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 <[email protected]>
   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 <asm/unaligned.h>
  26
  27 #include <linux/usb/composite.h>
  28 #include <linux/usb/functionfs.h>
  29
  30
  31 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  32
  33
  34 /* Debugging ****************************************************************/
  35
  36 #ifdef VERBOSE_DEBUG
  37 #ifndef pr_vdebug
  38 #  define pr_vdebug pr_debug
  39 #endif /* pr_vdebug */
  40 #  define ffs_dump_mem(prefix, ptr, len) \
  41         print_hex_dump_bytes(pr_fmt(prefix ": "), DUMP_PREFIX_NONE, ptr, len)
  42 #else
  43 #ifndef pr_vdebug
  44 #  define pr_vdebug(...)                 do { } while (0)
  45 #endif /* pr_vdebug */
  46 #  define ffs_dump_mem(prefix, ptr, len) do { } while (0)
  47 #endif /* VERBOSE_DEBUG */
  48
  49 #define ENTER()    pr_vdebug("%s()\n", __func__)
  50
  51
  52 /* The data structure and setup file ****************************************/
  53
  54 enum ffs_state {
  55         /*
  56          * Waiting for descriptors and strings.
  57          *
  58          * In this state no open(2), read(2) or write(2) on epfiles
  59          * may succeed (which should not be the problem as there
  60          * should be no such files opened in the first place).
  61          */
  62         FFS_READ_DESCRIPTORS,
  63         FFS_READ_STRINGS,
  64
  65         /*
  66          * We've got descriptors and strings.  We are or have called
  67          * functionfs_ready_callback().  functionfs_bind() may have
  68          * been called but we don't know.
  69          *
  70          * This is the only state in which operations on epfiles may
  71          * succeed.
  72          */
  73         FFS_ACTIVE,
  74
  75         /*
  76          * All endpoints have been closed.  This state is also set if
  77          * we encounter an unrecoverable error.  The only
  78          * unrecoverable error is situation when after reading strings
  79          * from user space we fail to initialise epfiles or
  80          * functionfs_ready_callback() returns with error (<0).
  81          *
  82          * In this state no open(2), read(2) or write(2) (both on ep0
  83          * as well as epfile) may succeed (at this point epfiles are
  84          * unlinked and all closed so this is not a problem; ep0 is
  85          * also closed but ep0 file exists and so open(2) on ep0 must
  86          * fail).
  87          */
  88         FFS_CLOSING
  89 };
  90
  91
  92 enum ffs_setup_state {
  93         /* There is no setup request pending. */
  94         FFS_NO_SETUP,
  95         /*
  96          * User has read events and there was a setup request event
  97          * there.  The next read/write on ep0 will handle the
  98          * request.
  99          */
 100         FFS_SETUP_PENDING,
 101         /*
 102          * There was event pending but before user space handled it
 103          * some other event was introduced which canceled existing
 104          * setup.  If this state is set read/write on ep0 return
 105          * -EIDRM.  This state is only set when adding event.
 106          */
 107         FFS_SETUP_CANCELED
 108 };
 109
 110
 111
 112 struct ffs_epfile;
 113 struct ffs_function;
 114
 115 struct ffs_data {
 116         struct usb_gadget               *gadget;
 117
 118         /*
 119          * Protect access read/write operations, only one read/write
 120          * at a time.  As a consequence protects ep0req and company.
 121          * While setup request is being processed (queued) this is
 122          * held.
 123          */
 124         struct mutex                    mutex;
 125
 126         /*
 127          * Protect access to endpoint related structures (basically
 128          * usb_ep_queue(), usb_ep_dequeue(), etc. calls) except for
 129          * endpoint zero.
 130          */
 131         spinlock_t                      eps_lock;
 132
 133         /*
 134          * XXX REVISIT do we need our own request? Since we are not
 135          * handling setup requests immediately user space may be so
 136          * slow that another setup will be sent to the gadget but this
 137          * time not to us but another function and then there could be
 138          * a race.  Is that the case? Or maybe we can use cdev->req
 139          * after all, maybe we just need some spinlock for that?
 140          */
 141         struct usb_request              *ep0req;                /* P: mutex */
 142         struct completion               ep0req_completion;      /* P: mutex */
 143         int                             ep0req_status;          /* P: mutex */
 144
 145         /* reference counter */
 146         atomic_t                        ref;
 147         /* how many files are opened (EP0 and others) */
 148         atomic_t                        opened;
 149
 150         /* EP0 state */
 151         enum ffs_state                  state;
 152
 153         /*
 154          * Possible transitions:
 155          * + FFS_NO_SETUP       -> FFS_SETUP_PENDING  -- P: ev.waitq.lock
 156          *               happens only in ep0 read which is P: mutex
 157          * + FFS_SETUP_PENDING  -> FFS_NO_SETUP       -- P: ev.waitq.lock
 158          *               happens only in ep0 i/o  which is P: mutex
 159          * + FFS_SETUP_PENDING  -> FFS_SETUP_CANCELED -- P: ev.waitq.lock
 160          * + FFS_SETUP_CANCELED -> FFS_NO_SETUP       -- cmpxchg
 161          */
 162         enum ffs_setup_state            setup_state;
 163
 164 #define FFS_SETUP_STATE(ffs)                                    \
 165         ((enum ffs_setup_state)cmpxchg(&(ffs)->setup_state,     \
 166                                        FFS_SETUP_CANCELED, FFS_NO_SETUP))
 167
 168         /* Events & such. */
 169         struct {
 170                 u8                              types[4];
 171                 unsigned short                  count;
 172                 /* XXX REVISIT need to update it in some places, or do we? */
 173                 unsigned short                  can_stall;
 174                 struct usb_ctrlrequest          setup;
 175
 176                 wait_queue_head_t               waitq;
 177         } ev; /* the whole structure, P: ev.waitq.lock */
 178
 179         /* Flags */
 180         unsigned long                   flags;
 181 #define FFS_FL_CALL_CLOSED_CALLBACK 0
 182 #define FFS_FL_BOUND                1
 183
 184         /* Active function */
 185         struct ffs_function             *func;
 186
 187         /*
 188          * Device name, write once when file system is mounted.
 189          * Intended for user to read if she wants.
 190          */
 191         const char                      *dev_name;
 192         /* Private data for our user (ie. gadget).  Managed by user. */
 193         void                            *private_data;
 194
 195         /* filled by __ffs_data_got_descs() */
 196         /*
 197          * Real descriptors are 16 bytes after raw_descs (so you need
 198          * to skip 16 bytes (ie. ffs->raw_descs + 16) to get to the
 199          * first full speed descriptor).  raw_descs_length and
 200          * raw_fs_descs_length do not have those 16 bytes added.
 201          */
 202         const void                      *raw_descs;
 203         unsigned                        raw_descs_length;
 204         unsigned                        raw_fs_descs_length;
 205         unsigned                        fs_descs_count;
 206         unsigned                        hs_descs_count;
 207
 208         unsigned short                  strings_count;
 209         unsigned short                  interfaces_count;
 210         unsigned short                  eps_count;
 211         unsigned short                  _pad1;
 212
 213         /* filled by __ffs_data_got_strings() */
 214         /* ids in stringtabs are set in functionfs_bind() */
 215         const void                      *raw_strings;
 216         struct usb_gadget_strings       **stringtabs;
 217
 218         /*
 219          * File system's super block, write once when file system is
 220          * mounted.
 221          */
 222         struct super_block              *sb;
 223
 224         /* File permissions, written once when fs is mounted */
 225         struct ffs_file_perms {
 226                 umode_t                         mode;
 227                 uid_t                           uid;
 228                 gid_t                           gid;
 229         }                               file_perms;
 230
 231         /*
 232          * The endpoint files, filled by ffs_epfiles_create(),
 233          * destroyed by ffs_epfiles_destroy().
 234          */
 235         struct ffs_epfile               *epfiles;
 236 };
 237
 238 /* Reference counter handling */
 239 static void ffs_data_get(struct ffs_data *ffs);
 240 static void ffs_data_put(struct ffs_data *ffs);
 241 /* Creates new ffs_data object. */
 242 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
 243
 244 /* Opened counter handling. */
 245 static void ffs_data_opened(struct ffs_data *ffs);
 246 static void ffs_data_closed(struct ffs_data *ffs);
 247
 248 /* Called with ffs->mutex held; take over ownership of data. */
 249 static int __must_check
 250 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
 251 static int __must_check
 252 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
 253
 254
 255 /* The function structure ***************************************************/
 256
 257 struct ffs_ep;
 258
 259 struct ffs_function {
 260         struct usb_configuration        *conf;
 261         struct usb_gadget               *gadget;
 262         struct ffs_data                 *ffs;
 263
 264         struct ffs_ep                   *eps;
 265         u8                              eps_revmap[16];
 266         short                           *interfaces_nums;
 267
 268         struct usb_function             function;
 269 };
 270
 271
 272 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
 273 {
 274         return container_of(f, struct ffs_function, function);
 275 }
 276
 277 static void ffs_func_free(struct ffs_function *func);
 278
 279 static void ffs_func_eps_disable(struct ffs_function *func);
 280 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
 281
 282 static int ffs_func_bind(struct usb_configuration *,
 283                          struct usb_function *);
 284 static void ffs_func_unbind(struct usb_configuration *,
 285                             struct usb_function *);
 286 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 287 static void ffs_func_disable(struct usb_function *);
 288 static int ffs_func_setup(struct usb_function *,
 289                           const struct usb_ctrlrequest *);
 290 static void ffs_func_suspend(struct usb_function *);
 291 static void ffs_func_resume(struct usb_function *);
 292
 293
 294 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 295 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 296
 297
 298 /* The endpoints structures *************************************************/
 299
 300 struct ffs_ep {
 301         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 302         struct usb_request              *req;   /* P: epfile->mutex */
 303
 304         /* [0]: full speed, [1]: high speed */
 305         struct usb_endpoint_descriptor  *descs[2];
 306
 307         u8                              num;
 308
 309         int                             status; /* P: epfile->mutex */
 310 };
 311
 312 struct ffs_epfile {
 313         /* Protects ep->ep and ep->req. */
 314         struct mutex                    mutex;
 315         wait_queue_head_t               wait;
 316
 317         struct ffs_data                 *ffs;
 318         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 319
 320         struct dentry                   *dentry;
 321
 322         char                            name[5];
 323
 324         unsigned char                   in;     /* P: ffs->eps_lock */
 325         unsigned char                   isoc;   /* P: ffs->eps_lock */
 326
 327         unsigned char                   _pad;
 328 };
 329
 330 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 331 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 332
 333 static struct inode *__must_check
 334 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 335                    const struct file_operations *fops,
 336                    struct dentry **dentry_p);
 337
 338
 339 /* Misc helper functions ****************************************************/
 340
 341 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 342         __attribute__((warn_unused_result, nonnull));
 343 static char *ffs_prepare_buffer(const char * __user buf, size_t len)
 344         __attribute__((warn_unused_result, nonnull));
 345
 346
 347 /* Control file aka ep0 *****************************************************/
 348
 349 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 350 {
 351         struct ffs_data *ffs = req->context;
 352
 353         complete_all(&ffs->ep0req_completion);
 354 }
 355
 356 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 357 {
 358         struct usb_request *req = ffs->ep0req;
 359         int ret;
 360
 361         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 362
 363         spin_unlock_irq(&ffs->ev.waitq.lock);
 364
 365         req->buf      = data;
 366         req->length   = len;
 367
 368         /*
 369          * UDC layer requires to provide a buffer even for ZLP, but should
 370          * not use it at all. Let's provide some poisoned pointer to catch
 371          * possible bug in the driver.
 372          */
 373         if (req->buf == NULL)
 374                 req->buf = (void *)0xDEADBABE;
 375
 376         INIT_COMPLETION(ffs->ep0req_completion);
 377
 378         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 379         if (unlikely(ret < 0))
 380                 return ret;
 381
 382         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 383         if (unlikely(ret)) {
 384                 usb_ep_dequeue(ffs->gadget->ep0, req);
 385                 return -EINTR;
 386         }
 387
 388         ffs->setup_state = FFS_NO_SETUP;
 389         return ffs->ep0req_status;
 390 }
 391
 392 static int __ffs_ep0_stall(struct ffs_data *ffs)
 393 {
 394         if (ffs->ev.can_stall) {
 395                 pr_vdebug("ep0 stall\n");
 396                 usb_ep_set_halt(ffs->gadget->ep0);
 397                 ffs->setup_state = FFS_NO_SETUP;
 398                 return -EL2HLT;
 399         } else {
 400                 pr_debug("bogus ep0 stall!\n");
 401                 return -ESRCH;
 402         }
 403 }
 404
 405 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 406                              size_t len, loff_t *ptr)
 407 {
 408         struct ffs_data *ffs = file->private_data;
 409         ssize_t ret;
 410         char *data;
 411
 412         ENTER();
 413
 414         /* Fast check if setup was canceled */
 415         if (FFS_SETUP_STATE(ffs) == FFS_SETUP_CANCELED)
 416                 return -EIDRM;
 417
 418         /* Acquire mutex */
 419         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 420         if (unlikely(ret < 0))
 421                 return ret;
 422
 423         /* Check state */
 424         switch (ffs->state) {
 425         case FFS_READ_DESCRIPTORS:
 426         case FFS_READ_STRINGS:
 427                 /* Copy data */
 428                 if (unlikely(len < 16)) {
 429                         ret = -EINVAL;
 430                         break;
 431                 }
 432
 433                 data = ffs_prepare_buffer(buf, len);
 434                 if (IS_ERR(data)) {
 435                         ret = PTR_ERR(data);
 436                         break;
 437                 }
 438
 439                 /* Handle data */
 440                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 441                         pr_info("read descriptors\n");
 442                         ret = __ffs_data_got_descs(ffs, data, len);
 443                         if (unlikely(ret < 0))
 444                                 break;
 445
 446                         ffs->state = FFS_READ_STRINGS;
 447                         ret = len;
 448                 } else {
 449                         pr_info("read strings\n");
 450                         ret = __ffs_data_got_strings(ffs, data, len);
 451                         if (unlikely(ret < 0))
 452                                 break;
 453
 454                         ret = ffs_epfiles_create(ffs);
 455                         if (unlikely(ret)) {
 456                                 ffs->state = FFS_CLOSING;
 457                                 break;
 458                         }
 459
 460                         ffs->state = FFS_ACTIVE;
 461                         mutex_unlock(&ffs->mutex);
 462
 463                         ret = functionfs_ready_callback(ffs);
 464                         if (unlikely(ret < 0)) {
 465                                 ffs->state = FFS_CLOSING;
 466                                 return ret;
 467                         }
 468
 469                         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
 470                         return len;
 471                 }
 472                 break;
 473
 474         case FFS_ACTIVE:
 475                 data = NULL;
 476                 /*
 477                  * We're called from user space, we can use _irq
 478                  * rather then _irqsave
 479                  */
 480                 spin_lock_irq(&ffs->ev.waitq.lock);
 481                 switch (FFS_SETUP_STATE(ffs)) {
 482                 case FFS_SETUP_CANCELED:
 483                         ret = -EIDRM;
 484                         goto done_spin;
 485
 486                 case FFS_NO_SETUP:
 487                         ret = -ESRCH;
 488                         goto done_spin;
 489
 490                 case FFS_SETUP_PENDING:
 491                         break;
 492                 }
 493
 494                 /* FFS_SETUP_PENDING */
 495                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 496                         spin_unlock_irq(&ffs->ev.waitq.lock);
 497                         ret = __ffs_ep0_stall(ffs);
 498                         break;
 499                 }
 500
 501                 /* FFS_SETUP_PENDING and not stall */
 502                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 503
 504                 spin_unlock_irq(&ffs->ev.waitq.lock);
 505
 506                 data = ffs_prepare_buffer(buf, len);
 507                 if (IS_ERR(data)) {
 508                         ret = PTR_ERR(data);
 509                         break;
 510                 }
 511
 512                 spin_lock_irq(&ffs->ev.waitq.lock);
 513
 514                 /*
 515                  * We are guaranteed to be still in FFS_ACTIVE state
 516                  * but the state of setup could have changed from
 517                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELED so we need
 518                  * to check for that.  If that happened we copied data
 519                  * from user space in vain but it's unlikely.
 520                  *
 521                  * For sure we are not in FFS_NO_SETUP since this is
 522                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 523                  * transition can be performed and it's protected by
 524                  * mutex.
 525                  */
 526                 if (FFS_SETUP_STATE(ffs) == FFS_SETUP_CANCELED) {
 527                         ret = -EIDRM;
 528 done_spin:
 529                         spin_unlock_irq(&ffs->ev.waitq.lock);
 530                 } else {
 531                         /* unlocks spinlock */
 532                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 533                 }
 534                 kfree(data);
 535                 break;
 536
 537         default:
 538                 ret = -EBADFD;
 539                 break;
 540         }
 541
 542         mutex_unlock(&ffs->mutex);
 543         return ret;
 544 }
 545
 546 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 547                                      size_t n)
 548 {
 549         /*
 550          * We are holding ffs->ev.waitq.lock and ffs->mutex and we need
 551          * to release them.
 552          */
 553         struct usb_functionfs_event events[n];
 554         unsigned i = 0;
 555
 556         memset(events, 0, sizeof events);
 557
 558         do {
 559                 events[i].type = ffs->ev.types[i];
 560                 if (events[i].type == FUNCTIONFS_SETUP) {
 561                         events[i].u.setup = ffs->ev.setup;
 562                         ffs->setup_state = FFS_SETUP_PENDING;
 563                 }
 564         } while (++i < n);
 565
 566         if (n < ffs->ev.count) {
 567                 ffs->ev.count -= n;
 568                 memmove(ffs->ev.types, ffs->ev.types + n,
 569                         ffs->ev.count * sizeof *ffs->ev.types);
 570         } else {
 571                 ffs->ev.count = 0;
 572         }
 573
 574         spin_unlock_irq(&ffs->ev.waitq.lock);
 575         mutex_unlock(&ffs->mutex);
 576
 577         return unlikely(__copy_to_user(buf, events, sizeof events))
 578                 ? -EFAULT : sizeof events;
 579 }
 580
 581 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 582                             size_t len, loff_t *ptr)
 583 {
 584         struct ffs_data *ffs = file->private_data;
 585         char *data = NULL;
 586         size_t n;
 587         int ret;
 588
 589         ENTER();
 590
 591         /* Fast check if setup was canceled */
 592         if (FFS_SETUP_STATE(ffs) == FFS_SETUP_CANCELED)
 593                 return -EIDRM;
 594
 595         /* Acquire mutex */
 596         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 597         if (unlikely(ret < 0))
 598                 return ret;
 599
 600         /* Check state */
 601         if (ffs->state != FFS_ACTIVE) {
 602                 ret = -EBADFD;
 603                 goto done_mutex;
 604         }
 605
 606         /*
 607          * We're called from user space, we can use _irq rather then
 608          * _irqsave
 609          */
 610         spin_lock_irq(&ffs->ev.waitq.lock);
 611
 612         switch (FFS_SETUP_STATE(ffs)) {
 613         case FFS_SETUP_CANCELED:
 614                 ret = -EIDRM;
 615                 break;
 616
 617         case FFS_NO_SETUP:
 618                 n = len / sizeof(struct usb_functionfs_event);
 619                 if (unlikely(!n)) {
 620                         ret = -EINVAL;
 621                         break;
 622                 }
 623
 624                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 625                         ret = -EAGAIN;
 626                         break;
 627                 }
 628
 629                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 630                                                         ffs->ev.count)) {
 631                         ret = -EINTR;
 632                         break;
 633                 }
 634
 635                 return __ffs_ep0_read_events(ffs, buf,
 636                                              min(n, (size_t)ffs->ev.count));
 637
 638         case FFS_SETUP_PENDING:
 639                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 640                         spin_unlock_irq(&ffs->ev.waitq.lock);
 641                         ret = __ffs_ep0_stall(ffs);
 642                         goto done_mutex;
 643                 }
 644
 645                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 646
 647                 spin_unlock_irq(&ffs->ev.waitq.lock);
 648
 649                 if (likely(len)) {
 650                         data = kmalloc(len, GFP_KERNEL);
 651                         if (unlikely(!data)) {
 652                                 ret = -ENOMEM;
 653                                 goto done_mutex;
 654                         }
 655                 }
 656
 657                 spin_lock_irq(&ffs->ev.waitq.lock);
 658
 659                 /* See ffs_ep0_write() */
 660                 if (FFS_SETUP_STATE(ffs) == FFS_SETUP_CANCELED) {
 661                         ret = -EIDRM;
 662                         break;
 663                 }
 664
 665                 /* unlocks spinlock */
 666                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 667                 if (likely(ret > 0) && unlikely(__copy_to_user(buf, data, len)))
 668                         ret = -EFAULT;
 669                 goto done_mutex;
 670
 671         default:
 672                 ret = -EBADFD;
 673                 break;
 674         }
 675
 676         spin_unlock_irq(&ffs->ev.waitq.lock);
 677 done_mutex:
 678         mutex_unlock(&ffs->mutex);
 679         kfree(data);
 680         return ret;
 681 }
 682
 683 static int ffs_ep0_open(struct inode *inode, struct file *file)
 684 {
 685         struct ffs_data *ffs = inode->i_private;
 686
 687         ENTER();
 688
 689         if (unlikely(ffs->state == FFS_CLOSING))
 690                 return -EBUSY;
 691
 692         file->private_data = ffs;
 693         ffs_data_opened(ffs);
 694
 695         return 0;
 696 }
 697
 698 static int ffs_ep0_release(struct inode *inode, struct file *file)
 699 {
 700         struct ffs_data *ffs = file->private_data;
 701
 702         ENTER();
 703
 704         ffs_data_closed(ffs);
 705
 706         return 0;
 707 }
 708
 709 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 710 {
 711         struct ffs_data *ffs = file->private_data;
 712         struct usb_gadget *gadget = ffs->gadget;
 713         long ret;
 714
 715         ENTER();
 716
 717         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 718                 struct ffs_function *func = ffs->func;
 719                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 720         } else if (gadget && gadget->ops->ioctl) {
 721                 ret = gadget->ops->ioctl(gadget, code, value);
 722         } else {
 723                 ret = -ENOTTY;
 724         }
 725
 726         return ret;
 727 }
 728
 729 static const struct file_operations ffs_ep0_operations = {
 730         .owner =        THIS_MODULE,
 731         .llseek =       no_llseek,
 732
 733         .open =         ffs_ep0_open,
 734         .write =        ffs_ep0_write,
 735         .read =         ffs_ep0_read,
 736         .release =      ffs_ep0_release,
 737         .unlocked_ioctl =       ffs_ep0_ioctl,
 738 };
 739
 740
 741 /* "Normal" endpoints operations ********************************************/
 742
 743 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 744 {
 745         ENTER();
 746         if (likely(req->context)) {
 747                 struct ffs_ep *ep = _ep->driver_data;
 748                 ep->status = req->status ? req->status : req->actual;
 749                 complete(req->context);
 750         }
 751 }
 752
 753 static ssize_t ffs_epfile_io(struct file *file,
 754                              char __user *buf, size_t len, int read)
 755 {
 756         struct ffs_epfile *epfile = file->private_data;
 757         struct ffs_ep *ep;
 758         char *data = NULL;
 759         ssize_t ret;
 760         int halt;
 761
 762         goto first_try;
 763         do {
 764                 spin_unlock_irq(&epfile->ffs->eps_lock);
 765                 mutex_unlock(&epfile->mutex);
 766
 767 first_try:
 768                 /* Are we still active? */
 769                 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
 770                         ret = -ENODEV;
 771                         goto error;
 772                 }
 773
 774                 /* Wait for endpoint to be enabled */
 775                 ep = epfile->ep;
 776                 if (!ep) {
 777                         if (file->f_flags & O_NONBLOCK) {
 778                                 ret = -EAGAIN;
 779                                 goto error;
 780                         }
 781
 782                         if (wait_event_interruptible(epfile->wait,
 783                                                      (ep = epfile->ep))) {
 784                                 ret = -EINTR;
 785                                 goto error;
 786                         }
 787                 }
 788
 789                 /* Do we halt? */
 790                 halt = !read == !epfile->in;
 791                 if (halt && epfile->isoc) {
 792                         ret = -EINVAL;
 793                         goto error;
 794                 }
 795
 796                 /* Allocate & copy */
 797                 if (!halt && !data) {
 798                         data = kzalloc(len, GFP_KERNEL);
 799                         if (unlikely(!data))
 800                                 return -ENOMEM;
 801
 802                         if (!read &&
 803                             unlikely(__copy_from_user(data, buf, len))) {
 804                                 ret = -EFAULT;
 805                                 goto error;
 806                         }
 807                 }
 808
 809                 /* We will be using request */
 810                 ret = ffs_mutex_lock(&epfile->mutex,
 811                                      file->f_flags & O_NONBLOCK);
 812                 if (unlikely(ret))
 813                         goto error;
 814
 815                 /*
 816                  * We're called from user space, we can use _irq rather then
 817                  * _irqsave
 818                  */
 819                 spin_lock_irq(&epfile->ffs->eps_lock);
 820
 821                 /*
 822                  * While we were acquiring mutex endpoint got disabled
 823                  * or changed?
 824                  */
 825         } while (unlikely(epfile->ep != ep));
 826
 827         /* Halt */
 828         if (unlikely(halt)) {
 829                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 830                         usb_ep_set_halt(ep->ep);
 831                 spin_unlock_irq(&epfile->ffs->eps_lock);
 832                 ret = -EBADMSG;
 833         } else {
 834                 /* Fire the request */
 835                 DECLARE_COMPLETION_ONSTACK(done);
 836
 837                 struct usb_request *req = ep->req;
 838                 req->context  = &done;
 839                 req->complete = ffs_epfile_io_complete;
 840                 req->buf      = data;
 841                 req->length   = len;
 842
 843                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 844
 845                 spin_unlock_irq(&epfile->ffs->eps_lock);
 846
 847                 if (unlikely(ret < 0)) {
 848                         /* nop */
 849                 } else if (unlikely(wait_for_completion_interruptible(&done))) {
 850                         ret = -EINTR;
 851                         usb_ep_dequeue(ep->ep, req);
 852                 } else {
 853                         ret = ep->status;
 854                         if (read && ret > 0 &&
 855                             unlikely(copy_to_user(buf, data, ret)))
 856                                 ret = -EFAULT;
 857                 }
 858         }
 859
 860         mutex_unlock(&epfile->mutex);
 861 error:
 862         kfree(data);
 863         return ret;
 864 }
 865
 866 static ssize_t
 867 ffs_epfile_write(struct file *file, const char __user *buf, size_t len,
 868                  loff_t *ptr)
 869 {
 870         ENTER();
 871
 872         return ffs_epfile_io(file, (char __user *)buf, len, 0);
 873 }
 874
 875 static ssize_t
 876 ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr)
 877 {
 878         ENTER();
 879
 880         return ffs_epfile_io(file, buf, len, 1);
 881 }
 882
 883 static int
 884 ffs_epfile_open(struct inode *inode, struct file *file)
 885 {
 886         struct ffs_epfile *epfile = inode->i_private;
 887
 888         ENTER();
 889
 890         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 891                 return -ENODEV;
 892
 893         file->private_data = epfile;
 894         ffs_data_opened(epfile->ffs);
 895
 896         return 0;
 897 }
 898
 899 static int
 900 ffs_epfile_release(struct inode *inode, struct file *file)
 901 {
 902         struct ffs_epfile *epfile = inode->i_private;
 903
 904         ENTER();
 905
 906         ffs_data_closed(epfile->ffs);
 907
 908         return 0;
 909 }
 910
 911 static long ffs_epfile_ioctl(struct file *file, unsigned code,
 912                              unsigned long value)
 913 {
 914         struct ffs_epfile *epfile = file->private_data;
 915         int ret;
 916
 917         ENTER();
 918
 919         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 920                 return -ENODEV;
 921
 922         spin_lock_irq(&epfile->ffs->eps_lock);
 923         if (likely(epfile->ep)) {
 924                 switch (code) {
 925                 case FUNCTIONFS_FIFO_STATUS:
 926                         ret = usb_ep_fifo_status(epfile->ep->ep);
 927                         break;
 928                 case FUNCTIONFS_FIFO_FLUSH:
 929                         usb_ep_fifo_flush(epfile->ep->ep);
 930                         ret = 0;
 931                         break;
 932                 case FUNCTIONFS_CLEAR_HALT:
 933                         ret = usb_ep_clear_halt(epfile->ep->ep);
 934                         break;
 935                 case FUNCTIONFS_ENDPOINT_REVMAP:
 936                         ret = epfile->ep->num;
 937                         break;
 938                 default:
 939                         ret = -ENOTTY;
 940                 }
 941         } else {
 942                 ret = -ENODEV;
 943         }
 944         spin_unlock_irq(&epfile->ffs->eps_lock);
 945
 946         return ret;
 947 }
 948
 949 static const struct file_operations ffs_epfile_operations = {
 950         .owner =        THIS_MODULE,
 951         .llseek =       no_llseek,
 952
 953         .open =         ffs_epfile_open,
 954         .write =        ffs_epfile_write,
 955         .read =         ffs_epfile_read,
 956         .release =      ffs_epfile_release,
 957         .unlocked_ioctl =       ffs_epfile_ioctl,
 958 };
 959
 960
 961 /* File system and super block operations ***********************************/
 962
 963 /*
 964  * Mounting the file system creates a controller file, used first for
 965  * function configuration then later for event monitoring.
 966  */
 967
 968 static struct inode *__must_check
 969 ffs_sb_make_inode(struct super_block *sb, void *data,
 970                   const struct file_operations *fops,
 971                   const struct inode_operations *iops,
 972                   struct ffs_file_perms *perms)
 973 {
 974         struct inode *inode;
 975
 976         ENTER();
 977
 978         inode = new_inode(sb);
 979
 980         if (likely(inode)) {
 981                 struct timespec current_time = CURRENT_TIME;
 982
 983                 inode->i_ino     = get_next_ino();
 984                 inode->i_mode    = perms->mode;
 985                 inode->i_uid     = perms->uid;
 986                 inode->i_gid     = perms->gid;
 987                 inode->i_atime   = current_time;
 988                 inode->i_mtime   = current_time;
 989                 inode->i_ctime   = current_time;
 990                 inode->i_private = data;
 991                 if (fops)
 992                         inode->i_fop = fops;
 993                 if (iops)
 994                         inode->i_op  = iops;
 995         }
 996
 997         return inode;
 998 }
 999
1000 /* Create "regular" file */
1001 static struct inode *ffs_sb_create_file(struct super_block *sb,
1002                                         const char *name, void *data,
1003                                         const struct file_operations *fops,
1004                                         struct dentry **dentry_p)
1005 {
1006         struct ffs_data *ffs = sb->s_fs_info;
1007         struct dentry   *dentry;
1008         struct inode    *inode;
1009
1010         ENTER();
1011
1012         dentry = d_alloc_name(sb->s_root, name);
1013         if (unlikely(!dentry))
1014                 return NULL;
1015
1016         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1017         if (unlikely(!inode)) {
1018                 dput(dentry);
1019                 return NULL;
1020         }
1021
1022         d_add(dentry, inode);
1023         if (dentry_p)
1024                 *dentry_p = dentry;
1025
1026         return inode;
1027 }
1028
1029 /* Super block */
1030 static const struct super_operations ffs_sb_operations = {
1031         .statfs =       simple_statfs,
1032         .drop_inode =   generic_delete_inode,
1033 };
1034
1035 struct ffs_sb_fill_data {
1036         struct ffs_file_perms perms;
1037         umode_t root_mode;
1038         const char *dev_name;
1039         union {
1040                 /* set by ffs_fs_mount(), read by ffs_sb_fill() */
1041                 void *private_data;
1042                 /* set by ffs_sb_fill(), read by ffs_fs_mount */
1043                 struct ffs_data *ffs_data;
1044         };
1045 };
1046
1047 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1048 {
1049         struct ffs_sb_fill_data *data = _data;
1050         struct inode    *inode;
1051         struct ffs_data *ffs;
1052
1053         ENTER();
1054
1055         /* Initialise data */
1056         ffs = ffs_data_new();
1057         if (unlikely(!ffs))
1058                 goto Enomem;
1059
1060         ffs->sb              = sb;
1061         ffs->dev_name        = kstrdup(data->dev_name, GFP_KERNEL);
1062         if (unlikely(!ffs->dev_name))
1063                 goto Enomem;
1064         ffs->file_perms      = data->perms;
1065         ffs->private_data    = data->private_data;
1066
1067         /* used by the caller of this function */
1068         data->ffs_data       = ffs;
1069
1070         sb->s_fs_info        = ffs;
1071         sb->s_blocksize      = PAGE_CACHE_SIZE;
1072         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1073         sb->s_magic          = FUNCTIONFS_MAGIC;
1074         sb->s_op             = &ffs_sb_operations;
1075         sb->s_time_gran      = 1;
1076
1077         /* Root inode */
1078         data->perms.mode = data->root_mode;
1079         inode = ffs_sb_make_inode(sb, NULL,
1080                                   &simple_dir_operations,
1081                                   &simple_dir_inode_operations,
1082                                   &data->perms);
1083         sb->s_root = d_make_root(inode);
1084         if (unlikely(!sb->s_root))
1085                 goto Enomem;
1086
1087         /* EP0 file */
1088         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1089                                          &ffs_ep0_operations, NULL)))
1090                 goto Enomem;
1091
1092         return 0;
1093
1094 Enomem:
1095         return -ENOMEM;
1096 }
1097
1098 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1099 {
1100         ENTER();
1101
1102         if (!opts || !*opts)
1103                 return 0;
1104
1105         for (;;) {
1106                 char *end, *eq, *comma;
1107                 unsigned long value;
1108
1109                 /* Option limit */
1110                 comma = strchr(opts, ',');
1111                 if (comma)
1112                         *comma = 0;
1113
1114                 /* Value limit */
1115                 eq = strchr(opts, '=');
1116                 if (unlikely(!eq)) {
1117                         pr_err("'=' missing in %s\n", opts);
1118                         return -EINVAL;
1119                 }
1120                 *eq = 0;
1121
1122                 /* Parse value */
1123                 value = simple_strtoul(eq + 1, &end, 0);
1124                 if (unlikely(*end != ',' && *end != 0)) {
1125                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1126                         return -EINVAL;
1127                 }
1128
1129                 /* Interpret option */
1130                 switch (eq - opts) {
1131                 case 5:
1132                         if (!memcmp(opts, "rmode", 5))
1133                                 data->root_mode  = (value & 0555) | S_IFDIR;
1134                         else if (!memcmp(opts, "fmode", 5))
1135                                 data->perms.mode = (value & 0666) | S_IFREG;
1136                         else
1137                                 goto invalid;
1138                         break;
1139
1140                 case 4:
1141                         if (!memcmp(opts, "mode", 4)) {
1142                                 data->root_mode  = (value & 0555) | S_IFDIR;
1143                                 data->perms.mode = (value & 0666) | S_IFREG;
1144                         } else {
1145                                 goto invalid;
1146                         }
1147                         break;
1148
1149                 case 3:
1150                         if (!memcmp(opts, "uid", 3))
1151                                 data->perms.uid = value;
1152                         else if (!memcmp(opts, "gid", 3))
1153                                 data->perms.gid = value;
1154                         else
1155                                 goto invalid;
1156                         break;
1157
1158                 default:
1159 invalid:
1160                         pr_err("%s: invalid option\n", opts);
1161                         return -EINVAL;
1162                 }
1163
1164                 /* Next iteration */
1165                 if (!comma)
1166                         break;
1167                 opts = comma + 1;
1168         }
1169
1170         return 0;
1171 }
1172
1173 /* "mount -t functionfs dev_name /dev/function" ends up here */
1174
1175 static struct dentry *
1176 ffs_fs_mount(struct file_system_type *t, int flags,
1177               const char *dev_name, void *opts)
1178 {
1179         struct ffs_sb_fill_data data = {
1180                 .perms = {
1181                         .mode = S_IFREG | 0600,
1182                         .uid = 0,
1183                         .gid = 0
1184                 },
1185                 .root_mode = S_IFDIR | 0500,
1186         };
1187         struct dentry *rv;
1188         int ret;
1189         void *ffs_dev;
1190
1191         ENTER();
1192
1193         ret = ffs_fs_parse_opts(&data, opts);
1194         if (unlikely(ret < 0))
1195                 return ERR_PTR(ret);
1196
1197         ffs_dev = functionfs_acquire_dev_callback(dev_name);
1198         if (IS_ERR(ffs_dev))
1199                 return ffs_dev;
1200
1201         data.dev_name = dev_name;
1202         data.private_data = ffs_dev;
1203         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1204
1205         /* data.ffs_data is set by ffs_sb_fill */
1206         if (IS_ERR(rv))
1207                 functionfs_release_dev_callback(data.ffs_data);
1208
1209         return rv;
1210 }
1211
1212 static void
1213 ffs_fs_kill_sb(struct super_block *sb)
1214 {
1215         ENTER();
1216
1217         kill_litter_super(sb);
1218         if (sb->s_fs_info) {
1219                 functionfs_release_dev_callback(sb->s_fs_info);
1220                 ffs_data_put(sb->s_fs_info);
1221         }
1222 }
1223
1224 static struct file_system_type ffs_fs_type = {
1225         .owner          = THIS_MODULE,
1226         .name           = "functionfs",
1227         .mount          = ffs_fs_mount,
1228         .kill_sb        = ffs_fs_kill_sb,
1229 };
1230
1231
1232 /* Driver's main init/cleanup functions *************************************/
1233
1234 static int functionfs_init(void)
1235 {
1236         int ret;
1237
1238         ENTER();
1239
1240         ret = register_filesystem(&ffs_fs_type);
1241         if (likely(!ret))
1242                 pr_info("file system registered\n");
1243         else
1244                 pr_err("failed registering file system (%d)\n", ret);
1245
1246         return ret;
1247 }
1248
1249 static void functionfs_cleanup(void)
1250 {
1251         ENTER();
1252
1253         pr_info("unloading\n");
1254         unregister_filesystem(&ffs_fs_type);
1255 }
1256
1257
1258 /* ffs_data and ffs_function construction and destruction code **************/
1259
1260 static void ffs_data_clear(struct ffs_data *ffs);
1261 static void ffs_data_reset(struct ffs_data *ffs);
1262
1263 static void ffs_data_get(struct ffs_data *ffs)
1264 {
1265         ENTER();
1266
1267         atomic_inc(&ffs->ref);
1268 }
1269
1270 static void ffs_data_opened(struct ffs_data *ffs)
1271 {
1272         ENTER();
1273
1274         atomic_inc(&ffs->ref);
1275         atomic_inc(&ffs->opened);
1276 }
1277
1278 static void ffs_data_put(struct ffs_data *ffs)
1279 {
1280         ENTER();
1281
1282         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1283                 pr_info("%s(): freeing\n", __func__);
1284                 ffs_data_clear(ffs);
1285                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1286                        waitqueue_active(&ffs->ep0req_completion.wait));
1287                 kfree(ffs->dev_name);
1288                 kfree(ffs);
1289         }
1290 }
1291
1292 static void ffs_data_closed(struct ffs_data *ffs)
1293 {
1294         ENTER();
1295
1296         if (atomic_dec_and_test(&ffs->opened)) {
1297                 ffs->state = FFS_CLOSING;
1298                 ffs_data_reset(ffs);
1299         }
1300
1301         ffs_data_put(ffs);
1302 }
1303
1304 static struct ffs_data *ffs_data_new(void)
1305 {
1306         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1307         if (unlikely(!ffs))
1308                 return 0;
1309
1310         ENTER();
1311
1312         atomic_set(&ffs->ref, 1);
1313         atomic_set(&ffs->opened, 0);
1314         ffs->state = FFS_READ_DESCRIPTORS;
1315         mutex_init(&ffs->mutex);
1316         spin_lock_init(&ffs->eps_lock);
1317         init_waitqueue_head(&ffs->ev.waitq);
1318         init_completion(&ffs->ep0req_completion);
1319
1320         /* XXX REVISIT need to update it in some places, or do we? */
1321         ffs->ev.can_stall = 1;
1322
1323         return ffs;
1324 }
1325
1326 static void ffs_data_clear(struct ffs_data *ffs)
1327 {
1328         ENTER();
1329
1330         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags))
1331                 functionfs_closed_callback(ffs);
1332
1333         BUG_ON(ffs->gadget);
1334
1335         if (ffs->epfiles)
1336                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1337
1338         kfree(ffs->raw_descs);
1339         kfree(ffs->raw_strings);
1340         kfree(ffs->stringtabs);
1341 }
1342
1343 static void ffs_data_reset(struct ffs_data *ffs)
1344 {
1345         ENTER();
1346
1347         ffs_data_clear(ffs);
1348
1349         ffs->epfiles = NULL;
1350         ffs->raw_descs = NULL;
1351         ffs->raw_strings = NULL;
1352         ffs->stringtabs = NULL;
1353
1354         ffs->raw_descs_length = 0;
1355         ffs->raw_fs_descs_length = 0;
1356         ffs->fs_descs_count = 0;
1357         ffs->hs_descs_count = 0;
1358
1359         ffs->strings_count = 0;
1360         ffs->interfaces_count = 0;
1361         ffs->eps_count = 0;
1362
1363         ffs->ev.count = 0;
1364
1365         ffs->state = FFS_READ_DESCRIPTORS;
1366         ffs->setup_state = FFS_NO_SETUP;
1367         ffs->flags = 0;
1368 }
1369
1370
1371 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1372 {
1373         struct usb_gadget_strings **lang;
1374         int first_id;
1375
1376         ENTER();
1377
1378         if (WARN_ON(ffs->state != FFS_ACTIVE
1379                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1380                 return -EBADFD;
1381
1382         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1383         if (unlikely(first_id < 0))
1384                 return first_id;
1385
1386         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1387         if (unlikely(!ffs->ep0req))
1388                 return -ENOMEM;
1389         ffs->ep0req->complete = ffs_ep0_complete;
1390         ffs->ep0req->context = ffs;
1391
1392         lang = ffs->stringtabs;
1393         for (lang = ffs->stringtabs; *lang; ++lang) {
1394                 struct usb_string *str = (*lang)->strings;
1395                 int id = first_id;
1396                 for (; str->s; ++id, ++str)
1397                         str->id = id;
1398         }
1399
1400         ffs->gadget = cdev->gadget;
1401         ffs_data_get(ffs);
1402         return 0;
1403 }
1404
1405 static void functionfs_unbind(struct ffs_data *ffs)
1406 {
1407         ENTER();
1408
1409         if (!WARN_ON(!ffs->gadget)) {
1410                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1411                 ffs->ep0req = NULL;
1412                 ffs->gadget = NULL;
1413                 ffs_data_put(ffs);
1414                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1415         }
1416 }
1417
1418 static int ffs_epfiles_create(struct ffs_data *ffs)
1419 {
1420         struct ffs_epfile *epfile, *epfiles;
1421         unsigned i, count;
1422
1423         ENTER();
1424
1425         count = ffs->eps_count;
1426         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1427         if (!epfiles)
1428                 return -ENOMEM;
1429
1430         epfile = epfiles;
1431         for (i = 1; i <= count; ++i, ++epfile) {
1432                 epfile->ffs = ffs;
1433                 mutex_init(&epfile->mutex);
1434                 init_waitqueue_head(&epfile->wait);
1435                 sprintf(epfiles->name, "ep%u",  i);
1436                 if (!unlikely(ffs_sb_create_file(ffs->sb, epfiles->name, epfile,
1437                                                  &ffs_epfile_operations,
1438                                                  &epfile->dentry))) {
1439                         ffs_epfiles_destroy(epfiles, i - 1);
1440                         return -ENOMEM;
1441                 }
1442         }
1443
1444         ffs->epfiles = epfiles;
1445         return 0;
1446 }
1447
1448 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1449 {
1450         struct ffs_epfile *epfile = epfiles;
1451
1452         ENTER();
1453
1454         for (; count; --count, ++epfile) {
1455                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1456                        waitqueue_active(&epfile->wait));
1457                 if (epfile->dentry) {
1458                         d_delete(epfile->dentry);
1459                         dput(epfile->dentry);
1460                         epfile->dentry = NULL;
1461                 }
1462         }
1463
1464         kfree(epfiles);
1465 }
1466
1467 static int functionfs_bind_config(struct usb_composite_dev *cdev,
1468                                   struct usb_configuration *c,
1469                                   struct ffs_data *ffs)
1470 {
1471         struct ffs_function *func;
1472         int ret;
1473
1474         ENTER();
1475
1476         func = kzalloc(sizeof *func, GFP_KERNEL);
1477         if (unlikely(!func))
1478                 return -ENOMEM;
1479
1480         func->function.name    = "Function FS Gadget";
1481         func->function.strings = ffs->stringtabs;
1482
1483         func->function.bind    = ffs_func_bind;
1484         func->function.unbind  = ffs_func_unbind;
1485         func->function.set_alt = ffs_func_set_alt;
1486         func->function.disable = ffs_func_disable;
1487         func->function.setup   = ffs_func_setup;
1488         func->function.suspend = ffs_func_suspend;
1489         func->function.resume  = ffs_func_resume;
1490
1491         func->conf   = c;
1492         func->gadget = cdev->gadget;
1493         func->ffs = ffs;
1494         ffs_data_get(ffs);
1495
1496         ret = usb_add_function(c, &func->function);
1497         if (unlikely(ret))
1498                 ffs_func_free(func);
1499
1500         return ret;
1501 }
1502
1503 static void ffs_func_free(struct ffs_function *func)
1504 {
1505         struct ffs_ep *ep         = func->eps;
1506         unsigned count            = func->ffs->eps_count;
1507         unsigned long flags;
1508
1509         ENTER();
1510
1511         /* cleanup after autoconfig */
1512         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1513         do {
1514                 if (ep->ep && ep->req)
1515                         usb_ep_free_request(ep->ep, ep->req);
1516                 ep->req = NULL;
1517                 ++ep;
1518         } while (--count);
1519         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1520
1521         ffs_data_put(func->ffs);
1522
1523         kfree(func->eps);
1524         /*
1525          * eps and interfaces_nums are allocated in the same chunk so
1526          * only one free is required.  Descriptors are also allocated
1527          * in the same chunk.
1528          */
1529
1530         kfree(func);
1531 }
1532
1533 static void ffs_func_eps_disable(struct ffs_function *func)
1534 {
1535         struct ffs_ep *ep         = func->eps;
1536         struct ffs_epfile *epfile = func->ffs->epfiles;
1537         unsigned count            = func->ffs->eps_count;
1538         unsigned long flags;
1539
1540         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1541         do {
1542                 /* pending requests get nuked */
1543                 if (likely(ep->ep))
1544                         usb_ep_disable(ep->ep);
1545                 epfile->ep = NULL;
1546
1547                 ++ep;
1548                 ++epfile;
1549         } while (--count);
1550         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1551 }
1552
1553 static int ffs_func_eps_enable(struct ffs_function *func)
1554 {
1555         struct ffs_data *ffs      = func->ffs;
1556         struct ffs_ep *ep         = func->eps;
1557         struct ffs_epfile *epfile = ffs->epfiles;
1558         unsigned count            = ffs->eps_count;
1559         unsigned long flags;
1560         int ret = 0;
1561
1562         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1563         do {
1564                 struct usb_endpoint_descriptor *ds;
1565                 ds = ep->descs[ep->descs[1] ? 1 : 0];
1566
1567                 ep->ep->driver_data = ep;
1568                 ep->ep->desc = ds;
1569                 ret = usb_ep_enable(ep->ep);
1570                 if (likely(!ret)) {
1571                         epfile->ep = ep;
1572                         epfile->in = usb_endpoint_dir_in(ds);
1573                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1574                 } else {
1575                         break;
1576                 }
1577
1578                 wake_up(&epfile->wait);
1579
1580                 ++ep;
1581                 ++epfile;
1582         } while (--count);
1583         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1584
1585         return ret;
1586 }
1587
1588
1589 /* Parsing and building descriptors and strings *****************************/
1590
1591 /*
1592  * This validates if data pointed by data is a valid USB descriptor as
1593  * well as record how many interfaces, endpoints and strings are
1594  * required by given configuration.  Returns address after the
1595  * descriptor or NULL if data is invalid.
1596  */
1597
1598 enum ffs_entity_type {
1599         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1600 };
1601
1602 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1603                                    u8 *valuep,
1604                                    struct usb_descriptor_header *desc,
1605                                    void *priv);
1606
1607 static int __must_check ffs_do_desc(char *data, unsigned len,
1608                                     ffs_entity_callback entity, void *priv)
1609 {
1610         struct usb_descriptor_header *_ds = (void *)data;
1611         u8 length;
1612         int ret;
1613
1614         ENTER();
1615
1616         /* At least two bytes are required: length and type */
1617         if (len < 2) {
1618                 pr_vdebug("descriptor too short\n");
1619                 return -EINVAL;
1620         }
1621
1622         /* If we have at least as many bytes as the descriptor takes? */
1623         length = _ds->bLength;
1624         if (len < length) {
1625                 pr_vdebug("descriptor longer then available data\n");
1626                 return -EINVAL;
1627         }
1628
1629 #define __entity_check_INTERFACE(val)  1
1630 #define __entity_check_STRING(val)     (val)
1631 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1632 #define __entity(type, val) do {                                        \
1633                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1634                 if (unlikely(!__entity_check_ ##type(val))) {           \
1635                         pr_vdebug("invalid entity's value\n");          \
1636                         return -EINVAL;                                 \
1637                 }                                                       \
1638                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1639                 if (unlikely(ret < 0)) {                                \
1640                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1641                                  (val), ret);                           \
1642                         return ret;                                     \
1643                 }                                                       \
1644         } while (0)
1645
1646         /* Parse descriptor depending on type. */
1647         switch (_ds->bDescriptorType) {
1648         case USB_DT_DEVICE:
1649         case USB_DT_CONFIG:
1650         case USB_DT_STRING:
1651         case USB_DT_DEVICE_QUALIFIER:
1652                 /* function can't have any of those */
1653                 pr_vdebug("descriptor reserved for gadget: %d\n",
1654                       _ds->bDescriptorType);
1655                 return -EINVAL;
1656
1657         case USB_DT_INTERFACE: {
1658                 struct usb_interface_descriptor *ds = (void *)_ds;
1659                 pr_vdebug("interface descriptor\n");
1660                 if (length != sizeof *ds)
1661                         goto inv_length;
1662
1663                 __entity(INTERFACE, ds->bInterfaceNumber);
1664                 if (ds->iInterface)
1665                         __entity(STRING, ds->iInterface);
1666         }
1667                 break;
1668
1669         case USB_DT_ENDPOINT: {
1670                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1671                 pr_vdebug("endpoint descriptor\n");
1672                 if (length != USB_DT_ENDPOINT_SIZE &&
1673                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1674                         goto inv_length;
1675                 __entity(ENDPOINT, ds->bEndpointAddress);
1676         }
1677                 break;
1678
1679         case HID_DT_HID:
1680                 pr_vdebug("hid descriptor\n");
1681                 if (length != sizeof(struct hid_descriptor))
1682                         goto inv_length;
1683                 break;
1684
1685         case USB_DT_OTG:
1686                 if (length != sizeof(struct usb_otg_descriptor))
1687                         goto inv_length;
1688                 break;
1689
1690         case USB_DT_INTERFACE_ASSOCIATION: {
1691                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1692                 pr_vdebug("interface association descriptor\n");
1693                 if (length != sizeof *ds)
1694                         goto inv_length;
1695                 if (ds->iFunction)
1696                         __entity(STRING, ds->iFunction);
1697         }
1698                 break;
1699
1700         case USB_DT_OTHER_SPEED_CONFIG:
1701         case USB_DT_INTERFACE_POWER:
1702         case USB_DT_DEBUG:
1703         case USB_DT_SECURITY:
1704         case USB_DT_CS_RADIO_CONTROL:
1705                 /* TODO */
1706                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1707                 return -EINVAL;
1708
1709         default:
1710                 /* We should never be here */
1711                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1712                 return -EINVAL;
1713
1714 inv_length:
1715                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1716                           _ds->bLength, _ds->bDescriptorType);
1717                 return -EINVAL;
1718         }
1719
1720 #undef __entity
1721 #undef __entity_check_DESCRIPTOR
1722 #undef __entity_check_INTERFACE
1723 #undef __entity_check_STRING
1724 #undef __entity_check_ENDPOINT
1725
1726         return length;
1727 }
1728
1729 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1730                                      ffs_entity_callback entity, void *priv)
1731 {
1732         const unsigned _len = len;
1733         unsigned long num = 0;
1734
1735         ENTER();
1736
1737         for (;;) {
1738                 int ret;
1739
1740                 if (num == count)
1741                         data = NULL;
1742
1743                 /* Record "descriptor" entity */
1744                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1745                 if (unlikely(ret < 0)) {
1746                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1747                                  num, ret);
1748                         return ret;
1749                 }
1750
1751                 if (!data)
1752                         return _len - len;
1753
1754                 ret = ffs_do_desc(data, len, entity, priv);
1755                 if (unlikely(ret < 0)) {
1756                         pr_debug("%s returns %d\n", __func__, ret);
1757                         return ret;
1758                 }
1759
1760                 len -= ret;
1761                 data += ret;
1762                 ++num;
1763         }
1764 }
1765
1766 static int __ffs_data_do_entity(enum ffs_entity_type type,
1767                                 u8 *valuep, struct usb_descriptor_header *desc,
1768                                 void *priv)
1769 {
1770         struct ffs_data *ffs = priv;
1771
1772         ENTER();
1773
1774         switch (type) {
1775         case FFS_DESCRIPTOR:
1776                 break;
1777
1778         case FFS_INTERFACE:
1779                 /*
1780                  * Interfaces are indexed from zero so if we
1781                  * encountered interface "n" then there are at least
1782                  * "n+1" interfaces.
1783                  */
1784                 if (*valuep >= ffs->interfaces_count)
1785                         ffs->interfaces_count = *valuep + 1;
1786                 break;
1787
1788         case FFS_STRING:
1789                 /*
1790                  * Strings are indexed from 1 (0 is magic ;) reserved
1791                  * for languages list or some such)
1792                  */
1793                 if (*valuep > ffs->strings_count)
1794                         ffs->strings_count = *valuep;
1795                 break;
1796
1797         case FFS_ENDPOINT:
1798                 /* Endpoints are indexed from 1 as well. */
1799                 if ((*valuep & USB_ENDPOINT_NUMBER_MASK) > ffs->eps_count)
1800                         ffs->eps_count = (*valuep & USB_ENDPOINT_NUMBER_MASK);
1801                 break;
1802         }
1803
1804         return 0;
1805 }
1806
1807 static int __ffs_data_got_descs(struct ffs_data *ffs,
1808                                 char *const _data, size_t len)
1809 {
1810         unsigned fs_count, hs_count;
1811         int fs_len, ret = -EINVAL;
1812         char *data = _data;
1813
1814         ENTER();
1815
1816         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_DESCRIPTORS_MAGIC ||
1817                      get_unaligned_le32(data + 4) != len))
1818                 goto error;
1819         fs_count = get_unaligned_le32(data +  8);
1820         hs_count = get_unaligned_le32(data + 12);
1821
1822         if (!fs_count && !hs_count)
1823                 goto einval;
1824
1825         data += 16;
1826         len  -= 16;
1827
1828         if (likely(fs_count)) {
1829                 fs_len = ffs_do_descs(fs_count, data, len,
1830                                       __ffs_data_do_entity, ffs);
1831                 if (unlikely(fs_len < 0)) {
1832                         ret = fs_len;
1833                         goto error;
1834                 }
1835
1836                 data += fs_len;
1837                 len  -= fs_len;
1838         } else {
1839                 fs_len = 0;
1840         }
1841
1842         if (likely(hs_count)) {
1843                 ret = ffs_do_descs(hs_count, data, len,
1844                                    __ffs_data_do_entity, ffs);
1845                 if (unlikely(ret < 0))
1846                         goto error;
1847         } else {
1848                 ret = 0;
1849         }
1850
1851         if (unlikely(len != ret))
1852                 goto einval;
1853
1854         ffs->raw_fs_descs_length = fs_len;
1855         ffs->raw_descs_length    = fs_len + ret;
1856         ffs->raw_descs           = _data;
1857         ffs->fs_descs_count      = fs_count;
1858         ffs->hs_descs_count      = hs_count;
1859
1860         return 0;
1861
1862 einval:
1863         ret = -EINVAL;
1864 error:
1865         kfree(_data);
1866         return ret;
1867 }
1868
1869 static int __ffs_data_got_strings(struct ffs_data *ffs,
1870                                   char *const _data, size_t len)
1871 {
1872         u32 str_count, needed_count, lang_count;
1873         struct usb_gadget_strings **stringtabs, *t;
1874         struct usb_string *strings, *s;
1875         const char *data = _data;
1876
1877         ENTER();
1878
1879         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
1880                      get_unaligned_le32(data + 4) != len))
1881                 goto error;
1882         str_count  = get_unaligned_le32(data + 8);
1883         lang_count = get_unaligned_le32(data + 12);
1884
1885         /* if one is zero the other must be zero */
1886         if (unlikely(!str_count != !lang_count))
1887                 goto error;
1888
1889         /* Do we have at least as many strings as descriptors need? */
1890         needed_count = ffs->strings_count;
1891         if (unlikely(str_count < needed_count))
1892                 goto error;
1893
1894         /*
1895          * If we don't need any strings just return and free all
1896          * memory.
1897          */
1898         if (!needed_count) {
1899                 kfree(_data);
1900                 return 0;
1901         }
1902
1903         /* Allocate everything in one chunk so there's less maintenance. */
1904         {
1905                 struct {
1906                         struct usb_gadget_strings *stringtabs[lang_count + 1];
1907                         struct usb_gadget_strings stringtab[lang_count];
1908                         struct usb_string strings[lang_count*(needed_count+1)];
1909                 } *d;
1910                 unsigned i = 0;
1911
1912                 d = kmalloc(sizeof *d, GFP_KERNEL);
1913                 if (unlikely(!d)) {
1914                         kfree(_data);
1915                         return -ENOMEM;
1916                 }
1917
1918                 stringtabs = d->stringtabs;
1919                 t = d->stringtab;
1920                 i = lang_count;
1921                 do {
1922                         *stringtabs++ = t++;
1923                 } while (--i);
1924                 *stringtabs = NULL;
1925
1926                 stringtabs = d->stringtabs;
1927                 t = d->stringtab;
1928                 s = d->strings;
1929                 strings = s;
1930         }
1931
1932         /* For each language */
1933         data += 16;
1934         len -= 16;
1935
1936         do { /* lang_count > 0 so we can use do-while */
1937                 unsigned needed = needed_count;
1938
1939                 if (unlikely(len < 3))
1940                         goto error_free;
1941                 t->language = get_unaligned_le16(data);
1942                 t->strings  = s;
1943                 ++t;
1944
1945                 data += 2;
1946                 len -= 2;
1947
1948                 /* For each string */
1949                 do { /* str_count > 0 so we can use do-while */
1950                         size_t length = strnlen(data, len);
1951
1952                         if (unlikely(length == len))
1953                                 goto error_free;
1954
1955                         /*
1956                          * User may provide more strings then we need,
1957                          * if that's the case we simply ignore the
1958                          * rest
1959                          */
1960                         if (likely(needed)) {
1961                                 /*
1962                                  * s->id will be set while adding
1963                                  * function to configuration so for
1964                                  * now just leave garbage here.
1965                                  */
1966                                 s->s = data;
1967                                 --needed;
1968                                 ++s;
1969                         }
1970
1971                         data += length + 1;
1972                         len -= length + 1;
1973                 } while (--str_count);
1974
1975                 s->id = 0;   /* terminator */
1976                 s->s = NULL;
1977                 ++s;
1978
1979         } while (--lang_count);
1980
1981         /* Some garbage left? */
1982         if (unlikely(len))
1983                 goto error_free;
1984
1985         /* Done! */
1986         ffs->stringtabs = stringtabs;
1987         ffs->raw_strings = _data;
1988
1989         return 0;
1990
1991 error_free:
1992         kfree(stringtabs);
1993 error:
1994         kfree(_data);
1995         return -EINVAL;
1996 }
1997
1998
1999 /* Events handling and management *******************************************/
2000
2001 static void __ffs_event_add(struct ffs_data *ffs,
2002                             enum usb_functionfs_event_type type)
2003 {
2004         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2005         int neg = 0;
2006
2007         /*
2008          * Abort any unhandled setup
2009          *
2010          * We do not need to worry about some cmpxchg() changing value
2011          * of ffs->setup_state without holding the lock because when
2012          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2013          * the source does nothing.
2014          */
2015         if (ffs->setup_state == FFS_SETUP_PENDING)
2016                 ffs->setup_state = FFS_SETUP_CANCELED;
2017
2018         switch (type) {
2019         case FUNCTIONFS_RESUME:
2020                 rem_type2 = FUNCTIONFS_SUSPEND;
2021                 /* FALL THROUGH */
2022         case FUNCTIONFS_SUSPEND:
2023         case FUNCTIONFS_SETUP:
2024                 rem_type1 = type;
2025                 /* Discard all similar events */
2026                 break;
2027
2028         case FUNCTIONFS_BIND:
2029         case FUNCTIONFS_UNBIND:
2030         case FUNCTIONFS_DISABLE:
2031         case FUNCTIONFS_ENABLE:
2032                 /* Discard everything other then power management. */
2033                 rem_type1 = FUNCTIONFS_SUSPEND;
2034                 rem_type2 = FUNCTIONFS_RESUME;
2035                 neg = 1;
2036                 break;
2037
2038         default:
2039                 BUG();
2040         }
2041
2042         {
2043                 u8 *ev  = ffs->ev.types, *out = ev;
2044                 unsigned n = ffs->ev.count;
2045                 for (; n; --n, ++ev)
2046                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2047                                 *out++ = *ev;
2048                         else
2049                                 pr_vdebug("purging event %d\n", *ev);
2050                 ffs->ev.count = out - ffs->ev.types;
2051         }
2052
2053         pr_vdebug("adding event %d\n", type);
2054         ffs->ev.types[ffs->ev.count++] = type;
2055         wake_up_locked(&ffs->ev.waitq);
2056 }
2057
2058 static void ffs_event_add(struct ffs_data *ffs,
2059                           enum usb_functionfs_event_type type)
2060 {
2061         unsigned long flags;
2062         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2063         __ffs_event_add(ffs, type);
2064         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2065 }
2066
2067
2068 /* Bind/unbind USB function hooks *******************************************/
2069
2070 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2071                                     struct usb_descriptor_header *desc,
2072                                     void *priv)
2073 {
2074         struct usb_endpoint_descriptor *ds = (void *)desc;
2075         struct ffs_function *func = priv;
2076         struct ffs_ep *ffs_ep;
2077
2078         /*
2079          * If hs_descriptors is not NULL then we are reading hs
2080          * descriptors now
2081          */
2082         const int isHS = func->function.hs_descriptors != NULL;
2083         unsigned idx;
2084
2085         if (type != FFS_DESCRIPTOR)
2086                 return 0;
2087
2088         if (isHS)
2089                 func->function.hs_descriptors[(long)valuep] = desc;
2090         else
2091                 func->function.descriptors[(long)valuep]    = desc;
2092
2093         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2094                 return 0;
2095
2096         idx = (ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK) - 1;
2097         ffs_ep = func->eps + idx;
2098
2099         if (unlikely(ffs_ep->descs[isHS])) {
2100                 pr_vdebug("two %sspeed descriptors for EP %d\n",
2101                           isHS ? "high" : "full",
2102                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2103                 return -EINVAL;
2104         }
2105         ffs_ep->descs[isHS] = ds;
2106
2107         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2108         if (ffs_ep->ep) {
2109                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2110                 if (!ds->wMaxPacketSize)
2111                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2112         } else {
2113                 struct usb_request *req;
2114                 struct usb_ep *ep;
2115
2116                 pr_vdebug("autoconfig\n");
2117                 ep = usb_ep_autoconfig(func->gadget, ds);
2118                 if (unlikely(!ep))
2119                         return -ENOTSUPP;
2120                 ep->driver_data = func->eps + idx;
2121
2122                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2123                 if (unlikely(!req))
2124                         return -ENOMEM;
2125
2126                 ffs_ep->ep  = ep;
2127                 ffs_ep->req = req;
2128                 func->eps_revmap[ds->bEndpointAddress &
2129                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2130         }
2131         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2132
2133         return 0;
2134 }
2135
2136 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2137                                    struct usb_descriptor_header *desc,
2138                                    void *priv)
2139 {
2140         struct ffs_function *func = priv;
2141         unsigned idx;
2142         u8 newValue;
2143
2144         switch (type) {
2145         default:
2146         case FFS_DESCRIPTOR:
2147                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2148                 return 0;
2149
2150         case FFS_INTERFACE:
2151                 idx = *valuep;
2152                 if (func->interfaces_nums[idx] < 0) {
2153                         int id = usb_interface_id(func->conf, &func->function);
2154                         if (unlikely(id < 0))
2155                                 return id;
2156                         func->interfaces_nums[idx] = id;
2157                 }
2158                 newValue = func->interfaces_nums[idx];
2159                 break;
2160
2161         case FFS_STRING:
2162                 /* String' IDs are allocated when fsf_data is bound to cdev */
2163                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2164                 break;
2165
2166         case FFS_ENDPOINT:
2167                 /*
2168                  * USB_DT_ENDPOINT are handled in
2169                  * __ffs_func_bind_do_descs().
2170                  */
2171                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2172                         return 0;
2173
2174                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2175                 if (unlikely(!func->eps[idx].ep))
2176                         return -EINVAL;
2177
2178                 {
2179                         struct usb_endpoint_descriptor **descs;
2180                         descs = func->eps[idx].descs;
2181                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2182                 }
2183                 break;
2184         }
2185
2186         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2187         *valuep = newValue;
2188         return 0;
2189 }
2190
2191 static int ffs_func_bind(struct usb_configuration *c,
2192                          struct usb_function *f)
2193 {
2194         struct ffs_function *func = ffs_func_from_usb(f);
2195         struct ffs_data *ffs = func->ffs;
2196
2197         const int full = !!func->ffs->fs_descs_count;
2198         const int high = gadget_is_dualspeed(func->gadget) &&
2199                 func->ffs->hs_descs_count;
2200
2201         int ret;
2202
2203         /* Make it a single chunk, less management later on */
2204         struct {
2205                 struct ffs_ep eps[ffs->eps_count];
2206                 struct usb_descriptor_header
2207                         *fs_descs[full ? ffs->fs_descs_count + 1 : 0];
2208                 struct usb_descriptor_header
2209                         *hs_descs[high ? ffs->hs_descs_count + 1 : 0];
2210                 short inums[ffs->interfaces_count];
2211                 char raw_descs[high ? ffs->raw_descs_length
2212                                     : ffs->raw_fs_descs_length];
2213         } *data;
2214
2215         ENTER();
2216
2217         /* Only high speed but not supported by gadget? */
2218         if (unlikely(!(full | high)))
2219                 return -ENOTSUPP;
2220
2221         /* Allocate */
2222         data = kmalloc(sizeof *data, GFP_KERNEL);
2223         if (unlikely(!data))
2224                 return -ENOMEM;
2225
2226         /* Zero */
2227         memset(data->eps, 0, sizeof data->eps);
2228         memcpy(data->raw_descs, ffs->raw_descs + 16, sizeof data->raw_descs);
2229         memset(data->inums, 0xff, sizeof data->inums);
2230         for (ret = ffs->eps_count; ret; --ret)
2231                 data->eps[ret].num = -1;
2232
2233         /* Save pointers */
2234         func->eps             = data->eps;
2235         func->interfaces_nums = data->inums;
2236
2237         /*
2238          * Go through all the endpoint descriptors and allocate
2239          * endpoints first, so that later we can rewrite the endpoint
2240          * numbers without worrying that it may be described later on.
2241          */
2242         if (likely(full)) {
2243                 func->function.descriptors = data->fs_descs;
2244                 ret = ffs_do_descs(ffs->fs_descs_count,
2245                                    data->raw_descs,
2246                                    sizeof data->raw_descs,
2247                                    __ffs_func_bind_do_descs, func);
2248                 if (unlikely(ret < 0))
2249                         goto error;
2250         } else {
2251                 ret = 0;
2252         }
2253
2254         if (likely(high)) {
2255                 func->function.hs_descriptors = data->hs_descs;
2256                 ret = ffs_do_descs(ffs->hs_descs_count,
2257                                    data->raw_descs + ret,
2258                                    (sizeof data->raw_descs) - ret,
2259                                    __ffs_func_bind_do_descs, func);
2260         }
2261
2262         /*
2263          * Now handle interface numbers allocation and interface and
2264          * endpoint numbers rewriting.  We can do that in one go
2265          * now.
2266          */
2267         ret = ffs_do_descs(ffs->fs_descs_count +
2268                            (high ? ffs->hs_descs_count : 0),
2269                            data->raw_descs, sizeof data->raw_descs,
2270                            __ffs_func_bind_do_nums, func);
2271         if (unlikely(ret < 0))
2272                 goto error;
2273
2274         /* And we're done */
2275         ffs_event_add(ffs, FUNCTIONFS_BIND);
2276         return 0;
2277
2278 error:
2279         /* XXX Do we need to release all claimed endpoints here? */
2280         return ret;
2281 }
2282
2283
2284 /* Other USB function hooks *************************************************/
2285
2286 static void ffs_func_unbind(struct usb_configuration *c,
2287                             struct usb_function *f)
2288 {
2289         struct ffs_function *func = ffs_func_from_usb(f);
2290         struct ffs_data *ffs = func->ffs;
2291
2292         ENTER();
2293
2294         if (ffs->func == func) {
2295                 ffs_func_eps_disable(func);
2296                 ffs->func = NULL;
2297         }
2298
2299         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
2300
2301         ffs_func_free(func);
2302 }
2303
2304 static int ffs_func_set_alt(struct usb_function *f,
2305                             unsigned interface, unsigned alt)
2306 {
2307         struct ffs_function *func = ffs_func_from_usb(f);
2308         struct ffs_data *ffs = func->ffs;
2309         int ret = 0, intf;
2310
2311         if (alt != (unsigned)-1) {
2312                 intf = ffs_func_revmap_intf(func, interface);
2313                 if (unlikely(intf < 0))
2314                         return intf;
2315         }
2316
2317         if (ffs->func)
2318                 ffs_func_eps_disable(ffs->func);
2319
2320         if (ffs->state != FFS_ACTIVE)
2321                 return -ENODEV;
2322
2323         if (alt == (unsigned)-1) {
2324                 ffs->func = NULL;
2325                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2326                 return 0;
2327         }
2328
2329         ffs->func = func;
2330         ret = ffs_func_eps_enable(func);
2331         if (likely(ret >= 0))
2332                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2333         return ret;
2334 }
2335
2336 static void ffs_func_disable(struct usb_function *f)
2337 {
2338         ffs_func_set_alt(f, 0, (unsigned)-1);
2339 }
2340
2341 static int ffs_func_setup(struct usb_function *f,
2342                           const struct usb_ctrlrequest *creq)
2343 {
2344         struct ffs_function *func = ffs_func_from_usb(f);
2345         struct ffs_data *ffs = func->ffs;
2346         unsigned long flags;
2347         int ret;
2348
2349         ENTER();
2350
2351         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2352         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2353         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2354         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
2355         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
2356
2357         /*
2358          * Most requests directed to interface go through here
2359          * (notable exceptions are set/get interface) so we need to
2360          * handle them.  All other either handled by composite or
2361          * passed to usb_configuration->setup() (if one is set).  No
2362          * matter, we will handle requests directed to endpoint here
2363          * as well (as it's straightforward) but what to do with any
2364          * other request?
2365          */
2366         if (ffs->state != FFS_ACTIVE)
2367                 return -ENODEV;
2368
2369         switch (creq->bRequestType & USB_RECIP_MASK) {
2370         case USB_RECIP_INTERFACE:
2371                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
2372                 if (unlikely(ret < 0))
2373                         return ret;
2374                 break;
2375
2376         case USB_RECIP_ENDPOINT:
2377                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
2378                 if (unlikely(ret < 0))
2379                         return ret;
2380                 break;
2381
2382         default:
2383                 return -EOPNOTSUPP;
2384         }
2385
2386         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2387         ffs->ev.setup = *creq;
2388         ffs->ev.setup.wIndex = cpu_to_le16(ret);
2389         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
2390         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2391
2392         return 0;
2393 }
2394
2395 static void ffs_func_suspend(struct usb_function *f)
2396 {
2397         ENTER();
2398         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
2399 }
2400
2401 static void ffs_func_resume(struct usb_function *f)
2402 {
2403         ENTER();
2404         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
2405 }
2406
2407
2408 /* Endpoint and interface numbers reverse mapping ***************************/
2409
2410 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
2411 {
2412         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
2413         return num ? num : -EDOM;
2414 }
2415
2416 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
2417 {
2418         short *nums = func->interfaces_nums;
2419         unsigned count = func->ffs->interfaces_count;
2420
2421         for (; count; --count, ++nums) {
2422                 if (*nums >= 0 && *nums == intf)
2423                         return nums - func->interfaces_nums;
2424         }
2425
2426         return -EDOM;
2427 }
2428
2429
2430 /* Misc helper functions ****************************************************/
2431
2432 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
2433 {
2434         return nonblock
2435                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
2436                 : mutex_lock_interruptible(mutex);
2437 }
2438
2439 static char *ffs_prepare_buffer(const char * __user buf, size_t len)
2440 {
2441         char *data;
2442
2443         if (unlikely(!len))
2444                 return NULL;
2445
2446         data = kmalloc(len, GFP_KERNEL);
2447         if (unlikely(!data))
2448                 return ERR_PTR(-ENOMEM);
2449
2450         if (unlikely(__copy_from_user(data, buf, len))) {
2451                 kfree(data);
2452                 return ERR_PTR(-EFAULT);
2453         }
2454
2455         pr_vdebug("Buffer from user space:\n");
2456         ffs_dump_mem("", data, len);
2457
2458         return data;
2459 }