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