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
ffs_func_from_usb(struct usb_function * f)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
ffs_setup_state_clear_cancelled(struct ffs_data * ffs)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
127 struct ffs_epfile {
128 /* Protects ep->ep and ep->req. */
129 struct mutex mutex;
130
131 struct ffs_data *ffs;
132 struct ffs_ep *ep; /* P: ffs->eps_lock */
133
134 struct dentry *dentry;
135
136 /*
137 * Buffer for holding data from partial reads which may happen since
138 * we’re rounding user read requests to a multiple of a max packet size.
139 *
140 * The pointer is initialised with NULL value and may be set by
141 * __ffs_epfile_read_data function to point to a temporary buffer.
142 *
143 * In normal operation, calls to __ffs_epfile_read_buffered will consume
144 * data from said buffer and eventually free it. Importantly, while the
145 * function is using the buffer, it sets the pointer to NULL. This is
146 * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
147 * can never run concurrently (they are synchronised by epfile->mutex)
148 * so the latter will not assign a new value to the pointer.
149 *
150 * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
151 * valid) and sets the pointer to READ_BUFFER_DROP value. This special
152 * value is crux of the synchronisation between ffs_func_eps_disable and
153 * __ffs_epfile_read_data.
154 *
155 * Once __ffs_epfile_read_data is about to finish it will try to set the
156 * pointer back to its old value (as described above), but seeing as the
157 * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
158 * the buffer.
159 *
160 * == State transitions ==
161 *
162 * • ptr == NULL: (initial state)
163 * ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
164 * ◦ __ffs_epfile_read_buffered: nop
165 * ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
166 * ◦ reading finishes: n/a, not in ‘and reading’ state
167 * • ptr == DROP:
168 * ◦ __ffs_epfile_read_buffer_free: nop
169 * ◦ __ffs_epfile_read_buffered: go to ptr == NULL
170 * ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
171 * ◦ reading finishes: n/a, not in ‘and reading’ state
172 * • ptr == buf:
173 * ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
174 * ◦ __ffs_epfile_read_buffered: go to ptr == NULL and reading
175 * ◦ __ffs_epfile_read_data: n/a, __ffs_epfile_read_buffered
176 * is always called first
177 * ◦ reading finishes: n/a, not in ‘and reading’ state
178 * • ptr == NULL and reading:
179 * ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
180 * ◦ __ffs_epfile_read_buffered: n/a, mutex is held
181 * ◦ __ffs_epfile_read_data: n/a, mutex is held
182 * ◦ reading finishes and …
183 * … all data read: free buf, go to ptr == NULL
184 * … otherwise: go to ptr == buf and reading
185 * • ptr == DROP and reading:
186 * ◦ __ffs_epfile_read_buffer_free: nop
187 * ◦ __ffs_epfile_read_buffered: n/a, mutex is held
188 * ◦ __ffs_epfile_read_data: n/a, mutex is held
189 * ◦ reading finishes: free buf, go to ptr == DROP
190 */
191 struct ffs_buffer *read_buffer;
192 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
193
194 char name[5];
195
196 unsigned char in; /* P: ffs->eps_lock */
197 unsigned char isoc; /* P: ffs->eps_lock */
198
199 unsigned char _pad;
200 };
201
202 struct ffs_buffer {
203 size_t length;
204 char *data;
205 char storage[];
206 };
207
208 /* ffs_io_data structure ***************************************************/
209
210 struct ffs_io_data {
211 bool aio;
212 bool read;
213
214 struct kiocb *kiocb;
215 struct iov_iter data;
216 const void *to_free;
217 char *buf;
218
219 struct mm_struct *mm;
220 struct work_struct work;
221
222 struct usb_ep *ep;
223 struct usb_request *req;
224 struct sg_table sgt;
225 bool use_sg;
226
227 struct ffs_data *ffs;
228
229 int status;
230 struct completion done;
231 };
232
233 struct ffs_desc_helper {
234 struct ffs_data *ffs;
235 unsigned interfaces_count;
236 unsigned eps_count;
237 };
238
239 static int __must_check ffs_epfiles_create(struct ffs_data *ffs);
240 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
241
242 static struct dentry *
243 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
244 const struct file_operations *fops);
245
246 /* Devices management *******************************************************/
247
248 DEFINE_MUTEX(ffs_lock);
249 EXPORT_SYMBOL_GPL(ffs_lock);
250
251 static struct ffs_dev *_ffs_find_dev(const char *name);
252 static struct ffs_dev *_ffs_alloc_dev(void);
253 static void _ffs_free_dev(struct ffs_dev *dev);
254 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data);
255 static void ffs_release_dev(struct ffs_dev *ffs_dev);
256 static int ffs_ready(struct ffs_data *ffs);
257 static void ffs_closed(struct ffs_data *ffs);
258
259 /* Misc helper functions ****************************************************/
260
261 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
262 __attribute__((warn_unused_result, nonnull));
263 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
264 __attribute__((warn_unused_result, nonnull));
265
266
267 /* Control file aka ep0 *****************************************************/
268
ffs_ep0_complete(struct usb_ep * ep,struct usb_request * req)269 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
270 {
271 struct ffs_data *ffs = req->context;
272
273 complete(&ffs->ep0req_completion);
274 }
275
__ffs_ep0_queue_wait(struct ffs_data * ffs,char * data,size_t len)276 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
277 __releases(&ffs->ev.waitq.lock)
278 {
279 struct usb_request *req = ffs->ep0req;
280 int ret;
281
282 req->zero = len < le16_to_cpu(ffs->ev.setup.wLength);
283
284 spin_unlock_irq(&ffs->ev.waitq.lock);
285
286 req->buf = data;
287 req->length = len;
288
289 /*
290 * UDC layer requires to provide a buffer even for ZLP, but should
291 * not use it at all. Let's provide some poisoned pointer to catch
292 * possible bug in the driver.
293 */
294 if (req->buf == NULL)
295 req->buf = (void *)0xDEADBABE;
296
297 reinit_completion(&ffs->ep0req_completion);
298
299 ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
300 if (ret < 0)
301 return ret;
302
303 ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
304 if (ret) {
305 usb_ep_dequeue(ffs->gadget->ep0, req);
306 return -EINTR;
307 }
308
309 ffs->setup_state = FFS_NO_SETUP;
310 return req->status ? req->status : req->actual;
311 }
312
__ffs_ep0_stall(struct ffs_data * ffs)313 static int __ffs_ep0_stall(struct ffs_data *ffs)
314 {
315 if (ffs->ev.can_stall) {
316 pr_vdebug("ep0 stall\n");
317 usb_ep_set_halt(ffs->gadget->ep0);
318 ffs->setup_state = FFS_NO_SETUP;
319 return -EL2HLT;
320 } else {
321 pr_debug("bogus ep0 stall!\n");
322 return -ESRCH;
323 }
324 }
325
ffs_ep0_write(struct file * file,const char __user * buf,size_t len,loff_t * ptr)326 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
327 size_t len, loff_t *ptr)
328 {
329 struct ffs_data *ffs = file->private_data;
330 ssize_t ret;
331 char *data;
332
333 ENTER();
334
335 /* Fast check if setup was canceled */
336 if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
337 return -EIDRM;
338
339 /* Acquire mutex */
340 ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
341 if (ret < 0)
342 return ret;
343
344 /* Check state */
345 switch (ffs->state) {
346 case FFS_READ_DESCRIPTORS:
347 case FFS_READ_STRINGS:
348 /* Copy data */
349 if (len < 16) {
350 ret = -EINVAL;
351 break;
352 }
353
354 data = ffs_prepare_buffer(buf, len);
355 if (IS_ERR(data)) {
356 ret = PTR_ERR(data);
357 break;
358 }
359
360 /* Handle data */
361 if (ffs->state == FFS_READ_DESCRIPTORS) {
362 pr_info("read descriptors\n");
363 ret = __ffs_data_got_descs(ffs, data, len);
364 if (ret < 0)
365 break;
366
367 ffs->state = FFS_READ_STRINGS;
368 ret = len;
369 } else {
370 pr_info("read strings\n");
371 ret = __ffs_data_got_strings(ffs, data, len);
372 if (ret < 0)
373 break;
374
375 ret = ffs_epfiles_create(ffs);
376 if (ret) {
377 ffs->state = FFS_CLOSING;
378 break;
379 }
380
381 ffs->state = FFS_ACTIVE;
382 mutex_unlock(&ffs->mutex);
383
384 ret = ffs_ready(ffs);
385 if (ret < 0) {
386 ffs->state = FFS_CLOSING;
387 return ret;
388 }
389
390 return len;
391 }
392 break;
393
394 case FFS_ACTIVE:
395 data = NULL;
396 /*
397 * We're called from user space, we can use _irq
398 * rather then _irqsave
399 */
400 spin_lock_irq(&ffs->ev.waitq.lock);
401 switch (ffs_setup_state_clear_cancelled(ffs)) {
402 case FFS_SETUP_CANCELLED:
403 ret = -EIDRM;
404 goto done_spin;
405
406 case FFS_NO_SETUP:
407 ret = -ESRCH;
408 goto done_spin;
409
410 case FFS_SETUP_PENDING:
411 break;
412 }
413
414 /* FFS_SETUP_PENDING */
415 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
416 spin_unlock_irq(&ffs->ev.waitq.lock);
417 ret = __ffs_ep0_stall(ffs);
418 break;
419 }
420
421 /* FFS_SETUP_PENDING and not stall */
422 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
423
424 spin_unlock_irq(&ffs->ev.waitq.lock);
425
426 data = ffs_prepare_buffer(buf, len);
427 if (IS_ERR(data)) {
428 ret = PTR_ERR(data);
429 break;
430 }
431
432 spin_lock_irq(&ffs->ev.waitq.lock);
433
434 /*
435 * We are guaranteed to be still in FFS_ACTIVE state
436 * but the state of setup could have changed from
437 * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
438 * to check for that. If that happened we copied data
439 * from user space in vain but it's unlikely.
440 *
441 * For sure we are not in FFS_NO_SETUP since this is
442 * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
443 * transition can be performed and it's protected by
444 * mutex.
445 */
446 if (ffs_setup_state_clear_cancelled(ffs) ==
447 FFS_SETUP_CANCELLED) {
448 ret = -EIDRM;
449 done_spin:
450 spin_unlock_irq(&ffs->ev.waitq.lock);
451 } else {
452 /* unlocks spinlock */
453 ret = __ffs_ep0_queue_wait(ffs, data, len);
454 }
455 kfree(data);
456 break;
457
458 default:
459 ret = -EBADFD;
460 break;
461 }
462
463 mutex_unlock(&ffs->mutex);
464 return ret;
465 }
466
467 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
__ffs_ep0_read_events(struct ffs_data * ffs,char __user * buf,size_t n)468 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
469 size_t n)
470 __releases(&ffs->ev.waitq.lock)
471 {
472 /*
473 * n cannot be bigger than ffs->ev.count, which cannot be bigger than
474 * size of ffs->ev.types array (which is four) so that's how much space
475 * we reserve.
476 */
477 struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
478 const size_t size = n * sizeof *events;
479 unsigned i = 0;
480
481 memset(events, 0, size);
482
483 do {
484 events[i].type = ffs->ev.types[i];
485 if (events[i].type == FUNCTIONFS_SETUP) {
486 events[i].u.setup = ffs->ev.setup;
487 ffs->setup_state = FFS_SETUP_PENDING;
488 }
489 } while (++i < n);
490
491 ffs->ev.count -= n;
492 if (ffs->ev.count)
493 memmove(ffs->ev.types, ffs->ev.types + n,
494 ffs->ev.count * sizeof *ffs->ev.types);
495
496 spin_unlock_irq(&ffs->ev.waitq.lock);
497 mutex_unlock(&ffs->mutex);
498
499 return copy_to_user(buf, events, size) ? -EFAULT : size;
500 }
501
ffs_ep0_read(struct file * file,char __user * buf,size_t len,loff_t * ptr)502 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
503 size_t len, loff_t *ptr)
504 {
505 struct ffs_data *ffs = file->private_data;
506 char *data = NULL;
507 size_t n;
508 int ret;
509
510 ENTER();
511
512 /* Fast check if setup was canceled */
513 if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
514 return -EIDRM;
515
516 /* Acquire mutex */
517 ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
518 if (ret < 0)
519 return ret;
520
521 /* Check state */
522 if (ffs->state != FFS_ACTIVE) {
523 ret = -EBADFD;
524 goto done_mutex;
525 }
526
527 /*
528 * We're called from user space, we can use _irq rather then
529 * _irqsave
530 */
531 spin_lock_irq(&ffs->ev.waitq.lock);
532
533 switch (ffs_setup_state_clear_cancelled(ffs)) {
534 case FFS_SETUP_CANCELLED:
535 ret = -EIDRM;
536 break;
537
538 case FFS_NO_SETUP:
539 n = len / sizeof(struct usb_functionfs_event);
540 if (!n) {
541 ret = -EINVAL;
542 break;
543 }
544
545 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
546 ret = -EAGAIN;
547 break;
548 }
549
550 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
551 ffs->ev.count)) {
552 ret = -EINTR;
553 break;
554 }
555
556 /* unlocks spinlock */
557 return __ffs_ep0_read_events(ffs, buf,
558 min(n, (size_t)ffs->ev.count));
559
560 case FFS_SETUP_PENDING:
561 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
562 spin_unlock_irq(&ffs->ev.waitq.lock);
563 ret = __ffs_ep0_stall(ffs);
564 goto done_mutex;
565 }
566
567 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
568
569 spin_unlock_irq(&ffs->ev.waitq.lock);
570
571 if (len) {
572 data = kmalloc(len, GFP_KERNEL);
573 if (!data) {
574 ret = -ENOMEM;
575 goto done_mutex;
576 }
577 }
578
579 spin_lock_irq(&ffs->ev.waitq.lock);
580
581 /* See ffs_ep0_write() */
582 if (ffs_setup_state_clear_cancelled(ffs) ==
583 FFS_SETUP_CANCELLED) {
584 ret = -EIDRM;
585 break;
586 }
587
588 /* unlocks spinlock */
589 ret = __ffs_ep0_queue_wait(ffs, data, len);
590 if ((ret > 0) && (copy_to_user(buf, data, len)))
591 ret = -EFAULT;
592 goto done_mutex;
593
594 default:
595 ret = -EBADFD;
596 break;
597 }
598
599 spin_unlock_irq(&ffs->ev.waitq.lock);
600 done_mutex:
601 mutex_unlock(&ffs->mutex);
602 kfree(data);
603 return ret;
604 }
605
ffs_ep0_open(struct inode * inode,struct file * file)606 static int ffs_ep0_open(struct inode *inode, struct file *file)
607 {
608 struct ffs_data *ffs = inode->i_private;
609
610 ENTER();
611
612 if (ffs->state == FFS_CLOSING)
613 return -EBUSY;
614
615 file->private_data = ffs;
616 ffs_data_opened(ffs);
617
618 return stream_open(inode, file);
619 }
620
ffs_ep0_release(struct inode * inode,struct file * file)621 static int ffs_ep0_release(struct inode *inode, struct file *file)
622 {
623 struct ffs_data *ffs = file->private_data;
624
625 ENTER();
626
627 ffs_data_closed(ffs);
628
629 return 0;
630 }
631
ffs_ep0_ioctl(struct file * file,unsigned code,unsigned long value)632 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
633 {
634 struct ffs_data *ffs = file->private_data;
635 struct usb_gadget *gadget = ffs->gadget;
636 long ret;
637
638 ENTER();
639
640 if (code == FUNCTIONFS_INTERFACE_REVMAP) {
641 struct ffs_function *func = ffs->func;
642 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
643 } else if (gadget && gadget->ops->ioctl) {
644 ret = gadget->ops->ioctl(gadget, code, value);
645 } else {
646 ret = -ENOTTY;
647 }
648
649 return ret;
650 }
651
ffs_ep0_poll(struct file * file,poll_table * wait)652 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
653 {
654 struct ffs_data *ffs = file->private_data;
655 __poll_t mask = EPOLLWRNORM;
656 int ret;
657
658 poll_wait(file, &ffs->ev.waitq, wait);
659
660 ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
661 if (ret < 0)
662 return mask;
663
664 switch (ffs->state) {
665 case FFS_READ_DESCRIPTORS:
666 case FFS_READ_STRINGS:
667 mask |= EPOLLOUT;
668 break;
669
670 case FFS_ACTIVE:
671 switch (ffs->setup_state) {
672 case FFS_NO_SETUP:
673 if (ffs->ev.count)
674 mask |= EPOLLIN;
675 break;
676
677 case FFS_SETUP_PENDING:
678 case FFS_SETUP_CANCELLED:
679 mask |= (EPOLLIN | EPOLLOUT);
680 break;
681 }
682 break;
683
684 case FFS_CLOSING:
685 break;
686 case FFS_DEACTIVATED:
687 break;
688 }
689
690 mutex_unlock(&ffs->mutex);
691
692 return mask;
693 }
694
695 static const struct file_operations ffs_ep0_operations = {
696 .llseek = no_llseek,
697
698 .open = ffs_ep0_open,
699 .write = ffs_ep0_write,
700 .read = ffs_ep0_read,
701 .release = ffs_ep0_release,
702 .unlocked_ioctl = ffs_ep0_ioctl,
703 .poll = ffs_ep0_poll,
704 };
705
706
707 /* "Normal" endpoints operations ********************************************/
708
ffs_epfile_io_complete(struct usb_ep * _ep,struct usb_request * req)709 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
710 {
711 struct ffs_io_data *io_data = req->context;
712
713 ENTER();
714 if (req->status)
715 io_data->status = req->status;
716 else
717 io_data->status = req->actual;
718
719 complete(&io_data->done);
720 }
721
ffs_copy_to_iter(void * data,int data_len,struct iov_iter * iter)722 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
723 {
724 ssize_t ret = copy_to_iter(data, data_len, iter);
725 if (ret == data_len)
726 return ret;
727
728 if (iov_iter_count(iter))
729 return -EFAULT;
730
731 /*
732 * Dear user space developer!
733 *
734 * TL;DR: To stop getting below error message in your kernel log, change
735 * user space code using functionfs to align read buffers to a max
736 * packet size.
737 *
738 * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
739 * packet size. When unaligned buffer is passed to functionfs, it
740 * internally uses a larger, aligned buffer so that such UDCs are happy.
741 *
742 * Unfortunately, this means that host may send more data than was
743 * requested in read(2) system call. f_fs doesn’t know what to do with
744 * that excess data so it simply drops it.
745 *
746 * Was the buffer aligned in the first place, no such problem would
747 * happen.
748 *
749 * Data may be dropped only in AIO reads. Synchronous reads are handled
750 * by splitting a request into multiple parts. This splitting may still
751 * be a problem though so it’s likely best to align the buffer
752 * regardless of it being AIO or not..
753 *
754 * This only affects OUT endpoints, i.e. reading data with a read(2),
755 * aio_read(2) etc. system calls. Writing data to an IN endpoint is not
756 * affected.
757 */
758 pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
759 "Align read buffer size to max packet size to avoid the problem.\n",
760 data_len, ret);
761
762 return ret;
763 }
764
765 /*
766 * allocate a virtually contiguous buffer and create a scatterlist describing it
767 * @sg_table - pointer to a place to be filled with sg_table contents
768 * @size - required buffer size
769 */
ffs_build_sg_list(struct sg_table * sgt,size_t sz)770 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
771 {
772 struct page **pages;
773 void *vaddr, *ptr;
774 unsigned int n_pages;
775 int i;
776
777 vaddr = vmalloc(sz);
778 if (!vaddr)
779 return NULL;
780
781 n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
782 pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
783 if (!pages) {
784 vfree(vaddr);
785
786 return NULL;
787 }
788 for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
789 pages[i] = vmalloc_to_page(ptr);
790
791 if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
792 kvfree(pages);
793 vfree(vaddr);
794
795 return NULL;
796 }
797 kvfree(pages);
798
799 return vaddr;
800 }
801
ffs_alloc_buffer(struct ffs_io_data * io_data,size_t data_len)802 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
803 size_t data_len)
804 {
805 if (io_data->use_sg)
806 return ffs_build_sg_list(&io_data->sgt, data_len);
807
808 return kmalloc(data_len, GFP_KERNEL);
809 }
810
ffs_free_buffer(struct ffs_io_data * io_data)811 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
812 {
813 if (!io_data->buf)
814 return;
815
816 if (io_data->use_sg) {
817 sg_free_table(&io_data->sgt);
818 vfree(io_data->buf);
819 } else {
820 kfree(io_data->buf);
821 }
822 }
823
ffs_user_copy_worker(struct work_struct * work)824 static void ffs_user_copy_worker(struct work_struct *work)
825 {
826 struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
827 work);
828 int ret = io_data->req->status ? io_data->req->status :
829 io_data->req->actual;
830 bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
831
832 if (io_data->read && ret > 0) {
833 kthread_use_mm(io_data->mm);
834 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
835 kthread_unuse_mm(io_data->mm);
836 }
837
838 io_data->kiocb->ki_complete(io_data->kiocb, ret);
839
840 if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
841 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
842
843 usb_ep_free_request(io_data->ep, io_data->req);
844
845 if (io_data->read)
846 kfree(io_data->to_free);
847 ffs_free_buffer(io_data);
848 kfree(io_data);
849 }
850
ffs_epfile_async_io_complete(struct usb_ep * _ep,struct usb_request * req)851 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
852 struct usb_request *req)
853 {
854 struct ffs_io_data *io_data = req->context;
855 struct ffs_data *ffs = io_data->ffs;
856
857 ENTER();
858
859 INIT_WORK(&io_data->work, ffs_user_copy_worker);
860 queue_work(ffs->io_completion_wq, &io_data->work);
861 }
862
__ffs_epfile_read_buffer_free(struct ffs_epfile * epfile)863 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
864 {
865 /*
866 * See comment in struct ffs_epfile for full read_buffer pointer
867 * synchronisation story.
868 */
869 struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
870 if (buf && buf != READ_BUFFER_DROP)
871 kfree(buf);
872 }
873
874 /* Assumes epfile->mutex is held. */
__ffs_epfile_read_buffered(struct ffs_epfile * epfile,struct iov_iter * iter)875 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
876 struct iov_iter *iter)
877 {
878 /*
879 * Null out epfile->read_buffer so ffs_func_eps_disable does not free
880 * the buffer while we are using it. See comment in struct ffs_epfile
881 * for full read_buffer pointer synchronisation story.
882 */
883 struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
884 ssize_t ret;
885 if (!buf || buf == READ_BUFFER_DROP)
886 return 0;
887
888 ret = copy_to_iter(buf->data, buf->length, iter);
889 if (buf->length == ret) {
890 kfree(buf);
891 return ret;
892 }
893
894 if (iov_iter_count(iter)) {
895 ret = -EFAULT;
896 } else {
897 buf->length -= ret;
898 buf->data += ret;
899 }
900
901 if (cmpxchg(&epfile->read_buffer, NULL, buf))
902 kfree(buf);
903
904 return ret;
905 }
906
907 /* Assumes epfile->mutex is held. */
__ffs_epfile_read_data(struct ffs_epfile * epfile,void * data,int data_len,struct iov_iter * iter)908 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
909 void *data, int data_len,
910 struct iov_iter *iter)
911 {
912 struct ffs_buffer *buf;
913
914 ssize_t ret = copy_to_iter(data, data_len, iter);
915 if (data_len == ret)
916 return ret;
917
918 if (iov_iter_count(iter))
919 return -EFAULT;
920
921 /* See ffs_copy_to_iter for more context. */
922 pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
923 data_len, ret);
924
925 data_len -= ret;
926 buf = kmalloc(struct_size(buf, storage, data_len), GFP_KERNEL);
927 if (!buf)
928 return -ENOMEM;
929 buf->length = data_len;
930 buf->data = buf->storage;
931 memcpy(buf->storage, data + ret, flex_array_size(buf, storage, data_len));
932
933 /*
934 * At this point read_buffer is NULL or READ_BUFFER_DROP (if
935 * ffs_func_eps_disable has been called in the meanwhile). See comment
936 * in struct ffs_epfile for full read_buffer pointer synchronisation
937 * story.
938 */
939 if (cmpxchg(&epfile->read_buffer, NULL, buf))
940 kfree(buf);
941
942 return ret;
943 }
944
ffs_epfile_io(struct file * file,struct ffs_io_data * io_data)945 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
946 {
947 struct ffs_epfile *epfile = file->private_data;
948 struct usb_request *req;
949 struct ffs_ep *ep;
950 char *data = NULL;
951 ssize_t ret, data_len = -EINVAL;
952 int halt;
953
954 /* Are we still active? */
955 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
956 return -ENODEV;
957
958 /* Wait for endpoint to be enabled */
959 ep = epfile->ep;
960 if (!ep) {
961 if (file->f_flags & O_NONBLOCK)
962 return -EAGAIN;
963
964 ret = wait_event_interruptible(
965 epfile->ffs->wait, (ep = epfile->ep));
966 if (ret)
967 return -EINTR;
968 }
969
970 /* Do we halt? */
971 halt = (!io_data->read == !epfile->in);
972 if (halt && epfile->isoc)
973 return -EINVAL;
974
975 /* We will be using request and read_buffer */
976 ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
977 if (ret)
978 goto error;
979
980 /* Allocate & copy */
981 if (!halt) {
982 struct usb_gadget *gadget;
983
984 /*
985 * Do we have buffered data from previous partial read? Check
986 * that for synchronous case only because we do not have
987 * facility to ‘wake up’ a pending asynchronous read and push
988 * buffered data to it which we would need to make things behave
989 * consistently.
990 */
991 if (!io_data->aio && io_data->read) {
992 ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
993 if (ret)
994 goto error_mutex;
995 }
996
997 /*
998 * if we _do_ wait above, the epfile->ffs->gadget might be NULL
999 * before the waiting completes, so do not assign to 'gadget'
1000 * earlier
1001 */
1002 gadget = epfile->ffs->gadget;
1003
1004 spin_lock_irq(&epfile->ffs->eps_lock);
1005 /* In the meantime, endpoint got disabled or changed. */
1006 if (epfile->ep != ep) {
1007 ret = -ESHUTDOWN;
1008 goto error_lock;
1009 }
1010 data_len = iov_iter_count(&io_data->data);
1011 /*
1012 * Controller may require buffer size to be aligned to
1013 * maxpacketsize of an out endpoint.
1014 */
1015 if (io_data->read)
1016 data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1017
1018 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1019 spin_unlock_irq(&epfile->ffs->eps_lock);
1020
1021 data = ffs_alloc_buffer(io_data, data_len);
1022 if (!data) {
1023 ret = -ENOMEM;
1024 goto error_mutex;
1025 }
1026 if (!io_data->read &&
1027 !copy_from_iter_full(data, data_len, &io_data->data)) {
1028 ret = -EFAULT;
1029 goto error_mutex;
1030 }
1031 }
1032
1033 spin_lock_irq(&epfile->ffs->eps_lock);
1034
1035 if (epfile->ep != ep) {
1036 /* In the meantime, endpoint got disabled or changed. */
1037 ret = -ESHUTDOWN;
1038 } else if (halt) {
1039 ret = usb_ep_set_halt(ep->ep);
1040 if (!ret)
1041 ret = -EBADMSG;
1042 } else if (data_len == -EINVAL) {
1043 /*
1044 * Sanity Check: even though data_len can't be used
1045 * uninitialized at the time I write this comment, some
1046 * compilers complain about this situation.
1047 * In order to keep the code clean from warnings, data_len is
1048 * being initialized to -EINVAL during its declaration, which
1049 * means we can't rely on compiler anymore to warn no future
1050 * changes won't result in data_len being used uninitialized.
1051 * For such reason, we're adding this redundant sanity check
1052 * here.
1053 */
1054 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1055 ret = -EINVAL;
1056 } else if (!io_data->aio) {
1057 bool interrupted = false;
1058
1059 req = ep->req;
1060 if (io_data->use_sg) {
1061 req->buf = NULL;
1062 req->sg = io_data->sgt.sgl;
1063 req->num_sgs = io_data->sgt.nents;
1064 } else {
1065 req->buf = data;
1066 req->num_sgs = 0;
1067 }
1068 req->length = data_len;
1069
1070 io_data->buf = data;
1071
1072 init_completion(&io_data->done);
1073 req->context = io_data;
1074 req->complete = ffs_epfile_io_complete;
1075
1076 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1077 if (ret < 0)
1078 goto error_lock;
1079
1080 spin_unlock_irq(&epfile->ffs->eps_lock);
1081
1082 if (wait_for_completion_interruptible(&io_data->done)) {
1083 spin_lock_irq(&epfile->ffs->eps_lock);
1084 if (epfile->ep != ep) {
1085 ret = -ESHUTDOWN;
1086 goto error_lock;
1087 }
1088 /*
1089 * To avoid race condition with ffs_epfile_io_complete,
1090 * dequeue the request first then check
1091 * status. usb_ep_dequeue API should guarantee no race
1092 * condition with req->complete callback.
1093 */
1094 usb_ep_dequeue(ep->ep, req);
1095 spin_unlock_irq(&epfile->ffs->eps_lock);
1096 wait_for_completion(&io_data->done);
1097 interrupted = io_data->status < 0;
1098 }
1099
1100 if (interrupted)
1101 ret = -EINTR;
1102 else if (io_data->read && io_data->status > 0)
1103 ret = __ffs_epfile_read_data(epfile, data, io_data->status,
1104 &io_data->data);
1105 else
1106 ret = io_data->status;
1107 goto error_mutex;
1108 } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1109 ret = -ENOMEM;
1110 } else {
1111 if (io_data->use_sg) {
1112 req->buf = NULL;
1113 req->sg = io_data->sgt.sgl;
1114 req->num_sgs = io_data->sgt.nents;
1115 } else {
1116 req->buf = data;
1117 req->num_sgs = 0;
1118 }
1119 req->length = data_len;
1120
1121 io_data->buf = data;
1122 io_data->ep = ep->ep;
1123 io_data->req = req;
1124 io_data->ffs = epfile->ffs;
1125
1126 req->context = io_data;
1127 req->complete = ffs_epfile_async_io_complete;
1128
1129 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1130 if (ret) {
1131 io_data->req = NULL;
1132 usb_ep_free_request(ep->ep, req);
1133 goto error_lock;
1134 }
1135
1136 ret = -EIOCBQUEUED;
1137 /*
1138 * Do not kfree the buffer in this function. It will be freed
1139 * by ffs_user_copy_worker.
1140 */
1141 data = NULL;
1142 }
1143
1144 error_lock:
1145 spin_unlock_irq(&epfile->ffs->eps_lock);
1146 error_mutex:
1147 mutex_unlock(&epfile->mutex);
1148 error:
1149 if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1150 ffs_free_buffer(io_data);
1151 return ret;
1152 }
1153
1154 static int
ffs_epfile_open(struct inode * inode,struct file * file)1155 ffs_epfile_open(struct inode *inode, struct file *file)
1156 {
1157 struct ffs_epfile *epfile = inode->i_private;
1158
1159 ENTER();
1160
1161 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1162 return -ENODEV;
1163
1164 file->private_data = epfile;
1165 ffs_data_opened(epfile->ffs);
1166
1167 return stream_open(inode, file);
1168 }
1169
ffs_aio_cancel(struct kiocb * kiocb)1170 static int ffs_aio_cancel(struct kiocb *kiocb)
1171 {
1172 struct ffs_io_data *io_data = kiocb->private;
1173 struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1174 unsigned long flags;
1175 int value;
1176
1177 ENTER();
1178
1179 spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1180
1181 if (io_data && io_data->ep && io_data->req)
1182 value = usb_ep_dequeue(io_data->ep, io_data->req);
1183 else
1184 value = -EINVAL;
1185
1186 spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1187
1188 return value;
1189 }
1190
ffs_epfile_write_iter(struct kiocb * kiocb,struct iov_iter * from)1191 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1192 {
1193 struct ffs_io_data io_data, *p = &io_data;
1194 ssize_t res;
1195
1196 ENTER();
1197
1198 if (!is_sync_kiocb(kiocb)) {
1199 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1200 if (!p)
1201 return -ENOMEM;
1202 p->aio = true;
1203 } else {
1204 memset(p, 0, sizeof(*p));
1205 p->aio = false;
1206 }
1207
1208 p->read = false;
1209 p->kiocb = kiocb;
1210 p->data = *from;
1211 p->mm = current->mm;
1212
1213 kiocb->private = p;
1214
1215 if (p->aio)
1216 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1217
1218 res = ffs_epfile_io(kiocb->ki_filp, p);
1219 if (res == -EIOCBQUEUED)
1220 return res;
1221 if (p->aio)
1222 kfree(p);
1223 else
1224 *from = p->data;
1225 return res;
1226 }
1227
ffs_epfile_read_iter(struct kiocb * kiocb,struct iov_iter * to)1228 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1229 {
1230 struct ffs_io_data io_data, *p = &io_data;
1231 ssize_t res;
1232
1233 ENTER();
1234
1235 if (!is_sync_kiocb(kiocb)) {
1236 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1237 if (!p)
1238 return -ENOMEM;
1239 p->aio = true;
1240 } else {
1241 memset(p, 0, sizeof(*p));
1242 p->aio = false;
1243 }
1244
1245 p->read = true;
1246 p->kiocb = kiocb;
1247 if (p->aio) {
1248 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1249 if (!p->to_free) {
1250 kfree(p);
1251 return -ENOMEM;
1252 }
1253 } else {
1254 p->data = *to;
1255 p->to_free = NULL;
1256 }
1257 p->mm = current->mm;
1258
1259 kiocb->private = p;
1260
1261 if (p->aio)
1262 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1263
1264 res = ffs_epfile_io(kiocb->ki_filp, p);
1265 if (res == -EIOCBQUEUED)
1266 return res;
1267
1268 if (p->aio) {
1269 kfree(p->to_free);
1270 kfree(p);
1271 } else {
1272 *to = p->data;
1273 }
1274 return res;
1275 }
1276
1277 static int
ffs_epfile_release(struct inode * inode,struct file * file)1278 ffs_epfile_release(struct inode *inode, struct file *file)
1279 {
1280 struct ffs_epfile *epfile = inode->i_private;
1281
1282 ENTER();
1283
1284 __ffs_epfile_read_buffer_free(epfile);
1285 ffs_data_closed(epfile->ffs);
1286
1287 return 0;
1288 }
1289
ffs_epfile_ioctl(struct file * file,unsigned code,unsigned long value)1290 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1291 unsigned long value)
1292 {
1293 struct ffs_epfile *epfile = file->private_data;
1294 struct ffs_ep *ep;
1295 int ret;
1296
1297 ENTER();
1298
1299 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1300 return -ENODEV;
1301
1302 /* Wait for endpoint to be enabled */
1303 ep = epfile->ep;
1304 if (!ep) {
1305 if (file->f_flags & O_NONBLOCK)
1306 return -EAGAIN;
1307
1308 ret = wait_event_interruptible(
1309 epfile->ffs->wait, (ep = epfile->ep));
1310 if (ret)
1311 return -EINTR;
1312 }
1313
1314 spin_lock_irq(&epfile->ffs->eps_lock);
1315
1316 /* In the meantime, endpoint got disabled or changed. */
1317 if (epfile->ep != ep) {
1318 spin_unlock_irq(&epfile->ffs->eps_lock);
1319 return -ESHUTDOWN;
1320 }
1321
1322 switch (code) {
1323 case FUNCTIONFS_FIFO_STATUS:
1324 ret = usb_ep_fifo_status(epfile->ep->ep);
1325 break;
1326 case FUNCTIONFS_FIFO_FLUSH:
1327 usb_ep_fifo_flush(epfile->ep->ep);
1328 ret = 0;
1329 break;
1330 case FUNCTIONFS_CLEAR_HALT:
1331 ret = usb_ep_clear_halt(epfile->ep->ep);
1332 break;
1333 case FUNCTIONFS_ENDPOINT_REVMAP:
1334 ret = epfile->ep->num;
1335 break;
1336 case FUNCTIONFS_ENDPOINT_DESC:
1337 {
1338 int desc_idx;
1339 struct usb_endpoint_descriptor desc1, *desc;
1340
1341 switch (epfile->ffs->gadget->speed) {
1342 case USB_SPEED_SUPER:
1343 case USB_SPEED_SUPER_PLUS:
1344 desc_idx = 2;
1345 break;
1346 case USB_SPEED_HIGH:
1347 desc_idx = 1;
1348 break;
1349 default:
1350 desc_idx = 0;
1351 }
1352
1353 desc = epfile->ep->descs[desc_idx];
1354 memcpy(&desc1, desc, desc->bLength);
1355
1356 spin_unlock_irq(&epfile->ffs->eps_lock);
1357 ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
1358 if (ret)
1359 ret = -EFAULT;
1360 return ret;
1361 }
1362 default:
1363 ret = -ENOTTY;
1364 }
1365 spin_unlock_irq(&epfile->ffs->eps_lock);
1366
1367 return ret;
1368 }
1369
1370 static const struct file_operations ffs_epfile_operations = {
1371 .llseek = no_llseek,
1372
1373 .open = ffs_epfile_open,
1374 .write_iter = ffs_epfile_write_iter,
1375 .read_iter = ffs_epfile_read_iter,
1376 .release = ffs_epfile_release,
1377 .unlocked_ioctl = ffs_epfile_ioctl,
1378 .compat_ioctl = compat_ptr_ioctl,
1379 };
1380
1381
1382 /* File system and super block operations ***********************************/
1383
1384 /*
1385 * Mounting the file system creates a controller file, used first for
1386 * function configuration then later for event monitoring.
1387 */
1388
1389 static struct inode *__must_check
ffs_sb_make_inode(struct super_block * sb,void * data,const struct file_operations * fops,const struct inode_operations * iops,struct ffs_file_perms * perms)1390 ffs_sb_make_inode(struct super_block *sb, void *data,
1391 const struct file_operations *fops,
1392 const struct inode_operations *iops,
1393 struct ffs_file_perms *perms)
1394 {
1395 struct inode *inode;
1396
1397 ENTER();
1398
1399 inode = new_inode(sb);
1400
1401 if (inode) {
1402 struct timespec64 ts = current_time(inode);
1403
1404 inode->i_ino = get_next_ino();
1405 inode->i_mode = perms->mode;
1406 inode->i_uid = perms->uid;
1407 inode->i_gid = perms->gid;
1408 inode->i_atime = ts;
1409 inode->i_mtime = ts;
1410 inode->i_ctime = ts;
1411 inode->i_private = data;
1412 if (fops)
1413 inode->i_fop = fops;
1414 if (iops)
1415 inode->i_op = iops;
1416 }
1417
1418 return inode;
1419 }
1420
1421 /* Create "regular" file */
ffs_sb_create_file(struct super_block * sb,const char * name,void * data,const struct file_operations * fops)1422 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1423 const char *name, void *data,
1424 const struct file_operations *fops)
1425 {
1426 struct ffs_data *ffs = sb->s_fs_info;
1427 struct dentry *dentry;
1428 struct inode *inode;
1429
1430 ENTER();
1431
1432 dentry = d_alloc_name(sb->s_root, name);
1433 if (!dentry)
1434 return NULL;
1435
1436 inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1437 if (!inode) {
1438 dput(dentry);
1439 return NULL;
1440 }
1441
1442 d_add(dentry, inode);
1443 return dentry;
1444 }
1445
1446 /* Super block */
1447 static const struct super_operations ffs_sb_operations = {
1448 .statfs = simple_statfs,
1449 .drop_inode = generic_delete_inode,
1450 };
1451
1452 struct ffs_sb_fill_data {
1453 struct ffs_file_perms perms;
1454 umode_t root_mode;
1455 const char *dev_name;
1456 bool no_disconnect;
1457 struct ffs_data *ffs_data;
1458 };
1459
ffs_sb_fill(struct super_block * sb,struct fs_context * fc)1460 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1461 {
1462 struct ffs_sb_fill_data *data = fc->fs_private;
1463 struct inode *inode;
1464 struct ffs_data *ffs = data->ffs_data;
1465
1466 ENTER();
1467
1468 ffs->sb = sb;
1469 data->ffs_data = NULL;
1470 sb->s_fs_info = ffs;
1471 sb->s_blocksize = PAGE_SIZE;
1472 sb->s_blocksize_bits = PAGE_SHIFT;
1473 sb->s_magic = FUNCTIONFS_MAGIC;
1474 sb->s_op = &ffs_sb_operations;
1475 sb->s_time_gran = 1;
1476
1477 /* Root inode */
1478 data->perms.mode = data->root_mode;
1479 inode = ffs_sb_make_inode(sb, NULL,
1480 &simple_dir_operations,
1481 &simple_dir_inode_operations,
1482 &data->perms);
1483 sb->s_root = d_make_root(inode);
1484 if (!sb->s_root)
1485 return -ENOMEM;
1486
1487 /* EP0 file */
1488 if (!ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations))
1489 return -ENOMEM;
1490
1491 return 0;
1492 }
1493
1494 enum {
1495 Opt_no_disconnect,
1496 Opt_rmode,
1497 Opt_fmode,
1498 Opt_mode,
1499 Opt_uid,
1500 Opt_gid,
1501 };
1502
1503 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1504 fsparam_bool ("no_disconnect", Opt_no_disconnect),
1505 fsparam_u32 ("rmode", Opt_rmode),
1506 fsparam_u32 ("fmode", Opt_fmode),
1507 fsparam_u32 ("mode", Opt_mode),
1508 fsparam_u32 ("uid", Opt_uid),
1509 fsparam_u32 ("gid", Opt_gid),
1510 {}
1511 };
1512
ffs_fs_parse_param(struct fs_context * fc,struct fs_parameter * param)1513 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1514 {
1515 struct ffs_sb_fill_data *data = fc->fs_private;
1516 struct fs_parse_result result;
1517 int opt;
1518
1519 ENTER();
1520
1521 opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1522 if (opt < 0)
1523 return opt;
1524
1525 switch (opt) {
1526 case Opt_no_disconnect:
1527 data->no_disconnect = result.boolean;
1528 break;
1529 case Opt_rmode:
1530 data->root_mode = (result.uint_32 & 0555) | S_IFDIR;
1531 break;
1532 case Opt_fmode:
1533 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1534 break;
1535 case Opt_mode:
1536 data->root_mode = (result.uint_32 & 0555) | S_IFDIR;
1537 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1538 break;
1539
1540 case Opt_uid:
1541 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1542 if (!uid_valid(data->perms.uid))
1543 goto unmapped_value;
1544 break;
1545 case Opt_gid:
1546 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1547 if (!gid_valid(data->perms.gid))
1548 goto unmapped_value;
1549 break;
1550
1551 default:
1552 return -ENOPARAM;
1553 }
1554
1555 return 0;
1556
1557 unmapped_value:
1558 return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1559 }
1560
1561 /*
1562 * Set up the superblock for a mount.
1563 */
ffs_fs_get_tree(struct fs_context * fc)1564 static int ffs_fs_get_tree(struct fs_context *fc)
1565 {
1566 struct ffs_sb_fill_data *ctx = fc->fs_private;
1567 struct ffs_data *ffs;
1568 int ret;
1569
1570 ENTER();
1571
1572 if (!fc->source)
1573 return invalf(fc, "No source specified");
1574
1575 ffs = ffs_data_new(fc->source);
1576 if (!ffs)
1577 return -ENOMEM;
1578 ffs->file_perms = ctx->perms;
1579 ffs->no_disconnect = ctx->no_disconnect;
1580
1581 ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1582 if (!ffs->dev_name) {
1583 ffs_data_put(ffs);
1584 return -ENOMEM;
1585 }
1586
1587 ret = ffs_acquire_dev(ffs->dev_name, ffs);
1588 if (ret) {
1589 ffs_data_put(ffs);
1590 return ret;
1591 }
1592
1593 ctx->ffs_data = ffs;
1594 return get_tree_nodev(fc, ffs_sb_fill);
1595 }
1596
ffs_fs_free_fc(struct fs_context * fc)1597 static void ffs_fs_free_fc(struct fs_context *fc)
1598 {
1599 struct ffs_sb_fill_data *ctx = fc->fs_private;
1600
1601 if (ctx) {
1602 if (ctx->ffs_data) {
1603 ffs_data_put(ctx->ffs_data);
1604 }
1605
1606 kfree(ctx);
1607 }
1608 }
1609
1610 static const struct fs_context_operations ffs_fs_context_ops = {
1611 .free = ffs_fs_free_fc,
1612 .parse_param = ffs_fs_parse_param,
1613 .get_tree = ffs_fs_get_tree,
1614 };
1615
ffs_fs_init_fs_context(struct fs_context * fc)1616 static int ffs_fs_init_fs_context(struct fs_context *fc)
1617 {
1618 struct ffs_sb_fill_data *ctx;
1619
1620 ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1621 if (!ctx)
1622 return -ENOMEM;
1623
1624 ctx->perms.mode = S_IFREG | 0600;
1625 ctx->perms.uid = GLOBAL_ROOT_UID;
1626 ctx->perms.gid = GLOBAL_ROOT_GID;
1627 ctx->root_mode = S_IFDIR | 0500;
1628 ctx->no_disconnect = false;
1629
1630 fc->fs_private = ctx;
1631 fc->ops = &ffs_fs_context_ops;
1632 return 0;
1633 }
1634
1635 static void
ffs_fs_kill_sb(struct super_block * sb)1636 ffs_fs_kill_sb(struct super_block *sb)
1637 {
1638 ENTER();
1639
1640 kill_litter_super(sb);
1641 if (sb->s_fs_info)
1642 ffs_data_closed(sb->s_fs_info);
1643 }
1644
1645 static struct file_system_type ffs_fs_type = {
1646 .owner = THIS_MODULE,
1647 .name = "functionfs",
1648 .init_fs_context = ffs_fs_init_fs_context,
1649 .parameters = ffs_fs_fs_parameters,
1650 .kill_sb = ffs_fs_kill_sb,
1651 };
1652 MODULE_ALIAS_FS("functionfs");
1653
1654
1655 /* Driver's main init/cleanup functions *************************************/
1656
functionfs_init(void)1657 static int functionfs_init(void)
1658 {
1659 int ret;
1660
1661 ENTER();
1662
1663 ret = register_filesystem(&ffs_fs_type);
1664 if (!ret)
1665 pr_info("file system registered\n");
1666 else
1667 pr_err("failed registering file system (%d)\n", ret);
1668
1669 return ret;
1670 }
1671
functionfs_cleanup(void)1672 static void functionfs_cleanup(void)
1673 {
1674 ENTER();
1675
1676 pr_info("unloading\n");
1677 unregister_filesystem(&ffs_fs_type);
1678 }
1679
1680
1681 /* ffs_data and ffs_function construction and destruction code **************/
1682
1683 static void ffs_data_clear(struct ffs_data *ffs);
1684 static void ffs_data_reset(struct ffs_data *ffs);
1685
ffs_data_get(struct ffs_data * ffs)1686 static void ffs_data_get(struct ffs_data *ffs)
1687 {
1688 ENTER();
1689
1690 refcount_inc(&ffs->ref);
1691 }
1692
ffs_data_opened(struct ffs_data * ffs)1693 static void ffs_data_opened(struct ffs_data *ffs)
1694 {
1695 ENTER();
1696
1697 refcount_inc(&ffs->ref);
1698 if (atomic_add_return(1, &ffs->opened) == 1 &&
1699 ffs->state == FFS_DEACTIVATED) {
1700 ffs->state = FFS_CLOSING;
1701 ffs_data_reset(ffs);
1702 }
1703 }
1704
ffs_data_put(struct ffs_data * ffs)1705 static void ffs_data_put(struct ffs_data *ffs)
1706 {
1707 ENTER();
1708
1709 if (refcount_dec_and_test(&ffs->ref)) {
1710 pr_info("%s(): freeing\n", __func__);
1711 ffs_data_clear(ffs);
1712 ffs_release_dev(ffs->private_data);
1713 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1714 swait_active(&ffs->ep0req_completion.wait) ||
1715 waitqueue_active(&ffs->wait));
1716 destroy_workqueue(ffs->io_completion_wq);
1717 kfree(ffs->dev_name);
1718 kfree(ffs);
1719 }
1720 }
1721
ffs_data_closed(struct ffs_data * ffs)1722 static void ffs_data_closed(struct ffs_data *ffs)
1723 {
1724 struct ffs_epfile *epfiles;
1725 unsigned long flags;
1726
1727 ENTER();
1728
1729 if (atomic_dec_and_test(&ffs->opened)) {
1730 if (ffs->no_disconnect) {
1731 ffs->state = FFS_DEACTIVATED;
1732 spin_lock_irqsave(&ffs->eps_lock, flags);
1733 epfiles = ffs->epfiles;
1734 ffs->epfiles = NULL;
1735 spin_unlock_irqrestore(&ffs->eps_lock,
1736 flags);
1737
1738 if (epfiles)
1739 ffs_epfiles_destroy(epfiles,
1740 ffs->eps_count);
1741
1742 if (ffs->setup_state == FFS_SETUP_PENDING)
1743 __ffs_ep0_stall(ffs);
1744 } else {
1745 ffs->state = FFS_CLOSING;
1746 ffs_data_reset(ffs);
1747 }
1748 }
1749 if (atomic_read(&ffs->opened) < 0) {
1750 ffs->state = FFS_CLOSING;
1751 ffs_data_reset(ffs);
1752 }
1753
1754 ffs_data_put(ffs);
1755 }
1756
ffs_data_new(const char * dev_name)1757 static struct ffs_data *ffs_data_new(const char *dev_name)
1758 {
1759 struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1760 if (!ffs)
1761 return NULL;
1762
1763 ENTER();
1764
1765 ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1766 if (!ffs->io_completion_wq) {
1767 kfree(ffs);
1768 return NULL;
1769 }
1770
1771 refcount_set(&ffs->ref, 1);
1772 atomic_set(&ffs->opened, 0);
1773 ffs->state = FFS_READ_DESCRIPTORS;
1774 mutex_init(&ffs->mutex);
1775 spin_lock_init(&ffs->eps_lock);
1776 init_waitqueue_head(&ffs->ev.waitq);
1777 init_waitqueue_head(&ffs->wait);
1778 init_completion(&ffs->ep0req_completion);
1779
1780 /* XXX REVISIT need to update it in some places, or do we? */
1781 ffs->ev.can_stall = 1;
1782
1783 return ffs;
1784 }
1785
ffs_data_clear(struct ffs_data * ffs)1786 static void ffs_data_clear(struct ffs_data *ffs)
1787 {
1788 struct ffs_epfile *epfiles;
1789 unsigned long flags;
1790
1791 ENTER();
1792
1793 ffs_closed(ffs);
1794
1795 BUG_ON(ffs->gadget);
1796
1797 spin_lock_irqsave(&ffs->eps_lock, flags);
1798 epfiles = ffs->epfiles;
1799 ffs->epfiles = NULL;
1800 spin_unlock_irqrestore(&ffs->eps_lock, flags);
1801
1802 /*
1803 * potential race possible between ffs_func_eps_disable
1804 * & ffs_epfile_release therefore maintaining a local
1805 * copy of epfile will save us from use-after-free.
1806 */
1807 if (epfiles) {
1808 ffs_epfiles_destroy(epfiles, ffs->eps_count);
1809 ffs->epfiles = NULL;
1810 }
1811
1812 if (ffs->ffs_eventfd) {
1813 eventfd_ctx_put(ffs->ffs_eventfd);
1814 ffs->ffs_eventfd = NULL;
1815 }
1816
1817 kfree(ffs->raw_descs_data);
1818 kfree(ffs->raw_strings);
1819 kfree(ffs->stringtabs);
1820 }
1821
ffs_data_reset(struct ffs_data * ffs)1822 static void ffs_data_reset(struct ffs_data *ffs)
1823 {
1824 ENTER();
1825
1826 ffs_data_clear(ffs);
1827
1828 ffs->raw_descs_data = NULL;
1829 ffs->raw_descs = NULL;
1830 ffs->raw_strings = NULL;
1831 ffs->stringtabs = NULL;
1832
1833 ffs->raw_descs_length = 0;
1834 ffs->fs_descs_count = 0;
1835 ffs->hs_descs_count = 0;
1836 ffs->ss_descs_count = 0;
1837
1838 ffs->strings_count = 0;
1839 ffs->interfaces_count = 0;
1840 ffs->eps_count = 0;
1841
1842 ffs->ev.count = 0;
1843
1844 ffs->state = FFS_READ_DESCRIPTORS;
1845 ffs->setup_state = FFS_NO_SETUP;
1846 ffs->flags = 0;
1847
1848 ffs->ms_os_descs_ext_prop_count = 0;
1849 ffs->ms_os_descs_ext_prop_name_len = 0;
1850 ffs->ms_os_descs_ext_prop_data_len = 0;
1851 }
1852
1853
functionfs_bind(struct ffs_data * ffs,struct usb_composite_dev * cdev)1854 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1855 {
1856 struct usb_gadget_strings **lang;
1857 int first_id;
1858
1859 ENTER();
1860
1861 if (WARN_ON(ffs->state != FFS_ACTIVE
1862 || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1863 return -EBADFD;
1864
1865 first_id = usb_string_ids_n(cdev, ffs->strings_count);
1866 if (first_id < 0)
1867 return first_id;
1868
1869 ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1870 if (!ffs->ep0req)
1871 return -ENOMEM;
1872 ffs->ep0req->complete = ffs_ep0_complete;
1873 ffs->ep0req->context = ffs;
1874
1875 lang = ffs->stringtabs;
1876 if (lang) {
1877 for (; *lang; ++lang) {
1878 struct usb_string *str = (*lang)->strings;
1879 int id = first_id;
1880 for (; str->s; ++id, ++str)
1881 str->id = id;
1882 }
1883 }
1884
1885 ffs->gadget = cdev->gadget;
1886 ffs_data_get(ffs);
1887 return 0;
1888 }
1889
functionfs_unbind(struct ffs_data * ffs)1890 static void functionfs_unbind(struct ffs_data *ffs)
1891 {
1892 ENTER();
1893
1894 if (!WARN_ON(!ffs->gadget)) {
1895 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1896 ffs->ep0req = NULL;
1897 ffs->gadget = NULL;
1898 clear_bit(FFS_FL_BOUND, &ffs->flags);
1899 ffs_data_put(ffs);
1900 }
1901 }
1902
ffs_epfiles_create(struct ffs_data * ffs)1903 static int ffs_epfiles_create(struct ffs_data *ffs)
1904 {
1905 struct ffs_epfile *epfile, *epfiles;
1906 unsigned i, count;
1907
1908 ENTER();
1909
1910 count = ffs->eps_count;
1911 epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1912 if (!epfiles)
1913 return -ENOMEM;
1914
1915 epfile = epfiles;
1916 for (i = 1; i <= count; ++i, ++epfile) {
1917 epfile->ffs = ffs;
1918 mutex_init(&epfile->mutex);
1919 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1920 sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1921 else
1922 sprintf(epfile->name, "ep%u", i);
1923 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1924 epfile,
1925 &ffs_epfile_operations);
1926 if (!epfile->dentry) {
1927 ffs_epfiles_destroy(epfiles, i - 1);
1928 return -ENOMEM;
1929 }
1930 }
1931
1932 ffs->epfiles = epfiles;
1933 return 0;
1934 }
1935
ffs_epfiles_destroy(struct ffs_epfile * epfiles,unsigned count)1936 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1937 {
1938 struct ffs_epfile *epfile = epfiles;
1939
1940 ENTER();
1941
1942 for (; count; --count, ++epfile) {
1943 BUG_ON(mutex_is_locked(&epfile->mutex));
1944 if (epfile->dentry) {
1945 d_delete(epfile->dentry);
1946 dput(epfile->dentry);
1947 epfile->dentry = NULL;
1948 }
1949 }
1950
1951 kfree(epfiles);
1952 }
1953
ffs_func_eps_disable(struct ffs_function * func)1954 static void ffs_func_eps_disable(struct ffs_function *func)
1955 {
1956 struct ffs_ep *ep;
1957 struct ffs_epfile *epfile;
1958 unsigned short count;
1959 unsigned long flags;
1960
1961 spin_lock_irqsave(&func->ffs->eps_lock, flags);
1962 count = func->ffs->eps_count;
1963 epfile = func->ffs->epfiles;
1964 ep = func->eps;
1965 while (count--) {
1966 /* pending requests get nuked */
1967 if (ep->ep)
1968 usb_ep_disable(ep->ep);
1969 ++ep;
1970
1971 if (epfile) {
1972 epfile->ep = NULL;
1973 __ffs_epfile_read_buffer_free(epfile);
1974 ++epfile;
1975 }
1976 }
1977 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1978 }
1979
ffs_func_eps_enable(struct ffs_function * func)1980 static int ffs_func_eps_enable(struct ffs_function *func)
1981 {
1982 struct ffs_data *ffs;
1983 struct ffs_ep *ep;
1984 struct ffs_epfile *epfile;
1985 unsigned short count;
1986 unsigned long flags;
1987 int ret = 0;
1988
1989 spin_lock_irqsave(&func->ffs->eps_lock, flags);
1990 ffs = func->ffs;
1991 ep = func->eps;
1992 epfile = ffs->epfiles;
1993 count = ffs->eps_count;
1994 while(count--) {
1995 ep->ep->driver_data = ep;
1996
1997 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1998 if (ret) {
1999 pr_err("%s: config_ep_by_speed(%s) returned %d\n",
2000 __func__, ep->ep->name, ret);
2001 break;
2002 }
2003
2004 ret = usb_ep_enable(ep->ep);
2005 if (!ret) {
2006 epfile->ep = ep;
2007 epfile->in = usb_endpoint_dir_in(ep->ep->desc);
2008 epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
2009 } else {
2010 break;
2011 }
2012
2013 ++ep;
2014 ++epfile;
2015 }
2016
2017 wake_up_interruptible(&ffs->wait);
2018 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2019
2020 return ret;
2021 }
2022
2023
2024 /* Parsing and building descriptors and strings *****************************/
2025
2026 /*
2027 * This validates if data pointed by data is a valid USB descriptor as
2028 * well as record how many interfaces, endpoints and strings are
2029 * required by given configuration. Returns address after the
2030 * descriptor or NULL if data is invalid.
2031 */
2032
2033 enum ffs_entity_type {
2034 FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
2035 };
2036
2037 enum ffs_os_desc_type {
2038 FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
2039 };
2040
2041 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2042 u8 *valuep,
2043 struct usb_descriptor_header *desc,
2044 void *priv);
2045
2046 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2047 struct usb_os_desc_header *h, void *data,
2048 unsigned len, void *priv);
2049
ffs_do_single_desc(char * data,unsigned len,ffs_entity_callback entity,void * priv,int * current_class)2050 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2051 ffs_entity_callback entity,
2052 void *priv, int *current_class)
2053 {
2054 struct usb_descriptor_header *_ds = (void *)data;
2055 u8 length;
2056 int ret;
2057
2058 ENTER();
2059
2060 /* At least two bytes are required: length and type */
2061 if (len < 2) {
2062 pr_vdebug("descriptor too short\n");
2063 return -EINVAL;
2064 }
2065
2066 /* If we have at least as many bytes as the descriptor takes? */
2067 length = _ds->bLength;
2068 if (len < length) {
2069 pr_vdebug("descriptor longer then available data\n");
2070 return -EINVAL;
2071 }
2072
2073 #define __entity_check_INTERFACE(val) 1
2074 #define __entity_check_STRING(val) (val)
2075 #define __entity_check_ENDPOINT(val) ((val) & USB_ENDPOINT_NUMBER_MASK)
2076 #define __entity(type, val) do { \
2077 pr_vdebug("entity " #type "(%02x)\n", (val)); \
2078 if (!__entity_check_ ##type(val)) { \
2079 pr_vdebug("invalid entity's value\n"); \
2080 return -EINVAL; \
2081 } \
2082 ret = entity(FFS_ ##type, &val, _ds, priv); \
2083 if (ret < 0) { \
2084 pr_debug("entity " #type "(%02x); ret = %d\n", \
2085 (val), ret); \
2086 return ret; \
2087 } \
2088 } while (0)
2089
2090 /* Parse descriptor depending on type. */
2091 switch (_ds->bDescriptorType) {
2092 case USB_DT_DEVICE:
2093 case USB_DT_CONFIG:
2094 case USB_DT_STRING:
2095 case USB_DT_DEVICE_QUALIFIER:
2096 /* function can't have any of those */
2097 pr_vdebug("descriptor reserved for gadget: %d\n",
2098 _ds->bDescriptorType);
2099 return -EINVAL;
2100
2101 case USB_DT_INTERFACE: {
2102 struct usb_interface_descriptor *ds = (void *)_ds;
2103 pr_vdebug("interface descriptor\n");
2104 if (length != sizeof *ds)
2105 goto inv_length;
2106
2107 __entity(INTERFACE, ds->bInterfaceNumber);
2108 if (ds->iInterface)
2109 __entity(STRING, ds->iInterface);
2110 *current_class = ds->bInterfaceClass;
2111 }
2112 break;
2113
2114 case USB_DT_ENDPOINT: {
2115 struct usb_endpoint_descriptor *ds = (void *)_ds;
2116 pr_vdebug("endpoint descriptor\n");
2117 if (length != USB_DT_ENDPOINT_SIZE &&
2118 length != USB_DT_ENDPOINT_AUDIO_SIZE)
2119 goto inv_length;
2120 __entity(ENDPOINT, ds->bEndpointAddress);
2121 }
2122 break;
2123
2124 case USB_TYPE_CLASS | 0x01:
2125 if (*current_class == USB_INTERFACE_CLASS_HID) {
2126 pr_vdebug("hid descriptor\n");
2127 if (length != sizeof(struct hid_descriptor))
2128 goto inv_length;
2129 break;
2130 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2131 pr_vdebug("ccid descriptor\n");
2132 if (length != sizeof(struct ccid_descriptor))
2133 goto inv_length;
2134 break;
2135 } else {
2136 pr_vdebug("unknown descriptor: %d for class %d\n",
2137 _ds->bDescriptorType, *current_class);
2138 return -EINVAL;
2139 }
2140
2141 case USB_DT_OTG:
2142 if (length != sizeof(struct usb_otg_descriptor))
2143 goto inv_length;
2144 break;
2145
2146 case USB_DT_INTERFACE_ASSOCIATION: {
2147 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2148 pr_vdebug("interface association descriptor\n");
2149 if (length != sizeof *ds)
2150 goto inv_length;
2151 if (ds->iFunction)
2152 __entity(STRING, ds->iFunction);
2153 }
2154 break;
2155
2156 case USB_DT_SS_ENDPOINT_COMP:
2157 pr_vdebug("EP SS companion descriptor\n");
2158 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2159 goto inv_length;
2160 break;
2161
2162 case USB_DT_OTHER_SPEED_CONFIG:
2163 case USB_DT_INTERFACE_POWER:
2164 case USB_DT_DEBUG:
2165 case USB_DT_SECURITY:
2166 case USB_DT_CS_RADIO_CONTROL:
2167 /* TODO */
2168 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2169 return -EINVAL;
2170
2171 default:
2172 /* We should never be here */
2173 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2174 return -EINVAL;
2175
2176 inv_length:
2177 pr_vdebug("invalid length: %d (descriptor %d)\n",
2178 _ds->bLength, _ds->bDescriptorType);
2179 return -EINVAL;
2180 }
2181
2182 #undef __entity
2183 #undef __entity_check_DESCRIPTOR
2184 #undef __entity_check_INTERFACE
2185 #undef __entity_check_STRING
2186 #undef __entity_check_ENDPOINT
2187
2188 return length;
2189 }
2190
ffs_do_descs(unsigned count,char * data,unsigned len,ffs_entity_callback entity,void * priv)2191 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2192 ffs_entity_callback entity, void *priv)
2193 {
2194 const unsigned _len = len;
2195 unsigned long num = 0;
2196 int current_class = -1;
2197
2198 ENTER();
2199
2200 for (;;) {
2201 int ret;
2202
2203 if (num == count)
2204 data = NULL;
2205
2206 /* Record "descriptor" entity */
2207 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2208 if (ret < 0) {
2209 pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2210 num, ret);
2211 return ret;
2212 }
2213
2214 if (!data)
2215 return _len - len;
2216
2217 ret = ffs_do_single_desc(data, len, entity, priv,
2218 ¤t_class);
2219 if (ret < 0) {
2220 pr_debug("%s returns %d\n", __func__, ret);
2221 return ret;
2222 }
2223
2224 len -= ret;
2225 data += ret;
2226 ++num;
2227 }
2228 }
2229
__ffs_data_do_entity(enum ffs_entity_type type,u8 * valuep,struct usb_descriptor_header * desc,void * priv)2230 static int __ffs_data_do_entity(enum ffs_entity_type type,
2231 u8 *valuep, struct usb_descriptor_header *desc,
2232 void *priv)
2233 {
2234 struct ffs_desc_helper *helper = priv;
2235 struct usb_endpoint_descriptor *d;
2236
2237 ENTER();
2238
2239 switch (type) {
2240 case FFS_DESCRIPTOR:
2241 break;
2242
2243 case FFS_INTERFACE:
2244 /*
2245 * Interfaces are indexed from zero so if we
2246 * encountered interface "n" then there are at least
2247 * "n+1" interfaces.
2248 */
2249 if (*valuep >= helper->interfaces_count)
2250 helper->interfaces_count = *valuep + 1;
2251 break;
2252
2253 case FFS_STRING:
2254 /*
2255 * Strings are indexed from 1 (0 is reserved
2256 * for languages list)
2257 */
2258 if (*valuep > helper->ffs->strings_count)
2259 helper->ffs->strings_count = *valuep;
2260 break;
2261
2262 case FFS_ENDPOINT:
2263 d = (void *)desc;
2264 helper->eps_count++;
2265 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2266 return -EINVAL;
2267 /* Check if descriptors for any speed were already parsed */
2268 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2269 helper->ffs->eps_addrmap[helper->eps_count] =
2270 d->bEndpointAddress;
2271 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2272 d->bEndpointAddress)
2273 return -EINVAL;
2274 break;
2275 }
2276
2277 return 0;
2278 }
2279
__ffs_do_os_desc_header(enum ffs_os_desc_type * next_type,struct usb_os_desc_header * desc)2280 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2281 struct usb_os_desc_header *desc)
2282 {
2283 u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2284 u16 w_index = le16_to_cpu(desc->wIndex);
2285
2286 if (bcd_version != 1) {
2287 pr_vdebug("unsupported os descriptors version: %d",
2288 bcd_version);
2289 return -EINVAL;
2290 }
2291 switch (w_index) {
2292 case 0x4:
2293 *next_type = FFS_OS_DESC_EXT_COMPAT;
2294 break;
2295 case 0x5:
2296 *next_type = FFS_OS_DESC_EXT_PROP;
2297 break;
2298 default:
2299 pr_vdebug("unsupported os descriptor type: %d", w_index);
2300 return -EINVAL;
2301 }
2302
2303 return sizeof(*desc);
2304 }
2305
2306 /*
2307 * Process all extended compatibility/extended property descriptors
2308 * of a feature descriptor
2309 */
ffs_do_single_os_desc(char * data,unsigned len,enum ffs_os_desc_type type,u16 feature_count,ffs_os_desc_callback entity,void * priv,struct usb_os_desc_header * h)2310 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2311 enum ffs_os_desc_type type,
2312 u16 feature_count,
2313 ffs_os_desc_callback entity,
2314 void *priv,
2315 struct usb_os_desc_header *h)
2316 {
2317 int ret;
2318 const unsigned _len = len;
2319
2320 ENTER();
2321
2322 /* loop over all ext compat/ext prop descriptors */
2323 while (feature_count--) {
2324 ret = entity(type, h, data, len, priv);
2325 if (ret < 0) {
2326 pr_debug("bad OS descriptor, type: %d\n", type);
2327 return ret;
2328 }
2329 data += ret;
2330 len -= ret;
2331 }
2332 return _len - len;
2333 }
2334
2335 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
ffs_do_os_descs(unsigned count,char * data,unsigned len,ffs_os_desc_callback entity,void * priv)2336 static int __must_check ffs_do_os_descs(unsigned count,
2337 char *data, unsigned len,
2338 ffs_os_desc_callback entity, void *priv)
2339 {
2340 const unsigned _len = len;
2341 unsigned long num = 0;
2342
2343 ENTER();
2344
2345 for (num = 0; num < count; ++num) {
2346 int ret;
2347 enum ffs_os_desc_type type;
2348 u16 feature_count;
2349 struct usb_os_desc_header *desc = (void *)data;
2350
2351 if (len < sizeof(*desc))
2352 return -EINVAL;
2353
2354 /*
2355 * Record "descriptor" entity.
2356 * Process dwLength, bcdVersion, wIndex, get b/wCount.
2357 * Move the data pointer to the beginning of extended
2358 * compatibilities proper or extended properties proper
2359 * portions of the data
2360 */
2361 if (le32_to_cpu(desc->dwLength) > len)
2362 return -EINVAL;
2363
2364 ret = __ffs_do_os_desc_header(&type, desc);
2365 if (ret < 0) {
2366 pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2367 num, ret);
2368 return ret;
2369 }
2370 /*
2371 * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2372 */
2373 feature_count = le16_to_cpu(desc->wCount);
2374 if (type == FFS_OS_DESC_EXT_COMPAT &&
2375 (feature_count > 255 || desc->Reserved))
2376 return -EINVAL;
2377 len -= ret;
2378 data += ret;
2379
2380 /*
2381 * Process all function/property descriptors
2382 * of this Feature Descriptor
2383 */
2384 ret = ffs_do_single_os_desc(data, len, type,
2385 feature_count, entity, priv, desc);
2386 if (ret < 0) {
2387 pr_debug("%s returns %d\n", __func__, ret);
2388 return ret;
2389 }
2390
2391 len -= ret;
2392 data += ret;
2393 }
2394 return _len - len;
2395 }
2396
2397 /*
2398 * Validate contents of the buffer from userspace related to OS descriptors.
2399 */
__ffs_data_do_os_desc(enum ffs_os_desc_type type,struct usb_os_desc_header * h,void * data,unsigned len,void * priv)2400 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2401 struct usb_os_desc_header *h, void *data,
2402 unsigned len, void *priv)
2403 {
2404 struct ffs_data *ffs = priv;
2405 u8 length;
2406
2407 ENTER();
2408
2409 switch (type) {
2410 case FFS_OS_DESC_EXT_COMPAT: {
2411 struct usb_ext_compat_desc *d = data;
2412 int i;
2413
2414 if (len < sizeof(*d) ||
2415 d->bFirstInterfaceNumber >= ffs->interfaces_count)
2416 return -EINVAL;
2417 if (d->Reserved1 != 1) {
2418 /*
2419 * According to the spec, Reserved1 must be set to 1
2420 * but older kernels incorrectly rejected non-zero
2421 * values. We fix it here to avoid returning EINVAL
2422 * in response to values we used to accept.
2423 */
2424 pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2425 d->Reserved1 = 1;
2426 }
2427 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2428 if (d->Reserved2[i])
2429 return -EINVAL;
2430
2431 length = sizeof(struct usb_ext_compat_desc);
2432 }
2433 break;
2434 case FFS_OS_DESC_EXT_PROP: {
2435 struct usb_ext_prop_desc *d = data;
2436 u32 type, pdl;
2437 u16 pnl;
2438
2439 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2440 return -EINVAL;
2441 length = le32_to_cpu(d->dwSize);
2442 if (len < length)
2443 return -EINVAL;
2444 type = le32_to_cpu(d->dwPropertyDataType);
2445 if (type < USB_EXT_PROP_UNICODE ||
2446 type > USB_EXT_PROP_UNICODE_MULTI) {
2447 pr_vdebug("unsupported os descriptor property type: %d",
2448 type);
2449 return -EINVAL;
2450 }
2451 pnl = le16_to_cpu(d->wPropertyNameLength);
2452 if (length < 14 + pnl) {
2453 pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2454 length, pnl, type);
2455 return -EINVAL;
2456 }
2457 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2458 if (length != 14 + pnl + pdl) {
2459 pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2460 length, pnl, pdl, type);
2461 return -EINVAL;
2462 }
2463 ++ffs->ms_os_descs_ext_prop_count;
2464 /* property name reported to the host as "WCHAR"s */
2465 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2466 ffs->ms_os_descs_ext_prop_data_len += pdl;
2467 }
2468 break;
2469 default:
2470 pr_vdebug("unknown descriptor: %d\n", type);
2471 return -EINVAL;
2472 }
2473 return length;
2474 }
2475
__ffs_data_got_descs(struct ffs_data * ffs,char * const _data,size_t len)2476 static int __ffs_data_got_descs(struct ffs_data *ffs,
2477 char *const _data, size_t len)
2478 {
2479 char *data = _data, *raw_descs;
2480 unsigned os_descs_count = 0, counts[3], flags;
2481 int ret = -EINVAL, i;
2482 struct ffs_desc_helper helper;
2483
2484 ENTER();
2485
2486 if (get_unaligned_le32(data + 4) != len)
2487 goto error;
2488
2489 switch (get_unaligned_le32(data)) {
2490 case FUNCTIONFS_DESCRIPTORS_MAGIC:
2491 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2492 data += 8;
2493 len -= 8;
2494 break;
2495 case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2496 flags = get_unaligned_le32(data + 8);
2497 ffs->user_flags = flags;
2498 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2499 FUNCTIONFS_HAS_HS_DESC |
2500 FUNCTIONFS_HAS_SS_DESC |
2501 FUNCTIONFS_HAS_MS_OS_DESC |
2502 FUNCTIONFS_VIRTUAL_ADDR |
2503 FUNCTIONFS_EVENTFD |
2504 FUNCTIONFS_ALL_CTRL_RECIP |
2505 FUNCTIONFS_CONFIG0_SETUP)) {
2506 ret = -ENOSYS;
2507 goto error;
2508 }
2509 data += 12;
2510 len -= 12;
2511 break;
2512 default:
2513 goto error;
2514 }
2515
2516 if (flags & FUNCTIONFS_EVENTFD) {
2517 if (len < 4)
2518 goto error;
2519 ffs->ffs_eventfd =
2520 eventfd_ctx_fdget((int)get_unaligned_le32(data));
2521 if (IS_ERR(ffs->ffs_eventfd)) {
2522 ret = PTR_ERR(ffs->ffs_eventfd);
2523 ffs->ffs_eventfd = NULL;
2524 goto error;
2525 }
2526 data += 4;
2527 len -= 4;
2528 }
2529
2530 /* Read fs_count, hs_count and ss_count (if present) */
2531 for (i = 0; i < 3; ++i) {
2532 if (!(flags & (1 << i))) {
2533 counts[i] = 0;
2534 } else if (len < 4) {
2535 goto error;
2536 } else {
2537 counts[i] = get_unaligned_le32(data);
2538 data += 4;
2539 len -= 4;
2540 }
2541 }
2542 if (flags & (1 << i)) {
2543 if (len < 4) {
2544 goto error;
2545 }
2546 os_descs_count = get_unaligned_le32(data);
2547 data += 4;
2548 len -= 4;
2549 }
2550
2551 /* Read descriptors */
2552 raw_descs = data;
2553 helper.ffs = ffs;
2554 for (i = 0; i < 3; ++i) {
2555 if (!counts[i])
2556 continue;
2557 helper.interfaces_count = 0;
2558 helper.eps_count = 0;
2559 ret = ffs_do_descs(counts[i], data, len,
2560 __ffs_data_do_entity, &helper);
2561 if (ret < 0)
2562 goto error;
2563 if (!ffs->eps_count && !ffs->interfaces_count) {
2564 ffs->eps_count = helper.eps_count;
2565 ffs->interfaces_count = helper.interfaces_count;
2566 } else {
2567 if (ffs->eps_count != helper.eps_count) {
2568 ret = -EINVAL;
2569 goto error;
2570 }
2571 if (ffs->interfaces_count != helper.interfaces_count) {
2572 ret = -EINVAL;
2573 goto error;
2574 }
2575 }
2576 data += ret;
2577 len -= ret;
2578 }
2579 if (os_descs_count) {
2580 ret = ffs_do_os_descs(os_descs_count, data, len,
2581 __ffs_data_do_os_desc, ffs);
2582 if (ret < 0)
2583 goto error;
2584 data += ret;
2585 len -= ret;
2586 }
2587
2588 if (raw_descs == data || len) {
2589 ret = -EINVAL;
2590 goto error;
2591 }
2592
2593 ffs->raw_descs_data = _data;
2594 ffs->raw_descs = raw_descs;
2595 ffs->raw_descs_length = data - raw_descs;
2596 ffs->fs_descs_count = counts[0];
2597 ffs->hs_descs_count = counts[1];
2598 ffs->ss_descs_count = counts[2];
2599 ffs->ms_os_descs_count = os_descs_count;
2600
2601 return 0;
2602
2603 error:
2604 kfree(_data);
2605 return ret;
2606 }
2607
__ffs_data_got_strings(struct ffs_data * ffs,char * const _data,size_t len)2608 static int __ffs_data_got_strings(struct ffs_data *ffs,
2609 char *const _data, size_t len)
2610 {
2611 u32 str_count, needed_count, lang_count;
2612 struct usb_gadget_strings **stringtabs, *t;
2613 const char *data = _data;
2614 struct usb_string *s;
2615
2616 ENTER();
2617
2618 if (len < 16 ||
2619 get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2620 get_unaligned_le32(data + 4) != len)
2621 goto error;
2622 str_count = get_unaligned_le32(data + 8);
2623 lang_count = get_unaligned_le32(data + 12);
2624
2625 /* if one is zero the other must be zero */
2626 if (!str_count != !lang_count)
2627 goto error;
2628
2629 /* Do we have at least as many strings as descriptors need? */
2630 needed_count = ffs->strings_count;
2631 if (str_count < needed_count)
2632 goto error;
2633
2634 /*
2635 * If we don't need any strings just return and free all
2636 * memory.
2637 */
2638 if (!needed_count) {
2639 kfree(_data);
2640 return 0;
2641 }
2642
2643 /* Allocate everything in one chunk so there's less maintenance. */
2644 {
2645 unsigned i = 0;
2646 vla_group(d);
2647 vla_item(d, struct usb_gadget_strings *, stringtabs,
2648 size_add(lang_count, 1));
2649 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2650 vla_item(d, struct usb_string, strings,
2651 size_mul(lang_count, (needed_count + 1)));
2652
2653 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2654
2655 if (!vlabuf) {
2656 kfree(_data);
2657 return -ENOMEM;
2658 }
2659
2660 /* Initialize the VLA pointers */
2661 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2662 t = vla_ptr(vlabuf, d, stringtab);
2663 i = lang_count;
2664 do {
2665 *stringtabs++ = t++;
2666 } while (--i);
2667 *stringtabs = NULL;
2668
2669 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2670 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2671 t = vla_ptr(vlabuf, d, stringtab);
2672 s = vla_ptr(vlabuf, d, strings);
2673 }
2674
2675 /* For each language */
2676 data += 16;
2677 len -= 16;
2678
2679 do { /* lang_count > 0 so we can use do-while */
2680 unsigned needed = needed_count;
2681 u32 str_per_lang = str_count;
2682
2683 if (len < 3)
2684 goto error_free;
2685 t->language = get_unaligned_le16(data);
2686 t->strings = s;
2687 ++t;
2688
2689 data += 2;
2690 len -= 2;
2691
2692 /* For each string */
2693 do { /* str_count > 0 so we can use do-while */
2694 size_t length = strnlen(data, len);
2695
2696 if (length == len)
2697 goto error_free;
2698
2699 /*
2700 * User may provide more strings then we need,
2701 * if that's the case we simply ignore the
2702 * rest
2703 */
2704 if (needed) {
2705 /*
2706 * s->id will be set while adding
2707 * function to configuration so for
2708 * now just leave garbage here.
2709 */
2710 s->s = data;
2711 --needed;
2712 ++s;
2713 }
2714
2715 data += length + 1;
2716 len -= length + 1;
2717 } while (--str_per_lang);
2718
2719 s->id = 0; /* terminator */
2720 s->s = NULL;
2721 ++s;
2722
2723 } while (--lang_count);
2724
2725 /* Some garbage left? */
2726 if (len)
2727 goto error_free;
2728
2729 /* Done! */
2730 ffs->stringtabs = stringtabs;
2731 ffs->raw_strings = _data;
2732
2733 return 0;
2734
2735 error_free:
2736 kfree(stringtabs);
2737 error:
2738 kfree(_data);
2739 return -EINVAL;
2740 }
2741
2742
2743 /* Events handling and management *******************************************/
2744
__ffs_event_add(struct ffs_data * ffs,enum usb_functionfs_event_type type)2745 static void __ffs_event_add(struct ffs_data *ffs,
2746 enum usb_functionfs_event_type type)
2747 {
2748 enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2749 int neg = 0;
2750
2751 /*
2752 * Abort any unhandled setup
2753 *
2754 * We do not need to worry about some cmpxchg() changing value
2755 * of ffs->setup_state without holding the lock because when
2756 * state is FFS_SETUP_PENDING cmpxchg() in several places in
2757 * the source does nothing.
2758 */
2759 if (ffs->setup_state == FFS_SETUP_PENDING)
2760 ffs->setup_state = FFS_SETUP_CANCELLED;
2761
2762 /*
2763 * Logic of this function guarantees that there are at most four pending
2764 * evens on ffs->ev.types queue. This is important because the queue
2765 * has space for four elements only and __ffs_ep0_read_events function
2766 * depends on that limit as well. If more event types are added, those
2767 * limits have to be revisited or guaranteed to still hold.
2768 */
2769 switch (type) {
2770 case FUNCTIONFS_RESUME:
2771 rem_type2 = FUNCTIONFS_SUSPEND;
2772 fallthrough;
2773 case FUNCTIONFS_SUSPEND:
2774 case FUNCTIONFS_SETUP:
2775 rem_type1 = type;
2776 /* Discard all similar events */
2777 break;
2778
2779 case FUNCTIONFS_BIND:
2780 case FUNCTIONFS_UNBIND:
2781 case FUNCTIONFS_DISABLE:
2782 case FUNCTIONFS_ENABLE:
2783 /* Discard everything other then power management. */
2784 rem_type1 = FUNCTIONFS_SUSPEND;
2785 rem_type2 = FUNCTIONFS_RESUME;
2786 neg = 1;
2787 break;
2788
2789 default:
2790 WARN(1, "%d: unknown event, this should not happen\n", type);
2791 return;
2792 }
2793
2794 {
2795 u8 *ev = ffs->ev.types, *out = ev;
2796 unsigned n = ffs->ev.count;
2797 for (; n; --n, ++ev)
2798 if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2799 *out++ = *ev;
2800 else
2801 pr_vdebug("purging event %d\n", *ev);
2802 ffs->ev.count = out - ffs->ev.types;
2803 }
2804
2805 pr_vdebug("adding event %d\n", type);
2806 ffs->ev.types[ffs->ev.count++] = type;
2807 wake_up_locked(&ffs->ev.waitq);
2808 if (ffs->ffs_eventfd)
2809 eventfd_signal(ffs->ffs_eventfd, 1);
2810 }
2811
ffs_event_add(struct ffs_data * ffs,enum usb_functionfs_event_type type)2812 static void ffs_event_add(struct ffs_data *ffs,
2813 enum usb_functionfs_event_type type)
2814 {
2815 unsigned long flags;
2816 spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2817 __ffs_event_add(ffs, type);
2818 spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2819 }
2820
2821 /* Bind/unbind USB function hooks *******************************************/
2822
ffs_ep_addr2idx(struct ffs_data * ffs,u8 endpoint_address)2823 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2824 {
2825 int i;
2826
2827 for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2828 if (ffs->eps_addrmap[i] == endpoint_address)
2829 return i;
2830 return -ENOENT;
2831 }
2832
__ffs_func_bind_do_descs(enum ffs_entity_type type,u8 * valuep,struct usb_descriptor_header * desc,void * priv)2833 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2834 struct usb_descriptor_header *desc,
2835 void *priv)
2836 {
2837 struct usb_endpoint_descriptor *ds = (void *)desc;
2838 struct ffs_function *func = priv;
2839 struct ffs_ep *ffs_ep;
2840 unsigned ep_desc_id;
2841 int idx;
2842 static const char *speed_names[] = { "full", "high", "super" };
2843
2844 if (type != FFS_DESCRIPTOR)
2845 return 0;
2846
2847 /*
2848 * If ss_descriptors is not NULL, we are reading super speed
2849 * descriptors; if hs_descriptors is not NULL, we are reading high
2850 * speed descriptors; otherwise, we are reading full speed
2851 * descriptors.
2852 */
2853 if (func->function.ss_descriptors) {
2854 ep_desc_id = 2;
2855 func->function.ss_descriptors[(long)valuep] = desc;
2856 } else if (func->function.hs_descriptors) {
2857 ep_desc_id = 1;
2858 func->function.hs_descriptors[(long)valuep] = desc;
2859 } else {
2860 ep_desc_id = 0;
2861 func->function.fs_descriptors[(long)valuep] = desc;
2862 }
2863
2864 if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2865 return 0;
2866
2867 idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2868 if (idx < 0)
2869 return idx;
2870
2871 ffs_ep = func->eps + idx;
2872
2873 if (ffs_ep->descs[ep_desc_id]) {
2874 pr_err("two %sspeed descriptors for EP %d\n",
2875 speed_names[ep_desc_id],
2876 ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2877 return -EINVAL;
2878 }
2879 ffs_ep->descs[ep_desc_id] = ds;
2880
2881 ffs_dump_mem(": Original ep desc", ds, ds->bLength);
2882 if (ffs_ep->ep) {
2883 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2884 if (!ds->wMaxPacketSize)
2885 ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2886 } else {
2887 struct usb_request *req;
2888 struct usb_ep *ep;
2889 u8 bEndpointAddress;
2890 u16 wMaxPacketSize;
2891
2892 /*
2893 * We back up bEndpointAddress because autoconfig overwrites
2894 * it with physical endpoint address.
2895 */
2896 bEndpointAddress = ds->bEndpointAddress;
2897 /*
2898 * We back up wMaxPacketSize because autoconfig treats
2899 * endpoint descriptors as if they were full speed.
2900 */
2901 wMaxPacketSize = ds->wMaxPacketSize;
2902 pr_vdebug("autoconfig\n");
2903 ep = usb_ep_autoconfig(func->gadget, ds);
2904 if (!ep)
2905 return -ENOTSUPP;
2906 ep->driver_data = func->eps + idx;
2907
2908 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2909 if (!req)
2910 return -ENOMEM;
2911
2912 ffs_ep->ep = ep;
2913 ffs_ep->req = req;
2914 func->eps_revmap[ds->bEndpointAddress &
2915 USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2916 /*
2917 * If we use virtual address mapping, we restore
2918 * original bEndpointAddress value.
2919 */
2920 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2921 ds->bEndpointAddress = bEndpointAddress;
2922 /*
2923 * Restore wMaxPacketSize which was potentially
2924 * overwritten by autoconfig.
2925 */
2926 ds->wMaxPacketSize = wMaxPacketSize;
2927 }
2928 ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2929
2930 return 0;
2931 }
2932
__ffs_func_bind_do_nums(enum ffs_entity_type type,u8 * valuep,struct usb_descriptor_header * desc,void * priv)2933 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2934 struct usb_descriptor_header *desc,
2935 void *priv)
2936 {
2937 struct ffs_function *func = priv;
2938 unsigned idx;
2939 u8 newValue;
2940
2941 switch (type) {
2942 default:
2943 case FFS_DESCRIPTOR:
2944 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2945 return 0;
2946
2947 case FFS_INTERFACE:
2948 idx = *valuep;
2949 if (func->interfaces_nums[idx] < 0) {
2950 int id = usb_interface_id(func->conf, &func->function);
2951 if (id < 0)
2952 return id;
2953 func->interfaces_nums[idx] = id;
2954 }
2955 newValue = func->interfaces_nums[idx];
2956 break;
2957
2958 case FFS_STRING:
2959 /* String' IDs are allocated when fsf_data is bound to cdev */
2960 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2961 break;
2962
2963 case FFS_ENDPOINT:
2964 /*
2965 * USB_DT_ENDPOINT are handled in
2966 * __ffs_func_bind_do_descs().
2967 */
2968 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2969 return 0;
2970
2971 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2972 if (!func->eps[idx].ep)
2973 return -EINVAL;
2974
2975 {
2976 struct usb_endpoint_descriptor **descs;
2977 descs = func->eps[idx].descs;
2978 newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2979 }
2980 break;
2981 }
2982
2983 pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2984 *valuep = newValue;
2985 return 0;
2986 }
2987
__ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,struct usb_os_desc_header * h,void * data,unsigned len,void * priv)2988 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2989 struct usb_os_desc_header *h, void *data,
2990 unsigned len, void *priv)
2991 {
2992 struct ffs_function *func = priv;
2993 u8 length = 0;
2994
2995 switch (type) {
2996 case FFS_OS_DESC_EXT_COMPAT: {
2997 struct usb_ext_compat_desc *desc = data;
2998 struct usb_os_desc_table *t;
2999
3000 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
3001 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
3002 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
3003 ARRAY_SIZE(desc->CompatibleID) +
3004 ARRAY_SIZE(desc->SubCompatibleID));
3005 length = sizeof(*desc);
3006 }
3007 break;
3008 case FFS_OS_DESC_EXT_PROP: {
3009 struct usb_ext_prop_desc *desc = data;
3010 struct usb_os_desc_table *t;
3011 struct usb_os_desc_ext_prop *ext_prop;
3012 char *ext_prop_name;
3013 char *ext_prop_data;
3014
3015 t = &func->function.os_desc_table[h->interface];
3016 t->if_id = func->interfaces_nums[h->interface];
3017
3018 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
3019 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
3020
3021 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
3022 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
3023 ext_prop->data_len = le32_to_cpu(*(__le32 *)
3024 usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
3025 length = ext_prop->name_len + ext_prop->data_len + 14;
3026
3027 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
3028 func->ffs->ms_os_descs_ext_prop_name_avail +=
3029 ext_prop->name_len;
3030
3031 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
3032 func->ffs->ms_os_descs_ext_prop_data_avail +=
3033 ext_prop->data_len;
3034 memcpy(ext_prop_data,
3035 usb_ext_prop_data_ptr(data, ext_prop->name_len),
3036 ext_prop->data_len);
3037 /* unicode data reported to the host as "WCHAR"s */
3038 switch (ext_prop->type) {
3039 case USB_EXT_PROP_UNICODE:
3040 case USB_EXT_PROP_UNICODE_ENV:
3041 case USB_EXT_PROP_UNICODE_LINK:
3042 case USB_EXT_PROP_UNICODE_MULTI:
3043 ext_prop->data_len *= 2;
3044 break;
3045 }
3046 ext_prop->data = ext_prop_data;
3047
3048 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3049 ext_prop->name_len);
3050 /* property name reported to the host as "WCHAR"s */
3051 ext_prop->name_len *= 2;
3052 ext_prop->name = ext_prop_name;
3053
3054 t->os_desc->ext_prop_len +=
3055 ext_prop->name_len + ext_prop->data_len + 14;
3056 ++t->os_desc->ext_prop_count;
3057 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3058 }
3059 break;
3060 default:
3061 pr_vdebug("unknown descriptor: %d\n", type);
3062 }
3063
3064 return length;
3065 }
3066
ffs_do_functionfs_bind(struct usb_function * f,struct usb_configuration * c)3067 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3068 struct usb_configuration *c)
3069 {
3070 struct ffs_function *func = ffs_func_from_usb(f);
3071 struct f_fs_opts *ffs_opts =
3072 container_of(f->fi, struct f_fs_opts, func_inst);
3073 struct ffs_data *ffs_data;
3074 int ret;
3075
3076 ENTER();
3077
3078 /*
3079 * Legacy gadget triggers binding in functionfs_ready_callback,
3080 * which already uses locking; taking the same lock here would
3081 * cause a deadlock.
3082 *
3083 * Configfs-enabled gadgets however do need ffs_dev_lock.
3084 */
3085 if (!ffs_opts->no_configfs)
3086 ffs_dev_lock();
3087 ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3088 ffs_data = ffs_opts->dev->ffs_data;
3089 if (!ffs_opts->no_configfs)
3090 ffs_dev_unlock();
3091 if (ret)
3092 return ERR_PTR(ret);
3093
3094 func->ffs = ffs_data;
3095 func->conf = c;
3096 func->gadget = c->cdev->gadget;
3097
3098 /*
3099 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3100 * configurations are bound in sequence with list_for_each_entry,
3101 * in each configuration its functions are bound in sequence
3102 * with list_for_each_entry, so we assume no race condition
3103 * with regard to ffs_opts->bound access
3104 */
3105 if (!ffs_opts->refcnt) {
3106 ret = functionfs_bind(func->ffs, c->cdev);
3107 if (ret)
3108 return ERR_PTR(ret);
3109 }
3110 ffs_opts->refcnt++;
3111 func->function.strings = func->ffs->stringtabs;
3112
3113 return ffs_opts;
3114 }
3115
_ffs_func_bind(struct usb_configuration * c,struct usb_function * f)3116 static int _ffs_func_bind(struct usb_configuration *c,
3117 struct usb_function *f)
3118 {
3119 struct ffs_function *func = ffs_func_from_usb(f);
3120 struct ffs_data *ffs = func->ffs;
3121
3122 const int full = !!func->ffs->fs_descs_count;
3123 const int high = !!func->ffs->hs_descs_count;
3124 const int super = !!func->ffs->ss_descs_count;
3125
3126 int fs_len, hs_len, ss_len, ret, i;
3127 struct ffs_ep *eps_ptr;
3128
3129 /* Make it a single chunk, less management later on */
3130 vla_group(d);
3131 vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3132 vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3133 full ? ffs->fs_descs_count + 1 : 0);
3134 vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3135 high ? ffs->hs_descs_count + 1 : 0);
3136 vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3137 super ? ffs->ss_descs_count + 1 : 0);
3138 vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3139 vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3140 c->cdev->use_os_string ? ffs->interfaces_count : 0);
3141 vla_item_with_sz(d, char[16], ext_compat,
3142 c->cdev->use_os_string ? ffs->interfaces_count : 0);
3143 vla_item_with_sz(d, struct usb_os_desc, os_desc,
3144 c->cdev->use_os_string ? ffs->interfaces_count : 0);
3145 vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3146 ffs->ms_os_descs_ext_prop_count);
3147 vla_item_with_sz(d, char, ext_prop_name,
3148 ffs->ms_os_descs_ext_prop_name_len);
3149 vla_item_with_sz(d, char, ext_prop_data,
3150 ffs->ms_os_descs_ext_prop_data_len);
3151 vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3152 char *vlabuf;
3153
3154 ENTER();
3155
3156 /* Has descriptors only for speeds gadget does not support */
3157 if (!(full | high | super))
3158 return -ENOTSUPP;
3159
3160 /* Allocate a single chunk, less management later on */
3161 vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3162 if (!vlabuf)
3163 return -ENOMEM;
3164
3165 ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3166 ffs->ms_os_descs_ext_prop_name_avail =
3167 vla_ptr(vlabuf, d, ext_prop_name);
3168 ffs->ms_os_descs_ext_prop_data_avail =
3169 vla_ptr(vlabuf, d, ext_prop_data);
3170
3171 /* Copy descriptors */
3172 memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3173 ffs->raw_descs_length);
3174
3175 memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3176 eps_ptr = vla_ptr(vlabuf, d, eps);
3177 for (i = 0; i < ffs->eps_count; i++)
3178 eps_ptr[i].num = -1;
3179
3180 /* Save pointers
3181 * d_eps == vlabuf, func->eps used to kfree vlabuf later
3182 */
3183 func->eps = vla_ptr(vlabuf, d, eps);
3184 func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3185
3186 /*
3187 * Go through all the endpoint descriptors and allocate
3188 * endpoints first, so that later we can rewrite the endpoint
3189 * numbers without worrying that it may be described later on.
3190 */
3191 if (full) {
3192 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3193 fs_len = ffs_do_descs(ffs->fs_descs_count,
3194 vla_ptr(vlabuf, d, raw_descs),
3195 d_raw_descs__sz,
3196 __ffs_func_bind_do_descs, func);
3197 if (fs_len < 0) {
3198 ret = fs_len;
3199 goto error;
3200 }
3201 } else {
3202 fs_len = 0;
3203 }
3204
3205 if (high) {
3206 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3207 hs_len = ffs_do_descs(ffs->hs_descs_count,
3208 vla_ptr(vlabuf, d, raw_descs) + fs_len,
3209 d_raw_descs__sz - fs_len,
3210 __ffs_func_bind_do_descs, func);
3211 if (hs_len < 0) {
3212 ret = hs_len;
3213 goto error;
3214 }
3215 } else {
3216 hs_len = 0;
3217 }
3218
3219 if (super) {
3220 func->function.ss_descriptors = func->function.ssp_descriptors =
3221 vla_ptr(vlabuf, d, ss_descs);
3222 ss_len = ffs_do_descs(ffs->ss_descs_count,
3223 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3224 d_raw_descs__sz - fs_len - hs_len,
3225 __ffs_func_bind_do_descs, func);
3226 if (ss_len < 0) {
3227 ret = ss_len;
3228 goto error;
3229 }
3230 } else {
3231 ss_len = 0;
3232 }
3233
3234 /*
3235 * Now handle interface numbers allocation and interface and
3236 * endpoint numbers rewriting. We can do that in one go
3237 * now.
3238 */
3239 ret = ffs_do_descs(ffs->fs_descs_count +
3240 (high ? ffs->hs_descs_count : 0) +
3241 (super ? ffs->ss_descs_count : 0),
3242 vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3243 __ffs_func_bind_do_nums, func);
3244 if (ret < 0)
3245 goto error;
3246
3247 func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3248 if (c->cdev->use_os_string) {
3249 for (i = 0; i < ffs->interfaces_count; ++i) {
3250 struct usb_os_desc *desc;
3251
3252 desc = func->function.os_desc_table[i].os_desc =
3253 vla_ptr(vlabuf, d, os_desc) +
3254 i * sizeof(struct usb_os_desc);
3255 desc->ext_compat_id =
3256 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3257 INIT_LIST_HEAD(&desc->ext_prop);
3258 }
3259 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3260 vla_ptr(vlabuf, d, raw_descs) +
3261 fs_len + hs_len + ss_len,
3262 d_raw_descs__sz - fs_len - hs_len -
3263 ss_len,
3264 __ffs_func_bind_do_os_desc, func);
3265 if (ret < 0)
3266 goto error;
3267 }
3268 func->function.os_desc_n =
3269 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3270
3271 /* And we're done */
3272 ffs_event_add(ffs, FUNCTIONFS_BIND);
3273 return 0;
3274
3275 error:
3276 /* XXX Do we need to release all claimed endpoints here? */
3277 return ret;
3278 }
3279
ffs_func_bind(struct usb_configuration * c,struct usb_function * f)3280 static int ffs_func_bind(struct usb_configuration *c,
3281 struct usb_function *f)
3282 {
3283 struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3284 struct ffs_function *func = ffs_func_from_usb(f);
3285 int ret;
3286
3287 if (IS_ERR(ffs_opts))
3288 return PTR_ERR(ffs_opts);
3289
3290 ret = _ffs_func_bind(c, f);
3291 if (ret && !--ffs_opts->refcnt)
3292 functionfs_unbind(func->ffs);
3293
3294 return ret;
3295 }
3296
3297
3298 /* Other USB function hooks *************************************************/
3299
ffs_reset_work(struct work_struct * work)3300 static void ffs_reset_work(struct work_struct *work)
3301 {
3302 struct ffs_data *ffs = container_of(work,
3303 struct ffs_data, reset_work);
3304 ffs_data_reset(ffs);
3305 }
3306
ffs_func_set_alt(struct usb_function * f,unsigned interface,unsigned alt)3307 static int ffs_func_set_alt(struct usb_function *f,
3308 unsigned interface, unsigned alt)
3309 {
3310 struct ffs_function *func = ffs_func_from_usb(f);
3311 struct ffs_data *ffs = func->ffs;
3312 int ret = 0, intf;
3313
3314 if (alt != (unsigned)-1) {
3315 intf = ffs_func_revmap_intf(func, interface);
3316 if (intf < 0)
3317 return intf;
3318 }
3319
3320 if (ffs->func)
3321 ffs_func_eps_disable(ffs->func);
3322
3323 if (ffs->state == FFS_DEACTIVATED) {
3324 ffs->state = FFS_CLOSING;
3325 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3326 schedule_work(&ffs->reset_work);
3327 return -ENODEV;
3328 }
3329
3330 if (ffs->state != FFS_ACTIVE)
3331 return -ENODEV;
3332
3333 if (alt == (unsigned)-1) {
3334 ffs->func = NULL;
3335 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3336 return 0;
3337 }
3338
3339 ffs->func = func;
3340 ret = ffs_func_eps_enable(func);
3341 if (ret >= 0)
3342 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3343 return ret;
3344 }
3345
ffs_func_disable(struct usb_function * f)3346 static void ffs_func_disable(struct usb_function *f)
3347 {
3348 ffs_func_set_alt(f, 0, (unsigned)-1);
3349 }
3350
ffs_func_setup(struct usb_function * f,const struct usb_ctrlrequest * creq)3351 static int ffs_func_setup(struct usb_function *f,
3352 const struct usb_ctrlrequest *creq)
3353 {
3354 struct ffs_function *func = ffs_func_from_usb(f);
3355 struct ffs_data *ffs = func->ffs;
3356 unsigned long flags;
3357 int ret;
3358
3359 ENTER();
3360
3361 pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3362 pr_vdebug("creq->bRequest = %02x\n", creq->bRequest);
3363 pr_vdebug("creq->wValue = %04x\n", le16_to_cpu(creq->wValue));
3364 pr_vdebug("creq->wIndex = %04x\n", le16_to_cpu(creq->wIndex));
3365 pr_vdebug("creq->wLength = %04x\n", le16_to_cpu(creq->wLength));
3366
3367 /*
3368 * Most requests directed to interface go through here
3369 * (notable exceptions are set/get interface) so we need to
3370 * handle them. All other either handled by composite or
3371 * passed to usb_configuration->setup() (if one is set). No
3372 * matter, we will handle requests directed to endpoint here
3373 * as well (as it's straightforward). Other request recipient
3374 * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3375 * is being used.
3376 */
3377 if (ffs->state != FFS_ACTIVE)
3378 return -ENODEV;
3379
3380 switch (creq->bRequestType & USB_RECIP_MASK) {
3381 case USB_RECIP_INTERFACE:
3382 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3383 if (ret < 0)
3384 return ret;
3385 break;
3386
3387 case USB_RECIP_ENDPOINT:
3388 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3389 if (ret < 0)
3390 return ret;
3391 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3392 ret = func->ffs->eps_addrmap[ret];
3393 break;
3394
3395 default:
3396 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3397 ret = le16_to_cpu(creq->wIndex);
3398 else
3399 return -EOPNOTSUPP;
3400 }
3401
3402 spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3403 ffs->ev.setup = *creq;
3404 ffs->ev.setup.wIndex = cpu_to_le16(ret);
3405 __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3406 spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3407
3408 return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3409 }
3410
ffs_func_req_match(struct usb_function * f,const struct usb_ctrlrequest * creq,bool config0)3411 static bool ffs_func_req_match(struct usb_function *f,
3412 const struct usb_ctrlrequest *creq,
3413 bool config0)
3414 {
3415 struct ffs_function *func = ffs_func_from_usb(f);
3416
3417 if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3418 return false;
3419
3420 switch (creq->bRequestType & USB_RECIP_MASK) {
3421 case USB_RECIP_INTERFACE:
3422 return (ffs_func_revmap_intf(func,
3423 le16_to_cpu(creq->wIndex)) >= 0);
3424 case USB_RECIP_ENDPOINT:
3425 return (ffs_func_revmap_ep(func,
3426 le16_to_cpu(creq->wIndex)) >= 0);
3427 default:
3428 return (bool) (func->ffs->user_flags &
3429 FUNCTIONFS_ALL_CTRL_RECIP);
3430 }
3431 }
3432
ffs_func_suspend(struct usb_function * f)3433 static void ffs_func_suspend(struct usb_function *f)
3434 {
3435 ENTER();
3436 ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3437 }
3438
ffs_func_resume(struct usb_function * f)3439 static void ffs_func_resume(struct usb_function *f)
3440 {
3441 ENTER();
3442 ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3443 }
3444
3445
3446 /* Endpoint and interface numbers reverse mapping ***************************/
3447
ffs_func_revmap_ep(struct ffs_function * func,u8 num)3448 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3449 {
3450 num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3451 return num ? num : -EDOM;
3452 }
3453
ffs_func_revmap_intf(struct ffs_function * func,u8 intf)3454 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3455 {
3456 short *nums = func->interfaces_nums;
3457 unsigned count = func->ffs->interfaces_count;
3458
3459 for (; count; --count, ++nums) {
3460 if (*nums >= 0 && *nums == intf)
3461 return nums - func->interfaces_nums;
3462 }
3463
3464 return -EDOM;
3465 }
3466
3467
3468 /* Devices management *******************************************************/
3469
3470 static LIST_HEAD(ffs_devices);
3471
_ffs_do_find_dev(const char * name)3472 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3473 {
3474 struct ffs_dev *dev;
3475
3476 if (!name)
3477 return NULL;
3478
3479 list_for_each_entry(dev, &ffs_devices, entry) {
3480 if (strcmp(dev->name, name) == 0)
3481 return dev;
3482 }
3483
3484 return NULL;
3485 }
3486
3487 /*
3488 * ffs_lock must be taken by the caller of this function
3489 */
_ffs_get_single_dev(void)3490 static struct ffs_dev *_ffs_get_single_dev(void)
3491 {
3492 struct ffs_dev *dev;
3493
3494 if (list_is_singular(&ffs_devices)) {
3495 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3496 if (dev->single)
3497 return dev;
3498 }
3499
3500 return NULL;
3501 }
3502
3503 /*
3504 * ffs_lock must be taken by the caller of this function
3505 */
_ffs_find_dev(const char * name)3506 static struct ffs_dev *_ffs_find_dev(const char *name)
3507 {
3508 struct ffs_dev *dev;
3509
3510 dev = _ffs_get_single_dev();
3511 if (dev)
3512 return dev;
3513
3514 return _ffs_do_find_dev(name);
3515 }
3516
3517 /* Configfs support *********************************************************/
3518
to_ffs_opts(struct config_item * item)3519 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3520 {
3521 return container_of(to_config_group(item), struct f_fs_opts,
3522 func_inst.group);
3523 }
3524
ffs_attr_release(struct config_item * item)3525 static void ffs_attr_release(struct config_item *item)
3526 {
3527 struct f_fs_opts *opts = to_ffs_opts(item);
3528
3529 usb_put_function_instance(&opts->func_inst);
3530 }
3531
3532 static struct configfs_item_operations ffs_item_ops = {
3533 .release = ffs_attr_release,
3534 };
3535
3536 static const struct config_item_type ffs_func_type = {
3537 .ct_item_ops = &ffs_item_ops,
3538 .ct_owner = THIS_MODULE,
3539 };
3540
3541
3542 /* Function registration interface ******************************************/
3543
ffs_free_inst(struct usb_function_instance * f)3544 static void ffs_free_inst(struct usb_function_instance *f)
3545 {
3546 struct f_fs_opts *opts;
3547
3548 opts = to_f_fs_opts(f);
3549 ffs_release_dev(opts->dev);
3550 ffs_dev_lock();
3551 _ffs_free_dev(opts->dev);
3552 ffs_dev_unlock();
3553 kfree(opts);
3554 }
3555
ffs_set_inst_name(struct usb_function_instance * fi,const char * name)3556 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3557 {
3558 if (strlen(name) >= sizeof_field(struct ffs_dev, name))
3559 return -ENAMETOOLONG;
3560 return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3561 }
3562
ffs_alloc_inst(void)3563 static struct usb_function_instance *ffs_alloc_inst(void)
3564 {
3565 struct f_fs_opts *opts;
3566 struct ffs_dev *dev;
3567
3568 opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3569 if (!opts)
3570 return ERR_PTR(-ENOMEM);
3571
3572 opts->func_inst.set_inst_name = ffs_set_inst_name;
3573 opts->func_inst.free_func_inst = ffs_free_inst;
3574 ffs_dev_lock();
3575 dev = _ffs_alloc_dev();
3576 ffs_dev_unlock();
3577 if (IS_ERR(dev)) {
3578 kfree(opts);
3579 return ERR_CAST(dev);
3580 }
3581 opts->dev = dev;
3582 dev->opts = opts;
3583
3584 config_group_init_type_name(&opts->func_inst.group, "",
3585 &ffs_func_type);
3586 return &opts->func_inst;
3587 }
3588
ffs_free(struct usb_function * f)3589 static void ffs_free(struct usb_function *f)
3590 {
3591 kfree(ffs_func_from_usb(f));
3592 }
3593
ffs_func_unbind(struct usb_configuration * c,struct usb_function * f)3594 static void ffs_func_unbind(struct usb_configuration *c,
3595 struct usb_function *f)
3596 {
3597 struct ffs_function *func = ffs_func_from_usb(f);
3598 struct ffs_data *ffs = func->ffs;
3599 struct f_fs_opts *opts =
3600 container_of(f->fi, struct f_fs_opts, func_inst);
3601 struct ffs_ep *ep = func->eps;
3602 unsigned count = ffs->eps_count;
3603 unsigned long flags;
3604
3605 ENTER();
3606 if (ffs->func == func) {
3607 ffs_func_eps_disable(func);
3608 ffs->func = NULL;
3609 }
3610
3611 /* Drain any pending AIO completions */
3612 drain_workqueue(ffs->io_completion_wq);
3613
3614 if (!--opts->refcnt)
3615 functionfs_unbind(ffs);
3616
3617 /* cleanup after autoconfig */
3618 spin_lock_irqsave(&func->ffs->eps_lock, flags);
3619 while (count--) {
3620 if (ep->ep && ep->req)
3621 usb_ep_free_request(ep->ep, ep->req);
3622 ep->req = NULL;
3623 ++ep;
3624 }
3625 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3626 kfree(func->eps);
3627 func->eps = NULL;
3628 /*
3629 * eps, descriptors and interfaces_nums are allocated in the
3630 * same chunk so only one free is required.
3631 */
3632 func->function.fs_descriptors = NULL;
3633 func->function.hs_descriptors = NULL;
3634 func->function.ss_descriptors = NULL;
3635 func->function.ssp_descriptors = NULL;
3636 func->interfaces_nums = NULL;
3637
3638 ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3639 }
3640
ffs_alloc(struct usb_function_instance * fi)3641 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3642 {
3643 struct ffs_function *func;
3644
3645 ENTER();
3646
3647 func = kzalloc(sizeof(*func), GFP_KERNEL);
3648 if (!func)
3649 return ERR_PTR(-ENOMEM);
3650
3651 func->function.name = "Function FS Gadget";
3652
3653 func->function.bind = ffs_func_bind;
3654 func->function.unbind = ffs_func_unbind;
3655 func->function.set_alt = ffs_func_set_alt;
3656 func->function.disable = ffs_func_disable;
3657 func->function.setup = ffs_func_setup;
3658 func->function.req_match = ffs_func_req_match;
3659 func->function.suspend = ffs_func_suspend;
3660 func->function.resume = ffs_func_resume;
3661 func->function.free_func = ffs_free;
3662
3663 return &func->function;
3664 }
3665
3666 /*
3667 * ffs_lock must be taken by the caller of this function
3668 */
_ffs_alloc_dev(void)3669 static struct ffs_dev *_ffs_alloc_dev(void)
3670 {
3671 struct ffs_dev *dev;
3672 int ret;
3673
3674 if (_ffs_get_single_dev())
3675 return ERR_PTR(-EBUSY);
3676
3677 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3678 if (!dev)
3679 return ERR_PTR(-ENOMEM);
3680
3681 if (list_empty(&ffs_devices)) {
3682 ret = functionfs_init();
3683 if (ret) {
3684 kfree(dev);
3685 return ERR_PTR(ret);
3686 }
3687 }
3688
3689 list_add(&dev->entry, &ffs_devices);
3690
3691 return dev;
3692 }
3693
ffs_name_dev(struct ffs_dev * dev,const char * name)3694 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3695 {
3696 struct ffs_dev *existing;
3697 int ret = 0;
3698
3699 ffs_dev_lock();
3700
3701 existing = _ffs_do_find_dev(name);
3702 if (!existing)
3703 strscpy(dev->name, name, ARRAY_SIZE(dev->name));
3704 else if (existing != dev)
3705 ret = -EBUSY;
3706
3707 ffs_dev_unlock();
3708
3709 return ret;
3710 }
3711 EXPORT_SYMBOL_GPL(ffs_name_dev);
3712
ffs_single_dev(struct ffs_dev * dev)3713 int ffs_single_dev(struct ffs_dev *dev)
3714 {
3715 int ret;
3716
3717 ret = 0;
3718 ffs_dev_lock();
3719
3720 if (!list_is_singular(&ffs_devices))
3721 ret = -EBUSY;
3722 else
3723 dev->single = true;
3724
3725 ffs_dev_unlock();
3726 return ret;
3727 }
3728 EXPORT_SYMBOL_GPL(ffs_single_dev);
3729
3730 /*
3731 * ffs_lock must be taken by the caller of this function
3732 */
_ffs_free_dev(struct ffs_dev * dev)3733 static void _ffs_free_dev(struct ffs_dev *dev)
3734 {
3735 list_del(&dev->entry);
3736
3737 kfree(dev);
3738 if (list_empty(&ffs_devices))
3739 functionfs_cleanup();
3740 }
3741
ffs_acquire_dev(const char * dev_name,struct ffs_data * ffs_data)3742 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data)
3743 {
3744 int ret = 0;
3745 struct ffs_dev *ffs_dev;
3746
3747 ENTER();
3748 ffs_dev_lock();
3749
3750 ffs_dev = _ffs_find_dev(dev_name);
3751 if (!ffs_dev) {
3752 ret = -ENOENT;
3753 } else if (ffs_dev->mounted) {
3754 ret = -EBUSY;
3755 } else if (ffs_dev->ffs_acquire_dev_callback &&
3756 ffs_dev->ffs_acquire_dev_callback(ffs_dev)) {
3757 ret = -ENOENT;
3758 } else {
3759 ffs_dev->mounted = true;
3760 ffs_dev->ffs_data = ffs_data;
3761 ffs_data->private_data = ffs_dev;
3762 }
3763
3764 ffs_dev_unlock();
3765 return ret;
3766 }
3767
ffs_release_dev(struct ffs_dev * ffs_dev)3768 static void ffs_release_dev(struct ffs_dev *ffs_dev)
3769 {
3770 ENTER();
3771 ffs_dev_lock();
3772
3773 if (ffs_dev && ffs_dev->mounted) {
3774 ffs_dev->mounted = false;
3775 if (ffs_dev->ffs_data) {
3776 ffs_dev->ffs_data->private_data = NULL;
3777 ffs_dev->ffs_data = NULL;
3778 }
3779
3780 if (ffs_dev->ffs_release_dev_callback)
3781 ffs_dev->ffs_release_dev_callback(ffs_dev);
3782 }
3783
3784 ffs_dev_unlock();
3785 }
3786
ffs_ready(struct ffs_data * ffs)3787 static int ffs_ready(struct ffs_data *ffs)
3788 {
3789 struct ffs_dev *ffs_obj;
3790 int ret = 0;
3791
3792 ENTER();
3793 ffs_dev_lock();
3794
3795 ffs_obj = ffs->private_data;
3796 if (!ffs_obj) {
3797 ret = -EINVAL;
3798 goto done;
3799 }
3800 if (WARN_ON(ffs_obj->desc_ready)) {
3801 ret = -EBUSY;
3802 goto done;
3803 }
3804
3805 ffs_obj->desc_ready = true;
3806
3807 if (ffs_obj->ffs_ready_callback) {
3808 ret = ffs_obj->ffs_ready_callback(ffs);
3809 if (ret)
3810 goto done;
3811 }
3812
3813 set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3814 done:
3815 ffs_dev_unlock();
3816 return ret;
3817 }
3818
ffs_closed(struct ffs_data * ffs)3819 static void ffs_closed(struct ffs_data *ffs)
3820 {
3821 struct ffs_dev *ffs_obj;
3822 struct f_fs_opts *opts;
3823 struct config_item *ci;
3824
3825 ENTER();
3826 ffs_dev_lock();
3827
3828 ffs_obj = ffs->private_data;
3829 if (!ffs_obj)
3830 goto done;
3831
3832 ffs_obj->desc_ready = false;
3833
3834 if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3835 ffs_obj->ffs_closed_callback)
3836 ffs_obj->ffs_closed_callback(ffs);
3837
3838 if (ffs_obj->opts)
3839 opts = ffs_obj->opts;
3840 else
3841 goto done;
3842
3843 if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3844 || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3845 goto done;
3846
3847 ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3848 ffs_dev_unlock();
3849
3850 if (test_bit(FFS_FL_BOUND, &ffs->flags))
3851 unregister_gadget_item(ci);
3852 return;
3853 done:
3854 ffs_dev_unlock();
3855 }
3856
3857 /* Misc helper functions ****************************************************/
3858
ffs_mutex_lock(struct mutex * mutex,unsigned nonblock)3859 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3860 {
3861 return nonblock
3862 ? mutex_trylock(mutex) ? 0 : -EAGAIN
3863 : mutex_lock_interruptible(mutex);
3864 }
3865
ffs_prepare_buffer(const char __user * buf,size_t len)3866 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3867 {
3868 char *data;
3869
3870 if (!len)
3871 return NULL;
3872
3873 data = memdup_user(buf, len);
3874 if (IS_ERR(data))
3875 return data;
3876
3877 pr_vdebug("Buffer from user space:\n");
3878 ffs_dump_mem("", data, len);
3879
3880 return data;
3881 }
3882
3883 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3884 MODULE_LICENSE("GPL");
3885 MODULE_AUTHOR("Michal Nazarewicz");
3886