drivers/usb/gadget/function/f_fs.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_fs.c -- user mode file system API for USB composite function controllers
   4  *
   5  * Copyright (C) 2010 Samsung Electronics
   6  * Author: Michal Nazarewicz <mina86@mina86.com>
   7  *
   8  * Based on inode.c (GadgetFS) which was:
   9  * Copyright (C) 2003-2004 David Brownell
  10  * Copyright (C) 2003 Agilent Technologies
  11  */
  12
  13
  14 /* #define DEBUG */
  15 /* #define VERBOSE_DEBUG */
  16
  17 #include <linux/blkdev.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/export.h>
  20 #include <linux/fs_parser.h>
  21 #include <linux/hid.h>
  22 #include <linux/mm.h>
  23 #include <linux/module.h>
  24 #include <linux/scatterlist.h>
  25 #include <linux/sched/signal.h>
  26 #include <linux/uio.h>
  27 #include <linux/vmalloc.h>
  28 #include <asm/unaligned.h>
  29
  30 #include <linux/usb/ccid.h>
  31 #include <linux/usb/composite.h>
  32 #include <linux/usb/functionfs.h>
  33
  34 #include <linux/aio.h>
  35 #include <linux/kthread.h>
  36 #include <linux/poll.h>
  37 #include <linux/eventfd.h>
  38
  39 #include "u_fs.h"
  40 #include "u_f.h"
  41 #include "u_os_desc.h"
  42 #include "configfs.h"
  43
  44 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  45
  46 /* Reference counter handling */
  47 static void ffs_data_get(struct ffs_data *ffs);
  48 static void ffs_data_put(struct ffs_data *ffs);
  49 /* Creates new ffs_data object. */
  50 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  51         __attribute__((malloc));
  52
  53 /* Opened counter handling. */
  54 static void ffs_data_opened(struct ffs_data *ffs);
  55 static void ffs_data_closed(struct ffs_data *ffs);
  56
  57 /* Called with ffs->mutex held; take over ownership of data. */
  58 static int __must_check
  59 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  60 static int __must_check
  61 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  62
  63
  64 /* The function structure ***************************************************/
  65
  66 struct ffs_ep;
  67
  68 struct ffs_function {
  69         struct usb_configuration        *conf;
  70         struct usb_gadget               *gadget;
  71         struct ffs_data                 *ffs;
  72
  73         struct ffs_ep                   *eps;
  74         u8                              eps_revmap[16];
  75         short                           *interfaces_nums;
  76
  77         struct usb_function             function;
  78 };
  79
  80
  81 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  82 {
  83         return container_of(f, struct ffs_function, function);
  84 }
  85
  86
  87 static inline enum ffs_setup_state
  88 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  89 {
  90         return (enum ffs_setup_state)
  91                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  92 }
  93
  94
  95 static void ffs_func_eps_disable(struct ffs_function *func);
  96 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  97
  98 static int ffs_func_bind(struct usb_configuration *,
  99                          struct usb_function *);
 100 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 101 static void ffs_func_disable(struct usb_function *);
 102 static int ffs_func_setup(struct usb_function *,
 103                           const struct usb_ctrlrequest *);
 104 static bool ffs_func_req_match(struct usb_function *,
 105                                const struct usb_ctrlrequest *,
 106                                bool config0);
 107 static void ffs_func_suspend(struct usb_function *);
 108 static void ffs_func_resume(struct usb_function *);
 109
 110
 111 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 112 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 113
 114
 115 /* The endpoints structures *************************************************/
 116
 117 struct ffs_ep {
 118         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 119         struct usb_request              *req;   /* P: epfile->mutex */
 120
 121         /* [0]: full speed, [1]: high speed, [2]: super speed */
 122         struct usb_endpoint_descriptor  *descs[3];
 123
 124         u8                              num;
 125
 126         int                             status; /* P: epfile->mutex */
 127 };
 128
 129 struct ffs_epfile {
 130         /* Protects ep->ep and ep->req. */
 131         struct mutex                    mutex;
 132
 133         struct ffs_data                 *ffs;
 134         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 135
 136         struct dentry                   *dentry;
 137
 138         /*
 139          * Buffer for holding data from partial reads which may happen since
 140          * we’re rounding user read requests to a multiple of a max packet size.
 141          *
 142          * The pointer is initialised with NULL value and may be set by
 143          * __ffs_epfile_read_data function to point to a temporary buffer.
 144          *
 145          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 146          * data from said buffer and eventually free it.  Importantly, while the
 147          * function is using the buffer, it sets the pointer to NULL.  This is
 148          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 149          * can never run concurrently (they are synchronised by epfile->mutex)
 150          * so the latter will not assign a new value to the pointer.
 151          *
 152          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 153          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 154          * value is crux of the synchronisation between ffs_func_eps_disable and
 155          * __ffs_epfile_read_data.
 156          *
 157          * Once __ffs_epfile_read_data is about to finish it will try to set the
 158          * pointer back to its old value (as described above), but seeing as the
 159          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 160          * the buffer.
 161          *
 162          * == State transitions ==
 163          *
 164          * • ptr == NULL:  (initial state)
 165          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 166          *   ◦ __ffs_epfile_read_buffered:    nop
 167          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 168          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 169          * • ptr == DROP:
 170          *   ◦ __ffs_epfile_read_buffer_free: nop
 171          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 172          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 173          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 174          * • ptr == buf:
 175          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 176          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 177          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 178          *                                    is always called first
 179          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 180          * • ptr == NULL and reading:
 181          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 182          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 183          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 184          *   ◦ reading finishes and …
 185          *     … all data read:               free buf, go to ptr == NULL
 186          *     … otherwise:                   go to ptr == buf and reading
 187          * • ptr == DROP and reading:
 188          *   ◦ __ffs_epfile_read_buffer_free: nop
 189          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 190          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 191          *   ◦ reading finishes:              free buf, go to ptr == DROP
 192          */
 193         struct ffs_buffer               *read_buffer;
 194 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 195
 196         char                            name[5];
 197
 198         unsigned char                   in;     /* P: ffs->eps_lock */
 199         unsigned char                   isoc;   /* P: ffs->eps_lock */
 200
 201         unsigned char                   _pad;
 202 };
 203
 204 struct ffs_buffer {
 205         size_t length;
 206         char *data;
 207         char storage[];
 208 };
 209
 210 /*  ffs_io_data structure ***************************************************/
 211
 212 struct ffs_io_data {
 213         bool aio;
 214         bool read;
 215
 216         struct kiocb *kiocb;
 217         struct iov_iter data;
 218         const void *to_free;
 219         char *buf;
 220
 221         struct mm_struct *mm;
 222         struct work_struct work;
 223
 224         struct usb_ep *ep;
 225         struct usb_request *req;
 226         struct sg_table sgt;
 227         bool use_sg;
 228
 229         struct ffs_data *ffs;
 230 };
 231
 232 struct ffs_desc_helper {
 233         struct ffs_data *ffs;
 234         unsigned interfaces_count;
 235         unsigned eps_count;
 236 };
 237
 238 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 239 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 240
 241 static struct dentry *
 242 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 243                    const struct file_operations *fops);
 244
 245 /* Devices management *******************************************************/
 246
 247 DEFINE_MUTEX(ffs_lock);
 248 EXPORT_SYMBOL_GPL(ffs_lock);
 249
 250 static struct ffs_dev *_ffs_find_dev(const char *name);
 251 static struct ffs_dev *_ffs_alloc_dev(void);
 252 static void _ffs_free_dev(struct ffs_dev *dev);
 253 static void *ffs_acquire_dev(const char *dev_name);
 254 static void ffs_release_dev(struct ffs_data *ffs_data);
 255 static int ffs_ready(struct ffs_data *ffs);
 256 static void ffs_closed(struct ffs_data *ffs);
 257
 258 /* Misc helper functions ****************************************************/
 259
 260 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 261         __attribute__((warn_unused_result, nonnull));
 262 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 263         __attribute__((warn_unused_result, nonnull));
 264
 265
 266 /* Control file aka ep0 *****************************************************/
 267
 268 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 269 {
 270         struct ffs_data *ffs = req->context;
 271
 272         complete(&ffs->ep0req_completion);
 273 }
 274
 275 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 276         __releases(&ffs->ev.waitq.lock)
 277 {
 278         struct usb_request *req = ffs->ep0req;
 279         int ret;
 280
 281         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 282
 283         spin_unlock_irq(&ffs->ev.waitq.lock);
 284
 285         req->buf      = data;
 286         req->length   = len;
 287
 288         /*
 289          * UDC layer requires to provide a buffer even for ZLP, but should
 290          * not use it at all. Let's provide some poisoned pointer to catch
 291          * possible bug in the driver.
 292          */
 293         if (req->buf == NULL)
 294                 req->buf = (void *)0xDEADBABE;
 295
 296         reinit_completion(&ffs->ep0req_completion);
 297
 298         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 299         if (unlikely(ret < 0))
 300                 return ret;
 301
 302         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 303         if (unlikely(ret)) {
 304                 usb_ep_dequeue(ffs->gadget->ep0, req);
 305                 return -EINTR;
 306         }
 307
 308         ffs->setup_state = FFS_NO_SETUP;
 309         return req->status ? req->status : req->actual;
 310 }
 311
 312 static int __ffs_ep0_stall(struct ffs_data *ffs)
 313 {
 314         if (ffs->ev.can_stall) {
 315                 pr_vdebug("ep0 stall\n");
 316                 usb_ep_set_halt(ffs->gadget->ep0);
 317                 ffs->setup_state = FFS_NO_SETUP;
 318                 return -EL2HLT;
 319         } else {
 320                 pr_debug("bogus ep0 stall!\n");
 321                 return -ESRCH;
 322         }
 323 }
 324
 325 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 326                              size_t len, loff_t *ptr)
 327 {
 328         struct ffs_data *ffs = file->private_data;
 329         ssize_t ret;
 330         char *data;
 331
 332         ENTER();
 333
 334         /* Fast check if setup was canceled */
 335         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 336                 return -EIDRM;
 337
 338         /* Acquire mutex */
 339         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 340         if (unlikely(ret < 0))
 341                 return ret;
 342
 343         /* Check state */
 344         switch (ffs->state) {
 345         case FFS_READ_DESCRIPTORS:
 346         case FFS_READ_STRINGS:
 347                 /* Copy data */
 348                 if (unlikely(len < 16)) {
 349                         ret = -EINVAL;
 350                         break;
 351                 }
 352
 353                 data = ffs_prepare_buffer(buf, len);
 354                 if (IS_ERR(data)) {
 355                         ret = PTR_ERR(data);
 356                         break;
 357                 }
 358
 359                 /* Handle data */
 360                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 361                         pr_info("read descriptors\n");
 362                         ret = __ffs_data_got_descs(ffs, data, len);
 363                         if (unlikely(ret < 0))
 364                                 break;
 365
 366                         ffs->state = FFS_READ_STRINGS;
 367                         ret = len;
 368                 } else {
 369                         pr_info("read strings\n");
 370                         ret = __ffs_data_got_strings(ffs, data, len);
 371                         if (unlikely(ret < 0))
 372                                 break;
 373
 374                         ret = ffs_epfiles_create(ffs);
 375                         if (unlikely(ret)) {
 376                                 ffs->state = FFS_CLOSING;
 377                                 break;
 378                         }
 379
 380                         ffs->state = FFS_ACTIVE;
 381                         mutex_unlock(&ffs->mutex);
 382
 383                         ret = ffs_ready(ffs);
 384                         if (unlikely(ret < 0)) {
 385                                 ffs->state = FFS_CLOSING;
 386                                 return ret;
 387                         }
 388
 389                         return len;
 390                 }
 391                 break;
 392
 393         case FFS_ACTIVE:
 394                 data = NULL;
 395                 /*
 396                  * We're called from user space, we can use _irq
 397                  * rather then _irqsave
 398                  */
 399                 spin_lock_irq(&ffs->ev.waitq.lock);
 400                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 401                 case FFS_SETUP_CANCELLED:
 402                         ret = -EIDRM;
 403                         goto done_spin;
 404
 405                 case FFS_NO_SETUP:
 406                         ret = -ESRCH;
 407                         goto done_spin;
 408
 409                 case FFS_SETUP_PENDING:
 410                         break;
 411                 }
 412
 413                 /* FFS_SETUP_PENDING */
 414                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 415                         spin_unlock_irq(&ffs->ev.waitq.lock);
 416                         ret = __ffs_ep0_stall(ffs);
 417                         break;
 418                 }
 419
 420                 /* FFS_SETUP_PENDING and not stall */
 421                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 422
 423                 spin_unlock_irq(&ffs->ev.waitq.lock);
 424
 425                 data = ffs_prepare_buffer(buf, len);
 426                 if (IS_ERR(data)) {
 427                         ret = PTR_ERR(data);
 428                         break;
 429                 }
 430
 431                 spin_lock_irq(&ffs->ev.waitq.lock);
 432
 433                 /*
 434                  * We are guaranteed to be still in FFS_ACTIVE state
 435                  * but the state of setup could have changed from
 436                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 437                  * to check for that.  If that happened we copied data
 438                  * from user space in vain but it's unlikely.
 439                  *
 440                  * For sure we are not in FFS_NO_SETUP since this is
 441                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 442                  * transition can be performed and it's protected by
 443                  * mutex.
 444                  */
 445                 if (ffs_setup_state_clear_cancelled(ffs) ==
 446                     FFS_SETUP_CANCELLED) {
 447                         ret = -EIDRM;
 448 done_spin:
 449                         spin_unlock_irq(&ffs->ev.waitq.lock);
 450                 } else {
 451                         /* unlocks spinlock */
 452                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 453                 }
 454                 kfree(data);
 455                 break;
 456
 457         default:
 458                 ret = -EBADFD;
 459                 break;
 460         }
 461
 462         mutex_unlock(&ffs->mutex);
 463         return ret;
 464 }
 465
 466 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 467 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 468                                      size_t n)
 469         __releases(&ffs->ev.waitq.lock)
 470 {
 471         /*
 472          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 473          * size of ffs->ev.types array (which is four) so that's how much space
 474          * we reserve.
 475          */
 476         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 477         const size_t size = n * sizeof *events;
 478         unsigned i = 0;
 479
 480         memset(events, 0, size);
 481
 482         do {
 483                 events[i].type = ffs->ev.types[i];
 484                 if (events[i].type == FUNCTIONFS_SETUP) {
 485                         events[i].u.setup = ffs->ev.setup;
 486                         ffs->setup_state = FFS_SETUP_PENDING;
 487                 }
 488         } while (++i < n);
 489
 490         ffs->ev.count -= n;
 491         if (ffs->ev.count)
 492                 memmove(ffs->ev.types, ffs->ev.types + n,
 493                         ffs->ev.count * sizeof *ffs->ev.types);
 494
 495         spin_unlock_irq(&ffs->ev.waitq.lock);
 496         mutex_unlock(&ffs->mutex);
 497
 498         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 499 }
 500
 501 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 502                             size_t len, loff_t *ptr)
 503 {
 504         struct ffs_data *ffs = file->private_data;
 505         char *data = NULL;
 506         size_t n;
 507         int ret;
 508
 509         ENTER();
 510
 511         /* Fast check if setup was canceled */
 512         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 513                 return -EIDRM;
 514
 515         /* Acquire mutex */
 516         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 517         if (unlikely(ret < 0))
 518                 return ret;
 519
 520         /* Check state */
 521         if (ffs->state != FFS_ACTIVE) {
 522                 ret = -EBADFD;
 523                 goto done_mutex;
 524         }
 525
 526         /*
 527          * We're called from user space, we can use _irq rather then
 528          * _irqsave
 529          */
 530         spin_lock_irq(&ffs->ev.waitq.lock);
 531
 532         switch (ffs_setup_state_clear_cancelled(ffs)) {
 533         case FFS_SETUP_CANCELLED:
 534                 ret = -EIDRM;
 535                 break;
 536
 537         case FFS_NO_SETUP:
 538                 n = len / sizeof(struct usb_functionfs_event);
 539                 if (unlikely(!n)) {
 540                         ret = -EINVAL;
 541                         break;
 542                 }
 543
 544                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 545                         ret = -EAGAIN;
 546                         break;
 547                 }
 548
 549                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 550                                                         ffs->ev.count)) {
 551                         ret = -EINTR;
 552                         break;
 553                 }
 554
 555                 /* unlocks spinlock */
 556                 return __ffs_ep0_read_events(ffs, buf,
 557                                              min(n, (size_t)ffs->ev.count));
 558
 559         case FFS_SETUP_PENDING:
 560                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 561                         spin_unlock_irq(&ffs->ev.waitq.lock);
 562                         ret = __ffs_ep0_stall(ffs);
 563                         goto done_mutex;
 564                 }
 565
 566                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 567
 568                 spin_unlock_irq(&ffs->ev.waitq.lock);
 569
 570                 if (likely(len)) {
 571                         data = kmalloc(len, GFP_KERNEL);
 572                         if (unlikely(!data)) {
 573                                 ret = -ENOMEM;
 574                                 goto done_mutex;
 575                         }
 576                 }
 577
 578                 spin_lock_irq(&ffs->ev.waitq.lock);
 579
 580                 /* See ffs_ep0_write() */
 581                 if (ffs_setup_state_clear_cancelled(ffs) ==
 582                     FFS_SETUP_CANCELLED) {
 583                         ret = -EIDRM;
 584                         break;
 585                 }
 586
 587                 /* unlocks spinlock */
 588                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 589                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 590                         ret = -EFAULT;
 591                 goto done_mutex;
 592
 593         default:
 594                 ret = -EBADFD;
 595                 break;
 596         }
 597
 598         spin_unlock_irq(&ffs->ev.waitq.lock);
 599 done_mutex:
 600         mutex_unlock(&ffs->mutex);
 601         kfree(data);
 602         return ret;
 603 }
 604
 605 static int ffs_ep0_open(struct inode *inode, struct file *file)
 606 {
 607         struct ffs_data *ffs = inode->i_private;
 608
 609         ENTER();
 610
 611         if (unlikely(ffs->state == FFS_CLOSING))
 612                 return -EBUSY;
 613
 614         file->private_data = ffs;
 615         ffs_data_opened(ffs);
 616
 617         return 0;
 618 }
 619
 620 static int ffs_ep0_release(struct inode *inode, struct file *file)
 621 {
 622         struct ffs_data *ffs = file->private_data;
 623
 624         ENTER();
 625
 626         ffs_data_closed(ffs);
 627
 628         return 0;
 629 }
 630
 631 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 632 {
 633         struct ffs_data *ffs = file->private_data;
 634         struct usb_gadget *gadget = ffs->gadget;
 635         long ret;
 636
 637         ENTER();
 638
 639         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 640                 struct ffs_function *func = ffs->func;
 641                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 642         } else if (gadget && gadget->ops->ioctl) {
 643                 ret = gadget->ops->ioctl(gadget, code, value);
 644         } else {
 645                 ret = -ENOTTY;
 646         }
 647
 648         return ret;
 649 }
 650
 651 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 652 {
 653         struct ffs_data *ffs = file->private_data;
 654         __poll_t mask = EPOLLWRNORM;
 655         int ret;
 656
 657         poll_wait(file, &ffs->ev.waitq, wait);
 658
 659         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 660         if (unlikely(ret < 0))
 661                 return mask;
 662
 663         switch (ffs->state) {
 664         case FFS_READ_DESCRIPTORS:
 665         case FFS_READ_STRINGS:
 666                 mask |= EPOLLOUT;
 667                 break;
 668
 669         case FFS_ACTIVE:
 670                 switch (ffs->setup_state) {
 671                 case FFS_NO_SETUP:
 672                         if (ffs->ev.count)
 673                                 mask |= EPOLLIN;
 674                         break;
 675
 676                 case FFS_SETUP_PENDING:
 677                 case FFS_SETUP_CANCELLED:
 678                         mask |= (EPOLLIN | EPOLLOUT);
 679                         break;
 680                 }
 681         case FFS_CLOSING:
 682                 break;
 683         case FFS_DEACTIVATED:
 684                 break;
 685         }
 686
 687         mutex_unlock(&ffs->mutex);
 688
 689         return mask;
 690 }
 691
 692 static const struct file_operations ffs_ep0_operations = {
 693         .llseek =       no_llseek,
 694
 695         .open =         ffs_ep0_open,
 696         .write =        ffs_ep0_write,
 697         .read =         ffs_ep0_read,
 698         .release =      ffs_ep0_release,
 699         .unlocked_ioctl =       ffs_ep0_ioctl,
 700         .poll =         ffs_ep0_poll,
 701 };
 702
 703
 704 /* "Normal" endpoints operations ********************************************/
 705
 706 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 707 {
 708         ENTER();
 709         if (likely(req->context)) {
 710                 struct ffs_ep *ep = _ep->driver_data;
 711                 ep->status = req->status ? req->status : req->actual;
 712                 complete(req->context);
 713         }
 714 }
 715
 716 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 717 {
 718         ssize_t ret = copy_to_iter(data, data_len, iter);
 719         if (likely(ret == data_len))
 720                 return ret;
 721
 722         if (unlikely(iov_iter_count(iter)))
 723                 return -EFAULT;
 724
 725         /*
 726          * Dear user space developer!
 727          *
 728          * TL;DR: To stop getting below error message in your kernel log, change
 729          * user space code using functionfs to align read buffers to a max
 730          * packet size.
 731          *
 732          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 733          * packet size.  When unaligned buffer is passed to functionfs, it
 734          * internally uses a larger, aligned buffer so that such UDCs are happy.
 735          *
 736          * Unfortunately, this means that host may send more data than was
 737          * requested in read(2) system call.  f_fs doesn’t know what to do with
 738          * that excess data so it simply drops it.
 739          *
 740          * Was the buffer aligned in the first place, no such problem would
 741          * happen.
 742          *
 743          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 744          * by splitting a request into multiple parts.  This splitting may still
 745          * be a problem though so it’s likely best to align the buffer
 746          * regardless of it being AIO or not..
 747          *
 748          * This only affects OUT endpoints, i.e. reading data with a read(2),
 749          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 750          * affected.
 751          */
 752         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 753                "Align read buffer size to max packet size to avoid the problem.\n",
 754                data_len, ret);
 755
 756         return ret;
 757 }
 758
 759 /*
 760  * allocate a virtually contiguous buffer and create a scatterlist describing it
 761  * @sg_table    - pointer to a place to be filled with sg_table contents
 762  * @size        - required buffer size
 763  */
 764 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 765 {
 766         struct page **pages;
 767         void *vaddr, *ptr;
 768         unsigned int n_pages;
 769         int i;
 770
 771         vaddr = vmalloc(sz);
 772         if (!vaddr)
 773                 return NULL;
 774
 775         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 776         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 777         if (!pages) {
 778                 vfree(vaddr);
 779
 780                 return NULL;
 781         }
 782         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 783                 pages[i] = vmalloc_to_page(ptr);
 784
 785         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 786                 kvfree(pages);
 787                 vfree(vaddr);
 788
 789                 return NULL;
 790         }
 791         kvfree(pages);
 792
 793         return vaddr;
 794 }
 795
 796 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 797         size_t data_len)
 798 {
 799         if (io_data->use_sg)
 800                 return ffs_build_sg_list(&io_data->sgt, data_len);
 801
 802         return kmalloc(data_len, GFP_KERNEL);
 803 }
 804
 805 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 806 {
 807         if (!io_data->buf)
 808                 return;
 809
 810         if (io_data->use_sg) {
 811                 sg_free_table(&io_data->sgt);
 812                 vfree(io_data->buf);
 813         } else {
 814                 kfree(io_data->buf);
 815         }
 816 }
 817
 818 static void ffs_user_copy_worker(struct work_struct *work)
 819 {
 820         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 821                                                    work);
 822         int ret = io_data->req->status ? io_data->req->status :
 823                                          io_data->req->actual;
 824         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 825
 826         if (io_data->read && ret > 0) {
 827                 kthread_use_mm(io_data->mm);
 828                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 829                 kthread_unuse_mm(io_data->mm);
 830         }
 831
 832         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 833
 834         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 835                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 836
 837         usb_ep_free_request(io_data->ep, io_data->req);
 838
 839         if (io_data->read)
 840                 kfree(io_data->to_free);
 841         ffs_free_buffer(io_data);
 842         kfree(io_data);
 843 }
 844
 845 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 846                                          struct usb_request *req)
 847 {
 848         struct ffs_io_data *io_data = req->context;
 849         struct ffs_data *ffs = io_data->ffs;
 850
 851         ENTER();
 852
 853         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 854         queue_work(ffs->io_completion_wq, &io_data->work);
 855 }
 856
 857 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 858 {
 859         /*
 860          * See comment in struct ffs_epfile for full read_buffer pointer
 861          * synchronisation story.
 862          */
 863         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 864         if (buf && buf != READ_BUFFER_DROP)
 865                 kfree(buf);
 866 }
 867
 868 /* Assumes epfile->mutex is held. */
 869 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 870                                           struct iov_iter *iter)
 871 {
 872         /*
 873          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 874          * the buffer while we are using it.  See comment in struct ffs_epfile
 875          * for full read_buffer pointer synchronisation story.
 876          */
 877         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 878         ssize_t ret;
 879         if (!buf || buf == READ_BUFFER_DROP)
 880                 return 0;
 881
 882         ret = copy_to_iter(buf->data, buf->length, iter);
 883         if (buf->length == ret) {
 884                 kfree(buf);
 885                 return ret;
 886         }
 887
 888         if (unlikely(iov_iter_count(iter))) {
 889                 ret = -EFAULT;
 890         } else {
 891                 buf->length -= ret;
 892                 buf->data += ret;
 893         }
 894
 895         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 896                 kfree(buf);
 897
 898         return ret;
 899 }
 900
 901 /* Assumes epfile->mutex is held. */
 902 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 903                                       void *data, int data_len,
 904                                       struct iov_iter *iter)
 905 {
 906         struct ffs_buffer *buf;
 907
 908         ssize_t ret = copy_to_iter(data, data_len, iter);
 909         if (likely(data_len == ret))
 910                 return ret;
 911
 912         if (unlikely(iov_iter_count(iter)))
 913                 return -EFAULT;
 914
 915         /* See ffs_copy_to_iter for more context. */
 916         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 917                 data_len, ret);
 918
 919         data_len -= ret;
 920         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 921         if (!buf)
 922                 return -ENOMEM;
 923         buf->length = data_len;
 924         buf->data = buf->storage;
 925         memcpy(buf->storage, data + ret, data_len);
 926
 927         /*
 928          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 929          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 930          * in struct ffs_epfile for full read_buffer pointer synchronisation
 931          * story.
 932          */
 933         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 934                 kfree(buf);
 935
 936         return ret;
 937 }
 938
 939 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 940 {
 941         struct ffs_epfile *epfile = file->private_data;
 942         struct usb_request *req;
 943         struct ffs_ep *ep;
 944         char *data = NULL;
 945         ssize_t ret, data_len = -EINVAL;
 946         int halt;
 947
 948         /* Are we still active? */
 949         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 950                 return -ENODEV;
 951
 952         /* Wait for endpoint to be enabled */
 953         ep = epfile->ep;
 954         if (!ep) {
 955                 if (file->f_flags & O_NONBLOCK)
 956                         return -EAGAIN;
 957
 958                 ret = wait_event_interruptible(
 959                                 epfile->ffs->wait, (ep = epfile->ep));
 960                 if (ret)
 961                         return -EINTR;
 962         }
 963
 964         /* Do we halt? */
 965         halt = (!io_data->read == !epfile->in);
 966         if (halt && epfile->isoc)
 967                 return -EINVAL;
 968
 969         /* We will be using request and read_buffer */
 970         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 971         if (unlikely(ret))
 972                 goto error;
 973
 974         /* Allocate & copy */
 975         if (!halt) {
 976                 struct usb_gadget *gadget;
 977
 978                 /*
 979                  * Do we have buffered data from previous partial read?  Check
 980                  * that for synchronous case only because we do not have
 981                  * facility to ‘wake up’ a pending asynchronous read and push
 982                  * buffered data to it which we would need to make things behave
 983                  * consistently.
 984                  */
 985                 if (!io_data->aio && io_data->read) {
 986                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 987                         if (ret)
 988                                 goto error_mutex;
 989                 }
 990
 991                 /*
 992                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 993                  * before the waiting completes, so do not assign to 'gadget'
 994                  * earlier
 995                  */
 996                 gadget = epfile->ffs->gadget;
 997
 998                 spin_lock_irq(&epfile->ffs->eps_lock);
 999                 /* In the meantime, endpoint got disabled or changed. */
1000                 if (epfile->ep != ep) {
1001                         ret = -ESHUTDOWN;
1002                         goto error_lock;
1003                 }
1004                 data_len = iov_iter_count(&io_data->data);
1005                 /*
1006                  * Controller may require buffer size to be aligned to
1007                  * maxpacketsize of an out endpoint.
1008                  */
1009                 if (io_data->read)
1010                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1011
1012                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1013                 spin_unlock_irq(&epfile->ffs->eps_lock);
1014
1015                 data = ffs_alloc_buffer(io_data, data_len);
1016                 if (unlikely(!data)) {
1017                         ret = -ENOMEM;
1018                         goto error_mutex;
1019                 }
1020                 if (!io_data->read &&
1021                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1022                         ret = -EFAULT;
1023                         goto error_mutex;
1024                 }
1025         }
1026
1027         spin_lock_irq(&epfile->ffs->eps_lock);
1028
1029         if (epfile->ep != ep) {
1030                 /* In the meantime, endpoint got disabled or changed. */
1031                 ret = -ESHUTDOWN;
1032         } else if (halt) {
1033                 ret = usb_ep_set_halt(ep->ep);
1034                 if (!ret)
1035                         ret = -EBADMSG;
1036         } else if (unlikely(data_len == -EINVAL)) {
1037                 /*
1038                  * Sanity Check: even though data_len can't be used
1039                  * uninitialized at the time I write this comment, some
1040                  * compilers complain about this situation.
1041                  * In order to keep the code clean from warnings, data_len is
1042                  * being initialized to -EINVAL during its declaration, which
1043                  * means we can't rely on compiler anymore to warn no future
1044                  * changes won't result in data_len being used uninitialized.
1045                  * For such reason, we're adding this redundant sanity check
1046                  * here.
1047                  */
1048                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1049                 ret = -EINVAL;
1050         } else if (!io_data->aio) {
1051                 DECLARE_COMPLETION_ONSTACK(done);
1052                 bool interrupted = false;
1053
1054                 req = ep->req;
1055                 if (io_data->use_sg) {
1056                         req->buf = NULL;
1057                         req->sg = io_data->sgt.sgl;
1058                         req->num_sgs = io_data->sgt.nents;
1059                 } else {
1060                         req->buf = data;
1061                         req->num_sgs = 0;
1062                 }
1063                 req->length = data_len;
1064
1065                 io_data->buf = data;
1066
1067                 req->context  = &done;
1068                 req->complete = ffs_epfile_io_complete;
1069
1070                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1071                 if (unlikely(ret < 0))
1072                         goto error_lock;
1073
1074                 spin_unlock_irq(&epfile->ffs->eps_lock);
1075
1076                 if (unlikely(wait_for_completion_interruptible(&done))) {
1077                         /*
1078                          * To avoid race condition with ffs_epfile_io_complete,
1079                          * dequeue the request first then check
1080                          * status. usb_ep_dequeue API should guarantee no race
1081                          * condition with req->complete callback.
1082                          */
1083                         usb_ep_dequeue(ep->ep, req);
1084                         wait_for_completion(&done);
1085                         interrupted = ep->status < 0;
1086                 }
1087
1088                 if (interrupted)
1089                         ret = -EINTR;
1090                 else if (io_data->read && ep->status > 0)
1091                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1092                                                      &io_data->data);
1093                 else
1094                         ret = ep->status;
1095                 goto error_mutex;
1096         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1097                 ret = -ENOMEM;
1098         } else {
1099                 if (io_data->use_sg) {
1100                         req->buf = NULL;
1101                         req->sg = io_data->sgt.sgl;
1102                         req->num_sgs = io_data->sgt.nents;
1103                 } else {
1104                         req->buf = data;
1105                         req->num_sgs = 0;
1106                 }
1107                 req->length = data_len;
1108
1109                 io_data->buf = data;
1110                 io_data->ep = ep->ep;
1111                 io_data->req = req;
1112                 io_data->ffs = epfile->ffs;
1113
1114                 req->context  = io_data;
1115                 req->complete = ffs_epfile_async_io_complete;
1116
1117                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1118                 if (unlikely(ret)) {
1119                         io_data->req = NULL;
1120                         usb_ep_free_request(ep->ep, req);
1121                         goto error_lock;
1122                 }
1123
1124                 ret = -EIOCBQUEUED;
1125                 /*
1126                  * Do not kfree the buffer in this function.  It will be freed
1127                  * by ffs_user_copy_worker.
1128                  */
1129                 data = NULL;
1130         }
1131
1132 error_lock:
1133         spin_unlock_irq(&epfile->ffs->eps_lock);
1134 error_mutex:
1135         mutex_unlock(&epfile->mutex);
1136 error:
1137         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1138                 ffs_free_buffer(io_data);
1139         return ret;
1140 }
1141
1142 static int
1143 ffs_epfile_open(struct inode *inode, struct file *file)
1144 {
1145         struct ffs_epfile *epfile = inode->i_private;
1146
1147         ENTER();
1148
1149         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1150                 return -ENODEV;
1151
1152         file->private_data = epfile;
1153         ffs_data_opened(epfile->ffs);
1154
1155         return 0;
1156 }
1157
1158 static int ffs_aio_cancel(struct kiocb *kiocb)
1159 {
1160         struct ffs_io_data *io_data = kiocb->private;
1161         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1162         unsigned long flags;
1163         int value;
1164
1165         ENTER();
1166
1167         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1168
1169         if (likely(io_data && io_data->ep && io_data->req))
1170                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1171         else
1172                 value = -EINVAL;
1173
1174         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1175
1176         return value;
1177 }
1178
1179 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1180 {
1181         struct ffs_io_data io_data, *p = &io_data;
1182         ssize_t res;
1183
1184         ENTER();
1185
1186         if (!is_sync_kiocb(kiocb)) {
1187                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1188                 if (unlikely(!p))
1189                         return -ENOMEM;
1190                 p->aio = true;
1191         } else {
1192                 memset(p, 0, sizeof(*p));
1193                 p->aio = false;
1194         }
1195
1196         p->read = false;
1197         p->kiocb = kiocb;
1198         p->data = *from;
1199         p->mm = current->mm;
1200
1201         kiocb->private = p;
1202
1203         if (p->aio)
1204                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1205
1206         res = ffs_epfile_io(kiocb->ki_filp, p);
1207         if (res == -EIOCBQUEUED)
1208                 return res;
1209         if (p->aio)
1210                 kfree(p);
1211         else
1212                 *from = p->data;
1213         return res;
1214 }
1215
1216 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1217 {
1218         struct ffs_io_data io_data, *p = &io_data;
1219         ssize_t res;
1220
1221         ENTER();
1222
1223         if (!is_sync_kiocb(kiocb)) {
1224                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1225                 if (unlikely(!p))
1226                         return -ENOMEM;
1227                 p->aio = true;
1228         } else {
1229                 memset(p, 0, sizeof(*p));
1230                 p->aio = false;
1231         }
1232
1233         p->read = true;
1234         p->kiocb = kiocb;
1235         if (p->aio) {
1236                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1237                 if (!p->to_free) {
1238                         kfree(p);
1239                         return -ENOMEM;
1240                 }
1241         } else {
1242                 p->data = *to;
1243                 p->to_free = NULL;
1244         }
1245         p->mm = current->mm;
1246
1247         kiocb->private = p;
1248
1249         if (p->aio)
1250                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1251
1252         res = ffs_epfile_io(kiocb->ki_filp, p);
1253         if (res == -EIOCBQUEUED)
1254                 return res;
1255
1256         if (p->aio) {
1257                 kfree(p->to_free);
1258                 kfree(p);
1259         } else {
1260                 *to = p->data;
1261         }
1262         return res;
1263 }
1264
1265 static int
1266 ffs_epfile_release(struct inode *inode, struct file *file)
1267 {
1268         struct ffs_epfile *epfile = inode->i_private;
1269
1270         ENTER();
1271
1272         __ffs_epfile_read_buffer_free(epfile);
1273         ffs_data_closed(epfile->ffs);
1274
1275         return 0;
1276 }
1277
1278 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1279                              unsigned long value)
1280 {
1281         struct ffs_epfile *epfile = file->private_data;
1282         struct ffs_ep *ep;
1283         int ret;
1284
1285         ENTER();
1286
1287         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1288                 return -ENODEV;
1289
1290         /* Wait for endpoint to be enabled */
1291         ep = epfile->ep;
1292         if (!ep) {
1293                 if (file->f_flags & O_NONBLOCK)
1294                         return -EAGAIN;
1295
1296                 ret = wait_event_interruptible(
1297                                 epfile->ffs->wait, (ep = epfile->ep));
1298                 if (ret)
1299                         return -EINTR;
1300         }
1301
1302         spin_lock_irq(&epfile->ffs->eps_lock);
1303
1304         /* In the meantime, endpoint got disabled or changed. */
1305         if (epfile->ep != ep) {
1306                 spin_unlock_irq(&epfile->ffs->eps_lock);
1307                 return -ESHUTDOWN;
1308         }
1309
1310         switch (code) {
1311         case FUNCTIONFS_FIFO_STATUS:
1312                 ret = usb_ep_fifo_status(epfile->ep->ep);
1313                 break;
1314         case FUNCTIONFS_FIFO_FLUSH:
1315                 usb_ep_fifo_flush(epfile->ep->ep);
1316                 ret = 0;
1317                 break;
1318         case FUNCTIONFS_CLEAR_HALT:
1319                 ret = usb_ep_clear_halt(epfile->ep->ep);
1320                 break;
1321         case FUNCTIONFS_ENDPOINT_REVMAP:
1322                 ret = epfile->ep->num;
1323                 break;
1324         case FUNCTIONFS_ENDPOINT_DESC:
1325         {
1326                 int desc_idx;
1327                 struct usb_endpoint_descriptor *desc;
1328
1329                 switch (epfile->ffs->gadget->speed) {
1330                 case USB_SPEED_SUPER:
1331                         desc_idx = 2;
1332                         break;
1333                 case USB_SPEED_HIGH:
1334                         desc_idx = 1;
1335                         break;
1336                 default:
1337                         desc_idx = 0;
1338                 }
1339                 desc = epfile->ep->descs[desc_idx];
1340
1341                 spin_unlock_irq(&epfile->ffs->eps_lock);
1342                 ret = copy_to_user((void __user *)value, desc, desc->bLength);
1343                 if (ret)
1344                         ret = -EFAULT;
1345                 return ret;
1346         }
1347         default:
1348                 ret = -ENOTTY;
1349         }
1350         spin_unlock_irq(&epfile->ffs->eps_lock);
1351
1352         return ret;
1353 }
1354
1355 static const struct file_operations ffs_epfile_operations = {
1356         .llseek =       no_llseek,
1357
1358         .open =         ffs_epfile_open,
1359         .write_iter =   ffs_epfile_write_iter,
1360         .read_iter =    ffs_epfile_read_iter,
1361         .release =      ffs_epfile_release,
1362         .unlocked_ioctl =       ffs_epfile_ioctl,
1363         .compat_ioctl = compat_ptr_ioctl,
1364 };
1365
1366
1367 /* File system and super block operations ***********************************/
1368
1369 /*
1370  * Mounting the file system creates a controller file, used first for
1371  * function configuration then later for event monitoring.
1372  */
1373
1374 static struct inode *__must_check
1375 ffs_sb_make_inode(struct super_block *sb, void *data,
1376                   const struct file_operations *fops,
1377                   const struct inode_operations *iops,
1378                   struct ffs_file_perms *perms)
1379 {
1380         struct inode *inode;
1381
1382         ENTER();
1383
1384         inode = new_inode(sb);
1385
1386         if (likely(inode)) {
1387                 struct timespec64 ts = current_time(inode);
1388
1389                 inode->i_ino     = get_next_ino();
1390                 inode->i_mode    = perms->mode;
1391                 inode->i_uid     = perms->uid;
1392                 inode->i_gid     = perms->gid;
1393                 inode->i_atime   = ts;
1394                 inode->i_mtime   = ts;
1395                 inode->i_ctime   = ts;
1396                 inode->i_private = data;
1397                 if (fops)
1398                         inode->i_fop = fops;
1399                 if (iops)
1400                         inode->i_op  = iops;
1401         }
1402
1403         return inode;
1404 }
1405
1406 /* Create "regular" file */
1407 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1408                                         const char *name, void *data,
1409                                         const struct file_operations *fops)
1410 {
1411         struct ffs_data *ffs = sb->s_fs_info;
1412         struct dentry   *dentry;
1413         struct inode    *inode;
1414
1415         ENTER();
1416
1417         dentry = d_alloc_name(sb->s_root, name);
1418         if (unlikely(!dentry))
1419                 return NULL;
1420
1421         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1422         if (unlikely(!inode)) {
1423                 dput(dentry);
1424                 return NULL;
1425         }
1426
1427         d_add(dentry, inode);
1428         return dentry;
1429 }
1430
1431 /* Super block */
1432 static const struct super_operations ffs_sb_operations = {
1433         .statfs =       simple_statfs,
1434         .drop_inode =   generic_delete_inode,
1435 };
1436
1437 struct ffs_sb_fill_data {
1438         struct ffs_file_perms perms;
1439         umode_t root_mode;
1440         const char *dev_name;
1441         bool no_disconnect;
1442         struct ffs_data *ffs_data;
1443 };
1444
1445 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1446 {
1447         struct ffs_sb_fill_data *data = fc->fs_private;
1448         struct inode    *inode;
1449         struct ffs_data *ffs = data->ffs_data;
1450
1451         ENTER();
1452
1453         ffs->sb              = sb;
1454         data->ffs_data       = NULL;
1455         sb->s_fs_info        = ffs;
1456         sb->s_blocksize      = PAGE_SIZE;
1457         sb->s_blocksize_bits = PAGE_SHIFT;
1458         sb->s_magic          = FUNCTIONFS_MAGIC;
1459         sb->s_op             = &ffs_sb_operations;
1460         sb->s_time_gran      = 1;
1461
1462         /* Root inode */
1463         data->perms.mode = data->root_mode;
1464         inode = ffs_sb_make_inode(sb, NULL,
1465                                   &simple_dir_operations,
1466                                   &simple_dir_inode_operations,
1467                                   &data->perms);
1468         sb->s_root = d_make_root(inode);
1469         if (unlikely(!sb->s_root))
1470                 return -ENOMEM;
1471
1472         /* EP0 file */
1473         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1474                                          &ffs_ep0_operations)))
1475                 return -ENOMEM;
1476
1477         return 0;
1478 }
1479
1480 enum {
1481         Opt_no_disconnect,
1482         Opt_rmode,
1483         Opt_fmode,
1484         Opt_mode,
1485         Opt_uid,
1486         Opt_gid,
1487 };
1488
1489 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1490         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1491         fsparam_u32     ("rmode",               Opt_rmode),
1492         fsparam_u32     ("fmode",               Opt_fmode),
1493         fsparam_u32     ("mode",                Opt_mode),
1494         fsparam_u32     ("uid",                 Opt_uid),
1495         fsparam_u32     ("gid",                 Opt_gid),
1496         {}
1497 };
1498
1499 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1500 {
1501         struct ffs_sb_fill_data *data = fc->fs_private;
1502         struct fs_parse_result result;
1503         int opt;
1504
1505         ENTER();
1506
1507         opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1508         if (opt < 0)
1509                 return opt;
1510
1511         switch (opt) {
1512         case Opt_no_disconnect:
1513                 data->no_disconnect = result.boolean;
1514                 break;
1515         case Opt_rmode:
1516                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1517                 break;
1518         case Opt_fmode:
1519                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1520                 break;
1521         case Opt_mode:
1522                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1523                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1524                 break;
1525
1526         case Opt_uid:
1527                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1528                 if (!uid_valid(data->perms.uid))
1529                         goto unmapped_value;
1530                 break;
1531         case Opt_gid:
1532                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1533                 if (!gid_valid(data->perms.gid))
1534                         goto unmapped_value;
1535                 break;
1536
1537         default:
1538                 return -ENOPARAM;
1539         }
1540
1541         return 0;
1542
1543 unmapped_value:
1544         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1545 }
1546
1547 /*
1548  * Set up the superblock for a mount.
1549  */
1550 static int ffs_fs_get_tree(struct fs_context *fc)
1551 {
1552         struct ffs_sb_fill_data *ctx = fc->fs_private;
1553         void *ffs_dev;
1554         struct ffs_data *ffs;
1555
1556         ENTER();
1557
1558         if (!fc->source)
1559                 return invalf(fc, "No source specified");
1560
1561         ffs = ffs_data_new(fc->source);
1562         if (unlikely(!ffs))
1563                 return -ENOMEM;
1564         ffs->file_perms = ctx->perms;
1565         ffs->no_disconnect = ctx->no_disconnect;
1566
1567         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1568         if (unlikely(!ffs->dev_name)) {
1569                 ffs_data_put(ffs);
1570                 return -ENOMEM;
1571         }
1572
1573         ffs_dev = ffs_acquire_dev(ffs->dev_name);
1574         if (IS_ERR(ffs_dev)) {
1575                 ffs_data_put(ffs);
1576                 return PTR_ERR(ffs_dev);
1577         }
1578
1579         ffs->private_data = ffs_dev;
1580         ctx->ffs_data = ffs;
1581         return get_tree_nodev(fc, ffs_sb_fill);
1582 }
1583
1584 static void ffs_fs_free_fc(struct fs_context *fc)
1585 {
1586         struct ffs_sb_fill_data *ctx = fc->fs_private;
1587
1588         if (ctx) {
1589                 if (ctx->ffs_data) {
1590                         ffs_release_dev(ctx->ffs_data);
1591                         ffs_data_put(ctx->ffs_data);
1592                 }
1593
1594                 kfree(ctx);
1595         }
1596 }
1597
1598 static const struct fs_context_operations ffs_fs_context_ops = {
1599         .free           = ffs_fs_free_fc,
1600         .parse_param    = ffs_fs_parse_param,
1601         .get_tree       = ffs_fs_get_tree,
1602 };
1603
1604 static int ffs_fs_init_fs_context(struct fs_context *fc)
1605 {
1606         struct ffs_sb_fill_data *ctx;
1607
1608         ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1609         if (!ctx)
1610                 return -ENOMEM;
1611
1612         ctx->perms.mode = S_IFREG | 0600;
1613         ctx->perms.uid = GLOBAL_ROOT_UID;
1614         ctx->perms.gid = GLOBAL_ROOT_GID;
1615         ctx->root_mode = S_IFDIR | 0500;
1616         ctx->no_disconnect = false;
1617
1618         fc->fs_private = ctx;
1619         fc->ops = &ffs_fs_context_ops;
1620         return 0;
1621 }
1622
1623 static void
1624 ffs_fs_kill_sb(struct super_block *sb)
1625 {
1626         ENTER();
1627
1628         kill_litter_super(sb);
1629         if (sb->s_fs_info) {
1630                 ffs_release_dev(sb->s_fs_info);
1631                 ffs_data_closed(sb->s_fs_info);
1632         }
1633 }
1634
1635 static struct file_system_type ffs_fs_type = {
1636         .owner          = THIS_MODULE,
1637         .name           = "functionfs",
1638         .init_fs_context = ffs_fs_init_fs_context,
1639         .parameters     = ffs_fs_fs_parameters,
1640         .kill_sb        = ffs_fs_kill_sb,
1641 };
1642 MODULE_ALIAS_FS("functionfs");
1643
1644
1645 /* Driver's main init/cleanup functions *************************************/
1646
1647 static int functionfs_init(void)
1648 {
1649         int ret;
1650
1651         ENTER();
1652
1653         ret = register_filesystem(&ffs_fs_type);
1654         if (likely(!ret))
1655                 pr_info("file system registered\n");
1656         else
1657                 pr_err("failed registering file system (%d)\n", ret);
1658
1659         return ret;
1660 }
1661
1662 static void functionfs_cleanup(void)
1663 {
1664         ENTER();
1665
1666         pr_info("unloading\n");
1667         unregister_filesystem(&ffs_fs_type);
1668 }
1669
1670
1671 /* ffs_data and ffs_function construction and destruction code **************/
1672
1673 static void ffs_data_clear(struct ffs_data *ffs);
1674 static void ffs_data_reset(struct ffs_data *ffs);
1675
1676 static void ffs_data_get(struct ffs_data *ffs)
1677 {
1678         ENTER();
1679
1680         refcount_inc(&ffs->ref);
1681 }
1682
1683 static void ffs_data_opened(struct ffs_data *ffs)
1684 {
1685         ENTER();
1686
1687         refcount_inc(&ffs->ref);
1688         if (atomic_add_return(1, &ffs->opened) == 1 &&
1689                         ffs->state == FFS_DEACTIVATED) {
1690                 ffs->state = FFS_CLOSING;
1691                 ffs_data_reset(ffs);
1692         }
1693 }
1694
1695 static void ffs_data_put(struct ffs_data *ffs)
1696 {
1697         ENTER();
1698
1699         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1700                 pr_info("%s(): freeing\n", __func__);
1701                 ffs_data_clear(ffs);
1702                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1703                        swait_active(&ffs->ep0req_completion.wait) ||
1704                        waitqueue_active(&ffs->wait));
1705                 destroy_workqueue(ffs->io_completion_wq);
1706                 kfree(ffs->dev_name);
1707                 kfree(ffs);
1708         }
1709 }
1710
1711 static void ffs_data_closed(struct ffs_data *ffs)
1712 {
1713         ENTER();
1714
1715         if (atomic_dec_and_test(&ffs->opened)) {
1716                 if (ffs->no_disconnect) {
1717                         ffs->state = FFS_DEACTIVATED;
1718                         if (ffs->epfiles) {
1719                                 ffs_epfiles_destroy(ffs->epfiles,
1720                                                    ffs->eps_count);
1721                                 ffs->epfiles = NULL;
1722                         }
1723                         if (ffs->setup_state == FFS_SETUP_PENDING)
1724                                 __ffs_ep0_stall(ffs);
1725                 } else {
1726                         ffs->state = FFS_CLOSING;
1727                         ffs_data_reset(ffs);
1728                 }
1729         }
1730         if (atomic_read(&ffs->opened) < 0) {
1731                 ffs->state = FFS_CLOSING;
1732                 ffs_data_reset(ffs);
1733         }
1734
1735         ffs_data_put(ffs);
1736 }
1737
1738 static struct ffs_data *ffs_data_new(const char *dev_name)
1739 {
1740         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1741         if (unlikely(!ffs))
1742                 return NULL;
1743
1744         ENTER();
1745
1746         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1747         if (!ffs->io_completion_wq) {
1748                 kfree(ffs);
1749                 return NULL;
1750         }
1751
1752         refcount_set(&ffs->ref, 1);
1753         atomic_set(&ffs->opened, 0);
1754         ffs->state = FFS_READ_DESCRIPTORS;
1755         mutex_init(&ffs->mutex);
1756         spin_lock_init(&ffs->eps_lock);
1757         init_waitqueue_head(&ffs->ev.waitq);
1758         init_waitqueue_head(&ffs->wait);
1759         init_completion(&ffs->ep0req_completion);
1760
1761         /* XXX REVISIT need to update it in some places, or do we? */
1762         ffs->ev.can_stall = 1;
1763
1764         return ffs;
1765 }
1766
1767 static void ffs_data_clear(struct ffs_data *ffs)
1768 {
1769         ENTER();
1770
1771         ffs_closed(ffs);
1772
1773         BUG_ON(ffs->gadget);
1774
1775         if (ffs->epfiles)
1776                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1777
1778         if (ffs->ffs_eventfd)
1779                 eventfd_ctx_put(ffs->ffs_eventfd);
1780
1781         kfree(ffs->raw_descs_data);
1782         kfree(ffs->raw_strings);
1783         kfree(ffs->stringtabs);
1784 }
1785
1786 static void ffs_data_reset(struct ffs_data *ffs)
1787 {
1788         ENTER();
1789
1790         ffs_data_clear(ffs);
1791
1792         ffs->epfiles = NULL;
1793         ffs->raw_descs_data = NULL;
1794         ffs->raw_descs = NULL;
1795         ffs->raw_strings = NULL;
1796         ffs->stringtabs = NULL;
1797
1798         ffs->raw_descs_length = 0;
1799         ffs->fs_descs_count = 0;
1800         ffs->hs_descs_count = 0;
1801         ffs->ss_descs_count = 0;
1802
1803         ffs->strings_count = 0;
1804         ffs->interfaces_count = 0;
1805         ffs->eps_count = 0;
1806
1807         ffs->ev.count = 0;
1808
1809         ffs->state = FFS_READ_DESCRIPTORS;
1810         ffs->setup_state = FFS_NO_SETUP;
1811         ffs->flags = 0;
1812
1813         ffs->ms_os_descs_ext_prop_count = 0;
1814         ffs->ms_os_descs_ext_prop_name_len = 0;
1815         ffs->ms_os_descs_ext_prop_data_len = 0;
1816 }
1817
1818
1819 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1820 {
1821         struct usb_gadget_strings **lang;
1822         int first_id;
1823
1824         ENTER();
1825
1826         if (WARN_ON(ffs->state != FFS_ACTIVE
1827                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1828                 return -EBADFD;
1829
1830         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1831         if (unlikely(first_id < 0))
1832                 return first_id;
1833
1834         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1835         if (unlikely(!ffs->ep0req))
1836                 return -ENOMEM;
1837         ffs->ep0req->complete = ffs_ep0_complete;
1838         ffs->ep0req->context = ffs;
1839
1840         lang = ffs->stringtabs;
1841         if (lang) {
1842                 for (; *lang; ++lang) {
1843                         struct usb_string *str = (*lang)->strings;
1844                         int id = first_id;
1845                         for (; str->s; ++id, ++str)
1846                                 str->id = id;
1847                 }
1848         }
1849
1850         ffs->gadget = cdev->gadget;
1851         ffs_data_get(ffs);
1852         return 0;
1853 }
1854
1855 static void functionfs_unbind(struct ffs_data *ffs)
1856 {
1857         ENTER();
1858
1859         if (!WARN_ON(!ffs->gadget)) {
1860                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1861                 ffs->ep0req = NULL;
1862                 ffs->gadget = NULL;
1863                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1864                 ffs_data_put(ffs);
1865         }
1866 }
1867
1868 static int ffs_epfiles_create(struct ffs_data *ffs)
1869 {
1870         struct ffs_epfile *epfile, *epfiles;
1871         unsigned i, count;
1872
1873         ENTER();
1874
1875         count = ffs->eps_count;
1876         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1877         if (!epfiles)
1878                 return -ENOMEM;
1879
1880         epfile = epfiles;
1881         for (i = 1; i <= count; ++i, ++epfile) {
1882                 epfile->ffs = ffs;
1883                 mutex_init(&epfile->mutex);
1884                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1885                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1886                 else
1887                         sprintf(epfile->name, "ep%u", i);
1888                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1889                                                  epfile,
1890                                                  &ffs_epfile_operations);
1891                 if (unlikely(!epfile->dentry)) {
1892                         ffs_epfiles_destroy(epfiles, i - 1);
1893                         return -ENOMEM;
1894                 }
1895         }
1896
1897         ffs->epfiles = epfiles;
1898         return 0;
1899 }
1900
1901 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1902 {
1903         struct ffs_epfile *epfile = epfiles;
1904
1905         ENTER();
1906
1907         for (; count; --count, ++epfile) {
1908                 BUG_ON(mutex_is_locked(&epfile->mutex));
1909                 if (epfile->dentry) {
1910                         d_delete(epfile->dentry);
1911                         dput(epfile->dentry);
1912                         epfile->dentry = NULL;
1913                 }
1914         }
1915
1916         kfree(epfiles);
1917 }
1918
1919 static void ffs_func_eps_disable(struct ffs_function *func)
1920 {
1921         struct ffs_ep *ep         = func->eps;
1922         struct ffs_epfile *epfile = func->ffs->epfiles;
1923         unsigned count            = func->ffs->eps_count;
1924         unsigned long flags;
1925
1926         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1927         while (count--) {
1928                 /* pending requests get nuked */
1929                 if (likely(ep->ep))
1930                         usb_ep_disable(ep->ep);
1931                 ++ep;
1932
1933                 if (epfile) {
1934                         epfile->ep = NULL;
1935                         __ffs_epfile_read_buffer_free(epfile);
1936                         ++epfile;
1937                 }
1938         }
1939         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1940 }
1941
1942 static int ffs_func_eps_enable(struct ffs_function *func)
1943 {
1944         struct ffs_data *ffs      = func->ffs;
1945         struct ffs_ep *ep         = func->eps;
1946         struct ffs_epfile *epfile = ffs->epfiles;
1947         unsigned count            = ffs->eps_count;
1948         unsigned long flags;
1949         int ret = 0;
1950
1951         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1952         while(count--) {
1953                 ep->ep->driver_data = ep;
1954
1955                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1956                 if (ret) {
1957                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1958                                         __func__, ep->ep->name, ret);
1959                         break;
1960                 }
1961
1962                 ret = usb_ep_enable(ep->ep);
1963                 if (likely(!ret)) {
1964                         epfile->ep = ep;
1965                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1966                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1967                 } else {
1968                         break;
1969                 }
1970
1971                 ++ep;
1972                 ++epfile;
1973         }
1974
1975         wake_up_interruptible(&ffs->wait);
1976         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1977
1978         return ret;
1979 }
1980
1981
1982 /* Parsing and building descriptors and strings *****************************/
1983
1984 /*
1985  * This validates if data pointed by data is a valid USB descriptor as
1986  * well as record how many interfaces, endpoints and strings are
1987  * required by given configuration.  Returns address after the
1988  * descriptor or NULL if data is invalid.
1989  */
1990
1991 enum ffs_entity_type {
1992         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1993 };
1994
1995 enum ffs_os_desc_type {
1996         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1997 };
1998
1999 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2000                                    u8 *valuep,
2001                                    struct usb_descriptor_header *desc,
2002                                    void *priv);
2003
2004 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2005                                     struct usb_os_desc_header *h, void *data,
2006                                     unsigned len, void *priv);
2007
2008 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2009                                            ffs_entity_callback entity,
2010                                            void *priv, int *current_class)
2011 {
2012         struct usb_descriptor_header *_ds = (void *)data;
2013         u8 length;
2014         int ret;
2015
2016         ENTER();
2017
2018         /* At least two bytes are required: length and type */
2019         if (len < 2) {
2020                 pr_vdebug("descriptor too short\n");
2021                 return -EINVAL;
2022         }
2023
2024         /* If we have at least as many bytes as the descriptor takes? */
2025         length = _ds->bLength;
2026         if (len < length) {
2027                 pr_vdebug("descriptor longer then available data\n");
2028                 return -EINVAL;
2029         }
2030
2031 #define __entity_check_INTERFACE(val)  1
2032 #define __entity_check_STRING(val)     (val)
2033 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2034 #define __entity(type, val) do {                                        \
2035                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2036                 if (unlikely(!__entity_check_ ##type(val))) {           \
2037                         pr_vdebug("invalid entity's value\n");          \
2038                         return -EINVAL;                                 \
2039                 }                                                       \
2040                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2041                 if (unlikely(ret < 0)) {                                \
2042                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2043                                  (val), ret);                           \
2044                         return ret;                                     \
2045                 }                                                       \
2046         } while (0)
2047
2048         /* Parse descriptor depending on type. */
2049         switch (_ds->bDescriptorType) {
2050         case USB_DT_DEVICE:
2051         case USB_DT_CONFIG:
2052         case USB_DT_STRING:
2053         case USB_DT_DEVICE_QUALIFIER:
2054                 /* function can't have any of those */
2055                 pr_vdebug("descriptor reserved for gadget: %d\n",
2056                       _ds->bDescriptorType);
2057                 return -EINVAL;
2058
2059         case USB_DT_INTERFACE: {
2060                 struct usb_interface_descriptor *ds = (void *)_ds;
2061                 pr_vdebug("interface descriptor\n");
2062                 if (length != sizeof *ds)
2063                         goto inv_length;
2064
2065                 __entity(INTERFACE, ds->bInterfaceNumber);
2066                 if (ds->iInterface)
2067                         __entity(STRING, ds->iInterface);
2068                 *current_class = ds->bInterfaceClass;
2069         }
2070                 break;
2071
2072         case USB_DT_ENDPOINT: {
2073                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2074                 pr_vdebug("endpoint descriptor\n");
2075                 if (length != USB_DT_ENDPOINT_SIZE &&
2076                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2077                         goto inv_length;
2078                 __entity(ENDPOINT, ds->bEndpointAddress);
2079         }
2080                 break;
2081
2082         case USB_TYPE_CLASS | 0x01:
2083                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2084                         pr_vdebug("hid descriptor\n");
2085                         if (length != sizeof(struct hid_descriptor))
2086                                 goto inv_length;
2087                         break;
2088                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2089                         pr_vdebug("ccid descriptor\n");
2090                         if (length != sizeof(struct ccid_descriptor))
2091                                 goto inv_length;
2092                         break;
2093                 } else {
2094                         pr_vdebug("unknown descriptor: %d for class %d\n",
2095                               _ds->bDescriptorType, *current_class);
2096                         return -EINVAL;
2097                 }
2098
2099         case USB_DT_OTG:
2100                 if (length != sizeof(struct usb_otg_descriptor))
2101                         goto inv_length;
2102                 break;
2103
2104         case USB_DT_INTERFACE_ASSOCIATION: {
2105                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2106                 pr_vdebug("interface association descriptor\n");
2107                 if (length != sizeof *ds)
2108                         goto inv_length;
2109                 if (ds->iFunction)
2110                         __entity(STRING, ds->iFunction);
2111         }
2112                 break;
2113
2114         case USB_DT_SS_ENDPOINT_COMP:
2115                 pr_vdebug("EP SS companion descriptor\n");
2116                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2117                         goto inv_length;
2118                 break;
2119
2120         case USB_DT_OTHER_SPEED_CONFIG:
2121         case USB_DT_INTERFACE_POWER:
2122         case USB_DT_DEBUG:
2123         case USB_DT_SECURITY:
2124         case USB_DT_CS_RADIO_CONTROL:
2125                 /* TODO */
2126                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2127                 return -EINVAL;
2128
2129         default:
2130                 /* We should never be here */
2131                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2132                 return -EINVAL;
2133
2134 inv_length:
2135                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2136                           _ds->bLength, _ds->bDescriptorType);
2137                 return -EINVAL;
2138         }
2139
2140 #undef __entity
2141 #undef __entity_check_DESCRIPTOR
2142 #undef __entity_check_INTERFACE
2143 #undef __entity_check_STRING
2144 #undef __entity_check_ENDPOINT
2145
2146         return length;
2147 }
2148
2149 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2150                                      ffs_entity_callback entity, void *priv)
2151 {
2152         const unsigned _len = len;
2153         unsigned long num = 0;
2154         int current_class = -1;
2155
2156         ENTER();
2157
2158         for (;;) {
2159                 int ret;
2160
2161                 if (num == count)
2162                         data = NULL;
2163
2164                 /* Record "descriptor" entity */
2165                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2166                 if (unlikely(ret < 0)) {
2167                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2168                                  num, ret);
2169                         return ret;
2170                 }
2171
2172                 if (!data)
2173                         return _len - len;
2174
2175                 ret = ffs_do_single_desc(data, len, entity, priv,
2176                         &current_class);
2177                 if (unlikely(ret < 0)) {
2178                         pr_debug("%s returns %d\n", __func__, ret);
2179                         return ret;
2180                 }
2181
2182                 len -= ret;
2183                 data += ret;
2184                 ++num;
2185         }
2186 }
2187
2188 static int __ffs_data_do_entity(enum ffs_entity_type type,
2189                                 u8 *valuep, struct usb_descriptor_header *desc,
2190                                 void *priv)
2191 {
2192         struct ffs_desc_helper *helper = priv;
2193         struct usb_endpoint_descriptor *d;
2194
2195         ENTER();
2196
2197         switch (type) {
2198         case FFS_DESCRIPTOR:
2199                 break;
2200
2201         case FFS_INTERFACE:
2202                 /*
2203                  * Interfaces are indexed from zero so if we
2204                  * encountered interface "n" then there are at least
2205                  * "n+1" interfaces.
2206                  */
2207                 if (*valuep >= helper->interfaces_count)
2208                         helper->interfaces_count = *valuep + 1;
2209                 break;
2210
2211         case FFS_STRING:
2212                 /*
2213                  * Strings are indexed from 1 (0 is reserved
2214                  * for languages list)
2215                  */
2216                 if (*valuep > helper->ffs->strings_count)
2217                         helper->ffs->strings_count = *valuep;
2218                 break;
2219
2220         case FFS_ENDPOINT:
2221                 d = (void *)desc;
2222                 helper->eps_count++;
2223                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2224                         return -EINVAL;
2225                 /* Check if descriptors for any speed were already parsed */
2226                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2227                         helper->ffs->eps_addrmap[helper->eps_count] =
2228                                 d->bEndpointAddress;
2229                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2230                                 d->bEndpointAddress)
2231                         return -EINVAL;
2232                 break;
2233         }
2234
2235         return 0;
2236 }
2237
2238 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2239                                    struct usb_os_desc_header *desc)
2240 {
2241         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2242         u16 w_index = le16_to_cpu(desc->wIndex);
2243
2244         if (bcd_version != 1) {
2245                 pr_vdebug("unsupported os descriptors version: %d",
2246                           bcd_version);
2247                 return -EINVAL;
2248         }
2249         switch (w_index) {
2250         case 0x4:
2251                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2252                 break;
2253         case 0x5:
2254                 *next_type = FFS_OS_DESC_EXT_PROP;
2255                 break;
2256         default:
2257                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2258                 return -EINVAL;
2259         }
2260
2261         return sizeof(*desc);
2262 }
2263
2264 /*
2265  * Process all extended compatibility/extended property descriptors
2266  * of a feature descriptor
2267  */
2268 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2269                                               enum ffs_os_desc_type type,
2270                                               u16 feature_count,
2271                                               ffs_os_desc_callback entity,
2272                                               void *priv,
2273                                               struct usb_os_desc_header *h)
2274 {
2275         int ret;
2276         const unsigned _len = len;
2277
2278         ENTER();
2279
2280         /* loop over all ext compat/ext prop descriptors */
2281         while (feature_count--) {
2282                 ret = entity(type, h, data, len, priv);
2283                 if (unlikely(ret < 0)) {
2284                         pr_debug("bad OS descriptor, type: %d\n", type);
2285                         return ret;
2286                 }
2287                 data += ret;
2288                 len -= ret;
2289         }
2290         return _len - len;
2291 }
2292
2293 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2294 static int __must_check ffs_do_os_descs(unsigned count,
2295                                         char *data, unsigned len,
2296                                         ffs_os_desc_callback entity, void *priv)
2297 {
2298         const unsigned _len = len;
2299         unsigned long num = 0;
2300
2301         ENTER();
2302
2303         for (num = 0; num < count; ++num) {
2304                 int ret;
2305                 enum ffs_os_desc_type type;
2306                 u16 feature_count;
2307                 struct usb_os_desc_header *desc = (void *)data;
2308
2309                 if (len < sizeof(*desc))
2310                         return -EINVAL;
2311
2312                 /*
2313                  * Record "descriptor" entity.
2314                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2315                  * Move the data pointer to the beginning of extended
2316                  * compatibilities proper or extended properties proper
2317                  * portions of the data
2318                  */
2319                 if (le32_to_cpu(desc->dwLength) > len)
2320                         return -EINVAL;
2321
2322                 ret = __ffs_do_os_desc_header(&type, desc);
2323                 if (unlikely(ret < 0)) {
2324                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2325                                  num, ret);
2326                         return ret;
2327                 }
2328                 /*
2329                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2330                  */
2331                 feature_count = le16_to_cpu(desc->wCount);
2332                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2333                     (feature_count > 255 || desc->Reserved))
2334                                 return -EINVAL;
2335                 len -= ret;
2336                 data += ret;
2337
2338                 /*
2339                  * Process all function/property descriptors
2340                  * of this Feature Descriptor
2341                  */
2342                 ret = ffs_do_single_os_desc(data, len, type,
2343                                             feature_count, entity, priv, desc);
2344                 if (unlikely(ret < 0)) {
2345                         pr_debug("%s returns %d\n", __func__, ret);
2346                         return ret;
2347                 }
2348
2349                 len -= ret;
2350                 data += ret;
2351         }
2352         return _len - len;
2353 }
2354
2355 /*
2356  * Validate contents of the buffer from userspace related to OS descriptors.
2357  */
2358 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2359                                  struct usb_os_desc_header *h, void *data,
2360                                  unsigned len, void *priv)
2361 {
2362         struct ffs_data *ffs = priv;
2363         u8 length;
2364
2365         ENTER();
2366
2367         switch (type) {
2368         case FFS_OS_DESC_EXT_COMPAT: {
2369                 struct usb_ext_compat_desc *d = data;
2370                 int i;
2371
2372                 if (len < sizeof(*d) ||
2373                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2374                         return -EINVAL;
2375                 if (d->Reserved1 != 1) {
2376                         /*
2377                          * According to the spec, Reserved1 must be set to 1
2378                          * but older kernels incorrectly rejected non-zero
2379                          * values.  We fix it here to avoid returning EINVAL
2380                          * in response to values we used to accept.
2381                          */
2382                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2383                         d->Reserved1 = 1;
2384                 }
2385                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2386                         if (d->Reserved2[i])
2387                                 return -EINVAL;
2388
2389                 length = sizeof(struct usb_ext_compat_desc);
2390         }
2391                 break;
2392         case FFS_OS_DESC_EXT_PROP: {
2393                 struct usb_ext_prop_desc *d = data;
2394                 u32 type, pdl;
2395                 u16 pnl;
2396
2397                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2398                         return -EINVAL;
2399                 length = le32_to_cpu(d->dwSize);
2400                 if (len < length)
2401                         return -EINVAL;
2402                 type = le32_to_cpu(d->dwPropertyDataType);
2403                 if (type < USB_EXT_PROP_UNICODE ||
2404                     type > USB_EXT_PROP_UNICODE_MULTI) {
2405                         pr_vdebug("unsupported os descriptor property type: %d",
2406                                   type);
2407                         return -EINVAL;
2408                 }
2409                 pnl = le16_to_cpu(d->wPropertyNameLength);
2410                 if (length < 14 + pnl) {
2411                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2412                                   length, pnl, type);
2413                         return -EINVAL;
2414                 }
2415                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2416                 if (length != 14 + pnl + pdl) {
2417                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2418                                   length, pnl, pdl, type);
2419                         return -EINVAL;
2420                 }
2421                 ++ffs->ms_os_descs_ext_prop_count;
2422                 /* property name reported to the host as "WCHAR"s */
2423                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2424                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2425         }
2426                 break;
2427         default:
2428                 pr_vdebug("unknown descriptor: %d\n", type);
2429                 return -EINVAL;
2430         }
2431         return length;
2432 }
2433
2434 static int __ffs_data_got_descs(struct ffs_data *ffs,
2435                                 char *const _data, size_t len)
2436 {
2437         char *data = _data, *raw_descs;
2438         unsigned os_descs_count = 0, counts[3], flags;
2439         int ret = -EINVAL, i;
2440         struct ffs_desc_helper helper;
2441
2442         ENTER();
2443
2444         if (get_unaligned_le32(data + 4) != len)
2445                 goto error;
2446
2447         switch (get_unaligned_le32(data)) {
2448         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2449                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2450                 data += 8;
2451                 len  -= 8;
2452                 break;
2453         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2454                 flags = get_unaligned_le32(data + 8);
2455                 ffs->user_flags = flags;
2456                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2457                               FUNCTIONFS_HAS_HS_DESC |
2458                               FUNCTIONFS_HAS_SS_DESC |
2459                               FUNCTIONFS_HAS_MS_OS_DESC |
2460                               FUNCTIONFS_VIRTUAL_ADDR |
2461                               FUNCTIONFS_EVENTFD |
2462                               FUNCTIONFS_ALL_CTRL_RECIP |
2463                               FUNCTIONFS_CONFIG0_SETUP)) {
2464                         ret = -ENOSYS;
2465                         goto error;
2466                 }
2467                 data += 12;
2468                 len  -= 12;
2469                 break;
2470         default:
2471                 goto error;
2472         }
2473
2474         if (flags & FUNCTIONFS_EVENTFD) {
2475                 if (len < 4)
2476                         goto error;
2477                 ffs->ffs_eventfd =
2478                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2479                 if (IS_ERR(ffs->ffs_eventfd)) {
2480                         ret = PTR_ERR(ffs->ffs_eventfd);
2481                         ffs->ffs_eventfd = NULL;
2482                         goto error;
2483                 }
2484                 data += 4;
2485                 len  -= 4;
2486         }
2487
2488         /* Read fs_count, hs_count and ss_count (if present) */
2489         for (i = 0; i < 3; ++i) {
2490                 if (!(flags & (1 << i))) {
2491                         counts[i] = 0;
2492                 } else if (len < 4) {
2493                         goto error;
2494                 } else {
2495                         counts[i] = get_unaligned_le32(data);
2496                         data += 4;
2497                         len  -= 4;
2498                 }
2499         }
2500         if (flags & (1 << i)) {
2501                 if (len < 4) {
2502                         goto error;
2503                 }
2504                 os_descs_count = get_unaligned_le32(data);
2505                 data += 4;
2506                 len -= 4;
2507         }
2508
2509         /* Read descriptors */
2510         raw_descs = data;
2511         helper.ffs = ffs;
2512         for (i = 0; i < 3; ++i) {
2513                 if (!counts[i])
2514                         continue;
2515                 helper.interfaces_count = 0;
2516                 helper.eps_count = 0;
2517                 ret = ffs_do_descs(counts[i], data, len,
2518                                    __ffs_data_do_entity, &helper);
2519                 if (ret < 0)
2520                         goto error;
2521                 if (!ffs->eps_count && !ffs->interfaces_count) {
2522                         ffs->eps_count = helper.eps_count;
2523                         ffs->interfaces_count = helper.interfaces_count;
2524                 } else {
2525                         if (ffs->eps_count != helper.eps_count) {
2526                                 ret = -EINVAL;
2527                                 goto error;
2528                         }
2529                         if (ffs->interfaces_count != helper.interfaces_count) {
2530                                 ret = -EINVAL;
2531                                 goto error;
2532                         }
2533                 }
2534                 data += ret;
2535                 len  -= ret;
2536         }
2537         if (os_descs_count) {
2538                 ret = ffs_do_os_descs(os_descs_count, data, len,
2539                                       __ffs_data_do_os_desc, ffs);
2540                 if (ret < 0)
2541                         goto error;
2542                 data += ret;
2543                 len -= ret;
2544         }
2545
2546         if (raw_descs == data || len) {
2547                 ret = -EINVAL;
2548                 goto error;
2549         }
2550
2551         ffs->raw_descs_data     = _data;
2552         ffs->raw_descs          = raw_descs;
2553         ffs->raw_descs_length   = data - raw_descs;
2554         ffs->fs_descs_count     = counts[0];
2555         ffs->hs_descs_count     = counts[1];
2556         ffs->ss_descs_count     = counts[2];
2557         ffs->ms_os_descs_count  = os_descs_count;
2558
2559         return 0;
2560
2561 error:
2562         kfree(_data);
2563         return ret;
2564 }
2565
2566 static int __ffs_data_got_strings(struct ffs_data *ffs,
2567                                   char *const _data, size_t len)
2568 {
2569         u32 str_count, needed_count, lang_count;
2570         struct usb_gadget_strings **stringtabs, *t;
2571         const char *data = _data;
2572         struct usb_string *s;
2573
2574         ENTER();
2575
2576         if (unlikely(len < 16 ||
2577                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2578                      get_unaligned_le32(data + 4) != len))
2579                 goto error;
2580         str_count  = get_unaligned_le32(data + 8);
2581         lang_count = get_unaligned_le32(data + 12);
2582
2583         /* if one is zero the other must be zero */
2584         if (unlikely(!str_count != !lang_count))
2585                 goto error;
2586
2587         /* Do we have at least as many strings as descriptors need? */
2588         needed_count = ffs->strings_count;
2589         if (unlikely(str_count < needed_count))
2590                 goto error;
2591
2592         /*
2593          * If we don't need any strings just return and free all
2594          * memory.
2595          */
2596         if (!needed_count) {
2597                 kfree(_data);
2598                 return 0;
2599         }
2600
2601         /* Allocate everything in one chunk so there's less maintenance. */
2602         {
2603                 unsigned i = 0;
2604                 vla_group(d);
2605                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2606                         lang_count + 1);
2607                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2608                 vla_item(d, struct usb_string, strings,
2609                         lang_count*(needed_count+1));
2610
2611                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2612
2613                 if (unlikely(!vlabuf)) {
2614                         kfree(_data);
2615                         return -ENOMEM;
2616                 }
2617
2618                 /* Initialize the VLA pointers */
2619                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2620                 t = vla_ptr(vlabuf, d, stringtab);
2621                 i = lang_count;
2622                 do {
2623                         *stringtabs++ = t++;
2624                 } while (--i);
2625                 *stringtabs = NULL;
2626
2627                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2628                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2629                 t = vla_ptr(vlabuf, d, stringtab);
2630                 s = vla_ptr(vlabuf, d, strings);
2631         }
2632
2633         /* For each language */
2634         data += 16;
2635         len -= 16;
2636
2637         do { /* lang_count > 0 so we can use do-while */
2638                 unsigned needed = needed_count;
2639
2640                 if (unlikely(len < 3))
2641                         goto error_free;
2642                 t->language = get_unaligned_le16(data);
2643                 t->strings  = s;
2644                 ++t;
2645
2646                 data += 2;
2647                 len -= 2;
2648
2649                 /* For each string */
2650                 do { /* str_count > 0 so we can use do-while */
2651                         size_t length = strnlen(data, len);
2652
2653                         if (unlikely(length == len))
2654                                 goto error_free;
2655
2656                         /*
2657                          * User may provide more strings then we need,
2658                          * if that's the case we simply ignore the
2659                          * rest
2660                          */
2661                         if (likely(needed)) {
2662                                 /*
2663                                  * s->id will be set while adding
2664                                  * function to configuration so for
2665                                  * now just leave garbage here.
2666                                  */
2667                                 s->s = data;
2668                                 --needed;
2669                                 ++s;
2670                         }
2671
2672                         data += length + 1;
2673                         len -= length + 1;
2674                 } while (--str_count);
2675
2676                 s->id = 0;   /* terminator */
2677                 s->s = NULL;
2678                 ++s;
2679
2680         } while (--lang_count);
2681
2682         /* Some garbage left? */
2683         if (unlikely(len))
2684                 goto error_free;
2685
2686         /* Done! */
2687         ffs->stringtabs = stringtabs;
2688         ffs->raw_strings = _data;
2689
2690         return 0;
2691
2692 error_free:
2693         kfree(stringtabs);
2694 error:
2695         kfree(_data);
2696         return -EINVAL;
2697 }
2698
2699
2700 /* Events handling and management *******************************************/
2701
2702 static void __ffs_event_add(struct ffs_data *ffs,
2703                             enum usb_functionfs_event_type type)
2704 {
2705         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2706         int neg = 0;
2707
2708         /*
2709          * Abort any unhandled setup
2710          *
2711          * We do not need to worry about some cmpxchg() changing value
2712          * of ffs->setup_state without holding the lock because when
2713          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2714          * the source does nothing.
2715          */
2716         if (ffs->setup_state == FFS_SETUP_PENDING)
2717                 ffs->setup_state = FFS_SETUP_CANCELLED;
2718
2719         /*
2720          * Logic of this function guarantees that there are at most four pending
2721          * evens on ffs->ev.types queue.  This is important because the queue
2722          * has space for four elements only and __ffs_ep0_read_events function
2723          * depends on that limit as well.  If more event types are added, those
2724          * limits have to be revisited or guaranteed to still hold.
2725          */
2726         switch (type) {
2727         case FUNCTIONFS_RESUME:
2728                 rem_type2 = FUNCTIONFS_SUSPEND;
2729                 fallthrough;
2730         case FUNCTIONFS_SUSPEND:
2731         case FUNCTIONFS_SETUP:
2732                 rem_type1 = type;
2733                 /* Discard all similar events */
2734                 break;
2735
2736         case FUNCTIONFS_BIND:
2737         case FUNCTIONFS_UNBIND:
2738         case FUNCTIONFS_DISABLE:
2739         case FUNCTIONFS_ENABLE:
2740                 /* Discard everything other then power management. */
2741                 rem_type1 = FUNCTIONFS_SUSPEND;
2742                 rem_type2 = FUNCTIONFS_RESUME;
2743                 neg = 1;
2744                 break;
2745
2746         default:
2747                 WARN(1, "%d: unknown event, this should not happen\n", type);
2748                 return;
2749         }
2750
2751         {
2752                 u8 *ev  = ffs->ev.types, *out = ev;
2753                 unsigned n = ffs->ev.count;
2754                 for (; n; --n, ++ev)
2755                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2756                                 *out++ = *ev;
2757                         else
2758                                 pr_vdebug("purging event %d\n", *ev);
2759                 ffs->ev.count = out - ffs->ev.types;
2760         }
2761
2762         pr_vdebug("adding event %d\n", type);
2763         ffs->ev.types[ffs->ev.count++] = type;
2764         wake_up_locked(&ffs->ev.waitq);
2765         if (ffs->ffs_eventfd)
2766                 eventfd_signal(ffs->ffs_eventfd, 1);
2767 }
2768
2769 static void ffs_event_add(struct ffs_data *ffs,
2770                           enum usb_functionfs_event_type type)
2771 {
2772         unsigned long flags;
2773         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2774         __ffs_event_add(ffs, type);
2775         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2776 }
2777
2778 /* Bind/unbind USB function hooks *******************************************/
2779
2780 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2781 {
2782         int i;
2783
2784         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2785                 if (ffs->eps_addrmap[i] == endpoint_address)
2786                         return i;
2787         return -ENOENT;
2788 }
2789
2790 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2791                                     struct usb_descriptor_header *desc,
2792                                     void *priv)
2793 {
2794         struct usb_endpoint_descriptor *ds = (void *)desc;
2795         struct ffs_function *func = priv;
2796         struct ffs_ep *ffs_ep;
2797         unsigned ep_desc_id;
2798         int idx;
2799         static const char *speed_names[] = { "full", "high", "super" };
2800
2801         if (type != FFS_DESCRIPTOR)
2802                 return 0;
2803
2804         /*
2805          * If ss_descriptors is not NULL, we are reading super speed
2806          * descriptors; if hs_descriptors is not NULL, we are reading high
2807          * speed descriptors; otherwise, we are reading full speed
2808          * descriptors.
2809          */
2810         if (func->function.ss_descriptors) {
2811                 ep_desc_id = 2;
2812                 func->function.ss_descriptors[(long)valuep] = desc;
2813         } else if (func->function.hs_descriptors) {
2814                 ep_desc_id = 1;
2815                 func->function.hs_descriptors[(long)valuep] = desc;
2816         } else {
2817                 ep_desc_id = 0;
2818                 func->function.fs_descriptors[(long)valuep]    = desc;
2819         }
2820
2821         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2822                 return 0;
2823
2824         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2825         if (idx < 0)
2826                 return idx;
2827
2828         ffs_ep = func->eps + idx;
2829
2830         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2831                 pr_err("two %sspeed descriptors for EP %d\n",
2832                           speed_names[ep_desc_id],
2833                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2834                 return -EINVAL;
2835         }
2836         ffs_ep->descs[ep_desc_id] = ds;
2837
2838         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2839         if (ffs_ep->ep) {
2840                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2841                 if (!ds->wMaxPacketSize)
2842                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2843         } else {
2844                 struct usb_request *req;
2845                 struct usb_ep *ep;
2846                 u8 bEndpointAddress;
2847                 u16 wMaxPacketSize;
2848
2849                 /*
2850                  * We back up bEndpointAddress because autoconfig overwrites
2851                  * it with physical endpoint address.
2852                  */
2853                 bEndpointAddress = ds->bEndpointAddress;
2854                 /*
2855                  * We back up wMaxPacketSize because autoconfig treats
2856                  * endpoint descriptors as if they were full speed.
2857                  */
2858                 wMaxPacketSize = ds->wMaxPacketSize;
2859                 pr_vdebug("autoconfig\n");
2860                 ep = usb_ep_autoconfig(func->gadget, ds);
2861                 if (unlikely(!ep))
2862                         return -ENOTSUPP;
2863                 ep->driver_data = func->eps + idx;
2864
2865                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2866                 if (unlikely(!req))
2867                         return -ENOMEM;
2868
2869                 ffs_ep->ep  = ep;
2870                 ffs_ep->req = req;
2871                 func->eps_revmap[ds->bEndpointAddress &
2872                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2873                 /*
2874                  * If we use virtual address mapping, we restore
2875                  * original bEndpointAddress value.
2876                  */
2877                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2878                         ds->bEndpointAddress = bEndpointAddress;
2879                 /*
2880                  * Restore wMaxPacketSize which was potentially
2881                  * overwritten by autoconfig.
2882                  */
2883                 ds->wMaxPacketSize = wMaxPacketSize;
2884         }
2885         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2886
2887         return 0;
2888 }
2889
2890 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2891                                    struct usb_descriptor_header *desc,
2892                                    void *priv)
2893 {
2894         struct ffs_function *func = priv;
2895         unsigned idx;
2896         u8 newValue;
2897
2898         switch (type) {
2899         default:
2900         case FFS_DESCRIPTOR:
2901                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2902                 return 0;
2903
2904         case FFS_INTERFACE:
2905                 idx = *valuep;
2906                 if (func->interfaces_nums[idx] < 0) {
2907                         int id = usb_interface_id(func->conf, &func->function);
2908                         if (unlikely(id < 0))
2909                                 return id;
2910                         func->interfaces_nums[idx] = id;
2911                 }
2912                 newValue = func->interfaces_nums[idx];
2913                 break;
2914
2915         case FFS_STRING:
2916                 /* String' IDs are allocated when fsf_data is bound to cdev */
2917                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2918                 break;
2919
2920         case FFS_ENDPOINT:
2921                 /*
2922                  * USB_DT_ENDPOINT are handled in
2923                  * __ffs_func_bind_do_descs().
2924                  */
2925                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2926                         return 0;
2927
2928                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2929                 if (unlikely(!func->eps[idx].ep))
2930                         return -EINVAL;
2931
2932                 {
2933                         struct usb_endpoint_descriptor **descs;
2934                         descs = func->eps[idx].descs;
2935                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2936                 }
2937                 break;
2938         }
2939
2940         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2941         *valuep = newValue;
2942         return 0;
2943 }
2944
2945 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2946                                       struct usb_os_desc_header *h, void *data,
2947                                       unsigned len, void *priv)
2948 {
2949         struct ffs_function *func = priv;
2950         u8 length = 0;
2951
2952         switch (type) {
2953         case FFS_OS_DESC_EXT_COMPAT: {
2954                 struct usb_ext_compat_desc *desc = data;
2955                 struct usb_os_desc_table *t;
2956
2957                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2958                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2959                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2960                        ARRAY_SIZE(desc->CompatibleID) +
2961                        ARRAY_SIZE(desc->SubCompatibleID));
2962                 length = sizeof(*desc);
2963         }
2964                 break;
2965         case FFS_OS_DESC_EXT_PROP: {
2966                 struct usb_ext_prop_desc *desc = data;
2967                 struct usb_os_desc_table *t;
2968                 struct usb_os_desc_ext_prop *ext_prop;
2969                 char *ext_prop_name;
2970                 char *ext_prop_data;
2971
2972                 t = &func->function.os_desc_table[h->interface];
2973                 t->if_id = func->interfaces_nums[h->interface];
2974
2975                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2976                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2977
2978                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2979                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2980                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2981                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2982                 length = ext_prop->name_len + ext_prop->data_len + 14;
2983
2984                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2985                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2986                         ext_prop->name_len;
2987
2988                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2989                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2990                         ext_prop->data_len;
2991                 memcpy(ext_prop_data,
2992                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2993                        ext_prop->data_len);
2994                 /* unicode data reported to the host as "WCHAR"s */
2995                 switch (ext_prop->type) {
2996                 case USB_EXT_PROP_UNICODE:
2997                 case USB_EXT_PROP_UNICODE_ENV:
2998                 case USB_EXT_PROP_UNICODE_LINK:
2999                 case USB_EXT_PROP_UNICODE_MULTI:
3000                         ext_prop->data_len *= 2;
3001                         break;
3002                 }
3003                 ext_prop->data = ext_prop_data;
3004
3005                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3006                        ext_prop->name_len);
3007                 /* property name reported to the host as "WCHAR"s */
3008                 ext_prop->name_len *= 2;
3009                 ext_prop->name = ext_prop_name;
3010
3011                 t->os_desc->ext_prop_len +=
3012                         ext_prop->name_len + ext_prop->data_len + 14;
3013                 ++t->os_desc->ext_prop_count;
3014                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3015         }
3016                 break;
3017         default:
3018                 pr_vdebug("unknown descriptor: %d\n", type);
3019         }
3020
3021         return length;
3022 }
3023
3024 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3025                                                 struct usb_configuration *c)
3026 {
3027         struct ffs_function *func = ffs_func_from_usb(f);
3028         struct f_fs_opts *ffs_opts =
3029                 container_of(f->fi, struct f_fs_opts, func_inst);
3030         int ret;
3031
3032         ENTER();
3033
3034         /*
3035          * Legacy gadget triggers binding in functionfs_ready_callback,
3036          * which already uses locking; taking the same lock here would
3037          * cause a deadlock.
3038          *
3039          * Configfs-enabled gadgets however do need ffs_dev_lock.
3040          */
3041         if (!ffs_opts->no_configfs)
3042                 ffs_dev_lock();
3043         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3044         func->ffs = ffs_opts->dev->ffs_data;
3045         if (!ffs_opts->no_configfs)
3046                 ffs_dev_unlock();
3047         if (ret)
3048                 return ERR_PTR(ret);
3049
3050         func->conf = c;
3051         func->gadget = c->cdev->gadget;
3052
3053         /*
3054          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3055          * configurations are bound in sequence with list_for_each_entry,
3056          * in each configuration its functions are bound in sequence
3057          * with list_for_each_entry, so we assume no race condition
3058          * with regard to ffs_opts->bound access
3059          */
3060         if (!ffs_opts->refcnt) {
3061                 ret = functionfs_bind(func->ffs, c->cdev);
3062                 if (ret)
3063                         return ERR_PTR(ret);
3064         }
3065         ffs_opts->refcnt++;
3066         func->function.strings = func->ffs->stringtabs;
3067
3068         return ffs_opts;
3069 }
3070
3071 static int _ffs_func_bind(struct usb_configuration *c,
3072                           struct usb_function *f)
3073 {
3074         struct ffs_function *func = ffs_func_from_usb(f);
3075         struct ffs_data *ffs = func->ffs;
3076
3077         const int full = !!func->ffs->fs_descs_count;
3078         const int high = !!func->ffs->hs_descs_count;
3079         const int super = !!func->ffs->ss_descs_count;
3080
3081         int fs_len, hs_len, ss_len, ret, i;
3082         struct ffs_ep *eps_ptr;
3083
3084         /* Make it a single chunk, less management later on */
3085         vla_group(d);
3086         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3087         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3088                 full ? ffs->fs_descs_count + 1 : 0);
3089         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3090                 high ? ffs->hs_descs_count + 1 : 0);
3091         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3092                 super ? ffs->ss_descs_count + 1 : 0);
3093         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3094         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3095                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3096         vla_item_with_sz(d, char[16], ext_compat,
3097                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3098         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3099                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3100         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3101                          ffs->ms_os_descs_ext_prop_count);
3102         vla_item_with_sz(d, char, ext_prop_name,
3103                          ffs->ms_os_descs_ext_prop_name_len);
3104         vla_item_with_sz(d, char, ext_prop_data,
3105                          ffs->ms_os_descs_ext_prop_data_len);
3106         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3107         char *vlabuf;
3108
3109         ENTER();
3110
3111         /* Has descriptors only for speeds gadget does not support */
3112         if (unlikely(!(full | high | super)))
3113                 return -ENOTSUPP;
3114
3115         /* Allocate a single chunk, less management later on */
3116         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3117         if (unlikely(!vlabuf))
3118                 return -ENOMEM;
3119
3120         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3121         ffs->ms_os_descs_ext_prop_name_avail =
3122                 vla_ptr(vlabuf, d, ext_prop_name);
3123         ffs->ms_os_descs_ext_prop_data_avail =
3124                 vla_ptr(vlabuf, d, ext_prop_data);
3125
3126         /* Copy descriptors  */
3127         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3128                ffs->raw_descs_length);
3129
3130         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3131         eps_ptr = vla_ptr(vlabuf, d, eps);
3132         for (i = 0; i < ffs->eps_count; i++)
3133                 eps_ptr[i].num = -1;
3134
3135         /* Save pointers
3136          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3137         */
3138         func->eps             = vla_ptr(vlabuf, d, eps);
3139         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3140
3141         /*
3142          * Go through all the endpoint descriptors and allocate
3143          * endpoints first, so that later we can rewrite the endpoint
3144          * numbers without worrying that it may be described later on.
3145          */
3146         if (likely(full)) {
3147                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3148                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3149                                       vla_ptr(vlabuf, d, raw_descs),
3150                                       d_raw_descs__sz,
3151                                       __ffs_func_bind_do_descs, func);
3152                 if (unlikely(fs_len < 0)) {
3153                         ret = fs_len;
3154                         goto error;
3155                 }
3156         } else {
3157                 fs_len = 0;
3158         }
3159
3160         if (likely(high)) {
3161                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3162                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3163                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3164                                       d_raw_descs__sz - fs_len,
3165                                       __ffs_func_bind_do_descs, func);
3166                 if (unlikely(hs_len < 0)) {
3167                         ret = hs_len;
3168                         goto error;
3169                 }
3170         } else {
3171                 hs_len = 0;
3172         }
3173
3174         if (likely(super)) {
3175                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3176                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3177                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3178                                 d_raw_descs__sz - fs_len - hs_len,
3179                                 __ffs_func_bind_do_descs, func);
3180                 if (unlikely(ss_len < 0)) {
3181                         ret = ss_len;
3182                         goto error;
3183                 }
3184         } else {
3185                 ss_len = 0;
3186         }
3187
3188         /*
3189          * Now handle interface numbers allocation and interface and
3190          * endpoint numbers rewriting.  We can do that in one go
3191          * now.
3192          */
3193         ret = ffs_do_descs(ffs->fs_descs_count +
3194                            (high ? ffs->hs_descs_count : 0) +
3195                            (super ? ffs->ss_descs_count : 0),
3196                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3197                            __ffs_func_bind_do_nums, func);
3198         if (unlikely(ret < 0))
3199                 goto error;
3200
3201         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3202         if (c->cdev->use_os_string) {
3203                 for (i = 0; i < ffs->interfaces_count; ++i) {
3204                         struct usb_os_desc *desc;
3205
3206                         desc = func->function.os_desc_table[i].os_desc =
3207                                 vla_ptr(vlabuf, d, os_desc) +
3208                                 i * sizeof(struct usb_os_desc);
3209                         desc->ext_compat_id =
3210                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3211                         INIT_LIST_HEAD(&desc->ext_prop);
3212                 }
3213                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3214                                       vla_ptr(vlabuf, d, raw_descs) +
3215                                       fs_len + hs_len + ss_len,
3216                                       d_raw_descs__sz - fs_len - hs_len -
3217                                       ss_len,
3218                                       __ffs_func_bind_do_os_desc, func);
3219                 if (unlikely(ret < 0))
3220                         goto error;
3221         }
3222         func->function.os_desc_n =
3223                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3224
3225         /* And we're done */
3226         ffs_event_add(ffs, FUNCTIONFS_BIND);
3227         return 0;
3228
3229 error:
3230         /* XXX Do we need to release all claimed endpoints here? */
3231         return ret;
3232 }
3233
3234 static int ffs_func_bind(struct usb_configuration *c,
3235                          struct usb_function *f)
3236 {
3237         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3238         struct ffs_function *func = ffs_func_from_usb(f);
3239         int ret;
3240
3241         if (IS_ERR(ffs_opts))
3242                 return PTR_ERR(ffs_opts);
3243
3244         ret = _ffs_func_bind(c, f);
3245         if (ret && !--ffs_opts->refcnt)
3246                 functionfs_unbind(func->ffs);
3247
3248         return ret;
3249 }
3250
3251
3252 /* Other USB function hooks *************************************************/
3253
3254 static void ffs_reset_work(struct work_struct *work)
3255 {
3256         struct ffs_data *ffs = container_of(work,
3257                 struct ffs_data, reset_work);
3258         ffs_data_reset(ffs);
3259 }
3260
3261 static int ffs_func_set_alt(struct usb_function *f,
3262                             unsigned interface, unsigned alt)
3263 {
3264         struct ffs_function *func = ffs_func_from_usb(f);
3265         struct ffs_data *ffs = func->ffs;
3266         int ret = 0, intf;
3267
3268         if (alt != (unsigned)-1) {
3269                 intf = ffs_func_revmap_intf(func, interface);
3270                 if (unlikely(intf < 0))
3271                         return intf;
3272         }
3273
3274         if (ffs->func)
3275                 ffs_func_eps_disable(ffs->func);
3276
3277         if (ffs->state == FFS_DEACTIVATED) {
3278                 ffs->state = FFS_CLOSING;
3279                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3280                 schedule_work(&ffs->reset_work);
3281                 return -ENODEV;
3282         }
3283
3284         if (ffs->state != FFS_ACTIVE)
3285                 return -ENODEV;
3286
3287         if (alt == (unsigned)-1) {
3288                 ffs->func = NULL;
3289                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3290                 return 0;
3291         }
3292
3293         ffs->func = func;
3294         ret = ffs_func_eps_enable(func);
3295         if (likely(ret >= 0))
3296                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3297         return ret;
3298 }
3299
3300 static void ffs_func_disable(struct usb_function *f)
3301 {
3302         ffs_func_set_alt(f, 0, (unsigned)-1);
3303 }
3304
3305 static int ffs_func_setup(struct usb_function *f,
3306                           const struct usb_ctrlrequest *creq)
3307 {
3308         struct ffs_function *func = ffs_func_from_usb(f);
3309         struct ffs_data *ffs = func->ffs;
3310         unsigned long flags;
3311         int ret;
3312
3313         ENTER();
3314
3315         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3316         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3317         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3318         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3319         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3320
3321         /*
3322          * Most requests directed to interface go through here
3323          * (notable exceptions are set/get interface) so we need to
3324          * handle them.  All other either handled by composite or
3325          * passed to usb_configuration->setup() (if one is set).  No
3326          * matter, we will handle requests directed to endpoint here
3327          * as well (as it's straightforward).  Other request recipient
3328          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3329          * is being used.
3330          */
3331         if (ffs->state != FFS_ACTIVE)
3332                 return -ENODEV;
3333
3334         switch (creq->bRequestType & USB_RECIP_MASK) {
3335         case USB_RECIP_INTERFACE:
3336                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3337                 if (unlikely(ret < 0))
3338                         return ret;
3339                 break;
3340
3341         case USB_RECIP_ENDPOINT:
3342                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3343                 if (unlikely(ret < 0))
3344                         return ret;
3345                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3346                         ret = func->ffs->eps_addrmap[ret];
3347                 break;
3348
3349         default:
3350                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3351                         ret = le16_to_cpu(creq->wIndex);
3352                 else
3353                         return -EOPNOTSUPP;
3354         }
3355
3356         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3357         ffs->ev.setup = *creq;
3358         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3359         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3360         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3361
3362         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3363 }
3364
3365 static bool ffs_func_req_match(struct usb_function *f,
3366                                const struct usb_ctrlrequest *creq,
3367                                bool config0)
3368 {
3369         struct ffs_function *func = ffs_func_from_usb(f);
3370
3371         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3372                 return false;
3373
3374         switch (creq->bRequestType & USB_RECIP_MASK) {
3375         case USB_RECIP_INTERFACE:
3376                 return (ffs_func_revmap_intf(func,
3377                                              le16_to_cpu(creq->wIndex)) >= 0);
3378         case USB_RECIP_ENDPOINT:
3379                 return (ffs_func_revmap_ep(func,
3380                                            le16_to_cpu(creq->wIndex)) >= 0);
3381         default:
3382                 return (bool) (func->ffs->user_flags &
3383                                FUNCTIONFS_ALL_CTRL_RECIP);
3384         }
3385 }
3386
3387 static void ffs_func_suspend(struct usb_function *f)
3388 {
3389         ENTER();
3390         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3391 }
3392
3393 static void ffs_func_resume(struct usb_function *f)
3394 {
3395         ENTER();
3396         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3397 }
3398
3399
3400 /* Endpoint and interface numbers reverse mapping ***************************/
3401
3402 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3403 {
3404         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3405         return num ? num : -EDOM;
3406 }
3407
3408 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3409 {
3410         short *nums = func->interfaces_nums;
3411         unsigned count = func->ffs->interfaces_count;
3412
3413         for (; count; --count, ++nums) {
3414                 if (*nums >= 0 && *nums == intf)
3415                         return nums - func->interfaces_nums;
3416         }
3417
3418         return -EDOM;
3419 }
3420
3421
3422 /* Devices management *******************************************************/
3423
3424 static LIST_HEAD(ffs_devices);
3425
3426 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3427 {
3428         struct ffs_dev *dev;
3429
3430         if (!name)
3431                 return NULL;
3432
3433         list_for_each_entry(dev, &ffs_devices, entry) {
3434                 if (strcmp(dev->name, name) == 0)
3435                         return dev;
3436         }
3437
3438         return NULL;
3439 }
3440
3441 /*
3442  * ffs_lock must be taken by the caller of this function
3443  */
3444 static struct ffs_dev *_ffs_get_single_dev(void)
3445 {
3446         struct ffs_dev *dev;
3447
3448         if (list_is_singular(&ffs_devices)) {
3449                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3450                 if (dev->single)
3451                         return dev;
3452         }
3453
3454         return NULL;
3455 }
3456
3457 /*
3458  * ffs_lock must be taken by the caller of this function
3459  */
3460 static struct ffs_dev *_ffs_find_dev(const char *name)
3461 {
3462         struct ffs_dev *dev;
3463
3464         dev = _ffs_get_single_dev();
3465         if (dev)
3466                 return dev;
3467
3468         return _ffs_do_find_dev(name);
3469 }
3470
3471 /* Configfs support *********************************************************/
3472
3473 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3474 {
3475         return container_of(to_config_group(item), struct f_fs_opts,
3476                             func_inst.group);
3477 }
3478
3479 static void ffs_attr_release(struct config_item *item)
3480 {
3481         struct f_fs_opts *opts = to_ffs_opts(item);
3482
3483         usb_put_function_instance(&opts->func_inst);
3484 }
3485
3486 static struct configfs_item_operations ffs_item_ops = {
3487         .release        = ffs_attr_release,
3488 };
3489
3490 static const struct config_item_type ffs_func_type = {
3491         .ct_item_ops    = &ffs_item_ops,
3492         .ct_owner       = THIS_MODULE,
3493 };
3494
3495
3496 /* Function registration interface ******************************************/
3497
3498 static void ffs_free_inst(struct usb_function_instance *f)
3499 {
3500         struct f_fs_opts *opts;
3501
3502         opts = to_f_fs_opts(f);
3503         ffs_dev_lock();
3504         _ffs_free_dev(opts->dev);
3505         ffs_dev_unlock();
3506         kfree(opts);
3507 }
3508
3509 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3510 {
3511         if (strlen(name) >= sizeof_field(struct ffs_dev, name))
3512                 return -ENAMETOOLONG;
3513         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3514 }
3515
3516 static struct usb_function_instance *ffs_alloc_inst(void)
3517 {
3518         struct f_fs_opts *opts;
3519         struct ffs_dev *dev;
3520
3521         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3522         if (!opts)
3523                 return ERR_PTR(-ENOMEM);
3524
3525         opts->func_inst.set_inst_name = ffs_set_inst_name;
3526         opts->func_inst.free_func_inst = ffs_free_inst;
3527         ffs_dev_lock();
3528         dev = _ffs_alloc_dev();
3529         ffs_dev_unlock();
3530         if (IS_ERR(dev)) {
3531                 kfree(opts);
3532                 return ERR_CAST(dev);
3533         }
3534         opts->dev = dev;
3535         dev->opts = opts;
3536
3537         config_group_init_type_name(&opts->func_inst.group, "",
3538                                     &ffs_func_type);
3539         return &opts->func_inst;
3540 }
3541
3542 static void ffs_free(struct usb_function *f)
3543 {
3544         kfree(ffs_func_from_usb(f));
3545 }
3546
3547 static void ffs_func_unbind(struct usb_configuration *c,
3548                             struct usb_function *f)
3549 {
3550         struct ffs_function *func = ffs_func_from_usb(f);
3551         struct ffs_data *ffs = func->ffs;
3552         struct f_fs_opts *opts =
3553                 container_of(f->fi, struct f_fs_opts, func_inst);
3554         struct ffs_ep *ep = func->eps;
3555         unsigned count = ffs->eps_count;
3556         unsigned long flags;
3557
3558         ENTER();
3559         if (ffs->func == func) {
3560                 ffs_func_eps_disable(func);
3561                 ffs->func = NULL;
3562         }
3563
3564         if (!--opts->refcnt)
3565                 functionfs_unbind(ffs);
3566
3567         /* cleanup after autoconfig */
3568         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3569         while (count--) {
3570                 if (ep->ep && ep->req)
3571                         usb_ep_free_request(ep->ep, ep->req);
3572                 ep->req = NULL;
3573                 ++ep;
3574         }
3575         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3576         kfree(func->eps);
3577         func->eps = NULL;
3578         /*
3579          * eps, descriptors and interfaces_nums are allocated in the
3580          * same chunk so only one free is required.
3581          */
3582         func->function.fs_descriptors = NULL;
3583         func->function.hs_descriptors = NULL;
3584         func->function.ss_descriptors = NULL;
3585         func->interfaces_nums = NULL;
3586
3587         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3588 }
3589
3590 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3591 {
3592         struct ffs_function *func;
3593
3594         ENTER();
3595
3596         func = kzalloc(sizeof(*func), GFP_KERNEL);
3597         if (unlikely(!func))
3598                 return ERR_PTR(-ENOMEM);
3599
3600         func->function.name    = "Function FS Gadget";
3601
3602         func->function.bind    = ffs_func_bind;
3603         func->function.unbind  = ffs_func_unbind;
3604         func->function.set_alt = ffs_func_set_alt;
3605         func->function.disable = ffs_func_disable;
3606         func->function.setup   = ffs_func_setup;
3607         func->function.req_match = ffs_func_req_match;
3608         func->function.suspend = ffs_func_suspend;
3609         func->function.resume  = ffs_func_resume;
3610         func->function.free_func = ffs_free;
3611
3612         return &func->function;
3613 }
3614
3615 /*
3616  * ffs_lock must be taken by the caller of this function
3617  */
3618 static struct ffs_dev *_ffs_alloc_dev(void)
3619 {
3620         struct ffs_dev *dev;
3621         int ret;
3622
3623         if (_ffs_get_single_dev())
3624                         return ERR_PTR(-EBUSY);
3625
3626         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3627         if (!dev)
3628                 return ERR_PTR(-ENOMEM);
3629
3630         if (list_empty(&ffs_devices)) {
3631                 ret = functionfs_init();
3632                 if (ret) {
3633                         kfree(dev);
3634                         return ERR_PTR(ret);
3635                 }
3636         }
3637
3638         list_add(&dev->entry, &ffs_devices);
3639
3640         return dev;
3641 }
3642
3643 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3644 {
3645         struct ffs_dev *existing;
3646         int ret = 0;
3647
3648         ffs_dev_lock();
3649
3650         existing = _ffs_do_find_dev(name);
3651         if (!existing)
3652                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3653         else if (existing != dev)
3654                 ret = -EBUSY;
3655
3656         ffs_dev_unlock();
3657
3658         return ret;
3659 }
3660 EXPORT_SYMBOL_GPL(ffs_name_dev);
3661
3662 int ffs_single_dev(struct ffs_dev *dev)
3663 {
3664         int ret;
3665
3666         ret = 0;
3667         ffs_dev_lock();
3668
3669         if (!list_is_singular(&ffs_devices))
3670                 ret = -EBUSY;
3671         else
3672                 dev->single = true;
3673
3674         ffs_dev_unlock();
3675         return ret;
3676 }
3677 EXPORT_SYMBOL_GPL(ffs_single_dev);
3678
3679 /*
3680  * ffs_lock must be taken by the caller of this function
3681  */
3682 static void _ffs_free_dev(struct ffs_dev *dev)
3683 {
3684         list_del(&dev->entry);
3685
3686         /* Clear the private_data pointer to stop incorrect dev access */
3687         if (dev->ffs_data)
3688                 dev->ffs_data->private_data = NULL;
3689
3690         kfree(dev);
3691         if (list_empty(&ffs_devices))
3692                 functionfs_cleanup();
3693 }
3694
3695 static void *ffs_acquire_dev(const char *dev_name)
3696 {
3697         struct ffs_dev *ffs_dev;
3698
3699         ENTER();
3700         ffs_dev_lock();
3701
3702         ffs_dev = _ffs_find_dev(dev_name);
3703         if (!ffs_dev)
3704                 ffs_dev = ERR_PTR(-ENOENT);
3705         else if (ffs_dev->mounted)
3706                 ffs_dev = ERR_PTR(-EBUSY);
3707         else if (ffs_dev->ffs_acquire_dev_callback &&
3708             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3709                 ffs_dev = ERR_PTR(-ENOENT);
3710         else
3711                 ffs_dev->mounted = true;
3712
3713         ffs_dev_unlock();
3714         return ffs_dev;
3715 }
3716
3717 static void ffs_release_dev(struct ffs_data *ffs_data)
3718 {
3719         struct ffs_dev *ffs_dev;
3720
3721         ENTER();
3722         ffs_dev_lock();
3723
3724         ffs_dev = ffs_data->private_data;
3725         if (ffs_dev) {
3726                 ffs_dev->mounted = false;
3727
3728                 if (ffs_dev->ffs_release_dev_callback)
3729                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3730         }
3731
3732         ffs_dev_unlock();
3733 }
3734
3735 static int ffs_ready(struct ffs_data *ffs)
3736 {
3737         struct ffs_dev *ffs_obj;
3738         int ret = 0;
3739
3740         ENTER();
3741         ffs_dev_lock();
3742
3743         ffs_obj = ffs->private_data;
3744         if (!ffs_obj) {
3745                 ret = -EINVAL;
3746                 goto done;
3747         }
3748         if (WARN_ON(ffs_obj->desc_ready)) {
3749                 ret = -EBUSY;
3750                 goto done;
3751         }
3752
3753         ffs_obj->desc_ready = true;
3754         ffs_obj->ffs_data = ffs;
3755
3756         if (ffs_obj->ffs_ready_callback) {
3757                 ret = ffs_obj->ffs_ready_callback(ffs);
3758                 if (ret)
3759                         goto done;
3760         }
3761
3762         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3763 done:
3764         ffs_dev_unlock();
3765         return ret;
3766 }
3767
3768 static void ffs_closed(struct ffs_data *ffs)
3769 {
3770         struct ffs_dev *ffs_obj;
3771         struct f_fs_opts *opts;
3772         struct config_item *ci;
3773
3774         ENTER();
3775         ffs_dev_lock();
3776
3777         ffs_obj = ffs->private_data;
3778         if (!ffs_obj)
3779                 goto done;
3780
3781         ffs_obj->desc_ready = false;
3782         ffs_obj->ffs_data = NULL;
3783
3784         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3785             ffs_obj->ffs_closed_callback)
3786                 ffs_obj->ffs_closed_callback(ffs);
3787
3788         if (ffs_obj->opts)
3789                 opts = ffs_obj->opts;
3790         else
3791                 goto done;
3792
3793         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3794             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3795                 goto done;
3796
3797         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3798         ffs_dev_unlock();
3799
3800         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3801                 unregister_gadget_item(ci);
3802         return;
3803 done:
3804         ffs_dev_unlock();
3805 }
3806
3807 /* Misc helper functions ****************************************************/
3808
3809 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3810 {
3811         return nonblock
3812                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3813                 : mutex_lock_interruptible(mutex);
3814 }
3815
3816 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3817 {
3818         char *data;
3819
3820         if (unlikely(!len))
3821                 return NULL;
3822
3823         data = kmalloc(len, GFP_KERNEL);
3824         if (unlikely(!data))
3825                 return ERR_PTR(-ENOMEM);
3826
3827         if (unlikely(copy_from_user(data, buf, len))) {
3828                 kfree(data);
3829                 return ERR_PTR(-EFAULT);
3830         }
3831
3832         pr_vdebug("Buffer from user space:\n");
3833         ffs_dump_mem("", data, len);
3834
3835         return data;
3836 }
3837
3838 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3839 MODULE_LICENSE("GPL");
3840 MODULE_AUTHOR("Michal Nazarewicz");