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 int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data);
 247 static void ffs_release_dev(struct ffs_dev *ffs_dev);
 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 stream_open(inode, file);
 611 }
 612
 613 static int ffs_ep0_release(struct inode *inode, struct file *file)
 614 {
 615         struct ffs_data *ffs = file->private_data;
 616
 617         ENTER();
 618
 619         ffs_data_closed(ffs);
 620
 621         return 0;
 622 }
 623
 624 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 625 {
 626         struct ffs_data *ffs = file->private_data;
 627         struct usb_gadget *gadget = ffs->gadget;
 628         long ret;
 629
 630         ENTER();
 631
 632         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 633                 struct ffs_function *func = ffs->func;
 634                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 635         } else if (gadget && gadget->ops->ioctl) {
 636                 ret = gadget->ops->ioctl(gadget, code, value);
 637         } else {
 638                 ret = -ENOTTY;
 639         }
 640
 641         return ret;
 642 }
 643
 644 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 645 {
 646         struct ffs_data *ffs = file->private_data;
 647         __poll_t mask = EPOLLWRNORM;
 648         int ret;
 649
 650         poll_wait(file, &ffs->ev.waitq, wait);
 651
 652         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 653         if (unlikely(ret < 0))
 654                 return mask;
 655
 656         switch (ffs->state) {
 657         case FFS_READ_DESCRIPTORS:
 658         case FFS_READ_STRINGS:
 659                 mask |= EPOLLOUT;
 660                 break;
 661
 662         case FFS_ACTIVE:
 663                 switch (ffs->setup_state) {
 664                 case FFS_NO_SETUP:
 665                         if (ffs->ev.count)
 666                                 mask |= EPOLLIN;
 667                         break;
 668
 669                 case FFS_SETUP_PENDING:
 670                 case FFS_SETUP_CANCELLED:
 671                         mask |= (EPOLLIN | EPOLLOUT);
 672                         break;
 673                 }
 674         case FFS_CLOSING:
 675                 break;
 676         case FFS_DEACTIVATED:
 677                 break;
 678         }
 679
 680         mutex_unlock(&ffs->mutex);
 681
 682         return mask;
 683 }
 684
 685 static const struct file_operations ffs_ep0_operations = {
 686         .llseek =       no_llseek,
 687
 688         .open =         ffs_ep0_open,
 689         .write =        ffs_ep0_write,
 690         .read =         ffs_ep0_read,
 691         .release =      ffs_ep0_release,
 692         .unlocked_ioctl =       ffs_ep0_ioctl,
 693         .poll =         ffs_ep0_poll,
 694 };
 695
 696
 697 /* "Normal" endpoints operations ********************************************/
 698
 699 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 700 {
 701         ENTER();
 702         if (likely(req->context)) {
 703                 struct ffs_ep *ep = _ep->driver_data;
 704                 ep->status = req->status ? req->status : req->actual;
 705                 complete(req->context);
 706         }
 707 }
 708
 709 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 710 {
 711         ssize_t ret = copy_to_iter(data, data_len, iter);
 712         if (likely(ret == data_len))
 713                 return ret;
 714
 715         if (unlikely(iov_iter_count(iter)))
 716                 return -EFAULT;
 717
 718         /*
 719          * Dear user space developer!
 720          *
 721          * TL;DR: To stop getting below error message in your kernel log, change
 722          * user space code using functionfs to align read buffers to a max
 723          * packet size.
 724          *
 725          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 726          * packet size.  When unaligned buffer is passed to functionfs, it
 727          * internally uses a larger, aligned buffer so that such UDCs are happy.
 728          *
 729          * Unfortunately, this means that host may send more data than was
 730          * requested in read(2) system call.  f_fs doesn’t know what to do with
 731          * that excess data so it simply drops it.
 732          *
 733          * Was the buffer aligned in the first place, no such problem would
 734          * happen.
 735          *
 736          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 737          * by splitting a request into multiple parts.  This splitting may still
 738          * be a problem though so it’s likely best to align the buffer
 739          * regardless of it being AIO or not..
 740          *
 741          * This only affects OUT endpoints, i.e. reading data with a read(2),
 742          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 743          * affected.
 744          */
 745         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 746                "Align read buffer size to max packet size to avoid the problem.\n",
 747                data_len, ret);
 748
 749         return ret;
 750 }
 751
 752 static void ffs_user_copy_worker(struct work_struct *work)
 753 {
 754         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 755                                                    work);
 756         int ret = io_data->req->status ? io_data->req->status :
 757                                          io_data->req->actual;
 758         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 759
 760         if (io_data->read && ret > 0) {
 761                 mm_segment_t oldfs = get_fs();
 762
 763                 set_fs(USER_DS);
 764                 use_mm(io_data->mm);
 765                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 766                 unuse_mm(io_data->mm);
 767                 set_fs(oldfs);
 768         }
 769
 770         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 771
 772         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 773                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 774
 775         usb_ep_free_request(io_data->ep, io_data->req);
 776
 777         if (io_data->read)
 778                 kfree(io_data->to_free);
 779         kfree(io_data->buf);
 780         kfree(io_data);
 781 }
 782
 783 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 784                                          struct usb_request *req)
 785 {
 786         struct ffs_io_data *io_data = req->context;
 787         struct ffs_data *ffs = io_data->ffs;
 788
 789         ENTER();
 790
 791         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 792         queue_work(ffs->io_completion_wq, &io_data->work);
 793 }
 794
 795 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 796 {
 797         /*
 798          * See comment in struct ffs_epfile for full read_buffer pointer
 799          * synchronisation story.
 800          */
 801         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 802         if (buf && buf != READ_BUFFER_DROP)
 803                 kfree(buf);
 804 }
 805
 806 /* Assumes epfile->mutex is held. */
 807 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 808                                           struct iov_iter *iter)
 809 {
 810         /*
 811          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 812          * the buffer while we are using it.  See comment in struct ffs_epfile
 813          * for full read_buffer pointer synchronisation story.
 814          */
 815         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 816         ssize_t ret;
 817         if (!buf || buf == READ_BUFFER_DROP)
 818                 return 0;
 819
 820         ret = copy_to_iter(buf->data, buf->length, iter);
 821         if (buf->length == ret) {
 822                 kfree(buf);
 823                 return ret;
 824         }
 825
 826         if (unlikely(iov_iter_count(iter))) {
 827                 ret = -EFAULT;
 828         } else {
 829                 buf->length -= ret;
 830                 buf->data += ret;
 831         }
 832
 833         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 834                 kfree(buf);
 835
 836         return ret;
 837 }
 838
 839 /* Assumes epfile->mutex is held. */
 840 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 841                                       void *data, int data_len,
 842                                       struct iov_iter *iter)
 843 {
 844         struct ffs_buffer *buf;
 845
 846         ssize_t ret = copy_to_iter(data, data_len, iter);
 847         if (likely(data_len == ret))
 848                 return ret;
 849
 850         if (unlikely(iov_iter_count(iter)))
 851                 return -EFAULT;
 852
 853         /* See ffs_copy_to_iter for more context. */
 854         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 855                 data_len, ret);
 856
 857         data_len -= ret;
 858         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 859         if (!buf)
 860                 return -ENOMEM;
 861         buf->length = data_len;
 862         buf->data = buf->storage;
 863         memcpy(buf->storage, data + ret, data_len);
 864
 865         /*
 866          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 867          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 868          * in struct ffs_epfile for full read_buffer pointer synchronisation
 869          * story.
 870          */
 871         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 872                 kfree(buf);
 873
 874         return ret;
 875 }
 876
 877 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 878 {
 879         struct ffs_epfile *epfile = file->private_data;
 880         struct usb_request *req;
 881         struct ffs_ep *ep;
 882         char *data = NULL;
 883         ssize_t ret, data_len = -EINVAL;
 884         int halt;
 885
 886         /* Are we still active? */
 887         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 888                 return -ENODEV;
 889
 890         /* Wait for endpoint to be enabled */
 891         ep = epfile->ep;
 892         if (!ep) {
 893                 if (file->f_flags & O_NONBLOCK)
 894                         return -EAGAIN;
 895
 896                 ret = wait_event_interruptible(
 897                                 epfile->ffs->wait, (ep = epfile->ep));
 898                 if (ret)
 899                         return -EINTR;
 900         }
 901
 902         /* Do we halt? */
 903         halt = (!io_data->read == !epfile->in);
 904         if (halt && epfile->isoc)
 905                 return -EINVAL;
 906
 907         /* We will be using request and read_buffer */
 908         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 909         if (unlikely(ret))
 910                 goto error;
 911
 912         /* Allocate & copy */
 913         if (!halt) {
 914                 struct usb_gadget *gadget;
 915
 916                 /*
 917                  * Do we have buffered data from previous partial read?  Check
 918                  * that for synchronous case only because we do not have
 919                  * facility to ‘wake up’ a pending asynchronous read and push
 920                  * buffered data to it which we would need to make things behave
 921                  * consistently.
 922                  */
 923                 if (!io_data->aio && io_data->read) {
 924                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 925                         if (ret)
 926                                 goto error_mutex;
 927                 }
 928
 929                 /*
 930                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 931                  * before the waiting completes, so do not assign to 'gadget'
 932                  * earlier
 933                  */
 934                 gadget = epfile->ffs->gadget;
 935
 936                 spin_lock_irq(&epfile->ffs->eps_lock);
 937                 /* In the meantime, endpoint got disabled or changed. */
 938                 if (epfile->ep != ep) {
 939                         ret = -ESHUTDOWN;
 940                         goto error_lock;
 941                 }
 942                 data_len = iov_iter_count(&io_data->data);
 943                 /*
 944                  * Controller may require buffer size to be aligned to
 945                  * maxpacketsize of an out endpoint.
 946                  */
 947                 if (io_data->read)
 948                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
 949                 spin_unlock_irq(&epfile->ffs->eps_lock);
 950
 951                 data = kmalloc(data_len, GFP_KERNEL);
 952                 if (unlikely(!data)) {
 953                         ret = -ENOMEM;
 954                         goto error_mutex;
 955                 }
 956                 if (!io_data->read &&
 957                     !copy_from_iter_full(data, data_len, &io_data->data)) {
 958                         ret = -EFAULT;
 959                         goto error_mutex;
 960                 }
 961         }
 962
 963         spin_lock_irq(&epfile->ffs->eps_lock);
 964
 965         if (epfile->ep != ep) {
 966                 /* In the meantime, endpoint got disabled or changed. */
 967                 ret = -ESHUTDOWN;
 968         } else if (halt) {
 969                 ret = usb_ep_set_halt(ep->ep);
 970                 if (!ret)
 971                         ret = -EBADMSG;
 972         } else if (unlikely(data_len == -EINVAL)) {
 973                 /*
 974                  * Sanity Check: even though data_len can't be used
 975                  * uninitialized at the time I write this comment, some
 976                  * compilers complain about this situation.
 977                  * In order to keep the code clean from warnings, data_len is
 978                  * being initialized to -EINVAL during its declaration, which
 979                  * means we can't rely on compiler anymore to warn no future
 980                  * changes won't result in data_len being used uninitialized.
 981                  * For such reason, we're adding this redundant sanity check
 982                  * here.
 983                  */
 984                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
 985                 ret = -EINVAL;
 986         } else if (!io_data->aio) {
 987                 DECLARE_COMPLETION_ONSTACK(done);
 988                 bool interrupted = false;
 989
 990                 req = ep->req;
 991                 req->buf      = data;
 992                 req->length   = data_len;
 993
 994                 req->context  = &done;
 995                 req->complete = ffs_epfile_io_complete;
 996
 997                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 998                 if (unlikely(ret < 0))
 999                         goto error_lock;
1000
1001                 spin_unlock_irq(&epfile->ffs->eps_lock);
1002
1003                 if (unlikely(wait_for_completion_interruptible(&done))) {
1004                         /*
1005                          * To avoid race condition with ffs_epfile_io_complete,
1006                          * dequeue the request first then check
1007                          * status. usb_ep_dequeue API should guarantee no race
1008                          * condition with req->complete callback.
1009                          */
1010                         usb_ep_dequeue(ep->ep, req);
1011                         wait_for_completion(&done);
1012                         interrupted = ep->status < 0;
1013                 }
1014
1015                 if (interrupted)
1016                         ret = -EINTR;
1017                 else if (io_data->read && ep->status > 0)
1018                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1019                                                      &io_data->data);
1020                 else
1021                         ret = ep->status;
1022                 goto error_mutex;
1023         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1024                 ret = -ENOMEM;
1025         } else {
1026                 req->buf      = data;
1027                 req->length   = data_len;
1028
1029                 io_data->buf = data;
1030                 io_data->ep = ep->ep;
1031                 io_data->req = req;
1032                 io_data->ffs = epfile->ffs;
1033
1034                 req->context  = io_data;
1035                 req->complete = ffs_epfile_async_io_complete;
1036
1037                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1038                 if (unlikely(ret)) {
1039                         io_data->req = NULL;
1040                         usb_ep_free_request(ep->ep, req);
1041                         goto error_lock;
1042                 }
1043
1044                 ret = -EIOCBQUEUED;
1045                 /*
1046                  * Do not kfree the buffer in this function.  It will be freed
1047                  * by ffs_user_copy_worker.
1048                  */
1049                 data = NULL;
1050         }
1051
1052 error_lock:
1053         spin_unlock_irq(&epfile->ffs->eps_lock);
1054 error_mutex:
1055         mutex_unlock(&epfile->mutex);
1056 error:
1057         kfree(data);
1058         return ret;
1059 }
1060
1061 static int
1062 ffs_epfile_open(struct inode *inode, struct file *file)
1063 {
1064         struct ffs_epfile *epfile = inode->i_private;
1065
1066         ENTER();
1067
1068         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1069                 return -ENODEV;
1070
1071         file->private_data = epfile;
1072         ffs_data_opened(epfile->ffs);
1073
1074         return stream_open(inode, file);
1075 }
1076
1077 static int ffs_aio_cancel(struct kiocb *kiocb)
1078 {
1079         struct ffs_io_data *io_data = kiocb->private;
1080         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1081         unsigned long flags;
1082         int value;
1083
1084         ENTER();
1085
1086         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1087
1088         if (likely(io_data && io_data->ep && io_data->req))
1089                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1090         else
1091                 value = -EINVAL;
1092
1093         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1094
1095         return value;
1096 }
1097
1098 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1099 {
1100         struct ffs_io_data io_data, *p = &io_data;
1101         ssize_t res;
1102
1103         ENTER();
1104
1105         if (!is_sync_kiocb(kiocb)) {
1106                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1107                 if (unlikely(!p))
1108                         return -ENOMEM;
1109                 p->aio = true;
1110         } else {
1111                 memset(p, 0, sizeof(*p));
1112                 p->aio = false;
1113         }
1114
1115         p->read = false;
1116         p->kiocb = kiocb;
1117         p->data = *from;
1118         p->mm = current->mm;
1119
1120         kiocb->private = p;
1121
1122         if (p->aio)
1123                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1124
1125         res = ffs_epfile_io(kiocb->ki_filp, p);
1126         if (res == -EIOCBQUEUED)
1127                 return res;
1128         if (p->aio)
1129                 kfree(p);
1130         else
1131                 *from = p->data;
1132         return res;
1133 }
1134
1135 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1136 {
1137         struct ffs_io_data io_data, *p = &io_data;
1138         ssize_t res;
1139
1140         ENTER();
1141
1142         if (!is_sync_kiocb(kiocb)) {
1143                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1144                 if (unlikely(!p))
1145                         return -ENOMEM;
1146                 p->aio = true;
1147         } else {
1148                 memset(p, 0, sizeof(*p));
1149                 p->aio = false;
1150         }
1151
1152         p->read = true;
1153         p->kiocb = kiocb;
1154         if (p->aio) {
1155                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1156                 if (!p->to_free) {
1157                         kfree(p);
1158                         return -ENOMEM;
1159                 }
1160         } else {
1161                 p->data = *to;
1162                 p->to_free = NULL;
1163         }
1164         p->mm = current->mm;
1165
1166         kiocb->private = p;
1167
1168         if (p->aio)
1169                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1170
1171         res = ffs_epfile_io(kiocb->ki_filp, p);
1172         if (res == -EIOCBQUEUED)
1173                 return res;
1174
1175         if (p->aio) {
1176                 kfree(p->to_free);
1177                 kfree(p);
1178         } else {
1179                 *to = p->data;
1180         }
1181         return res;
1182 }
1183
1184 static int
1185 ffs_epfile_release(struct inode *inode, struct file *file)
1186 {
1187         struct ffs_epfile *epfile = inode->i_private;
1188
1189         ENTER();
1190
1191         __ffs_epfile_read_buffer_free(epfile);
1192         ffs_data_closed(epfile->ffs);
1193
1194         return 0;
1195 }
1196
1197 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1198                              unsigned long value)
1199 {
1200         struct ffs_epfile *epfile = file->private_data;
1201         struct ffs_ep *ep;
1202         int ret;
1203
1204         ENTER();
1205
1206         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1207                 return -ENODEV;
1208
1209         /* Wait for endpoint to be enabled */
1210         ep = epfile->ep;
1211         if (!ep) {
1212                 if (file->f_flags & O_NONBLOCK)
1213                         return -EAGAIN;
1214
1215                 ret = wait_event_interruptible(
1216                                 epfile->ffs->wait, (ep = epfile->ep));
1217                 if (ret)
1218                         return -EINTR;
1219         }
1220
1221         spin_lock_irq(&epfile->ffs->eps_lock);
1222
1223         /* In the meantime, endpoint got disabled or changed. */
1224         if (epfile->ep != ep) {
1225                 spin_unlock_irq(&epfile->ffs->eps_lock);
1226                 return -ESHUTDOWN;
1227         }
1228
1229         switch (code) {
1230         case FUNCTIONFS_FIFO_STATUS:
1231                 ret = usb_ep_fifo_status(epfile->ep->ep);
1232                 break;
1233         case FUNCTIONFS_FIFO_FLUSH:
1234                 usb_ep_fifo_flush(epfile->ep->ep);
1235                 ret = 0;
1236                 break;
1237         case FUNCTIONFS_CLEAR_HALT:
1238                 ret = usb_ep_clear_halt(epfile->ep->ep);
1239                 break;
1240         case FUNCTIONFS_ENDPOINT_REVMAP:
1241                 ret = epfile->ep->num;
1242                 break;
1243         case FUNCTIONFS_ENDPOINT_DESC:
1244         {
1245                 int desc_idx;
1246                 struct usb_endpoint_descriptor desc1, *desc;
1247
1248                 switch (epfile->ffs->gadget->speed) {
1249                 case USB_SPEED_SUPER:
1250                 case USB_SPEED_SUPER_PLUS:
1251                         desc_idx = 2;
1252                         break;
1253                 case USB_SPEED_HIGH:
1254                         desc_idx = 1;
1255                         break;
1256                 default:
1257                         desc_idx = 0;
1258                 }
1259
1260                 desc = epfile->ep->descs[desc_idx];
1261                 memcpy(&desc1, desc, desc->bLength);
1262
1263                 spin_unlock_irq(&epfile->ffs->eps_lock);
1264                 ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
1265                 if (ret)
1266                         ret = -EFAULT;
1267                 return ret;
1268         }
1269         default:
1270                 ret = -ENOTTY;
1271         }
1272         spin_unlock_irq(&epfile->ffs->eps_lock);
1273
1274         return ret;
1275 }
1276
1277 #ifdef CONFIG_COMPAT
1278 static long ffs_epfile_compat_ioctl(struct file *file, unsigned code,
1279                 unsigned long value)
1280 {
1281         return ffs_epfile_ioctl(file, code, value);
1282 }
1283 #endif
1284
1285 static const struct file_operations ffs_epfile_operations = {
1286         .llseek =       no_llseek,
1287
1288         .open =         ffs_epfile_open,
1289         .write_iter =   ffs_epfile_write_iter,
1290         .read_iter =    ffs_epfile_read_iter,
1291         .release =      ffs_epfile_release,
1292         .unlocked_ioctl =       ffs_epfile_ioctl,
1293 #ifdef CONFIG_COMPAT
1294         .compat_ioctl = ffs_epfile_compat_ioctl,
1295 #endif
1296 };
1297
1298
1299 /* File system and super block operations ***********************************/
1300
1301 /*
1302  * Mounting the file system creates a controller file, used first for
1303  * function configuration then later for event monitoring.
1304  */
1305
1306 static struct inode *__must_check
1307 ffs_sb_make_inode(struct super_block *sb, void *data,
1308                   const struct file_operations *fops,
1309                   const struct inode_operations *iops,
1310                   struct ffs_file_perms *perms)
1311 {
1312         struct inode *inode;
1313
1314         ENTER();
1315
1316         inode = new_inode(sb);
1317
1318         if (likely(inode)) {
1319                 struct timespec64 ts = current_time(inode);
1320
1321                 inode->i_ino     = get_next_ino();
1322                 inode->i_mode    = perms->mode;
1323                 inode->i_uid     = perms->uid;
1324                 inode->i_gid     = perms->gid;
1325                 inode->i_atime   = ts;
1326                 inode->i_mtime   = ts;
1327                 inode->i_ctime   = ts;
1328                 inode->i_private = data;
1329                 if (fops)
1330                         inode->i_fop = fops;
1331                 if (iops)
1332                         inode->i_op  = iops;
1333         }
1334
1335         return inode;
1336 }
1337
1338 /* Create "regular" file */
1339 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1340                                         const char *name, void *data,
1341                                         const struct file_operations *fops)
1342 {
1343         struct ffs_data *ffs = sb->s_fs_info;
1344         struct dentry   *dentry;
1345         struct inode    *inode;
1346
1347         ENTER();
1348
1349         dentry = d_alloc_name(sb->s_root, name);
1350         if (unlikely(!dentry))
1351                 return NULL;
1352
1353         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1354         if (unlikely(!inode)) {
1355                 dput(dentry);
1356                 return NULL;
1357         }
1358
1359         d_add(dentry, inode);
1360         return dentry;
1361 }
1362
1363 /* Super block */
1364 static const struct super_operations ffs_sb_operations = {
1365         .statfs =       simple_statfs,
1366         .drop_inode =   generic_delete_inode,
1367 };
1368
1369 struct ffs_sb_fill_data {
1370         struct ffs_file_perms perms;
1371         umode_t root_mode;
1372         const char *dev_name;
1373         bool no_disconnect;
1374         struct ffs_data *ffs_data;
1375 };
1376
1377 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1378 {
1379         struct ffs_sb_fill_data *data = _data;
1380         struct inode    *inode;
1381         struct ffs_data *ffs = data->ffs_data;
1382
1383         ENTER();
1384
1385         ffs->sb              = sb;
1386         data->ffs_data       = NULL;
1387         sb->s_fs_info        = ffs;
1388         sb->s_blocksize      = PAGE_SIZE;
1389         sb->s_blocksize_bits = PAGE_SHIFT;
1390         sb->s_magic          = FUNCTIONFS_MAGIC;
1391         sb->s_op             = &ffs_sb_operations;
1392         sb->s_time_gran      = 1;
1393
1394         /* Root inode */
1395         data->perms.mode = data->root_mode;
1396         inode = ffs_sb_make_inode(sb, NULL,
1397                                   &simple_dir_operations,
1398                                   &simple_dir_inode_operations,
1399                                   &data->perms);
1400         sb->s_root = d_make_root(inode);
1401         if (unlikely(!sb->s_root))
1402                 return -ENOMEM;
1403
1404         /* EP0 file */
1405         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1406                                          &ffs_ep0_operations)))
1407                 return -ENOMEM;
1408
1409         return 0;
1410 }
1411
1412 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1413 {
1414         ENTER();
1415
1416         if (!opts || !*opts)
1417                 return 0;
1418
1419         for (;;) {
1420                 unsigned long value;
1421                 char *eq, *comma;
1422
1423                 /* Option limit */
1424                 comma = strchr(opts, ',');
1425                 if (comma)
1426                         *comma = 0;
1427
1428                 /* Value limit */
1429                 eq = strchr(opts, '=');
1430                 if (unlikely(!eq)) {
1431                         pr_err("'=' missing in %s\n", opts);
1432                         return -EINVAL;
1433                 }
1434                 *eq = 0;
1435
1436                 /* Parse value */
1437                 if (kstrtoul(eq + 1, 0, &value)) {
1438                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1439                         return -EINVAL;
1440                 }
1441
1442                 /* Interpret option */
1443                 switch (eq - opts) {
1444                 case 13:
1445                         if (!memcmp(opts, "no_disconnect", 13))
1446                                 data->no_disconnect = !!value;
1447                         else
1448                                 goto invalid;
1449                         break;
1450                 case 5:
1451                         if (!memcmp(opts, "rmode", 5))
1452                                 data->root_mode  = (value & 0555) | S_IFDIR;
1453                         else if (!memcmp(opts, "fmode", 5))
1454                                 data->perms.mode = (value & 0666) | S_IFREG;
1455                         else
1456                                 goto invalid;
1457                         break;
1458
1459                 case 4:
1460                         if (!memcmp(opts, "mode", 4)) {
1461                                 data->root_mode  = (value & 0555) | S_IFDIR;
1462                                 data->perms.mode = (value & 0666) | S_IFREG;
1463                         } else {
1464                                 goto invalid;
1465                         }
1466                         break;
1467
1468                 case 3:
1469                         if (!memcmp(opts, "uid", 3)) {
1470                                 data->perms.uid = make_kuid(current_user_ns(), value);
1471                                 if (!uid_valid(data->perms.uid)) {
1472                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1473                                         return -EINVAL;
1474                                 }
1475                         } else if (!memcmp(opts, "gid", 3)) {
1476                                 data->perms.gid = make_kgid(current_user_ns(), value);
1477                                 if (!gid_valid(data->perms.gid)) {
1478                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1479                                         return -EINVAL;
1480                                 }
1481                         } else {
1482                                 goto invalid;
1483                         }
1484                         break;
1485
1486                 default:
1487 invalid:
1488                         pr_err("%s: invalid option\n", opts);
1489                         return -EINVAL;
1490                 }
1491
1492                 /* Next iteration */
1493                 if (!comma)
1494                         break;
1495                 opts = comma + 1;
1496         }
1497
1498         return 0;
1499 }
1500
1501 /* "mount -t functionfs dev_name /dev/function" ends up here */
1502
1503 static struct dentry *
1504 ffs_fs_mount(struct file_system_type *t, int flags,
1505               const char *dev_name, void *opts)
1506 {
1507         struct ffs_sb_fill_data data = {
1508                 .perms = {
1509                         .mode = S_IFREG | 0600,
1510                         .uid = GLOBAL_ROOT_UID,
1511                         .gid = GLOBAL_ROOT_GID,
1512                 },
1513                 .root_mode = S_IFDIR | 0500,
1514                 .no_disconnect = false,
1515         };
1516         struct dentry *rv;
1517         int ret;
1518         struct ffs_data *ffs;
1519
1520         ENTER();
1521
1522         ret = ffs_fs_parse_opts(&data, opts);
1523         if (unlikely(ret < 0))
1524                 return ERR_PTR(ret);
1525
1526         ffs = ffs_data_new(dev_name);
1527         if (unlikely(!ffs))
1528                 return ERR_PTR(-ENOMEM);
1529         ffs->file_perms = data.perms;
1530         ffs->no_disconnect = data.no_disconnect;
1531
1532         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1533         if (unlikely(!ffs->dev_name)) {
1534                 ffs_data_put(ffs);
1535                 return ERR_PTR(-ENOMEM);
1536         }
1537
1538         ret = ffs_acquire_dev(dev_name, ffs);
1539         if (ret) {
1540                 ffs_data_put(ffs);
1541                 return ERR_PTR(ret);
1542         }
1543         data.ffs_data = ffs;
1544
1545         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1546         if (IS_ERR(rv) && data.ffs_data)
1547                 ffs_data_put(data.ffs_data);
1548         return rv;
1549 }
1550
1551 static void
1552 ffs_fs_kill_sb(struct super_block *sb)
1553 {
1554         ENTER();
1555
1556         kill_litter_super(sb);
1557         if (sb->s_fs_info)
1558                 ffs_data_closed(sb->s_fs_info);
1559 }
1560
1561 static struct file_system_type ffs_fs_type = {
1562         .owner          = THIS_MODULE,
1563         .name           = "functionfs",
1564         .mount          = ffs_fs_mount,
1565         .kill_sb        = ffs_fs_kill_sb,
1566 };
1567 MODULE_ALIAS_FS("functionfs");
1568
1569
1570 /* Driver's main init/cleanup functions *************************************/
1571
1572 static int functionfs_init(void)
1573 {
1574         int ret;
1575
1576         ENTER();
1577
1578         ret = register_filesystem(&ffs_fs_type);
1579         if (likely(!ret))
1580                 pr_info("file system registered\n");
1581         else
1582                 pr_err("failed registering file system (%d)\n", ret);
1583
1584         return ret;
1585 }
1586
1587 static void functionfs_cleanup(void)
1588 {
1589         ENTER();
1590
1591         pr_info("unloading\n");
1592         unregister_filesystem(&ffs_fs_type);
1593 }
1594
1595
1596 /* ffs_data and ffs_function construction and destruction code **************/
1597
1598 static void ffs_data_clear(struct ffs_data *ffs);
1599 static void ffs_data_reset(struct ffs_data *ffs);
1600
1601 static void ffs_data_get(struct ffs_data *ffs)
1602 {
1603         ENTER();
1604
1605         refcount_inc(&ffs->ref);
1606 }
1607
1608 static void ffs_data_opened(struct ffs_data *ffs)
1609 {
1610         ENTER();
1611
1612         refcount_inc(&ffs->ref);
1613         if (atomic_add_return(1, &ffs->opened) == 1 &&
1614                         ffs->state == FFS_DEACTIVATED) {
1615                 ffs->state = FFS_CLOSING;
1616                 ffs_data_reset(ffs);
1617         }
1618 }
1619
1620 static void ffs_data_put(struct ffs_data *ffs)
1621 {
1622         ENTER();
1623
1624         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1625                 pr_info("%s(): freeing\n", __func__);
1626                 ffs_data_clear(ffs);
1627                 ffs_release_dev(ffs->private_data);
1628                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1629                        waitqueue_active(&ffs->ep0req_completion.wait) ||
1630                        waitqueue_active(&ffs->wait));
1631                 destroy_workqueue(ffs->io_completion_wq);
1632                 kfree(ffs->dev_name);
1633                 kfree(ffs);
1634         }
1635 }
1636
1637 static void ffs_data_closed(struct ffs_data *ffs)
1638 {
1639         struct ffs_epfile *epfiles;
1640         unsigned long flags;
1641
1642         ENTER();
1643
1644         if (atomic_dec_and_test(&ffs->opened)) {
1645                 if (ffs->no_disconnect) {
1646                         ffs->state = FFS_DEACTIVATED;
1647                         spin_lock_irqsave(&ffs->eps_lock, flags);
1648                         epfiles = ffs->epfiles;
1649                         ffs->epfiles = NULL;
1650                         spin_unlock_irqrestore(&ffs->eps_lock,
1651                                                         flags);
1652
1653                         if (epfiles)
1654                                 ffs_epfiles_destroy(epfiles,
1655                                                  ffs->eps_count);
1656
1657                         if (ffs->setup_state == FFS_SETUP_PENDING)
1658                                 __ffs_ep0_stall(ffs);
1659                 } else {
1660                         ffs->state = FFS_CLOSING;
1661                         ffs_data_reset(ffs);
1662                 }
1663         }
1664         if (atomic_read(&ffs->opened) < 0) {
1665                 ffs->state = FFS_CLOSING;
1666                 ffs_data_reset(ffs);
1667         }
1668
1669         ffs_data_put(ffs);
1670 }
1671
1672 static struct ffs_data *ffs_data_new(const char *dev_name)
1673 {
1674         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1675         if (unlikely(!ffs))
1676                 return NULL;
1677
1678         ENTER();
1679
1680         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1681         if (!ffs->io_completion_wq) {
1682                 kfree(ffs);
1683                 return NULL;
1684         }
1685
1686         refcount_set(&ffs->ref, 1);
1687         atomic_set(&ffs->opened, 0);
1688         ffs->state = FFS_READ_DESCRIPTORS;
1689         mutex_init(&ffs->mutex);
1690         spin_lock_init(&ffs->eps_lock);
1691         init_waitqueue_head(&ffs->ev.waitq);
1692         init_waitqueue_head(&ffs->wait);
1693         init_completion(&ffs->ep0req_completion);
1694
1695         /* XXX REVISIT need to update it in some places, or do we? */
1696         ffs->ev.can_stall = 1;
1697
1698         return ffs;
1699 }
1700
1701 static void ffs_data_clear(struct ffs_data *ffs)
1702 {
1703         struct ffs_epfile *epfiles;
1704         unsigned long flags;
1705
1706         ENTER();
1707
1708         ffs_closed(ffs);
1709
1710         BUG_ON(ffs->gadget);
1711
1712         spin_lock_irqsave(&ffs->eps_lock, flags);
1713         epfiles = ffs->epfiles;
1714         ffs->epfiles = NULL;
1715         spin_unlock_irqrestore(&ffs->eps_lock, flags);
1716
1717         /*
1718          * potential race possible between ffs_func_eps_disable
1719          * & ffs_epfile_release therefore maintaining a local
1720          * copy of epfile will save us from use-after-free.
1721          */
1722         if (epfiles) {
1723                 ffs_epfiles_destroy(epfiles, ffs->eps_count);
1724                 ffs->epfiles = NULL;
1725         }
1726
1727         if (ffs->ffs_eventfd) {
1728                 eventfd_ctx_put(ffs->ffs_eventfd);
1729                 ffs->ffs_eventfd = NULL;
1730         }
1731
1732         kfree(ffs->raw_descs_data);
1733         kfree(ffs->raw_strings);
1734         kfree(ffs->stringtabs);
1735 }
1736
1737 static void ffs_data_reset(struct ffs_data *ffs)
1738 {
1739         ENTER();
1740
1741         ffs_data_clear(ffs);
1742
1743         ffs->raw_descs_data = NULL;
1744         ffs->raw_descs = NULL;
1745         ffs->raw_strings = NULL;
1746         ffs->stringtabs = NULL;
1747
1748         ffs->raw_descs_length = 0;
1749         ffs->fs_descs_count = 0;
1750         ffs->hs_descs_count = 0;
1751         ffs->ss_descs_count = 0;
1752
1753         ffs->strings_count = 0;
1754         ffs->interfaces_count = 0;
1755         ffs->eps_count = 0;
1756
1757         ffs->ev.count = 0;
1758
1759         ffs->state = FFS_READ_DESCRIPTORS;
1760         ffs->setup_state = FFS_NO_SETUP;
1761         ffs->flags = 0;
1762
1763         ffs->ms_os_descs_ext_prop_count = 0;
1764         ffs->ms_os_descs_ext_prop_name_len = 0;
1765         ffs->ms_os_descs_ext_prop_data_len = 0;
1766 }
1767
1768
1769 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1770 {
1771         struct usb_gadget_strings **lang;
1772         int first_id;
1773
1774         ENTER();
1775
1776         if (WARN_ON(ffs->state != FFS_ACTIVE
1777                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1778                 return -EBADFD;
1779
1780         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1781         if (unlikely(first_id < 0))
1782                 return first_id;
1783
1784         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1785         if (unlikely(!ffs->ep0req))
1786                 return -ENOMEM;
1787         ffs->ep0req->complete = ffs_ep0_complete;
1788         ffs->ep0req->context = ffs;
1789
1790         lang = ffs->stringtabs;
1791         if (lang) {
1792                 for (; *lang; ++lang) {
1793                         struct usb_string *str = (*lang)->strings;
1794                         int id = first_id;
1795                         for (; str->s; ++id, ++str)
1796                                 str->id = id;
1797                 }
1798         }
1799
1800         ffs->gadget = cdev->gadget;
1801         ffs_data_get(ffs);
1802         return 0;
1803 }
1804
1805 static void functionfs_unbind(struct ffs_data *ffs)
1806 {
1807         ENTER();
1808
1809         if (!WARN_ON(!ffs->gadget)) {
1810                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1811                 ffs->ep0req = NULL;
1812                 ffs->gadget = NULL;
1813                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1814                 ffs_data_put(ffs);
1815         }
1816 }
1817
1818 static int ffs_epfiles_create(struct ffs_data *ffs)
1819 {
1820         struct ffs_epfile *epfile, *epfiles;
1821         unsigned i, count;
1822
1823         ENTER();
1824
1825         count = ffs->eps_count;
1826         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1827         if (!epfiles)
1828                 return -ENOMEM;
1829
1830         epfile = epfiles;
1831         for (i = 1; i <= count; ++i, ++epfile) {
1832                 epfile->ffs = ffs;
1833                 mutex_init(&epfile->mutex);
1834                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1835                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1836                 else
1837                         sprintf(epfile->name, "ep%u", i);
1838                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1839                                                  epfile,
1840                                                  &ffs_epfile_operations);
1841                 if (unlikely(!epfile->dentry)) {
1842                         ffs_epfiles_destroy(epfiles, i - 1);
1843                         return -ENOMEM;
1844                 }
1845         }
1846
1847         ffs->epfiles = epfiles;
1848         return 0;
1849 }
1850
1851 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1852 {
1853         struct ffs_epfile *epfile = epfiles;
1854
1855         ENTER();
1856
1857         for (; count; --count, ++epfile) {
1858                 BUG_ON(mutex_is_locked(&epfile->mutex));
1859                 if (epfile->dentry) {
1860                         d_delete(epfile->dentry);
1861                         dput(epfile->dentry);
1862                         epfile->dentry = NULL;
1863                 }
1864         }
1865
1866         kfree(epfiles);
1867 }
1868
1869 static void ffs_func_eps_disable(struct ffs_function *func)
1870 {
1871         struct ffs_ep *ep;
1872         struct ffs_epfile *epfile;
1873         unsigned short count;
1874         unsigned long flags;
1875
1876         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1877         count = func->ffs->eps_count;
1878         epfile = func->ffs->epfiles;
1879         ep = func->eps;
1880         while (count--) {
1881                 /* pending requests get nuked */
1882                 if (likely(ep->ep))
1883                         usb_ep_disable(ep->ep);
1884                 ++ep;
1885
1886                 if (epfile) {
1887                         epfile->ep = NULL;
1888                         __ffs_epfile_read_buffer_free(epfile);
1889                         ++epfile;
1890                 }
1891         }
1892         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1893 }
1894
1895 static int ffs_func_eps_enable(struct ffs_function *func)
1896 {
1897         struct ffs_data *ffs;
1898         struct ffs_ep *ep;
1899         struct ffs_epfile *epfile;
1900         unsigned short count;
1901         unsigned long flags;
1902         int ret = 0;
1903
1904         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1905         ffs = func->ffs;
1906         ep = func->eps;
1907         epfile = ffs->epfiles;
1908         count = ffs->eps_count;
1909         while(count--) {
1910                 ep->ep->driver_data = ep;
1911
1912                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1913                 if (ret) {
1914                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1915                                         __func__, ep->ep->name, ret);
1916                         break;
1917                 }
1918
1919                 ret = usb_ep_enable(ep->ep);
1920                 if (likely(!ret)) {
1921                         epfile->ep = ep;
1922                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1923                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1924                 } else {
1925                         break;
1926                 }
1927
1928                 ++ep;
1929                 ++epfile;
1930         }
1931
1932         wake_up_interruptible(&ffs->wait);
1933         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1934
1935         return ret;
1936 }
1937
1938
1939 /* Parsing and building descriptors and strings *****************************/
1940
1941 /*
1942  * This validates if data pointed by data is a valid USB descriptor as
1943  * well as record how many interfaces, endpoints and strings are
1944  * required by given configuration.  Returns address after the
1945  * descriptor or NULL if data is invalid.
1946  */
1947
1948 enum ffs_entity_type {
1949         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1950 };
1951
1952 enum ffs_os_desc_type {
1953         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1954 };
1955
1956 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1957                                    u8 *valuep,
1958                                    struct usb_descriptor_header *desc,
1959                                    void *priv);
1960
1961 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1962                                     struct usb_os_desc_header *h, void *data,
1963                                     unsigned len, void *priv);
1964
1965 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1966                                            ffs_entity_callback entity,
1967                                            void *priv)
1968 {
1969         struct usb_descriptor_header *_ds = (void *)data;
1970         u8 length;
1971         int ret;
1972
1973         ENTER();
1974
1975         /* At least two bytes are required: length and type */
1976         if (len < 2) {
1977                 pr_vdebug("descriptor too short\n");
1978                 return -EINVAL;
1979         }
1980
1981         /* If we have at least as many bytes as the descriptor takes? */
1982         length = _ds->bLength;
1983         if (len < length) {
1984                 pr_vdebug("descriptor longer then available data\n");
1985                 return -EINVAL;
1986         }
1987
1988 #define __entity_check_INTERFACE(val)  1
1989 #define __entity_check_STRING(val)     (val)
1990 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1991 #define __entity(type, val) do {                                        \
1992                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1993                 if (unlikely(!__entity_check_ ##type(val))) {           \
1994                         pr_vdebug("invalid entity's value\n");          \
1995                         return -EINVAL;                                 \
1996                 }                                                       \
1997                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1998                 if (unlikely(ret < 0)) {                                \
1999                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2000                                  (val), ret);                           \
2001                         return ret;                                     \
2002                 }                                                       \
2003         } while (0)
2004
2005         /* Parse descriptor depending on type. */
2006         switch (_ds->bDescriptorType) {
2007         case USB_DT_DEVICE:
2008         case USB_DT_CONFIG:
2009         case USB_DT_STRING:
2010         case USB_DT_DEVICE_QUALIFIER:
2011                 /* function can't have any of those */
2012                 pr_vdebug("descriptor reserved for gadget: %d\n",
2013                       _ds->bDescriptorType);
2014                 return -EINVAL;
2015
2016         case USB_DT_INTERFACE: {
2017                 struct usb_interface_descriptor *ds = (void *)_ds;
2018                 pr_vdebug("interface descriptor\n");
2019                 if (length != sizeof *ds)
2020                         goto inv_length;
2021
2022                 __entity(INTERFACE, ds->bInterfaceNumber);
2023                 if (ds->iInterface)
2024                         __entity(STRING, ds->iInterface);
2025         }
2026                 break;
2027
2028         case USB_DT_ENDPOINT: {
2029                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2030                 pr_vdebug("endpoint descriptor\n");
2031                 if (length != USB_DT_ENDPOINT_SIZE &&
2032                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2033                         goto inv_length;
2034                 __entity(ENDPOINT, ds->bEndpointAddress);
2035         }
2036                 break;
2037
2038         case HID_DT_HID:
2039                 pr_vdebug("hid descriptor\n");
2040                 if (length != sizeof(struct hid_descriptor))
2041                         goto inv_length;
2042                 break;
2043
2044         case USB_DT_OTG:
2045                 if (length != sizeof(struct usb_otg_descriptor))
2046                         goto inv_length;
2047                 break;
2048
2049         case USB_DT_INTERFACE_ASSOCIATION: {
2050                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2051                 pr_vdebug("interface association descriptor\n");
2052                 if (length != sizeof *ds)
2053                         goto inv_length;
2054                 if (ds->iFunction)
2055                         __entity(STRING, ds->iFunction);
2056         }
2057                 break;
2058
2059         case USB_DT_SS_ENDPOINT_COMP:
2060                 pr_vdebug("EP SS companion descriptor\n");
2061                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2062                         goto inv_length;
2063                 break;
2064
2065         case USB_DT_OTHER_SPEED_CONFIG:
2066         case USB_DT_INTERFACE_POWER:
2067         case USB_DT_DEBUG:
2068         case USB_DT_SECURITY:
2069         case USB_DT_CS_RADIO_CONTROL:
2070                 /* TODO */
2071                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2072                 return -EINVAL;
2073
2074         default:
2075                 /* We should never be here */
2076                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2077                 return -EINVAL;
2078
2079 inv_length:
2080                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2081                           _ds->bLength, _ds->bDescriptorType);
2082                 return -EINVAL;
2083         }
2084
2085 #undef __entity
2086 #undef __entity_check_DESCRIPTOR
2087 #undef __entity_check_INTERFACE
2088 #undef __entity_check_STRING
2089 #undef __entity_check_ENDPOINT
2090
2091         return length;
2092 }
2093
2094 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2095                                      ffs_entity_callback entity, void *priv)
2096 {
2097         const unsigned _len = len;
2098         unsigned long num = 0;
2099
2100         ENTER();
2101
2102         for (;;) {
2103                 int ret;
2104
2105                 if (num == count)
2106                         data = NULL;
2107
2108                 /* Record "descriptor" entity */
2109                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2110                 if (unlikely(ret < 0)) {
2111                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2112                                  num, ret);
2113                         return ret;
2114                 }
2115
2116                 if (!data)
2117                         return _len - len;
2118
2119                 ret = ffs_do_single_desc(data, len, entity, priv);
2120                 if (unlikely(ret < 0)) {
2121                         pr_debug("%s returns %d\n", __func__, ret);
2122                         return ret;
2123                 }
2124
2125                 len -= ret;
2126                 data += ret;
2127                 ++num;
2128         }
2129 }
2130
2131 static int __ffs_data_do_entity(enum ffs_entity_type type,
2132                                 u8 *valuep, struct usb_descriptor_header *desc,
2133                                 void *priv)
2134 {
2135         struct ffs_desc_helper *helper = priv;
2136         struct usb_endpoint_descriptor *d;
2137
2138         ENTER();
2139
2140         switch (type) {
2141         case FFS_DESCRIPTOR:
2142                 break;
2143
2144         case FFS_INTERFACE:
2145                 /*
2146                  * Interfaces are indexed from zero so if we
2147                  * encountered interface "n" then there are at least
2148                  * "n+1" interfaces.
2149                  */
2150                 if (*valuep >= helper->interfaces_count)
2151                         helper->interfaces_count = *valuep + 1;
2152                 break;
2153
2154         case FFS_STRING:
2155                 /*
2156                  * Strings are indexed from 1 (0 is reserved
2157                  * for languages list)
2158                  */
2159                 if (*valuep > helper->ffs->strings_count)
2160                         helper->ffs->strings_count = *valuep;
2161                 break;
2162
2163         case FFS_ENDPOINT:
2164                 d = (void *)desc;
2165                 helper->eps_count++;
2166                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2167                         return -EINVAL;
2168                 /* Check if descriptors for any speed were already parsed */
2169                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2170                         helper->ffs->eps_addrmap[helper->eps_count] =
2171                                 d->bEndpointAddress;
2172                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2173                                 d->bEndpointAddress)
2174                         return -EINVAL;
2175                 break;
2176         }
2177
2178         return 0;
2179 }
2180
2181 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2182                                    struct usb_os_desc_header *desc)
2183 {
2184         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2185         u16 w_index = le16_to_cpu(desc->wIndex);
2186
2187         if (bcd_version != 1) {
2188                 pr_vdebug("unsupported os descriptors version: %d",
2189                           bcd_version);
2190                 return -EINVAL;
2191         }
2192         switch (w_index) {
2193         case 0x4:
2194                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2195                 break;
2196         case 0x5:
2197                 *next_type = FFS_OS_DESC_EXT_PROP;
2198                 break;
2199         default:
2200                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2201                 return -EINVAL;
2202         }
2203
2204         return sizeof(*desc);
2205 }
2206
2207 /*
2208  * Process all extended compatibility/extended property descriptors
2209  * of a feature descriptor
2210  */
2211 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2212                                               enum ffs_os_desc_type type,
2213                                               u16 feature_count,
2214                                               ffs_os_desc_callback entity,
2215                                               void *priv,
2216                                               struct usb_os_desc_header *h)
2217 {
2218         int ret;
2219         const unsigned _len = len;
2220
2221         ENTER();
2222
2223         /* loop over all ext compat/ext prop descriptors */
2224         while (feature_count--) {
2225                 ret = entity(type, h, data, len, priv);
2226                 if (unlikely(ret < 0)) {
2227                         pr_debug("bad OS descriptor, type: %d\n", type);
2228                         return ret;
2229                 }
2230                 data += ret;
2231                 len -= ret;
2232         }
2233         return _len - len;
2234 }
2235
2236 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2237 static int __must_check ffs_do_os_descs(unsigned count,
2238                                         char *data, unsigned len,
2239                                         ffs_os_desc_callback entity, void *priv)
2240 {
2241         const unsigned _len = len;
2242         unsigned long num = 0;
2243
2244         ENTER();
2245
2246         for (num = 0; num < count; ++num) {
2247                 int ret;
2248                 enum ffs_os_desc_type type;
2249                 u16 feature_count;
2250                 struct usb_os_desc_header *desc = (void *)data;
2251
2252                 if (len < sizeof(*desc))
2253                         return -EINVAL;
2254
2255                 /*
2256                  * Record "descriptor" entity.
2257                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2258                  * Move the data pointer to the beginning of extended
2259                  * compatibilities proper or extended properties proper
2260                  * portions of the data
2261                  */
2262                 if (le32_to_cpu(desc->dwLength) > len)
2263                         return -EINVAL;
2264
2265                 ret = __ffs_do_os_desc_header(&type, desc);
2266                 if (unlikely(ret < 0)) {
2267                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2268                                  num, ret);
2269                         return ret;
2270                 }
2271                 /*
2272                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2273                  */
2274                 feature_count = le16_to_cpu(desc->wCount);
2275                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2276                     (feature_count > 255 || desc->Reserved))
2277                                 return -EINVAL;
2278                 len -= ret;
2279                 data += ret;
2280
2281                 /*
2282                  * Process all function/property descriptors
2283                  * of this Feature Descriptor
2284                  */
2285                 ret = ffs_do_single_os_desc(data, len, type,
2286                                             feature_count, entity, priv, desc);
2287                 if (unlikely(ret < 0)) {
2288                         pr_debug("%s returns %d\n", __func__, ret);
2289                         return ret;
2290                 }
2291
2292                 len -= ret;
2293                 data += ret;
2294         }
2295         return _len - len;
2296 }
2297
2298 /**
2299  * Validate contents of the buffer from userspace related to OS descriptors.
2300  */
2301 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2302                                  struct usb_os_desc_header *h, void *data,
2303                                  unsigned len, void *priv)
2304 {
2305         struct ffs_data *ffs = priv;
2306         u8 length;
2307
2308         ENTER();
2309
2310         switch (type) {
2311         case FFS_OS_DESC_EXT_COMPAT: {
2312                 struct usb_ext_compat_desc *d = data;
2313                 int i;
2314
2315                 if (len < sizeof(*d) ||
2316                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2317                         return -EINVAL;
2318                 if (d->Reserved1 != 1) {
2319                         /*
2320                          * According to the spec, Reserved1 must be set to 1
2321                          * but older kernels incorrectly rejected non-zero
2322                          * values.  We fix it here to avoid returning EINVAL
2323                          * in response to values we used to accept.
2324                          */
2325                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2326                         d->Reserved1 = 1;
2327                 }
2328                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2329                         if (d->Reserved2[i])
2330                                 return -EINVAL;
2331
2332                 length = sizeof(struct usb_ext_compat_desc);
2333         }
2334                 break;
2335         case FFS_OS_DESC_EXT_PROP: {
2336                 struct usb_ext_prop_desc *d = data;
2337                 u32 type, pdl;
2338                 u16 pnl;
2339
2340                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2341                         return -EINVAL;
2342                 length = le32_to_cpu(d->dwSize);
2343                 if (len < length)
2344                         return -EINVAL;
2345                 type = le32_to_cpu(d->dwPropertyDataType);
2346                 if (type < USB_EXT_PROP_UNICODE ||
2347                     type > USB_EXT_PROP_UNICODE_MULTI) {
2348                         pr_vdebug("unsupported os descriptor property type: %d",
2349                                   type);
2350                         return -EINVAL;
2351                 }
2352                 pnl = le16_to_cpu(d->wPropertyNameLength);
2353                 if (length < 14 + pnl) {
2354                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2355                                   length, pnl, type);
2356                         return -EINVAL;
2357                 }
2358                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2359                 if (length != 14 + pnl + pdl) {
2360                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2361                                   length, pnl, pdl, type);
2362                         return -EINVAL;
2363                 }
2364                 ++ffs->ms_os_descs_ext_prop_count;
2365                 /* property name reported to the host as "WCHAR"s */
2366                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2367                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2368         }
2369                 break;
2370         default:
2371                 pr_vdebug("unknown descriptor: %d\n", type);
2372                 return -EINVAL;
2373         }
2374         return length;
2375 }
2376
2377 static int __ffs_data_got_descs(struct ffs_data *ffs,
2378                                 char *const _data, size_t len)
2379 {
2380         char *data = _data, *raw_descs;
2381         unsigned os_descs_count = 0, counts[3], flags;
2382         int ret = -EINVAL, i;
2383         struct ffs_desc_helper helper;
2384
2385         ENTER();
2386
2387         if (get_unaligned_le32(data + 4) != len)
2388                 goto error;
2389
2390         switch (get_unaligned_le32(data)) {
2391         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2392                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2393                 data += 8;
2394                 len  -= 8;
2395                 break;
2396         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2397                 flags = get_unaligned_le32(data + 8);
2398                 ffs->user_flags = flags;
2399                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2400                               FUNCTIONFS_HAS_HS_DESC |
2401                               FUNCTIONFS_HAS_SS_DESC |
2402                               FUNCTIONFS_HAS_MS_OS_DESC |
2403                               FUNCTIONFS_VIRTUAL_ADDR |
2404                               FUNCTIONFS_EVENTFD |
2405                               FUNCTIONFS_ALL_CTRL_RECIP |
2406                               FUNCTIONFS_CONFIG0_SETUP)) {
2407                         ret = -ENOSYS;
2408                         goto error;
2409                 }
2410                 data += 12;
2411                 len  -= 12;
2412                 break;
2413         default:
2414                 goto error;
2415         }
2416
2417         if (flags & FUNCTIONFS_EVENTFD) {
2418                 if (len < 4)
2419                         goto error;
2420                 ffs->ffs_eventfd =
2421                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2422                 if (IS_ERR(ffs->ffs_eventfd)) {
2423                         ret = PTR_ERR(ffs->ffs_eventfd);
2424                         ffs->ffs_eventfd = NULL;
2425                         goto error;
2426                 }
2427                 data += 4;
2428                 len  -= 4;
2429         }
2430
2431         /* Read fs_count, hs_count and ss_count (if present) */
2432         for (i = 0; i < 3; ++i) {
2433                 if (!(flags & (1 << i))) {
2434                         counts[i] = 0;
2435                 } else if (len < 4) {
2436                         goto error;
2437                 } else {
2438                         counts[i] = get_unaligned_le32(data);
2439                         data += 4;
2440                         len  -= 4;
2441                 }
2442         }
2443         if (flags & (1 << i)) {
2444                 if (len < 4) {
2445                         goto error;
2446                 }
2447                 os_descs_count = get_unaligned_le32(data);
2448                 data += 4;
2449                 len -= 4;
2450         };
2451
2452         /* Read descriptors */
2453         raw_descs = data;
2454         helper.ffs = ffs;
2455         for (i = 0; i < 3; ++i) {
2456                 if (!counts[i])
2457                         continue;
2458                 helper.interfaces_count = 0;
2459                 helper.eps_count = 0;
2460                 ret = ffs_do_descs(counts[i], data, len,
2461                                    __ffs_data_do_entity, &helper);
2462                 if (ret < 0)
2463                         goto error;
2464                 if (!ffs->eps_count && !ffs->interfaces_count) {
2465                         ffs->eps_count = helper.eps_count;
2466                         ffs->interfaces_count = helper.interfaces_count;
2467                 } else {
2468                         if (ffs->eps_count != helper.eps_count) {
2469                                 ret = -EINVAL;
2470                                 goto error;
2471                         }
2472                         if (ffs->interfaces_count != helper.interfaces_count) {
2473                                 ret = -EINVAL;
2474                                 goto error;
2475                         }
2476                 }
2477                 data += ret;
2478                 len  -= ret;
2479         }
2480         if (os_descs_count) {
2481                 ret = ffs_do_os_descs(os_descs_count, data, len,
2482                                       __ffs_data_do_os_desc, ffs);
2483                 if (ret < 0)
2484                         goto error;
2485                 data += ret;
2486                 len -= ret;
2487         }
2488
2489         if (raw_descs == data || len) {
2490                 ret = -EINVAL;
2491                 goto error;
2492         }
2493
2494         ffs->raw_descs_data     = _data;
2495         ffs->raw_descs          = raw_descs;
2496         ffs->raw_descs_length   = data - raw_descs;
2497         ffs->fs_descs_count     = counts[0];
2498         ffs->hs_descs_count     = counts[1];
2499         ffs->ss_descs_count     = counts[2];
2500         ffs->ms_os_descs_count  = os_descs_count;
2501
2502         return 0;
2503
2504 error:
2505         kfree(_data);
2506         return ret;
2507 }
2508
2509 static int __ffs_data_got_strings(struct ffs_data *ffs,
2510                                   char *const _data, size_t len)
2511 {
2512         u32 str_count, needed_count, lang_count;
2513         struct usb_gadget_strings **stringtabs, *t;
2514         const char *data = _data;
2515         struct usb_string *s;
2516
2517         ENTER();
2518
2519         if (unlikely(len < 16 ||
2520                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2521                      get_unaligned_le32(data + 4) != len))
2522                 goto error;
2523         str_count  = get_unaligned_le32(data + 8);
2524         lang_count = get_unaligned_le32(data + 12);
2525
2526         /* if one is zero the other must be zero */
2527         if (unlikely(!str_count != !lang_count))
2528                 goto error;
2529
2530         /* Do we have at least as many strings as descriptors need? */
2531         needed_count = ffs->strings_count;
2532         if (unlikely(str_count < needed_count))
2533                 goto error;
2534
2535         /*
2536          * If we don't need any strings just return and free all
2537          * memory.
2538          */
2539         if (!needed_count) {
2540                 kfree(_data);
2541                 return 0;
2542         }
2543
2544         /* Allocate everything in one chunk so there's less maintenance. */
2545         {
2546                 unsigned i = 0;
2547                 vla_group(d);
2548                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2549                         lang_count + 1);
2550                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2551                 vla_item(d, struct usb_string, strings,
2552                         lang_count*(needed_count+1));
2553
2554                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2555
2556                 if (unlikely(!vlabuf)) {
2557                         kfree(_data);
2558                         return -ENOMEM;
2559                 }
2560
2561                 /* Initialize the VLA pointers */
2562                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2563                 t = vla_ptr(vlabuf, d, stringtab);
2564                 i = lang_count;
2565                 do {
2566                         *stringtabs++ = t++;
2567                 } while (--i);
2568                 *stringtabs = NULL;
2569
2570                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2571                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2572                 t = vla_ptr(vlabuf, d, stringtab);
2573                 s = vla_ptr(vlabuf, d, strings);
2574         }
2575
2576         /* For each language */
2577         data += 16;
2578         len -= 16;
2579
2580         do { /* lang_count > 0 so we can use do-while */
2581                 unsigned needed = needed_count;
2582                 u32 str_per_lang = str_count;
2583
2584                 if (unlikely(len < 3))
2585                         goto error_free;
2586                 t->language = get_unaligned_le16(data);
2587                 t->strings  = s;
2588                 ++t;
2589
2590                 data += 2;
2591                 len -= 2;
2592
2593                 /* For each string */
2594                 do { /* str_count > 0 so we can use do-while */
2595                         size_t length = strnlen(data, len);
2596
2597                         if (unlikely(length == len))
2598                                 goto error_free;
2599
2600                         /*
2601                          * User may provide more strings then we need,
2602                          * if that's the case we simply ignore the
2603                          * rest
2604                          */
2605                         if (likely(needed)) {
2606                                 /*
2607                                  * s->id will be set while adding
2608                                  * function to configuration so for
2609                                  * now just leave garbage here.
2610                                  */
2611                                 s->s = data;
2612                                 --needed;
2613                                 ++s;
2614                         }
2615
2616                         data += length + 1;
2617                         len -= length + 1;
2618                 } while (--str_per_lang);
2619
2620                 s->id = 0;   /* terminator */
2621                 s->s = NULL;
2622                 ++s;
2623
2624         } while (--lang_count);
2625
2626         /* Some garbage left? */
2627         if (unlikely(len))
2628                 goto error_free;
2629
2630         /* Done! */
2631         ffs->stringtabs = stringtabs;
2632         ffs->raw_strings = _data;
2633
2634         return 0;
2635
2636 error_free:
2637         kfree(stringtabs);
2638 error:
2639         kfree(_data);
2640         return -EINVAL;
2641 }
2642
2643
2644 /* Events handling and management *******************************************/
2645
2646 static void __ffs_event_add(struct ffs_data *ffs,
2647                             enum usb_functionfs_event_type type)
2648 {
2649         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2650         int neg = 0;
2651
2652         /*
2653          * Abort any unhandled setup
2654          *
2655          * We do not need to worry about some cmpxchg() changing value
2656          * of ffs->setup_state without holding the lock because when
2657          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2658          * the source does nothing.
2659          */
2660         if (ffs->setup_state == FFS_SETUP_PENDING)
2661                 ffs->setup_state = FFS_SETUP_CANCELLED;
2662
2663         /*
2664          * Logic of this function guarantees that there are at most four pending
2665          * evens on ffs->ev.types queue.  This is important because the queue
2666          * has space for four elements only and __ffs_ep0_read_events function
2667          * depends on that limit as well.  If more event types are added, those
2668          * limits have to be revisited or guaranteed to still hold.
2669          */
2670         switch (type) {
2671         case FUNCTIONFS_RESUME:
2672                 rem_type2 = FUNCTIONFS_SUSPEND;
2673                 /* FALL THROUGH */
2674         case FUNCTIONFS_SUSPEND:
2675         case FUNCTIONFS_SETUP:
2676                 rem_type1 = type;
2677                 /* Discard all similar events */
2678                 break;
2679
2680         case FUNCTIONFS_BIND:
2681         case FUNCTIONFS_UNBIND:
2682         case FUNCTIONFS_DISABLE:
2683         case FUNCTIONFS_ENABLE:
2684                 /* Discard everything other then power management. */
2685                 rem_type1 = FUNCTIONFS_SUSPEND;
2686                 rem_type2 = FUNCTIONFS_RESUME;
2687                 neg = 1;
2688                 break;
2689
2690         default:
2691                 WARN(1, "%d: unknown event, this should not happen\n", type);
2692                 return;
2693         }
2694
2695         {
2696                 u8 *ev  = ffs->ev.types, *out = ev;
2697                 unsigned n = ffs->ev.count;
2698                 for (; n; --n, ++ev)
2699                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2700                                 *out++ = *ev;
2701                         else
2702                                 pr_vdebug("purging event %d\n", *ev);
2703                 ffs->ev.count = out - ffs->ev.types;
2704         }
2705
2706         pr_vdebug("adding event %d\n", type);
2707         ffs->ev.types[ffs->ev.count++] = type;
2708         wake_up_locked(&ffs->ev.waitq);
2709         if (ffs->ffs_eventfd)
2710                 eventfd_signal(ffs->ffs_eventfd, 1);
2711 }
2712
2713 static void ffs_event_add(struct ffs_data *ffs,
2714                           enum usb_functionfs_event_type type)
2715 {
2716         unsigned long flags;
2717         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2718         __ffs_event_add(ffs, type);
2719         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2720 }
2721
2722 /* Bind/unbind USB function hooks *******************************************/
2723
2724 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2725 {
2726         int i;
2727
2728         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2729                 if (ffs->eps_addrmap[i] == endpoint_address)
2730                         return i;
2731         return -ENOENT;
2732 }
2733
2734 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2735                                     struct usb_descriptor_header *desc,
2736                                     void *priv)
2737 {
2738         struct usb_endpoint_descriptor *ds = (void *)desc;
2739         struct ffs_function *func = priv;
2740         struct ffs_ep *ffs_ep;
2741         unsigned ep_desc_id;
2742         int idx;
2743         static const char *speed_names[] = { "full", "high", "super" };
2744
2745         if (type != FFS_DESCRIPTOR)
2746                 return 0;
2747
2748         /*
2749          * If ss_descriptors is not NULL, we are reading super speed
2750          * descriptors; if hs_descriptors is not NULL, we are reading high
2751          * speed descriptors; otherwise, we are reading full speed
2752          * descriptors.
2753          */
2754         if (func->function.ss_descriptors) {
2755                 ep_desc_id = 2;
2756                 func->function.ss_descriptors[(long)valuep] = desc;
2757         } else if (func->function.hs_descriptors) {
2758                 ep_desc_id = 1;
2759                 func->function.hs_descriptors[(long)valuep] = desc;
2760         } else {
2761                 ep_desc_id = 0;
2762                 func->function.fs_descriptors[(long)valuep]    = desc;
2763         }
2764
2765         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2766                 return 0;
2767
2768         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2769         if (idx < 0)
2770                 return idx;
2771
2772         ffs_ep = func->eps + idx;
2773
2774         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2775                 pr_err("two %sspeed descriptors for EP %d\n",
2776                           speed_names[ep_desc_id],
2777                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2778                 return -EINVAL;
2779         }
2780         ffs_ep->descs[ep_desc_id] = ds;
2781
2782         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2783         if (ffs_ep->ep) {
2784                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2785                 if (!ds->wMaxPacketSize)
2786                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2787         } else {
2788                 struct usb_request *req;
2789                 struct usb_ep *ep;
2790                 u8 bEndpointAddress;
2791
2792                 /*
2793                  * We back up bEndpointAddress because autoconfig overwrites
2794                  * it with physical endpoint address.
2795                  */
2796                 bEndpointAddress = ds->bEndpointAddress;
2797                 pr_vdebug("autoconfig\n");
2798                 ep = usb_ep_autoconfig(func->gadget, ds);
2799                 if (unlikely(!ep))
2800                         return -ENOTSUPP;
2801                 ep->driver_data = func->eps + idx;
2802
2803                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2804                 if (unlikely(!req))
2805                         return -ENOMEM;
2806
2807                 ffs_ep->ep  = ep;
2808                 ffs_ep->req = req;
2809                 func->eps_revmap[ds->bEndpointAddress &
2810                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2811                 /*
2812                  * If we use virtual address mapping, we restore
2813                  * original bEndpointAddress value.
2814                  */
2815                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2816                         ds->bEndpointAddress = bEndpointAddress;
2817         }
2818         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2819
2820         return 0;
2821 }
2822
2823 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2824                                    struct usb_descriptor_header *desc,
2825                                    void *priv)
2826 {
2827         struct ffs_function *func = priv;
2828         unsigned idx;
2829         u8 newValue;
2830
2831         switch (type) {
2832         default:
2833         case FFS_DESCRIPTOR:
2834                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2835                 return 0;
2836
2837         case FFS_INTERFACE:
2838                 idx = *valuep;
2839                 if (func->interfaces_nums[idx] < 0) {
2840                         int id = usb_interface_id(func->conf, &func->function);
2841                         if (unlikely(id < 0))
2842                                 return id;
2843                         func->interfaces_nums[idx] = id;
2844                 }
2845                 newValue = func->interfaces_nums[idx];
2846                 break;
2847
2848         case FFS_STRING:
2849                 /* String' IDs are allocated when fsf_data is bound to cdev */
2850                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2851                 break;
2852
2853         case FFS_ENDPOINT:
2854                 /*
2855                  * USB_DT_ENDPOINT are handled in
2856                  * __ffs_func_bind_do_descs().
2857                  */
2858                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2859                         return 0;
2860
2861                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2862                 if (unlikely(!func->eps[idx].ep))
2863                         return -EINVAL;
2864
2865                 {
2866                         struct usb_endpoint_descriptor **descs;
2867                         descs = func->eps[idx].descs;
2868                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2869                 }
2870                 break;
2871         }
2872
2873         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2874         *valuep = newValue;
2875         return 0;
2876 }
2877
2878 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2879                                       struct usb_os_desc_header *h, void *data,
2880                                       unsigned len, void *priv)
2881 {
2882         struct ffs_function *func = priv;
2883         u8 length = 0;
2884
2885         switch (type) {
2886         case FFS_OS_DESC_EXT_COMPAT: {
2887                 struct usb_ext_compat_desc *desc = data;
2888                 struct usb_os_desc_table *t;
2889
2890                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2891                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2892                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2893                        ARRAY_SIZE(desc->CompatibleID) +
2894                        ARRAY_SIZE(desc->SubCompatibleID));
2895                 length = sizeof(*desc);
2896         }
2897                 break;
2898         case FFS_OS_DESC_EXT_PROP: {
2899                 struct usb_ext_prop_desc *desc = data;
2900                 struct usb_os_desc_table *t;
2901                 struct usb_os_desc_ext_prop *ext_prop;
2902                 char *ext_prop_name;
2903                 char *ext_prop_data;
2904
2905                 t = &func->function.os_desc_table[h->interface];
2906                 t->if_id = func->interfaces_nums[h->interface];
2907
2908                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2909                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2910
2911                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2912                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2913                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2914                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2915                 length = ext_prop->name_len + ext_prop->data_len + 14;
2916
2917                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2918                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2919                         ext_prop->name_len;
2920
2921                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2922                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2923                         ext_prop->data_len;
2924                 memcpy(ext_prop_data,
2925                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2926                        ext_prop->data_len);
2927                 /* unicode data reported to the host as "WCHAR"s */
2928                 switch (ext_prop->type) {
2929                 case USB_EXT_PROP_UNICODE:
2930                 case USB_EXT_PROP_UNICODE_ENV:
2931                 case USB_EXT_PROP_UNICODE_LINK:
2932                 case USB_EXT_PROP_UNICODE_MULTI:
2933                         ext_prop->data_len *= 2;
2934                         break;
2935                 }
2936                 ext_prop->data = ext_prop_data;
2937
2938                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2939                        ext_prop->name_len);
2940                 /* property name reported to the host as "WCHAR"s */
2941                 ext_prop->name_len *= 2;
2942                 ext_prop->name = ext_prop_name;
2943
2944                 t->os_desc->ext_prop_len +=
2945                         ext_prop->name_len + ext_prop->data_len + 14;
2946                 ++t->os_desc->ext_prop_count;
2947                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2948         }
2949                 break;
2950         default:
2951                 pr_vdebug("unknown descriptor: %d\n", type);
2952         }
2953
2954         return length;
2955 }
2956
2957 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2958                                                 struct usb_configuration *c)
2959 {
2960         struct ffs_function *func = ffs_func_from_usb(f);
2961         struct f_fs_opts *ffs_opts =
2962                 container_of(f->fi, struct f_fs_opts, func_inst);
2963         struct ffs_data *ffs_data;
2964         int ret;
2965
2966         ENTER();
2967
2968         /*
2969          * Legacy gadget triggers binding in functionfs_ready_callback,
2970          * which already uses locking; taking the same lock here would
2971          * cause a deadlock.
2972          *
2973          * Configfs-enabled gadgets however do need ffs_dev_lock.
2974          */
2975         if (!ffs_opts->no_configfs)
2976                 ffs_dev_lock();
2977         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2978         ffs_data = ffs_opts->dev->ffs_data;
2979         if (!ffs_opts->no_configfs)
2980                 ffs_dev_unlock();
2981         if (ret)
2982                 return ERR_PTR(ret);
2983
2984         func->ffs = ffs_data;
2985         func->conf = c;
2986         func->gadget = c->cdev->gadget;
2987
2988         /*
2989          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2990          * configurations are bound in sequence with list_for_each_entry,
2991          * in each configuration its functions are bound in sequence
2992          * with list_for_each_entry, so we assume no race condition
2993          * with regard to ffs_opts->bound access
2994          */
2995         if (!ffs_opts->refcnt) {
2996                 ret = functionfs_bind(func->ffs, c->cdev);
2997                 if (ret)
2998                         return ERR_PTR(ret);
2999         }
3000         ffs_opts->refcnt++;
3001         func->function.strings = func->ffs->stringtabs;
3002
3003         return ffs_opts;
3004 }
3005
3006 static int _ffs_func_bind(struct usb_configuration *c,
3007                           struct usb_function *f)
3008 {
3009         struct ffs_function *func = ffs_func_from_usb(f);
3010         struct ffs_data *ffs = func->ffs;
3011
3012         const int full = !!func->ffs->fs_descs_count;
3013         const int high = !!func->ffs->hs_descs_count;
3014         const int super = !!func->ffs->ss_descs_count;
3015
3016         int fs_len, hs_len, ss_len, ret, i;
3017         struct ffs_ep *eps_ptr;
3018
3019         /* Make it a single chunk, less management later on */
3020         vla_group(d);
3021         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3022         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3023                 full ? ffs->fs_descs_count + 1 : 0);
3024         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3025                 high ? ffs->hs_descs_count + 1 : 0);
3026         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3027                 super ? ffs->ss_descs_count + 1 : 0);
3028         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3029         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3030                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3031         vla_item_with_sz(d, char[16], ext_compat,
3032                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3033         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3034                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3035         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3036                          ffs->ms_os_descs_ext_prop_count);
3037         vla_item_with_sz(d, char, ext_prop_name,
3038                          ffs->ms_os_descs_ext_prop_name_len);
3039         vla_item_with_sz(d, char, ext_prop_data,
3040                          ffs->ms_os_descs_ext_prop_data_len);
3041         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3042         char *vlabuf;
3043
3044         ENTER();
3045
3046         /* Has descriptors only for speeds gadget does not support */
3047         if (unlikely(!(full | high | super)))
3048                 return -ENOTSUPP;
3049
3050         /* Allocate a single chunk, less management later on */
3051         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3052         if (unlikely(!vlabuf))
3053                 return -ENOMEM;
3054
3055         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3056         ffs->ms_os_descs_ext_prop_name_avail =
3057                 vla_ptr(vlabuf, d, ext_prop_name);
3058         ffs->ms_os_descs_ext_prop_data_avail =
3059                 vla_ptr(vlabuf, d, ext_prop_data);
3060
3061         /* Copy descriptors  */
3062         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3063                ffs->raw_descs_length);
3064
3065         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3066         eps_ptr = vla_ptr(vlabuf, d, eps);
3067         for (i = 0; i < ffs->eps_count; i++)
3068                 eps_ptr[i].num = -1;
3069
3070         /* Save pointers
3071          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3072         */
3073         func->eps             = vla_ptr(vlabuf, d, eps);
3074         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3075
3076         /*
3077          * Go through all the endpoint descriptors and allocate
3078          * endpoints first, so that later we can rewrite the endpoint
3079          * numbers without worrying that it may be described later on.
3080          */
3081         if (likely(full)) {
3082                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3083                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3084                                       vla_ptr(vlabuf, d, raw_descs),
3085                                       d_raw_descs__sz,
3086                                       __ffs_func_bind_do_descs, func);
3087                 if (unlikely(fs_len < 0)) {
3088                         ret = fs_len;
3089                         goto error;
3090                 }
3091         } else {
3092                 fs_len = 0;
3093         }
3094
3095         if (likely(high)) {
3096                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3097                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3098                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3099                                       d_raw_descs__sz - fs_len,
3100                                       __ffs_func_bind_do_descs, func);
3101                 if (unlikely(hs_len < 0)) {
3102                         ret = hs_len;
3103                         goto error;
3104                 }
3105         } else {
3106                 hs_len = 0;
3107         }
3108
3109         if (likely(super)) {
3110                 func->function.ss_descriptors = func->function.ssp_descriptors =
3111                         vla_ptr(vlabuf, d, ss_descs);
3112                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3113                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3114                                 d_raw_descs__sz - fs_len - hs_len,
3115                                 __ffs_func_bind_do_descs, func);
3116                 if (unlikely(ss_len < 0)) {
3117                         ret = ss_len;
3118                         goto error;
3119                 }
3120         } else {
3121                 ss_len = 0;
3122         }
3123
3124         /*
3125          * Now handle interface numbers allocation and interface and
3126          * endpoint numbers rewriting.  We can do that in one go
3127          * now.
3128          */
3129         ret = ffs_do_descs(ffs->fs_descs_count +
3130                            (high ? ffs->hs_descs_count : 0) +
3131                            (super ? ffs->ss_descs_count : 0),
3132                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3133                            __ffs_func_bind_do_nums, func);
3134         if (unlikely(ret < 0))
3135                 goto error;
3136
3137         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3138         if (c->cdev->use_os_string) {
3139                 for (i = 0; i < ffs->interfaces_count; ++i) {
3140                         struct usb_os_desc *desc;
3141
3142                         desc = func->function.os_desc_table[i].os_desc =
3143                                 vla_ptr(vlabuf, d, os_desc) +
3144                                 i * sizeof(struct usb_os_desc);
3145                         desc->ext_compat_id =
3146                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3147                         INIT_LIST_HEAD(&desc->ext_prop);
3148                 }
3149                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3150                                       vla_ptr(vlabuf, d, raw_descs) +
3151                                       fs_len + hs_len + ss_len,
3152                                       d_raw_descs__sz - fs_len - hs_len -
3153                                       ss_len,
3154                                       __ffs_func_bind_do_os_desc, func);
3155                 if (unlikely(ret < 0))
3156                         goto error;
3157         }
3158         func->function.os_desc_n =
3159                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3160
3161         /* And we're done */
3162         ffs_event_add(ffs, FUNCTIONFS_BIND);
3163         return 0;
3164
3165 error:
3166         /* XXX Do we need to release all claimed endpoints here? */
3167         return ret;
3168 }
3169
3170 static int ffs_func_bind(struct usb_configuration *c,
3171                          struct usb_function *f)
3172 {
3173         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3174         struct ffs_function *func = ffs_func_from_usb(f);
3175         int ret;
3176
3177         if (IS_ERR(ffs_opts))
3178                 return PTR_ERR(ffs_opts);
3179
3180         ret = _ffs_func_bind(c, f);
3181         if (ret && !--ffs_opts->refcnt)
3182                 functionfs_unbind(func->ffs);
3183
3184         return ret;
3185 }
3186
3187
3188 /* Other USB function hooks *************************************************/
3189
3190 static void ffs_reset_work(struct work_struct *work)
3191 {
3192         struct ffs_data *ffs = container_of(work,
3193                 struct ffs_data, reset_work);
3194         ffs_data_reset(ffs);
3195 }
3196
3197 static int ffs_func_set_alt(struct usb_function *f,
3198                             unsigned interface, unsigned alt)
3199 {
3200         struct ffs_function *func = ffs_func_from_usb(f);
3201         struct ffs_data *ffs = func->ffs;
3202         int ret = 0, intf;
3203
3204         if (alt != (unsigned)-1) {
3205                 intf = ffs_func_revmap_intf(func, interface);
3206                 if (unlikely(intf < 0))
3207                         return intf;
3208         }
3209
3210         if (ffs->func)
3211                 ffs_func_eps_disable(ffs->func);
3212
3213         if (ffs->state == FFS_DEACTIVATED) {
3214                 ffs->state = FFS_CLOSING;
3215                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3216                 schedule_work(&ffs->reset_work);
3217                 return -ENODEV;
3218         }
3219
3220         if (ffs->state != FFS_ACTIVE)
3221                 return -ENODEV;
3222
3223         if (alt == (unsigned)-1) {
3224                 ffs->func = NULL;
3225                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3226                 return 0;
3227         }
3228
3229         ffs->func = func;
3230         ret = ffs_func_eps_enable(func);
3231         if (likely(ret >= 0))
3232                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3233         return ret;
3234 }
3235
3236 static void ffs_func_disable(struct usb_function *f)
3237 {
3238         ffs_func_set_alt(f, 0, (unsigned)-1);
3239 }
3240
3241 static int ffs_func_setup(struct usb_function *f,
3242                           const struct usb_ctrlrequest *creq)
3243 {
3244         struct ffs_function *func = ffs_func_from_usb(f);
3245         struct ffs_data *ffs = func->ffs;
3246         unsigned long flags;
3247         int ret;
3248
3249         ENTER();
3250
3251         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3252         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3253         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3254         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3255         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3256
3257         /*
3258          * Most requests directed to interface go through here
3259          * (notable exceptions are set/get interface) so we need to
3260          * handle them.  All other either handled by composite or
3261          * passed to usb_configuration->setup() (if one is set).  No
3262          * matter, we will handle requests directed to endpoint here
3263          * as well (as it's straightforward).  Other request recipient
3264          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3265          * is being used.
3266          */
3267         if (ffs->state != FFS_ACTIVE)
3268                 return -ENODEV;
3269
3270         switch (creq->bRequestType & USB_RECIP_MASK) {
3271         case USB_RECIP_INTERFACE:
3272                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3273                 if (unlikely(ret < 0))
3274                         return ret;
3275                 break;
3276
3277         case USB_RECIP_ENDPOINT:
3278                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3279                 if (unlikely(ret < 0))
3280                         return ret;
3281                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3282                         ret = func->ffs->eps_addrmap[ret];
3283                 break;
3284
3285         default:
3286                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3287                         ret = le16_to_cpu(creq->wIndex);
3288                 else
3289                         return -EOPNOTSUPP;
3290         }
3291
3292         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3293         ffs->ev.setup = *creq;
3294         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3295         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3296         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3297
3298         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3299 }
3300
3301 static bool ffs_func_req_match(struct usb_function *f,
3302                                const struct usb_ctrlrequest *creq,
3303                                bool config0)
3304 {
3305         struct ffs_function *func = ffs_func_from_usb(f);
3306
3307         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3308                 return false;
3309
3310         switch (creq->bRequestType & USB_RECIP_MASK) {
3311         case USB_RECIP_INTERFACE:
3312                 return (ffs_func_revmap_intf(func,
3313                                              le16_to_cpu(creq->wIndex)) >= 0);
3314         case USB_RECIP_ENDPOINT:
3315                 return (ffs_func_revmap_ep(func,
3316                                            le16_to_cpu(creq->wIndex)) >= 0);
3317         default:
3318                 return (bool) (func->ffs->user_flags &
3319                                FUNCTIONFS_ALL_CTRL_RECIP);
3320         }
3321 }
3322
3323 static void ffs_func_suspend(struct usb_function *f)
3324 {
3325         ENTER();
3326         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3327 }
3328
3329 static void ffs_func_resume(struct usb_function *f)
3330 {
3331         ENTER();
3332         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3333 }
3334
3335
3336 /* Endpoint and interface numbers reverse mapping ***************************/
3337
3338 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3339 {
3340         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3341         return num ? num : -EDOM;
3342 }
3343
3344 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3345 {
3346         short *nums = func->interfaces_nums;
3347         unsigned count = func->ffs->interfaces_count;
3348
3349         for (; count; --count, ++nums) {
3350                 if (*nums >= 0 && *nums == intf)
3351                         return nums - func->interfaces_nums;
3352         }
3353
3354         return -EDOM;
3355 }
3356
3357
3358 /* Devices management *******************************************************/
3359
3360 static LIST_HEAD(ffs_devices);
3361
3362 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3363 {
3364         struct ffs_dev *dev;
3365
3366         if (!name)
3367                 return NULL;
3368
3369         list_for_each_entry(dev, &ffs_devices, entry) {
3370                 if (strcmp(dev->name, name) == 0)
3371                         return dev;
3372         }
3373
3374         return NULL;
3375 }
3376
3377 /*
3378  * ffs_lock must be taken by the caller of this function
3379  */
3380 static struct ffs_dev *_ffs_get_single_dev(void)
3381 {
3382         struct ffs_dev *dev;
3383
3384         if (list_is_singular(&ffs_devices)) {
3385                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3386                 if (dev->single)
3387                         return dev;
3388         }
3389
3390         return NULL;
3391 }
3392
3393 /*
3394  * ffs_lock must be taken by the caller of this function
3395  */
3396 static struct ffs_dev *_ffs_find_dev(const char *name)
3397 {
3398         struct ffs_dev *dev;
3399
3400         dev = _ffs_get_single_dev();
3401         if (dev)
3402                 return dev;
3403
3404         return _ffs_do_find_dev(name);
3405 }
3406
3407 /* Configfs support *********************************************************/
3408
3409 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3410 {
3411         return container_of(to_config_group(item), struct f_fs_opts,
3412                             func_inst.group);
3413 }
3414
3415 static void ffs_attr_release(struct config_item *item)
3416 {
3417         struct f_fs_opts *opts = to_ffs_opts(item);
3418
3419         usb_put_function_instance(&opts->func_inst);
3420 }
3421
3422 static struct configfs_item_operations ffs_item_ops = {
3423         .release        = ffs_attr_release,
3424 };
3425
3426 static const struct config_item_type ffs_func_type = {
3427         .ct_item_ops    = &ffs_item_ops,
3428         .ct_owner       = THIS_MODULE,
3429 };
3430
3431
3432 /* Function registration interface ******************************************/
3433
3434 static void ffs_free_inst(struct usb_function_instance *f)
3435 {
3436         struct f_fs_opts *opts;
3437
3438         opts = to_f_fs_opts(f);
3439         ffs_release_dev(opts->dev);
3440         ffs_dev_lock();
3441         _ffs_free_dev(opts->dev);
3442         ffs_dev_unlock();
3443         kfree(opts);
3444 }
3445
3446 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3447 {
3448         if (strlen(name) >= FIELD_SIZEOF(struct ffs_dev, name))
3449                 return -ENAMETOOLONG;
3450         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3451 }
3452
3453 static struct usb_function_instance *ffs_alloc_inst(void)
3454 {
3455         struct f_fs_opts *opts;
3456         struct ffs_dev *dev;
3457
3458         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3459         if (!opts)
3460                 return ERR_PTR(-ENOMEM);
3461
3462         opts->func_inst.set_inst_name = ffs_set_inst_name;
3463         opts->func_inst.free_func_inst = ffs_free_inst;
3464         ffs_dev_lock();
3465         dev = _ffs_alloc_dev();
3466         ffs_dev_unlock();
3467         if (IS_ERR(dev)) {
3468                 kfree(opts);
3469                 return ERR_CAST(dev);
3470         }
3471         opts->dev = dev;
3472         dev->opts = opts;
3473
3474         config_group_init_type_name(&opts->func_inst.group, "",
3475                                     &ffs_func_type);
3476         return &opts->func_inst;
3477 }
3478
3479 static void ffs_free(struct usb_function *f)
3480 {
3481         kfree(ffs_func_from_usb(f));
3482 }
3483
3484 static void ffs_func_unbind(struct usb_configuration *c,
3485                             struct usb_function *f)
3486 {
3487         struct ffs_function *func = ffs_func_from_usb(f);
3488         struct ffs_data *ffs = func->ffs;
3489         struct f_fs_opts *opts =
3490                 container_of(f->fi, struct f_fs_opts, func_inst);
3491         struct ffs_ep *ep = func->eps;
3492         unsigned count = ffs->eps_count;
3493         unsigned long flags;
3494
3495         ENTER();
3496         if (ffs->func == func) {
3497                 ffs_func_eps_disable(func);
3498                 ffs->func = NULL;
3499         }
3500
3501         /* Drain any pending AIO completions */
3502         drain_workqueue(ffs->io_completion_wq);
3503
3504         if (!--opts->refcnt)
3505                 functionfs_unbind(ffs);
3506
3507         /* cleanup after autoconfig */
3508         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3509         while (count--) {
3510                 if (ep->ep && ep->req)
3511                         usb_ep_free_request(ep->ep, ep->req);
3512                 ep->req = NULL;
3513                 ++ep;
3514         }
3515         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3516         kfree(func->eps);
3517         func->eps = NULL;
3518         /*
3519          * eps, descriptors and interfaces_nums are allocated in the
3520          * same chunk so only one free is required.
3521          */
3522         func->function.fs_descriptors = NULL;
3523         func->function.hs_descriptors = NULL;
3524         func->function.ss_descriptors = NULL;
3525         func->function.ssp_descriptors = NULL;
3526         func->interfaces_nums = NULL;
3527
3528         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3529 }
3530
3531 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3532 {
3533         struct ffs_function *func;
3534
3535         ENTER();
3536
3537         func = kzalloc(sizeof(*func), GFP_KERNEL);
3538         if (unlikely(!func))
3539                 return ERR_PTR(-ENOMEM);
3540
3541         func->function.name    = "Function FS Gadget";
3542
3543         func->function.bind    = ffs_func_bind;
3544         func->function.unbind  = ffs_func_unbind;
3545         func->function.set_alt = ffs_func_set_alt;
3546         func->function.disable = ffs_func_disable;
3547         func->function.setup   = ffs_func_setup;
3548         func->function.req_match = ffs_func_req_match;
3549         func->function.suspend = ffs_func_suspend;
3550         func->function.resume  = ffs_func_resume;
3551         func->function.free_func = ffs_free;
3552
3553         return &func->function;
3554 }
3555
3556 /*
3557  * ffs_lock must be taken by the caller of this function
3558  */
3559 static struct ffs_dev *_ffs_alloc_dev(void)
3560 {
3561         struct ffs_dev *dev;
3562         int ret;
3563
3564         if (_ffs_get_single_dev())
3565                         return ERR_PTR(-EBUSY);
3566
3567         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3568         if (!dev)
3569                 return ERR_PTR(-ENOMEM);
3570
3571         if (list_empty(&ffs_devices)) {
3572                 ret = functionfs_init();
3573                 if (ret) {
3574                         kfree(dev);
3575                         return ERR_PTR(ret);
3576                 }
3577         }
3578
3579         list_add(&dev->entry, &ffs_devices);
3580
3581         return dev;
3582 }
3583
3584 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3585 {
3586         struct ffs_dev *existing;
3587         int ret = 0;
3588
3589         ffs_dev_lock();
3590
3591         existing = _ffs_do_find_dev(name);
3592         if (!existing)
3593                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3594         else if (existing != dev)
3595                 ret = -EBUSY;
3596
3597         ffs_dev_unlock();
3598
3599         return ret;
3600 }
3601 EXPORT_SYMBOL_GPL(ffs_name_dev);
3602
3603 int ffs_single_dev(struct ffs_dev *dev)
3604 {
3605         int ret;
3606
3607         ret = 0;
3608         ffs_dev_lock();
3609
3610         if (!list_is_singular(&ffs_devices))
3611                 ret = -EBUSY;
3612         else
3613                 dev->single = true;
3614
3615         ffs_dev_unlock();
3616         return ret;
3617 }
3618 EXPORT_SYMBOL_GPL(ffs_single_dev);
3619
3620 /*
3621  * ffs_lock must be taken by the caller of this function
3622  */
3623 static void _ffs_free_dev(struct ffs_dev *dev)
3624 {
3625         list_del(&dev->entry);
3626
3627         kfree(dev);
3628         if (list_empty(&ffs_devices))
3629                 functionfs_cleanup();
3630 }
3631
3632 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data)
3633 {
3634         int ret = 0;
3635         struct ffs_dev *ffs_dev;
3636
3637         ENTER();
3638         ffs_dev_lock();
3639
3640         ffs_dev = _ffs_find_dev(dev_name);
3641         if (!ffs_dev) {
3642                 ret = -ENOENT;
3643         } else if (ffs_dev->mounted) {
3644                 ret = -EBUSY;
3645         } else if (ffs_dev->ffs_acquire_dev_callback &&
3646                    ffs_dev->ffs_acquire_dev_callback(ffs_dev)) {
3647                 ret = -ENOENT;
3648         } else {
3649                 ffs_dev->mounted = true;
3650                 ffs_dev->ffs_data = ffs_data;
3651                 ffs_data->private_data = ffs_dev;
3652         }
3653
3654         ffs_dev_unlock();
3655         return ret;
3656 }
3657
3658 static void ffs_release_dev(struct ffs_dev *ffs_dev)
3659 {
3660         ENTER();
3661         ffs_dev_lock();
3662
3663         if (ffs_dev && ffs_dev->mounted) {
3664                 ffs_dev->mounted = false;
3665                 if (ffs_dev->ffs_data) {
3666                         ffs_dev->ffs_data->private_data = NULL;
3667                         ffs_dev->ffs_data = NULL;
3668                 }
3669
3670                 if (ffs_dev->ffs_release_dev_callback)
3671                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3672         }
3673
3674         ffs_dev_unlock();
3675 }
3676
3677 static int ffs_ready(struct ffs_data *ffs)
3678 {
3679         struct ffs_dev *ffs_obj;
3680         int ret = 0;
3681
3682         ENTER();
3683         ffs_dev_lock();
3684
3685         ffs_obj = ffs->private_data;
3686         if (!ffs_obj) {
3687                 ret = -EINVAL;
3688                 goto done;
3689         }
3690         if (WARN_ON(ffs_obj->desc_ready)) {
3691                 ret = -EBUSY;
3692                 goto done;
3693         }
3694
3695         ffs_obj->desc_ready = true;
3696
3697         if (ffs_obj->ffs_ready_callback) {
3698                 ret = ffs_obj->ffs_ready_callback(ffs);
3699                 if (ret)
3700                         goto done;
3701         }
3702
3703         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3704 done:
3705         ffs_dev_unlock();
3706         return ret;
3707 }
3708
3709 static void ffs_closed(struct ffs_data *ffs)
3710 {
3711         struct ffs_dev *ffs_obj;
3712         struct f_fs_opts *opts;
3713         struct config_item *ci;
3714
3715         ENTER();
3716         ffs_dev_lock();
3717
3718         ffs_obj = ffs->private_data;
3719         if (!ffs_obj)
3720                 goto done;
3721
3722         ffs_obj->desc_ready = false;
3723
3724         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3725             ffs_obj->ffs_closed_callback)
3726                 ffs_obj->ffs_closed_callback(ffs);
3727
3728         if (ffs_obj->opts)
3729                 opts = ffs_obj->opts;
3730         else
3731                 goto done;
3732
3733         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3734             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3735                 goto done;
3736
3737         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3738         ffs_dev_unlock();
3739
3740         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3741                 unregister_gadget_item(ci);
3742         return;
3743 done:
3744         ffs_dev_unlock();
3745 }
3746
3747 /* Misc helper functions ****************************************************/
3748
3749 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3750 {
3751         return nonblock
3752                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3753                 : mutex_lock_interruptible(mutex);
3754 }
3755
3756 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3757 {
3758         char *data;
3759
3760         if (unlikely(!len))
3761                 return NULL;
3762
3763         data = kmalloc(len, GFP_KERNEL);
3764         if (unlikely(!data))
3765                 return ERR_PTR(-ENOMEM);
3766
3767         if (unlikely(copy_from_user(data, buf, len))) {
3768                 kfree(data);
3769                 return ERR_PTR(-EFAULT);
3770         }
3771
3772         pr_vdebug("Buffer from user space:\n");
3773         ffs_dump_mem("", data, len);
3774
3775         return data;
3776 }
3777
3778 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3779 MODULE_LICENSE("GPL");
3780 MODULE_AUTHOR("Michal Nazarewicz");