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