drivers/usb/gadget/function/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 <linux/module.h>
  26 #include <linux/uio.h>
  27 #include <asm/unaligned.h>
  28
  29 #include <linux/usb/composite.h>
  30 #include <linux/usb/functionfs.h>
  31
  32 #include <linux/aio.h>
  33 #include <linux/mmu_context.h>
  34 #include <linux/poll.h>
  35 #include <linux/eventfd.h>
  36
  37 #include "u_fs.h"
  38 #include "u_f.h"
  39 #include "u_os_desc.h"
  40 #include "configfs.h"
  41
  42 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  43
  44 /* Reference counter handling */
  45 static void ffs_data_get(struct ffs_data *ffs);
  46 static void ffs_data_put(struct ffs_data *ffs);
  47 /* Creates new ffs_data object. */
  48 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
  49
  50 /* Opened counter handling. */
  51 static void ffs_data_opened(struct ffs_data *ffs);
  52 static void ffs_data_closed(struct ffs_data *ffs);
  53
  54 /* Called with ffs->mutex held; take over ownership of data. */
  55 static int __must_check
  56 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  57 static int __must_check
  58 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  59
  60
  61 /* The function structure ***************************************************/
  62
  63 struct ffs_ep;
  64
  65 struct ffs_function {
  66         struct usb_configuration        *conf;
  67         struct usb_gadget               *gadget;
  68         struct ffs_data                 *ffs;
  69
  70         struct ffs_ep                   *eps;
  71         u8                              eps_revmap[16];
  72         short                           *interfaces_nums;
  73
  74         struct usb_function             function;
  75 };
  76
  77
  78 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  79 {
  80         return container_of(f, struct ffs_function, function);
  81 }
  82
  83
  84 static inline enum ffs_setup_state
  85 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  86 {
  87         return (enum ffs_setup_state)
  88                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  89 }
  90
  91
  92 static void ffs_func_eps_disable(struct ffs_function *func);
  93 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  94
  95 static int ffs_func_bind(struct usb_configuration *,
  96                          struct usb_function *);
  97 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
  98 static void ffs_func_disable(struct usb_function *);
  99 static int ffs_func_setup(struct usb_function *,
 100                           const struct usb_ctrlrequest *);
 101 static void ffs_func_suspend(struct usb_function *);
 102 static void ffs_func_resume(struct usb_function *);
 103
 104
 105 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 106 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 107
 108
 109 /* The endpoints structures *************************************************/
 110
 111 struct ffs_ep {
 112         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 113         struct usb_request              *req;   /* P: epfile->mutex */
 114
 115         /* [0]: full speed, [1]: high speed, [2]: super speed */
 116         struct usb_endpoint_descriptor  *descs[3];
 117
 118         u8                              num;
 119
 120         int                             status; /* P: epfile->mutex */
 121 };
 122
 123 struct ffs_epfile {
 124         /* Protects ep->ep and ep->req. */
 125         struct mutex                    mutex;
 126         wait_queue_head_t               wait;
 127
 128         struct ffs_data                 *ffs;
 129         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 130
 131         struct dentry                   *dentry;
 132
 133         char                            name[5];
 134
 135         unsigned char                   in;     /* P: ffs->eps_lock */
 136         unsigned char                   isoc;   /* P: ffs->eps_lock */
 137
 138         unsigned char                   _pad;
 139 };
 140
 141 /*  ffs_io_data structure ***************************************************/
 142
 143 struct ffs_io_data {
 144         bool aio;
 145         bool read;
 146
 147         struct kiocb *kiocb;
 148         struct iov_iter data;
 149         const void *to_free;
 150         char *buf;
 151
 152         struct mm_struct *mm;
 153         struct work_struct work;
 154
 155         struct usb_ep *ep;
 156         struct usb_request *req;
 157
 158         struct ffs_data *ffs;
 159 };
 160
 161 struct ffs_desc_helper {
 162         struct ffs_data *ffs;
 163         unsigned interfaces_count;
 164         unsigned eps_count;
 165 };
 166
 167 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 168 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 169
 170 static struct dentry *
 171 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 172                    const struct file_operations *fops);
 173
 174 /* Devices management *******************************************************/
 175
 176 DEFINE_MUTEX(ffs_lock);
 177 EXPORT_SYMBOL_GPL(ffs_lock);
 178
 179 static struct ffs_dev *_ffs_find_dev(const char *name);
 180 static struct ffs_dev *_ffs_alloc_dev(void);
 181 static int _ffs_name_dev(struct ffs_dev *dev, const char *name);
 182 static void _ffs_free_dev(struct ffs_dev *dev);
 183 static void *ffs_acquire_dev(const char *dev_name);
 184 static void ffs_release_dev(struct ffs_data *ffs_data);
 185 static int ffs_ready(struct ffs_data *ffs);
 186 static void ffs_closed(struct ffs_data *ffs);
 187
 188 /* Misc helper functions ****************************************************/
 189
 190 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 191         __attribute__((warn_unused_result, nonnull));
 192 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 193         __attribute__((warn_unused_result, nonnull));
 194
 195
 196 /* Control file aka ep0 *****************************************************/
 197
 198 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 199 {
 200         struct ffs_data *ffs = req->context;
 201
 202         complete_all(&ffs->ep0req_completion);
 203 }
 204
 205 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 206 {
 207         struct usb_request *req = ffs->ep0req;
 208         int ret;
 209
 210         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 211
 212         spin_unlock_irq(&ffs->ev.waitq.lock);
 213
 214         req->buf      = data;
 215         req->length   = len;
 216
 217         /*
 218          * UDC layer requires to provide a buffer even for ZLP, but should
 219          * not use it at all. Let's provide some poisoned pointer to catch
 220          * possible bug in the driver.
 221          */
 222         if (req->buf == NULL)
 223                 req->buf = (void *)0xDEADBABE;
 224
 225         reinit_completion(&ffs->ep0req_completion);
 226
 227         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 228         if (unlikely(ret < 0))
 229                 return ret;
 230
 231         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 232         if (unlikely(ret)) {
 233                 usb_ep_dequeue(ffs->gadget->ep0, req);
 234                 return -EINTR;
 235         }
 236
 237         ffs->setup_state = FFS_NO_SETUP;
 238         return req->status ? req->status : req->actual;
 239 }
 240
 241 static int __ffs_ep0_stall(struct ffs_data *ffs)
 242 {
 243         if (ffs->ev.can_stall) {
 244                 pr_vdebug("ep0 stall\n");
 245                 usb_ep_set_halt(ffs->gadget->ep0);
 246                 ffs->setup_state = FFS_NO_SETUP;
 247                 return -EL2HLT;
 248         } else {
 249                 pr_debug("bogus ep0 stall!\n");
 250                 return -ESRCH;
 251         }
 252 }
 253
 254 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 255                              size_t len, loff_t *ptr)
 256 {
 257         struct ffs_data *ffs = file->private_data;
 258         ssize_t ret;
 259         char *data;
 260
 261         ENTER();
 262
 263         /* Fast check if setup was canceled */
 264         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 265                 return -EIDRM;
 266
 267         /* Acquire mutex */
 268         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 269         if (unlikely(ret < 0))
 270                 return ret;
 271
 272         /* Check state */
 273         switch (ffs->state) {
 274         case FFS_READ_DESCRIPTORS:
 275         case FFS_READ_STRINGS:
 276                 /* Copy data */
 277                 if (unlikely(len < 16)) {
 278                         ret = -EINVAL;
 279                         break;
 280                 }
 281
 282                 data = ffs_prepare_buffer(buf, len);
 283                 if (IS_ERR(data)) {
 284                         ret = PTR_ERR(data);
 285                         break;
 286                 }
 287
 288                 /* Handle data */
 289                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 290                         pr_info("read descriptors\n");
 291                         ret = __ffs_data_got_descs(ffs, data, len);
 292                         if (unlikely(ret < 0))
 293                                 break;
 294
 295                         ffs->state = FFS_READ_STRINGS;
 296                         ret = len;
 297                 } else {
 298                         pr_info("read strings\n");
 299                         ret = __ffs_data_got_strings(ffs, data, len);
 300                         if (unlikely(ret < 0))
 301                                 break;
 302
 303                         ret = ffs_epfiles_create(ffs);
 304                         if (unlikely(ret)) {
 305                                 ffs->state = FFS_CLOSING;
 306                                 break;
 307                         }
 308
 309                         ffs->state = FFS_ACTIVE;
 310                         mutex_unlock(&ffs->mutex);
 311
 312                         ret = ffs_ready(ffs);
 313                         if (unlikely(ret < 0)) {
 314                                 ffs->state = FFS_CLOSING;
 315                                 return ret;
 316                         }
 317
 318                         return len;
 319                 }
 320                 break;
 321
 322         case FFS_ACTIVE:
 323                 data = NULL;
 324                 /*
 325                  * We're called from user space, we can use _irq
 326                  * rather then _irqsave
 327                  */
 328                 spin_lock_irq(&ffs->ev.waitq.lock);
 329                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 330                 case FFS_SETUP_CANCELLED:
 331                         ret = -EIDRM;
 332                         goto done_spin;
 333
 334                 case FFS_NO_SETUP:
 335                         ret = -ESRCH;
 336                         goto done_spin;
 337
 338                 case FFS_SETUP_PENDING:
 339                         break;
 340                 }
 341
 342                 /* FFS_SETUP_PENDING */
 343                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 344                         spin_unlock_irq(&ffs->ev.waitq.lock);
 345                         ret = __ffs_ep0_stall(ffs);
 346                         break;
 347                 }
 348
 349                 /* FFS_SETUP_PENDING and not stall */
 350                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 351
 352                 spin_unlock_irq(&ffs->ev.waitq.lock);
 353
 354                 data = ffs_prepare_buffer(buf, len);
 355                 if (IS_ERR(data)) {
 356                         ret = PTR_ERR(data);
 357                         break;
 358                 }
 359
 360                 spin_lock_irq(&ffs->ev.waitq.lock);
 361
 362                 /*
 363                  * We are guaranteed to be still in FFS_ACTIVE state
 364                  * but the state of setup could have changed from
 365                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 366                  * to check for that.  If that happened we copied data
 367                  * from user space in vain but it's unlikely.
 368                  *
 369                  * For sure we are not in FFS_NO_SETUP since this is
 370                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 371                  * transition can be performed and it's protected by
 372                  * mutex.
 373                  */
 374                 if (ffs_setup_state_clear_cancelled(ffs) ==
 375                     FFS_SETUP_CANCELLED) {
 376                         ret = -EIDRM;
 377 done_spin:
 378                         spin_unlock_irq(&ffs->ev.waitq.lock);
 379                 } else {
 380                         /* unlocks spinlock */
 381                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 382                 }
 383                 kfree(data);
 384                 break;
 385
 386         default:
 387                 ret = -EBADFD;
 388                 break;
 389         }
 390
 391         mutex_unlock(&ffs->mutex);
 392         return ret;
 393 }
 394
 395 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 396 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 397                                      size_t n)
 398 {
 399         /*
 400          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 401          * size of ffs->ev.types array (which is four) so that's how much space
 402          * we reserve.
 403          */
 404         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 405         const size_t size = n * sizeof *events;
 406         unsigned i = 0;
 407
 408         memset(events, 0, size);
 409
 410         do {
 411                 events[i].type = ffs->ev.types[i];
 412                 if (events[i].type == FUNCTIONFS_SETUP) {
 413                         events[i].u.setup = ffs->ev.setup;
 414                         ffs->setup_state = FFS_SETUP_PENDING;
 415                 }
 416         } while (++i < n);
 417
 418         ffs->ev.count -= n;
 419         if (ffs->ev.count)
 420                 memmove(ffs->ev.types, ffs->ev.types + n,
 421                         ffs->ev.count * sizeof *ffs->ev.types);
 422
 423         spin_unlock_irq(&ffs->ev.waitq.lock);
 424         mutex_unlock(&ffs->mutex);
 425
 426         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 427 }
 428
 429 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 430                             size_t len, loff_t *ptr)
 431 {
 432         struct ffs_data *ffs = file->private_data;
 433         char *data = NULL;
 434         size_t n;
 435         int ret;
 436
 437         ENTER();
 438
 439         /* Fast check if setup was canceled */
 440         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 441                 return -EIDRM;
 442
 443         /* Acquire mutex */
 444         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 445         if (unlikely(ret < 0))
 446                 return ret;
 447
 448         /* Check state */
 449         if (ffs->state != FFS_ACTIVE) {
 450                 ret = -EBADFD;
 451                 goto done_mutex;
 452         }
 453
 454         /*
 455          * We're called from user space, we can use _irq rather then
 456          * _irqsave
 457          */
 458         spin_lock_irq(&ffs->ev.waitq.lock);
 459
 460         switch (ffs_setup_state_clear_cancelled(ffs)) {
 461         case FFS_SETUP_CANCELLED:
 462                 ret = -EIDRM;
 463                 break;
 464
 465         case FFS_NO_SETUP:
 466                 n = len / sizeof(struct usb_functionfs_event);
 467                 if (unlikely(!n)) {
 468                         ret = -EINVAL;
 469                         break;
 470                 }
 471
 472                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 473                         ret = -EAGAIN;
 474                         break;
 475                 }
 476
 477                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 478                                                         ffs->ev.count)) {
 479                         ret = -EINTR;
 480                         break;
 481                 }
 482
 483                 return __ffs_ep0_read_events(ffs, buf,
 484                                              min(n, (size_t)ffs->ev.count));
 485
 486         case FFS_SETUP_PENDING:
 487                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 488                         spin_unlock_irq(&ffs->ev.waitq.lock);
 489                         ret = __ffs_ep0_stall(ffs);
 490                         goto done_mutex;
 491                 }
 492
 493                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 494
 495                 spin_unlock_irq(&ffs->ev.waitq.lock);
 496
 497                 if (likely(len)) {
 498                         data = kmalloc(len, GFP_KERNEL);
 499                         if (unlikely(!data)) {
 500                                 ret = -ENOMEM;
 501                                 goto done_mutex;
 502                         }
 503                 }
 504
 505                 spin_lock_irq(&ffs->ev.waitq.lock);
 506
 507                 /* See ffs_ep0_write() */
 508                 if (ffs_setup_state_clear_cancelled(ffs) ==
 509                     FFS_SETUP_CANCELLED) {
 510                         ret = -EIDRM;
 511                         break;
 512                 }
 513
 514                 /* unlocks spinlock */
 515                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 516                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 517                         ret = -EFAULT;
 518                 goto done_mutex;
 519
 520         default:
 521                 ret = -EBADFD;
 522                 break;
 523         }
 524
 525         spin_unlock_irq(&ffs->ev.waitq.lock);
 526 done_mutex:
 527         mutex_unlock(&ffs->mutex);
 528         kfree(data);
 529         return ret;
 530 }
 531
 532 static int ffs_ep0_open(struct inode *inode, struct file *file)
 533 {
 534         struct ffs_data *ffs = inode->i_private;
 535
 536         ENTER();
 537
 538         if (unlikely(ffs->state == FFS_CLOSING))
 539                 return -EBUSY;
 540
 541         file->private_data = ffs;
 542         ffs_data_opened(ffs);
 543
 544         return 0;
 545 }
 546
 547 static int ffs_ep0_release(struct inode *inode, struct file *file)
 548 {
 549         struct ffs_data *ffs = file->private_data;
 550
 551         ENTER();
 552
 553         ffs_data_closed(ffs);
 554
 555         return 0;
 556 }
 557
 558 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 559 {
 560         struct ffs_data *ffs = file->private_data;
 561         struct usb_gadget *gadget = ffs->gadget;
 562         long ret;
 563
 564         ENTER();
 565
 566         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 567                 struct ffs_function *func = ffs->func;
 568                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 569         } else if (gadget && gadget->ops->ioctl) {
 570                 ret = gadget->ops->ioctl(gadget, code, value);
 571         } else {
 572                 ret = -ENOTTY;
 573         }
 574
 575         return ret;
 576 }
 577
 578 static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
 579 {
 580         struct ffs_data *ffs = file->private_data;
 581         unsigned int mask = POLLWRNORM;
 582         int ret;
 583
 584         poll_wait(file, &ffs->ev.waitq, wait);
 585
 586         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 587         if (unlikely(ret < 0))
 588                 return mask;
 589
 590         switch (ffs->state) {
 591         case FFS_READ_DESCRIPTORS:
 592         case FFS_READ_STRINGS:
 593                 mask |= POLLOUT;
 594                 break;
 595
 596         case FFS_ACTIVE:
 597                 switch (ffs->setup_state) {
 598                 case FFS_NO_SETUP:
 599                         if (ffs->ev.count)
 600                                 mask |= POLLIN;
 601                         break;
 602
 603                 case FFS_SETUP_PENDING:
 604                 case FFS_SETUP_CANCELLED:
 605                         mask |= (POLLIN | POLLOUT);
 606                         break;
 607                 }
 608         case FFS_CLOSING:
 609                 break;
 610         case FFS_DEACTIVATED:
 611                 break;
 612         }
 613
 614         mutex_unlock(&ffs->mutex);
 615
 616         return mask;
 617 }
 618
 619 static const struct file_operations ffs_ep0_operations = {
 620         .llseek =       no_llseek,
 621
 622         .open =         ffs_ep0_open,
 623         .write =        ffs_ep0_write,
 624         .read =         ffs_ep0_read,
 625         .release =      ffs_ep0_release,
 626         .unlocked_ioctl =       ffs_ep0_ioctl,
 627         .poll =         ffs_ep0_poll,
 628 };
 629
 630
 631 /* "Normal" endpoints operations ********************************************/
 632
 633 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 634 {
 635         ENTER();
 636         if (likely(req->context)) {
 637                 struct ffs_ep *ep = _ep->driver_data;
 638                 ep->status = req->status ? req->status : req->actual;
 639                 complete(req->context);
 640         }
 641 }
 642
 643 static void ffs_user_copy_worker(struct work_struct *work)
 644 {
 645         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 646                                                    work);
 647         int ret = io_data->req->status ? io_data->req->status :
 648                                          io_data->req->actual;
 649         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 650
 651         if (io_data->read && ret > 0) {
 652                 mm_segment_t oldfs = get_fs();
 653
 654                 set_fs(USER_DS);
 655                 use_mm(io_data->mm);
 656                 ret = copy_to_iter(io_data->buf, ret, &io_data->data);
 657                 if (ret != io_data->req->actual && iov_iter_count(&io_data->data))
 658                         ret = -EFAULT;
 659                 unuse_mm(io_data->mm);
 660                 set_fs(oldfs);
 661         }
 662
 663         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 664
 665         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 666                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 667
 668         usb_ep_free_request(io_data->ep, io_data->req);
 669
 670         if (io_data->read)
 671                 kfree(io_data->to_free);
 672         kfree(io_data->buf);
 673         kfree(io_data);
 674 }
 675
 676 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 677                                          struct usb_request *req)
 678 {
 679         struct ffs_io_data *io_data = req->context;
 680
 681         ENTER();
 682
 683         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 684         schedule_work(&io_data->work);
 685 }
 686
 687 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 688 {
 689         struct ffs_epfile *epfile = file->private_data;
 690         struct ffs_ep *ep;
 691         char *data = NULL;
 692         ssize_t ret, data_len = -EINVAL;
 693         int halt;
 694
 695         /* Are we still active? */
 696         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
 697                 ret = -ENODEV;
 698                 goto error;
 699         }
 700
 701         /* Wait for endpoint to be enabled */
 702         ep = epfile->ep;
 703         if (!ep) {
 704                 if (file->f_flags & O_NONBLOCK) {
 705                         ret = -EAGAIN;
 706                         goto error;
 707                 }
 708
 709                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
 710                 if (ret) {
 711                         ret = -EINTR;
 712                         goto error;
 713                 }
 714         }
 715
 716         /* Do we halt? */
 717         halt = (!io_data->read == !epfile->in);
 718         if (halt && epfile->isoc) {
 719                 ret = -EINVAL;
 720                 goto error;
 721         }
 722
 723         /* Allocate & copy */
 724         if (!halt) {
 725                 /*
 726                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 727                  * before the waiting completes, so do not assign to 'gadget' earlier
 728                  */
 729                 struct usb_gadget *gadget = epfile->ffs->gadget;
 730                 size_t copied;
 731
 732                 spin_lock_irq(&epfile->ffs->eps_lock);
 733                 /* In the meantime, endpoint got disabled or changed. */
 734                 if (epfile->ep != ep) {
 735                         spin_unlock_irq(&epfile->ffs->eps_lock);
 736                         return -ESHUTDOWN;
 737                 }
 738                 data_len = iov_iter_count(&io_data->data);
 739                 /*
 740                  * Controller may require buffer size to be aligned to
 741                  * maxpacketsize of an out endpoint.
 742                  */
 743                 if (io_data->read)
 744                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
 745                 spin_unlock_irq(&epfile->ffs->eps_lock);
 746
 747                 data = kmalloc(data_len, GFP_KERNEL);
 748                 if (unlikely(!data))
 749                         return -ENOMEM;
 750                 if (!io_data->read) {
 751                         copied = copy_from_iter(data, data_len, &io_data->data);
 752                         if (copied != data_len) {
 753                                 ret = -EFAULT;
 754                                 goto error;
 755                         }
 756                 }
 757         }
 758
 759         /* We will be using request */
 760         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 761         if (unlikely(ret))
 762                 goto error;
 763
 764         spin_lock_irq(&epfile->ffs->eps_lock);
 765
 766         if (epfile->ep != ep) {
 767                 /* In the meantime, endpoint got disabled or changed. */
 768                 ret = -ESHUTDOWN;
 769                 spin_unlock_irq(&epfile->ffs->eps_lock);
 770         } else if (halt) {
 771                 /* Halt */
 772                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 773                         usb_ep_set_halt(ep->ep);
 774                 spin_unlock_irq(&epfile->ffs->eps_lock);
 775                 ret = -EBADMSG;
 776         } else {
 777                 /* Fire the request */
 778                 struct usb_request *req;
 779
 780                 /*
 781                  * Sanity Check: even though data_len can't be used
 782                  * uninitialized at the time I write this comment, some
 783                  * compilers complain about this situation.
 784                  * In order to keep the code clean from warnings, data_len is
 785                  * being initialized to -EINVAL during its declaration, which
 786                  * means we can't rely on compiler anymore to warn no future
 787                  * changes won't result in data_len being used uninitialized.
 788                  * For such reason, we're adding this redundant sanity check
 789                  * here.
 790                  */
 791                 if (unlikely(data_len == -EINVAL)) {
 792                         WARN(1, "%s: data_len == -EINVAL\n", __func__);
 793                         ret = -EINVAL;
 794                         goto error_lock;
 795                 }
 796
 797                 if (io_data->aio) {
 798                         req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC);
 799                         if (unlikely(!req))
 800                                 goto error_lock;
 801
 802                         req->buf      = data;
 803                         req->length   = data_len;
 804
 805                         io_data->buf = data;
 806                         io_data->ep = ep->ep;
 807                         io_data->req = req;
 808                         io_data->ffs = epfile->ffs;
 809
 810                         req->context  = io_data;
 811                         req->complete = ffs_epfile_async_io_complete;
 812
 813                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 814                         if (unlikely(ret)) {
 815                                 usb_ep_free_request(ep->ep, req);
 816                                 goto error_lock;
 817                         }
 818                         ret = -EIOCBQUEUED;
 819
 820                         spin_unlock_irq(&epfile->ffs->eps_lock);
 821                 } else {
 822                         DECLARE_COMPLETION_ONSTACK(done);
 823
 824                         req = ep->req;
 825                         req->buf      = data;
 826                         req->length   = data_len;
 827
 828                         req->context  = &done;
 829                         req->complete = ffs_epfile_io_complete;
 830
 831                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 832
 833                         spin_unlock_irq(&epfile->ffs->eps_lock);
 834
 835                         if (unlikely(ret < 0)) {
 836                                 /* nop */
 837                         } else if (unlikely(
 838                                    wait_for_completion_interruptible(&done))) {
 839                                 ret = -EINTR;
 840                                 usb_ep_dequeue(ep->ep, req);
 841                         } else {
 842                                 /*
 843                                  * XXX We may end up silently droping data
 844                                  * here.  Since data_len (i.e. req->length) may
 845                                  * be bigger than len (after being rounded up
 846                                  * to maxpacketsize), we may end up with more
 847                                  * data then user space has space for.
 848                                  */
 849                                 ret = ep->status;
 850                                 if (io_data->read && ret > 0) {
 851                                         ret = copy_to_iter(data, ret, &io_data->data);
 852                                         if (!ret)
 853                                                 ret = -EFAULT;
 854                                 }
 855                         }
 856                         kfree(data);
 857                 }
 858         }
 859
 860         mutex_unlock(&epfile->mutex);
 861         return ret;
 862
 863 error_lock:
 864         spin_unlock_irq(&epfile->ffs->eps_lock);
 865         mutex_unlock(&epfile->mutex);
 866 error:
 867         kfree(data);
 868         return ret;
 869 }
 870
 871 static int
 872 ffs_epfile_open(struct inode *inode, struct file *file)
 873 {
 874         struct ffs_epfile *epfile = inode->i_private;
 875
 876         ENTER();
 877
 878         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 879                 return -ENODEV;
 880
 881         file->private_data = epfile;
 882         ffs_data_opened(epfile->ffs);
 883
 884         return 0;
 885 }
 886
 887 static int ffs_aio_cancel(struct kiocb *kiocb)
 888 {
 889         struct ffs_io_data *io_data = kiocb->private;
 890         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
 891         int value;
 892
 893         ENTER();
 894
 895         spin_lock_irq(&epfile->ffs->eps_lock);
 896
 897         if (likely(io_data && io_data->ep && io_data->req))
 898                 value = usb_ep_dequeue(io_data->ep, io_data->req);
 899         else
 900                 value = -EINVAL;
 901
 902         spin_unlock_irq(&epfile->ffs->eps_lock);
 903
 904         return value;
 905 }
 906
 907 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
 908 {
 909         struct ffs_io_data io_data, *p = &io_data;
 910         ssize_t res;
 911
 912         ENTER();
 913
 914         if (!is_sync_kiocb(kiocb)) {
 915                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
 916                 if (unlikely(!p))
 917                         return -ENOMEM;
 918                 p->aio = true;
 919         } else {
 920                 p->aio = false;
 921         }
 922
 923         p->read = false;
 924         p->kiocb = kiocb;
 925         p->data = *from;
 926         p->mm = current->mm;
 927
 928         kiocb->private = p;
 929
 930         if (p->aio)
 931                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 932
 933         res = ffs_epfile_io(kiocb->ki_filp, p);
 934         if (res == -EIOCBQUEUED)
 935                 return res;
 936         if (p->aio)
 937                 kfree(p);
 938         else
 939                 *from = p->data;
 940         return res;
 941 }
 942
 943 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
 944 {
 945         struct ffs_io_data io_data, *p = &io_data;
 946         ssize_t res;
 947
 948         ENTER();
 949
 950         if (!is_sync_kiocb(kiocb)) {
 951                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
 952                 if (unlikely(!p))
 953                         return -ENOMEM;
 954                 p->aio = true;
 955         } else {
 956                 p->aio = false;
 957         }
 958
 959         p->read = true;
 960         p->kiocb = kiocb;
 961         if (p->aio) {
 962                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
 963                 if (!p->to_free) {
 964                         kfree(p);
 965                         return -ENOMEM;
 966                 }
 967         } else {
 968                 p->data = *to;
 969                 p->to_free = NULL;
 970         }
 971         p->mm = current->mm;
 972
 973         kiocb->private = p;
 974
 975         if (p->aio)
 976                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 977
 978         res = ffs_epfile_io(kiocb->ki_filp, p);
 979         if (res == -EIOCBQUEUED)
 980                 return res;
 981
 982         if (p->aio) {
 983                 kfree(p->to_free);
 984                 kfree(p);
 985         } else {
 986                 *to = p->data;
 987         }
 988         return res;
 989 }
 990
 991 static int
 992 ffs_epfile_release(struct inode *inode, struct file *file)
 993 {
 994         struct ffs_epfile *epfile = inode->i_private;
 995
 996         ENTER();
 997
 998         ffs_data_closed(epfile->ffs);
 999
1000         return 0;
1001 }
1002
1003 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1004                              unsigned long value)
1005 {
1006         struct ffs_epfile *epfile = file->private_data;
1007         int ret;
1008
1009         ENTER();
1010
1011         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1012                 return -ENODEV;
1013
1014         spin_lock_irq(&epfile->ffs->eps_lock);
1015         if (likely(epfile->ep)) {
1016                 switch (code) {
1017                 case FUNCTIONFS_FIFO_STATUS:
1018                         ret = usb_ep_fifo_status(epfile->ep->ep);
1019                         break;
1020                 case FUNCTIONFS_FIFO_FLUSH:
1021                         usb_ep_fifo_flush(epfile->ep->ep);
1022                         ret = 0;
1023                         break;
1024                 case FUNCTIONFS_CLEAR_HALT:
1025                         ret = usb_ep_clear_halt(epfile->ep->ep);
1026                         break;
1027                 case FUNCTIONFS_ENDPOINT_REVMAP:
1028                         ret = epfile->ep->num;
1029                         break;
1030                 case FUNCTIONFS_ENDPOINT_DESC:
1031                 {
1032                         int desc_idx;
1033                         struct usb_endpoint_descriptor *desc;
1034
1035                         switch (epfile->ffs->gadget->speed) {
1036                         case USB_SPEED_SUPER:
1037                                 desc_idx = 2;
1038                                 break;
1039                         case USB_SPEED_HIGH:
1040                                 desc_idx = 1;
1041                                 break;
1042                         default:
1043                                 desc_idx = 0;
1044                         }
1045                         desc = epfile->ep->descs[desc_idx];
1046
1047                         spin_unlock_irq(&epfile->ffs->eps_lock);
1048                         ret = copy_to_user((void *)value, desc, sizeof(*desc));
1049                         if (ret)
1050                                 ret = -EFAULT;
1051                         return ret;
1052                 }
1053                 default:
1054                         ret = -ENOTTY;
1055                 }
1056         } else {
1057                 ret = -ENODEV;
1058         }
1059         spin_unlock_irq(&epfile->ffs->eps_lock);
1060
1061         return ret;
1062 }
1063
1064 static const struct file_operations ffs_epfile_operations = {
1065         .llseek =       no_llseek,
1066
1067         .open =         ffs_epfile_open,
1068         .write_iter =   ffs_epfile_write_iter,
1069         .read_iter =    ffs_epfile_read_iter,
1070         .release =      ffs_epfile_release,
1071         .unlocked_ioctl =       ffs_epfile_ioctl,
1072 };
1073
1074
1075 /* File system and super block operations ***********************************/
1076
1077 /*
1078  * Mounting the file system creates a controller file, used first for
1079  * function configuration then later for event monitoring.
1080  */
1081
1082 static struct inode *__must_check
1083 ffs_sb_make_inode(struct super_block *sb, void *data,
1084                   const struct file_operations *fops,
1085                   const struct inode_operations *iops,
1086                   struct ffs_file_perms *perms)
1087 {
1088         struct inode *inode;
1089
1090         ENTER();
1091
1092         inode = new_inode(sb);
1093
1094         if (likely(inode)) {
1095                 struct timespec current_time = CURRENT_TIME;
1096
1097                 inode->i_ino     = get_next_ino();
1098                 inode->i_mode    = perms->mode;
1099                 inode->i_uid     = perms->uid;
1100                 inode->i_gid     = perms->gid;
1101                 inode->i_atime   = current_time;
1102                 inode->i_mtime   = current_time;
1103                 inode->i_ctime   = current_time;
1104                 inode->i_private = data;
1105                 if (fops)
1106                         inode->i_fop = fops;
1107                 if (iops)
1108                         inode->i_op  = iops;
1109         }
1110
1111         return inode;
1112 }
1113
1114 /* Create "regular" file */
1115 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1116                                         const char *name, void *data,
1117                                         const struct file_operations *fops)
1118 {
1119         struct ffs_data *ffs = sb->s_fs_info;
1120         struct dentry   *dentry;
1121         struct inode    *inode;
1122
1123         ENTER();
1124
1125         dentry = d_alloc_name(sb->s_root, name);
1126         if (unlikely(!dentry))
1127                 return NULL;
1128
1129         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1130         if (unlikely(!inode)) {
1131                 dput(dentry);
1132                 return NULL;
1133         }
1134
1135         d_add(dentry, inode);
1136         return dentry;
1137 }
1138
1139 /* Super block */
1140 static const struct super_operations ffs_sb_operations = {
1141         .statfs =       simple_statfs,
1142         .drop_inode =   generic_delete_inode,
1143 };
1144
1145 struct ffs_sb_fill_data {
1146         struct ffs_file_perms perms;
1147         umode_t root_mode;
1148         const char *dev_name;
1149         bool no_disconnect;
1150         struct ffs_data *ffs_data;
1151 };
1152
1153 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1154 {
1155         struct ffs_sb_fill_data *data = _data;
1156         struct inode    *inode;
1157         struct ffs_data *ffs = data->ffs_data;
1158
1159         ENTER();
1160
1161         ffs->sb              = sb;
1162         data->ffs_data       = NULL;
1163         sb->s_fs_info        = ffs;
1164         sb->s_blocksize      = PAGE_CACHE_SIZE;
1165         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1166         sb->s_magic          = FUNCTIONFS_MAGIC;
1167         sb->s_op             = &ffs_sb_operations;
1168         sb->s_time_gran      = 1;
1169
1170         /* Root inode */
1171         data->perms.mode = data->root_mode;
1172         inode = ffs_sb_make_inode(sb, NULL,
1173                                   &simple_dir_operations,
1174                                   &simple_dir_inode_operations,
1175                                   &data->perms);
1176         sb->s_root = d_make_root(inode);
1177         if (unlikely(!sb->s_root))
1178                 return -ENOMEM;
1179
1180         /* EP0 file */
1181         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1182                                          &ffs_ep0_operations)))
1183                 return -ENOMEM;
1184
1185         return 0;
1186 }
1187
1188 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1189 {
1190         ENTER();
1191
1192         if (!opts || !*opts)
1193                 return 0;
1194
1195         for (;;) {
1196                 unsigned long value;
1197                 char *eq, *comma;
1198
1199                 /* Option limit */
1200                 comma = strchr(opts, ',');
1201                 if (comma)
1202                         *comma = 0;
1203
1204                 /* Value limit */
1205                 eq = strchr(opts, '=');
1206                 if (unlikely(!eq)) {
1207                         pr_err("'=' missing in %s\n", opts);
1208                         return -EINVAL;
1209                 }
1210                 *eq = 0;
1211
1212                 /* Parse value */
1213                 if (kstrtoul(eq + 1, 0, &value)) {
1214                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1215                         return -EINVAL;
1216                 }
1217
1218                 /* Interpret option */
1219                 switch (eq - opts) {
1220                 case 13:
1221                         if (!memcmp(opts, "no_disconnect", 13))
1222                                 data->no_disconnect = !!value;
1223                         else
1224                                 goto invalid;
1225                         break;
1226                 case 5:
1227                         if (!memcmp(opts, "rmode", 5))
1228                                 data->root_mode  = (value & 0555) | S_IFDIR;
1229                         else if (!memcmp(opts, "fmode", 5))
1230                                 data->perms.mode = (value & 0666) | S_IFREG;
1231                         else
1232                                 goto invalid;
1233                         break;
1234
1235                 case 4:
1236                         if (!memcmp(opts, "mode", 4)) {
1237                                 data->root_mode  = (value & 0555) | S_IFDIR;
1238                                 data->perms.mode = (value & 0666) | S_IFREG;
1239                         } else {
1240                                 goto invalid;
1241                         }
1242                         break;
1243
1244                 case 3:
1245                         if (!memcmp(opts, "uid", 3)) {
1246                                 data->perms.uid = make_kuid(current_user_ns(), value);
1247                                 if (!uid_valid(data->perms.uid)) {
1248                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1249                                         return -EINVAL;
1250                                 }
1251                         } else if (!memcmp(opts, "gid", 3)) {
1252                                 data->perms.gid = make_kgid(current_user_ns(), value);
1253                                 if (!gid_valid(data->perms.gid)) {
1254                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1255                                         return -EINVAL;
1256                                 }
1257                         } else {
1258                                 goto invalid;
1259                         }
1260                         break;
1261
1262                 default:
1263 invalid:
1264                         pr_err("%s: invalid option\n", opts);
1265                         return -EINVAL;
1266                 }
1267
1268                 /* Next iteration */
1269                 if (!comma)
1270                         break;
1271                 opts = comma + 1;
1272         }
1273
1274         return 0;
1275 }
1276
1277 /* "mount -t functionfs dev_name /dev/function" ends up here */
1278
1279 static struct dentry *
1280 ffs_fs_mount(struct file_system_type *t, int flags,
1281               const char *dev_name, void *opts)
1282 {
1283         struct ffs_sb_fill_data data = {
1284                 .perms = {
1285                         .mode = S_IFREG | 0600,
1286                         .uid = GLOBAL_ROOT_UID,
1287                         .gid = GLOBAL_ROOT_GID,
1288                 },
1289                 .root_mode = S_IFDIR | 0500,
1290                 .no_disconnect = false,
1291         };
1292         struct dentry *rv;
1293         int ret;
1294         void *ffs_dev;
1295         struct ffs_data *ffs;
1296
1297         ENTER();
1298
1299         ret = ffs_fs_parse_opts(&data, opts);
1300         if (unlikely(ret < 0))
1301                 return ERR_PTR(ret);
1302
1303         ffs = ffs_data_new();
1304         if (unlikely(!ffs))
1305                 return ERR_PTR(-ENOMEM);
1306         ffs->file_perms = data.perms;
1307         ffs->no_disconnect = data.no_disconnect;
1308
1309         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1310         if (unlikely(!ffs->dev_name)) {
1311                 ffs_data_put(ffs);
1312                 return ERR_PTR(-ENOMEM);
1313         }
1314
1315         ffs_dev = ffs_acquire_dev(dev_name);
1316         if (IS_ERR(ffs_dev)) {
1317                 ffs_data_put(ffs);
1318                 return ERR_CAST(ffs_dev);
1319         }
1320         ffs->private_data = ffs_dev;
1321         data.ffs_data = ffs;
1322
1323         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1324         if (IS_ERR(rv) && data.ffs_data) {
1325                 ffs_release_dev(data.ffs_data);
1326                 ffs_data_put(data.ffs_data);
1327         }
1328         return rv;
1329 }
1330
1331 static void
1332 ffs_fs_kill_sb(struct super_block *sb)
1333 {
1334         ENTER();
1335
1336         kill_litter_super(sb);
1337         if (sb->s_fs_info) {
1338                 ffs_release_dev(sb->s_fs_info);
1339                 ffs_data_closed(sb->s_fs_info);
1340         }
1341 }
1342
1343 static struct file_system_type ffs_fs_type = {
1344         .owner          = THIS_MODULE,
1345         .name           = "functionfs",
1346         .mount          = ffs_fs_mount,
1347         .kill_sb        = ffs_fs_kill_sb,
1348 };
1349 MODULE_ALIAS_FS("functionfs");
1350
1351
1352 /* Driver's main init/cleanup functions *************************************/
1353
1354 static int functionfs_init(void)
1355 {
1356         int ret;
1357
1358         ENTER();
1359
1360         ret = register_filesystem(&ffs_fs_type);
1361         if (likely(!ret))
1362                 pr_info("file system registered\n");
1363         else
1364                 pr_err("failed registering file system (%d)\n", ret);
1365
1366         return ret;
1367 }
1368
1369 static void functionfs_cleanup(void)
1370 {
1371         ENTER();
1372
1373         pr_info("unloading\n");
1374         unregister_filesystem(&ffs_fs_type);
1375 }
1376
1377
1378 /* ffs_data and ffs_function construction and destruction code **************/
1379
1380 static void ffs_data_clear(struct ffs_data *ffs);
1381 static void ffs_data_reset(struct ffs_data *ffs);
1382
1383 static void ffs_data_get(struct ffs_data *ffs)
1384 {
1385         ENTER();
1386
1387         atomic_inc(&ffs->ref);
1388 }
1389
1390 static void ffs_data_opened(struct ffs_data *ffs)
1391 {
1392         ENTER();
1393
1394         atomic_inc(&ffs->ref);
1395         if (atomic_add_return(1, &ffs->opened) == 1 &&
1396                         ffs->state == FFS_DEACTIVATED) {
1397                 ffs->state = FFS_CLOSING;
1398                 ffs_data_reset(ffs);
1399         }
1400 }
1401
1402 static void ffs_data_put(struct ffs_data *ffs)
1403 {
1404         ENTER();
1405
1406         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1407                 pr_info("%s(): freeing\n", __func__);
1408                 ffs_data_clear(ffs);
1409                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1410                        waitqueue_active(&ffs->ep0req_completion.wait));
1411                 kfree(ffs->dev_name);
1412                 kfree(ffs);
1413         }
1414 }
1415
1416 static void ffs_data_closed(struct ffs_data *ffs)
1417 {
1418         ENTER();
1419
1420         if (atomic_dec_and_test(&ffs->opened)) {
1421                 if (ffs->no_disconnect) {
1422                         ffs->state = FFS_DEACTIVATED;
1423                         if (ffs->epfiles) {
1424                                 ffs_epfiles_destroy(ffs->epfiles,
1425                                                    ffs->eps_count);
1426                                 ffs->epfiles = NULL;
1427                         }
1428                         if (ffs->setup_state == FFS_SETUP_PENDING)
1429                                 __ffs_ep0_stall(ffs);
1430                 } else {
1431                         ffs->state = FFS_CLOSING;
1432                         ffs_data_reset(ffs);
1433                 }
1434         }
1435         if (atomic_read(&ffs->opened) < 0) {
1436                 ffs->state = FFS_CLOSING;
1437                 ffs_data_reset(ffs);
1438         }
1439
1440         ffs_data_put(ffs);
1441 }
1442
1443 static struct ffs_data *ffs_data_new(void)
1444 {
1445         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1446         if (unlikely(!ffs))
1447                 return NULL;
1448
1449         ENTER();
1450
1451         atomic_set(&ffs->ref, 1);
1452         atomic_set(&ffs->opened, 0);
1453         ffs->state = FFS_READ_DESCRIPTORS;
1454         mutex_init(&ffs->mutex);
1455         spin_lock_init(&ffs->eps_lock);
1456         init_waitqueue_head(&ffs->ev.waitq);
1457         init_completion(&ffs->ep0req_completion);
1458
1459         /* XXX REVISIT need to update it in some places, or do we? */
1460         ffs->ev.can_stall = 1;
1461
1462         return ffs;
1463 }
1464
1465 static void ffs_data_clear(struct ffs_data *ffs)
1466 {
1467         ENTER();
1468
1469         ffs_closed(ffs);
1470
1471         BUG_ON(ffs->gadget);
1472
1473         if (ffs->epfiles)
1474                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1475
1476         if (ffs->ffs_eventfd)
1477                 eventfd_ctx_put(ffs->ffs_eventfd);
1478
1479         kfree(ffs->raw_descs_data);
1480         kfree(ffs->raw_strings);
1481         kfree(ffs->stringtabs);
1482 }
1483
1484 static void ffs_data_reset(struct ffs_data *ffs)
1485 {
1486         ENTER();
1487
1488         ffs_data_clear(ffs);
1489
1490         ffs->epfiles = NULL;
1491         ffs->raw_descs_data = NULL;
1492         ffs->raw_descs = NULL;
1493         ffs->raw_strings = NULL;
1494         ffs->stringtabs = NULL;
1495
1496         ffs->raw_descs_length = 0;
1497         ffs->fs_descs_count = 0;
1498         ffs->hs_descs_count = 0;
1499         ffs->ss_descs_count = 0;
1500
1501         ffs->strings_count = 0;
1502         ffs->interfaces_count = 0;
1503         ffs->eps_count = 0;
1504
1505         ffs->ev.count = 0;
1506
1507         ffs->state = FFS_READ_DESCRIPTORS;
1508         ffs->setup_state = FFS_NO_SETUP;
1509         ffs->flags = 0;
1510 }
1511
1512
1513 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1514 {
1515         struct usb_gadget_strings **lang;
1516         int first_id;
1517
1518         ENTER();
1519
1520         if (WARN_ON(ffs->state != FFS_ACTIVE
1521                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1522                 return -EBADFD;
1523
1524         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1525         if (unlikely(first_id < 0))
1526                 return first_id;
1527
1528         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1529         if (unlikely(!ffs->ep0req))
1530                 return -ENOMEM;
1531         ffs->ep0req->complete = ffs_ep0_complete;
1532         ffs->ep0req->context = ffs;
1533
1534         lang = ffs->stringtabs;
1535         if (lang) {
1536                 for (; *lang; ++lang) {
1537                         struct usb_string *str = (*lang)->strings;
1538                         int id = first_id;
1539                         for (; str->s; ++id, ++str)
1540                                 str->id = id;
1541                 }
1542         }
1543
1544         ffs->gadget = cdev->gadget;
1545         ffs_data_get(ffs);
1546         return 0;
1547 }
1548
1549 static void functionfs_unbind(struct ffs_data *ffs)
1550 {
1551         ENTER();
1552
1553         if (!WARN_ON(!ffs->gadget)) {
1554                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1555                 ffs->ep0req = NULL;
1556                 ffs->gadget = NULL;
1557                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1558                 ffs_data_put(ffs);
1559         }
1560 }
1561
1562 static int ffs_epfiles_create(struct ffs_data *ffs)
1563 {
1564         struct ffs_epfile *epfile, *epfiles;
1565         unsigned i, count;
1566
1567         ENTER();
1568
1569         count = ffs->eps_count;
1570         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1571         if (!epfiles)
1572                 return -ENOMEM;
1573
1574         epfile = epfiles;
1575         for (i = 1; i <= count; ++i, ++epfile) {
1576                 epfile->ffs = ffs;
1577                 mutex_init(&epfile->mutex);
1578                 init_waitqueue_head(&epfile->wait);
1579                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1580                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1581                 else
1582                         sprintf(epfile->name, "ep%u", i);
1583                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1584                                                  epfile,
1585                                                  &ffs_epfile_operations);
1586                 if (unlikely(!epfile->dentry)) {
1587                         ffs_epfiles_destroy(epfiles, i - 1);
1588                         return -ENOMEM;
1589                 }
1590         }
1591
1592         ffs->epfiles = epfiles;
1593         return 0;
1594 }
1595
1596 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1597 {
1598         struct ffs_epfile *epfile = epfiles;
1599
1600         ENTER();
1601
1602         for (; count; --count, ++epfile) {
1603                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1604                        waitqueue_active(&epfile->wait));
1605                 if (epfile->dentry) {
1606                         d_delete(epfile->dentry);
1607                         dput(epfile->dentry);
1608                         epfile->dentry = NULL;
1609                 }
1610         }
1611
1612         kfree(epfiles);
1613 }
1614
1615 static void ffs_func_eps_disable(struct ffs_function *func)
1616 {
1617         struct ffs_ep *ep         = func->eps;
1618         struct ffs_epfile *epfile = func->ffs->epfiles;
1619         unsigned count            = func->ffs->eps_count;
1620         unsigned long flags;
1621
1622         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1623         do {
1624                 /* pending requests get nuked */
1625                 if (likely(ep->ep))
1626                         usb_ep_disable(ep->ep);
1627                 ++ep;
1628
1629                 if (epfile) {
1630                         epfile->ep = NULL;
1631                         ++epfile;
1632                 }
1633         } while (--count);
1634         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1635 }
1636
1637 static int ffs_func_eps_enable(struct ffs_function *func)
1638 {
1639         struct ffs_data *ffs      = func->ffs;
1640         struct ffs_ep *ep         = func->eps;
1641         struct ffs_epfile *epfile = ffs->epfiles;
1642         unsigned count            = ffs->eps_count;
1643         unsigned long flags;
1644         int ret = 0;
1645
1646         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1647         do {
1648                 struct usb_endpoint_descriptor *ds;
1649                 struct usb_ss_ep_comp_descriptor *comp_desc = NULL;
1650                 int needs_comp_desc = false;
1651                 int desc_idx;
1652
1653                 if (ffs->gadget->speed == USB_SPEED_SUPER) {
1654                         desc_idx = 2;
1655                         needs_comp_desc = true;
1656                 } else if (ffs->gadget->speed == USB_SPEED_HIGH)
1657                         desc_idx = 1;
1658                 else
1659                         desc_idx = 0;
1660
1661                 /* fall-back to lower speed if desc missing for current speed */
1662                 do {
1663                         ds = ep->descs[desc_idx];
1664                 } while (!ds && --desc_idx >= 0);
1665
1666                 if (!ds) {
1667                         ret = -EINVAL;
1668                         break;
1669                 }
1670
1671                 ep->ep->driver_data = ep;
1672                 ep->ep->desc = ds;
1673
1674                 if (needs_comp_desc) {
1675                         comp_desc = (struct usb_ss_ep_comp_descriptor *)(ds +
1676                                         USB_DT_ENDPOINT_SIZE);
1677                         ep->ep->maxburst = comp_desc->bMaxBurst + 1;
1678                         ep->ep->comp_desc = comp_desc;
1679                 }
1680
1681                 ret = usb_ep_enable(ep->ep);
1682                 if (likely(!ret)) {
1683                         epfile->ep = ep;
1684                         epfile->in = usb_endpoint_dir_in(ds);
1685                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1686                 } else {
1687                         break;
1688                 }
1689
1690                 wake_up(&epfile->wait);
1691
1692                 ++ep;
1693                 ++epfile;
1694         } while (--count);
1695         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1696
1697         return ret;
1698 }
1699
1700
1701 /* Parsing and building descriptors and strings *****************************/
1702
1703 /*
1704  * This validates if data pointed by data is a valid USB descriptor as
1705  * well as record how many interfaces, endpoints and strings are
1706  * required by given configuration.  Returns address after the
1707  * descriptor or NULL if data is invalid.
1708  */
1709
1710 enum ffs_entity_type {
1711         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1712 };
1713
1714 enum ffs_os_desc_type {
1715         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1716 };
1717
1718 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1719                                    u8 *valuep,
1720                                    struct usb_descriptor_header *desc,
1721                                    void *priv);
1722
1723 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1724                                     struct usb_os_desc_header *h, void *data,
1725                                     unsigned len, void *priv);
1726
1727 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1728                                            ffs_entity_callback entity,
1729                                            void *priv)
1730 {
1731         struct usb_descriptor_header *_ds = (void *)data;
1732         u8 length;
1733         int ret;
1734
1735         ENTER();
1736
1737         /* At least two bytes are required: length and type */
1738         if (len < 2) {
1739                 pr_vdebug("descriptor too short\n");
1740                 return -EINVAL;
1741         }
1742
1743         /* If we have at least as many bytes as the descriptor takes? */
1744         length = _ds->bLength;
1745         if (len < length) {
1746                 pr_vdebug("descriptor longer then available data\n");
1747                 return -EINVAL;
1748         }
1749
1750 #define __entity_check_INTERFACE(val)  1
1751 #define __entity_check_STRING(val)     (val)
1752 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1753 #define __entity(type, val) do {                                        \
1754                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1755                 if (unlikely(!__entity_check_ ##type(val))) {           \
1756                         pr_vdebug("invalid entity's value\n");          \
1757                         return -EINVAL;                                 \
1758                 }                                                       \
1759                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1760                 if (unlikely(ret < 0)) {                                \
1761                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1762                                  (val), ret);                           \
1763                         return ret;                                     \
1764                 }                                                       \
1765         } while (0)
1766
1767         /* Parse descriptor depending on type. */
1768         switch (_ds->bDescriptorType) {
1769         case USB_DT_DEVICE:
1770         case USB_DT_CONFIG:
1771         case USB_DT_STRING:
1772         case USB_DT_DEVICE_QUALIFIER:
1773                 /* function can't have any of those */
1774                 pr_vdebug("descriptor reserved for gadget: %d\n",
1775                       _ds->bDescriptorType);
1776                 return -EINVAL;
1777
1778         case USB_DT_INTERFACE: {
1779                 struct usb_interface_descriptor *ds = (void *)_ds;
1780                 pr_vdebug("interface descriptor\n");
1781                 if (length != sizeof *ds)
1782                         goto inv_length;
1783
1784                 __entity(INTERFACE, ds->bInterfaceNumber);
1785                 if (ds->iInterface)
1786                         __entity(STRING, ds->iInterface);
1787         }
1788                 break;
1789
1790         case USB_DT_ENDPOINT: {
1791                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1792                 pr_vdebug("endpoint descriptor\n");
1793                 if (length != USB_DT_ENDPOINT_SIZE &&
1794                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1795                         goto inv_length;
1796                 __entity(ENDPOINT, ds->bEndpointAddress);
1797         }
1798                 break;
1799
1800         case HID_DT_HID:
1801                 pr_vdebug("hid descriptor\n");
1802                 if (length != sizeof(struct hid_descriptor))
1803                         goto inv_length;
1804                 break;
1805
1806         case USB_DT_OTG:
1807                 if (length != sizeof(struct usb_otg_descriptor))
1808                         goto inv_length;
1809                 break;
1810
1811         case USB_DT_INTERFACE_ASSOCIATION: {
1812                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1813                 pr_vdebug("interface association descriptor\n");
1814                 if (length != sizeof *ds)
1815                         goto inv_length;
1816                 if (ds->iFunction)
1817                         __entity(STRING, ds->iFunction);
1818         }
1819                 break;
1820
1821         case USB_DT_SS_ENDPOINT_COMP:
1822                 pr_vdebug("EP SS companion descriptor\n");
1823                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
1824                         goto inv_length;
1825                 break;
1826
1827         case USB_DT_OTHER_SPEED_CONFIG:
1828         case USB_DT_INTERFACE_POWER:
1829         case USB_DT_DEBUG:
1830         case USB_DT_SECURITY:
1831         case USB_DT_CS_RADIO_CONTROL:
1832                 /* TODO */
1833                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1834                 return -EINVAL;
1835
1836         default:
1837                 /* We should never be here */
1838                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1839                 return -EINVAL;
1840
1841 inv_length:
1842                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1843                           _ds->bLength, _ds->bDescriptorType);
1844                 return -EINVAL;
1845         }
1846
1847 #undef __entity
1848 #undef __entity_check_DESCRIPTOR
1849 #undef __entity_check_INTERFACE
1850 #undef __entity_check_STRING
1851 #undef __entity_check_ENDPOINT
1852
1853         return length;
1854 }
1855
1856 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1857                                      ffs_entity_callback entity, void *priv)
1858 {
1859         const unsigned _len = len;
1860         unsigned long num = 0;
1861
1862         ENTER();
1863
1864         for (;;) {
1865                 int ret;
1866
1867                 if (num == count)
1868                         data = NULL;
1869
1870                 /* Record "descriptor" entity */
1871                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1872                 if (unlikely(ret < 0)) {
1873                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1874                                  num, ret);
1875                         return ret;
1876                 }
1877
1878                 if (!data)
1879                         return _len - len;
1880
1881                 ret = ffs_do_single_desc(data, len, entity, priv);
1882                 if (unlikely(ret < 0)) {
1883                         pr_debug("%s returns %d\n", __func__, ret);
1884                         return ret;
1885                 }
1886
1887                 len -= ret;
1888                 data += ret;
1889                 ++num;
1890         }
1891 }
1892
1893 static int __ffs_data_do_entity(enum ffs_entity_type type,
1894                                 u8 *valuep, struct usb_descriptor_header *desc,
1895                                 void *priv)
1896 {
1897         struct ffs_desc_helper *helper = priv;
1898         struct usb_endpoint_descriptor *d;
1899
1900         ENTER();
1901
1902         switch (type) {
1903         case FFS_DESCRIPTOR:
1904                 break;
1905
1906         case FFS_INTERFACE:
1907                 /*
1908                  * Interfaces are indexed from zero so if we
1909                  * encountered interface "n" then there are at least
1910                  * "n+1" interfaces.
1911                  */
1912                 if (*valuep >= helper->interfaces_count)
1913                         helper->interfaces_count = *valuep + 1;
1914                 break;
1915
1916         case FFS_STRING:
1917                 /*
1918                  * Strings are indexed from 1 (0 is magic ;) reserved
1919                  * for languages list or some such)
1920                  */
1921                 if (*valuep > helper->ffs->strings_count)
1922                         helper->ffs->strings_count = *valuep;
1923                 break;
1924
1925         case FFS_ENDPOINT:
1926                 d = (void *)desc;
1927                 helper->eps_count++;
1928                 if (helper->eps_count >= 15)
1929                         return -EINVAL;
1930                 /* Check if descriptors for any speed were already parsed */
1931                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
1932                         helper->ffs->eps_addrmap[helper->eps_count] =
1933                                 d->bEndpointAddress;
1934                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
1935                                 d->bEndpointAddress)
1936                         return -EINVAL;
1937                 break;
1938         }
1939
1940         return 0;
1941 }
1942
1943 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
1944                                    struct usb_os_desc_header *desc)
1945 {
1946         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
1947         u16 w_index = le16_to_cpu(desc->wIndex);
1948
1949         if (bcd_version != 1) {
1950                 pr_vdebug("unsupported os descriptors version: %d",
1951                           bcd_version);
1952                 return -EINVAL;
1953         }
1954         switch (w_index) {
1955         case 0x4:
1956                 *next_type = FFS_OS_DESC_EXT_COMPAT;
1957                 break;
1958         case 0x5:
1959                 *next_type = FFS_OS_DESC_EXT_PROP;
1960                 break;
1961         default:
1962                 pr_vdebug("unsupported os descriptor type: %d", w_index);
1963                 return -EINVAL;
1964         }
1965
1966         return sizeof(*desc);
1967 }
1968
1969 /*
1970  * Process all extended compatibility/extended property descriptors
1971  * of a feature descriptor
1972  */
1973 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
1974                                               enum ffs_os_desc_type type,
1975                                               u16 feature_count,
1976                                               ffs_os_desc_callback entity,
1977                                               void *priv,
1978                                               struct usb_os_desc_header *h)
1979 {
1980         int ret;
1981         const unsigned _len = len;
1982
1983         ENTER();
1984
1985         /* loop over all ext compat/ext prop descriptors */
1986         while (feature_count--) {
1987                 ret = entity(type, h, data, len, priv);
1988                 if (unlikely(ret < 0)) {
1989                         pr_debug("bad OS descriptor, type: %d\n", type);
1990                         return ret;
1991                 }
1992                 data += ret;
1993                 len -= ret;
1994         }
1995         return _len - len;
1996 }
1997
1998 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
1999 static int __must_check ffs_do_os_descs(unsigned count,
2000                                         char *data, unsigned len,
2001                                         ffs_os_desc_callback entity, void *priv)
2002 {
2003         const unsigned _len = len;
2004         unsigned long num = 0;
2005
2006         ENTER();
2007
2008         for (num = 0; num < count; ++num) {
2009                 int ret;
2010                 enum ffs_os_desc_type type;
2011                 u16 feature_count;
2012                 struct usb_os_desc_header *desc = (void *)data;
2013
2014                 if (len < sizeof(*desc))
2015                         return -EINVAL;
2016
2017                 /*
2018                  * Record "descriptor" entity.
2019                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2020                  * Move the data pointer to the beginning of extended
2021                  * compatibilities proper or extended properties proper
2022                  * portions of the data
2023                  */
2024                 if (le32_to_cpu(desc->dwLength) > len)
2025                         return -EINVAL;
2026
2027                 ret = __ffs_do_os_desc_header(&type, desc);
2028                 if (unlikely(ret < 0)) {
2029                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2030                                  num, ret);
2031                         return ret;
2032                 }
2033                 /*
2034                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2035                  */
2036                 feature_count = le16_to_cpu(desc->wCount);
2037                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2038                     (feature_count > 255 || desc->Reserved))
2039                                 return -EINVAL;
2040                 len -= ret;
2041                 data += ret;
2042
2043                 /*
2044                  * Process all function/property descriptors
2045                  * of this Feature Descriptor
2046                  */
2047                 ret = ffs_do_single_os_desc(data, len, type,
2048                                             feature_count, entity, priv, desc);
2049                 if (unlikely(ret < 0)) {
2050                         pr_debug("%s returns %d\n", __func__, ret);
2051                         return ret;
2052                 }
2053
2054                 len -= ret;
2055                 data += ret;
2056         }
2057         return _len - len;
2058 }
2059
2060 /**
2061  * Validate contents of the buffer from userspace related to OS descriptors.
2062  */
2063 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2064                                  struct usb_os_desc_header *h, void *data,
2065                                  unsigned len, void *priv)
2066 {
2067         struct ffs_data *ffs = priv;
2068         u8 length;
2069
2070         ENTER();
2071
2072         switch (type) {
2073         case FFS_OS_DESC_EXT_COMPAT: {
2074                 struct usb_ext_compat_desc *d = data;
2075                 int i;
2076
2077                 if (len < sizeof(*d) ||
2078                     d->bFirstInterfaceNumber >= ffs->interfaces_count ||
2079                     d->Reserved1)
2080                         return -EINVAL;
2081                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2082                         if (d->Reserved2[i])
2083                                 return -EINVAL;
2084
2085                 length = sizeof(struct usb_ext_compat_desc);
2086         }
2087                 break;
2088         case FFS_OS_DESC_EXT_PROP: {
2089                 struct usb_ext_prop_desc *d = data;
2090                 u32 type, pdl;
2091                 u16 pnl;
2092
2093                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2094                         return -EINVAL;
2095                 length = le32_to_cpu(d->dwSize);
2096                 if (len < length)
2097                         return -EINVAL;
2098                 type = le32_to_cpu(d->dwPropertyDataType);
2099                 if (type < USB_EXT_PROP_UNICODE ||
2100                     type > USB_EXT_PROP_UNICODE_MULTI) {
2101                         pr_vdebug("unsupported os descriptor property type: %d",
2102                                   type);
2103                         return -EINVAL;
2104                 }
2105                 pnl = le16_to_cpu(d->wPropertyNameLength);
2106                 if (length < 14 + pnl) {
2107                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2108                                   length, pnl, type);
2109                         return -EINVAL;
2110                 }
2111                 pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
2112                 if (length != 14 + pnl + pdl) {
2113                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2114                                   length, pnl, pdl, type);
2115                         return -EINVAL;
2116                 }
2117                 ++ffs->ms_os_descs_ext_prop_count;
2118                 /* property name reported to the host as "WCHAR"s */
2119                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2120                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2121         }
2122                 break;
2123         default:
2124                 pr_vdebug("unknown descriptor: %d\n", type);
2125                 return -EINVAL;
2126         }
2127         return length;
2128 }
2129
2130 static int __ffs_data_got_descs(struct ffs_data *ffs,
2131                                 char *const _data, size_t len)
2132 {
2133         char *data = _data, *raw_descs;
2134         unsigned os_descs_count = 0, counts[3], flags;
2135         int ret = -EINVAL, i;
2136         struct ffs_desc_helper helper;
2137
2138         ENTER();
2139
2140         if (get_unaligned_le32(data + 4) != len)
2141                 goto error;
2142
2143         switch (get_unaligned_le32(data)) {
2144         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2145                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2146                 data += 8;
2147                 len  -= 8;
2148                 break;
2149         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2150                 flags = get_unaligned_le32(data + 8);
2151                 ffs->user_flags = flags;
2152                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2153                               FUNCTIONFS_HAS_HS_DESC |
2154                               FUNCTIONFS_HAS_SS_DESC |
2155                               FUNCTIONFS_HAS_MS_OS_DESC |
2156                               FUNCTIONFS_VIRTUAL_ADDR |
2157                               FUNCTIONFS_EVENTFD)) {
2158                         ret = -ENOSYS;
2159                         goto error;
2160                 }
2161                 data += 12;
2162                 len  -= 12;
2163                 break;
2164         default:
2165                 goto error;
2166         }
2167
2168         if (flags & FUNCTIONFS_EVENTFD) {
2169                 if (len < 4)
2170                         goto error;
2171                 ffs->ffs_eventfd =
2172                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2173                 if (IS_ERR(ffs->ffs_eventfd)) {
2174                         ret = PTR_ERR(ffs->ffs_eventfd);
2175                         ffs->ffs_eventfd = NULL;
2176                         goto error;
2177                 }
2178                 data += 4;
2179                 len  -= 4;
2180         }
2181
2182         /* Read fs_count, hs_count and ss_count (if present) */
2183         for (i = 0; i < 3; ++i) {
2184                 if (!(flags & (1 << i))) {
2185                         counts[i] = 0;
2186                 } else if (len < 4) {
2187                         goto error;
2188                 } else {
2189                         counts[i] = get_unaligned_le32(data);
2190                         data += 4;
2191                         len  -= 4;
2192                 }
2193         }
2194         if (flags & (1 << i)) {
2195                 if (len < 4) {
2196                         goto error;
2197                 }
2198                 os_descs_count = get_unaligned_le32(data);
2199                 data += 4;
2200                 len -= 4;
2201         };
2202
2203         /* Read descriptors */
2204         raw_descs = data;
2205         helper.ffs = ffs;
2206         for (i = 0; i < 3; ++i) {
2207                 if (!counts[i])
2208                         continue;
2209                 helper.interfaces_count = 0;
2210                 helper.eps_count = 0;
2211                 ret = ffs_do_descs(counts[i], data, len,
2212                                    __ffs_data_do_entity, &helper);
2213                 if (ret < 0)
2214                         goto error;
2215                 if (!ffs->eps_count && !ffs->interfaces_count) {
2216                         ffs->eps_count = helper.eps_count;
2217                         ffs->interfaces_count = helper.interfaces_count;
2218                 } else {
2219                         if (ffs->eps_count != helper.eps_count) {
2220                                 ret = -EINVAL;
2221                                 goto error;
2222                         }
2223                         if (ffs->interfaces_count != helper.interfaces_count) {
2224                                 ret = -EINVAL;
2225                                 goto error;
2226                         }
2227                 }
2228                 data += ret;
2229                 len  -= ret;
2230         }
2231         if (os_descs_count) {
2232                 ret = ffs_do_os_descs(os_descs_count, data, len,
2233                                       __ffs_data_do_os_desc, ffs);
2234                 if (ret < 0)
2235                         goto error;
2236                 data += ret;
2237                 len -= ret;
2238         }
2239
2240         if (raw_descs == data || len) {
2241                 ret = -EINVAL;
2242                 goto error;
2243         }
2244
2245         ffs->raw_descs_data     = _data;
2246         ffs->raw_descs          = raw_descs;
2247         ffs->raw_descs_length   = data - raw_descs;
2248         ffs->fs_descs_count     = counts[0];
2249         ffs->hs_descs_count     = counts[1];
2250         ffs->ss_descs_count     = counts[2];
2251         ffs->ms_os_descs_count  = os_descs_count;
2252
2253         return 0;
2254
2255 error:
2256         kfree(_data);
2257         return ret;
2258 }
2259
2260 static int __ffs_data_got_strings(struct ffs_data *ffs,
2261                                   char *const _data, size_t len)
2262 {
2263         u32 str_count, needed_count, lang_count;
2264         struct usb_gadget_strings **stringtabs, *t;
2265         struct usb_string *strings, *s;
2266         const char *data = _data;
2267
2268         ENTER();
2269
2270         if (unlikely(len < 16 ||
2271                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2272                      get_unaligned_le32(data + 4) != len))
2273                 goto error;
2274         str_count  = get_unaligned_le32(data + 8);
2275         lang_count = get_unaligned_le32(data + 12);
2276
2277         /* if one is zero the other must be zero */
2278         if (unlikely(!str_count != !lang_count))
2279                 goto error;
2280
2281         /* Do we have at least as many strings as descriptors need? */
2282         needed_count = ffs->strings_count;
2283         if (unlikely(str_count < needed_count))
2284                 goto error;
2285
2286         /*
2287          * If we don't need any strings just return and free all
2288          * memory.
2289          */
2290         if (!needed_count) {
2291                 kfree(_data);
2292                 return 0;
2293         }
2294
2295         /* Allocate everything in one chunk so there's less maintenance. */
2296         {
2297                 unsigned i = 0;
2298                 vla_group(d);
2299                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2300                         lang_count + 1);
2301                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2302                 vla_item(d, struct usb_string, strings,
2303                         lang_count*(needed_count+1));
2304
2305                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2306
2307                 if (unlikely(!vlabuf)) {
2308                         kfree(_data);
2309                         return -ENOMEM;
2310                 }
2311
2312                 /* Initialize the VLA pointers */
2313                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2314                 t = vla_ptr(vlabuf, d, stringtab);
2315                 i = lang_count;
2316                 do {
2317                         *stringtabs++ = t++;
2318                 } while (--i);
2319                 *stringtabs = NULL;
2320
2321                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2322                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2323                 t = vla_ptr(vlabuf, d, stringtab);
2324                 s = vla_ptr(vlabuf, d, strings);
2325                 strings = s;
2326         }
2327
2328         /* For each language */
2329         data += 16;
2330         len -= 16;
2331
2332         do { /* lang_count > 0 so we can use do-while */
2333                 unsigned needed = needed_count;
2334
2335                 if (unlikely(len < 3))
2336                         goto error_free;
2337                 t->language = get_unaligned_le16(data);
2338                 t->strings  = s;
2339                 ++t;
2340
2341                 data += 2;
2342                 len -= 2;
2343
2344                 /* For each string */
2345                 do { /* str_count > 0 so we can use do-while */
2346                         size_t length = strnlen(data, len);
2347
2348                         if (unlikely(length == len))
2349                                 goto error_free;
2350
2351                         /*
2352                          * User may provide more strings then we need,
2353                          * if that's the case we simply ignore the
2354                          * rest
2355                          */
2356                         if (likely(needed)) {
2357                                 /*
2358                                  * s->id will be set while adding
2359                                  * function to configuration so for
2360                                  * now just leave garbage here.
2361                                  */
2362                                 s->s = data;
2363                                 --needed;
2364                                 ++s;
2365                         }
2366
2367                         data += length + 1;
2368                         len -= length + 1;
2369                 } while (--str_count);
2370
2371                 s->id = 0;   /* terminator */
2372                 s->s = NULL;
2373                 ++s;
2374
2375         } while (--lang_count);
2376
2377         /* Some garbage left? */
2378         if (unlikely(len))
2379                 goto error_free;
2380
2381         /* Done! */
2382         ffs->stringtabs = stringtabs;
2383         ffs->raw_strings = _data;
2384
2385         return 0;
2386
2387 error_free:
2388         kfree(stringtabs);
2389 error:
2390         kfree(_data);
2391         return -EINVAL;
2392 }
2393
2394
2395 /* Events handling and management *******************************************/
2396
2397 static void __ffs_event_add(struct ffs_data *ffs,
2398                             enum usb_functionfs_event_type type)
2399 {
2400         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2401         int neg = 0;
2402
2403         /*
2404          * Abort any unhandled setup
2405          *
2406          * We do not need to worry about some cmpxchg() changing value
2407          * of ffs->setup_state without holding the lock because when
2408          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2409          * the source does nothing.
2410          */
2411         if (ffs->setup_state == FFS_SETUP_PENDING)
2412                 ffs->setup_state = FFS_SETUP_CANCELLED;
2413
2414         /*
2415          * Logic of this function guarantees that there are at most four pending
2416          * evens on ffs->ev.types queue.  This is important because the queue
2417          * has space for four elements only and __ffs_ep0_read_events function
2418          * depends on that limit as well.  If more event types are added, those
2419          * limits have to be revisited or guaranteed to still hold.
2420          */
2421         switch (type) {
2422         case FUNCTIONFS_RESUME:
2423                 rem_type2 = FUNCTIONFS_SUSPEND;
2424                 /* FALL THROUGH */
2425         case FUNCTIONFS_SUSPEND:
2426         case FUNCTIONFS_SETUP:
2427                 rem_type1 = type;
2428                 /* Discard all similar events */
2429                 break;
2430
2431         case FUNCTIONFS_BIND:
2432         case FUNCTIONFS_UNBIND:
2433         case FUNCTIONFS_DISABLE:
2434         case FUNCTIONFS_ENABLE:
2435                 /* Discard everything other then power management. */
2436                 rem_type1 = FUNCTIONFS_SUSPEND;
2437                 rem_type2 = FUNCTIONFS_RESUME;
2438                 neg = 1;
2439                 break;
2440
2441         default:
2442                 WARN(1, "%d: unknown event, this should not happen\n", type);
2443                 return;
2444         }
2445
2446         {
2447                 u8 *ev  = ffs->ev.types, *out = ev;
2448                 unsigned n = ffs->ev.count;
2449                 for (; n; --n, ++ev)
2450                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2451                                 *out++ = *ev;
2452                         else
2453                                 pr_vdebug("purging event %d\n", *ev);
2454                 ffs->ev.count = out - ffs->ev.types;
2455         }
2456
2457         pr_vdebug("adding event %d\n", type);
2458         ffs->ev.types[ffs->ev.count++] = type;
2459         wake_up_locked(&ffs->ev.waitq);
2460         if (ffs->ffs_eventfd)
2461                 eventfd_signal(ffs->ffs_eventfd, 1);
2462 }
2463
2464 static void ffs_event_add(struct ffs_data *ffs,
2465                           enum usb_functionfs_event_type type)
2466 {
2467         unsigned long flags;
2468         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2469         __ffs_event_add(ffs, type);
2470         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2471 }
2472
2473 /* Bind/unbind USB function hooks *******************************************/
2474
2475 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2476 {
2477         int i;
2478
2479         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2480                 if (ffs->eps_addrmap[i] == endpoint_address)
2481                         return i;
2482         return -ENOENT;
2483 }
2484
2485 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2486                                     struct usb_descriptor_header *desc,
2487                                     void *priv)
2488 {
2489         struct usb_endpoint_descriptor *ds = (void *)desc;
2490         struct ffs_function *func = priv;
2491         struct ffs_ep *ffs_ep;
2492         unsigned ep_desc_id;
2493         int idx;
2494         static const char *speed_names[] = { "full", "high", "super" };
2495
2496         if (type != FFS_DESCRIPTOR)
2497                 return 0;
2498
2499         /*
2500          * If ss_descriptors is not NULL, we are reading super speed
2501          * descriptors; if hs_descriptors is not NULL, we are reading high
2502          * speed descriptors; otherwise, we are reading full speed
2503          * descriptors.
2504          */
2505         if (func->function.ss_descriptors) {
2506                 ep_desc_id = 2;
2507                 func->function.ss_descriptors[(long)valuep] = desc;
2508         } else if (func->function.hs_descriptors) {
2509                 ep_desc_id = 1;
2510                 func->function.hs_descriptors[(long)valuep] = desc;
2511         } else {
2512                 ep_desc_id = 0;
2513                 func->function.fs_descriptors[(long)valuep]    = desc;
2514         }
2515
2516         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2517                 return 0;
2518
2519         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2520         if (idx < 0)
2521                 return idx;
2522
2523         ffs_ep = func->eps + idx;
2524
2525         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2526                 pr_err("two %sspeed descriptors for EP %d\n",
2527                           speed_names[ep_desc_id],
2528                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2529                 return -EINVAL;
2530         }
2531         ffs_ep->descs[ep_desc_id] = ds;
2532
2533         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2534         if (ffs_ep->ep) {
2535                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2536                 if (!ds->wMaxPacketSize)
2537                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2538         } else {
2539                 struct usb_request *req;
2540                 struct usb_ep *ep;
2541                 u8 bEndpointAddress;
2542
2543                 /*
2544                  * We back up bEndpointAddress because autoconfig overwrites
2545                  * it with physical endpoint address.
2546                  */
2547                 bEndpointAddress = ds->bEndpointAddress;
2548                 pr_vdebug("autoconfig\n");
2549                 ep = usb_ep_autoconfig(func->gadget, ds);
2550                 if (unlikely(!ep))
2551                         return -ENOTSUPP;
2552                 ep->driver_data = func->eps + idx;
2553
2554                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2555                 if (unlikely(!req))
2556                         return -ENOMEM;
2557
2558                 ffs_ep->ep  = ep;
2559                 ffs_ep->req = req;
2560                 func->eps_revmap[ds->bEndpointAddress &
2561                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2562                 /*
2563                  * If we use virtual address mapping, we restore
2564                  * original bEndpointAddress value.
2565                  */
2566                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2567                         ds->bEndpointAddress = bEndpointAddress;
2568         }
2569         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2570
2571         return 0;
2572 }
2573
2574 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2575                                    struct usb_descriptor_header *desc,
2576                                    void *priv)
2577 {
2578         struct ffs_function *func = priv;
2579         unsigned idx;
2580         u8 newValue;
2581
2582         switch (type) {
2583         default:
2584         case FFS_DESCRIPTOR:
2585                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2586                 return 0;
2587
2588         case FFS_INTERFACE:
2589                 idx = *valuep;
2590                 if (func->interfaces_nums[idx] < 0) {
2591                         int id = usb_interface_id(func->conf, &func->function);
2592                         if (unlikely(id < 0))
2593                                 return id;
2594                         func->interfaces_nums[idx] = id;
2595                 }
2596                 newValue = func->interfaces_nums[idx];
2597                 break;
2598
2599         case FFS_STRING:
2600                 /* String' IDs are allocated when fsf_data is bound to cdev */
2601                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2602                 break;
2603
2604         case FFS_ENDPOINT:
2605                 /*
2606                  * USB_DT_ENDPOINT are handled in
2607                  * __ffs_func_bind_do_descs().
2608                  */
2609                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2610                         return 0;
2611
2612                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2613                 if (unlikely(!func->eps[idx].ep))
2614                         return -EINVAL;
2615
2616                 {
2617                         struct usb_endpoint_descriptor **descs;
2618                         descs = func->eps[idx].descs;
2619                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2620                 }
2621                 break;
2622         }
2623
2624         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2625         *valuep = newValue;
2626         return 0;
2627 }
2628
2629 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2630                                       struct usb_os_desc_header *h, void *data,
2631                                       unsigned len, void *priv)
2632 {
2633         struct ffs_function *func = priv;
2634         u8 length = 0;
2635
2636         switch (type) {
2637         case FFS_OS_DESC_EXT_COMPAT: {
2638                 struct usb_ext_compat_desc *desc = data;
2639                 struct usb_os_desc_table *t;
2640
2641                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2642                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2643                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2644                        ARRAY_SIZE(desc->CompatibleID) +
2645                        ARRAY_SIZE(desc->SubCompatibleID));
2646                 length = sizeof(*desc);
2647         }
2648                 break;
2649         case FFS_OS_DESC_EXT_PROP: {
2650                 struct usb_ext_prop_desc *desc = data;
2651                 struct usb_os_desc_table *t;
2652                 struct usb_os_desc_ext_prop *ext_prop;
2653                 char *ext_prop_name;
2654                 char *ext_prop_data;
2655
2656                 t = &func->function.os_desc_table[h->interface];
2657                 t->if_id = func->interfaces_nums[h->interface];
2658
2659                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2660                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2661
2662                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2663                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2664                 ext_prop->data_len = le32_to_cpu(*(u32 *)
2665                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2666                 length = ext_prop->name_len + ext_prop->data_len + 14;
2667
2668                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2669                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2670                         ext_prop->name_len;
2671
2672                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2673                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2674                         ext_prop->data_len;
2675                 memcpy(ext_prop_data,
2676                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2677                        ext_prop->data_len);
2678                 /* unicode data reported to the host as "WCHAR"s */
2679                 switch (ext_prop->type) {
2680                 case USB_EXT_PROP_UNICODE:
2681                 case USB_EXT_PROP_UNICODE_ENV:
2682                 case USB_EXT_PROP_UNICODE_LINK:
2683                 case USB_EXT_PROP_UNICODE_MULTI:
2684                         ext_prop->data_len *= 2;
2685                         break;
2686                 }
2687                 ext_prop->data = ext_prop_data;
2688
2689                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2690                        ext_prop->name_len);
2691                 /* property name reported to the host as "WCHAR"s */
2692                 ext_prop->name_len *= 2;
2693                 ext_prop->name = ext_prop_name;
2694
2695                 t->os_desc->ext_prop_len +=
2696                         ext_prop->name_len + ext_prop->data_len + 14;
2697                 ++t->os_desc->ext_prop_count;
2698                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2699         }
2700                 break;
2701         default:
2702                 pr_vdebug("unknown descriptor: %d\n", type);
2703         }
2704
2705         return length;
2706 }
2707
2708 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2709                                                 struct usb_configuration *c)
2710 {
2711         struct ffs_function *func = ffs_func_from_usb(f);
2712         struct f_fs_opts *ffs_opts =
2713                 container_of(f->fi, struct f_fs_opts, func_inst);
2714         int ret;
2715
2716         ENTER();
2717
2718         /*
2719          * Legacy gadget triggers binding in functionfs_ready_callback,
2720          * which already uses locking; taking the same lock here would
2721          * cause a deadlock.
2722          *
2723          * Configfs-enabled gadgets however do need ffs_dev_lock.
2724          */
2725         if (!ffs_opts->no_configfs)
2726                 ffs_dev_lock();
2727         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2728         func->ffs = ffs_opts->dev->ffs_data;
2729         if (!ffs_opts->no_configfs)
2730                 ffs_dev_unlock();
2731         if (ret)
2732                 return ERR_PTR(ret);
2733
2734         func->conf = c;
2735         func->gadget = c->cdev->gadget;
2736
2737         /*
2738          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2739          * configurations are bound in sequence with list_for_each_entry,
2740          * in each configuration its functions are bound in sequence
2741          * with list_for_each_entry, so we assume no race condition
2742          * with regard to ffs_opts->bound access
2743          */
2744         if (!ffs_opts->refcnt) {
2745                 ret = functionfs_bind(func->ffs, c->cdev);
2746                 if (ret)
2747                         return ERR_PTR(ret);
2748         }
2749         ffs_opts->refcnt++;
2750         func->function.strings = func->ffs->stringtabs;
2751
2752         return ffs_opts;
2753 }
2754
2755 static int _ffs_func_bind(struct usb_configuration *c,
2756                           struct usb_function *f)
2757 {
2758         struct ffs_function *func = ffs_func_from_usb(f);
2759         struct ffs_data *ffs = func->ffs;
2760
2761         const int full = !!func->ffs->fs_descs_count;
2762         const int high = !!func->ffs->hs_descs_count;
2763         const int super = !!func->ffs->ss_descs_count;
2764
2765         int fs_len, hs_len, ss_len, ret, i;
2766         struct ffs_ep *eps_ptr;
2767
2768         /* Make it a single chunk, less management later on */
2769         vla_group(d);
2770         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2771         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2772                 full ? ffs->fs_descs_count + 1 : 0);
2773         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2774                 high ? ffs->hs_descs_count + 1 : 0);
2775         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2776                 super ? ffs->ss_descs_count + 1 : 0);
2777         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2778         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2779                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2780         vla_item_with_sz(d, char[16], ext_compat,
2781                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2782         vla_item_with_sz(d, struct usb_os_desc, os_desc,
2783                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2784         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
2785                          ffs->ms_os_descs_ext_prop_count);
2786         vla_item_with_sz(d, char, ext_prop_name,
2787                          ffs->ms_os_descs_ext_prop_name_len);
2788         vla_item_with_sz(d, char, ext_prop_data,
2789                          ffs->ms_os_descs_ext_prop_data_len);
2790         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2791         char *vlabuf;
2792
2793         ENTER();
2794
2795         /* Has descriptors only for speeds gadget does not support */
2796         if (unlikely(!(full | high | super)))
2797                 return -ENOTSUPP;
2798
2799         /* Allocate a single chunk, less management later on */
2800         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
2801         if (unlikely(!vlabuf))
2802                 return -ENOMEM;
2803
2804         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
2805         ffs->ms_os_descs_ext_prop_name_avail =
2806                 vla_ptr(vlabuf, d, ext_prop_name);
2807         ffs->ms_os_descs_ext_prop_data_avail =
2808                 vla_ptr(vlabuf, d, ext_prop_data);
2809
2810         /* Copy descriptors  */
2811         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
2812                ffs->raw_descs_length);
2813
2814         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2815         eps_ptr = vla_ptr(vlabuf, d, eps);
2816         for (i = 0; i < ffs->eps_count; i++)
2817                 eps_ptr[i].num = -1;
2818
2819         /* Save pointers
2820          * d_eps == vlabuf, func->eps used to kfree vlabuf later
2821         */
2822         func->eps             = vla_ptr(vlabuf, d, eps);
2823         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
2824
2825         /*
2826          * Go through all the endpoint descriptors and allocate
2827          * endpoints first, so that later we can rewrite the endpoint
2828          * numbers without worrying that it may be described later on.
2829          */
2830         if (likely(full)) {
2831                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
2832                 fs_len = ffs_do_descs(ffs->fs_descs_count,
2833                                       vla_ptr(vlabuf, d, raw_descs),
2834                                       d_raw_descs__sz,
2835                                       __ffs_func_bind_do_descs, func);
2836                 if (unlikely(fs_len < 0)) {
2837                         ret = fs_len;
2838                         goto error;
2839                 }
2840         } else {
2841                 fs_len = 0;
2842         }
2843
2844         if (likely(high)) {
2845                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
2846                 hs_len = ffs_do_descs(ffs->hs_descs_count,
2847                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
2848                                       d_raw_descs__sz - fs_len,
2849                                       __ffs_func_bind_do_descs, func);
2850                 if (unlikely(hs_len < 0)) {
2851                         ret = hs_len;
2852                         goto error;
2853                 }
2854         } else {
2855                 hs_len = 0;
2856         }
2857
2858         if (likely(super)) {
2859                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
2860                 ss_len = ffs_do_descs(ffs->ss_descs_count,
2861                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
2862                                 d_raw_descs__sz - fs_len - hs_len,
2863                                 __ffs_func_bind_do_descs, func);
2864                 if (unlikely(ss_len < 0)) {
2865                         ret = ss_len;
2866                         goto error;
2867                 }
2868         } else {
2869                 ss_len = 0;
2870         }
2871
2872         /*
2873          * Now handle interface numbers allocation and interface and
2874          * endpoint numbers rewriting.  We can do that in one go
2875          * now.
2876          */
2877         ret = ffs_do_descs(ffs->fs_descs_count +
2878                            (high ? ffs->hs_descs_count : 0) +
2879                            (super ? ffs->ss_descs_count : 0),
2880                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
2881                            __ffs_func_bind_do_nums, func);
2882         if (unlikely(ret < 0))
2883                 goto error;
2884
2885         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
2886         if (c->cdev->use_os_string)
2887                 for (i = 0; i < ffs->interfaces_count; ++i) {
2888                         struct usb_os_desc *desc;
2889
2890                         desc = func->function.os_desc_table[i].os_desc =
2891                                 vla_ptr(vlabuf, d, os_desc) +
2892                                 i * sizeof(struct usb_os_desc);
2893                         desc->ext_compat_id =
2894                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
2895                         INIT_LIST_HEAD(&desc->ext_prop);
2896                 }
2897         ret = ffs_do_os_descs(ffs->ms_os_descs_count,
2898                               vla_ptr(vlabuf, d, raw_descs) +
2899                               fs_len + hs_len + ss_len,
2900                               d_raw_descs__sz - fs_len - hs_len - ss_len,
2901                               __ffs_func_bind_do_os_desc, func);
2902         if (unlikely(ret < 0))
2903                 goto error;
2904         func->function.os_desc_n =
2905                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
2906
2907         /* And we're done */
2908         ffs_event_add(ffs, FUNCTIONFS_BIND);
2909         return 0;
2910
2911 error:
2912         /* XXX Do we need to release all claimed endpoints here? */
2913         return ret;
2914 }
2915
2916 static int ffs_func_bind(struct usb_configuration *c,
2917                          struct usb_function *f)
2918 {
2919         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
2920         struct ffs_function *func = ffs_func_from_usb(f);
2921         int ret;
2922
2923         if (IS_ERR(ffs_opts))
2924                 return PTR_ERR(ffs_opts);
2925
2926         ret = _ffs_func_bind(c, f);
2927         if (ret && !--ffs_opts->refcnt)
2928                 functionfs_unbind(func->ffs);
2929
2930         return ret;
2931 }
2932
2933
2934 /* Other USB function hooks *************************************************/
2935
2936 static void ffs_reset_work(struct work_struct *work)
2937 {
2938         struct ffs_data *ffs = container_of(work,
2939                 struct ffs_data, reset_work);
2940         ffs_data_reset(ffs);
2941 }
2942
2943 static int ffs_func_set_alt(struct usb_function *f,
2944                             unsigned interface, unsigned alt)
2945 {
2946         struct ffs_function *func = ffs_func_from_usb(f);
2947         struct ffs_data *ffs = func->ffs;
2948         int ret = 0, intf;
2949
2950         if (alt != (unsigned)-1) {
2951                 intf = ffs_func_revmap_intf(func, interface);
2952                 if (unlikely(intf < 0))
2953                         return intf;
2954         }
2955
2956         if (ffs->func)
2957                 ffs_func_eps_disable(ffs->func);
2958
2959         if (ffs->state == FFS_DEACTIVATED) {
2960                 ffs->state = FFS_CLOSING;
2961                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
2962                 schedule_work(&ffs->reset_work);
2963                 return -ENODEV;
2964         }
2965
2966         if (ffs->state != FFS_ACTIVE)
2967                 return -ENODEV;
2968
2969         if (alt == (unsigned)-1) {
2970                 ffs->func = NULL;
2971                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2972                 return 0;
2973         }
2974
2975         ffs->func = func;
2976         ret = ffs_func_eps_enable(func);
2977         if (likely(ret >= 0))
2978                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2979         return ret;
2980 }
2981
2982 static void ffs_func_disable(struct usb_function *f)
2983 {
2984         ffs_func_set_alt(f, 0, (unsigned)-1);
2985 }
2986
2987 static int ffs_func_setup(struct usb_function *f,
2988                           const struct usb_ctrlrequest *creq)
2989 {
2990         struct ffs_function *func = ffs_func_from_usb(f);
2991         struct ffs_data *ffs = func->ffs;
2992         unsigned long flags;
2993         int ret;
2994
2995         ENTER();
2996
2997         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2998         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2999         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3000         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3001         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3002
3003         /*
3004          * Most requests directed to interface go through here
3005          * (notable exceptions are set/get interface) so we need to
3006          * handle them.  All other either handled by composite or
3007          * passed to usb_configuration->setup() (if one is set).  No
3008          * matter, we will handle requests directed to endpoint here
3009          * as well (as it's straightforward) but what to do with any
3010          * other request?
3011          */
3012         if (ffs->state != FFS_ACTIVE)
3013                 return -ENODEV;
3014
3015         switch (creq->bRequestType & USB_RECIP_MASK) {
3016         case USB_RECIP_INTERFACE:
3017                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3018                 if (unlikely(ret < 0))
3019                         return ret;
3020                 break;
3021
3022         case USB_RECIP_ENDPOINT:
3023                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3024                 if (unlikely(ret < 0))
3025                         return ret;
3026                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3027                         ret = func->ffs->eps_addrmap[ret];
3028                 break;
3029
3030         default:
3031                 return -EOPNOTSUPP;
3032         }
3033
3034         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3035         ffs->ev.setup = *creq;
3036         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3037         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3038         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3039
3040         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3041 }
3042
3043 static void ffs_func_suspend(struct usb_function *f)
3044 {
3045         ENTER();
3046         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3047 }
3048
3049 static void ffs_func_resume(struct usb_function *f)
3050 {
3051         ENTER();
3052         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3053 }
3054
3055
3056 /* Endpoint and interface numbers reverse mapping ***************************/
3057
3058 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3059 {
3060         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3061         return num ? num : -EDOM;
3062 }
3063
3064 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3065 {
3066         short *nums = func->interfaces_nums;
3067         unsigned count = func->ffs->interfaces_count;
3068
3069         for (; count; --count, ++nums) {
3070                 if (*nums >= 0 && *nums == intf)
3071                         return nums - func->interfaces_nums;
3072         }
3073
3074         return -EDOM;
3075 }
3076
3077
3078 /* Devices management *******************************************************/
3079
3080 static LIST_HEAD(ffs_devices);
3081
3082 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3083 {
3084         struct ffs_dev *dev;
3085
3086         list_for_each_entry(dev, &ffs_devices, entry) {
3087                 if (!dev->name || !name)
3088                         continue;
3089                 if (strcmp(dev->name, name) == 0)
3090                         return dev;
3091         }
3092
3093         return NULL;
3094 }
3095
3096 /*
3097  * ffs_lock must be taken by the caller of this function
3098  */
3099 static struct ffs_dev *_ffs_get_single_dev(void)
3100 {
3101         struct ffs_dev *dev;
3102
3103         if (list_is_singular(&ffs_devices)) {
3104                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3105                 if (dev->single)
3106                         return dev;
3107         }
3108
3109         return NULL;
3110 }
3111
3112 /*
3113  * ffs_lock must be taken by the caller of this function
3114  */
3115 static struct ffs_dev *_ffs_find_dev(const char *name)
3116 {
3117         struct ffs_dev *dev;
3118
3119         dev = _ffs_get_single_dev();
3120         if (dev)
3121                 return dev;
3122
3123         return _ffs_do_find_dev(name);
3124 }
3125
3126 /* Configfs support *********************************************************/
3127
3128 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3129 {
3130         return container_of(to_config_group(item), struct f_fs_opts,
3131                             func_inst.group);
3132 }
3133
3134 static void ffs_attr_release(struct config_item *item)
3135 {
3136         struct f_fs_opts *opts = to_ffs_opts(item);
3137
3138         usb_put_function_instance(&opts->func_inst);
3139 }
3140
3141 static struct configfs_item_operations ffs_item_ops = {
3142         .release        = ffs_attr_release,
3143 };
3144
3145 static struct config_item_type ffs_func_type = {
3146         .ct_item_ops    = &ffs_item_ops,
3147         .ct_owner       = THIS_MODULE,
3148 };
3149
3150
3151 /* Function registration interface ******************************************/
3152
3153 static void ffs_free_inst(struct usb_function_instance *f)
3154 {
3155         struct f_fs_opts *opts;
3156
3157         opts = to_f_fs_opts(f);
3158         ffs_dev_lock();
3159         _ffs_free_dev(opts->dev);
3160         ffs_dev_unlock();
3161         kfree(opts);
3162 }
3163
3164 #define MAX_INST_NAME_LEN       40
3165
3166 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3167 {
3168         struct f_fs_opts *opts;
3169         char *ptr;
3170         const char *tmp;
3171         int name_len, ret;
3172
3173         name_len = strlen(name) + 1;
3174         if (name_len > MAX_INST_NAME_LEN)
3175                 return -ENAMETOOLONG;
3176
3177         ptr = kstrndup(name, name_len, GFP_KERNEL);
3178         if (!ptr)
3179                 return -ENOMEM;
3180
3181         opts = to_f_fs_opts(fi);
3182         tmp = NULL;
3183
3184         ffs_dev_lock();
3185
3186         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
3187         ret = _ffs_name_dev(opts->dev, ptr);
3188         if (ret) {
3189                 kfree(ptr);
3190                 ffs_dev_unlock();
3191                 return ret;
3192         }
3193         opts->dev->name_allocated = true;
3194
3195         ffs_dev_unlock();
3196
3197         kfree(tmp);
3198
3199         return 0;
3200 }
3201
3202 static struct usb_function_instance *ffs_alloc_inst(void)
3203 {
3204         struct f_fs_opts *opts;
3205         struct ffs_dev *dev;
3206
3207         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3208         if (!opts)
3209                 return ERR_PTR(-ENOMEM);
3210
3211         opts->func_inst.set_inst_name = ffs_set_inst_name;
3212         opts->func_inst.free_func_inst = ffs_free_inst;
3213         ffs_dev_lock();
3214         dev = _ffs_alloc_dev();
3215         ffs_dev_unlock();
3216         if (IS_ERR(dev)) {
3217                 kfree(opts);
3218                 return ERR_CAST(dev);
3219         }
3220         opts->dev = dev;
3221         dev->opts = opts;
3222
3223         config_group_init_type_name(&opts->func_inst.group, "",
3224                                     &ffs_func_type);
3225         return &opts->func_inst;
3226 }
3227
3228 static void ffs_free(struct usb_function *f)
3229 {
3230         kfree(ffs_func_from_usb(f));
3231 }
3232
3233 static void ffs_func_unbind(struct usb_configuration *c,
3234                             struct usb_function *f)
3235 {
3236         struct ffs_function *func = ffs_func_from_usb(f);
3237         struct ffs_data *ffs = func->ffs;
3238         struct f_fs_opts *opts =
3239                 container_of(f->fi, struct f_fs_opts, func_inst);
3240         struct ffs_ep *ep = func->eps;
3241         unsigned count = ffs->eps_count;
3242         unsigned long flags;
3243
3244         ENTER();
3245         if (ffs->func == func) {
3246                 ffs_func_eps_disable(func);
3247                 ffs->func = NULL;
3248         }
3249
3250         if (!--opts->refcnt)
3251                 functionfs_unbind(ffs);
3252
3253         /* cleanup after autoconfig */
3254         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3255         do {
3256                 if (ep->ep && ep->req)
3257                         usb_ep_free_request(ep->ep, ep->req);
3258                 ep->req = NULL;
3259                 ++ep;
3260         } while (--count);
3261         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3262         kfree(func->eps);
3263         func->eps = NULL;
3264         /*
3265          * eps, descriptors and interfaces_nums are allocated in the
3266          * same chunk so only one free is required.
3267          */
3268         func->function.fs_descriptors = NULL;
3269         func->function.hs_descriptors = NULL;
3270         func->function.ss_descriptors = NULL;
3271         func->interfaces_nums = NULL;
3272
3273         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3274 }
3275
3276 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3277 {
3278         struct ffs_function *func;
3279
3280         ENTER();
3281
3282         func = kzalloc(sizeof(*func), GFP_KERNEL);
3283         if (unlikely(!func))
3284                 return ERR_PTR(-ENOMEM);
3285
3286         func->function.name    = "Function FS Gadget";
3287
3288         func->function.bind    = ffs_func_bind;
3289         func->function.unbind  = ffs_func_unbind;
3290         func->function.set_alt = ffs_func_set_alt;
3291         func->function.disable = ffs_func_disable;
3292         func->function.setup   = ffs_func_setup;
3293         func->function.suspend = ffs_func_suspend;
3294         func->function.resume  = ffs_func_resume;
3295         func->function.free_func = ffs_free;
3296
3297         return &func->function;
3298 }
3299
3300 /*
3301  * ffs_lock must be taken by the caller of this function
3302  */
3303 static struct ffs_dev *_ffs_alloc_dev(void)
3304 {
3305         struct ffs_dev *dev;
3306         int ret;
3307
3308         if (_ffs_get_single_dev())
3309                         return ERR_PTR(-EBUSY);
3310
3311         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3312         if (!dev)
3313                 return ERR_PTR(-ENOMEM);
3314
3315         if (list_empty(&ffs_devices)) {
3316                 ret = functionfs_init();
3317                 if (ret) {
3318                         kfree(dev);
3319                         return ERR_PTR(ret);
3320                 }
3321         }
3322
3323         list_add(&dev->entry, &ffs_devices);
3324
3325         return dev;
3326 }
3327
3328 /*
3329  * ffs_lock must be taken by the caller of this function
3330  * The caller is responsible for "name" being available whenever f_fs needs it
3331  */
3332 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
3333 {
3334         struct ffs_dev *existing;
3335
3336         existing = _ffs_do_find_dev(name);
3337         if (existing)
3338                 return -EBUSY;
3339
3340         dev->name = name;
3341
3342         return 0;
3343 }
3344
3345 /*
3346  * The caller is responsible for "name" being available whenever f_fs needs it
3347  */
3348 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3349 {
3350         int ret;
3351
3352         ffs_dev_lock();
3353         ret = _ffs_name_dev(dev, name);
3354         ffs_dev_unlock();
3355
3356         return ret;
3357 }
3358 EXPORT_SYMBOL_GPL(ffs_name_dev);
3359
3360 int ffs_single_dev(struct ffs_dev *dev)
3361 {
3362         int ret;
3363
3364         ret = 0;
3365         ffs_dev_lock();
3366
3367         if (!list_is_singular(&ffs_devices))
3368                 ret = -EBUSY;
3369         else
3370                 dev->single = true;
3371
3372         ffs_dev_unlock();
3373         return ret;
3374 }
3375 EXPORT_SYMBOL_GPL(ffs_single_dev);
3376
3377 /*
3378  * ffs_lock must be taken by the caller of this function
3379  */
3380 static void _ffs_free_dev(struct ffs_dev *dev)
3381 {
3382         list_del(&dev->entry);
3383         if (dev->name_allocated)
3384                 kfree(dev->name);
3385         kfree(dev);
3386         if (list_empty(&ffs_devices))
3387                 functionfs_cleanup();
3388 }
3389
3390 static void *ffs_acquire_dev(const char *dev_name)
3391 {
3392         struct ffs_dev *ffs_dev;
3393
3394         ENTER();
3395         ffs_dev_lock();
3396
3397         ffs_dev = _ffs_find_dev(dev_name);
3398         if (!ffs_dev)
3399                 ffs_dev = ERR_PTR(-ENOENT);
3400         else if (ffs_dev->mounted)
3401                 ffs_dev = ERR_PTR(-EBUSY);
3402         else if (ffs_dev->ffs_acquire_dev_callback &&
3403             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3404                 ffs_dev = ERR_PTR(-ENOENT);
3405         else
3406                 ffs_dev->mounted = true;
3407
3408         ffs_dev_unlock();
3409         return ffs_dev;
3410 }
3411
3412 static void ffs_release_dev(struct ffs_data *ffs_data)
3413 {
3414         struct ffs_dev *ffs_dev;
3415
3416         ENTER();
3417         ffs_dev_lock();
3418
3419         ffs_dev = ffs_data->private_data;
3420         if (ffs_dev) {
3421                 ffs_dev->mounted = false;
3422
3423                 if (ffs_dev->ffs_release_dev_callback)
3424                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3425         }
3426
3427         ffs_dev_unlock();
3428 }
3429
3430 static int ffs_ready(struct ffs_data *ffs)
3431 {
3432         struct ffs_dev *ffs_obj;
3433         int ret = 0;
3434
3435         ENTER();
3436         ffs_dev_lock();
3437
3438         ffs_obj = ffs->private_data;
3439         if (!ffs_obj) {
3440                 ret = -EINVAL;
3441                 goto done;
3442         }
3443         if (WARN_ON(ffs_obj->desc_ready)) {
3444                 ret = -EBUSY;
3445                 goto done;
3446         }
3447
3448         ffs_obj->desc_ready = true;
3449         ffs_obj->ffs_data = ffs;
3450
3451         if (ffs_obj->ffs_ready_callback) {
3452                 ret = ffs_obj->ffs_ready_callback(ffs);
3453                 if (ret)
3454                         goto done;
3455         }
3456
3457         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3458 done:
3459         ffs_dev_unlock();
3460         return ret;
3461 }
3462
3463 static void ffs_closed(struct ffs_data *ffs)
3464 {
3465         struct ffs_dev *ffs_obj;
3466         struct f_fs_opts *opts;
3467         struct config_item *ci;
3468
3469         ENTER();
3470         ffs_dev_lock();
3471
3472         ffs_obj = ffs->private_data;
3473         if (!ffs_obj)
3474                 goto done;
3475
3476         ffs_obj->desc_ready = false;
3477
3478         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3479             ffs_obj->ffs_closed_callback)
3480                 ffs_obj->ffs_closed_callback(ffs);
3481
3482         if (ffs_obj->opts)
3483                 opts = ffs_obj->opts;
3484         else
3485                 goto done;
3486
3487         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3488             || !atomic_read(&opts->func_inst.group.cg_item.ci_kref.refcount))
3489                 goto done;
3490
3491         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3492         ffs_dev_unlock();
3493
3494         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3495                 unregister_gadget_item(ci);
3496         return;
3497 done:
3498         ffs_dev_unlock();
3499 }
3500
3501 /* Misc helper functions ****************************************************/
3502
3503 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3504 {
3505         return nonblock
3506                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3507                 : mutex_lock_interruptible(mutex);
3508 }
3509
3510 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3511 {
3512         char *data;
3513
3514         if (unlikely(!len))
3515                 return NULL;
3516
3517         data = kmalloc(len, GFP_KERNEL);
3518         if (unlikely(!data))
3519                 return ERR_PTR(-ENOMEM);
3520
3521         if (unlikely(copy_from_user(data, buf, len))) {
3522                 kfree(data);
3523                 return ERR_PTR(-EFAULT);
3524         }
3525
3526         pr_vdebug("Buffer from user space:\n");
3527         ffs_dump_mem("", data, len);
3528
3529         return data;
3530 }
3531
3532 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3533 MODULE_LICENSE("GPL");
3534 MODULE_AUTHOR("Michal Nazarewicz");