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 <asm/unaligned.h>
  27
  28 #include <linux/usb/composite.h>
  29 #include <linux/usb/functionfs.h>
  30
  31 #include <linux/aio.h>
  32 #include <linux/mmu_context.h>
  33 #include <linux/poll.h>
  34 #include <linux/eventfd.h>
  35
  36 #include "u_fs.h"
  37 #include "u_f.h"
  38 #include "u_os_desc.h"
  39 #include "configfs.h"
  40
  41 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  42
  43 /* Reference counter handling */
  44 static void ffs_data_get(struct ffs_data *ffs);
  45 static void ffs_data_put(struct ffs_data *ffs);
  46 /* Creates new ffs_data object. */
  47 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
  48
  49 /* Opened counter handling. */
  50 static void ffs_data_opened(struct ffs_data *ffs);
  51 static void ffs_data_closed(struct ffs_data *ffs);
  52
  53 /* Called with ffs->mutex held; take over ownership of data. */
  54 static int __must_check
  55 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  56 static int __must_check
  57 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  58
  59
  60 /* The function structure ***************************************************/
  61
  62 struct ffs_ep;
  63
  64 struct ffs_function {
  65         struct usb_configuration        *conf;
  66         struct usb_gadget               *gadget;
  67         struct ffs_data                 *ffs;
  68
  69         struct ffs_ep                   *eps;
  70         u8                              eps_revmap[16];
  71         short                           *interfaces_nums;
  72
  73         struct usb_function             function;
  74 };
  75
  76
  77 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  78 {
  79         return container_of(f, struct ffs_function, function);
  80 }
  81
  82
  83 static inline enum ffs_setup_state
  84 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  85 {
  86         return (enum ffs_setup_state)
  87                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  88 }
  89
  90
  91 static void ffs_func_eps_disable(struct ffs_function *func);
  92 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  93
  94 static int ffs_func_bind(struct usb_configuration *,
  95                          struct usb_function *);
  96 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
  97 static void ffs_func_disable(struct usb_function *);
  98 static int ffs_func_setup(struct usb_function *,
  99                           const struct usb_ctrlrequest *);
 100 static void ffs_func_suspend(struct usb_function *);
 101 static void ffs_func_resume(struct usb_function *);
 102
 103
 104 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 105 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 106
 107
 108 /* The endpoints structures *************************************************/
 109
 110 struct ffs_ep {
 111         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 112         struct usb_request              *req;   /* P: epfile->mutex */
 113
 114         /* [0]: full speed, [1]: high speed, [2]: super speed */
 115         struct usb_endpoint_descriptor  *descs[3];
 116
 117         u8                              num;
 118
 119         int                             status; /* P: epfile->mutex */
 120 };
 121
 122 struct ffs_epfile {
 123         /* Protects ep->ep and ep->req. */
 124         struct mutex                    mutex;
 125         wait_queue_head_t               wait;
 126
 127         struct ffs_data                 *ffs;
 128         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 129
 130         struct dentry                   *dentry;
 131
 132         char                            name[5];
 133
 134         unsigned char                   in;     /* P: ffs->eps_lock */
 135         unsigned char                   isoc;   /* P: ffs->eps_lock */
 136
 137         unsigned char                   _pad;
 138 };
 139
 140 /*  ffs_io_data structure ***************************************************/
 141
 142 struct ffs_io_data {
 143         bool aio;
 144         bool read;
 145
 146         struct kiocb *kiocb;
 147         const struct iovec *iovec;
 148         unsigned long nr_segs;
 149         char __user *buf;
 150         size_t len;
 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                 int i;
 653                 size_t pos = 0;
 654
 655                 /*
 656                  * Since req->length may be bigger than io_data->len (after
 657                  * being rounded up to maxpacketsize), we may end up with more
 658                  * data then user space has space for.
 659                  */
 660                 ret = min_t(int, ret, io_data->len);
 661
 662                 use_mm(io_data->mm);
 663                 for (i = 0; i < io_data->nr_segs; i++) {
 664                         size_t len = min_t(size_t, ret - pos,
 665                                         io_data->iovec[i].iov_len);
 666                         if (!len)
 667                                 break;
 668                         if (unlikely(copy_to_user(io_data->iovec[i].iov_base,
 669                                                  &io_data->buf[pos], len))) {
 670                                 ret = -EFAULT;
 671                                 break;
 672                         }
 673                         pos += len;
 674                 }
 675                 unuse_mm(io_data->mm);
 676         }
 677
 678         aio_complete(io_data->kiocb, ret, ret);
 679
 680         if (io_data->ffs->ffs_eventfd && !io_data->kiocb->ki_eventfd)
 681                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 682
 683         usb_ep_free_request(io_data->ep, io_data->req);
 684
 685         io_data->kiocb->private = NULL;
 686         if (io_data->read)
 687                 kfree(io_data->iovec);
 688         kfree(io_data->buf);
 689         kfree(io_data);
 690 }
 691
 692 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 693                                          struct usb_request *req)
 694 {
 695         struct ffs_io_data *io_data = req->context;
 696
 697         ENTER();
 698
 699         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 700         schedule_work(&io_data->work);
 701 }
 702
 703 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 704 {
 705         struct ffs_epfile *epfile = file->private_data;
 706         struct ffs_ep *ep;
 707         char *data = NULL;
 708         ssize_t ret, data_len = -EINVAL;
 709         int halt;
 710
 711         /* Are we still active? */
 712         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
 713                 ret = -ENODEV;
 714                 goto error;
 715         }
 716
 717         /* Wait for endpoint to be enabled */
 718         ep = epfile->ep;
 719         if (!ep) {
 720                 if (file->f_flags & O_NONBLOCK) {
 721                         ret = -EAGAIN;
 722                         goto error;
 723                 }
 724
 725                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
 726                 if (ret) {
 727                         ret = -EINTR;
 728                         goto error;
 729                 }
 730         }
 731
 732         /* Do we halt? */
 733         halt = (!io_data->read == !epfile->in);
 734         if (halt && epfile->isoc) {
 735                 ret = -EINVAL;
 736                 goto error;
 737         }
 738
 739         /* Allocate & copy */
 740         if (!halt) {
 741                 /*
 742                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 743                  * before the waiting completes, so do not assign to 'gadget' earlier
 744                  */
 745                 struct usb_gadget *gadget = epfile->ffs->gadget;
 746
 747                 spin_lock_irq(&epfile->ffs->eps_lock);
 748                 /* In the meantime, endpoint got disabled or changed. */
 749                 if (epfile->ep != ep) {
 750                         spin_unlock_irq(&epfile->ffs->eps_lock);
 751                         return -ESHUTDOWN;
 752                 }
 753                 /*
 754                  * Controller may require buffer size to be aligned to
 755                  * maxpacketsize of an out endpoint.
 756                  */
 757                 data_len = io_data->read ?
 758                            usb_ep_align_maybe(gadget, ep->ep, io_data->len) :
 759                            io_data->len;
 760                 spin_unlock_irq(&epfile->ffs->eps_lock);
 761
 762                 data = kmalloc(data_len, GFP_KERNEL);
 763                 if (unlikely(!data))
 764                         return -ENOMEM;
 765                 if (io_data->aio && !io_data->read) {
 766                         int i;
 767                         size_t pos = 0;
 768                         for (i = 0; i < io_data->nr_segs; i++) {
 769                                 if (unlikely(copy_from_user(&data[pos],
 770                                              io_data->iovec[i].iov_base,
 771                                              io_data->iovec[i].iov_len))) {
 772                                         ret = -EFAULT;
 773                                         goto error;
 774                                 }
 775                                 pos += io_data->iovec[i].iov_len;
 776                         }
 777                 } else {
 778                         if (!io_data->read &&
 779                             unlikely(__copy_from_user(data, io_data->buf,
 780                                                       io_data->len))) {
 781                                 ret = -EFAULT;
 782                                 goto error;
 783                         }
 784                 }
 785         }
 786
 787         /* We will be using request */
 788         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 789         if (unlikely(ret))
 790                 goto error;
 791
 792         spin_lock_irq(&epfile->ffs->eps_lock);
 793
 794         if (epfile->ep != ep) {
 795                 /* In the meantime, endpoint got disabled or changed. */
 796                 ret = -ESHUTDOWN;
 797                 spin_unlock_irq(&epfile->ffs->eps_lock);
 798         } else if (halt) {
 799                 /* Halt */
 800                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 801                         usb_ep_set_halt(ep->ep);
 802                 spin_unlock_irq(&epfile->ffs->eps_lock);
 803                 ret = -EBADMSG;
 804         } else {
 805                 /* Fire the request */
 806                 struct usb_request *req;
 807
 808                 /*
 809                  * Sanity Check: even though data_len can't be used
 810                  * uninitialized at the time I write this comment, some
 811                  * compilers complain about this situation.
 812                  * In order to keep the code clean from warnings, data_len is
 813                  * being initialized to -EINVAL during its declaration, which
 814                  * means we can't rely on compiler anymore to warn no future
 815                  * changes won't result in data_len being used uninitialized.
 816                  * For such reason, we're adding this redundant sanity check
 817                  * here.
 818                  */
 819                 if (unlikely(data_len == -EINVAL)) {
 820                         WARN(1, "%s: data_len == -EINVAL\n", __func__);
 821                         ret = -EINVAL;
 822                         goto error_lock;
 823                 }
 824
 825                 if (io_data->aio) {
 826                         req = usb_ep_alloc_request(ep->ep, GFP_KERNEL);
 827                         if (unlikely(!req))
 828                                 goto error_lock;
 829
 830                         req->buf      = data;
 831                         req->length   = data_len;
 832
 833                         io_data->buf = data;
 834                         io_data->ep = ep->ep;
 835                         io_data->req = req;
 836                         io_data->ffs = epfile->ffs;
 837
 838                         req->context  = io_data;
 839                         req->complete = ffs_epfile_async_io_complete;
 840
 841                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 842                         if (unlikely(ret)) {
 843                                 usb_ep_free_request(ep->ep, req);
 844                                 goto error_lock;
 845                         }
 846                         ret = -EIOCBQUEUED;
 847
 848                         spin_unlock_irq(&epfile->ffs->eps_lock);
 849                 } else {
 850                         DECLARE_COMPLETION_ONSTACK(done);
 851
 852                         req = ep->req;
 853                         req->buf      = data;
 854                         req->length   = data_len;
 855
 856                         req->context  = &done;
 857                         req->complete = ffs_epfile_io_complete;
 858
 859                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 860
 861                         spin_unlock_irq(&epfile->ffs->eps_lock);
 862
 863                         if (unlikely(ret < 0)) {
 864                                 /* nop */
 865                         } else if (unlikely(
 866                                    wait_for_completion_interruptible(&done))) {
 867                                 ret = -EINTR;
 868                                 usb_ep_dequeue(ep->ep, req);
 869                         } else {
 870                                 /*
 871                                  * XXX We may end up silently droping data
 872                                  * here.  Since data_len (i.e. req->length) may
 873                                  * be bigger than len (after being rounded up
 874                                  * to maxpacketsize), we may end up with more
 875                                  * data then user space has space for.
 876                                  */
 877                                 ret = ep->status;
 878                                 if (io_data->read && ret > 0) {
 879                                         ret = min_t(size_t, ret, io_data->len);
 880
 881                                         if (unlikely(copy_to_user(io_data->buf,
 882                                                 data, ret)))
 883                                                 ret = -EFAULT;
 884                                 }
 885                         }
 886                         kfree(data);
 887                 }
 888         }
 889
 890         mutex_unlock(&epfile->mutex);
 891         return ret;
 892
 893 error_lock:
 894         spin_unlock_irq(&epfile->ffs->eps_lock);
 895         mutex_unlock(&epfile->mutex);
 896 error:
 897         kfree(data);
 898         return ret;
 899 }
 900
 901 static ssize_t
 902 ffs_epfile_write(struct file *file, const char __user *buf, size_t len,
 903                  loff_t *ptr)
 904 {
 905         struct ffs_io_data io_data;
 906
 907         ENTER();
 908
 909         io_data.aio = false;
 910         io_data.read = false;
 911         io_data.buf = (char * __user)buf;
 912         io_data.len = len;
 913
 914         return ffs_epfile_io(file, &io_data);
 915 }
 916
 917 static ssize_t
 918 ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr)
 919 {
 920         struct ffs_io_data io_data;
 921
 922         ENTER();
 923
 924         io_data.aio = false;
 925         io_data.read = true;
 926         io_data.buf = buf;
 927         io_data.len = len;
 928
 929         return ffs_epfile_io(file, &io_data);
 930 }
 931
 932 static int
 933 ffs_epfile_open(struct inode *inode, struct file *file)
 934 {
 935         struct ffs_epfile *epfile = inode->i_private;
 936
 937         ENTER();
 938
 939         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 940                 return -ENODEV;
 941
 942         file->private_data = epfile;
 943         ffs_data_opened(epfile->ffs);
 944
 945         return 0;
 946 }
 947
 948 static int ffs_aio_cancel(struct kiocb *kiocb)
 949 {
 950         struct ffs_io_data *io_data = kiocb->private;
 951         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
 952         int value;
 953
 954         ENTER();
 955
 956         spin_lock_irq(&epfile->ffs->eps_lock);
 957
 958         if (likely(io_data && io_data->ep && io_data->req))
 959                 value = usb_ep_dequeue(io_data->ep, io_data->req);
 960         else
 961                 value = -EINVAL;
 962
 963         spin_unlock_irq(&epfile->ffs->eps_lock);
 964
 965         return value;
 966 }
 967
 968 static ssize_t ffs_epfile_aio_write(struct kiocb *kiocb,
 969                                     const struct iovec *iovec,
 970                                     unsigned long nr_segs, loff_t loff)
 971 {
 972         struct ffs_io_data *io_data;
 973
 974         ENTER();
 975
 976         io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
 977         if (unlikely(!io_data))
 978                 return -ENOMEM;
 979
 980         io_data->aio = true;
 981         io_data->read = false;
 982         io_data->kiocb = kiocb;
 983         io_data->iovec = iovec;
 984         io_data->nr_segs = nr_segs;
 985         io_data->len = kiocb->ki_nbytes;
 986         io_data->mm = current->mm;
 987
 988         kiocb->private = io_data;
 989
 990         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 991
 992         return ffs_epfile_io(kiocb->ki_filp, io_data);
 993 }
 994
 995 static ssize_t ffs_epfile_aio_read(struct kiocb *kiocb,
 996                                    const struct iovec *iovec,
 997                                    unsigned long nr_segs, loff_t loff)
 998 {
 999         struct ffs_io_data *io_data;
1000         struct iovec *iovec_copy;
1001
1002         ENTER();
1003
1004         iovec_copy = kmalloc_array(nr_segs, sizeof(*iovec_copy), GFP_KERNEL);
1005         if (unlikely(!iovec_copy))
1006                 return -ENOMEM;
1007
1008         memcpy(iovec_copy, iovec, sizeof(struct iovec)*nr_segs);
1009
1010         io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
1011         if (unlikely(!io_data)) {
1012                 kfree(iovec_copy);
1013                 return -ENOMEM;
1014         }
1015
1016         io_data->aio = true;
1017         io_data->read = true;
1018         io_data->kiocb = kiocb;
1019         io_data->iovec = iovec_copy;
1020         io_data->nr_segs = nr_segs;
1021         io_data->len = kiocb->ki_nbytes;
1022         io_data->mm = current->mm;
1023
1024         kiocb->private = io_data;
1025
1026         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1027
1028         return ffs_epfile_io(kiocb->ki_filp, io_data);
1029 }
1030
1031 static int
1032 ffs_epfile_release(struct inode *inode, struct file *file)
1033 {
1034         struct ffs_epfile *epfile = inode->i_private;
1035
1036         ENTER();
1037
1038         ffs_data_closed(epfile->ffs);
1039
1040         return 0;
1041 }
1042
1043 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1044                              unsigned long value)
1045 {
1046         struct ffs_epfile *epfile = file->private_data;
1047         int ret;
1048
1049         ENTER();
1050
1051         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1052                 return -ENODEV;
1053
1054         spin_lock_irq(&epfile->ffs->eps_lock);
1055         if (likely(epfile->ep)) {
1056                 switch (code) {
1057                 case FUNCTIONFS_FIFO_STATUS:
1058                         ret = usb_ep_fifo_status(epfile->ep->ep);
1059                         break;
1060                 case FUNCTIONFS_FIFO_FLUSH:
1061                         usb_ep_fifo_flush(epfile->ep->ep);
1062                         ret = 0;
1063                         break;
1064                 case FUNCTIONFS_CLEAR_HALT:
1065                         ret = usb_ep_clear_halt(epfile->ep->ep);
1066                         break;
1067                 case FUNCTIONFS_ENDPOINT_REVMAP:
1068                         ret = epfile->ep->num;
1069                         break;
1070                 case FUNCTIONFS_ENDPOINT_DESC:
1071                 {
1072                         int desc_idx;
1073                         struct usb_endpoint_descriptor *desc;
1074
1075                         switch (epfile->ffs->gadget->speed) {
1076                         case USB_SPEED_SUPER:
1077                                 desc_idx = 2;
1078                                 break;
1079                         case USB_SPEED_HIGH:
1080                                 desc_idx = 1;
1081                                 break;
1082                         default:
1083                                 desc_idx = 0;
1084                         }
1085                         desc = epfile->ep->descs[desc_idx];
1086
1087                         spin_unlock_irq(&epfile->ffs->eps_lock);
1088                         ret = copy_to_user((void *)value, desc, sizeof(*desc));
1089                         if (ret)
1090                                 ret = -EFAULT;
1091                         return ret;
1092                 }
1093                 default:
1094                         ret = -ENOTTY;
1095                 }
1096         } else {
1097                 ret = -ENODEV;
1098         }
1099         spin_unlock_irq(&epfile->ffs->eps_lock);
1100
1101         return ret;
1102 }
1103
1104 static const struct file_operations ffs_epfile_operations = {
1105         .llseek =       no_llseek,
1106
1107         .open =         ffs_epfile_open,
1108         .write =        ffs_epfile_write,
1109         .read =         ffs_epfile_read,
1110         .aio_write =    ffs_epfile_aio_write,
1111         .aio_read =     ffs_epfile_aio_read,
1112         .release =      ffs_epfile_release,
1113         .unlocked_ioctl =       ffs_epfile_ioctl,
1114 };
1115
1116
1117 /* File system and super block operations ***********************************/
1118
1119 /*
1120  * Mounting the file system creates a controller file, used first for
1121  * function configuration then later for event monitoring.
1122  */
1123
1124 static struct inode *__must_check
1125 ffs_sb_make_inode(struct super_block *sb, void *data,
1126                   const struct file_operations *fops,
1127                   const struct inode_operations *iops,
1128                   struct ffs_file_perms *perms)
1129 {
1130         struct inode *inode;
1131
1132         ENTER();
1133
1134         inode = new_inode(sb);
1135
1136         if (likely(inode)) {
1137                 struct timespec current_time = CURRENT_TIME;
1138
1139                 inode->i_ino     = get_next_ino();
1140                 inode->i_mode    = perms->mode;
1141                 inode->i_uid     = perms->uid;
1142                 inode->i_gid     = perms->gid;
1143                 inode->i_atime   = current_time;
1144                 inode->i_mtime   = current_time;
1145                 inode->i_ctime   = current_time;
1146                 inode->i_private = data;
1147                 if (fops)
1148                         inode->i_fop = fops;
1149                 if (iops)
1150                         inode->i_op  = iops;
1151         }
1152
1153         return inode;
1154 }
1155
1156 /* Create "regular" file */
1157 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1158                                         const char *name, void *data,
1159                                         const struct file_operations *fops)
1160 {
1161         struct ffs_data *ffs = sb->s_fs_info;
1162         struct dentry   *dentry;
1163         struct inode    *inode;
1164
1165         ENTER();
1166
1167         dentry = d_alloc_name(sb->s_root, name);
1168         if (unlikely(!dentry))
1169                 return NULL;
1170
1171         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1172         if (unlikely(!inode)) {
1173                 dput(dentry);
1174                 return NULL;
1175         }
1176
1177         d_add(dentry, inode);
1178         return dentry;
1179 }
1180
1181 /* Super block */
1182 static const struct super_operations ffs_sb_operations = {
1183         .statfs =       simple_statfs,
1184         .drop_inode =   generic_delete_inode,
1185 };
1186
1187 struct ffs_sb_fill_data {
1188         struct ffs_file_perms perms;
1189         umode_t root_mode;
1190         const char *dev_name;
1191         bool no_disconnect;
1192         struct ffs_data *ffs_data;
1193 };
1194
1195 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1196 {
1197         struct ffs_sb_fill_data *data = _data;
1198         struct inode    *inode;
1199         struct ffs_data *ffs = data->ffs_data;
1200
1201         ENTER();
1202
1203         ffs->sb              = sb;
1204         data->ffs_data       = NULL;
1205         sb->s_fs_info        = ffs;
1206         sb->s_blocksize      = PAGE_CACHE_SIZE;
1207         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1208         sb->s_magic          = FUNCTIONFS_MAGIC;
1209         sb->s_op             = &ffs_sb_operations;
1210         sb->s_time_gran      = 1;
1211
1212         /* Root inode */
1213         data->perms.mode = data->root_mode;
1214         inode = ffs_sb_make_inode(sb, NULL,
1215                                   &simple_dir_operations,
1216                                   &simple_dir_inode_operations,
1217                                   &data->perms);
1218         sb->s_root = d_make_root(inode);
1219         if (unlikely(!sb->s_root))
1220                 return -ENOMEM;
1221
1222         /* EP0 file */
1223         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1224                                          &ffs_ep0_operations)))
1225                 return -ENOMEM;
1226
1227         return 0;
1228 }
1229
1230 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1231 {
1232         ENTER();
1233
1234         if (!opts || !*opts)
1235                 return 0;
1236
1237         for (;;) {
1238                 unsigned long value;
1239                 char *eq, *comma;
1240
1241                 /* Option limit */
1242                 comma = strchr(opts, ',');
1243                 if (comma)
1244                         *comma = 0;
1245
1246                 /* Value limit */
1247                 eq = strchr(opts, '=');
1248                 if (unlikely(!eq)) {
1249                         pr_err("'=' missing in %s\n", opts);
1250                         return -EINVAL;
1251                 }
1252                 *eq = 0;
1253
1254                 /* Parse value */
1255                 if (kstrtoul(eq + 1, 0, &value)) {
1256                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1257                         return -EINVAL;
1258                 }
1259
1260                 /* Interpret option */
1261                 switch (eq - opts) {
1262                 case 13:
1263                         if (!memcmp(opts, "no_disconnect", 13))
1264                                 data->no_disconnect = !!value;
1265                         else
1266                                 goto invalid;
1267                         break;
1268                 case 5:
1269                         if (!memcmp(opts, "rmode", 5))
1270                                 data->root_mode  = (value & 0555) | S_IFDIR;
1271                         else if (!memcmp(opts, "fmode", 5))
1272                                 data->perms.mode = (value & 0666) | S_IFREG;
1273                         else
1274                                 goto invalid;
1275                         break;
1276
1277                 case 4:
1278                         if (!memcmp(opts, "mode", 4)) {
1279                                 data->root_mode  = (value & 0555) | S_IFDIR;
1280                                 data->perms.mode = (value & 0666) | S_IFREG;
1281                         } else {
1282                                 goto invalid;
1283                         }
1284                         break;
1285
1286                 case 3:
1287                         if (!memcmp(opts, "uid", 3)) {
1288                                 data->perms.uid = make_kuid(current_user_ns(), value);
1289                                 if (!uid_valid(data->perms.uid)) {
1290                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1291                                         return -EINVAL;
1292                                 }
1293                         } else if (!memcmp(opts, "gid", 3)) {
1294                                 data->perms.gid = make_kgid(current_user_ns(), value);
1295                                 if (!gid_valid(data->perms.gid)) {
1296                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1297                                         return -EINVAL;
1298                                 }
1299                         } else {
1300                                 goto invalid;
1301                         }
1302                         break;
1303
1304                 default:
1305 invalid:
1306                         pr_err("%s: invalid option\n", opts);
1307                         return -EINVAL;
1308                 }
1309
1310                 /* Next iteration */
1311                 if (!comma)
1312                         break;
1313                 opts = comma + 1;
1314         }
1315
1316         return 0;
1317 }
1318
1319 /* "mount -t functionfs dev_name /dev/function" ends up here */
1320
1321 static struct dentry *
1322 ffs_fs_mount(struct file_system_type *t, int flags,
1323               const char *dev_name, void *opts)
1324 {
1325         struct ffs_sb_fill_data data = {
1326                 .perms = {
1327                         .mode = S_IFREG | 0600,
1328                         .uid = GLOBAL_ROOT_UID,
1329                         .gid = GLOBAL_ROOT_GID,
1330                 },
1331                 .root_mode = S_IFDIR | 0500,
1332                 .no_disconnect = false,
1333         };
1334         struct dentry *rv;
1335         int ret;
1336         void *ffs_dev;
1337         struct ffs_data *ffs;
1338
1339         ENTER();
1340
1341         ret = ffs_fs_parse_opts(&data, opts);
1342         if (unlikely(ret < 0))
1343                 return ERR_PTR(ret);
1344
1345         ffs = ffs_data_new();
1346         if (unlikely(!ffs))
1347                 return ERR_PTR(-ENOMEM);
1348         ffs->file_perms = data.perms;
1349         ffs->no_disconnect = data.no_disconnect;
1350
1351         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1352         if (unlikely(!ffs->dev_name)) {
1353                 ffs_data_put(ffs);
1354                 return ERR_PTR(-ENOMEM);
1355         }
1356
1357         ffs_dev = ffs_acquire_dev(dev_name);
1358         if (IS_ERR(ffs_dev)) {
1359                 ffs_data_put(ffs);
1360                 return ERR_CAST(ffs_dev);
1361         }
1362         ffs->private_data = ffs_dev;
1363         data.ffs_data = ffs;
1364
1365         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1366         if (IS_ERR(rv) && data.ffs_data) {
1367                 ffs_release_dev(data.ffs_data);
1368                 ffs_data_put(data.ffs_data);
1369         }
1370         return rv;
1371 }
1372
1373 static void
1374 ffs_fs_kill_sb(struct super_block *sb)
1375 {
1376         ENTER();
1377
1378         kill_litter_super(sb);
1379         if (sb->s_fs_info) {
1380                 ffs_release_dev(sb->s_fs_info);
1381                 ffs_data_closed(sb->s_fs_info);
1382                 ffs_data_put(sb->s_fs_info);
1383         }
1384 }
1385
1386 static struct file_system_type ffs_fs_type = {
1387         .owner          = THIS_MODULE,
1388         .name           = "functionfs",
1389         .mount          = ffs_fs_mount,
1390         .kill_sb        = ffs_fs_kill_sb,
1391 };
1392 MODULE_ALIAS_FS("functionfs");
1393
1394
1395 /* Driver's main init/cleanup functions *************************************/
1396
1397 static int functionfs_init(void)
1398 {
1399         int ret;
1400
1401         ENTER();
1402
1403         ret = register_filesystem(&ffs_fs_type);
1404         if (likely(!ret))
1405                 pr_info("file system registered\n");
1406         else
1407                 pr_err("failed registering file system (%d)\n", ret);
1408
1409         return ret;
1410 }
1411
1412 static void functionfs_cleanup(void)
1413 {
1414         ENTER();
1415
1416         pr_info("unloading\n");
1417         unregister_filesystem(&ffs_fs_type);
1418 }
1419
1420
1421 /* ffs_data and ffs_function construction and destruction code **************/
1422
1423 static void ffs_data_clear(struct ffs_data *ffs);
1424 static void ffs_data_reset(struct ffs_data *ffs);
1425
1426 static void ffs_data_get(struct ffs_data *ffs)
1427 {
1428         ENTER();
1429
1430         atomic_inc(&ffs->ref);
1431 }
1432
1433 static void ffs_data_opened(struct ffs_data *ffs)
1434 {
1435         ENTER();
1436
1437         atomic_inc(&ffs->ref);
1438         if (atomic_add_return(1, &ffs->opened) == 1 &&
1439                         ffs->state == FFS_DEACTIVATED) {
1440                 ffs->state = FFS_CLOSING;
1441                 ffs_data_reset(ffs);
1442         }
1443 }
1444
1445 static void ffs_data_put(struct ffs_data *ffs)
1446 {
1447         ENTER();
1448
1449         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1450                 pr_info("%s(): freeing\n", __func__);
1451                 ffs_data_clear(ffs);
1452                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1453                        waitqueue_active(&ffs->ep0req_completion.wait));
1454                 kfree(ffs->dev_name);
1455                 kfree(ffs);
1456         }
1457 }
1458
1459 static void ffs_data_closed(struct ffs_data *ffs)
1460 {
1461         ENTER();
1462
1463         if (atomic_dec_and_test(&ffs->opened)) {
1464                 if (ffs->no_disconnect) {
1465                         ffs->state = FFS_DEACTIVATED;
1466                         if (ffs->epfiles) {
1467                                 ffs_epfiles_destroy(ffs->epfiles,
1468                                                    ffs->eps_count);
1469                                 ffs->epfiles = NULL;
1470                         }
1471                         if (ffs->setup_state == FFS_SETUP_PENDING)
1472                                 __ffs_ep0_stall(ffs);
1473                 } else {
1474                         ffs->state = FFS_CLOSING;
1475                         ffs_data_reset(ffs);
1476                 }
1477         }
1478         if (atomic_read(&ffs->opened) < 0) {
1479                 ffs->state = FFS_CLOSING;
1480                 ffs_data_reset(ffs);
1481         }
1482
1483         ffs_data_put(ffs);
1484 }
1485
1486 static struct ffs_data *ffs_data_new(void)
1487 {
1488         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1489         if (unlikely(!ffs))
1490                 return NULL;
1491
1492         ENTER();
1493
1494         atomic_set(&ffs->ref, 1);
1495         atomic_set(&ffs->opened, 0);
1496         ffs->state = FFS_READ_DESCRIPTORS;
1497         mutex_init(&ffs->mutex);
1498         spin_lock_init(&ffs->eps_lock);
1499         init_waitqueue_head(&ffs->ev.waitq);
1500         init_completion(&ffs->ep0req_completion);
1501
1502         /* XXX REVISIT need to update it in some places, or do we? */
1503         ffs->ev.can_stall = 1;
1504
1505         return ffs;
1506 }
1507
1508 static void ffs_data_clear(struct ffs_data *ffs)
1509 {
1510         ENTER();
1511
1512         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags))
1513                 ffs_closed(ffs);
1514
1515         BUG_ON(ffs->gadget);
1516
1517         if (ffs->epfiles)
1518                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1519
1520         if (ffs->ffs_eventfd)
1521                 eventfd_ctx_put(ffs->ffs_eventfd);
1522
1523         kfree(ffs->raw_descs_data);
1524         kfree(ffs->raw_strings);
1525         kfree(ffs->stringtabs);
1526 }
1527
1528 static void ffs_data_reset(struct ffs_data *ffs)
1529 {
1530         ENTER();
1531
1532         ffs_data_clear(ffs);
1533
1534         ffs->epfiles = NULL;
1535         ffs->raw_descs_data = NULL;
1536         ffs->raw_descs = NULL;
1537         ffs->raw_strings = NULL;
1538         ffs->stringtabs = NULL;
1539
1540         ffs->raw_descs_length = 0;
1541         ffs->fs_descs_count = 0;
1542         ffs->hs_descs_count = 0;
1543         ffs->ss_descs_count = 0;
1544
1545         ffs->strings_count = 0;
1546         ffs->interfaces_count = 0;
1547         ffs->eps_count = 0;
1548
1549         ffs->ev.count = 0;
1550
1551         ffs->state = FFS_READ_DESCRIPTORS;
1552         ffs->setup_state = FFS_NO_SETUP;
1553         ffs->flags = 0;
1554 }
1555
1556
1557 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1558 {
1559         struct usb_gadget_strings **lang;
1560         int first_id;
1561
1562         ENTER();
1563
1564         if (WARN_ON(ffs->state != FFS_ACTIVE
1565                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1566                 return -EBADFD;
1567
1568         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1569         if (unlikely(first_id < 0))
1570                 return first_id;
1571
1572         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1573         if (unlikely(!ffs->ep0req))
1574                 return -ENOMEM;
1575         ffs->ep0req->complete = ffs_ep0_complete;
1576         ffs->ep0req->context = ffs;
1577
1578         lang = ffs->stringtabs;
1579         if (lang) {
1580                 for (; *lang; ++lang) {
1581                         struct usb_string *str = (*lang)->strings;
1582                         int id = first_id;
1583                         for (; str->s; ++id, ++str)
1584                                 str->id = id;
1585                 }
1586         }
1587
1588         ffs->gadget = cdev->gadget;
1589         ffs_data_get(ffs);
1590         return 0;
1591 }
1592
1593 static void functionfs_unbind(struct ffs_data *ffs)
1594 {
1595         ENTER();
1596
1597         if (!WARN_ON(!ffs->gadget)) {
1598                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1599                 ffs->ep0req = NULL;
1600                 ffs->gadget = NULL;
1601                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1602                 ffs_data_put(ffs);
1603         }
1604 }
1605
1606 static int ffs_epfiles_create(struct ffs_data *ffs)
1607 {
1608         struct ffs_epfile *epfile, *epfiles;
1609         unsigned i, count;
1610
1611         ENTER();
1612
1613         count = ffs->eps_count;
1614         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1615         if (!epfiles)
1616                 return -ENOMEM;
1617
1618         epfile = epfiles;
1619         for (i = 1; i <= count; ++i, ++epfile) {
1620                 epfile->ffs = ffs;
1621                 mutex_init(&epfile->mutex);
1622                 init_waitqueue_head(&epfile->wait);
1623                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1624                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1625                 else
1626                         sprintf(epfile->name, "ep%u", i);
1627                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1628                                                  epfile,
1629                                                  &ffs_epfile_operations);
1630                 if (unlikely(!epfile->dentry)) {
1631                         ffs_epfiles_destroy(epfiles, i - 1);
1632                         return -ENOMEM;
1633                 }
1634         }
1635
1636         ffs->epfiles = epfiles;
1637         return 0;
1638 }
1639
1640 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1641 {
1642         struct ffs_epfile *epfile = epfiles;
1643
1644         ENTER();
1645
1646         for (; count; --count, ++epfile) {
1647                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1648                        waitqueue_active(&epfile->wait));
1649                 if (epfile->dentry) {
1650                         d_delete(epfile->dentry);
1651                         dput(epfile->dentry);
1652                         epfile->dentry = NULL;
1653                 }
1654         }
1655
1656         kfree(epfiles);
1657 }
1658
1659 static void ffs_func_eps_disable(struct ffs_function *func)
1660 {
1661         struct ffs_ep *ep         = func->eps;
1662         struct ffs_epfile *epfile = func->ffs->epfiles;
1663         unsigned count            = func->ffs->eps_count;
1664         unsigned long flags;
1665
1666         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1667         do {
1668                 /* pending requests get nuked */
1669                 if (likely(ep->ep))
1670                         usb_ep_disable(ep->ep);
1671                 ++ep;
1672
1673                 if (epfile) {
1674                         epfile->ep = NULL;
1675                         ++epfile;
1676                 }
1677         } while (--count);
1678         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1679 }
1680
1681 static int ffs_func_eps_enable(struct ffs_function *func)
1682 {
1683         struct ffs_data *ffs      = func->ffs;
1684         struct ffs_ep *ep         = func->eps;
1685         struct ffs_epfile *epfile = ffs->epfiles;
1686         unsigned count            = ffs->eps_count;
1687         unsigned long flags;
1688         int ret = 0;
1689
1690         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1691         do {
1692                 struct usb_endpoint_descriptor *ds;
1693                 int desc_idx;
1694
1695                 if (ffs->gadget->speed == USB_SPEED_SUPER)
1696                         desc_idx = 2;
1697                 else if (ffs->gadget->speed == USB_SPEED_HIGH)
1698                         desc_idx = 1;
1699                 else
1700                         desc_idx = 0;
1701
1702                 /* fall-back to lower speed if desc missing for current speed */
1703                 do {
1704                         ds = ep->descs[desc_idx];
1705                 } while (!ds && --desc_idx >= 0);
1706
1707                 if (!ds) {
1708                         ret = -EINVAL;
1709                         break;
1710                 }
1711
1712                 ep->ep->driver_data = ep;
1713                 ep->ep->desc = ds;
1714                 ret = usb_ep_enable(ep->ep);
1715                 if (likely(!ret)) {
1716                         epfile->ep = ep;
1717                         epfile->in = usb_endpoint_dir_in(ds);
1718                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1719                 } else {
1720                         break;
1721                 }
1722
1723                 wake_up(&epfile->wait);
1724
1725                 ++ep;
1726                 ++epfile;
1727         } while (--count);
1728         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1729
1730         return ret;
1731 }
1732
1733
1734 /* Parsing and building descriptors and strings *****************************/
1735
1736 /*
1737  * This validates if data pointed by data is a valid USB descriptor as
1738  * well as record how many interfaces, endpoints and strings are
1739  * required by given configuration.  Returns address after the
1740  * descriptor or NULL if data is invalid.
1741  */
1742
1743 enum ffs_entity_type {
1744         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1745 };
1746
1747 enum ffs_os_desc_type {
1748         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1749 };
1750
1751 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1752                                    u8 *valuep,
1753                                    struct usb_descriptor_header *desc,
1754                                    void *priv);
1755
1756 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1757                                     struct usb_os_desc_header *h, void *data,
1758                                     unsigned len, void *priv);
1759
1760 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1761                                            ffs_entity_callback entity,
1762                                            void *priv)
1763 {
1764         struct usb_descriptor_header *_ds = (void *)data;
1765         u8 length;
1766         int ret;
1767
1768         ENTER();
1769
1770         /* At least two bytes are required: length and type */
1771         if (len < 2) {
1772                 pr_vdebug("descriptor too short\n");
1773                 return -EINVAL;
1774         }
1775
1776         /* If we have at least as many bytes as the descriptor takes? */
1777         length = _ds->bLength;
1778         if (len < length) {
1779                 pr_vdebug("descriptor longer then available data\n");
1780                 return -EINVAL;
1781         }
1782
1783 #define __entity_check_INTERFACE(val)  1
1784 #define __entity_check_STRING(val)     (val)
1785 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1786 #define __entity(type, val) do {                                        \
1787                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1788                 if (unlikely(!__entity_check_ ##type(val))) {           \
1789                         pr_vdebug("invalid entity's value\n");          \
1790                         return -EINVAL;                                 \
1791                 }                                                       \
1792                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1793                 if (unlikely(ret < 0)) {                                \
1794                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1795                                  (val), ret);                           \
1796                         return ret;                                     \
1797                 }                                                       \
1798         } while (0)
1799
1800         /* Parse descriptor depending on type. */
1801         switch (_ds->bDescriptorType) {
1802         case USB_DT_DEVICE:
1803         case USB_DT_CONFIG:
1804         case USB_DT_STRING:
1805         case USB_DT_DEVICE_QUALIFIER:
1806                 /* function can't have any of those */
1807                 pr_vdebug("descriptor reserved for gadget: %d\n",
1808                       _ds->bDescriptorType);
1809                 return -EINVAL;
1810
1811         case USB_DT_INTERFACE: {
1812                 struct usb_interface_descriptor *ds = (void *)_ds;
1813                 pr_vdebug("interface descriptor\n");
1814                 if (length != sizeof *ds)
1815                         goto inv_length;
1816
1817                 __entity(INTERFACE, ds->bInterfaceNumber);
1818                 if (ds->iInterface)
1819                         __entity(STRING, ds->iInterface);
1820         }
1821                 break;
1822
1823         case USB_DT_ENDPOINT: {
1824                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1825                 pr_vdebug("endpoint descriptor\n");
1826                 if (length != USB_DT_ENDPOINT_SIZE &&
1827                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1828                         goto inv_length;
1829                 __entity(ENDPOINT, ds->bEndpointAddress);
1830         }
1831                 break;
1832
1833         case HID_DT_HID:
1834                 pr_vdebug("hid descriptor\n");
1835                 if (length != sizeof(struct hid_descriptor))
1836                         goto inv_length;
1837                 break;
1838
1839         case USB_DT_OTG:
1840                 if (length != sizeof(struct usb_otg_descriptor))
1841                         goto inv_length;
1842                 break;
1843
1844         case USB_DT_INTERFACE_ASSOCIATION: {
1845                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1846                 pr_vdebug("interface association descriptor\n");
1847                 if (length != sizeof *ds)
1848                         goto inv_length;
1849                 if (ds->iFunction)
1850                         __entity(STRING, ds->iFunction);
1851         }
1852                 break;
1853
1854         case USB_DT_SS_ENDPOINT_COMP:
1855                 pr_vdebug("EP SS companion descriptor\n");
1856                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
1857                         goto inv_length;
1858                 break;
1859
1860         case USB_DT_OTHER_SPEED_CONFIG:
1861         case USB_DT_INTERFACE_POWER:
1862         case USB_DT_DEBUG:
1863         case USB_DT_SECURITY:
1864         case USB_DT_CS_RADIO_CONTROL:
1865                 /* TODO */
1866                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1867                 return -EINVAL;
1868
1869         default:
1870                 /* We should never be here */
1871                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1872                 return -EINVAL;
1873
1874 inv_length:
1875                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1876                           _ds->bLength, _ds->bDescriptorType);
1877                 return -EINVAL;
1878         }
1879
1880 #undef __entity
1881 #undef __entity_check_DESCRIPTOR
1882 #undef __entity_check_INTERFACE
1883 #undef __entity_check_STRING
1884 #undef __entity_check_ENDPOINT
1885
1886         return length;
1887 }
1888
1889 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1890                                      ffs_entity_callback entity, void *priv)
1891 {
1892         const unsigned _len = len;
1893         unsigned long num = 0;
1894
1895         ENTER();
1896
1897         for (;;) {
1898                 int ret;
1899
1900                 if (num == count)
1901                         data = NULL;
1902
1903                 /* Record "descriptor" entity */
1904                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1905                 if (unlikely(ret < 0)) {
1906                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1907                                  num, ret);
1908                         return ret;
1909                 }
1910
1911                 if (!data)
1912                         return _len - len;
1913
1914                 ret = ffs_do_single_desc(data, len, entity, priv);
1915                 if (unlikely(ret < 0)) {
1916                         pr_debug("%s returns %d\n", __func__, ret);
1917                         return ret;
1918                 }
1919
1920                 len -= ret;
1921                 data += ret;
1922                 ++num;
1923         }
1924 }
1925
1926 static int __ffs_data_do_entity(enum ffs_entity_type type,
1927                                 u8 *valuep, struct usb_descriptor_header *desc,
1928                                 void *priv)
1929 {
1930         struct ffs_desc_helper *helper = priv;
1931         struct usb_endpoint_descriptor *d;
1932
1933         ENTER();
1934
1935         switch (type) {
1936         case FFS_DESCRIPTOR:
1937                 break;
1938
1939         case FFS_INTERFACE:
1940                 /*
1941                  * Interfaces are indexed from zero so if we
1942                  * encountered interface "n" then there are at least
1943                  * "n+1" interfaces.
1944                  */
1945                 if (*valuep >= helper->interfaces_count)
1946                         helper->interfaces_count = *valuep + 1;
1947                 break;
1948
1949         case FFS_STRING:
1950                 /*
1951                  * Strings are indexed from 1 (0 is magic ;) reserved
1952                  * for languages list or some such)
1953                  */
1954                 if (*valuep > helper->ffs->strings_count)
1955                         helper->ffs->strings_count = *valuep;
1956                 break;
1957
1958         case FFS_ENDPOINT:
1959                 d = (void *)desc;
1960                 helper->eps_count++;
1961                 if (helper->eps_count >= 15)
1962                         return -EINVAL;
1963                 /* Check if descriptors for any speed were already parsed */
1964                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
1965                         helper->ffs->eps_addrmap[helper->eps_count] =
1966                                 d->bEndpointAddress;
1967                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
1968                                 d->bEndpointAddress)
1969                         return -EINVAL;
1970                 break;
1971         }
1972
1973         return 0;
1974 }
1975
1976 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
1977                                    struct usb_os_desc_header *desc)
1978 {
1979         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
1980         u16 w_index = le16_to_cpu(desc->wIndex);
1981
1982         if (bcd_version != 1) {
1983                 pr_vdebug("unsupported os descriptors version: %d",
1984                           bcd_version);
1985                 return -EINVAL;
1986         }
1987         switch (w_index) {
1988         case 0x4:
1989                 *next_type = FFS_OS_DESC_EXT_COMPAT;
1990                 break;
1991         case 0x5:
1992                 *next_type = FFS_OS_DESC_EXT_PROP;
1993                 break;
1994         default:
1995                 pr_vdebug("unsupported os descriptor type: %d", w_index);
1996                 return -EINVAL;
1997         }
1998
1999         return sizeof(*desc);
2000 }
2001
2002 /*
2003  * Process all extended compatibility/extended property descriptors
2004  * of a feature descriptor
2005  */
2006 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2007                                               enum ffs_os_desc_type type,
2008                                               u16 feature_count,
2009                                               ffs_os_desc_callback entity,
2010                                               void *priv,
2011                                               struct usb_os_desc_header *h)
2012 {
2013         int ret;
2014         const unsigned _len = len;
2015
2016         ENTER();
2017
2018         /* loop over all ext compat/ext prop descriptors */
2019         while (feature_count--) {
2020                 ret = entity(type, h, data, len, priv);
2021                 if (unlikely(ret < 0)) {
2022                         pr_debug("bad OS descriptor, type: %d\n", type);
2023                         return ret;
2024                 }
2025                 data += ret;
2026                 len -= ret;
2027         }
2028         return _len - len;
2029 }
2030
2031 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2032 static int __must_check ffs_do_os_descs(unsigned count,
2033                                         char *data, unsigned len,
2034                                         ffs_os_desc_callback entity, void *priv)
2035 {
2036         const unsigned _len = len;
2037         unsigned long num = 0;
2038
2039         ENTER();
2040
2041         for (num = 0; num < count; ++num) {
2042                 int ret;
2043                 enum ffs_os_desc_type type;
2044                 u16 feature_count;
2045                 struct usb_os_desc_header *desc = (void *)data;
2046
2047                 if (len < sizeof(*desc))
2048                         return -EINVAL;
2049
2050                 /*
2051                  * Record "descriptor" entity.
2052                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2053                  * Move the data pointer to the beginning of extended
2054                  * compatibilities proper or extended properties proper
2055                  * portions of the data
2056                  */
2057                 if (le32_to_cpu(desc->dwLength) > len)
2058                         return -EINVAL;
2059
2060                 ret = __ffs_do_os_desc_header(&type, desc);
2061                 if (unlikely(ret < 0)) {
2062                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2063                                  num, ret);
2064                         return ret;
2065                 }
2066                 /*
2067                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2068                  */
2069                 feature_count = le16_to_cpu(desc->wCount);
2070                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2071                     (feature_count > 255 || desc->Reserved))
2072                                 return -EINVAL;
2073                 len -= ret;
2074                 data += ret;
2075
2076                 /*
2077                  * Process all function/property descriptors
2078                  * of this Feature Descriptor
2079                  */
2080                 ret = ffs_do_single_os_desc(data, len, type,
2081                                             feature_count, entity, priv, desc);
2082                 if (unlikely(ret < 0)) {
2083                         pr_debug("%s returns %d\n", __func__, ret);
2084                         return ret;
2085                 }
2086
2087                 len -= ret;
2088                 data += ret;
2089         }
2090         return _len - len;
2091 }
2092
2093 /**
2094  * Validate contents of the buffer from userspace related to OS descriptors.
2095  */
2096 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2097                                  struct usb_os_desc_header *h, void *data,
2098                                  unsigned len, void *priv)
2099 {
2100         struct ffs_data *ffs = priv;
2101         u8 length;
2102
2103         ENTER();
2104
2105         switch (type) {
2106         case FFS_OS_DESC_EXT_COMPAT: {
2107                 struct usb_ext_compat_desc *d = data;
2108                 int i;
2109
2110                 if (len < sizeof(*d) ||
2111                     d->bFirstInterfaceNumber >= ffs->interfaces_count ||
2112                     d->Reserved1)
2113                         return -EINVAL;
2114                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2115                         if (d->Reserved2[i])
2116                                 return -EINVAL;
2117
2118                 length = sizeof(struct usb_ext_compat_desc);
2119         }
2120                 break;
2121         case FFS_OS_DESC_EXT_PROP: {
2122                 struct usb_ext_prop_desc *d = data;
2123                 u32 type, pdl;
2124                 u16 pnl;
2125
2126                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2127                         return -EINVAL;
2128                 length = le32_to_cpu(d->dwSize);
2129                 type = le32_to_cpu(d->dwPropertyDataType);
2130                 if (type < USB_EXT_PROP_UNICODE ||
2131                     type > USB_EXT_PROP_UNICODE_MULTI) {
2132                         pr_vdebug("unsupported os descriptor property type: %d",
2133                                   type);
2134                         return -EINVAL;
2135                 }
2136                 pnl = le16_to_cpu(d->wPropertyNameLength);
2137                 pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
2138                 if (length != 14 + pnl + pdl) {
2139                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2140                                   length, pnl, pdl, type);
2141                         return -EINVAL;
2142                 }
2143                 ++ffs->ms_os_descs_ext_prop_count;
2144                 /* property name reported to the host as "WCHAR"s */
2145                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2146                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2147         }
2148                 break;
2149         default:
2150                 pr_vdebug("unknown descriptor: %d\n", type);
2151                 return -EINVAL;
2152         }
2153         return length;
2154 }
2155
2156 static int __ffs_data_got_descs(struct ffs_data *ffs,
2157                                 char *const _data, size_t len)
2158 {
2159         char *data = _data, *raw_descs;
2160         unsigned os_descs_count = 0, counts[3], flags;
2161         int ret = -EINVAL, i;
2162         struct ffs_desc_helper helper;
2163
2164         ENTER();
2165
2166         if (get_unaligned_le32(data + 4) != len)
2167                 goto error;
2168
2169         switch (get_unaligned_le32(data)) {
2170         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2171                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2172                 data += 8;
2173                 len  -= 8;
2174                 break;
2175         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2176                 flags = get_unaligned_le32(data + 8);
2177                 ffs->user_flags = flags;
2178                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2179                               FUNCTIONFS_HAS_HS_DESC |
2180                               FUNCTIONFS_HAS_SS_DESC |
2181                               FUNCTIONFS_HAS_MS_OS_DESC |
2182                               FUNCTIONFS_VIRTUAL_ADDR |
2183                               FUNCTIONFS_EVENTFD)) {
2184                         ret = -ENOSYS;
2185                         goto error;
2186                 }
2187                 data += 12;
2188                 len  -= 12;
2189                 break;
2190         default:
2191                 goto error;
2192         }
2193
2194         if (flags & FUNCTIONFS_EVENTFD) {
2195                 if (len < 4)
2196                         goto error;
2197                 ffs->ffs_eventfd =
2198                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2199                 if (IS_ERR(ffs->ffs_eventfd)) {
2200                         ret = PTR_ERR(ffs->ffs_eventfd);
2201                         ffs->ffs_eventfd = NULL;
2202                         goto error;
2203                 }
2204                 data += 4;
2205                 len  -= 4;
2206         }
2207
2208         /* Read fs_count, hs_count and ss_count (if present) */
2209         for (i = 0; i < 3; ++i) {
2210                 if (!(flags & (1 << i))) {
2211                         counts[i] = 0;
2212                 } else if (len < 4) {
2213                         goto error;
2214                 } else {
2215                         counts[i] = get_unaligned_le32(data);
2216                         data += 4;
2217                         len  -= 4;
2218                 }
2219         }
2220         if (flags & (1 << i)) {
2221                 os_descs_count = get_unaligned_le32(data);
2222                 data += 4;
2223                 len -= 4;
2224         };
2225
2226         /* Read descriptors */
2227         raw_descs = data;
2228         helper.ffs = ffs;
2229         for (i = 0; i < 3; ++i) {
2230                 if (!counts[i])
2231                         continue;
2232                 helper.interfaces_count = 0;
2233                 helper.eps_count = 0;
2234                 ret = ffs_do_descs(counts[i], data, len,
2235                                    __ffs_data_do_entity, &helper);
2236                 if (ret < 0)
2237                         goto error;
2238                 if (!ffs->eps_count && !ffs->interfaces_count) {
2239                         ffs->eps_count = helper.eps_count;
2240                         ffs->interfaces_count = helper.interfaces_count;
2241                 } else {
2242                         if (ffs->eps_count != helper.eps_count) {
2243                                 ret = -EINVAL;
2244                                 goto error;
2245                         }
2246                         if (ffs->interfaces_count != helper.interfaces_count) {
2247                                 ret = -EINVAL;
2248                                 goto error;
2249                         }
2250                 }
2251                 data += ret;
2252                 len  -= ret;
2253         }
2254         if (os_descs_count) {
2255                 ret = ffs_do_os_descs(os_descs_count, data, len,
2256                                       __ffs_data_do_os_desc, ffs);
2257                 if (ret < 0)
2258                         goto error;
2259                 data += ret;
2260                 len -= ret;
2261         }
2262
2263         if (raw_descs == data || len) {
2264                 ret = -EINVAL;
2265                 goto error;
2266         }
2267
2268         ffs->raw_descs_data     = _data;
2269         ffs->raw_descs          = raw_descs;
2270         ffs->raw_descs_length   = data - raw_descs;
2271         ffs->fs_descs_count     = counts[0];
2272         ffs->hs_descs_count     = counts[1];
2273         ffs->ss_descs_count     = counts[2];
2274         ffs->ms_os_descs_count  = os_descs_count;
2275
2276         return 0;
2277
2278 error:
2279         kfree(_data);
2280         return ret;
2281 }
2282
2283 static int __ffs_data_got_strings(struct ffs_data *ffs,
2284                                   char *const _data, size_t len)
2285 {
2286         u32 str_count, needed_count, lang_count;
2287         struct usb_gadget_strings **stringtabs, *t;
2288         struct usb_string *strings, *s;
2289         const char *data = _data;
2290
2291         ENTER();
2292
2293         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2294                      get_unaligned_le32(data + 4) != len))
2295                 goto error;
2296         str_count  = get_unaligned_le32(data + 8);
2297         lang_count = get_unaligned_le32(data + 12);
2298
2299         /* if one is zero the other must be zero */
2300         if (unlikely(!str_count != !lang_count))
2301                 goto error;
2302
2303         /* Do we have at least as many strings as descriptors need? */
2304         needed_count = ffs->strings_count;
2305         if (unlikely(str_count < needed_count))
2306                 goto error;
2307
2308         /*
2309          * If we don't need any strings just return and free all
2310          * memory.
2311          */
2312         if (!needed_count) {
2313                 kfree(_data);
2314                 return 0;
2315         }
2316
2317         /* Allocate everything in one chunk so there's less maintenance. */
2318         {
2319                 unsigned i = 0;
2320                 vla_group(d);
2321                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2322                         lang_count + 1);
2323                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2324                 vla_item(d, struct usb_string, strings,
2325                         lang_count*(needed_count+1));
2326
2327                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2328
2329                 if (unlikely(!vlabuf)) {
2330                         kfree(_data);
2331                         return -ENOMEM;
2332                 }
2333
2334                 /* Initialize the VLA pointers */
2335                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2336                 t = vla_ptr(vlabuf, d, stringtab);
2337                 i = lang_count;
2338                 do {
2339                         *stringtabs++ = t++;
2340                 } while (--i);
2341                 *stringtabs = NULL;
2342
2343                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2344                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2345                 t = vla_ptr(vlabuf, d, stringtab);
2346                 s = vla_ptr(vlabuf, d, strings);
2347                 strings = s;
2348         }
2349
2350         /* For each language */
2351         data += 16;
2352         len -= 16;
2353
2354         do { /* lang_count > 0 so we can use do-while */
2355                 unsigned needed = needed_count;
2356
2357                 if (unlikely(len < 3))
2358                         goto error_free;
2359                 t->language = get_unaligned_le16(data);
2360                 t->strings  = s;
2361                 ++t;
2362
2363                 data += 2;
2364                 len -= 2;
2365
2366                 /* For each string */
2367                 do { /* str_count > 0 so we can use do-while */
2368                         size_t length = strnlen(data, len);
2369
2370                         if (unlikely(length == len))
2371                                 goto error_free;
2372
2373                         /*
2374                          * User may provide more strings then we need,
2375                          * if that's the case we simply ignore the
2376                          * rest
2377                          */
2378                         if (likely(needed)) {
2379                                 /*
2380                                  * s->id will be set while adding
2381                                  * function to configuration so for
2382                                  * now just leave garbage here.
2383                                  */
2384                                 s->s = data;
2385                                 --needed;
2386                                 ++s;
2387                         }
2388
2389                         data += length + 1;
2390                         len -= length + 1;
2391                 } while (--str_count);
2392
2393                 s->id = 0;   /* terminator */
2394                 s->s = NULL;
2395                 ++s;
2396
2397         } while (--lang_count);
2398
2399         /* Some garbage left? */
2400         if (unlikely(len))
2401                 goto error_free;
2402
2403         /* Done! */
2404         ffs->stringtabs = stringtabs;
2405         ffs->raw_strings = _data;
2406
2407         return 0;
2408
2409 error_free:
2410         kfree(stringtabs);
2411 error:
2412         kfree(_data);
2413         return -EINVAL;
2414 }
2415
2416
2417 /* Events handling and management *******************************************/
2418
2419 static void __ffs_event_add(struct ffs_data *ffs,
2420                             enum usb_functionfs_event_type type)
2421 {
2422         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2423         int neg = 0;
2424
2425         /*
2426          * Abort any unhandled setup
2427          *
2428          * We do not need to worry about some cmpxchg() changing value
2429          * of ffs->setup_state without holding the lock because when
2430          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2431          * the source does nothing.
2432          */
2433         if (ffs->setup_state == FFS_SETUP_PENDING)
2434                 ffs->setup_state = FFS_SETUP_CANCELLED;
2435
2436         /*
2437          * Logic of this function guarantees that there are at most four pending
2438          * evens on ffs->ev.types queue.  This is important because the queue
2439          * has space for four elements only and __ffs_ep0_read_events function
2440          * depends on that limit as well.  If more event types are added, those
2441          * limits have to be revisited or guaranteed to still hold.
2442          */
2443         switch (type) {
2444         case FUNCTIONFS_RESUME:
2445                 rem_type2 = FUNCTIONFS_SUSPEND;
2446                 /* FALL THROUGH */
2447         case FUNCTIONFS_SUSPEND:
2448         case FUNCTIONFS_SETUP:
2449                 rem_type1 = type;
2450                 /* Discard all similar events */
2451                 break;
2452
2453         case FUNCTIONFS_BIND:
2454         case FUNCTIONFS_UNBIND:
2455         case FUNCTIONFS_DISABLE:
2456         case FUNCTIONFS_ENABLE:
2457                 /* Discard everything other then power management. */
2458                 rem_type1 = FUNCTIONFS_SUSPEND;
2459                 rem_type2 = FUNCTIONFS_RESUME;
2460                 neg = 1;
2461                 break;
2462
2463         default:
2464                 WARN(1, "%d: unknown event, this should not happen\n", type);
2465                 return;
2466         }
2467
2468         {
2469                 u8 *ev  = ffs->ev.types, *out = ev;
2470                 unsigned n = ffs->ev.count;
2471                 for (; n; --n, ++ev)
2472                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2473                                 *out++ = *ev;
2474                         else
2475                                 pr_vdebug("purging event %d\n", *ev);
2476                 ffs->ev.count = out - ffs->ev.types;
2477         }
2478
2479         pr_vdebug("adding event %d\n", type);
2480         ffs->ev.types[ffs->ev.count++] = type;
2481         wake_up_locked(&ffs->ev.waitq);
2482         if (ffs->ffs_eventfd)
2483                 eventfd_signal(ffs->ffs_eventfd, 1);
2484 }
2485
2486 static void ffs_event_add(struct ffs_data *ffs,
2487                           enum usb_functionfs_event_type type)
2488 {
2489         unsigned long flags;
2490         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2491         __ffs_event_add(ffs, type);
2492         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2493 }
2494
2495 /* Bind/unbind USB function hooks *******************************************/
2496
2497 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2498 {
2499         int i;
2500
2501         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2502                 if (ffs->eps_addrmap[i] == endpoint_address)
2503                         return i;
2504         return -ENOENT;
2505 }
2506
2507 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2508                                     struct usb_descriptor_header *desc,
2509                                     void *priv)
2510 {
2511         struct usb_endpoint_descriptor *ds = (void *)desc;
2512         struct ffs_function *func = priv;
2513         struct ffs_ep *ffs_ep;
2514         unsigned ep_desc_id;
2515         int idx;
2516         static const char *speed_names[] = { "full", "high", "super" };
2517
2518         if (type != FFS_DESCRIPTOR)
2519                 return 0;
2520
2521         /*
2522          * If ss_descriptors is not NULL, we are reading super speed
2523          * descriptors; if hs_descriptors is not NULL, we are reading high
2524          * speed descriptors; otherwise, we are reading full speed
2525          * descriptors.
2526          */
2527         if (func->function.ss_descriptors) {
2528                 ep_desc_id = 2;
2529                 func->function.ss_descriptors[(long)valuep] = desc;
2530         } else if (func->function.hs_descriptors) {
2531                 ep_desc_id = 1;
2532                 func->function.hs_descriptors[(long)valuep] = desc;
2533         } else {
2534                 ep_desc_id = 0;
2535                 func->function.fs_descriptors[(long)valuep]    = desc;
2536         }
2537
2538         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2539                 return 0;
2540
2541         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2542         if (idx < 0)
2543                 return idx;
2544
2545         ffs_ep = func->eps + idx;
2546
2547         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2548                 pr_err("two %sspeed descriptors for EP %d\n",
2549                           speed_names[ep_desc_id],
2550                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2551                 return -EINVAL;
2552         }
2553         ffs_ep->descs[ep_desc_id] = ds;
2554
2555         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2556         if (ffs_ep->ep) {
2557                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2558                 if (!ds->wMaxPacketSize)
2559                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2560         } else {
2561                 struct usb_request *req;
2562                 struct usb_ep *ep;
2563                 u8 bEndpointAddress;
2564
2565                 /*
2566                  * We back up bEndpointAddress because autoconfig overwrites
2567                  * it with physical endpoint address.
2568                  */
2569                 bEndpointAddress = ds->bEndpointAddress;
2570                 pr_vdebug("autoconfig\n");
2571                 ep = usb_ep_autoconfig(func->gadget, ds);
2572                 if (unlikely(!ep))
2573                         return -ENOTSUPP;
2574                 ep->driver_data = func->eps + idx;
2575
2576                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2577                 if (unlikely(!req))
2578                         return -ENOMEM;
2579
2580                 ffs_ep->ep  = ep;
2581                 ffs_ep->req = req;
2582                 func->eps_revmap[ds->bEndpointAddress &
2583                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2584                 /*
2585                  * If we use virtual address mapping, we restore
2586                  * original bEndpointAddress value.
2587                  */
2588                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2589                         ds->bEndpointAddress = bEndpointAddress;
2590         }
2591         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2592
2593         return 0;
2594 }
2595
2596 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2597                                    struct usb_descriptor_header *desc,
2598                                    void *priv)
2599 {
2600         struct ffs_function *func = priv;
2601         unsigned idx;
2602         u8 newValue;
2603
2604         switch (type) {
2605         default:
2606         case FFS_DESCRIPTOR:
2607                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2608                 return 0;
2609
2610         case FFS_INTERFACE:
2611                 idx = *valuep;
2612                 if (func->interfaces_nums[idx] < 0) {
2613                         int id = usb_interface_id(func->conf, &func->function);
2614                         if (unlikely(id < 0))
2615                                 return id;
2616                         func->interfaces_nums[idx] = id;
2617                 }
2618                 newValue = func->interfaces_nums[idx];
2619                 break;
2620
2621         case FFS_STRING:
2622                 /* String' IDs are allocated when fsf_data is bound to cdev */
2623                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2624                 break;
2625
2626         case FFS_ENDPOINT:
2627                 /*
2628                  * USB_DT_ENDPOINT are handled in
2629                  * __ffs_func_bind_do_descs().
2630                  */
2631                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2632                         return 0;
2633
2634                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2635                 if (unlikely(!func->eps[idx].ep))
2636                         return -EINVAL;
2637
2638                 {
2639                         struct usb_endpoint_descriptor **descs;
2640                         descs = func->eps[idx].descs;
2641                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2642                 }
2643                 break;
2644         }
2645
2646         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2647         *valuep = newValue;
2648         return 0;
2649 }
2650
2651 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2652                                       struct usb_os_desc_header *h, void *data,
2653                                       unsigned len, void *priv)
2654 {
2655         struct ffs_function *func = priv;
2656         u8 length = 0;
2657
2658         switch (type) {
2659         case FFS_OS_DESC_EXT_COMPAT: {
2660                 struct usb_ext_compat_desc *desc = data;
2661                 struct usb_os_desc_table *t;
2662
2663                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2664                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2665                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2666                        ARRAY_SIZE(desc->CompatibleID) +
2667                        ARRAY_SIZE(desc->SubCompatibleID));
2668                 length = sizeof(*desc);
2669         }
2670                 break;
2671         case FFS_OS_DESC_EXT_PROP: {
2672                 struct usb_ext_prop_desc *desc = data;
2673                 struct usb_os_desc_table *t;
2674                 struct usb_os_desc_ext_prop *ext_prop;
2675                 char *ext_prop_name;
2676                 char *ext_prop_data;
2677
2678                 t = &func->function.os_desc_table[h->interface];
2679                 t->if_id = func->interfaces_nums[h->interface];
2680
2681                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2682                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2683
2684                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2685                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2686                 ext_prop->data_len = le32_to_cpu(*(u32 *)
2687                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2688                 length = ext_prop->name_len + ext_prop->data_len + 14;
2689
2690                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2691                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2692                         ext_prop->name_len;
2693
2694                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2695                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2696                         ext_prop->data_len;
2697                 memcpy(ext_prop_data,
2698                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2699                        ext_prop->data_len);
2700                 /* unicode data reported to the host as "WCHAR"s */
2701                 switch (ext_prop->type) {
2702                 case USB_EXT_PROP_UNICODE:
2703                 case USB_EXT_PROP_UNICODE_ENV:
2704                 case USB_EXT_PROP_UNICODE_LINK:
2705                 case USB_EXT_PROP_UNICODE_MULTI:
2706                         ext_prop->data_len *= 2;
2707                         break;
2708                 }
2709                 ext_prop->data = ext_prop_data;
2710
2711                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2712                        ext_prop->name_len);
2713                 /* property name reported to the host as "WCHAR"s */
2714                 ext_prop->name_len *= 2;
2715                 ext_prop->name = ext_prop_name;
2716
2717                 t->os_desc->ext_prop_len +=
2718                         ext_prop->name_len + ext_prop->data_len + 14;
2719                 ++t->os_desc->ext_prop_count;
2720                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2721         }
2722                 break;
2723         default:
2724                 pr_vdebug("unknown descriptor: %d\n", type);
2725         }
2726
2727         return length;
2728 }
2729
2730 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2731                                                 struct usb_configuration *c)
2732 {
2733         struct ffs_function *func = ffs_func_from_usb(f);
2734         struct f_fs_opts *ffs_opts =
2735                 container_of(f->fi, struct f_fs_opts, func_inst);
2736         int ret;
2737
2738         ENTER();
2739
2740         /*
2741          * Legacy gadget triggers binding in functionfs_ready_callback,
2742          * which already uses locking; taking the same lock here would
2743          * cause a deadlock.
2744          *
2745          * Configfs-enabled gadgets however do need ffs_dev_lock.
2746          */
2747         if (!ffs_opts->no_configfs)
2748                 ffs_dev_lock();
2749         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2750         func->ffs = ffs_opts->dev->ffs_data;
2751         if (!ffs_opts->no_configfs)
2752                 ffs_dev_unlock();
2753         if (ret)
2754                 return ERR_PTR(ret);
2755
2756         func->conf = c;
2757         func->gadget = c->cdev->gadget;
2758
2759         /*
2760          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2761          * configurations are bound in sequence with list_for_each_entry,
2762          * in each configuration its functions are bound in sequence
2763          * with list_for_each_entry, so we assume no race condition
2764          * with regard to ffs_opts->bound access
2765          */
2766         if (!ffs_opts->refcnt) {
2767                 ret = functionfs_bind(func->ffs, c->cdev);
2768                 if (ret)
2769                         return ERR_PTR(ret);
2770         }
2771         ffs_opts->refcnt++;
2772         func->function.strings = func->ffs->stringtabs;
2773
2774         return ffs_opts;
2775 }
2776
2777 static int _ffs_func_bind(struct usb_configuration *c,
2778                           struct usb_function *f)
2779 {
2780         struct ffs_function *func = ffs_func_from_usb(f);
2781         struct ffs_data *ffs = func->ffs;
2782
2783         const int full = !!func->ffs->fs_descs_count;
2784         const int high = gadget_is_dualspeed(func->gadget) &&
2785                 func->ffs->hs_descs_count;
2786         const int super = gadget_is_superspeed(func->gadget) &&
2787                 func->ffs->ss_descs_count;
2788
2789         int fs_len, hs_len, ss_len, ret, i;
2790
2791         /* Make it a single chunk, less management later on */
2792         vla_group(d);
2793         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2794         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2795                 full ? ffs->fs_descs_count + 1 : 0);
2796         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2797                 high ? ffs->hs_descs_count + 1 : 0);
2798         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2799                 super ? ffs->ss_descs_count + 1 : 0);
2800         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2801         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2802                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2803         vla_item_with_sz(d, char[16], ext_compat,
2804                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2805         vla_item_with_sz(d, struct usb_os_desc, os_desc,
2806                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2807         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
2808                          ffs->ms_os_descs_ext_prop_count);
2809         vla_item_with_sz(d, char, ext_prop_name,
2810                          ffs->ms_os_descs_ext_prop_name_len);
2811         vla_item_with_sz(d, char, ext_prop_data,
2812                          ffs->ms_os_descs_ext_prop_data_len);
2813         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2814         char *vlabuf;
2815
2816         ENTER();
2817
2818         /* Has descriptors only for speeds gadget does not support */
2819         if (unlikely(!(full | high | super)))
2820                 return -ENOTSUPP;
2821
2822         /* Allocate a single chunk, less management later on */
2823         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
2824         if (unlikely(!vlabuf))
2825                 return -ENOMEM;
2826
2827         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
2828         ffs->ms_os_descs_ext_prop_name_avail =
2829                 vla_ptr(vlabuf, d, ext_prop_name);
2830         ffs->ms_os_descs_ext_prop_data_avail =
2831                 vla_ptr(vlabuf, d, ext_prop_data);
2832
2833         /* Copy descriptors  */
2834         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
2835                ffs->raw_descs_length);
2836
2837         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2838         for (ret = ffs->eps_count; ret; --ret) {
2839                 struct ffs_ep *ptr;
2840
2841                 ptr = vla_ptr(vlabuf, d, eps);
2842                 ptr[ret].num = -1;
2843         }
2844
2845         /* Save pointers
2846          * d_eps == vlabuf, func->eps used to kfree vlabuf later
2847         */
2848         func->eps             = vla_ptr(vlabuf, d, eps);
2849         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
2850
2851         /*
2852          * Go through all the endpoint descriptors and allocate
2853          * endpoints first, so that later we can rewrite the endpoint
2854          * numbers without worrying that it may be described later on.
2855          */
2856         if (likely(full)) {
2857                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
2858                 fs_len = ffs_do_descs(ffs->fs_descs_count,
2859                                       vla_ptr(vlabuf, d, raw_descs),
2860                                       d_raw_descs__sz,
2861                                       __ffs_func_bind_do_descs, func);
2862                 if (unlikely(fs_len < 0)) {
2863                         ret = fs_len;
2864                         goto error;
2865                 }
2866         } else {
2867                 fs_len = 0;
2868         }
2869
2870         if (likely(high)) {
2871                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
2872                 hs_len = ffs_do_descs(ffs->hs_descs_count,
2873                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
2874                                       d_raw_descs__sz - fs_len,
2875                                       __ffs_func_bind_do_descs, func);
2876                 if (unlikely(hs_len < 0)) {
2877                         ret = hs_len;
2878                         goto error;
2879                 }
2880         } else {
2881                 hs_len = 0;
2882         }
2883
2884         if (likely(super)) {
2885                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
2886                 ss_len = ffs_do_descs(ffs->ss_descs_count,
2887                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
2888                                 d_raw_descs__sz - fs_len - hs_len,
2889                                 __ffs_func_bind_do_descs, func);
2890                 if (unlikely(ss_len < 0)) {
2891                         ret = ss_len;
2892                         goto error;
2893                 }
2894         } else {
2895                 ss_len = 0;
2896         }
2897
2898         /*
2899          * Now handle interface numbers allocation and interface and
2900          * endpoint numbers rewriting.  We can do that in one go
2901          * now.
2902          */
2903         ret = ffs_do_descs(ffs->fs_descs_count +
2904                            (high ? ffs->hs_descs_count : 0) +
2905                            (super ? ffs->ss_descs_count : 0),
2906                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
2907                            __ffs_func_bind_do_nums, func);
2908         if (unlikely(ret < 0))
2909                 goto error;
2910
2911         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
2912         if (c->cdev->use_os_string)
2913                 for (i = 0; i < ffs->interfaces_count; ++i) {
2914                         struct usb_os_desc *desc;
2915
2916                         desc = func->function.os_desc_table[i].os_desc =
2917                                 vla_ptr(vlabuf, d, os_desc) +
2918                                 i * sizeof(struct usb_os_desc);
2919                         desc->ext_compat_id =
2920                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
2921                         INIT_LIST_HEAD(&desc->ext_prop);
2922                 }
2923         ret = ffs_do_os_descs(ffs->ms_os_descs_count,
2924                               vla_ptr(vlabuf, d, raw_descs) +
2925                               fs_len + hs_len + ss_len,
2926                               d_raw_descs__sz - fs_len - hs_len - ss_len,
2927                               __ffs_func_bind_do_os_desc, func);
2928         if (unlikely(ret < 0))
2929                 goto error;
2930         func->function.os_desc_n =
2931                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
2932
2933         /* And we're done */
2934         ffs_event_add(ffs, FUNCTIONFS_BIND);
2935         return 0;
2936
2937 error:
2938         /* XXX Do we need to release all claimed endpoints here? */
2939         return ret;
2940 }
2941
2942 static int ffs_func_bind(struct usb_configuration *c,
2943                          struct usb_function *f)
2944 {
2945         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
2946
2947         if (IS_ERR(ffs_opts))
2948                 return PTR_ERR(ffs_opts);
2949
2950         return _ffs_func_bind(c, f);
2951 }
2952
2953
2954 /* Other USB function hooks *************************************************/
2955
2956 static void ffs_reset_work(struct work_struct *work)
2957 {
2958         struct ffs_data *ffs = container_of(work,
2959                 struct ffs_data, reset_work);
2960         ffs_data_reset(ffs);
2961 }
2962
2963 static int ffs_func_set_alt(struct usb_function *f,
2964                             unsigned interface, unsigned alt)
2965 {
2966         struct ffs_function *func = ffs_func_from_usb(f);
2967         struct ffs_data *ffs = func->ffs;
2968         int ret = 0, intf;
2969
2970         if (alt != (unsigned)-1) {
2971                 intf = ffs_func_revmap_intf(func, interface);
2972                 if (unlikely(intf < 0))
2973                         return intf;
2974         }
2975
2976         if (ffs->func)
2977                 ffs_func_eps_disable(ffs->func);
2978
2979         if (ffs->state == FFS_DEACTIVATED) {
2980                 ffs->state = FFS_CLOSING;
2981                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
2982                 schedule_work(&ffs->reset_work);
2983                 return -ENODEV;
2984         }
2985
2986         if (ffs->state != FFS_ACTIVE)
2987                 return -ENODEV;
2988
2989         if (alt == (unsigned)-1) {
2990                 ffs->func = NULL;
2991                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2992                 return 0;
2993         }
2994
2995         ffs->func = func;
2996         ret = ffs_func_eps_enable(func);
2997         if (likely(ret >= 0))
2998                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2999         return ret;
3000 }
3001
3002 static void ffs_func_disable(struct usb_function *f)
3003 {
3004         ffs_func_set_alt(f, 0, (unsigned)-1);
3005 }
3006
3007 static int ffs_func_setup(struct usb_function *f,
3008                           const struct usb_ctrlrequest *creq)
3009 {
3010         struct ffs_function *func = ffs_func_from_usb(f);
3011         struct ffs_data *ffs = func->ffs;
3012         unsigned long flags;
3013         int ret;
3014
3015         ENTER();
3016
3017         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3018         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3019         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3020         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3021         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3022
3023         /*
3024          * Most requests directed to interface go through here
3025          * (notable exceptions are set/get interface) so we need to
3026          * handle them.  All other either handled by composite or
3027          * passed to usb_configuration->setup() (if one is set).  No
3028          * matter, we will handle requests directed to endpoint here
3029          * as well (as it's straightforward) but what to do with any
3030          * other request?
3031          */
3032         if (ffs->state != FFS_ACTIVE)
3033                 return -ENODEV;
3034
3035         switch (creq->bRequestType & USB_RECIP_MASK) {
3036         case USB_RECIP_INTERFACE:
3037                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3038                 if (unlikely(ret < 0))
3039                         return ret;
3040                 break;
3041
3042         case USB_RECIP_ENDPOINT:
3043                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3044                 if (unlikely(ret < 0))
3045                         return ret;
3046                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3047                         ret = func->ffs->eps_addrmap[ret];
3048                 break;
3049
3050         default:
3051                 return -EOPNOTSUPP;
3052         }
3053
3054         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3055         ffs->ev.setup = *creq;
3056         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3057         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3058         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3059
3060         return 0;
3061 }
3062
3063 static void ffs_func_suspend(struct usb_function *f)
3064 {
3065         ENTER();
3066         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3067 }
3068
3069 static void ffs_func_resume(struct usb_function *f)
3070 {
3071         ENTER();
3072         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3073 }
3074
3075
3076 /* Endpoint and interface numbers reverse mapping ***************************/
3077
3078 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3079 {
3080         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3081         return num ? num : -EDOM;
3082 }
3083
3084 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3085 {
3086         short *nums = func->interfaces_nums;
3087         unsigned count = func->ffs->interfaces_count;
3088
3089         for (; count; --count, ++nums) {
3090                 if (*nums >= 0 && *nums == intf)
3091                         return nums - func->interfaces_nums;
3092         }
3093
3094         return -EDOM;
3095 }
3096
3097
3098 /* Devices management *******************************************************/
3099
3100 static LIST_HEAD(ffs_devices);
3101
3102 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3103 {
3104         struct ffs_dev *dev;
3105
3106         list_for_each_entry(dev, &ffs_devices, entry) {
3107                 if (!dev->name || !name)
3108                         continue;
3109                 if (strcmp(dev->name, name) == 0)
3110                         return dev;
3111         }
3112
3113         return NULL;
3114 }
3115
3116 /*
3117  * ffs_lock must be taken by the caller of this function
3118  */
3119 static struct ffs_dev *_ffs_get_single_dev(void)
3120 {
3121         struct ffs_dev *dev;
3122
3123         if (list_is_singular(&ffs_devices)) {
3124                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3125                 if (dev->single)
3126                         return dev;
3127         }
3128
3129         return NULL;
3130 }
3131
3132 /*
3133  * ffs_lock must be taken by the caller of this function
3134  */
3135 static struct ffs_dev *_ffs_find_dev(const char *name)
3136 {
3137         struct ffs_dev *dev;
3138
3139         dev = _ffs_get_single_dev();
3140         if (dev)
3141                 return dev;
3142
3143         return _ffs_do_find_dev(name);
3144 }
3145
3146 /* Configfs support *********************************************************/
3147
3148 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3149 {
3150         return container_of(to_config_group(item), struct f_fs_opts,
3151                             func_inst.group);
3152 }
3153
3154 static void ffs_attr_release(struct config_item *item)
3155 {
3156         struct f_fs_opts *opts = to_ffs_opts(item);
3157
3158         usb_put_function_instance(&opts->func_inst);
3159 }
3160
3161 static struct configfs_item_operations ffs_item_ops = {
3162         .release        = ffs_attr_release,
3163 };
3164
3165 static struct config_item_type ffs_func_type = {
3166         .ct_item_ops    = &ffs_item_ops,
3167         .ct_owner       = THIS_MODULE,
3168 };
3169
3170
3171 /* Function registration interface ******************************************/
3172
3173 static void ffs_free_inst(struct usb_function_instance *f)
3174 {
3175         struct f_fs_opts *opts;
3176
3177         opts = to_f_fs_opts(f);
3178         ffs_dev_lock();
3179         _ffs_free_dev(opts->dev);
3180         ffs_dev_unlock();
3181         kfree(opts);
3182 }
3183
3184 #define MAX_INST_NAME_LEN       40
3185
3186 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3187 {
3188         struct f_fs_opts *opts;
3189         char *ptr;
3190         const char *tmp;
3191         int name_len, ret;
3192
3193         name_len = strlen(name) + 1;
3194         if (name_len > MAX_INST_NAME_LEN)
3195                 return -ENAMETOOLONG;
3196
3197         ptr = kstrndup(name, name_len, GFP_KERNEL);
3198         if (!ptr)
3199                 return -ENOMEM;
3200
3201         opts = to_f_fs_opts(fi);
3202         tmp = NULL;
3203
3204         ffs_dev_lock();
3205
3206         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
3207         ret = _ffs_name_dev(opts->dev, ptr);
3208         if (ret) {
3209                 kfree(ptr);
3210                 ffs_dev_unlock();
3211                 return ret;
3212         }
3213         opts->dev->name_allocated = true;
3214
3215         ffs_dev_unlock();
3216
3217         kfree(tmp);
3218
3219         return 0;
3220 }
3221
3222 static struct usb_function_instance *ffs_alloc_inst(void)
3223 {
3224         struct f_fs_opts *opts;
3225         struct ffs_dev *dev;
3226
3227         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3228         if (!opts)
3229                 return ERR_PTR(-ENOMEM);
3230
3231         opts->func_inst.set_inst_name = ffs_set_inst_name;
3232         opts->func_inst.free_func_inst = ffs_free_inst;
3233         ffs_dev_lock();
3234         dev = _ffs_alloc_dev();
3235         ffs_dev_unlock();
3236         if (IS_ERR(dev)) {
3237                 kfree(opts);
3238                 return ERR_CAST(dev);
3239         }
3240         opts->dev = dev;
3241         dev->opts = opts;
3242
3243         config_group_init_type_name(&opts->func_inst.group, "",
3244                                     &ffs_func_type);
3245         return &opts->func_inst;
3246 }
3247
3248 static void ffs_free(struct usb_function *f)
3249 {
3250         kfree(ffs_func_from_usb(f));
3251 }
3252
3253 static void ffs_func_unbind(struct usb_configuration *c,
3254                             struct usb_function *f)
3255 {
3256         struct ffs_function *func = ffs_func_from_usb(f);
3257         struct ffs_data *ffs = func->ffs;
3258         struct f_fs_opts *opts =
3259                 container_of(f->fi, struct f_fs_opts, func_inst);
3260         struct ffs_ep *ep = func->eps;
3261         unsigned count = ffs->eps_count;
3262         unsigned long flags;
3263
3264         ENTER();
3265         if (ffs->func == func) {
3266                 ffs_func_eps_disable(func);
3267                 ffs->func = NULL;
3268         }
3269
3270         if (!--opts->refcnt)
3271                 functionfs_unbind(ffs);
3272
3273         /* cleanup after autoconfig */
3274         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3275         do {
3276                 if (ep->ep && ep->req)
3277                         usb_ep_free_request(ep->ep, ep->req);
3278                 ep->req = NULL;
3279                 ++ep;
3280         } while (--count);
3281         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3282         kfree(func->eps);
3283         func->eps = NULL;
3284         /*
3285          * eps, descriptors and interfaces_nums are allocated in the
3286          * same chunk so only one free is required.
3287          */
3288         func->function.fs_descriptors = NULL;
3289         func->function.hs_descriptors = NULL;
3290         func->function.ss_descriptors = NULL;
3291         func->interfaces_nums = NULL;
3292
3293         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3294 }
3295
3296 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3297 {
3298         struct ffs_function *func;
3299
3300         ENTER();
3301
3302         func = kzalloc(sizeof(*func), GFP_KERNEL);
3303         if (unlikely(!func))
3304                 return ERR_PTR(-ENOMEM);
3305
3306         func->function.name    = "Function FS Gadget";
3307
3308         func->function.bind    = ffs_func_bind;
3309         func->function.unbind  = ffs_func_unbind;
3310         func->function.set_alt = ffs_func_set_alt;
3311         func->function.disable = ffs_func_disable;
3312         func->function.setup   = ffs_func_setup;
3313         func->function.suspend = ffs_func_suspend;
3314         func->function.resume  = ffs_func_resume;
3315         func->function.free_func = ffs_free;
3316
3317         return &func->function;
3318 }
3319
3320 /*
3321  * ffs_lock must be taken by the caller of this function
3322  */
3323 static struct ffs_dev *_ffs_alloc_dev(void)
3324 {
3325         struct ffs_dev *dev;
3326         int ret;
3327
3328         if (_ffs_get_single_dev())
3329                         return ERR_PTR(-EBUSY);
3330
3331         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3332         if (!dev)
3333                 return ERR_PTR(-ENOMEM);
3334
3335         if (list_empty(&ffs_devices)) {
3336                 ret = functionfs_init();
3337                 if (ret) {
3338                         kfree(dev);
3339                         return ERR_PTR(ret);
3340                 }
3341         }
3342
3343         list_add(&dev->entry, &ffs_devices);
3344
3345         return dev;
3346 }
3347
3348 /*
3349  * ffs_lock must be taken by the caller of this function
3350  * The caller is responsible for "name" being available whenever f_fs needs it
3351  */
3352 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
3353 {
3354         struct ffs_dev *existing;
3355
3356         existing = _ffs_do_find_dev(name);
3357         if (existing)
3358                 return -EBUSY;
3359
3360         dev->name = name;
3361
3362         return 0;
3363 }
3364
3365 /*
3366  * The caller is responsible for "name" being available whenever f_fs needs it
3367  */
3368 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3369 {
3370         int ret;
3371
3372         ffs_dev_lock();
3373         ret = _ffs_name_dev(dev, name);
3374         ffs_dev_unlock();
3375
3376         return ret;
3377 }
3378 EXPORT_SYMBOL_GPL(ffs_name_dev);
3379
3380 int ffs_single_dev(struct ffs_dev *dev)
3381 {
3382         int ret;
3383
3384         ret = 0;
3385         ffs_dev_lock();
3386
3387         if (!list_is_singular(&ffs_devices))
3388                 ret = -EBUSY;
3389         else
3390                 dev->single = true;
3391
3392         ffs_dev_unlock();
3393         return ret;
3394 }
3395 EXPORT_SYMBOL_GPL(ffs_single_dev);
3396
3397 /*
3398  * ffs_lock must be taken by the caller of this function
3399  */
3400 static void _ffs_free_dev(struct ffs_dev *dev)
3401 {
3402         list_del(&dev->entry);
3403         if (dev->name_allocated)
3404                 kfree(dev->name);
3405         kfree(dev);
3406         if (list_empty(&ffs_devices))
3407                 functionfs_cleanup();
3408 }
3409
3410 static void *ffs_acquire_dev(const char *dev_name)
3411 {
3412         struct ffs_dev *ffs_dev;
3413
3414         ENTER();
3415         ffs_dev_lock();
3416
3417         ffs_dev = _ffs_find_dev(dev_name);
3418         if (!ffs_dev)
3419                 ffs_dev = ERR_PTR(-ENOENT);
3420         else if (ffs_dev->mounted)
3421                 ffs_dev = ERR_PTR(-EBUSY);
3422         else if (ffs_dev->ffs_acquire_dev_callback &&
3423             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3424                 ffs_dev = ERR_PTR(-ENOENT);
3425         else
3426                 ffs_dev->mounted = true;
3427
3428         ffs_dev_unlock();
3429         return ffs_dev;
3430 }
3431
3432 static void ffs_release_dev(struct ffs_data *ffs_data)
3433 {
3434         struct ffs_dev *ffs_dev;
3435
3436         ENTER();
3437         ffs_dev_lock();
3438
3439         ffs_dev = ffs_data->private_data;
3440         if (ffs_dev) {
3441                 ffs_dev->mounted = false;
3442
3443                 if (ffs_dev->ffs_release_dev_callback)
3444                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3445         }
3446
3447         ffs_dev_unlock();
3448 }
3449
3450 static int ffs_ready(struct ffs_data *ffs)
3451 {
3452         struct ffs_dev *ffs_obj;
3453         int ret = 0;
3454
3455         ENTER();
3456         ffs_dev_lock();
3457
3458         ffs_obj = ffs->private_data;
3459         if (!ffs_obj) {
3460                 ret = -EINVAL;
3461                 goto done;
3462         }
3463         if (WARN_ON(ffs_obj->desc_ready)) {
3464                 ret = -EBUSY;
3465                 goto done;
3466         }
3467
3468         ffs_obj->desc_ready = true;
3469         ffs_obj->ffs_data = ffs;
3470
3471         if (ffs_obj->ffs_ready_callback)
3472                 ret = ffs_obj->ffs_ready_callback(ffs);
3473
3474 done:
3475         ffs_dev_unlock();
3476         return ret;
3477 }
3478
3479 static void ffs_closed(struct ffs_data *ffs)
3480 {
3481         struct ffs_dev *ffs_obj;
3482
3483         ENTER();
3484         ffs_dev_lock();
3485
3486         ffs_obj = ffs->private_data;
3487         if (!ffs_obj)
3488                 goto done;
3489
3490         ffs_obj->desc_ready = false;
3491
3492         if (ffs_obj->ffs_closed_callback)
3493                 ffs_obj->ffs_closed_callback(ffs);
3494
3495         if (!ffs_obj->opts || ffs_obj->opts->no_configfs
3496             || !ffs_obj->opts->func_inst.group.cg_item.ci_parent)
3497                 goto done;
3498
3499         unregister_gadget_item(ffs_obj->opts->
3500                                func_inst.group.cg_item.ci_parent->ci_parent);
3501 done:
3502         ffs_dev_unlock();
3503 }
3504
3505 /* Misc helper functions ****************************************************/
3506
3507 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3508 {
3509         return nonblock
3510                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3511                 : mutex_lock_interruptible(mutex);
3512 }
3513
3514 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3515 {
3516         char *data;
3517
3518         if (unlikely(!len))
3519                 return NULL;
3520
3521         data = kmalloc(len, GFP_KERNEL);
3522         if (unlikely(!data))
3523                 return ERR_PTR(-ENOMEM);
3524
3525         if (unlikely(__copy_from_user(data, buf, len))) {
3526                 kfree(data);
3527                 return ERR_PTR(-EFAULT);
3528         }
3529
3530         pr_vdebug("Buffer from user space:\n");
3531         ffs_dump_mem("", data, len);
3532
3533         return data;
3534 }
3535
3536 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3537 MODULE_LICENSE("GPL");
3538 MODULE_AUTHOR("Michal Nazarewicz");