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WIP FPC-III support
[linux/fpc-iii.git] / drivers / usb / gadget / function / f_fs.c
blob801a8b668a35a03fb9a73cf60a1769a3738ea735
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/kthread.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 */
47 static void ffs_data_get(struct ffs_data *ffs);
48 static void ffs_data_put(struct ffs_data *ffs);
49 /* Creates new ffs_data object. */
50 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
51 __attribute__((malloc));
52
53 /* Opened counter handling. */
54 static void ffs_data_opened(struct ffs_data *ffs);
55 static void ffs_data_closed(struct ffs_data *ffs);
56
57 /* Called with ffs->mutex held; take over ownership of data. */
58 static int __must_check
59 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
60 static int __must_check
61 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
62
63
64 /* The function structure ***************************************************/
65
66 struct ffs_ep;
67
68 struct 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
81 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
82 {
83 return container_of(f, struct ffs_function, function);
84 }
85
86
87 static inline enum ffs_setup_state
88 ffs_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
95 static void ffs_func_eps_disable(struct ffs_function *func);
96 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
97
98 static int ffs_func_bind(struct usb_configuration *,
99 struct usb_function *);
100 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
101 static void ffs_func_disable(struct usb_function *);
102 static int ffs_func_setup(struct usb_function *,
103 const struct usb_ctrlrequest *);
104 static bool ffs_func_req_match(struct usb_function *,
105 const struct usb_ctrlrequest *,
106 bool config0);
107 static void ffs_func_suspend(struct usb_function *);
108 static void ffs_func_resume(struct usb_function *);
109
110
111 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
112 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
113
114
115 /* The endpoints structures *************************************************/
116
117 struct 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
129 struct 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 * ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
166 * ◦ __ffs_epfile_read_buffered: nop
167 * ◦ __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 * ◦ __ffs_epfile_read_buffer_free: nop
171 * ◦ __ffs_epfile_read_buffered: go to ptr == NULL
172 * ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
173 * ◦ reading finishes: n/a, not in ‘and reading’ state
174 * • ptr == buf:
175 * ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
176 * ◦ __ffs_epfile_read_buffered: go to ptr == NULL and reading
177 * ◦ __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 * ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
182 * ◦ __ffs_epfile_read_buffered: n/a, mutex is held
183 * ◦ __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 * ◦ __ffs_epfile_read_buffer_free: nop
189 * ◦ __ffs_epfile_read_buffered: n/a, mutex is held
190 * ◦ __ffs_epfile_read_data: n/a, mutex is held
191 * ◦ 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
204 struct ffs_buffer {
205 size_t length;
206 char *data;
207 char storage[];
208 };
209
210 /* ffs_io_data structure ***************************************************/
211
212 struct 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
232 struct ffs_desc_helper {
233 struct ffs_data *ffs;
234 unsigned interfaces_count;
235 unsigned eps_count;
236 };
237
238 static int __must_check ffs_epfiles_create(struct ffs_data *ffs);
239 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
240
241 static struct dentry *
242 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
243 const struct file_operations *fops);
244
245 /* Devices management *******************************************************/
246
247 DEFINE_MUTEX(ffs_lock);
248 EXPORT_SYMBOL_GPL(ffs_lock);
249
250 static struct ffs_dev *_ffs_find_dev(const char *name);
251 static struct ffs_dev *_ffs_alloc_dev(void);
252 static void _ffs_free_dev(struct ffs_dev *dev);
253 static void *ffs_acquire_dev(const char *dev_name);
254 static void ffs_release_dev(struct ffs_data *ffs_data);
255 static int ffs_ready(struct ffs_data *ffs);
256 static void ffs_closed(struct ffs_data *ffs);
257
258 /* Misc helper functions ****************************************************/
259
260 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
261 __attribute__((warn_unused_result, nonnull));
262 static 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
268 static 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
275 static 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 (ret < 0)
300 return ret;
301
302 ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
303 if (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
312 static 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
325 static 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 (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 (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 (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 (ret < 0)
372 break;
373
374 ret = ffs_epfiles_create(ffs);
375 if (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 (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;
448 done_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. */
467 static 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 copy_to_user(buf, events, size) ? -EFAULT : size;
499 }
500
501 static 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 (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 (!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 (len) {
571 data = kmalloc(len, GFP_KERNEL);
572 if (!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 ((ret > 0) && (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);
599 done_mutex:
600 mutex_unlock(&ffs->mutex);
601 kfree(data);
602 return ret;
603 }
604
605 static 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 (ffs->state == FFS_CLOSING)
612 return -EBUSY;
613
614 file->private_data = ffs;
615 ffs_data_opened(ffs);
616
617 return 0;
618 }
619
620 static 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
631 static 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
651 static __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 (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 break;
682
683 case FFS_CLOSING:
684 break;
685 case FFS_DEACTIVATED:
686 break;
687 }
688
689 mutex_unlock(&ffs->mutex);
690
691 return mask;
692 }
693
694 static const struct file_operations ffs_ep0_operations = {
695 .llseek = no_llseek,
696
697 .open = ffs_ep0_open,
698 .write = ffs_ep0_write,
699 .read = ffs_ep0_read,
700 .release = ffs_ep0_release,
701 .unlocked_ioctl = ffs_ep0_ioctl,
702 .poll = ffs_ep0_poll,
703 };
704
705
706 /* "Normal" endpoints operations ********************************************/
707
708 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
709 {
710 ENTER();
711 if (req->context) {
712 struct ffs_ep *ep = _ep->driver_data;
713 ep->status = req->status ? req->status : req->actual;
714 complete(req->context);
715 }
716 }
717
718 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
719 {
720 ssize_t ret = copy_to_iter(data, data_len, iter);
721 if (ret == data_len)
722 return ret;
723
724 if (iov_iter_count(iter))
725 return -EFAULT;
726
727 /*
728 * Dear user space developer!
729 *
730 * TL;DR: To stop getting below error message in your kernel log, change
731 * user space code using functionfs to align read buffers to a max
732 * packet size.
733 *
734 * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
735 * packet size. When unaligned buffer is passed to functionfs, it
736 * internally uses a larger, aligned buffer so that such UDCs are happy.
737 *
738 * Unfortunately, this means that host may send more data than was
739 * requested in read(2) system call. f_fs doesn’t know what to do with
740 * that excess data so it simply drops it.
741 *
742 * Was the buffer aligned in the first place, no such problem would
743 * happen.
744 *
745 * Data may be dropped only in AIO reads. Synchronous reads are handled
746 * by splitting a request into multiple parts. This splitting may still
747 * be a problem though so it’s likely best to align the buffer
748 * regardless of it being AIO or not..
749 *
750 * This only affects OUT endpoints, i.e. reading data with a read(2),
751 * aio_read(2) etc. system calls. Writing data to an IN endpoint is not
752 * affected.
753 */
754 pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
755 "Align read buffer size to max packet size to avoid the problem.\n",
756 data_len, ret);
757
758 return ret;
759 }
760
761 /*
762 * allocate a virtually contiguous buffer and create a scatterlist describing it
763 * @sg_table - pointer to a place to be filled with sg_table contents
764 * @size - required buffer size
765 */
766 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
767 {
768 struct page **pages;
769 void *vaddr, *ptr;
770 unsigned int n_pages;
771 int i;
772
773 vaddr = vmalloc(sz);
774 if (!vaddr)
775 return NULL;
776
777 n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
778 pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
779 if (!pages) {
780 vfree(vaddr);
781
782 return NULL;
783 }
784 for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
785 pages[i] = vmalloc_to_page(ptr);
786
787 if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
788 kvfree(pages);
789 vfree(vaddr);
790
791 return NULL;
792 }
793 kvfree(pages);
794
795 return vaddr;
796 }
797
798 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
799 size_t data_len)
800 {
801 if (io_data->use_sg)
802 return ffs_build_sg_list(&io_data->sgt, data_len);
803
804 return kmalloc(data_len, GFP_KERNEL);
805 }
806
807 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
808 {
809 if (!io_data->buf)
810 return;
811
812 if (io_data->use_sg) {
813 sg_free_table(&io_data->sgt);
814 vfree(io_data->buf);
815 } else {
816 kfree(io_data->buf);
817 }
818 }
819
820 static void ffs_user_copy_worker(struct work_struct *work)
821 {
822 struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
823 work);
824 int ret = io_data->req->status ? io_data->req->status :
825 io_data->req->actual;
826 bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
827
828 if (io_data->read && ret > 0) {
829 kthread_use_mm(io_data->mm);
830 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
831 kthread_unuse_mm(io_data->mm);
832 }
833
834 io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
835
836 if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
837 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
838
839 usb_ep_free_request(io_data->ep, io_data->req);
840
841 if (io_data->read)
842 kfree(io_data->to_free);
843 ffs_free_buffer(io_data);
844 kfree(io_data);
845 }
846
847 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
848 struct usb_request *req)
849 {
850 struct ffs_io_data *io_data = req->context;
851 struct ffs_data *ffs = io_data->ffs;
852
853 ENTER();
854
855 INIT_WORK(&io_data->work, ffs_user_copy_worker);
856 queue_work(ffs->io_completion_wq, &io_data->work);
857 }
858
859 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
860 {
861 /*
862 * See comment in struct ffs_epfile for full read_buffer pointer
863 * synchronisation story.
864 */
865 struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
866 if (buf && buf != READ_BUFFER_DROP)
867 kfree(buf);
868 }
869
870 /* Assumes epfile->mutex is held. */
871 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
872 struct iov_iter *iter)
873 {
874 /*
875 * Null out epfile->read_buffer so ffs_func_eps_disable does not free
876 * the buffer while we are using it. See comment in struct ffs_epfile
877 * for full read_buffer pointer synchronisation story.
878 */
879 struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
880 ssize_t ret;
881 if (!buf || buf == READ_BUFFER_DROP)
882 return 0;
883
884 ret = copy_to_iter(buf->data, buf->length, iter);
885 if (buf->length == ret) {
886 kfree(buf);
887 return ret;
888 }
889
890 if (iov_iter_count(iter)) {
891 ret = -EFAULT;
892 } else {
893 buf->length -= ret;
894 buf->data += ret;
895 }
896
897 if (cmpxchg(&epfile->read_buffer, NULL, buf))
898 kfree(buf);
899
900 return ret;
901 }
902
903 /* Assumes epfile->mutex is held. */
904 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
905 void *data, int data_len,
906 struct iov_iter *iter)
907 {
908 struct ffs_buffer *buf;
909
910 ssize_t ret = copy_to_iter(data, data_len, iter);
911 if (data_len == ret)
912 return ret;
913
914 if (iov_iter_count(iter))
915 return -EFAULT;
916
917 /* See ffs_copy_to_iter for more context. */
918 pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
919 data_len, ret);
920
921 data_len -= ret;
922 buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
923 if (!buf)
924 return -ENOMEM;
925 buf->length = data_len;
926 buf->data = buf->storage;
927 memcpy(buf->storage, data + ret, data_len);
928
929 /*
930 * At this point read_buffer is NULL or READ_BUFFER_DROP (if
931 * ffs_func_eps_disable has been called in the meanwhile). See comment
932 * in struct ffs_epfile for full read_buffer pointer synchronisation
933 * story.
934 */
935 if (cmpxchg(&epfile->read_buffer, NULL, buf))
936 kfree(buf);
937
938 return ret;
939 }
940
941 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
942 {
943 struct ffs_epfile *epfile = file->private_data;
944 struct usb_request *req;
945 struct ffs_ep *ep;
946 char *data = NULL;
947 ssize_t ret, data_len = -EINVAL;
948 int halt;
949
950 /* Are we still active? */
951 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
952 return -ENODEV;
953
954 /* Wait for endpoint to be enabled */
955 ep = epfile->ep;
956 if (!ep) {
957 if (file->f_flags & O_NONBLOCK)
958 return -EAGAIN;
959
960 ret = wait_event_interruptible(
961 epfile->ffs->wait, (ep = epfile->ep));
962 if (ret)
963 return -EINTR;
964 }
965
966 /* Do we halt? */
967 halt = (!io_data->read == !epfile->in);
968 if (halt && epfile->isoc)
969 return -EINVAL;
970
971 /* We will be using request and read_buffer */
972 ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
973 if (ret)
974 goto error;
975
976 /* Allocate & copy */
977 if (!halt) {
978 struct usb_gadget *gadget;
979
980 /*
981 * Do we have buffered data from previous partial read? Check
982 * that for synchronous case only because we do not have
983 * facility to ‘wake up’ a pending asynchronous read and push
984 * buffered data to it which we would need to make things behave
985 * consistently.
986 */
987 if (!io_data->aio && io_data->read) {
988 ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
989 if (ret)
990 goto error_mutex;
991 }
992
993 /*
994 * if we _do_ wait above, the epfile->ffs->gadget might be NULL
995 * before the waiting completes, so do not assign to 'gadget'
996 * earlier
997 */
998 gadget = epfile->ffs->gadget;
999
1000 spin_lock_irq(&epfile->ffs->eps_lock);
1001 /* In the meantime, endpoint got disabled or changed. */
1002 if (epfile->ep != ep) {
1003 ret = -ESHUTDOWN;
1004 goto error_lock;
1005 }
1006 data_len = iov_iter_count(&io_data->data);
1007 /*
1008 * Controller may require buffer size to be aligned to
1009 * maxpacketsize of an out endpoint.
1010 */
1011 if (io_data->read)
1012 data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1013
1014 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1015 spin_unlock_irq(&epfile->ffs->eps_lock);
1016
1017 data = ffs_alloc_buffer(io_data, data_len);
1018 if (!data) {
1019 ret = -ENOMEM;
1020 goto error_mutex;
1021 }
1022 if (!io_data->read &&
1023 !copy_from_iter_full(data, data_len, &io_data->data)) {
1024 ret = -EFAULT;
1025 goto error_mutex;
1026 }
1027 }
1028
1029 spin_lock_irq(&epfile->ffs->eps_lock);
1030
1031 if (epfile->ep != ep) {
1032 /* In the meantime, endpoint got disabled or changed. */
1033 ret = -ESHUTDOWN;
1034 } else if (halt) {
1035 ret = usb_ep_set_halt(ep->ep);
1036 if (!ret)
1037 ret = -EBADMSG;
1038 } else if (data_len == -EINVAL) {
1039 /*
1040 * Sanity Check: even though data_len can't be used
1041 * uninitialized at the time I write this comment, some
1042 * compilers complain about this situation.
1043 * In order to keep the code clean from warnings, data_len is
1044 * being initialized to -EINVAL during its declaration, which
1045 * means we can't rely on compiler anymore to warn no future
1046 * changes won't result in data_len being used uninitialized.
1047 * For such reason, we're adding this redundant sanity check
1048 * here.
1049 */
1050 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1051 ret = -EINVAL;
1052 } else if (!io_data->aio) {
1053 DECLARE_COMPLETION_ONSTACK(done);
1054 bool interrupted = false;
1055
1056 req = ep->req;
1057 if (io_data->use_sg) {
1058 req->buf = NULL;
1059 req->sg = io_data->sgt.sgl;
1060 req->num_sgs = io_data->sgt.nents;
1061 } else {
1062 req->buf = data;
1063 req->num_sgs = 0;
1064 }
1065 req->length = data_len;
1066
1067 io_data->buf = data;
1068
1069 req->context = &done;
1070 req->complete = ffs_epfile_io_complete;
1071
1072 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1073 if (ret < 0)
1074 goto error_lock;
1075
1076 spin_unlock_irq(&epfile->ffs->eps_lock);
1077
1078 if (wait_for_completion_interruptible(&done)) {
1079 /*
1080 * To avoid race condition with ffs_epfile_io_complete,
1081 * dequeue the request first then check
1082 * status. usb_ep_dequeue API should guarantee no race
1083 * condition with req->complete callback.
1084 */
1085 usb_ep_dequeue(ep->ep, req);
1086 wait_for_completion(&done);
1087 interrupted = ep->status < 0;
1088 }
1089
1090 if (interrupted)
1091 ret = -EINTR;
1092 else if (io_data->read && ep->status > 0)
1093 ret = __ffs_epfile_read_data(epfile, data, ep->status,
1094 &io_data->data);
1095 else
1096 ret = ep->status;
1097 goto error_mutex;
1098 } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1099 ret = -ENOMEM;
1100 } else {
1101 if (io_data->use_sg) {
1102 req->buf = NULL;
1103 req->sg = io_data->sgt.sgl;
1104 req->num_sgs = io_data->sgt.nents;
1105 } else {
1106 req->buf = data;
1107 req->num_sgs = 0;
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 (ret) {
1121 io_data->req = NULL;
1122 usb_ep_free_request(ep->ep, req);
1123 goto error_lock;
1124 }
1125
1126 ret = -EIOCBQUEUED;
1127 /*
1128 * Do not kfree the buffer in this function. It will be freed
1129 * by ffs_user_copy_worker.
1130 */
1131 data = NULL;
1132 }
1133
1134 error_lock:
1135 spin_unlock_irq(&epfile->ffs->eps_lock);
1136 error_mutex:
1137 mutex_unlock(&epfile->mutex);
1138 error:
1139 if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1140 ffs_free_buffer(io_data);
1141 return ret;
1142 }
1143
1144 static int
1145 ffs_epfile_open(struct inode *inode, struct file *file)
1146 {
1147 struct ffs_epfile *epfile = inode->i_private;
1148
1149 ENTER();
1150
1151 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1152 return -ENODEV;
1153
1154 file->private_data = epfile;
1155 ffs_data_opened(epfile->ffs);
1156
1157 return 0;
1158 }
1159
1160 static int ffs_aio_cancel(struct kiocb *kiocb)
1161 {
1162 struct ffs_io_data *io_data = kiocb->private;
1163 struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1164 unsigned long flags;
1165 int value;
1166
1167 ENTER();
1168
1169 spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1170
1171 if (io_data && io_data->ep && io_data->req)
1172 value = usb_ep_dequeue(io_data->ep, io_data->req);
1173 else
1174 value = -EINVAL;
1175
1176 spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1177
1178 return value;
1179 }
1180
1181 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1182 {
1183 struct ffs_io_data io_data, *p = &io_data;
1184 ssize_t res;
1185
1186 ENTER();
1187
1188 if (!is_sync_kiocb(kiocb)) {
1189 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1190 if (!p)
1191 return -ENOMEM;
1192 p->aio = true;
1193 } else {
1194 memset(p, 0, sizeof(*p));
1195 p->aio = false;
1196 }
1197
1198 p->read = false;
1199 p->kiocb = kiocb;
1200 p->data = *from;
1201 p->mm = current->mm;
1202
1203 kiocb->private = p;
1204
1205 if (p->aio)
1206 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1207
1208 res = ffs_epfile_io(kiocb->ki_filp, p);
1209 if (res == -EIOCBQUEUED)
1210 return res;
1211 if (p->aio)
1212 kfree(p);
1213 else
1214 *from = p->data;
1215 return res;
1216 }
1217
1218 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1219 {
1220 struct ffs_io_data io_data, *p = &io_data;
1221 ssize_t res;
1222
1223 ENTER();
1224
1225 if (!is_sync_kiocb(kiocb)) {
1226 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1227 if (!p)
1228 return -ENOMEM;
1229 p->aio = true;
1230 } else {
1231 memset(p, 0, sizeof(*p));
1232 p->aio = false;
1233 }
1234
1235 p->read = true;
1236 p->kiocb = kiocb;
1237 if (p->aio) {
1238 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1239 if (!p->to_free) {
1240 kfree(p);
1241 return -ENOMEM;
1242 }
1243 } else {
1244 p->data = *to;
1245 p->to_free = NULL;
1246 }
1247 p->mm = current->mm;
1248
1249 kiocb->private = p;
1250
1251 if (p->aio)
1252 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1253
1254 res = ffs_epfile_io(kiocb->ki_filp, p);
1255 if (res == -EIOCBQUEUED)
1256 return res;
1257
1258 if (p->aio) {
1259 kfree(p->to_free);
1260 kfree(p);
1261 } else {
1262 *to = p->data;
1263 }
1264 return res;
1265 }
1266
1267 static int
1268 ffs_epfile_release(struct inode *inode, struct file *file)
1269 {
1270 struct ffs_epfile *epfile = inode->i_private;
1271
1272 ENTER();
1273
1274 __ffs_epfile_read_buffer_free(epfile);
1275 ffs_data_closed(epfile->ffs);
1276
1277 return 0;
1278 }
1279
1280 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1281 unsigned long value)
1282 {
1283 struct ffs_epfile *epfile = file->private_data;
1284 struct ffs_ep *ep;
1285 int ret;
1286
1287 ENTER();
1288
1289 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1290 return -ENODEV;
1291
1292 /* Wait for endpoint to be enabled */
1293 ep = epfile->ep;
1294 if (!ep) {
1295 if (file->f_flags & O_NONBLOCK)
1296 return -EAGAIN;
1297
1298 ret = wait_event_interruptible(
1299 epfile->ffs->wait, (ep = epfile->ep));
1300 if (ret)
1301 return -EINTR;
1302 }
1303
1304 spin_lock_irq(&epfile->ffs->eps_lock);
1305
1306 /* In the meantime, endpoint got disabled or changed. */
1307 if (epfile->ep != ep) {
1308 spin_unlock_irq(&epfile->ffs->eps_lock);
1309 return -ESHUTDOWN;
1310 }
1311
1312 switch (code) {
1313 case FUNCTIONFS_FIFO_STATUS:
1314 ret = usb_ep_fifo_status(epfile->ep->ep);
1315 break;
1316 case FUNCTIONFS_FIFO_FLUSH:
1317 usb_ep_fifo_flush(epfile->ep->ep);
1318 ret = 0;
1319 break;
1320 case FUNCTIONFS_CLEAR_HALT:
1321 ret = usb_ep_clear_halt(epfile->ep->ep);
1322 break;
1323 case FUNCTIONFS_ENDPOINT_REVMAP:
1324 ret = epfile->ep->num;
1325 break;
1326 case FUNCTIONFS_ENDPOINT_DESC:
1327 {
1328 int desc_idx;
1329 struct usb_endpoint_descriptor desc1, *desc;
1330
1331 switch (epfile->ffs->gadget->speed) {
1332 case USB_SPEED_SUPER:
1333 case USB_SPEED_SUPER_PLUS:
1334 desc_idx = 2;
1335 break;
1336 case USB_SPEED_HIGH:
1337 desc_idx = 1;
1338 break;
1339 default:
1340 desc_idx = 0;
1341 }
1342
1343 desc = epfile->ep->descs[desc_idx];
1344 memcpy(&desc1, desc, desc->bLength);
1345
1346 spin_unlock_irq(&epfile->ffs->eps_lock);
1347 ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
1348 if (ret)
1349 ret = -EFAULT;
1350 return ret;
1351 }
1352 default:
1353 ret = -ENOTTY;
1354 }
1355 spin_unlock_irq(&epfile->ffs->eps_lock);
1356
1357 return ret;
1358 }
1359
1360 static const struct file_operations ffs_epfile_operations = {
1361 .llseek = no_llseek,
1362
1363 .open = ffs_epfile_open,
1364 .write_iter = ffs_epfile_write_iter,
1365 .read_iter = ffs_epfile_read_iter,
1366 .release = ffs_epfile_release,
1367 .unlocked_ioctl = ffs_epfile_ioctl,
1368 .compat_ioctl = compat_ptr_ioctl,
1369 };
1370
1371
1372 /* File system and super block operations ***********************************/
1373
1374 /*
1375 * Mounting the file system creates a controller file, used first for
1376 * function configuration then later for event monitoring.
1377 */
1378
1379 static struct inode *__must_check
1380 ffs_sb_make_inode(struct super_block *sb, void *data,
1381 const struct file_operations *fops,
1382 const struct inode_operations *iops,
1383 struct ffs_file_perms *perms)
1384 {
1385 struct inode *inode;
1386
1387 ENTER();
1388
1389 inode = new_inode(sb);
1390
1391 if (inode) {
1392 struct timespec64 ts = current_time(inode);
1393
1394 inode->i_ino = get_next_ino();
1395 inode->i_mode = perms->mode;
1396 inode->i_uid = perms->uid;
1397 inode->i_gid = perms->gid;
1398 inode->i_atime = ts;
1399 inode->i_mtime = ts;
1400 inode->i_ctime = ts;
1401 inode->i_private = data;
1402 if (fops)
1403 inode->i_fop = fops;
1404 if (iops)
1405 inode->i_op = iops;
1406 }
1407
1408 return inode;
1409 }
1410
1411 /* Create "regular" file */
1412 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1413 const char *name, void *data,
1414 const struct file_operations *fops)
1415 {
1416 struct ffs_data *ffs = sb->s_fs_info;
1417 struct dentry *dentry;
1418 struct inode *inode;
1419
1420 ENTER();
1421
1422 dentry = d_alloc_name(sb->s_root, name);
1423 if (!dentry)
1424 return NULL;
1425
1426 inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1427 if (!inode) {
1428 dput(dentry);
1429 return NULL;
1430 }
1431
1432 d_add(dentry, inode);
1433 return dentry;
1434 }
1435
1436 /* Super block */
1437 static const struct super_operations ffs_sb_operations = {
1438 .statfs = simple_statfs,
1439 .drop_inode = generic_delete_inode,
1440 };
1441
1442 struct ffs_sb_fill_data {
1443 struct ffs_file_perms perms;
1444 umode_t root_mode;
1445 const char *dev_name;
1446 bool no_disconnect;
1447 struct ffs_data *ffs_data;
1448 };
1449
1450 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1451 {
1452 struct ffs_sb_fill_data *data = fc->fs_private;
1453 struct inode *inode;
1454 struct ffs_data *ffs = data->ffs_data;
1455
1456 ENTER();
1457
1458 ffs->sb = sb;
1459 data->ffs_data = NULL;
1460 sb->s_fs_info = ffs;
1461 sb->s_blocksize = PAGE_SIZE;
1462 sb->s_blocksize_bits = PAGE_SHIFT;
1463 sb->s_magic = FUNCTIONFS_MAGIC;
1464 sb->s_op = &ffs_sb_operations;
1465 sb->s_time_gran = 1;
1466
1467 /* Root inode */
1468 data->perms.mode = data->root_mode;
1469 inode = ffs_sb_make_inode(sb, NULL,
1470 &simple_dir_operations,
1471 &simple_dir_inode_operations,
1472 &data->perms);
1473 sb->s_root = d_make_root(inode);
1474 if (!sb->s_root)
1475 return -ENOMEM;
1476
1477 /* EP0 file */
1478 if (!ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations))
1479 return -ENOMEM;
1480
1481 return 0;
1482 }
1483
1484 enum {
1485 Opt_no_disconnect,
1486 Opt_rmode,
1487 Opt_fmode,
1488 Opt_mode,
1489 Opt_uid,
1490 Opt_gid,
1491 };
1492
1493 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1494 fsparam_bool ("no_disconnect", Opt_no_disconnect),
1495 fsparam_u32 ("rmode", Opt_rmode),
1496 fsparam_u32 ("fmode", Opt_fmode),
1497 fsparam_u32 ("mode", Opt_mode),
1498 fsparam_u32 ("uid", Opt_uid),
1499 fsparam_u32 ("gid", Opt_gid),
1500 {}
1501 };
1502
1503 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1504 {
1505 struct ffs_sb_fill_data *data = fc->fs_private;
1506 struct fs_parse_result result;
1507 int opt;
1508
1509 ENTER();
1510
1511 opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1512 if (opt < 0)
1513 return opt;
1514
1515 switch (opt) {
1516 case Opt_no_disconnect:
1517 data->no_disconnect = result.boolean;
1518 break;
1519 case Opt_rmode:
1520 data->root_mode = (result.uint_32 & 0555) | S_IFDIR;
1521 break;
1522 case Opt_fmode:
1523 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1524 break;
1525 case Opt_mode:
1526 data->root_mode = (result.uint_32 & 0555) | S_IFDIR;
1527 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1528 break;
1529
1530 case Opt_uid:
1531 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1532 if (!uid_valid(data->perms.uid))
1533 goto unmapped_value;
1534 break;
1535 case Opt_gid:
1536 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1537 if (!gid_valid(data->perms.gid))
1538 goto unmapped_value;
1539 break;
1540
1541 default:
1542 return -ENOPARAM;
1543 }
1544
1545 return 0;
1546
1547 unmapped_value:
1548 return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1549 }
1550
1551 /*
1552 * Set up the superblock for a mount.
1553 */
1554 static int ffs_fs_get_tree(struct fs_context *fc)
1555 {
1556 struct ffs_sb_fill_data *ctx = fc->fs_private;
1557 void *ffs_dev;
1558 struct ffs_data *ffs;
1559
1560 ENTER();
1561
1562 if (!fc->source)
1563 return invalf(fc, "No source specified");
1564
1565 ffs = ffs_data_new(fc->source);
1566 if (!ffs)
1567 return -ENOMEM;
1568 ffs->file_perms = ctx->perms;
1569 ffs->no_disconnect = ctx->no_disconnect;
1570
1571 ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1572 if (!ffs->dev_name) {
1573 ffs_data_put(ffs);
1574 return -ENOMEM;
1575 }
1576
1577 ffs_dev = ffs_acquire_dev(ffs->dev_name);
1578 if (IS_ERR(ffs_dev)) {
1579 ffs_data_put(ffs);
1580 return PTR_ERR(ffs_dev);
1581 }
1582
1583 ffs->private_data = ffs_dev;
1584 ctx->ffs_data = ffs;
1585 return get_tree_nodev(fc, ffs_sb_fill);
1586 }
1587
1588 static void ffs_fs_free_fc(struct fs_context *fc)
1589 {
1590 struct ffs_sb_fill_data *ctx = fc->fs_private;
1591
1592 if (ctx) {
1593 if (ctx->ffs_data) {
1594 ffs_release_dev(ctx->ffs_data);
1595 ffs_data_put(ctx->ffs_data);
1596 }
1597
1598 kfree(ctx);
1599 }
1600 }
1601
1602 static const struct fs_context_operations ffs_fs_context_ops = {
1603 .free = ffs_fs_free_fc,
1604 .parse_param = ffs_fs_parse_param,
1605 .get_tree = ffs_fs_get_tree,
1606 };
1607
1608 static int ffs_fs_init_fs_context(struct fs_context *fc)
1609 {
1610 struct ffs_sb_fill_data *ctx;
1611
1612 ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1613 if (!ctx)
1614 return -ENOMEM;
1615
1616 ctx->perms.mode = S_IFREG | 0600;
1617 ctx->perms.uid = GLOBAL_ROOT_UID;
1618 ctx->perms.gid = GLOBAL_ROOT_GID;
1619 ctx->root_mode = S_IFDIR | 0500;
1620 ctx->no_disconnect = false;
1621
1622 fc->fs_private = ctx;
1623 fc->ops = &ffs_fs_context_ops;
1624 return 0;
1625 }
1626
1627 static void
1628 ffs_fs_kill_sb(struct super_block *sb)
1629 {
1630 ENTER();
1631
1632 kill_litter_super(sb);
1633 if (sb->s_fs_info) {
1634 ffs_release_dev(sb->s_fs_info);
1635 ffs_data_closed(sb->s_fs_info);
1636 }
1637 }
1638
1639 static struct file_system_type ffs_fs_type = {
1640 .owner = THIS_MODULE,
1641 .name = "functionfs",
1642 .init_fs_context = ffs_fs_init_fs_context,
1643 .parameters = ffs_fs_fs_parameters,
1644 .kill_sb = ffs_fs_kill_sb,
1645 };
1646 MODULE_ALIAS_FS("functionfs");
1647
1648
1649 /* Driver's main init/cleanup functions *************************************/
1650
1651 static int functionfs_init(void)
1652 {
1653 int ret;
1654
1655 ENTER();
1656
1657 ret = register_filesystem(&ffs_fs_type);
1658 if (!ret)
1659 pr_info("file system registered\n");
1660 else
1661 pr_err("failed registering file system (%d)\n", ret);
1662
1663 return ret;
1664 }
1665
1666 static void functionfs_cleanup(void)
1667 {
1668 ENTER();
1669
1670 pr_info("unloading\n");
1671 unregister_filesystem(&ffs_fs_type);
1672 }
1673
1674
1675 /* ffs_data and ffs_function construction and destruction code **************/
1676
1677 static void ffs_data_clear(struct ffs_data *ffs);
1678 static void ffs_data_reset(struct ffs_data *ffs);
1679
1680 static void ffs_data_get(struct ffs_data *ffs)
1681 {
1682 ENTER();
1683
1684 refcount_inc(&ffs->ref);
1685 }
1686
1687 static void ffs_data_opened(struct ffs_data *ffs)
1688 {
1689 ENTER();
1690
1691 refcount_inc(&ffs->ref);
1692 if (atomic_add_return(1, &ffs->opened) == 1 &&
1693 ffs->state == FFS_DEACTIVATED) {
1694 ffs->state = FFS_CLOSING;
1695 ffs_data_reset(ffs);
1696 }
1697 }
1698
1699 static void ffs_data_put(struct ffs_data *ffs)
1700 {
1701 ENTER();
1702
1703 if (refcount_dec_and_test(&ffs->ref)) {
1704 pr_info("%s(): freeing\n", __func__);
1705 ffs_data_clear(ffs);
1706 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1707 swait_active(&ffs->ep0req_completion.wait) ||
1708 waitqueue_active(&ffs->wait));
1709 destroy_workqueue(ffs->io_completion_wq);
1710 kfree(ffs->dev_name);
1711 kfree(ffs);
1712 }
1713 }
1714
1715 static void ffs_data_closed(struct ffs_data *ffs)
1716 {
1717 ENTER();
1718
1719 if (atomic_dec_and_test(&ffs->opened)) {
1720 if (ffs->no_disconnect) {
1721 ffs->state = FFS_DEACTIVATED;
1722 if (ffs->epfiles) {
1723 ffs_epfiles_destroy(ffs->epfiles,
1724 ffs->eps_count);
1725 ffs->epfiles = NULL;
1726 }
1727 if (ffs->setup_state == FFS_SETUP_PENDING)
1728 __ffs_ep0_stall(ffs);
1729 } else {
1730 ffs->state = FFS_CLOSING;
1731 ffs_data_reset(ffs);
1732 }
1733 }
1734 if (atomic_read(&ffs->opened) < 0) {
1735 ffs->state = FFS_CLOSING;
1736 ffs_data_reset(ffs);
1737 }
1738
1739 ffs_data_put(ffs);
1740 }
1741
1742 static struct ffs_data *ffs_data_new(const char *dev_name)
1743 {
1744 struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1745 if (!ffs)
1746 return NULL;
1747
1748 ENTER();
1749
1750 ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1751 if (!ffs->io_completion_wq) {
1752 kfree(ffs);
1753 return NULL;
1754 }
1755
1756 refcount_set(&ffs->ref, 1);
1757 atomic_set(&ffs->opened, 0);
1758 ffs->state = FFS_READ_DESCRIPTORS;
1759 mutex_init(&ffs->mutex);
1760 spin_lock_init(&ffs->eps_lock);
1761 init_waitqueue_head(&ffs->ev.waitq);
1762 init_waitqueue_head(&ffs->wait);
1763 init_completion(&ffs->ep0req_completion);
1764
1765 /* XXX REVISIT need to update it in some places, or do we? */
1766 ffs->ev.can_stall = 1;
1767
1768 return ffs;
1769 }
1770
1771 static void ffs_data_clear(struct ffs_data *ffs)
1772 {
1773 ENTER();
1774
1775 ffs_closed(ffs);
1776
1777 BUG_ON(ffs->gadget);
1778
1779 if (ffs->epfiles)
1780 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1781
1782 if (ffs->ffs_eventfd)
1783 eventfd_ctx_put(ffs->ffs_eventfd);
1784
1785 kfree(ffs->raw_descs_data);
1786 kfree(ffs->raw_strings);
1787 kfree(ffs->stringtabs);
1788 }
1789
1790 static void ffs_data_reset(struct ffs_data *ffs)
1791 {
1792 ENTER();
1793
1794 ffs_data_clear(ffs);
1795
1796 ffs->epfiles = NULL;
1797 ffs->raw_descs_data = NULL;
1798 ffs->raw_descs = NULL;
1799 ffs->raw_strings = NULL;
1800 ffs->stringtabs = NULL;
1801
1802 ffs->raw_descs_length = 0;
1803 ffs->fs_descs_count = 0;
1804 ffs->hs_descs_count = 0;
1805 ffs->ss_descs_count = 0;
1806
1807 ffs->strings_count = 0;
1808 ffs->interfaces_count = 0;
1809 ffs->eps_count = 0;
1810
1811 ffs->ev.count = 0;
1812
1813 ffs->state = FFS_READ_DESCRIPTORS;
1814 ffs->setup_state = FFS_NO_SETUP;
1815 ffs->flags = 0;
1816
1817 ffs->ms_os_descs_ext_prop_count = 0;
1818 ffs->ms_os_descs_ext_prop_name_len = 0;
1819 ffs->ms_os_descs_ext_prop_data_len = 0;
1820 }
1821
1822
1823 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1824 {
1825 struct usb_gadget_strings **lang;
1826 int first_id;
1827
1828 ENTER();
1829
1830 if (WARN_ON(ffs->state != FFS_ACTIVE
1831 || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1832 return -EBADFD;
1833
1834 first_id = usb_string_ids_n(cdev, ffs->strings_count);
1835 if (first_id < 0)
1836 return first_id;
1837
1838 ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1839 if (!ffs->ep0req)
1840 return -ENOMEM;
1841 ffs->ep0req->complete = ffs_ep0_complete;
1842 ffs->ep0req->context = ffs;
1843
1844 lang = ffs->stringtabs;
1845 if (lang) {
1846 for (; *lang; ++lang) {
1847 struct usb_string *str = (*lang)->strings;
1848 int id = first_id;
1849 for (; str->s; ++id, ++str)
1850 str->id = id;
1851 }
1852 }
1853
1854 ffs->gadget = cdev->gadget;
1855 ffs_data_get(ffs);
1856 return 0;
1857 }
1858
1859 static void functionfs_unbind(struct ffs_data *ffs)
1860 {
1861 ENTER();
1862
1863 if (!WARN_ON(!ffs->gadget)) {
1864 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1865 ffs->ep0req = NULL;
1866 ffs->gadget = NULL;
1867 clear_bit(FFS_FL_BOUND, &ffs->flags);
1868 ffs_data_put(ffs);
1869 }
1870 }
1871
1872 static int ffs_epfiles_create(struct ffs_data *ffs)
1873 {
1874 struct ffs_epfile *epfile, *epfiles;
1875 unsigned i, count;
1876
1877 ENTER();
1878
1879 count = ffs->eps_count;
1880 epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1881 if (!epfiles)
1882 return -ENOMEM;
1883
1884 epfile = epfiles;
1885 for (i = 1; i <= count; ++i, ++epfile) {
1886 epfile->ffs = ffs;
1887 mutex_init(&epfile->mutex);
1888 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1889 sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1890 else
1891 sprintf(epfile->name, "ep%u", i);
1892 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1893 epfile,
1894 &ffs_epfile_operations);
1895 if (!epfile->dentry) {
1896 ffs_epfiles_destroy(epfiles, i - 1);
1897 return -ENOMEM;
1898 }
1899 }
1900
1901 ffs->epfiles = epfiles;
1902 return 0;
1903 }
1904
1905 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1906 {
1907 struct ffs_epfile *epfile = epfiles;
1908
1909 ENTER();
1910
1911 for (; count; --count, ++epfile) {
1912 BUG_ON(mutex_is_locked(&epfile->mutex));
1913 if (epfile->dentry) {
1914 d_delete(epfile->dentry);
1915 dput(epfile->dentry);
1916 epfile->dentry = NULL;
1917 }
1918 }
1919
1920 kfree(epfiles);
1921 }
1922
1923 static void ffs_func_eps_disable(struct ffs_function *func)
1924 {
1925 struct ffs_ep *ep = func->eps;
1926 struct ffs_epfile *epfile = func->ffs->epfiles;
1927 unsigned count = func->ffs->eps_count;
1928 unsigned long flags;
1929
1930 spin_lock_irqsave(&func->ffs->eps_lock, flags);
1931 while (count--) {
1932 /* pending requests get nuked */
1933 if (ep->ep)
1934 usb_ep_disable(ep->ep);
1935 ++ep;
1936
1937 if (epfile) {
1938 epfile->ep = NULL;
1939 __ffs_epfile_read_buffer_free(epfile);
1940 ++epfile;
1941 }
1942 }
1943 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1944 }
1945
1946 static int ffs_func_eps_enable(struct ffs_function *func)
1947 {
1948 struct ffs_data *ffs = func->ffs;
1949 struct ffs_ep *ep = func->eps;
1950 struct ffs_epfile *epfile = ffs->epfiles;
1951 unsigned count = ffs->eps_count;
1952 unsigned long flags;
1953 int ret = 0;
1954
1955 spin_lock_irqsave(&func->ffs->eps_lock, flags);
1956 while(count--) {
1957 ep->ep->driver_data = ep;
1958
1959 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1960 if (ret) {
1961 pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1962 __func__, ep->ep->name, ret);
1963 break;
1964 }
1965
1966 ret = usb_ep_enable(ep->ep);
1967 if (!ret) {
1968 epfile->ep = ep;
1969 epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1970 epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1971 } else {
1972 break;
1973 }
1974
1975 ++ep;
1976 ++epfile;
1977 }
1978
1979 wake_up_interruptible(&ffs->wait);
1980 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1981
1982 return ret;
1983 }
1984
1985
1986 /* Parsing and building descriptors and strings *****************************/
1987
1988 /*
1989 * This validates if data pointed by data is a valid USB descriptor as
1990 * well as record how many interfaces, endpoints and strings are
1991 * required by given configuration. Returns address after the
1992 * descriptor or NULL if data is invalid.
1993 */
1994
1995 enum ffs_entity_type {
1996 FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1997 };
1998
1999 enum ffs_os_desc_type {
2000 FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
2001 };
2002
2003 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2004 u8 *valuep,
2005 struct usb_descriptor_header *desc,
2006 void *priv);
2007
2008 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2009 struct usb_os_desc_header *h, void *data,
2010 unsigned len, void *priv);
2011
2012 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2013 ffs_entity_callback entity,
2014 void *priv, int *current_class)
2015 {
2016 struct usb_descriptor_header *_ds = (void *)data;
2017 u8 length;
2018 int ret;
2019
2020 ENTER();
2021
2022 /* At least two bytes are required: length and type */
2023 if (len < 2) {
2024 pr_vdebug("descriptor too short\n");
2025 return -EINVAL;
2026 }
2027
2028 /* If we have at least as many bytes as the descriptor takes? */
2029 length = _ds->bLength;
2030 if (len < length) {
2031 pr_vdebug("descriptor longer then available data\n");
2032 return -EINVAL;
2033 }
2034
2035 #define __entity_check_INTERFACE(val) 1
2036 #define __entity_check_STRING(val) (val)
2037 #define __entity_check_ENDPOINT(val) ((val) & USB_ENDPOINT_NUMBER_MASK)
2038 #define __entity(type, val) do { \
2039 pr_vdebug("entity " #type "(%02x)\n", (val)); \
2040 if (!__entity_check_ ##type(val)) { \
2041 pr_vdebug("invalid entity's value\n"); \
2042 return -EINVAL; \
2043 } \
2044 ret = entity(FFS_ ##type, &val, _ds, priv); \
2045 if (ret < 0) { \
2046 pr_debug("entity " #type "(%02x); ret = %d\n", \
2047 (val), ret); \
2048 return ret; \
2049 } \
2050 } while (0)
2051
2052 /* Parse descriptor depending on type. */
2053 switch (_ds->bDescriptorType) {
2054 case USB_DT_DEVICE:
2055 case USB_DT_CONFIG:
2056 case USB_DT_STRING:
2057 case USB_DT_DEVICE_QUALIFIER:
2058 /* function can't have any of those */
2059 pr_vdebug("descriptor reserved for gadget: %d\n",
2060 _ds->bDescriptorType);
2061 return -EINVAL;
2062
2063 case USB_DT_INTERFACE: {
2064 struct usb_interface_descriptor *ds = (void *)_ds;
2065 pr_vdebug("interface descriptor\n");
2066 if (length != sizeof *ds)
2067 goto inv_length;
2068
2069 __entity(INTERFACE, ds->bInterfaceNumber);
2070 if (ds->iInterface)
2071 __entity(STRING, ds->iInterface);
2072 *current_class = ds->bInterfaceClass;
2073 }
2074 break;
2075
2076 case USB_DT_ENDPOINT: {
2077 struct usb_endpoint_descriptor *ds = (void *)_ds;
2078 pr_vdebug("endpoint descriptor\n");
2079 if (length != USB_DT_ENDPOINT_SIZE &&
2080 length != USB_DT_ENDPOINT_AUDIO_SIZE)
2081 goto inv_length;
2082 __entity(ENDPOINT, ds->bEndpointAddress);
2083 }
2084 break;
2085
2086 case USB_TYPE_CLASS | 0x01:
2087 if (*current_class == USB_INTERFACE_CLASS_HID) {
2088 pr_vdebug("hid descriptor\n");
2089 if (length != sizeof(struct hid_descriptor))
2090 goto inv_length;
2091 break;
2092 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2093 pr_vdebug("ccid descriptor\n");
2094 if (length != sizeof(struct ccid_descriptor))
2095 goto inv_length;
2096 break;
2097 } else {
2098 pr_vdebug("unknown descriptor: %d for class %d\n",
2099 _ds->bDescriptorType, *current_class);
2100 return -EINVAL;
2101 }
2102
2103 case USB_DT_OTG:
2104 if (length != sizeof(struct usb_otg_descriptor))
2105 goto inv_length;
2106 break;
2107
2108 case USB_DT_INTERFACE_ASSOCIATION: {
2109 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2110 pr_vdebug("interface association descriptor\n");
2111 if (length != sizeof *ds)
2112 goto inv_length;
2113 if (ds->iFunction)
2114 __entity(STRING, ds->iFunction);
2115 }
2116 break;
2117
2118 case USB_DT_SS_ENDPOINT_COMP:
2119 pr_vdebug("EP SS companion descriptor\n");
2120 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2121 goto inv_length;
2122 break;
2123
2124 case USB_DT_OTHER_SPEED_CONFIG:
2125 case USB_DT_INTERFACE_POWER:
2126 case USB_DT_DEBUG:
2127 case USB_DT_SECURITY:
2128 case USB_DT_CS_RADIO_CONTROL:
2129 /* TODO */
2130 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2131 return -EINVAL;
2132
2133 default:
2134 /* We should never be here */
2135 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2136 return -EINVAL;
2137
2138 inv_length:
2139 pr_vdebug("invalid length: %d (descriptor %d)\n",
2140 _ds->bLength, _ds->bDescriptorType);
2141 return -EINVAL;
2142 }
2143
2144 #undef __entity
2145 #undef __entity_check_DESCRIPTOR
2146 #undef __entity_check_INTERFACE
2147 #undef __entity_check_STRING
2148 #undef __entity_check_ENDPOINT
2149
2150 return length;
2151 }
2152
2153 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2154 ffs_entity_callback entity, void *priv)
2155 {
2156 const unsigned _len = len;
2157 unsigned long num = 0;
2158 int current_class = -1;
2159
2160 ENTER();
2161
2162 for (;;) {
2163 int ret;
2164
2165 if (num == count)
2166 data = NULL;
2167
2168 /* Record "descriptor" entity */
2169 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2170 if (ret < 0) {
2171 pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2172 num, ret);
2173 return ret;
2174 }
2175
2176 if (!data)
2177 return _len - len;
2178
2179 ret = ffs_do_single_desc(data, len, entity, priv,
2180 &current_class);
2181 if (ret < 0) {
2182 pr_debug("%s returns %d\n", __func__, ret);
2183 return ret;
2184 }
2185
2186 len -= ret;
2187 data += ret;
2188 ++num;
2189 }
2190 }
2191
2192 static int __ffs_data_do_entity(enum ffs_entity_type type,
2193 u8 *valuep, struct usb_descriptor_header *desc,
2194 void *priv)
2195 {
2196 struct ffs_desc_helper *helper = priv;
2197 struct usb_endpoint_descriptor *d;
2198
2199 ENTER();
2200
2201 switch (type) {
2202 case FFS_DESCRIPTOR:
2203 break;
2204
2205 case FFS_INTERFACE:
2206 /*
2207 * Interfaces are indexed from zero so if we
2208 * encountered interface "n" then there are at least
2209 * "n+1" interfaces.
2210 */
2211 if (*valuep >= helper->interfaces_count)
2212 helper->interfaces_count = *valuep + 1;
2213 break;
2214
2215 case FFS_STRING:
2216 /*
2217 * Strings are indexed from 1 (0 is reserved
2218 * for languages list)
2219 */
2220 if (*valuep > helper->ffs->strings_count)
2221 helper->ffs->strings_count = *valuep;
2222 break;
2223
2224 case FFS_ENDPOINT:
2225 d = (void *)desc;
2226 helper->eps_count++;
2227 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2228 return -EINVAL;
2229 /* Check if descriptors for any speed were already parsed */
2230 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2231 helper->ffs->eps_addrmap[helper->eps_count] =
2232 d->bEndpointAddress;
2233 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2234 d->bEndpointAddress)
2235 return -EINVAL;
2236 break;
2237 }
2238
2239 return 0;
2240 }
2241
2242 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2243 struct usb_os_desc_header *desc)
2244 {
2245 u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2246 u16 w_index = le16_to_cpu(desc->wIndex);
2247
2248 if (bcd_version != 1) {
2249 pr_vdebug("unsupported os descriptors version: %d",
2250 bcd_version);
2251 return -EINVAL;
2252 }
2253 switch (w_index) {
2254 case 0x4:
2255 *next_type = FFS_OS_DESC_EXT_COMPAT;
2256 break;
2257 case 0x5:
2258 *next_type = FFS_OS_DESC_EXT_PROP;
2259 break;
2260 default:
2261 pr_vdebug("unsupported os descriptor type: %d", w_index);
2262 return -EINVAL;
2263 }
2264
2265 return sizeof(*desc);
2266 }
2267
2268 /*
2269 * Process all extended compatibility/extended property descriptors
2270 * of a feature descriptor
2271 */
2272 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2273 enum ffs_os_desc_type type,
2274 u16 feature_count,
2275 ffs_os_desc_callback entity,
2276 void *priv,
2277 struct usb_os_desc_header *h)
2278 {
2279 int ret;
2280 const unsigned _len = len;
2281
2282 ENTER();
2283
2284 /* loop over all ext compat/ext prop descriptors */
2285 while (feature_count--) {
2286 ret = entity(type, h, data, len, priv);
2287 if (ret < 0) {
2288 pr_debug("bad OS descriptor, type: %d\n", type);
2289 return ret;
2290 }
2291 data += ret;
2292 len -= ret;
2293 }
2294 return _len - len;
2295 }
2296
2297 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2298 static int __must_check ffs_do_os_descs(unsigned count,
2299 char *data, unsigned len,
2300 ffs_os_desc_callback entity, void *priv)
2301 {
2302 const unsigned _len = len;
2303 unsigned long num = 0;
2304
2305 ENTER();
2306
2307 for (num = 0; num < count; ++num) {
2308 int ret;
2309 enum ffs_os_desc_type type;
2310 u16 feature_count;
2311 struct usb_os_desc_header *desc = (void *)data;
2312
2313 if (len < sizeof(*desc))
2314 return -EINVAL;
2315
2316 /*
2317 * Record "descriptor" entity.
2318 * Process dwLength, bcdVersion, wIndex, get b/wCount.
2319 * Move the data pointer to the beginning of extended
2320 * compatibilities proper or extended properties proper
2321 * portions of the data
2322 */
2323 if (le32_to_cpu(desc->dwLength) > len)
2324 return -EINVAL;
2325
2326 ret = __ffs_do_os_desc_header(&type, desc);
2327 if (ret < 0) {
2328 pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2329 num, ret);
2330 return ret;
2331 }
2332 /*
2333 * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2334 */
2335 feature_count = le16_to_cpu(desc->wCount);
2336 if (type == FFS_OS_DESC_EXT_COMPAT &&
2337 (feature_count > 255 || desc->Reserved))
2338 return -EINVAL;
2339 len -= ret;
2340 data += ret;
2341
2342 /*
2343 * Process all function/property descriptors
2344 * of this Feature Descriptor
2345 */
2346 ret = ffs_do_single_os_desc(data, len, type,
2347 feature_count, entity, priv, desc);
2348 if (ret < 0) {
2349 pr_debug("%s returns %d\n", __func__, ret);
2350 return ret;
2351 }
2352
2353 len -= ret;
2354 data += ret;
2355 }
2356 return _len - len;
2357 }
2358
2359 /*
2360 * Validate contents of the buffer from userspace related to OS descriptors.
2361 */
2362 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2363 struct usb_os_desc_header *h, void *data,
2364 unsigned len, void *priv)
2365 {
2366 struct ffs_data *ffs = priv;
2367 u8 length;
2368
2369 ENTER();
2370
2371 switch (type) {
2372 case FFS_OS_DESC_EXT_COMPAT: {
2373 struct usb_ext_compat_desc *d = data;
2374 int i;
2375
2376 if (len < sizeof(*d) ||
2377 d->bFirstInterfaceNumber >= ffs->interfaces_count)
2378 return -EINVAL;
2379 if (d->Reserved1 != 1) {
2380 /*
2381 * According to the spec, Reserved1 must be set to 1
2382 * but older kernels incorrectly rejected non-zero
2383 * values. We fix it here to avoid returning EINVAL
2384 * in response to values we used to accept.
2385 */
2386 pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2387 d->Reserved1 = 1;
2388 }
2389 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2390 if (d->Reserved2[i])
2391 return -EINVAL;
2392
2393 length = sizeof(struct usb_ext_compat_desc);
2394 }
2395 break;
2396 case FFS_OS_DESC_EXT_PROP: {
2397 struct usb_ext_prop_desc *d = data;
2398 u32 type, pdl;
2399 u16 pnl;
2400
2401 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2402 return -EINVAL;
2403 length = le32_to_cpu(d->dwSize);
2404 if (len < length)
2405 return -EINVAL;
2406 type = le32_to_cpu(d->dwPropertyDataType);
2407 if (type < USB_EXT_PROP_UNICODE ||
2408 type > USB_EXT_PROP_UNICODE_MULTI) {
2409 pr_vdebug("unsupported os descriptor property type: %d",
2410 type);
2411 return -EINVAL;
2412 }
2413 pnl = le16_to_cpu(d->wPropertyNameLength);
2414 if (length < 14 + pnl) {
2415 pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2416 length, pnl, type);
2417 return -EINVAL;
2418 }
2419 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2420 if (length != 14 + pnl + pdl) {
2421 pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2422 length, pnl, pdl, type);
2423 return -EINVAL;
2424 }
2425 ++ffs->ms_os_descs_ext_prop_count;
2426 /* property name reported to the host as "WCHAR"s */
2427 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2428 ffs->ms_os_descs_ext_prop_data_len += pdl;
2429 }
2430 break;
2431 default:
2432 pr_vdebug("unknown descriptor: %d\n", type);
2433 return -EINVAL;
2434 }
2435 return length;
2436 }
2437
2438 static int __ffs_data_got_descs(struct ffs_data *ffs,
2439 char *const _data, size_t len)
2440 {
2441 char *data = _data, *raw_descs;
2442 unsigned os_descs_count = 0, counts[3], flags;
2443 int ret = -EINVAL, i;
2444 struct ffs_desc_helper helper;
2445
2446 ENTER();
2447
2448 if (get_unaligned_le32(data + 4) != len)
2449 goto error;
2450
2451 switch (get_unaligned_le32(data)) {
2452 case FUNCTIONFS_DESCRIPTORS_MAGIC:
2453 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2454 data += 8;
2455 len -= 8;
2456 break;
2457 case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2458 flags = get_unaligned_le32(data + 8);
2459 ffs->user_flags = flags;
2460 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2461 FUNCTIONFS_HAS_HS_DESC |
2462 FUNCTIONFS_HAS_SS_DESC |
2463 FUNCTIONFS_HAS_MS_OS_DESC |
2464 FUNCTIONFS_VIRTUAL_ADDR |
2465 FUNCTIONFS_EVENTFD |
2466 FUNCTIONFS_ALL_CTRL_RECIP |
2467 FUNCTIONFS_CONFIG0_SETUP)) {
2468 ret = -ENOSYS;
2469 goto error;
2470 }
2471 data += 12;
2472 len -= 12;
2473 break;
2474 default:
2475 goto error;
2476 }
2477
2478 if (flags & FUNCTIONFS_EVENTFD) {
2479 if (len < 4)
2480 goto error;
2481 ffs->ffs_eventfd =
2482 eventfd_ctx_fdget((int)get_unaligned_le32(data));
2483 if (IS_ERR(ffs->ffs_eventfd)) {
2484 ret = PTR_ERR(ffs->ffs_eventfd);
2485 ffs->ffs_eventfd = NULL;
2486 goto error;
2487 }
2488 data += 4;
2489 len -= 4;
2490 }
2491
2492 /* Read fs_count, hs_count and ss_count (if present) */
2493 for (i = 0; i < 3; ++i) {
2494 if (!(flags & (1 << i))) {
2495 counts[i] = 0;
2496 } else if (len < 4) {
2497 goto error;
2498 } else {
2499 counts[i] = get_unaligned_le32(data);
2500 data += 4;
2501 len -= 4;
2502 }
2503 }
2504 if (flags & (1 << i)) {
2505 if (len < 4) {
2506 goto error;
2507 }
2508 os_descs_count = get_unaligned_le32(data);
2509 data += 4;
2510 len -= 4;
2511 }
2512
2513 /* Read descriptors */
2514 raw_descs = data;
2515 helper.ffs = ffs;
2516 for (i = 0; i < 3; ++i) {
2517 if (!counts[i])
2518 continue;
2519 helper.interfaces_count = 0;
2520 helper.eps_count = 0;
2521 ret = ffs_do_descs(counts[i], data, len,
2522 __ffs_data_do_entity, &helper);
2523 if (ret < 0)
2524 goto error;
2525 if (!ffs->eps_count && !ffs->interfaces_count) {
2526 ffs->eps_count = helper.eps_count;
2527 ffs->interfaces_count = helper.interfaces_count;
2528 } else {
2529 if (ffs->eps_count != helper.eps_count) {
2530 ret = -EINVAL;
2531 goto error;
2532 }
2533 if (ffs->interfaces_count != helper.interfaces_count) {
2534 ret = -EINVAL;
2535 goto error;
2536 }
2537 }
2538 data += ret;
2539 len -= ret;
2540 }
2541 if (os_descs_count) {
2542 ret = ffs_do_os_descs(os_descs_count, data, len,
2543 __ffs_data_do_os_desc, ffs);
2544 if (ret < 0)
2545 goto error;
2546 data += ret;
2547 len -= ret;
2548 }
2549
2550 if (raw_descs == data || len) {
2551 ret = -EINVAL;
2552 goto error;
2553 }
2554
2555 ffs->raw_descs_data = _data;
2556 ffs->raw_descs = raw_descs;
2557 ffs->raw_descs_length = data - raw_descs;
2558 ffs->fs_descs_count = counts[0];
2559 ffs->hs_descs_count = counts[1];
2560 ffs->ss_descs_count = counts[2];
2561 ffs->ms_os_descs_count = os_descs_count;
2562
2563 return 0;
2564
2565 error:
2566 kfree(_data);
2567 return ret;
2568 }
2569
2570 static int __ffs_data_got_strings(struct ffs_data *ffs,
2571 char *const _data, size_t len)
2572 {
2573 u32 str_count, needed_count, lang_count;
2574 struct usb_gadget_strings **stringtabs, *t;
2575 const char *data = _data;
2576 struct usb_string *s;
2577
2578 ENTER();
2579
2580 if (len < 16 ||
2581 get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2582 get_unaligned_le32(data + 4) != len)
2583 goto error;
2584 str_count = get_unaligned_le32(data + 8);
2585 lang_count = get_unaligned_le32(data + 12);
2586
2587 /* if one is zero the other must be zero */
2588 if (!str_count != !lang_count)
2589 goto error;
2590
2591 /* Do we have at least as many strings as descriptors need? */
2592 needed_count = ffs->strings_count;
2593 if (str_count < needed_count)
2594 goto error;
2595
2596 /*
2597 * If we don't need any strings just return and free all
2598 * memory.
2599 */
2600 if (!needed_count) {
2601 kfree(_data);
2602 return 0;
2603 }
2604
2605 /* Allocate everything in one chunk so there's less maintenance. */
2606 {
2607 unsigned i = 0;
2608 vla_group(d);
2609 vla_item(d, struct usb_gadget_strings *, stringtabs,
2610 lang_count + 1);
2611 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2612 vla_item(d, struct usb_string, strings,
2613 lang_count*(needed_count+1));
2614
2615 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2616
2617 if (!vlabuf) {
2618 kfree(_data);
2619 return -ENOMEM;
2620 }
2621
2622 /* Initialize the VLA pointers */
2623 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2624 t = vla_ptr(vlabuf, d, stringtab);
2625 i = lang_count;
2626 do {
2627 *stringtabs++ = t++;
2628 } while (--i);
2629 *stringtabs = NULL;
2630
2631 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2632 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2633 t = vla_ptr(vlabuf, d, stringtab);
2634 s = vla_ptr(vlabuf, d, strings);
2635 }
2636
2637 /* For each language */
2638 data += 16;
2639 len -= 16;
2640
2641 do { /* lang_count > 0 so we can use do-while */
2642 unsigned needed = needed_count;
2643
2644 if (len < 3)
2645 goto error_free;
2646 t->language = get_unaligned_le16(data);
2647 t->strings = s;
2648 ++t;
2649
2650 data += 2;
2651 len -= 2;
2652
2653 /* For each string */
2654 do { /* str_count > 0 so we can use do-while */
2655 size_t length = strnlen(data, len);
2656
2657 if (length == len)
2658 goto error_free;
2659
2660 /*
2661 * User may provide more strings then we need,
2662 * if that's the case we simply ignore the
2663 * rest
2664 */
2665 if (needed) {
2666 /*
2667 * s->id will be set while adding
2668 * function to configuration so for
2669 * now just leave garbage here.
2670 */
2671 s->s = data;
2672 --needed;
2673 ++s;
2674 }
2675
2676 data += length + 1;
2677 len -= length + 1;
2678 } while (--str_count);
2679
2680 s->id = 0; /* terminator */
2681 s->s = NULL;
2682 ++s;
2683
2684 } while (--lang_count);
2685
2686 /* Some garbage left? */
2687 if (len)
2688 goto error_free;
2689
2690 /* Done! */
2691 ffs->stringtabs = stringtabs;
2692 ffs->raw_strings = _data;
2693
2694 return 0;
2695
2696 error_free:
2697 kfree(stringtabs);
2698 error:
2699 kfree(_data);
2700 return -EINVAL;
2701 }
2702
2703
2704 /* Events handling and management *******************************************/
2705
2706 static void __ffs_event_add(struct ffs_data *ffs,
2707 enum usb_functionfs_event_type type)
2708 {
2709 enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2710 int neg = 0;
2711
2712 /*
2713 * Abort any unhandled setup
2714 *
2715 * We do not need to worry about some cmpxchg() changing value
2716 * of ffs->setup_state without holding the lock because when
2717 * state is FFS_SETUP_PENDING cmpxchg() in several places in
2718 * the source does nothing.
2719 */
2720 if (ffs->setup_state == FFS_SETUP_PENDING)
2721 ffs->setup_state = FFS_SETUP_CANCELLED;
2722
2723 /*
2724 * Logic of this function guarantees that there are at most four pending
2725 * evens on ffs->ev.types queue. This is important because the queue
2726 * has space for four elements only and __ffs_ep0_read_events function
2727 * depends on that limit as well. If more event types are added, those
2728 * limits have to be revisited or guaranteed to still hold.
2729 */
2730 switch (type) {
2731 case FUNCTIONFS_RESUME:
2732 rem_type2 = FUNCTIONFS_SUSPEND;
2733 fallthrough;
2734 case FUNCTIONFS_SUSPEND:
2735 case FUNCTIONFS_SETUP:
2736 rem_type1 = type;
2737 /* Discard all similar events */
2738 break;
2739
2740 case FUNCTIONFS_BIND:
2741 case FUNCTIONFS_UNBIND:
2742 case FUNCTIONFS_DISABLE:
2743 case FUNCTIONFS_ENABLE:
2744 /* Discard everything other then power management. */
2745 rem_type1 = FUNCTIONFS_SUSPEND;
2746 rem_type2 = FUNCTIONFS_RESUME;
2747 neg = 1;
2748 break;
2749
2750 default:
2751 WARN(1, "%d: unknown event, this should not happen\n", type);
2752 return;
2753 }
2754
2755 {
2756 u8 *ev = ffs->ev.types, *out = ev;
2757 unsigned n = ffs->ev.count;
2758 for (; n; --n, ++ev)
2759 if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2760 *out++ = *ev;
2761 else
2762 pr_vdebug("purging event %d\n", *ev);
2763 ffs->ev.count = out - ffs->ev.types;
2764 }
2765
2766 pr_vdebug("adding event %d\n", type);
2767 ffs->ev.types[ffs->ev.count++] = type;
2768 wake_up_locked(&ffs->ev.waitq);
2769 if (ffs->ffs_eventfd)
2770 eventfd_signal(ffs->ffs_eventfd, 1);
2771 }
2772
2773 static void ffs_event_add(struct ffs_data *ffs,
2774 enum usb_functionfs_event_type type)
2775 {
2776 unsigned long flags;
2777 spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2778 __ffs_event_add(ffs, type);
2779 spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2780 }
2781
2782 /* Bind/unbind USB function hooks *******************************************/
2783
2784 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2785 {
2786 int i;
2787
2788 for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2789 if (ffs->eps_addrmap[i] == endpoint_address)
2790 return i;
2791 return -ENOENT;
2792 }
2793
2794 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2795 struct usb_descriptor_header *desc,
2796 void *priv)
2797 {
2798 struct usb_endpoint_descriptor *ds = (void *)desc;
2799 struct ffs_function *func = priv;
2800 struct ffs_ep *ffs_ep;
2801 unsigned ep_desc_id;
2802 int idx;
2803 static const char *speed_names[] = { "full", "high", "super" };
2804
2805 if (type != FFS_DESCRIPTOR)
2806 return 0;
2807
2808 /*
2809 * If ss_descriptors is not NULL, we are reading super speed
2810 * descriptors; if hs_descriptors is not NULL, we are reading high
2811 * speed descriptors; otherwise, we are reading full speed
2812 * descriptors.
2813 */
2814 if (func->function.ss_descriptors) {
2815 ep_desc_id = 2;
2816 func->function.ss_descriptors[(long)valuep] = desc;
2817 } else if (func->function.hs_descriptors) {
2818 ep_desc_id = 1;
2819 func->function.hs_descriptors[(long)valuep] = desc;
2820 } else {
2821 ep_desc_id = 0;
2822 func->function.fs_descriptors[(long)valuep] = desc;
2823 }
2824
2825 if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2826 return 0;
2827
2828 idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2829 if (idx < 0)
2830 return idx;
2831
2832 ffs_ep = func->eps + idx;
2833
2834 if (ffs_ep->descs[ep_desc_id]) {
2835 pr_err("two %sspeed descriptors for EP %d\n",
2836 speed_names[ep_desc_id],
2837 ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2838 return -EINVAL;
2839 }
2840 ffs_ep->descs[ep_desc_id] = ds;
2841
2842 ffs_dump_mem(": Original ep desc", ds, ds->bLength);
2843 if (ffs_ep->ep) {
2844 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2845 if (!ds->wMaxPacketSize)
2846 ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2847 } else {
2848 struct usb_request *req;
2849 struct usb_ep *ep;
2850 u8 bEndpointAddress;
2851 u16 wMaxPacketSize;
2852
2853 /*
2854 * We back up bEndpointAddress because autoconfig overwrites
2855 * it with physical endpoint address.
2856 */
2857 bEndpointAddress = ds->bEndpointAddress;
2858 /*
2859 * We back up wMaxPacketSize because autoconfig treats
2860 * endpoint descriptors as if they were full speed.
2861 */
2862 wMaxPacketSize = ds->wMaxPacketSize;
2863 pr_vdebug("autoconfig\n");
2864 ep = usb_ep_autoconfig(func->gadget, ds);
2865 if (!ep)
2866 return -ENOTSUPP;
2867 ep->driver_data = func->eps + idx;
2868
2869 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2870 if (!req)
2871 return -ENOMEM;
2872
2873 ffs_ep->ep = ep;
2874 ffs_ep->req = req;
2875 func->eps_revmap[ds->bEndpointAddress &
2876 USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2877 /*
2878 * If we use virtual address mapping, we restore
2879 * original bEndpointAddress value.
2880 */
2881 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2882 ds->bEndpointAddress = bEndpointAddress;
2883 /*
2884 * Restore wMaxPacketSize which was potentially
2885 * overwritten by autoconfig.
2886 */
2887 ds->wMaxPacketSize = wMaxPacketSize;
2888 }
2889 ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2890
2891 return 0;
2892 }
2893
2894 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2895 struct usb_descriptor_header *desc,
2896 void *priv)
2897 {
2898 struct ffs_function *func = priv;
2899 unsigned idx;
2900 u8 newValue;
2901
2902 switch (type) {
2903 default:
2904 case FFS_DESCRIPTOR:
2905 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2906 return 0;
2907
2908 case FFS_INTERFACE:
2909 idx = *valuep;
2910 if (func->interfaces_nums[idx] < 0) {
2911 int id = usb_interface_id(func->conf, &func->function);
2912 if (id < 0)
2913 return id;
2914 func->interfaces_nums[idx] = id;
2915 }
2916 newValue = func->interfaces_nums[idx];
2917 break;
2918
2919 case FFS_STRING:
2920 /* String' IDs are allocated when fsf_data is bound to cdev */
2921 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2922 break;
2923
2924 case FFS_ENDPOINT:
2925 /*
2926 * USB_DT_ENDPOINT are handled in
2927 * __ffs_func_bind_do_descs().
2928 */
2929 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2930 return 0;
2931
2932 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2933 if (!func->eps[idx].ep)
2934 return -EINVAL;
2935
2936 {
2937 struct usb_endpoint_descriptor **descs;
2938 descs = func->eps[idx].descs;
2939 newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2940 }
2941 break;
2942 }
2943
2944 pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2945 *valuep = newValue;
2946 return 0;
2947 }
2948
2949 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2950 struct usb_os_desc_header *h, void *data,
2951 unsigned len, void *priv)
2952 {
2953 struct ffs_function *func = priv;
2954 u8 length = 0;
2955
2956 switch (type) {
2957 case FFS_OS_DESC_EXT_COMPAT: {
2958 struct usb_ext_compat_desc *desc = data;
2959 struct usb_os_desc_table *t;
2960
2961 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2962 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2963 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2964 ARRAY_SIZE(desc->CompatibleID) +
2965 ARRAY_SIZE(desc->SubCompatibleID));
2966 length = sizeof(*desc);
2967 }
2968 break;
2969 case FFS_OS_DESC_EXT_PROP: {
2970 struct usb_ext_prop_desc *desc = data;
2971 struct usb_os_desc_table *t;
2972 struct usb_os_desc_ext_prop *ext_prop;
2973 char *ext_prop_name;
2974 char *ext_prop_data;
2975
2976 t = &func->function.os_desc_table[h->interface];
2977 t->if_id = func->interfaces_nums[h->interface];
2978
2979 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2980 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2981
2982 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2983 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2984 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2985 usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2986 length = ext_prop->name_len + ext_prop->data_len + 14;
2987
2988 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2989 func->ffs->ms_os_descs_ext_prop_name_avail +=
2990 ext_prop->name_len;
2991
2992 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2993 func->ffs->ms_os_descs_ext_prop_data_avail +=
2994 ext_prop->data_len;
2995 memcpy(ext_prop_data,
2996 usb_ext_prop_data_ptr(data, ext_prop->name_len),
2997 ext_prop->data_len);
2998 /* unicode data reported to the host as "WCHAR"s */
2999 switch (ext_prop->type) {
3000 case USB_EXT_PROP_UNICODE:
3001 case USB_EXT_PROP_UNICODE_ENV:
3002 case USB_EXT_PROP_UNICODE_LINK:
3003 case USB_EXT_PROP_UNICODE_MULTI:
3004 ext_prop->data_len *= 2;
3005 break;
3006 }
3007 ext_prop->data = ext_prop_data;
3008
3009 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3010 ext_prop->name_len);
3011 /* property name reported to the host as "WCHAR"s */
3012 ext_prop->name_len *= 2;
3013 ext_prop->name = ext_prop_name;
3014
3015 t->os_desc->ext_prop_len +=
3016 ext_prop->name_len + ext_prop->data_len + 14;
3017 ++t->os_desc->ext_prop_count;
3018 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3019 }
3020 break;
3021 default:
3022 pr_vdebug("unknown descriptor: %d\n", type);
3023 }
3024
3025 return length;
3026 }
3027
3028 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3029 struct usb_configuration *c)
3030 {
3031 struct ffs_function *func = ffs_func_from_usb(f);
3032 struct f_fs_opts *ffs_opts =
3033 container_of(f->fi, struct f_fs_opts, func_inst);
3034 int ret;
3035
3036 ENTER();
3037
3038 /*
3039 * Legacy gadget triggers binding in functionfs_ready_callback,
3040 * which already uses locking; taking the same lock here would
3041 * cause a deadlock.
3042 *
3043 * Configfs-enabled gadgets however do need ffs_dev_lock.
3044 */
3045 if (!ffs_opts->no_configfs)
3046 ffs_dev_lock();
3047 ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3048 func->ffs = ffs_opts->dev->ffs_data;
3049 if (!ffs_opts->no_configfs)
3050 ffs_dev_unlock();
3051 if (ret)
3052 return ERR_PTR(ret);
3053
3054 func->conf = c;
3055 func->gadget = c->cdev->gadget;
3056
3057 /*
3058 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3059 * configurations are bound in sequence with list_for_each_entry,
3060 * in each configuration its functions are bound in sequence
3061 * with list_for_each_entry, so we assume no race condition
3062 * with regard to ffs_opts->bound access
3063 */
3064 if (!ffs_opts->refcnt) {
3065 ret = functionfs_bind(func->ffs, c->cdev);
3066 if (ret)
3067 return ERR_PTR(ret);
3068 }
3069 ffs_opts->refcnt++;
3070 func->function.strings = func->ffs->stringtabs;
3071
3072 return ffs_opts;
3073 }
3074
3075 static int _ffs_func_bind(struct usb_configuration *c,
3076 struct usb_function *f)
3077 {
3078 struct ffs_function *func = ffs_func_from_usb(f);
3079 struct ffs_data *ffs = func->ffs;
3080
3081 const int full = !!func->ffs->fs_descs_count;
3082 const int high = !!func->ffs->hs_descs_count;
3083 const int super = !!func->ffs->ss_descs_count;
3084
3085 int fs_len, hs_len, ss_len, ret, i;
3086 struct ffs_ep *eps_ptr;
3087
3088 /* Make it a single chunk, less management later on */
3089 vla_group(d);
3090 vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3091 vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3092 full ? ffs->fs_descs_count + 1 : 0);
3093 vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3094 high ? ffs->hs_descs_count + 1 : 0);
3095 vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3096 super ? ffs->ss_descs_count + 1 : 0);
3097 vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3098 vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3099 c->cdev->use_os_string ? ffs->interfaces_count : 0);
3100 vla_item_with_sz(d, char[16], ext_compat,
3101 c->cdev->use_os_string ? ffs->interfaces_count : 0);
3102 vla_item_with_sz(d, struct usb_os_desc, os_desc,
3103 c->cdev->use_os_string ? ffs->interfaces_count : 0);
3104 vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3105 ffs->ms_os_descs_ext_prop_count);
3106 vla_item_with_sz(d, char, ext_prop_name,
3107 ffs->ms_os_descs_ext_prop_name_len);
3108 vla_item_with_sz(d, char, ext_prop_data,
3109 ffs->ms_os_descs_ext_prop_data_len);
3110 vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3111 char *vlabuf;
3112
3113 ENTER();
3114
3115 /* Has descriptors only for speeds gadget does not support */
3116 if (!(full | high | super))
3117 return -ENOTSUPP;
3118
3119 /* Allocate a single chunk, less management later on */
3120 vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3121 if (!vlabuf)
3122 return -ENOMEM;
3123
3124 ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3125 ffs->ms_os_descs_ext_prop_name_avail =
3126 vla_ptr(vlabuf, d, ext_prop_name);
3127 ffs->ms_os_descs_ext_prop_data_avail =
3128 vla_ptr(vlabuf, d, ext_prop_data);
3129
3130 /* Copy descriptors */
3131 memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3132 ffs->raw_descs_length);
3133
3134 memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3135 eps_ptr = vla_ptr(vlabuf, d, eps);
3136 for (i = 0; i < ffs->eps_count; i++)
3137 eps_ptr[i].num = -1;
3138
3139 /* Save pointers
3140 * d_eps == vlabuf, func->eps used to kfree vlabuf later
3141 */
3142 func->eps = vla_ptr(vlabuf, d, eps);
3143 func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3144
3145 /*
3146 * Go through all the endpoint descriptors and allocate
3147 * endpoints first, so that later we can rewrite the endpoint
3148 * numbers without worrying that it may be described later on.
3149 */
3150 if (full) {
3151 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3152 fs_len = ffs_do_descs(ffs->fs_descs_count,
3153 vla_ptr(vlabuf, d, raw_descs),
3154 d_raw_descs__sz,
3155 __ffs_func_bind_do_descs, func);
3156 if (fs_len < 0) {
3157 ret = fs_len;
3158 goto error;
3159 }
3160 } else {
3161 fs_len = 0;
3162 }
3163
3164 if (high) {
3165 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3166 hs_len = ffs_do_descs(ffs->hs_descs_count,
3167 vla_ptr(vlabuf, d, raw_descs) + fs_len,
3168 d_raw_descs__sz - fs_len,
3169 __ffs_func_bind_do_descs, func);
3170 if (hs_len < 0) {
3171 ret = hs_len;
3172 goto error;
3173 }
3174 } else {
3175 hs_len = 0;
3176 }
3177
3178 if (super) {
3179 func->function.ss_descriptors = func->function.ssp_descriptors =
3180 vla_ptr(vlabuf, d, ss_descs);
3181 ss_len = ffs_do_descs(ffs->ss_descs_count,
3182 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3183 d_raw_descs__sz - fs_len - hs_len,
3184 __ffs_func_bind_do_descs, func);
3185 if (ss_len < 0) {
3186 ret = ss_len;
3187 goto error;
3188 }
3189 } else {
3190 ss_len = 0;
3191 }
3192
3193 /*
3194 * Now handle interface numbers allocation and interface and
3195 * endpoint numbers rewriting. We can do that in one go
3196 * now.
3197 */
3198 ret = ffs_do_descs(ffs->fs_descs_count +
3199 (high ? ffs->hs_descs_count : 0) +
3200 (super ? ffs->ss_descs_count : 0),
3201 vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3202 __ffs_func_bind_do_nums, func);
3203 if (ret < 0)
3204 goto error;
3205
3206 func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3207 if (c->cdev->use_os_string) {
3208 for (i = 0; i < ffs->interfaces_count; ++i) {
3209 struct usb_os_desc *desc;
3210
3211 desc = func->function.os_desc_table[i].os_desc =
3212 vla_ptr(vlabuf, d, os_desc) +
3213 i * sizeof(struct usb_os_desc);
3214 desc->ext_compat_id =
3215 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3216 INIT_LIST_HEAD(&desc->ext_prop);
3217 }
3218 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3219 vla_ptr(vlabuf, d, raw_descs) +
3220 fs_len + hs_len + ss_len,
3221 d_raw_descs__sz - fs_len - hs_len -
3222 ss_len,
3223 __ffs_func_bind_do_os_desc, func);
3224 if (ret < 0)
3225 goto error;
3226 }
3227 func->function.os_desc_n =
3228 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3229
3230 /* And we're done */
3231 ffs_event_add(ffs, FUNCTIONFS_BIND);
3232 return 0;
3233
3234 error:
3235 /* XXX Do we need to release all claimed endpoints here? */
3236 return ret;
3237 }
3238
3239 static int ffs_func_bind(struct usb_configuration *c,
3240 struct usb_function *f)
3241 {
3242 struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3243 struct ffs_function *func = ffs_func_from_usb(f);
3244 int ret;
3245
3246 if (IS_ERR(ffs_opts))
3247 return PTR_ERR(ffs_opts);
3248
3249 ret = _ffs_func_bind(c, f);
3250 if (ret && !--ffs_opts->refcnt)
3251 functionfs_unbind(func->ffs);
3252
3253 return ret;
3254 }
3255
3256
3257 /* Other USB function hooks *************************************************/
3258
3259 static void ffs_reset_work(struct work_struct *work)
3260 {
3261 struct ffs_data *ffs = container_of(work,
3262 struct ffs_data, reset_work);
3263 ffs_data_reset(ffs);
3264 }
3265
3266 static int ffs_func_set_alt(struct usb_function *f,
3267 unsigned interface, unsigned alt)
3268 {
3269 struct ffs_function *func = ffs_func_from_usb(f);
3270 struct ffs_data *ffs = func->ffs;
3271 int ret = 0, intf;
3272
3273 if (alt != (unsigned)-1) {
3274 intf = ffs_func_revmap_intf(func, interface);
3275 if (intf < 0)
3276 return intf;
3277 }
3278
3279 if (ffs->func)
3280 ffs_func_eps_disable(ffs->func);
3281
3282 if (ffs->state == FFS_DEACTIVATED) {
3283 ffs->state = FFS_CLOSING;
3284 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3285 schedule_work(&ffs->reset_work);
3286 return -ENODEV;
3287 }
3288
3289 if (ffs->state != FFS_ACTIVE)
3290 return -ENODEV;
3291
3292 if (alt == (unsigned)-1) {
3293 ffs->func = NULL;
3294 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3295 return 0;
3296 }
3297
3298 ffs->func = func;
3299 ret = ffs_func_eps_enable(func);
3300 if (ret >= 0)
3301 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3302 return ret;
3303 }
3304
3305 static void ffs_func_disable(struct usb_function *f)
3306 {
3307 ffs_func_set_alt(f, 0, (unsigned)-1);
3308 }
3309
3310 static int ffs_func_setup(struct usb_function *f,
3311 const struct usb_ctrlrequest *creq)
3312 {
3313 struct ffs_function *func = ffs_func_from_usb(f);
3314 struct ffs_data *ffs = func->ffs;
3315 unsigned long flags;
3316 int ret;
3317
3318 ENTER();
3319
3320 pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3321 pr_vdebug("creq->bRequest = %02x\n", creq->bRequest);
3322 pr_vdebug("creq->wValue = %04x\n", le16_to_cpu(creq->wValue));
3323 pr_vdebug("creq->wIndex = %04x\n", le16_to_cpu(creq->wIndex));
3324 pr_vdebug("creq->wLength = %04x\n", le16_to_cpu(creq->wLength));
3325
3326 /*
3327 * Most requests directed to interface go through here
3328 * (notable exceptions are set/get interface) so we need to
3329 * handle them. All other either handled by composite or
3330 * passed to usb_configuration->setup() (if one is set). No
3331 * matter, we will handle requests directed to endpoint here
3332 * as well (as it's straightforward). Other request recipient
3333 * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3334 * is being used.
3335 */
3336 if (ffs->state != FFS_ACTIVE)
3337 return -ENODEV;
3338
3339 switch (creq->bRequestType & USB_RECIP_MASK) {
3340 case USB_RECIP_INTERFACE:
3341 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3342 if (ret < 0)
3343 return ret;
3344 break;
3345
3346 case USB_RECIP_ENDPOINT:
3347 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3348 if (ret < 0)
3349 return ret;
3350 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3351 ret = func->ffs->eps_addrmap[ret];
3352 break;
3353
3354 default:
3355 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3356 ret = le16_to_cpu(creq->wIndex);
3357 else
3358 return -EOPNOTSUPP;
3359 }
3360
3361 spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3362 ffs->ev.setup = *creq;
3363 ffs->ev.setup.wIndex = cpu_to_le16(ret);
3364 __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3365 spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3366
3367 return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3368 }
3369
3370 static bool ffs_func_req_match(struct usb_function *f,
3371 const struct usb_ctrlrequest *creq,
3372 bool config0)
3373 {
3374 struct ffs_function *func = ffs_func_from_usb(f);
3375
3376 if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3377 return false;
3378
3379 switch (creq->bRequestType & USB_RECIP_MASK) {
3380 case USB_RECIP_INTERFACE:
3381 return (ffs_func_revmap_intf(func,
3382 le16_to_cpu(creq->wIndex)) >= 0);
3383 case USB_RECIP_ENDPOINT:
3384 return (ffs_func_revmap_ep(func,
3385 le16_to_cpu(creq->wIndex)) >= 0);
3386 default:
3387 return (bool) (func->ffs->user_flags &
3388 FUNCTIONFS_ALL_CTRL_RECIP);
3389 }
3390 }
3391
3392 static void ffs_func_suspend(struct usb_function *f)
3393 {
3394 ENTER();
3395 ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3396 }
3397
3398 static void ffs_func_resume(struct usb_function *f)
3399 {
3400 ENTER();
3401 ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3402 }
3403
3404
3405 /* Endpoint and interface numbers reverse mapping ***************************/
3406
3407 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3408 {
3409 num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3410 return num ? num : -EDOM;
3411 }
3412
3413 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3414 {
3415 short *nums = func->interfaces_nums;
3416 unsigned count = func->ffs->interfaces_count;
3417
3418 for (; count; --count, ++nums) {
3419 if (*nums >= 0 && *nums == intf)
3420 return nums - func->interfaces_nums;
3421 }
3422
3423 return -EDOM;
3424 }
3425
3426
3427 /* Devices management *******************************************************/
3428
3429 static LIST_HEAD(ffs_devices);
3430
3431 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3432 {
3433 struct ffs_dev *dev;
3434
3435 if (!name)
3436 return NULL;
3437
3438 list_for_each_entry(dev, &ffs_devices, entry) {
3439 if (strcmp(dev->name, name) == 0)
3440 return dev;
3441 }
3442
3443 return NULL;
3444 }
3445
3446 /*
3447 * ffs_lock must be taken by the caller of this function
3448 */
3449 static struct ffs_dev *_ffs_get_single_dev(void)
3450 {
3451 struct ffs_dev *dev;
3452
3453 if (list_is_singular(&ffs_devices)) {
3454 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3455 if (dev->single)
3456 return dev;
3457 }
3458
3459 return NULL;
3460 }
3461
3462 /*
3463 * ffs_lock must be taken by the caller of this function
3464 */
3465 static struct ffs_dev *_ffs_find_dev(const char *name)
3466 {
3467 struct ffs_dev *dev;
3468
3469 dev = _ffs_get_single_dev();
3470 if (dev)
3471 return dev;
3472
3473 return _ffs_do_find_dev(name);
3474 }
3475
3476 /* Configfs support *********************************************************/
3477
3478 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3479 {
3480 return container_of(to_config_group(item), struct f_fs_opts,
3481 func_inst.group);
3482 }
3483
3484 static void ffs_attr_release(struct config_item *item)
3485 {
3486 struct f_fs_opts *opts = to_ffs_opts(item);
3487
3488 usb_put_function_instance(&opts->func_inst);
3489 }
3490
3491 static struct configfs_item_operations ffs_item_ops = {
3492 .release = ffs_attr_release,
3493 };
3494
3495 static const struct config_item_type ffs_func_type = {
3496 .ct_item_ops = &ffs_item_ops,
3497 .ct_owner = THIS_MODULE,
3498 };
3499
3500
3501 /* Function registration interface ******************************************/
3502
3503 static void ffs_free_inst(struct usb_function_instance *f)
3504 {
3505 struct f_fs_opts *opts;
3506
3507 opts = to_f_fs_opts(f);
3508 ffs_dev_lock();
3509 _ffs_free_dev(opts->dev);
3510 ffs_dev_unlock();
3511 kfree(opts);
3512 }
3513
3514 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3515 {
3516 if (strlen(name) >= sizeof_field(struct ffs_dev, name))
3517 return -ENAMETOOLONG;
3518 return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3519 }
3520
3521 static struct usb_function_instance *ffs_alloc_inst(void)
3522 {
3523 struct f_fs_opts *opts;
3524 struct ffs_dev *dev;
3525
3526 opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3527 if (!opts)
3528 return ERR_PTR(-ENOMEM);
3529
3530 opts->func_inst.set_inst_name = ffs_set_inst_name;
3531 opts->func_inst.free_func_inst = ffs_free_inst;
3532 ffs_dev_lock();
3533 dev = _ffs_alloc_dev();
3534 ffs_dev_unlock();
3535 if (IS_ERR(dev)) {
3536 kfree(opts);
3537 return ERR_CAST(dev);
3538 }
3539 opts->dev = dev;
3540 dev->opts = opts;
3541
3542 config_group_init_type_name(&opts->func_inst.group, "",
3543 &ffs_func_type);
3544 return &opts->func_inst;
3545 }
3546
3547 static void ffs_free(struct usb_function *f)
3548 {
3549 kfree(ffs_func_from_usb(f));
3550 }
3551
3552 static void ffs_func_unbind(struct usb_configuration *c,
3553 struct usb_function *f)
3554 {
3555 struct ffs_function *func = ffs_func_from_usb(f);
3556 struct ffs_data *ffs = func->ffs;
3557 struct f_fs_opts *opts =
3558 container_of(f->fi, struct f_fs_opts, func_inst);
3559 struct ffs_ep *ep = func->eps;
3560 unsigned count = ffs->eps_count;
3561 unsigned long flags;
3562
3563 ENTER();
3564 if (ffs->func == func) {
3565 ffs_func_eps_disable(func);
3566 ffs->func = NULL;
3567 }
3568
3569 if (!--opts->refcnt)
3570 functionfs_unbind(ffs);
3571
3572 /* cleanup after autoconfig */
3573 spin_lock_irqsave(&func->ffs->eps_lock, flags);
3574 while (count--) {
3575 if (ep->ep && ep->req)
3576 usb_ep_free_request(ep->ep, ep->req);
3577 ep->req = NULL;
3578 ++ep;
3579 }
3580 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3581 kfree(func->eps);
3582 func->eps = NULL;
3583 /*
3584 * eps, descriptors and interfaces_nums are allocated in the
3585 * same chunk so only one free is required.
3586 */
3587 func->function.fs_descriptors = NULL;
3588 func->function.hs_descriptors = NULL;
3589 func->function.ss_descriptors = NULL;
3590 func->function.ssp_descriptors = NULL;
3591 func->interfaces_nums = NULL;
3592
3593 ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3594 }
3595
3596 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3597 {
3598 struct ffs_function *func;
3599
3600 ENTER();
3601
3602 func = kzalloc(sizeof(*func), GFP_KERNEL);
3603 if (!func)
3604 return ERR_PTR(-ENOMEM);
3605
3606 func->function.name = "Function FS Gadget";
3607
3608 func->function.bind = ffs_func_bind;
3609 func->function.unbind = ffs_func_unbind;
3610 func->function.set_alt = ffs_func_set_alt;
3611 func->function.disable = ffs_func_disable;
3612 func->function.setup = ffs_func_setup;
3613 func->function.req_match = ffs_func_req_match;
3614 func->function.suspend = ffs_func_suspend;
3615 func->function.resume = ffs_func_resume;
3616 func->function.free_func = ffs_free;
3617
3618 return &func->function;
3619 }
3620
3621 /*
3622 * ffs_lock must be taken by the caller of this function
3623 */
3624 static struct ffs_dev *_ffs_alloc_dev(void)
3625 {
3626 struct ffs_dev *dev;
3627 int ret;
3628
3629 if (_ffs_get_single_dev())
3630 return ERR_PTR(-EBUSY);
3631
3632 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3633 if (!dev)
3634 return ERR_PTR(-ENOMEM);
3635
3636 if (list_empty(&ffs_devices)) {
3637 ret = functionfs_init();
3638 if (ret) {
3639 kfree(dev);
3640 return ERR_PTR(ret);
3641 }
3642 }
3643
3644 list_add(&dev->entry, &ffs_devices);
3645
3646 return dev;
3647 }
3648
3649 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3650 {
3651 struct ffs_dev *existing;
3652 int ret = 0;
3653
3654 ffs_dev_lock();
3655
3656 existing = _ffs_do_find_dev(name);
3657 if (!existing)
3658 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3659 else if (existing != dev)
3660 ret = -EBUSY;
3661
3662 ffs_dev_unlock();
3663
3664 return ret;
3665 }
3666 EXPORT_SYMBOL_GPL(ffs_name_dev);
3667
3668 int ffs_single_dev(struct ffs_dev *dev)
3669 {
3670 int ret;
3671
3672 ret = 0;
3673 ffs_dev_lock();
3674
3675 if (!list_is_singular(&ffs_devices))
3676 ret = -EBUSY;
3677 else
3678 dev->single = true;
3679
3680 ffs_dev_unlock();
3681 return ret;
3682 }
3683 EXPORT_SYMBOL_GPL(ffs_single_dev);
3684
3685 /*
3686 * ffs_lock must be taken by the caller of this function
3687 */
3688 static void _ffs_free_dev(struct ffs_dev *dev)
3689 {
3690 list_del(&dev->entry);
3691
3692 /* Clear the private_data pointer to stop incorrect dev access */
3693 if (dev->ffs_data)
3694 dev->ffs_data->private_data = NULL;
3695
3696 kfree(dev);
3697 if (list_empty(&ffs_devices))
3698 functionfs_cleanup();
3699 }
3700
3701 static void *ffs_acquire_dev(const char *dev_name)
3702 {
3703 struct ffs_dev *ffs_dev;
3704
3705 ENTER();
3706 ffs_dev_lock();
3707
3708 ffs_dev = _ffs_find_dev(dev_name);
3709 if (!ffs_dev)
3710 ffs_dev = ERR_PTR(-ENOENT);
3711 else if (ffs_dev->mounted)
3712 ffs_dev = ERR_PTR(-EBUSY);
3713 else if (ffs_dev->ffs_acquire_dev_callback &&
3714 ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3715 ffs_dev = ERR_PTR(-ENOENT);
3716 else
3717 ffs_dev->mounted = true;
3718
3719 ffs_dev_unlock();
3720 return ffs_dev;
3721 }
3722
3723 static void ffs_release_dev(struct ffs_data *ffs_data)
3724 {
3725 struct ffs_dev *ffs_dev;
3726
3727 ENTER();
3728 ffs_dev_lock();
3729
3730 ffs_dev = ffs_data->private_data;
3731 if (ffs_dev) {
3732 ffs_dev->mounted = false;
3733
3734 if (ffs_dev->ffs_release_dev_callback)
3735 ffs_dev->ffs_release_dev_callback(ffs_dev);
3736 }
3737
3738 ffs_dev_unlock();
3739 }
3740
3741 static int ffs_ready(struct ffs_data *ffs)
3742 {
3743 struct ffs_dev *ffs_obj;
3744 int ret = 0;
3745
3746 ENTER();
3747 ffs_dev_lock();
3748
3749 ffs_obj = ffs->private_data;
3750 if (!ffs_obj) {
3751 ret = -EINVAL;
3752 goto done;
3753 }
3754 if (WARN_ON(ffs_obj->desc_ready)) {
3755 ret = -EBUSY;
3756 goto done;
3757 }
3758
3759 ffs_obj->desc_ready = true;
3760 ffs_obj->ffs_data = ffs;
3761
3762 if (ffs_obj->ffs_ready_callback) {
3763 ret = ffs_obj->ffs_ready_callback(ffs);
3764 if (ret)
3765 goto done;
3766 }
3767
3768 set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3769 done:
3770 ffs_dev_unlock();
3771 return ret;
3772 }
3773
3774 static void ffs_closed(struct ffs_data *ffs)
3775 {
3776 struct ffs_dev *ffs_obj;
3777 struct f_fs_opts *opts;
3778 struct config_item *ci;
3779
3780 ENTER();
3781 ffs_dev_lock();
3782
3783 ffs_obj = ffs->private_data;
3784 if (!ffs_obj)
3785 goto done;
3786
3787 ffs_obj->desc_ready = false;
3788 ffs_obj->ffs_data = NULL;
3789
3790 if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3791 ffs_obj->ffs_closed_callback)
3792 ffs_obj->ffs_closed_callback(ffs);
3793
3794 if (ffs_obj->opts)
3795 opts = ffs_obj->opts;
3796 else
3797 goto done;
3798
3799 if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3800 || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3801 goto done;
3802
3803 ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3804 ffs_dev_unlock();
3805
3806 if (test_bit(FFS_FL_BOUND, &ffs->flags))
3807 unregister_gadget_item(ci);
3808 return;
3809 done:
3810 ffs_dev_unlock();
3811 }
3812
3813 /* Misc helper functions ****************************************************/
3814
3815 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3816 {
3817 return nonblock
3818 ? mutex_trylock(mutex) ? 0 : -EAGAIN
3819 : mutex_lock_interruptible(mutex);
3820 }
3821
3822 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3823 {
3824 char *data;
3825
3826 if (!len)
3827 return NULL;
3828
3829 data = kmalloc(len, GFP_KERNEL);
3830 if (!data)
3831 return ERR_PTR(-ENOMEM);
3832
3833 if (copy_from_user(data, buf, len)) {
3834 kfree(data);
3835 return ERR_PTR(-EFAULT);
3836 }
3837
3838 pr_vdebug("Buffer from user space:\n");
3839 ffs_dump_mem("", data, len);
3840
3841 return data;
3842 }
3843
3844 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3845 MODULE_LICENSE("GPL");
3846 MODULE_AUTHOR("Michal Nazarewicz");
Linux with added FPC-III support