drivers/usb/gadget/function/f_fs.c

   1 /*
   2  * f_fs.c -- user mode file system API for USB composite function controllers
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  * Author: Michal Nazarewicz <mina86@mina86.com>
   6  *
   7  * Based on inode.c (GadgetFS) which was:
   8  * Copyright (C) 2003-2004 David Brownell
   9  * Copyright (C) 2003 Agilent Technologies
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  */
  16
  17
  18 /* #define DEBUG */
  19 /* #define VERBOSE_DEBUG */
  20
  21 #include <linux/blkdev.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/export.h>
  24 #include <linux/hid.h>
  25 #include <linux/module.h>
  26 #include <linux/uio.h>
  27 #include <asm/unaligned.h>
  28
  29 #include <linux/usb/composite.h>
  30 #include <linux/usb/functionfs.h>
  31
  32 #include <linux/aio.h>
  33 #include <linux/mmu_context.h>
  34 #include <linux/poll.h>
  35 #include <linux/eventfd.h>
  36
  37 #include "u_fs.h"
  38 #include "u_f.h"
  39 #include "u_os_desc.h"
  40 #include "configfs.h"
  41
  42 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  43
  44 /* Reference counter handling */
  45 static void ffs_data_get(struct ffs_data *ffs);
  46 static void ffs_data_put(struct ffs_data *ffs);
  47 /* Creates new ffs_data object. */
  48 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
  49
  50 /* Opened counter handling. */
  51 static void ffs_data_opened(struct ffs_data *ffs);
  52 static void ffs_data_closed(struct ffs_data *ffs);
  53
  54 /* Called with ffs->mutex held; take over ownership of data. */
  55 static int __must_check
  56 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  57 static int __must_check
  58 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  59
  60
  61 /* The function structure ***************************************************/
  62
  63 struct ffs_ep;
  64
  65 struct ffs_function {
  66         struct usb_configuration        *conf;
  67         struct usb_gadget               *gadget;
  68         struct ffs_data                 *ffs;
  69
  70         struct ffs_ep                   *eps;
  71         u8                              eps_revmap[16];
  72         short                           *interfaces_nums;
  73
  74         struct usb_function             function;
  75 };
  76
  77
  78 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  79 {
  80         return container_of(f, struct ffs_function, function);
  81 }
  82
  83
  84 static inline enum ffs_setup_state
  85 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  86 {
  87         return (enum ffs_setup_state)
  88                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  89 }
  90
  91
  92 static void ffs_func_eps_disable(struct ffs_function *func);
  93 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  94
  95 static int ffs_func_bind(struct usb_configuration *,
  96                          struct usb_function *);
  97 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
  98 static void ffs_func_disable(struct usb_function *);
  99 static int ffs_func_setup(struct usb_function *,
 100                           const struct usb_ctrlrequest *);
 101 static bool ffs_func_req_match(struct usb_function *,
 102                                const struct usb_ctrlrequest *,
 103                                bool config0);
 104 static void ffs_func_suspend(struct usb_function *);
 105 static void ffs_func_resume(struct usb_function *);
 106
 107
 108 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 109 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 110
 111
 112 /* The endpoints structures *************************************************/
 113
 114 struct ffs_ep {
 115         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 116         struct usb_request              *req;   /* P: epfile->mutex */
 117
 118         /* [0]: full speed, [1]: high speed, [2]: super speed */
 119         struct usb_endpoint_descriptor  *descs[3];
 120
 121         u8                              num;
 122
 123         int                             status; /* P: epfile->mutex */
 124 };
 125
 126 struct ffs_epfile {
 127         /* Protects ep->ep and ep->req. */
 128         struct mutex                    mutex;
 129         wait_queue_head_t               wait;
 130
 131         struct ffs_data                 *ffs;
 132         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 133
 134         struct dentry                   *dentry;
 135
 136         /*
 137          * Buffer for holding data from partial reads which may happen since
 138          * we’re rounding user read requests to a multiple of a max packet size.
 139          *
 140          * The pointer is initialised with NULL value and may be set by
 141          * __ffs_epfile_read_data function to point to a temporary buffer.
 142          *
 143          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 144          * data from said buffer and eventually free it.  Importantly, while the
 145          * function is using the buffer, it sets the pointer to NULL.  This is
 146          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 147          * can never run concurrently (they are synchronised by epfile->mutex)
 148          * so the latter will not assign a new value to the pointer.
 149          *
 150          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 151          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 152          * value is crux of the synchronisation between ffs_func_eps_disable and
 153          * __ffs_epfile_read_data.
 154          *
 155          * Once __ffs_epfile_read_data is about to finish it will try to set the
 156          * pointer back to its old value (as described above), but seeing as the
 157          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 158          * the buffer.
 159          *
 160          * == State transitions ==
 161          *
 162          * • ptr == NULL:  (initial state)
 163          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 164          *   ◦ __ffs_epfile_read_buffered:    nop
 165          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 166          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 167          * • ptr == DROP:
 168          *   ◦ __ffs_epfile_read_buffer_free: nop
 169          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 170          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 171          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 172          * • ptr == buf:
 173          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 174          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 175          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 176          *                                    is always called first
 177          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 178          * • ptr == NULL and reading:
 179          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 180          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 181          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 182          *   ◦ reading finishes and …
 183          *     … all data read:               free buf, go to ptr == NULL
 184          *     … otherwise:                   go to ptr == buf and reading
 185          * • ptr == DROP and reading:
 186          *   ◦ __ffs_epfile_read_buffer_free: nop
 187          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 188          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 189          *   ◦ reading finishes:              free buf, go to ptr == DROP
 190          */
 191         struct ffs_buffer               *read_buffer;
 192 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 193
 194         char                            name[5];
 195
 196         unsigned char                   in;     /* P: ffs->eps_lock */
 197         unsigned char                   isoc;   /* P: ffs->eps_lock */
 198
 199         unsigned char                   _pad;
 200 };
 201
 202 struct ffs_buffer {
 203         size_t length;
 204         char *data;
 205         char storage[];
 206 };
 207
 208 /*  ffs_io_data structure ***************************************************/
 209
 210 struct ffs_io_data {
 211         bool aio;
 212         bool read;
 213
 214         struct kiocb *kiocb;
 215         struct iov_iter data;
 216         const void *to_free;
 217         char *buf;
 218
 219         struct mm_struct *mm;
 220         struct work_struct work;
 221
 222         struct usb_ep *ep;
 223         struct usb_request *req;
 224
 225         struct ffs_data *ffs;
 226 };
 227
 228 struct ffs_desc_helper {
 229         struct ffs_data *ffs;
 230         unsigned interfaces_count;
 231         unsigned eps_count;
 232 };
 233
 234 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 235 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 236
 237 static struct dentry *
 238 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 239                    const struct file_operations *fops);
 240
 241 /* Devices management *******************************************************/
 242
 243 DEFINE_MUTEX(ffs_lock);
 244 EXPORT_SYMBOL_GPL(ffs_lock);
 245
 246 static struct ffs_dev *_ffs_find_dev(const char *name);
 247 static struct ffs_dev *_ffs_alloc_dev(void);
 248 static int _ffs_name_dev(struct ffs_dev *dev, const char *name);
 249 static void _ffs_free_dev(struct ffs_dev *dev);
 250 static void *ffs_acquire_dev(const char *dev_name);
 251 static void ffs_release_dev(struct ffs_data *ffs_data);
 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_all(&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 0;
 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                 use_mm(io_data->mm);
 763                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 764                 unuse_mm(io_data->mm);
 765         }
 766
 767         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 768
 769         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 770                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 771
 772         usb_ep_free_request(io_data->ep, io_data->req);
 773
 774         if (io_data->read)
 775                 kfree(io_data->to_free);
 776         kfree(io_data->buf);
 777         kfree(io_data);
 778 }
 779
 780 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 781                                          struct usb_request *req)
 782 {
 783         struct ffs_io_data *io_data = req->context;
 784
 785         ENTER();
 786
 787         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 788         schedule_work(&io_data->work);
 789 }
 790
 791 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 792 {
 793         /*
 794          * See comment in struct ffs_epfile for full read_buffer pointer
 795          * synchronisation story.
 796          */
 797         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 798         if (buf && buf != READ_BUFFER_DROP)
 799                 kfree(buf);
 800 }
 801
 802 /* Assumes epfile->mutex is held. */
 803 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 804                                           struct iov_iter *iter)
 805 {
 806         /*
 807          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 808          * the buffer while we are using it.  See comment in struct ffs_epfile
 809          * for full read_buffer pointer synchronisation story.
 810          */
 811         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 812         ssize_t ret;
 813         if (!buf || buf == READ_BUFFER_DROP)
 814                 return 0;
 815
 816         ret = copy_to_iter(buf->data, buf->length, iter);
 817         if (buf->length == ret) {
 818                 kfree(buf);
 819                 return ret;
 820         }
 821
 822         if (unlikely(iov_iter_count(iter))) {
 823                 ret = -EFAULT;
 824         } else {
 825                 buf->length -= ret;
 826                 buf->data += ret;
 827         }
 828
 829         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 830                 kfree(buf);
 831
 832         return ret;
 833 }
 834
 835 /* Assumes epfile->mutex is held. */
 836 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 837                                       void *data, int data_len,
 838                                       struct iov_iter *iter)
 839 {
 840         struct ffs_buffer *buf;
 841
 842         ssize_t ret = copy_to_iter(data, data_len, iter);
 843         if (likely(data_len == ret))
 844                 return ret;
 845
 846         if (unlikely(iov_iter_count(iter)))
 847                 return -EFAULT;
 848
 849         /* See ffs_copy_to_iter for more context. */
 850         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 851                 data_len, ret);
 852
 853         data_len -= ret;
 854         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 855         if (!buf)
 856                 return -ENOMEM;
 857         buf->length = data_len;
 858         buf->data = buf->storage;
 859         memcpy(buf->storage, data + ret, data_len);
 860
 861         /*
 862          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 863          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 864          * in struct ffs_epfile for full read_buffer pointer synchronisation
 865          * story.
 866          */
 867         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 868                 kfree(buf);
 869
 870         return ret;
 871 }
 872
 873 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 874 {
 875         struct ffs_epfile *epfile = file->private_data;
 876         struct usb_request *req;
 877         struct ffs_ep *ep;
 878         char *data = NULL;
 879         ssize_t ret, data_len = -EINVAL;
 880         int halt;
 881
 882         /* Are we still active? */
 883         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 884                 return -ENODEV;
 885
 886         /* Wait for endpoint to be enabled */
 887         ep = epfile->ep;
 888         if (!ep) {
 889                 if (file->f_flags & O_NONBLOCK)
 890                         return -EAGAIN;
 891
 892                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
 893                 if (ret)
 894                         return -EINTR;
 895         }
 896
 897         /* Do we halt? */
 898         halt = (!io_data->read == !epfile->in);
 899         if (halt && epfile->isoc)
 900                 return -EINVAL;
 901
 902         /* We will be using request and read_buffer */
 903         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 904         if (unlikely(ret))
 905                 goto error;
 906
 907         /* Allocate & copy */
 908         if (!halt) {
 909                 struct usb_gadget *gadget;
 910
 911                 /*
 912                  * Do we have buffered data from previous partial read?  Check
 913                  * that for synchronous case only because we do not have
 914                  * facility to ‘wake up’ a pending asynchronous read and push
 915                  * buffered data to it which we would need to make things behave
 916                  * consistently.
 917                  */
 918                 if (!io_data->aio && io_data->read) {
 919                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 920                         if (ret)
 921                                 goto error_mutex;
 922                 }
 923
 924                 /*
 925                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 926                  * before the waiting completes, so do not assign to 'gadget'
 927                  * earlier
 928                  */
 929                 gadget = epfile->ffs->gadget;
 930
 931                 spin_lock_irq(&epfile->ffs->eps_lock);
 932                 /* In the meantime, endpoint got disabled or changed. */
 933                 if (epfile->ep != ep) {
 934                         ret = -ESHUTDOWN;
 935                         goto error_lock;
 936                 }
 937                 data_len = iov_iter_count(&io_data->data);
 938                 /*
 939                  * Controller may require buffer size to be aligned to
 940                  * maxpacketsize of an out endpoint.
 941                  */
 942                 if (io_data->read)
 943                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
 944                 spin_unlock_irq(&epfile->ffs->eps_lock);
 945
 946                 data = kmalloc(data_len, GFP_KERNEL);
 947                 if (unlikely(!data)) {
 948                         ret = -ENOMEM;
 949                         goto error_mutex;
 950                 }
 951                 if (!io_data->read &&
 952                     copy_from_iter(data, data_len, &io_data->data) != data_len) {
 953                         ret = -EFAULT;
 954                         goto error_mutex;
 955                 }
 956         }
 957
 958         spin_lock_irq(&epfile->ffs->eps_lock);
 959
 960         if (epfile->ep != ep) {
 961                 /* In the meantime, endpoint got disabled or changed. */
 962                 ret = -ESHUTDOWN;
 963         } else if (halt) {
 964                 /* Halt */
 965                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 966                         usb_ep_set_halt(ep->ep);
 967                 ret = -EBADMSG;
 968         } else if (unlikely(data_len == -EINVAL)) {
 969                 /*
 970                  * Sanity Check: even though data_len can't be used
 971                  * uninitialized at the time I write this comment, some
 972                  * compilers complain about this situation.
 973                  * In order to keep the code clean from warnings, data_len is
 974                  * being initialized to -EINVAL during its declaration, which
 975                  * means we can't rely on compiler anymore to warn no future
 976                  * changes won't result in data_len being used uninitialized.
 977                  * For such reason, we're adding this redundant sanity check
 978                  * here.
 979                  */
 980                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
 981                 ret = -EINVAL;
 982         } else if (!io_data->aio) {
 983                 DECLARE_COMPLETION_ONSTACK(done);
 984                 bool interrupted = false;
 985
 986                 req = ep->req;
 987                 req->buf      = data;
 988                 req->length   = data_len;
 989
 990                 req->context  = &done;
 991                 req->complete = ffs_epfile_io_complete;
 992
 993                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 994                 if (unlikely(ret < 0))
 995                         goto error_lock;
 996
 997                 spin_unlock_irq(&epfile->ffs->eps_lock);
 998
 999                 if (unlikely(wait_for_completion_interruptible(&done))) {
1000                         /*
1001                          * To avoid race condition with ffs_epfile_io_complete,
1002                          * dequeue the request first then check
1003                          * status. usb_ep_dequeue API should guarantee no race
1004                          * condition with req->complete callback.
1005                          */
1006                         usb_ep_dequeue(ep->ep, req);
1007                         interrupted = ep->status < 0;
1008                 }
1009
1010                 if (interrupted)
1011                         ret = -EINTR;
1012                 else if (io_data->read && ep->status > 0)
1013                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1014                                                      &io_data->data);
1015                 else
1016                         ret = ep->status;
1017                 goto error_mutex;
1018         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_KERNEL))) {
1019                 ret = -ENOMEM;
1020         } else {
1021                 req->buf      = data;
1022                 req->length   = data_len;
1023
1024                 io_data->buf = data;
1025                 io_data->ep = ep->ep;
1026                 io_data->req = req;
1027                 io_data->ffs = epfile->ffs;
1028
1029                 req->context  = io_data;
1030                 req->complete = ffs_epfile_async_io_complete;
1031
1032                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1033                 if (unlikely(ret)) {
1034                         usb_ep_free_request(ep->ep, req);
1035                         goto error_lock;
1036                 }
1037
1038                 ret = -EIOCBQUEUED;
1039                 /*
1040                  * Do not kfree the buffer in this function.  It will be freed
1041                  * by ffs_user_copy_worker.
1042                  */
1043                 data = NULL;
1044         }
1045
1046 error_lock:
1047         spin_unlock_irq(&epfile->ffs->eps_lock);
1048 error_mutex:
1049         mutex_unlock(&epfile->mutex);
1050 error:
1051         kfree(data);
1052         return ret;
1053 }
1054
1055 static int
1056 ffs_epfile_open(struct inode *inode, struct file *file)
1057 {
1058         struct ffs_epfile *epfile = inode->i_private;
1059
1060         ENTER();
1061
1062         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1063                 return -ENODEV;
1064
1065         file->private_data = epfile;
1066         ffs_data_opened(epfile->ffs);
1067
1068         return 0;
1069 }
1070
1071 static int ffs_aio_cancel(struct kiocb *kiocb)
1072 {
1073         struct ffs_io_data *io_data = kiocb->private;
1074         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1075         int value;
1076
1077         ENTER();
1078
1079         spin_lock_irq(&epfile->ffs->eps_lock);
1080
1081         if (likely(io_data && io_data->ep && io_data->req))
1082                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1083         else
1084                 value = -EINVAL;
1085
1086         spin_unlock_irq(&epfile->ffs->eps_lock);
1087
1088         return value;
1089 }
1090
1091 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1092 {
1093         struct ffs_io_data io_data, *p = &io_data;
1094         ssize_t res;
1095
1096         ENTER();
1097
1098         if (!is_sync_kiocb(kiocb)) {
1099                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1100                 if (unlikely(!p))
1101                         return -ENOMEM;
1102                 p->aio = true;
1103         } else {
1104                 p->aio = false;
1105         }
1106
1107         p->read = false;
1108         p->kiocb = kiocb;
1109         p->data = *from;
1110         p->mm = current->mm;
1111
1112         kiocb->private = p;
1113
1114         if (p->aio)
1115                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1116
1117         res = ffs_epfile_io(kiocb->ki_filp, p);
1118         if (res == -EIOCBQUEUED)
1119                 return res;
1120         if (p->aio)
1121                 kfree(p);
1122         else
1123                 *from = p->data;
1124         return res;
1125 }
1126
1127 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1128 {
1129         struct ffs_io_data io_data, *p = &io_data;
1130         ssize_t res;
1131
1132         ENTER();
1133
1134         if (!is_sync_kiocb(kiocb)) {
1135                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1136                 if (unlikely(!p))
1137                         return -ENOMEM;
1138                 p->aio = true;
1139         } else {
1140                 p->aio = false;
1141         }
1142
1143         p->read = true;
1144         p->kiocb = kiocb;
1145         if (p->aio) {
1146                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1147                 if (!p->to_free) {
1148                         kfree(p);
1149                         return -ENOMEM;
1150                 }
1151         } else {
1152                 p->data = *to;
1153                 p->to_free = NULL;
1154         }
1155         p->mm = current->mm;
1156
1157         kiocb->private = p;
1158
1159         if (p->aio)
1160                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1161
1162         res = ffs_epfile_io(kiocb->ki_filp, p);
1163         if (res == -EIOCBQUEUED)
1164                 return res;
1165
1166         if (p->aio) {
1167                 kfree(p->to_free);
1168                 kfree(p);
1169         } else {
1170                 *to = p->data;
1171         }
1172         return res;
1173 }
1174
1175 static int
1176 ffs_epfile_release(struct inode *inode, struct file *file)
1177 {
1178         struct ffs_epfile *epfile = inode->i_private;
1179
1180         ENTER();
1181
1182         __ffs_epfile_read_buffer_free(epfile);
1183         ffs_data_closed(epfile->ffs);
1184
1185         return 0;
1186 }
1187
1188 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1189                              unsigned long value)
1190 {
1191         struct ffs_epfile *epfile = file->private_data;
1192         int ret;
1193
1194         ENTER();
1195
1196         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1197                 return -ENODEV;
1198
1199         spin_lock_irq(&epfile->ffs->eps_lock);
1200         if (likely(epfile->ep)) {
1201                 switch (code) {
1202                 case FUNCTIONFS_FIFO_STATUS:
1203                         ret = usb_ep_fifo_status(epfile->ep->ep);
1204                         break;
1205                 case FUNCTIONFS_FIFO_FLUSH:
1206                         usb_ep_fifo_flush(epfile->ep->ep);
1207                         ret = 0;
1208                         break;
1209                 case FUNCTIONFS_CLEAR_HALT:
1210                         ret = usb_ep_clear_halt(epfile->ep->ep);
1211                         break;
1212                 case FUNCTIONFS_ENDPOINT_REVMAP:
1213                         ret = epfile->ep->num;
1214                         break;
1215                 case FUNCTIONFS_ENDPOINT_DESC:
1216                 {
1217                         int desc_idx;
1218                         struct usb_endpoint_descriptor *desc;
1219
1220                         switch (epfile->ffs->gadget->speed) {
1221                         case USB_SPEED_SUPER:
1222                                 desc_idx = 2;
1223                                 break;
1224                         case USB_SPEED_HIGH:
1225                                 desc_idx = 1;
1226                                 break;
1227                         default:
1228                                 desc_idx = 0;
1229                         }
1230                         desc = epfile->ep->descs[desc_idx];
1231
1232                         spin_unlock_irq(&epfile->ffs->eps_lock);
1233                         ret = copy_to_user((void *)value, desc, sizeof(*desc));
1234                         if (ret)
1235                                 ret = -EFAULT;
1236                         return ret;
1237                 }
1238                 default:
1239                         ret = -ENOTTY;
1240                 }
1241         } else {
1242                 ret = -ENODEV;
1243         }
1244         spin_unlock_irq(&epfile->ffs->eps_lock);
1245
1246         return ret;
1247 }
1248
1249 static const struct file_operations ffs_epfile_operations = {
1250         .llseek =       no_llseek,
1251
1252         .open =         ffs_epfile_open,
1253         .write_iter =   ffs_epfile_write_iter,
1254         .read_iter =    ffs_epfile_read_iter,
1255         .release =      ffs_epfile_release,
1256         .unlocked_ioctl =       ffs_epfile_ioctl,
1257 };
1258
1259
1260 /* File system and super block operations ***********************************/
1261
1262 /*
1263  * Mounting the file system creates a controller file, used first for
1264  * function configuration then later for event monitoring.
1265  */
1266
1267 static struct inode *__must_check
1268 ffs_sb_make_inode(struct super_block *sb, void *data,
1269                   const struct file_operations *fops,
1270                   const struct inode_operations *iops,
1271                   struct ffs_file_perms *perms)
1272 {
1273         struct inode *inode;
1274
1275         ENTER();
1276
1277         inode = new_inode(sb);
1278
1279         if (likely(inode)) {
1280                 struct timespec ts = current_time(inode);
1281
1282                 inode->i_ino     = get_next_ino();
1283                 inode->i_mode    = perms->mode;
1284                 inode->i_uid     = perms->uid;
1285                 inode->i_gid     = perms->gid;
1286                 inode->i_atime   = ts;
1287                 inode->i_mtime   = ts;
1288                 inode->i_ctime   = ts;
1289                 inode->i_private = data;
1290                 if (fops)
1291                         inode->i_fop = fops;
1292                 if (iops)
1293                         inode->i_op  = iops;
1294         }
1295
1296         return inode;
1297 }
1298
1299 /* Create "regular" file */
1300 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1301                                         const char *name, void *data,
1302                                         const struct file_operations *fops)
1303 {
1304         struct ffs_data *ffs = sb->s_fs_info;
1305         struct dentry   *dentry;
1306         struct inode    *inode;
1307
1308         ENTER();
1309
1310         dentry = d_alloc_name(sb->s_root, name);
1311         if (unlikely(!dentry))
1312                 return NULL;
1313
1314         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1315         if (unlikely(!inode)) {
1316                 dput(dentry);
1317                 return NULL;
1318         }
1319
1320         d_add(dentry, inode);
1321         return dentry;
1322 }
1323
1324 /* Super block */
1325 static const struct super_operations ffs_sb_operations = {
1326         .statfs =       simple_statfs,
1327         .drop_inode =   generic_delete_inode,
1328 };
1329
1330 struct ffs_sb_fill_data {
1331         struct ffs_file_perms perms;
1332         umode_t root_mode;
1333         const char *dev_name;
1334         bool no_disconnect;
1335         struct ffs_data *ffs_data;
1336 };
1337
1338 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1339 {
1340         struct ffs_sb_fill_data *data = _data;
1341         struct inode    *inode;
1342         struct ffs_data *ffs = data->ffs_data;
1343
1344         ENTER();
1345
1346         ffs->sb              = sb;
1347         data->ffs_data       = NULL;
1348         sb->s_fs_info        = ffs;
1349         sb->s_blocksize      = PAGE_SIZE;
1350         sb->s_blocksize_bits = PAGE_SHIFT;
1351         sb->s_magic          = FUNCTIONFS_MAGIC;
1352         sb->s_op             = &ffs_sb_operations;
1353         sb->s_time_gran      = 1;
1354
1355         /* Root inode */
1356         data->perms.mode = data->root_mode;
1357         inode = ffs_sb_make_inode(sb, NULL,
1358                                   &simple_dir_operations,
1359                                   &simple_dir_inode_operations,
1360                                   &data->perms);
1361         sb->s_root = d_make_root(inode);
1362         if (unlikely(!sb->s_root))
1363                 return -ENOMEM;
1364
1365         /* EP0 file */
1366         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1367                                          &ffs_ep0_operations)))
1368                 return -ENOMEM;
1369
1370         return 0;
1371 }
1372
1373 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1374 {
1375         ENTER();
1376
1377         if (!opts || !*opts)
1378                 return 0;
1379
1380         for (;;) {
1381                 unsigned long value;
1382                 char *eq, *comma;
1383
1384                 /* Option limit */
1385                 comma = strchr(opts, ',');
1386                 if (comma)
1387                         *comma = 0;
1388
1389                 /* Value limit */
1390                 eq = strchr(opts, '=');
1391                 if (unlikely(!eq)) {
1392                         pr_err("'=' missing in %s\n", opts);
1393                         return -EINVAL;
1394                 }
1395                 *eq = 0;
1396
1397                 /* Parse value */
1398                 if (kstrtoul(eq + 1, 0, &value)) {
1399                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1400                         return -EINVAL;
1401                 }
1402
1403                 /* Interpret option */
1404                 switch (eq - opts) {
1405                 case 13:
1406                         if (!memcmp(opts, "no_disconnect", 13))
1407                                 data->no_disconnect = !!value;
1408                         else
1409                                 goto invalid;
1410                         break;
1411                 case 5:
1412                         if (!memcmp(opts, "rmode", 5))
1413                                 data->root_mode  = (value & 0555) | S_IFDIR;
1414                         else if (!memcmp(opts, "fmode", 5))
1415                                 data->perms.mode = (value & 0666) | S_IFREG;
1416                         else
1417                                 goto invalid;
1418                         break;
1419
1420                 case 4:
1421                         if (!memcmp(opts, "mode", 4)) {
1422                                 data->root_mode  = (value & 0555) | S_IFDIR;
1423                                 data->perms.mode = (value & 0666) | S_IFREG;
1424                         } else {
1425                                 goto invalid;
1426                         }
1427                         break;
1428
1429                 case 3:
1430                         if (!memcmp(opts, "uid", 3)) {
1431                                 data->perms.uid = make_kuid(current_user_ns(), value);
1432                                 if (!uid_valid(data->perms.uid)) {
1433                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1434                                         return -EINVAL;
1435                                 }
1436                         } else if (!memcmp(opts, "gid", 3)) {
1437                                 data->perms.gid = make_kgid(current_user_ns(), value);
1438                                 if (!gid_valid(data->perms.gid)) {
1439                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1440                                         return -EINVAL;
1441                                 }
1442                         } else {
1443                                 goto invalid;
1444                         }
1445                         break;
1446
1447                 default:
1448 invalid:
1449                         pr_err("%s: invalid option\n", opts);
1450                         return -EINVAL;
1451                 }
1452
1453                 /* Next iteration */
1454                 if (!comma)
1455                         break;
1456                 opts = comma + 1;
1457         }
1458
1459         return 0;
1460 }
1461
1462 /* "mount -t functionfs dev_name /dev/function" ends up here */
1463
1464 static struct dentry *
1465 ffs_fs_mount(struct file_system_type *t, int flags,
1466               const char *dev_name, void *opts)
1467 {
1468         struct ffs_sb_fill_data data = {
1469                 .perms = {
1470                         .mode = S_IFREG | 0600,
1471                         .uid = GLOBAL_ROOT_UID,
1472                         .gid = GLOBAL_ROOT_GID,
1473                 },
1474                 .root_mode = S_IFDIR | 0500,
1475                 .no_disconnect = false,
1476         };
1477         struct dentry *rv;
1478         int ret;
1479         void *ffs_dev;
1480         struct ffs_data *ffs;
1481
1482         ENTER();
1483
1484         ret = ffs_fs_parse_opts(&data, opts);
1485         if (unlikely(ret < 0))
1486                 return ERR_PTR(ret);
1487
1488         ffs = ffs_data_new();
1489         if (unlikely(!ffs))
1490                 return ERR_PTR(-ENOMEM);
1491         ffs->file_perms = data.perms;
1492         ffs->no_disconnect = data.no_disconnect;
1493
1494         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1495         if (unlikely(!ffs->dev_name)) {
1496                 ffs_data_put(ffs);
1497                 return ERR_PTR(-ENOMEM);
1498         }
1499
1500         ffs_dev = ffs_acquire_dev(dev_name);
1501         if (IS_ERR(ffs_dev)) {
1502                 ffs_data_put(ffs);
1503                 return ERR_CAST(ffs_dev);
1504         }
1505         ffs->private_data = ffs_dev;
1506         data.ffs_data = ffs;
1507
1508         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1509         if (IS_ERR(rv) && data.ffs_data) {
1510                 ffs_release_dev(data.ffs_data);
1511                 ffs_data_put(data.ffs_data);
1512         }
1513         return rv;
1514 }
1515
1516 static void
1517 ffs_fs_kill_sb(struct super_block *sb)
1518 {
1519         ENTER();
1520
1521         kill_litter_super(sb);
1522         if (sb->s_fs_info) {
1523                 ffs_release_dev(sb->s_fs_info);
1524                 ffs_data_closed(sb->s_fs_info);
1525                 ffs_data_put(sb->s_fs_info);
1526         }
1527 }
1528
1529 static struct file_system_type ffs_fs_type = {
1530         .owner          = THIS_MODULE,
1531         .name           = "functionfs",
1532         .mount          = ffs_fs_mount,
1533         .kill_sb        = ffs_fs_kill_sb,
1534 };
1535 MODULE_ALIAS_FS("functionfs");
1536
1537
1538 /* Driver's main init/cleanup functions *************************************/
1539
1540 static int functionfs_init(void)
1541 {
1542         int ret;
1543
1544         ENTER();
1545
1546         ret = register_filesystem(&ffs_fs_type);
1547         if (likely(!ret))
1548                 pr_info("file system registered\n");
1549         else
1550                 pr_err("failed registering file system (%d)\n", ret);
1551
1552         return ret;
1553 }
1554
1555 static void functionfs_cleanup(void)
1556 {
1557         ENTER();
1558
1559         pr_info("unloading\n");
1560         unregister_filesystem(&ffs_fs_type);
1561 }
1562
1563
1564 /* ffs_data and ffs_function construction and destruction code **************/
1565
1566 static void ffs_data_clear(struct ffs_data *ffs);
1567 static void ffs_data_reset(struct ffs_data *ffs);
1568
1569 static void ffs_data_get(struct ffs_data *ffs)
1570 {
1571         ENTER();
1572
1573         atomic_inc(&ffs->ref);
1574 }
1575
1576 static void ffs_data_opened(struct ffs_data *ffs)
1577 {
1578         ENTER();
1579
1580         atomic_inc(&ffs->ref);
1581         if (atomic_add_return(1, &ffs->opened) == 1 &&
1582                         ffs->state == FFS_DEACTIVATED) {
1583                 ffs->state = FFS_CLOSING;
1584                 ffs_data_reset(ffs);
1585         }
1586 }
1587
1588 static void ffs_data_put(struct ffs_data *ffs)
1589 {
1590         ENTER();
1591
1592         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1593                 pr_info("%s(): freeing\n", __func__);
1594                 ffs_data_clear(ffs);
1595                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1596                        waitqueue_active(&ffs->ep0req_completion.wait));
1597                 kfree(ffs->dev_name);
1598                 kfree(ffs);
1599         }
1600 }
1601
1602 static void ffs_data_closed(struct ffs_data *ffs)
1603 {
1604         ENTER();
1605
1606         if (atomic_dec_and_test(&ffs->opened)) {
1607                 if (ffs->no_disconnect) {
1608                         ffs->state = FFS_DEACTIVATED;
1609                         if (ffs->epfiles) {
1610                                 ffs_epfiles_destroy(ffs->epfiles,
1611                                                    ffs->eps_count);
1612                                 ffs->epfiles = NULL;
1613                         }
1614                         if (ffs->setup_state == FFS_SETUP_PENDING)
1615                                 __ffs_ep0_stall(ffs);
1616                 } else {
1617                         ffs->state = FFS_CLOSING;
1618                         ffs_data_reset(ffs);
1619                 }
1620         }
1621         if (atomic_read(&ffs->opened) < 0) {
1622                 ffs->state = FFS_CLOSING;
1623                 ffs_data_reset(ffs);
1624         }
1625
1626         ffs_data_put(ffs);
1627 }
1628
1629 static struct ffs_data *ffs_data_new(void)
1630 {
1631         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1632         if (unlikely(!ffs))
1633                 return NULL;
1634
1635         ENTER();
1636
1637         atomic_set(&ffs->ref, 1);
1638         atomic_set(&ffs->opened, 0);
1639         ffs->state = FFS_READ_DESCRIPTORS;
1640         mutex_init(&ffs->mutex);
1641         spin_lock_init(&ffs->eps_lock);
1642         init_waitqueue_head(&ffs->ev.waitq);
1643         init_completion(&ffs->ep0req_completion);
1644
1645         /* XXX REVISIT need to update it in some places, or do we? */
1646         ffs->ev.can_stall = 1;
1647
1648         return ffs;
1649 }
1650
1651 static void ffs_data_clear(struct ffs_data *ffs)
1652 {
1653         ENTER();
1654
1655         ffs_closed(ffs);
1656
1657         BUG_ON(ffs->gadget);
1658
1659         if (ffs->epfiles)
1660                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1661
1662         if (ffs->ffs_eventfd)
1663                 eventfd_ctx_put(ffs->ffs_eventfd);
1664
1665         kfree(ffs->raw_descs_data);
1666         kfree(ffs->raw_strings);
1667         kfree(ffs->stringtabs);
1668 }
1669
1670 static void ffs_data_reset(struct ffs_data *ffs)
1671 {
1672         ENTER();
1673
1674         ffs_data_clear(ffs);
1675
1676         ffs->epfiles = NULL;
1677         ffs->raw_descs_data = NULL;
1678         ffs->raw_descs = NULL;
1679         ffs->raw_strings = NULL;
1680         ffs->stringtabs = NULL;
1681
1682         ffs->raw_descs_length = 0;
1683         ffs->fs_descs_count = 0;
1684         ffs->hs_descs_count = 0;
1685         ffs->ss_descs_count = 0;
1686
1687         ffs->strings_count = 0;
1688         ffs->interfaces_count = 0;
1689         ffs->eps_count = 0;
1690
1691         ffs->ev.count = 0;
1692
1693         ffs->state = FFS_READ_DESCRIPTORS;
1694         ffs->setup_state = FFS_NO_SETUP;
1695         ffs->flags = 0;
1696 }
1697
1698
1699 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1700 {
1701         struct usb_gadget_strings **lang;
1702         int first_id;
1703
1704         ENTER();
1705
1706         if (WARN_ON(ffs->state != FFS_ACTIVE
1707                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1708                 return -EBADFD;
1709
1710         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1711         if (unlikely(first_id < 0))
1712                 return first_id;
1713
1714         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1715         if (unlikely(!ffs->ep0req))
1716                 return -ENOMEM;
1717         ffs->ep0req->complete = ffs_ep0_complete;
1718         ffs->ep0req->context = ffs;
1719
1720         lang = ffs->stringtabs;
1721         if (lang) {
1722                 for (; *lang; ++lang) {
1723                         struct usb_string *str = (*lang)->strings;
1724                         int id = first_id;
1725                         for (; str->s; ++id, ++str)
1726                                 str->id = id;
1727                 }
1728         }
1729
1730         ffs->gadget = cdev->gadget;
1731         ffs_data_get(ffs);
1732         return 0;
1733 }
1734
1735 static void functionfs_unbind(struct ffs_data *ffs)
1736 {
1737         ENTER();
1738
1739         if (!WARN_ON(!ffs->gadget)) {
1740                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1741                 ffs->ep0req = NULL;
1742                 ffs->gadget = NULL;
1743                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1744                 ffs_data_put(ffs);
1745         }
1746 }
1747
1748 static int ffs_epfiles_create(struct ffs_data *ffs)
1749 {
1750         struct ffs_epfile *epfile, *epfiles;
1751         unsigned i, count;
1752
1753         ENTER();
1754
1755         count = ffs->eps_count;
1756         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1757         if (!epfiles)
1758                 return -ENOMEM;
1759
1760         epfile = epfiles;
1761         for (i = 1; i <= count; ++i, ++epfile) {
1762                 epfile->ffs = ffs;
1763                 mutex_init(&epfile->mutex);
1764                 init_waitqueue_head(&epfile->wait);
1765                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1766                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1767                 else
1768                         sprintf(epfile->name, "ep%u", i);
1769                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1770                                                  epfile,
1771                                                  &ffs_epfile_operations);
1772                 if (unlikely(!epfile->dentry)) {
1773                         ffs_epfiles_destroy(epfiles, i - 1);
1774                         return -ENOMEM;
1775                 }
1776         }
1777
1778         ffs->epfiles = epfiles;
1779         return 0;
1780 }
1781
1782 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1783 {
1784         struct ffs_epfile *epfile = epfiles;
1785
1786         ENTER();
1787
1788         for (; count; --count, ++epfile) {
1789                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1790                        waitqueue_active(&epfile->wait));
1791                 if (epfile->dentry) {
1792                         d_delete(epfile->dentry);
1793                         dput(epfile->dentry);
1794                         epfile->dentry = NULL;
1795                 }
1796         }
1797
1798         kfree(epfiles);
1799 }
1800
1801 static void ffs_func_eps_disable(struct ffs_function *func)
1802 {
1803         struct ffs_ep *ep         = func->eps;
1804         struct ffs_epfile *epfile = func->ffs->epfiles;
1805         unsigned count            = func->ffs->eps_count;
1806         unsigned long flags;
1807
1808         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1809         do {
1810                 /* pending requests get nuked */
1811                 if (likely(ep->ep))
1812                         usb_ep_disable(ep->ep);
1813                 ++ep;
1814
1815                 if (epfile) {
1816                         epfile->ep = NULL;
1817                         __ffs_epfile_read_buffer_free(epfile);
1818                         ++epfile;
1819                 }
1820         } while (--count);
1821         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1822 }
1823
1824 static int ffs_func_eps_enable(struct ffs_function *func)
1825 {
1826         struct ffs_data *ffs      = func->ffs;
1827         struct ffs_ep *ep         = func->eps;
1828         struct ffs_epfile *epfile = ffs->epfiles;
1829         unsigned count            = ffs->eps_count;
1830         unsigned long flags;
1831         int ret = 0;
1832
1833         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1834         do {
1835                 struct usb_endpoint_descriptor *ds;
1836                 int desc_idx;
1837
1838                 if (ffs->gadget->speed == USB_SPEED_SUPER)
1839                         desc_idx = 2;
1840                 else if (ffs->gadget->speed == USB_SPEED_HIGH)
1841                         desc_idx = 1;
1842                 else
1843                         desc_idx = 0;
1844
1845                 /* fall-back to lower speed if desc missing for current speed */
1846                 do {
1847                         ds = ep->descs[desc_idx];
1848                 } while (!ds && --desc_idx >= 0);
1849
1850                 if (!ds) {
1851                         ret = -EINVAL;
1852                         break;
1853                 }
1854
1855                 ep->ep->driver_data = ep;
1856                 ep->ep->desc = ds;
1857                 ret = usb_ep_enable(ep->ep);
1858                 if (likely(!ret)) {
1859                         epfile->ep = ep;
1860                         epfile->in = usb_endpoint_dir_in(ds);
1861                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1862                 } else {
1863                         break;
1864                 }
1865
1866                 wake_up(&epfile->wait);
1867
1868                 ++ep;
1869                 ++epfile;
1870         } while (--count);
1871         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1872
1873         return ret;
1874 }
1875
1876
1877 /* Parsing and building descriptors and strings *****************************/
1878
1879 /*
1880  * This validates if data pointed by data is a valid USB descriptor as
1881  * well as record how many interfaces, endpoints and strings are
1882  * required by given configuration.  Returns address after the
1883  * descriptor or NULL if data is invalid.
1884  */
1885
1886 enum ffs_entity_type {
1887         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1888 };
1889
1890 enum ffs_os_desc_type {
1891         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1892 };
1893
1894 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1895                                    u8 *valuep,
1896                                    struct usb_descriptor_header *desc,
1897                                    void *priv);
1898
1899 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1900                                     struct usb_os_desc_header *h, void *data,
1901                                     unsigned len, void *priv);
1902
1903 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1904                                            ffs_entity_callback entity,
1905                                            void *priv)
1906 {
1907         struct usb_descriptor_header *_ds = (void *)data;
1908         u8 length;
1909         int ret;
1910
1911         ENTER();
1912
1913         /* At least two bytes are required: length and type */
1914         if (len < 2) {
1915                 pr_vdebug("descriptor too short\n");
1916                 return -EINVAL;
1917         }
1918
1919         /* If we have at least as many bytes as the descriptor takes? */
1920         length = _ds->bLength;
1921         if (len < length) {
1922                 pr_vdebug("descriptor longer then available data\n");
1923                 return -EINVAL;
1924         }
1925
1926 #define __entity_check_INTERFACE(val)  1
1927 #define __entity_check_STRING(val)     (val)
1928 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1929 #define __entity(type, val) do {                                        \
1930                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1931                 if (unlikely(!__entity_check_ ##type(val))) {           \
1932                         pr_vdebug("invalid entity's value\n");          \
1933                         return -EINVAL;                                 \
1934                 }                                                       \
1935                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1936                 if (unlikely(ret < 0)) {                                \
1937                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1938                                  (val), ret);                           \
1939                         return ret;                                     \
1940                 }                                                       \
1941         } while (0)
1942
1943         /* Parse descriptor depending on type. */
1944         switch (_ds->bDescriptorType) {
1945         case USB_DT_DEVICE:
1946         case USB_DT_CONFIG:
1947         case USB_DT_STRING:
1948         case USB_DT_DEVICE_QUALIFIER:
1949                 /* function can't have any of those */
1950                 pr_vdebug("descriptor reserved for gadget: %d\n",
1951                       _ds->bDescriptorType);
1952                 return -EINVAL;
1953
1954         case USB_DT_INTERFACE: {
1955                 struct usb_interface_descriptor *ds = (void *)_ds;
1956                 pr_vdebug("interface descriptor\n");
1957                 if (length != sizeof *ds)
1958                         goto inv_length;
1959
1960                 __entity(INTERFACE, ds->bInterfaceNumber);
1961                 if (ds->iInterface)
1962                         __entity(STRING, ds->iInterface);
1963         }
1964                 break;
1965
1966         case USB_DT_ENDPOINT: {
1967                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1968                 pr_vdebug("endpoint descriptor\n");
1969                 if (length != USB_DT_ENDPOINT_SIZE &&
1970                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1971                         goto inv_length;
1972                 __entity(ENDPOINT, ds->bEndpointAddress);
1973         }
1974                 break;
1975
1976         case HID_DT_HID:
1977                 pr_vdebug("hid descriptor\n");
1978                 if (length != sizeof(struct hid_descriptor))
1979                         goto inv_length;
1980                 break;
1981
1982         case USB_DT_OTG:
1983                 if (length != sizeof(struct usb_otg_descriptor))
1984                         goto inv_length;
1985                 break;
1986
1987         case USB_DT_INTERFACE_ASSOCIATION: {
1988                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1989                 pr_vdebug("interface association descriptor\n");
1990                 if (length != sizeof *ds)
1991                         goto inv_length;
1992                 if (ds->iFunction)
1993                         __entity(STRING, ds->iFunction);
1994         }
1995                 break;
1996
1997         case USB_DT_SS_ENDPOINT_COMP:
1998                 pr_vdebug("EP SS companion descriptor\n");
1999                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2000                         goto inv_length;
2001                 break;
2002
2003         case USB_DT_OTHER_SPEED_CONFIG:
2004         case USB_DT_INTERFACE_POWER:
2005         case USB_DT_DEBUG:
2006         case USB_DT_SECURITY:
2007         case USB_DT_CS_RADIO_CONTROL:
2008                 /* TODO */
2009                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2010                 return -EINVAL;
2011
2012         default:
2013                 /* We should never be here */
2014                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2015                 return -EINVAL;
2016
2017 inv_length:
2018                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2019                           _ds->bLength, _ds->bDescriptorType);
2020                 return -EINVAL;
2021         }
2022
2023 #undef __entity
2024 #undef __entity_check_DESCRIPTOR
2025 #undef __entity_check_INTERFACE
2026 #undef __entity_check_STRING
2027 #undef __entity_check_ENDPOINT
2028
2029         return length;
2030 }
2031
2032 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2033                                      ffs_entity_callback entity, void *priv)
2034 {
2035         const unsigned _len = len;
2036         unsigned long num = 0;
2037
2038         ENTER();
2039
2040         for (;;) {
2041                 int ret;
2042
2043                 if (num == count)
2044                         data = NULL;
2045
2046                 /* Record "descriptor" entity */
2047                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2048                 if (unlikely(ret < 0)) {
2049                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2050                                  num, ret);
2051                         return ret;
2052                 }
2053
2054                 if (!data)
2055                         return _len - len;
2056
2057                 ret = ffs_do_single_desc(data, len, entity, priv);
2058                 if (unlikely(ret < 0)) {
2059                         pr_debug("%s returns %d\n", __func__, ret);
2060                         return ret;
2061                 }
2062
2063                 len -= ret;
2064                 data += ret;
2065                 ++num;
2066         }
2067 }
2068
2069 static int __ffs_data_do_entity(enum ffs_entity_type type,
2070                                 u8 *valuep, struct usb_descriptor_header *desc,
2071                                 void *priv)
2072 {
2073         struct ffs_desc_helper *helper = priv;
2074         struct usb_endpoint_descriptor *d;
2075
2076         ENTER();
2077
2078         switch (type) {
2079         case FFS_DESCRIPTOR:
2080                 break;
2081
2082         case FFS_INTERFACE:
2083                 /*
2084                  * Interfaces are indexed from zero so if we
2085                  * encountered interface "n" then there are at least
2086                  * "n+1" interfaces.
2087                  */
2088                 if (*valuep >= helper->interfaces_count)
2089                         helper->interfaces_count = *valuep + 1;
2090                 break;
2091
2092         case FFS_STRING:
2093                 /*
2094                  * Strings are indexed from 1 (0 is magic ;) reserved
2095                  * for languages list or some such)
2096                  */
2097                 if (*valuep > helper->ffs->strings_count)
2098                         helper->ffs->strings_count = *valuep;
2099                 break;
2100
2101         case FFS_ENDPOINT:
2102                 d = (void *)desc;
2103                 helper->eps_count++;
2104                 if (helper->eps_count >= 15)
2105                         return -EINVAL;
2106                 /* Check if descriptors for any speed were already parsed */
2107                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2108                         helper->ffs->eps_addrmap[helper->eps_count] =
2109                                 d->bEndpointAddress;
2110                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2111                                 d->bEndpointAddress)
2112                         return -EINVAL;
2113                 break;
2114         }
2115
2116         return 0;
2117 }
2118
2119 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2120                                    struct usb_os_desc_header *desc)
2121 {
2122         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2123         u16 w_index = le16_to_cpu(desc->wIndex);
2124
2125         if (bcd_version != 1) {
2126                 pr_vdebug("unsupported os descriptors version: %d",
2127                           bcd_version);
2128                 return -EINVAL;
2129         }
2130         switch (w_index) {
2131         case 0x4:
2132                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2133                 break;
2134         case 0x5:
2135                 *next_type = FFS_OS_DESC_EXT_PROP;
2136                 break;
2137         default:
2138                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2139                 return -EINVAL;
2140         }
2141
2142         return sizeof(*desc);
2143 }
2144
2145 /*
2146  * Process all extended compatibility/extended property descriptors
2147  * of a feature descriptor
2148  */
2149 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2150                                               enum ffs_os_desc_type type,
2151                                               u16 feature_count,
2152                                               ffs_os_desc_callback entity,
2153                                               void *priv,
2154                                               struct usb_os_desc_header *h)
2155 {
2156         int ret;
2157         const unsigned _len = len;
2158
2159         ENTER();
2160
2161         /* loop over all ext compat/ext prop descriptors */
2162         while (feature_count--) {
2163                 ret = entity(type, h, data, len, priv);
2164                 if (unlikely(ret < 0)) {
2165                         pr_debug("bad OS descriptor, type: %d\n", type);
2166                         return ret;
2167                 }
2168                 data += ret;
2169                 len -= ret;
2170         }
2171         return _len - len;
2172 }
2173
2174 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2175 static int __must_check ffs_do_os_descs(unsigned count,
2176                                         char *data, unsigned len,
2177                                         ffs_os_desc_callback entity, void *priv)
2178 {
2179         const unsigned _len = len;
2180         unsigned long num = 0;
2181
2182         ENTER();
2183
2184         for (num = 0; num < count; ++num) {
2185                 int ret;
2186                 enum ffs_os_desc_type type;
2187                 u16 feature_count;
2188                 struct usb_os_desc_header *desc = (void *)data;
2189
2190                 if (len < sizeof(*desc))
2191                         return -EINVAL;
2192
2193                 /*
2194                  * Record "descriptor" entity.
2195                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2196                  * Move the data pointer to the beginning of extended
2197                  * compatibilities proper or extended properties proper
2198                  * portions of the data
2199                  */
2200                 if (le32_to_cpu(desc->dwLength) > len)
2201                         return -EINVAL;
2202
2203                 ret = __ffs_do_os_desc_header(&type, desc);
2204                 if (unlikely(ret < 0)) {
2205                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2206                                  num, ret);
2207                         return ret;
2208                 }
2209                 /*
2210                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2211                  */
2212                 feature_count = le16_to_cpu(desc->wCount);
2213                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2214                     (feature_count > 255 || desc->Reserved))
2215                                 return -EINVAL;
2216                 len -= ret;
2217                 data += ret;
2218
2219                 /*
2220                  * Process all function/property descriptors
2221                  * of this Feature Descriptor
2222                  */
2223                 ret = ffs_do_single_os_desc(data, len, type,
2224                                             feature_count, entity, priv, desc);
2225                 if (unlikely(ret < 0)) {
2226                         pr_debug("%s returns %d\n", __func__, ret);
2227                         return ret;
2228                 }
2229
2230                 len -= ret;
2231                 data += ret;
2232         }
2233         return _len - len;
2234 }
2235
2236 /**
2237  * Validate contents of the buffer from userspace related to OS descriptors.
2238  */
2239 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2240                                  struct usb_os_desc_header *h, void *data,
2241                                  unsigned len, void *priv)
2242 {
2243         struct ffs_data *ffs = priv;
2244         u8 length;
2245
2246         ENTER();
2247
2248         switch (type) {
2249         case FFS_OS_DESC_EXT_COMPAT: {
2250                 struct usb_ext_compat_desc *d = data;
2251                 int i;
2252
2253                 if (len < sizeof(*d) ||
2254                     d->bFirstInterfaceNumber >= ffs->interfaces_count ||
2255                     !d->Reserved1)
2256                         return -EINVAL;
2257                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2258                         if (d->Reserved2[i])
2259                                 return -EINVAL;
2260
2261                 length = sizeof(struct usb_ext_compat_desc);
2262         }
2263                 break;
2264         case FFS_OS_DESC_EXT_PROP: {
2265                 struct usb_ext_prop_desc *d = data;
2266                 u32 type, pdl;
2267                 u16 pnl;
2268
2269                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2270                         return -EINVAL;
2271                 length = le32_to_cpu(d->dwSize);
2272                 type = le32_to_cpu(d->dwPropertyDataType);
2273                 if (type < USB_EXT_PROP_UNICODE ||
2274                     type > USB_EXT_PROP_UNICODE_MULTI) {
2275                         pr_vdebug("unsupported os descriptor property type: %d",
2276                                   type);
2277                         return -EINVAL;
2278                 }
2279                 pnl = le16_to_cpu(d->wPropertyNameLength);
2280                 pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
2281                 if (length != 14 + pnl + pdl) {
2282                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2283                                   length, pnl, pdl, type);
2284                         return -EINVAL;
2285                 }
2286                 ++ffs->ms_os_descs_ext_prop_count;
2287                 /* property name reported to the host as "WCHAR"s */
2288                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2289                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2290         }
2291                 break;
2292         default:
2293                 pr_vdebug("unknown descriptor: %d\n", type);
2294                 return -EINVAL;
2295         }
2296         return length;
2297 }
2298
2299 static int __ffs_data_got_descs(struct ffs_data *ffs,
2300                                 char *const _data, size_t len)
2301 {
2302         char *data = _data, *raw_descs;
2303         unsigned os_descs_count = 0, counts[3], flags;
2304         int ret = -EINVAL, i;
2305         struct ffs_desc_helper helper;
2306
2307         ENTER();
2308
2309         if (get_unaligned_le32(data + 4) != len)
2310                 goto error;
2311
2312         switch (get_unaligned_le32(data)) {
2313         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2314                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2315                 data += 8;
2316                 len  -= 8;
2317                 break;
2318         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2319                 flags = get_unaligned_le32(data + 8);
2320                 ffs->user_flags = flags;
2321                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2322                               FUNCTIONFS_HAS_HS_DESC |
2323                               FUNCTIONFS_HAS_SS_DESC |
2324                               FUNCTIONFS_HAS_MS_OS_DESC |
2325                               FUNCTIONFS_VIRTUAL_ADDR |
2326                               FUNCTIONFS_EVENTFD |
2327                               FUNCTIONFS_ALL_CTRL_RECIP |
2328                               FUNCTIONFS_CONFIG0_SETUP)) {
2329                         ret = -ENOSYS;
2330                         goto error;
2331                 }
2332                 data += 12;
2333                 len  -= 12;
2334                 break;
2335         default:
2336                 goto error;
2337         }
2338
2339         if (flags & FUNCTIONFS_EVENTFD) {
2340                 if (len < 4)
2341                         goto error;
2342                 ffs->ffs_eventfd =
2343                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2344                 if (IS_ERR(ffs->ffs_eventfd)) {
2345                         ret = PTR_ERR(ffs->ffs_eventfd);
2346                         ffs->ffs_eventfd = NULL;
2347                         goto error;
2348                 }
2349                 data += 4;
2350                 len  -= 4;
2351         }
2352
2353         /* Read fs_count, hs_count and ss_count (if present) */
2354         for (i = 0; i < 3; ++i) {
2355                 if (!(flags & (1 << i))) {
2356                         counts[i] = 0;
2357                 } else if (len < 4) {
2358                         goto error;
2359                 } else {
2360                         counts[i] = get_unaligned_le32(data);
2361                         data += 4;
2362                         len  -= 4;
2363                 }
2364         }
2365         if (flags & (1 << i)) {
2366                 os_descs_count = get_unaligned_le32(data);
2367                 data += 4;
2368                 len -= 4;
2369         };
2370
2371         /* Read descriptors */
2372         raw_descs = data;
2373         helper.ffs = ffs;
2374         for (i = 0; i < 3; ++i) {
2375                 if (!counts[i])
2376                         continue;
2377                 helper.interfaces_count = 0;
2378                 helper.eps_count = 0;
2379                 ret = ffs_do_descs(counts[i], data, len,
2380                                    __ffs_data_do_entity, &helper);
2381                 if (ret < 0)
2382                         goto error;
2383                 if (!ffs->eps_count && !ffs->interfaces_count) {
2384                         ffs->eps_count = helper.eps_count;
2385                         ffs->interfaces_count = helper.interfaces_count;
2386                 } else {
2387                         if (ffs->eps_count != helper.eps_count) {
2388                                 ret = -EINVAL;
2389                                 goto error;
2390                         }
2391                         if (ffs->interfaces_count != helper.interfaces_count) {
2392                                 ret = -EINVAL;
2393                                 goto error;
2394                         }
2395                 }
2396                 data += ret;
2397                 len  -= ret;
2398         }
2399         if (os_descs_count) {
2400                 ret = ffs_do_os_descs(os_descs_count, data, len,
2401                                       __ffs_data_do_os_desc, ffs);
2402                 if (ret < 0)
2403                         goto error;
2404                 data += ret;
2405                 len -= ret;
2406         }
2407
2408         if (raw_descs == data || len) {
2409                 ret = -EINVAL;
2410                 goto error;
2411         }
2412
2413         ffs->raw_descs_data     = _data;
2414         ffs->raw_descs          = raw_descs;
2415         ffs->raw_descs_length   = data - raw_descs;
2416         ffs->fs_descs_count     = counts[0];
2417         ffs->hs_descs_count     = counts[1];
2418         ffs->ss_descs_count     = counts[2];
2419         ffs->ms_os_descs_count  = os_descs_count;
2420
2421         return 0;
2422
2423 error:
2424         kfree(_data);
2425         return ret;
2426 }
2427
2428 static int __ffs_data_got_strings(struct ffs_data *ffs,
2429                                   char *const _data, size_t len)
2430 {
2431         u32 str_count, needed_count, lang_count;
2432         struct usb_gadget_strings **stringtabs, *t;
2433         const char *data = _data;
2434         struct usb_string *s;
2435
2436         ENTER();
2437
2438         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2439                      get_unaligned_le32(data + 4) != len))
2440                 goto error;
2441         str_count  = get_unaligned_le32(data + 8);
2442         lang_count = get_unaligned_le32(data + 12);
2443
2444         /* if one is zero the other must be zero */
2445         if (unlikely(!str_count != !lang_count))
2446                 goto error;
2447
2448         /* Do we have at least as many strings as descriptors need? */
2449         needed_count = ffs->strings_count;
2450         if (unlikely(str_count < needed_count))
2451                 goto error;
2452
2453         /*
2454          * If we don't need any strings just return and free all
2455          * memory.
2456          */
2457         if (!needed_count) {
2458                 kfree(_data);
2459                 return 0;
2460         }
2461
2462         /* Allocate everything in one chunk so there's less maintenance. */
2463         {
2464                 unsigned i = 0;
2465                 vla_group(d);
2466                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2467                         lang_count + 1);
2468                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2469                 vla_item(d, struct usb_string, strings,
2470                         lang_count*(needed_count+1));
2471
2472                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2473
2474                 if (unlikely(!vlabuf)) {
2475                         kfree(_data);
2476                         return -ENOMEM;
2477                 }
2478
2479                 /* Initialize the VLA pointers */
2480                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2481                 t = vla_ptr(vlabuf, d, stringtab);
2482                 i = lang_count;
2483                 do {
2484                         *stringtabs++ = t++;
2485                 } while (--i);
2486                 *stringtabs = NULL;
2487
2488                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2489                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2490                 t = vla_ptr(vlabuf, d, stringtab);
2491                 s = vla_ptr(vlabuf, d, strings);
2492         }
2493
2494         /* For each language */
2495         data += 16;
2496         len -= 16;
2497
2498         do { /* lang_count > 0 so we can use do-while */
2499                 unsigned needed = needed_count;
2500
2501                 if (unlikely(len < 3))
2502                         goto error_free;
2503                 t->language = get_unaligned_le16(data);
2504                 t->strings  = s;
2505                 ++t;
2506
2507                 data += 2;
2508                 len -= 2;
2509
2510                 /* For each string */
2511                 do { /* str_count > 0 so we can use do-while */
2512                         size_t length = strnlen(data, len);
2513
2514                         if (unlikely(length == len))
2515                                 goto error_free;
2516
2517                         /*
2518                          * User may provide more strings then we need,
2519                          * if that's the case we simply ignore the
2520                          * rest
2521                          */
2522                         if (likely(needed)) {
2523                                 /*
2524                                  * s->id will be set while adding
2525                                  * function to configuration so for
2526                                  * now just leave garbage here.
2527                                  */
2528                                 s->s = data;
2529                                 --needed;
2530                                 ++s;
2531                         }
2532
2533                         data += length + 1;
2534                         len -= length + 1;
2535                 } while (--str_count);
2536
2537                 s->id = 0;   /* terminator */
2538                 s->s = NULL;
2539                 ++s;
2540
2541         } while (--lang_count);
2542
2543         /* Some garbage left? */
2544         if (unlikely(len))
2545                 goto error_free;
2546
2547         /* Done! */
2548         ffs->stringtabs = stringtabs;
2549         ffs->raw_strings = _data;
2550
2551         return 0;
2552
2553 error_free:
2554         kfree(stringtabs);
2555 error:
2556         kfree(_data);
2557         return -EINVAL;
2558 }
2559
2560
2561 /* Events handling and management *******************************************/
2562
2563 static void __ffs_event_add(struct ffs_data *ffs,
2564                             enum usb_functionfs_event_type type)
2565 {
2566         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2567         int neg = 0;
2568
2569         /*
2570          * Abort any unhandled setup
2571          *
2572          * We do not need to worry about some cmpxchg() changing value
2573          * of ffs->setup_state without holding the lock because when
2574          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2575          * the source does nothing.
2576          */
2577         if (ffs->setup_state == FFS_SETUP_PENDING)
2578                 ffs->setup_state = FFS_SETUP_CANCELLED;
2579
2580         /*
2581          * Logic of this function guarantees that there are at most four pending
2582          * evens on ffs->ev.types queue.  This is important because the queue
2583          * has space for four elements only and __ffs_ep0_read_events function
2584          * depends on that limit as well.  If more event types are added, those
2585          * limits have to be revisited or guaranteed to still hold.
2586          */
2587         switch (type) {
2588         case FUNCTIONFS_RESUME:
2589                 rem_type2 = FUNCTIONFS_SUSPEND;
2590                 /* FALL THROUGH */
2591         case FUNCTIONFS_SUSPEND:
2592         case FUNCTIONFS_SETUP:
2593                 rem_type1 = type;
2594                 /* Discard all similar events */
2595                 break;
2596
2597         case FUNCTIONFS_BIND:
2598         case FUNCTIONFS_UNBIND:
2599         case FUNCTIONFS_DISABLE:
2600         case FUNCTIONFS_ENABLE:
2601                 /* Discard everything other then power management. */
2602                 rem_type1 = FUNCTIONFS_SUSPEND;
2603                 rem_type2 = FUNCTIONFS_RESUME;
2604                 neg = 1;
2605                 break;
2606
2607         default:
2608                 WARN(1, "%d: unknown event, this should not happen\n", type);
2609                 return;
2610         }
2611
2612         {
2613                 u8 *ev  = ffs->ev.types, *out = ev;
2614                 unsigned n = ffs->ev.count;
2615                 for (; n; --n, ++ev)
2616                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2617                                 *out++ = *ev;
2618                         else
2619                                 pr_vdebug("purging event %d\n", *ev);
2620                 ffs->ev.count = out - ffs->ev.types;
2621         }
2622
2623         pr_vdebug("adding event %d\n", type);
2624         ffs->ev.types[ffs->ev.count++] = type;
2625         wake_up_locked(&ffs->ev.waitq);
2626         if (ffs->ffs_eventfd)
2627                 eventfd_signal(ffs->ffs_eventfd, 1);
2628 }
2629
2630 static void ffs_event_add(struct ffs_data *ffs,
2631                           enum usb_functionfs_event_type type)
2632 {
2633         unsigned long flags;
2634         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2635         __ffs_event_add(ffs, type);
2636         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2637 }
2638
2639 /* Bind/unbind USB function hooks *******************************************/
2640
2641 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2642 {
2643         int i;
2644
2645         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2646                 if (ffs->eps_addrmap[i] == endpoint_address)
2647                         return i;
2648         return -ENOENT;
2649 }
2650
2651 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2652                                     struct usb_descriptor_header *desc,
2653                                     void *priv)
2654 {
2655         struct usb_endpoint_descriptor *ds = (void *)desc;
2656         struct ffs_function *func = priv;
2657         struct ffs_ep *ffs_ep;
2658         unsigned ep_desc_id;
2659         int idx;
2660         static const char *speed_names[] = { "full", "high", "super" };
2661
2662         if (type != FFS_DESCRIPTOR)
2663                 return 0;
2664
2665         /*
2666          * If ss_descriptors is not NULL, we are reading super speed
2667          * descriptors; if hs_descriptors is not NULL, we are reading high
2668          * speed descriptors; otherwise, we are reading full speed
2669          * descriptors.
2670          */
2671         if (func->function.ss_descriptors) {
2672                 ep_desc_id = 2;
2673                 func->function.ss_descriptors[(long)valuep] = desc;
2674         } else if (func->function.hs_descriptors) {
2675                 ep_desc_id = 1;
2676                 func->function.hs_descriptors[(long)valuep] = desc;
2677         } else {
2678                 ep_desc_id = 0;
2679                 func->function.fs_descriptors[(long)valuep]    = desc;
2680         }
2681
2682         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2683                 return 0;
2684
2685         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2686         if (idx < 0)
2687                 return idx;
2688
2689         ffs_ep = func->eps + idx;
2690
2691         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2692                 pr_err("two %sspeed descriptors for EP %d\n",
2693                           speed_names[ep_desc_id],
2694                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2695                 return -EINVAL;
2696         }
2697         ffs_ep->descs[ep_desc_id] = ds;
2698
2699         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2700         if (ffs_ep->ep) {
2701                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2702                 if (!ds->wMaxPacketSize)
2703                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2704         } else {
2705                 struct usb_request *req;
2706                 struct usb_ep *ep;
2707                 u8 bEndpointAddress;
2708
2709                 /*
2710                  * We back up bEndpointAddress because autoconfig overwrites
2711                  * it with physical endpoint address.
2712                  */
2713                 bEndpointAddress = ds->bEndpointAddress;
2714                 pr_vdebug("autoconfig\n");
2715                 ep = usb_ep_autoconfig(func->gadget, ds);
2716                 if (unlikely(!ep))
2717                         return -ENOTSUPP;
2718                 ep->driver_data = func->eps + idx;
2719
2720                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2721                 if (unlikely(!req))
2722                         return -ENOMEM;
2723
2724                 ffs_ep->ep  = ep;
2725                 ffs_ep->req = req;
2726                 func->eps_revmap[ds->bEndpointAddress &
2727                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2728                 /*
2729                  * If we use virtual address mapping, we restore
2730                  * original bEndpointAddress value.
2731                  */
2732                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2733                         ds->bEndpointAddress = bEndpointAddress;
2734         }
2735         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2736
2737         return 0;
2738 }
2739
2740 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2741                                    struct usb_descriptor_header *desc,
2742                                    void *priv)
2743 {
2744         struct ffs_function *func = priv;
2745         unsigned idx;
2746         u8 newValue;
2747
2748         switch (type) {
2749         default:
2750         case FFS_DESCRIPTOR:
2751                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2752                 return 0;
2753
2754         case FFS_INTERFACE:
2755                 idx = *valuep;
2756                 if (func->interfaces_nums[idx] < 0) {
2757                         int id = usb_interface_id(func->conf, &func->function);
2758                         if (unlikely(id < 0))
2759                                 return id;
2760                         func->interfaces_nums[idx] = id;
2761                 }
2762                 newValue = func->interfaces_nums[idx];
2763                 break;
2764
2765         case FFS_STRING:
2766                 /* String' IDs are allocated when fsf_data is bound to cdev */
2767                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2768                 break;
2769
2770         case FFS_ENDPOINT:
2771                 /*
2772                  * USB_DT_ENDPOINT are handled in
2773                  * __ffs_func_bind_do_descs().
2774                  */
2775                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2776                         return 0;
2777
2778                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2779                 if (unlikely(!func->eps[idx].ep))
2780                         return -EINVAL;
2781
2782                 {
2783                         struct usb_endpoint_descriptor **descs;
2784                         descs = func->eps[idx].descs;
2785                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2786                 }
2787                 break;
2788         }
2789
2790         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2791         *valuep = newValue;
2792         return 0;
2793 }
2794
2795 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2796                                       struct usb_os_desc_header *h, void *data,
2797                                       unsigned len, void *priv)
2798 {
2799         struct ffs_function *func = priv;
2800         u8 length = 0;
2801
2802         switch (type) {
2803         case FFS_OS_DESC_EXT_COMPAT: {
2804                 struct usb_ext_compat_desc *desc = data;
2805                 struct usb_os_desc_table *t;
2806
2807                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2808                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2809                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2810                        ARRAY_SIZE(desc->CompatibleID) +
2811                        ARRAY_SIZE(desc->SubCompatibleID));
2812                 length = sizeof(*desc);
2813         }
2814                 break;
2815         case FFS_OS_DESC_EXT_PROP: {
2816                 struct usb_ext_prop_desc *desc = data;
2817                 struct usb_os_desc_table *t;
2818                 struct usb_os_desc_ext_prop *ext_prop;
2819                 char *ext_prop_name;
2820                 char *ext_prop_data;
2821
2822                 t = &func->function.os_desc_table[h->interface];
2823                 t->if_id = func->interfaces_nums[h->interface];
2824
2825                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2826                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2827
2828                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2829                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2830                 ext_prop->data_len = le32_to_cpu(*(u32 *)
2831                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2832                 length = ext_prop->name_len + ext_prop->data_len + 14;
2833
2834                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2835                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2836                         ext_prop->name_len;
2837
2838                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2839                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2840                         ext_prop->data_len;
2841                 memcpy(ext_prop_data,
2842                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2843                        ext_prop->data_len);
2844                 /* unicode data reported to the host as "WCHAR"s */
2845                 switch (ext_prop->type) {
2846                 case USB_EXT_PROP_UNICODE:
2847                 case USB_EXT_PROP_UNICODE_ENV:
2848                 case USB_EXT_PROP_UNICODE_LINK:
2849                 case USB_EXT_PROP_UNICODE_MULTI:
2850                         ext_prop->data_len *= 2;
2851                         break;
2852                 }
2853                 ext_prop->data = ext_prop_data;
2854
2855                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2856                        ext_prop->name_len);
2857                 /* property name reported to the host as "WCHAR"s */
2858                 ext_prop->name_len *= 2;
2859                 ext_prop->name = ext_prop_name;
2860
2861                 t->os_desc->ext_prop_len +=
2862                         ext_prop->name_len + ext_prop->data_len + 14;
2863                 ++t->os_desc->ext_prop_count;
2864                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2865         }
2866                 break;
2867         default:
2868                 pr_vdebug("unknown descriptor: %d\n", type);
2869         }
2870
2871         return length;
2872 }
2873
2874 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2875                                                 struct usb_configuration *c)
2876 {
2877         struct ffs_function *func = ffs_func_from_usb(f);
2878         struct f_fs_opts *ffs_opts =
2879                 container_of(f->fi, struct f_fs_opts, func_inst);
2880         int ret;
2881
2882         ENTER();
2883
2884         /*
2885          * Legacy gadget triggers binding in functionfs_ready_callback,
2886          * which already uses locking; taking the same lock here would
2887          * cause a deadlock.
2888          *
2889          * Configfs-enabled gadgets however do need ffs_dev_lock.
2890          */
2891         if (!ffs_opts->no_configfs)
2892                 ffs_dev_lock();
2893         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2894         func->ffs = ffs_opts->dev->ffs_data;
2895         if (!ffs_opts->no_configfs)
2896                 ffs_dev_unlock();
2897         if (ret)
2898                 return ERR_PTR(ret);
2899
2900         func->conf = c;
2901         func->gadget = c->cdev->gadget;
2902
2903         /*
2904          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2905          * configurations are bound in sequence with list_for_each_entry,
2906          * in each configuration its functions are bound in sequence
2907          * with list_for_each_entry, so we assume no race condition
2908          * with regard to ffs_opts->bound access
2909          */
2910         if (!ffs_opts->refcnt) {
2911                 ret = functionfs_bind(func->ffs, c->cdev);
2912                 if (ret)
2913                         return ERR_PTR(ret);
2914         }
2915         ffs_opts->refcnt++;
2916         func->function.strings = func->ffs->stringtabs;
2917
2918         return ffs_opts;
2919 }
2920
2921 static int _ffs_func_bind(struct usb_configuration *c,
2922                           struct usb_function *f)
2923 {
2924         struct ffs_function *func = ffs_func_from_usb(f);
2925         struct ffs_data *ffs = func->ffs;
2926
2927         const int full = !!func->ffs->fs_descs_count;
2928         const int high = gadget_is_dualspeed(func->gadget) &&
2929                 func->ffs->hs_descs_count;
2930         const int super = gadget_is_superspeed(func->gadget) &&
2931                 func->ffs->ss_descs_count;
2932
2933         int fs_len, hs_len, ss_len, ret, i;
2934         struct ffs_ep *eps_ptr;
2935
2936         /* Make it a single chunk, less management later on */
2937         vla_group(d);
2938         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2939         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2940                 full ? ffs->fs_descs_count + 1 : 0);
2941         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2942                 high ? ffs->hs_descs_count + 1 : 0);
2943         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2944                 super ? ffs->ss_descs_count + 1 : 0);
2945         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2946         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2947                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2948         vla_item_with_sz(d, char[16], ext_compat,
2949                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2950         vla_item_with_sz(d, struct usb_os_desc, os_desc,
2951                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2952         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
2953                          ffs->ms_os_descs_ext_prop_count);
2954         vla_item_with_sz(d, char, ext_prop_name,
2955                          ffs->ms_os_descs_ext_prop_name_len);
2956         vla_item_with_sz(d, char, ext_prop_data,
2957                          ffs->ms_os_descs_ext_prop_data_len);
2958         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2959         char *vlabuf;
2960
2961         ENTER();
2962
2963         /* Has descriptors only for speeds gadget does not support */
2964         if (unlikely(!(full | high | super)))
2965                 return -ENOTSUPP;
2966
2967         /* Allocate a single chunk, less management later on */
2968         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
2969         if (unlikely(!vlabuf))
2970                 return -ENOMEM;
2971
2972         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
2973         ffs->ms_os_descs_ext_prop_name_avail =
2974                 vla_ptr(vlabuf, d, ext_prop_name);
2975         ffs->ms_os_descs_ext_prop_data_avail =
2976                 vla_ptr(vlabuf, d, ext_prop_data);
2977
2978         /* Copy descriptors  */
2979         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
2980                ffs->raw_descs_length);
2981
2982         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2983         eps_ptr = vla_ptr(vlabuf, d, eps);
2984         for (i = 0; i < ffs->eps_count; i++)
2985                 eps_ptr[i].num = -1;
2986
2987         /* Save pointers
2988          * d_eps == vlabuf, func->eps used to kfree vlabuf later
2989         */
2990         func->eps             = vla_ptr(vlabuf, d, eps);
2991         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
2992
2993         /*
2994          * Go through all the endpoint descriptors and allocate
2995          * endpoints first, so that later we can rewrite the endpoint
2996          * numbers without worrying that it may be described later on.
2997          */
2998         if (likely(full)) {
2999                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3000                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3001                                       vla_ptr(vlabuf, d, raw_descs),
3002                                       d_raw_descs__sz,
3003                                       __ffs_func_bind_do_descs, func);
3004                 if (unlikely(fs_len < 0)) {
3005                         ret = fs_len;
3006                         goto error;
3007                 }
3008         } else {
3009                 fs_len = 0;
3010         }
3011
3012         if (likely(high)) {
3013                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3014                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3015                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3016                                       d_raw_descs__sz - fs_len,
3017                                       __ffs_func_bind_do_descs, func);
3018                 if (unlikely(hs_len < 0)) {
3019                         ret = hs_len;
3020                         goto error;
3021                 }
3022         } else {
3023                 hs_len = 0;
3024         }
3025
3026         if (likely(super)) {
3027                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3028                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3029                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3030                                 d_raw_descs__sz - fs_len - hs_len,
3031                                 __ffs_func_bind_do_descs, func);
3032                 if (unlikely(ss_len < 0)) {
3033                         ret = ss_len;
3034                         goto error;
3035                 }
3036         } else {
3037                 ss_len = 0;
3038         }
3039
3040         /*
3041          * Now handle interface numbers allocation and interface and
3042          * endpoint numbers rewriting.  We can do that in one go
3043          * now.
3044          */
3045         ret = ffs_do_descs(ffs->fs_descs_count +
3046                            (high ? ffs->hs_descs_count : 0) +
3047                            (super ? ffs->ss_descs_count : 0),
3048                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3049                            __ffs_func_bind_do_nums, func);
3050         if (unlikely(ret < 0))
3051                 goto error;
3052
3053         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3054         if (c->cdev->use_os_string) {
3055                 for (i = 0; i < ffs->interfaces_count; ++i) {
3056                         struct usb_os_desc *desc;
3057
3058                         desc = func->function.os_desc_table[i].os_desc =
3059                                 vla_ptr(vlabuf, d, os_desc) +
3060                                 i * sizeof(struct usb_os_desc);
3061                         desc->ext_compat_id =
3062                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3063                         INIT_LIST_HEAD(&desc->ext_prop);
3064                 }
3065                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3066                                       vla_ptr(vlabuf, d, raw_descs) +
3067                                       fs_len + hs_len + ss_len,
3068                                       d_raw_descs__sz - fs_len - hs_len -
3069                                       ss_len,
3070                                       __ffs_func_bind_do_os_desc, func);
3071                 if (unlikely(ret < 0))
3072                         goto error;
3073         }
3074         func->function.os_desc_n =
3075                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3076
3077         /* And we're done */
3078         ffs_event_add(ffs, FUNCTIONFS_BIND);
3079         return 0;
3080
3081 error:
3082         /* XXX Do we need to release all claimed endpoints here? */
3083         return ret;
3084 }
3085
3086 static int ffs_func_bind(struct usb_configuration *c,
3087                          struct usb_function *f)
3088 {
3089         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3090         struct ffs_function *func = ffs_func_from_usb(f);
3091         int ret;
3092
3093         if (IS_ERR(ffs_opts))
3094                 return PTR_ERR(ffs_opts);
3095
3096         ret = _ffs_func_bind(c, f);
3097         if (ret && !--ffs_opts->refcnt)
3098                 functionfs_unbind(func->ffs);
3099
3100         return ret;
3101 }
3102
3103
3104 /* Other USB function hooks *************************************************/
3105
3106 static void ffs_reset_work(struct work_struct *work)
3107 {
3108         struct ffs_data *ffs = container_of(work,
3109                 struct ffs_data, reset_work);
3110         ffs_data_reset(ffs);
3111 }
3112
3113 static int ffs_func_set_alt(struct usb_function *f,
3114                             unsigned interface, unsigned alt)
3115 {
3116         struct ffs_function *func = ffs_func_from_usb(f);
3117         struct ffs_data *ffs = func->ffs;
3118         int ret = 0, intf;
3119
3120         if (alt != (unsigned)-1) {
3121                 intf = ffs_func_revmap_intf(func, interface);
3122                 if (unlikely(intf < 0))
3123                         return intf;
3124         }
3125
3126         if (ffs->func)
3127                 ffs_func_eps_disable(ffs->func);
3128
3129         if (ffs->state == FFS_DEACTIVATED) {
3130                 ffs->state = FFS_CLOSING;
3131                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3132                 schedule_work(&ffs->reset_work);
3133                 return -ENODEV;
3134         }
3135
3136         if (ffs->state != FFS_ACTIVE)
3137                 return -ENODEV;
3138
3139         if (alt == (unsigned)-1) {
3140                 ffs->func = NULL;
3141                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3142                 return 0;
3143         }
3144
3145         ffs->func = func;
3146         ret = ffs_func_eps_enable(func);
3147         if (likely(ret >= 0))
3148                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3149         return ret;
3150 }
3151
3152 static void ffs_func_disable(struct usb_function *f)
3153 {
3154         ffs_func_set_alt(f, 0, (unsigned)-1);
3155 }
3156
3157 static int ffs_func_setup(struct usb_function *f,
3158                           const struct usb_ctrlrequest *creq)
3159 {
3160         struct ffs_function *func = ffs_func_from_usb(f);
3161         struct ffs_data *ffs = func->ffs;
3162         unsigned long flags;
3163         int ret;
3164
3165         ENTER();
3166
3167         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3168         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3169         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3170         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3171         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3172
3173         /*
3174          * Most requests directed to interface go through here
3175          * (notable exceptions are set/get interface) so we need to
3176          * handle them.  All other either handled by composite or
3177          * passed to usb_configuration->setup() (if one is set).  No
3178          * matter, we will handle requests directed to endpoint here
3179          * as well (as it's straightforward).  Other request recipient
3180          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3181          * is being used.
3182          */
3183         if (ffs->state != FFS_ACTIVE)
3184                 return -ENODEV;
3185
3186         switch (creq->bRequestType & USB_RECIP_MASK) {
3187         case USB_RECIP_INTERFACE:
3188                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3189                 if (unlikely(ret < 0))
3190                         return ret;
3191                 break;
3192
3193         case USB_RECIP_ENDPOINT:
3194                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3195                 if (unlikely(ret < 0))
3196                         return ret;
3197                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3198                         ret = func->ffs->eps_addrmap[ret];
3199                 break;
3200
3201         default:
3202                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3203                         ret = le16_to_cpu(creq->wIndex);
3204                 else
3205                         return -EOPNOTSUPP;
3206         }
3207
3208         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3209         ffs->ev.setup = *creq;
3210         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3211         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3212         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3213
3214         return 0;
3215 }
3216
3217 static bool ffs_func_req_match(struct usb_function *f,
3218                                const struct usb_ctrlrequest *creq,
3219                                bool config0)
3220 {
3221         struct ffs_function *func = ffs_func_from_usb(f);
3222
3223         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3224                 return false;
3225
3226         switch (creq->bRequestType & USB_RECIP_MASK) {
3227         case USB_RECIP_INTERFACE:
3228                 return ffs_func_revmap_intf(func,
3229                                             le16_to_cpu(creq->wIndex) >= 0);
3230         case USB_RECIP_ENDPOINT:
3231                 return ffs_func_revmap_ep(func,
3232                                           le16_to_cpu(creq->wIndex) >= 0);
3233         default:
3234                 return (bool) (func->ffs->user_flags &
3235                                FUNCTIONFS_ALL_CTRL_RECIP);
3236         }
3237 }
3238
3239 static void ffs_func_suspend(struct usb_function *f)
3240 {
3241         ENTER();
3242         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3243 }
3244
3245 static void ffs_func_resume(struct usb_function *f)
3246 {
3247         ENTER();
3248         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3249 }
3250
3251
3252 /* Endpoint and interface numbers reverse mapping ***************************/
3253
3254 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3255 {
3256         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3257         return num ? num : -EDOM;
3258 }
3259
3260 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3261 {
3262         short *nums = func->interfaces_nums;
3263         unsigned count = func->ffs->interfaces_count;
3264
3265         for (; count; --count, ++nums) {
3266                 if (*nums >= 0 && *nums == intf)
3267                         return nums - func->interfaces_nums;
3268         }
3269
3270         return -EDOM;
3271 }
3272
3273
3274 /* Devices management *******************************************************/
3275
3276 static LIST_HEAD(ffs_devices);
3277
3278 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3279 {
3280         struct ffs_dev *dev;
3281
3282         list_for_each_entry(dev, &ffs_devices, entry) {
3283                 if (!dev->name || !name)
3284                         continue;
3285                 if (strcmp(dev->name, name) == 0)
3286                         return dev;
3287         }
3288
3289         return NULL;
3290 }
3291
3292 /*
3293  * ffs_lock must be taken by the caller of this function
3294  */
3295 static struct ffs_dev *_ffs_get_single_dev(void)
3296 {
3297         struct ffs_dev *dev;
3298
3299         if (list_is_singular(&ffs_devices)) {
3300                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3301                 if (dev->single)
3302                         return dev;
3303         }
3304
3305         return NULL;
3306 }
3307
3308 /*
3309  * ffs_lock must be taken by the caller of this function
3310  */
3311 static struct ffs_dev *_ffs_find_dev(const char *name)
3312 {
3313         struct ffs_dev *dev;
3314
3315         dev = _ffs_get_single_dev();
3316         if (dev)
3317                 return dev;
3318
3319         return _ffs_do_find_dev(name);
3320 }
3321
3322 /* Configfs support *********************************************************/
3323
3324 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3325 {
3326         return container_of(to_config_group(item), struct f_fs_opts,
3327                             func_inst.group);
3328 }
3329
3330 static void ffs_attr_release(struct config_item *item)
3331 {
3332         struct f_fs_opts *opts = to_ffs_opts(item);
3333
3334         usb_put_function_instance(&opts->func_inst);
3335 }
3336
3337 static struct configfs_item_operations ffs_item_ops = {
3338         .release        = ffs_attr_release,
3339 };
3340
3341 static struct config_item_type ffs_func_type = {
3342         .ct_item_ops    = &ffs_item_ops,
3343         .ct_owner       = THIS_MODULE,
3344 };
3345
3346
3347 /* Function registration interface ******************************************/
3348
3349 static void ffs_free_inst(struct usb_function_instance *f)
3350 {
3351         struct f_fs_opts *opts;
3352
3353         opts = to_f_fs_opts(f);
3354         ffs_dev_lock();
3355         _ffs_free_dev(opts->dev);
3356         ffs_dev_unlock();
3357         kfree(opts);
3358 }
3359
3360 #define MAX_INST_NAME_LEN       40
3361
3362 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3363 {
3364         struct f_fs_opts *opts;
3365         char *ptr;
3366         const char *tmp;
3367         int name_len, ret;
3368
3369         name_len = strlen(name) + 1;
3370         if (name_len > MAX_INST_NAME_LEN)
3371                 return -ENAMETOOLONG;
3372
3373         ptr = kstrndup(name, name_len, GFP_KERNEL);
3374         if (!ptr)
3375                 return -ENOMEM;
3376
3377         opts = to_f_fs_opts(fi);
3378         tmp = NULL;
3379
3380         ffs_dev_lock();
3381
3382         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
3383         ret = _ffs_name_dev(opts->dev, ptr);
3384         if (ret) {
3385                 kfree(ptr);
3386                 ffs_dev_unlock();
3387                 return ret;
3388         }
3389         opts->dev->name_allocated = true;
3390
3391         ffs_dev_unlock();
3392
3393         kfree(tmp);
3394
3395         return 0;
3396 }
3397
3398 static struct usb_function_instance *ffs_alloc_inst(void)
3399 {
3400         struct f_fs_opts *opts;
3401         struct ffs_dev *dev;
3402
3403         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3404         if (!opts)
3405                 return ERR_PTR(-ENOMEM);
3406
3407         opts->func_inst.set_inst_name = ffs_set_inst_name;
3408         opts->func_inst.free_func_inst = ffs_free_inst;
3409         ffs_dev_lock();
3410         dev = _ffs_alloc_dev();
3411         ffs_dev_unlock();
3412         if (IS_ERR(dev)) {
3413                 kfree(opts);
3414                 return ERR_CAST(dev);
3415         }
3416         opts->dev = dev;
3417         dev->opts = opts;
3418
3419         config_group_init_type_name(&opts->func_inst.group, "",
3420                                     &ffs_func_type);
3421         return &opts->func_inst;
3422 }
3423
3424 static void ffs_free(struct usb_function *f)
3425 {
3426         kfree(ffs_func_from_usb(f));
3427 }
3428
3429 static void ffs_func_unbind(struct usb_configuration *c,
3430                             struct usb_function *f)
3431 {
3432         struct ffs_function *func = ffs_func_from_usb(f);
3433         struct ffs_data *ffs = func->ffs;
3434         struct f_fs_opts *opts =
3435                 container_of(f->fi, struct f_fs_opts, func_inst);
3436         struct ffs_ep *ep = func->eps;
3437         unsigned count = ffs->eps_count;
3438         unsigned long flags;
3439
3440         ENTER();
3441         if (ffs->func == func) {
3442                 ffs_func_eps_disable(func);
3443                 ffs->func = NULL;
3444         }
3445
3446         if (!--opts->refcnt)
3447                 functionfs_unbind(ffs);
3448
3449         /* cleanup after autoconfig */
3450         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3451         do {
3452                 if (ep->ep && ep->req)
3453                         usb_ep_free_request(ep->ep, ep->req);
3454                 ep->req = NULL;
3455                 ++ep;
3456         } while (--count);
3457         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3458         kfree(func->eps);
3459         func->eps = NULL;
3460         /*
3461          * eps, descriptors and interfaces_nums are allocated in the
3462          * same chunk so only one free is required.
3463          */
3464         func->function.fs_descriptors = NULL;
3465         func->function.hs_descriptors = NULL;
3466         func->function.ss_descriptors = NULL;
3467         func->interfaces_nums = NULL;
3468
3469         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3470 }
3471
3472 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3473 {
3474         struct ffs_function *func;
3475
3476         ENTER();
3477
3478         func = kzalloc(sizeof(*func), GFP_KERNEL);
3479         if (unlikely(!func))
3480                 return ERR_PTR(-ENOMEM);
3481
3482         func->function.name    = "Function FS Gadget";
3483
3484         func->function.bind    = ffs_func_bind;
3485         func->function.unbind  = ffs_func_unbind;
3486         func->function.set_alt = ffs_func_set_alt;
3487         func->function.disable = ffs_func_disable;
3488         func->function.setup   = ffs_func_setup;
3489         func->function.req_match = ffs_func_req_match;
3490         func->function.suspend = ffs_func_suspend;
3491         func->function.resume  = ffs_func_resume;
3492         func->function.free_func = ffs_free;
3493
3494         return &func->function;
3495 }
3496
3497 /*
3498  * ffs_lock must be taken by the caller of this function
3499  */
3500 static struct ffs_dev *_ffs_alloc_dev(void)
3501 {
3502         struct ffs_dev *dev;
3503         int ret;
3504
3505         if (_ffs_get_single_dev())
3506                         return ERR_PTR(-EBUSY);
3507
3508         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3509         if (!dev)
3510                 return ERR_PTR(-ENOMEM);
3511
3512         if (list_empty(&ffs_devices)) {
3513                 ret = functionfs_init();
3514                 if (ret) {
3515                         kfree(dev);
3516                         return ERR_PTR(ret);
3517                 }
3518         }
3519
3520         list_add(&dev->entry, &ffs_devices);
3521
3522         return dev;
3523 }
3524
3525 /*
3526  * ffs_lock must be taken by the caller of this function
3527  * The caller is responsible for "name" being available whenever f_fs needs it
3528  */
3529 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
3530 {
3531         struct ffs_dev *existing;
3532
3533         existing = _ffs_do_find_dev(name);
3534         if (existing)
3535                 return -EBUSY;
3536
3537         dev->name = name;
3538
3539         return 0;
3540 }
3541
3542 /*
3543  * The caller is responsible for "name" being available whenever f_fs needs it
3544  */
3545 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3546 {
3547         int ret;
3548
3549         ffs_dev_lock();
3550         ret = _ffs_name_dev(dev, name);
3551         ffs_dev_unlock();
3552
3553         return ret;
3554 }
3555 EXPORT_SYMBOL_GPL(ffs_name_dev);
3556
3557 int ffs_single_dev(struct ffs_dev *dev)
3558 {
3559         int ret;
3560
3561         ret = 0;
3562         ffs_dev_lock();
3563
3564         if (!list_is_singular(&ffs_devices))
3565                 ret = -EBUSY;
3566         else
3567                 dev->single = true;
3568
3569         ffs_dev_unlock();
3570         return ret;
3571 }
3572 EXPORT_SYMBOL_GPL(ffs_single_dev);
3573
3574 /*
3575  * ffs_lock must be taken by the caller of this function
3576  */
3577 static void _ffs_free_dev(struct ffs_dev *dev)
3578 {
3579         list_del(&dev->entry);
3580         if (dev->name_allocated)
3581                 kfree(dev->name);
3582
3583         /* Clear the private_data pointer to stop incorrect dev access */
3584         if (dev->ffs_data)
3585                 dev->ffs_data->private_data = NULL;
3586
3587         kfree(dev);
3588         if (list_empty(&ffs_devices))
3589                 functionfs_cleanup();
3590 }
3591
3592 static void *ffs_acquire_dev(const char *dev_name)
3593 {
3594         struct ffs_dev *ffs_dev;
3595
3596         ENTER();
3597         ffs_dev_lock();
3598
3599         ffs_dev = _ffs_find_dev(dev_name);
3600         if (!ffs_dev)
3601                 ffs_dev = ERR_PTR(-ENOENT);
3602         else if (ffs_dev->mounted)
3603                 ffs_dev = ERR_PTR(-EBUSY);
3604         else if (ffs_dev->ffs_acquire_dev_callback &&
3605             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3606                 ffs_dev = ERR_PTR(-ENOENT);
3607         else
3608                 ffs_dev->mounted = true;
3609
3610         ffs_dev_unlock();
3611         return ffs_dev;
3612 }
3613
3614 static void ffs_release_dev(struct ffs_data *ffs_data)
3615 {
3616         struct ffs_dev *ffs_dev;
3617
3618         ENTER();
3619         ffs_dev_lock();
3620
3621         ffs_dev = ffs_data->private_data;
3622         if (ffs_dev) {
3623                 ffs_dev->mounted = false;
3624
3625                 if (ffs_dev->ffs_release_dev_callback)
3626                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3627         }
3628
3629         ffs_dev_unlock();
3630 }
3631
3632 static int ffs_ready(struct ffs_data *ffs)
3633 {
3634         struct ffs_dev *ffs_obj;
3635         int ret = 0;
3636
3637         ENTER();
3638         ffs_dev_lock();
3639
3640         ffs_obj = ffs->private_data;
3641         if (!ffs_obj) {
3642                 ret = -EINVAL;
3643                 goto done;
3644         }
3645         if (WARN_ON(ffs_obj->desc_ready)) {
3646                 ret = -EBUSY;
3647                 goto done;
3648         }
3649
3650         ffs_obj->desc_ready = true;
3651         ffs_obj->ffs_data = ffs;
3652
3653         if (ffs_obj->ffs_ready_callback) {
3654                 ret = ffs_obj->ffs_ready_callback(ffs);
3655                 if (ret)
3656                         goto done;
3657         }
3658
3659         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3660 done:
3661         ffs_dev_unlock();
3662         return ret;
3663 }
3664
3665 static void ffs_closed(struct ffs_data *ffs)
3666 {
3667         struct ffs_dev *ffs_obj;
3668         struct f_fs_opts *opts;
3669
3670         ENTER();
3671         ffs_dev_lock();
3672
3673         ffs_obj = ffs->private_data;
3674         if (!ffs_obj)
3675                 goto done;
3676
3677         ffs_obj->desc_ready = false;
3678
3679         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3680             ffs_obj->ffs_closed_callback)
3681                 ffs_obj->ffs_closed_callback(ffs);
3682
3683         if (ffs_obj->opts)
3684                 opts = ffs_obj->opts;
3685         else
3686                 goto done;
3687
3688         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3689             || !atomic_read(&opts->func_inst.group.cg_item.ci_kref.refcount))
3690                 goto done;
3691
3692         unregister_gadget_item(ffs_obj->opts->
3693                                func_inst.group.cg_item.ci_parent->ci_parent);
3694 done:
3695         ffs_dev_unlock();
3696 }
3697
3698 /* Misc helper functions ****************************************************/
3699
3700 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3701 {
3702         return nonblock
3703                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3704                 : mutex_lock_interruptible(mutex);
3705 }
3706
3707 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3708 {
3709         char *data;
3710
3711         if (unlikely(!len))
3712                 return NULL;
3713
3714         data = kmalloc(len, GFP_KERNEL);
3715         if (unlikely(!data))
3716                 return ERR_PTR(-ENOMEM);
3717
3718         if (unlikely(copy_from_user(data, buf, len))) {
3719                 kfree(data);
3720                 return ERR_PTR(-EFAULT);
3721         }
3722
3723         pr_vdebug("Buffer from user space:\n");
3724         ffs_dump_mem("", data, len);
3725
3726         return data;
3727 }
3728
3729 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3730 MODULE_LICENSE("GPL");
3731 MODULE_AUTHOR("Michal Nazarewicz");