
3546 		strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3547 	else if (existing != dev)
3548 		ret = -EBUSY;
3549 
3550 	ffs_dev_unlock();
3551 
3552 	return ret;
3553 }
3554 EXPORT_SYMBOL_GPL(ffs_name_dev);
3555 
3556 int ffs_single_dev(struct ffs_dev *dev)
3557 {
3558 	int ret;
3559 
3560 	ret = 0;
3561 	ffs_dev_lock();
3562 
3563 	if (!list_is_singular(&ffs_devices))
3564 		ret = -EBUSY;
3565 	else
3566 		dev->single = true;
3567 
3568 	ffs_dev_unlock();
3569 	return ret;
3570 }
3571 EXPORT_SYMBOL_GPL(ffs_single_dev);
3572 
3573 /*
3574  * ffs_lock must be taken by the caller of this function
3575  */
3576 static void _ffs_free_dev(struct ffs_dev *dev)
3577 {
3578 	list_del(&dev->entry);
3579 
3580 	/* Clear the private_data pointer to stop incorrect dev access */
3581 	if (dev->ffs_data)
3582 		dev->ffs_data->private_data = NULL;
3583 
3584 	kfree(dev);
3585 	if (list_empty(&ffs_devices))
3586 		functionfs_cleanup();
3587 }
3588 
3589 static void *ffs_acquire_dev(const char *dev_name)
3590 {
3591 	struct ffs_dev *ffs_dev;
3592 
3593 	ENTER();
3594 	ffs_dev_lock();
3595 
3596 	ffs_dev = _ffs_find_dev(dev_name);
3597 	if (!ffs_dev)
3598 		ffs_dev = ERR_PTR(-ENOENT);
3599 	else if (ffs_dev->mounted)
3600 		ffs_dev = ERR_PTR(-EBUSY);
3601 	else if (ffs_dev->ffs_acquire_dev_callback &&
3602 	    ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3603 		ffs_dev = ERR_PTR(-ENOENT);
3604 	else
3605 		ffs_dev->mounted = true;
3606 
3607 	ffs_dev_unlock();
3608 	return ffs_dev;
3609 }
3610 
3611 static void ffs_release_dev(struct ffs_data *ffs_data)
3612 {
3613 	struct ffs_dev *ffs_dev;
3614 
3615 	ENTER();
3616 	ffs_dev_lock();
3617 
3618 	ffs_dev = ffs_data->private_data;
3619 	if (ffs_dev) {
3620 		ffs_dev->mounted = false;
3621 
3622 		if (ffs_dev->ffs_release_dev_callback)
3623 			ffs_dev->ffs_release_dev_callback(ffs_dev);
3624 	}
3625 
3626 	ffs_dev_unlock();
3627 }
3628 
3629 static int ffs_ready(struct ffs_data *ffs)
3630 {
3631 	struct ffs_dev *ffs_obj;
3632 	int ret = 0;
3633 
3634 	ENTER();
3635 	ffs_dev_lock();
3636 
3637 	ffs_obj = ffs->private_data;
3638 	if (!ffs_obj) {
3639 		ret = -EINVAL;
3640 		goto done;
3641 	}
3642 	if (WARN_ON(ffs_obj->desc_ready)) {
3643 		ret = -EBUSY;
3644 		goto done;
3645 	}
3646 
3647 	ffs_obj->desc_ready = true;
3648 	ffs_obj->ffs_data = ffs;
3649 
3650 	if (ffs_obj->ffs_ready_callback) {
3651 		ret = ffs_obj->ffs_ready_callback(ffs);
3652 		if (ret)
3653 			goto done;
3654 	}
3655 
3656 	set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3657 done:
3658 	ffs_dev_unlock();
3659 	return ret;
3660 }
3661 
3662 static void ffs_closed(struct ffs_data *ffs)
3663 {
3664 	struct ffs_dev *ffs_obj;
3665 	struct f_fs_opts *opts;
3666 	struct config_item *ci;
3667 
3668 	ENTER();
3669 	ffs_dev_lock();
3670 
3671 	ffs_obj = ffs->private_data;
3672 	if (!ffs_obj)
3673 		goto done;
3674 
3675 	ffs_obj->desc_ready = false;
3676 	ffs_obj->ffs_data = NULL;
3677 
3678 	if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3679 	    ffs_obj->ffs_closed_callback)
3680 		ffs_obj->ffs_closed_callback(ffs);
3681 
3682 	if (ffs_obj->opts)
3683 		opts = ffs_obj->opts;
3684 	else
3685 		goto done;
3686 
3687 	if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3688 	    || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3689 		goto done;
3690 
3691 	ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3692 	ffs_dev_unlock();
3693 
3694 	if (test_bit(FFS_FL_BOUND, &ffs->flags))
3695 		unregister_gadget_item(ci);
3696 	return;
3697 done:
3698 	ffs_dev_unlock();
3699 }
3700 
3701 /* Misc helper functions ****************************************************/
3702 
3703 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3704 {
3705 	return nonblock
3706 		? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3707 		: mutex_lock_interruptible(mutex);
3708 }
3709 
3710 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3711 {
3712 	char *data;
3713 
3714 	if (unlikely(!len))
3715 		return NULL;
3716 
3717 	data = kmalloc(len, GFP_KERNEL);
3718 	if (unlikely(!data))
3719 		return ERR_PTR(-ENOMEM);
3720 
3721 	if (unlikely(copy_from_user(data, buf, len))) {
3722 		kfree(data);
3723 		return ERR_PTR(-EFAULT);
3724 	}
3725 
3726 	pr_vdebug("Buffer from user space:\n");
3727 	ffs_dump_mem("", data, len);
3728 
3729 	return data;
3730 }
3731 
3732 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3733 MODULE_LICENSE("GPL");
3734 MODULE_AUTHOR("Michal Nazarewicz");
3735