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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * f_fs.c -- user mode file system API for USB composite function controllers
4 *
5 * Copyright (C) 2010 Samsung Electronics
6 * Author: Michal Nazarewicz <mina86@mina86.com>
7 *
8 * Based on inode.c (GadgetFS) which was:
9 * Copyright (C) 2003-2004 David Brownell
10 * Copyright (C) 2003 Agilent Technologies
11 */
12
13
14/* #define DEBUG */
15/* #define VERBOSE_DEBUG */
16
17#include <linux/blkdev.h>
18#include <linux/pagemap.h>
19#include <linux/export.h>
20#include <linux/fs_parser.h>
21#include <linux/hid.h>
22#include <linux/mm.h>
23#include <linux/module.h>
24#include <linux/scatterlist.h>
25#include <linux/sched/signal.h>
26#include <linux/uio.h>
27#include <linux/vmalloc.h>
28#include <asm/unaligned.h>
29
30#include <linux/usb/ccid.h>
31#include <linux/usb/composite.h>
32#include <linux/usb/functionfs.h>
33
34#include <linux/aio.h>
35#include <linux/mmu_context.h>
36#include <linux/poll.h>
37#include <linux/eventfd.h>
38
39#include "u_fs.h"
40#include "u_f.h"
41#include "u_os_desc.h"
42#include "configfs.h"
43
44#define FUNCTIONFS_MAGIC 0xa647361 /* Chosen by a honest dice roll ;) */
45
46/* Reference counter handling */
47static void ffs_data_get(struct ffs_data *ffs);
48static void ffs_data_put(struct ffs_data *ffs);
49/* Creates new ffs_data object. */
50static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
51 __attribute__((malloc));
52
53/* Opened counter handling. */
54static void ffs_data_opened(struct ffs_data *ffs);
55static void ffs_data_closed(struct ffs_data *ffs);
56
57/* Called with ffs->mutex held; take over ownership of data. */
58static int __must_check
59__ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
60static int __must_check
61__ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
62
63
64/* The function structure ***************************************************/
65
66struct ffs_ep;
67
68struct ffs_function {
69 struct usb_configuration *conf;
70 struct usb_gadget *gadget;
71 struct ffs_data *ffs;
72
73 struct ffs_ep *eps;
74 u8 eps_revmap[16];
75 short *interfaces_nums;
76
77 struct usb_function function;
78};
79
80
81static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
82{
83 return container_of(f, struct ffs_function, function);
84}
85
86
87static inline enum ffs_setup_state
88ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
89{
90 return (enum ffs_setup_state)
91 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
92}
93
94
95static void ffs_func_eps_disable(struct ffs_function *func);
96static int __must_check ffs_func_eps_enable(struct ffs_function *func);
97
98static int ffs_func_bind(struct usb_configuration *,
99 struct usb_function *);
100static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
101static void ffs_func_disable(struct usb_function *);
102static int ffs_func_setup(struct usb_function *,
103 const struct usb_ctrlrequest *);
104static bool ffs_func_req_match(struct usb_function *,
105 const struct usb_ctrlrequest *,
106 bool config0);
107static void ffs_func_suspend(struct usb_function *);
108static void ffs_func_resume(struct usb_function *);
109
110
111static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
112static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
113
114
115/* The endpoints structures *************************************************/
116
117struct ffs_ep {
118 struct usb_ep *ep; /* P: ffs->eps_lock */
119 struct usb_request *req; /* P: epfile->mutex */
120
121 /* [0]: full speed, [1]: high speed, [2]: super speed */
122 struct usb_endpoint_descriptor *descs[3];
123
124 u8 num;
125
126 int status; /* P: epfile->mutex */
127};
128
129struct ffs_epfile {
130 /* Protects ep->ep and ep->req. */
131 struct mutex mutex;
132
133 struct ffs_data *ffs;
134 struct ffs_ep *ep; /* P: ffs->eps_lock */
135
136 struct dentry *dentry;
137
138 /*
139 * Buffer for holding data from partial reads which may happen since
140 * we’re rounding user read requests to a multiple of a max packet size.
141 *
142 * The pointer is initialised with NULL value and may be set by
143 * __ffs_epfile_read_data function to point to a temporary buffer.
144 *
145 * In normal operation, calls to __ffs_epfile_read_buffered will consume
146 * data from said buffer and eventually free it. Importantly, while the
147 * function is using the buffer, it sets the pointer to NULL. This is
148 * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
149 * can never run concurrently (they are synchronised by epfile->mutex)
150 * so the latter will not assign a new value to the pointer.
151 *
152 * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
153 * valid) and sets the pointer to READ_BUFFER_DROP value. This special
154 * value is crux of the synchronisation between ffs_func_eps_disable and
155 * __ffs_epfile_read_data.
156 *
157 * Once __ffs_epfile_read_data is about to finish it will try to set the
158 * pointer back to its old value (as described above), but seeing as the
159 * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
160 * the buffer.
161 *
162 * == State transitions ==
163 *
164 * • ptr == NULL: (initial state)
165 * â—¦ __ffs_epfile_read_buffer_free: go to ptr == DROP
166 * â—¦ __ffs_epfile_read_buffered: nop
167 * â—¦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
168 * ◦ reading finishes: n/a, not in ‘and reading’ state
169 * • ptr == DROP:
170 * â—¦ __ffs_epfile_read_buffer_free: nop
171 * â—¦ __ffs_epfile_read_buffered: go to ptr == NULL
172 * â—¦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
173 * ◦ reading finishes: n/a, not in ‘and reading’ state
174 * • ptr == buf:
175 * â—¦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
176 * â—¦ __ffs_epfile_read_buffered: go to ptr == NULL and reading
177 * â—¦ __ffs_epfile_read_data: n/a, __ffs_epfile_read_buffered
178 * is always called first
179 * ◦ reading finishes: n/a, not in ‘and reading’ state
180 * • ptr == NULL and reading:
181 * â—¦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
182 * â—¦ __ffs_epfile_read_buffered: n/a, mutex is held
183 * â—¦ __ffs_epfile_read_data: n/a, mutex is held
184 * ◦ reading finishes and …
185 * … all data read: free buf, go to ptr == NULL
186 * … otherwise: go to ptr == buf and reading
187 * • ptr == DROP and reading:
188 * â—¦ __ffs_epfile_read_buffer_free: nop
189 * â—¦ __ffs_epfile_read_buffered: n/a, mutex is held
190 * â—¦ __ffs_epfile_read_data: n/a, mutex is held
191 * â—¦ reading finishes: free buf, go to ptr == DROP
192 */
193 struct ffs_buffer *read_buffer;
194#define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
195
196 char name[5];
197
198 unsigned char in; /* P: ffs->eps_lock */
199 unsigned char isoc; /* P: ffs->eps_lock */
200
201 unsigned char _pad;
202};
203
204struct ffs_buffer {
205 size_t length;
206 char *data;
207 char storage[];
208};
209
210/* ffs_io_data structure ***************************************************/
211
212struct ffs_io_data {
213 bool aio;
214 bool read;
215
216 struct kiocb *kiocb;
217 struct iov_iter data;
218 const void *to_free;
219 char *buf;
220
221 struct mm_struct *mm;
222 struct work_struct work;
223
224 struct usb_ep *ep;
225 struct usb_request *req;
226 struct sg_table sgt;
227 bool use_sg;
228
229 struct ffs_data *ffs;
230};
231
232struct ffs_desc_helper {
233 struct ffs_data *ffs;
234 unsigned interfaces_count;
235 unsigned eps_count;
236};
237
238static int __must_check ffs_epfiles_create(struct ffs_data *ffs);
239static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
240
241static struct dentry *
242ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
243 const struct file_operations *fops);
244
245/* Devices management *******************************************************/
246
247DEFINE_MUTEX(ffs_lock);
248EXPORT_SYMBOL_GPL(ffs_lock);
249
250static struct ffs_dev *_ffs_find_dev(const char *name);
251static struct ffs_dev *_ffs_alloc_dev(void);
252static void _ffs_free_dev(struct ffs_dev *dev);
253static void *ffs_acquire_dev(const char *dev_name);
254static void ffs_release_dev(struct ffs_data *ffs_data);
255static int ffs_ready(struct ffs_data *ffs);
256static void ffs_closed(struct ffs_data *ffs);
257
258/* Misc helper functions ****************************************************/
259
260static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
261 __attribute__((warn_unused_result, nonnull));
262static char *ffs_prepare_buffer(const char __user *buf, size_t len)
263 __attribute__((warn_unused_result, nonnull));
264
265
266/* Control file aka ep0 *****************************************************/
267
268static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
269{
270 struct ffs_data *ffs = req->context;
271
272 complete(&ffs->ep0req_completion);
273}
274
275static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
276 __releases(&ffs->ev.waitq.lock)
277{
278 struct usb_request *req = ffs->ep0req;
279 int ret;
280
281 req->zero = len < le16_to_cpu(ffs->ev.setup.wLength);
282
283 spin_unlock_irq(&ffs->ev.waitq.lock);
284
285 req->buf = data;
286 req->length = len;
287
288 /*
289 * UDC layer requires to provide a buffer even for ZLP, but should
290 * not use it at all. Let's provide some poisoned pointer to catch
291 * possible bug in the driver.
292 */
293 if (req->buf == NULL)
294 req->buf = (void *)0xDEADBABE;
295
296 reinit_completion(&ffs->ep0req_completion);
297
298 ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
299 if (unlikely(ret < 0))
300 return ret;
301
302 ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
303 if (unlikely(ret)) {
304 usb_ep_dequeue(ffs->gadget->ep0, req);
305 return -EINTR;
306 }
307
308 ffs->setup_state = FFS_NO_SETUP;
309 return req->status ? req->status : req->actual;
310}
311
312static int __ffs_ep0_stall(struct ffs_data *ffs)
313{
314 if (ffs->ev.can_stall) {
315 pr_vdebug("ep0 stall\n");
316 usb_ep_set_halt(ffs->gadget->ep0);
317 ffs->setup_state = FFS_NO_SETUP;
318 return -EL2HLT;
319 } else {
320 pr_debug("bogus ep0 stall!\n");
321 return -ESRCH;
322 }
323}
324
325static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
326 size_t len, loff_t *ptr)
327{
328 struct ffs_data *ffs = file->private_data;
329 ssize_t ret;
330 char *data;
331
332 ENTER();
333
334 /* Fast check if setup was canceled */
335 if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
336 return -EIDRM;
337
338 /* Acquire mutex */
339 ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
340 if (unlikely(ret < 0))
341 return ret;
342
343 /* Check state */
344 switch (ffs->state) {
345 case FFS_READ_DESCRIPTORS:
346 case FFS_READ_STRINGS:
347 /* Copy data */
348 if (unlikely(len < 16)) {
349 ret = -EINVAL;
350 break;
351 }
352
353 data = ffs_prepare_buffer(buf, len);
354 if (IS_ERR(data)) {
355 ret = PTR_ERR(data);
356 break;
357 }
358
359 /* Handle data */
360 if (ffs->state == FFS_READ_DESCRIPTORS) {
361 pr_info("read descriptors\n");
362 ret = __ffs_data_got_descs(ffs, data, len);
363 if (unlikely(ret < 0))
364 break;
365
366 ffs->state = FFS_READ_STRINGS;
367 ret = len;
368 } else {
369 pr_info("read strings\n");
370 ret = __ffs_data_got_strings(ffs, data, len);
371 if (unlikely(ret < 0))
372 break;
373
374 ret = ffs_epfiles_create(ffs);
375 if (unlikely(ret)) {
376 ffs->state = FFS_CLOSING;
377 break;
378 }
379
380 ffs->state = FFS_ACTIVE;
381 mutex_unlock(&ffs->mutex);
382
383 ret = ffs_ready(ffs);
384 if (unlikely(ret < 0)) {
385 ffs->state = FFS_CLOSING;
386 return ret;
387 }
388
389 return len;
390 }
391 break;
392
393 case FFS_ACTIVE:
394 data = NULL;
395 /*
396 * We're called from user space, we can use _irq
397 * rather then _irqsave
398 */
399 spin_lock_irq(&ffs->ev.waitq.lock);
400 switch (ffs_setup_state_clear_cancelled(ffs)) {
401 case FFS_SETUP_CANCELLED:
402 ret = -EIDRM;
403 goto done_spin;
404
405 case FFS_NO_SETUP:
406 ret = -ESRCH;
407 goto done_spin;
408
409 case FFS_SETUP_PENDING:
410 break;
411 }
412
413 /* FFS_SETUP_PENDING */
414 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
415 spin_unlock_irq(&ffs->ev.waitq.lock);
416 ret = __ffs_ep0_stall(ffs);
417 break;
418 }
419
420 /* FFS_SETUP_PENDING and not stall */
421 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
422
423 spin_unlock_irq(&ffs->ev.waitq.lock);
424
425 data = ffs_prepare_buffer(buf, len);
426 if (IS_ERR(data)) {
427 ret = PTR_ERR(data);
428 break;
429 }
430
431 spin_lock_irq(&ffs->ev.waitq.lock);
432
433 /*
434 * We are guaranteed to be still in FFS_ACTIVE state
435 * but the state of setup could have changed from
436 * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
437 * to check for that. If that happened we copied data
438 * from user space in vain but it's unlikely.
439 *
440 * For sure we are not in FFS_NO_SETUP since this is
441 * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
442 * transition can be performed and it's protected by
443 * mutex.
444 */
445 if (ffs_setup_state_clear_cancelled(ffs) ==
446 FFS_SETUP_CANCELLED) {
447 ret = -EIDRM;
448done_spin:
449 spin_unlock_irq(&ffs->ev.waitq.lock);
450 } else {
451 /* unlocks spinlock */
452 ret = __ffs_ep0_queue_wait(ffs, data, len);
453 }
454 kfree(data);
455 break;
456
457 default:
458 ret = -EBADFD;
459 break;
460 }
461
462 mutex_unlock(&ffs->mutex);
463 return ret;
464}
465
466/* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
467static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
468 size_t n)
469 __releases(&ffs->ev.waitq.lock)
470{
471 /*
472 * n cannot be bigger than ffs->ev.count, which cannot be bigger than
473 * size of ffs->ev.types array (which is four) so that's how much space
474 * we reserve.
475 */
476 struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
477 const size_t size = n * sizeof *events;
478 unsigned i = 0;
479
480 memset(events, 0, size);
481
482 do {
483 events[i].type = ffs->ev.types[i];
484 if (events[i].type == FUNCTIONFS_SETUP) {
485 events[i].u.setup = ffs->ev.setup;
486 ffs->setup_state = FFS_SETUP_PENDING;
487 }
488 } while (++i < n);
489
490 ffs->ev.count -= n;
491 if (ffs->ev.count)
492 memmove(ffs->ev.types, ffs->ev.types + n,
493 ffs->ev.count * sizeof *ffs->ev.types);
494
495 spin_unlock_irq(&ffs->ev.waitq.lock);
496 mutex_unlock(&ffs->mutex);
497
498 return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
499}
500
501static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
502 size_t len, loff_t *ptr)
503{
504 struct ffs_data *ffs = file->private_data;
505 char *data = NULL;
506 size_t n;
507 int ret;
508
509 ENTER();
510
511 /* Fast check if setup was canceled */
512 if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
513 return -EIDRM;
514
515 /* Acquire mutex */
516 ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
517 if (unlikely(ret < 0))
518 return ret;
519
520 /* Check state */
521 if (ffs->state != FFS_ACTIVE) {
522 ret = -EBADFD;
523 goto done_mutex;
524 }
525
526 /*
527 * We're called from user space, we can use _irq rather then
528 * _irqsave
529 */
530 spin_lock_irq(&ffs->ev.waitq.lock);
531
532 switch (ffs_setup_state_clear_cancelled(ffs)) {
533 case FFS_SETUP_CANCELLED:
534 ret = -EIDRM;
535 break;
536
537 case FFS_NO_SETUP:
538 n = len / sizeof(struct usb_functionfs_event);
539 if (unlikely(!n)) {
540 ret = -EINVAL;
541 break;
542 }
543
544 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
545 ret = -EAGAIN;
546 break;
547 }
548
549 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
550 ffs->ev.count)) {
551 ret = -EINTR;
552 break;
553 }
554
555 /* unlocks spinlock */
556 return __ffs_ep0_read_events(ffs, buf,
557 min(n, (size_t)ffs->ev.count));
558
559 case FFS_SETUP_PENDING:
560 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
561 spin_unlock_irq(&ffs->ev.waitq.lock);
562 ret = __ffs_ep0_stall(ffs);
563 goto done_mutex;
564 }
565
566 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
567
568 spin_unlock_irq(&ffs->ev.waitq.lock);
569
570 if (likely(len)) {
571 data = kmalloc(len, GFP_KERNEL);
572 if (unlikely(!data)) {
573 ret = -ENOMEM;
574 goto done_mutex;
575 }
576 }
577
578 spin_lock_irq(&ffs->ev.waitq.lock);
579
580 /* See ffs_ep0_write() */
581 if (ffs_setup_state_clear_cancelled(ffs) ==
582 FFS_SETUP_CANCELLED) {
583 ret = -EIDRM;
584 break;
585 }
586
587 /* unlocks spinlock */
588 ret = __ffs_ep0_queue_wait(ffs, data, len);
589 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
590 ret = -EFAULT;
591 goto done_mutex;
592
593 default:
594 ret = -EBADFD;
595 break;
596 }
597
598 spin_unlock_irq(&ffs->ev.waitq.lock);
599done_mutex:
600 mutex_unlock(&ffs->mutex);
601 kfree(data);
602 return ret;
603}
604
605static int ffs_ep0_open(struct inode *inode, struct file *file)
606{
607 struct ffs_data *ffs = inode->i_private;
608
609 ENTER();
610
611 if (unlikely(ffs->state == FFS_CLOSING))
612 return -EBUSY;
613
614 file->private_data = ffs;
615 ffs_data_opened(ffs);
616
617 return 0;
618}
619
620static int ffs_ep0_release(struct inode *inode, struct file *file)
621{
622 struct ffs_data *ffs = file->private_data;
623
624 ENTER();
625
626 ffs_data_closed(ffs);
627
628 return 0;
629}
630
631static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
632{
633 struct ffs_data *ffs = file->private_data;
634 struct usb_gadget *gadget = ffs->gadget;
635 long ret;
636
637 ENTER();
638
639 if (code == FUNCTIONFS_INTERFACE_REVMAP) {
640 struct ffs_function *func = ffs->func;
641 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
642 } else if (gadget && gadget->ops->ioctl) {
643 ret = gadget->ops->ioctl(gadget, code, value);
644 } else {
645 ret = -ENOTTY;
646 }
647
648 return ret;
649}
650
651static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
652{
653 struct ffs_data *ffs = file->private_data;
654 __poll_t mask = EPOLLWRNORM;
655 int ret;
656
657 poll_wait(file, &ffs->ev.waitq, wait);
658
659 ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
660 if (unlikely(ret < 0))
661 return mask;
662
663 switch (ffs->state) {
664 case FFS_READ_DESCRIPTORS:
665 case FFS_READ_STRINGS:
666 mask |= EPOLLOUT;
667 break;
668
669 case FFS_ACTIVE:
670 switch (ffs->setup_state) {
671 case FFS_NO_SETUP:
672 if (ffs->ev.count)
673 mask |= EPOLLIN;
674 break;
675
676 case FFS_SETUP_PENDING:
677 case FFS_SETUP_CANCELLED:
678 mask |= (EPOLLIN | EPOLLOUT);
679 break;
680 }
681 case FFS_CLOSING:
682 break;
683 case FFS_DEACTIVATED:
684 break;
685 }
686
687 mutex_unlock(&ffs->mutex);
688
689 return mask;
690}
691
692static const struct file_operations ffs_ep0_operations = {
693 .llseek = no_llseek,
694
695 .open = ffs_ep0_open,
696 .write = ffs_ep0_write,
697 .read = ffs_ep0_read,
698 .release = ffs_ep0_release,
699 .unlocked_ioctl = ffs_ep0_ioctl,
700 .poll = ffs_ep0_poll,
701};
702
703
704/* "Normal" endpoints operations ********************************************/
705
706static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
707{
708 ENTER();
709 if (likely(req->context)) {
710 struct ffs_ep *ep = _ep->driver_data;
711 ep->status = req->status ? req->status : req->actual;
712 complete(req->context);
713 }
714}
715
716static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
717{
718 ssize_t ret = copy_to_iter(data, data_len, iter);
719 if (likely(ret == data_len))
720 return ret;
721
722 if (unlikely(iov_iter_count(iter)))
723 return -EFAULT;
724
725 /*
726 * Dear user space developer!
727 *
728 * TL;DR: To stop getting below error message in your kernel log, change
729 * user space code using functionfs to align read buffers to a max
730 * packet size.
731 *
732 * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
733 * packet size. When unaligned buffer is passed to functionfs, it
734 * internally uses a larger, aligned buffer so that such UDCs are happy.
735 *
736 * Unfortunately, this means that host may send more data than was
737 * requested in read(2) system call. f_fs doesn’t know what to do with
738 * that excess data so it simply drops it.
739 *
740 * Was the buffer aligned in the first place, no such problem would
741 * happen.
742 *
743 * Data may be dropped only in AIO reads. Synchronous reads are handled
744 * by splitting a request into multiple parts. This splitting may still
745 * be a problem though so it’s likely best to align the buffer
746 * regardless of it being AIO or not..
747 *
748 * This only affects OUT endpoints, i.e. reading data with a read(2),
749 * aio_read(2) etc. system calls. Writing data to an IN endpoint is not
750 * affected.
751 */
752 pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
753 "Align read buffer size to max packet size to avoid the problem.\n",
754 data_len, ret);
755
756 return ret;
757}
758
759/*
760 * allocate a virtually contiguous buffer and create a scatterlist describing it
761 * @sg_table - pointer to a place to be filled with sg_table contents
762 * @size - required buffer size
763 */
764static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
765{
766 struct page **pages;
767 void *vaddr, *ptr;
768 unsigned int n_pages;
769 int i;
770
771 vaddr = vmalloc(sz);
772 if (!vaddr)
773 return NULL;
774
775 n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
776 pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
777 if (!pages) {
778 vfree(vaddr);
779
780 return NULL;
781 }
782 for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
783 pages[i] = vmalloc_to_page(ptr);
784
785 if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
786 kvfree(pages);
787 vfree(vaddr);
788
789 return NULL;
790 }
791 kvfree(pages);
792
793 return vaddr;
794}
795
796static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
797 size_t data_len)
798{
799 if (io_data->use_sg)
800 return ffs_build_sg_list(&io_data->sgt, data_len);
801
802 return kmalloc(data_len, GFP_KERNEL);
803}
804
805static inline void ffs_free_buffer(struct ffs_io_data *io_data)
806{
807 if (!io_data->buf)
808 return;
809
810 if (io_data->use_sg) {
811 sg_free_table(&io_data->sgt);
812 vfree(io_data->buf);
813 } else {
814 kfree(io_data->buf);
815 }
816}
817
818static void ffs_user_copy_worker(struct work_struct *work)
819{
820 struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
821 work);
822 int ret = io_data->req->status ? io_data->req->status :
823 io_data->req->actual;
824 bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
825
826 if (io_data->read && ret > 0) {
827 mm_segment_t oldfs = get_fs();
828
829 set_fs(USER_DS);
830 use_mm(io_data->mm);
831 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
832 unuse_mm(io_data->mm);
833 set_fs(oldfs);
834 }
835
836 io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
837
838 if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
839 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
840
841 usb_ep_free_request(io_data->ep, io_data->req);
842
843 if (io_data->read)
844 kfree(io_data->to_free);
845 ffs_free_buffer(io_data);
846 kfree(io_data);
847}
848
849static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
850 struct usb_request *req)
851{
852 struct ffs_io_data *io_data = req->context;
853 struct ffs_data *ffs = io_data->ffs;
854
855 ENTER();
856
857 INIT_WORK(&io_data->work, ffs_user_copy_worker);
858 queue_work(ffs->io_completion_wq, &io_data->work);
859}
860
861static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
862{
863 /*
864 * See comment in struct ffs_epfile for full read_buffer pointer
865 * synchronisation story.
866 */
867 struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
868 if (buf && buf != READ_BUFFER_DROP)
869 kfree(buf);
870}
871
872/* Assumes epfile->mutex is held. */
873static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
874 struct iov_iter *iter)
875{
876 /*
877 * Null out epfile->read_buffer so ffs_func_eps_disable does not free
878 * the buffer while we are using it. See comment in struct ffs_epfile
879 * for full read_buffer pointer synchronisation story.
880 */
881 struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
882 ssize_t ret;
883 if (!buf || buf == READ_BUFFER_DROP)
884 return 0;
885
886 ret = copy_to_iter(buf->data, buf->length, iter);
887 if (buf->length == ret) {
888 kfree(buf);
889 return ret;
890 }
891
892 if (unlikely(iov_iter_count(iter))) {
893 ret = -EFAULT;
894 } else {
895 buf->length -= ret;
896 buf->data += ret;
897 }
898
899 if (cmpxchg(&epfile->read_buffer, NULL, buf))
900 kfree(buf);
901
902 return ret;
903}
904
905/* Assumes epfile->mutex is held. */
906static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
907 void *data, int data_len,
908 struct iov_iter *iter)
909{
910 struct ffs_buffer *buf;
911
912 ssize_t ret = copy_to_iter(data, data_len, iter);
913 if (likely(data_len == ret))
914 return ret;
915
916 if (unlikely(iov_iter_count(iter)))
917 return -EFAULT;
918
919 /* See ffs_copy_to_iter for more context. */
920 pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
921 data_len, ret);
922
923 data_len -= ret;
924 buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
925 if (!buf)
926 return -ENOMEM;
927 buf->length = data_len;
928 buf->data = buf->storage;
929 memcpy(buf->storage, data + ret, data_len);
930
931 /*
932 * At this point read_buffer is NULL or READ_BUFFER_DROP (if
933 * ffs_func_eps_disable has been called in the meanwhile). See comment
934 * in struct ffs_epfile for full read_buffer pointer synchronisation
935 * story.
936 */
937 if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
938 kfree(buf);
939
940 return ret;
941}
942
943static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
944{
945 struct ffs_epfile *epfile = file->private_data;
946 struct usb_request *req;
947 struct ffs_ep *ep;
948 char *data = NULL;
949 ssize_t ret, data_len = -EINVAL;
950 int halt;
951
952 /* Are we still active? */
953 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
954 return -ENODEV;
955
956 /* Wait for endpoint to be enabled */
957 ep = epfile->ep;
958 if (!ep) {
959 if (file->f_flags & O_NONBLOCK)
960 return -EAGAIN;
961
962 ret = wait_event_interruptible(
963 epfile->ffs->wait, (ep = epfile->ep));
964 if (ret)
965 return -EINTR;
966 }
967
968 /* Do we halt? */
969 halt = (!io_data->read == !epfile->in);
970 if (halt && epfile->isoc)
971 return -EINVAL;
972
973 /* We will be using request and read_buffer */
974 ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
975 if (unlikely(ret))
976 goto error;
977
978 /* Allocate & copy */
979 if (!halt) {
980 struct usb_gadget *gadget;
981
982 /*
983 * Do we have buffered data from previous partial read? Check
984 * that for synchronous case only because we do not have
985 * facility to ‘wake up’ a pending asynchronous read and push
986 * buffered data to it which we would need to make things behave
987 * consistently.
988 */
989 if (!io_data->aio && io_data->read) {
990 ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
991 if (ret)
992 goto error_mutex;
993 }
994
995 /*
996 * if we _do_ wait above, the epfile->ffs->gadget might be NULL
997 * before the waiting completes, so do not assign to 'gadget'
998 * earlier
999 */
1000 gadget = epfile->ffs->gadget;
1001
1002 spin_lock_irq(&epfile->ffs->eps_lock);
1003 /* In the meantime, endpoint got disabled or changed. */
1004 if (epfile->ep != ep) {
1005 ret = -ESHUTDOWN;
1006 goto error_lock;
1007 }
1008 data_len = iov_iter_count(&io_data->data);
1009 /*
1010 * Controller may require buffer size to be aligned to
1011 * maxpacketsize of an out endpoint.
1012 */
1013 if (io_data->read)
1014 data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1015
1016 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1017 spin_unlock_irq(&epfile->ffs->eps_lock);
1018
1019 data = ffs_alloc_buffer(io_data, data_len);
1020 if (unlikely(!data)) {
1021 ret = -ENOMEM;
1022 goto error_mutex;
1023 }
1024 if (!io_data->read &&
1025 !copy_from_iter_full(data, data_len, &io_data->data)) {
1026 ret = -EFAULT;
1027 goto error_mutex;
1028 }
1029 }
1030
1031 spin_lock_irq(&epfile->ffs->eps_lock);
1032
1033 if (epfile->ep != ep) {
1034 /* In the meantime, endpoint got disabled or changed. */
1035 ret = -ESHUTDOWN;
1036 } else if (halt) {
1037 ret = usb_ep_set_halt(ep->ep);
1038 if (!ret)
1039 ret = -EBADMSG;
1040 } else if (unlikely(data_len == -EINVAL)) {
1041 /*
1042 * Sanity Check: even though data_len can't be used
1043 * uninitialized at the time I write this comment, some
1044 * compilers complain about this situation.
1045 * In order to keep the code clean from warnings, data_len is
1046 * being initialized to -EINVAL during its declaration, which
1047 * means we can't rely on compiler anymore to warn no future
1048 * changes won't result in data_len being used uninitialized.
1049 * For such reason, we're adding this redundant sanity check
1050 * here.
1051 */
1052 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1053 ret = -EINVAL;
1054 } else if (!io_data->aio) {
1055 DECLARE_COMPLETION_ONSTACK(done);
1056 bool interrupted = false;
1057
1058 req = ep->req;
1059 if (io_data->use_sg) {
1060 req->buf = NULL;
1061 req->sg = io_data->sgt.sgl;
1062 req->num_sgs = io_data->sgt.nents;
1063 } else {
1064 req->buf = data;
1065 }
1066 req->length = data_len;
1067
1068 io_data->buf = data;
1069
1070 req->context = &done;
1071 req->complete = ffs_epfile_io_complete;
1072
1073 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1074 if (unlikely(ret < 0))
1075 goto error_lock;
1076
1077 spin_unlock_irq(&epfile->ffs->eps_lock);
1078
1079 if (unlikely(wait_for_completion_interruptible(&done))) {
1080 /*
1081 * To avoid race condition with ffs_epfile_io_complete,
1082 * dequeue the request first then check
1083 * status. usb_ep_dequeue API should guarantee no race
1084 * condition with req->complete callback.
1085 */
1086 usb_ep_dequeue(ep->ep, req);
1087 wait_for_completion(&done);
1088 interrupted = ep->status < 0;
1089 }
1090
1091 if (interrupted)
1092 ret = -EINTR;
1093 else if (io_data->read && ep->status > 0)
1094 ret = __ffs_epfile_read_data(epfile, data, ep->status,
1095 &io_data->data);
1096 else
1097 ret = ep->status;
1098 goto error_mutex;
1099 } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1100 ret = -ENOMEM;
1101 } else {
1102 if (io_data->use_sg) {
1103 req->buf = NULL;
1104 req->sg = io_data->sgt.sgl;
1105 req->num_sgs = io_data->sgt.nents;
1106 } else {
1107 req->buf = data;
1108 }
1109 req->length = data_len;
1110
1111 io_data->buf = data;
1112 io_data->ep = ep->ep;
1113 io_data->req = req;
1114 io_data->ffs = epfile->ffs;
1115
1116 req->context = io_data;
1117 req->complete = ffs_epfile_async_io_complete;
1118
1119 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1120 if (unlikely(ret)) {
1121 usb_ep_free_request(ep->ep, req);
1122 goto error_lock;
1123 }
1124
1125 ret = -EIOCBQUEUED;
1126 /*
1127 * Do not kfree the buffer in this function. It will be freed
1128 * by ffs_user_copy_worker.
1129 */
1130 data = NULL;
1131 }
1132
1133error_lock:
1134 spin_unlock_irq(&epfile->ffs->eps_lock);
1135error_mutex:
1136 mutex_unlock(&epfile->mutex);
1137error:
1138 if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1139 ffs_free_buffer(io_data);
1140 return ret;
1141}
1142
1143static int
1144ffs_epfile_open(struct inode *inode, struct file *file)
1145{
1146 struct ffs_epfile *epfile = inode->i_private;
1147
1148 ENTER();
1149
1150 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1151 return -ENODEV;
1152
1153 file->private_data = epfile;
1154 ffs_data_opened(epfile->ffs);
1155
1156 return 0;
1157}
1158
1159static int ffs_aio_cancel(struct kiocb *kiocb)
1160{
1161 struct ffs_io_data *io_data = kiocb->private;
1162 struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1163 int value;
1164
1165 ENTER();
1166
1167 spin_lock_irq(&epfile->ffs->eps_lock);
1168
1169 if (likely(io_data && io_data->ep && io_data->req))
1170 value = usb_ep_dequeue(io_data->ep, io_data->req);
1171 else
1172 value = -EINVAL;
1173
1174 spin_unlock_irq(&epfile->ffs->eps_lock);
1175
1176 return value;
1177}
1178
1179static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1180{
1181 struct ffs_io_data io_data, *p = &io_data;
1182 ssize_t res;
1183
1184 ENTER();
1185
1186 if (!is_sync_kiocb(kiocb)) {
1187 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1188 if (unlikely(!p))
1189 return -ENOMEM;
1190 p->aio = true;
1191 } else {
1192 memset(p, 0, sizeof(*p));
1193 p->aio = false;
1194 }
1195
1196 p->read = false;
1197 p->kiocb = kiocb;
1198 p->data = *from;
1199 p->mm = current->mm;
1200
1201 kiocb->private = p;
1202
1203 if (p->aio)
1204 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1205
1206 res = ffs_epfile_io(kiocb->ki_filp, p);
1207 if (res == -EIOCBQUEUED)
1208 return res;
1209 if (p->aio)
1210 kfree(p);
1211 else
1212 *from = p->data;
1213 return res;
1214}
1215
1216static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1217{
1218 struct ffs_io_data io_data, *p = &io_data;
1219 ssize_t res;
1220
1221 ENTER();
1222
1223 if (!is_sync_kiocb(kiocb)) {
1224 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1225 if (unlikely(!p))
1226 return -ENOMEM;
1227 p->aio = true;
1228 } else {
1229 memset(p, 0, sizeof(*p));
1230 p->aio = false;
1231 }
1232
1233 p->read = true;
1234 p->kiocb = kiocb;
1235 if (p->aio) {
1236 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1237 if (!p->to_free) {
1238 kfree(p);
1239 return -ENOMEM;
1240 }
1241 } else {
1242 p->data = *to;
1243 p->to_free = NULL;
1244 }
1245 p->mm = current->mm;
1246
1247 kiocb->private = p;
1248
1249 if (p->aio)
1250 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1251
1252 res = ffs_epfile_io(kiocb->ki_filp, p);
1253 if (res == -EIOCBQUEUED)
1254 return res;
1255
1256 if (p->aio) {
1257 kfree(p->to_free);
1258 kfree(p);
1259 } else {
1260 *to = p->data;
1261 }
1262 return res;
1263}
1264
1265static int
1266ffs_epfile_release(struct inode *inode, struct file *file)
1267{
1268 struct ffs_epfile *epfile = inode->i_private;
1269
1270 ENTER();
1271
1272 __ffs_epfile_read_buffer_free(epfile);
1273 ffs_data_closed(epfile->ffs);
1274
1275 return 0;
1276}
1277
1278static long ffs_epfile_ioctl(struct file *file, unsigned code,
1279 unsigned long value)
1280{
1281 struct ffs_epfile *epfile = file->private_data;
1282 struct ffs_ep *ep;
1283 int ret;
1284
1285 ENTER();
1286
1287 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1288 return -ENODEV;
1289
1290 /* Wait for endpoint to be enabled */
1291 ep = epfile->ep;
1292 if (!ep) {
1293 if (file->f_flags & O_NONBLOCK)
1294 return -EAGAIN;
1295
1296 ret = wait_event_interruptible(
1297 epfile->ffs->wait, (ep = epfile->ep));
1298 if (ret)
1299 return -EINTR;
1300 }
1301
1302 spin_lock_irq(&epfile->ffs->eps_lock);
1303
1304 /* In the meantime, endpoint got disabled or changed. */
1305 if (epfile->ep != ep) {
1306 spin_unlock_irq(&epfile->ffs->eps_lock);
1307 return -ESHUTDOWN;
1308 }
1309
1310 switch (code) {
1311 case FUNCTIONFS_FIFO_STATUS:
1312 ret = usb_ep_fifo_status(epfile->ep->ep);
1313 break;
1314 case FUNCTIONFS_FIFO_FLUSH:
1315 usb_ep_fifo_flush(epfile->ep->ep);
1316 ret = 0;
1317 break;
1318 case FUNCTIONFS_CLEAR_HALT:
1319 ret = usb_ep_clear_halt(epfile->ep->ep);
1320 break;
1321 case FUNCTIONFS_ENDPOINT_REVMAP:
1322 ret = epfile->ep->num;
1323 break;
1324 case FUNCTIONFS_ENDPOINT_DESC:
1325 {
1326 int desc_idx;
1327 struct usb_endpoint_descriptor *desc;
1328
1329 switch (epfile->ffs->gadget->speed) {
1330 case USB_SPEED_SUPER:
1331 desc_idx = 2;
1332 break;
1333 case USB_SPEED_HIGH:
1334 desc_idx = 1;
1335 break;
1336 default:
1337 desc_idx = 0;
1338 }
1339 desc = epfile->ep->descs[desc_idx];
1340
1341 spin_unlock_irq(&epfile->ffs->eps_lock);
1342 ret = copy_to_user((void __user *)value, desc, desc->bLength);
1343 if (ret)
1344 ret = -EFAULT;
1345 return ret;
1346 }
1347 default:
1348 ret = -ENOTTY;
1349 }
1350 spin_unlock_irq(&epfile->ffs->eps_lock);
1351
1352 return ret;
1353}
1354
1355#ifdef CONFIG_COMPAT
1356static long ffs_epfile_compat_ioctl(struct file *file, unsigned code,
1357 unsigned long value)
1358{
1359 return ffs_epfile_ioctl(file, code, value);
1360}
1361#endif
1362
1363static const struct file_operations ffs_epfile_operations = {
1364 .llseek = no_llseek,
1365
1366 .open = ffs_epfile_open,
1367 .write_iter = ffs_epfile_write_iter,
1368 .read_iter = ffs_epfile_read_iter,
1369 .release = ffs_epfile_release,
1370 .unlocked_ioctl = ffs_epfile_ioctl,
1371#ifdef CONFIG_COMPAT
1372 .compat_ioctl = ffs_epfile_compat_ioctl,
1373#endif
1374};
1375
1376
1377/* File system and super block operations ***********************************/
1378
1379/*
1380 * Mounting the file system creates a controller file, used first for
1381 * function configuration then later for event monitoring.
1382 */
1383
1384static struct inode *__must_check
1385ffs_sb_make_inode(struct super_block *sb, void *data,
1386 const struct file_operations *fops,
1387 const struct inode_operations *iops,
1388 struct ffs_file_perms *perms)
1389{
1390 struct inode *inode;
1391
1392 ENTER();
1393
1394 inode = new_inode(sb);
1395
1396 if (likely(inode)) {
1397 struct timespec64 ts = current_time(inode);
1398
1399 inode->i_ino = get_next_ino();
1400 inode->i_mode = perms->mode;
1401 inode->i_uid = perms->uid;
1402 inode->i_gid = perms->gid;
1403 inode->i_atime = ts;
1404 inode->i_mtime = ts;
1405 inode->i_ctime = ts;
1406 inode->i_private = data;
1407 if (fops)
1408 inode->i_fop = fops;
1409 if (iops)
1410 inode->i_op = iops;
1411 }
1412
1413 return inode;
1414}
1415
1416/* Create "regular" file */
1417static struct dentry *ffs_sb_create_file(struct super_block *sb,
1418 const char *name, void *data,
1419 const struct file_operations *fops)
1420{
1421 struct ffs_data *ffs = sb->s_fs_info;
1422 struct dentry *dentry;
1423 struct inode *inode;
1424
1425 ENTER();
1426
1427 dentry = d_alloc_name(sb->s_root, name);
1428 if (unlikely(!dentry))
1429 return NULL;
1430
1431 inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1432 if (unlikely(!inode)) {
1433 dput(dentry);
1434 return NULL;
1435 }
1436
1437 d_add(dentry, inode);
1438 return dentry;
1439}
1440
1441/* Super block */
1442static const struct super_operations ffs_sb_operations = {
1443 .statfs = simple_statfs,
1444 .drop_inode = generic_delete_inode,
1445};
1446
1447struct ffs_sb_fill_data {
1448 struct ffs_file_perms perms;
1449 umode_t root_mode;
1450 const char *dev_name;
1451 bool no_disconnect;
1452 struct ffs_data *ffs_data;
1453};
1454
1455static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1456{
1457 struct ffs_sb_fill_data *data = fc->fs_private;
1458 struct inode *inode;
1459 struct ffs_data *ffs = data->ffs_data;
1460
1461 ENTER();
1462
1463 ffs->sb = sb;
1464 data->ffs_data = NULL;
1465 sb->s_fs_info = ffs;
1466 sb->s_blocksize = PAGE_SIZE;
1467 sb->s_blocksize_bits = PAGE_SHIFT;
1468 sb->s_magic = FUNCTIONFS_MAGIC;
1469 sb->s_op = &ffs_sb_operations;
1470 sb->s_time_gran = 1;
1471
1472 /* Root inode */
1473 data->perms.mode = data->root_mode;
1474 inode = ffs_sb_make_inode(sb, NULL,
1475 &simple_dir_operations,
1476 &simple_dir_inode_operations,
1477 &data->perms);
1478 sb->s_root = d_make_root(inode);
1479 if (unlikely(!sb->s_root))
1480 return -ENOMEM;
1481
1482 /* EP0 file */
1483 if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1484 &ffs_ep0_operations)))
1485 return -ENOMEM;
1486
1487 return 0;
1488}
1489
1490enum {
1491 Opt_no_disconnect,
1492 Opt_rmode,
1493 Opt_fmode,
1494 Opt_mode,
1495 Opt_uid,
1496 Opt_gid,
1497};
1498
1499static const struct fs_parameter_spec ffs_fs_param_specs[] = {
1500 fsparam_bool ("no_disconnect", Opt_no_disconnect),
1501 fsparam_u32 ("rmode", Opt_rmode),
1502 fsparam_u32 ("fmode", Opt_fmode),
1503 fsparam_u32 ("mode", Opt_mode),
1504 fsparam_u32 ("uid", Opt_uid),
1505 fsparam_u32 ("gid", Opt_gid),
1506 {}
1507};
1508
1509static const struct fs_parameter_description ffs_fs_fs_parameters = {
1510 .name = "kAFS",
1511 .specs = ffs_fs_param_specs,
1512};
1513
1514static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1515{
1516 struct ffs_sb_fill_data *data = fc->fs_private;
1517 struct fs_parse_result result;
1518 int opt;
1519
1520 ENTER();
1521
1522 opt = fs_parse(fc, &ffs_fs_fs_parameters, param, &result);
1523 if (opt < 0)
1524 return opt;
1525
1526 switch (opt) {
1527 case Opt_no_disconnect:
1528 data->no_disconnect = result.boolean;
1529 break;
1530 case Opt_rmode:
1531 data->root_mode = (result.uint_32 & 0555) | S_IFDIR;
1532 break;
1533 case Opt_fmode:
1534 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1535 break;
1536 case Opt_mode:
1537 data->root_mode = (result.uint_32 & 0555) | S_IFDIR;
1538 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1539 break;
1540
1541 case Opt_uid:
1542 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1543 if (!uid_valid(data->perms.uid))
1544 goto unmapped_value;
1545 break;
1546 case Opt_gid:
1547 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1548 if (!gid_valid(data->perms.gid))
1549 goto unmapped_value;
1550 break;
1551
1552 default:
1553 return -ENOPARAM;
1554 }
1555
1556 return 0;
1557
1558unmapped_value:
1559 return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1560}
1561
1562/*
1563 * Set up the superblock for a mount.
1564 */
1565static int ffs_fs_get_tree(struct fs_context *fc)
1566{
1567 struct ffs_sb_fill_data *ctx = fc->fs_private;
1568 void *ffs_dev;
1569 struct ffs_data *ffs;
1570
1571 ENTER();
1572
1573 if (!fc->source)
1574 return invalf(fc, "No source specified");
1575
1576 ffs = ffs_data_new(fc->source);
1577 if (unlikely(!ffs))
1578 return -ENOMEM;
1579 ffs->file_perms = ctx->perms;
1580 ffs->no_disconnect = ctx->no_disconnect;
1581
1582 ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1583 if (unlikely(!ffs->dev_name)) {
1584 ffs_data_put(ffs);
1585 return -ENOMEM;
1586 }
1587
1588 ffs_dev = ffs_acquire_dev(ffs->dev_name);
1589 if (IS_ERR(ffs_dev)) {
1590 ffs_data_put(ffs);
1591 return PTR_ERR(ffs_dev);
1592 }
1593
1594 ffs->private_data = ffs_dev;
1595 ctx->ffs_data = ffs;
1596 return get_tree_nodev(fc, ffs_sb_fill);
1597}
1598
1599static void ffs_fs_free_fc(struct fs_context *fc)
1600{
1601 struct ffs_sb_fill_data *ctx = fc->fs_private;
1602
1603 if (ctx) {
1604 if (ctx->ffs_data) {
1605 ffs_release_dev(ctx->ffs_data);
1606 ffs_data_put(ctx->ffs_data);
1607 }
1608
1609 kfree(ctx);
1610 }
1611}
1612
1613static const struct fs_context_operations ffs_fs_context_ops = {
1614 .free = ffs_fs_free_fc,
1615 .parse_param = ffs_fs_parse_param,
1616 .get_tree = ffs_fs_get_tree,
1617};
1618
1619static int ffs_fs_init_fs_context(struct fs_context *fc)
1620{
1621 struct ffs_sb_fill_data *ctx;
1622
1623 ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1624 if (!ctx)
1625 return -ENOMEM;
1626
1627 ctx->perms.mode = S_IFREG | 0600;
1628 ctx->perms.uid = GLOBAL_ROOT_UID;
1629 ctx->perms.gid = GLOBAL_ROOT_GID;
1630 ctx->root_mode = S_IFDIR | 0500;
1631 ctx->no_disconnect = false;
1632
1633 fc->fs_private = ctx;
1634 fc->ops = &ffs_fs_context_ops;
1635 return 0;
1636}
1637
1638static void
1639ffs_fs_kill_sb(struct super_block *sb)
1640{
1641 ENTER();
1642
1643 kill_litter_super(sb);
1644 if (sb->s_fs_info) {
1645 ffs_release_dev(sb->s_fs_info);
1646 ffs_data_closed(sb->s_fs_info);
1647 }
1648}
1649
1650static struct file_system_type ffs_fs_type = {
1651 .owner = THIS_MODULE,
1652 .name = "functionfs",
1653 .init_fs_context = ffs_fs_init_fs_context,
1654 .parameters = &ffs_fs_fs_parameters,
1655 .kill_sb = ffs_fs_kill_sb,
1656};
1657MODULE_ALIAS_FS("functionfs");
1658
1659
1660/* Driver's main init/cleanup functions *************************************/
1661
1662static int functionfs_init(void)
1663{
1664 int ret;
1665
1666 ENTER();
1667
1668 ret = register_filesystem(&ffs_fs_type);
1669 if (likely(!ret))
1670 pr_info("file system registered\n");
1671 else
1672 pr_err("failed registering file system (%d)\n", ret);
1673
1674 return ret;
1675}
1676
1677static void functionfs_cleanup(void)
1678{
1679 ENTER();
1680
1681 pr_info("unloading\n");
1682 unregister_filesystem(&ffs_fs_type);
1683}
1684
1685
1686/* ffs_data and ffs_function construction and destruction code **************/
1687
1688static void ffs_data_clear(struct ffs_data *ffs);
1689static void ffs_data_reset(struct ffs_data *ffs);
1690
1691static void ffs_data_get(struct ffs_data *ffs)
1692{
1693 ENTER();
1694
1695 refcount_inc(&ffs->ref);
1696}
1697
1698static void ffs_data_opened(struct ffs_data *ffs)
1699{
1700 ENTER();
1701
1702 refcount_inc(&ffs->ref);
1703 if (atomic_add_return(1, &ffs->opened) == 1 &&
1704 ffs->state == FFS_DEACTIVATED) {
1705 ffs->state = FFS_CLOSING;
1706 ffs_data_reset(ffs);
1707 }
1708}
1709
1710static void ffs_data_put(struct ffs_data *ffs)
1711{
1712 ENTER();
1713
1714 if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1715 pr_info("%s(): freeing\n", __func__);
1716 ffs_data_clear(ffs);
1717 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1718 waitqueue_active(&ffs->ep0req_completion.wait) ||
1719 waitqueue_active(&ffs->wait));
1720 destroy_workqueue(ffs->io_completion_wq);
1721 kfree(ffs->dev_name);
1722 kfree(ffs);
1723 }
1724}
1725
1726static void ffs_data_closed(struct ffs_data *ffs)
1727{
1728 ENTER();
1729
1730 if (atomic_dec_and_test(&ffs->opened)) {
1731 if (ffs->no_disconnect) {
1732 ffs->state = FFS_DEACTIVATED;
1733 if (ffs->epfiles) {
1734 ffs_epfiles_destroy(ffs->epfiles,
1735 ffs->eps_count);
1736 ffs->epfiles = NULL;
1737 }
1738 if (ffs->setup_state == FFS_SETUP_PENDING)
1739 __ffs_ep0_stall(ffs);
1740 } else {
1741 ffs->state = FFS_CLOSING;
1742 ffs_data_reset(ffs);
1743 }
1744 }
1745 if (atomic_read(&ffs->opened) < 0) {
1746 ffs->state = FFS_CLOSING;
1747 ffs_data_reset(ffs);
1748 }
1749
1750 ffs_data_put(ffs);
1751}
1752
1753static struct ffs_data *ffs_data_new(const char *dev_name)
1754{
1755 struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1756 if (unlikely(!ffs))
1757 return NULL;
1758
1759 ENTER();
1760
1761 ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1762 if (!ffs->io_completion_wq) {
1763 kfree(ffs);
1764 return NULL;
1765 }
1766
1767 refcount_set(&ffs->ref, 1);
1768 atomic_set(&ffs->opened, 0);
1769 ffs->state = FFS_READ_DESCRIPTORS;
1770 mutex_init(&ffs->mutex);
1771 spin_lock_init(&ffs->eps_lock);
1772 init_waitqueue_head(&ffs->ev.waitq);
1773 init_waitqueue_head(&ffs->wait);
1774 init_completion(&ffs->ep0req_completion);
1775
1776 /* XXX REVISIT need to update it in some places, or do we? */
1777 ffs->ev.can_stall = 1;
1778
1779 return ffs;
1780}
1781
1782static void ffs_data_clear(struct ffs_data *ffs)
1783{
1784 ENTER();
1785
1786 ffs_closed(ffs);
1787
1788 BUG_ON(ffs->gadget);
1789
1790 if (ffs->epfiles)
1791 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1792
1793 if (ffs->ffs_eventfd)
1794 eventfd_ctx_put(ffs->ffs_eventfd);
1795
1796 kfree(ffs->raw_descs_data);
1797 kfree(ffs->raw_strings);
1798 kfree(ffs->stringtabs);
1799}
1800
1801static void ffs_data_reset(struct ffs_data *ffs)
1802{
1803 ENTER();
1804
1805 ffs_data_clear(ffs);
1806
1807 ffs->epfiles = NULL;
1808 ffs->raw_descs_data = NULL;
1809 ffs->raw_descs = NULL;
1810 ffs->raw_strings = NULL;
1811 ffs->stringtabs = NULL;
1812
1813 ffs->raw_descs_length = 0;
1814 ffs->fs_descs_count = 0;
1815 ffs->hs_descs_count = 0;
1816 ffs->ss_descs_count = 0;
1817
1818 ffs->strings_count = 0;
1819 ffs->interfaces_count = 0;
1820 ffs->eps_count = 0;
1821
1822 ffs->ev.count = 0;
1823
1824 ffs->state = FFS_READ_DESCRIPTORS;
1825 ffs->setup_state = FFS_NO_SETUP;
1826 ffs->flags = 0;
1827}
1828
1829
1830static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1831{
1832 struct usb_gadget_strings **lang;
1833 int first_id;
1834
1835 ENTER();
1836
1837 if (WARN_ON(ffs->state != FFS_ACTIVE
1838 || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1839 return -EBADFD;
1840
1841 first_id = usb_string_ids_n(cdev, ffs->strings_count);
1842 if (unlikely(first_id < 0))
1843 return first_id;
1844
1845 ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1846 if (unlikely(!ffs->ep0req))
1847 return -ENOMEM;
1848 ffs->ep0req->complete = ffs_ep0_complete;
1849 ffs->ep0req->context = ffs;
1850
1851 lang = ffs->stringtabs;
1852 if (lang) {
1853 for (; *lang; ++lang) {
1854 struct usb_string *str = (*lang)->strings;
1855 int id = first_id;
1856 for (; str->s; ++id, ++str)
1857 str->id = id;
1858 }
1859 }
1860
1861 ffs->gadget = cdev->gadget;
1862 ffs_data_get(ffs);
1863 return 0;
1864}
1865
1866static void functionfs_unbind(struct ffs_data *ffs)
1867{
1868 ENTER();
1869
1870 if (!WARN_ON(!ffs->gadget)) {
1871 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1872 ffs->ep0req = NULL;
1873 ffs->gadget = NULL;
1874 clear_bit(FFS_FL_BOUND, &ffs->flags);
1875 ffs_data_put(ffs);
1876 }
1877}
1878
1879static int ffs_epfiles_create(struct ffs_data *ffs)
1880{
1881 struct ffs_epfile *epfile, *epfiles;
1882 unsigned i, count;
1883
1884 ENTER();
1885
1886 count = ffs->eps_count;
1887 epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1888 if (!epfiles)
1889 return -ENOMEM;
1890
1891 epfile = epfiles;
1892 for (i = 1; i <= count; ++i, ++epfile) {
1893 epfile->ffs = ffs;
1894 mutex_init(&epfile->mutex);
1895 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1896 sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1897 else
1898 sprintf(epfile->name, "ep%u", i);
1899 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1900 epfile,
1901 &ffs_epfile_operations);
1902 if (unlikely(!epfile->dentry)) {
1903 ffs_epfiles_destroy(epfiles, i - 1);
1904 return -ENOMEM;
1905 }
1906 }
1907
1908 ffs->epfiles = epfiles;
1909 return 0;
1910}
1911
1912static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1913{
1914 struct ffs_epfile *epfile = epfiles;
1915
1916 ENTER();
1917
1918 for (; count; --count, ++epfile) {
1919 BUG_ON(mutex_is_locked(&epfile->mutex));
1920 if (epfile->dentry) {
1921 d_delete(epfile->dentry);
1922 dput(epfile->dentry);
1923 epfile->dentry = NULL;
1924 }
1925 }
1926
1927 kfree(epfiles);
1928}
1929
1930static void ffs_func_eps_disable(struct ffs_function *func)
1931{
1932 struct ffs_ep *ep = func->eps;
1933 struct ffs_epfile *epfile = func->ffs->epfiles;
1934 unsigned count = func->ffs->eps_count;
1935 unsigned long flags;
1936
1937 spin_lock_irqsave(&func->ffs->eps_lock, flags);
1938 while (count--) {
1939 /* pending requests get nuked */
1940 if (likely(ep->ep))
1941 usb_ep_disable(ep->ep);
1942 ++ep;
1943
1944 if (epfile) {
1945 epfile->ep = NULL;
1946 __ffs_epfile_read_buffer_free(epfile);
1947 ++epfile;
1948 }
1949 }
1950 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1951}
1952
1953static int ffs_func_eps_enable(struct ffs_function *func)
1954{
1955 struct ffs_data *ffs = func->ffs;
1956 struct ffs_ep *ep = func->eps;
1957 struct ffs_epfile *epfile = ffs->epfiles;
1958 unsigned count = ffs->eps_count;
1959 unsigned long flags;
1960 int ret = 0;
1961
1962 spin_lock_irqsave(&func->ffs->eps_lock, flags);
1963 while(count--) {
1964 ep->ep->driver_data = ep;
1965
1966 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1967 if (ret) {
1968 pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1969 __func__, ep->ep->name, ret);
1970 break;
1971 }
1972
1973 ret = usb_ep_enable(ep->ep);
1974 if (likely(!ret)) {
1975 epfile->ep = ep;
1976 epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1977 epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1978 } else {
1979 break;
1980 }
1981
1982 ++ep;
1983 ++epfile;
1984 }
1985
1986 wake_up_interruptible(&ffs->wait);
1987 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1988
1989 return ret;
1990}
1991
1992
1993/* Parsing and building descriptors and strings *****************************/
1994
1995/*
1996 * This validates if data pointed by data is a valid USB descriptor as
1997 * well as record how many interfaces, endpoints and strings are
1998 * required by given configuration. Returns address after the
1999 * descriptor or NULL if data is invalid.
2000 */
2001
2002enum ffs_entity_type {
2003 FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
2004};
2005
2006enum ffs_os_desc_type {
2007 FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
2008};
2009
2010typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2011 u8 *valuep,
2012 struct usb_descriptor_header *desc,
2013 void *priv);
2014
2015typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2016 struct usb_os_desc_header *h, void *data,
2017 unsigned len, void *priv);
2018
2019static int __must_check ffs_do_single_desc(char *data, unsigned len,
2020 ffs_entity_callback entity,
2021 void *priv, int *current_class)
2022{
2023 struct usb_descriptor_header *_ds = (void *)data;
2024 u8 length;
2025 int ret;
2026
2027 ENTER();
2028
2029 /* At least two bytes are required: length and type */
2030 if (len < 2) {
2031 pr_vdebug("descriptor too short\n");
2032 return -EINVAL;
2033 }
2034
2035 /* If we have at least as many bytes as the descriptor takes? */
2036 length = _ds->bLength;
2037 if (len < length) {
2038 pr_vdebug("descriptor longer then available data\n");
2039 return -EINVAL;
2040 }
2041
2042#define __entity_check_INTERFACE(val) 1
2043#define __entity_check_STRING(val) (val)
2044#define __entity_check_ENDPOINT(val) ((val) & USB_ENDPOINT_NUMBER_MASK)
2045#define __entity(type, val) do { \
2046 pr_vdebug("entity " #type "(%02x)\n", (val)); \
2047 if (unlikely(!__entity_check_ ##type(val))) { \
2048 pr_vdebug("invalid entity's value\n"); \
2049 return -EINVAL; \
2050 } \
2051 ret = entity(FFS_ ##type, &val, _ds, priv); \
2052 if (unlikely(ret < 0)) { \
2053 pr_debug("entity " #type "(%02x); ret = %d\n", \
2054 (val), ret); \
2055 return ret; \
2056 } \
2057 } while (0)
2058
2059 /* Parse descriptor depending on type. */
2060 switch (_ds->bDescriptorType) {
2061 case USB_DT_DEVICE:
2062 case USB_DT_CONFIG:
2063 case USB_DT_STRING:
2064 case USB_DT_DEVICE_QUALIFIER:
2065 /* function can't have any of those */
2066 pr_vdebug("descriptor reserved for gadget: %d\n",
2067 _ds->bDescriptorType);
2068 return -EINVAL;
2069
2070 case USB_DT_INTERFACE: {
2071 struct usb_interface_descriptor *ds = (void *)_ds;
2072 pr_vdebug("interface descriptor\n");
2073 if (length != sizeof *ds)
2074 goto inv_length;
2075
2076 __entity(INTERFACE, ds->bInterfaceNumber);
2077 if (ds->iInterface)
2078 __entity(STRING, ds->iInterface);
2079 *current_class = ds->bInterfaceClass;
2080 }
2081 break;
2082
2083 case USB_DT_ENDPOINT: {
2084 struct usb_endpoint_descriptor *ds = (void *)_ds;
2085 pr_vdebug("endpoint descriptor\n");
2086 if (length != USB_DT_ENDPOINT_SIZE &&
2087 length != USB_DT_ENDPOINT_AUDIO_SIZE)
2088 goto inv_length;
2089 __entity(ENDPOINT, ds->bEndpointAddress);
2090 }
2091 break;
2092
2093 case USB_TYPE_CLASS | 0x01:
2094 if (*current_class == USB_INTERFACE_CLASS_HID) {
2095 pr_vdebug("hid descriptor\n");
2096 if (length != sizeof(struct hid_descriptor))
2097 goto inv_length;
2098 break;
2099 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2100 pr_vdebug("ccid descriptor\n");
2101 if (length != sizeof(struct ccid_descriptor))
2102 goto inv_length;
2103 break;
2104 } else {
2105 pr_vdebug("unknown descriptor: %d for class %d\n",
2106 _ds->bDescriptorType, *current_class);
2107 return -EINVAL;
2108 }
2109
2110 case USB_DT_OTG:
2111 if (length != sizeof(struct usb_otg_descriptor))
2112 goto inv_length;
2113 break;
2114
2115 case USB_DT_INTERFACE_ASSOCIATION: {
2116 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2117 pr_vdebug("interface association descriptor\n");
2118 if (length != sizeof *ds)
2119 goto inv_length;
2120 if (ds->iFunction)
2121 __entity(STRING, ds->iFunction);
2122 }
2123 break;
2124
2125 case USB_DT_SS_ENDPOINT_COMP:
2126 pr_vdebug("EP SS companion descriptor\n");
2127 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2128 goto inv_length;
2129 break;
2130
2131 case USB_DT_OTHER_SPEED_CONFIG:
2132 case USB_DT_INTERFACE_POWER:
2133 case USB_DT_DEBUG:
2134 case USB_DT_SECURITY:
2135 case USB_DT_CS_RADIO_CONTROL:
2136 /* TODO */
2137 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2138 return -EINVAL;
2139
2140 default:
2141 /* We should never be here */
2142 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2143 return -EINVAL;
2144
2145inv_length:
2146 pr_vdebug("invalid length: %d (descriptor %d)\n",
2147 _ds->bLength, _ds->bDescriptorType);
2148 return -EINVAL;
2149 }
2150
2151#undef __entity
2152#undef __entity_check_DESCRIPTOR
2153#undef __entity_check_INTERFACE
2154#undef __entity_check_STRING
2155#undef __entity_check_ENDPOINT
2156
2157 return length;
2158}
2159
2160static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2161 ffs_entity_callback entity, void *priv)
2162{
2163 const unsigned _len = len;
2164 unsigned long num = 0;
2165 int current_class = -1;
2166
2167 ENTER();
2168
2169 for (;;) {
2170 int ret;
2171
2172 if (num == count)
2173 data = NULL;
2174
2175 /* Record "descriptor" entity */
2176 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2177 if (unlikely(ret < 0)) {
2178 pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2179 num, ret);
2180 return ret;
2181 }
2182
2183 if (!data)
2184 return _len - len;
2185
2186 ret = ffs_do_single_desc(data, len, entity, priv,
2187 ¤t_class);
2188 if (unlikely(ret < 0)) {
2189 pr_debug("%s returns %d\n", __func__, ret);
2190 return ret;
2191 }
2192
2193 len -= ret;
2194 data += ret;
2195 ++num;
2196 }
2197}
2198
2199static int __ffs_data_do_entity(enum ffs_entity_type type,
2200 u8 *valuep, struct usb_descriptor_header *desc,
2201 void *priv)
2202{
2203 struct ffs_desc_helper *helper = priv;
2204 struct usb_endpoint_descriptor *d;
2205
2206 ENTER();
2207
2208 switch (type) {
2209 case FFS_DESCRIPTOR:
2210 break;
2211
2212 case FFS_INTERFACE:
2213 /*
2214 * Interfaces are indexed from zero so if we
2215 * encountered interface "n" then there are at least
2216 * "n+1" interfaces.
2217 */
2218 if (*valuep >= helper->interfaces_count)
2219 helper->interfaces_count = *valuep + 1;
2220 break;
2221
2222 case FFS_STRING:
2223 /*
2224 * Strings are indexed from 1 (0 is reserved
2225 * for languages list)
2226 */
2227 if (*valuep > helper->ffs->strings_count)
2228 helper->ffs->strings_count = *valuep;
2229 break;
2230
2231 case FFS_ENDPOINT:
2232 d = (void *)desc;
2233 helper->eps_count++;
2234 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2235 return -EINVAL;
2236 /* Check if descriptors for any speed were already parsed */
2237 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2238 helper->ffs->eps_addrmap[helper->eps_count] =
2239 d->bEndpointAddress;
2240 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2241 d->bEndpointAddress)
2242 return -EINVAL;
2243 break;
2244 }
2245
2246 return 0;
2247}
2248
2249static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2250 struct usb_os_desc_header *desc)
2251{
2252 u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2253 u16 w_index = le16_to_cpu(desc->wIndex);
2254
2255 if (bcd_version != 1) {
2256 pr_vdebug("unsupported os descriptors version: %d",
2257 bcd_version);
2258 return -EINVAL;
2259 }
2260 switch (w_index) {
2261 case 0x4:
2262 *next_type = FFS_OS_DESC_EXT_COMPAT;
2263 break;
2264 case 0x5:
2265 *next_type = FFS_OS_DESC_EXT_PROP;
2266 break;
2267 default:
2268 pr_vdebug("unsupported os descriptor type: %d", w_index);
2269 return -EINVAL;
2270 }
2271
2272 return sizeof(*desc);
2273}
2274
2275/*
2276 * Process all extended compatibility/extended property descriptors
2277 * of a feature descriptor
2278 */
2279static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2280 enum ffs_os_desc_type type,
2281 u16 feature_count,
2282 ffs_os_desc_callback entity,
2283 void *priv,
2284 struct usb_os_desc_header *h)
2285{
2286 int ret;
2287 const unsigned _len = len;
2288
2289 ENTER();
2290
2291 /* loop over all ext compat/ext prop descriptors */
2292 while (feature_count--) {
2293 ret = entity(type, h, data, len, priv);
2294 if (unlikely(ret < 0)) {
2295 pr_debug("bad OS descriptor, type: %d\n", type);
2296 return ret;
2297 }
2298 data += ret;
2299 len -= ret;
2300 }
2301 return _len - len;
2302}
2303
2304/* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2305static int __must_check ffs_do_os_descs(unsigned count,
2306 char *data, unsigned len,
2307 ffs_os_desc_callback entity, void *priv)
2308{
2309 const unsigned _len = len;
2310 unsigned long num = 0;
2311
2312 ENTER();
2313
2314 for (num = 0; num < count; ++num) {
2315 int ret;
2316 enum ffs_os_desc_type type;
2317 u16 feature_count;
2318 struct usb_os_desc_header *desc = (void *)data;
2319
2320 if (len < sizeof(*desc))
2321 return -EINVAL;
2322
2323 /*
2324 * Record "descriptor" entity.
2325 * Process dwLength, bcdVersion, wIndex, get b/wCount.
2326 * Move the data pointer to the beginning of extended
2327 * compatibilities proper or extended properties proper
2328 * portions of the data
2329 */
2330 if (le32_to_cpu(desc->dwLength) > len)
2331 return -EINVAL;
2332
2333 ret = __ffs_do_os_desc_header(&type, desc);
2334 if (unlikely(ret < 0)) {
2335 pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2336 num, ret);
2337 return ret;
2338 }
2339 /*
2340 * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2341 */
2342 feature_count = le16_to_cpu(desc->wCount);
2343 if (type == FFS_OS_DESC_EXT_COMPAT &&
2344 (feature_count > 255 || desc->Reserved))
2345 return -EINVAL;
2346 len -= ret;
2347 data += ret;
2348
2349 /*
2350 * Process all function/property descriptors
2351 * of this Feature Descriptor
2352 */
2353 ret = ffs_do_single_os_desc(data, len, type,
2354 feature_count, entity, priv, desc);
2355 if (unlikely(ret < 0)) {
2356 pr_debug("%s returns %d\n", __func__, ret);
2357 return ret;
2358 }
2359
2360 len -= ret;
2361 data += ret;
2362 }
2363 return _len - len;
2364}
2365
2366/**
2367 * Validate contents of the buffer from userspace related to OS descriptors.
2368 */
2369static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2370 struct usb_os_desc_header *h, void *data,
2371 unsigned len, void *priv)
2372{
2373 struct ffs_data *ffs = priv;
2374 u8 length;
2375
2376 ENTER();
2377
2378 switch (type) {
2379 case FFS_OS_DESC_EXT_COMPAT: {
2380 struct usb_ext_compat_desc *d = data;
2381 int i;
2382
2383 if (len < sizeof(*d) ||
2384 d->bFirstInterfaceNumber >= ffs->interfaces_count)
2385 return -EINVAL;
2386 if (d->Reserved1 != 1) {
2387 /*
2388 * According to the spec, Reserved1 must be set to 1
2389 * but older kernels incorrectly rejected non-zero
2390 * values. We fix it here to avoid returning EINVAL
2391 * in response to values we used to accept.
2392 */
2393 pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2394 d->Reserved1 = 1;
2395 }
2396 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2397 if (d->Reserved2[i])
2398 return -EINVAL;
2399
2400 length = sizeof(struct usb_ext_compat_desc);
2401 }
2402 break;
2403 case FFS_OS_DESC_EXT_PROP: {
2404 struct usb_ext_prop_desc *d = data;
2405 u32 type, pdl;
2406 u16 pnl;
2407
2408 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2409 return -EINVAL;
2410 length = le32_to_cpu(d->dwSize);
2411 if (len < length)
2412 return -EINVAL;
2413 type = le32_to_cpu(d->dwPropertyDataType);
2414 if (type < USB_EXT_PROP_UNICODE ||
2415 type > USB_EXT_PROP_UNICODE_MULTI) {
2416 pr_vdebug("unsupported os descriptor property type: %d",
2417 type);
2418 return -EINVAL;
2419 }
2420 pnl = le16_to_cpu(d->wPropertyNameLength);
2421 if (length < 14 + pnl) {
2422 pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2423 length, pnl, type);
2424 return -EINVAL;
2425 }
2426 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2427 if (length != 14 + pnl + pdl) {
2428 pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2429 length, pnl, pdl, type);
2430 return -EINVAL;
2431 }
2432 ++ffs->ms_os_descs_ext_prop_count;
2433 /* property name reported to the host as "WCHAR"s */
2434 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2435 ffs->ms_os_descs_ext_prop_data_len += pdl;
2436 }
2437 break;
2438 default:
2439 pr_vdebug("unknown descriptor: %d\n", type);
2440 return -EINVAL;
2441 }
2442 return length;
2443}
2444
2445static int __ffs_data_got_descs(struct ffs_data *ffs,
2446 char *const _data, size_t len)
2447{
2448 char *data = _data, *raw_descs;
2449 unsigned os_descs_count = 0, counts[3], flags;
2450 int ret = -EINVAL, i;
2451 struct ffs_desc_helper helper;
2452
2453 ENTER();
2454
2455 if (get_unaligned_le32(data + 4) != len)
2456 goto error;
2457
2458 switch (get_unaligned_le32(data)) {
2459 case FUNCTIONFS_DESCRIPTORS_MAGIC:
2460 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2461 data += 8;
2462 len -= 8;
2463 break;
2464 case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2465 flags = get_unaligned_le32(data + 8);
2466 ffs->user_flags = flags;
2467 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2468 FUNCTIONFS_HAS_HS_DESC |
2469 FUNCTIONFS_HAS_SS_DESC |
2470 FUNCTIONFS_HAS_MS_OS_DESC |
2471 FUNCTIONFS_VIRTUAL_ADDR |
2472 FUNCTIONFS_EVENTFD |
2473 FUNCTIONFS_ALL_CTRL_RECIP |
2474 FUNCTIONFS_CONFIG0_SETUP)) {
2475 ret = -ENOSYS;
2476 goto error;
2477 }
2478 data += 12;
2479 len -= 12;
2480 break;
2481 default:
2482 goto error;
2483 }
2484
2485 if (flags & FUNCTIONFS_EVENTFD) {
2486 if (len < 4)
2487 goto error;
2488 ffs->ffs_eventfd =
2489 eventfd_ctx_fdget((int)get_unaligned_le32(data));
2490 if (IS_ERR(ffs->ffs_eventfd)) {
2491 ret = PTR_ERR(ffs->ffs_eventfd);
2492 ffs->ffs_eventfd = NULL;
2493 goto error;
2494 }
2495 data += 4;
2496 len -= 4;
2497 }
2498
2499 /* Read fs_count, hs_count and ss_count (if present) */
2500 for (i = 0; i < 3; ++i) {
2501 if (!(flags & (1 << i))) {
2502 counts[i] = 0;
2503 } else if (len < 4) {
2504 goto error;
2505 } else {
2506 counts[i] = get_unaligned_le32(data);
2507 data += 4;
2508 len -= 4;
2509 }
2510 }
2511 if (flags & (1 << i)) {
2512 if (len < 4) {
2513 goto error;
2514 }
2515 os_descs_count = get_unaligned_le32(data);
2516 data += 4;
2517 len -= 4;
2518 };
2519
2520 /* Read descriptors */
2521 raw_descs = data;
2522 helper.ffs = ffs;
2523 for (i = 0; i < 3; ++i) {
2524 if (!counts[i])
2525 continue;
2526 helper.interfaces_count = 0;
2527 helper.eps_count = 0;
2528 ret = ffs_do_descs(counts[i], data, len,
2529 __ffs_data_do_entity, &helper);
2530 if (ret < 0)
2531 goto error;
2532 if (!ffs->eps_count && !ffs->interfaces_count) {
2533 ffs->eps_count = helper.eps_count;
2534 ffs->interfaces_count = helper.interfaces_count;
2535 } else {
2536 if (ffs->eps_count != helper.eps_count) {
2537 ret = -EINVAL;
2538 goto error;
2539 }
2540 if (ffs->interfaces_count != helper.interfaces_count) {
2541 ret = -EINVAL;
2542 goto error;
2543 }
2544 }
2545 data += ret;
2546 len -= ret;
2547 }
2548 if (os_descs_count) {
2549 ret = ffs_do_os_descs(os_descs_count, data, len,
2550 __ffs_data_do_os_desc, ffs);
2551 if (ret < 0)
2552 goto error;
2553 data += ret;
2554 len -= ret;
2555 }
2556
2557 if (raw_descs == data || len) {
2558 ret = -EINVAL;
2559 goto error;
2560 }
2561
2562 ffs->raw_descs_data = _data;
2563 ffs->raw_descs = raw_descs;
2564 ffs->raw_descs_length = data - raw_descs;
2565 ffs->fs_descs_count = counts[0];
2566 ffs->hs_descs_count = counts[1];
2567 ffs->ss_descs_count = counts[2];
2568 ffs->ms_os_descs_count = os_descs_count;
2569
2570 return 0;
2571
2572error:
2573 kfree(_data);
2574 return ret;
2575}
2576
2577static int __ffs_data_got_strings(struct ffs_data *ffs,
2578 char *const _data, size_t len)
2579{
2580 u32 str_count, needed_count, lang_count;
2581 struct usb_gadget_strings **stringtabs, *t;
2582 const char *data = _data;
2583 struct usb_string *s;
2584
2585 ENTER();
2586
2587 if (unlikely(len < 16 ||
2588 get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2589 get_unaligned_le32(data + 4) != len))
2590 goto error;
2591 str_count = get_unaligned_le32(data + 8);
2592 lang_count = get_unaligned_le32(data + 12);
2593
2594 /* if one is zero the other must be zero */
2595 if (unlikely(!str_count != !lang_count))
2596 goto error;
2597
2598 /* Do we have at least as many strings as descriptors need? */
2599 needed_count = ffs->strings_count;
2600 if (unlikely(str_count < needed_count))
2601 goto error;
2602
2603 /*
2604 * If we don't need any strings just return and free all
2605 * memory.
2606 */
2607 if (!needed_count) {
2608 kfree(_data);
2609 return 0;
2610 }
2611
2612 /* Allocate everything in one chunk so there's less maintenance. */
2613 {
2614 unsigned i = 0;
2615 vla_group(d);
2616 vla_item(d, struct usb_gadget_strings *, stringtabs,
2617 lang_count + 1);
2618 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2619 vla_item(d, struct usb_string, strings,
2620 lang_count*(needed_count+1));
2621
2622 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2623
2624 if (unlikely(!vlabuf)) {
2625 kfree(_data);
2626 return -ENOMEM;
2627 }
2628
2629 /* Initialize the VLA pointers */
2630 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2631 t = vla_ptr(vlabuf, d, stringtab);
2632 i = lang_count;
2633 do {
2634 *stringtabs++ = t++;
2635 } while (--i);
2636 *stringtabs = NULL;
2637
2638 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2639 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2640 t = vla_ptr(vlabuf, d, stringtab);
2641 s = vla_ptr(vlabuf, d, strings);
2642 }
2643
2644 /* For each language */
2645 data += 16;
2646 len -= 16;
2647
2648 do { /* lang_count > 0 so we can use do-while */
2649 unsigned needed = needed_count;
2650
2651 if (unlikely(len < 3))
2652 goto error_free;
2653 t->language = get_unaligned_le16(data);
2654 t->strings = s;
2655 ++t;
2656
2657 data += 2;
2658 len -= 2;
2659
2660 /* For each string */
2661 do { /* str_count > 0 so we can use do-while */
2662 size_t length = strnlen(data, len);
2663
2664 if (unlikely(length == len))
2665 goto error_free;
2666
2667 /*
2668 * User may provide more strings then we need,
2669 * if that's the case we simply ignore the
2670 * rest
2671 */
2672 if (likely(needed)) {
2673 /*
2674 * s->id will be set while adding
2675 * function to configuration so for
2676 * now just leave garbage here.
2677 */
2678 s->s = data;
2679 --needed;
2680 ++s;
2681 }
2682
2683 data += length + 1;
2684 len -= length + 1;
2685 } while (--str_count);
2686
2687 s->id = 0; /* terminator */
2688 s->s = NULL;
2689 ++s;
2690
2691 } while (--lang_count);
2692
2693 /* Some garbage left? */
2694 if (unlikely(len))
2695 goto error_free;
2696
2697 /* Done! */
2698 ffs->stringtabs = stringtabs;
2699 ffs->raw_strings = _data;
2700
2701 return 0;
2702
2703error_free:
2704 kfree(stringtabs);
2705error:
2706 kfree(_data);
2707 return -EINVAL;
2708}
2709
2710
2711/* Events handling and management *******************************************/
2712
2713static void __ffs_event_add(struct ffs_data *ffs,
2714 enum usb_functionfs_event_type type)
2715{
2716 enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2717 int neg = 0;
2718
2719 /*
2720 * Abort any unhandled setup
2721 *
2722 * We do not need to worry about some cmpxchg() changing value
2723 * of ffs->setup_state without holding the lock because when
2724 * state is FFS_SETUP_PENDING cmpxchg() in several places in
2725 * the source does nothing.
2726 */
2727 if (ffs->setup_state == FFS_SETUP_PENDING)
2728 ffs->setup_state = FFS_SETUP_CANCELLED;
2729
2730 /*
2731 * Logic of this function guarantees that there are at most four pending
2732 * evens on ffs->ev.types queue. This is important because the queue
2733 * has space for four elements only and __ffs_ep0_read_events function
2734 * depends on that limit as well. If more event types are added, those
2735 * limits have to be revisited or guaranteed to still hold.
2736 */
2737 switch (type) {
2738 case FUNCTIONFS_RESUME:
2739 rem_type2 = FUNCTIONFS_SUSPEND;
2740 /* FALL THROUGH */
2741 case FUNCTIONFS_SUSPEND:
2742 case FUNCTIONFS_SETUP:
2743 rem_type1 = type;
2744 /* Discard all similar events */
2745 break;
2746
2747 case FUNCTIONFS_BIND:
2748 case FUNCTIONFS_UNBIND:
2749 case FUNCTIONFS_DISABLE:
2750 case FUNCTIONFS_ENABLE:
2751 /* Discard everything other then power management. */
2752 rem_type1 = FUNCTIONFS_SUSPEND;
2753 rem_type2 = FUNCTIONFS_RESUME;
2754 neg = 1;
2755 break;
2756
2757 default:
2758 WARN(1, "%d: unknown event, this should not happen\n", type);
2759 return;
2760 }
2761
2762 {
2763 u8 *ev = ffs->ev.types, *out = ev;
2764 unsigned n = ffs->ev.count;
2765 for (; n; --n, ++ev)
2766 if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2767 *out++ = *ev;
2768 else
2769 pr_vdebug("purging event %d\n", *ev);
2770 ffs->ev.count = out - ffs->ev.types;
2771 }
2772
2773 pr_vdebug("adding event %d\n", type);
2774 ffs->ev.types[ffs->ev.count++] = type;
2775 wake_up_locked(&ffs->ev.waitq);
2776 if (ffs->ffs_eventfd)
2777 eventfd_signal(ffs->ffs_eventfd, 1);
2778}
2779
2780static void ffs_event_add(struct ffs_data *ffs,
2781 enum usb_functionfs_event_type type)
2782{
2783 unsigned long flags;
2784 spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2785 __ffs_event_add(ffs, type);
2786 spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2787}
2788
2789/* Bind/unbind USB function hooks *******************************************/
2790
2791static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2792{
2793 int i;
2794
2795 for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2796 if (ffs->eps_addrmap[i] == endpoint_address)
2797 return i;
2798 return -ENOENT;
2799}
2800
2801static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2802 struct usb_descriptor_header *desc,
2803 void *priv)
2804{
2805 struct usb_endpoint_descriptor *ds = (void *)desc;
2806 struct ffs_function *func = priv;
2807 struct ffs_ep *ffs_ep;
2808 unsigned ep_desc_id;
2809 int idx;
2810 static const char *speed_names[] = { "full", "high", "super" };
2811
2812 if (type != FFS_DESCRIPTOR)
2813 return 0;
2814
2815 /*
2816 * If ss_descriptors is not NULL, we are reading super speed
2817 * descriptors; if hs_descriptors is not NULL, we are reading high
2818 * speed descriptors; otherwise, we are reading full speed
2819 * descriptors.
2820 */
2821 if (func->function.ss_descriptors) {
2822 ep_desc_id = 2;
2823 func->function.ss_descriptors[(long)valuep] = desc;
2824 } else if (func->function.hs_descriptors) {
2825 ep_desc_id = 1;
2826 func->function.hs_descriptors[(long)valuep] = desc;
2827 } else {
2828 ep_desc_id = 0;
2829 func->function.fs_descriptors[(long)valuep] = desc;
2830 }
2831
2832 if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2833 return 0;
2834
2835 idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2836 if (idx < 0)
2837 return idx;
2838
2839 ffs_ep = func->eps + idx;
2840
2841 if (unlikely(ffs_ep->descs[ep_desc_id])) {
2842 pr_err("two %sspeed descriptors for EP %d\n",
2843 speed_names[ep_desc_id],
2844 ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2845 return -EINVAL;
2846 }
2847 ffs_ep->descs[ep_desc_id] = ds;
2848
2849 ffs_dump_mem(": Original ep desc", ds, ds->bLength);
2850 if (ffs_ep->ep) {
2851 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2852 if (!ds->wMaxPacketSize)
2853 ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2854 } else {
2855 struct usb_request *req;
2856 struct usb_ep *ep;
2857 u8 bEndpointAddress;
2858 u16 wMaxPacketSize;
2859
2860 /*
2861 * We back up bEndpointAddress because autoconfig overwrites
2862 * it with physical endpoint address.
2863 */
2864 bEndpointAddress = ds->bEndpointAddress;
2865 /*
2866 * We back up wMaxPacketSize because autoconfig treats
2867 * endpoint descriptors as if they were full speed.
2868 */
2869 wMaxPacketSize = ds->wMaxPacketSize;
2870 pr_vdebug("autoconfig\n");
2871 ep = usb_ep_autoconfig(func->gadget, ds);
2872 if (unlikely(!ep))
2873 return -ENOTSUPP;
2874 ep->driver_data = func->eps + idx;
2875
2876 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2877 if (unlikely(!req))
2878 return -ENOMEM;
2879
2880 ffs_ep->ep = ep;
2881 ffs_ep->req = req;
2882 func->eps_revmap[ds->bEndpointAddress &
2883 USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2884 /*
2885 * If we use virtual address mapping, we restore
2886 * original bEndpointAddress value.
2887 */
2888 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2889 ds->bEndpointAddress = bEndpointAddress;
2890 /*
2891 * Restore wMaxPacketSize which was potentially
2892 * overwritten by autoconfig.
2893 */
2894 ds->wMaxPacketSize = wMaxPacketSize;
2895 }
2896 ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2897
2898 return 0;
2899}
2900
2901static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2902 struct usb_descriptor_header *desc,
2903 void *priv)
2904{
2905 struct ffs_function *func = priv;
2906 unsigned idx;
2907 u8 newValue;
2908
2909 switch (type) {
2910 default:
2911 case FFS_DESCRIPTOR:
2912 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2913 return 0;
2914
2915 case FFS_INTERFACE:
2916 idx = *valuep;
2917 if (func->interfaces_nums[idx] < 0) {
2918 int id = usb_interface_id(func->conf, &func->function);
2919 if (unlikely(id < 0))
2920 return id;
2921 func->interfaces_nums[idx] = id;
2922 }
2923 newValue = func->interfaces_nums[idx];
2924 break;
2925
2926 case FFS_STRING:
2927 /* String' IDs are allocated when fsf_data is bound to cdev */
2928 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2929 break;
2930
2931 case FFS_ENDPOINT:
2932 /*
2933 * USB_DT_ENDPOINT are handled in
2934 * __ffs_func_bind_do_descs().
2935 */
2936 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2937 return 0;
2938
2939 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2940 if (unlikely(!func->eps[idx].ep))
2941 return -EINVAL;
2942
2943 {
2944 struct usb_endpoint_descriptor **descs;
2945 descs = func->eps[idx].descs;
2946 newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2947 }
2948 break;
2949 }
2950
2951 pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2952 *valuep = newValue;
2953 return 0;
2954}
2955
2956static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2957 struct usb_os_desc_header *h, void *data,
2958 unsigned len, void *priv)
2959{
2960 struct ffs_function *func = priv;
2961 u8 length = 0;
2962
2963 switch (type) {
2964 case FFS_OS_DESC_EXT_COMPAT: {
2965 struct usb_ext_compat_desc *desc = data;
2966 struct usb_os_desc_table *t;
2967
2968 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2969 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2970 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2971 ARRAY_SIZE(desc->CompatibleID) +
2972 ARRAY_SIZE(desc->SubCompatibleID));
2973 length = sizeof(*desc);
2974 }
2975 break;
2976 case FFS_OS_DESC_EXT_PROP: {
2977 struct usb_ext_prop_desc *desc = data;
2978 struct usb_os_desc_table *t;
2979 struct usb_os_desc_ext_prop *ext_prop;
2980 char *ext_prop_name;
2981 char *ext_prop_data;
2982
2983 t = &func->function.os_desc_table[h->interface];
2984 t->if_id = func->interfaces_nums[h->interface];
2985
2986 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2987 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2988
2989 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2990 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2991 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2992 usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2993 length = ext_prop->name_len + ext_prop->data_len + 14;
2994
2995 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2996 func->ffs->ms_os_descs_ext_prop_name_avail +=
2997 ext_prop->name_len;
2998
2999 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
3000 func->ffs->ms_os_descs_ext_prop_data_avail +=
3001 ext_prop->data_len;
3002 memcpy(ext_prop_data,
3003 usb_ext_prop_data_ptr(data, ext_prop->name_len),
3004 ext_prop->data_len);
3005 /* unicode data reported to the host as "WCHAR"s */
3006 switch (ext_prop->type) {
3007 case USB_EXT_PROP_UNICODE:
3008 case USB_EXT_PROP_UNICODE_ENV:
3009 case USB_EXT_PROP_UNICODE_LINK:
3010 case USB_EXT_PROP_UNICODE_MULTI:
3011 ext_prop->data_len *= 2;
3012 break;
3013 }
3014 ext_prop->data = ext_prop_data;
3015
3016 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3017 ext_prop->name_len);
3018 /* property name reported to the host as "WCHAR"s */
3019 ext_prop->name_len *= 2;
3020 ext_prop->name = ext_prop_name;
3021
3022 t->os_desc->ext_prop_len +=
3023 ext_prop->name_len + ext_prop->data_len + 14;
3024 ++t->os_desc->ext_prop_count;
3025 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3026 }
3027 break;
3028 default:
3029 pr_vdebug("unknown descriptor: %d\n", type);
3030 }
3031
3032 return length;
3033}
3034
3035static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3036 struct usb_configuration *c)
3037{
3038 struct ffs_function *func = ffs_func_from_usb(f);
3039 struct f_fs_opts *ffs_opts =
3040 container_of(f->fi, struct f_fs_opts, func_inst);
3041 int ret;
3042
3043 ENTER();
3044
3045 /*
3046 * Legacy gadget triggers binding in functionfs_ready_callback,
3047 * which already uses locking; taking the same lock here would
3048 * cause a deadlock.
3049 *
3050 * Configfs-enabled gadgets however do need ffs_dev_lock.
3051 */
3052 if (!ffs_opts->no_configfs)
3053 ffs_dev_lock();
3054 ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3055 func->ffs = ffs_opts->dev->ffs_data;
3056 if (!ffs_opts->no_configfs)
3057 ffs_dev_unlock();
3058 if (ret)
3059 return ERR_PTR(ret);
3060
3061 func->conf = c;
3062 func->gadget = c->cdev->gadget;
3063
3064 /*
3065 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3066 * configurations are bound in sequence with list_for_each_entry,
3067 * in each configuration its functions are bound in sequence
3068 * with list_for_each_entry, so we assume no race condition
3069 * with regard to ffs_opts->bound access
3070 */
3071 if (!ffs_opts->refcnt) {
3072 ret = functionfs_bind(func->ffs, c->cdev);
3073 if (ret)
3074 return ERR_PTR(ret);
3075 }
3076 ffs_opts->refcnt++;
3077 func->function.strings = func->ffs->stringtabs;
3078
3079 return ffs_opts;
3080}
3081
3082static int _ffs_func_bind(struct usb_configuration *c,
3083 struct usb_function *f)
3084{
3085 struct ffs_function *func = ffs_func_from_usb(f);
3086 struct ffs_data *ffs = func->ffs;
3087
3088 const int full = !!func->ffs->fs_descs_count;
3089 const int high = !!func->ffs->hs_descs_count;
3090 const int super = !!func->ffs->ss_descs_count;
3091
3092 int fs_len, hs_len, ss_len, ret, i;
3093 struct ffs_ep *eps_ptr;
3094
3095 /* Make it a single chunk, less management later on */
3096 vla_group(d);
3097 vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3098 vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3099 full ? ffs->fs_descs_count + 1 : 0);
3100 vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3101 high ? ffs->hs_descs_count + 1 : 0);
3102 vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3103 super ? ffs->ss_descs_count + 1 : 0);
3104 vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3105 vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3106 c->cdev->use_os_string ? ffs->interfaces_count : 0);
3107 vla_item_with_sz(d, char[16], ext_compat,
3108 c->cdev->use_os_string ? ffs->interfaces_count : 0);
3109 vla_item_with_sz(d, struct usb_os_desc, os_desc,
3110 c->cdev->use_os_string ? ffs->interfaces_count : 0);
3111 vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3112 ffs->ms_os_descs_ext_prop_count);
3113 vla_item_with_sz(d, char, ext_prop_name,
3114 ffs->ms_os_descs_ext_prop_name_len);
3115 vla_item_with_sz(d, char, ext_prop_data,
3116 ffs->ms_os_descs_ext_prop_data_len);
3117 vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3118 char *vlabuf;
3119
3120 ENTER();
3121
3122 /* Has descriptors only for speeds gadget does not support */
3123 if (unlikely(!(full | high | super)))
3124 return -ENOTSUPP;
3125
3126 /* Allocate a single chunk, less management later on */
3127 vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3128 if (unlikely(!vlabuf))
3129 return -ENOMEM;
3130
3131 ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3132 ffs->ms_os_descs_ext_prop_name_avail =
3133 vla_ptr(vlabuf, d, ext_prop_name);
3134 ffs->ms_os_descs_ext_prop_data_avail =
3135 vla_ptr(vlabuf, d, ext_prop_data);
3136
3137 /* Copy descriptors */
3138 memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3139 ffs->raw_descs_length);
3140
3141 memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3142 eps_ptr = vla_ptr(vlabuf, d, eps);
3143 for (i = 0; i < ffs->eps_count; i++)
3144 eps_ptr[i].num = -1;
3145
3146 /* Save pointers
3147 * d_eps == vlabuf, func->eps used to kfree vlabuf later
3148 */
3149 func->eps = vla_ptr(vlabuf, d, eps);
3150 func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3151
3152 /*
3153 * Go through all the endpoint descriptors and allocate
3154 * endpoints first, so that later we can rewrite the endpoint
3155 * numbers without worrying that it may be described later on.
3156 */
3157 if (likely(full)) {
3158 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3159 fs_len = ffs_do_descs(ffs->fs_descs_count,
3160 vla_ptr(vlabuf, d, raw_descs),
3161 d_raw_descs__sz,
3162 __ffs_func_bind_do_descs, func);
3163 if (unlikely(fs_len < 0)) {
3164 ret = fs_len;
3165 goto error;
3166 }
3167 } else {
3168 fs_len = 0;
3169 }
3170
3171 if (likely(high)) {
3172 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3173 hs_len = ffs_do_descs(ffs->hs_descs_count,
3174 vla_ptr(vlabuf, d, raw_descs) + fs_len,
3175 d_raw_descs__sz - fs_len,
3176 __ffs_func_bind_do_descs, func);
3177 if (unlikely(hs_len < 0)) {
3178 ret = hs_len;
3179 goto error;
3180 }
3181 } else {
3182 hs_len = 0;
3183 }
3184
3185 if (likely(super)) {
3186 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3187 ss_len = ffs_do_descs(ffs->ss_descs_count,
3188 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3189 d_raw_descs__sz - fs_len - hs_len,
3190 __ffs_func_bind_do_descs, func);
3191 if (unlikely(ss_len < 0)) {
3192 ret = ss_len;
3193 goto error;
3194 }
3195 } else {
3196 ss_len = 0;
3197 }
3198
3199 /*
3200 * Now handle interface numbers allocation and interface and
3201 * endpoint numbers rewriting. We can do that in one go
3202 * now.
3203 */
3204 ret = ffs_do_descs(ffs->fs_descs_count +
3205 (high ? ffs->hs_descs_count : 0) +
3206 (super ? ffs->ss_descs_count : 0),
3207 vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3208 __ffs_func_bind_do_nums, func);
3209 if (unlikely(ret < 0))
3210 goto error;
3211
3212 func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3213 if (c->cdev->use_os_string) {
3214 for (i = 0; i < ffs->interfaces_count; ++i) {
3215 struct usb_os_desc *desc;
3216
3217 desc = func->function.os_desc_table[i].os_desc =
3218 vla_ptr(vlabuf, d, os_desc) +
3219 i * sizeof(struct usb_os_desc);
3220 desc->ext_compat_id =
3221 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3222 INIT_LIST_HEAD(&desc->ext_prop);
3223 }
3224 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3225 vla_ptr(vlabuf, d, raw_descs) +
3226 fs_len + hs_len + ss_len,
3227 d_raw_descs__sz - fs_len - hs_len -
3228 ss_len,
3229 __ffs_func_bind_do_os_desc, func);
3230 if (unlikely(ret < 0))
3231 goto error;
3232 }
3233 func->function.os_desc_n =
3234 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3235
3236 /* And we're done */
3237 ffs_event_add(ffs, FUNCTIONFS_BIND);
3238 return 0;
3239
3240error:
3241 /* XXX Do we need to release all claimed endpoints here? */
3242 return ret;
3243}
3244
3245static int ffs_func_bind(struct usb_configuration *c,
3246 struct usb_function *f)
3247{
3248 struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3249 struct ffs_function *func = ffs_func_from_usb(f);
3250 int ret;
3251
3252 if (IS_ERR(ffs_opts))
3253 return PTR_ERR(ffs_opts);
3254
3255 ret = _ffs_func_bind(c, f);
3256 if (ret && !--ffs_opts->refcnt)
3257 functionfs_unbind(func->ffs);
3258
3259 return ret;
3260}
3261
3262
3263/* Other USB function hooks *************************************************/
3264
3265static void ffs_reset_work(struct work_struct *work)
3266{
3267 struct ffs_data *ffs = container_of(work,
3268 struct ffs_data, reset_work);
3269 ffs_data_reset(ffs);
3270}
3271
3272static int ffs_func_set_alt(struct usb_function *f,
3273 unsigned interface, unsigned alt)
3274{
3275 struct ffs_function *func = ffs_func_from_usb(f);
3276 struct ffs_data *ffs = func->ffs;
3277 int ret = 0, intf;
3278
3279 if (alt != (unsigned)-1) {
3280 intf = ffs_func_revmap_intf(func, interface);
3281 if (unlikely(intf < 0))
3282 return intf;
3283 }
3284
3285 if (ffs->func)
3286 ffs_func_eps_disable(ffs->func);
3287
3288 if (ffs->state == FFS_DEACTIVATED) {
3289 ffs->state = FFS_CLOSING;
3290 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3291 schedule_work(&ffs->reset_work);
3292 return -ENODEV;
3293 }
3294
3295 if (ffs->state != FFS_ACTIVE)
3296 return -ENODEV;
3297
3298 if (alt == (unsigned)-1) {
3299 ffs->func = NULL;
3300 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3301 return 0;
3302 }
3303
3304 ffs->func = func;
3305 ret = ffs_func_eps_enable(func);
3306 if (likely(ret >= 0))
3307 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3308 return ret;
3309}
3310
3311static void ffs_func_disable(struct usb_function *f)
3312{
3313 ffs_func_set_alt(f, 0, (unsigned)-1);
3314}
3315
3316static int ffs_func_setup(struct usb_function *f,
3317 const struct usb_ctrlrequest *creq)
3318{
3319 struct ffs_function *func = ffs_func_from_usb(f);
3320 struct ffs_data *ffs = func->ffs;
3321 unsigned long flags;
3322 int ret;
3323
3324 ENTER();
3325
3326 pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3327 pr_vdebug("creq->bRequest = %02x\n", creq->bRequest);
3328 pr_vdebug("creq->wValue = %04x\n", le16_to_cpu(creq->wValue));
3329 pr_vdebug("creq->wIndex = %04x\n", le16_to_cpu(creq->wIndex));
3330 pr_vdebug("creq->wLength = %04x\n", le16_to_cpu(creq->wLength));
3331
3332 /*
3333 * Most requests directed to interface go through here
3334 * (notable exceptions are set/get interface) so we need to
3335 * handle them. All other either handled by composite or
3336 * passed to usb_configuration->setup() (if one is set). No
3337 * matter, we will handle requests directed to endpoint here
3338 * as well (as it's straightforward). Other request recipient
3339 * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3340 * is being used.
3341 */
3342 if (ffs->state != FFS_ACTIVE)
3343 return -ENODEV;
3344
3345 switch (creq->bRequestType & USB_RECIP_MASK) {
3346 case USB_RECIP_INTERFACE:
3347 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3348 if (unlikely(ret < 0))
3349 return ret;
3350 break;
3351
3352 case USB_RECIP_ENDPOINT:
3353 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3354 if (unlikely(ret < 0))
3355 return ret;
3356 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3357 ret = func->ffs->eps_addrmap[ret];
3358 break;
3359
3360 default:
3361 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3362 ret = le16_to_cpu(creq->wIndex);
3363 else
3364 return -EOPNOTSUPP;
3365 }
3366
3367 spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3368 ffs->ev.setup = *creq;
3369 ffs->ev.setup.wIndex = cpu_to_le16(ret);
3370 __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3371 spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3372
3373 return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3374}
3375
3376static bool ffs_func_req_match(struct usb_function *f,
3377 const struct usb_ctrlrequest *creq,
3378 bool config0)
3379{
3380 struct ffs_function *func = ffs_func_from_usb(f);
3381
3382 if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3383 return false;
3384
3385 switch (creq->bRequestType & USB_RECIP_MASK) {
3386 case USB_RECIP_INTERFACE:
3387 return (ffs_func_revmap_intf(func,
3388 le16_to_cpu(creq->wIndex)) >= 0);
3389 case USB_RECIP_ENDPOINT:
3390 return (ffs_func_revmap_ep(func,
3391 le16_to_cpu(creq->wIndex)) >= 0);
3392 default:
3393 return (bool) (func->ffs->user_flags &
3394 FUNCTIONFS_ALL_CTRL_RECIP);
3395 }
3396}
3397
3398static void ffs_func_suspend(struct usb_function *f)
3399{
3400 ENTER();
3401 ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3402}
3403
3404static void ffs_func_resume(struct usb_function *f)
3405{
3406 ENTER();
3407 ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3408}
3409
3410
3411/* Endpoint and interface numbers reverse mapping ***************************/
3412
3413static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3414{
3415 num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3416 return num ? num : -EDOM;
3417}
3418
3419static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3420{
3421 short *nums = func->interfaces_nums;
3422 unsigned count = func->ffs->interfaces_count;
3423
3424 for (; count; --count, ++nums) {
3425 if (*nums >= 0 && *nums == intf)
3426 return nums - func->interfaces_nums;
3427 }
3428
3429 return -EDOM;
3430}
3431
3432
3433/* Devices management *******************************************************/
3434
3435static LIST_HEAD(ffs_devices);
3436
3437static struct ffs_dev *_ffs_do_find_dev(const char *name)
3438{
3439 struct ffs_dev *dev;
3440
3441 if (!name)
3442 return NULL;
3443
3444 list_for_each_entry(dev, &ffs_devices, entry) {
3445 if (strcmp(dev->name, name) == 0)
3446 return dev;
3447 }
3448
3449 return NULL;
3450}
3451
3452/*
3453 * ffs_lock must be taken by the caller of this function
3454 */
3455static struct ffs_dev *_ffs_get_single_dev(void)
3456{
3457 struct ffs_dev *dev;
3458
3459 if (list_is_singular(&ffs_devices)) {
3460 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3461 if (dev->single)
3462 return dev;
3463 }
3464
3465 return NULL;
3466}
3467
3468/*
3469 * ffs_lock must be taken by the caller of this function
3470 */
3471static struct ffs_dev *_ffs_find_dev(const char *name)
3472{
3473 struct ffs_dev *dev;
3474
3475 dev = _ffs_get_single_dev();
3476 if (dev)
3477 return dev;
3478
3479 return _ffs_do_find_dev(name);
3480}
3481
3482/* Configfs support *********************************************************/
3483
3484static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3485{
3486 return container_of(to_config_group(item), struct f_fs_opts,
3487 func_inst.group);
3488}
3489
3490static void ffs_attr_release(struct config_item *item)
3491{
3492 struct f_fs_opts *opts = to_ffs_opts(item);
3493
3494 usb_put_function_instance(&opts->func_inst);
3495}
3496
3497static struct configfs_item_operations ffs_item_ops = {
3498 .release = ffs_attr_release,
3499};
3500
3501static const struct config_item_type ffs_func_type = {
3502 .ct_item_ops = &ffs_item_ops,
3503 .ct_owner = THIS_MODULE,
3504};
3505
3506
3507/* Function registration interface ******************************************/
3508
3509static void ffs_free_inst(struct usb_function_instance *f)
3510{
3511 struct f_fs_opts *opts;
3512
3513 opts = to_f_fs_opts(f);
3514 ffs_dev_lock();
3515 _ffs_free_dev(opts->dev);
3516 ffs_dev_unlock();
3517 kfree(opts);
3518}
3519
3520static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3521{
3522 if (strlen(name) >= FIELD_SIZEOF(struct ffs_dev, name))
3523 return -ENAMETOOLONG;
3524 return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3525}
3526
3527static struct usb_function_instance *ffs_alloc_inst(void)
3528{
3529 struct f_fs_opts *opts;
3530 struct ffs_dev *dev;
3531
3532 opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3533 if (!opts)
3534 return ERR_PTR(-ENOMEM);
3535
3536 opts->func_inst.set_inst_name = ffs_set_inst_name;
3537 opts->func_inst.free_func_inst = ffs_free_inst;
3538 ffs_dev_lock();
3539 dev = _ffs_alloc_dev();
3540 ffs_dev_unlock();
3541 if (IS_ERR(dev)) {
3542 kfree(opts);
3543 return ERR_CAST(dev);
3544 }
3545 opts->dev = dev;
3546 dev->opts = opts;
3547
3548 config_group_init_type_name(&opts->func_inst.group, "",
3549 &ffs_func_type);
3550 return &opts->func_inst;
3551}
3552
3553static void ffs_free(struct usb_function *f)
3554{
3555 kfree(ffs_func_from_usb(f));
3556}
3557
3558static void ffs_func_unbind(struct usb_configuration *c,
3559 struct usb_function *f)
3560{
3561 struct ffs_function *func = ffs_func_from_usb(f);
3562 struct ffs_data *ffs = func->ffs;
3563 struct f_fs_opts *opts =
3564 container_of(f->fi, struct f_fs_opts, func_inst);
3565 struct ffs_ep *ep = func->eps;
3566 unsigned count = ffs->eps_count;
3567 unsigned long flags;
3568
3569 ENTER();
3570 if (ffs->func == func) {
3571 ffs_func_eps_disable(func);
3572 ffs->func = NULL;
3573 }
3574
3575 if (!--opts->refcnt)
3576 functionfs_unbind(ffs);
3577
3578 /* cleanup after autoconfig */
3579 spin_lock_irqsave(&func->ffs->eps_lock, flags);
3580 while (count--) {
3581 if (ep->ep && ep->req)
3582 usb_ep_free_request(ep->ep, ep->req);
3583 ep->req = NULL;
3584 ++ep;
3585 }
3586 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3587 kfree(func->eps);
3588 func->eps = NULL;
3589 /*
3590 * eps, descriptors and interfaces_nums are allocated in the
3591 * same chunk so only one free is required.
3592 */
3593 func->function.fs_descriptors = NULL;
3594 func->function.hs_descriptors = NULL;
3595 func->function.ss_descriptors = NULL;
3596 func->interfaces_nums = NULL;
3597
3598 ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3599}
3600
3601static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3602{
3603 struct ffs_function *func;
3604
3605 ENTER();
3606
3607 func = kzalloc(sizeof(*func), GFP_KERNEL);
3608 if (unlikely(!func))
3609 return ERR_PTR(-ENOMEM);
3610
3611 func->function.name = "Function FS Gadget";
3612
3613 func->function.bind = ffs_func_bind;
3614 func->function.unbind = ffs_func_unbind;
3615 func->function.set_alt = ffs_func_set_alt;
3616 func->function.disable = ffs_func_disable;
3617 func->function.setup = ffs_func_setup;
3618 func->function.req_match = ffs_func_req_match;
3619 func->function.suspend = ffs_func_suspend;
3620 func->function.resume = ffs_func_resume;
3621 func->function.free_func = ffs_free;
3622
3623 return &func->function;
3624}
3625
3626/*
3627 * ffs_lock must be taken by the caller of this function
3628 */
3629static struct ffs_dev *_ffs_alloc_dev(void)
3630{
3631 struct ffs_dev *dev;
3632 int ret;
3633
3634 if (_ffs_get_single_dev())
3635 return ERR_PTR(-EBUSY);
3636
3637 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3638 if (!dev)
3639 return ERR_PTR(-ENOMEM);
3640
3641 if (list_empty(&ffs_devices)) {
3642 ret = functionfs_init();
3643 if (ret) {
3644 kfree(dev);
3645 return ERR_PTR(ret);
3646 }
3647 }
3648
3649 list_add(&dev->entry, &ffs_devices);
3650
3651 return dev;
3652}
3653
3654int ffs_name_dev(struct ffs_dev *dev, const char *name)
3655{
3656 struct ffs_dev *existing;
3657 int ret = 0;
3658
3659 ffs_dev_lock();
3660
3661 existing = _ffs_do_find_dev(name);
3662 if (!existing)
3663 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3664 else if (existing != dev)
3665 ret = -EBUSY;
3666
3667 ffs_dev_unlock();
3668
3669 return ret;
3670}
3671EXPORT_SYMBOL_GPL(ffs_name_dev);
3672
3673int ffs_single_dev(struct ffs_dev *dev)
3674{
3675 int ret;
3676
3677 ret = 0;
3678 ffs_dev_lock();
3679
3680 if (!list_is_singular(&ffs_devices))
3681 ret = -EBUSY;
3682 else
3683 dev->single = true;
3684
3685 ffs_dev_unlock();
3686 return ret;
3687}
3688EXPORT_SYMBOL_GPL(ffs_single_dev);
3689
3690/*
3691 * ffs_lock must be taken by the caller of this function
3692 */
3693static void _ffs_free_dev(struct ffs_dev *dev)
3694{
3695 list_del(&dev->entry);
3696
3697 /* Clear the private_data pointer to stop incorrect dev access */
3698 if (dev->ffs_data)
3699 dev->ffs_data->private_data = NULL;
3700
3701 kfree(dev);
3702 if (list_empty(&ffs_devices))
3703 functionfs_cleanup();
3704}
3705
3706static void *ffs_acquire_dev(const char *dev_name)
3707{
3708 struct ffs_dev *ffs_dev;
3709
3710 ENTER();
3711 ffs_dev_lock();
3712
3713 ffs_dev = _ffs_find_dev(dev_name);
3714 if (!ffs_dev)
3715 ffs_dev = ERR_PTR(-ENOENT);
3716 else if (ffs_dev->mounted)
3717 ffs_dev = ERR_PTR(-EBUSY);
3718 else if (ffs_dev->ffs_acquire_dev_callback &&
3719 ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3720 ffs_dev = ERR_PTR(-ENOENT);
3721 else
3722 ffs_dev->mounted = true;
3723
3724 ffs_dev_unlock();
3725 return ffs_dev;
3726}
3727
3728static void ffs_release_dev(struct ffs_data *ffs_data)
3729{
3730 struct ffs_dev *ffs_dev;
3731
3732 ENTER();
3733 ffs_dev_lock();
3734
3735 ffs_dev = ffs_data->private_data;
3736 if (ffs_dev) {
3737 ffs_dev->mounted = false;
3738
3739 if (ffs_dev->ffs_release_dev_callback)
3740 ffs_dev->ffs_release_dev_callback(ffs_dev);
3741 }
3742
3743 ffs_dev_unlock();
3744}
3745
3746static int ffs_ready(struct ffs_data *ffs)
3747{
3748 struct ffs_dev *ffs_obj;
3749 int ret = 0;
3750
3751 ENTER();
3752 ffs_dev_lock();
3753
3754 ffs_obj = ffs->private_data;
3755 if (!ffs_obj) {
3756 ret = -EINVAL;
3757 goto done;
3758 }
3759 if (WARN_ON(ffs_obj->desc_ready)) {
3760 ret = -EBUSY;
3761 goto done;
3762 }
3763
3764 ffs_obj->desc_ready = true;
3765 ffs_obj->ffs_data = ffs;
3766
3767 if (ffs_obj->ffs_ready_callback) {
3768 ret = ffs_obj->ffs_ready_callback(ffs);
3769 if (ret)
3770 goto done;
3771 }
3772
3773 set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3774done:
3775 ffs_dev_unlock();
3776 return ret;
3777}
3778
3779static void ffs_closed(struct ffs_data *ffs)
3780{
3781 struct ffs_dev *ffs_obj;
3782 struct f_fs_opts *opts;
3783 struct config_item *ci;
3784
3785 ENTER();
3786 ffs_dev_lock();
3787
3788 ffs_obj = ffs->private_data;
3789 if (!ffs_obj)
3790 goto done;
3791
3792 ffs_obj->desc_ready = false;
3793 ffs_obj->ffs_data = NULL;
3794
3795 if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3796 ffs_obj->ffs_closed_callback)
3797 ffs_obj->ffs_closed_callback(ffs);
3798
3799 if (ffs_obj->opts)
3800 opts = ffs_obj->opts;
3801 else
3802 goto done;
3803
3804 if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3805 || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3806 goto done;
3807
3808 ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3809 ffs_dev_unlock();
3810
3811 if (test_bit(FFS_FL_BOUND, &ffs->flags))
3812 unregister_gadget_item(ci);
3813 return;
3814done:
3815 ffs_dev_unlock();
3816}
3817
3818/* Misc helper functions ****************************************************/
3819
3820static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3821{
3822 return nonblock
3823 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3824 : mutex_lock_interruptible(mutex);
3825}
3826
3827static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3828{
3829 char *data;
3830
3831 if (unlikely(!len))
3832 return NULL;
3833
3834 data = kmalloc(len, GFP_KERNEL);
3835 if (unlikely(!data))
3836 return ERR_PTR(-ENOMEM);
3837
3838 if (unlikely(copy_from_user(data, buf, len))) {
3839 kfree(data);
3840 return ERR_PTR(-EFAULT);
3841 }
3842
3843 pr_vdebug("Buffer from user space:\n");
3844 ffs_dump_mem("", data, len);
3845
3846 return data;
3847}
3848
3849DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3850MODULE_LICENSE("GPL");
3851MODULE_AUTHOR("Michal Nazarewicz");