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 <m.nazarewicz@samsung.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 <asm/unaligned.h>
  25
  26 #include <linux/usb/composite.h>
  27 #include <linux/usb/functionfs.h>
  28
  29
  30 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  31
  32
  33 /* Debugging ****************************************************************/
  34
  35 #ifdef VERBOSE_DEBUG
  36 #  define pr_vdebug pr_debug
  37 #  define ffs_dump_mem(prefix, ptr, len) \
  38         print_hex_dump_bytes(pr_fmt(prefix ": "), DUMP_PREFIX_NONE, ptr, len)
  39 #else
  40 #  define pr_vdebug(...)                 do { } while (0)
  41 #  define ffs_dump_mem(prefix, ptr, len) do { } while (0)
  42 #endif /* VERBOSE_DEBUG */
  43
  44 #define ENTER()    pr_vdebug("%s()\n", __func__)
  45
  46
  47 /* The data structure and setup file ****************************************/
  48
  49 enum ffs_state {
  50         /*
  51          * Waiting for descriptors and strings.
  52          *
  53          * In this state no open(2), read(2) or write(2) on epfiles
  54          * may succeed (which should not be the problem as there
  55          * should be no such files opened in the first place).
  56          */
  57         FFS_READ_DESCRIPTORS,
  58         FFS_READ_STRINGS,
  59
  60         /*
  61          * We've got descriptors and strings.  We are or have called
  62          * functionfs_ready_callback().  functionfs_bind() may have
  63          * been called but we don't know.
  64          *
  65          * This is the only state in which operations on epfiles may
  66          * succeed.
  67          */
  68         FFS_ACTIVE,
  69
  70         /*
  71          * All endpoints have been closed.  This state is also set if
  72          * we encounter an unrecoverable error.  The only
  73          * unrecoverable error is situation when after reading strings
  74          * from user space we fail to initialise epfiles or
  75          * functionfs_ready_callback() returns with error (<0).
  76          *
  77          * In this state no open(2), read(2) or write(2) (both on ep0
  78          * as well as epfile) may succeed (at this point epfiles are
  79          * unlinked and all closed so this is not a problem; ep0 is
  80          * also closed but ep0 file exists and so open(2) on ep0 must
  81          * fail).
  82          */
  83         FFS_CLOSING
  84 };
  85
  86
  87 enum ffs_setup_state {
  88         /* There is no setup request pending. */
  89         FFS_NO_SETUP,
  90         /*
  91          * User has read events and there was a setup request event
  92          * there.  The next read/write on ep0 will handle the
  93          * request.
  94          */
  95         FFS_SETUP_PENDING,
  96         /*
  97          * There was event pending but before user space handled it
  98          * some other event was introduced which canceled existing
  99          * setup.  If this state is set read/write on ep0 return
 100          * -EIDRM.  This state is only set when adding event.
 101          */
 102         FFS_SETUP_CANCELED
 103 };
 104
 105
 106
 107 struct ffs_epfile;
 108 struct ffs_function;
 109
 110 struct ffs_data {
 111         struct usb_gadget               *gadget;
 112
 113         /*
 114          * Protect access read/write operations, only one read/write
 115          * at a time.  As a consequence protects ep0req and company.
 116          * While setup request is being processed (queued) this is
 117          * held.
 118          */
 119         struct mutex                    mutex;
 120
 121         /*
 122          * Protect access to endpoint related structures (basically
 123          * usb_ep_queue(), usb_ep_dequeue(), etc. calls) except for
 124          * endpoint zero.
 125          */
 126         spinlock_t                      eps_lock;
 127
 128         /*
 129          * XXX REVISIT do we need our own request? Since we are not
 130          * handling setup requests immediately user space may be so
 131          * slow that another setup will be sent to the gadget but this
 132          * time not to us but another function and then there could be
 133          * a race.  Is that the case? Or maybe we can use cdev->req
 134          * after all, maybe we just need some spinlock for that?
 135          */
 136         struct usb_request              *ep0req;                /* P: mutex */
 137         struct completion               ep0req_completion;      /* P: mutex */
 138         int                             ep0req_status;          /* P: mutex */
 139
 140         /* reference counter */
 141         atomic_t                        ref;
 142         /* how many files are opened (EP0 and others) */
 143         atomic_t                        opened;
 144
 145         /* EP0 state */
 146         enum ffs_state                  state;
 147
 148         /*
 149          * Possible transitions:
 150          * + FFS_NO_SETUP       -> FFS_SETUP_PENDING  -- P: ev.waitq.lock
 151          *               happens only in ep0 read which is P: mutex
 152          * + FFS_SETUP_PENDING  -> FFS_NO_SETUP       -- P: ev.waitq.lock
 153          *               happens only in ep0 i/o  which is P: mutex
 154          * + FFS_SETUP_PENDING  -> FFS_SETUP_CANCELED -- P: ev.waitq.lock
 155          * + FFS_SETUP_CANCELED -> FFS_NO_SETUP       -- cmpxchg
 156          */
 157         enum ffs_setup_state            setup_state;
 158
 159 #define FFS_SETUP_STATE(ffs)                                    \
 160         ((enum ffs_setup_state)cmpxchg(&(ffs)->setup_state,     \
 161                                        FFS_SETUP_CANCELED, FFS_NO_SETUP))
 162
 163         /* Events & such. */
 164         struct {
 165                 u8                              types[4];
 166                 unsigned short                  count;
 167                 /* XXX REVISIT need to update it in some places, or do we? */
 168                 unsigned short                  can_stall;
 169                 struct usb_ctrlrequest          setup;
 170
 171                 wait_queue_head_t               waitq;
 172         } ev; /* the whole structure, P: ev.waitq.lock */
 173
 174         /* Flags */
 175         unsigned long                   flags;
 176 #define FFS_FL_CALL_CLOSED_CALLBACK 0
 177 #define FFS_FL_BOUND                1
 178
 179         /* Active function */
 180         struct ffs_function             *func;
 181
 182         /*
 183          * Device name, write once when file system is mounted.
 184          * Intended for user to read if she wants.
 185          */
 186         const char                      *dev_name;
 187         /* Private data for our user (ie. gadget).  Managed by user. */
 188         void                            *private_data;
 189
 190         /* filled by __ffs_data_got_descs() */
 191         /*
 192          * Real descriptors are 16 bytes after raw_descs (so you need
 193          * to skip 16 bytes (ie. ffs->raw_descs + 16) to get to the
 194          * first full speed descriptor).  raw_descs_length and
 195          * raw_fs_descs_length do not have those 16 bytes added.
 196          */
 197         const void                      *raw_descs;
 198         unsigned                        raw_descs_length;
 199         unsigned                        raw_fs_descs_length;
 200         unsigned                        fs_descs_count;
 201         unsigned                        hs_descs_count;
 202
 203         unsigned short                  strings_count;
 204         unsigned short                  interfaces_count;
 205         unsigned short                  eps_count;
 206         unsigned short                  _pad1;
 207
 208         /* filled by __ffs_data_got_strings() */
 209         /* ids in stringtabs are set in functionfs_bind() */
 210         const void                      *raw_strings;
 211         struct usb_gadget_strings       **stringtabs;
 212
 213         /*
 214          * File system's super block, write once when file system is
 215          * mounted.
 216          */
 217         struct super_block              *sb;
 218
 219         /* File permissions, written once when fs is mounted */
 220         struct ffs_file_perms {
 221                 umode_t                         mode;
 222                 uid_t                           uid;
 223                 gid_t                           gid;
 224         }                               file_perms;
 225
 226         /*
 227          * The endpoint files, filled by ffs_epfiles_create(),
 228          * destroyed by ffs_epfiles_destroy().
 229          */
 230         struct ffs_epfile               *epfiles;
 231 };
 232
 233 /* Reference counter handling */
 234 static void ffs_data_get(struct ffs_data *ffs);
 235 static void ffs_data_put(struct ffs_data *ffs);
 236 /* Creates new ffs_data object. */
 237 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
 238
 239 /* Opened counter handling. */
 240 static void ffs_data_opened(struct ffs_data *ffs);
 241 static void ffs_data_closed(struct ffs_data *ffs);
 242
 243 /* Called with ffs->mutex held; take over ownership of data. */
 244 static int __must_check
 245 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
 246 static int __must_check
 247 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
 248
 249
 250 /* The function structure ***************************************************/
 251
 252 struct ffs_ep;
 253
 254 struct ffs_function {
 255         struct usb_configuration        *conf;
 256         struct usb_gadget               *gadget;
 257         struct ffs_data                 *ffs;
 258
 259         struct ffs_ep                   *eps;
 260         u8                              eps_revmap[16];
 261         short                           *interfaces_nums;
 262
 263         struct usb_function             function;
 264 };
 265
 266
 267 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
 268 {
 269         return container_of(f, struct ffs_function, function);
 270 }
 271
 272 static void ffs_func_free(struct ffs_function *func);
 273
 274 static void ffs_func_eps_disable(struct ffs_function *func);
 275 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
 276
 277 static int ffs_func_bind(struct usb_configuration *,
 278                          struct usb_function *);
 279 static void ffs_func_unbind(struct usb_configuration *,
 280                             struct usb_function *);
 281 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 282 static void ffs_func_disable(struct usb_function *);
 283 static int ffs_func_setup(struct usb_function *,
 284                           const struct usb_ctrlrequest *);
 285 static void ffs_func_suspend(struct usb_function *);
 286 static void ffs_func_resume(struct usb_function *);
 287
 288
 289 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 290 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 291
 292
 293 /* The endpoints structures *************************************************/
 294
 295 struct ffs_ep {
 296         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 297         struct usb_request              *req;   /* P: epfile->mutex */
 298
 299         /* [0]: full speed, [1]: high speed */
 300         struct usb_endpoint_descriptor  *descs[2];
 301
 302         u8                              num;
 303
 304         int                             status; /* P: epfile->mutex */
 305 };
 306
 307 struct ffs_epfile {
 308         /* Protects ep->ep and ep->req. */
 309         struct mutex                    mutex;
 310         wait_queue_head_t               wait;
 311
 312         struct ffs_data                 *ffs;
 313         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 314
 315         struct dentry                   *dentry;
 316
 317         char                            name[5];
 318
 319         unsigned char                   in;     /* P: ffs->eps_lock */
 320         unsigned char                   isoc;   /* P: ffs->eps_lock */
 321
 322         unsigned char                   _pad;
 323 };
 324
 325 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 326 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 327
 328 static struct inode *__must_check
 329 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 330                    const struct file_operations *fops,
 331                    struct dentry **dentry_p);
 332
 333
 334 /* Misc helper functions ****************************************************/
 335
 336 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 337         __attribute__((warn_unused_result, nonnull));
 338 static char *ffs_prepare_buffer(const char * __user buf, size_t len)
 339         __attribute__((warn_unused_result, nonnull));
 340
 341
 342 /* Control file aka ep0 *****************************************************/
 343
 344 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 345 {
 346         struct ffs_data *ffs = req->context;
 347
 348         complete_all(&ffs->ep0req_completion);
 349 }
 350
 351 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 352 {
 353         struct usb_request *req = ffs->ep0req;
 354         int ret;
 355
 356         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 357
 358         spin_unlock_irq(&ffs->ev.waitq.lock);
 359
 360         req->buf      = data;
 361         req->length   = len;
 362
 363         /*
 364          * UDC layer requires to provide a buffer even for ZLP, but should
 365          * not use it at all. Let's provide some poisoned pointer to catch
 366          * possible bug in the driver.
 367          */
 368         if (req->buf == NULL)
 369                 req->buf = (void *)0xDEADBABE;
 370
 371         INIT_COMPLETION(ffs->ep0req_completion);
 372
 373         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 374         if (unlikely(ret < 0))
 375                 return ret;
 376
 377         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 378         if (unlikely(ret)) {
 379                 usb_ep_dequeue(ffs->gadget->ep0, req);
 380                 return -EINTR;
 381         }
 382
 383         ffs->setup_state = FFS_NO_SETUP;
 384         return ffs->ep0req_status;
 385 }
 386
 387 static int __ffs_ep0_stall(struct ffs_data *ffs)
 388 {
 389         if (ffs->ev.can_stall) {
 390                 pr_vdebug("ep0 stall\n");
 391                 usb_ep_set_halt(ffs->gadget->ep0);
 392                 ffs->setup_state = FFS_NO_SETUP;
 393                 return -EL2HLT;
 394         } else {
 395                 pr_debug("bogus ep0 stall!\n");
 396                 return -ESRCH;
 397         }
 398 }
 399
 400 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 401                              size_t len, loff_t *ptr)
 402 {
 403         struct ffs_data *ffs = file->private_data;
 404         ssize_t ret;
 405         char *data;
 406
 407         ENTER();
 408
 409         /* Fast check if setup was canceled */
 410         if (FFS_SETUP_STATE(ffs) == FFS_SETUP_CANCELED)
 411                 return -EIDRM;
 412
 413         /* Acquire mutex */
 414         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 415         if (unlikely(ret < 0))
 416                 return ret;
 417
 418         /* Check state */
 419         switch (ffs->state) {
 420         case FFS_READ_DESCRIPTORS:
 421         case FFS_READ_STRINGS:
 422                 /* Copy data */
 423                 if (unlikely(len < 16)) {
 424                         ret = -EINVAL;
 425                         break;
 426                 }
 427
 428                 data = ffs_prepare_buffer(buf, len);
 429                 if (IS_ERR(data)) {
 430                         ret = PTR_ERR(data);
 431                         break;
 432                 }
 433
 434                 /* Handle data */
 435                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 436                         pr_info("read descriptors\n");
 437                         ret = __ffs_data_got_descs(ffs, data, len);
 438                         if (unlikely(ret < 0))
 439                                 break;
 440
 441                         ffs->state = FFS_READ_STRINGS;
 442                         ret = len;
 443                 } else {
 444                         pr_info("read strings\n");
 445                         ret = __ffs_data_got_strings(ffs, data, len);
 446                         if (unlikely(ret < 0))
 447                                 break;
 448
 449                         ret = ffs_epfiles_create(ffs);
 450                         if (unlikely(ret)) {
 451                                 ffs->state = FFS_CLOSING;
 452                                 break;
 453                         }
 454
 455                         ffs->state = FFS_ACTIVE;
 456                         mutex_unlock(&ffs->mutex);
 457
 458                         ret = functionfs_ready_callback(ffs);
 459                         if (unlikely(ret < 0)) {
 460                                 ffs->state = FFS_CLOSING;
 461                                 return ret;
 462                         }
 463
 464                         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
 465                         return len;
 466                 }
 467                 break;
 468
 469         case FFS_ACTIVE:
 470                 data = NULL;
 471                 /*
 472                  * We're called from user space, we can use _irq
 473                  * rather then _irqsave
 474                  */
 475                 spin_lock_irq(&ffs->ev.waitq.lock);
 476                 switch (FFS_SETUP_STATE(ffs)) {
 477                 case FFS_SETUP_CANCELED:
 478                         ret = -EIDRM;
 479                         goto done_spin;
 480
 481                 case FFS_NO_SETUP:
 482                         ret = -ESRCH;
 483                         goto done_spin;
 484
 485                 case FFS_SETUP_PENDING:
 486                         break;
 487                 }
 488
 489                 /* FFS_SETUP_PENDING */
 490                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 491                         spin_unlock_irq(&ffs->ev.waitq.lock);
 492                         ret = __ffs_ep0_stall(ffs);
 493                         break;
 494                 }
 495
 496                 /* FFS_SETUP_PENDING and not stall */
 497                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 498
 499                 spin_unlock_irq(&ffs->ev.waitq.lock);
 500
 501                 data = ffs_prepare_buffer(buf, len);
 502                 if (IS_ERR(data)) {
 503                         ret = PTR_ERR(data);
 504                         break;
 505                 }
 506
 507                 spin_lock_irq(&ffs->ev.waitq.lock);
 508
 509                 /*
 510                  * We are guaranteed to be still in FFS_ACTIVE state
 511                  * but the state of setup could have changed from
 512                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELED so we need
 513                  * to check for that.  If that happened we copied data
 514                  * from user space in vain but it's unlikely.
 515                  *
 516                  * For sure we are not in FFS_NO_SETUP since this is
 517                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 518                  * transition can be performed and it's protected by
 519                  * mutex.
 520                  */
 521                 if (FFS_SETUP_STATE(ffs) == FFS_SETUP_CANCELED) {
 522                         ret = -EIDRM;
 523 done_spin:
 524                         spin_unlock_irq(&ffs->ev.waitq.lock);
 525                 } else {
 526                         /* unlocks spinlock */
 527                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 528                 }
 529                 kfree(data);
 530                 break;
 531
 532         default:
 533                 ret = -EBADFD;
 534                 break;
 535         }
 536
 537         mutex_unlock(&ffs->mutex);
 538         return ret;
 539 }
 540
 541 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 542                                      size_t n)
 543 {
 544         /*
 545          * We are holding ffs->ev.waitq.lock and ffs->mutex and we need
 546          * to release them.
 547          */
 548         struct usb_functionfs_event events[n];
 549         unsigned i = 0;
 550
 551         memset(events, 0, sizeof events);
 552
 553         do {
 554                 events[i].type = ffs->ev.types[i];
 555                 if (events[i].type == FUNCTIONFS_SETUP) {
 556                         events[i].u.setup = ffs->ev.setup;
 557                         ffs->setup_state = FFS_SETUP_PENDING;
 558                 }
 559         } while (++i < n);
 560
 561         if (n < ffs->ev.count) {
 562                 ffs->ev.count -= n;
 563                 memmove(ffs->ev.types, ffs->ev.types + n,
 564                         ffs->ev.count * sizeof *ffs->ev.types);
 565         } else {
 566                 ffs->ev.count = 0;
 567         }
 568
 569         spin_unlock_irq(&ffs->ev.waitq.lock);
 570         mutex_unlock(&ffs->mutex);
 571
 572         return unlikely(__copy_to_user(buf, events, sizeof events))
 573                 ? -EFAULT : sizeof events;
 574 }
 575
 576 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 577                             size_t len, loff_t *ptr)
 578 {
 579         struct ffs_data *ffs = file->private_data;
 580         char *data = NULL;
 581         size_t n;
 582         int ret;
 583
 584         ENTER();
 585
 586         /* Fast check if setup was canceled */
 587         if (FFS_SETUP_STATE(ffs) == FFS_SETUP_CANCELED)
 588                 return -EIDRM;
 589
 590         /* Acquire mutex */
 591         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 592         if (unlikely(ret < 0))
 593                 return ret;
 594
 595         /* Check state */
 596         if (ffs->state != FFS_ACTIVE) {
 597                 ret = -EBADFD;
 598                 goto done_mutex;
 599         }
 600
 601         /*
 602          * We're called from user space, we can use _irq rather then
 603          * _irqsave
 604          */
 605         spin_lock_irq(&ffs->ev.waitq.lock);
 606
 607         switch (FFS_SETUP_STATE(ffs)) {
 608         case FFS_SETUP_CANCELED:
 609                 ret = -EIDRM;
 610                 break;
 611
 612         case FFS_NO_SETUP:
 613                 n = len / sizeof(struct usb_functionfs_event);
 614                 if (unlikely(!n)) {
 615                         ret = -EINVAL;
 616                         break;
 617                 }
 618
 619                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 620                         ret = -EAGAIN;
 621                         break;
 622                 }
 623
 624                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 625                                                         ffs->ev.count)) {
 626                         ret = -EINTR;
 627                         break;
 628                 }
 629
 630                 return __ffs_ep0_read_events(ffs, buf,
 631                                              min(n, (size_t)ffs->ev.count));
 632
 633         case FFS_SETUP_PENDING:
 634                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 635                         spin_unlock_irq(&ffs->ev.waitq.lock);
 636                         ret = __ffs_ep0_stall(ffs);
 637                         goto done_mutex;
 638                 }
 639
 640                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 641
 642                 spin_unlock_irq(&ffs->ev.waitq.lock);
 643
 644                 if (likely(len)) {
 645                         data = kmalloc(len, GFP_KERNEL);
 646                         if (unlikely(!data)) {
 647                                 ret = -ENOMEM;
 648                                 goto done_mutex;
 649                         }
 650                 }
 651
 652                 spin_lock_irq(&ffs->ev.waitq.lock);
 653
 654                 /* See ffs_ep0_write() */
 655                 if (FFS_SETUP_STATE(ffs) == FFS_SETUP_CANCELED) {
 656                         ret = -EIDRM;
 657                         break;
 658                 }
 659
 660                 /* unlocks spinlock */
 661                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 662                 if (likely(ret > 0) && unlikely(__copy_to_user(buf, data, len)))
 663                         ret = -EFAULT;
 664                 goto done_mutex;
 665
 666         default:
 667                 ret = -EBADFD;
 668                 break;
 669         }
 670
 671         spin_unlock_irq(&ffs->ev.waitq.lock);
 672 done_mutex:
 673         mutex_unlock(&ffs->mutex);
 674         kfree(data);
 675         return ret;
 676 }
 677
 678 static int ffs_ep0_open(struct inode *inode, struct file *file)
 679 {
 680         struct ffs_data *ffs = inode->i_private;
 681
 682         ENTER();
 683
 684         if (unlikely(ffs->state == FFS_CLOSING))
 685                 return -EBUSY;
 686
 687         file->private_data = ffs;
 688         ffs_data_opened(ffs);
 689
 690         return 0;
 691 }
 692
 693 static int ffs_ep0_release(struct inode *inode, struct file *file)
 694 {
 695         struct ffs_data *ffs = file->private_data;
 696
 697         ENTER();
 698
 699         ffs_data_closed(ffs);
 700
 701         return 0;
 702 }
 703
 704 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 705 {
 706         struct ffs_data *ffs = file->private_data;
 707         struct usb_gadget *gadget = ffs->gadget;
 708         long ret;
 709
 710         ENTER();
 711
 712         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 713                 struct ffs_function *func = ffs->func;
 714                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 715         } else if (gadget->ops->ioctl) {
 716                 ret = gadget->ops->ioctl(gadget, code, value);
 717         } else {
 718                 ret = -ENOTTY;
 719         }
 720
 721         return ret;
 722 }
 723
 724 static const struct file_operations ffs_ep0_operations = {
 725         .owner =        THIS_MODULE,
 726         .llseek =       no_llseek,
 727
 728         .open =         ffs_ep0_open,
 729         .write =        ffs_ep0_write,
 730         .read =         ffs_ep0_read,
 731         .release =      ffs_ep0_release,
 732         .unlocked_ioctl =       ffs_ep0_ioctl,
 733 };
 734
 735
 736 /* "Normal" endpoints operations ********************************************/
 737
 738 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 739 {
 740         ENTER();
 741         if (likely(req->context)) {
 742                 struct ffs_ep *ep = _ep->driver_data;
 743                 ep->status = req->status ? req->status : req->actual;
 744                 complete(req->context);
 745         }
 746 }
 747
 748 static ssize_t ffs_epfile_io(struct file *file,
 749                              char __user *buf, size_t len, int read)
 750 {
 751         struct ffs_epfile *epfile = file->private_data;
 752         struct ffs_ep *ep;
 753         char *data = NULL;
 754         ssize_t ret;
 755         int halt;
 756
 757         goto first_try;
 758         do {
 759                 spin_unlock_irq(&epfile->ffs->eps_lock);
 760                 mutex_unlock(&epfile->mutex);
 761
 762 first_try:
 763                 /* Are we still active? */
 764                 if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
 765                         ret = -ENODEV;
 766                         goto error;
 767                 }
 768
 769                 /* Wait for endpoint to be enabled */
 770                 ep = epfile->ep;
 771                 if (!ep) {
 772                         if (file->f_flags & O_NONBLOCK) {
 773                                 ret = -EAGAIN;
 774                                 goto error;
 775                         }
 776
 777                         if (wait_event_interruptible(epfile->wait,
 778                                                      (ep = epfile->ep))) {
 779                                 ret = -EINTR;
 780                                 goto error;
 781                         }
 782                 }
 783
 784                 /* Do we halt? */
 785                 halt = !read == !epfile->in;
 786                 if (halt && epfile->isoc) {
 787                         ret = -EINVAL;
 788                         goto error;
 789                 }
 790
 791                 /* Allocate & copy */
 792                 if (!halt && !data) {
 793                         data = kzalloc(len, GFP_KERNEL);
 794                         if (unlikely(!data))
 795                                 return -ENOMEM;
 796
 797                         if (!read &&
 798                             unlikely(__copy_from_user(data, buf, len))) {
 799                                 ret = -EFAULT;
 800                                 goto error;
 801                         }
 802                 }
 803
 804                 /* We will be using request */
 805                 ret = ffs_mutex_lock(&epfile->mutex,
 806                                      file->f_flags & O_NONBLOCK);
 807                 if (unlikely(ret))
 808                         goto error;
 809
 810                 /*
 811                  * We're called from user space, we can use _irq rather then
 812                  * _irqsave
 813                  */
 814                 spin_lock_irq(&epfile->ffs->eps_lock);
 815
 816                 /*
 817                  * While we were acquiring mutex endpoint got disabled
 818                  * or changed?
 819                  */
 820         } while (unlikely(epfile->ep != ep));
 821
 822         /* Halt */
 823         if (unlikely(halt)) {
 824                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 825                         usb_ep_set_halt(ep->ep);
 826                 spin_unlock_irq(&epfile->ffs->eps_lock);
 827                 ret = -EBADMSG;
 828         } else {
 829                 /* Fire the request */
 830                 DECLARE_COMPLETION_ONSTACK(done);
 831
 832                 struct usb_request *req = ep->req;
 833                 req->context  = &done;
 834                 req->complete = ffs_epfile_io_complete;
 835                 req->buf      = data;
 836                 req->length   = len;
 837
 838                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 839
 840                 spin_unlock_irq(&epfile->ffs->eps_lock);
 841
 842                 if (unlikely(ret < 0)) {
 843                         /* nop */
 844                 } else if (unlikely(wait_for_completion_interruptible(&done))) {
 845                         ret = -EINTR;
 846                         usb_ep_dequeue(ep->ep, req);
 847                 } else {
 848                         ret = ep->status;
 849                         if (read && ret > 0 &&
 850                             unlikely(copy_to_user(buf, data, ret)))
 851                                 ret = -EFAULT;
 852                 }
 853         }
 854
 855         mutex_unlock(&epfile->mutex);
 856 error:
 857         kfree(data);
 858         return ret;
 859 }
 860
 861 static ssize_t
 862 ffs_epfile_write(struct file *file, const char __user *buf, size_t len,
 863                  loff_t *ptr)
 864 {
 865         ENTER();
 866
 867         return ffs_epfile_io(file, (char __user *)buf, len, 0);
 868 }
 869
 870 static ssize_t
 871 ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr)
 872 {
 873         ENTER();
 874
 875         return ffs_epfile_io(file, buf, len, 1);
 876 }
 877
 878 static int
 879 ffs_epfile_open(struct inode *inode, struct file *file)
 880 {
 881         struct ffs_epfile *epfile = inode->i_private;
 882
 883         ENTER();
 884
 885         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 886                 return -ENODEV;
 887
 888         file->private_data = epfile;
 889         ffs_data_opened(epfile->ffs);
 890
 891         return 0;
 892 }
 893
 894 static int
 895 ffs_epfile_release(struct inode *inode, struct file *file)
 896 {
 897         struct ffs_epfile *epfile = inode->i_private;
 898
 899         ENTER();
 900
 901         ffs_data_closed(epfile->ffs);
 902
 903         return 0;
 904 }
 905
 906 static long ffs_epfile_ioctl(struct file *file, unsigned code,
 907                              unsigned long value)
 908 {
 909         struct ffs_epfile *epfile = file->private_data;
 910         int ret;
 911
 912         ENTER();
 913
 914         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 915                 return -ENODEV;
 916
 917         spin_lock_irq(&epfile->ffs->eps_lock);
 918         if (likely(epfile->ep)) {
 919                 switch (code) {
 920                 case FUNCTIONFS_FIFO_STATUS:
 921                         ret = usb_ep_fifo_status(epfile->ep->ep);
 922                         break;
 923                 case FUNCTIONFS_FIFO_FLUSH:
 924                         usb_ep_fifo_flush(epfile->ep->ep);
 925                         ret = 0;
 926                         break;
 927                 case FUNCTIONFS_CLEAR_HALT:
 928                         ret = usb_ep_clear_halt(epfile->ep->ep);
 929                         break;
 930                 case FUNCTIONFS_ENDPOINT_REVMAP:
 931                         ret = epfile->ep->num;
 932                         break;
 933                 default:
 934                         ret = -ENOTTY;
 935                 }
 936         } else {
 937                 ret = -ENODEV;
 938         }
 939         spin_unlock_irq(&epfile->ffs->eps_lock);
 940
 941         return ret;
 942 }
 943
 944 static const struct file_operations ffs_epfile_operations = {
 945         .owner =        THIS_MODULE,
 946         .llseek =       no_llseek,
 947
 948         .open =         ffs_epfile_open,
 949         .write =        ffs_epfile_write,
 950         .read =         ffs_epfile_read,
 951         .release =      ffs_epfile_release,
 952         .unlocked_ioctl =       ffs_epfile_ioctl,
 953 };
 954
 955
 956 /* File system and super block operations ***********************************/
 957
 958 /*
 959  * Mounting the file system creates a controller file, used first for
 960  * function configuration then later for event monitoring.
 961  */
 962
 963 static struct inode *__must_check
 964 ffs_sb_make_inode(struct super_block *sb, void *data,
 965                   const struct file_operations *fops,
 966                   const struct inode_operations *iops,
 967                   struct ffs_file_perms *perms)
 968 {
 969         struct inode *inode;
 970
 971         ENTER();
 972
 973         inode = new_inode(sb);
 974
 975         if (likely(inode)) {
 976                 struct timespec current_time = CURRENT_TIME;
 977
 978                 inode->i_ino     = get_next_ino();
 979                 inode->i_mode    = perms->mode;
 980                 inode->i_uid     = perms->uid;
 981                 inode->i_gid     = perms->gid;
 982                 inode->i_atime   = current_time;
 983                 inode->i_mtime   = current_time;
 984                 inode->i_ctime   = current_time;
 985                 inode->i_private = data;
 986                 if (fops)
 987                         inode->i_fop = fops;
 988                 if (iops)
 989                         inode->i_op  = iops;
 990         }
 991
 992         return inode;
 993 }
 994
 995 /* Create "regular" file */
 996 static struct inode *ffs_sb_create_file(struct super_block *sb,
 997                                         const char *name, void *data,
 998                                         const struct file_operations *fops,
 999                                         struct dentry **dentry_p)
1000 {
1001         struct ffs_data *ffs = sb->s_fs_info;
1002         struct dentry   *dentry;
1003         struct inode    *inode;
1004
1005         ENTER();
1006
1007         dentry = d_alloc_name(sb->s_root, name);
1008         if (unlikely(!dentry))
1009                 return NULL;
1010
1011         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1012         if (unlikely(!inode)) {
1013                 dput(dentry);
1014                 return NULL;
1015         }
1016
1017         d_add(dentry, inode);
1018         if (dentry_p)
1019                 *dentry_p = dentry;
1020
1021         return inode;
1022 }
1023
1024 /* Super block */
1025 static const struct super_operations ffs_sb_operations = {
1026         .statfs =       simple_statfs,
1027         .drop_inode =   generic_delete_inode,
1028 };
1029
1030 struct ffs_sb_fill_data {
1031         struct ffs_file_perms perms;
1032         umode_t root_mode;
1033         const char *dev_name;
1034 };
1035
1036 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1037 {
1038         struct ffs_sb_fill_data *data = _data;
1039         struct inode    *inode;
1040         struct dentry   *d;
1041         struct ffs_data *ffs;
1042
1043         ENTER();
1044
1045         /* Initialise data */
1046         ffs = ffs_data_new();
1047         if (unlikely(!ffs))
1048                 goto enomem0;
1049
1050         ffs->sb              = sb;
1051         ffs->dev_name        = data->dev_name;
1052         ffs->file_perms      = data->perms;
1053
1054         sb->s_fs_info        = ffs;
1055         sb->s_blocksize      = PAGE_CACHE_SIZE;
1056         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1057         sb->s_magic          = FUNCTIONFS_MAGIC;
1058         sb->s_op             = &ffs_sb_operations;
1059         sb->s_time_gran      = 1;
1060
1061         /* Root inode */
1062         data->perms.mode = data->root_mode;
1063         inode = ffs_sb_make_inode(sb, NULL,
1064                                   &simple_dir_operations,
1065                                   &simple_dir_inode_operations,
1066                                   &data->perms);
1067         if (unlikely(!inode))
1068                 goto enomem1;
1069         d = d_alloc_root(inode);
1070         if (unlikely(!d))
1071                 goto enomem2;
1072         sb->s_root = d;
1073
1074         /* EP0 file */
1075         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1076                                          &ffs_ep0_operations, NULL)))
1077                 goto enomem3;
1078
1079         return 0;
1080
1081 enomem3:
1082         dput(d);
1083 enomem2:
1084         iput(inode);
1085 enomem1:
1086         ffs_data_put(ffs);
1087 enomem0:
1088         return -ENOMEM;
1089 }
1090
1091 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1092 {
1093         ENTER();
1094
1095         if (!opts || !*opts)
1096                 return 0;
1097
1098         for (;;) {
1099                 char *end, *eq, *comma;
1100                 unsigned long value;
1101
1102                 /* Option limit */
1103                 comma = strchr(opts, ',');
1104                 if (comma)
1105                         *comma = 0;
1106
1107                 /* Value limit */
1108                 eq = strchr(opts, '=');
1109                 if (unlikely(!eq)) {
1110                         pr_err("'=' missing in %s\n", opts);
1111                         return -EINVAL;
1112                 }
1113                 *eq = 0;
1114
1115                 /* Parse value */
1116                 value = simple_strtoul(eq + 1, &end, 0);
1117                 if (unlikely(*end != ',' && *end != 0)) {
1118                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1119                         return -EINVAL;
1120                 }
1121
1122                 /* Interpret option */
1123                 switch (eq - opts) {
1124                 case 5:
1125                         if (!memcmp(opts, "rmode", 5))
1126                                 data->root_mode  = (value & 0555) | S_IFDIR;
1127                         else if (!memcmp(opts, "fmode", 5))
1128                                 data->perms.mode = (value & 0666) | S_IFREG;
1129                         else
1130                                 goto invalid;
1131                         break;
1132
1133                 case 4:
1134                         if (!memcmp(opts, "mode", 4)) {
1135                                 data->root_mode  = (value & 0555) | S_IFDIR;
1136                                 data->perms.mode = (value & 0666) | S_IFREG;
1137                         } else {
1138                                 goto invalid;
1139                         }
1140                         break;
1141
1142                 case 3:
1143                         if (!memcmp(opts, "uid", 3))
1144                                 data->perms.uid = value;
1145                         else if (!memcmp(opts, "gid", 3))
1146                                 data->perms.gid = value;
1147                         else
1148                                 goto invalid;
1149                         break;
1150
1151                 default:
1152 invalid:
1153                         pr_err("%s: invalid option\n", opts);
1154                         return -EINVAL;
1155                 }
1156
1157                 /* Next iteration */
1158                 if (!comma)
1159                         break;
1160                 opts = comma + 1;
1161         }
1162
1163         return 0;
1164 }
1165
1166 /* "mount -t functionfs dev_name /dev/function" ends up here */
1167
1168 static struct dentry *
1169 ffs_fs_mount(struct file_system_type *t, int flags,
1170               const char *dev_name, void *opts)
1171 {
1172         struct ffs_sb_fill_data data = {
1173                 .perms = {
1174                         .mode = S_IFREG | 0600,
1175                         .uid = 0,
1176                         .gid = 0
1177                 },
1178                 .root_mode = S_IFDIR | 0500,
1179         };
1180         int ret;
1181
1182         ENTER();
1183
1184         ret = functionfs_check_dev_callback(dev_name);
1185         if (unlikely(ret < 0))
1186                 return ERR_PTR(ret);
1187
1188         ret = ffs_fs_parse_opts(&data, opts);
1189         if (unlikely(ret < 0))
1190                 return ERR_PTR(ret);
1191
1192         data.dev_name = dev_name;
1193         return mount_single(t, flags, &data, ffs_sb_fill);
1194 }
1195
1196 static void
1197 ffs_fs_kill_sb(struct super_block *sb)
1198 {
1199         void *ptr;
1200
1201         ENTER();
1202
1203         kill_litter_super(sb);
1204         ptr = xchg(&sb->s_fs_info, NULL);
1205         if (ptr)
1206                 ffs_data_put(ptr);
1207 }
1208
1209 static struct file_system_type ffs_fs_type = {
1210         .owner          = THIS_MODULE,
1211         .name           = "functionfs",
1212         .mount          = ffs_fs_mount,
1213         .kill_sb        = ffs_fs_kill_sb,
1214 };
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(mutex_is_locked(&ffs->mutex) ||
1271                        spin_is_locked(&ffs->ev.waitq.lock) ||
1272                        waitqueue_active(&ffs->ev.waitq) ||
1273                        waitqueue_active(&ffs->ep0req_completion.wait));
1274                 kfree(ffs);
1275         }
1276 }
1277
1278 static void ffs_data_closed(struct ffs_data *ffs)
1279 {
1280         ENTER();
1281
1282         if (atomic_dec_and_test(&ffs->opened)) {
1283                 ffs->state = FFS_CLOSING;
1284                 ffs_data_reset(ffs);
1285         }
1286
1287         ffs_data_put(ffs);
1288 }
1289
1290 static struct ffs_data *ffs_data_new(void)
1291 {
1292         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1293         if (unlikely(!ffs))
1294                 return 0;
1295
1296         ENTER();
1297
1298         atomic_set(&ffs->ref, 1);
1299         atomic_set(&ffs->opened, 0);
1300         ffs->state = FFS_READ_DESCRIPTORS;
1301         mutex_init(&ffs->mutex);
1302         spin_lock_init(&ffs->eps_lock);
1303         init_waitqueue_head(&ffs->ev.waitq);
1304         init_completion(&ffs->ep0req_completion);
1305
1306         /* XXX REVISIT need to update it in some places, or do we? */
1307         ffs->ev.can_stall = 1;
1308
1309         return ffs;
1310 }
1311
1312 static void ffs_data_clear(struct ffs_data *ffs)
1313 {
1314         ENTER();
1315
1316         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags))
1317                 functionfs_closed_callback(ffs);
1318
1319         BUG_ON(ffs->gadget);
1320
1321         if (ffs->epfiles)
1322                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1323
1324         kfree(ffs->raw_descs);
1325         kfree(ffs->raw_strings);
1326         kfree(ffs->stringtabs);
1327 }
1328
1329 static void ffs_data_reset(struct ffs_data *ffs)
1330 {
1331         ENTER();
1332
1333         ffs_data_clear(ffs);
1334
1335         ffs->epfiles = NULL;
1336         ffs->raw_descs = NULL;
1337         ffs->raw_strings = NULL;
1338         ffs->stringtabs = NULL;
1339
1340         ffs->raw_descs_length = 0;
1341         ffs->raw_fs_descs_length = 0;
1342         ffs->fs_descs_count = 0;
1343         ffs->hs_descs_count = 0;
1344
1345         ffs->strings_count = 0;
1346         ffs->interfaces_count = 0;
1347         ffs->eps_count = 0;
1348
1349         ffs->ev.count = 0;
1350
1351         ffs->state = FFS_READ_DESCRIPTORS;
1352         ffs->setup_state = FFS_NO_SETUP;
1353         ffs->flags = 0;
1354 }
1355
1356
1357 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1358 {
1359         struct usb_gadget_strings **lang;
1360         int first_id;
1361
1362         ENTER();
1363
1364         if (WARN_ON(ffs->state != FFS_ACTIVE
1365                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1366                 return -EBADFD;
1367
1368         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1369         if (unlikely(first_id < 0))
1370                 return first_id;
1371
1372         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1373         if (unlikely(!ffs->ep0req))
1374                 return -ENOMEM;
1375         ffs->ep0req->complete = ffs_ep0_complete;
1376         ffs->ep0req->context = ffs;
1377
1378         lang = ffs->stringtabs;
1379         for (lang = ffs->stringtabs; *lang; ++lang) {
1380                 struct usb_string *str = (*lang)->strings;
1381                 int id = first_id;
1382                 for (; str->s; ++id, ++str)
1383                         str->id = id;
1384         }
1385
1386         ffs->gadget = cdev->gadget;
1387         ffs_data_get(ffs);
1388         return 0;
1389 }
1390
1391 static void functionfs_unbind(struct ffs_data *ffs)
1392 {
1393         ENTER();
1394
1395         if (!WARN_ON(!ffs->gadget)) {
1396                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1397                 ffs->ep0req = NULL;
1398                 ffs->gadget = NULL;
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 = kzalloc(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         ENTER();
1491
1492         ffs_data_put(func->ffs);
1493
1494         kfree(func->eps);
1495         /*
1496          * eps and interfaces_nums are allocated in the same chunk so
1497          * only one free is required.  Descriptors are also allocated
1498          * in the same chunk.
1499          */
1500
1501         kfree(func);
1502 }
1503
1504 static void ffs_func_eps_disable(struct ffs_function *func)
1505 {
1506         struct ffs_ep *ep         = func->eps;
1507         struct ffs_epfile *epfile = func->ffs->epfiles;
1508         unsigned count            = func->ffs->eps_count;
1509         unsigned long flags;
1510
1511         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1512         do {
1513                 /* pending requests get nuked */
1514                 if (likely(ep->ep))
1515                         usb_ep_disable(ep->ep);
1516                 epfile->ep = NULL;
1517
1518                 ++ep;
1519                 ++epfile;
1520         } while (--count);
1521         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1522 }
1523
1524 static int ffs_func_eps_enable(struct ffs_function *func)
1525 {
1526         struct ffs_data *ffs      = func->ffs;
1527         struct ffs_ep *ep         = func->eps;
1528         struct ffs_epfile *epfile = ffs->epfiles;
1529         unsigned count            = ffs->eps_count;
1530         unsigned long flags;
1531         int ret = 0;
1532
1533         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1534         do {
1535                 struct usb_endpoint_descriptor *ds;
1536                 ds = ep->descs[ep->descs[1] ? 1 : 0];
1537
1538                 ep->ep->driver_data = ep;
1539                 ep->ep->desc = ds;
1540                 ret = usb_ep_enable(ep->ep);
1541                 if (likely(!ret)) {
1542                         epfile->ep = ep;
1543                         epfile->in = usb_endpoint_dir_in(ds);
1544                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1545                 } else {
1546                         break;
1547                 }
1548
1549                 wake_up(&epfile->wait);
1550
1551                 ++ep;
1552                 ++epfile;
1553         } while (--count);
1554         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1555
1556         return ret;
1557 }
1558
1559
1560 /* Parsing and building descriptors and strings *****************************/
1561
1562 /*
1563  * This validates if data pointed by data is a valid USB descriptor as
1564  * well as record how many interfaces, endpoints and strings are
1565  * required by given configuration.  Returns address after the
1566  * descriptor or NULL if data is invalid.
1567  */
1568
1569 enum ffs_entity_type {
1570         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1571 };
1572
1573 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1574                                    u8 *valuep,
1575                                    struct usb_descriptor_header *desc,
1576                                    void *priv);
1577
1578 static int __must_check ffs_do_desc(char *data, unsigned len,
1579                                     ffs_entity_callback entity, void *priv)
1580 {
1581         struct usb_descriptor_header *_ds = (void *)data;
1582         u8 length;
1583         int ret;
1584
1585         ENTER();
1586
1587         /* At least two bytes are required: length and type */
1588         if (len < 2) {
1589                 pr_vdebug("descriptor too short\n");
1590                 return -EINVAL;
1591         }
1592
1593         /* If we have at least as many bytes as the descriptor takes? */
1594         length = _ds->bLength;
1595         if (len < length) {
1596                 pr_vdebug("descriptor longer then available data\n");
1597                 return -EINVAL;
1598         }
1599
1600 #define __entity_check_INTERFACE(val)  1
1601 #define __entity_check_STRING(val)     (val)
1602 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1603 #define __entity(type, val) do {                                        \
1604                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1605                 if (unlikely(!__entity_check_ ##type(val))) {           \
1606                         pr_vdebug("invalid entity's value\n");          \
1607                         return -EINVAL;                                 \
1608                 }                                                       \
1609                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1610                 if (unlikely(ret < 0)) {                                \
1611                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1612                                  (val), ret);                           \
1613                         return ret;                                     \
1614                 }                                                       \
1615         } while (0)
1616
1617         /* Parse descriptor depending on type. */
1618         switch (_ds->bDescriptorType) {
1619         case USB_DT_DEVICE:
1620         case USB_DT_CONFIG:
1621         case USB_DT_STRING:
1622         case USB_DT_DEVICE_QUALIFIER:
1623                 /* function can't have any of those */
1624                 pr_vdebug("descriptor reserved for gadget: %d\n",
1625                       _ds->bDescriptorType);
1626                 return -EINVAL;
1627
1628         case USB_DT_INTERFACE: {
1629                 struct usb_interface_descriptor *ds = (void *)_ds;
1630                 pr_vdebug("interface descriptor\n");
1631                 if (length != sizeof *ds)
1632                         goto inv_length;
1633
1634                 __entity(INTERFACE, ds->bInterfaceNumber);
1635                 if (ds->iInterface)
1636                         __entity(STRING, ds->iInterface);
1637         }
1638                 break;
1639
1640         case USB_DT_ENDPOINT: {
1641                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1642                 pr_vdebug("endpoint descriptor\n");
1643                 if (length != USB_DT_ENDPOINT_SIZE &&
1644                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1645                         goto inv_length;
1646                 __entity(ENDPOINT, ds->bEndpointAddress);
1647         }
1648                 break;
1649
1650         case USB_DT_OTG:
1651                 if (length != sizeof(struct usb_otg_descriptor))
1652                         goto inv_length;
1653                 break;
1654
1655         case USB_DT_INTERFACE_ASSOCIATION: {
1656                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1657                 pr_vdebug("interface association descriptor\n");
1658                 if (length != sizeof *ds)
1659                         goto inv_length;
1660                 if (ds->iFunction)
1661                         __entity(STRING, ds->iFunction);
1662         }
1663                 break;
1664
1665         case USB_DT_OTHER_SPEED_CONFIG:
1666         case USB_DT_INTERFACE_POWER:
1667         case USB_DT_DEBUG:
1668         case USB_DT_SECURITY:
1669         case USB_DT_CS_RADIO_CONTROL:
1670                 /* TODO */
1671                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1672                 return -EINVAL;
1673
1674         default:
1675                 /* We should never be here */
1676                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1677                 return -EINVAL;
1678
1679 inv_length:
1680                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1681                           _ds->bLength, _ds->bDescriptorType);
1682                 return -EINVAL;
1683         }
1684
1685 #undef __entity
1686 #undef __entity_check_DESCRIPTOR
1687 #undef __entity_check_INTERFACE
1688 #undef __entity_check_STRING
1689 #undef __entity_check_ENDPOINT
1690
1691         return length;
1692 }
1693
1694 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1695                                      ffs_entity_callback entity, void *priv)
1696 {
1697         const unsigned _len = len;
1698         unsigned long num = 0;
1699
1700         ENTER();
1701
1702         for (;;) {
1703                 int ret;
1704
1705                 if (num == count)
1706                         data = NULL;
1707
1708                 /* Record "descriptor" entity */
1709                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1710                 if (unlikely(ret < 0)) {
1711                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1712                                  num, ret);
1713                         return ret;
1714                 }
1715
1716                 if (!data)
1717                         return _len - len;
1718
1719                 ret = ffs_do_desc(data, len, entity, priv);
1720                 if (unlikely(ret < 0)) {
1721                         pr_debug("%s returns %d\n", __func__, ret);
1722                         return ret;
1723                 }
1724
1725                 len -= ret;
1726                 data += ret;
1727                 ++num;
1728         }
1729 }
1730
1731 static int __ffs_data_do_entity(enum ffs_entity_type type,
1732                                 u8 *valuep, struct usb_descriptor_header *desc,
1733                                 void *priv)
1734 {
1735         struct ffs_data *ffs = priv;
1736
1737         ENTER();
1738
1739         switch (type) {
1740         case FFS_DESCRIPTOR:
1741                 break;
1742
1743         case FFS_INTERFACE:
1744                 /*
1745                  * Interfaces are indexed from zero so if we
1746                  * encountered interface "n" then there are at least
1747                  * "n+1" interfaces.
1748                  */
1749                 if (*valuep >= ffs->interfaces_count)
1750                         ffs->interfaces_count = *valuep + 1;
1751                 break;
1752
1753         case FFS_STRING:
1754                 /*
1755                  * Strings are indexed from 1 (0 is magic ;) reserved
1756                  * for languages list or some such)
1757                  */
1758                 if (*valuep > ffs->strings_count)
1759                         ffs->strings_count = *valuep;
1760                 break;
1761
1762         case FFS_ENDPOINT:
1763                 /* Endpoints are indexed from 1 as well. */
1764                 if ((*valuep & USB_ENDPOINT_NUMBER_MASK) > ffs->eps_count)
1765                         ffs->eps_count = (*valuep & USB_ENDPOINT_NUMBER_MASK);
1766                 break;
1767         }
1768
1769         return 0;
1770 }
1771
1772 static int __ffs_data_got_descs(struct ffs_data *ffs,
1773                                 char *const _data, size_t len)
1774 {
1775         unsigned fs_count, hs_count;
1776         int fs_len, ret = -EINVAL;
1777         char *data = _data;
1778
1779         ENTER();
1780
1781         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_DESCRIPTORS_MAGIC ||
1782                      get_unaligned_le32(data + 4) != len))
1783                 goto error;
1784         fs_count = get_unaligned_le32(data +  8);
1785         hs_count = get_unaligned_le32(data + 12);
1786
1787         if (!fs_count && !hs_count)
1788                 goto einval;
1789
1790         data += 16;
1791         len  -= 16;
1792
1793         if (likely(fs_count)) {
1794                 fs_len = ffs_do_descs(fs_count, data, len,
1795                                       __ffs_data_do_entity, ffs);
1796                 if (unlikely(fs_len < 0)) {
1797                         ret = fs_len;
1798                         goto error;
1799                 }
1800
1801                 data += fs_len;
1802                 len  -= fs_len;
1803         } else {
1804                 fs_len = 0;
1805         }
1806
1807         if (likely(hs_count)) {
1808                 ret = ffs_do_descs(hs_count, data, len,
1809                                    __ffs_data_do_entity, ffs);
1810                 if (unlikely(ret < 0))
1811                         goto error;
1812         } else {
1813                 ret = 0;
1814         }
1815
1816         if (unlikely(len != ret))
1817                 goto einval;
1818
1819         ffs->raw_fs_descs_length = fs_len;
1820         ffs->raw_descs_length    = fs_len + ret;
1821         ffs->raw_descs           = _data;
1822         ffs->fs_descs_count      = fs_count;
1823         ffs->hs_descs_count      = hs_count;
1824
1825         return 0;
1826
1827 einval:
1828         ret = -EINVAL;
1829 error:
1830         kfree(_data);
1831         return ret;
1832 }
1833
1834 static int __ffs_data_got_strings(struct ffs_data *ffs,
1835                                   char *const _data, size_t len)
1836 {
1837         u32 str_count, needed_count, lang_count;
1838         struct usb_gadget_strings **stringtabs, *t;
1839         struct usb_string *strings, *s;
1840         const char *data = _data;
1841
1842         ENTER();
1843
1844         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
1845                      get_unaligned_le32(data + 4) != len))
1846                 goto error;
1847         str_count  = get_unaligned_le32(data + 8);
1848         lang_count = get_unaligned_le32(data + 12);
1849
1850         /* if one is zero the other must be zero */
1851         if (unlikely(!str_count != !lang_count))
1852                 goto error;
1853
1854         /* Do we have at least as many strings as descriptors need? */
1855         needed_count = ffs->strings_count;
1856         if (unlikely(str_count < needed_count))
1857                 goto error;
1858
1859         /*
1860          * If we don't need any strings just return and free all
1861          * memory.
1862          */
1863         if (!needed_count) {
1864                 kfree(_data);
1865                 return 0;
1866         }
1867
1868         /* Allocate everything in one chunk so there's less maintenance. */
1869         {
1870                 struct {
1871                         struct usb_gadget_strings *stringtabs[lang_count + 1];
1872                         struct usb_gadget_strings stringtab[lang_count];
1873                         struct usb_string strings[lang_count*(needed_count+1)];
1874                 } *d;
1875                 unsigned i = 0;
1876
1877                 d = kmalloc(sizeof *d, GFP_KERNEL);
1878                 if (unlikely(!d)) {
1879                         kfree(_data);
1880                         return -ENOMEM;
1881                 }
1882
1883                 stringtabs = d->stringtabs;
1884                 t = d->stringtab;
1885                 i = lang_count;
1886                 do {
1887                         *stringtabs++ = t++;
1888                 } while (--i);
1889                 *stringtabs = NULL;
1890
1891                 stringtabs = d->stringtabs;
1892                 t = d->stringtab;
1893                 s = d->strings;
1894                 strings = s;
1895         }
1896
1897         /* For each language */
1898         data += 16;
1899         len -= 16;
1900
1901         do { /* lang_count > 0 so we can use do-while */
1902                 unsigned needed = needed_count;
1903
1904                 if (unlikely(len < 3))
1905                         goto error_free;
1906                 t->language = get_unaligned_le16(data);
1907                 t->strings  = s;
1908                 ++t;
1909
1910                 data += 2;
1911                 len -= 2;
1912
1913                 /* For each string */
1914                 do { /* str_count > 0 so we can use do-while */
1915                         size_t length = strnlen(data, len);
1916
1917                         if (unlikely(length == len))
1918                                 goto error_free;
1919
1920                         /*
1921                          * User may provide more strings then we need,
1922                          * if that's the case we simply ignore the
1923                          * rest
1924                          */
1925                         if (likely(needed)) {
1926                                 /*
1927                                  * s->id will be set while adding
1928                                  * function to configuration so for
1929                                  * now just leave garbage here.
1930                                  */
1931                                 s->s = data;
1932                                 --needed;
1933                                 ++s;
1934                         }
1935
1936                         data += length + 1;
1937                         len -= length + 1;
1938                 } while (--str_count);
1939
1940                 s->id = 0;   /* terminator */
1941                 s->s = NULL;
1942                 ++s;
1943
1944         } while (--lang_count);
1945
1946         /* Some garbage left? */
1947         if (unlikely(len))
1948                 goto error_free;
1949
1950         /* Done! */
1951         ffs->stringtabs = stringtabs;
1952         ffs->raw_strings = _data;
1953
1954         return 0;
1955
1956 error_free:
1957         kfree(stringtabs);
1958 error:
1959         kfree(_data);
1960         return -EINVAL;
1961 }
1962
1963
1964 /* Events handling and management *******************************************/
1965
1966 static void __ffs_event_add(struct ffs_data *ffs,
1967                             enum usb_functionfs_event_type type)
1968 {
1969         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
1970         int neg = 0;
1971
1972         /*
1973          * Abort any unhandled setup
1974          *
1975          * We do not need to worry about some cmpxchg() changing value
1976          * of ffs->setup_state without holding the lock because when
1977          * state is FFS_SETUP_PENDING cmpxchg() in several places in
1978          * the source does nothing.
1979          */
1980         if (ffs->setup_state == FFS_SETUP_PENDING)
1981                 ffs->setup_state = FFS_SETUP_CANCELED;
1982
1983         switch (type) {
1984         case FUNCTIONFS_RESUME:
1985                 rem_type2 = FUNCTIONFS_SUSPEND;
1986                 /* FALL THROUGH */
1987         case FUNCTIONFS_SUSPEND:
1988         case FUNCTIONFS_SETUP:
1989                 rem_type1 = type;
1990                 /* Discard all similar events */
1991                 break;
1992
1993         case FUNCTIONFS_BIND:
1994         case FUNCTIONFS_UNBIND:
1995         case FUNCTIONFS_DISABLE:
1996         case FUNCTIONFS_ENABLE:
1997                 /* Discard everything other then power management. */
1998                 rem_type1 = FUNCTIONFS_SUSPEND;
1999                 rem_type2 = FUNCTIONFS_RESUME;
2000                 neg = 1;
2001                 break;
2002
2003         default:
2004                 BUG();
2005         }
2006
2007         {
2008                 u8 *ev  = ffs->ev.types, *out = ev;
2009                 unsigned n = ffs->ev.count;
2010                 for (; n; --n, ++ev)
2011                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2012                                 *out++ = *ev;
2013                         else
2014                                 pr_vdebug("purging event %d\n", *ev);
2015                 ffs->ev.count = out - ffs->ev.types;
2016         }
2017
2018         pr_vdebug("adding event %d\n", type);
2019         ffs->ev.types[ffs->ev.count++] = type;
2020         wake_up_locked(&ffs->ev.waitq);
2021 }
2022
2023 static void ffs_event_add(struct ffs_data *ffs,
2024                           enum usb_functionfs_event_type type)
2025 {
2026         unsigned long flags;
2027         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2028         __ffs_event_add(ffs, type);
2029         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2030 }
2031
2032
2033 /* Bind/unbind USB function hooks *******************************************/
2034
2035 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2036                                     struct usb_descriptor_header *desc,
2037                                     void *priv)
2038 {
2039         struct usb_endpoint_descriptor *ds = (void *)desc;
2040         struct ffs_function *func = priv;
2041         struct ffs_ep *ffs_ep;
2042
2043         /*
2044          * If hs_descriptors is not NULL then we are reading hs
2045          * descriptors now
2046          */
2047         const int isHS = func->function.hs_descriptors != NULL;
2048         unsigned idx;
2049
2050         if (type != FFS_DESCRIPTOR)
2051                 return 0;
2052
2053         if (isHS)
2054                 func->function.hs_descriptors[(long)valuep] = desc;
2055         else
2056                 func->function.descriptors[(long)valuep]    = desc;
2057
2058         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2059                 return 0;
2060
2061         idx = (ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK) - 1;
2062         ffs_ep = func->eps + idx;
2063
2064         if (unlikely(ffs_ep->descs[isHS])) {
2065                 pr_vdebug("two %sspeed descriptors for EP %d\n",
2066                           isHS ? "high" : "full",
2067                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2068                 return -EINVAL;
2069         }
2070         ffs_ep->descs[isHS] = ds;
2071
2072         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2073         if (ffs_ep->ep) {
2074                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2075                 if (!ds->wMaxPacketSize)
2076                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2077         } else {
2078                 struct usb_request *req;
2079                 struct usb_ep *ep;
2080
2081                 pr_vdebug("autoconfig\n");
2082                 ep = usb_ep_autoconfig(func->gadget, ds);
2083                 if (unlikely(!ep))
2084                         return -ENOTSUPP;
2085                 ep->driver_data = func->eps + idx;
2086
2087                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2088                 if (unlikely(!req))
2089                         return -ENOMEM;
2090
2091                 ffs_ep->ep  = ep;
2092                 ffs_ep->req = req;
2093                 func->eps_revmap[ds->bEndpointAddress &
2094                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2095         }
2096         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2097
2098         return 0;
2099 }
2100
2101 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2102                                    struct usb_descriptor_header *desc,
2103                                    void *priv)
2104 {
2105         struct ffs_function *func = priv;
2106         unsigned idx;
2107         u8 newValue;
2108
2109         switch (type) {
2110         default:
2111         case FFS_DESCRIPTOR:
2112                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2113                 return 0;
2114
2115         case FFS_INTERFACE:
2116                 idx = *valuep;
2117                 if (func->interfaces_nums[idx] < 0) {
2118                         int id = usb_interface_id(func->conf, &func->function);
2119                         if (unlikely(id < 0))
2120                                 return id;
2121                         func->interfaces_nums[idx] = id;
2122                 }
2123                 newValue = func->interfaces_nums[idx];
2124                 break;
2125
2126         case FFS_STRING:
2127                 /* String' IDs are allocated when fsf_data is bound to cdev */
2128                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2129                 break;
2130
2131         case FFS_ENDPOINT:
2132                 /*
2133                  * USB_DT_ENDPOINT are handled in
2134                  * __ffs_func_bind_do_descs().
2135                  */
2136                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2137                         return 0;
2138
2139                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2140                 if (unlikely(!func->eps[idx].ep))
2141                         return -EINVAL;
2142
2143                 {
2144                         struct usb_endpoint_descriptor **descs;
2145                         descs = func->eps[idx].descs;
2146                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2147                 }
2148                 break;
2149         }
2150
2151         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2152         *valuep = newValue;
2153         return 0;
2154 }
2155
2156 static int ffs_func_bind(struct usb_configuration *c,
2157                          struct usb_function *f)
2158 {
2159         struct ffs_function *func = ffs_func_from_usb(f);
2160         struct ffs_data *ffs = func->ffs;
2161
2162         const int full = !!func->ffs->fs_descs_count;
2163         const int high = gadget_is_dualspeed(func->gadget) &&
2164                 func->ffs->hs_descs_count;
2165
2166         int ret;
2167
2168         /* Make it a single chunk, less management later on */
2169         struct {
2170                 struct ffs_ep eps[ffs->eps_count];
2171                 struct usb_descriptor_header
2172                         *fs_descs[full ? ffs->fs_descs_count + 1 : 0];
2173                 struct usb_descriptor_header
2174                         *hs_descs[high ? ffs->hs_descs_count + 1 : 0];
2175                 short inums[ffs->interfaces_count];
2176                 char raw_descs[high ? ffs->raw_descs_length
2177                                     : ffs->raw_fs_descs_length];
2178         } *data;
2179
2180         ENTER();
2181
2182         /* Only high speed but not supported by gadget? */
2183         if (unlikely(!(full | high)))
2184                 return -ENOTSUPP;
2185
2186         /* Allocate */
2187         data = kmalloc(sizeof *data, GFP_KERNEL);
2188         if (unlikely(!data))
2189                 return -ENOMEM;
2190
2191         /* Zero */
2192         memset(data->eps, 0, sizeof data->eps);
2193         memcpy(data->raw_descs, ffs->raw_descs + 16, sizeof data->raw_descs);
2194         memset(data->inums, 0xff, sizeof data->inums);
2195         for (ret = ffs->eps_count; ret; --ret)
2196                 data->eps[ret].num = -1;
2197
2198         /* Save pointers */
2199         func->eps             = data->eps;
2200         func->interfaces_nums = data->inums;
2201
2202         /*
2203          * Go through all the endpoint descriptors and allocate
2204          * endpoints first, so that later we can rewrite the endpoint
2205          * numbers without worrying that it may be described later on.
2206          */
2207         if (likely(full)) {
2208                 func->function.descriptors = data->fs_descs;
2209                 ret = ffs_do_descs(ffs->fs_descs_count,
2210                                    data->raw_descs,
2211                                    sizeof data->raw_descs,
2212                                    __ffs_func_bind_do_descs, func);
2213                 if (unlikely(ret < 0))
2214                         goto error;
2215         } else {
2216                 ret = 0;
2217         }
2218
2219         if (likely(high)) {
2220                 func->function.hs_descriptors = data->hs_descs;
2221                 ret = ffs_do_descs(ffs->hs_descs_count,
2222                                    data->raw_descs + ret,
2223                                    (sizeof data->raw_descs) - ret,
2224                                    __ffs_func_bind_do_descs, func);
2225         }
2226
2227         /*
2228          * Now handle interface numbers allocation and interface and
2229          * endpoint numbers rewriting.  We can do that in one go
2230          * now.
2231          */
2232         ret = ffs_do_descs(ffs->fs_descs_count +
2233                            (high ? ffs->hs_descs_count : 0),
2234                            data->raw_descs, sizeof data->raw_descs,
2235                            __ffs_func_bind_do_nums, func);
2236         if (unlikely(ret < 0))
2237                 goto error;
2238
2239         /* And we're done */
2240         ffs_event_add(ffs, FUNCTIONFS_BIND);
2241         return 0;
2242
2243 error:
2244         /* XXX Do we need to release all claimed endpoints here? */
2245         return ret;
2246 }
2247
2248
2249 /* Other USB function hooks *************************************************/
2250
2251 static void ffs_func_unbind(struct usb_configuration *c,
2252                             struct usb_function *f)
2253 {
2254         struct ffs_function *func = ffs_func_from_usb(f);
2255         struct ffs_data *ffs = func->ffs;
2256
2257         ENTER();
2258
2259         if (ffs->func == func) {
2260                 ffs_func_eps_disable(func);
2261                 ffs->func = NULL;
2262         }
2263
2264         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
2265
2266         ffs_func_free(func);
2267 }
2268
2269 static int ffs_func_set_alt(struct usb_function *f,
2270                             unsigned interface, unsigned alt)
2271 {
2272         struct ffs_function *func = ffs_func_from_usb(f);
2273         struct ffs_data *ffs = func->ffs;
2274         int ret = 0, intf;
2275
2276         if (alt != (unsigned)-1) {
2277                 intf = ffs_func_revmap_intf(func, interface);
2278                 if (unlikely(intf < 0))
2279                         return intf;
2280         }
2281
2282         if (ffs->func)
2283                 ffs_func_eps_disable(ffs->func);
2284
2285         if (ffs->state != FFS_ACTIVE)
2286                 return -ENODEV;
2287
2288         if (alt == (unsigned)-1) {
2289                 ffs->func = NULL;
2290                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2291                 return 0;
2292         }
2293
2294         ffs->func = func;
2295         ret = ffs_func_eps_enable(func);
2296         if (likely(ret >= 0))
2297                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2298         return ret;
2299 }
2300
2301 static void ffs_func_disable(struct usb_function *f)
2302 {
2303         ffs_func_set_alt(f, 0, (unsigned)-1);
2304 }
2305
2306 static int ffs_func_setup(struct usb_function *f,
2307                           const struct usb_ctrlrequest *creq)
2308 {
2309         struct ffs_function *func = ffs_func_from_usb(f);
2310         struct ffs_data *ffs = func->ffs;
2311         unsigned long flags;
2312         int ret;
2313
2314         ENTER();
2315
2316         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2317         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2318         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2319         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
2320         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
2321
2322         /*
2323          * Most requests directed to interface go through here
2324          * (notable exceptions are set/get interface) so we need to
2325          * handle them.  All other either handled by composite or
2326          * passed to usb_configuration->setup() (if one is set).  No
2327          * matter, we will handle requests directed to endpoint here
2328          * as well (as it's straightforward) but what to do with any
2329          * other request?
2330          */
2331         if (ffs->state != FFS_ACTIVE)
2332                 return -ENODEV;
2333
2334         switch (creq->bRequestType & USB_RECIP_MASK) {
2335         case USB_RECIP_INTERFACE:
2336                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
2337                 if (unlikely(ret < 0))
2338                         return ret;
2339                 break;
2340
2341         case USB_RECIP_ENDPOINT:
2342                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
2343                 if (unlikely(ret < 0))
2344                         return ret;
2345                 break;
2346
2347         default:
2348                 return -EOPNOTSUPP;
2349         }
2350
2351         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2352         ffs->ev.setup = *creq;
2353         ffs->ev.setup.wIndex = cpu_to_le16(ret);
2354         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
2355         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2356
2357         return 0;
2358 }
2359
2360 static void ffs_func_suspend(struct usb_function *f)
2361 {
2362         ENTER();
2363         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
2364 }
2365
2366 static void ffs_func_resume(struct usb_function *f)
2367 {
2368         ENTER();
2369         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
2370 }
2371
2372
2373 /* Endpoint and interface numbers reverse mapping ***************************/
2374
2375 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
2376 {
2377         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
2378         return num ? num : -EDOM;
2379 }
2380
2381 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
2382 {
2383         short *nums = func->interfaces_nums;
2384         unsigned count = func->ffs->interfaces_count;
2385
2386         for (; count; --count, ++nums) {
2387                 if (*nums >= 0 && *nums == intf)
2388                         return nums - func->interfaces_nums;
2389         }
2390
2391         return -EDOM;
2392 }
2393
2394
2395 /* Misc helper functions ****************************************************/
2396
2397 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
2398 {
2399         return nonblock
2400                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
2401                 : mutex_lock_interruptible(mutex);
2402 }
2403
2404 static char *ffs_prepare_buffer(const char * __user buf, size_t len)
2405 {
2406         char *data;
2407
2408         if (unlikely(!len))
2409                 return NULL;
2410
2411         data = kmalloc(len, GFP_KERNEL);
2412         if (unlikely(!data))
2413                 return ERR_PTR(-ENOMEM);
2414
2415         if (unlikely(__copy_from_user(data, buf, len))) {
2416                 kfree(data);
2417                 return ERR_PTR(-EFAULT);
2418         }
2419
2420         pr_vdebug("Buffer from user space:\n");
2421         ffs_dump_mem("", data, len);
2422
2423         return data;
2424 }