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