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         reinit_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         /* Are we still active? */
 762         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
 763                 ret = -ENODEV;
 764                 goto error;
 765         }
 766
 767         /* Wait for endpoint to be enabled */
 768         ep = epfile->ep;
 769         if (!ep) {
 770                 if (file->f_flags & O_NONBLOCK) {
 771                         ret = -EAGAIN;
 772                         goto error;
 773                 }
 774
 775                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
 776                 if (ret) {
 777                         ret = -EINTR;
 778                         goto error;
 779                 }
 780         }
 781
 782         /* Do we halt? */
 783         halt = !read == !epfile->in;
 784         if (halt && epfile->isoc) {
 785                 ret = -EINVAL;
 786                 goto error;
 787         }
 788
 789         /* Allocate & copy */
 790         if (!halt) {
 791                 data = kmalloc(len, GFP_KERNEL);
 792                 if (unlikely(!data))
 793                         return -ENOMEM;
 794
 795                 if (!read && unlikely(copy_from_user(data, buf, len))) {
 796                         ret = -EFAULT;
 797                         goto error;
 798                 }
 799         }
 800
 801         /* We will be using request */
 802         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 803         if (unlikely(ret))
 804                 goto error;
 805
 806         spin_lock_irq(&epfile->ffs->eps_lock);
 807
 808         if (epfile->ep != ep) {
 809                 /* In the meantime, endpoint got disabled or changed. */
 810                 ret = -ESHUTDOWN;
 811                 spin_unlock_irq(&epfile->ffs->eps_lock);
 812         } else if (halt) {
 813                 /* Halt */
 814                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 815                         usb_ep_set_halt(ep->ep);
 816                 spin_unlock_irq(&epfile->ffs->eps_lock);
 817                 ret = -EBADMSG;
 818         } else {
 819                 /* Fire the request */
 820                 DECLARE_COMPLETION_ONSTACK(done);
 821
 822                 struct usb_request *req = ep->req;
 823                 req->context  = &done;
 824                 req->complete = ffs_epfile_io_complete;
 825                 req->buf      = data;
 826                 req->length   = len;
 827
 828                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 829
 830                 spin_unlock_irq(&epfile->ffs->eps_lock);
 831
 832                 if (unlikely(ret < 0)) {
 833                         /* nop */
 834                 } else if (unlikely(wait_for_completion_interruptible(&done))) {
 835                         ret = -EINTR;
 836                         usb_ep_dequeue(ep->ep, req);
 837                 } else {
 838                         ret = ep->status;
 839                         if (read && ret > 0 &&
 840                             unlikely(copy_to_user(buf, data, ret)))
 841                                 ret = -EFAULT;
 842                 }
 843         }
 844
 845         mutex_unlock(&epfile->mutex);
 846 error:
 847         kfree(data);
 848         return ret;
 849 }
 850
 851 static ssize_t
 852 ffs_epfile_write(struct file *file, const char __user *buf, size_t len,
 853                  loff_t *ptr)
 854 {
 855         ENTER();
 856
 857         return ffs_epfile_io(file, (char __user *)buf, len, 0);
 858 }
 859
 860 static ssize_t
 861 ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr)
 862 {
 863         ENTER();
 864
 865         return ffs_epfile_io(file, buf, len, 1);
 866 }
 867
 868 static int
 869 ffs_epfile_open(struct inode *inode, struct file *file)
 870 {
 871         struct ffs_epfile *epfile = inode->i_private;
 872
 873         ENTER();
 874
 875         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 876                 return -ENODEV;
 877
 878         file->private_data = epfile;
 879         ffs_data_opened(epfile->ffs);
 880
 881         return 0;
 882 }
 883
 884 static int
 885 ffs_epfile_release(struct inode *inode, struct file *file)
 886 {
 887         struct ffs_epfile *epfile = inode->i_private;
 888
 889         ENTER();
 890
 891         ffs_data_closed(epfile->ffs);
 892
 893         return 0;
 894 }
 895
 896 static long ffs_epfile_ioctl(struct file *file, unsigned code,
 897                              unsigned long value)
 898 {
 899         struct ffs_epfile *epfile = file->private_data;
 900         int ret;
 901
 902         ENTER();
 903
 904         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 905                 return -ENODEV;
 906
 907         spin_lock_irq(&epfile->ffs->eps_lock);
 908         if (likely(epfile->ep)) {
 909                 switch (code) {
 910                 case FUNCTIONFS_FIFO_STATUS:
 911                         ret = usb_ep_fifo_status(epfile->ep->ep);
 912                         break;
 913                 case FUNCTIONFS_FIFO_FLUSH:
 914                         usb_ep_fifo_flush(epfile->ep->ep);
 915                         ret = 0;
 916                         break;
 917                 case FUNCTIONFS_CLEAR_HALT:
 918                         ret = usb_ep_clear_halt(epfile->ep->ep);
 919                         break;
 920                 case FUNCTIONFS_ENDPOINT_REVMAP:
 921                         ret = epfile->ep->num;
 922                         break;
 923                 default:
 924                         ret = -ENOTTY;
 925                 }
 926         } else {
 927                 ret = -ENODEV;
 928         }
 929         spin_unlock_irq(&epfile->ffs->eps_lock);
 930
 931         return ret;
 932 }
 933
 934 static const struct file_operations ffs_epfile_operations = {
 935         .llseek =       no_llseek,
 936
 937         .open =         ffs_epfile_open,
 938         .write =        ffs_epfile_write,
 939         .read =         ffs_epfile_read,
 940         .release =      ffs_epfile_release,
 941         .unlocked_ioctl =       ffs_epfile_ioctl,
 942 };
 943
 944
 945 /* File system and super block operations ***********************************/
 946
 947 /*
 948  * Mounting the file system creates a controller file, used first for
 949  * function configuration then later for event monitoring.
 950  */
 951
 952 static struct inode *__must_check
 953 ffs_sb_make_inode(struct super_block *sb, void *data,
 954                   const struct file_operations *fops,
 955                   const struct inode_operations *iops,
 956                   struct ffs_file_perms *perms)
 957 {
 958         struct inode *inode;
 959
 960         ENTER();
 961
 962         inode = new_inode(sb);
 963
 964         if (likely(inode)) {
 965                 struct timespec current_time = CURRENT_TIME;
 966
 967                 inode->i_ino     = get_next_ino();
 968                 inode->i_mode    = perms->mode;
 969                 inode->i_uid     = perms->uid;
 970                 inode->i_gid     = perms->gid;
 971                 inode->i_atime   = current_time;
 972                 inode->i_mtime   = current_time;
 973                 inode->i_ctime   = current_time;
 974                 inode->i_private = data;
 975                 if (fops)
 976                         inode->i_fop = fops;
 977                 if (iops)
 978                         inode->i_op  = iops;
 979         }
 980
 981         return inode;
 982 }
 983
 984 /* Create "regular" file */
 985 static struct inode *ffs_sb_create_file(struct super_block *sb,
 986                                         const char *name, void *data,
 987                                         const struct file_operations *fops,
 988                                         struct dentry **dentry_p)
 989 {
 990         struct ffs_data *ffs = sb->s_fs_info;
 991         struct dentry   *dentry;
 992         struct inode    *inode;
 993
 994         ENTER();
 995
 996         dentry = d_alloc_name(sb->s_root, name);
 997         if (unlikely(!dentry))
 998                 return NULL;
 999
1000         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1001         if (unlikely(!inode)) {
1002                 dput(dentry);
1003                 return NULL;
1004         }
1005
1006         d_add(dentry, inode);
1007         if (dentry_p)
1008                 *dentry_p = dentry;
1009
1010         return inode;
1011 }
1012
1013 /* Super block */
1014 static const struct super_operations ffs_sb_operations = {
1015         .statfs =       simple_statfs,
1016         .drop_inode =   generic_delete_inode,
1017 };
1018
1019 struct ffs_sb_fill_data {
1020         struct ffs_file_perms perms;
1021         umode_t root_mode;
1022         const char *dev_name;
1023         struct ffs_data *ffs_data;
1024 };
1025
1026 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1027 {
1028         struct ffs_sb_fill_data *data = _data;
1029         struct inode    *inode;
1030         struct ffs_data *ffs = data->ffs_data;
1031
1032         ENTER();
1033
1034         ffs->sb              = sb;
1035         data->ffs_data       = NULL;
1036         sb->s_fs_info        = ffs;
1037         sb->s_blocksize      = PAGE_CACHE_SIZE;
1038         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1039         sb->s_magic          = FUNCTIONFS_MAGIC;
1040         sb->s_op             = &ffs_sb_operations;
1041         sb->s_time_gran      = 1;
1042
1043         /* Root inode */
1044         data->perms.mode = data->root_mode;
1045         inode = ffs_sb_make_inode(sb, NULL,
1046                                   &simple_dir_operations,
1047                                   &simple_dir_inode_operations,
1048                                   &data->perms);
1049         sb->s_root = d_make_root(inode);
1050         if (unlikely(!sb->s_root))
1051                 return -ENOMEM;
1052
1053         /* EP0 file */
1054         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1055                                          &ffs_ep0_operations, NULL)))
1056                 return -ENOMEM;
1057
1058         return 0;
1059 }
1060
1061 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1062 {
1063         ENTER();
1064
1065         if (!opts || !*opts)
1066                 return 0;
1067
1068         for (;;) {
1069                 unsigned long value;
1070                 char *eq, *comma;
1071
1072                 /* Option limit */
1073                 comma = strchr(opts, ',');
1074                 if (comma)
1075                         *comma = 0;
1076
1077                 /* Value limit */
1078                 eq = strchr(opts, '=');
1079                 if (unlikely(!eq)) {
1080                         pr_err("'=' missing in %s\n", opts);
1081                         return -EINVAL;
1082                 }
1083                 *eq = 0;
1084
1085                 /* Parse value */
1086                 if (kstrtoul(eq + 1, 0, &value)) {
1087                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1088                         return -EINVAL;
1089                 }
1090
1091                 /* Interpret option */
1092                 switch (eq - opts) {
1093                 case 5:
1094                         if (!memcmp(opts, "rmode", 5))
1095                                 data->root_mode  = (value & 0555) | S_IFDIR;
1096                         else if (!memcmp(opts, "fmode", 5))
1097                                 data->perms.mode = (value & 0666) | S_IFREG;
1098                         else
1099                                 goto invalid;
1100                         break;
1101
1102                 case 4:
1103                         if (!memcmp(opts, "mode", 4)) {
1104                                 data->root_mode  = (value & 0555) | S_IFDIR;
1105                                 data->perms.mode = (value & 0666) | S_IFREG;
1106                         } else {
1107                                 goto invalid;
1108                         }
1109                         break;
1110
1111                 case 3:
1112                         if (!memcmp(opts, "uid", 3)) {
1113                                 data->perms.uid = make_kuid(current_user_ns(), value);
1114                                 if (!uid_valid(data->perms.uid)) {
1115                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1116                                         return -EINVAL;
1117                                 }
1118                         } else if (!memcmp(opts, "gid", 3)) {
1119                                 data->perms.gid = make_kgid(current_user_ns(), value);
1120                                 if (!gid_valid(data->perms.gid)) {
1121                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1122                                         return -EINVAL;
1123                                 }
1124                         } else {
1125                                 goto invalid;
1126                         }
1127                         break;
1128
1129                 default:
1130 invalid:
1131                         pr_err("%s: invalid option\n", opts);
1132                         return -EINVAL;
1133                 }
1134
1135                 /* Next iteration */
1136                 if (!comma)
1137                         break;
1138                 opts = comma + 1;
1139         }
1140
1141         return 0;
1142 }
1143
1144 /* "mount -t functionfs dev_name /dev/function" ends up here */
1145
1146 static struct dentry *
1147 ffs_fs_mount(struct file_system_type *t, int flags,
1148               const char *dev_name, void *opts)
1149 {
1150         struct ffs_sb_fill_data data = {
1151                 .perms = {
1152                         .mode = S_IFREG | 0600,
1153                         .uid = GLOBAL_ROOT_UID,
1154                         .gid = GLOBAL_ROOT_GID,
1155                 },
1156                 .root_mode = S_IFDIR | 0500,
1157         };
1158         struct dentry *rv;
1159         int ret;
1160         void *ffs_dev;
1161         struct ffs_data *ffs;
1162
1163         ENTER();
1164
1165         ret = ffs_fs_parse_opts(&data, opts);
1166         if (unlikely(ret < 0))
1167                 return ERR_PTR(ret);
1168
1169         ffs = ffs_data_new();
1170         if (unlikely(!ffs))
1171                 return ERR_PTR(-ENOMEM);
1172         ffs->file_perms = data.perms;
1173
1174         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1175         if (unlikely(!ffs->dev_name)) {
1176                 ffs_data_put(ffs);
1177                 return ERR_PTR(-ENOMEM);
1178         }
1179
1180         ffs_dev = functionfs_acquire_dev_callback(dev_name);
1181         if (IS_ERR(ffs_dev)) {
1182                 ffs_data_put(ffs);
1183                 return ERR_CAST(ffs_dev);
1184         }
1185         ffs->private_data = ffs_dev;
1186         data.ffs_data = ffs;
1187
1188         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1189         if (IS_ERR(rv) && data.ffs_data) {
1190                 functionfs_release_dev_callback(data.ffs_data);
1191                 ffs_data_put(data.ffs_data);
1192         }
1193         return rv;
1194 }
1195
1196 static void
1197 ffs_fs_kill_sb(struct super_block *sb)
1198 {
1199         ENTER();
1200
1201         kill_litter_super(sb);
1202         if (sb->s_fs_info) {
1203                 functionfs_release_dev_callback(sb->s_fs_info);
1204                 ffs_data_put(sb->s_fs_info);
1205         }
1206 }
1207
1208 static struct file_system_type ffs_fs_type = {
1209         .owner          = THIS_MODULE,
1210         .name           = "functionfs",
1211         .mount          = ffs_fs_mount,
1212         .kill_sb        = ffs_fs_kill_sb,
1213 };
1214 MODULE_ALIAS_FS("functionfs");
1215
1216
1217 /* Driver's main init/cleanup functions *************************************/
1218
1219 static int functionfs_init(void)
1220 {
1221         int ret;
1222
1223         ENTER();
1224
1225         ret = register_filesystem(&ffs_fs_type);
1226         if (likely(!ret))
1227                 pr_info("file system registered\n");
1228         else
1229                 pr_err("failed registering file system (%d)\n", ret);
1230
1231         return ret;
1232 }
1233
1234 static void functionfs_cleanup(void)
1235 {
1236         ENTER();
1237
1238         pr_info("unloading\n");
1239         unregister_filesystem(&ffs_fs_type);
1240 }
1241
1242
1243 /* ffs_data and ffs_function construction and destruction code **************/
1244
1245 static void ffs_data_clear(struct ffs_data *ffs);
1246 static void ffs_data_reset(struct ffs_data *ffs);
1247
1248 static void ffs_data_get(struct ffs_data *ffs)
1249 {
1250         ENTER();
1251
1252         atomic_inc(&ffs->ref);
1253 }
1254
1255 static void ffs_data_opened(struct ffs_data *ffs)
1256 {
1257         ENTER();
1258
1259         atomic_inc(&ffs->ref);
1260         atomic_inc(&ffs->opened);
1261 }
1262
1263 static void ffs_data_put(struct ffs_data *ffs)
1264 {
1265         ENTER();
1266
1267         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1268                 pr_info("%s(): freeing\n", __func__);
1269                 ffs_data_clear(ffs);
1270                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1271                        waitqueue_active(&ffs->ep0req_completion.wait));
1272                 kfree(ffs->dev_name);
1273                 kfree(ffs);
1274         }
1275 }
1276
1277 static void ffs_data_closed(struct ffs_data *ffs)
1278 {
1279         ENTER();
1280
1281         if (atomic_dec_and_test(&ffs->opened)) {
1282                 ffs->state = FFS_CLOSING;
1283                 ffs_data_reset(ffs);
1284         }
1285
1286         ffs_data_put(ffs);
1287 }
1288
1289 static struct ffs_data *ffs_data_new(void)
1290 {
1291         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1292         if (unlikely(!ffs))
1293                 return 0;
1294
1295         ENTER();
1296
1297         atomic_set(&ffs->ref, 1);
1298         atomic_set(&ffs->opened, 0);
1299         ffs->state = FFS_READ_DESCRIPTORS;
1300         mutex_init(&ffs->mutex);
1301         spin_lock_init(&ffs->eps_lock);
1302         init_waitqueue_head(&ffs->ev.waitq);
1303         init_completion(&ffs->ep0req_completion);
1304
1305         /* XXX REVISIT need to update it in some places, or do we? */
1306         ffs->ev.can_stall = 1;
1307
1308         return ffs;
1309 }
1310
1311 static void ffs_data_clear(struct ffs_data *ffs)
1312 {
1313         ENTER();
1314
1315         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags))
1316                 functionfs_closed_callback(ffs);
1317
1318         BUG_ON(ffs->gadget);
1319
1320         if (ffs->epfiles)
1321                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1322
1323         kfree(ffs->raw_descs);
1324         kfree(ffs->raw_strings);
1325         kfree(ffs->stringtabs);
1326 }
1327
1328 static void ffs_data_reset(struct ffs_data *ffs)
1329 {
1330         ENTER();
1331
1332         ffs_data_clear(ffs);
1333
1334         ffs->epfiles = NULL;
1335         ffs->raw_descs = NULL;
1336         ffs->raw_strings = NULL;
1337         ffs->stringtabs = NULL;
1338
1339         ffs->raw_descs_length = 0;
1340         ffs->raw_fs_descs_length = 0;
1341         ffs->fs_descs_count = 0;
1342         ffs->hs_descs_count = 0;
1343
1344         ffs->strings_count = 0;
1345         ffs->interfaces_count = 0;
1346         ffs->eps_count = 0;
1347
1348         ffs->ev.count = 0;
1349
1350         ffs->state = FFS_READ_DESCRIPTORS;
1351         ffs->setup_state = FFS_NO_SETUP;
1352         ffs->flags = 0;
1353 }
1354
1355
1356 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1357 {
1358         struct usb_gadget_strings **lang;
1359         int first_id;
1360
1361         ENTER();
1362
1363         if (WARN_ON(ffs->state != FFS_ACTIVE
1364                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1365                 return -EBADFD;
1366
1367         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1368         if (unlikely(first_id < 0))
1369                 return first_id;
1370
1371         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1372         if (unlikely(!ffs->ep0req))
1373                 return -ENOMEM;
1374         ffs->ep0req->complete = ffs_ep0_complete;
1375         ffs->ep0req->context = ffs;
1376
1377         lang = ffs->stringtabs;
1378         for (lang = ffs->stringtabs; *lang; ++lang) {
1379                 struct usb_string *str = (*lang)->strings;
1380                 int id = first_id;
1381                 for (; str->s; ++id, ++str)
1382                         str->id = id;
1383         }
1384
1385         ffs->gadget = cdev->gadget;
1386         ffs_data_get(ffs);
1387         return 0;
1388 }
1389
1390 static void functionfs_unbind(struct ffs_data *ffs)
1391 {
1392         ENTER();
1393
1394         if (!WARN_ON(!ffs->gadget)) {
1395                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1396                 ffs->ep0req = NULL;
1397                 ffs->gadget = NULL;
1398                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1399                 ffs_data_put(ffs);
1400         }
1401 }
1402
1403 static int ffs_epfiles_create(struct ffs_data *ffs)
1404 {
1405         struct ffs_epfile *epfile, *epfiles;
1406         unsigned i, count;
1407
1408         ENTER();
1409
1410         count = ffs->eps_count;
1411         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1412         if (!epfiles)
1413                 return -ENOMEM;
1414
1415         epfile = epfiles;
1416         for (i = 1; i <= count; ++i, ++epfile) {
1417                 epfile->ffs = ffs;
1418                 mutex_init(&epfile->mutex);
1419                 init_waitqueue_head(&epfile->wait);
1420                 sprintf(epfiles->name, "ep%u",  i);
1421                 if (!unlikely(ffs_sb_create_file(ffs->sb, epfiles->name, epfile,
1422                                                  &ffs_epfile_operations,
1423                                                  &epfile->dentry))) {
1424                         ffs_epfiles_destroy(epfiles, i - 1);
1425                         return -ENOMEM;
1426                 }
1427         }
1428
1429         ffs->epfiles = epfiles;
1430         return 0;
1431 }
1432
1433 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1434 {
1435         struct ffs_epfile *epfile = epfiles;
1436
1437         ENTER();
1438
1439         for (; count; --count, ++epfile) {
1440                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1441                        waitqueue_active(&epfile->wait));
1442                 if (epfile->dentry) {
1443                         d_delete(epfile->dentry);
1444                         dput(epfile->dentry);
1445                         epfile->dentry = NULL;
1446                 }
1447         }
1448
1449         kfree(epfiles);
1450 }
1451
1452 static int functionfs_bind_config(struct usb_composite_dev *cdev,
1453                                   struct usb_configuration *c,
1454                                   struct ffs_data *ffs)
1455 {
1456         struct ffs_function *func;
1457         int ret;
1458
1459         ENTER();
1460
1461         func = kzalloc(sizeof *func, GFP_KERNEL);
1462         if (unlikely(!func))
1463                 return -ENOMEM;
1464
1465         func->function.name    = "Function FS Gadget";
1466         func->function.strings = ffs->stringtabs;
1467
1468         func->function.bind    = ffs_func_bind;
1469         func->function.unbind  = ffs_func_unbind;
1470         func->function.set_alt = ffs_func_set_alt;
1471         func->function.disable = ffs_func_disable;
1472         func->function.setup   = ffs_func_setup;
1473         func->function.suspend = ffs_func_suspend;
1474         func->function.resume  = ffs_func_resume;
1475
1476         func->conf   = c;
1477         func->gadget = cdev->gadget;
1478         func->ffs = ffs;
1479         ffs_data_get(ffs);
1480
1481         ret = usb_add_function(c, &func->function);
1482         if (unlikely(ret))
1483                 ffs_func_free(func);
1484
1485         return ret;
1486 }
1487
1488 static void ffs_func_free(struct ffs_function *func)
1489 {
1490         struct ffs_ep *ep         = func->eps;
1491         unsigned count            = func->ffs->eps_count;
1492         unsigned long flags;
1493
1494         ENTER();
1495
1496         /* cleanup after autoconfig */
1497         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1498         do {
1499                 if (ep->ep && ep->req)
1500                         usb_ep_free_request(ep->ep, ep->req);
1501                 ep->req = NULL;
1502                 ++ep;
1503         } while (--count);
1504         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1505
1506         ffs_data_put(func->ffs);
1507
1508         kfree(func->eps);
1509         /*
1510          * eps and interfaces_nums are allocated in the same chunk so
1511          * only one free is required.  Descriptors are also allocated
1512          * in the same chunk.
1513          */
1514
1515         kfree(func);
1516 }
1517
1518 static void ffs_func_eps_disable(struct ffs_function *func)
1519 {
1520         struct ffs_ep *ep         = func->eps;
1521         struct ffs_epfile *epfile = func->ffs->epfiles;
1522         unsigned count            = func->ffs->eps_count;
1523         unsigned long flags;
1524
1525         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1526         do {
1527                 /* pending requests get nuked */
1528                 if (likely(ep->ep))
1529                         usb_ep_disable(ep->ep);
1530                 epfile->ep = NULL;
1531
1532                 ++ep;
1533                 ++epfile;
1534         } while (--count);
1535         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1536 }
1537
1538 static int ffs_func_eps_enable(struct ffs_function *func)
1539 {
1540         struct ffs_data *ffs      = func->ffs;
1541         struct ffs_ep *ep         = func->eps;
1542         struct ffs_epfile *epfile = ffs->epfiles;
1543         unsigned count            = ffs->eps_count;
1544         unsigned long flags;
1545         int ret = 0;
1546
1547         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1548         do {
1549                 struct usb_endpoint_descriptor *ds;
1550                 ds = ep->descs[ep->descs[1] ? 1 : 0];
1551
1552                 ep->ep->driver_data = ep;
1553                 ep->ep->desc = ds;
1554                 ret = usb_ep_enable(ep->ep);
1555                 if (likely(!ret)) {
1556                         epfile->ep = ep;
1557                         epfile->in = usb_endpoint_dir_in(ds);
1558                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1559                 } else {
1560                         break;
1561                 }
1562
1563                 wake_up(&epfile->wait);
1564
1565                 ++ep;
1566                 ++epfile;
1567         } while (--count);
1568         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1569
1570         return ret;
1571 }
1572
1573
1574 /* Parsing and building descriptors and strings *****************************/
1575
1576 /*
1577  * This validates if data pointed by data is a valid USB descriptor as
1578  * well as record how many interfaces, endpoints and strings are
1579  * required by given configuration.  Returns address after the
1580  * descriptor or NULL if data is invalid.
1581  */
1582
1583 enum ffs_entity_type {
1584         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1585 };
1586
1587 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1588                                    u8 *valuep,
1589                                    struct usb_descriptor_header *desc,
1590                                    void *priv);
1591
1592 static int __must_check ffs_do_desc(char *data, unsigned len,
1593                                     ffs_entity_callback entity, void *priv)
1594 {
1595         struct usb_descriptor_header *_ds = (void *)data;
1596         u8 length;
1597         int ret;
1598
1599         ENTER();
1600
1601         /* At least two bytes are required: length and type */
1602         if (len < 2) {
1603                 pr_vdebug("descriptor too short\n");
1604                 return -EINVAL;
1605         }
1606
1607         /* If we have at least as many bytes as the descriptor takes? */
1608         length = _ds->bLength;
1609         if (len < length) {
1610                 pr_vdebug("descriptor longer then available data\n");
1611                 return -EINVAL;
1612         }
1613
1614 #define __entity_check_INTERFACE(val)  1
1615 #define __entity_check_STRING(val)     (val)
1616 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1617 #define __entity(type, val) do {                                        \
1618                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1619                 if (unlikely(!__entity_check_ ##type(val))) {           \
1620                         pr_vdebug("invalid entity's value\n");          \
1621                         return -EINVAL;                                 \
1622                 }                                                       \
1623                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1624                 if (unlikely(ret < 0)) {                                \
1625                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1626                                  (val), ret);                           \
1627                         return ret;                                     \
1628                 }                                                       \
1629         } while (0)
1630
1631         /* Parse descriptor depending on type. */
1632         switch (_ds->bDescriptorType) {
1633         case USB_DT_DEVICE:
1634         case USB_DT_CONFIG:
1635         case USB_DT_STRING:
1636         case USB_DT_DEVICE_QUALIFIER:
1637                 /* function can't have any of those */
1638                 pr_vdebug("descriptor reserved for gadget: %d\n",
1639                       _ds->bDescriptorType);
1640                 return -EINVAL;
1641
1642         case USB_DT_INTERFACE: {
1643                 struct usb_interface_descriptor *ds = (void *)_ds;
1644                 pr_vdebug("interface descriptor\n");
1645                 if (length != sizeof *ds)
1646                         goto inv_length;
1647
1648                 __entity(INTERFACE, ds->bInterfaceNumber);
1649                 if (ds->iInterface)
1650                         __entity(STRING, ds->iInterface);
1651         }
1652                 break;
1653
1654         case USB_DT_ENDPOINT: {
1655                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1656                 pr_vdebug("endpoint descriptor\n");
1657                 if (length != USB_DT_ENDPOINT_SIZE &&
1658                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1659                         goto inv_length;
1660                 __entity(ENDPOINT, ds->bEndpointAddress);
1661         }
1662                 break;
1663
1664         case HID_DT_HID:
1665                 pr_vdebug("hid descriptor\n");
1666                 if (length != sizeof(struct hid_descriptor))
1667                         goto inv_length;
1668                 break;
1669
1670         case USB_DT_OTG:
1671                 if (length != sizeof(struct usb_otg_descriptor))
1672                         goto inv_length;
1673                 break;
1674
1675         case USB_DT_INTERFACE_ASSOCIATION: {
1676                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1677                 pr_vdebug("interface association descriptor\n");
1678                 if (length != sizeof *ds)
1679                         goto inv_length;
1680                 if (ds->iFunction)
1681                         __entity(STRING, ds->iFunction);
1682         }
1683                 break;
1684
1685         case USB_DT_OTHER_SPEED_CONFIG:
1686         case USB_DT_INTERFACE_POWER:
1687         case USB_DT_DEBUG:
1688         case USB_DT_SECURITY:
1689         case USB_DT_CS_RADIO_CONTROL:
1690                 /* TODO */
1691                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1692                 return -EINVAL;
1693
1694         default:
1695                 /* We should never be here */
1696                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1697                 return -EINVAL;
1698
1699 inv_length:
1700                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1701                           _ds->bLength, _ds->bDescriptorType);
1702                 return -EINVAL;
1703         }
1704
1705 #undef __entity
1706 #undef __entity_check_DESCRIPTOR
1707 #undef __entity_check_INTERFACE
1708 #undef __entity_check_STRING
1709 #undef __entity_check_ENDPOINT
1710
1711         return length;
1712 }
1713
1714 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1715                                      ffs_entity_callback entity, void *priv)
1716 {
1717         const unsigned _len = len;
1718         unsigned long num = 0;
1719
1720         ENTER();
1721
1722         for (;;) {
1723                 int ret;
1724
1725                 if (num == count)
1726                         data = NULL;
1727
1728                 /* Record "descriptor" entity */
1729                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1730                 if (unlikely(ret < 0)) {
1731                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1732                                  num, ret);
1733                         return ret;
1734                 }
1735
1736                 if (!data)
1737                         return _len - len;
1738
1739                 ret = ffs_do_desc(data, len, entity, priv);
1740                 if (unlikely(ret < 0)) {
1741                         pr_debug("%s returns %d\n", __func__, ret);
1742                         return ret;
1743                 }
1744
1745                 len -= ret;
1746                 data += ret;
1747                 ++num;
1748         }
1749 }
1750
1751 static int __ffs_data_do_entity(enum ffs_entity_type type,
1752                                 u8 *valuep, struct usb_descriptor_header *desc,
1753                                 void *priv)
1754 {
1755         struct ffs_data *ffs = priv;
1756
1757         ENTER();
1758
1759         switch (type) {
1760         case FFS_DESCRIPTOR:
1761                 break;
1762
1763         case FFS_INTERFACE:
1764                 /*
1765                  * Interfaces are indexed from zero so if we
1766                  * encountered interface "n" then there are at least
1767                  * "n+1" interfaces.
1768                  */
1769                 if (*valuep >= ffs->interfaces_count)
1770                         ffs->interfaces_count = *valuep + 1;
1771                 break;
1772
1773         case FFS_STRING:
1774                 /*
1775                  * Strings are indexed from 1 (0 is magic ;) reserved
1776                  * for languages list or some such)
1777                  */
1778                 if (*valuep > ffs->strings_count)
1779                         ffs->strings_count = *valuep;
1780                 break;
1781
1782         case FFS_ENDPOINT:
1783                 /* Endpoints are indexed from 1 as well. */
1784                 if ((*valuep & USB_ENDPOINT_NUMBER_MASK) > ffs->eps_count)
1785                         ffs->eps_count = (*valuep & USB_ENDPOINT_NUMBER_MASK);
1786                 break;
1787         }
1788
1789         return 0;
1790 }
1791
1792 static int __ffs_data_got_descs(struct ffs_data *ffs,
1793                                 char *const _data, size_t len)
1794 {
1795         unsigned fs_count, hs_count;
1796         int fs_len, ret = -EINVAL;
1797         char *data = _data;
1798
1799         ENTER();
1800
1801         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_DESCRIPTORS_MAGIC ||
1802                      get_unaligned_le32(data + 4) != len))
1803                 goto error;
1804         fs_count = get_unaligned_le32(data +  8);
1805         hs_count = get_unaligned_le32(data + 12);
1806
1807         if (!fs_count && !hs_count)
1808                 goto einval;
1809
1810         data += 16;
1811         len  -= 16;
1812
1813         if (likely(fs_count)) {
1814                 fs_len = ffs_do_descs(fs_count, data, len,
1815                                       __ffs_data_do_entity, ffs);
1816                 if (unlikely(fs_len < 0)) {
1817                         ret = fs_len;
1818                         goto error;
1819                 }
1820
1821                 data += fs_len;
1822                 len  -= fs_len;
1823         } else {
1824                 fs_len = 0;
1825         }
1826
1827         if (likely(hs_count)) {
1828                 ret = ffs_do_descs(hs_count, data, len,
1829                                    __ffs_data_do_entity, ffs);
1830                 if (unlikely(ret < 0))
1831                         goto error;
1832         } else {
1833                 ret = 0;
1834         }
1835
1836         if (unlikely(len != ret))
1837                 goto einval;
1838
1839         ffs->raw_fs_descs_length = fs_len;
1840         ffs->raw_descs_length    = fs_len + ret;
1841         ffs->raw_descs           = _data;
1842         ffs->fs_descs_count      = fs_count;
1843         ffs->hs_descs_count      = hs_count;
1844
1845         return 0;
1846
1847 einval:
1848         ret = -EINVAL;
1849 error:
1850         kfree(_data);
1851         return ret;
1852 }
1853
1854 static int __ffs_data_got_strings(struct ffs_data *ffs,
1855                                   char *const _data, size_t len)
1856 {
1857         u32 str_count, needed_count, lang_count;
1858         struct usb_gadget_strings **stringtabs, *t;
1859         struct usb_string *strings, *s;
1860         const char *data = _data;
1861
1862         ENTER();
1863
1864         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
1865                      get_unaligned_le32(data + 4) != len))
1866                 goto error;
1867         str_count  = get_unaligned_le32(data + 8);
1868         lang_count = get_unaligned_le32(data + 12);
1869
1870         /* if one is zero the other must be zero */
1871         if (unlikely(!str_count != !lang_count))
1872                 goto error;
1873
1874         /* Do we have at least as many strings as descriptors need? */
1875         needed_count = ffs->strings_count;
1876         if (unlikely(str_count < needed_count))
1877                 goto error;
1878
1879         /*
1880          * If we don't need any strings just return and free all
1881          * memory.
1882          */
1883         if (!needed_count) {
1884                 kfree(_data);
1885                 return 0;
1886         }
1887
1888         /* Allocate everything in one chunk so there's less maintenance. */
1889         {
1890                 struct {
1891                         struct usb_gadget_strings *stringtabs[lang_count + 1];
1892                         struct usb_gadget_strings stringtab[lang_count];
1893                         struct usb_string strings[lang_count*(needed_count+1)];
1894                 } *d;
1895                 unsigned i = 0;
1896
1897                 d = kmalloc(sizeof *d, GFP_KERNEL);
1898                 if (unlikely(!d)) {
1899                         kfree(_data);
1900                         return -ENOMEM;
1901                 }
1902
1903                 stringtabs = d->stringtabs;
1904                 t = d->stringtab;
1905                 i = lang_count;
1906                 do {
1907                         *stringtabs++ = t++;
1908                 } while (--i);
1909                 *stringtabs = NULL;
1910
1911                 stringtabs = d->stringtabs;
1912                 t = d->stringtab;
1913                 s = d->strings;
1914                 strings = s;
1915         }
1916
1917         /* For each language */
1918         data += 16;
1919         len -= 16;
1920
1921         do { /* lang_count > 0 so we can use do-while */
1922                 unsigned needed = needed_count;
1923
1924                 if (unlikely(len < 3))
1925                         goto error_free;
1926                 t->language = get_unaligned_le16(data);
1927                 t->strings  = s;
1928                 ++t;
1929
1930                 data += 2;
1931                 len -= 2;
1932
1933                 /* For each string */
1934                 do { /* str_count > 0 so we can use do-while */
1935                         size_t length = strnlen(data, len);
1936
1937                         if (unlikely(length == len))
1938                                 goto error_free;
1939
1940                         /*
1941                          * User may provide more strings then we need,
1942                          * if that's the case we simply ignore the
1943                          * rest
1944                          */
1945                         if (likely(needed)) {
1946                                 /*
1947                                  * s->id will be set while adding
1948                                  * function to configuration so for
1949                                  * now just leave garbage here.
1950                                  */
1951                                 s->s = data;
1952                                 --needed;
1953                                 ++s;
1954                         }
1955
1956                         data += length + 1;
1957                         len -= length + 1;
1958                 } while (--str_count);
1959
1960                 s->id = 0;   /* terminator */
1961                 s->s = NULL;
1962                 ++s;
1963
1964         } while (--lang_count);
1965
1966         /* Some garbage left? */
1967         if (unlikely(len))
1968                 goto error_free;
1969
1970         /* Done! */
1971         ffs->stringtabs = stringtabs;
1972         ffs->raw_strings = _data;
1973
1974         return 0;
1975
1976 error_free:
1977         kfree(stringtabs);
1978 error:
1979         kfree(_data);
1980         return -EINVAL;
1981 }
1982
1983
1984 /* Events handling and management *******************************************/
1985
1986 static void __ffs_event_add(struct ffs_data *ffs,
1987                             enum usb_functionfs_event_type type)
1988 {
1989         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
1990         int neg = 0;
1991
1992         /*
1993          * Abort any unhandled setup
1994          *
1995          * We do not need to worry about some cmpxchg() changing value
1996          * of ffs->setup_state without holding the lock because when
1997          * state is FFS_SETUP_PENDING cmpxchg() in several places in
1998          * the source does nothing.
1999          */
2000         if (ffs->setup_state == FFS_SETUP_PENDING)
2001                 ffs->setup_state = FFS_SETUP_CANCELED;
2002
2003         switch (type) {
2004         case FUNCTIONFS_RESUME:
2005                 rem_type2 = FUNCTIONFS_SUSPEND;
2006                 /* FALL THROUGH */
2007         case FUNCTIONFS_SUSPEND:
2008         case FUNCTIONFS_SETUP:
2009                 rem_type1 = type;
2010                 /* Discard all similar events */
2011                 break;
2012
2013         case FUNCTIONFS_BIND:
2014         case FUNCTIONFS_UNBIND:
2015         case FUNCTIONFS_DISABLE:
2016         case FUNCTIONFS_ENABLE:
2017                 /* Discard everything other then power management. */
2018                 rem_type1 = FUNCTIONFS_SUSPEND;
2019                 rem_type2 = FUNCTIONFS_RESUME;
2020                 neg = 1;
2021                 break;
2022
2023         default:
2024                 BUG();
2025         }
2026
2027         {
2028                 u8 *ev  = ffs->ev.types, *out = ev;
2029                 unsigned n = ffs->ev.count;
2030                 for (; n; --n, ++ev)
2031                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2032                                 *out++ = *ev;
2033                         else
2034                                 pr_vdebug("purging event %d\n", *ev);
2035                 ffs->ev.count = out - ffs->ev.types;
2036         }
2037
2038         pr_vdebug("adding event %d\n", type);
2039         ffs->ev.types[ffs->ev.count++] = type;
2040         wake_up_locked(&ffs->ev.waitq);
2041 }
2042
2043 static void ffs_event_add(struct ffs_data *ffs,
2044                           enum usb_functionfs_event_type type)
2045 {
2046         unsigned long flags;
2047         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2048         __ffs_event_add(ffs, type);
2049         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2050 }
2051
2052
2053 /* Bind/unbind USB function hooks *******************************************/
2054
2055 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2056                                     struct usb_descriptor_header *desc,
2057                                     void *priv)
2058 {
2059         struct usb_endpoint_descriptor *ds = (void *)desc;
2060         struct ffs_function *func = priv;
2061         struct ffs_ep *ffs_ep;
2062
2063         /*
2064          * If hs_descriptors is not NULL then we are reading hs
2065          * descriptors now
2066          */
2067         const int isHS = func->function.hs_descriptors != NULL;
2068         unsigned idx;
2069
2070         if (type != FFS_DESCRIPTOR)
2071                 return 0;
2072
2073         if (isHS)
2074                 func->function.hs_descriptors[(long)valuep] = desc;
2075         else
2076                 func->function.fs_descriptors[(long)valuep]    = desc;
2077
2078         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2079                 return 0;
2080
2081         idx = (ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK) - 1;
2082         ffs_ep = func->eps + idx;
2083
2084         if (unlikely(ffs_ep->descs[isHS])) {
2085                 pr_vdebug("two %sspeed descriptors for EP %d\n",
2086                           isHS ? "high" : "full",
2087                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2088                 return -EINVAL;
2089         }
2090         ffs_ep->descs[isHS] = ds;
2091
2092         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2093         if (ffs_ep->ep) {
2094                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2095                 if (!ds->wMaxPacketSize)
2096                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2097         } else {
2098                 struct usb_request *req;
2099                 struct usb_ep *ep;
2100
2101                 pr_vdebug("autoconfig\n");
2102                 ep = usb_ep_autoconfig(func->gadget, ds);
2103                 if (unlikely(!ep))
2104                         return -ENOTSUPP;
2105                 ep->driver_data = func->eps + idx;
2106
2107                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2108                 if (unlikely(!req))
2109                         return -ENOMEM;
2110
2111                 ffs_ep->ep  = ep;
2112                 ffs_ep->req = req;
2113                 func->eps_revmap[ds->bEndpointAddress &
2114                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2115         }
2116         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2117
2118         return 0;
2119 }
2120
2121 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2122                                    struct usb_descriptor_header *desc,
2123                                    void *priv)
2124 {
2125         struct ffs_function *func = priv;
2126         unsigned idx;
2127         u8 newValue;
2128
2129         switch (type) {
2130         default:
2131         case FFS_DESCRIPTOR:
2132                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2133                 return 0;
2134
2135         case FFS_INTERFACE:
2136                 idx = *valuep;
2137                 if (func->interfaces_nums[idx] < 0) {
2138                         int id = usb_interface_id(func->conf, &func->function);
2139                         if (unlikely(id < 0))
2140                                 return id;
2141                         func->interfaces_nums[idx] = id;
2142                 }
2143                 newValue = func->interfaces_nums[idx];
2144                 break;
2145
2146         case FFS_STRING:
2147                 /* String' IDs are allocated when fsf_data is bound to cdev */
2148                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2149                 break;
2150
2151         case FFS_ENDPOINT:
2152                 /*
2153                  * USB_DT_ENDPOINT are handled in
2154                  * __ffs_func_bind_do_descs().
2155                  */
2156                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2157                         return 0;
2158
2159                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2160                 if (unlikely(!func->eps[idx].ep))
2161                         return -EINVAL;
2162
2163                 {
2164                         struct usb_endpoint_descriptor **descs;
2165                         descs = func->eps[idx].descs;
2166                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2167                 }
2168                 break;
2169         }
2170
2171         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2172         *valuep = newValue;
2173         return 0;
2174 }
2175
2176 static int ffs_func_bind(struct usb_configuration *c,
2177                          struct usb_function *f)
2178 {
2179         struct ffs_function *func = ffs_func_from_usb(f);
2180         struct ffs_data *ffs = func->ffs;
2181
2182         const int full = !!func->ffs->fs_descs_count;
2183         const int high = gadget_is_dualspeed(func->gadget) &&
2184                 func->ffs->hs_descs_count;
2185
2186         int ret;
2187
2188         /* Make it a single chunk, less management later on */
2189         struct {
2190                 struct ffs_ep eps[ffs->eps_count];
2191                 struct usb_descriptor_header
2192                         *fs_descs[full ? ffs->fs_descs_count + 1 : 0];
2193                 struct usb_descriptor_header
2194                         *hs_descs[high ? ffs->hs_descs_count + 1 : 0];
2195                 short inums[ffs->interfaces_count];
2196                 char raw_descs[high ? ffs->raw_descs_length
2197                                     : ffs->raw_fs_descs_length];
2198         } *data;
2199
2200         ENTER();
2201
2202         /* Only high speed but not supported by gadget? */
2203         if (unlikely(!(full | high)))
2204                 return -ENOTSUPP;
2205
2206         /* Allocate */
2207         data = kmalloc(sizeof *data, GFP_KERNEL);
2208         if (unlikely(!data))
2209                 return -ENOMEM;
2210
2211         /* Zero */
2212         memset(data->eps, 0, sizeof data->eps);
2213         memcpy(data->raw_descs, ffs->raw_descs + 16, sizeof data->raw_descs);
2214         memset(data->inums, 0xff, sizeof data->inums);
2215         for (ret = ffs->eps_count; ret; --ret)
2216                 data->eps[ret].num = -1;
2217
2218         /* Save pointers */
2219         func->eps             = data->eps;
2220         func->interfaces_nums = data->inums;
2221
2222         /*
2223          * Go through all the endpoint descriptors and allocate
2224          * endpoints first, so that later we can rewrite the endpoint
2225          * numbers without worrying that it may be described later on.
2226          */
2227         if (likely(full)) {
2228                 func->function.fs_descriptors = data->fs_descs;
2229                 ret = ffs_do_descs(ffs->fs_descs_count,
2230                                    data->raw_descs,
2231                                    sizeof data->raw_descs,
2232                                    __ffs_func_bind_do_descs, func);
2233                 if (unlikely(ret < 0))
2234                         goto error;
2235         } else {
2236                 ret = 0;
2237         }
2238
2239         if (likely(high)) {
2240                 func->function.hs_descriptors = data->hs_descs;
2241                 ret = ffs_do_descs(ffs->hs_descs_count,
2242                                    data->raw_descs + ret,
2243                                    (sizeof data->raw_descs) - ret,
2244                                    __ffs_func_bind_do_descs, func);
2245                 if (unlikely(ret < 0))
2246                         goto error;
2247         }
2248
2249         /*
2250          * Now handle interface numbers allocation and interface and
2251          * endpoint numbers rewriting.  We can do that in one go
2252          * now.
2253          */
2254         ret = ffs_do_descs(ffs->fs_descs_count +
2255                            (high ? ffs->hs_descs_count : 0),
2256                            data->raw_descs, sizeof data->raw_descs,
2257                            __ffs_func_bind_do_nums, func);
2258         if (unlikely(ret < 0))
2259                 goto error;
2260
2261         /* And we're done */
2262         ffs_event_add(ffs, FUNCTIONFS_BIND);
2263         return 0;
2264
2265 error:
2266         /* XXX Do we need to release all claimed endpoints here? */
2267         return ret;
2268 }
2269
2270
2271 /* Other USB function hooks *************************************************/
2272
2273 static void ffs_func_unbind(struct usb_configuration *c,
2274                             struct usb_function *f)
2275 {
2276         struct ffs_function *func = ffs_func_from_usb(f);
2277         struct ffs_data *ffs = func->ffs;
2278
2279         ENTER();
2280
2281         if (ffs->func == func) {
2282                 ffs_func_eps_disable(func);
2283                 ffs->func = NULL;
2284         }
2285
2286         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
2287
2288         ffs_func_free(func);
2289 }
2290
2291 static int ffs_func_set_alt(struct usb_function *f,
2292                             unsigned interface, unsigned alt)
2293 {
2294         struct ffs_function *func = ffs_func_from_usb(f);
2295         struct ffs_data *ffs = func->ffs;
2296         int ret = 0, intf;
2297
2298         if (alt != (unsigned)-1) {
2299                 intf = ffs_func_revmap_intf(func, interface);
2300                 if (unlikely(intf < 0))
2301                         return intf;
2302         }
2303
2304         if (ffs->func)
2305                 ffs_func_eps_disable(ffs->func);
2306
2307         if (ffs->state != FFS_ACTIVE)
2308                 return -ENODEV;
2309
2310         if (alt == (unsigned)-1) {
2311                 ffs->func = NULL;
2312                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2313                 return 0;
2314         }
2315
2316         ffs->func = func;
2317         ret = ffs_func_eps_enable(func);
2318         if (likely(ret >= 0))
2319                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2320         return ret;
2321 }
2322
2323 static void ffs_func_disable(struct usb_function *f)
2324 {
2325         ffs_func_set_alt(f, 0, (unsigned)-1);
2326 }
2327
2328 static int ffs_func_setup(struct usb_function *f,
2329                           const struct usb_ctrlrequest *creq)
2330 {
2331         struct ffs_function *func = ffs_func_from_usb(f);
2332         struct ffs_data *ffs = func->ffs;
2333         unsigned long flags;
2334         int ret;
2335
2336         ENTER();
2337
2338         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2339         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2340         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2341         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
2342         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
2343
2344         /*
2345          * Most requests directed to interface go through here
2346          * (notable exceptions are set/get interface) so we need to
2347          * handle them.  All other either handled by composite or
2348          * passed to usb_configuration->setup() (if one is set).  No
2349          * matter, we will handle requests directed to endpoint here
2350          * as well (as it's straightforward) but what to do with any
2351          * other request?
2352          */
2353         if (ffs->state != FFS_ACTIVE)
2354                 return -ENODEV;
2355
2356         switch (creq->bRequestType & USB_RECIP_MASK) {
2357         case USB_RECIP_INTERFACE:
2358                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
2359                 if (unlikely(ret < 0))
2360                         return ret;
2361                 break;
2362
2363         case USB_RECIP_ENDPOINT:
2364                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
2365                 if (unlikely(ret < 0))
2366                         return ret;
2367                 break;
2368
2369         default:
2370                 return -EOPNOTSUPP;
2371         }
2372
2373         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2374         ffs->ev.setup = *creq;
2375         ffs->ev.setup.wIndex = cpu_to_le16(ret);
2376         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
2377         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2378
2379         return 0;
2380 }
2381
2382 static void ffs_func_suspend(struct usb_function *f)
2383 {
2384         ENTER();
2385         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
2386 }
2387
2388 static void ffs_func_resume(struct usb_function *f)
2389 {
2390         ENTER();
2391         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
2392 }
2393
2394
2395 /* Endpoint and interface numbers reverse mapping ***************************/
2396
2397 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
2398 {
2399         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
2400         return num ? num : -EDOM;
2401 }
2402
2403 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
2404 {
2405         short *nums = func->interfaces_nums;
2406         unsigned count = func->ffs->interfaces_count;
2407
2408         for (; count; --count, ++nums) {
2409                 if (*nums >= 0 && *nums == intf)
2410                         return nums - func->interfaces_nums;
2411         }
2412
2413         return -EDOM;
2414 }
2415
2416
2417 /* Misc helper functions ****************************************************/
2418
2419 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
2420 {
2421         return nonblock
2422                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
2423                 : mutex_lock_interruptible(mutex);
2424 }
2425
2426 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
2427 {
2428         char *data;
2429
2430         if (unlikely(!len))
2431                 return NULL;
2432
2433         data = kmalloc(len, GFP_KERNEL);
2434         if (unlikely(!data))
2435                 return ERR_PTR(-ENOMEM);
2436
2437         if (unlikely(__copy_from_user(data, buf, len))) {
2438                 kfree(data);
2439                 return ERR_PTR(-EFAULT);
2440         }
2441
2442         pr_vdebug("Buffer from user space:\n");
2443         ffs_dump_mem("", data, len);
2444
2445         return data;
2446 }