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 <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                 kuid_t                          uid;
 228                 kgid_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         .llseek =       no_llseek,
 731
 732         .open =         ffs_ep0_open,
 733         .write =        ffs_ep0_write,
 734         .read =         ffs_ep0_read,
 735         .release =      ffs_ep0_release,
 736         .unlocked_ioctl =       ffs_ep0_ioctl,
 737 };
 738
 739
 740 /* "Normal" endpoints operations ********************************************/
 741
 742 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 743 {
 744         ENTER();
 745         if (likely(req->context)) {
 746                 struct ffs_ep *ep = _ep->driver_data;
 747                 ep->status = req->status ? req->status : req->actual;
 748                 complete(req->context);
 749         }
 750 }
 751
 752 static ssize_t ffs_epfile_io(struct file *file,
 753                              char __user *buf, size_t len, int read)
 754 {
 755         struct ffs_epfile *epfile = file->private_data;
 756         struct ffs_ep *ep;
 757         char *data = NULL;
 758         ssize_t ret;
 759         int halt;
 760
 761         goto first_try;
 762         do {
 763                 spin_unlock_irq(&epfile->ffs->eps_lock);
 764                 mutex_unlock(&epfile->mutex);
 765
 766 first_try:
 767                 /* Are we still active? */
 768                 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
 769                         ret = -ENODEV;
 770                         goto error;
 771                 }
 772
 773                 /* Wait for endpoint to be enabled */
 774                 ep = epfile->ep;
 775                 if (!ep) {
 776                         if (file->f_flags & O_NONBLOCK) {
 777                                 ret = -EAGAIN;
 778                                 goto error;
 779                         }
 780
 781                         if (wait_event_interruptible(epfile->wait,
 782                                                      (ep = epfile->ep))) {
 783                                 ret = -EINTR;
 784                                 goto error;
 785                         }
 786                 }
 787
 788                 /* Do we halt? */
 789                 halt = !read == !epfile->in;
 790                 if (halt && epfile->isoc) {
 791                         ret = -EINVAL;
 792                         goto error;
 793                 }
 794
 795                 /* Allocate & copy */
 796                 if (!halt && !data) {
 797                         data = kzalloc(len, GFP_KERNEL);
 798                         if (unlikely(!data))
 799                                 return -ENOMEM;
 800
 801                         if (!read &&
 802                             unlikely(__copy_from_user(data, buf, len))) {
 803                                 ret = -EFAULT;
 804                                 goto error;
 805                         }
 806                 }
 807
 808                 /* We will be using request */
 809                 ret = ffs_mutex_lock(&epfile->mutex,
 810                                      file->f_flags & O_NONBLOCK);
 811                 if (unlikely(ret))
 812                         goto error;
 813
 814                 /*
 815                  * We're called from user space, we can use _irq rather then
 816                  * _irqsave
 817                  */
 818                 spin_lock_irq(&epfile->ffs->eps_lock);
 819
 820                 /*
 821                  * While we were acquiring mutex endpoint got disabled
 822                  * or changed?
 823                  */
 824         } while (unlikely(epfile->ep != ep));
 825
 826         /* Halt */
 827         if (unlikely(halt)) {
 828                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 829                         usb_ep_set_halt(ep->ep);
 830                 spin_unlock_irq(&epfile->ffs->eps_lock);
 831                 ret = -EBADMSG;
 832         } else {
 833                 /* Fire the request */
 834                 DECLARE_COMPLETION_ONSTACK(done);
 835
 836                 struct usb_request *req = ep->req;
 837                 req->context  = &done;
 838                 req->complete = ffs_epfile_io_complete;
 839                 req->buf      = data;
 840                 req->length   = len;
 841
 842                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 843
 844                 spin_unlock_irq(&epfile->ffs->eps_lock);
 845
 846                 if (unlikely(ret < 0)) {
 847                         /* nop */
 848                 } else if (unlikely(wait_for_completion_interruptible(&done))) {
 849                         ret = -EINTR;
 850                         usb_ep_dequeue(ep->ep, req);
 851                 } else {
 852                         ret = ep->status;
 853                         if (read && ret > 0 &&
 854                             unlikely(copy_to_user(buf, data, ret)))
 855                                 ret = -EFAULT;
 856                 }
 857         }
 858
 859         mutex_unlock(&epfile->mutex);
 860 error:
 861         kfree(data);
 862         return ret;
 863 }
 864
 865 static ssize_t
 866 ffs_epfile_write(struct file *file, const char __user *buf, size_t len,
 867                  loff_t *ptr)
 868 {
 869         ENTER();
 870
 871         return ffs_epfile_io(file, (char __user *)buf, len, 0);
 872 }
 873
 874 static ssize_t
 875 ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr)
 876 {
 877         ENTER();
 878
 879         return ffs_epfile_io(file, buf, len, 1);
 880 }
 881
 882 static int
 883 ffs_epfile_open(struct inode *inode, struct file *file)
 884 {
 885         struct ffs_epfile *epfile = inode->i_private;
 886
 887         ENTER();
 888
 889         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 890                 return -ENODEV;
 891
 892         file->private_data = epfile;
 893         ffs_data_opened(epfile->ffs);
 894
 895         return 0;
 896 }
 897
 898 static int
 899 ffs_epfile_release(struct inode *inode, struct file *file)
 900 {
 901         struct ffs_epfile *epfile = inode->i_private;
 902
 903         ENTER();
 904
 905         ffs_data_closed(epfile->ffs);
 906
 907         return 0;
 908 }
 909
 910 static long ffs_epfile_ioctl(struct file *file, unsigned code,
 911                              unsigned long value)
 912 {
 913         struct ffs_epfile *epfile = file->private_data;
 914         int ret;
 915
 916         ENTER();
 917
 918         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 919                 return -ENODEV;
 920
 921         spin_lock_irq(&epfile->ffs->eps_lock);
 922         if (likely(epfile->ep)) {
 923                 switch (code) {
 924                 case FUNCTIONFS_FIFO_STATUS:
 925                         ret = usb_ep_fifo_status(epfile->ep->ep);
 926                         break;
 927                 case FUNCTIONFS_FIFO_FLUSH:
 928                         usb_ep_fifo_flush(epfile->ep->ep);
 929                         ret = 0;
 930                         break;
 931                 case FUNCTIONFS_CLEAR_HALT:
 932                         ret = usb_ep_clear_halt(epfile->ep->ep);
 933                         break;
 934                 case FUNCTIONFS_ENDPOINT_REVMAP:
 935                         ret = epfile->ep->num;
 936                         break;
 937                 default:
 938                         ret = -ENOTTY;
 939                 }
 940         } else {
 941                 ret = -ENODEV;
 942         }
 943         spin_unlock_irq(&epfile->ffs->eps_lock);
 944
 945         return ret;
 946 }
 947
 948 static const struct file_operations ffs_epfile_operations = {
 949         .llseek =       no_llseek,
 950
 951         .open =         ffs_epfile_open,
 952         .write =        ffs_epfile_write,
 953         .read =         ffs_epfile_read,
 954         .release =      ffs_epfile_release,
 955         .unlocked_ioctl =       ffs_epfile_ioctl,
 956 };
 957
 958
 959 /* File system and super block operations ***********************************/
 960
 961 /*
 962  * Mounting the file system creates a controller file, used first for
 963  * function configuration then later for event monitoring.
 964  */
 965
 966 static struct inode *__must_check
 967 ffs_sb_make_inode(struct super_block *sb, void *data,
 968                   const struct file_operations *fops,
 969                   const struct inode_operations *iops,
 970                   struct ffs_file_perms *perms)
 971 {
 972         struct inode *inode;
 973
 974         ENTER();
 975
 976         inode = new_inode(sb);
 977
 978         if (likely(inode)) {
 979                 struct timespec current_time = CURRENT_TIME;
 980
 981                 inode->i_ino     = get_next_ino();
 982                 inode->i_mode    = perms->mode;
 983                 inode->i_uid     = perms->uid;
 984                 inode->i_gid     = perms->gid;
 985                 inode->i_atime   = current_time;
 986                 inode->i_mtime   = current_time;
 987                 inode->i_ctime   = current_time;
 988                 inode->i_private = data;
 989                 if (fops)
 990                         inode->i_fop = fops;
 991                 if (iops)
 992                         inode->i_op  = iops;
 993         }
 994
 995         return inode;
 996 }
 997
 998 /* Create "regular" file */
 999 static struct inode *ffs_sb_create_file(struct super_block *sb,
1000                                         const char *name, void *data,
1001                                         const struct file_operations *fops,
1002                                         struct dentry **dentry_p)
1003 {
1004         struct ffs_data *ffs = sb->s_fs_info;
1005         struct dentry   *dentry;
1006         struct inode    *inode;
1007
1008         ENTER();
1009
1010         dentry = d_alloc_name(sb->s_root, name);
1011         if (unlikely(!dentry))
1012                 return NULL;
1013
1014         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1015         if (unlikely(!inode)) {
1016                 dput(dentry);
1017                 return NULL;
1018         }
1019
1020         d_add(dentry, inode);
1021         if (dentry_p)
1022                 *dentry_p = dentry;
1023
1024         return inode;
1025 }
1026
1027 /* Super block */
1028 static const struct super_operations ffs_sb_operations = {
1029         .statfs =       simple_statfs,
1030         .drop_inode =   generic_delete_inode,
1031 };
1032
1033 struct ffs_sb_fill_data {
1034         struct ffs_file_perms perms;
1035         umode_t root_mode;
1036         const char *dev_name;
1037         struct ffs_data *ffs_data;
1038 };
1039
1040 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1041 {
1042         struct ffs_sb_fill_data *data = _data;
1043         struct inode    *inode;
1044         struct ffs_data *ffs = data->ffs_data;
1045
1046         ENTER();
1047
1048         ffs->sb              = sb;
1049         data->ffs_data       = NULL;
1050         sb->s_fs_info        = ffs;
1051         sb->s_blocksize      = PAGE_CACHE_SIZE;
1052         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1053         sb->s_magic          = FUNCTIONFS_MAGIC;
1054         sb->s_op             = &ffs_sb_operations;
1055         sb->s_time_gran      = 1;
1056
1057         /* Root inode */
1058         data->perms.mode = data->root_mode;
1059         inode = ffs_sb_make_inode(sb, NULL,
1060                                   &simple_dir_operations,
1061                                   &simple_dir_inode_operations,
1062                                   &data->perms);
1063         sb->s_root = d_make_root(inode);
1064         if (unlikely(!sb->s_root))
1065                 return -ENOMEM;
1066
1067         /* EP0 file */
1068         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1069                                          &ffs_ep0_operations, NULL)))
1070                 return -ENOMEM;
1071
1072         return 0;
1073 }
1074
1075 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1076 {
1077         ENTER();
1078
1079         if (!opts || !*opts)
1080                 return 0;
1081
1082         for (;;) {
1083                 unsigned long value;
1084                 char *eq, *comma;
1085
1086                 /* Option limit */
1087                 comma = strchr(opts, ',');
1088                 if (comma)
1089                         *comma = 0;
1090
1091                 /* Value limit */
1092                 eq = strchr(opts, '=');
1093                 if (unlikely(!eq)) {
1094                         pr_err("'=' missing in %s\n", opts);
1095                         return -EINVAL;
1096                 }
1097                 *eq = 0;
1098
1099                 /* Parse value */
1100                 if (kstrtoul(eq + 1, 0, &value)) {
1101                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1102                         return -EINVAL;
1103                 }
1104
1105                 /* Interpret option */
1106                 switch (eq - opts) {
1107                 case 5:
1108                         if (!memcmp(opts, "rmode", 5))
1109                                 data->root_mode  = (value & 0555) | S_IFDIR;
1110                         else if (!memcmp(opts, "fmode", 5))
1111                                 data->perms.mode = (value & 0666) | S_IFREG;
1112                         else
1113                                 goto invalid;
1114                         break;
1115
1116                 case 4:
1117                         if (!memcmp(opts, "mode", 4)) {
1118                                 data->root_mode  = (value & 0555) | S_IFDIR;
1119                                 data->perms.mode = (value & 0666) | S_IFREG;
1120                         } else {
1121                                 goto invalid;
1122                         }
1123                         break;
1124
1125                 case 3:
1126                         if (!memcmp(opts, "uid", 3)) {
1127                                 data->perms.uid = make_kuid(current_user_ns(), value);
1128                                 if (!uid_valid(data->perms.uid)) {
1129                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1130                                         return -EINVAL;
1131                                 }
1132                         } else if (!memcmp(opts, "gid", 3)) {
1133                                 data->perms.gid = make_kgid(current_user_ns(), value);
1134                                 if (!gid_valid(data->perms.gid)) {
1135                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1136                                         return -EINVAL;
1137                                 }
1138                         } else {
1139                                 goto invalid;
1140                         }
1141                         break;
1142
1143                 default:
1144 invalid:
1145                         pr_err("%s: invalid option\n", opts);
1146                         return -EINVAL;
1147                 }
1148
1149                 /* Next iteration */
1150                 if (!comma)
1151                         break;
1152                 opts = comma + 1;
1153         }
1154
1155         return 0;
1156 }
1157
1158 /* "mount -t functionfs dev_name /dev/function" ends up here */
1159
1160 static struct dentry *
1161 ffs_fs_mount(struct file_system_type *t, int flags,
1162               const char *dev_name, void *opts)
1163 {
1164         struct ffs_sb_fill_data data = {
1165                 .perms = {
1166                         .mode = S_IFREG | 0600,
1167                         .uid = GLOBAL_ROOT_UID,
1168                         .gid = GLOBAL_ROOT_GID,
1169                 },
1170                 .root_mode = S_IFDIR | 0500,
1171         };
1172         struct dentry *rv;
1173         int ret;
1174         void *ffs_dev;
1175         struct ffs_data *ffs;
1176
1177         ENTER();
1178
1179         ret = ffs_fs_parse_opts(&data, opts);
1180         if (unlikely(ret < 0))
1181                 return ERR_PTR(ret);
1182
1183         ffs = ffs_data_new();
1184         if (unlikely(!ffs))
1185                 return ERR_PTR(-ENOMEM);
1186         ffs->file_perms = data.perms;
1187
1188         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1189         if (unlikely(!ffs->dev_name)) {
1190                 ffs_data_put(ffs);
1191                 return ERR_PTR(-ENOMEM);
1192         }
1193
1194         ffs_dev = functionfs_acquire_dev_callback(dev_name);
1195         if (IS_ERR(ffs_dev)) {
1196                 ffs_data_put(ffs);
1197                 return ERR_CAST(ffs_dev);
1198         }
1199         ffs->private_data = ffs_dev;
1200         data.ffs_data = ffs;
1201
1202         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1203         if (IS_ERR(rv) && data.ffs_data) {
1204                 functionfs_release_dev_callback(data.ffs_data);
1205                 ffs_data_put(data.ffs_data);
1206         }
1207         return rv;
1208 }
1209
1210 static void
1211 ffs_fs_kill_sb(struct super_block *sb)
1212 {
1213         ENTER();
1214
1215         kill_litter_super(sb);
1216         if (sb->s_fs_info) {
1217                 functionfs_release_dev_callback(sb->s_fs_info);
1218                 ffs_data_put(sb->s_fs_info);
1219         }
1220 }
1221
1222 static struct file_system_type ffs_fs_type = {
1223         .owner          = THIS_MODULE,
1224         .name           = "functionfs",
1225         .mount          = ffs_fs_mount,
1226         .kill_sb        = ffs_fs_kill_sb,
1227 };
1228 MODULE_ALIAS_FS("functionfs");
1229
1230
1231 /* Driver's main init/cleanup functions *************************************/
1232
1233 static int functionfs_init(void)
1234 {
1235         int ret;
1236
1237         ENTER();
1238
1239         ret = register_filesystem(&ffs_fs_type);
1240         if (likely(!ret))
1241                 pr_info("file system registered\n");
1242         else
1243                 pr_err("failed registering file system (%d)\n", ret);
1244
1245         return ret;
1246 }
1247
1248 static void functionfs_cleanup(void)
1249 {
1250         ENTER();
1251
1252         pr_info("unloading\n");
1253         unregister_filesystem(&ffs_fs_type);
1254 }
1255
1256
1257 /* ffs_data and ffs_function construction and destruction code **************/
1258
1259 static void ffs_data_clear(struct ffs_data *ffs);
1260 static void ffs_data_reset(struct ffs_data *ffs);
1261
1262 static void ffs_data_get(struct ffs_data *ffs)
1263 {
1264         ENTER();
1265
1266         atomic_inc(&ffs->ref);
1267 }
1268
1269 static void ffs_data_opened(struct ffs_data *ffs)
1270 {
1271         ENTER();
1272
1273         atomic_inc(&ffs->ref);
1274         atomic_inc(&ffs->opened);
1275 }
1276
1277 static void ffs_data_put(struct ffs_data *ffs)
1278 {
1279         ENTER();
1280
1281         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1282                 pr_info("%s(): freeing\n", __func__);
1283                 ffs_data_clear(ffs);
1284                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1285                        waitqueue_active(&ffs->ep0req_completion.wait));
1286                 kfree(ffs->dev_name);
1287                 kfree(ffs);
1288         }
1289 }
1290
1291 static void ffs_data_closed(struct ffs_data *ffs)
1292 {
1293         ENTER();
1294
1295         if (atomic_dec_and_test(&ffs->opened)) {
1296                 ffs->state = FFS_CLOSING;
1297                 ffs_data_reset(ffs);
1298         }
1299
1300         ffs_data_put(ffs);
1301 }
1302
1303 static struct ffs_data *ffs_data_new(void)
1304 {
1305         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1306         if (unlikely(!ffs))
1307                 return 0;
1308
1309         ENTER();
1310
1311         atomic_set(&ffs->ref, 1);
1312         atomic_set(&ffs->opened, 0);
1313         ffs->state = FFS_READ_DESCRIPTORS;
1314         mutex_init(&ffs->mutex);
1315         spin_lock_init(&ffs->eps_lock);
1316         init_waitqueue_head(&ffs->ev.waitq);
1317         init_completion(&ffs->ep0req_completion);
1318
1319         /* XXX REVISIT need to update it in some places, or do we? */
1320         ffs->ev.can_stall = 1;
1321
1322         return ffs;
1323 }
1324
1325 static void ffs_data_clear(struct ffs_data *ffs)
1326 {
1327         ENTER();
1328
1329         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags))
1330                 functionfs_closed_callback(ffs);
1331
1332         BUG_ON(ffs->gadget);
1333
1334         if (ffs->epfiles)
1335                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1336
1337         kfree(ffs->raw_descs);
1338         kfree(ffs->raw_strings);
1339         kfree(ffs->stringtabs);
1340 }
1341
1342 static void ffs_data_reset(struct ffs_data *ffs)
1343 {
1344         ENTER();
1345
1346         ffs_data_clear(ffs);
1347
1348         ffs->epfiles = NULL;
1349         ffs->raw_descs = NULL;
1350         ffs->raw_strings = NULL;
1351         ffs->stringtabs = NULL;
1352
1353         ffs->raw_descs_length = 0;
1354         ffs->raw_fs_descs_length = 0;
1355         ffs->fs_descs_count = 0;
1356         ffs->hs_descs_count = 0;
1357
1358         ffs->strings_count = 0;
1359         ffs->interfaces_count = 0;
1360         ffs->eps_count = 0;
1361
1362         ffs->ev.count = 0;
1363
1364         ffs->state = FFS_READ_DESCRIPTORS;
1365         ffs->setup_state = FFS_NO_SETUP;
1366         ffs->flags = 0;
1367 }
1368
1369
1370 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1371 {
1372         struct usb_gadget_strings **lang;
1373         int first_id;
1374
1375         ENTER();
1376
1377         if (WARN_ON(ffs->state != FFS_ACTIVE
1378                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1379                 return -EBADFD;
1380
1381         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1382         if (unlikely(first_id < 0))
1383                 return first_id;
1384
1385         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1386         if (unlikely(!ffs->ep0req))
1387                 return -ENOMEM;
1388         ffs->ep0req->complete = ffs_ep0_complete;
1389         ffs->ep0req->context = ffs;
1390
1391         lang = ffs->stringtabs;
1392         if (lang) {
1393                 for (; *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
1401         ffs->gadget = cdev->gadget;
1402         ffs_data_get(ffs);
1403         return 0;
1404 }
1405
1406 static void functionfs_unbind(struct ffs_data *ffs)
1407 {
1408         ENTER();
1409
1410         if (!WARN_ON(!ffs->gadget)) {
1411                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1412                 ffs->ep0req = NULL;
1413                 ffs->gadget = NULL;
1414                 ffs_data_put(ffs);
1415                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1416         }
1417 }
1418
1419 static int ffs_epfiles_create(struct ffs_data *ffs)
1420 {
1421         struct ffs_epfile *epfile, *epfiles;
1422         unsigned i, count;
1423
1424         ENTER();
1425
1426         count = ffs->eps_count;
1427         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1428         if (!epfiles)
1429                 return -ENOMEM;
1430
1431         epfile = epfiles;
1432         for (i = 1; i <= count; ++i, ++epfile) {
1433                 epfile->ffs = ffs;
1434                 mutex_init(&epfile->mutex);
1435                 init_waitqueue_head(&epfile->wait);
1436                 sprintf(epfiles->name, "ep%u",  i);
1437                 if (!unlikely(ffs_sb_create_file(ffs->sb, epfiles->name, epfile,
1438                                                  &ffs_epfile_operations,
1439                                                  &epfile->dentry))) {
1440                         ffs_epfiles_destroy(epfiles, i - 1);
1441                         return -ENOMEM;
1442                 }
1443         }
1444
1445         ffs->epfiles = epfiles;
1446         return 0;
1447 }
1448
1449 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1450 {
1451         struct ffs_epfile *epfile = epfiles;
1452
1453         ENTER();
1454
1455         for (; count; --count, ++epfile) {
1456                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1457                        waitqueue_active(&epfile->wait));
1458                 if (epfile->dentry) {
1459                         d_delete(epfile->dentry);
1460                         dput(epfile->dentry);
1461                         epfile->dentry = NULL;
1462                 }
1463         }
1464
1465         kfree(epfiles);
1466 }
1467
1468 static int functionfs_bind_config(struct usb_composite_dev *cdev,
1469                                   struct usb_configuration *c,
1470                                   struct ffs_data *ffs)
1471 {
1472         struct ffs_function *func;
1473         int ret;
1474
1475         ENTER();
1476
1477         func = kzalloc(sizeof *func, GFP_KERNEL);
1478         if (unlikely(!func))
1479                 return -ENOMEM;
1480
1481         func->function.name    = "Function FS Gadget";
1482         func->function.strings = ffs->stringtabs;
1483
1484         func->function.bind    = ffs_func_bind;
1485         func->function.unbind  = ffs_func_unbind;
1486         func->function.set_alt = ffs_func_set_alt;
1487         func->function.disable = ffs_func_disable;
1488         func->function.setup   = ffs_func_setup;
1489         func->function.suspend = ffs_func_suspend;
1490         func->function.resume  = ffs_func_resume;
1491
1492         func->conf   = c;
1493         func->gadget = cdev->gadget;
1494         func->ffs = ffs;
1495         ffs_data_get(ffs);
1496
1497         ret = usb_add_function(c, &func->function);
1498         if (unlikely(ret))
1499                 ffs_func_free(func);
1500
1501         return ret;
1502 }
1503
1504 static void ffs_func_free(struct ffs_function *func)
1505 {
1506         struct ffs_ep *ep         = func->eps;
1507         unsigned count            = func->ffs->eps_count;
1508         unsigned long flags;
1509
1510         ENTER();
1511
1512         /* cleanup after autoconfig */
1513         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1514         do {
1515                 if (ep->ep && ep->req)
1516                         usb_ep_free_request(ep->ep, ep->req);
1517                 ep->req = NULL;
1518                 ++ep;
1519         } while (--count);
1520         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1521
1522         ffs_data_put(func->ffs);
1523
1524         kfree(func->eps);
1525         /*
1526          * eps and interfaces_nums are allocated in the same chunk so
1527          * only one free is required.  Descriptors are also allocated
1528          * in the same chunk.
1529          */
1530
1531         kfree(func);
1532 }
1533
1534 static void ffs_func_eps_disable(struct ffs_function *func)
1535 {
1536         struct ffs_ep *ep         = func->eps;
1537         struct ffs_epfile *epfile = func->ffs->epfiles;
1538         unsigned count            = func->ffs->eps_count;
1539         unsigned long flags;
1540
1541         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1542         do {
1543                 /* pending requests get nuked */
1544                 if (likely(ep->ep))
1545                         usb_ep_disable(ep->ep);
1546                 epfile->ep = NULL;
1547
1548                 ++ep;
1549                 ++epfile;
1550         } while (--count);
1551         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1552 }
1553
1554 static int ffs_func_eps_enable(struct ffs_function *func)
1555 {
1556         struct ffs_data *ffs      = func->ffs;
1557         struct ffs_ep *ep         = func->eps;
1558         struct ffs_epfile *epfile = ffs->epfiles;
1559         unsigned count            = ffs->eps_count;
1560         unsigned long flags;
1561         int ret = 0;
1562
1563         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1564         do {
1565                 struct usb_endpoint_descriptor *ds;
1566                 int desc_idx = ffs->gadget->speed == USB_SPEED_HIGH ? 1 : 0;
1567                 ds = ep->descs[desc_idx];
1568                 if (!ds) {
1569                         ret = -EINVAL;
1570                         break;
1571                 }
1572
1573                 ep->ep->driver_data = ep;
1574                 ep->ep->desc = ds;
1575                 ret = usb_ep_enable(ep->ep);
1576                 if (likely(!ret)) {
1577                         epfile->ep = ep;
1578                         epfile->in = usb_endpoint_dir_in(ds);
1579                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1580                 } else {
1581                         break;
1582                 }
1583
1584                 wake_up(&epfile->wait);
1585
1586                 ++ep;
1587                 ++epfile;
1588         } while (--count);
1589         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1590
1591         return ret;
1592 }
1593
1594
1595 /* Parsing and building descriptors and strings *****************************/
1596
1597 /*
1598  * This validates if data pointed by data is a valid USB descriptor as
1599  * well as record how many interfaces, endpoints and strings are
1600  * required by given configuration.  Returns address after the
1601  * descriptor or NULL if data is invalid.
1602  */
1603
1604 enum ffs_entity_type {
1605         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1606 };
1607
1608 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1609                                    u8 *valuep,
1610                                    struct usb_descriptor_header *desc,
1611                                    void *priv);
1612
1613 static int __must_check ffs_do_desc(char *data, unsigned len,
1614                                     ffs_entity_callback entity, void *priv)
1615 {
1616         struct usb_descriptor_header *_ds = (void *)data;
1617         u8 length;
1618         int ret;
1619
1620         ENTER();
1621
1622         /* At least two bytes are required: length and type */
1623         if (len < 2) {
1624                 pr_vdebug("descriptor too short\n");
1625                 return -EINVAL;
1626         }
1627
1628         /* If we have at least as many bytes as the descriptor takes? */
1629         length = _ds->bLength;
1630         if (len < length) {
1631                 pr_vdebug("descriptor longer then available data\n");
1632                 return -EINVAL;
1633         }
1634
1635 #define __entity_check_INTERFACE(val)  1
1636 #define __entity_check_STRING(val)     (val)
1637 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1638 #define __entity(type, val) do {                                        \
1639                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1640                 if (unlikely(!__entity_check_ ##type(val))) {           \
1641                         pr_vdebug("invalid entity's value\n");          \
1642                         return -EINVAL;                                 \
1643                 }                                                       \
1644                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1645                 if (unlikely(ret < 0)) {                                \
1646                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1647                                  (val), ret);                           \
1648                         return ret;                                     \
1649                 }                                                       \
1650         } while (0)
1651
1652         /* Parse descriptor depending on type. */
1653         switch (_ds->bDescriptorType) {
1654         case USB_DT_DEVICE:
1655         case USB_DT_CONFIG:
1656         case USB_DT_STRING:
1657         case USB_DT_DEVICE_QUALIFIER:
1658                 /* function can't have any of those */
1659                 pr_vdebug("descriptor reserved for gadget: %d\n",
1660                       _ds->bDescriptorType);
1661                 return -EINVAL;
1662
1663         case USB_DT_INTERFACE: {
1664                 struct usb_interface_descriptor *ds = (void *)_ds;
1665                 pr_vdebug("interface descriptor\n");
1666                 if (length != sizeof *ds)
1667                         goto inv_length;
1668
1669                 __entity(INTERFACE, ds->bInterfaceNumber);
1670                 if (ds->iInterface)
1671                         __entity(STRING, ds->iInterface);
1672         }
1673                 break;
1674
1675         case USB_DT_ENDPOINT: {
1676                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1677                 pr_vdebug("endpoint descriptor\n");
1678                 if (length != USB_DT_ENDPOINT_SIZE &&
1679                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1680                         goto inv_length;
1681                 __entity(ENDPOINT, ds->bEndpointAddress);
1682         }
1683                 break;
1684
1685         case HID_DT_HID:
1686                 pr_vdebug("hid descriptor\n");
1687                 if (length != sizeof(struct hid_descriptor))
1688                         goto inv_length;
1689                 break;
1690
1691         case USB_DT_OTG:
1692                 if (length != sizeof(struct usb_otg_descriptor))
1693                         goto inv_length;
1694                 break;
1695
1696         case USB_DT_INTERFACE_ASSOCIATION: {
1697                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1698                 pr_vdebug("interface association descriptor\n");
1699                 if (length != sizeof *ds)
1700                         goto inv_length;
1701                 if (ds->iFunction)
1702                         __entity(STRING, ds->iFunction);
1703         }
1704                 break;
1705
1706         case USB_DT_OTHER_SPEED_CONFIG:
1707         case USB_DT_INTERFACE_POWER:
1708         case USB_DT_DEBUG:
1709         case USB_DT_SECURITY:
1710         case USB_DT_CS_RADIO_CONTROL:
1711                 /* TODO */
1712                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1713                 return -EINVAL;
1714
1715         default:
1716                 /* We should never be here */
1717                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1718                 return -EINVAL;
1719
1720 inv_length:
1721                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1722                           _ds->bLength, _ds->bDescriptorType);
1723                 return -EINVAL;
1724         }
1725
1726 #undef __entity
1727 #undef __entity_check_DESCRIPTOR
1728 #undef __entity_check_INTERFACE
1729 #undef __entity_check_STRING
1730 #undef __entity_check_ENDPOINT
1731
1732         return length;
1733 }
1734
1735 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1736                                      ffs_entity_callback entity, void *priv)
1737 {
1738         const unsigned _len = len;
1739         unsigned long num = 0;
1740
1741         ENTER();
1742
1743         for (;;) {
1744                 int ret;
1745
1746                 if (num == count)
1747                         data = NULL;
1748
1749                 /* Record "descriptor" entity */
1750                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1751                 if (unlikely(ret < 0)) {
1752                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1753                                  num, ret);
1754                         return ret;
1755                 }
1756
1757                 if (!data)
1758                         return _len - len;
1759
1760                 ret = ffs_do_desc(data, len, entity, priv);
1761                 if (unlikely(ret < 0)) {
1762                         pr_debug("%s returns %d\n", __func__, ret);
1763                         return ret;
1764                 }
1765
1766                 len -= ret;
1767                 data += ret;
1768                 ++num;
1769         }
1770 }
1771
1772 static int __ffs_data_do_entity(enum ffs_entity_type type,
1773                                 u8 *valuep, struct usb_descriptor_header *desc,
1774                                 void *priv)
1775 {
1776         struct ffs_data *ffs = priv;
1777
1778         ENTER();
1779
1780         switch (type) {
1781         case FFS_DESCRIPTOR:
1782                 break;
1783
1784         case FFS_INTERFACE:
1785                 /*
1786                  * Interfaces are indexed from zero so if we
1787                  * encountered interface "n" then there are at least
1788                  * "n+1" interfaces.
1789                  */
1790                 if (*valuep >= ffs->interfaces_count)
1791                         ffs->interfaces_count = *valuep + 1;
1792                 break;
1793
1794         case FFS_STRING:
1795                 /*
1796                  * Strings are indexed from 1 (0 is magic ;) reserved
1797                  * for languages list or some such)
1798                  */
1799                 if (*valuep > ffs->strings_count)
1800                         ffs->strings_count = *valuep;
1801                 break;
1802
1803         case FFS_ENDPOINT:
1804                 /* Endpoints are indexed from 1 as well. */
1805                 if ((*valuep & USB_ENDPOINT_NUMBER_MASK) > ffs->eps_count)
1806                         ffs->eps_count = (*valuep & USB_ENDPOINT_NUMBER_MASK);
1807                 break;
1808         }
1809
1810         return 0;
1811 }
1812
1813 static int __ffs_data_got_descs(struct ffs_data *ffs,
1814                                 char *const _data, size_t len)
1815 {
1816         unsigned fs_count, hs_count;
1817         int fs_len, ret = -EINVAL;
1818         char *data = _data;
1819
1820         ENTER();
1821
1822         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_DESCRIPTORS_MAGIC ||
1823                      get_unaligned_le32(data + 4) != len))
1824                 goto error;
1825         fs_count = get_unaligned_le32(data +  8);
1826         hs_count = get_unaligned_le32(data + 12);
1827
1828         if (!fs_count && !hs_count)
1829                 goto einval;
1830
1831         data += 16;
1832         len  -= 16;
1833
1834         if (likely(fs_count)) {
1835                 fs_len = ffs_do_descs(fs_count, data, len,
1836                                       __ffs_data_do_entity, ffs);
1837                 if (unlikely(fs_len < 0)) {
1838                         ret = fs_len;
1839                         goto error;
1840                 }
1841
1842                 data += fs_len;
1843                 len  -= fs_len;
1844         } else {
1845                 fs_len = 0;
1846         }
1847
1848         if (likely(hs_count)) {
1849                 ret = ffs_do_descs(hs_count, data, len,
1850                                    __ffs_data_do_entity, ffs);
1851                 if (unlikely(ret < 0))
1852                         goto error;
1853         } else {
1854                 ret = 0;
1855         }
1856
1857         if (unlikely(len != ret))
1858                 goto einval;
1859
1860         ffs->raw_fs_descs_length = fs_len;
1861         ffs->raw_descs_length    = fs_len + ret;
1862         ffs->raw_descs           = _data;
1863         ffs->fs_descs_count      = fs_count;
1864         ffs->hs_descs_count      = hs_count;
1865
1866         return 0;
1867
1868 einval:
1869         ret = -EINVAL;
1870 error:
1871         kfree(_data);
1872         return ret;
1873 }
1874
1875 static int __ffs_data_got_strings(struct ffs_data *ffs,
1876                                   char *const _data, size_t len)
1877 {
1878         u32 str_count, needed_count, lang_count;
1879         struct usb_gadget_strings **stringtabs, *t;
1880         struct usb_string *strings, *s;
1881         const char *data = _data;
1882
1883         ENTER();
1884
1885         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
1886                      get_unaligned_le32(data + 4) != len))
1887                 goto error;
1888         str_count  = get_unaligned_le32(data + 8);
1889         lang_count = get_unaligned_le32(data + 12);
1890
1891         /* if one is zero the other must be zero */
1892         if (unlikely(!str_count != !lang_count))
1893                 goto error;
1894
1895         /* Do we have at least as many strings as descriptors need? */
1896         needed_count = ffs->strings_count;
1897         if (unlikely(str_count < needed_count))
1898                 goto error;
1899
1900         /*
1901          * If we don't need any strings just return and free all
1902          * memory.
1903          */
1904         if (!needed_count) {
1905                 kfree(_data);
1906                 return 0;
1907         }
1908
1909         /* Allocate everything in one chunk so there's less maintenance. */
1910         {
1911                 struct {
1912                         struct usb_gadget_strings *stringtabs[lang_count + 1];
1913                         struct usb_gadget_strings stringtab[lang_count];
1914                         struct usb_string strings[lang_count*(needed_count+1)];
1915                 } *d;
1916                 unsigned i = 0;
1917
1918                 d = kmalloc(sizeof *d, GFP_KERNEL);
1919                 if (unlikely(!d)) {
1920                         kfree(_data);
1921                         return -ENOMEM;
1922                 }
1923
1924                 stringtabs = d->stringtabs;
1925                 t = d->stringtab;
1926                 i = lang_count;
1927                 do {
1928                         *stringtabs++ = t++;
1929                 } while (--i);
1930                 *stringtabs = NULL;
1931
1932                 stringtabs = d->stringtabs;
1933                 t = d->stringtab;
1934                 s = d->strings;
1935                 strings = s;
1936         }
1937
1938         /* For each language */
1939         data += 16;
1940         len -= 16;
1941
1942         do { /* lang_count > 0 so we can use do-while */
1943                 unsigned needed = needed_count;
1944
1945                 if (unlikely(len < 3))
1946                         goto error_free;
1947                 t->language = get_unaligned_le16(data);
1948                 t->strings  = s;
1949                 ++t;
1950
1951                 data += 2;
1952                 len -= 2;
1953
1954                 /* For each string */
1955                 do { /* str_count > 0 so we can use do-while */
1956                         size_t length = strnlen(data, len);
1957
1958                         if (unlikely(length == len))
1959                                 goto error_free;
1960
1961                         /*
1962                          * User may provide more strings then we need,
1963                          * if that's the case we simply ignore the
1964                          * rest
1965                          */
1966                         if (likely(needed)) {
1967                                 /*
1968                                  * s->id will be set while adding
1969                                  * function to configuration so for
1970                                  * now just leave garbage here.
1971                                  */
1972                                 s->s = data;
1973                                 --needed;
1974                                 ++s;
1975                         }
1976
1977                         data += length + 1;
1978                         len -= length + 1;
1979                 } while (--str_count);
1980
1981                 s->id = 0;   /* terminator */
1982                 s->s = NULL;
1983                 ++s;
1984
1985         } while (--lang_count);
1986
1987         /* Some garbage left? */
1988         if (unlikely(len))
1989                 goto error_free;
1990
1991         /* Done! */
1992         ffs->stringtabs = stringtabs;
1993         ffs->raw_strings = _data;
1994
1995         return 0;
1996
1997 error_free:
1998         kfree(stringtabs);
1999 error:
2000         kfree(_data);
2001         return -EINVAL;
2002 }
2003
2004
2005 /* Events handling and management *******************************************/
2006
2007 static void __ffs_event_add(struct ffs_data *ffs,
2008                             enum usb_functionfs_event_type type)
2009 {
2010         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2011         int neg = 0;
2012
2013         /*
2014          * Abort any unhandled setup
2015          *
2016          * We do not need to worry about some cmpxchg() changing value
2017          * of ffs->setup_state without holding the lock because when
2018          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2019          * the source does nothing.
2020          */
2021         if (ffs->setup_state == FFS_SETUP_PENDING)
2022                 ffs->setup_state = FFS_SETUP_CANCELED;
2023
2024         switch (type) {
2025         case FUNCTIONFS_RESUME:
2026                 rem_type2 = FUNCTIONFS_SUSPEND;
2027                 /* FALL THROUGH */
2028         case FUNCTIONFS_SUSPEND:
2029         case FUNCTIONFS_SETUP:
2030                 rem_type1 = type;
2031                 /* Discard all similar events */
2032                 break;
2033
2034         case FUNCTIONFS_BIND:
2035         case FUNCTIONFS_UNBIND:
2036         case FUNCTIONFS_DISABLE:
2037         case FUNCTIONFS_ENABLE:
2038                 /* Discard everything other then power management. */
2039                 rem_type1 = FUNCTIONFS_SUSPEND;
2040                 rem_type2 = FUNCTIONFS_RESUME;
2041                 neg = 1;
2042                 break;
2043
2044         default:
2045                 BUG();
2046         }
2047
2048         {
2049                 u8 *ev  = ffs->ev.types, *out = ev;
2050                 unsigned n = ffs->ev.count;
2051                 for (; n; --n, ++ev)
2052                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2053                                 *out++ = *ev;
2054                         else
2055                                 pr_vdebug("purging event %d\n", *ev);
2056                 ffs->ev.count = out - ffs->ev.types;
2057         }
2058
2059         pr_vdebug("adding event %d\n", type);
2060         ffs->ev.types[ffs->ev.count++] = type;
2061         wake_up_locked(&ffs->ev.waitq);
2062 }
2063
2064 static void ffs_event_add(struct ffs_data *ffs,
2065                           enum usb_functionfs_event_type type)
2066 {
2067         unsigned long flags;
2068         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2069         __ffs_event_add(ffs, type);
2070         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2071 }
2072
2073
2074 /* Bind/unbind USB function hooks *******************************************/
2075
2076 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2077                                     struct usb_descriptor_header *desc,
2078                                     void *priv)
2079 {
2080         struct usb_endpoint_descriptor *ds = (void *)desc;
2081         struct ffs_function *func = priv;
2082         struct ffs_ep *ffs_ep;
2083
2084         /*
2085          * If hs_descriptors is not NULL then we are reading hs
2086          * descriptors now
2087          */
2088         const int isHS = func->function.hs_descriptors != NULL;
2089         unsigned idx;
2090
2091         if (type != FFS_DESCRIPTOR)
2092                 return 0;
2093
2094         if (isHS)
2095                 func->function.hs_descriptors[(long)valuep] = desc;
2096         else
2097                 func->function.fs_descriptors[(long)valuep]    = desc;
2098
2099         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2100                 return 0;
2101
2102         idx = (ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK) - 1;
2103         ffs_ep = func->eps + idx;
2104
2105         if (unlikely(ffs_ep->descs[isHS])) {
2106                 pr_vdebug("two %sspeed descriptors for EP %d\n",
2107                           isHS ? "high" : "full",
2108                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2109                 return -EINVAL;
2110         }
2111         ffs_ep->descs[isHS] = ds;
2112
2113         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2114         if (ffs_ep->ep) {
2115                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2116                 if (!ds->wMaxPacketSize)
2117                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2118         } else {
2119                 struct usb_request *req;
2120                 struct usb_ep *ep;
2121
2122                 pr_vdebug("autoconfig\n");
2123                 ep = usb_ep_autoconfig(func->gadget, ds);
2124                 if (unlikely(!ep))
2125                         return -ENOTSUPP;
2126                 ep->driver_data = func->eps + idx;
2127
2128                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2129                 if (unlikely(!req))
2130                         return -ENOMEM;
2131
2132                 ffs_ep->ep  = ep;
2133                 ffs_ep->req = req;
2134                 func->eps_revmap[ds->bEndpointAddress &
2135                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2136         }
2137         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2138
2139         return 0;
2140 }
2141
2142 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2143                                    struct usb_descriptor_header *desc,
2144                                    void *priv)
2145 {
2146         struct ffs_function *func = priv;
2147         unsigned idx;
2148         u8 newValue;
2149
2150         switch (type) {
2151         default:
2152         case FFS_DESCRIPTOR:
2153                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2154                 return 0;
2155
2156         case FFS_INTERFACE:
2157                 idx = *valuep;
2158                 if (func->interfaces_nums[idx] < 0) {
2159                         int id = usb_interface_id(func->conf, &func->function);
2160                         if (unlikely(id < 0))
2161                                 return id;
2162                         func->interfaces_nums[idx] = id;
2163                 }
2164                 newValue = func->interfaces_nums[idx];
2165                 break;
2166
2167         case FFS_STRING:
2168                 /* String' IDs are allocated when fsf_data is bound to cdev */
2169                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2170                 break;
2171
2172         case FFS_ENDPOINT:
2173                 /*
2174                  * USB_DT_ENDPOINT are handled in
2175                  * __ffs_func_bind_do_descs().
2176                  */
2177                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2178                         return 0;
2179
2180                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2181                 if (unlikely(!func->eps[idx].ep))
2182                         return -EINVAL;
2183
2184                 {
2185                         struct usb_endpoint_descriptor **descs;
2186                         descs = func->eps[idx].descs;
2187                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2188                 }
2189                 break;
2190         }
2191
2192         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2193         *valuep = newValue;
2194         return 0;
2195 }
2196
2197 static int ffs_func_bind(struct usb_configuration *c,
2198                          struct usb_function *f)
2199 {
2200         struct ffs_function *func = ffs_func_from_usb(f);
2201         struct ffs_data *ffs = func->ffs;
2202
2203         const int full = !!func->ffs->fs_descs_count;
2204         const int high = gadget_is_dualspeed(func->gadget) &&
2205                 func->ffs->hs_descs_count;
2206
2207         int ret;
2208
2209         /* Make it a single chunk, less management later on */
2210         struct {
2211                 struct ffs_ep eps[ffs->eps_count];
2212                 struct usb_descriptor_header
2213                         *fs_descs[full ? ffs->fs_descs_count + 1 : 0];
2214                 struct usb_descriptor_header
2215                         *hs_descs[high ? ffs->hs_descs_count + 1 : 0];
2216                 short inums[ffs->interfaces_count];
2217                 char raw_descs[high ? ffs->raw_descs_length
2218                                     : ffs->raw_fs_descs_length];
2219         } *data;
2220
2221         ENTER();
2222
2223         /* Only high speed but not supported by gadget? */
2224         if (unlikely(!(full | high)))
2225                 return -ENOTSUPP;
2226
2227         /* Allocate */
2228         data = kmalloc(sizeof *data, GFP_KERNEL);
2229         if (unlikely(!data))
2230                 return -ENOMEM;
2231
2232         /* Zero */
2233         memset(data->eps, 0, sizeof data->eps);
2234         memcpy(data->raw_descs, ffs->raw_descs + 16, sizeof data->raw_descs);
2235         memset(data->inums, 0xff, sizeof data->inums);
2236         for (ret = ffs->eps_count; ret; --ret)
2237                 data->eps[ret].num = -1;
2238
2239         /* Save pointers */
2240         func->eps             = data->eps;
2241         func->interfaces_nums = data->inums;
2242
2243         /*
2244          * Go through all the endpoint descriptors and allocate
2245          * endpoints first, so that later we can rewrite the endpoint
2246          * numbers without worrying that it may be described later on.
2247          */
2248         if (likely(full)) {
2249                 func->function.fs_descriptors = data->fs_descs;
2250                 ret = ffs_do_descs(ffs->fs_descs_count,
2251                                    data->raw_descs,
2252                                    sizeof data->raw_descs,
2253                                    __ffs_func_bind_do_descs, func);
2254                 if (unlikely(ret < 0))
2255                         goto error;
2256         } else {
2257                 ret = 0;
2258         }
2259
2260         if (likely(high)) {
2261                 func->function.hs_descriptors = data->hs_descs;
2262                 ret = ffs_do_descs(ffs->hs_descs_count,
2263                                    data->raw_descs + ret,
2264                                    (sizeof data->raw_descs) - ret,
2265                                    __ffs_func_bind_do_descs, func);
2266         }
2267
2268         /*
2269          * Now handle interface numbers allocation and interface and
2270          * endpoint numbers rewriting.  We can do that in one go
2271          * now.
2272          */
2273         ret = ffs_do_descs(ffs->fs_descs_count +
2274                            (high ? ffs->hs_descs_count : 0),
2275                            data->raw_descs, sizeof data->raw_descs,
2276                            __ffs_func_bind_do_nums, func);
2277         if (unlikely(ret < 0))
2278                 goto error;
2279
2280         /* And we're done */
2281         ffs_event_add(ffs, FUNCTIONFS_BIND);
2282         return 0;
2283
2284 error:
2285         /* XXX Do we need to release all claimed endpoints here? */
2286         return ret;
2287 }
2288
2289
2290 /* Other USB function hooks *************************************************/
2291
2292 static void ffs_func_unbind(struct usb_configuration *c,
2293                             struct usb_function *f)
2294 {
2295         struct ffs_function *func = ffs_func_from_usb(f);
2296         struct ffs_data *ffs = func->ffs;
2297
2298         ENTER();
2299
2300         if (ffs->func == func) {
2301                 ffs_func_eps_disable(func);
2302                 ffs->func = NULL;
2303         }
2304
2305         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
2306
2307         ffs_func_free(func);
2308 }
2309
2310 static int ffs_func_set_alt(struct usb_function *f,
2311                             unsigned interface, unsigned alt)
2312 {
2313         struct ffs_function *func = ffs_func_from_usb(f);
2314         struct ffs_data *ffs = func->ffs;
2315         int ret = 0, intf;
2316
2317         if (alt != (unsigned)-1) {
2318                 intf = ffs_func_revmap_intf(func, interface);
2319                 if (unlikely(intf < 0))
2320                         return intf;
2321         }
2322
2323         if (ffs->func)
2324                 ffs_func_eps_disable(ffs->func);
2325
2326         if (ffs->state != FFS_ACTIVE)
2327                 return -ENODEV;
2328
2329         if (alt == (unsigned)-1) {
2330                 ffs->func = NULL;
2331                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2332                 return 0;
2333         }
2334
2335         ffs->func = func;
2336         ret = ffs_func_eps_enable(func);
2337         if (likely(ret >= 0))
2338                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2339         return ret;
2340 }
2341
2342 static void ffs_func_disable(struct usb_function *f)
2343 {
2344         ffs_func_set_alt(f, 0, (unsigned)-1);
2345 }
2346
2347 static int ffs_func_setup(struct usb_function *f,
2348                           const struct usb_ctrlrequest *creq)
2349 {
2350         struct ffs_function *func = ffs_func_from_usb(f);
2351         struct ffs_data *ffs = func->ffs;
2352         unsigned long flags;
2353         int ret;
2354
2355         ENTER();
2356
2357         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2358         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2359         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2360         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
2361         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
2362
2363         /*
2364          * Most requests directed to interface go through here
2365          * (notable exceptions are set/get interface) so we need to
2366          * handle them.  All other either handled by composite or
2367          * passed to usb_configuration->setup() (if one is set).  No
2368          * matter, we will handle requests directed to endpoint here
2369          * as well (as it's straightforward) but what to do with any
2370          * other request?
2371          */
2372         if (ffs->state != FFS_ACTIVE)
2373                 return -ENODEV;
2374
2375         switch (creq->bRequestType & USB_RECIP_MASK) {
2376         case USB_RECIP_INTERFACE:
2377                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
2378                 if (unlikely(ret < 0))
2379                         return ret;
2380                 break;
2381
2382         case USB_RECIP_ENDPOINT:
2383                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
2384                 if (unlikely(ret < 0))
2385                         return ret;
2386                 break;
2387
2388         default:
2389                 return -EOPNOTSUPP;
2390         }
2391
2392         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2393         ffs->ev.setup = *creq;
2394         ffs->ev.setup.wIndex = cpu_to_le16(ret);
2395         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
2396         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2397
2398         return 0;
2399 }
2400
2401 static void ffs_func_suspend(struct usb_function *f)
2402 {
2403         ENTER();
2404         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
2405 }
2406
2407 static void ffs_func_resume(struct usb_function *f)
2408 {
2409         ENTER();
2410         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
2411 }
2412
2413
2414 /* Endpoint and interface numbers reverse mapping ***************************/
2415
2416 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
2417 {
2418         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
2419         return num ? num : -EDOM;
2420 }
2421
2422 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
2423 {
2424         short *nums = func->interfaces_nums;
2425         unsigned count = func->ffs->interfaces_count;
2426
2427         for (; count; --count, ++nums) {
2428                 if (*nums >= 0 && *nums == intf)
2429                         return nums - func->interfaces_nums;
2430         }
2431
2432         return -EDOM;
2433 }
2434
2435
2436 /* Misc helper functions ****************************************************/
2437
2438 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
2439 {
2440         return nonblock
2441                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
2442                 : mutex_lock_interruptible(mutex);
2443 }
2444
2445 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
2446 {
2447         char *data;
2448
2449         if (unlikely(!len))
2450                 return NULL;
2451
2452         data = kmalloc(len, GFP_KERNEL);
2453         if (unlikely(!data))
2454                 return ERR_PTR(-ENOMEM);
2455
2456         if (unlikely(__copy_from_user(data, buf, len))) {
2457                 kfree(data);
2458                 return ERR_PTR(-EFAULT);
2459         }
2460
2461         pr_vdebug("Buffer from user space:\n");
2462         ffs_dump_mem("", data, len);
2463
2464         return data;
2465 }