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/dma-buf.h>
19 #include <linux/dma-fence.h>
20 #include <linux/dma-resv.h>
21 #include <linux/pagemap.h>
22 #include <linux/export.h>
23 #include <linux/fs_parser.h>
24 #include <linux/hid.h>
25 #include <linux/mm.h>
26 #include <linux/module.h>
27 #include <linux/scatterlist.h>
28 #include <linux/sched/signal.h>
29 #include <linux/uio.h>
30 #include <linux/vmalloc.h>
31 #include <asm/unaligned.h>
32
33 #include <linux/usb/ccid.h>
34 #include <linux/usb/composite.h>
35 #include <linux/usb/functionfs.h>
36
37 #include <linux/aio.h>
38 #include <linux/kthread.h>
39 #include <linux/poll.h>
40 #include <linux/eventfd.h>
41
42 #include "u_fs.h"
43 #include "u_f.h"
44 #include "u_os_desc.h"
45 #include "configfs.h"
46
47 #define FUNCTIONFS_MAGIC 0xa647361 /* Chosen by a honest dice roll ;) */
48 #define MAX_ALT_SETTINGS 2 /* Allow up to 2 alt settings to be set. */
49
50 #define DMABUF_ENQUEUE_TIMEOUT_MS 5000
51
52 MODULE_IMPORT_NS(DMA_BUF);
53
54 /* Reference counter handling */
55 static void ffs_data_get(struct ffs_data *ffs);
56 static void ffs_data_put(struct ffs_data *ffs);
57 /* Creates new ffs_data object. */
58 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
59 __attribute__((malloc));
60
61 /* Opened counter handling. */
62 static void ffs_data_opened(struct ffs_data *ffs);
63 static void ffs_data_closed(struct ffs_data *ffs);
64
65 /* Called with ffs->mutex held; take over ownership of data. */
66 static int __must_check
67 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
68 static int __must_check
69 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
70
71
72 /* The function structure ***************************************************/
73
74 struct ffs_ep;
75
76 struct ffs_function {
77 struct usb_configuration *conf;
78 struct usb_gadget *gadget;
79 struct ffs_data *ffs;
80
81 struct ffs_ep *eps;
82 u8 eps_revmap[16];
83 short *interfaces_nums;
84
85 struct usb_function function;
86 int cur_alt[MAX_CONFIG_INTERFACES];
87 };
88
89
ffs_func_from_usb(struct usb_function * f)90 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
91 {
92 return container_of(f, struct ffs_function, function);
93 }
94
95
96 static inline enum ffs_setup_state
ffs_setup_state_clear_cancelled(struct ffs_data * ffs)97 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
98 {
99 return (enum ffs_setup_state)
100 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
101 }
102
103
104 static void ffs_func_eps_disable(struct ffs_function *func);
105 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
106
107 static int ffs_func_bind(struct usb_configuration *,
108 struct usb_function *);
109 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
110 static int ffs_func_get_alt(struct usb_function *f, unsigned int intf);
111 static void ffs_func_disable(struct usb_function *);
112 static int ffs_func_setup(struct usb_function *,
113 const struct usb_ctrlrequest *);
114 static bool ffs_func_req_match(struct usb_function *,
115 const struct usb_ctrlrequest *,
116 bool config0);
117 static void ffs_func_suspend(struct usb_function *);
118 static void ffs_func_resume(struct usb_function *);
119
120
121 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
122 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
123
124
125 /* The endpoints structures *************************************************/
126
127 struct ffs_ep {
128 struct usb_ep *ep; /* P: ffs->eps_lock */
129 struct usb_request *req; /* P: epfile->mutex */
130
131 /* [0]: full speed, [1]: high speed, [2]: super speed */
132 struct usb_endpoint_descriptor *descs[3];
133
134 u8 num;
135 };
136
137 struct ffs_dmabuf_priv {
138 struct list_head entry;
139 struct kref ref;
140 struct ffs_data *ffs;
141 struct dma_buf_attachment *attach;
142 struct sg_table *sgt;
143 enum dma_data_direction dir;
144 spinlock_t lock;
145 u64 context;
146 struct usb_request *req; /* P: ffs->eps_lock */
147 struct usb_ep *ep; /* P: ffs->eps_lock */
148 };
149
150 struct ffs_dma_fence {
151 struct dma_fence base;
152 struct ffs_dmabuf_priv *priv;
153 struct work_struct work;
154 };
155
156 struct ffs_epfile {
157 /* Protects ep->ep and ep->req. */
158 struct mutex mutex;
159
160 struct ffs_data *ffs;
161 struct ffs_ep *ep; /* P: ffs->eps_lock */
162
163 struct dentry *dentry;
164
165 /*
166 * Buffer for holding data from partial reads which may happen since
167 * we’re rounding user read requests to a multiple of a max packet size.
168 *
169 * The pointer is initialised with NULL value and may be set by
170 * __ffs_epfile_read_data function to point to a temporary buffer.
171 *
172 * In normal operation, calls to __ffs_epfile_read_buffered will consume
173 * data from said buffer and eventually free it. Importantly, while the
174 * function is using the buffer, it sets the pointer to NULL. This is
175 * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
176 * can never run concurrently (they are synchronised by epfile->mutex)
177 * so the latter will not assign a new value to the pointer.
178 *
179 * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
180 * valid) and sets the pointer to READ_BUFFER_DROP value. This special
181 * value is crux of the synchronisation between ffs_func_eps_disable and
182 * __ffs_epfile_read_data.
183 *
184 * Once __ffs_epfile_read_data is about to finish it will try to set the
185 * pointer back to its old value (as described above), but seeing as the
186 * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
187 * the buffer.
188 *
189 * == State transitions ==
190 *
191 * • ptr == NULL: (initial state)
192 * ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
193 * ◦ __ffs_epfile_read_buffered: nop
194 * ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
195 * ◦ reading finishes: n/a, not in ‘and reading’ state
196 * • ptr == DROP:
197 * ◦ __ffs_epfile_read_buffer_free: nop
198 * ◦ __ffs_epfile_read_buffered: go to ptr == NULL
199 * ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
200 * ◦ reading finishes: n/a, not in ‘and reading’ state
201 * • ptr == buf:
202 * ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
203 * ◦ __ffs_epfile_read_buffered: go to ptr == NULL and reading
204 * ◦ __ffs_epfile_read_data: n/a, __ffs_epfile_read_buffered
205 * is always called first
206 * ◦ reading finishes: n/a, not in ‘and reading’ state
207 * • ptr == NULL and reading:
208 * ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
209 * ◦ __ffs_epfile_read_buffered: n/a, mutex is held
210 * ◦ __ffs_epfile_read_data: n/a, mutex is held
211 * ◦ reading finishes and …
212 * … all data read: free buf, go to ptr == NULL
213 * … otherwise: go to ptr == buf and reading
214 * • ptr == DROP and reading:
215 * ◦ __ffs_epfile_read_buffer_free: nop
216 * ◦ __ffs_epfile_read_buffered: n/a, mutex is held
217 * ◦ __ffs_epfile_read_data: n/a, mutex is held
218 * ◦ reading finishes: free buf, go to ptr == DROP
219 */
220 struct ffs_buffer *read_buffer;
221 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
222
223 char name[5];
224
225 unsigned char in; /* P: ffs->eps_lock */
226 unsigned char isoc; /* P: ffs->eps_lock */
227
228 unsigned char _pad;
229
230 /* Protects dmabufs */
231 struct mutex dmabufs_mutex;
232 struct list_head dmabufs; /* P: dmabufs_mutex */
233 atomic_t seqno;
234 };
235
236 struct ffs_buffer {
237 size_t length;
238 char *data;
239 char storage[] __counted_by(length);
240 };
241
242 /* ffs_io_data structure ***************************************************/
243
244 struct ffs_io_data {
245 bool aio;
246 bool read;
247
248 struct kiocb *kiocb;
249 struct iov_iter data;
250 const void *to_free;
251 char *buf;
252
253 struct mm_struct *mm;
254 struct work_struct work;
255
256 struct usb_ep *ep;
257 struct usb_request *req;
258 struct sg_table sgt;
259 bool use_sg;
260
261 struct ffs_data *ffs;
262
263 int status;
264 struct completion done;
265 };
266
267 struct ffs_desc_helper {
268 struct ffs_data *ffs;
269 unsigned interfaces_count;
270 unsigned eps_count;
271 };
272
273 static int __must_check ffs_epfiles_create(struct ffs_data *ffs);
274 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
275
276 static struct dentry *
277 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
278 const struct file_operations *fops);
279
280 /* Devices management *******************************************************/
281
282 DEFINE_MUTEX(ffs_lock);
283 EXPORT_SYMBOL_GPL(ffs_lock);
284
285 static struct ffs_dev *_ffs_find_dev(const char *name);
286 static struct ffs_dev *_ffs_alloc_dev(void);
287 static void _ffs_free_dev(struct ffs_dev *dev);
288 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data);
289 static void ffs_release_dev(struct ffs_dev *ffs_dev);
290 static int ffs_ready(struct ffs_data *ffs);
291 static void ffs_closed(struct ffs_data *ffs);
292
293 /* Misc helper functions ****************************************************/
294
295 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
296 __attribute__((warn_unused_result, nonnull));
297 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
298 __attribute__((warn_unused_result, nonnull));
299
300
301 /* Control file aka ep0 *****************************************************/
302
ffs_ep0_complete(struct usb_ep * ep,struct usb_request * req)303 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
304 {
305 struct ffs_data *ffs = req->context;
306
307 complete(&ffs->ep0req_completion);
308 }
309
__ffs_ep0_queue_wait(struct ffs_data * ffs,char * data,size_t len)310 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
311 __releases(&ffs->ev.waitq.lock)
312 {
313 struct usb_request *req = ffs->ep0req;
314 int ret;
315
316 if (!req) {
317 spin_unlock_irq(&ffs->ev.waitq.lock);
318 return -EINVAL;
319 }
320
321 req->zero = len < le16_to_cpu(ffs->ev.setup.wLength);
322
323 spin_unlock_irq(&ffs->ev.waitq.lock);
324
325 req->buf = data;
326 req->length = len;
327
328 /*
329 * UDC layer requires to provide a buffer even for ZLP, but should
330 * not use it at all. Let's provide some poisoned pointer to catch
331 * possible bug in the driver.
332 */
333 if (req->buf == NULL)
334 req->buf = (void *)0xDEADBABE;
335
336 reinit_completion(&ffs->ep0req_completion);
337
338 ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
339 if (ret < 0)
340 return ret;
341
342 ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
343 if (ret) {
344 usb_ep_dequeue(ffs->gadget->ep0, req);
345 return -EINTR;
346 }
347
348 ffs->setup_state = FFS_NO_SETUP;
349 return req->status ? req->status : req->actual;
350 }
351
__ffs_ep0_stall(struct ffs_data * ffs)352 static int __ffs_ep0_stall(struct ffs_data *ffs)
353 {
354 if (ffs->ev.can_stall) {
355 pr_vdebug("ep0 stall\n");
356 usb_ep_set_halt(ffs->gadget->ep0);
357 ffs->setup_state = FFS_NO_SETUP;
358 return -EL2HLT;
359 } else {
360 pr_debug("bogus ep0 stall!\n");
361 return -ESRCH;
362 }
363 }
364
ffs_ep0_write(struct file * file,const char __user * buf,size_t len,loff_t * ptr)365 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
366 size_t len, loff_t *ptr)
367 {
368 struct ffs_data *ffs = file->private_data;
369 ssize_t ret;
370 char *data;
371
372 /* Fast check if setup was canceled */
373 if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
374 return -EIDRM;
375
376 /* Acquire mutex */
377 ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
378 if (ret < 0)
379 return ret;
380
381 /* Check state */
382 switch (ffs->state) {
383 case FFS_READ_DESCRIPTORS:
384 case FFS_READ_STRINGS:
385 /* Copy data */
386 if (len < 16) {
387 ret = -EINVAL;
388 break;
389 }
390
391 data = ffs_prepare_buffer(buf, len);
392 if (IS_ERR(data)) {
393 ret = PTR_ERR(data);
394 break;
395 }
396
397 /* Handle data */
398 if (ffs->state == FFS_READ_DESCRIPTORS) {
399 pr_info("read descriptors\n");
400 ret = __ffs_data_got_descs(ffs, data, len);
401 if (ret < 0)
402 break;
403
404 ffs->state = FFS_READ_STRINGS;
405 ret = len;
406 } else {
407 pr_info("read strings\n");
408 ret = __ffs_data_got_strings(ffs, data, len);
409 if (ret < 0)
410 break;
411
412 ret = ffs_epfiles_create(ffs);
413 if (ret) {
414 ffs->state = FFS_CLOSING;
415 break;
416 }
417
418 ffs->state = FFS_ACTIVE;
419 mutex_unlock(&ffs->mutex);
420
421 ret = ffs_ready(ffs);
422 if (ret < 0) {
423 ffs->state = FFS_CLOSING;
424 return ret;
425 }
426
427 return len;
428 }
429 break;
430
431 case FFS_ACTIVE:
432 data = NULL;
433 /*
434 * We're called from user space, we can use _irq
435 * rather then _irqsave
436 */
437 spin_lock_irq(&ffs->ev.waitq.lock);
438 switch (ffs_setup_state_clear_cancelled(ffs)) {
439 case FFS_SETUP_CANCELLED:
440 ret = -EIDRM;
441 goto done_spin;
442
443 case FFS_NO_SETUP:
444 ret = -ESRCH;
445 goto done_spin;
446
447 case FFS_SETUP_PENDING:
448 break;
449 }
450
451 /* FFS_SETUP_PENDING */
452 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
453 spin_unlock_irq(&ffs->ev.waitq.lock);
454 ret = __ffs_ep0_stall(ffs);
455 break;
456 }
457
458 /* FFS_SETUP_PENDING and not stall */
459 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
460
461 spin_unlock_irq(&ffs->ev.waitq.lock);
462
463 data = ffs_prepare_buffer(buf, len);
464 if (IS_ERR(data)) {
465 ret = PTR_ERR(data);
466 break;
467 }
468
469 spin_lock_irq(&ffs->ev.waitq.lock);
470
471 /*
472 * We are guaranteed to be still in FFS_ACTIVE state
473 * but the state of setup could have changed from
474 * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
475 * to check for that. If that happened we copied data
476 * from user space in vain but it's unlikely.
477 *
478 * For sure we are not in FFS_NO_SETUP since this is
479 * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
480 * transition can be performed and it's protected by
481 * mutex.
482 */
483 if (ffs_setup_state_clear_cancelled(ffs) ==
484 FFS_SETUP_CANCELLED) {
485 ret = -EIDRM;
486 done_spin:
487 spin_unlock_irq(&ffs->ev.waitq.lock);
488 } else {
489 /* unlocks spinlock */
490 ret = __ffs_ep0_queue_wait(ffs, data, len);
491 }
492 kfree(data);
493 break;
494
495 default:
496 ret = -EBADFD;
497 break;
498 }
499
500 mutex_unlock(&ffs->mutex);
501 return ret;
502 }
503
504 /* 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)505 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
506 size_t n)
507 __releases(&ffs->ev.waitq.lock)
508 {
509 /*
510 * n cannot be bigger than ffs->ev.count, which cannot be bigger than
511 * size of ffs->ev.types array (which is four) so that's how much space
512 * we reserve.
513 */
514 struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
515 const size_t size = n * sizeof *events;
516 unsigned i = 0;
517
518 memset(events, 0, size);
519
520 do {
521 events[i].type = ffs->ev.types[i];
522 if (events[i].type == FUNCTIONFS_SETUP) {
523 events[i].u.setup = ffs->ev.setup;
524 ffs->setup_state = FFS_SETUP_PENDING;
525 }
526 } while (++i < n);
527
528 ffs->ev.count -= n;
529 if (ffs->ev.count)
530 memmove(ffs->ev.types, ffs->ev.types + n,
531 ffs->ev.count * sizeof *ffs->ev.types);
532
533 spin_unlock_irq(&ffs->ev.waitq.lock);
534 mutex_unlock(&ffs->mutex);
535
536 return copy_to_user(buf, events, size) ? -EFAULT : size;
537 }
538
ffs_ep0_read(struct file * file,char __user * buf,size_t len,loff_t * ptr)539 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
540 size_t len, loff_t *ptr)
541 {
542 struct ffs_data *ffs = file->private_data;
543 char *data = NULL;
544 size_t n;
545 int ret;
546
547 /* Fast check if setup was canceled */
548 if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
549 return -EIDRM;
550
551 /* Acquire mutex */
552 ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
553 if (ret < 0)
554 return ret;
555
556 /* Check state */
557 if (ffs->state != FFS_ACTIVE) {
558 ret = -EBADFD;
559 goto done_mutex;
560 }
561
562 /*
563 * We're called from user space, we can use _irq rather then
564 * _irqsave
565 */
566 spin_lock_irq(&ffs->ev.waitq.lock);
567
568 switch (ffs_setup_state_clear_cancelled(ffs)) {
569 case FFS_SETUP_CANCELLED:
570 ret = -EIDRM;
571 break;
572
573 case FFS_NO_SETUP:
574 n = len / sizeof(struct usb_functionfs_event);
575 if (!n) {
576 ret = -EINVAL;
577 break;
578 }
579
580 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
581 ret = -EAGAIN;
582 break;
583 }
584
585 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
586 ffs->ev.count)) {
587 ret = -EINTR;
588 break;
589 }
590
591 /* unlocks spinlock */
592 return __ffs_ep0_read_events(ffs, buf,
593 min(n, (size_t)ffs->ev.count));
594
595 case FFS_SETUP_PENDING:
596 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
597 spin_unlock_irq(&ffs->ev.waitq.lock);
598 ret = __ffs_ep0_stall(ffs);
599 goto done_mutex;
600 }
601
602 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
603
604 spin_unlock_irq(&ffs->ev.waitq.lock);
605
606 if (len) {
607 data = kmalloc(len, GFP_KERNEL);
608 if (!data) {
609 ret = -ENOMEM;
610 goto done_mutex;
611 }
612 }
613
614 spin_lock_irq(&ffs->ev.waitq.lock);
615
616 /* See ffs_ep0_write() */
617 if (ffs_setup_state_clear_cancelled(ffs) ==
618 FFS_SETUP_CANCELLED) {
619 ret = -EIDRM;
620 break;
621 }
622
623 /* unlocks spinlock */
624 ret = __ffs_ep0_queue_wait(ffs, data, len);
625 if ((ret > 0) && (copy_to_user(buf, data, len)))
626 ret = -EFAULT;
627 goto done_mutex;
628
629 default:
630 ret = -EBADFD;
631 break;
632 }
633
634 spin_unlock_irq(&ffs->ev.waitq.lock);
635 done_mutex:
636 mutex_unlock(&ffs->mutex);
637 kfree(data);
638 return ret;
639 }
640
ffs_ep0_open(struct inode * inode,struct file * file)641 static int ffs_ep0_open(struct inode *inode, struct file *file)
642 {
643 struct ffs_data *ffs = inode->i_private;
644
645 if (ffs->state == FFS_CLOSING)
646 return -EBUSY;
647
648 file->private_data = ffs;
649 ffs_data_opened(ffs);
650
651 return stream_open(inode, file);
652 }
653
ffs_ep0_release(struct inode * inode,struct file * file)654 static int ffs_ep0_release(struct inode *inode, struct file *file)
655 {
656 struct ffs_data *ffs = file->private_data;
657
658 ffs_data_closed(ffs);
659
660 return 0;
661 }
662
ffs_ep0_ioctl(struct file * file,unsigned code,unsigned long value)663 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
664 {
665 struct ffs_data *ffs = file->private_data;
666 struct usb_gadget *gadget = ffs->gadget;
667 long ret;
668
669 if (code == FUNCTIONFS_INTERFACE_REVMAP) {
670 struct ffs_function *func = ffs->func;
671 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
672 } else if (gadget && gadget->ops->ioctl) {
673 ret = gadget->ops->ioctl(gadget, code, value);
674 } else {
675 ret = -ENOTTY;
676 }
677
678 return ret;
679 }
680
ffs_ep0_poll(struct file * file,poll_table * wait)681 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
682 {
683 struct ffs_data *ffs = file->private_data;
684 __poll_t mask = EPOLLWRNORM;
685 int ret;
686
687 poll_wait(file, &ffs->ev.waitq, wait);
688
689 ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
690 if (ret < 0)
691 return mask;
692
693 switch (ffs->state) {
694 case FFS_READ_DESCRIPTORS:
695 case FFS_READ_STRINGS:
696 mask |= EPOLLOUT;
697 break;
698
699 case FFS_ACTIVE:
700 switch (ffs->setup_state) {
701 case FFS_NO_SETUP:
702 if (ffs->ev.count)
703 mask |= EPOLLIN;
704 break;
705
706 case FFS_SETUP_PENDING:
707 case FFS_SETUP_CANCELLED:
708 mask |= (EPOLLIN | EPOLLOUT);
709 break;
710 }
711 break;
712
713 case FFS_CLOSING:
714 break;
715 case FFS_DEACTIVATED:
716 break;
717 }
718
719 mutex_unlock(&ffs->mutex);
720
721 return mask;
722 }
723
724 static const struct file_operations ffs_ep0_operations = {
725 .llseek = no_llseek,
726
727 .open = ffs_ep0_open,
728 .write = ffs_ep0_write,
729 .read = ffs_ep0_read,
730 .release = ffs_ep0_release,
731 .unlocked_ioctl = ffs_ep0_ioctl,
732 .poll = ffs_ep0_poll,
733 };
734
735
736 /* "Normal" endpoints operations ********************************************/
737
ffs_epfile_io_complete(struct usb_ep * _ep,struct usb_request * req)738 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
739 {
740 struct ffs_io_data *io_data = req->context;
741
742 if (req->status)
743 io_data->status = req->status;
744 else
745 io_data->status = req->actual;
746
747 complete(&io_data->done);
748 }
749
ffs_copy_to_iter(void * data,int data_len,struct iov_iter * iter)750 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
751 {
752 ssize_t ret = copy_to_iter(data, data_len, iter);
753 if (ret == data_len)
754 return ret;
755
756 if (iov_iter_count(iter))
757 return -EFAULT;
758
759 /*
760 * Dear user space developer!
761 *
762 * TL;DR: To stop getting below error message in your kernel log, change
763 * user space code using functionfs to align read buffers to a max
764 * packet size.
765 *
766 * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
767 * packet size. When unaligned buffer is passed to functionfs, it
768 * internally uses a larger, aligned buffer so that such UDCs are happy.
769 *
770 * Unfortunately, this means that host may send more data than was
771 * requested in read(2) system call. f_fs doesn’t know what to do with
772 * that excess data so it simply drops it.
773 *
774 * Was the buffer aligned in the first place, no such problem would
775 * happen.
776 *
777 * Data may be dropped only in AIO reads. Synchronous reads are handled
778 * by splitting a request into multiple parts. This splitting may still
779 * be a problem though so it’s likely best to align the buffer
780 * regardless of it being AIO or not..
781 *
782 * This only affects OUT endpoints, i.e. reading data with a read(2),
783 * aio_read(2) etc. system calls. Writing data to an IN endpoint is not
784 * affected.
785 */
786 pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
787 "Align read buffer size to max packet size to avoid the problem.\n",
788 data_len, ret);
789
790 return ret;
791 }
792
793 /*
794 * allocate a virtually contiguous buffer and create a scatterlist describing it
795 * @sg_table - pointer to a place to be filled with sg_table contents
796 * @size - required buffer size
797 */
ffs_build_sg_list(struct sg_table * sgt,size_t sz)798 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
799 {
800 struct page **pages;
801 void *vaddr, *ptr;
802 unsigned int n_pages;
803 int i;
804
805 vaddr = vmalloc(sz);
806 if (!vaddr)
807 return NULL;
808
809 n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
810 pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
811 if (!pages) {
812 vfree(vaddr);
813
814 return NULL;
815 }
816 for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
817 pages[i] = vmalloc_to_page(ptr);
818
819 if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
820 kvfree(pages);
821 vfree(vaddr);
822
823 return NULL;
824 }
825 kvfree(pages);
826
827 return vaddr;
828 }
829
ffs_alloc_buffer(struct ffs_io_data * io_data,size_t data_len)830 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
831 size_t data_len)
832 {
833 if (io_data->use_sg)
834 return ffs_build_sg_list(&io_data->sgt, data_len);
835
836 return kmalloc(data_len, GFP_KERNEL);
837 }
838
ffs_free_buffer(struct ffs_io_data * io_data)839 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
840 {
841 if (!io_data->buf)
842 return;
843
844 if (io_data->use_sg) {
845 sg_free_table(&io_data->sgt);
846 vfree(io_data->buf);
847 } else {
848 kfree(io_data->buf);
849 }
850 }
851
ffs_user_copy_worker(struct work_struct * work)852 static void ffs_user_copy_worker(struct work_struct *work)
853 {
854 struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
855 work);
856 int ret = io_data->status;
857 bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
858 unsigned long flags;
859
860 if (io_data->read && ret > 0) {
861 kthread_use_mm(io_data->mm);
862 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
863 kthread_unuse_mm(io_data->mm);
864 }
865
866 io_data->kiocb->ki_complete(io_data->kiocb, ret);
867
868 if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
869 eventfd_signal(io_data->ffs->ffs_eventfd);
870
871 spin_lock_irqsave(&io_data->ffs->eps_lock, flags);
872 usb_ep_free_request(io_data->ep, io_data->req);
873 io_data->req = NULL;
874 spin_unlock_irqrestore(&io_data->ffs->eps_lock, flags);
875
876 if (io_data->read)
877 kfree(io_data->to_free);
878 ffs_free_buffer(io_data);
879 kfree(io_data);
880 }
881
ffs_epfile_async_io_complete(struct usb_ep * _ep,struct usb_request * req)882 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
883 struct usb_request *req)
884 {
885 struct ffs_io_data *io_data = req->context;
886 struct ffs_data *ffs = io_data->ffs;
887
888 io_data->status = req->status ? req->status : req->actual;
889
890 INIT_WORK(&io_data->work, ffs_user_copy_worker);
891 queue_work(ffs->io_completion_wq, &io_data->work);
892 }
893
__ffs_epfile_read_buffer_free(struct ffs_epfile * epfile)894 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
895 {
896 /*
897 * See comment in struct ffs_epfile for full read_buffer pointer
898 * synchronisation story.
899 */
900 struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
901 if (buf && buf != READ_BUFFER_DROP)
902 kfree(buf);
903 }
904
905 /* Assumes epfile->mutex is held. */
__ffs_epfile_read_buffered(struct ffs_epfile * epfile,struct iov_iter * iter)906 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
907 struct iov_iter *iter)
908 {
909 /*
910 * Null out epfile->read_buffer so ffs_func_eps_disable does not free
911 * the buffer while we are using it. See comment in struct ffs_epfile
912 * for full read_buffer pointer synchronisation story.
913 */
914 struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
915 ssize_t ret;
916 if (!buf || buf == READ_BUFFER_DROP)
917 return 0;
918
919 ret = copy_to_iter(buf->data, buf->length, iter);
920 if (buf->length == ret) {
921 kfree(buf);
922 return ret;
923 }
924
925 if (iov_iter_count(iter)) {
926 ret = -EFAULT;
927 } else {
928 buf->length -= ret;
929 buf->data += ret;
930 }
931
932 if (cmpxchg(&epfile->read_buffer, NULL, buf))
933 kfree(buf);
934
935 return ret;
936 }
937
938 /* Assumes epfile->mutex is held. */
__ffs_epfile_read_data(struct ffs_epfile * epfile,void * data,int data_len,struct iov_iter * iter)939 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
940 void *data, int data_len,
941 struct iov_iter *iter)
942 {
943 struct ffs_buffer *buf;
944
945 ssize_t ret = copy_to_iter(data, data_len, iter);
946 if (data_len == ret)
947 return ret;
948
949 if (iov_iter_count(iter))
950 return -EFAULT;
951
952 /* See ffs_copy_to_iter for more context. */
953 pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
954 data_len, ret);
955
956 data_len -= ret;
957 buf = kmalloc(struct_size(buf, storage, data_len), GFP_KERNEL);
958 if (!buf)
959 return -ENOMEM;
960 buf->length = data_len;
961 buf->data = buf->storage;
962 memcpy(buf->storage, data + ret, flex_array_size(buf, storage, data_len));
963
964 /*
965 * At this point read_buffer is NULL or READ_BUFFER_DROP (if
966 * ffs_func_eps_disable has been called in the meanwhile). See comment
967 * in struct ffs_epfile for full read_buffer pointer synchronisation
968 * story.
969 */
970 if (cmpxchg(&epfile->read_buffer, NULL, buf))
971 kfree(buf);
972
973 return ret;
974 }
975
ffs_epfile_wait_ep(struct file * file)976 static struct ffs_ep *ffs_epfile_wait_ep(struct file *file)
977 {
978 struct ffs_epfile *epfile = file->private_data;
979 struct ffs_ep *ep;
980 int ret;
981
982 /* Wait for endpoint to be enabled */
983 ep = epfile->ep;
984 if (!ep) {
985 if (file->f_flags & O_NONBLOCK)
986 return ERR_PTR(-EAGAIN);
987
988 ret = wait_event_interruptible(
989 epfile->ffs->wait, (ep = epfile->ep));
990 if (ret)
991 return ERR_PTR(-EINTR);
992 }
993
994 return ep;
995 }
996
ffs_epfile_io(struct file * file,struct ffs_io_data * io_data)997 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
998 {
999 struct ffs_epfile *epfile = file->private_data;
1000 struct usb_request *req;
1001 struct ffs_ep *ep;
1002 char *data = NULL;
1003 ssize_t ret, data_len = -EINVAL;
1004 int halt;
1005
1006 /* Are we still active? */
1007 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1008 return -ENODEV;
1009
1010 ep = ffs_epfile_wait_ep(file);
1011 if (IS_ERR(ep))
1012 return PTR_ERR(ep);
1013
1014 /* Do we halt? */
1015 halt = (!io_data->read == !epfile->in);
1016 if (halt && epfile->isoc)
1017 return -EINVAL;
1018
1019 /* We will be using request and read_buffer */
1020 ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
1021 if (ret)
1022 goto error;
1023
1024 /* Allocate & copy */
1025 if (!halt) {
1026 struct usb_gadget *gadget;
1027
1028 /*
1029 * Do we have buffered data from previous partial read? Check
1030 * that for synchronous case only because we do not have
1031 * facility to ‘wake up’ a pending asynchronous read and push
1032 * buffered data to it which we would need to make things behave
1033 * consistently.
1034 */
1035 if (!io_data->aio && io_data->read) {
1036 ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
1037 if (ret)
1038 goto error_mutex;
1039 }
1040
1041 /*
1042 * if we _do_ wait above, the epfile->ffs->gadget might be NULL
1043 * before the waiting completes, so do not assign to 'gadget'
1044 * earlier
1045 */
1046 gadget = epfile->ffs->gadget;
1047
1048 spin_lock_irq(&epfile->ffs->eps_lock);
1049 /* In the meantime, endpoint got disabled or changed. */
1050 if (epfile->ep != ep) {
1051 ret = -ESHUTDOWN;
1052 goto error_lock;
1053 }
1054 data_len = iov_iter_count(&io_data->data);
1055 /*
1056 * Controller may require buffer size to be aligned to
1057 * maxpacketsize of an out endpoint.
1058 */
1059 if (io_data->read)
1060 data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1061
1062 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1063 spin_unlock_irq(&epfile->ffs->eps_lock);
1064
1065 data = ffs_alloc_buffer(io_data, data_len);
1066 if (!data) {
1067 ret = -ENOMEM;
1068 goto error_mutex;
1069 }
1070 if (!io_data->read &&
1071 !copy_from_iter_full(data, data_len, &io_data->data)) {
1072 ret = -EFAULT;
1073 goto error_mutex;
1074 }
1075 }
1076
1077 spin_lock_irq(&epfile->ffs->eps_lock);
1078
1079 if (epfile->ep != ep) {
1080 /* In the meantime, endpoint got disabled or changed. */
1081 ret = -ESHUTDOWN;
1082 } else if (halt) {
1083 ret = usb_ep_set_halt(ep->ep);
1084 if (!ret)
1085 ret = -EBADMSG;
1086 } else if (data_len == -EINVAL) {
1087 /*
1088 * Sanity Check: even though data_len can't be used
1089 * uninitialized at the time I write this comment, some
1090 * compilers complain about this situation.
1091 * In order to keep the code clean from warnings, data_len is
1092 * being initialized to -EINVAL during its declaration, which
1093 * means we can't rely on compiler anymore to warn no future
1094 * changes won't result in data_len being used uninitialized.
1095 * For such reason, we're adding this redundant sanity check
1096 * here.
1097 */
1098 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1099 ret = -EINVAL;
1100 } else if (!io_data->aio) {
1101 bool interrupted = false;
1102
1103 req = ep->req;
1104 if (io_data->use_sg) {
1105 req->buf = NULL;
1106 req->sg = io_data->sgt.sgl;
1107 req->num_sgs = io_data->sgt.nents;
1108 } else {
1109 req->buf = data;
1110 req->num_sgs = 0;
1111 }
1112 req->length = data_len;
1113
1114 io_data->buf = data;
1115
1116 init_completion(&io_data->done);
1117 req->context = io_data;
1118 req->complete = ffs_epfile_io_complete;
1119
1120 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1121 if (ret < 0)
1122 goto error_lock;
1123
1124 spin_unlock_irq(&epfile->ffs->eps_lock);
1125
1126 if (wait_for_completion_interruptible(&io_data->done)) {
1127 spin_lock_irq(&epfile->ffs->eps_lock);
1128 if (epfile->ep != ep) {
1129 ret = -ESHUTDOWN;
1130 goto error_lock;
1131 }
1132 /*
1133 * To avoid race condition with ffs_epfile_io_complete,
1134 * dequeue the request first then check
1135 * status. usb_ep_dequeue API should guarantee no race
1136 * condition with req->complete callback.
1137 */
1138 usb_ep_dequeue(ep->ep, req);
1139 spin_unlock_irq(&epfile->ffs->eps_lock);
1140 wait_for_completion(&io_data->done);
1141 interrupted = io_data->status < 0;
1142 }
1143
1144 if (interrupted)
1145 ret = -EINTR;
1146 else if (io_data->read && io_data->status > 0)
1147 ret = __ffs_epfile_read_data(epfile, data, io_data->status,
1148 &io_data->data);
1149 else
1150 ret = io_data->status;
1151 goto error_mutex;
1152 } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1153 ret = -ENOMEM;
1154 } else {
1155 if (io_data->use_sg) {
1156 req->buf = NULL;
1157 req->sg = io_data->sgt.sgl;
1158 req->num_sgs = io_data->sgt.nents;
1159 } else {
1160 req->buf = data;
1161 req->num_sgs = 0;
1162 }
1163 req->length = data_len;
1164
1165 io_data->buf = data;
1166 io_data->ep = ep->ep;
1167 io_data->req = req;
1168 io_data->ffs = epfile->ffs;
1169
1170 req->context = io_data;
1171 req->complete = ffs_epfile_async_io_complete;
1172
1173 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1174 if (ret) {
1175 io_data->req = NULL;
1176 usb_ep_free_request(ep->ep, req);
1177 goto error_lock;
1178 }
1179
1180 ret = -EIOCBQUEUED;
1181 /*
1182 * Do not kfree the buffer in this function. It will be freed
1183 * by ffs_user_copy_worker.
1184 */
1185 data = NULL;
1186 }
1187
1188 error_lock:
1189 spin_unlock_irq(&epfile->ffs->eps_lock);
1190 error_mutex:
1191 mutex_unlock(&epfile->mutex);
1192 error:
1193 if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1194 ffs_free_buffer(io_data);
1195 return ret;
1196 }
1197
1198 static int
ffs_epfile_open(struct inode * inode,struct file * file)1199 ffs_epfile_open(struct inode *inode, struct file *file)
1200 {
1201 struct ffs_epfile *epfile = inode->i_private;
1202
1203 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1204 return -ENODEV;
1205
1206 file->private_data = epfile;
1207 ffs_data_opened(epfile->ffs);
1208
1209 return stream_open(inode, file);
1210 }
1211
ffs_aio_cancel(struct kiocb * kiocb)1212 static int ffs_aio_cancel(struct kiocb *kiocb)
1213 {
1214 struct ffs_io_data *io_data = kiocb->private;
1215 struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1216 unsigned long flags;
1217 int value;
1218
1219 spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1220
1221 if (io_data && io_data->ep && io_data->req)
1222 value = usb_ep_dequeue(io_data->ep, io_data->req);
1223 else
1224 value = -EINVAL;
1225
1226 spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1227
1228 return value;
1229 }
1230
ffs_epfile_write_iter(struct kiocb * kiocb,struct iov_iter * from)1231 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1232 {
1233 struct ffs_io_data io_data, *p = &io_data;
1234 ssize_t res;
1235
1236 if (!is_sync_kiocb(kiocb)) {
1237 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1238 if (!p)
1239 return -ENOMEM;
1240 p->aio = true;
1241 } else {
1242 memset(p, 0, sizeof(*p));
1243 p->aio = false;
1244 }
1245
1246 p->read = false;
1247 p->kiocb = kiocb;
1248 p->data = *from;
1249 p->mm = current->mm;
1250
1251 kiocb->private = p;
1252
1253 if (p->aio)
1254 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1255
1256 res = ffs_epfile_io(kiocb->ki_filp, p);
1257 if (res == -EIOCBQUEUED)
1258 return res;
1259 if (p->aio)
1260 kfree(p);
1261 else
1262 *from = p->data;
1263 return res;
1264 }
1265
ffs_epfile_read_iter(struct kiocb * kiocb,struct iov_iter * to)1266 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1267 {
1268 struct ffs_io_data io_data, *p = &io_data;
1269 ssize_t res;
1270
1271 if (!is_sync_kiocb(kiocb)) {
1272 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1273 if (!p)
1274 return -ENOMEM;
1275 p->aio = true;
1276 } else {
1277 memset(p, 0, sizeof(*p));
1278 p->aio = false;
1279 }
1280
1281 p->read = true;
1282 p->kiocb = kiocb;
1283 if (p->aio) {
1284 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1285 if (!iter_is_ubuf(&p->data) && !p->to_free) {
1286 kfree(p);
1287 return -ENOMEM;
1288 }
1289 } else {
1290 p->data = *to;
1291 p->to_free = NULL;
1292 }
1293 p->mm = current->mm;
1294
1295 kiocb->private = p;
1296
1297 if (p->aio)
1298 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1299
1300 res = ffs_epfile_io(kiocb->ki_filp, p);
1301 if (res == -EIOCBQUEUED)
1302 return res;
1303
1304 if (p->aio) {
1305 kfree(p->to_free);
1306 kfree(p);
1307 } else {
1308 *to = p->data;
1309 }
1310 return res;
1311 }
1312
ffs_dmabuf_release(struct kref * ref)1313 static void ffs_dmabuf_release(struct kref *ref)
1314 {
1315 struct ffs_dmabuf_priv *priv = container_of(ref, struct ffs_dmabuf_priv, ref);
1316 struct dma_buf_attachment *attach = priv->attach;
1317 struct dma_buf *dmabuf = attach->dmabuf;
1318
1319 pr_vdebug("FFS DMABUF release\n");
1320 dma_resv_lock(dmabuf->resv, NULL);
1321 dma_buf_unmap_attachment(attach, priv->sgt, priv->dir);
1322 dma_resv_unlock(dmabuf->resv);
1323
1324 dma_buf_detach(attach->dmabuf, attach);
1325 dma_buf_put(dmabuf);
1326 kfree(priv);
1327 }
1328
ffs_dmabuf_get(struct dma_buf_attachment * attach)1329 static void ffs_dmabuf_get(struct dma_buf_attachment *attach)
1330 {
1331 struct ffs_dmabuf_priv *priv = attach->importer_priv;
1332
1333 kref_get(&priv->ref);
1334 }
1335
ffs_dmabuf_put(struct dma_buf_attachment * attach)1336 static void ffs_dmabuf_put(struct dma_buf_attachment *attach)
1337 {
1338 struct ffs_dmabuf_priv *priv = attach->importer_priv;
1339
1340 kref_put(&priv->ref, ffs_dmabuf_release);
1341 }
1342
1343 static int
ffs_epfile_release(struct inode * inode,struct file * file)1344 ffs_epfile_release(struct inode *inode, struct file *file)
1345 {
1346 struct ffs_epfile *epfile = inode->i_private;
1347 struct ffs_dmabuf_priv *priv, *tmp;
1348 struct ffs_data *ffs = epfile->ffs;
1349
1350 mutex_lock(&epfile->dmabufs_mutex);
1351
1352 /* Close all attached DMABUFs */
1353 list_for_each_entry_safe(priv, tmp, &epfile->dmabufs, entry) {
1354 /* Cancel any pending transfer */
1355 spin_lock_irq(&ffs->eps_lock);
1356 if (priv->ep && priv->req)
1357 usb_ep_dequeue(priv->ep, priv->req);
1358 spin_unlock_irq(&ffs->eps_lock);
1359
1360 list_del(&priv->entry);
1361 ffs_dmabuf_put(priv->attach);
1362 }
1363
1364 mutex_unlock(&epfile->dmabufs_mutex);
1365
1366 __ffs_epfile_read_buffer_free(epfile);
1367 ffs_data_closed(epfile->ffs);
1368
1369 return 0;
1370 }
1371
ffs_dmabuf_cleanup(struct work_struct * work)1372 static void ffs_dmabuf_cleanup(struct work_struct *work)
1373 {
1374 struct ffs_dma_fence *dma_fence =
1375 container_of(work, struct ffs_dma_fence, work);
1376 struct ffs_dmabuf_priv *priv = dma_fence->priv;
1377 struct dma_buf_attachment *attach = priv->attach;
1378 struct dma_fence *fence = &dma_fence->base;
1379
1380 ffs_dmabuf_put(attach);
1381 dma_fence_put(fence);
1382 }
1383
ffs_dmabuf_signal_done(struct ffs_dma_fence * dma_fence,int ret)1384 static void ffs_dmabuf_signal_done(struct ffs_dma_fence *dma_fence, int ret)
1385 {
1386 struct ffs_dmabuf_priv *priv = dma_fence->priv;
1387 struct dma_fence *fence = &dma_fence->base;
1388 bool cookie = dma_fence_begin_signalling();
1389
1390 dma_fence_get(fence);
1391 fence->error = ret;
1392 dma_fence_signal(fence);
1393 dma_fence_end_signalling(cookie);
1394
1395 /*
1396 * The fence will be unref'd in ffs_dmabuf_cleanup.
1397 * It can't be done here, as the unref functions might try to lock
1398 * the resv object, which would deadlock.
1399 */
1400 INIT_WORK(&dma_fence->work, ffs_dmabuf_cleanup);
1401 queue_work(priv->ffs->io_completion_wq, &dma_fence->work);
1402 }
1403
ffs_epfile_dmabuf_io_complete(struct usb_ep * ep,struct usb_request * req)1404 static void ffs_epfile_dmabuf_io_complete(struct usb_ep *ep,
1405 struct usb_request *req)
1406 {
1407 pr_vdebug("FFS: DMABUF transfer complete, status=%d\n", req->status);
1408 ffs_dmabuf_signal_done(req->context, req->status);
1409 usb_ep_free_request(ep, req);
1410 }
1411
ffs_dmabuf_get_driver_name(struct dma_fence * fence)1412 static const char *ffs_dmabuf_get_driver_name(struct dma_fence *fence)
1413 {
1414 return "functionfs";
1415 }
1416
ffs_dmabuf_get_timeline_name(struct dma_fence * fence)1417 static const char *ffs_dmabuf_get_timeline_name(struct dma_fence *fence)
1418 {
1419 return "";
1420 }
1421
ffs_dmabuf_fence_release(struct dma_fence * fence)1422 static void ffs_dmabuf_fence_release(struct dma_fence *fence)
1423 {
1424 struct ffs_dma_fence *dma_fence =
1425 container_of(fence, struct ffs_dma_fence, base);
1426
1427 kfree(dma_fence);
1428 }
1429
1430 static const struct dma_fence_ops ffs_dmabuf_fence_ops = {
1431 .get_driver_name = ffs_dmabuf_get_driver_name,
1432 .get_timeline_name = ffs_dmabuf_get_timeline_name,
1433 .release = ffs_dmabuf_fence_release,
1434 };
1435
ffs_dma_resv_lock(struct dma_buf * dmabuf,bool nonblock)1436 static int ffs_dma_resv_lock(struct dma_buf *dmabuf, bool nonblock)
1437 {
1438 if (!nonblock)
1439 return dma_resv_lock_interruptible(dmabuf->resv, NULL);
1440
1441 if (!dma_resv_trylock(dmabuf->resv))
1442 return -EBUSY;
1443
1444 return 0;
1445 }
1446
1447 static struct dma_buf_attachment *
ffs_dmabuf_find_attachment(struct ffs_epfile * epfile,struct dma_buf * dmabuf)1448 ffs_dmabuf_find_attachment(struct ffs_epfile *epfile, struct dma_buf *dmabuf)
1449 {
1450 struct device *dev = epfile->ffs->gadget->dev.parent;
1451 struct dma_buf_attachment *attach = NULL;
1452 struct ffs_dmabuf_priv *priv;
1453
1454 mutex_lock(&epfile->dmabufs_mutex);
1455
1456 list_for_each_entry(priv, &epfile->dmabufs, entry) {
1457 if (priv->attach->dev == dev
1458 && priv->attach->dmabuf == dmabuf) {
1459 attach = priv->attach;
1460 break;
1461 }
1462 }
1463
1464 if (attach)
1465 ffs_dmabuf_get(attach);
1466
1467 mutex_unlock(&epfile->dmabufs_mutex);
1468
1469 return attach ?: ERR_PTR(-EPERM);
1470 }
1471
ffs_dmabuf_attach(struct file * file,int fd)1472 static int ffs_dmabuf_attach(struct file *file, int fd)
1473 {
1474 bool nonblock = file->f_flags & O_NONBLOCK;
1475 struct ffs_epfile *epfile = file->private_data;
1476 struct usb_gadget *gadget = epfile->ffs->gadget;
1477 struct dma_buf_attachment *attach;
1478 struct ffs_dmabuf_priv *priv;
1479 enum dma_data_direction dir;
1480 struct sg_table *sg_table;
1481 struct dma_buf *dmabuf;
1482 int err;
1483
1484 if (!gadget || !gadget->sg_supported)
1485 return -EPERM;
1486
1487 dmabuf = dma_buf_get(fd);
1488 if (IS_ERR(dmabuf))
1489 return PTR_ERR(dmabuf);
1490
1491 attach = dma_buf_attach(dmabuf, gadget->dev.parent);
1492 if (IS_ERR(attach)) {
1493 err = PTR_ERR(attach);
1494 goto err_dmabuf_put;
1495 }
1496
1497 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1498 if (!priv) {
1499 err = -ENOMEM;
1500 goto err_dmabuf_detach;
1501 }
1502
1503 dir = epfile->in ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
1504
1505 err = ffs_dma_resv_lock(dmabuf, nonblock);
1506 if (err)
1507 goto err_free_priv;
1508
1509 sg_table = dma_buf_map_attachment(attach, dir);
1510 dma_resv_unlock(dmabuf->resv);
1511
1512 if (IS_ERR(sg_table)) {
1513 err = PTR_ERR(sg_table);
1514 goto err_free_priv;
1515 }
1516
1517 attach->importer_priv = priv;
1518
1519 priv->sgt = sg_table;
1520 priv->dir = dir;
1521 priv->ffs = epfile->ffs;
1522 priv->attach = attach;
1523 spin_lock_init(&priv->lock);
1524 kref_init(&priv->ref);
1525 priv->context = dma_fence_context_alloc(1);
1526
1527 mutex_lock(&epfile->dmabufs_mutex);
1528 list_add(&priv->entry, &epfile->dmabufs);
1529 mutex_unlock(&epfile->dmabufs_mutex);
1530
1531 return 0;
1532
1533 err_free_priv:
1534 kfree(priv);
1535 err_dmabuf_detach:
1536 dma_buf_detach(dmabuf, attach);
1537 err_dmabuf_put:
1538 dma_buf_put(dmabuf);
1539
1540 return err;
1541 }
1542
ffs_dmabuf_detach(struct file * file,int fd)1543 static int ffs_dmabuf_detach(struct file *file, int fd)
1544 {
1545 struct ffs_epfile *epfile = file->private_data;
1546 struct ffs_data *ffs = epfile->ffs;
1547 struct device *dev = ffs->gadget->dev.parent;
1548 struct ffs_dmabuf_priv *priv, *tmp;
1549 struct dma_buf *dmabuf;
1550 int ret = -EPERM;
1551
1552 dmabuf = dma_buf_get(fd);
1553 if (IS_ERR(dmabuf))
1554 return PTR_ERR(dmabuf);
1555
1556 mutex_lock(&epfile->dmabufs_mutex);
1557
1558 list_for_each_entry_safe(priv, tmp, &epfile->dmabufs, entry) {
1559 if (priv->attach->dev == dev
1560 && priv->attach->dmabuf == dmabuf) {
1561 /* Cancel any pending transfer */
1562 spin_lock_irq(&ffs->eps_lock);
1563 if (priv->ep && priv->req)
1564 usb_ep_dequeue(priv->ep, priv->req);
1565 spin_unlock_irq(&ffs->eps_lock);
1566
1567 list_del(&priv->entry);
1568
1569 /* Unref the reference from ffs_dmabuf_attach() */
1570 ffs_dmabuf_put(priv->attach);
1571 ret = 0;
1572 break;
1573 }
1574 }
1575
1576 mutex_unlock(&epfile->dmabufs_mutex);
1577 dma_buf_put(dmabuf);
1578
1579 return ret;
1580 }
1581
ffs_dmabuf_transfer(struct file * file,const struct usb_ffs_dmabuf_transfer_req * req)1582 static int ffs_dmabuf_transfer(struct file *file,
1583 const struct usb_ffs_dmabuf_transfer_req *req)
1584 {
1585 bool nonblock = file->f_flags & O_NONBLOCK;
1586 struct ffs_epfile *epfile = file->private_data;
1587 struct dma_buf_attachment *attach;
1588 struct ffs_dmabuf_priv *priv;
1589 struct ffs_dma_fence *fence;
1590 struct usb_request *usb_req;
1591 enum dma_resv_usage resv_dir;
1592 struct dma_buf *dmabuf;
1593 unsigned long timeout;
1594 struct ffs_ep *ep;
1595 bool cookie;
1596 u32 seqno;
1597 long retl;
1598 int ret;
1599
1600 if (req->flags & ~USB_FFS_DMABUF_TRANSFER_MASK)
1601 return -EINVAL;
1602
1603 dmabuf = dma_buf_get(req->fd);
1604 if (IS_ERR(dmabuf))
1605 return PTR_ERR(dmabuf);
1606
1607 if (req->length > dmabuf->size || req->length == 0) {
1608 ret = -EINVAL;
1609 goto err_dmabuf_put;
1610 }
1611
1612 attach = ffs_dmabuf_find_attachment(epfile, dmabuf);
1613 if (IS_ERR(attach)) {
1614 ret = PTR_ERR(attach);
1615 goto err_dmabuf_put;
1616 }
1617
1618 priv = attach->importer_priv;
1619
1620 ep = ffs_epfile_wait_ep(file);
1621 if (IS_ERR(ep)) {
1622 ret = PTR_ERR(ep);
1623 goto err_attachment_put;
1624 }
1625
1626 ret = ffs_dma_resv_lock(dmabuf, nonblock);
1627 if (ret)
1628 goto err_attachment_put;
1629
1630 /* Make sure we don't have writers */
1631 timeout = nonblock ? 0 : msecs_to_jiffies(DMABUF_ENQUEUE_TIMEOUT_MS);
1632 retl = dma_resv_wait_timeout(dmabuf->resv,
1633 dma_resv_usage_rw(epfile->in),
1634 true, timeout);
1635 if (retl == 0)
1636 retl = -EBUSY;
1637 if (retl < 0) {
1638 ret = (int)retl;
1639 goto err_resv_unlock;
1640 }
1641
1642 ret = dma_resv_reserve_fences(dmabuf->resv, 1);
1643 if (ret)
1644 goto err_resv_unlock;
1645
1646 fence = kmalloc(sizeof(*fence), GFP_KERNEL);
1647 if (!fence) {
1648 ret = -ENOMEM;
1649 goto err_resv_unlock;
1650 }
1651
1652 fence->priv = priv;
1653
1654 spin_lock_irq(&epfile->ffs->eps_lock);
1655
1656 /* In the meantime, endpoint got disabled or changed. */
1657 if (epfile->ep != ep) {
1658 ret = -ESHUTDOWN;
1659 goto err_fence_put;
1660 }
1661
1662 usb_req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC);
1663 if (!usb_req) {
1664 ret = -ENOMEM;
1665 goto err_fence_put;
1666 }
1667
1668 /*
1669 * usb_ep_queue() guarantees that all transfers are processed in the
1670 * order they are enqueued, so we can use a simple incrementing
1671 * sequence number for the dma_fence.
1672 */
1673 seqno = atomic_add_return(1, &epfile->seqno);
1674
1675 dma_fence_init(&fence->base, &ffs_dmabuf_fence_ops,
1676 &priv->lock, priv->context, seqno);
1677
1678 resv_dir = epfile->in ? DMA_RESV_USAGE_WRITE : DMA_RESV_USAGE_READ;
1679
1680 dma_resv_add_fence(dmabuf->resv, &fence->base, resv_dir);
1681 dma_resv_unlock(dmabuf->resv);
1682
1683 /* Now that the dma_fence is in place, queue the transfer. */
1684
1685 usb_req->length = req->length;
1686 usb_req->buf = NULL;
1687 usb_req->sg = priv->sgt->sgl;
1688 usb_req->num_sgs = sg_nents_for_len(priv->sgt->sgl, req->length);
1689 usb_req->sg_was_mapped = true;
1690 usb_req->context = fence;
1691 usb_req->complete = ffs_epfile_dmabuf_io_complete;
1692
1693 cookie = dma_fence_begin_signalling();
1694 ret = usb_ep_queue(ep->ep, usb_req, GFP_ATOMIC);
1695 dma_fence_end_signalling(cookie);
1696 if (!ret) {
1697 priv->req = usb_req;
1698 priv->ep = ep->ep;
1699 } else {
1700 pr_warn("FFS: Failed to queue DMABUF: %d\n", ret);
1701 ffs_dmabuf_signal_done(fence, ret);
1702 usb_ep_free_request(ep->ep, usb_req);
1703 }
1704
1705 spin_unlock_irq(&epfile->ffs->eps_lock);
1706 dma_buf_put(dmabuf);
1707
1708 return ret;
1709
1710 err_fence_put:
1711 spin_unlock_irq(&epfile->ffs->eps_lock);
1712 dma_fence_put(&fence->base);
1713 err_resv_unlock:
1714 dma_resv_unlock(dmabuf->resv);
1715 err_attachment_put:
1716 ffs_dmabuf_put(attach);
1717 err_dmabuf_put:
1718 dma_buf_put(dmabuf);
1719
1720 return ret;
1721 }
1722
ffs_epfile_ioctl(struct file * file,unsigned code,unsigned long value)1723 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1724 unsigned long value)
1725 {
1726 struct ffs_epfile *epfile = file->private_data;
1727 struct ffs_ep *ep;
1728 int ret;
1729
1730 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1731 return -ENODEV;
1732
1733 switch (code) {
1734 case FUNCTIONFS_DMABUF_ATTACH:
1735 {
1736 int fd;
1737
1738 if (copy_from_user(&fd, (void __user *)value, sizeof(fd))) {
1739 ret = -EFAULT;
1740 break;
1741 }
1742
1743 return ffs_dmabuf_attach(file, fd);
1744 }
1745 case FUNCTIONFS_DMABUF_DETACH:
1746 {
1747 int fd;
1748
1749 if (copy_from_user(&fd, (void __user *)value, sizeof(fd))) {
1750 ret = -EFAULT;
1751 break;
1752 }
1753
1754 return ffs_dmabuf_detach(file, fd);
1755 }
1756 case FUNCTIONFS_DMABUF_TRANSFER:
1757 {
1758 struct usb_ffs_dmabuf_transfer_req req;
1759
1760 if (copy_from_user(&req, (void __user *)value, sizeof(req))) {
1761 ret = -EFAULT;
1762 break;
1763 }
1764
1765 return ffs_dmabuf_transfer(file, &req);
1766 }
1767 default:
1768 break;
1769 }
1770
1771 /* Wait for endpoint to be enabled */
1772 ep = ffs_epfile_wait_ep(file);
1773 if (IS_ERR(ep))
1774 return PTR_ERR(ep);
1775
1776 spin_lock_irq(&epfile->ffs->eps_lock);
1777
1778 /* In the meantime, endpoint got disabled or changed. */
1779 if (epfile->ep != ep) {
1780 spin_unlock_irq(&epfile->ffs->eps_lock);
1781 return -ESHUTDOWN;
1782 }
1783
1784 switch (code) {
1785 case FUNCTIONFS_FIFO_STATUS:
1786 ret = usb_ep_fifo_status(epfile->ep->ep);
1787 break;
1788 case FUNCTIONFS_FIFO_FLUSH:
1789 usb_ep_fifo_flush(epfile->ep->ep);
1790 ret = 0;
1791 break;
1792 case FUNCTIONFS_CLEAR_HALT:
1793 ret = usb_ep_clear_halt(epfile->ep->ep);
1794 break;
1795 case FUNCTIONFS_ENDPOINT_REVMAP:
1796 ret = epfile->ep->num;
1797 break;
1798 case FUNCTIONFS_ENDPOINT_DESC:
1799 {
1800 int desc_idx;
1801 struct usb_endpoint_descriptor desc1, *desc;
1802
1803 switch (epfile->ffs->gadget->speed) {
1804 case USB_SPEED_SUPER:
1805 case USB_SPEED_SUPER_PLUS:
1806 desc_idx = 2;
1807 break;
1808 case USB_SPEED_HIGH:
1809 desc_idx = 1;
1810 break;
1811 default:
1812 desc_idx = 0;
1813 }
1814
1815 desc = epfile->ep->descs[desc_idx];
1816 memcpy(&desc1, desc, desc->bLength);
1817
1818 spin_unlock_irq(&epfile->ffs->eps_lock);
1819 ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
1820 if (ret)
1821 ret = -EFAULT;
1822 return ret;
1823 }
1824 default:
1825 ret = -ENOTTY;
1826 }
1827 spin_unlock_irq(&epfile->ffs->eps_lock);
1828
1829 return ret;
1830 }
1831
1832 static const struct file_operations ffs_epfile_operations = {
1833 .llseek = no_llseek,
1834
1835 .open = ffs_epfile_open,
1836 .write_iter = ffs_epfile_write_iter,
1837 .read_iter = ffs_epfile_read_iter,
1838 .release = ffs_epfile_release,
1839 .unlocked_ioctl = ffs_epfile_ioctl,
1840 .compat_ioctl = compat_ptr_ioctl,
1841 };
1842
1843
1844 /* File system and super block operations ***********************************/
1845
1846 /*
1847 * Mounting the file system creates a controller file, used first for
1848 * function configuration then later for event monitoring.
1849 */
1850
1851 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)1852 ffs_sb_make_inode(struct super_block *sb, void *data,
1853 const struct file_operations *fops,
1854 const struct inode_operations *iops,
1855 struct ffs_file_perms *perms)
1856 {
1857 struct inode *inode;
1858
1859 inode = new_inode(sb);
1860
1861 if (inode) {
1862 struct timespec64 ts = inode_set_ctime_current(inode);
1863
1864 inode->i_ino = get_next_ino();
1865 inode->i_mode = perms->mode;
1866 inode->i_uid = perms->uid;
1867 inode->i_gid = perms->gid;
1868 inode_set_atime_to_ts(inode, ts);
1869 inode_set_mtime_to_ts(inode, ts);
1870 inode->i_private = data;
1871 if (fops)
1872 inode->i_fop = fops;
1873 if (iops)
1874 inode->i_op = iops;
1875 }
1876
1877 return inode;
1878 }
1879
1880 /* Create "regular" file */
ffs_sb_create_file(struct super_block * sb,const char * name,void * data,const struct file_operations * fops)1881 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1882 const char *name, void *data,
1883 const struct file_operations *fops)
1884 {
1885 struct ffs_data *ffs = sb->s_fs_info;
1886 struct dentry *dentry;
1887 struct inode *inode;
1888
1889 dentry = d_alloc_name(sb->s_root, name);
1890 if (!dentry)
1891 return NULL;
1892
1893 inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1894 if (!inode) {
1895 dput(dentry);
1896 return NULL;
1897 }
1898
1899 d_add(dentry, inode);
1900 return dentry;
1901 }
1902
1903 /* Super block */
1904 static const struct super_operations ffs_sb_operations = {
1905 .statfs = simple_statfs,
1906 .drop_inode = generic_delete_inode,
1907 };
1908
1909 struct ffs_sb_fill_data {
1910 struct ffs_file_perms perms;
1911 umode_t root_mode;
1912 const char *dev_name;
1913 bool no_disconnect;
1914 struct ffs_data *ffs_data;
1915 };
1916
ffs_sb_fill(struct super_block * sb,struct fs_context * fc)1917 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1918 {
1919 struct ffs_sb_fill_data *data = fc->fs_private;
1920 struct inode *inode;
1921 struct ffs_data *ffs = data->ffs_data;
1922
1923 ffs->sb = sb;
1924 data->ffs_data = NULL;
1925 sb->s_fs_info = ffs;
1926 sb->s_blocksize = PAGE_SIZE;
1927 sb->s_blocksize_bits = PAGE_SHIFT;
1928 sb->s_magic = FUNCTIONFS_MAGIC;
1929 sb->s_op = &ffs_sb_operations;
1930 sb->s_time_gran = 1;
1931
1932 /* Root inode */
1933 data->perms.mode = data->root_mode;
1934 inode = ffs_sb_make_inode(sb, NULL,
1935 &simple_dir_operations,
1936 &simple_dir_inode_operations,
1937 &data->perms);
1938 sb->s_root = d_make_root(inode);
1939 if (!sb->s_root)
1940 return -ENOMEM;
1941
1942 /* EP0 file */
1943 if (!ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations))
1944 return -ENOMEM;
1945
1946 return 0;
1947 }
1948
1949 enum {
1950 Opt_no_disconnect,
1951 Opt_rmode,
1952 Opt_fmode,
1953 Opt_mode,
1954 Opt_uid,
1955 Opt_gid,
1956 };
1957
1958 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1959 fsparam_bool ("no_disconnect", Opt_no_disconnect),
1960 fsparam_u32 ("rmode", Opt_rmode),
1961 fsparam_u32 ("fmode", Opt_fmode),
1962 fsparam_u32 ("mode", Opt_mode),
1963 fsparam_u32 ("uid", Opt_uid),
1964 fsparam_u32 ("gid", Opt_gid),
1965 {}
1966 };
1967
ffs_fs_parse_param(struct fs_context * fc,struct fs_parameter * param)1968 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1969 {
1970 struct ffs_sb_fill_data *data = fc->fs_private;
1971 struct fs_parse_result result;
1972 int opt;
1973
1974 opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1975 if (opt < 0)
1976 return opt;
1977
1978 switch (opt) {
1979 case Opt_no_disconnect:
1980 data->no_disconnect = result.boolean;
1981 break;
1982 case Opt_rmode:
1983 data->root_mode = (result.uint_32 & 0555) | S_IFDIR;
1984 break;
1985 case Opt_fmode:
1986 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1987 break;
1988 case Opt_mode:
1989 data->root_mode = (result.uint_32 & 0555) | S_IFDIR;
1990 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1991 break;
1992
1993 case Opt_uid:
1994 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1995 if (!uid_valid(data->perms.uid))
1996 goto unmapped_value;
1997 break;
1998 case Opt_gid:
1999 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
2000 if (!gid_valid(data->perms.gid))
2001 goto unmapped_value;
2002 break;
2003
2004 default:
2005 return -ENOPARAM;
2006 }
2007
2008 return 0;
2009
2010 unmapped_value:
2011 return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
2012 }
2013
2014 /*
2015 * Set up the superblock for a mount.
2016 */
ffs_fs_get_tree(struct fs_context * fc)2017 static int ffs_fs_get_tree(struct fs_context *fc)
2018 {
2019 struct ffs_sb_fill_data *ctx = fc->fs_private;
2020 struct ffs_data *ffs;
2021 int ret;
2022
2023 if (!fc->source)
2024 return invalf(fc, "No source specified");
2025
2026 ffs = ffs_data_new(fc->source);
2027 if (!ffs)
2028 return -ENOMEM;
2029 ffs->file_perms = ctx->perms;
2030 ffs->no_disconnect = ctx->no_disconnect;
2031
2032 ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
2033 if (!ffs->dev_name) {
2034 ffs_data_put(ffs);
2035 return -ENOMEM;
2036 }
2037
2038 ret = ffs_acquire_dev(ffs->dev_name, ffs);
2039 if (ret) {
2040 ffs_data_put(ffs);
2041 return ret;
2042 }
2043
2044 ctx->ffs_data = ffs;
2045 return get_tree_nodev(fc, ffs_sb_fill);
2046 }
2047
ffs_fs_free_fc(struct fs_context * fc)2048 static void ffs_fs_free_fc(struct fs_context *fc)
2049 {
2050 struct ffs_sb_fill_data *ctx = fc->fs_private;
2051
2052 if (ctx) {
2053 if (ctx->ffs_data) {
2054 ffs_data_put(ctx->ffs_data);
2055 }
2056
2057 kfree(ctx);
2058 }
2059 }
2060
2061 static const struct fs_context_operations ffs_fs_context_ops = {
2062 .free = ffs_fs_free_fc,
2063 .parse_param = ffs_fs_parse_param,
2064 .get_tree = ffs_fs_get_tree,
2065 };
2066
ffs_fs_init_fs_context(struct fs_context * fc)2067 static int ffs_fs_init_fs_context(struct fs_context *fc)
2068 {
2069 struct ffs_sb_fill_data *ctx;
2070
2071 ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
2072 if (!ctx)
2073 return -ENOMEM;
2074
2075 ctx->perms.mode = S_IFREG | 0600;
2076 ctx->perms.uid = GLOBAL_ROOT_UID;
2077 ctx->perms.gid = GLOBAL_ROOT_GID;
2078 ctx->root_mode = S_IFDIR | 0500;
2079 ctx->no_disconnect = false;
2080
2081 fc->fs_private = ctx;
2082 fc->ops = &ffs_fs_context_ops;
2083 return 0;
2084 }
2085
2086 static void
ffs_fs_kill_sb(struct super_block * sb)2087 ffs_fs_kill_sb(struct super_block *sb)
2088 {
2089 kill_litter_super(sb);
2090 if (sb->s_fs_info)
2091 ffs_data_closed(sb->s_fs_info);
2092 }
2093
2094 static struct file_system_type ffs_fs_type = {
2095 .owner = THIS_MODULE,
2096 .name = "functionfs",
2097 .init_fs_context = ffs_fs_init_fs_context,
2098 .parameters = ffs_fs_fs_parameters,
2099 .kill_sb = ffs_fs_kill_sb,
2100 };
2101 MODULE_ALIAS_FS("functionfs");
2102
2103
2104 /* Driver's main init/cleanup functions *************************************/
2105
functionfs_init(void)2106 static int functionfs_init(void)
2107 {
2108 int ret;
2109
2110 ret = register_filesystem(&ffs_fs_type);
2111 if (!ret)
2112 pr_info("file system registered\n");
2113 else
2114 pr_err("failed registering file system (%d)\n", ret);
2115
2116 return ret;
2117 }
2118
functionfs_cleanup(void)2119 static void functionfs_cleanup(void)
2120 {
2121 pr_info("unloading\n");
2122 unregister_filesystem(&ffs_fs_type);
2123 }
2124
2125
2126 /* ffs_data and ffs_function construction and destruction code **************/
2127
2128 static void ffs_data_clear(struct ffs_data *ffs);
2129 static void ffs_data_reset(struct ffs_data *ffs);
2130
ffs_data_get(struct ffs_data * ffs)2131 static void ffs_data_get(struct ffs_data *ffs)
2132 {
2133 refcount_inc(&ffs->ref);
2134 }
2135
ffs_data_opened(struct ffs_data * ffs)2136 static void ffs_data_opened(struct ffs_data *ffs)
2137 {
2138 refcount_inc(&ffs->ref);
2139 if (atomic_add_return(1, &ffs->opened) == 1 &&
2140 ffs->state == FFS_DEACTIVATED) {
2141 ffs->state = FFS_CLOSING;
2142 ffs_data_reset(ffs);
2143 }
2144 }
2145
ffs_data_put(struct ffs_data * ffs)2146 static void ffs_data_put(struct ffs_data *ffs)
2147 {
2148 if (refcount_dec_and_test(&ffs->ref)) {
2149 pr_info("%s(): freeing\n", __func__);
2150 ffs_data_clear(ffs);
2151 ffs_release_dev(ffs->private_data);
2152 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
2153 swait_active(&ffs->ep0req_completion.wait) ||
2154 waitqueue_active(&ffs->wait));
2155 destroy_workqueue(ffs->io_completion_wq);
2156 kfree(ffs->dev_name);
2157 kfree(ffs);
2158 }
2159 }
2160
ffs_data_closed(struct ffs_data * ffs)2161 static void ffs_data_closed(struct ffs_data *ffs)
2162 {
2163 struct ffs_epfile *epfiles;
2164 unsigned long flags;
2165
2166 if (atomic_dec_and_test(&ffs->opened)) {
2167 if (ffs->no_disconnect) {
2168 ffs->state = FFS_DEACTIVATED;
2169 spin_lock_irqsave(&ffs->eps_lock, flags);
2170 epfiles = ffs->epfiles;
2171 ffs->epfiles = NULL;
2172 spin_unlock_irqrestore(&ffs->eps_lock,
2173 flags);
2174
2175 if (epfiles)
2176 ffs_epfiles_destroy(epfiles,
2177 ffs->eps_count);
2178
2179 if (ffs->setup_state == FFS_SETUP_PENDING)
2180 __ffs_ep0_stall(ffs);
2181 } else {
2182 ffs->state = FFS_CLOSING;
2183 ffs_data_reset(ffs);
2184 }
2185 }
2186 if (atomic_read(&ffs->opened) < 0) {
2187 ffs->state = FFS_CLOSING;
2188 ffs_data_reset(ffs);
2189 }
2190
2191 ffs_data_put(ffs);
2192 }
2193
ffs_data_new(const char * dev_name)2194 static struct ffs_data *ffs_data_new(const char *dev_name)
2195 {
2196 struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
2197 if (!ffs)
2198 return NULL;
2199
2200 ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
2201 if (!ffs->io_completion_wq) {
2202 kfree(ffs);
2203 return NULL;
2204 }
2205
2206 refcount_set(&ffs->ref, 1);
2207 atomic_set(&ffs->opened, 0);
2208 ffs->state = FFS_READ_DESCRIPTORS;
2209 mutex_init(&ffs->mutex);
2210 spin_lock_init(&ffs->eps_lock);
2211 init_waitqueue_head(&ffs->ev.waitq);
2212 init_waitqueue_head(&ffs->wait);
2213 init_completion(&ffs->ep0req_completion);
2214
2215 /* XXX REVISIT need to update it in some places, or do we? */
2216 ffs->ev.can_stall = 1;
2217
2218 return ffs;
2219 }
2220
ffs_data_clear(struct ffs_data * ffs)2221 static void ffs_data_clear(struct ffs_data *ffs)
2222 {
2223 struct ffs_epfile *epfiles;
2224 unsigned long flags;
2225
2226 ffs_closed(ffs);
2227
2228 BUG_ON(ffs->gadget);
2229
2230 spin_lock_irqsave(&ffs->eps_lock, flags);
2231 epfiles = ffs->epfiles;
2232 ffs->epfiles = NULL;
2233 spin_unlock_irqrestore(&ffs->eps_lock, flags);
2234
2235 /*
2236 * potential race possible between ffs_func_eps_disable
2237 * & ffs_epfile_release therefore maintaining a local
2238 * copy of epfile will save us from use-after-free.
2239 */
2240 if (epfiles) {
2241 ffs_epfiles_destroy(epfiles, ffs->eps_count);
2242 ffs->epfiles = NULL;
2243 }
2244
2245 if (ffs->ffs_eventfd) {
2246 eventfd_ctx_put(ffs->ffs_eventfd);
2247 ffs->ffs_eventfd = NULL;
2248 }
2249
2250 kfree(ffs->raw_descs_data);
2251 kfree(ffs->raw_strings);
2252 kfree(ffs->stringtabs);
2253 }
2254
ffs_data_reset(struct ffs_data * ffs)2255 static void ffs_data_reset(struct ffs_data *ffs)
2256 {
2257 ffs_data_clear(ffs);
2258
2259 ffs->raw_descs_data = NULL;
2260 ffs->raw_descs = NULL;
2261 ffs->raw_strings = NULL;
2262 ffs->stringtabs = NULL;
2263
2264 ffs->raw_descs_length = 0;
2265 ffs->fs_descs_count = 0;
2266 ffs->hs_descs_count = 0;
2267 ffs->ss_descs_count = 0;
2268
2269 ffs->strings_count = 0;
2270 ffs->interfaces_count = 0;
2271 ffs->eps_count = 0;
2272
2273 ffs->ev.count = 0;
2274
2275 ffs->state = FFS_READ_DESCRIPTORS;
2276 ffs->setup_state = FFS_NO_SETUP;
2277 ffs->flags = 0;
2278
2279 ffs->ms_os_descs_ext_prop_count = 0;
2280 ffs->ms_os_descs_ext_prop_name_len = 0;
2281 ffs->ms_os_descs_ext_prop_data_len = 0;
2282 }
2283
2284
functionfs_bind(struct ffs_data * ffs,struct usb_composite_dev * cdev)2285 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
2286 {
2287 struct usb_gadget_strings **lang;
2288 int first_id;
2289
2290 if (WARN_ON(ffs->state != FFS_ACTIVE
2291 || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
2292 return -EBADFD;
2293
2294 first_id = usb_string_ids_n(cdev, ffs->strings_count);
2295 if (first_id < 0)
2296 return first_id;
2297
2298 ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
2299 if (!ffs->ep0req)
2300 return -ENOMEM;
2301 ffs->ep0req->complete = ffs_ep0_complete;
2302 ffs->ep0req->context = ffs;
2303
2304 lang = ffs->stringtabs;
2305 if (lang) {
2306 for (; *lang; ++lang) {
2307 struct usb_string *str = (*lang)->strings;
2308 int id = first_id;
2309 for (; str->s; ++id, ++str)
2310 str->id = id;
2311 }
2312 }
2313
2314 ffs->gadget = cdev->gadget;
2315 ffs_data_get(ffs);
2316 return 0;
2317 }
2318
functionfs_unbind(struct ffs_data * ffs)2319 static void functionfs_unbind(struct ffs_data *ffs)
2320 {
2321 if (!WARN_ON(!ffs->gadget)) {
2322 /* dequeue before freeing ep0req */
2323 usb_ep_dequeue(ffs->gadget->ep0, ffs->ep0req);
2324 mutex_lock(&ffs->mutex);
2325 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
2326 ffs->ep0req = NULL;
2327 ffs->gadget = NULL;
2328 clear_bit(FFS_FL_BOUND, &ffs->flags);
2329 mutex_unlock(&ffs->mutex);
2330 ffs_data_put(ffs);
2331 }
2332 }
2333
ffs_epfiles_create(struct ffs_data * ffs)2334 static int ffs_epfiles_create(struct ffs_data *ffs)
2335 {
2336 struct ffs_epfile *epfile, *epfiles;
2337 unsigned i, count;
2338
2339 count = ffs->eps_count;
2340 epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
2341 if (!epfiles)
2342 return -ENOMEM;
2343
2344 epfile = epfiles;
2345 for (i = 1; i <= count; ++i, ++epfile) {
2346 epfile->ffs = ffs;
2347 mutex_init(&epfile->mutex);
2348 mutex_init(&epfile->dmabufs_mutex);
2349 INIT_LIST_HEAD(&epfile->dmabufs);
2350 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2351 sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
2352 else
2353 sprintf(epfile->name, "ep%u", i);
2354 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
2355 epfile,
2356 &ffs_epfile_operations);
2357 if (!epfile->dentry) {
2358 ffs_epfiles_destroy(epfiles, i - 1);
2359 return -ENOMEM;
2360 }
2361 }
2362
2363 ffs->epfiles = epfiles;
2364 return 0;
2365 }
2366
ffs_epfiles_destroy(struct ffs_epfile * epfiles,unsigned count)2367 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
2368 {
2369 struct ffs_epfile *epfile = epfiles;
2370
2371 for (; count; --count, ++epfile) {
2372 BUG_ON(mutex_is_locked(&epfile->mutex));
2373 if (epfile->dentry) {
2374 d_delete(epfile->dentry);
2375 dput(epfile->dentry);
2376 epfile->dentry = NULL;
2377 }
2378 }
2379
2380 kfree(epfiles);
2381 }
2382
ffs_func_eps_disable(struct ffs_function * func)2383 static void ffs_func_eps_disable(struct ffs_function *func)
2384 {
2385 struct ffs_ep *ep;
2386 struct ffs_epfile *epfile;
2387 unsigned short count;
2388 unsigned long flags;
2389
2390 spin_lock_irqsave(&func->ffs->eps_lock, flags);
2391 count = func->ffs->eps_count;
2392 epfile = func->ffs->epfiles;
2393 ep = func->eps;
2394 while (count--) {
2395 /* pending requests get nuked */
2396 if (ep->ep)
2397 usb_ep_disable(ep->ep);
2398 ++ep;
2399
2400 if (epfile) {
2401 epfile->ep = NULL;
2402 __ffs_epfile_read_buffer_free(epfile);
2403 ++epfile;
2404 }
2405 }
2406 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2407 }
2408
ffs_func_eps_enable(struct ffs_function * func)2409 static int ffs_func_eps_enable(struct ffs_function *func)
2410 {
2411 struct ffs_data *ffs;
2412 struct ffs_ep *ep;
2413 struct ffs_epfile *epfile;
2414 unsigned short count;
2415 unsigned long flags;
2416 int ret = 0;
2417
2418 spin_lock_irqsave(&func->ffs->eps_lock, flags);
2419 ffs = func->ffs;
2420 ep = func->eps;
2421 epfile = ffs->epfiles;
2422 count = ffs->eps_count;
2423 while(count--) {
2424 ep->ep->driver_data = ep;
2425
2426 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
2427 if (ret) {
2428 pr_err("%s: config_ep_by_speed(%s) returned %d\n",
2429 __func__, ep->ep->name, ret);
2430 break;
2431 }
2432
2433 ret = usb_ep_enable(ep->ep);
2434 if (!ret) {
2435 epfile->ep = ep;
2436 epfile->in = usb_endpoint_dir_in(ep->ep->desc);
2437 epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
2438 } else {
2439 break;
2440 }
2441
2442 ++ep;
2443 ++epfile;
2444 }
2445
2446 wake_up_interruptible(&ffs->wait);
2447 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2448
2449 return ret;
2450 }
2451
2452
2453 /* Parsing and building descriptors and strings *****************************/
2454
2455 /*
2456 * This validates if data pointed by data is a valid USB descriptor as
2457 * well as record how many interfaces, endpoints and strings are
2458 * required by given configuration. Returns address after the
2459 * descriptor or NULL if data is invalid.
2460 */
2461
2462 enum ffs_entity_type {
2463 FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
2464 };
2465
2466 enum ffs_os_desc_type {
2467 FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
2468 };
2469
2470 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2471 u8 *valuep,
2472 struct usb_descriptor_header *desc,
2473 void *priv);
2474
2475 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2476 struct usb_os_desc_header *h, void *data,
2477 unsigned len, void *priv);
2478
ffs_do_single_desc(char * data,unsigned len,ffs_entity_callback entity,void * priv,int * current_class)2479 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2480 ffs_entity_callback entity,
2481 void *priv, int *current_class)
2482 {
2483 struct usb_descriptor_header *_ds = (void *)data;
2484 u8 length;
2485 int ret;
2486
2487 /* At least two bytes are required: length and type */
2488 if (len < 2) {
2489 pr_vdebug("descriptor too short\n");
2490 return -EINVAL;
2491 }
2492
2493 /* If we have at least as many bytes as the descriptor takes? */
2494 length = _ds->bLength;
2495 if (len < length) {
2496 pr_vdebug("descriptor longer then available data\n");
2497 return -EINVAL;
2498 }
2499
2500 #define __entity_check_INTERFACE(val) 1
2501 #define __entity_check_STRING(val) (val)
2502 #define __entity_check_ENDPOINT(val) ((val) & USB_ENDPOINT_NUMBER_MASK)
2503 #define __entity(type, val) do { \
2504 pr_vdebug("entity " #type "(%02x)\n", (val)); \
2505 if (!__entity_check_ ##type(val)) { \
2506 pr_vdebug("invalid entity's value\n"); \
2507 return -EINVAL; \
2508 } \
2509 ret = entity(FFS_ ##type, &val, _ds, priv); \
2510 if (ret < 0) { \
2511 pr_debug("entity " #type "(%02x); ret = %d\n", \
2512 (val), ret); \
2513 return ret; \
2514 } \
2515 } while (0)
2516
2517 /* Parse descriptor depending on type. */
2518 switch (_ds->bDescriptorType) {
2519 case USB_DT_DEVICE:
2520 case USB_DT_CONFIG:
2521 case USB_DT_STRING:
2522 case USB_DT_DEVICE_QUALIFIER:
2523 /* function can't have any of those */
2524 pr_vdebug("descriptor reserved for gadget: %d\n",
2525 _ds->bDescriptorType);
2526 return -EINVAL;
2527
2528 case USB_DT_INTERFACE: {
2529 struct usb_interface_descriptor *ds = (void *)_ds;
2530 pr_vdebug("interface descriptor\n");
2531 if (length != sizeof *ds)
2532 goto inv_length;
2533
2534 __entity(INTERFACE, ds->bInterfaceNumber);
2535 if (ds->iInterface)
2536 __entity(STRING, ds->iInterface);
2537 *current_class = ds->bInterfaceClass;
2538 }
2539 break;
2540
2541 case USB_DT_ENDPOINT: {
2542 struct usb_endpoint_descriptor *ds = (void *)_ds;
2543 pr_vdebug("endpoint descriptor\n");
2544 if (length != USB_DT_ENDPOINT_SIZE &&
2545 length != USB_DT_ENDPOINT_AUDIO_SIZE)
2546 goto inv_length;
2547 __entity(ENDPOINT, ds->bEndpointAddress);
2548 }
2549 break;
2550
2551 case USB_TYPE_CLASS | 0x01:
2552 if (*current_class == USB_INTERFACE_CLASS_HID) {
2553 pr_vdebug("hid descriptor\n");
2554 if (length != sizeof(struct hid_descriptor))
2555 goto inv_length;
2556 break;
2557 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2558 pr_vdebug("ccid descriptor\n");
2559 if (length != sizeof(struct ccid_descriptor))
2560 goto inv_length;
2561 break;
2562 } else {
2563 pr_vdebug("unknown descriptor: %d for class %d\n",
2564 _ds->bDescriptorType, *current_class);
2565 return -EINVAL;
2566 }
2567
2568 case USB_DT_OTG:
2569 if (length != sizeof(struct usb_otg_descriptor))
2570 goto inv_length;
2571 break;
2572
2573 case USB_DT_INTERFACE_ASSOCIATION: {
2574 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2575 pr_vdebug("interface association descriptor\n");
2576 if (length != sizeof *ds)
2577 goto inv_length;
2578 if (ds->iFunction)
2579 __entity(STRING, ds->iFunction);
2580 }
2581 break;
2582
2583 case USB_DT_SS_ENDPOINT_COMP:
2584 pr_vdebug("EP SS companion descriptor\n");
2585 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2586 goto inv_length;
2587 break;
2588
2589 case USB_DT_OTHER_SPEED_CONFIG:
2590 case USB_DT_INTERFACE_POWER:
2591 case USB_DT_DEBUG:
2592 case USB_DT_SECURITY:
2593 case USB_DT_CS_RADIO_CONTROL:
2594 /* TODO */
2595 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2596 return -EINVAL;
2597
2598 default:
2599 /* We should never be here */
2600 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2601 return -EINVAL;
2602
2603 inv_length:
2604 pr_vdebug("invalid length: %d (descriptor %d)\n",
2605 _ds->bLength, _ds->bDescriptorType);
2606 return -EINVAL;
2607 }
2608
2609 #undef __entity
2610 #undef __entity_check_DESCRIPTOR
2611 #undef __entity_check_INTERFACE
2612 #undef __entity_check_STRING
2613 #undef __entity_check_ENDPOINT
2614
2615 return length;
2616 }
2617
ffs_do_descs(unsigned count,char * data,unsigned len,ffs_entity_callback entity,void * priv)2618 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2619 ffs_entity_callback entity, void *priv)
2620 {
2621 const unsigned _len = len;
2622 unsigned long num = 0;
2623 int current_class = -1;
2624
2625 for (;;) {
2626 int ret;
2627
2628 if (num == count)
2629 data = NULL;
2630
2631 /* Record "descriptor" entity */
2632 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2633 if (ret < 0) {
2634 pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2635 num, ret);
2636 return ret;
2637 }
2638
2639 if (!data)
2640 return _len - len;
2641
2642 ret = ffs_do_single_desc(data, len, entity, priv,
2643 ¤t_class);
2644 if (ret < 0) {
2645 pr_debug("%s returns %d\n", __func__, ret);
2646 return ret;
2647 }
2648
2649 len -= ret;
2650 data += ret;
2651 ++num;
2652 }
2653 }
2654
__ffs_data_do_entity(enum ffs_entity_type type,u8 * valuep,struct usb_descriptor_header * desc,void * priv)2655 static int __ffs_data_do_entity(enum ffs_entity_type type,
2656 u8 *valuep, struct usb_descriptor_header *desc,
2657 void *priv)
2658 {
2659 struct ffs_desc_helper *helper = priv;
2660 struct usb_endpoint_descriptor *d;
2661
2662 switch (type) {
2663 case FFS_DESCRIPTOR:
2664 break;
2665
2666 case FFS_INTERFACE:
2667 /*
2668 * Interfaces are indexed from zero so if we
2669 * encountered interface "n" then there are at least
2670 * "n+1" interfaces.
2671 */
2672 if (*valuep >= helper->interfaces_count)
2673 helper->interfaces_count = *valuep + 1;
2674 break;
2675
2676 case FFS_STRING:
2677 /*
2678 * Strings are indexed from 1 (0 is reserved
2679 * for languages list)
2680 */
2681 if (*valuep > helper->ffs->strings_count)
2682 helper->ffs->strings_count = *valuep;
2683 break;
2684
2685 case FFS_ENDPOINT:
2686 d = (void *)desc;
2687 helper->eps_count++;
2688 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2689 return -EINVAL;
2690 /* Check if descriptors for any speed were already parsed */
2691 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2692 helper->ffs->eps_addrmap[helper->eps_count] =
2693 d->bEndpointAddress;
2694 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2695 d->bEndpointAddress)
2696 return -EINVAL;
2697 break;
2698 }
2699
2700 return 0;
2701 }
2702
__ffs_do_os_desc_header(enum ffs_os_desc_type * next_type,struct usb_os_desc_header * desc)2703 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2704 struct usb_os_desc_header *desc)
2705 {
2706 u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2707 u16 w_index = le16_to_cpu(desc->wIndex);
2708
2709 if (bcd_version == 0x1) {
2710 pr_warn("bcdVersion must be 0x0100, stored in Little Endian order. "
2711 "Userspace driver should be fixed, accepting 0x0001 for compatibility.\n");
2712 } else if (bcd_version != 0x100) {
2713 pr_vdebug("unsupported os descriptors version: 0x%x\n",
2714 bcd_version);
2715 return -EINVAL;
2716 }
2717 switch (w_index) {
2718 case 0x4:
2719 *next_type = FFS_OS_DESC_EXT_COMPAT;
2720 break;
2721 case 0x5:
2722 *next_type = FFS_OS_DESC_EXT_PROP;
2723 break;
2724 default:
2725 pr_vdebug("unsupported os descriptor type: %d", w_index);
2726 return -EINVAL;
2727 }
2728
2729 return sizeof(*desc);
2730 }
2731
2732 /*
2733 * Process all extended compatibility/extended property descriptors
2734 * of a feature descriptor
2735 */
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)2736 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2737 enum ffs_os_desc_type type,
2738 u16 feature_count,
2739 ffs_os_desc_callback entity,
2740 void *priv,
2741 struct usb_os_desc_header *h)
2742 {
2743 int ret;
2744 const unsigned _len = len;
2745
2746 /* loop over all ext compat/ext prop descriptors */
2747 while (feature_count--) {
2748 ret = entity(type, h, data, len, priv);
2749 if (ret < 0) {
2750 pr_debug("bad OS descriptor, type: %d\n", type);
2751 return ret;
2752 }
2753 data += ret;
2754 len -= ret;
2755 }
2756 return _len - len;
2757 }
2758
2759 /* 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)2760 static int __must_check ffs_do_os_descs(unsigned count,
2761 char *data, unsigned len,
2762 ffs_os_desc_callback entity, void *priv)
2763 {
2764 const unsigned _len = len;
2765 unsigned long num = 0;
2766
2767 for (num = 0; num < count; ++num) {
2768 int ret;
2769 enum ffs_os_desc_type type;
2770 u16 feature_count;
2771 struct usb_os_desc_header *desc = (void *)data;
2772
2773 if (len < sizeof(*desc))
2774 return -EINVAL;
2775
2776 /*
2777 * Record "descriptor" entity.
2778 * Process dwLength, bcdVersion, wIndex, get b/wCount.
2779 * Move the data pointer to the beginning of extended
2780 * compatibilities proper or extended properties proper
2781 * portions of the data
2782 */
2783 if (le32_to_cpu(desc->dwLength) > len)
2784 return -EINVAL;
2785
2786 ret = __ffs_do_os_desc_header(&type, desc);
2787 if (ret < 0) {
2788 pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2789 num, ret);
2790 return ret;
2791 }
2792 /*
2793 * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2794 */
2795 feature_count = le16_to_cpu(desc->wCount);
2796 if (type == FFS_OS_DESC_EXT_COMPAT &&
2797 (feature_count > 255 || desc->Reserved))
2798 return -EINVAL;
2799 len -= ret;
2800 data += ret;
2801
2802 /*
2803 * Process all function/property descriptors
2804 * of this Feature Descriptor
2805 */
2806 ret = ffs_do_single_os_desc(data, len, type,
2807 feature_count, entity, priv, desc);
2808 if (ret < 0) {
2809 pr_debug("%s returns %d\n", __func__, ret);
2810 return ret;
2811 }
2812
2813 len -= ret;
2814 data += ret;
2815 }
2816 return _len - len;
2817 }
2818
2819 /*
2820 * Validate contents of the buffer from userspace related to OS descriptors.
2821 */
__ffs_data_do_os_desc(enum ffs_os_desc_type type,struct usb_os_desc_header * h,void * data,unsigned len,void * priv)2822 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2823 struct usb_os_desc_header *h, void *data,
2824 unsigned len, void *priv)
2825 {
2826 struct ffs_data *ffs = priv;
2827 u8 length;
2828
2829 switch (type) {
2830 case FFS_OS_DESC_EXT_COMPAT: {
2831 struct usb_ext_compat_desc *d = data;
2832 int i;
2833
2834 if (len < sizeof(*d) ||
2835 d->bFirstInterfaceNumber >= ffs->interfaces_count)
2836 return -EINVAL;
2837 if (d->Reserved1 != 1) {
2838 /*
2839 * According to the spec, Reserved1 must be set to 1
2840 * but older kernels incorrectly rejected non-zero
2841 * values. We fix it here to avoid returning EINVAL
2842 * in response to values we used to accept.
2843 */
2844 pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2845 d->Reserved1 = 1;
2846 }
2847 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2848 if (d->Reserved2[i])
2849 return -EINVAL;
2850
2851 length = sizeof(struct usb_ext_compat_desc);
2852 }
2853 break;
2854 case FFS_OS_DESC_EXT_PROP: {
2855 struct usb_ext_prop_desc *d = data;
2856 u32 type, pdl;
2857 u16 pnl;
2858
2859 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2860 return -EINVAL;
2861 length = le32_to_cpu(d->dwSize);
2862 if (len < length)
2863 return -EINVAL;
2864 type = le32_to_cpu(d->dwPropertyDataType);
2865 if (type < USB_EXT_PROP_UNICODE ||
2866 type > USB_EXT_PROP_UNICODE_MULTI) {
2867 pr_vdebug("unsupported os descriptor property type: %d",
2868 type);
2869 return -EINVAL;
2870 }
2871 pnl = le16_to_cpu(d->wPropertyNameLength);
2872 if (length < 14 + pnl) {
2873 pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2874 length, pnl, type);
2875 return -EINVAL;
2876 }
2877 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2878 if (length != 14 + pnl + pdl) {
2879 pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2880 length, pnl, pdl, type);
2881 return -EINVAL;
2882 }
2883 ++ffs->ms_os_descs_ext_prop_count;
2884 /* property name reported to the host as "WCHAR"s */
2885 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2886 ffs->ms_os_descs_ext_prop_data_len += pdl;
2887 }
2888 break;
2889 default:
2890 pr_vdebug("unknown descriptor: %d\n", type);
2891 return -EINVAL;
2892 }
2893 return length;
2894 }
2895
__ffs_data_got_descs(struct ffs_data * ffs,char * const _data,size_t len)2896 static int __ffs_data_got_descs(struct ffs_data *ffs,
2897 char *const _data, size_t len)
2898 {
2899 char *data = _data, *raw_descs;
2900 unsigned os_descs_count = 0, counts[3], flags;
2901 int ret = -EINVAL, i;
2902 struct ffs_desc_helper helper;
2903
2904 if (get_unaligned_le32(data + 4) != len)
2905 goto error;
2906
2907 switch (get_unaligned_le32(data)) {
2908 case FUNCTIONFS_DESCRIPTORS_MAGIC:
2909 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2910 data += 8;
2911 len -= 8;
2912 break;
2913 case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2914 flags = get_unaligned_le32(data + 8);
2915 ffs->user_flags = flags;
2916 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2917 FUNCTIONFS_HAS_HS_DESC |
2918 FUNCTIONFS_HAS_SS_DESC |
2919 FUNCTIONFS_HAS_MS_OS_DESC |
2920 FUNCTIONFS_VIRTUAL_ADDR |
2921 FUNCTIONFS_EVENTFD |
2922 FUNCTIONFS_ALL_CTRL_RECIP |
2923 FUNCTIONFS_CONFIG0_SETUP)) {
2924 ret = -ENOSYS;
2925 goto error;
2926 }
2927 data += 12;
2928 len -= 12;
2929 break;
2930 default:
2931 goto error;
2932 }
2933
2934 if (flags & FUNCTIONFS_EVENTFD) {
2935 if (len < 4)
2936 goto error;
2937 ffs->ffs_eventfd =
2938 eventfd_ctx_fdget((int)get_unaligned_le32(data));
2939 if (IS_ERR(ffs->ffs_eventfd)) {
2940 ret = PTR_ERR(ffs->ffs_eventfd);
2941 ffs->ffs_eventfd = NULL;
2942 goto error;
2943 }
2944 data += 4;
2945 len -= 4;
2946 }
2947
2948 /* Read fs_count, hs_count and ss_count (if present) */
2949 for (i = 0; i < 3; ++i) {
2950 if (!(flags & (1 << i))) {
2951 counts[i] = 0;
2952 } else if (len < 4) {
2953 goto error;
2954 } else {
2955 counts[i] = get_unaligned_le32(data);
2956 data += 4;
2957 len -= 4;
2958 }
2959 }
2960 if (flags & (1 << i)) {
2961 if (len < 4) {
2962 goto error;
2963 }
2964 os_descs_count = get_unaligned_le32(data);
2965 data += 4;
2966 len -= 4;
2967 }
2968
2969 /* Read descriptors */
2970 raw_descs = data;
2971 helper.ffs = ffs;
2972 for (i = 0; i < 3; ++i) {
2973 if (!counts[i])
2974 continue;
2975 helper.interfaces_count = 0;
2976 helper.eps_count = 0;
2977 ret = ffs_do_descs(counts[i], data, len,
2978 __ffs_data_do_entity, &helper);
2979 if (ret < 0)
2980 goto error;
2981 if (!ffs->eps_count && !ffs->interfaces_count) {
2982 ffs->eps_count = helper.eps_count;
2983 ffs->interfaces_count = helper.interfaces_count;
2984 } else {
2985 if (ffs->eps_count != helper.eps_count) {
2986 ret = -EINVAL;
2987 goto error;
2988 }
2989 if (ffs->interfaces_count != helper.interfaces_count) {
2990 ret = -EINVAL;
2991 goto error;
2992 }
2993 }
2994 data += ret;
2995 len -= ret;
2996 }
2997 if (os_descs_count) {
2998 ret = ffs_do_os_descs(os_descs_count, data, len,
2999 __ffs_data_do_os_desc, ffs);
3000 if (ret < 0)
3001 goto error;
3002 data += ret;
3003 len -= ret;
3004 }
3005
3006 if (raw_descs == data || len) {
3007 ret = -EINVAL;
3008 goto error;
3009 }
3010
3011 ffs->raw_descs_data = _data;
3012 ffs->raw_descs = raw_descs;
3013 ffs->raw_descs_length = data - raw_descs;
3014 ffs->fs_descs_count = counts[0];
3015 ffs->hs_descs_count = counts[1];
3016 ffs->ss_descs_count = counts[2];
3017 ffs->ms_os_descs_count = os_descs_count;
3018
3019 return 0;
3020
3021 error:
3022 kfree(_data);
3023 return ret;
3024 }
3025
__ffs_data_got_strings(struct ffs_data * ffs,char * const _data,size_t len)3026 static int __ffs_data_got_strings(struct ffs_data *ffs,
3027 char *const _data, size_t len)
3028 {
3029 u32 str_count, needed_count, lang_count;
3030 struct usb_gadget_strings **stringtabs, *t;
3031 const char *data = _data;
3032 struct usb_string *s;
3033
3034 if (len < 16 ||
3035 get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
3036 get_unaligned_le32(data + 4) != len)
3037 goto error;
3038 str_count = get_unaligned_le32(data + 8);
3039 lang_count = get_unaligned_le32(data + 12);
3040
3041 /* if one is zero the other must be zero */
3042 if (!str_count != !lang_count)
3043 goto error;
3044
3045 /* Do we have at least as many strings as descriptors need? */
3046 needed_count = ffs->strings_count;
3047 if (str_count < needed_count)
3048 goto error;
3049
3050 /*
3051 * If we don't need any strings just return and free all
3052 * memory.
3053 */
3054 if (!needed_count) {
3055 kfree(_data);
3056 return 0;
3057 }
3058
3059 /* Allocate everything in one chunk so there's less maintenance. */
3060 {
3061 unsigned i = 0;
3062 vla_group(d);
3063 vla_item(d, struct usb_gadget_strings *, stringtabs,
3064 size_add(lang_count, 1));
3065 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
3066 vla_item(d, struct usb_string, strings,
3067 size_mul(lang_count, (needed_count + 1)));
3068
3069 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
3070
3071 if (!vlabuf) {
3072 kfree(_data);
3073 return -ENOMEM;
3074 }
3075
3076 /* Initialize the VLA pointers */
3077 stringtabs = vla_ptr(vlabuf, d, stringtabs);
3078 t = vla_ptr(vlabuf, d, stringtab);
3079 i = lang_count;
3080 do {
3081 *stringtabs++ = t++;
3082 } while (--i);
3083 *stringtabs = NULL;
3084
3085 /* stringtabs = vlabuf = d_stringtabs for later kfree */
3086 stringtabs = vla_ptr(vlabuf, d, stringtabs);
3087 t = vla_ptr(vlabuf, d, stringtab);
3088 s = vla_ptr(vlabuf, d, strings);
3089 }
3090
3091 /* For each language */
3092 data += 16;
3093 len -= 16;
3094
3095 do { /* lang_count > 0 so we can use do-while */
3096 unsigned needed = needed_count;
3097 u32 str_per_lang = str_count;
3098
3099 if (len < 3)
3100 goto error_free;
3101 t->language = get_unaligned_le16(data);
3102 t->strings = s;
3103 ++t;
3104
3105 data += 2;
3106 len -= 2;
3107
3108 /* For each string */
3109 do { /* str_count > 0 so we can use do-while */
3110 size_t length = strnlen(data, len);
3111
3112 if (length == len)
3113 goto error_free;
3114
3115 /*
3116 * User may provide more strings then we need,
3117 * if that's the case we simply ignore the
3118 * rest
3119 */
3120 if (needed) {
3121 /*
3122 * s->id will be set while adding
3123 * function to configuration so for
3124 * now just leave garbage here.
3125 */
3126 s->s = data;
3127 --needed;
3128 ++s;
3129 }
3130
3131 data += length + 1;
3132 len -= length + 1;
3133 } while (--str_per_lang);
3134
3135 s->id = 0; /* terminator */
3136 s->s = NULL;
3137 ++s;
3138
3139 } while (--lang_count);
3140
3141 /* Some garbage left? */
3142 if (len)
3143 goto error_free;
3144
3145 /* Done! */
3146 ffs->stringtabs = stringtabs;
3147 ffs->raw_strings = _data;
3148
3149 return 0;
3150
3151 error_free:
3152 kfree(stringtabs);
3153 error:
3154 kfree(_data);
3155 return -EINVAL;
3156 }
3157
3158
3159 /* Events handling and management *******************************************/
3160
__ffs_event_add(struct ffs_data * ffs,enum usb_functionfs_event_type type)3161 static void __ffs_event_add(struct ffs_data *ffs,
3162 enum usb_functionfs_event_type type)
3163 {
3164 enum usb_functionfs_event_type rem_type1, rem_type2 = type;
3165 int neg = 0;
3166
3167 /*
3168 * Abort any unhandled setup
3169 *
3170 * We do not need to worry about some cmpxchg() changing value
3171 * of ffs->setup_state without holding the lock because when
3172 * state is FFS_SETUP_PENDING cmpxchg() in several places in
3173 * the source does nothing.
3174 */
3175 if (ffs->setup_state == FFS_SETUP_PENDING)
3176 ffs->setup_state = FFS_SETUP_CANCELLED;
3177
3178 /*
3179 * Logic of this function guarantees that there are at most four pending
3180 * evens on ffs->ev.types queue. This is important because the queue
3181 * has space for four elements only and __ffs_ep0_read_events function
3182 * depends on that limit as well. If more event types are added, those
3183 * limits have to be revisited or guaranteed to still hold.
3184 */
3185 switch (type) {
3186 case FUNCTIONFS_RESUME:
3187 rem_type2 = FUNCTIONFS_SUSPEND;
3188 fallthrough;
3189 case FUNCTIONFS_SUSPEND:
3190 case FUNCTIONFS_SETUP:
3191 rem_type1 = type;
3192 /* Discard all similar events */
3193 break;
3194
3195 case FUNCTIONFS_BIND:
3196 case FUNCTIONFS_UNBIND:
3197 case FUNCTIONFS_DISABLE:
3198 case FUNCTIONFS_ENABLE:
3199 /* Discard everything other then power management. */
3200 rem_type1 = FUNCTIONFS_SUSPEND;
3201 rem_type2 = FUNCTIONFS_RESUME;
3202 neg = 1;
3203 break;
3204
3205 default:
3206 WARN(1, "%d: unknown event, this should not happen\n", type);
3207 return;
3208 }
3209
3210 {
3211 u8 *ev = ffs->ev.types, *out = ev;
3212 unsigned n = ffs->ev.count;
3213 for (; n; --n, ++ev)
3214 if ((*ev == rem_type1 || *ev == rem_type2) == neg)
3215 *out++ = *ev;
3216 else
3217 pr_vdebug("purging event %d\n", *ev);
3218 ffs->ev.count = out - ffs->ev.types;
3219 }
3220
3221 pr_vdebug("adding event %d\n", type);
3222 ffs->ev.types[ffs->ev.count++] = type;
3223 wake_up_locked(&ffs->ev.waitq);
3224 if (ffs->ffs_eventfd)
3225 eventfd_signal(ffs->ffs_eventfd);
3226 }
3227
ffs_event_add(struct ffs_data * ffs,enum usb_functionfs_event_type type)3228 static void ffs_event_add(struct ffs_data *ffs,
3229 enum usb_functionfs_event_type type)
3230 {
3231 unsigned long flags;
3232 spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3233 __ffs_event_add(ffs, type);
3234 spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3235 }
3236
3237 /* Bind/unbind USB function hooks *******************************************/
3238
ffs_ep_addr2idx(struct ffs_data * ffs,u8 endpoint_address)3239 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
3240 {
3241 int i;
3242
3243 for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
3244 if (ffs->eps_addrmap[i] == endpoint_address)
3245 return i;
3246 return -ENOENT;
3247 }
3248
__ffs_func_bind_do_descs(enum ffs_entity_type type,u8 * valuep,struct usb_descriptor_header * desc,void * priv)3249 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
3250 struct usb_descriptor_header *desc,
3251 void *priv)
3252 {
3253 struct usb_endpoint_descriptor *ds = (void *)desc;
3254 struct ffs_function *func = priv;
3255 struct ffs_ep *ffs_ep;
3256 unsigned ep_desc_id;
3257 int idx;
3258 static const char *speed_names[] = { "full", "high", "super" };
3259
3260 if (type != FFS_DESCRIPTOR)
3261 return 0;
3262
3263 /*
3264 * If ss_descriptors is not NULL, we are reading super speed
3265 * descriptors; if hs_descriptors is not NULL, we are reading high
3266 * speed descriptors; otherwise, we are reading full speed
3267 * descriptors.
3268 */
3269 if (func->function.ss_descriptors) {
3270 ep_desc_id = 2;
3271 func->function.ss_descriptors[(long)valuep] = desc;
3272 } else if (func->function.hs_descriptors) {
3273 ep_desc_id = 1;
3274 func->function.hs_descriptors[(long)valuep] = desc;
3275 } else {
3276 ep_desc_id = 0;
3277 func->function.fs_descriptors[(long)valuep] = desc;
3278 }
3279
3280 if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
3281 return 0;
3282
3283 idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
3284 if (idx < 0)
3285 return idx;
3286
3287 ffs_ep = func->eps + idx;
3288
3289 if (ffs_ep->descs[ep_desc_id]) {
3290 pr_err("two %sspeed descriptors for EP %d\n",
3291 speed_names[ep_desc_id],
3292 ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
3293 return -EINVAL;
3294 }
3295 ffs_ep->descs[ep_desc_id] = ds;
3296
3297 ffs_dump_mem(": Original ep desc", ds, ds->bLength);
3298 if (ffs_ep->ep) {
3299 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
3300 if (!ds->wMaxPacketSize)
3301 ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
3302 } else {
3303 struct usb_request *req;
3304 struct usb_ep *ep;
3305 u8 bEndpointAddress;
3306 u16 wMaxPacketSize;
3307
3308 /*
3309 * We back up bEndpointAddress because autoconfig overwrites
3310 * it with physical endpoint address.
3311 */
3312 bEndpointAddress = ds->bEndpointAddress;
3313 /*
3314 * We back up wMaxPacketSize because autoconfig treats
3315 * endpoint descriptors as if they were full speed.
3316 */
3317 wMaxPacketSize = ds->wMaxPacketSize;
3318 pr_vdebug("autoconfig\n");
3319 ep = usb_ep_autoconfig(func->gadget, ds);
3320 if (!ep)
3321 return -ENOTSUPP;
3322 ep->driver_data = func->eps + idx;
3323
3324 req = usb_ep_alloc_request(ep, GFP_KERNEL);
3325 if (!req)
3326 return -ENOMEM;
3327
3328 ffs_ep->ep = ep;
3329 ffs_ep->req = req;
3330 func->eps_revmap[ds->bEndpointAddress &
3331 USB_ENDPOINT_NUMBER_MASK] = idx + 1;
3332 /*
3333 * If we use virtual address mapping, we restore
3334 * original bEndpointAddress value.
3335 */
3336 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3337 ds->bEndpointAddress = bEndpointAddress;
3338 /*
3339 * Restore wMaxPacketSize which was potentially
3340 * overwritten by autoconfig.
3341 */
3342 ds->wMaxPacketSize = wMaxPacketSize;
3343 }
3344 ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
3345
3346 return 0;
3347 }
3348
__ffs_func_bind_do_nums(enum ffs_entity_type type,u8 * valuep,struct usb_descriptor_header * desc,void * priv)3349 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
3350 struct usb_descriptor_header *desc,
3351 void *priv)
3352 {
3353 struct ffs_function *func = priv;
3354 unsigned idx;
3355 u8 newValue;
3356
3357 switch (type) {
3358 default:
3359 case FFS_DESCRIPTOR:
3360 /* Handled in previous pass by __ffs_func_bind_do_descs() */
3361 return 0;
3362
3363 case FFS_INTERFACE:
3364 idx = *valuep;
3365 if (func->interfaces_nums[idx] < 0) {
3366 int id = usb_interface_id(func->conf, &func->function);
3367 if (id < 0)
3368 return id;
3369 func->interfaces_nums[idx] = id;
3370 }
3371 newValue = func->interfaces_nums[idx];
3372 break;
3373
3374 case FFS_STRING:
3375 /* String' IDs are allocated when fsf_data is bound to cdev */
3376 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
3377 break;
3378
3379 case FFS_ENDPOINT:
3380 /*
3381 * USB_DT_ENDPOINT are handled in
3382 * __ffs_func_bind_do_descs().
3383 */
3384 if (desc->bDescriptorType == USB_DT_ENDPOINT)
3385 return 0;
3386
3387 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
3388 if (!func->eps[idx].ep)
3389 return -EINVAL;
3390
3391 {
3392 struct usb_endpoint_descriptor **descs;
3393 descs = func->eps[idx].descs;
3394 newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
3395 }
3396 break;
3397 }
3398
3399 pr_vdebug("%02x -> %02x\n", *valuep, newValue);
3400 *valuep = newValue;
3401 return 0;
3402 }
3403
__ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,struct usb_os_desc_header * h,void * data,unsigned len,void * priv)3404 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
3405 struct usb_os_desc_header *h, void *data,
3406 unsigned len, void *priv)
3407 {
3408 struct ffs_function *func = priv;
3409 u8 length = 0;
3410
3411 switch (type) {
3412 case FFS_OS_DESC_EXT_COMPAT: {
3413 struct usb_ext_compat_desc *desc = data;
3414 struct usb_os_desc_table *t;
3415
3416 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
3417 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
3418 memcpy(t->os_desc->ext_compat_id, &desc->IDs,
3419 sizeof_field(struct usb_ext_compat_desc, IDs));
3420 length = sizeof(*desc);
3421 }
3422 break;
3423 case FFS_OS_DESC_EXT_PROP: {
3424 struct usb_ext_prop_desc *desc = data;
3425 struct usb_os_desc_table *t;
3426 struct usb_os_desc_ext_prop *ext_prop;
3427 char *ext_prop_name;
3428 char *ext_prop_data;
3429
3430 t = &func->function.os_desc_table[h->interface];
3431 t->if_id = func->interfaces_nums[h->interface];
3432
3433 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
3434 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
3435
3436 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
3437 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
3438 ext_prop->data_len = le32_to_cpu(*(__le32 *)
3439 usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
3440 length = ext_prop->name_len + ext_prop->data_len + 14;
3441
3442 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
3443 func->ffs->ms_os_descs_ext_prop_name_avail +=
3444 ext_prop->name_len;
3445
3446 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
3447 func->ffs->ms_os_descs_ext_prop_data_avail +=
3448 ext_prop->data_len;
3449 memcpy(ext_prop_data,
3450 usb_ext_prop_data_ptr(data, ext_prop->name_len),
3451 ext_prop->data_len);
3452 /* unicode data reported to the host as "WCHAR"s */
3453 switch (ext_prop->type) {
3454 case USB_EXT_PROP_UNICODE:
3455 case USB_EXT_PROP_UNICODE_ENV:
3456 case USB_EXT_PROP_UNICODE_LINK:
3457 case USB_EXT_PROP_UNICODE_MULTI:
3458 ext_prop->data_len *= 2;
3459 break;
3460 }
3461 ext_prop->data = ext_prop_data;
3462
3463 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3464 ext_prop->name_len);
3465 /* property name reported to the host as "WCHAR"s */
3466 ext_prop->name_len *= 2;
3467 ext_prop->name = ext_prop_name;
3468
3469 t->os_desc->ext_prop_len +=
3470 ext_prop->name_len + ext_prop->data_len + 14;
3471 ++t->os_desc->ext_prop_count;
3472 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3473 }
3474 break;
3475 default:
3476 pr_vdebug("unknown descriptor: %d\n", type);
3477 }
3478
3479 return length;
3480 }
3481
ffs_do_functionfs_bind(struct usb_function * f,struct usb_configuration * c)3482 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3483 struct usb_configuration *c)
3484 {
3485 struct ffs_function *func = ffs_func_from_usb(f);
3486 struct f_fs_opts *ffs_opts =
3487 container_of(f->fi, struct f_fs_opts, func_inst);
3488 struct ffs_data *ffs_data;
3489 int ret;
3490
3491 /*
3492 * Legacy gadget triggers binding in functionfs_ready_callback,
3493 * which already uses locking; taking the same lock here would
3494 * cause a deadlock.
3495 *
3496 * Configfs-enabled gadgets however do need ffs_dev_lock.
3497 */
3498 if (!ffs_opts->no_configfs)
3499 ffs_dev_lock();
3500 ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3501 ffs_data = ffs_opts->dev->ffs_data;
3502 if (!ffs_opts->no_configfs)
3503 ffs_dev_unlock();
3504 if (ret)
3505 return ERR_PTR(ret);
3506
3507 func->ffs = ffs_data;
3508 func->conf = c;
3509 func->gadget = c->cdev->gadget;
3510
3511 /*
3512 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3513 * configurations are bound in sequence with list_for_each_entry,
3514 * in each configuration its functions are bound in sequence
3515 * with list_for_each_entry, so we assume no race condition
3516 * with regard to ffs_opts->bound access
3517 */
3518 if (!ffs_opts->refcnt) {
3519 ret = functionfs_bind(func->ffs, c->cdev);
3520 if (ret)
3521 return ERR_PTR(ret);
3522 }
3523 ffs_opts->refcnt++;
3524 func->function.strings = func->ffs->stringtabs;
3525
3526 return ffs_opts;
3527 }
3528
_ffs_func_bind(struct usb_configuration * c,struct usb_function * f)3529 static int _ffs_func_bind(struct usb_configuration *c,
3530 struct usb_function *f)
3531 {
3532 struct ffs_function *func = ffs_func_from_usb(f);
3533 struct ffs_data *ffs = func->ffs;
3534
3535 const int full = !!func->ffs->fs_descs_count;
3536 const int high = !!func->ffs->hs_descs_count;
3537 const int super = !!func->ffs->ss_descs_count;
3538
3539 int fs_len, hs_len, ss_len, ret, i;
3540 struct ffs_ep *eps_ptr;
3541
3542 /* Make it a single chunk, less management later on */
3543 vla_group(d);
3544 vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3545 vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3546 full ? ffs->fs_descs_count + 1 : 0);
3547 vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3548 high ? ffs->hs_descs_count + 1 : 0);
3549 vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3550 super ? ffs->ss_descs_count + 1 : 0);
3551 vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3552 vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3553 c->cdev->use_os_string ? ffs->interfaces_count : 0);
3554 vla_item_with_sz(d, char[16], ext_compat,
3555 c->cdev->use_os_string ? ffs->interfaces_count : 0);
3556 vla_item_with_sz(d, struct usb_os_desc, os_desc,
3557 c->cdev->use_os_string ? ffs->interfaces_count : 0);
3558 vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3559 ffs->ms_os_descs_ext_prop_count);
3560 vla_item_with_sz(d, char, ext_prop_name,
3561 ffs->ms_os_descs_ext_prop_name_len);
3562 vla_item_with_sz(d, char, ext_prop_data,
3563 ffs->ms_os_descs_ext_prop_data_len);
3564 vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3565 char *vlabuf;
3566
3567 /* Has descriptors only for speeds gadget does not support */
3568 if (!(full | high | super))
3569 return -ENOTSUPP;
3570
3571 /* Allocate a single chunk, less management later on */
3572 vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3573 if (!vlabuf)
3574 return -ENOMEM;
3575
3576 ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3577 ffs->ms_os_descs_ext_prop_name_avail =
3578 vla_ptr(vlabuf, d, ext_prop_name);
3579 ffs->ms_os_descs_ext_prop_data_avail =
3580 vla_ptr(vlabuf, d, ext_prop_data);
3581
3582 /* Copy descriptors */
3583 memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3584 ffs->raw_descs_length);
3585
3586 memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3587 eps_ptr = vla_ptr(vlabuf, d, eps);
3588 for (i = 0; i < ffs->eps_count; i++)
3589 eps_ptr[i].num = -1;
3590
3591 /* Save pointers
3592 * d_eps == vlabuf, func->eps used to kfree vlabuf later
3593 */
3594 func->eps = vla_ptr(vlabuf, d, eps);
3595 func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3596
3597 /*
3598 * Go through all the endpoint descriptors and allocate
3599 * endpoints first, so that later we can rewrite the endpoint
3600 * numbers without worrying that it may be described later on.
3601 */
3602 if (full) {
3603 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3604 fs_len = ffs_do_descs(ffs->fs_descs_count,
3605 vla_ptr(vlabuf, d, raw_descs),
3606 d_raw_descs__sz,
3607 __ffs_func_bind_do_descs, func);
3608 if (fs_len < 0) {
3609 ret = fs_len;
3610 goto error;
3611 }
3612 } else {
3613 fs_len = 0;
3614 }
3615
3616 if (high) {
3617 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3618 hs_len = ffs_do_descs(ffs->hs_descs_count,
3619 vla_ptr(vlabuf, d, raw_descs) + fs_len,
3620 d_raw_descs__sz - fs_len,
3621 __ffs_func_bind_do_descs, func);
3622 if (hs_len < 0) {
3623 ret = hs_len;
3624 goto error;
3625 }
3626 } else {
3627 hs_len = 0;
3628 }
3629
3630 if (super) {
3631 func->function.ss_descriptors = func->function.ssp_descriptors =
3632 vla_ptr(vlabuf, d, ss_descs);
3633 ss_len = ffs_do_descs(ffs->ss_descs_count,
3634 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3635 d_raw_descs__sz - fs_len - hs_len,
3636 __ffs_func_bind_do_descs, func);
3637 if (ss_len < 0) {
3638 ret = ss_len;
3639 goto error;
3640 }
3641 } else {
3642 ss_len = 0;
3643 }
3644
3645 /*
3646 * Now handle interface numbers allocation and interface and
3647 * endpoint numbers rewriting. We can do that in one go
3648 * now.
3649 */
3650 ret = ffs_do_descs(ffs->fs_descs_count +
3651 (high ? ffs->hs_descs_count : 0) +
3652 (super ? ffs->ss_descs_count : 0),
3653 vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3654 __ffs_func_bind_do_nums, func);
3655 if (ret < 0)
3656 goto error;
3657
3658 func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3659 if (c->cdev->use_os_string) {
3660 for (i = 0; i < ffs->interfaces_count; ++i) {
3661 struct usb_os_desc *desc;
3662
3663 desc = func->function.os_desc_table[i].os_desc =
3664 vla_ptr(vlabuf, d, os_desc) +
3665 i * sizeof(struct usb_os_desc);
3666 desc->ext_compat_id =
3667 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3668 INIT_LIST_HEAD(&desc->ext_prop);
3669 }
3670 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3671 vla_ptr(vlabuf, d, raw_descs) +
3672 fs_len + hs_len + ss_len,
3673 d_raw_descs__sz - fs_len - hs_len -
3674 ss_len,
3675 __ffs_func_bind_do_os_desc, func);
3676 if (ret < 0)
3677 goto error;
3678 }
3679 func->function.os_desc_n =
3680 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3681
3682 /* And we're done */
3683 ffs_event_add(ffs, FUNCTIONFS_BIND);
3684 return 0;
3685
3686 error:
3687 /* XXX Do we need to release all claimed endpoints here? */
3688 return ret;
3689 }
3690
ffs_func_bind(struct usb_configuration * c,struct usb_function * f)3691 static int ffs_func_bind(struct usb_configuration *c,
3692 struct usb_function *f)
3693 {
3694 struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3695 struct ffs_function *func = ffs_func_from_usb(f);
3696 int ret;
3697
3698 if (IS_ERR(ffs_opts))
3699 return PTR_ERR(ffs_opts);
3700
3701 ret = _ffs_func_bind(c, f);
3702 if (ret && !--ffs_opts->refcnt)
3703 functionfs_unbind(func->ffs);
3704
3705 return ret;
3706 }
3707
3708
3709 /* Other USB function hooks *************************************************/
3710
ffs_reset_work(struct work_struct * work)3711 static void ffs_reset_work(struct work_struct *work)
3712 {
3713 struct ffs_data *ffs = container_of(work,
3714 struct ffs_data, reset_work);
3715 ffs_data_reset(ffs);
3716 }
3717
ffs_func_get_alt(struct usb_function * f,unsigned int interface)3718 static int ffs_func_get_alt(struct usb_function *f,
3719 unsigned int interface)
3720 {
3721 struct ffs_function *func = ffs_func_from_usb(f);
3722 int intf = ffs_func_revmap_intf(func, interface);
3723
3724 return (intf < 0) ? intf : func->cur_alt[interface];
3725 }
3726
ffs_func_set_alt(struct usb_function * f,unsigned interface,unsigned alt)3727 static int ffs_func_set_alt(struct usb_function *f,
3728 unsigned interface, unsigned alt)
3729 {
3730 struct ffs_function *func = ffs_func_from_usb(f);
3731 struct ffs_data *ffs = func->ffs;
3732 int ret = 0, intf;
3733
3734 if (alt > MAX_ALT_SETTINGS)
3735 return -EINVAL;
3736
3737 intf = ffs_func_revmap_intf(func, interface);
3738 if (intf < 0)
3739 return intf;
3740
3741 if (ffs->func)
3742 ffs_func_eps_disable(ffs->func);
3743
3744 if (ffs->state == FFS_DEACTIVATED) {
3745 ffs->state = FFS_CLOSING;
3746 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3747 schedule_work(&ffs->reset_work);
3748 return -ENODEV;
3749 }
3750
3751 if (ffs->state != FFS_ACTIVE)
3752 return -ENODEV;
3753
3754 ffs->func = func;
3755 ret = ffs_func_eps_enable(func);
3756 if (ret >= 0) {
3757 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3758 func->cur_alt[interface] = alt;
3759 }
3760 return ret;
3761 }
3762
ffs_func_disable(struct usb_function * f)3763 static void ffs_func_disable(struct usb_function *f)
3764 {
3765 struct ffs_function *func = ffs_func_from_usb(f);
3766 struct ffs_data *ffs = func->ffs;
3767
3768 if (ffs->func)
3769 ffs_func_eps_disable(ffs->func);
3770
3771 if (ffs->state == FFS_DEACTIVATED) {
3772 ffs->state = FFS_CLOSING;
3773 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3774 schedule_work(&ffs->reset_work);
3775 return;
3776 }
3777
3778 if (ffs->state == FFS_ACTIVE) {
3779 ffs->func = NULL;
3780 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3781 }
3782 }
3783
ffs_func_setup(struct usb_function * f,const struct usb_ctrlrequest * creq)3784 static int ffs_func_setup(struct usb_function *f,
3785 const struct usb_ctrlrequest *creq)
3786 {
3787 struct ffs_function *func = ffs_func_from_usb(f);
3788 struct ffs_data *ffs = func->ffs;
3789 unsigned long flags;
3790 int ret;
3791
3792 pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3793 pr_vdebug("creq->bRequest = %02x\n", creq->bRequest);
3794 pr_vdebug("creq->wValue = %04x\n", le16_to_cpu(creq->wValue));
3795 pr_vdebug("creq->wIndex = %04x\n", le16_to_cpu(creq->wIndex));
3796 pr_vdebug("creq->wLength = %04x\n", le16_to_cpu(creq->wLength));
3797
3798 /*
3799 * Most requests directed to interface go through here
3800 * (notable exceptions are set/get interface) so we need to
3801 * handle them. All other either handled by composite or
3802 * passed to usb_configuration->setup() (if one is set). No
3803 * matter, we will handle requests directed to endpoint here
3804 * as well (as it's straightforward). Other request recipient
3805 * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3806 * is being used.
3807 */
3808 if (ffs->state != FFS_ACTIVE)
3809 return -ENODEV;
3810
3811 switch (creq->bRequestType & USB_RECIP_MASK) {
3812 case USB_RECIP_INTERFACE:
3813 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3814 if (ret < 0)
3815 return ret;
3816 break;
3817
3818 case USB_RECIP_ENDPOINT:
3819 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3820 if (ret < 0)
3821 return ret;
3822 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3823 ret = func->ffs->eps_addrmap[ret];
3824 break;
3825
3826 default:
3827 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3828 ret = le16_to_cpu(creq->wIndex);
3829 else
3830 return -EOPNOTSUPP;
3831 }
3832
3833 spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3834 ffs->ev.setup = *creq;
3835 ffs->ev.setup.wIndex = cpu_to_le16(ret);
3836 __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3837 spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3838
3839 return ffs->ev.setup.wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3840 }
3841
ffs_func_req_match(struct usb_function * f,const struct usb_ctrlrequest * creq,bool config0)3842 static bool ffs_func_req_match(struct usb_function *f,
3843 const struct usb_ctrlrequest *creq,
3844 bool config0)
3845 {
3846 struct ffs_function *func = ffs_func_from_usb(f);
3847
3848 if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3849 return false;
3850
3851 switch (creq->bRequestType & USB_RECIP_MASK) {
3852 case USB_RECIP_INTERFACE:
3853 return (ffs_func_revmap_intf(func,
3854 le16_to_cpu(creq->wIndex)) >= 0);
3855 case USB_RECIP_ENDPOINT:
3856 return (ffs_func_revmap_ep(func,
3857 le16_to_cpu(creq->wIndex)) >= 0);
3858 default:
3859 return (bool) (func->ffs->user_flags &
3860 FUNCTIONFS_ALL_CTRL_RECIP);
3861 }
3862 }
3863
ffs_func_suspend(struct usb_function * f)3864 static void ffs_func_suspend(struct usb_function *f)
3865 {
3866 ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3867 }
3868
ffs_func_resume(struct usb_function * f)3869 static void ffs_func_resume(struct usb_function *f)
3870 {
3871 ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3872 }
3873
3874
3875 /* Endpoint and interface numbers reverse mapping ***************************/
3876
ffs_func_revmap_ep(struct ffs_function * func,u8 num)3877 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3878 {
3879 num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3880 return num ? num : -EDOM;
3881 }
3882
ffs_func_revmap_intf(struct ffs_function * func,u8 intf)3883 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3884 {
3885 short *nums = func->interfaces_nums;
3886 unsigned count = func->ffs->interfaces_count;
3887
3888 for (; count; --count, ++nums) {
3889 if (*nums >= 0 && *nums == intf)
3890 return nums - func->interfaces_nums;
3891 }
3892
3893 return -EDOM;
3894 }
3895
3896
3897 /* Devices management *******************************************************/
3898
3899 static LIST_HEAD(ffs_devices);
3900
_ffs_do_find_dev(const char * name)3901 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3902 {
3903 struct ffs_dev *dev;
3904
3905 if (!name)
3906 return NULL;
3907
3908 list_for_each_entry(dev, &ffs_devices, entry) {
3909 if (strcmp(dev->name, name) == 0)
3910 return dev;
3911 }
3912
3913 return NULL;
3914 }
3915
3916 /*
3917 * ffs_lock must be taken by the caller of this function
3918 */
_ffs_get_single_dev(void)3919 static struct ffs_dev *_ffs_get_single_dev(void)
3920 {
3921 struct ffs_dev *dev;
3922
3923 if (list_is_singular(&ffs_devices)) {
3924 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3925 if (dev->single)
3926 return dev;
3927 }
3928
3929 return NULL;
3930 }
3931
3932 /*
3933 * ffs_lock must be taken by the caller of this function
3934 */
_ffs_find_dev(const char * name)3935 static struct ffs_dev *_ffs_find_dev(const char *name)
3936 {
3937 struct ffs_dev *dev;
3938
3939 dev = _ffs_get_single_dev();
3940 if (dev)
3941 return dev;
3942
3943 return _ffs_do_find_dev(name);
3944 }
3945
3946 /* Configfs support *********************************************************/
3947
to_ffs_opts(struct config_item * item)3948 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3949 {
3950 return container_of(to_config_group(item), struct f_fs_opts,
3951 func_inst.group);
3952 }
3953
f_fs_opts_ready_show(struct config_item * item,char * page)3954 static ssize_t f_fs_opts_ready_show(struct config_item *item, char *page)
3955 {
3956 struct f_fs_opts *opts = to_ffs_opts(item);
3957 int ready;
3958
3959 ffs_dev_lock();
3960 ready = opts->dev->desc_ready;
3961 ffs_dev_unlock();
3962
3963 return sprintf(page, "%d\n", ready);
3964 }
3965
3966 CONFIGFS_ATTR_RO(f_fs_opts_, ready);
3967
3968 static struct configfs_attribute *ffs_attrs[] = {
3969 &f_fs_opts_attr_ready,
3970 NULL,
3971 };
3972
ffs_attr_release(struct config_item * item)3973 static void ffs_attr_release(struct config_item *item)
3974 {
3975 struct f_fs_opts *opts = to_ffs_opts(item);
3976
3977 usb_put_function_instance(&opts->func_inst);
3978 }
3979
3980 static struct configfs_item_operations ffs_item_ops = {
3981 .release = ffs_attr_release,
3982 };
3983
3984 static const struct config_item_type ffs_func_type = {
3985 .ct_item_ops = &ffs_item_ops,
3986 .ct_attrs = ffs_attrs,
3987 .ct_owner = THIS_MODULE,
3988 };
3989
3990
3991 /* Function registration interface ******************************************/
3992
ffs_free_inst(struct usb_function_instance * f)3993 static void ffs_free_inst(struct usb_function_instance *f)
3994 {
3995 struct f_fs_opts *opts;
3996
3997 opts = to_f_fs_opts(f);
3998 ffs_release_dev(opts->dev);
3999 ffs_dev_lock();
4000 _ffs_free_dev(opts->dev);
4001 ffs_dev_unlock();
4002 kfree(opts);
4003 }
4004
ffs_set_inst_name(struct usb_function_instance * fi,const char * name)4005 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
4006 {
4007 if (strlen(name) >= sizeof_field(struct ffs_dev, name))
4008 return -ENAMETOOLONG;
4009 return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
4010 }
4011
ffs_alloc_inst(void)4012 static struct usb_function_instance *ffs_alloc_inst(void)
4013 {
4014 struct f_fs_opts *opts;
4015 struct ffs_dev *dev;
4016
4017 opts = kzalloc(sizeof(*opts), GFP_KERNEL);
4018 if (!opts)
4019 return ERR_PTR(-ENOMEM);
4020
4021 opts->func_inst.set_inst_name = ffs_set_inst_name;
4022 opts->func_inst.free_func_inst = ffs_free_inst;
4023 ffs_dev_lock();
4024 dev = _ffs_alloc_dev();
4025 ffs_dev_unlock();
4026 if (IS_ERR(dev)) {
4027 kfree(opts);
4028 return ERR_CAST(dev);
4029 }
4030 opts->dev = dev;
4031 dev->opts = opts;
4032
4033 config_group_init_type_name(&opts->func_inst.group, "",
4034 &ffs_func_type);
4035 return &opts->func_inst;
4036 }
4037
ffs_free(struct usb_function * f)4038 static void ffs_free(struct usb_function *f)
4039 {
4040 kfree(ffs_func_from_usb(f));
4041 }
4042
ffs_func_unbind(struct usb_configuration * c,struct usb_function * f)4043 static void ffs_func_unbind(struct usb_configuration *c,
4044 struct usb_function *f)
4045 {
4046 struct ffs_function *func = ffs_func_from_usb(f);
4047 struct ffs_data *ffs = func->ffs;
4048 struct f_fs_opts *opts =
4049 container_of(f->fi, struct f_fs_opts, func_inst);
4050 struct ffs_ep *ep = func->eps;
4051 unsigned count = ffs->eps_count;
4052 unsigned long flags;
4053
4054 if (ffs->func == func) {
4055 ffs_func_eps_disable(func);
4056 ffs->func = NULL;
4057 }
4058
4059 /* Drain any pending AIO completions */
4060 drain_workqueue(ffs->io_completion_wq);
4061
4062 ffs_event_add(ffs, FUNCTIONFS_UNBIND);
4063 if (!--opts->refcnt)
4064 functionfs_unbind(ffs);
4065
4066 /* cleanup after autoconfig */
4067 spin_lock_irqsave(&func->ffs->eps_lock, flags);
4068 while (count--) {
4069 if (ep->ep && ep->req)
4070 usb_ep_free_request(ep->ep, ep->req);
4071 ep->req = NULL;
4072 ++ep;
4073 }
4074 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
4075 kfree(func->eps);
4076 func->eps = NULL;
4077 /*
4078 * eps, descriptors and interfaces_nums are allocated in the
4079 * same chunk so only one free is required.
4080 */
4081 func->function.fs_descriptors = NULL;
4082 func->function.hs_descriptors = NULL;
4083 func->function.ss_descriptors = NULL;
4084 func->function.ssp_descriptors = NULL;
4085 func->interfaces_nums = NULL;
4086
4087 }
4088
ffs_alloc(struct usb_function_instance * fi)4089 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
4090 {
4091 struct ffs_function *func;
4092
4093 func = kzalloc(sizeof(*func), GFP_KERNEL);
4094 if (!func)
4095 return ERR_PTR(-ENOMEM);
4096
4097 func->function.name = "Function FS Gadget";
4098
4099 func->function.bind = ffs_func_bind;
4100 func->function.unbind = ffs_func_unbind;
4101 func->function.set_alt = ffs_func_set_alt;
4102 func->function.get_alt = ffs_func_get_alt;
4103 func->function.disable = ffs_func_disable;
4104 func->function.setup = ffs_func_setup;
4105 func->function.req_match = ffs_func_req_match;
4106 func->function.suspend = ffs_func_suspend;
4107 func->function.resume = ffs_func_resume;
4108 func->function.free_func = ffs_free;
4109
4110 return &func->function;
4111 }
4112
4113 /*
4114 * ffs_lock must be taken by the caller of this function
4115 */
_ffs_alloc_dev(void)4116 static struct ffs_dev *_ffs_alloc_dev(void)
4117 {
4118 struct ffs_dev *dev;
4119 int ret;
4120
4121 if (_ffs_get_single_dev())
4122 return ERR_PTR(-EBUSY);
4123
4124 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4125 if (!dev)
4126 return ERR_PTR(-ENOMEM);
4127
4128 if (list_empty(&ffs_devices)) {
4129 ret = functionfs_init();
4130 if (ret) {
4131 kfree(dev);
4132 return ERR_PTR(ret);
4133 }
4134 }
4135
4136 list_add(&dev->entry, &ffs_devices);
4137
4138 return dev;
4139 }
4140
ffs_name_dev(struct ffs_dev * dev,const char * name)4141 int ffs_name_dev(struct ffs_dev *dev, const char *name)
4142 {
4143 struct ffs_dev *existing;
4144 int ret = 0;
4145
4146 ffs_dev_lock();
4147
4148 existing = _ffs_do_find_dev(name);
4149 if (!existing)
4150 strscpy(dev->name, name, ARRAY_SIZE(dev->name));
4151 else if (existing != dev)
4152 ret = -EBUSY;
4153
4154 ffs_dev_unlock();
4155
4156 return ret;
4157 }
4158 EXPORT_SYMBOL_GPL(ffs_name_dev);
4159
ffs_single_dev(struct ffs_dev * dev)4160 int ffs_single_dev(struct ffs_dev *dev)
4161 {
4162 int ret;
4163
4164 ret = 0;
4165 ffs_dev_lock();
4166
4167 if (!list_is_singular(&ffs_devices))
4168 ret = -EBUSY;
4169 else
4170 dev->single = true;
4171
4172 ffs_dev_unlock();
4173 return ret;
4174 }
4175 EXPORT_SYMBOL_GPL(ffs_single_dev);
4176
4177 /*
4178 * ffs_lock must be taken by the caller of this function
4179 */
_ffs_free_dev(struct ffs_dev * dev)4180 static void _ffs_free_dev(struct ffs_dev *dev)
4181 {
4182 list_del(&dev->entry);
4183
4184 kfree(dev);
4185 if (list_empty(&ffs_devices))
4186 functionfs_cleanup();
4187 }
4188
ffs_acquire_dev(const char * dev_name,struct ffs_data * ffs_data)4189 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data)
4190 {
4191 int ret = 0;
4192 struct ffs_dev *ffs_dev;
4193
4194 ffs_dev_lock();
4195
4196 ffs_dev = _ffs_find_dev(dev_name);
4197 if (!ffs_dev) {
4198 ret = -ENOENT;
4199 } else if (ffs_dev->mounted) {
4200 ret = -EBUSY;
4201 } else if (ffs_dev->ffs_acquire_dev_callback &&
4202 ffs_dev->ffs_acquire_dev_callback(ffs_dev)) {
4203 ret = -ENOENT;
4204 } else {
4205 ffs_dev->mounted = true;
4206 ffs_dev->ffs_data = ffs_data;
4207 ffs_data->private_data = ffs_dev;
4208 }
4209
4210 ffs_dev_unlock();
4211 return ret;
4212 }
4213
ffs_release_dev(struct ffs_dev * ffs_dev)4214 static void ffs_release_dev(struct ffs_dev *ffs_dev)
4215 {
4216 ffs_dev_lock();
4217
4218 if (ffs_dev && ffs_dev->mounted) {
4219 ffs_dev->mounted = false;
4220 if (ffs_dev->ffs_data) {
4221 ffs_dev->ffs_data->private_data = NULL;
4222 ffs_dev->ffs_data = NULL;
4223 }
4224
4225 if (ffs_dev->ffs_release_dev_callback)
4226 ffs_dev->ffs_release_dev_callback(ffs_dev);
4227 }
4228
4229 ffs_dev_unlock();
4230 }
4231
ffs_ready(struct ffs_data * ffs)4232 static int ffs_ready(struct ffs_data *ffs)
4233 {
4234 struct ffs_dev *ffs_obj;
4235 int ret = 0;
4236
4237 ffs_dev_lock();
4238
4239 ffs_obj = ffs->private_data;
4240 if (!ffs_obj) {
4241 ret = -EINVAL;
4242 goto done;
4243 }
4244 if (WARN_ON(ffs_obj->desc_ready)) {
4245 ret = -EBUSY;
4246 goto done;
4247 }
4248
4249 ffs_obj->desc_ready = true;
4250
4251 if (ffs_obj->ffs_ready_callback) {
4252 ret = ffs_obj->ffs_ready_callback(ffs);
4253 if (ret)
4254 goto done;
4255 }
4256
4257 set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
4258 done:
4259 ffs_dev_unlock();
4260 return ret;
4261 }
4262
ffs_closed(struct ffs_data * ffs)4263 static void ffs_closed(struct ffs_data *ffs)
4264 {
4265 struct ffs_dev *ffs_obj;
4266 struct f_fs_opts *opts;
4267 struct config_item *ci;
4268
4269 ffs_dev_lock();
4270
4271 ffs_obj = ffs->private_data;
4272 if (!ffs_obj)
4273 goto done;
4274
4275 ffs_obj->desc_ready = false;
4276
4277 if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
4278 ffs_obj->ffs_closed_callback)
4279 ffs_obj->ffs_closed_callback(ffs);
4280
4281 if (ffs_obj->opts)
4282 opts = ffs_obj->opts;
4283 else
4284 goto done;
4285
4286 if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
4287 || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
4288 goto done;
4289
4290 ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
4291 ffs_dev_unlock();
4292
4293 if (test_bit(FFS_FL_BOUND, &ffs->flags))
4294 unregister_gadget_item(ci);
4295 return;
4296 done:
4297 ffs_dev_unlock();
4298 }
4299
4300 /* Misc helper functions ****************************************************/
4301
ffs_mutex_lock(struct mutex * mutex,unsigned nonblock)4302 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
4303 {
4304 return nonblock
4305 ? mutex_trylock(mutex) ? 0 : -EAGAIN
4306 : mutex_lock_interruptible(mutex);
4307 }
4308
ffs_prepare_buffer(const char __user * buf,size_t len)4309 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
4310 {
4311 char *data;
4312
4313 if (!len)
4314 return NULL;
4315
4316 data = memdup_user(buf, len);
4317 if (IS_ERR(data))
4318 return data;
4319
4320 pr_vdebug("Buffer from user space:\n");
4321 ffs_dump_mem("", data, len);
4322
4323 return data;
4324 }
4325
4326 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
4327 MODULE_DESCRIPTION("user mode file system API for USB composite function controllers");
4328 MODULE_LICENSE("GPL");
4329 MODULE_AUTHOR("Michal Nazarewicz");
4330