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/mm.h>
  22 #include <linux/module.h>
  23 #include <linux/scatterlist.h>
  24 #include <linux/sched/signal.h>
  25 #include <linux/uio.h>
  26 #include <linux/vmalloc.h>
  27 #include <asm/unaligned.h>
  28
  29 #include <linux/usb/ccid.h>
  30 #include <linux/usb/composite.h>
  31 #include <linux/usb/functionfs.h>
  32
  33 #include <linux/aio.h>
  34 #include <linux/mmu_context.h>
  35 #include <linux/poll.h>
  36 #include <linux/eventfd.h>
  37
  38 #include "u_fs.h"
  39 #include "u_f.h"
  40 #include "u_os_desc.h"
  41 #include "configfs.h"
  42
  43 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  44
  45 /* Reference counter handling */
  46 static void ffs_data_get(struct ffs_data *ffs);
  47 static void ffs_data_put(struct ffs_data *ffs);
  48 /* Creates new ffs_data object. */
  49 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  50         __attribute__((malloc));
  51
  52 /* Opened counter handling. */
  53 static void ffs_data_opened(struct ffs_data *ffs);
  54 static void ffs_data_closed(struct ffs_data *ffs);
  55
  56 /* Called with ffs->mutex held; take over ownership of data. */
  57 static int __must_check
  58 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  59 static int __must_check
  60 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  61
  62
  63 /* The function structure ***************************************************/
  64
  65 struct ffs_ep;
  66
  67 struct ffs_function {
  68         struct usb_configuration        *conf;
  69         struct usb_gadget               *gadget;
  70         struct ffs_data                 *ffs;
  71
  72         struct ffs_ep                   *eps;
  73         u8                              eps_revmap[16];
  74         short                           *interfaces_nums;
  75
  76         struct usb_function             function;
  77 };
  78
  79
  80 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  81 {
  82         return container_of(f, struct ffs_function, function);
  83 }
  84
  85
  86 static inline enum ffs_setup_state
  87 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  88 {
  89         return (enum ffs_setup_state)
  90                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  91 }
  92
  93
  94 static void ffs_func_eps_disable(struct ffs_function *func);
  95 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  96
  97 static int ffs_func_bind(struct usb_configuration *,
  98                          struct usb_function *);
  99 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 100 static void ffs_func_disable(struct usb_function *);
 101 static int ffs_func_setup(struct usb_function *,
 102                           const struct usb_ctrlrequest *);
 103 static bool ffs_func_req_match(struct usb_function *,
 104                                const struct usb_ctrlrequest *,
 105                                bool config0);
 106 static void ffs_func_suspend(struct usb_function *);
 107 static void ffs_func_resume(struct usb_function *);
 108
 109
 110 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 111 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 112
 113
 114 /* The endpoints structures *************************************************/
 115
 116 struct ffs_ep {
 117         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 118         struct usb_request              *req;   /* P: epfile->mutex */
 119
 120         /* [0]: full speed, [1]: high speed, [2]: super speed */
 121         struct usb_endpoint_descriptor  *descs[3];
 122
 123         u8                              num;
 124
 125         int                             status; /* P: epfile->mutex */
 126 };
 127
 128 struct ffs_epfile {
 129         /* Protects ep->ep and ep->req. */
 130         struct mutex                    mutex;
 131
 132         struct ffs_data                 *ffs;
 133         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 134
 135         struct dentry                   *dentry;
 136
 137         /*
 138          * Buffer for holding data from partial reads which may happen since
 139          * we’re rounding user read requests to a multiple of a max packet size.
 140          *
 141          * The pointer is initialised with NULL value and may be set by
 142          * __ffs_epfile_read_data function to point to a temporary buffer.
 143          *
 144          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 145          * data from said buffer and eventually free it.  Importantly, while the
 146          * function is using the buffer, it sets the pointer to NULL.  This is
 147          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 148          * can never run concurrently (they are synchronised by epfile->mutex)
 149          * so the latter will not assign a new value to the pointer.
 150          *
 151          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 152          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 153          * value is crux of the synchronisation between ffs_func_eps_disable and
 154          * __ffs_epfile_read_data.
 155          *
 156          * Once __ffs_epfile_read_data is about to finish it will try to set the
 157          * pointer back to its old value (as described above), but seeing as the
 158          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 159          * the buffer.
 160          *
 161          * == State transitions ==
 162          *
 163          * • ptr == NULL:  (initial state)
 164          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 165          *   ◦ __ffs_epfile_read_buffered:    nop
 166          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 167          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 168          * • ptr == DROP:
 169          *   ◦ __ffs_epfile_read_buffer_free: nop
 170          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 171          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 172          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 173          * • ptr == buf:
 174          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 175          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 176          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 177          *                                    is always called first
 178          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 179          * • ptr == NULL and reading:
 180          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 181          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 182          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 183          *   ◦ reading finishes and …
 184          *     … all data read:               free buf, go to ptr == NULL
 185          *     … otherwise:                   go to ptr == buf and reading
 186          * • ptr == DROP and reading:
 187          *   ◦ __ffs_epfile_read_buffer_free: nop
 188          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 189          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 190          *   ◦ reading finishes:              free buf, go to ptr == DROP
 191          */
 192         struct ffs_buffer               *read_buffer;
 193 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 194
 195         char                            name[5];
 196
 197         unsigned char                   in;     /* P: ffs->eps_lock */
 198         unsigned char                   isoc;   /* P: ffs->eps_lock */
 199
 200         unsigned char                   _pad;
 201 };
 202
 203 struct ffs_buffer {
 204         size_t length;
 205         char *data;
 206         char storage[];
 207 };
 208
 209 /*  ffs_io_data structure ***************************************************/
 210
 211 struct ffs_io_data {
 212         bool aio;
 213         bool read;
 214
 215         struct kiocb *kiocb;
 216         struct iov_iter data;
 217         const void *to_free;
 218         char *buf;
 219
 220         struct mm_struct *mm;
 221         struct work_struct work;
 222
 223         struct usb_ep *ep;
 224         struct usb_request *req;
 225         struct sg_table sgt;
 226         bool use_sg;
 227
 228         struct ffs_data *ffs;
 229 };
 230
 231 struct ffs_desc_helper {
 232         struct ffs_data *ffs;
 233         unsigned interfaces_count;
 234         unsigned eps_count;
 235 };
 236
 237 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 238 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 239
 240 static struct dentry *
 241 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 242                    const struct file_operations *fops);
 243
 244 /* Devices management *******************************************************/
 245
 246 DEFINE_MUTEX(ffs_lock);
 247 EXPORT_SYMBOL_GPL(ffs_lock);
 248
 249 static struct ffs_dev *_ffs_find_dev(const char *name);
 250 static struct ffs_dev *_ffs_alloc_dev(void);
 251 static void _ffs_free_dev(struct ffs_dev *dev);
 252 static void *ffs_acquire_dev(const char *dev_name);
 253 static void ffs_release_dev(struct ffs_data *ffs_data);
 254 static int ffs_ready(struct ffs_data *ffs);
 255 static void ffs_closed(struct ffs_data *ffs);
 256
 257 /* Misc helper functions ****************************************************/
 258
 259 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 260         __attribute__((warn_unused_result, nonnull));
 261 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 262         __attribute__((warn_unused_result, nonnull));
 263
 264
 265 /* Control file aka ep0 *****************************************************/
 266
 267 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 268 {
 269         struct ffs_data *ffs = req->context;
 270
 271         complete(&ffs->ep0req_completion);
 272 }
 273
 274 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 275         __releases(&ffs->ev.waitq.lock)
 276 {
 277         struct usb_request *req = ffs->ep0req;
 278         int ret;
 279
 280         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 281
 282         spin_unlock_irq(&ffs->ev.waitq.lock);
 283
 284         req->buf      = data;
 285         req->length   = len;
 286
 287         /*
 288          * UDC layer requires to provide a buffer even for ZLP, but should
 289          * not use it at all. Let's provide some poisoned pointer to catch
 290          * possible bug in the driver.
 291          */
 292         if (req->buf == NULL)
 293                 req->buf = (void *)0xDEADBABE;
 294
 295         reinit_completion(&ffs->ep0req_completion);
 296
 297         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 298         if (unlikely(ret < 0))
 299                 return ret;
 300
 301         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 302         if (unlikely(ret)) {
 303                 usb_ep_dequeue(ffs->gadget->ep0, req);
 304                 return -EINTR;
 305         }
 306
 307         ffs->setup_state = FFS_NO_SETUP;
 308         return req->status ? req->status : req->actual;
 309 }
 310
 311 static int __ffs_ep0_stall(struct ffs_data *ffs)
 312 {
 313         if (ffs->ev.can_stall) {
 314                 pr_vdebug("ep0 stall\n");
 315                 usb_ep_set_halt(ffs->gadget->ep0);
 316                 ffs->setup_state = FFS_NO_SETUP;
 317                 return -EL2HLT;
 318         } else {
 319                 pr_debug("bogus ep0 stall!\n");
 320                 return -ESRCH;
 321         }
 322 }
 323
 324 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 325                              size_t len, loff_t *ptr)
 326 {
 327         struct ffs_data *ffs = file->private_data;
 328         ssize_t ret;
 329         char *data;
 330
 331         ENTER();
 332
 333         /* Fast check if setup was canceled */
 334         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 335                 return -EIDRM;
 336
 337         /* Acquire mutex */
 338         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 339         if (unlikely(ret < 0))
 340                 return ret;
 341
 342         /* Check state */
 343         switch (ffs->state) {
 344         case FFS_READ_DESCRIPTORS:
 345         case FFS_READ_STRINGS:
 346                 /* Copy data */
 347                 if (unlikely(len < 16)) {
 348                         ret = -EINVAL;
 349                         break;
 350                 }
 351
 352                 data = ffs_prepare_buffer(buf, len);
 353                 if (IS_ERR(data)) {
 354                         ret = PTR_ERR(data);
 355                         break;
 356                 }
 357
 358                 /* Handle data */
 359                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 360                         pr_info("read descriptors\n");
 361                         ret = __ffs_data_got_descs(ffs, data, len);
 362                         if (unlikely(ret < 0))
 363                                 break;
 364
 365                         ffs->state = FFS_READ_STRINGS;
 366                         ret = len;
 367                 } else {
 368                         pr_info("read strings\n");
 369                         ret = __ffs_data_got_strings(ffs, data, len);
 370                         if (unlikely(ret < 0))
 371                                 break;
 372
 373                         ret = ffs_epfiles_create(ffs);
 374                         if (unlikely(ret)) {
 375                                 ffs->state = FFS_CLOSING;
 376                                 break;
 377                         }
 378
 379                         ffs->state = FFS_ACTIVE;
 380                         mutex_unlock(&ffs->mutex);
 381
 382                         ret = ffs_ready(ffs);
 383                         if (unlikely(ret < 0)) {
 384                                 ffs->state = FFS_CLOSING;
 385                                 return ret;
 386                         }
 387
 388                         return len;
 389                 }
 390                 break;
 391
 392         case FFS_ACTIVE:
 393                 data = NULL;
 394                 /*
 395                  * We're called from user space, we can use _irq
 396                  * rather then _irqsave
 397                  */
 398                 spin_lock_irq(&ffs->ev.waitq.lock);
 399                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 400                 case FFS_SETUP_CANCELLED:
 401                         ret = -EIDRM;
 402                         goto done_spin;
 403
 404                 case FFS_NO_SETUP:
 405                         ret = -ESRCH;
 406                         goto done_spin;
 407
 408                 case FFS_SETUP_PENDING:
 409                         break;
 410                 }
 411
 412                 /* FFS_SETUP_PENDING */
 413                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 414                         spin_unlock_irq(&ffs->ev.waitq.lock);
 415                         ret = __ffs_ep0_stall(ffs);
 416                         break;
 417                 }
 418
 419                 /* FFS_SETUP_PENDING and not stall */
 420                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 421
 422                 spin_unlock_irq(&ffs->ev.waitq.lock);
 423
 424                 data = ffs_prepare_buffer(buf, len);
 425                 if (IS_ERR(data)) {
 426                         ret = PTR_ERR(data);
 427                         break;
 428                 }
 429
 430                 spin_lock_irq(&ffs->ev.waitq.lock);
 431
 432                 /*
 433                  * We are guaranteed to be still in FFS_ACTIVE state
 434                  * but the state of setup could have changed from
 435                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 436                  * to check for that.  If that happened we copied data
 437                  * from user space in vain but it's unlikely.
 438                  *
 439                  * For sure we are not in FFS_NO_SETUP since this is
 440                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 441                  * transition can be performed and it's protected by
 442                  * mutex.
 443                  */
 444                 if (ffs_setup_state_clear_cancelled(ffs) ==
 445                     FFS_SETUP_CANCELLED) {
 446                         ret = -EIDRM;
 447 done_spin:
 448                         spin_unlock_irq(&ffs->ev.waitq.lock);
 449                 } else {
 450                         /* unlocks spinlock */
 451                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 452                 }
 453                 kfree(data);
 454                 break;
 455
 456         default:
 457                 ret = -EBADFD;
 458                 break;
 459         }
 460
 461         mutex_unlock(&ffs->mutex);
 462         return ret;
 463 }
 464
 465 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 466 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 467                                      size_t n)
 468         __releases(&ffs->ev.waitq.lock)
 469 {
 470         /*
 471          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 472          * size of ffs->ev.types array (which is four) so that's how much space
 473          * we reserve.
 474          */
 475         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 476         const size_t size = n * sizeof *events;
 477         unsigned i = 0;
 478
 479         memset(events, 0, size);
 480
 481         do {
 482                 events[i].type = ffs->ev.types[i];
 483                 if (events[i].type == FUNCTIONFS_SETUP) {
 484                         events[i].u.setup = ffs->ev.setup;
 485                         ffs->setup_state = FFS_SETUP_PENDING;
 486                 }
 487         } while (++i < n);
 488
 489         ffs->ev.count -= n;
 490         if (ffs->ev.count)
 491                 memmove(ffs->ev.types, ffs->ev.types + n,
 492                         ffs->ev.count * sizeof *ffs->ev.types);
 493
 494         spin_unlock_irq(&ffs->ev.waitq.lock);
 495         mutex_unlock(&ffs->mutex);
 496
 497         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 498 }
 499
 500 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 501                             size_t len, loff_t *ptr)
 502 {
 503         struct ffs_data *ffs = file->private_data;
 504         char *data = NULL;
 505         size_t n;
 506         int ret;
 507
 508         ENTER();
 509
 510         /* Fast check if setup was canceled */
 511         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 512                 return -EIDRM;
 513
 514         /* Acquire mutex */
 515         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 516         if (unlikely(ret < 0))
 517                 return ret;
 518
 519         /* Check state */
 520         if (ffs->state != FFS_ACTIVE) {
 521                 ret = -EBADFD;
 522                 goto done_mutex;
 523         }
 524
 525         /*
 526          * We're called from user space, we can use _irq rather then
 527          * _irqsave
 528          */
 529         spin_lock_irq(&ffs->ev.waitq.lock);
 530
 531         switch (ffs_setup_state_clear_cancelled(ffs)) {
 532         case FFS_SETUP_CANCELLED:
 533                 ret = -EIDRM;
 534                 break;
 535
 536         case FFS_NO_SETUP:
 537                 n = len / sizeof(struct usb_functionfs_event);
 538                 if (unlikely(!n)) {
 539                         ret = -EINVAL;
 540                         break;
 541                 }
 542
 543                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 544                         ret = -EAGAIN;
 545                         break;
 546                 }
 547
 548                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 549                                                         ffs->ev.count)) {
 550                         ret = -EINTR;
 551                         break;
 552                 }
 553
 554                 /* unlocks spinlock */
 555                 return __ffs_ep0_read_events(ffs, buf,
 556                                              min(n, (size_t)ffs->ev.count));
 557
 558         case FFS_SETUP_PENDING:
 559                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 560                         spin_unlock_irq(&ffs->ev.waitq.lock);
 561                         ret = __ffs_ep0_stall(ffs);
 562                         goto done_mutex;
 563                 }
 564
 565                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 566
 567                 spin_unlock_irq(&ffs->ev.waitq.lock);
 568
 569                 if (likely(len)) {
 570                         data = kmalloc(len, GFP_KERNEL);
 571                         if (unlikely(!data)) {
 572                                 ret = -ENOMEM;
 573                                 goto done_mutex;
 574                         }
 575                 }
 576
 577                 spin_lock_irq(&ffs->ev.waitq.lock);
 578
 579                 /* See ffs_ep0_write() */
 580                 if (ffs_setup_state_clear_cancelled(ffs) ==
 581                     FFS_SETUP_CANCELLED) {
 582                         ret = -EIDRM;
 583                         break;
 584                 }
 585
 586                 /* unlocks spinlock */
 587                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 588                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 589                         ret = -EFAULT;
 590                 goto done_mutex;
 591
 592         default:
 593                 ret = -EBADFD;
 594                 break;
 595         }
 596
 597         spin_unlock_irq(&ffs->ev.waitq.lock);
 598 done_mutex:
 599         mutex_unlock(&ffs->mutex);
 600         kfree(data);
 601         return ret;
 602 }
 603
 604 static int ffs_ep0_open(struct inode *inode, struct file *file)
 605 {
 606         struct ffs_data *ffs = inode->i_private;
 607
 608         ENTER();
 609
 610         if (unlikely(ffs->state == FFS_CLOSING))
 611                 return -EBUSY;
 612
 613         file->private_data = ffs;
 614         ffs_data_opened(ffs);
 615
 616         return 0;
 617 }
 618
 619 static int ffs_ep0_release(struct inode *inode, struct file *file)
 620 {
 621         struct ffs_data *ffs = file->private_data;
 622
 623         ENTER();
 624
 625         ffs_data_closed(ffs);
 626
 627         return 0;
 628 }
 629
 630 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 631 {
 632         struct ffs_data *ffs = file->private_data;
 633         struct usb_gadget *gadget = ffs->gadget;
 634         long ret;
 635
 636         ENTER();
 637
 638         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 639                 struct ffs_function *func = ffs->func;
 640                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 641         } else if (gadget && gadget->ops->ioctl) {
 642                 ret = gadget->ops->ioctl(gadget, code, value);
 643         } else {
 644                 ret = -ENOTTY;
 645         }
 646
 647         return ret;
 648 }
 649
 650 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 651 {
 652         struct ffs_data *ffs = file->private_data;
 653         __poll_t mask = EPOLLWRNORM;
 654         int ret;
 655
 656         poll_wait(file, &ffs->ev.waitq, wait);
 657
 658         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 659         if (unlikely(ret < 0))
 660                 return mask;
 661
 662         switch (ffs->state) {
 663         case FFS_READ_DESCRIPTORS:
 664         case FFS_READ_STRINGS:
 665                 mask |= EPOLLOUT;
 666                 break;
 667
 668         case FFS_ACTIVE:
 669                 switch (ffs->setup_state) {
 670                 case FFS_NO_SETUP:
 671                         if (ffs->ev.count)
 672                                 mask |= EPOLLIN;
 673                         break;
 674
 675                 case FFS_SETUP_PENDING:
 676                 case FFS_SETUP_CANCELLED:
 677                         mask |= (EPOLLIN | EPOLLOUT);
 678                         break;
 679                 }
 680         case FFS_CLOSING:
 681                 break;
 682         case FFS_DEACTIVATED:
 683                 break;
 684         }
 685
 686         mutex_unlock(&ffs->mutex);
 687
 688         return mask;
 689 }
 690
 691 static const struct file_operations ffs_ep0_operations = {
 692         .llseek =       no_llseek,
 693
 694         .open =         ffs_ep0_open,
 695         .write =        ffs_ep0_write,
 696         .read =         ffs_ep0_read,
 697         .release =      ffs_ep0_release,
 698         .unlocked_ioctl =       ffs_ep0_ioctl,
 699         .poll =         ffs_ep0_poll,
 700 };
 701
 702
 703 /* "Normal" endpoints operations ********************************************/
 704
 705 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 706 {
 707         ENTER();
 708         if (likely(req->context)) {
 709                 struct ffs_ep *ep = _ep->driver_data;
 710                 ep->status = req->status ? req->status : req->actual;
 711                 complete(req->context);
 712         }
 713 }
 714
 715 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 716 {
 717         ssize_t ret = copy_to_iter(data, data_len, iter);
 718         if (likely(ret == data_len))
 719                 return ret;
 720
 721         if (unlikely(iov_iter_count(iter)))
 722                 return -EFAULT;
 723
 724         /*
 725          * Dear user space developer!
 726          *
 727          * TL;DR: To stop getting below error message in your kernel log, change
 728          * user space code using functionfs to align read buffers to a max
 729          * packet size.
 730          *
 731          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 732          * packet size.  When unaligned buffer is passed to functionfs, it
 733          * internally uses a larger, aligned buffer so that such UDCs are happy.
 734          *
 735          * Unfortunately, this means that host may send more data than was
 736          * requested in read(2) system call.  f_fs doesn’t know what to do with
 737          * that excess data so it simply drops it.
 738          *
 739          * Was the buffer aligned in the first place, no such problem would
 740          * happen.
 741          *
 742          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 743          * by splitting a request into multiple parts.  This splitting may still
 744          * be a problem though so it’s likely best to align the buffer
 745          * regardless of it being AIO or not..
 746          *
 747          * This only affects OUT endpoints, i.e. reading data with a read(2),
 748          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 749          * affected.
 750          */
 751         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 752                "Align read buffer size to max packet size to avoid the problem.\n",
 753                data_len, ret);
 754
 755         return ret;
 756 }
 757
 758 /*
 759  * allocate a virtually contiguous buffer and create a scatterlist describing it
 760  * @sg_table    - pointer to a place to be filled with sg_table contents
 761  * @size        - required buffer size
 762  */
 763 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 764 {
 765         struct page **pages;
 766         void *vaddr, *ptr;
 767         unsigned int n_pages;
 768         int i;
 769
 770         vaddr = vmalloc(sz);
 771         if (!vaddr)
 772                 return NULL;
 773
 774         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 775         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 776         if (!pages) {
 777                 vfree(vaddr);
 778
 779                 return NULL;
 780         }
 781         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 782                 pages[i] = vmalloc_to_page(ptr);
 783
 784         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 785                 kvfree(pages);
 786                 vfree(vaddr);
 787
 788                 return NULL;
 789         }
 790         kvfree(pages);
 791
 792         return vaddr;
 793 }
 794
 795 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 796         size_t data_len)
 797 {
 798         if (io_data->use_sg)
 799                 return ffs_build_sg_list(&io_data->sgt, data_len);
 800
 801         return kmalloc(data_len, GFP_KERNEL);
 802 }
 803
 804 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 805 {
 806         if (!io_data->buf)
 807                 return;
 808
 809         if (io_data->use_sg) {
 810                 sg_free_table(&io_data->sgt);
 811                 vfree(io_data->buf);
 812         } else {
 813                 kfree(io_data->buf);
 814         }
 815 }
 816
 817 static void ffs_user_copy_worker(struct work_struct *work)
 818 {
 819         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 820                                                    work);
 821         int ret = io_data->req->status ? io_data->req->status :
 822                                          io_data->req->actual;
 823         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 824
 825         if (io_data->read && ret > 0) {
 826                 mm_segment_t oldfs = get_fs();
 827
 828                 set_fs(USER_DS);
 829                 use_mm(io_data->mm);
 830                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 831                 unuse_mm(io_data->mm);
 832                 set_fs(oldfs);
 833         }
 834
 835         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 836
 837         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 838                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 839
 840         usb_ep_free_request(io_data->ep, io_data->req);
 841
 842         if (io_data->read)
 843                 kfree(io_data->to_free);
 844         ffs_free_buffer(io_data);
 845         kfree(io_data);
 846 }
 847
 848 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 849                                          struct usb_request *req)
 850 {
 851         struct ffs_io_data *io_data = req->context;
 852         struct ffs_data *ffs = io_data->ffs;
 853
 854         ENTER();
 855
 856         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 857         queue_work(ffs->io_completion_wq, &io_data->work);
 858 }
 859
 860 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 861 {
 862         /*
 863          * See comment in struct ffs_epfile for full read_buffer pointer
 864          * synchronisation story.
 865          */
 866         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 867         if (buf && buf != READ_BUFFER_DROP)
 868                 kfree(buf);
 869 }
 870
 871 /* Assumes epfile->mutex is held. */
 872 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 873                                           struct iov_iter *iter)
 874 {
 875         /*
 876          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 877          * the buffer while we are using it.  See comment in struct ffs_epfile
 878          * for full read_buffer pointer synchronisation story.
 879          */
 880         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 881         ssize_t ret;
 882         if (!buf || buf == READ_BUFFER_DROP)
 883                 return 0;
 884
 885         ret = copy_to_iter(buf->data, buf->length, iter);
 886         if (buf->length == ret) {
 887                 kfree(buf);
 888                 return ret;
 889         }
 890
 891         if (unlikely(iov_iter_count(iter))) {
 892                 ret = -EFAULT;
 893         } else {
 894                 buf->length -= ret;
 895                 buf->data += ret;
 896         }
 897
 898         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 899                 kfree(buf);
 900
 901         return ret;
 902 }
 903
 904 /* Assumes epfile->mutex is held. */
 905 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 906                                       void *data, int data_len,
 907                                       struct iov_iter *iter)
 908 {
 909         struct ffs_buffer *buf;
 910
 911         ssize_t ret = copy_to_iter(data, data_len, iter);
 912         if (likely(data_len == ret))
 913                 return ret;
 914
 915         if (unlikely(iov_iter_count(iter)))
 916                 return -EFAULT;
 917
 918         /* See ffs_copy_to_iter for more context. */
 919         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 920                 data_len, ret);
 921
 922         data_len -= ret;
 923         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 924         if (!buf)
 925                 return -ENOMEM;
 926         buf->length = data_len;
 927         buf->data = buf->storage;
 928         memcpy(buf->storage, data + ret, data_len);
 929
 930         /*
 931          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 932          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 933          * in struct ffs_epfile for full read_buffer pointer synchronisation
 934          * story.
 935          */
 936         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 937                 kfree(buf);
 938
 939         return ret;
 940 }
 941
 942 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 943 {
 944         struct ffs_epfile *epfile = file->private_data;
 945         struct usb_request *req;
 946         struct ffs_ep *ep;
 947         char *data = NULL;
 948         ssize_t ret, data_len = -EINVAL;
 949         int halt;
 950
 951         /* Are we still active? */
 952         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 953                 return -ENODEV;
 954
 955         /* Wait for endpoint to be enabled */
 956         ep = epfile->ep;
 957         if (!ep) {
 958                 if (file->f_flags & O_NONBLOCK)
 959                         return -EAGAIN;
 960
 961                 ret = wait_event_interruptible(
 962                                 epfile->ffs->wait, (ep = epfile->ep));
 963                 if (ret)
 964                         return -EINTR;
 965         }
 966
 967         /* Do we halt? */
 968         halt = (!io_data->read == !epfile->in);
 969         if (halt && epfile->isoc)
 970                 return -EINVAL;
 971
 972         /* We will be using request and read_buffer */
 973         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 974         if (unlikely(ret))
 975                 goto error;
 976
 977         /* Allocate & copy */
 978         if (!halt) {
 979                 struct usb_gadget *gadget;
 980
 981                 /*
 982                  * Do we have buffered data from previous partial read?  Check
 983                  * that for synchronous case only because we do not have
 984                  * facility to ‘wake up’ a pending asynchronous read and push
 985                  * buffered data to it which we would need to make things behave
 986                  * consistently.
 987                  */
 988                 if (!io_data->aio && io_data->read) {
 989                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 990                         if (ret)
 991                                 goto error_mutex;
 992                 }
 993
 994                 /*
 995                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 996                  * before the waiting completes, so do not assign to 'gadget'
 997                  * earlier
 998                  */
 999                 gadget = epfile->ffs->gadget;
1000
1001                 spin_lock_irq(&epfile->ffs->eps_lock);
1002                 /* In the meantime, endpoint got disabled or changed. */
1003                 if (epfile->ep != ep) {
1004                         ret = -ESHUTDOWN;
1005                         goto error_lock;
1006                 }
1007                 data_len = iov_iter_count(&io_data->data);
1008                 /*
1009                  * Controller may require buffer size to be aligned to
1010                  * maxpacketsize of an out endpoint.
1011                  */
1012                 if (io_data->read)
1013                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1014
1015                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1016                 spin_unlock_irq(&epfile->ffs->eps_lock);
1017
1018                 data = ffs_alloc_buffer(io_data, data_len);
1019                 if (unlikely(!data)) {
1020                         ret = -ENOMEM;
1021                         goto error_mutex;
1022                 }
1023                 if (!io_data->read &&
1024                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1025                         ret = -EFAULT;
1026                         goto error_mutex;
1027                 }
1028         }
1029
1030         spin_lock_irq(&epfile->ffs->eps_lock);
1031
1032         if (epfile->ep != ep) {
1033                 /* In the meantime, endpoint got disabled or changed. */
1034                 ret = -ESHUTDOWN;
1035         } else if (halt) {
1036                 ret = usb_ep_set_halt(ep->ep);
1037                 if (!ret)
1038                         ret = -EBADMSG;
1039         } else if (unlikely(data_len == -EINVAL)) {
1040                 /*
1041                  * Sanity Check: even though data_len can't be used
1042                  * uninitialized at the time I write this comment, some
1043                  * compilers complain about this situation.
1044                  * In order to keep the code clean from warnings, data_len is
1045                  * being initialized to -EINVAL during its declaration, which
1046                  * means we can't rely on compiler anymore to warn no future
1047                  * changes won't result in data_len being used uninitialized.
1048                  * For such reason, we're adding this redundant sanity check
1049                  * here.
1050                  */
1051                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1052                 ret = -EINVAL;
1053         } else if (!io_data->aio) {
1054                 DECLARE_COMPLETION_ONSTACK(done);
1055                 bool interrupted = false;
1056
1057                 req = ep->req;
1058                 if (io_data->use_sg) {
1059                         req->buf = NULL;
1060                         req->sg = io_data->sgt.sgl;
1061                         req->num_sgs = io_data->sgt.nents;
1062                 } else {
1063                         req->buf = data;
1064                 }
1065                 req->length = data_len;
1066
1067                 io_data->buf = data;
1068
1069                 req->context  = &done;
1070                 req->complete = ffs_epfile_io_complete;
1071
1072                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1073                 if (unlikely(ret < 0))
1074                         goto error_lock;
1075
1076                 spin_unlock_irq(&epfile->ffs->eps_lock);
1077
1078                 if (unlikely(wait_for_completion_interruptible(&done))) {
1079                         /*
1080                          * To avoid race condition with ffs_epfile_io_complete,
1081                          * dequeue the request first then check
1082                          * status. usb_ep_dequeue API should guarantee no race
1083                          * condition with req->complete callback.
1084                          */
1085                         usb_ep_dequeue(ep->ep, req);
1086                         wait_for_completion(&done);
1087                         interrupted = ep->status < 0;
1088                 }
1089
1090                 if (interrupted)
1091                         ret = -EINTR;
1092                 else if (io_data->read && ep->status > 0)
1093                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1094                                                      &io_data->data);
1095                 else
1096                         ret = ep->status;
1097                 goto error_mutex;
1098         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1099                 ret = -ENOMEM;
1100         } else {
1101                 if (io_data->use_sg) {
1102                         req->buf = NULL;
1103                         req->sg = io_data->sgt.sgl;
1104                         req->num_sgs = io_data->sgt.nents;
1105                 } else {
1106                         req->buf = data;
1107                 }
1108                 req->length = data_len;
1109
1110                 io_data->buf = data;
1111                 io_data->ep = ep->ep;
1112                 io_data->req = req;
1113                 io_data->ffs = epfile->ffs;
1114
1115                 req->context  = io_data;
1116                 req->complete = ffs_epfile_async_io_complete;
1117
1118                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1119                 if (unlikely(ret)) {
1120                         usb_ep_free_request(ep->ep, req);
1121                         goto error_lock;
1122                 }
1123
1124                 ret = -EIOCBQUEUED;
1125                 /*
1126                  * Do not kfree the buffer in this function.  It will be freed
1127                  * by ffs_user_copy_worker.
1128                  */
1129                 data = NULL;
1130         }
1131
1132 error_lock:
1133         spin_unlock_irq(&epfile->ffs->eps_lock);
1134 error_mutex:
1135         mutex_unlock(&epfile->mutex);
1136 error:
1137         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1138                 ffs_free_buffer(io_data);
1139         return ret;
1140 }
1141
1142 static int
1143 ffs_epfile_open(struct inode *inode, struct file *file)
1144 {
1145         struct ffs_epfile *epfile = inode->i_private;
1146
1147         ENTER();
1148
1149         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1150                 return -ENODEV;
1151
1152         file->private_data = epfile;
1153         ffs_data_opened(epfile->ffs);
1154
1155         return 0;
1156 }
1157
1158 static int ffs_aio_cancel(struct kiocb *kiocb)
1159 {
1160         struct ffs_io_data *io_data = kiocb->private;
1161         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1162         int value;
1163
1164         ENTER();
1165
1166         spin_lock_irq(&epfile->ffs->eps_lock);
1167
1168         if (likely(io_data && io_data->ep && io_data->req))
1169                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1170         else
1171                 value = -EINVAL;
1172
1173         spin_unlock_irq(&epfile->ffs->eps_lock);
1174
1175         return value;
1176 }
1177
1178 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1179 {
1180         struct ffs_io_data io_data, *p = &io_data;
1181         ssize_t res;
1182
1183         ENTER();
1184
1185         if (!is_sync_kiocb(kiocb)) {
1186                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1187                 if (unlikely(!p))
1188                         return -ENOMEM;
1189                 p->aio = true;
1190         } else {
1191                 memset(p, 0, sizeof(*p));
1192                 p->aio = false;
1193         }
1194
1195         p->read = false;
1196         p->kiocb = kiocb;
1197         p->data = *from;
1198         p->mm = current->mm;
1199
1200         kiocb->private = p;
1201
1202         if (p->aio)
1203                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1204
1205         res = ffs_epfile_io(kiocb->ki_filp, p);
1206         if (res == -EIOCBQUEUED)
1207                 return res;
1208         if (p->aio)
1209                 kfree(p);
1210         else
1211                 *from = p->data;
1212         return res;
1213 }
1214
1215 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1216 {
1217         struct ffs_io_data io_data, *p = &io_data;
1218         ssize_t res;
1219
1220         ENTER();
1221
1222         if (!is_sync_kiocb(kiocb)) {
1223                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1224                 if (unlikely(!p))
1225                         return -ENOMEM;
1226                 p->aio = true;
1227         } else {
1228                 memset(p, 0, sizeof(*p));
1229                 p->aio = false;
1230         }
1231
1232         p->read = true;
1233         p->kiocb = kiocb;
1234         if (p->aio) {
1235                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1236                 if (!p->to_free) {
1237                         kfree(p);
1238                         return -ENOMEM;
1239                 }
1240         } else {
1241                 p->data = *to;
1242                 p->to_free = NULL;
1243         }
1244         p->mm = current->mm;
1245
1246         kiocb->private = p;
1247
1248         if (p->aio)
1249                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1250
1251         res = ffs_epfile_io(kiocb->ki_filp, p);
1252         if (res == -EIOCBQUEUED)
1253                 return res;
1254
1255         if (p->aio) {
1256                 kfree(p->to_free);
1257                 kfree(p);
1258         } else {
1259                 *to = p->data;
1260         }
1261         return res;
1262 }
1263
1264 static int
1265 ffs_epfile_release(struct inode *inode, struct file *file)
1266 {
1267         struct ffs_epfile *epfile = inode->i_private;
1268
1269         ENTER();
1270
1271         __ffs_epfile_read_buffer_free(epfile);
1272         ffs_data_closed(epfile->ffs);
1273
1274         return 0;
1275 }
1276
1277 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1278                              unsigned long value)
1279 {
1280         struct ffs_epfile *epfile = file->private_data;
1281         struct ffs_ep *ep;
1282         int ret;
1283
1284         ENTER();
1285
1286         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1287                 return -ENODEV;
1288
1289         /* Wait for endpoint to be enabled */
1290         ep = epfile->ep;
1291         if (!ep) {
1292                 if (file->f_flags & O_NONBLOCK)
1293                         return -EAGAIN;
1294
1295                 ret = wait_event_interruptible(
1296                                 epfile->ffs->wait, (ep = epfile->ep));
1297                 if (ret)
1298                         return -EINTR;
1299         }
1300
1301         spin_lock_irq(&epfile->ffs->eps_lock);
1302
1303         /* In the meantime, endpoint got disabled or changed. */
1304         if (epfile->ep != ep) {
1305                 spin_unlock_irq(&epfile->ffs->eps_lock);
1306                 return -ESHUTDOWN;
1307         }
1308
1309         switch (code) {
1310         case FUNCTIONFS_FIFO_STATUS:
1311                 ret = usb_ep_fifo_status(epfile->ep->ep);
1312                 break;
1313         case FUNCTIONFS_FIFO_FLUSH:
1314                 usb_ep_fifo_flush(epfile->ep->ep);
1315                 ret = 0;
1316                 break;
1317         case FUNCTIONFS_CLEAR_HALT:
1318                 ret = usb_ep_clear_halt(epfile->ep->ep);
1319                 break;
1320         case FUNCTIONFS_ENDPOINT_REVMAP:
1321                 ret = epfile->ep->num;
1322                 break;
1323         case FUNCTIONFS_ENDPOINT_DESC:
1324         {
1325                 int desc_idx;
1326                 struct usb_endpoint_descriptor *desc;
1327
1328                 switch (epfile->ffs->gadget->speed) {
1329                 case USB_SPEED_SUPER:
1330                         desc_idx = 2;
1331                         break;
1332                 case USB_SPEED_HIGH:
1333                         desc_idx = 1;
1334                         break;
1335                 default:
1336                         desc_idx = 0;
1337                 }
1338                 desc = epfile->ep->descs[desc_idx];
1339
1340                 spin_unlock_irq(&epfile->ffs->eps_lock);
1341                 ret = copy_to_user((void __user *)value, desc, desc->bLength);
1342                 if (ret)
1343                         ret = -EFAULT;
1344                 return ret;
1345         }
1346         default:
1347                 ret = -ENOTTY;
1348         }
1349         spin_unlock_irq(&epfile->ffs->eps_lock);
1350
1351         return ret;
1352 }
1353
1354 #ifdef CONFIG_COMPAT
1355 static long ffs_epfile_compat_ioctl(struct file *file, unsigned code,
1356                 unsigned long value)
1357 {
1358         return ffs_epfile_ioctl(file, code, value);
1359 }
1360 #endif
1361
1362 static const struct file_operations ffs_epfile_operations = {
1363         .llseek =       no_llseek,
1364
1365         .open =         ffs_epfile_open,
1366         .write_iter =   ffs_epfile_write_iter,
1367         .read_iter =    ffs_epfile_read_iter,
1368         .release =      ffs_epfile_release,
1369         .unlocked_ioctl =       ffs_epfile_ioctl,
1370 #ifdef CONFIG_COMPAT
1371         .compat_ioctl = ffs_epfile_compat_ioctl,
1372 #endif
1373 };
1374
1375
1376 /* File system and super block operations ***********************************/
1377
1378 /*
1379  * Mounting the file system creates a controller file, used first for
1380  * function configuration then later for event monitoring.
1381  */
1382
1383 static struct inode *__must_check
1384 ffs_sb_make_inode(struct super_block *sb, void *data,
1385                   const struct file_operations *fops,
1386                   const struct inode_operations *iops,
1387                   struct ffs_file_perms *perms)
1388 {
1389         struct inode *inode;
1390
1391         ENTER();
1392
1393         inode = new_inode(sb);
1394
1395         if (likely(inode)) {
1396                 struct timespec64 ts = current_time(inode);
1397
1398                 inode->i_ino     = get_next_ino();
1399                 inode->i_mode    = perms->mode;
1400                 inode->i_uid     = perms->uid;
1401                 inode->i_gid     = perms->gid;
1402                 inode->i_atime   = ts;
1403                 inode->i_mtime   = ts;
1404                 inode->i_ctime   = ts;
1405                 inode->i_private = data;
1406                 if (fops)
1407                         inode->i_fop = fops;
1408                 if (iops)
1409                         inode->i_op  = iops;
1410         }
1411
1412         return inode;
1413 }
1414
1415 /* Create "regular" file */
1416 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1417                                         const char *name, void *data,
1418                                         const struct file_operations *fops)
1419 {
1420         struct ffs_data *ffs = sb->s_fs_info;
1421         struct dentry   *dentry;
1422         struct inode    *inode;
1423
1424         ENTER();
1425
1426         dentry = d_alloc_name(sb->s_root, name);
1427         if (unlikely(!dentry))
1428                 return NULL;
1429
1430         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1431         if (unlikely(!inode)) {
1432                 dput(dentry);
1433                 return NULL;
1434         }
1435
1436         d_add(dentry, inode);
1437         return dentry;
1438 }
1439
1440 /* Super block */
1441 static const struct super_operations ffs_sb_operations = {
1442         .statfs =       simple_statfs,
1443         .drop_inode =   generic_delete_inode,
1444 };
1445
1446 struct ffs_sb_fill_data {
1447         struct ffs_file_perms perms;
1448         umode_t root_mode;
1449         const char *dev_name;
1450         bool no_disconnect;
1451         struct ffs_data *ffs_data;
1452 };
1453
1454 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1455 {
1456         struct ffs_sb_fill_data *data = _data;
1457         struct inode    *inode;
1458         struct ffs_data *ffs = data->ffs_data;
1459
1460         ENTER();
1461
1462         ffs->sb              = sb;
1463         data->ffs_data       = NULL;
1464         sb->s_fs_info        = ffs;
1465         sb->s_blocksize      = PAGE_SIZE;
1466         sb->s_blocksize_bits = PAGE_SHIFT;
1467         sb->s_magic          = FUNCTIONFS_MAGIC;
1468         sb->s_op             = &ffs_sb_operations;
1469         sb->s_time_gran      = 1;
1470
1471         /* Root inode */
1472         data->perms.mode = data->root_mode;
1473         inode = ffs_sb_make_inode(sb, NULL,
1474                                   &simple_dir_operations,
1475                                   &simple_dir_inode_operations,
1476                                   &data->perms);
1477         sb->s_root = d_make_root(inode);
1478         if (unlikely(!sb->s_root))
1479                 return -ENOMEM;
1480
1481         /* EP0 file */
1482         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1483                                          &ffs_ep0_operations)))
1484                 return -ENOMEM;
1485
1486         return 0;
1487 }
1488
1489 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1490 {
1491         ENTER();
1492
1493         if (!opts || !*opts)
1494                 return 0;
1495
1496         for (;;) {
1497                 unsigned long value;
1498                 char *eq, *comma;
1499
1500                 /* Option limit */
1501                 comma = strchr(opts, ',');
1502                 if (comma)
1503                         *comma = 0;
1504
1505                 /* Value limit */
1506                 eq = strchr(opts, '=');
1507                 if (unlikely(!eq)) {
1508                         pr_err("'=' missing in %s\n", opts);
1509                         return -EINVAL;
1510                 }
1511                 *eq = 0;
1512
1513                 /* Parse value */
1514                 if (kstrtoul(eq + 1, 0, &value)) {
1515                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1516                         return -EINVAL;
1517                 }
1518
1519                 /* Interpret option */
1520                 switch (eq - opts) {
1521                 case 13:
1522                         if (!memcmp(opts, "no_disconnect", 13))
1523                                 data->no_disconnect = !!value;
1524                         else
1525                                 goto invalid;
1526                         break;
1527                 case 5:
1528                         if (!memcmp(opts, "rmode", 5))
1529                                 data->root_mode  = (value & 0555) | S_IFDIR;
1530                         else if (!memcmp(opts, "fmode", 5))
1531                                 data->perms.mode = (value & 0666) | S_IFREG;
1532                         else
1533                                 goto invalid;
1534                         break;
1535
1536                 case 4:
1537                         if (!memcmp(opts, "mode", 4)) {
1538                                 data->root_mode  = (value & 0555) | S_IFDIR;
1539                                 data->perms.mode = (value & 0666) | S_IFREG;
1540                         } else {
1541                                 goto invalid;
1542                         }
1543                         break;
1544
1545                 case 3:
1546                         if (!memcmp(opts, "uid", 3)) {
1547                                 data->perms.uid = make_kuid(current_user_ns(), value);
1548                                 if (!uid_valid(data->perms.uid)) {
1549                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1550                                         return -EINVAL;
1551                                 }
1552                         } else if (!memcmp(opts, "gid", 3)) {
1553                                 data->perms.gid = make_kgid(current_user_ns(), value);
1554                                 if (!gid_valid(data->perms.gid)) {
1555                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1556                                         return -EINVAL;
1557                                 }
1558                         } else {
1559                                 goto invalid;
1560                         }
1561                         break;
1562
1563                 default:
1564 invalid:
1565                         pr_err("%s: invalid option\n", opts);
1566                         return -EINVAL;
1567                 }
1568
1569                 /* Next iteration */
1570                 if (!comma)
1571                         break;
1572                 opts = comma + 1;
1573         }
1574
1575         return 0;
1576 }
1577
1578 /* "mount -t functionfs dev_name /dev/function" ends up here */
1579
1580 static struct dentry *
1581 ffs_fs_mount(struct file_system_type *t, int flags,
1582               const char *dev_name, void *opts)
1583 {
1584         struct ffs_sb_fill_data data = {
1585                 .perms = {
1586                         .mode = S_IFREG | 0600,
1587                         .uid = GLOBAL_ROOT_UID,
1588                         .gid = GLOBAL_ROOT_GID,
1589                 },
1590                 .root_mode = S_IFDIR | 0500,
1591                 .no_disconnect = false,
1592         };
1593         struct dentry *rv;
1594         int ret;
1595         void *ffs_dev;
1596         struct ffs_data *ffs;
1597
1598         ENTER();
1599
1600         ret = ffs_fs_parse_opts(&data, opts);
1601         if (unlikely(ret < 0))
1602                 return ERR_PTR(ret);
1603
1604         ffs = ffs_data_new(dev_name);
1605         if (unlikely(!ffs))
1606                 return ERR_PTR(-ENOMEM);
1607         ffs->file_perms = data.perms;
1608         ffs->no_disconnect = data.no_disconnect;
1609
1610         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1611         if (unlikely(!ffs->dev_name)) {
1612                 ffs_data_put(ffs);
1613                 return ERR_PTR(-ENOMEM);
1614         }
1615
1616         ffs_dev = ffs_acquire_dev(dev_name);
1617         if (IS_ERR(ffs_dev)) {
1618                 ffs_data_put(ffs);
1619                 return ERR_CAST(ffs_dev);
1620         }
1621         ffs->private_data = ffs_dev;
1622         data.ffs_data = ffs;
1623
1624         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1625         if (IS_ERR(rv) && data.ffs_data) {
1626                 ffs_release_dev(data.ffs_data);
1627                 ffs_data_put(data.ffs_data);
1628         }
1629         return rv;
1630 }
1631
1632 static void
1633 ffs_fs_kill_sb(struct super_block *sb)
1634 {
1635         ENTER();
1636
1637         kill_litter_super(sb);
1638         if (sb->s_fs_info) {
1639                 ffs_release_dev(sb->s_fs_info);
1640                 ffs_data_closed(sb->s_fs_info);
1641         }
1642 }
1643
1644 static struct file_system_type ffs_fs_type = {
1645         .owner          = THIS_MODULE,
1646         .name           = "functionfs",
1647         .mount          = ffs_fs_mount,
1648         .kill_sb        = ffs_fs_kill_sb,
1649 };
1650 MODULE_ALIAS_FS("functionfs");
1651
1652
1653 /* Driver's main init/cleanup functions *************************************/
1654
1655 static int functionfs_init(void)
1656 {
1657         int ret;
1658
1659         ENTER();
1660
1661         ret = register_filesystem(&ffs_fs_type);
1662         if (likely(!ret))
1663                 pr_info("file system registered\n");
1664         else
1665                 pr_err("failed registering file system (%d)\n", ret);
1666
1667         return ret;
1668 }
1669
1670 static void functionfs_cleanup(void)
1671 {
1672         ENTER();
1673
1674         pr_info("unloading\n");
1675         unregister_filesystem(&ffs_fs_type);
1676 }
1677
1678
1679 /* ffs_data and ffs_function construction and destruction code **************/
1680
1681 static void ffs_data_clear(struct ffs_data *ffs);
1682 static void ffs_data_reset(struct ffs_data *ffs);
1683
1684 static void ffs_data_get(struct ffs_data *ffs)
1685 {
1686         ENTER();
1687
1688         refcount_inc(&ffs->ref);
1689 }
1690
1691 static void ffs_data_opened(struct ffs_data *ffs)
1692 {
1693         ENTER();
1694
1695         refcount_inc(&ffs->ref);
1696         if (atomic_add_return(1, &ffs->opened) == 1 &&
1697                         ffs->state == FFS_DEACTIVATED) {
1698                 ffs->state = FFS_CLOSING;
1699                 ffs_data_reset(ffs);
1700         }
1701 }
1702
1703 static void ffs_data_put(struct ffs_data *ffs)
1704 {
1705         ENTER();
1706
1707         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1708                 pr_info("%s(): freeing\n", __func__);
1709                 ffs_data_clear(ffs);
1710                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1711                        waitqueue_active(&ffs->ep0req_completion.wait) ||
1712                        waitqueue_active(&ffs->wait));
1713                 destroy_workqueue(ffs->io_completion_wq);
1714                 kfree(ffs->dev_name);
1715                 kfree(ffs);
1716         }
1717 }
1718
1719 static void ffs_data_closed(struct ffs_data *ffs)
1720 {
1721         ENTER();
1722
1723         if (atomic_dec_and_test(&ffs->opened)) {
1724                 if (ffs->no_disconnect) {
1725                         ffs->state = FFS_DEACTIVATED;
1726                         if (ffs->epfiles) {
1727                                 ffs_epfiles_destroy(ffs->epfiles,
1728                                                    ffs->eps_count);
1729                                 ffs->epfiles = NULL;
1730                         }
1731                         if (ffs->setup_state == FFS_SETUP_PENDING)
1732                                 __ffs_ep0_stall(ffs);
1733                 } else {
1734                         ffs->state = FFS_CLOSING;
1735                         ffs_data_reset(ffs);
1736                 }
1737         }
1738         if (atomic_read(&ffs->opened) < 0) {
1739                 ffs->state = FFS_CLOSING;
1740                 ffs_data_reset(ffs);
1741         }
1742
1743         ffs_data_put(ffs);
1744 }
1745
1746 static struct ffs_data *ffs_data_new(const char *dev_name)
1747 {
1748         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1749         if (unlikely(!ffs))
1750                 return NULL;
1751
1752         ENTER();
1753
1754         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1755         if (!ffs->io_completion_wq) {
1756                 kfree(ffs);
1757                 return NULL;
1758         }
1759
1760         refcount_set(&ffs->ref, 1);
1761         atomic_set(&ffs->opened, 0);
1762         ffs->state = FFS_READ_DESCRIPTORS;
1763         mutex_init(&ffs->mutex);
1764         spin_lock_init(&ffs->eps_lock);
1765         init_waitqueue_head(&ffs->ev.waitq);
1766         init_waitqueue_head(&ffs->wait);
1767         init_completion(&ffs->ep0req_completion);
1768
1769         /* XXX REVISIT need to update it in some places, or do we? */
1770         ffs->ev.can_stall = 1;
1771
1772         return ffs;
1773 }
1774
1775 static void ffs_data_clear(struct ffs_data *ffs)
1776 {
1777         ENTER();
1778
1779         ffs_closed(ffs);
1780
1781         BUG_ON(ffs->gadget);
1782
1783         if (ffs->epfiles)
1784                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1785
1786         if (ffs->ffs_eventfd)
1787                 eventfd_ctx_put(ffs->ffs_eventfd);
1788
1789         kfree(ffs->raw_descs_data);
1790         kfree(ffs->raw_strings);
1791         kfree(ffs->stringtabs);
1792 }
1793
1794 static void ffs_data_reset(struct ffs_data *ffs)
1795 {
1796         ENTER();
1797
1798         ffs_data_clear(ffs);
1799
1800         ffs->epfiles = NULL;
1801         ffs->raw_descs_data = NULL;
1802         ffs->raw_descs = NULL;
1803         ffs->raw_strings = NULL;
1804         ffs->stringtabs = NULL;
1805
1806         ffs->raw_descs_length = 0;
1807         ffs->fs_descs_count = 0;
1808         ffs->hs_descs_count = 0;
1809         ffs->ss_descs_count = 0;
1810
1811         ffs->strings_count = 0;
1812         ffs->interfaces_count = 0;
1813         ffs->eps_count = 0;
1814
1815         ffs->ev.count = 0;
1816
1817         ffs->state = FFS_READ_DESCRIPTORS;
1818         ffs->setup_state = FFS_NO_SETUP;
1819         ffs->flags = 0;
1820 }
1821
1822
1823 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1824 {
1825         struct usb_gadget_strings **lang;
1826         int first_id;
1827
1828         ENTER();
1829
1830         if (WARN_ON(ffs->state != FFS_ACTIVE
1831                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1832                 return -EBADFD;
1833
1834         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1835         if (unlikely(first_id < 0))
1836                 return first_id;
1837
1838         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1839         if (unlikely(!ffs->ep0req))
1840                 return -ENOMEM;
1841         ffs->ep0req->complete = ffs_ep0_complete;
1842         ffs->ep0req->context = ffs;
1843
1844         lang = ffs->stringtabs;
1845         if (lang) {
1846                 for (; *lang; ++lang) {
1847                         struct usb_string *str = (*lang)->strings;
1848                         int id = first_id;
1849                         for (; str->s; ++id, ++str)
1850                                 str->id = id;
1851                 }
1852         }
1853
1854         ffs->gadget = cdev->gadget;
1855         ffs_data_get(ffs);
1856         return 0;
1857 }
1858
1859 static void functionfs_unbind(struct ffs_data *ffs)
1860 {
1861         ENTER();
1862
1863         if (!WARN_ON(!ffs->gadget)) {
1864                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1865                 ffs->ep0req = NULL;
1866                 ffs->gadget = NULL;
1867                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1868                 ffs_data_put(ffs);
1869         }
1870 }
1871
1872 static int ffs_epfiles_create(struct ffs_data *ffs)
1873 {
1874         struct ffs_epfile *epfile, *epfiles;
1875         unsigned i, count;
1876
1877         ENTER();
1878
1879         count = ffs->eps_count;
1880         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1881         if (!epfiles)
1882                 return -ENOMEM;
1883
1884         epfile = epfiles;
1885         for (i = 1; i <= count; ++i, ++epfile) {
1886                 epfile->ffs = ffs;
1887                 mutex_init(&epfile->mutex);
1888                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1889                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1890                 else
1891                         sprintf(epfile->name, "ep%u", i);
1892                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1893                                                  epfile,
1894                                                  &ffs_epfile_operations);
1895                 if (unlikely(!epfile->dentry)) {
1896                         ffs_epfiles_destroy(epfiles, i - 1);
1897                         return -ENOMEM;
1898                 }
1899         }
1900
1901         ffs->epfiles = epfiles;
1902         return 0;
1903 }
1904
1905 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1906 {
1907         struct ffs_epfile *epfile = epfiles;
1908
1909         ENTER();
1910
1911         for (; count; --count, ++epfile) {
1912                 BUG_ON(mutex_is_locked(&epfile->mutex));
1913                 if (epfile->dentry) {
1914                         d_delete(epfile->dentry);
1915                         dput(epfile->dentry);
1916                         epfile->dentry = NULL;
1917                 }
1918         }
1919
1920         kfree(epfiles);
1921 }
1922
1923 static void ffs_func_eps_disable(struct ffs_function *func)
1924 {
1925         struct ffs_ep *ep         = func->eps;
1926         struct ffs_epfile *epfile = func->ffs->epfiles;
1927         unsigned count            = func->ffs->eps_count;
1928         unsigned long flags;
1929
1930         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1931         while (count--) {
1932                 /* pending requests get nuked */
1933                 if (likely(ep->ep))
1934                         usb_ep_disable(ep->ep);
1935                 ++ep;
1936
1937                 if (epfile) {
1938                         epfile->ep = NULL;
1939                         __ffs_epfile_read_buffer_free(epfile);
1940                         ++epfile;
1941                 }
1942         }
1943         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1944 }
1945
1946 static int ffs_func_eps_enable(struct ffs_function *func)
1947 {
1948         struct ffs_data *ffs      = func->ffs;
1949         struct ffs_ep *ep         = func->eps;
1950         struct ffs_epfile *epfile = ffs->epfiles;
1951         unsigned count            = ffs->eps_count;
1952         unsigned long flags;
1953         int ret = 0;
1954
1955         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1956         while(count--) {
1957                 ep->ep->driver_data = ep;
1958
1959                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1960                 if (ret) {
1961                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1962                                         __func__, ep->ep->name, ret);
1963                         break;
1964                 }
1965
1966                 ret = usb_ep_enable(ep->ep);
1967                 if (likely(!ret)) {
1968                         epfile->ep = ep;
1969                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1970                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1971                 } else {
1972                         break;
1973                 }
1974
1975                 ++ep;
1976                 ++epfile;
1977         }
1978
1979         wake_up_interruptible(&ffs->wait);
1980         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1981
1982         return ret;
1983 }
1984
1985
1986 /* Parsing and building descriptors and strings *****************************/
1987
1988 /*
1989  * This validates if data pointed by data is a valid USB descriptor as
1990  * well as record how many interfaces, endpoints and strings are
1991  * required by given configuration.  Returns address after the
1992  * descriptor or NULL if data is invalid.
1993  */
1994
1995 enum ffs_entity_type {
1996         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1997 };
1998
1999 enum ffs_os_desc_type {
2000         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
2001 };
2002
2003 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2004                                    u8 *valuep,
2005                                    struct usb_descriptor_header *desc,
2006                                    void *priv);
2007
2008 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2009                                     struct usb_os_desc_header *h, void *data,
2010                                     unsigned len, void *priv);
2011
2012 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2013                                            ffs_entity_callback entity,
2014                                            void *priv, int *current_class)
2015 {
2016         struct usb_descriptor_header *_ds = (void *)data;
2017         u8 length;
2018         int ret;
2019
2020         ENTER();
2021
2022         /* At least two bytes are required: length and type */
2023         if (len < 2) {
2024                 pr_vdebug("descriptor too short\n");
2025                 return -EINVAL;
2026         }
2027
2028         /* If we have at least as many bytes as the descriptor takes? */
2029         length = _ds->bLength;
2030         if (len < length) {
2031                 pr_vdebug("descriptor longer then available data\n");
2032                 return -EINVAL;
2033         }
2034
2035 #define __entity_check_INTERFACE(val)  1
2036 #define __entity_check_STRING(val)     (val)
2037 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2038 #define __entity(type, val) do {                                        \
2039                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2040                 if (unlikely(!__entity_check_ ##type(val))) {           \
2041                         pr_vdebug("invalid entity's value\n");          \
2042                         return -EINVAL;                                 \
2043                 }                                                       \
2044                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2045                 if (unlikely(ret < 0)) {                                \
2046                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2047                                  (val), ret);                           \
2048                         return ret;                                     \
2049                 }                                                       \
2050         } while (0)
2051
2052         /* Parse descriptor depending on type. */
2053         switch (_ds->bDescriptorType) {
2054         case USB_DT_DEVICE:
2055         case USB_DT_CONFIG:
2056         case USB_DT_STRING:
2057         case USB_DT_DEVICE_QUALIFIER:
2058                 /* function can't have any of those */
2059                 pr_vdebug("descriptor reserved for gadget: %d\n",
2060                       _ds->bDescriptorType);
2061                 return -EINVAL;
2062
2063         case USB_DT_INTERFACE: {
2064                 struct usb_interface_descriptor *ds = (void *)_ds;
2065                 pr_vdebug("interface descriptor\n");
2066                 if (length != sizeof *ds)
2067                         goto inv_length;
2068
2069                 __entity(INTERFACE, ds->bInterfaceNumber);
2070                 if (ds->iInterface)
2071                         __entity(STRING, ds->iInterface);
2072                 *current_class = ds->bInterfaceClass;
2073         }
2074                 break;
2075
2076         case USB_DT_ENDPOINT: {
2077                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2078                 pr_vdebug("endpoint descriptor\n");
2079                 if (length != USB_DT_ENDPOINT_SIZE &&
2080                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2081                         goto inv_length;
2082                 __entity(ENDPOINT, ds->bEndpointAddress);
2083         }
2084                 break;
2085
2086         case USB_TYPE_CLASS | 0x01:
2087                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2088                         pr_vdebug("hid descriptor\n");
2089                         if (length != sizeof(struct hid_descriptor))
2090                                 goto inv_length;
2091                         break;
2092                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2093                         pr_vdebug("ccid descriptor\n");
2094                         if (length != sizeof(struct ccid_descriptor))
2095                                 goto inv_length;
2096                         break;
2097                 } else {
2098                         pr_vdebug("unknown descriptor: %d for class %d\n",
2099                               _ds->bDescriptorType, *current_class);
2100                         return -EINVAL;
2101                 }
2102
2103         case USB_DT_OTG:
2104                 if (length != sizeof(struct usb_otg_descriptor))
2105                         goto inv_length;
2106                 break;
2107
2108         case USB_DT_INTERFACE_ASSOCIATION: {
2109                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2110                 pr_vdebug("interface association descriptor\n");
2111                 if (length != sizeof *ds)
2112                         goto inv_length;
2113                 if (ds->iFunction)
2114                         __entity(STRING, ds->iFunction);
2115         }
2116                 break;
2117
2118         case USB_DT_SS_ENDPOINT_COMP:
2119                 pr_vdebug("EP SS companion descriptor\n");
2120                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2121                         goto inv_length;
2122                 break;
2123
2124         case USB_DT_OTHER_SPEED_CONFIG:
2125         case USB_DT_INTERFACE_POWER:
2126         case USB_DT_DEBUG:
2127         case USB_DT_SECURITY:
2128         case USB_DT_CS_RADIO_CONTROL:
2129                 /* TODO */
2130                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2131                 return -EINVAL;
2132
2133         default:
2134                 /* We should never be here */
2135                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2136                 return -EINVAL;
2137
2138 inv_length:
2139                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2140                           _ds->bLength, _ds->bDescriptorType);
2141                 return -EINVAL;
2142         }
2143
2144 #undef __entity
2145 #undef __entity_check_DESCRIPTOR
2146 #undef __entity_check_INTERFACE
2147 #undef __entity_check_STRING
2148 #undef __entity_check_ENDPOINT
2149
2150         return length;
2151 }
2152
2153 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2154                                      ffs_entity_callback entity, void *priv)
2155 {
2156         const unsigned _len = len;
2157         unsigned long num = 0;
2158         int current_class = -1;
2159
2160         ENTER();
2161
2162         for (;;) {
2163                 int ret;
2164
2165                 if (num == count)
2166                         data = NULL;
2167
2168                 /* Record "descriptor" entity */
2169                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2170                 if (unlikely(ret < 0)) {
2171                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2172                                  num, ret);
2173                         return ret;
2174                 }
2175
2176                 if (!data)
2177                         return _len - len;
2178
2179                 ret = ffs_do_single_desc(data, len, entity, priv,
2180                         &current_class);
2181                 if (unlikely(ret < 0)) {
2182                         pr_debug("%s returns %d\n", __func__, ret);
2183                         return ret;
2184                 }
2185
2186                 len -= ret;
2187                 data += ret;
2188                 ++num;
2189         }
2190 }
2191
2192 static int __ffs_data_do_entity(enum ffs_entity_type type,
2193                                 u8 *valuep, struct usb_descriptor_header *desc,
2194                                 void *priv)
2195 {
2196         struct ffs_desc_helper *helper = priv;
2197         struct usb_endpoint_descriptor *d;
2198
2199         ENTER();
2200
2201         switch (type) {
2202         case FFS_DESCRIPTOR:
2203                 break;
2204
2205         case FFS_INTERFACE:
2206                 /*
2207                  * Interfaces are indexed from zero so if we
2208                  * encountered interface "n" then there are at least
2209                  * "n+1" interfaces.
2210                  */
2211                 if (*valuep >= helper->interfaces_count)
2212                         helper->interfaces_count = *valuep + 1;
2213                 break;
2214
2215         case FFS_STRING:
2216                 /*
2217                  * Strings are indexed from 1 (0 is reserved
2218                  * for languages list)
2219                  */
2220                 if (*valuep > helper->ffs->strings_count)
2221                         helper->ffs->strings_count = *valuep;
2222                 break;
2223
2224         case FFS_ENDPOINT:
2225                 d = (void *)desc;
2226                 helper->eps_count++;
2227                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2228                         return -EINVAL;
2229                 /* Check if descriptors for any speed were already parsed */
2230                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2231                         helper->ffs->eps_addrmap[helper->eps_count] =
2232                                 d->bEndpointAddress;
2233                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2234                                 d->bEndpointAddress)
2235                         return -EINVAL;
2236                 break;
2237         }
2238
2239         return 0;
2240 }
2241
2242 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2243                                    struct usb_os_desc_header *desc)
2244 {
2245         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2246         u16 w_index = le16_to_cpu(desc->wIndex);
2247
2248         if (bcd_version != 1) {
2249                 pr_vdebug("unsupported os descriptors version: %d",
2250                           bcd_version);
2251                 return -EINVAL;
2252         }
2253         switch (w_index) {
2254         case 0x4:
2255                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2256                 break;
2257         case 0x5:
2258                 *next_type = FFS_OS_DESC_EXT_PROP;
2259                 break;
2260         default:
2261                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2262                 return -EINVAL;
2263         }
2264
2265         return sizeof(*desc);
2266 }
2267
2268 /*
2269  * Process all extended compatibility/extended property descriptors
2270  * of a feature descriptor
2271  */
2272 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2273                                               enum ffs_os_desc_type type,
2274                                               u16 feature_count,
2275                                               ffs_os_desc_callback entity,
2276                                               void *priv,
2277                                               struct usb_os_desc_header *h)
2278 {
2279         int ret;
2280         const unsigned _len = len;
2281
2282         ENTER();
2283
2284         /* loop over all ext compat/ext prop descriptors */
2285         while (feature_count--) {
2286                 ret = entity(type, h, data, len, priv);
2287                 if (unlikely(ret < 0)) {
2288                         pr_debug("bad OS descriptor, type: %d\n", type);
2289                         return ret;
2290                 }
2291                 data += ret;
2292                 len -= ret;
2293         }
2294         return _len - len;
2295 }
2296
2297 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2298 static int __must_check ffs_do_os_descs(unsigned count,
2299                                         char *data, unsigned len,
2300                                         ffs_os_desc_callback entity, void *priv)
2301 {
2302         const unsigned _len = len;
2303         unsigned long num = 0;
2304
2305         ENTER();
2306
2307         for (num = 0; num < count; ++num) {
2308                 int ret;
2309                 enum ffs_os_desc_type type;
2310                 u16 feature_count;
2311                 struct usb_os_desc_header *desc = (void *)data;
2312
2313                 if (len < sizeof(*desc))
2314                         return -EINVAL;
2315
2316                 /*
2317                  * Record "descriptor" entity.
2318                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2319                  * Move the data pointer to the beginning of extended
2320                  * compatibilities proper or extended properties proper
2321                  * portions of the data
2322                  */
2323                 if (le32_to_cpu(desc->dwLength) > len)
2324                         return -EINVAL;
2325
2326                 ret = __ffs_do_os_desc_header(&type, desc);
2327                 if (unlikely(ret < 0)) {
2328                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2329                                  num, ret);
2330                         return ret;
2331                 }
2332                 /*
2333                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2334                  */
2335                 feature_count = le16_to_cpu(desc->wCount);
2336                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2337                     (feature_count > 255 || desc->Reserved))
2338                                 return -EINVAL;
2339                 len -= ret;
2340                 data += ret;
2341
2342                 /*
2343                  * Process all function/property descriptors
2344                  * of this Feature Descriptor
2345                  */
2346                 ret = ffs_do_single_os_desc(data, len, type,
2347                                             feature_count, entity, priv, desc);
2348                 if (unlikely(ret < 0)) {
2349                         pr_debug("%s returns %d\n", __func__, ret);
2350                         return ret;
2351                 }
2352
2353                 len -= ret;
2354                 data += ret;
2355         }
2356         return _len - len;
2357 }
2358
2359 /**
2360  * Validate contents of the buffer from userspace related to OS descriptors.
2361  */
2362 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2363                                  struct usb_os_desc_header *h, void *data,
2364                                  unsigned len, void *priv)
2365 {
2366         struct ffs_data *ffs = priv;
2367         u8 length;
2368
2369         ENTER();
2370
2371         switch (type) {
2372         case FFS_OS_DESC_EXT_COMPAT: {
2373                 struct usb_ext_compat_desc *d = data;
2374                 int i;
2375
2376                 if (len < sizeof(*d) ||
2377                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2378                         return -EINVAL;
2379                 if (d->Reserved1 != 1) {
2380                         /*
2381                          * According to the spec, Reserved1 must be set to 1
2382                          * but older kernels incorrectly rejected non-zero
2383                          * values.  We fix it here to avoid returning EINVAL
2384                          * in response to values we used to accept.
2385                          */
2386                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2387                         d->Reserved1 = 1;
2388                 }
2389                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2390                         if (d->Reserved2[i])
2391                                 return -EINVAL;
2392
2393                 length = sizeof(struct usb_ext_compat_desc);
2394         }
2395                 break;
2396         case FFS_OS_DESC_EXT_PROP: {
2397                 struct usb_ext_prop_desc *d = data;
2398                 u32 type, pdl;
2399                 u16 pnl;
2400
2401                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2402                         return -EINVAL;
2403                 length = le32_to_cpu(d->dwSize);
2404                 if (len < length)
2405                         return -EINVAL;
2406                 type = le32_to_cpu(d->dwPropertyDataType);
2407                 if (type < USB_EXT_PROP_UNICODE ||
2408                     type > USB_EXT_PROP_UNICODE_MULTI) {
2409                         pr_vdebug("unsupported os descriptor property type: %d",
2410                                   type);
2411                         return -EINVAL;
2412                 }
2413                 pnl = le16_to_cpu(d->wPropertyNameLength);
2414                 if (length < 14 + pnl) {
2415                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2416                                   length, pnl, type);
2417                         return -EINVAL;
2418                 }
2419                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2420                 if (length != 14 + pnl + pdl) {
2421                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2422                                   length, pnl, pdl, type);
2423                         return -EINVAL;
2424                 }
2425                 ++ffs->ms_os_descs_ext_prop_count;
2426                 /* property name reported to the host as "WCHAR"s */
2427                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2428                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2429         }
2430                 break;
2431         default:
2432                 pr_vdebug("unknown descriptor: %d\n", type);
2433                 return -EINVAL;
2434         }
2435         return length;
2436 }
2437
2438 static int __ffs_data_got_descs(struct ffs_data *ffs,
2439                                 char *const _data, size_t len)
2440 {
2441         char *data = _data, *raw_descs;
2442         unsigned os_descs_count = 0, counts[3], flags;
2443         int ret = -EINVAL, i;
2444         struct ffs_desc_helper helper;
2445
2446         ENTER();
2447
2448         if (get_unaligned_le32(data + 4) != len)
2449                 goto error;
2450
2451         switch (get_unaligned_le32(data)) {
2452         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2453                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2454                 data += 8;
2455                 len  -= 8;
2456                 break;
2457         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2458                 flags = get_unaligned_le32(data + 8);
2459                 ffs->user_flags = flags;
2460                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2461                               FUNCTIONFS_HAS_HS_DESC |
2462                               FUNCTIONFS_HAS_SS_DESC |
2463                               FUNCTIONFS_HAS_MS_OS_DESC |
2464                               FUNCTIONFS_VIRTUAL_ADDR |
2465                               FUNCTIONFS_EVENTFD |
2466                               FUNCTIONFS_ALL_CTRL_RECIP |
2467                               FUNCTIONFS_CONFIG0_SETUP)) {
2468                         ret = -ENOSYS;
2469                         goto error;
2470                 }
2471                 data += 12;
2472                 len  -= 12;
2473                 break;
2474         default:
2475                 goto error;
2476         }
2477
2478         if (flags & FUNCTIONFS_EVENTFD) {
2479                 if (len < 4)
2480                         goto error;
2481                 ffs->ffs_eventfd =
2482                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2483                 if (IS_ERR(ffs->ffs_eventfd)) {
2484                         ret = PTR_ERR(ffs->ffs_eventfd);
2485                         ffs->ffs_eventfd = NULL;
2486                         goto error;
2487                 }
2488                 data += 4;
2489                 len  -= 4;
2490         }
2491
2492         /* Read fs_count, hs_count and ss_count (if present) */
2493         for (i = 0; i < 3; ++i) {
2494                 if (!(flags & (1 << i))) {
2495                         counts[i] = 0;
2496                 } else if (len < 4) {
2497                         goto error;
2498                 } else {
2499                         counts[i] = get_unaligned_le32(data);
2500                         data += 4;
2501                         len  -= 4;
2502                 }
2503         }
2504         if (flags & (1 << i)) {
2505                 if (len < 4) {
2506                         goto error;
2507                 }
2508                 os_descs_count = get_unaligned_le32(data);
2509                 data += 4;
2510                 len -= 4;
2511         };
2512
2513         /* Read descriptors */
2514         raw_descs = data;
2515         helper.ffs = ffs;
2516         for (i = 0; i < 3; ++i) {
2517                 if (!counts[i])
2518                         continue;
2519                 helper.interfaces_count = 0;
2520                 helper.eps_count = 0;
2521                 ret = ffs_do_descs(counts[i], data, len,
2522                                    __ffs_data_do_entity, &helper);
2523                 if (ret < 0)
2524                         goto error;
2525                 if (!ffs->eps_count && !ffs->interfaces_count) {
2526                         ffs->eps_count = helper.eps_count;
2527                         ffs->interfaces_count = helper.interfaces_count;
2528                 } else {
2529                         if (ffs->eps_count != helper.eps_count) {
2530                                 ret = -EINVAL;
2531                                 goto error;
2532                         }
2533                         if (ffs->interfaces_count != helper.interfaces_count) {
2534                                 ret = -EINVAL;
2535                                 goto error;
2536                         }
2537                 }
2538                 data += ret;
2539                 len  -= ret;
2540         }
2541         if (os_descs_count) {
2542                 ret = ffs_do_os_descs(os_descs_count, data, len,
2543                                       __ffs_data_do_os_desc, ffs);
2544                 if (ret < 0)
2545                         goto error;
2546                 data += ret;
2547                 len -= ret;
2548         }
2549
2550         if (raw_descs == data || len) {
2551                 ret = -EINVAL;
2552                 goto error;
2553         }
2554
2555         ffs->raw_descs_data     = _data;
2556         ffs->raw_descs          = raw_descs;
2557         ffs->raw_descs_length   = data - raw_descs;
2558         ffs->fs_descs_count     = counts[0];
2559         ffs->hs_descs_count     = counts[1];
2560         ffs->ss_descs_count     = counts[2];
2561         ffs->ms_os_descs_count  = os_descs_count;
2562
2563         return 0;
2564
2565 error:
2566         kfree(_data);
2567         return ret;
2568 }
2569
2570 static int __ffs_data_got_strings(struct ffs_data *ffs,
2571                                   char *const _data, size_t len)
2572 {
2573         u32 str_count, needed_count, lang_count;
2574         struct usb_gadget_strings **stringtabs, *t;
2575         const char *data = _data;
2576         struct usb_string *s;
2577
2578         ENTER();
2579
2580         if (unlikely(len < 16 ||
2581                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2582                      get_unaligned_le32(data + 4) != len))
2583                 goto error;
2584         str_count  = get_unaligned_le32(data + 8);
2585         lang_count = get_unaligned_le32(data + 12);
2586
2587         /* if one is zero the other must be zero */
2588         if (unlikely(!str_count != !lang_count))
2589                 goto error;
2590
2591         /* Do we have at least as many strings as descriptors need? */
2592         needed_count = ffs->strings_count;
2593         if (unlikely(str_count < needed_count))
2594                 goto error;
2595
2596         /*
2597          * If we don't need any strings just return and free all
2598          * memory.
2599          */
2600         if (!needed_count) {
2601                 kfree(_data);
2602                 return 0;
2603         }
2604
2605         /* Allocate everything in one chunk so there's less maintenance. */
2606         {
2607                 unsigned i = 0;
2608                 vla_group(d);
2609                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2610                         lang_count + 1);
2611                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2612                 vla_item(d, struct usb_string, strings,
2613                         lang_count*(needed_count+1));
2614
2615                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2616
2617                 if (unlikely(!vlabuf)) {
2618                         kfree(_data);
2619                         return -ENOMEM;
2620                 }
2621
2622                 /* Initialize the VLA pointers */
2623                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2624                 t = vla_ptr(vlabuf, d, stringtab);
2625                 i = lang_count;
2626                 do {
2627                         *stringtabs++ = t++;
2628                 } while (--i);
2629                 *stringtabs = NULL;
2630
2631                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2632                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2633                 t = vla_ptr(vlabuf, d, stringtab);
2634                 s = vla_ptr(vlabuf, d, strings);
2635         }
2636
2637         /* For each language */
2638         data += 16;
2639         len -= 16;
2640
2641         do { /* lang_count > 0 so we can use do-while */
2642                 unsigned needed = needed_count;
2643
2644                 if (unlikely(len < 3))
2645                         goto error_free;
2646                 t->language = get_unaligned_le16(data);
2647                 t->strings  = s;
2648                 ++t;
2649
2650                 data += 2;
2651                 len -= 2;
2652
2653                 /* For each string */
2654                 do { /* str_count > 0 so we can use do-while */
2655                         size_t length = strnlen(data, len);
2656
2657                         if (unlikely(length == len))
2658                                 goto error_free;
2659
2660                         /*
2661                          * User may provide more strings then we need,
2662                          * if that's the case we simply ignore the
2663                          * rest
2664                          */
2665                         if (likely(needed)) {
2666                                 /*
2667                                  * s->id will be set while adding
2668                                  * function to configuration so for
2669                                  * now just leave garbage here.
2670                                  */
2671                                 s->s = data;
2672                                 --needed;
2673                                 ++s;
2674                         }
2675
2676                         data += length + 1;
2677                         len -= length + 1;
2678                 } while (--str_count);
2679
2680                 s->id = 0;   /* terminator */
2681                 s->s = NULL;
2682                 ++s;
2683
2684         } while (--lang_count);
2685
2686         /* Some garbage left? */
2687         if (unlikely(len))
2688                 goto error_free;
2689
2690         /* Done! */
2691         ffs->stringtabs = stringtabs;
2692         ffs->raw_strings = _data;
2693
2694         return 0;
2695
2696 error_free:
2697         kfree(stringtabs);
2698 error:
2699         kfree(_data);
2700         return -EINVAL;
2701 }
2702
2703
2704 /* Events handling and management *******************************************/
2705
2706 static void __ffs_event_add(struct ffs_data *ffs,
2707                             enum usb_functionfs_event_type type)
2708 {
2709         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2710         int neg = 0;
2711
2712         /*
2713          * Abort any unhandled setup
2714          *
2715          * We do not need to worry about some cmpxchg() changing value
2716          * of ffs->setup_state without holding the lock because when
2717          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2718          * the source does nothing.
2719          */
2720         if (ffs->setup_state == FFS_SETUP_PENDING)
2721                 ffs->setup_state = FFS_SETUP_CANCELLED;
2722
2723         /*
2724          * Logic of this function guarantees that there are at most four pending
2725          * evens on ffs->ev.types queue.  This is important because the queue
2726          * has space for four elements only and __ffs_ep0_read_events function
2727          * depends on that limit as well.  If more event types are added, those
2728          * limits have to be revisited or guaranteed to still hold.
2729          */
2730         switch (type) {
2731         case FUNCTIONFS_RESUME:
2732                 rem_type2 = FUNCTIONFS_SUSPEND;
2733                 /* FALL THROUGH */
2734         case FUNCTIONFS_SUSPEND:
2735         case FUNCTIONFS_SETUP:
2736                 rem_type1 = type;
2737                 /* Discard all similar events */
2738                 break;
2739
2740         case FUNCTIONFS_BIND:
2741         case FUNCTIONFS_UNBIND:
2742         case FUNCTIONFS_DISABLE:
2743         case FUNCTIONFS_ENABLE:
2744                 /* Discard everything other then power management. */
2745                 rem_type1 = FUNCTIONFS_SUSPEND;
2746                 rem_type2 = FUNCTIONFS_RESUME;
2747                 neg = 1;
2748                 break;
2749
2750         default:
2751                 WARN(1, "%d: unknown event, this should not happen\n", type);
2752                 return;
2753         }
2754
2755         {
2756                 u8 *ev  = ffs->ev.types, *out = ev;
2757                 unsigned n = ffs->ev.count;
2758                 for (; n; --n, ++ev)
2759                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2760                                 *out++ = *ev;
2761                         else
2762                                 pr_vdebug("purging event %d\n", *ev);
2763                 ffs->ev.count = out - ffs->ev.types;
2764         }
2765
2766         pr_vdebug("adding event %d\n", type);
2767         ffs->ev.types[ffs->ev.count++] = type;
2768         wake_up_locked(&ffs->ev.waitq);
2769         if (ffs->ffs_eventfd)
2770                 eventfd_signal(ffs->ffs_eventfd, 1);
2771 }
2772
2773 static void ffs_event_add(struct ffs_data *ffs,
2774                           enum usb_functionfs_event_type type)
2775 {
2776         unsigned long flags;
2777         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2778         __ffs_event_add(ffs, type);
2779         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2780 }
2781
2782 /* Bind/unbind USB function hooks *******************************************/
2783
2784 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2785 {
2786         int i;
2787
2788         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2789                 if (ffs->eps_addrmap[i] == endpoint_address)
2790                         return i;
2791         return -ENOENT;
2792 }
2793
2794 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2795                                     struct usb_descriptor_header *desc,
2796                                     void *priv)
2797 {
2798         struct usb_endpoint_descriptor *ds = (void *)desc;
2799         struct ffs_function *func = priv;
2800         struct ffs_ep *ffs_ep;
2801         unsigned ep_desc_id;
2802         int idx;
2803         static const char *speed_names[] = { "full", "high", "super" };
2804
2805         if (type != FFS_DESCRIPTOR)
2806                 return 0;
2807
2808         /*
2809          * If ss_descriptors is not NULL, we are reading super speed
2810          * descriptors; if hs_descriptors is not NULL, we are reading high
2811          * speed descriptors; otherwise, we are reading full speed
2812          * descriptors.
2813          */
2814         if (func->function.ss_descriptors) {
2815                 ep_desc_id = 2;
2816                 func->function.ss_descriptors[(long)valuep] = desc;
2817         } else if (func->function.hs_descriptors) {
2818                 ep_desc_id = 1;
2819                 func->function.hs_descriptors[(long)valuep] = desc;
2820         } else {
2821                 ep_desc_id = 0;
2822                 func->function.fs_descriptors[(long)valuep]    = desc;
2823         }
2824
2825         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2826                 return 0;
2827
2828         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2829         if (idx < 0)
2830                 return idx;
2831
2832         ffs_ep = func->eps + idx;
2833
2834         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2835                 pr_err("two %sspeed descriptors for EP %d\n",
2836                           speed_names[ep_desc_id],
2837                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2838                 return -EINVAL;
2839         }
2840         ffs_ep->descs[ep_desc_id] = ds;
2841
2842         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2843         if (ffs_ep->ep) {
2844                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2845                 if (!ds->wMaxPacketSize)
2846                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2847         } else {
2848                 struct usb_request *req;
2849                 struct usb_ep *ep;
2850                 u8 bEndpointAddress;
2851                 u16 wMaxPacketSize;
2852
2853                 /*
2854                  * We back up bEndpointAddress because autoconfig overwrites
2855                  * it with physical endpoint address.
2856                  */
2857                 bEndpointAddress = ds->bEndpointAddress;
2858                 /*
2859                  * We back up wMaxPacketSize because autoconfig treats
2860                  * endpoint descriptors as if they were full speed.
2861                  */
2862                 wMaxPacketSize = ds->wMaxPacketSize;
2863                 pr_vdebug("autoconfig\n");
2864                 ep = usb_ep_autoconfig(func->gadget, ds);
2865                 if (unlikely(!ep))
2866                         return -ENOTSUPP;
2867                 ep->driver_data = func->eps + idx;
2868
2869                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2870                 if (unlikely(!req))
2871                         return -ENOMEM;
2872
2873                 ffs_ep->ep  = ep;
2874                 ffs_ep->req = req;
2875                 func->eps_revmap[ds->bEndpointAddress &
2876                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2877                 /*
2878                  * If we use virtual address mapping, we restore
2879                  * original bEndpointAddress value.
2880                  */
2881                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2882                         ds->bEndpointAddress = bEndpointAddress;
2883                 /*
2884                  * Restore wMaxPacketSize which was potentially
2885                  * overwritten by autoconfig.
2886                  */
2887                 ds->wMaxPacketSize = wMaxPacketSize;
2888         }
2889         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2890
2891         return 0;
2892 }
2893
2894 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2895                                    struct usb_descriptor_header *desc,
2896                                    void *priv)
2897 {
2898         struct ffs_function *func = priv;
2899         unsigned idx;
2900         u8 newValue;
2901
2902         switch (type) {
2903         default:
2904         case FFS_DESCRIPTOR:
2905                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2906                 return 0;
2907
2908         case FFS_INTERFACE:
2909                 idx = *valuep;
2910                 if (func->interfaces_nums[idx] < 0) {
2911                         int id = usb_interface_id(func->conf, &func->function);
2912                         if (unlikely(id < 0))
2913                                 return id;
2914                         func->interfaces_nums[idx] = id;
2915                 }
2916                 newValue = func->interfaces_nums[idx];
2917                 break;
2918
2919         case FFS_STRING:
2920                 /* String' IDs are allocated when fsf_data is bound to cdev */
2921                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2922                 break;
2923
2924         case FFS_ENDPOINT:
2925                 /*
2926                  * USB_DT_ENDPOINT are handled in
2927                  * __ffs_func_bind_do_descs().
2928                  */
2929                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2930                         return 0;
2931
2932                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2933                 if (unlikely(!func->eps[idx].ep))
2934                         return -EINVAL;
2935
2936                 {
2937                         struct usb_endpoint_descriptor **descs;
2938                         descs = func->eps[idx].descs;
2939                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2940                 }
2941                 break;
2942         }
2943
2944         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2945         *valuep = newValue;
2946         return 0;
2947 }
2948
2949 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2950                                       struct usb_os_desc_header *h, void *data,
2951                                       unsigned len, void *priv)
2952 {
2953         struct ffs_function *func = priv;
2954         u8 length = 0;
2955
2956         switch (type) {
2957         case FFS_OS_DESC_EXT_COMPAT: {
2958                 struct usb_ext_compat_desc *desc = data;
2959                 struct usb_os_desc_table *t;
2960
2961                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2962                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2963                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2964                        ARRAY_SIZE(desc->CompatibleID) +
2965                        ARRAY_SIZE(desc->SubCompatibleID));
2966                 length = sizeof(*desc);
2967         }
2968                 break;
2969         case FFS_OS_DESC_EXT_PROP: {
2970                 struct usb_ext_prop_desc *desc = data;
2971                 struct usb_os_desc_table *t;
2972                 struct usb_os_desc_ext_prop *ext_prop;
2973                 char *ext_prop_name;
2974                 char *ext_prop_data;
2975
2976                 t = &func->function.os_desc_table[h->interface];
2977                 t->if_id = func->interfaces_nums[h->interface];
2978
2979                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2980                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2981
2982                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2983                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2984                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2985                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2986                 length = ext_prop->name_len + ext_prop->data_len + 14;
2987
2988                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2989                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2990                         ext_prop->name_len;
2991
2992                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2993                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2994                         ext_prop->data_len;
2995                 memcpy(ext_prop_data,
2996                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2997                        ext_prop->data_len);
2998                 /* unicode data reported to the host as "WCHAR"s */
2999                 switch (ext_prop->type) {
3000                 case USB_EXT_PROP_UNICODE:
3001                 case USB_EXT_PROP_UNICODE_ENV:
3002                 case USB_EXT_PROP_UNICODE_LINK:
3003                 case USB_EXT_PROP_UNICODE_MULTI:
3004                         ext_prop->data_len *= 2;
3005                         break;
3006                 }
3007                 ext_prop->data = ext_prop_data;
3008
3009                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3010                        ext_prop->name_len);
3011                 /* property name reported to the host as "WCHAR"s */
3012                 ext_prop->name_len *= 2;
3013                 ext_prop->name = ext_prop_name;
3014
3015                 t->os_desc->ext_prop_len +=
3016                         ext_prop->name_len + ext_prop->data_len + 14;
3017                 ++t->os_desc->ext_prop_count;
3018                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3019         }
3020                 break;
3021         default:
3022                 pr_vdebug("unknown descriptor: %d\n", type);
3023         }
3024
3025         return length;
3026 }
3027
3028 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3029                                                 struct usb_configuration *c)
3030 {
3031         struct ffs_function *func = ffs_func_from_usb(f);
3032         struct f_fs_opts *ffs_opts =
3033                 container_of(f->fi, struct f_fs_opts, func_inst);
3034         int ret;
3035
3036         ENTER();
3037
3038         /*
3039          * Legacy gadget triggers binding in functionfs_ready_callback,
3040          * which already uses locking; taking the same lock here would
3041          * cause a deadlock.
3042          *
3043          * Configfs-enabled gadgets however do need ffs_dev_lock.
3044          */
3045         if (!ffs_opts->no_configfs)
3046                 ffs_dev_lock();
3047         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3048         func->ffs = ffs_opts->dev->ffs_data;
3049         if (!ffs_opts->no_configfs)
3050                 ffs_dev_unlock();
3051         if (ret)
3052                 return ERR_PTR(ret);
3053
3054         func->conf = c;
3055         func->gadget = c->cdev->gadget;
3056
3057         /*
3058          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3059          * configurations are bound in sequence with list_for_each_entry,
3060          * in each configuration its functions are bound in sequence
3061          * with list_for_each_entry, so we assume no race condition
3062          * with regard to ffs_opts->bound access
3063          */
3064         if (!ffs_opts->refcnt) {
3065                 ret = functionfs_bind(func->ffs, c->cdev);
3066                 if (ret)
3067                         return ERR_PTR(ret);
3068         }
3069         ffs_opts->refcnt++;
3070         func->function.strings = func->ffs->stringtabs;
3071
3072         return ffs_opts;
3073 }
3074
3075 static int _ffs_func_bind(struct usb_configuration *c,
3076                           struct usb_function *f)
3077 {
3078         struct ffs_function *func = ffs_func_from_usb(f);
3079         struct ffs_data *ffs = func->ffs;
3080
3081         const int full = !!func->ffs->fs_descs_count;
3082         const int high = !!func->ffs->hs_descs_count;
3083         const int super = !!func->ffs->ss_descs_count;
3084
3085         int fs_len, hs_len, ss_len, ret, i;
3086         struct ffs_ep *eps_ptr;
3087
3088         /* Make it a single chunk, less management later on */
3089         vla_group(d);
3090         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3091         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3092                 full ? ffs->fs_descs_count + 1 : 0);
3093         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3094                 high ? ffs->hs_descs_count + 1 : 0);
3095         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3096                 super ? ffs->ss_descs_count + 1 : 0);
3097         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3098         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3099                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3100         vla_item_with_sz(d, char[16], ext_compat,
3101                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3102         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3103                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3104         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3105                          ffs->ms_os_descs_ext_prop_count);
3106         vla_item_with_sz(d, char, ext_prop_name,
3107                          ffs->ms_os_descs_ext_prop_name_len);
3108         vla_item_with_sz(d, char, ext_prop_data,
3109                          ffs->ms_os_descs_ext_prop_data_len);
3110         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3111         char *vlabuf;
3112
3113         ENTER();
3114
3115         /* Has descriptors only for speeds gadget does not support */
3116         if (unlikely(!(full | high | super)))
3117                 return -ENOTSUPP;
3118
3119         /* Allocate a single chunk, less management later on */
3120         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3121         if (unlikely(!vlabuf))
3122                 return -ENOMEM;
3123
3124         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3125         ffs->ms_os_descs_ext_prop_name_avail =
3126                 vla_ptr(vlabuf, d, ext_prop_name);
3127         ffs->ms_os_descs_ext_prop_data_avail =
3128                 vla_ptr(vlabuf, d, ext_prop_data);
3129
3130         /* Copy descriptors  */
3131         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3132                ffs->raw_descs_length);
3133
3134         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3135         eps_ptr = vla_ptr(vlabuf, d, eps);
3136         for (i = 0; i < ffs->eps_count; i++)
3137                 eps_ptr[i].num = -1;
3138
3139         /* Save pointers
3140          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3141         */
3142         func->eps             = vla_ptr(vlabuf, d, eps);
3143         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3144
3145         /*
3146          * Go through all the endpoint descriptors and allocate
3147          * endpoints first, so that later we can rewrite the endpoint
3148          * numbers without worrying that it may be described later on.
3149          */
3150         if (likely(full)) {
3151                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3152                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3153                                       vla_ptr(vlabuf, d, raw_descs),
3154                                       d_raw_descs__sz,
3155                                       __ffs_func_bind_do_descs, func);
3156                 if (unlikely(fs_len < 0)) {
3157                         ret = fs_len;
3158                         goto error;
3159                 }
3160         } else {
3161                 fs_len = 0;
3162         }
3163
3164         if (likely(high)) {
3165                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3166                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3167                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3168                                       d_raw_descs__sz - fs_len,
3169                                       __ffs_func_bind_do_descs, func);
3170                 if (unlikely(hs_len < 0)) {
3171                         ret = hs_len;
3172                         goto error;
3173                 }
3174         } else {
3175                 hs_len = 0;
3176         }
3177
3178         if (likely(super)) {
3179                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3180                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3181                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3182                                 d_raw_descs__sz - fs_len - hs_len,
3183                                 __ffs_func_bind_do_descs, func);
3184                 if (unlikely(ss_len < 0)) {
3185                         ret = ss_len;
3186                         goto error;
3187                 }
3188         } else {
3189                 ss_len = 0;
3190         }
3191
3192         /*
3193          * Now handle interface numbers allocation and interface and
3194          * endpoint numbers rewriting.  We can do that in one go
3195          * now.
3196          */
3197         ret = ffs_do_descs(ffs->fs_descs_count +
3198                            (high ? ffs->hs_descs_count : 0) +
3199                            (super ? ffs->ss_descs_count : 0),
3200                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3201                            __ffs_func_bind_do_nums, func);
3202         if (unlikely(ret < 0))
3203                 goto error;
3204
3205         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3206         if (c->cdev->use_os_string) {
3207                 for (i = 0; i < ffs->interfaces_count; ++i) {
3208                         struct usb_os_desc *desc;
3209
3210                         desc = func->function.os_desc_table[i].os_desc =
3211                                 vla_ptr(vlabuf, d, os_desc) +
3212                                 i * sizeof(struct usb_os_desc);
3213                         desc->ext_compat_id =
3214                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3215                         INIT_LIST_HEAD(&desc->ext_prop);
3216                 }
3217                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3218                                       vla_ptr(vlabuf, d, raw_descs) +
3219                                       fs_len + hs_len + ss_len,
3220                                       d_raw_descs__sz - fs_len - hs_len -
3221                                       ss_len,
3222                                       __ffs_func_bind_do_os_desc, func);
3223                 if (unlikely(ret < 0))
3224                         goto error;
3225         }
3226         func->function.os_desc_n =
3227                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3228
3229         /* And we're done */
3230         ffs_event_add(ffs, FUNCTIONFS_BIND);
3231         return 0;
3232
3233 error:
3234         /* XXX Do we need to release all claimed endpoints here? */
3235         return ret;
3236 }
3237
3238 static int ffs_func_bind(struct usb_configuration *c,
3239                          struct usb_function *f)
3240 {
3241         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3242         struct ffs_function *func = ffs_func_from_usb(f);
3243         int ret;
3244
3245         if (IS_ERR(ffs_opts))
3246                 return PTR_ERR(ffs_opts);
3247
3248         ret = _ffs_func_bind(c, f);
3249         if (ret && !--ffs_opts->refcnt)
3250                 functionfs_unbind(func->ffs);
3251
3252         return ret;
3253 }
3254
3255
3256 /* Other USB function hooks *************************************************/
3257
3258 static void ffs_reset_work(struct work_struct *work)
3259 {
3260         struct ffs_data *ffs = container_of(work,
3261                 struct ffs_data, reset_work);
3262         ffs_data_reset(ffs);
3263 }
3264
3265 static int ffs_func_set_alt(struct usb_function *f,
3266                             unsigned interface, unsigned alt)
3267 {
3268         struct ffs_function *func = ffs_func_from_usb(f);
3269         struct ffs_data *ffs = func->ffs;
3270         int ret = 0, intf;
3271
3272         if (alt != (unsigned)-1) {
3273                 intf = ffs_func_revmap_intf(func, interface);
3274                 if (unlikely(intf < 0))
3275                         return intf;
3276         }
3277
3278         if (ffs->func)
3279                 ffs_func_eps_disable(ffs->func);
3280
3281         if (ffs->state == FFS_DEACTIVATED) {
3282                 ffs->state = FFS_CLOSING;
3283                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3284                 schedule_work(&ffs->reset_work);
3285                 return -ENODEV;
3286         }
3287
3288         if (ffs->state != FFS_ACTIVE)
3289                 return -ENODEV;
3290
3291         if (alt == (unsigned)-1) {
3292                 ffs->func = NULL;
3293                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3294                 return 0;
3295         }
3296
3297         ffs->func = func;
3298         ret = ffs_func_eps_enable(func);
3299         if (likely(ret >= 0))
3300                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3301         return ret;
3302 }
3303
3304 static void ffs_func_disable(struct usb_function *f)
3305 {
3306         ffs_func_set_alt(f, 0, (unsigned)-1);
3307 }
3308
3309 static int ffs_func_setup(struct usb_function *f,
3310                           const struct usb_ctrlrequest *creq)
3311 {
3312         struct ffs_function *func = ffs_func_from_usb(f);
3313         struct ffs_data *ffs = func->ffs;
3314         unsigned long flags;
3315         int ret;
3316
3317         ENTER();
3318
3319         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3320         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3321         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3322         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3323         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3324
3325         /*
3326          * Most requests directed to interface go through here
3327          * (notable exceptions are set/get interface) so we need to
3328          * handle them.  All other either handled by composite or
3329          * passed to usb_configuration->setup() (if one is set).  No
3330          * matter, we will handle requests directed to endpoint here
3331          * as well (as it's straightforward).  Other request recipient
3332          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3333          * is being used.
3334          */
3335         if (ffs->state != FFS_ACTIVE)
3336                 return -ENODEV;
3337
3338         switch (creq->bRequestType & USB_RECIP_MASK) {
3339         case USB_RECIP_INTERFACE:
3340                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3341                 if (unlikely(ret < 0))
3342                         return ret;
3343                 break;
3344
3345         case USB_RECIP_ENDPOINT:
3346                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3347                 if (unlikely(ret < 0))
3348                         return ret;
3349                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3350                         ret = func->ffs->eps_addrmap[ret];
3351                 break;
3352
3353         default:
3354                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3355                         ret = le16_to_cpu(creq->wIndex);
3356                 else
3357                         return -EOPNOTSUPP;
3358         }
3359
3360         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3361         ffs->ev.setup = *creq;
3362         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3363         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3364         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3365
3366         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3367 }
3368
3369 static bool ffs_func_req_match(struct usb_function *f,
3370                                const struct usb_ctrlrequest *creq,
3371                                bool config0)
3372 {
3373         struct ffs_function *func = ffs_func_from_usb(f);
3374
3375         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3376                 return false;
3377
3378         switch (creq->bRequestType & USB_RECIP_MASK) {
3379         case USB_RECIP_INTERFACE:
3380                 return (ffs_func_revmap_intf(func,
3381                                              le16_to_cpu(creq->wIndex)) >= 0);
3382         case USB_RECIP_ENDPOINT:
3383                 return (ffs_func_revmap_ep(func,
3384                                            le16_to_cpu(creq->wIndex)) >= 0);
3385         default:
3386                 return (bool) (func->ffs->user_flags &
3387                                FUNCTIONFS_ALL_CTRL_RECIP);
3388         }
3389 }
3390
3391 static void ffs_func_suspend(struct usb_function *f)
3392 {
3393         ENTER();
3394         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3395 }
3396
3397 static void ffs_func_resume(struct usb_function *f)
3398 {
3399         ENTER();
3400         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3401 }
3402
3403
3404 /* Endpoint and interface numbers reverse mapping ***************************/
3405
3406 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3407 {
3408         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3409         return num ? num : -EDOM;
3410 }
3411
3412 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3413 {
3414         short *nums = func->interfaces_nums;
3415         unsigned count = func->ffs->interfaces_count;
3416
3417         for (; count; --count, ++nums) {
3418                 if (*nums >= 0 && *nums == intf)
3419                         return nums - func->interfaces_nums;
3420         }
3421
3422         return -EDOM;
3423 }
3424
3425
3426 /* Devices management *******************************************************/
3427
3428 static LIST_HEAD(ffs_devices);
3429
3430 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3431 {
3432         struct ffs_dev *dev;
3433
3434         if (!name)
3435                 return NULL;
3436
3437         list_for_each_entry(dev, &ffs_devices, entry) {
3438                 if (strcmp(dev->name, name) == 0)
3439                         return dev;
3440         }
3441
3442         return NULL;
3443 }
3444
3445 /*
3446  * ffs_lock must be taken by the caller of this function
3447  */
3448 static struct ffs_dev *_ffs_get_single_dev(void)
3449 {
3450         struct ffs_dev *dev;
3451
3452         if (list_is_singular(&ffs_devices)) {
3453                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3454                 if (dev->single)
3455                         return dev;
3456         }
3457
3458         return NULL;
3459 }
3460
3461 /*
3462  * ffs_lock must be taken by the caller of this function
3463  */
3464 static struct ffs_dev *_ffs_find_dev(const char *name)
3465 {
3466         struct ffs_dev *dev;
3467
3468         dev = _ffs_get_single_dev();
3469         if (dev)
3470                 return dev;
3471
3472         return _ffs_do_find_dev(name);
3473 }
3474
3475 /* Configfs support *********************************************************/
3476
3477 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3478 {
3479         return container_of(to_config_group(item), struct f_fs_opts,
3480                             func_inst.group);
3481 }
3482
3483 static void ffs_attr_release(struct config_item *item)
3484 {
3485         struct f_fs_opts *opts = to_ffs_opts(item);
3486
3487         usb_put_function_instance(&opts->func_inst);
3488 }
3489
3490 static struct configfs_item_operations ffs_item_ops = {
3491         .release        = ffs_attr_release,
3492 };
3493
3494 static const struct config_item_type ffs_func_type = {
3495         .ct_item_ops    = &ffs_item_ops,
3496         .ct_owner       = THIS_MODULE,
3497 };
3498
3499
3500 /* Function registration interface ******************************************/
3501
3502 static void ffs_free_inst(struct usb_function_instance *f)
3503 {
3504         struct f_fs_opts *opts;
3505
3506         opts = to_f_fs_opts(f);
3507         ffs_dev_lock();
3508         _ffs_free_dev(opts->dev);
3509         ffs_dev_unlock();
3510         kfree(opts);
3511 }
3512
3513 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3514 {
3515         if (strlen(name) >= FIELD_SIZEOF(struct ffs_dev, name))
3516                 return -ENAMETOOLONG;
3517         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3518 }
3519
3520 static struct usb_function_instance *ffs_alloc_inst(void)
3521 {
3522         struct f_fs_opts *opts;
3523         struct ffs_dev *dev;
3524
3525         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3526         if (!opts)
3527                 return ERR_PTR(-ENOMEM);
3528
3529         opts->func_inst.set_inst_name = ffs_set_inst_name;
3530         opts->func_inst.free_func_inst = ffs_free_inst;
3531         ffs_dev_lock();
3532         dev = _ffs_alloc_dev();
3533         ffs_dev_unlock();
3534         if (IS_ERR(dev)) {
3535                 kfree(opts);
3536                 return ERR_CAST(dev);
3537         }
3538         opts->dev = dev;
3539         dev->opts = opts;
3540
3541         config_group_init_type_name(&opts->func_inst.group, "",
3542                                     &ffs_func_type);
3543         return &opts->func_inst;
3544 }
3545
3546 static void ffs_free(struct usb_function *f)
3547 {
3548         kfree(ffs_func_from_usb(f));
3549 }
3550
3551 static void ffs_func_unbind(struct usb_configuration *c,
3552                             struct usb_function *f)
3553 {
3554         struct ffs_function *func = ffs_func_from_usb(f);
3555         struct ffs_data *ffs = func->ffs;
3556         struct f_fs_opts *opts =
3557                 container_of(f->fi, struct f_fs_opts, func_inst);
3558         struct ffs_ep *ep = func->eps;
3559         unsigned count = ffs->eps_count;
3560         unsigned long flags;
3561
3562         ENTER();
3563         if (ffs->func == func) {
3564                 ffs_func_eps_disable(func);
3565                 ffs->func = NULL;
3566         }
3567
3568         if (!--opts->refcnt)
3569                 functionfs_unbind(ffs);
3570
3571         /* cleanup after autoconfig */
3572         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3573         while (count--) {
3574                 if (ep->ep && ep->req)
3575                         usb_ep_free_request(ep->ep, ep->req);
3576                 ep->req = NULL;
3577                 ++ep;
3578         }
3579         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3580         kfree(func->eps);
3581         func->eps = NULL;
3582         /*
3583          * eps, descriptors and interfaces_nums are allocated in the
3584          * same chunk so only one free is required.
3585          */
3586         func->function.fs_descriptors = NULL;
3587         func->function.hs_descriptors = NULL;
3588         func->function.ss_descriptors = NULL;
3589         func->interfaces_nums = NULL;
3590
3591         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3592 }
3593
3594 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3595 {
3596         struct ffs_function *func;
3597
3598         ENTER();
3599
3600         func = kzalloc(sizeof(*func), GFP_KERNEL);
3601         if (unlikely(!func))
3602                 return ERR_PTR(-ENOMEM);
3603
3604         func->function.name    = "Function FS Gadget";
3605
3606         func->function.bind    = ffs_func_bind;
3607         func->function.unbind  = ffs_func_unbind;
3608         func->function.set_alt = ffs_func_set_alt;
3609         func->function.disable = ffs_func_disable;
3610         func->function.setup   = ffs_func_setup;
3611         func->function.req_match = ffs_func_req_match;
3612         func->function.suspend = ffs_func_suspend;
3613         func->function.resume  = ffs_func_resume;
3614         func->function.free_func = ffs_free;
3615
3616         return &func->function;
3617 }
3618
3619 /*
3620  * ffs_lock must be taken by the caller of this function
3621  */
3622 static struct ffs_dev *_ffs_alloc_dev(void)
3623 {
3624         struct ffs_dev *dev;
3625         int ret;
3626
3627         if (_ffs_get_single_dev())
3628                         return ERR_PTR(-EBUSY);
3629
3630         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3631         if (!dev)
3632                 return ERR_PTR(-ENOMEM);
3633
3634         if (list_empty(&ffs_devices)) {
3635                 ret = functionfs_init();
3636                 if (ret) {
3637                         kfree(dev);
3638                         return ERR_PTR(ret);
3639                 }
3640         }
3641
3642         list_add(&dev->entry, &ffs_devices);
3643
3644         return dev;
3645 }
3646
3647 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3648 {
3649         struct ffs_dev *existing;
3650         int ret = 0;
3651
3652         ffs_dev_lock();
3653
3654         existing = _ffs_do_find_dev(name);
3655         if (!existing)
3656                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3657         else if (existing != dev)
3658                 ret = -EBUSY;
3659
3660         ffs_dev_unlock();
3661
3662         return ret;
3663 }
3664 EXPORT_SYMBOL_GPL(ffs_name_dev);
3665
3666 int ffs_single_dev(struct ffs_dev *dev)
3667 {
3668         int ret;
3669
3670         ret = 0;
3671         ffs_dev_lock();
3672
3673         if (!list_is_singular(&ffs_devices))
3674                 ret = -EBUSY;
3675         else
3676                 dev->single = true;
3677
3678         ffs_dev_unlock();
3679         return ret;
3680 }
3681 EXPORT_SYMBOL_GPL(ffs_single_dev);
3682
3683 /*
3684  * ffs_lock must be taken by the caller of this function
3685  */
3686 static void _ffs_free_dev(struct ffs_dev *dev)
3687 {
3688         list_del(&dev->entry);
3689
3690         /* Clear the private_data pointer to stop incorrect dev access */
3691         if (dev->ffs_data)
3692                 dev->ffs_data->private_data = NULL;
3693
3694         kfree(dev);
3695         if (list_empty(&ffs_devices))
3696                 functionfs_cleanup();
3697 }
3698
3699 static void *ffs_acquire_dev(const char *dev_name)
3700 {
3701         struct ffs_dev *ffs_dev;
3702
3703         ENTER();
3704         ffs_dev_lock();
3705
3706         ffs_dev = _ffs_find_dev(dev_name);
3707         if (!ffs_dev)
3708                 ffs_dev = ERR_PTR(-ENOENT);
3709         else if (ffs_dev->mounted)
3710                 ffs_dev = ERR_PTR(-EBUSY);
3711         else if (ffs_dev->ffs_acquire_dev_callback &&
3712             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3713                 ffs_dev = ERR_PTR(-ENOENT);
3714         else
3715                 ffs_dev->mounted = true;
3716
3717         ffs_dev_unlock();
3718         return ffs_dev;
3719 }
3720
3721 static void ffs_release_dev(struct ffs_data *ffs_data)
3722 {
3723         struct ffs_dev *ffs_dev;
3724
3725         ENTER();
3726         ffs_dev_lock();
3727
3728         ffs_dev = ffs_data->private_data;
3729         if (ffs_dev) {
3730                 ffs_dev->mounted = false;
3731
3732                 if (ffs_dev->ffs_release_dev_callback)
3733                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3734         }
3735
3736         ffs_dev_unlock();
3737 }
3738
3739 static int ffs_ready(struct ffs_data *ffs)
3740 {
3741         struct ffs_dev *ffs_obj;
3742         int ret = 0;
3743
3744         ENTER();
3745         ffs_dev_lock();
3746
3747         ffs_obj = ffs->private_data;
3748         if (!ffs_obj) {
3749                 ret = -EINVAL;
3750                 goto done;
3751         }
3752         if (WARN_ON(ffs_obj->desc_ready)) {
3753                 ret = -EBUSY;
3754                 goto done;
3755         }
3756
3757         ffs_obj->desc_ready = true;
3758         ffs_obj->ffs_data = ffs;
3759
3760         if (ffs_obj->ffs_ready_callback) {
3761                 ret = ffs_obj->ffs_ready_callback(ffs);
3762                 if (ret)
3763                         goto done;
3764         }
3765
3766         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3767 done:
3768         ffs_dev_unlock();
3769         return ret;
3770 }
3771
3772 static void ffs_closed(struct ffs_data *ffs)
3773 {
3774         struct ffs_dev *ffs_obj;
3775         struct f_fs_opts *opts;
3776         struct config_item *ci;
3777
3778         ENTER();
3779         ffs_dev_lock();
3780
3781         ffs_obj = ffs->private_data;
3782         if (!ffs_obj)
3783                 goto done;
3784
3785         ffs_obj->desc_ready = false;
3786         ffs_obj->ffs_data = NULL;
3787
3788         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3789             ffs_obj->ffs_closed_callback)
3790                 ffs_obj->ffs_closed_callback(ffs);
3791
3792         if (ffs_obj->opts)
3793                 opts = ffs_obj->opts;
3794         else
3795                 goto done;
3796
3797         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3798             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3799                 goto done;
3800
3801         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3802         ffs_dev_unlock();
3803
3804         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3805                 unregister_gadget_item(ci);
3806         return;
3807 done:
3808         ffs_dev_unlock();
3809 }
3810
3811 /* Misc helper functions ****************************************************/
3812
3813 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3814 {
3815         return nonblock
3816                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3817                 : mutex_lock_interruptible(mutex);
3818 }
3819
3820 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3821 {
3822         char *data;
3823
3824         if (unlikely(!len))
3825                 return NULL;
3826
3827         data = kmalloc(len, GFP_KERNEL);
3828         if (unlikely(!data))
3829                 return ERR_PTR(-ENOMEM);
3830
3831         if (unlikely(copy_from_user(data, buf, len))) {
3832                 kfree(data);
3833                 return ERR_PTR(-EFAULT);
3834         }
3835
3836         pr_vdebug("Buffer from user space:\n");
3837         ffs_dump_mem("", data, len);
3838
3839         return data;
3840 }
3841
3842 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3843 MODULE_LICENSE("GPL");
3844 MODULE_AUTHOR("Michal Nazarewicz");