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         unsigned long flags;
1166         int value;
1167
1168         ENTER();
1169
1170         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1171
1172         if (likely(io_data && io_data->ep && io_data->req))
1173                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1174         else
1175                 value = -EINVAL;
1176
1177         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1178
1179         return value;
1180 }
1181
1182 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1183 {
1184         struct ffs_io_data io_data, *p = &io_data;
1185         ssize_t res;
1186
1187         ENTER();
1188
1189         if (!is_sync_kiocb(kiocb)) {
1190                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1191                 if (unlikely(!p))
1192                         return -ENOMEM;
1193                 p->aio = true;
1194         } else {
1195                 memset(p, 0, sizeof(*p));
1196                 p->aio = false;
1197         }
1198
1199         p->read = false;
1200         p->kiocb = kiocb;
1201         p->data = *from;
1202         p->mm = current->mm;
1203
1204         kiocb->private = p;
1205
1206         if (p->aio)
1207                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1208
1209         res = ffs_epfile_io(kiocb->ki_filp, p);
1210         if (res == -EIOCBQUEUED)
1211                 return res;
1212         if (p->aio)
1213                 kfree(p);
1214         else
1215                 *from = p->data;
1216         return res;
1217 }
1218
1219 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1220 {
1221         struct ffs_io_data io_data, *p = &io_data;
1222         ssize_t res;
1223
1224         ENTER();
1225
1226         if (!is_sync_kiocb(kiocb)) {
1227                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1228                 if (unlikely(!p))
1229                         return -ENOMEM;
1230                 p->aio = true;
1231         } else {
1232                 memset(p, 0, sizeof(*p));
1233                 p->aio = false;
1234         }
1235
1236         p->read = true;
1237         p->kiocb = kiocb;
1238         if (p->aio) {
1239                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1240                 if (!p->to_free) {
1241                         kfree(p);
1242                         return -ENOMEM;
1243                 }
1244         } else {
1245                 p->data = *to;
1246                 p->to_free = NULL;
1247         }
1248         p->mm = current->mm;
1249
1250         kiocb->private = p;
1251
1252         if (p->aio)
1253                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1254
1255         res = ffs_epfile_io(kiocb->ki_filp, p);
1256         if (res == -EIOCBQUEUED)
1257                 return res;
1258
1259         if (p->aio) {
1260                 kfree(p->to_free);
1261                 kfree(p);
1262         } else {
1263                 *to = p->data;
1264         }
1265         return res;
1266 }
1267
1268 static int
1269 ffs_epfile_release(struct inode *inode, struct file *file)
1270 {
1271         struct ffs_epfile *epfile = inode->i_private;
1272
1273         ENTER();
1274
1275         __ffs_epfile_read_buffer_free(epfile);
1276         ffs_data_closed(epfile->ffs);
1277
1278         return 0;
1279 }
1280
1281 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1282                              unsigned long value)
1283 {
1284         struct ffs_epfile *epfile = file->private_data;
1285         struct ffs_ep *ep;
1286         int ret;
1287
1288         ENTER();
1289
1290         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1291                 return -ENODEV;
1292
1293         /* Wait for endpoint to be enabled */
1294         ep = epfile->ep;
1295         if (!ep) {
1296                 if (file->f_flags & O_NONBLOCK)
1297                         return -EAGAIN;
1298
1299                 ret = wait_event_interruptible(
1300                                 epfile->ffs->wait, (ep = epfile->ep));
1301                 if (ret)
1302                         return -EINTR;
1303         }
1304
1305         spin_lock_irq(&epfile->ffs->eps_lock);
1306
1307         /* In the meantime, endpoint got disabled or changed. */
1308         if (epfile->ep != ep) {
1309                 spin_unlock_irq(&epfile->ffs->eps_lock);
1310                 return -ESHUTDOWN;
1311         }
1312
1313         switch (code) {
1314         case FUNCTIONFS_FIFO_STATUS:
1315                 ret = usb_ep_fifo_status(epfile->ep->ep);
1316                 break;
1317         case FUNCTIONFS_FIFO_FLUSH:
1318                 usb_ep_fifo_flush(epfile->ep->ep);
1319                 ret = 0;
1320                 break;
1321         case FUNCTIONFS_CLEAR_HALT:
1322                 ret = usb_ep_clear_halt(epfile->ep->ep);
1323                 break;
1324         case FUNCTIONFS_ENDPOINT_REVMAP:
1325                 ret = epfile->ep->num;
1326                 break;
1327         case FUNCTIONFS_ENDPOINT_DESC:
1328         {
1329                 int desc_idx;
1330                 struct usb_endpoint_descriptor *desc;
1331
1332                 switch (epfile->ffs->gadget->speed) {
1333                 case USB_SPEED_SUPER:
1334                         desc_idx = 2;
1335                         break;
1336                 case USB_SPEED_HIGH:
1337                         desc_idx = 1;
1338                         break;
1339                 default:
1340                         desc_idx = 0;
1341                 }
1342                 desc = epfile->ep->descs[desc_idx];
1343
1344                 spin_unlock_irq(&epfile->ffs->eps_lock);
1345                 ret = copy_to_user((void __user *)value, desc, desc->bLength);
1346                 if (ret)
1347                         ret = -EFAULT;
1348                 return ret;
1349         }
1350         default:
1351                 ret = -ENOTTY;
1352         }
1353         spin_unlock_irq(&epfile->ffs->eps_lock);
1354
1355         return ret;
1356 }
1357
1358 static const struct file_operations ffs_epfile_operations = {
1359         .llseek =       no_llseek,
1360
1361         .open =         ffs_epfile_open,
1362         .write_iter =   ffs_epfile_write_iter,
1363         .read_iter =    ffs_epfile_read_iter,
1364         .release =      ffs_epfile_release,
1365         .unlocked_ioctl =       ffs_epfile_ioctl,
1366         .compat_ioctl = compat_ptr_ioctl,
1367 };
1368
1369
1370 /* File system and super block operations ***********************************/
1371
1372 /*
1373  * Mounting the file system creates a controller file, used first for
1374  * function configuration then later for event monitoring.
1375  */
1376
1377 static struct inode *__must_check
1378 ffs_sb_make_inode(struct super_block *sb, void *data,
1379                   const struct file_operations *fops,
1380                   const struct inode_operations *iops,
1381                   struct ffs_file_perms *perms)
1382 {
1383         struct inode *inode;
1384
1385         ENTER();
1386
1387         inode = new_inode(sb);
1388
1389         if (likely(inode)) {
1390                 struct timespec64 ts = current_time(inode);
1391
1392                 inode->i_ino     = get_next_ino();
1393                 inode->i_mode    = perms->mode;
1394                 inode->i_uid     = perms->uid;
1395                 inode->i_gid     = perms->gid;
1396                 inode->i_atime   = ts;
1397                 inode->i_mtime   = ts;
1398                 inode->i_ctime   = ts;
1399                 inode->i_private = data;
1400                 if (fops)
1401                         inode->i_fop = fops;
1402                 if (iops)
1403                         inode->i_op  = iops;
1404         }
1405
1406         return inode;
1407 }
1408
1409 /* Create "regular" file */
1410 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1411                                         const char *name, void *data,
1412                                         const struct file_operations *fops)
1413 {
1414         struct ffs_data *ffs = sb->s_fs_info;
1415         struct dentry   *dentry;
1416         struct inode    *inode;
1417
1418         ENTER();
1419
1420         dentry = d_alloc_name(sb->s_root, name);
1421         if (unlikely(!dentry))
1422                 return NULL;
1423
1424         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1425         if (unlikely(!inode)) {
1426                 dput(dentry);
1427                 return NULL;
1428         }
1429
1430         d_add(dentry, inode);
1431         return dentry;
1432 }
1433
1434 /* Super block */
1435 static const struct super_operations ffs_sb_operations = {
1436         .statfs =       simple_statfs,
1437         .drop_inode =   generic_delete_inode,
1438 };
1439
1440 struct ffs_sb_fill_data {
1441         struct ffs_file_perms perms;
1442         umode_t root_mode;
1443         const char *dev_name;
1444         bool no_disconnect;
1445         struct ffs_data *ffs_data;
1446 };
1447
1448 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1449 {
1450         struct ffs_sb_fill_data *data = fc->fs_private;
1451         struct inode    *inode;
1452         struct ffs_data *ffs = data->ffs_data;
1453
1454         ENTER();
1455
1456         ffs->sb              = sb;
1457         data->ffs_data       = NULL;
1458         sb->s_fs_info        = ffs;
1459         sb->s_blocksize      = PAGE_SIZE;
1460         sb->s_blocksize_bits = PAGE_SHIFT;
1461         sb->s_magic          = FUNCTIONFS_MAGIC;
1462         sb->s_op             = &ffs_sb_operations;
1463         sb->s_time_gran      = 1;
1464
1465         /* Root inode */
1466         data->perms.mode = data->root_mode;
1467         inode = ffs_sb_make_inode(sb, NULL,
1468                                   &simple_dir_operations,
1469                                   &simple_dir_inode_operations,
1470                                   &data->perms);
1471         sb->s_root = d_make_root(inode);
1472         if (unlikely(!sb->s_root))
1473                 return -ENOMEM;
1474
1475         /* EP0 file */
1476         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1477                                          &ffs_ep0_operations)))
1478                 return -ENOMEM;
1479
1480         return 0;
1481 }
1482
1483 enum {
1484         Opt_no_disconnect,
1485         Opt_rmode,
1486         Opt_fmode,
1487         Opt_mode,
1488         Opt_uid,
1489         Opt_gid,
1490 };
1491
1492 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1493         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1494         fsparam_u32     ("rmode",               Opt_rmode),
1495         fsparam_u32     ("fmode",               Opt_fmode),
1496         fsparam_u32     ("mode",                Opt_mode),
1497         fsparam_u32     ("uid",                 Opt_uid),
1498         fsparam_u32     ("gid",                 Opt_gid),
1499         {}
1500 };
1501
1502 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1503 {
1504         struct ffs_sb_fill_data *data = fc->fs_private;
1505         struct fs_parse_result result;
1506         int opt;
1507
1508         ENTER();
1509
1510         opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1511         if (opt < 0)
1512                 return opt;
1513
1514         switch (opt) {
1515         case Opt_no_disconnect:
1516                 data->no_disconnect = result.boolean;
1517                 break;
1518         case Opt_rmode:
1519                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1520                 break;
1521         case Opt_fmode:
1522                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1523                 break;
1524         case Opt_mode:
1525                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1526                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1527                 break;
1528
1529         case Opt_uid:
1530                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1531                 if (!uid_valid(data->perms.uid))
1532                         goto unmapped_value;
1533                 break;
1534         case Opt_gid:
1535                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1536                 if (!gid_valid(data->perms.gid))
1537                         goto unmapped_value;
1538                 break;
1539
1540         default:
1541                 return -ENOPARAM;
1542         }
1543
1544         return 0;
1545
1546 unmapped_value:
1547         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1548 }
1549
1550 /*
1551  * Set up the superblock for a mount.
1552  */
1553 static int ffs_fs_get_tree(struct fs_context *fc)
1554 {
1555         struct ffs_sb_fill_data *ctx = fc->fs_private;
1556         void *ffs_dev;
1557         struct ffs_data *ffs;
1558
1559         ENTER();
1560
1561         if (!fc->source)
1562                 return invalf(fc, "No source specified");
1563
1564         ffs = ffs_data_new(fc->source);
1565         if (unlikely(!ffs))
1566                 return -ENOMEM;
1567         ffs->file_perms = ctx->perms;
1568         ffs->no_disconnect = ctx->no_disconnect;
1569
1570         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1571         if (unlikely(!ffs->dev_name)) {
1572                 ffs_data_put(ffs);
1573                 return -ENOMEM;
1574         }
1575
1576         ffs_dev = ffs_acquire_dev(ffs->dev_name);
1577         if (IS_ERR(ffs_dev)) {
1578                 ffs_data_put(ffs);
1579                 return PTR_ERR(ffs_dev);
1580         }
1581
1582         ffs->private_data = ffs_dev;
1583         ctx->ffs_data = ffs;
1584         return get_tree_nodev(fc, ffs_sb_fill);
1585 }
1586
1587 static void ffs_fs_free_fc(struct fs_context *fc)
1588 {
1589         struct ffs_sb_fill_data *ctx = fc->fs_private;
1590
1591         if (ctx) {
1592                 if (ctx->ffs_data) {
1593                         ffs_release_dev(ctx->ffs_data);
1594                         ffs_data_put(ctx->ffs_data);
1595                 }
1596
1597                 kfree(ctx);
1598         }
1599 }
1600
1601 static const struct fs_context_operations ffs_fs_context_ops = {
1602         .free           = ffs_fs_free_fc,
1603         .parse_param    = ffs_fs_parse_param,
1604         .get_tree       = ffs_fs_get_tree,
1605 };
1606
1607 static int ffs_fs_init_fs_context(struct fs_context *fc)
1608 {
1609         struct ffs_sb_fill_data *ctx;
1610
1611         ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1612         if (!ctx)
1613                 return -ENOMEM;
1614
1615         ctx->perms.mode = S_IFREG | 0600;
1616         ctx->perms.uid = GLOBAL_ROOT_UID;
1617         ctx->perms.gid = GLOBAL_ROOT_GID;
1618         ctx->root_mode = S_IFDIR | 0500;
1619         ctx->no_disconnect = false;
1620
1621         fc->fs_private = ctx;
1622         fc->ops = &ffs_fs_context_ops;
1623         return 0;
1624 }
1625
1626 static void
1627 ffs_fs_kill_sb(struct super_block *sb)
1628 {
1629         ENTER();
1630
1631         kill_litter_super(sb);
1632         if (sb->s_fs_info) {
1633                 ffs_release_dev(sb->s_fs_info);
1634                 ffs_data_closed(sb->s_fs_info);
1635         }
1636 }
1637
1638 static struct file_system_type ffs_fs_type = {
1639         .owner          = THIS_MODULE,
1640         .name           = "functionfs",
1641         .init_fs_context = ffs_fs_init_fs_context,
1642         .parameters     = ffs_fs_fs_parameters,
1643         .kill_sb        = ffs_fs_kill_sb,
1644 };
1645 MODULE_ALIAS_FS("functionfs");
1646
1647
1648 /* Driver's main init/cleanup functions *************************************/
1649
1650 static int functionfs_init(void)
1651 {
1652         int ret;
1653
1654         ENTER();
1655
1656         ret = register_filesystem(&ffs_fs_type);
1657         if (likely(!ret))
1658                 pr_info("file system registered\n");
1659         else
1660                 pr_err("failed registering file system (%d)\n", ret);
1661
1662         return ret;
1663 }
1664
1665 static void functionfs_cleanup(void)
1666 {
1667         ENTER();
1668
1669         pr_info("unloading\n");
1670         unregister_filesystem(&ffs_fs_type);
1671 }
1672
1673
1674 /* ffs_data and ffs_function construction and destruction code **************/
1675
1676 static void ffs_data_clear(struct ffs_data *ffs);
1677 static void ffs_data_reset(struct ffs_data *ffs);
1678
1679 static void ffs_data_get(struct ffs_data *ffs)
1680 {
1681         ENTER();
1682
1683         refcount_inc(&ffs->ref);
1684 }
1685
1686 static void ffs_data_opened(struct ffs_data *ffs)
1687 {
1688         ENTER();
1689
1690         refcount_inc(&ffs->ref);
1691         if (atomic_add_return(1, &ffs->opened) == 1 &&
1692                         ffs->state == FFS_DEACTIVATED) {
1693                 ffs->state = FFS_CLOSING;
1694                 ffs_data_reset(ffs);
1695         }
1696 }
1697
1698 static void ffs_data_put(struct ffs_data *ffs)
1699 {
1700         ENTER();
1701
1702         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1703                 pr_info("%s(): freeing\n", __func__);
1704                 ffs_data_clear(ffs);
1705                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1706                        waitqueue_active(&ffs->ep0req_completion.wait) ||
1707                        waitqueue_active(&ffs->wait));
1708                 destroy_workqueue(ffs->io_completion_wq);
1709                 kfree(ffs->dev_name);
1710                 kfree(ffs);
1711         }
1712 }
1713
1714 static void ffs_data_closed(struct ffs_data *ffs)
1715 {
1716         ENTER();
1717
1718         if (atomic_dec_and_test(&ffs->opened)) {
1719                 if (ffs->no_disconnect) {
1720                         ffs->state = FFS_DEACTIVATED;
1721                         if (ffs->epfiles) {
1722                                 ffs_epfiles_destroy(ffs->epfiles,
1723                                                    ffs->eps_count);
1724                                 ffs->epfiles = NULL;
1725                         }
1726                         if (ffs->setup_state == FFS_SETUP_PENDING)
1727                                 __ffs_ep0_stall(ffs);
1728                 } else {
1729                         ffs->state = FFS_CLOSING;
1730                         ffs_data_reset(ffs);
1731                 }
1732         }
1733         if (atomic_read(&ffs->opened) < 0) {
1734                 ffs->state = FFS_CLOSING;
1735                 ffs_data_reset(ffs);
1736         }
1737
1738         ffs_data_put(ffs);
1739 }
1740
1741 static struct ffs_data *ffs_data_new(const char *dev_name)
1742 {
1743         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1744         if (unlikely(!ffs))
1745                 return NULL;
1746
1747         ENTER();
1748
1749         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1750         if (!ffs->io_completion_wq) {
1751                 kfree(ffs);
1752                 return NULL;
1753         }
1754
1755         refcount_set(&ffs->ref, 1);
1756         atomic_set(&ffs->opened, 0);
1757         ffs->state = FFS_READ_DESCRIPTORS;
1758         mutex_init(&ffs->mutex);
1759         spin_lock_init(&ffs->eps_lock);
1760         init_waitqueue_head(&ffs->ev.waitq);
1761         init_waitqueue_head(&ffs->wait);
1762         init_completion(&ffs->ep0req_completion);
1763
1764         /* XXX REVISIT need to update it in some places, or do we? */
1765         ffs->ev.can_stall = 1;
1766
1767         return ffs;
1768 }
1769
1770 static void ffs_data_clear(struct ffs_data *ffs)
1771 {
1772         ENTER();
1773
1774         ffs_closed(ffs);
1775
1776         BUG_ON(ffs->gadget);
1777
1778         if (ffs->epfiles)
1779                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1780
1781         if (ffs->ffs_eventfd)
1782                 eventfd_ctx_put(ffs->ffs_eventfd);
1783
1784         kfree(ffs->raw_descs_data);
1785         kfree(ffs->raw_strings);
1786         kfree(ffs->stringtabs);
1787 }
1788
1789 static void ffs_data_reset(struct ffs_data *ffs)
1790 {
1791         ENTER();
1792
1793         ffs_data_clear(ffs);
1794
1795         ffs->epfiles = NULL;
1796         ffs->raw_descs_data = NULL;
1797         ffs->raw_descs = NULL;
1798         ffs->raw_strings = NULL;
1799         ffs->stringtabs = NULL;
1800
1801         ffs->raw_descs_length = 0;
1802         ffs->fs_descs_count = 0;
1803         ffs->hs_descs_count = 0;
1804         ffs->ss_descs_count = 0;
1805
1806         ffs->strings_count = 0;
1807         ffs->interfaces_count = 0;
1808         ffs->eps_count = 0;
1809
1810         ffs->ev.count = 0;
1811
1812         ffs->state = FFS_READ_DESCRIPTORS;
1813         ffs->setup_state = FFS_NO_SETUP;
1814         ffs->flags = 0;
1815 }
1816
1817
1818 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1819 {
1820         struct usb_gadget_strings **lang;
1821         int first_id;
1822
1823         ENTER();
1824
1825         if (WARN_ON(ffs->state != FFS_ACTIVE
1826                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1827                 return -EBADFD;
1828
1829         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1830         if (unlikely(first_id < 0))
1831                 return first_id;
1832
1833         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1834         if (unlikely(!ffs->ep0req))
1835                 return -ENOMEM;
1836         ffs->ep0req->complete = ffs_ep0_complete;
1837         ffs->ep0req->context = ffs;
1838
1839         lang = ffs->stringtabs;
1840         if (lang) {
1841                 for (; *lang; ++lang) {
1842                         struct usb_string *str = (*lang)->strings;
1843                         int id = first_id;
1844                         for (; str->s; ++id, ++str)
1845                                 str->id = id;
1846                 }
1847         }
1848
1849         ffs->gadget = cdev->gadget;
1850         ffs_data_get(ffs);
1851         return 0;
1852 }
1853
1854 static void functionfs_unbind(struct ffs_data *ffs)
1855 {
1856         ENTER();
1857
1858         if (!WARN_ON(!ffs->gadget)) {
1859                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1860                 ffs->ep0req = NULL;
1861                 ffs->gadget = NULL;
1862                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1863                 ffs_data_put(ffs);
1864         }
1865 }
1866
1867 static int ffs_epfiles_create(struct ffs_data *ffs)
1868 {
1869         struct ffs_epfile *epfile, *epfiles;
1870         unsigned i, count;
1871
1872         ENTER();
1873
1874         count = ffs->eps_count;
1875         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1876         if (!epfiles)
1877                 return -ENOMEM;
1878
1879         epfile = epfiles;
1880         for (i = 1; i <= count; ++i, ++epfile) {
1881                 epfile->ffs = ffs;
1882                 mutex_init(&epfile->mutex);
1883                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1884                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1885                 else
1886                         sprintf(epfile->name, "ep%u", i);
1887                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1888                                                  epfile,
1889                                                  &ffs_epfile_operations);
1890                 if (unlikely(!epfile->dentry)) {
1891                         ffs_epfiles_destroy(epfiles, i - 1);
1892                         return -ENOMEM;
1893                 }
1894         }
1895
1896         ffs->epfiles = epfiles;
1897         return 0;
1898 }
1899
1900 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1901 {
1902         struct ffs_epfile *epfile = epfiles;
1903
1904         ENTER();
1905
1906         for (; count; --count, ++epfile) {
1907                 BUG_ON(mutex_is_locked(&epfile->mutex));
1908                 if (epfile->dentry) {
1909                         d_delete(epfile->dentry);
1910                         dput(epfile->dentry);
1911                         epfile->dentry = NULL;
1912                 }
1913         }
1914
1915         kfree(epfiles);
1916 }
1917
1918 static void ffs_func_eps_disable(struct ffs_function *func)
1919 {
1920         struct ffs_ep *ep         = func->eps;
1921         struct ffs_epfile *epfile = func->ffs->epfiles;
1922         unsigned count            = func->ffs->eps_count;
1923         unsigned long flags;
1924
1925         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1926         while (count--) {
1927                 /* pending requests get nuked */
1928                 if (likely(ep->ep))
1929                         usb_ep_disable(ep->ep);
1930                 ++ep;
1931
1932                 if (epfile) {
1933                         epfile->ep = NULL;
1934                         __ffs_epfile_read_buffer_free(epfile);
1935                         ++epfile;
1936                 }
1937         }
1938         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1939 }
1940
1941 static int ffs_func_eps_enable(struct ffs_function *func)
1942 {
1943         struct ffs_data *ffs      = func->ffs;
1944         struct ffs_ep *ep         = func->eps;
1945         struct ffs_epfile *epfile = ffs->epfiles;
1946         unsigned count            = ffs->eps_count;
1947         unsigned long flags;
1948         int ret = 0;
1949
1950         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1951         while(count--) {
1952                 ep->ep->driver_data = ep;
1953
1954                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1955                 if (ret) {
1956                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1957                                         __func__, ep->ep->name, ret);
1958                         break;
1959                 }
1960
1961                 ret = usb_ep_enable(ep->ep);
1962                 if (likely(!ret)) {
1963                         epfile->ep = ep;
1964                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1965                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1966                 } else {
1967                         break;
1968                 }
1969
1970                 ++ep;
1971                 ++epfile;
1972         }
1973
1974         wake_up_interruptible(&ffs->wait);
1975         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1976
1977         return ret;
1978 }
1979
1980
1981 /* Parsing and building descriptors and strings *****************************/
1982
1983 /*
1984  * This validates if data pointed by data is a valid USB descriptor as
1985  * well as record how many interfaces, endpoints and strings are
1986  * required by given configuration.  Returns address after the
1987  * descriptor or NULL if data is invalid.
1988  */
1989
1990 enum ffs_entity_type {
1991         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1992 };
1993
1994 enum ffs_os_desc_type {
1995         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1996 };
1997
1998 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1999                                    u8 *valuep,
2000                                    struct usb_descriptor_header *desc,
2001                                    void *priv);
2002
2003 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2004                                     struct usb_os_desc_header *h, void *data,
2005                                     unsigned len, void *priv);
2006
2007 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2008                                            ffs_entity_callback entity,
2009                                            void *priv, int *current_class)
2010 {
2011         struct usb_descriptor_header *_ds = (void *)data;
2012         u8 length;
2013         int ret;
2014
2015         ENTER();
2016
2017         /* At least two bytes are required: length and type */
2018         if (len < 2) {
2019                 pr_vdebug("descriptor too short\n");
2020                 return -EINVAL;
2021         }
2022
2023         /* If we have at least as many bytes as the descriptor takes? */
2024         length = _ds->bLength;
2025         if (len < length) {
2026                 pr_vdebug("descriptor longer then available data\n");
2027                 return -EINVAL;
2028         }
2029
2030 #define __entity_check_INTERFACE(val)  1
2031 #define __entity_check_STRING(val)     (val)
2032 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2033 #define __entity(type, val) do {                                        \
2034                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2035                 if (unlikely(!__entity_check_ ##type(val))) {           \
2036                         pr_vdebug("invalid entity's value\n");          \
2037                         return -EINVAL;                                 \
2038                 }                                                       \
2039                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2040                 if (unlikely(ret < 0)) {                                \
2041                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2042                                  (val), ret);                           \
2043                         return ret;                                     \
2044                 }                                                       \
2045         } while (0)
2046
2047         /* Parse descriptor depending on type. */
2048         switch (_ds->bDescriptorType) {
2049         case USB_DT_DEVICE:
2050         case USB_DT_CONFIG:
2051         case USB_DT_STRING:
2052         case USB_DT_DEVICE_QUALIFIER:
2053                 /* function can't have any of those */
2054                 pr_vdebug("descriptor reserved for gadget: %d\n",
2055                       _ds->bDescriptorType);
2056                 return -EINVAL;
2057
2058         case USB_DT_INTERFACE: {
2059                 struct usb_interface_descriptor *ds = (void *)_ds;
2060                 pr_vdebug("interface descriptor\n");
2061                 if (length != sizeof *ds)
2062                         goto inv_length;
2063
2064                 __entity(INTERFACE, ds->bInterfaceNumber);
2065                 if (ds->iInterface)
2066                         __entity(STRING, ds->iInterface);
2067                 *current_class = ds->bInterfaceClass;
2068         }
2069                 break;
2070
2071         case USB_DT_ENDPOINT: {
2072                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2073                 pr_vdebug("endpoint descriptor\n");
2074                 if (length != USB_DT_ENDPOINT_SIZE &&
2075                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2076                         goto inv_length;
2077                 __entity(ENDPOINT, ds->bEndpointAddress);
2078         }
2079                 break;
2080
2081         case USB_TYPE_CLASS | 0x01:
2082                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2083                         pr_vdebug("hid descriptor\n");
2084                         if (length != sizeof(struct hid_descriptor))
2085                                 goto inv_length;
2086                         break;
2087                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2088                         pr_vdebug("ccid descriptor\n");
2089                         if (length != sizeof(struct ccid_descriptor))
2090                                 goto inv_length;
2091                         break;
2092                 } else {
2093                         pr_vdebug("unknown descriptor: %d for class %d\n",
2094                               _ds->bDescriptorType, *current_class);
2095                         return -EINVAL;
2096                 }
2097
2098         case USB_DT_OTG:
2099                 if (length != sizeof(struct usb_otg_descriptor))
2100                         goto inv_length;
2101                 break;
2102
2103         case USB_DT_INTERFACE_ASSOCIATION: {
2104                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2105                 pr_vdebug("interface association descriptor\n");
2106                 if (length != sizeof *ds)
2107                         goto inv_length;
2108                 if (ds->iFunction)
2109                         __entity(STRING, ds->iFunction);
2110         }
2111                 break;
2112
2113         case USB_DT_SS_ENDPOINT_COMP:
2114                 pr_vdebug("EP SS companion descriptor\n");
2115                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2116                         goto inv_length;
2117                 break;
2118
2119         case USB_DT_OTHER_SPEED_CONFIG:
2120         case USB_DT_INTERFACE_POWER:
2121         case USB_DT_DEBUG:
2122         case USB_DT_SECURITY:
2123         case USB_DT_CS_RADIO_CONTROL:
2124                 /* TODO */
2125                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2126                 return -EINVAL;
2127
2128         default:
2129                 /* We should never be here */
2130                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2131                 return -EINVAL;
2132
2133 inv_length:
2134                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2135                           _ds->bLength, _ds->bDescriptorType);
2136                 return -EINVAL;
2137         }
2138
2139 #undef __entity
2140 #undef __entity_check_DESCRIPTOR
2141 #undef __entity_check_INTERFACE
2142 #undef __entity_check_STRING
2143 #undef __entity_check_ENDPOINT
2144
2145         return length;
2146 }
2147
2148 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2149                                      ffs_entity_callback entity, void *priv)
2150 {
2151         const unsigned _len = len;
2152         unsigned long num = 0;
2153         int current_class = -1;
2154
2155         ENTER();
2156
2157         for (;;) {
2158                 int ret;
2159
2160                 if (num == count)
2161                         data = NULL;
2162
2163                 /* Record "descriptor" entity */
2164                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2165                 if (unlikely(ret < 0)) {
2166                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2167                                  num, ret);
2168                         return ret;
2169                 }
2170
2171                 if (!data)
2172                         return _len - len;
2173
2174                 ret = ffs_do_single_desc(data, len, entity, priv,
2175                         &current_class);
2176                 if (unlikely(ret < 0)) {
2177                         pr_debug("%s returns %d\n", __func__, ret);
2178                         return ret;
2179                 }
2180
2181                 len -= ret;
2182                 data += ret;
2183                 ++num;
2184         }
2185 }
2186
2187 static int __ffs_data_do_entity(enum ffs_entity_type type,
2188                                 u8 *valuep, struct usb_descriptor_header *desc,
2189                                 void *priv)
2190 {
2191         struct ffs_desc_helper *helper = priv;
2192         struct usb_endpoint_descriptor *d;
2193
2194         ENTER();
2195
2196         switch (type) {
2197         case FFS_DESCRIPTOR:
2198                 break;
2199
2200         case FFS_INTERFACE:
2201                 /*
2202                  * Interfaces are indexed from zero so if we
2203                  * encountered interface "n" then there are at least
2204                  * "n+1" interfaces.
2205                  */
2206                 if (*valuep >= helper->interfaces_count)
2207                         helper->interfaces_count = *valuep + 1;
2208                 break;
2209
2210         case FFS_STRING:
2211                 /*
2212                  * Strings are indexed from 1 (0 is reserved
2213                  * for languages list)
2214                  */
2215                 if (*valuep > helper->ffs->strings_count)
2216                         helper->ffs->strings_count = *valuep;
2217                 break;
2218
2219         case FFS_ENDPOINT:
2220                 d = (void *)desc;
2221                 helper->eps_count++;
2222                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2223                         return -EINVAL;
2224                 /* Check if descriptors for any speed were already parsed */
2225                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2226                         helper->ffs->eps_addrmap[helper->eps_count] =
2227                                 d->bEndpointAddress;
2228                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2229                                 d->bEndpointAddress)
2230                         return -EINVAL;
2231                 break;
2232         }
2233
2234         return 0;
2235 }
2236
2237 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2238                                    struct usb_os_desc_header *desc)
2239 {
2240         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2241         u16 w_index = le16_to_cpu(desc->wIndex);
2242
2243         if (bcd_version != 1) {
2244                 pr_vdebug("unsupported os descriptors version: %d",
2245                           bcd_version);
2246                 return -EINVAL;
2247         }
2248         switch (w_index) {
2249         case 0x4:
2250                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2251                 break;
2252         case 0x5:
2253                 *next_type = FFS_OS_DESC_EXT_PROP;
2254                 break;
2255         default:
2256                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2257                 return -EINVAL;
2258         }
2259
2260         return sizeof(*desc);
2261 }
2262
2263 /*
2264  * Process all extended compatibility/extended property descriptors
2265  * of a feature descriptor
2266  */
2267 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2268                                               enum ffs_os_desc_type type,
2269                                               u16 feature_count,
2270                                               ffs_os_desc_callback entity,
2271                                               void *priv,
2272                                               struct usb_os_desc_header *h)
2273 {
2274         int ret;
2275         const unsigned _len = len;
2276
2277         ENTER();
2278
2279         /* loop over all ext compat/ext prop descriptors */
2280         while (feature_count--) {
2281                 ret = entity(type, h, data, len, priv);
2282                 if (unlikely(ret < 0)) {
2283                         pr_debug("bad OS descriptor, type: %d\n", type);
2284                         return ret;
2285                 }
2286                 data += ret;
2287                 len -= ret;
2288         }
2289         return _len - len;
2290 }
2291
2292 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2293 static int __must_check ffs_do_os_descs(unsigned count,
2294                                         char *data, unsigned len,
2295                                         ffs_os_desc_callback entity, void *priv)
2296 {
2297         const unsigned _len = len;
2298         unsigned long num = 0;
2299
2300         ENTER();
2301
2302         for (num = 0; num < count; ++num) {
2303                 int ret;
2304                 enum ffs_os_desc_type type;
2305                 u16 feature_count;
2306                 struct usb_os_desc_header *desc = (void *)data;
2307
2308                 if (len < sizeof(*desc))
2309                         return -EINVAL;
2310
2311                 /*
2312                  * Record "descriptor" entity.
2313                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2314                  * Move the data pointer to the beginning of extended
2315                  * compatibilities proper or extended properties proper
2316                  * portions of the data
2317                  */
2318                 if (le32_to_cpu(desc->dwLength) > len)
2319                         return -EINVAL;
2320
2321                 ret = __ffs_do_os_desc_header(&type, desc);
2322                 if (unlikely(ret < 0)) {
2323                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2324                                  num, ret);
2325                         return ret;
2326                 }
2327                 /*
2328                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2329                  */
2330                 feature_count = le16_to_cpu(desc->wCount);
2331                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2332                     (feature_count > 255 || desc->Reserved))
2333                                 return -EINVAL;
2334                 len -= ret;
2335                 data += ret;
2336
2337                 /*
2338                  * Process all function/property descriptors
2339                  * of this Feature Descriptor
2340                  */
2341                 ret = ffs_do_single_os_desc(data, len, type,
2342                                             feature_count, entity, priv, desc);
2343                 if (unlikely(ret < 0)) {
2344                         pr_debug("%s returns %d\n", __func__, ret);
2345                         return ret;
2346                 }
2347
2348                 len -= ret;
2349                 data += ret;
2350         }
2351         return _len - len;
2352 }
2353
2354 /**
2355  * Validate contents of the buffer from userspace related to OS descriptors.
2356  */
2357 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2358                                  struct usb_os_desc_header *h, void *data,
2359                                  unsigned len, void *priv)
2360 {
2361         struct ffs_data *ffs = priv;
2362         u8 length;
2363
2364         ENTER();
2365
2366         switch (type) {
2367         case FFS_OS_DESC_EXT_COMPAT: {
2368                 struct usb_ext_compat_desc *d = data;
2369                 int i;
2370
2371                 if (len < sizeof(*d) ||
2372                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2373                         return -EINVAL;
2374                 if (d->Reserved1 != 1) {
2375                         /*
2376                          * According to the spec, Reserved1 must be set to 1
2377                          * but older kernels incorrectly rejected non-zero
2378                          * values.  We fix it here to avoid returning EINVAL
2379                          * in response to values we used to accept.
2380                          */
2381                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2382                         d->Reserved1 = 1;
2383                 }
2384                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2385                         if (d->Reserved2[i])
2386                                 return -EINVAL;
2387
2388                 length = sizeof(struct usb_ext_compat_desc);
2389         }
2390                 break;
2391         case FFS_OS_DESC_EXT_PROP: {
2392                 struct usb_ext_prop_desc *d = data;
2393                 u32 type, pdl;
2394                 u16 pnl;
2395
2396                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2397                         return -EINVAL;
2398                 length = le32_to_cpu(d->dwSize);
2399                 if (len < length)
2400                         return -EINVAL;
2401                 type = le32_to_cpu(d->dwPropertyDataType);
2402                 if (type < USB_EXT_PROP_UNICODE ||
2403                     type > USB_EXT_PROP_UNICODE_MULTI) {
2404                         pr_vdebug("unsupported os descriptor property type: %d",
2405                                   type);
2406                         return -EINVAL;
2407                 }
2408                 pnl = le16_to_cpu(d->wPropertyNameLength);
2409                 if (length < 14 + pnl) {
2410                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2411                                   length, pnl, type);
2412                         return -EINVAL;
2413                 }
2414                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2415                 if (length != 14 + pnl + pdl) {
2416                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2417                                   length, pnl, pdl, type);
2418                         return -EINVAL;
2419                 }
2420                 ++ffs->ms_os_descs_ext_prop_count;
2421                 /* property name reported to the host as "WCHAR"s */
2422                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2423                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2424         }
2425                 break;
2426         default:
2427                 pr_vdebug("unknown descriptor: %d\n", type);
2428                 return -EINVAL;
2429         }
2430         return length;
2431 }
2432
2433 static int __ffs_data_got_descs(struct ffs_data *ffs,
2434                                 char *const _data, size_t len)
2435 {
2436         char *data = _data, *raw_descs;
2437         unsigned os_descs_count = 0, counts[3], flags;
2438         int ret = -EINVAL, i;
2439         struct ffs_desc_helper helper;
2440
2441         ENTER();
2442
2443         if (get_unaligned_le32(data + 4) != len)
2444                 goto error;
2445
2446         switch (get_unaligned_le32(data)) {
2447         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2448                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2449                 data += 8;
2450                 len  -= 8;
2451                 break;
2452         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2453                 flags = get_unaligned_le32(data + 8);
2454                 ffs->user_flags = flags;
2455                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2456                               FUNCTIONFS_HAS_HS_DESC |
2457                               FUNCTIONFS_HAS_SS_DESC |
2458                               FUNCTIONFS_HAS_MS_OS_DESC |
2459                               FUNCTIONFS_VIRTUAL_ADDR |
2460                               FUNCTIONFS_EVENTFD |
2461                               FUNCTIONFS_ALL_CTRL_RECIP |
2462                               FUNCTIONFS_CONFIG0_SETUP)) {
2463                         ret = -ENOSYS;
2464                         goto error;
2465                 }
2466                 data += 12;
2467                 len  -= 12;
2468                 break;
2469         default:
2470                 goto error;
2471         }
2472
2473         if (flags & FUNCTIONFS_EVENTFD) {
2474                 if (len < 4)
2475                         goto error;
2476                 ffs->ffs_eventfd =
2477                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2478                 if (IS_ERR(ffs->ffs_eventfd)) {
2479                         ret = PTR_ERR(ffs->ffs_eventfd);
2480                         ffs->ffs_eventfd = NULL;
2481                         goto error;
2482                 }
2483                 data += 4;
2484                 len  -= 4;
2485         }
2486
2487         /* Read fs_count, hs_count and ss_count (if present) */
2488         for (i = 0; i < 3; ++i) {
2489                 if (!(flags & (1 << i))) {
2490                         counts[i] = 0;
2491                 } else if (len < 4) {
2492                         goto error;
2493                 } else {
2494                         counts[i] = get_unaligned_le32(data);
2495                         data += 4;
2496                         len  -= 4;
2497                 }
2498         }
2499         if (flags & (1 << i)) {
2500                 if (len < 4) {
2501                         goto error;
2502                 }
2503                 os_descs_count = get_unaligned_le32(data);
2504                 data += 4;
2505                 len -= 4;
2506         };
2507
2508         /* Read descriptors */
2509         raw_descs = data;
2510         helper.ffs = ffs;
2511         for (i = 0; i < 3; ++i) {
2512                 if (!counts[i])
2513                         continue;
2514                 helper.interfaces_count = 0;
2515                 helper.eps_count = 0;
2516                 ret = ffs_do_descs(counts[i], data, len,
2517                                    __ffs_data_do_entity, &helper);
2518                 if (ret < 0)
2519                         goto error;
2520                 if (!ffs->eps_count && !ffs->interfaces_count) {
2521                         ffs->eps_count = helper.eps_count;
2522                         ffs->interfaces_count = helper.interfaces_count;
2523                 } else {
2524                         if (ffs->eps_count != helper.eps_count) {
2525                                 ret = -EINVAL;
2526                                 goto error;
2527                         }
2528                         if (ffs->interfaces_count != helper.interfaces_count) {
2529                                 ret = -EINVAL;
2530                                 goto error;
2531                         }
2532                 }
2533                 data += ret;
2534                 len  -= ret;
2535         }
2536         if (os_descs_count) {
2537                 ret = ffs_do_os_descs(os_descs_count, data, len,
2538                                       __ffs_data_do_os_desc, ffs);
2539                 if (ret < 0)
2540                         goto error;
2541                 data += ret;
2542                 len -= ret;
2543         }
2544
2545         if (raw_descs == data || len) {
2546                 ret = -EINVAL;
2547                 goto error;
2548         }
2549
2550         ffs->raw_descs_data     = _data;
2551         ffs->raw_descs          = raw_descs;
2552         ffs->raw_descs_length   = data - raw_descs;
2553         ffs->fs_descs_count     = counts[0];
2554         ffs->hs_descs_count     = counts[1];
2555         ffs->ss_descs_count     = counts[2];
2556         ffs->ms_os_descs_count  = os_descs_count;
2557
2558         return 0;
2559
2560 error:
2561         kfree(_data);
2562         return ret;
2563 }
2564
2565 static int __ffs_data_got_strings(struct ffs_data *ffs,
2566                                   char *const _data, size_t len)
2567 {
2568         u32 str_count, needed_count, lang_count;
2569         struct usb_gadget_strings **stringtabs, *t;
2570         const char *data = _data;
2571         struct usb_string *s;
2572
2573         ENTER();
2574
2575         if (unlikely(len < 16 ||
2576                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2577                      get_unaligned_le32(data + 4) != len))
2578                 goto error;
2579         str_count  = get_unaligned_le32(data + 8);
2580         lang_count = get_unaligned_le32(data + 12);
2581
2582         /* if one is zero the other must be zero */
2583         if (unlikely(!str_count != !lang_count))
2584                 goto error;
2585
2586         /* Do we have at least as many strings as descriptors need? */
2587         needed_count = ffs->strings_count;
2588         if (unlikely(str_count < needed_count))
2589                 goto error;
2590
2591         /*
2592          * If we don't need any strings just return and free all
2593          * memory.
2594          */
2595         if (!needed_count) {
2596                 kfree(_data);
2597                 return 0;
2598         }
2599
2600         /* Allocate everything in one chunk so there's less maintenance. */
2601         {
2602                 unsigned i = 0;
2603                 vla_group(d);
2604                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2605                         lang_count + 1);
2606                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2607                 vla_item(d, struct usb_string, strings,
2608                         lang_count*(needed_count+1));
2609
2610                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2611
2612                 if (unlikely(!vlabuf)) {
2613                         kfree(_data);
2614                         return -ENOMEM;
2615                 }
2616
2617                 /* Initialize the VLA pointers */
2618                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2619                 t = vla_ptr(vlabuf, d, stringtab);
2620                 i = lang_count;
2621                 do {
2622                         *stringtabs++ = t++;
2623                 } while (--i);
2624                 *stringtabs = NULL;
2625
2626                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2627                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2628                 t = vla_ptr(vlabuf, d, stringtab);
2629                 s = vla_ptr(vlabuf, d, strings);
2630         }
2631
2632         /* For each language */
2633         data += 16;
2634         len -= 16;
2635
2636         do { /* lang_count > 0 so we can use do-while */
2637                 unsigned needed = needed_count;
2638
2639                 if (unlikely(len < 3))
2640                         goto error_free;
2641                 t->language = get_unaligned_le16(data);
2642                 t->strings  = s;
2643                 ++t;
2644
2645                 data += 2;
2646                 len -= 2;
2647
2648                 /* For each string */
2649                 do { /* str_count > 0 so we can use do-while */
2650                         size_t length = strnlen(data, len);
2651
2652                         if (unlikely(length == len))
2653                                 goto error_free;
2654
2655                         /*
2656                          * User may provide more strings then we need,
2657                          * if that's the case we simply ignore the
2658                          * rest
2659                          */
2660                         if (likely(needed)) {
2661                                 /*
2662                                  * s->id will be set while adding
2663                                  * function to configuration so for
2664                                  * now just leave garbage here.
2665                                  */
2666                                 s->s = data;
2667                                 --needed;
2668                                 ++s;
2669                         }
2670
2671                         data += length + 1;
2672                         len -= length + 1;
2673                 } while (--str_count);
2674
2675                 s->id = 0;   /* terminator */
2676                 s->s = NULL;
2677                 ++s;
2678
2679         } while (--lang_count);
2680
2681         /* Some garbage left? */
2682         if (unlikely(len))
2683                 goto error_free;
2684
2685         /* Done! */
2686         ffs->stringtabs = stringtabs;
2687         ffs->raw_strings = _data;
2688
2689         return 0;
2690
2691 error_free:
2692         kfree(stringtabs);
2693 error:
2694         kfree(_data);
2695         return -EINVAL;
2696 }
2697
2698
2699 /* Events handling and management *******************************************/
2700
2701 static void __ffs_event_add(struct ffs_data *ffs,
2702                             enum usb_functionfs_event_type type)
2703 {
2704         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2705         int neg = 0;
2706
2707         /*
2708          * Abort any unhandled setup
2709          *
2710          * We do not need to worry about some cmpxchg() changing value
2711          * of ffs->setup_state without holding the lock because when
2712          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2713          * the source does nothing.
2714          */
2715         if (ffs->setup_state == FFS_SETUP_PENDING)
2716                 ffs->setup_state = FFS_SETUP_CANCELLED;
2717
2718         /*
2719          * Logic of this function guarantees that there are at most four pending
2720          * evens on ffs->ev.types queue.  This is important because the queue
2721          * has space for four elements only and __ffs_ep0_read_events function
2722          * depends on that limit as well.  If more event types are added, those
2723          * limits have to be revisited or guaranteed to still hold.
2724          */
2725         switch (type) {
2726         case FUNCTIONFS_RESUME:
2727                 rem_type2 = FUNCTIONFS_SUSPEND;
2728                 /* FALL THROUGH */
2729         case FUNCTIONFS_SUSPEND:
2730         case FUNCTIONFS_SETUP:
2731                 rem_type1 = type;
2732                 /* Discard all similar events */
2733                 break;
2734
2735         case FUNCTIONFS_BIND:
2736         case FUNCTIONFS_UNBIND:
2737         case FUNCTIONFS_DISABLE:
2738         case FUNCTIONFS_ENABLE:
2739                 /* Discard everything other then power management. */
2740                 rem_type1 = FUNCTIONFS_SUSPEND;
2741                 rem_type2 = FUNCTIONFS_RESUME;
2742                 neg = 1;
2743                 break;
2744
2745         default:
2746                 WARN(1, "%d: unknown event, this should not happen\n", type);
2747                 return;
2748         }
2749
2750         {
2751                 u8 *ev  = ffs->ev.types, *out = ev;
2752                 unsigned n = ffs->ev.count;
2753                 for (; n; --n, ++ev)
2754                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2755                                 *out++ = *ev;
2756                         else
2757                                 pr_vdebug("purging event %d\n", *ev);
2758                 ffs->ev.count = out - ffs->ev.types;
2759         }
2760
2761         pr_vdebug("adding event %d\n", type);
2762         ffs->ev.types[ffs->ev.count++] = type;
2763         wake_up_locked(&ffs->ev.waitq);
2764         if (ffs->ffs_eventfd)
2765                 eventfd_signal(ffs->ffs_eventfd, 1);
2766 }
2767
2768 static void ffs_event_add(struct ffs_data *ffs,
2769                           enum usb_functionfs_event_type type)
2770 {
2771         unsigned long flags;
2772         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2773         __ffs_event_add(ffs, type);
2774         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2775 }
2776
2777 /* Bind/unbind USB function hooks *******************************************/
2778
2779 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2780 {
2781         int i;
2782
2783         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2784                 if (ffs->eps_addrmap[i] == endpoint_address)
2785                         return i;
2786         return -ENOENT;
2787 }
2788
2789 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2790                                     struct usb_descriptor_header *desc,
2791                                     void *priv)
2792 {
2793         struct usb_endpoint_descriptor *ds = (void *)desc;
2794         struct ffs_function *func = priv;
2795         struct ffs_ep *ffs_ep;
2796         unsigned ep_desc_id;
2797         int idx;
2798         static const char *speed_names[] = { "full", "high", "super" };
2799
2800         if (type != FFS_DESCRIPTOR)
2801                 return 0;
2802
2803         /*
2804          * If ss_descriptors is not NULL, we are reading super speed
2805          * descriptors; if hs_descriptors is not NULL, we are reading high
2806          * speed descriptors; otherwise, we are reading full speed
2807          * descriptors.
2808          */
2809         if (func->function.ss_descriptors) {
2810                 ep_desc_id = 2;
2811                 func->function.ss_descriptors[(long)valuep] = desc;
2812         } else if (func->function.hs_descriptors) {
2813                 ep_desc_id = 1;
2814                 func->function.hs_descriptors[(long)valuep] = desc;
2815         } else {
2816                 ep_desc_id = 0;
2817                 func->function.fs_descriptors[(long)valuep]    = desc;
2818         }
2819
2820         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2821                 return 0;
2822
2823         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2824         if (idx < 0)
2825                 return idx;
2826
2827         ffs_ep = func->eps + idx;
2828
2829         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2830                 pr_err("two %sspeed descriptors for EP %d\n",
2831                           speed_names[ep_desc_id],
2832                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2833                 return -EINVAL;
2834         }
2835         ffs_ep->descs[ep_desc_id] = ds;
2836
2837         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2838         if (ffs_ep->ep) {
2839                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2840                 if (!ds->wMaxPacketSize)
2841                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2842         } else {
2843                 struct usb_request *req;
2844                 struct usb_ep *ep;
2845                 u8 bEndpointAddress;
2846                 u16 wMaxPacketSize;
2847
2848                 /*
2849                  * We back up bEndpointAddress because autoconfig overwrites
2850                  * it with physical endpoint address.
2851                  */
2852                 bEndpointAddress = ds->bEndpointAddress;
2853                 /*
2854                  * We back up wMaxPacketSize because autoconfig treats
2855                  * endpoint descriptors as if they were full speed.
2856                  */
2857                 wMaxPacketSize = ds->wMaxPacketSize;
2858                 pr_vdebug("autoconfig\n");
2859                 ep = usb_ep_autoconfig(func->gadget, ds);
2860                 if (unlikely(!ep))
2861                         return -ENOTSUPP;
2862                 ep->driver_data = func->eps + idx;
2863
2864                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2865                 if (unlikely(!req))
2866                         return -ENOMEM;
2867
2868                 ffs_ep->ep  = ep;
2869                 ffs_ep->req = req;
2870                 func->eps_revmap[ds->bEndpointAddress &
2871                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2872                 /*
2873                  * If we use virtual address mapping, we restore
2874                  * original bEndpointAddress value.
2875                  */
2876                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2877                         ds->bEndpointAddress = bEndpointAddress;
2878                 /*
2879                  * Restore wMaxPacketSize which was potentially
2880                  * overwritten by autoconfig.
2881                  */
2882                 ds->wMaxPacketSize = wMaxPacketSize;
2883         }
2884         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2885
2886         return 0;
2887 }
2888
2889 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2890                                    struct usb_descriptor_header *desc,
2891                                    void *priv)
2892 {
2893         struct ffs_function *func = priv;
2894         unsigned idx;
2895         u8 newValue;
2896
2897         switch (type) {
2898         default:
2899         case FFS_DESCRIPTOR:
2900                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2901                 return 0;
2902
2903         case FFS_INTERFACE:
2904                 idx = *valuep;
2905                 if (func->interfaces_nums[idx] < 0) {
2906                         int id = usb_interface_id(func->conf, &func->function);
2907                         if (unlikely(id < 0))
2908                                 return id;
2909                         func->interfaces_nums[idx] = id;
2910                 }
2911                 newValue = func->interfaces_nums[idx];
2912                 break;
2913
2914         case FFS_STRING:
2915                 /* String' IDs are allocated when fsf_data is bound to cdev */
2916                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2917                 break;
2918
2919         case FFS_ENDPOINT:
2920                 /*
2921                  * USB_DT_ENDPOINT are handled in
2922                  * __ffs_func_bind_do_descs().
2923                  */
2924                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2925                         return 0;
2926
2927                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2928                 if (unlikely(!func->eps[idx].ep))
2929                         return -EINVAL;
2930
2931                 {
2932                         struct usb_endpoint_descriptor **descs;
2933                         descs = func->eps[idx].descs;
2934                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2935                 }
2936                 break;
2937         }
2938
2939         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2940         *valuep = newValue;
2941         return 0;
2942 }
2943
2944 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2945                                       struct usb_os_desc_header *h, void *data,
2946                                       unsigned len, void *priv)
2947 {
2948         struct ffs_function *func = priv;
2949         u8 length = 0;
2950
2951         switch (type) {
2952         case FFS_OS_DESC_EXT_COMPAT: {
2953                 struct usb_ext_compat_desc *desc = data;
2954                 struct usb_os_desc_table *t;
2955
2956                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2957                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2958                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2959                        ARRAY_SIZE(desc->CompatibleID) +
2960                        ARRAY_SIZE(desc->SubCompatibleID));
2961                 length = sizeof(*desc);
2962         }
2963                 break;
2964         case FFS_OS_DESC_EXT_PROP: {
2965                 struct usb_ext_prop_desc *desc = data;
2966                 struct usb_os_desc_table *t;
2967                 struct usb_os_desc_ext_prop *ext_prop;
2968                 char *ext_prop_name;
2969                 char *ext_prop_data;
2970
2971                 t = &func->function.os_desc_table[h->interface];
2972                 t->if_id = func->interfaces_nums[h->interface];
2973
2974                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2975                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2976
2977                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2978                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2979                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2980                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2981                 length = ext_prop->name_len + ext_prop->data_len + 14;
2982
2983                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2984                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2985                         ext_prop->name_len;
2986
2987                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2988                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2989                         ext_prop->data_len;
2990                 memcpy(ext_prop_data,
2991                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2992                        ext_prop->data_len);
2993                 /* unicode data reported to the host as "WCHAR"s */
2994                 switch (ext_prop->type) {
2995                 case USB_EXT_PROP_UNICODE:
2996                 case USB_EXT_PROP_UNICODE_ENV:
2997                 case USB_EXT_PROP_UNICODE_LINK:
2998                 case USB_EXT_PROP_UNICODE_MULTI:
2999                         ext_prop->data_len *= 2;
3000                         break;
3001                 }
3002                 ext_prop->data = ext_prop_data;
3003
3004                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3005                        ext_prop->name_len);
3006                 /* property name reported to the host as "WCHAR"s */
3007                 ext_prop->name_len *= 2;
3008                 ext_prop->name = ext_prop_name;
3009
3010                 t->os_desc->ext_prop_len +=
3011                         ext_prop->name_len + ext_prop->data_len + 14;
3012                 ++t->os_desc->ext_prop_count;
3013                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3014         }
3015                 break;
3016         default:
3017                 pr_vdebug("unknown descriptor: %d\n", type);
3018         }
3019
3020         return length;
3021 }
3022
3023 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3024                                                 struct usb_configuration *c)
3025 {
3026         struct ffs_function *func = ffs_func_from_usb(f);
3027         struct f_fs_opts *ffs_opts =
3028                 container_of(f->fi, struct f_fs_opts, func_inst);
3029         int ret;
3030
3031         ENTER();
3032
3033         /*
3034          * Legacy gadget triggers binding in functionfs_ready_callback,
3035          * which already uses locking; taking the same lock here would
3036          * cause a deadlock.
3037          *
3038          * Configfs-enabled gadgets however do need ffs_dev_lock.
3039          */
3040         if (!ffs_opts->no_configfs)
3041                 ffs_dev_lock();
3042         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3043         func->ffs = ffs_opts->dev->ffs_data;
3044         if (!ffs_opts->no_configfs)
3045                 ffs_dev_unlock();
3046         if (ret)
3047                 return ERR_PTR(ret);
3048
3049         func->conf = c;
3050         func->gadget = c->cdev->gadget;
3051
3052         /*
3053          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3054          * configurations are bound in sequence with list_for_each_entry,
3055          * in each configuration its functions are bound in sequence
3056          * with list_for_each_entry, so we assume no race condition
3057          * with regard to ffs_opts->bound access
3058          */
3059         if (!ffs_opts->refcnt) {
3060                 ret = functionfs_bind(func->ffs, c->cdev);
3061                 if (ret)
3062                         return ERR_PTR(ret);
3063         }
3064         ffs_opts->refcnt++;
3065         func->function.strings = func->ffs->stringtabs;
3066
3067         return ffs_opts;
3068 }
3069
3070 static int _ffs_func_bind(struct usb_configuration *c,
3071                           struct usb_function *f)
3072 {
3073         struct ffs_function *func = ffs_func_from_usb(f);
3074         struct ffs_data *ffs = func->ffs;
3075
3076         const int full = !!func->ffs->fs_descs_count;
3077         const int high = !!func->ffs->hs_descs_count;
3078         const int super = !!func->ffs->ss_descs_count;
3079
3080         int fs_len, hs_len, ss_len, ret, i;
3081         struct ffs_ep *eps_ptr;
3082
3083         /* Make it a single chunk, less management later on */
3084         vla_group(d);
3085         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3086         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3087                 full ? ffs->fs_descs_count + 1 : 0);
3088         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3089                 high ? ffs->hs_descs_count + 1 : 0);
3090         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3091                 super ? ffs->ss_descs_count + 1 : 0);
3092         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3093         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3094                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3095         vla_item_with_sz(d, char[16], ext_compat,
3096                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3097         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3098                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3099         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3100                          ffs->ms_os_descs_ext_prop_count);
3101         vla_item_with_sz(d, char, ext_prop_name,
3102                          ffs->ms_os_descs_ext_prop_name_len);
3103         vla_item_with_sz(d, char, ext_prop_data,
3104                          ffs->ms_os_descs_ext_prop_data_len);
3105         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3106         char *vlabuf;
3107
3108         ENTER();
3109
3110         /* Has descriptors only for speeds gadget does not support */
3111         if (unlikely(!(full | high | super)))
3112                 return -ENOTSUPP;
3113
3114         /* Allocate a single chunk, less management later on */
3115         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3116         if (unlikely(!vlabuf))
3117                 return -ENOMEM;
3118
3119         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3120         ffs->ms_os_descs_ext_prop_name_avail =
3121                 vla_ptr(vlabuf, d, ext_prop_name);
3122         ffs->ms_os_descs_ext_prop_data_avail =
3123                 vla_ptr(vlabuf, d, ext_prop_data);
3124
3125         /* Copy descriptors  */
3126         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3127                ffs->raw_descs_length);
3128
3129         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3130         eps_ptr = vla_ptr(vlabuf, d, eps);
3131         for (i = 0; i < ffs->eps_count; i++)
3132                 eps_ptr[i].num = -1;
3133
3134         /* Save pointers
3135          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3136         */
3137         func->eps             = vla_ptr(vlabuf, d, eps);
3138         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3139
3140         /*
3141          * Go through all the endpoint descriptors and allocate
3142          * endpoints first, so that later we can rewrite the endpoint
3143          * numbers without worrying that it may be described later on.
3144          */
3145         if (likely(full)) {
3146                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3147                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3148                                       vla_ptr(vlabuf, d, raw_descs),
3149                                       d_raw_descs__sz,
3150                                       __ffs_func_bind_do_descs, func);
3151                 if (unlikely(fs_len < 0)) {
3152                         ret = fs_len;
3153                         goto error;
3154                 }
3155         } else {
3156                 fs_len = 0;
3157         }
3158
3159         if (likely(high)) {
3160                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3161                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3162                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3163                                       d_raw_descs__sz - fs_len,
3164                                       __ffs_func_bind_do_descs, func);
3165                 if (unlikely(hs_len < 0)) {
3166                         ret = hs_len;
3167                         goto error;
3168                 }
3169         } else {
3170                 hs_len = 0;
3171         }
3172
3173         if (likely(super)) {
3174                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3175                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3176                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3177                                 d_raw_descs__sz - fs_len - hs_len,
3178                                 __ffs_func_bind_do_descs, func);
3179                 if (unlikely(ss_len < 0)) {
3180                         ret = ss_len;
3181                         goto error;
3182                 }
3183         } else {
3184                 ss_len = 0;
3185         }
3186
3187         /*
3188          * Now handle interface numbers allocation and interface and
3189          * endpoint numbers rewriting.  We can do that in one go
3190          * now.
3191          */
3192         ret = ffs_do_descs(ffs->fs_descs_count +
3193                            (high ? ffs->hs_descs_count : 0) +
3194                            (super ? ffs->ss_descs_count : 0),
3195                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3196                            __ffs_func_bind_do_nums, func);
3197         if (unlikely(ret < 0))
3198                 goto error;
3199
3200         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3201         if (c->cdev->use_os_string) {
3202                 for (i = 0; i < ffs->interfaces_count; ++i) {
3203                         struct usb_os_desc *desc;
3204
3205                         desc = func->function.os_desc_table[i].os_desc =
3206                                 vla_ptr(vlabuf, d, os_desc) +
3207                                 i * sizeof(struct usb_os_desc);
3208                         desc->ext_compat_id =
3209                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3210                         INIT_LIST_HEAD(&desc->ext_prop);
3211                 }
3212                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3213                                       vla_ptr(vlabuf, d, raw_descs) +
3214                                       fs_len + hs_len + ss_len,
3215                                       d_raw_descs__sz - fs_len - hs_len -
3216                                       ss_len,
3217                                       __ffs_func_bind_do_os_desc, func);
3218                 if (unlikely(ret < 0))
3219                         goto error;
3220         }
3221         func->function.os_desc_n =
3222                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3223
3224         /* And we're done */
3225         ffs_event_add(ffs, FUNCTIONFS_BIND);
3226         return 0;
3227
3228 error:
3229         /* XXX Do we need to release all claimed endpoints here? */
3230         return ret;
3231 }
3232
3233 static int ffs_func_bind(struct usb_configuration *c,
3234                          struct usb_function *f)
3235 {
3236         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3237         struct ffs_function *func = ffs_func_from_usb(f);
3238         int ret;
3239
3240         if (IS_ERR(ffs_opts))
3241                 return PTR_ERR(ffs_opts);
3242
3243         ret = _ffs_func_bind(c, f);
3244         if (ret && !--ffs_opts->refcnt)
3245                 functionfs_unbind(func->ffs);
3246
3247         return ret;
3248 }
3249
3250
3251 /* Other USB function hooks *************************************************/
3252
3253 static void ffs_reset_work(struct work_struct *work)
3254 {
3255         struct ffs_data *ffs = container_of(work,
3256                 struct ffs_data, reset_work);
3257         ffs_data_reset(ffs);
3258 }
3259
3260 static int ffs_func_set_alt(struct usb_function *f,
3261                             unsigned interface, unsigned alt)
3262 {
3263         struct ffs_function *func = ffs_func_from_usb(f);
3264         struct ffs_data *ffs = func->ffs;
3265         int ret = 0, intf;
3266
3267         if (alt != (unsigned)-1) {
3268                 intf = ffs_func_revmap_intf(func, interface);
3269                 if (unlikely(intf < 0))
3270                         return intf;
3271         }
3272
3273         if (ffs->func)
3274                 ffs_func_eps_disable(ffs->func);
3275
3276         if (ffs->state == FFS_DEACTIVATED) {
3277                 ffs->state = FFS_CLOSING;
3278                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3279                 schedule_work(&ffs->reset_work);
3280                 return -ENODEV;
3281         }
3282
3283         if (ffs->state != FFS_ACTIVE)
3284                 return -ENODEV;
3285
3286         if (alt == (unsigned)-1) {
3287                 ffs->func = NULL;
3288                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3289                 return 0;
3290         }
3291
3292         ffs->func = func;
3293         ret = ffs_func_eps_enable(func);
3294         if (likely(ret >= 0))
3295                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3296         return ret;
3297 }
3298
3299 static void ffs_func_disable(struct usb_function *f)
3300 {
3301         ffs_func_set_alt(f, 0, (unsigned)-1);
3302 }
3303
3304 static int ffs_func_setup(struct usb_function *f,
3305                           const struct usb_ctrlrequest *creq)
3306 {
3307         struct ffs_function *func = ffs_func_from_usb(f);
3308         struct ffs_data *ffs = func->ffs;
3309         unsigned long flags;
3310         int ret;
3311
3312         ENTER();
3313
3314         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3315         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3316         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3317         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3318         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3319
3320         /*
3321          * Most requests directed to interface go through here
3322          * (notable exceptions are set/get interface) so we need to
3323          * handle them.  All other either handled by composite or
3324          * passed to usb_configuration->setup() (if one is set).  No
3325          * matter, we will handle requests directed to endpoint here
3326          * as well (as it's straightforward).  Other request recipient
3327          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3328          * is being used.
3329          */
3330         if (ffs->state != FFS_ACTIVE)
3331                 return -ENODEV;
3332
3333         switch (creq->bRequestType & USB_RECIP_MASK) {
3334         case USB_RECIP_INTERFACE:
3335                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3336                 if (unlikely(ret < 0))
3337                         return ret;
3338                 break;
3339
3340         case USB_RECIP_ENDPOINT:
3341                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3342                 if (unlikely(ret < 0))
3343                         return ret;
3344                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3345                         ret = func->ffs->eps_addrmap[ret];
3346                 break;
3347
3348         default:
3349                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3350                         ret = le16_to_cpu(creq->wIndex);
3351                 else
3352                         return -EOPNOTSUPP;
3353         }
3354
3355         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3356         ffs->ev.setup = *creq;
3357         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3358         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3359         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3360
3361         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3362 }
3363
3364 static bool ffs_func_req_match(struct usb_function *f,
3365                                const struct usb_ctrlrequest *creq,
3366                                bool config0)
3367 {
3368         struct ffs_function *func = ffs_func_from_usb(f);
3369
3370         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3371                 return false;
3372
3373         switch (creq->bRequestType & USB_RECIP_MASK) {
3374         case USB_RECIP_INTERFACE:
3375                 return (ffs_func_revmap_intf(func,
3376                                              le16_to_cpu(creq->wIndex)) >= 0);
3377         case USB_RECIP_ENDPOINT:
3378                 return (ffs_func_revmap_ep(func,
3379                                            le16_to_cpu(creq->wIndex)) >= 0);
3380         default:
3381                 return (bool) (func->ffs->user_flags &
3382                                FUNCTIONFS_ALL_CTRL_RECIP);
3383         }
3384 }
3385
3386 static void ffs_func_suspend(struct usb_function *f)
3387 {
3388         ENTER();
3389         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3390 }
3391
3392 static void ffs_func_resume(struct usb_function *f)
3393 {
3394         ENTER();
3395         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3396 }
3397
3398
3399 /* Endpoint and interface numbers reverse mapping ***************************/
3400
3401 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3402 {
3403         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3404         return num ? num : -EDOM;
3405 }
3406
3407 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3408 {
3409         short *nums = func->interfaces_nums;
3410         unsigned count = func->ffs->interfaces_count;
3411
3412         for (; count; --count, ++nums) {
3413                 if (*nums >= 0 && *nums == intf)
3414                         return nums - func->interfaces_nums;
3415         }
3416
3417         return -EDOM;
3418 }
3419
3420
3421 /* Devices management *******************************************************/
3422
3423 static LIST_HEAD(ffs_devices);
3424
3425 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3426 {
3427         struct ffs_dev *dev;
3428
3429         if (!name)
3430                 return NULL;
3431
3432         list_for_each_entry(dev, &ffs_devices, entry) {
3433                 if (strcmp(dev->name, name) == 0)
3434                         return dev;
3435         }
3436
3437         return NULL;
3438 }
3439
3440 /*
3441  * ffs_lock must be taken by the caller of this function
3442  */
3443 static struct ffs_dev *_ffs_get_single_dev(void)
3444 {
3445         struct ffs_dev *dev;
3446
3447         if (list_is_singular(&ffs_devices)) {
3448                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3449                 if (dev->single)
3450                         return dev;
3451         }
3452
3453         return NULL;
3454 }
3455
3456 /*
3457  * ffs_lock must be taken by the caller of this function
3458  */
3459 static struct ffs_dev *_ffs_find_dev(const char *name)
3460 {
3461         struct ffs_dev *dev;
3462
3463         dev = _ffs_get_single_dev();
3464         if (dev)
3465                 return dev;
3466
3467         return _ffs_do_find_dev(name);
3468 }
3469
3470 /* Configfs support *********************************************************/
3471
3472 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3473 {
3474         return container_of(to_config_group(item), struct f_fs_opts,
3475                             func_inst.group);
3476 }
3477
3478 static void ffs_attr_release(struct config_item *item)
3479 {
3480         struct f_fs_opts *opts = to_ffs_opts(item);
3481
3482         usb_put_function_instance(&opts->func_inst);
3483 }
3484
3485 static struct configfs_item_operations ffs_item_ops = {
3486         .release        = ffs_attr_release,
3487 };
3488
3489 static const struct config_item_type ffs_func_type = {
3490         .ct_item_ops    = &ffs_item_ops,
3491         .ct_owner       = THIS_MODULE,
3492 };
3493
3494
3495 /* Function registration interface ******************************************/
3496
3497 static void ffs_free_inst(struct usb_function_instance *f)
3498 {
3499         struct f_fs_opts *opts;
3500
3501         opts = to_f_fs_opts(f);
3502         ffs_dev_lock();
3503         _ffs_free_dev(opts->dev);
3504         ffs_dev_unlock();
3505         kfree(opts);
3506 }
3507
3508 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3509 {
3510         if (strlen(name) >= sizeof_field(struct ffs_dev, name))
3511                 return -ENAMETOOLONG;
3512         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3513 }
3514
3515 static struct usb_function_instance *ffs_alloc_inst(void)
3516 {
3517         struct f_fs_opts *opts;
3518         struct ffs_dev *dev;
3519
3520         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3521         if (!opts)
3522                 return ERR_PTR(-ENOMEM);
3523
3524         opts->func_inst.set_inst_name = ffs_set_inst_name;
3525         opts->func_inst.free_func_inst = ffs_free_inst;
3526         ffs_dev_lock();
3527         dev = _ffs_alloc_dev();
3528         ffs_dev_unlock();
3529         if (IS_ERR(dev)) {
3530                 kfree(opts);
3531                 return ERR_CAST(dev);
3532         }
3533         opts->dev = dev;
3534         dev->opts = opts;
3535
3536         config_group_init_type_name(&opts->func_inst.group, "",
3537                                     &ffs_func_type);
3538         return &opts->func_inst;
3539 }
3540
3541 static void ffs_free(struct usb_function *f)
3542 {
3543         kfree(ffs_func_from_usb(f));
3544 }
3545
3546 static void ffs_func_unbind(struct usb_configuration *c,
3547                             struct usb_function *f)
3548 {
3549         struct ffs_function *func = ffs_func_from_usb(f);
3550         struct ffs_data *ffs = func->ffs;
3551         struct f_fs_opts *opts =
3552                 container_of(f->fi, struct f_fs_opts, func_inst);
3553         struct ffs_ep *ep = func->eps;
3554         unsigned count = ffs->eps_count;
3555         unsigned long flags;
3556
3557         ENTER();
3558         if (ffs->func == func) {
3559                 ffs_func_eps_disable(func);
3560                 ffs->func = NULL;
3561         }
3562
3563         if (!--opts->refcnt)
3564                 functionfs_unbind(ffs);
3565
3566         /* cleanup after autoconfig */
3567         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3568         while (count--) {
3569                 if (ep->ep && ep->req)
3570                         usb_ep_free_request(ep->ep, ep->req);
3571                 ep->req = NULL;
3572                 ++ep;
3573         }
3574         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3575         kfree(func->eps);
3576         func->eps = NULL;
3577         /*
3578          * eps, descriptors and interfaces_nums are allocated in the
3579          * same chunk so only one free is required.
3580          */
3581         func->function.fs_descriptors = NULL;
3582         func->function.hs_descriptors = NULL;
3583         func->function.ss_descriptors = NULL;
3584         func->interfaces_nums = NULL;
3585
3586         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3587 }
3588
3589 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3590 {
3591         struct ffs_function *func;
3592
3593         ENTER();
3594
3595         func = kzalloc(sizeof(*func), GFP_KERNEL);
3596         if (unlikely(!func))
3597                 return ERR_PTR(-ENOMEM);
3598
3599         func->function.name    = "Function FS Gadget";
3600
3601         func->function.bind    = ffs_func_bind;
3602         func->function.unbind  = ffs_func_unbind;
3603         func->function.set_alt = ffs_func_set_alt;
3604         func->function.disable = ffs_func_disable;
3605         func->function.setup   = ffs_func_setup;
3606         func->function.req_match = ffs_func_req_match;
3607         func->function.suspend = ffs_func_suspend;
3608         func->function.resume  = ffs_func_resume;
3609         func->function.free_func = ffs_free;
3610
3611         return &func->function;
3612 }
3613
3614 /*
3615  * ffs_lock must be taken by the caller of this function
3616  */
3617 static struct ffs_dev *_ffs_alloc_dev(void)
3618 {
3619         struct ffs_dev *dev;
3620         int ret;
3621
3622         if (_ffs_get_single_dev())
3623                         return ERR_PTR(-EBUSY);
3624
3625         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3626         if (!dev)
3627                 return ERR_PTR(-ENOMEM);
3628
3629         if (list_empty(&ffs_devices)) {
3630                 ret = functionfs_init();
3631                 if (ret) {
3632                         kfree(dev);
3633                         return ERR_PTR(ret);
3634                 }
3635         }
3636
3637         list_add(&dev->entry, &ffs_devices);
3638
3639         return dev;
3640 }
3641
3642 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3643 {
3644         struct ffs_dev *existing;
3645         int ret = 0;
3646
3647         ffs_dev_lock();
3648
3649         existing = _ffs_do_find_dev(name);
3650         if (!existing)
3651                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3652         else if (existing != dev)
3653                 ret = -EBUSY;
3654
3655         ffs_dev_unlock();
3656
3657         return ret;
3658 }
3659 EXPORT_SYMBOL_GPL(ffs_name_dev);
3660
3661 int ffs_single_dev(struct ffs_dev *dev)
3662 {
3663         int ret;
3664
3665         ret = 0;
3666         ffs_dev_lock();
3667
3668         if (!list_is_singular(&ffs_devices))
3669                 ret = -EBUSY;
3670         else
3671                 dev->single = true;
3672
3673         ffs_dev_unlock();
3674         return ret;
3675 }
3676 EXPORT_SYMBOL_GPL(ffs_single_dev);
3677
3678 /*
3679  * ffs_lock must be taken by the caller of this function
3680  */
3681 static void _ffs_free_dev(struct ffs_dev *dev)
3682 {
3683         list_del(&dev->entry);
3684
3685         /* Clear the private_data pointer to stop incorrect dev access */
3686         if (dev->ffs_data)
3687                 dev->ffs_data->private_data = NULL;
3688
3689         kfree(dev);
3690         if (list_empty(&ffs_devices))
3691                 functionfs_cleanup();
3692 }
3693
3694 static void *ffs_acquire_dev(const char *dev_name)
3695 {
3696         struct ffs_dev *ffs_dev;
3697
3698         ENTER();
3699         ffs_dev_lock();
3700
3701         ffs_dev = _ffs_find_dev(dev_name);
3702         if (!ffs_dev)
3703                 ffs_dev = ERR_PTR(-ENOENT);
3704         else if (ffs_dev->mounted)
3705                 ffs_dev = ERR_PTR(-EBUSY);
3706         else if (ffs_dev->ffs_acquire_dev_callback &&
3707             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3708                 ffs_dev = ERR_PTR(-ENOENT);
3709         else
3710                 ffs_dev->mounted = true;
3711
3712         ffs_dev_unlock();
3713         return ffs_dev;
3714 }
3715
3716 static void ffs_release_dev(struct ffs_data *ffs_data)
3717 {
3718         struct ffs_dev *ffs_dev;
3719
3720         ENTER();
3721         ffs_dev_lock();
3722
3723         ffs_dev = ffs_data->private_data;
3724         if (ffs_dev) {
3725                 ffs_dev->mounted = false;
3726
3727                 if (ffs_dev->ffs_release_dev_callback)
3728                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3729         }
3730
3731         ffs_dev_unlock();
3732 }
3733
3734 static int ffs_ready(struct ffs_data *ffs)
3735 {
3736         struct ffs_dev *ffs_obj;
3737         int ret = 0;
3738
3739         ENTER();
3740         ffs_dev_lock();
3741
3742         ffs_obj = ffs->private_data;
3743         if (!ffs_obj) {
3744                 ret = -EINVAL;
3745                 goto done;
3746         }
3747         if (WARN_ON(ffs_obj->desc_ready)) {
3748                 ret = -EBUSY;
3749                 goto done;
3750         }
3751
3752         ffs_obj->desc_ready = true;
3753         ffs_obj->ffs_data = ffs;
3754
3755         if (ffs_obj->ffs_ready_callback) {
3756                 ret = ffs_obj->ffs_ready_callback(ffs);
3757                 if (ret)
3758                         goto done;
3759         }
3760
3761         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3762 done:
3763         ffs_dev_unlock();
3764         return ret;
3765 }
3766
3767 static void ffs_closed(struct ffs_data *ffs)
3768 {
3769         struct ffs_dev *ffs_obj;
3770         struct f_fs_opts *opts;
3771         struct config_item *ci;
3772
3773         ENTER();
3774         ffs_dev_lock();
3775
3776         ffs_obj = ffs->private_data;
3777         if (!ffs_obj)
3778                 goto done;
3779
3780         ffs_obj->desc_ready = false;
3781         ffs_obj->ffs_data = NULL;
3782
3783         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3784             ffs_obj->ffs_closed_callback)
3785                 ffs_obj->ffs_closed_callback(ffs);
3786
3787         if (ffs_obj->opts)
3788                 opts = ffs_obj->opts;
3789         else
3790                 goto done;
3791
3792         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3793             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3794                 goto done;
3795
3796         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3797         ffs_dev_unlock();
3798
3799         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3800                 unregister_gadget_item(ci);
3801         return;
3802 done:
3803         ffs_dev_unlock();
3804 }
3805
3806 /* Misc helper functions ****************************************************/
3807
3808 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3809 {
3810         return nonblock
3811                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3812                 : mutex_lock_interruptible(mutex);
3813 }
3814
3815 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3816 {
3817         char *data;
3818
3819         if (unlikely(!len))
3820                 return NULL;
3821
3822         data = kmalloc(len, GFP_KERNEL);
3823         if (unlikely(!data))
3824                 return ERR_PTR(-ENOMEM);
3825
3826         if (unlikely(copy_from_user(data, buf, len))) {
3827                 kfree(data);
3828                 return ERR_PTR(-EFAULT);
3829         }
3830
3831         pr_vdebug("Buffer from user space:\n");
3832         ffs_dump_mem("", data, len);
3833
3834         return data;
3835 }
3836
3837 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3838 MODULE_LICENSE("GPL");
3839 MODULE_AUTHOR("Michal Nazarewicz");