drivers/usb/gadget/function/f_fs.c

   1 /*
   2  * f_fs.c -- user mode file system API for USB composite function controllers
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  * Author: Michal Nazarewicz <mina86@mina86.com>
   6  *
   7  * Based on inode.c (GadgetFS) which was:
   8  * Copyright (C) 2003-2004 David Brownell
   9  * Copyright (C) 2003 Agilent Technologies
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  */
  16
  17
  18 /* #define DEBUG */
  19 /* #define VERBOSE_DEBUG */
  20
  21 #include <linux/blkdev.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/export.h>
  24 #include <linux/hid.h>
  25 #include <linux/module.h>
  26 #include <linux/sched/signal.h>
  27 #include <linux/uio.h>
  28 #include <asm/unaligned.h>
  29
  30 #include <linux/usb/composite.h>
  31 #include <linux/usb/functionfs.h>
  32
  33 #include <linux/aio.h>
  34 #include <linux/mmu_context.h>
  35 #include <linux/poll.h>
  36 #include <linux/eventfd.h>
  37
  38 #include "u_fs.h"
  39 #include "u_f.h"
  40 #include "u_os_desc.h"
  41 #include "configfs.h"
  42
  43 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  44
  45 /* Reference counter handling */
  46 static void ffs_data_get(struct ffs_data *ffs);
  47 static void ffs_data_put(struct ffs_data *ffs);
  48 /* Creates new ffs_data object. */
  49 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  50         __attribute__((malloc));
  51
  52 /* Opened counter handling. */
  53 static void ffs_data_opened(struct ffs_data *ffs);
  54 static void ffs_data_closed(struct ffs_data *ffs);
  55
  56 /* Called with ffs->mutex held; take over ownership of data. */
  57 static int __must_check
  58 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  59 static int __must_check
  60 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  61
  62
  63 /* The function structure ***************************************************/
  64
  65 struct ffs_ep;
  66
  67 struct ffs_function {
  68         struct usb_configuration        *conf;
  69         struct usb_gadget               *gadget;
  70         struct ffs_data                 *ffs;
  71
  72         struct ffs_ep                   *eps;
  73         u8                              eps_revmap[16];
  74         short                           *interfaces_nums;
  75
  76         struct usb_function             function;
  77 };
  78
  79
  80 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  81 {
  82         return container_of(f, struct ffs_function, function);
  83 }
  84
  85
  86 static inline enum ffs_setup_state
  87 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  88 {
  89         return (enum ffs_setup_state)
  90                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  91 }
  92
  93
  94 static void ffs_func_eps_disable(struct ffs_function *func);
  95 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  96
  97 static int ffs_func_bind(struct usb_configuration *,
  98                          struct usb_function *);
  99 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 100 static void ffs_func_disable(struct usb_function *);
 101 static int ffs_func_setup(struct usb_function *,
 102                           const struct usb_ctrlrequest *);
 103 static bool ffs_func_req_match(struct usb_function *,
 104                                const struct usb_ctrlrequest *,
 105                                bool config0);
 106 static void ffs_func_suspend(struct usb_function *);
 107 static void ffs_func_resume(struct usb_function *);
 108
 109
 110 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 111 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 112
 113
 114 /* The endpoints structures *************************************************/
 115
 116 struct ffs_ep {
 117         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 118         struct usb_request              *req;   /* P: epfile->mutex */
 119
 120         /* [0]: full speed, [1]: high speed, [2]: super speed */
 121         struct usb_endpoint_descriptor  *descs[3];
 122
 123         u8                              num;
 124
 125         int                             status; /* P: epfile->mutex */
 126 };
 127
 128 struct ffs_epfile {
 129         /* Protects ep->ep and ep->req. */
 130         struct mutex                    mutex;
 131
 132         struct ffs_data                 *ffs;
 133         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 134
 135         struct dentry                   *dentry;
 136
 137         /*
 138          * Buffer for holding data from partial reads which may happen since
 139          * we’re rounding user read requests to a multiple of a max packet size.
 140          *
 141          * The pointer is initialised with NULL value and may be set by
 142          * __ffs_epfile_read_data function to point to a temporary buffer.
 143          *
 144          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 145          * data from said buffer and eventually free it.  Importantly, while the
 146          * function is using the buffer, it sets the pointer to NULL.  This is
 147          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 148          * can never run concurrently (they are synchronised by epfile->mutex)
 149          * so the latter will not assign a new value to the pointer.
 150          *
 151          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 152          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 153          * value is crux of the synchronisation between ffs_func_eps_disable and
 154          * __ffs_epfile_read_data.
 155          *
 156          * Once __ffs_epfile_read_data is about to finish it will try to set the
 157          * pointer back to its old value (as described above), but seeing as the
 158          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 159          * the buffer.
 160          *
 161          * == State transitions ==
 162          *
 163          * • ptr == NULL:  (initial state)
 164          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 165          *   ◦ __ffs_epfile_read_buffered:    nop
 166          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 167          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 168          * • ptr == DROP:
 169          *   ◦ __ffs_epfile_read_buffer_free: nop
 170          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 171          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 172          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 173          * • ptr == buf:
 174          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 175          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 176          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 177          *                                    is always called first
 178          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 179          * • ptr == NULL and reading:
 180          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 181          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 182          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 183          *   ◦ reading finishes and …
 184          *     … all data read:               free buf, go to ptr == NULL
 185          *     … otherwise:                   go to ptr == buf and reading
 186          * • ptr == DROP and reading:
 187          *   ◦ __ffs_epfile_read_buffer_free: nop
 188          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 189          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 190          *   ◦ reading finishes:              free buf, go to ptr == DROP
 191          */
 192         struct ffs_buffer               *read_buffer;
 193 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 194
 195         char                            name[5];
 196
 197         unsigned char                   in;     /* P: ffs->eps_lock */
 198         unsigned char                   isoc;   /* P: ffs->eps_lock */
 199
 200         unsigned char                   _pad;
 201 };
 202
 203 struct ffs_buffer {
 204         size_t length;
 205         char *data;
 206         char storage[];
 207 };
 208
 209 /*  ffs_io_data structure ***************************************************/
 210
 211 struct ffs_io_data {
 212         bool aio;
 213         bool read;
 214
 215         struct kiocb *kiocb;
 216         struct iov_iter data;
 217         const void *to_free;
 218         char *buf;
 219
 220         struct mm_struct *mm;
 221         struct work_struct work;
 222
 223         struct usb_ep *ep;
 224         struct usb_request *req;
 225
 226         struct ffs_data *ffs;
 227 };
 228
 229 struct ffs_desc_helper {
 230         struct ffs_data *ffs;
 231         unsigned interfaces_count;
 232         unsigned eps_count;
 233 };
 234
 235 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 236 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 237
 238 static struct dentry *
 239 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 240                    const struct file_operations *fops);
 241
 242 /* Devices management *******************************************************/
 243
 244 DEFINE_MUTEX(ffs_lock);
 245 EXPORT_SYMBOL_GPL(ffs_lock);
 246
 247 static struct ffs_dev *_ffs_find_dev(const char *name);
 248 static struct ffs_dev *_ffs_alloc_dev(void);
 249 static void _ffs_free_dev(struct ffs_dev *dev);
 250 static 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(&ffs->ep0req_completion);
 270 }
 271
 272 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 273 {
 274         struct usb_request *req = ffs->ep0req;
 275         int ret;
 276
 277         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 278
 279         spin_unlock_irq(&ffs->ev.waitq.lock);
 280
 281         req->buf      = data;
 282         req->length   = len;
 283
 284         /*
 285          * UDC layer requires to provide a buffer even for ZLP, but should
 286          * not use it at all. Let's provide some poisoned pointer to catch
 287          * possible bug in the driver.
 288          */
 289         if (req->buf == NULL)
 290                 req->buf = (void *)0xDEADBABE;
 291
 292         reinit_completion(&ffs->ep0req_completion);
 293
 294         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 295         if (unlikely(ret < 0))
 296                 return ret;
 297
 298         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 299         if (unlikely(ret)) {
 300                 usb_ep_dequeue(ffs->gadget->ep0, req);
 301                 return -EINTR;
 302         }
 303
 304         ffs->setup_state = FFS_NO_SETUP;
 305         return req->status ? req->status : req->actual;
 306 }
 307
 308 static int __ffs_ep0_stall(struct ffs_data *ffs)
 309 {
 310         if (ffs->ev.can_stall) {
 311                 pr_vdebug("ep0 stall\n");
 312                 usb_ep_set_halt(ffs->gadget->ep0);
 313                 ffs->setup_state = FFS_NO_SETUP;
 314                 return -EL2HLT;
 315         } else {
 316                 pr_debug("bogus ep0 stall!\n");
 317                 return -ESRCH;
 318         }
 319 }
 320
 321 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 322                              size_t len, loff_t *ptr)
 323 {
 324         struct ffs_data *ffs = file->private_data;
 325         ssize_t ret;
 326         char *data;
 327
 328         ENTER();
 329
 330         /* Fast check if setup was canceled */
 331         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 332                 return -EIDRM;
 333
 334         /* Acquire mutex */
 335         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 336         if (unlikely(ret < 0))
 337                 return ret;
 338
 339         /* Check state */
 340         switch (ffs->state) {
 341         case FFS_READ_DESCRIPTORS:
 342         case FFS_READ_STRINGS:
 343                 /* Copy data */
 344                 if (unlikely(len < 16)) {
 345                         ret = -EINVAL;
 346                         break;
 347                 }
 348
 349                 data = ffs_prepare_buffer(buf, len);
 350                 if (IS_ERR(data)) {
 351                         ret = PTR_ERR(data);
 352                         break;
 353                 }
 354
 355                 /* Handle data */
 356                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 357                         pr_info("read descriptors\n");
 358                         ret = __ffs_data_got_descs(ffs, data, len);
 359                         if (unlikely(ret < 0))
 360                                 break;
 361
 362                         ffs->state = FFS_READ_STRINGS;
 363                         ret = len;
 364                 } else {
 365                         pr_info("read strings\n");
 366                         ret = __ffs_data_got_strings(ffs, data, len);
 367                         if (unlikely(ret < 0))
 368                                 break;
 369
 370                         ret = ffs_epfiles_create(ffs);
 371                         if (unlikely(ret)) {
 372                                 ffs->state = FFS_CLOSING;
 373                                 break;
 374                         }
 375
 376                         ffs->state = FFS_ACTIVE;
 377                         mutex_unlock(&ffs->mutex);
 378
 379                         ret = ffs_ready(ffs);
 380                         if (unlikely(ret < 0)) {
 381                                 ffs->state = FFS_CLOSING;
 382                                 return ret;
 383                         }
 384
 385                         return len;
 386                 }
 387                 break;
 388
 389         case FFS_ACTIVE:
 390                 data = NULL;
 391                 /*
 392                  * We're called from user space, we can use _irq
 393                  * rather then _irqsave
 394                  */
 395                 spin_lock_irq(&ffs->ev.waitq.lock);
 396                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 397                 case FFS_SETUP_CANCELLED:
 398                         ret = -EIDRM;
 399                         goto done_spin;
 400
 401                 case FFS_NO_SETUP:
 402                         ret = -ESRCH;
 403                         goto done_spin;
 404
 405                 case FFS_SETUP_PENDING:
 406                         break;
 407                 }
 408
 409                 /* FFS_SETUP_PENDING */
 410                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 411                         spin_unlock_irq(&ffs->ev.waitq.lock);
 412                         ret = __ffs_ep0_stall(ffs);
 413                         break;
 414                 }
 415
 416                 /* FFS_SETUP_PENDING and not stall */
 417                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 418
 419                 spin_unlock_irq(&ffs->ev.waitq.lock);
 420
 421                 data = ffs_prepare_buffer(buf, len);
 422                 if (IS_ERR(data)) {
 423                         ret = PTR_ERR(data);
 424                         break;
 425                 }
 426
 427                 spin_lock_irq(&ffs->ev.waitq.lock);
 428
 429                 /*
 430                  * We are guaranteed to be still in FFS_ACTIVE state
 431                  * but the state of setup could have changed from
 432                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 433                  * to check for that.  If that happened we copied data
 434                  * from user space in vain but it's unlikely.
 435                  *
 436                  * For sure we are not in FFS_NO_SETUP since this is
 437                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 438                  * transition can be performed and it's protected by
 439                  * mutex.
 440                  */
 441                 if (ffs_setup_state_clear_cancelled(ffs) ==
 442                     FFS_SETUP_CANCELLED) {
 443                         ret = -EIDRM;
 444 done_spin:
 445                         spin_unlock_irq(&ffs->ev.waitq.lock);
 446                 } else {
 447                         /* unlocks spinlock */
 448                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 449                 }
 450                 kfree(data);
 451                 break;
 452
 453         default:
 454                 ret = -EBADFD;
 455                 break;
 456         }
 457
 458         mutex_unlock(&ffs->mutex);
 459         return ret;
 460 }
 461
 462 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 463 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 464                                      size_t n)
 465 {
 466         /*
 467          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 468          * size of ffs->ev.types array (which is four) so that's how much space
 469          * we reserve.
 470          */
 471         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 472         const size_t size = n * sizeof *events;
 473         unsigned i = 0;
 474
 475         memset(events, 0, size);
 476
 477         do {
 478                 events[i].type = ffs->ev.types[i];
 479                 if (events[i].type == FUNCTIONFS_SETUP) {
 480                         events[i].u.setup = ffs->ev.setup;
 481                         ffs->setup_state = FFS_SETUP_PENDING;
 482                 }
 483         } while (++i < n);
 484
 485         ffs->ev.count -= n;
 486         if (ffs->ev.count)
 487                 memmove(ffs->ev.types, ffs->ev.types + n,
 488                         ffs->ev.count * sizeof *ffs->ev.types);
 489
 490         spin_unlock_irq(&ffs->ev.waitq.lock);
 491         mutex_unlock(&ffs->mutex);
 492
 493         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 494 }
 495
 496 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 497                             size_t len, loff_t *ptr)
 498 {
 499         struct ffs_data *ffs = file->private_data;
 500         char *data = NULL;
 501         size_t n;
 502         int ret;
 503
 504         ENTER();
 505
 506         /* Fast check if setup was canceled */
 507         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 508                 return -EIDRM;
 509
 510         /* Acquire mutex */
 511         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 512         if (unlikely(ret < 0))
 513                 return ret;
 514
 515         /* Check state */
 516         if (ffs->state != FFS_ACTIVE) {
 517                 ret = -EBADFD;
 518                 goto done_mutex;
 519         }
 520
 521         /*
 522          * We're called from user space, we can use _irq rather then
 523          * _irqsave
 524          */
 525         spin_lock_irq(&ffs->ev.waitq.lock);
 526
 527         switch (ffs_setup_state_clear_cancelled(ffs)) {
 528         case FFS_SETUP_CANCELLED:
 529                 ret = -EIDRM;
 530                 break;
 531
 532         case FFS_NO_SETUP:
 533                 n = len / sizeof(struct usb_functionfs_event);
 534                 if (unlikely(!n)) {
 535                         ret = -EINVAL;
 536                         break;
 537                 }
 538
 539                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 540                         ret = -EAGAIN;
 541                         break;
 542                 }
 543
 544                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 545                                                         ffs->ev.count)) {
 546                         ret = -EINTR;
 547                         break;
 548                 }
 549
 550                 return __ffs_ep0_read_events(ffs, buf,
 551                                              min(n, (size_t)ffs->ev.count));
 552
 553         case FFS_SETUP_PENDING:
 554                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 555                         spin_unlock_irq(&ffs->ev.waitq.lock);
 556                         ret = __ffs_ep0_stall(ffs);
 557                         goto done_mutex;
 558                 }
 559
 560                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 561
 562                 spin_unlock_irq(&ffs->ev.waitq.lock);
 563
 564                 if (likely(len)) {
 565                         data = kmalloc(len, GFP_KERNEL);
 566                         if (unlikely(!data)) {
 567                                 ret = -ENOMEM;
 568                                 goto done_mutex;
 569                         }
 570                 }
 571
 572                 spin_lock_irq(&ffs->ev.waitq.lock);
 573
 574                 /* See ffs_ep0_write() */
 575                 if (ffs_setup_state_clear_cancelled(ffs) ==
 576                     FFS_SETUP_CANCELLED) {
 577                         ret = -EIDRM;
 578                         break;
 579                 }
 580
 581                 /* unlocks spinlock */
 582                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 583                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 584                         ret = -EFAULT;
 585                 goto done_mutex;
 586
 587         default:
 588                 ret = -EBADFD;
 589                 break;
 590         }
 591
 592         spin_unlock_irq(&ffs->ev.waitq.lock);
 593 done_mutex:
 594         mutex_unlock(&ffs->mutex);
 595         kfree(data);
 596         return ret;
 597 }
 598
 599 static int ffs_ep0_open(struct inode *inode, struct file *file)
 600 {
 601         struct ffs_data *ffs = inode->i_private;
 602
 603         ENTER();
 604
 605         if (unlikely(ffs->state == FFS_CLOSING))
 606                 return -EBUSY;
 607
 608         file->private_data = ffs;
 609         ffs_data_opened(ffs);
 610
 611         return 0;
 612 }
 613
 614 static int ffs_ep0_release(struct inode *inode, struct file *file)
 615 {
 616         struct ffs_data *ffs = file->private_data;
 617
 618         ENTER();
 619
 620         ffs_data_closed(ffs);
 621
 622         return 0;
 623 }
 624
 625 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 626 {
 627         struct ffs_data *ffs = file->private_data;
 628         struct usb_gadget *gadget = ffs->gadget;
 629         long ret;
 630
 631         ENTER();
 632
 633         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 634                 struct ffs_function *func = ffs->func;
 635                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 636         } else if (gadget && gadget->ops->ioctl) {
 637                 ret = gadget->ops->ioctl(gadget, code, value);
 638         } else {
 639                 ret = -ENOTTY;
 640         }
 641
 642         return ret;
 643 }
 644
 645 static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
 646 {
 647         struct ffs_data *ffs = file->private_data;
 648         unsigned int mask = POLLWRNORM;
 649         int ret;
 650
 651         poll_wait(file, &ffs->ev.waitq, wait);
 652
 653         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 654         if (unlikely(ret < 0))
 655                 return mask;
 656
 657         switch (ffs->state) {
 658         case FFS_READ_DESCRIPTORS:
 659         case FFS_READ_STRINGS:
 660                 mask |= POLLOUT;
 661                 break;
 662
 663         case FFS_ACTIVE:
 664                 switch (ffs->setup_state) {
 665                 case FFS_NO_SETUP:
 666                         if (ffs->ev.count)
 667                                 mask |= POLLIN;
 668                         break;
 669
 670                 case FFS_SETUP_PENDING:
 671                 case FFS_SETUP_CANCELLED:
 672                         mask |= (POLLIN | POLLOUT);
 673                         break;
 674                 }
 675         case FFS_CLOSING:
 676                 break;
 677         case FFS_DEACTIVATED:
 678                 break;
 679         }
 680
 681         mutex_unlock(&ffs->mutex);
 682
 683         return mask;
 684 }
 685
 686 static const struct file_operations ffs_ep0_operations = {
 687         .llseek =       no_llseek,
 688
 689         .open =         ffs_ep0_open,
 690         .write =        ffs_ep0_write,
 691         .read =         ffs_ep0_read,
 692         .release =      ffs_ep0_release,
 693         .unlocked_ioctl =       ffs_ep0_ioctl,
 694         .poll =         ffs_ep0_poll,
 695 };
 696
 697
 698 /* "Normal" endpoints operations ********************************************/
 699
 700 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 701 {
 702         ENTER();
 703         if (likely(req->context)) {
 704                 struct ffs_ep *ep = _ep->driver_data;
 705                 ep->status = req->status ? req->status : req->actual;
 706                 complete(req->context);
 707         }
 708 }
 709
 710 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 711 {
 712         ssize_t ret = copy_to_iter(data, data_len, iter);
 713         if (likely(ret == data_len))
 714                 return ret;
 715
 716         if (unlikely(iov_iter_count(iter)))
 717                 return -EFAULT;
 718
 719         /*
 720          * Dear user space developer!
 721          *
 722          * TL;DR: To stop getting below error message in your kernel log, change
 723          * user space code using functionfs to align read buffers to a max
 724          * packet size.
 725          *
 726          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 727          * packet size.  When unaligned buffer is passed to functionfs, it
 728          * internally uses a larger, aligned buffer so that such UDCs are happy.
 729          *
 730          * Unfortunately, this means that host may send more data than was
 731          * requested in read(2) system call.  f_fs doesn’t know what to do with
 732          * that excess data so it simply drops it.
 733          *
 734          * Was the buffer aligned in the first place, no such problem would
 735          * happen.
 736          *
 737          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 738          * by splitting a request into multiple parts.  This splitting may still
 739          * be a problem though so it’s likely best to align the buffer
 740          * regardless of it being AIO or not..
 741          *
 742          * This only affects OUT endpoints, i.e. reading data with a read(2),
 743          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 744          * affected.
 745          */
 746         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 747                "Align read buffer size to max packet size to avoid the problem.\n",
 748                data_len, ret);
 749
 750         return ret;
 751 }
 752
 753 static void ffs_user_copy_worker(struct work_struct *work)
 754 {
 755         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 756                                                    work);
 757         int ret = io_data->req->status ? io_data->req->status :
 758                                          io_data->req->actual;
 759         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 760
 761         if (io_data->read && ret > 0) {
 762                 use_mm(io_data->mm);
 763                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 764                 unuse_mm(io_data->mm);
 765         }
 766
 767         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 768
 769         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 770                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 771
 772         usb_ep_free_request(io_data->ep, io_data->req);
 773
 774         if (io_data->read)
 775                 kfree(io_data->to_free);
 776         kfree(io_data->buf);
 777         kfree(io_data);
 778 }
 779
 780 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 781                                          struct usb_request *req)
 782 {
 783         struct ffs_io_data *io_data = req->context;
 784         struct ffs_data *ffs = io_data->ffs;
 785
 786         ENTER();
 787
 788         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 789         queue_work(ffs->io_completion_wq, &io_data->work);
 790 }
 791
 792 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 793 {
 794         /*
 795          * See comment in struct ffs_epfile for full read_buffer pointer
 796          * synchronisation story.
 797          */
 798         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 799         if (buf && buf != READ_BUFFER_DROP)
 800                 kfree(buf);
 801 }
 802
 803 /* Assumes epfile->mutex is held. */
 804 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 805                                           struct iov_iter *iter)
 806 {
 807         /*
 808          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 809          * the buffer while we are using it.  See comment in struct ffs_epfile
 810          * for full read_buffer pointer synchronisation story.
 811          */
 812         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 813         ssize_t ret;
 814         if (!buf || buf == READ_BUFFER_DROP)
 815                 return 0;
 816
 817         ret = copy_to_iter(buf->data, buf->length, iter);
 818         if (buf->length == ret) {
 819                 kfree(buf);
 820                 return ret;
 821         }
 822
 823         if (unlikely(iov_iter_count(iter))) {
 824                 ret = -EFAULT;
 825         } else {
 826                 buf->length -= ret;
 827                 buf->data += ret;
 828         }
 829
 830         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 831                 kfree(buf);
 832
 833         return ret;
 834 }
 835
 836 /* Assumes epfile->mutex is held. */
 837 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 838                                       void *data, int data_len,
 839                                       struct iov_iter *iter)
 840 {
 841         struct ffs_buffer *buf;
 842
 843         ssize_t ret = copy_to_iter(data, data_len, iter);
 844         if (likely(data_len == ret))
 845                 return ret;
 846
 847         if (unlikely(iov_iter_count(iter)))
 848                 return -EFAULT;
 849
 850         /* See ffs_copy_to_iter for more context. */
 851         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 852                 data_len, ret);
 853
 854         data_len -= ret;
 855         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 856         if (!buf)
 857                 return -ENOMEM;
 858         buf->length = data_len;
 859         buf->data = buf->storage;
 860         memcpy(buf->storage, data + ret, data_len);
 861
 862         /*
 863          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 864          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 865          * in struct ffs_epfile for full read_buffer pointer synchronisation
 866          * story.
 867          */
 868         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 869                 kfree(buf);
 870
 871         return ret;
 872 }
 873
 874 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 875 {
 876         struct ffs_epfile *epfile = file->private_data;
 877         struct usb_request *req;
 878         struct ffs_ep *ep;
 879         char *data = NULL;
 880         ssize_t ret, data_len = -EINVAL;
 881         int halt;
 882
 883         /* Are we still active? */
 884         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 885                 return -ENODEV;
 886
 887         /* Wait for endpoint to be enabled */
 888         ep = epfile->ep;
 889         if (!ep) {
 890                 if (file->f_flags & O_NONBLOCK)
 891                         return -EAGAIN;
 892
 893                 ret = wait_event_interruptible(
 894                                 epfile->ffs->wait, (ep = epfile->ep));
 895                 if (ret)
 896                         return -EINTR;
 897         }
 898
 899         /* Do we halt? */
 900         halt = (!io_data->read == !epfile->in);
 901         if (halt && epfile->isoc)
 902                 return -EINVAL;
 903
 904         /* We will be using request and read_buffer */
 905         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 906         if (unlikely(ret))
 907                 goto error;
 908
 909         /* Allocate & copy */
 910         if (!halt) {
 911                 struct usb_gadget *gadget;
 912
 913                 /*
 914                  * Do we have buffered data from previous partial read?  Check
 915                  * that for synchronous case only because we do not have
 916                  * facility to ‘wake up’ a pending asynchronous read and push
 917                  * buffered data to it which we would need to make things behave
 918                  * consistently.
 919                  */
 920                 if (!io_data->aio && io_data->read) {
 921                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 922                         if (ret)
 923                                 goto error_mutex;
 924                 }
 925
 926                 /*
 927                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 928                  * before the waiting completes, so do not assign to 'gadget'
 929                  * earlier
 930                  */
 931                 gadget = epfile->ffs->gadget;
 932
 933                 spin_lock_irq(&epfile->ffs->eps_lock);
 934                 /* In the meantime, endpoint got disabled or changed. */
 935                 if (epfile->ep != ep) {
 936                         ret = -ESHUTDOWN;
 937                         goto error_lock;
 938                 }
 939                 data_len = iov_iter_count(&io_data->data);
 940                 /*
 941                  * Controller may require buffer size to be aligned to
 942                  * maxpacketsize of an out endpoint.
 943                  */
 944                 if (io_data->read)
 945                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
 946                 spin_unlock_irq(&epfile->ffs->eps_lock);
 947
 948                 data = kmalloc(data_len, GFP_KERNEL);
 949                 if (unlikely(!data)) {
 950                         ret = -ENOMEM;
 951                         goto error_mutex;
 952                 }
 953                 if (!io_data->read &&
 954                     !copy_from_iter_full(data, data_len, &io_data->data)) {
 955                         ret = -EFAULT;
 956                         goto error_mutex;
 957                 }
 958         }
 959
 960         spin_lock_irq(&epfile->ffs->eps_lock);
 961
 962         if (epfile->ep != ep) {
 963                 /* In the meantime, endpoint got disabled or changed. */
 964                 ret = -ESHUTDOWN;
 965         } else if (halt) {
 966                 ret = usb_ep_set_halt(ep->ep);
 967                 if (!ret)
 968                         ret = -EBADMSG;
 969         } else if (unlikely(data_len == -EINVAL)) {
 970                 /*
 971                  * Sanity Check: even though data_len can't be used
 972                  * uninitialized at the time I write this comment, some
 973                  * compilers complain about this situation.
 974                  * In order to keep the code clean from warnings, data_len is
 975                  * being initialized to -EINVAL during its declaration, which
 976                  * means we can't rely on compiler anymore to warn no future
 977                  * changes won't result in data_len being used uninitialized.
 978                  * For such reason, we're adding this redundant sanity check
 979                  * here.
 980                  */
 981                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
 982                 ret = -EINVAL;
 983         } else if (!io_data->aio) {
 984                 DECLARE_COMPLETION_ONSTACK(done);
 985                 bool interrupted = false;
 986
 987                 req = ep->req;
 988                 req->buf      = data;
 989                 req->length   = data_len;
 990
 991                 req->context  = &done;
 992                 req->complete = ffs_epfile_io_complete;
 993
 994                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 995                 if (unlikely(ret < 0))
 996                         goto error_lock;
 997
 998                 spin_unlock_irq(&epfile->ffs->eps_lock);
 999
1000                 if (unlikely(wait_for_completion_interruptible(&done))) {
1001                         /*
1002                          * To avoid race condition with ffs_epfile_io_complete,
1003                          * dequeue the request first then check
1004                          * status. usb_ep_dequeue API should guarantee no race
1005                          * condition with req->complete callback.
1006                          */
1007                         usb_ep_dequeue(ep->ep, req);
1008                         interrupted = ep->status < 0;
1009                 }
1010
1011                 if (interrupted)
1012                         ret = -EINTR;
1013                 else if (io_data->read && ep->status > 0)
1014                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1015                                                      &io_data->data);
1016                 else
1017                         ret = ep->status;
1018                 goto error_mutex;
1019         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_KERNEL))) {
1020                 ret = -ENOMEM;
1021         } else {
1022                 req->buf      = data;
1023                 req->length   = data_len;
1024
1025                 io_data->buf = data;
1026                 io_data->ep = ep->ep;
1027                 io_data->req = req;
1028                 io_data->ffs = epfile->ffs;
1029
1030                 req->context  = io_data;
1031                 req->complete = ffs_epfile_async_io_complete;
1032
1033                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1034                 if (unlikely(ret)) {
1035                         usb_ep_free_request(ep->ep, req);
1036                         goto error_lock;
1037                 }
1038
1039                 ret = -EIOCBQUEUED;
1040                 /*
1041                  * Do not kfree the buffer in this function.  It will be freed
1042                  * by ffs_user_copy_worker.
1043                  */
1044                 data = NULL;
1045         }
1046
1047 error_lock:
1048         spin_unlock_irq(&epfile->ffs->eps_lock);
1049 error_mutex:
1050         mutex_unlock(&epfile->mutex);
1051 error:
1052         kfree(data);
1053         return ret;
1054 }
1055
1056 static int
1057 ffs_epfile_open(struct inode *inode, struct file *file)
1058 {
1059         struct ffs_epfile *epfile = inode->i_private;
1060
1061         ENTER();
1062
1063         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1064                 return -ENODEV;
1065
1066         file->private_data = epfile;
1067         ffs_data_opened(epfile->ffs);
1068
1069         return 0;
1070 }
1071
1072 static int ffs_aio_cancel(struct kiocb *kiocb)
1073 {
1074         struct ffs_io_data *io_data = kiocb->private;
1075         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1076         int value;
1077
1078         ENTER();
1079
1080         spin_lock_irq(&epfile->ffs->eps_lock);
1081
1082         if (likely(io_data && io_data->ep && io_data->req))
1083                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1084         else
1085                 value = -EINVAL;
1086
1087         spin_unlock_irq(&epfile->ffs->eps_lock);
1088
1089         return value;
1090 }
1091
1092 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1093 {
1094         struct ffs_io_data io_data, *p = &io_data;
1095         ssize_t res;
1096
1097         ENTER();
1098
1099         if (!is_sync_kiocb(kiocb)) {
1100                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1101                 if (unlikely(!p))
1102                         return -ENOMEM;
1103                 p->aio = true;
1104         } else {
1105                 p->aio = false;
1106         }
1107
1108         p->read = false;
1109         p->kiocb = kiocb;
1110         p->data = *from;
1111         p->mm = current->mm;
1112
1113         kiocb->private = p;
1114
1115         if (p->aio)
1116                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1117
1118         res = ffs_epfile_io(kiocb->ki_filp, p);
1119         if (res == -EIOCBQUEUED)
1120                 return res;
1121         if (p->aio)
1122                 kfree(p);
1123         else
1124                 *from = p->data;
1125         return res;
1126 }
1127
1128 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1129 {
1130         struct ffs_io_data io_data, *p = &io_data;
1131         ssize_t res;
1132
1133         ENTER();
1134
1135         if (!is_sync_kiocb(kiocb)) {
1136                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1137                 if (unlikely(!p))
1138                         return -ENOMEM;
1139                 p->aio = true;
1140         } else {
1141                 p->aio = false;
1142         }
1143
1144         p->read = true;
1145         p->kiocb = kiocb;
1146         if (p->aio) {
1147                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1148                 if (!p->to_free) {
1149                         kfree(p);
1150                         return -ENOMEM;
1151                 }
1152         } else {
1153                 p->data = *to;
1154                 p->to_free = NULL;
1155         }
1156         p->mm = current->mm;
1157
1158         kiocb->private = p;
1159
1160         if (p->aio)
1161                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1162
1163         res = ffs_epfile_io(kiocb->ki_filp, p);
1164         if (res == -EIOCBQUEUED)
1165                 return res;
1166
1167         if (p->aio) {
1168                 kfree(p->to_free);
1169                 kfree(p);
1170         } else {
1171                 *to = p->data;
1172         }
1173         return res;
1174 }
1175
1176 static int
1177 ffs_epfile_release(struct inode *inode, struct file *file)
1178 {
1179         struct ffs_epfile *epfile = inode->i_private;
1180
1181         ENTER();
1182
1183         __ffs_epfile_read_buffer_free(epfile);
1184         ffs_data_closed(epfile->ffs);
1185
1186         return 0;
1187 }
1188
1189 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1190                              unsigned long value)
1191 {
1192         struct ffs_epfile *epfile = file->private_data;
1193         struct ffs_ep *ep;
1194         int ret;
1195
1196         ENTER();
1197
1198         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1199                 return -ENODEV;
1200
1201         /* Wait for endpoint to be enabled */
1202         ep = epfile->ep;
1203         if (!ep) {
1204                 if (file->f_flags & O_NONBLOCK)
1205                         return -EAGAIN;
1206
1207                 ret = wait_event_interruptible(
1208                                 epfile->ffs->wait, (ep = epfile->ep));
1209                 if (ret)
1210                         return -EINTR;
1211         }
1212
1213         spin_lock_irq(&epfile->ffs->eps_lock);
1214
1215         /* In the meantime, endpoint got disabled or changed. */
1216         if (epfile->ep != ep) {
1217                 spin_unlock_irq(&epfile->ffs->eps_lock);
1218                 return -ESHUTDOWN;
1219         }
1220
1221         switch (code) {
1222         case FUNCTIONFS_FIFO_STATUS:
1223                 ret = usb_ep_fifo_status(epfile->ep->ep);
1224                 break;
1225         case FUNCTIONFS_FIFO_FLUSH:
1226                 usb_ep_fifo_flush(epfile->ep->ep);
1227                 ret = 0;
1228                 break;
1229         case FUNCTIONFS_CLEAR_HALT:
1230                 ret = usb_ep_clear_halt(epfile->ep->ep);
1231                 break;
1232         case FUNCTIONFS_ENDPOINT_REVMAP:
1233                 ret = epfile->ep->num;
1234                 break;
1235         case FUNCTIONFS_ENDPOINT_DESC:
1236         {
1237                 int desc_idx;
1238                 struct usb_endpoint_descriptor *desc;
1239
1240                 switch (epfile->ffs->gadget->speed) {
1241                 case USB_SPEED_SUPER:
1242                         desc_idx = 2;
1243                         break;
1244                 case USB_SPEED_HIGH:
1245                         desc_idx = 1;
1246                         break;
1247                 default:
1248                         desc_idx = 0;
1249                 }
1250                 desc = epfile->ep->descs[desc_idx];
1251
1252                 spin_unlock_irq(&epfile->ffs->eps_lock);
1253                 ret = copy_to_user((void *)value, desc, desc->bLength);
1254                 if (ret)
1255                         ret = -EFAULT;
1256                 return ret;
1257         }
1258         default:
1259                 ret = -ENOTTY;
1260         }
1261         spin_unlock_irq(&epfile->ffs->eps_lock);
1262
1263         return ret;
1264 }
1265
1266 static const struct file_operations ffs_epfile_operations = {
1267         .llseek =       no_llseek,
1268
1269         .open =         ffs_epfile_open,
1270         .write_iter =   ffs_epfile_write_iter,
1271         .read_iter =    ffs_epfile_read_iter,
1272         .release =      ffs_epfile_release,
1273         .unlocked_ioctl =       ffs_epfile_ioctl,
1274 };
1275
1276
1277 /* File system and super block operations ***********************************/
1278
1279 /*
1280  * Mounting the file system creates a controller file, used first for
1281  * function configuration then later for event monitoring.
1282  */
1283
1284 static struct inode *__must_check
1285 ffs_sb_make_inode(struct super_block *sb, void *data,
1286                   const struct file_operations *fops,
1287                   const struct inode_operations *iops,
1288                   struct ffs_file_perms *perms)
1289 {
1290         struct inode *inode;
1291
1292         ENTER();
1293
1294         inode = new_inode(sb);
1295
1296         if (likely(inode)) {
1297                 struct timespec ts = current_time(inode);
1298
1299                 inode->i_ino     = get_next_ino();
1300                 inode->i_mode    = perms->mode;
1301                 inode->i_uid     = perms->uid;
1302                 inode->i_gid     = perms->gid;
1303                 inode->i_atime   = ts;
1304                 inode->i_mtime   = ts;
1305                 inode->i_ctime   = ts;
1306                 inode->i_private = data;
1307                 if (fops)
1308                         inode->i_fop = fops;
1309                 if (iops)
1310                         inode->i_op  = iops;
1311         }
1312
1313         return inode;
1314 }
1315
1316 /* Create "regular" file */
1317 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1318                                         const char *name, void *data,
1319                                         const struct file_operations *fops)
1320 {
1321         struct ffs_data *ffs = sb->s_fs_info;
1322         struct dentry   *dentry;
1323         struct inode    *inode;
1324
1325         ENTER();
1326
1327         dentry = d_alloc_name(sb->s_root, name);
1328         if (unlikely(!dentry))
1329                 return NULL;
1330
1331         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1332         if (unlikely(!inode)) {
1333                 dput(dentry);
1334                 return NULL;
1335         }
1336
1337         d_add(dentry, inode);
1338         return dentry;
1339 }
1340
1341 /* Super block */
1342 static const struct super_operations ffs_sb_operations = {
1343         .statfs =       simple_statfs,
1344         .drop_inode =   generic_delete_inode,
1345 };
1346
1347 struct ffs_sb_fill_data {
1348         struct ffs_file_perms perms;
1349         umode_t root_mode;
1350         const char *dev_name;
1351         bool no_disconnect;
1352         struct ffs_data *ffs_data;
1353 };
1354
1355 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1356 {
1357         struct ffs_sb_fill_data *data = _data;
1358         struct inode    *inode;
1359         struct ffs_data *ffs = data->ffs_data;
1360
1361         ENTER();
1362
1363         ffs->sb              = sb;
1364         data->ffs_data       = NULL;
1365         sb->s_fs_info        = ffs;
1366         sb->s_blocksize      = PAGE_SIZE;
1367         sb->s_blocksize_bits = PAGE_SHIFT;
1368         sb->s_magic          = FUNCTIONFS_MAGIC;
1369         sb->s_op             = &ffs_sb_operations;
1370         sb->s_time_gran      = 1;
1371
1372         /* Root inode */
1373         data->perms.mode = data->root_mode;
1374         inode = ffs_sb_make_inode(sb, NULL,
1375                                   &simple_dir_operations,
1376                                   &simple_dir_inode_operations,
1377                                   &data->perms);
1378         sb->s_root = d_make_root(inode);
1379         if (unlikely(!sb->s_root))
1380                 return -ENOMEM;
1381
1382         /* EP0 file */
1383         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1384                                          &ffs_ep0_operations)))
1385                 return -ENOMEM;
1386
1387         return 0;
1388 }
1389
1390 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1391 {
1392         ENTER();
1393
1394         if (!opts || !*opts)
1395                 return 0;
1396
1397         for (;;) {
1398                 unsigned long value;
1399                 char *eq, *comma;
1400
1401                 /* Option limit */
1402                 comma = strchr(opts, ',');
1403                 if (comma)
1404                         *comma = 0;
1405
1406                 /* Value limit */
1407                 eq = strchr(opts, '=');
1408                 if (unlikely(!eq)) {
1409                         pr_err("'=' missing in %s\n", opts);
1410                         return -EINVAL;
1411                 }
1412                 *eq = 0;
1413
1414                 /* Parse value */
1415                 if (kstrtoul(eq + 1, 0, &value)) {
1416                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1417                         return -EINVAL;
1418                 }
1419
1420                 /* Interpret option */
1421                 switch (eq - opts) {
1422                 case 13:
1423                         if (!memcmp(opts, "no_disconnect", 13))
1424                                 data->no_disconnect = !!value;
1425                         else
1426                                 goto invalid;
1427                         break;
1428                 case 5:
1429                         if (!memcmp(opts, "rmode", 5))
1430                                 data->root_mode  = (value & 0555) | S_IFDIR;
1431                         else if (!memcmp(opts, "fmode", 5))
1432                                 data->perms.mode = (value & 0666) | S_IFREG;
1433                         else
1434                                 goto invalid;
1435                         break;
1436
1437                 case 4:
1438                         if (!memcmp(opts, "mode", 4)) {
1439                                 data->root_mode  = (value & 0555) | S_IFDIR;
1440                                 data->perms.mode = (value & 0666) | S_IFREG;
1441                         } else {
1442                                 goto invalid;
1443                         }
1444                         break;
1445
1446                 case 3:
1447                         if (!memcmp(opts, "uid", 3)) {
1448                                 data->perms.uid = make_kuid(current_user_ns(), value);
1449                                 if (!uid_valid(data->perms.uid)) {
1450                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1451                                         return -EINVAL;
1452                                 }
1453                         } else if (!memcmp(opts, "gid", 3)) {
1454                                 data->perms.gid = make_kgid(current_user_ns(), value);
1455                                 if (!gid_valid(data->perms.gid)) {
1456                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1457                                         return -EINVAL;
1458                                 }
1459                         } else {
1460                                 goto invalid;
1461                         }
1462                         break;
1463
1464                 default:
1465 invalid:
1466                         pr_err("%s: invalid option\n", opts);
1467                         return -EINVAL;
1468                 }
1469
1470                 /* Next iteration */
1471                 if (!comma)
1472                         break;
1473                 opts = comma + 1;
1474         }
1475
1476         return 0;
1477 }
1478
1479 /* "mount -t functionfs dev_name /dev/function" ends up here */
1480
1481 static struct dentry *
1482 ffs_fs_mount(struct file_system_type *t, int flags,
1483               const char *dev_name, void *opts)
1484 {
1485         struct ffs_sb_fill_data data = {
1486                 .perms = {
1487                         .mode = S_IFREG | 0600,
1488                         .uid = GLOBAL_ROOT_UID,
1489                         .gid = GLOBAL_ROOT_GID,
1490                 },
1491                 .root_mode = S_IFDIR | 0500,
1492                 .no_disconnect = false,
1493         };
1494         struct dentry *rv;
1495         int ret;
1496         void *ffs_dev;
1497         struct ffs_data *ffs;
1498
1499         ENTER();
1500
1501         ret = ffs_fs_parse_opts(&data, opts);
1502         if (unlikely(ret < 0))
1503                 return ERR_PTR(ret);
1504
1505         ffs = ffs_data_new(dev_name);
1506         if (unlikely(!ffs))
1507                 return ERR_PTR(-ENOMEM);
1508         ffs->file_perms = data.perms;
1509         ffs->no_disconnect = data.no_disconnect;
1510
1511         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1512         if (unlikely(!ffs->dev_name)) {
1513                 ffs_data_put(ffs);
1514                 return ERR_PTR(-ENOMEM);
1515         }
1516
1517         ffs_dev = ffs_acquire_dev(dev_name);
1518         if (IS_ERR(ffs_dev)) {
1519                 ffs_data_put(ffs);
1520                 return ERR_CAST(ffs_dev);
1521         }
1522         ffs->private_data = ffs_dev;
1523         data.ffs_data = ffs;
1524
1525         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1526         if (IS_ERR(rv) && data.ffs_data) {
1527                 ffs_release_dev(data.ffs_data);
1528                 ffs_data_put(data.ffs_data);
1529         }
1530         return rv;
1531 }
1532
1533 static void
1534 ffs_fs_kill_sb(struct super_block *sb)
1535 {
1536         ENTER();
1537
1538         kill_litter_super(sb);
1539         if (sb->s_fs_info) {
1540                 ffs_release_dev(sb->s_fs_info);
1541                 ffs_data_closed(sb->s_fs_info);
1542                 ffs_data_put(sb->s_fs_info);
1543         }
1544 }
1545
1546 static struct file_system_type ffs_fs_type = {
1547         .owner          = THIS_MODULE,
1548         .name           = "functionfs",
1549         .mount          = ffs_fs_mount,
1550         .kill_sb        = ffs_fs_kill_sb,
1551 };
1552 MODULE_ALIAS_FS("functionfs");
1553
1554
1555 /* Driver's main init/cleanup functions *************************************/
1556
1557 static int functionfs_init(void)
1558 {
1559         int ret;
1560
1561         ENTER();
1562
1563         ret = register_filesystem(&ffs_fs_type);
1564         if (likely(!ret))
1565                 pr_info("file system registered\n");
1566         else
1567                 pr_err("failed registering file system (%d)\n", ret);
1568
1569         return ret;
1570 }
1571
1572 static void functionfs_cleanup(void)
1573 {
1574         ENTER();
1575
1576         pr_info("unloading\n");
1577         unregister_filesystem(&ffs_fs_type);
1578 }
1579
1580
1581 /* ffs_data and ffs_function construction and destruction code **************/
1582
1583 static void ffs_data_clear(struct ffs_data *ffs);
1584 static void ffs_data_reset(struct ffs_data *ffs);
1585
1586 static void ffs_data_get(struct ffs_data *ffs)
1587 {
1588         ENTER();
1589
1590         refcount_inc(&ffs->ref);
1591 }
1592
1593 static void ffs_data_opened(struct ffs_data *ffs)
1594 {
1595         ENTER();
1596
1597         refcount_inc(&ffs->ref);
1598         if (atomic_add_return(1, &ffs->opened) == 1 &&
1599                         ffs->state == FFS_DEACTIVATED) {
1600                 ffs->state = FFS_CLOSING;
1601                 ffs_data_reset(ffs);
1602         }
1603 }
1604
1605 static void ffs_data_put(struct ffs_data *ffs)
1606 {
1607         ENTER();
1608
1609         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1610                 pr_info("%s(): freeing\n", __func__);
1611                 ffs_data_clear(ffs);
1612                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1613                        waitqueue_active(&ffs->ep0req_completion.wait) ||
1614                        waitqueue_active(&ffs->wait));
1615                 destroy_workqueue(ffs->io_completion_wq);
1616                 kfree(ffs->dev_name);
1617                 kfree(ffs);
1618         }
1619 }
1620
1621 static void ffs_data_closed(struct ffs_data *ffs)
1622 {
1623         ENTER();
1624
1625         if (atomic_dec_and_test(&ffs->opened)) {
1626                 if (ffs->no_disconnect) {
1627                         ffs->state = FFS_DEACTIVATED;
1628                         if (ffs->epfiles) {
1629                                 ffs_epfiles_destroy(ffs->epfiles,
1630                                                    ffs->eps_count);
1631                                 ffs->epfiles = NULL;
1632                         }
1633                         if (ffs->setup_state == FFS_SETUP_PENDING)
1634                                 __ffs_ep0_stall(ffs);
1635                 } else {
1636                         ffs->state = FFS_CLOSING;
1637                         ffs_data_reset(ffs);
1638                 }
1639         }
1640         if (atomic_read(&ffs->opened) < 0) {
1641                 ffs->state = FFS_CLOSING;
1642                 ffs_data_reset(ffs);
1643         }
1644
1645         ffs_data_put(ffs);
1646 }
1647
1648 static struct ffs_data *ffs_data_new(const char *dev_name)
1649 {
1650         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1651         if (unlikely(!ffs))
1652                 return NULL;
1653
1654         ENTER();
1655
1656         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1657         if (!ffs->io_completion_wq) {
1658                 kfree(ffs);
1659                 return NULL;
1660         }
1661
1662         refcount_set(&ffs->ref, 1);
1663         atomic_set(&ffs->opened, 0);
1664         ffs->state = FFS_READ_DESCRIPTORS;
1665         mutex_init(&ffs->mutex);
1666         spin_lock_init(&ffs->eps_lock);
1667         init_waitqueue_head(&ffs->ev.waitq);
1668         init_waitqueue_head(&ffs->wait);
1669         init_completion(&ffs->ep0req_completion);
1670
1671         /* XXX REVISIT need to update it in some places, or do we? */
1672         ffs->ev.can_stall = 1;
1673
1674         return ffs;
1675 }
1676
1677 static void ffs_data_clear(struct ffs_data *ffs)
1678 {
1679         ENTER();
1680
1681         ffs_closed(ffs);
1682
1683         BUG_ON(ffs->gadget);
1684
1685         if (ffs->epfiles)
1686                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1687
1688         if (ffs->ffs_eventfd)
1689                 eventfd_ctx_put(ffs->ffs_eventfd);
1690
1691         kfree(ffs->raw_descs_data);
1692         kfree(ffs->raw_strings);
1693         kfree(ffs->stringtabs);
1694 }
1695
1696 static void ffs_data_reset(struct ffs_data *ffs)
1697 {
1698         ENTER();
1699
1700         ffs_data_clear(ffs);
1701
1702         ffs->epfiles = NULL;
1703         ffs->raw_descs_data = NULL;
1704         ffs->raw_descs = NULL;
1705         ffs->raw_strings = NULL;
1706         ffs->stringtabs = NULL;
1707
1708         ffs->raw_descs_length = 0;
1709         ffs->fs_descs_count = 0;
1710         ffs->hs_descs_count = 0;
1711         ffs->ss_descs_count = 0;
1712
1713         ffs->strings_count = 0;
1714         ffs->interfaces_count = 0;
1715         ffs->eps_count = 0;
1716
1717         ffs->ev.count = 0;
1718
1719         ffs->state = FFS_READ_DESCRIPTORS;
1720         ffs->setup_state = FFS_NO_SETUP;
1721         ffs->flags = 0;
1722 }
1723
1724
1725 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1726 {
1727         struct usb_gadget_strings **lang;
1728         int first_id;
1729
1730         ENTER();
1731
1732         if (WARN_ON(ffs->state != FFS_ACTIVE
1733                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1734                 return -EBADFD;
1735
1736         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1737         if (unlikely(first_id < 0))
1738                 return first_id;
1739
1740         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1741         if (unlikely(!ffs->ep0req))
1742                 return -ENOMEM;
1743         ffs->ep0req->complete = ffs_ep0_complete;
1744         ffs->ep0req->context = ffs;
1745
1746         lang = ffs->stringtabs;
1747         if (lang) {
1748                 for (; *lang; ++lang) {
1749                         struct usb_string *str = (*lang)->strings;
1750                         int id = first_id;
1751                         for (; str->s; ++id, ++str)
1752                                 str->id = id;
1753                 }
1754         }
1755
1756         ffs->gadget = cdev->gadget;
1757         ffs_data_get(ffs);
1758         return 0;
1759 }
1760
1761 static void functionfs_unbind(struct ffs_data *ffs)
1762 {
1763         ENTER();
1764
1765         if (!WARN_ON(!ffs->gadget)) {
1766                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1767                 ffs->ep0req = NULL;
1768                 ffs->gadget = NULL;
1769                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1770                 ffs_data_put(ffs);
1771         }
1772 }
1773
1774 static int ffs_epfiles_create(struct ffs_data *ffs)
1775 {
1776         struct ffs_epfile *epfile, *epfiles;
1777         unsigned i, count;
1778
1779         ENTER();
1780
1781         count = ffs->eps_count;
1782         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1783         if (!epfiles)
1784                 return -ENOMEM;
1785
1786         epfile = epfiles;
1787         for (i = 1; i <= count; ++i, ++epfile) {
1788                 epfile->ffs = ffs;
1789                 mutex_init(&epfile->mutex);
1790                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1791                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1792                 else
1793                         sprintf(epfile->name, "ep%u", i);
1794                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1795                                                  epfile,
1796                                                  &ffs_epfile_operations);
1797                 if (unlikely(!epfile->dentry)) {
1798                         ffs_epfiles_destroy(epfiles, i - 1);
1799                         return -ENOMEM;
1800                 }
1801         }
1802
1803         ffs->epfiles = epfiles;
1804         return 0;
1805 }
1806
1807 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1808 {
1809         struct ffs_epfile *epfile = epfiles;
1810
1811         ENTER();
1812
1813         for (; count; --count, ++epfile) {
1814                 BUG_ON(mutex_is_locked(&epfile->mutex));
1815                 if (epfile->dentry) {
1816                         d_delete(epfile->dentry);
1817                         dput(epfile->dentry);
1818                         epfile->dentry = NULL;
1819                 }
1820         }
1821
1822         kfree(epfiles);
1823 }
1824
1825 static void ffs_func_eps_disable(struct ffs_function *func)
1826 {
1827         struct ffs_ep *ep         = func->eps;
1828         struct ffs_epfile *epfile = func->ffs->epfiles;
1829         unsigned count            = func->ffs->eps_count;
1830         unsigned long flags;
1831
1832         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1833         while (count--) {
1834                 /* pending requests get nuked */
1835                 if (likely(ep->ep))
1836                         usb_ep_disable(ep->ep);
1837                 ++ep;
1838
1839                 if (epfile) {
1840                         epfile->ep = NULL;
1841                         __ffs_epfile_read_buffer_free(epfile);
1842                         ++epfile;
1843                 }
1844         }
1845         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1846 }
1847
1848 static int ffs_func_eps_enable(struct ffs_function *func)
1849 {
1850         struct ffs_data *ffs      = func->ffs;
1851         struct ffs_ep *ep         = func->eps;
1852         struct ffs_epfile *epfile = ffs->epfiles;
1853         unsigned count            = ffs->eps_count;
1854         unsigned long flags;
1855         int ret = 0;
1856
1857         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1858         while(count--) {
1859                 struct usb_endpoint_descriptor *ds;
1860                 struct usb_ss_ep_comp_descriptor *comp_desc = NULL;
1861                 int needs_comp_desc = false;
1862                 int desc_idx;
1863
1864                 if (ffs->gadget->speed == USB_SPEED_SUPER) {
1865                         desc_idx = 2;
1866                         needs_comp_desc = true;
1867                 } else if (ffs->gadget->speed == USB_SPEED_HIGH)
1868                         desc_idx = 1;
1869                 else
1870                         desc_idx = 0;
1871
1872                 /* fall-back to lower speed if desc missing for current speed */
1873                 do {
1874                         ds = ep->descs[desc_idx];
1875                 } while (!ds && --desc_idx >= 0);
1876
1877                 if (!ds) {
1878                         ret = -EINVAL;
1879                         break;
1880                 }
1881
1882                 ep->ep->driver_data = ep;
1883                 ep->ep->desc = ds;
1884
1885                 if (needs_comp_desc) {
1886                         comp_desc = (struct usb_ss_ep_comp_descriptor *)(ds +
1887                                         USB_DT_ENDPOINT_SIZE);
1888                         ep->ep->maxburst = comp_desc->bMaxBurst + 1;
1889                         ep->ep->comp_desc = comp_desc;
1890                 }
1891
1892                 ret = usb_ep_enable(ep->ep);
1893                 if (likely(!ret)) {
1894                         epfile->ep = ep;
1895                         epfile->in = usb_endpoint_dir_in(ds);
1896                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1897                 } else {
1898                         break;
1899                 }
1900
1901                 ++ep;
1902                 ++epfile;
1903         }
1904
1905         wake_up_interruptible(&ffs->wait);
1906         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1907
1908         return ret;
1909 }
1910
1911
1912 /* Parsing and building descriptors and strings *****************************/
1913
1914 /*
1915  * This validates if data pointed by data is a valid USB descriptor as
1916  * well as record how many interfaces, endpoints and strings are
1917  * required by given configuration.  Returns address after the
1918  * descriptor or NULL if data is invalid.
1919  */
1920
1921 enum ffs_entity_type {
1922         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1923 };
1924
1925 enum ffs_os_desc_type {
1926         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1927 };
1928
1929 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1930                                    u8 *valuep,
1931                                    struct usb_descriptor_header *desc,
1932                                    void *priv);
1933
1934 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1935                                     struct usb_os_desc_header *h, void *data,
1936                                     unsigned len, void *priv);
1937
1938 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1939                                            ffs_entity_callback entity,
1940                                            void *priv)
1941 {
1942         struct usb_descriptor_header *_ds = (void *)data;
1943         u8 length;
1944         int ret;
1945
1946         ENTER();
1947
1948         /* At least two bytes are required: length and type */
1949         if (len < 2) {
1950                 pr_vdebug("descriptor too short\n");
1951                 return -EINVAL;
1952         }
1953
1954         /* If we have at least as many bytes as the descriptor takes? */
1955         length = _ds->bLength;
1956         if (len < length) {
1957                 pr_vdebug("descriptor longer then available data\n");
1958                 return -EINVAL;
1959         }
1960
1961 #define __entity_check_INTERFACE(val)  1
1962 #define __entity_check_STRING(val)     (val)
1963 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1964 #define __entity(type, val) do {                                        \
1965                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1966                 if (unlikely(!__entity_check_ ##type(val))) {           \
1967                         pr_vdebug("invalid entity's value\n");          \
1968                         return -EINVAL;                                 \
1969                 }                                                       \
1970                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1971                 if (unlikely(ret < 0)) {                                \
1972                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1973                                  (val), ret);                           \
1974                         return ret;                                     \
1975                 }                                                       \
1976         } while (0)
1977
1978         /* Parse descriptor depending on type. */
1979         switch (_ds->bDescriptorType) {
1980         case USB_DT_DEVICE:
1981         case USB_DT_CONFIG:
1982         case USB_DT_STRING:
1983         case USB_DT_DEVICE_QUALIFIER:
1984                 /* function can't have any of those */
1985                 pr_vdebug("descriptor reserved for gadget: %d\n",
1986                       _ds->bDescriptorType);
1987                 return -EINVAL;
1988
1989         case USB_DT_INTERFACE: {
1990                 struct usb_interface_descriptor *ds = (void *)_ds;
1991                 pr_vdebug("interface descriptor\n");
1992                 if (length != sizeof *ds)
1993                         goto inv_length;
1994
1995                 __entity(INTERFACE, ds->bInterfaceNumber);
1996                 if (ds->iInterface)
1997                         __entity(STRING, ds->iInterface);
1998         }
1999                 break;
2000
2001         case USB_DT_ENDPOINT: {
2002                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2003                 pr_vdebug("endpoint descriptor\n");
2004                 if (length != USB_DT_ENDPOINT_SIZE &&
2005                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2006                         goto inv_length;
2007                 __entity(ENDPOINT, ds->bEndpointAddress);
2008         }
2009                 break;
2010
2011         case HID_DT_HID:
2012                 pr_vdebug("hid descriptor\n");
2013                 if (length != sizeof(struct hid_descriptor))
2014                         goto inv_length;
2015                 break;
2016
2017         case USB_DT_OTG:
2018                 if (length != sizeof(struct usb_otg_descriptor))
2019                         goto inv_length;
2020                 break;
2021
2022         case USB_DT_INTERFACE_ASSOCIATION: {
2023                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2024                 pr_vdebug("interface association descriptor\n");
2025                 if (length != sizeof *ds)
2026                         goto inv_length;
2027                 if (ds->iFunction)
2028                         __entity(STRING, ds->iFunction);
2029         }
2030                 break;
2031
2032         case USB_DT_SS_ENDPOINT_COMP:
2033                 pr_vdebug("EP SS companion descriptor\n");
2034                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2035                         goto inv_length;
2036                 break;
2037
2038         case USB_DT_OTHER_SPEED_CONFIG:
2039         case USB_DT_INTERFACE_POWER:
2040         case USB_DT_DEBUG:
2041         case USB_DT_SECURITY:
2042         case USB_DT_CS_RADIO_CONTROL:
2043                 /* TODO */
2044                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2045                 return -EINVAL;
2046
2047         default:
2048                 /* We should never be here */
2049                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2050                 return -EINVAL;
2051
2052 inv_length:
2053                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2054                           _ds->bLength, _ds->bDescriptorType);
2055                 return -EINVAL;
2056         }
2057
2058 #undef __entity
2059 #undef __entity_check_DESCRIPTOR
2060 #undef __entity_check_INTERFACE
2061 #undef __entity_check_STRING
2062 #undef __entity_check_ENDPOINT
2063
2064         return length;
2065 }
2066
2067 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2068                                      ffs_entity_callback entity, void *priv)
2069 {
2070         const unsigned _len = len;
2071         unsigned long num = 0;
2072
2073         ENTER();
2074
2075         for (;;) {
2076                 int ret;
2077
2078                 if (num == count)
2079                         data = NULL;
2080
2081                 /* Record "descriptor" entity */
2082                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2083                 if (unlikely(ret < 0)) {
2084                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2085                                  num, ret);
2086                         return ret;
2087                 }
2088
2089                 if (!data)
2090                         return _len - len;
2091
2092                 ret = ffs_do_single_desc(data, len, entity, priv);
2093                 if (unlikely(ret < 0)) {
2094                         pr_debug("%s returns %d\n", __func__, ret);
2095                         return ret;
2096                 }
2097
2098                 len -= ret;
2099                 data += ret;
2100                 ++num;
2101         }
2102 }
2103
2104 static int __ffs_data_do_entity(enum ffs_entity_type type,
2105                                 u8 *valuep, struct usb_descriptor_header *desc,
2106                                 void *priv)
2107 {
2108         struct ffs_desc_helper *helper = priv;
2109         struct usb_endpoint_descriptor *d;
2110
2111         ENTER();
2112
2113         switch (type) {
2114         case FFS_DESCRIPTOR:
2115                 break;
2116
2117         case FFS_INTERFACE:
2118                 /*
2119                  * Interfaces are indexed from zero so if we
2120                  * encountered interface "n" then there are at least
2121                  * "n+1" interfaces.
2122                  */
2123                 if (*valuep >= helper->interfaces_count)
2124                         helper->interfaces_count = *valuep + 1;
2125                 break;
2126
2127         case FFS_STRING:
2128                 /*
2129                  * Strings are indexed from 1 (0 is reserved
2130                  * for languages list)
2131                  */
2132                 if (*valuep > helper->ffs->strings_count)
2133                         helper->ffs->strings_count = *valuep;
2134                 break;
2135
2136         case FFS_ENDPOINT:
2137                 d = (void *)desc;
2138                 helper->eps_count++;
2139                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2140                         return -EINVAL;
2141                 /* Check if descriptors for any speed were already parsed */
2142                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2143                         helper->ffs->eps_addrmap[helper->eps_count] =
2144                                 d->bEndpointAddress;
2145                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2146                                 d->bEndpointAddress)
2147                         return -EINVAL;
2148                 break;
2149         }
2150
2151         return 0;
2152 }
2153
2154 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2155                                    struct usb_os_desc_header *desc)
2156 {
2157         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2158         u16 w_index = le16_to_cpu(desc->wIndex);
2159
2160         if (bcd_version != 1) {
2161                 pr_vdebug("unsupported os descriptors version: %d",
2162                           bcd_version);
2163                 return -EINVAL;
2164         }
2165         switch (w_index) {
2166         case 0x4:
2167                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2168                 break;
2169         case 0x5:
2170                 *next_type = FFS_OS_DESC_EXT_PROP;
2171                 break;
2172         default:
2173                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2174                 return -EINVAL;
2175         }
2176
2177         return sizeof(*desc);
2178 }
2179
2180 /*
2181  * Process all extended compatibility/extended property descriptors
2182  * of a feature descriptor
2183  */
2184 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2185                                               enum ffs_os_desc_type type,
2186                                               u16 feature_count,
2187                                               ffs_os_desc_callback entity,
2188                                               void *priv,
2189                                               struct usb_os_desc_header *h)
2190 {
2191         int ret;
2192         const unsigned _len = len;
2193
2194         ENTER();
2195
2196         /* loop over all ext compat/ext prop descriptors */
2197         while (feature_count--) {
2198                 ret = entity(type, h, data, len, priv);
2199                 if (unlikely(ret < 0)) {
2200                         pr_debug("bad OS descriptor, type: %d\n", type);
2201                         return ret;
2202                 }
2203                 data += ret;
2204                 len -= ret;
2205         }
2206         return _len - len;
2207 }
2208
2209 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2210 static int __must_check ffs_do_os_descs(unsigned count,
2211                                         char *data, unsigned len,
2212                                         ffs_os_desc_callback entity, void *priv)
2213 {
2214         const unsigned _len = len;
2215         unsigned long num = 0;
2216
2217         ENTER();
2218
2219         for (num = 0; num < count; ++num) {
2220                 int ret;
2221                 enum ffs_os_desc_type type;
2222                 u16 feature_count;
2223                 struct usb_os_desc_header *desc = (void *)data;
2224
2225                 if (len < sizeof(*desc))
2226                         return -EINVAL;
2227
2228                 /*
2229                  * Record "descriptor" entity.
2230                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2231                  * Move the data pointer to the beginning of extended
2232                  * compatibilities proper or extended properties proper
2233                  * portions of the data
2234                  */
2235                 if (le32_to_cpu(desc->dwLength) > len)
2236                         return -EINVAL;
2237
2238                 ret = __ffs_do_os_desc_header(&type, desc);
2239                 if (unlikely(ret < 0)) {
2240                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2241                                  num, ret);
2242                         return ret;
2243                 }
2244                 /*
2245                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2246                  */
2247                 feature_count = le16_to_cpu(desc->wCount);
2248                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2249                     (feature_count > 255 || desc->Reserved))
2250                                 return -EINVAL;
2251                 len -= ret;
2252                 data += ret;
2253
2254                 /*
2255                  * Process all function/property descriptors
2256                  * of this Feature Descriptor
2257                  */
2258                 ret = ffs_do_single_os_desc(data, len, type,
2259                                             feature_count, entity, priv, desc);
2260                 if (unlikely(ret < 0)) {
2261                         pr_debug("%s returns %d\n", __func__, ret);
2262                         return ret;
2263                 }
2264
2265                 len -= ret;
2266                 data += ret;
2267         }
2268         return _len - len;
2269 }
2270
2271 /**
2272  * Validate contents of the buffer from userspace related to OS descriptors.
2273  */
2274 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2275                                  struct usb_os_desc_header *h, void *data,
2276                                  unsigned len, void *priv)
2277 {
2278         struct ffs_data *ffs = priv;
2279         u8 length;
2280
2281         ENTER();
2282
2283         switch (type) {
2284         case FFS_OS_DESC_EXT_COMPAT: {
2285                 struct usb_ext_compat_desc *d = data;
2286                 int i;
2287
2288                 if (len < sizeof(*d) ||
2289                     d->bFirstInterfaceNumber >= ffs->interfaces_count ||
2290                     !d->Reserved1)
2291                         return -EINVAL;
2292                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2293                         if (d->Reserved2[i])
2294                                 return -EINVAL;
2295
2296                 length = sizeof(struct usb_ext_compat_desc);
2297         }
2298                 break;
2299         case FFS_OS_DESC_EXT_PROP: {
2300                 struct usb_ext_prop_desc *d = data;
2301                 u32 type, pdl;
2302                 u16 pnl;
2303
2304                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2305                         return -EINVAL;
2306                 length = le32_to_cpu(d->dwSize);
2307                 if (len < length)
2308                         return -EINVAL;
2309                 type = le32_to_cpu(d->dwPropertyDataType);
2310                 if (type < USB_EXT_PROP_UNICODE ||
2311                     type > USB_EXT_PROP_UNICODE_MULTI) {
2312                         pr_vdebug("unsupported os descriptor property type: %d",
2313                                   type);
2314                         return -EINVAL;
2315                 }
2316                 pnl = le16_to_cpu(d->wPropertyNameLength);
2317                 if (length < 14 + pnl) {
2318                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2319                                   length, pnl, type);
2320                         return -EINVAL;
2321                 }
2322                 pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
2323                 if (length != 14 + pnl + pdl) {
2324                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2325                                   length, pnl, pdl, type);
2326                         return -EINVAL;
2327                 }
2328                 ++ffs->ms_os_descs_ext_prop_count;
2329                 /* property name reported to the host as "WCHAR"s */
2330                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2331                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2332         }
2333                 break;
2334         default:
2335                 pr_vdebug("unknown descriptor: %d\n", type);
2336                 return -EINVAL;
2337         }
2338         return length;
2339 }
2340
2341 static int __ffs_data_got_descs(struct ffs_data *ffs,
2342                                 char *const _data, size_t len)
2343 {
2344         char *data = _data, *raw_descs;
2345         unsigned os_descs_count = 0, counts[3], flags;
2346         int ret = -EINVAL, i;
2347         struct ffs_desc_helper helper;
2348
2349         ENTER();
2350
2351         if (get_unaligned_le32(data + 4) != len)
2352                 goto error;
2353
2354         switch (get_unaligned_le32(data)) {
2355         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2356                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2357                 data += 8;
2358                 len  -= 8;
2359                 break;
2360         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2361                 flags = get_unaligned_le32(data + 8);
2362                 ffs->user_flags = flags;
2363                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2364                               FUNCTIONFS_HAS_HS_DESC |
2365                               FUNCTIONFS_HAS_SS_DESC |
2366                               FUNCTIONFS_HAS_MS_OS_DESC |
2367                               FUNCTIONFS_VIRTUAL_ADDR |
2368                               FUNCTIONFS_EVENTFD |
2369                               FUNCTIONFS_ALL_CTRL_RECIP |
2370                               FUNCTIONFS_CONFIG0_SETUP)) {
2371                         ret = -ENOSYS;
2372                         goto error;
2373                 }
2374                 data += 12;
2375                 len  -= 12;
2376                 break;
2377         default:
2378                 goto error;
2379         }
2380
2381         if (flags & FUNCTIONFS_EVENTFD) {
2382                 if (len < 4)
2383                         goto error;
2384                 ffs->ffs_eventfd =
2385                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2386                 if (IS_ERR(ffs->ffs_eventfd)) {
2387                         ret = PTR_ERR(ffs->ffs_eventfd);
2388                         ffs->ffs_eventfd = NULL;
2389                         goto error;
2390                 }
2391                 data += 4;
2392                 len  -= 4;
2393         }
2394
2395         /* Read fs_count, hs_count and ss_count (if present) */
2396         for (i = 0; i < 3; ++i) {
2397                 if (!(flags & (1 << i))) {
2398                         counts[i] = 0;
2399                 } else if (len < 4) {
2400                         goto error;
2401                 } else {
2402                         counts[i] = get_unaligned_le32(data);
2403                         data += 4;
2404                         len  -= 4;
2405                 }
2406         }
2407         if (flags & (1 << i)) {
2408                 if (len < 4) {
2409                         goto error;
2410                 }
2411                 os_descs_count = get_unaligned_le32(data);
2412                 data += 4;
2413                 len -= 4;
2414         };
2415
2416         /* Read descriptors */
2417         raw_descs = data;
2418         helper.ffs = ffs;
2419         for (i = 0; i < 3; ++i) {
2420                 if (!counts[i])
2421                         continue;
2422                 helper.interfaces_count = 0;
2423                 helper.eps_count = 0;
2424                 ret = ffs_do_descs(counts[i], data, len,
2425                                    __ffs_data_do_entity, &helper);
2426                 if (ret < 0)
2427                         goto error;
2428                 if (!ffs->eps_count && !ffs->interfaces_count) {
2429                         ffs->eps_count = helper.eps_count;
2430                         ffs->interfaces_count = helper.interfaces_count;
2431                 } else {
2432                         if (ffs->eps_count != helper.eps_count) {
2433                                 ret = -EINVAL;
2434                                 goto error;
2435                         }
2436                         if (ffs->interfaces_count != helper.interfaces_count) {
2437                                 ret = -EINVAL;
2438                                 goto error;
2439                         }
2440                 }
2441                 data += ret;
2442                 len  -= ret;
2443         }
2444         if (os_descs_count) {
2445                 ret = ffs_do_os_descs(os_descs_count, data, len,
2446                                       __ffs_data_do_os_desc, ffs);
2447                 if (ret < 0)
2448                         goto error;
2449                 data += ret;
2450                 len -= ret;
2451         }
2452
2453         if (raw_descs == data || len) {
2454                 ret = -EINVAL;
2455                 goto error;
2456         }
2457
2458         ffs->raw_descs_data     = _data;
2459         ffs->raw_descs          = raw_descs;
2460         ffs->raw_descs_length   = data - raw_descs;
2461         ffs->fs_descs_count     = counts[0];
2462         ffs->hs_descs_count     = counts[1];
2463         ffs->ss_descs_count     = counts[2];
2464         ffs->ms_os_descs_count  = os_descs_count;
2465
2466         return 0;
2467
2468 error:
2469         kfree(_data);
2470         return ret;
2471 }
2472
2473 static int __ffs_data_got_strings(struct ffs_data *ffs,
2474                                   char *const _data, size_t len)
2475 {
2476         u32 str_count, needed_count, lang_count;
2477         struct usb_gadget_strings **stringtabs, *t;
2478         const char *data = _data;
2479         struct usb_string *s;
2480
2481         ENTER();
2482
2483         if (unlikely(len < 16 ||
2484                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2485                      get_unaligned_le32(data + 4) != len))
2486                 goto error;
2487         str_count  = get_unaligned_le32(data + 8);
2488         lang_count = get_unaligned_le32(data + 12);
2489
2490         /* if one is zero the other must be zero */
2491         if (unlikely(!str_count != !lang_count))
2492                 goto error;
2493
2494         /* Do we have at least as many strings as descriptors need? */
2495         needed_count = ffs->strings_count;
2496         if (unlikely(str_count < needed_count))
2497                 goto error;
2498
2499         /*
2500          * If we don't need any strings just return and free all
2501          * memory.
2502          */
2503         if (!needed_count) {
2504                 kfree(_data);
2505                 return 0;
2506         }
2507
2508         /* Allocate everything in one chunk so there's less maintenance. */
2509         {
2510                 unsigned i = 0;
2511                 vla_group(d);
2512                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2513                         lang_count + 1);
2514                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2515                 vla_item(d, struct usb_string, strings,
2516                         lang_count*(needed_count+1));
2517
2518                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2519
2520                 if (unlikely(!vlabuf)) {
2521                         kfree(_data);
2522                         return -ENOMEM;
2523                 }
2524
2525                 /* Initialize the VLA pointers */
2526                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2527                 t = vla_ptr(vlabuf, d, stringtab);
2528                 i = lang_count;
2529                 do {
2530                         *stringtabs++ = t++;
2531                 } while (--i);
2532                 *stringtabs = NULL;
2533
2534                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2535                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2536                 t = vla_ptr(vlabuf, d, stringtab);
2537                 s = vla_ptr(vlabuf, d, strings);
2538         }
2539
2540         /* For each language */
2541         data += 16;
2542         len -= 16;
2543
2544         do { /* lang_count > 0 so we can use do-while */
2545                 unsigned needed = needed_count;
2546
2547                 if (unlikely(len < 3))
2548                         goto error_free;
2549                 t->language = get_unaligned_le16(data);
2550                 t->strings  = s;
2551                 ++t;
2552
2553                 data += 2;
2554                 len -= 2;
2555
2556                 /* For each string */
2557                 do { /* str_count > 0 so we can use do-while */
2558                         size_t length = strnlen(data, len);
2559
2560                         if (unlikely(length == len))
2561                                 goto error_free;
2562
2563                         /*
2564                          * User may provide more strings then we need,
2565                          * if that's the case we simply ignore the
2566                          * rest
2567                          */
2568                         if (likely(needed)) {
2569                                 /*
2570                                  * s->id will be set while adding
2571                                  * function to configuration so for
2572                                  * now just leave garbage here.
2573                                  */
2574                                 s->s = data;
2575                                 --needed;
2576                                 ++s;
2577                         }
2578
2579                         data += length + 1;
2580                         len -= length + 1;
2581                 } while (--str_count);
2582
2583                 s->id = 0;   /* terminator */
2584                 s->s = NULL;
2585                 ++s;
2586
2587         } while (--lang_count);
2588
2589         /* Some garbage left? */
2590         if (unlikely(len))
2591                 goto error_free;
2592
2593         /* Done! */
2594         ffs->stringtabs = stringtabs;
2595         ffs->raw_strings = _data;
2596
2597         return 0;
2598
2599 error_free:
2600         kfree(stringtabs);
2601 error:
2602         kfree(_data);
2603         return -EINVAL;
2604 }
2605
2606
2607 /* Events handling and management *******************************************/
2608
2609 static void __ffs_event_add(struct ffs_data *ffs,
2610                             enum usb_functionfs_event_type type)
2611 {
2612         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2613         int neg = 0;
2614
2615         /*
2616          * Abort any unhandled setup
2617          *
2618          * We do not need to worry about some cmpxchg() changing value
2619          * of ffs->setup_state without holding the lock because when
2620          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2621          * the source does nothing.
2622          */
2623         if (ffs->setup_state == FFS_SETUP_PENDING)
2624                 ffs->setup_state = FFS_SETUP_CANCELLED;
2625
2626         /*
2627          * Logic of this function guarantees that there are at most four pending
2628          * evens on ffs->ev.types queue.  This is important because the queue
2629          * has space for four elements only and __ffs_ep0_read_events function
2630          * depends on that limit as well.  If more event types are added, those
2631          * limits have to be revisited or guaranteed to still hold.
2632          */
2633         switch (type) {
2634         case FUNCTIONFS_RESUME:
2635                 rem_type2 = FUNCTIONFS_SUSPEND;
2636                 /* FALL THROUGH */
2637         case FUNCTIONFS_SUSPEND:
2638         case FUNCTIONFS_SETUP:
2639                 rem_type1 = type;
2640                 /* Discard all similar events */
2641                 break;
2642
2643         case FUNCTIONFS_BIND:
2644         case FUNCTIONFS_UNBIND:
2645         case FUNCTIONFS_DISABLE:
2646         case FUNCTIONFS_ENABLE:
2647                 /* Discard everything other then power management. */
2648                 rem_type1 = FUNCTIONFS_SUSPEND;
2649                 rem_type2 = FUNCTIONFS_RESUME;
2650                 neg = 1;
2651                 break;
2652
2653         default:
2654                 WARN(1, "%d: unknown event, this should not happen\n", type);
2655                 return;
2656         }
2657
2658         {
2659                 u8 *ev  = ffs->ev.types, *out = ev;
2660                 unsigned n = ffs->ev.count;
2661                 for (; n; --n, ++ev)
2662                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2663                                 *out++ = *ev;
2664                         else
2665                                 pr_vdebug("purging event %d\n", *ev);
2666                 ffs->ev.count = out - ffs->ev.types;
2667         }
2668
2669         pr_vdebug("adding event %d\n", type);
2670         ffs->ev.types[ffs->ev.count++] = type;
2671         wake_up_locked(&ffs->ev.waitq);
2672         if (ffs->ffs_eventfd)
2673                 eventfd_signal(ffs->ffs_eventfd, 1);
2674 }
2675
2676 static void ffs_event_add(struct ffs_data *ffs,
2677                           enum usb_functionfs_event_type type)
2678 {
2679         unsigned long flags;
2680         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2681         __ffs_event_add(ffs, type);
2682         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2683 }
2684
2685 /* Bind/unbind USB function hooks *******************************************/
2686
2687 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2688 {
2689         int i;
2690
2691         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2692                 if (ffs->eps_addrmap[i] == endpoint_address)
2693                         return i;
2694         return -ENOENT;
2695 }
2696
2697 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2698                                     struct usb_descriptor_header *desc,
2699                                     void *priv)
2700 {
2701         struct usb_endpoint_descriptor *ds = (void *)desc;
2702         struct ffs_function *func = priv;
2703         struct ffs_ep *ffs_ep;
2704         unsigned ep_desc_id;
2705         int idx;
2706         static const char *speed_names[] = { "full", "high", "super" };
2707
2708         if (type != FFS_DESCRIPTOR)
2709                 return 0;
2710
2711         /*
2712          * If ss_descriptors is not NULL, we are reading super speed
2713          * descriptors; if hs_descriptors is not NULL, we are reading high
2714          * speed descriptors; otherwise, we are reading full speed
2715          * descriptors.
2716          */
2717         if (func->function.ss_descriptors) {
2718                 ep_desc_id = 2;
2719                 func->function.ss_descriptors[(long)valuep] = desc;
2720         } else if (func->function.hs_descriptors) {
2721                 ep_desc_id = 1;
2722                 func->function.hs_descriptors[(long)valuep] = desc;
2723         } else {
2724                 ep_desc_id = 0;
2725                 func->function.fs_descriptors[(long)valuep]    = desc;
2726         }
2727
2728         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2729                 return 0;
2730
2731         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2732         if (idx < 0)
2733                 return idx;
2734
2735         ffs_ep = func->eps + idx;
2736
2737         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2738                 pr_err("two %sspeed descriptors for EP %d\n",
2739                           speed_names[ep_desc_id],
2740                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2741                 return -EINVAL;
2742         }
2743         ffs_ep->descs[ep_desc_id] = ds;
2744
2745         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2746         if (ffs_ep->ep) {
2747                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2748                 if (!ds->wMaxPacketSize)
2749                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2750         } else {
2751                 struct usb_request *req;
2752                 struct usb_ep *ep;
2753                 u8 bEndpointAddress;
2754
2755                 /*
2756                  * We back up bEndpointAddress because autoconfig overwrites
2757                  * it with physical endpoint address.
2758                  */
2759                 bEndpointAddress = ds->bEndpointAddress;
2760                 pr_vdebug("autoconfig\n");
2761                 ep = usb_ep_autoconfig(func->gadget, ds);
2762                 if (unlikely(!ep))
2763                         return -ENOTSUPP;
2764                 ep->driver_data = func->eps + idx;
2765
2766                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2767                 if (unlikely(!req))
2768                         return -ENOMEM;
2769
2770                 ffs_ep->ep  = ep;
2771                 ffs_ep->req = req;
2772                 func->eps_revmap[ds->bEndpointAddress &
2773                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2774                 /*
2775                  * If we use virtual address mapping, we restore
2776                  * original bEndpointAddress value.
2777                  */
2778                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2779                         ds->bEndpointAddress = bEndpointAddress;
2780         }
2781         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2782
2783         return 0;
2784 }
2785
2786 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2787                                    struct usb_descriptor_header *desc,
2788                                    void *priv)
2789 {
2790         struct ffs_function *func = priv;
2791         unsigned idx;
2792         u8 newValue;
2793
2794         switch (type) {
2795         default:
2796         case FFS_DESCRIPTOR:
2797                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2798                 return 0;
2799
2800         case FFS_INTERFACE:
2801                 idx = *valuep;
2802                 if (func->interfaces_nums[idx] < 0) {
2803                         int id = usb_interface_id(func->conf, &func->function);
2804                         if (unlikely(id < 0))
2805                                 return id;
2806                         func->interfaces_nums[idx] = id;
2807                 }
2808                 newValue = func->interfaces_nums[idx];
2809                 break;
2810
2811         case FFS_STRING:
2812                 /* String' IDs are allocated when fsf_data is bound to cdev */
2813                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2814                 break;
2815
2816         case FFS_ENDPOINT:
2817                 /*
2818                  * USB_DT_ENDPOINT are handled in
2819                  * __ffs_func_bind_do_descs().
2820                  */
2821                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2822                         return 0;
2823
2824                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2825                 if (unlikely(!func->eps[idx].ep))
2826                         return -EINVAL;
2827
2828                 {
2829                         struct usb_endpoint_descriptor **descs;
2830                         descs = func->eps[idx].descs;
2831                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2832                 }
2833                 break;
2834         }
2835
2836         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2837         *valuep = newValue;
2838         return 0;
2839 }
2840
2841 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2842                                       struct usb_os_desc_header *h, void *data,
2843                                       unsigned len, void *priv)
2844 {
2845         struct ffs_function *func = priv;
2846         u8 length = 0;
2847
2848         switch (type) {
2849         case FFS_OS_DESC_EXT_COMPAT: {
2850                 struct usb_ext_compat_desc *desc = data;
2851                 struct usb_os_desc_table *t;
2852
2853                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2854                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2855                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2856                        ARRAY_SIZE(desc->CompatibleID) +
2857                        ARRAY_SIZE(desc->SubCompatibleID));
2858                 length = sizeof(*desc);
2859         }
2860                 break;
2861         case FFS_OS_DESC_EXT_PROP: {
2862                 struct usb_ext_prop_desc *desc = data;
2863                 struct usb_os_desc_table *t;
2864                 struct usb_os_desc_ext_prop *ext_prop;
2865                 char *ext_prop_name;
2866                 char *ext_prop_data;
2867
2868                 t = &func->function.os_desc_table[h->interface];
2869                 t->if_id = func->interfaces_nums[h->interface];
2870
2871                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2872                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2873
2874                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2875                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2876                 ext_prop->data_len = le32_to_cpu(*(u32 *)
2877                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2878                 length = ext_prop->name_len + ext_prop->data_len + 14;
2879
2880                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2881                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2882                         ext_prop->name_len;
2883
2884                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2885                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2886                         ext_prop->data_len;
2887                 memcpy(ext_prop_data,
2888                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2889                        ext_prop->data_len);
2890                 /* unicode data reported to the host as "WCHAR"s */
2891                 switch (ext_prop->type) {
2892                 case USB_EXT_PROP_UNICODE:
2893                 case USB_EXT_PROP_UNICODE_ENV:
2894                 case USB_EXT_PROP_UNICODE_LINK:
2895                 case USB_EXT_PROP_UNICODE_MULTI:
2896                         ext_prop->data_len *= 2;
2897                         break;
2898                 }
2899                 ext_prop->data = ext_prop_data;
2900
2901                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2902                        ext_prop->name_len);
2903                 /* property name reported to the host as "WCHAR"s */
2904                 ext_prop->name_len *= 2;
2905                 ext_prop->name = ext_prop_name;
2906
2907                 t->os_desc->ext_prop_len +=
2908                         ext_prop->name_len + ext_prop->data_len + 14;
2909                 ++t->os_desc->ext_prop_count;
2910                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2911         }
2912                 break;
2913         default:
2914                 pr_vdebug("unknown descriptor: %d\n", type);
2915         }
2916
2917         return length;
2918 }
2919
2920 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2921                                                 struct usb_configuration *c)
2922 {
2923         struct ffs_function *func = ffs_func_from_usb(f);
2924         struct f_fs_opts *ffs_opts =
2925                 container_of(f->fi, struct f_fs_opts, func_inst);
2926         int ret;
2927
2928         ENTER();
2929
2930         /*
2931          * Legacy gadget triggers binding in functionfs_ready_callback,
2932          * which already uses locking; taking the same lock here would
2933          * cause a deadlock.
2934          *
2935          * Configfs-enabled gadgets however do need ffs_dev_lock.
2936          */
2937         if (!ffs_opts->no_configfs)
2938                 ffs_dev_lock();
2939         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2940         func->ffs = ffs_opts->dev->ffs_data;
2941         if (!ffs_opts->no_configfs)
2942                 ffs_dev_unlock();
2943         if (ret)
2944                 return ERR_PTR(ret);
2945
2946         func->conf = c;
2947         func->gadget = c->cdev->gadget;
2948
2949         /*
2950          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2951          * configurations are bound in sequence with list_for_each_entry,
2952          * in each configuration its functions are bound in sequence
2953          * with list_for_each_entry, so we assume no race condition
2954          * with regard to ffs_opts->bound access
2955          */
2956         if (!ffs_opts->refcnt) {
2957                 ret = functionfs_bind(func->ffs, c->cdev);
2958                 if (ret)
2959                         return ERR_PTR(ret);
2960         }
2961         ffs_opts->refcnt++;
2962         func->function.strings = func->ffs->stringtabs;
2963
2964         return ffs_opts;
2965 }
2966
2967 static int _ffs_func_bind(struct usb_configuration *c,
2968                           struct usb_function *f)
2969 {
2970         struct ffs_function *func = ffs_func_from_usb(f);
2971         struct ffs_data *ffs = func->ffs;
2972
2973         const int full = !!func->ffs->fs_descs_count;
2974         const int high = gadget_is_dualspeed(func->gadget) &&
2975                 func->ffs->hs_descs_count;
2976         const int super = gadget_is_superspeed(func->gadget) &&
2977                 func->ffs->ss_descs_count;
2978
2979         int fs_len, hs_len, ss_len, ret, i;
2980         struct ffs_ep *eps_ptr;
2981
2982         /* Make it a single chunk, less management later on */
2983         vla_group(d);
2984         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2985         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2986                 full ? ffs->fs_descs_count + 1 : 0);
2987         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2988                 high ? ffs->hs_descs_count + 1 : 0);
2989         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2990                 super ? ffs->ss_descs_count + 1 : 0);
2991         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2992         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2993                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2994         vla_item_with_sz(d, char[16], ext_compat,
2995                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2996         vla_item_with_sz(d, struct usb_os_desc, os_desc,
2997                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2998         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
2999                          ffs->ms_os_descs_ext_prop_count);
3000         vla_item_with_sz(d, char, ext_prop_name,
3001                          ffs->ms_os_descs_ext_prop_name_len);
3002         vla_item_with_sz(d, char, ext_prop_data,
3003                          ffs->ms_os_descs_ext_prop_data_len);
3004         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3005         char *vlabuf;
3006
3007         ENTER();
3008
3009         /* Has descriptors only for speeds gadget does not support */
3010         if (unlikely(!(full | high | super)))
3011                 return -ENOTSUPP;
3012
3013         /* Allocate a single chunk, less management later on */
3014         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3015         if (unlikely(!vlabuf))
3016                 return -ENOMEM;
3017
3018         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3019         ffs->ms_os_descs_ext_prop_name_avail =
3020                 vla_ptr(vlabuf, d, ext_prop_name);
3021         ffs->ms_os_descs_ext_prop_data_avail =
3022                 vla_ptr(vlabuf, d, ext_prop_data);
3023
3024         /* Copy descriptors  */
3025         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3026                ffs->raw_descs_length);
3027
3028         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3029         eps_ptr = vla_ptr(vlabuf, d, eps);
3030         for (i = 0; i < ffs->eps_count; i++)
3031                 eps_ptr[i].num = -1;
3032
3033         /* Save pointers
3034          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3035         */
3036         func->eps             = vla_ptr(vlabuf, d, eps);
3037         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3038
3039         /*
3040          * Go through all the endpoint descriptors and allocate
3041          * endpoints first, so that later we can rewrite the endpoint
3042          * numbers without worrying that it may be described later on.
3043          */
3044         if (likely(full)) {
3045                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3046                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3047                                       vla_ptr(vlabuf, d, raw_descs),
3048                                       d_raw_descs__sz,
3049                                       __ffs_func_bind_do_descs, func);
3050                 if (unlikely(fs_len < 0)) {
3051                         ret = fs_len;
3052                         goto error;
3053                 }
3054         } else {
3055                 fs_len = 0;
3056         }
3057
3058         if (likely(high)) {
3059                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3060                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3061                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3062                                       d_raw_descs__sz - fs_len,
3063                                       __ffs_func_bind_do_descs, func);
3064                 if (unlikely(hs_len < 0)) {
3065                         ret = hs_len;
3066                         goto error;
3067                 }
3068         } else {
3069                 hs_len = 0;
3070         }
3071
3072         if (likely(super)) {
3073                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3074                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3075                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3076                                 d_raw_descs__sz - fs_len - hs_len,
3077                                 __ffs_func_bind_do_descs, func);
3078                 if (unlikely(ss_len < 0)) {
3079                         ret = ss_len;
3080                         goto error;
3081                 }
3082         } else {
3083                 ss_len = 0;
3084         }
3085
3086         /*
3087          * Now handle interface numbers allocation and interface and
3088          * endpoint numbers rewriting.  We can do that in one go
3089          * now.
3090          */
3091         ret = ffs_do_descs(ffs->fs_descs_count +
3092                            (high ? ffs->hs_descs_count : 0) +
3093                            (super ? ffs->ss_descs_count : 0),
3094                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3095                            __ffs_func_bind_do_nums, func);
3096         if (unlikely(ret < 0))
3097                 goto error;
3098
3099         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3100         if (c->cdev->use_os_string) {
3101                 for (i = 0; i < ffs->interfaces_count; ++i) {
3102                         struct usb_os_desc *desc;
3103
3104                         desc = func->function.os_desc_table[i].os_desc =
3105                                 vla_ptr(vlabuf, d, os_desc) +
3106                                 i * sizeof(struct usb_os_desc);
3107                         desc->ext_compat_id =
3108                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3109                         INIT_LIST_HEAD(&desc->ext_prop);
3110                 }
3111                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3112                                       vla_ptr(vlabuf, d, raw_descs) +
3113                                       fs_len + hs_len + ss_len,
3114                                       d_raw_descs__sz - fs_len - hs_len -
3115                                       ss_len,
3116                                       __ffs_func_bind_do_os_desc, func);
3117                 if (unlikely(ret < 0))
3118                         goto error;
3119         }
3120         func->function.os_desc_n =
3121                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3122
3123         /* And we're done */
3124         ffs_event_add(ffs, FUNCTIONFS_BIND);
3125         return 0;
3126
3127 error:
3128         /* XXX Do we need to release all claimed endpoints here? */
3129         return ret;
3130 }
3131
3132 static int ffs_func_bind(struct usb_configuration *c,
3133                          struct usb_function *f)
3134 {
3135         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3136         struct ffs_function *func = ffs_func_from_usb(f);
3137         int ret;
3138
3139         if (IS_ERR(ffs_opts))
3140                 return PTR_ERR(ffs_opts);
3141
3142         ret = _ffs_func_bind(c, f);
3143         if (ret && !--ffs_opts->refcnt)
3144                 functionfs_unbind(func->ffs);
3145
3146         return ret;
3147 }
3148
3149
3150 /* Other USB function hooks *************************************************/
3151
3152 static void ffs_reset_work(struct work_struct *work)
3153 {
3154         struct ffs_data *ffs = container_of(work,
3155                 struct ffs_data, reset_work);
3156         ffs_data_reset(ffs);
3157 }
3158
3159 static int ffs_func_set_alt(struct usb_function *f,
3160                             unsigned interface, unsigned alt)
3161 {
3162         struct ffs_function *func = ffs_func_from_usb(f);
3163         struct ffs_data *ffs = func->ffs;
3164         int ret = 0, intf;
3165
3166         if (alt != (unsigned)-1) {
3167                 intf = ffs_func_revmap_intf(func, interface);
3168                 if (unlikely(intf < 0))
3169                         return intf;
3170         }
3171
3172         if (ffs->func)
3173                 ffs_func_eps_disable(ffs->func);
3174
3175         if (ffs->state == FFS_DEACTIVATED) {
3176                 ffs->state = FFS_CLOSING;
3177                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3178                 schedule_work(&ffs->reset_work);
3179                 return -ENODEV;
3180         }
3181
3182         if (ffs->state != FFS_ACTIVE)
3183                 return -ENODEV;
3184
3185         if (alt == (unsigned)-1) {
3186                 ffs->func = NULL;
3187                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3188                 return 0;
3189         }
3190
3191         ffs->func = func;
3192         ret = ffs_func_eps_enable(func);
3193         if (likely(ret >= 0))
3194                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3195         return ret;
3196 }
3197
3198 static void ffs_func_disable(struct usb_function *f)
3199 {
3200         ffs_func_set_alt(f, 0, (unsigned)-1);
3201 }
3202
3203 static int ffs_func_setup(struct usb_function *f,
3204                           const struct usb_ctrlrequest *creq)
3205 {
3206         struct ffs_function *func = ffs_func_from_usb(f);
3207         struct ffs_data *ffs = func->ffs;
3208         unsigned long flags;
3209         int ret;
3210
3211         ENTER();
3212
3213         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3214         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3215         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3216         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3217         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3218
3219         /*
3220          * Most requests directed to interface go through here
3221          * (notable exceptions are set/get interface) so we need to
3222          * handle them.  All other either handled by composite or
3223          * passed to usb_configuration->setup() (if one is set).  No
3224          * matter, we will handle requests directed to endpoint here
3225          * as well (as it's straightforward).  Other request recipient
3226          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3227          * is being used.
3228          */
3229         if (ffs->state != FFS_ACTIVE)
3230                 return -ENODEV;
3231
3232         switch (creq->bRequestType & USB_RECIP_MASK) {
3233         case USB_RECIP_INTERFACE:
3234                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3235                 if (unlikely(ret < 0))
3236                         return ret;
3237                 break;
3238
3239         case USB_RECIP_ENDPOINT:
3240                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3241                 if (unlikely(ret < 0))
3242                         return ret;
3243                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3244                         ret = func->ffs->eps_addrmap[ret];
3245                 break;
3246
3247         default:
3248                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3249                         ret = le16_to_cpu(creq->wIndex);
3250                 else
3251                         return -EOPNOTSUPP;
3252         }
3253
3254         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3255         ffs->ev.setup = *creq;
3256         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3257         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3258         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3259
3260         return 0;
3261 }
3262
3263 static bool ffs_func_req_match(struct usb_function *f,
3264                                const struct usb_ctrlrequest *creq,
3265                                bool config0)
3266 {
3267         struct ffs_function *func = ffs_func_from_usb(f);
3268
3269         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3270                 return false;
3271
3272         switch (creq->bRequestType & USB_RECIP_MASK) {
3273         case USB_RECIP_INTERFACE:
3274                 return (ffs_func_revmap_intf(func,
3275                                              le16_to_cpu(creq->wIndex)) >= 0);
3276         case USB_RECIP_ENDPOINT:
3277                 return (ffs_func_revmap_ep(func,
3278                                            le16_to_cpu(creq->wIndex)) >= 0);
3279         default:
3280                 return (bool) (func->ffs->user_flags &
3281                                FUNCTIONFS_ALL_CTRL_RECIP);
3282         }
3283 }
3284
3285 static void ffs_func_suspend(struct usb_function *f)
3286 {
3287         ENTER();
3288         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3289 }
3290
3291 static void ffs_func_resume(struct usb_function *f)
3292 {
3293         ENTER();
3294         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3295 }
3296
3297
3298 /* Endpoint and interface numbers reverse mapping ***************************/
3299
3300 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3301 {
3302         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3303         return num ? num : -EDOM;
3304 }
3305
3306 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3307 {
3308         short *nums = func->interfaces_nums;
3309         unsigned count = func->ffs->interfaces_count;
3310
3311         for (; count; --count, ++nums) {
3312                 if (*nums >= 0 && *nums == intf)
3313                         return nums - func->interfaces_nums;
3314         }
3315
3316         return -EDOM;
3317 }
3318
3319
3320 /* Devices management *******************************************************/
3321
3322 static LIST_HEAD(ffs_devices);
3323
3324 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3325 {
3326         struct ffs_dev *dev;
3327
3328         if (!name)
3329                 return NULL;
3330
3331         list_for_each_entry(dev, &ffs_devices, entry) {
3332                 if (strcmp(dev->name, name) == 0)
3333                         return dev;
3334         }
3335
3336         return NULL;
3337 }
3338
3339 /*
3340  * ffs_lock must be taken by the caller of this function
3341  */
3342 static struct ffs_dev *_ffs_get_single_dev(void)
3343 {
3344         struct ffs_dev *dev;
3345
3346         if (list_is_singular(&ffs_devices)) {
3347                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3348                 if (dev->single)
3349                         return dev;
3350         }
3351
3352         return NULL;
3353 }
3354
3355 /*
3356  * ffs_lock must be taken by the caller of this function
3357  */
3358 static struct ffs_dev *_ffs_find_dev(const char *name)
3359 {
3360         struct ffs_dev *dev;
3361
3362         dev = _ffs_get_single_dev();
3363         if (dev)
3364                 return dev;
3365
3366         return _ffs_do_find_dev(name);
3367 }
3368
3369 /* Configfs support *********************************************************/
3370
3371 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3372 {
3373         return container_of(to_config_group(item), struct f_fs_opts,
3374                             func_inst.group);
3375 }
3376
3377 static void ffs_attr_release(struct config_item *item)
3378 {
3379         struct f_fs_opts *opts = to_ffs_opts(item);
3380
3381         usb_put_function_instance(&opts->func_inst);
3382 }
3383
3384 static struct configfs_item_operations ffs_item_ops = {
3385         .release        = ffs_attr_release,
3386 };
3387
3388 static struct config_item_type ffs_func_type = {
3389         .ct_item_ops    = &ffs_item_ops,
3390         .ct_owner       = THIS_MODULE,
3391 };
3392
3393
3394 /* Function registration interface ******************************************/
3395
3396 static void ffs_free_inst(struct usb_function_instance *f)
3397 {
3398         struct f_fs_opts *opts;
3399
3400         opts = to_f_fs_opts(f);
3401         ffs_dev_lock();
3402         _ffs_free_dev(opts->dev);
3403         ffs_dev_unlock();
3404         kfree(opts);
3405 }
3406
3407 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3408 {
3409         if (strlen(name) >= FIELD_SIZEOF(struct ffs_dev, name))
3410                 return -ENAMETOOLONG;
3411         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3412 }
3413
3414 static struct usb_function_instance *ffs_alloc_inst(void)
3415 {
3416         struct f_fs_opts *opts;
3417         struct ffs_dev *dev;
3418
3419         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3420         if (!opts)
3421                 return ERR_PTR(-ENOMEM);
3422
3423         opts->func_inst.set_inst_name = ffs_set_inst_name;
3424         opts->func_inst.free_func_inst = ffs_free_inst;
3425         ffs_dev_lock();
3426         dev = _ffs_alloc_dev();
3427         ffs_dev_unlock();
3428         if (IS_ERR(dev)) {
3429                 kfree(opts);
3430                 return ERR_CAST(dev);
3431         }
3432         opts->dev = dev;
3433         dev->opts = opts;
3434
3435         config_group_init_type_name(&opts->func_inst.group, "",
3436                                     &ffs_func_type);
3437         return &opts->func_inst;
3438 }
3439
3440 static void ffs_free(struct usb_function *f)
3441 {
3442         kfree(ffs_func_from_usb(f));
3443 }
3444
3445 static void ffs_func_unbind(struct usb_configuration *c,
3446                             struct usb_function *f)
3447 {
3448         struct ffs_function *func = ffs_func_from_usb(f);
3449         struct ffs_data *ffs = func->ffs;
3450         struct f_fs_opts *opts =
3451                 container_of(f->fi, struct f_fs_opts, func_inst);
3452         struct ffs_ep *ep = func->eps;
3453         unsigned count = ffs->eps_count;
3454         unsigned long flags;
3455
3456         ENTER();
3457         if (ffs->func == func) {
3458                 ffs_func_eps_disable(func);
3459                 ffs->func = NULL;
3460         }
3461
3462         if (!--opts->refcnt)
3463                 functionfs_unbind(ffs);
3464
3465         /* cleanup after autoconfig */
3466         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3467         while (count--) {
3468                 if (ep->ep && ep->req)
3469                         usb_ep_free_request(ep->ep, ep->req);
3470                 ep->req = NULL;
3471                 ++ep;
3472         }
3473         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3474         kfree(func->eps);
3475         func->eps = NULL;
3476         /*
3477          * eps, descriptors and interfaces_nums are allocated in the
3478          * same chunk so only one free is required.
3479          */
3480         func->function.fs_descriptors = NULL;
3481         func->function.hs_descriptors = NULL;
3482         func->function.ss_descriptors = NULL;
3483         func->interfaces_nums = NULL;
3484
3485         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3486 }
3487
3488 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3489 {
3490         struct ffs_function *func;
3491
3492         ENTER();
3493
3494         func = kzalloc(sizeof(*func), GFP_KERNEL);
3495         if (unlikely(!func))
3496                 return ERR_PTR(-ENOMEM);
3497
3498         func->function.name    = "Function FS Gadget";
3499
3500         func->function.bind    = ffs_func_bind;
3501         func->function.unbind  = ffs_func_unbind;
3502         func->function.set_alt = ffs_func_set_alt;
3503         func->function.disable = ffs_func_disable;
3504         func->function.setup   = ffs_func_setup;
3505         func->function.req_match = ffs_func_req_match;
3506         func->function.suspend = ffs_func_suspend;
3507         func->function.resume  = ffs_func_resume;
3508         func->function.free_func = ffs_free;
3509
3510         return &func->function;
3511 }
3512
3513 /*
3514  * ffs_lock must be taken by the caller of this function
3515  */
3516 static struct ffs_dev *_ffs_alloc_dev(void)
3517 {
3518         struct ffs_dev *dev;
3519         int ret;
3520
3521         if (_ffs_get_single_dev())
3522                         return ERR_PTR(-EBUSY);
3523
3524         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3525         if (!dev)
3526                 return ERR_PTR(-ENOMEM);
3527
3528         if (list_empty(&ffs_devices)) {
3529                 ret = functionfs_init();
3530                 if (ret) {
3531                         kfree(dev);
3532                         return ERR_PTR(ret);
3533                 }
3534         }
3535
3536         list_add(&dev->entry, &ffs_devices);
3537
3538         return dev;
3539 }
3540
3541 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3542 {
3543         struct ffs_dev *existing;
3544         int ret = 0;
3545
3546         ffs_dev_lock();
3547
3548         existing = _ffs_do_find_dev(name);
3549         if (!existing)
3550                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3551         else if (existing != dev)
3552                 ret = -EBUSY;
3553
3554         ffs_dev_unlock();
3555
3556         return ret;
3557 }
3558 EXPORT_SYMBOL_GPL(ffs_name_dev);
3559
3560 int ffs_single_dev(struct ffs_dev *dev)
3561 {
3562         int ret;
3563
3564         ret = 0;
3565         ffs_dev_lock();
3566
3567         if (!list_is_singular(&ffs_devices))
3568                 ret = -EBUSY;
3569         else
3570                 dev->single = true;
3571
3572         ffs_dev_unlock();
3573         return ret;
3574 }
3575 EXPORT_SYMBOL_GPL(ffs_single_dev);
3576
3577 /*
3578  * ffs_lock must be taken by the caller of this function
3579  */
3580 static void _ffs_free_dev(struct ffs_dev *dev)
3581 {
3582         list_del(&dev->entry);
3583
3584         /* Clear the private_data pointer to stop incorrect dev access */
3585         if (dev->ffs_data)
3586                 dev->ffs_data->private_data = NULL;
3587
3588         kfree(dev);
3589         if (list_empty(&ffs_devices))
3590                 functionfs_cleanup();
3591 }
3592
3593 static void *ffs_acquire_dev(const char *dev_name)
3594 {
3595         struct ffs_dev *ffs_dev;
3596
3597         ENTER();
3598         ffs_dev_lock();
3599
3600         ffs_dev = _ffs_find_dev(dev_name);
3601         if (!ffs_dev)
3602                 ffs_dev = ERR_PTR(-ENOENT);
3603         else if (ffs_dev->mounted)
3604                 ffs_dev = ERR_PTR(-EBUSY);
3605         else if (ffs_dev->ffs_acquire_dev_callback &&
3606             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3607                 ffs_dev = ERR_PTR(-ENOENT);
3608         else
3609                 ffs_dev->mounted = true;
3610
3611         ffs_dev_unlock();
3612         return ffs_dev;
3613 }
3614
3615 static void ffs_release_dev(struct ffs_data *ffs_data)
3616 {
3617         struct ffs_dev *ffs_dev;
3618
3619         ENTER();
3620         ffs_dev_lock();
3621
3622         ffs_dev = ffs_data->private_data;
3623         if (ffs_dev) {
3624                 ffs_dev->mounted = false;
3625
3626                 if (ffs_dev->ffs_release_dev_callback)
3627                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3628         }
3629
3630         ffs_dev_unlock();
3631 }
3632
3633 static int ffs_ready(struct ffs_data *ffs)
3634 {
3635         struct ffs_dev *ffs_obj;
3636         int ret = 0;
3637
3638         ENTER();
3639         ffs_dev_lock();
3640
3641         ffs_obj = ffs->private_data;
3642         if (!ffs_obj) {
3643                 ret = -EINVAL;
3644                 goto done;
3645         }
3646         if (WARN_ON(ffs_obj->desc_ready)) {
3647                 ret = -EBUSY;
3648                 goto done;
3649         }
3650
3651         ffs_obj->desc_ready = true;
3652         ffs_obj->ffs_data = ffs;
3653
3654         if (ffs_obj->ffs_ready_callback) {
3655                 ret = ffs_obj->ffs_ready_callback(ffs);
3656                 if (ret)
3657                         goto done;
3658         }
3659
3660         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3661 done:
3662         ffs_dev_unlock();
3663         return ret;
3664 }
3665
3666 static void ffs_closed(struct ffs_data *ffs)
3667 {
3668         struct ffs_dev *ffs_obj;
3669         struct f_fs_opts *opts;
3670         struct config_item *ci;
3671
3672         ENTER();
3673         ffs_dev_lock();
3674
3675         ffs_obj = ffs->private_data;
3676         if (!ffs_obj)
3677                 goto done;
3678
3679         ffs_obj->desc_ready = false;
3680
3681         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3682             ffs_obj->ffs_closed_callback)
3683                 ffs_obj->ffs_closed_callback(ffs);
3684
3685         if (ffs_obj->opts)
3686                 opts = ffs_obj->opts;
3687         else
3688                 goto done;
3689
3690         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3691             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3692                 goto done;
3693
3694         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3695         ffs_dev_unlock();
3696
3697         unregister_gadget_item(ci);
3698         return;
3699 done:
3700         ffs_dev_unlock();
3701 }
3702
3703 /* Misc helper functions ****************************************************/
3704
3705 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3706 {
3707         return nonblock
3708                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3709                 : mutex_lock_interruptible(mutex);
3710 }
3711
3712 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3713 {
3714         char *data;
3715
3716         if (unlikely(!len))
3717                 return NULL;
3718
3719         data = kmalloc(len, GFP_KERNEL);
3720         if (unlikely(!data))
3721                 return ERR_PTR(-ENOMEM);
3722
3723         if (unlikely(copy_from_user(data, buf, len))) {
3724                 kfree(data);
3725                 return ERR_PTR(-EFAULT);
3726         }
3727
3728         pr_vdebug("Buffer from user space:\n");
3729         ffs_dump_mem("", data, len);
3730
3731         return data;
3732 }
3733
3734 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3735 MODULE_LICENSE("GPL");
3736 MODULE_AUTHOR("Michal Nazarewicz");