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                 /*
 749                  * Controller may require buffer size to be aligned to
 750                  * maxpacketsize of an out endpoint.
 751                  */
 752                 data_len = io_data->read ?
 753                            usb_ep_align_maybe(gadget, ep->ep, io_data->len) :
 754                            io_data->len;
 755
 756                 data = kmalloc(data_len, GFP_KERNEL);
 757                 if (unlikely(!data))
 758                         return -ENOMEM;
 759                 if (io_data->aio && !io_data->read) {
 760                         int i;
 761                         size_t pos = 0;
 762                         for (i = 0; i < io_data->nr_segs; i++) {
 763                                 if (unlikely(copy_from_user(&data[pos],
 764                                              io_data->iovec[i].iov_base,
 765                                              io_data->iovec[i].iov_len))) {
 766                                         ret = -EFAULT;
 767                                         goto error;
 768                                 }
 769                                 pos += io_data->iovec[i].iov_len;
 770                         }
 771                 } else {
 772                         if (!io_data->read &&
 773                             unlikely(__copy_from_user(data, io_data->buf,
 774                                                       io_data->len))) {
 775                                 ret = -EFAULT;
 776                                 goto error;
 777                         }
 778                 }
 779         }
 780
 781         /* We will be using request */
 782         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 783         if (unlikely(ret))
 784                 goto error;
 785
 786         spin_lock_irq(&epfile->ffs->eps_lock);
 787
 788         if (epfile->ep != ep) {
 789                 /* In the meantime, endpoint got disabled or changed. */
 790                 ret = -ESHUTDOWN;
 791                 spin_unlock_irq(&epfile->ffs->eps_lock);
 792         } else if (halt) {
 793                 /* Halt */
 794                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 795                         usb_ep_set_halt(ep->ep);
 796                 spin_unlock_irq(&epfile->ffs->eps_lock);
 797                 ret = -EBADMSG;
 798         } else {
 799                 /* Fire the request */
 800                 struct usb_request *req;
 801
 802                 if (io_data->aio) {
 803                         req = usb_ep_alloc_request(ep->ep, GFP_KERNEL);
 804                         if (unlikely(!req))
 805                                 goto error;
 806
 807                         req->buf      = data;
 808                         req->length   = io_data->len;
 809
 810                         io_data->buf = data;
 811                         io_data->ep = ep->ep;
 812                         io_data->req = req;
 813
 814                         req->context  = io_data;
 815                         req->complete = ffs_epfile_async_io_complete;
 816
 817                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 818                         if (unlikely(ret)) {
 819                                 usb_ep_free_request(ep->ep, req);
 820                                 goto error;
 821                         }
 822                         ret = -EIOCBQUEUED;
 823
 824                         spin_unlock_irq(&epfile->ffs->eps_lock);
 825                 } else {
 826                         DECLARE_COMPLETION_ONSTACK(done);
 827
 828                         req = ep->req;
 829                         req->buf      = data;
 830                         req->length   = io_data->len;
 831
 832                         req->context  = &done;
 833                         req->complete = ffs_epfile_io_complete;
 834
 835                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 836
 837                         spin_unlock_irq(&epfile->ffs->eps_lock);
 838
 839                         if (unlikely(ret < 0)) {
 840                                 /* nop */
 841                         } else if (unlikely(
 842                                    wait_for_completion_interruptible(&done))) {
 843                                 ret = -EINTR;
 844                                 usb_ep_dequeue(ep->ep, req);
 845                         } else {
 846                                 /*
 847                                  * XXX We may end up silently droping data
 848                                  * here.  Since data_len (i.e. req->length) may
 849                                  * be bigger than len (after being rounded up
 850                                  * to maxpacketsize), we may end up with more
 851                                  * data then user space has space for.
 852                                  */
 853                                 ret = ep->status;
 854                                 if (io_data->read && ret > 0) {
 855                                         ret = min_t(size_t, ret, io_data->len);
 856
 857                                         if (unlikely(copy_to_user(io_data->buf,
 858                                                 data, ret)))
 859                                                 ret = -EFAULT;
 860                                 }
 861                         }
 862                         kfree(data);
 863                 }
 864         }
 865
 866         mutex_unlock(&epfile->mutex);
 867         return ret;
 868 error:
 869         kfree(data);
 870         return ret;
 871 }
 872
 873 static ssize_t
 874 ffs_epfile_write(struct file *file, const char __user *buf, size_t len,
 875                  loff_t *ptr)
 876 {
 877         struct ffs_io_data io_data;
 878
 879         ENTER();
 880
 881         io_data.aio = false;
 882         io_data.read = false;
 883         io_data.buf = (char * __user)buf;
 884         io_data.len = len;
 885
 886         return ffs_epfile_io(file, &io_data);
 887 }
 888
 889 static ssize_t
 890 ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr)
 891 {
 892         struct ffs_io_data io_data;
 893
 894         ENTER();
 895
 896         io_data.aio = false;
 897         io_data.read = true;
 898         io_data.buf = buf;
 899         io_data.len = len;
 900
 901         return ffs_epfile_io(file, &io_data);
 902 }
 903
 904 static int
 905 ffs_epfile_open(struct inode *inode, struct file *file)
 906 {
 907         struct ffs_epfile *epfile = inode->i_private;
 908
 909         ENTER();
 910
 911         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 912                 return -ENODEV;
 913
 914         file->private_data = epfile;
 915         ffs_data_opened(epfile->ffs);
 916
 917         return 0;
 918 }
 919
 920 static int ffs_aio_cancel(struct kiocb *kiocb)
 921 {
 922         struct ffs_io_data *io_data = kiocb->private;
 923         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
 924         int value;
 925
 926         ENTER();
 927
 928         spin_lock_irq(&epfile->ffs->eps_lock);
 929
 930         if (likely(io_data && io_data->ep && io_data->req))
 931                 value = usb_ep_dequeue(io_data->ep, io_data->req);
 932         else
 933                 value = -EINVAL;
 934
 935         spin_unlock_irq(&epfile->ffs->eps_lock);
 936
 937         return value;
 938 }
 939
 940 static ssize_t ffs_epfile_aio_write(struct kiocb *kiocb,
 941                                     const struct iovec *iovec,
 942                                     unsigned long nr_segs, loff_t loff)
 943 {
 944         struct ffs_io_data *io_data;
 945
 946         ENTER();
 947
 948         io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
 949         if (unlikely(!io_data))
 950                 return -ENOMEM;
 951
 952         io_data->aio = true;
 953         io_data->read = false;
 954         io_data->kiocb = kiocb;
 955         io_data->iovec = iovec;
 956         io_data->nr_segs = nr_segs;
 957         io_data->len = kiocb->ki_nbytes;
 958         io_data->mm = current->mm;
 959
 960         kiocb->private = io_data;
 961
 962         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 963
 964         return ffs_epfile_io(kiocb->ki_filp, io_data);
 965 }
 966
 967 static ssize_t ffs_epfile_aio_read(struct kiocb *kiocb,
 968                                    const struct iovec *iovec,
 969                                    unsigned long nr_segs, loff_t loff)
 970 {
 971         struct ffs_io_data *io_data;
 972         struct iovec *iovec_copy;
 973
 974         ENTER();
 975
 976         iovec_copy = kmalloc_array(nr_segs, sizeof(*iovec_copy), GFP_KERNEL);
 977         if (unlikely(!iovec_copy))
 978                 return -ENOMEM;
 979
 980         memcpy(iovec_copy, iovec, sizeof(struct iovec)*nr_segs);
 981
 982         io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
 983         if (unlikely(!io_data)) {
 984                 kfree(iovec_copy);
 985                 return -ENOMEM;
 986         }
 987
 988         io_data->aio = true;
 989         io_data->read = true;
 990         io_data->kiocb = kiocb;
 991         io_data->iovec = iovec_copy;
 992         io_data->nr_segs = nr_segs;
 993         io_data->len = kiocb->ki_nbytes;
 994         io_data->mm = current->mm;
 995
 996         kiocb->private = io_data;
 997
 998         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 999
1000         return ffs_epfile_io(kiocb->ki_filp, io_data);
1001 }
1002
1003 static int
1004 ffs_epfile_release(struct inode *inode, struct file *file)
1005 {
1006         struct ffs_epfile *epfile = inode->i_private;
1007
1008         ENTER();
1009
1010         ffs_data_closed(epfile->ffs);
1011
1012         return 0;
1013 }
1014
1015 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1016                              unsigned long value)
1017 {
1018         struct ffs_epfile *epfile = file->private_data;
1019         int ret;
1020
1021         ENTER();
1022
1023         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1024                 return -ENODEV;
1025
1026         spin_lock_irq(&epfile->ffs->eps_lock);
1027         if (likely(epfile->ep)) {
1028                 switch (code) {
1029                 case FUNCTIONFS_FIFO_STATUS:
1030                         ret = usb_ep_fifo_status(epfile->ep->ep);
1031                         break;
1032                 case FUNCTIONFS_FIFO_FLUSH:
1033                         usb_ep_fifo_flush(epfile->ep->ep);
1034                         ret = 0;
1035                         break;
1036                 case FUNCTIONFS_CLEAR_HALT:
1037                         ret = usb_ep_clear_halt(epfile->ep->ep);
1038                         break;
1039                 case FUNCTIONFS_ENDPOINT_REVMAP:
1040                         ret = epfile->ep->num;
1041                         break;
1042                 default:
1043                         ret = -ENOTTY;
1044                 }
1045         } else {
1046                 ret = -ENODEV;
1047         }
1048         spin_unlock_irq(&epfile->ffs->eps_lock);
1049
1050         return ret;
1051 }
1052
1053 static const struct file_operations ffs_epfile_operations = {
1054         .llseek =       no_llseek,
1055
1056         .open =         ffs_epfile_open,
1057         .write =        ffs_epfile_write,
1058         .read =         ffs_epfile_read,
1059         .aio_write =    ffs_epfile_aio_write,
1060         .aio_read =     ffs_epfile_aio_read,
1061         .release =      ffs_epfile_release,
1062         .unlocked_ioctl =       ffs_epfile_ioctl,
1063 };
1064
1065
1066 /* File system and super block operations ***********************************/
1067
1068 /*
1069  * Mounting the file system creates a controller file, used first for
1070  * function configuration then later for event monitoring.
1071  */
1072
1073 static struct inode *__must_check
1074 ffs_sb_make_inode(struct super_block *sb, void *data,
1075                   const struct file_operations *fops,
1076                   const struct inode_operations *iops,
1077                   struct ffs_file_perms *perms)
1078 {
1079         struct inode *inode;
1080
1081         ENTER();
1082
1083         inode = new_inode(sb);
1084
1085         if (likely(inode)) {
1086                 struct timespec current_time = CURRENT_TIME;
1087
1088                 inode->i_ino     = get_next_ino();
1089                 inode->i_mode    = perms->mode;
1090                 inode->i_uid     = perms->uid;
1091                 inode->i_gid     = perms->gid;
1092                 inode->i_atime   = current_time;
1093                 inode->i_mtime   = current_time;
1094                 inode->i_ctime   = current_time;
1095                 inode->i_private = data;
1096                 if (fops)
1097                         inode->i_fop = fops;
1098                 if (iops)
1099                         inode->i_op  = iops;
1100         }
1101
1102         return inode;
1103 }
1104
1105 /* Create "regular" file */
1106 static struct inode *ffs_sb_create_file(struct super_block *sb,
1107                                         const char *name, void *data,
1108                                         const struct file_operations *fops,
1109                                         struct dentry **dentry_p)
1110 {
1111         struct ffs_data *ffs = sb->s_fs_info;
1112         struct dentry   *dentry;
1113         struct inode    *inode;
1114
1115         ENTER();
1116
1117         dentry = d_alloc_name(sb->s_root, name);
1118         if (unlikely(!dentry))
1119                 return NULL;
1120
1121         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1122         if (unlikely(!inode)) {
1123                 dput(dentry);
1124                 return NULL;
1125         }
1126
1127         d_add(dentry, inode);
1128         if (dentry_p)
1129                 *dentry_p = dentry;
1130
1131         return inode;
1132 }
1133
1134 /* Super block */
1135 static const struct super_operations ffs_sb_operations = {
1136         .statfs =       simple_statfs,
1137         .drop_inode =   generic_delete_inode,
1138 };
1139
1140 struct ffs_sb_fill_data {
1141         struct ffs_file_perms perms;
1142         umode_t root_mode;
1143         const char *dev_name;
1144         struct ffs_data *ffs_data;
1145 };
1146
1147 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1148 {
1149         struct ffs_sb_fill_data *data = _data;
1150         struct inode    *inode;
1151         struct ffs_data *ffs = data->ffs_data;
1152
1153         ENTER();
1154
1155         ffs->sb              = sb;
1156         data->ffs_data       = NULL;
1157         sb->s_fs_info        = ffs;
1158         sb->s_blocksize      = PAGE_CACHE_SIZE;
1159         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1160         sb->s_magic          = FUNCTIONFS_MAGIC;
1161         sb->s_op             = &ffs_sb_operations;
1162         sb->s_time_gran      = 1;
1163
1164         /* Root inode */
1165         data->perms.mode = data->root_mode;
1166         inode = ffs_sb_make_inode(sb, NULL,
1167                                   &simple_dir_operations,
1168                                   &simple_dir_inode_operations,
1169                                   &data->perms);
1170         sb->s_root = d_make_root(inode);
1171         if (unlikely(!sb->s_root))
1172                 return -ENOMEM;
1173
1174         /* EP0 file */
1175         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1176                                          &ffs_ep0_operations, NULL)))
1177                 return -ENOMEM;
1178
1179         return 0;
1180 }
1181
1182 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1183 {
1184         ENTER();
1185
1186         if (!opts || !*opts)
1187                 return 0;
1188
1189         for (;;) {
1190                 unsigned long value;
1191                 char *eq, *comma;
1192
1193                 /* Option limit */
1194                 comma = strchr(opts, ',');
1195                 if (comma)
1196                         *comma = 0;
1197
1198                 /* Value limit */
1199                 eq = strchr(opts, '=');
1200                 if (unlikely(!eq)) {
1201                         pr_err("'=' missing in %s\n", opts);
1202                         return -EINVAL;
1203                 }
1204                 *eq = 0;
1205
1206                 /* Parse value */
1207                 if (kstrtoul(eq + 1, 0, &value)) {
1208                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1209                         return -EINVAL;
1210                 }
1211
1212                 /* Interpret option */
1213                 switch (eq - opts) {
1214                 case 5:
1215                         if (!memcmp(opts, "rmode", 5))
1216                                 data->root_mode  = (value & 0555) | S_IFDIR;
1217                         else if (!memcmp(opts, "fmode", 5))
1218                                 data->perms.mode = (value & 0666) | S_IFREG;
1219                         else
1220                                 goto invalid;
1221                         break;
1222
1223                 case 4:
1224                         if (!memcmp(opts, "mode", 4)) {
1225                                 data->root_mode  = (value & 0555) | S_IFDIR;
1226                                 data->perms.mode = (value & 0666) | S_IFREG;
1227                         } else {
1228                                 goto invalid;
1229                         }
1230                         break;
1231
1232                 case 3:
1233                         if (!memcmp(opts, "uid", 3)) {
1234                                 data->perms.uid = make_kuid(current_user_ns(), value);
1235                                 if (!uid_valid(data->perms.uid)) {
1236                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1237                                         return -EINVAL;
1238                                 }
1239                         } else if (!memcmp(opts, "gid", 3)) {
1240                                 data->perms.gid = make_kgid(current_user_ns(), value);
1241                                 if (!gid_valid(data->perms.gid)) {
1242                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1243                                         return -EINVAL;
1244                                 }
1245                         } else {
1246                                 goto invalid;
1247                         }
1248                         break;
1249
1250                 default:
1251 invalid:
1252                         pr_err("%s: invalid option\n", opts);
1253                         return -EINVAL;
1254                 }
1255
1256                 /* Next iteration */
1257                 if (!comma)
1258                         break;
1259                 opts = comma + 1;
1260         }
1261
1262         return 0;
1263 }
1264
1265 /* "mount -t functionfs dev_name /dev/function" ends up here */
1266
1267 static struct dentry *
1268 ffs_fs_mount(struct file_system_type *t, int flags,
1269               const char *dev_name, void *opts)
1270 {
1271         struct ffs_sb_fill_data data = {
1272                 .perms = {
1273                         .mode = S_IFREG | 0600,
1274                         .uid = GLOBAL_ROOT_UID,
1275                         .gid = GLOBAL_ROOT_GID,
1276                 },
1277                 .root_mode = S_IFDIR | 0500,
1278         };
1279         struct dentry *rv;
1280         int ret;
1281         void *ffs_dev;
1282         struct ffs_data *ffs;
1283
1284         ENTER();
1285
1286         ret = ffs_fs_parse_opts(&data, opts);
1287         if (unlikely(ret < 0))
1288                 return ERR_PTR(ret);
1289
1290         ffs = ffs_data_new();
1291         if (unlikely(!ffs))
1292                 return ERR_PTR(-ENOMEM);
1293         ffs->file_perms = data.perms;
1294
1295         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1296         if (unlikely(!ffs->dev_name)) {
1297                 ffs_data_put(ffs);
1298                 return ERR_PTR(-ENOMEM);
1299         }
1300
1301         ffs_dev = ffs_acquire_dev(dev_name);
1302         if (IS_ERR(ffs_dev)) {
1303                 ffs_data_put(ffs);
1304                 return ERR_CAST(ffs_dev);
1305         }
1306         ffs->private_data = ffs_dev;
1307         data.ffs_data = ffs;
1308
1309         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1310         if (IS_ERR(rv) && data.ffs_data) {
1311                 ffs_release_dev(data.ffs_data);
1312                 ffs_data_put(data.ffs_data);
1313         }
1314         return rv;
1315 }
1316
1317 static void
1318 ffs_fs_kill_sb(struct super_block *sb)
1319 {
1320         ENTER();
1321
1322         kill_litter_super(sb);
1323         if (sb->s_fs_info) {
1324                 ffs_release_dev(sb->s_fs_info);
1325                 ffs_data_put(sb->s_fs_info);
1326         }
1327 }
1328
1329 static struct file_system_type ffs_fs_type = {
1330         .owner          = THIS_MODULE,
1331         .name           = "functionfs",
1332         .mount          = ffs_fs_mount,
1333         .kill_sb        = ffs_fs_kill_sb,
1334 };
1335 MODULE_ALIAS_FS("functionfs");
1336
1337
1338 /* Driver's main init/cleanup functions *************************************/
1339
1340 static int functionfs_init(void)
1341 {
1342         int ret;
1343
1344         ENTER();
1345
1346         ret = register_filesystem(&ffs_fs_type);
1347         if (likely(!ret))
1348                 pr_info("file system registered\n");
1349         else
1350                 pr_err("failed registering file system (%d)\n", ret);
1351
1352         return ret;
1353 }
1354
1355 static void functionfs_cleanup(void)
1356 {
1357         ENTER();
1358
1359         pr_info("unloading\n");
1360         unregister_filesystem(&ffs_fs_type);
1361 }
1362
1363
1364 /* ffs_data and ffs_function construction and destruction code **************/
1365
1366 static void ffs_data_clear(struct ffs_data *ffs);
1367 static void ffs_data_reset(struct ffs_data *ffs);
1368
1369 static void ffs_data_get(struct ffs_data *ffs)
1370 {
1371         ENTER();
1372
1373         atomic_inc(&ffs->ref);
1374 }
1375
1376 static void ffs_data_opened(struct ffs_data *ffs)
1377 {
1378         ENTER();
1379
1380         atomic_inc(&ffs->ref);
1381         atomic_inc(&ffs->opened);
1382 }
1383
1384 static void ffs_data_put(struct ffs_data *ffs)
1385 {
1386         ENTER();
1387
1388         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1389                 pr_info("%s(): freeing\n", __func__);
1390                 ffs_data_clear(ffs);
1391                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1392                        waitqueue_active(&ffs->ep0req_completion.wait));
1393                 kfree(ffs->dev_name);
1394                 kfree(ffs);
1395         }
1396 }
1397
1398 static void ffs_data_closed(struct ffs_data *ffs)
1399 {
1400         ENTER();
1401
1402         if (atomic_dec_and_test(&ffs->opened)) {
1403                 ffs->state = FFS_CLOSING;
1404                 ffs_data_reset(ffs);
1405         }
1406
1407         ffs_data_put(ffs);
1408 }
1409
1410 static struct ffs_data *ffs_data_new(void)
1411 {
1412         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1413         if (unlikely(!ffs))
1414                 return NULL;
1415
1416         ENTER();
1417
1418         atomic_set(&ffs->ref, 1);
1419         atomic_set(&ffs->opened, 0);
1420         ffs->state = FFS_READ_DESCRIPTORS;
1421         mutex_init(&ffs->mutex);
1422         spin_lock_init(&ffs->eps_lock);
1423         init_waitqueue_head(&ffs->ev.waitq);
1424         init_completion(&ffs->ep0req_completion);
1425
1426         /* XXX REVISIT need to update it in some places, or do we? */
1427         ffs->ev.can_stall = 1;
1428
1429         return ffs;
1430 }
1431
1432 static void ffs_data_clear(struct ffs_data *ffs)
1433 {
1434         ENTER();
1435
1436         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags))
1437                 ffs_closed(ffs);
1438
1439         BUG_ON(ffs->gadget);
1440
1441         if (ffs->epfiles)
1442                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1443
1444         kfree(ffs->raw_descs_data);
1445         kfree(ffs->raw_strings);
1446         kfree(ffs->stringtabs);
1447 }
1448
1449 static void ffs_data_reset(struct ffs_data *ffs)
1450 {
1451         ENTER();
1452
1453         ffs_data_clear(ffs);
1454
1455         ffs->epfiles = NULL;
1456         ffs->raw_descs_data = NULL;
1457         ffs->raw_descs = NULL;
1458         ffs->raw_strings = NULL;
1459         ffs->stringtabs = NULL;
1460
1461         ffs->raw_descs_length = 0;
1462         ffs->fs_descs_count = 0;
1463         ffs->hs_descs_count = 0;
1464         ffs->ss_descs_count = 0;
1465
1466         ffs->strings_count = 0;
1467         ffs->interfaces_count = 0;
1468         ffs->eps_count = 0;
1469
1470         ffs->ev.count = 0;
1471
1472         ffs->state = FFS_READ_DESCRIPTORS;
1473         ffs->setup_state = FFS_NO_SETUP;
1474         ffs->flags = 0;
1475 }
1476
1477
1478 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1479 {
1480         struct usb_gadget_strings **lang;
1481         int first_id;
1482
1483         ENTER();
1484
1485         if (WARN_ON(ffs->state != FFS_ACTIVE
1486                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1487                 return -EBADFD;
1488
1489         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1490         if (unlikely(first_id < 0))
1491                 return first_id;
1492
1493         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1494         if (unlikely(!ffs->ep0req))
1495                 return -ENOMEM;
1496         ffs->ep0req->complete = ffs_ep0_complete;
1497         ffs->ep0req->context = ffs;
1498
1499         lang = ffs->stringtabs;
1500         for (lang = ffs->stringtabs; *lang; ++lang) {
1501                 struct usb_string *str = (*lang)->strings;
1502                 int id = first_id;
1503                 for (; str->s; ++id, ++str)
1504                         str->id = id;
1505         }
1506
1507         ffs->gadget = cdev->gadget;
1508         ffs_data_get(ffs);
1509         return 0;
1510 }
1511
1512 static void functionfs_unbind(struct ffs_data *ffs)
1513 {
1514         ENTER();
1515
1516         if (!WARN_ON(!ffs->gadget)) {
1517                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1518                 ffs->ep0req = NULL;
1519                 ffs->gadget = NULL;
1520                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1521                 ffs_data_put(ffs);
1522         }
1523 }
1524
1525 static int ffs_epfiles_create(struct ffs_data *ffs)
1526 {
1527         struct ffs_epfile *epfile, *epfiles;
1528         unsigned i, count;
1529
1530         ENTER();
1531
1532         count = ffs->eps_count;
1533         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1534         if (!epfiles)
1535                 return -ENOMEM;
1536
1537         epfile = epfiles;
1538         for (i = 1; i <= count; ++i, ++epfile) {
1539                 epfile->ffs = ffs;
1540                 mutex_init(&epfile->mutex);
1541                 init_waitqueue_head(&epfile->wait);
1542                 sprintf(epfiles->name, "ep%u",  i);
1543                 if (!unlikely(ffs_sb_create_file(ffs->sb, epfiles->name, epfile,
1544                                                  &ffs_epfile_operations,
1545                                                  &epfile->dentry))) {
1546                         ffs_epfiles_destroy(epfiles, i - 1);
1547                         return -ENOMEM;
1548                 }
1549         }
1550
1551         ffs->epfiles = epfiles;
1552         return 0;
1553 }
1554
1555 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1556 {
1557         struct ffs_epfile *epfile = epfiles;
1558
1559         ENTER();
1560
1561         for (; count; --count, ++epfile) {
1562                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1563                        waitqueue_active(&epfile->wait));
1564                 if (epfile->dentry) {
1565                         d_delete(epfile->dentry);
1566                         dput(epfile->dentry);
1567                         epfile->dentry = NULL;
1568                 }
1569         }
1570
1571         kfree(epfiles);
1572 }
1573
1574
1575 static void ffs_func_eps_disable(struct ffs_function *func)
1576 {
1577         struct ffs_ep *ep         = func->eps;
1578         struct ffs_epfile *epfile = func->ffs->epfiles;
1579         unsigned count            = func->ffs->eps_count;
1580         unsigned long flags;
1581
1582         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1583         do {
1584                 /* pending requests get nuked */
1585                 if (likely(ep->ep))
1586                         usb_ep_disable(ep->ep);
1587                 epfile->ep = NULL;
1588
1589                 ++ep;
1590                 ++epfile;
1591         } while (--count);
1592         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1593 }
1594
1595 static int ffs_func_eps_enable(struct ffs_function *func)
1596 {
1597         struct ffs_data *ffs      = func->ffs;
1598         struct ffs_ep *ep         = func->eps;
1599         struct ffs_epfile *epfile = ffs->epfiles;
1600         unsigned count            = ffs->eps_count;
1601         unsigned long flags;
1602         int ret = 0;
1603
1604         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1605         do {
1606                 struct usb_endpoint_descriptor *ds;
1607                 int desc_idx;
1608
1609                 if (ffs->gadget->speed == USB_SPEED_SUPER)
1610                         desc_idx = 2;
1611                 else if (ffs->gadget->speed == USB_SPEED_HIGH)
1612                         desc_idx = 1;
1613                 else
1614                         desc_idx = 0;
1615
1616                 /* fall-back to lower speed if desc missing for current speed */
1617                 do {
1618                         ds = ep->descs[desc_idx];
1619                 } while (!ds && --desc_idx >= 0);
1620
1621                 if (!ds) {
1622                         ret = -EINVAL;
1623                         break;
1624                 }
1625
1626                 ep->ep->driver_data = ep;
1627                 ep->ep->desc = ds;
1628                 ret = usb_ep_enable(ep->ep);
1629                 if (likely(!ret)) {
1630                         epfile->ep = ep;
1631                         epfile->in = usb_endpoint_dir_in(ds);
1632                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1633                 } else {
1634                         break;
1635                 }
1636
1637                 wake_up(&epfile->wait);
1638
1639                 ++ep;
1640                 ++epfile;
1641         } while (--count);
1642         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1643
1644         return ret;
1645 }
1646
1647
1648 /* Parsing and building descriptors and strings *****************************/
1649
1650 /*
1651  * This validates if data pointed by data is a valid USB descriptor as
1652  * well as record how many interfaces, endpoints and strings are
1653  * required by given configuration.  Returns address after the
1654  * descriptor or NULL if data is invalid.
1655  */
1656
1657 enum ffs_entity_type {
1658         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1659 };
1660
1661 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1662                                    u8 *valuep,
1663                                    struct usb_descriptor_header *desc,
1664                                    void *priv);
1665
1666 static int __must_check ffs_do_desc(char *data, unsigned len,
1667                                     ffs_entity_callback entity, void *priv)
1668 {
1669         struct usb_descriptor_header *_ds = (void *)data;
1670         u8 length;
1671         int ret;
1672
1673         ENTER();
1674
1675         /* At least two bytes are required: length and type */
1676         if (len < 2) {
1677                 pr_vdebug("descriptor too short\n");
1678                 return -EINVAL;
1679         }
1680
1681         /* If we have at least as many bytes as the descriptor takes? */
1682         length = _ds->bLength;
1683         if (len < length) {
1684                 pr_vdebug("descriptor longer then available data\n");
1685                 return -EINVAL;
1686         }
1687
1688 #define __entity_check_INTERFACE(val)  1
1689 #define __entity_check_STRING(val)     (val)
1690 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1691 #define __entity(type, val) do {                                        \
1692                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1693                 if (unlikely(!__entity_check_ ##type(val))) {           \
1694                         pr_vdebug("invalid entity's value\n");          \
1695                         return -EINVAL;                                 \
1696                 }                                                       \
1697                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1698                 if (unlikely(ret < 0)) {                                \
1699                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1700                                  (val), ret);                           \
1701                         return ret;                                     \
1702                 }                                                       \
1703         } while (0)
1704
1705         /* Parse descriptor depending on type. */
1706         switch (_ds->bDescriptorType) {
1707         case USB_DT_DEVICE:
1708         case USB_DT_CONFIG:
1709         case USB_DT_STRING:
1710         case USB_DT_DEVICE_QUALIFIER:
1711                 /* function can't have any of those */
1712                 pr_vdebug("descriptor reserved for gadget: %d\n",
1713                       _ds->bDescriptorType);
1714                 return -EINVAL;
1715
1716         case USB_DT_INTERFACE: {
1717                 struct usb_interface_descriptor *ds = (void *)_ds;
1718                 pr_vdebug("interface descriptor\n");
1719                 if (length != sizeof *ds)
1720                         goto inv_length;
1721
1722                 __entity(INTERFACE, ds->bInterfaceNumber);
1723                 if (ds->iInterface)
1724                         __entity(STRING, ds->iInterface);
1725         }
1726                 break;
1727
1728         case USB_DT_ENDPOINT: {
1729                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1730                 pr_vdebug("endpoint descriptor\n");
1731                 if (length != USB_DT_ENDPOINT_SIZE &&
1732                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1733                         goto inv_length;
1734                 __entity(ENDPOINT, ds->bEndpointAddress);
1735         }
1736                 break;
1737
1738         case HID_DT_HID:
1739                 pr_vdebug("hid descriptor\n");
1740                 if (length != sizeof(struct hid_descriptor))
1741                         goto inv_length;
1742                 break;
1743
1744         case USB_DT_OTG:
1745                 if (length != sizeof(struct usb_otg_descriptor))
1746                         goto inv_length;
1747                 break;
1748
1749         case USB_DT_INTERFACE_ASSOCIATION: {
1750                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1751                 pr_vdebug("interface association descriptor\n");
1752                 if (length != sizeof *ds)
1753                         goto inv_length;
1754                 if (ds->iFunction)
1755                         __entity(STRING, ds->iFunction);
1756         }
1757                 break;
1758
1759         case USB_DT_SS_ENDPOINT_COMP:
1760                 pr_vdebug("EP SS companion descriptor\n");
1761                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
1762                         goto inv_length;
1763                 break;
1764
1765         case USB_DT_OTHER_SPEED_CONFIG:
1766         case USB_DT_INTERFACE_POWER:
1767         case USB_DT_DEBUG:
1768         case USB_DT_SECURITY:
1769         case USB_DT_CS_RADIO_CONTROL:
1770                 /* TODO */
1771                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1772                 return -EINVAL;
1773
1774         default:
1775                 /* We should never be here */
1776                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1777                 return -EINVAL;
1778
1779 inv_length:
1780                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1781                           _ds->bLength, _ds->bDescriptorType);
1782                 return -EINVAL;
1783         }
1784
1785 #undef __entity
1786 #undef __entity_check_DESCRIPTOR
1787 #undef __entity_check_INTERFACE
1788 #undef __entity_check_STRING
1789 #undef __entity_check_ENDPOINT
1790
1791         return length;
1792 }
1793
1794 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1795                                      ffs_entity_callback entity, void *priv)
1796 {
1797         const unsigned _len = len;
1798         unsigned long num = 0;
1799
1800         ENTER();
1801
1802         for (;;) {
1803                 int ret;
1804
1805                 if (num == count)
1806                         data = NULL;
1807
1808                 /* Record "descriptor" entity */
1809                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1810                 if (unlikely(ret < 0)) {
1811                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1812                                  num, ret);
1813                         return ret;
1814                 }
1815
1816                 if (!data)
1817                         return _len - len;
1818
1819                 ret = ffs_do_desc(data, len, entity, priv);
1820                 if (unlikely(ret < 0)) {
1821                         pr_debug("%s returns %d\n", __func__, ret);
1822                         return ret;
1823                 }
1824
1825                 len -= ret;
1826                 data += ret;
1827                 ++num;
1828         }
1829 }
1830
1831 static int __ffs_data_do_entity(enum ffs_entity_type type,
1832                                 u8 *valuep, struct usb_descriptor_header *desc,
1833                                 void *priv)
1834 {
1835         struct ffs_data *ffs = priv;
1836
1837         ENTER();
1838
1839         switch (type) {
1840         case FFS_DESCRIPTOR:
1841                 break;
1842
1843         case FFS_INTERFACE:
1844                 /*
1845                  * Interfaces are indexed from zero so if we
1846                  * encountered interface "n" then there are at least
1847                  * "n+1" interfaces.
1848                  */
1849                 if (*valuep >= ffs->interfaces_count)
1850                         ffs->interfaces_count = *valuep + 1;
1851                 break;
1852
1853         case FFS_STRING:
1854                 /*
1855                  * Strings are indexed from 1 (0 is magic ;) reserved
1856                  * for languages list or some such)
1857                  */
1858                 if (*valuep > ffs->strings_count)
1859                         ffs->strings_count = *valuep;
1860                 break;
1861
1862         case FFS_ENDPOINT:
1863                 /* Endpoints are indexed from 1 as well. */
1864                 if ((*valuep & USB_ENDPOINT_NUMBER_MASK) > ffs->eps_count)
1865                         ffs->eps_count = (*valuep & USB_ENDPOINT_NUMBER_MASK);
1866                 break;
1867         }
1868
1869         return 0;
1870 }
1871
1872 static int __ffs_data_got_descs(struct ffs_data *ffs,
1873                                 char *const _data, size_t len)
1874 {
1875         char *data = _data, *raw_descs;
1876         unsigned counts[3], flags;
1877         int ret = -EINVAL, i;
1878
1879         ENTER();
1880
1881         if (get_unaligned_le32(data + 4) != len)
1882                 goto error;
1883
1884         switch (get_unaligned_le32(data)) {
1885         case FUNCTIONFS_DESCRIPTORS_MAGIC:
1886                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
1887                 data += 8;
1888                 len  -= 8;
1889                 break;
1890         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
1891                 flags = get_unaligned_le32(data + 8);
1892                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
1893                               FUNCTIONFS_HAS_HS_DESC |
1894                               FUNCTIONFS_HAS_SS_DESC)) {
1895                         ret = -ENOSYS;
1896                         goto error;
1897                 }
1898                 data += 12;
1899                 len  -= 12;
1900                 break;
1901         default:
1902                 goto error;
1903         }
1904
1905         /* Read fs_count, hs_count and ss_count (if present) */
1906         for (i = 0; i < 3; ++i) {
1907                 if (!(flags & (1 << i))) {
1908                         counts[i] = 0;
1909                 } else if (len < 4) {
1910                         goto error;
1911                 } else {
1912                         counts[i] = get_unaligned_le32(data);
1913                         data += 4;
1914                         len  -= 4;
1915                 }
1916         }
1917
1918         /* Read descriptors */
1919         raw_descs = data;
1920         for (i = 0; i < 3; ++i) {
1921                 if (!counts[i])
1922                         continue;
1923                 ret = ffs_do_descs(counts[i], data, len,
1924                                    __ffs_data_do_entity, ffs);
1925                 if (ret < 0)
1926                         goto error;
1927                 data += ret;
1928                 len  -= ret;
1929         }
1930
1931         if (raw_descs == data || len) {
1932                 ret = -EINVAL;
1933                 goto error;
1934         }
1935
1936         ffs->raw_descs_data     = _data;
1937         ffs->raw_descs          = raw_descs;
1938         ffs->raw_descs_length   = data - raw_descs;
1939         ffs->fs_descs_count     = counts[0];
1940         ffs->hs_descs_count     = counts[1];
1941         ffs->ss_descs_count     = counts[2];
1942
1943         return 0;
1944
1945 error:
1946         kfree(_data);
1947         return ret;
1948 }
1949
1950 static int __ffs_data_got_strings(struct ffs_data *ffs,
1951                                   char *const _data, size_t len)
1952 {
1953         u32 str_count, needed_count, lang_count;
1954         struct usb_gadget_strings **stringtabs, *t;
1955         struct usb_string *strings, *s;
1956         const char *data = _data;
1957
1958         ENTER();
1959
1960         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
1961                      get_unaligned_le32(data + 4) != len))
1962                 goto error;
1963         str_count  = get_unaligned_le32(data + 8);
1964         lang_count = get_unaligned_le32(data + 12);
1965
1966         /* if one is zero the other must be zero */
1967         if (unlikely(!str_count != !lang_count))
1968                 goto error;
1969
1970         /* Do we have at least as many strings as descriptors need? */
1971         needed_count = ffs->strings_count;
1972         if (unlikely(str_count < needed_count))
1973                 goto error;
1974
1975         /*
1976          * If we don't need any strings just return and free all
1977          * memory.
1978          */
1979         if (!needed_count) {
1980                 kfree(_data);
1981                 return 0;
1982         }
1983
1984         /* Allocate everything in one chunk so there's less maintenance. */
1985         {
1986                 unsigned i = 0;
1987                 vla_group(d);
1988                 vla_item(d, struct usb_gadget_strings *, stringtabs,
1989                         lang_count + 1);
1990                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
1991                 vla_item(d, struct usb_string, strings,
1992                         lang_count*(needed_count+1));
1993
1994                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
1995
1996                 if (unlikely(!vlabuf)) {
1997                         kfree(_data);
1998                         return -ENOMEM;
1999                 }
2000
2001                 /* Initialize the VLA pointers */
2002                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2003                 t = vla_ptr(vlabuf, d, stringtab);
2004                 i = lang_count;
2005                 do {
2006                         *stringtabs++ = t++;
2007                 } while (--i);
2008                 *stringtabs = NULL;
2009
2010                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2011                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2012                 t = vla_ptr(vlabuf, d, stringtab);
2013                 s = vla_ptr(vlabuf, d, strings);
2014                 strings = s;
2015         }
2016
2017         /* For each language */
2018         data += 16;
2019         len -= 16;
2020
2021         do { /* lang_count > 0 so we can use do-while */
2022                 unsigned needed = needed_count;
2023
2024                 if (unlikely(len < 3))
2025                         goto error_free;
2026                 t->language = get_unaligned_le16(data);
2027                 t->strings  = s;
2028                 ++t;
2029
2030                 data += 2;
2031                 len -= 2;
2032
2033                 /* For each string */
2034                 do { /* str_count > 0 so we can use do-while */
2035                         size_t length = strnlen(data, len);
2036
2037                         if (unlikely(length == len))
2038                                 goto error_free;
2039
2040                         /*
2041                          * User may provide more strings then we need,
2042                          * if that's the case we simply ignore the
2043                          * rest
2044                          */
2045                         if (likely(needed)) {
2046                                 /*
2047                                  * s->id will be set while adding
2048                                  * function to configuration so for
2049                                  * now just leave garbage here.
2050                                  */
2051                                 s->s = data;
2052                                 --needed;
2053                                 ++s;
2054                         }
2055
2056                         data += length + 1;
2057                         len -= length + 1;
2058                 } while (--str_count);
2059
2060                 s->id = 0;   /* terminator */
2061                 s->s = NULL;
2062                 ++s;
2063
2064         } while (--lang_count);
2065
2066         /* Some garbage left? */
2067         if (unlikely(len))
2068                 goto error_free;
2069
2070         /* Done! */
2071         ffs->stringtabs = stringtabs;
2072         ffs->raw_strings = _data;
2073
2074         return 0;
2075
2076 error_free:
2077         kfree(stringtabs);
2078 error:
2079         kfree(_data);
2080         return -EINVAL;
2081 }
2082
2083
2084 /* Events handling and management *******************************************/
2085
2086 static void __ffs_event_add(struct ffs_data *ffs,
2087                             enum usb_functionfs_event_type type)
2088 {
2089         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2090         int neg = 0;
2091
2092         /*
2093          * Abort any unhandled setup
2094          *
2095          * We do not need to worry about some cmpxchg() changing value
2096          * of ffs->setup_state without holding the lock because when
2097          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2098          * the source does nothing.
2099          */
2100         if (ffs->setup_state == FFS_SETUP_PENDING)
2101                 ffs->setup_state = FFS_SETUP_CANCELLED;
2102
2103         switch (type) {
2104         case FUNCTIONFS_RESUME:
2105                 rem_type2 = FUNCTIONFS_SUSPEND;
2106                 /* FALL THROUGH */
2107         case FUNCTIONFS_SUSPEND:
2108         case FUNCTIONFS_SETUP:
2109                 rem_type1 = type;
2110                 /* Discard all similar events */
2111                 break;
2112
2113         case FUNCTIONFS_BIND:
2114         case FUNCTIONFS_UNBIND:
2115         case FUNCTIONFS_DISABLE:
2116         case FUNCTIONFS_ENABLE:
2117                 /* Discard everything other then power management. */
2118                 rem_type1 = FUNCTIONFS_SUSPEND;
2119                 rem_type2 = FUNCTIONFS_RESUME;
2120                 neg = 1;
2121                 break;
2122
2123         default:
2124                 BUG();
2125         }
2126
2127         {
2128                 u8 *ev  = ffs->ev.types, *out = ev;
2129                 unsigned n = ffs->ev.count;
2130                 for (; n; --n, ++ev)
2131                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2132                                 *out++ = *ev;
2133                         else
2134                                 pr_vdebug("purging event %d\n", *ev);
2135                 ffs->ev.count = out - ffs->ev.types;
2136         }
2137
2138         pr_vdebug("adding event %d\n", type);
2139         ffs->ev.types[ffs->ev.count++] = type;
2140         wake_up_locked(&ffs->ev.waitq);
2141 }
2142
2143 static void ffs_event_add(struct ffs_data *ffs,
2144                           enum usb_functionfs_event_type type)
2145 {
2146         unsigned long flags;
2147         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2148         __ffs_event_add(ffs, type);
2149         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2150 }
2151
2152
2153 /* Bind/unbind USB function hooks *******************************************/
2154
2155 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2156                                     struct usb_descriptor_header *desc,
2157                                     void *priv)
2158 {
2159         struct usb_endpoint_descriptor *ds = (void *)desc;
2160         struct ffs_function *func = priv;
2161         struct ffs_ep *ffs_ep;
2162         unsigned ep_desc_id, idx;
2163         static const char *speed_names[] = { "full", "high", "super" };
2164
2165         if (type != FFS_DESCRIPTOR)
2166                 return 0;
2167
2168         /*
2169          * If ss_descriptors is not NULL, we are reading super speed
2170          * descriptors; if hs_descriptors is not NULL, we are reading high
2171          * speed descriptors; otherwise, we are reading full speed
2172          * descriptors.
2173          */
2174         if (func->function.ss_descriptors) {
2175                 ep_desc_id = 2;
2176                 func->function.ss_descriptors[(long)valuep] = desc;
2177         } else if (func->function.hs_descriptors) {
2178                 ep_desc_id = 1;
2179                 func->function.hs_descriptors[(long)valuep] = desc;
2180         } else {
2181                 ep_desc_id = 0;
2182                 func->function.fs_descriptors[(long)valuep]    = desc;
2183         }
2184
2185         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2186                 return 0;
2187
2188         idx = (ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK) - 1;
2189         ffs_ep = func->eps + idx;
2190
2191         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2192                 pr_err("two %sspeed descriptors for EP %d\n",
2193                           speed_names[ep_desc_id],
2194                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2195                 return -EINVAL;
2196         }
2197         ffs_ep->descs[ep_desc_id] = ds;
2198
2199         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2200         if (ffs_ep->ep) {
2201                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2202                 if (!ds->wMaxPacketSize)
2203                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2204         } else {
2205                 struct usb_request *req;
2206                 struct usb_ep *ep;
2207
2208                 pr_vdebug("autoconfig\n");
2209                 ep = usb_ep_autoconfig(func->gadget, ds);
2210                 if (unlikely(!ep))
2211                         return -ENOTSUPP;
2212                 ep->driver_data = func->eps + idx;
2213
2214                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2215                 if (unlikely(!req))
2216                         return -ENOMEM;
2217
2218                 ffs_ep->ep  = ep;
2219                 ffs_ep->req = req;
2220                 func->eps_revmap[ds->bEndpointAddress &
2221                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2222         }
2223         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2224
2225         return 0;
2226 }
2227
2228 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2229                                    struct usb_descriptor_header *desc,
2230                                    void *priv)
2231 {
2232         struct ffs_function *func = priv;
2233         unsigned idx;
2234         u8 newValue;
2235
2236         switch (type) {
2237         default:
2238         case FFS_DESCRIPTOR:
2239                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2240                 return 0;
2241
2242         case FFS_INTERFACE:
2243                 idx = *valuep;
2244                 if (func->interfaces_nums[idx] < 0) {
2245                         int id = usb_interface_id(func->conf, &func->function);
2246                         if (unlikely(id < 0))
2247                                 return id;
2248                         func->interfaces_nums[idx] = id;
2249                 }
2250                 newValue = func->interfaces_nums[idx];
2251                 break;
2252
2253         case FFS_STRING:
2254                 /* String' IDs are allocated when fsf_data is bound to cdev */
2255                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2256                 break;
2257
2258         case FFS_ENDPOINT:
2259                 /*
2260                  * USB_DT_ENDPOINT are handled in
2261                  * __ffs_func_bind_do_descs().
2262                  */
2263                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2264                         return 0;
2265
2266                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2267                 if (unlikely(!func->eps[idx].ep))
2268                         return -EINVAL;
2269
2270                 {
2271                         struct usb_endpoint_descriptor **descs;
2272                         descs = func->eps[idx].descs;
2273                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2274                 }
2275                 break;
2276         }
2277
2278         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2279         *valuep = newValue;
2280         return 0;
2281 }
2282
2283 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2284                                                 struct usb_configuration *c)
2285 {
2286         struct ffs_function *func = ffs_func_from_usb(f);
2287         struct f_fs_opts *ffs_opts =
2288                 container_of(f->fi, struct f_fs_opts, func_inst);
2289         int ret;
2290
2291         ENTER();
2292
2293         /*
2294          * Legacy gadget triggers binding in functionfs_ready_callback,
2295          * which already uses locking; taking the same lock here would
2296          * cause a deadlock.
2297          *
2298          * Configfs-enabled gadgets however do need ffs_dev_lock.
2299          */
2300         if (!ffs_opts->no_configfs)
2301                 ffs_dev_lock();
2302         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2303         func->ffs = ffs_opts->dev->ffs_data;
2304         if (!ffs_opts->no_configfs)
2305                 ffs_dev_unlock();
2306         if (ret)
2307                 return ERR_PTR(ret);
2308
2309         func->conf = c;
2310         func->gadget = c->cdev->gadget;
2311
2312         ffs_data_get(func->ffs);
2313
2314         /*
2315          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2316          * configurations are bound in sequence with list_for_each_entry,
2317          * in each configuration its functions are bound in sequence
2318          * with list_for_each_entry, so we assume no race condition
2319          * with regard to ffs_opts->bound access
2320          */
2321         if (!ffs_opts->refcnt) {
2322                 ret = functionfs_bind(func->ffs, c->cdev);
2323                 if (ret)
2324                         return ERR_PTR(ret);
2325         }
2326         ffs_opts->refcnt++;
2327         func->function.strings = func->ffs->stringtabs;
2328
2329         return ffs_opts;
2330 }
2331
2332 static int _ffs_func_bind(struct usb_configuration *c,
2333                           struct usb_function *f)
2334 {
2335         struct ffs_function *func = ffs_func_from_usb(f);
2336         struct ffs_data *ffs = func->ffs;
2337
2338         const int full = !!func->ffs->fs_descs_count;
2339         const int high = gadget_is_dualspeed(func->gadget) &&
2340                 func->ffs->hs_descs_count;
2341         const int super = gadget_is_superspeed(func->gadget) &&
2342                 func->ffs->ss_descs_count;
2343
2344         int fs_len, hs_len, ret;
2345
2346         /* Make it a single chunk, less management later on */
2347         vla_group(d);
2348         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2349         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2350                 full ? ffs->fs_descs_count + 1 : 0);
2351         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2352                 high ? ffs->hs_descs_count + 1 : 0);
2353         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2354                 super ? ffs->ss_descs_count + 1 : 0);
2355         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2356         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2357         char *vlabuf;
2358
2359         ENTER();
2360
2361         /* Has descriptors only for speeds gadget does not support */
2362         if (unlikely(!(full | high | super)))
2363                 return -ENOTSUPP;
2364
2365         /* Allocate a single chunk, less management later on */
2366         vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2367         if (unlikely(!vlabuf))
2368                 return -ENOMEM;
2369
2370         /* Zero */
2371         memset(vla_ptr(vlabuf, d, eps), 0, d_eps__sz);
2372         /* Copy descriptors  */
2373         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
2374                ffs->raw_descs_length);
2375
2376         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2377         for (ret = ffs->eps_count; ret; --ret) {
2378                 struct ffs_ep *ptr;
2379
2380                 ptr = vla_ptr(vlabuf, d, eps);
2381                 ptr[ret].num = -1;
2382         }
2383
2384         /* Save pointers
2385          * d_eps == vlabuf, func->eps used to kfree vlabuf later
2386         */
2387         func->eps             = vla_ptr(vlabuf, d, eps);
2388         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
2389
2390         /*
2391          * Go through all the endpoint descriptors and allocate
2392          * endpoints first, so that later we can rewrite the endpoint
2393          * numbers without worrying that it may be described later on.
2394          */
2395         if (likely(full)) {
2396                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
2397                 fs_len = ffs_do_descs(ffs->fs_descs_count,
2398                                       vla_ptr(vlabuf, d, raw_descs),
2399                                       d_raw_descs__sz,
2400                                       __ffs_func_bind_do_descs, func);
2401                 if (unlikely(fs_len < 0)) {
2402                         ret = fs_len;
2403                         goto error;
2404                 }
2405         } else {
2406                 fs_len = 0;
2407         }
2408
2409         if (likely(high)) {
2410                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
2411                 hs_len = ffs_do_descs(ffs->hs_descs_count,
2412                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
2413                                       d_raw_descs__sz - fs_len,
2414                                       __ffs_func_bind_do_descs, func);
2415                 if (unlikely(hs_len < 0)) {
2416                         ret = hs_len;
2417                         goto error;
2418                 }
2419         } else {
2420                 hs_len = 0;
2421         }
2422
2423         if (likely(super)) {
2424                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
2425                 ret = ffs_do_descs(ffs->ss_descs_count,
2426                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
2427                                 d_raw_descs__sz - fs_len - hs_len,
2428                                 __ffs_func_bind_do_descs, func);
2429                 if (unlikely(ret < 0))
2430                         goto error;
2431         }
2432
2433         /*
2434          * Now handle interface numbers allocation and interface and
2435          * endpoint numbers rewriting.  We can do that in one go
2436          * now.
2437          */
2438         ret = ffs_do_descs(ffs->fs_descs_count +
2439                            (high ? ffs->hs_descs_count : 0) +
2440                            (super ? ffs->ss_descs_count : 0),
2441                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
2442                            __ffs_func_bind_do_nums, func);
2443         if (unlikely(ret < 0))
2444                 goto error;
2445
2446         /* And we're done */
2447         ffs_event_add(ffs, FUNCTIONFS_BIND);
2448         return 0;
2449
2450 error:
2451         /* XXX Do we need to release all claimed endpoints here? */
2452         return ret;
2453 }
2454
2455 static int ffs_func_bind(struct usb_configuration *c,
2456                          struct usb_function *f)
2457 {
2458         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
2459
2460         if (IS_ERR(ffs_opts))
2461                 return PTR_ERR(ffs_opts);
2462
2463         return _ffs_func_bind(c, f);
2464 }
2465
2466
2467 /* Other USB function hooks *************************************************/
2468
2469 static int ffs_func_set_alt(struct usb_function *f,
2470                             unsigned interface, unsigned alt)
2471 {
2472         struct ffs_function *func = ffs_func_from_usb(f);
2473         struct ffs_data *ffs = func->ffs;
2474         int ret = 0, intf;
2475
2476         if (alt != (unsigned)-1) {
2477                 intf = ffs_func_revmap_intf(func, interface);
2478                 if (unlikely(intf < 0))
2479                         return intf;
2480         }
2481
2482         if (ffs->func)
2483                 ffs_func_eps_disable(ffs->func);
2484
2485         if (ffs->state != FFS_ACTIVE)
2486                 return -ENODEV;
2487
2488         if (alt == (unsigned)-1) {
2489                 ffs->func = NULL;
2490                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2491                 return 0;
2492         }
2493
2494         ffs->func = func;
2495         ret = ffs_func_eps_enable(func);
2496         if (likely(ret >= 0))
2497                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2498         return ret;
2499 }
2500
2501 static void ffs_func_disable(struct usb_function *f)
2502 {
2503         ffs_func_set_alt(f, 0, (unsigned)-1);
2504 }
2505
2506 static int ffs_func_setup(struct usb_function *f,
2507                           const struct usb_ctrlrequest *creq)
2508 {
2509         struct ffs_function *func = ffs_func_from_usb(f);
2510         struct ffs_data *ffs = func->ffs;
2511         unsigned long flags;
2512         int ret;
2513
2514         ENTER();
2515
2516         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2517         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2518         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2519         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
2520         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
2521
2522         /*
2523          * Most requests directed to interface go through here
2524          * (notable exceptions are set/get interface) so we need to
2525          * handle them.  All other either handled by composite or
2526          * passed to usb_configuration->setup() (if one is set).  No
2527          * matter, we will handle requests directed to endpoint here
2528          * as well (as it's straightforward) but what to do with any
2529          * other request?
2530          */
2531         if (ffs->state != FFS_ACTIVE)
2532                 return -ENODEV;
2533
2534         switch (creq->bRequestType & USB_RECIP_MASK) {
2535         case USB_RECIP_INTERFACE:
2536                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
2537                 if (unlikely(ret < 0))
2538                         return ret;
2539                 break;
2540
2541         case USB_RECIP_ENDPOINT:
2542                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
2543                 if (unlikely(ret < 0))
2544                         return ret;
2545                 break;
2546
2547         default:
2548                 return -EOPNOTSUPP;
2549         }
2550
2551         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2552         ffs->ev.setup = *creq;
2553         ffs->ev.setup.wIndex = cpu_to_le16(ret);
2554         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
2555         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2556
2557         return 0;
2558 }
2559
2560 static void ffs_func_suspend(struct usb_function *f)
2561 {
2562         ENTER();
2563         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
2564 }
2565
2566 static void ffs_func_resume(struct usb_function *f)
2567 {
2568         ENTER();
2569         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
2570 }
2571
2572
2573 /* Endpoint and interface numbers reverse mapping ***************************/
2574
2575 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
2576 {
2577         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
2578         return num ? num : -EDOM;
2579 }
2580
2581 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
2582 {
2583         short *nums = func->interfaces_nums;
2584         unsigned count = func->ffs->interfaces_count;
2585
2586         for (; count; --count, ++nums) {
2587                 if (*nums >= 0 && *nums == intf)
2588                         return nums - func->interfaces_nums;
2589         }
2590
2591         return -EDOM;
2592 }
2593
2594
2595 /* Devices management *******************************************************/
2596
2597 static LIST_HEAD(ffs_devices);
2598
2599 static struct ffs_dev *_ffs_do_find_dev(const char *name)
2600 {
2601         struct ffs_dev *dev;
2602
2603         list_for_each_entry(dev, &ffs_devices, entry) {
2604                 if (!dev->name || !name)
2605                         continue;
2606                 if (strcmp(dev->name, name) == 0)
2607                         return dev;
2608         }
2609
2610         return NULL;
2611 }
2612
2613 /*
2614  * ffs_lock must be taken by the caller of this function
2615  */
2616 static struct ffs_dev *_ffs_get_single_dev(void)
2617 {
2618         struct ffs_dev *dev;
2619
2620         if (list_is_singular(&ffs_devices)) {
2621                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
2622                 if (dev->single)
2623                         return dev;
2624         }
2625
2626         return NULL;
2627 }
2628
2629 /*
2630  * ffs_lock must be taken by the caller of this function
2631  */
2632 static struct ffs_dev *_ffs_find_dev(const char *name)
2633 {
2634         struct ffs_dev *dev;
2635
2636         dev = _ffs_get_single_dev();
2637         if (dev)
2638                 return dev;
2639
2640         return _ffs_do_find_dev(name);
2641 }
2642
2643 /* Configfs support *********************************************************/
2644
2645 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
2646 {
2647         return container_of(to_config_group(item), struct f_fs_opts,
2648                             func_inst.group);
2649 }
2650
2651 static void ffs_attr_release(struct config_item *item)
2652 {
2653         struct f_fs_opts *opts = to_ffs_opts(item);
2654
2655         usb_put_function_instance(&opts->func_inst);
2656 }
2657
2658 static struct configfs_item_operations ffs_item_ops = {
2659         .release        = ffs_attr_release,
2660 };
2661
2662 static struct config_item_type ffs_func_type = {
2663         .ct_item_ops    = &ffs_item_ops,
2664         .ct_owner       = THIS_MODULE,
2665 };
2666
2667
2668 /* Function registration interface ******************************************/
2669
2670 static void ffs_free_inst(struct usb_function_instance *f)
2671 {
2672         struct f_fs_opts *opts;
2673
2674         opts = to_f_fs_opts(f);
2675         ffs_dev_lock();
2676         _ffs_free_dev(opts->dev);
2677         ffs_dev_unlock();
2678         kfree(opts);
2679 }
2680
2681 #define MAX_INST_NAME_LEN       40
2682
2683 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
2684 {
2685         struct f_fs_opts *opts;
2686         char *ptr;
2687         const char *tmp;
2688         int name_len, ret;
2689
2690         name_len = strlen(name) + 1;
2691         if (name_len > MAX_INST_NAME_LEN)
2692                 return -ENAMETOOLONG;
2693
2694         ptr = kstrndup(name, name_len, GFP_KERNEL);
2695         if (!ptr)
2696                 return -ENOMEM;
2697
2698         opts = to_f_fs_opts(fi);
2699         tmp = NULL;
2700
2701         ffs_dev_lock();
2702
2703         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
2704         ret = _ffs_name_dev(opts->dev, ptr);
2705         if (ret) {
2706                 kfree(ptr);
2707                 ffs_dev_unlock();
2708                 return ret;
2709         }
2710         opts->dev->name_allocated = true;
2711
2712         ffs_dev_unlock();
2713
2714         kfree(tmp);
2715
2716         return 0;
2717 }
2718
2719 static struct usb_function_instance *ffs_alloc_inst(void)
2720 {
2721         struct f_fs_opts *opts;
2722         struct ffs_dev *dev;
2723
2724         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
2725         if (!opts)
2726                 return ERR_PTR(-ENOMEM);
2727
2728         opts->func_inst.set_inst_name = ffs_set_inst_name;
2729         opts->func_inst.free_func_inst = ffs_free_inst;
2730         ffs_dev_lock();
2731         dev = _ffs_alloc_dev();
2732         ffs_dev_unlock();
2733         if (IS_ERR(dev)) {
2734                 kfree(opts);
2735                 return ERR_CAST(dev);
2736         }
2737         opts->dev = dev;
2738         dev->opts = opts;
2739
2740         config_group_init_type_name(&opts->func_inst.group, "",
2741                                     &ffs_func_type);
2742         return &opts->func_inst;
2743 }
2744
2745 static void ffs_free(struct usb_function *f)
2746 {
2747         kfree(ffs_func_from_usb(f));
2748 }
2749
2750 static void ffs_func_unbind(struct usb_configuration *c,
2751                             struct usb_function *f)
2752 {
2753         struct ffs_function *func = ffs_func_from_usb(f);
2754         struct ffs_data *ffs = func->ffs;
2755         struct f_fs_opts *opts =
2756                 container_of(f->fi, struct f_fs_opts, func_inst);
2757         struct ffs_ep *ep = func->eps;
2758         unsigned count = ffs->eps_count;
2759         unsigned long flags;
2760
2761         ENTER();
2762         if (ffs->func == func) {
2763                 ffs_func_eps_disable(func);
2764                 ffs->func = NULL;
2765         }
2766
2767         if (!--opts->refcnt)
2768                 functionfs_unbind(ffs);
2769
2770         /* cleanup after autoconfig */
2771         spin_lock_irqsave(&func->ffs->eps_lock, flags);
2772         do {
2773                 if (ep->ep && ep->req)
2774                         usb_ep_free_request(ep->ep, ep->req);
2775                 ep->req = NULL;
2776                 ++ep;
2777         } while (--count);
2778         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2779         kfree(func->eps);
2780         func->eps = NULL;
2781         /*
2782          * eps, descriptors and interfaces_nums are allocated in the
2783          * same chunk so only one free is required.
2784          */
2785         func->function.fs_descriptors = NULL;
2786         func->function.hs_descriptors = NULL;
2787         func->function.ss_descriptors = NULL;
2788         func->interfaces_nums = NULL;
2789
2790         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
2791 }
2792
2793 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
2794 {
2795         struct ffs_function *func;
2796
2797         ENTER();
2798
2799         func = kzalloc(sizeof(*func), GFP_KERNEL);
2800         if (unlikely(!func))
2801                 return ERR_PTR(-ENOMEM);
2802
2803         func->function.name    = "Function FS Gadget";
2804
2805         func->function.bind    = ffs_func_bind;
2806         func->function.unbind  = ffs_func_unbind;
2807         func->function.set_alt = ffs_func_set_alt;
2808         func->function.disable = ffs_func_disable;
2809         func->function.setup   = ffs_func_setup;
2810         func->function.suspend = ffs_func_suspend;
2811         func->function.resume  = ffs_func_resume;
2812         func->function.free_func = ffs_free;
2813
2814         return &func->function;
2815 }
2816
2817 /*
2818  * ffs_lock must be taken by the caller of this function
2819  */
2820 static struct ffs_dev *_ffs_alloc_dev(void)
2821 {
2822         struct ffs_dev *dev;
2823         int ret;
2824
2825         if (_ffs_get_single_dev())
2826                         return ERR_PTR(-EBUSY);
2827
2828         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2829         if (!dev)
2830                 return ERR_PTR(-ENOMEM);
2831
2832         if (list_empty(&ffs_devices)) {
2833                 ret = functionfs_init();
2834                 if (ret) {
2835                         kfree(dev);
2836                         return ERR_PTR(ret);
2837                 }
2838         }
2839
2840         list_add(&dev->entry, &ffs_devices);
2841
2842         return dev;
2843 }
2844
2845 /*
2846  * ffs_lock must be taken by the caller of this function
2847  * The caller is responsible for "name" being available whenever f_fs needs it
2848  */
2849 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
2850 {
2851         struct ffs_dev *existing;
2852
2853         existing = _ffs_do_find_dev(name);
2854         if (existing)
2855                 return -EBUSY;
2856
2857         dev->name = name;
2858
2859         return 0;
2860 }
2861
2862 /*
2863  * The caller is responsible for "name" being available whenever f_fs needs it
2864  */
2865 int ffs_name_dev(struct ffs_dev *dev, const char *name)
2866 {
2867         int ret;
2868
2869         ffs_dev_lock();
2870         ret = _ffs_name_dev(dev, name);
2871         ffs_dev_unlock();
2872
2873         return ret;
2874 }
2875 EXPORT_SYMBOL(ffs_name_dev);
2876
2877 int ffs_single_dev(struct ffs_dev *dev)
2878 {
2879         int ret;
2880
2881         ret = 0;
2882         ffs_dev_lock();
2883
2884         if (!list_is_singular(&ffs_devices))
2885                 ret = -EBUSY;
2886         else
2887                 dev->single = true;
2888
2889         ffs_dev_unlock();
2890         return ret;
2891 }
2892 EXPORT_SYMBOL(ffs_single_dev);
2893
2894 /*
2895  * ffs_lock must be taken by the caller of this function
2896  */
2897 static void _ffs_free_dev(struct ffs_dev *dev)
2898 {
2899         list_del(&dev->entry);
2900         if (dev->name_allocated)
2901                 kfree(dev->name);
2902         kfree(dev);
2903         if (list_empty(&ffs_devices))
2904                 functionfs_cleanup();
2905 }
2906
2907 static void *ffs_acquire_dev(const char *dev_name)
2908 {
2909         struct ffs_dev *ffs_dev;
2910
2911         ENTER();
2912         ffs_dev_lock();
2913
2914         ffs_dev = _ffs_find_dev(dev_name);
2915         if (!ffs_dev)
2916                 ffs_dev = ERR_PTR(-ENODEV);
2917         else if (ffs_dev->mounted)
2918                 ffs_dev = ERR_PTR(-EBUSY);
2919         else if (ffs_dev->ffs_acquire_dev_callback &&
2920             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
2921                 ffs_dev = ERR_PTR(-ENODEV);
2922         else
2923                 ffs_dev->mounted = true;
2924
2925         ffs_dev_unlock();
2926         return ffs_dev;
2927 }
2928
2929 static void ffs_release_dev(struct ffs_data *ffs_data)
2930 {
2931         struct ffs_dev *ffs_dev;
2932
2933         ENTER();
2934         ffs_dev_lock();
2935
2936         ffs_dev = ffs_data->private_data;
2937         if (ffs_dev) {
2938                 ffs_dev->mounted = false;
2939
2940                 if (ffs_dev->ffs_release_dev_callback)
2941                         ffs_dev->ffs_release_dev_callback(ffs_dev);
2942         }
2943
2944         ffs_dev_unlock();
2945 }
2946
2947 static int ffs_ready(struct ffs_data *ffs)
2948 {
2949         struct ffs_dev *ffs_obj;
2950         int ret = 0;
2951
2952         ENTER();
2953         ffs_dev_lock();
2954
2955         ffs_obj = ffs->private_data;
2956         if (!ffs_obj) {
2957                 ret = -EINVAL;
2958                 goto done;
2959         }
2960         if (WARN_ON(ffs_obj->desc_ready)) {
2961                 ret = -EBUSY;
2962                 goto done;
2963         }
2964
2965         ffs_obj->desc_ready = true;
2966         ffs_obj->ffs_data = ffs;
2967
2968         if (ffs_obj->ffs_ready_callback)
2969                 ret = ffs_obj->ffs_ready_callback(ffs);
2970
2971 done:
2972         ffs_dev_unlock();
2973         return ret;
2974 }
2975
2976 static void ffs_closed(struct ffs_data *ffs)
2977 {
2978         struct ffs_dev *ffs_obj;
2979
2980         ENTER();
2981         ffs_dev_lock();
2982
2983         ffs_obj = ffs->private_data;
2984         if (!ffs_obj)
2985                 goto done;
2986
2987         ffs_obj->desc_ready = false;
2988
2989         if (ffs_obj->ffs_closed_callback)
2990                 ffs_obj->ffs_closed_callback(ffs);
2991
2992         if (!ffs_obj->opts || ffs_obj->opts->no_configfs
2993             || !ffs_obj->opts->func_inst.group.cg_item.ci_parent)
2994                 goto done;
2995
2996         unregister_gadget_item(ffs_obj->opts->
2997                                func_inst.group.cg_item.ci_parent->ci_parent);
2998 done:
2999         ffs_dev_unlock();
3000 }
3001
3002 /* Misc helper functions ****************************************************/
3003
3004 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3005 {
3006         return nonblock
3007                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3008                 : mutex_lock_interruptible(mutex);
3009 }
3010
3011 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3012 {
3013         char *data;
3014
3015         if (unlikely(!len))
3016                 return NULL;
3017
3018         data = kmalloc(len, GFP_KERNEL);
3019         if (unlikely(!data))
3020                 return ERR_PTR(-ENOMEM);
3021
3022         if (unlikely(__copy_from_user(data, buf, len))) {
3023                 kfree(data);
3024                 return ERR_PTR(-EFAULT);
3025         }
3026
3027         pr_vdebug("Buffer from user space:\n");
3028         ffs_dump_mem("", data, len);
3029
3030         return data;
3031 }
3032
3033 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3034 MODULE_LICENSE("GPL");
3035 MODULE_AUTHOR("Michal Nazarewicz");