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                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1001
1002                 spin_lock_irq(&epfile->ffs->eps_lock);
1003                 /* In the meantime, endpoint got disabled or changed. */
1004                 if (epfile->ep != ep) {
1005                         ret = -ESHUTDOWN;
1006                         goto error_lock;
1007                 }
1008                 data_len = iov_iter_count(&io_data->data);
1009                 /*
1010                  * Controller may require buffer size to be aligned to
1011                  * maxpacketsize of an out endpoint.
1012                  */
1013                 if (io_data->read)
1014                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1015                 spin_unlock_irq(&epfile->ffs->eps_lock);
1016
1017                 data = ffs_alloc_buffer(io_data, data_len);
1018                 if (unlikely(!data)) {
1019                         ret = -ENOMEM;
1020                         goto error_mutex;
1021                 }
1022                 if (!io_data->read &&
1023                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1024                         ret = -EFAULT;
1025                         goto error_mutex;
1026                 }
1027         }
1028
1029         spin_lock_irq(&epfile->ffs->eps_lock);
1030
1031         if (epfile->ep != ep) {
1032                 /* In the meantime, endpoint got disabled or changed. */
1033                 ret = -ESHUTDOWN;
1034         } else if (halt) {
1035                 ret = usb_ep_set_halt(ep->ep);
1036                 if (!ret)
1037                         ret = -EBADMSG;
1038         } else if (unlikely(data_len == -EINVAL)) {
1039                 /*
1040                  * Sanity Check: even though data_len can't be used
1041                  * uninitialized at the time I write this comment, some
1042                  * compilers complain about this situation.
1043                  * In order to keep the code clean from warnings, data_len is
1044                  * being initialized to -EINVAL during its declaration, which
1045                  * means we can't rely on compiler anymore to warn no future
1046                  * changes won't result in data_len being used uninitialized.
1047                  * For such reason, we're adding this redundant sanity check
1048                  * here.
1049                  */
1050                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1051                 ret = -EINVAL;
1052         } else if (!io_data->aio) {
1053                 DECLARE_COMPLETION_ONSTACK(done);
1054                 bool interrupted = false;
1055
1056                 req = ep->req;
1057                 if (io_data->use_sg) {
1058                         req->buf = NULL;
1059                         req->sg = io_data->sgt.sgl;
1060                         req->num_sgs = io_data->sgt.nents;
1061                 } else {
1062                         req->buf = data;
1063                 }
1064                 req->length = data_len;
1065
1066                 io_data->buf = data;
1067
1068                 req->context  = &done;
1069                 req->complete = ffs_epfile_io_complete;
1070
1071                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1072                 if (unlikely(ret < 0))
1073                         goto error_lock;
1074
1075                 spin_unlock_irq(&epfile->ffs->eps_lock);
1076
1077                 if (unlikely(wait_for_completion_interruptible(&done))) {
1078                         /*
1079                          * To avoid race condition with ffs_epfile_io_complete,
1080                          * dequeue the request first then check
1081                          * status. usb_ep_dequeue API should guarantee no race
1082                          * condition with req->complete callback.
1083                          */
1084                         usb_ep_dequeue(ep->ep, req);
1085                         wait_for_completion(&done);
1086                         interrupted = ep->status < 0;
1087                 }
1088
1089                 if (interrupted)
1090                         ret = -EINTR;
1091                 else if (io_data->read && ep->status > 0)
1092                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1093                                                      &io_data->data);
1094                 else
1095                         ret = ep->status;
1096                 goto error_mutex;
1097         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1098                 ret = -ENOMEM;
1099         } else {
1100                 if (io_data->use_sg) {
1101                         req->buf = NULL;
1102                         req->sg = io_data->sgt.sgl;
1103                         req->num_sgs = io_data->sgt.nents;
1104                 } else {
1105                         req->buf = data;
1106                 }
1107                 req->length = data_len;
1108
1109                 io_data->buf = data;
1110                 io_data->ep = ep->ep;
1111                 io_data->req = req;
1112                 io_data->ffs = epfile->ffs;
1113
1114                 req->context  = io_data;
1115                 req->complete = ffs_epfile_async_io_complete;
1116
1117                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1118                 if (unlikely(ret)) {
1119                         usb_ep_free_request(ep->ep, req);
1120                         goto error_lock;
1121                 }
1122
1123                 ret = -EIOCBQUEUED;
1124                 /*
1125                  * Do not kfree the buffer in this function.  It will be freed
1126                  * by ffs_user_copy_worker.
1127                  */
1128                 data = NULL;
1129         }
1130
1131 error_lock:
1132         spin_unlock_irq(&epfile->ffs->eps_lock);
1133 error_mutex:
1134         mutex_unlock(&epfile->mutex);
1135 error:
1136         ffs_free_buffer(io_data);
1137         return ret;
1138 }
1139
1140 static int
1141 ffs_epfile_open(struct inode *inode, struct file *file)
1142 {
1143         struct ffs_epfile *epfile = inode->i_private;
1144
1145         ENTER();
1146
1147         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1148                 return -ENODEV;
1149
1150         file->private_data = epfile;
1151         ffs_data_opened(epfile->ffs);
1152
1153         return 0;
1154 }
1155
1156 static int ffs_aio_cancel(struct kiocb *kiocb)
1157 {
1158         struct ffs_io_data *io_data = kiocb->private;
1159         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1160         int value;
1161
1162         ENTER();
1163
1164         spin_lock_irq(&epfile->ffs->eps_lock);
1165
1166         if (likely(io_data && io_data->ep && io_data->req))
1167                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1168         else
1169                 value = -EINVAL;
1170
1171         spin_unlock_irq(&epfile->ffs->eps_lock);
1172
1173         return value;
1174 }
1175
1176 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1177 {
1178         struct ffs_io_data io_data, *p = &io_data;
1179         ssize_t res;
1180
1181         ENTER();
1182
1183         if (!is_sync_kiocb(kiocb)) {
1184                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1185                 if (unlikely(!p))
1186                         return -ENOMEM;
1187                 p->aio = true;
1188         } else {
1189                 p->aio = false;
1190         }
1191
1192         p->read = false;
1193         p->kiocb = kiocb;
1194         p->data = *from;
1195         p->mm = current->mm;
1196
1197         kiocb->private = p;
1198
1199         if (p->aio)
1200                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1201
1202         res = ffs_epfile_io(kiocb->ki_filp, p);
1203         if (res == -EIOCBQUEUED)
1204                 return res;
1205         if (p->aio)
1206                 kfree(p);
1207         else
1208                 *from = p->data;
1209         return res;
1210 }
1211
1212 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1213 {
1214         struct ffs_io_data io_data, *p = &io_data;
1215         ssize_t res;
1216
1217         ENTER();
1218
1219         if (!is_sync_kiocb(kiocb)) {
1220                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1221                 if (unlikely(!p))
1222                         return -ENOMEM;
1223                 p->aio = true;
1224         } else {
1225                 p->aio = false;
1226         }
1227
1228         p->read = true;
1229         p->kiocb = kiocb;
1230         if (p->aio) {
1231                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1232                 if (!p->to_free) {
1233                         kfree(p);
1234                         return -ENOMEM;
1235                 }
1236         } else {
1237                 p->data = *to;
1238                 p->to_free = NULL;
1239         }
1240         p->mm = current->mm;
1241
1242         kiocb->private = p;
1243
1244         if (p->aio)
1245                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1246
1247         res = ffs_epfile_io(kiocb->ki_filp, p);
1248         if (res == -EIOCBQUEUED)
1249                 return res;
1250
1251         if (p->aio) {
1252                 kfree(p->to_free);
1253                 kfree(p);
1254         } else {
1255                 *to = p->data;
1256         }
1257         return res;
1258 }
1259
1260 static int
1261 ffs_epfile_release(struct inode *inode, struct file *file)
1262 {
1263         struct ffs_epfile *epfile = inode->i_private;
1264
1265         ENTER();
1266
1267         __ffs_epfile_read_buffer_free(epfile);
1268         ffs_data_closed(epfile->ffs);
1269
1270         return 0;
1271 }
1272
1273 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1274                              unsigned long value)
1275 {
1276         struct ffs_epfile *epfile = file->private_data;
1277         struct ffs_ep *ep;
1278         int ret;
1279
1280         ENTER();
1281
1282         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1283                 return -ENODEV;
1284
1285         /* Wait for endpoint to be enabled */
1286         ep = epfile->ep;
1287         if (!ep) {
1288                 if (file->f_flags & O_NONBLOCK)
1289                         return -EAGAIN;
1290
1291                 ret = wait_event_interruptible(
1292                                 epfile->ffs->wait, (ep = epfile->ep));
1293                 if (ret)
1294                         return -EINTR;
1295         }
1296
1297         spin_lock_irq(&epfile->ffs->eps_lock);
1298
1299         /* In the meantime, endpoint got disabled or changed. */
1300         if (epfile->ep != ep) {
1301                 spin_unlock_irq(&epfile->ffs->eps_lock);
1302                 return -ESHUTDOWN;
1303         }
1304
1305         switch (code) {
1306         case FUNCTIONFS_FIFO_STATUS:
1307                 ret = usb_ep_fifo_status(epfile->ep->ep);
1308                 break;
1309         case FUNCTIONFS_FIFO_FLUSH:
1310                 usb_ep_fifo_flush(epfile->ep->ep);
1311                 ret = 0;
1312                 break;
1313         case FUNCTIONFS_CLEAR_HALT:
1314                 ret = usb_ep_clear_halt(epfile->ep->ep);
1315                 break;
1316         case FUNCTIONFS_ENDPOINT_REVMAP:
1317                 ret = epfile->ep->num;
1318                 break;
1319         case FUNCTIONFS_ENDPOINT_DESC:
1320         {
1321                 int desc_idx;
1322                 struct usb_endpoint_descriptor *desc;
1323
1324                 switch (epfile->ffs->gadget->speed) {
1325                 case USB_SPEED_SUPER:
1326                         desc_idx = 2;
1327                         break;
1328                 case USB_SPEED_HIGH:
1329                         desc_idx = 1;
1330                         break;
1331                 default:
1332                         desc_idx = 0;
1333                 }
1334                 desc = epfile->ep->descs[desc_idx];
1335
1336                 spin_unlock_irq(&epfile->ffs->eps_lock);
1337                 ret = copy_to_user((void __user *)value, desc, desc->bLength);
1338                 if (ret)
1339                         ret = -EFAULT;
1340                 return ret;
1341         }
1342         default:
1343                 ret = -ENOTTY;
1344         }
1345         spin_unlock_irq(&epfile->ffs->eps_lock);
1346
1347         return ret;
1348 }
1349
1350 #ifdef CONFIG_COMPAT
1351 static long ffs_epfile_compat_ioctl(struct file *file, unsigned code,
1352                 unsigned long value)
1353 {
1354         return ffs_epfile_ioctl(file, code, value);
1355 }
1356 #endif
1357
1358 static const struct file_operations ffs_epfile_operations = {
1359         .llseek =       no_llseek,
1360
1361         .open =         ffs_epfile_open,
1362         .write_iter =   ffs_epfile_write_iter,
1363         .read_iter =    ffs_epfile_read_iter,
1364         .release =      ffs_epfile_release,
1365         .unlocked_ioctl =       ffs_epfile_ioctl,
1366 #ifdef CONFIG_COMPAT
1367         .compat_ioctl = ffs_epfile_compat_ioctl,
1368 #endif
1369 };
1370
1371
1372 /* File system and super block operations ***********************************/
1373
1374 /*
1375  * Mounting the file system creates a controller file, used first for
1376  * function configuration then later for event monitoring.
1377  */
1378
1379 static struct inode *__must_check
1380 ffs_sb_make_inode(struct super_block *sb, void *data,
1381                   const struct file_operations *fops,
1382                   const struct inode_operations *iops,
1383                   struct ffs_file_perms *perms)
1384 {
1385         struct inode *inode;
1386
1387         ENTER();
1388
1389         inode = new_inode(sb);
1390
1391         if (likely(inode)) {
1392                 struct timespec64 ts = current_time(inode);
1393
1394                 inode->i_ino     = get_next_ino();
1395                 inode->i_mode    = perms->mode;
1396                 inode->i_uid     = perms->uid;
1397                 inode->i_gid     = perms->gid;
1398                 inode->i_atime   = ts;
1399                 inode->i_mtime   = ts;
1400                 inode->i_ctime   = ts;
1401                 inode->i_private = data;
1402                 if (fops)
1403                         inode->i_fop = fops;
1404                 if (iops)
1405                         inode->i_op  = iops;
1406         }
1407
1408         return inode;
1409 }
1410
1411 /* Create "regular" file */
1412 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1413                                         const char *name, void *data,
1414                                         const struct file_operations *fops)
1415 {
1416         struct ffs_data *ffs = sb->s_fs_info;
1417         struct dentry   *dentry;
1418         struct inode    *inode;
1419
1420         ENTER();
1421
1422         dentry = d_alloc_name(sb->s_root, name);
1423         if (unlikely(!dentry))
1424                 return NULL;
1425
1426         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1427         if (unlikely(!inode)) {
1428                 dput(dentry);
1429                 return NULL;
1430         }
1431
1432         d_add(dentry, inode);
1433         return dentry;
1434 }
1435
1436 /* Super block */
1437 static const struct super_operations ffs_sb_operations = {
1438         .statfs =       simple_statfs,
1439         .drop_inode =   generic_delete_inode,
1440 };
1441
1442 struct ffs_sb_fill_data {
1443         struct ffs_file_perms perms;
1444         umode_t root_mode;
1445         const char *dev_name;
1446         bool no_disconnect;
1447         struct ffs_data *ffs_data;
1448 };
1449
1450 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1451 {
1452         struct ffs_sb_fill_data *data = _data;
1453         struct inode    *inode;
1454         struct ffs_data *ffs = data->ffs_data;
1455
1456         ENTER();
1457
1458         ffs->sb              = sb;
1459         data->ffs_data       = NULL;
1460         sb->s_fs_info        = ffs;
1461         sb->s_blocksize      = PAGE_SIZE;
1462         sb->s_blocksize_bits = PAGE_SHIFT;
1463         sb->s_magic          = FUNCTIONFS_MAGIC;
1464         sb->s_op             = &ffs_sb_operations;
1465         sb->s_time_gran      = 1;
1466
1467         /* Root inode */
1468         data->perms.mode = data->root_mode;
1469         inode = ffs_sb_make_inode(sb, NULL,
1470                                   &simple_dir_operations,
1471                                   &simple_dir_inode_operations,
1472                                   &data->perms);
1473         sb->s_root = d_make_root(inode);
1474         if (unlikely(!sb->s_root))
1475                 return -ENOMEM;
1476
1477         /* EP0 file */
1478         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1479                                          &ffs_ep0_operations)))
1480                 return -ENOMEM;
1481
1482         return 0;
1483 }
1484
1485 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1486 {
1487         ENTER();
1488
1489         if (!opts || !*opts)
1490                 return 0;
1491
1492         for (;;) {
1493                 unsigned long value;
1494                 char *eq, *comma;
1495
1496                 /* Option limit */
1497                 comma = strchr(opts, ',');
1498                 if (comma)
1499                         *comma = 0;
1500
1501                 /* Value limit */
1502                 eq = strchr(opts, '=');
1503                 if (unlikely(!eq)) {
1504                         pr_err("'=' missing in %s\n", opts);
1505                         return -EINVAL;
1506                 }
1507                 *eq = 0;
1508
1509                 /* Parse value */
1510                 if (kstrtoul(eq + 1, 0, &value)) {
1511                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1512                         return -EINVAL;
1513                 }
1514
1515                 /* Interpret option */
1516                 switch (eq - opts) {
1517                 case 13:
1518                         if (!memcmp(opts, "no_disconnect", 13))
1519                                 data->no_disconnect = !!value;
1520                         else
1521                                 goto invalid;
1522                         break;
1523                 case 5:
1524                         if (!memcmp(opts, "rmode", 5))
1525                                 data->root_mode  = (value & 0555) | S_IFDIR;
1526                         else if (!memcmp(opts, "fmode", 5))
1527                                 data->perms.mode = (value & 0666) | S_IFREG;
1528                         else
1529                                 goto invalid;
1530                         break;
1531
1532                 case 4:
1533                         if (!memcmp(opts, "mode", 4)) {
1534                                 data->root_mode  = (value & 0555) | S_IFDIR;
1535                                 data->perms.mode = (value & 0666) | S_IFREG;
1536                         } else {
1537                                 goto invalid;
1538                         }
1539                         break;
1540
1541                 case 3:
1542                         if (!memcmp(opts, "uid", 3)) {
1543                                 data->perms.uid = make_kuid(current_user_ns(), value);
1544                                 if (!uid_valid(data->perms.uid)) {
1545                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1546                                         return -EINVAL;
1547                                 }
1548                         } else if (!memcmp(opts, "gid", 3)) {
1549                                 data->perms.gid = make_kgid(current_user_ns(), value);
1550                                 if (!gid_valid(data->perms.gid)) {
1551                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1552                                         return -EINVAL;
1553                                 }
1554                         } else {
1555                                 goto invalid;
1556                         }
1557                         break;
1558
1559                 default:
1560 invalid:
1561                         pr_err("%s: invalid option\n", opts);
1562                         return -EINVAL;
1563                 }
1564
1565                 /* Next iteration */
1566                 if (!comma)
1567                         break;
1568                 opts = comma + 1;
1569         }
1570
1571         return 0;
1572 }
1573
1574 /* "mount -t functionfs dev_name /dev/function" ends up here */
1575
1576 static struct dentry *
1577 ffs_fs_mount(struct file_system_type *t, int flags,
1578               const char *dev_name, void *opts)
1579 {
1580         struct ffs_sb_fill_data data = {
1581                 .perms = {
1582                         .mode = S_IFREG | 0600,
1583                         .uid = GLOBAL_ROOT_UID,
1584                         .gid = GLOBAL_ROOT_GID,
1585                 },
1586                 .root_mode = S_IFDIR | 0500,
1587                 .no_disconnect = false,
1588         };
1589         struct dentry *rv;
1590         int ret;
1591         void *ffs_dev;
1592         struct ffs_data *ffs;
1593
1594         ENTER();
1595
1596         ret = ffs_fs_parse_opts(&data, opts);
1597         if (unlikely(ret < 0))
1598                 return ERR_PTR(ret);
1599
1600         ffs = ffs_data_new(dev_name);
1601         if (unlikely(!ffs))
1602                 return ERR_PTR(-ENOMEM);
1603         ffs->file_perms = data.perms;
1604         ffs->no_disconnect = data.no_disconnect;
1605
1606         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1607         if (unlikely(!ffs->dev_name)) {
1608                 ffs_data_put(ffs);
1609                 return ERR_PTR(-ENOMEM);
1610         }
1611
1612         ffs_dev = ffs_acquire_dev(dev_name);
1613         if (IS_ERR(ffs_dev)) {
1614                 ffs_data_put(ffs);
1615                 return ERR_CAST(ffs_dev);
1616         }
1617         ffs->private_data = ffs_dev;
1618         data.ffs_data = ffs;
1619
1620         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1621         if (IS_ERR(rv) && data.ffs_data) {
1622                 ffs_release_dev(data.ffs_data);
1623                 ffs_data_put(data.ffs_data);
1624         }
1625         return rv;
1626 }
1627
1628 static void
1629 ffs_fs_kill_sb(struct super_block *sb)
1630 {
1631         ENTER();
1632
1633         kill_litter_super(sb);
1634         if (sb->s_fs_info) {
1635                 ffs_release_dev(sb->s_fs_info);
1636                 ffs_data_closed(sb->s_fs_info);
1637         }
1638 }
1639
1640 static struct file_system_type ffs_fs_type = {
1641         .owner          = THIS_MODULE,
1642         .name           = "functionfs",
1643         .mount          = ffs_fs_mount,
1644         .kill_sb        = ffs_fs_kill_sb,
1645 };
1646 MODULE_ALIAS_FS("functionfs");
1647
1648
1649 /* Driver's main init/cleanup functions *************************************/
1650
1651 static int functionfs_init(void)
1652 {
1653         int ret;
1654
1655         ENTER();
1656
1657         ret = register_filesystem(&ffs_fs_type);
1658         if (likely(!ret))
1659                 pr_info("file system registered\n");
1660         else
1661                 pr_err("failed registering file system (%d)\n", ret);
1662
1663         return ret;
1664 }
1665
1666 static void functionfs_cleanup(void)
1667 {
1668         ENTER();
1669
1670         pr_info("unloading\n");
1671         unregister_filesystem(&ffs_fs_type);
1672 }
1673
1674
1675 /* ffs_data and ffs_function construction and destruction code **************/
1676
1677 static void ffs_data_clear(struct ffs_data *ffs);
1678 static void ffs_data_reset(struct ffs_data *ffs);
1679
1680 static void ffs_data_get(struct ffs_data *ffs)
1681 {
1682         ENTER();
1683
1684         refcount_inc(&ffs->ref);
1685 }
1686
1687 static void ffs_data_opened(struct ffs_data *ffs)
1688 {
1689         ENTER();
1690
1691         refcount_inc(&ffs->ref);
1692         if (atomic_add_return(1, &ffs->opened) == 1 &&
1693                         ffs->state == FFS_DEACTIVATED) {
1694                 ffs->state = FFS_CLOSING;
1695                 ffs_data_reset(ffs);
1696         }
1697 }
1698
1699 static void ffs_data_put(struct ffs_data *ffs)
1700 {
1701         ENTER();
1702
1703         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1704                 pr_info("%s(): freeing\n", __func__);
1705                 ffs_data_clear(ffs);
1706                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1707                        waitqueue_active(&ffs->ep0req_completion.wait) ||
1708                        waitqueue_active(&ffs->wait));
1709                 destroy_workqueue(ffs->io_completion_wq);
1710                 kfree(ffs->dev_name);
1711                 kfree(ffs);
1712         }
1713 }
1714
1715 static void ffs_data_closed(struct ffs_data *ffs)
1716 {
1717         ENTER();
1718
1719         if (atomic_dec_and_test(&ffs->opened)) {
1720                 if (ffs->no_disconnect) {
1721                         ffs->state = FFS_DEACTIVATED;
1722                         if (ffs->epfiles) {
1723                                 ffs_epfiles_destroy(ffs->epfiles,
1724                                                    ffs->eps_count);
1725                                 ffs->epfiles = NULL;
1726                         }
1727                         if (ffs->setup_state == FFS_SETUP_PENDING)
1728                                 __ffs_ep0_stall(ffs);
1729                 } else {
1730                         ffs->state = FFS_CLOSING;
1731                         ffs_data_reset(ffs);
1732                 }
1733         }
1734         if (atomic_read(&ffs->opened) < 0) {
1735                 ffs->state = FFS_CLOSING;
1736                 ffs_data_reset(ffs);
1737         }
1738
1739         ffs_data_put(ffs);
1740 }
1741
1742 static struct ffs_data *ffs_data_new(const char *dev_name)
1743 {
1744         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1745         if (unlikely(!ffs))
1746                 return NULL;
1747
1748         ENTER();
1749
1750         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1751         if (!ffs->io_completion_wq) {
1752                 kfree(ffs);
1753                 return NULL;
1754         }
1755
1756         refcount_set(&ffs->ref, 1);
1757         atomic_set(&ffs->opened, 0);
1758         ffs->state = FFS_READ_DESCRIPTORS;
1759         mutex_init(&ffs->mutex);
1760         spin_lock_init(&ffs->eps_lock);
1761         init_waitqueue_head(&ffs->ev.waitq);
1762         init_waitqueue_head(&ffs->wait);
1763         init_completion(&ffs->ep0req_completion);
1764
1765         /* XXX REVISIT need to update it in some places, or do we? */
1766         ffs->ev.can_stall = 1;
1767
1768         return ffs;
1769 }
1770
1771 static void ffs_data_clear(struct ffs_data *ffs)
1772 {
1773         ENTER();
1774
1775         ffs_closed(ffs);
1776
1777         BUG_ON(ffs->gadget);
1778
1779         if (ffs->epfiles)
1780                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1781
1782         if (ffs->ffs_eventfd)
1783                 eventfd_ctx_put(ffs->ffs_eventfd);
1784
1785         kfree(ffs->raw_descs_data);
1786         kfree(ffs->raw_strings);
1787         kfree(ffs->stringtabs);
1788 }
1789
1790 static void ffs_data_reset(struct ffs_data *ffs)
1791 {
1792         ENTER();
1793
1794         ffs_data_clear(ffs);
1795
1796         ffs->epfiles = NULL;
1797         ffs->raw_descs_data = NULL;
1798         ffs->raw_descs = NULL;
1799         ffs->raw_strings = NULL;
1800         ffs->stringtabs = NULL;
1801
1802         ffs->raw_descs_length = 0;
1803         ffs->fs_descs_count = 0;
1804         ffs->hs_descs_count = 0;
1805         ffs->ss_descs_count = 0;
1806
1807         ffs->strings_count = 0;
1808         ffs->interfaces_count = 0;
1809         ffs->eps_count = 0;
1810
1811         ffs->ev.count = 0;
1812
1813         ffs->state = FFS_READ_DESCRIPTORS;
1814         ffs->setup_state = FFS_NO_SETUP;
1815         ffs->flags = 0;
1816 }
1817
1818
1819 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1820 {
1821         struct usb_gadget_strings **lang;
1822         int first_id;
1823
1824         ENTER();
1825
1826         if (WARN_ON(ffs->state != FFS_ACTIVE
1827                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1828                 return -EBADFD;
1829
1830         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1831         if (unlikely(first_id < 0))
1832                 return first_id;
1833
1834         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1835         if (unlikely(!ffs->ep0req))
1836                 return -ENOMEM;
1837         ffs->ep0req->complete = ffs_ep0_complete;
1838         ffs->ep0req->context = ffs;
1839
1840         lang = ffs->stringtabs;
1841         if (lang) {
1842                 for (; *lang; ++lang) {
1843                         struct usb_string *str = (*lang)->strings;
1844                         int id = first_id;
1845                         for (; str->s; ++id, ++str)
1846                                 str->id = id;
1847                 }
1848         }
1849
1850         ffs->gadget = cdev->gadget;
1851         ffs_data_get(ffs);
1852         return 0;
1853 }
1854
1855 static void functionfs_unbind(struct ffs_data *ffs)
1856 {
1857         ENTER();
1858
1859         if (!WARN_ON(!ffs->gadget)) {
1860                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1861                 ffs->ep0req = NULL;
1862                 ffs->gadget = NULL;
1863                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1864                 ffs_data_put(ffs);
1865         }
1866 }
1867
1868 static int ffs_epfiles_create(struct ffs_data *ffs)
1869 {
1870         struct ffs_epfile *epfile, *epfiles;
1871         unsigned i, count;
1872
1873         ENTER();
1874
1875         count = ffs->eps_count;
1876         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1877         if (!epfiles)
1878                 return -ENOMEM;
1879
1880         epfile = epfiles;
1881         for (i = 1; i <= count; ++i, ++epfile) {
1882                 epfile->ffs = ffs;
1883                 mutex_init(&epfile->mutex);
1884                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1885                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1886                 else
1887                         sprintf(epfile->name, "ep%u", i);
1888                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1889                                                  epfile,
1890                                                  &ffs_epfile_operations);
1891                 if (unlikely(!epfile->dentry)) {
1892                         ffs_epfiles_destroy(epfiles, i - 1);
1893                         return -ENOMEM;
1894                 }
1895         }
1896
1897         ffs->epfiles = epfiles;
1898         return 0;
1899 }
1900
1901 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1902 {
1903         struct ffs_epfile *epfile = epfiles;
1904
1905         ENTER();
1906
1907         for (; count; --count, ++epfile) {
1908                 BUG_ON(mutex_is_locked(&epfile->mutex));
1909                 if (epfile->dentry) {
1910                         d_delete(epfile->dentry);
1911                         dput(epfile->dentry);
1912                         epfile->dentry = NULL;
1913                 }
1914         }
1915
1916         kfree(epfiles);
1917 }
1918
1919 static void ffs_func_eps_disable(struct ffs_function *func)
1920 {
1921         struct ffs_ep *ep         = func->eps;
1922         struct ffs_epfile *epfile = func->ffs->epfiles;
1923         unsigned count            = func->ffs->eps_count;
1924         unsigned long flags;
1925
1926         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1927         while (count--) {
1928                 /* pending requests get nuked */
1929                 if (likely(ep->ep))
1930                         usb_ep_disable(ep->ep);
1931                 ++ep;
1932
1933                 if (epfile) {
1934                         epfile->ep = NULL;
1935                         __ffs_epfile_read_buffer_free(epfile);
1936                         ++epfile;
1937                 }
1938         }
1939         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1940 }
1941
1942 static int ffs_func_eps_enable(struct ffs_function *func)
1943 {
1944         struct ffs_data *ffs      = func->ffs;
1945         struct ffs_ep *ep         = func->eps;
1946         struct ffs_epfile *epfile = ffs->epfiles;
1947         unsigned count            = ffs->eps_count;
1948         unsigned long flags;
1949         int ret = 0;
1950
1951         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1952         while(count--) {
1953                 ep->ep->driver_data = ep;
1954
1955                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1956                 if (ret) {
1957                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1958                                         __func__, ep->ep->name, ret);
1959                         break;
1960                 }
1961
1962                 ret = usb_ep_enable(ep->ep);
1963                 if (likely(!ret)) {
1964                         epfile->ep = ep;
1965                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1966                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1967                 } else {
1968                         break;
1969                 }
1970
1971                 ++ep;
1972                 ++epfile;
1973         }
1974
1975         wake_up_interruptible(&ffs->wait);
1976         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1977
1978         return ret;
1979 }
1980
1981
1982 /* Parsing and building descriptors and strings *****************************/
1983
1984 /*
1985  * This validates if data pointed by data is a valid USB descriptor as
1986  * well as record how many interfaces, endpoints and strings are
1987  * required by given configuration.  Returns address after the
1988  * descriptor or NULL if data is invalid.
1989  */
1990
1991 enum ffs_entity_type {
1992         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1993 };
1994
1995 enum ffs_os_desc_type {
1996         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1997 };
1998
1999 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2000                                    u8 *valuep,
2001                                    struct usb_descriptor_header *desc,
2002                                    void *priv);
2003
2004 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2005                                     struct usb_os_desc_header *h, void *data,
2006                                     unsigned len, void *priv);
2007
2008 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2009                                            ffs_entity_callback entity,
2010                                            void *priv, int *current_class)
2011 {
2012         struct usb_descriptor_header *_ds = (void *)data;
2013         u8 length;
2014         int ret;
2015
2016         ENTER();
2017
2018         /* At least two bytes are required: length and type */
2019         if (len < 2) {
2020                 pr_vdebug("descriptor too short\n");
2021                 return -EINVAL;
2022         }
2023
2024         /* If we have at least as many bytes as the descriptor takes? */
2025         length = _ds->bLength;
2026         if (len < length) {
2027                 pr_vdebug("descriptor longer then available data\n");
2028                 return -EINVAL;
2029         }
2030
2031 #define __entity_check_INTERFACE(val)  1
2032 #define __entity_check_STRING(val)     (val)
2033 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2034 #define __entity(type, val) do {                                        \
2035                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2036                 if (unlikely(!__entity_check_ ##type(val))) {           \
2037                         pr_vdebug("invalid entity's value\n");          \
2038                         return -EINVAL;                                 \
2039                 }                                                       \
2040                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2041                 if (unlikely(ret < 0)) {                                \
2042                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2043                                  (val), ret);                           \
2044                         return ret;                                     \
2045                 }                                                       \
2046         } while (0)
2047
2048         /* Parse descriptor depending on type. */
2049         switch (_ds->bDescriptorType) {
2050         case USB_DT_DEVICE:
2051         case USB_DT_CONFIG:
2052         case USB_DT_STRING:
2053         case USB_DT_DEVICE_QUALIFIER:
2054                 /* function can't have any of those */
2055                 pr_vdebug("descriptor reserved for gadget: %d\n",
2056                       _ds->bDescriptorType);
2057                 return -EINVAL;
2058
2059         case USB_DT_INTERFACE: {
2060                 struct usb_interface_descriptor *ds = (void *)_ds;
2061                 pr_vdebug("interface descriptor\n");
2062                 if (length != sizeof *ds)
2063                         goto inv_length;
2064
2065                 __entity(INTERFACE, ds->bInterfaceNumber);
2066                 if (ds->iInterface)
2067                         __entity(STRING, ds->iInterface);
2068                 *current_class = ds->bInterfaceClass;
2069         }
2070                 break;
2071
2072         case USB_DT_ENDPOINT: {
2073                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2074                 pr_vdebug("endpoint descriptor\n");
2075                 if (length != USB_DT_ENDPOINT_SIZE &&
2076                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2077                         goto inv_length;
2078                 __entity(ENDPOINT, ds->bEndpointAddress);
2079         }
2080                 break;
2081
2082         case USB_TYPE_CLASS | 0x01:
2083                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2084                         pr_vdebug("hid descriptor\n");
2085                         if (length != sizeof(struct hid_descriptor))
2086                                 goto inv_length;
2087                         break;
2088                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2089                         pr_vdebug("ccid descriptor\n");
2090                         if (length != sizeof(struct ccid_descriptor))
2091                                 goto inv_length;
2092                         break;
2093                 } else {
2094                         pr_vdebug("unknown descriptor: %d for class %d\n",
2095                               _ds->bDescriptorType, *current_class);
2096                         return -EINVAL;
2097                 }
2098
2099         case USB_DT_OTG:
2100                 if (length != sizeof(struct usb_otg_descriptor))
2101                         goto inv_length;
2102                 break;
2103
2104         case USB_DT_INTERFACE_ASSOCIATION: {
2105                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2106                 pr_vdebug("interface association descriptor\n");
2107                 if (length != sizeof *ds)
2108                         goto inv_length;
2109                 if (ds->iFunction)
2110                         __entity(STRING, ds->iFunction);
2111         }
2112                 break;
2113
2114         case USB_DT_SS_ENDPOINT_COMP:
2115                 pr_vdebug("EP SS companion descriptor\n");
2116                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2117                         goto inv_length;
2118                 break;
2119
2120         case USB_DT_OTHER_SPEED_CONFIG:
2121         case USB_DT_INTERFACE_POWER:
2122         case USB_DT_DEBUG:
2123         case USB_DT_SECURITY:
2124         case USB_DT_CS_RADIO_CONTROL:
2125                 /* TODO */
2126                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2127                 return -EINVAL;
2128
2129         default:
2130                 /* We should never be here */
2131                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2132                 return -EINVAL;
2133
2134 inv_length:
2135                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2136                           _ds->bLength, _ds->bDescriptorType);
2137                 return -EINVAL;
2138         }
2139
2140 #undef __entity
2141 #undef __entity_check_DESCRIPTOR
2142 #undef __entity_check_INTERFACE
2143 #undef __entity_check_STRING
2144 #undef __entity_check_ENDPOINT
2145
2146         return length;
2147 }
2148
2149 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2150                                      ffs_entity_callback entity, void *priv)
2151 {
2152         const unsigned _len = len;
2153         unsigned long num = 0;
2154         int current_class = -1;
2155
2156         ENTER();
2157
2158         for (;;) {
2159                 int ret;
2160
2161                 if (num == count)
2162                         data = NULL;
2163
2164                 /* Record "descriptor" entity */
2165                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2166                 if (unlikely(ret < 0)) {
2167                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2168                                  num, ret);
2169                         return ret;
2170                 }
2171
2172                 if (!data)
2173                         return _len - len;
2174
2175                 ret = ffs_do_single_desc(data, len, entity, priv,
2176                         &current_class);
2177                 if (unlikely(ret < 0)) {
2178                         pr_debug("%s returns %d\n", __func__, ret);
2179                         return ret;
2180                 }
2181
2182                 len -= ret;
2183                 data += ret;
2184                 ++num;
2185         }
2186 }
2187
2188 static int __ffs_data_do_entity(enum ffs_entity_type type,
2189                                 u8 *valuep, struct usb_descriptor_header *desc,
2190                                 void *priv)
2191 {
2192         struct ffs_desc_helper *helper = priv;
2193         struct usb_endpoint_descriptor *d;
2194
2195         ENTER();
2196
2197         switch (type) {
2198         case FFS_DESCRIPTOR:
2199                 break;
2200
2201         case FFS_INTERFACE:
2202                 /*
2203                  * Interfaces are indexed from zero so if we
2204                  * encountered interface "n" then there are at least
2205                  * "n+1" interfaces.
2206                  */
2207                 if (*valuep >= helper->interfaces_count)
2208                         helper->interfaces_count = *valuep + 1;
2209                 break;
2210
2211         case FFS_STRING:
2212                 /*
2213                  * Strings are indexed from 1 (0 is reserved
2214                  * for languages list)
2215                  */
2216                 if (*valuep > helper->ffs->strings_count)
2217                         helper->ffs->strings_count = *valuep;
2218                 break;
2219
2220         case FFS_ENDPOINT:
2221                 d = (void *)desc;
2222                 helper->eps_count++;
2223                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2224                         return -EINVAL;
2225                 /* Check if descriptors for any speed were already parsed */
2226                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2227                         helper->ffs->eps_addrmap[helper->eps_count] =
2228                                 d->bEndpointAddress;
2229                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2230                                 d->bEndpointAddress)
2231                         return -EINVAL;
2232                 break;
2233         }
2234
2235         return 0;
2236 }
2237
2238 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2239                                    struct usb_os_desc_header *desc)
2240 {
2241         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2242         u16 w_index = le16_to_cpu(desc->wIndex);
2243
2244         if (bcd_version != 1) {
2245                 pr_vdebug("unsupported os descriptors version: %d",
2246                           bcd_version);
2247                 return -EINVAL;
2248         }
2249         switch (w_index) {
2250         case 0x4:
2251                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2252                 break;
2253         case 0x5:
2254                 *next_type = FFS_OS_DESC_EXT_PROP;
2255                 break;
2256         default:
2257                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2258                 return -EINVAL;
2259         }
2260
2261         return sizeof(*desc);
2262 }
2263
2264 /*
2265  * Process all extended compatibility/extended property descriptors
2266  * of a feature descriptor
2267  */
2268 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2269                                               enum ffs_os_desc_type type,
2270                                               u16 feature_count,
2271                                               ffs_os_desc_callback entity,
2272                                               void *priv,
2273                                               struct usb_os_desc_header *h)
2274 {
2275         int ret;
2276         const unsigned _len = len;
2277
2278         ENTER();
2279
2280         /* loop over all ext compat/ext prop descriptors */
2281         while (feature_count--) {
2282                 ret = entity(type, h, data, len, priv);
2283                 if (unlikely(ret < 0)) {
2284                         pr_debug("bad OS descriptor, type: %d\n", type);
2285                         return ret;
2286                 }
2287                 data += ret;
2288                 len -= ret;
2289         }
2290         return _len - len;
2291 }
2292
2293 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2294 static int __must_check ffs_do_os_descs(unsigned count,
2295                                         char *data, unsigned len,
2296                                         ffs_os_desc_callback entity, void *priv)
2297 {
2298         const unsigned _len = len;
2299         unsigned long num = 0;
2300
2301         ENTER();
2302
2303         for (num = 0; num < count; ++num) {
2304                 int ret;
2305                 enum ffs_os_desc_type type;
2306                 u16 feature_count;
2307                 struct usb_os_desc_header *desc = (void *)data;
2308
2309                 if (len < sizeof(*desc))
2310                         return -EINVAL;
2311
2312                 /*
2313                  * Record "descriptor" entity.
2314                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2315                  * Move the data pointer to the beginning of extended
2316                  * compatibilities proper or extended properties proper
2317                  * portions of the data
2318                  */
2319                 if (le32_to_cpu(desc->dwLength) > len)
2320                         return -EINVAL;
2321
2322                 ret = __ffs_do_os_desc_header(&type, desc);
2323                 if (unlikely(ret < 0)) {
2324                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2325                                  num, ret);
2326                         return ret;
2327                 }
2328                 /*
2329                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2330                  */
2331                 feature_count = le16_to_cpu(desc->wCount);
2332                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2333                     (feature_count > 255 || desc->Reserved))
2334                                 return -EINVAL;
2335                 len -= ret;
2336                 data += ret;
2337
2338                 /*
2339                  * Process all function/property descriptors
2340                  * of this Feature Descriptor
2341                  */
2342                 ret = ffs_do_single_os_desc(data, len, type,
2343                                             feature_count, entity, priv, desc);
2344                 if (unlikely(ret < 0)) {
2345                         pr_debug("%s returns %d\n", __func__, ret);
2346                         return ret;
2347                 }
2348
2349                 len -= ret;
2350                 data += ret;
2351         }
2352         return _len - len;
2353 }
2354
2355 /**
2356  * Validate contents of the buffer from userspace related to OS descriptors.
2357  */
2358 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2359                                  struct usb_os_desc_header *h, void *data,
2360                                  unsigned len, void *priv)
2361 {
2362         struct ffs_data *ffs = priv;
2363         u8 length;
2364
2365         ENTER();
2366
2367         switch (type) {
2368         case FFS_OS_DESC_EXT_COMPAT: {
2369                 struct usb_ext_compat_desc *d = data;
2370                 int i;
2371
2372                 if (len < sizeof(*d) ||
2373                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2374                         return -EINVAL;
2375                 if (d->Reserved1 != 1) {
2376                         /*
2377                          * According to the spec, Reserved1 must be set to 1
2378                          * but older kernels incorrectly rejected non-zero
2379                          * values.  We fix it here to avoid returning EINVAL
2380                          * in response to values we used to accept.
2381                          */
2382                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2383                         d->Reserved1 = 1;
2384                 }
2385                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2386                         if (d->Reserved2[i])
2387                                 return -EINVAL;
2388
2389                 length = sizeof(struct usb_ext_compat_desc);
2390         }
2391                 break;
2392         case FFS_OS_DESC_EXT_PROP: {
2393                 struct usb_ext_prop_desc *d = data;
2394                 u32 type, pdl;
2395                 u16 pnl;
2396
2397                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2398                         return -EINVAL;
2399                 length = le32_to_cpu(d->dwSize);
2400                 if (len < length)
2401                         return -EINVAL;
2402                 type = le32_to_cpu(d->dwPropertyDataType);
2403                 if (type < USB_EXT_PROP_UNICODE ||
2404                     type > USB_EXT_PROP_UNICODE_MULTI) {
2405                         pr_vdebug("unsupported os descriptor property type: %d",
2406                                   type);
2407                         return -EINVAL;
2408                 }
2409                 pnl = le16_to_cpu(d->wPropertyNameLength);
2410                 if (length < 14 + pnl) {
2411                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2412                                   length, pnl, type);
2413                         return -EINVAL;
2414                 }
2415                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2416                 if (length != 14 + pnl + pdl) {
2417                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2418                                   length, pnl, pdl, type);
2419                         return -EINVAL;
2420                 }
2421                 ++ffs->ms_os_descs_ext_prop_count;
2422                 /* property name reported to the host as "WCHAR"s */
2423                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2424                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2425         }
2426                 break;
2427         default:
2428                 pr_vdebug("unknown descriptor: %d\n", type);
2429                 return -EINVAL;
2430         }
2431         return length;
2432 }
2433
2434 static int __ffs_data_got_descs(struct ffs_data *ffs,
2435                                 char *const _data, size_t len)
2436 {
2437         char *data = _data, *raw_descs;
2438         unsigned os_descs_count = 0, counts[3], flags;
2439         int ret = -EINVAL, i;
2440         struct ffs_desc_helper helper;
2441
2442         ENTER();
2443
2444         if (get_unaligned_le32(data + 4) != len)
2445                 goto error;
2446
2447         switch (get_unaligned_le32(data)) {
2448         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2449                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2450                 data += 8;
2451                 len  -= 8;
2452                 break;
2453         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2454                 flags = get_unaligned_le32(data + 8);
2455                 ffs->user_flags = flags;
2456                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2457                               FUNCTIONFS_HAS_HS_DESC |
2458                               FUNCTIONFS_HAS_SS_DESC |
2459                               FUNCTIONFS_HAS_MS_OS_DESC |
2460                               FUNCTIONFS_VIRTUAL_ADDR |
2461                               FUNCTIONFS_EVENTFD |
2462                               FUNCTIONFS_ALL_CTRL_RECIP |
2463                               FUNCTIONFS_CONFIG0_SETUP)) {
2464                         ret = -ENOSYS;
2465                         goto error;
2466                 }
2467                 data += 12;
2468                 len  -= 12;
2469                 break;
2470         default:
2471                 goto error;
2472         }
2473
2474         if (flags & FUNCTIONFS_EVENTFD) {
2475                 if (len < 4)
2476                         goto error;
2477                 ffs->ffs_eventfd =
2478                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2479                 if (IS_ERR(ffs->ffs_eventfd)) {
2480                         ret = PTR_ERR(ffs->ffs_eventfd);
2481                         ffs->ffs_eventfd = NULL;
2482                         goto error;
2483                 }
2484                 data += 4;
2485                 len  -= 4;
2486         }
2487
2488         /* Read fs_count, hs_count and ss_count (if present) */
2489         for (i = 0; i < 3; ++i) {
2490                 if (!(flags & (1 << i))) {
2491                         counts[i] = 0;
2492                 } else if (len < 4) {
2493                         goto error;
2494                 } else {
2495                         counts[i] = get_unaligned_le32(data);
2496                         data += 4;
2497                         len  -= 4;
2498                 }
2499         }
2500         if (flags & (1 << i)) {
2501                 if (len < 4) {
2502                         goto error;
2503                 }
2504                 os_descs_count = get_unaligned_le32(data);
2505                 data += 4;
2506                 len -= 4;
2507         };
2508
2509         /* Read descriptors */
2510         raw_descs = data;
2511         helper.ffs = ffs;
2512         for (i = 0; i < 3; ++i) {
2513                 if (!counts[i])
2514                         continue;
2515                 helper.interfaces_count = 0;
2516                 helper.eps_count = 0;
2517                 ret = ffs_do_descs(counts[i], data, len,
2518                                    __ffs_data_do_entity, &helper);
2519                 if (ret < 0)
2520                         goto error;
2521                 if (!ffs->eps_count && !ffs->interfaces_count) {
2522                         ffs->eps_count = helper.eps_count;
2523                         ffs->interfaces_count = helper.interfaces_count;
2524                 } else {
2525                         if (ffs->eps_count != helper.eps_count) {
2526                                 ret = -EINVAL;
2527                                 goto error;
2528                         }
2529                         if (ffs->interfaces_count != helper.interfaces_count) {
2530                                 ret = -EINVAL;
2531                                 goto error;
2532                         }
2533                 }
2534                 data += ret;
2535                 len  -= ret;
2536         }
2537         if (os_descs_count) {
2538                 ret = ffs_do_os_descs(os_descs_count, data, len,
2539                                       __ffs_data_do_os_desc, ffs);
2540                 if (ret < 0)
2541                         goto error;
2542                 data += ret;
2543                 len -= ret;
2544         }
2545
2546         if (raw_descs == data || len) {
2547                 ret = -EINVAL;
2548                 goto error;
2549         }
2550
2551         ffs->raw_descs_data     = _data;
2552         ffs->raw_descs          = raw_descs;
2553         ffs->raw_descs_length   = data - raw_descs;
2554         ffs->fs_descs_count     = counts[0];
2555         ffs->hs_descs_count     = counts[1];
2556         ffs->ss_descs_count     = counts[2];
2557         ffs->ms_os_descs_count  = os_descs_count;
2558
2559         return 0;
2560
2561 error:
2562         kfree(_data);
2563         return ret;
2564 }
2565
2566 static int __ffs_data_got_strings(struct ffs_data *ffs,
2567                                   char *const _data, size_t len)
2568 {
2569         u32 str_count, needed_count, lang_count;
2570         struct usb_gadget_strings **stringtabs, *t;
2571         const char *data = _data;
2572         struct usb_string *s;
2573
2574         ENTER();
2575
2576         if (unlikely(len < 16 ||
2577                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2578                      get_unaligned_le32(data + 4) != len))
2579                 goto error;
2580         str_count  = get_unaligned_le32(data + 8);
2581         lang_count = get_unaligned_le32(data + 12);
2582
2583         /* if one is zero the other must be zero */
2584         if (unlikely(!str_count != !lang_count))
2585                 goto error;
2586
2587         /* Do we have at least as many strings as descriptors need? */
2588         needed_count = ffs->strings_count;
2589         if (unlikely(str_count < needed_count))
2590                 goto error;
2591
2592         /*
2593          * If we don't need any strings just return and free all
2594          * memory.
2595          */
2596         if (!needed_count) {
2597                 kfree(_data);
2598                 return 0;
2599         }
2600
2601         /* Allocate everything in one chunk so there's less maintenance. */
2602         {
2603                 unsigned i = 0;
2604                 vla_group(d);
2605                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2606                         lang_count + 1);
2607                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2608                 vla_item(d, struct usb_string, strings,
2609                         lang_count*(needed_count+1));
2610
2611                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2612
2613                 if (unlikely(!vlabuf)) {
2614                         kfree(_data);
2615                         return -ENOMEM;
2616                 }
2617
2618                 /* Initialize the VLA pointers */
2619                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2620                 t = vla_ptr(vlabuf, d, stringtab);
2621                 i = lang_count;
2622                 do {
2623                         *stringtabs++ = t++;
2624                 } while (--i);
2625                 *stringtabs = NULL;
2626
2627                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2628                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2629                 t = vla_ptr(vlabuf, d, stringtab);
2630                 s = vla_ptr(vlabuf, d, strings);
2631         }
2632
2633         /* For each language */
2634         data += 16;
2635         len -= 16;
2636
2637         do { /* lang_count > 0 so we can use do-while */
2638                 unsigned needed = needed_count;
2639
2640                 if (unlikely(len < 3))
2641                         goto error_free;
2642                 t->language = get_unaligned_le16(data);
2643                 t->strings  = s;
2644                 ++t;
2645
2646                 data += 2;
2647                 len -= 2;
2648
2649                 /* For each string */
2650                 do { /* str_count > 0 so we can use do-while */
2651                         size_t length = strnlen(data, len);
2652
2653                         if (unlikely(length == len))
2654                                 goto error_free;
2655
2656                         /*
2657                          * User may provide more strings then we need,
2658                          * if that's the case we simply ignore the
2659                          * rest
2660                          */
2661                         if (likely(needed)) {
2662                                 /*
2663                                  * s->id will be set while adding
2664                                  * function to configuration so for
2665                                  * now just leave garbage here.
2666                                  */
2667                                 s->s = data;
2668                                 --needed;
2669                                 ++s;
2670                         }
2671
2672                         data += length + 1;
2673                         len -= length + 1;
2674                 } while (--str_count);
2675
2676                 s->id = 0;   /* terminator */
2677                 s->s = NULL;
2678                 ++s;
2679
2680         } while (--lang_count);
2681
2682         /* Some garbage left? */
2683         if (unlikely(len))
2684                 goto error_free;
2685
2686         /* Done! */
2687         ffs->stringtabs = stringtabs;
2688         ffs->raw_strings = _data;
2689
2690         return 0;
2691
2692 error_free:
2693         kfree(stringtabs);
2694 error:
2695         kfree(_data);
2696         return -EINVAL;
2697 }
2698
2699
2700 /* Events handling and management *******************************************/
2701
2702 static void __ffs_event_add(struct ffs_data *ffs,
2703                             enum usb_functionfs_event_type type)
2704 {
2705         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2706         int neg = 0;
2707
2708         /*
2709          * Abort any unhandled setup
2710          *
2711          * We do not need to worry about some cmpxchg() changing value
2712          * of ffs->setup_state without holding the lock because when
2713          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2714          * the source does nothing.
2715          */
2716         if (ffs->setup_state == FFS_SETUP_PENDING)
2717                 ffs->setup_state = FFS_SETUP_CANCELLED;
2718
2719         /*
2720          * Logic of this function guarantees that there are at most four pending
2721          * evens on ffs->ev.types queue.  This is important because the queue
2722          * has space for four elements only and __ffs_ep0_read_events function
2723          * depends on that limit as well.  If more event types are added, those
2724          * limits have to be revisited or guaranteed to still hold.
2725          */
2726         switch (type) {
2727         case FUNCTIONFS_RESUME:
2728                 rem_type2 = FUNCTIONFS_SUSPEND;
2729                 /* FALL THROUGH */
2730         case FUNCTIONFS_SUSPEND:
2731         case FUNCTIONFS_SETUP:
2732                 rem_type1 = type;
2733                 /* Discard all similar events */
2734                 break;
2735
2736         case FUNCTIONFS_BIND:
2737         case FUNCTIONFS_UNBIND:
2738         case FUNCTIONFS_DISABLE:
2739         case FUNCTIONFS_ENABLE:
2740                 /* Discard everything other then power management. */
2741                 rem_type1 = FUNCTIONFS_SUSPEND;
2742                 rem_type2 = FUNCTIONFS_RESUME;
2743                 neg = 1;
2744                 break;
2745
2746         default:
2747                 WARN(1, "%d: unknown event, this should not happen\n", type);
2748                 return;
2749         }
2750
2751         {
2752                 u8 *ev  = ffs->ev.types, *out = ev;
2753                 unsigned n = ffs->ev.count;
2754                 for (; n; --n, ++ev)
2755                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2756                                 *out++ = *ev;
2757                         else
2758                                 pr_vdebug("purging event %d\n", *ev);
2759                 ffs->ev.count = out - ffs->ev.types;
2760         }
2761
2762         pr_vdebug("adding event %d\n", type);
2763         ffs->ev.types[ffs->ev.count++] = type;
2764         wake_up_locked(&ffs->ev.waitq);
2765         if (ffs->ffs_eventfd)
2766                 eventfd_signal(ffs->ffs_eventfd, 1);
2767 }
2768
2769 static void ffs_event_add(struct ffs_data *ffs,
2770                           enum usb_functionfs_event_type type)
2771 {
2772         unsigned long flags;
2773         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2774         __ffs_event_add(ffs, type);
2775         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2776 }
2777
2778 /* Bind/unbind USB function hooks *******************************************/
2779
2780 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2781 {
2782         int i;
2783
2784         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2785                 if (ffs->eps_addrmap[i] == endpoint_address)
2786                         return i;
2787         return -ENOENT;
2788 }
2789
2790 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2791                                     struct usb_descriptor_header *desc,
2792                                     void *priv)
2793 {
2794         struct usb_endpoint_descriptor *ds = (void *)desc;
2795         struct ffs_function *func = priv;
2796         struct ffs_ep *ffs_ep;
2797         unsigned ep_desc_id;
2798         int idx;
2799         static const char *speed_names[] = { "full", "high", "super" };
2800
2801         if (type != FFS_DESCRIPTOR)
2802                 return 0;
2803
2804         /*
2805          * If ss_descriptors is not NULL, we are reading super speed
2806          * descriptors; if hs_descriptors is not NULL, we are reading high
2807          * speed descriptors; otherwise, we are reading full speed
2808          * descriptors.
2809          */
2810         if (func->function.ss_descriptors) {
2811                 ep_desc_id = 2;
2812                 func->function.ss_descriptors[(long)valuep] = desc;
2813         } else if (func->function.hs_descriptors) {
2814                 ep_desc_id = 1;
2815                 func->function.hs_descriptors[(long)valuep] = desc;
2816         } else {
2817                 ep_desc_id = 0;
2818                 func->function.fs_descriptors[(long)valuep]    = desc;
2819         }
2820
2821         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2822                 return 0;
2823
2824         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2825         if (idx < 0)
2826                 return idx;
2827
2828         ffs_ep = func->eps + idx;
2829
2830         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2831                 pr_err("two %sspeed descriptors for EP %d\n",
2832                           speed_names[ep_desc_id],
2833                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2834                 return -EINVAL;
2835         }
2836         ffs_ep->descs[ep_desc_id] = ds;
2837
2838         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2839         if (ffs_ep->ep) {
2840                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2841                 if (!ds->wMaxPacketSize)
2842                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2843         } else {
2844                 struct usb_request *req;
2845                 struct usb_ep *ep;
2846                 u8 bEndpointAddress;
2847
2848                 /*
2849                  * We back up bEndpointAddress because autoconfig overwrites
2850                  * it with physical endpoint address.
2851                  */
2852                 bEndpointAddress = ds->bEndpointAddress;
2853                 pr_vdebug("autoconfig\n");
2854                 ep = usb_ep_autoconfig(func->gadget, ds);
2855                 if (unlikely(!ep))
2856                         return -ENOTSUPP;
2857                 ep->driver_data = func->eps + idx;
2858
2859                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2860                 if (unlikely(!req))
2861                         return -ENOMEM;
2862
2863                 ffs_ep->ep  = ep;
2864                 ffs_ep->req = req;
2865                 func->eps_revmap[ds->bEndpointAddress &
2866                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2867                 /*
2868                  * If we use virtual address mapping, we restore
2869                  * original bEndpointAddress value.
2870                  */
2871                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2872                         ds->bEndpointAddress = bEndpointAddress;
2873         }
2874         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2875
2876         return 0;
2877 }
2878
2879 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2880                                    struct usb_descriptor_header *desc,
2881                                    void *priv)
2882 {
2883         struct ffs_function *func = priv;
2884         unsigned idx;
2885         u8 newValue;
2886
2887         switch (type) {
2888         default:
2889         case FFS_DESCRIPTOR:
2890                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2891                 return 0;
2892
2893         case FFS_INTERFACE:
2894                 idx = *valuep;
2895                 if (func->interfaces_nums[idx] < 0) {
2896                         int id = usb_interface_id(func->conf, &func->function);
2897                         if (unlikely(id < 0))
2898                                 return id;
2899                         func->interfaces_nums[idx] = id;
2900                 }
2901                 newValue = func->interfaces_nums[idx];
2902                 break;
2903
2904         case FFS_STRING:
2905                 /* String' IDs are allocated when fsf_data is bound to cdev */
2906                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2907                 break;
2908
2909         case FFS_ENDPOINT:
2910                 /*
2911                  * USB_DT_ENDPOINT are handled in
2912                  * __ffs_func_bind_do_descs().
2913                  */
2914                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2915                         return 0;
2916
2917                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2918                 if (unlikely(!func->eps[idx].ep))
2919                         return -EINVAL;
2920
2921                 {
2922                         struct usb_endpoint_descriptor **descs;
2923                         descs = func->eps[idx].descs;
2924                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2925                 }
2926                 break;
2927         }
2928
2929         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2930         *valuep = newValue;
2931         return 0;
2932 }
2933
2934 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2935                                       struct usb_os_desc_header *h, void *data,
2936                                       unsigned len, void *priv)
2937 {
2938         struct ffs_function *func = priv;
2939         u8 length = 0;
2940
2941         switch (type) {
2942         case FFS_OS_DESC_EXT_COMPAT: {
2943                 struct usb_ext_compat_desc *desc = data;
2944                 struct usb_os_desc_table *t;
2945
2946                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2947                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2948                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2949                        ARRAY_SIZE(desc->CompatibleID) +
2950                        ARRAY_SIZE(desc->SubCompatibleID));
2951                 length = sizeof(*desc);
2952         }
2953                 break;
2954         case FFS_OS_DESC_EXT_PROP: {
2955                 struct usb_ext_prop_desc *desc = data;
2956                 struct usb_os_desc_table *t;
2957                 struct usb_os_desc_ext_prop *ext_prop;
2958                 char *ext_prop_name;
2959                 char *ext_prop_data;
2960
2961                 t = &func->function.os_desc_table[h->interface];
2962                 t->if_id = func->interfaces_nums[h->interface];
2963
2964                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2965                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2966
2967                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2968                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2969                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2970                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2971                 length = ext_prop->name_len + ext_prop->data_len + 14;
2972
2973                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2974                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2975                         ext_prop->name_len;
2976
2977                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2978                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2979                         ext_prop->data_len;
2980                 memcpy(ext_prop_data,
2981                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2982                        ext_prop->data_len);
2983                 /* unicode data reported to the host as "WCHAR"s */
2984                 switch (ext_prop->type) {
2985                 case USB_EXT_PROP_UNICODE:
2986                 case USB_EXT_PROP_UNICODE_ENV:
2987                 case USB_EXT_PROP_UNICODE_LINK:
2988                 case USB_EXT_PROP_UNICODE_MULTI:
2989                         ext_prop->data_len *= 2;
2990                         break;
2991                 }
2992                 ext_prop->data = ext_prop_data;
2993
2994                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2995                        ext_prop->name_len);
2996                 /* property name reported to the host as "WCHAR"s */
2997                 ext_prop->name_len *= 2;
2998                 ext_prop->name = ext_prop_name;
2999
3000                 t->os_desc->ext_prop_len +=
3001                         ext_prop->name_len + ext_prop->data_len + 14;
3002                 ++t->os_desc->ext_prop_count;
3003                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3004         }
3005                 break;
3006         default:
3007                 pr_vdebug("unknown descriptor: %d\n", type);
3008         }
3009
3010         return length;
3011 }
3012
3013 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3014                                                 struct usb_configuration *c)
3015 {
3016         struct ffs_function *func = ffs_func_from_usb(f);
3017         struct f_fs_opts *ffs_opts =
3018                 container_of(f->fi, struct f_fs_opts, func_inst);
3019         int ret;
3020
3021         ENTER();
3022
3023         /*
3024          * Legacy gadget triggers binding in functionfs_ready_callback,
3025          * which already uses locking; taking the same lock here would
3026          * cause a deadlock.
3027          *
3028          * Configfs-enabled gadgets however do need ffs_dev_lock.
3029          */
3030         if (!ffs_opts->no_configfs)
3031                 ffs_dev_lock();
3032         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3033         func->ffs = ffs_opts->dev->ffs_data;
3034         if (!ffs_opts->no_configfs)
3035                 ffs_dev_unlock();
3036         if (ret)
3037                 return ERR_PTR(ret);
3038
3039         func->conf = c;
3040         func->gadget = c->cdev->gadget;
3041
3042         /*
3043          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3044          * configurations are bound in sequence with list_for_each_entry,
3045          * in each configuration its functions are bound in sequence
3046          * with list_for_each_entry, so we assume no race condition
3047          * with regard to ffs_opts->bound access
3048          */
3049         if (!ffs_opts->refcnt) {
3050                 ret = functionfs_bind(func->ffs, c->cdev);
3051                 if (ret)
3052                         return ERR_PTR(ret);
3053         }
3054         ffs_opts->refcnt++;
3055         func->function.strings = func->ffs->stringtabs;
3056
3057         return ffs_opts;
3058 }
3059
3060 static int _ffs_func_bind(struct usb_configuration *c,
3061                           struct usb_function *f)
3062 {
3063         struct ffs_function *func = ffs_func_from_usb(f);
3064         struct ffs_data *ffs = func->ffs;
3065
3066         const int full = !!func->ffs->fs_descs_count;
3067         const int high = !!func->ffs->hs_descs_count;
3068         const int super = !!func->ffs->ss_descs_count;
3069
3070         int fs_len, hs_len, ss_len, ret, i;
3071         struct ffs_ep *eps_ptr;
3072
3073         /* Make it a single chunk, less management later on */
3074         vla_group(d);
3075         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3076         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3077                 full ? ffs->fs_descs_count + 1 : 0);
3078         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3079                 high ? ffs->hs_descs_count + 1 : 0);
3080         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3081                 super ? ffs->ss_descs_count + 1 : 0);
3082         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3083         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3084                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3085         vla_item_with_sz(d, char[16], ext_compat,
3086                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3087         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3088                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3089         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3090                          ffs->ms_os_descs_ext_prop_count);
3091         vla_item_with_sz(d, char, ext_prop_name,
3092                          ffs->ms_os_descs_ext_prop_name_len);
3093         vla_item_with_sz(d, char, ext_prop_data,
3094                          ffs->ms_os_descs_ext_prop_data_len);
3095         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3096         char *vlabuf;
3097
3098         ENTER();
3099
3100         /* Has descriptors only for speeds gadget does not support */
3101         if (unlikely(!(full | high | super)))
3102                 return -ENOTSUPP;
3103
3104         /* Allocate a single chunk, less management later on */
3105         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3106         if (unlikely(!vlabuf))
3107                 return -ENOMEM;
3108
3109         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3110         ffs->ms_os_descs_ext_prop_name_avail =
3111                 vla_ptr(vlabuf, d, ext_prop_name);
3112         ffs->ms_os_descs_ext_prop_data_avail =
3113                 vla_ptr(vlabuf, d, ext_prop_data);
3114
3115         /* Copy descriptors  */
3116         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3117                ffs->raw_descs_length);
3118
3119         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3120         eps_ptr = vla_ptr(vlabuf, d, eps);
3121         for (i = 0; i < ffs->eps_count; i++)
3122                 eps_ptr[i].num = -1;
3123
3124         /* Save pointers
3125          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3126         */
3127         func->eps             = vla_ptr(vlabuf, d, eps);
3128         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3129
3130         /*
3131          * Go through all the endpoint descriptors and allocate
3132          * endpoints first, so that later we can rewrite the endpoint
3133          * numbers without worrying that it may be described later on.
3134          */
3135         if (likely(full)) {
3136                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3137                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3138                                       vla_ptr(vlabuf, d, raw_descs),
3139                                       d_raw_descs__sz,
3140                                       __ffs_func_bind_do_descs, func);
3141                 if (unlikely(fs_len < 0)) {
3142                         ret = fs_len;
3143                         goto error;
3144                 }
3145         } else {
3146                 fs_len = 0;
3147         }
3148
3149         if (likely(high)) {
3150                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3151                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3152                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3153                                       d_raw_descs__sz - fs_len,
3154                                       __ffs_func_bind_do_descs, func);
3155                 if (unlikely(hs_len < 0)) {
3156                         ret = hs_len;
3157                         goto error;
3158                 }
3159         } else {
3160                 hs_len = 0;
3161         }
3162
3163         if (likely(super)) {
3164                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3165                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3166                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3167                                 d_raw_descs__sz - fs_len - hs_len,
3168                                 __ffs_func_bind_do_descs, func);
3169                 if (unlikely(ss_len < 0)) {
3170                         ret = ss_len;
3171                         goto error;
3172                 }
3173         } else {
3174                 ss_len = 0;
3175         }
3176
3177         /*
3178          * Now handle interface numbers allocation and interface and
3179          * endpoint numbers rewriting.  We can do that in one go
3180          * now.
3181          */
3182         ret = ffs_do_descs(ffs->fs_descs_count +
3183                            (high ? ffs->hs_descs_count : 0) +
3184                            (super ? ffs->ss_descs_count : 0),
3185                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3186                            __ffs_func_bind_do_nums, func);
3187         if (unlikely(ret < 0))
3188                 goto error;
3189
3190         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3191         if (c->cdev->use_os_string) {
3192                 for (i = 0; i < ffs->interfaces_count; ++i) {
3193                         struct usb_os_desc *desc;
3194
3195                         desc = func->function.os_desc_table[i].os_desc =
3196                                 vla_ptr(vlabuf, d, os_desc) +
3197                                 i * sizeof(struct usb_os_desc);
3198                         desc->ext_compat_id =
3199                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3200                         INIT_LIST_HEAD(&desc->ext_prop);
3201                 }
3202                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3203                                       vla_ptr(vlabuf, d, raw_descs) +
3204                                       fs_len + hs_len + ss_len,
3205                                       d_raw_descs__sz - fs_len - hs_len -
3206                                       ss_len,
3207                                       __ffs_func_bind_do_os_desc, func);
3208                 if (unlikely(ret < 0))
3209                         goto error;
3210         }
3211         func->function.os_desc_n =
3212                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3213
3214         /* And we're done */
3215         ffs_event_add(ffs, FUNCTIONFS_BIND);
3216         return 0;
3217
3218 error:
3219         /* XXX Do we need to release all claimed endpoints here? */
3220         return ret;
3221 }
3222
3223 static int ffs_func_bind(struct usb_configuration *c,
3224                          struct usb_function *f)
3225 {
3226         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3227         struct ffs_function *func = ffs_func_from_usb(f);
3228         int ret;
3229
3230         if (IS_ERR(ffs_opts))
3231                 return PTR_ERR(ffs_opts);
3232
3233         ret = _ffs_func_bind(c, f);
3234         if (ret && !--ffs_opts->refcnt)
3235                 functionfs_unbind(func->ffs);
3236
3237         return ret;
3238 }
3239
3240
3241 /* Other USB function hooks *************************************************/
3242
3243 static void ffs_reset_work(struct work_struct *work)
3244 {
3245         struct ffs_data *ffs = container_of(work,
3246                 struct ffs_data, reset_work);
3247         ffs_data_reset(ffs);
3248 }
3249
3250 static int ffs_func_set_alt(struct usb_function *f,
3251                             unsigned interface, unsigned alt)
3252 {
3253         struct ffs_function *func = ffs_func_from_usb(f);
3254         struct ffs_data *ffs = func->ffs;
3255         int ret = 0, intf;
3256
3257         if (alt != (unsigned)-1) {
3258                 intf = ffs_func_revmap_intf(func, interface);
3259                 if (unlikely(intf < 0))
3260                         return intf;
3261         }
3262
3263         if (ffs->func)
3264                 ffs_func_eps_disable(ffs->func);
3265
3266         if (ffs->state == FFS_DEACTIVATED) {
3267                 ffs->state = FFS_CLOSING;
3268                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3269                 schedule_work(&ffs->reset_work);
3270                 return -ENODEV;
3271         }
3272
3273         if (ffs->state != FFS_ACTIVE)
3274                 return -ENODEV;
3275
3276         if (alt == (unsigned)-1) {
3277                 ffs->func = NULL;
3278                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3279                 return 0;
3280         }
3281
3282         ffs->func = func;
3283         ret = ffs_func_eps_enable(func);
3284         if (likely(ret >= 0))
3285                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3286         return ret;
3287 }
3288
3289 static void ffs_func_disable(struct usb_function *f)
3290 {
3291         ffs_func_set_alt(f, 0, (unsigned)-1);
3292 }
3293
3294 static int ffs_func_setup(struct usb_function *f,
3295                           const struct usb_ctrlrequest *creq)
3296 {
3297         struct ffs_function *func = ffs_func_from_usb(f);
3298         struct ffs_data *ffs = func->ffs;
3299         unsigned long flags;
3300         int ret;
3301
3302         ENTER();
3303
3304         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3305         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3306         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3307         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3308         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3309
3310         /*
3311          * Most requests directed to interface go through here
3312          * (notable exceptions are set/get interface) so we need to
3313          * handle them.  All other either handled by composite or
3314          * passed to usb_configuration->setup() (if one is set).  No
3315          * matter, we will handle requests directed to endpoint here
3316          * as well (as it's straightforward).  Other request recipient
3317          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3318          * is being used.
3319          */
3320         if (ffs->state != FFS_ACTIVE)
3321                 return -ENODEV;
3322
3323         switch (creq->bRequestType & USB_RECIP_MASK) {
3324         case USB_RECIP_INTERFACE:
3325                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3326                 if (unlikely(ret < 0))
3327                         return ret;
3328                 break;
3329
3330         case USB_RECIP_ENDPOINT:
3331                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3332                 if (unlikely(ret < 0))
3333                         return ret;
3334                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3335                         ret = func->ffs->eps_addrmap[ret];
3336                 break;
3337
3338         default:
3339                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3340                         ret = le16_to_cpu(creq->wIndex);
3341                 else
3342                         return -EOPNOTSUPP;
3343         }
3344
3345         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3346         ffs->ev.setup = *creq;
3347         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3348         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3349         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3350
3351         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3352 }
3353
3354 static bool ffs_func_req_match(struct usb_function *f,
3355                                const struct usb_ctrlrequest *creq,
3356                                bool config0)
3357 {
3358         struct ffs_function *func = ffs_func_from_usb(f);
3359
3360         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3361                 return false;
3362
3363         switch (creq->bRequestType & USB_RECIP_MASK) {
3364         case USB_RECIP_INTERFACE:
3365                 return (ffs_func_revmap_intf(func,
3366                                              le16_to_cpu(creq->wIndex)) >= 0);
3367         case USB_RECIP_ENDPOINT:
3368                 return (ffs_func_revmap_ep(func,
3369                                            le16_to_cpu(creq->wIndex)) >= 0);
3370         default:
3371                 return (bool) (func->ffs->user_flags &
3372                                FUNCTIONFS_ALL_CTRL_RECIP);
3373         }
3374 }
3375
3376 static void ffs_func_suspend(struct usb_function *f)
3377 {
3378         ENTER();
3379         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3380 }
3381
3382 static void ffs_func_resume(struct usb_function *f)
3383 {
3384         ENTER();
3385         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3386 }
3387
3388
3389 /* Endpoint and interface numbers reverse mapping ***************************/
3390
3391 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3392 {
3393         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3394         return num ? num : -EDOM;
3395 }
3396
3397 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3398 {
3399         short *nums = func->interfaces_nums;
3400         unsigned count = func->ffs->interfaces_count;
3401
3402         for (; count; --count, ++nums) {
3403                 if (*nums >= 0 && *nums == intf)
3404                         return nums - func->interfaces_nums;
3405         }
3406
3407         return -EDOM;
3408 }
3409
3410
3411 /* Devices management *******************************************************/
3412
3413 static LIST_HEAD(ffs_devices);
3414
3415 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3416 {
3417         struct ffs_dev *dev;
3418
3419         if (!name)
3420                 return NULL;
3421
3422         list_for_each_entry(dev, &ffs_devices, entry) {
3423                 if (strcmp(dev->name, name) == 0)
3424                         return dev;
3425         }
3426
3427         return NULL;
3428 }
3429
3430 /*
3431  * ffs_lock must be taken by the caller of this function
3432  */
3433 static struct ffs_dev *_ffs_get_single_dev(void)
3434 {
3435         struct ffs_dev *dev;
3436
3437         if (list_is_singular(&ffs_devices)) {
3438                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3439                 if (dev->single)
3440                         return dev;
3441         }
3442
3443         return NULL;
3444 }
3445
3446 /*
3447  * ffs_lock must be taken by the caller of this function
3448  */
3449 static struct ffs_dev *_ffs_find_dev(const char *name)
3450 {
3451         struct ffs_dev *dev;
3452
3453         dev = _ffs_get_single_dev();
3454         if (dev)
3455                 return dev;
3456
3457         return _ffs_do_find_dev(name);
3458 }
3459
3460 /* Configfs support *********************************************************/
3461
3462 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3463 {
3464         return container_of(to_config_group(item), struct f_fs_opts,
3465                             func_inst.group);
3466 }
3467
3468 static void ffs_attr_release(struct config_item *item)
3469 {
3470         struct f_fs_opts *opts = to_ffs_opts(item);
3471
3472         usb_put_function_instance(&opts->func_inst);
3473 }
3474
3475 static struct configfs_item_operations ffs_item_ops = {
3476         .release        = ffs_attr_release,
3477 };
3478
3479 static const struct config_item_type ffs_func_type = {
3480         .ct_item_ops    = &ffs_item_ops,
3481         .ct_owner       = THIS_MODULE,
3482 };
3483
3484
3485 /* Function registration interface ******************************************/
3486
3487 static void ffs_free_inst(struct usb_function_instance *f)
3488 {
3489         struct f_fs_opts *opts;
3490
3491         opts = to_f_fs_opts(f);
3492         ffs_dev_lock();
3493         _ffs_free_dev(opts->dev);
3494         ffs_dev_unlock();
3495         kfree(opts);
3496 }
3497
3498 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3499 {
3500         if (strlen(name) >= FIELD_SIZEOF(struct ffs_dev, name))
3501                 return -ENAMETOOLONG;
3502         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3503 }
3504
3505 static struct usb_function_instance *ffs_alloc_inst(void)
3506 {
3507         struct f_fs_opts *opts;
3508         struct ffs_dev *dev;
3509
3510         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3511         if (!opts)
3512                 return ERR_PTR(-ENOMEM);
3513
3514         opts->func_inst.set_inst_name = ffs_set_inst_name;
3515         opts->func_inst.free_func_inst = ffs_free_inst;
3516         ffs_dev_lock();
3517         dev = _ffs_alloc_dev();
3518         ffs_dev_unlock();
3519         if (IS_ERR(dev)) {
3520                 kfree(opts);
3521                 return ERR_CAST(dev);
3522         }
3523         opts->dev = dev;
3524         dev->opts = opts;
3525
3526         config_group_init_type_name(&opts->func_inst.group, "",
3527                                     &ffs_func_type);
3528         return &opts->func_inst;
3529 }
3530
3531 static void ffs_free(struct usb_function *f)
3532 {
3533         kfree(ffs_func_from_usb(f));
3534 }
3535
3536 static void ffs_func_unbind(struct usb_configuration *c,
3537                             struct usb_function *f)
3538 {
3539         struct ffs_function *func = ffs_func_from_usb(f);
3540         struct ffs_data *ffs = func->ffs;
3541         struct f_fs_opts *opts =
3542                 container_of(f->fi, struct f_fs_opts, func_inst);
3543         struct ffs_ep *ep = func->eps;
3544         unsigned count = ffs->eps_count;
3545         unsigned long flags;
3546
3547         ENTER();
3548         if (ffs->func == func) {
3549                 ffs_func_eps_disable(func);
3550                 ffs->func = NULL;
3551         }
3552
3553         if (!--opts->refcnt)
3554                 functionfs_unbind(ffs);
3555
3556         /* cleanup after autoconfig */
3557         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3558         while (count--) {
3559                 if (ep->ep && ep->req)
3560                         usb_ep_free_request(ep->ep, ep->req);
3561                 ep->req = NULL;
3562                 ++ep;
3563         }
3564         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3565         kfree(func->eps);
3566         func->eps = NULL;
3567         /*
3568          * eps, descriptors and interfaces_nums are allocated in the
3569          * same chunk so only one free is required.
3570          */
3571         func->function.fs_descriptors = NULL;
3572         func->function.hs_descriptors = NULL;
3573         func->function.ss_descriptors = NULL;
3574         func->interfaces_nums = NULL;
3575
3576         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3577 }
3578
3579 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3580 {
3581         struct ffs_function *func;
3582
3583         ENTER();
3584
3585         func = kzalloc(sizeof(*func), GFP_KERNEL);
3586         if (unlikely(!func))
3587                 return ERR_PTR(-ENOMEM);
3588
3589         func->function.name    = "Function FS Gadget";
3590
3591         func->function.bind    = ffs_func_bind;
3592         func->function.unbind  = ffs_func_unbind;
3593         func->function.set_alt = ffs_func_set_alt;
3594         func->function.disable = ffs_func_disable;
3595         func->function.setup   = ffs_func_setup;
3596         func->function.req_match = ffs_func_req_match;
3597         func->function.suspend = ffs_func_suspend;
3598         func->function.resume  = ffs_func_resume;
3599         func->function.free_func = ffs_free;
3600
3601         return &func->function;
3602 }
3603
3604 /*
3605  * ffs_lock must be taken by the caller of this function
3606  */
3607 static struct ffs_dev *_ffs_alloc_dev(void)
3608 {
3609         struct ffs_dev *dev;
3610         int ret;
3611
3612         if (_ffs_get_single_dev())
3613                         return ERR_PTR(-EBUSY);
3614
3615         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3616         if (!dev)
3617                 return ERR_PTR(-ENOMEM);
3618
3619         if (list_empty(&ffs_devices)) {
3620                 ret = functionfs_init();
3621                 if (ret) {
3622                         kfree(dev);
3623                         return ERR_PTR(ret);
3624                 }
3625         }
3626
3627         list_add(&dev->entry, &ffs_devices);
3628
3629         return dev;
3630 }
3631
3632 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3633 {
3634         struct ffs_dev *existing;
3635         int ret = 0;
3636
3637         ffs_dev_lock();
3638
3639         existing = _ffs_do_find_dev(name);
3640         if (!existing)
3641                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3642         else if (existing != dev)
3643                 ret = -EBUSY;
3644
3645         ffs_dev_unlock();
3646
3647         return ret;
3648 }
3649 EXPORT_SYMBOL_GPL(ffs_name_dev);
3650
3651 int ffs_single_dev(struct ffs_dev *dev)
3652 {
3653         int ret;
3654
3655         ret = 0;
3656         ffs_dev_lock();
3657
3658         if (!list_is_singular(&ffs_devices))
3659                 ret = -EBUSY;
3660         else
3661                 dev->single = true;
3662
3663         ffs_dev_unlock();
3664         return ret;
3665 }
3666 EXPORT_SYMBOL_GPL(ffs_single_dev);
3667
3668 /*
3669  * ffs_lock must be taken by the caller of this function
3670  */
3671 static void _ffs_free_dev(struct ffs_dev *dev)
3672 {
3673         list_del(&dev->entry);
3674
3675         /* Clear the private_data pointer to stop incorrect dev access */
3676         if (dev->ffs_data)
3677                 dev->ffs_data->private_data = NULL;
3678
3679         kfree(dev);
3680         if (list_empty(&ffs_devices))
3681                 functionfs_cleanup();
3682 }
3683
3684 static void *ffs_acquire_dev(const char *dev_name)
3685 {
3686         struct ffs_dev *ffs_dev;
3687
3688         ENTER();
3689         ffs_dev_lock();
3690
3691         ffs_dev = _ffs_find_dev(dev_name);
3692         if (!ffs_dev)
3693                 ffs_dev = ERR_PTR(-ENOENT);
3694         else if (ffs_dev->mounted)
3695                 ffs_dev = ERR_PTR(-EBUSY);
3696         else if (ffs_dev->ffs_acquire_dev_callback &&
3697             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3698                 ffs_dev = ERR_PTR(-ENOENT);
3699         else
3700                 ffs_dev->mounted = true;
3701
3702         ffs_dev_unlock();
3703         return ffs_dev;
3704 }
3705
3706 static void ffs_release_dev(struct ffs_data *ffs_data)
3707 {
3708         struct ffs_dev *ffs_dev;
3709
3710         ENTER();
3711         ffs_dev_lock();
3712
3713         ffs_dev = ffs_data->private_data;
3714         if (ffs_dev) {
3715                 ffs_dev->mounted = false;
3716
3717                 if (ffs_dev->ffs_release_dev_callback)
3718                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3719         }
3720
3721         ffs_dev_unlock();
3722 }
3723
3724 static int ffs_ready(struct ffs_data *ffs)
3725 {
3726         struct ffs_dev *ffs_obj;
3727         int ret = 0;
3728
3729         ENTER();
3730         ffs_dev_lock();
3731
3732         ffs_obj = ffs->private_data;
3733         if (!ffs_obj) {
3734                 ret = -EINVAL;
3735                 goto done;
3736         }
3737         if (WARN_ON(ffs_obj->desc_ready)) {
3738                 ret = -EBUSY;
3739                 goto done;
3740         }
3741
3742         ffs_obj->desc_ready = true;
3743         ffs_obj->ffs_data = ffs;
3744
3745         if (ffs_obj->ffs_ready_callback) {
3746                 ret = ffs_obj->ffs_ready_callback(ffs);
3747                 if (ret)
3748                         goto done;
3749         }
3750
3751         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3752 done:
3753         ffs_dev_unlock();
3754         return ret;
3755 }
3756
3757 static void ffs_closed(struct ffs_data *ffs)
3758 {
3759         struct ffs_dev *ffs_obj;
3760         struct f_fs_opts *opts;
3761         struct config_item *ci;
3762
3763         ENTER();
3764         ffs_dev_lock();
3765
3766         ffs_obj = ffs->private_data;
3767         if (!ffs_obj)
3768                 goto done;
3769
3770         ffs_obj->desc_ready = false;
3771         ffs_obj->ffs_data = NULL;
3772
3773         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3774             ffs_obj->ffs_closed_callback)
3775                 ffs_obj->ffs_closed_callback(ffs);
3776
3777         if (ffs_obj->opts)
3778                 opts = ffs_obj->opts;
3779         else
3780                 goto done;
3781
3782         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3783             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3784                 goto done;
3785
3786         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3787         ffs_dev_unlock();
3788
3789         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3790                 unregister_gadget_item(ci);
3791         return;
3792 done:
3793         ffs_dev_unlock();
3794 }
3795
3796 /* Misc helper functions ****************************************************/
3797
3798 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3799 {
3800         return nonblock
3801                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3802                 : mutex_lock_interruptible(mutex);
3803 }
3804
3805 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3806 {
3807         char *data;
3808
3809         if (unlikely(!len))
3810                 return NULL;
3811
3812         data = kmalloc(len, GFP_KERNEL);
3813         if (unlikely(!data))
3814                 return ERR_PTR(-ENOMEM);
3815
3816         if (unlikely(copy_from_user(data, buf, len))) {
3817                 kfree(data);
3818                 return ERR_PTR(-EFAULT);
3819         }
3820
3821         pr_vdebug("Buffer from user space:\n");
3822         ffs_dump_mem("", data, len);
3823
3824         return data;
3825 }
3826
3827 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3828 MODULE_LICENSE("GPL");
3829 MODULE_AUTHOR("Michal Nazarewicz");