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 int _ffs_name_dev(struct ffs_dev *dev, const char *name);
 250 static void _ffs_free_dev(struct ffs_dev *dev);
 251 static void *ffs_acquire_dev(const char *dev_name);
 252 static void ffs_release_dev(struct ffs_data *ffs_data);
 253 static int ffs_ready(struct ffs_data *ffs);
 254 static void ffs_closed(struct ffs_data *ffs);
 255
 256 /* Misc helper functions ****************************************************/
 257
 258 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 259         __attribute__((warn_unused_result, nonnull));
 260 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 261         __attribute__((warn_unused_result, nonnull));
 262
 263
 264 /* Control file aka ep0 *****************************************************/
 265
 266 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 267 {
 268         struct ffs_data *ffs = req->context;
 269
 270         complete(&ffs->ep0req_completion);
 271 }
 272
 273 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 274 {
 275         struct usb_request *req = ffs->ep0req;
 276         int ret;
 277
 278         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 279
 280         spin_unlock_irq(&ffs->ev.waitq.lock);
 281
 282         req->buf      = data;
 283         req->length   = len;
 284
 285         /*
 286          * UDC layer requires to provide a buffer even for ZLP, but should
 287          * not use it at all. Let's provide some poisoned pointer to catch
 288          * possible bug in the driver.
 289          */
 290         if (req->buf == NULL)
 291                 req->buf = (void *)0xDEADBABE;
 292
 293         reinit_completion(&ffs->ep0req_completion);
 294
 295         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 296         if (unlikely(ret < 0))
 297                 return ret;
 298
 299         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 300         if (unlikely(ret)) {
 301                 usb_ep_dequeue(ffs->gadget->ep0, req);
 302                 return -EINTR;
 303         }
 304
 305         ffs->setup_state = FFS_NO_SETUP;
 306         return req->status ? req->status : req->actual;
 307 }
 308
 309 static int __ffs_ep0_stall(struct ffs_data *ffs)
 310 {
 311         if (ffs->ev.can_stall) {
 312                 pr_vdebug("ep0 stall\n");
 313                 usb_ep_set_halt(ffs->gadget->ep0);
 314                 ffs->setup_state = FFS_NO_SETUP;
 315                 return -EL2HLT;
 316         } else {
 317                 pr_debug("bogus ep0 stall!\n");
 318                 return -ESRCH;
 319         }
 320 }
 321
 322 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 323                              size_t len, loff_t *ptr)
 324 {
 325         struct ffs_data *ffs = file->private_data;
 326         ssize_t ret;
 327         char *data;
 328
 329         ENTER();
 330
 331         /* Fast check if setup was canceled */
 332         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 333                 return -EIDRM;
 334
 335         /* Acquire mutex */
 336         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 337         if (unlikely(ret < 0))
 338                 return ret;
 339
 340         /* Check state */
 341         switch (ffs->state) {
 342         case FFS_READ_DESCRIPTORS:
 343         case FFS_READ_STRINGS:
 344                 /* Copy data */
 345                 if (unlikely(len < 16)) {
 346                         ret = -EINVAL;
 347                         break;
 348                 }
 349
 350                 data = ffs_prepare_buffer(buf, len);
 351                 if (IS_ERR(data)) {
 352                         ret = PTR_ERR(data);
 353                         break;
 354                 }
 355
 356                 /* Handle data */
 357                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 358                         pr_info("read descriptors\n");
 359                         ret = __ffs_data_got_descs(ffs, data, len);
 360                         if (unlikely(ret < 0))
 361                                 break;
 362
 363                         ffs->state = FFS_READ_STRINGS;
 364                         ret = len;
 365                 } else {
 366                         pr_info("read strings\n");
 367                         ret = __ffs_data_got_strings(ffs, data, len);
 368                         if (unlikely(ret < 0))
 369                                 break;
 370
 371                         ret = ffs_epfiles_create(ffs);
 372                         if (unlikely(ret)) {
 373                                 ffs->state = FFS_CLOSING;
 374                                 break;
 375                         }
 376
 377                         ffs->state = FFS_ACTIVE;
 378                         mutex_unlock(&ffs->mutex);
 379
 380                         ret = ffs_ready(ffs);
 381                         if (unlikely(ret < 0)) {
 382                                 ffs->state = FFS_CLOSING;
 383                                 return ret;
 384                         }
 385
 386                         return len;
 387                 }
 388                 break;
 389
 390         case FFS_ACTIVE:
 391                 data = NULL;
 392                 /*
 393                  * We're called from user space, we can use _irq
 394                  * rather then _irqsave
 395                  */
 396                 spin_lock_irq(&ffs->ev.waitq.lock);
 397                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 398                 case FFS_SETUP_CANCELLED:
 399                         ret = -EIDRM;
 400                         goto done_spin;
 401
 402                 case FFS_NO_SETUP:
 403                         ret = -ESRCH;
 404                         goto done_spin;
 405
 406                 case FFS_SETUP_PENDING:
 407                         break;
 408                 }
 409
 410                 /* FFS_SETUP_PENDING */
 411                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 412                         spin_unlock_irq(&ffs->ev.waitq.lock);
 413                         ret = __ffs_ep0_stall(ffs);
 414                         break;
 415                 }
 416
 417                 /* FFS_SETUP_PENDING and not stall */
 418                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 419
 420                 spin_unlock_irq(&ffs->ev.waitq.lock);
 421
 422                 data = ffs_prepare_buffer(buf, len);
 423                 if (IS_ERR(data)) {
 424                         ret = PTR_ERR(data);
 425                         break;
 426                 }
 427
 428                 spin_lock_irq(&ffs->ev.waitq.lock);
 429
 430                 /*
 431                  * We are guaranteed to be still in FFS_ACTIVE state
 432                  * but the state of setup could have changed from
 433                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 434                  * to check for that.  If that happened we copied data
 435                  * from user space in vain but it's unlikely.
 436                  *
 437                  * For sure we are not in FFS_NO_SETUP since this is
 438                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 439                  * transition can be performed and it's protected by
 440                  * mutex.
 441                  */
 442                 if (ffs_setup_state_clear_cancelled(ffs) ==
 443                     FFS_SETUP_CANCELLED) {
 444                         ret = -EIDRM;
 445 done_spin:
 446                         spin_unlock_irq(&ffs->ev.waitq.lock);
 447                 } else {
 448                         /* unlocks spinlock */
 449                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 450                 }
 451                 kfree(data);
 452                 break;
 453
 454         default:
 455                 ret = -EBADFD;
 456                 break;
 457         }
 458
 459         mutex_unlock(&ffs->mutex);
 460         return ret;
 461 }
 462
 463 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 464 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 465                                      size_t n)
 466 {
 467         /*
 468          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 469          * size of ffs->ev.types array (which is four) so that's how much space
 470          * we reserve.
 471          */
 472         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 473         const size_t size = n * sizeof *events;
 474         unsigned i = 0;
 475
 476         memset(events, 0, size);
 477
 478         do {
 479                 events[i].type = ffs->ev.types[i];
 480                 if (events[i].type == FUNCTIONFS_SETUP) {
 481                         events[i].u.setup = ffs->ev.setup;
 482                         ffs->setup_state = FFS_SETUP_PENDING;
 483                 }
 484         } while (++i < n);
 485
 486         ffs->ev.count -= n;
 487         if (ffs->ev.count)
 488                 memmove(ffs->ev.types, ffs->ev.types + n,
 489                         ffs->ev.count * sizeof *ffs->ev.types);
 490
 491         spin_unlock_irq(&ffs->ev.waitq.lock);
 492         mutex_unlock(&ffs->mutex);
 493
 494         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 495 }
 496
 497 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 498                             size_t len, loff_t *ptr)
 499 {
 500         struct ffs_data *ffs = file->private_data;
 501         char *data = NULL;
 502         size_t n;
 503         int ret;
 504
 505         ENTER();
 506
 507         /* Fast check if setup was canceled */
 508         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 509                 return -EIDRM;
 510
 511         /* Acquire mutex */
 512         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 513         if (unlikely(ret < 0))
 514                 return ret;
 515
 516         /* Check state */
 517         if (ffs->state != FFS_ACTIVE) {
 518                 ret = -EBADFD;
 519                 goto done_mutex;
 520         }
 521
 522         /*
 523          * We're called from user space, we can use _irq rather then
 524          * _irqsave
 525          */
 526         spin_lock_irq(&ffs->ev.waitq.lock);
 527
 528         switch (ffs_setup_state_clear_cancelled(ffs)) {
 529         case FFS_SETUP_CANCELLED:
 530                 ret = -EIDRM;
 531                 break;
 532
 533         case FFS_NO_SETUP:
 534                 n = len / sizeof(struct usb_functionfs_event);
 535                 if (unlikely(!n)) {
 536                         ret = -EINVAL;
 537                         break;
 538                 }
 539
 540                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 541                         ret = -EAGAIN;
 542                         break;
 543                 }
 544
 545                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 546                                                         ffs->ev.count)) {
 547                         ret = -EINTR;
 548                         break;
 549                 }
 550
 551                 return __ffs_ep0_read_events(ffs, buf,
 552                                              min(n, (size_t)ffs->ev.count));
 553
 554         case FFS_SETUP_PENDING:
 555                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 556                         spin_unlock_irq(&ffs->ev.waitq.lock);
 557                         ret = __ffs_ep0_stall(ffs);
 558                         goto done_mutex;
 559                 }
 560
 561                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 562
 563                 spin_unlock_irq(&ffs->ev.waitq.lock);
 564
 565                 if (likely(len)) {
 566                         data = kmalloc(len, GFP_KERNEL);
 567                         if (unlikely(!data)) {
 568                                 ret = -ENOMEM;
 569                                 goto done_mutex;
 570                         }
 571                 }
 572
 573                 spin_lock_irq(&ffs->ev.waitq.lock);
 574
 575                 /* See ffs_ep0_write() */
 576                 if (ffs_setup_state_clear_cancelled(ffs) ==
 577                     FFS_SETUP_CANCELLED) {
 578                         ret = -EIDRM;
 579                         break;
 580                 }
 581
 582                 /* unlocks spinlock */
 583                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 584                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 585                         ret = -EFAULT;
 586                 goto done_mutex;
 587
 588         default:
 589                 ret = -EBADFD;
 590                 break;
 591         }
 592
 593         spin_unlock_irq(&ffs->ev.waitq.lock);
 594 done_mutex:
 595         mutex_unlock(&ffs->mutex);
 596         kfree(data);
 597         return ret;
 598 }
 599
 600 static int ffs_ep0_open(struct inode *inode, struct file *file)
 601 {
 602         struct ffs_data *ffs = inode->i_private;
 603
 604         ENTER();
 605
 606         if (unlikely(ffs->state == FFS_CLOSING))
 607                 return -EBUSY;
 608
 609         file->private_data = ffs;
 610         ffs_data_opened(ffs);
 611
 612         return 0;
 613 }
 614
 615 static int ffs_ep0_release(struct inode *inode, struct file *file)
 616 {
 617         struct ffs_data *ffs = file->private_data;
 618
 619         ENTER();
 620
 621         ffs_data_closed(ffs);
 622
 623         return 0;
 624 }
 625
 626 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 627 {
 628         struct ffs_data *ffs = file->private_data;
 629         struct usb_gadget *gadget = ffs->gadget;
 630         long ret;
 631
 632         ENTER();
 633
 634         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 635                 struct ffs_function *func = ffs->func;
 636                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 637         } else if (gadget && gadget->ops->ioctl) {
 638                 ret = gadget->ops->ioctl(gadget, code, value);
 639         } else {
 640                 ret = -ENOTTY;
 641         }
 642
 643         return ret;
 644 }
 645
 646 static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
 647 {
 648         struct ffs_data *ffs = file->private_data;
 649         unsigned int mask = POLLWRNORM;
 650         int ret;
 651
 652         poll_wait(file, &ffs->ev.waitq, wait);
 653
 654         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 655         if (unlikely(ret < 0))
 656                 return mask;
 657
 658         switch (ffs->state) {
 659         case FFS_READ_DESCRIPTORS:
 660         case FFS_READ_STRINGS:
 661                 mask |= POLLOUT;
 662                 break;
 663
 664         case FFS_ACTIVE:
 665                 switch (ffs->setup_state) {
 666                 case FFS_NO_SETUP:
 667                         if (ffs->ev.count)
 668                                 mask |= POLLIN;
 669                         break;
 670
 671                 case FFS_SETUP_PENDING:
 672                 case FFS_SETUP_CANCELLED:
 673                         mask |= (POLLIN | POLLOUT);
 674                         break;
 675                 }
 676         case FFS_CLOSING:
 677                 break;
 678         case FFS_DEACTIVATED:
 679                 break;
 680         }
 681
 682         mutex_unlock(&ffs->mutex);
 683
 684         return mask;
 685 }
 686
 687 static const struct file_operations ffs_ep0_operations = {
 688         .llseek =       no_llseek,
 689
 690         .open =         ffs_ep0_open,
 691         .write =        ffs_ep0_write,
 692         .read =         ffs_ep0_read,
 693         .release =      ffs_ep0_release,
 694         .unlocked_ioctl =       ffs_ep0_ioctl,
 695         .poll =         ffs_ep0_poll,
 696 };
 697
 698
 699 /* "Normal" endpoints operations ********************************************/
 700
 701 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 702 {
 703         ENTER();
 704         if (likely(req->context)) {
 705                 struct ffs_ep *ep = _ep->driver_data;
 706                 ep->status = req->status ? req->status : req->actual;
 707                 complete(req->context);
 708         }
 709 }
 710
 711 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 712 {
 713         ssize_t ret = copy_to_iter(data, data_len, iter);
 714         if (likely(ret == data_len))
 715                 return ret;
 716
 717         if (unlikely(iov_iter_count(iter)))
 718                 return -EFAULT;
 719
 720         /*
 721          * Dear user space developer!
 722          *
 723          * TL;DR: To stop getting below error message in your kernel log, change
 724          * user space code using functionfs to align read buffers to a max
 725          * packet size.
 726          *
 727          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 728          * packet size.  When unaligned buffer is passed to functionfs, it
 729          * internally uses a larger, aligned buffer so that such UDCs are happy.
 730          *
 731          * Unfortunately, this means that host may send more data than was
 732          * requested in read(2) system call.  f_fs doesn’t know what to do with
 733          * that excess data so it simply drops it.
 734          *
 735          * Was the buffer aligned in the first place, no such problem would
 736          * happen.
 737          *
 738          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 739          * by splitting a request into multiple parts.  This splitting may still
 740          * be a problem though so it’s likely best to align the buffer
 741          * regardless of it being AIO or not..
 742          *
 743          * This only affects OUT endpoints, i.e. reading data with a read(2),
 744          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 745          * affected.
 746          */
 747         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 748                "Align read buffer size to max packet size to avoid the problem.\n",
 749                data_len, ret);
 750
 751         return ret;
 752 }
 753
 754 static void ffs_user_copy_worker(struct work_struct *work)
 755 {
 756         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 757                                                    work);
 758         int ret = io_data->req->status ? io_data->req->status :
 759                                          io_data->req->actual;
 760         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 761
 762         if (io_data->read && ret > 0) {
 763                 use_mm(io_data->mm);
 764                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 765                 unuse_mm(io_data->mm);
 766         }
 767
 768         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 769
 770         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 771                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 772
 773         usb_ep_free_request(io_data->ep, io_data->req);
 774
 775         if (io_data->read)
 776                 kfree(io_data->to_free);
 777         kfree(io_data->buf);
 778         kfree(io_data);
 779 }
 780
 781 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 782                                          struct usb_request *req)
 783 {
 784         struct ffs_io_data *io_data = req->context;
 785
 786         ENTER();
 787
 788         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 789         schedule_work(&io_data->work);
 790 }
 791
 792 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 793 {
 794         /*
 795          * See comment in struct ffs_epfile for full read_buffer pointer
 796          * synchronisation story.
 797          */
 798         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 799         if (buf && buf != READ_BUFFER_DROP)
 800                 kfree(buf);
 801 }
 802
 803 /* Assumes epfile->mutex is held. */
 804 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 805                                           struct iov_iter *iter)
 806 {
 807         /*
 808          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 809          * the buffer while we are using it.  See comment in struct ffs_epfile
 810          * for full read_buffer pointer synchronisation story.
 811          */
 812         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 813         ssize_t ret;
 814         if (!buf || buf == READ_BUFFER_DROP)
 815                 return 0;
 816
 817         ret = copy_to_iter(buf->data, buf->length, iter);
 818         if (buf->length == ret) {
 819                 kfree(buf);
 820                 return ret;
 821         }
 822
 823         if (unlikely(iov_iter_count(iter))) {
 824                 ret = -EFAULT;
 825         } else {
 826                 buf->length -= ret;
 827                 buf->data += ret;
 828         }
 829
 830         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 831                 kfree(buf);
 832
 833         return ret;
 834 }
 835
 836 /* Assumes epfile->mutex is held. */
 837 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 838                                       void *data, int data_len,
 839                                       struct iov_iter *iter)
 840 {
 841         struct ffs_buffer *buf;
 842
 843         ssize_t ret = copy_to_iter(data, data_len, iter);
 844         if (likely(data_len == ret))
 845                 return ret;
 846
 847         if (unlikely(iov_iter_count(iter)))
 848                 return -EFAULT;
 849
 850         /* See ffs_copy_to_iter for more context. */
 851         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 852                 data_len, ret);
 853
 854         data_len -= ret;
 855         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 856         if (!buf)
 857                 return -ENOMEM;
 858         buf->length = data_len;
 859         buf->data = buf->storage;
 860         memcpy(buf->storage, data + ret, data_len);
 861
 862         /*
 863          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 864          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 865          * in struct ffs_epfile for full read_buffer pointer synchronisation
 866          * story.
 867          */
 868         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 869                 kfree(buf);
 870
 871         return ret;
 872 }
 873
 874 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 875 {
 876         struct ffs_epfile *epfile = file->private_data;
 877         struct usb_request *req;
 878         struct ffs_ep *ep;
 879         char *data = NULL;
 880         ssize_t ret, data_len = -EINVAL;
 881         int halt;
 882
 883         /* Are we still active? */
 884         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 885                 return -ENODEV;
 886
 887         /* Wait for endpoint to be enabled */
 888         ep = epfile->ep;
 889         if (!ep) {
 890                 if (file->f_flags & O_NONBLOCK)
 891                         return -EAGAIN;
 892
 893                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
 894                 if (ret)
 895                         return -EINTR;
 896         }
 897
 898         /* Do we halt? */
 899         halt = (!io_data->read == !epfile->in);
 900         if (halt && epfile->isoc)
 901                 return -EINVAL;
 902
 903         /* We will be using request and read_buffer */
 904         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 905         if (unlikely(ret))
 906                 goto error;
 907
 908         /* Allocate & copy */
 909         if (!halt) {
 910                 struct usb_gadget *gadget;
 911
 912                 /*
 913                  * Do we have buffered data from previous partial read?  Check
 914                  * that for synchronous case only because we do not have
 915                  * facility to ‘wake up’ a pending asynchronous read and push
 916                  * buffered data to it which we would need to make things behave
 917                  * consistently.
 918                  */
 919                 if (!io_data->aio && io_data->read) {
 920                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 921                         if (ret)
 922                                 goto error_mutex;
 923                 }
 924
 925                 /*
 926                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 927                  * before the waiting completes, so do not assign to 'gadget'
 928                  * earlier
 929                  */
 930                 gadget = epfile->ffs->gadget;
 931
 932                 spin_lock_irq(&epfile->ffs->eps_lock);
 933                 /* In the meantime, endpoint got disabled or changed. */
 934                 if (epfile->ep != ep) {
 935                         ret = -ESHUTDOWN;
 936                         goto error_lock;
 937                 }
 938                 data_len = iov_iter_count(&io_data->data);
 939                 /*
 940                  * Controller may require buffer size to be aligned to
 941                  * maxpacketsize of an out endpoint.
 942                  */
 943                 if (io_data->read)
 944                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
 945                 spin_unlock_irq(&epfile->ffs->eps_lock);
 946
 947                 data = kmalloc(data_len, GFP_KERNEL);
 948                 if (unlikely(!data)) {
 949                         ret = -ENOMEM;
 950                         goto error_mutex;
 951                 }
 952                 if (!io_data->read &&
 953                     !copy_from_iter_full(data, data_len, &io_data->data)) {
 954                         ret = -EFAULT;
 955                         goto error_mutex;
 956                 }
 957         }
 958
 959         spin_lock_irq(&epfile->ffs->eps_lock);
 960
 961         if (epfile->ep != ep) {
 962                 /* In the meantime, endpoint got disabled or changed. */
 963                 ret = -ESHUTDOWN;
 964         } else if (halt) {
 965                 /* Halt */
 966                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 967                         usb_ep_set_halt(ep->ep);
 968                 ret = -EBADMSG;
 969         } else if (unlikely(data_len == -EINVAL)) {
 970                 /*
 971                  * Sanity Check: even though data_len can't be used
 972                  * uninitialized at the time I write this comment, some
 973                  * compilers complain about this situation.
 974                  * In order to keep the code clean from warnings, data_len is
 975                  * being initialized to -EINVAL during its declaration, which
 976                  * means we can't rely on compiler anymore to warn no future
 977                  * changes won't result in data_len being used uninitialized.
 978                  * For such reason, we're adding this redundant sanity check
 979                  * here.
 980                  */
 981                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
 982                 ret = -EINVAL;
 983         } else if (!io_data->aio) {
 984                 DECLARE_COMPLETION_ONSTACK(done);
 985                 bool interrupted = false;
 986
 987                 req = ep->req;
 988                 req->buf      = data;
 989                 req->length   = data_len;
 990
 991                 req->context  = &done;
 992                 req->complete = ffs_epfile_io_complete;
 993
 994                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 995                 if (unlikely(ret < 0))
 996                         goto error_lock;
 997
 998                 spin_unlock_irq(&epfile->ffs->eps_lock);
 999
1000                 if (unlikely(wait_for_completion_interruptible(&done))) {
1001                         /*
1002                          * To avoid race condition with ffs_epfile_io_complete,
1003                          * dequeue the request first then check
1004                          * status. usb_ep_dequeue API should guarantee no race
1005                          * condition with req->complete callback.
1006                          */
1007                         usb_ep_dequeue(ep->ep, req);
1008                         interrupted = ep->status < 0;
1009                 }
1010
1011                 if (interrupted)
1012                         ret = -EINTR;
1013                 else if (io_data->read && ep->status > 0)
1014                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1015                                                      &io_data->data);
1016                 else
1017                         ret = ep->status;
1018                 goto error_mutex;
1019         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_KERNEL))) {
1020                 ret = -ENOMEM;
1021         } else {
1022                 req->buf      = data;
1023                 req->length   = data_len;
1024
1025                 io_data->buf = data;
1026                 io_data->ep = ep->ep;
1027                 io_data->req = req;
1028                 io_data->ffs = epfile->ffs;
1029
1030                 req->context  = io_data;
1031                 req->complete = ffs_epfile_async_io_complete;
1032
1033                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1034                 if (unlikely(ret)) {
1035                         usb_ep_free_request(ep->ep, req);
1036                         goto error_lock;
1037                 }
1038
1039                 ret = -EIOCBQUEUED;
1040                 /*
1041                  * Do not kfree the buffer in this function.  It will be freed
1042                  * by ffs_user_copy_worker.
1043                  */
1044                 data = NULL;
1045         }
1046
1047 error_lock:
1048         spin_unlock_irq(&epfile->ffs->eps_lock);
1049 error_mutex:
1050         mutex_unlock(&epfile->mutex);
1051 error:
1052         kfree(data);
1053         return ret;
1054 }
1055
1056 static int
1057 ffs_epfile_open(struct inode *inode, struct file *file)
1058 {
1059         struct ffs_epfile *epfile = inode->i_private;
1060
1061         ENTER();
1062
1063         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1064                 return -ENODEV;
1065
1066         file->private_data = epfile;
1067         ffs_data_opened(epfile->ffs);
1068
1069         return 0;
1070 }
1071
1072 static int ffs_aio_cancel(struct kiocb *kiocb)
1073 {
1074         struct ffs_io_data *io_data = kiocb->private;
1075         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1076         int value;
1077
1078         ENTER();
1079
1080         spin_lock_irq(&epfile->ffs->eps_lock);
1081
1082         if (likely(io_data && io_data->ep && io_data->req))
1083                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1084         else
1085                 value = -EINVAL;
1086
1087         spin_unlock_irq(&epfile->ffs->eps_lock);
1088
1089         return value;
1090 }
1091
1092 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1093 {
1094         struct ffs_io_data io_data, *p = &io_data;
1095         ssize_t res;
1096
1097         ENTER();
1098
1099         if (!is_sync_kiocb(kiocb)) {
1100                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1101                 if (unlikely(!p))
1102                         return -ENOMEM;
1103                 p->aio = true;
1104         } else {
1105                 p->aio = false;
1106         }
1107
1108         p->read = false;
1109         p->kiocb = kiocb;
1110         p->data = *from;
1111         p->mm = current->mm;
1112
1113         kiocb->private = p;
1114
1115         if (p->aio)
1116                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1117
1118         res = ffs_epfile_io(kiocb->ki_filp, p);
1119         if (res == -EIOCBQUEUED)
1120                 return res;
1121         if (p->aio)
1122                 kfree(p);
1123         else
1124                 *from = p->data;
1125         return res;
1126 }
1127
1128 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1129 {
1130         struct ffs_io_data io_data, *p = &io_data;
1131         ssize_t res;
1132
1133         ENTER();
1134
1135         if (!is_sync_kiocb(kiocb)) {
1136                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1137                 if (unlikely(!p))
1138                         return -ENOMEM;
1139                 p->aio = true;
1140         } else {
1141                 p->aio = false;
1142         }
1143
1144         p->read = true;
1145         p->kiocb = kiocb;
1146         if (p->aio) {
1147                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1148                 if (!p->to_free) {
1149                         kfree(p);
1150                         return -ENOMEM;
1151                 }
1152         } else {
1153                 p->data = *to;
1154                 p->to_free = NULL;
1155         }
1156         p->mm = current->mm;
1157
1158         kiocb->private = p;
1159
1160         if (p->aio)
1161                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1162
1163         res = ffs_epfile_io(kiocb->ki_filp, p);
1164         if (res == -EIOCBQUEUED)
1165                 return res;
1166
1167         if (p->aio) {
1168                 kfree(p->to_free);
1169                 kfree(p);
1170         } else {
1171                 *to = p->data;
1172         }
1173         return res;
1174 }
1175
1176 static int
1177 ffs_epfile_release(struct inode *inode, struct file *file)
1178 {
1179         struct ffs_epfile *epfile = inode->i_private;
1180
1181         ENTER();
1182
1183         __ffs_epfile_read_buffer_free(epfile);
1184         ffs_data_closed(epfile->ffs);
1185
1186         return 0;
1187 }
1188
1189 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1190                              unsigned long value)
1191 {
1192         struct ffs_epfile *epfile = file->private_data;
1193         int ret;
1194
1195         ENTER();
1196
1197         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1198                 return -ENODEV;
1199
1200         spin_lock_irq(&epfile->ffs->eps_lock);
1201         if (likely(epfile->ep)) {
1202                 switch (code) {
1203                 case FUNCTIONFS_FIFO_STATUS:
1204                         ret = usb_ep_fifo_status(epfile->ep->ep);
1205                         break;
1206                 case FUNCTIONFS_FIFO_FLUSH:
1207                         usb_ep_fifo_flush(epfile->ep->ep);
1208                         ret = 0;
1209                         break;
1210                 case FUNCTIONFS_CLEAR_HALT:
1211                         ret = usb_ep_clear_halt(epfile->ep->ep);
1212                         break;
1213                 case FUNCTIONFS_ENDPOINT_REVMAP:
1214                         ret = epfile->ep->num;
1215                         break;
1216                 case FUNCTIONFS_ENDPOINT_DESC:
1217                 {
1218                         int desc_idx;
1219                         struct usb_endpoint_descriptor *desc;
1220
1221                         switch (epfile->ffs->gadget->speed) {
1222                         case USB_SPEED_SUPER:
1223                                 desc_idx = 2;
1224                                 break;
1225                         case USB_SPEED_HIGH:
1226                                 desc_idx = 1;
1227                                 break;
1228                         default:
1229                                 desc_idx = 0;
1230                         }
1231                         desc = epfile->ep->descs[desc_idx];
1232
1233                         spin_unlock_irq(&epfile->ffs->eps_lock);
1234                         ret = copy_to_user((void *)value, desc, desc->bLength);
1235                         if (ret)
1236                                 ret = -EFAULT;
1237                         return ret;
1238                 }
1239                 default:
1240                         ret = -ENOTTY;
1241                 }
1242         } else {
1243                 ret = -ENODEV;
1244         }
1245         spin_unlock_irq(&epfile->ffs->eps_lock);
1246
1247         return ret;
1248 }
1249
1250 static const struct file_operations ffs_epfile_operations = {
1251         .llseek =       no_llseek,
1252
1253         .open =         ffs_epfile_open,
1254         .write_iter =   ffs_epfile_write_iter,
1255         .read_iter =    ffs_epfile_read_iter,
1256         .release =      ffs_epfile_release,
1257         .unlocked_ioctl =       ffs_epfile_ioctl,
1258 };
1259
1260
1261 /* File system and super block operations ***********************************/
1262
1263 /*
1264  * Mounting the file system creates a controller file, used first for
1265  * function configuration then later for event monitoring.
1266  */
1267
1268 static struct inode *__must_check
1269 ffs_sb_make_inode(struct super_block *sb, void *data,
1270                   const struct file_operations *fops,
1271                   const struct inode_operations *iops,
1272                   struct ffs_file_perms *perms)
1273 {
1274         struct inode *inode;
1275
1276         ENTER();
1277
1278         inode = new_inode(sb);
1279
1280         if (likely(inode)) {
1281                 struct timespec ts = current_time(inode);
1282
1283                 inode->i_ino     = get_next_ino();
1284                 inode->i_mode    = perms->mode;
1285                 inode->i_uid     = perms->uid;
1286                 inode->i_gid     = perms->gid;
1287                 inode->i_atime   = ts;
1288                 inode->i_mtime   = ts;
1289                 inode->i_ctime   = ts;
1290                 inode->i_private = data;
1291                 if (fops)
1292                         inode->i_fop = fops;
1293                 if (iops)
1294                         inode->i_op  = iops;
1295         }
1296
1297         return inode;
1298 }
1299
1300 /* Create "regular" file */
1301 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1302                                         const char *name, void *data,
1303                                         const struct file_operations *fops)
1304 {
1305         struct ffs_data *ffs = sb->s_fs_info;
1306         struct dentry   *dentry;
1307         struct inode    *inode;
1308
1309         ENTER();
1310
1311         dentry = d_alloc_name(sb->s_root, name);
1312         if (unlikely(!dentry))
1313                 return NULL;
1314
1315         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1316         if (unlikely(!inode)) {
1317                 dput(dentry);
1318                 return NULL;
1319         }
1320
1321         d_add(dentry, inode);
1322         return dentry;
1323 }
1324
1325 /* Super block */
1326 static const struct super_operations ffs_sb_operations = {
1327         .statfs =       simple_statfs,
1328         .drop_inode =   generic_delete_inode,
1329 };
1330
1331 struct ffs_sb_fill_data {
1332         struct ffs_file_perms perms;
1333         umode_t root_mode;
1334         const char *dev_name;
1335         bool no_disconnect;
1336         struct ffs_data *ffs_data;
1337 };
1338
1339 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1340 {
1341         struct ffs_sb_fill_data *data = _data;
1342         struct inode    *inode;
1343         struct ffs_data *ffs = data->ffs_data;
1344
1345         ENTER();
1346
1347         ffs->sb              = sb;
1348         data->ffs_data       = NULL;
1349         sb->s_fs_info        = ffs;
1350         sb->s_blocksize      = PAGE_SIZE;
1351         sb->s_blocksize_bits = PAGE_SHIFT;
1352         sb->s_magic          = FUNCTIONFS_MAGIC;
1353         sb->s_op             = &ffs_sb_operations;
1354         sb->s_time_gran      = 1;
1355
1356         /* Root inode */
1357         data->perms.mode = data->root_mode;
1358         inode = ffs_sb_make_inode(sb, NULL,
1359                                   &simple_dir_operations,
1360                                   &simple_dir_inode_operations,
1361                                   &data->perms);
1362         sb->s_root = d_make_root(inode);
1363         if (unlikely(!sb->s_root))
1364                 return -ENOMEM;
1365
1366         /* EP0 file */
1367         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1368                                          &ffs_ep0_operations)))
1369                 return -ENOMEM;
1370
1371         return 0;
1372 }
1373
1374 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1375 {
1376         ENTER();
1377
1378         if (!opts || !*opts)
1379                 return 0;
1380
1381         for (;;) {
1382                 unsigned long value;
1383                 char *eq, *comma;
1384
1385                 /* Option limit */
1386                 comma = strchr(opts, ',');
1387                 if (comma)
1388                         *comma = 0;
1389
1390                 /* Value limit */
1391                 eq = strchr(opts, '=');
1392                 if (unlikely(!eq)) {
1393                         pr_err("'=' missing in %s\n", opts);
1394                         return -EINVAL;
1395                 }
1396                 *eq = 0;
1397
1398                 /* Parse value */
1399                 if (kstrtoul(eq + 1, 0, &value)) {
1400                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1401                         return -EINVAL;
1402                 }
1403
1404                 /* Interpret option */
1405                 switch (eq - opts) {
1406                 case 13:
1407                         if (!memcmp(opts, "no_disconnect", 13))
1408                                 data->no_disconnect = !!value;
1409                         else
1410                                 goto invalid;
1411                         break;
1412                 case 5:
1413                         if (!memcmp(opts, "rmode", 5))
1414                                 data->root_mode  = (value & 0555) | S_IFDIR;
1415                         else if (!memcmp(opts, "fmode", 5))
1416                                 data->perms.mode = (value & 0666) | S_IFREG;
1417                         else
1418                                 goto invalid;
1419                         break;
1420
1421                 case 4:
1422                         if (!memcmp(opts, "mode", 4)) {
1423                                 data->root_mode  = (value & 0555) | S_IFDIR;
1424                                 data->perms.mode = (value & 0666) | S_IFREG;
1425                         } else {
1426                                 goto invalid;
1427                         }
1428                         break;
1429
1430                 case 3:
1431                         if (!memcmp(opts, "uid", 3)) {
1432                                 data->perms.uid = make_kuid(current_user_ns(), value);
1433                                 if (!uid_valid(data->perms.uid)) {
1434                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1435                                         return -EINVAL;
1436                                 }
1437                         } else if (!memcmp(opts, "gid", 3)) {
1438                                 data->perms.gid = make_kgid(current_user_ns(), value);
1439                                 if (!gid_valid(data->perms.gid)) {
1440                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1441                                         return -EINVAL;
1442                                 }
1443                         } else {
1444                                 goto invalid;
1445                         }
1446                         break;
1447
1448                 default:
1449 invalid:
1450                         pr_err("%s: invalid option\n", opts);
1451                         return -EINVAL;
1452                 }
1453
1454                 /* Next iteration */
1455                 if (!comma)
1456                         break;
1457                 opts = comma + 1;
1458         }
1459
1460         return 0;
1461 }
1462
1463 /* "mount -t functionfs dev_name /dev/function" ends up here */
1464
1465 static struct dentry *
1466 ffs_fs_mount(struct file_system_type *t, int flags,
1467               const char *dev_name, void *opts)
1468 {
1469         struct ffs_sb_fill_data data = {
1470                 .perms = {
1471                         .mode = S_IFREG | 0600,
1472                         .uid = GLOBAL_ROOT_UID,
1473                         .gid = GLOBAL_ROOT_GID,
1474                 },
1475                 .root_mode = S_IFDIR | 0500,
1476                 .no_disconnect = false,
1477         };
1478         struct dentry *rv;
1479         int ret;
1480         void *ffs_dev;
1481         struct ffs_data *ffs;
1482
1483         ENTER();
1484
1485         ret = ffs_fs_parse_opts(&data, opts);
1486         if (unlikely(ret < 0))
1487                 return ERR_PTR(ret);
1488
1489         ffs = ffs_data_new();
1490         if (unlikely(!ffs))
1491                 return ERR_PTR(-ENOMEM);
1492         ffs->file_perms = data.perms;
1493         ffs->no_disconnect = data.no_disconnect;
1494
1495         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1496         if (unlikely(!ffs->dev_name)) {
1497                 ffs_data_put(ffs);
1498                 return ERR_PTR(-ENOMEM);
1499         }
1500
1501         ffs_dev = ffs_acquire_dev(dev_name);
1502         if (IS_ERR(ffs_dev)) {
1503                 ffs_data_put(ffs);
1504                 return ERR_CAST(ffs_dev);
1505         }
1506         ffs->private_data = ffs_dev;
1507         data.ffs_data = ffs;
1508
1509         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1510         if (IS_ERR(rv) && data.ffs_data) {
1511                 ffs_release_dev(data.ffs_data);
1512                 ffs_data_put(data.ffs_data);
1513         }
1514         return rv;
1515 }
1516
1517 static void
1518 ffs_fs_kill_sb(struct super_block *sb)
1519 {
1520         ENTER();
1521
1522         kill_litter_super(sb);
1523         if (sb->s_fs_info) {
1524                 ffs_release_dev(sb->s_fs_info);
1525                 ffs_data_closed(sb->s_fs_info);
1526                 ffs_data_put(sb->s_fs_info);
1527         }
1528 }
1529
1530 static struct file_system_type ffs_fs_type = {
1531         .owner          = THIS_MODULE,
1532         .name           = "functionfs",
1533         .mount          = ffs_fs_mount,
1534         .kill_sb        = ffs_fs_kill_sb,
1535 };
1536 MODULE_ALIAS_FS("functionfs");
1537
1538
1539 /* Driver's main init/cleanup functions *************************************/
1540
1541 static int functionfs_init(void)
1542 {
1543         int ret;
1544
1545         ENTER();
1546
1547         ret = register_filesystem(&ffs_fs_type);
1548         if (likely(!ret))
1549                 pr_info("file system registered\n");
1550         else
1551                 pr_err("failed registering file system (%d)\n", ret);
1552
1553         return ret;
1554 }
1555
1556 static void functionfs_cleanup(void)
1557 {
1558         ENTER();
1559
1560         pr_info("unloading\n");
1561         unregister_filesystem(&ffs_fs_type);
1562 }
1563
1564
1565 /* ffs_data and ffs_function construction and destruction code **************/
1566
1567 static void ffs_data_clear(struct ffs_data *ffs);
1568 static void ffs_data_reset(struct ffs_data *ffs);
1569
1570 static void ffs_data_get(struct ffs_data *ffs)
1571 {
1572         ENTER();
1573
1574         atomic_inc(&ffs->ref);
1575 }
1576
1577 static void ffs_data_opened(struct ffs_data *ffs)
1578 {
1579         ENTER();
1580
1581         atomic_inc(&ffs->ref);
1582         if (atomic_add_return(1, &ffs->opened) == 1 &&
1583                         ffs->state == FFS_DEACTIVATED) {
1584                 ffs->state = FFS_CLOSING;
1585                 ffs_data_reset(ffs);
1586         }
1587 }
1588
1589 static void ffs_data_put(struct ffs_data *ffs)
1590 {
1591         ENTER();
1592
1593         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1594                 pr_info("%s(): freeing\n", __func__);
1595                 ffs_data_clear(ffs);
1596                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1597                        waitqueue_active(&ffs->ep0req_completion.wait));
1598                 kfree(ffs->dev_name);
1599                 kfree(ffs);
1600         }
1601 }
1602
1603 static void ffs_data_closed(struct ffs_data *ffs)
1604 {
1605         ENTER();
1606
1607         if (atomic_dec_and_test(&ffs->opened)) {
1608                 if (ffs->no_disconnect) {
1609                         ffs->state = FFS_DEACTIVATED;
1610                         if (ffs->epfiles) {
1611                                 ffs_epfiles_destroy(ffs->epfiles,
1612                                                    ffs->eps_count);
1613                                 ffs->epfiles = NULL;
1614                         }
1615                         if (ffs->setup_state == FFS_SETUP_PENDING)
1616                                 __ffs_ep0_stall(ffs);
1617                 } else {
1618                         ffs->state = FFS_CLOSING;
1619                         ffs_data_reset(ffs);
1620                 }
1621         }
1622         if (atomic_read(&ffs->opened) < 0) {
1623                 ffs->state = FFS_CLOSING;
1624                 ffs_data_reset(ffs);
1625         }
1626
1627         ffs_data_put(ffs);
1628 }
1629
1630 static struct ffs_data *ffs_data_new(void)
1631 {
1632         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1633         if (unlikely(!ffs))
1634                 return NULL;
1635
1636         ENTER();
1637
1638         atomic_set(&ffs->ref, 1);
1639         atomic_set(&ffs->opened, 0);
1640         ffs->state = FFS_READ_DESCRIPTORS;
1641         mutex_init(&ffs->mutex);
1642         spin_lock_init(&ffs->eps_lock);
1643         init_waitqueue_head(&ffs->ev.waitq);
1644         init_completion(&ffs->ep0req_completion);
1645
1646         /* XXX REVISIT need to update it in some places, or do we? */
1647         ffs->ev.can_stall = 1;
1648
1649         return ffs;
1650 }
1651
1652 static void ffs_data_clear(struct ffs_data *ffs)
1653 {
1654         ENTER();
1655
1656         ffs_closed(ffs);
1657
1658         BUG_ON(ffs->gadget);
1659
1660         if (ffs->epfiles)
1661                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1662
1663         if (ffs->ffs_eventfd)
1664                 eventfd_ctx_put(ffs->ffs_eventfd);
1665
1666         kfree(ffs->raw_descs_data);
1667         kfree(ffs->raw_strings);
1668         kfree(ffs->stringtabs);
1669 }
1670
1671 static void ffs_data_reset(struct ffs_data *ffs)
1672 {
1673         ENTER();
1674
1675         ffs_data_clear(ffs);
1676
1677         ffs->epfiles = NULL;
1678         ffs->raw_descs_data = NULL;
1679         ffs->raw_descs = NULL;
1680         ffs->raw_strings = NULL;
1681         ffs->stringtabs = NULL;
1682
1683         ffs->raw_descs_length = 0;
1684         ffs->fs_descs_count = 0;
1685         ffs->hs_descs_count = 0;
1686         ffs->ss_descs_count = 0;
1687
1688         ffs->strings_count = 0;
1689         ffs->interfaces_count = 0;
1690         ffs->eps_count = 0;
1691
1692         ffs->ev.count = 0;
1693
1694         ffs->state = FFS_READ_DESCRIPTORS;
1695         ffs->setup_state = FFS_NO_SETUP;
1696         ffs->flags = 0;
1697 }
1698
1699
1700 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1701 {
1702         struct usb_gadget_strings **lang;
1703         int first_id;
1704
1705         ENTER();
1706
1707         if (WARN_ON(ffs->state != FFS_ACTIVE
1708                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1709                 return -EBADFD;
1710
1711         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1712         if (unlikely(first_id < 0))
1713                 return first_id;
1714
1715         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1716         if (unlikely(!ffs->ep0req))
1717                 return -ENOMEM;
1718         ffs->ep0req->complete = ffs_ep0_complete;
1719         ffs->ep0req->context = ffs;
1720
1721         lang = ffs->stringtabs;
1722         if (lang) {
1723                 for (; *lang; ++lang) {
1724                         struct usb_string *str = (*lang)->strings;
1725                         int id = first_id;
1726                         for (; str->s; ++id, ++str)
1727                                 str->id = id;
1728                 }
1729         }
1730
1731         ffs->gadget = cdev->gadget;
1732         ffs_data_get(ffs);
1733         return 0;
1734 }
1735
1736 static void functionfs_unbind(struct ffs_data *ffs)
1737 {
1738         ENTER();
1739
1740         if (!WARN_ON(!ffs->gadget)) {
1741                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1742                 ffs->ep0req = NULL;
1743                 ffs->gadget = NULL;
1744                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1745                 ffs_data_put(ffs);
1746         }
1747 }
1748
1749 static int ffs_epfiles_create(struct ffs_data *ffs)
1750 {
1751         struct ffs_epfile *epfile, *epfiles;
1752         unsigned i, count;
1753
1754         ENTER();
1755
1756         count = ffs->eps_count;
1757         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1758         if (!epfiles)
1759                 return -ENOMEM;
1760
1761         epfile = epfiles;
1762         for (i = 1; i <= count; ++i, ++epfile) {
1763                 epfile->ffs = ffs;
1764                 mutex_init(&epfile->mutex);
1765                 init_waitqueue_head(&epfile->wait);
1766                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1767                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1768                 else
1769                         sprintf(epfile->name, "ep%u", i);
1770                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1771                                                  epfile,
1772                                                  &ffs_epfile_operations);
1773                 if (unlikely(!epfile->dentry)) {
1774                         ffs_epfiles_destroy(epfiles, i - 1);
1775                         return -ENOMEM;
1776                 }
1777         }
1778
1779         ffs->epfiles = epfiles;
1780         return 0;
1781 }
1782
1783 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1784 {
1785         struct ffs_epfile *epfile = epfiles;
1786
1787         ENTER();
1788
1789         for (; count; --count, ++epfile) {
1790                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1791                        waitqueue_active(&epfile->wait));
1792                 if (epfile->dentry) {
1793                         d_delete(epfile->dentry);
1794                         dput(epfile->dentry);
1795                         epfile->dentry = NULL;
1796                 }
1797         }
1798
1799         kfree(epfiles);
1800 }
1801
1802 static void ffs_func_eps_disable(struct ffs_function *func)
1803 {
1804         struct ffs_ep *ep         = func->eps;
1805         struct ffs_epfile *epfile = func->ffs->epfiles;
1806         unsigned count            = func->ffs->eps_count;
1807         unsigned long flags;
1808
1809         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1810         while (count--) {
1811                 /* pending requests get nuked */
1812                 if (likely(ep->ep))
1813                         usb_ep_disable(ep->ep);
1814                 ++ep;
1815
1816                 if (epfile) {
1817                         epfile->ep = NULL;
1818                         __ffs_epfile_read_buffer_free(epfile);
1819                         ++epfile;
1820                 }
1821         }
1822         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1823 }
1824
1825 static int ffs_func_eps_enable(struct ffs_function *func)
1826 {
1827         struct ffs_data *ffs      = func->ffs;
1828         struct ffs_ep *ep         = func->eps;
1829         struct ffs_epfile *epfile = ffs->epfiles;
1830         unsigned count            = ffs->eps_count;
1831         unsigned long flags;
1832         int ret = 0;
1833
1834         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1835         while(count--) {
1836                 struct usb_endpoint_descriptor *ds;
1837                 struct usb_ss_ep_comp_descriptor *comp_desc = NULL;
1838                 int needs_comp_desc = false;
1839                 int desc_idx;
1840
1841                 if (ffs->gadget->speed == USB_SPEED_SUPER) {
1842                         desc_idx = 2;
1843                         needs_comp_desc = true;
1844                 } else if (ffs->gadget->speed == USB_SPEED_HIGH)
1845                         desc_idx = 1;
1846                 else
1847                         desc_idx = 0;
1848
1849                 /* fall-back to lower speed if desc missing for current speed */
1850                 do {
1851                         ds = ep->descs[desc_idx];
1852                 } while (!ds && --desc_idx >= 0);
1853
1854                 if (!ds) {
1855                         ret = -EINVAL;
1856                         break;
1857                 }
1858
1859                 ep->ep->driver_data = ep;
1860                 ep->ep->desc = ds;
1861
1862                 comp_desc = (struct usb_ss_ep_comp_descriptor *)(ds +
1863                                 USB_DT_ENDPOINT_SIZE);
1864                 ep->ep->maxburst = comp_desc->bMaxBurst + 1;
1865
1866                 if (needs_comp_desc)
1867                         ep->ep->comp_desc = comp_desc;
1868
1869                 ret = usb_ep_enable(ep->ep);
1870                 if (likely(!ret)) {
1871                         epfile->ep = ep;
1872                         epfile->in = usb_endpoint_dir_in(ds);
1873                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1874                 } else {
1875                         break;
1876                 }
1877
1878                 wake_up(&epfile->wait);
1879
1880                 ++ep;
1881                 ++epfile;
1882         }
1883         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1884
1885         return ret;
1886 }
1887
1888
1889 /* Parsing and building descriptors and strings *****************************/
1890
1891 /*
1892  * This validates if data pointed by data is a valid USB descriptor as
1893  * well as record how many interfaces, endpoints and strings are
1894  * required by given configuration.  Returns address after the
1895  * descriptor or NULL if data is invalid.
1896  */
1897
1898 enum ffs_entity_type {
1899         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1900 };
1901
1902 enum ffs_os_desc_type {
1903         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1904 };
1905
1906 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1907                                    u8 *valuep,
1908                                    struct usb_descriptor_header *desc,
1909                                    void *priv);
1910
1911 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1912                                     struct usb_os_desc_header *h, void *data,
1913                                     unsigned len, void *priv);
1914
1915 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1916                                            ffs_entity_callback entity,
1917                                            void *priv)
1918 {
1919         struct usb_descriptor_header *_ds = (void *)data;
1920         u8 length;
1921         int ret;
1922
1923         ENTER();
1924
1925         /* At least two bytes are required: length and type */
1926         if (len < 2) {
1927                 pr_vdebug("descriptor too short\n");
1928                 return -EINVAL;
1929         }
1930
1931         /* If we have at least as many bytes as the descriptor takes? */
1932         length = _ds->bLength;
1933         if (len < length) {
1934                 pr_vdebug("descriptor longer then available data\n");
1935                 return -EINVAL;
1936         }
1937
1938 #define __entity_check_INTERFACE(val)  1
1939 #define __entity_check_STRING(val)     (val)
1940 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1941 #define __entity(type, val) do {                                        \
1942                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1943                 if (unlikely(!__entity_check_ ##type(val))) {           \
1944                         pr_vdebug("invalid entity's value\n");          \
1945                         return -EINVAL;                                 \
1946                 }                                                       \
1947                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1948                 if (unlikely(ret < 0)) {                                \
1949                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1950                                  (val), ret);                           \
1951                         return ret;                                     \
1952                 }                                                       \
1953         } while (0)
1954
1955         /* Parse descriptor depending on type. */
1956         switch (_ds->bDescriptorType) {
1957         case USB_DT_DEVICE:
1958         case USB_DT_CONFIG:
1959         case USB_DT_STRING:
1960         case USB_DT_DEVICE_QUALIFIER:
1961                 /* function can't have any of those */
1962                 pr_vdebug("descriptor reserved for gadget: %d\n",
1963                       _ds->bDescriptorType);
1964                 return -EINVAL;
1965
1966         case USB_DT_INTERFACE: {
1967                 struct usb_interface_descriptor *ds = (void *)_ds;
1968                 pr_vdebug("interface descriptor\n");
1969                 if (length != sizeof *ds)
1970                         goto inv_length;
1971
1972                 __entity(INTERFACE, ds->bInterfaceNumber);
1973                 if (ds->iInterface)
1974                         __entity(STRING, ds->iInterface);
1975         }
1976                 break;
1977
1978         case USB_DT_ENDPOINT: {
1979                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1980                 pr_vdebug("endpoint descriptor\n");
1981                 if (length != USB_DT_ENDPOINT_SIZE &&
1982                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1983                         goto inv_length;
1984                 __entity(ENDPOINT, ds->bEndpointAddress);
1985         }
1986                 break;
1987
1988         case HID_DT_HID:
1989                 pr_vdebug("hid descriptor\n");
1990                 if (length != sizeof(struct hid_descriptor))
1991                         goto inv_length;
1992                 break;
1993
1994         case USB_DT_OTG:
1995                 if (length != sizeof(struct usb_otg_descriptor))
1996                         goto inv_length;
1997                 break;
1998
1999         case USB_DT_INTERFACE_ASSOCIATION: {
2000                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2001                 pr_vdebug("interface association descriptor\n");
2002                 if (length != sizeof *ds)
2003                         goto inv_length;
2004                 if (ds->iFunction)
2005                         __entity(STRING, ds->iFunction);
2006         }
2007                 break;
2008
2009         case USB_DT_SS_ENDPOINT_COMP:
2010                 pr_vdebug("EP SS companion descriptor\n");
2011                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2012                         goto inv_length;
2013                 break;
2014
2015         case USB_DT_OTHER_SPEED_CONFIG:
2016         case USB_DT_INTERFACE_POWER:
2017         case USB_DT_DEBUG:
2018         case USB_DT_SECURITY:
2019         case USB_DT_CS_RADIO_CONTROL:
2020                 /* TODO */
2021                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2022                 return -EINVAL;
2023
2024         default:
2025                 /* We should never be here */
2026                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2027                 return -EINVAL;
2028
2029 inv_length:
2030                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2031                           _ds->bLength, _ds->bDescriptorType);
2032                 return -EINVAL;
2033         }
2034
2035 #undef __entity
2036 #undef __entity_check_DESCRIPTOR
2037 #undef __entity_check_INTERFACE
2038 #undef __entity_check_STRING
2039 #undef __entity_check_ENDPOINT
2040
2041         return length;
2042 }
2043
2044 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2045                                      ffs_entity_callback entity, void *priv)
2046 {
2047         const unsigned _len = len;
2048         unsigned long num = 0;
2049
2050         ENTER();
2051
2052         for (;;) {
2053                 int ret;
2054
2055                 if (num == count)
2056                         data = NULL;
2057
2058                 /* Record "descriptor" entity */
2059                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2060                 if (unlikely(ret < 0)) {
2061                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2062                                  num, ret);
2063                         return ret;
2064                 }
2065
2066                 if (!data)
2067                         return _len - len;
2068
2069                 ret = ffs_do_single_desc(data, len, entity, priv);
2070                 if (unlikely(ret < 0)) {
2071                         pr_debug("%s returns %d\n", __func__, ret);
2072                         return ret;
2073                 }
2074
2075                 len -= ret;
2076                 data += ret;
2077                 ++num;
2078         }
2079 }
2080
2081 static int __ffs_data_do_entity(enum ffs_entity_type type,
2082                                 u8 *valuep, struct usb_descriptor_header *desc,
2083                                 void *priv)
2084 {
2085         struct ffs_desc_helper *helper = priv;
2086         struct usb_endpoint_descriptor *d;
2087
2088         ENTER();
2089
2090         switch (type) {
2091         case FFS_DESCRIPTOR:
2092                 break;
2093
2094         case FFS_INTERFACE:
2095                 /*
2096                  * Interfaces are indexed from zero so if we
2097                  * encountered interface "n" then there are at least
2098                  * "n+1" interfaces.
2099                  */
2100                 if (*valuep >= helper->interfaces_count)
2101                         helper->interfaces_count = *valuep + 1;
2102                 break;
2103
2104         case FFS_STRING:
2105                 /*
2106                  * Strings are indexed from 1 (0 is reserved
2107                  * for languages list)
2108                  */
2109                 if (*valuep > helper->ffs->strings_count)
2110                         helper->ffs->strings_count = *valuep;
2111                 break;
2112
2113         case FFS_ENDPOINT:
2114                 d = (void *)desc;
2115                 helper->eps_count++;
2116                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2117                         return -EINVAL;
2118                 /* Check if descriptors for any speed were already parsed */
2119                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2120                         helper->ffs->eps_addrmap[helper->eps_count] =
2121                                 d->bEndpointAddress;
2122                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2123                                 d->bEndpointAddress)
2124                         return -EINVAL;
2125                 break;
2126         }
2127
2128         return 0;
2129 }
2130
2131 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2132                                    struct usb_os_desc_header *desc)
2133 {
2134         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2135         u16 w_index = le16_to_cpu(desc->wIndex);
2136
2137         if (bcd_version != 1) {
2138                 pr_vdebug("unsupported os descriptors version: %d",
2139                           bcd_version);
2140                 return -EINVAL;
2141         }
2142         switch (w_index) {
2143         case 0x4:
2144                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2145                 break;
2146         case 0x5:
2147                 *next_type = FFS_OS_DESC_EXT_PROP;
2148                 break;
2149         default:
2150                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2151                 return -EINVAL;
2152         }
2153
2154         return sizeof(*desc);
2155 }
2156
2157 /*
2158  * Process all extended compatibility/extended property descriptors
2159  * of a feature descriptor
2160  */
2161 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2162                                               enum ffs_os_desc_type type,
2163                                               u16 feature_count,
2164                                               ffs_os_desc_callback entity,
2165                                               void *priv,
2166                                               struct usb_os_desc_header *h)
2167 {
2168         int ret;
2169         const unsigned _len = len;
2170
2171         ENTER();
2172
2173         /* loop over all ext compat/ext prop descriptors */
2174         while (feature_count--) {
2175                 ret = entity(type, h, data, len, priv);
2176                 if (unlikely(ret < 0)) {
2177                         pr_debug("bad OS descriptor, type: %d\n", type);
2178                         return ret;
2179                 }
2180                 data += ret;
2181                 len -= ret;
2182         }
2183         return _len - len;
2184 }
2185
2186 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2187 static int __must_check ffs_do_os_descs(unsigned count,
2188                                         char *data, unsigned len,
2189                                         ffs_os_desc_callback entity, void *priv)
2190 {
2191         const unsigned _len = len;
2192         unsigned long num = 0;
2193
2194         ENTER();
2195
2196         for (num = 0; num < count; ++num) {
2197                 int ret;
2198                 enum ffs_os_desc_type type;
2199                 u16 feature_count;
2200                 struct usb_os_desc_header *desc = (void *)data;
2201
2202                 if (len < sizeof(*desc))
2203                         return -EINVAL;
2204
2205                 /*
2206                  * Record "descriptor" entity.
2207                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2208                  * Move the data pointer to the beginning of extended
2209                  * compatibilities proper or extended properties proper
2210                  * portions of the data
2211                  */
2212                 if (le32_to_cpu(desc->dwLength) > len)
2213                         return -EINVAL;
2214
2215                 ret = __ffs_do_os_desc_header(&type, desc);
2216                 if (unlikely(ret < 0)) {
2217                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2218                                  num, ret);
2219                         return ret;
2220                 }
2221                 /*
2222                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2223                  */
2224                 feature_count = le16_to_cpu(desc->wCount);
2225                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2226                     (feature_count > 255 || desc->Reserved))
2227                                 return -EINVAL;
2228                 len -= ret;
2229                 data += ret;
2230
2231                 /*
2232                  * Process all function/property descriptors
2233                  * of this Feature Descriptor
2234                  */
2235                 ret = ffs_do_single_os_desc(data, len, type,
2236                                             feature_count, entity, priv, desc);
2237                 if (unlikely(ret < 0)) {
2238                         pr_debug("%s returns %d\n", __func__, ret);
2239                         return ret;
2240                 }
2241
2242                 len -= ret;
2243                 data += ret;
2244         }
2245         return _len - len;
2246 }
2247
2248 /**
2249  * Validate contents of the buffer from userspace related to OS descriptors.
2250  */
2251 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2252                                  struct usb_os_desc_header *h, void *data,
2253                                  unsigned len, void *priv)
2254 {
2255         struct ffs_data *ffs = priv;
2256         u8 length;
2257
2258         ENTER();
2259
2260         switch (type) {
2261         case FFS_OS_DESC_EXT_COMPAT: {
2262                 struct usb_ext_compat_desc *d = data;
2263                 int i;
2264
2265                 if (len < sizeof(*d) ||
2266                     d->bFirstInterfaceNumber >= ffs->interfaces_count ||
2267                     !d->Reserved1)
2268                         return -EINVAL;
2269                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2270                         if (d->Reserved2[i])
2271                                 return -EINVAL;
2272
2273                 length = sizeof(struct usb_ext_compat_desc);
2274         }
2275                 break;
2276         case FFS_OS_DESC_EXT_PROP: {
2277                 struct usb_ext_prop_desc *d = data;
2278                 u32 type, pdl;
2279                 u16 pnl;
2280
2281                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2282                         return -EINVAL;
2283                 length = le32_to_cpu(d->dwSize);
2284                 if (len < length)
2285                         return -EINVAL;
2286                 type = le32_to_cpu(d->dwPropertyDataType);
2287                 if (type < USB_EXT_PROP_UNICODE ||
2288                     type > USB_EXT_PROP_UNICODE_MULTI) {
2289                         pr_vdebug("unsupported os descriptor property type: %d",
2290                                   type);
2291                         return -EINVAL;
2292                 }
2293                 pnl = le16_to_cpu(d->wPropertyNameLength);
2294                 if (length < 14 + pnl) {
2295                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2296                                   length, pnl, type);
2297                         return -EINVAL;
2298                 }
2299                 pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
2300                 if (length != 14 + pnl + pdl) {
2301                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2302                                   length, pnl, pdl, type);
2303                         return -EINVAL;
2304                 }
2305                 ++ffs->ms_os_descs_ext_prop_count;
2306                 /* property name reported to the host as "WCHAR"s */
2307                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2308                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2309         }
2310                 break;
2311         default:
2312                 pr_vdebug("unknown descriptor: %d\n", type);
2313                 return -EINVAL;
2314         }
2315         return length;
2316 }
2317
2318 static int __ffs_data_got_descs(struct ffs_data *ffs,
2319                                 char *const _data, size_t len)
2320 {
2321         char *data = _data, *raw_descs;
2322         unsigned os_descs_count = 0, counts[3], flags;
2323         int ret = -EINVAL, i;
2324         struct ffs_desc_helper helper;
2325
2326         ENTER();
2327
2328         if (get_unaligned_le32(data + 4) != len)
2329                 goto error;
2330
2331         switch (get_unaligned_le32(data)) {
2332         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2333                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2334                 data += 8;
2335                 len  -= 8;
2336                 break;
2337         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2338                 flags = get_unaligned_le32(data + 8);
2339                 ffs->user_flags = flags;
2340                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2341                               FUNCTIONFS_HAS_HS_DESC |
2342                               FUNCTIONFS_HAS_SS_DESC |
2343                               FUNCTIONFS_HAS_MS_OS_DESC |
2344                               FUNCTIONFS_VIRTUAL_ADDR |
2345                               FUNCTIONFS_EVENTFD |
2346                               FUNCTIONFS_ALL_CTRL_RECIP |
2347                               FUNCTIONFS_CONFIG0_SETUP)) {
2348                         ret = -ENOSYS;
2349                         goto error;
2350                 }
2351                 data += 12;
2352                 len  -= 12;
2353                 break;
2354         default:
2355                 goto error;
2356         }
2357
2358         if (flags & FUNCTIONFS_EVENTFD) {
2359                 if (len < 4)
2360                         goto error;
2361                 ffs->ffs_eventfd =
2362                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2363                 if (IS_ERR(ffs->ffs_eventfd)) {
2364                         ret = PTR_ERR(ffs->ffs_eventfd);
2365                         ffs->ffs_eventfd = NULL;
2366                         goto error;
2367                 }
2368                 data += 4;
2369                 len  -= 4;
2370         }
2371
2372         /* Read fs_count, hs_count and ss_count (if present) */
2373         for (i = 0; i < 3; ++i) {
2374                 if (!(flags & (1 << i))) {
2375                         counts[i] = 0;
2376                 } else if (len < 4) {
2377                         goto error;
2378                 } else {
2379                         counts[i] = get_unaligned_le32(data);
2380                         data += 4;
2381                         len  -= 4;
2382                 }
2383         }
2384         if (flags & (1 << i)) {
2385                 if (len < 4) {
2386                         goto error;
2387                 }
2388                 os_descs_count = get_unaligned_le32(data);
2389                 data += 4;
2390                 len -= 4;
2391         };
2392
2393         /* Read descriptors */
2394         raw_descs = data;
2395         helper.ffs = ffs;
2396         for (i = 0; i < 3; ++i) {
2397                 if (!counts[i])
2398                         continue;
2399                 helper.interfaces_count = 0;
2400                 helper.eps_count = 0;
2401                 ret = ffs_do_descs(counts[i], data, len,
2402                                    __ffs_data_do_entity, &helper);
2403                 if (ret < 0)
2404                         goto error;
2405                 if (!ffs->eps_count && !ffs->interfaces_count) {
2406                         ffs->eps_count = helper.eps_count;
2407                         ffs->interfaces_count = helper.interfaces_count;
2408                 } else {
2409                         if (ffs->eps_count != helper.eps_count) {
2410                                 ret = -EINVAL;
2411                                 goto error;
2412                         }
2413                         if (ffs->interfaces_count != helper.interfaces_count) {
2414                                 ret = -EINVAL;
2415                                 goto error;
2416                         }
2417                 }
2418                 data += ret;
2419                 len  -= ret;
2420         }
2421         if (os_descs_count) {
2422                 ret = ffs_do_os_descs(os_descs_count, data, len,
2423                                       __ffs_data_do_os_desc, ffs);
2424                 if (ret < 0)
2425                         goto error;
2426                 data += ret;
2427                 len -= ret;
2428         }
2429
2430         if (raw_descs == data || len) {
2431                 ret = -EINVAL;
2432                 goto error;
2433         }
2434
2435         ffs->raw_descs_data     = _data;
2436         ffs->raw_descs          = raw_descs;
2437         ffs->raw_descs_length   = data - raw_descs;
2438         ffs->fs_descs_count     = counts[0];
2439         ffs->hs_descs_count     = counts[1];
2440         ffs->ss_descs_count     = counts[2];
2441         ffs->ms_os_descs_count  = os_descs_count;
2442
2443         return 0;
2444
2445 error:
2446         kfree(_data);
2447         return ret;
2448 }
2449
2450 static int __ffs_data_got_strings(struct ffs_data *ffs,
2451                                   char *const _data, size_t len)
2452 {
2453         u32 str_count, needed_count, lang_count;
2454         struct usb_gadget_strings **stringtabs, *t;
2455         const char *data = _data;
2456         struct usb_string *s;
2457
2458         ENTER();
2459
2460         if (unlikely(len < 16 ||
2461                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2462                      get_unaligned_le32(data + 4) != len))
2463                 goto error;
2464         str_count  = get_unaligned_le32(data + 8);
2465         lang_count = get_unaligned_le32(data + 12);
2466
2467         /* if one is zero the other must be zero */
2468         if (unlikely(!str_count != !lang_count))
2469                 goto error;
2470
2471         /* Do we have at least as many strings as descriptors need? */
2472         needed_count = ffs->strings_count;
2473         if (unlikely(str_count < needed_count))
2474                 goto error;
2475
2476         /*
2477          * If we don't need any strings just return and free all
2478          * memory.
2479          */
2480         if (!needed_count) {
2481                 kfree(_data);
2482                 return 0;
2483         }
2484
2485         /* Allocate everything in one chunk so there's less maintenance. */
2486         {
2487                 unsigned i = 0;
2488                 vla_group(d);
2489                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2490                         lang_count + 1);
2491                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2492                 vla_item(d, struct usb_string, strings,
2493                         lang_count*(needed_count+1));
2494
2495                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2496
2497                 if (unlikely(!vlabuf)) {
2498                         kfree(_data);
2499                         return -ENOMEM;
2500                 }
2501
2502                 /* Initialize the VLA pointers */
2503                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2504                 t = vla_ptr(vlabuf, d, stringtab);
2505                 i = lang_count;
2506                 do {
2507                         *stringtabs++ = t++;
2508                 } while (--i);
2509                 *stringtabs = NULL;
2510
2511                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2512                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2513                 t = vla_ptr(vlabuf, d, stringtab);
2514                 s = vla_ptr(vlabuf, d, strings);
2515         }
2516
2517         /* For each language */
2518         data += 16;
2519         len -= 16;
2520
2521         do { /* lang_count > 0 so we can use do-while */
2522                 unsigned needed = needed_count;
2523
2524                 if (unlikely(len < 3))
2525                         goto error_free;
2526                 t->language = get_unaligned_le16(data);
2527                 t->strings  = s;
2528                 ++t;
2529
2530                 data += 2;
2531                 len -= 2;
2532
2533                 /* For each string */
2534                 do { /* str_count > 0 so we can use do-while */
2535                         size_t length = strnlen(data, len);
2536
2537                         if (unlikely(length == len))
2538                                 goto error_free;
2539
2540                         /*
2541                          * User may provide more strings then we need,
2542                          * if that's the case we simply ignore the
2543                          * rest
2544                          */
2545                         if (likely(needed)) {
2546                                 /*
2547                                  * s->id will be set while adding
2548                                  * function to configuration so for
2549                                  * now just leave garbage here.
2550                                  */
2551                                 s->s = data;
2552                                 --needed;
2553                                 ++s;
2554                         }
2555
2556                         data += length + 1;
2557                         len -= length + 1;
2558                 } while (--str_count);
2559
2560                 s->id = 0;   /* terminator */
2561                 s->s = NULL;
2562                 ++s;
2563
2564         } while (--lang_count);
2565
2566         /* Some garbage left? */
2567         if (unlikely(len))
2568                 goto error_free;
2569
2570         /* Done! */
2571         ffs->stringtabs = stringtabs;
2572         ffs->raw_strings = _data;
2573
2574         return 0;
2575
2576 error_free:
2577         kfree(stringtabs);
2578 error:
2579         kfree(_data);
2580         return -EINVAL;
2581 }
2582
2583
2584 /* Events handling and management *******************************************/
2585
2586 static void __ffs_event_add(struct ffs_data *ffs,
2587                             enum usb_functionfs_event_type type)
2588 {
2589         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2590         int neg = 0;
2591
2592         /*
2593          * Abort any unhandled setup
2594          *
2595          * We do not need to worry about some cmpxchg() changing value
2596          * of ffs->setup_state without holding the lock because when
2597          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2598          * the source does nothing.
2599          */
2600         if (ffs->setup_state == FFS_SETUP_PENDING)
2601                 ffs->setup_state = FFS_SETUP_CANCELLED;
2602
2603         /*
2604          * Logic of this function guarantees that there are at most four pending
2605          * evens on ffs->ev.types queue.  This is important because the queue
2606          * has space for four elements only and __ffs_ep0_read_events function
2607          * depends on that limit as well.  If more event types are added, those
2608          * limits have to be revisited or guaranteed to still hold.
2609          */
2610         switch (type) {
2611         case FUNCTIONFS_RESUME:
2612                 rem_type2 = FUNCTIONFS_SUSPEND;
2613                 /* FALL THROUGH */
2614         case FUNCTIONFS_SUSPEND:
2615         case FUNCTIONFS_SETUP:
2616                 rem_type1 = type;
2617                 /* Discard all similar events */
2618                 break;
2619
2620         case FUNCTIONFS_BIND:
2621         case FUNCTIONFS_UNBIND:
2622         case FUNCTIONFS_DISABLE:
2623         case FUNCTIONFS_ENABLE:
2624                 /* Discard everything other then power management. */
2625                 rem_type1 = FUNCTIONFS_SUSPEND;
2626                 rem_type2 = FUNCTIONFS_RESUME;
2627                 neg = 1;
2628                 break;
2629
2630         default:
2631                 WARN(1, "%d: unknown event, this should not happen\n", type);
2632                 return;
2633         }
2634
2635         {
2636                 u8 *ev  = ffs->ev.types, *out = ev;
2637                 unsigned n = ffs->ev.count;
2638                 for (; n; --n, ++ev)
2639                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2640                                 *out++ = *ev;
2641                         else
2642                                 pr_vdebug("purging event %d\n", *ev);
2643                 ffs->ev.count = out - ffs->ev.types;
2644         }
2645
2646         pr_vdebug("adding event %d\n", type);
2647         ffs->ev.types[ffs->ev.count++] = type;
2648         wake_up_locked(&ffs->ev.waitq);
2649         if (ffs->ffs_eventfd)
2650                 eventfd_signal(ffs->ffs_eventfd, 1);
2651 }
2652
2653 static void ffs_event_add(struct ffs_data *ffs,
2654                           enum usb_functionfs_event_type type)
2655 {
2656         unsigned long flags;
2657         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2658         __ffs_event_add(ffs, type);
2659         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2660 }
2661
2662 /* Bind/unbind USB function hooks *******************************************/
2663
2664 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2665 {
2666         int i;
2667
2668         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2669                 if (ffs->eps_addrmap[i] == endpoint_address)
2670                         return i;
2671         return -ENOENT;
2672 }
2673
2674 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2675                                     struct usb_descriptor_header *desc,
2676                                     void *priv)
2677 {
2678         struct usb_endpoint_descriptor *ds = (void *)desc;
2679         struct ffs_function *func = priv;
2680         struct ffs_ep *ffs_ep;
2681         unsigned ep_desc_id;
2682         int idx;
2683         static const char *speed_names[] = { "full", "high", "super" };
2684
2685         if (type != FFS_DESCRIPTOR)
2686                 return 0;
2687
2688         /*
2689          * If ss_descriptors is not NULL, we are reading super speed
2690          * descriptors; if hs_descriptors is not NULL, we are reading high
2691          * speed descriptors; otherwise, we are reading full speed
2692          * descriptors.
2693          */
2694         if (func->function.ss_descriptors) {
2695                 ep_desc_id = 2;
2696                 func->function.ss_descriptors[(long)valuep] = desc;
2697         } else if (func->function.hs_descriptors) {
2698                 ep_desc_id = 1;
2699                 func->function.hs_descriptors[(long)valuep] = desc;
2700         } else {
2701                 ep_desc_id = 0;
2702                 func->function.fs_descriptors[(long)valuep]    = desc;
2703         }
2704
2705         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2706                 return 0;
2707
2708         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2709         if (idx < 0)
2710                 return idx;
2711
2712         ffs_ep = func->eps + idx;
2713
2714         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2715                 pr_err("two %sspeed descriptors for EP %d\n",
2716                           speed_names[ep_desc_id],
2717                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2718                 return -EINVAL;
2719         }
2720         ffs_ep->descs[ep_desc_id] = ds;
2721
2722         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2723         if (ffs_ep->ep) {
2724                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2725                 if (!ds->wMaxPacketSize)
2726                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2727         } else {
2728                 struct usb_request *req;
2729                 struct usb_ep *ep;
2730                 u8 bEndpointAddress;
2731
2732                 /*
2733                  * We back up bEndpointAddress because autoconfig overwrites
2734                  * it with physical endpoint address.
2735                  */
2736                 bEndpointAddress = ds->bEndpointAddress;
2737                 pr_vdebug("autoconfig\n");
2738                 ep = usb_ep_autoconfig(func->gadget, ds);
2739                 if (unlikely(!ep))
2740                         return -ENOTSUPP;
2741                 ep->driver_data = func->eps + idx;
2742
2743                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2744                 if (unlikely(!req))
2745                         return -ENOMEM;
2746
2747                 ffs_ep->ep  = ep;
2748                 ffs_ep->req = req;
2749                 func->eps_revmap[ds->bEndpointAddress &
2750                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2751                 /*
2752                  * If we use virtual address mapping, we restore
2753                  * original bEndpointAddress value.
2754                  */
2755                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2756                         ds->bEndpointAddress = bEndpointAddress;
2757         }
2758         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2759
2760         return 0;
2761 }
2762
2763 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2764                                    struct usb_descriptor_header *desc,
2765                                    void *priv)
2766 {
2767         struct ffs_function *func = priv;
2768         unsigned idx;
2769         u8 newValue;
2770
2771         switch (type) {
2772         default:
2773         case FFS_DESCRIPTOR:
2774                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2775                 return 0;
2776
2777         case FFS_INTERFACE:
2778                 idx = *valuep;
2779                 if (func->interfaces_nums[idx] < 0) {
2780                         int id = usb_interface_id(func->conf, &func->function);
2781                         if (unlikely(id < 0))
2782                                 return id;
2783                         func->interfaces_nums[idx] = id;
2784                 }
2785                 newValue = func->interfaces_nums[idx];
2786                 break;
2787
2788         case FFS_STRING:
2789                 /* String' IDs are allocated when fsf_data is bound to cdev */
2790                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2791                 break;
2792
2793         case FFS_ENDPOINT:
2794                 /*
2795                  * USB_DT_ENDPOINT are handled in
2796                  * __ffs_func_bind_do_descs().
2797                  */
2798                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2799                         return 0;
2800
2801                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2802                 if (unlikely(!func->eps[idx].ep))
2803                         return -EINVAL;
2804
2805                 {
2806                         struct usb_endpoint_descriptor **descs;
2807                         descs = func->eps[idx].descs;
2808                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2809                 }
2810                 break;
2811         }
2812
2813         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2814         *valuep = newValue;
2815         return 0;
2816 }
2817
2818 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2819                                       struct usb_os_desc_header *h, void *data,
2820                                       unsigned len, void *priv)
2821 {
2822         struct ffs_function *func = priv;
2823         u8 length = 0;
2824
2825         switch (type) {
2826         case FFS_OS_DESC_EXT_COMPAT: {
2827                 struct usb_ext_compat_desc *desc = data;
2828                 struct usb_os_desc_table *t;
2829
2830                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2831                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2832                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2833                        ARRAY_SIZE(desc->CompatibleID) +
2834                        ARRAY_SIZE(desc->SubCompatibleID));
2835                 length = sizeof(*desc);
2836         }
2837                 break;
2838         case FFS_OS_DESC_EXT_PROP: {
2839                 struct usb_ext_prop_desc *desc = data;
2840                 struct usb_os_desc_table *t;
2841                 struct usb_os_desc_ext_prop *ext_prop;
2842                 char *ext_prop_name;
2843                 char *ext_prop_data;
2844
2845                 t = &func->function.os_desc_table[h->interface];
2846                 t->if_id = func->interfaces_nums[h->interface];
2847
2848                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2849                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2850
2851                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2852                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2853                 ext_prop->data_len = le32_to_cpu(*(u32 *)
2854                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2855                 length = ext_prop->name_len + ext_prop->data_len + 14;
2856
2857                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2858                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2859                         ext_prop->name_len;
2860
2861                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2862                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2863                         ext_prop->data_len;
2864                 memcpy(ext_prop_data,
2865                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2866                        ext_prop->data_len);
2867                 /* unicode data reported to the host as "WCHAR"s */
2868                 switch (ext_prop->type) {
2869                 case USB_EXT_PROP_UNICODE:
2870                 case USB_EXT_PROP_UNICODE_ENV:
2871                 case USB_EXT_PROP_UNICODE_LINK:
2872                 case USB_EXT_PROP_UNICODE_MULTI:
2873                         ext_prop->data_len *= 2;
2874                         break;
2875                 }
2876                 ext_prop->data = ext_prop_data;
2877
2878                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2879                        ext_prop->name_len);
2880                 /* property name reported to the host as "WCHAR"s */
2881                 ext_prop->name_len *= 2;
2882                 ext_prop->name = ext_prop_name;
2883
2884                 t->os_desc->ext_prop_len +=
2885                         ext_prop->name_len + ext_prop->data_len + 14;
2886                 ++t->os_desc->ext_prop_count;
2887                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2888         }
2889                 break;
2890         default:
2891                 pr_vdebug("unknown descriptor: %d\n", type);
2892         }
2893
2894         return length;
2895 }
2896
2897 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2898                                                 struct usb_configuration *c)
2899 {
2900         struct ffs_function *func = ffs_func_from_usb(f);
2901         struct f_fs_opts *ffs_opts =
2902                 container_of(f->fi, struct f_fs_opts, func_inst);
2903         int ret;
2904
2905         ENTER();
2906
2907         /*
2908          * Legacy gadget triggers binding in functionfs_ready_callback,
2909          * which already uses locking; taking the same lock here would
2910          * cause a deadlock.
2911          *
2912          * Configfs-enabled gadgets however do need ffs_dev_lock.
2913          */
2914         if (!ffs_opts->no_configfs)
2915                 ffs_dev_lock();
2916         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2917         func->ffs = ffs_opts->dev->ffs_data;
2918         if (!ffs_opts->no_configfs)
2919                 ffs_dev_unlock();
2920         if (ret)
2921                 return ERR_PTR(ret);
2922
2923         func->conf = c;
2924         func->gadget = c->cdev->gadget;
2925
2926         /*
2927          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2928          * configurations are bound in sequence with list_for_each_entry,
2929          * in each configuration its functions are bound in sequence
2930          * with list_for_each_entry, so we assume no race condition
2931          * with regard to ffs_opts->bound access
2932          */
2933         if (!ffs_opts->refcnt) {
2934                 ret = functionfs_bind(func->ffs, c->cdev);
2935                 if (ret)
2936                         return ERR_PTR(ret);
2937         }
2938         ffs_opts->refcnt++;
2939         func->function.strings = func->ffs->stringtabs;
2940
2941         return ffs_opts;
2942 }
2943
2944 static int _ffs_func_bind(struct usb_configuration *c,
2945                           struct usb_function *f)
2946 {
2947         struct ffs_function *func = ffs_func_from_usb(f);
2948         struct ffs_data *ffs = func->ffs;
2949
2950         const int full = !!func->ffs->fs_descs_count;
2951         const int high = gadget_is_dualspeed(func->gadget) &&
2952                 func->ffs->hs_descs_count;
2953         const int super = gadget_is_superspeed(func->gadget) &&
2954                 func->ffs->ss_descs_count;
2955
2956         int fs_len, hs_len, ss_len, ret, i;
2957         struct ffs_ep *eps_ptr;
2958
2959         /* Make it a single chunk, less management later on */
2960         vla_group(d);
2961         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2962         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2963                 full ? ffs->fs_descs_count + 1 : 0);
2964         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2965                 high ? ffs->hs_descs_count + 1 : 0);
2966         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2967                 super ? ffs->ss_descs_count + 1 : 0);
2968         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2969         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2970                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2971         vla_item_with_sz(d, char[16], ext_compat,
2972                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2973         vla_item_with_sz(d, struct usb_os_desc, os_desc,
2974                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2975         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
2976                          ffs->ms_os_descs_ext_prop_count);
2977         vla_item_with_sz(d, char, ext_prop_name,
2978                          ffs->ms_os_descs_ext_prop_name_len);
2979         vla_item_with_sz(d, char, ext_prop_data,
2980                          ffs->ms_os_descs_ext_prop_data_len);
2981         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2982         char *vlabuf;
2983
2984         ENTER();
2985
2986         /* Has descriptors only for speeds gadget does not support */
2987         if (unlikely(!(full | high | super)))
2988                 return -ENOTSUPP;
2989
2990         /* Allocate a single chunk, less management later on */
2991         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
2992         if (unlikely(!vlabuf))
2993                 return -ENOMEM;
2994
2995         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
2996         ffs->ms_os_descs_ext_prop_name_avail =
2997                 vla_ptr(vlabuf, d, ext_prop_name);
2998         ffs->ms_os_descs_ext_prop_data_avail =
2999                 vla_ptr(vlabuf, d, ext_prop_data);
3000
3001         /* Copy descriptors  */
3002         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3003                ffs->raw_descs_length);
3004
3005         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3006         eps_ptr = vla_ptr(vlabuf, d, eps);
3007         for (i = 0; i < ffs->eps_count; i++)
3008                 eps_ptr[i].num = -1;
3009
3010         /* Save pointers
3011          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3012         */
3013         func->eps             = vla_ptr(vlabuf, d, eps);
3014         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3015
3016         /*
3017          * Go through all the endpoint descriptors and allocate
3018          * endpoints first, so that later we can rewrite the endpoint
3019          * numbers without worrying that it may be described later on.
3020          */
3021         if (likely(full)) {
3022                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3023                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3024                                       vla_ptr(vlabuf, d, raw_descs),
3025                                       d_raw_descs__sz,
3026                                       __ffs_func_bind_do_descs, func);
3027                 if (unlikely(fs_len < 0)) {
3028                         ret = fs_len;
3029                         goto error;
3030                 }
3031         } else {
3032                 fs_len = 0;
3033         }
3034
3035         if (likely(high)) {
3036                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3037                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3038                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3039                                       d_raw_descs__sz - fs_len,
3040                                       __ffs_func_bind_do_descs, func);
3041                 if (unlikely(hs_len < 0)) {
3042                         ret = hs_len;
3043                         goto error;
3044                 }
3045         } else {
3046                 hs_len = 0;
3047         }
3048
3049         if (likely(super)) {
3050                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3051                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3052                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3053                                 d_raw_descs__sz - fs_len - hs_len,
3054                                 __ffs_func_bind_do_descs, func);
3055                 if (unlikely(ss_len < 0)) {
3056                         ret = ss_len;
3057                         goto error;
3058                 }
3059         } else {
3060                 ss_len = 0;
3061         }
3062
3063         /*
3064          * Now handle interface numbers allocation and interface and
3065          * endpoint numbers rewriting.  We can do that in one go
3066          * now.
3067          */
3068         ret = ffs_do_descs(ffs->fs_descs_count +
3069                            (high ? ffs->hs_descs_count : 0) +
3070                            (super ? ffs->ss_descs_count : 0),
3071                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3072                            __ffs_func_bind_do_nums, func);
3073         if (unlikely(ret < 0))
3074                 goto error;
3075
3076         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3077         if (c->cdev->use_os_string) {
3078                 for (i = 0; i < ffs->interfaces_count; ++i) {
3079                         struct usb_os_desc *desc;
3080
3081                         desc = func->function.os_desc_table[i].os_desc =
3082                                 vla_ptr(vlabuf, d, os_desc) +
3083                                 i * sizeof(struct usb_os_desc);
3084                         desc->ext_compat_id =
3085                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3086                         INIT_LIST_HEAD(&desc->ext_prop);
3087                 }
3088                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3089                                       vla_ptr(vlabuf, d, raw_descs) +
3090                                       fs_len + hs_len + ss_len,
3091                                       d_raw_descs__sz - fs_len - hs_len -
3092                                       ss_len,
3093                                       __ffs_func_bind_do_os_desc, func);
3094                 if (unlikely(ret < 0))
3095                         goto error;
3096         }
3097         func->function.os_desc_n =
3098                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3099
3100         /* And we're done */
3101         ffs_event_add(ffs, FUNCTIONFS_BIND);
3102         return 0;
3103
3104 error:
3105         /* XXX Do we need to release all claimed endpoints here? */
3106         return ret;
3107 }
3108
3109 static int ffs_func_bind(struct usb_configuration *c,
3110                          struct usb_function *f)
3111 {
3112         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3113         struct ffs_function *func = ffs_func_from_usb(f);
3114         int ret;
3115
3116         if (IS_ERR(ffs_opts))
3117                 return PTR_ERR(ffs_opts);
3118
3119         ret = _ffs_func_bind(c, f);
3120         if (ret && !--ffs_opts->refcnt)
3121                 functionfs_unbind(func->ffs);
3122
3123         return ret;
3124 }
3125
3126
3127 /* Other USB function hooks *************************************************/
3128
3129 static void ffs_reset_work(struct work_struct *work)
3130 {
3131         struct ffs_data *ffs = container_of(work,
3132                 struct ffs_data, reset_work);
3133         ffs_data_reset(ffs);
3134 }
3135
3136 static int ffs_func_set_alt(struct usb_function *f,
3137                             unsigned interface, unsigned alt)
3138 {
3139         struct ffs_function *func = ffs_func_from_usb(f);
3140         struct ffs_data *ffs = func->ffs;
3141         int ret = 0, intf;
3142
3143         if (alt != (unsigned)-1) {
3144                 intf = ffs_func_revmap_intf(func, interface);
3145                 if (unlikely(intf < 0))
3146                         return intf;
3147         }
3148
3149         if (ffs->func)
3150                 ffs_func_eps_disable(ffs->func);
3151
3152         if (ffs->state == FFS_DEACTIVATED) {
3153                 ffs->state = FFS_CLOSING;
3154                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3155                 schedule_work(&ffs->reset_work);
3156                 return -ENODEV;
3157         }
3158
3159         if (ffs->state != FFS_ACTIVE)
3160                 return -ENODEV;
3161
3162         if (alt == (unsigned)-1) {
3163                 ffs->func = NULL;
3164                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3165                 return 0;
3166         }
3167
3168         ffs->func = func;
3169         ret = ffs_func_eps_enable(func);
3170         if (likely(ret >= 0))
3171                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3172         return ret;
3173 }
3174
3175 static void ffs_func_disable(struct usb_function *f)
3176 {
3177         ffs_func_set_alt(f, 0, (unsigned)-1);
3178 }
3179
3180 static int ffs_func_setup(struct usb_function *f,
3181                           const struct usb_ctrlrequest *creq)
3182 {
3183         struct ffs_function *func = ffs_func_from_usb(f);
3184         struct ffs_data *ffs = func->ffs;
3185         unsigned long flags;
3186         int ret;
3187
3188         ENTER();
3189
3190         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3191         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3192         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3193         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3194         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3195
3196         /*
3197          * Most requests directed to interface go through here
3198          * (notable exceptions are set/get interface) so we need to
3199          * handle them.  All other either handled by composite or
3200          * passed to usb_configuration->setup() (if one is set).  No
3201          * matter, we will handle requests directed to endpoint here
3202          * as well (as it's straightforward).  Other request recipient
3203          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3204          * is being used.
3205          */
3206         if (ffs->state != FFS_ACTIVE)
3207                 return -ENODEV;
3208
3209         switch (creq->bRequestType & USB_RECIP_MASK) {
3210         case USB_RECIP_INTERFACE:
3211                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3212                 if (unlikely(ret < 0))
3213                         return ret;
3214                 break;
3215
3216         case USB_RECIP_ENDPOINT:
3217                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3218                 if (unlikely(ret < 0))
3219                         return ret;
3220                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3221                         ret = func->ffs->eps_addrmap[ret];
3222                 break;
3223
3224         default:
3225                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3226                         ret = le16_to_cpu(creq->wIndex);
3227                 else
3228                         return -EOPNOTSUPP;
3229         }
3230
3231         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3232         ffs->ev.setup = *creq;
3233         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3234         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3235         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3236
3237         return 0;
3238 }
3239
3240 static bool ffs_func_req_match(struct usb_function *f,
3241                                const struct usb_ctrlrequest *creq,
3242                                bool config0)
3243 {
3244         struct ffs_function *func = ffs_func_from_usb(f);
3245
3246         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3247                 return false;
3248
3249         switch (creq->bRequestType & USB_RECIP_MASK) {
3250         case USB_RECIP_INTERFACE:
3251                 return (ffs_func_revmap_intf(func,
3252                                              le16_to_cpu(creq->wIndex)) >= 0);
3253         case USB_RECIP_ENDPOINT:
3254                 return (ffs_func_revmap_ep(func,
3255                                            le16_to_cpu(creq->wIndex)) >= 0);
3256         default:
3257                 return (bool) (func->ffs->user_flags &
3258                                FUNCTIONFS_ALL_CTRL_RECIP);
3259         }
3260 }
3261
3262 static void ffs_func_suspend(struct usb_function *f)
3263 {
3264         ENTER();
3265         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3266 }
3267
3268 static void ffs_func_resume(struct usb_function *f)
3269 {
3270         ENTER();
3271         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3272 }
3273
3274
3275 /* Endpoint and interface numbers reverse mapping ***************************/
3276
3277 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3278 {
3279         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3280         return num ? num : -EDOM;
3281 }
3282
3283 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3284 {
3285         short *nums = func->interfaces_nums;
3286         unsigned count = func->ffs->interfaces_count;
3287
3288         for (; count; --count, ++nums) {
3289                 if (*nums >= 0 && *nums == intf)
3290                         return nums - func->interfaces_nums;
3291         }
3292
3293         return -EDOM;
3294 }
3295
3296
3297 /* Devices management *******************************************************/
3298
3299 static LIST_HEAD(ffs_devices);
3300
3301 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3302 {
3303         struct ffs_dev *dev;
3304
3305         list_for_each_entry(dev, &ffs_devices, entry) {
3306                 if (!dev->name || !name)
3307                         continue;
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 #define MAX_INST_NAME_LEN       40
3384
3385 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3386 {
3387         struct f_fs_opts *opts;
3388         char *ptr;
3389         const char *tmp;
3390         int name_len, ret;
3391
3392         name_len = strlen(name) + 1;
3393         if (name_len > MAX_INST_NAME_LEN)
3394                 return -ENAMETOOLONG;
3395
3396         ptr = kstrndup(name, name_len, GFP_KERNEL);
3397         if (!ptr)
3398                 return -ENOMEM;
3399
3400         opts = to_f_fs_opts(fi);
3401         tmp = NULL;
3402
3403         ffs_dev_lock();
3404
3405         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
3406         ret = _ffs_name_dev(opts->dev, ptr);
3407         if (ret) {
3408                 kfree(ptr);
3409                 ffs_dev_unlock();
3410                 return ret;
3411         }
3412         opts->dev->name_allocated = true;
3413
3414         ffs_dev_unlock();
3415
3416         kfree(tmp);
3417
3418         return 0;
3419 }
3420
3421 static struct usb_function_instance *ffs_alloc_inst(void)
3422 {
3423         struct f_fs_opts *opts;
3424         struct ffs_dev *dev;
3425
3426         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3427         if (!opts)
3428                 return ERR_PTR(-ENOMEM);
3429
3430         opts->func_inst.set_inst_name = ffs_set_inst_name;
3431         opts->func_inst.free_func_inst = ffs_free_inst;
3432         ffs_dev_lock();
3433         dev = _ffs_alloc_dev();
3434         ffs_dev_unlock();
3435         if (IS_ERR(dev)) {
3436                 kfree(opts);
3437                 return ERR_CAST(dev);
3438         }
3439         opts->dev = dev;
3440         dev->opts = opts;
3441
3442         config_group_init_type_name(&opts->func_inst.group, "",
3443                                     &ffs_func_type);
3444         return &opts->func_inst;
3445 }
3446
3447 static void ffs_free(struct usb_function *f)
3448 {
3449         kfree(ffs_func_from_usb(f));
3450 }
3451
3452 static void ffs_func_unbind(struct usb_configuration *c,
3453                             struct usb_function *f)
3454 {
3455         struct ffs_function *func = ffs_func_from_usb(f);
3456         struct ffs_data *ffs = func->ffs;
3457         struct f_fs_opts *opts =
3458                 container_of(f->fi, struct f_fs_opts, func_inst);
3459         struct ffs_ep *ep = func->eps;
3460         unsigned count = ffs->eps_count;
3461         unsigned long flags;
3462
3463         ENTER();
3464         if (ffs->func == func) {
3465                 ffs_func_eps_disable(func);
3466                 ffs->func = NULL;
3467         }
3468
3469         if (!--opts->refcnt)
3470                 functionfs_unbind(ffs);
3471
3472         /* cleanup after autoconfig */
3473         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3474         while (count--) {
3475                 if (ep->ep && ep->req)
3476                         usb_ep_free_request(ep->ep, ep->req);
3477                 ep->req = NULL;
3478                 ++ep;
3479         }
3480         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3481         kfree(func->eps);
3482         func->eps = NULL;
3483         /*
3484          * eps, descriptors and interfaces_nums are allocated in the
3485          * same chunk so only one free is required.
3486          */
3487         func->function.fs_descriptors = NULL;
3488         func->function.hs_descriptors = NULL;
3489         func->function.ss_descriptors = NULL;
3490         func->interfaces_nums = NULL;
3491
3492         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3493 }
3494
3495 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3496 {
3497         struct ffs_function *func;
3498
3499         ENTER();
3500
3501         func = kzalloc(sizeof(*func), GFP_KERNEL);
3502         if (unlikely(!func))
3503                 return ERR_PTR(-ENOMEM);
3504
3505         func->function.name    = "Function FS Gadget";
3506
3507         func->function.bind    = ffs_func_bind;
3508         func->function.unbind  = ffs_func_unbind;
3509         func->function.set_alt = ffs_func_set_alt;
3510         func->function.disable = ffs_func_disable;
3511         func->function.setup   = ffs_func_setup;
3512         func->function.req_match = ffs_func_req_match;
3513         func->function.suspend = ffs_func_suspend;
3514         func->function.resume  = ffs_func_resume;
3515         func->function.free_func = ffs_free;
3516
3517         return &func->function;
3518 }
3519
3520 /*
3521  * ffs_lock must be taken by the caller of this function
3522  */
3523 static struct ffs_dev *_ffs_alloc_dev(void)
3524 {
3525         struct ffs_dev *dev;
3526         int ret;
3527
3528         if (_ffs_get_single_dev())
3529                         return ERR_PTR(-EBUSY);
3530
3531         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3532         if (!dev)
3533                 return ERR_PTR(-ENOMEM);
3534
3535         if (list_empty(&ffs_devices)) {
3536                 ret = functionfs_init();
3537                 if (ret) {
3538                         kfree(dev);
3539                         return ERR_PTR(ret);
3540                 }
3541         }
3542
3543         list_add(&dev->entry, &ffs_devices);
3544
3545         return dev;
3546 }
3547
3548 /*
3549  * ffs_lock must be taken by the caller of this function
3550  * The caller is responsible for "name" being available whenever f_fs needs it
3551  */
3552 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
3553 {
3554         struct ffs_dev *existing;
3555
3556         existing = _ffs_do_find_dev(name);
3557         if (existing)
3558                 return -EBUSY;
3559
3560         dev->name = name;
3561
3562         return 0;
3563 }
3564
3565 /*
3566  * The caller is responsible for "name" being available whenever f_fs needs it
3567  */
3568 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3569 {
3570         int ret;
3571
3572         ffs_dev_lock();
3573         ret = _ffs_name_dev(dev, name);
3574         ffs_dev_unlock();
3575
3576         return ret;
3577 }
3578 EXPORT_SYMBOL_GPL(ffs_name_dev);
3579
3580 int ffs_single_dev(struct ffs_dev *dev)
3581 {
3582         int ret;
3583
3584         ret = 0;
3585         ffs_dev_lock();
3586
3587         if (!list_is_singular(&ffs_devices))
3588                 ret = -EBUSY;
3589         else
3590                 dev->single = true;
3591
3592         ffs_dev_unlock();
3593         return ret;
3594 }
3595 EXPORT_SYMBOL_GPL(ffs_single_dev);
3596
3597 /*
3598  * ffs_lock must be taken by the caller of this function
3599  */
3600 static void _ffs_free_dev(struct ffs_dev *dev)
3601 {
3602         list_del(&dev->entry);
3603         if (dev->name_allocated)
3604                 kfree(dev->name);
3605
3606         /* Clear the private_data pointer to stop incorrect dev access */
3607         if (dev->ffs_data)
3608                 dev->ffs_data->private_data = NULL;
3609
3610         kfree(dev);
3611         if (list_empty(&ffs_devices))
3612                 functionfs_cleanup();
3613 }
3614
3615 static void *ffs_acquire_dev(const char *dev_name)
3616 {
3617         struct ffs_dev *ffs_dev;
3618
3619         ENTER();
3620         ffs_dev_lock();
3621
3622         ffs_dev = _ffs_find_dev(dev_name);
3623         if (!ffs_dev)
3624                 ffs_dev = ERR_PTR(-ENOENT);
3625         else if (ffs_dev->mounted)
3626                 ffs_dev = ERR_PTR(-EBUSY);
3627         else if (ffs_dev->ffs_acquire_dev_callback &&
3628             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3629                 ffs_dev = ERR_PTR(-ENOENT);
3630         else
3631                 ffs_dev->mounted = true;
3632
3633         ffs_dev_unlock();
3634         return ffs_dev;
3635 }
3636
3637 static void ffs_release_dev(struct ffs_data *ffs_data)
3638 {
3639         struct ffs_dev *ffs_dev;
3640
3641         ENTER();
3642         ffs_dev_lock();
3643
3644         ffs_dev = ffs_data->private_data;
3645         if (ffs_dev) {
3646                 ffs_dev->mounted = false;
3647
3648                 if (ffs_dev->ffs_release_dev_callback)
3649                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3650         }
3651
3652         ffs_dev_unlock();
3653 }
3654
3655 static int ffs_ready(struct ffs_data *ffs)
3656 {
3657         struct ffs_dev *ffs_obj;
3658         int ret = 0;
3659
3660         ENTER();
3661         ffs_dev_lock();
3662
3663         ffs_obj = ffs->private_data;
3664         if (!ffs_obj) {
3665                 ret = -EINVAL;
3666                 goto done;
3667         }
3668         if (WARN_ON(ffs_obj->desc_ready)) {
3669                 ret = -EBUSY;
3670                 goto done;
3671         }
3672
3673         ffs_obj->desc_ready = true;
3674         ffs_obj->ffs_data = ffs;
3675
3676         if (ffs_obj->ffs_ready_callback) {
3677                 ret = ffs_obj->ffs_ready_callback(ffs);
3678                 if (ret)
3679                         goto done;
3680         }
3681
3682         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3683 done:
3684         ffs_dev_unlock();
3685         return ret;
3686 }
3687
3688 static void ffs_closed(struct ffs_data *ffs)
3689 {
3690         struct ffs_dev *ffs_obj;
3691         struct f_fs_opts *opts;
3692         struct config_item *ci;
3693
3694         ENTER();
3695         ffs_dev_lock();
3696
3697         ffs_obj = ffs->private_data;
3698         if (!ffs_obj)
3699                 goto done;
3700
3701         ffs_obj->desc_ready = false;
3702
3703         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3704             ffs_obj->ffs_closed_callback)
3705                 ffs_obj->ffs_closed_callback(ffs);
3706
3707         if (ffs_obj->opts)
3708                 opts = ffs_obj->opts;
3709         else
3710                 goto done;
3711
3712         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3713             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3714                 goto done;
3715
3716         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3717         ffs_dev_unlock();
3718
3719         unregister_gadget_item(ci);
3720         return;
3721 done:
3722         ffs_dev_unlock();
3723 }
3724
3725 /* Misc helper functions ****************************************************/
3726
3727 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3728 {
3729         return nonblock
3730                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3731                 : mutex_lock_interruptible(mutex);
3732 }
3733
3734 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3735 {
3736         char *data;
3737
3738         if (unlikely(!len))
3739                 return NULL;
3740
3741         data = kmalloc(len, GFP_KERNEL);
3742         if (unlikely(!data))
3743                 return ERR_PTR(-ENOMEM);
3744
3745         if (unlikely(copy_from_user(data, buf, len))) {
3746                 kfree(data);
3747                 return ERR_PTR(-EFAULT);
3748         }
3749
3750         pr_vdebug("Buffer from user space:\n");
3751         ffs_dump_mem("", data, len);
3752
3753         return data;
3754 }
3755
3756 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3757 MODULE_LICENSE("GPL");
3758 MODULE_AUTHOR("Michal Nazarewicz");