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 <[email protected]>
   7  *
   8  * Based on inode.c (GadgetFS) which was:
   9  * Copyright (C) 2003-2004 David Brownell
  10  * Copyright (C) 2003 Agilent Technologies
  11  */
  12
  13
  14 /* #define DEBUG */
  15 /* #define VERBOSE_DEBUG */
  16
  17 #include <linux/blkdev.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/export.h>
  20 #include <linux/hid.h>
  21 #include <linux/mm.h>
  22 #include <linux/module.h>
  23 #include <linux/scatterlist.h>
  24 #include <linux/sched/signal.h>
  25 #include <linux/uio.h>
  26 #include <linux/vmalloc.h>
  27 #include <asm/unaligned.h>
  28
  29 #include <linux/usb/ccid.h>
  30 #include <linux/usb/composite.h>
  31 #include <linux/usb/functionfs.h>
  32
  33 #include <linux/aio.h>
  34 #include <linux/mmu_context.h>
  35 #include <linux/poll.h>
  36 #include <linux/eventfd.h>
  37
  38 #include "u_fs.h"
  39 #include "u_f.h"
  40 #include "u_os_desc.h"
  41 #include "configfs.h"
  42
  43 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  44
  45 /* Reference counter handling */
  46 static void ffs_data_get(struct ffs_data *ffs);
  47 static void ffs_data_put(struct ffs_data *ffs);
  48 /* Creates new ffs_data object. */
  49 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  50         __attribute__((malloc));
  51
  52 /* Opened counter handling. */
  53 static void ffs_data_opened(struct ffs_data *ffs);
  54 static void ffs_data_closed(struct ffs_data *ffs);
  55
  56 /* Called with ffs->mutex held; take over ownership of data. */
  57 static int __must_check
  58 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  59 static int __must_check
  60 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  61
  62
  63 /* The function structure ***************************************************/
  64
  65 struct ffs_ep;
  66
  67 struct ffs_function {
  68         struct usb_configuration        *conf;
  69         struct usb_gadget               *gadget;
  70         struct ffs_data                 *ffs;
  71
  72         struct ffs_ep                   *eps;
  73         u8                              eps_revmap[16];
  74         short                           *interfaces_nums;
  75
  76         struct usb_function             function;
  77 };
  78
  79
  80 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  81 {
  82         return container_of(f, struct ffs_function, function);
  83 }
  84
  85
  86 static inline enum ffs_setup_state
  87 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  88 {
  89         return (enum ffs_setup_state)
  90                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  91 }
  92
  93
  94 static void ffs_func_eps_disable(struct ffs_function *func);
  95 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  96
  97 static int ffs_func_bind(struct usb_configuration *,
  98                          struct usb_function *);
  99 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 100 static void ffs_func_disable(struct usb_function *);
 101 static int ffs_func_setup(struct usb_function *,
 102                           const struct usb_ctrlrequest *);
 103 static bool ffs_func_req_match(struct usb_function *,
 104                                const struct usb_ctrlrequest *,
 105                                bool config0);
 106 static void ffs_func_suspend(struct usb_function *);
 107 static void ffs_func_resume(struct usb_function *);
 108
 109
 110 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 111 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 112
 113
 114 /* The endpoints structures *************************************************/
 115
 116 struct ffs_ep {
 117         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 118         struct usb_request              *req;   /* P: epfile->mutex */
 119
 120         /* [0]: full speed, [1]: high speed, [2]: super speed */
 121         struct usb_endpoint_descriptor  *descs[3];
 122
 123         u8                              num;
 124
 125         int                             status; /* P: epfile->mutex */
 126 };
 127
 128 struct ffs_epfile {
 129         /* Protects ep->ep and ep->req. */
 130         struct mutex                    mutex;
 131
 132         struct ffs_data                 *ffs;
 133         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 134
 135         struct dentry                   *dentry;
 136
 137         /*
 138          * Buffer for holding data from partial reads which may happen since
 139          * we’re rounding user read requests to a multiple of a max packet size.
 140          *
 141          * The pointer is initialised with NULL value and may be set by
 142          * __ffs_epfile_read_data function to point to a temporary buffer.
 143          *
 144          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 145          * data from said buffer and eventually free it.  Importantly, while the
 146          * function is using the buffer, it sets the pointer to NULL.  This is
 147          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 148          * can never run concurrently (they are synchronised by epfile->mutex)
 149          * so the latter will not assign a new value to the pointer.
 150          *
 151          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 152          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 153          * value is crux of the synchronisation between ffs_func_eps_disable and
 154          * __ffs_epfile_read_data.
 155          *
 156          * Once __ffs_epfile_read_data is about to finish it will try to set the
 157          * pointer back to its old value (as described above), but seeing as the
 158          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 159          * the buffer.
 160          *
 161          * == State transitions ==
 162          *
 163          * • ptr == NULL:  (initial state)
 164          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 165          *   ◦ __ffs_epfile_read_buffered:    nop
 166          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 167          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 168          * • ptr == DROP:
 169          *   ◦ __ffs_epfile_read_buffer_free: nop
 170          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 171          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 172          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 173          * • ptr == buf:
 174          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 175          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 176          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 177          *                                    is always called first
 178          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 179          * • ptr == NULL and reading:
 180          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 181          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 182          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 183          *   ◦ reading finishes and …
 184          *     … all data read:               free buf, go to ptr == NULL
 185          *     … otherwise:                   go to ptr == buf and reading
 186          * • ptr == DROP and reading:
 187          *   ◦ __ffs_epfile_read_buffer_free: nop
 188          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 189          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 190          *   ◦ reading finishes:              free buf, go to ptr == DROP
 191          */
 192         struct ffs_buffer               *read_buffer;
 193 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 194
 195         char                            name[5];
 196
 197         unsigned char                   in;     /* P: ffs->eps_lock */
 198         unsigned char                   isoc;   /* P: ffs->eps_lock */
 199
 200         unsigned char                   _pad;
 201 };
 202
 203 struct ffs_buffer {
 204         size_t length;
 205         char *data;
 206         char storage[];
 207 };
 208
 209 /*  ffs_io_data structure ***************************************************/
 210
 211 struct ffs_io_data {
 212         bool aio;
 213         bool read;
 214
 215         struct kiocb *kiocb;
 216         struct iov_iter data;
 217         const void *to_free;
 218         char *buf;
 219
 220         struct mm_struct *mm;
 221         struct work_struct work;
 222
 223         struct usb_ep *ep;
 224         struct usb_request *req;
 225         struct sg_table sgt;
 226         bool use_sg;
 227
 228         struct ffs_data *ffs;
 229 };
 230
 231 struct ffs_desc_helper {
 232         struct ffs_data *ffs;
 233         unsigned interfaces_count;
 234         unsigned eps_count;
 235 };
 236
 237 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 238 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 239
 240 static struct dentry *
 241 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 242                    const struct file_operations *fops);
 243
 244 /* Devices management *******************************************************/
 245
 246 DEFINE_MUTEX(ffs_lock);
 247 EXPORT_SYMBOL_GPL(ffs_lock);
 248
 249 static struct ffs_dev *_ffs_find_dev(const char *name);
 250 static struct ffs_dev *_ffs_alloc_dev(void);
 251 static void _ffs_free_dev(struct ffs_dev *dev);
 252 static void *ffs_acquire_dev(const char *dev_name);
 253 static void ffs_release_dev(struct ffs_data *ffs_data);
 254 static int ffs_ready(struct ffs_data *ffs);
 255 static void ffs_closed(struct ffs_data *ffs);
 256
 257 /* Misc helper functions ****************************************************/
 258
 259 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 260         __attribute__((warn_unused_result, nonnull));
 261 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 262         __attribute__((warn_unused_result, nonnull));
 263
 264
 265 /* Control file aka ep0 *****************************************************/
 266
 267 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 268 {
 269         struct ffs_data *ffs = req->context;
 270
 271         complete(&ffs->ep0req_completion);
 272 }
 273
 274 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 275         __releases(&ffs->ev.waitq.lock)
 276 {
 277         struct usb_request *req = ffs->ep0req;
 278         int ret;
 279
 280         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 281
 282         spin_unlock_irq(&ffs->ev.waitq.lock);
 283
 284         req->buf      = data;
 285         req->length   = len;
 286
 287         /*
 288          * UDC layer requires to provide a buffer even for ZLP, but should
 289          * not use it at all. Let's provide some poisoned pointer to catch
 290          * possible bug in the driver.
 291          */
 292         if (req->buf == NULL)
 293                 req->buf = (void *)0xDEADBABE;
 294
 295         reinit_completion(&ffs->ep0req_completion);
 296
 297         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 298         if (unlikely(ret < 0))
 299                 return ret;
 300
 301         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 302         if (unlikely(ret)) {
 303                 usb_ep_dequeue(ffs->gadget->ep0, req);
 304                 return -EINTR;
 305         }
 306
 307         ffs->setup_state = FFS_NO_SETUP;
 308         return req->status ? req->status : req->actual;
 309 }
 310
 311 static int __ffs_ep0_stall(struct ffs_data *ffs)
 312 {
 313         if (ffs->ev.can_stall) {
 314                 pr_vdebug("ep0 stall\n");
 315                 usb_ep_set_halt(ffs->gadget->ep0);
 316                 ffs->setup_state = FFS_NO_SETUP;
 317                 return -EL2HLT;
 318         } else {
 319                 pr_debug("bogus ep0 stall!\n");
 320                 return -ESRCH;
 321         }
 322 }
 323
 324 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 325                              size_t len, loff_t *ptr)
 326 {
 327         struct ffs_data *ffs = file->private_data;
 328         ssize_t ret;
 329         char *data;
 330
 331         ENTER();
 332
 333         /* Fast check if setup was canceled */
 334         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 335                 return -EIDRM;
 336
 337         /* Acquire mutex */
 338         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 339         if (unlikely(ret < 0))
 340                 return ret;
 341
 342         /* Check state */
 343         switch (ffs->state) {
 344         case FFS_READ_DESCRIPTORS:
 345         case FFS_READ_STRINGS:
 346                 /* Copy data */
 347                 if (unlikely(len < 16)) {
 348                         ret = -EINVAL;
 349                         break;
 350                 }
 351
 352                 data = ffs_prepare_buffer(buf, len);
 353                 if (IS_ERR(data)) {
 354                         ret = PTR_ERR(data);
 355                         break;
 356                 }
 357
 358                 /* Handle data */
 359                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 360                         pr_info("read descriptors\n");
 361                         ret = __ffs_data_got_descs(ffs, data, len);
 362                         if (unlikely(ret < 0))
 363                                 break;
 364
 365                         ffs->state = FFS_READ_STRINGS;
 366                         ret = len;
 367                 } else {
 368                         pr_info("read strings\n");
 369                         ret = __ffs_data_got_strings(ffs, data, len);
 370                         if (unlikely(ret < 0))
 371                                 break;
 372
 373                         ret = ffs_epfiles_create(ffs);
 374                         if (unlikely(ret)) {
 375                                 ffs->state = FFS_CLOSING;
 376                                 break;
 377                         }
 378
 379                         ffs->state = FFS_ACTIVE;
 380                         mutex_unlock(&ffs->mutex);
 381
 382                         ret = ffs_ready(ffs);
 383                         if (unlikely(ret < 0)) {
 384                                 ffs->state = FFS_CLOSING;
 385                                 return ret;
 386                         }
 387
 388                         return len;
 389                 }
 390                 break;
 391
 392         case FFS_ACTIVE:
 393                 data = NULL;
 394                 /*
 395                  * We're called from user space, we can use _irq
 396                  * rather then _irqsave
 397                  */
 398                 spin_lock_irq(&ffs->ev.waitq.lock);
 399                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 400                 case FFS_SETUP_CANCELLED:
 401                         ret = -EIDRM;
 402                         goto done_spin;
 403
 404                 case FFS_NO_SETUP:
 405                         ret = -ESRCH;
 406                         goto done_spin;
 407
 408                 case FFS_SETUP_PENDING:
 409                         break;
 410                 }
 411
 412                 /* FFS_SETUP_PENDING */
 413                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 414                         spin_unlock_irq(&ffs->ev.waitq.lock);
 415                         ret = __ffs_ep0_stall(ffs);
 416                         break;
 417                 }
 418
 419                 /* FFS_SETUP_PENDING and not stall */
 420                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 421
 422                 spin_unlock_irq(&ffs->ev.waitq.lock);
 423
 424                 data = ffs_prepare_buffer(buf, len);
 425                 if (IS_ERR(data)) {
 426                         ret = PTR_ERR(data);
 427                         break;
 428                 }
 429
 430                 spin_lock_irq(&ffs->ev.waitq.lock);
 431
 432                 /*
 433                  * We are guaranteed to be still in FFS_ACTIVE state
 434                  * but the state of setup could have changed from
 435                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 436                  * to check for that.  If that happened we copied data
 437                  * from user space in vain but it's unlikely.
 438                  *
 439                  * For sure we are not in FFS_NO_SETUP since this is
 440                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 441                  * transition can be performed and it's protected by
 442                  * mutex.
 443                  */
 444                 if (ffs_setup_state_clear_cancelled(ffs) ==
 445                     FFS_SETUP_CANCELLED) {
 446                         ret = -EIDRM;
 447 done_spin:
 448                         spin_unlock_irq(&ffs->ev.waitq.lock);
 449                 } else {
 450                         /* unlocks spinlock */
 451                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 452                 }
 453                 kfree(data);
 454                 break;
 455
 456         default:
 457                 ret = -EBADFD;
 458                 break;
 459         }
 460
 461         mutex_unlock(&ffs->mutex);
 462         return ret;
 463 }
 464
 465 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 466 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 467                                      size_t n)
 468         __releases(&ffs->ev.waitq.lock)
 469 {
 470         /*
 471          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 472          * size of ffs->ev.types array (which is four) so that's how much space
 473          * we reserve.
 474          */
 475         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 476         const size_t size = n * sizeof *events;
 477         unsigned i = 0;
 478
 479         memset(events, 0, size);
 480
 481         do {
 482                 events[i].type = ffs->ev.types[i];
 483                 if (events[i].type == FUNCTIONFS_SETUP) {
 484                         events[i].u.setup = ffs->ev.setup;
 485                         ffs->setup_state = FFS_SETUP_PENDING;
 486                 }
 487         } while (++i < n);
 488
 489         ffs->ev.count -= n;
 490         if (ffs->ev.count)
 491                 memmove(ffs->ev.types, ffs->ev.types + n,
 492                         ffs->ev.count * sizeof *ffs->ev.types);
 493
 494         spin_unlock_irq(&ffs->ev.waitq.lock);
 495         mutex_unlock(&ffs->mutex);
 496
 497         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 498 }
 499
 500 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 501                             size_t len, loff_t *ptr)
 502 {
 503         struct ffs_data *ffs = file->private_data;
 504         char *data = NULL;
 505         size_t n;
 506         int ret;
 507
 508         ENTER();
 509
 510         /* Fast check if setup was canceled */
 511         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 512                 return -EIDRM;
 513
 514         /* Acquire mutex */
 515         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 516         if (unlikely(ret < 0))
 517                 return ret;
 518
 519         /* Check state */
 520         if (ffs->state != FFS_ACTIVE) {
 521                 ret = -EBADFD;
 522                 goto done_mutex;
 523         }
 524
 525         /*
 526          * We're called from user space, we can use _irq rather then
 527          * _irqsave
 528          */
 529         spin_lock_irq(&ffs->ev.waitq.lock);
 530
 531         switch (ffs_setup_state_clear_cancelled(ffs)) {
 532         case FFS_SETUP_CANCELLED:
 533                 ret = -EIDRM;
 534                 break;
 535
 536         case FFS_NO_SETUP:
 537                 n = len / sizeof(struct usb_functionfs_event);
 538                 if (unlikely(!n)) {
 539                         ret = -EINVAL;
 540                         break;
 541                 }
 542
 543                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 544                         ret = -EAGAIN;
 545                         break;
 546                 }
 547
 548                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 549                                                         ffs->ev.count)) {
 550                         ret = -EINTR;
 551                         break;
 552                 }
 553
 554                 /* unlocks spinlock */
 555                 return __ffs_ep0_read_events(ffs, buf,
 556                                              min(n, (size_t)ffs->ev.count));
 557
 558         case FFS_SETUP_PENDING:
 559                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 560                         spin_unlock_irq(&ffs->ev.waitq.lock);
 561                         ret = __ffs_ep0_stall(ffs);
 562                         goto done_mutex;
 563                 }
 564
 565                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 566
 567                 spin_unlock_irq(&ffs->ev.waitq.lock);
 568
 569                 if (likely(len)) {
 570                         data = kmalloc(len, GFP_KERNEL);
 571                         if (unlikely(!data)) {
 572                                 ret = -ENOMEM;
 573                                 goto done_mutex;
 574                         }
 575                 }
 576
 577                 spin_lock_irq(&ffs->ev.waitq.lock);
 578
 579                 /* See ffs_ep0_write() */
 580                 if (ffs_setup_state_clear_cancelled(ffs) ==
 581                     FFS_SETUP_CANCELLED) {
 582                         ret = -EIDRM;
 583                         break;
 584                 }
 585
 586                 /* unlocks spinlock */
 587                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 588                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 589                         ret = -EFAULT;
 590                 goto done_mutex;
 591
 592         default:
 593                 ret = -EBADFD;
 594                 break;
 595         }
 596
 597         spin_unlock_irq(&ffs->ev.waitq.lock);
 598 done_mutex:
 599         mutex_unlock(&ffs->mutex);
 600         kfree(data);
 601         return ret;
 602 }
 603
 604 static int ffs_ep0_open(struct inode *inode, struct file *file)
 605 {
 606         struct ffs_data *ffs = inode->i_private;
 607
 608         ENTER();
 609
 610         if (unlikely(ffs->state == FFS_CLOSING))
 611                 return -EBUSY;
 612
 613         file->private_data = ffs;
 614         ffs_data_opened(ffs);
 615
 616         return 0;
 617 }
 618
 619 static int ffs_ep0_release(struct inode *inode, struct file *file)
 620 {
 621         struct ffs_data *ffs = file->private_data;
 622
 623         ENTER();
 624
 625         ffs_data_closed(ffs);
 626
 627         return 0;
 628 }
 629
 630 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 631 {
 632         struct ffs_data *ffs = file->private_data;
 633         struct usb_gadget *gadget = ffs->gadget;
 634         long ret;
 635
 636         ENTER();
 637
 638         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 639                 struct ffs_function *func = ffs->func;
 640                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 641         } else if (gadget && gadget->ops->ioctl) {
 642                 ret = gadget->ops->ioctl(gadget, code, value);
 643         } else {
 644                 ret = -ENOTTY;
 645         }
 646
 647         return ret;
 648 }
 649
 650 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 651 {
 652         struct ffs_data *ffs = file->private_data;
 653         __poll_t mask = EPOLLWRNORM;
 654         int ret;
 655
 656         poll_wait(file, &ffs->ev.waitq, wait);
 657
 658         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 659         if (unlikely(ret < 0))
 660                 return mask;
 661
 662         switch (ffs->state) {
 663         case FFS_READ_DESCRIPTORS:
 664         case FFS_READ_STRINGS:
 665                 mask |= EPOLLOUT;
 666                 break;
 667
 668         case FFS_ACTIVE:
 669                 switch (ffs->setup_state) {
 670                 case FFS_NO_SETUP:
 671                         if (ffs->ev.count)
 672                                 mask |= EPOLLIN;
 673                         break;
 674
 675                 case FFS_SETUP_PENDING:
 676                 case FFS_SETUP_CANCELLED:
 677                         mask |= (EPOLLIN | EPOLLOUT);
 678                         break;
 679                 }
 680         case FFS_CLOSING:
 681                 break;
 682         case FFS_DEACTIVATED:
 683                 break;
 684         }
 685
 686         mutex_unlock(&ffs->mutex);
 687
 688         return mask;
 689 }
 690
 691 static const struct file_operations ffs_ep0_operations = {
 692         .llseek =       no_llseek,
 693
 694         .open =         ffs_ep0_open,
 695         .write =        ffs_ep0_write,
 696         .read =         ffs_ep0_read,
 697         .release =      ffs_ep0_release,
 698         .unlocked_ioctl =       ffs_ep0_ioctl,
 699         .poll =         ffs_ep0_poll,
 700 };
 701
 702
 703 /* "Normal" endpoints operations ********************************************/
 704
 705 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 706 {
 707         ENTER();
 708         if (likely(req->context)) {
 709                 struct ffs_ep *ep = _ep->driver_data;
 710                 ep->status = req->status ? req->status : req->actual;
 711                 complete(req->context);
 712         }
 713 }
 714
 715 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 716 {
 717         ssize_t ret = copy_to_iter(data, data_len, iter);
 718         if (likely(ret == data_len))
 719                 return ret;
 720
 721         if (unlikely(iov_iter_count(iter)))
 722                 return -EFAULT;
 723
 724         /*
 725          * Dear user space developer!
 726          *
 727          * TL;DR: To stop getting below error message in your kernel log, change
 728          * user space code using functionfs to align read buffers to a max
 729          * packet size.
 730          *
 731          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 732          * packet size.  When unaligned buffer is passed to functionfs, it
 733          * internally uses a larger, aligned buffer so that such UDCs are happy.
 734          *
 735          * Unfortunately, this means that host may send more data than was
 736          * requested in read(2) system call.  f_fs doesn’t know what to do with
 737          * that excess data so it simply drops it.
 738          *
 739          * Was the buffer aligned in the first place, no such problem would
 740          * happen.
 741          *
 742          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 743          * by splitting a request into multiple parts.  This splitting may still
 744          * be a problem though so it’s likely best to align the buffer
 745          * regardless of it being AIO or not..
 746          *
 747          * This only affects OUT endpoints, i.e. reading data with a read(2),
 748          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 749          * affected.
 750          */
 751         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 752                "Align read buffer size to max packet size to avoid the problem.\n",
 753                data_len, ret);
 754
 755         return ret;
 756 }
 757
 758 /*
 759  * allocate a virtually contiguous buffer and create a scatterlist describing it
 760  * @sg_table    - pointer to a place to be filled with sg_table contents
 761  * @size        - required buffer size
 762  */
 763 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 764 {
 765         struct page **pages;
 766         void *vaddr, *ptr;
 767         unsigned int n_pages;
 768         int i;
 769
 770         vaddr = vmalloc(sz);
 771         if (!vaddr)
 772                 return NULL;
 773
 774         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 775         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 776         if (!pages) {
 777                 vfree(vaddr);
 778
 779                 return NULL;
 780         }
 781         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 782                 pages[i] = vmalloc_to_page(ptr);
 783
 784         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 785                 kvfree(pages);
 786                 vfree(vaddr);
 787
 788                 return NULL;
 789         }
 790         kvfree(pages);
 791
 792         return vaddr;
 793 }
 794
 795 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 796         size_t data_len)
 797 {
 798         if (io_data->use_sg)
 799                 return ffs_build_sg_list(&io_data->sgt, data_len);
 800
 801         return kmalloc(data_len, GFP_KERNEL);
 802 }
 803
 804 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 805 {
 806         if (!io_data->buf)
 807                 return;
 808
 809         if (io_data->use_sg) {
 810                 sg_free_table(&io_data->sgt);
 811                 vfree(io_data->buf);
 812         } else {
 813                 kfree(io_data->buf);
 814         }
 815 }
 816
 817 static void ffs_user_copy_worker(struct work_struct *work)
 818 {
 819         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 820                                                    work);
 821         int ret = io_data->req->status ? io_data->req->status :
 822                                          io_data->req->actual;
 823         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 824
 825         if (io_data->read && ret > 0) {
 826                 mm_segment_t oldfs = get_fs();
 827
 828                 set_fs(USER_DS);
 829                 use_mm(io_data->mm);
 830                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 831                 unuse_mm(io_data->mm);
 832                 set_fs(oldfs);
 833         }
 834
 835         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 836
 837         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 838                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 839
 840         usb_ep_free_request(io_data->ep, io_data->req);
 841
 842         if (io_data->read)
 843                 kfree(io_data->to_free);
 844         ffs_free_buffer(io_data);
 845         kfree(io_data);
 846 }
 847
 848 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 849                                          struct usb_request *req)
 850 {
 851         struct ffs_io_data *io_data = req->context;
 852         struct ffs_data *ffs = io_data->ffs;
 853
 854         ENTER();
 855
 856         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 857         queue_work(ffs->io_completion_wq, &io_data->work);
 858 }
 859
 860 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 861 {
 862         /*
 863          * See comment in struct ffs_epfile for full read_buffer pointer
 864          * synchronisation story.
 865          */
 866         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 867         if (buf && buf != READ_BUFFER_DROP)
 868                 kfree(buf);
 869 }
 870
 871 /* Assumes epfile->mutex is held. */
 872 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 873                                           struct iov_iter *iter)
 874 {
 875         /*
 876          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 877          * the buffer while we are using it.  See comment in struct ffs_epfile
 878          * for full read_buffer pointer synchronisation story.
 879          */
 880         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 881         ssize_t ret;
 882         if (!buf || buf == READ_BUFFER_DROP)
 883                 return 0;
 884
 885         ret = copy_to_iter(buf->data, buf->length, iter);
 886         if (buf->length == ret) {
 887                 kfree(buf);
 888                 return ret;
 889         }
 890
 891         if (unlikely(iov_iter_count(iter))) {
 892                 ret = -EFAULT;
 893         } else {
 894                 buf->length -= ret;
 895                 buf->data += ret;
 896         }
 897
 898         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 899                 kfree(buf);
 900
 901         return ret;
 902 }
 903
 904 /* Assumes epfile->mutex is held. */
 905 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 906                                       void *data, int data_len,
 907                                       struct iov_iter *iter)
 908 {
 909         struct ffs_buffer *buf;
 910
 911         ssize_t ret = copy_to_iter(data, data_len, iter);
 912         if (likely(data_len == ret))
 913                 return ret;
 914
 915         if (unlikely(iov_iter_count(iter)))
 916                 return -EFAULT;
 917
 918         /* See ffs_copy_to_iter for more context. */
 919         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 920                 data_len, ret);
 921
 922         data_len -= ret;
 923         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 924         if (!buf)
 925                 return -ENOMEM;
 926         buf->length = data_len;
 927         buf->data = buf->storage;
 928         memcpy(buf->storage, data + ret, data_len);
 929
 930         /*
 931          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 932          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 933          * in struct ffs_epfile for full read_buffer pointer synchronisation
 934          * story.
 935          */
 936         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 937                 kfree(buf);
 938
 939         return ret;
 940 }
 941
 942 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 943 {
 944         struct ffs_epfile *epfile = file->private_data;
 945         struct usb_request *req;
 946         struct ffs_ep *ep;
 947         char *data = NULL;
 948         ssize_t ret, data_len = -EINVAL;
 949         int halt;
 950
 951         /* Are we still active? */
 952         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 953                 return -ENODEV;
 954
 955         /* Wait for endpoint to be enabled */
 956         ep = epfile->ep;
 957         if (!ep) {
 958                 if (file->f_flags & O_NONBLOCK)
 959                         return -EAGAIN;
 960
 961                 ret = wait_event_interruptible(
 962                                 epfile->ffs->wait, (ep = epfile->ep));
 963                 if (ret)
 964                         return -EINTR;
 965         }
 966
 967         /* Do we halt? */
 968         halt = (!io_data->read == !epfile->in);
 969         if (halt && epfile->isoc)
 970                 return -EINVAL;
 971
 972         /* We will be using request and read_buffer */
 973         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 974         if (unlikely(ret))
 975                 goto error;
 976
 977         /* Allocate & copy */
 978         if (!halt) {
 979                 struct usb_gadget *gadget;
 980
 981                 /*
 982                  * Do we have buffered data from previous partial read?  Check
 983                  * that for synchronous case only because we do not have
 984                  * facility to ‘wake up’ a pending asynchronous read and push
 985                  * buffered data to it which we would need to make things behave
 986                  * consistently.
 987                  */
 988                 if (!io_data->aio && io_data->read) {
 989                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 990                         if (ret)
 991                                 goto error_mutex;
 992                 }
 993
 994                 /*
 995                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 996                  * before the waiting completes, so do not assign to 'gadget'
 997                  * earlier
 998                  */
 999                 gadget = epfile->ffs->gadget;
1000                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1001
1002                 spin_lock_irq(&epfile->ffs->eps_lock);
1003                 /* In the meantime, endpoint got disabled or changed. */
1004                 if (epfile->ep != ep) {
1005                         ret = -ESHUTDOWN;
1006                         goto error_lock;
1007                 }
1008                 data_len = iov_iter_count(&io_data->data);
1009                 /*
1010                  * Controller may require buffer size to be aligned to
1011                  * maxpacketsize of an out endpoint.
1012                  */
1013                 if (io_data->read)
1014                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1015                 spin_unlock_irq(&epfile->ffs->eps_lock);
1016
1017                 data = ffs_alloc_buffer(io_data, data_len);
1018                 if (unlikely(!data)) {
1019                         ret = -ENOMEM;
1020                         goto error_mutex;
1021                 }
1022                 if (!io_data->read &&
1023                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1024                         ret = -EFAULT;
1025                         goto error_mutex;
1026                 }
1027         }
1028
1029         spin_lock_irq(&epfile->ffs->eps_lock);
1030
1031         if (epfile->ep != ep) {
1032                 /* In the meantime, endpoint got disabled or changed. */
1033                 ret = -ESHUTDOWN;
1034         } else if (halt) {
1035                 ret = usb_ep_set_halt(ep->ep);
1036                 if (!ret)
1037                         ret = -EBADMSG;
1038         } else if (unlikely(data_len == -EINVAL)) {
1039                 /*
1040                  * Sanity Check: even though data_len can't be used
1041                  * uninitialized at the time I write this comment, some
1042                  * compilers complain about this situation.
1043                  * In order to keep the code clean from warnings, data_len is
1044                  * being initialized to -EINVAL during its declaration, which
1045                  * means we can't rely on compiler anymore to warn no future
1046                  * changes won't result in data_len being used uninitialized.
1047                  * For such reason, we're adding this redundant sanity check
1048                  * here.
1049                  */
1050                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1051                 ret = -EINVAL;
1052         } else if (!io_data->aio) {
1053                 DECLARE_COMPLETION_ONSTACK(done);
1054                 bool interrupted = false;
1055
1056                 req = ep->req;
1057                 if (io_data->use_sg) {
1058                         req->buf = NULL;
1059                         req->sg = io_data->sgt.sgl;
1060                         req->num_sgs = io_data->sgt.nents;
1061                 } else {
1062                         req->buf = data;
1063                 }
1064                 req->length = data_len;
1065
1066                 io_data->buf = data;
1067
1068                 req->context  = &done;
1069                 req->complete = ffs_epfile_io_complete;
1070
1071                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1072                 if (unlikely(ret < 0))
1073                         goto error_lock;
1074
1075                 spin_unlock_irq(&epfile->ffs->eps_lock);
1076
1077                 if (unlikely(wait_for_completion_interruptible(&done))) {
1078                         /*
1079                          * To avoid race condition with ffs_epfile_io_complete,
1080                          * dequeue the request first then check
1081                          * status. usb_ep_dequeue API should guarantee no race
1082                          * condition with req->complete callback.
1083                          */
1084                         usb_ep_dequeue(ep->ep, req);
1085                         wait_for_completion(&done);
1086                         interrupted = ep->status < 0;
1087                 }
1088
1089                 if (interrupted)
1090                         ret = -EINTR;
1091                 else if (io_data->read && ep->status > 0)
1092                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1093                                                      &io_data->data);
1094                 else
1095                         ret = ep->status;
1096                 goto error_mutex;
1097         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1098                 ret = -ENOMEM;
1099         } else {
1100                 if (io_data->use_sg) {
1101                         req->buf = NULL;
1102                         req->sg = io_data->sgt.sgl;
1103                         req->num_sgs = io_data->sgt.nents;
1104                 } else {
1105                         req->buf = data;
1106                 }
1107                 req->length = data_len;
1108
1109                 io_data->buf = data;
1110                 io_data->ep = ep->ep;
1111                 io_data->req = req;
1112                 io_data->ffs = epfile->ffs;
1113
1114                 req->context  = io_data;
1115                 req->complete = ffs_epfile_async_io_complete;
1116
1117                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1118                 if (unlikely(ret)) {
1119                         usb_ep_free_request(ep->ep, req);
1120                         goto error_lock;
1121                 }
1122
1123                 ret = -EIOCBQUEUED;
1124                 /*
1125                  * Do not kfree the buffer in this function.  It will be freed
1126                  * by ffs_user_copy_worker.
1127                  */
1128                 data = NULL;
1129         }
1130
1131 error_lock:
1132         spin_unlock_irq(&epfile->ffs->eps_lock);
1133 error_mutex:
1134         mutex_unlock(&epfile->mutex);
1135 error:
1136         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1137                 ffs_free_buffer(io_data);
1138         return ret;
1139 }
1140
1141 static int
1142 ffs_epfile_open(struct inode *inode, struct file *file)
1143 {
1144         struct ffs_epfile *epfile = inode->i_private;
1145
1146         ENTER();
1147
1148         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1149                 return -ENODEV;
1150
1151         file->private_data = epfile;
1152         ffs_data_opened(epfile->ffs);
1153
1154         return 0;
1155 }
1156
1157 static int ffs_aio_cancel(struct kiocb *kiocb)
1158 {
1159         struct ffs_io_data *io_data = kiocb->private;
1160         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1161         int value;
1162
1163         ENTER();
1164
1165         spin_lock_irq(&epfile->ffs->eps_lock);
1166
1167         if (likely(io_data && io_data->ep && io_data->req))
1168                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1169         else
1170                 value = -EINVAL;
1171
1172         spin_unlock_irq(&epfile->ffs->eps_lock);
1173
1174         return value;
1175 }
1176
1177 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1178 {
1179         struct ffs_io_data io_data, *p = &io_data;
1180         ssize_t res;
1181
1182         ENTER();
1183
1184         if (!is_sync_kiocb(kiocb)) {
1185                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1186                 if (unlikely(!p))
1187                         return -ENOMEM;
1188                 p->aio = true;
1189         } else {
1190                 p->aio = false;
1191         }
1192
1193         p->read = false;
1194         p->kiocb = kiocb;
1195         p->data = *from;
1196         p->mm = current->mm;
1197
1198         kiocb->private = p;
1199
1200         if (p->aio)
1201                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1202
1203         res = ffs_epfile_io(kiocb->ki_filp, p);
1204         if (res == -EIOCBQUEUED)
1205                 return res;
1206         if (p->aio)
1207                 kfree(p);
1208         else
1209                 *from = p->data;
1210         return res;
1211 }
1212
1213 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1214 {
1215         struct ffs_io_data io_data, *p = &io_data;
1216         ssize_t res;
1217
1218         ENTER();
1219
1220         if (!is_sync_kiocb(kiocb)) {
1221                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1222                 if (unlikely(!p))
1223                         return -ENOMEM;
1224                 p->aio = true;
1225         } else {
1226                 p->aio = false;
1227         }
1228
1229         p->read = true;
1230         p->kiocb = kiocb;
1231         if (p->aio) {
1232                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1233                 if (!p->to_free) {
1234                         kfree(p);
1235                         return -ENOMEM;
1236                 }
1237         } else {
1238                 p->data = *to;
1239                 p->to_free = NULL;
1240         }
1241         p->mm = current->mm;
1242
1243         kiocb->private = p;
1244
1245         if (p->aio)
1246                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1247
1248         res = ffs_epfile_io(kiocb->ki_filp, p);
1249         if (res == -EIOCBQUEUED)
1250                 return res;
1251
1252         if (p->aio) {
1253                 kfree(p->to_free);
1254                 kfree(p);
1255         } else {
1256                 *to = p->data;
1257         }
1258         return res;
1259 }
1260
1261 static int
1262 ffs_epfile_release(struct inode *inode, struct file *file)
1263 {
1264         struct ffs_epfile *epfile = inode->i_private;
1265
1266         ENTER();
1267
1268         __ffs_epfile_read_buffer_free(epfile);
1269         ffs_data_closed(epfile->ffs);
1270
1271         return 0;
1272 }
1273
1274 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1275                              unsigned long value)
1276 {
1277         struct ffs_epfile *epfile = file->private_data;
1278         struct ffs_ep *ep;
1279         int ret;
1280
1281         ENTER();
1282
1283         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1284                 return -ENODEV;
1285
1286         /* Wait for endpoint to be enabled */
1287         ep = epfile->ep;
1288         if (!ep) {
1289                 if (file->f_flags & O_NONBLOCK)
1290                         return -EAGAIN;
1291
1292                 ret = wait_event_interruptible(
1293                                 epfile->ffs->wait, (ep = epfile->ep));
1294                 if (ret)
1295                         return -EINTR;
1296         }
1297
1298         spin_lock_irq(&epfile->ffs->eps_lock);
1299
1300         /* In the meantime, endpoint got disabled or changed. */
1301         if (epfile->ep != ep) {
1302                 spin_unlock_irq(&epfile->ffs->eps_lock);
1303                 return -ESHUTDOWN;
1304         }
1305
1306         switch (code) {
1307         case FUNCTIONFS_FIFO_STATUS:
1308                 ret = usb_ep_fifo_status(epfile->ep->ep);
1309                 break;
1310         case FUNCTIONFS_FIFO_FLUSH:
1311                 usb_ep_fifo_flush(epfile->ep->ep);
1312                 ret = 0;
1313                 break;
1314         case FUNCTIONFS_CLEAR_HALT:
1315                 ret = usb_ep_clear_halt(epfile->ep->ep);
1316                 break;
1317         case FUNCTIONFS_ENDPOINT_REVMAP:
1318                 ret = epfile->ep->num;
1319                 break;
1320         case FUNCTIONFS_ENDPOINT_DESC:
1321         {
1322                 int desc_idx;
1323                 struct usb_endpoint_descriptor *desc;
1324
1325                 switch (epfile->ffs->gadget->speed) {
1326                 case USB_SPEED_SUPER:
1327                         desc_idx = 2;
1328                         break;
1329                 case USB_SPEED_HIGH:
1330                         desc_idx = 1;
1331                         break;
1332                 default:
1333                         desc_idx = 0;
1334                 }
1335                 desc = epfile->ep->descs[desc_idx];
1336
1337                 spin_unlock_irq(&epfile->ffs->eps_lock);
1338                 ret = copy_to_user((void __user *)value, desc, desc->bLength);
1339                 if (ret)
1340                         ret = -EFAULT;
1341                 return ret;
1342         }
1343         default:
1344                 ret = -ENOTTY;
1345         }
1346         spin_unlock_irq(&epfile->ffs->eps_lock);
1347
1348         return ret;
1349 }
1350
1351 #ifdef CONFIG_COMPAT
1352 static long ffs_epfile_compat_ioctl(struct file *file, unsigned code,
1353                 unsigned long value)
1354 {
1355         return ffs_epfile_ioctl(file, code, value);
1356 }
1357 #endif
1358
1359 static const struct file_operations ffs_epfile_operations = {
1360         .llseek =       no_llseek,
1361
1362         .open =         ffs_epfile_open,
1363         .write_iter =   ffs_epfile_write_iter,
1364         .read_iter =    ffs_epfile_read_iter,
1365         .release =      ffs_epfile_release,
1366         .unlocked_ioctl =       ffs_epfile_ioctl,
1367 #ifdef CONFIG_COMPAT
1368         .compat_ioctl = ffs_epfile_compat_ioctl,
1369 #endif
1370 };
1371
1372
1373 /* File system and super block operations ***********************************/
1374
1375 /*
1376  * Mounting the file system creates a controller file, used first for
1377  * function configuration then later for event monitoring.
1378  */
1379
1380 static struct inode *__must_check
1381 ffs_sb_make_inode(struct super_block *sb, void *data,
1382                   const struct file_operations *fops,
1383                   const struct inode_operations *iops,
1384                   struct ffs_file_perms *perms)
1385 {
1386         struct inode *inode;
1387
1388         ENTER();
1389
1390         inode = new_inode(sb);
1391
1392         if (likely(inode)) {
1393                 struct timespec64 ts = current_time(inode);
1394
1395                 inode->i_ino     = get_next_ino();
1396                 inode->i_mode    = perms->mode;
1397                 inode->i_uid     = perms->uid;
1398                 inode->i_gid     = perms->gid;
1399                 inode->i_atime   = ts;
1400                 inode->i_mtime   = ts;
1401                 inode->i_ctime   = ts;
1402                 inode->i_private = data;
1403                 if (fops)
1404                         inode->i_fop = fops;
1405                 if (iops)
1406                         inode->i_op  = iops;
1407         }
1408
1409         return inode;
1410 }
1411
1412 /* Create "regular" file */
1413 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1414                                         const char *name, void *data,
1415                                         const struct file_operations *fops)
1416 {
1417         struct ffs_data *ffs = sb->s_fs_info;
1418         struct dentry   *dentry;
1419         struct inode    *inode;
1420
1421         ENTER();
1422
1423         dentry = d_alloc_name(sb->s_root, name);
1424         if (unlikely(!dentry))
1425                 return NULL;
1426
1427         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1428         if (unlikely(!inode)) {
1429                 dput(dentry);
1430                 return NULL;
1431         }
1432
1433         d_add(dentry, inode);
1434         return dentry;
1435 }
1436
1437 /* Super block */
1438 static const struct super_operations ffs_sb_operations = {
1439         .statfs =       simple_statfs,
1440         .drop_inode =   generic_delete_inode,
1441 };
1442
1443 struct ffs_sb_fill_data {
1444         struct ffs_file_perms perms;
1445         umode_t root_mode;
1446         const char *dev_name;
1447         bool no_disconnect;
1448         struct ffs_data *ffs_data;
1449 };
1450
1451 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1452 {
1453         struct ffs_sb_fill_data *data = _data;
1454         struct inode    *inode;
1455         struct ffs_data *ffs = data->ffs_data;
1456
1457         ENTER();
1458
1459         ffs->sb              = sb;
1460         data->ffs_data       = NULL;
1461         sb->s_fs_info        = ffs;
1462         sb->s_blocksize      = PAGE_SIZE;
1463         sb->s_blocksize_bits = PAGE_SHIFT;
1464         sb->s_magic          = FUNCTIONFS_MAGIC;
1465         sb->s_op             = &ffs_sb_operations;
1466         sb->s_time_gran      = 1;
1467
1468         /* Root inode */
1469         data->perms.mode = data->root_mode;
1470         inode = ffs_sb_make_inode(sb, NULL,
1471                                   &simple_dir_operations,
1472                                   &simple_dir_inode_operations,
1473                                   &data->perms);
1474         sb->s_root = d_make_root(inode);
1475         if (unlikely(!sb->s_root))
1476                 return -ENOMEM;
1477
1478         /* EP0 file */
1479         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1480                                          &ffs_ep0_operations)))
1481                 return -ENOMEM;
1482
1483         return 0;
1484 }
1485
1486 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1487 {
1488         ENTER();
1489
1490         if (!opts || !*opts)
1491                 return 0;
1492
1493         for (;;) {
1494                 unsigned long value;
1495                 char *eq, *comma;
1496
1497                 /* Option limit */
1498                 comma = strchr(opts, ',');
1499                 if (comma)
1500                         *comma = 0;
1501
1502                 /* Value limit */
1503                 eq = strchr(opts, '=');
1504                 if (unlikely(!eq)) {
1505                         pr_err("'=' missing in %s\n", opts);
1506                         return -EINVAL;
1507                 }
1508                 *eq = 0;
1509
1510                 /* Parse value */
1511                 if (kstrtoul(eq + 1, 0, &value)) {
1512                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1513                         return -EINVAL;
1514                 }
1515
1516                 /* Interpret option */
1517                 switch (eq - opts) {
1518                 case 13:
1519                         if (!memcmp(opts, "no_disconnect", 13))
1520                                 data->no_disconnect = !!value;
1521                         else
1522                                 goto invalid;
1523                         break;
1524                 case 5:
1525                         if (!memcmp(opts, "rmode", 5))
1526                                 data->root_mode  = (value & 0555) | S_IFDIR;
1527                         else if (!memcmp(opts, "fmode", 5))
1528                                 data->perms.mode = (value & 0666) | S_IFREG;
1529                         else
1530                                 goto invalid;
1531                         break;
1532
1533                 case 4:
1534                         if (!memcmp(opts, "mode", 4)) {
1535                                 data->root_mode  = (value & 0555) | S_IFDIR;
1536                                 data->perms.mode = (value & 0666) | S_IFREG;
1537                         } else {
1538                                 goto invalid;
1539                         }
1540                         break;
1541
1542                 case 3:
1543                         if (!memcmp(opts, "uid", 3)) {
1544                                 data->perms.uid = make_kuid(current_user_ns(), value);
1545                                 if (!uid_valid(data->perms.uid)) {
1546                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1547                                         return -EINVAL;
1548                                 }
1549                         } else if (!memcmp(opts, "gid", 3)) {
1550                                 data->perms.gid = make_kgid(current_user_ns(), value);
1551                                 if (!gid_valid(data->perms.gid)) {
1552                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1553                                         return -EINVAL;
1554                                 }
1555                         } else {
1556                                 goto invalid;
1557                         }
1558                         break;
1559
1560                 default:
1561 invalid:
1562                         pr_err("%s: invalid option\n", opts);
1563                         return -EINVAL;
1564                 }
1565
1566                 /* Next iteration */
1567                 if (!comma)
1568                         break;
1569                 opts = comma + 1;
1570         }
1571
1572         return 0;
1573 }
1574
1575 /* "mount -t functionfs dev_name /dev/function" ends up here */
1576
1577 static struct dentry *
1578 ffs_fs_mount(struct file_system_type *t, int flags,
1579               const char *dev_name, void *opts)
1580 {
1581         struct ffs_sb_fill_data data = {
1582                 .perms = {
1583                         .mode = S_IFREG | 0600,
1584                         .uid = GLOBAL_ROOT_UID,
1585                         .gid = GLOBAL_ROOT_GID,
1586                 },
1587                 .root_mode = S_IFDIR | 0500,
1588                 .no_disconnect = false,
1589         };
1590         struct dentry *rv;
1591         int ret;
1592         void *ffs_dev;
1593         struct ffs_data *ffs;
1594
1595         ENTER();
1596
1597         ret = ffs_fs_parse_opts(&data, opts);
1598         if (unlikely(ret < 0))
1599                 return ERR_PTR(ret);
1600
1601         ffs = ffs_data_new(dev_name);
1602         if (unlikely(!ffs))
1603                 return ERR_PTR(-ENOMEM);
1604         ffs->file_perms = data.perms;
1605         ffs->no_disconnect = data.no_disconnect;
1606
1607         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1608         if (unlikely(!ffs->dev_name)) {
1609                 ffs_data_put(ffs);
1610                 return ERR_PTR(-ENOMEM);
1611         }
1612
1613         ffs_dev = ffs_acquire_dev(dev_name);
1614         if (IS_ERR(ffs_dev)) {
1615                 ffs_data_put(ffs);
1616                 return ERR_CAST(ffs_dev);
1617         }
1618         ffs->private_data = ffs_dev;
1619         data.ffs_data = ffs;
1620
1621         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1622         if (IS_ERR(rv) && data.ffs_data) {
1623                 ffs_release_dev(data.ffs_data);
1624                 ffs_data_put(data.ffs_data);
1625         }
1626         return rv;
1627 }
1628
1629 static void
1630 ffs_fs_kill_sb(struct super_block *sb)
1631 {
1632         ENTER();
1633
1634         kill_litter_super(sb);
1635         if (sb->s_fs_info) {
1636                 ffs_release_dev(sb->s_fs_info);
1637                 ffs_data_closed(sb->s_fs_info);
1638         }
1639 }
1640
1641 static struct file_system_type ffs_fs_type = {
1642         .owner          = THIS_MODULE,
1643         .name           = "functionfs",
1644         .mount          = ffs_fs_mount,
1645         .kill_sb        = ffs_fs_kill_sb,
1646 };
1647 MODULE_ALIAS_FS("functionfs");
1648
1649
1650 /* Driver's main init/cleanup functions *************************************/
1651
1652 static int functionfs_init(void)
1653 {
1654         int ret;
1655
1656         ENTER();
1657
1658         ret = register_filesystem(&ffs_fs_type);
1659         if (likely(!ret))
1660                 pr_info("file system registered\n");
1661         else
1662                 pr_err("failed registering file system (%d)\n", ret);
1663
1664         return ret;
1665 }
1666
1667 static void functionfs_cleanup(void)
1668 {
1669         ENTER();
1670
1671         pr_info("unloading\n");
1672         unregister_filesystem(&ffs_fs_type);
1673 }
1674
1675
1676 /* ffs_data and ffs_function construction and destruction code **************/
1677
1678 static void ffs_data_clear(struct ffs_data *ffs);
1679 static void ffs_data_reset(struct ffs_data *ffs);
1680
1681 static void ffs_data_get(struct ffs_data *ffs)
1682 {
1683         ENTER();
1684
1685         refcount_inc(&ffs->ref);
1686 }
1687
1688 static void ffs_data_opened(struct ffs_data *ffs)
1689 {
1690         ENTER();
1691
1692         refcount_inc(&ffs->ref);
1693         if (atomic_add_return(1, &ffs->opened) == 1 &&
1694                         ffs->state == FFS_DEACTIVATED) {
1695                 ffs->state = FFS_CLOSING;
1696                 ffs_data_reset(ffs);
1697         }
1698 }
1699
1700 static void ffs_data_put(struct ffs_data *ffs)
1701 {
1702         ENTER();
1703
1704         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1705                 pr_info("%s(): freeing\n", __func__);
1706                 ffs_data_clear(ffs);
1707                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1708                        waitqueue_active(&ffs->ep0req_completion.wait) ||
1709                        waitqueue_active(&ffs->wait));
1710                 destroy_workqueue(ffs->io_completion_wq);
1711                 kfree(ffs->dev_name);
1712                 kfree(ffs);
1713         }
1714 }
1715
1716 static void ffs_data_closed(struct ffs_data *ffs)
1717 {
1718         ENTER();
1719
1720         if (atomic_dec_and_test(&ffs->opened)) {
1721                 if (ffs->no_disconnect) {
1722                         ffs->state = FFS_DEACTIVATED;
1723                         if (ffs->epfiles) {
1724                                 ffs_epfiles_destroy(ffs->epfiles,
1725                                                    ffs->eps_count);
1726                                 ffs->epfiles = NULL;
1727                         }
1728                         if (ffs->setup_state == FFS_SETUP_PENDING)
1729                                 __ffs_ep0_stall(ffs);
1730                 } else {
1731                         ffs->state = FFS_CLOSING;
1732                         ffs_data_reset(ffs);
1733                 }
1734         }
1735         if (atomic_read(&ffs->opened) < 0) {
1736                 ffs->state = FFS_CLOSING;
1737                 ffs_data_reset(ffs);
1738         }
1739
1740         ffs_data_put(ffs);
1741 }
1742
1743 static struct ffs_data *ffs_data_new(const char *dev_name)
1744 {
1745         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1746         if (unlikely(!ffs))
1747                 return NULL;
1748
1749         ENTER();
1750
1751         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1752         if (!ffs->io_completion_wq) {
1753                 kfree(ffs);
1754                 return NULL;
1755         }
1756
1757         refcount_set(&ffs->ref, 1);
1758         atomic_set(&ffs->opened, 0);
1759         ffs->state = FFS_READ_DESCRIPTORS;
1760         mutex_init(&ffs->mutex);
1761         spin_lock_init(&ffs->eps_lock);
1762         init_waitqueue_head(&ffs->ev.waitq);
1763         init_waitqueue_head(&ffs->wait);
1764         init_completion(&ffs->ep0req_completion);
1765
1766         /* XXX REVISIT need to update it in some places, or do we? */
1767         ffs->ev.can_stall = 1;
1768
1769         return ffs;
1770 }
1771
1772 static void ffs_data_clear(struct ffs_data *ffs)
1773 {
1774         ENTER();
1775
1776         ffs_closed(ffs);
1777
1778         BUG_ON(ffs->gadget);
1779
1780         if (ffs->epfiles)
1781                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1782
1783         if (ffs->ffs_eventfd)
1784                 eventfd_ctx_put(ffs->ffs_eventfd);
1785
1786         kfree(ffs->raw_descs_data);
1787         kfree(ffs->raw_strings);
1788         kfree(ffs->stringtabs);
1789 }
1790
1791 static void ffs_data_reset(struct ffs_data *ffs)
1792 {
1793         ENTER();
1794
1795         ffs_data_clear(ffs);
1796
1797         ffs->epfiles = NULL;
1798         ffs->raw_descs_data = NULL;
1799         ffs->raw_descs = NULL;
1800         ffs->raw_strings = NULL;
1801         ffs->stringtabs = NULL;
1802
1803         ffs->raw_descs_length = 0;
1804         ffs->fs_descs_count = 0;
1805         ffs->hs_descs_count = 0;
1806         ffs->ss_descs_count = 0;
1807
1808         ffs->strings_count = 0;
1809         ffs->interfaces_count = 0;
1810         ffs->eps_count = 0;
1811
1812         ffs->ev.count = 0;
1813
1814         ffs->state = FFS_READ_DESCRIPTORS;
1815         ffs->setup_state = FFS_NO_SETUP;
1816         ffs->flags = 0;
1817 }
1818
1819
1820 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1821 {
1822         struct usb_gadget_strings **lang;
1823         int first_id;
1824
1825         ENTER();
1826
1827         if (WARN_ON(ffs->state != FFS_ACTIVE
1828                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1829                 return -EBADFD;
1830
1831         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1832         if (unlikely(first_id < 0))
1833                 return first_id;
1834
1835         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1836         if (unlikely(!ffs->ep0req))
1837                 return -ENOMEM;
1838         ffs->ep0req->complete = ffs_ep0_complete;
1839         ffs->ep0req->context = ffs;
1840
1841         lang = ffs->stringtabs;
1842         if (lang) {
1843                 for (; *lang; ++lang) {
1844                         struct usb_string *str = (*lang)->strings;
1845                         int id = first_id;
1846                         for (; str->s; ++id, ++str)
1847                                 str->id = id;
1848                 }
1849         }
1850
1851         ffs->gadget = cdev->gadget;
1852         ffs_data_get(ffs);
1853         return 0;
1854 }
1855
1856 static void functionfs_unbind(struct ffs_data *ffs)
1857 {
1858         ENTER();
1859
1860         if (!WARN_ON(!ffs->gadget)) {
1861                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1862                 ffs->ep0req = NULL;
1863                 ffs->gadget = NULL;
1864                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1865                 ffs_data_put(ffs);
1866         }
1867 }
1868
1869 static int ffs_epfiles_create(struct ffs_data *ffs)
1870 {
1871         struct ffs_epfile *epfile, *epfiles;
1872         unsigned i, count;
1873
1874         ENTER();
1875
1876         count = ffs->eps_count;
1877         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1878         if (!epfiles)
1879                 return -ENOMEM;
1880
1881         epfile = epfiles;
1882         for (i = 1; i <= count; ++i, ++epfile) {
1883                 epfile->ffs = ffs;
1884                 mutex_init(&epfile->mutex);
1885                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1886                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1887                 else
1888                         sprintf(epfile->name, "ep%u", i);
1889                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1890                                                  epfile,
1891                                                  &ffs_epfile_operations);
1892                 if (unlikely(!epfile->dentry)) {
1893                         ffs_epfiles_destroy(epfiles, i - 1);
1894                         return -ENOMEM;
1895                 }
1896         }
1897
1898         ffs->epfiles = epfiles;
1899         return 0;
1900 }
1901
1902 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1903 {
1904         struct ffs_epfile *epfile = epfiles;
1905
1906         ENTER();
1907
1908         for (; count; --count, ++epfile) {
1909                 BUG_ON(mutex_is_locked(&epfile->mutex));
1910                 if (epfile->dentry) {
1911                         d_delete(epfile->dentry);
1912                         dput(epfile->dentry);
1913                         epfile->dentry = NULL;
1914                 }
1915         }
1916
1917         kfree(epfiles);
1918 }
1919
1920 static void ffs_func_eps_disable(struct ffs_function *func)
1921 {
1922         struct ffs_ep *ep         = func->eps;
1923         struct ffs_epfile *epfile = func->ffs->epfiles;
1924         unsigned count            = func->ffs->eps_count;
1925         unsigned long flags;
1926
1927         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1928         while (count--) {
1929                 /* pending requests get nuked */
1930                 if (likely(ep->ep))
1931                         usb_ep_disable(ep->ep);
1932                 ++ep;
1933
1934                 if (epfile) {
1935                         epfile->ep = NULL;
1936                         __ffs_epfile_read_buffer_free(epfile);
1937                         ++epfile;
1938                 }
1939         }
1940         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1941 }
1942
1943 static int ffs_func_eps_enable(struct ffs_function *func)
1944 {
1945         struct ffs_data *ffs      = func->ffs;
1946         struct ffs_ep *ep         = func->eps;
1947         struct ffs_epfile *epfile = ffs->epfiles;
1948         unsigned count            = ffs->eps_count;
1949         unsigned long flags;
1950         int ret = 0;
1951
1952         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1953         while(count--) {
1954                 ep->ep->driver_data = ep;
1955
1956                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1957                 if (ret) {
1958                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1959                                         __func__, ep->ep->name, ret);
1960                         break;
1961                 }
1962
1963                 ret = usb_ep_enable(ep->ep);
1964                 if (likely(!ret)) {
1965                         epfile->ep = ep;
1966                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1967                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1968                 } else {
1969                         break;
1970                 }
1971
1972                 ++ep;
1973                 ++epfile;
1974         }
1975
1976         wake_up_interruptible(&ffs->wait);
1977         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1978
1979         return ret;
1980 }
1981
1982
1983 /* Parsing and building descriptors and strings *****************************/
1984
1985 /*
1986  * This validates if data pointed by data is a valid USB descriptor as
1987  * well as record how many interfaces, endpoints and strings are
1988  * required by given configuration.  Returns address after the
1989  * descriptor or NULL if data is invalid.
1990  */
1991
1992 enum ffs_entity_type {
1993         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1994 };
1995
1996 enum ffs_os_desc_type {
1997         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1998 };
1999
2000 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2001                                    u8 *valuep,
2002                                    struct usb_descriptor_header *desc,
2003                                    void *priv);
2004
2005 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2006                                     struct usb_os_desc_header *h, void *data,
2007                                     unsigned len, void *priv);
2008
2009 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2010                                            ffs_entity_callback entity,
2011                                            void *priv, int *current_class)
2012 {
2013         struct usb_descriptor_header *_ds = (void *)data;
2014         u8 length;
2015         int ret;
2016
2017         ENTER();
2018
2019         /* At least two bytes are required: length and type */
2020         if (len < 2) {
2021                 pr_vdebug("descriptor too short\n");
2022                 return -EINVAL;
2023         }
2024
2025         /* If we have at least as many bytes as the descriptor takes? */
2026         length = _ds->bLength;
2027         if (len < length) {
2028                 pr_vdebug("descriptor longer then available data\n");
2029                 return -EINVAL;
2030         }
2031
2032 #define __entity_check_INTERFACE(val)  1
2033 #define __entity_check_STRING(val)     (val)
2034 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2035 #define __entity(type, val) do {                                        \
2036                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2037                 if (unlikely(!__entity_check_ ##type(val))) {           \
2038                         pr_vdebug("invalid entity's value\n");          \
2039                         return -EINVAL;                                 \
2040                 }                                                       \
2041                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2042                 if (unlikely(ret < 0)) {                                \
2043                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2044                                  (val), ret);                           \
2045                         return ret;                                     \
2046                 }                                                       \
2047         } while (0)
2048
2049         /* Parse descriptor depending on type. */
2050         switch (_ds->bDescriptorType) {
2051         case USB_DT_DEVICE:
2052         case USB_DT_CONFIG:
2053         case USB_DT_STRING:
2054         case USB_DT_DEVICE_QUALIFIER:
2055                 /* function can't have any of those */
2056                 pr_vdebug("descriptor reserved for gadget: %d\n",
2057                       _ds->bDescriptorType);
2058                 return -EINVAL;
2059
2060         case USB_DT_INTERFACE: {
2061                 struct usb_interface_descriptor *ds = (void *)_ds;
2062                 pr_vdebug("interface descriptor\n");
2063                 if (length != sizeof *ds)
2064                         goto inv_length;
2065
2066                 __entity(INTERFACE, ds->bInterfaceNumber);
2067                 if (ds->iInterface)
2068                         __entity(STRING, ds->iInterface);
2069                 *current_class = ds->bInterfaceClass;
2070         }
2071                 break;
2072
2073         case USB_DT_ENDPOINT: {
2074                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2075                 pr_vdebug("endpoint descriptor\n");
2076                 if (length != USB_DT_ENDPOINT_SIZE &&
2077                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2078                         goto inv_length;
2079                 __entity(ENDPOINT, ds->bEndpointAddress);
2080         }
2081                 break;
2082
2083         case USB_TYPE_CLASS | 0x01:
2084                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2085                         pr_vdebug("hid descriptor\n");
2086                         if (length != sizeof(struct hid_descriptor))
2087                                 goto inv_length;
2088                         break;
2089                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2090                         pr_vdebug("ccid descriptor\n");
2091                         if (length != sizeof(struct ccid_descriptor))
2092                                 goto inv_length;
2093                         break;
2094                 } else {
2095                         pr_vdebug("unknown descriptor: %d for class %d\n",
2096                               _ds->bDescriptorType, *current_class);
2097                         return -EINVAL;
2098                 }
2099
2100         case USB_DT_OTG:
2101                 if (length != sizeof(struct usb_otg_descriptor))
2102                         goto inv_length;
2103                 break;
2104
2105         case USB_DT_INTERFACE_ASSOCIATION: {
2106                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2107                 pr_vdebug("interface association descriptor\n");
2108                 if (length != sizeof *ds)
2109                         goto inv_length;
2110                 if (ds->iFunction)
2111                         __entity(STRING, ds->iFunction);
2112         }
2113                 break;
2114
2115         case USB_DT_SS_ENDPOINT_COMP:
2116                 pr_vdebug("EP SS companion descriptor\n");
2117                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2118                         goto inv_length;
2119                 break;
2120
2121         case USB_DT_OTHER_SPEED_CONFIG:
2122         case USB_DT_INTERFACE_POWER:
2123         case USB_DT_DEBUG:
2124         case USB_DT_SECURITY:
2125         case USB_DT_CS_RADIO_CONTROL:
2126                 /* TODO */
2127                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2128                 return -EINVAL;
2129
2130         default:
2131                 /* We should never be here */
2132                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2133                 return -EINVAL;
2134
2135 inv_length:
2136                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2137                           _ds->bLength, _ds->bDescriptorType);
2138                 return -EINVAL;
2139         }
2140
2141 #undef __entity
2142 #undef __entity_check_DESCRIPTOR
2143 #undef __entity_check_INTERFACE
2144 #undef __entity_check_STRING
2145 #undef __entity_check_ENDPOINT
2146
2147         return length;
2148 }
2149
2150 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2151                                      ffs_entity_callback entity, void *priv)
2152 {
2153         const unsigned _len = len;
2154         unsigned long num = 0;
2155         int current_class = -1;
2156
2157         ENTER();
2158
2159         for (;;) {
2160                 int ret;
2161
2162                 if (num == count)
2163                         data = NULL;
2164
2165                 /* Record "descriptor" entity */
2166                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2167                 if (unlikely(ret < 0)) {
2168                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2169                                  num, ret);
2170                         return ret;
2171                 }
2172
2173                 if (!data)
2174                         return _len - len;
2175
2176                 ret = ffs_do_single_desc(data, len, entity, priv,
2177                         &current_class);
2178                 if (unlikely(ret < 0)) {
2179                         pr_debug("%s returns %d\n", __func__, ret);
2180                         return ret;
2181                 }
2182
2183                 len -= ret;
2184                 data += ret;
2185                 ++num;
2186         }
2187 }
2188
2189 static int __ffs_data_do_entity(enum ffs_entity_type type,
2190                                 u8 *valuep, struct usb_descriptor_header *desc,
2191                                 void *priv)
2192 {
2193         struct ffs_desc_helper *helper = priv;
2194         struct usb_endpoint_descriptor *d;
2195
2196         ENTER();
2197
2198         switch (type) {
2199         case FFS_DESCRIPTOR:
2200                 break;
2201
2202         case FFS_INTERFACE:
2203                 /*
2204                  * Interfaces are indexed from zero so if we
2205                  * encountered interface "n" then there are at least
2206                  * "n+1" interfaces.
2207                  */
2208                 if (*valuep >= helper->interfaces_count)
2209                         helper->interfaces_count = *valuep + 1;
2210                 break;
2211
2212         case FFS_STRING:
2213                 /*
2214                  * Strings are indexed from 1 (0 is reserved
2215                  * for languages list)
2216                  */
2217                 if (*valuep > helper->ffs->strings_count)
2218                         helper->ffs->strings_count = *valuep;
2219                 break;
2220
2221         case FFS_ENDPOINT:
2222                 d = (void *)desc;
2223                 helper->eps_count++;
2224                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2225                         return -EINVAL;
2226                 /* Check if descriptors for any speed were already parsed */
2227                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2228                         helper->ffs->eps_addrmap[helper->eps_count] =
2229                                 d->bEndpointAddress;
2230                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2231                                 d->bEndpointAddress)
2232                         return -EINVAL;
2233                 break;
2234         }
2235
2236         return 0;
2237 }
2238
2239 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2240                                    struct usb_os_desc_header *desc)
2241 {
2242         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2243         u16 w_index = le16_to_cpu(desc->wIndex);
2244
2245         if (bcd_version != 1) {
2246                 pr_vdebug("unsupported os descriptors version: %d",
2247                           bcd_version);
2248                 return -EINVAL;
2249         }
2250         switch (w_index) {
2251         case 0x4:
2252                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2253                 break;
2254         case 0x5:
2255                 *next_type = FFS_OS_DESC_EXT_PROP;
2256                 break;
2257         default:
2258                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2259                 return -EINVAL;
2260         }
2261
2262         return sizeof(*desc);
2263 }
2264
2265 /*
2266  * Process all extended compatibility/extended property descriptors
2267  * of a feature descriptor
2268  */
2269 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2270                                               enum ffs_os_desc_type type,
2271                                               u16 feature_count,
2272                                               ffs_os_desc_callback entity,
2273                                               void *priv,
2274                                               struct usb_os_desc_header *h)
2275 {
2276         int ret;
2277         const unsigned _len = len;
2278
2279         ENTER();
2280
2281         /* loop over all ext compat/ext prop descriptors */
2282         while (feature_count--) {
2283                 ret = entity(type, h, data, len, priv);
2284                 if (unlikely(ret < 0)) {
2285                         pr_debug("bad OS descriptor, type: %d\n", type);
2286                         return ret;
2287                 }
2288                 data += ret;
2289                 len -= ret;
2290         }
2291         return _len - len;
2292 }
2293
2294 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2295 static int __must_check ffs_do_os_descs(unsigned count,
2296                                         char *data, unsigned len,
2297                                         ffs_os_desc_callback entity, void *priv)
2298 {
2299         const unsigned _len = len;
2300         unsigned long num = 0;
2301
2302         ENTER();
2303
2304         for (num = 0; num < count; ++num) {
2305                 int ret;
2306                 enum ffs_os_desc_type type;
2307                 u16 feature_count;
2308                 struct usb_os_desc_header *desc = (void *)data;
2309
2310                 if (len < sizeof(*desc))
2311                         return -EINVAL;
2312
2313                 /*
2314                  * Record "descriptor" entity.
2315                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2316                  * Move the data pointer to the beginning of extended
2317                  * compatibilities proper or extended properties proper
2318                  * portions of the data
2319                  */
2320                 if (le32_to_cpu(desc->dwLength) > len)
2321                         return -EINVAL;
2322
2323                 ret = __ffs_do_os_desc_header(&type, desc);
2324                 if (unlikely(ret < 0)) {
2325                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2326                                  num, ret);
2327                         return ret;
2328                 }
2329                 /*
2330                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2331                  */
2332                 feature_count = le16_to_cpu(desc->wCount);
2333                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2334                     (feature_count > 255 || desc->Reserved))
2335                                 return -EINVAL;
2336                 len -= ret;
2337                 data += ret;
2338
2339                 /*
2340                  * Process all function/property descriptors
2341                  * of this Feature Descriptor
2342                  */
2343                 ret = ffs_do_single_os_desc(data, len, type,
2344                                             feature_count, entity, priv, desc);
2345                 if (unlikely(ret < 0)) {
2346                         pr_debug("%s returns %d\n", __func__, ret);
2347                         return ret;
2348                 }
2349
2350                 len -= ret;
2351                 data += ret;
2352         }
2353         return _len - len;
2354 }
2355
2356 /**
2357  * Validate contents of the buffer from userspace related to OS descriptors.
2358  */
2359 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2360                                  struct usb_os_desc_header *h, void *data,
2361                                  unsigned len, void *priv)
2362 {
2363         struct ffs_data *ffs = priv;
2364         u8 length;
2365
2366         ENTER();
2367
2368         switch (type) {
2369         case FFS_OS_DESC_EXT_COMPAT: {
2370                 struct usb_ext_compat_desc *d = data;
2371                 int i;
2372
2373                 if (len < sizeof(*d) ||
2374                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2375                         return -EINVAL;
2376                 if (d->Reserved1 != 1) {
2377                         /*
2378                          * According to the spec, Reserved1 must be set to 1
2379                          * but older kernels incorrectly rejected non-zero
2380                          * values.  We fix it here to avoid returning EINVAL
2381                          * in response to values we used to accept.
2382                          */
2383                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2384                         d->Reserved1 = 1;
2385                 }
2386                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2387                         if (d->Reserved2[i])
2388                                 return -EINVAL;
2389
2390                 length = sizeof(struct usb_ext_compat_desc);
2391         }
2392                 break;
2393         case FFS_OS_DESC_EXT_PROP: {
2394                 struct usb_ext_prop_desc *d = data;
2395                 u32 type, pdl;
2396                 u16 pnl;
2397
2398                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2399                         return -EINVAL;
2400                 length = le32_to_cpu(d->dwSize);
2401                 if (len < length)
2402                         return -EINVAL;
2403                 type = le32_to_cpu(d->dwPropertyDataType);
2404                 if (type < USB_EXT_PROP_UNICODE ||
2405                     type > USB_EXT_PROP_UNICODE_MULTI) {
2406                         pr_vdebug("unsupported os descriptor property type: %d",
2407                                   type);
2408                         return -EINVAL;
2409                 }
2410                 pnl = le16_to_cpu(d->wPropertyNameLength);
2411                 if (length < 14 + pnl) {
2412                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2413                                   length, pnl, type);
2414                         return -EINVAL;
2415                 }
2416                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2417                 if (length != 14 + pnl + pdl) {
2418                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2419                                   length, pnl, pdl, type);
2420                         return -EINVAL;
2421                 }
2422                 ++ffs->ms_os_descs_ext_prop_count;
2423                 /* property name reported to the host as "WCHAR"s */
2424                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2425                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2426         }
2427                 break;
2428         default:
2429                 pr_vdebug("unknown descriptor: %d\n", type);
2430                 return -EINVAL;
2431         }
2432         return length;
2433 }
2434
2435 static int __ffs_data_got_descs(struct ffs_data *ffs,
2436                                 char *const _data, size_t len)
2437 {
2438         char *data = _data, *raw_descs;
2439         unsigned os_descs_count = 0, counts[3], flags;
2440         int ret = -EINVAL, i;
2441         struct ffs_desc_helper helper;
2442
2443         ENTER();
2444
2445         if (get_unaligned_le32(data + 4) != len)
2446                 goto error;
2447
2448         switch (get_unaligned_le32(data)) {
2449         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2450                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2451                 data += 8;
2452                 len  -= 8;
2453                 break;
2454         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2455                 flags = get_unaligned_le32(data + 8);
2456                 ffs->user_flags = flags;
2457                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2458                               FUNCTIONFS_HAS_HS_DESC |
2459                               FUNCTIONFS_HAS_SS_DESC |
2460                               FUNCTIONFS_HAS_MS_OS_DESC |
2461                               FUNCTIONFS_VIRTUAL_ADDR |
2462                               FUNCTIONFS_EVENTFD |
2463                               FUNCTIONFS_ALL_CTRL_RECIP |
2464                               FUNCTIONFS_CONFIG0_SETUP)) {
2465                         ret = -ENOSYS;
2466                         goto error;
2467                 }
2468                 data += 12;
2469                 len  -= 12;
2470                 break;
2471         default:
2472                 goto error;
2473         }
2474
2475         if (flags & FUNCTIONFS_EVENTFD) {
2476                 if (len < 4)
2477                         goto error;
2478                 ffs->ffs_eventfd =
2479                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2480                 if (IS_ERR(ffs->ffs_eventfd)) {
2481                         ret = PTR_ERR(ffs->ffs_eventfd);
2482                         ffs->ffs_eventfd = NULL;
2483                         goto error;
2484                 }
2485                 data += 4;
2486                 len  -= 4;
2487         }
2488
2489         /* Read fs_count, hs_count and ss_count (if present) */
2490         for (i = 0; i < 3; ++i) {
2491                 if (!(flags & (1 << i))) {
2492                         counts[i] = 0;
2493                 } else if (len < 4) {
2494                         goto error;
2495                 } else {
2496                         counts[i] = get_unaligned_le32(data);
2497                         data += 4;
2498                         len  -= 4;
2499                 }
2500         }
2501         if (flags & (1 << i)) {
2502                 if (len < 4) {
2503                         goto error;
2504                 }
2505                 os_descs_count = get_unaligned_le32(data);
2506                 data += 4;
2507                 len -= 4;
2508         };
2509
2510         /* Read descriptors */
2511         raw_descs = data;
2512         helper.ffs = ffs;
2513         for (i = 0; i < 3; ++i) {
2514                 if (!counts[i])
2515                         continue;
2516                 helper.interfaces_count = 0;
2517                 helper.eps_count = 0;
2518                 ret = ffs_do_descs(counts[i], data, len,
2519                                    __ffs_data_do_entity, &helper);
2520                 if (ret < 0)
2521                         goto error;
2522                 if (!ffs->eps_count && !ffs->interfaces_count) {
2523                         ffs->eps_count = helper.eps_count;
2524                         ffs->interfaces_count = helper.interfaces_count;
2525                 } else {
2526                         if (ffs->eps_count != helper.eps_count) {
2527                                 ret = -EINVAL;
2528                                 goto error;
2529                         }
2530                         if (ffs->interfaces_count != helper.interfaces_count) {
2531                                 ret = -EINVAL;
2532                                 goto error;
2533                         }
2534                 }
2535                 data += ret;
2536                 len  -= ret;
2537         }
2538         if (os_descs_count) {
2539                 ret = ffs_do_os_descs(os_descs_count, data, len,
2540                                       __ffs_data_do_os_desc, ffs);
2541                 if (ret < 0)
2542                         goto error;
2543                 data += ret;
2544                 len -= ret;
2545         }
2546
2547         if (raw_descs == data || len) {
2548                 ret = -EINVAL;
2549                 goto error;
2550         }
2551
2552         ffs->raw_descs_data     = _data;
2553         ffs->raw_descs          = raw_descs;
2554         ffs->raw_descs_length   = data - raw_descs;
2555         ffs->fs_descs_count     = counts[0];
2556         ffs->hs_descs_count     = counts[1];
2557         ffs->ss_descs_count     = counts[2];
2558         ffs->ms_os_descs_count  = os_descs_count;
2559
2560         return 0;
2561
2562 error:
2563         kfree(_data);
2564         return ret;
2565 }
2566
2567 static int __ffs_data_got_strings(struct ffs_data *ffs,
2568                                   char *const _data, size_t len)
2569 {
2570         u32 str_count, needed_count, lang_count;
2571         struct usb_gadget_strings **stringtabs, *t;
2572         const char *data = _data;
2573         struct usb_string *s;
2574
2575         ENTER();
2576
2577         if (unlikely(len < 16 ||
2578                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2579                      get_unaligned_le32(data + 4) != len))
2580                 goto error;
2581         str_count  = get_unaligned_le32(data + 8);
2582         lang_count = get_unaligned_le32(data + 12);
2583
2584         /* if one is zero the other must be zero */
2585         if (unlikely(!str_count != !lang_count))
2586                 goto error;
2587
2588         /* Do we have at least as many strings as descriptors need? */
2589         needed_count = ffs->strings_count;
2590         if (unlikely(str_count < needed_count))
2591                 goto error;
2592
2593         /*
2594          * If we don't need any strings just return and free all
2595          * memory.
2596          */
2597         if (!needed_count) {
2598                 kfree(_data);
2599                 return 0;
2600         }
2601
2602         /* Allocate everything in one chunk so there's less maintenance. */
2603         {
2604                 unsigned i = 0;
2605                 vla_group(d);
2606                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2607                         lang_count + 1);
2608                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2609                 vla_item(d, struct usb_string, strings,
2610                         lang_count*(needed_count+1));
2611
2612                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2613
2614                 if (unlikely(!vlabuf)) {
2615                         kfree(_data);
2616                         return -ENOMEM;
2617                 }
2618
2619                 /* Initialize the VLA pointers */
2620                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2621                 t = vla_ptr(vlabuf, d, stringtab);
2622                 i = lang_count;
2623                 do {
2624                         *stringtabs++ = t++;
2625                 } while (--i);
2626                 *stringtabs = NULL;
2627
2628                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2629                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2630                 t = vla_ptr(vlabuf, d, stringtab);
2631                 s = vla_ptr(vlabuf, d, strings);
2632         }
2633
2634         /* For each language */
2635         data += 16;
2636         len -= 16;
2637
2638         do { /* lang_count > 0 so we can use do-while */
2639                 unsigned needed = needed_count;
2640
2641                 if (unlikely(len < 3))
2642                         goto error_free;
2643                 t->language = get_unaligned_le16(data);
2644                 t->strings  = s;
2645                 ++t;
2646
2647                 data += 2;
2648                 len -= 2;
2649
2650                 /* For each string */
2651                 do { /* str_count > 0 so we can use do-while */
2652                         size_t length = strnlen(data, len);
2653
2654                         if (unlikely(length == len))
2655                                 goto error_free;
2656
2657                         /*
2658                          * User may provide more strings then we need,
2659                          * if that's the case we simply ignore the
2660                          * rest
2661                          */
2662                         if (likely(needed)) {
2663                                 /*
2664                                  * s->id will be set while adding
2665                                  * function to configuration so for
2666                                  * now just leave garbage here.
2667                                  */
2668                                 s->s = data;
2669                                 --needed;
2670                                 ++s;
2671                         }
2672
2673                         data += length + 1;
2674                         len -= length + 1;
2675                 } while (--str_count);
2676
2677                 s->id = 0;   /* terminator */
2678                 s->s = NULL;
2679                 ++s;
2680
2681         } while (--lang_count);
2682
2683         /* Some garbage left? */
2684         if (unlikely(len))
2685                 goto error_free;
2686
2687         /* Done! */
2688         ffs->stringtabs = stringtabs;
2689         ffs->raw_strings = _data;
2690
2691         return 0;
2692
2693 error_free:
2694         kfree(stringtabs);
2695 error:
2696         kfree(_data);
2697         return -EINVAL;
2698 }
2699
2700
2701 /* Events handling and management *******************************************/
2702
2703 static void __ffs_event_add(struct ffs_data *ffs,
2704                             enum usb_functionfs_event_type type)
2705 {
2706         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2707         int neg = 0;
2708
2709         /*
2710          * Abort any unhandled setup
2711          *
2712          * We do not need to worry about some cmpxchg() changing value
2713          * of ffs->setup_state without holding the lock because when
2714          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2715          * the source does nothing.
2716          */
2717         if (ffs->setup_state == FFS_SETUP_PENDING)
2718                 ffs->setup_state = FFS_SETUP_CANCELLED;
2719
2720         /*
2721          * Logic of this function guarantees that there are at most four pending
2722          * evens on ffs->ev.types queue.  This is important because the queue
2723          * has space for four elements only and __ffs_ep0_read_events function
2724          * depends on that limit as well.  If more event types are added, those
2725          * limits have to be revisited or guaranteed to still hold.
2726          */
2727         switch (type) {
2728         case FUNCTIONFS_RESUME:
2729                 rem_type2 = FUNCTIONFS_SUSPEND;
2730                 /* FALL THROUGH */
2731         case FUNCTIONFS_SUSPEND:
2732         case FUNCTIONFS_SETUP:
2733                 rem_type1 = type;
2734                 /* Discard all similar events */
2735                 break;
2736
2737         case FUNCTIONFS_BIND:
2738         case FUNCTIONFS_UNBIND:
2739         case FUNCTIONFS_DISABLE:
2740         case FUNCTIONFS_ENABLE:
2741                 /* Discard everything other then power management. */
2742                 rem_type1 = FUNCTIONFS_SUSPEND;
2743                 rem_type2 = FUNCTIONFS_RESUME;
2744                 neg = 1;
2745                 break;
2746
2747         default:
2748                 WARN(1, "%d: unknown event, this should not happen\n", type);
2749                 return;
2750         }
2751
2752         {
2753                 u8 *ev  = ffs->ev.types, *out = ev;
2754                 unsigned n = ffs->ev.count;
2755                 for (; n; --n, ++ev)
2756                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2757                                 *out++ = *ev;
2758                         else
2759                                 pr_vdebug("purging event %d\n", *ev);
2760                 ffs->ev.count = out - ffs->ev.types;
2761         }
2762
2763         pr_vdebug("adding event %d\n", type);
2764         ffs->ev.types[ffs->ev.count++] = type;
2765         wake_up_locked(&ffs->ev.waitq);
2766         if (ffs->ffs_eventfd)
2767                 eventfd_signal(ffs->ffs_eventfd, 1);
2768 }
2769
2770 static void ffs_event_add(struct ffs_data *ffs,
2771                           enum usb_functionfs_event_type type)
2772 {
2773         unsigned long flags;
2774         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2775         __ffs_event_add(ffs, type);
2776         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2777 }
2778
2779 /* Bind/unbind USB function hooks *******************************************/
2780
2781 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2782 {
2783         int i;
2784
2785         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2786                 if (ffs->eps_addrmap[i] == endpoint_address)
2787                         return i;
2788         return -ENOENT;
2789 }
2790
2791 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2792                                     struct usb_descriptor_header *desc,
2793                                     void *priv)
2794 {
2795         struct usb_endpoint_descriptor *ds = (void *)desc;
2796         struct ffs_function *func = priv;
2797         struct ffs_ep *ffs_ep;
2798         unsigned ep_desc_id;
2799         int idx;
2800         static const char *speed_names[] = { "full", "high", "super" };
2801
2802         if (type != FFS_DESCRIPTOR)
2803                 return 0;
2804
2805         /*
2806          * If ss_descriptors is not NULL, we are reading super speed
2807          * descriptors; if hs_descriptors is not NULL, we are reading high
2808          * speed descriptors; otherwise, we are reading full speed
2809          * descriptors.
2810          */
2811         if (func->function.ss_descriptors) {
2812                 ep_desc_id = 2;
2813                 func->function.ss_descriptors[(long)valuep] = desc;
2814         } else if (func->function.hs_descriptors) {
2815                 ep_desc_id = 1;
2816                 func->function.hs_descriptors[(long)valuep] = desc;
2817         } else {
2818                 ep_desc_id = 0;
2819                 func->function.fs_descriptors[(long)valuep]    = desc;
2820         }
2821
2822         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2823                 return 0;
2824
2825         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2826         if (idx < 0)
2827                 return idx;
2828
2829         ffs_ep = func->eps + idx;
2830
2831         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2832                 pr_err("two %sspeed descriptors for EP %d\n",
2833                           speed_names[ep_desc_id],
2834                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2835                 return -EINVAL;
2836         }
2837         ffs_ep->descs[ep_desc_id] = ds;
2838
2839         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2840         if (ffs_ep->ep) {
2841                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2842                 if (!ds->wMaxPacketSize)
2843                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2844         } else {
2845                 struct usb_request *req;
2846                 struct usb_ep *ep;
2847                 u8 bEndpointAddress;
2848                 u16 wMaxPacketSize;
2849
2850                 /*
2851                  * We back up bEndpointAddress because autoconfig overwrites
2852                  * it with physical endpoint address.
2853                  */
2854                 bEndpointAddress = ds->bEndpointAddress;
2855                 /*
2856                  * We back up wMaxPacketSize because autoconfig treats
2857                  * endpoint descriptors as if they were full speed.
2858                  */
2859                 wMaxPacketSize = ds->wMaxPacketSize;
2860                 pr_vdebug("autoconfig\n");
2861                 ep = usb_ep_autoconfig(func->gadget, ds);
2862                 if (unlikely(!ep))
2863                         return -ENOTSUPP;
2864                 ep->driver_data = func->eps + idx;
2865
2866                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2867                 if (unlikely(!req))
2868                         return -ENOMEM;
2869
2870                 ffs_ep->ep  = ep;
2871                 ffs_ep->req = req;
2872                 func->eps_revmap[ds->bEndpointAddress &
2873                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2874                 /*
2875                  * If we use virtual address mapping, we restore
2876                  * original bEndpointAddress value.
2877                  */
2878                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2879                         ds->bEndpointAddress = bEndpointAddress;
2880                 /*
2881                  * Restore wMaxPacketSize which was potentially
2882                  * overwritten by autoconfig.
2883                  */
2884                 ds->wMaxPacketSize = wMaxPacketSize;
2885         }
2886         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2887
2888         return 0;
2889 }
2890
2891 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2892                                    struct usb_descriptor_header *desc,
2893                                    void *priv)
2894 {
2895         struct ffs_function *func = priv;
2896         unsigned idx;
2897         u8 newValue;
2898
2899         switch (type) {
2900         default:
2901         case FFS_DESCRIPTOR:
2902                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2903                 return 0;
2904
2905         case FFS_INTERFACE:
2906                 idx = *valuep;
2907                 if (func->interfaces_nums[idx] < 0) {
2908                         int id = usb_interface_id(func->conf, &func->function);
2909                         if (unlikely(id < 0))
2910                                 return id;
2911                         func->interfaces_nums[idx] = id;
2912                 }
2913                 newValue = func->interfaces_nums[idx];
2914                 break;
2915
2916         case FFS_STRING:
2917                 /* String' IDs are allocated when fsf_data is bound to cdev */
2918                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2919                 break;
2920
2921         case FFS_ENDPOINT:
2922                 /*
2923                  * USB_DT_ENDPOINT are handled in
2924                  * __ffs_func_bind_do_descs().
2925                  */
2926                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2927                         return 0;
2928
2929                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2930                 if (unlikely(!func->eps[idx].ep))
2931                         return -EINVAL;
2932
2933                 {
2934                         struct usb_endpoint_descriptor **descs;
2935                         descs = func->eps[idx].descs;
2936                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2937                 }
2938                 break;
2939         }
2940
2941         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2942         *valuep = newValue;
2943         return 0;
2944 }
2945
2946 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2947                                       struct usb_os_desc_header *h, void *data,
2948                                       unsigned len, void *priv)
2949 {
2950         struct ffs_function *func = priv;
2951         u8 length = 0;
2952
2953         switch (type) {
2954         case FFS_OS_DESC_EXT_COMPAT: {
2955                 struct usb_ext_compat_desc *desc = data;
2956                 struct usb_os_desc_table *t;
2957
2958                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2959                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2960                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2961                        ARRAY_SIZE(desc->CompatibleID) +
2962                        ARRAY_SIZE(desc->SubCompatibleID));
2963                 length = sizeof(*desc);
2964         }
2965                 break;
2966         case FFS_OS_DESC_EXT_PROP: {
2967                 struct usb_ext_prop_desc *desc = data;
2968                 struct usb_os_desc_table *t;
2969                 struct usb_os_desc_ext_prop *ext_prop;
2970                 char *ext_prop_name;
2971                 char *ext_prop_data;
2972
2973                 t = &func->function.os_desc_table[h->interface];
2974                 t->if_id = func->interfaces_nums[h->interface];
2975
2976                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2977                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2978
2979                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2980                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2981                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2982                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2983                 length = ext_prop->name_len + ext_prop->data_len + 14;
2984
2985                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2986                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2987                         ext_prop->name_len;
2988
2989                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2990                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2991                         ext_prop->data_len;
2992                 memcpy(ext_prop_data,
2993                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2994                        ext_prop->data_len);
2995                 /* unicode data reported to the host as "WCHAR"s */
2996                 switch (ext_prop->type) {
2997                 case USB_EXT_PROP_UNICODE:
2998                 case USB_EXT_PROP_UNICODE_ENV:
2999                 case USB_EXT_PROP_UNICODE_LINK:
3000                 case USB_EXT_PROP_UNICODE_MULTI:
3001                         ext_prop->data_len *= 2;
3002                         break;
3003                 }
3004                 ext_prop->data = ext_prop_data;
3005
3006                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3007                        ext_prop->name_len);
3008                 /* property name reported to the host as "WCHAR"s */
3009                 ext_prop->name_len *= 2;
3010                 ext_prop->name = ext_prop_name;
3011
3012                 t->os_desc->ext_prop_len +=
3013                         ext_prop->name_len + ext_prop->data_len + 14;
3014                 ++t->os_desc->ext_prop_count;
3015                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3016         }
3017                 break;
3018         default:
3019                 pr_vdebug("unknown descriptor: %d\n", type);
3020         }
3021
3022         return length;
3023 }
3024
3025 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3026                                                 struct usb_configuration *c)
3027 {
3028         struct ffs_function *func = ffs_func_from_usb(f);
3029         struct f_fs_opts *ffs_opts =
3030                 container_of(f->fi, struct f_fs_opts, func_inst);
3031         int ret;
3032
3033         ENTER();
3034
3035         /*
3036          * Legacy gadget triggers binding in functionfs_ready_callback,
3037          * which already uses locking; taking the same lock here would
3038          * cause a deadlock.
3039          *
3040          * Configfs-enabled gadgets however do need ffs_dev_lock.
3041          */
3042         if (!ffs_opts->no_configfs)
3043                 ffs_dev_lock();
3044         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3045         func->ffs = ffs_opts->dev->ffs_data;
3046         if (!ffs_opts->no_configfs)
3047                 ffs_dev_unlock();
3048         if (ret)
3049                 return ERR_PTR(ret);
3050
3051         func->conf = c;
3052         func->gadget = c->cdev->gadget;
3053
3054         /*
3055          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3056          * configurations are bound in sequence with list_for_each_entry,
3057          * in each configuration its functions are bound in sequence
3058          * with list_for_each_entry, so we assume no race condition
3059          * with regard to ffs_opts->bound access
3060          */
3061         if (!ffs_opts->refcnt) {
3062                 ret = functionfs_bind(func->ffs, c->cdev);
3063                 if (ret)
3064                         return ERR_PTR(ret);
3065         }
3066         ffs_opts->refcnt++;
3067         func->function.strings = func->ffs->stringtabs;
3068
3069         return ffs_opts;
3070 }
3071
3072 static int _ffs_func_bind(struct usb_configuration *c,
3073                           struct usb_function *f)
3074 {
3075         struct ffs_function *func = ffs_func_from_usb(f);
3076         struct ffs_data *ffs = func->ffs;
3077
3078         const int full = !!func->ffs->fs_descs_count;
3079         const int high = !!func->ffs->hs_descs_count;
3080         const int super = !!func->ffs->ss_descs_count;
3081
3082         int fs_len, hs_len, ss_len, ret, i;
3083         struct ffs_ep *eps_ptr;
3084
3085         /* Make it a single chunk, less management later on */
3086         vla_group(d);
3087         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3088         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3089                 full ? ffs->fs_descs_count + 1 : 0);
3090         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3091                 high ? ffs->hs_descs_count + 1 : 0);
3092         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3093                 super ? ffs->ss_descs_count + 1 : 0);
3094         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3095         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3096                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3097         vla_item_with_sz(d, char[16], ext_compat,
3098                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3099         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3100                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3101         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3102                          ffs->ms_os_descs_ext_prop_count);
3103         vla_item_with_sz(d, char, ext_prop_name,
3104                          ffs->ms_os_descs_ext_prop_name_len);
3105         vla_item_with_sz(d, char, ext_prop_data,
3106                          ffs->ms_os_descs_ext_prop_data_len);
3107         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3108         char *vlabuf;
3109
3110         ENTER();
3111
3112         /* Has descriptors only for speeds gadget does not support */
3113         if (unlikely(!(full | high | super)))
3114                 return -ENOTSUPP;
3115
3116         /* Allocate a single chunk, less management later on */
3117         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3118         if (unlikely(!vlabuf))
3119                 return -ENOMEM;
3120
3121         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3122         ffs->ms_os_descs_ext_prop_name_avail =
3123                 vla_ptr(vlabuf, d, ext_prop_name);
3124         ffs->ms_os_descs_ext_prop_data_avail =
3125                 vla_ptr(vlabuf, d, ext_prop_data);
3126
3127         /* Copy descriptors  */
3128         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3129                ffs->raw_descs_length);
3130
3131         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3132         eps_ptr = vla_ptr(vlabuf, d, eps);
3133         for (i = 0; i < ffs->eps_count; i++)
3134                 eps_ptr[i].num = -1;
3135
3136         /* Save pointers
3137          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3138         */
3139         func->eps             = vla_ptr(vlabuf, d, eps);
3140         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3141
3142         /*
3143          * Go through all the endpoint descriptors and allocate
3144          * endpoints first, so that later we can rewrite the endpoint
3145          * numbers without worrying that it may be described later on.
3146          */
3147         if (likely(full)) {
3148                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3149                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3150                                       vla_ptr(vlabuf, d, raw_descs),
3151                                       d_raw_descs__sz,
3152                                       __ffs_func_bind_do_descs, func);
3153                 if (unlikely(fs_len < 0)) {
3154                         ret = fs_len;
3155                         goto error;
3156                 }
3157         } else {
3158                 fs_len = 0;
3159         }
3160
3161         if (likely(high)) {
3162                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3163                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3164                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3165                                       d_raw_descs__sz - fs_len,
3166                                       __ffs_func_bind_do_descs, func);
3167                 if (unlikely(hs_len < 0)) {
3168                         ret = hs_len;
3169                         goto error;
3170                 }
3171         } else {
3172                 hs_len = 0;
3173         }
3174
3175         if (likely(super)) {
3176                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3177                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3178                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3179                                 d_raw_descs__sz - fs_len - hs_len,
3180                                 __ffs_func_bind_do_descs, func);
3181                 if (unlikely(ss_len < 0)) {
3182                         ret = ss_len;
3183                         goto error;
3184                 }
3185         } else {
3186                 ss_len = 0;
3187         }
3188
3189         /*
3190          * Now handle interface numbers allocation and interface and
3191          * endpoint numbers rewriting.  We can do that in one go
3192          * now.
3193          */
3194         ret = ffs_do_descs(ffs->fs_descs_count +
3195                            (high ? ffs->hs_descs_count : 0) +
3196                            (super ? ffs->ss_descs_count : 0),
3197                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3198                            __ffs_func_bind_do_nums, func);
3199         if (unlikely(ret < 0))
3200                 goto error;
3201
3202         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3203         if (c->cdev->use_os_string) {
3204                 for (i = 0; i < ffs->interfaces_count; ++i) {
3205                         struct usb_os_desc *desc;
3206
3207                         desc = func->function.os_desc_table[i].os_desc =
3208                                 vla_ptr(vlabuf, d, os_desc) +
3209                                 i * sizeof(struct usb_os_desc);
3210                         desc->ext_compat_id =
3211                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3212                         INIT_LIST_HEAD(&desc->ext_prop);
3213                 }
3214                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3215                                       vla_ptr(vlabuf, d, raw_descs) +
3216                                       fs_len + hs_len + ss_len,
3217                                       d_raw_descs__sz - fs_len - hs_len -
3218                                       ss_len,
3219                                       __ffs_func_bind_do_os_desc, func);
3220                 if (unlikely(ret < 0))
3221                         goto error;
3222         }
3223         func->function.os_desc_n =
3224                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3225
3226         /* And we're done */
3227         ffs_event_add(ffs, FUNCTIONFS_BIND);
3228         return 0;
3229
3230 error:
3231         /* XXX Do we need to release all claimed endpoints here? */
3232         return ret;
3233 }
3234
3235 static int ffs_func_bind(struct usb_configuration *c,
3236                          struct usb_function *f)
3237 {
3238         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3239         struct ffs_function *func = ffs_func_from_usb(f);
3240         int ret;
3241
3242         if (IS_ERR(ffs_opts))
3243                 return PTR_ERR(ffs_opts);
3244
3245         ret = _ffs_func_bind(c, f);
3246         if (ret && !--ffs_opts->refcnt)
3247                 functionfs_unbind(func->ffs);
3248
3249         return ret;
3250 }
3251
3252
3253 /* Other USB function hooks *************************************************/
3254
3255 static void ffs_reset_work(struct work_struct *work)
3256 {
3257         struct ffs_data *ffs = container_of(work,
3258                 struct ffs_data, reset_work);
3259         ffs_data_reset(ffs);
3260 }
3261
3262 static int ffs_func_set_alt(struct usb_function *f,
3263                             unsigned interface, unsigned alt)
3264 {
3265         struct ffs_function *func = ffs_func_from_usb(f);
3266         struct ffs_data *ffs = func->ffs;
3267         int ret = 0, intf;
3268
3269         if (alt != (unsigned)-1) {
3270                 intf = ffs_func_revmap_intf(func, interface);
3271                 if (unlikely(intf < 0))
3272                         return intf;
3273         }
3274
3275         if (ffs->func)
3276                 ffs_func_eps_disable(ffs->func);
3277
3278         if (ffs->state == FFS_DEACTIVATED) {
3279                 ffs->state = FFS_CLOSING;
3280                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3281                 schedule_work(&ffs->reset_work);
3282                 return -ENODEV;
3283         }
3284
3285         if (ffs->state != FFS_ACTIVE)
3286                 return -ENODEV;
3287
3288         if (alt == (unsigned)-1) {
3289                 ffs->func = NULL;
3290                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3291                 return 0;
3292         }
3293
3294         ffs->func = func;
3295         ret = ffs_func_eps_enable(func);
3296         if (likely(ret >= 0))
3297                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3298         return ret;
3299 }
3300
3301 static void ffs_func_disable(struct usb_function *f)
3302 {
3303         ffs_func_set_alt(f, 0, (unsigned)-1);
3304 }
3305
3306 static int ffs_func_setup(struct usb_function *f,
3307                           const struct usb_ctrlrequest *creq)
3308 {
3309         struct ffs_function *func = ffs_func_from_usb(f);
3310         struct ffs_data *ffs = func->ffs;
3311         unsigned long flags;
3312         int ret;
3313
3314         ENTER();
3315
3316         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3317         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3318         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3319         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3320         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3321
3322         /*
3323          * Most requests directed to interface go through here
3324          * (notable exceptions are set/get interface) so we need to
3325          * handle them.  All other either handled by composite or
3326          * passed to usb_configuration->setup() (if one is set).  No
3327          * matter, we will handle requests directed to endpoint here
3328          * as well (as it's straightforward).  Other request recipient
3329          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3330          * is being used.
3331          */
3332         if (ffs->state != FFS_ACTIVE)
3333                 return -ENODEV;
3334
3335         switch (creq->bRequestType & USB_RECIP_MASK) {
3336         case USB_RECIP_INTERFACE:
3337                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3338                 if (unlikely(ret < 0))
3339                         return ret;
3340                 break;
3341
3342         case USB_RECIP_ENDPOINT:
3343                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3344                 if (unlikely(ret < 0))
3345                         return ret;
3346                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3347                         ret = func->ffs->eps_addrmap[ret];
3348                 break;
3349
3350         default:
3351                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3352                         ret = le16_to_cpu(creq->wIndex);
3353                 else
3354                         return -EOPNOTSUPP;
3355         }
3356
3357         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3358         ffs->ev.setup = *creq;
3359         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3360         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3361         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3362
3363         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3364 }
3365
3366 static bool ffs_func_req_match(struct usb_function *f,
3367                                const struct usb_ctrlrequest *creq,
3368                                bool config0)
3369 {
3370         struct ffs_function *func = ffs_func_from_usb(f);
3371
3372         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3373                 return false;
3374
3375         switch (creq->bRequestType & USB_RECIP_MASK) {
3376         case USB_RECIP_INTERFACE:
3377                 return (ffs_func_revmap_intf(func,
3378                                              le16_to_cpu(creq->wIndex)) >= 0);
3379         case USB_RECIP_ENDPOINT:
3380                 return (ffs_func_revmap_ep(func,
3381                                            le16_to_cpu(creq->wIndex)) >= 0);
3382         default:
3383                 return (bool) (func->ffs->user_flags &
3384                                FUNCTIONFS_ALL_CTRL_RECIP);
3385         }
3386 }
3387
3388 static void ffs_func_suspend(struct usb_function *f)
3389 {
3390         ENTER();
3391         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3392 }
3393
3394 static void ffs_func_resume(struct usb_function *f)
3395 {
3396         ENTER();
3397         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3398 }
3399
3400
3401 /* Endpoint and interface numbers reverse mapping ***************************/
3402
3403 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3404 {
3405         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3406         return num ? num : -EDOM;
3407 }
3408
3409 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3410 {
3411         short *nums = func->interfaces_nums;
3412         unsigned count = func->ffs->interfaces_count;
3413
3414         for (; count; --count, ++nums) {
3415                 if (*nums >= 0 && *nums == intf)
3416                         return nums - func->interfaces_nums;
3417         }
3418
3419         return -EDOM;
3420 }
3421
3422
3423 /* Devices management *******************************************************/
3424
3425 static LIST_HEAD(ffs_devices);
3426
3427 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3428 {
3429         struct ffs_dev *dev;
3430
3431         if (!name)
3432                 return NULL;
3433
3434         list_for_each_entry(dev, &ffs_devices, entry) {
3435                 if (strcmp(dev->name, name) == 0)
3436                         return dev;
3437         }
3438
3439         return NULL;
3440 }
3441
3442 /*
3443  * ffs_lock must be taken by the caller of this function
3444  */
3445 static struct ffs_dev *_ffs_get_single_dev(void)
3446 {
3447         struct ffs_dev *dev;
3448
3449         if (list_is_singular(&ffs_devices)) {
3450                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3451                 if (dev->single)
3452                         return dev;
3453         }
3454
3455         return NULL;
3456 }
3457
3458 /*
3459  * ffs_lock must be taken by the caller of this function
3460  */
3461 static struct ffs_dev *_ffs_find_dev(const char *name)
3462 {
3463         struct ffs_dev *dev;
3464
3465         dev = _ffs_get_single_dev();
3466         if (dev)
3467                 return dev;
3468
3469         return _ffs_do_find_dev(name);
3470 }
3471
3472 /* Configfs support *********************************************************/
3473
3474 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3475 {
3476         return container_of(to_config_group(item), struct f_fs_opts,
3477                             func_inst.group);
3478 }
3479
3480 static void ffs_attr_release(struct config_item *item)
3481 {
3482         struct f_fs_opts *opts = to_ffs_opts(item);
3483
3484         usb_put_function_instance(&opts->func_inst);
3485 }
3486
3487 static struct configfs_item_operations ffs_item_ops = {
3488         .release        = ffs_attr_release,
3489 };
3490
3491 static const struct config_item_type ffs_func_type = {
3492         .ct_item_ops    = &ffs_item_ops,
3493         .ct_owner       = THIS_MODULE,
3494 };
3495
3496
3497 /* Function registration interface ******************************************/
3498
3499 static void ffs_free_inst(struct usb_function_instance *f)
3500 {
3501         struct f_fs_opts *opts;
3502
3503         opts = to_f_fs_opts(f);
3504         ffs_dev_lock();
3505         _ffs_free_dev(opts->dev);
3506         ffs_dev_unlock();
3507         kfree(opts);
3508 }
3509
3510 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3511 {
3512         if (strlen(name) >= FIELD_SIZEOF(struct ffs_dev, name))
3513                 return -ENAMETOOLONG;
3514         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3515 }
3516
3517 static struct usb_function_instance *ffs_alloc_inst(void)
3518 {
3519         struct f_fs_opts *opts;
3520         struct ffs_dev *dev;
3521
3522         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3523         if (!opts)
3524                 return ERR_PTR(-ENOMEM);
3525
3526         opts->func_inst.set_inst_name = ffs_set_inst_name;
3527         opts->func_inst.free_func_inst = ffs_free_inst;
3528         ffs_dev_lock();
3529         dev = _ffs_alloc_dev();
3530         ffs_dev_unlock();
3531         if (IS_ERR(dev)) {
3532                 kfree(opts);
3533                 return ERR_CAST(dev);
3534         }
3535         opts->dev = dev;
3536         dev->opts = opts;
3537
3538         config_group_init_type_name(&opts->func_inst.group, "",
3539                                     &ffs_func_type);
3540         return &opts->func_inst;
3541 }
3542
3543 static void ffs_free(struct usb_function *f)
3544 {
3545         kfree(ffs_func_from_usb(f));
3546 }
3547
3548 static void ffs_func_unbind(struct usb_configuration *c,
3549                             struct usb_function *f)
3550 {
3551         struct ffs_function *func = ffs_func_from_usb(f);
3552         struct ffs_data *ffs = func->ffs;
3553         struct f_fs_opts *opts =
3554                 container_of(f->fi, struct f_fs_opts, func_inst);
3555         struct ffs_ep *ep = func->eps;
3556         unsigned count = ffs->eps_count;
3557         unsigned long flags;
3558
3559         ENTER();
3560         if (ffs->func == func) {
3561                 ffs_func_eps_disable(func);
3562                 ffs->func = NULL;
3563         }
3564
3565         if (!--opts->refcnt)
3566                 functionfs_unbind(ffs);
3567
3568         /* cleanup after autoconfig */
3569         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3570         while (count--) {
3571                 if (ep->ep && ep->req)
3572                         usb_ep_free_request(ep->ep, ep->req);
3573                 ep->req = NULL;
3574                 ++ep;
3575         }
3576         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3577         kfree(func->eps);
3578         func->eps = NULL;
3579         /*
3580          * eps, descriptors and interfaces_nums are allocated in the
3581          * same chunk so only one free is required.
3582          */
3583         func->function.fs_descriptors = NULL;
3584         func->function.hs_descriptors = NULL;
3585         func->function.ss_descriptors = NULL;
3586         func->interfaces_nums = NULL;
3587
3588         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3589 }
3590
3591 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3592 {
3593         struct ffs_function *func;
3594
3595         ENTER();
3596
3597         func = kzalloc(sizeof(*func), GFP_KERNEL);
3598         if (unlikely(!func))
3599                 return ERR_PTR(-ENOMEM);
3600
3601         func->function.name    = "Function FS Gadget";
3602
3603         func->function.bind    = ffs_func_bind;
3604         func->function.unbind  = ffs_func_unbind;
3605         func->function.set_alt = ffs_func_set_alt;
3606         func->function.disable = ffs_func_disable;
3607         func->function.setup   = ffs_func_setup;
3608         func->function.req_match = ffs_func_req_match;
3609         func->function.suspend = ffs_func_suspend;
3610         func->function.resume  = ffs_func_resume;
3611         func->function.free_func = ffs_free;
3612
3613         return &func->function;
3614 }
3615
3616 /*
3617  * ffs_lock must be taken by the caller of this function
3618  */
3619 static struct ffs_dev *_ffs_alloc_dev(void)
3620 {
3621         struct ffs_dev *dev;
3622         int ret;
3623
3624         if (_ffs_get_single_dev())
3625                         return ERR_PTR(-EBUSY);
3626
3627         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3628         if (!dev)
3629                 return ERR_PTR(-ENOMEM);
3630
3631         if (list_empty(&ffs_devices)) {
3632                 ret = functionfs_init();
3633                 if (ret) {
3634                         kfree(dev);
3635                         return ERR_PTR(ret);
3636                 }
3637         }
3638
3639         list_add(&dev->entry, &ffs_devices);
3640
3641         return dev;
3642 }
3643
3644 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3645 {
3646         struct ffs_dev *existing;
3647         int ret = 0;
3648
3649         ffs_dev_lock();
3650
3651         existing = _ffs_do_find_dev(name);
3652         if (!existing)
3653                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3654         else if (existing != dev)
3655                 ret = -EBUSY;
3656
3657         ffs_dev_unlock();
3658
3659         return ret;
3660 }
3661 EXPORT_SYMBOL_GPL(ffs_name_dev);
3662
3663 int ffs_single_dev(struct ffs_dev *dev)
3664 {
3665         int ret;
3666
3667         ret = 0;
3668         ffs_dev_lock();
3669
3670         if (!list_is_singular(&ffs_devices))
3671                 ret = -EBUSY;
3672         else
3673                 dev->single = true;
3674
3675         ffs_dev_unlock();
3676         return ret;
3677 }
3678 EXPORT_SYMBOL_GPL(ffs_single_dev);
3679
3680 /*
3681  * ffs_lock must be taken by the caller of this function
3682  */
3683 static void _ffs_free_dev(struct ffs_dev *dev)
3684 {
3685         list_del(&dev->entry);
3686
3687         /* Clear the private_data pointer to stop incorrect dev access */
3688         if (dev->ffs_data)
3689                 dev->ffs_data->private_data = NULL;
3690
3691         kfree(dev);
3692         if (list_empty(&ffs_devices))
3693                 functionfs_cleanup();
3694 }
3695
3696 static void *ffs_acquire_dev(const char *dev_name)
3697 {
3698         struct ffs_dev *ffs_dev;
3699
3700         ENTER();
3701         ffs_dev_lock();
3702
3703         ffs_dev = _ffs_find_dev(dev_name);
3704         if (!ffs_dev)
3705                 ffs_dev = ERR_PTR(-ENOENT);
3706         else if (ffs_dev->mounted)
3707                 ffs_dev = ERR_PTR(-EBUSY);
3708         else if (ffs_dev->ffs_acquire_dev_callback &&
3709             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3710                 ffs_dev = ERR_PTR(-ENOENT);
3711         else
3712                 ffs_dev->mounted = true;
3713
3714         ffs_dev_unlock();
3715         return ffs_dev;
3716 }
3717
3718 static void ffs_release_dev(struct ffs_data *ffs_data)
3719 {
3720         struct ffs_dev *ffs_dev;
3721
3722         ENTER();
3723         ffs_dev_lock();
3724
3725         ffs_dev = ffs_data->private_data;
3726         if (ffs_dev) {
3727                 ffs_dev->mounted = false;
3728
3729                 if (ffs_dev->ffs_release_dev_callback)
3730                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3731         }
3732
3733         ffs_dev_unlock();
3734 }
3735
3736 static int ffs_ready(struct ffs_data *ffs)
3737 {
3738         struct ffs_dev *ffs_obj;
3739         int ret = 0;
3740
3741         ENTER();
3742         ffs_dev_lock();
3743
3744         ffs_obj = ffs->private_data;
3745         if (!ffs_obj) {
3746                 ret = -EINVAL;
3747                 goto done;
3748         }
3749         if (WARN_ON(ffs_obj->desc_ready)) {
3750                 ret = -EBUSY;
3751                 goto done;
3752         }
3753
3754         ffs_obj->desc_ready = true;
3755         ffs_obj->ffs_data = ffs;
3756
3757         if (ffs_obj->ffs_ready_callback) {
3758                 ret = ffs_obj->ffs_ready_callback(ffs);
3759                 if (ret)
3760                         goto done;
3761         }
3762
3763         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3764 done:
3765         ffs_dev_unlock();
3766         return ret;
3767 }
3768
3769 static void ffs_closed(struct ffs_data *ffs)
3770 {
3771         struct ffs_dev *ffs_obj;
3772         struct f_fs_opts *opts;
3773         struct config_item *ci;
3774
3775         ENTER();
3776         ffs_dev_lock();
3777
3778         ffs_obj = ffs->private_data;
3779         if (!ffs_obj)
3780                 goto done;
3781
3782         ffs_obj->desc_ready = false;
3783         ffs_obj->ffs_data = NULL;
3784
3785         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3786             ffs_obj->ffs_closed_callback)
3787                 ffs_obj->ffs_closed_callback(ffs);
3788
3789         if (ffs_obj->opts)
3790                 opts = ffs_obj->opts;
3791         else
3792                 goto done;
3793
3794         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3795             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3796                 goto done;
3797
3798         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3799         ffs_dev_unlock();
3800
3801         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3802                 unregister_gadget_item(ci);
3803         return;
3804 done:
3805         ffs_dev_unlock();
3806 }
3807
3808 /* Misc helper functions ****************************************************/
3809
3810 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3811 {
3812         return nonblock
3813                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3814                 : mutex_lock_interruptible(mutex);
3815 }
3816
3817 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3818 {
3819         char *data;
3820
3821         if (unlikely(!len))
3822                 return NULL;
3823
3824         data = kmalloc(len, GFP_KERNEL);
3825         if (unlikely(!data))
3826                 return ERR_PTR(-ENOMEM);
3827
3828         if (unlikely(copy_from_user(data, buf, len))) {
3829                 kfree(data);
3830                 return ERR_PTR(-EFAULT);
3831         }
3832
3833         pr_vdebug("Buffer from user space:\n");
3834         ffs_dump_mem("", data, len);
3835
3836         return data;
3837 }
3838
3839 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3840 MODULE_LICENSE("GPL");
3841 MODULE_AUTHOR("Michal Nazarewicz");