drivers/usb/gadget/function/f_fs.c

   1 /*
   2  * f_fs.c -- user mode file system API for USB composite function controllers
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  * Author: Michal Nazarewicz <mina86@mina86.com>
   6  *
   7  * Based on inode.c (GadgetFS) which was:
   8  * Copyright (C) 2003-2004 David Brownell
   9  * Copyright (C) 2003 Agilent Technologies
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  */
  16
  17
  18 /* #define DEBUG */
  19 /* #define VERBOSE_DEBUG */
  20
  21 #include <linux/blkdev.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/export.h>
  24 #include <linux/hid.h>
  25 #include <linux/module.h>
  26 #include <linux/sched/signal.h>
  27 #include <linux/uio.h>
  28 #include <asm/unaligned.h>
  29
  30 #include <linux/usb/composite.h>
  31 #include <linux/usb/functionfs.h>
  32
  33 #include <linux/aio.h>
  34 #include <linux/mmu_context.h>
  35 #include <linux/poll.h>
  36 #include <linux/eventfd.h>
  37
  38 #include "u_fs.h"
  39 #include "u_f.h"
  40 #include "u_os_desc.h"
  41 #include "configfs.h"
  42
  43 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  44
  45 /* Reference counter handling */
  46 static void ffs_data_get(struct ffs_data *ffs);
  47 static void ffs_data_put(struct ffs_data *ffs);
  48 /* Creates new ffs_data object. */
  49 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  50         __attribute__((malloc));
  51
  52 /* Opened counter handling. */
  53 static void ffs_data_opened(struct ffs_data *ffs);
  54 static void ffs_data_closed(struct ffs_data *ffs);
  55
  56 /* Called with ffs->mutex held; take over ownership of data. */
  57 static int __must_check
  58 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  59 static int __must_check
  60 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  61
  62
  63 /* The function structure ***************************************************/
  64
  65 struct ffs_ep;
  66
  67 struct ffs_function {
  68         struct usb_configuration        *conf;
  69         struct usb_gadget               *gadget;
  70         struct ffs_data                 *ffs;
  71
  72         struct ffs_ep                   *eps;
  73         u8                              eps_revmap[16];
  74         short                           *interfaces_nums;
  75
  76         struct usb_function             function;
  77 };
  78
  79
  80 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  81 {
  82         return container_of(f, struct ffs_function, function);
  83 }
  84
  85
  86 static inline enum ffs_setup_state
  87 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  88 {
  89         return (enum ffs_setup_state)
  90                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  91 }
  92
  93
  94 static void ffs_func_eps_disable(struct ffs_function *func);
  95 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  96
  97 static int ffs_func_bind(struct usb_configuration *,
  98                          struct usb_function *);
  99 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 100 static void ffs_func_disable(struct usb_function *);
 101 static int ffs_func_setup(struct usb_function *,
 102                           const struct usb_ctrlrequest *);
 103 static bool ffs_func_req_match(struct usb_function *,
 104                                const struct usb_ctrlrequest *,
 105                                bool config0);
 106 static void ffs_func_suspend(struct usb_function *);
 107 static void ffs_func_resume(struct usb_function *);
 108
 109
 110 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 111 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 112
 113
 114 /* The endpoints structures *************************************************/
 115
 116 struct ffs_ep {
 117         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 118         struct usb_request              *req;   /* P: epfile->mutex */
 119
 120         /* [0]: full speed, [1]: high speed, [2]: super speed */
 121         struct usb_endpoint_descriptor  *descs[3];
 122
 123         u8                              num;
 124
 125         int                             status; /* P: epfile->mutex */
 126 };
 127
 128 struct ffs_epfile {
 129         /* Protects ep->ep and ep->req. */
 130         struct mutex                    mutex;
 131
 132         struct ffs_data                 *ffs;
 133         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 134
 135         struct dentry                   *dentry;
 136
 137         /*
 138          * Buffer for holding data from partial reads which may happen since
 139          * we’re rounding user read requests to a multiple of a max packet size.
 140          *
 141          * The pointer is initialised with NULL value and may be set by
 142          * __ffs_epfile_read_data function to point to a temporary buffer.
 143          *
 144          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 145          * data from said buffer and eventually free it.  Importantly, while the
 146          * function is using the buffer, it sets the pointer to NULL.  This is
 147          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 148          * can never run concurrently (they are synchronised by epfile->mutex)
 149          * so the latter will not assign a new value to the pointer.
 150          *
 151          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 152          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 153          * value is crux of the synchronisation between ffs_func_eps_disable and
 154          * __ffs_epfile_read_data.
 155          *
 156          * Once __ffs_epfile_read_data is about to finish it will try to set the
 157          * pointer back to its old value (as described above), but seeing as the
 158          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 159          * the buffer.
 160          *
 161          * == State transitions ==
 162          *
 163          * • ptr == NULL:  (initial state)
 164          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 165          *   ◦ __ffs_epfile_read_buffered:    nop
 166          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 167          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 168          * • ptr == DROP:
 169          *   ◦ __ffs_epfile_read_buffer_free: nop
 170          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 171          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 172          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 173          * • ptr == buf:
 174          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 175          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 176          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 177          *                                    is always called first
 178          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 179          * • ptr == NULL and reading:
 180          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 181          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 182          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 183          *   ◦ reading finishes and …
 184          *     … all data read:               free buf, go to ptr == NULL
 185          *     … otherwise:                   go to ptr == buf and reading
 186          * • ptr == DROP and reading:
 187          *   ◦ __ffs_epfile_read_buffer_free: nop
 188          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 189          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 190          *   ◦ reading finishes:              free buf, go to ptr == DROP
 191          */
 192         struct ffs_buffer               *read_buffer;
 193 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 194
 195         char                            name[5];
 196
 197         unsigned char                   in;     /* P: ffs->eps_lock */
 198         unsigned char                   isoc;   /* P: ffs->eps_lock */
 199
 200         unsigned char                   _pad;
 201 };
 202
 203 struct ffs_buffer {
 204         size_t length;
 205         char *data;
 206         char storage[];
 207 };
 208
 209 /*  ffs_io_data structure ***************************************************/
 210
 211 struct ffs_io_data {
 212         bool aio;
 213         bool read;
 214
 215         struct kiocb *kiocb;
 216         struct iov_iter data;
 217         const void *to_free;
 218         char *buf;
 219
 220         struct mm_struct *mm;
 221         struct work_struct work;
 222
 223         struct usb_ep *ep;
 224         struct usb_request *req;
 225
 226         struct ffs_data *ffs;
 227 };
 228
 229 struct ffs_desc_helper {
 230         struct ffs_data *ffs;
 231         unsigned interfaces_count;
 232         unsigned eps_count;
 233 };
 234
 235 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 236 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 237
 238 static struct dentry *
 239 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 240                    const struct file_operations *fops);
 241
 242 /* Devices management *******************************************************/
 243
 244 DEFINE_MUTEX(ffs_lock);
 245 EXPORT_SYMBOL_GPL(ffs_lock);
 246
 247 static struct ffs_dev *_ffs_find_dev(const char *name);
 248 static struct ffs_dev *_ffs_alloc_dev(void);
 249 static void _ffs_free_dev(struct ffs_dev *dev);
 250 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data);
 251 static void ffs_release_dev(struct ffs_dev *ffs_dev);
 252 static int ffs_ready(struct ffs_data *ffs);
 253 static void ffs_closed(struct ffs_data *ffs);
 254
 255 /* Misc helper functions ****************************************************/
 256
 257 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 258         __attribute__((warn_unused_result, nonnull));
 259 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 260         __attribute__((warn_unused_result, nonnull));
 261
 262
 263 /* Control file aka ep0 *****************************************************/
 264
 265 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 266 {
 267         struct ffs_data *ffs = req->context;
 268
 269         complete(&ffs->ep0req_completion);
 270 }
 271
 272 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 273 {
 274         struct usb_request *req = ffs->ep0req;
 275         int ret;
 276
 277         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 278
 279         spin_unlock_irq(&ffs->ev.waitq.lock);
 280
 281         req->buf      = data;
 282         req->length   = len;
 283
 284         /*
 285          * UDC layer requires to provide a buffer even for ZLP, but should
 286          * not use it at all. Let's provide some poisoned pointer to catch
 287          * possible bug in the driver.
 288          */
 289         if (req->buf == NULL)
 290                 req->buf = (void *)0xDEADBABE;
 291
 292         reinit_completion(&ffs->ep0req_completion);
 293
 294         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 295         if (unlikely(ret < 0))
 296                 return ret;
 297
 298         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 299         if (unlikely(ret)) {
 300                 usb_ep_dequeue(ffs->gadget->ep0, req);
 301                 return -EINTR;
 302         }
 303
 304         ffs->setup_state = FFS_NO_SETUP;
 305         return req->status ? req->status : req->actual;
 306 }
 307
 308 static int __ffs_ep0_stall(struct ffs_data *ffs)
 309 {
 310         if (ffs->ev.can_stall) {
 311                 pr_vdebug("ep0 stall\n");
 312                 usb_ep_set_halt(ffs->gadget->ep0);
 313                 ffs->setup_state = FFS_NO_SETUP;
 314                 return -EL2HLT;
 315         } else {
 316                 pr_debug("bogus ep0 stall!\n");
 317                 return -ESRCH;
 318         }
 319 }
 320
 321 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 322                              size_t len, loff_t *ptr)
 323 {
 324         struct ffs_data *ffs = file->private_data;
 325         ssize_t ret;
 326         char *data;
 327
 328         ENTER();
 329
 330         /* Fast check if setup was canceled */
 331         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 332                 return -EIDRM;
 333
 334         /* Acquire mutex */
 335         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 336         if (unlikely(ret < 0))
 337                 return ret;
 338
 339         /* Check state */
 340         switch (ffs->state) {
 341         case FFS_READ_DESCRIPTORS:
 342         case FFS_READ_STRINGS:
 343                 /* Copy data */
 344                 if (unlikely(len < 16)) {
 345                         ret = -EINVAL;
 346                         break;
 347                 }
 348
 349                 data = ffs_prepare_buffer(buf, len);
 350                 if (IS_ERR(data)) {
 351                         ret = PTR_ERR(data);
 352                         break;
 353                 }
 354
 355                 /* Handle data */
 356                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 357                         pr_info("read descriptors\n");
 358                         ret = __ffs_data_got_descs(ffs, data, len);
 359                         if (unlikely(ret < 0))
 360                                 break;
 361
 362                         ffs->state = FFS_READ_STRINGS;
 363                         ret = len;
 364                 } else {
 365                         pr_info("read strings\n");
 366                         ret = __ffs_data_got_strings(ffs, data, len);
 367                         if (unlikely(ret < 0))
 368                                 break;
 369
 370                         ret = ffs_epfiles_create(ffs);
 371                         if (unlikely(ret)) {
 372                                 ffs->state = FFS_CLOSING;
 373                                 break;
 374                         }
 375
 376                         ffs->state = FFS_ACTIVE;
 377                         mutex_unlock(&ffs->mutex);
 378
 379                         ret = ffs_ready(ffs);
 380                         if (unlikely(ret < 0)) {
 381                                 ffs->state = FFS_CLOSING;
 382                                 return ret;
 383                         }
 384
 385                         return len;
 386                 }
 387                 break;
 388
 389         case FFS_ACTIVE:
 390                 data = NULL;
 391                 /*
 392                  * We're called from user space, we can use _irq
 393                  * rather then _irqsave
 394                  */
 395                 spin_lock_irq(&ffs->ev.waitq.lock);
 396                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 397                 case FFS_SETUP_CANCELLED:
 398                         ret = -EIDRM;
 399                         goto done_spin;
 400
 401                 case FFS_NO_SETUP:
 402                         ret = -ESRCH;
 403                         goto done_spin;
 404
 405                 case FFS_SETUP_PENDING:
 406                         break;
 407                 }
 408
 409                 /* FFS_SETUP_PENDING */
 410                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 411                         spin_unlock_irq(&ffs->ev.waitq.lock);
 412                         ret = __ffs_ep0_stall(ffs);
 413                         break;
 414                 }
 415
 416                 /* FFS_SETUP_PENDING and not stall */
 417                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 418
 419                 spin_unlock_irq(&ffs->ev.waitq.lock);
 420
 421                 data = ffs_prepare_buffer(buf, len);
 422                 if (IS_ERR(data)) {
 423                         ret = PTR_ERR(data);
 424                         break;
 425                 }
 426
 427                 spin_lock_irq(&ffs->ev.waitq.lock);
 428
 429                 /*
 430                  * We are guaranteed to be still in FFS_ACTIVE state
 431                  * but the state of setup could have changed from
 432                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 433                  * to check for that.  If that happened we copied data
 434                  * from user space in vain but it's unlikely.
 435                  *
 436                  * For sure we are not in FFS_NO_SETUP since this is
 437                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 438                  * transition can be performed and it's protected by
 439                  * mutex.
 440                  */
 441                 if (ffs_setup_state_clear_cancelled(ffs) ==
 442                     FFS_SETUP_CANCELLED) {
 443                         ret = -EIDRM;
 444 done_spin:
 445                         spin_unlock_irq(&ffs->ev.waitq.lock);
 446                 } else {
 447                         /* unlocks spinlock */
 448                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 449                 }
 450                 kfree(data);
 451                 break;
 452
 453         default:
 454                 ret = -EBADFD;
 455                 break;
 456         }
 457
 458         mutex_unlock(&ffs->mutex);
 459         return ret;
 460 }
 461
 462 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 463 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 464                                      size_t n)
 465 {
 466         /*
 467          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 468          * size of ffs->ev.types array (which is four) so that's how much space
 469          * we reserve.
 470          */
 471         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 472         const size_t size = n * sizeof *events;
 473         unsigned i = 0;
 474
 475         memset(events, 0, size);
 476
 477         do {
 478                 events[i].type = ffs->ev.types[i];
 479                 if (events[i].type == FUNCTIONFS_SETUP) {
 480                         events[i].u.setup = ffs->ev.setup;
 481                         ffs->setup_state = FFS_SETUP_PENDING;
 482                 }
 483         } while (++i < n);
 484
 485         ffs->ev.count -= n;
 486         if (ffs->ev.count)
 487                 memmove(ffs->ev.types, ffs->ev.types + n,
 488                         ffs->ev.count * sizeof *ffs->ev.types);
 489
 490         spin_unlock_irq(&ffs->ev.waitq.lock);
 491         mutex_unlock(&ffs->mutex);
 492
 493         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 494 }
 495
 496 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 497                             size_t len, loff_t *ptr)
 498 {
 499         struct ffs_data *ffs = file->private_data;
 500         char *data = NULL;
 501         size_t n;
 502         int ret;
 503
 504         ENTER();
 505
 506         /* Fast check if setup was canceled */
 507         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 508                 return -EIDRM;
 509
 510         /* Acquire mutex */
 511         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 512         if (unlikely(ret < 0))
 513                 return ret;
 514
 515         /* Check state */
 516         if (ffs->state != FFS_ACTIVE) {
 517                 ret = -EBADFD;
 518                 goto done_mutex;
 519         }
 520
 521         /*
 522          * We're called from user space, we can use _irq rather then
 523          * _irqsave
 524          */
 525         spin_lock_irq(&ffs->ev.waitq.lock);
 526
 527         switch (ffs_setup_state_clear_cancelled(ffs)) {
 528         case FFS_SETUP_CANCELLED:
 529                 ret = -EIDRM;
 530                 break;
 531
 532         case FFS_NO_SETUP:
 533                 n = len / sizeof(struct usb_functionfs_event);
 534                 if (unlikely(!n)) {
 535                         ret = -EINVAL;
 536                         break;
 537                 }
 538
 539                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 540                         ret = -EAGAIN;
 541                         break;
 542                 }
 543
 544                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 545                                                         ffs->ev.count)) {
 546                         ret = -EINTR;
 547                         break;
 548                 }
 549
 550                 return __ffs_ep0_read_events(ffs, buf,
 551                                              min(n, (size_t)ffs->ev.count));
 552
 553         case FFS_SETUP_PENDING:
 554                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 555                         spin_unlock_irq(&ffs->ev.waitq.lock);
 556                         ret = __ffs_ep0_stall(ffs);
 557                         goto done_mutex;
 558                 }
 559
 560                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 561
 562                 spin_unlock_irq(&ffs->ev.waitq.lock);
 563
 564                 if (likely(len)) {
 565                         data = kmalloc(len, GFP_KERNEL);
 566                         if (unlikely(!data)) {
 567                                 ret = -ENOMEM;
 568                                 goto done_mutex;
 569                         }
 570                 }
 571
 572                 spin_lock_irq(&ffs->ev.waitq.lock);
 573
 574                 /* See ffs_ep0_write() */
 575                 if (ffs_setup_state_clear_cancelled(ffs) ==
 576                     FFS_SETUP_CANCELLED) {
 577                         ret = -EIDRM;
 578                         break;
 579                 }
 580
 581                 /* unlocks spinlock */
 582                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 583                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 584                         ret = -EFAULT;
 585                 goto done_mutex;
 586
 587         default:
 588                 ret = -EBADFD;
 589                 break;
 590         }
 591
 592         spin_unlock_irq(&ffs->ev.waitq.lock);
 593 done_mutex:
 594         mutex_unlock(&ffs->mutex);
 595         kfree(data);
 596         return ret;
 597 }
 598
 599 static int ffs_ep0_open(struct inode *inode, struct file *file)
 600 {
 601         struct ffs_data *ffs = inode->i_private;
 602
 603         ENTER();
 604
 605         if (unlikely(ffs->state == FFS_CLOSING))
 606                 return -EBUSY;
 607
 608         file->private_data = ffs;
 609         ffs_data_opened(ffs);
 610
 611         return stream_open(inode, file);
 612 }
 613
 614 static int ffs_ep0_release(struct inode *inode, struct file *file)
 615 {
 616         struct ffs_data *ffs = file->private_data;
 617
 618         ENTER();
 619
 620         ffs_data_closed(ffs);
 621
 622         return 0;
 623 }
 624
 625 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 626 {
 627         struct ffs_data *ffs = file->private_data;
 628         struct usb_gadget *gadget = ffs->gadget;
 629         long ret;
 630
 631         ENTER();
 632
 633         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 634                 struct ffs_function *func = ffs->func;
 635                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 636         } else if (gadget && gadget->ops->ioctl) {
 637                 ret = gadget->ops->ioctl(gadget, code, value);
 638         } else {
 639                 ret = -ENOTTY;
 640         }
 641
 642         return ret;
 643 }
 644
 645 static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
 646 {
 647         struct ffs_data *ffs = file->private_data;
 648         unsigned int mask = POLLWRNORM;
 649         int ret;
 650
 651         poll_wait(file, &ffs->ev.waitq, wait);
 652
 653         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 654         if (unlikely(ret < 0))
 655                 return mask;
 656
 657         switch (ffs->state) {
 658         case FFS_READ_DESCRIPTORS:
 659         case FFS_READ_STRINGS:
 660                 mask |= POLLOUT;
 661                 break;
 662
 663         case FFS_ACTIVE:
 664                 switch (ffs->setup_state) {
 665                 case FFS_NO_SETUP:
 666                         if (ffs->ev.count)
 667                                 mask |= POLLIN;
 668                         break;
 669
 670                 case FFS_SETUP_PENDING:
 671                 case FFS_SETUP_CANCELLED:
 672                         mask |= (POLLIN | POLLOUT);
 673                         break;
 674                 }
 675         case FFS_CLOSING:
 676                 break;
 677         case FFS_DEACTIVATED:
 678                 break;
 679         }
 680
 681         mutex_unlock(&ffs->mutex);
 682
 683         return mask;
 684 }
 685
 686 static const struct file_operations ffs_ep0_operations = {
 687         .llseek =       no_llseek,
 688
 689         .open =         ffs_ep0_open,
 690         .write =        ffs_ep0_write,
 691         .read =         ffs_ep0_read,
 692         .release =      ffs_ep0_release,
 693         .unlocked_ioctl =       ffs_ep0_ioctl,
 694         .poll =         ffs_ep0_poll,
 695 };
 696
 697
 698 /* "Normal" endpoints operations ********************************************/
 699
 700 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 701 {
 702         ENTER();
 703         if (likely(req->context)) {
 704                 struct ffs_ep *ep = _ep->driver_data;
 705                 ep->status = req->status ? req->status : req->actual;
 706                 complete(req->context);
 707         }
 708 }
 709
 710 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 711 {
 712         ssize_t ret = copy_to_iter(data, data_len, iter);
 713         if (likely(ret == data_len))
 714                 return ret;
 715
 716         if (unlikely(iov_iter_count(iter)))
 717                 return -EFAULT;
 718
 719         /*
 720          * Dear user space developer!
 721          *
 722          * TL;DR: To stop getting below error message in your kernel log, change
 723          * user space code using functionfs to align read buffers to a max
 724          * packet size.
 725          *
 726          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 727          * packet size.  When unaligned buffer is passed to functionfs, it
 728          * internally uses a larger, aligned buffer so that such UDCs are happy.
 729          *
 730          * Unfortunately, this means that host may send more data than was
 731          * requested in read(2) system call.  f_fs doesn’t know what to do with
 732          * that excess data so it simply drops it.
 733          *
 734          * Was the buffer aligned in the first place, no such problem would
 735          * happen.
 736          *
 737          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 738          * by splitting a request into multiple parts.  This splitting may still
 739          * be a problem though so it’s likely best to align the buffer
 740          * regardless of it being AIO or not..
 741          *
 742          * This only affects OUT endpoints, i.e. reading data with a read(2),
 743          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 744          * affected.
 745          */
 746         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 747                "Align read buffer size to max packet size to avoid the problem.\n",
 748                data_len, ret);
 749
 750         return ret;
 751 }
 752
 753 static void ffs_user_copy_worker(struct work_struct *work)
 754 {
 755         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 756                                                    work);
 757         int ret = io_data->req->status ? io_data->req->status :
 758                                          io_data->req->actual;
 759         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 760
 761         if (io_data->read && ret > 0) {
 762                 mm_segment_t oldfs = get_fs();
 763
 764                 set_fs(USER_DS);
 765                 use_mm(io_data->mm);
 766                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 767                 unuse_mm(io_data->mm);
 768                 set_fs(oldfs);
 769         }
 770
 771         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 772
 773         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 774                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 775
 776         usb_ep_free_request(io_data->ep, io_data->req);
 777
 778         if (io_data->read)
 779                 kfree(io_data->to_free);
 780         kfree(io_data->buf);
 781         kfree(io_data);
 782 }
 783
 784 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 785                                          struct usb_request *req)
 786 {
 787         struct ffs_io_data *io_data = req->context;
 788         struct ffs_data *ffs = io_data->ffs;
 789
 790         ENTER();
 791
 792         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 793         queue_work(ffs->io_completion_wq, &io_data->work);
 794 }
 795
 796 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 797 {
 798         /*
 799          * See comment in struct ffs_epfile for full read_buffer pointer
 800          * synchronisation story.
 801          */
 802         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 803         if (buf && buf != READ_BUFFER_DROP)
 804                 kfree(buf);
 805 }
 806
 807 /* Assumes epfile->mutex is held. */
 808 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 809                                           struct iov_iter *iter)
 810 {
 811         /*
 812          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 813          * the buffer while we are using it.  See comment in struct ffs_epfile
 814          * for full read_buffer pointer synchronisation story.
 815          */
 816         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 817         ssize_t ret;
 818         if (!buf || buf == READ_BUFFER_DROP)
 819                 return 0;
 820
 821         ret = copy_to_iter(buf->data, buf->length, iter);
 822         if (buf->length == ret) {
 823                 kfree(buf);
 824                 return ret;
 825         }
 826
 827         if (unlikely(iov_iter_count(iter))) {
 828                 ret = -EFAULT;
 829         } else {
 830                 buf->length -= ret;
 831                 buf->data += ret;
 832         }
 833
 834         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 835                 kfree(buf);
 836
 837         return ret;
 838 }
 839
 840 /* Assumes epfile->mutex is held. */
 841 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 842                                       void *data, int data_len,
 843                                       struct iov_iter *iter)
 844 {
 845         struct ffs_buffer *buf;
 846
 847         ssize_t ret = copy_to_iter(data, data_len, iter);
 848         if (likely(data_len == ret))
 849                 return ret;
 850
 851         if (unlikely(iov_iter_count(iter)))
 852                 return -EFAULT;
 853
 854         /* See ffs_copy_to_iter for more context. */
 855         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 856                 data_len, ret);
 857
 858         data_len -= ret;
 859         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 860         if (!buf)
 861                 return -ENOMEM;
 862         buf->length = data_len;
 863         buf->data = buf->storage;
 864         memcpy(buf->storage, data + ret, data_len);
 865
 866         /*
 867          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 868          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 869          * in struct ffs_epfile for full read_buffer pointer synchronisation
 870          * story.
 871          */
 872         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 873                 kfree(buf);
 874
 875         return ret;
 876 }
 877
 878 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 879 {
 880         struct ffs_epfile *epfile = file->private_data;
 881         struct usb_request *req;
 882         struct ffs_ep *ep;
 883         char *data = NULL;
 884         ssize_t ret, data_len = -EINVAL;
 885         int halt;
 886
 887         /* Are we still active? */
 888         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 889                 return -ENODEV;
 890
 891         /* Wait for endpoint to be enabled */
 892         ep = epfile->ep;
 893         if (!ep) {
 894                 if (file->f_flags & O_NONBLOCK)
 895                         return -EAGAIN;
 896
 897                 ret = wait_event_interruptible(
 898                                 epfile->ffs->wait, (ep = epfile->ep));
 899                 if (ret)
 900                         return -EINTR;
 901         }
 902
 903         /* Do we halt? */
 904         halt = (!io_data->read == !epfile->in);
 905         if (halt && epfile->isoc)
 906                 return -EINVAL;
 907
 908         /* We will be using request and read_buffer */
 909         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 910         if (unlikely(ret))
 911                 goto error;
 912
 913         /* Allocate & copy */
 914         if (!halt) {
 915                 struct usb_gadget *gadget;
 916
 917                 /*
 918                  * Do we have buffered data from previous partial read?  Check
 919                  * that for synchronous case only because we do not have
 920                  * facility to ‘wake up’ a pending asynchronous read and push
 921                  * buffered data to it which we would need to make things behave
 922                  * consistently.
 923                  */
 924                 if (!io_data->aio && io_data->read) {
 925                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 926                         if (ret)
 927                                 goto error_mutex;
 928                 }
 929
 930                 /*
 931                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 932                  * before the waiting completes, so do not assign to 'gadget'
 933                  * earlier
 934                  */
 935                 gadget = epfile->ffs->gadget;
 936
 937                 spin_lock_irq(&epfile->ffs->eps_lock);
 938                 /* In the meantime, endpoint got disabled or changed. */
 939                 if (epfile->ep != ep) {
 940                         ret = -ESHUTDOWN;
 941                         goto error_lock;
 942                 }
 943                 data_len = iov_iter_count(&io_data->data);
 944                 /*
 945                  * Controller may require buffer size to be aligned to
 946                  * maxpacketsize of an out endpoint.
 947                  */
 948                 if (io_data->read)
 949                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
 950                 spin_unlock_irq(&epfile->ffs->eps_lock);
 951
 952                 data = kmalloc(data_len, GFP_KERNEL);
 953                 if (unlikely(!data)) {
 954                         ret = -ENOMEM;
 955                         goto error_mutex;
 956                 }
 957                 if (!io_data->read &&
 958                     !copy_from_iter_full(data, data_len, &io_data->data)) {
 959                         ret = -EFAULT;
 960                         goto error_mutex;
 961                 }
 962         }
 963
 964         spin_lock_irq(&epfile->ffs->eps_lock);
 965
 966         if (epfile->ep != ep) {
 967                 /* In the meantime, endpoint got disabled or changed. */
 968                 ret = -ESHUTDOWN;
 969         } else if (halt) {
 970                 ret = usb_ep_set_halt(ep->ep);
 971                 if (!ret)
 972                         ret = -EBADMSG;
 973         } else if (unlikely(data_len == -EINVAL)) {
 974                 /*
 975                  * Sanity Check: even though data_len can't be used
 976                  * uninitialized at the time I write this comment, some
 977                  * compilers complain about this situation.
 978                  * In order to keep the code clean from warnings, data_len is
 979                  * being initialized to -EINVAL during its declaration, which
 980                  * means we can't rely on compiler anymore to warn no future
 981                  * changes won't result in data_len being used uninitialized.
 982                  * For such reason, we're adding this redundant sanity check
 983                  * here.
 984                  */
 985                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
 986                 ret = -EINVAL;
 987         } else if (!io_data->aio) {
 988                 DECLARE_COMPLETION_ONSTACK(done);
 989                 bool interrupted = false;
 990
 991                 req = ep->req;
 992                 req->buf      = data;
 993                 req->length   = data_len;
 994
 995                 req->context  = &done;
 996                 req->complete = ffs_epfile_io_complete;
 997
 998                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 999                 if (unlikely(ret < 0))
1000                         goto error_lock;
1001
1002                 spin_unlock_irq(&epfile->ffs->eps_lock);
1003
1004                 if (unlikely(wait_for_completion_interruptible(&done))) {
1005                         /*
1006                          * To avoid race condition with ffs_epfile_io_complete,
1007                          * dequeue the request first then check
1008                          * status. usb_ep_dequeue API should guarantee no race
1009                          * condition with req->complete callback.
1010                          */
1011                         usb_ep_dequeue(ep->ep, req);
1012                         wait_for_completion(&done);
1013                         interrupted = ep->status < 0;
1014                 }
1015
1016                 if (interrupted)
1017                         ret = -EINTR;
1018                 else if (io_data->read && ep->status > 0)
1019                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1020                                                      &io_data->data);
1021                 else
1022                         ret = ep->status;
1023                 goto error_mutex;
1024         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1025                 ret = -ENOMEM;
1026         } else {
1027                 req->buf      = data;
1028                 req->length   = data_len;
1029
1030                 io_data->buf = data;
1031                 io_data->ep = ep->ep;
1032                 io_data->req = req;
1033                 io_data->ffs = epfile->ffs;
1034
1035                 req->context  = io_data;
1036                 req->complete = ffs_epfile_async_io_complete;
1037
1038                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1039                 if (unlikely(ret)) {
1040                         io_data->req = NULL;
1041                         usb_ep_free_request(ep->ep, req);
1042                         goto error_lock;
1043                 }
1044
1045                 ret = -EIOCBQUEUED;
1046                 /*
1047                  * Do not kfree the buffer in this function.  It will be freed
1048                  * by ffs_user_copy_worker.
1049                  */
1050                 data = NULL;
1051         }
1052
1053 error_lock:
1054         spin_unlock_irq(&epfile->ffs->eps_lock);
1055 error_mutex:
1056         mutex_unlock(&epfile->mutex);
1057 error:
1058         kfree(data);
1059         return ret;
1060 }
1061
1062 static int
1063 ffs_epfile_open(struct inode *inode, struct file *file)
1064 {
1065         struct ffs_epfile *epfile = inode->i_private;
1066
1067         ENTER();
1068
1069         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1070                 return -ENODEV;
1071
1072         file->private_data = epfile;
1073         ffs_data_opened(epfile->ffs);
1074
1075         return stream_open(inode, file);
1076 }
1077
1078 static int ffs_aio_cancel(struct kiocb *kiocb)
1079 {
1080         struct ffs_io_data *io_data = kiocb->private;
1081         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1082         unsigned long flags;
1083         int value;
1084
1085         ENTER();
1086
1087         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1088
1089         if (likely(io_data && io_data->ep && io_data->req))
1090                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1091         else
1092                 value = -EINVAL;
1093
1094         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1095
1096         return value;
1097 }
1098
1099 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1100 {
1101         struct ffs_io_data io_data, *p = &io_data;
1102         ssize_t res;
1103
1104         ENTER();
1105
1106         if (!is_sync_kiocb(kiocb)) {
1107                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1108                 if (unlikely(!p))
1109                         return -ENOMEM;
1110                 p->aio = true;
1111         } else {
1112                 memset(p, 0, sizeof(*p));
1113                 p->aio = false;
1114         }
1115
1116         p->read = false;
1117         p->kiocb = kiocb;
1118         p->data = *from;
1119         p->mm = current->mm;
1120
1121         kiocb->private = p;
1122
1123         if (p->aio)
1124                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1125
1126         res = ffs_epfile_io(kiocb->ki_filp, p);
1127         if (res == -EIOCBQUEUED)
1128                 return res;
1129         if (p->aio)
1130                 kfree(p);
1131         else
1132                 *from = p->data;
1133         return res;
1134 }
1135
1136 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1137 {
1138         struct ffs_io_data io_data, *p = &io_data;
1139         ssize_t res;
1140
1141         ENTER();
1142
1143         if (!is_sync_kiocb(kiocb)) {
1144                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1145                 if (unlikely(!p))
1146                         return -ENOMEM;
1147                 p->aio = true;
1148         } else {
1149                 memset(p, 0, sizeof(*p));
1150                 p->aio = false;
1151         }
1152
1153         p->read = true;
1154         p->kiocb = kiocb;
1155         if (p->aio) {
1156                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1157                 if (!p->to_free) {
1158                         kfree(p);
1159                         return -ENOMEM;
1160                 }
1161         } else {
1162                 p->data = *to;
1163                 p->to_free = NULL;
1164         }
1165         p->mm = current->mm;
1166
1167         kiocb->private = p;
1168
1169         if (p->aio)
1170                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1171
1172         res = ffs_epfile_io(kiocb->ki_filp, p);
1173         if (res == -EIOCBQUEUED)
1174                 return res;
1175
1176         if (p->aio) {
1177                 kfree(p->to_free);
1178                 kfree(p);
1179         } else {
1180                 *to = p->data;
1181         }
1182         return res;
1183 }
1184
1185 static int
1186 ffs_epfile_release(struct inode *inode, struct file *file)
1187 {
1188         struct ffs_epfile *epfile = inode->i_private;
1189
1190         ENTER();
1191
1192         __ffs_epfile_read_buffer_free(epfile);
1193         ffs_data_closed(epfile->ffs);
1194
1195         return 0;
1196 }
1197
1198 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1199                              unsigned long value)
1200 {
1201         struct ffs_epfile *epfile = file->private_data;
1202         struct ffs_ep *ep;
1203         int ret;
1204
1205         ENTER();
1206
1207         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1208                 return -ENODEV;
1209
1210         /* Wait for endpoint to be enabled */
1211         ep = epfile->ep;
1212         if (!ep) {
1213                 if (file->f_flags & O_NONBLOCK)
1214                         return -EAGAIN;
1215
1216                 ret = wait_event_interruptible(
1217                                 epfile->ffs->wait, (ep = epfile->ep));
1218                 if (ret)
1219                         return -EINTR;
1220         }
1221
1222         spin_lock_irq(&epfile->ffs->eps_lock);
1223
1224         /* In the meantime, endpoint got disabled or changed. */
1225         if (epfile->ep != ep) {
1226                 spin_unlock_irq(&epfile->ffs->eps_lock);
1227                 return -ESHUTDOWN;
1228         }
1229
1230         switch (code) {
1231         case FUNCTIONFS_FIFO_STATUS:
1232                 ret = usb_ep_fifo_status(epfile->ep->ep);
1233                 break;
1234         case FUNCTIONFS_FIFO_FLUSH:
1235                 usb_ep_fifo_flush(epfile->ep->ep);
1236                 ret = 0;
1237                 break;
1238         case FUNCTIONFS_CLEAR_HALT:
1239                 ret = usb_ep_clear_halt(epfile->ep->ep);
1240                 break;
1241         case FUNCTIONFS_ENDPOINT_REVMAP:
1242                 ret = epfile->ep->num;
1243                 break;
1244         case FUNCTIONFS_ENDPOINT_DESC:
1245         {
1246                 int desc_idx;
1247                 struct usb_endpoint_descriptor desc1, *desc;
1248
1249                 switch (epfile->ffs->gadget->speed) {
1250                 case USB_SPEED_SUPER:
1251                 case USB_SPEED_SUPER_PLUS:
1252                         desc_idx = 2;
1253                         break;
1254                 case USB_SPEED_HIGH:
1255                         desc_idx = 1;
1256                         break;
1257                 default:
1258                         desc_idx = 0;
1259                 }
1260
1261                 desc = epfile->ep->descs[desc_idx];
1262                 memcpy(&desc1, desc, desc->bLength);
1263
1264                 spin_unlock_irq(&epfile->ffs->eps_lock);
1265                 ret = copy_to_user((void *)value, &desc1, desc1.bLength);
1266                 if (ret)
1267                         ret = -EFAULT;
1268                 return ret;
1269         }
1270         default:
1271                 ret = -ENOTTY;
1272         }
1273         spin_unlock_irq(&epfile->ffs->eps_lock);
1274
1275         return ret;
1276 }
1277
1278 static const struct file_operations ffs_epfile_operations = {
1279         .llseek =       no_llseek,
1280
1281         .open =         ffs_epfile_open,
1282         .write_iter =   ffs_epfile_write_iter,
1283         .read_iter =    ffs_epfile_read_iter,
1284         .release =      ffs_epfile_release,
1285         .unlocked_ioctl =       ffs_epfile_ioctl,
1286 };
1287
1288
1289 /* File system and super block operations ***********************************/
1290
1291 /*
1292  * Mounting the file system creates a controller file, used first for
1293  * function configuration then later for event monitoring.
1294  */
1295
1296 static struct inode *__must_check
1297 ffs_sb_make_inode(struct super_block *sb, void *data,
1298                   const struct file_operations *fops,
1299                   const struct inode_operations *iops,
1300                   struct ffs_file_perms *perms)
1301 {
1302         struct inode *inode;
1303
1304         ENTER();
1305
1306         inode = new_inode(sb);
1307
1308         if (likely(inode)) {
1309                 struct timespec ts = current_time(inode);
1310
1311                 inode->i_ino     = get_next_ino();
1312                 inode->i_mode    = perms->mode;
1313                 inode->i_uid     = perms->uid;
1314                 inode->i_gid     = perms->gid;
1315                 inode->i_atime   = ts;
1316                 inode->i_mtime   = ts;
1317                 inode->i_ctime   = ts;
1318                 inode->i_private = data;
1319                 if (fops)
1320                         inode->i_fop = fops;
1321                 if (iops)
1322                         inode->i_op  = iops;
1323         }
1324
1325         return inode;
1326 }
1327
1328 /* Create "regular" file */
1329 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1330                                         const char *name, void *data,
1331                                         const struct file_operations *fops)
1332 {
1333         struct ffs_data *ffs = sb->s_fs_info;
1334         struct dentry   *dentry;
1335         struct inode    *inode;
1336
1337         ENTER();
1338
1339         dentry = d_alloc_name(sb->s_root, name);
1340         if (unlikely(!dentry))
1341                 return NULL;
1342
1343         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1344         if (unlikely(!inode)) {
1345                 dput(dentry);
1346                 return NULL;
1347         }
1348
1349         d_add(dentry, inode);
1350         return dentry;
1351 }
1352
1353 /* Super block */
1354 static const struct super_operations ffs_sb_operations = {
1355         .statfs =       simple_statfs,
1356         .drop_inode =   generic_delete_inode,
1357 };
1358
1359 struct ffs_sb_fill_data {
1360         struct ffs_file_perms perms;
1361         umode_t root_mode;
1362         const char *dev_name;
1363         bool no_disconnect;
1364         struct ffs_data *ffs_data;
1365 };
1366
1367 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1368 {
1369         struct ffs_sb_fill_data *data = _data;
1370         struct inode    *inode;
1371         struct ffs_data *ffs = data->ffs_data;
1372
1373         ENTER();
1374
1375         ffs->sb              = sb;
1376         data->ffs_data       = NULL;
1377         sb->s_fs_info        = ffs;
1378         sb->s_blocksize      = PAGE_SIZE;
1379         sb->s_blocksize_bits = PAGE_SHIFT;
1380         sb->s_magic          = FUNCTIONFS_MAGIC;
1381         sb->s_op             = &ffs_sb_operations;
1382         sb->s_time_gran      = 1;
1383
1384         /* Root inode */
1385         data->perms.mode = data->root_mode;
1386         inode = ffs_sb_make_inode(sb, NULL,
1387                                   &simple_dir_operations,
1388                                   &simple_dir_inode_operations,
1389                                   &data->perms);
1390         sb->s_root = d_make_root(inode);
1391         if (unlikely(!sb->s_root))
1392                 return -ENOMEM;
1393
1394         /* EP0 file */
1395         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1396                                          &ffs_ep0_operations)))
1397                 return -ENOMEM;
1398
1399         return 0;
1400 }
1401
1402 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1403 {
1404         ENTER();
1405
1406         if (!opts || !*opts)
1407                 return 0;
1408
1409         for (;;) {
1410                 unsigned long value;
1411                 char *eq, *comma;
1412
1413                 /* Option limit */
1414                 comma = strchr(opts, ',');
1415                 if (comma)
1416                         *comma = 0;
1417
1418                 /* Value limit */
1419                 eq = strchr(opts, '=');
1420                 if (unlikely(!eq)) {
1421                         pr_err("'=' missing in %s\n", opts);
1422                         return -EINVAL;
1423                 }
1424                 *eq = 0;
1425
1426                 /* Parse value */
1427                 if (kstrtoul(eq + 1, 0, &value)) {
1428                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1429                         return -EINVAL;
1430                 }
1431
1432                 /* Interpret option */
1433                 switch (eq - opts) {
1434                 case 13:
1435                         if (!memcmp(opts, "no_disconnect", 13))
1436                                 data->no_disconnect = !!value;
1437                         else
1438                                 goto invalid;
1439                         break;
1440                 case 5:
1441                         if (!memcmp(opts, "rmode", 5))
1442                                 data->root_mode  = (value & 0555) | S_IFDIR;
1443                         else if (!memcmp(opts, "fmode", 5))
1444                                 data->perms.mode = (value & 0666) | S_IFREG;
1445                         else
1446                                 goto invalid;
1447                         break;
1448
1449                 case 4:
1450                         if (!memcmp(opts, "mode", 4)) {
1451                                 data->root_mode  = (value & 0555) | S_IFDIR;
1452                                 data->perms.mode = (value & 0666) | S_IFREG;
1453                         } else {
1454                                 goto invalid;
1455                         }
1456                         break;
1457
1458                 case 3:
1459                         if (!memcmp(opts, "uid", 3)) {
1460                                 data->perms.uid = make_kuid(current_user_ns(), value);
1461                                 if (!uid_valid(data->perms.uid)) {
1462                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1463                                         return -EINVAL;
1464                                 }
1465                         } else if (!memcmp(opts, "gid", 3)) {
1466                                 data->perms.gid = make_kgid(current_user_ns(), value);
1467                                 if (!gid_valid(data->perms.gid)) {
1468                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1469                                         return -EINVAL;
1470                                 }
1471                         } else {
1472                                 goto invalid;
1473                         }
1474                         break;
1475
1476                 default:
1477 invalid:
1478                         pr_err("%s: invalid option\n", opts);
1479                         return -EINVAL;
1480                 }
1481
1482                 /* Next iteration */
1483                 if (!comma)
1484                         break;
1485                 opts = comma + 1;
1486         }
1487
1488         return 0;
1489 }
1490
1491 /* "mount -t functionfs dev_name /dev/function" ends up here */
1492
1493 static struct dentry *
1494 ffs_fs_mount(struct file_system_type *t, int flags,
1495               const char *dev_name, void *opts)
1496 {
1497         struct ffs_sb_fill_data data = {
1498                 .perms = {
1499                         .mode = S_IFREG | 0600,
1500                         .uid = GLOBAL_ROOT_UID,
1501                         .gid = GLOBAL_ROOT_GID,
1502                 },
1503                 .root_mode = S_IFDIR | 0500,
1504                 .no_disconnect = false,
1505         };
1506         struct dentry *rv;
1507         int ret;
1508         struct ffs_data *ffs;
1509
1510         ENTER();
1511
1512         ret = ffs_fs_parse_opts(&data, opts);
1513         if (unlikely(ret < 0))
1514                 return ERR_PTR(ret);
1515
1516         ffs = ffs_data_new(dev_name);
1517         if (unlikely(!ffs))
1518                 return ERR_PTR(-ENOMEM);
1519         ffs->file_perms = data.perms;
1520         ffs->no_disconnect = data.no_disconnect;
1521
1522         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1523         if (unlikely(!ffs->dev_name)) {
1524                 ffs_data_put(ffs);
1525                 return ERR_PTR(-ENOMEM);
1526         }
1527
1528         ret = ffs_acquire_dev(dev_name, ffs);
1529         if (ret) {
1530                 ffs_data_put(ffs);
1531                 return ERR_PTR(ret);
1532         }
1533         data.ffs_data = ffs;
1534
1535         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1536         if (IS_ERR(rv) && data.ffs_data)
1537                 ffs_data_put(data.ffs_data);
1538         return rv;
1539 }
1540
1541 static void
1542 ffs_fs_kill_sb(struct super_block *sb)
1543 {
1544         ENTER();
1545
1546         kill_litter_super(sb);
1547         if (sb->s_fs_info)
1548                 ffs_data_closed(sb->s_fs_info);
1549 }
1550
1551 static struct file_system_type ffs_fs_type = {
1552         .owner          = THIS_MODULE,
1553         .name           = "functionfs",
1554         .mount          = ffs_fs_mount,
1555         .kill_sb        = ffs_fs_kill_sb,
1556 };
1557 MODULE_ALIAS_FS("functionfs");
1558
1559
1560 /* Driver's main init/cleanup functions *************************************/
1561
1562 static int functionfs_init(void)
1563 {
1564         int ret;
1565
1566         ENTER();
1567
1568         ret = register_filesystem(&ffs_fs_type);
1569         if (likely(!ret))
1570                 pr_info("file system registered\n");
1571         else
1572                 pr_err("failed registering file system (%d)\n", ret);
1573
1574         return ret;
1575 }
1576
1577 static void functionfs_cleanup(void)
1578 {
1579         ENTER();
1580
1581         pr_info("unloading\n");
1582         unregister_filesystem(&ffs_fs_type);
1583 }
1584
1585
1586 /* ffs_data and ffs_function construction and destruction code **************/
1587
1588 static void ffs_data_clear(struct ffs_data *ffs);
1589 static void ffs_data_reset(struct ffs_data *ffs);
1590
1591 static void ffs_data_get(struct ffs_data *ffs)
1592 {
1593         ENTER();
1594
1595         refcount_inc(&ffs->ref);
1596 }
1597
1598 static void ffs_data_opened(struct ffs_data *ffs)
1599 {
1600         ENTER();
1601
1602         refcount_inc(&ffs->ref);
1603         if (atomic_add_return(1, &ffs->opened) == 1 &&
1604                         ffs->state == FFS_DEACTIVATED) {
1605                 ffs->state = FFS_CLOSING;
1606                 ffs_data_reset(ffs);
1607         }
1608 }
1609
1610 static void ffs_data_put(struct ffs_data *ffs)
1611 {
1612         ENTER();
1613
1614         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1615                 pr_info("%s(): freeing\n", __func__);
1616                 ffs_data_clear(ffs);
1617                 ffs_release_dev(ffs->private_data);
1618                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1619                        waitqueue_active(&ffs->ep0req_completion.wait) ||
1620                        waitqueue_active(&ffs->wait));
1621                 destroy_workqueue(ffs->io_completion_wq);
1622                 kfree(ffs->dev_name);
1623                 kfree(ffs);
1624         }
1625 }
1626
1627 static void ffs_data_closed(struct ffs_data *ffs)
1628 {
1629         ENTER();
1630
1631         if (atomic_dec_and_test(&ffs->opened)) {
1632                 if (ffs->no_disconnect) {
1633                         ffs->state = FFS_DEACTIVATED;
1634                         if (ffs->epfiles) {
1635                                 ffs_epfiles_destroy(ffs->epfiles,
1636                                                    ffs->eps_count);
1637                                 ffs->epfiles = NULL;
1638                         }
1639                         if (ffs->setup_state == FFS_SETUP_PENDING)
1640                                 __ffs_ep0_stall(ffs);
1641                 } else {
1642                         ffs->state = FFS_CLOSING;
1643                         ffs_data_reset(ffs);
1644                 }
1645         }
1646         if (atomic_read(&ffs->opened) < 0) {
1647                 ffs->state = FFS_CLOSING;
1648                 ffs_data_reset(ffs);
1649         }
1650
1651         ffs_data_put(ffs);
1652 }
1653
1654 static struct ffs_data *ffs_data_new(const char *dev_name)
1655 {
1656         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1657         if (unlikely(!ffs))
1658                 return NULL;
1659
1660         ENTER();
1661
1662         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1663         if (!ffs->io_completion_wq) {
1664                 kfree(ffs);
1665                 return NULL;
1666         }
1667
1668         refcount_set(&ffs->ref, 1);
1669         atomic_set(&ffs->opened, 0);
1670         ffs->state = FFS_READ_DESCRIPTORS;
1671         mutex_init(&ffs->mutex);
1672         spin_lock_init(&ffs->eps_lock);
1673         init_waitqueue_head(&ffs->ev.waitq);
1674         init_waitqueue_head(&ffs->wait);
1675         init_completion(&ffs->ep0req_completion);
1676
1677         /* XXX REVISIT need to update it in some places, or do we? */
1678         ffs->ev.can_stall = 1;
1679
1680         return ffs;
1681 }
1682
1683 static void ffs_data_clear(struct ffs_data *ffs)
1684 {
1685         ENTER();
1686
1687         ffs_closed(ffs);
1688
1689         BUG_ON(ffs->gadget);
1690
1691         if (ffs->epfiles) {
1692                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1693                 ffs->epfiles = NULL;
1694         }
1695
1696         if (ffs->ffs_eventfd) {
1697                 eventfd_ctx_put(ffs->ffs_eventfd);
1698                 ffs->ffs_eventfd = NULL;
1699         }
1700
1701         kfree(ffs->raw_descs_data);
1702         kfree(ffs->raw_strings);
1703         kfree(ffs->stringtabs);
1704 }
1705
1706 static void ffs_data_reset(struct ffs_data *ffs)
1707 {
1708         ENTER();
1709
1710         ffs_data_clear(ffs);
1711
1712         ffs->raw_descs_data = NULL;
1713         ffs->raw_descs = NULL;
1714         ffs->raw_strings = NULL;
1715         ffs->stringtabs = NULL;
1716
1717         ffs->raw_descs_length = 0;
1718         ffs->fs_descs_count = 0;
1719         ffs->hs_descs_count = 0;
1720         ffs->ss_descs_count = 0;
1721
1722         ffs->strings_count = 0;
1723         ffs->interfaces_count = 0;
1724         ffs->eps_count = 0;
1725
1726         ffs->ev.count = 0;
1727
1728         ffs->state = FFS_READ_DESCRIPTORS;
1729         ffs->setup_state = FFS_NO_SETUP;
1730         ffs->flags = 0;
1731
1732         ffs->ms_os_descs_ext_prop_count = 0;
1733         ffs->ms_os_descs_ext_prop_name_len = 0;
1734         ffs->ms_os_descs_ext_prop_data_len = 0;
1735 }
1736
1737
1738 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1739 {
1740         struct usb_gadget_strings **lang;
1741         int first_id;
1742
1743         ENTER();
1744
1745         if (WARN_ON(ffs->state != FFS_ACTIVE
1746                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1747                 return -EBADFD;
1748
1749         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1750         if (unlikely(first_id < 0))
1751                 return first_id;
1752
1753         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1754         if (unlikely(!ffs->ep0req))
1755                 return -ENOMEM;
1756         ffs->ep0req->complete = ffs_ep0_complete;
1757         ffs->ep0req->context = ffs;
1758
1759         lang = ffs->stringtabs;
1760         if (lang) {
1761                 for (; *lang; ++lang) {
1762                         struct usb_string *str = (*lang)->strings;
1763                         int id = first_id;
1764                         for (; str->s; ++id, ++str)
1765                                 str->id = id;
1766                 }
1767         }
1768
1769         ffs->gadget = cdev->gadget;
1770         ffs_data_get(ffs);
1771         return 0;
1772 }
1773
1774 static void functionfs_unbind(struct ffs_data *ffs)
1775 {
1776         ENTER();
1777
1778         if (!WARN_ON(!ffs->gadget)) {
1779                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1780                 ffs->ep0req = NULL;
1781                 ffs->gadget = NULL;
1782                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1783                 ffs_data_put(ffs);
1784         }
1785 }
1786
1787 static int ffs_epfiles_create(struct ffs_data *ffs)
1788 {
1789         struct ffs_epfile *epfile, *epfiles;
1790         unsigned i, count;
1791
1792         ENTER();
1793
1794         count = ffs->eps_count;
1795         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1796         if (!epfiles)
1797                 return -ENOMEM;
1798
1799         epfile = epfiles;
1800         for (i = 1; i <= count; ++i, ++epfile) {
1801                 epfile->ffs = ffs;
1802                 mutex_init(&epfile->mutex);
1803                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1804                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1805                 else
1806                         sprintf(epfile->name, "ep%u", i);
1807                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1808                                                  epfile,
1809                                                  &ffs_epfile_operations);
1810                 if (unlikely(!epfile->dentry)) {
1811                         ffs_epfiles_destroy(epfiles, i - 1);
1812                         return -ENOMEM;
1813                 }
1814         }
1815
1816         ffs->epfiles = epfiles;
1817         return 0;
1818 }
1819
1820 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1821 {
1822         struct ffs_epfile *epfile = epfiles;
1823
1824         ENTER();
1825
1826         for (; count; --count, ++epfile) {
1827                 BUG_ON(mutex_is_locked(&epfile->mutex));
1828                 if (epfile->dentry) {
1829                         d_delete(epfile->dentry);
1830                         dput(epfile->dentry);
1831                         epfile->dentry = NULL;
1832                 }
1833         }
1834
1835         kfree(epfiles);
1836 }
1837
1838 static void ffs_func_eps_disable(struct ffs_function *func)
1839 {
1840         struct ffs_ep *ep         = func->eps;
1841         struct ffs_epfile *epfile = func->ffs->epfiles;
1842         unsigned count            = func->ffs->eps_count;
1843         unsigned long flags;
1844
1845         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1846         while (count--) {
1847                 /* pending requests get nuked */
1848                 if (likely(ep->ep))
1849                         usb_ep_disable(ep->ep);
1850                 ++ep;
1851
1852                 if (epfile) {
1853                         epfile->ep = NULL;
1854                         __ffs_epfile_read_buffer_free(epfile);
1855                         ++epfile;
1856                 }
1857         }
1858         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1859 }
1860
1861 static int ffs_func_eps_enable(struct ffs_function *func)
1862 {
1863         struct ffs_data *ffs      = func->ffs;
1864         struct ffs_ep *ep         = func->eps;
1865         struct ffs_epfile *epfile = ffs->epfiles;
1866         unsigned count            = ffs->eps_count;
1867         unsigned long flags;
1868         int ret = 0;
1869
1870         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1871         while(count--) {
1872                 ep->ep->driver_data = ep;
1873
1874                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1875                 if (ret) {
1876                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1877                                         __func__, ep->ep->name, ret);
1878                         break;
1879                 }
1880
1881                 ret = usb_ep_enable(ep->ep);
1882                 if (likely(!ret)) {
1883                         epfile->ep = ep;
1884                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1885                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1886                 } else {
1887                         break;
1888                 }
1889
1890                 ++ep;
1891                 ++epfile;
1892         }
1893
1894         wake_up_interruptible(&ffs->wait);
1895         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1896
1897         return ret;
1898 }
1899
1900
1901 /* Parsing and building descriptors and strings *****************************/
1902
1903 /*
1904  * This validates if data pointed by data is a valid USB descriptor as
1905  * well as record how many interfaces, endpoints and strings are
1906  * required by given configuration.  Returns address after the
1907  * descriptor or NULL if data is invalid.
1908  */
1909
1910 enum ffs_entity_type {
1911         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1912 };
1913
1914 enum ffs_os_desc_type {
1915         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1916 };
1917
1918 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1919                                    u8 *valuep,
1920                                    struct usb_descriptor_header *desc,
1921                                    void *priv);
1922
1923 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1924                                     struct usb_os_desc_header *h, void *data,
1925                                     unsigned len, void *priv);
1926
1927 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1928                                            ffs_entity_callback entity,
1929                                            void *priv)
1930 {
1931         struct usb_descriptor_header *_ds = (void *)data;
1932         u8 length;
1933         int ret;
1934
1935         ENTER();
1936
1937         /* At least two bytes are required: length and type */
1938         if (len < 2) {
1939                 pr_vdebug("descriptor too short\n");
1940                 return -EINVAL;
1941         }
1942
1943         /* If we have at least as many bytes as the descriptor takes? */
1944         length = _ds->bLength;
1945         if (len < length) {
1946                 pr_vdebug("descriptor longer then available data\n");
1947                 return -EINVAL;
1948         }
1949
1950 #define __entity_check_INTERFACE(val)  1
1951 #define __entity_check_STRING(val)     (val)
1952 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1953 #define __entity(type, val) do {                                        \
1954                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1955                 if (unlikely(!__entity_check_ ##type(val))) {           \
1956                         pr_vdebug("invalid entity's value\n");          \
1957                         return -EINVAL;                                 \
1958                 }                                                       \
1959                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1960                 if (unlikely(ret < 0)) {                                \
1961                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1962                                  (val), ret);                           \
1963                         return ret;                                     \
1964                 }                                                       \
1965         } while (0)
1966
1967         /* Parse descriptor depending on type. */
1968         switch (_ds->bDescriptorType) {
1969         case USB_DT_DEVICE:
1970         case USB_DT_CONFIG:
1971         case USB_DT_STRING:
1972         case USB_DT_DEVICE_QUALIFIER:
1973                 /* function can't have any of those */
1974                 pr_vdebug("descriptor reserved for gadget: %d\n",
1975                       _ds->bDescriptorType);
1976                 return -EINVAL;
1977
1978         case USB_DT_INTERFACE: {
1979                 struct usb_interface_descriptor *ds = (void *)_ds;
1980                 pr_vdebug("interface descriptor\n");
1981                 if (length != sizeof *ds)
1982                         goto inv_length;
1983
1984                 __entity(INTERFACE, ds->bInterfaceNumber);
1985                 if (ds->iInterface)
1986                         __entity(STRING, ds->iInterface);
1987         }
1988                 break;
1989
1990         case USB_DT_ENDPOINT: {
1991                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1992                 pr_vdebug("endpoint descriptor\n");
1993                 if (length != USB_DT_ENDPOINT_SIZE &&
1994                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1995                         goto inv_length;
1996                 __entity(ENDPOINT, ds->bEndpointAddress);
1997         }
1998                 break;
1999
2000         case HID_DT_HID:
2001                 pr_vdebug("hid descriptor\n");
2002                 if (length != sizeof(struct hid_descriptor))
2003                         goto inv_length;
2004                 break;
2005
2006         case USB_DT_OTG:
2007                 if (length != sizeof(struct usb_otg_descriptor))
2008                         goto inv_length;
2009                 break;
2010
2011         case USB_DT_INTERFACE_ASSOCIATION: {
2012                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2013                 pr_vdebug("interface association descriptor\n");
2014                 if (length != sizeof *ds)
2015                         goto inv_length;
2016                 if (ds->iFunction)
2017                         __entity(STRING, ds->iFunction);
2018         }
2019                 break;
2020
2021         case USB_DT_SS_ENDPOINT_COMP:
2022                 pr_vdebug("EP SS companion descriptor\n");
2023                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2024                         goto inv_length;
2025                 break;
2026
2027         case USB_DT_OTHER_SPEED_CONFIG:
2028         case USB_DT_INTERFACE_POWER:
2029         case USB_DT_DEBUG:
2030         case USB_DT_SECURITY:
2031         case USB_DT_CS_RADIO_CONTROL:
2032                 /* TODO */
2033                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2034                 return -EINVAL;
2035
2036         default:
2037                 /* We should never be here */
2038                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2039                 return -EINVAL;
2040
2041 inv_length:
2042                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2043                           _ds->bLength, _ds->bDescriptorType);
2044                 return -EINVAL;
2045         }
2046
2047 #undef __entity
2048 #undef __entity_check_DESCRIPTOR
2049 #undef __entity_check_INTERFACE
2050 #undef __entity_check_STRING
2051 #undef __entity_check_ENDPOINT
2052
2053         return length;
2054 }
2055
2056 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2057                                      ffs_entity_callback entity, void *priv)
2058 {
2059         const unsigned _len = len;
2060         unsigned long num = 0;
2061
2062         ENTER();
2063
2064         for (;;) {
2065                 int ret;
2066
2067                 if (num == count)
2068                         data = NULL;
2069
2070                 /* Record "descriptor" entity */
2071                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2072                 if (unlikely(ret < 0)) {
2073                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2074                                  num, ret);
2075                         return ret;
2076                 }
2077
2078                 if (!data)
2079                         return _len - len;
2080
2081                 ret = ffs_do_single_desc(data, len, entity, priv);
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                 ++num;
2090         }
2091 }
2092
2093 static int __ffs_data_do_entity(enum ffs_entity_type type,
2094                                 u8 *valuep, struct usb_descriptor_header *desc,
2095                                 void *priv)
2096 {
2097         struct ffs_desc_helper *helper = priv;
2098         struct usb_endpoint_descriptor *d;
2099
2100         ENTER();
2101
2102         switch (type) {
2103         case FFS_DESCRIPTOR:
2104                 break;
2105
2106         case FFS_INTERFACE:
2107                 /*
2108                  * Interfaces are indexed from zero so if we
2109                  * encountered interface "n" then there are at least
2110                  * "n+1" interfaces.
2111                  */
2112                 if (*valuep >= helper->interfaces_count)
2113                         helper->interfaces_count = *valuep + 1;
2114                 break;
2115
2116         case FFS_STRING:
2117                 /*
2118                  * Strings are indexed from 1 (0 is reserved
2119                  * for languages list)
2120                  */
2121                 if (*valuep > helper->ffs->strings_count)
2122                         helper->ffs->strings_count = *valuep;
2123                 break;
2124
2125         case FFS_ENDPOINT:
2126                 d = (void *)desc;
2127                 helper->eps_count++;
2128                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2129                         return -EINVAL;
2130                 /* Check if descriptors for any speed were already parsed */
2131                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2132                         helper->ffs->eps_addrmap[helper->eps_count] =
2133                                 d->bEndpointAddress;
2134                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2135                                 d->bEndpointAddress)
2136                         return -EINVAL;
2137                 break;
2138         }
2139
2140         return 0;
2141 }
2142
2143 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2144                                    struct usb_os_desc_header *desc)
2145 {
2146         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2147         u16 w_index = le16_to_cpu(desc->wIndex);
2148
2149         if (bcd_version != 1) {
2150                 pr_vdebug("unsupported os descriptors version: %d",
2151                           bcd_version);
2152                 return -EINVAL;
2153         }
2154         switch (w_index) {
2155         case 0x4:
2156                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2157                 break;
2158         case 0x5:
2159                 *next_type = FFS_OS_DESC_EXT_PROP;
2160                 break;
2161         default:
2162                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2163                 return -EINVAL;
2164         }
2165
2166         return sizeof(*desc);
2167 }
2168
2169 /*
2170  * Process all extended compatibility/extended property descriptors
2171  * of a feature descriptor
2172  */
2173 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2174                                               enum ffs_os_desc_type type,
2175                                               u16 feature_count,
2176                                               ffs_os_desc_callback entity,
2177                                               void *priv,
2178                                               struct usb_os_desc_header *h)
2179 {
2180         int ret;
2181         const unsigned _len = len;
2182
2183         ENTER();
2184
2185         /* loop over all ext compat/ext prop descriptors */
2186         while (feature_count--) {
2187                 ret = entity(type, h, data, len, priv);
2188                 if (unlikely(ret < 0)) {
2189                         pr_debug("bad OS descriptor, type: %d\n", type);
2190                         return ret;
2191                 }
2192                 data += ret;
2193                 len -= ret;
2194         }
2195         return _len - len;
2196 }
2197
2198 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2199 static int __must_check ffs_do_os_descs(unsigned count,
2200                                         char *data, unsigned len,
2201                                         ffs_os_desc_callback entity, void *priv)
2202 {
2203         const unsigned _len = len;
2204         unsigned long num = 0;
2205
2206         ENTER();
2207
2208         for (num = 0; num < count; ++num) {
2209                 int ret;
2210                 enum ffs_os_desc_type type;
2211                 u16 feature_count;
2212                 struct usb_os_desc_header *desc = (void *)data;
2213
2214                 if (len < sizeof(*desc))
2215                         return -EINVAL;
2216
2217                 /*
2218                  * Record "descriptor" entity.
2219                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2220                  * Move the data pointer to the beginning of extended
2221                  * compatibilities proper or extended properties proper
2222                  * portions of the data
2223                  */
2224                 if (le32_to_cpu(desc->dwLength) > len)
2225                         return -EINVAL;
2226
2227                 ret = __ffs_do_os_desc_header(&type, desc);
2228                 if (unlikely(ret < 0)) {
2229                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2230                                  num, ret);
2231                         return ret;
2232                 }
2233                 /*
2234                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2235                  */
2236                 feature_count = le16_to_cpu(desc->wCount);
2237                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2238                     (feature_count > 255 || desc->Reserved))
2239                                 return -EINVAL;
2240                 len -= ret;
2241                 data += ret;
2242
2243                 /*
2244                  * Process all function/property descriptors
2245                  * of this Feature Descriptor
2246                  */
2247                 ret = ffs_do_single_os_desc(data, len, type,
2248                                             feature_count, entity, priv, desc);
2249                 if (unlikely(ret < 0)) {
2250                         pr_debug("%s returns %d\n", __func__, ret);
2251                         return ret;
2252                 }
2253
2254                 len -= ret;
2255                 data += ret;
2256         }
2257         return _len - len;
2258 }
2259
2260 /**
2261  * Validate contents of the buffer from userspace related to OS descriptors.
2262  */
2263 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2264                                  struct usb_os_desc_header *h, void *data,
2265                                  unsigned len, void *priv)
2266 {
2267         struct ffs_data *ffs = priv;
2268         u8 length;
2269
2270         ENTER();
2271
2272         switch (type) {
2273         case FFS_OS_DESC_EXT_COMPAT: {
2274                 struct usb_ext_compat_desc *d = data;
2275                 int i;
2276
2277                 if (len < sizeof(*d) ||
2278                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2279                         return -EINVAL;
2280                 if (d->Reserved1 != 1) {
2281                         /*
2282                          * According to the spec, Reserved1 must be set to 1
2283                          * but older kernels incorrectly rejected non-zero
2284                          * values.  We fix it here to avoid returning EINVAL
2285                          * in response to values we used to accept.
2286                          */
2287                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2288                         d->Reserved1 = 1;
2289                 }
2290                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2291                         if (d->Reserved2[i])
2292                                 return -EINVAL;
2293
2294                 length = sizeof(struct usb_ext_compat_desc);
2295         }
2296                 break;
2297         case FFS_OS_DESC_EXT_PROP: {
2298                 struct usb_ext_prop_desc *d = data;
2299                 u32 type, pdl;
2300                 u16 pnl;
2301
2302                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2303                         return -EINVAL;
2304                 length = le32_to_cpu(d->dwSize);
2305                 if (len < length)
2306                         return -EINVAL;
2307                 type = le32_to_cpu(d->dwPropertyDataType);
2308                 if (type < USB_EXT_PROP_UNICODE ||
2309                     type > USB_EXT_PROP_UNICODE_MULTI) {
2310                         pr_vdebug("unsupported os descriptor property type: %d",
2311                                   type);
2312                         return -EINVAL;
2313                 }
2314                 pnl = le16_to_cpu(d->wPropertyNameLength);
2315                 if (length < 14 + pnl) {
2316                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2317                                   length, pnl, type);
2318                         return -EINVAL;
2319                 }
2320                 pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
2321                 if (length != 14 + pnl + pdl) {
2322                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2323                                   length, pnl, pdl, type);
2324                         return -EINVAL;
2325                 }
2326                 ++ffs->ms_os_descs_ext_prop_count;
2327                 /* property name reported to the host as "WCHAR"s */
2328                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2329                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2330         }
2331                 break;
2332         default:
2333                 pr_vdebug("unknown descriptor: %d\n", type);
2334                 return -EINVAL;
2335         }
2336         return length;
2337 }
2338
2339 static int __ffs_data_got_descs(struct ffs_data *ffs,
2340                                 char *const _data, size_t len)
2341 {
2342         char *data = _data, *raw_descs;
2343         unsigned os_descs_count = 0, counts[3], flags;
2344         int ret = -EINVAL, i;
2345         struct ffs_desc_helper helper;
2346
2347         ENTER();
2348
2349         if (get_unaligned_le32(data + 4) != len)
2350                 goto error;
2351
2352         switch (get_unaligned_le32(data)) {
2353         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2354                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2355                 data += 8;
2356                 len  -= 8;
2357                 break;
2358         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2359                 flags = get_unaligned_le32(data + 8);
2360                 ffs->user_flags = flags;
2361                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2362                               FUNCTIONFS_HAS_HS_DESC |
2363                               FUNCTIONFS_HAS_SS_DESC |
2364                               FUNCTIONFS_HAS_MS_OS_DESC |
2365                               FUNCTIONFS_VIRTUAL_ADDR |
2366                               FUNCTIONFS_EVENTFD |
2367                               FUNCTIONFS_ALL_CTRL_RECIP |
2368                               FUNCTIONFS_CONFIG0_SETUP)) {
2369                         ret = -ENOSYS;
2370                         goto error;
2371                 }
2372                 data += 12;
2373                 len  -= 12;
2374                 break;
2375         default:
2376                 goto error;
2377         }
2378
2379         if (flags & FUNCTIONFS_EVENTFD) {
2380                 if (len < 4)
2381                         goto error;
2382                 ffs->ffs_eventfd =
2383                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2384                 if (IS_ERR(ffs->ffs_eventfd)) {
2385                         ret = PTR_ERR(ffs->ffs_eventfd);
2386                         ffs->ffs_eventfd = NULL;
2387                         goto error;
2388                 }
2389                 data += 4;
2390                 len  -= 4;
2391         }
2392
2393         /* Read fs_count, hs_count and ss_count (if present) */
2394         for (i = 0; i < 3; ++i) {
2395                 if (!(flags & (1 << i))) {
2396                         counts[i] = 0;
2397                 } else if (len < 4) {
2398                         goto error;
2399                 } else {
2400                         counts[i] = get_unaligned_le32(data);
2401                         data += 4;
2402                         len  -= 4;
2403                 }
2404         }
2405         if (flags & (1 << i)) {
2406                 if (len < 4) {
2407                         goto error;
2408                 }
2409                 os_descs_count = get_unaligned_le32(data);
2410                 data += 4;
2411                 len -= 4;
2412         };
2413
2414         /* Read descriptors */
2415         raw_descs = data;
2416         helper.ffs = ffs;
2417         for (i = 0; i < 3; ++i) {
2418                 if (!counts[i])
2419                         continue;
2420                 helper.interfaces_count = 0;
2421                 helper.eps_count = 0;
2422                 ret = ffs_do_descs(counts[i], data, len,
2423                                    __ffs_data_do_entity, &helper);
2424                 if (ret < 0)
2425                         goto error;
2426                 if (!ffs->eps_count && !ffs->interfaces_count) {
2427                         ffs->eps_count = helper.eps_count;
2428                         ffs->interfaces_count = helper.interfaces_count;
2429                 } else {
2430                         if (ffs->eps_count != helper.eps_count) {
2431                                 ret = -EINVAL;
2432                                 goto error;
2433                         }
2434                         if (ffs->interfaces_count != helper.interfaces_count) {
2435                                 ret = -EINVAL;
2436                                 goto error;
2437                         }
2438                 }
2439                 data += ret;
2440                 len  -= ret;
2441         }
2442         if (os_descs_count) {
2443                 ret = ffs_do_os_descs(os_descs_count, data, len,
2444                                       __ffs_data_do_os_desc, ffs);
2445                 if (ret < 0)
2446                         goto error;
2447                 data += ret;
2448                 len -= ret;
2449         }
2450
2451         if (raw_descs == data || len) {
2452                 ret = -EINVAL;
2453                 goto error;
2454         }
2455
2456         ffs->raw_descs_data     = _data;
2457         ffs->raw_descs          = raw_descs;
2458         ffs->raw_descs_length   = data - raw_descs;
2459         ffs->fs_descs_count     = counts[0];
2460         ffs->hs_descs_count     = counts[1];
2461         ffs->ss_descs_count     = counts[2];
2462         ffs->ms_os_descs_count  = os_descs_count;
2463
2464         return 0;
2465
2466 error:
2467         kfree(_data);
2468         return ret;
2469 }
2470
2471 static int __ffs_data_got_strings(struct ffs_data *ffs,
2472                                   char *const _data, size_t len)
2473 {
2474         u32 str_count, needed_count, lang_count;
2475         struct usb_gadget_strings **stringtabs, *t;
2476         const char *data = _data;
2477         struct usb_string *s;
2478
2479         ENTER();
2480
2481         if (unlikely(len < 16 ||
2482                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2483                      get_unaligned_le32(data + 4) != len))
2484                 goto error;
2485         str_count  = get_unaligned_le32(data + 8);
2486         lang_count = get_unaligned_le32(data + 12);
2487
2488         /* if one is zero the other must be zero */
2489         if (unlikely(!str_count != !lang_count))
2490                 goto error;
2491
2492         /* Do we have at least as many strings as descriptors need? */
2493         needed_count = ffs->strings_count;
2494         if (unlikely(str_count < needed_count))
2495                 goto error;
2496
2497         /*
2498          * If we don't need any strings just return and free all
2499          * memory.
2500          */
2501         if (!needed_count) {
2502                 kfree(_data);
2503                 return 0;
2504         }
2505
2506         /* Allocate everything in one chunk so there's less maintenance. */
2507         {
2508                 unsigned i = 0;
2509                 vla_group(d);
2510                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2511                         lang_count + 1);
2512                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2513                 vla_item(d, struct usb_string, strings,
2514                         lang_count*(needed_count+1));
2515
2516                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2517
2518                 if (unlikely(!vlabuf)) {
2519                         kfree(_data);
2520                         return -ENOMEM;
2521                 }
2522
2523                 /* Initialize the VLA pointers */
2524                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2525                 t = vla_ptr(vlabuf, d, stringtab);
2526                 i = lang_count;
2527                 do {
2528                         *stringtabs++ = t++;
2529                 } while (--i);
2530                 *stringtabs = NULL;
2531
2532                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2533                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2534                 t = vla_ptr(vlabuf, d, stringtab);
2535                 s = vla_ptr(vlabuf, d, strings);
2536         }
2537
2538         /* For each language */
2539         data += 16;
2540         len -= 16;
2541
2542         do { /* lang_count > 0 so we can use do-while */
2543                 unsigned needed = needed_count;
2544                 u32 str_per_lang = str_count;
2545
2546                 if (unlikely(len < 3))
2547                         goto error_free;
2548                 t->language = get_unaligned_le16(data);
2549                 t->strings  = s;
2550                 ++t;
2551
2552                 data += 2;
2553                 len -= 2;
2554
2555                 /* For each string */
2556                 do { /* str_count > 0 so we can use do-while */
2557                         size_t length = strnlen(data, len);
2558
2559                         if (unlikely(length == len))
2560                                 goto error_free;
2561
2562                         /*
2563                          * User may provide more strings then we need,
2564                          * if that's the case we simply ignore the
2565                          * rest
2566                          */
2567                         if (likely(needed)) {
2568                                 /*
2569                                  * s->id will be set while adding
2570                                  * function to configuration so for
2571                                  * now just leave garbage here.
2572                                  */
2573                                 s->s = data;
2574                                 --needed;
2575                                 ++s;
2576                         }
2577
2578                         data += length + 1;
2579                         len -= length + 1;
2580                 } while (--str_per_lang);
2581
2582                 s->id = 0;   /* terminator */
2583                 s->s = NULL;
2584                 ++s;
2585
2586         } while (--lang_count);
2587
2588         /* Some garbage left? */
2589         if (unlikely(len))
2590                 goto error_free;
2591
2592         /* Done! */
2593         ffs->stringtabs = stringtabs;
2594         ffs->raw_strings = _data;
2595
2596         return 0;
2597
2598 error_free:
2599         kfree(stringtabs);
2600 error:
2601         kfree(_data);
2602         return -EINVAL;
2603 }
2604
2605
2606 /* Events handling and management *******************************************/
2607
2608 static void __ffs_event_add(struct ffs_data *ffs,
2609                             enum usb_functionfs_event_type type)
2610 {
2611         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2612         int neg = 0;
2613
2614         /*
2615          * Abort any unhandled setup
2616          *
2617          * We do not need to worry about some cmpxchg() changing value
2618          * of ffs->setup_state without holding the lock because when
2619          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2620          * the source does nothing.
2621          */
2622         if (ffs->setup_state == FFS_SETUP_PENDING)
2623                 ffs->setup_state = FFS_SETUP_CANCELLED;
2624
2625         /*
2626          * Logic of this function guarantees that there are at most four pending
2627          * evens on ffs->ev.types queue.  This is important because the queue
2628          * has space for four elements only and __ffs_ep0_read_events function
2629          * depends on that limit as well.  If more event types are added, those
2630          * limits have to be revisited or guaranteed to still hold.
2631          */
2632         switch (type) {
2633         case FUNCTIONFS_RESUME:
2634                 rem_type2 = FUNCTIONFS_SUSPEND;
2635                 /* FALL THROUGH */
2636         case FUNCTIONFS_SUSPEND:
2637         case FUNCTIONFS_SETUP:
2638                 rem_type1 = type;
2639                 /* Discard all similar events */
2640                 break;
2641
2642         case FUNCTIONFS_BIND:
2643         case FUNCTIONFS_UNBIND:
2644         case FUNCTIONFS_DISABLE:
2645         case FUNCTIONFS_ENABLE:
2646                 /* Discard everything other then power management. */
2647                 rem_type1 = FUNCTIONFS_SUSPEND;
2648                 rem_type2 = FUNCTIONFS_RESUME;
2649                 neg = 1;
2650                 break;
2651
2652         default:
2653                 WARN(1, "%d: unknown event, this should not happen\n", type);
2654                 return;
2655         }
2656
2657         {
2658                 u8 *ev  = ffs->ev.types, *out = ev;
2659                 unsigned n = ffs->ev.count;
2660                 for (; n; --n, ++ev)
2661                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2662                                 *out++ = *ev;
2663                         else
2664                                 pr_vdebug("purging event %d\n", *ev);
2665                 ffs->ev.count = out - ffs->ev.types;
2666         }
2667
2668         pr_vdebug("adding event %d\n", type);
2669         ffs->ev.types[ffs->ev.count++] = type;
2670         wake_up_locked(&ffs->ev.waitq);
2671         if (ffs->ffs_eventfd)
2672                 eventfd_signal(ffs->ffs_eventfd, 1);
2673 }
2674
2675 static void ffs_event_add(struct ffs_data *ffs,
2676                           enum usb_functionfs_event_type type)
2677 {
2678         unsigned long flags;
2679         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2680         __ffs_event_add(ffs, type);
2681         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2682 }
2683
2684 /* Bind/unbind USB function hooks *******************************************/
2685
2686 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2687 {
2688         int i;
2689
2690         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2691                 if (ffs->eps_addrmap[i] == endpoint_address)
2692                         return i;
2693         return -ENOENT;
2694 }
2695
2696 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2697                                     struct usb_descriptor_header *desc,
2698                                     void *priv)
2699 {
2700         struct usb_endpoint_descriptor *ds = (void *)desc;
2701         struct ffs_function *func = priv;
2702         struct ffs_ep *ffs_ep;
2703         unsigned ep_desc_id;
2704         int idx;
2705         static const char *speed_names[] = { "full", "high", "super" };
2706
2707         if (type != FFS_DESCRIPTOR)
2708                 return 0;
2709
2710         /*
2711          * If ss_descriptors is not NULL, we are reading super speed
2712          * descriptors; if hs_descriptors is not NULL, we are reading high
2713          * speed descriptors; otherwise, we are reading full speed
2714          * descriptors.
2715          */
2716         if (func->function.ss_descriptors) {
2717                 ep_desc_id = 2;
2718                 func->function.ss_descriptors[(long)valuep] = desc;
2719         } else if (func->function.hs_descriptors) {
2720                 ep_desc_id = 1;
2721                 func->function.hs_descriptors[(long)valuep] = desc;
2722         } else {
2723                 ep_desc_id = 0;
2724                 func->function.fs_descriptors[(long)valuep]    = desc;
2725         }
2726
2727         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2728                 return 0;
2729
2730         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2731         if (idx < 0)
2732                 return idx;
2733
2734         ffs_ep = func->eps + idx;
2735
2736         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2737                 pr_err("two %sspeed descriptors for EP %d\n",
2738                           speed_names[ep_desc_id],
2739                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2740                 return -EINVAL;
2741         }
2742         ffs_ep->descs[ep_desc_id] = ds;
2743
2744         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2745         if (ffs_ep->ep) {
2746                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2747                 if (!ds->wMaxPacketSize)
2748                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2749         } else {
2750                 struct usb_request *req;
2751                 struct usb_ep *ep;
2752                 u8 bEndpointAddress;
2753
2754                 /*
2755                  * We back up bEndpointAddress because autoconfig overwrites
2756                  * it with physical endpoint address.
2757                  */
2758                 bEndpointAddress = ds->bEndpointAddress;
2759                 pr_vdebug("autoconfig\n");
2760                 ep = usb_ep_autoconfig(func->gadget, ds);
2761                 if (unlikely(!ep))
2762                         return -ENOTSUPP;
2763                 ep->driver_data = func->eps + idx;
2764
2765                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2766                 if (unlikely(!req))
2767                         return -ENOMEM;
2768
2769                 ffs_ep->ep  = ep;
2770                 ffs_ep->req = req;
2771                 func->eps_revmap[ds->bEndpointAddress &
2772                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2773                 /*
2774                  * If we use virtual address mapping, we restore
2775                  * original bEndpointAddress value.
2776                  */
2777                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2778                         ds->bEndpointAddress = bEndpointAddress;
2779         }
2780         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2781
2782         return 0;
2783 }
2784
2785 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2786                                    struct usb_descriptor_header *desc,
2787                                    void *priv)
2788 {
2789         struct ffs_function *func = priv;
2790         unsigned idx;
2791         u8 newValue;
2792
2793         switch (type) {
2794         default:
2795         case FFS_DESCRIPTOR:
2796                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2797                 return 0;
2798
2799         case FFS_INTERFACE:
2800                 idx = *valuep;
2801                 if (func->interfaces_nums[idx] < 0) {
2802                         int id = usb_interface_id(func->conf, &func->function);
2803                         if (unlikely(id < 0))
2804                                 return id;
2805                         func->interfaces_nums[idx] = id;
2806                 }
2807                 newValue = func->interfaces_nums[idx];
2808                 break;
2809
2810         case FFS_STRING:
2811                 /* String' IDs are allocated when fsf_data is bound to cdev */
2812                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2813                 break;
2814
2815         case FFS_ENDPOINT:
2816                 /*
2817                  * USB_DT_ENDPOINT are handled in
2818                  * __ffs_func_bind_do_descs().
2819                  */
2820                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2821                         return 0;
2822
2823                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2824                 if (unlikely(!func->eps[idx].ep))
2825                         return -EINVAL;
2826
2827                 {
2828                         struct usb_endpoint_descriptor **descs;
2829                         descs = func->eps[idx].descs;
2830                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2831                 }
2832                 break;
2833         }
2834
2835         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2836         *valuep = newValue;
2837         return 0;
2838 }
2839
2840 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2841                                       struct usb_os_desc_header *h, void *data,
2842                                       unsigned len, void *priv)
2843 {
2844         struct ffs_function *func = priv;
2845         u8 length = 0;
2846
2847         switch (type) {
2848         case FFS_OS_DESC_EXT_COMPAT: {
2849                 struct usb_ext_compat_desc *desc = data;
2850                 struct usb_os_desc_table *t;
2851
2852                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2853                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2854                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2855                        ARRAY_SIZE(desc->CompatibleID) +
2856                        ARRAY_SIZE(desc->SubCompatibleID));
2857                 length = sizeof(*desc);
2858         }
2859                 break;
2860         case FFS_OS_DESC_EXT_PROP: {
2861                 struct usb_ext_prop_desc *desc = data;
2862                 struct usb_os_desc_table *t;
2863                 struct usb_os_desc_ext_prop *ext_prop;
2864                 char *ext_prop_name;
2865                 char *ext_prop_data;
2866
2867                 t = &func->function.os_desc_table[h->interface];
2868                 t->if_id = func->interfaces_nums[h->interface];
2869
2870                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2871                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2872
2873                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2874                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2875                 ext_prop->data_len = le32_to_cpu(*(u32 *)
2876                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2877                 length = ext_prop->name_len + ext_prop->data_len + 14;
2878
2879                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2880                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2881                         ext_prop->name_len;
2882
2883                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2884                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2885                         ext_prop->data_len;
2886                 memcpy(ext_prop_data,
2887                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2888                        ext_prop->data_len);
2889                 /* unicode data reported to the host as "WCHAR"s */
2890                 switch (ext_prop->type) {
2891                 case USB_EXT_PROP_UNICODE:
2892                 case USB_EXT_PROP_UNICODE_ENV:
2893                 case USB_EXT_PROP_UNICODE_LINK:
2894                 case USB_EXT_PROP_UNICODE_MULTI:
2895                         ext_prop->data_len *= 2;
2896                         break;
2897                 }
2898                 ext_prop->data = ext_prop_data;
2899
2900                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2901                        ext_prop->name_len);
2902                 /* property name reported to the host as "WCHAR"s */
2903                 ext_prop->name_len *= 2;
2904                 ext_prop->name = ext_prop_name;
2905
2906                 t->os_desc->ext_prop_len +=
2907                         ext_prop->name_len + ext_prop->data_len + 14;
2908                 ++t->os_desc->ext_prop_count;
2909                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2910         }
2911                 break;
2912         default:
2913                 pr_vdebug("unknown descriptor: %d\n", type);
2914         }
2915
2916         return length;
2917 }
2918
2919 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2920                                                 struct usb_configuration *c)
2921 {
2922         struct ffs_function *func = ffs_func_from_usb(f);
2923         struct f_fs_opts *ffs_opts =
2924                 container_of(f->fi, struct f_fs_opts, func_inst);
2925         struct ffs_data *ffs_data;
2926         int ret;
2927
2928         ENTER();
2929
2930         /*
2931          * Legacy gadget triggers binding in functionfs_ready_callback,
2932          * which already uses locking; taking the same lock here would
2933          * cause a deadlock.
2934          *
2935          * Configfs-enabled gadgets however do need ffs_dev_lock.
2936          */
2937         if (!ffs_opts->no_configfs)
2938                 ffs_dev_lock();
2939         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2940         ffs_data = ffs_opts->dev->ffs_data;
2941         if (!ffs_opts->no_configfs)
2942                 ffs_dev_unlock();
2943         if (ret)
2944                 return ERR_PTR(ret);
2945
2946         func->ffs = ffs_data;
2947         func->conf = c;
2948         func->gadget = c->cdev->gadget;
2949
2950         /*
2951          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2952          * configurations are bound in sequence with list_for_each_entry,
2953          * in each configuration its functions are bound in sequence
2954          * with list_for_each_entry, so we assume no race condition
2955          * with regard to ffs_opts->bound access
2956          */
2957         if (!ffs_opts->refcnt) {
2958                 ret = functionfs_bind(func->ffs, c->cdev);
2959                 if (ret)
2960                         return ERR_PTR(ret);
2961         }
2962         ffs_opts->refcnt++;
2963         func->function.strings = func->ffs->stringtabs;
2964
2965         return ffs_opts;
2966 }
2967
2968 static int _ffs_func_bind(struct usb_configuration *c,
2969                           struct usb_function *f)
2970 {
2971         struct ffs_function *func = ffs_func_from_usb(f);
2972         struct ffs_data *ffs = func->ffs;
2973
2974         const int full = !!func->ffs->fs_descs_count;
2975         const int high = !!func->ffs->hs_descs_count;
2976         const int super = !!func->ffs->ss_descs_count;
2977
2978         int fs_len, hs_len, ss_len, ret, i;
2979         struct ffs_ep *eps_ptr;
2980
2981         /* Make it a single chunk, less management later on */
2982         vla_group(d);
2983         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2984         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2985                 full ? ffs->fs_descs_count + 1 : 0);
2986         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2987                 high ? ffs->hs_descs_count + 1 : 0);
2988         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2989                 super ? ffs->ss_descs_count + 1 : 0);
2990         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2991         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2992                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2993         vla_item_with_sz(d, char[16], ext_compat,
2994                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2995         vla_item_with_sz(d, struct usb_os_desc, os_desc,
2996                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2997         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
2998                          ffs->ms_os_descs_ext_prop_count);
2999         vla_item_with_sz(d, char, ext_prop_name,
3000                          ffs->ms_os_descs_ext_prop_name_len);
3001         vla_item_with_sz(d, char, ext_prop_data,
3002                          ffs->ms_os_descs_ext_prop_data_len);
3003         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3004         char *vlabuf;
3005
3006         ENTER();
3007
3008         /* Has descriptors only for speeds gadget does not support */
3009         if (unlikely(!(full | high | super)))
3010                 return -ENOTSUPP;
3011
3012         /* Allocate a single chunk, less management later on */
3013         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3014         if (unlikely(!vlabuf))
3015                 return -ENOMEM;
3016
3017         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3018         ffs->ms_os_descs_ext_prop_name_avail =
3019                 vla_ptr(vlabuf, d, ext_prop_name);
3020         ffs->ms_os_descs_ext_prop_data_avail =
3021                 vla_ptr(vlabuf, d, ext_prop_data);
3022
3023         /* Copy descriptors  */
3024         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3025                ffs->raw_descs_length);
3026
3027         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3028         eps_ptr = vla_ptr(vlabuf, d, eps);
3029         for (i = 0; i < ffs->eps_count; i++)
3030                 eps_ptr[i].num = -1;
3031
3032         /* Save pointers
3033          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3034         */
3035         func->eps             = vla_ptr(vlabuf, d, eps);
3036         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3037
3038         /*
3039          * Go through all the endpoint descriptors and allocate
3040          * endpoints first, so that later we can rewrite the endpoint
3041          * numbers without worrying that it may be described later on.
3042          */
3043         if (likely(full)) {
3044                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3045                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3046                                       vla_ptr(vlabuf, d, raw_descs),
3047                                       d_raw_descs__sz,
3048                                       __ffs_func_bind_do_descs, func);
3049                 if (unlikely(fs_len < 0)) {
3050                         ret = fs_len;
3051                         goto error;
3052                 }
3053         } else {
3054                 fs_len = 0;
3055         }
3056
3057         if (likely(high)) {
3058                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3059                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3060                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3061                                       d_raw_descs__sz - fs_len,
3062                                       __ffs_func_bind_do_descs, func);
3063                 if (unlikely(hs_len < 0)) {
3064                         ret = hs_len;
3065                         goto error;
3066                 }
3067         } else {
3068                 hs_len = 0;
3069         }
3070
3071         if (likely(super)) {
3072                 func->function.ss_descriptors = func->function.ssp_descriptors =
3073                         vla_ptr(vlabuf, d, ss_descs);
3074                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3075                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3076                                 d_raw_descs__sz - fs_len - hs_len,
3077                                 __ffs_func_bind_do_descs, func);
3078                 if (unlikely(ss_len < 0)) {
3079                         ret = ss_len;
3080                         goto error;
3081                 }
3082         } else {
3083                 ss_len = 0;
3084         }
3085
3086         /*
3087          * Now handle interface numbers allocation and interface and
3088          * endpoint numbers rewriting.  We can do that in one go
3089          * now.
3090          */
3091         ret = ffs_do_descs(ffs->fs_descs_count +
3092                            (high ? ffs->hs_descs_count : 0) +
3093                            (super ? ffs->ss_descs_count : 0),
3094                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3095                            __ffs_func_bind_do_nums, func);
3096         if (unlikely(ret < 0))
3097                 goto error;
3098
3099         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3100         if (c->cdev->use_os_string) {
3101                 for (i = 0; i < ffs->interfaces_count; ++i) {
3102                         struct usb_os_desc *desc;
3103
3104                         desc = func->function.os_desc_table[i].os_desc =
3105                                 vla_ptr(vlabuf, d, os_desc) +
3106                                 i * sizeof(struct usb_os_desc);
3107                         desc->ext_compat_id =
3108                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3109                         INIT_LIST_HEAD(&desc->ext_prop);
3110                 }
3111                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3112                                       vla_ptr(vlabuf, d, raw_descs) +
3113                                       fs_len + hs_len + ss_len,
3114                                       d_raw_descs__sz - fs_len - hs_len -
3115                                       ss_len,
3116                                       __ffs_func_bind_do_os_desc, func);
3117                 if (unlikely(ret < 0))
3118                         goto error;
3119         }
3120         func->function.os_desc_n =
3121                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3122
3123         /* And we're done */
3124         ffs_event_add(ffs, FUNCTIONFS_BIND);
3125         return 0;
3126
3127 error:
3128         /* XXX Do we need to release all claimed endpoints here? */
3129         return ret;
3130 }
3131
3132 static int ffs_func_bind(struct usb_configuration *c,
3133                          struct usb_function *f)
3134 {
3135         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3136         struct ffs_function *func = ffs_func_from_usb(f);
3137         int ret;
3138
3139         if (IS_ERR(ffs_opts))
3140                 return PTR_ERR(ffs_opts);
3141
3142         ret = _ffs_func_bind(c, f);
3143         if (ret && !--ffs_opts->refcnt)
3144                 functionfs_unbind(func->ffs);
3145
3146         return ret;
3147 }
3148
3149
3150 /* Other USB function hooks *************************************************/
3151
3152 static void ffs_reset_work(struct work_struct *work)
3153 {
3154         struct ffs_data *ffs = container_of(work,
3155                 struct ffs_data, reset_work);
3156         ffs_data_reset(ffs);
3157 }
3158
3159 static int ffs_func_set_alt(struct usb_function *f,
3160                             unsigned interface, unsigned alt)
3161 {
3162         struct ffs_function *func = ffs_func_from_usb(f);
3163         struct ffs_data *ffs = func->ffs;
3164         int ret = 0, intf;
3165
3166         if (alt != (unsigned)-1) {
3167                 intf = ffs_func_revmap_intf(func, interface);
3168                 if (unlikely(intf < 0))
3169                         return intf;
3170         }
3171
3172         if (ffs->func)
3173                 ffs_func_eps_disable(ffs->func);
3174
3175         if (ffs->state == FFS_DEACTIVATED) {
3176                 ffs->state = FFS_CLOSING;
3177                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3178                 schedule_work(&ffs->reset_work);
3179                 return -ENODEV;
3180         }
3181
3182         if (ffs->state != FFS_ACTIVE)
3183                 return -ENODEV;
3184
3185         if (alt == (unsigned)-1) {
3186                 ffs->func = NULL;
3187                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3188                 return 0;
3189         }
3190
3191         ffs->func = func;
3192         ret = ffs_func_eps_enable(func);
3193         if (likely(ret >= 0))
3194                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3195         return ret;
3196 }
3197
3198 static void ffs_func_disable(struct usb_function *f)
3199 {
3200         ffs_func_set_alt(f, 0, (unsigned)-1);
3201 }
3202
3203 static int ffs_func_setup(struct usb_function *f,
3204                           const struct usb_ctrlrequest *creq)
3205 {
3206         struct ffs_function *func = ffs_func_from_usb(f);
3207         struct ffs_data *ffs = func->ffs;
3208         unsigned long flags;
3209         int ret;
3210
3211         ENTER();
3212
3213         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3214         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3215         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3216         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3217         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3218
3219         /*
3220          * Most requests directed to interface go through here
3221          * (notable exceptions are set/get interface) so we need to
3222          * handle them.  All other either handled by composite or
3223          * passed to usb_configuration->setup() (if one is set).  No
3224          * matter, we will handle requests directed to endpoint here
3225          * as well (as it's straightforward).  Other request recipient
3226          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3227          * is being used.
3228          */
3229         if (ffs->state != FFS_ACTIVE)
3230                 return -ENODEV;
3231
3232         switch (creq->bRequestType & USB_RECIP_MASK) {
3233         case USB_RECIP_INTERFACE:
3234                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3235                 if (unlikely(ret < 0))
3236                         return ret;
3237                 break;
3238
3239         case USB_RECIP_ENDPOINT:
3240                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3241                 if (unlikely(ret < 0))
3242                         return ret;
3243                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3244                         ret = func->ffs->eps_addrmap[ret];
3245                 break;
3246
3247         default:
3248                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3249                         ret = le16_to_cpu(creq->wIndex);
3250                 else
3251                         return -EOPNOTSUPP;
3252         }
3253
3254         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3255         ffs->ev.setup = *creq;
3256         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3257         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3258         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3259
3260         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3261 }
3262
3263 static bool ffs_func_req_match(struct usb_function *f,
3264                                const struct usb_ctrlrequest *creq,
3265                                bool config0)
3266 {
3267         struct ffs_function *func = ffs_func_from_usb(f);
3268
3269         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3270                 return false;
3271
3272         switch (creq->bRequestType & USB_RECIP_MASK) {
3273         case USB_RECIP_INTERFACE:
3274                 return (ffs_func_revmap_intf(func,
3275                                              le16_to_cpu(creq->wIndex)) >= 0);
3276         case USB_RECIP_ENDPOINT:
3277                 return (ffs_func_revmap_ep(func,
3278                                            le16_to_cpu(creq->wIndex)) >= 0);
3279         default:
3280                 return (bool) (func->ffs->user_flags &
3281                                FUNCTIONFS_ALL_CTRL_RECIP);
3282         }
3283 }
3284
3285 static void ffs_func_suspend(struct usb_function *f)
3286 {
3287         ENTER();
3288         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3289 }
3290
3291 static void ffs_func_resume(struct usb_function *f)
3292 {
3293         ENTER();
3294         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3295 }
3296
3297
3298 /* Endpoint and interface numbers reverse mapping ***************************/
3299
3300 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3301 {
3302         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3303         return num ? num : -EDOM;
3304 }
3305
3306 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3307 {
3308         short *nums = func->interfaces_nums;
3309         unsigned count = func->ffs->interfaces_count;
3310
3311         for (; count; --count, ++nums) {
3312                 if (*nums >= 0 && *nums == intf)
3313                         return nums - func->interfaces_nums;
3314         }
3315
3316         return -EDOM;
3317 }
3318
3319
3320 /* Devices management *******************************************************/
3321
3322 static LIST_HEAD(ffs_devices);
3323
3324 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3325 {
3326         struct ffs_dev *dev;
3327
3328         if (!name)
3329                 return NULL;
3330
3331         list_for_each_entry(dev, &ffs_devices, entry) {
3332                 if (strcmp(dev->name, name) == 0)
3333                         return dev;
3334         }
3335
3336         return NULL;
3337 }
3338
3339 /*
3340  * ffs_lock must be taken by the caller of this function
3341  */
3342 static struct ffs_dev *_ffs_get_single_dev(void)
3343 {
3344         struct ffs_dev *dev;
3345
3346         if (list_is_singular(&ffs_devices)) {
3347                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3348                 if (dev->single)
3349                         return dev;
3350         }
3351
3352         return NULL;
3353 }
3354
3355 /*
3356  * ffs_lock must be taken by the caller of this function
3357  */
3358 static struct ffs_dev *_ffs_find_dev(const char *name)
3359 {
3360         struct ffs_dev *dev;
3361
3362         dev = _ffs_get_single_dev();
3363         if (dev)
3364                 return dev;
3365
3366         return _ffs_do_find_dev(name);
3367 }
3368
3369 /* Configfs support *********************************************************/
3370
3371 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3372 {
3373         return container_of(to_config_group(item), struct f_fs_opts,
3374                             func_inst.group);
3375 }
3376
3377 static void ffs_attr_release(struct config_item *item)
3378 {
3379         struct f_fs_opts *opts = to_ffs_opts(item);
3380
3381         usb_put_function_instance(&opts->func_inst);
3382 }
3383
3384 static struct configfs_item_operations ffs_item_ops = {
3385         .release        = ffs_attr_release,
3386 };
3387
3388 static struct config_item_type ffs_func_type = {
3389         .ct_item_ops    = &ffs_item_ops,
3390         .ct_owner       = THIS_MODULE,
3391 };
3392
3393
3394 /* Function registration interface ******************************************/
3395
3396 static void ffs_free_inst(struct usb_function_instance *f)
3397 {
3398         struct f_fs_opts *opts;
3399
3400         opts = to_f_fs_opts(f);
3401         ffs_release_dev(opts->dev);
3402         ffs_dev_lock();
3403         _ffs_free_dev(opts->dev);
3404         ffs_dev_unlock();
3405         kfree(opts);
3406 }
3407
3408 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3409 {
3410         if (strlen(name) >= FIELD_SIZEOF(struct ffs_dev, name))
3411                 return -ENAMETOOLONG;
3412         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3413 }
3414
3415 static struct usb_function_instance *ffs_alloc_inst(void)
3416 {
3417         struct f_fs_opts *opts;
3418         struct ffs_dev *dev;
3419
3420         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3421         if (!opts)
3422                 return ERR_PTR(-ENOMEM);
3423
3424         opts->func_inst.set_inst_name = ffs_set_inst_name;
3425         opts->func_inst.free_func_inst = ffs_free_inst;
3426         ffs_dev_lock();
3427         dev = _ffs_alloc_dev();
3428         ffs_dev_unlock();
3429         if (IS_ERR(dev)) {
3430                 kfree(opts);
3431                 return ERR_CAST(dev);
3432         }
3433         opts->dev = dev;
3434         dev->opts = opts;
3435
3436         config_group_init_type_name(&opts->func_inst.group, "",
3437                                     &ffs_func_type);
3438         return &opts->func_inst;
3439 }
3440
3441 static void ffs_free(struct usb_function *f)
3442 {
3443         kfree(ffs_func_from_usb(f));
3444 }
3445
3446 static void ffs_func_unbind(struct usb_configuration *c,
3447                             struct usb_function *f)
3448 {
3449         struct ffs_function *func = ffs_func_from_usb(f);
3450         struct ffs_data *ffs = func->ffs;
3451         struct f_fs_opts *opts =
3452                 container_of(f->fi, struct f_fs_opts, func_inst);
3453         struct ffs_ep *ep = func->eps;
3454         unsigned count = ffs->eps_count;
3455         unsigned long flags;
3456
3457         ENTER();
3458         if (ffs->func == func) {
3459                 ffs_func_eps_disable(func);
3460                 ffs->func = NULL;
3461         }
3462
3463         /* Drain any pending AIO completions */
3464         drain_workqueue(ffs->io_completion_wq);
3465
3466         if (!--opts->refcnt)
3467                 functionfs_unbind(ffs);
3468
3469         /* cleanup after autoconfig */
3470         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3471         while (count--) {
3472                 if (ep->ep && ep->req)
3473                         usb_ep_free_request(ep->ep, ep->req);
3474                 ep->req = NULL;
3475                 ++ep;
3476         }
3477         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3478         kfree(func->eps);
3479         func->eps = NULL;
3480         /*
3481          * eps, descriptors and interfaces_nums are allocated in the
3482          * same chunk so only one free is required.
3483          */
3484         func->function.fs_descriptors = NULL;
3485         func->function.hs_descriptors = NULL;
3486         func->function.ss_descriptors = NULL;
3487         func->function.ssp_descriptors = NULL;
3488         func->interfaces_nums = NULL;
3489
3490         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3491 }
3492
3493 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3494 {
3495         struct ffs_function *func;
3496
3497         ENTER();
3498
3499         func = kzalloc(sizeof(*func), GFP_KERNEL);
3500         if (unlikely(!func))
3501                 return ERR_PTR(-ENOMEM);
3502
3503         func->function.name    = "Function FS Gadget";
3504
3505         func->function.bind    = ffs_func_bind;
3506         func->function.unbind  = ffs_func_unbind;
3507         func->function.set_alt = ffs_func_set_alt;
3508         func->function.disable = ffs_func_disable;
3509         func->function.setup   = ffs_func_setup;
3510         func->function.req_match = ffs_func_req_match;
3511         func->function.suspend = ffs_func_suspend;
3512         func->function.resume  = ffs_func_resume;
3513         func->function.free_func = ffs_free;
3514
3515         return &func->function;
3516 }
3517
3518 /*
3519  * ffs_lock must be taken by the caller of this function
3520  */
3521 static struct ffs_dev *_ffs_alloc_dev(void)
3522 {
3523         struct ffs_dev *dev;
3524         int ret;
3525
3526         if (_ffs_get_single_dev())
3527                         return ERR_PTR(-EBUSY);
3528
3529         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3530         if (!dev)
3531                 return ERR_PTR(-ENOMEM);
3532
3533         if (list_empty(&ffs_devices)) {
3534                 ret = functionfs_init();
3535                 if (ret) {
3536                         kfree(dev);
3537                         return ERR_PTR(ret);
3538                 }
3539         }
3540
3541         list_add(&dev->entry, &ffs_devices);
3542
3543         return dev;
3544 }
3545
3546 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3547 {
3548         struct ffs_dev *existing;
3549         int ret = 0;
3550
3551         ffs_dev_lock();
3552
3553         existing = _ffs_do_find_dev(name);
3554         if (!existing)
3555                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3556         else if (existing != dev)
3557                 ret = -EBUSY;
3558
3559         ffs_dev_unlock();
3560
3561         return ret;
3562 }
3563 EXPORT_SYMBOL_GPL(ffs_name_dev);
3564
3565 int ffs_single_dev(struct ffs_dev *dev)
3566 {
3567         int ret;
3568
3569         ret = 0;
3570         ffs_dev_lock();
3571
3572         if (!list_is_singular(&ffs_devices))
3573                 ret = -EBUSY;
3574         else
3575                 dev->single = true;
3576
3577         ffs_dev_unlock();
3578         return ret;
3579 }
3580 EXPORT_SYMBOL_GPL(ffs_single_dev);
3581
3582 /*
3583  * ffs_lock must be taken by the caller of this function
3584  */
3585 static void _ffs_free_dev(struct ffs_dev *dev)
3586 {
3587         list_del(&dev->entry);
3588
3589         kfree(dev);
3590         if (list_empty(&ffs_devices))
3591                 functionfs_cleanup();
3592 }
3593
3594 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data)
3595 {
3596         int ret = 0;
3597         struct ffs_dev *ffs_dev;
3598
3599         ENTER();
3600         ffs_dev_lock();
3601
3602         ffs_dev = _ffs_find_dev(dev_name);
3603         if (!ffs_dev) {
3604                 ret = -ENOENT;
3605         } else if (ffs_dev->mounted) {
3606                 ret = -EBUSY;
3607         } else if (ffs_dev->ffs_acquire_dev_callback &&
3608                    ffs_dev->ffs_acquire_dev_callback(ffs_dev)) {
3609                 ret = -ENOENT;
3610         } else {
3611                 ffs_dev->mounted = true;
3612                 ffs_dev->ffs_data = ffs_data;
3613                 ffs_data->private_data = ffs_dev;
3614         }
3615
3616         ffs_dev_unlock();
3617         return ret;
3618 }
3619
3620 static void ffs_release_dev(struct ffs_dev *ffs_dev)
3621 {
3622         ENTER();
3623         ffs_dev_lock();
3624
3625         if (ffs_dev && ffs_dev->mounted) {
3626                 ffs_dev->mounted = false;
3627                 if (ffs_dev->ffs_data) {
3628                         ffs_dev->ffs_data->private_data = NULL;
3629                         ffs_dev->ffs_data = NULL;
3630                 }
3631
3632                 if (ffs_dev->ffs_release_dev_callback)
3633                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3634         }
3635
3636         ffs_dev_unlock();
3637 }
3638
3639 static int ffs_ready(struct ffs_data *ffs)
3640 {
3641         struct ffs_dev *ffs_obj;
3642         int ret = 0;
3643
3644         ENTER();
3645         ffs_dev_lock();
3646
3647         ffs_obj = ffs->private_data;
3648         if (!ffs_obj) {
3649                 ret = -EINVAL;
3650                 goto done;
3651         }
3652         if (WARN_ON(ffs_obj->desc_ready)) {
3653                 ret = -EBUSY;
3654                 goto done;
3655         }
3656
3657         ffs_obj->desc_ready = true;
3658
3659         if (ffs_obj->ffs_ready_callback) {
3660                 ret = ffs_obj->ffs_ready_callback(ffs);
3661                 if (ret)
3662                         goto done;
3663         }
3664
3665         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3666 done:
3667         ffs_dev_unlock();
3668         return ret;
3669 }
3670
3671 static void ffs_closed(struct ffs_data *ffs)
3672 {
3673         struct ffs_dev *ffs_obj;
3674         struct f_fs_opts *opts;
3675         struct config_item *ci;
3676
3677         ENTER();
3678         ffs_dev_lock();
3679
3680         ffs_obj = ffs->private_data;
3681         if (!ffs_obj)
3682                 goto done;
3683
3684         ffs_obj->desc_ready = false;
3685
3686         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3687             ffs_obj->ffs_closed_callback)
3688                 ffs_obj->ffs_closed_callback(ffs);
3689
3690         if (ffs_obj->opts)
3691                 opts = ffs_obj->opts;
3692         else
3693                 goto done;
3694
3695         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3696             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3697                 goto done;
3698
3699         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3700         ffs_dev_unlock();
3701
3702         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3703                 unregister_gadget_item(ci);
3704         return;
3705 done:
3706         ffs_dev_unlock();
3707 }
3708
3709 /* Misc helper functions ****************************************************/
3710
3711 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3712 {
3713         return nonblock
3714                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3715                 : mutex_lock_interruptible(mutex);
3716 }
3717
3718 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3719 {
3720         char *data;
3721
3722         if (unlikely(!len))
3723                 return NULL;
3724
3725         data = kmalloc(len, GFP_KERNEL);
3726         if (unlikely(!data))
3727                 return ERR_PTR(-ENOMEM);
3728
3729         if (unlikely(copy_from_user(data, buf, len))) {
3730                 kfree(data);
3731                 return ERR_PTR(-EFAULT);
3732         }
3733
3734         pr_vdebug("Buffer from user space:\n");
3735         ffs_dump_mem("", data, len);
3736
3737         return data;
3738 }
3739
3740 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3741 MODULE_LICENSE("GPL");
3742 MODULE_AUTHOR("Michal Nazarewicz");