Version:  2.0.40 2.2.26 2.4.37 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15

Linux/drivers/usb/gadget/f_fs.c

  1 /*
  2  * f_fs.c -- user mode file system API for USB composite function controllers
  3  *
  4  * Copyright (C) 2010 Samsung Electronics
  5  * Author: Michal Nazarewicz <mina86@mina86.com>
  6  *
  7  * Based on inode.c (GadgetFS) which was:
  8  * Copyright (C) 2003-2004 David Brownell
  9  * Copyright (C) 2003 Agilent Technologies
 10  *
 11  * This program is free software; you can redistribute it and/or modify
 12  * it under the terms of the GNU General Public License as published by
 13  * the Free Software Foundation; either version 2 of the License, or
 14  * (at your option) any later version.
 15  */
 16 
 17 
 18 /* #define DEBUG */
 19 /* #define VERBOSE_DEBUG */
 20 
 21 #include <linux/blkdev.h>
 22 #include <linux/pagemap.h>
 23 #include <linux/export.h>
 24 #include <linux/hid.h>
 25 #include <linux/module.h>
 26 #include <asm/unaligned.h>
 27 
 28 #include <linux/usb/composite.h>
 29 #include <linux/usb/functionfs.h>
 30 
 31 #include <linux/aio.h>
 32 #include <linux/mmu_context.h>
 33 #include <linux/poll.h>
 34 
 35 #include "u_fs.h"
 36 #include "configfs.h"
 37 
 38 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
 39 
 40 /* Variable Length Array Macros **********************************************/
 41 #define vla_group(groupname) size_t groupname##__next = 0
 42 #define vla_group_size(groupname) groupname##__next
 43 
 44 #define vla_item(groupname, type, name, n) \
 45         size_t groupname##_##name##__offset = ({                               \
 46                 size_t align_mask = __alignof__(type) - 1;                     \
 47                 size_t offset = (groupname##__next + align_mask) & ~align_mask;\
 48                 size_t size = (n) * sizeof(type);                              \
 49                 groupname##__next = offset + size;                             \
 50                 offset;                                                        \
 51         })
 52 
 53 #define vla_item_with_sz(groupname, type, name, n) \
 54         size_t groupname##_##name##__sz = (n) * sizeof(type);                  \
 55         size_t groupname##_##name##__offset = ({                               \
 56                 size_t align_mask = __alignof__(type) - 1;                     \
 57                 size_t offset = (groupname##__next + align_mask) & ~align_mask;\
 58                 size_t size = groupname##_##name##__sz;                        \
 59                 groupname##__next = offset + size;                             \
 60                 offset;                                                        \
 61         })
 62 
 63 #define vla_ptr(ptr, groupname, name) \
 64         ((void *) ((char *)ptr + groupname##_##name##__offset))
 65 
 66 /* Reference counter handling */
 67 static void ffs_data_get(struct ffs_data *ffs);
 68 static void ffs_data_put(struct ffs_data *ffs);
 69 /* Creates new ffs_data object. */
 70 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
 71 
 72 /* Opened counter handling. */
 73 static void ffs_data_opened(struct ffs_data *ffs);
 74 static void ffs_data_closed(struct ffs_data *ffs);
 75 
 76 /* Called with ffs->mutex held; take over ownership of data. */
 77 static int __must_check
 78 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
 79 static int __must_check
 80 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
 81 
 82 
 83 /* The function structure ***************************************************/
 84 
 85 struct ffs_ep;
 86 
 87 struct ffs_function {
 88         struct usb_configuration        *conf;
 89         struct usb_gadget               *gadget;
 90         struct ffs_data                 *ffs;
 91 
 92         struct ffs_ep                   *eps;
 93         u8                              eps_revmap[16];
 94         short                           *interfaces_nums;
 95 
 96         struct usb_function             function;
 97 };
 98 
 99 
100 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
101 {
102         return container_of(f, struct ffs_function, function);
103 }
104 
105 
106 static inline enum ffs_setup_state
107 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
108 {
109         return (enum ffs_setup_state)
110                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
111 }
112 
113 
114 static void ffs_func_eps_disable(struct ffs_function *func);
115 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
116 
117 static int ffs_func_bind(struct usb_configuration *,
118                          struct usb_function *);
119 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
120 static void ffs_func_disable(struct usb_function *);
121 static int ffs_func_setup(struct usb_function *,
122                           const struct usb_ctrlrequest *);
123 static void ffs_func_suspend(struct usb_function *);
124 static void ffs_func_resume(struct usb_function *);
125 
126 
127 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
128 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
129 
130 
131 /* The endpoints structures *************************************************/
132 
133 struct ffs_ep {
134         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
135         struct usb_request              *req;   /* P: epfile->mutex */
136 
137         /* [0]: full speed, [1]: high speed, [2]: super speed */
138         struct usb_endpoint_descriptor  *descs[3];
139 
140         u8                              num;
141 
142         int                             status; /* P: epfile->mutex */
143 };
144 
145 struct ffs_epfile {
146         /* Protects ep->ep and ep->req. */
147         struct mutex                    mutex;
148         wait_queue_head_t               wait;
149 
150         struct ffs_data                 *ffs;
151         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
152 
153         struct dentry                   *dentry;
154 
155         char                            name[5];
156 
157         unsigned char                   in;     /* P: ffs->eps_lock */
158         unsigned char                   isoc;   /* P: ffs->eps_lock */
159 
160         unsigned char                   _pad;
161 };
162 
163 /*  ffs_io_data structure ***************************************************/
164 
165 struct ffs_io_data {
166         bool aio;
167         bool read;
168 
169         struct kiocb *kiocb;
170         const struct iovec *iovec;
171         unsigned long nr_segs;
172         char __user *buf;
173         size_t len;
174 
175         struct mm_struct *mm;
176         struct work_struct work;
177 
178         struct usb_ep *ep;
179         struct usb_request *req;
180 };
181 
182 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
183 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
184 
185 static struct inode *__must_check
186 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
187                    const struct file_operations *fops,
188                    struct dentry **dentry_p);
189 
190 /* Devices management *******************************************************/
191 
192 DEFINE_MUTEX(ffs_lock);
193 EXPORT_SYMBOL(ffs_lock);
194 
195 static struct ffs_dev *_ffs_find_dev(const char *name);
196 static struct ffs_dev *_ffs_alloc_dev(void);
197 static int _ffs_name_dev(struct ffs_dev *dev, const char *name);
198 static void _ffs_free_dev(struct ffs_dev *dev);
199 static void *ffs_acquire_dev(const char *dev_name);
200 static void ffs_release_dev(struct ffs_data *ffs_data);
201 static int ffs_ready(struct ffs_data *ffs);
202 static void ffs_closed(struct ffs_data *ffs);
203 
204 /* Misc helper functions ****************************************************/
205 
206 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
207         __attribute__((warn_unused_result, nonnull));
208 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
209         __attribute__((warn_unused_result, nonnull));
210 
211 
212 /* Control file aka ep0 *****************************************************/
213 
214 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
215 {
216         struct ffs_data *ffs = req->context;
217 
218         complete_all(&ffs->ep0req_completion);
219 }
220 
221 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
222 {
223         struct usb_request *req = ffs->ep0req;
224         int ret;
225 
226         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
227 
228         spin_unlock_irq(&ffs->ev.waitq.lock);
229 
230         req->buf      = data;
231         req->length   = len;
232 
233         /*
234          * UDC layer requires to provide a buffer even for ZLP, but should
235          * not use it at all. Let's provide some poisoned pointer to catch
236          * possible bug in the driver.
237          */
238         if (req->buf == NULL)
239                 req->buf = (void *)0xDEADBABE;
240 
241         reinit_completion(&ffs->ep0req_completion);
242 
243         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
244         if (unlikely(ret < 0))
245                 return ret;
246 
247         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
248         if (unlikely(ret)) {
249                 usb_ep_dequeue(ffs->gadget->ep0, req);
250                 return -EINTR;
251         }
252 
253         ffs->setup_state = FFS_NO_SETUP;
254         return req->status ? req->status : req->actual;
255 }
256 
257 static int __ffs_ep0_stall(struct ffs_data *ffs)
258 {
259         if (ffs->ev.can_stall) {
260                 pr_vdebug("ep0 stall\n");
261                 usb_ep_set_halt(ffs->gadget->ep0);
262                 ffs->setup_state = FFS_NO_SETUP;
263                 return -EL2HLT;
264         } else {
265                 pr_debug("bogus ep0 stall!\n");
266                 return -ESRCH;
267         }
268 }
269 
270 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
271                              size_t len, loff_t *ptr)
272 {
273         struct ffs_data *ffs = file->private_data;
274         ssize_t ret;
275         char *data;
276 
277         ENTER();
278 
279         /* Fast check if setup was canceled */
280         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
281                 return -EIDRM;
282 
283         /* Acquire mutex */
284         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
285         if (unlikely(ret < 0))
286                 return ret;
287 
288         /* Check state */
289         switch (ffs->state) {
290         case FFS_READ_DESCRIPTORS:
291         case FFS_READ_STRINGS:
292                 /* Copy data */
293                 if (unlikely(len < 16)) {
294                         ret = -EINVAL;
295                         break;
296                 }
297 
298                 data = ffs_prepare_buffer(buf, len);
299                 if (IS_ERR(data)) {
300                         ret = PTR_ERR(data);
301                         break;
302                 }
303 
304                 /* Handle data */
305                 if (ffs->state == FFS_READ_DESCRIPTORS) {
306                         pr_info("read descriptors\n");
307                         ret = __ffs_data_got_descs(ffs, data, len);
308                         if (unlikely(ret < 0))
309                                 break;
310 
311                         ffs->state = FFS_READ_STRINGS;
312                         ret = len;
313                 } else {
314                         pr_info("read strings\n");
315                         ret = __ffs_data_got_strings(ffs, data, len);
316                         if (unlikely(ret < 0))
317                                 break;
318 
319                         ret = ffs_epfiles_create(ffs);
320                         if (unlikely(ret)) {
321                                 ffs->state = FFS_CLOSING;
322                                 break;
323                         }
324 
325                         ffs->state = FFS_ACTIVE;
326                         mutex_unlock(&ffs->mutex);
327 
328                         ret = ffs_ready(ffs);
329                         if (unlikely(ret < 0)) {
330                                 ffs->state = FFS_CLOSING;
331                                 return ret;
332                         }
333 
334                         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
335                         return len;
336                 }
337                 break;
338 
339         case FFS_ACTIVE:
340                 data = NULL;
341                 /*
342                  * We're called from user space, we can use _irq
343                  * rather then _irqsave
344                  */
345                 spin_lock_irq(&ffs->ev.waitq.lock);
346                 switch (ffs_setup_state_clear_cancelled(ffs)) {
347                 case FFS_SETUP_CANCELLED:
348                         ret = -EIDRM;
349                         goto done_spin;
350 
351                 case FFS_NO_SETUP:
352                         ret = -ESRCH;
353                         goto done_spin;
354 
355                 case FFS_SETUP_PENDING:
356                         break;
357                 }
358 
359                 /* FFS_SETUP_PENDING */
360                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
361                         spin_unlock_irq(&ffs->ev.waitq.lock);
362                         ret = __ffs_ep0_stall(ffs);
363                         break;
364                 }
365 
366                 /* FFS_SETUP_PENDING and not stall */
367                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
368 
369                 spin_unlock_irq(&ffs->ev.waitq.lock);
370 
371                 data = ffs_prepare_buffer(buf, len);
372                 if (IS_ERR(data)) {
373                         ret = PTR_ERR(data);
374                         break;
375                 }
376 
377                 spin_lock_irq(&ffs->ev.waitq.lock);
378 
379                 /*
380                  * We are guaranteed to be still in FFS_ACTIVE state
381                  * but the state of setup could have changed from
382                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
383                  * to check for that.  If that happened we copied data
384                  * from user space in vain but it's unlikely.
385                  *
386                  * For sure we are not in FFS_NO_SETUP since this is
387                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
388                  * transition can be performed and it's protected by
389                  * mutex.
390                  */
391                 if (ffs_setup_state_clear_cancelled(ffs) ==
392                     FFS_SETUP_CANCELLED) {
393                         ret = -EIDRM;
394 done_spin:
395                         spin_unlock_irq(&ffs->ev.waitq.lock);
396                 } else {
397                         /* unlocks spinlock */
398                         ret = __ffs_ep0_queue_wait(ffs, data, len);
399                 }
400                 kfree(data);
401                 break;
402 
403         default:
404                 ret = -EBADFD;
405                 break;
406         }
407 
408         mutex_unlock(&ffs->mutex);
409         return ret;
410 }
411 
412 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
413                                      size_t n)
414 {
415         /*
416          * We are holding ffs->ev.waitq.lock and ffs->mutex and we need
417          * to release them.
418          */
419         struct usb_functionfs_event events[n];
420         unsigned i = 0;
421 
422         memset(events, 0, sizeof events);
423 
424         do {
425                 events[i].type = ffs->ev.types[i];
426                 if (events[i].type == FUNCTIONFS_SETUP) {
427                         events[i].u.setup = ffs->ev.setup;
428                         ffs->setup_state = FFS_SETUP_PENDING;
429                 }
430         } while (++i < n);
431 
432         if (n < ffs->ev.count) {
433                 ffs->ev.count -= n;
434                 memmove(ffs->ev.types, ffs->ev.types + n,
435                         ffs->ev.count * sizeof *ffs->ev.types);
436         } else {
437                 ffs->ev.count = 0;
438         }
439 
440         spin_unlock_irq(&ffs->ev.waitq.lock);
441         mutex_unlock(&ffs->mutex);
442 
443         return unlikely(__copy_to_user(buf, events, sizeof events))
444                 ? -EFAULT : sizeof events;
445 }
446 
447 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
448                             size_t len, loff_t *ptr)
449 {
450         struct ffs_data *ffs = file->private_data;
451         char *data = NULL;
452         size_t n;
453         int ret;
454 
455         ENTER();
456 
457         /* Fast check if setup was canceled */
458         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
459                 return -EIDRM;
460 
461         /* Acquire mutex */
462         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
463         if (unlikely(ret < 0))
464                 return ret;
465 
466         /* Check state */
467         if (ffs->state != FFS_ACTIVE) {
468                 ret = -EBADFD;
469                 goto done_mutex;
470         }
471 
472         /*
473          * We're called from user space, we can use _irq rather then
474          * _irqsave
475          */
476         spin_lock_irq(&ffs->ev.waitq.lock);
477 
478         switch (ffs_setup_state_clear_cancelled(ffs)) {
479         case FFS_SETUP_CANCELLED:
480                 ret = -EIDRM;
481                 break;
482 
483         case FFS_NO_SETUP:
484                 n = len / sizeof(struct usb_functionfs_event);
485                 if (unlikely(!n)) {
486                         ret = -EINVAL;
487                         break;
488                 }
489 
490                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
491                         ret = -EAGAIN;
492                         break;
493                 }
494 
495                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
496                                                         ffs->ev.count)) {
497                         ret = -EINTR;
498                         break;
499                 }
500 
501                 return __ffs_ep0_read_events(ffs, buf,
502                                              min(n, (size_t)ffs->ev.count));
503 
504         case FFS_SETUP_PENDING:
505                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
506                         spin_unlock_irq(&ffs->ev.waitq.lock);
507                         ret = __ffs_ep0_stall(ffs);
508                         goto done_mutex;
509                 }
510 
511                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
512 
513                 spin_unlock_irq(&ffs->ev.waitq.lock);
514 
515                 if (likely(len)) {
516                         data = kmalloc(len, GFP_KERNEL);
517                         if (unlikely(!data)) {
518                                 ret = -ENOMEM;
519                                 goto done_mutex;
520                         }
521                 }
522 
523                 spin_lock_irq(&ffs->ev.waitq.lock);
524 
525                 /* See ffs_ep0_write() */
526                 if (ffs_setup_state_clear_cancelled(ffs) ==
527                     FFS_SETUP_CANCELLED) {
528                         ret = -EIDRM;
529                         break;
530                 }
531 
532                 /* unlocks spinlock */
533                 ret = __ffs_ep0_queue_wait(ffs, data, len);
534                 if (likely(ret > 0) && unlikely(__copy_to_user(buf, data, len)))
535                         ret = -EFAULT;
536                 goto done_mutex;
537 
538         default:
539                 ret = -EBADFD;
540                 break;
541         }
542 
543         spin_unlock_irq(&ffs->ev.waitq.lock);
544 done_mutex:
545         mutex_unlock(&ffs->mutex);
546         kfree(data);
547         return ret;
548 }
549 
550 static int ffs_ep0_open(struct inode *inode, struct file *file)
551 {
552         struct ffs_data *ffs = inode->i_private;
553 
554         ENTER();
555 
556         if (unlikely(ffs->state == FFS_CLOSING))
557                 return -EBUSY;
558 
559         file->private_data = ffs;
560         ffs_data_opened(ffs);
561 
562         return 0;
563 }
564 
565 static int ffs_ep0_release(struct inode *inode, struct file *file)
566 {
567         struct ffs_data *ffs = file->private_data;
568 
569         ENTER();
570 
571         ffs_data_closed(ffs);
572 
573         return 0;
574 }
575 
576 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
577 {
578         struct ffs_data *ffs = file->private_data;
579         struct usb_gadget *gadget = ffs->gadget;
580         long ret;
581 
582         ENTER();
583 
584         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
585                 struct ffs_function *func = ffs->func;
586                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
587         } else if (gadget && gadget->ops->ioctl) {
588                 ret = gadget->ops->ioctl(gadget, code, value);
589         } else {
590                 ret = -ENOTTY;
591         }
592 
593         return ret;
594 }
595 
596 static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
597 {
598         struct ffs_data *ffs = file->private_data;
599         unsigned int mask = POLLWRNORM;
600         int ret;
601 
602         poll_wait(file, &ffs->ev.waitq, wait);
603 
604         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
605         if (unlikely(ret < 0))
606                 return mask;
607 
608         switch (ffs->state) {
609         case FFS_READ_DESCRIPTORS:
610         case FFS_READ_STRINGS:
611                 mask |= POLLOUT;
612                 break;
613 
614         case FFS_ACTIVE:
615                 switch (ffs->setup_state) {
616                 case FFS_NO_SETUP:
617                         if (ffs->ev.count)
618                                 mask |= POLLIN;
619                         break;
620 
621                 case FFS_SETUP_PENDING:
622                 case FFS_SETUP_CANCELLED:
623                         mask |= (POLLIN | POLLOUT);
624                         break;
625                 }
626         case FFS_CLOSING:
627                 break;
628         }
629 
630         mutex_unlock(&ffs->mutex);
631 
632         return mask;
633 }
634 
635 static const struct file_operations ffs_ep0_operations = {
636         .llseek =       no_llseek,
637 
638         .open =         ffs_ep0_open,
639         .write =        ffs_ep0_write,
640         .read =         ffs_ep0_read,
641         .release =      ffs_ep0_release,
642         .unlocked_ioctl =       ffs_ep0_ioctl,
643         .poll =         ffs_ep0_poll,
644 };
645 
646 
647 /* "Normal" endpoints operations ********************************************/
648 
649 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
650 {
651         ENTER();
652         if (likely(req->context)) {
653                 struct ffs_ep *ep = _ep->driver_data;
654                 ep->status = req->status ? req->status : req->actual;
655                 complete(req->context);
656         }
657 }
658 
659 static void ffs_user_copy_worker(struct work_struct *work)
660 {
661         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
662                                                    work);
663         int ret = io_data->req->status ? io_data->req->status :
664                                          io_data->req->actual;
665 
666         if (io_data->read && ret > 0) {
667                 int i;
668                 size_t pos = 0;
669                 use_mm(io_data->mm);
670                 for (i = 0; i < io_data->nr_segs; i++) {
671                         if (unlikely(copy_to_user(io_data->iovec[i].iov_base,
672                                                  &io_data->buf[pos],
673                                                  io_data->iovec[i].iov_len))) {
674                                 ret = -EFAULT;
675                                 break;
676                         }
677                         pos += io_data->iovec[i].iov_len;
678                 }
679                 unuse_mm(io_data->mm);
680         }
681 
682         aio_complete(io_data->kiocb, ret, ret);
683 
684         usb_ep_free_request(io_data->ep, io_data->req);
685 
686         io_data->kiocb->private = NULL;
687         if (io_data->read)
688                 kfree(io_data->iovec);
689         kfree(io_data->buf);
690         kfree(io_data);
691 }
692 
693 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
694                                          struct usb_request *req)
695 {
696         struct ffs_io_data *io_data = req->context;
697 
698         ENTER();
699 
700         INIT_WORK(&io_data->work, ffs_user_copy_worker);
701         schedule_work(&io_data->work);
702 }
703 
704 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
705 {
706         struct ffs_epfile *epfile = file->private_data;
707         struct ffs_ep *ep;
708         char *data = NULL;
709         ssize_t ret, data_len;
710         int halt;
711 
712         /* Are we still active? */
713         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
714                 ret = -ENODEV;
715                 goto error;
716         }
717 
718         /* Wait for endpoint to be enabled */
719         ep = epfile->ep;
720         if (!ep) {
721                 if (file->f_flags & O_NONBLOCK) {
722                         ret = -EAGAIN;
723                         goto error;
724                 }
725 
726                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
727                 if (ret) {
728                         ret = -EINTR;
729                         goto error;
730                 }
731         }
732 
733         /* Do we halt? */
734         halt = (!io_data->read == !epfile->in);
735         if (halt && epfile->isoc) {
736                 ret = -EINVAL;
737                 goto error;
738         }
739 
740         /* Allocate & copy */
741         if (!halt) {
742                 /*
743                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
744                  * before the waiting completes, so do not assign to 'gadget' earlier
745                  */
746                 struct usb_gadget *gadget = epfile->ffs->gadget;
747 
748                 spin_lock_irq(&epfile->ffs->eps_lock);
749                 /* In the meantime, endpoint got disabled or changed. */
750                 if (epfile->ep != ep) {
751                         spin_unlock_irq(&epfile->ffs->eps_lock);
752                         return -ESHUTDOWN;
753                 }
754                 /*
755                  * Controller may require buffer size to be aligned to
756                  * maxpacketsize of an out endpoint.
757                  */
758                 data_len = io_data->read ?
759                            usb_ep_align_maybe(gadget, ep->ep, io_data->len) :
760                            io_data->len;
761                 spin_unlock_irq(&epfile->ffs->eps_lock);
762 
763                 data = kmalloc(data_len, GFP_KERNEL);
764                 if (unlikely(!data))
765                         return -ENOMEM;
766                 if (io_data->aio && !io_data->read) {
767                         int i;
768                         size_t pos = 0;
769                         for (i = 0; i < io_data->nr_segs; i++) {
770                                 if (unlikely(copy_from_user(&data[pos],
771                                              io_data->iovec[i].iov_base,
772                                              io_data->iovec[i].iov_len))) {
773                                         ret = -EFAULT;
774                                         goto error;
775                                 }
776                                 pos += io_data->iovec[i].iov_len;
777                         }
778                 } else {
779                         if (!io_data->read &&
780                             unlikely(__copy_from_user(data, io_data->buf,
781                                                       io_data->len))) {
782                                 ret = -EFAULT;
783                                 goto error;
784                         }
785                 }
786         }
787 
788         /* We will be using request */
789         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
790         if (unlikely(ret))
791                 goto error;
792 
793         spin_lock_irq(&epfile->ffs->eps_lock);
794 
795         if (epfile->ep != ep) {
796                 /* In the meantime, endpoint got disabled or changed. */
797                 ret = -ESHUTDOWN;
798                 spin_unlock_irq(&epfile->ffs->eps_lock);
799         } else if (halt) {
800                 /* Halt */
801                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
802                         usb_ep_set_halt(ep->ep);
803                 spin_unlock_irq(&epfile->ffs->eps_lock);
804                 ret = -EBADMSG;
805         } else {
806                 /* Fire the request */
807                 struct usb_request *req;
808 
809                 if (io_data->aio) {
810                         req = usb_ep_alloc_request(ep->ep, GFP_KERNEL);
811                         if (unlikely(!req))
812                                 goto error_lock;
813 
814                         req->buf      = data;
815                         req->length   = io_data->len;
816 
817                         io_data->buf = data;
818                         io_data->ep = ep->ep;
819                         io_data->req = req;
820 
821                         req->context  = io_data;
822                         req->complete = ffs_epfile_async_io_complete;
823 
824                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
825                         if (unlikely(ret)) {
826                                 usb_ep_free_request(ep->ep, req);
827                                 goto error_lock;
828                         }
829                         ret = -EIOCBQUEUED;
830 
831                         spin_unlock_irq(&epfile->ffs->eps_lock);
832                 } else {
833                         DECLARE_COMPLETION_ONSTACK(done);
834 
835                         req = ep->req;
836                         req->buf      = data;
837                         req->length   = io_data->len;
838 
839                         req->context  = &done;
840                         req->complete = ffs_epfile_io_complete;
841 
842                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
843 
844                         spin_unlock_irq(&epfile->ffs->eps_lock);
845 
846                         if (unlikely(ret < 0)) {
847                                 /* nop */
848                         } else if (unlikely(
849                                    wait_for_completion_interruptible(&done))) {
850                                 ret = -EINTR;
851                                 usb_ep_dequeue(ep->ep, req);
852                         } else {
853                                 /*
854                                  * XXX We may end up silently droping data
855                                  * here.  Since data_len (i.e. req->length) may
856                                  * be bigger than len (after being rounded up
857                                  * to maxpacketsize), we may end up with more
858                                  * data then user space has space for.
859                                  */
860                                 ret = ep->status;
861                                 if (io_data->read && ret > 0) {
862                                         ret = min_t(size_t, ret, io_data->len);
863 
864                                         if (unlikely(copy_to_user(io_data->buf,
865                                                 data, ret)))
866                                                 ret = -EFAULT;
867                                 }
868                         }
869                         kfree(data);
870                 }
871         }
872 
873         mutex_unlock(&epfile->mutex);
874         return ret;
875 
876 error_lock:
877         spin_unlock_irq(&epfile->ffs->eps_lock);
878         mutex_unlock(&epfile->mutex);
879 error:
880         kfree(data);
881         return ret;
882 }
883 
884 static ssize_t
885 ffs_epfile_write(struct file *file, const char __user *buf, size_t len,
886                  loff_t *ptr)
887 {
888         struct ffs_io_data io_data;
889 
890         ENTER();
891 
892         io_data.aio = false;
893         io_data.read = false;
894         io_data.buf = (char * __user)buf;
895         io_data.len = len;
896 
897         return ffs_epfile_io(file, &io_data);
898 }
899 
900 static ssize_t
901 ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr)
902 {
903         struct ffs_io_data io_data;
904 
905         ENTER();
906 
907         io_data.aio = false;
908         io_data.read = true;
909         io_data.buf = buf;
910         io_data.len = len;
911 
912         return ffs_epfile_io(file, &io_data);
913 }
914 
915 static int
916 ffs_epfile_open(struct inode *inode, struct file *file)
917 {
918         struct ffs_epfile *epfile = inode->i_private;
919 
920         ENTER();
921 
922         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
923                 return -ENODEV;
924 
925         file->private_data = epfile;
926         ffs_data_opened(epfile->ffs);
927 
928         return 0;
929 }
930 
931 static int ffs_aio_cancel(struct kiocb *kiocb)
932 {
933         struct ffs_io_data *io_data = kiocb->private;
934         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
935         int value;
936 
937         ENTER();
938 
939         spin_lock_irq(&epfile->ffs->eps_lock);
940 
941         if (likely(io_data && io_data->ep && io_data->req))
942                 value = usb_ep_dequeue(io_data->ep, io_data->req);
943         else
944                 value = -EINVAL;
945 
946         spin_unlock_irq(&epfile->ffs->eps_lock);
947 
948         return value;
949 }
950 
951 static ssize_t ffs_epfile_aio_write(struct kiocb *kiocb,
952                                     const struct iovec *iovec,
953                                     unsigned long nr_segs, loff_t loff)
954 {
955         struct ffs_io_data *io_data;
956 
957         ENTER();
958 
959         io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
960         if (unlikely(!io_data))
961                 return -ENOMEM;
962 
963         io_data->aio = true;
964         io_data->read = false;
965         io_data->kiocb = kiocb;
966         io_data->iovec = iovec;
967         io_data->nr_segs = nr_segs;
968         io_data->len = kiocb->ki_nbytes;
969         io_data->mm = current->mm;
970 
971         kiocb->private = io_data;
972 
973         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
974 
975         return ffs_epfile_io(kiocb->ki_filp, io_data);
976 }
977 
978 static ssize_t ffs_epfile_aio_read(struct kiocb *kiocb,
979                                    const struct iovec *iovec,
980                                    unsigned long nr_segs, loff_t loff)
981 {
982         struct ffs_io_data *io_data;
983         struct iovec *iovec_copy;
984 
985         ENTER();
986 
987         iovec_copy = kmalloc_array(nr_segs, sizeof(*iovec_copy), GFP_KERNEL);
988         if (unlikely(!iovec_copy))
989                 return -ENOMEM;
990 
991         memcpy(iovec_copy, iovec, sizeof(struct iovec)*nr_segs);
992 
993         io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
994         if (unlikely(!io_data)) {
995                 kfree(iovec_copy);
996                 return -ENOMEM;
997         }
998 
999         io_data->aio = true;
1000         io_data->read = true;
1001         io_data->kiocb = kiocb;
1002         io_data->iovec = iovec_copy;
1003         io_data->nr_segs = nr_segs;
1004         io_data->len = kiocb->ki_nbytes;
1005         io_data->mm = current->mm;
1006 
1007         kiocb->private = io_data;
1008 
1009         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1010 
1011         return ffs_epfile_io(kiocb->ki_filp, io_data);
1012 }
1013 
1014 static int
1015 ffs_epfile_release(struct inode *inode, struct file *file)
1016 {
1017         struct ffs_epfile *epfile = inode->i_private;
1018 
1019         ENTER();
1020 
1021         ffs_data_closed(epfile->ffs);
1022 
1023         return 0;
1024 }
1025 
1026 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1027                              unsigned long value)
1028 {
1029         struct ffs_epfile *epfile = file->private_data;
1030         int ret;
1031 
1032         ENTER();
1033 
1034         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1035                 return -ENODEV;
1036 
1037         spin_lock_irq(&epfile->ffs->eps_lock);
1038         if (likely(epfile->ep)) {
1039                 switch (code) {
1040                 case FUNCTIONFS_FIFO_STATUS:
1041                         ret = usb_ep_fifo_status(epfile->ep->ep);
1042                         break;
1043                 case FUNCTIONFS_FIFO_FLUSH:
1044                         usb_ep_fifo_flush(epfile->ep->ep);
1045                         ret = 0;
1046                         break;
1047                 case FUNCTIONFS_CLEAR_HALT:
1048                         ret = usb_ep_clear_halt(epfile->ep->ep);
1049                         break;
1050                 case FUNCTIONFS_ENDPOINT_REVMAP:
1051                         ret = epfile->ep->num;
1052                         break;
1053                 default:
1054                         ret = -ENOTTY;
1055                 }
1056         } else {
1057                 ret = -ENODEV;
1058         }
1059         spin_unlock_irq(&epfile->ffs->eps_lock);
1060 
1061         return ret;
1062 }
1063 
1064 static const struct file_operations ffs_epfile_operations = {
1065         .llseek =       no_llseek,
1066 
1067         .open =         ffs_epfile_open,
1068         .write =        ffs_epfile_write,
1069         .read =         ffs_epfile_read,
1070         .aio_write =    ffs_epfile_aio_write,
1071         .aio_read =     ffs_epfile_aio_read,
1072         .release =      ffs_epfile_release,
1073         .unlocked_ioctl =       ffs_epfile_ioctl,
1074 };
1075 
1076 
1077 /* File system and super block operations ***********************************/
1078 
1079 /*
1080  * Mounting the file system creates a controller file, used first for
1081  * function configuration then later for event monitoring.
1082  */
1083 
1084 static struct inode *__must_check
1085 ffs_sb_make_inode(struct super_block *sb, void *data,
1086                   const struct file_operations *fops,
1087                   const struct inode_operations *iops,
1088                   struct ffs_file_perms *perms)
1089 {
1090         struct inode *inode;
1091 
1092         ENTER();
1093 
1094         inode = new_inode(sb);
1095 
1096         if (likely(inode)) {
1097                 struct timespec current_time = CURRENT_TIME;
1098 
1099                 inode->i_ino     = get_next_ino();
1100                 inode->i_mode    = perms->mode;
1101                 inode->i_uid     = perms->uid;
1102                 inode->i_gid     = perms->gid;
1103                 inode->i_atime   = current_time;
1104                 inode->i_mtime   = current_time;
1105                 inode->i_ctime   = current_time;
1106                 inode->i_private = data;
1107                 if (fops)
1108                         inode->i_fop = fops;
1109                 if (iops)
1110                         inode->i_op  = iops;
1111         }
1112 
1113         return inode;
1114 }
1115 
1116 /* Create "regular" file */
1117 static struct inode *ffs_sb_create_file(struct super_block *sb,
1118                                         const char *name, void *data,
1119                                         const struct file_operations *fops,
1120                                         struct dentry **dentry_p)
1121 {
1122         struct ffs_data *ffs = sb->s_fs_info;
1123         struct dentry   *dentry;
1124         struct inode    *inode;
1125 
1126         ENTER();
1127 
1128         dentry = d_alloc_name(sb->s_root, name);
1129         if (unlikely(!dentry))
1130                 return NULL;
1131 
1132         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1133         if (unlikely(!inode)) {
1134                 dput(dentry);
1135                 return NULL;
1136         }
1137 
1138         d_add(dentry, inode);
1139         if (dentry_p)
1140                 *dentry_p = dentry;
1141 
1142         return inode;
1143 }
1144 
1145 /* Super block */
1146 static const struct super_operations ffs_sb_operations = {
1147         .statfs =       simple_statfs,
1148         .drop_inode =   generic_delete_inode,
1149 };
1150 
1151 struct ffs_sb_fill_data {
1152         struct ffs_file_perms perms;
1153         umode_t root_mode;
1154         const char *dev_name;
1155         struct ffs_data *ffs_data;
1156 };
1157 
1158 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1159 {
1160         struct ffs_sb_fill_data *data = _data;
1161         struct inode    *inode;
1162         struct ffs_data *ffs = data->ffs_data;
1163 
1164         ENTER();
1165 
1166         ffs->sb              = sb;
1167         data->ffs_data       = NULL;
1168         sb->s_fs_info        = ffs;
1169         sb->s_blocksize      = PAGE_CACHE_SIZE;
1170         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1171         sb->s_magic          = FUNCTIONFS_MAGIC;
1172         sb->s_op             = &ffs_sb_operations;
1173         sb->s_time_gran      = 1;
1174 
1175         /* Root inode */
1176         data->perms.mode = data->root_mode;
1177         inode = ffs_sb_make_inode(sb, NULL,
1178                                   &simple_dir_operations,
1179                                   &simple_dir_inode_operations,
1180                                   &data->perms);
1181         sb->s_root = d_make_root(inode);
1182         if (unlikely(!sb->s_root))
1183                 return -ENOMEM;
1184 
1185         /* EP0 file */
1186         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1187                                          &ffs_ep0_operations, NULL)))
1188                 return -ENOMEM;
1189 
1190         return 0;
1191 }
1192 
1193 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1194 {
1195         ENTER();
1196 
1197         if (!opts || !*opts)
1198                 return 0;
1199 
1200         for (;;) {
1201                 unsigned long value;
1202                 char *eq, *comma;
1203 
1204                 /* Option limit */
1205                 comma = strchr(opts, ',');
1206                 if (comma)
1207                         *comma = 0;
1208 
1209                 /* Value limit */
1210                 eq = strchr(opts, '=');
1211                 if (unlikely(!eq)) {
1212                         pr_err("'=' missing in %s\n", opts);
1213                         return -EINVAL;
1214                 }
1215                 *eq = 0;
1216 
1217                 /* Parse value */
1218                 if (kstrtoul(eq + 1, 0, &value)) {
1219                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1220                         return -EINVAL;
1221                 }
1222 
1223                 /* Interpret option */
1224                 switch (eq - opts) {
1225                 case 5:
1226                         if (!memcmp(opts, "rmode", 5))
1227                                 data->root_mode  = (value & 0555) | S_IFDIR;
1228                         else if (!memcmp(opts, "fmode", 5))
1229                                 data->perms.mode = (value & 0666) | S_IFREG;
1230                         else
1231                                 goto invalid;
1232                         break;
1233 
1234                 case 4:
1235                         if (!memcmp(opts, "mode", 4)) {
1236                                 data->root_mode  = (value & 0555) | S_IFDIR;
1237                                 data->perms.mode = (value & 0666) | S_IFREG;
1238                         } else {
1239                                 goto invalid;
1240                         }
1241                         break;
1242 
1243                 case 3:
1244                         if (!memcmp(opts, "uid", 3)) {
1245                                 data->perms.uid = make_kuid(current_user_ns(), value);
1246                                 if (!uid_valid(data->perms.uid)) {
1247                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1248                                         return -EINVAL;
1249                                 }
1250                         } else if (!memcmp(opts, "gid", 3)) {
1251                                 data->perms.gid = make_kgid(current_user_ns(), value);
1252                                 if (!gid_valid(data->perms.gid)) {
1253                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1254                                         return -EINVAL;
1255                                 }
1256                         } else {
1257                                 goto invalid;
1258                         }
1259                         break;
1260 
1261                 default:
1262 invalid:
1263                         pr_err("%s: invalid option\n", opts);
1264                         return -EINVAL;
1265                 }
1266 
1267                 /* Next iteration */
1268                 if (!comma)
1269                         break;
1270                 opts = comma + 1;
1271         }
1272 
1273         return 0;
1274 }
1275 
1276 /* "mount -t functionfs dev_name /dev/function" ends up here */
1277 
1278 static struct dentry *
1279 ffs_fs_mount(struct file_system_type *t, int flags,
1280               const char *dev_name, void *opts)
1281 {
1282         struct ffs_sb_fill_data data = {
1283                 .perms = {
1284                         .mode = S_IFREG | 0600,
1285                         .uid = GLOBAL_ROOT_UID,
1286                         .gid = GLOBAL_ROOT_GID,
1287                 },
1288                 .root_mode = S_IFDIR | 0500,
1289         };
1290         struct dentry *rv;
1291         int ret;
1292         void *ffs_dev;
1293         struct ffs_data *ffs;
1294 
1295         ENTER();
1296 
1297         ret = ffs_fs_parse_opts(&data, opts);
1298         if (unlikely(ret < 0))
1299                 return ERR_PTR(ret);
1300 
1301         ffs = ffs_data_new();
1302         if (unlikely(!ffs))
1303                 return ERR_PTR(-ENOMEM);
1304         ffs->file_perms = data.perms;
1305 
1306         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1307         if (unlikely(!ffs->dev_name)) {
1308                 ffs_data_put(ffs);
1309                 return ERR_PTR(-ENOMEM);
1310         }
1311 
1312         ffs_dev = ffs_acquire_dev(dev_name);
1313         if (IS_ERR(ffs_dev)) {
1314                 ffs_data_put(ffs);
1315                 return ERR_CAST(ffs_dev);
1316         }
1317         ffs->private_data = ffs_dev;
1318         data.ffs_data = ffs;
1319 
1320         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1321         if (IS_ERR(rv) && data.ffs_data) {
1322                 ffs_release_dev(data.ffs_data);
1323                 ffs_data_put(data.ffs_data);
1324         }
1325         return rv;
1326 }
1327 
1328 static void
1329 ffs_fs_kill_sb(struct super_block *sb)
1330 {
1331         ENTER();
1332 
1333         kill_litter_super(sb);
1334         if (sb->s_fs_info) {
1335                 ffs_release_dev(sb->s_fs_info);
1336                 ffs_data_put(sb->s_fs_info);
1337         }
1338 }
1339 
1340 static struct file_system_type ffs_fs_type = {
1341         .owner          = THIS_MODULE,
1342         .name           = "functionfs",
1343         .mount          = ffs_fs_mount,
1344         .kill_sb        = ffs_fs_kill_sb,
1345 };
1346 MODULE_ALIAS_FS("functionfs");
1347 
1348 
1349 /* Driver's main init/cleanup functions *************************************/
1350 
1351 static int functionfs_init(void)
1352 {
1353         int ret;
1354 
1355         ENTER();
1356 
1357         ret = register_filesystem(&ffs_fs_type);
1358         if (likely(!ret))
1359                 pr_info("file system registered\n");
1360         else
1361                 pr_err("failed registering file system (%d)\n", ret);
1362 
1363         return ret;
1364 }
1365 
1366 static void functionfs_cleanup(void)
1367 {
1368         ENTER();
1369 
1370         pr_info("unloading\n");
1371         unregister_filesystem(&ffs_fs_type);
1372 }
1373 
1374 
1375 /* ffs_data and ffs_function construction and destruction code **************/
1376 
1377 static void ffs_data_clear(struct ffs_data *ffs);
1378 static void ffs_data_reset(struct ffs_data *ffs);
1379 
1380 static void ffs_data_get(struct ffs_data *ffs)
1381 {
1382         ENTER();
1383 
1384         atomic_inc(&ffs->ref);
1385 }
1386 
1387 static void ffs_data_opened(struct ffs_data *ffs)
1388 {
1389         ENTER();
1390 
1391         atomic_inc(&ffs->ref);
1392         atomic_inc(&ffs->opened);
1393 }
1394 
1395 static void ffs_data_put(struct ffs_data *ffs)
1396 {
1397         ENTER();
1398 
1399         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1400                 pr_info("%s(): freeing\n", __func__);
1401                 ffs_data_clear(ffs);
1402                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1403                        waitqueue_active(&ffs->ep0req_completion.wait));
1404                 kfree(ffs->dev_name);
1405                 kfree(ffs);
1406         }
1407 }
1408 
1409 static void ffs_data_closed(struct ffs_data *ffs)
1410 {
1411         ENTER();
1412 
1413         if (atomic_dec_and_test(&ffs->opened)) {
1414                 ffs->state = FFS_CLOSING;
1415                 ffs_data_reset(ffs);
1416         }
1417 
1418         ffs_data_put(ffs);
1419 }
1420 
1421 static struct ffs_data *ffs_data_new(void)
1422 {
1423         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1424         if (unlikely(!ffs))
1425                 return NULL;
1426 
1427         ENTER();
1428 
1429         atomic_set(&ffs->ref, 1);
1430         atomic_set(&ffs->opened, 0);
1431         ffs->state = FFS_READ_DESCRIPTORS;
1432         mutex_init(&ffs->mutex);
1433         spin_lock_init(&ffs->eps_lock);
1434         init_waitqueue_head(&ffs->ev.waitq);
1435         init_completion(&ffs->ep0req_completion);
1436 
1437         /* XXX REVISIT need to update it in some places, or do we? */
1438         ffs->ev.can_stall = 1;
1439 
1440         return ffs;
1441 }
1442 
1443 static void ffs_data_clear(struct ffs_data *ffs)
1444 {
1445         ENTER();
1446 
1447         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags))
1448                 ffs_closed(ffs);
1449 
1450         BUG_ON(ffs->gadget);
1451 
1452         if (ffs->epfiles)
1453                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1454 
1455         kfree(ffs->raw_descs_data);
1456         kfree(ffs->raw_strings);
1457         kfree(ffs->stringtabs);
1458 }
1459 
1460 static void ffs_data_reset(struct ffs_data *ffs)
1461 {
1462         ENTER();
1463 
1464         ffs_data_clear(ffs);
1465 
1466         ffs->epfiles = NULL;
1467         ffs->raw_descs_data = NULL;
1468         ffs->raw_descs = NULL;
1469         ffs->raw_strings = NULL;
1470         ffs->stringtabs = NULL;
1471 
1472         ffs->raw_descs_length = 0;
1473         ffs->fs_descs_count = 0;
1474         ffs->hs_descs_count = 0;
1475         ffs->ss_descs_count = 0;
1476 
1477         ffs->strings_count = 0;
1478         ffs->interfaces_count = 0;
1479         ffs->eps_count = 0;
1480 
1481         ffs->ev.count = 0;
1482 
1483         ffs->state = FFS_READ_DESCRIPTORS;
1484         ffs->setup_state = FFS_NO_SETUP;
1485         ffs->flags = 0;
1486 }
1487 
1488 
1489 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1490 {
1491         struct usb_gadget_strings **lang;
1492         int first_id;
1493 
1494         ENTER();
1495 
1496         if (WARN_ON(ffs->state != FFS_ACTIVE
1497                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1498                 return -EBADFD;
1499 
1500         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1501         if (unlikely(first_id < 0))
1502                 return first_id;
1503 
1504         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1505         if (unlikely(!ffs->ep0req))
1506                 return -ENOMEM;
1507         ffs->ep0req->complete = ffs_ep0_complete;
1508         ffs->ep0req->context = ffs;
1509 
1510         lang = ffs->stringtabs;
1511         for (lang = ffs->stringtabs; *lang; ++lang) {
1512                 struct usb_string *str = (*lang)->strings;
1513                 int id = first_id;
1514                 for (; str->s; ++id, ++str)
1515                         str->id = id;
1516         }
1517 
1518         ffs->gadget = cdev->gadget;
1519         ffs_data_get(ffs);
1520         return 0;
1521 }
1522 
1523 static void functionfs_unbind(struct ffs_data *ffs)
1524 {
1525         ENTER();
1526 
1527         if (!WARN_ON(!ffs->gadget)) {
1528                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1529                 ffs->ep0req = NULL;
1530                 ffs->gadget = NULL;
1531                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1532                 ffs_data_put(ffs);
1533         }
1534 }
1535 
1536 static int ffs_epfiles_create(struct ffs_data *ffs)
1537 {
1538         struct ffs_epfile *epfile, *epfiles;
1539         unsigned i, count;
1540 
1541         ENTER();
1542 
1543         count = ffs->eps_count;
1544         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1545         if (!epfiles)
1546                 return -ENOMEM;
1547 
1548         epfile = epfiles;
1549         for (i = 1; i <= count; ++i, ++epfile) {
1550                 epfile->ffs = ffs;
1551                 mutex_init(&epfile->mutex);
1552                 init_waitqueue_head(&epfile->wait);
1553                 sprintf(epfiles->name, "ep%u",  i);
1554                 if (!unlikely(ffs_sb_create_file(ffs->sb, epfiles->name, epfile,
1555                                                  &ffs_epfile_operations,
1556                                                  &epfile->dentry))) {
1557                         ffs_epfiles_destroy(epfiles, i - 1);
1558                         return -ENOMEM;
1559                 }
1560         }
1561 
1562         ffs->epfiles = epfiles;
1563         return 0;
1564 }
1565 
1566 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1567 {
1568         struct ffs_epfile *epfile = epfiles;
1569 
1570         ENTER();
1571 
1572         for (; count; --count, ++epfile) {
1573                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1574                        waitqueue_active(&epfile->wait));
1575                 if (epfile->dentry) {
1576                         d_delete(epfile->dentry);
1577                         dput(epfile->dentry);
1578                         epfile->dentry = NULL;
1579                 }
1580         }
1581 
1582         kfree(epfiles);
1583 }
1584 
1585 
1586 static void ffs_func_eps_disable(struct ffs_function *func)
1587 {
1588         struct ffs_ep *ep         = func->eps;
1589         struct ffs_epfile *epfile = func->ffs->epfiles;
1590         unsigned count            = func->ffs->eps_count;
1591         unsigned long flags;
1592 
1593         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1594         do {
1595                 /* pending requests get nuked */
1596                 if (likely(ep->ep))
1597                         usb_ep_disable(ep->ep);
1598                 epfile->ep = NULL;
1599 
1600                 ++ep;
1601                 ++epfile;
1602         } while (--count);
1603         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1604 }
1605 
1606 static int ffs_func_eps_enable(struct ffs_function *func)
1607 {
1608         struct ffs_data *ffs      = func->ffs;
1609         struct ffs_ep *ep         = func->eps;
1610         struct ffs_epfile *epfile = ffs->epfiles;
1611         unsigned count            = ffs->eps_count;
1612         unsigned long flags;
1613         int ret = 0;
1614 
1615         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1616         do {
1617                 struct usb_endpoint_descriptor *ds;
1618                 int desc_idx;
1619 
1620                 if (ffs->gadget->speed == USB_SPEED_SUPER)
1621                         desc_idx = 2;
1622                 else if (ffs->gadget->speed == USB_SPEED_HIGH)
1623                         desc_idx = 1;
1624                 else
1625                         desc_idx = 0;
1626 
1627                 /* fall-back to lower speed if desc missing for current speed */
1628                 do {
1629                         ds = ep->descs[desc_idx];
1630                 } while (!ds && --desc_idx >= 0);
1631 
1632                 if (!ds) {
1633                         ret = -EINVAL;
1634                         break;
1635                 }
1636 
1637                 ep->ep->driver_data = ep;
1638                 ep->ep->desc = ds;
1639                 ret = usb_ep_enable(ep->ep);
1640                 if (likely(!ret)) {
1641                         epfile->ep = ep;
1642                         epfile->in = usb_endpoint_dir_in(ds);
1643                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1644                 } else {
1645                         break;
1646                 }
1647 
1648                 wake_up(&epfile->wait);
1649 
1650                 ++ep;
1651                 ++epfile;
1652         } while (--count);
1653         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1654 
1655         return ret;
1656 }
1657 
1658 
1659 /* Parsing and building descriptors and strings *****************************/
1660 
1661 /*
1662  * This validates if data pointed by data is a valid USB descriptor as
1663  * well as record how many interfaces, endpoints and strings are
1664  * required by given configuration.  Returns address after the
1665  * descriptor or NULL if data is invalid.
1666  */
1667 
1668 enum ffs_entity_type {
1669         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1670 };
1671 
1672 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1673                                    u8 *valuep,
1674                                    struct usb_descriptor_header *desc,
1675                                    void *priv);
1676 
1677 static int __must_check ffs_do_desc(char *data, unsigned len,
1678                                     ffs_entity_callback entity, void *priv)
1679 {
1680         struct usb_descriptor_header *_ds = (void *)data;
1681         u8 length;
1682         int ret;
1683 
1684         ENTER();
1685 
1686         /* At least two bytes are required: length and type */
1687         if (len < 2) {
1688                 pr_vdebug("descriptor too short\n");
1689                 return -EINVAL;
1690         }
1691 
1692         /* If we have at least as many bytes as the descriptor takes? */
1693         length = _ds->bLength;
1694         if (len < length) {
1695                 pr_vdebug("descriptor longer then available data\n");
1696                 return -EINVAL;
1697         }
1698 
1699 #define __entity_check_INTERFACE(val)  1
1700 #define __entity_check_STRING(val)     (val)
1701 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1702 #define __entity(type, val) do {                                        \
1703                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1704                 if (unlikely(!__entity_check_ ##type(val))) {           \
1705                         pr_vdebug("invalid entity's value\n");          \
1706                         return -EINVAL;                                 \
1707                 }                                                       \
1708                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1709                 if (unlikely(ret < 0)) {                                \
1710                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1711                                  (val), ret);                           \
1712                         return ret;                                     \
1713                 }                                                       \
1714         } while (0)
1715 
1716         /* Parse descriptor depending on type. */
1717         switch (_ds->bDescriptorType) {
1718         case USB_DT_DEVICE:
1719         case USB_DT_CONFIG:
1720         case USB_DT_STRING:
1721         case USB_DT_DEVICE_QUALIFIER:
1722                 /* function can't have any of those */
1723                 pr_vdebug("descriptor reserved for gadget: %d\n",
1724                       _ds->bDescriptorType);
1725                 return -EINVAL;
1726 
1727         case USB_DT_INTERFACE: {
1728                 struct usb_interface_descriptor *ds = (void *)_ds;
1729                 pr_vdebug("interface descriptor\n");
1730                 if (length != sizeof *ds)
1731                         goto inv_length;
1732 
1733                 __entity(INTERFACE, ds->bInterfaceNumber);
1734                 if (ds->iInterface)
1735                         __entity(STRING, ds->iInterface);
1736         }
1737                 break;
1738 
1739         case USB_DT_ENDPOINT: {
1740                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1741                 pr_vdebug("endpoint descriptor\n");
1742                 if (length != USB_DT_ENDPOINT_SIZE &&
1743                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1744                         goto inv_length;
1745                 __entity(ENDPOINT, ds->bEndpointAddress);
1746         }
1747                 break;
1748 
1749         case HID_DT_HID:
1750                 pr_vdebug("hid descriptor\n");
1751                 if (length != sizeof(struct hid_descriptor))
1752                         goto inv_length;
1753                 break;
1754 
1755         case USB_DT_OTG:
1756                 if (length != sizeof(struct usb_otg_descriptor))
1757                         goto inv_length;
1758                 break;
1759 
1760         case USB_DT_INTERFACE_ASSOCIATION: {
1761                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1762                 pr_vdebug("interface association descriptor\n");
1763                 if (length != sizeof *ds)
1764                         goto inv_length;
1765                 if (ds->iFunction)
1766                         __entity(STRING, ds->iFunction);
1767         }
1768                 break;
1769 
1770         case USB_DT_SS_ENDPOINT_COMP:
1771                 pr_vdebug("EP SS companion descriptor\n");
1772                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
1773                         goto inv_length;
1774                 break;
1775 
1776         case USB_DT_OTHER_SPEED_CONFIG:
1777         case USB_DT_INTERFACE_POWER:
1778         case USB_DT_DEBUG:
1779         case USB_DT_SECURITY:
1780         case USB_DT_CS_RADIO_CONTROL:
1781                 /* TODO */
1782                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1783                 return -EINVAL;
1784 
1785         default:
1786                 /* We should never be here */
1787                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1788                 return -EINVAL;
1789 
1790 inv_length:
1791                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1792                           _ds->bLength, _ds->bDescriptorType);
1793                 return -EINVAL;
1794         }
1795 
1796 #undef __entity
1797 #undef __entity_check_DESCRIPTOR
1798 #undef __entity_check_INTERFACE
1799 #undef __entity_check_STRING
1800 #undef __entity_check_ENDPOINT
1801 
1802         return length;
1803 }
1804 
1805 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1806                                      ffs_entity_callback entity, void *priv)
1807 {
1808         const unsigned _len = len;
1809         unsigned long num = 0;
1810 
1811         ENTER();
1812 
1813         for (;;) {
1814                 int ret;
1815 
1816                 if (num == count)
1817                         data = NULL;
1818 
1819                 /* Record "descriptor" entity */
1820                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1821                 if (unlikely(ret < 0)) {
1822                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1823                                  num, ret);
1824                         return ret;
1825                 }
1826 
1827                 if (!data)
1828                         return _len - len;
1829 
1830                 ret = ffs_do_desc(data, len, entity, priv);
1831                 if (unlikely(ret < 0)) {
1832                         pr_debug("%s returns %d\n", __func__, ret);
1833                         return ret;
1834                 }
1835 
1836                 len -= ret;
1837                 data += ret;
1838                 ++num;
1839         }
1840 }
1841 
1842 static int __ffs_data_do_entity(enum ffs_entity_type type,
1843                                 u8 *valuep, struct usb_descriptor_header *desc,
1844                                 void *priv)
1845 {
1846         struct ffs_data *ffs = priv;
1847 
1848         ENTER();
1849 
1850         switch (type) {
1851         case FFS_DESCRIPTOR:
1852                 break;
1853 
1854         case FFS_INTERFACE:
1855                 /*
1856                  * Interfaces are indexed from zero so if we
1857                  * encountered interface "n" then there are at least
1858                  * "n+1" interfaces.
1859                  */
1860                 if (*valuep >= ffs->interfaces_count)
1861                         ffs->interfaces_count = *valuep + 1;
1862                 break;
1863 
1864         case FFS_STRING:
1865                 /*
1866                  * Strings are indexed from 1 (0 is magic ;) reserved
1867                  * for languages list or some such)
1868                  */
1869                 if (*valuep > ffs->strings_count)
1870                         ffs->strings_count = *valuep;
1871                 break;
1872 
1873         case FFS_ENDPOINT:
1874                 /* Endpoints are indexed from 1 as well. */
1875                 if ((*valuep & USB_ENDPOINT_NUMBER_MASK) > ffs->eps_count)
1876                         ffs->eps_count = (*valuep & USB_ENDPOINT_NUMBER_MASK);
1877                 break;
1878         }
1879 
1880         return 0;
1881 }
1882 
1883 static int __ffs_data_got_descs(struct ffs_data *ffs,
1884                                 char *const _data, size_t len)
1885 {
1886         char *data = _data, *raw_descs;
1887         unsigned counts[3], flags;
1888         int ret = -EINVAL, i;
1889 
1890         ENTER();
1891 
1892         if (get_unaligned_le32(data + 4) != len)
1893                 goto error;
1894 
1895         switch (get_unaligned_le32(data)) {
1896         case FUNCTIONFS_DESCRIPTORS_MAGIC:
1897                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
1898                 data += 8;
1899                 len  -= 8;
1900                 break;
1901         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
1902                 flags = get_unaligned_le32(data + 8);
1903                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
1904                               FUNCTIONFS_HAS_HS_DESC |
1905                               FUNCTIONFS_HAS_SS_DESC)) {
1906                         ret = -ENOSYS;
1907                         goto error;
1908                 }
1909                 data += 12;
1910                 len  -= 12;
1911                 break;
1912         default:
1913                 goto error;
1914         }
1915 
1916         /* Read fs_count, hs_count and ss_count (if present) */
1917         for (i = 0; i < 3; ++i) {
1918                 if (!(flags & (1 << i))) {
1919                         counts[i] = 0;
1920                 } else if (len < 4) {
1921                         goto error;
1922                 } else {
1923                         counts[i] = get_unaligned_le32(data);
1924                         data += 4;
1925                         len  -= 4;
1926                 }
1927         }
1928 
1929         /* Read descriptors */
1930         raw_descs = data;
1931         for (i = 0; i < 3; ++i) {
1932                 if (!counts[i])
1933                         continue;
1934                 ret = ffs_do_descs(counts[i], data, len,
1935                                    __ffs_data_do_entity, ffs);
1936                 if (ret < 0)
1937                         goto error;
1938                 data += ret;
1939                 len  -= ret;
1940         }
1941 
1942         if (raw_descs == data || len) {
1943                 ret = -EINVAL;
1944                 goto error;
1945         }
1946 
1947         ffs->raw_descs_data     = _data;
1948         ffs->raw_descs          = raw_descs;
1949         ffs->raw_descs_length   = data - raw_descs;
1950         ffs->fs_descs_count     = counts[0];
1951         ffs->hs_descs_count     = counts[1];
1952         ffs->ss_descs_count     = counts[2];
1953 
1954         return 0;
1955 
1956 error:
1957         kfree(_data);
1958         return ret;
1959 }
1960 
1961 static int __ffs_data_got_strings(struct ffs_data *ffs,
1962                                   char *const _data, size_t len)
1963 {
1964         u32 str_count, needed_count, lang_count;
1965         struct usb_gadget_strings **stringtabs, *t;
1966         struct usb_string *strings, *s;
1967         const char *data = _data;
1968 
1969         ENTER();
1970 
1971         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
1972                      get_unaligned_le32(data + 4) != len))
1973                 goto error;
1974         str_count  = get_unaligned_le32(data + 8);
1975         lang_count = get_unaligned_le32(data + 12);
1976 
1977         /* if one is zero the other must be zero */
1978         if (unlikely(!str_count != !lang_count))
1979                 goto error;
1980 
1981         /* Do we have at least as many strings as descriptors need? */
1982         needed_count = ffs->strings_count;
1983         if (unlikely(str_count < needed_count))
1984                 goto error;
1985 
1986         /*
1987          * If we don't need any strings just return and free all
1988          * memory.
1989          */
1990         if (!needed_count) {
1991                 kfree(_data);
1992                 return 0;
1993         }
1994 
1995         /* Allocate everything in one chunk so there's less maintenance. */
1996         {
1997                 unsigned i = 0;
1998                 vla_group(d);
1999                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2000                         lang_count + 1);
2001                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2002                 vla_item(d, struct usb_string, strings,
2003                         lang_count*(needed_count+1));
2004 
2005                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2006 
2007                 if (unlikely(!vlabuf)) {
2008                         kfree(_data);
2009                         return -ENOMEM;
2010                 }
2011 
2012                 /* Initialize the VLA pointers */
2013                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2014                 t = vla_ptr(vlabuf, d, stringtab);
2015                 i = lang_count;
2016                 do {
2017                         *stringtabs++ = t++;
2018                 } while (--i);
2019                 *stringtabs = NULL;
2020 
2021                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2022                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2023                 t = vla_ptr(vlabuf, d, stringtab);
2024                 s = vla_ptr(vlabuf, d, strings);
2025                 strings = s;
2026         }
2027 
2028         /* For each language */
2029         data += 16;
2030         len -= 16;
2031 
2032         do { /* lang_count > 0 so we can use do-while */
2033                 unsigned needed = needed_count;
2034 
2035                 if (unlikely(len < 3))
2036                         goto error_free;
2037                 t->language = get_unaligned_le16(data);
2038                 t->strings  = s;
2039                 ++t;
2040 
2041                 data += 2;
2042                 len -= 2;
2043 
2044                 /* For each string */
2045                 do { /* str_count > 0 so we can use do-while */
2046                         size_t length = strnlen(data, len);
2047 
2048                         if (unlikely(length == len))
2049                                 goto error_free;
2050 
2051                         /*
2052                          * User may provide more strings then we need,
2053                          * if that's the case we simply ignore the
2054                          * rest
2055                          */
2056                         if (likely(needed)) {
2057                                 /*
2058                                  * s->id will be set while adding
2059                                  * function to configuration so for
2060                                  * now just leave garbage here.
2061                                  */
2062                                 s->s = data;
2063                                 --needed;
2064                                 ++s;
2065                         }
2066 
2067                         data += length + 1;
2068                         len -= length + 1;
2069                 } while (--str_count);
2070 
2071                 s->id = 0;   /* terminator */
2072                 s->s = NULL;
2073                 ++s;
2074 
2075         } while (--lang_count);
2076 
2077         /* Some garbage left? */
2078         if (unlikely(len))
2079                 goto error_free;
2080 
2081         /* Done! */
2082         ffs->stringtabs = stringtabs;
2083         ffs->raw_strings = _data;
2084 
2085         return 0;
2086 
2087 error_free:
2088         kfree(stringtabs);
2089 error:
2090         kfree(_data);
2091         return -EINVAL;
2092 }
2093 
2094 
2095 /* Events handling and management *******************************************/
2096 
2097 static void __ffs_event_add(struct ffs_data *ffs,
2098                             enum usb_functionfs_event_type type)
2099 {
2100         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2101         int neg = 0;
2102 
2103         /*
2104          * Abort any unhandled setup
2105          *
2106          * We do not need to worry about some cmpxchg() changing value
2107          * of ffs->setup_state without holding the lock because when
2108          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2109          * the source does nothing.
2110          */
2111         if (ffs->setup_state == FFS_SETUP_PENDING)
2112                 ffs->setup_state = FFS_SETUP_CANCELLED;
2113 
2114         switch (type) {
2115         case FUNCTIONFS_RESUME:
2116                 rem_type2 = FUNCTIONFS_SUSPEND;
2117                 /* FALL THROUGH */
2118         case FUNCTIONFS_SUSPEND:
2119         case FUNCTIONFS_SETUP:
2120                 rem_type1 = type;
2121                 /* Discard all similar events */
2122                 break;
2123 
2124         case FUNCTIONFS_BIND:
2125         case FUNCTIONFS_UNBIND:
2126         case FUNCTIONFS_DISABLE:
2127         case FUNCTIONFS_ENABLE:
2128                 /* Discard everything other then power management. */
2129                 rem_type1 = FUNCTIONFS_SUSPEND;
2130                 rem_type2 = FUNCTIONFS_RESUME;
2131                 neg = 1;
2132                 break;
2133 
2134         default:
2135                 BUG();
2136         }
2137 
2138         {
2139                 u8 *ev  = ffs->ev.types, *out = ev;
2140                 unsigned n = ffs->ev.count;
2141                 for (; n; --n, ++ev)
2142                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2143                                 *out++ = *ev;
2144                         else
2145                                 pr_vdebug("purging event %d\n", *ev);
2146                 ffs->ev.count = out - ffs->ev.types;
2147         }
2148 
2149         pr_vdebug("adding event %d\n", type);
2150         ffs->ev.types[ffs->ev.count++] = type;
2151         wake_up_locked(&ffs->ev.waitq);
2152 }
2153 
2154 static void ffs_event_add(struct ffs_data *ffs,
2155                           enum usb_functionfs_event_type type)
2156 {
2157         unsigned long flags;
2158         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2159         __ffs_event_add(ffs, type);
2160         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2161 }
2162 
2163 
2164 /* Bind/unbind USB function hooks *******************************************/
2165 
2166 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2167                                     struct usb_descriptor_header *desc,
2168                                     void *priv)
2169 {
2170         struct usb_endpoint_descriptor *ds = (void *)desc;
2171         struct ffs_function *func = priv;
2172         struct ffs_ep *ffs_ep;
2173         unsigned ep_desc_id, idx;
2174         static const char *speed_names[] = { "full", "high", "super" };
2175 
2176         if (type != FFS_DESCRIPTOR)
2177                 return 0;
2178 
2179         /*
2180          * If ss_descriptors is not NULL, we are reading super speed
2181          * descriptors; if hs_descriptors is not NULL, we are reading high
2182          * speed descriptors; otherwise, we are reading full speed
2183          * descriptors.
2184          */
2185         if (func->function.ss_descriptors) {
2186                 ep_desc_id = 2;
2187                 func->function.ss_descriptors[(long)valuep] = desc;
2188         } else if (func->function.hs_descriptors) {
2189                 ep_desc_id = 1;
2190                 func->function.hs_descriptors[(long)valuep] = desc;
2191         } else {
2192                 ep_desc_id = 0;
2193                 func->function.fs_descriptors[(long)valuep]    = desc;
2194         }
2195 
2196         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2197                 return 0;
2198 
2199         idx = (ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK) - 1;
2200         ffs_ep = func->eps + idx;
2201 
2202         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2203                 pr_err("two %sspeed descriptors for EP %d\n",
2204                           speed_names[ep_desc_id],
2205                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2206                 return -EINVAL;
2207         }
2208         ffs_ep->descs[ep_desc_id] = ds;
2209 
2210         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2211         if (ffs_ep->ep) {
2212                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2213                 if (!ds->wMaxPacketSize)
2214                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2215         } else {
2216                 struct usb_request *req;
2217                 struct usb_ep *ep;
2218 
2219                 pr_vdebug("autoconfig\n");
2220                 ep = usb_ep_autoconfig(func->gadget, ds);
2221                 if (unlikely(!ep))
2222                         return -ENOTSUPP;
2223                 ep->driver_data = func->eps + idx;
2224 
2225                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2226                 if (unlikely(!req))
2227                         return -ENOMEM;
2228 
2229                 ffs_ep->ep  = ep;
2230                 ffs_ep->req = req;
2231                 func->eps_revmap[ds->bEndpointAddress &
2232                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2233         }
2234         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2235 
2236         return 0;
2237 }
2238 
2239 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2240                                    struct usb_descriptor_header *desc,
2241                                    void *priv)
2242 {
2243         struct ffs_function *func = priv;
2244         unsigned idx;
2245         u8 newValue;
2246 
2247         switch (type) {
2248         default:
2249         case FFS_DESCRIPTOR:
2250                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2251                 return 0;
2252 
2253         case FFS_INTERFACE:
2254                 idx = *valuep;
2255                 if (func->interfaces_nums[idx] < 0) {
2256                         int id = usb_interface_id(func->conf, &func->function);
2257                         if (unlikely(id < 0))
2258                                 return id;
2259                         func->interfaces_nums[idx] = id;
2260                 }
2261                 newValue = func->interfaces_nums[idx];
2262                 break;
2263 
2264         case FFS_STRING:
2265                 /* String' IDs are allocated when fsf_data is bound to cdev */
2266                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2267                 break;
2268 
2269         case FFS_ENDPOINT:
2270                 /*
2271                  * USB_DT_ENDPOINT are handled in
2272                  * __ffs_func_bind_do_descs().
2273                  */
2274                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2275                         return 0;
2276 
2277                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2278                 if (unlikely(!func->eps[idx].ep))
2279                         return -EINVAL;
2280 
2281                 {
2282                         struct usb_endpoint_descriptor **descs;
2283                         descs = func->eps[idx].descs;
2284                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2285                 }
2286                 break;
2287         }
2288 
2289         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2290         *valuep = newValue;
2291         return 0;
2292 }
2293 
2294 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2295                                                 struct usb_configuration *c)
2296 {
2297         struct ffs_function *func = ffs_func_from_usb(f);
2298         struct f_fs_opts *ffs_opts =
2299                 container_of(f->fi, struct f_fs_opts, func_inst);
2300         int ret;
2301 
2302         ENTER();
2303 
2304         /*
2305          * Legacy gadget triggers binding in functionfs_ready_callback,
2306          * which already uses locking; taking the same lock here would
2307          * cause a deadlock.
2308          *
2309          * Configfs-enabled gadgets however do need ffs_dev_lock.
2310          */
2311         if (!ffs_opts->no_configfs)
2312                 ffs_dev_lock();
2313         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2314         func->ffs = ffs_opts->dev->ffs_data;
2315         if (!ffs_opts->no_configfs)
2316                 ffs_dev_unlock();
2317         if (ret)
2318                 return ERR_PTR(ret);
2319 
2320         func->conf = c;
2321         func->gadget = c->cdev->gadget;
2322 
2323         ffs_data_get(func->ffs);
2324 
2325         /*
2326          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2327          * configurations are bound in sequence with list_for_each_entry,
2328          * in each configuration its functions are bound in sequence
2329          * with list_for_each_entry, so we assume no race condition
2330          * with regard to ffs_opts->bound access
2331          */
2332         if (!ffs_opts->refcnt) {
2333                 ret = functionfs_bind(func->ffs, c->cdev);
2334                 if (ret)
2335                         return ERR_PTR(ret);
2336         }
2337         ffs_opts->refcnt++;
2338         func->function.strings = func->ffs->stringtabs;
2339 
2340         return ffs_opts;
2341 }
2342 
2343 static int _ffs_func_bind(struct usb_configuration *c,
2344                           struct usb_function *f)
2345 {
2346         struct ffs_function *func = ffs_func_from_usb(f);
2347         struct ffs_data *ffs = func->ffs;
2348 
2349         const int full = !!func->ffs->fs_descs_count;
2350         const int high = gadget_is_dualspeed(func->gadget) &&
2351                 func->ffs->hs_descs_count;
2352         const int super = gadget_is_superspeed(func->gadget) &&
2353                 func->ffs->ss_descs_count;
2354 
2355         int fs_len, hs_len, ret;
2356 
2357         /* Make it a single chunk, less management later on */
2358         vla_group(d);
2359         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2360         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2361                 full ? ffs->fs_descs_count + 1 : 0);
2362         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2363                 high ? ffs->hs_descs_count + 1 : 0);
2364         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2365                 super ? ffs->ss_descs_count + 1 : 0);
2366         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2367         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2368         char *vlabuf;
2369 
2370         ENTER();
2371 
2372         /* Has descriptors only for speeds gadget does not support */
2373         if (unlikely(!(full | high | super)))
2374                 return -ENOTSUPP;
2375 
2376         /* Allocate a single chunk, less management later on */
2377         vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2378         if (unlikely(!vlabuf))
2379                 return -ENOMEM;
2380 
2381         /* Zero */
2382         memset(vla_ptr(vlabuf, d, eps), 0, d_eps__sz);
2383         /* Copy descriptors  */
2384         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
2385                ffs->raw_descs_length);
2386 
2387         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2388         for (ret = ffs->eps_count; ret; --ret) {
2389                 struct ffs_ep *ptr;
2390 
2391                 ptr = vla_ptr(vlabuf, d, eps);
2392                 ptr[ret].num = -1;
2393         }
2394 
2395         /* Save pointers
2396          * d_eps == vlabuf, func->eps used to kfree vlabuf later
2397         */
2398         func->eps             = vla_ptr(vlabuf, d, eps);
2399         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
2400 
2401         /*
2402          * Go through all the endpoint descriptors and allocate
2403          * endpoints first, so that later we can rewrite the endpoint
2404          * numbers without worrying that it may be described later on.
2405          */
2406         if (likely(full)) {
2407                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
2408                 fs_len = ffs_do_descs(ffs->fs_descs_count,
2409                                       vla_ptr(vlabuf, d, raw_descs),
2410                                       d_raw_descs__sz,
2411                                       __ffs_func_bind_do_descs, func);
2412                 if (unlikely(fs_len < 0)) {
2413                         ret = fs_len;
2414                         goto error;
2415                 }
2416         } else {
2417                 fs_len = 0;
2418         }
2419 
2420         if (likely(high)) {
2421                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
2422                 hs_len = ffs_do_descs(ffs->hs_descs_count,
2423                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
2424                                       d_raw_descs__sz - fs_len,
2425                                       __ffs_func_bind_do_descs, func);
2426                 if (unlikely(hs_len < 0)) {
2427                         ret = hs_len;
2428                         goto error;
2429                 }
2430         } else {
2431                 hs_len = 0;
2432         }
2433 
2434         if (likely(super)) {
2435                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
2436                 ret = ffs_do_descs(ffs->ss_descs_count,
2437                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
2438                                 d_raw_descs__sz - fs_len - hs_len,
2439                                 __ffs_func_bind_do_descs, func);
2440                 if (unlikely(ret < 0))
2441                         goto error;
2442         }
2443 
2444         /*
2445          * Now handle interface numbers allocation and interface and
2446          * endpoint numbers rewriting.  We can do that in one go
2447          * now.
2448          */
2449         ret = ffs_do_descs(ffs->fs_descs_count +
2450                            (high ? ffs->hs_descs_count : 0) +
2451                            (super ? ffs->ss_descs_count : 0),
2452                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
2453                            __ffs_func_bind_do_nums, func);
2454         if (unlikely(ret < 0))
2455                 goto error;
2456 
2457         /* And we're done */
2458         ffs_event_add(ffs, FUNCTIONFS_BIND);
2459         return 0;
2460 
2461 error:
2462         /* XXX Do we need to release all claimed endpoints here? */
2463         return ret;
2464 }
2465 
2466 static int ffs_func_bind(struct usb_configuration *c,
2467                          struct usb_function *f)
2468 {
2469         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
2470 
2471         if (IS_ERR(ffs_opts))
2472                 return PTR_ERR(ffs_opts);
2473 
2474         return _ffs_func_bind(c, f);
2475 }
2476 
2477 
2478 /* Other USB function hooks *************************************************/
2479 
2480 static int ffs_func_set_alt(struct usb_function *f,
2481                             unsigned interface, unsigned alt)
2482 {
2483         struct ffs_function *func = ffs_func_from_usb(f);
2484         struct ffs_data *ffs = func->ffs;
2485         int ret = 0, intf;
2486 
2487         if (alt != (unsigned)-1) {
2488                 intf = ffs_func_revmap_intf(func, interface);
2489                 if (unlikely(intf < 0))
2490                         return intf;
2491         }
2492 
2493         if (ffs->func)
2494                 ffs_func_eps_disable(ffs->func);
2495 
2496         if (ffs->state != FFS_ACTIVE)
2497                 return -ENODEV;
2498 
2499         if (alt == (unsigned)-1) {
2500                 ffs->func = NULL;
2501                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2502                 return 0;
2503         }
2504 
2505         ffs->func = func;
2506         ret = ffs_func_eps_enable(func);
2507         if (likely(ret >= 0))
2508                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2509         return ret;
2510 }
2511 
2512 static void ffs_func_disable(struct usb_function *f)
2513 {
2514         ffs_func_set_alt(f, 0, (unsigned)-1);
2515 }
2516 
2517 static int ffs_func_setup(struct usb_function *f,
2518                           const struct usb_ctrlrequest *creq)
2519 {
2520         struct ffs_function *func = ffs_func_from_usb(f);
2521         struct ffs_data *ffs = func->ffs;
2522         unsigned long flags;
2523         int ret;
2524 
2525         ENTER();
2526 
2527         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2528         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2529         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2530         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
2531         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
2532 
2533         /*
2534          * Most requests directed to interface go through here
2535          * (notable exceptions are set/get interface) so we need to
2536          * handle them.  All other either handled by composite or
2537          * passed to usb_configuration->setup() (if one is set).  No
2538          * matter, we will handle requests directed to endpoint here
2539          * as well (as it's straightforward) but what to do with any
2540          * other request?
2541          */
2542         if (ffs->state != FFS_ACTIVE)
2543                 return -ENODEV;
2544 
2545         switch (creq->bRequestType & USB_RECIP_MASK) {
2546         case USB_RECIP_INTERFACE:
2547                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
2548                 if (unlikely(ret < 0))
2549                         return ret;
2550                 break;
2551 
2552         case USB_RECIP_ENDPOINT:
2553                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
2554                 if (unlikely(ret < 0))
2555                         return ret;
2556                 break;
2557 
2558         default:
2559                 return -EOPNOTSUPP;
2560         }
2561 
2562         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2563         ffs->ev.setup = *creq;
2564         ffs->ev.setup.wIndex = cpu_to_le16(ret);
2565         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
2566         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2567 
2568         return 0;
2569 }
2570 
2571 static void ffs_func_suspend(struct usb_function *f)
2572 {
2573         ENTER();
2574         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
2575 }
2576 
2577 static void ffs_func_resume(struct usb_function *f)
2578 {
2579         ENTER();
2580         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
2581 }
2582 
2583 
2584 /* Endpoint and interface numbers reverse mapping ***************************/
2585 
2586 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
2587 {
2588         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
2589         return num ? num : -EDOM;
2590 }
2591 
2592 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
2593 {
2594         short *nums = func->interfaces_nums;
2595         unsigned count = func->ffs->interfaces_count;
2596 
2597         for (; count; --count, ++nums) {
2598                 if (*nums >= 0 && *nums == intf)
2599                         return nums - func->interfaces_nums;
2600         }
2601 
2602         return -EDOM;
2603 }
2604 
2605 
2606 /* Devices management *******************************************************/
2607 
2608 static LIST_HEAD(ffs_devices);
2609 
2610 static struct ffs_dev *_ffs_do_find_dev(const char *name)
2611 {
2612         struct ffs_dev *dev;
2613 
2614         list_for_each_entry(dev, &ffs_devices, entry) {
2615                 if (!dev->name || !name)
2616                         continue;
2617                 if (strcmp(dev->name, name) == 0)
2618                         return dev;
2619         }
2620 
2621         return NULL;
2622 }
2623 
2624 /*
2625  * ffs_lock must be taken by the caller of this function
2626  */
2627 static struct ffs_dev *_ffs_get_single_dev(void)
2628 {
2629         struct ffs_dev *dev;
2630 
2631         if (list_is_singular(&ffs_devices)) {
2632                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
2633                 if (dev->single)
2634                         return dev;
2635         }
2636 
2637         return NULL;
2638 }
2639 
2640 /*
2641  * ffs_lock must be taken by the caller of this function
2642  */
2643 static struct ffs_dev *_ffs_find_dev(const char *name)
2644 {
2645         struct ffs_dev *dev;
2646 
2647         dev = _ffs_get_single_dev();
2648         if (dev)
2649                 return dev;
2650 
2651         return _ffs_do_find_dev(name);
2652 }
2653 
2654 /* Configfs support *********************************************************/
2655 
2656 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
2657 {
2658         return container_of(to_config_group(item), struct f_fs_opts,
2659                             func_inst.group);
2660 }
2661 
2662 static void ffs_attr_release(struct config_item *item)
2663 {
2664         struct f_fs_opts *opts = to_ffs_opts(item);
2665 
2666         usb_put_function_instance(&opts->func_inst);
2667 }
2668 
2669 static struct configfs_item_operations ffs_item_ops = {
2670         .release        = ffs_attr_release,
2671 };
2672 
2673 static struct config_item_type ffs_func_type = {
2674         .ct_item_ops    = &ffs_item_ops,
2675         .ct_owner       = THIS_MODULE,
2676 };
2677 
2678 
2679 /* Function registration interface ******************************************/
2680 
2681 static void ffs_free_inst(struct usb_function_instance *f)
2682 {
2683         struct f_fs_opts *opts;
2684 
2685         opts = to_f_fs_opts(f);
2686         ffs_dev_lock();
2687         _ffs_free_dev(opts->dev);
2688         ffs_dev_unlock();
2689         kfree(opts);
2690 }
2691 
2692 #define MAX_INST_NAME_LEN       40
2693 
2694 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
2695 {
2696         struct f_fs_opts *opts;
2697         char *ptr;
2698         const char *tmp;
2699         int name_len, ret;
2700 
2701         name_len = strlen(name) + 1;
2702         if (name_len > MAX_INST_NAME_LEN)
2703                 return -ENAMETOOLONG;
2704 
2705         ptr = kstrndup(name, name_len, GFP_KERNEL);
2706         if (!ptr)
2707                 return -ENOMEM;
2708 
2709         opts = to_f_fs_opts(fi);
2710         tmp = NULL;
2711 
2712         ffs_dev_lock();
2713 
2714         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
2715         ret = _ffs_name_dev(opts->dev, ptr);
2716         if (ret) {
2717                 kfree(ptr);
2718                 ffs_dev_unlock();
2719                 return ret;
2720         }
2721         opts->dev->name_allocated = true;
2722 
2723         ffs_dev_unlock();
2724 
2725         kfree(tmp);
2726 
2727         return 0;
2728 }
2729 
2730 static struct usb_function_instance *ffs_alloc_inst(void)
2731 {
2732         struct f_fs_opts *opts;
2733         struct ffs_dev *dev;
2734 
2735         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
2736         if (!opts)
2737                 return ERR_PTR(-ENOMEM);
2738 
2739         opts->func_inst.set_inst_name = ffs_set_inst_name;
2740         opts->func_inst.free_func_inst = ffs_free_inst;
2741         ffs_dev_lock();
2742         dev = _ffs_alloc_dev();
2743         ffs_dev_unlock();
2744         if (IS_ERR(dev)) {
2745                 kfree(opts);
2746                 return ERR_CAST(dev);
2747         }
2748         opts->dev = dev;
2749         dev->opts = opts;
2750 
2751         config_group_init_type_name(&opts->func_inst.group, "",
2752                                     &ffs_func_type);
2753         return &opts->func_inst;
2754 }
2755 
2756 static void ffs_free(struct usb_function *f)
2757 {
2758         kfree(ffs_func_from_usb(f));
2759 }
2760 
2761 static void ffs_func_unbind(struct usb_configuration *c,
2762                             struct usb_function *f)
2763 {
2764         struct ffs_function *func = ffs_func_from_usb(f);
2765         struct ffs_data *ffs = func->ffs;
2766         struct f_fs_opts *opts =
2767                 container_of(f->fi, struct f_fs_opts, func_inst);
2768         struct ffs_ep *ep = func->eps;
2769         unsigned count = ffs->eps_count;
2770         unsigned long flags;
2771 
2772         ENTER();
2773         if (ffs->func == func) {
2774                 ffs_func_eps_disable(func);
2775                 ffs->func = NULL;
2776         }
2777 
2778         if (!--opts->refcnt)
2779                 functionfs_unbind(ffs);
2780 
2781         /* cleanup after autoconfig */
2782         spin_lock_irqsave(&func->ffs->eps_lock, flags);
2783         do {
2784                 if (ep->ep && ep->req)
2785                         usb_ep_free_request(ep->ep, ep->req);
2786                 ep->req = NULL;
2787                 ++ep;
2788         } while (--count);
2789         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2790         kfree(func->eps);
2791         func->eps = NULL;
2792         /*
2793          * eps, descriptors and interfaces_nums are allocated in the
2794          * same chunk so only one free is required.
2795          */
2796         func->function.fs_descriptors = NULL;
2797         func->function.hs_descriptors = NULL;
2798         func->function.ss_descriptors = NULL;
2799         func->interfaces_nums = NULL;
2800 
2801         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
2802 }
2803 
2804 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
2805 {
2806         struct ffs_function *func;
2807 
2808         ENTER();
2809 
2810         func = kzalloc(sizeof(*func), GFP_KERNEL);
2811         if (unlikely(!func))
2812                 return ERR_PTR(-ENOMEM);
2813 
2814         func->function.name    = "Function FS Gadget";
2815 
2816         func->function.bind    = ffs_func_bind;
2817         func->function.unbind  = ffs_func_unbind;
2818         func->function.set_alt = ffs_func_set_alt;
2819         func->function.disable = ffs_func_disable;
2820         func->function.setup   = ffs_func_setup;
2821         func->function.suspend = ffs_func_suspend;
2822         func->function.resume  = ffs_func_resume;
2823         func->function.free_func = ffs_free;
2824 
2825         return &func->function;
2826 }
2827 
2828 /*
2829  * ffs_lock must be taken by the caller of this function
2830  */
2831 static struct ffs_dev *_ffs_alloc_dev(void)
2832 {
2833         struct ffs_dev *dev;
2834         int ret;
2835 
2836         if (_ffs_get_single_dev())
2837                         return ERR_PTR(-EBUSY);
2838 
2839         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2840         if (!dev)
2841                 return ERR_PTR(-ENOMEM);
2842 
2843         if (list_empty(&ffs_devices)) {
2844                 ret = functionfs_init();
2845                 if (ret) {
2846                         kfree(dev);
2847                         return ERR_PTR(ret);
2848                 }
2849         }
2850 
2851         list_add(&dev->entry, &ffs_devices);
2852 
2853         return dev;
2854 }
2855 
2856 /*
2857  * ffs_lock must be taken by the caller of this function
2858  * The caller is responsible for "name" being available whenever f_fs needs it
2859  */
2860 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
2861 {
2862         struct ffs_dev *existing;
2863 
2864         existing = _ffs_do_find_dev(name);
2865         if (existing)
2866                 return -EBUSY;
2867 
2868         dev->name = name;
2869 
2870         return 0;
2871 }
2872 
2873 /*
2874  * The caller is responsible for "name" being available whenever f_fs needs it
2875  */
2876 int ffs_name_dev(struct ffs_dev *dev, const char *name)
2877 {
2878         int ret;
2879 
2880         ffs_dev_lock();
2881         ret = _ffs_name_dev(dev, name);
2882         ffs_dev_unlock();
2883 
2884         return ret;
2885 }
2886 EXPORT_SYMBOL(ffs_name_dev);
2887 
2888 int ffs_single_dev(struct ffs_dev *dev)
2889 {
2890         int ret;
2891 
2892         ret = 0;
2893         ffs_dev_lock();
2894 
2895         if (!list_is_singular(&ffs_devices))
2896                 ret = -EBUSY;
2897         else
2898                 dev->single = true;
2899 
2900         ffs_dev_unlock();
2901         return ret;
2902 }
2903 EXPORT_SYMBOL(ffs_single_dev);
2904 
2905 /*
2906  * ffs_lock must be taken by the caller of this function
2907  */
2908 static void _ffs_free_dev(struct ffs_dev *dev)
2909 {
2910         list_del(&dev->entry);
2911         if (dev->name_allocated)
2912                 kfree(dev->name);
2913         kfree(dev);
2914         if (list_empty(&ffs_devices))
2915                 functionfs_cleanup();
2916 }
2917 
2918 static void *ffs_acquire_dev(const char *dev_name)
2919 {
2920         struct ffs_dev *ffs_dev;
2921 
2922         ENTER();
2923         ffs_dev_lock();
2924 
2925         ffs_dev = _ffs_find_dev(dev_name);
2926         if (!ffs_dev)
2927                 ffs_dev = ERR_PTR(-ENODEV);
2928         else if (ffs_dev->mounted)
2929                 ffs_dev = ERR_PTR(-EBUSY);
2930         else if (ffs_dev->ffs_acquire_dev_callback &&
2931             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
2932                 ffs_dev = ERR_PTR(-ENODEV);
2933         else
2934                 ffs_dev->mounted = true;
2935 
2936         ffs_dev_unlock();
2937         return ffs_dev;
2938 }
2939 
2940 static void ffs_release_dev(struct ffs_data *ffs_data)
2941 {
2942         struct ffs_dev *ffs_dev;
2943 
2944         ENTER();
2945         ffs_dev_lock();
2946 
2947         ffs_dev = ffs_data->private_data;
2948         if (ffs_dev) {
2949                 ffs_dev->mounted = false;
2950 
2951                 if (ffs_dev->ffs_release_dev_callback)
2952                         ffs_dev->ffs_release_dev_callback(ffs_dev);
2953         }
2954 
2955         ffs_dev_unlock();
2956 }
2957 
2958 static int ffs_ready(struct ffs_data *ffs)
2959 {
2960         struct ffs_dev *ffs_obj;
2961         int ret = 0;
2962 
2963         ENTER();
2964         ffs_dev_lock();
2965 
2966         ffs_obj = ffs->private_data;
2967         if (!ffs_obj) {
2968                 ret = -EINVAL;
2969                 goto done;
2970         }
2971         if (WARN_ON(ffs_obj->desc_ready)) {
2972                 ret = -EBUSY;
2973                 goto done;
2974         }
2975 
2976         ffs_obj->desc_ready = true;
2977         ffs_obj->ffs_data = ffs;
2978 
2979         if (ffs_obj->ffs_ready_callback)
2980                 ret = ffs_obj->ffs_ready_callback(ffs);
2981 
2982 done:
2983         ffs_dev_unlock();
2984         return ret;
2985 }
2986 
2987 static void ffs_closed(struct ffs_data *ffs)
2988 {
2989         struct ffs_dev *ffs_obj;
2990 
2991         ENTER();
2992         ffs_dev_lock();
2993 
2994         ffs_obj = ffs->private_data;
2995         if (!ffs_obj)
2996                 goto done;
2997 
2998         ffs_obj->desc_ready = false;
2999 
3000         if (ffs_obj->ffs_closed_callback)
3001                 ffs_obj->ffs_closed_callback(ffs);
3002 
3003         if (!ffs_obj->opts || ffs_obj->opts->no_configfs
3004             || !ffs_obj->opts->func_inst.group.cg_item.ci_parent)
3005                 goto done;
3006 
3007         unregister_gadget_item(ffs_obj->opts->
3008                                func_inst.group.cg_item.ci_parent->ci_parent);
3009 done:
3010         ffs_dev_unlock();
3011 }
3012 
3013 /* Misc helper functions ****************************************************/
3014 
3015 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3016 {
3017         return nonblock
3018                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3019                 : mutex_lock_interruptible(mutex);
3020 }
3021 
3022 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3023 {
3024         char *data;
3025 
3026         if (unlikely(!len))
3027                 return NULL;
3028 
3029         data = kmalloc(len, GFP_KERNEL);
3030         if (unlikely(!data))
3031                 return ERR_PTR(-ENOMEM);
3032 
3033         if (unlikely(__copy_from_user(data, buf, len))) {
3034                 kfree(data);
3035                 return ERR_PTR(-EFAULT);
3036         }
3037 
3038         pr_vdebug("Buffer from user space:\n");
3039         ffs_dump_mem("", data, len);
3040 
3041         return data;
3042 }
3043 
3044 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3045 MODULE_LICENSE("GPL");
3046 MODULE_AUTHOR("Michal Nazarewicz");
3047 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us