drivers/usb/gadget/function/f_fs.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_fs.c -- user mode file system API for USB composite function controllers
   4  *
   5  * Copyright (C) 2010 Samsung Electronics
   6  * Author: Michal Nazarewicz <mina86@mina86.com>
   7  *
   8  * Based on inode.c (GadgetFS) which was:
   9  * Copyright (C) 2003-2004 David Brownell
  10  * Copyright (C) 2003 Agilent Technologies
  11  */
  12
  13
  14 /* #define DEBUG */
  15 /* #define VERBOSE_DEBUG */
  16
  17 #include <linux/blkdev.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/export.h>
  20 #include <linux/hid.h>
  21 #include <linux/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                 use_mm(io_data->mm);
 762                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 763                 unuse_mm(io_data->mm);
 764         }
 765
 766         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 767
 768         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 769                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 770
 771         usb_ep_free_request(io_data->ep, io_data->req);
 772
 773         if (io_data->read)
 774                 kfree(io_data->to_free);
 775         kfree(io_data->buf);
 776         kfree(io_data);
 777 }
 778
 779 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 780                                          struct usb_request *req)
 781 {
 782         struct ffs_io_data *io_data = req->context;
 783         struct ffs_data *ffs = io_data->ffs;
 784
 785         ENTER();
 786
 787         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 788         queue_work(ffs->io_completion_wq, &io_data->work);
 789 }
 790
 791 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 792 {
 793         /*
 794          * See comment in struct ffs_epfile for full read_buffer pointer
 795          * synchronisation story.
 796          */
 797         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 798         if (buf && buf != READ_BUFFER_DROP)
 799                 kfree(buf);
 800 }
 801
 802 /* Assumes epfile->mutex is held. */
 803 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 804                                           struct iov_iter *iter)
 805 {
 806         /*
 807          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 808          * the buffer while we are using it.  See comment in struct ffs_epfile
 809          * for full read_buffer pointer synchronisation story.
 810          */
 811         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 812         ssize_t ret;
 813         if (!buf || buf == READ_BUFFER_DROP)
 814                 return 0;
 815
 816         ret = copy_to_iter(buf->data, buf->length, iter);
 817         if (buf->length == ret) {
 818                 kfree(buf);
 819                 return ret;
 820         }
 821
 822         if (unlikely(iov_iter_count(iter))) {
 823                 ret = -EFAULT;
 824         } else {
 825                 buf->length -= ret;
 826                 buf->data += ret;
 827         }
 828
 829         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 830                 kfree(buf);
 831
 832         return ret;
 833 }
 834
 835 /* Assumes epfile->mutex is held. */
 836 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 837                                       void *data, int data_len,
 838                                       struct iov_iter *iter)
 839 {
 840         struct ffs_buffer *buf;
 841
 842         ssize_t ret = copy_to_iter(data, data_len, iter);
 843         if (likely(data_len == ret))
 844                 return ret;
 845
 846         if (unlikely(iov_iter_count(iter)))
 847                 return -EFAULT;
 848
 849         /* See ffs_copy_to_iter for more context. */
 850         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 851                 data_len, ret);
 852
 853         data_len -= ret;
 854         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 855         if (!buf)
 856                 return -ENOMEM;
 857         buf->length = data_len;
 858         buf->data = buf->storage;
 859         memcpy(buf->storage, data + ret, data_len);
 860
 861         /*
 862          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 863          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 864          * in struct ffs_epfile for full read_buffer pointer synchronisation
 865          * story.
 866          */
 867         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 868                 kfree(buf);
 869
 870         return ret;
 871 }
 872
 873 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 874 {
 875         struct ffs_epfile *epfile = file->private_data;
 876         struct usb_request *req;
 877         struct ffs_ep *ep;
 878         char *data = NULL;
 879         ssize_t ret, data_len = -EINVAL;
 880         int halt;
 881
 882         /* Are we still active? */
 883         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 884                 return -ENODEV;
 885
 886         /* Wait for endpoint to be enabled */
 887         ep = epfile->ep;
 888         if (!ep) {
 889                 if (file->f_flags & O_NONBLOCK)
 890                         return -EAGAIN;
 891
 892                 ret = wait_event_interruptible(
 893                                 epfile->ffs->wait, (ep = epfile->ep));
 894                 if (ret)
 895                         return -EINTR;
 896         }
 897
 898         /* Do we halt? */
 899         halt = (!io_data->read == !epfile->in);
 900         if (halt && epfile->isoc)
 901                 return -EINVAL;
 902
 903         /* We will be using request and read_buffer */
 904         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 905         if (unlikely(ret))
 906                 goto error;
 907
 908         /* Allocate & copy */
 909         if (!halt) {
 910                 struct usb_gadget *gadget;
 911
 912                 /*
 913                  * Do we have buffered data from previous partial read?  Check
 914                  * that for synchronous case only because we do not have
 915                  * facility to ‘wake up’ a pending asynchronous read and push
 916                  * buffered data to it which we would need to make things behave
 917                  * consistently.
 918                  */
 919                 if (!io_data->aio && io_data->read) {
 920                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 921                         if (ret)
 922                                 goto error_mutex;
 923                 }
 924
 925                 /*
 926                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 927                  * before the waiting completes, so do not assign to 'gadget'
 928                  * earlier
 929                  */
 930                 gadget = epfile->ffs->gadget;
 931
 932                 spin_lock_irq(&epfile->ffs->eps_lock);
 933                 /* In the meantime, endpoint got disabled or changed. */
 934                 if (epfile->ep != ep) {
 935                         ret = -ESHUTDOWN;
 936                         goto error_lock;
 937                 }
 938                 data_len = iov_iter_count(&io_data->data);
 939                 /*
 940                  * Controller may require buffer size to be aligned to
 941                  * maxpacketsize of an out endpoint.
 942                  */
 943                 if (io_data->read)
 944                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
 945                 spin_unlock_irq(&epfile->ffs->eps_lock);
 946
 947                 data = kmalloc(data_len, GFP_KERNEL);
 948                 if (unlikely(!data)) {
 949                         ret = -ENOMEM;
 950                         goto error_mutex;
 951                 }
 952                 if (!io_data->read &&
 953                     !copy_from_iter_full(data, data_len, &io_data->data)) {
 954                         ret = -EFAULT;
 955                         goto error_mutex;
 956                 }
 957         }
 958
 959         spin_lock_irq(&epfile->ffs->eps_lock);
 960
 961         if (epfile->ep != ep) {
 962                 /* In the meantime, endpoint got disabled or changed. */
 963                 ret = -ESHUTDOWN;
 964         } else if (halt) {
 965                 ret = usb_ep_set_halt(ep->ep);
 966                 if (!ret)
 967                         ret = -EBADMSG;
 968         } else if (unlikely(data_len == -EINVAL)) {
 969                 /*
 970                  * Sanity Check: even though data_len can't be used
 971                  * uninitialized at the time I write this comment, some
 972                  * compilers complain about this situation.
 973                  * In order to keep the code clean from warnings, data_len is
 974                  * being initialized to -EINVAL during its declaration, which
 975                  * means we can't rely on compiler anymore to warn no future
 976                  * changes won't result in data_len being used uninitialized.
 977                  * For such reason, we're adding this redundant sanity check
 978                  * here.
 979                  */
 980                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
 981                 ret = -EINVAL;
 982         } else if (!io_data->aio) {
 983                 DECLARE_COMPLETION_ONSTACK(done);
 984                 bool interrupted = false;
 985
 986                 req = ep->req;
 987                 req->buf      = data;
 988                 req->length   = data_len;
 989
 990                 req->context  = &done;
 991                 req->complete = ffs_epfile_io_complete;
 992
 993                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 994                 if (unlikely(ret < 0))
 995                         goto error_lock;
 996
 997                 spin_unlock_irq(&epfile->ffs->eps_lock);
 998
 999                 if (unlikely(wait_for_completion_interruptible(&done))) {
1000                         /*
1001                          * To avoid race condition with ffs_epfile_io_complete,
1002                          * dequeue the request first then check
1003                          * status. usb_ep_dequeue API should guarantee no race
1004                          * condition with req->complete callback.
1005                          */
1006                         usb_ep_dequeue(ep->ep, req);
1007                         interrupted = ep->status < 0;
1008                 }
1009
1010                 if (interrupted)
1011                         ret = -EINTR;
1012                 else if (io_data->read && ep->status > 0)
1013                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1014                                                      &io_data->data);
1015                 else
1016                         ret = ep->status;
1017                 goto error_mutex;
1018         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1019                 ret = -ENOMEM;
1020         } else {
1021                 req->buf      = data;
1022                 req->length   = data_len;
1023
1024                 io_data->buf = data;
1025                 io_data->ep = ep->ep;
1026                 io_data->req = req;
1027                 io_data->ffs = epfile->ffs;
1028
1029                 req->context  = io_data;
1030                 req->complete = ffs_epfile_async_io_complete;
1031
1032                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1033                 if (unlikely(ret)) {
1034                         usb_ep_free_request(ep->ep, req);
1035                         goto error_lock;
1036                 }
1037
1038                 ret = -EIOCBQUEUED;
1039                 /*
1040                  * Do not kfree the buffer in this function.  It will be freed
1041                  * by ffs_user_copy_worker.
1042                  */
1043                 data = NULL;
1044         }
1045
1046 error_lock:
1047         spin_unlock_irq(&epfile->ffs->eps_lock);
1048 error_mutex:
1049         mutex_unlock(&epfile->mutex);
1050 error:
1051         kfree(data);
1052         return ret;
1053 }
1054
1055 static int
1056 ffs_epfile_open(struct inode *inode, struct file *file)
1057 {
1058         struct ffs_epfile *epfile = inode->i_private;
1059
1060         ENTER();
1061
1062         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1063                 return -ENODEV;
1064
1065         file->private_data = epfile;
1066         ffs_data_opened(epfile->ffs);
1067
1068         return 0;
1069 }
1070
1071 static int ffs_aio_cancel(struct kiocb *kiocb)
1072 {
1073         struct ffs_io_data *io_data = kiocb->private;
1074         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1075         int value;
1076
1077         ENTER();
1078
1079         spin_lock_irq(&epfile->ffs->eps_lock);
1080
1081         if (likely(io_data && io_data->ep && io_data->req))
1082                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1083         else
1084                 value = -EINVAL;
1085
1086         spin_unlock_irq(&epfile->ffs->eps_lock);
1087
1088         return value;
1089 }
1090
1091 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1092 {
1093         struct ffs_io_data io_data, *p = &io_data;
1094         ssize_t res;
1095
1096         ENTER();
1097
1098         if (!is_sync_kiocb(kiocb)) {
1099                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1100                 if (unlikely(!p))
1101                         return -ENOMEM;
1102                 p->aio = true;
1103         } else {
1104                 p->aio = false;
1105         }
1106
1107         p->read = false;
1108         p->kiocb = kiocb;
1109         p->data = *from;
1110         p->mm = current->mm;
1111
1112         kiocb->private = p;
1113
1114         if (p->aio)
1115                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1116
1117         res = ffs_epfile_io(kiocb->ki_filp, p);
1118         if (res == -EIOCBQUEUED)
1119                 return res;
1120         if (p->aio)
1121                 kfree(p);
1122         else
1123                 *from = p->data;
1124         return res;
1125 }
1126
1127 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1128 {
1129         struct ffs_io_data io_data, *p = &io_data;
1130         ssize_t res;
1131
1132         ENTER();
1133
1134         if (!is_sync_kiocb(kiocb)) {
1135                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1136                 if (unlikely(!p))
1137                         return -ENOMEM;
1138                 p->aio = true;
1139         } else {
1140                 p->aio = false;
1141         }
1142
1143         p->read = true;
1144         p->kiocb = kiocb;
1145         if (p->aio) {
1146                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1147                 if (!p->to_free) {
1148                         kfree(p);
1149                         return -ENOMEM;
1150                 }
1151         } else {
1152                 p->data = *to;
1153                 p->to_free = NULL;
1154         }
1155         p->mm = current->mm;
1156
1157         kiocb->private = p;
1158
1159         if (p->aio)
1160                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1161
1162         res = ffs_epfile_io(kiocb->ki_filp, p);
1163         if (res == -EIOCBQUEUED)
1164                 return res;
1165
1166         if (p->aio) {
1167                 kfree(p->to_free);
1168                 kfree(p);
1169         } else {
1170                 *to = p->data;
1171         }
1172         return res;
1173 }
1174
1175 static int
1176 ffs_epfile_release(struct inode *inode, struct file *file)
1177 {
1178         struct ffs_epfile *epfile = inode->i_private;
1179
1180         ENTER();
1181
1182         __ffs_epfile_read_buffer_free(epfile);
1183         ffs_data_closed(epfile->ffs);
1184
1185         return 0;
1186 }
1187
1188 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1189                              unsigned long value)
1190 {
1191         struct ffs_epfile *epfile = file->private_data;
1192         struct ffs_ep *ep;
1193         int ret;
1194
1195         ENTER();
1196
1197         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1198                 return -ENODEV;
1199
1200         /* Wait for endpoint to be enabled */
1201         ep = epfile->ep;
1202         if (!ep) {
1203                 if (file->f_flags & O_NONBLOCK)
1204                         return -EAGAIN;
1205
1206                 ret = wait_event_interruptible(
1207                                 epfile->ffs->wait, (ep = epfile->ep));
1208                 if (ret)
1209                         return -EINTR;
1210         }
1211
1212         spin_lock_irq(&epfile->ffs->eps_lock);
1213
1214         /* In the meantime, endpoint got disabled or changed. */
1215         if (epfile->ep != ep) {
1216                 spin_unlock_irq(&epfile->ffs->eps_lock);
1217                 return -ESHUTDOWN;
1218         }
1219
1220         switch (code) {
1221         case FUNCTIONFS_FIFO_STATUS:
1222                 ret = usb_ep_fifo_status(epfile->ep->ep);
1223                 break;
1224         case FUNCTIONFS_FIFO_FLUSH:
1225                 usb_ep_fifo_flush(epfile->ep->ep);
1226                 ret = 0;
1227                 break;
1228         case FUNCTIONFS_CLEAR_HALT:
1229                 ret = usb_ep_clear_halt(epfile->ep->ep);
1230                 break;
1231         case FUNCTIONFS_ENDPOINT_REVMAP:
1232                 ret = epfile->ep->num;
1233                 break;
1234         case FUNCTIONFS_ENDPOINT_DESC:
1235         {
1236                 int desc_idx;
1237                 struct usb_endpoint_descriptor *desc;
1238
1239                 switch (epfile->ffs->gadget->speed) {
1240                 case USB_SPEED_SUPER:
1241                         desc_idx = 2;
1242                         break;
1243                 case USB_SPEED_HIGH:
1244                         desc_idx = 1;
1245                         break;
1246                 default:
1247                         desc_idx = 0;
1248                 }
1249                 desc = epfile->ep->descs[desc_idx];
1250
1251                 spin_unlock_irq(&epfile->ffs->eps_lock);
1252                 ret = copy_to_user((void __user *)value, desc, desc->bLength);
1253                 if (ret)
1254                         ret = -EFAULT;
1255                 return ret;
1256         }
1257         default:
1258                 ret = -ENOTTY;
1259         }
1260         spin_unlock_irq(&epfile->ffs->eps_lock);
1261
1262         return ret;
1263 }
1264
1265 static const struct file_operations ffs_epfile_operations = {
1266         .llseek =       no_llseek,
1267
1268         .open =         ffs_epfile_open,
1269         .write_iter =   ffs_epfile_write_iter,
1270         .read_iter =    ffs_epfile_read_iter,
1271         .release =      ffs_epfile_release,
1272         .unlocked_ioctl =       ffs_epfile_ioctl,
1273 };
1274
1275
1276 /* File system and super block operations ***********************************/
1277
1278 /*
1279  * Mounting the file system creates a controller file, used first for
1280  * function configuration then later for event monitoring.
1281  */
1282
1283 static struct inode *__must_check
1284 ffs_sb_make_inode(struct super_block *sb, void *data,
1285                   const struct file_operations *fops,
1286                   const struct inode_operations *iops,
1287                   struct ffs_file_perms *perms)
1288 {
1289         struct inode *inode;
1290
1291         ENTER();
1292
1293         inode = new_inode(sb);
1294
1295         if (likely(inode)) {
1296                 struct timespec ts = current_time(inode);
1297
1298                 inode->i_ino     = get_next_ino();
1299                 inode->i_mode    = perms->mode;
1300                 inode->i_uid     = perms->uid;
1301                 inode->i_gid     = perms->gid;
1302                 inode->i_atime   = ts;
1303                 inode->i_mtime   = ts;
1304                 inode->i_ctime   = ts;
1305                 inode->i_private = data;
1306                 if (fops)
1307                         inode->i_fop = fops;
1308                 if (iops)
1309                         inode->i_op  = iops;
1310         }
1311
1312         return inode;
1313 }
1314
1315 /* Create "regular" file */
1316 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1317                                         const char *name, void *data,
1318                                         const struct file_operations *fops)
1319 {
1320         struct ffs_data *ffs = sb->s_fs_info;
1321         struct dentry   *dentry;
1322         struct inode    *inode;
1323
1324         ENTER();
1325
1326         dentry = d_alloc_name(sb->s_root, name);
1327         if (unlikely(!dentry))
1328                 return NULL;
1329
1330         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1331         if (unlikely(!inode)) {
1332                 dput(dentry);
1333                 return NULL;
1334         }
1335
1336         d_add(dentry, inode);
1337         return dentry;
1338 }
1339
1340 /* Super block */
1341 static const struct super_operations ffs_sb_operations = {
1342         .statfs =       simple_statfs,
1343         .drop_inode =   generic_delete_inode,
1344 };
1345
1346 struct ffs_sb_fill_data {
1347         struct ffs_file_perms perms;
1348         umode_t root_mode;
1349         const char *dev_name;
1350         bool no_disconnect;
1351         struct ffs_data *ffs_data;
1352 };
1353
1354 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1355 {
1356         struct ffs_sb_fill_data *data = _data;
1357         struct inode    *inode;
1358         struct ffs_data *ffs = data->ffs_data;
1359
1360         ENTER();
1361
1362         ffs->sb              = sb;
1363         data->ffs_data       = NULL;
1364         sb->s_fs_info        = ffs;
1365         sb->s_blocksize      = PAGE_SIZE;
1366         sb->s_blocksize_bits = PAGE_SHIFT;
1367         sb->s_magic          = FUNCTIONFS_MAGIC;
1368         sb->s_op             = &ffs_sb_operations;
1369         sb->s_time_gran      = 1;
1370
1371         /* Root inode */
1372         data->perms.mode = data->root_mode;
1373         inode = ffs_sb_make_inode(sb, NULL,
1374                                   &simple_dir_operations,
1375                                   &simple_dir_inode_operations,
1376                                   &data->perms);
1377         sb->s_root = d_make_root(inode);
1378         if (unlikely(!sb->s_root))
1379                 return -ENOMEM;
1380
1381         /* EP0 file */
1382         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1383                                          &ffs_ep0_operations)))
1384                 return -ENOMEM;
1385
1386         return 0;
1387 }
1388
1389 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1390 {
1391         ENTER();
1392
1393         if (!opts || !*opts)
1394                 return 0;
1395
1396         for (;;) {
1397                 unsigned long value;
1398                 char *eq, *comma;
1399
1400                 /* Option limit */
1401                 comma = strchr(opts, ',');
1402                 if (comma)
1403                         *comma = 0;
1404
1405                 /* Value limit */
1406                 eq = strchr(opts, '=');
1407                 if (unlikely(!eq)) {
1408                         pr_err("'=' missing in %s\n", opts);
1409                         return -EINVAL;
1410                 }
1411                 *eq = 0;
1412
1413                 /* Parse value */
1414                 if (kstrtoul(eq + 1, 0, &value)) {
1415                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1416                         return -EINVAL;
1417                 }
1418
1419                 /* Interpret option */
1420                 switch (eq - opts) {
1421                 case 13:
1422                         if (!memcmp(opts, "no_disconnect", 13))
1423                                 data->no_disconnect = !!value;
1424                         else
1425                                 goto invalid;
1426                         break;
1427                 case 5:
1428                         if (!memcmp(opts, "rmode", 5))
1429                                 data->root_mode  = (value & 0555) | S_IFDIR;
1430                         else if (!memcmp(opts, "fmode", 5))
1431                                 data->perms.mode = (value & 0666) | S_IFREG;
1432                         else
1433                                 goto invalid;
1434                         break;
1435
1436                 case 4:
1437                         if (!memcmp(opts, "mode", 4)) {
1438                                 data->root_mode  = (value & 0555) | S_IFDIR;
1439                                 data->perms.mode = (value & 0666) | S_IFREG;
1440                         } else {
1441                                 goto invalid;
1442                         }
1443                         break;
1444
1445                 case 3:
1446                         if (!memcmp(opts, "uid", 3)) {
1447                                 data->perms.uid = make_kuid(current_user_ns(), value);
1448                                 if (!uid_valid(data->perms.uid)) {
1449                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1450                                         return -EINVAL;
1451                                 }
1452                         } else if (!memcmp(opts, "gid", 3)) {
1453                                 data->perms.gid = make_kgid(current_user_ns(), value);
1454                                 if (!gid_valid(data->perms.gid)) {
1455                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1456                                         return -EINVAL;
1457                                 }
1458                         } else {
1459                                 goto invalid;
1460                         }
1461                         break;
1462
1463                 default:
1464 invalid:
1465                         pr_err("%s: invalid option\n", opts);
1466                         return -EINVAL;
1467                 }
1468
1469                 /* Next iteration */
1470                 if (!comma)
1471                         break;
1472                 opts = comma + 1;
1473         }
1474
1475         return 0;
1476 }
1477
1478 /* "mount -t functionfs dev_name /dev/function" ends up here */
1479
1480 static struct dentry *
1481 ffs_fs_mount(struct file_system_type *t, int flags,
1482               const char *dev_name, void *opts)
1483 {
1484         struct ffs_sb_fill_data data = {
1485                 .perms = {
1486                         .mode = S_IFREG | 0600,
1487                         .uid = GLOBAL_ROOT_UID,
1488                         .gid = GLOBAL_ROOT_GID,
1489                 },
1490                 .root_mode = S_IFDIR | 0500,
1491                 .no_disconnect = false,
1492         };
1493         struct dentry *rv;
1494         int ret;
1495         void *ffs_dev;
1496         struct ffs_data *ffs;
1497
1498         ENTER();
1499
1500         ret = ffs_fs_parse_opts(&data, opts);
1501         if (unlikely(ret < 0))
1502                 return ERR_PTR(ret);
1503
1504         ffs = ffs_data_new(dev_name);
1505         if (unlikely(!ffs))
1506                 return ERR_PTR(-ENOMEM);
1507         ffs->file_perms = data.perms;
1508         ffs->no_disconnect = data.no_disconnect;
1509
1510         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1511         if (unlikely(!ffs->dev_name)) {
1512                 ffs_data_put(ffs);
1513                 return ERR_PTR(-ENOMEM);
1514         }
1515
1516         ffs_dev = ffs_acquire_dev(dev_name);
1517         if (IS_ERR(ffs_dev)) {
1518                 ffs_data_put(ffs);
1519                 return ERR_CAST(ffs_dev);
1520         }
1521         ffs->private_data = ffs_dev;
1522         data.ffs_data = ffs;
1523
1524         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1525         if (IS_ERR(rv) && data.ffs_data) {
1526                 ffs_release_dev(data.ffs_data);
1527                 ffs_data_put(data.ffs_data);
1528         }
1529         return rv;
1530 }
1531
1532 static void
1533 ffs_fs_kill_sb(struct super_block *sb)
1534 {
1535         ENTER();
1536
1537         kill_litter_super(sb);
1538         if (sb->s_fs_info) {
1539                 ffs_release_dev(sb->s_fs_info);
1540                 ffs_data_closed(sb->s_fs_info);
1541                 ffs_data_put(sb->s_fs_info);
1542         }
1543 }
1544
1545 static struct file_system_type ffs_fs_type = {
1546         .owner          = THIS_MODULE,
1547         .name           = "functionfs",
1548         .mount          = ffs_fs_mount,
1549         .kill_sb        = ffs_fs_kill_sb,
1550 };
1551 MODULE_ALIAS_FS("functionfs");
1552
1553
1554 /* Driver's main init/cleanup functions *************************************/
1555
1556 static int functionfs_init(void)
1557 {
1558         int ret;
1559
1560         ENTER();
1561
1562         ret = register_filesystem(&ffs_fs_type);
1563         if (likely(!ret))
1564                 pr_info("file system registered\n");
1565         else
1566                 pr_err("failed registering file system (%d)\n", ret);
1567
1568         return ret;
1569 }
1570
1571 static void functionfs_cleanup(void)
1572 {
1573         ENTER();
1574
1575         pr_info("unloading\n");
1576         unregister_filesystem(&ffs_fs_type);
1577 }
1578
1579
1580 /* ffs_data and ffs_function construction and destruction code **************/
1581
1582 static void ffs_data_clear(struct ffs_data *ffs);
1583 static void ffs_data_reset(struct ffs_data *ffs);
1584
1585 static void ffs_data_get(struct ffs_data *ffs)
1586 {
1587         ENTER();
1588
1589         refcount_inc(&ffs->ref);
1590 }
1591
1592 static void ffs_data_opened(struct ffs_data *ffs)
1593 {
1594         ENTER();
1595
1596         refcount_inc(&ffs->ref);
1597         if (atomic_add_return(1, &ffs->opened) == 1 &&
1598                         ffs->state == FFS_DEACTIVATED) {
1599                 ffs->state = FFS_CLOSING;
1600                 ffs_data_reset(ffs);
1601         }
1602 }
1603
1604 static void ffs_data_put(struct ffs_data *ffs)
1605 {
1606         ENTER();
1607
1608         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1609                 pr_info("%s(): freeing\n", __func__);
1610                 ffs_data_clear(ffs);
1611                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1612                        waitqueue_active(&ffs->ep0req_completion.wait) ||
1613                        waitqueue_active(&ffs->wait));
1614                 destroy_workqueue(ffs->io_completion_wq);
1615                 kfree(ffs->dev_name);
1616                 kfree(ffs);
1617         }
1618 }
1619
1620 static void ffs_data_closed(struct ffs_data *ffs)
1621 {
1622         ENTER();
1623
1624         if (atomic_dec_and_test(&ffs->opened)) {
1625                 if (ffs->no_disconnect) {
1626                         ffs->state = FFS_DEACTIVATED;
1627                         if (ffs->epfiles) {
1628                                 ffs_epfiles_destroy(ffs->epfiles,
1629                                                    ffs->eps_count);
1630                                 ffs->epfiles = NULL;
1631                         }
1632                         if (ffs->setup_state == FFS_SETUP_PENDING)
1633                                 __ffs_ep0_stall(ffs);
1634                 } else {
1635                         ffs->state = FFS_CLOSING;
1636                         ffs_data_reset(ffs);
1637                 }
1638         }
1639         if (atomic_read(&ffs->opened) < 0) {
1640                 ffs->state = FFS_CLOSING;
1641                 ffs_data_reset(ffs);
1642         }
1643
1644         ffs_data_put(ffs);
1645 }
1646
1647 static struct ffs_data *ffs_data_new(const char *dev_name)
1648 {
1649         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1650         if (unlikely(!ffs))
1651                 return NULL;
1652
1653         ENTER();
1654
1655         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1656         if (!ffs->io_completion_wq) {
1657                 kfree(ffs);
1658                 return NULL;
1659         }
1660
1661         refcount_set(&ffs->ref, 1);
1662         atomic_set(&ffs->opened, 0);
1663         ffs->state = FFS_READ_DESCRIPTORS;
1664         mutex_init(&ffs->mutex);
1665         spin_lock_init(&ffs->eps_lock);
1666         init_waitqueue_head(&ffs->ev.waitq);
1667         init_waitqueue_head(&ffs->wait);
1668         init_completion(&ffs->ep0req_completion);
1669
1670         /* XXX REVISIT need to update it in some places, or do we? */
1671         ffs->ev.can_stall = 1;
1672
1673         return ffs;
1674 }
1675
1676 static void ffs_data_clear(struct ffs_data *ffs)
1677 {
1678         ENTER();
1679
1680         ffs_closed(ffs);
1681
1682         BUG_ON(ffs->gadget);
1683
1684         if (ffs->epfiles)
1685                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1686
1687         if (ffs->ffs_eventfd)
1688                 eventfd_ctx_put(ffs->ffs_eventfd);
1689
1690         kfree(ffs->raw_descs_data);
1691         kfree(ffs->raw_strings);
1692         kfree(ffs->stringtabs);
1693 }
1694
1695 static void ffs_data_reset(struct ffs_data *ffs)
1696 {
1697         ENTER();
1698
1699         ffs_data_clear(ffs);
1700
1701         ffs->epfiles = NULL;
1702         ffs->raw_descs_data = NULL;
1703         ffs->raw_descs = NULL;
1704         ffs->raw_strings = NULL;
1705         ffs->stringtabs = NULL;
1706
1707         ffs->raw_descs_length = 0;
1708         ffs->fs_descs_count = 0;
1709         ffs->hs_descs_count = 0;
1710         ffs->ss_descs_count = 0;
1711
1712         ffs->strings_count = 0;
1713         ffs->interfaces_count = 0;
1714         ffs->eps_count = 0;
1715
1716         ffs->ev.count = 0;
1717
1718         ffs->state = FFS_READ_DESCRIPTORS;
1719         ffs->setup_state = FFS_NO_SETUP;
1720         ffs->flags = 0;
1721 }
1722
1723
1724 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1725 {
1726         struct usb_gadget_strings **lang;
1727         int first_id;
1728
1729         ENTER();
1730
1731         if (WARN_ON(ffs->state != FFS_ACTIVE
1732                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1733                 return -EBADFD;
1734
1735         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1736         if (unlikely(first_id < 0))
1737                 return first_id;
1738
1739         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1740         if (unlikely(!ffs->ep0req))
1741                 return -ENOMEM;
1742         ffs->ep0req->complete = ffs_ep0_complete;
1743         ffs->ep0req->context = ffs;
1744
1745         lang = ffs->stringtabs;
1746         if (lang) {
1747                 for (; *lang; ++lang) {
1748                         struct usb_string *str = (*lang)->strings;
1749                         int id = first_id;
1750                         for (; str->s; ++id, ++str)
1751                                 str->id = id;
1752                 }
1753         }
1754
1755         ffs->gadget = cdev->gadget;
1756         ffs_data_get(ffs);
1757         return 0;
1758 }
1759
1760 static void functionfs_unbind(struct ffs_data *ffs)
1761 {
1762         ENTER();
1763
1764         if (!WARN_ON(!ffs->gadget)) {
1765                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1766                 ffs->ep0req = NULL;
1767                 ffs->gadget = NULL;
1768                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1769                 ffs_data_put(ffs);
1770         }
1771 }
1772
1773 static int ffs_epfiles_create(struct ffs_data *ffs)
1774 {
1775         struct ffs_epfile *epfile, *epfiles;
1776         unsigned i, count;
1777
1778         ENTER();
1779
1780         count = ffs->eps_count;
1781         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1782         if (!epfiles)
1783                 return -ENOMEM;
1784
1785         epfile = epfiles;
1786         for (i = 1; i <= count; ++i, ++epfile) {
1787                 epfile->ffs = ffs;
1788                 mutex_init(&epfile->mutex);
1789                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1790                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1791                 else
1792                         sprintf(epfile->name, "ep%u", i);
1793                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1794                                                  epfile,
1795                                                  &ffs_epfile_operations);
1796                 if (unlikely(!epfile->dentry)) {
1797                         ffs_epfiles_destroy(epfiles, i - 1);
1798                         return -ENOMEM;
1799                 }
1800         }
1801
1802         ffs->epfiles = epfiles;
1803         return 0;
1804 }
1805
1806 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1807 {
1808         struct ffs_epfile *epfile = epfiles;
1809
1810         ENTER();
1811
1812         for (; count; --count, ++epfile) {
1813                 BUG_ON(mutex_is_locked(&epfile->mutex));
1814                 if (epfile->dentry) {
1815                         d_delete(epfile->dentry);
1816                         dput(epfile->dentry);
1817                         epfile->dentry = NULL;
1818                 }
1819         }
1820
1821         kfree(epfiles);
1822 }
1823
1824 static void ffs_func_eps_disable(struct ffs_function *func)
1825 {
1826         struct ffs_ep *ep         = func->eps;
1827         struct ffs_epfile *epfile = func->ffs->epfiles;
1828         unsigned count            = func->ffs->eps_count;
1829         unsigned long flags;
1830
1831         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1832         while (count--) {
1833                 /* pending requests get nuked */
1834                 if (likely(ep->ep))
1835                         usb_ep_disable(ep->ep);
1836                 ++ep;
1837
1838                 if (epfile) {
1839                         epfile->ep = NULL;
1840                         __ffs_epfile_read_buffer_free(epfile);
1841                         ++epfile;
1842                 }
1843         }
1844         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1845 }
1846
1847 static int ffs_func_eps_enable(struct ffs_function *func)
1848 {
1849         struct ffs_data *ffs      = func->ffs;
1850         struct ffs_ep *ep         = func->eps;
1851         struct ffs_epfile *epfile = ffs->epfiles;
1852         unsigned count            = ffs->eps_count;
1853         unsigned long flags;
1854         int ret = 0;
1855
1856         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1857         while(count--) {
1858                 struct usb_endpoint_descriptor *ds;
1859                 struct usb_ss_ep_comp_descriptor *comp_desc = NULL;
1860                 int needs_comp_desc = false;
1861                 int desc_idx;
1862
1863                 if (ffs->gadget->speed == USB_SPEED_SUPER) {
1864                         desc_idx = 2;
1865                         needs_comp_desc = true;
1866                 } else if (ffs->gadget->speed == USB_SPEED_HIGH)
1867                         desc_idx = 1;
1868                 else
1869                         desc_idx = 0;
1870
1871                 /* fall-back to lower speed if desc missing for current speed */
1872                 do {
1873                         ds = ep->descs[desc_idx];
1874                 } while (!ds && --desc_idx >= 0);
1875
1876                 if (!ds) {
1877                         ret = -EINVAL;
1878                         break;
1879                 }
1880
1881                 ep->ep->driver_data = ep;
1882                 ep->ep->desc = ds;
1883
1884                 if (needs_comp_desc) {
1885                         comp_desc = (struct usb_ss_ep_comp_descriptor *)(ds +
1886                                         USB_DT_ENDPOINT_SIZE);
1887                         ep->ep->maxburst = comp_desc->bMaxBurst + 1;
1888                         ep->ep->comp_desc = comp_desc;
1889                 }
1890
1891                 ret = usb_ep_enable(ep->ep);
1892                 if (likely(!ret)) {
1893                         epfile->ep = ep;
1894                         epfile->in = usb_endpoint_dir_in(ds);
1895                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1896                 } else {
1897                         break;
1898                 }
1899
1900                 ++ep;
1901                 ++epfile;
1902         }
1903
1904         wake_up_interruptible(&ffs->wait);
1905         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1906
1907         return ret;
1908 }
1909
1910
1911 /* Parsing and building descriptors and strings *****************************/
1912
1913 /*
1914  * This validates if data pointed by data is a valid USB descriptor as
1915  * well as record how many interfaces, endpoints and strings are
1916  * required by given configuration.  Returns address after the
1917  * descriptor or NULL if data is invalid.
1918  */
1919
1920 enum ffs_entity_type {
1921         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1922 };
1923
1924 enum ffs_os_desc_type {
1925         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1926 };
1927
1928 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1929                                    u8 *valuep,
1930                                    struct usb_descriptor_header *desc,
1931                                    void *priv);
1932
1933 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1934                                     struct usb_os_desc_header *h, void *data,
1935                                     unsigned len, void *priv);
1936
1937 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1938                                            ffs_entity_callback entity,
1939                                            void *priv)
1940 {
1941         struct usb_descriptor_header *_ds = (void *)data;
1942         u8 length;
1943         int ret;
1944
1945         ENTER();
1946
1947         /* At least two bytes are required: length and type */
1948         if (len < 2) {
1949                 pr_vdebug("descriptor too short\n");
1950                 return -EINVAL;
1951         }
1952
1953         /* If we have at least as many bytes as the descriptor takes? */
1954         length = _ds->bLength;
1955         if (len < length) {
1956                 pr_vdebug("descriptor longer then available data\n");
1957                 return -EINVAL;
1958         }
1959
1960 #define __entity_check_INTERFACE(val)  1
1961 #define __entity_check_STRING(val)     (val)
1962 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1963 #define __entity(type, val) do {                                        \
1964                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1965                 if (unlikely(!__entity_check_ ##type(val))) {           \
1966                         pr_vdebug("invalid entity's value\n");          \
1967                         return -EINVAL;                                 \
1968                 }                                                       \
1969                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1970                 if (unlikely(ret < 0)) {                                \
1971                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1972                                  (val), ret);                           \
1973                         return ret;                                     \
1974                 }                                                       \
1975         } while (0)
1976
1977         /* Parse descriptor depending on type. */
1978         switch (_ds->bDescriptorType) {
1979         case USB_DT_DEVICE:
1980         case USB_DT_CONFIG:
1981         case USB_DT_STRING:
1982         case USB_DT_DEVICE_QUALIFIER:
1983                 /* function can't have any of those */
1984                 pr_vdebug("descriptor reserved for gadget: %d\n",
1985                       _ds->bDescriptorType);
1986                 return -EINVAL;
1987
1988         case USB_DT_INTERFACE: {
1989                 struct usb_interface_descriptor *ds = (void *)_ds;
1990                 pr_vdebug("interface descriptor\n");
1991                 if (length != sizeof *ds)
1992                         goto inv_length;
1993
1994                 __entity(INTERFACE, ds->bInterfaceNumber);
1995                 if (ds->iInterface)
1996                         __entity(STRING, ds->iInterface);
1997         }
1998                 break;
1999
2000         case USB_DT_ENDPOINT: {
2001                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2002                 pr_vdebug("endpoint descriptor\n");
2003                 if (length != USB_DT_ENDPOINT_SIZE &&
2004                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2005                         goto inv_length;
2006                 __entity(ENDPOINT, ds->bEndpointAddress);
2007         }
2008                 break;
2009
2010         case HID_DT_HID:
2011                 pr_vdebug("hid descriptor\n");
2012                 if (length != sizeof(struct hid_descriptor))
2013                         goto inv_length;
2014                 break;
2015
2016         case USB_DT_OTG:
2017                 if (length != sizeof(struct usb_otg_descriptor))
2018                         goto inv_length;
2019                 break;
2020
2021         case USB_DT_INTERFACE_ASSOCIATION: {
2022                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2023                 pr_vdebug("interface association descriptor\n");
2024                 if (length != sizeof *ds)
2025                         goto inv_length;
2026                 if (ds->iFunction)
2027                         __entity(STRING, ds->iFunction);
2028         }
2029                 break;
2030
2031         case USB_DT_SS_ENDPOINT_COMP:
2032                 pr_vdebug("EP SS companion descriptor\n");
2033                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2034                         goto inv_length;
2035                 break;
2036
2037         case USB_DT_OTHER_SPEED_CONFIG:
2038         case USB_DT_INTERFACE_POWER:
2039         case USB_DT_DEBUG:
2040         case USB_DT_SECURITY:
2041         case USB_DT_CS_RADIO_CONTROL:
2042                 /* TODO */
2043                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2044                 return -EINVAL;
2045
2046         default:
2047                 /* We should never be here */
2048                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2049                 return -EINVAL;
2050
2051 inv_length:
2052                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2053                           _ds->bLength, _ds->bDescriptorType);
2054                 return -EINVAL;
2055         }
2056
2057 #undef __entity
2058 #undef __entity_check_DESCRIPTOR
2059 #undef __entity_check_INTERFACE
2060 #undef __entity_check_STRING
2061 #undef __entity_check_ENDPOINT
2062
2063         return length;
2064 }
2065
2066 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2067                                      ffs_entity_callback entity, void *priv)
2068 {
2069         const unsigned _len = len;
2070         unsigned long num = 0;
2071
2072         ENTER();
2073
2074         for (;;) {
2075                 int ret;
2076
2077                 if (num == count)
2078                         data = NULL;
2079
2080                 /* Record "descriptor" entity */
2081                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2082                 if (unlikely(ret < 0)) {
2083                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2084                                  num, ret);
2085                         return ret;
2086                 }
2087
2088                 if (!data)
2089                         return _len - len;
2090
2091                 ret = ffs_do_single_desc(data, len, entity, priv);
2092                 if (unlikely(ret < 0)) {
2093                         pr_debug("%s returns %d\n", __func__, ret);
2094                         return ret;
2095                 }
2096
2097                 len -= ret;
2098                 data += ret;
2099                 ++num;
2100         }
2101 }
2102
2103 static int __ffs_data_do_entity(enum ffs_entity_type type,
2104                                 u8 *valuep, struct usb_descriptor_header *desc,
2105                                 void *priv)
2106 {
2107         struct ffs_desc_helper *helper = priv;
2108         struct usb_endpoint_descriptor *d;
2109
2110         ENTER();
2111
2112         switch (type) {
2113         case FFS_DESCRIPTOR:
2114                 break;
2115
2116         case FFS_INTERFACE:
2117                 /*
2118                  * Interfaces are indexed from zero so if we
2119                  * encountered interface "n" then there are at least
2120                  * "n+1" interfaces.
2121                  */
2122                 if (*valuep >= helper->interfaces_count)
2123                         helper->interfaces_count = *valuep + 1;
2124                 break;
2125
2126         case FFS_STRING:
2127                 /*
2128                  * Strings are indexed from 1 (0 is reserved
2129                  * for languages list)
2130                  */
2131                 if (*valuep > helper->ffs->strings_count)
2132                         helper->ffs->strings_count = *valuep;
2133                 break;
2134
2135         case FFS_ENDPOINT:
2136                 d = (void *)desc;
2137                 helper->eps_count++;
2138                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2139                         return -EINVAL;
2140                 /* Check if descriptors for any speed were already parsed */
2141                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2142                         helper->ffs->eps_addrmap[helper->eps_count] =
2143                                 d->bEndpointAddress;
2144                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2145                                 d->bEndpointAddress)
2146                         return -EINVAL;
2147                 break;
2148         }
2149
2150         return 0;
2151 }
2152
2153 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2154                                    struct usb_os_desc_header *desc)
2155 {
2156         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2157         u16 w_index = le16_to_cpu(desc->wIndex);
2158
2159         if (bcd_version != 1) {
2160                 pr_vdebug("unsupported os descriptors version: %d",
2161                           bcd_version);
2162                 return -EINVAL;
2163         }
2164         switch (w_index) {
2165         case 0x4:
2166                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2167                 break;
2168         case 0x5:
2169                 *next_type = FFS_OS_DESC_EXT_PROP;
2170                 break;
2171         default:
2172                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2173                 return -EINVAL;
2174         }
2175
2176         return sizeof(*desc);
2177 }
2178
2179 /*
2180  * Process all extended compatibility/extended property descriptors
2181  * of a feature descriptor
2182  */
2183 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2184                                               enum ffs_os_desc_type type,
2185                                               u16 feature_count,
2186                                               ffs_os_desc_callback entity,
2187                                               void *priv,
2188                                               struct usb_os_desc_header *h)
2189 {
2190         int ret;
2191         const unsigned _len = len;
2192
2193         ENTER();
2194
2195         /* loop over all ext compat/ext prop descriptors */
2196         while (feature_count--) {
2197                 ret = entity(type, h, data, len, priv);
2198                 if (unlikely(ret < 0)) {
2199                         pr_debug("bad OS descriptor, type: %d\n", type);
2200                         return ret;
2201                 }
2202                 data += ret;
2203                 len -= ret;
2204         }
2205         return _len - len;
2206 }
2207
2208 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2209 static int __must_check ffs_do_os_descs(unsigned count,
2210                                         char *data, unsigned len,
2211                                         ffs_os_desc_callback entity, void *priv)
2212 {
2213         const unsigned _len = len;
2214         unsigned long num = 0;
2215
2216         ENTER();
2217
2218         for (num = 0; num < count; ++num) {
2219                 int ret;
2220                 enum ffs_os_desc_type type;
2221                 u16 feature_count;
2222                 struct usb_os_desc_header *desc = (void *)data;
2223
2224                 if (len < sizeof(*desc))
2225                         return -EINVAL;
2226
2227                 /*
2228                  * Record "descriptor" entity.
2229                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2230                  * Move the data pointer to the beginning of extended
2231                  * compatibilities proper or extended properties proper
2232                  * portions of the data
2233                  */
2234                 if (le32_to_cpu(desc->dwLength) > len)
2235                         return -EINVAL;
2236
2237                 ret = __ffs_do_os_desc_header(&type, desc);
2238                 if (unlikely(ret < 0)) {
2239                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2240                                  num, ret);
2241                         return ret;
2242                 }
2243                 /*
2244                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2245                  */
2246                 feature_count = le16_to_cpu(desc->wCount);
2247                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2248                     (feature_count > 255 || desc->Reserved))
2249                                 return -EINVAL;
2250                 len -= ret;
2251                 data += ret;
2252
2253                 /*
2254                  * Process all function/property descriptors
2255                  * of this Feature Descriptor
2256                  */
2257                 ret = ffs_do_single_os_desc(data, len, type,
2258                                             feature_count, entity, priv, desc);
2259                 if (unlikely(ret < 0)) {
2260                         pr_debug("%s returns %d\n", __func__, ret);
2261                         return ret;
2262                 }
2263
2264                 len -= ret;
2265                 data += ret;
2266         }
2267         return _len - len;
2268 }
2269
2270 /**
2271  * Validate contents of the buffer from userspace related to OS descriptors.
2272  */
2273 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2274                                  struct usb_os_desc_header *h, void *data,
2275                                  unsigned len, void *priv)
2276 {
2277         struct ffs_data *ffs = priv;
2278         u8 length;
2279
2280         ENTER();
2281
2282         switch (type) {
2283         case FFS_OS_DESC_EXT_COMPAT: {
2284                 struct usb_ext_compat_desc *d = data;
2285                 int i;
2286
2287                 if (len < sizeof(*d) ||
2288                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2289                         return -EINVAL;
2290                 if (d->Reserved1 != 1) {
2291                         /*
2292                          * According to the spec, Reserved1 must be set to 1
2293                          * but older kernels incorrectly rejected non-zero
2294                          * values.  We fix it here to avoid returning EINVAL
2295                          * in response to values we used to accept.
2296                          */
2297                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2298                         d->Reserved1 = 1;
2299                 }
2300                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2301                         if (d->Reserved2[i])
2302                                 return -EINVAL;
2303
2304                 length = sizeof(struct usb_ext_compat_desc);
2305         }
2306                 break;
2307         case FFS_OS_DESC_EXT_PROP: {
2308                 struct usb_ext_prop_desc *d = data;
2309                 u32 type, pdl;
2310                 u16 pnl;
2311
2312                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2313                         return -EINVAL;
2314                 length = le32_to_cpu(d->dwSize);
2315                 if (len < length)
2316                         return -EINVAL;
2317                 type = le32_to_cpu(d->dwPropertyDataType);
2318                 if (type < USB_EXT_PROP_UNICODE ||
2319                     type > USB_EXT_PROP_UNICODE_MULTI) {
2320                         pr_vdebug("unsupported os descriptor property type: %d",
2321                                   type);
2322                         return -EINVAL;
2323                 }
2324                 pnl = le16_to_cpu(d->wPropertyNameLength);
2325                 if (length < 14 + pnl) {
2326                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2327                                   length, pnl, type);
2328                         return -EINVAL;
2329                 }
2330                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2331                 if (length != 14 + pnl + pdl) {
2332                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2333                                   length, pnl, pdl, type);
2334                         return -EINVAL;
2335                 }
2336                 ++ffs->ms_os_descs_ext_prop_count;
2337                 /* property name reported to the host as "WCHAR"s */
2338                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2339                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2340         }
2341                 break;
2342         default:
2343                 pr_vdebug("unknown descriptor: %d\n", type);
2344                 return -EINVAL;
2345         }
2346         return length;
2347 }
2348
2349 static int __ffs_data_got_descs(struct ffs_data *ffs,
2350                                 char *const _data, size_t len)
2351 {
2352         char *data = _data, *raw_descs;
2353         unsigned os_descs_count = 0, counts[3], flags;
2354         int ret = -EINVAL, i;
2355         struct ffs_desc_helper helper;
2356
2357         ENTER();
2358
2359         if (get_unaligned_le32(data + 4) != len)
2360                 goto error;
2361
2362         switch (get_unaligned_le32(data)) {
2363         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2364                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2365                 data += 8;
2366                 len  -= 8;
2367                 break;
2368         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2369                 flags = get_unaligned_le32(data + 8);
2370                 ffs->user_flags = flags;
2371                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2372                               FUNCTIONFS_HAS_HS_DESC |
2373                               FUNCTIONFS_HAS_SS_DESC |
2374                               FUNCTIONFS_HAS_MS_OS_DESC |
2375                               FUNCTIONFS_VIRTUAL_ADDR |
2376                               FUNCTIONFS_EVENTFD |
2377                               FUNCTIONFS_ALL_CTRL_RECIP |
2378                               FUNCTIONFS_CONFIG0_SETUP)) {
2379                         ret = -ENOSYS;
2380                         goto error;
2381                 }
2382                 data += 12;
2383                 len  -= 12;
2384                 break;
2385         default:
2386                 goto error;
2387         }
2388
2389         if (flags & FUNCTIONFS_EVENTFD) {
2390                 if (len < 4)
2391                         goto error;
2392                 ffs->ffs_eventfd =
2393                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2394                 if (IS_ERR(ffs->ffs_eventfd)) {
2395                         ret = PTR_ERR(ffs->ffs_eventfd);
2396                         ffs->ffs_eventfd = NULL;
2397                         goto error;
2398                 }
2399                 data += 4;
2400                 len  -= 4;
2401         }
2402
2403         /* Read fs_count, hs_count and ss_count (if present) */
2404         for (i = 0; i < 3; ++i) {
2405                 if (!(flags & (1 << i))) {
2406                         counts[i] = 0;
2407                 } else if (len < 4) {
2408                         goto error;
2409                 } else {
2410                         counts[i] = get_unaligned_le32(data);
2411                         data += 4;
2412                         len  -= 4;
2413                 }
2414         }
2415         if (flags & (1 << i)) {
2416                 if (len < 4) {
2417                         goto error;
2418                 }
2419                 os_descs_count = get_unaligned_le32(data);
2420                 data += 4;
2421                 len -= 4;
2422         };
2423
2424         /* Read descriptors */
2425         raw_descs = data;
2426         helper.ffs = ffs;
2427         for (i = 0; i < 3; ++i) {
2428                 if (!counts[i])
2429                         continue;
2430                 helper.interfaces_count = 0;
2431                 helper.eps_count = 0;
2432                 ret = ffs_do_descs(counts[i], data, len,
2433                                    __ffs_data_do_entity, &helper);
2434                 if (ret < 0)
2435                         goto error;
2436                 if (!ffs->eps_count && !ffs->interfaces_count) {
2437                         ffs->eps_count = helper.eps_count;
2438                         ffs->interfaces_count = helper.interfaces_count;
2439                 } else {
2440                         if (ffs->eps_count != helper.eps_count) {
2441                                 ret = -EINVAL;
2442                                 goto error;
2443                         }
2444                         if (ffs->interfaces_count != helper.interfaces_count) {
2445                                 ret = -EINVAL;
2446                                 goto error;
2447                         }
2448                 }
2449                 data += ret;
2450                 len  -= ret;
2451         }
2452         if (os_descs_count) {
2453                 ret = ffs_do_os_descs(os_descs_count, data, len,
2454                                       __ffs_data_do_os_desc, ffs);
2455                 if (ret < 0)
2456                         goto error;
2457                 data += ret;
2458                 len -= ret;
2459         }
2460
2461         if (raw_descs == data || len) {
2462                 ret = -EINVAL;
2463                 goto error;
2464         }
2465
2466         ffs->raw_descs_data     = _data;
2467         ffs->raw_descs          = raw_descs;
2468         ffs->raw_descs_length   = data - raw_descs;
2469         ffs->fs_descs_count     = counts[0];
2470         ffs->hs_descs_count     = counts[1];
2471         ffs->ss_descs_count     = counts[2];
2472         ffs->ms_os_descs_count  = os_descs_count;
2473
2474         return 0;
2475
2476 error:
2477         kfree(_data);
2478         return ret;
2479 }
2480
2481 static int __ffs_data_got_strings(struct ffs_data *ffs,
2482                                   char *const _data, size_t len)
2483 {
2484         u32 str_count, needed_count, lang_count;
2485         struct usb_gadget_strings **stringtabs, *t;
2486         const char *data = _data;
2487         struct usb_string *s;
2488
2489         ENTER();
2490
2491         if (unlikely(len < 16 ||
2492                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2493                      get_unaligned_le32(data + 4) != len))
2494                 goto error;
2495         str_count  = get_unaligned_le32(data + 8);
2496         lang_count = get_unaligned_le32(data + 12);
2497
2498         /* if one is zero the other must be zero */
2499         if (unlikely(!str_count != !lang_count))
2500                 goto error;
2501
2502         /* Do we have at least as many strings as descriptors need? */
2503         needed_count = ffs->strings_count;
2504         if (unlikely(str_count < needed_count))
2505                 goto error;
2506
2507         /*
2508          * If we don't need any strings just return and free all
2509          * memory.
2510          */
2511         if (!needed_count) {
2512                 kfree(_data);
2513                 return 0;
2514         }
2515
2516         /* Allocate everything in one chunk so there's less maintenance. */
2517         {
2518                 unsigned i = 0;
2519                 vla_group(d);
2520                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2521                         lang_count + 1);
2522                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2523                 vla_item(d, struct usb_string, strings,
2524                         lang_count*(needed_count+1));
2525
2526                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2527
2528                 if (unlikely(!vlabuf)) {
2529                         kfree(_data);
2530                         return -ENOMEM;
2531                 }
2532
2533                 /* Initialize the VLA pointers */
2534                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2535                 t = vla_ptr(vlabuf, d, stringtab);
2536                 i = lang_count;
2537                 do {
2538                         *stringtabs++ = t++;
2539                 } while (--i);
2540                 *stringtabs = NULL;
2541
2542                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2543                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2544                 t = vla_ptr(vlabuf, d, stringtab);
2545                 s = vla_ptr(vlabuf, d, strings);
2546         }
2547
2548         /* For each language */
2549         data += 16;
2550         len -= 16;
2551
2552         do { /* lang_count > 0 so we can use do-while */
2553                 unsigned needed = needed_count;
2554
2555                 if (unlikely(len < 3))
2556                         goto error_free;
2557                 t->language = get_unaligned_le16(data);
2558                 t->strings  = s;
2559                 ++t;
2560
2561                 data += 2;
2562                 len -= 2;
2563
2564                 /* For each string */
2565                 do { /* str_count > 0 so we can use do-while */
2566                         size_t length = strnlen(data, len);
2567
2568                         if (unlikely(length == len))
2569                                 goto error_free;
2570
2571                         /*
2572                          * User may provide more strings then we need,
2573                          * if that's the case we simply ignore the
2574                          * rest
2575                          */
2576                         if (likely(needed)) {
2577                                 /*
2578                                  * s->id will be set while adding
2579                                  * function to configuration so for
2580                                  * now just leave garbage here.
2581                                  */
2582                                 s->s = data;
2583                                 --needed;
2584                                 ++s;
2585                         }
2586
2587                         data += length + 1;
2588                         len -= length + 1;
2589                 } while (--str_count);
2590
2591                 s->id = 0;   /* terminator */
2592                 s->s = NULL;
2593                 ++s;
2594
2595         } while (--lang_count);
2596
2597         /* Some garbage left? */
2598         if (unlikely(len))
2599                 goto error_free;
2600
2601         /* Done! */
2602         ffs->stringtabs = stringtabs;
2603         ffs->raw_strings = _data;
2604
2605         return 0;
2606
2607 error_free:
2608         kfree(stringtabs);
2609 error:
2610         kfree(_data);
2611         return -EINVAL;
2612 }
2613
2614
2615 /* Events handling and management *******************************************/
2616
2617 static void __ffs_event_add(struct ffs_data *ffs,
2618                             enum usb_functionfs_event_type type)
2619 {
2620         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2621         int neg = 0;
2622
2623         /*
2624          * Abort any unhandled setup
2625          *
2626          * We do not need to worry about some cmpxchg() changing value
2627          * of ffs->setup_state without holding the lock because when
2628          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2629          * the source does nothing.
2630          */
2631         if (ffs->setup_state == FFS_SETUP_PENDING)
2632                 ffs->setup_state = FFS_SETUP_CANCELLED;
2633
2634         /*
2635          * Logic of this function guarantees that there are at most four pending
2636          * evens on ffs->ev.types queue.  This is important because the queue
2637          * has space for four elements only and __ffs_ep0_read_events function
2638          * depends on that limit as well.  If more event types are added, those
2639          * limits have to be revisited or guaranteed to still hold.
2640          */
2641         switch (type) {
2642         case FUNCTIONFS_RESUME:
2643                 rem_type2 = FUNCTIONFS_SUSPEND;
2644                 /* FALL THROUGH */
2645         case FUNCTIONFS_SUSPEND:
2646         case FUNCTIONFS_SETUP:
2647                 rem_type1 = type;
2648                 /* Discard all similar events */
2649                 break;
2650
2651         case FUNCTIONFS_BIND:
2652         case FUNCTIONFS_UNBIND:
2653         case FUNCTIONFS_DISABLE:
2654         case FUNCTIONFS_ENABLE:
2655                 /* Discard everything other then power management. */
2656                 rem_type1 = FUNCTIONFS_SUSPEND;
2657                 rem_type2 = FUNCTIONFS_RESUME;
2658                 neg = 1;
2659                 break;
2660
2661         default:
2662                 WARN(1, "%d: unknown event, this should not happen\n", type);
2663                 return;
2664         }
2665
2666         {
2667                 u8 *ev  = ffs->ev.types, *out = ev;
2668                 unsigned n = ffs->ev.count;
2669                 for (; n; --n, ++ev)
2670                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2671                                 *out++ = *ev;
2672                         else
2673                                 pr_vdebug("purging event %d\n", *ev);
2674                 ffs->ev.count = out - ffs->ev.types;
2675         }
2676
2677         pr_vdebug("adding event %d\n", type);
2678         ffs->ev.types[ffs->ev.count++] = type;
2679         wake_up_locked(&ffs->ev.waitq);
2680         if (ffs->ffs_eventfd)
2681                 eventfd_signal(ffs->ffs_eventfd, 1);
2682 }
2683
2684 static void ffs_event_add(struct ffs_data *ffs,
2685                           enum usb_functionfs_event_type type)
2686 {
2687         unsigned long flags;
2688         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2689         __ffs_event_add(ffs, type);
2690         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2691 }
2692
2693 /* Bind/unbind USB function hooks *******************************************/
2694
2695 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2696 {
2697         int i;
2698
2699         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2700                 if (ffs->eps_addrmap[i] == endpoint_address)
2701                         return i;
2702         return -ENOENT;
2703 }
2704
2705 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2706                                     struct usb_descriptor_header *desc,
2707                                     void *priv)
2708 {
2709         struct usb_endpoint_descriptor *ds = (void *)desc;
2710         struct ffs_function *func = priv;
2711         struct ffs_ep *ffs_ep;
2712         unsigned ep_desc_id;
2713         int idx;
2714         static const char *speed_names[] = { "full", "high", "super" };
2715
2716         if (type != FFS_DESCRIPTOR)
2717                 return 0;
2718
2719         /*
2720          * If ss_descriptors is not NULL, we are reading super speed
2721          * descriptors; if hs_descriptors is not NULL, we are reading high
2722          * speed descriptors; otherwise, we are reading full speed
2723          * descriptors.
2724          */
2725         if (func->function.ss_descriptors) {
2726                 ep_desc_id = 2;
2727                 func->function.ss_descriptors[(long)valuep] = desc;
2728         } else if (func->function.hs_descriptors) {
2729                 ep_desc_id = 1;
2730                 func->function.hs_descriptors[(long)valuep] = desc;
2731         } else {
2732                 ep_desc_id = 0;
2733                 func->function.fs_descriptors[(long)valuep]    = desc;
2734         }
2735
2736         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2737                 return 0;
2738
2739         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2740         if (idx < 0)
2741                 return idx;
2742
2743         ffs_ep = func->eps + idx;
2744
2745         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2746                 pr_err("two %sspeed descriptors for EP %d\n",
2747                           speed_names[ep_desc_id],
2748                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2749                 return -EINVAL;
2750         }
2751         ffs_ep->descs[ep_desc_id] = ds;
2752
2753         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2754         if (ffs_ep->ep) {
2755                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2756                 if (!ds->wMaxPacketSize)
2757                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2758         } else {
2759                 struct usb_request *req;
2760                 struct usb_ep *ep;
2761                 u8 bEndpointAddress;
2762
2763                 /*
2764                  * We back up bEndpointAddress because autoconfig overwrites
2765                  * it with physical endpoint address.
2766                  */
2767                 bEndpointAddress = ds->bEndpointAddress;
2768                 pr_vdebug("autoconfig\n");
2769                 ep = usb_ep_autoconfig(func->gadget, ds);
2770                 if (unlikely(!ep))
2771                         return -ENOTSUPP;
2772                 ep->driver_data = func->eps + idx;
2773
2774                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2775                 if (unlikely(!req))
2776                         return -ENOMEM;
2777
2778                 ffs_ep->ep  = ep;
2779                 ffs_ep->req = req;
2780                 func->eps_revmap[ds->bEndpointAddress &
2781                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2782                 /*
2783                  * If we use virtual address mapping, we restore
2784                  * original bEndpointAddress value.
2785                  */
2786                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2787                         ds->bEndpointAddress = bEndpointAddress;
2788         }
2789         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2790
2791         return 0;
2792 }
2793
2794 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2795                                    struct usb_descriptor_header *desc,
2796                                    void *priv)
2797 {
2798         struct ffs_function *func = priv;
2799         unsigned idx;
2800         u8 newValue;
2801
2802         switch (type) {
2803         default:
2804         case FFS_DESCRIPTOR:
2805                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2806                 return 0;
2807
2808         case FFS_INTERFACE:
2809                 idx = *valuep;
2810                 if (func->interfaces_nums[idx] < 0) {
2811                         int id = usb_interface_id(func->conf, &func->function);
2812                         if (unlikely(id < 0))
2813                                 return id;
2814                         func->interfaces_nums[idx] = id;
2815                 }
2816                 newValue = func->interfaces_nums[idx];
2817                 break;
2818
2819         case FFS_STRING:
2820                 /* String' IDs are allocated when fsf_data is bound to cdev */
2821                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2822                 break;
2823
2824         case FFS_ENDPOINT:
2825                 /*
2826                  * USB_DT_ENDPOINT are handled in
2827                  * __ffs_func_bind_do_descs().
2828                  */
2829                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2830                         return 0;
2831
2832                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2833                 if (unlikely(!func->eps[idx].ep))
2834                         return -EINVAL;
2835
2836                 {
2837                         struct usb_endpoint_descriptor **descs;
2838                         descs = func->eps[idx].descs;
2839                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2840                 }
2841                 break;
2842         }
2843
2844         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2845         *valuep = newValue;
2846         return 0;
2847 }
2848
2849 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2850                                       struct usb_os_desc_header *h, void *data,
2851                                       unsigned len, void *priv)
2852 {
2853         struct ffs_function *func = priv;
2854         u8 length = 0;
2855
2856         switch (type) {
2857         case FFS_OS_DESC_EXT_COMPAT: {
2858                 struct usb_ext_compat_desc *desc = data;
2859                 struct usb_os_desc_table *t;
2860
2861                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2862                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2863                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2864                        ARRAY_SIZE(desc->CompatibleID) +
2865                        ARRAY_SIZE(desc->SubCompatibleID));
2866                 length = sizeof(*desc);
2867         }
2868                 break;
2869         case FFS_OS_DESC_EXT_PROP: {
2870                 struct usb_ext_prop_desc *desc = data;
2871                 struct usb_os_desc_table *t;
2872                 struct usb_os_desc_ext_prop *ext_prop;
2873                 char *ext_prop_name;
2874                 char *ext_prop_data;
2875
2876                 t = &func->function.os_desc_table[h->interface];
2877                 t->if_id = func->interfaces_nums[h->interface];
2878
2879                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2880                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2881
2882                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2883                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2884                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2885                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2886                 length = ext_prop->name_len + ext_prop->data_len + 14;
2887
2888                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2889                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2890                         ext_prop->name_len;
2891
2892                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2893                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2894                         ext_prop->data_len;
2895                 memcpy(ext_prop_data,
2896                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2897                        ext_prop->data_len);
2898                 /* unicode data reported to the host as "WCHAR"s */
2899                 switch (ext_prop->type) {
2900                 case USB_EXT_PROP_UNICODE:
2901                 case USB_EXT_PROP_UNICODE_ENV:
2902                 case USB_EXT_PROP_UNICODE_LINK:
2903                 case USB_EXT_PROP_UNICODE_MULTI:
2904                         ext_prop->data_len *= 2;
2905                         break;
2906                 }
2907                 ext_prop->data = ext_prop_data;
2908
2909                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2910                        ext_prop->name_len);
2911                 /* property name reported to the host as "WCHAR"s */
2912                 ext_prop->name_len *= 2;
2913                 ext_prop->name = ext_prop_name;
2914
2915                 t->os_desc->ext_prop_len +=
2916                         ext_prop->name_len + ext_prop->data_len + 14;
2917                 ++t->os_desc->ext_prop_count;
2918                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2919         }
2920                 break;
2921         default:
2922                 pr_vdebug("unknown descriptor: %d\n", type);
2923         }
2924
2925         return length;
2926 }
2927
2928 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2929                                                 struct usb_configuration *c)
2930 {
2931         struct ffs_function *func = ffs_func_from_usb(f);
2932         struct f_fs_opts *ffs_opts =
2933                 container_of(f->fi, struct f_fs_opts, func_inst);
2934         int ret;
2935
2936         ENTER();
2937
2938         /*
2939          * Legacy gadget triggers binding in functionfs_ready_callback,
2940          * which already uses locking; taking the same lock here would
2941          * cause a deadlock.
2942          *
2943          * Configfs-enabled gadgets however do need ffs_dev_lock.
2944          */
2945         if (!ffs_opts->no_configfs)
2946                 ffs_dev_lock();
2947         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2948         func->ffs = ffs_opts->dev->ffs_data;
2949         if (!ffs_opts->no_configfs)
2950                 ffs_dev_unlock();
2951         if (ret)
2952                 return ERR_PTR(ret);
2953
2954         func->conf = c;
2955         func->gadget = c->cdev->gadget;
2956
2957         /*
2958          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2959          * configurations are bound in sequence with list_for_each_entry,
2960          * in each configuration its functions are bound in sequence
2961          * with list_for_each_entry, so we assume no race condition
2962          * with regard to ffs_opts->bound access
2963          */
2964         if (!ffs_opts->refcnt) {
2965                 ret = functionfs_bind(func->ffs, c->cdev);
2966                 if (ret)
2967                         return ERR_PTR(ret);
2968         }
2969         ffs_opts->refcnt++;
2970         func->function.strings = func->ffs->stringtabs;
2971
2972         return ffs_opts;
2973 }
2974
2975 static int _ffs_func_bind(struct usb_configuration *c,
2976                           struct usb_function *f)
2977 {
2978         struct ffs_function *func = ffs_func_from_usb(f);
2979         struct ffs_data *ffs = func->ffs;
2980
2981         const int full = !!func->ffs->fs_descs_count;
2982         const int high = gadget_is_dualspeed(func->gadget) &&
2983                 func->ffs->hs_descs_count;
2984         const int super = gadget_is_superspeed(func->gadget) &&
2985                 func->ffs->ss_descs_count;
2986
2987         int fs_len, hs_len, ss_len, ret, i;
2988         struct ffs_ep *eps_ptr;
2989
2990         /* Make it a single chunk, less management later on */
2991         vla_group(d);
2992         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2993         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2994                 full ? ffs->fs_descs_count + 1 : 0);
2995         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2996                 high ? ffs->hs_descs_count + 1 : 0);
2997         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2998                 super ? ffs->ss_descs_count + 1 : 0);
2999         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3000         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3001                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3002         vla_item_with_sz(d, char[16], ext_compat,
3003                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3004         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3005                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3006         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3007                          ffs->ms_os_descs_ext_prop_count);
3008         vla_item_with_sz(d, char, ext_prop_name,
3009                          ffs->ms_os_descs_ext_prop_name_len);
3010         vla_item_with_sz(d, char, ext_prop_data,
3011                          ffs->ms_os_descs_ext_prop_data_len);
3012         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3013         char *vlabuf;
3014
3015         ENTER();
3016
3017         /* Has descriptors only for speeds gadget does not support */
3018         if (unlikely(!(full | high | super)))
3019                 return -ENOTSUPP;
3020
3021         /* Allocate a single chunk, less management later on */
3022         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3023         if (unlikely(!vlabuf))
3024                 return -ENOMEM;
3025
3026         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3027         ffs->ms_os_descs_ext_prop_name_avail =
3028                 vla_ptr(vlabuf, d, ext_prop_name);
3029         ffs->ms_os_descs_ext_prop_data_avail =
3030                 vla_ptr(vlabuf, d, ext_prop_data);
3031
3032         /* Copy descriptors  */
3033         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3034                ffs->raw_descs_length);
3035
3036         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3037         eps_ptr = vla_ptr(vlabuf, d, eps);
3038         for (i = 0; i < ffs->eps_count; i++)
3039                 eps_ptr[i].num = -1;
3040
3041         /* Save pointers
3042          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3043         */
3044         func->eps             = vla_ptr(vlabuf, d, eps);
3045         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3046
3047         /*
3048          * Go through all the endpoint descriptors and allocate
3049          * endpoints first, so that later we can rewrite the endpoint
3050          * numbers without worrying that it may be described later on.
3051          */
3052         if (likely(full)) {
3053                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3054                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3055                                       vla_ptr(vlabuf, d, raw_descs),
3056                                       d_raw_descs__sz,
3057                                       __ffs_func_bind_do_descs, func);
3058                 if (unlikely(fs_len < 0)) {
3059                         ret = fs_len;
3060                         goto error;
3061                 }
3062         } else {
3063                 fs_len = 0;
3064         }
3065
3066         if (likely(high)) {
3067                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3068                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3069                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3070                                       d_raw_descs__sz - fs_len,
3071                                       __ffs_func_bind_do_descs, func);
3072                 if (unlikely(hs_len < 0)) {
3073                         ret = hs_len;
3074                         goto error;
3075                 }
3076         } else {
3077                 hs_len = 0;
3078         }
3079
3080         if (likely(super)) {
3081                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3082                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3083                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3084                                 d_raw_descs__sz - fs_len - hs_len,
3085                                 __ffs_func_bind_do_descs, func);
3086                 if (unlikely(ss_len < 0)) {
3087                         ret = ss_len;
3088                         goto error;
3089                 }
3090         } else {
3091                 ss_len = 0;
3092         }
3093
3094         /*
3095          * Now handle interface numbers allocation and interface and
3096          * endpoint numbers rewriting.  We can do that in one go
3097          * now.
3098          */
3099         ret = ffs_do_descs(ffs->fs_descs_count +
3100                            (high ? ffs->hs_descs_count : 0) +
3101                            (super ? ffs->ss_descs_count : 0),
3102                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3103                            __ffs_func_bind_do_nums, func);
3104         if (unlikely(ret < 0))
3105                 goto error;
3106
3107         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3108         if (c->cdev->use_os_string) {
3109                 for (i = 0; i < ffs->interfaces_count; ++i) {
3110                         struct usb_os_desc *desc;
3111
3112                         desc = func->function.os_desc_table[i].os_desc =
3113                                 vla_ptr(vlabuf, d, os_desc) +
3114                                 i * sizeof(struct usb_os_desc);
3115                         desc->ext_compat_id =
3116                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3117                         INIT_LIST_HEAD(&desc->ext_prop);
3118                 }
3119                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3120                                       vla_ptr(vlabuf, d, raw_descs) +
3121                                       fs_len + hs_len + ss_len,
3122                                       d_raw_descs__sz - fs_len - hs_len -
3123                                       ss_len,
3124                                       __ffs_func_bind_do_os_desc, func);
3125                 if (unlikely(ret < 0))
3126                         goto error;
3127         }
3128         func->function.os_desc_n =
3129                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3130
3131         /* And we're done */
3132         ffs_event_add(ffs, FUNCTIONFS_BIND);
3133         return 0;
3134
3135 error:
3136         /* XXX Do we need to release all claimed endpoints here? */
3137         return ret;
3138 }
3139
3140 static int ffs_func_bind(struct usb_configuration *c,
3141                          struct usb_function *f)
3142 {
3143         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3144         struct ffs_function *func = ffs_func_from_usb(f);
3145         int ret;
3146
3147         if (IS_ERR(ffs_opts))
3148                 return PTR_ERR(ffs_opts);
3149
3150         ret = _ffs_func_bind(c, f);
3151         if (ret && !--ffs_opts->refcnt)
3152                 functionfs_unbind(func->ffs);
3153
3154         return ret;
3155 }
3156
3157
3158 /* Other USB function hooks *************************************************/
3159
3160 static void ffs_reset_work(struct work_struct *work)
3161 {
3162         struct ffs_data *ffs = container_of(work,
3163                 struct ffs_data, reset_work);
3164         ffs_data_reset(ffs);
3165 }
3166
3167 static int ffs_func_set_alt(struct usb_function *f,
3168                             unsigned interface, unsigned alt)
3169 {
3170         struct ffs_function *func = ffs_func_from_usb(f);
3171         struct ffs_data *ffs = func->ffs;
3172         int ret = 0, intf;
3173
3174         if (alt != (unsigned)-1) {
3175                 intf = ffs_func_revmap_intf(func, interface);
3176                 if (unlikely(intf < 0))
3177                         return intf;
3178         }
3179
3180         if (ffs->func)
3181                 ffs_func_eps_disable(ffs->func);
3182
3183         if (ffs->state == FFS_DEACTIVATED) {
3184                 ffs->state = FFS_CLOSING;
3185                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3186                 schedule_work(&ffs->reset_work);
3187                 return -ENODEV;
3188         }
3189
3190         if (ffs->state != FFS_ACTIVE)
3191                 return -ENODEV;
3192
3193         if (alt == (unsigned)-1) {
3194                 ffs->func = NULL;
3195                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3196                 return 0;
3197         }
3198
3199         ffs->func = func;
3200         ret = ffs_func_eps_enable(func);
3201         if (likely(ret >= 0))
3202                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3203         return ret;
3204 }
3205
3206 static void ffs_func_disable(struct usb_function *f)
3207 {
3208         ffs_func_set_alt(f, 0, (unsigned)-1);
3209 }
3210
3211 static int ffs_func_setup(struct usb_function *f,
3212                           const struct usb_ctrlrequest *creq)
3213 {
3214         struct ffs_function *func = ffs_func_from_usb(f);
3215         struct ffs_data *ffs = func->ffs;
3216         unsigned long flags;
3217         int ret;
3218
3219         ENTER();
3220
3221         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3222         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3223         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3224         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3225         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3226
3227         /*
3228          * Most requests directed to interface go through here
3229          * (notable exceptions are set/get interface) so we need to
3230          * handle them.  All other either handled by composite or
3231          * passed to usb_configuration->setup() (if one is set).  No
3232          * matter, we will handle requests directed to endpoint here
3233          * as well (as it's straightforward).  Other request recipient
3234          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3235          * is being used.
3236          */
3237         if (ffs->state != FFS_ACTIVE)
3238                 return -ENODEV;
3239
3240         switch (creq->bRequestType & USB_RECIP_MASK) {
3241         case USB_RECIP_INTERFACE:
3242                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3243                 if (unlikely(ret < 0))
3244                         return ret;
3245                 break;
3246
3247         case USB_RECIP_ENDPOINT:
3248                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3249                 if (unlikely(ret < 0))
3250                         return ret;
3251                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3252                         ret = func->ffs->eps_addrmap[ret];
3253                 break;
3254
3255         default:
3256                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3257                         ret = le16_to_cpu(creq->wIndex);
3258                 else
3259                         return -EOPNOTSUPP;
3260         }
3261
3262         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3263         ffs->ev.setup = *creq;
3264         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3265         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3266         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3267
3268         return 0;
3269 }
3270
3271 static bool ffs_func_req_match(struct usb_function *f,
3272                                const struct usb_ctrlrequest *creq,
3273                                bool config0)
3274 {
3275         struct ffs_function *func = ffs_func_from_usb(f);
3276
3277         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3278                 return false;
3279
3280         switch (creq->bRequestType & USB_RECIP_MASK) {
3281         case USB_RECIP_INTERFACE:
3282                 return (ffs_func_revmap_intf(func,
3283                                              le16_to_cpu(creq->wIndex)) >= 0);
3284         case USB_RECIP_ENDPOINT:
3285                 return (ffs_func_revmap_ep(func,
3286                                            le16_to_cpu(creq->wIndex)) >= 0);
3287         default:
3288                 return (bool) (func->ffs->user_flags &
3289                                FUNCTIONFS_ALL_CTRL_RECIP);
3290         }
3291 }
3292
3293 static void ffs_func_suspend(struct usb_function *f)
3294 {
3295         ENTER();
3296         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3297 }
3298
3299 static void ffs_func_resume(struct usb_function *f)
3300 {
3301         ENTER();
3302         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3303 }
3304
3305
3306 /* Endpoint and interface numbers reverse mapping ***************************/
3307
3308 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3309 {
3310         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3311         return num ? num : -EDOM;
3312 }
3313
3314 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3315 {
3316         short *nums = func->interfaces_nums;
3317         unsigned count = func->ffs->interfaces_count;
3318
3319         for (; count; --count, ++nums) {
3320                 if (*nums >= 0 && *nums == intf)
3321                         return nums - func->interfaces_nums;
3322         }
3323
3324         return -EDOM;
3325 }
3326
3327
3328 /* Devices management *******************************************************/
3329
3330 static LIST_HEAD(ffs_devices);
3331
3332 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3333 {
3334         struct ffs_dev *dev;
3335
3336         if (!name)
3337                 return NULL;
3338
3339         list_for_each_entry(dev, &ffs_devices, entry) {
3340                 if (strcmp(dev->name, name) == 0)
3341                         return dev;
3342         }
3343
3344         return NULL;
3345 }
3346
3347 /*
3348  * ffs_lock must be taken by the caller of this function
3349  */
3350 static struct ffs_dev *_ffs_get_single_dev(void)
3351 {
3352         struct ffs_dev *dev;
3353
3354         if (list_is_singular(&ffs_devices)) {
3355                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3356                 if (dev->single)
3357                         return dev;
3358         }
3359
3360         return NULL;
3361 }
3362
3363 /*
3364  * ffs_lock must be taken by the caller of this function
3365  */
3366 static struct ffs_dev *_ffs_find_dev(const char *name)
3367 {
3368         struct ffs_dev *dev;
3369
3370         dev = _ffs_get_single_dev();
3371         if (dev)
3372                 return dev;
3373
3374         return _ffs_do_find_dev(name);
3375 }
3376
3377 /* Configfs support *********************************************************/
3378
3379 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3380 {
3381         return container_of(to_config_group(item), struct f_fs_opts,
3382                             func_inst.group);
3383 }
3384
3385 static void ffs_attr_release(struct config_item *item)
3386 {
3387         struct f_fs_opts *opts = to_ffs_opts(item);
3388
3389         usb_put_function_instance(&opts->func_inst);
3390 }
3391
3392 static struct configfs_item_operations ffs_item_ops = {
3393         .release        = ffs_attr_release,
3394 };
3395
3396 static const struct config_item_type ffs_func_type = {
3397         .ct_item_ops    = &ffs_item_ops,
3398         .ct_owner       = THIS_MODULE,
3399 };
3400
3401
3402 /* Function registration interface ******************************************/
3403
3404 static void ffs_free_inst(struct usb_function_instance *f)
3405 {
3406         struct f_fs_opts *opts;
3407
3408         opts = to_f_fs_opts(f);
3409         ffs_dev_lock();
3410         _ffs_free_dev(opts->dev);
3411         ffs_dev_unlock();
3412         kfree(opts);
3413 }
3414
3415 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3416 {
3417         if (strlen(name) >= FIELD_SIZEOF(struct ffs_dev, name))
3418                 return -ENAMETOOLONG;
3419         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3420 }
3421
3422 static struct usb_function_instance *ffs_alloc_inst(void)
3423 {
3424         struct f_fs_opts *opts;
3425         struct ffs_dev *dev;
3426
3427         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3428         if (!opts)
3429                 return ERR_PTR(-ENOMEM);
3430
3431         opts->func_inst.set_inst_name = ffs_set_inst_name;
3432         opts->func_inst.free_func_inst = ffs_free_inst;
3433         ffs_dev_lock();
3434         dev = _ffs_alloc_dev();
3435         ffs_dev_unlock();
3436         if (IS_ERR(dev)) {
3437                 kfree(opts);
3438                 return ERR_CAST(dev);
3439         }
3440         opts->dev = dev;
3441         dev->opts = opts;
3442
3443         config_group_init_type_name(&opts->func_inst.group, "",
3444                                     &ffs_func_type);
3445         return &opts->func_inst;
3446 }
3447
3448 static void ffs_free(struct usb_function *f)
3449 {
3450         kfree(ffs_func_from_usb(f));
3451 }
3452
3453 static void ffs_func_unbind(struct usb_configuration *c,
3454                             struct usb_function *f)
3455 {
3456         struct ffs_function *func = ffs_func_from_usb(f);
3457         struct ffs_data *ffs = func->ffs;
3458         struct f_fs_opts *opts =
3459                 container_of(f->fi, struct f_fs_opts, func_inst);
3460         struct ffs_ep *ep = func->eps;
3461         unsigned count = ffs->eps_count;
3462         unsigned long flags;
3463
3464         ENTER();
3465         if (ffs->func == func) {
3466                 ffs_func_eps_disable(func);
3467                 ffs->func = NULL;
3468         }
3469
3470         if (!--opts->refcnt)
3471                 functionfs_unbind(ffs);
3472
3473         /* cleanup after autoconfig */
3474         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3475         while (count--) {
3476                 if (ep->ep && ep->req)
3477                         usb_ep_free_request(ep->ep, ep->req);
3478                 ep->req = NULL;
3479                 ++ep;
3480         }
3481         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3482         kfree(func->eps);
3483         func->eps = NULL;
3484         /*
3485          * eps, descriptors and interfaces_nums are allocated in the
3486          * same chunk so only one free is required.
3487          */
3488         func->function.fs_descriptors = NULL;
3489         func->function.hs_descriptors = NULL;
3490         func->function.ss_descriptors = NULL;
3491         func->interfaces_nums = NULL;
3492
3493         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3494 }
3495
3496 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3497 {
3498         struct ffs_function *func;
3499
3500         ENTER();
3501
3502         func = kzalloc(sizeof(*func), GFP_KERNEL);
3503         if (unlikely(!func))
3504                 return ERR_PTR(-ENOMEM);
3505
3506         func->function.name    = "Function FS Gadget";
3507
3508         func->function.bind    = ffs_func_bind;
3509         func->function.unbind  = ffs_func_unbind;
3510         func->function.set_alt = ffs_func_set_alt;
3511         func->function.disable = ffs_func_disable;
3512         func->function.setup   = ffs_func_setup;
3513         func->function.req_match = ffs_func_req_match;
3514         func->function.suspend = ffs_func_suspend;
3515         func->function.resume  = ffs_func_resume;
3516         func->function.free_func = ffs_free;
3517
3518         return &func->function;
3519 }
3520
3521 /*
3522  * ffs_lock must be taken by the caller of this function
3523  */
3524 static struct ffs_dev *_ffs_alloc_dev(void)
3525 {
3526         struct ffs_dev *dev;
3527         int ret;
3528
3529         if (_ffs_get_single_dev())
3530                         return ERR_PTR(-EBUSY);
3531
3532         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3533         if (!dev)
3534                 return ERR_PTR(-ENOMEM);
3535
3536         if (list_empty(&ffs_devices)) {
3537                 ret = functionfs_init();
3538                 if (ret) {
3539                         kfree(dev);
3540                         return ERR_PTR(ret);
3541                 }
3542         }
3543
3544         list_add(&dev->entry, &ffs_devices);
3545
3546         return dev;
3547 }
3548
3549 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3550 {
3551         struct ffs_dev *existing;
3552         int ret = 0;
3553
3554         ffs_dev_lock();
3555
3556         existing = _ffs_do_find_dev(name);
3557         if (!existing)
3558                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3559         else if (existing != dev)
3560                 ret = -EBUSY;
3561
3562         ffs_dev_unlock();
3563
3564         return ret;
3565 }
3566 EXPORT_SYMBOL_GPL(ffs_name_dev);
3567
3568 int ffs_single_dev(struct ffs_dev *dev)
3569 {
3570         int ret;
3571
3572         ret = 0;
3573         ffs_dev_lock();
3574
3575         if (!list_is_singular(&ffs_devices))
3576                 ret = -EBUSY;
3577         else
3578                 dev->single = true;
3579
3580         ffs_dev_unlock();
3581         return ret;
3582 }
3583 EXPORT_SYMBOL_GPL(ffs_single_dev);
3584
3585 /*
3586  * ffs_lock must be taken by the caller of this function
3587  */
3588 static void _ffs_free_dev(struct ffs_dev *dev)
3589 {
3590         list_del(&dev->entry);
3591
3592         /* Clear the private_data pointer to stop incorrect dev access */
3593         if (dev->ffs_data)
3594                 dev->ffs_data->private_data = NULL;
3595
3596         kfree(dev);
3597         if (list_empty(&ffs_devices))
3598                 functionfs_cleanup();
3599 }
3600
3601 static void *ffs_acquire_dev(const char *dev_name)
3602 {
3603         struct ffs_dev *ffs_dev;
3604
3605         ENTER();
3606         ffs_dev_lock();
3607
3608         ffs_dev = _ffs_find_dev(dev_name);
3609         if (!ffs_dev)
3610                 ffs_dev = ERR_PTR(-ENOENT);
3611         else if (ffs_dev->mounted)
3612                 ffs_dev = ERR_PTR(-EBUSY);
3613         else if (ffs_dev->ffs_acquire_dev_callback &&
3614             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3615                 ffs_dev = ERR_PTR(-ENOENT);
3616         else
3617                 ffs_dev->mounted = true;
3618
3619         ffs_dev_unlock();
3620         return ffs_dev;
3621 }
3622
3623 static void ffs_release_dev(struct ffs_data *ffs_data)
3624 {
3625         struct ffs_dev *ffs_dev;
3626
3627         ENTER();
3628         ffs_dev_lock();
3629
3630         ffs_dev = ffs_data->private_data;
3631         if (ffs_dev) {
3632                 ffs_dev->mounted = false;
3633
3634                 if (ffs_dev->ffs_release_dev_callback)
3635                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3636         }
3637
3638         ffs_dev_unlock();
3639 }
3640
3641 static int ffs_ready(struct ffs_data *ffs)
3642 {
3643         struct ffs_dev *ffs_obj;
3644         int ret = 0;
3645
3646         ENTER();
3647         ffs_dev_lock();
3648
3649         ffs_obj = ffs->private_data;
3650         if (!ffs_obj) {
3651                 ret = -EINVAL;
3652                 goto done;
3653         }
3654         if (WARN_ON(ffs_obj->desc_ready)) {
3655                 ret = -EBUSY;
3656                 goto done;
3657         }
3658
3659         ffs_obj->desc_ready = true;
3660         ffs_obj->ffs_data = ffs;
3661
3662         if (ffs_obj->ffs_ready_callback) {
3663                 ret = ffs_obj->ffs_ready_callback(ffs);
3664                 if (ret)
3665                         goto done;
3666         }
3667
3668         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3669 done:
3670         ffs_dev_unlock();
3671         return ret;
3672 }
3673
3674 static void ffs_closed(struct ffs_data *ffs)
3675 {
3676         struct ffs_dev *ffs_obj;
3677         struct f_fs_opts *opts;
3678         struct config_item *ci;
3679
3680         ENTER();
3681         ffs_dev_lock();
3682
3683         ffs_obj = ffs->private_data;
3684         if (!ffs_obj)
3685                 goto done;
3686
3687         ffs_obj->desc_ready = false;
3688         ffs_obj->ffs_data = NULL;
3689
3690         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3691             ffs_obj->ffs_closed_callback)
3692                 ffs_obj->ffs_closed_callback(ffs);
3693
3694         if (ffs_obj->opts)
3695                 opts = ffs_obj->opts;
3696         else
3697                 goto done;
3698
3699         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3700             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3701                 goto done;
3702
3703         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3704         ffs_dev_unlock();
3705
3706         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3707                 unregister_gadget_item(ci);
3708         return;
3709 done:
3710         ffs_dev_unlock();
3711 }
3712
3713 /* Misc helper functions ****************************************************/
3714
3715 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3716 {
3717         return nonblock
3718                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3719                 : mutex_lock_interruptible(mutex);
3720 }
3721
3722 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3723 {
3724         char *data;
3725
3726         if (unlikely(!len))
3727                 return NULL;
3728
3729         data = kmalloc(len, GFP_KERNEL);
3730         if (unlikely(!data))
3731                 return ERR_PTR(-ENOMEM);
3732
3733         if (unlikely(copy_from_user(data, buf, len))) {
3734                 kfree(data);
3735                 return ERR_PTR(-EFAULT);
3736         }
3737
3738         pr_vdebug("Buffer from user space:\n");
3739         ffs_dump_mem("", data, len);
3740
3741         return data;
3742 }
3743
3744 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3745 MODULE_LICENSE("GPL");
3746 MODULE_AUTHOR("Michal Nazarewicz");