drivers/usb/gadget/function/f_fs.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_fs.c -- user mode file system API for USB composite function controllers
   4  *
   5  * Copyright (C) 2010 Samsung Electronics
   6  * Author: Michal Nazarewicz <mina86@mina86.com>
   7  *
   8  * Based on inode.c (GadgetFS) which was:
   9  * Copyright (C) 2003-2004 David Brownell
  10  * Copyright (C) 2003 Agilent Technologies
  11  */
  12
  13
  14 /* #define DEBUG */
  15 /* #define VERBOSE_DEBUG */
  16
  17 #include <linux/blkdev.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/export.h>
  20 #include <linux/hid.h>
  21 #include <linux/module.h>
  22 #include <linux/sched/signal.h>
  23 #include <linux/uio.h>
  24 #include <asm/unaligned.h>
  25
  26 #include <linux/usb/composite.h>
  27 #include <linux/usb/functionfs.h>
  28
  29 #include <linux/aio.h>
  30 #include <linux/mmu_context.h>
  31 #include <linux/poll.h>
  32 #include <linux/eventfd.h>
  33
  34 #include "u_fs.h"
  35 #include "u_f.h"
  36 #include "u_os_desc.h"
  37 #include "configfs.h"
  38
  39 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  40
  41 /* Reference counter handling */
  42 static void ffs_data_get(struct ffs_data *ffs);
  43 static void ffs_data_put(struct ffs_data *ffs);
  44 /* Creates new ffs_data object. */
  45 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  46         __attribute__((malloc));
  47
  48 /* Opened counter handling. */
  49 static void ffs_data_opened(struct ffs_data *ffs);
  50 static void ffs_data_closed(struct ffs_data *ffs);
  51
  52 /* Called with ffs->mutex held; take over ownership of data. */
  53 static int __must_check
  54 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  55 static int __must_check
  56 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  57
  58
  59 /* The function structure ***************************************************/
  60
  61 struct ffs_ep;
  62
  63 struct ffs_function {
  64         struct usb_configuration        *conf;
  65         struct usb_gadget               *gadget;
  66         struct ffs_data                 *ffs;
  67
  68         struct ffs_ep                   *eps;
  69         u8                              eps_revmap[16];
  70         short                           *interfaces_nums;
  71
  72         struct usb_function             function;
  73 };
  74
  75
  76 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  77 {
  78         return container_of(f, struct ffs_function, function);
  79 }
  80
  81
  82 static inline enum ffs_setup_state
  83 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  84 {
  85         return (enum ffs_setup_state)
  86                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  87 }
  88
  89
  90 static void ffs_func_eps_disable(struct ffs_function *func);
  91 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  92
  93 static int ffs_func_bind(struct usb_configuration *,
  94                          struct usb_function *);
  95 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
  96 static void ffs_func_disable(struct usb_function *);
  97 static int ffs_func_setup(struct usb_function *,
  98                           const struct usb_ctrlrequest *);
  99 static bool ffs_func_req_match(struct usb_function *,
 100                                const struct usb_ctrlrequest *,
 101                                bool config0);
 102 static void ffs_func_suspend(struct usb_function *);
 103 static void ffs_func_resume(struct usb_function *);
 104
 105
 106 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 107 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 108
 109
 110 /* The endpoints structures *************************************************/
 111
 112 struct ffs_ep {
 113         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 114         struct usb_request              *req;   /* P: epfile->mutex */
 115
 116         /* [0]: full speed, [1]: high speed, [2]: super speed */
 117         struct usb_endpoint_descriptor  *descs[3];
 118
 119         u8                              num;
 120
 121         int                             status; /* P: epfile->mutex */
 122 };
 123
 124 struct ffs_epfile {
 125         /* Protects ep->ep and ep->req. */
 126         struct mutex                    mutex;
 127
 128         struct ffs_data                 *ffs;
 129         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 130
 131         struct dentry                   *dentry;
 132
 133         /*
 134          * Buffer for holding data from partial reads which may happen since
 135          * we’re rounding user read requests to a multiple of a max packet size.
 136          *
 137          * The pointer is initialised with NULL value and may be set by
 138          * __ffs_epfile_read_data function to point to a temporary buffer.
 139          *
 140          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 141          * data from said buffer and eventually free it.  Importantly, while the
 142          * function is using the buffer, it sets the pointer to NULL.  This is
 143          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 144          * can never run concurrently (they are synchronised by epfile->mutex)
 145          * so the latter will not assign a new value to the pointer.
 146          *
 147          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 148          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 149          * value is crux of the synchronisation between ffs_func_eps_disable and
 150          * __ffs_epfile_read_data.
 151          *
 152          * Once __ffs_epfile_read_data is about to finish it will try to set the
 153          * pointer back to its old value (as described above), but seeing as the
 154          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 155          * the buffer.
 156          *
 157          * == State transitions ==
 158          *
 159          * • ptr == NULL:  (initial state)
 160          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 161          *   ◦ __ffs_epfile_read_buffered:    nop
 162          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 163          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 164          * • ptr == DROP:
 165          *   ◦ __ffs_epfile_read_buffer_free: nop
 166          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 167          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 168          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 169          * • ptr == buf:
 170          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 171          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 172          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 173          *                                    is always called first
 174          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 175          * • ptr == NULL and reading:
 176          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 177          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 178          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 179          *   ◦ reading finishes and …
 180          *     … all data read:               free buf, go to ptr == NULL
 181          *     … otherwise:                   go to ptr == buf and reading
 182          * • ptr == DROP and reading:
 183          *   ◦ __ffs_epfile_read_buffer_free: nop
 184          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 185          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 186          *   ◦ reading finishes:              free buf, go to ptr == DROP
 187          */
 188         struct ffs_buffer               *read_buffer;
 189 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 190
 191         char                            name[5];
 192
 193         unsigned char                   in;     /* P: ffs->eps_lock */
 194         unsigned char                   isoc;   /* P: ffs->eps_lock */
 195
 196         unsigned char                   _pad;
 197 };
 198
 199 struct ffs_buffer {
 200         size_t length;
 201         char *data;
 202         char storage[];
 203 };
 204
 205 /*  ffs_io_data structure ***************************************************/
 206
 207 struct ffs_io_data {
 208         bool aio;
 209         bool read;
 210
 211         struct kiocb *kiocb;
 212         struct iov_iter data;
 213         const void *to_free;
 214         char *buf;
 215
 216         struct mm_struct *mm;
 217         struct work_struct work;
 218         struct work_struct cancellation_work;
 219
 220         struct usb_ep *ep;
 221         struct usb_request *req;
 222
 223         struct ffs_data *ffs;
 224 };
 225
 226 struct ffs_desc_helper {
 227         struct ffs_data *ffs;
 228         unsigned interfaces_count;
 229         unsigned eps_count;
 230 };
 231
 232 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 233 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 234
 235 static struct dentry *
 236 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 237                    const struct file_operations *fops);
 238
 239 /* Devices management *******************************************************/
 240
 241 DEFINE_MUTEX(ffs_lock);
 242 EXPORT_SYMBOL_GPL(ffs_lock);
 243
 244 static struct ffs_dev *_ffs_find_dev(const char *name);
 245 static struct ffs_dev *_ffs_alloc_dev(void);
 246 static void _ffs_free_dev(struct ffs_dev *dev);
 247 static void *ffs_acquire_dev(const char *dev_name);
 248 static void ffs_release_dev(struct ffs_data *ffs_data);
 249 static int ffs_ready(struct ffs_data *ffs);
 250 static void ffs_closed(struct ffs_data *ffs);
 251
 252 /* Misc helper functions ****************************************************/
 253
 254 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 255         __attribute__((warn_unused_result, nonnull));
 256 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 257         __attribute__((warn_unused_result, nonnull));
 258
 259
 260 /* Control file aka ep0 *****************************************************/
 261
 262 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 263 {
 264         struct ffs_data *ffs = req->context;
 265
 266         complete(&ffs->ep0req_completion);
 267 }
 268
 269 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 270         __releases(&ffs->ev.waitq.lock)
 271 {
 272         struct usb_request *req = ffs->ep0req;
 273         int ret;
 274
 275         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 276
 277         spin_unlock_irq(&ffs->ev.waitq.lock);
 278
 279         req->buf      = data;
 280         req->length   = len;
 281
 282         /*
 283          * UDC layer requires to provide a buffer even for ZLP, but should
 284          * not use it at all. Let's provide some poisoned pointer to catch
 285          * possible bug in the driver.
 286          */
 287         if (req->buf == NULL)
 288                 req->buf = (void *)0xDEADBABE;
 289
 290         reinit_completion(&ffs->ep0req_completion);
 291
 292         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 293         if (unlikely(ret < 0))
 294                 return ret;
 295
 296         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 297         if (unlikely(ret)) {
 298                 usb_ep_dequeue(ffs->gadget->ep0, req);
 299                 return -EINTR;
 300         }
 301
 302         ffs->setup_state = FFS_NO_SETUP;
 303         return req->status ? req->status : req->actual;
 304 }
 305
 306 static int __ffs_ep0_stall(struct ffs_data *ffs)
 307 {
 308         if (ffs->ev.can_stall) {
 309                 pr_vdebug("ep0 stall\n");
 310                 usb_ep_set_halt(ffs->gadget->ep0);
 311                 ffs->setup_state = FFS_NO_SETUP;
 312                 return -EL2HLT;
 313         } else {
 314                 pr_debug("bogus ep0 stall!\n");
 315                 return -ESRCH;
 316         }
 317 }
 318
 319 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 320                              size_t len, loff_t *ptr)
 321 {
 322         struct ffs_data *ffs = file->private_data;
 323         ssize_t ret;
 324         char *data;
 325
 326         ENTER();
 327
 328         /* Fast check if setup was canceled */
 329         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 330                 return -EIDRM;
 331
 332         /* Acquire mutex */
 333         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 334         if (unlikely(ret < 0))
 335                 return ret;
 336
 337         /* Check state */
 338         switch (ffs->state) {
 339         case FFS_READ_DESCRIPTORS:
 340         case FFS_READ_STRINGS:
 341                 /* Copy data */
 342                 if (unlikely(len < 16)) {
 343                         ret = -EINVAL;
 344                         break;
 345                 }
 346
 347                 data = ffs_prepare_buffer(buf, len);
 348                 if (IS_ERR(data)) {
 349                         ret = PTR_ERR(data);
 350                         break;
 351                 }
 352
 353                 /* Handle data */
 354                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 355                         pr_info("read descriptors\n");
 356                         ret = __ffs_data_got_descs(ffs, data, len);
 357                         if (unlikely(ret < 0))
 358                                 break;
 359
 360                         ffs->state = FFS_READ_STRINGS;
 361                         ret = len;
 362                 } else {
 363                         pr_info("read strings\n");
 364                         ret = __ffs_data_got_strings(ffs, data, len);
 365                         if (unlikely(ret < 0))
 366                                 break;
 367
 368                         ret = ffs_epfiles_create(ffs);
 369                         if (unlikely(ret)) {
 370                                 ffs->state = FFS_CLOSING;
 371                                 break;
 372                         }
 373
 374                         ffs->state = FFS_ACTIVE;
 375                         mutex_unlock(&ffs->mutex);
 376
 377                         ret = ffs_ready(ffs);
 378                         if (unlikely(ret < 0)) {
 379                                 ffs->state = FFS_CLOSING;
 380                                 return ret;
 381                         }
 382
 383                         return len;
 384                 }
 385                 break;
 386
 387         case FFS_ACTIVE:
 388                 data = NULL;
 389                 /*
 390                  * We're called from user space, we can use _irq
 391                  * rather then _irqsave
 392                  */
 393                 spin_lock_irq(&ffs->ev.waitq.lock);
 394                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 395                 case FFS_SETUP_CANCELLED:
 396                         ret = -EIDRM;
 397                         goto done_spin;
 398
 399                 case FFS_NO_SETUP:
 400                         ret = -ESRCH;
 401                         goto done_spin;
 402
 403                 case FFS_SETUP_PENDING:
 404                         break;
 405                 }
 406
 407                 /* FFS_SETUP_PENDING */
 408                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 409                         spin_unlock_irq(&ffs->ev.waitq.lock);
 410                         ret = __ffs_ep0_stall(ffs);
 411                         break;
 412                 }
 413
 414                 /* FFS_SETUP_PENDING and not stall */
 415                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 416
 417                 spin_unlock_irq(&ffs->ev.waitq.lock);
 418
 419                 data = ffs_prepare_buffer(buf, len);
 420                 if (IS_ERR(data)) {
 421                         ret = PTR_ERR(data);
 422                         break;
 423                 }
 424
 425                 spin_lock_irq(&ffs->ev.waitq.lock);
 426
 427                 /*
 428                  * We are guaranteed to be still in FFS_ACTIVE state
 429                  * but the state of setup could have changed from
 430                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 431                  * to check for that.  If that happened we copied data
 432                  * from user space in vain but it's unlikely.
 433                  *
 434                  * For sure we are not in FFS_NO_SETUP since this is
 435                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 436                  * transition can be performed and it's protected by
 437                  * mutex.
 438                  */
 439                 if (ffs_setup_state_clear_cancelled(ffs) ==
 440                     FFS_SETUP_CANCELLED) {
 441                         ret = -EIDRM;
 442 done_spin:
 443                         spin_unlock_irq(&ffs->ev.waitq.lock);
 444                 } else {
 445                         /* unlocks spinlock */
 446                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 447                 }
 448                 kfree(data);
 449                 break;
 450
 451         default:
 452                 ret = -EBADFD;
 453                 break;
 454         }
 455
 456         mutex_unlock(&ffs->mutex);
 457         return ret;
 458 }
 459
 460 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 461 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 462                                      size_t n)
 463         __releases(&ffs->ev.waitq.lock)
 464 {
 465         /*
 466          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 467          * size of ffs->ev.types array (which is four) so that's how much space
 468          * we reserve.
 469          */
 470         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 471         const size_t size = n * sizeof *events;
 472         unsigned i = 0;
 473
 474         memset(events, 0, size);
 475
 476         do {
 477                 events[i].type = ffs->ev.types[i];
 478                 if (events[i].type == FUNCTIONFS_SETUP) {
 479                         events[i].u.setup = ffs->ev.setup;
 480                         ffs->setup_state = FFS_SETUP_PENDING;
 481                 }
 482         } while (++i < n);
 483
 484         ffs->ev.count -= n;
 485         if (ffs->ev.count)
 486                 memmove(ffs->ev.types, ffs->ev.types + n,
 487                         ffs->ev.count * sizeof *ffs->ev.types);
 488
 489         spin_unlock_irq(&ffs->ev.waitq.lock);
 490         mutex_unlock(&ffs->mutex);
 491
 492         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 493 }
 494
 495 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 496                             size_t len, loff_t *ptr)
 497 {
 498         struct ffs_data *ffs = file->private_data;
 499         char *data = NULL;
 500         size_t n;
 501         int ret;
 502
 503         ENTER();
 504
 505         /* Fast check if setup was canceled */
 506         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 507                 return -EIDRM;
 508
 509         /* Acquire mutex */
 510         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 511         if (unlikely(ret < 0))
 512                 return ret;
 513
 514         /* Check state */
 515         if (ffs->state != FFS_ACTIVE) {
 516                 ret = -EBADFD;
 517                 goto done_mutex;
 518         }
 519
 520         /*
 521          * We're called from user space, we can use _irq rather then
 522          * _irqsave
 523          */
 524         spin_lock_irq(&ffs->ev.waitq.lock);
 525
 526         switch (ffs_setup_state_clear_cancelled(ffs)) {
 527         case FFS_SETUP_CANCELLED:
 528                 ret = -EIDRM;
 529                 break;
 530
 531         case FFS_NO_SETUP:
 532                 n = len / sizeof(struct usb_functionfs_event);
 533                 if (unlikely(!n)) {
 534                         ret = -EINVAL;
 535                         break;
 536                 }
 537
 538                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 539                         ret = -EAGAIN;
 540                         break;
 541                 }
 542
 543                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 544                                                         ffs->ev.count)) {
 545                         ret = -EINTR;
 546                         break;
 547                 }
 548
 549                 /* unlocks spinlock */
 550                 return __ffs_ep0_read_events(ffs, buf,
 551                                              min(n, (size_t)ffs->ev.count));
 552
 553         case FFS_SETUP_PENDING:
 554                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 555                         spin_unlock_irq(&ffs->ev.waitq.lock);
 556                         ret = __ffs_ep0_stall(ffs);
 557                         goto done_mutex;
 558                 }
 559
 560                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 561
 562                 spin_unlock_irq(&ffs->ev.waitq.lock);
 563
 564                 if (likely(len)) {
 565                         data = kmalloc(len, GFP_KERNEL);
 566                         if (unlikely(!data)) {
 567                                 ret = -ENOMEM;
 568                                 goto done_mutex;
 569                         }
 570                 }
 571
 572                 spin_lock_irq(&ffs->ev.waitq.lock);
 573
 574                 /* See ffs_ep0_write() */
 575                 if (ffs_setup_state_clear_cancelled(ffs) ==
 576                     FFS_SETUP_CANCELLED) {
 577                         ret = -EIDRM;
 578                         break;
 579                 }
 580
 581                 /* unlocks spinlock */
 582                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 583                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 584                         ret = -EFAULT;
 585                 goto done_mutex;
 586
 587         default:
 588                 ret = -EBADFD;
 589                 break;
 590         }
 591
 592         spin_unlock_irq(&ffs->ev.waitq.lock);
 593 done_mutex:
 594         mutex_unlock(&ffs->mutex);
 595         kfree(data);
 596         return ret;
 597 }
 598
 599 static int ffs_ep0_open(struct inode *inode, struct file *file)
 600 {
 601         struct ffs_data *ffs = inode->i_private;
 602
 603         ENTER();
 604
 605         if (unlikely(ffs->state == FFS_CLOSING))
 606                 return -EBUSY;
 607
 608         file->private_data = ffs;
 609         ffs_data_opened(ffs);
 610
 611         return 0;
 612 }
 613
 614 static int ffs_ep0_release(struct inode *inode, struct file *file)
 615 {
 616         struct ffs_data *ffs = file->private_data;
 617
 618         ENTER();
 619
 620         ffs_data_closed(ffs);
 621
 622         return 0;
 623 }
 624
 625 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 626 {
 627         struct ffs_data *ffs = file->private_data;
 628         struct usb_gadget *gadget = ffs->gadget;
 629         long ret;
 630
 631         ENTER();
 632
 633         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 634                 struct ffs_function *func = ffs->func;
 635                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 636         } else if (gadget && gadget->ops->ioctl) {
 637                 ret = gadget->ops->ioctl(gadget, code, value);
 638         } else {
 639                 ret = -ENOTTY;
 640         }
 641
 642         return ret;
 643 }
 644
 645 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 646 {
 647         struct ffs_data *ffs = file->private_data;
 648         __poll_t mask = EPOLLWRNORM;
 649         int ret;
 650
 651         poll_wait(file, &ffs->ev.waitq, wait);
 652
 653         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 654         if (unlikely(ret < 0))
 655                 return mask;
 656
 657         switch (ffs->state) {
 658         case FFS_READ_DESCRIPTORS:
 659         case FFS_READ_STRINGS:
 660                 mask |= EPOLLOUT;
 661                 break;
 662
 663         case FFS_ACTIVE:
 664                 switch (ffs->setup_state) {
 665                 case FFS_NO_SETUP:
 666                         if (ffs->ev.count)
 667                                 mask |= EPOLLIN;
 668                         break;
 669
 670                 case FFS_SETUP_PENDING:
 671                 case FFS_SETUP_CANCELLED:
 672                         mask |= (EPOLLIN | EPOLLOUT);
 673                         break;
 674                 }
 675         case FFS_CLOSING:
 676                 break;
 677         case FFS_DEACTIVATED:
 678                 break;
 679         }
 680
 681         mutex_unlock(&ffs->mutex);
 682
 683         return mask;
 684 }
 685
 686 static const struct file_operations ffs_ep0_operations = {
 687         .llseek =       no_llseek,
 688
 689         .open =         ffs_ep0_open,
 690         .write =        ffs_ep0_write,
 691         .read =         ffs_ep0_read,
 692         .release =      ffs_ep0_release,
 693         .unlocked_ioctl =       ffs_ep0_ioctl,
 694         .poll =         ffs_ep0_poll,
 695 };
 696
 697
 698 /* "Normal" endpoints operations ********************************************/
 699
 700 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 701 {
 702         ENTER();
 703         if (likely(req->context)) {
 704                 struct ffs_ep *ep = _ep->driver_data;
 705                 ep->status = req->status ? req->status : req->actual;
 706                 complete(req->context);
 707         }
 708 }
 709
 710 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 711 {
 712         ssize_t ret = copy_to_iter(data, data_len, iter);
 713         if (likely(ret == data_len))
 714                 return ret;
 715
 716         if (unlikely(iov_iter_count(iter)))
 717                 return -EFAULT;
 718
 719         /*
 720          * Dear user space developer!
 721          *
 722          * TL;DR: To stop getting below error message in your kernel log, change
 723          * user space code using functionfs to align read buffers to a max
 724          * packet size.
 725          *
 726          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 727          * packet size.  When unaligned buffer is passed to functionfs, it
 728          * internally uses a larger, aligned buffer so that such UDCs are happy.
 729          *
 730          * Unfortunately, this means that host may send more data than was
 731          * requested in read(2) system call.  f_fs doesn’t know what to do with
 732          * that excess data so it simply drops it.
 733          *
 734          * Was the buffer aligned in the first place, no such problem would
 735          * happen.
 736          *
 737          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 738          * by splitting a request into multiple parts.  This splitting may still
 739          * be a problem though so it’s likely best to align the buffer
 740          * regardless of it being AIO or not..
 741          *
 742          * This only affects OUT endpoints, i.e. reading data with a read(2),
 743          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 744          * affected.
 745          */
 746         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 747                "Align read buffer size to max packet size to avoid the problem.\n",
 748                data_len, ret);
 749
 750         return ret;
 751 }
 752
 753 static void ffs_user_copy_worker(struct work_struct *work)
 754 {
 755         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 756                                                    work);
 757         int ret = io_data->req->status ? io_data->req->status :
 758                                          io_data->req->actual;
 759         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 760
 761         if (io_data->read && ret > 0) {
 762                 mm_segment_t oldfs = get_fs();
 763
 764                 set_fs(USER_DS);
 765                 use_mm(io_data->mm);
 766                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 767                 unuse_mm(io_data->mm);
 768                 set_fs(oldfs);
 769         }
 770
 771         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 772
 773         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 774                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 775
 776         usb_ep_free_request(io_data->ep, io_data->req);
 777
 778         if (io_data->read)
 779                 kfree(io_data->to_free);
 780         kfree(io_data->buf);
 781         kfree(io_data);
 782 }
 783
 784 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 785                                          struct usb_request *req)
 786 {
 787         struct ffs_io_data *io_data = req->context;
 788         struct ffs_data *ffs = io_data->ffs;
 789
 790         ENTER();
 791
 792         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 793         queue_work(ffs->io_completion_wq, &io_data->work);
 794 }
 795
 796 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 797 {
 798         /*
 799          * See comment in struct ffs_epfile for full read_buffer pointer
 800          * synchronisation story.
 801          */
 802         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 803         if (buf && buf != READ_BUFFER_DROP)
 804                 kfree(buf);
 805 }
 806
 807 /* Assumes epfile->mutex is held. */
 808 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 809                                           struct iov_iter *iter)
 810 {
 811         /*
 812          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 813          * the buffer while we are using it.  See comment in struct ffs_epfile
 814          * for full read_buffer pointer synchronisation story.
 815          */
 816         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 817         ssize_t ret;
 818         if (!buf || buf == READ_BUFFER_DROP)
 819                 return 0;
 820
 821         ret = copy_to_iter(buf->data, buf->length, iter);
 822         if (buf->length == ret) {
 823                 kfree(buf);
 824                 return ret;
 825         }
 826
 827         if (unlikely(iov_iter_count(iter))) {
 828                 ret = -EFAULT;
 829         } else {
 830                 buf->length -= ret;
 831                 buf->data += ret;
 832         }
 833
 834         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 835                 kfree(buf);
 836
 837         return ret;
 838 }
 839
 840 /* Assumes epfile->mutex is held. */
 841 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 842                                       void *data, int data_len,
 843                                       struct iov_iter *iter)
 844 {
 845         struct ffs_buffer *buf;
 846
 847         ssize_t ret = copy_to_iter(data, data_len, iter);
 848         if (likely(data_len == ret))
 849                 return ret;
 850
 851         if (unlikely(iov_iter_count(iter)))
 852                 return -EFAULT;
 853
 854         /* See ffs_copy_to_iter for more context. */
 855         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 856                 data_len, ret);
 857
 858         data_len -= ret;
 859         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 860         if (!buf)
 861                 return -ENOMEM;
 862         buf->length = data_len;
 863         buf->data = buf->storage;
 864         memcpy(buf->storage, data + ret, data_len);
 865
 866         /*
 867          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 868          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 869          * in struct ffs_epfile for full read_buffer pointer synchronisation
 870          * story.
 871          */
 872         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 873                 kfree(buf);
 874
 875         return ret;
 876 }
 877
 878 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 879 {
 880         struct ffs_epfile *epfile = file->private_data;
 881         struct usb_request *req;
 882         struct ffs_ep *ep;
 883         char *data = NULL;
 884         ssize_t ret, data_len = -EINVAL;
 885         int halt;
 886
 887         /* Are we still active? */
 888         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 889                 return -ENODEV;
 890
 891         /* Wait for endpoint to be enabled */
 892         ep = epfile->ep;
 893         if (!ep) {
 894                 if (file->f_flags & O_NONBLOCK)
 895                         return -EAGAIN;
 896
 897                 ret = wait_event_interruptible(
 898                                 epfile->ffs->wait, (ep = epfile->ep));
 899                 if (ret)
 900                         return -EINTR;
 901         }
 902
 903         /* Do we halt? */
 904         halt = (!io_data->read == !epfile->in);
 905         if (halt && epfile->isoc)
 906                 return -EINVAL;
 907
 908         /* We will be using request and read_buffer */
 909         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 910         if (unlikely(ret))
 911                 goto error;
 912
 913         /* Allocate & copy */
 914         if (!halt) {
 915                 struct usb_gadget *gadget;
 916
 917                 /*
 918                  * Do we have buffered data from previous partial read?  Check
 919                  * that for synchronous case only because we do not have
 920                  * facility to ‘wake up’ a pending asynchronous read and push
 921                  * buffered data to it which we would need to make things behave
 922                  * consistently.
 923                  */
 924                 if (!io_data->aio && io_data->read) {
 925                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 926                         if (ret)
 927                                 goto error_mutex;
 928                 }
 929
 930                 /*
 931                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 932                  * before the waiting completes, so do not assign to 'gadget'
 933                  * earlier
 934                  */
 935                 gadget = epfile->ffs->gadget;
 936
 937                 spin_lock_irq(&epfile->ffs->eps_lock);
 938                 /* In the meantime, endpoint got disabled or changed. */
 939                 if (epfile->ep != ep) {
 940                         ret = -ESHUTDOWN;
 941                         goto error_lock;
 942                 }
 943                 data_len = iov_iter_count(&io_data->data);
 944                 /*
 945                  * Controller may require buffer size to be aligned to
 946                  * maxpacketsize of an out endpoint.
 947                  */
 948                 if (io_data->read)
 949                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
 950                 spin_unlock_irq(&epfile->ffs->eps_lock);
 951
 952                 data = kmalloc(data_len, GFP_KERNEL);
 953                 if (unlikely(!data)) {
 954                         ret = -ENOMEM;
 955                         goto error_mutex;
 956                 }
 957                 if (!io_data->read &&
 958                     !copy_from_iter_full(data, data_len, &io_data->data)) {
 959                         ret = -EFAULT;
 960                         goto error_mutex;
 961                 }
 962         }
 963
 964         spin_lock_irq(&epfile->ffs->eps_lock);
 965
 966         if (epfile->ep != ep) {
 967                 /* In the meantime, endpoint got disabled or changed. */
 968                 ret = -ESHUTDOWN;
 969         } else if (halt) {
 970                 ret = usb_ep_set_halt(ep->ep);
 971                 if (!ret)
 972                         ret = -EBADMSG;
 973         } else if (unlikely(data_len == -EINVAL)) {
 974                 /*
 975                  * Sanity Check: even though data_len can't be used
 976                  * uninitialized at the time I write this comment, some
 977                  * compilers complain about this situation.
 978                  * In order to keep the code clean from warnings, data_len is
 979                  * being initialized to -EINVAL during its declaration, which
 980                  * means we can't rely on compiler anymore to warn no future
 981                  * changes won't result in data_len being used uninitialized.
 982                  * For such reason, we're adding this redundant sanity check
 983                  * here.
 984                  */
 985                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
 986                 ret = -EINVAL;
 987         } else if (!io_data->aio) {
 988                 DECLARE_COMPLETION_ONSTACK(done);
 989                 bool interrupted = false;
 990
 991                 req = ep->req;
 992                 req->buf      = data;
 993                 req->length   = data_len;
 994
 995                 req->context  = &done;
 996                 req->complete = ffs_epfile_io_complete;
 997
 998                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 999                 if (unlikely(ret < 0))
1000                         goto error_lock;
1001
1002                 spin_unlock_irq(&epfile->ffs->eps_lock);
1003
1004                 if (unlikely(wait_for_completion_interruptible(&done))) {
1005                         /*
1006                          * To avoid race condition with ffs_epfile_io_complete,
1007                          * dequeue the request first then check
1008                          * status. usb_ep_dequeue API should guarantee no race
1009                          * condition with req->complete callback.
1010                          */
1011                         usb_ep_dequeue(ep->ep, req);
1012                         interrupted = ep->status < 0;
1013                 }
1014
1015                 if (interrupted)
1016                         ret = -EINTR;
1017                 else if (io_data->read && ep->status > 0)
1018                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1019                                                      &io_data->data);
1020                 else
1021                         ret = ep->status;
1022                 goto error_mutex;
1023         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1024                 ret = -ENOMEM;
1025         } else {
1026                 req->buf      = data;
1027                 req->length   = data_len;
1028
1029                 io_data->buf = data;
1030                 io_data->ep = ep->ep;
1031                 io_data->req = req;
1032                 io_data->ffs = epfile->ffs;
1033
1034                 req->context  = io_data;
1035                 req->complete = ffs_epfile_async_io_complete;
1036
1037                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1038                 if (unlikely(ret)) {
1039                         usb_ep_free_request(ep->ep, req);
1040                         goto error_lock;
1041                 }
1042
1043                 ret = -EIOCBQUEUED;
1044                 /*
1045                  * Do not kfree the buffer in this function.  It will be freed
1046                  * by ffs_user_copy_worker.
1047                  */
1048                 data = NULL;
1049         }
1050
1051 error_lock:
1052         spin_unlock_irq(&epfile->ffs->eps_lock);
1053 error_mutex:
1054         mutex_unlock(&epfile->mutex);
1055 error:
1056         kfree(data);
1057         return ret;
1058 }
1059
1060 static int
1061 ffs_epfile_open(struct inode *inode, struct file *file)
1062 {
1063         struct ffs_epfile *epfile = inode->i_private;
1064
1065         ENTER();
1066
1067         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1068                 return -ENODEV;
1069
1070         file->private_data = epfile;
1071         ffs_data_opened(epfile->ffs);
1072
1073         return 0;
1074 }
1075
1076 static void ffs_aio_cancel_worker(struct work_struct *work)
1077 {
1078         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
1079                                                    cancellation_work);
1080
1081         ENTER();
1082
1083         usb_ep_dequeue(io_data->ep, io_data->req);
1084 }
1085
1086 static int ffs_aio_cancel(struct kiocb *kiocb)
1087 {
1088         struct ffs_io_data *io_data = kiocb->private;
1089         struct ffs_data *ffs = io_data->ffs;
1090         int value;
1091
1092         ENTER();
1093
1094         if (likely(io_data && io_data->ep && io_data->req)) {
1095                 INIT_WORK(&io_data->cancellation_work, ffs_aio_cancel_worker);
1096                 queue_work(ffs->io_completion_wq, &io_data->cancellation_work);
1097                 value = -EINPROGRESS;
1098         } else {
1099                 value = -EINVAL;
1100         }
1101
1102         return value;
1103 }
1104
1105 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1106 {
1107         struct ffs_io_data io_data, *p = &io_data;
1108         ssize_t res;
1109
1110         ENTER();
1111
1112         if (!is_sync_kiocb(kiocb)) {
1113                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1114                 if (unlikely(!p))
1115                         return -ENOMEM;
1116                 p->aio = true;
1117         } else {
1118                 p->aio = false;
1119         }
1120
1121         p->read = false;
1122         p->kiocb = kiocb;
1123         p->data = *from;
1124         p->mm = current->mm;
1125
1126         kiocb->private = p;
1127
1128         if (p->aio)
1129                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1130
1131         res = ffs_epfile_io(kiocb->ki_filp, p);
1132         if (res == -EIOCBQUEUED)
1133                 return res;
1134         if (p->aio)
1135                 kfree(p);
1136         else
1137                 *from = p->data;
1138         return res;
1139 }
1140
1141 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1142 {
1143         struct ffs_io_data io_data, *p = &io_data;
1144         ssize_t res;
1145
1146         ENTER();
1147
1148         if (!is_sync_kiocb(kiocb)) {
1149                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1150                 if (unlikely(!p))
1151                         return -ENOMEM;
1152                 p->aio = true;
1153         } else {
1154                 p->aio = false;
1155         }
1156
1157         p->read = true;
1158         p->kiocb = kiocb;
1159         if (p->aio) {
1160                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1161                 if (!p->to_free) {
1162                         kfree(p);
1163                         return -ENOMEM;
1164                 }
1165         } else {
1166                 p->data = *to;
1167                 p->to_free = NULL;
1168         }
1169         p->mm = current->mm;
1170
1171         kiocb->private = p;
1172
1173         if (p->aio)
1174                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1175
1176         res = ffs_epfile_io(kiocb->ki_filp, p);
1177         if (res == -EIOCBQUEUED)
1178                 return res;
1179
1180         if (p->aio) {
1181                 kfree(p->to_free);
1182                 kfree(p);
1183         } else {
1184                 *to = p->data;
1185         }
1186         return res;
1187 }
1188
1189 static int
1190 ffs_epfile_release(struct inode *inode, struct file *file)
1191 {
1192         struct ffs_epfile *epfile = inode->i_private;
1193
1194         ENTER();
1195
1196         __ffs_epfile_read_buffer_free(epfile);
1197         ffs_data_closed(epfile->ffs);
1198
1199         return 0;
1200 }
1201
1202 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1203                              unsigned long value)
1204 {
1205         struct ffs_epfile *epfile = file->private_data;
1206         struct ffs_ep *ep;
1207         int ret;
1208
1209         ENTER();
1210
1211         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1212                 return -ENODEV;
1213
1214         /* Wait for endpoint to be enabled */
1215         ep = epfile->ep;
1216         if (!ep) {
1217                 if (file->f_flags & O_NONBLOCK)
1218                         return -EAGAIN;
1219
1220                 ret = wait_event_interruptible(
1221                                 epfile->ffs->wait, (ep = epfile->ep));
1222                 if (ret)
1223                         return -EINTR;
1224         }
1225
1226         spin_lock_irq(&epfile->ffs->eps_lock);
1227
1228         /* In the meantime, endpoint got disabled or changed. */
1229         if (epfile->ep != ep) {
1230                 spin_unlock_irq(&epfile->ffs->eps_lock);
1231                 return -ESHUTDOWN;
1232         }
1233
1234         switch (code) {
1235         case FUNCTIONFS_FIFO_STATUS:
1236                 ret = usb_ep_fifo_status(epfile->ep->ep);
1237                 break;
1238         case FUNCTIONFS_FIFO_FLUSH:
1239                 usb_ep_fifo_flush(epfile->ep->ep);
1240                 ret = 0;
1241                 break;
1242         case FUNCTIONFS_CLEAR_HALT:
1243                 ret = usb_ep_clear_halt(epfile->ep->ep);
1244                 break;
1245         case FUNCTIONFS_ENDPOINT_REVMAP:
1246                 ret = epfile->ep->num;
1247                 break;
1248         case FUNCTIONFS_ENDPOINT_DESC:
1249         {
1250                 int desc_idx;
1251                 struct usb_endpoint_descriptor *desc;
1252
1253                 switch (epfile->ffs->gadget->speed) {
1254                 case USB_SPEED_SUPER:
1255                         desc_idx = 2;
1256                         break;
1257                 case USB_SPEED_HIGH:
1258                         desc_idx = 1;
1259                         break;
1260                 default:
1261                         desc_idx = 0;
1262                 }
1263                 desc = epfile->ep->descs[desc_idx];
1264
1265                 spin_unlock_irq(&epfile->ffs->eps_lock);
1266                 ret = copy_to_user((void __user *)value, desc, desc->bLength);
1267                 if (ret)
1268                         ret = -EFAULT;
1269                 return ret;
1270         }
1271         default:
1272                 ret = -ENOTTY;
1273         }
1274         spin_unlock_irq(&epfile->ffs->eps_lock);
1275
1276         return ret;
1277 }
1278
1279 #ifdef CONFIG_COMPAT
1280 static long ffs_epfile_compat_ioctl(struct file *file, unsigned code,
1281                 unsigned long value)
1282 {
1283         return ffs_epfile_ioctl(file, code, value);
1284 }
1285 #endif
1286
1287 static const struct file_operations ffs_epfile_operations = {
1288         .llseek =       no_llseek,
1289
1290         .open =         ffs_epfile_open,
1291         .write_iter =   ffs_epfile_write_iter,
1292         .read_iter =    ffs_epfile_read_iter,
1293         .release =      ffs_epfile_release,
1294         .unlocked_ioctl =       ffs_epfile_ioctl,
1295 #ifdef CONFIG_COMPAT
1296         .compat_ioctl = ffs_epfile_compat_ioctl,
1297 #endif
1298 };
1299
1300
1301 /* File system and super block operations ***********************************/
1302
1303 /*
1304  * Mounting the file system creates a controller file, used first for
1305  * function configuration then later for event monitoring.
1306  */
1307
1308 static struct inode *__must_check
1309 ffs_sb_make_inode(struct super_block *sb, void *data,
1310                   const struct file_operations *fops,
1311                   const struct inode_operations *iops,
1312                   struct ffs_file_perms *perms)
1313 {
1314         struct inode *inode;
1315
1316         ENTER();
1317
1318         inode = new_inode(sb);
1319
1320         if (likely(inode)) {
1321                 struct timespec64 ts = current_time(inode);
1322
1323                 inode->i_ino     = get_next_ino();
1324                 inode->i_mode    = perms->mode;
1325                 inode->i_uid     = perms->uid;
1326                 inode->i_gid     = perms->gid;
1327                 inode->i_atime   = ts;
1328                 inode->i_mtime   = ts;
1329                 inode->i_ctime   = ts;
1330                 inode->i_private = data;
1331                 if (fops)
1332                         inode->i_fop = fops;
1333                 if (iops)
1334                         inode->i_op  = iops;
1335         }
1336
1337         return inode;
1338 }
1339
1340 /* Create "regular" file */
1341 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1342                                         const char *name, void *data,
1343                                         const struct file_operations *fops)
1344 {
1345         struct ffs_data *ffs = sb->s_fs_info;
1346         struct dentry   *dentry;
1347         struct inode    *inode;
1348
1349         ENTER();
1350
1351         dentry = d_alloc_name(sb->s_root, name);
1352         if (unlikely(!dentry))
1353                 return NULL;
1354
1355         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1356         if (unlikely(!inode)) {
1357                 dput(dentry);
1358                 return NULL;
1359         }
1360
1361         d_add(dentry, inode);
1362         return dentry;
1363 }
1364
1365 /* Super block */
1366 static const struct super_operations ffs_sb_operations = {
1367         .statfs =       simple_statfs,
1368         .drop_inode =   generic_delete_inode,
1369 };
1370
1371 struct ffs_sb_fill_data {
1372         struct ffs_file_perms perms;
1373         umode_t root_mode;
1374         const char *dev_name;
1375         bool no_disconnect;
1376         struct ffs_data *ffs_data;
1377 };
1378
1379 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1380 {
1381         struct ffs_sb_fill_data *data = _data;
1382         struct inode    *inode;
1383         struct ffs_data *ffs = data->ffs_data;
1384
1385         ENTER();
1386
1387         ffs->sb              = sb;
1388         data->ffs_data       = NULL;
1389         sb->s_fs_info        = ffs;
1390         sb->s_blocksize      = PAGE_SIZE;
1391         sb->s_blocksize_bits = PAGE_SHIFT;
1392         sb->s_magic          = FUNCTIONFS_MAGIC;
1393         sb->s_op             = &ffs_sb_operations;
1394         sb->s_time_gran      = 1;
1395
1396         /* Root inode */
1397         data->perms.mode = data->root_mode;
1398         inode = ffs_sb_make_inode(sb, NULL,
1399                                   &simple_dir_operations,
1400                                   &simple_dir_inode_operations,
1401                                   &data->perms);
1402         sb->s_root = d_make_root(inode);
1403         if (unlikely(!sb->s_root))
1404                 return -ENOMEM;
1405
1406         /* EP0 file */
1407         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1408                                          &ffs_ep0_operations)))
1409                 return -ENOMEM;
1410
1411         return 0;
1412 }
1413
1414 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1415 {
1416         ENTER();
1417
1418         if (!opts || !*opts)
1419                 return 0;
1420
1421         for (;;) {
1422                 unsigned long value;
1423                 char *eq, *comma;
1424
1425                 /* Option limit */
1426                 comma = strchr(opts, ',');
1427                 if (comma)
1428                         *comma = 0;
1429
1430                 /* Value limit */
1431                 eq = strchr(opts, '=');
1432                 if (unlikely(!eq)) {
1433                         pr_err("'=' missing in %s\n", opts);
1434                         return -EINVAL;
1435                 }
1436                 *eq = 0;
1437
1438                 /* Parse value */
1439                 if (kstrtoul(eq + 1, 0, &value)) {
1440                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1441                         return -EINVAL;
1442                 }
1443
1444                 /* Interpret option */
1445                 switch (eq - opts) {
1446                 case 13:
1447                         if (!memcmp(opts, "no_disconnect", 13))
1448                                 data->no_disconnect = !!value;
1449                         else
1450                                 goto invalid;
1451                         break;
1452                 case 5:
1453                         if (!memcmp(opts, "rmode", 5))
1454                                 data->root_mode  = (value & 0555) | S_IFDIR;
1455                         else if (!memcmp(opts, "fmode", 5))
1456                                 data->perms.mode = (value & 0666) | S_IFREG;
1457                         else
1458                                 goto invalid;
1459                         break;
1460
1461                 case 4:
1462                         if (!memcmp(opts, "mode", 4)) {
1463                                 data->root_mode  = (value & 0555) | S_IFDIR;
1464                                 data->perms.mode = (value & 0666) | S_IFREG;
1465                         } else {
1466                                 goto invalid;
1467                         }
1468                         break;
1469
1470                 case 3:
1471                         if (!memcmp(opts, "uid", 3)) {
1472                                 data->perms.uid = make_kuid(current_user_ns(), value);
1473                                 if (!uid_valid(data->perms.uid)) {
1474                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1475                                         return -EINVAL;
1476                                 }
1477                         } else if (!memcmp(opts, "gid", 3)) {
1478                                 data->perms.gid = make_kgid(current_user_ns(), value);
1479                                 if (!gid_valid(data->perms.gid)) {
1480                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1481                                         return -EINVAL;
1482                                 }
1483                         } else {
1484                                 goto invalid;
1485                         }
1486                         break;
1487
1488                 default:
1489 invalid:
1490                         pr_err("%s: invalid option\n", opts);
1491                         return -EINVAL;
1492                 }
1493
1494                 /* Next iteration */
1495                 if (!comma)
1496                         break;
1497                 opts = comma + 1;
1498         }
1499
1500         return 0;
1501 }
1502
1503 /* "mount -t functionfs dev_name /dev/function" ends up here */
1504
1505 static struct dentry *
1506 ffs_fs_mount(struct file_system_type *t, int flags,
1507               const char *dev_name, void *opts)
1508 {
1509         struct ffs_sb_fill_data data = {
1510                 .perms = {
1511                         .mode = S_IFREG | 0600,
1512                         .uid = GLOBAL_ROOT_UID,
1513                         .gid = GLOBAL_ROOT_GID,
1514                 },
1515                 .root_mode = S_IFDIR | 0500,
1516                 .no_disconnect = false,
1517         };
1518         struct dentry *rv;
1519         int ret;
1520         void *ffs_dev;
1521         struct ffs_data *ffs;
1522
1523         ENTER();
1524
1525         ret = ffs_fs_parse_opts(&data, opts);
1526         if (unlikely(ret < 0))
1527                 return ERR_PTR(ret);
1528
1529         ffs = ffs_data_new(dev_name);
1530         if (unlikely(!ffs))
1531                 return ERR_PTR(-ENOMEM);
1532         ffs->file_perms = data.perms;
1533         ffs->no_disconnect = data.no_disconnect;
1534
1535         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1536         if (unlikely(!ffs->dev_name)) {
1537                 ffs_data_put(ffs);
1538                 return ERR_PTR(-ENOMEM);
1539         }
1540
1541         ffs_dev = ffs_acquire_dev(dev_name);
1542         if (IS_ERR(ffs_dev)) {
1543                 ffs_data_put(ffs);
1544                 return ERR_CAST(ffs_dev);
1545         }
1546         ffs->private_data = ffs_dev;
1547         data.ffs_data = ffs;
1548
1549         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1550         if (IS_ERR(rv) && data.ffs_data) {
1551                 ffs_release_dev(data.ffs_data);
1552                 ffs_data_put(data.ffs_data);
1553         }
1554         return rv;
1555 }
1556
1557 static void
1558 ffs_fs_kill_sb(struct super_block *sb)
1559 {
1560         ENTER();
1561
1562         kill_litter_super(sb);
1563         if (sb->s_fs_info) {
1564                 ffs_release_dev(sb->s_fs_info);
1565                 ffs_data_closed(sb->s_fs_info);
1566         }
1567 }
1568
1569 static struct file_system_type ffs_fs_type = {
1570         .owner          = THIS_MODULE,
1571         .name           = "functionfs",
1572         .mount          = ffs_fs_mount,
1573         .kill_sb        = ffs_fs_kill_sb,
1574 };
1575 MODULE_ALIAS_FS("functionfs");
1576
1577
1578 /* Driver's main init/cleanup functions *************************************/
1579
1580 static int functionfs_init(void)
1581 {
1582         int ret;
1583
1584         ENTER();
1585
1586         ret = register_filesystem(&ffs_fs_type);
1587         if (likely(!ret))
1588                 pr_info("file system registered\n");
1589         else
1590                 pr_err("failed registering file system (%d)\n", ret);
1591
1592         return ret;
1593 }
1594
1595 static void functionfs_cleanup(void)
1596 {
1597         ENTER();
1598
1599         pr_info("unloading\n");
1600         unregister_filesystem(&ffs_fs_type);
1601 }
1602
1603
1604 /* ffs_data and ffs_function construction and destruction code **************/
1605
1606 static void ffs_data_clear(struct ffs_data *ffs);
1607 static void ffs_data_reset(struct ffs_data *ffs);
1608
1609 static void ffs_data_get(struct ffs_data *ffs)
1610 {
1611         ENTER();
1612
1613         refcount_inc(&ffs->ref);
1614 }
1615
1616 static void ffs_data_opened(struct ffs_data *ffs)
1617 {
1618         ENTER();
1619
1620         refcount_inc(&ffs->ref);
1621         if (atomic_add_return(1, &ffs->opened) == 1 &&
1622                         ffs->state == FFS_DEACTIVATED) {
1623                 ffs->state = FFS_CLOSING;
1624                 ffs_data_reset(ffs);
1625         }
1626 }
1627
1628 static void ffs_data_put(struct ffs_data *ffs)
1629 {
1630         ENTER();
1631
1632         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1633                 pr_info("%s(): freeing\n", __func__);
1634                 ffs_data_clear(ffs);
1635                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1636                        waitqueue_active(&ffs->ep0req_completion.wait) ||
1637                        waitqueue_active(&ffs->wait));
1638                 destroy_workqueue(ffs->io_completion_wq);
1639                 kfree(ffs->dev_name);
1640                 kfree(ffs);
1641         }
1642 }
1643
1644 static void ffs_data_closed(struct ffs_data *ffs)
1645 {
1646         ENTER();
1647
1648         if (atomic_dec_and_test(&ffs->opened)) {
1649                 if (ffs->no_disconnect) {
1650                         ffs->state = FFS_DEACTIVATED;
1651                         if (ffs->epfiles) {
1652                                 ffs_epfiles_destroy(ffs->epfiles,
1653                                                    ffs->eps_count);
1654                                 ffs->epfiles = NULL;
1655                         }
1656                         if (ffs->setup_state == FFS_SETUP_PENDING)
1657                                 __ffs_ep0_stall(ffs);
1658                 } else {
1659                         ffs->state = FFS_CLOSING;
1660                         ffs_data_reset(ffs);
1661                 }
1662         }
1663         if (atomic_read(&ffs->opened) < 0) {
1664                 ffs->state = FFS_CLOSING;
1665                 ffs_data_reset(ffs);
1666         }
1667
1668         ffs_data_put(ffs);
1669 }
1670
1671 static struct ffs_data *ffs_data_new(const char *dev_name)
1672 {
1673         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1674         if (unlikely(!ffs))
1675                 return NULL;
1676
1677         ENTER();
1678
1679         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1680         if (!ffs->io_completion_wq) {
1681                 kfree(ffs);
1682                 return NULL;
1683         }
1684
1685         refcount_set(&ffs->ref, 1);
1686         atomic_set(&ffs->opened, 0);
1687         ffs->state = FFS_READ_DESCRIPTORS;
1688         mutex_init(&ffs->mutex);
1689         spin_lock_init(&ffs->eps_lock);
1690         init_waitqueue_head(&ffs->ev.waitq);
1691         init_waitqueue_head(&ffs->wait);
1692         init_completion(&ffs->ep0req_completion);
1693
1694         /* XXX REVISIT need to update it in some places, or do we? */
1695         ffs->ev.can_stall = 1;
1696
1697         return ffs;
1698 }
1699
1700 static void ffs_data_clear(struct ffs_data *ffs)
1701 {
1702         ENTER();
1703
1704         ffs_closed(ffs);
1705
1706         BUG_ON(ffs->gadget);
1707
1708         if (ffs->epfiles)
1709                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1710
1711         if (ffs->ffs_eventfd)
1712                 eventfd_ctx_put(ffs->ffs_eventfd);
1713
1714         kfree(ffs->raw_descs_data);
1715         kfree(ffs->raw_strings);
1716         kfree(ffs->stringtabs);
1717 }
1718
1719 static void ffs_data_reset(struct ffs_data *ffs)
1720 {
1721         ENTER();
1722
1723         ffs_data_clear(ffs);
1724
1725         ffs->epfiles = NULL;
1726         ffs->raw_descs_data = NULL;
1727         ffs->raw_descs = NULL;
1728         ffs->raw_strings = NULL;
1729         ffs->stringtabs = NULL;
1730
1731         ffs->raw_descs_length = 0;
1732         ffs->fs_descs_count = 0;
1733         ffs->hs_descs_count = 0;
1734         ffs->ss_descs_count = 0;
1735
1736         ffs->strings_count = 0;
1737         ffs->interfaces_count = 0;
1738         ffs->eps_count = 0;
1739
1740         ffs->ev.count = 0;
1741
1742         ffs->state = FFS_READ_DESCRIPTORS;
1743         ffs->setup_state = FFS_NO_SETUP;
1744         ffs->flags = 0;
1745 }
1746
1747
1748 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1749 {
1750         struct usb_gadget_strings **lang;
1751         int first_id;
1752
1753         ENTER();
1754
1755         if (WARN_ON(ffs->state != FFS_ACTIVE
1756                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1757                 return -EBADFD;
1758
1759         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1760         if (unlikely(first_id < 0))
1761                 return first_id;
1762
1763         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1764         if (unlikely(!ffs->ep0req))
1765                 return -ENOMEM;
1766         ffs->ep0req->complete = ffs_ep0_complete;
1767         ffs->ep0req->context = ffs;
1768
1769         lang = ffs->stringtabs;
1770         if (lang) {
1771                 for (; *lang; ++lang) {
1772                         struct usb_string *str = (*lang)->strings;
1773                         int id = first_id;
1774                         for (; str->s; ++id, ++str)
1775                                 str->id = id;
1776                 }
1777         }
1778
1779         ffs->gadget = cdev->gadget;
1780         ffs_data_get(ffs);
1781         return 0;
1782 }
1783
1784 static void functionfs_unbind(struct ffs_data *ffs)
1785 {
1786         ENTER();
1787
1788         if (!WARN_ON(!ffs->gadget)) {
1789                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1790                 ffs->ep0req = NULL;
1791                 ffs->gadget = NULL;
1792                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1793                 ffs_data_put(ffs);
1794         }
1795 }
1796
1797 static int ffs_epfiles_create(struct ffs_data *ffs)
1798 {
1799         struct ffs_epfile *epfile, *epfiles;
1800         unsigned i, count;
1801
1802         ENTER();
1803
1804         count = ffs->eps_count;
1805         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1806         if (!epfiles)
1807                 return -ENOMEM;
1808
1809         epfile = epfiles;
1810         for (i = 1; i <= count; ++i, ++epfile) {
1811                 epfile->ffs = ffs;
1812                 mutex_init(&epfile->mutex);
1813                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1814                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1815                 else
1816                         sprintf(epfile->name, "ep%u", i);
1817                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1818                                                  epfile,
1819                                                  &ffs_epfile_operations);
1820                 if (unlikely(!epfile->dentry)) {
1821                         ffs_epfiles_destroy(epfiles, i - 1);
1822                         return -ENOMEM;
1823                 }
1824         }
1825
1826         ffs->epfiles = epfiles;
1827         return 0;
1828 }
1829
1830 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1831 {
1832         struct ffs_epfile *epfile = epfiles;
1833
1834         ENTER();
1835
1836         for (; count; --count, ++epfile) {
1837                 BUG_ON(mutex_is_locked(&epfile->mutex));
1838                 if (epfile->dentry) {
1839                         d_delete(epfile->dentry);
1840                         dput(epfile->dentry);
1841                         epfile->dentry = NULL;
1842                 }
1843         }
1844
1845         kfree(epfiles);
1846 }
1847
1848 static void ffs_func_eps_disable(struct ffs_function *func)
1849 {
1850         struct ffs_ep *ep         = func->eps;
1851         struct ffs_epfile *epfile = func->ffs->epfiles;
1852         unsigned count            = func->ffs->eps_count;
1853         unsigned long flags;
1854
1855         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1856         while (count--) {
1857                 /* pending requests get nuked */
1858                 if (likely(ep->ep))
1859                         usb_ep_disable(ep->ep);
1860                 ++ep;
1861
1862                 if (epfile) {
1863                         epfile->ep = NULL;
1864                         __ffs_epfile_read_buffer_free(epfile);
1865                         ++epfile;
1866                 }
1867         }
1868         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1869 }
1870
1871 static int ffs_func_eps_enable(struct ffs_function *func)
1872 {
1873         struct ffs_data *ffs      = func->ffs;
1874         struct ffs_ep *ep         = func->eps;
1875         struct ffs_epfile *epfile = ffs->epfiles;
1876         unsigned count            = ffs->eps_count;
1877         unsigned long flags;
1878         int ret = 0;
1879
1880         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1881         while(count--) {
1882                 ep->ep->driver_data = ep;
1883
1884                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1885                 if (ret) {
1886                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1887                                         __func__, ep->ep->name, ret);
1888                         break;
1889                 }
1890
1891                 ret = usb_ep_enable(ep->ep);
1892                 if (likely(!ret)) {
1893                         epfile->ep = ep;
1894                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1895                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1896                 } else {
1897                         break;
1898                 }
1899
1900                 ++ep;
1901                 ++epfile;
1902         }
1903
1904         wake_up_interruptible(&ffs->wait);
1905         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1906
1907         return ret;
1908 }
1909
1910
1911 /* Parsing and building descriptors and strings *****************************/
1912
1913 /*
1914  * This validates if data pointed by data is a valid USB descriptor as
1915  * well as record how many interfaces, endpoints and strings are
1916  * required by given configuration.  Returns address after the
1917  * descriptor or NULL if data is invalid.
1918  */
1919
1920 enum ffs_entity_type {
1921         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1922 };
1923
1924 enum ffs_os_desc_type {
1925         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1926 };
1927
1928 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1929                                    u8 *valuep,
1930                                    struct usb_descriptor_header *desc,
1931                                    void *priv);
1932
1933 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1934                                     struct usb_os_desc_header *h, void *data,
1935                                     unsigned len, void *priv);
1936
1937 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1938                                            ffs_entity_callback entity,
1939                                            void *priv)
1940 {
1941         struct usb_descriptor_header *_ds = (void *)data;
1942         u8 length;
1943         int ret;
1944
1945         ENTER();
1946
1947         /* At least two bytes are required: length and type */
1948         if (len < 2) {
1949                 pr_vdebug("descriptor too short\n");
1950                 return -EINVAL;
1951         }
1952
1953         /* If we have at least as many bytes as the descriptor takes? */
1954         length = _ds->bLength;
1955         if (len < length) {
1956                 pr_vdebug("descriptor longer then available data\n");
1957                 return -EINVAL;
1958         }
1959
1960 #define __entity_check_INTERFACE(val)  1
1961 #define __entity_check_STRING(val)     (val)
1962 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1963 #define __entity(type, val) do {                                        \
1964                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1965                 if (unlikely(!__entity_check_ ##type(val))) {           \
1966                         pr_vdebug("invalid entity's value\n");          \
1967                         return -EINVAL;                                 \
1968                 }                                                       \
1969                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1970                 if (unlikely(ret < 0)) {                                \
1971                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1972                                  (val), ret);                           \
1973                         return ret;                                     \
1974                 }                                                       \
1975         } while (0)
1976
1977         /* Parse descriptor depending on type. */
1978         switch (_ds->bDescriptorType) {
1979         case USB_DT_DEVICE:
1980         case USB_DT_CONFIG:
1981         case USB_DT_STRING:
1982         case USB_DT_DEVICE_QUALIFIER:
1983                 /* function can't have any of those */
1984                 pr_vdebug("descriptor reserved for gadget: %d\n",
1985                       _ds->bDescriptorType);
1986                 return -EINVAL;
1987
1988         case USB_DT_INTERFACE: {
1989                 struct usb_interface_descriptor *ds = (void *)_ds;
1990                 pr_vdebug("interface descriptor\n");
1991                 if (length != sizeof *ds)
1992                         goto inv_length;
1993
1994                 __entity(INTERFACE, ds->bInterfaceNumber);
1995                 if (ds->iInterface)
1996                         __entity(STRING, ds->iInterface);
1997         }
1998                 break;
1999
2000         case USB_DT_ENDPOINT: {
2001                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2002                 pr_vdebug("endpoint descriptor\n");
2003                 if (length != USB_DT_ENDPOINT_SIZE &&
2004                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2005                         goto inv_length;
2006                 __entity(ENDPOINT, ds->bEndpointAddress);
2007         }
2008                 break;
2009
2010         case HID_DT_HID:
2011                 pr_vdebug("hid descriptor\n");
2012                 if (length != sizeof(struct hid_descriptor))
2013                         goto inv_length;
2014                 break;
2015
2016         case USB_DT_OTG:
2017                 if (length != sizeof(struct usb_otg_descriptor))
2018                         goto inv_length;
2019                 break;
2020
2021         case USB_DT_INTERFACE_ASSOCIATION: {
2022                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2023                 pr_vdebug("interface association descriptor\n");
2024                 if (length != sizeof *ds)
2025                         goto inv_length;
2026                 if (ds->iFunction)
2027                         __entity(STRING, ds->iFunction);
2028         }
2029                 break;
2030
2031         case USB_DT_SS_ENDPOINT_COMP:
2032                 pr_vdebug("EP SS companion descriptor\n");
2033                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2034                         goto inv_length;
2035                 break;
2036
2037         case USB_DT_OTHER_SPEED_CONFIG:
2038         case USB_DT_INTERFACE_POWER:
2039         case USB_DT_DEBUG:
2040         case USB_DT_SECURITY:
2041         case USB_DT_CS_RADIO_CONTROL:
2042                 /* TODO */
2043                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2044                 return -EINVAL;
2045
2046         default:
2047                 /* We should never be here */
2048                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2049                 return -EINVAL;
2050
2051 inv_length:
2052                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2053                           _ds->bLength, _ds->bDescriptorType);
2054                 return -EINVAL;
2055         }
2056
2057 #undef __entity
2058 #undef __entity_check_DESCRIPTOR
2059 #undef __entity_check_INTERFACE
2060 #undef __entity_check_STRING
2061 #undef __entity_check_ENDPOINT
2062
2063         return length;
2064 }
2065
2066 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2067                                      ffs_entity_callback entity, void *priv)
2068 {
2069         const unsigned _len = len;
2070         unsigned long num = 0;
2071
2072         ENTER();
2073
2074         for (;;) {
2075                 int ret;
2076
2077                 if (num == count)
2078                         data = NULL;
2079
2080                 /* Record "descriptor" entity */
2081                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2082                 if (unlikely(ret < 0)) {
2083                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2084                                  num, ret);
2085                         return ret;
2086                 }
2087
2088                 if (!data)
2089                         return _len - len;
2090
2091                 ret = ffs_do_single_desc(data, len, entity, priv);
2092                 if (unlikely(ret < 0)) {
2093                         pr_debug("%s returns %d\n", __func__, ret);
2094                         return ret;
2095                 }
2096
2097                 len -= ret;
2098                 data += ret;
2099                 ++num;
2100         }
2101 }
2102
2103 static int __ffs_data_do_entity(enum ffs_entity_type type,
2104                                 u8 *valuep, struct usb_descriptor_header *desc,
2105                                 void *priv)
2106 {
2107         struct ffs_desc_helper *helper = priv;
2108         struct usb_endpoint_descriptor *d;
2109
2110         ENTER();
2111
2112         switch (type) {
2113         case FFS_DESCRIPTOR:
2114                 break;
2115
2116         case FFS_INTERFACE:
2117                 /*
2118                  * Interfaces are indexed from zero so if we
2119                  * encountered interface "n" then there are at least
2120                  * "n+1" interfaces.
2121                  */
2122                 if (*valuep >= helper->interfaces_count)
2123                         helper->interfaces_count = *valuep + 1;
2124                 break;
2125
2126         case FFS_STRING:
2127                 /*
2128                  * Strings are indexed from 1 (0 is reserved
2129                  * for languages list)
2130                  */
2131                 if (*valuep > helper->ffs->strings_count)
2132                         helper->ffs->strings_count = *valuep;
2133                 break;
2134
2135         case FFS_ENDPOINT:
2136                 d = (void *)desc;
2137                 helper->eps_count++;
2138                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2139                         return -EINVAL;
2140                 /* Check if descriptors for any speed were already parsed */
2141                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2142                         helper->ffs->eps_addrmap[helper->eps_count] =
2143                                 d->bEndpointAddress;
2144                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2145                                 d->bEndpointAddress)
2146                         return -EINVAL;
2147                 break;
2148         }
2149
2150         return 0;
2151 }
2152
2153 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2154                                    struct usb_os_desc_header *desc)
2155 {
2156         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2157         u16 w_index = le16_to_cpu(desc->wIndex);
2158
2159         if (bcd_version != 1) {
2160                 pr_vdebug("unsupported os descriptors version: %d",
2161                           bcd_version);
2162                 return -EINVAL;
2163         }
2164         switch (w_index) {
2165         case 0x4:
2166                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2167                 break;
2168         case 0x5:
2169                 *next_type = FFS_OS_DESC_EXT_PROP;
2170                 break;
2171         default:
2172                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2173                 return -EINVAL;
2174         }
2175
2176         return sizeof(*desc);
2177 }
2178
2179 /*
2180  * Process all extended compatibility/extended property descriptors
2181  * of a feature descriptor
2182  */
2183 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2184                                               enum ffs_os_desc_type type,
2185                                               u16 feature_count,
2186                                               ffs_os_desc_callback entity,
2187                                               void *priv,
2188                                               struct usb_os_desc_header *h)
2189 {
2190         int ret;
2191         const unsigned _len = len;
2192
2193         ENTER();
2194
2195         /* loop over all ext compat/ext prop descriptors */
2196         while (feature_count--) {
2197                 ret = entity(type, h, data, len, priv);
2198                 if (unlikely(ret < 0)) {
2199                         pr_debug("bad OS descriptor, type: %d\n", type);
2200                         return ret;
2201                 }
2202                 data += ret;
2203                 len -= ret;
2204         }
2205         return _len - len;
2206 }
2207
2208 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2209 static int __must_check ffs_do_os_descs(unsigned count,
2210                                         char *data, unsigned len,
2211                                         ffs_os_desc_callback entity, void *priv)
2212 {
2213         const unsigned _len = len;
2214         unsigned long num = 0;
2215
2216         ENTER();
2217
2218         for (num = 0; num < count; ++num) {
2219                 int ret;
2220                 enum ffs_os_desc_type type;
2221                 u16 feature_count;
2222                 struct usb_os_desc_header *desc = (void *)data;
2223
2224                 if (len < sizeof(*desc))
2225                         return -EINVAL;
2226
2227                 /*
2228                  * Record "descriptor" entity.
2229                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2230                  * Move the data pointer to the beginning of extended
2231                  * compatibilities proper or extended properties proper
2232                  * portions of the data
2233                  */
2234                 if (le32_to_cpu(desc->dwLength) > len)
2235                         return -EINVAL;
2236
2237                 ret = __ffs_do_os_desc_header(&type, desc);
2238                 if (unlikely(ret < 0)) {
2239                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2240                                  num, ret);
2241                         return ret;
2242                 }
2243                 /*
2244                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2245                  */
2246                 feature_count = le16_to_cpu(desc->wCount);
2247                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2248                     (feature_count > 255 || desc->Reserved))
2249                                 return -EINVAL;
2250                 len -= ret;
2251                 data += ret;
2252
2253                 /*
2254                  * Process all function/property descriptors
2255                  * of this Feature Descriptor
2256                  */
2257                 ret = ffs_do_single_os_desc(data, len, type,
2258                                             feature_count, entity, priv, desc);
2259                 if (unlikely(ret < 0)) {
2260                         pr_debug("%s returns %d\n", __func__, ret);
2261                         return ret;
2262                 }
2263
2264                 len -= ret;
2265                 data += ret;
2266         }
2267         return _len - len;
2268 }
2269
2270 /**
2271  * Validate contents of the buffer from userspace related to OS descriptors.
2272  */
2273 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2274                                  struct usb_os_desc_header *h, void *data,
2275                                  unsigned len, void *priv)
2276 {
2277         struct ffs_data *ffs = priv;
2278         u8 length;
2279
2280         ENTER();
2281
2282         switch (type) {
2283         case FFS_OS_DESC_EXT_COMPAT: {
2284                 struct usb_ext_compat_desc *d = data;
2285                 int i;
2286
2287                 if (len < sizeof(*d) ||
2288                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2289                         return -EINVAL;
2290                 if (d->Reserved1 != 1) {
2291                         /*
2292                          * According to the spec, Reserved1 must be set to 1
2293                          * but older kernels incorrectly rejected non-zero
2294                          * values.  We fix it here to avoid returning EINVAL
2295                          * in response to values we used to accept.
2296                          */
2297                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2298                         d->Reserved1 = 1;
2299                 }
2300                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2301                         if (d->Reserved2[i])
2302                                 return -EINVAL;
2303
2304                 length = sizeof(struct usb_ext_compat_desc);
2305         }
2306                 break;
2307         case FFS_OS_DESC_EXT_PROP: {
2308                 struct usb_ext_prop_desc *d = data;
2309                 u32 type, pdl;
2310                 u16 pnl;
2311
2312                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2313                         return -EINVAL;
2314                 length = le32_to_cpu(d->dwSize);
2315                 if (len < length)
2316                         return -EINVAL;
2317                 type = le32_to_cpu(d->dwPropertyDataType);
2318                 if (type < USB_EXT_PROP_UNICODE ||
2319                     type > USB_EXT_PROP_UNICODE_MULTI) {
2320                         pr_vdebug("unsupported os descriptor property type: %d",
2321                                   type);
2322                         return -EINVAL;
2323                 }
2324                 pnl = le16_to_cpu(d->wPropertyNameLength);
2325                 if (length < 14 + pnl) {
2326                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2327                                   length, pnl, type);
2328                         return -EINVAL;
2329                 }
2330                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2331                 if (length != 14 + pnl + pdl) {
2332                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2333                                   length, pnl, pdl, type);
2334                         return -EINVAL;
2335                 }
2336                 ++ffs->ms_os_descs_ext_prop_count;
2337                 /* property name reported to the host as "WCHAR"s */
2338                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2339                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2340         }
2341                 break;
2342         default:
2343                 pr_vdebug("unknown descriptor: %d\n", type);
2344                 return -EINVAL;
2345         }
2346         return length;
2347 }
2348
2349 static int __ffs_data_got_descs(struct ffs_data *ffs,
2350                                 char *const _data, size_t len)
2351 {
2352         char *data = _data, *raw_descs;
2353         unsigned os_descs_count = 0, counts[3], flags;
2354         int ret = -EINVAL, i;
2355         struct ffs_desc_helper helper;
2356
2357         ENTER();
2358
2359         if (get_unaligned_le32(data + 4) != len)
2360                 goto error;
2361
2362         switch (get_unaligned_le32(data)) {
2363         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2364                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2365                 data += 8;
2366                 len  -= 8;
2367                 break;
2368         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2369                 flags = get_unaligned_le32(data + 8);
2370                 ffs->user_flags = flags;
2371                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2372                               FUNCTIONFS_HAS_HS_DESC |
2373                               FUNCTIONFS_HAS_SS_DESC |
2374                               FUNCTIONFS_HAS_MS_OS_DESC |
2375                               FUNCTIONFS_VIRTUAL_ADDR |
2376                               FUNCTIONFS_EVENTFD |
2377                               FUNCTIONFS_ALL_CTRL_RECIP |
2378                               FUNCTIONFS_CONFIG0_SETUP)) {
2379                         ret = -ENOSYS;
2380                         goto error;
2381                 }
2382                 data += 12;
2383                 len  -= 12;
2384                 break;
2385         default:
2386                 goto error;
2387         }
2388
2389         if (flags & FUNCTIONFS_EVENTFD) {
2390                 if (len < 4)
2391                         goto error;
2392                 ffs->ffs_eventfd =
2393                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2394                 if (IS_ERR(ffs->ffs_eventfd)) {
2395                         ret = PTR_ERR(ffs->ffs_eventfd);
2396                         ffs->ffs_eventfd = NULL;
2397                         goto error;
2398                 }
2399                 data += 4;
2400                 len  -= 4;
2401         }
2402
2403         /* Read fs_count, hs_count and ss_count (if present) */
2404         for (i = 0; i < 3; ++i) {
2405                 if (!(flags & (1 << i))) {
2406                         counts[i] = 0;
2407                 } else if (len < 4) {
2408                         goto error;
2409                 } else {
2410                         counts[i] = get_unaligned_le32(data);
2411                         data += 4;
2412                         len  -= 4;
2413                 }
2414         }
2415         if (flags & (1 << i)) {
2416                 if (len < 4) {
2417                         goto error;
2418                 }
2419                 os_descs_count = get_unaligned_le32(data);
2420                 data += 4;
2421                 len -= 4;
2422         };
2423
2424         /* Read descriptors */
2425         raw_descs = data;
2426         helper.ffs = ffs;
2427         for (i = 0; i < 3; ++i) {
2428                 if (!counts[i])
2429                         continue;
2430                 helper.interfaces_count = 0;
2431                 helper.eps_count = 0;
2432                 ret = ffs_do_descs(counts[i], data, len,
2433                                    __ffs_data_do_entity, &helper);
2434                 if (ret < 0)
2435                         goto error;
2436                 if (!ffs->eps_count && !ffs->interfaces_count) {
2437                         ffs->eps_count = helper.eps_count;
2438                         ffs->interfaces_count = helper.interfaces_count;
2439                 } else {
2440                         if (ffs->eps_count != helper.eps_count) {
2441                                 ret = -EINVAL;
2442                                 goto error;
2443                         }
2444                         if (ffs->interfaces_count != helper.interfaces_count) {
2445                                 ret = -EINVAL;
2446                                 goto error;
2447                         }
2448                 }
2449                 data += ret;
2450                 len  -= ret;
2451         }
2452         if (os_descs_count) {
2453                 ret = ffs_do_os_descs(os_descs_count, data, len,
2454                                       __ffs_data_do_os_desc, ffs);
2455                 if (ret < 0)
2456                         goto error;
2457                 data += ret;
2458                 len -= ret;
2459         }
2460
2461         if (raw_descs == data || len) {
2462                 ret = -EINVAL;
2463                 goto error;
2464         }
2465
2466         ffs->raw_descs_data     = _data;
2467         ffs->raw_descs          = raw_descs;
2468         ffs->raw_descs_length   = data - raw_descs;
2469         ffs->fs_descs_count     = counts[0];
2470         ffs->hs_descs_count     = counts[1];
2471         ffs->ss_descs_count     = counts[2];
2472         ffs->ms_os_descs_count  = os_descs_count;
2473
2474         return 0;
2475
2476 error:
2477         kfree(_data);
2478         return ret;
2479 }
2480
2481 static int __ffs_data_got_strings(struct ffs_data *ffs,
2482                                   char *const _data, size_t len)
2483 {
2484         u32 str_count, needed_count, lang_count;
2485         struct usb_gadget_strings **stringtabs, *t;
2486         const char *data = _data;
2487         struct usb_string *s;
2488
2489         ENTER();
2490
2491         if (unlikely(len < 16 ||
2492                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2493                      get_unaligned_le32(data + 4) != len))
2494                 goto error;
2495         str_count  = get_unaligned_le32(data + 8);
2496         lang_count = get_unaligned_le32(data + 12);
2497
2498         /* if one is zero the other must be zero */
2499         if (unlikely(!str_count != !lang_count))
2500                 goto error;
2501
2502         /* Do we have at least as many strings as descriptors need? */
2503         needed_count = ffs->strings_count;
2504         if (unlikely(str_count < needed_count))
2505                 goto error;
2506
2507         /*
2508          * If we don't need any strings just return and free all
2509          * memory.
2510          */
2511         if (!needed_count) {
2512                 kfree(_data);
2513                 return 0;
2514         }
2515
2516         /* Allocate everything in one chunk so there's less maintenance. */
2517         {
2518                 unsigned i = 0;
2519                 vla_group(d);
2520                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2521                         lang_count + 1);
2522                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2523                 vla_item(d, struct usb_string, strings,
2524                         lang_count*(needed_count+1));
2525
2526                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2527
2528                 if (unlikely(!vlabuf)) {
2529                         kfree(_data);
2530                         return -ENOMEM;
2531                 }
2532
2533                 /* Initialize the VLA pointers */
2534                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2535                 t = vla_ptr(vlabuf, d, stringtab);
2536                 i = lang_count;
2537                 do {
2538                         *stringtabs++ = t++;
2539                 } while (--i);
2540                 *stringtabs = NULL;
2541
2542                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2543                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2544                 t = vla_ptr(vlabuf, d, stringtab);
2545                 s = vla_ptr(vlabuf, d, strings);
2546         }
2547
2548         /* For each language */
2549         data += 16;
2550         len -= 16;
2551
2552         do { /* lang_count > 0 so we can use do-while */
2553                 unsigned needed = needed_count;
2554
2555                 if (unlikely(len < 3))
2556                         goto error_free;
2557                 t->language = get_unaligned_le16(data);
2558                 t->strings  = s;
2559                 ++t;
2560
2561                 data += 2;
2562                 len -= 2;
2563
2564                 /* For each string */
2565                 do { /* str_count > 0 so we can use do-while */
2566                         size_t length = strnlen(data, len);
2567
2568                         if (unlikely(length == len))
2569                                 goto error_free;
2570
2571                         /*
2572                          * User may provide more strings then we need,
2573                          * if that's the case we simply ignore the
2574                          * rest
2575                          */
2576                         if (likely(needed)) {
2577                                 /*
2578                                  * s->id will be set while adding
2579                                  * function to configuration so for
2580                                  * now just leave garbage here.
2581                                  */
2582                                 s->s = data;
2583                                 --needed;
2584                                 ++s;
2585                         }
2586
2587                         data += length + 1;
2588                         len -= length + 1;
2589                 } while (--str_count);
2590
2591                 s->id = 0;   /* terminator */
2592                 s->s = NULL;
2593                 ++s;
2594
2595         } while (--lang_count);
2596
2597         /* Some garbage left? */
2598         if (unlikely(len))
2599                 goto error_free;
2600
2601         /* Done! */
2602         ffs->stringtabs = stringtabs;
2603         ffs->raw_strings = _data;
2604
2605         return 0;
2606
2607 error_free:
2608         kfree(stringtabs);
2609 error:
2610         kfree(_data);
2611         return -EINVAL;
2612 }
2613
2614
2615 /* Events handling and management *******************************************/
2616
2617 static void __ffs_event_add(struct ffs_data *ffs,
2618                             enum usb_functionfs_event_type type)
2619 {
2620         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2621         int neg = 0;
2622
2623         /*
2624          * Abort any unhandled setup
2625          *
2626          * We do not need to worry about some cmpxchg() changing value
2627          * of ffs->setup_state without holding the lock because when
2628          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2629          * the source does nothing.
2630          */
2631         if (ffs->setup_state == FFS_SETUP_PENDING)
2632                 ffs->setup_state = FFS_SETUP_CANCELLED;
2633
2634         /*
2635          * Logic of this function guarantees that there are at most four pending
2636          * evens on ffs->ev.types queue.  This is important because the queue
2637          * has space for four elements only and __ffs_ep0_read_events function
2638          * depends on that limit as well.  If more event types are added, those
2639          * limits have to be revisited or guaranteed to still hold.
2640          */
2641         switch (type) {
2642         case FUNCTIONFS_RESUME:
2643                 rem_type2 = FUNCTIONFS_SUSPEND;
2644                 /* FALL THROUGH */
2645         case FUNCTIONFS_SUSPEND:
2646         case FUNCTIONFS_SETUP:
2647                 rem_type1 = type;
2648                 /* Discard all similar events */
2649                 break;
2650
2651         case FUNCTIONFS_BIND:
2652         case FUNCTIONFS_UNBIND:
2653         case FUNCTIONFS_DISABLE:
2654         case FUNCTIONFS_ENABLE:
2655                 /* Discard everything other then power management. */
2656                 rem_type1 = FUNCTIONFS_SUSPEND;
2657                 rem_type2 = FUNCTIONFS_RESUME;
2658                 neg = 1;
2659                 break;
2660
2661         default:
2662                 WARN(1, "%d: unknown event, this should not happen\n", type);
2663                 return;
2664         }
2665
2666         {
2667                 u8 *ev  = ffs->ev.types, *out = ev;
2668                 unsigned n = ffs->ev.count;
2669                 for (; n; --n, ++ev)
2670                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2671                                 *out++ = *ev;
2672                         else
2673                                 pr_vdebug("purging event %d\n", *ev);
2674                 ffs->ev.count = out - ffs->ev.types;
2675         }
2676
2677         pr_vdebug("adding event %d\n", type);
2678         ffs->ev.types[ffs->ev.count++] = type;
2679         wake_up_locked(&ffs->ev.waitq);
2680         if (ffs->ffs_eventfd)
2681                 eventfd_signal(ffs->ffs_eventfd, 1);
2682 }
2683
2684 static void ffs_event_add(struct ffs_data *ffs,
2685                           enum usb_functionfs_event_type type)
2686 {
2687         unsigned long flags;
2688         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2689         __ffs_event_add(ffs, type);
2690         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2691 }
2692
2693 /* Bind/unbind USB function hooks *******************************************/
2694
2695 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2696 {
2697         int i;
2698
2699         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2700                 if (ffs->eps_addrmap[i] == endpoint_address)
2701                         return i;
2702         return -ENOENT;
2703 }
2704
2705 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2706                                     struct usb_descriptor_header *desc,
2707                                     void *priv)
2708 {
2709         struct usb_endpoint_descriptor *ds = (void *)desc;
2710         struct ffs_function *func = priv;
2711         struct ffs_ep *ffs_ep;
2712         unsigned ep_desc_id;
2713         int idx;
2714         static const char *speed_names[] = { "full", "high", "super" };
2715
2716         if (type != FFS_DESCRIPTOR)
2717                 return 0;
2718
2719         /*
2720          * If ss_descriptors is not NULL, we are reading super speed
2721          * descriptors; if hs_descriptors is not NULL, we are reading high
2722          * speed descriptors; otherwise, we are reading full speed
2723          * descriptors.
2724          */
2725         if (func->function.ss_descriptors) {
2726                 ep_desc_id = 2;
2727                 func->function.ss_descriptors[(long)valuep] = desc;
2728         } else if (func->function.hs_descriptors) {
2729                 ep_desc_id = 1;
2730                 func->function.hs_descriptors[(long)valuep] = desc;
2731         } else {
2732                 ep_desc_id = 0;
2733                 func->function.fs_descriptors[(long)valuep]    = desc;
2734         }
2735
2736         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2737                 return 0;
2738
2739         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2740         if (idx < 0)
2741                 return idx;
2742
2743         ffs_ep = func->eps + idx;
2744
2745         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2746                 pr_err("two %sspeed descriptors for EP %d\n",
2747                           speed_names[ep_desc_id],
2748                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2749                 return -EINVAL;
2750         }
2751         ffs_ep->descs[ep_desc_id] = ds;
2752
2753         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2754         if (ffs_ep->ep) {
2755                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2756                 if (!ds->wMaxPacketSize)
2757                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2758         } else {
2759                 struct usb_request *req;
2760                 struct usb_ep *ep;
2761                 u8 bEndpointAddress;
2762
2763                 /*
2764                  * We back up bEndpointAddress because autoconfig overwrites
2765                  * it with physical endpoint address.
2766                  */
2767                 bEndpointAddress = ds->bEndpointAddress;
2768                 pr_vdebug("autoconfig\n");
2769                 ep = usb_ep_autoconfig(func->gadget, ds);
2770                 if (unlikely(!ep))
2771                         return -ENOTSUPP;
2772                 ep->driver_data = func->eps + idx;
2773
2774                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2775                 if (unlikely(!req))
2776                         return -ENOMEM;
2777
2778                 ffs_ep->ep  = ep;
2779                 ffs_ep->req = req;
2780                 func->eps_revmap[ds->bEndpointAddress &
2781                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2782                 /*
2783                  * If we use virtual address mapping, we restore
2784                  * original bEndpointAddress value.
2785                  */
2786                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2787                         ds->bEndpointAddress = bEndpointAddress;
2788         }
2789         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2790
2791         return 0;
2792 }
2793
2794 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2795                                    struct usb_descriptor_header *desc,
2796                                    void *priv)
2797 {
2798         struct ffs_function *func = priv;
2799         unsigned idx;
2800         u8 newValue;
2801
2802         switch (type) {
2803         default:
2804         case FFS_DESCRIPTOR:
2805                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2806                 return 0;
2807
2808         case FFS_INTERFACE:
2809                 idx = *valuep;
2810                 if (func->interfaces_nums[idx] < 0) {
2811                         int id = usb_interface_id(func->conf, &func->function);
2812                         if (unlikely(id < 0))
2813                                 return id;
2814                         func->interfaces_nums[idx] = id;
2815                 }
2816                 newValue = func->interfaces_nums[idx];
2817                 break;
2818
2819         case FFS_STRING:
2820                 /* String' IDs are allocated when fsf_data is bound to cdev */
2821                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2822                 break;
2823
2824         case FFS_ENDPOINT:
2825                 /*
2826                  * USB_DT_ENDPOINT are handled in
2827                  * __ffs_func_bind_do_descs().
2828                  */
2829                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2830                         return 0;
2831
2832                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2833                 if (unlikely(!func->eps[idx].ep))
2834                         return -EINVAL;
2835
2836                 {
2837                         struct usb_endpoint_descriptor **descs;
2838                         descs = func->eps[idx].descs;
2839                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2840                 }
2841                 break;
2842         }
2843
2844         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2845         *valuep = newValue;
2846         return 0;
2847 }
2848
2849 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2850                                       struct usb_os_desc_header *h, void *data,
2851                                       unsigned len, void *priv)
2852 {
2853         struct ffs_function *func = priv;
2854         u8 length = 0;
2855
2856         switch (type) {
2857         case FFS_OS_DESC_EXT_COMPAT: {
2858                 struct usb_ext_compat_desc *desc = data;
2859                 struct usb_os_desc_table *t;
2860
2861                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2862                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2863                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2864                        ARRAY_SIZE(desc->CompatibleID) +
2865                        ARRAY_SIZE(desc->SubCompatibleID));
2866                 length = sizeof(*desc);
2867         }
2868                 break;
2869         case FFS_OS_DESC_EXT_PROP: {
2870                 struct usb_ext_prop_desc *desc = data;
2871                 struct usb_os_desc_table *t;
2872                 struct usb_os_desc_ext_prop *ext_prop;
2873                 char *ext_prop_name;
2874                 char *ext_prop_data;
2875
2876                 t = &func->function.os_desc_table[h->interface];
2877                 t->if_id = func->interfaces_nums[h->interface];
2878
2879                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2880                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2881
2882                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2883                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2884                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2885                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2886                 length = ext_prop->name_len + ext_prop->data_len + 14;
2887
2888                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2889                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2890                         ext_prop->name_len;
2891
2892                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2893                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2894                         ext_prop->data_len;
2895                 memcpy(ext_prop_data,
2896                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2897                        ext_prop->data_len);
2898                 /* unicode data reported to the host as "WCHAR"s */
2899                 switch (ext_prop->type) {
2900                 case USB_EXT_PROP_UNICODE:
2901                 case USB_EXT_PROP_UNICODE_ENV:
2902                 case USB_EXT_PROP_UNICODE_LINK:
2903                 case USB_EXT_PROP_UNICODE_MULTI:
2904                         ext_prop->data_len *= 2;
2905                         break;
2906                 }
2907                 ext_prop->data = ext_prop_data;
2908
2909                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2910                        ext_prop->name_len);
2911                 /* property name reported to the host as "WCHAR"s */
2912                 ext_prop->name_len *= 2;
2913                 ext_prop->name = ext_prop_name;
2914
2915                 t->os_desc->ext_prop_len +=
2916                         ext_prop->name_len + ext_prop->data_len + 14;
2917                 ++t->os_desc->ext_prop_count;
2918                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2919         }
2920                 break;
2921         default:
2922                 pr_vdebug("unknown descriptor: %d\n", type);
2923         }
2924
2925         return length;
2926 }
2927
2928 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2929                                                 struct usb_configuration *c)
2930 {
2931         struct ffs_function *func = ffs_func_from_usb(f);
2932         struct f_fs_opts *ffs_opts =
2933                 container_of(f->fi, struct f_fs_opts, func_inst);
2934         int ret;
2935
2936         ENTER();
2937
2938         /*
2939          * Legacy gadget triggers binding in functionfs_ready_callback,
2940          * which already uses locking; taking the same lock here would
2941          * cause a deadlock.
2942          *
2943          * Configfs-enabled gadgets however do need ffs_dev_lock.
2944          */
2945         if (!ffs_opts->no_configfs)
2946                 ffs_dev_lock();
2947         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2948         func->ffs = ffs_opts->dev->ffs_data;
2949         if (!ffs_opts->no_configfs)
2950                 ffs_dev_unlock();
2951         if (ret)
2952                 return ERR_PTR(ret);
2953
2954         func->conf = c;
2955         func->gadget = c->cdev->gadget;
2956
2957         /*
2958          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2959          * configurations are bound in sequence with list_for_each_entry,
2960          * in each configuration its functions are bound in sequence
2961          * with list_for_each_entry, so we assume no race condition
2962          * with regard to ffs_opts->bound access
2963          */
2964         if (!ffs_opts->refcnt) {
2965                 ret = functionfs_bind(func->ffs, c->cdev);
2966                 if (ret)
2967                         return ERR_PTR(ret);
2968         }
2969         ffs_opts->refcnt++;
2970         func->function.strings = func->ffs->stringtabs;
2971
2972         return ffs_opts;
2973 }
2974
2975 static int _ffs_func_bind(struct usb_configuration *c,
2976                           struct usb_function *f)
2977 {
2978         struct ffs_function *func = ffs_func_from_usb(f);
2979         struct ffs_data *ffs = func->ffs;
2980
2981         const int full = !!func->ffs->fs_descs_count;
2982         const int high = !!func->ffs->hs_descs_count;
2983         const int super = !!func->ffs->ss_descs_count;
2984
2985         int fs_len, hs_len, ss_len, ret, i;
2986         struct ffs_ep *eps_ptr;
2987
2988         /* Make it a single chunk, less management later on */
2989         vla_group(d);
2990         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2991         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2992                 full ? ffs->fs_descs_count + 1 : 0);
2993         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2994                 high ? ffs->hs_descs_count + 1 : 0);
2995         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2996                 super ? ffs->ss_descs_count + 1 : 0);
2997         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2998         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2999                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3000         vla_item_with_sz(d, char[16], ext_compat,
3001                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3002         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3003                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3004         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3005                          ffs->ms_os_descs_ext_prop_count);
3006         vla_item_with_sz(d, char, ext_prop_name,
3007                          ffs->ms_os_descs_ext_prop_name_len);
3008         vla_item_with_sz(d, char, ext_prop_data,
3009                          ffs->ms_os_descs_ext_prop_data_len);
3010         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3011         char *vlabuf;
3012
3013         ENTER();
3014
3015         /* Has descriptors only for speeds gadget does not support */
3016         if (unlikely(!(full | high | super)))
3017                 return -ENOTSUPP;
3018
3019         /* Allocate a single chunk, less management later on */
3020         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3021         if (unlikely(!vlabuf))
3022                 return -ENOMEM;
3023
3024         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3025         ffs->ms_os_descs_ext_prop_name_avail =
3026                 vla_ptr(vlabuf, d, ext_prop_name);
3027         ffs->ms_os_descs_ext_prop_data_avail =
3028                 vla_ptr(vlabuf, d, ext_prop_data);
3029
3030         /* Copy descriptors  */
3031         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3032                ffs->raw_descs_length);
3033
3034         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3035         eps_ptr = vla_ptr(vlabuf, d, eps);
3036         for (i = 0; i < ffs->eps_count; i++)
3037                 eps_ptr[i].num = -1;
3038
3039         /* Save pointers
3040          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3041         */
3042         func->eps             = vla_ptr(vlabuf, d, eps);
3043         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3044
3045         /*
3046          * Go through all the endpoint descriptors and allocate
3047          * endpoints first, so that later we can rewrite the endpoint
3048          * numbers without worrying that it may be described later on.
3049          */
3050         if (likely(full)) {
3051                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3052                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3053                                       vla_ptr(vlabuf, d, raw_descs),
3054                                       d_raw_descs__sz,
3055                                       __ffs_func_bind_do_descs, func);
3056                 if (unlikely(fs_len < 0)) {
3057                         ret = fs_len;
3058                         goto error;
3059                 }
3060         } else {
3061                 fs_len = 0;
3062         }
3063
3064         if (likely(high)) {
3065                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3066                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3067                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3068                                       d_raw_descs__sz - fs_len,
3069                                       __ffs_func_bind_do_descs, func);
3070                 if (unlikely(hs_len < 0)) {
3071                         ret = hs_len;
3072                         goto error;
3073                 }
3074         } else {
3075                 hs_len = 0;
3076         }
3077
3078         if (likely(super)) {
3079                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3080                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3081                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3082                                 d_raw_descs__sz - fs_len - hs_len,
3083                                 __ffs_func_bind_do_descs, func);
3084                 if (unlikely(ss_len < 0)) {
3085                         ret = ss_len;
3086                         goto error;
3087                 }
3088         } else {
3089                 ss_len = 0;
3090         }
3091
3092         /*
3093          * Now handle interface numbers allocation and interface and
3094          * endpoint numbers rewriting.  We can do that in one go
3095          * now.
3096          */
3097         ret = ffs_do_descs(ffs->fs_descs_count +
3098                            (high ? ffs->hs_descs_count : 0) +
3099                            (super ? ffs->ss_descs_count : 0),
3100                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3101                            __ffs_func_bind_do_nums, func);
3102         if (unlikely(ret < 0))
3103                 goto error;
3104
3105         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3106         if (c->cdev->use_os_string) {
3107                 for (i = 0; i < ffs->interfaces_count; ++i) {
3108                         struct usb_os_desc *desc;
3109
3110                         desc = func->function.os_desc_table[i].os_desc =
3111                                 vla_ptr(vlabuf, d, os_desc) +
3112                                 i * sizeof(struct usb_os_desc);
3113                         desc->ext_compat_id =
3114                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3115                         INIT_LIST_HEAD(&desc->ext_prop);
3116                 }
3117                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3118                                       vla_ptr(vlabuf, d, raw_descs) +
3119                                       fs_len + hs_len + ss_len,
3120                                       d_raw_descs__sz - fs_len - hs_len -
3121                                       ss_len,
3122                                       __ffs_func_bind_do_os_desc, func);
3123                 if (unlikely(ret < 0))
3124                         goto error;
3125         }
3126         func->function.os_desc_n =
3127                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3128
3129         /* And we're done */
3130         ffs_event_add(ffs, FUNCTIONFS_BIND);
3131         return 0;
3132
3133 error:
3134         /* XXX Do we need to release all claimed endpoints here? */
3135         return ret;
3136 }
3137
3138 static int ffs_func_bind(struct usb_configuration *c,
3139                          struct usb_function *f)
3140 {
3141         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3142         struct ffs_function *func = ffs_func_from_usb(f);
3143         int ret;
3144
3145         if (IS_ERR(ffs_opts))
3146                 return PTR_ERR(ffs_opts);
3147
3148         ret = _ffs_func_bind(c, f);
3149         if (ret && !--ffs_opts->refcnt)
3150                 functionfs_unbind(func->ffs);
3151
3152         return ret;
3153 }
3154
3155
3156 /* Other USB function hooks *************************************************/
3157
3158 static void ffs_reset_work(struct work_struct *work)
3159 {
3160         struct ffs_data *ffs = container_of(work,
3161                 struct ffs_data, reset_work);
3162         ffs_data_reset(ffs);
3163 }
3164
3165 static int ffs_func_set_alt(struct usb_function *f,
3166                             unsigned interface, unsigned alt)
3167 {
3168         struct ffs_function *func = ffs_func_from_usb(f);
3169         struct ffs_data *ffs = func->ffs;
3170         int ret = 0, intf;
3171
3172         if (alt != (unsigned)-1) {
3173                 intf = ffs_func_revmap_intf(func, interface);
3174                 if (unlikely(intf < 0))
3175                         return intf;
3176         }
3177
3178         if (ffs->func)
3179                 ffs_func_eps_disable(ffs->func);
3180
3181         if (ffs->state == FFS_DEACTIVATED) {
3182                 ffs->state = FFS_CLOSING;
3183                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3184                 schedule_work(&ffs->reset_work);
3185                 return -ENODEV;
3186         }
3187
3188         if (ffs->state != FFS_ACTIVE)
3189                 return -ENODEV;
3190
3191         if (alt == (unsigned)-1) {
3192                 ffs->func = NULL;
3193                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3194                 return 0;
3195         }
3196
3197         ffs->func = func;
3198         ret = ffs_func_eps_enable(func);
3199         if (likely(ret >= 0))
3200                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3201         return ret;
3202 }
3203
3204 static void ffs_func_disable(struct usb_function *f)
3205 {
3206         ffs_func_set_alt(f, 0, (unsigned)-1);
3207 }
3208
3209 static int ffs_func_setup(struct usb_function *f,
3210                           const struct usb_ctrlrequest *creq)
3211 {
3212         struct ffs_function *func = ffs_func_from_usb(f);
3213         struct ffs_data *ffs = func->ffs;
3214         unsigned long flags;
3215         int ret;
3216
3217         ENTER();
3218
3219         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3220         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3221         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3222         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3223         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3224
3225         /*
3226          * Most requests directed to interface go through here
3227          * (notable exceptions are set/get interface) so we need to
3228          * handle them.  All other either handled by composite or
3229          * passed to usb_configuration->setup() (if one is set).  No
3230          * matter, we will handle requests directed to endpoint here
3231          * as well (as it's straightforward).  Other request recipient
3232          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3233          * is being used.
3234          */
3235         if (ffs->state != FFS_ACTIVE)
3236                 return -ENODEV;
3237
3238         switch (creq->bRequestType & USB_RECIP_MASK) {
3239         case USB_RECIP_INTERFACE:
3240                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3241                 if (unlikely(ret < 0))
3242                         return ret;
3243                 break;
3244
3245         case USB_RECIP_ENDPOINT:
3246                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3247                 if (unlikely(ret < 0))
3248                         return ret;
3249                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3250                         ret = func->ffs->eps_addrmap[ret];
3251                 break;
3252
3253         default:
3254                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3255                         ret = le16_to_cpu(creq->wIndex);
3256                 else
3257                         return -EOPNOTSUPP;
3258         }
3259
3260         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3261         ffs->ev.setup = *creq;
3262         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3263         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3264         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3265
3266         return USB_GADGET_DELAYED_STATUS;
3267 }
3268
3269 static bool ffs_func_req_match(struct usb_function *f,
3270                                const struct usb_ctrlrequest *creq,
3271                                bool config0)
3272 {
3273         struct ffs_function *func = ffs_func_from_usb(f);
3274
3275         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3276                 return false;
3277
3278         switch (creq->bRequestType & USB_RECIP_MASK) {
3279         case USB_RECIP_INTERFACE:
3280                 return (ffs_func_revmap_intf(func,
3281                                              le16_to_cpu(creq->wIndex)) >= 0);
3282         case USB_RECIP_ENDPOINT:
3283                 return (ffs_func_revmap_ep(func,
3284                                            le16_to_cpu(creq->wIndex)) >= 0);
3285         default:
3286                 return (bool) (func->ffs->user_flags &
3287                                FUNCTIONFS_ALL_CTRL_RECIP);
3288         }
3289 }
3290
3291 static void ffs_func_suspend(struct usb_function *f)
3292 {
3293         ENTER();
3294         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3295 }
3296
3297 static void ffs_func_resume(struct usb_function *f)
3298 {
3299         ENTER();
3300         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3301 }
3302
3303
3304 /* Endpoint and interface numbers reverse mapping ***************************/
3305
3306 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3307 {
3308         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3309         return num ? num : -EDOM;
3310 }
3311
3312 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3313 {
3314         short *nums = func->interfaces_nums;
3315         unsigned count = func->ffs->interfaces_count;
3316
3317         for (; count; --count, ++nums) {
3318                 if (*nums >= 0 && *nums == intf)
3319                         return nums - func->interfaces_nums;
3320         }
3321
3322         return -EDOM;
3323 }
3324
3325
3326 /* Devices management *******************************************************/
3327
3328 static LIST_HEAD(ffs_devices);
3329
3330 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3331 {
3332         struct ffs_dev *dev;
3333
3334         if (!name)
3335                 return NULL;
3336
3337         list_for_each_entry(dev, &ffs_devices, entry) {
3338                 if (strcmp(dev->name, name) == 0)
3339                         return dev;
3340         }
3341
3342         return NULL;
3343 }
3344
3345 /*
3346  * ffs_lock must be taken by the caller of this function
3347  */
3348 static struct ffs_dev *_ffs_get_single_dev(void)
3349 {
3350         struct ffs_dev *dev;
3351
3352         if (list_is_singular(&ffs_devices)) {
3353                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3354                 if (dev->single)
3355                         return dev;
3356         }
3357
3358         return NULL;
3359 }
3360
3361 /*
3362  * ffs_lock must be taken by the caller of this function
3363  */
3364 static struct ffs_dev *_ffs_find_dev(const char *name)
3365 {
3366         struct ffs_dev *dev;
3367
3368         dev = _ffs_get_single_dev();
3369         if (dev)
3370                 return dev;
3371
3372         return _ffs_do_find_dev(name);
3373 }
3374
3375 /* Configfs support *********************************************************/
3376
3377 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3378 {
3379         return container_of(to_config_group(item), struct f_fs_opts,
3380                             func_inst.group);
3381 }
3382
3383 static void ffs_attr_release(struct config_item *item)
3384 {
3385         struct f_fs_opts *opts = to_ffs_opts(item);
3386
3387         usb_put_function_instance(&opts->func_inst);
3388 }
3389
3390 static struct configfs_item_operations ffs_item_ops = {
3391         .release        = ffs_attr_release,
3392 };
3393
3394 static const struct config_item_type ffs_func_type = {
3395         .ct_item_ops    = &ffs_item_ops,
3396         .ct_owner       = THIS_MODULE,
3397 };
3398
3399
3400 /* Function registration interface ******************************************/
3401
3402 static void ffs_free_inst(struct usb_function_instance *f)
3403 {
3404         struct f_fs_opts *opts;
3405
3406         opts = to_f_fs_opts(f);
3407         ffs_dev_lock();
3408         _ffs_free_dev(opts->dev);
3409         ffs_dev_unlock();
3410         kfree(opts);
3411 }
3412
3413 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3414 {
3415         if (strlen(name) >= FIELD_SIZEOF(struct ffs_dev, name))
3416                 return -ENAMETOOLONG;
3417         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3418 }
3419
3420 static struct usb_function_instance *ffs_alloc_inst(void)
3421 {
3422         struct f_fs_opts *opts;
3423         struct ffs_dev *dev;
3424
3425         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3426         if (!opts)
3427                 return ERR_PTR(-ENOMEM);
3428
3429         opts->func_inst.set_inst_name = ffs_set_inst_name;
3430         opts->func_inst.free_func_inst = ffs_free_inst;
3431         ffs_dev_lock();
3432         dev = _ffs_alloc_dev();
3433         ffs_dev_unlock();
3434         if (IS_ERR(dev)) {
3435                 kfree(opts);
3436                 return ERR_CAST(dev);
3437         }
3438         opts->dev = dev;
3439         dev->opts = opts;
3440
3441         config_group_init_type_name(&opts->func_inst.group, "",
3442                                     &ffs_func_type);
3443         return &opts->func_inst;
3444 }
3445
3446 static void ffs_free(struct usb_function *f)
3447 {
3448         kfree(ffs_func_from_usb(f));
3449 }
3450
3451 static void ffs_func_unbind(struct usb_configuration *c,
3452                             struct usb_function *f)
3453 {
3454         struct ffs_function *func = ffs_func_from_usb(f);
3455         struct ffs_data *ffs = func->ffs;
3456         struct f_fs_opts *opts =
3457                 container_of(f->fi, struct f_fs_opts, func_inst);
3458         struct ffs_ep *ep = func->eps;
3459         unsigned count = ffs->eps_count;
3460         unsigned long flags;
3461
3462         ENTER();
3463         if (ffs->func == func) {
3464                 ffs_func_eps_disable(func);
3465                 ffs->func = NULL;
3466         }
3467
3468         if (!--opts->refcnt)
3469                 functionfs_unbind(ffs);
3470
3471         /* cleanup after autoconfig */
3472         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3473         while (count--) {
3474                 if (ep->ep && ep->req)
3475                         usb_ep_free_request(ep->ep, ep->req);
3476                 ep->req = NULL;
3477                 ++ep;
3478         }
3479         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3480         kfree(func->eps);
3481         func->eps = NULL;
3482         /*
3483          * eps, descriptors and interfaces_nums are allocated in the
3484          * same chunk so only one free is required.
3485          */
3486         func->function.fs_descriptors = NULL;
3487         func->function.hs_descriptors = NULL;
3488         func->function.ss_descriptors = NULL;
3489         func->interfaces_nums = NULL;
3490
3491         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3492 }
3493
3494 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3495 {
3496         struct ffs_function *func;
3497
3498         ENTER();
3499
3500         func = kzalloc(sizeof(*func), GFP_KERNEL);
3501         if (unlikely(!func))
3502                 return ERR_PTR(-ENOMEM);
3503
3504         func->function.name    = "Function FS Gadget";
3505
3506         func->function.bind    = ffs_func_bind;
3507         func->function.unbind  = ffs_func_unbind;
3508         func->function.set_alt = ffs_func_set_alt;
3509         func->function.disable = ffs_func_disable;
3510         func->function.setup   = ffs_func_setup;
3511         func->function.req_match = ffs_func_req_match;
3512         func->function.suspend = ffs_func_suspend;
3513         func->function.resume  = ffs_func_resume;
3514         func->function.free_func = ffs_free;
3515
3516         return &func->function;
3517 }
3518
3519 /*
3520  * ffs_lock must be taken by the caller of this function
3521  */
3522 static struct ffs_dev *_ffs_alloc_dev(void)
3523 {
3524         struct ffs_dev *dev;
3525         int ret;
3526
3527         if (_ffs_get_single_dev())
3528                         return ERR_PTR(-EBUSY);
3529
3530         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3531         if (!dev)
3532                 return ERR_PTR(-ENOMEM);
3533
3534         if (list_empty(&ffs_devices)) {
3535                 ret = functionfs_init();
3536                 if (ret) {
3537                         kfree(dev);
3538                         return ERR_PTR(ret);
3539                 }
3540         }
3541
3542         list_add(&dev->entry, &ffs_devices);
3543
3544         return dev;
3545 }
3546
3547 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3548 {
3549         struct ffs_dev *existing;
3550         int ret = 0;
3551
3552         ffs_dev_lock();
3553
3554         existing = _ffs_do_find_dev(name);
3555         if (!existing)
3556                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3557         else if (existing != dev)
3558                 ret = -EBUSY;
3559
3560         ffs_dev_unlock();
3561
3562         return ret;
3563 }
3564 EXPORT_SYMBOL_GPL(ffs_name_dev);
3565
3566 int ffs_single_dev(struct ffs_dev *dev)
3567 {
3568         int ret;
3569
3570         ret = 0;
3571         ffs_dev_lock();
3572
3573         if (!list_is_singular(&ffs_devices))
3574                 ret = -EBUSY;
3575         else
3576                 dev->single = true;
3577
3578         ffs_dev_unlock();
3579         return ret;
3580 }
3581 EXPORT_SYMBOL_GPL(ffs_single_dev);
3582
3583 /*
3584  * ffs_lock must be taken by the caller of this function
3585  */
3586 static void _ffs_free_dev(struct ffs_dev *dev)
3587 {
3588         list_del(&dev->entry);
3589
3590         /* Clear the private_data pointer to stop incorrect dev access */
3591         if (dev->ffs_data)
3592                 dev->ffs_data->private_data = NULL;
3593
3594         kfree(dev);
3595         if (list_empty(&ffs_devices))
3596                 functionfs_cleanup();
3597 }
3598
3599 static void *ffs_acquire_dev(const char *dev_name)
3600 {
3601         struct ffs_dev *ffs_dev;
3602
3603         ENTER();
3604         ffs_dev_lock();
3605
3606         ffs_dev = _ffs_find_dev(dev_name);
3607         if (!ffs_dev)
3608                 ffs_dev = ERR_PTR(-ENOENT);
3609         else if (ffs_dev->mounted)
3610                 ffs_dev = ERR_PTR(-EBUSY);
3611         else if (ffs_dev->ffs_acquire_dev_callback &&
3612             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3613                 ffs_dev = ERR_PTR(-ENOENT);
3614         else
3615                 ffs_dev->mounted = true;
3616
3617         ffs_dev_unlock();
3618         return ffs_dev;
3619 }
3620
3621 static void ffs_release_dev(struct ffs_data *ffs_data)
3622 {
3623         struct ffs_dev *ffs_dev;
3624
3625         ENTER();
3626         ffs_dev_lock();
3627
3628         ffs_dev = ffs_data->private_data;
3629         if (ffs_dev) {
3630                 ffs_dev->mounted = false;
3631
3632                 if (ffs_dev->ffs_release_dev_callback)
3633                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3634         }
3635
3636         ffs_dev_unlock();
3637 }
3638
3639 static int ffs_ready(struct ffs_data *ffs)
3640 {
3641         struct ffs_dev *ffs_obj;
3642         int ret = 0;
3643
3644         ENTER();
3645         ffs_dev_lock();
3646
3647         ffs_obj = ffs->private_data;
3648         if (!ffs_obj) {
3649                 ret = -EINVAL;
3650                 goto done;
3651         }
3652         if (WARN_ON(ffs_obj->desc_ready)) {
3653                 ret = -EBUSY;
3654                 goto done;
3655         }
3656
3657         ffs_obj->desc_ready = true;
3658         ffs_obj->ffs_data = ffs;
3659
3660         if (ffs_obj->ffs_ready_callback) {
3661                 ret = ffs_obj->ffs_ready_callback(ffs);
3662                 if (ret)
3663                         goto done;
3664         }
3665
3666         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3667 done:
3668         ffs_dev_unlock();
3669         return ret;
3670 }
3671
3672 static void ffs_closed(struct ffs_data *ffs)
3673 {
3674         struct ffs_dev *ffs_obj;
3675         struct f_fs_opts *opts;
3676         struct config_item *ci;
3677
3678         ENTER();
3679         ffs_dev_lock();
3680
3681         ffs_obj = ffs->private_data;
3682         if (!ffs_obj)
3683                 goto done;
3684
3685         ffs_obj->desc_ready = false;
3686         ffs_obj->ffs_data = NULL;
3687
3688         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3689             ffs_obj->ffs_closed_callback)
3690                 ffs_obj->ffs_closed_callback(ffs);
3691
3692         if (ffs_obj->opts)
3693                 opts = ffs_obj->opts;
3694         else
3695                 goto done;
3696
3697         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3698             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3699                 goto done;
3700
3701         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3702         ffs_dev_unlock();
3703
3704         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3705                 unregister_gadget_item(ci);
3706         return;
3707 done:
3708         ffs_dev_unlock();
3709 }
3710
3711 /* Misc helper functions ****************************************************/
3712
3713 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3714 {
3715         return nonblock
3716                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3717                 : mutex_lock_interruptible(mutex);
3718 }
3719
3720 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3721 {
3722         char *data;
3723
3724         if (unlikely(!len))
3725                 return NULL;
3726
3727         data = kmalloc(len, GFP_KERNEL);
3728         if (unlikely(!data))
3729                 return ERR_PTR(-ENOMEM);
3730
3731         if (unlikely(copy_from_user(data, buf, len))) {
3732                 kfree(data);
3733                 return ERR_PTR(-EFAULT);
3734         }
3735
3736         pr_vdebug("Buffer from user space:\n");
3737         ffs_dump_mem("", data, len);
3738
3739         return data;
3740 }
3741
3742 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3743 MODULE_LICENSE("GPL");
3744 MODULE_AUTHOR("Michal Nazarewicz");