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         .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 = make_kuid(current_user_ns(), value);
1152                                 if (!uid_valid(data->perms.uid)) {
1153                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1154                                         return -EINVAL;
1155                                 }
1156                         }
1157                         else if (!memcmp(opts, "gid", 3))
1158                                 data->perms.gid = make_kgid(current_user_ns(), value);
1159                                 if (!gid_valid(data->perms.gid)) {
1160                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1161                                         return -EINVAL;
1162                                 }
1163                         else
1164                                 goto invalid;
1165                         break;
1166
1167                 default:
1168 invalid:
1169                         pr_err("%s: invalid option\n", opts);
1170                         return -EINVAL;
1171                 }
1172
1173                 /* Next iteration */
1174                 if (!comma)
1175                         break;
1176                 opts = comma + 1;
1177         }
1178
1179         return 0;
1180 }
1181
1182 /* "mount -t functionfs dev_name /dev/function" ends up here */
1183
1184 static struct dentry *
1185 ffs_fs_mount(struct file_system_type *t, int flags,
1186               const char *dev_name, void *opts)
1187 {
1188         struct ffs_sb_fill_data data = {
1189                 .perms = {
1190                         .mode = S_IFREG | 0600,
1191                         .uid = GLOBAL_ROOT_UID,
1192                         .gid = GLOBAL_ROOT_GID,
1193                 },
1194                 .root_mode = S_IFDIR | 0500,
1195         };
1196         struct dentry *rv;
1197         int ret;
1198         void *ffs_dev;
1199
1200         ENTER();
1201
1202         ret = ffs_fs_parse_opts(&data, opts);
1203         if (unlikely(ret < 0))
1204                 return ERR_PTR(ret);
1205
1206         ffs_dev = functionfs_acquire_dev_callback(dev_name);
1207         if (IS_ERR(ffs_dev))
1208                 return ffs_dev;
1209
1210         data.dev_name = dev_name;
1211         data.private_data = ffs_dev;
1212         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1213
1214         /* data.ffs_data is set by ffs_sb_fill */
1215         if (IS_ERR(rv))
1216                 functionfs_release_dev_callback(data.ffs_data);
1217
1218         return rv;
1219 }
1220
1221 static void
1222 ffs_fs_kill_sb(struct super_block *sb)
1223 {
1224         ENTER();
1225
1226         kill_litter_super(sb);
1227         if (sb->s_fs_info) {
1228                 functionfs_release_dev_callback(sb->s_fs_info);
1229                 ffs_data_put(sb->s_fs_info);
1230         }
1231 }
1232
1233 static struct file_system_type ffs_fs_type = {
1234         .owner          = THIS_MODULE,
1235         .name           = "functionfs",
1236         .mount          = ffs_fs_mount,
1237         .kill_sb        = ffs_fs_kill_sb,
1238 };
1239
1240
1241 /* Driver's main init/cleanup functions *************************************/
1242
1243 static int functionfs_init(void)
1244 {
1245         int ret;
1246
1247         ENTER();
1248
1249         ret = register_filesystem(&ffs_fs_type);
1250         if (likely(!ret))
1251                 pr_info("file system registered\n");
1252         else
1253                 pr_err("failed registering file system (%d)\n", ret);
1254
1255         return ret;
1256 }
1257
1258 static void functionfs_cleanup(void)
1259 {
1260         ENTER();
1261
1262         pr_info("unloading\n");
1263         unregister_filesystem(&ffs_fs_type);
1264 }
1265
1266
1267 /* ffs_data and ffs_function construction and destruction code **************/
1268
1269 static void ffs_data_clear(struct ffs_data *ffs);
1270 static void ffs_data_reset(struct ffs_data *ffs);
1271
1272 static void ffs_data_get(struct ffs_data *ffs)
1273 {
1274         ENTER();
1275
1276         atomic_inc(&ffs->ref);
1277 }
1278
1279 static void ffs_data_opened(struct ffs_data *ffs)
1280 {
1281         ENTER();
1282
1283         atomic_inc(&ffs->ref);
1284         atomic_inc(&ffs->opened);
1285 }
1286
1287 static void ffs_data_put(struct ffs_data *ffs)
1288 {
1289         ENTER();
1290
1291         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1292                 pr_info("%s(): freeing\n", __func__);
1293                 ffs_data_clear(ffs);
1294                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1295                        waitqueue_active(&ffs->ep0req_completion.wait));
1296                 kfree(ffs->dev_name);
1297                 kfree(ffs);
1298         }
1299 }
1300
1301 static void ffs_data_closed(struct ffs_data *ffs)
1302 {
1303         ENTER();
1304
1305         if (atomic_dec_and_test(&ffs->opened)) {
1306                 ffs->state = FFS_CLOSING;
1307                 ffs_data_reset(ffs);
1308         }
1309
1310         ffs_data_put(ffs);
1311 }
1312
1313 static struct ffs_data *ffs_data_new(void)
1314 {
1315         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1316         if (unlikely(!ffs))
1317                 return 0;
1318
1319         ENTER();
1320
1321         atomic_set(&ffs->ref, 1);
1322         atomic_set(&ffs->opened, 0);
1323         ffs->state = FFS_READ_DESCRIPTORS;
1324         mutex_init(&ffs->mutex);
1325         spin_lock_init(&ffs->eps_lock);
1326         init_waitqueue_head(&ffs->ev.waitq);
1327         init_completion(&ffs->ep0req_completion);
1328
1329         /* XXX REVISIT need to update it in some places, or do we? */
1330         ffs->ev.can_stall = 1;
1331
1332         return ffs;
1333 }
1334
1335 static void ffs_data_clear(struct ffs_data *ffs)
1336 {
1337         ENTER();
1338
1339         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags))
1340                 functionfs_closed_callback(ffs);
1341
1342         BUG_ON(ffs->gadget);
1343
1344         if (ffs->epfiles)
1345                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1346
1347         kfree(ffs->raw_descs);
1348         kfree(ffs->raw_strings);
1349         kfree(ffs->stringtabs);
1350 }
1351
1352 static void ffs_data_reset(struct ffs_data *ffs)
1353 {
1354         ENTER();
1355
1356         ffs_data_clear(ffs);
1357
1358         ffs->epfiles = NULL;
1359         ffs->raw_descs = NULL;
1360         ffs->raw_strings = NULL;
1361         ffs->stringtabs = NULL;
1362
1363         ffs->raw_descs_length = 0;
1364         ffs->raw_fs_descs_length = 0;
1365         ffs->fs_descs_count = 0;
1366         ffs->hs_descs_count = 0;
1367
1368         ffs->strings_count = 0;
1369         ffs->interfaces_count = 0;
1370         ffs->eps_count = 0;
1371
1372         ffs->ev.count = 0;
1373
1374         ffs->state = FFS_READ_DESCRIPTORS;
1375         ffs->setup_state = FFS_NO_SETUP;
1376         ffs->flags = 0;
1377 }
1378
1379
1380 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1381 {
1382         struct usb_gadget_strings **lang;
1383         int first_id;
1384
1385         ENTER();
1386
1387         if (WARN_ON(ffs->state != FFS_ACTIVE
1388                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1389                 return -EBADFD;
1390
1391         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1392         if (unlikely(first_id < 0))
1393                 return first_id;
1394
1395         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1396         if (unlikely(!ffs->ep0req))
1397                 return -ENOMEM;
1398         ffs->ep0req->complete = ffs_ep0_complete;
1399         ffs->ep0req->context = ffs;
1400
1401         lang = ffs->stringtabs;
1402         for (lang = ffs->stringtabs; *lang; ++lang) {
1403                 struct usb_string *str = (*lang)->strings;
1404                 int id = first_id;
1405                 for (; str->s; ++id, ++str)
1406                         str->id = id;
1407         }
1408
1409         ffs->gadget = cdev->gadget;
1410         ffs_data_get(ffs);
1411         return 0;
1412 }
1413
1414 static void functionfs_unbind(struct ffs_data *ffs)
1415 {
1416         ENTER();
1417
1418         if (!WARN_ON(!ffs->gadget)) {
1419                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1420                 ffs->ep0req = NULL;
1421                 ffs->gadget = NULL;
1422                 ffs_data_put(ffs);
1423                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1424         }
1425 }
1426
1427 static int ffs_epfiles_create(struct ffs_data *ffs)
1428 {
1429         struct ffs_epfile *epfile, *epfiles;
1430         unsigned i, count;
1431
1432         ENTER();
1433
1434         count = ffs->eps_count;
1435         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1436         if (!epfiles)
1437                 return -ENOMEM;
1438
1439         epfile = epfiles;
1440         for (i = 1; i <= count; ++i, ++epfile) {
1441                 epfile->ffs = ffs;
1442                 mutex_init(&epfile->mutex);
1443                 init_waitqueue_head(&epfile->wait);
1444                 sprintf(epfiles->name, "ep%u",  i);
1445                 if (!unlikely(ffs_sb_create_file(ffs->sb, epfiles->name, epfile,
1446                                                  &ffs_epfile_operations,
1447                                                  &epfile->dentry))) {
1448                         ffs_epfiles_destroy(epfiles, i - 1);
1449                         return -ENOMEM;
1450                 }
1451         }
1452
1453         ffs->epfiles = epfiles;
1454         return 0;
1455 }
1456
1457 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1458 {
1459         struct ffs_epfile *epfile = epfiles;
1460
1461         ENTER();
1462
1463         for (; count; --count, ++epfile) {
1464                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1465                        waitqueue_active(&epfile->wait));
1466                 if (epfile->dentry) {
1467                         d_delete(epfile->dentry);
1468                         dput(epfile->dentry);
1469                         epfile->dentry = NULL;
1470                 }
1471         }
1472
1473         kfree(epfiles);
1474 }
1475
1476 static int functionfs_bind_config(struct usb_composite_dev *cdev,
1477                                   struct usb_configuration *c,
1478                                   struct ffs_data *ffs)
1479 {
1480         struct ffs_function *func;
1481         int ret;
1482
1483         ENTER();
1484
1485         func = kzalloc(sizeof *func, GFP_KERNEL);
1486         if (unlikely(!func))
1487                 return -ENOMEM;
1488
1489         func->function.name    = "Function FS Gadget";
1490         func->function.strings = ffs->stringtabs;
1491
1492         func->function.bind    = ffs_func_bind;
1493         func->function.unbind  = ffs_func_unbind;
1494         func->function.set_alt = ffs_func_set_alt;
1495         func->function.disable = ffs_func_disable;
1496         func->function.setup   = ffs_func_setup;
1497         func->function.suspend = ffs_func_suspend;
1498         func->function.resume  = ffs_func_resume;
1499
1500         func->conf   = c;
1501         func->gadget = cdev->gadget;
1502         func->ffs = ffs;
1503         ffs_data_get(ffs);
1504
1505         ret = usb_add_function(c, &func->function);
1506         if (unlikely(ret))
1507                 ffs_func_free(func);
1508
1509         return ret;
1510 }
1511
1512 static void ffs_func_free(struct ffs_function *func)
1513 {
1514         struct ffs_ep *ep         = func->eps;
1515         unsigned count            = func->ffs->eps_count;
1516         unsigned long flags;
1517
1518         ENTER();
1519
1520         /* cleanup after autoconfig */
1521         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1522         do {
1523                 if (ep->ep && ep->req)
1524                         usb_ep_free_request(ep->ep, ep->req);
1525                 ep->req = NULL;
1526                 ++ep;
1527         } while (--count);
1528         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1529
1530         ffs_data_put(func->ffs);
1531
1532         kfree(func->eps);
1533         /*
1534          * eps and interfaces_nums are allocated in the same chunk so
1535          * only one free is required.  Descriptors are also allocated
1536          * in the same chunk.
1537          */
1538
1539         kfree(func);
1540 }
1541
1542 static void ffs_func_eps_disable(struct ffs_function *func)
1543 {
1544         struct ffs_ep *ep         = func->eps;
1545         struct ffs_epfile *epfile = func->ffs->epfiles;
1546         unsigned count            = func->ffs->eps_count;
1547         unsigned long flags;
1548
1549         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1550         do {
1551                 /* pending requests get nuked */
1552                 if (likely(ep->ep))
1553                         usb_ep_disable(ep->ep);
1554                 epfile->ep = NULL;
1555
1556                 ++ep;
1557                 ++epfile;
1558         } while (--count);
1559         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1560 }
1561
1562 static int ffs_func_eps_enable(struct ffs_function *func)
1563 {
1564         struct ffs_data *ffs      = func->ffs;
1565         struct ffs_ep *ep         = func->eps;
1566         struct ffs_epfile *epfile = ffs->epfiles;
1567         unsigned count            = ffs->eps_count;
1568         unsigned long flags;
1569         int ret = 0;
1570
1571         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1572         do {
1573                 struct usb_endpoint_descriptor *ds;
1574                 ds = ep->descs[ep->descs[1] ? 1 : 0];
1575
1576                 ep->ep->driver_data = ep;
1577                 ep->ep->desc = ds;
1578                 ret = usb_ep_enable(ep->ep);
1579                 if (likely(!ret)) {
1580                         epfile->ep = ep;
1581                         epfile->in = usb_endpoint_dir_in(ds);
1582                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1583                 } else {
1584                         break;
1585                 }
1586
1587                 wake_up(&epfile->wait);
1588
1589                 ++ep;
1590                 ++epfile;
1591         } while (--count);
1592         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1593
1594         return ret;
1595 }
1596
1597
1598 /* Parsing and building descriptors and strings *****************************/
1599
1600 /*
1601  * This validates if data pointed by data is a valid USB descriptor as
1602  * well as record how many interfaces, endpoints and strings are
1603  * required by given configuration.  Returns address after the
1604  * descriptor or NULL if data is invalid.
1605  */
1606
1607 enum ffs_entity_type {
1608         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1609 };
1610
1611 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1612                                    u8 *valuep,
1613                                    struct usb_descriptor_header *desc,
1614                                    void *priv);
1615
1616 static int __must_check ffs_do_desc(char *data, unsigned len,
1617                                     ffs_entity_callback entity, void *priv)
1618 {
1619         struct usb_descriptor_header *_ds = (void *)data;
1620         u8 length;
1621         int ret;
1622
1623         ENTER();
1624
1625         /* At least two bytes are required: length and type */
1626         if (len < 2) {
1627                 pr_vdebug("descriptor too short\n");
1628                 return -EINVAL;
1629         }
1630
1631         /* If we have at least as many bytes as the descriptor takes? */
1632         length = _ds->bLength;
1633         if (len < length) {
1634                 pr_vdebug("descriptor longer then available data\n");
1635                 return -EINVAL;
1636         }
1637
1638 #define __entity_check_INTERFACE(val)  1
1639 #define __entity_check_STRING(val)     (val)
1640 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1641 #define __entity(type, val) do {                                        \
1642                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1643                 if (unlikely(!__entity_check_ ##type(val))) {           \
1644                         pr_vdebug("invalid entity's value\n");          \
1645                         return -EINVAL;                                 \
1646                 }                                                       \
1647                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1648                 if (unlikely(ret < 0)) {                                \
1649                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1650                                  (val), ret);                           \
1651                         return ret;                                     \
1652                 }                                                       \
1653         } while (0)
1654
1655         /* Parse descriptor depending on type. */
1656         switch (_ds->bDescriptorType) {
1657         case USB_DT_DEVICE:
1658         case USB_DT_CONFIG:
1659         case USB_DT_STRING:
1660         case USB_DT_DEVICE_QUALIFIER:
1661                 /* function can't have any of those */
1662                 pr_vdebug("descriptor reserved for gadget: %d\n",
1663                       _ds->bDescriptorType);
1664                 return -EINVAL;
1665
1666         case USB_DT_INTERFACE: {
1667                 struct usb_interface_descriptor *ds = (void *)_ds;
1668                 pr_vdebug("interface descriptor\n");
1669                 if (length != sizeof *ds)
1670                         goto inv_length;
1671
1672                 __entity(INTERFACE, ds->bInterfaceNumber);
1673                 if (ds->iInterface)
1674                         __entity(STRING, ds->iInterface);
1675         }
1676                 break;
1677
1678         case USB_DT_ENDPOINT: {
1679                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1680                 pr_vdebug("endpoint descriptor\n");
1681                 if (length != USB_DT_ENDPOINT_SIZE &&
1682                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1683                         goto inv_length;
1684                 __entity(ENDPOINT, ds->bEndpointAddress);
1685         }
1686                 break;
1687
1688         case HID_DT_HID:
1689                 pr_vdebug("hid descriptor\n");
1690                 if (length != sizeof(struct hid_descriptor))
1691                         goto inv_length;
1692                 break;
1693
1694         case USB_DT_OTG:
1695                 if (length != sizeof(struct usb_otg_descriptor))
1696                         goto inv_length;
1697                 break;
1698
1699         case USB_DT_INTERFACE_ASSOCIATION: {
1700                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1701                 pr_vdebug("interface association descriptor\n");
1702                 if (length != sizeof *ds)
1703                         goto inv_length;
1704                 if (ds->iFunction)
1705                         __entity(STRING, ds->iFunction);
1706         }
1707                 break;
1708
1709         case USB_DT_OTHER_SPEED_CONFIG:
1710         case USB_DT_INTERFACE_POWER:
1711         case USB_DT_DEBUG:
1712         case USB_DT_SECURITY:
1713         case USB_DT_CS_RADIO_CONTROL:
1714                 /* TODO */
1715                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1716                 return -EINVAL;
1717
1718         default:
1719                 /* We should never be here */
1720                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1721                 return -EINVAL;
1722
1723 inv_length:
1724                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1725                           _ds->bLength, _ds->bDescriptorType);
1726                 return -EINVAL;
1727         }
1728
1729 #undef __entity
1730 #undef __entity_check_DESCRIPTOR
1731 #undef __entity_check_INTERFACE
1732 #undef __entity_check_STRING
1733 #undef __entity_check_ENDPOINT
1734
1735         return length;
1736 }
1737
1738 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1739                                      ffs_entity_callback entity, void *priv)
1740 {
1741         const unsigned _len = len;
1742         unsigned long num = 0;
1743
1744         ENTER();
1745
1746         for (;;) {
1747                 int ret;
1748
1749                 if (num == count)
1750                         data = NULL;
1751
1752                 /* Record "descriptor" entity */
1753                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1754                 if (unlikely(ret < 0)) {
1755                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1756                                  num, ret);
1757                         return ret;
1758                 }
1759
1760                 if (!data)
1761                         return _len - len;
1762
1763                 ret = ffs_do_desc(data, len, entity, priv);
1764                 if (unlikely(ret < 0)) {
1765                         pr_debug("%s returns %d\n", __func__, ret);
1766                         return ret;
1767                 }
1768
1769                 len -= ret;
1770                 data += ret;
1771                 ++num;
1772         }
1773 }
1774
1775 static int __ffs_data_do_entity(enum ffs_entity_type type,
1776                                 u8 *valuep, struct usb_descriptor_header *desc,
1777                                 void *priv)
1778 {
1779         struct ffs_data *ffs = priv;
1780
1781         ENTER();
1782
1783         switch (type) {
1784         case FFS_DESCRIPTOR:
1785                 break;
1786
1787         case FFS_INTERFACE:
1788                 /*
1789                  * Interfaces are indexed from zero so if we
1790                  * encountered interface "n" then there are at least
1791                  * "n+1" interfaces.
1792                  */
1793                 if (*valuep >= ffs->interfaces_count)
1794                         ffs->interfaces_count = *valuep + 1;
1795                 break;
1796
1797         case FFS_STRING:
1798                 /*
1799                  * Strings are indexed from 1 (0 is magic ;) reserved
1800                  * for languages list or some such)
1801                  */
1802                 if (*valuep > ffs->strings_count)
1803                         ffs->strings_count = *valuep;
1804                 break;
1805
1806         case FFS_ENDPOINT:
1807                 /* Endpoints are indexed from 1 as well. */
1808                 if ((*valuep & USB_ENDPOINT_NUMBER_MASK) > ffs->eps_count)
1809                         ffs->eps_count = (*valuep & USB_ENDPOINT_NUMBER_MASK);
1810                 break;
1811         }
1812
1813         return 0;
1814 }
1815
1816 static int __ffs_data_got_descs(struct ffs_data *ffs,
1817                                 char *const _data, size_t len)
1818 {
1819         unsigned fs_count, hs_count;
1820         int fs_len, ret = -EINVAL;
1821         char *data = _data;
1822
1823         ENTER();
1824
1825         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_DESCRIPTORS_MAGIC ||
1826                      get_unaligned_le32(data + 4) != len))
1827                 goto error;
1828         fs_count = get_unaligned_le32(data +  8);
1829         hs_count = get_unaligned_le32(data + 12);
1830
1831         if (!fs_count && !hs_count)
1832                 goto einval;
1833
1834         data += 16;
1835         len  -= 16;
1836
1837         if (likely(fs_count)) {
1838                 fs_len = ffs_do_descs(fs_count, data, len,
1839                                       __ffs_data_do_entity, ffs);
1840                 if (unlikely(fs_len < 0)) {
1841                         ret = fs_len;
1842                         goto error;
1843                 }
1844
1845                 data += fs_len;
1846                 len  -= fs_len;
1847         } else {
1848                 fs_len = 0;
1849         }
1850
1851         if (likely(hs_count)) {
1852                 ret = ffs_do_descs(hs_count, data, len,
1853                                    __ffs_data_do_entity, ffs);
1854                 if (unlikely(ret < 0))
1855                         goto error;
1856         } else {
1857                 ret = 0;
1858         }
1859
1860         if (unlikely(len != ret))
1861                 goto einval;
1862
1863         ffs->raw_fs_descs_length = fs_len;
1864         ffs->raw_descs_length    = fs_len + ret;
1865         ffs->raw_descs           = _data;
1866         ffs->fs_descs_count      = fs_count;
1867         ffs->hs_descs_count      = hs_count;
1868
1869         return 0;
1870
1871 einval:
1872         ret = -EINVAL;
1873 error:
1874         kfree(_data);
1875         return ret;
1876 }
1877
1878 static int __ffs_data_got_strings(struct ffs_data *ffs,
1879                                   char *const _data, size_t len)
1880 {
1881         u32 str_count, needed_count, lang_count;
1882         struct usb_gadget_strings **stringtabs, *t;
1883         struct usb_string *strings, *s;
1884         const char *data = _data;
1885
1886         ENTER();
1887
1888         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
1889                      get_unaligned_le32(data + 4) != len))
1890                 goto error;
1891         str_count  = get_unaligned_le32(data + 8);
1892         lang_count = get_unaligned_le32(data + 12);
1893
1894         /* if one is zero the other must be zero */
1895         if (unlikely(!str_count != !lang_count))
1896                 goto error;
1897
1898         /* Do we have at least as many strings as descriptors need? */
1899         needed_count = ffs->strings_count;
1900         if (unlikely(str_count < needed_count))
1901                 goto error;
1902
1903         /*
1904          * If we don't need any strings just return and free all
1905          * memory.
1906          */
1907         if (!needed_count) {
1908                 kfree(_data);
1909                 return 0;
1910         }
1911
1912         /* Allocate everything in one chunk so there's less maintenance. */
1913         {
1914                 struct {
1915                         struct usb_gadget_strings *stringtabs[lang_count + 1];
1916                         struct usb_gadget_strings stringtab[lang_count];
1917                         struct usb_string strings[lang_count*(needed_count+1)];
1918                 } *d;
1919                 unsigned i = 0;
1920
1921                 d = kmalloc(sizeof *d, GFP_KERNEL);
1922                 if (unlikely(!d)) {
1923                         kfree(_data);
1924                         return -ENOMEM;
1925                 }
1926
1927                 stringtabs = d->stringtabs;
1928                 t = d->stringtab;
1929                 i = lang_count;
1930                 do {
1931                         *stringtabs++ = t++;
1932                 } while (--i);
1933                 *stringtabs = NULL;
1934
1935                 stringtabs = d->stringtabs;
1936                 t = d->stringtab;
1937                 s = d->strings;
1938                 strings = s;
1939         }
1940
1941         /* For each language */
1942         data += 16;
1943         len -= 16;
1944
1945         do { /* lang_count > 0 so we can use do-while */
1946                 unsigned needed = needed_count;
1947
1948                 if (unlikely(len < 3))
1949                         goto error_free;
1950                 t->language = get_unaligned_le16(data);
1951                 t->strings  = s;
1952                 ++t;
1953
1954                 data += 2;
1955                 len -= 2;
1956
1957                 /* For each string */
1958                 do { /* str_count > 0 so we can use do-while */
1959                         size_t length = strnlen(data, len);
1960
1961                         if (unlikely(length == len))
1962                                 goto error_free;
1963
1964                         /*
1965                          * User may provide more strings then we need,
1966                          * if that's the case we simply ignore the
1967                          * rest
1968                          */
1969                         if (likely(needed)) {
1970                                 /*
1971                                  * s->id will be set while adding
1972                                  * function to configuration so for
1973                                  * now just leave garbage here.
1974                                  */
1975                                 s->s = data;
1976                                 --needed;
1977                                 ++s;
1978                         }
1979
1980                         data += length + 1;
1981                         len -= length + 1;
1982                 } while (--str_count);
1983
1984                 s->id = 0;   /* terminator */
1985                 s->s = NULL;
1986                 ++s;
1987
1988         } while (--lang_count);
1989
1990         /* Some garbage left? */
1991         if (unlikely(len))
1992                 goto error_free;
1993
1994         /* Done! */
1995         ffs->stringtabs = stringtabs;
1996         ffs->raw_strings = _data;
1997
1998         return 0;
1999
2000 error_free:
2001         kfree(stringtabs);
2002 error:
2003         kfree(_data);
2004         return -EINVAL;
2005 }
2006
2007
2008 /* Events handling and management *******************************************/
2009
2010 static void __ffs_event_add(struct ffs_data *ffs,
2011                             enum usb_functionfs_event_type type)
2012 {
2013         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2014         int neg = 0;
2015
2016         /*
2017          * Abort any unhandled setup
2018          *
2019          * We do not need to worry about some cmpxchg() changing value
2020          * of ffs->setup_state without holding the lock because when
2021          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2022          * the source does nothing.
2023          */
2024         if (ffs->setup_state == FFS_SETUP_PENDING)
2025                 ffs->setup_state = FFS_SETUP_CANCELED;
2026
2027         switch (type) {
2028         case FUNCTIONFS_RESUME:
2029                 rem_type2 = FUNCTIONFS_SUSPEND;
2030                 /* FALL THROUGH */
2031         case FUNCTIONFS_SUSPEND:
2032         case FUNCTIONFS_SETUP:
2033                 rem_type1 = type;
2034                 /* Discard all similar events */
2035                 break;
2036
2037         case FUNCTIONFS_BIND:
2038         case FUNCTIONFS_UNBIND:
2039         case FUNCTIONFS_DISABLE:
2040         case FUNCTIONFS_ENABLE:
2041                 /* Discard everything other then power management. */
2042                 rem_type1 = FUNCTIONFS_SUSPEND;
2043                 rem_type2 = FUNCTIONFS_RESUME;
2044                 neg = 1;
2045                 break;
2046
2047         default:
2048                 BUG();
2049         }
2050
2051         {
2052                 u8 *ev  = ffs->ev.types, *out = ev;
2053                 unsigned n = ffs->ev.count;
2054                 for (; n; --n, ++ev)
2055                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2056                                 *out++ = *ev;
2057                         else
2058                                 pr_vdebug("purging event %d\n", *ev);
2059                 ffs->ev.count = out - ffs->ev.types;
2060         }
2061
2062         pr_vdebug("adding event %d\n", type);
2063         ffs->ev.types[ffs->ev.count++] = type;
2064         wake_up_locked(&ffs->ev.waitq);
2065 }
2066
2067 static void ffs_event_add(struct ffs_data *ffs,
2068                           enum usb_functionfs_event_type type)
2069 {
2070         unsigned long flags;
2071         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2072         __ffs_event_add(ffs, type);
2073         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2074 }
2075
2076
2077 /* Bind/unbind USB function hooks *******************************************/
2078
2079 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2080                                     struct usb_descriptor_header *desc,
2081                                     void *priv)
2082 {
2083         struct usb_endpoint_descriptor *ds = (void *)desc;
2084         struct ffs_function *func = priv;
2085         struct ffs_ep *ffs_ep;
2086
2087         /*
2088          * If hs_descriptors is not NULL then we are reading hs
2089          * descriptors now
2090          */
2091         const int isHS = func->function.hs_descriptors != NULL;
2092         unsigned idx;
2093
2094         if (type != FFS_DESCRIPTOR)
2095                 return 0;
2096
2097         if (isHS)
2098                 func->function.hs_descriptors[(long)valuep] = desc;
2099         else
2100                 func->function.fs_descriptors[(long)valuep]    = desc;
2101
2102         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2103                 return 0;
2104
2105         idx = (ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK) - 1;
2106         ffs_ep = func->eps + idx;
2107
2108         if (unlikely(ffs_ep->descs[isHS])) {
2109                 pr_vdebug("two %sspeed descriptors for EP %d\n",
2110                           isHS ? "high" : "full",
2111                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2112                 return -EINVAL;
2113         }
2114         ffs_ep->descs[isHS] = ds;
2115
2116         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2117         if (ffs_ep->ep) {
2118                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2119                 if (!ds->wMaxPacketSize)
2120                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2121         } else {
2122                 struct usb_request *req;
2123                 struct usb_ep *ep;
2124
2125                 pr_vdebug("autoconfig\n");
2126                 ep = usb_ep_autoconfig(func->gadget, ds);
2127                 if (unlikely(!ep))
2128                         return -ENOTSUPP;
2129                 ep->driver_data = func->eps + idx;
2130
2131                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2132                 if (unlikely(!req))
2133                         return -ENOMEM;
2134
2135                 ffs_ep->ep  = ep;
2136                 ffs_ep->req = req;
2137                 func->eps_revmap[ds->bEndpointAddress &
2138                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2139         }
2140         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2141
2142         return 0;
2143 }
2144
2145 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2146                                    struct usb_descriptor_header *desc,
2147                                    void *priv)
2148 {
2149         struct ffs_function *func = priv;
2150         unsigned idx;
2151         u8 newValue;
2152
2153         switch (type) {
2154         default:
2155         case FFS_DESCRIPTOR:
2156                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2157                 return 0;
2158
2159         case FFS_INTERFACE:
2160                 idx = *valuep;
2161                 if (func->interfaces_nums[idx] < 0) {
2162                         int id = usb_interface_id(func->conf, &func->function);
2163                         if (unlikely(id < 0))
2164                                 return id;
2165                         func->interfaces_nums[idx] = id;
2166                 }
2167                 newValue = func->interfaces_nums[idx];
2168                 break;
2169
2170         case FFS_STRING:
2171                 /* String' IDs are allocated when fsf_data is bound to cdev */
2172                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2173                 break;
2174
2175         case FFS_ENDPOINT:
2176                 /*
2177                  * USB_DT_ENDPOINT are handled in
2178                  * __ffs_func_bind_do_descs().
2179                  */
2180                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2181                         return 0;
2182
2183                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2184                 if (unlikely(!func->eps[idx].ep))
2185                         return -EINVAL;
2186
2187                 {
2188                         struct usb_endpoint_descriptor **descs;
2189                         descs = func->eps[idx].descs;
2190                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2191                 }
2192                 break;
2193         }
2194
2195         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2196         *valuep = newValue;
2197         return 0;
2198 }
2199
2200 static int ffs_func_bind(struct usb_configuration *c,
2201                          struct usb_function *f)
2202 {
2203         struct ffs_function *func = ffs_func_from_usb(f);
2204         struct ffs_data *ffs = func->ffs;
2205
2206         const int full = !!func->ffs->fs_descs_count;
2207         const int high = gadget_is_dualspeed(func->gadget) &&
2208                 func->ffs->hs_descs_count;
2209
2210         int ret;
2211
2212         /* Make it a single chunk, less management later on */
2213         struct {
2214                 struct ffs_ep eps[ffs->eps_count];
2215                 struct usb_descriptor_header
2216                         *fs_descs[full ? ffs->fs_descs_count + 1 : 0];
2217                 struct usb_descriptor_header
2218                         *hs_descs[high ? ffs->hs_descs_count + 1 : 0];
2219                 short inums[ffs->interfaces_count];
2220                 char raw_descs[high ? ffs->raw_descs_length
2221                                     : ffs->raw_fs_descs_length];
2222         } *data;
2223
2224         ENTER();
2225
2226         /* Only high speed but not supported by gadget? */
2227         if (unlikely(!(full | high)))
2228                 return -ENOTSUPP;
2229
2230         /* Allocate */
2231         data = kmalloc(sizeof *data, GFP_KERNEL);
2232         if (unlikely(!data))
2233                 return -ENOMEM;
2234
2235         /* Zero */
2236         memset(data->eps, 0, sizeof data->eps);
2237         memcpy(data->raw_descs, ffs->raw_descs + 16, sizeof data->raw_descs);
2238         memset(data->inums, 0xff, sizeof data->inums);
2239         for (ret = ffs->eps_count; ret; --ret)
2240                 data->eps[ret].num = -1;
2241
2242         /* Save pointers */
2243         func->eps             = data->eps;
2244         func->interfaces_nums = data->inums;
2245
2246         /*
2247          * Go through all the endpoint descriptors and allocate
2248          * endpoints first, so that later we can rewrite the endpoint
2249          * numbers without worrying that it may be described later on.
2250          */
2251         if (likely(full)) {
2252                 func->function.fs_descriptors = data->fs_descs;
2253                 ret = ffs_do_descs(ffs->fs_descs_count,
2254                                    data->raw_descs,
2255                                    sizeof data->raw_descs,
2256                                    __ffs_func_bind_do_descs, func);
2257                 if (unlikely(ret < 0))
2258                         goto error;
2259         } else {
2260                 ret = 0;
2261         }
2262
2263         if (likely(high)) {
2264                 func->function.hs_descriptors = data->hs_descs;
2265                 ret = ffs_do_descs(ffs->hs_descs_count,
2266                                    data->raw_descs + ret,
2267                                    (sizeof data->raw_descs) - ret,
2268                                    __ffs_func_bind_do_descs, func);
2269         }
2270
2271         /*
2272          * Now handle interface numbers allocation and interface and
2273          * endpoint numbers rewriting.  We can do that in one go
2274          * now.
2275          */
2276         ret = ffs_do_descs(ffs->fs_descs_count +
2277                            (high ? ffs->hs_descs_count : 0),
2278                            data->raw_descs, sizeof data->raw_descs,
2279                            __ffs_func_bind_do_nums, func);
2280         if (unlikely(ret < 0))
2281                 goto error;
2282
2283         /* And we're done */
2284         ffs_event_add(ffs, FUNCTIONFS_BIND);
2285         return 0;
2286
2287 error:
2288         /* XXX Do we need to release all claimed endpoints here? */
2289         return ret;
2290 }
2291
2292
2293 /* Other USB function hooks *************************************************/
2294
2295 static void ffs_func_unbind(struct usb_configuration *c,
2296                             struct usb_function *f)
2297 {
2298         struct ffs_function *func = ffs_func_from_usb(f);
2299         struct ffs_data *ffs = func->ffs;
2300
2301         ENTER();
2302
2303         if (ffs->func == func) {
2304                 ffs_func_eps_disable(func);
2305                 ffs->func = NULL;
2306         }
2307
2308         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
2309
2310         ffs_func_free(func);
2311 }
2312
2313 static int ffs_func_set_alt(struct usb_function *f,
2314                             unsigned interface, unsigned alt)
2315 {
2316         struct ffs_function *func = ffs_func_from_usb(f);
2317         struct ffs_data *ffs = func->ffs;
2318         int ret = 0, intf;
2319
2320         if (alt != (unsigned)-1) {
2321                 intf = ffs_func_revmap_intf(func, interface);
2322                 if (unlikely(intf < 0))
2323                         return intf;
2324         }
2325
2326         if (ffs->func)
2327                 ffs_func_eps_disable(ffs->func);
2328
2329         if (ffs->state != FFS_ACTIVE)
2330                 return -ENODEV;
2331
2332         if (alt == (unsigned)-1) {
2333                 ffs->func = NULL;
2334                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2335                 return 0;
2336         }
2337
2338         ffs->func = func;
2339         ret = ffs_func_eps_enable(func);
2340         if (likely(ret >= 0))
2341                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2342         return ret;
2343 }
2344
2345 static void ffs_func_disable(struct usb_function *f)
2346 {
2347         ffs_func_set_alt(f, 0, (unsigned)-1);
2348 }
2349
2350 static int ffs_func_setup(struct usb_function *f,
2351                           const struct usb_ctrlrequest *creq)
2352 {
2353         struct ffs_function *func = ffs_func_from_usb(f);
2354         struct ffs_data *ffs = func->ffs;
2355         unsigned long flags;
2356         int ret;
2357
2358         ENTER();
2359
2360         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2361         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2362         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2363         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
2364         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
2365
2366         /*
2367          * Most requests directed to interface go through here
2368          * (notable exceptions are set/get interface) so we need to
2369          * handle them.  All other either handled by composite or
2370          * passed to usb_configuration->setup() (if one is set).  No
2371          * matter, we will handle requests directed to endpoint here
2372          * as well (as it's straightforward) but what to do with any
2373          * other request?
2374          */
2375         if (ffs->state != FFS_ACTIVE)
2376                 return -ENODEV;
2377
2378         switch (creq->bRequestType & USB_RECIP_MASK) {
2379         case USB_RECIP_INTERFACE:
2380                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
2381                 if (unlikely(ret < 0))
2382                         return ret;
2383                 break;
2384
2385         case USB_RECIP_ENDPOINT:
2386                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
2387                 if (unlikely(ret < 0))
2388                         return ret;
2389                 break;
2390
2391         default:
2392                 return -EOPNOTSUPP;
2393         }
2394
2395         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2396         ffs->ev.setup = *creq;
2397         ffs->ev.setup.wIndex = cpu_to_le16(ret);
2398         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
2399         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2400
2401         return 0;
2402 }
2403
2404 static void ffs_func_suspend(struct usb_function *f)
2405 {
2406         ENTER();
2407         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
2408 }
2409
2410 static void ffs_func_resume(struct usb_function *f)
2411 {
2412         ENTER();
2413         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
2414 }
2415
2416
2417 /* Endpoint and interface numbers reverse mapping ***************************/
2418
2419 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
2420 {
2421         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
2422         return num ? num : -EDOM;
2423 }
2424
2425 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
2426 {
2427         short *nums = func->interfaces_nums;
2428         unsigned count = func->ffs->interfaces_count;
2429
2430         for (; count; --count, ++nums) {
2431                 if (*nums >= 0 && *nums == intf)
2432                         return nums - func->interfaces_nums;
2433         }
2434
2435         return -EDOM;
2436 }
2437
2438
2439 /* Misc helper functions ****************************************************/
2440
2441 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
2442 {
2443         return nonblock
2444                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
2445                 : mutex_lock_interruptible(mutex);
2446 }
2447
2448 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
2449 {
2450         char *data;
2451
2452         if (unlikely(!len))
2453                 return NULL;
2454
2455         data = kmalloc(len, GFP_KERNEL);
2456         if (unlikely(!data))
2457                 return ERR_PTR(-ENOMEM);
2458
2459         if (unlikely(__copy_from_user(data, buf, len))) {
2460                 kfree(data);
2461                 return ERR_PTR(-EFAULT);
2462         }
2463
2464         pr_vdebug("Buffer from user space:\n");
2465         ffs_dump_mem("", data, len);
2466
2467         return data;
2468 }