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 stream_open(inode, file);
 612 }
 613
 614 static int ffs_ep0_release(struct inode *inode, struct file *file)
 615 {
 616         struct ffs_data *ffs = file->private_data;
 617
 618         ENTER();
 619
 620         ffs_data_closed(ffs);
 621
 622         return 0;
 623 }
 624
 625 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 626 {
 627         struct ffs_data *ffs = file->private_data;
 628         struct usb_gadget *gadget = ffs->gadget;
 629         long ret;
 630
 631         ENTER();
 632
 633         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 634                 struct ffs_function *func = ffs->func;
 635                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 636         } else if (gadget && gadget->ops->ioctl) {
 637                 ret = gadget->ops->ioctl(gadget, code, value);
 638         } else {
 639                 ret = -ENOTTY;
 640         }
 641
 642         return ret;
 643 }
 644
 645 static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
 646 {
 647         struct ffs_data *ffs = file->private_data;
 648         unsigned int mask = POLLWRNORM;
 649         int ret;
 650
 651         poll_wait(file, &ffs->ev.waitq, wait);
 652
 653         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 654         if (unlikely(ret < 0))
 655                 return mask;
 656
 657         switch (ffs->state) {
 658         case FFS_READ_DESCRIPTORS:
 659         case FFS_READ_STRINGS:
 660                 mask |= POLLOUT;
 661                 break;
 662
 663         case FFS_ACTIVE:
 664                 switch (ffs->setup_state) {
 665                 case FFS_NO_SETUP:
 666                         if (ffs->ev.count)
 667                                 mask |= POLLIN;
 668                         break;
 669
 670                 case FFS_SETUP_PENDING:
 671                 case FFS_SETUP_CANCELLED:
 672                         mask |= (POLLIN | POLLOUT);
 673                         break;
 674                 }
 675         case FFS_CLOSING:
 676                 break;
 677         case FFS_DEACTIVATED:
 678                 break;
 679         }
 680
 681         mutex_unlock(&ffs->mutex);
 682
 683         return mask;
 684 }
 685
 686 static const struct file_operations ffs_ep0_operations = {
 687         .llseek =       no_llseek,
 688
 689         .open =         ffs_ep0_open,
 690         .write =        ffs_ep0_write,
 691         .read =         ffs_ep0_read,
 692         .release =      ffs_ep0_release,
 693         .unlocked_ioctl =       ffs_ep0_ioctl,
 694         .poll =         ffs_ep0_poll,
 695 };
 696
 697
 698 /* "Normal" endpoints operations ********************************************/
 699
 700 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 701 {
 702         ENTER();
 703         if (likely(req->context)) {
 704                 struct ffs_ep *ep = _ep->driver_data;
 705                 ep->status = req->status ? req->status : req->actual;
 706                 complete(req->context);
 707         }
 708 }
 709
 710 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 711 {
 712         ssize_t ret = copy_to_iter(data, data_len, iter);
 713         if (likely(ret == data_len))
 714                 return ret;
 715
 716         if (unlikely(iov_iter_count(iter)))
 717                 return -EFAULT;
 718
 719         /*
 720          * Dear user space developer!
 721          *
 722          * TL;DR: To stop getting below error message in your kernel log, change
 723          * user space code using functionfs to align read buffers to a max
 724          * packet size.
 725          *
 726          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 727          * packet size.  When unaligned buffer is passed to functionfs, it
 728          * internally uses a larger, aligned buffer so that such UDCs are happy.
 729          *
 730          * Unfortunately, this means that host may send more data than was
 731          * requested in read(2) system call.  f_fs doesn’t know what to do with
 732          * that excess data so it simply drops it.
 733          *
 734          * Was the buffer aligned in the first place, no such problem would
 735          * happen.
 736          *
 737          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 738          * by splitting a request into multiple parts.  This splitting may still
 739          * be a problem though so it’s likely best to align the buffer
 740          * regardless of it being AIO or not..
 741          *
 742          * This only affects OUT endpoints, i.e. reading data with a read(2),
 743          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 744          * affected.
 745          */
 746         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 747                "Align read buffer size to max packet size to avoid the problem.\n",
 748                data_len, ret);
 749
 750         return ret;
 751 }
 752
 753 static void ffs_user_copy_worker(struct work_struct *work)
 754 {
 755         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 756                                                    work);
 757         int ret = io_data->req->status ? io_data->req->status :
 758                                          io_data->req->actual;
 759         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 760
 761         if (io_data->read && ret > 0) {
 762                 mm_segment_t oldfs = get_fs();
 763
 764                 set_fs(USER_DS);
 765                 use_mm(io_data->mm);
 766                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 767                 unuse_mm(io_data->mm);
 768                 set_fs(oldfs);
 769         }
 770
 771         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 772
 773         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 774                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 775
 776         usb_ep_free_request(io_data->ep, io_data->req);
 777
 778         if (io_data->read)
 779                 kfree(io_data->to_free);
 780         kfree(io_data->buf);
 781         kfree(io_data);
 782 }
 783
 784 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 785                                          struct usb_request *req)
 786 {
 787         struct ffs_io_data *io_data = req->context;
 788
 789         ENTER();
 790
 791         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 792         schedule_work(&io_data->work);
 793 }
 794
 795 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 796 {
 797         /*
 798          * See comment in struct ffs_epfile for full read_buffer pointer
 799          * synchronisation story.
 800          */
 801         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 802         if (buf && buf != READ_BUFFER_DROP)
 803                 kfree(buf);
 804 }
 805
 806 /* Assumes epfile->mutex is held. */
 807 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 808                                           struct iov_iter *iter)
 809 {
 810         /*
 811          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 812          * the buffer while we are using it.  See comment in struct ffs_epfile
 813          * for full read_buffer pointer synchronisation story.
 814          */
 815         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 816         ssize_t ret;
 817         if (!buf || buf == READ_BUFFER_DROP)
 818                 return 0;
 819
 820         ret = copy_to_iter(buf->data, buf->length, iter);
 821         if (buf->length == ret) {
 822                 kfree(buf);
 823                 return ret;
 824         }
 825
 826         if (unlikely(iov_iter_count(iter))) {
 827                 ret = -EFAULT;
 828         } else {
 829                 buf->length -= ret;
 830                 buf->data += ret;
 831         }
 832
 833         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 834                 kfree(buf);
 835
 836         return ret;
 837 }
 838
 839 /* Assumes epfile->mutex is held. */
 840 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 841                                       void *data, int data_len,
 842                                       struct iov_iter *iter)
 843 {
 844         struct ffs_buffer *buf;
 845
 846         ssize_t ret = copy_to_iter(data, data_len, iter);
 847         if (likely(data_len == ret))
 848                 return ret;
 849
 850         if (unlikely(iov_iter_count(iter)))
 851                 return -EFAULT;
 852
 853         /* See ffs_copy_to_iter for more context. */
 854         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 855                 data_len, ret);
 856
 857         data_len -= ret;
 858         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 859         if (!buf)
 860                 return -ENOMEM;
 861         buf->length = data_len;
 862         buf->data = buf->storage;
 863         memcpy(buf->storage, data + ret, data_len);
 864
 865         /*
 866          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 867          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 868          * in struct ffs_epfile for full read_buffer pointer synchronisation
 869          * story.
 870          */
 871         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 872                 kfree(buf);
 873
 874         return ret;
 875 }
 876
 877 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 878 {
 879         struct ffs_epfile *epfile = file->private_data;
 880         struct usb_request *req;
 881         struct ffs_ep *ep;
 882         char *data = NULL;
 883         ssize_t ret, data_len = -EINVAL;
 884         int halt;
 885
 886         /* Are we still active? */
 887         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 888                 return -ENODEV;
 889
 890         /* Wait for endpoint to be enabled */
 891         ep = epfile->ep;
 892         if (!ep) {
 893                 if (file->f_flags & O_NONBLOCK)
 894                         return -EAGAIN;
 895
 896                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
 897                 if (ret)
 898                         return -EINTR;
 899         }
 900
 901         /* Do we halt? */
 902         halt = (!io_data->read == !epfile->in);
 903         if (halt && epfile->isoc)
 904                 return -EINVAL;
 905
 906         /* We will be using request and read_buffer */
 907         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 908         if (unlikely(ret))
 909                 goto error;
 910
 911         /* Allocate & copy */
 912         if (!halt) {
 913                 struct usb_gadget *gadget;
 914
 915                 /*
 916                  * Do we have buffered data from previous partial read?  Check
 917                  * that for synchronous case only because we do not have
 918                  * facility to ‘wake up’ a pending asynchronous read and push
 919                  * buffered data to it which we would need to make things behave
 920                  * consistently.
 921                  */
 922                 if (!io_data->aio && io_data->read) {
 923                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 924                         if (ret)
 925                                 goto error_mutex;
 926                 }
 927
 928                 /*
 929                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 930                  * before the waiting completes, so do not assign to 'gadget'
 931                  * earlier
 932                  */
 933                 gadget = epfile->ffs->gadget;
 934
 935                 spin_lock_irq(&epfile->ffs->eps_lock);
 936                 /* In the meantime, endpoint got disabled or changed. */
 937                 if (epfile->ep != ep) {
 938                         ret = -ESHUTDOWN;
 939                         goto error_lock;
 940                 }
 941                 data_len = iov_iter_count(&io_data->data);
 942                 /*
 943                  * Controller may require buffer size to be aligned to
 944                  * maxpacketsize of an out endpoint.
 945                  */
 946                 if (io_data->read)
 947                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
 948                 spin_unlock_irq(&epfile->ffs->eps_lock);
 949
 950                 data = kmalloc(data_len, GFP_KERNEL);
 951                 if (unlikely(!data)) {
 952                         ret = -ENOMEM;
 953                         goto error_mutex;
 954                 }
 955                 if (!io_data->read &&
 956                     copy_from_iter(data, data_len, &io_data->data) != data_len) {
 957                         ret = -EFAULT;
 958                         goto error_mutex;
 959                 }
 960         }
 961
 962         spin_lock_irq(&epfile->ffs->eps_lock);
 963
 964         if (epfile->ep != ep) {
 965                 /* In the meantime, endpoint got disabled or changed. */
 966                 ret = -ESHUTDOWN;
 967         } else if (halt) {
 968                 /* Halt */
 969                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 970                         usb_ep_set_halt(ep->ep);
 971                 ret = -EBADMSG;
 972         } else if (unlikely(data_len == -EINVAL)) {
 973                 /*
 974                  * Sanity Check: even though data_len can't be used
 975                  * uninitialized at the time I write this comment, some
 976                  * compilers complain about this situation.
 977                  * In order to keep the code clean from warnings, data_len is
 978                  * being initialized to -EINVAL during its declaration, which
 979                  * means we can't rely on compiler anymore to warn no future
 980                  * changes won't result in data_len being used uninitialized.
 981                  * For such reason, we're adding this redundant sanity check
 982                  * here.
 983                  */
 984                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
 985                 ret = -EINVAL;
 986         } else if (!io_data->aio) {
 987                 DECLARE_COMPLETION_ONSTACK(done);
 988                 bool interrupted = false;
 989
 990                 req = ep->req;
 991                 req->buf      = data;
 992                 req->length   = data_len;
 993
 994                 req->context  = &done;
 995                 req->complete = ffs_epfile_io_complete;
 996
 997                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 998                 if (unlikely(ret < 0))
 999                         goto error_lock;
1000
1001                 spin_unlock_irq(&epfile->ffs->eps_lock);
1002
1003                 if (unlikely(wait_for_completion_interruptible(&done))) {
1004                         /*
1005                          * To avoid race condition with ffs_epfile_io_complete,
1006                          * dequeue the request first then check
1007                          * status. usb_ep_dequeue API should guarantee no race
1008                          * condition with req->complete callback.
1009                          */
1010                         usb_ep_dequeue(ep->ep, req);
1011                         wait_for_completion(&done);
1012                         interrupted = ep->status < 0;
1013                 }
1014
1015                 if (interrupted)
1016                         ret = -EINTR;
1017                 else if (io_data->read && ep->status > 0)
1018                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1019                                                      &io_data->data);
1020                 else
1021                         ret = ep->status;
1022                 goto error_mutex;
1023         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1024                 ret = -ENOMEM;
1025         } else {
1026                 req->buf      = data;
1027                 req->length   = data_len;
1028
1029                 io_data->buf = data;
1030                 io_data->ep = ep->ep;
1031                 io_data->req = req;
1032                 io_data->ffs = epfile->ffs;
1033
1034                 req->context  = io_data;
1035                 req->complete = ffs_epfile_async_io_complete;
1036
1037                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1038                 if (unlikely(ret)) {
1039                         io_data->req = NULL;
1040                         usb_ep_free_request(ep->ep, req);
1041                         goto error_lock;
1042                 }
1043
1044                 ret = -EIOCBQUEUED;
1045                 /*
1046                  * Do not kfree the buffer in this function.  It will be freed
1047                  * by ffs_user_copy_worker.
1048                  */
1049                 data = NULL;
1050         }
1051
1052 error_lock:
1053         spin_unlock_irq(&epfile->ffs->eps_lock);
1054 error_mutex:
1055         mutex_unlock(&epfile->mutex);
1056 error:
1057         kfree(data);
1058         return ret;
1059 }
1060
1061 static int
1062 ffs_epfile_open(struct inode *inode, struct file *file)
1063 {
1064         struct ffs_epfile *epfile = inode->i_private;
1065
1066         ENTER();
1067
1068         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1069                 return -ENODEV;
1070
1071         file->private_data = epfile;
1072         ffs_data_opened(epfile->ffs);
1073
1074         return stream_open(inode, file);
1075 }
1076
1077 static int ffs_aio_cancel(struct kiocb *kiocb)
1078 {
1079         struct ffs_io_data *io_data = kiocb->private;
1080         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1081         unsigned long flags;
1082         int value;
1083
1084         ENTER();
1085
1086         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1087
1088         if (likely(io_data && io_data->ep && io_data->req))
1089                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1090         else
1091                 value = -EINVAL;
1092
1093         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1094
1095         return value;
1096 }
1097
1098 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1099 {
1100         struct ffs_io_data io_data, *p = &io_data;
1101         ssize_t res;
1102
1103         ENTER();
1104
1105         if (!is_sync_kiocb(kiocb)) {
1106                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1107                 if (unlikely(!p))
1108                         return -ENOMEM;
1109                 p->aio = true;
1110         } else {
1111                 memset(p, 0, sizeof(*p));
1112                 p->aio = false;
1113         }
1114
1115         p->read = false;
1116         p->kiocb = kiocb;
1117         p->data = *from;
1118         p->mm = current->mm;
1119
1120         kiocb->private = p;
1121
1122         if (p->aio)
1123                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1124
1125         res = ffs_epfile_io(kiocb->ki_filp, p);
1126         if (res == -EIOCBQUEUED)
1127                 return res;
1128         if (p->aio)
1129                 kfree(p);
1130         else
1131                 *from = p->data;
1132         return res;
1133 }
1134
1135 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1136 {
1137         struct ffs_io_data io_data, *p = &io_data;
1138         ssize_t res;
1139
1140         ENTER();
1141
1142         if (!is_sync_kiocb(kiocb)) {
1143                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1144                 if (unlikely(!p))
1145                         return -ENOMEM;
1146                 p->aio = true;
1147         } else {
1148                 memset(p, 0, sizeof(*p));
1149                 p->aio = false;
1150         }
1151
1152         p->read = true;
1153         p->kiocb = kiocb;
1154         if (p->aio) {
1155                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1156                 if (!p->to_free) {
1157                         kfree(p);
1158                         return -ENOMEM;
1159                 }
1160         } else {
1161                 p->data = *to;
1162                 p->to_free = NULL;
1163         }
1164         p->mm = current->mm;
1165
1166         kiocb->private = p;
1167
1168         if (p->aio)
1169                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1170
1171         res = ffs_epfile_io(kiocb->ki_filp, p);
1172         if (res == -EIOCBQUEUED)
1173                 return res;
1174
1175         if (p->aio) {
1176                 kfree(p->to_free);
1177                 kfree(p);
1178         } else {
1179                 *to = p->data;
1180         }
1181         return res;
1182 }
1183
1184 static int
1185 ffs_epfile_release(struct inode *inode, struct file *file)
1186 {
1187         struct ffs_epfile *epfile = inode->i_private;
1188
1189         ENTER();
1190
1191         __ffs_epfile_read_buffer_free(epfile);
1192         ffs_data_closed(epfile->ffs);
1193
1194         return 0;
1195 }
1196
1197 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1198                              unsigned long value)
1199 {
1200         struct ffs_epfile *epfile = file->private_data;
1201         int ret;
1202
1203         ENTER();
1204
1205         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1206                 return -ENODEV;
1207
1208         spin_lock_irq(&epfile->ffs->eps_lock);
1209         if (likely(epfile->ep)) {
1210                 switch (code) {
1211                 case FUNCTIONFS_FIFO_STATUS:
1212                         ret = usb_ep_fifo_status(epfile->ep->ep);
1213                         break;
1214                 case FUNCTIONFS_FIFO_FLUSH:
1215                         usb_ep_fifo_flush(epfile->ep->ep);
1216                         ret = 0;
1217                         break;
1218                 case FUNCTIONFS_CLEAR_HALT:
1219                         ret = usb_ep_clear_halt(epfile->ep->ep);
1220                         break;
1221                 case FUNCTIONFS_ENDPOINT_REVMAP:
1222                         ret = epfile->ep->num;
1223                         break;
1224                 case FUNCTIONFS_ENDPOINT_DESC:
1225                 {
1226                         int desc_idx;
1227                         struct usb_endpoint_descriptor desc1, *desc;
1228
1229                         switch (epfile->ffs->gadget->speed) {
1230                         case USB_SPEED_SUPER:
1231                         case USB_SPEED_SUPER_PLUS:
1232                                 desc_idx = 2;
1233                                 break;
1234                         case USB_SPEED_HIGH:
1235                                 desc_idx = 1;
1236                                 break;
1237                         default:
1238                                 desc_idx = 0;
1239                         }
1240
1241                         desc = epfile->ep->descs[desc_idx];
1242                         memcpy(&desc1, desc, desc->bLength);
1243
1244                         spin_unlock_irq(&epfile->ffs->eps_lock);
1245                         ret = copy_to_user((void *)value, &desc1, desc1.bLength);
1246                         if (ret)
1247                                 ret = -EFAULT;
1248                         return ret;
1249                 }
1250                 default:
1251                         ret = -ENOTTY;
1252                 }
1253         } else {
1254                 ret = -ENODEV;
1255         }
1256         spin_unlock_irq(&epfile->ffs->eps_lock);
1257
1258         return ret;
1259 }
1260
1261 static const struct file_operations ffs_epfile_operations = {
1262         .llseek =       no_llseek,
1263
1264         .open =         ffs_epfile_open,
1265         .write_iter =   ffs_epfile_write_iter,
1266         .read_iter =    ffs_epfile_read_iter,
1267         .release =      ffs_epfile_release,
1268         .unlocked_ioctl =       ffs_epfile_ioctl,
1269 };
1270
1271
1272 /* File system and super block operations ***********************************/
1273
1274 /*
1275  * Mounting the file system creates a controller file, used first for
1276  * function configuration then later for event monitoring.
1277  */
1278
1279 static struct inode *__must_check
1280 ffs_sb_make_inode(struct super_block *sb, void *data,
1281                   const struct file_operations *fops,
1282                   const struct inode_operations *iops,
1283                   struct ffs_file_perms *perms)
1284 {
1285         struct inode *inode;
1286
1287         ENTER();
1288
1289         inode = new_inode(sb);
1290
1291         if (likely(inode)) {
1292                 struct timespec ts = current_time(inode);
1293
1294                 inode->i_ino     = get_next_ino();
1295                 inode->i_mode    = perms->mode;
1296                 inode->i_uid     = perms->uid;
1297                 inode->i_gid     = perms->gid;
1298                 inode->i_atime   = ts;
1299                 inode->i_mtime   = ts;
1300                 inode->i_ctime   = ts;
1301                 inode->i_private = data;
1302                 if (fops)
1303                         inode->i_fop = fops;
1304                 if (iops)
1305                         inode->i_op  = iops;
1306         }
1307
1308         return inode;
1309 }
1310
1311 /* Create "regular" file */
1312 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1313                                         const char *name, void *data,
1314                                         const struct file_operations *fops)
1315 {
1316         struct ffs_data *ffs = sb->s_fs_info;
1317         struct dentry   *dentry;
1318         struct inode    *inode;
1319
1320         ENTER();
1321
1322         dentry = d_alloc_name(sb->s_root, name);
1323         if (unlikely(!dentry))
1324                 return NULL;
1325
1326         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1327         if (unlikely(!inode)) {
1328                 dput(dentry);
1329                 return NULL;
1330         }
1331
1332         d_add(dentry, inode);
1333         return dentry;
1334 }
1335
1336 /* Super block */
1337 static const struct super_operations ffs_sb_operations = {
1338         .statfs =       simple_statfs,
1339         .drop_inode =   generic_delete_inode,
1340 };
1341
1342 struct ffs_sb_fill_data {
1343         struct ffs_file_perms perms;
1344         umode_t root_mode;
1345         const char *dev_name;
1346         bool no_disconnect;
1347         struct ffs_data *ffs_data;
1348 };
1349
1350 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1351 {
1352         struct ffs_sb_fill_data *data = _data;
1353         struct inode    *inode;
1354         struct ffs_data *ffs = data->ffs_data;
1355
1356         ENTER();
1357
1358         ffs->sb              = sb;
1359         data->ffs_data       = NULL;
1360         sb->s_fs_info        = ffs;
1361         sb->s_blocksize      = PAGE_SIZE;
1362         sb->s_blocksize_bits = PAGE_SHIFT;
1363         sb->s_magic          = FUNCTIONFS_MAGIC;
1364         sb->s_op             = &ffs_sb_operations;
1365         sb->s_time_gran      = 1;
1366
1367         /* Root inode */
1368         data->perms.mode = data->root_mode;
1369         inode = ffs_sb_make_inode(sb, NULL,
1370                                   &simple_dir_operations,
1371                                   &simple_dir_inode_operations,
1372                                   &data->perms);
1373         sb->s_root = d_make_root(inode);
1374         if (unlikely(!sb->s_root))
1375                 return -ENOMEM;
1376
1377         /* EP0 file */
1378         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1379                                          &ffs_ep0_operations)))
1380                 return -ENOMEM;
1381
1382         return 0;
1383 }
1384
1385 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1386 {
1387         ENTER();
1388
1389         if (!opts || !*opts)
1390                 return 0;
1391
1392         for (;;) {
1393                 unsigned long value;
1394                 char *eq, *comma;
1395
1396                 /* Option limit */
1397                 comma = strchr(opts, ',');
1398                 if (comma)
1399                         *comma = 0;
1400
1401                 /* Value limit */
1402                 eq = strchr(opts, '=');
1403                 if (unlikely(!eq)) {
1404                         pr_err("'=' missing in %s\n", opts);
1405                         return -EINVAL;
1406                 }
1407                 *eq = 0;
1408
1409                 /* Parse value */
1410                 if (kstrtoul(eq + 1, 0, &value)) {
1411                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1412                         return -EINVAL;
1413                 }
1414
1415                 /* Interpret option */
1416                 switch (eq - opts) {
1417                 case 13:
1418                         if (!memcmp(opts, "no_disconnect", 13))
1419                                 data->no_disconnect = !!value;
1420                         else
1421                                 goto invalid;
1422                         break;
1423                 case 5:
1424                         if (!memcmp(opts, "rmode", 5))
1425                                 data->root_mode  = (value & 0555) | S_IFDIR;
1426                         else if (!memcmp(opts, "fmode", 5))
1427                                 data->perms.mode = (value & 0666) | S_IFREG;
1428                         else
1429                                 goto invalid;
1430                         break;
1431
1432                 case 4:
1433                         if (!memcmp(opts, "mode", 4)) {
1434                                 data->root_mode  = (value & 0555) | S_IFDIR;
1435                                 data->perms.mode = (value & 0666) | S_IFREG;
1436                         } else {
1437                                 goto invalid;
1438                         }
1439                         break;
1440
1441                 case 3:
1442                         if (!memcmp(opts, "uid", 3)) {
1443                                 data->perms.uid = make_kuid(current_user_ns(), value);
1444                                 if (!uid_valid(data->perms.uid)) {
1445                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1446                                         return -EINVAL;
1447                                 }
1448                         } else if (!memcmp(opts, "gid", 3)) {
1449                                 data->perms.gid = make_kgid(current_user_ns(), value);
1450                                 if (!gid_valid(data->perms.gid)) {
1451                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1452                                         return -EINVAL;
1453                                 }
1454                         } else {
1455                                 goto invalid;
1456                         }
1457                         break;
1458
1459                 default:
1460 invalid:
1461                         pr_err("%s: invalid option\n", opts);
1462                         return -EINVAL;
1463                 }
1464
1465                 /* Next iteration */
1466                 if (!comma)
1467                         break;
1468                 opts = comma + 1;
1469         }
1470
1471         return 0;
1472 }
1473
1474 /* "mount -t functionfs dev_name /dev/function" ends up here */
1475
1476 static struct dentry *
1477 ffs_fs_mount(struct file_system_type *t, int flags,
1478               const char *dev_name, void *opts)
1479 {
1480         struct ffs_sb_fill_data data = {
1481                 .perms = {
1482                         .mode = S_IFREG | 0600,
1483                         .uid = GLOBAL_ROOT_UID,
1484                         .gid = GLOBAL_ROOT_GID,
1485                 },
1486                 .root_mode = S_IFDIR | 0500,
1487                 .no_disconnect = false,
1488         };
1489         struct dentry *rv;
1490         int ret;
1491         void *ffs_dev;
1492         struct ffs_data *ffs;
1493
1494         ENTER();
1495
1496         ret = ffs_fs_parse_opts(&data, opts);
1497         if (unlikely(ret < 0))
1498                 return ERR_PTR(ret);
1499
1500         ffs = ffs_data_new();
1501         if (unlikely(!ffs))
1502                 return ERR_PTR(-ENOMEM);
1503         ffs->file_perms = data.perms;
1504         ffs->no_disconnect = data.no_disconnect;
1505
1506         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1507         if (unlikely(!ffs->dev_name)) {
1508                 ffs_data_put(ffs);
1509                 return ERR_PTR(-ENOMEM);
1510         }
1511
1512         ffs_dev = ffs_acquire_dev(dev_name);
1513         if (IS_ERR(ffs_dev)) {
1514                 ffs_data_put(ffs);
1515                 return ERR_CAST(ffs_dev);
1516         }
1517         ffs->private_data = ffs_dev;
1518         data.ffs_data = ffs;
1519
1520         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1521         if (IS_ERR(rv) && data.ffs_data) {
1522                 ffs_release_dev(data.ffs_data);
1523                 ffs_data_put(data.ffs_data);
1524         }
1525         return rv;
1526 }
1527
1528 static void
1529 ffs_fs_kill_sb(struct super_block *sb)
1530 {
1531         ENTER();
1532
1533         kill_litter_super(sb);
1534         if (sb->s_fs_info) {
1535                 ffs_release_dev(sb->s_fs_info);
1536                 ffs_data_closed(sb->s_fs_info);
1537         }
1538 }
1539
1540 static struct file_system_type ffs_fs_type = {
1541         .owner          = THIS_MODULE,
1542         .name           = "functionfs",
1543         .mount          = ffs_fs_mount,
1544         .kill_sb        = ffs_fs_kill_sb,
1545 };
1546 MODULE_ALIAS_FS("functionfs");
1547
1548
1549 /* Driver's main init/cleanup functions *************************************/
1550
1551 static int functionfs_init(void)
1552 {
1553         int ret;
1554
1555         ENTER();
1556
1557         ret = register_filesystem(&ffs_fs_type);
1558         if (likely(!ret))
1559                 pr_info("file system registered\n");
1560         else
1561                 pr_err("failed registering file system (%d)\n", ret);
1562
1563         return ret;
1564 }
1565
1566 static void functionfs_cleanup(void)
1567 {
1568         ENTER();
1569
1570         pr_info("unloading\n");
1571         unregister_filesystem(&ffs_fs_type);
1572 }
1573
1574
1575 /* ffs_data and ffs_function construction and destruction code **************/
1576
1577 static void ffs_data_clear(struct ffs_data *ffs);
1578 static void ffs_data_reset(struct ffs_data *ffs);
1579
1580 static void ffs_data_get(struct ffs_data *ffs)
1581 {
1582         ENTER();
1583
1584         atomic_inc(&ffs->ref);
1585 }
1586
1587 static void ffs_data_opened(struct ffs_data *ffs)
1588 {
1589         ENTER();
1590
1591         atomic_inc(&ffs->ref);
1592         if (atomic_add_return(1, &ffs->opened) == 1 &&
1593                         ffs->state == FFS_DEACTIVATED) {
1594                 ffs->state = FFS_CLOSING;
1595                 ffs_data_reset(ffs);
1596         }
1597 }
1598
1599 static void ffs_data_put(struct ffs_data *ffs)
1600 {
1601         ENTER();
1602
1603         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1604                 pr_info("%s(): freeing\n", __func__);
1605                 ffs_data_clear(ffs);
1606                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1607                        waitqueue_active(&ffs->ep0req_completion.wait));
1608                 kfree(ffs->dev_name);
1609                 kfree(ffs);
1610         }
1611 }
1612
1613 static void ffs_data_closed(struct ffs_data *ffs)
1614 {
1615         ENTER();
1616
1617         if (atomic_dec_and_test(&ffs->opened)) {
1618                 if (ffs->no_disconnect) {
1619                         ffs->state = FFS_DEACTIVATED;
1620                         if (ffs->epfiles) {
1621                                 ffs_epfiles_destroy(ffs->epfiles,
1622                                                    ffs->eps_count);
1623                                 ffs->epfiles = NULL;
1624                         }
1625                         if (ffs->setup_state == FFS_SETUP_PENDING)
1626                                 __ffs_ep0_stall(ffs);
1627                 } else {
1628                         ffs->state = FFS_CLOSING;
1629                         ffs_data_reset(ffs);
1630                 }
1631         }
1632         if (atomic_read(&ffs->opened) < 0) {
1633                 ffs->state = FFS_CLOSING;
1634                 ffs_data_reset(ffs);
1635         }
1636
1637         ffs_data_put(ffs);
1638 }
1639
1640 static struct ffs_data *ffs_data_new(void)
1641 {
1642         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1643         if (unlikely(!ffs))
1644                 return NULL;
1645
1646         ENTER();
1647
1648         atomic_set(&ffs->ref, 1);
1649         atomic_set(&ffs->opened, 0);
1650         ffs->state = FFS_READ_DESCRIPTORS;
1651         mutex_init(&ffs->mutex);
1652         spin_lock_init(&ffs->eps_lock);
1653         init_waitqueue_head(&ffs->ev.waitq);
1654         init_completion(&ffs->ep0req_completion);
1655
1656         /* XXX REVISIT need to update it in some places, or do we? */
1657         ffs->ev.can_stall = 1;
1658
1659         return ffs;
1660 }
1661
1662 static void ffs_data_clear(struct ffs_data *ffs)
1663 {
1664         ENTER();
1665
1666         ffs_closed(ffs);
1667
1668         BUG_ON(ffs->gadget);
1669
1670         if (ffs->epfiles) {
1671                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1672                 ffs->epfiles = NULL;
1673         }
1674
1675         if (ffs->ffs_eventfd) {
1676                 eventfd_ctx_put(ffs->ffs_eventfd);
1677                 ffs->ffs_eventfd = NULL;
1678         }
1679
1680         kfree(ffs->raw_descs_data);
1681         kfree(ffs->raw_strings);
1682         kfree(ffs->stringtabs);
1683 }
1684
1685 static void ffs_data_reset(struct ffs_data *ffs)
1686 {
1687         ENTER();
1688
1689         ffs_data_clear(ffs);
1690
1691         ffs->raw_descs_data = NULL;
1692         ffs->raw_descs = NULL;
1693         ffs->raw_strings = NULL;
1694         ffs->stringtabs = NULL;
1695
1696         ffs->raw_descs_length = 0;
1697         ffs->fs_descs_count = 0;
1698         ffs->hs_descs_count = 0;
1699         ffs->ss_descs_count = 0;
1700
1701         ffs->strings_count = 0;
1702         ffs->interfaces_count = 0;
1703         ffs->eps_count = 0;
1704
1705         ffs->ev.count = 0;
1706
1707         ffs->state = FFS_READ_DESCRIPTORS;
1708         ffs->setup_state = FFS_NO_SETUP;
1709         ffs->flags = 0;
1710
1711         ffs->ms_os_descs_ext_prop_count = 0;
1712         ffs->ms_os_descs_ext_prop_name_len = 0;
1713         ffs->ms_os_descs_ext_prop_data_len = 0;
1714 }
1715
1716
1717 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1718 {
1719         struct usb_gadget_strings **lang;
1720         int first_id;
1721
1722         ENTER();
1723
1724         if (WARN_ON(ffs->state != FFS_ACTIVE
1725                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1726                 return -EBADFD;
1727
1728         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1729         if (unlikely(first_id < 0))
1730                 return first_id;
1731
1732         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1733         if (unlikely(!ffs->ep0req))
1734                 return -ENOMEM;
1735         ffs->ep0req->complete = ffs_ep0_complete;
1736         ffs->ep0req->context = ffs;
1737
1738         lang = ffs->stringtabs;
1739         if (lang) {
1740                 for (; *lang; ++lang) {
1741                         struct usb_string *str = (*lang)->strings;
1742                         int id = first_id;
1743                         for (; str->s; ++id, ++str)
1744                                 str->id = id;
1745                 }
1746         }
1747
1748         ffs->gadget = cdev->gadget;
1749         ffs_data_get(ffs);
1750         return 0;
1751 }
1752
1753 static void functionfs_unbind(struct ffs_data *ffs)
1754 {
1755         ENTER();
1756
1757         if (!WARN_ON(!ffs->gadget)) {
1758                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1759                 ffs->ep0req = NULL;
1760                 ffs->gadget = NULL;
1761                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1762                 ffs_data_put(ffs);
1763         }
1764 }
1765
1766 static int ffs_epfiles_create(struct ffs_data *ffs)
1767 {
1768         struct ffs_epfile *epfile, *epfiles;
1769         unsigned i, count;
1770
1771         ENTER();
1772
1773         count = ffs->eps_count;
1774         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1775         if (!epfiles)
1776                 return -ENOMEM;
1777
1778         epfile = epfiles;
1779         for (i = 1; i <= count; ++i, ++epfile) {
1780                 epfile->ffs = ffs;
1781                 mutex_init(&epfile->mutex);
1782                 init_waitqueue_head(&epfile->wait);
1783                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1784                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1785                 else
1786                         sprintf(epfile->name, "ep%u", i);
1787                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1788                                                  epfile,
1789                                                  &ffs_epfile_operations);
1790                 if (unlikely(!epfile->dentry)) {
1791                         ffs_epfiles_destroy(epfiles, i - 1);
1792                         return -ENOMEM;
1793                 }
1794         }
1795
1796         ffs->epfiles = epfiles;
1797         return 0;
1798 }
1799
1800 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1801 {
1802         struct ffs_epfile *epfile = epfiles;
1803
1804         ENTER();
1805
1806         for (; count; --count, ++epfile) {
1807                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1808                        waitqueue_active(&epfile->wait));
1809                 if (epfile->dentry) {
1810                         d_delete(epfile->dentry);
1811                         dput(epfile->dentry);
1812                         epfile->dentry = NULL;
1813                 }
1814         }
1815
1816         kfree(epfiles);
1817 }
1818
1819 static void ffs_func_eps_disable(struct ffs_function *func)
1820 {
1821         struct ffs_ep *ep         = func->eps;
1822         struct ffs_epfile *epfile = func->ffs->epfiles;
1823         unsigned count            = func->ffs->eps_count;
1824         unsigned long flags;
1825
1826         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1827         do {
1828                 /* pending requests get nuked */
1829                 if (likely(ep->ep))
1830                         usb_ep_disable(ep->ep);
1831                 ++ep;
1832
1833                 if (epfile) {
1834                         epfile->ep = NULL;
1835                         __ffs_epfile_read_buffer_free(epfile);
1836                         ++epfile;
1837                 }
1838         } while (--count);
1839         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1840 }
1841
1842 static int ffs_func_eps_enable(struct ffs_function *func)
1843 {
1844         struct ffs_data *ffs      = func->ffs;
1845         struct ffs_ep *ep         = func->eps;
1846         struct ffs_epfile *epfile = ffs->epfiles;
1847         unsigned count            = ffs->eps_count;
1848         unsigned long flags;
1849         int ret = 0;
1850
1851         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1852         do {
1853                 struct usb_endpoint_descriptor *ds;
1854                 struct usb_ss_ep_comp_descriptor *comp_desc = NULL;
1855                 int needs_comp_desc = false;
1856                 int desc_idx;
1857
1858                 if (ffs->gadget->speed == USB_SPEED_SUPER) {
1859                         desc_idx = 2;
1860                         needs_comp_desc = true;
1861                 } else if (ffs->gadget->speed == USB_SPEED_HIGH)
1862                         desc_idx = 1;
1863                 else
1864                         desc_idx = 0;
1865
1866                 /* fall-back to lower speed if desc missing for current speed */
1867                 do {
1868                         ds = ep->descs[desc_idx];
1869                 } while (!ds && --desc_idx >= 0);
1870
1871                 if (!ds) {
1872                         ret = -EINVAL;
1873                         break;
1874                 }
1875
1876                 ep->ep->driver_data = ep;
1877                 ep->ep->desc = ds;
1878
1879                 if (needs_comp_desc) {
1880                         comp_desc = (struct usb_ss_ep_comp_descriptor *)(ds +
1881                                         USB_DT_ENDPOINT_SIZE);
1882                         ep->ep->maxburst = comp_desc->bMaxBurst + 1;
1883                         ep->ep->comp_desc = comp_desc;
1884                 }
1885
1886                 ret = usb_ep_enable(ep->ep);
1887                 if (likely(!ret)) {
1888                         epfile->ep = ep;
1889                         epfile->in = usb_endpoint_dir_in(ds);
1890                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1891                 } else {
1892                         break;
1893                 }
1894
1895                 wake_up(&epfile->wait);
1896
1897                 ++ep;
1898                 ++epfile;
1899         } while (--count);
1900         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1901
1902         return ret;
1903 }
1904
1905
1906 /* Parsing and building descriptors and strings *****************************/
1907
1908 /*
1909  * This validates if data pointed by data is a valid USB descriptor as
1910  * well as record how many interfaces, endpoints and strings are
1911  * required by given configuration.  Returns address after the
1912  * descriptor or NULL if data is invalid.
1913  */
1914
1915 enum ffs_entity_type {
1916         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1917 };
1918
1919 enum ffs_os_desc_type {
1920         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1921 };
1922
1923 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1924                                    u8 *valuep,
1925                                    struct usb_descriptor_header *desc,
1926                                    void *priv);
1927
1928 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1929                                     struct usb_os_desc_header *h, void *data,
1930                                     unsigned len, void *priv);
1931
1932 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1933                                            ffs_entity_callback entity,
1934                                            void *priv)
1935 {
1936         struct usb_descriptor_header *_ds = (void *)data;
1937         u8 length;
1938         int ret;
1939
1940         ENTER();
1941
1942         /* At least two bytes are required: length and type */
1943         if (len < 2) {
1944                 pr_vdebug("descriptor too short\n");
1945                 return -EINVAL;
1946         }
1947
1948         /* If we have at least as many bytes as the descriptor takes? */
1949         length = _ds->bLength;
1950         if (len < length) {
1951                 pr_vdebug("descriptor longer then available data\n");
1952                 return -EINVAL;
1953         }
1954
1955 #define __entity_check_INTERFACE(val)  1
1956 #define __entity_check_STRING(val)     (val)
1957 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1958 #define __entity(type, val) do {                                        \
1959                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1960                 if (unlikely(!__entity_check_ ##type(val))) {           \
1961                         pr_vdebug("invalid entity's value\n");          \
1962                         return -EINVAL;                                 \
1963                 }                                                       \
1964                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1965                 if (unlikely(ret < 0)) {                                \
1966                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1967                                  (val), ret);                           \
1968                         return ret;                                     \
1969                 }                                                       \
1970         } while (0)
1971
1972         /* Parse descriptor depending on type. */
1973         switch (_ds->bDescriptorType) {
1974         case USB_DT_DEVICE:
1975         case USB_DT_CONFIG:
1976         case USB_DT_STRING:
1977         case USB_DT_DEVICE_QUALIFIER:
1978                 /* function can't have any of those */
1979                 pr_vdebug("descriptor reserved for gadget: %d\n",
1980                       _ds->bDescriptorType);
1981                 return -EINVAL;
1982
1983         case USB_DT_INTERFACE: {
1984                 struct usb_interface_descriptor *ds = (void *)_ds;
1985                 pr_vdebug("interface descriptor\n");
1986                 if (length != sizeof *ds)
1987                         goto inv_length;
1988
1989                 __entity(INTERFACE, ds->bInterfaceNumber);
1990                 if (ds->iInterface)
1991                         __entity(STRING, ds->iInterface);
1992         }
1993                 break;
1994
1995         case USB_DT_ENDPOINT: {
1996                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1997                 pr_vdebug("endpoint descriptor\n");
1998                 if (length != USB_DT_ENDPOINT_SIZE &&
1999                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2000                         goto inv_length;
2001                 __entity(ENDPOINT, ds->bEndpointAddress);
2002         }
2003                 break;
2004
2005         case HID_DT_HID:
2006                 pr_vdebug("hid descriptor\n");
2007                 if (length != sizeof(struct hid_descriptor))
2008                         goto inv_length;
2009                 break;
2010
2011         case USB_DT_OTG:
2012                 if (length != sizeof(struct usb_otg_descriptor))
2013                         goto inv_length;
2014                 break;
2015
2016         case USB_DT_INTERFACE_ASSOCIATION: {
2017                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2018                 pr_vdebug("interface association descriptor\n");
2019                 if (length != sizeof *ds)
2020                         goto inv_length;
2021                 if (ds->iFunction)
2022                         __entity(STRING, ds->iFunction);
2023         }
2024                 break;
2025
2026         case USB_DT_SS_ENDPOINT_COMP:
2027                 pr_vdebug("EP SS companion descriptor\n");
2028                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2029                         goto inv_length;
2030                 break;
2031
2032         case USB_DT_OTHER_SPEED_CONFIG:
2033         case USB_DT_INTERFACE_POWER:
2034         case USB_DT_DEBUG:
2035         case USB_DT_SECURITY:
2036         case USB_DT_CS_RADIO_CONTROL:
2037                 /* TODO */
2038                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2039                 return -EINVAL;
2040
2041         default:
2042                 /* We should never be here */
2043                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2044                 return -EINVAL;
2045
2046 inv_length:
2047                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2048                           _ds->bLength, _ds->bDescriptorType);
2049                 return -EINVAL;
2050         }
2051
2052 #undef __entity
2053 #undef __entity_check_DESCRIPTOR
2054 #undef __entity_check_INTERFACE
2055 #undef __entity_check_STRING
2056 #undef __entity_check_ENDPOINT
2057
2058         return length;
2059 }
2060
2061 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2062                                      ffs_entity_callback entity, void *priv)
2063 {
2064         const unsigned _len = len;
2065         unsigned long num = 0;
2066
2067         ENTER();
2068
2069         for (;;) {
2070                 int ret;
2071
2072                 if (num == count)
2073                         data = NULL;
2074
2075                 /* Record "descriptor" entity */
2076                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2077                 if (unlikely(ret < 0)) {
2078                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2079                                  num, ret);
2080                         return ret;
2081                 }
2082
2083                 if (!data)
2084                         return _len - len;
2085
2086                 ret = ffs_do_single_desc(data, len, entity, priv);
2087                 if (unlikely(ret < 0)) {
2088                         pr_debug("%s returns %d\n", __func__, ret);
2089                         return ret;
2090                 }
2091
2092                 len -= ret;
2093                 data += ret;
2094                 ++num;
2095         }
2096 }
2097
2098 static int __ffs_data_do_entity(enum ffs_entity_type type,
2099                                 u8 *valuep, struct usb_descriptor_header *desc,
2100                                 void *priv)
2101 {
2102         struct ffs_desc_helper *helper = priv;
2103         struct usb_endpoint_descriptor *d;
2104
2105         ENTER();
2106
2107         switch (type) {
2108         case FFS_DESCRIPTOR:
2109                 break;
2110
2111         case FFS_INTERFACE:
2112                 /*
2113                  * Interfaces are indexed from zero so if we
2114                  * encountered interface "n" then there are at least
2115                  * "n+1" interfaces.
2116                  */
2117                 if (*valuep >= helper->interfaces_count)
2118                         helper->interfaces_count = *valuep + 1;
2119                 break;
2120
2121         case FFS_STRING:
2122                 /*
2123                  * Strings are indexed from 1 (0 is magic ;) reserved
2124                  * for languages list or some such)
2125                  */
2126                 if (*valuep > helper->ffs->strings_count)
2127                         helper->ffs->strings_count = *valuep;
2128                 break;
2129
2130         case FFS_ENDPOINT:
2131                 d = (void *)desc;
2132                 helper->eps_count++;
2133                 if (helper->eps_count >= 15)
2134                         return -EINVAL;
2135                 /* Check if descriptors for any speed were already parsed */
2136                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2137                         helper->ffs->eps_addrmap[helper->eps_count] =
2138                                 d->bEndpointAddress;
2139                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2140                                 d->bEndpointAddress)
2141                         return -EINVAL;
2142                 break;
2143         }
2144
2145         return 0;
2146 }
2147
2148 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2149                                    struct usb_os_desc_header *desc)
2150 {
2151         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2152         u16 w_index = le16_to_cpu(desc->wIndex);
2153
2154         if (bcd_version != 1) {
2155                 pr_vdebug("unsupported os descriptors version: %d",
2156                           bcd_version);
2157                 return -EINVAL;
2158         }
2159         switch (w_index) {
2160         case 0x4:
2161                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2162                 break;
2163         case 0x5:
2164                 *next_type = FFS_OS_DESC_EXT_PROP;
2165                 break;
2166         default:
2167                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2168                 return -EINVAL;
2169         }
2170
2171         return sizeof(*desc);
2172 }
2173
2174 /*
2175  * Process all extended compatibility/extended property descriptors
2176  * of a feature descriptor
2177  */
2178 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2179                                               enum ffs_os_desc_type type,
2180                                               u16 feature_count,
2181                                               ffs_os_desc_callback entity,
2182                                               void *priv,
2183                                               struct usb_os_desc_header *h)
2184 {
2185         int ret;
2186         const unsigned _len = len;
2187
2188         ENTER();
2189
2190         /* loop over all ext compat/ext prop descriptors */
2191         while (feature_count--) {
2192                 ret = entity(type, h, data, len, priv);
2193                 if (unlikely(ret < 0)) {
2194                         pr_debug("bad OS descriptor, type: %d\n", type);
2195                         return ret;
2196                 }
2197                 data += ret;
2198                 len -= ret;
2199         }
2200         return _len - len;
2201 }
2202
2203 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2204 static int __must_check ffs_do_os_descs(unsigned count,
2205                                         char *data, unsigned len,
2206                                         ffs_os_desc_callback entity, void *priv)
2207 {
2208         const unsigned _len = len;
2209         unsigned long num = 0;
2210
2211         ENTER();
2212
2213         for (num = 0; num < count; ++num) {
2214                 int ret;
2215                 enum ffs_os_desc_type type;
2216                 u16 feature_count;
2217                 struct usb_os_desc_header *desc = (void *)data;
2218
2219                 if (len < sizeof(*desc))
2220                         return -EINVAL;
2221
2222                 /*
2223                  * Record "descriptor" entity.
2224                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2225                  * Move the data pointer to the beginning of extended
2226                  * compatibilities proper or extended properties proper
2227                  * portions of the data
2228                  */
2229                 if (le32_to_cpu(desc->dwLength) > len)
2230                         return -EINVAL;
2231
2232                 ret = __ffs_do_os_desc_header(&type, desc);
2233                 if (unlikely(ret < 0)) {
2234                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2235                                  num, ret);
2236                         return ret;
2237                 }
2238                 /*
2239                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2240                  */
2241                 feature_count = le16_to_cpu(desc->wCount);
2242                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2243                     (feature_count > 255 || desc->Reserved))
2244                                 return -EINVAL;
2245                 len -= ret;
2246                 data += ret;
2247
2248                 /*
2249                  * Process all function/property descriptors
2250                  * of this Feature Descriptor
2251                  */
2252                 ret = ffs_do_single_os_desc(data, len, type,
2253                                             feature_count, entity, priv, desc);
2254                 if (unlikely(ret < 0)) {
2255                         pr_debug("%s returns %d\n", __func__, ret);
2256                         return ret;
2257                 }
2258
2259                 len -= ret;
2260                 data += ret;
2261         }
2262         return _len - len;
2263 }
2264
2265 /**
2266  * Validate contents of the buffer from userspace related to OS descriptors.
2267  */
2268 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2269                                  struct usb_os_desc_header *h, void *data,
2270                                  unsigned len, void *priv)
2271 {
2272         struct ffs_data *ffs = priv;
2273         u8 length;
2274
2275         ENTER();
2276
2277         switch (type) {
2278         case FFS_OS_DESC_EXT_COMPAT: {
2279                 struct usb_ext_compat_desc *d = data;
2280                 int i;
2281
2282                 if (len < sizeof(*d) ||
2283                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2284                         return -EINVAL;
2285                 if (d->Reserved1 != 1) {
2286                         /*
2287                          * According to the spec, Reserved1 must be set to 1
2288                          * but older kernels incorrectly rejected non-zero
2289                          * values.  We fix it here to avoid returning EINVAL
2290                          * in response to values we used to accept.
2291                          */
2292                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2293                         d->Reserved1 = 1;
2294                 }
2295                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2296                         if (d->Reserved2[i])
2297                                 return -EINVAL;
2298
2299                 length = sizeof(struct usb_ext_compat_desc);
2300         }
2301                 break;
2302         case FFS_OS_DESC_EXT_PROP: {
2303                 struct usb_ext_prop_desc *d = data;
2304                 u32 type, pdl;
2305                 u16 pnl;
2306
2307                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2308                         return -EINVAL;
2309                 length = le32_to_cpu(d->dwSize);
2310                 if (len < length)
2311                         return -EINVAL;
2312                 type = le32_to_cpu(d->dwPropertyDataType);
2313                 if (type < USB_EXT_PROP_UNICODE ||
2314                     type > USB_EXT_PROP_UNICODE_MULTI) {
2315                         pr_vdebug("unsupported os descriptor property type: %d",
2316                                   type);
2317                         return -EINVAL;
2318                 }
2319                 pnl = le16_to_cpu(d->wPropertyNameLength);
2320                 if (length < 14 + pnl) {
2321                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2322                                   length, pnl, type);
2323                         return -EINVAL;
2324                 }
2325                 pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
2326                 if (length != 14 + pnl + pdl) {
2327                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2328                                   length, pnl, pdl, type);
2329                         return -EINVAL;
2330                 }
2331                 ++ffs->ms_os_descs_ext_prop_count;
2332                 /* property name reported to the host as "WCHAR"s */
2333                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2334                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2335         }
2336                 break;
2337         default:
2338                 pr_vdebug("unknown descriptor: %d\n", type);
2339                 return -EINVAL;
2340         }
2341         return length;
2342 }
2343
2344 static int __ffs_data_got_descs(struct ffs_data *ffs,
2345                                 char *const _data, size_t len)
2346 {
2347         char *data = _data, *raw_descs;
2348         unsigned os_descs_count = 0, counts[3], flags;
2349         int ret = -EINVAL, i;
2350         struct ffs_desc_helper helper;
2351
2352         ENTER();
2353
2354         if (get_unaligned_le32(data + 4) != len)
2355                 goto error;
2356
2357         switch (get_unaligned_le32(data)) {
2358         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2359                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2360                 data += 8;
2361                 len  -= 8;
2362                 break;
2363         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2364                 flags = get_unaligned_le32(data + 8);
2365                 ffs->user_flags = flags;
2366                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2367                               FUNCTIONFS_HAS_HS_DESC |
2368                               FUNCTIONFS_HAS_SS_DESC |
2369                               FUNCTIONFS_HAS_MS_OS_DESC |
2370                               FUNCTIONFS_VIRTUAL_ADDR |
2371                               FUNCTIONFS_EVENTFD |
2372                               FUNCTIONFS_ALL_CTRL_RECIP |
2373                               FUNCTIONFS_CONFIG0_SETUP)) {
2374                         ret = -ENOSYS;
2375                         goto error;
2376                 }
2377                 data += 12;
2378                 len  -= 12;
2379                 break;
2380         default:
2381                 goto error;
2382         }
2383
2384         if (flags & FUNCTIONFS_EVENTFD) {
2385                 if (len < 4)
2386                         goto error;
2387                 ffs->ffs_eventfd =
2388                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2389                 if (IS_ERR(ffs->ffs_eventfd)) {
2390                         ret = PTR_ERR(ffs->ffs_eventfd);
2391                         ffs->ffs_eventfd = NULL;
2392                         goto error;
2393                 }
2394                 data += 4;
2395                 len  -= 4;
2396         }
2397
2398         /* Read fs_count, hs_count and ss_count (if present) */
2399         for (i = 0; i < 3; ++i) {
2400                 if (!(flags & (1 << i))) {
2401                         counts[i] = 0;
2402                 } else if (len < 4) {
2403                         goto error;
2404                 } else {
2405                         counts[i] = get_unaligned_le32(data);
2406                         data += 4;
2407                         len  -= 4;
2408                 }
2409         }
2410         if (flags & (1 << i)) {
2411                 if (len < 4) {
2412                         goto error;
2413                 }
2414                 os_descs_count = get_unaligned_le32(data);
2415                 data += 4;
2416                 len -= 4;
2417         };
2418
2419         /* Read descriptors */
2420         raw_descs = data;
2421         helper.ffs = ffs;
2422         for (i = 0; i < 3; ++i) {
2423                 if (!counts[i])
2424                         continue;
2425                 helper.interfaces_count = 0;
2426                 helper.eps_count = 0;
2427                 ret = ffs_do_descs(counts[i], data, len,
2428                                    __ffs_data_do_entity, &helper);
2429                 if (ret < 0)
2430                         goto error;
2431                 if (!ffs->eps_count && !ffs->interfaces_count) {
2432                         ffs->eps_count = helper.eps_count;
2433                         ffs->interfaces_count = helper.interfaces_count;
2434                 } else {
2435                         if (ffs->eps_count != helper.eps_count) {
2436                                 ret = -EINVAL;
2437                                 goto error;
2438                         }
2439                         if (ffs->interfaces_count != helper.interfaces_count) {
2440                                 ret = -EINVAL;
2441                                 goto error;
2442                         }
2443                 }
2444                 data += ret;
2445                 len  -= ret;
2446         }
2447         if (os_descs_count) {
2448                 ret = ffs_do_os_descs(os_descs_count, data, len,
2449                                       __ffs_data_do_os_desc, ffs);
2450                 if (ret < 0)
2451                         goto error;
2452                 data += ret;
2453                 len -= ret;
2454         }
2455
2456         if (raw_descs == data || len) {
2457                 ret = -EINVAL;
2458                 goto error;
2459         }
2460
2461         ffs->raw_descs_data     = _data;
2462         ffs->raw_descs          = raw_descs;
2463         ffs->raw_descs_length   = data - raw_descs;
2464         ffs->fs_descs_count     = counts[0];
2465         ffs->hs_descs_count     = counts[1];
2466         ffs->ss_descs_count     = counts[2];
2467         ffs->ms_os_descs_count  = os_descs_count;
2468
2469         return 0;
2470
2471 error:
2472         kfree(_data);
2473         return ret;
2474 }
2475
2476 static int __ffs_data_got_strings(struct ffs_data *ffs,
2477                                   char *const _data, size_t len)
2478 {
2479         u32 str_count, needed_count, lang_count;
2480         struct usb_gadget_strings **stringtabs, *t;
2481         const char *data = _data;
2482         struct usb_string *s;
2483
2484         ENTER();
2485
2486         if (unlikely(len < 16 ||
2487                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2488                      get_unaligned_le32(data + 4) != len))
2489                 goto error;
2490         str_count  = get_unaligned_le32(data + 8);
2491         lang_count = get_unaligned_le32(data + 12);
2492
2493         /* if one is zero the other must be zero */
2494         if (unlikely(!str_count != !lang_count))
2495                 goto error;
2496
2497         /* Do we have at least as many strings as descriptors need? */
2498         needed_count = ffs->strings_count;
2499         if (unlikely(str_count < needed_count))
2500                 goto error;
2501
2502         /*
2503          * If we don't need any strings just return and free all
2504          * memory.
2505          */
2506         if (!needed_count) {
2507                 kfree(_data);
2508                 return 0;
2509         }
2510
2511         /* Allocate everything in one chunk so there's less maintenance. */
2512         {
2513                 unsigned i = 0;
2514                 vla_group(d);
2515                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2516                         lang_count + 1);
2517                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2518                 vla_item(d, struct usb_string, strings,
2519                         lang_count*(needed_count+1));
2520
2521                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2522
2523                 if (unlikely(!vlabuf)) {
2524                         kfree(_data);
2525                         return -ENOMEM;
2526                 }
2527
2528                 /* Initialize the VLA pointers */
2529                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2530                 t = vla_ptr(vlabuf, d, stringtab);
2531                 i = lang_count;
2532                 do {
2533                         *stringtabs++ = t++;
2534                 } while (--i);
2535                 *stringtabs = NULL;
2536
2537                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2538                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2539                 t = vla_ptr(vlabuf, d, stringtab);
2540                 s = vla_ptr(vlabuf, d, strings);
2541         }
2542
2543         /* For each language */
2544         data += 16;
2545         len -= 16;
2546
2547         do { /* lang_count > 0 so we can use do-while */
2548                 unsigned needed = needed_count;
2549                 u32 str_per_lang = str_count;
2550
2551                 if (unlikely(len < 3))
2552                         goto error_free;
2553                 t->language = get_unaligned_le16(data);
2554                 t->strings  = s;
2555                 ++t;
2556
2557                 data += 2;
2558                 len -= 2;
2559
2560                 /* For each string */
2561                 do { /* str_count > 0 so we can use do-while */
2562                         size_t length = strnlen(data, len);
2563
2564                         if (unlikely(length == len))
2565                                 goto error_free;
2566
2567                         /*
2568                          * User may provide more strings then we need,
2569                          * if that's the case we simply ignore the
2570                          * rest
2571                          */
2572                         if (likely(needed)) {
2573                                 /*
2574                                  * s->id will be set while adding
2575                                  * function to configuration so for
2576                                  * now just leave garbage here.
2577                                  */
2578                                 s->s = data;
2579                                 --needed;
2580                                 ++s;
2581                         }
2582
2583                         data += length + 1;
2584                         len -= length + 1;
2585                 } while (--str_per_lang);
2586
2587                 s->id = 0;   /* terminator */
2588                 s->s = NULL;
2589                 ++s;
2590
2591         } while (--lang_count);
2592
2593         /* Some garbage left? */
2594         if (unlikely(len))
2595                 goto error_free;
2596
2597         /* Done! */
2598         ffs->stringtabs = stringtabs;
2599         ffs->raw_strings = _data;
2600
2601         return 0;
2602
2603 error_free:
2604         kfree(stringtabs);
2605 error:
2606         kfree(_data);
2607         return -EINVAL;
2608 }
2609
2610
2611 /* Events handling and management *******************************************/
2612
2613 static void __ffs_event_add(struct ffs_data *ffs,
2614                             enum usb_functionfs_event_type type)
2615 {
2616         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2617         int neg = 0;
2618
2619         /*
2620          * Abort any unhandled setup
2621          *
2622          * We do not need to worry about some cmpxchg() changing value
2623          * of ffs->setup_state without holding the lock because when
2624          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2625          * the source does nothing.
2626          */
2627         if (ffs->setup_state == FFS_SETUP_PENDING)
2628                 ffs->setup_state = FFS_SETUP_CANCELLED;
2629
2630         /*
2631          * Logic of this function guarantees that there are at most four pending
2632          * evens on ffs->ev.types queue.  This is important because the queue
2633          * has space for four elements only and __ffs_ep0_read_events function
2634          * depends on that limit as well.  If more event types are added, those
2635          * limits have to be revisited or guaranteed to still hold.
2636          */
2637         switch (type) {
2638         case FUNCTIONFS_RESUME:
2639                 rem_type2 = FUNCTIONFS_SUSPEND;
2640                 /* FALL THROUGH */
2641         case FUNCTIONFS_SUSPEND:
2642         case FUNCTIONFS_SETUP:
2643                 rem_type1 = type;
2644                 /* Discard all similar events */
2645                 break;
2646
2647         case FUNCTIONFS_BIND:
2648         case FUNCTIONFS_UNBIND:
2649         case FUNCTIONFS_DISABLE:
2650         case FUNCTIONFS_ENABLE:
2651                 /* Discard everything other then power management. */
2652                 rem_type1 = FUNCTIONFS_SUSPEND;
2653                 rem_type2 = FUNCTIONFS_RESUME;
2654                 neg = 1;
2655                 break;
2656
2657         default:
2658                 WARN(1, "%d: unknown event, this should not happen\n", type);
2659                 return;
2660         }
2661
2662         {
2663                 u8 *ev  = ffs->ev.types, *out = ev;
2664                 unsigned n = ffs->ev.count;
2665                 for (; n; --n, ++ev)
2666                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2667                                 *out++ = *ev;
2668                         else
2669                                 pr_vdebug("purging event %d\n", *ev);
2670                 ffs->ev.count = out - ffs->ev.types;
2671         }
2672
2673         pr_vdebug("adding event %d\n", type);
2674         ffs->ev.types[ffs->ev.count++] = type;
2675         wake_up_locked(&ffs->ev.waitq);
2676         if (ffs->ffs_eventfd)
2677                 eventfd_signal(ffs->ffs_eventfd, 1);
2678 }
2679
2680 static void ffs_event_add(struct ffs_data *ffs,
2681                           enum usb_functionfs_event_type type)
2682 {
2683         unsigned long flags;
2684         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2685         __ffs_event_add(ffs, type);
2686         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2687 }
2688
2689 /* Bind/unbind USB function hooks *******************************************/
2690
2691 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2692 {
2693         int i;
2694
2695         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2696                 if (ffs->eps_addrmap[i] == endpoint_address)
2697                         return i;
2698         return -ENOENT;
2699 }
2700
2701 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2702                                     struct usb_descriptor_header *desc,
2703                                     void *priv)
2704 {
2705         struct usb_endpoint_descriptor *ds = (void *)desc;
2706         struct ffs_function *func = priv;
2707         struct ffs_ep *ffs_ep;
2708         unsigned ep_desc_id;
2709         int idx;
2710         static const char *speed_names[] = { "full", "high", "super" };
2711
2712         if (type != FFS_DESCRIPTOR)
2713                 return 0;
2714
2715         /*
2716          * If ss_descriptors is not NULL, we are reading super speed
2717          * descriptors; if hs_descriptors is not NULL, we are reading high
2718          * speed descriptors; otherwise, we are reading full speed
2719          * descriptors.
2720          */
2721         if (func->function.ss_descriptors) {
2722                 ep_desc_id = 2;
2723                 func->function.ss_descriptors[(long)valuep] = desc;
2724         } else if (func->function.hs_descriptors) {
2725                 ep_desc_id = 1;
2726                 func->function.hs_descriptors[(long)valuep] = desc;
2727         } else {
2728                 ep_desc_id = 0;
2729                 func->function.fs_descriptors[(long)valuep]    = desc;
2730         }
2731
2732         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2733                 return 0;
2734
2735         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2736         if (idx < 0)
2737                 return idx;
2738
2739         ffs_ep = func->eps + idx;
2740
2741         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2742                 pr_err("two %sspeed descriptors for EP %d\n",
2743                           speed_names[ep_desc_id],
2744                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2745                 return -EINVAL;
2746         }
2747         ffs_ep->descs[ep_desc_id] = ds;
2748
2749         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2750         if (ffs_ep->ep) {
2751                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2752                 if (!ds->wMaxPacketSize)
2753                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2754         } else {
2755                 struct usb_request *req;
2756                 struct usb_ep *ep;
2757                 u8 bEndpointAddress;
2758
2759                 /*
2760                  * We back up bEndpointAddress because autoconfig overwrites
2761                  * it with physical endpoint address.
2762                  */
2763                 bEndpointAddress = ds->bEndpointAddress;
2764                 pr_vdebug("autoconfig\n");
2765                 ep = usb_ep_autoconfig(func->gadget, ds);
2766                 if (unlikely(!ep))
2767                         return -ENOTSUPP;
2768                 ep->driver_data = func->eps + idx;
2769
2770                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2771                 if (unlikely(!req))
2772                         return -ENOMEM;
2773
2774                 ffs_ep->ep  = ep;
2775                 ffs_ep->req = req;
2776                 func->eps_revmap[ds->bEndpointAddress &
2777                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2778                 /*
2779                  * If we use virtual address mapping, we restore
2780                  * original bEndpointAddress value.
2781                  */
2782                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2783                         ds->bEndpointAddress = bEndpointAddress;
2784         }
2785         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2786
2787         return 0;
2788 }
2789
2790 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2791                                    struct usb_descriptor_header *desc,
2792                                    void *priv)
2793 {
2794         struct ffs_function *func = priv;
2795         unsigned idx;
2796         u8 newValue;
2797
2798         switch (type) {
2799         default:
2800         case FFS_DESCRIPTOR:
2801                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2802                 return 0;
2803
2804         case FFS_INTERFACE:
2805                 idx = *valuep;
2806                 if (func->interfaces_nums[idx] < 0) {
2807                         int id = usb_interface_id(func->conf, &func->function);
2808                         if (unlikely(id < 0))
2809                                 return id;
2810                         func->interfaces_nums[idx] = id;
2811                 }
2812                 newValue = func->interfaces_nums[idx];
2813                 break;
2814
2815         case FFS_STRING:
2816                 /* String' IDs are allocated when fsf_data is bound to cdev */
2817                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2818                 break;
2819
2820         case FFS_ENDPOINT:
2821                 /*
2822                  * USB_DT_ENDPOINT are handled in
2823                  * __ffs_func_bind_do_descs().
2824                  */
2825                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2826                         return 0;
2827
2828                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2829                 if (unlikely(!func->eps[idx].ep))
2830                         return -EINVAL;
2831
2832                 {
2833                         struct usb_endpoint_descriptor **descs;
2834                         descs = func->eps[idx].descs;
2835                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2836                 }
2837                 break;
2838         }
2839
2840         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2841         *valuep = newValue;
2842         return 0;
2843 }
2844
2845 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2846                                       struct usb_os_desc_header *h, void *data,
2847                                       unsigned len, void *priv)
2848 {
2849         struct ffs_function *func = priv;
2850         u8 length = 0;
2851
2852         switch (type) {
2853         case FFS_OS_DESC_EXT_COMPAT: {
2854                 struct usb_ext_compat_desc *desc = data;
2855                 struct usb_os_desc_table *t;
2856
2857                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2858                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2859                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2860                        ARRAY_SIZE(desc->CompatibleID) +
2861                        ARRAY_SIZE(desc->SubCompatibleID));
2862                 length = sizeof(*desc);
2863         }
2864                 break;
2865         case FFS_OS_DESC_EXT_PROP: {
2866                 struct usb_ext_prop_desc *desc = data;
2867                 struct usb_os_desc_table *t;
2868                 struct usb_os_desc_ext_prop *ext_prop;
2869                 char *ext_prop_name;
2870                 char *ext_prop_data;
2871
2872                 t = &func->function.os_desc_table[h->interface];
2873                 t->if_id = func->interfaces_nums[h->interface];
2874
2875                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2876                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2877
2878                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2879                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2880                 ext_prop->data_len = le32_to_cpu(*(u32 *)
2881                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2882                 length = ext_prop->name_len + ext_prop->data_len + 14;
2883
2884                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2885                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2886                         ext_prop->name_len;
2887
2888                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2889                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2890                         ext_prop->data_len;
2891                 memcpy(ext_prop_data,
2892                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2893                        ext_prop->data_len);
2894                 /* unicode data reported to the host as "WCHAR"s */
2895                 switch (ext_prop->type) {
2896                 case USB_EXT_PROP_UNICODE:
2897                 case USB_EXT_PROP_UNICODE_ENV:
2898                 case USB_EXT_PROP_UNICODE_LINK:
2899                 case USB_EXT_PROP_UNICODE_MULTI:
2900                         ext_prop->data_len *= 2;
2901                         break;
2902                 }
2903                 ext_prop->data = ext_prop_data;
2904
2905                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2906                        ext_prop->name_len);
2907                 /* property name reported to the host as "WCHAR"s */
2908                 ext_prop->name_len *= 2;
2909                 ext_prop->name = ext_prop_name;
2910
2911                 t->os_desc->ext_prop_len +=
2912                         ext_prop->name_len + ext_prop->data_len + 14;
2913                 ++t->os_desc->ext_prop_count;
2914                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2915         }
2916                 break;
2917         default:
2918                 pr_vdebug("unknown descriptor: %d\n", type);
2919         }
2920
2921         return length;
2922 }
2923
2924 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2925                                                 struct usb_configuration *c)
2926 {
2927         struct ffs_function *func = ffs_func_from_usb(f);
2928         struct f_fs_opts *ffs_opts =
2929                 container_of(f->fi, struct f_fs_opts, func_inst);
2930         int ret;
2931
2932         ENTER();
2933
2934         /*
2935          * Legacy gadget triggers binding in functionfs_ready_callback,
2936          * which already uses locking; taking the same lock here would
2937          * cause a deadlock.
2938          *
2939          * Configfs-enabled gadgets however do need ffs_dev_lock.
2940          */
2941         if (!ffs_opts->no_configfs)
2942                 ffs_dev_lock();
2943         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2944         func->ffs = ffs_opts->dev->ffs_data;
2945         if (!ffs_opts->no_configfs)
2946                 ffs_dev_unlock();
2947         if (ret)
2948                 return ERR_PTR(ret);
2949
2950         func->conf = c;
2951         func->gadget = c->cdev->gadget;
2952
2953         /*
2954          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2955          * configurations are bound in sequence with list_for_each_entry,
2956          * in each configuration its functions are bound in sequence
2957          * with list_for_each_entry, so we assume no race condition
2958          * with regard to ffs_opts->bound access
2959          */
2960         if (!ffs_opts->refcnt) {
2961                 ret = functionfs_bind(func->ffs, c->cdev);
2962                 if (ret)
2963                         return ERR_PTR(ret);
2964         }
2965         ffs_opts->refcnt++;
2966         func->function.strings = func->ffs->stringtabs;
2967
2968         return ffs_opts;
2969 }
2970
2971 static int _ffs_func_bind(struct usb_configuration *c,
2972                           struct usb_function *f)
2973 {
2974         struct ffs_function *func = ffs_func_from_usb(f);
2975         struct ffs_data *ffs = func->ffs;
2976
2977         const int full = !!func->ffs->fs_descs_count;
2978         const int high = !!func->ffs->hs_descs_count;
2979         const int super = !!func->ffs->ss_descs_count;
2980
2981         int fs_len, hs_len, ss_len, ret, i;
2982         struct ffs_ep *eps_ptr;
2983
2984         /* Make it a single chunk, less management later on */
2985         vla_group(d);
2986         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2987         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2988                 full ? ffs->fs_descs_count + 1 : 0);
2989         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2990                 high ? ffs->hs_descs_count + 1 : 0);
2991         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2992                 super ? ffs->ss_descs_count + 1 : 0);
2993         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2994         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2995                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2996         vla_item_with_sz(d, char[16], ext_compat,
2997                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2998         vla_item_with_sz(d, struct usb_os_desc, os_desc,
2999                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3000         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3001                          ffs->ms_os_descs_ext_prop_count);
3002         vla_item_with_sz(d, char, ext_prop_name,
3003                          ffs->ms_os_descs_ext_prop_name_len);
3004         vla_item_with_sz(d, char, ext_prop_data,
3005                          ffs->ms_os_descs_ext_prop_data_len);
3006         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3007         char *vlabuf;
3008
3009         ENTER();
3010
3011         /* Has descriptors only for speeds gadget does not support */
3012         if (unlikely(!(full | high | super)))
3013                 return -ENOTSUPP;
3014
3015         /* Allocate a single chunk, less management later on */
3016         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3017         if (unlikely(!vlabuf))
3018                 return -ENOMEM;
3019
3020         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3021         ffs->ms_os_descs_ext_prop_name_avail =
3022                 vla_ptr(vlabuf, d, ext_prop_name);
3023         ffs->ms_os_descs_ext_prop_data_avail =
3024                 vla_ptr(vlabuf, d, ext_prop_data);
3025
3026         /* Copy descriptors  */
3027         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3028                ffs->raw_descs_length);
3029
3030         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3031         eps_ptr = vla_ptr(vlabuf, d, eps);
3032         for (i = 0; i < ffs->eps_count; i++)
3033                 eps_ptr[i].num = -1;
3034
3035         /* Save pointers
3036          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3037         */
3038         func->eps             = vla_ptr(vlabuf, d, eps);
3039         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3040
3041         /*
3042          * Go through all the endpoint descriptors and allocate
3043          * endpoints first, so that later we can rewrite the endpoint
3044          * numbers without worrying that it may be described later on.
3045          */
3046         if (likely(full)) {
3047                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3048                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3049                                       vla_ptr(vlabuf, d, raw_descs),
3050                                       d_raw_descs__sz,
3051                                       __ffs_func_bind_do_descs, func);
3052                 if (unlikely(fs_len < 0)) {
3053                         ret = fs_len;
3054                         goto error;
3055                 }
3056         } else {
3057                 fs_len = 0;
3058         }
3059
3060         if (likely(high)) {
3061                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3062                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3063                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3064                                       d_raw_descs__sz - fs_len,
3065                                       __ffs_func_bind_do_descs, func);
3066                 if (unlikely(hs_len < 0)) {
3067                         ret = hs_len;
3068                         goto error;
3069                 }
3070         } else {
3071                 hs_len = 0;
3072         }
3073
3074         if (likely(super)) {
3075                 func->function.ss_descriptors = func->function.ssp_descriptors =
3076                         vla_ptr(vlabuf, d, ss_descs);
3077                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3078                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3079                                 d_raw_descs__sz - fs_len - hs_len,
3080                                 __ffs_func_bind_do_descs, func);
3081                 if (unlikely(ss_len < 0)) {
3082                         ret = ss_len;
3083                         goto error;
3084                 }
3085         } else {
3086                 ss_len = 0;
3087         }
3088
3089         /*
3090          * Now handle interface numbers allocation and interface and
3091          * endpoint numbers rewriting.  We can do that in one go
3092          * now.
3093          */
3094         ret = ffs_do_descs(ffs->fs_descs_count +
3095                            (high ? ffs->hs_descs_count : 0) +
3096                            (super ? ffs->ss_descs_count : 0),
3097                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3098                            __ffs_func_bind_do_nums, func);
3099         if (unlikely(ret < 0))
3100                 goto error;
3101
3102         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3103         if (c->cdev->use_os_string) {
3104                 for (i = 0; i < ffs->interfaces_count; ++i) {
3105                         struct usb_os_desc *desc;
3106
3107                         desc = func->function.os_desc_table[i].os_desc =
3108                                 vla_ptr(vlabuf, d, os_desc) +
3109                                 i * sizeof(struct usb_os_desc);
3110                         desc->ext_compat_id =
3111                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3112                         INIT_LIST_HEAD(&desc->ext_prop);
3113                 }
3114                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3115                                       vla_ptr(vlabuf, d, raw_descs) +
3116                                       fs_len + hs_len + ss_len,
3117                                       d_raw_descs__sz - fs_len - hs_len -
3118                                       ss_len,
3119                                       __ffs_func_bind_do_os_desc, func);
3120                 if (unlikely(ret < 0))
3121                         goto error;
3122         }
3123         func->function.os_desc_n =
3124                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3125
3126         /* And we're done */
3127         ffs_event_add(ffs, FUNCTIONFS_BIND);
3128         return 0;
3129
3130 error:
3131         /* XXX Do we need to release all claimed endpoints here? */
3132         return ret;
3133 }
3134
3135 static int ffs_func_bind(struct usb_configuration *c,
3136                          struct usb_function *f)
3137 {
3138         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3139         struct ffs_function *func = ffs_func_from_usb(f);
3140         int ret;
3141
3142         if (IS_ERR(ffs_opts))
3143                 return PTR_ERR(ffs_opts);
3144
3145         ret = _ffs_func_bind(c, f);
3146         if (ret && !--ffs_opts->refcnt)
3147                 functionfs_unbind(func->ffs);
3148
3149         return ret;
3150 }
3151
3152
3153 /* Other USB function hooks *************************************************/
3154
3155 static void ffs_reset_work(struct work_struct *work)
3156 {
3157         struct ffs_data *ffs = container_of(work,
3158                 struct ffs_data, reset_work);
3159         ffs_data_reset(ffs);
3160 }
3161
3162 static int ffs_func_set_alt(struct usb_function *f,
3163                             unsigned interface, unsigned alt)
3164 {
3165         struct ffs_function *func = ffs_func_from_usb(f);
3166         struct ffs_data *ffs = func->ffs;
3167         int ret = 0, intf;
3168
3169         if (alt != (unsigned)-1) {
3170                 intf = ffs_func_revmap_intf(func, interface);
3171                 if (unlikely(intf < 0))
3172                         return intf;
3173         }
3174
3175         if (ffs->func)
3176                 ffs_func_eps_disable(ffs->func);
3177
3178         if (ffs->state == FFS_DEACTIVATED) {
3179                 ffs->state = FFS_CLOSING;
3180                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3181                 schedule_work(&ffs->reset_work);
3182                 return -ENODEV;
3183         }
3184
3185         if (ffs->state != FFS_ACTIVE)
3186                 return -ENODEV;
3187
3188         if (alt == (unsigned)-1) {
3189                 ffs->func = NULL;
3190                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3191                 return 0;
3192         }
3193
3194         ffs->func = func;
3195         ret = ffs_func_eps_enable(func);
3196         if (likely(ret >= 0))
3197                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3198         return ret;
3199 }
3200
3201 static void ffs_func_disable(struct usb_function *f)
3202 {
3203         ffs_func_set_alt(f, 0, (unsigned)-1);
3204 }
3205
3206 static int ffs_func_setup(struct usb_function *f,
3207                           const struct usb_ctrlrequest *creq)
3208 {
3209         struct ffs_function *func = ffs_func_from_usb(f);
3210         struct ffs_data *ffs = func->ffs;
3211         unsigned long flags;
3212         int ret;
3213
3214         ENTER();
3215
3216         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3217         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3218         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3219         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3220         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3221
3222         /*
3223          * Most requests directed to interface go through here
3224          * (notable exceptions are set/get interface) so we need to
3225          * handle them.  All other either handled by composite or
3226          * passed to usb_configuration->setup() (if one is set).  No
3227          * matter, we will handle requests directed to endpoint here
3228          * as well (as it's straightforward).  Other request recipient
3229          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3230          * is being used.
3231          */
3232         if (ffs->state != FFS_ACTIVE)
3233                 return -ENODEV;
3234
3235         switch (creq->bRequestType & USB_RECIP_MASK) {
3236         case USB_RECIP_INTERFACE:
3237                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3238                 if (unlikely(ret < 0))
3239                         return ret;
3240                 break;
3241
3242         case USB_RECIP_ENDPOINT:
3243                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3244                 if (unlikely(ret < 0))
3245                         return ret;
3246                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3247                         ret = func->ffs->eps_addrmap[ret];
3248                 break;
3249
3250         default:
3251                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3252                         ret = le16_to_cpu(creq->wIndex);
3253                 else
3254                         return -EOPNOTSUPP;
3255         }
3256
3257         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3258         ffs->ev.setup = *creq;
3259         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3260         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3261         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3262
3263         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3264 }
3265
3266 static bool ffs_func_req_match(struct usb_function *f,
3267                                const struct usb_ctrlrequest *creq,
3268                                bool config0)
3269 {
3270         struct ffs_function *func = ffs_func_from_usb(f);
3271
3272         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3273                 return false;
3274
3275         switch (creq->bRequestType & USB_RECIP_MASK) {
3276         case USB_RECIP_INTERFACE:
3277                 return (ffs_func_revmap_intf(func,
3278                                              le16_to_cpu(creq->wIndex)) >= 0);
3279         case USB_RECIP_ENDPOINT:
3280                 return (ffs_func_revmap_ep(func,
3281                                            le16_to_cpu(creq->wIndex)) >= 0);
3282         default:
3283                 return (bool) (func->ffs->user_flags &
3284                                FUNCTIONFS_ALL_CTRL_RECIP);
3285         }
3286 }
3287
3288 static void ffs_func_suspend(struct usb_function *f)
3289 {
3290         ENTER();
3291         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3292 }
3293
3294 static void ffs_func_resume(struct usb_function *f)
3295 {
3296         ENTER();
3297         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3298 }
3299
3300
3301 /* Endpoint and interface numbers reverse mapping ***************************/
3302
3303 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3304 {
3305         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3306         return num ? num : -EDOM;
3307 }
3308
3309 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3310 {
3311         short *nums = func->interfaces_nums;
3312         unsigned count = func->ffs->interfaces_count;
3313
3314         for (; count; --count, ++nums) {
3315                 if (*nums >= 0 && *nums == intf)
3316                         return nums - func->interfaces_nums;
3317         }
3318
3319         return -EDOM;
3320 }
3321
3322
3323 /* Devices management *******************************************************/
3324
3325 static LIST_HEAD(ffs_devices);
3326
3327 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3328 {
3329         struct ffs_dev *dev;
3330
3331         list_for_each_entry(dev, &ffs_devices, entry) {
3332                 if (!dev->name || !name)
3333                         continue;
3334                 if (strcmp(dev->name, name) == 0)
3335                         return dev;
3336         }
3337
3338         return NULL;
3339 }
3340
3341 /*
3342  * ffs_lock must be taken by the caller of this function
3343  */
3344 static struct ffs_dev *_ffs_get_single_dev(void)
3345 {
3346         struct ffs_dev *dev;
3347
3348         if (list_is_singular(&ffs_devices)) {
3349                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3350                 if (dev->single)
3351                         return dev;
3352         }
3353
3354         return NULL;
3355 }
3356
3357 /*
3358  * ffs_lock must be taken by the caller of this function
3359  */
3360 static struct ffs_dev *_ffs_find_dev(const char *name)
3361 {
3362         struct ffs_dev *dev;
3363
3364         dev = _ffs_get_single_dev();
3365         if (dev)
3366                 return dev;
3367
3368         return _ffs_do_find_dev(name);
3369 }
3370
3371 /* Configfs support *********************************************************/
3372
3373 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3374 {
3375         return container_of(to_config_group(item), struct f_fs_opts,
3376                             func_inst.group);
3377 }
3378
3379 static void ffs_attr_release(struct config_item *item)
3380 {
3381         struct f_fs_opts *opts = to_ffs_opts(item);
3382
3383         usb_put_function_instance(&opts->func_inst);
3384 }
3385
3386 static struct configfs_item_operations ffs_item_ops = {
3387         .release        = ffs_attr_release,
3388 };
3389
3390 static struct config_item_type ffs_func_type = {
3391         .ct_item_ops    = &ffs_item_ops,
3392         .ct_owner       = THIS_MODULE,
3393 };
3394
3395
3396 /* Function registration interface ******************************************/
3397
3398 static void ffs_free_inst(struct usb_function_instance *f)
3399 {
3400         struct f_fs_opts *opts;
3401
3402         opts = to_f_fs_opts(f);
3403         ffs_dev_lock();
3404         _ffs_free_dev(opts->dev);
3405         ffs_dev_unlock();
3406         kfree(opts);
3407 }
3408
3409 #define MAX_INST_NAME_LEN       40
3410
3411 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3412 {
3413         struct f_fs_opts *opts;
3414         char *ptr;
3415         const char *tmp;
3416         int name_len, ret;
3417
3418         name_len = strlen(name) + 1;
3419         if (name_len > MAX_INST_NAME_LEN)
3420                 return -ENAMETOOLONG;
3421
3422         ptr = kstrndup(name, name_len, GFP_KERNEL);
3423         if (!ptr)
3424                 return -ENOMEM;
3425
3426         opts = to_f_fs_opts(fi);
3427         tmp = NULL;
3428
3429         ffs_dev_lock();
3430
3431         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
3432         ret = _ffs_name_dev(opts->dev, ptr);
3433         if (ret) {
3434                 kfree(ptr);
3435                 ffs_dev_unlock();
3436                 return ret;
3437         }
3438         opts->dev->name_allocated = true;
3439
3440         ffs_dev_unlock();
3441
3442         kfree(tmp);
3443
3444         return 0;
3445 }
3446
3447 static struct usb_function_instance *ffs_alloc_inst(void)
3448 {
3449         struct f_fs_opts *opts;
3450         struct ffs_dev *dev;
3451
3452         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3453         if (!opts)
3454                 return ERR_PTR(-ENOMEM);
3455
3456         opts->func_inst.set_inst_name = ffs_set_inst_name;
3457         opts->func_inst.free_func_inst = ffs_free_inst;
3458         ffs_dev_lock();
3459         dev = _ffs_alloc_dev();
3460         ffs_dev_unlock();
3461         if (IS_ERR(dev)) {
3462                 kfree(opts);
3463                 return ERR_CAST(dev);
3464         }
3465         opts->dev = dev;
3466         dev->opts = opts;
3467
3468         config_group_init_type_name(&opts->func_inst.group, "",
3469                                     &ffs_func_type);
3470         return &opts->func_inst;
3471 }
3472
3473 static void ffs_free(struct usb_function *f)
3474 {
3475         kfree(ffs_func_from_usb(f));
3476 }
3477
3478 static void ffs_func_unbind(struct usb_configuration *c,
3479                             struct usb_function *f)
3480 {
3481         struct ffs_function *func = ffs_func_from_usb(f);
3482         struct ffs_data *ffs = func->ffs;
3483         struct f_fs_opts *opts =
3484                 container_of(f->fi, struct f_fs_opts, func_inst);
3485         struct ffs_ep *ep = func->eps;
3486         unsigned count = ffs->eps_count;
3487         unsigned long flags;
3488
3489         ENTER();
3490         if (ffs->func == func) {
3491                 ffs_func_eps_disable(func);
3492                 ffs->func = NULL;
3493         }
3494
3495         if (!--opts->refcnt)
3496                 functionfs_unbind(ffs);
3497
3498         /* cleanup after autoconfig */
3499         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3500         do {
3501                 if (ep->ep && ep->req)
3502                         usb_ep_free_request(ep->ep, ep->req);
3503                 ep->req = NULL;
3504                 ++ep;
3505         } while (--count);
3506         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3507         kfree(func->eps);
3508         func->eps = NULL;
3509         /*
3510          * eps, descriptors and interfaces_nums are allocated in the
3511          * same chunk so only one free is required.
3512          */
3513         func->function.fs_descriptors = NULL;
3514         func->function.hs_descriptors = NULL;
3515         func->function.ss_descriptors = NULL;
3516         func->function.ssp_descriptors = NULL;
3517         func->interfaces_nums = NULL;
3518
3519         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3520 }
3521
3522 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3523 {
3524         struct ffs_function *func;
3525
3526         ENTER();
3527
3528         func = kzalloc(sizeof(*func), GFP_KERNEL);
3529         if (unlikely(!func))
3530                 return ERR_PTR(-ENOMEM);
3531
3532         func->function.name    = "Function FS Gadget";
3533
3534         func->function.bind    = ffs_func_bind;
3535         func->function.unbind  = ffs_func_unbind;
3536         func->function.set_alt = ffs_func_set_alt;
3537         func->function.disable = ffs_func_disable;
3538         func->function.setup   = ffs_func_setup;
3539         func->function.req_match = ffs_func_req_match;
3540         func->function.suspend = ffs_func_suspend;
3541         func->function.resume  = ffs_func_resume;
3542         func->function.free_func = ffs_free;
3543
3544         return &func->function;
3545 }
3546
3547 /*
3548  * ffs_lock must be taken by the caller of this function
3549  */
3550 static struct ffs_dev *_ffs_alloc_dev(void)
3551 {
3552         struct ffs_dev *dev;
3553         int ret;
3554
3555         if (_ffs_get_single_dev())
3556                         return ERR_PTR(-EBUSY);
3557
3558         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3559         if (!dev)
3560                 return ERR_PTR(-ENOMEM);
3561
3562         if (list_empty(&ffs_devices)) {
3563                 ret = functionfs_init();
3564                 if (ret) {
3565                         kfree(dev);
3566                         return ERR_PTR(ret);
3567                 }
3568         }
3569
3570         list_add(&dev->entry, &ffs_devices);
3571
3572         return dev;
3573 }
3574
3575 /*
3576  * ffs_lock must be taken by the caller of this function
3577  * The caller is responsible for "name" being available whenever f_fs needs it
3578  */
3579 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
3580 {
3581         struct ffs_dev *existing;
3582
3583         existing = _ffs_do_find_dev(name);
3584         if (existing)
3585                 return -EBUSY;
3586
3587         dev->name = name;
3588
3589         return 0;
3590 }
3591
3592 /*
3593  * The caller is responsible for "name" being available whenever f_fs needs it
3594  */
3595 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3596 {
3597         int ret;
3598
3599         ffs_dev_lock();
3600         ret = _ffs_name_dev(dev, name);
3601         ffs_dev_unlock();
3602
3603         return ret;
3604 }
3605 EXPORT_SYMBOL_GPL(ffs_name_dev);
3606
3607 int ffs_single_dev(struct ffs_dev *dev)
3608 {
3609         int ret;
3610
3611         ret = 0;
3612         ffs_dev_lock();
3613
3614         if (!list_is_singular(&ffs_devices))
3615                 ret = -EBUSY;
3616         else
3617                 dev->single = true;
3618
3619         ffs_dev_unlock();
3620         return ret;
3621 }
3622 EXPORT_SYMBOL_GPL(ffs_single_dev);
3623
3624 /*
3625  * ffs_lock must be taken by the caller of this function
3626  */
3627 static void _ffs_free_dev(struct ffs_dev *dev)
3628 {
3629         list_del(&dev->entry);
3630         if (dev->name_allocated)
3631                 kfree(dev->name);
3632
3633         /* Clear the private_data pointer to stop incorrect dev access */
3634         if (dev->ffs_data)
3635                 dev->ffs_data->private_data = NULL;
3636
3637         kfree(dev);
3638         if (list_empty(&ffs_devices))
3639                 functionfs_cleanup();
3640 }
3641
3642 static void *ffs_acquire_dev(const char *dev_name)
3643 {
3644         struct ffs_dev *ffs_dev;
3645
3646         ENTER();
3647         ffs_dev_lock();
3648
3649         ffs_dev = _ffs_find_dev(dev_name);
3650         if (!ffs_dev)
3651                 ffs_dev = ERR_PTR(-ENOENT);
3652         else if (ffs_dev->mounted)
3653                 ffs_dev = ERR_PTR(-EBUSY);
3654         else if (ffs_dev->ffs_acquire_dev_callback &&
3655             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3656                 ffs_dev = ERR_PTR(-ENOENT);
3657         else
3658                 ffs_dev->mounted = true;
3659
3660         ffs_dev_unlock();
3661         return ffs_dev;
3662 }
3663
3664 static void ffs_release_dev(struct ffs_data *ffs_data)
3665 {
3666         struct ffs_dev *ffs_dev;
3667
3668         ENTER();
3669         ffs_dev_lock();
3670
3671         ffs_dev = ffs_data->private_data;
3672         if (ffs_dev) {
3673                 ffs_dev->mounted = false;
3674
3675                 if (ffs_dev->ffs_release_dev_callback)
3676                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3677         }
3678
3679         ffs_dev_unlock();
3680 }
3681
3682 static int ffs_ready(struct ffs_data *ffs)
3683 {
3684         struct ffs_dev *ffs_obj;
3685         int ret = 0;
3686
3687         ENTER();
3688         ffs_dev_lock();
3689
3690         ffs_obj = ffs->private_data;
3691         if (!ffs_obj) {
3692                 ret = -EINVAL;
3693                 goto done;
3694         }
3695         if (WARN_ON(ffs_obj->desc_ready)) {
3696                 ret = -EBUSY;
3697                 goto done;
3698         }
3699
3700         ffs_obj->desc_ready = true;
3701         ffs_obj->ffs_data = ffs;
3702
3703         if (ffs_obj->ffs_ready_callback) {
3704                 ret = ffs_obj->ffs_ready_callback(ffs);
3705                 if (ret)
3706                         goto done;
3707         }
3708
3709         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3710 done:
3711         ffs_dev_unlock();
3712         return ret;
3713 }
3714
3715 static void ffs_closed(struct ffs_data *ffs)
3716 {
3717         struct ffs_dev *ffs_obj;
3718         struct f_fs_opts *opts;
3719         struct config_item *ci;
3720
3721         ENTER();
3722         ffs_dev_lock();
3723
3724         ffs_obj = ffs->private_data;
3725         if (!ffs_obj)
3726                 goto done;
3727
3728         ffs_obj->desc_ready = false;
3729         ffs_obj->ffs_data = NULL;
3730
3731         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3732             ffs_obj->ffs_closed_callback)
3733                 ffs_obj->ffs_closed_callback(ffs);
3734
3735         if (ffs_obj->opts)
3736                 opts = ffs_obj->opts;
3737         else
3738                 goto done;
3739
3740         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3741             || !atomic_read(&opts->func_inst.group.cg_item.ci_kref.refcount))
3742                 goto done;
3743
3744         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3745         ffs_dev_unlock();
3746
3747         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3748                 unregister_gadget_item(ci);
3749         return;
3750 done:
3751         ffs_dev_unlock();
3752 }
3753
3754 /* Misc helper functions ****************************************************/
3755
3756 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3757 {
3758         return nonblock
3759                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3760                 : mutex_lock_interruptible(mutex);
3761 }
3762
3763 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3764 {
3765         char *data;
3766
3767         if (unlikely(!len))
3768                 return NULL;
3769
3770         data = kmalloc(len, GFP_KERNEL);
3771         if (unlikely(!data))
3772                 return ERR_PTR(-ENOMEM);
3773
3774         if (unlikely(copy_from_user(data, buf, len))) {
3775                 kfree(data);
3776                 return ERR_PTR(-EFAULT);
3777         }
3778
3779         pr_vdebug("Buffer from user space:\n");
3780         ffs_dump_mem("", data, len);
3781
3782         return data;
3783 }
3784
3785 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3786 MODULE_LICENSE("GPL");
3787 MODULE_AUTHOR("Michal Nazarewicz");