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1 /*
2 * f_fs.c -- user mode file system API for USB composite function controllers
3 *
4 * Copyright (C) 2010 Samsung Electronics
5 * Author: Michal Nazarewicz <mina86@mina86.com>
6 *
7 * Based on inode.c (GadgetFS) which was:
8 * Copyright (C) 2003-2004 David Brownell
9 * Copyright (C) 2003 Agilent Technologies
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 */
16
17
18 /* #define DEBUG */
19 /* #define VERBOSE_DEBUG */
20
21 #include <linux/blkdev.h>
22 #include <linux/pagemap.h>
23 #include <linux/export.h>
24 #include <linux/hid.h>
25 #include <linux/module.h>
26 #include <linux/sched/signal.h>
27 #include <linux/uio.h>
28 #include <asm/unaligned.h>
29
30 #include <linux/usb/composite.h>
31 #include <linux/usb/functionfs.h>
32
33 #include <linux/aio.h>
34 #include <linux/mmu_context.h>
35 #include <linux/poll.h>
36 #include <linux/eventfd.h>
37
38 #include "u_fs.h"
39 #include "u_f.h"
40 #include "u_os_desc.h"
41 #include "configfs.h"
42
43 #define FUNCTIONFS_MAGIC 0xa647361 /* Chosen by a honest dice roll ;) */
44
45 /* Reference counter handling */
46 static void ffs_data_get(struct ffs_data *ffs);
47 static void ffs_data_put(struct ffs_data *ffs);
48 /* Creates new ffs_data object. */
49 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
50
51 /* Opened counter handling. */
52 static void ffs_data_opened(struct ffs_data *ffs);
53 static void ffs_data_closed(struct ffs_data *ffs);
54
55 /* Called with ffs->mutex held; take over ownership of data. */
56 static int __must_check
57 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
58 static int __must_check
59 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
60
61
62 /* The function structure ***************************************************/
63
64 struct ffs_ep;
65
66 struct ffs_function {
67 struct usb_configuration *conf;
68 struct usb_gadget *gadget;
69 struct ffs_data *ffs;
70
71 struct ffs_ep *eps;
72 u8 eps_revmap[16];
73 short *interfaces_nums;
74
75 struct usb_function function;
76 };
77
78
79 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
80 {
81 return container_of(f, struct ffs_function, function);
82 }
83
84
85 static inline enum ffs_setup_state
86 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
87 {
88 return (enum ffs_setup_state)
89 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
90 }
91
92
93 static void ffs_func_eps_disable(struct ffs_function *func);
94 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
95
96 static int ffs_func_bind(struct usb_configuration *,
97 struct usb_function *);
98 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
99 static void ffs_func_disable(struct usb_function *);
100 static int ffs_func_setup(struct usb_function *,
101 const struct usb_ctrlrequest *);
102 static bool ffs_func_req_match(struct usb_function *,
103 const struct usb_ctrlrequest *,
104 bool config0);
105 static void ffs_func_suspend(struct usb_function *);
106 static void ffs_func_resume(struct usb_function *);
107
108
109 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
110 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
111
112
113 /* The endpoints structures *************************************************/
114
115 struct ffs_ep {
116 struct usb_ep *ep; /* P: ffs->eps_lock */
117 struct usb_request *req; /* P: epfile->mutex */
118
119 /* [0]: full speed, [1]: high speed, [2]: super speed */
120 struct usb_endpoint_descriptor *descs[3];
121
122 u8 num;
123
124 int status; /* P: epfile->mutex */
125 };
126
127 struct ffs_epfile {
128 /* Protects ep->ep and ep->req. */
129 struct mutex mutex;
130 wait_queue_head_t wait;
131
132 struct ffs_data *ffs;
133 struct ffs_ep *ep; /* P: ffs->eps_lock */
134
135 struct dentry *dentry;
136
137 /*
138 * Buffer for holding data from partial reads which may happen since
139 * we’re rounding user read requests to a multiple of a max packet size.
140 *
141 * The pointer is initialised with NULL value and may be set by
142 * __ffs_epfile_read_data function to point to a temporary buffer.
143 *
144 * In normal operation, calls to __ffs_epfile_read_buffered will consume
145 * data from said buffer and eventually free it. Importantly, while the
146 * function is using the buffer, it sets the pointer to NULL. This is
147 * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
148 * can never run concurrently (they are synchronised by epfile->mutex)
149 * so the latter will not assign a new value to the pointer.
150 *
151 * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
152 * valid) and sets the pointer to READ_BUFFER_DROP value. This special
153 * value is crux of the synchronisation between ffs_func_eps_disable and
154 * __ffs_epfile_read_data.
155 *
156 * Once __ffs_epfile_read_data is about to finish it will try to set the
157 * pointer back to its old value (as described above), but seeing as the
158 * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
159 * the buffer.
160 *
161 * == State transitions ==
162 *
163 * • ptr == NULL: (initial state)
164 * ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
165 * ◦ __ffs_epfile_read_buffered: nop
166 * ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
167 * ◦ reading finishes: n/a, not in ‘and reading’ state
168 * • ptr == DROP:
169 * ◦ __ffs_epfile_read_buffer_free: nop
170 * ◦ __ffs_epfile_read_buffered: go to ptr == NULL
171 * ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
172 * ◦ reading finishes: n/a, not in ‘and reading’ state
173 * • ptr == buf:
174 * ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
175 * ◦ __ffs_epfile_read_buffered: go to ptr == NULL and reading
176 * ◦ __ffs_epfile_read_data: n/a, __ffs_epfile_read_buffered
177 * is always called first
178 * ◦ reading finishes: n/a, not in ‘and reading’ state
179 * • ptr == NULL and reading:
180 * ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
181 * ◦ __ffs_epfile_read_buffered: n/a, mutex is held
182 * ◦ __ffs_epfile_read_data: n/a, mutex is held
183 * ◦ reading finishes and …
184 * … all data read: free buf, go to ptr == NULL
185 * … otherwise: go to ptr == buf and reading
186 * • ptr == DROP and reading:
187 * ◦ __ffs_epfile_read_buffer_free: nop
188 * ◦ __ffs_epfile_read_buffered: n/a, mutex is held
189 * ◦ __ffs_epfile_read_data: n/a, mutex is held
190 * ◦ reading finishes: free buf, go to ptr == DROP
191 */
192 struct ffs_buffer *read_buffer;
193 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
194
195 char name[5];
196
197 unsigned char in; /* P: ffs->eps_lock */
198 unsigned char isoc; /* P: ffs->eps_lock */
199
200 unsigned char _pad;
201 };
202
203 struct ffs_buffer {
204 size_t length;
205 char *data;
206 char storage[];
207 };
208
209 /* ffs_io_data structure ***************************************************/
210
211 struct ffs_io_data {
212 bool aio;
213 bool read;
214
215 struct kiocb *kiocb;
216 struct iov_iter data;
217 const void *to_free;
218 char *buf;
219
220 struct mm_struct *mm;
221 struct work_struct work;
222
223 struct usb_ep *ep;
224 struct usb_request *req;
225
226 struct ffs_data *ffs;
227 };
228
229 struct ffs_desc_helper {
230 struct ffs_data *ffs;
231 unsigned interfaces_count;
232 unsigned eps_count;
233 };
234
235 static int __must_check ffs_epfiles_create(struct ffs_data *ffs);
236 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
237
238 static struct dentry *
239 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
240 const struct file_operations *fops);
241
242 /* Devices management *******************************************************/
243
244 DEFINE_MUTEX(ffs_lock);
245 EXPORT_SYMBOL_GPL(ffs_lock);
246
247 static struct ffs_dev *_ffs_find_dev(const char *name);
248 static struct ffs_dev *_ffs_alloc_dev(void);
249 static int _ffs_name_dev(struct ffs_dev *dev, const char *name);
250 static void _ffs_free_dev(struct ffs_dev *dev);
251 static void *ffs_acquire_dev(const char *dev_name);
252 static void ffs_release_dev(struct ffs_data *ffs_data);
253 static int ffs_ready(struct ffs_data *ffs);
254 static void ffs_closed(struct ffs_data *ffs);
255
256 /* Misc helper functions ****************************************************/
257
258 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
259 __attribute__((warn_unused_result, nonnull));
260 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
261 __attribute__((warn_unused_result, nonnull));
262
263
264 /* Control file aka ep0 *****************************************************/
265
266 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
267 {
268 struct ffs_data *ffs = req->context;
269
270 complete(&ffs->ep0req_completion);
271 }
272
273 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
274 {
275 struct usb_request *req = ffs->ep0req;
276 int ret;
277
278 req->zero = len < le16_to_cpu(ffs->ev.setup.wLength);
279
280 spin_unlock_irq(&ffs->ev.waitq.lock);
281
282 req->buf = data;
283 req->length = len;
284
285 /*
286 * UDC layer requires to provide a buffer even for ZLP, but should
287 * not use it at all. Let's provide some poisoned pointer to catch
288 * possible bug in the driver.
289 */
290 if (req->buf == NULL)
291 req->buf = (void *)0xDEADBABE;
292
293 reinit_completion(&ffs->ep0req_completion);
294
295 ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
296 if (unlikely(ret < 0))
297 return ret;
298
299 ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
300 if (unlikely(ret)) {
301 usb_ep_dequeue(ffs->gadget->ep0, req);
302 return -EINTR;
303 }
304
305 ffs->setup_state = FFS_NO_SETUP;
306 return req->status ? req->status : req->actual;
307 }
308
309 static int __ffs_ep0_stall(struct ffs_data *ffs)
310 {
311 if (ffs->ev.can_stall) {
312 pr_vdebug("ep0 stall\n");
313 usb_ep_set_halt(ffs->gadget->ep0);
314 ffs->setup_state = FFS_NO_SETUP;
315 return -EL2HLT;
316 } else {
317 pr_debug("bogus ep0 stall!\n");
318 return -ESRCH;
319 }
320 }
321
322 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
323 size_t len, loff_t *ptr)
324 {
325 struct ffs_data *ffs = file->private_data;
326 ssize_t ret;
327 char *data;
328
329 ENTER();
330
331 /* Fast check if setup was canceled */
332 if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
333 return -EIDRM;
334
335 /* Acquire mutex */
336 ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
337 if (unlikely(ret < 0))
338 return ret;
339
340 /* Check state */
341 switch (ffs->state) {
342 case FFS_READ_DESCRIPTORS:
343 case FFS_READ_STRINGS:
344 /* Copy data */
345 if (unlikely(len < 16)) {
346 ret = -EINVAL;
347 break;
348 }
349
350 data = ffs_prepare_buffer(buf, len);
351 if (IS_ERR(data)) {
352 ret = PTR_ERR(data);
353 break;
354 }
355
356 /* Handle data */
357 if (ffs->state == FFS_READ_DESCRIPTORS) {
358 pr_info("read descriptors\n");
359 ret = __ffs_data_got_descs(ffs, data, len);
360 if (unlikely(ret < 0))
361 break;
362
363 ffs->state = FFS_READ_STRINGS;
364 ret = len;
365 } else {
366 pr_info("read strings\n");
367 ret = __ffs_data_got_strings(ffs, data, len);
368 if (unlikely(ret < 0))
369 break;
370
371 ret = ffs_epfiles_create(ffs);
372 if (unlikely(ret)) {
373 ffs->state = FFS_CLOSING;
374 break;
375 }
376
377 ffs->state = FFS_ACTIVE;
378 mutex_unlock(&ffs->mutex);
379
380 ret = ffs_ready(ffs);
381 if (unlikely(ret < 0)) {
382 ffs->state = FFS_CLOSING;
383 return ret;
384 }
385
386 return len;
387 }
388 break;
389
390 case FFS_ACTIVE:
391 data = NULL;
392 /*
393 * We're called from user space, we can use _irq
394 * rather then _irqsave
395 */
396 spin_lock_irq(&ffs->ev.waitq.lock);
397 switch (ffs_setup_state_clear_cancelled(ffs)) {
398 case FFS_SETUP_CANCELLED:
399 ret = -EIDRM;
400 goto done_spin;
401
402 case FFS_NO_SETUP:
403 ret = -ESRCH;
404 goto done_spin;
405
406 case FFS_SETUP_PENDING:
407 break;
408 }
409
410 /* FFS_SETUP_PENDING */
411 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
412 spin_unlock_irq(&ffs->ev.waitq.lock);
413 ret = __ffs_ep0_stall(ffs);
414 break;
415 }
416
417 /* FFS_SETUP_PENDING and not stall */
418 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
419
420 spin_unlock_irq(&ffs->ev.waitq.lock);
421
422 data = ffs_prepare_buffer(buf, len);
423 if (IS_ERR(data)) {
424 ret = PTR_ERR(data);
425 break;
426 }
427
428 spin_lock_irq(&ffs->ev.waitq.lock);
429
430 /*
431 * We are guaranteed to be still in FFS_ACTIVE state
432 * but the state of setup could have changed from
433 * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
434 * to check for that. If that happened we copied data
435 * from user space in vain but it's unlikely.
436 *
437 * For sure we are not in FFS_NO_SETUP since this is
438 * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
439 * transition can be performed and it's protected by
440 * mutex.
441 */
442 if (ffs_setup_state_clear_cancelled(ffs) ==
443 FFS_SETUP_CANCELLED) {
444 ret = -EIDRM;
445 done_spin:
446 spin_unlock_irq(&ffs->ev.waitq.lock);
447 } else {
448 /* unlocks spinlock */
449 ret = __ffs_ep0_queue_wait(ffs, data, len);
450 }
451 kfree(data);
452 break;
453
454 default:
455 ret = -EBADFD;
456 break;
457 }
458
459 mutex_unlock(&ffs->mutex);
460 return ret;
461 }
462
463 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
464 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
465 size_t n)
466 {
467 /*
468 * n cannot be bigger than ffs->ev.count, which cannot be bigger than
469 * size of ffs->ev.types array (which is four) so that's how much space
470 * we reserve.
471 */
472 struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
473 const size_t size = n * sizeof *events;
474 unsigned i = 0;
475
476 memset(events, 0, size);
477
478 do {
479 events[i].type = ffs->ev.types[i];
480 if (events[i].type == FUNCTIONFS_SETUP) {
481 events[i].u.setup = ffs->ev.setup;
482 ffs->setup_state = FFS_SETUP_PENDING;
483 }
484 } while (++i < n);
485
486 ffs->ev.count -= n;
487 if (ffs->ev.count)
488 memmove(ffs->ev.types, ffs->ev.types + n,
489 ffs->ev.count * sizeof *ffs->ev.types);
490
491 spin_unlock_irq(&ffs->ev.waitq.lock);
492 mutex_unlock(&ffs->mutex);
493
494 return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
495 }
496
497 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
498 size_t len, loff_t *ptr)
499 {
500 struct ffs_data *ffs = file->private_data;
501 char *data = NULL;
502 size_t n;
503 int ret;
504
505 ENTER();
506
507 /* Fast check if setup was canceled */
508 if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
509 return -EIDRM;
510
511 /* Acquire mutex */
512 ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
513 if (unlikely(ret < 0))
514 return ret;
515
516 /* Check state */
517 if (ffs->state != FFS_ACTIVE) {
518 ret = -EBADFD;
519 goto done_mutex;
520 }
521
522 /*
523 * We're called from user space, we can use _irq rather then
524 * _irqsave
525 */
526 spin_lock_irq(&ffs->ev.waitq.lock);
527
528 switch (ffs_setup_state_clear_cancelled(ffs)) {
529 case FFS_SETUP_CANCELLED:
530 ret = -EIDRM;
531 break;
532
533 case FFS_NO_SETUP:
534 n = len / sizeof(struct usb_functionfs_event);
535 if (unlikely(!n)) {
536 ret = -EINVAL;
537 break;
538 }
539
540 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
541 ret = -EAGAIN;
542 break;
543 }
544
545 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
546 ffs->ev.count)) {
547 ret = -EINTR;
548 break;
549 }
550
551 return __ffs_ep0_read_events(ffs, buf,
552 min(n, (size_t)ffs->ev.count));
553
554 case FFS_SETUP_PENDING:
555 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
556 spin_unlock_irq(&ffs->ev.waitq.lock);
557 ret = __ffs_ep0_stall(ffs);
558 goto done_mutex;
559 }
560
561 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
562
563 spin_unlock_irq(&ffs->ev.waitq.lock);
564
565 if (likely(len)) {
566 data = kmalloc(len, GFP_KERNEL);
567 if (unlikely(!data)) {
568 ret = -ENOMEM;
569 goto done_mutex;
570 }
571 }
572
573 spin_lock_irq(&ffs->ev.waitq.lock);
574
575 /* See ffs_ep0_write() */
576 if (ffs_setup_state_clear_cancelled(ffs) ==
577 FFS_SETUP_CANCELLED) {
578 ret = -EIDRM;
579 break;
580 }
581
582 /* unlocks spinlock */
583 ret = __ffs_ep0_queue_wait(ffs, data, len);
584 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
585 ret = -EFAULT;
586 goto done_mutex;
587
588 default:
589 ret = -EBADFD;
590 break;
591 }
592
593 spin_unlock_irq(&ffs->ev.waitq.lock);
594 done_mutex:
595 mutex_unlock(&ffs->mutex);
596 kfree(data);
597 return ret;
598 }
599
600 static int ffs_ep0_open(struct inode *inode, struct file *file)
601 {
602 struct ffs_data *ffs = inode->i_private;
603
604 ENTER();
605
606 if (unlikely(ffs->state == FFS_CLOSING))
607 return -EBUSY;
608
609 file->private_data = ffs;
610 ffs_data_opened(ffs);
611
612 return 0;
613 }
614
615 static int ffs_ep0_release(struct inode *inode, struct file *file)
616 {
617 struct ffs_data *ffs = file->private_data;
618
619 ENTER();
620
621 ffs_data_closed(ffs);
622
623 return 0;
624 }
625
626 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
627 {
628 struct ffs_data *ffs = file->private_data;
629 struct usb_gadget *gadget = ffs->gadget;
630 long ret;
631
632 ENTER();
633
634 if (code == FUNCTIONFS_INTERFACE_REVMAP) {
635 struct ffs_function *func = ffs->func;
636 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
637 } else if (gadget && gadget->ops->ioctl) {
638 ret = gadget->ops->ioctl(gadget, code, value);
639 } else {
640 ret = -ENOTTY;
641 }
642
643 return ret;
644 }
645
646 static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
647 {
648 struct ffs_data *ffs = file->private_data;
649 unsigned int mask = POLLWRNORM;
650 int ret;
651
652 poll_wait(file, &ffs->ev.waitq, wait);
653
654 ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
655 if (unlikely(ret < 0))
656 return mask;
657
658 switch (ffs->state) {
659 case FFS_READ_DESCRIPTORS:
660 case FFS_READ_STRINGS:
661 mask |= POLLOUT;
662 break;
663
664 case FFS_ACTIVE:
665 switch (ffs->setup_state) {
666 case FFS_NO_SETUP:
667 if (ffs->ev.count)
668 mask |= POLLIN;
669 break;
670
671 case FFS_SETUP_PENDING:
672 case FFS_SETUP_CANCELLED:
673 mask |= (POLLIN | POLLOUT);
674 break;
675 }
676 case FFS_CLOSING:
677 break;
678 case FFS_DEACTIVATED:
679 break;
680 }
681
682 mutex_unlock(&ffs->mutex);
683
684 return mask;
685 }
686
687 static const struct file_operations ffs_ep0_operations = {
688 .llseek = no_llseek,
689
690 .open = ffs_ep0_open,
691 .write = ffs_ep0_write,
692 .read = ffs_ep0_read,
693 .release = ffs_ep0_release,
694 .unlocked_ioctl = ffs_ep0_ioctl,
695 .poll = ffs_ep0_poll,
696 };
697
698
699 /* "Normal" endpoints operations ********************************************/
700
701 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
702 {
703 ENTER();
704 if (likely(req->context)) {
705 struct ffs_ep *ep = _ep->driver_data;
706 ep->status = req->status ? req->status : req->actual;
707 complete(req->context);
708 }
709 }
710
711 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
712 {
713 ssize_t ret = copy_to_iter(data, data_len, iter);
714 if (likely(ret == data_len))
715 return ret;
716
717 if (unlikely(iov_iter_count(iter)))
718 return -EFAULT;
719
720 /*
721 * Dear user space developer!
722 *
723 * TL;DR: To stop getting below error message in your kernel log, change
724 * user space code using functionfs to align read buffers to a max
725 * packet size.
726 *
727 * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
728 * packet size. When unaligned buffer is passed to functionfs, it
729 * internally uses a larger, aligned buffer so that such UDCs are happy.
730 *
731 * Unfortunately, this means that host may send more data than was
732 * requested in read(2) system call. f_fs doesn’t know what to do with
733 * that excess data so it simply drops it.
734 *
735 * Was the buffer aligned in the first place, no such problem would
736 * happen.
737 *
738 * Data may be dropped only in AIO reads. Synchronous reads are handled
739 * by splitting a request into multiple parts. This splitting may still
740 * be a problem though so it’s likely best to align the buffer
741 * regardless of it being AIO or not..
742 *
743 * This only affects OUT endpoints, i.e. reading data with a read(2),
744 * aio_read(2) etc. system calls. Writing data to an IN endpoint is not
745 * affected.
746 */
747 pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
748 "Align read buffer size to max packet size to avoid the problem.\n",
749 data_len, ret);
750
751 return ret;
752 }
753
754 static void ffs_user_copy_worker(struct work_struct *work)
755 {
756 struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
757 work);
758 int ret = io_data->req->status ? io_data->req->status :
759 io_data->req->actual;
760 bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
761
762 if (io_data->read && ret > 0) {
763 use_mm(io_data->mm);
764 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
765 unuse_mm(io_data->mm);
766 }
767
768 io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
769
770 if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
771 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
772
773 usb_ep_free_request(io_data->ep, io_data->req);
774
775 if (io_data->read)
776 kfree(io_data->to_free);
777 kfree(io_data->buf);
778 kfree(io_data);
779 }
780
781 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
782 struct usb_request *req)
783 {
784 struct ffs_io_data *io_data = req->context;
785
786 ENTER();
787
788 INIT_WORK(&io_data->work, ffs_user_copy_worker);
789 schedule_work(&io_data->work);
790 }
791
792 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
793 {
794 /*
795 * See comment in struct ffs_epfile for full read_buffer pointer
796 * synchronisation story.
797 */
798 struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
799 if (buf && buf != READ_BUFFER_DROP)
800 kfree(buf);
801 }
802
803 /* Assumes epfile->mutex is held. */
804 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
805 struct iov_iter *iter)
806 {
807 /*
808 * Null out epfile->read_buffer so ffs_func_eps_disable does not free
809 * the buffer while we are using it. See comment in struct ffs_epfile
810 * for full read_buffer pointer synchronisation story.
811 */
812 struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
813 ssize_t ret;
814 if (!buf || buf == READ_BUFFER_DROP)
815 return 0;
816
817 ret = copy_to_iter(buf->data, buf->length, iter);
818 if (buf->length == ret) {
819 kfree(buf);
820 return ret;
821 }
822
823 if (unlikely(iov_iter_count(iter))) {
824 ret = -EFAULT;
825 } else {
826 buf->length -= ret;
827 buf->data += ret;
828 }
829
830 if (cmpxchg(&epfile->read_buffer, NULL, buf))
831 kfree(buf);
832
833 return ret;
834 }
835
836 /* Assumes epfile->mutex is held. */
837 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
838 void *data, int data_len,
839 struct iov_iter *iter)
840 {
841 struct ffs_buffer *buf;
842
843 ssize_t ret = copy_to_iter(data, data_len, iter);
844 if (likely(data_len == ret))
845 return ret;
846
847 if (unlikely(iov_iter_count(iter)))
848 return -EFAULT;
849
850 /* See ffs_copy_to_iter for more context. */
851 pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
852 data_len, ret);
853
854 data_len -= ret;
855 buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
856 if (!buf)
857 return -ENOMEM;
858 buf->length = data_len;
859 buf->data = buf->storage;
860 memcpy(buf->storage, data + ret, data_len);
861
862 /*
863 * At this point read_buffer is NULL or READ_BUFFER_DROP (if
864 * ffs_func_eps_disable has been called in the meanwhile). See comment
865 * in struct ffs_epfile for full read_buffer pointer synchronisation
866 * story.
867 */
868 if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
869 kfree(buf);
870
871 return ret;
872 }
873
874 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
875 {
876 struct ffs_epfile *epfile = file->private_data;
877 struct usb_request *req;
878 struct ffs_ep *ep;
879 char *data = NULL;
880 ssize_t ret, data_len = -EINVAL;
881 int halt;
882
883 /* Are we still active? */
884 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
885 return -ENODEV;
886
887 /* Wait for endpoint to be enabled */
888 ep = epfile->ep;
889 if (!ep) {
890 if (file->f_flags & O_NONBLOCK)
891 return -EAGAIN;
892
893 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
894 if (ret)
895 return -EINTR;
896 }
897
898 /* Do we halt? */
899 halt = (!io_data->read == !epfile->in);
900 if (halt && epfile->isoc)
901 return -EINVAL;
902
903 /* We will be using request and read_buffer */
904 ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
905 if (unlikely(ret))
906 goto error;
907
908 /* Allocate & copy */
909 if (!halt) {
910 struct usb_gadget *gadget;
911
912 /*
913 * Do we have buffered data from previous partial read? Check
914 * that for synchronous case only because we do not have
915 * facility to ‘wake up’ a pending asynchronous read and push
916 * buffered data to it which we would need to make things behave
917 * consistently.
918 */
919 if (!io_data->aio && io_data->read) {
920 ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
921 if (ret)
922 goto error_mutex;
923 }
924
925 /*
926 * if we _do_ wait above, the epfile->ffs->gadget might be NULL
927 * before the waiting completes, so do not assign to 'gadget'
928 * earlier
929 */
930 gadget = epfile->ffs->gadget;
931
932 spin_lock_irq(&epfile->ffs->eps_lock);
933 /* In the meantime, endpoint got disabled or changed. */
934 if (epfile->ep != ep) {
935 ret = -ESHUTDOWN;
936 goto error_lock;
937 }
938 data_len = iov_iter_count(&io_data->data);
939 /*
940 * Controller may require buffer size to be aligned to
941 * maxpacketsize of an out endpoint.
942 */
943 if (io_data->read)
944 data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
945 spin_unlock_irq(&epfile->ffs->eps_lock);
946
947 data = kmalloc(data_len, GFP_KERNEL);
948 if (unlikely(!data)) {
949 ret = -ENOMEM;
950 goto error_mutex;
951 }
952 if (!io_data->read &&
953 !copy_from_iter_full(data, data_len, &io_data->data)) {
954 ret = -EFAULT;
955 goto error_mutex;
956 }
957 }
958
959 spin_lock_irq(&epfile->ffs->eps_lock);
960
961 if (epfile->ep != ep) {
962 /* In the meantime, endpoint got disabled or changed. */
963 ret = -ESHUTDOWN;
964 } else if (halt) {
965 /* Halt */
966 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
967 usb_ep_set_halt(ep->ep);
968 ret = -EBADMSG;
969 } else if (unlikely(data_len == -EINVAL)) {
970 /*
971 * Sanity Check: even though data_len can't be used
972 * uninitialized at the time I write this comment, some
973 * compilers complain about this situation.
974 * In order to keep the code clean from warnings, data_len is
975 * being initialized to -EINVAL during its declaration, which
976 * means we can't rely on compiler anymore to warn no future
977 * changes won't result in data_len being used uninitialized.
978 * For such reason, we're adding this redundant sanity check
979 * here.
980 */
981 WARN(1, "%s: data_len == -EINVAL\n", __func__);
982 ret = -EINVAL;
983 } else if (!io_data->aio) {
984 DECLARE_COMPLETION_ONSTACK(done);
985 bool interrupted = false;
986
987 req = ep->req;
988 req->buf = data;
989 req->length = data_len;
990
991 req->context = &done;
992 req->complete = ffs_epfile_io_complete;
993
994 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
995 if (unlikely(ret < 0))
996 goto error_lock;
997
998 spin_unlock_irq(&epfile->ffs->eps_lock);
999
1000 if (unlikely(wait_for_completion_interruptible(&done))) {
1001 /*
1002 * To avoid race condition with ffs_epfile_io_complete,
1003 * dequeue the request first then check
1004 * status. usb_ep_dequeue API should guarantee no race
1005 * condition with req->complete callback.
1006 */
1007 usb_ep_dequeue(ep->ep, req);
1008 interrupted = ep->status < 0;
1009 }
1010
1011 if (interrupted)
1012 ret = -EINTR;
1013 else if (io_data->read && ep->status > 0)
1014 ret = __ffs_epfile_read_data(epfile, data, ep->status,
1015 &io_data->data);
1016 else
1017 ret = ep->status;
1018 goto error_mutex;
1019 } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_KERNEL))) {
1020 ret = -ENOMEM;
1021 } else {
1022 req->buf = data;
1023 req->length = data_len;
1024
1025 io_data->buf = data;
1026 io_data->ep = ep->ep;
1027 io_data->req = req;
1028 io_data->ffs = epfile->ffs;
1029
1030 req->context = io_data;
1031 req->complete = ffs_epfile_async_io_complete;
1032
1033 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1034 if (unlikely(ret)) {
1035 usb_ep_free_request(ep->ep, req);
1036 goto error_lock;
1037 }
1038
1039 ret = -EIOCBQUEUED;
1040 /*
1041 * Do not kfree the buffer in this function. It will be freed
1042 * by ffs_user_copy_worker.
1043 */
1044 data = NULL;
1045 }
1046
1047 error_lock:
1048 spin_unlock_irq(&epfile->ffs->eps_lock);
1049 error_mutex:
1050 mutex_unlock(&epfile->mutex);
1051 error:
1052 kfree(data);
1053 return ret;
1054 }
1055
1056 static int
1057 ffs_epfile_open(struct inode *inode, struct file *file)
1058 {
1059 struct ffs_epfile *epfile = inode->i_private;
1060
1061 ENTER();
1062
1063 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1064 return -ENODEV;
1065
1066 file->private_data = epfile;
1067 ffs_data_opened(epfile->ffs);
1068
1069 return 0;
1070 }
1071
1072 static int ffs_aio_cancel(struct kiocb *kiocb)
1073 {
1074 struct ffs_io_data *io_data = kiocb->private;
1075 struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1076 int value;
1077
1078 ENTER();
1079
1080 spin_lock_irq(&epfile->ffs->eps_lock);
1081
1082 if (likely(io_data && io_data->ep && io_data->req))
1083 value = usb_ep_dequeue(io_data->ep, io_data->req);
1084 else
1085 value = -EINVAL;
1086
1087 spin_unlock_irq(&epfile->ffs->eps_lock);
1088
1089 return value;
1090 }
1091
1092 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1093 {
1094 struct ffs_io_data io_data, *p = &io_data;
1095 ssize_t res;
1096
1097 ENTER();
1098
1099 if (!is_sync_kiocb(kiocb)) {
1100 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1101 if (unlikely(!p))
1102 return -ENOMEM;
1103 p->aio = true;
1104 } else {
1105 p->aio = false;
1106 }
1107
1108 p->read = false;
1109 p->kiocb = kiocb;
1110 p->data = *from;
1111 p->mm = current->mm;
1112
1113 kiocb->private = p;
1114
1115 if (p->aio)
1116 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1117
1118 res = ffs_epfile_io(kiocb->ki_filp, p);
1119 if (res == -EIOCBQUEUED)
1120 return res;
1121 if (p->aio)
1122 kfree(p);
1123 else
1124 *from = p->data;
1125 return res;
1126 }
1127
1128 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1129 {
1130 struct ffs_io_data io_data, *p = &io_data;
1131 ssize_t res;
1132
1133 ENTER();
1134
1135 if (!is_sync_kiocb(kiocb)) {
1136 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1137 if (unlikely(!p))
1138 return -ENOMEM;
1139 p->aio = true;
1140 } else {
1141 p->aio = false;
1142 }
1143
1144 p->read = true;
1145 p->kiocb = kiocb;
1146 if (p->aio) {
1147 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1148 if (!p->to_free) {
1149 kfree(p);
1150 return -ENOMEM;
1151 }
1152 } else {
1153 p->data = *to;
1154 p->to_free = NULL;
1155 }
1156 p->mm = current->mm;
1157
1158 kiocb->private = p;
1159
1160 if (p->aio)
1161 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1162
1163 res = ffs_epfile_io(kiocb->ki_filp, p);
1164 if (res == -EIOCBQUEUED)
1165 return res;
1166
1167 if (p->aio) {
1168 kfree(p->to_free);
1169 kfree(p);
1170 } else {
1171 *to = p->data;
1172 }
1173 return res;
1174 }
1175
1176 static int
1177 ffs_epfile_release(struct inode *inode, struct file *file)
1178 {
1179 struct ffs_epfile *epfile = inode->i_private;
1180
1181 ENTER();
1182
1183 __ffs_epfile_read_buffer_free(epfile);
1184 ffs_data_closed(epfile->ffs);
1185
1186 return 0;
1187 }
1188
1189 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1190 unsigned long value)
1191 {
1192 struct ffs_epfile *epfile = file->private_data;
1193 int ret;
1194
1195 ENTER();
1196
1197 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1198 return -ENODEV;
1199
1200 spin_lock_irq(&epfile->ffs->eps_lock);
1201 if (likely(epfile->ep)) {
1202 switch (code) {
1203 case FUNCTIONFS_FIFO_STATUS:
1204 ret = usb_ep_fifo_status(epfile->ep->ep);
1205 break;
1206 case FUNCTIONFS_FIFO_FLUSH:
1207 usb_ep_fifo_flush(epfile->ep->ep);
1208 ret = 0;
1209 break;
1210 case FUNCTIONFS_CLEAR_HALT:
1211 ret = usb_ep_clear_halt(epfile->ep->ep);
1212 break;
1213 case FUNCTIONFS_ENDPOINT_REVMAP:
1214 ret = epfile->ep->num;
1215 break;
1216 case FUNCTIONFS_ENDPOINT_DESC:
1217 {
1218 int desc_idx;
1219 struct usb_endpoint_descriptor *desc;
1220
1221 switch (epfile->ffs->gadget->speed) {
1222 case USB_SPEED_SUPER:
1223 desc_idx = 2;
1224 break;
1225 case USB_SPEED_HIGH:
1226 desc_idx = 1;
1227 break;
1228 default:
1229 desc_idx = 0;
1230 }
1231 desc = epfile->ep->descs[desc_idx];
1232
1233 spin_unlock_irq(&epfile->ffs->eps_lock);
1234 ret = copy_to_user((void *)value, desc, desc->bLength);
1235 if (ret)
1236 ret = -EFAULT;
1237 return ret;
1238 }
1239 default:
1240 ret = -ENOTTY;
1241 }
1242 } else {
1243 ret = -ENODEV;
1244 }
1245 spin_unlock_irq(&epfile->ffs->eps_lock);
1246
1247 return ret;
1248 }
1249
1250 static const struct file_operations ffs_epfile_operations = {
1251 .llseek = no_llseek,
1252
1253 .open = ffs_epfile_open,
1254 .write_iter = ffs_epfile_write_iter,
1255 .read_iter = ffs_epfile_read_iter,
1256 .release = ffs_epfile_release,
1257 .unlocked_ioctl = ffs_epfile_ioctl,
1258 };
1259
1260
1261 /* File system and super block operations ***********************************/
1262
1263 /*
1264 * Mounting the file system creates a controller file, used first for
1265 * function configuration then later for event monitoring.
1266 */
1267
1268 static struct inode *__must_check
1269 ffs_sb_make_inode(struct super_block *sb, void *data,
1270 const struct file_operations *fops,
1271 const struct inode_operations *iops,
1272 struct ffs_file_perms *perms)
1273 {
1274 struct inode *inode;
1275
1276 ENTER();
1277
1278 inode = new_inode(sb);
1279
1280 if (likely(inode)) {
1281 struct timespec ts = current_time(inode);
1282
1283 inode->i_ino = get_next_ino();
1284 inode->i_mode = perms->mode;
1285 inode->i_uid = perms->uid;
1286 inode->i_gid = perms->gid;
1287 inode->i_atime = ts;
1288 inode->i_mtime = ts;
1289 inode->i_ctime = ts;
1290 inode->i_private = data;
1291 if (fops)
1292 inode->i_fop = fops;
1293 if (iops)
1294 inode->i_op = iops;
1295 }
1296
1297 return inode;
1298 }
1299
1300 /* Create "regular" file */
1301 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1302 const char *name, void *data,
1303 const struct file_operations *fops)
1304 {
1305 struct ffs_data *ffs = sb->s_fs_info;
1306 struct dentry *dentry;
1307 struct inode *inode;
1308
1309 ENTER();
1310
1311 dentry = d_alloc_name(sb->s_root, name);
1312 if (unlikely(!dentry))
1313 return NULL;
1314
1315 inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1316 if (unlikely(!inode)) {
1317 dput(dentry);
1318 return NULL;
1319 }
1320
1321 d_add(dentry, inode);
1322 return dentry;
1323 }
1324
1325 /* Super block */
1326 static const struct super_operations ffs_sb_operations = {
1327 .statfs = simple_statfs,
1328 .drop_inode = generic_delete_inode,
1329 };
1330
1331 struct ffs_sb_fill_data {
1332 struct ffs_file_perms perms;
1333 umode_t root_mode;
1334 const char *dev_name;
1335 bool no_disconnect;
1336 struct ffs_data *ffs_data;
1337 };
1338
1339 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1340 {
1341 struct ffs_sb_fill_data *data = _data;
1342 struct inode *inode;
1343 struct ffs_data *ffs = data->ffs_data;
1344
1345 ENTER();
1346
1347 ffs->sb = sb;
1348 data->ffs_data = NULL;
1349 sb->s_fs_info = ffs;
1350 sb->s_blocksize = PAGE_SIZE;
1351 sb->s_blocksize_bits = PAGE_SHIFT;
1352 sb->s_magic = FUNCTIONFS_MAGIC;
1353 sb->s_op = &ffs_sb_operations;
1354 sb->s_time_gran = 1;
1355
1356 /* Root inode */
1357 data->perms.mode = data->root_mode;
1358 inode = ffs_sb_make_inode(sb, NULL,
1359 &simple_dir_operations,
1360 &simple_dir_inode_operations,
1361 &data->perms);
1362 sb->s_root = d_make_root(inode);
1363 if (unlikely(!sb->s_root))
1364 return -ENOMEM;
1365
1366 /* EP0 file */
1367 if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1368 &ffs_ep0_operations)))
1369 return -ENOMEM;
1370
1371 return 0;
1372 }
1373
1374 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1375 {
1376 ENTER();
1377
1378 if (!opts || !*opts)
1379 return 0;
1380
1381 for (;;) {
1382 unsigned long value;
1383 char *eq, *comma;
1384
1385 /* Option limit */
1386 comma = strchr(opts, ',');
1387 if (comma)
1388 *comma = 0;
1389
1390 /* Value limit */
1391 eq = strchr(opts, '=');
1392 if (unlikely(!eq)) {
1393 pr_err("'=' missing in %s\n", opts);
1394 return -EINVAL;
1395 }
1396 *eq = 0;
1397
1398 /* Parse value */
1399 if (kstrtoul(eq + 1, 0, &value)) {
1400 pr_err("%s: invalid value: %s\n", opts, eq + 1);
1401 return -EINVAL;
1402 }
1403
1404 /* Interpret option */
1405 switch (eq - opts) {
1406 case 13:
1407 if (!memcmp(opts, "no_disconnect", 13))
1408 data->no_disconnect = !!value;
1409 else
1410 goto invalid;
1411 break;
1412 case 5:
1413 if (!memcmp(opts, "rmode", 5))
1414 data->root_mode = (value & 0555) | S_IFDIR;
1415 else if (!memcmp(opts, "fmode", 5))
1416 data->perms.mode = (value & 0666) | S_IFREG;
1417 else
1418 goto invalid;
1419 break;
1420
1421 case 4:
1422 if (!memcmp(opts, "mode", 4)) {
1423 data->root_mode = (value & 0555) | S_IFDIR;
1424 data->perms.mode = (value & 0666) | S_IFREG;
1425 } else {
1426 goto invalid;
1427 }
1428 break;
1429
1430 case 3:
1431 if (!memcmp(opts, "uid", 3)) {
1432 data->perms.uid = make_kuid(current_user_ns(), value);
1433 if (!uid_valid(data->perms.uid)) {
1434 pr_err("%s: unmapped value: %lu\n", opts, value);
1435 return -EINVAL;
1436 }
1437 } else if (!memcmp(opts, "gid", 3)) {
1438 data->perms.gid = make_kgid(current_user_ns(), value);
1439 if (!gid_valid(data->perms.gid)) {
1440 pr_err("%s: unmapped value: %lu\n", opts, value);
1441 return -EINVAL;
1442 }
1443 } else {
1444 goto invalid;
1445 }
1446 break;
1447
1448 default:
1449 invalid:
1450 pr_err("%s: invalid option\n", opts);
1451 return -EINVAL;
1452 }
1453
1454 /* Next iteration */
1455 if (!comma)
1456 break;
1457 opts = comma + 1;
1458 }
1459
1460 return 0;
1461 }
1462
1463 /* "mount -t functionfs dev_name /dev/function" ends up here */
1464
1465 static struct dentry *
1466 ffs_fs_mount(struct file_system_type *t, int flags,
1467 const char *dev_name, void *opts)
1468 {
1469 struct ffs_sb_fill_data data = {
1470 .perms = {
1471 .mode = S_IFREG | 0600,
1472 .uid = GLOBAL_ROOT_UID,
1473 .gid = GLOBAL_ROOT_GID,
1474 },
1475 .root_mode = S_IFDIR | 0500,
1476 .no_disconnect = false,
1477 };
1478 struct dentry *rv;
1479 int ret;
1480 void *ffs_dev;
1481 struct ffs_data *ffs;
1482
1483 ENTER();
1484
1485 ret = ffs_fs_parse_opts(&data, opts);
1486 if (unlikely(ret < 0))
1487 return ERR_PTR(ret);
1488
1489 ffs = ffs_data_new();
1490 if (unlikely(!ffs))
1491 return ERR_PTR(-ENOMEM);
1492 ffs->file_perms = data.perms;
1493 ffs->no_disconnect = data.no_disconnect;
1494
1495 ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1496 if (unlikely(!ffs->dev_name)) {
1497 ffs_data_put(ffs);
1498 return ERR_PTR(-ENOMEM);
1499 }
1500
1501 ffs_dev = ffs_acquire_dev(dev_name);
1502 if (IS_ERR(ffs_dev)) {
1503 ffs_data_put(ffs);
1504 return ERR_CAST(ffs_dev);
1505 }
1506 ffs->private_data = ffs_dev;
1507 data.ffs_data = ffs;
1508
1509 rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1510 if (IS_ERR(rv) && data.ffs_data) {
1511 ffs_release_dev(data.ffs_data);
1512 ffs_data_put(data.ffs_data);
1513 }
1514 return rv;
1515 }
1516
1517 static void
1518 ffs_fs_kill_sb(struct super_block *sb)
1519 {
1520 ENTER();
1521
1522 kill_litter_super(sb);
1523 if (sb->s_fs_info) {
1524 ffs_release_dev(sb->s_fs_info);
1525 ffs_data_closed(sb->s_fs_info);
1526 ffs_data_put(sb->s_fs_info);
1527 }
1528 }
1529
1530 static struct file_system_type ffs_fs_type = {
1531 .owner = THIS_MODULE,
1532 .name = "functionfs",
1533 .mount = ffs_fs_mount,
1534 .kill_sb = ffs_fs_kill_sb,
1535 };
1536 MODULE_ALIAS_FS("functionfs");
1537
1538
1539 /* Driver's main init/cleanup functions *************************************/
1540
1541 static int functionfs_init(void)
1542 {
1543 int ret;
1544
1545 ENTER();
1546
1547 ret = register_filesystem(&ffs_fs_type);
1548 if (likely(!ret))
1549 pr_info("file system registered\n");
1550 else
1551 pr_err("failed registering file system (%d)\n", ret);
1552
1553 return ret;
1554 }
1555
1556 static void functionfs_cleanup(void)
1557 {
1558 ENTER();
1559
1560 pr_info("unloading\n");
1561 unregister_filesystem(&ffs_fs_type);
1562 }
1563
1564
1565 /* ffs_data and ffs_function construction and destruction code **************/
1566
1567 static void ffs_data_clear(struct ffs_data *ffs);
1568 static void ffs_data_reset(struct ffs_data *ffs);
1569
1570 static void ffs_data_get(struct ffs_data *ffs)
1571 {
1572 ENTER();
1573
1574 atomic_inc(&ffs->ref);
1575 }
1576
1577 static void ffs_data_opened(struct ffs_data *ffs)
1578 {
1579 ENTER();
1580
1581 atomic_inc(&ffs->ref);
1582 if (atomic_add_return(1, &ffs->opened) == 1 &&
1583 ffs->state == FFS_DEACTIVATED) {
1584 ffs->state = FFS_CLOSING;
1585 ffs_data_reset(ffs);
1586 }
1587 }
1588
1589 static void ffs_data_put(struct ffs_data *ffs)
1590 {
1591 ENTER();
1592
1593 if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1594 pr_info("%s(): freeing\n", __func__);
1595 ffs_data_clear(ffs);
1596 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1597 waitqueue_active(&ffs->ep0req_completion.wait));
1598 kfree(ffs->dev_name);
1599 kfree(ffs);
1600 }
1601 }
1602
1603 static void ffs_data_closed(struct ffs_data *ffs)
1604 {
1605 ENTER();
1606
1607 if (atomic_dec_and_test(&ffs->opened)) {
1608 if (ffs->no_disconnect) {
1609 ffs->state = FFS_DEACTIVATED;
1610 if (ffs->epfiles) {
1611 ffs_epfiles_destroy(ffs->epfiles,
1612 ffs->eps_count);
1613 ffs->epfiles = NULL;
1614 }
1615 if (ffs->setup_state == FFS_SETUP_PENDING)
1616 __ffs_ep0_stall(ffs);
1617 } else {
1618 ffs->state = FFS_CLOSING;
1619 ffs_data_reset(ffs);
1620 }
1621 }
1622 if (atomic_read(&ffs->opened) < 0) {
1623 ffs->state = FFS_CLOSING;
1624 ffs_data_reset(ffs);
1625 }
1626
1627 ffs_data_put(ffs);
1628 }
1629
1630 static struct ffs_data *ffs_data_new(void)
1631 {
1632 struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1633 if (unlikely(!ffs))
1634 return NULL;
1635
1636 ENTER();
1637
1638 atomic_set(&ffs->ref, 1);
1639 atomic_set(&ffs->opened, 0);
1640 ffs->state = FFS_READ_DESCRIPTORS;
1641 mutex_init(&ffs->mutex);
1642 spin_lock_init(&ffs->eps_lock);
1643 init_waitqueue_head(&ffs->ev.waitq);
1644 init_completion(&ffs->ep0req_completion);
1645
1646 /* XXX REVISIT need to update it in some places, or do we? */
1647 ffs->ev.can_stall = 1;
1648
1649 return ffs;
1650 }
1651
1652 static void ffs_data_clear(struct ffs_data *ffs)
1653 {
1654 ENTER();
1655
1656 ffs_closed(ffs);
1657
1658 BUG_ON(ffs->gadget);
1659
1660 if (ffs->epfiles)
1661 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1662
1663 if (ffs->ffs_eventfd)
1664 eventfd_ctx_put(ffs->ffs_eventfd);
1665
1666 kfree(ffs->raw_descs_data);
1667 kfree(ffs->raw_strings);
1668 kfree(ffs->stringtabs);
1669 }
1670
1671 static void ffs_data_reset(struct ffs_data *ffs)
1672 {
1673 ENTER();
1674
1675 ffs_data_clear(ffs);
1676
1677 ffs->epfiles = NULL;
1678 ffs->raw_descs_data = NULL;
1679 ffs->raw_descs = NULL;
1680 ffs->raw_strings = NULL;
1681 ffs->stringtabs = NULL;
1682
1683 ffs->raw_descs_length = 0;
1684 ffs->fs_descs_count = 0;
1685 ffs->hs_descs_count = 0;
1686 ffs->ss_descs_count = 0;
1687
1688 ffs->strings_count = 0;
1689 ffs->interfaces_count = 0;
1690 ffs->eps_count = 0;
1691
1692 ffs->ev.count = 0;
1693
1694 ffs->state = FFS_READ_DESCRIPTORS;
1695 ffs->setup_state = FFS_NO_SETUP;
1696 ffs->flags = 0;
1697 }
1698
1699
1700 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1701 {
1702 struct usb_gadget_strings **lang;
1703 int first_id;
1704
1705 ENTER();
1706
1707 if (WARN_ON(ffs->state != FFS_ACTIVE
1708 || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1709 return -EBADFD;
1710
1711 first_id = usb_string_ids_n(cdev, ffs->strings_count);
1712 if (unlikely(first_id < 0))
1713 return first_id;
1714
1715 ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1716 if (unlikely(!ffs->ep0req))
1717 return -ENOMEM;
1718 ffs->ep0req->complete = ffs_ep0_complete;
1719 ffs->ep0req->context = ffs;
1720
1721 lang = ffs->stringtabs;
1722 if (lang) {
1723 for (; *lang; ++lang) {
1724 struct usb_string *str = (*lang)->strings;
1725 int id = first_id;
1726 for (; str->s; ++id, ++str)
1727 str->id = id;
1728 }
1729 }
1730
1731 ffs->gadget = cdev->gadget;
1732 ffs_data_get(ffs);
1733 return 0;
1734 }
1735
1736 static void functionfs_unbind(struct ffs_data *ffs)
1737 {
1738 ENTER();
1739
1740 if (!WARN_ON(!ffs->gadget)) {
1741 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1742 ffs->ep0req = NULL;
1743 ffs->gadget = NULL;
1744 clear_bit(FFS_FL_BOUND, &ffs->flags);
1745 ffs_data_put(ffs);
1746 }
1747 }
1748
1749 static int ffs_epfiles_create(struct ffs_data *ffs)
1750 {
1751 struct ffs_epfile *epfile, *epfiles;
1752 unsigned i, count;
1753
1754 ENTER();
1755
1756 count = ffs->eps_count;
1757 epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1758 if (!epfiles)
1759 return -ENOMEM;
1760
1761 epfile = epfiles;
1762 for (i = 1; i <= count; ++i, ++epfile) {
1763 epfile->ffs = ffs;
1764 mutex_init(&epfile->mutex);
1765 init_waitqueue_head(&epfile->wait);
1766 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1767 sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1768 else
1769 sprintf(epfile->name, "ep%u", i);
1770 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1771 epfile,
1772 &ffs_epfile_operations);
1773 if (unlikely(!epfile->dentry)) {
1774 ffs_epfiles_destroy(epfiles, i - 1);
1775 return -ENOMEM;
1776 }
1777 }
1778
1779 ffs->epfiles = epfiles;
1780 return 0;
1781 }
1782
1783 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1784 {
1785 struct ffs_epfile *epfile = epfiles;
1786
1787 ENTER();
1788
1789 for (; count; --count, ++epfile) {
1790 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1791 waitqueue_active(&epfile->wait));
1792 if (epfile->dentry) {
1793 d_delete(epfile->dentry);
1794 dput(epfile->dentry);
1795 epfile->dentry = NULL;
1796 }
1797 }
1798
1799 kfree(epfiles);
1800 }
1801
1802 static void ffs_func_eps_disable(struct ffs_function *func)
1803 {
1804 struct ffs_ep *ep = func->eps;
1805 struct ffs_epfile *epfile = func->ffs->epfiles;
1806 unsigned count = func->ffs->eps_count;
1807 unsigned long flags;
1808
1809 spin_lock_irqsave(&func->ffs->eps_lock, flags);
1810 while (count--) {
1811 /* pending requests get nuked */
1812 if (likely(ep->ep))
1813 usb_ep_disable(ep->ep);
1814 ++ep;
1815
1816 if (epfile) {
1817 epfile->ep = NULL;
1818 __ffs_epfile_read_buffer_free(epfile);
1819 ++epfile;
1820 }
1821 }
1822 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1823 }
1824
1825 static int ffs_func_eps_enable(struct ffs_function *func)
1826 {
1827 struct ffs_data *ffs = func->ffs;
1828 struct ffs_ep *ep = func->eps;
1829 struct ffs_epfile *epfile = ffs->epfiles;
1830 unsigned count = ffs->eps_count;
1831 unsigned long flags;
1832 int ret = 0;
1833
1834 spin_lock_irqsave(&func->ffs->eps_lock, flags);
1835 while(count--) {
1836 struct usb_endpoint_descriptor *ds;
1837 struct usb_ss_ep_comp_descriptor *comp_desc = NULL;
1838 int needs_comp_desc = false;
1839 int desc_idx;
1840
1841 if (ffs->gadget->speed == USB_SPEED_SUPER) {
1842 desc_idx = 2;
1843 needs_comp_desc = true;
1844 } else if (ffs->gadget->speed == USB_SPEED_HIGH)
1845 desc_idx = 1;
1846 else
1847 desc_idx = 0;
1848
1849 /* fall-back to lower speed if desc missing for current speed */
1850 do {
1851 ds = ep->descs[desc_idx];
1852 } while (!ds && --desc_idx >= 0);
1853
1854 if (!ds) {
1855 ret = -EINVAL;
1856 break;
1857 }
1858
1859 ep->ep->driver_data = ep;
1860 ep->ep->desc = ds;
1861
1862 comp_desc = (struct usb_ss_ep_comp_descriptor *)(ds +
1863 USB_DT_ENDPOINT_SIZE);
1864 ep->ep->maxburst = comp_desc->bMaxBurst + 1;
1865
1866 if (needs_comp_desc)
1867 ep->ep->comp_desc = comp_desc;
1868
1869 ret = usb_ep_enable(ep->ep);
1870 if (likely(!ret)) {
1871 epfile->ep = ep;
1872 epfile->in = usb_endpoint_dir_in(ds);
1873 epfile->isoc = usb_endpoint_xfer_isoc(ds);
1874 } else {
1875 break;
1876 }
1877
1878 wake_up(&epfile->wait);
1879
1880 ++ep;
1881 ++epfile;
1882 }
1883 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1884
1885 return ret;
1886 }
1887
1888
1889 /* Parsing and building descriptors and strings *****************************/
1890
1891 /*
1892 * This validates if data pointed by data is a valid USB descriptor as
1893 * well as record how many interfaces, endpoints and strings are
1894 * required by given configuration. Returns address after the
1895 * descriptor or NULL if data is invalid.
1896 */
1897
1898 enum ffs_entity_type {
1899 FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1900 };
1901
1902 enum ffs_os_desc_type {
1903 FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1904 };
1905
1906 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1907 u8 *valuep,
1908 struct usb_descriptor_header *desc,
1909 void *priv);
1910
1911 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1912 struct usb_os_desc_header *h, void *data,
1913 unsigned len, void *priv);
1914
1915 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1916 ffs_entity_callback entity,
1917 void *priv)
1918 {
1919 struct usb_descriptor_header *_ds = (void *)data;
1920 u8 length;
1921 int ret;
1922
1923 ENTER();
1924
1925 /* At least two bytes are required: length and type */
1926 if (len < 2) {
1927 pr_vdebug("descriptor too short\n");
1928 return -EINVAL;
1929 }
1930
1931 /* If we have at least as many bytes as the descriptor takes? */
1932 length = _ds->bLength;
1933 if (len < length) {
1934 pr_vdebug("descriptor longer then available data\n");
1935 return -EINVAL;
1936 }
1937
1938 #define __entity_check_INTERFACE(val) 1
1939 #define __entity_check_STRING(val) (val)
1940 #define __entity_check_ENDPOINT(val) ((val) & USB_ENDPOINT_NUMBER_MASK)
1941 #define __entity(type, val) do { \
1942 pr_vdebug("entity " #type "(%02x)\n", (val)); \
1943 if (unlikely(!__entity_check_ ##type(val))) { \
1944 pr_vdebug("invalid entity's value\n"); \
1945 return -EINVAL; \
1946 } \
1947 ret = entity(FFS_ ##type, &val, _ds, priv); \
1948 if (unlikely(ret < 0)) { \
1949 pr_debug("entity " #type "(%02x); ret = %d\n", \
1950 (val), ret); \
1951 return ret; \
1952 } \
1953 } while (0)
1954
1955 /* Parse descriptor depending on type. */
1956 switch (_ds->bDescriptorType) {
1957 case USB_DT_DEVICE:
1958 case USB_DT_CONFIG:
1959 case USB_DT_STRING:
1960 case USB_DT_DEVICE_QUALIFIER:
1961 /* function can't have any of those */
1962 pr_vdebug("descriptor reserved for gadget: %d\n",
1963 _ds->bDescriptorType);
1964 return -EINVAL;
1965
1966 case USB_DT_INTERFACE: {
1967 struct usb_interface_descriptor *ds = (void *)_ds;
1968 pr_vdebug("interface descriptor\n");
1969 if (length != sizeof *ds)
1970 goto inv_length;
1971
1972 __entity(INTERFACE, ds->bInterfaceNumber);
1973 if (ds->iInterface)
1974 __entity(STRING, ds->iInterface);
1975 }
1976 break;
1977
1978 case USB_DT_ENDPOINT: {
1979 struct usb_endpoint_descriptor *ds = (void *)_ds;
1980 pr_vdebug("endpoint descriptor\n");
1981 if (length != USB_DT_ENDPOINT_SIZE &&
1982 length != USB_DT_ENDPOINT_AUDIO_SIZE)
1983 goto inv_length;
1984 __entity(ENDPOINT, ds->bEndpointAddress);
1985 }
1986 break;
1987
1988 case HID_DT_HID:
1989 pr_vdebug("hid descriptor\n");
1990 if (length != sizeof(struct hid_descriptor))
1991 goto inv_length;
1992 break;
1993
1994 case USB_DT_OTG:
1995 if (length != sizeof(struct usb_otg_descriptor))
1996 goto inv_length;
1997 break;
1998
1999 case USB_DT_INTERFACE_ASSOCIATION: {
2000 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2001 pr_vdebug("interface association descriptor\n");
2002 if (length != sizeof *ds)
2003 goto inv_length;
2004 if (ds->iFunction)
2005 __entity(STRING, ds->iFunction);
2006 }
2007 break;
2008
2009 case USB_DT_SS_ENDPOINT_COMP:
2010 pr_vdebug("EP SS companion descriptor\n");
2011 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2012 goto inv_length;
2013 break;
2014
2015 case USB_DT_OTHER_SPEED_CONFIG:
2016 case USB_DT_INTERFACE_POWER:
2017 case USB_DT_DEBUG:
2018 case USB_DT_SECURITY:
2019 case USB_DT_CS_RADIO_CONTROL:
2020 /* TODO */
2021 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2022 return -EINVAL;
2023
2024 default:
2025 /* We should never be here */
2026 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2027 return -EINVAL;
2028
2029 inv_length:
2030 pr_vdebug("invalid length: %d (descriptor %d)\n",
2031 _ds->bLength, _ds->bDescriptorType);
2032 return -EINVAL;
2033 }
2034
2035 #undef __entity
2036 #undef __entity_check_DESCRIPTOR
2037 #undef __entity_check_INTERFACE
2038 #undef __entity_check_STRING
2039 #undef __entity_check_ENDPOINT
2040
2041 return length;
2042 }
2043
2044 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2045 ffs_entity_callback entity, void *priv)
2046 {
2047 const unsigned _len = len;
2048 unsigned long num = 0;
2049
2050 ENTER();
2051
2052 for (;;) {
2053 int ret;
2054
2055 if (num == count)
2056 data = NULL;
2057
2058 /* Record "descriptor" entity */
2059 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2060 if (unlikely(ret < 0)) {
2061 pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2062 num, ret);
2063 return ret;
2064 }
2065
2066 if (!data)
2067 return _len - len;
2068
2069 ret = ffs_do_single_desc(data, len, entity, priv);
2070 if (unlikely(ret < 0)) {
2071 pr_debug("%s returns %d\n", __func__, ret);
2072 return ret;
2073 }
2074
2075 len -= ret;
2076 data += ret;
2077 ++num;
2078 }
2079 }
2080
2081 static int __ffs_data_do_entity(enum ffs_entity_type type,
2082 u8 *valuep, struct usb_descriptor_header *desc,
2083 void *priv)
2084 {
2085 struct ffs_desc_helper *helper = priv;
2086 struct usb_endpoint_descriptor *d;
2087
2088 ENTER();
2089
2090 switch (type) {
2091 case FFS_DESCRIPTOR:
2092 break;
2093
2094 case FFS_INTERFACE:
2095 /*
2096 * Interfaces are indexed from zero so if we
2097 * encountered interface "n" then there are at least
2098 * "n+1" interfaces.
2099 */
2100 if (*valuep >= helper->interfaces_count)
2101 helper->interfaces_count = *valuep + 1;
2102 break;
2103
2104 case FFS_STRING:
2105 /*
2106 * Strings are indexed from 1 (0 is reserved
2107 * for languages list)
2108 */
2109 if (*valuep > helper->ffs->strings_count)
2110 helper->ffs->strings_count = *valuep;
2111 break;
2112
2113 case FFS_ENDPOINT:
2114 d = (void *)desc;
2115 helper->eps_count++;
2116 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2117 return -EINVAL;
2118 /* Check if descriptors for any speed were already parsed */
2119 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2120 helper->ffs->eps_addrmap[helper->eps_count] =
2121 d->bEndpointAddress;
2122 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2123 d->bEndpointAddress)
2124 return -EINVAL;
2125 break;
2126 }
2127
2128 return 0;
2129 }
2130
2131 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2132 struct usb_os_desc_header *desc)
2133 {
2134 u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2135 u16 w_index = le16_to_cpu(desc->wIndex);
2136
2137 if (bcd_version != 1) {
2138 pr_vdebug("unsupported os descriptors version: %d",
2139 bcd_version);
2140 return -EINVAL;
2141 }
2142 switch (w_index) {
2143 case 0x4:
2144 *next_type = FFS_OS_DESC_EXT_COMPAT;
2145 break;
2146 case 0x5:
2147 *next_type = FFS_OS_DESC_EXT_PROP;
2148 break;
2149 default:
2150 pr_vdebug("unsupported os descriptor type: %d", w_index);
2151 return -EINVAL;
2152 }
2153
2154 return sizeof(*desc);
2155 }
2156
2157 /*
2158 * Process all extended compatibility/extended property descriptors
2159 * of a feature descriptor
2160 */
2161 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2162 enum ffs_os_desc_type type,
2163 u16 feature_count,
2164 ffs_os_desc_callback entity,
2165 void *priv,
2166 struct usb_os_desc_header *h)
2167 {
2168 int ret;
2169 const unsigned _len = len;
2170
2171 ENTER();
2172
2173 /* loop over all ext compat/ext prop descriptors */
2174 while (feature_count--) {
2175 ret = entity(type, h, data, len, priv);
2176 if (unlikely(ret < 0)) {
2177 pr_debug("bad OS descriptor, type: %d\n", type);
2178 return ret;
2179 }
2180 data += ret;
2181 len -= ret;
2182 }
2183 return _len - len;
2184 }
2185
2186 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2187 static int __must_check ffs_do_os_descs(unsigned count,
2188 char *data, unsigned len,
2189 ffs_os_desc_callback entity, void *priv)
2190 {
2191 const unsigned _len = len;
2192 unsigned long num = 0;
2193
2194 ENTER();
2195
2196 for (num = 0; num < count; ++num) {
2197 int ret;
2198 enum ffs_os_desc_type type;
2199 u16 feature_count;
2200 struct usb_os_desc_header *desc = (void *)data;
2201
2202 if (len < sizeof(*desc))
2203 return -EINVAL;
2204
2205 /*
2206 * Record "descriptor" entity.
2207 * Process dwLength, bcdVersion, wIndex, get b/wCount.
2208 * Move the data pointer to the beginning of extended
2209 * compatibilities proper or extended properties proper
2210 * portions of the data
2211 */
2212 if (le32_to_cpu(desc->dwLength) > len)
2213 return -EINVAL;
2214
2215 ret = __ffs_do_os_desc_header(&type, desc);
2216 if (unlikely(ret < 0)) {
2217 pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2218 num, ret);
2219 return ret;
2220 }
2221 /*
2222 * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2223 */
2224 feature_count = le16_to_cpu(desc->wCount);
2225 if (type == FFS_OS_DESC_EXT_COMPAT &&
2226 (feature_count > 255 || desc->Reserved))
2227 return -EINVAL;
2228 len -= ret;
2229 data += ret;
2230
2231 /*
2232 * Process all function/property descriptors
2233 * of this Feature Descriptor
2234 */
2235 ret = ffs_do_single_os_desc(data, len, type,
2236 feature_count, entity, priv, desc);
2237 if (unlikely(ret < 0)) {
2238 pr_debug("%s returns %d\n", __func__, ret);
2239 return ret;
2240 }
2241
2242 len -= ret;
2243 data += ret;
2244 }
2245 return _len - len;
2246 }
2247
2248 /**
2249 * Validate contents of the buffer from userspace related to OS descriptors.
2250 */
2251 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2252 struct usb_os_desc_header *h, void *data,
2253 unsigned len, void *priv)
2254 {
2255 struct ffs_data *ffs = priv;
2256 u8 length;
2257
2258 ENTER();
2259
2260 switch (type) {
2261 case FFS_OS_DESC_EXT_COMPAT: {
2262 struct usb_ext_compat_desc *d = data;
2263 int i;
2264
2265 if (len < sizeof(*d) ||
2266 d->bFirstInterfaceNumber >= ffs->interfaces_count ||
2267 !d->Reserved1)
2268 return -EINVAL;
2269 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2270 if (d->Reserved2[i])
2271 return -EINVAL;
2272
2273 length = sizeof(struct usb_ext_compat_desc);
2274 }
2275 break;
2276 case FFS_OS_DESC_EXT_PROP: {
2277 struct usb_ext_prop_desc *d = data;
2278 u32 type, pdl;
2279 u16 pnl;
2280
2281 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2282 return -EINVAL;
2283 length = le32_to_cpu(d->dwSize);
2284 if (len < length)
2285 return -EINVAL;
2286 type = le32_to_cpu(d->dwPropertyDataType);
2287 if (type < USB_EXT_PROP_UNICODE ||
2288 type > USB_EXT_PROP_UNICODE_MULTI) {
2289 pr_vdebug("unsupported os descriptor property type: %d",
2290 type);
2291 return -EINVAL;
2292 }
2293 pnl = le16_to_cpu(d->wPropertyNameLength);
2294 if (length < 14 + pnl) {
2295 pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2296 length, pnl, type);
2297 return -EINVAL;
2298 }
2299 pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
2300 if (length != 14 + pnl + pdl) {
2301 pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2302 length, pnl, pdl, type);
2303 return -EINVAL;
2304 }
2305 ++ffs->ms_os_descs_ext_prop_count;
2306 /* property name reported to the host as "WCHAR"s */
2307 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2308 ffs->ms_os_descs_ext_prop_data_len += pdl;
2309 }
2310 break;
2311 default:
2312 pr_vdebug("unknown descriptor: %d\n", type);
2313 return -EINVAL;
2314 }
2315 return length;
2316 }
2317
2318 static int __ffs_data_got_descs(struct ffs_data *ffs,
2319 char *const _data, size_t len)
2320 {
2321 char *data = _data, *raw_descs;
2322 unsigned os_descs_count = 0, counts[3], flags;
2323 int ret = -EINVAL, i;
2324 struct ffs_desc_helper helper;
2325
2326 ENTER();
2327
2328 if (get_unaligned_le32(data + 4) != len)
2329 goto error;
2330
2331 switch (get_unaligned_le32(data)) {
2332 case FUNCTIONFS_DESCRIPTORS_MAGIC:
2333 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2334 data += 8;
2335 len -= 8;
2336 break;
2337 case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2338 flags = get_unaligned_le32(data + 8);
2339 ffs->user_flags = flags;
2340 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2341 FUNCTIONFS_HAS_HS_DESC |
2342 FUNCTIONFS_HAS_SS_DESC |
2343 FUNCTIONFS_HAS_MS_OS_DESC |
2344 FUNCTIONFS_VIRTUAL_ADDR |
2345 FUNCTIONFS_EVENTFD |
2346 FUNCTIONFS_ALL_CTRL_RECIP |
2347 FUNCTIONFS_CONFIG0_SETUP)) {
2348 ret = -ENOSYS;
2349 goto error;
2350 }
2351 data += 12;
2352 len -= 12;
2353 break;
2354 default:
2355 goto error;
2356 }
2357
2358 if (flags & FUNCTIONFS_EVENTFD) {
2359 if (len < 4)
2360 goto error;
2361 ffs->ffs_eventfd =
2362 eventfd_ctx_fdget((int)get_unaligned_le32(data));
2363 if (IS_ERR(ffs->ffs_eventfd)) {
2364 ret = PTR_ERR(ffs->ffs_eventfd);
2365 ffs->ffs_eventfd = NULL;
2366 goto error;
2367 }
2368 data += 4;
2369 len -= 4;
2370 }
2371
2372 /* Read fs_count, hs_count and ss_count (if present) */
2373 for (i = 0; i < 3; ++i) {
2374 if (!(flags & (1 << i))) {
2375 counts[i] = 0;
2376 } else if (len < 4) {
2377 goto error;
2378 } else {
2379 counts[i] = get_unaligned_le32(data);
2380 data += 4;
2381 len -= 4;
2382 }
2383 }
2384 if (flags & (1 << i)) {
2385 if (len < 4) {
2386 goto error;
2387 }
2388 os_descs_count = get_unaligned_le32(data);
2389 data += 4;
2390 len -= 4;
2391 };
2392
2393 /* Read descriptors */
2394 raw_descs = data;
2395 helper.ffs = ffs;
2396 for (i = 0; i < 3; ++i) {
2397 if (!counts[i])
2398 continue;
2399 helper.interfaces_count = 0;
2400 helper.eps_count = 0;
2401 ret = ffs_do_descs(counts[i], data, len,
2402 __ffs_data_do_entity, &helper);
2403 if (ret < 0)
2404 goto error;
2405 if (!ffs->eps_count && !ffs->interfaces_count) {
2406 ffs->eps_count = helper.eps_count;
2407 ffs->interfaces_count = helper.interfaces_count;
2408 } else {
2409 if (ffs->eps_count != helper.eps_count) {
2410 ret = -EINVAL;
2411 goto error;
2412 }
2413 if (ffs->interfaces_count != helper.interfaces_count) {
2414 ret = -EINVAL;
2415 goto error;
2416 }
2417 }
2418 data += ret;
2419 len -= ret;
2420 }
2421 if (os_descs_count) {
2422 ret = ffs_do_os_descs(os_descs_count, data, len,
2423 __ffs_data_do_os_desc, ffs);
2424 if (ret < 0)
2425 goto error;
2426 data += ret;
2427 len -= ret;
2428 }
2429
2430 if (raw_descs == data || len) {
2431 ret = -EINVAL;
2432 goto error;
2433 }
2434
2435 ffs->raw_descs_data = _data;
2436 ffs->raw_descs = raw_descs;
2437 ffs->raw_descs_length = data - raw_descs;
2438 ffs->fs_descs_count = counts[0];
2439 ffs->hs_descs_count = counts[1];
2440 ffs->ss_descs_count = counts[2];
2441 ffs->ms_os_descs_count = os_descs_count;
2442
2443 return 0;
2444
2445 error:
2446 kfree(_data);
2447 return ret;
2448 }
2449
2450 static int __ffs_data_got_strings(struct ffs_data *ffs,
2451 char *const _data, size_t len)
2452 {
2453 u32 str_count, needed_count, lang_count;
2454 struct usb_gadget_strings **stringtabs, *t;
2455 const char *data = _data;
2456 struct usb_string *s;
2457
2458 ENTER();
2459
2460 if (unlikely(len < 16 ||
2461 get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2462 get_unaligned_le32(data + 4) != len))
2463 goto error;
2464 str_count = get_unaligned_le32(data + 8);
2465 lang_count = get_unaligned_le32(data + 12);
2466
2467 /* if one is zero the other must be zero */
2468 if (unlikely(!str_count != !lang_count))
2469 goto error;
2470
2471 /* Do we have at least as many strings as descriptors need? */
2472 needed_count = ffs->strings_count;
2473 if (unlikely(str_count < needed_count))
2474 goto error;
2475
2476 /*
2477 * If we don't need any strings just return and free all
2478 * memory.
2479 */
2480 if (!needed_count) {
2481 kfree(_data);
2482 return 0;
2483 }
2484
2485 /* Allocate everything in one chunk so there's less maintenance. */
2486 {
2487 unsigned i = 0;
2488 vla_group(d);
2489 vla_item(d, struct usb_gadget_strings *, stringtabs,
2490 lang_count + 1);
2491 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2492 vla_item(d, struct usb_string, strings,
2493 lang_count*(needed_count+1));
2494
2495 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2496
2497 if (unlikely(!vlabuf)) {
2498 kfree(_data);
2499 return -ENOMEM;
2500 }
2501
2502 /* Initialize the VLA pointers */
2503 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2504 t = vla_ptr(vlabuf, d, stringtab);
2505 i = lang_count;
2506 do {
2507 *stringtabs++ = t++;
2508 } while (--i);
2509 *stringtabs = NULL;
2510
2511 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2512 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2513 t = vla_ptr(vlabuf, d, stringtab);
2514 s = vla_ptr(vlabuf, d, strings);
2515 }
2516
2517 /* For each language */
2518 data += 16;
2519 len -= 16;
2520
2521 do { /* lang_count > 0 so we can use do-while */
2522 unsigned needed = needed_count;
2523
2524 if (unlikely(len < 3))
2525 goto error_free;
2526 t->language = get_unaligned_le16(data);
2527 t->strings = s;
2528 ++t;
2529
2530 data += 2;
2531 len -= 2;
2532
2533 /* For each string */
2534 do { /* str_count > 0 so we can use do-while */
2535 size_t length = strnlen(data, len);
2536
2537 if (unlikely(length == len))
2538 goto error_free;
2539
2540 /*
2541 * User may provide more strings then we need,
2542 * if that's the case we simply ignore the
2543 * rest
2544 */
2545 if (likely(needed)) {
2546 /*
2547 * s->id will be set while adding
2548 * function to configuration so for
2549 * now just leave garbage here.
2550 */
2551 s->s = data;
2552 --needed;
2553 ++s;
2554 }
2555
2556 data += length + 1;
2557 len -= length + 1;
2558 } while (--str_count);
2559
2560 s->id = 0; /* terminator */
2561 s->s = NULL;
2562 ++s;
2563
2564 } while (--lang_count);
2565
2566 /* Some garbage left? */
2567 if (unlikely(len))
2568 goto error_free;
2569
2570 /* Done! */
2571 ffs->stringtabs = stringtabs;
2572 ffs->raw_strings = _data;
2573
2574 return 0;
2575
2576 error_free:
2577 kfree(stringtabs);
2578 error:
2579 kfree(_data);
2580 return -EINVAL;
2581 }
2582
2583
2584 /* Events handling and management *******************************************/
2585
2586 static void __ffs_event_add(struct ffs_data *ffs,
2587 enum usb_functionfs_event_type type)
2588 {
2589 enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2590 int neg = 0;
2591
2592 /*
2593 * Abort any unhandled setup
2594 *
2595 * We do not need to worry about some cmpxchg() changing value
2596 * of ffs->setup_state without holding the lock because when
2597 * state is FFS_SETUP_PENDING cmpxchg() in several places in
2598 * the source does nothing.
2599 */
2600 if (ffs->setup_state == FFS_SETUP_PENDING)
2601 ffs->setup_state = FFS_SETUP_CANCELLED;
2602
2603 /*
2604 * Logic of this function guarantees that there are at most four pending
2605 * evens on ffs->ev.types queue. This is important because the queue
2606 * has space for four elements only and __ffs_ep0_read_events function
2607 * depends on that limit as well. If more event types are added, those
2608 * limits have to be revisited or guaranteed to still hold.
2609 */
2610 switch (type) {
2611 case FUNCTIONFS_RESUME:
2612 rem_type2 = FUNCTIONFS_SUSPEND;
2613 /* FALL THROUGH */
2614 case FUNCTIONFS_SUSPEND:
2615 case FUNCTIONFS_SETUP:
2616 rem_type1 = type;
2617 /* Discard all similar events */
2618 break;
2619
2620 case FUNCTIONFS_BIND:
2621 case FUNCTIONFS_UNBIND:
2622 case FUNCTIONFS_DISABLE:
2623 case FUNCTIONFS_ENABLE:
2624 /* Discard everything other then power management. */
2625 rem_type1 = FUNCTIONFS_SUSPEND;
2626 rem_type2 = FUNCTIONFS_RESUME;
2627 neg = 1;
2628 break;
2629
2630 default:
2631 WARN(1, "%d: unknown event, this should not happen\n", type);
2632 return;
2633 }
2634
2635 {
2636 u8 *ev = ffs->ev.types, *out = ev;
2637 unsigned n = ffs->ev.count;
2638 for (; n; --n, ++ev)
2639 if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2640 *out++ = *ev;
2641 else
2642 pr_vdebug("purging event %d\n", *ev);
2643 ffs->ev.count = out - ffs->ev.types;
2644 }
2645
2646 pr_vdebug("adding event %d\n", type);
2647 ffs->ev.types[ffs->ev.count++] = type;
2648 wake_up_locked(&ffs->ev.waitq);
2649 if (ffs->ffs_eventfd)
2650 eventfd_signal(ffs->ffs_eventfd, 1);
2651 }
2652
2653 static void ffs_event_add(struct ffs_data *ffs,
2654 enum usb_functionfs_event_type type)
2655 {
2656 unsigned long flags;
2657 spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2658 __ffs_event_add(ffs, type);
2659 spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2660 }
2661
2662 /* Bind/unbind USB function hooks *******************************************/
2663
2664 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2665 {
2666 int i;
2667
2668 for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2669 if (ffs->eps_addrmap[i] == endpoint_address)
2670 return i;
2671 return -ENOENT;
2672 }
2673
2674 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2675 struct usb_descriptor_header *desc,
2676 void *priv)
2677 {
2678 struct usb_endpoint_descriptor *ds = (void *)desc;
2679 struct ffs_function *func = priv;
2680 struct ffs_ep *ffs_ep;
2681 unsigned ep_desc_id;
2682 int idx;
2683 static const char *speed_names[] = { "full", "high", "super" };
2684
2685 if (type != FFS_DESCRIPTOR)
2686 return 0;
2687
2688 /*
2689 * If ss_descriptors is not NULL, we are reading super speed
2690 * descriptors; if hs_descriptors is not NULL, we are reading high
2691 * speed descriptors; otherwise, we are reading full speed
2692 * descriptors.
2693 */
2694 if (func->function.ss_descriptors) {
2695 ep_desc_id = 2;
2696 func->function.ss_descriptors[(long)valuep] = desc;
2697 } else if (func->function.hs_descriptors) {
2698 ep_desc_id = 1;
2699 func->function.hs_descriptors[(long)valuep] = desc;
2700 } else {
2701 ep_desc_id = 0;
2702 func->function.fs_descriptors[(long)valuep] = desc;
2703 }
2704
2705 if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2706 return 0;
2707
2708 idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2709 if (idx < 0)
2710 return idx;
2711
2712 ffs_ep = func->eps + idx;
2713
2714 if (unlikely(ffs_ep->descs[ep_desc_id])) {
2715 pr_err("two %sspeed descriptors for EP %d\n",
2716 speed_names[ep_desc_id],
2717 ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2718 return -EINVAL;
2719 }
2720 ffs_ep->descs[ep_desc_id] = ds;
2721
2722 ffs_dump_mem(": Original ep desc", ds, ds->bLength);
2723 if (ffs_ep->ep) {
2724 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2725 if (!ds->wMaxPacketSize)
2726 ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2727 } else {
2728 struct usb_request *req;
2729 struct usb_ep *ep;
2730 u8 bEndpointAddress;
2731
2732 /*
2733 * We back up bEndpointAddress because autoconfig overwrites
2734 * it with physical endpoint address.
2735 */
2736 bEndpointAddress = ds->bEndpointAddress;
2737 pr_vdebug("autoconfig\n");
2738 ep = usb_ep_autoconfig(func->gadget, ds);
2739 if (unlikely(!ep))
2740 return -ENOTSUPP;
2741 ep->driver_data = func->eps + idx;
2742
2743 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2744 if (unlikely(!req))
2745 return -ENOMEM;
2746
2747 ffs_ep->ep = ep;
2748 ffs_ep->req = req;
2749 func->eps_revmap[ds->bEndpointAddress &
2750 USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2751 /*
2752 * If we use virtual address mapping, we restore
2753 * original bEndpointAddress value.
2754 */
2755 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2756 ds->bEndpointAddress = bEndpointAddress;
2757 }
2758 ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2759
2760 return 0;
2761 }
2762
2763 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2764 struct usb_descriptor_header *desc,
2765 void *priv)
2766 {
2767 struct ffs_function *func = priv;
2768 unsigned idx;
2769 u8 newValue;
2770
2771 switch (type) {
2772 default:
2773 case FFS_DESCRIPTOR:
2774 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2775 return 0;
2776
2777 case FFS_INTERFACE:
2778 idx = *valuep;
2779 if (func->interfaces_nums[idx] < 0) {
2780 int id = usb_interface_id(func->conf, &func->function);
2781 if (unlikely(id < 0))
2782 return id;
2783 func->interfaces_nums[idx] = id;
2784 }
2785 newValue = func->interfaces_nums[idx];
2786 break;
2787
2788 case FFS_STRING:
2789 /* String' IDs are allocated when fsf_data is bound to cdev */
2790 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2791 break;
2792
2793 case FFS_ENDPOINT:
2794 /*
2795 * USB_DT_ENDPOINT are handled in
2796 * __ffs_func_bind_do_descs().
2797 */
2798 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2799 return 0;
2800
2801 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2802 if (unlikely(!func->eps[idx].ep))
2803 return -EINVAL;
2804
2805 {
2806 struct usb_endpoint_descriptor **descs;
2807 descs = func->eps[idx].descs;
2808 newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2809 }
2810 break;
2811 }
2812
2813 pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2814 *valuep = newValue;
2815 return 0;
2816 }
2817
2818 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2819 struct usb_os_desc_header *h, void *data,
2820 unsigned len, void *priv)
2821 {
2822 struct ffs_function *func = priv;
2823 u8 length = 0;
2824
2825 switch (type) {
2826 case FFS_OS_DESC_EXT_COMPAT: {
2827 struct usb_ext_compat_desc *desc = data;
2828 struct usb_os_desc_table *t;
2829
2830 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2831 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2832 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2833 ARRAY_SIZE(desc->CompatibleID) +
2834 ARRAY_SIZE(desc->SubCompatibleID));
2835 length = sizeof(*desc);
2836 }
2837 break;
2838 case FFS_OS_DESC_EXT_PROP: {
2839 struct usb_ext_prop_desc *desc = data;
2840 struct usb_os_desc_table *t;
2841 struct usb_os_desc_ext_prop *ext_prop;
2842 char *ext_prop_name;
2843 char *ext_prop_data;
2844
2845 t = &func->function.os_desc_table[h->interface];
2846 t->if_id = func->interfaces_nums[h->interface];
2847
2848 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2849 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2850
2851 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2852 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2853 ext_prop->data_len = le32_to_cpu(*(u32 *)
2854 usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2855 length = ext_prop->name_len + ext_prop->data_len + 14;
2856
2857 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2858 func->ffs->ms_os_descs_ext_prop_name_avail +=
2859 ext_prop->name_len;
2860
2861 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2862 func->ffs->ms_os_descs_ext_prop_data_avail +=
2863 ext_prop->data_len;
2864 memcpy(ext_prop_data,
2865 usb_ext_prop_data_ptr(data, ext_prop->name_len),
2866 ext_prop->data_len);
2867 /* unicode data reported to the host as "WCHAR"s */
2868 switch (ext_prop->type) {
2869 case USB_EXT_PROP_UNICODE:
2870 case USB_EXT_PROP_UNICODE_ENV:
2871 case USB_EXT_PROP_UNICODE_LINK:
2872 case USB_EXT_PROP_UNICODE_MULTI:
2873 ext_prop->data_len *= 2;
2874 break;
2875 }
2876 ext_prop->data = ext_prop_data;
2877
2878 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2879 ext_prop->name_len);
2880 /* property name reported to the host as "WCHAR"s */
2881 ext_prop->name_len *= 2;
2882 ext_prop->name = ext_prop_name;
2883
2884 t->os_desc->ext_prop_len +=
2885 ext_prop->name_len + ext_prop->data_len + 14;
2886 ++t->os_desc->ext_prop_count;
2887 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2888 }
2889 break;
2890 default:
2891 pr_vdebug("unknown descriptor: %d\n", type);
2892 }
2893
2894 return length;
2895 }
2896
2897 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2898 struct usb_configuration *c)
2899 {
2900 struct ffs_function *func = ffs_func_from_usb(f);
2901 struct f_fs_opts *ffs_opts =
2902 container_of(f->fi, struct f_fs_opts, func_inst);
2903 int ret;
2904
2905 ENTER();
2906
2907 /*
2908 * Legacy gadget triggers binding in functionfs_ready_callback,
2909 * which already uses locking; taking the same lock here would
2910 * cause a deadlock.
2911 *
2912 * Configfs-enabled gadgets however do need ffs_dev_lock.
2913 */
2914 if (!ffs_opts->no_configfs)
2915 ffs_dev_lock();
2916 ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2917 func->ffs = ffs_opts->dev->ffs_data;
2918 if (!ffs_opts->no_configfs)
2919 ffs_dev_unlock();
2920 if (ret)
2921 return ERR_PTR(ret);
2922
2923 func->conf = c;
2924 func->gadget = c->cdev->gadget;
2925
2926 /*
2927 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2928 * configurations are bound in sequence with list_for_each_entry,
2929 * in each configuration its functions are bound in sequence
2930 * with list_for_each_entry, so we assume no race condition
2931 * with regard to ffs_opts->bound access
2932 */
2933 if (!ffs_opts->refcnt) {
2934 ret = functionfs_bind(func->ffs, c->cdev);
2935 if (ret)
2936 return ERR_PTR(ret);
2937 }
2938 ffs_opts->refcnt++;
2939 func->function.strings = func->ffs->stringtabs;
2940
2941 return ffs_opts;
2942 }
2943
2944 static int _ffs_func_bind(struct usb_configuration *c,
2945 struct usb_function *f)
2946 {
2947 struct ffs_function *func = ffs_func_from_usb(f);
2948 struct ffs_data *ffs = func->ffs;
2949
2950 const int full = !!func->ffs->fs_descs_count;
2951 const int high = gadget_is_dualspeed(func->gadget) &&
2952 func->ffs->hs_descs_count;
2953 const int super = gadget_is_superspeed(func->gadget) &&
2954 func->ffs->ss_descs_count;
2955
2956 int fs_len, hs_len, ss_len, ret, i;
2957 struct ffs_ep *eps_ptr;
2958
2959 /* Make it a single chunk, less management later on */
2960 vla_group(d);
2961 vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2962 vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2963 full ? ffs->fs_descs_count + 1 : 0);
2964 vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2965 high ? ffs->hs_descs_count + 1 : 0);
2966 vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2967 super ? ffs->ss_descs_count + 1 : 0);
2968 vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2969 vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2970 c->cdev->use_os_string ? ffs->interfaces_count : 0);
2971 vla_item_with_sz(d, char[16], ext_compat,
2972 c->cdev->use_os_string ? ffs->interfaces_count : 0);
2973 vla_item_with_sz(d, struct usb_os_desc, os_desc,
2974 c->cdev->use_os_string ? ffs->interfaces_count : 0);
2975 vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
2976 ffs->ms_os_descs_ext_prop_count);
2977 vla_item_with_sz(d, char, ext_prop_name,
2978 ffs->ms_os_descs_ext_prop_name_len);
2979 vla_item_with_sz(d, char, ext_prop_data,
2980 ffs->ms_os_descs_ext_prop_data_len);
2981 vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2982 char *vlabuf;
2983
2984 ENTER();
2985
2986 /* Has descriptors only for speeds gadget does not support */
2987 if (unlikely(!(full | high | super)))
2988 return -ENOTSUPP;
2989
2990 /* Allocate a single chunk, less management later on */
2991 vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
2992 if (unlikely(!vlabuf))
2993 return -ENOMEM;
2994
2995 ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
2996 ffs->ms_os_descs_ext_prop_name_avail =
2997 vla_ptr(vlabuf, d, ext_prop_name);
2998 ffs->ms_os_descs_ext_prop_data_avail =
2999 vla_ptr(vlabuf, d, ext_prop_data);
3000
3001 /* Copy descriptors */
3002 memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3003 ffs->raw_descs_length);
3004
3005 memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3006 eps_ptr = vla_ptr(vlabuf, d, eps);
3007 for (i = 0; i < ffs->eps_count; i++)
3008 eps_ptr[i].num = -1;
3009
3010 /* Save pointers
3011 * d_eps == vlabuf, func->eps used to kfree vlabuf later
3012 */
3013 func->eps = vla_ptr(vlabuf, d, eps);
3014 func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3015
3016 /*
3017 * Go through all the endpoint descriptors and allocate
3018 * endpoints first, so that later we can rewrite the endpoint
3019 * numbers without worrying that it may be described later on.
3020 */
3021 if (likely(full)) {
3022 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3023 fs_len = ffs_do_descs(ffs->fs_descs_count,
3024 vla_ptr(vlabuf, d, raw_descs),
3025 d_raw_descs__sz,
3026 __ffs_func_bind_do_descs, func);
3027 if (unlikely(fs_len < 0)) {
3028 ret = fs_len;
3029 goto error;
3030 }
3031 } else {
3032 fs_len = 0;
3033 }
3034
3035 if (likely(high)) {
3036 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3037 hs_len = ffs_do_descs(ffs->hs_descs_count,
3038 vla_ptr(vlabuf, d, raw_descs) + fs_len,
3039 d_raw_descs__sz - fs_len,
3040 __ffs_func_bind_do_descs, func);
3041 if (unlikely(hs_len < 0)) {
3042 ret = hs_len;
3043 goto error;
3044 }
3045 } else {
3046 hs_len = 0;
3047 }
3048
3049 if (likely(super)) {
3050 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3051 ss_len = ffs_do_descs(ffs->ss_descs_count,
3052 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3053 d_raw_descs__sz - fs_len - hs_len,
3054 __ffs_func_bind_do_descs, func);
3055 if (unlikely(ss_len < 0)) {
3056 ret = ss_len;
3057 goto error;
3058 }
3059 } else {
3060 ss_len = 0;
3061 }
3062
3063 /*
3064 * Now handle interface numbers allocation and interface and
3065 * endpoint numbers rewriting. We can do that in one go
3066 * now.
3067 */
3068 ret = ffs_do_descs(ffs->fs_descs_count +
3069 (high ? ffs->hs_descs_count : 0) +
3070 (super ? ffs->ss_descs_count : 0),
3071 vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3072 __ffs_func_bind_do_nums, func);
3073 if (unlikely(ret < 0))
3074 goto error;
3075
3076 func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3077 if (c->cdev->use_os_string) {
3078 for (i = 0; i < ffs->interfaces_count; ++i) {
3079 struct usb_os_desc *desc;
3080
3081 desc = func->function.os_desc_table[i].os_desc =
3082 vla_ptr(vlabuf, d, os_desc) +
3083 i * sizeof(struct usb_os_desc);
3084 desc->ext_compat_id =
3085 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3086 INIT_LIST_HEAD(&desc->ext_prop);
3087 }
3088 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3089 vla_ptr(vlabuf, d, raw_descs) +
3090 fs_len + hs_len + ss_len,
3091 d_raw_descs__sz - fs_len - hs_len -
3092 ss_len,
3093 __ffs_func_bind_do_os_desc, func);
3094 if (unlikely(ret < 0))
3095 goto error;
3096 }
3097 func->function.os_desc_n =
3098 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3099
3100 /* And we're done */
3101 ffs_event_add(ffs, FUNCTIONFS_BIND);
3102 return 0;
3103
3104 error:
3105 /* XXX Do we need to release all claimed endpoints here? */
3106 return ret;
3107 }
3108
3109 static int ffs_func_bind(struct usb_configuration *c,
3110 struct usb_function *f)
3111 {
3112 struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3113 struct ffs_function *func = ffs_func_from_usb(f);
3114 int ret;
3115
3116 if (IS_ERR(ffs_opts))
3117 return PTR_ERR(ffs_opts);
3118
3119 ret = _ffs_func_bind(c, f);
3120 if (ret && !--ffs_opts->refcnt)
3121 functionfs_unbind(func->ffs);
3122
3123 return ret;
3124 }
3125
3126
3127 /* Other USB function hooks *************************************************/
3128
3129 static void ffs_reset_work(struct work_struct *work)
3130 {
3131 struct ffs_data *ffs = container_of(work,
3132 struct ffs_data, reset_work);
3133 ffs_data_reset(ffs);
3134 }
3135
3136 static int ffs_func_set_alt(struct usb_function *f,
3137 unsigned interface, unsigned alt)
3138 {
3139 struct ffs_function *func = ffs_func_from_usb(f);
3140 struct ffs_data *ffs = func->ffs;
3141 int ret = 0, intf;
3142
3143 if (alt != (unsigned)-1) {
3144 intf = ffs_func_revmap_intf(func, interface);
3145 if (unlikely(intf < 0))
3146 return intf;
3147 }
3148
3149 if (ffs->func)
3150 ffs_func_eps_disable(ffs->func);
3151
3152 if (ffs->state == FFS_DEACTIVATED) {
3153 ffs->state = FFS_CLOSING;
3154 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3155 schedule_work(&ffs->reset_work);
3156 return -ENODEV;
3157 }
3158
3159 if (ffs->state != FFS_ACTIVE)
3160 return -ENODEV;
3161
3162 if (alt == (unsigned)-1) {
3163 ffs->func = NULL;
3164 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3165 return 0;
3166 }
3167
3168 ffs->func = func;
3169 ret = ffs_func_eps_enable(func);
3170 if (likely(ret >= 0))
3171 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3172 return ret;
3173 }
3174
3175 static void ffs_func_disable(struct usb_function *f)
3176 {
3177 ffs_func_set_alt(f, 0, (unsigned)-1);
3178 }
3179
3180 static int ffs_func_setup(struct usb_function *f,
3181 const struct usb_ctrlrequest *creq)
3182 {
3183 struct ffs_function *func = ffs_func_from_usb(f);
3184 struct ffs_data *ffs = func->ffs;
3185 unsigned long flags;
3186 int ret;
3187
3188 ENTER();
3189
3190 pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3191 pr_vdebug("creq->bRequest = %02x\n", creq->bRequest);
3192 pr_vdebug("creq->wValue = %04x\n", le16_to_cpu(creq->wValue));
3193 pr_vdebug("creq->wIndex = %04x\n", le16_to_cpu(creq->wIndex));
3194 pr_vdebug("creq->wLength = %04x\n", le16_to_cpu(creq->wLength));
3195
3196 /*
3197 * Most requests directed to interface go through here
3198 * (notable exceptions are set/get interface) so we need to
3199 * handle them. All other either handled by composite or
3200 * passed to usb_configuration->setup() (if one is set). No
3201 * matter, we will handle requests directed to endpoint here
3202 * as well (as it's straightforward). Other request recipient
3203 * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3204 * is being used.
3205 */
3206 if (ffs->state != FFS_ACTIVE)
3207 return -ENODEV;
3208
3209 switch (creq->bRequestType & USB_RECIP_MASK) {
3210 case USB_RECIP_INTERFACE:
3211 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3212 if (unlikely(ret < 0))
3213 return ret;
3214 break;
3215
3216 case USB_RECIP_ENDPOINT:
3217 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3218 if (unlikely(ret < 0))
3219 return ret;
3220 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3221 ret = func->ffs->eps_addrmap[ret];
3222 break;
3223
3224 default:
3225 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3226 ret = le16_to_cpu(creq->wIndex);
3227 else
3228 return -EOPNOTSUPP;
3229 }
3230
3231 spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3232 ffs->ev.setup = *creq;
3233 ffs->ev.setup.wIndex = cpu_to_le16(ret);
3234 __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3235 spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3236
3237 return 0;
3238 }
3239
3240 static bool ffs_func_req_match(struct usb_function *f,
3241 const struct usb_ctrlrequest *creq,
3242 bool config0)
3243 {
3244 struct ffs_function *func = ffs_func_from_usb(f);
3245
3246 if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3247 return false;
3248
3249 switch (creq->bRequestType & USB_RECIP_MASK) {
3250 case USB_RECIP_INTERFACE:
3251 return (ffs_func_revmap_intf(func,
3252 le16_to_cpu(creq->wIndex)) >= 0);
3253 case USB_RECIP_ENDPOINT:
3254 return (ffs_func_revmap_ep(func,
3255 le16_to_cpu(creq->wIndex)) >= 0);
3256 default:
3257 return (bool) (func->ffs->user_flags &
3258 FUNCTIONFS_ALL_CTRL_RECIP);
3259 }
3260 }
3261
3262 static void ffs_func_suspend(struct usb_function *f)
3263 {
3264 ENTER();
3265 ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3266 }
3267
3268 static void ffs_func_resume(struct usb_function *f)
3269 {
3270 ENTER();
3271 ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3272 }
3273
3274
3275 /* Endpoint and interface numbers reverse mapping ***************************/
3276
3277 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3278 {
3279 num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3280 return num ? num : -EDOM;
3281 }
3282
3283 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3284 {
3285 short *nums = func->interfaces_nums;
3286 unsigned count = func->ffs->interfaces_count;
3287
3288 for (; count; --count, ++nums) {
3289 if (*nums >= 0 && *nums == intf)
3290 return nums - func->interfaces_nums;
3291 }
3292
3293 return -EDOM;
3294 }
3295
3296
3297 /* Devices management *******************************************************/
3298
3299 static LIST_HEAD(ffs_devices);
3300
3301 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3302 {
3303 struct ffs_dev *dev;
3304
3305 list_for_each_entry(dev, &ffs_devices, entry) {
3306 if (!dev->name || !name)
3307 continue;
3308 if (strcmp(dev->name, name) == 0)
3309 return dev;
3310 }
3311
3312 return NULL;
3313 }
3314
3315 /*
3316 * ffs_lock must be taken by the caller of this function
3317 */
3318 static struct ffs_dev *_ffs_get_single_dev(void)
3319 {
3320 struct ffs_dev *dev;
3321
3322 if (list_is_singular(&ffs_devices)) {
3323 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3324 if (dev->single)
3325 return dev;
3326 }
3327
3328 return NULL;
3329 }
3330
3331 /*
3332 * ffs_lock must be taken by the caller of this function
3333 */
3334 static struct ffs_dev *_ffs_find_dev(const char *name)
3335 {
3336 struct ffs_dev *dev;
3337
3338 dev = _ffs_get_single_dev();
3339 if (dev)
3340 return dev;
3341
3342 return _ffs_do_find_dev(name);
3343 }
3344
3345 /* Configfs support *********************************************************/
3346
3347 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3348 {
3349 return container_of(to_config_group(item), struct f_fs_opts,
3350 func_inst.group);
3351 }
3352
3353 static void ffs_attr_release(struct config_item *item)
3354 {
3355 struct f_fs_opts *opts = to_ffs_opts(item);
3356
3357 usb_put_function_instance(&opts->func_inst);
3358 }
3359
3360 static struct configfs_item_operations ffs_item_ops = {
3361 .release = ffs_attr_release,
3362 };
3363
3364 static struct config_item_type ffs_func_type = {
3365 .ct_item_ops = &ffs_item_ops,
3366 .ct_owner = THIS_MODULE,
3367 };
3368
3369
3370 /* Function registration interface ******************************************/
3371
3372 static void ffs_free_inst(struct usb_function_instance *f)
3373 {
3374 struct f_fs_opts *opts;
3375
3376 opts = to_f_fs_opts(f);
3377 ffs_dev_lock();
3378 _ffs_free_dev(opts->dev);
3379 ffs_dev_unlock();
3380 kfree(opts);
3381 }
3382
3383 #define MAX_INST_NAME_LEN 40
3384
3385 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3386 {
3387 struct f_fs_opts *opts;
3388 char *ptr;
3389 const char *tmp;
3390 int name_len, ret;
3391
3392 name_len = strlen(name) + 1;
3393 if (name_len > MAX_INST_NAME_LEN)
3394 return -ENAMETOOLONG;
3395
3396 ptr = kstrndup(name, name_len, GFP_KERNEL);
3397 if (!ptr)
3398 return -ENOMEM;
3399
3400 opts = to_f_fs_opts(fi);
3401 tmp = NULL;
3402
3403 ffs_dev_lock();
3404
3405 tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
3406 ret = _ffs_name_dev(opts->dev, ptr);
3407 if (ret) {
3408 kfree(ptr);
3409 ffs_dev_unlock();
3410 return ret;
3411 }
3412 opts->dev->name_allocated = true;
3413
3414 ffs_dev_unlock();
3415
3416 kfree(tmp);
3417
3418 return 0;
3419 }
3420
3421 static struct usb_function_instance *ffs_alloc_inst(void)
3422 {
3423 struct f_fs_opts *opts;
3424 struct ffs_dev *dev;
3425
3426 opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3427 if (!opts)
3428 return ERR_PTR(-ENOMEM);
3429
3430 opts->func_inst.set_inst_name = ffs_set_inst_name;
3431 opts->func_inst.free_func_inst = ffs_free_inst;
3432 ffs_dev_lock();
3433 dev = _ffs_alloc_dev();
3434 ffs_dev_unlock();
3435 if (IS_ERR(dev)) {
3436 kfree(opts);
3437 return ERR_CAST(dev);
3438 }
3439 opts->dev = dev;
3440 dev->opts = opts;
3441
3442 config_group_init_type_name(&opts->func_inst.group, "",
3443 &ffs_func_type);
3444 return &opts->func_inst;
3445 }
3446
3447 static void ffs_free(struct usb_function *f)
3448 {
3449 kfree(ffs_func_from_usb(f));
3450 }
3451
3452 static void ffs_func_unbind(struct usb_configuration *c,
3453 struct usb_function *f)
3454 {
3455 struct ffs_function *func = ffs_func_from_usb(f);
3456 struct ffs_data *ffs = func->ffs;
3457 struct f_fs_opts *opts =
3458 container_of(f->fi, struct f_fs_opts, func_inst);
3459 struct ffs_ep *ep = func->eps;
3460 unsigned count = ffs->eps_count;
3461 unsigned long flags;
3462
3463 ENTER();
3464 if (ffs->func == func) {
3465 ffs_func_eps_disable(func);
3466 ffs->func = NULL;
3467 }
3468
3469 if (!--opts->refcnt)
3470 functionfs_unbind(ffs);
3471
3472 /* cleanup after autoconfig */
3473 spin_lock_irqsave(&func->ffs->eps_lock, flags);
3474 while (count--) {
3475 if (ep->ep && ep->req)
3476 usb_ep_free_request(ep->ep, ep->req);
3477 ep->req = NULL;
3478 ++ep;
3479 }
3480 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3481 kfree(func->eps);
3482 func->eps = NULL;
3483 /*
3484 * eps, descriptors and interfaces_nums are allocated in the
3485 * same chunk so only one free is required.
3486 */
3487 func->function.fs_descriptors = NULL;
3488 func->function.hs_descriptors = NULL;
3489 func->function.ss_descriptors = NULL;
3490 func->interfaces_nums = NULL;
3491
3492 ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3493 }
3494
3495 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3496 {
3497 struct ffs_function *func;
3498
3499 ENTER();
3500
3501 func = kzalloc(sizeof(*func), GFP_KERNEL);
3502 if (unlikely(!func))
3503 return ERR_PTR(-ENOMEM);
3504
3505 func->function.name = "Function FS Gadget";
3506
3507 func->function.bind = ffs_func_bind;
3508 func->function.unbind = ffs_func_unbind;
3509 func->function.set_alt = ffs_func_set_alt;
3510 func->function.disable = ffs_func_disable;
3511 func->function.setup = ffs_func_setup;
3512 func->function.req_match = ffs_func_req_match;
3513 func->function.suspend = ffs_func_suspend;
3514 func->function.resume = ffs_func_resume;
3515 func->function.free_func = ffs_free;
3516
3517 return &func->function;
3518 }
3519
3520 /*
3521 * ffs_lock must be taken by the caller of this function
3522 */
3523 static struct ffs_dev *_ffs_alloc_dev(void)
3524 {
3525 struct ffs_dev *dev;
3526 int ret;
3527
3528 if (_ffs_get_single_dev())
3529 return ERR_PTR(-EBUSY);
3530
3531 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3532 if (!dev)
3533 return ERR_PTR(-ENOMEM);
3534
3535 if (list_empty(&ffs_devices)) {
3536 ret = functionfs_init();
3537 if (ret) {
3538 kfree(dev);
3539 return ERR_PTR(ret);
3540 }
3541 }
3542
3543 list_add(&dev->entry, &ffs_devices);
3544
3545 return dev;
3546 }
3547
3548 /*
3549 * ffs_lock must be taken by the caller of this function
3550 * The caller is responsible for "name" being available whenever f_fs needs it
3551 */
3552 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
3553 {
3554 struct ffs_dev *existing;
3555
3556 existing = _ffs_do_find_dev(name);
3557 if (existing)
3558 return -EBUSY;
3559
3560 dev->name = name;
3561
3562 return 0;
3563 }
3564
3565 /*
3566 * The caller is responsible for "name" being available whenever f_fs needs it
3567 */
3568 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3569 {
3570 int ret;
3571
3572 ffs_dev_lock();
3573 ret = _ffs_name_dev(dev, name);
3574 ffs_dev_unlock();
3575
3576 return ret;
3577 }
3578 EXPORT_SYMBOL_GPL(ffs_name_dev);
3579
3580 int ffs_single_dev(struct ffs_dev *dev)
3581 {
3582 int ret;
3583
3584 ret = 0;
3585 ffs_dev_lock();
3586
3587 if (!list_is_singular(&ffs_devices))
3588 ret = -EBUSY;
3589 else
3590 dev->single = true;
3591
3592 ffs_dev_unlock();
3593 return ret;
3594 }
3595 EXPORT_SYMBOL_GPL(ffs_single_dev);
3596
3597 /*
3598 * ffs_lock must be taken by the caller of this function
3599 */
3600 static void _ffs_free_dev(struct ffs_dev *dev)
3601 {
3602 list_del(&dev->entry);
3603 if (dev->name_allocated)
3604 kfree(dev->name);
3605
3606 /* Clear the private_data pointer to stop incorrect dev access */
3607 if (dev->ffs_data)
3608 dev->ffs_data->private_data = NULL;
3609
3610 kfree(dev);
3611 if (list_empty(&ffs_devices))
3612 functionfs_cleanup();
3613 }
3614
3615 static void *ffs_acquire_dev(const char *dev_name)
3616 {
3617 struct ffs_dev *ffs_dev;
3618
3619 ENTER();
3620 ffs_dev_lock();
3621
3622 ffs_dev = _ffs_find_dev(dev_name);
3623 if (!ffs_dev)
3624 ffs_dev = ERR_PTR(-ENOENT);
3625 else if (ffs_dev->mounted)
3626 ffs_dev = ERR_PTR(-EBUSY);
3627 else if (ffs_dev->ffs_acquire_dev_callback &&
3628 ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3629 ffs_dev = ERR_PTR(-ENOENT);
3630 else
3631 ffs_dev->mounted = true;
3632
3633 ffs_dev_unlock();
3634 return ffs_dev;
3635 }
3636
3637 static void ffs_release_dev(struct ffs_data *ffs_data)
3638 {
3639 struct ffs_dev *ffs_dev;
3640
3641 ENTER();
3642 ffs_dev_lock();
3643
3644 ffs_dev = ffs_data->private_data;
3645 if (ffs_dev) {
3646 ffs_dev->mounted = false;
3647
3648 if (ffs_dev->ffs_release_dev_callback)
3649 ffs_dev->ffs_release_dev_callback(ffs_dev);
3650 }
3651
3652 ffs_dev_unlock();
3653 }
3654
3655 static int ffs_ready(struct ffs_data *ffs)
3656 {
3657 struct ffs_dev *ffs_obj;
3658 int ret = 0;
3659
3660 ENTER();
3661 ffs_dev_lock();
3662
3663 ffs_obj = ffs->private_data;
3664 if (!ffs_obj) {
3665 ret = -EINVAL;
3666 goto done;
3667 }
3668 if (WARN_ON(ffs_obj->desc_ready)) {
3669 ret = -EBUSY;
3670 goto done;
3671 }
3672
3673 ffs_obj->desc_ready = true;
3674 ffs_obj->ffs_data = ffs;
3675
3676 if (ffs_obj->ffs_ready_callback) {
3677 ret = ffs_obj->ffs_ready_callback(ffs);
3678 if (ret)
3679 goto done;
3680 }
3681
3682 set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3683 done:
3684 ffs_dev_unlock();
3685 return ret;
3686 }
3687
3688 static void ffs_closed(struct ffs_data *ffs)
3689 {
3690 struct ffs_dev *ffs_obj;
3691 struct f_fs_opts *opts;
3692 struct config_item *ci;
3693
3694 ENTER();
3695 ffs_dev_lock();
3696
3697 ffs_obj = ffs->private_data;
3698 if (!ffs_obj)
3699 goto done;
3700
3701 ffs_obj->desc_ready = false;
3702
3703 if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3704 ffs_obj->ffs_closed_callback)
3705 ffs_obj->ffs_closed_callback(ffs);
3706
3707 if (ffs_obj->opts)
3708 opts = ffs_obj->opts;
3709 else
3710 goto done;
3711
3712 if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3713 || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3714 goto done;
3715
3716 ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3717 ffs_dev_unlock();
3718
3719 unregister_gadget_item(ci);
3720 return;
3721 done:
3722 ffs_dev_unlock();
3723 }
3724
3725 /* Misc helper functions ****************************************************/
3726
3727 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3728 {
3729 return nonblock
3730 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3731 : mutex_lock_interruptible(mutex);
3732 }
3733
3734 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3735 {
3736 char *data;
3737
3738 if (unlikely(!len))
3739 return NULL;
3740
3741 data = kmalloc(len, GFP_KERNEL);
3742 if (unlikely(!data))
3743 return ERR_PTR(-ENOMEM);
3744
3745 if (unlikely(copy_from_user(data, buf, len))) {
3746 kfree(data);
3747 return ERR_PTR(-EFAULT);
3748 }
3749
3750 pr_vdebug("Buffer from user space:\n");
3751 ffs_dump_mem("", data, len);
3752
3753 return data;
3754 }
3755
3756 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3757 MODULE_LICENSE("GPL");
3758 MODULE_AUTHOR("Michal Nazarewicz");