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/fs_parser.h>
  21 #include <linux/hid.h>
  22 #include <linux/mm.h>
  23 #include <linux/module.h>
  24 #include <linux/scatterlist.h>
  25 #include <linux/sched/signal.h>
  26 #include <linux/uio.h>
  27 #include <linux/vmalloc.h>
  28 #include <asm/unaligned.h>
  29
  30 #include <linux/usb/ccid.h>
  31 #include <linux/usb/composite.h>
  32 #include <linux/usb/functionfs.h>
  33
  34 #include <linux/aio.h>
  35 #include <linux/mmu_context.h>
  36 #include <linux/poll.h>
  37 #include <linux/eventfd.h>
  38
  39 #include "u_fs.h"
  40 #include "u_f.h"
  41 #include "u_os_desc.h"
  42 #include "configfs.h"
  43
  44 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  45
  46 /* Reference counter handling */
  47 static void ffs_data_get(struct ffs_data *ffs);
  48 static void ffs_data_put(struct ffs_data *ffs);
  49 /* Creates new ffs_data object. */
  50 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  51         __attribute__((malloc));
  52
  53 /* Opened counter handling. */
  54 static void ffs_data_opened(struct ffs_data *ffs);
  55 static void ffs_data_closed(struct ffs_data *ffs);
  56
  57 /* Called with ffs->mutex held; take over ownership of data. */
  58 static int __must_check
  59 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  60 static int __must_check
  61 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  62
  63
  64 /* The function structure ***************************************************/
  65
  66 struct ffs_ep;
  67
  68 struct ffs_function {
  69         struct usb_configuration        *conf;
  70         struct usb_gadget               *gadget;
  71         struct ffs_data                 *ffs;
  72
  73         struct ffs_ep                   *eps;
  74         u8                              eps_revmap[16];
  75         short                           *interfaces_nums;
  76
  77         struct usb_function             function;
  78 };
  79
  80
  81 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  82 {
  83         return container_of(f, struct ffs_function, function);
  84 }
  85
  86
  87 static inline enum ffs_setup_state
  88 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  89 {
  90         return (enum ffs_setup_state)
  91                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  92 }
  93
  94
  95 static void ffs_func_eps_disable(struct ffs_function *func);
  96 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  97
  98 static int ffs_func_bind(struct usb_configuration *,
  99                          struct usb_function *);
 100 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 101 static void ffs_func_disable(struct usb_function *);
 102 static int ffs_func_setup(struct usb_function *,
 103                           const struct usb_ctrlrequest *);
 104 static bool ffs_func_req_match(struct usb_function *,
 105                                const struct usb_ctrlrequest *,
 106                                bool config0);
 107 static void ffs_func_suspend(struct usb_function *);
 108 static void ffs_func_resume(struct usb_function *);
 109
 110
 111 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 112 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 113
 114
 115 /* The endpoints structures *************************************************/
 116
 117 struct ffs_ep {
 118         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 119         struct usb_request              *req;   /* P: epfile->mutex */
 120
 121         /* [0]: full speed, [1]: high speed, [2]: super speed */
 122         struct usb_endpoint_descriptor  *descs[3];
 123
 124         u8                              num;
 125
 126         int                             status; /* P: epfile->mutex */
 127 };
 128
 129 struct ffs_epfile {
 130         /* Protects ep->ep and ep->req. */
 131         struct mutex                    mutex;
 132
 133         struct ffs_data                 *ffs;
 134         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 135
 136         struct dentry                   *dentry;
 137
 138         /*
 139          * Buffer for holding data from partial reads which may happen since
 140          * we’re rounding user read requests to a multiple of a max packet size.
 141          *
 142          * The pointer is initialised with NULL value and may be set by
 143          * __ffs_epfile_read_data function to point to a temporary buffer.
 144          *
 145          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 146          * data from said buffer and eventually free it.  Importantly, while the
 147          * function is using the buffer, it sets the pointer to NULL.  This is
 148          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 149          * can never run concurrently (they are synchronised by epfile->mutex)
 150          * so the latter will not assign a new value to the pointer.
 151          *
 152          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 153          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 154          * value is crux of the synchronisation between ffs_func_eps_disable and
 155          * __ffs_epfile_read_data.
 156          *
 157          * Once __ffs_epfile_read_data is about to finish it will try to set the
 158          * pointer back to its old value (as described above), but seeing as the
 159          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 160          * the buffer.
 161          *
 162          * == State transitions ==
 163          *
 164          * • ptr == NULL:  (initial state)
 165          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 166          *   ◦ __ffs_epfile_read_buffered:    nop
 167          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 168          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 169          * • ptr == DROP:
 170          *   ◦ __ffs_epfile_read_buffer_free: nop
 171          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 172          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 173          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 174          * • ptr == buf:
 175          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 176          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 177          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 178          *                                    is always called first
 179          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 180          * • ptr == NULL and reading:
 181          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 182          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 183          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 184          *   ◦ reading finishes and …
 185          *     … all data read:               free buf, go to ptr == NULL
 186          *     … otherwise:                   go to ptr == buf and reading
 187          * • ptr == DROP and reading:
 188          *   ◦ __ffs_epfile_read_buffer_free: nop
 189          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 190          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 191          *   ◦ reading finishes:              free buf, go to ptr == DROP
 192          */
 193         struct ffs_buffer               *read_buffer;
 194 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 195
 196         char                            name[5];
 197
 198         unsigned char                   in;     /* P: ffs->eps_lock */
 199         unsigned char                   isoc;   /* P: ffs->eps_lock */
 200
 201         unsigned char                   _pad;
 202 };
 203
 204 struct ffs_buffer {
 205         size_t length;
 206         char *data;
 207         char storage[];
 208 };
 209
 210 /*  ffs_io_data structure ***************************************************/
 211
 212 struct ffs_io_data {
 213         bool aio;
 214         bool read;
 215
 216         struct kiocb *kiocb;
 217         struct iov_iter data;
 218         const void *to_free;
 219         char *buf;
 220
 221         struct mm_struct *mm;
 222         struct work_struct work;
 223
 224         struct usb_ep *ep;
 225         struct usb_request *req;
 226         struct sg_table sgt;
 227         bool use_sg;
 228
 229         struct ffs_data *ffs;
 230 };
 231
 232 struct ffs_desc_helper {
 233         struct ffs_data *ffs;
 234         unsigned interfaces_count;
 235         unsigned eps_count;
 236 };
 237
 238 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 239 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 240
 241 static struct dentry *
 242 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 243                    const struct file_operations *fops);
 244
 245 /* Devices management *******************************************************/
 246
 247 DEFINE_MUTEX(ffs_lock);
 248 EXPORT_SYMBOL_GPL(ffs_lock);
 249
 250 static struct ffs_dev *_ffs_find_dev(const char *name);
 251 static struct ffs_dev *_ffs_alloc_dev(void);
 252 static void _ffs_free_dev(struct ffs_dev *dev);
 253 static void *ffs_acquire_dev(const char *dev_name);
 254 static void ffs_release_dev(struct ffs_data *ffs_data);
 255 static int ffs_ready(struct ffs_data *ffs);
 256 static void ffs_closed(struct ffs_data *ffs);
 257
 258 /* Misc helper functions ****************************************************/
 259
 260 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 261         __attribute__((warn_unused_result, nonnull));
 262 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 263         __attribute__((warn_unused_result, nonnull));
 264
 265
 266 /* Control file aka ep0 *****************************************************/
 267
 268 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 269 {
 270         struct ffs_data *ffs = req->context;
 271
 272         complete(&ffs->ep0req_completion);
 273 }
 274
 275 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 276         __releases(&ffs->ev.waitq.lock)
 277 {
 278         struct usb_request *req = ffs->ep0req;
 279         int ret;
 280
 281         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 282
 283         spin_unlock_irq(&ffs->ev.waitq.lock);
 284
 285         req->buf      = data;
 286         req->length   = len;
 287
 288         /*
 289          * UDC layer requires to provide a buffer even for ZLP, but should
 290          * not use it at all. Let's provide some poisoned pointer to catch
 291          * possible bug in the driver.
 292          */
 293         if (req->buf == NULL)
 294                 req->buf = (void *)0xDEADBABE;
 295
 296         reinit_completion(&ffs->ep0req_completion);
 297
 298         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 299         if (unlikely(ret < 0))
 300                 return ret;
 301
 302         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 303         if (unlikely(ret)) {
 304                 usb_ep_dequeue(ffs->gadget->ep0, req);
 305                 return -EINTR;
 306         }
 307
 308         ffs->setup_state = FFS_NO_SETUP;
 309         return req->status ? req->status : req->actual;
 310 }
 311
 312 static int __ffs_ep0_stall(struct ffs_data *ffs)
 313 {
 314         if (ffs->ev.can_stall) {
 315                 pr_vdebug("ep0 stall\n");
 316                 usb_ep_set_halt(ffs->gadget->ep0);
 317                 ffs->setup_state = FFS_NO_SETUP;
 318                 return -EL2HLT;
 319         } else {
 320                 pr_debug("bogus ep0 stall!\n");
 321                 return -ESRCH;
 322         }
 323 }
 324
 325 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 326                              size_t len, loff_t *ptr)
 327 {
 328         struct ffs_data *ffs = file->private_data;
 329         ssize_t ret;
 330         char *data;
 331
 332         ENTER();
 333
 334         /* Fast check if setup was canceled */
 335         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 336                 return -EIDRM;
 337
 338         /* Acquire mutex */
 339         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 340         if (unlikely(ret < 0))
 341                 return ret;
 342
 343         /* Check state */
 344         switch (ffs->state) {
 345         case FFS_READ_DESCRIPTORS:
 346         case FFS_READ_STRINGS:
 347                 /* Copy data */
 348                 if (unlikely(len < 16)) {
 349                         ret = -EINVAL;
 350                         break;
 351                 }
 352
 353                 data = ffs_prepare_buffer(buf, len);
 354                 if (IS_ERR(data)) {
 355                         ret = PTR_ERR(data);
 356                         break;
 357                 }
 358
 359                 /* Handle data */
 360                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 361                         pr_info("read descriptors\n");
 362                         ret = __ffs_data_got_descs(ffs, data, len);
 363                         if (unlikely(ret < 0))
 364                                 break;
 365
 366                         ffs->state = FFS_READ_STRINGS;
 367                         ret = len;
 368                 } else {
 369                         pr_info("read strings\n");
 370                         ret = __ffs_data_got_strings(ffs, data, len);
 371                         if (unlikely(ret < 0))
 372                                 break;
 373
 374                         ret = ffs_epfiles_create(ffs);
 375                         if (unlikely(ret)) {
 376                                 ffs->state = FFS_CLOSING;
 377                                 break;
 378                         }
 379
 380                         ffs->state = FFS_ACTIVE;
 381                         mutex_unlock(&ffs->mutex);
 382
 383                         ret = ffs_ready(ffs);
 384                         if (unlikely(ret < 0)) {
 385                                 ffs->state = FFS_CLOSING;
 386                                 return ret;
 387                         }
 388
 389                         return len;
 390                 }
 391                 break;
 392
 393         case FFS_ACTIVE:
 394                 data = NULL;
 395                 /*
 396                  * We're called from user space, we can use _irq
 397                  * rather then _irqsave
 398                  */
 399                 spin_lock_irq(&ffs->ev.waitq.lock);
 400                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 401                 case FFS_SETUP_CANCELLED:
 402                         ret = -EIDRM;
 403                         goto done_spin;
 404
 405                 case FFS_NO_SETUP:
 406                         ret = -ESRCH;
 407                         goto done_spin;
 408
 409                 case FFS_SETUP_PENDING:
 410                         break;
 411                 }
 412
 413                 /* FFS_SETUP_PENDING */
 414                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 415                         spin_unlock_irq(&ffs->ev.waitq.lock);
 416                         ret = __ffs_ep0_stall(ffs);
 417                         break;
 418                 }
 419
 420                 /* FFS_SETUP_PENDING and not stall */
 421                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 422
 423                 spin_unlock_irq(&ffs->ev.waitq.lock);
 424
 425                 data = ffs_prepare_buffer(buf, len);
 426                 if (IS_ERR(data)) {
 427                         ret = PTR_ERR(data);
 428                         break;
 429                 }
 430
 431                 spin_lock_irq(&ffs->ev.waitq.lock);
 432
 433                 /*
 434                  * We are guaranteed to be still in FFS_ACTIVE state
 435                  * but the state of setup could have changed from
 436                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 437                  * to check for that.  If that happened we copied data
 438                  * from user space in vain but it's unlikely.
 439                  *
 440                  * For sure we are not in FFS_NO_SETUP since this is
 441                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 442                  * transition can be performed and it's protected by
 443                  * mutex.
 444                  */
 445                 if (ffs_setup_state_clear_cancelled(ffs) ==
 446                     FFS_SETUP_CANCELLED) {
 447                         ret = -EIDRM;
 448 done_spin:
 449                         spin_unlock_irq(&ffs->ev.waitq.lock);
 450                 } else {
 451                         /* unlocks spinlock */
 452                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 453                 }
 454                 kfree(data);
 455                 break;
 456
 457         default:
 458                 ret = -EBADFD;
 459                 break;
 460         }
 461
 462         mutex_unlock(&ffs->mutex);
 463         return ret;
 464 }
 465
 466 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 467 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 468                                      size_t n)
 469         __releases(&ffs->ev.waitq.lock)
 470 {
 471         /*
 472          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 473          * size of ffs->ev.types array (which is four) so that's how much space
 474          * we reserve.
 475          */
 476         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 477         const size_t size = n * sizeof *events;
 478         unsigned i = 0;
 479
 480         memset(events, 0, size);
 481
 482         do {
 483                 events[i].type = ffs->ev.types[i];
 484                 if (events[i].type == FUNCTIONFS_SETUP) {
 485                         events[i].u.setup = ffs->ev.setup;
 486                         ffs->setup_state = FFS_SETUP_PENDING;
 487                 }
 488         } while (++i < n);
 489
 490         ffs->ev.count -= n;
 491         if (ffs->ev.count)
 492                 memmove(ffs->ev.types, ffs->ev.types + n,
 493                         ffs->ev.count * sizeof *ffs->ev.types);
 494
 495         spin_unlock_irq(&ffs->ev.waitq.lock);
 496         mutex_unlock(&ffs->mutex);
 497
 498         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 499 }
 500
 501 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 502                             size_t len, loff_t *ptr)
 503 {
 504         struct ffs_data *ffs = file->private_data;
 505         char *data = NULL;
 506         size_t n;
 507         int ret;
 508
 509         ENTER();
 510
 511         /* Fast check if setup was canceled */
 512         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 513                 return -EIDRM;
 514
 515         /* Acquire mutex */
 516         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 517         if (unlikely(ret < 0))
 518                 return ret;
 519
 520         /* Check state */
 521         if (ffs->state != FFS_ACTIVE) {
 522                 ret = -EBADFD;
 523                 goto done_mutex;
 524         }
 525
 526         /*
 527          * We're called from user space, we can use _irq rather then
 528          * _irqsave
 529          */
 530         spin_lock_irq(&ffs->ev.waitq.lock);
 531
 532         switch (ffs_setup_state_clear_cancelled(ffs)) {
 533         case FFS_SETUP_CANCELLED:
 534                 ret = -EIDRM;
 535                 break;
 536
 537         case FFS_NO_SETUP:
 538                 n = len / sizeof(struct usb_functionfs_event);
 539                 if (unlikely(!n)) {
 540                         ret = -EINVAL;
 541                         break;
 542                 }
 543
 544                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 545                         ret = -EAGAIN;
 546                         break;
 547                 }
 548
 549                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 550                                                         ffs->ev.count)) {
 551                         ret = -EINTR;
 552                         break;
 553                 }
 554
 555                 /* unlocks spinlock */
 556                 return __ffs_ep0_read_events(ffs, buf,
 557                                              min(n, (size_t)ffs->ev.count));
 558
 559         case FFS_SETUP_PENDING:
 560                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 561                         spin_unlock_irq(&ffs->ev.waitq.lock);
 562                         ret = __ffs_ep0_stall(ffs);
 563                         goto done_mutex;
 564                 }
 565
 566                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 567
 568                 spin_unlock_irq(&ffs->ev.waitq.lock);
 569
 570                 if (likely(len)) {
 571                         data = kmalloc(len, GFP_KERNEL);
 572                         if (unlikely(!data)) {
 573                                 ret = -ENOMEM;
 574                                 goto done_mutex;
 575                         }
 576                 }
 577
 578                 spin_lock_irq(&ffs->ev.waitq.lock);
 579
 580                 /* See ffs_ep0_write() */
 581                 if (ffs_setup_state_clear_cancelled(ffs) ==
 582                     FFS_SETUP_CANCELLED) {
 583                         ret = -EIDRM;
 584                         break;
 585                 }
 586
 587                 /* unlocks spinlock */
 588                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 589                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 590                         ret = -EFAULT;
 591                 goto done_mutex;
 592
 593         default:
 594                 ret = -EBADFD;
 595                 break;
 596         }
 597
 598         spin_unlock_irq(&ffs->ev.waitq.lock);
 599 done_mutex:
 600         mutex_unlock(&ffs->mutex);
 601         kfree(data);
 602         return ret;
 603 }
 604
 605 static int ffs_ep0_open(struct inode *inode, struct file *file)
 606 {
 607         struct ffs_data *ffs = inode->i_private;
 608
 609         ENTER();
 610
 611         if (unlikely(ffs->state == FFS_CLOSING))
 612                 return -EBUSY;
 613
 614         file->private_data = ffs;
 615         ffs_data_opened(ffs);
 616
 617         return 0;
 618 }
 619
 620 static int ffs_ep0_release(struct inode *inode, struct file *file)
 621 {
 622         struct ffs_data *ffs = file->private_data;
 623
 624         ENTER();
 625
 626         ffs_data_closed(ffs);
 627
 628         return 0;
 629 }
 630
 631 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 632 {
 633         struct ffs_data *ffs = file->private_data;
 634         struct usb_gadget *gadget = ffs->gadget;
 635         long ret;
 636
 637         ENTER();
 638
 639         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 640                 struct ffs_function *func = ffs->func;
 641                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 642         } else if (gadget && gadget->ops->ioctl) {
 643                 ret = gadget->ops->ioctl(gadget, code, value);
 644         } else {
 645                 ret = -ENOTTY;
 646         }
 647
 648         return ret;
 649 }
 650
 651 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 652 {
 653         struct ffs_data *ffs = file->private_data;
 654         __poll_t mask = EPOLLWRNORM;
 655         int ret;
 656
 657         poll_wait(file, &ffs->ev.waitq, wait);
 658
 659         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 660         if (unlikely(ret < 0))
 661                 return mask;
 662
 663         switch (ffs->state) {
 664         case FFS_READ_DESCRIPTORS:
 665         case FFS_READ_STRINGS:
 666                 mask |= EPOLLOUT;
 667                 break;
 668
 669         case FFS_ACTIVE:
 670                 switch (ffs->setup_state) {
 671                 case FFS_NO_SETUP:
 672                         if (ffs->ev.count)
 673                                 mask |= EPOLLIN;
 674                         break;
 675
 676                 case FFS_SETUP_PENDING:
 677                 case FFS_SETUP_CANCELLED:
 678                         mask |= (EPOLLIN | EPOLLOUT);
 679                         break;
 680                 }
 681         case FFS_CLOSING:
 682                 break;
 683         case FFS_DEACTIVATED:
 684                 break;
 685         }
 686
 687         mutex_unlock(&ffs->mutex);
 688
 689         return mask;
 690 }
 691
 692 static const struct file_operations ffs_ep0_operations = {
 693         .llseek =       no_llseek,
 694
 695         .open =         ffs_ep0_open,
 696         .write =        ffs_ep0_write,
 697         .read =         ffs_ep0_read,
 698         .release =      ffs_ep0_release,
 699         .unlocked_ioctl =       ffs_ep0_ioctl,
 700         .poll =         ffs_ep0_poll,
 701 };
 702
 703
 704 /* "Normal" endpoints operations ********************************************/
 705
 706 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 707 {
 708         ENTER();
 709         if (likely(req->context)) {
 710                 struct ffs_ep *ep = _ep->driver_data;
 711                 ep->status = req->status ? req->status : req->actual;
 712                 complete(req->context);
 713         }
 714 }
 715
 716 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 717 {
 718         ssize_t ret = copy_to_iter(data, data_len, iter);
 719         if (likely(ret == data_len))
 720                 return ret;
 721
 722         if (unlikely(iov_iter_count(iter)))
 723                 return -EFAULT;
 724
 725         /*
 726          * Dear user space developer!
 727          *
 728          * TL;DR: To stop getting below error message in your kernel log, change
 729          * user space code using functionfs to align read buffers to a max
 730          * packet size.
 731          *
 732          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 733          * packet size.  When unaligned buffer is passed to functionfs, it
 734          * internally uses a larger, aligned buffer so that such UDCs are happy.
 735          *
 736          * Unfortunately, this means that host may send more data than was
 737          * requested in read(2) system call.  f_fs doesn’t know what to do with
 738          * that excess data so it simply drops it.
 739          *
 740          * Was the buffer aligned in the first place, no such problem would
 741          * happen.
 742          *
 743          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 744          * by splitting a request into multiple parts.  This splitting may still
 745          * be a problem though so it’s likely best to align the buffer
 746          * regardless of it being AIO or not..
 747          *
 748          * This only affects OUT endpoints, i.e. reading data with a read(2),
 749          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 750          * affected.
 751          */
 752         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 753                "Align read buffer size to max packet size to avoid the problem.\n",
 754                data_len, ret);
 755
 756         return ret;
 757 }
 758
 759 /*
 760  * allocate a virtually contiguous buffer and create a scatterlist describing it
 761  * @sg_table    - pointer to a place to be filled with sg_table contents
 762  * @size        - required buffer size
 763  */
 764 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 765 {
 766         struct page **pages;
 767         void *vaddr, *ptr;
 768         unsigned int n_pages;
 769         int i;
 770
 771         vaddr = vmalloc(sz);
 772         if (!vaddr)
 773                 return NULL;
 774
 775         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 776         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 777         if (!pages) {
 778                 vfree(vaddr);
 779
 780                 return NULL;
 781         }
 782         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 783                 pages[i] = vmalloc_to_page(ptr);
 784
 785         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 786                 kvfree(pages);
 787                 vfree(vaddr);
 788
 789                 return NULL;
 790         }
 791         kvfree(pages);
 792
 793         return vaddr;
 794 }
 795
 796 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 797         size_t data_len)
 798 {
 799         if (io_data->use_sg)
 800                 return ffs_build_sg_list(&io_data->sgt, data_len);
 801
 802         return kmalloc(data_len, GFP_KERNEL);
 803 }
 804
 805 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 806 {
 807         if (!io_data->buf)
 808                 return;
 809
 810         if (io_data->use_sg) {
 811                 sg_free_table(&io_data->sgt);
 812                 vfree(io_data->buf);
 813         } else {
 814                 kfree(io_data->buf);
 815         }
 816 }
 817
 818 static void ffs_user_copy_worker(struct work_struct *work)
 819 {
 820         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 821                                                    work);
 822         int ret = io_data->req->status ? io_data->req->status :
 823                                          io_data->req->actual;
 824         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 825
 826         if (io_data->read && ret > 0) {
 827                 mm_segment_t oldfs = get_fs();
 828
 829                 set_fs(USER_DS);
 830                 use_mm(io_data->mm);
 831                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 832                 unuse_mm(io_data->mm);
 833                 set_fs(oldfs);
 834         }
 835
 836         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 837
 838         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 839                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 840
 841         usb_ep_free_request(io_data->ep, io_data->req);
 842
 843         if (io_data->read)
 844                 kfree(io_data->to_free);
 845         ffs_free_buffer(io_data);
 846         kfree(io_data);
 847 }
 848
 849 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 850                                          struct usb_request *req)
 851 {
 852         struct ffs_io_data *io_data = req->context;
 853         struct ffs_data *ffs = io_data->ffs;
 854
 855         ENTER();
 856
 857         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 858         queue_work(ffs->io_completion_wq, &io_data->work);
 859 }
 860
 861 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 862 {
 863         /*
 864          * See comment in struct ffs_epfile for full read_buffer pointer
 865          * synchronisation story.
 866          */
 867         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 868         if (buf && buf != READ_BUFFER_DROP)
 869                 kfree(buf);
 870 }
 871
 872 /* Assumes epfile->mutex is held. */
 873 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 874                                           struct iov_iter *iter)
 875 {
 876         /*
 877          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 878          * the buffer while we are using it.  See comment in struct ffs_epfile
 879          * for full read_buffer pointer synchronisation story.
 880          */
 881         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 882         ssize_t ret;
 883         if (!buf || buf == READ_BUFFER_DROP)
 884                 return 0;
 885
 886         ret = copy_to_iter(buf->data, buf->length, iter);
 887         if (buf->length == ret) {
 888                 kfree(buf);
 889                 return ret;
 890         }
 891
 892         if (unlikely(iov_iter_count(iter))) {
 893                 ret = -EFAULT;
 894         } else {
 895                 buf->length -= ret;
 896                 buf->data += ret;
 897         }
 898
 899         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 900                 kfree(buf);
 901
 902         return ret;
 903 }
 904
 905 /* Assumes epfile->mutex is held. */
 906 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 907                                       void *data, int data_len,
 908                                       struct iov_iter *iter)
 909 {
 910         struct ffs_buffer *buf;
 911
 912         ssize_t ret = copy_to_iter(data, data_len, iter);
 913         if (likely(data_len == ret))
 914                 return ret;
 915
 916         if (unlikely(iov_iter_count(iter)))
 917                 return -EFAULT;
 918
 919         /* See ffs_copy_to_iter for more context. */
 920         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 921                 data_len, ret);
 922
 923         data_len -= ret;
 924         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 925         if (!buf)
 926                 return -ENOMEM;
 927         buf->length = data_len;
 928         buf->data = buf->storage;
 929         memcpy(buf->storage, data + ret, data_len);
 930
 931         /*
 932          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 933          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 934          * in struct ffs_epfile for full read_buffer pointer synchronisation
 935          * story.
 936          */
 937         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 938                 kfree(buf);
 939
 940         return ret;
 941 }
 942
 943 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 944 {
 945         struct ffs_epfile *epfile = file->private_data;
 946         struct usb_request *req;
 947         struct ffs_ep *ep;
 948         char *data = NULL;
 949         ssize_t ret, data_len = -EINVAL;
 950         int halt;
 951
 952         /* Are we still active? */
 953         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 954                 return -ENODEV;
 955
 956         /* Wait for endpoint to be enabled */
 957         ep = epfile->ep;
 958         if (!ep) {
 959                 if (file->f_flags & O_NONBLOCK)
 960                         return -EAGAIN;
 961
 962                 ret = wait_event_interruptible(
 963                                 epfile->ffs->wait, (ep = epfile->ep));
 964                 if (ret)
 965                         return -EINTR;
 966         }
 967
 968         /* Do we halt? */
 969         halt = (!io_data->read == !epfile->in);
 970         if (halt && epfile->isoc)
 971                 return -EINVAL;
 972
 973         /* We will be using request and read_buffer */
 974         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 975         if (unlikely(ret))
 976                 goto error;
 977
 978         /* Allocate & copy */
 979         if (!halt) {
 980                 struct usb_gadget *gadget;
 981
 982                 /*
 983                  * Do we have buffered data from previous partial read?  Check
 984                  * that for synchronous case only because we do not have
 985                  * facility to ‘wake up’ a pending asynchronous read and push
 986                  * buffered data to it which we would need to make things behave
 987                  * consistently.
 988                  */
 989                 if (!io_data->aio && io_data->read) {
 990                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 991                         if (ret)
 992                                 goto error_mutex;
 993                 }
 994
 995                 /*
 996                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 997                  * before the waiting completes, so do not assign to 'gadget'
 998                  * earlier
 999                  */
1000                 gadget = epfile->ffs->gadget;
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
1016                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1017                 spin_unlock_irq(&epfile->ffs->eps_lock);
1018
1019                 data = ffs_alloc_buffer(io_data, data_len);
1020                 if (unlikely(!data)) {
1021                         ret = -ENOMEM;
1022                         goto error_mutex;
1023                 }
1024                 if (!io_data->read &&
1025                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1026                         ret = -EFAULT;
1027                         goto error_mutex;
1028                 }
1029         }
1030
1031         spin_lock_irq(&epfile->ffs->eps_lock);
1032
1033         if (epfile->ep != ep) {
1034                 /* In the meantime, endpoint got disabled or changed. */
1035                 ret = -ESHUTDOWN;
1036         } else if (halt) {
1037                 ret = usb_ep_set_halt(ep->ep);
1038                 if (!ret)
1039                         ret = -EBADMSG;
1040         } else if (unlikely(data_len == -EINVAL)) {
1041                 /*
1042                  * Sanity Check: even though data_len can't be used
1043                  * uninitialized at the time I write this comment, some
1044                  * compilers complain about this situation.
1045                  * In order to keep the code clean from warnings, data_len is
1046                  * being initialized to -EINVAL during its declaration, which
1047                  * means we can't rely on compiler anymore to warn no future
1048                  * changes won't result in data_len being used uninitialized.
1049                  * For such reason, we're adding this redundant sanity check
1050                  * here.
1051                  */
1052                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1053                 ret = -EINVAL;
1054         } else if (!io_data->aio) {
1055                 DECLARE_COMPLETION_ONSTACK(done);
1056                 bool interrupted = false;
1057
1058                 req = ep->req;
1059                 if (io_data->use_sg) {
1060                         req->buf = NULL;
1061                         req->sg = io_data->sgt.sgl;
1062                         req->num_sgs = io_data->sgt.nents;
1063                 } else {
1064                         req->buf = data;
1065                         req->num_sgs = 0;
1066                 }
1067                 req->length = data_len;
1068
1069                 io_data->buf = data;
1070
1071                 req->context  = &done;
1072                 req->complete = ffs_epfile_io_complete;
1073
1074                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1075                 if (unlikely(ret < 0))
1076                         goto error_lock;
1077
1078                 spin_unlock_irq(&epfile->ffs->eps_lock);
1079
1080                 if (unlikely(wait_for_completion_interruptible(&done))) {
1081                         /*
1082                          * To avoid race condition with ffs_epfile_io_complete,
1083                          * dequeue the request first then check
1084                          * status. usb_ep_dequeue API should guarantee no race
1085                          * condition with req->complete callback.
1086                          */
1087                         usb_ep_dequeue(ep->ep, req);
1088                         wait_for_completion(&done);
1089                         interrupted = ep->status < 0;
1090                 }
1091
1092                 if (interrupted)
1093                         ret = -EINTR;
1094                 else if (io_data->read && ep->status > 0)
1095                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1096                                                      &io_data->data);
1097                 else
1098                         ret = ep->status;
1099                 goto error_mutex;
1100         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1101                 ret = -ENOMEM;
1102         } else {
1103                 if (io_data->use_sg) {
1104                         req->buf = NULL;
1105                         req->sg = io_data->sgt.sgl;
1106                         req->num_sgs = io_data->sgt.nents;
1107                 } else {
1108                         req->buf = data;
1109                         req->num_sgs = 0;
1110                 }
1111                 req->length = data_len;
1112
1113                 io_data->buf = data;
1114                 io_data->ep = ep->ep;
1115                 io_data->req = req;
1116                 io_data->ffs = epfile->ffs;
1117
1118                 req->context  = io_data;
1119                 req->complete = ffs_epfile_async_io_complete;
1120
1121                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1122                 if (unlikely(ret)) {
1123                         usb_ep_free_request(ep->ep, req);
1124                         goto error_lock;
1125                 }
1126
1127                 ret = -EIOCBQUEUED;
1128                 /*
1129                  * Do not kfree the buffer in this function.  It will be freed
1130                  * by ffs_user_copy_worker.
1131                  */
1132                 data = NULL;
1133         }
1134
1135 error_lock:
1136         spin_unlock_irq(&epfile->ffs->eps_lock);
1137 error_mutex:
1138         mutex_unlock(&epfile->mutex);
1139 error:
1140         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1141                 ffs_free_buffer(io_data);
1142         return ret;
1143 }
1144
1145 static int
1146 ffs_epfile_open(struct inode *inode, struct file *file)
1147 {
1148         struct ffs_epfile *epfile = inode->i_private;
1149
1150         ENTER();
1151
1152         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1153                 return -ENODEV;
1154
1155         file->private_data = epfile;
1156         ffs_data_opened(epfile->ffs);
1157
1158         return 0;
1159 }
1160
1161 static int ffs_aio_cancel(struct kiocb *kiocb)
1162 {
1163         struct ffs_io_data *io_data = kiocb->private;
1164         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1165         int value;
1166
1167         ENTER();
1168
1169         spin_lock_irq(&epfile->ffs->eps_lock);
1170
1171         if (likely(io_data && io_data->ep && io_data->req))
1172                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1173         else
1174                 value = -EINVAL;
1175
1176         spin_unlock_irq(&epfile->ffs->eps_lock);
1177
1178         return value;
1179 }
1180
1181 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1182 {
1183         struct ffs_io_data io_data, *p = &io_data;
1184         ssize_t res;
1185
1186         ENTER();
1187
1188         if (!is_sync_kiocb(kiocb)) {
1189                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1190                 if (unlikely(!p))
1191                         return -ENOMEM;
1192                 p->aio = true;
1193         } else {
1194                 memset(p, 0, sizeof(*p));
1195                 p->aio = false;
1196         }
1197
1198         p->read = false;
1199         p->kiocb = kiocb;
1200         p->data = *from;
1201         p->mm = current->mm;
1202
1203         kiocb->private = p;
1204
1205         if (p->aio)
1206                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1207
1208         res = ffs_epfile_io(kiocb->ki_filp, p);
1209         if (res == -EIOCBQUEUED)
1210                 return res;
1211         if (p->aio)
1212                 kfree(p);
1213         else
1214                 *from = p->data;
1215         return res;
1216 }
1217
1218 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1219 {
1220         struct ffs_io_data io_data, *p = &io_data;
1221         ssize_t res;
1222
1223         ENTER();
1224
1225         if (!is_sync_kiocb(kiocb)) {
1226                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1227                 if (unlikely(!p))
1228                         return -ENOMEM;
1229                 p->aio = true;
1230         } else {
1231                 memset(p, 0, sizeof(*p));
1232                 p->aio = false;
1233         }
1234
1235         p->read = true;
1236         p->kiocb = kiocb;
1237         if (p->aio) {
1238                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1239                 if (!p->to_free) {
1240                         kfree(p);
1241                         return -ENOMEM;
1242                 }
1243         } else {
1244                 p->data = *to;
1245                 p->to_free = NULL;
1246         }
1247         p->mm = current->mm;
1248
1249         kiocb->private = p;
1250
1251         if (p->aio)
1252                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1253
1254         res = ffs_epfile_io(kiocb->ki_filp, p);
1255         if (res == -EIOCBQUEUED)
1256                 return res;
1257
1258         if (p->aio) {
1259                 kfree(p->to_free);
1260                 kfree(p);
1261         } else {
1262                 *to = p->data;
1263         }
1264         return res;
1265 }
1266
1267 static int
1268 ffs_epfile_release(struct inode *inode, struct file *file)
1269 {
1270         struct ffs_epfile *epfile = inode->i_private;
1271
1272         ENTER();
1273
1274         __ffs_epfile_read_buffer_free(epfile);
1275         ffs_data_closed(epfile->ffs);
1276
1277         return 0;
1278 }
1279
1280 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1281                              unsigned long value)
1282 {
1283         struct ffs_epfile *epfile = file->private_data;
1284         struct ffs_ep *ep;
1285         int ret;
1286
1287         ENTER();
1288
1289         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1290                 return -ENODEV;
1291
1292         /* Wait for endpoint to be enabled */
1293         ep = epfile->ep;
1294         if (!ep) {
1295                 if (file->f_flags & O_NONBLOCK)
1296                         return -EAGAIN;
1297
1298                 ret = wait_event_interruptible(
1299                                 epfile->ffs->wait, (ep = epfile->ep));
1300                 if (ret)
1301                         return -EINTR;
1302         }
1303
1304         spin_lock_irq(&epfile->ffs->eps_lock);
1305
1306         /* In the meantime, endpoint got disabled or changed. */
1307         if (epfile->ep != ep) {
1308                 spin_unlock_irq(&epfile->ffs->eps_lock);
1309                 return -ESHUTDOWN;
1310         }
1311
1312         switch (code) {
1313         case FUNCTIONFS_FIFO_STATUS:
1314                 ret = usb_ep_fifo_status(epfile->ep->ep);
1315                 break;
1316         case FUNCTIONFS_FIFO_FLUSH:
1317                 usb_ep_fifo_flush(epfile->ep->ep);
1318                 ret = 0;
1319                 break;
1320         case FUNCTIONFS_CLEAR_HALT:
1321                 ret = usb_ep_clear_halt(epfile->ep->ep);
1322                 break;
1323         case FUNCTIONFS_ENDPOINT_REVMAP:
1324                 ret = epfile->ep->num;
1325                 break;
1326         case FUNCTIONFS_ENDPOINT_DESC:
1327         {
1328                 int desc_idx;
1329                 struct usb_endpoint_descriptor *desc;
1330
1331                 switch (epfile->ffs->gadget->speed) {
1332                 case USB_SPEED_SUPER:
1333                         desc_idx = 2;
1334                         break;
1335                 case USB_SPEED_HIGH:
1336                         desc_idx = 1;
1337                         break;
1338                 default:
1339                         desc_idx = 0;
1340                 }
1341                 desc = epfile->ep->descs[desc_idx];
1342
1343                 spin_unlock_irq(&epfile->ffs->eps_lock);
1344                 ret = copy_to_user((void __user *)value, desc, desc->bLength);
1345                 if (ret)
1346                         ret = -EFAULT;
1347                 return ret;
1348         }
1349         default:
1350                 ret = -ENOTTY;
1351         }
1352         spin_unlock_irq(&epfile->ffs->eps_lock);
1353
1354         return ret;
1355 }
1356
1357 static const struct file_operations ffs_epfile_operations = {
1358         .llseek =       no_llseek,
1359
1360         .open =         ffs_epfile_open,
1361         .write_iter =   ffs_epfile_write_iter,
1362         .read_iter =    ffs_epfile_read_iter,
1363         .release =      ffs_epfile_release,
1364         .unlocked_ioctl =       ffs_epfile_ioctl,
1365         .compat_ioctl = compat_ptr_ioctl,
1366 };
1367
1368
1369 /* File system and super block operations ***********************************/
1370
1371 /*
1372  * Mounting the file system creates a controller file, used first for
1373  * function configuration then later for event monitoring.
1374  */
1375
1376 static struct inode *__must_check
1377 ffs_sb_make_inode(struct super_block *sb, void *data,
1378                   const struct file_operations *fops,
1379                   const struct inode_operations *iops,
1380                   struct ffs_file_perms *perms)
1381 {
1382         struct inode *inode;
1383
1384         ENTER();
1385
1386         inode = new_inode(sb);
1387
1388         if (likely(inode)) {
1389                 struct timespec64 ts = current_time(inode);
1390
1391                 inode->i_ino     = get_next_ino();
1392                 inode->i_mode    = perms->mode;
1393                 inode->i_uid     = perms->uid;
1394                 inode->i_gid     = perms->gid;
1395                 inode->i_atime   = ts;
1396                 inode->i_mtime   = ts;
1397                 inode->i_ctime   = ts;
1398                 inode->i_private = data;
1399                 if (fops)
1400                         inode->i_fop = fops;
1401                 if (iops)
1402                         inode->i_op  = iops;
1403         }
1404
1405         return inode;
1406 }
1407
1408 /* Create "regular" file */
1409 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1410                                         const char *name, void *data,
1411                                         const struct file_operations *fops)
1412 {
1413         struct ffs_data *ffs = sb->s_fs_info;
1414         struct dentry   *dentry;
1415         struct inode    *inode;
1416
1417         ENTER();
1418
1419         dentry = d_alloc_name(sb->s_root, name);
1420         if (unlikely(!dentry))
1421                 return NULL;
1422
1423         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1424         if (unlikely(!inode)) {
1425                 dput(dentry);
1426                 return NULL;
1427         }
1428
1429         d_add(dentry, inode);
1430         return dentry;
1431 }
1432
1433 /* Super block */
1434 static const struct super_operations ffs_sb_operations = {
1435         .statfs =       simple_statfs,
1436         .drop_inode =   generic_delete_inode,
1437 };
1438
1439 struct ffs_sb_fill_data {
1440         struct ffs_file_perms perms;
1441         umode_t root_mode;
1442         const char *dev_name;
1443         bool no_disconnect;
1444         struct ffs_data *ffs_data;
1445 };
1446
1447 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1448 {
1449         struct ffs_sb_fill_data *data = fc->fs_private;
1450         struct inode    *inode;
1451         struct ffs_data *ffs = data->ffs_data;
1452
1453         ENTER();
1454
1455         ffs->sb              = sb;
1456         data->ffs_data       = NULL;
1457         sb->s_fs_info        = ffs;
1458         sb->s_blocksize      = PAGE_SIZE;
1459         sb->s_blocksize_bits = PAGE_SHIFT;
1460         sb->s_magic          = FUNCTIONFS_MAGIC;
1461         sb->s_op             = &ffs_sb_operations;
1462         sb->s_time_gran      = 1;
1463
1464         /* Root inode */
1465         data->perms.mode = data->root_mode;
1466         inode = ffs_sb_make_inode(sb, NULL,
1467                                   &simple_dir_operations,
1468                                   &simple_dir_inode_operations,
1469                                   &data->perms);
1470         sb->s_root = d_make_root(inode);
1471         if (unlikely(!sb->s_root))
1472                 return -ENOMEM;
1473
1474         /* EP0 file */
1475         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1476                                          &ffs_ep0_operations)))
1477                 return -ENOMEM;
1478
1479         return 0;
1480 }
1481
1482 enum {
1483         Opt_no_disconnect,
1484         Opt_rmode,
1485         Opt_fmode,
1486         Opt_mode,
1487         Opt_uid,
1488         Opt_gid,
1489 };
1490
1491 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1492         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1493         fsparam_u32     ("rmode",               Opt_rmode),
1494         fsparam_u32     ("fmode",               Opt_fmode),
1495         fsparam_u32     ("mode",                Opt_mode),
1496         fsparam_u32     ("uid",                 Opt_uid),
1497         fsparam_u32     ("gid",                 Opt_gid),
1498         {}
1499 };
1500
1501 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1502 {
1503         struct ffs_sb_fill_data *data = fc->fs_private;
1504         struct fs_parse_result result;
1505         int opt;
1506
1507         ENTER();
1508
1509         opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1510         if (opt < 0)
1511                 return opt;
1512
1513         switch (opt) {
1514         case Opt_no_disconnect:
1515                 data->no_disconnect = result.boolean;
1516                 break;
1517         case Opt_rmode:
1518                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1519                 break;
1520         case Opt_fmode:
1521                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1522                 break;
1523         case Opt_mode:
1524                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1525                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1526                 break;
1527
1528         case Opt_uid:
1529                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1530                 if (!uid_valid(data->perms.uid))
1531                         goto unmapped_value;
1532                 break;
1533         case Opt_gid:
1534                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1535                 if (!gid_valid(data->perms.gid))
1536                         goto unmapped_value;
1537                 break;
1538
1539         default:
1540                 return -ENOPARAM;
1541         }
1542
1543         return 0;
1544
1545 unmapped_value:
1546         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1547 }
1548
1549 /*
1550  * Set up the superblock for a mount.
1551  */
1552 static int ffs_fs_get_tree(struct fs_context *fc)
1553 {
1554         struct ffs_sb_fill_data *ctx = fc->fs_private;
1555         void *ffs_dev;
1556         struct ffs_data *ffs;
1557
1558         ENTER();
1559
1560         if (!fc->source)
1561                 return invalf(fc, "No source specified");
1562
1563         ffs = ffs_data_new(fc->source);
1564         if (unlikely(!ffs))
1565                 return -ENOMEM;
1566         ffs->file_perms = ctx->perms;
1567         ffs->no_disconnect = ctx->no_disconnect;
1568
1569         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1570         if (unlikely(!ffs->dev_name)) {
1571                 ffs_data_put(ffs);
1572                 return -ENOMEM;
1573         }
1574
1575         ffs_dev = ffs_acquire_dev(ffs->dev_name);
1576         if (IS_ERR(ffs_dev)) {
1577                 ffs_data_put(ffs);
1578                 return PTR_ERR(ffs_dev);
1579         }
1580
1581         ffs->private_data = ffs_dev;
1582         ctx->ffs_data = ffs;
1583         return get_tree_nodev(fc, ffs_sb_fill);
1584 }
1585
1586 static void ffs_fs_free_fc(struct fs_context *fc)
1587 {
1588         struct ffs_sb_fill_data *ctx = fc->fs_private;
1589
1590         if (ctx) {
1591                 if (ctx->ffs_data) {
1592                         ffs_release_dev(ctx->ffs_data);
1593                         ffs_data_put(ctx->ffs_data);
1594                 }
1595
1596                 kfree(ctx);
1597         }
1598 }
1599
1600 static const struct fs_context_operations ffs_fs_context_ops = {
1601         .free           = ffs_fs_free_fc,
1602         .parse_param    = ffs_fs_parse_param,
1603         .get_tree       = ffs_fs_get_tree,
1604 };
1605
1606 static int ffs_fs_init_fs_context(struct fs_context *fc)
1607 {
1608         struct ffs_sb_fill_data *ctx;
1609
1610         ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1611         if (!ctx)
1612                 return -ENOMEM;
1613
1614         ctx->perms.mode = S_IFREG | 0600;
1615         ctx->perms.uid = GLOBAL_ROOT_UID;
1616         ctx->perms.gid = GLOBAL_ROOT_GID;
1617         ctx->root_mode = S_IFDIR | 0500;
1618         ctx->no_disconnect = false;
1619
1620         fc->fs_private = ctx;
1621         fc->ops = &ffs_fs_context_ops;
1622         return 0;
1623 }
1624
1625 static void
1626 ffs_fs_kill_sb(struct super_block *sb)
1627 {
1628         ENTER();
1629
1630         kill_litter_super(sb);
1631         if (sb->s_fs_info) {
1632                 ffs_release_dev(sb->s_fs_info);
1633                 ffs_data_closed(sb->s_fs_info);
1634         }
1635 }
1636
1637 static struct file_system_type ffs_fs_type = {
1638         .owner          = THIS_MODULE,
1639         .name           = "functionfs",
1640         .init_fs_context = ffs_fs_init_fs_context,
1641         .parameters     = ffs_fs_fs_parameters,
1642         .kill_sb        = ffs_fs_kill_sb,
1643 };
1644 MODULE_ALIAS_FS("functionfs");
1645
1646
1647 /* Driver's main init/cleanup functions *************************************/
1648
1649 static int functionfs_init(void)
1650 {
1651         int ret;
1652
1653         ENTER();
1654
1655         ret = register_filesystem(&ffs_fs_type);
1656         if (likely(!ret))
1657                 pr_info("file system registered\n");
1658         else
1659                 pr_err("failed registering file system (%d)\n", ret);
1660
1661         return ret;
1662 }
1663
1664 static void functionfs_cleanup(void)
1665 {
1666         ENTER();
1667
1668         pr_info("unloading\n");
1669         unregister_filesystem(&ffs_fs_type);
1670 }
1671
1672
1673 /* ffs_data and ffs_function construction and destruction code **************/
1674
1675 static void ffs_data_clear(struct ffs_data *ffs);
1676 static void ffs_data_reset(struct ffs_data *ffs);
1677
1678 static void ffs_data_get(struct ffs_data *ffs)
1679 {
1680         ENTER();
1681
1682         refcount_inc(&ffs->ref);
1683 }
1684
1685 static void ffs_data_opened(struct ffs_data *ffs)
1686 {
1687         ENTER();
1688
1689         refcount_inc(&ffs->ref);
1690         if (atomic_add_return(1, &ffs->opened) == 1 &&
1691                         ffs->state == FFS_DEACTIVATED) {
1692                 ffs->state = FFS_CLOSING;
1693                 ffs_data_reset(ffs);
1694         }
1695 }
1696
1697 static void ffs_data_put(struct ffs_data *ffs)
1698 {
1699         ENTER();
1700
1701         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1702                 pr_info("%s(): freeing\n", __func__);
1703                 ffs_data_clear(ffs);
1704                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1705                        waitqueue_active(&ffs->ep0req_completion.wait) ||
1706                        waitqueue_active(&ffs->wait));
1707                 destroy_workqueue(ffs->io_completion_wq);
1708                 kfree(ffs->dev_name);
1709                 kfree(ffs);
1710         }
1711 }
1712
1713 static void ffs_data_closed(struct ffs_data *ffs)
1714 {
1715         ENTER();
1716
1717         if (atomic_dec_and_test(&ffs->opened)) {
1718                 if (ffs->no_disconnect) {
1719                         ffs->state = FFS_DEACTIVATED;
1720                         if (ffs->epfiles) {
1721                                 ffs_epfiles_destroy(ffs->epfiles,
1722                                                    ffs->eps_count);
1723                                 ffs->epfiles = NULL;
1724                         }
1725                         if (ffs->setup_state == FFS_SETUP_PENDING)
1726                                 __ffs_ep0_stall(ffs);
1727                 } else {
1728                         ffs->state = FFS_CLOSING;
1729                         ffs_data_reset(ffs);
1730                 }
1731         }
1732         if (atomic_read(&ffs->opened) < 0) {
1733                 ffs->state = FFS_CLOSING;
1734                 ffs_data_reset(ffs);
1735         }
1736
1737         ffs_data_put(ffs);
1738 }
1739
1740 static struct ffs_data *ffs_data_new(const char *dev_name)
1741 {
1742         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1743         if (unlikely(!ffs))
1744                 return NULL;
1745
1746         ENTER();
1747
1748         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1749         if (!ffs->io_completion_wq) {
1750                 kfree(ffs);
1751                 return NULL;
1752         }
1753
1754         refcount_set(&ffs->ref, 1);
1755         atomic_set(&ffs->opened, 0);
1756         ffs->state = FFS_READ_DESCRIPTORS;
1757         mutex_init(&ffs->mutex);
1758         spin_lock_init(&ffs->eps_lock);
1759         init_waitqueue_head(&ffs->ev.waitq);
1760         init_waitqueue_head(&ffs->wait);
1761         init_completion(&ffs->ep0req_completion);
1762
1763         /* XXX REVISIT need to update it in some places, or do we? */
1764         ffs->ev.can_stall = 1;
1765
1766         return ffs;
1767 }
1768
1769 static void ffs_data_clear(struct ffs_data *ffs)
1770 {
1771         ENTER();
1772
1773         ffs_closed(ffs);
1774
1775         BUG_ON(ffs->gadget);
1776
1777         if (ffs->epfiles)
1778                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1779
1780         if (ffs->ffs_eventfd)
1781                 eventfd_ctx_put(ffs->ffs_eventfd);
1782
1783         kfree(ffs->raw_descs_data);
1784         kfree(ffs->raw_strings);
1785         kfree(ffs->stringtabs);
1786 }
1787
1788 static void ffs_data_reset(struct ffs_data *ffs)
1789 {
1790         ENTER();
1791
1792         ffs_data_clear(ffs);
1793
1794         ffs->epfiles = NULL;
1795         ffs->raw_descs_data = NULL;
1796         ffs->raw_descs = NULL;
1797         ffs->raw_strings = NULL;
1798         ffs->stringtabs = NULL;
1799
1800         ffs->raw_descs_length = 0;
1801         ffs->fs_descs_count = 0;
1802         ffs->hs_descs_count = 0;
1803         ffs->ss_descs_count = 0;
1804
1805         ffs->strings_count = 0;
1806         ffs->interfaces_count = 0;
1807         ffs->eps_count = 0;
1808
1809         ffs->ev.count = 0;
1810
1811         ffs->state = FFS_READ_DESCRIPTORS;
1812         ffs->setup_state = FFS_NO_SETUP;
1813         ffs->flags = 0;
1814 }
1815
1816
1817 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1818 {
1819         struct usb_gadget_strings **lang;
1820         int first_id;
1821
1822         ENTER();
1823
1824         if (WARN_ON(ffs->state != FFS_ACTIVE
1825                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1826                 return -EBADFD;
1827
1828         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1829         if (unlikely(first_id < 0))
1830                 return first_id;
1831
1832         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1833         if (unlikely(!ffs->ep0req))
1834                 return -ENOMEM;
1835         ffs->ep0req->complete = ffs_ep0_complete;
1836         ffs->ep0req->context = ffs;
1837
1838         lang = ffs->stringtabs;
1839         if (lang) {
1840                 for (; *lang; ++lang) {
1841                         struct usb_string *str = (*lang)->strings;
1842                         int id = first_id;
1843                         for (; str->s; ++id, ++str)
1844                                 str->id = id;
1845                 }
1846         }
1847
1848         ffs->gadget = cdev->gadget;
1849         ffs_data_get(ffs);
1850         return 0;
1851 }
1852
1853 static void functionfs_unbind(struct ffs_data *ffs)
1854 {
1855         ENTER();
1856
1857         if (!WARN_ON(!ffs->gadget)) {
1858                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1859                 ffs->ep0req = NULL;
1860                 ffs->gadget = NULL;
1861                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1862                 ffs_data_put(ffs);
1863         }
1864 }
1865
1866 static int ffs_epfiles_create(struct ffs_data *ffs)
1867 {
1868         struct ffs_epfile *epfile, *epfiles;
1869         unsigned i, count;
1870
1871         ENTER();
1872
1873         count = ffs->eps_count;
1874         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1875         if (!epfiles)
1876                 return -ENOMEM;
1877
1878         epfile = epfiles;
1879         for (i = 1; i <= count; ++i, ++epfile) {
1880                 epfile->ffs = ffs;
1881                 mutex_init(&epfile->mutex);
1882                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1883                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1884                 else
1885                         sprintf(epfile->name, "ep%u", i);
1886                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1887                                                  epfile,
1888                                                  &ffs_epfile_operations);
1889                 if (unlikely(!epfile->dentry)) {
1890                         ffs_epfiles_destroy(epfiles, i - 1);
1891                         return -ENOMEM;
1892                 }
1893         }
1894
1895         ffs->epfiles = epfiles;
1896         return 0;
1897 }
1898
1899 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1900 {
1901         struct ffs_epfile *epfile = epfiles;
1902
1903         ENTER();
1904
1905         for (; count; --count, ++epfile) {
1906                 BUG_ON(mutex_is_locked(&epfile->mutex));
1907                 if (epfile->dentry) {
1908                         d_delete(epfile->dentry);
1909                         dput(epfile->dentry);
1910                         epfile->dentry = NULL;
1911                 }
1912         }
1913
1914         kfree(epfiles);
1915 }
1916
1917 static void ffs_func_eps_disable(struct ffs_function *func)
1918 {
1919         struct ffs_ep *ep         = func->eps;
1920         struct ffs_epfile *epfile = func->ffs->epfiles;
1921         unsigned count            = func->ffs->eps_count;
1922         unsigned long flags;
1923
1924         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1925         while (count--) {
1926                 /* pending requests get nuked */
1927                 if (likely(ep->ep))
1928                         usb_ep_disable(ep->ep);
1929                 ++ep;
1930
1931                 if (epfile) {
1932                         epfile->ep = NULL;
1933                         __ffs_epfile_read_buffer_free(epfile);
1934                         ++epfile;
1935                 }
1936         }
1937         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1938 }
1939
1940 static int ffs_func_eps_enable(struct ffs_function *func)
1941 {
1942         struct ffs_data *ffs      = func->ffs;
1943         struct ffs_ep *ep         = func->eps;
1944         struct ffs_epfile *epfile = ffs->epfiles;
1945         unsigned count            = ffs->eps_count;
1946         unsigned long flags;
1947         int ret = 0;
1948
1949         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1950         while(count--) {
1951                 ep->ep->driver_data = ep;
1952
1953                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1954                 if (ret) {
1955                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1956                                         __func__, ep->ep->name, ret);
1957                         break;
1958                 }
1959
1960                 ret = usb_ep_enable(ep->ep);
1961                 if (likely(!ret)) {
1962                         epfile->ep = ep;
1963                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1964                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1965                 } else {
1966                         break;
1967                 }
1968
1969                 ++ep;
1970                 ++epfile;
1971         }
1972
1973         wake_up_interruptible(&ffs->wait);
1974         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1975
1976         return ret;
1977 }
1978
1979
1980 /* Parsing and building descriptors and strings *****************************/
1981
1982 /*
1983  * This validates if data pointed by data is a valid USB descriptor as
1984  * well as record how many interfaces, endpoints and strings are
1985  * required by given configuration.  Returns address after the
1986  * descriptor or NULL if data is invalid.
1987  */
1988
1989 enum ffs_entity_type {
1990         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1991 };
1992
1993 enum ffs_os_desc_type {
1994         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1995 };
1996
1997 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1998                                    u8 *valuep,
1999                                    struct usb_descriptor_header *desc,
2000                                    void *priv);
2001
2002 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2003                                     struct usb_os_desc_header *h, void *data,
2004                                     unsigned len, void *priv);
2005
2006 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2007                                            ffs_entity_callback entity,
2008                                            void *priv, int *current_class)
2009 {
2010         struct usb_descriptor_header *_ds = (void *)data;
2011         u8 length;
2012         int ret;
2013
2014         ENTER();
2015
2016         /* At least two bytes are required: length and type */
2017         if (len < 2) {
2018                 pr_vdebug("descriptor too short\n");
2019                 return -EINVAL;
2020         }
2021
2022         /* If we have at least as many bytes as the descriptor takes? */
2023         length = _ds->bLength;
2024         if (len < length) {
2025                 pr_vdebug("descriptor longer then available data\n");
2026                 return -EINVAL;
2027         }
2028
2029 #define __entity_check_INTERFACE(val)  1
2030 #define __entity_check_STRING(val)     (val)
2031 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2032 #define __entity(type, val) do {                                        \
2033                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2034                 if (unlikely(!__entity_check_ ##type(val))) {           \
2035                         pr_vdebug("invalid entity's value\n");          \
2036                         return -EINVAL;                                 \
2037                 }                                                       \
2038                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2039                 if (unlikely(ret < 0)) {                                \
2040                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2041                                  (val), ret);                           \
2042                         return ret;                                     \
2043                 }                                                       \
2044         } while (0)
2045
2046         /* Parse descriptor depending on type. */
2047         switch (_ds->bDescriptorType) {
2048         case USB_DT_DEVICE:
2049         case USB_DT_CONFIG:
2050         case USB_DT_STRING:
2051         case USB_DT_DEVICE_QUALIFIER:
2052                 /* function can't have any of those */
2053                 pr_vdebug("descriptor reserved for gadget: %d\n",
2054                       _ds->bDescriptorType);
2055                 return -EINVAL;
2056
2057         case USB_DT_INTERFACE: {
2058                 struct usb_interface_descriptor *ds = (void *)_ds;
2059                 pr_vdebug("interface descriptor\n");
2060                 if (length != sizeof *ds)
2061                         goto inv_length;
2062
2063                 __entity(INTERFACE, ds->bInterfaceNumber);
2064                 if (ds->iInterface)
2065                         __entity(STRING, ds->iInterface);
2066                 *current_class = ds->bInterfaceClass;
2067         }
2068                 break;
2069
2070         case USB_DT_ENDPOINT: {
2071                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2072                 pr_vdebug("endpoint descriptor\n");
2073                 if (length != USB_DT_ENDPOINT_SIZE &&
2074                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2075                         goto inv_length;
2076                 __entity(ENDPOINT, ds->bEndpointAddress);
2077         }
2078                 break;
2079
2080         case USB_TYPE_CLASS | 0x01:
2081                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2082                         pr_vdebug("hid descriptor\n");
2083                         if (length != sizeof(struct hid_descriptor))
2084                                 goto inv_length;
2085                         break;
2086                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2087                         pr_vdebug("ccid descriptor\n");
2088                         if (length != sizeof(struct ccid_descriptor))
2089                                 goto inv_length;
2090                         break;
2091                 } else {
2092                         pr_vdebug("unknown descriptor: %d for class %d\n",
2093                               _ds->bDescriptorType, *current_class);
2094                         return -EINVAL;
2095                 }
2096
2097         case USB_DT_OTG:
2098                 if (length != sizeof(struct usb_otg_descriptor))
2099                         goto inv_length;
2100                 break;
2101
2102         case USB_DT_INTERFACE_ASSOCIATION: {
2103                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2104                 pr_vdebug("interface association descriptor\n");
2105                 if (length != sizeof *ds)
2106                         goto inv_length;
2107                 if (ds->iFunction)
2108                         __entity(STRING, ds->iFunction);
2109         }
2110                 break;
2111
2112         case USB_DT_SS_ENDPOINT_COMP:
2113                 pr_vdebug("EP SS companion descriptor\n");
2114                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2115                         goto inv_length;
2116                 break;
2117
2118         case USB_DT_OTHER_SPEED_CONFIG:
2119         case USB_DT_INTERFACE_POWER:
2120         case USB_DT_DEBUG:
2121         case USB_DT_SECURITY:
2122         case USB_DT_CS_RADIO_CONTROL:
2123                 /* TODO */
2124                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2125                 return -EINVAL;
2126
2127         default:
2128                 /* We should never be here */
2129                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2130                 return -EINVAL;
2131
2132 inv_length:
2133                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2134                           _ds->bLength, _ds->bDescriptorType);
2135                 return -EINVAL;
2136         }
2137
2138 #undef __entity
2139 #undef __entity_check_DESCRIPTOR
2140 #undef __entity_check_INTERFACE
2141 #undef __entity_check_STRING
2142 #undef __entity_check_ENDPOINT
2143
2144         return length;
2145 }
2146
2147 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2148                                      ffs_entity_callback entity, void *priv)
2149 {
2150         const unsigned _len = len;
2151         unsigned long num = 0;
2152         int current_class = -1;
2153
2154         ENTER();
2155
2156         for (;;) {
2157                 int ret;
2158
2159                 if (num == count)
2160                         data = NULL;
2161
2162                 /* Record "descriptor" entity */
2163                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2164                 if (unlikely(ret < 0)) {
2165                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2166                                  num, ret);
2167                         return ret;
2168                 }
2169
2170                 if (!data)
2171                         return _len - len;
2172
2173                 ret = ffs_do_single_desc(data, len, entity, priv,
2174                         &current_class);
2175                 if (unlikely(ret < 0)) {
2176                         pr_debug("%s returns %d\n", __func__, ret);
2177                         return ret;
2178                 }
2179
2180                 len -= ret;
2181                 data += ret;
2182                 ++num;
2183         }
2184 }
2185
2186 static int __ffs_data_do_entity(enum ffs_entity_type type,
2187                                 u8 *valuep, struct usb_descriptor_header *desc,
2188                                 void *priv)
2189 {
2190         struct ffs_desc_helper *helper = priv;
2191         struct usb_endpoint_descriptor *d;
2192
2193         ENTER();
2194
2195         switch (type) {
2196         case FFS_DESCRIPTOR:
2197                 break;
2198
2199         case FFS_INTERFACE:
2200                 /*
2201                  * Interfaces are indexed from zero so if we
2202                  * encountered interface "n" then there are at least
2203                  * "n+1" interfaces.
2204                  */
2205                 if (*valuep >= helper->interfaces_count)
2206                         helper->interfaces_count = *valuep + 1;
2207                 break;
2208
2209         case FFS_STRING:
2210                 /*
2211                  * Strings are indexed from 1 (0 is reserved
2212                  * for languages list)
2213                  */
2214                 if (*valuep > helper->ffs->strings_count)
2215                         helper->ffs->strings_count = *valuep;
2216                 break;
2217
2218         case FFS_ENDPOINT:
2219                 d = (void *)desc;
2220                 helper->eps_count++;
2221                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2222                         return -EINVAL;
2223                 /* Check if descriptors for any speed were already parsed */
2224                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2225                         helper->ffs->eps_addrmap[helper->eps_count] =
2226                                 d->bEndpointAddress;
2227                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2228                                 d->bEndpointAddress)
2229                         return -EINVAL;
2230                 break;
2231         }
2232
2233         return 0;
2234 }
2235
2236 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2237                                    struct usb_os_desc_header *desc)
2238 {
2239         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2240         u16 w_index = le16_to_cpu(desc->wIndex);
2241
2242         if (bcd_version != 1) {
2243                 pr_vdebug("unsupported os descriptors version: %d",
2244                           bcd_version);
2245                 return -EINVAL;
2246         }
2247         switch (w_index) {
2248         case 0x4:
2249                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2250                 break;
2251         case 0x5:
2252                 *next_type = FFS_OS_DESC_EXT_PROP;
2253                 break;
2254         default:
2255                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2256                 return -EINVAL;
2257         }
2258
2259         return sizeof(*desc);
2260 }
2261
2262 /*
2263  * Process all extended compatibility/extended property descriptors
2264  * of a feature descriptor
2265  */
2266 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2267                                               enum ffs_os_desc_type type,
2268                                               u16 feature_count,
2269                                               ffs_os_desc_callback entity,
2270                                               void *priv,
2271                                               struct usb_os_desc_header *h)
2272 {
2273         int ret;
2274         const unsigned _len = len;
2275
2276         ENTER();
2277
2278         /* loop over all ext compat/ext prop descriptors */
2279         while (feature_count--) {
2280                 ret = entity(type, h, data, len, priv);
2281                 if (unlikely(ret < 0)) {
2282                         pr_debug("bad OS descriptor, type: %d\n", type);
2283                         return ret;
2284                 }
2285                 data += ret;
2286                 len -= ret;
2287         }
2288         return _len - len;
2289 }
2290
2291 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2292 static int __must_check ffs_do_os_descs(unsigned count,
2293                                         char *data, unsigned len,
2294                                         ffs_os_desc_callback entity, void *priv)
2295 {
2296         const unsigned _len = len;
2297         unsigned long num = 0;
2298
2299         ENTER();
2300
2301         for (num = 0; num < count; ++num) {
2302                 int ret;
2303                 enum ffs_os_desc_type type;
2304                 u16 feature_count;
2305                 struct usb_os_desc_header *desc = (void *)data;
2306
2307                 if (len < sizeof(*desc))
2308                         return -EINVAL;
2309
2310                 /*
2311                  * Record "descriptor" entity.
2312                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2313                  * Move the data pointer to the beginning of extended
2314                  * compatibilities proper or extended properties proper
2315                  * portions of the data
2316                  */
2317                 if (le32_to_cpu(desc->dwLength) > len)
2318                         return -EINVAL;
2319
2320                 ret = __ffs_do_os_desc_header(&type, desc);
2321                 if (unlikely(ret < 0)) {
2322                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2323                                  num, ret);
2324                         return ret;
2325                 }
2326                 /*
2327                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2328                  */
2329                 feature_count = le16_to_cpu(desc->wCount);
2330                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2331                     (feature_count > 255 || desc->Reserved))
2332                                 return -EINVAL;
2333                 len -= ret;
2334                 data += ret;
2335
2336                 /*
2337                  * Process all function/property descriptors
2338                  * of this Feature Descriptor
2339                  */
2340                 ret = ffs_do_single_os_desc(data, len, type,
2341                                             feature_count, entity, priv, desc);
2342                 if (unlikely(ret < 0)) {
2343                         pr_debug("%s returns %d\n", __func__, ret);
2344                         return ret;
2345                 }
2346
2347                 len -= ret;
2348                 data += ret;
2349         }
2350         return _len - len;
2351 }
2352
2353 /**
2354  * Validate contents of the buffer from userspace related to OS descriptors.
2355  */
2356 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2357                                  struct usb_os_desc_header *h, void *data,
2358                                  unsigned len, void *priv)
2359 {
2360         struct ffs_data *ffs = priv;
2361         u8 length;
2362
2363         ENTER();
2364
2365         switch (type) {
2366         case FFS_OS_DESC_EXT_COMPAT: {
2367                 struct usb_ext_compat_desc *d = data;
2368                 int i;
2369
2370                 if (len < sizeof(*d) ||
2371                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2372                         return -EINVAL;
2373                 if (d->Reserved1 != 1) {
2374                         /*
2375                          * According to the spec, Reserved1 must be set to 1
2376                          * but older kernels incorrectly rejected non-zero
2377                          * values.  We fix it here to avoid returning EINVAL
2378                          * in response to values we used to accept.
2379                          */
2380                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2381                         d->Reserved1 = 1;
2382                 }
2383                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2384                         if (d->Reserved2[i])
2385                                 return -EINVAL;
2386
2387                 length = sizeof(struct usb_ext_compat_desc);
2388         }
2389                 break;
2390         case FFS_OS_DESC_EXT_PROP: {
2391                 struct usb_ext_prop_desc *d = data;
2392                 u32 type, pdl;
2393                 u16 pnl;
2394
2395                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2396                         return -EINVAL;
2397                 length = le32_to_cpu(d->dwSize);
2398                 if (len < length)
2399                         return -EINVAL;
2400                 type = le32_to_cpu(d->dwPropertyDataType);
2401                 if (type < USB_EXT_PROP_UNICODE ||
2402                     type > USB_EXT_PROP_UNICODE_MULTI) {
2403                         pr_vdebug("unsupported os descriptor property type: %d",
2404                                   type);
2405                         return -EINVAL;
2406                 }
2407                 pnl = le16_to_cpu(d->wPropertyNameLength);
2408                 if (length < 14 + pnl) {
2409                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2410                                   length, pnl, type);
2411                         return -EINVAL;
2412                 }
2413                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2414                 if (length != 14 + pnl + pdl) {
2415                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2416                                   length, pnl, pdl, type);
2417                         return -EINVAL;
2418                 }
2419                 ++ffs->ms_os_descs_ext_prop_count;
2420                 /* property name reported to the host as "WCHAR"s */
2421                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2422                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2423         }
2424                 break;
2425         default:
2426                 pr_vdebug("unknown descriptor: %d\n", type);
2427                 return -EINVAL;
2428         }
2429         return length;
2430 }
2431
2432 static int __ffs_data_got_descs(struct ffs_data *ffs,
2433                                 char *const _data, size_t len)
2434 {
2435         char *data = _data, *raw_descs;
2436         unsigned os_descs_count = 0, counts[3], flags;
2437         int ret = -EINVAL, i;
2438         struct ffs_desc_helper helper;
2439
2440         ENTER();
2441
2442         if (get_unaligned_le32(data + 4) != len)
2443                 goto error;
2444
2445         switch (get_unaligned_le32(data)) {
2446         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2447                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2448                 data += 8;
2449                 len  -= 8;
2450                 break;
2451         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2452                 flags = get_unaligned_le32(data + 8);
2453                 ffs->user_flags = flags;
2454                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2455                               FUNCTIONFS_HAS_HS_DESC |
2456                               FUNCTIONFS_HAS_SS_DESC |
2457                               FUNCTIONFS_HAS_MS_OS_DESC |
2458                               FUNCTIONFS_VIRTUAL_ADDR |
2459                               FUNCTIONFS_EVENTFD |
2460                               FUNCTIONFS_ALL_CTRL_RECIP |
2461                               FUNCTIONFS_CONFIG0_SETUP)) {
2462                         ret = -ENOSYS;
2463                         goto error;
2464                 }
2465                 data += 12;
2466                 len  -= 12;
2467                 break;
2468         default:
2469                 goto error;
2470         }
2471
2472         if (flags & FUNCTIONFS_EVENTFD) {
2473                 if (len < 4)
2474                         goto error;
2475                 ffs->ffs_eventfd =
2476                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2477                 if (IS_ERR(ffs->ffs_eventfd)) {
2478                         ret = PTR_ERR(ffs->ffs_eventfd);
2479                         ffs->ffs_eventfd = NULL;
2480                         goto error;
2481                 }
2482                 data += 4;
2483                 len  -= 4;
2484         }
2485
2486         /* Read fs_count, hs_count and ss_count (if present) */
2487         for (i = 0; i < 3; ++i) {
2488                 if (!(flags & (1 << i))) {
2489                         counts[i] = 0;
2490                 } else if (len < 4) {
2491                         goto error;
2492                 } else {
2493                         counts[i] = get_unaligned_le32(data);
2494                         data += 4;
2495                         len  -= 4;
2496                 }
2497         }
2498         if (flags & (1 << i)) {
2499                 if (len < 4) {
2500                         goto error;
2501                 }
2502                 os_descs_count = get_unaligned_le32(data);
2503                 data += 4;
2504                 len -= 4;
2505         };
2506
2507         /* Read descriptors */
2508         raw_descs = data;
2509         helper.ffs = ffs;
2510         for (i = 0; i < 3; ++i) {
2511                 if (!counts[i])
2512                         continue;
2513                 helper.interfaces_count = 0;
2514                 helper.eps_count = 0;
2515                 ret = ffs_do_descs(counts[i], data, len,
2516                                    __ffs_data_do_entity, &helper);
2517                 if (ret < 0)
2518                         goto error;
2519                 if (!ffs->eps_count && !ffs->interfaces_count) {
2520                         ffs->eps_count = helper.eps_count;
2521                         ffs->interfaces_count = helper.interfaces_count;
2522                 } else {
2523                         if (ffs->eps_count != helper.eps_count) {
2524                                 ret = -EINVAL;
2525                                 goto error;
2526                         }
2527                         if (ffs->interfaces_count != helper.interfaces_count) {
2528                                 ret = -EINVAL;
2529                                 goto error;
2530                         }
2531                 }
2532                 data += ret;
2533                 len  -= ret;
2534         }
2535         if (os_descs_count) {
2536                 ret = ffs_do_os_descs(os_descs_count, data, len,
2537                                       __ffs_data_do_os_desc, ffs);
2538                 if (ret < 0)
2539                         goto error;
2540                 data += ret;
2541                 len -= ret;
2542         }
2543
2544         if (raw_descs == data || len) {
2545                 ret = -EINVAL;
2546                 goto error;
2547         }
2548
2549         ffs->raw_descs_data     = _data;
2550         ffs->raw_descs          = raw_descs;
2551         ffs->raw_descs_length   = data - raw_descs;
2552         ffs->fs_descs_count     = counts[0];
2553         ffs->hs_descs_count     = counts[1];
2554         ffs->ss_descs_count     = counts[2];
2555         ffs->ms_os_descs_count  = os_descs_count;
2556
2557         return 0;
2558
2559 error:
2560         kfree(_data);
2561         return ret;
2562 }
2563
2564 static int __ffs_data_got_strings(struct ffs_data *ffs,
2565                                   char *const _data, size_t len)
2566 {
2567         u32 str_count, needed_count, lang_count;
2568         struct usb_gadget_strings **stringtabs, *t;
2569         const char *data = _data;
2570         struct usb_string *s;
2571
2572         ENTER();
2573
2574         if (unlikely(len < 16 ||
2575                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2576                      get_unaligned_le32(data + 4) != len))
2577                 goto error;
2578         str_count  = get_unaligned_le32(data + 8);
2579         lang_count = get_unaligned_le32(data + 12);
2580
2581         /* if one is zero the other must be zero */
2582         if (unlikely(!str_count != !lang_count))
2583                 goto error;
2584
2585         /* Do we have at least as many strings as descriptors need? */
2586         needed_count = ffs->strings_count;
2587         if (unlikely(str_count < needed_count))
2588                 goto error;
2589
2590         /*
2591          * If we don't need any strings just return and free all
2592          * memory.
2593          */
2594         if (!needed_count) {
2595                 kfree(_data);
2596                 return 0;
2597         }
2598
2599         /* Allocate everything in one chunk so there's less maintenance. */
2600         {
2601                 unsigned i = 0;
2602                 vla_group(d);
2603                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2604                         lang_count + 1);
2605                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2606                 vla_item(d, struct usb_string, strings,
2607                         lang_count*(needed_count+1));
2608
2609                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2610
2611                 if (unlikely(!vlabuf)) {
2612                         kfree(_data);
2613                         return -ENOMEM;
2614                 }
2615
2616                 /* Initialize the VLA pointers */
2617                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2618                 t = vla_ptr(vlabuf, d, stringtab);
2619                 i = lang_count;
2620                 do {
2621                         *stringtabs++ = t++;
2622                 } while (--i);
2623                 *stringtabs = NULL;
2624
2625                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2626                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2627                 t = vla_ptr(vlabuf, d, stringtab);
2628                 s = vla_ptr(vlabuf, d, strings);
2629         }
2630
2631         /* For each language */
2632         data += 16;
2633         len -= 16;
2634
2635         do { /* lang_count > 0 so we can use do-while */
2636                 unsigned needed = needed_count;
2637
2638                 if (unlikely(len < 3))
2639                         goto error_free;
2640                 t->language = get_unaligned_le16(data);
2641                 t->strings  = s;
2642                 ++t;
2643
2644                 data += 2;
2645                 len -= 2;
2646
2647                 /* For each string */
2648                 do { /* str_count > 0 so we can use do-while */
2649                         size_t length = strnlen(data, len);
2650
2651                         if (unlikely(length == len))
2652                                 goto error_free;
2653
2654                         /*
2655                          * User may provide more strings then we need,
2656                          * if that's the case we simply ignore the
2657                          * rest
2658                          */
2659                         if (likely(needed)) {
2660                                 /*
2661                                  * s->id will be set while adding
2662                                  * function to configuration so for
2663                                  * now just leave garbage here.
2664                                  */
2665                                 s->s = data;
2666                                 --needed;
2667                                 ++s;
2668                         }
2669
2670                         data += length + 1;
2671                         len -= length + 1;
2672                 } while (--str_count);
2673
2674                 s->id = 0;   /* terminator */
2675                 s->s = NULL;
2676                 ++s;
2677
2678         } while (--lang_count);
2679
2680         /* Some garbage left? */
2681         if (unlikely(len))
2682                 goto error_free;
2683
2684         /* Done! */
2685         ffs->stringtabs = stringtabs;
2686         ffs->raw_strings = _data;
2687
2688         return 0;
2689
2690 error_free:
2691         kfree(stringtabs);
2692 error:
2693         kfree(_data);
2694         return -EINVAL;
2695 }
2696
2697
2698 /* Events handling and management *******************************************/
2699
2700 static void __ffs_event_add(struct ffs_data *ffs,
2701                             enum usb_functionfs_event_type type)
2702 {
2703         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2704         int neg = 0;
2705
2706         /*
2707          * Abort any unhandled setup
2708          *
2709          * We do not need to worry about some cmpxchg() changing value
2710          * of ffs->setup_state without holding the lock because when
2711          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2712          * the source does nothing.
2713          */
2714         if (ffs->setup_state == FFS_SETUP_PENDING)
2715                 ffs->setup_state = FFS_SETUP_CANCELLED;
2716
2717         /*
2718          * Logic of this function guarantees that there are at most four pending
2719          * evens on ffs->ev.types queue.  This is important because the queue
2720          * has space for four elements only and __ffs_ep0_read_events function
2721          * depends on that limit as well.  If more event types are added, those
2722          * limits have to be revisited or guaranteed to still hold.
2723          */
2724         switch (type) {
2725         case FUNCTIONFS_RESUME:
2726                 rem_type2 = FUNCTIONFS_SUSPEND;
2727                 /* FALL THROUGH */
2728         case FUNCTIONFS_SUSPEND:
2729         case FUNCTIONFS_SETUP:
2730                 rem_type1 = type;
2731                 /* Discard all similar events */
2732                 break;
2733
2734         case FUNCTIONFS_BIND:
2735         case FUNCTIONFS_UNBIND:
2736         case FUNCTIONFS_DISABLE:
2737         case FUNCTIONFS_ENABLE:
2738                 /* Discard everything other then power management. */
2739                 rem_type1 = FUNCTIONFS_SUSPEND;
2740                 rem_type2 = FUNCTIONFS_RESUME;
2741                 neg = 1;
2742                 break;
2743
2744         default:
2745                 WARN(1, "%d: unknown event, this should not happen\n", type);
2746                 return;
2747         }
2748
2749         {
2750                 u8 *ev  = ffs->ev.types, *out = ev;
2751                 unsigned n = ffs->ev.count;
2752                 for (; n; --n, ++ev)
2753                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2754                                 *out++ = *ev;
2755                         else
2756                                 pr_vdebug("purging event %d\n", *ev);
2757                 ffs->ev.count = out - ffs->ev.types;
2758         }
2759
2760         pr_vdebug("adding event %d\n", type);
2761         ffs->ev.types[ffs->ev.count++] = type;
2762         wake_up_locked(&ffs->ev.waitq);
2763         if (ffs->ffs_eventfd)
2764                 eventfd_signal(ffs->ffs_eventfd, 1);
2765 }
2766
2767 static void ffs_event_add(struct ffs_data *ffs,
2768                           enum usb_functionfs_event_type type)
2769 {
2770         unsigned long flags;
2771         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2772         __ffs_event_add(ffs, type);
2773         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2774 }
2775
2776 /* Bind/unbind USB function hooks *******************************************/
2777
2778 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2779 {
2780         int i;
2781
2782         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2783                 if (ffs->eps_addrmap[i] == endpoint_address)
2784                         return i;
2785         return -ENOENT;
2786 }
2787
2788 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2789                                     struct usb_descriptor_header *desc,
2790                                     void *priv)
2791 {
2792         struct usb_endpoint_descriptor *ds = (void *)desc;
2793         struct ffs_function *func = priv;
2794         struct ffs_ep *ffs_ep;
2795         unsigned ep_desc_id;
2796         int idx;
2797         static const char *speed_names[] = { "full", "high", "super" };
2798
2799         if (type != FFS_DESCRIPTOR)
2800                 return 0;
2801
2802         /*
2803          * If ss_descriptors is not NULL, we are reading super speed
2804          * descriptors; if hs_descriptors is not NULL, we are reading high
2805          * speed descriptors; otherwise, we are reading full speed
2806          * descriptors.
2807          */
2808         if (func->function.ss_descriptors) {
2809                 ep_desc_id = 2;
2810                 func->function.ss_descriptors[(long)valuep] = desc;
2811         } else if (func->function.hs_descriptors) {
2812                 ep_desc_id = 1;
2813                 func->function.hs_descriptors[(long)valuep] = desc;
2814         } else {
2815                 ep_desc_id = 0;
2816                 func->function.fs_descriptors[(long)valuep]    = desc;
2817         }
2818
2819         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2820                 return 0;
2821
2822         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2823         if (idx < 0)
2824                 return idx;
2825
2826         ffs_ep = func->eps + idx;
2827
2828         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2829                 pr_err("two %sspeed descriptors for EP %d\n",
2830                           speed_names[ep_desc_id],
2831                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2832                 return -EINVAL;
2833         }
2834         ffs_ep->descs[ep_desc_id] = ds;
2835
2836         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2837         if (ffs_ep->ep) {
2838                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2839                 if (!ds->wMaxPacketSize)
2840                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2841         } else {
2842                 struct usb_request *req;
2843                 struct usb_ep *ep;
2844                 u8 bEndpointAddress;
2845                 u16 wMaxPacketSize;
2846
2847                 /*
2848                  * We back up bEndpointAddress because autoconfig overwrites
2849                  * it with physical endpoint address.
2850                  */
2851                 bEndpointAddress = ds->bEndpointAddress;
2852                 /*
2853                  * We back up wMaxPacketSize because autoconfig treats
2854                  * endpoint descriptors as if they were full speed.
2855                  */
2856                 wMaxPacketSize = ds->wMaxPacketSize;
2857                 pr_vdebug("autoconfig\n");
2858                 ep = usb_ep_autoconfig(func->gadget, ds);
2859                 if (unlikely(!ep))
2860                         return -ENOTSUPP;
2861                 ep->driver_data = func->eps + idx;
2862
2863                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2864                 if (unlikely(!req))
2865                         return -ENOMEM;
2866
2867                 ffs_ep->ep  = ep;
2868                 ffs_ep->req = req;
2869                 func->eps_revmap[ds->bEndpointAddress &
2870                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2871                 /*
2872                  * If we use virtual address mapping, we restore
2873                  * original bEndpointAddress value.
2874                  */
2875                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2876                         ds->bEndpointAddress = bEndpointAddress;
2877                 /*
2878                  * Restore wMaxPacketSize which was potentially
2879                  * overwritten by autoconfig.
2880                  */
2881                 ds->wMaxPacketSize = wMaxPacketSize;
2882         }
2883         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2884
2885         return 0;
2886 }
2887
2888 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2889                                    struct usb_descriptor_header *desc,
2890                                    void *priv)
2891 {
2892         struct ffs_function *func = priv;
2893         unsigned idx;
2894         u8 newValue;
2895
2896         switch (type) {
2897         default:
2898         case FFS_DESCRIPTOR:
2899                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2900                 return 0;
2901
2902         case FFS_INTERFACE:
2903                 idx = *valuep;
2904                 if (func->interfaces_nums[idx] < 0) {
2905                         int id = usb_interface_id(func->conf, &func->function);
2906                         if (unlikely(id < 0))
2907                                 return id;
2908                         func->interfaces_nums[idx] = id;
2909                 }
2910                 newValue = func->interfaces_nums[idx];
2911                 break;
2912
2913         case FFS_STRING:
2914                 /* String' IDs are allocated when fsf_data is bound to cdev */
2915                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2916                 break;
2917
2918         case FFS_ENDPOINT:
2919                 /*
2920                  * USB_DT_ENDPOINT are handled in
2921                  * __ffs_func_bind_do_descs().
2922                  */
2923                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2924                         return 0;
2925
2926                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2927                 if (unlikely(!func->eps[idx].ep))
2928                         return -EINVAL;
2929
2930                 {
2931                         struct usb_endpoint_descriptor **descs;
2932                         descs = func->eps[idx].descs;
2933                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2934                 }
2935                 break;
2936         }
2937
2938         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2939         *valuep = newValue;
2940         return 0;
2941 }
2942
2943 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2944                                       struct usb_os_desc_header *h, void *data,
2945                                       unsigned len, void *priv)
2946 {
2947         struct ffs_function *func = priv;
2948         u8 length = 0;
2949
2950         switch (type) {
2951         case FFS_OS_DESC_EXT_COMPAT: {
2952                 struct usb_ext_compat_desc *desc = data;
2953                 struct usb_os_desc_table *t;
2954
2955                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2956                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2957                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2958                        ARRAY_SIZE(desc->CompatibleID) +
2959                        ARRAY_SIZE(desc->SubCompatibleID));
2960                 length = sizeof(*desc);
2961         }
2962                 break;
2963         case FFS_OS_DESC_EXT_PROP: {
2964                 struct usb_ext_prop_desc *desc = data;
2965                 struct usb_os_desc_table *t;
2966                 struct usb_os_desc_ext_prop *ext_prop;
2967                 char *ext_prop_name;
2968                 char *ext_prop_data;
2969
2970                 t = &func->function.os_desc_table[h->interface];
2971                 t->if_id = func->interfaces_nums[h->interface];
2972
2973                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2974                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2975
2976                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2977                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2978                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2979                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2980                 length = ext_prop->name_len + ext_prop->data_len + 14;
2981
2982                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2983                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2984                         ext_prop->name_len;
2985
2986                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2987                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2988                         ext_prop->data_len;
2989                 memcpy(ext_prop_data,
2990                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2991                        ext_prop->data_len);
2992                 /* unicode data reported to the host as "WCHAR"s */
2993                 switch (ext_prop->type) {
2994                 case USB_EXT_PROP_UNICODE:
2995                 case USB_EXT_PROP_UNICODE_ENV:
2996                 case USB_EXT_PROP_UNICODE_LINK:
2997                 case USB_EXT_PROP_UNICODE_MULTI:
2998                         ext_prop->data_len *= 2;
2999                         break;
3000                 }
3001                 ext_prop->data = ext_prop_data;
3002
3003                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3004                        ext_prop->name_len);
3005                 /* property name reported to the host as "WCHAR"s */
3006                 ext_prop->name_len *= 2;
3007                 ext_prop->name = ext_prop_name;
3008
3009                 t->os_desc->ext_prop_len +=
3010                         ext_prop->name_len + ext_prop->data_len + 14;
3011                 ++t->os_desc->ext_prop_count;
3012                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3013         }
3014                 break;
3015         default:
3016                 pr_vdebug("unknown descriptor: %d\n", type);
3017         }
3018
3019         return length;
3020 }
3021
3022 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3023                                                 struct usb_configuration *c)
3024 {
3025         struct ffs_function *func = ffs_func_from_usb(f);
3026         struct f_fs_opts *ffs_opts =
3027                 container_of(f->fi, struct f_fs_opts, func_inst);
3028         int ret;
3029
3030         ENTER();
3031
3032         /*
3033          * Legacy gadget triggers binding in functionfs_ready_callback,
3034          * which already uses locking; taking the same lock here would
3035          * cause a deadlock.
3036          *
3037          * Configfs-enabled gadgets however do need ffs_dev_lock.
3038          */
3039         if (!ffs_opts->no_configfs)
3040                 ffs_dev_lock();
3041         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3042         func->ffs = ffs_opts->dev->ffs_data;
3043         if (!ffs_opts->no_configfs)
3044                 ffs_dev_unlock();
3045         if (ret)
3046                 return ERR_PTR(ret);
3047
3048         func->conf = c;
3049         func->gadget = c->cdev->gadget;
3050
3051         /*
3052          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3053          * configurations are bound in sequence with list_for_each_entry,
3054          * in each configuration its functions are bound in sequence
3055          * with list_for_each_entry, so we assume no race condition
3056          * with regard to ffs_opts->bound access
3057          */
3058         if (!ffs_opts->refcnt) {
3059                 ret = functionfs_bind(func->ffs, c->cdev);
3060                 if (ret)
3061                         return ERR_PTR(ret);
3062         }
3063         ffs_opts->refcnt++;
3064         func->function.strings = func->ffs->stringtabs;
3065
3066         return ffs_opts;
3067 }
3068
3069 static int _ffs_func_bind(struct usb_configuration *c,
3070                           struct usb_function *f)
3071 {
3072         struct ffs_function *func = ffs_func_from_usb(f);
3073         struct ffs_data *ffs = func->ffs;
3074
3075         const int full = !!func->ffs->fs_descs_count;
3076         const int high = !!func->ffs->hs_descs_count;
3077         const int super = !!func->ffs->ss_descs_count;
3078
3079         int fs_len, hs_len, ss_len, ret, i;
3080         struct ffs_ep *eps_ptr;
3081
3082         /* Make it a single chunk, less management later on */
3083         vla_group(d);
3084         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3085         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3086                 full ? ffs->fs_descs_count + 1 : 0);
3087         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3088                 high ? ffs->hs_descs_count + 1 : 0);
3089         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3090                 super ? ffs->ss_descs_count + 1 : 0);
3091         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3092         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3093                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3094         vla_item_with_sz(d, char[16], ext_compat,
3095                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3096         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3097                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3098         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3099                          ffs->ms_os_descs_ext_prop_count);
3100         vla_item_with_sz(d, char, ext_prop_name,
3101                          ffs->ms_os_descs_ext_prop_name_len);
3102         vla_item_with_sz(d, char, ext_prop_data,
3103                          ffs->ms_os_descs_ext_prop_data_len);
3104         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3105         char *vlabuf;
3106
3107         ENTER();
3108
3109         /* Has descriptors only for speeds gadget does not support */
3110         if (unlikely(!(full | high | super)))
3111                 return -ENOTSUPP;
3112
3113         /* Allocate a single chunk, less management later on */
3114         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3115         if (unlikely(!vlabuf))
3116                 return -ENOMEM;
3117
3118         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3119         ffs->ms_os_descs_ext_prop_name_avail =
3120                 vla_ptr(vlabuf, d, ext_prop_name);
3121         ffs->ms_os_descs_ext_prop_data_avail =
3122                 vla_ptr(vlabuf, d, ext_prop_data);
3123
3124         /* Copy descriptors  */
3125         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3126                ffs->raw_descs_length);
3127
3128         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3129         eps_ptr = vla_ptr(vlabuf, d, eps);
3130         for (i = 0; i < ffs->eps_count; i++)
3131                 eps_ptr[i].num = -1;
3132
3133         /* Save pointers
3134          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3135         */
3136         func->eps             = vla_ptr(vlabuf, d, eps);
3137         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3138
3139         /*
3140          * Go through all the endpoint descriptors and allocate
3141          * endpoints first, so that later we can rewrite the endpoint
3142          * numbers without worrying that it may be described later on.
3143          */
3144         if (likely(full)) {
3145                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3146                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3147                                       vla_ptr(vlabuf, d, raw_descs),
3148                                       d_raw_descs__sz,
3149                                       __ffs_func_bind_do_descs, func);
3150                 if (unlikely(fs_len < 0)) {
3151                         ret = fs_len;
3152                         goto error;
3153                 }
3154         } else {
3155                 fs_len = 0;
3156         }
3157
3158         if (likely(high)) {
3159                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3160                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3161                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3162                                       d_raw_descs__sz - fs_len,
3163                                       __ffs_func_bind_do_descs, func);
3164                 if (unlikely(hs_len < 0)) {
3165                         ret = hs_len;
3166                         goto error;
3167                 }
3168         } else {
3169                 hs_len = 0;
3170         }
3171
3172         if (likely(super)) {
3173                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3174                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3175                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3176                                 d_raw_descs__sz - fs_len - hs_len,
3177                                 __ffs_func_bind_do_descs, func);
3178                 if (unlikely(ss_len < 0)) {
3179                         ret = ss_len;
3180                         goto error;
3181                 }
3182         } else {
3183                 ss_len = 0;
3184         }
3185
3186         /*
3187          * Now handle interface numbers allocation and interface and
3188          * endpoint numbers rewriting.  We can do that in one go
3189          * now.
3190          */
3191         ret = ffs_do_descs(ffs->fs_descs_count +
3192                            (high ? ffs->hs_descs_count : 0) +
3193                            (super ? ffs->ss_descs_count : 0),
3194                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3195                            __ffs_func_bind_do_nums, func);
3196         if (unlikely(ret < 0))
3197                 goto error;
3198
3199         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3200         if (c->cdev->use_os_string) {
3201                 for (i = 0; i < ffs->interfaces_count; ++i) {
3202                         struct usb_os_desc *desc;
3203
3204                         desc = func->function.os_desc_table[i].os_desc =
3205                                 vla_ptr(vlabuf, d, os_desc) +
3206                                 i * sizeof(struct usb_os_desc);
3207                         desc->ext_compat_id =
3208                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3209                         INIT_LIST_HEAD(&desc->ext_prop);
3210                 }
3211                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3212                                       vla_ptr(vlabuf, d, raw_descs) +
3213                                       fs_len + hs_len + ss_len,
3214                                       d_raw_descs__sz - fs_len - hs_len -
3215                                       ss_len,
3216                                       __ffs_func_bind_do_os_desc, func);
3217                 if (unlikely(ret < 0))
3218                         goto error;
3219         }
3220         func->function.os_desc_n =
3221                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3222
3223         /* And we're done */
3224         ffs_event_add(ffs, FUNCTIONFS_BIND);
3225         return 0;
3226
3227 error:
3228         /* XXX Do we need to release all claimed endpoints here? */
3229         return ret;
3230 }
3231
3232 static int ffs_func_bind(struct usb_configuration *c,
3233                          struct usb_function *f)
3234 {
3235         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3236         struct ffs_function *func = ffs_func_from_usb(f);
3237         int ret;
3238
3239         if (IS_ERR(ffs_opts))
3240                 return PTR_ERR(ffs_opts);
3241
3242         ret = _ffs_func_bind(c, f);
3243         if (ret && !--ffs_opts->refcnt)
3244                 functionfs_unbind(func->ffs);
3245
3246         return ret;
3247 }
3248
3249
3250 /* Other USB function hooks *************************************************/
3251
3252 static void ffs_reset_work(struct work_struct *work)
3253 {
3254         struct ffs_data *ffs = container_of(work,
3255                 struct ffs_data, reset_work);
3256         ffs_data_reset(ffs);
3257 }
3258
3259 static int ffs_func_set_alt(struct usb_function *f,
3260                             unsigned interface, unsigned alt)
3261 {
3262         struct ffs_function *func = ffs_func_from_usb(f);
3263         struct ffs_data *ffs = func->ffs;
3264         int ret = 0, intf;
3265
3266         if (alt != (unsigned)-1) {
3267                 intf = ffs_func_revmap_intf(func, interface);
3268                 if (unlikely(intf < 0))
3269                         return intf;
3270         }
3271
3272         if (ffs->func)
3273                 ffs_func_eps_disable(ffs->func);
3274
3275         if (ffs->state == FFS_DEACTIVATED) {
3276                 ffs->state = FFS_CLOSING;
3277                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3278                 schedule_work(&ffs->reset_work);
3279                 return -ENODEV;
3280         }
3281
3282         if (ffs->state != FFS_ACTIVE)
3283                 return -ENODEV;
3284
3285         if (alt == (unsigned)-1) {
3286                 ffs->func = NULL;
3287                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3288                 return 0;
3289         }
3290
3291         ffs->func = func;
3292         ret = ffs_func_eps_enable(func);
3293         if (likely(ret >= 0))
3294                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3295         return ret;
3296 }
3297
3298 static void ffs_func_disable(struct usb_function *f)
3299 {
3300         ffs_func_set_alt(f, 0, (unsigned)-1);
3301 }
3302
3303 static int ffs_func_setup(struct usb_function *f,
3304                           const struct usb_ctrlrequest *creq)
3305 {
3306         struct ffs_function *func = ffs_func_from_usb(f);
3307         struct ffs_data *ffs = func->ffs;
3308         unsigned long flags;
3309         int ret;
3310
3311         ENTER();
3312
3313         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3314         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3315         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3316         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3317         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3318
3319         /*
3320          * Most requests directed to interface go through here
3321          * (notable exceptions are set/get interface) so we need to
3322          * handle them.  All other either handled by composite or
3323          * passed to usb_configuration->setup() (if one is set).  No
3324          * matter, we will handle requests directed to endpoint here
3325          * as well (as it's straightforward).  Other request recipient
3326          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3327          * is being used.
3328          */
3329         if (ffs->state != FFS_ACTIVE)
3330                 return -ENODEV;
3331
3332         switch (creq->bRequestType & USB_RECIP_MASK) {
3333         case USB_RECIP_INTERFACE:
3334                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3335                 if (unlikely(ret < 0))
3336                         return ret;
3337                 break;
3338
3339         case USB_RECIP_ENDPOINT:
3340                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3341                 if (unlikely(ret < 0))
3342                         return ret;
3343                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3344                         ret = func->ffs->eps_addrmap[ret];
3345                 break;
3346
3347         default:
3348                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3349                         ret = le16_to_cpu(creq->wIndex);
3350                 else
3351                         return -EOPNOTSUPP;
3352         }
3353
3354         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3355         ffs->ev.setup = *creq;
3356         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3357         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3358         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3359
3360         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3361 }
3362
3363 static bool ffs_func_req_match(struct usb_function *f,
3364                                const struct usb_ctrlrequest *creq,
3365                                bool config0)
3366 {
3367         struct ffs_function *func = ffs_func_from_usb(f);
3368
3369         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3370                 return false;
3371
3372         switch (creq->bRequestType & USB_RECIP_MASK) {
3373         case USB_RECIP_INTERFACE:
3374                 return (ffs_func_revmap_intf(func,
3375                                              le16_to_cpu(creq->wIndex)) >= 0);
3376         case USB_RECIP_ENDPOINT:
3377                 return (ffs_func_revmap_ep(func,
3378                                            le16_to_cpu(creq->wIndex)) >= 0);
3379         default:
3380                 return (bool) (func->ffs->user_flags &
3381                                FUNCTIONFS_ALL_CTRL_RECIP);
3382         }
3383 }
3384
3385 static void ffs_func_suspend(struct usb_function *f)
3386 {
3387         ENTER();
3388         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3389 }
3390
3391 static void ffs_func_resume(struct usb_function *f)
3392 {
3393         ENTER();
3394         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3395 }
3396
3397
3398 /* Endpoint and interface numbers reverse mapping ***************************/
3399
3400 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3401 {
3402         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3403         return num ? num : -EDOM;
3404 }
3405
3406 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3407 {
3408         short *nums = func->interfaces_nums;
3409         unsigned count = func->ffs->interfaces_count;
3410
3411         for (; count; --count, ++nums) {
3412                 if (*nums >= 0 && *nums == intf)
3413                         return nums - func->interfaces_nums;
3414         }
3415
3416         return -EDOM;
3417 }
3418
3419
3420 /* Devices management *******************************************************/
3421
3422 static LIST_HEAD(ffs_devices);
3423
3424 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3425 {
3426         struct ffs_dev *dev;
3427
3428         if (!name)
3429                 return NULL;
3430
3431         list_for_each_entry(dev, &ffs_devices, entry) {
3432                 if (strcmp(dev->name, name) == 0)
3433                         return dev;
3434         }
3435
3436         return NULL;
3437 }
3438
3439 /*
3440  * ffs_lock must be taken by the caller of this function
3441  */
3442 static struct ffs_dev *_ffs_get_single_dev(void)
3443 {
3444         struct ffs_dev *dev;
3445
3446         if (list_is_singular(&ffs_devices)) {
3447                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3448                 if (dev->single)
3449                         return dev;
3450         }
3451
3452         return NULL;
3453 }
3454
3455 /*
3456  * ffs_lock must be taken by the caller of this function
3457  */
3458 static struct ffs_dev *_ffs_find_dev(const char *name)
3459 {
3460         struct ffs_dev *dev;
3461
3462         dev = _ffs_get_single_dev();
3463         if (dev)
3464                 return dev;
3465
3466         return _ffs_do_find_dev(name);
3467 }
3468
3469 /* Configfs support *********************************************************/
3470
3471 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3472 {
3473         return container_of(to_config_group(item), struct f_fs_opts,
3474                             func_inst.group);
3475 }
3476
3477 static void ffs_attr_release(struct config_item *item)
3478 {
3479         struct f_fs_opts *opts = to_ffs_opts(item);
3480
3481         usb_put_function_instance(&opts->func_inst);
3482 }
3483
3484 static struct configfs_item_operations ffs_item_ops = {
3485         .release        = ffs_attr_release,
3486 };
3487
3488 static const struct config_item_type ffs_func_type = {
3489         .ct_item_ops    = &ffs_item_ops,
3490         .ct_owner       = THIS_MODULE,
3491 };
3492
3493
3494 /* Function registration interface ******************************************/
3495
3496 static void ffs_free_inst(struct usb_function_instance *f)
3497 {
3498         struct f_fs_opts *opts;
3499
3500         opts = to_f_fs_opts(f);
3501         ffs_dev_lock();
3502         _ffs_free_dev(opts->dev);
3503         ffs_dev_unlock();
3504         kfree(opts);
3505 }
3506
3507 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3508 {
3509         if (strlen(name) >= sizeof_field(struct ffs_dev, name))
3510                 return -ENAMETOOLONG;
3511         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3512 }
3513
3514 static struct usb_function_instance *ffs_alloc_inst(void)
3515 {
3516         struct f_fs_opts *opts;
3517         struct ffs_dev *dev;
3518
3519         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3520         if (!opts)
3521                 return ERR_PTR(-ENOMEM);
3522
3523         opts->func_inst.set_inst_name = ffs_set_inst_name;
3524         opts->func_inst.free_func_inst = ffs_free_inst;
3525         ffs_dev_lock();
3526         dev = _ffs_alloc_dev();
3527         ffs_dev_unlock();
3528         if (IS_ERR(dev)) {
3529                 kfree(opts);
3530                 return ERR_CAST(dev);
3531         }
3532         opts->dev = dev;
3533         dev->opts = opts;
3534
3535         config_group_init_type_name(&opts->func_inst.group, "",
3536                                     &ffs_func_type);
3537         return &opts->func_inst;
3538 }
3539
3540 static void ffs_free(struct usb_function *f)
3541 {
3542         kfree(ffs_func_from_usb(f));
3543 }
3544
3545 static void ffs_func_unbind(struct usb_configuration *c,
3546                             struct usb_function *f)
3547 {
3548         struct ffs_function *func = ffs_func_from_usb(f);
3549         struct ffs_data *ffs = func->ffs;
3550         struct f_fs_opts *opts =
3551                 container_of(f->fi, struct f_fs_opts, func_inst);
3552         struct ffs_ep *ep = func->eps;
3553         unsigned count = ffs->eps_count;
3554         unsigned long flags;
3555
3556         ENTER();
3557         if (ffs->func == func) {
3558                 ffs_func_eps_disable(func);
3559                 ffs->func = NULL;
3560         }
3561
3562         if (!--opts->refcnt)
3563                 functionfs_unbind(ffs);
3564
3565         /* cleanup after autoconfig */
3566         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3567         while (count--) {
3568                 if (ep->ep && ep->req)
3569                         usb_ep_free_request(ep->ep, ep->req);
3570                 ep->req = NULL;
3571                 ++ep;
3572         }
3573         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3574         kfree(func->eps);
3575         func->eps = NULL;
3576         /*
3577          * eps, descriptors and interfaces_nums are allocated in the
3578          * same chunk so only one free is required.
3579          */
3580         func->function.fs_descriptors = NULL;
3581         func->function.hs_descriptors = NULL;
3582         func->function.ss_descriptors = NULL;
3583         func->interfaces_nums = NULL;
3584
3585         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3586 }
3587
3588 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3589 {
3590         struct ffs_function *func;
3591
3592         ENTER();
3593
3594         func = kzalloc(sizeof(*func), GFP_KERNEL);
3595         if (unlikely(!func))
3596                 return ERR_PTR(-ENOMEM);
3597
3598         func->function.name    = "Function FS Gadget";
3599
3600         func->function.bind    = ffs_func_bind;
3601         func->function.unbind  = ffs_func_unbind;
3602         func->function.set_alt = ffs_func_set_alt;
3603         func->function.disable = ffs_func_disable;
3604         func->function.setup   = ffs_func_setup;
3605         func->function.req_match = ffs_func_req_match;
3606         func->function.suspend = ffs_func_suspend;
3607         func->function.resume  = ffs_func_resume;
3608         func->function.free_func = ffs_free;
3609
3610         return &func->function;
3611 }
3612
3613 /*
3614  * ffs_lock must be taken by the caller of this function
3615  */
3616 static struct ffs_dev *_ffs_alloc_dev(void)
3617 {
3618         struct ffs_dev *dev;
3619         int ret;
3620
3621         if (_ffs_get_single_dev())
3622                         return ERR_PTR(-EBUSY);
3623
3624         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3625         if (!dev)
3626                 return ERR_PTR(-ENOMEM);
3627
3628         if (list_empty(&ffs_devices)) {
3629                 ret = functionfs_init();
3630                 if (ret) {
3631                         kfree(dev);
3632                         return ERR_PTR(ret);
3633                 }
3634         }
3635
3636         list_add(&dev->entry, &ffs_devices);
3637
3638         return dev;
3639 }
3640
3641 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3642 {
3643         struct ffs_dev *existing;
3644         int ret = 0;
3645
3646         ffs_dev_lock();
3647
3648         existing = _ffs_do_find_dev(name);
3649         if (!existing)
3650                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3651         else if (existing != dev)
3652                 ret = -EBUSY;
3653
3654         ffs_dev_unlock();
3655
3656         return ret;
3657 }
3658 EXPORT_SYMBOL_GPL(ffs_name_dev);
3659
3660 int ffs_single_dev(struct ffs_dev *dev)
3661 {
3662         int ret;
3663
3664         ret = 0;
3665         ffs_dev_lock();
3666
3667         if (!list_is_singular(&ffs_devices))
3668                 ret = -EBUSY;
3669         else
3670                 dev->single = true;
3671
3672         ffs_dev_unlock();
3673         return ret;
3674 }
3675 EXPORT_SYMBOL_GPL(ffs_single_dev);
3676
3677 /*
3678  * ffs_lock must be taken by the caller of this function
3679  */
3680 static void _ffs_free_dev(struct ffs_dev *dev)
3681 {
3682         list_del(&dev->entry);
3683
3684         /* Clear the private_data pointer to stop incorrect dev access */
3685         if (dev->ffs_data)
3686                 dev->ffs_data->private_data = NULL;
3687
3688         kfree(dev);
3689         if (list_empty(&ffs_devices))
3690                 functionfs_cleanup();
3691 }
3692
3693 static void *ffs_acquire_dev(const char *dev_name)
3694 {
3695         struct ffs_dev *ffs_dev;
3696
3697         ENTER();
3698         ffs_dev_lock();
3699
3700         ffs_dev = _ffs_find_dev(dev_name);
3701         if (!ffs_dev)
3702                 ffs_dev = ERR_PTR(-ENOENT);
3703         else if (ffs_dev->mounted)
3704                 ffs_dev = ERR_PTR(-EBUSY);
3705         else if (ffs_dev->ffs_acquire_dev_callback &&
3706             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3707                 ffs_dev = ERR_PTR(-ENOENT);
3708         else
3709                 ffs_dev->mounted = true;
3710
3711         ffs_dev_unlock();
3712         return ffs_dev;
3713 }
3714
3715 static void ffs_release_dev(struct ffs_data *ffs_data)
3716 {
3717         struct ffs_dev *ffs_dev;
3718
3719         ENTER();
3720         ffs_dev_lock();
3721
3722         ffs_dev = ffs_data->private_data;
3723         if (ffs_dev) {
3724                 ffs_dev->mounted = false;
3725
3726                 if (ffs_dev->ffs_release_dev_callback)
3727                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3728         }
3729
3730         ffs_dev_unlock();
3731 }
3732
3733 static int ffs_ready(struct ffs_data *ffs)
3734 {
3735         struct ffs_dev *ffs_obj;
3736         int ret = 0;
3737
3738         ENTER();
3739         ffs_dev_lock();
3740
3741         ffs_obj = ffs->private_data;
3742         if (!ffs_obj) {
3743                 ret = -EINVAL;
3744                 goto done;
3745         }
3746         if (WARN_ON(ffs_obj->desc_ready)) {
3747                 ret = -EBUSY;
3748                 goto done;
3749         }
3750
3751         ffs_obj->desc_ready = true;
3752         ffs_obj->ffs_data = ffs;
3753
3754         if (ffs_obj->ffs_ready_callback) {
3755                 ret = ffs_obj->ffs_ready_callback(ffs);
3756                 if (ret)
3757                         goto done;
3758         }
3759
3760         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3761 done:
3762         ffs_dev_unlock();
3763         return ret;
3764 }
3765
3766 static void ffs_closed(struct ffs_data *ffs)
3767 {
3768         struct ffs_dev *ffs_obj;
3769         struct f_fs_opts *opts;
3770         struct config_item *ci;
3771
3772         ENTER();
3773         ffs_dev_lock();
3774
3775         ffs_obj = ffs->private_data;
3776         if (!ffs_obj)
3777                 goto done;
3778
3779         ffs_obj->desc_ready = false;
3780         ffs_obj->ffs_data = NULL;
3781
3782         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3783             ffs_obj->ffs_closed_callback)
3784                 ffs_obj->ffs_closed_callback(ffs);
3785
3786         if (ffs_obj->opts)
3787                 opts = ffs_obj->opts;
3788         else
3789                 goto done;
3790
3791         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3792             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3793                 goto done;
3794
3795         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3796         ffs_dev_unlock();
3797
3798         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3799                 unregister_gadget_item(ci);
3800         return;
3801 done:
3802         ffs_dev_unlock();
3803 }
3804
3805 /* Misc helper functions ****************************************************/
3806
3807 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3808 {
3809         return nonblock
3810                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3811                 : mutex_lock_interruptible(mutex);
3812 }
3813
3814 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3815 {
3816         char *data;
3817
3818         if (unlikely(!len))
3819                 return NULL;
3820
3821         data = kmalloc(len, GFP_KERNEL);
3822         if (unlikely(!data))
3823                 return ERR_PTR(-ENOMEM);
3824
3825         if (unlikely(copy_from_user(data, buf, len))) {
3826                 kfree(data);
3827                 return ERR_PTR(-EFAULT);
3828         }
3829
3830         pr_vdebug("Buffer from user space:\n");
3831         ffs_dump_mem("", data, len);
3832
3833         return data;
3834 }
3835
3836 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3837 MODULE_LICENSE("GPL");
3838 MODULE_AUTHOR("Michal Nazarewicz");