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                 break;
 682
 683         case FFS_CLOSING:
 684                 break;
 685         case FFS_DEACTIVATED:
 686                 break;
 687         }
 688
 689         mutex_unlock(&ffs->mutex);
 690
 691         return mask;
 692 }
 693
 694 static const struct file_operations ffs_ep0_operations = {
 695         .llseek =       no_llseek,
 696
 697         .open =         ffs_ep0_open,
 698         .write =        ffs_ep0_write,
 699         .read =         ffs_ep0_read,
 700         .release =      ffs_ep0_release,
 701         .unlocked_ioctl =       ffs_ep0_ioctl,
 702         .poll =         ffs_ep0_poll,
 703 };
 704
 705
 706 /* "Normal" endpoints operations ********************************************/
 707
 708 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 709 {
 710         ENTER();
 711         if (likely(req->context)) {
 712                 struct ffs_ep *ep = _ep->driver_data;
 713                 ep->status = req->status ? req->status : req->actual;
 714                 complete(req->context);
 715         }
 716 }
 717
 718 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 719 {
 720         ssize_t ret = copy_to_iter(data, data_len, iter);
 721         if (likely(ret == data_len))
 722                 return ret;
 723
 724         if (unlikely(iov_iter_count(iter)))
 725                 return -EFAULT;
 726
 727         /*
 728          * Dear user space developer!
 729          *
 730          * TL;DR: To stop getting below error message in your kernel log, change
 731          * user space code using functionfs to align read buffers to a max
 732          * packet size.
 733          *
 734          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 735          * packet size.  When unaligned buffer is passed to functionfs, it
 736          * internally uses a larger, aligned buffer so that such UDCs are happy.
 737          *
 738          * Unfortunately, this means that host may send more data than was
 739          * requested in read(2) system call.  f_fs doesn’t know what to do with
 740          * that excess data so it simply drops it.
 741          *
 742          * Was the buffer aligned in the first place, no such problem would
 743          * happen.
 744          *
 745          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 746          * by splitting a request into multiple parts.  This splitting may still
 747          * be a problem though so it’s likely best to align the buffer
 748          * regardless of it being AIO or not..
 749          *
 750          * This only affects OUT endpoints, i.e. reading data with a read(2),
 751          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 752          * affected.
 753          */
 754         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 755                "Align read buffer size to max packet size to avoid the problem.\n",
 756                data_len, ret);
 757
 758         return ret;
 759 }
 760
 761 /*
 762  * allocate a virtually contiguous buffer and create a scatterlist describing it
 763  * @sg_table    - pointer to a place to be filled with sg_table contents
 764  * @size        - required buffer size
 765  */
 766 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 767 {
 768         struct page **pages;
 769         void *vaddr, *ptr;
 770         unsigned int n_pages;
 771         int i;
 772
 773         vaddr = vmalloc(sz);
 774         if (!vaddr)
 775                 return NULL;
 776
 777         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 778         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 779         if (!pages) {
 780                 vfree(vaddr);
 781
 782                 return NULL;
 783         }
 784         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 785                 pages[i] = vmalloc_to_page(ptr);
 786
 787         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 788                 kvfree(pages);
 789                 vfree(vaddr);
 790
 791                 return NULL;
 792         }
 793         kvfree(pages);
 794
 795         return vaddr;
 796 }
 797
 798 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 799         size_t data_len)
 800 {
 801         if (io_data->use_sg)
 802                 return ffs_build_sg_list(&io_data->sgt, data_len);
 803
 804         return kmalloc(data_len, GFP_KERNEL);
 805 }
 806
 807 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 808 {
 809         if (!io_data->buf)
 810                 return;
 811
 812         if (io_data->use_sg) {
 813                 sg_free_table(&io_data->sgt);
 814                 vfree(io_data->buf);
 815         } else {
 816                 kfree(io_data->buf);
 817         }
 818 }
 819
 820 static void ffs_user_copy_worker(struct work_struct *work)
 821 {
 822         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 823                                                    work);
 824         int ret = io_data->req->status ? io_data->req->status :
 825                                          io_data->req->actual;
 826         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 827
 828         if (io_data->read && ret > 0) {
 829                 kthread_use_mm(io_data->mm);
 830                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 831                 kthread_unuse_mm(io_data->mm);
 832         }
 833
 834         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 835
 836         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 837                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 838
 839         usb_ep_free_request(io_data->ep, io_data->req);
 840
 841         if (io_data->read)
 842                 kfree(io_data->to_free);
 843         ffs_free_buffer(io_data);
 844         kfree(io_data);
 845 }
 846
 847 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 848                                          struct usb_request *req)
 849 {
 850         struct ffs_io_data *io_data = req->context;
 851         struct ffs_data *ffs = io_data->ffs;
 852
 853         ENTER();
 854
 855         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 856         queue_work(ffs->io_completion_wq, &io_data->work);
 857 }
 858
 859 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 860 {
 861         /*
 862          * See comment in struct ffs_epfile for full read_buffer pointer
 863          * synchronisation story.
 864          */
 865         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 866         if (buf && buf != READ_BUFFER_DROP)
 867                 kfree(buf);
 868 }
 869
 870 /* Assumes epfile->mutex is held. */
 871 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 872                                           struct iov_iter *iter)
 873 {
 874         /*
 875          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 876          * the buffer while we are using it.  See comment in struct ffs_epfile
 877          * for full read_buffer pointer synchronisation story.
 878          */
 879         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 880         ssize_t ret;
 881         if (!buf || buf == READ_BUFFER_DROP)
 882                 return 0;
 883
 884         ret = copy_to_iter(buf->data, buf->length, iter);
 885         if (buf->length == ret) {
 886                 kfree(buf);
 887                 return ret;
 888         }
 889
 890         if (unlikely(iov_iter_count(iter))) {
 891                 ret = -EFAULT;
 892         } else {
 893                 buf->length -= ret;
 894                 buf->data += ret;
 895         }
 896
 897         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 898                 kfree(buf);
 899
 900         return ret;
 901 }
 902
 903 /* Assumes epfile->mutex is held. */
 904 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 905                                       void *data, int data_len,
 906                                       struct iov_iter *iter)
 907 {
 908         struct ffs_buffer *buf;
 909
 910         ssize_t ret = copy_to_iter(data, data_len, iter);
 911         if (likely(data_len == ret))
 912                 return ret;
 913
 914         if (unlikely(iov_iter_count(iter)))
 915                 return -EFAULT;
 916
 917         /* See ffs_copy_to_iter for more context. */
 918         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 919                 data_len, ret);
 920
 921         data_len -= ret;
 922         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 923         if (!buf)
 924                 return -ENOMEM;
 925         buf->length = data_len;
 926         buf->data = buf->storage;
 927         memcpy(buf->storage, data + ret, data_len);
 928
 929         /*
 930          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 931          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 932          * in struct ffs_epfile for full read_buffer pointer synchronisation
 933          * story.
 934          */
 935         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 936                 kfree(buf);
 937
 938         return ret;
 939 }
 940
 941 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 942 {
 943         struct ffs_epfile *epfile = file->private_data;
 944         struct usb_request *req;
 945         struct ffs_ep *ep;
 946         char *data = NULL;
 947         ssize_t ret, data_len = -EINVAL;
 948         int halt;
 949
 950         /* Are we still active? */
 951         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 952                 return -ENODEV;
 953
 954         /* Wait for endpoint to be enabled */
 955         ep = epfile->ep;
 956         if (!ep) {
 957                 if (file->f_flags & O_NONBLOCK)
 958                         return -EAGAIN;
 959
 960                 ret = wait_event_interruptible(
 961                                 epfile->ffs->wait, (ep = epfile->ep));
 962                 if (ret)
 963                         return -EINTR;
 964         }
 965
 966         /* Do we halt? */
 967         halt = (!io_data->read == !epfile->in);
 968         if (halt && epfile->isoc)
 969                 return -EINVAL;
 970
 971         /* We will be using request and read_buffer */
 972         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 973         if (unlikely(ret))
 974                 goto error;
 975
 976         /* Allocate & copy */
 977         if (!halt) {
 978                 struct usb_gadget *gadget;
 979
 980                 /*
 981                  * Do we have buffered data from previous partial read?  Check
 982                  * that for synchronous case only because we do not have
 983                  * facility to ‘wake up’ a pending asynchronous read and push
 984                  * buffered data to it which we would need to make things behave
 985                  * consistently.
 986                  */
 987                 if (!io_data->aio && io_data->read) {
 988                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 989                         if (ret)
 990                                 goto error_mutex;
 991                 }
 992
 993                 /*
 994                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 995                  * before the waiting completes, so do not assign to 'gadget'
 996                  * earlier
 997                  */
 998                 gadget = epfile->ffs->gadget;
 999
1000                 spin_lock_irq(&epfile->ffs->eps_lock);
1001                 /* In the meantime, endpoint got disabled or changed. */
1002                 if (epfile->ep != ep) {
1003                         ret = -ESHUTDOWN;
1004                         goto error_lock;
1005                 }
1006                 data_len = iov_iter_count(&io_data->data);
1007                 /*
1008                  * Controller may require buffer size to be aligned to
1009                  * maxpacketsize of an out endpoint.
1010                  */
1011                 if (io_data->read)
1012                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1013
1014                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1015                 spin_unlock_irq(&epfile->ffs->eps_lock);
1016
1017                 data = ffs_alloc_buffer(io_data, data_len);
1018                 if (unlikely(!data)) {
1019                         ret = -ENOMEM;
1020                         goto error_mutex;
1021                 }
1022                 if (!io_data->read &&
1023                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1024                         ret = -EFAULT;
1025                         goto error_mutex;
1026                 }
1027         }
1028
1029         spin_lock_irq(&epfile->ffs->eps_lock);
1030
1031         if (epfile->ep != ep) {
1032                 /* In the meantime, endpoint got disabled or changed. */
1033                 ret = -ESHUTDOWN;
1034         } else if (halt) {
1035                 ret = usb_ep_set_halt(ep->ep);
1036                 if (!ret)
1037                         ret = -EBADMSG;
1038         } else if (unlikely(data_len == -EINVAL)) {
1039                 /*
1040                  * Sanity Check: even though data_len can't be used
1041                  * uninitialized at the time I write this comment, some
1042                  * compilers complain about this situation.
1043                  * In order to keep the code clean from warnings, data_len is
1044                  * being initialized to -EINVAL during its declaration, which
1045                  * means we can't rely on compiler anymore to warn no future
1046                  * changes won't result in data_len being used uninitialized.
1047                  * For such reason, we're adding this redundant sanity check
1048                  * here.
1049                  */
1050                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1051                 ret = -EINVAL;
1052         } else if (!io_data->aio) {
1053                 DECLARE_COMPLETION_ONSTACK(done);
1054                 bool interrupted = false;
1055
1056                 req = ep->req;
1057                 if (io_data->use_sg) {
1058                         req->buf = NULL;
1059                         req->sg = io_data->sgt.sgl;
1060                         req->num_sgs = io_data->sgt.nents;
1061                 } else {
1062                         req->buf = data;
1063                         req->num_sgs = 0;
1064                 }
1065                 req->length = data_len;
1066
1067                 io_data->buf = data;
1068
1069                 req->context  = &done;
1070                 req->complete = ffs_epfile_io_complete;
1071
1072                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1073                 if (unlikely(ret < 0))
1074                         goto error_lock;
1075
1076                 spin_unlock_irq(&epfile->ffs->eps_lock);
1077
1078                 if (unlikely(wait_for_completion_interruptible(&done))) {
1079                         /*
1080                          * To avoid race condition with ffs_epfile_io_complete,
1081                          * dequeue the request first then check
1082                          * status. usb_ep_dequeue API should guarantee no race
1083                          * condition with req->complete callback.
1084                          */
1085                         usb_ep_dequeue(ep->ep, req);
1086                         wait_for_completion(&done);
1087                         interrupted = ep->status < 0;
1088                 }
1089
1090                 if (interrupted)
1091                         ret = -EINTR;
1092                 else if (io_data->read && ep->status > 0)
1093                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1094                                                      &io_data->data);
1095                 else
1096                         ret = ep->status;
1097                 goto error_mutex;
1098         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1099                 ret = -ENOMEM;
1100         } else {
1101                 if (io_data->use_sg) {
1102                         req->buf = NULL;
1103                         req->sg = io_data->sgt.sgl;
1104                         req->num_sgs = io_data->sgt.nents;
1105                 } else {
1106                         req->buf = data;
1107                         req->num_sgs = 0;
1108                 }
1109                 req->length = data_len;
1110
1111                 io_data->buf = data;
1112                 io_data->ep = ep->ep;
1113                 io_data->req = req;
1114                 io_data->ffs = epfile->ffs;
1115
1116                 req->context  = io_data;
1117                 req->complete = ffs_epfile_async_io_complete;
1118
1119                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1120                 if (unlikely(ret)) {
1121                         io_data->req = NULL;
1122                         usb_ep_free_request(ep->ep, req);
1123                         goto error_lock;
1124                 }
1125
1126                 ret = -EIOCBQUEUED;
1127                 /*
1128                  * Do not kfree the buffer in this function.  It will be freed
1129                  * by ffs_user_copy_worker.
1130                  */
1131                 data = NULL;
1132         }
1133
1134 error_lock:
1135         spin_unlock_irq(&epfile->ffs->eps_lock);
1136 error_mutex:
1137         mutex_unlock(&epfile->mutex);
1138 error:
1139         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1140                 ffs_free_buffer(io_data);
1141         return ret;
1142 }
1143
1144 static int
1145 ffs_epfile_open(struct inode *inode, struct file *file)
1146 {
1147         struct ffs_epfile *epfile = inode->i_private;
1148
1149         ENTER();
1150
1151         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1152                 return -ENODEV;
1153
1154         file->private_data = epfile;
1155         ffs_data_opened(epfile->ffs);
1156
1157         return 0;
1158 }
1159
1160 static int ffs_aio_cancel(struct kiocb *kiocb)
1161 {
1162         struct ffs_io_data *io_data = kiocb->private;
1163         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1164         unsigned long flags;
1165         int value;
1166
1167         ENTER();
1168
1169         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1170
1171         if (likely(io_data && io_data->ep && io_data->req))
1172                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1173         else
1174                 value = -EINVAL;
1175
1176         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1177
1178         return value;
1179 }
1180
1181 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1182 {
1183         struct ffs_io_data io_data, *p = &io_data;
1184         ssize_t res;
1185
1186         ENTER();
1187
1188         if (!is_sync_kiocb(kiocb)) {
1189                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1190                 if (unlikely(!p))
1191                         return -ENOMEM;
1192                 p->aio = true;
1193         } else {
1194                 memset(p, 0, sizeof(*p));
1195                 p->aio = false;
1196         }
1197
1198         p->read = false;
1199         p->kiocb = kiocb;
1200         p->data = *from;
1201         p->mm = current->mm;
1202
1203         kiocb->private = p;
1204
1205         if (p->aio)
1206                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1207
1208         res = ffs_epfile_io(kiocb->ki_filp, p);
1209         if (res == -EIOCBQUEUED)
1210                 return res;
1211         if (p->aio)
1212                 kfree(p);
1213         else
1214                 *from = p->data;
1215         return res;
1216 }
1217
1218 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1219 {
1220         struct ffs_io_data io_data, *p = &io_data;
1221         ssize_t res;
1222
1223         ENTER();
1224
1225         if (!is_sync_kiocb(kiocb)) {
1226                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1227                 if (unlikely(!p))
1228                         return -ENOMEM;
1229                 p->aio = true;
1230         } else {
1231                 memset(p, 0, sizeof(*p));
1232                 p->aio = false;
1233         }
1234
1235         p->read = true;
1236         p->kiocb = kiocb;
1237         if (p->aio) {
1238                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1239                 if (!p->to_free) {
1240                         kfree(p);
1241                         return -ENOMEM;
1242                 }
1243         } else {
1244                 p->data = *to;
1245                 p->to_free = NULL;
1246         }
1247         p->mm = current->mm;
1248
1249         kiocb->private = p;
1250
1251         if (p->aio)
1252                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1253
1254         res = ffs_epfile_io(kiocb->ki_filp, p);
1255         if (res == -EIOCBQUEUED)
1256                 return res;
1257
1258         if (p->aio) {
1259                 kfree(p->to_free);
1260                 kfree(p);
1261         } else {
1262                 *to = p->data;
1263         }
1264         return res;
1265 }
1266
1267 static int
1268 ffs_epfile_release(struct inode *inode, struct file *file)
1269 {
1270         struct ffs_epfile *epfile = inode->i_private;
1271
1272         ENTER();
1273
1274         __ffs_epfile_read_buffer_free(epfile);
1275         ffs_data_closed(epfile->ffs);
1276
1277         return 0;
1278 }
1279
1280 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1281                              unsigned long value)
1282 {
1283         struct ffs_epfile *epfile = file->private_data;
1284         struct ffs_ep *ep;
1285         int ret;
1286
1287         ENTER();
1288
1289         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1290                 return -ENODEV;
1291
1292         /* Wait for endpoint to be enabled */
1293         ep = epfile->ep;
1294         if (!ep) {
1295                 if (file->f_flags & O_NONBLOCK)
1296                         return -EAGAIN;
1297
1298                 ret = wait_event_interruptible(
1299                                 epfile->ffs->wait, (ep = epfile->ep));
1300                 if (ret)
1301                         return -EINTR;
1302         }
1303
1304         spin_lock_irq(&epfile->ffs->eps_lock);
1305
1306         /* In the meantime, endpoint got disabled or changed. */
1307         if (epfile->ep != ep) {
1308                 spin_unlock_irq(&epfile->ffs->eps_lock);
1309                 return -ESHUTDOWN;
1310         }
1311
1312         switch (code) {
1313         case FUNCTIONFS_FIFO_STATUS:
1314                 ret = usb_ep_fifo_status(epfile->ep->ep);
1315                 break;
1316         case FUNCTIONFS_FIFO_FLUSH:
1317                 usb_ep_fifo_flush(epfile->ep->ep);
1318                 ret = 0;
1319                 break;
1320         case FUNCTIONFS_CLEAR_HALT:
1321                 ret = usb_ep_clear_halt(epfile->ep->ep);
1322                 break;
1323         case FUNCTIONFS_ENDPOINT_REVMAP:
1324                 ret = epfile->ep->num;
1325                 break;
1326         case FUNCTIONFS_ENDPOINT_DESC:
1327         {
1328                 int desc_idx;
1329                 struct usb_endpoint_descriptor *desc;
1330
1331                 switch (epfile->ffs->gadget->speed) {
1332                 case USB_SPEED_SUPER:
1333                         desc_idx = 2;
1334                         break;
1335                 case USB_SPEED_HIGH:
1336                         desc_idx = 1;
1337                         break;
1338                 default:
1339                         desc_idx = 0;
1340                 }
1341                 desc = epfile->ep->descs[desc_idx];
1342
1343                 spin_unlock_irq(&epfile->ffs->eps_lock);
1344                 ret = copy_to_user((void __user *)value, desc, desc->bLength);
1345                 if (ret)
1346                         ret = -EFAULT;
1347                 return ret;
1348         }
1349         default:
1350                 ret = -ENOTTY;
1351         }
1352         spin_unlock_irq(&epfile->ffs->eps_lock);
1353
1354         return ret;
1355 }
1356
1357 static const struct file_operations ffs_epfile_operations = {
1358         .llseek =       no_llseek,
1359
1360         .open =         ffs_epfile_open,
1361         .write_iter =   ffs_epfile_write_iter,
1362         .read_iter =    ffs_epfile_read_iter,
1363         .release =      ffs_epfile_release,
1364         .unlocked_ioctl =       ffs_epfile_ioctl,
1365         .compat_ioctl = compat_ptr_ioctl,
1366 };
1367
1368
1369 /* File system and super block operations ***********************************/
1370
1371 /*
1372  * Mounting the file system creates a controller file, used first for
1373  * function configuration then later for event monitoring.
1374  */
1375
1376 static struct inode *__must_check
1377 ffs_sb_make_inode(struct super_block *sb, void *data,
1378                   const struct file_operations *fops,
1379                   const struct inode_operations *iops,
1380                   struct ffs_file_perms *perms)
1381 {
1382         struct inode *inode;
1383
1384         ENTER();
1385
1386         inode = new_inode(sb);
1387
1388         if (likely(inode)) {
1389                 struct timespec64 ts = current_time(inode);
1390
1391                 inode->i_ino     = get_next_ino();
1392                 inode->i_mode    = perms->mode;
1393                 inode->i_uid     = perms->uid;
1394                 inode->i_gid     = perms->gid;
1395                 inode->i_atime   = ts;
1396                 inode->i_mtime   = ts;
1397                 inode->i_ctime   = ts;
1398                 inode->i_private = data;
1399                 if (fops)
1400                         inode->i_fop = fops;
1401                 if (iops)
1402                         inode->i_op  = iops;
1403         }
1404
1405         return inode;
1406 }
1407
1408 /* Create "regular" file */
1409 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1410                                         const char *name, void *data,
1411                                         const struct file_operations *fops)
1412 {
1413         struct ffs_data *ffs = sb->s_fs_info;
1414         struct dentry   *dentry;
1415         struct inode    *inode;
1416
1417         ENTER();
1418
1419         dentry = d_alloc_name(sb->s_root, name);
1420         if (unlikely(!dentry))
1421                 return NULL;
1422
1423         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1424         if (unlikely(!inode)) {
1425                 dput(dentry);
1426                 return NULL;
1427         }
1428
1429         d_add(dentry, inode);
1430         return dentry;
1431 }
1432
1433 /* Super block */
1434 static const struct super_operations ffs_sb_operations = {
1435         .statfs =       simple_statfs,
1436         .drop_inode =   generic_delete_inode,
1437 };
1438
1439 struct ffs_sb_fill_data {
1440         struct ffs_file_perms perms;
1441         umode_t root_mode;
1442         const char *dev_name;
1443         bool no_disconnect;
1444         struct ffs_data *ffs_data;
1445 };
1446
1447 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1448 {
1449         struct ffs_sb_fill_data *data = fc->fs_private;
1450         struct inode    *inode;
1451         struct ffs_data *ffs = data->ffs_data;
1452
1453         ENTER();
1454
1455         ffs->sb              = sb;
1456         data->ffs_data       = NULL;
1457         sb->s_fs_info        = ffs;
1458         sb->s_blocksize      = PAGE_SIZE;
1459         sb->s_blocksize_bits = PAGE_SHIFT;
1460         sb->s_magic          = FUNCTIONFS_MAGIC;
1461         sb->s_op             = &ffs_sb_operations;
1462         sb->s_time_gran      = 1;
1463
1464         /* Root inode */
1465         data->perms.mode = data->root_mode;
1466         inode = ffs_sb_make_inode(sb, NULL,
1467                                   &simple_dir_operations,
1468                                   &simple_dir_inode_operations,
1469                                   &data->perms);
1470         sb->s_root = d_make_root(inode);
1471         if (unlikely(!sb->s_root))
1472                 return -ENOMEM;
1473
1474         /* EP0 file */
1475         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1476                                          &ffs_ep0_operations)))
1477                 return -ENOMEM;
1478
1479         return 0;
1480 }
1481
1482 enum {
1483         Opt_no_disconnect,
1484         Opt_rmode,
1485         Opt_fmode,
1486         Opt_mode,
1487         Opt_uid,
1488         Opt_gid,
1489 };
1490
1491 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1492         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1493         fsparam_u32     ("rmode",               Opt_rmode),
1494         fsparam_u32     ("fmode",               Opt_fmode),
1495         fsparam_u32     ("mode",                Opt_mode),
1496         fsparam_u32     ("uid",                 Opt_uid),
1497         fsparam_u32     ("gid",                 Opt_gid),
1498         {}
1499 };
1500
1501 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1502 {
1503         struct ffs_sb_fill_data *data = fc->fs_private;
1504         struct fs_parse_result result;
1505         int opt;
1506
1507         ENTER();
1508
1509         opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1510         if (opt < 0)
1511                 return opt;
1512
1513         switch (opt) {
1514         case Opt_no_disconnect:
1515                 data->no_disconnect = result.boolean;
1516                 break;
1517         case Opt_rmode:
1518                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1519                 break;
1520         case Opt_fmode:
1521                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1522                 break;
1523         case Opt_mode:
1524                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1525                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1526                 break;
1527
1528         case Opt_uid:
1529                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1530                 if (!uid_valid(data->perms.uid))
1531                         goto unmapped_value;
1532                 break;
1533         case Opt_gid:
1534                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1535                 if (!gid_valid(data->perms.gid))
1536                         goto unmapped_value;
1537                 break;
1538
1539         default:
1540                 return -ENOPARAM;
1541         }
1542
1543         return 0;
1544
1545 unmapped_value:
1546         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1547 }
1548
1549 /*
1550  * Set up the superblock for a mount.
1551  */
1552 static int ffs_fs_get_tree(struct fs_context *fc)
1553 {
1554         struct ffs_sb_fill_data *ctx = fc->fs_private;
1555         void *ffs_dev;
1556         struct ffs_data *ffs;
1557
1558         ENTER();
1559
1560         if (!fc->source)
1561                 return invalf(fc, "No source specified");
1562
1563         ffs = ffs_data_new(fc->source);
1564         if (unlikely(!ffs))
1565                 return -ENOMEM;
1566         ffs->file_perms = ctx->perms;
1567         ffs->no_disconnect = ctx->no_disconnect;
1568
1569         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1570         if (unlikely(!ffs->dev_name)) {
1571                 ffs_data_put(ffs);
1572                 return -ENOMEM;
1573         }
1574
1575         ffs_dev = ffs_acquire_dev(ffs->dev_name);
1576         if (IS_ERR(ffs_dev)) {
1577                 ffs_data_put(ffs);
1578                 return PTR_ERR(ffs_dev);
1579         }
1580
1581         ffs->private_data = ffs_dev;
1582         ctx->ffs_data = ffs;
1583         return get_tree_nodev(fc, ffs_sb_fill);
1584 }
1585
1586 static void ffs_fs_free_fc(struct fs_context *fc)
1587 {
1588         struct ffs_sb_fill_data *ctx = fc->fs_private;
1589
1590         if (ctx) {
1591                 if (ctx->ffs_data) {
1592                         ffs_release_dev(ctx->ffs_data);
1593                         ffs_data_put(ctx->ffs_data);
1594                 }
1595
1596                 kfree(ctx);
1597         }
1598 }
1599
1600 static const struct fs_context_operations ffs_fs_context_ops = {
1601         .free           = ffs_fs_free_fc,
1602         .parse_param    = ffs_fs_parse_param,
1603         .get_tree       = ffs_fs_get_tree,
1604 };
1605
1606 static int ffs_fs_init_fs_context(struct fs_context *fc)
1607 {
1608         struct ffs_sb_fill_data *ctx;
1609
1610         ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1611         if (!ctx)
1612                 return -ENOMEM;
1613
1614         ctx->perms.mode = S_IFREG | 0600;
1615         ctx->perms.uid = GLOBAL_ROOT_UID;
1616         ctx->perms.gid = GLOBAL_ROOT_GID;
1617         ctx->root_mode = S_IFDIR | 0500;
1618         ctx->no_disconnect = false;
1619
1620         fc->fs_private = ctx;
1621         fc->ops = &ffs_fs_context_ops;
1622         return 0;
1623 }
1624
1625 static void
1626 ffs_fs_kill_sb(struct super_block *sb)
1627 {
1628         ENTER();
1629
1630         kill_litter_super(sb);
1631         if (sb->s_fs_info) {
1632                 ffs_release_dev(sb->s_fs_info);
1633                 ffs_data_closed(sb->s_fs_info);
1634         }
1635 }
1636
1637 static struct file_system_type ffs_fs_type = {
1638         .owner          = THIS_MODULE,
1639         .name           = "functionfs",
1640         .init_fs_context = ffs_fs_init_fs_context,
1641         .parameters     = ffs_fs_fs_parameters,
1642         .kill_sb        = ffs_fs_kill_sb,
1643 };
1644 MODULE_ALIAS_FS("functionfs");
1645
1646
1647 /* Driver's main init/cleanup functions *************************************/
1648
1649 static int functionfs_init(void)
1650 {
1651         int ret;
1652
1653         ENTER();
1654
1655         ret = register_filesystem(&ffs_fs_type);
1656         if (likely(!ret))
1657                 pr_info("file system registered\n");
1658         else
1659                 pr_err("failed registering file system (%d)\n", ret);
1660
1661         return ret;
1662 }
1663
1664 static void functionfs_cleanup(void)
1665 {
1666         ENTER();
1667
1668         pr_info("unloading\n");
1669         unregister_filesystem(&ffs_fs_type);
1670 }
1671
1672
1673 /* ffs_data and ffs_function construction and destruction code **************/
1674
1675 static void ffs_data_clear(struct ffs_data *ffs);
1676 static void ffs_data_reset(struct ffs_data *ffs);
1677
1678 static void ffs_data_get(struct ffs_data *ffs)
1679 {
1680         ENTER();
1681
1682         refcount_inc(&ffs->ref);
1683 }
1684
1685 static void ffs_data_opened(struct ffs_data *ffs)
1686 {
1687         ENTER();
1688
1689         refcount_inc(&ffs->ref);
1690         if (atomic_add_return(1, &ffs->opened) == 1 &&
1691                         ffs->state == FFS_DEACTIVATED) {
1692                 ffs->state = FFS_CLOSING;
1693                 ffs_data_reset(ffs);
1694         }
1695 }
1696
1697 static void ffs_data_put(struct ffs_data *ffs)
1698 {
1699         ENTER();
1700
1701         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1702                 pr_info("%s(): freeing\n", __func__);
1703                 ffs_data_clear(ffs);
1704                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1705                        swait_active(&ffs->ep0req_completion.wait) ||
1706                        waitqueue_active(&ffs->wait));
1707                 destroy_workqueue(ffs->io_completion_wq);
1708                 kfree(ffs->dev_name);
1709                 kfree(ffs);
1710         }
1711 }
1712
1713 static void ffs_data_closed(struct ffs_data *ffs)
1714 {
1715         ENTER();
1716
1717         if (atomic_dec_and_test(&ffs->opened)) {
1718                 if (ffs->no_disconnect) {
1719                         ffs->state = FFS_DEACTIVATED;
1720                         if (ffs->epfiles) {
1721                                 ffs_epfiles_destroy(ffs->epfiles,
1722                                                    ffs->eps_count);
1723                                 ffs->epfiles = NULL;
1724                         }
1725                         if (ffs->setup_state == FFS_SETUP_PENDING)
1726                                 __ffs_ep0_stall(ffs);
1727                 } else {
1728                         ffs->state = FFS_CLOSING;
1729                         ffs_data_reset(ffs);
1730                 }
1731         }
1732         if (atomic_read(&ffs->opened) < 0) {
1733                 ffs->state = FFS_CLOSING;
1734                 ffs_data_reset(ffs);
1735         }
1736
1737         ffs_data_put(ffs);
1738 }
1739
1740 static struct ffs_data *ffs_data_new(const char *dev_name)
1741 {
1742         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1743         if (unlikely(!ffs))
1744                 return NULL;
1745
1746         ENTER();
1747
1748         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1749         if (!ffs->io_completion_wq) {
1750                 kfree(ffs);
1751                 return NULL;
1752         }
1753
1754         refcount_set(&ffs->ref, 1);
1755         atomic_set(&ffs->opened, 0);
1756         ffs->state = FFS_READ_DESCRIPTORS;
1757         mutex_init(&ffs->mutex);
1758         spin_lock_init(&ffs->eps_lock);
1759         init_waitqueue_head(&ffs->ev.waitq);
1760         init_waitqueue_head(&ffs->wait);
1761         init_completion(&ffs->ep0req_completion);
1762
1763         /* XXX REVISIT need to update it in some places, or do we? */
1764         ffs->ev.can_stall = 1;
1765
1766         return ffs;
1767 }
1768
1769 static void ffs_data_clear(struct ffs_data *ffs)
1770 {
1771         ENTER();
1772
1773         ffs_closed(ffs);
1774
1775         BUG_ON(ffs->gadget);
1776
1777         if (ffs->epfiles)
1778                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1779
1780         if (ffs->ffs_eventfd)
1781                 eventfd_ctx_put(ffs->ffs_eventfd);
1782
1783         kfree(ffs->raw_descs_data);
1784         kfree(ffs->raw_strings);
1785         kfree(ffs->stringtabs);
1786 }
1787
1788 static void ffs_data_reset(struct ffs_data *ffs)
1789 {
1790         ENTER();
1791
1792         ffs_data_clear(ffs);
1793
1794         ffs->epfiles = NULL;
1795         ffs->raw_descs_data = NULL;
1796         ffs->raw_descs = NULL;
1797         ffs->raw_strings = NULL;
1798         ffs->stringtabs = NULL;
1799
1800         ffs->raw_descs_length = 0;
1801         ffs->fs_descs_count = 0;
1802         ffs->hs_descs_count = 0;
1803         ffs->ss_descs_count = 0;
1804
1805         ffs->strings_count = 0;
1806         ffs->interfaces_count = 0;
1807         ffs->eps_count = 0;
1808
1809         ffs->ev.count = 0;
1810
1811         ffs->state = FFS_READ_DESCRIPTORS;
1812         ffs->setup_state = FFS_NO_SETUP;
1813         ffs->flags = 0;
1814
1815         ffs->ms_os_descs_ext_prop_count = 0;
1816         ffs->ms_os_descs_ext_prop_name_len = 0;
1817         ffs->ms_os_descs_ext_prop_data_len = 0;
1818 }
1819
1820
1821 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1822 {
1823         struct usb_gadget_strings **lang;
1824         int first_id;
1825
1826         ENTER();
1827
1828         if (WARN_ON(ffs->state != FFS_ACTIVE
1829                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1830                 return -EBADFD;
1831
1832         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1833         if (unlikely(first_id < 0))
1834                 return first_id;
1835
1836         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1837         if (unlikely(!ffs->ep0req))
1838                 return -ENOMEM;
1839         ffs->ep0req->complete = ffs_ep0_complete;
1840         ffs->ep0req->context = ffs;
1841
1842         lang = ffs->stringtabs;
1843         if (lang) {
1844                 for (; *lang; ++lang) {
1845                         struct usb_string *str = (*lang)->strings;
1846                         int id = first_id;
1847                         for (; str->s; ++id, ++str)
1848                                 str->id = id;
1849                 }
1850         }
1851
1852         ffs->gadget = cdev->gadget;
1853         ffs_data_get(ffs);
1854         return 0;
1855 }
1856
1857 static void functionfs_unbind(struct ffs_data *ffs)
1858 {
1859         ENTER();
1860
1861         if (!WARN_ON(!ffs->gadget)) {
1862                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1863                 ffs->ep0req = NULL;
1864                 ffs->gadget = NULL;
1865                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1866                 ffs_data_put(ffs);
1867         }
1868 }
1869
1870 static int ffs_epfiles_create(struct ffs_data *ffs)
1871 {
1872         struct ffs_epfile *epfile, *epfiles;
1873         unsigned i, count;
1874
1875         ENTER();
1876
1877         count = ffs->eps_count;
1878         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1879         if (!epfiles)
1880                 return -ENOMEM;
1881
1882         epfile = epfiles;
1883         for (i = 1; i <= count; ++i, ++epfile) {
1884                 epfile->ffs = ffs;
1885                 mutex_init(&epfile->mutex);
1886                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1887                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1888                 else
1889                         sprintf(epfile->name, "ep%u", i);
1890                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1891                                                  epfile,
1892                                                  &ffs_epfile_operations);
1893                 if (unlikely(!epfile->dentry)) {
1894                         ffs_epfiles_destroy(epfiles, i - 1);
1895                         return -ENOMEM;
1896                 }
1897         }
1898
1899         ffs->epfiles = epfiles;
1900         return 0;
1901 }
1902
1903 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1904 {
1905         struct ffs_epfile *epfile = epfiles;
1906
1907         ENTER();
1908
1909         for (; count; --count, ++epfile) {
1910                 BUG_ON(mutex_is_locked(&epfile->mutex));
1911                 if (epfile->dentry) {
1912                         d_delete(epfile->dentry);
1913                         dput(epfile->dentry);
1914                         epfile->dentry = NULL;
1915                 }
1916         }
1917
1918         kfree(epfiles);
1919 }
1920
1921 static void ffs_func_eps_disable(struct ffs_function *func)
1922 {
1923         struct ffs_ep *ep         = func->eps;
1924         struct ffs_epfile *epfile = func->ffs->epfiles;
1925         unsigned count            = func->ffs->eps_count;
1926         unsigned long flags;
1927
1928         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1929         while (count--) {
1930                 /* pending requests get nuked */
1931                 if (likely(ep->ep))
1932                         usb_ep_disable(ep->ep);
1933                 ++ep;
1934
1935                 if (epfile) {
1936                         epfile->ep = NULL;
1937                         __ffs_epfile_read_buffer_free(epfile);
1938                         ++epfile;
1939                 }
1940         }
1941         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1942 }
1943
1944 static int ffs_func_eps_enable(struct ffs_function *func)
1945 {
1946         struct ffs_data *ffs      = func->ffs;
1947         struct ffs_ep *ep         = func->eps;
1948         struct ffs_epfile *epfile = ffs->epfiles;
1949         unsigned count            = ffs->eps_count;
1950         unsigned long flags;
1951         int ret = 0;
1952
1953         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1954         while(count--) {
1955                 ep->ep->driver_data = ep;
1956
1957                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1958                 if (ret) {
1959                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1960                                         __func__, ep->ep->name, ret);
1961                         break;
1962                 }
1963
1964                 ret = usb_ep_enable(ep->ep);
1965                 if (likely(!ret)) {
1966                         epfile->ep = ep;
1967                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1968                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1969                 } else {
1970                         break;
1971                 }
1972
1973                 ++ep;
1974                 ++epfile;
1975         }
1976
1977         wake_up_interruptible(&ffs->wait);
1978         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1979
1980         return ret;
1981 }
1982
1983
1984 /* Parsing and building descriptors and strings *****************************/
1985
1986 /*
1987  * This validates if data pointed by data is a valid USB descriptor as
1988  * well as record how many interfaces, endpoints and strings are
1989  * required by given configuration.  Returns address after the
1990  * descriptor or NULL if data is invalid.
1991  */
1992
1993 enum ffs_entity_type {
1994         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1995 };
1996
1997 enum ffs_os_desc_type {
1998         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1999 };
2000
2001 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2002                                    u8 *valuep,
2003                                    struct usb_descriptor_header *desc,
2004                                    void *priv);
2005
2006 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2007                                     struct usb_os_desc_header *h, void *data,
2008                                     unsigned len, void *priv);
2009
2010 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2011                                            ffs_entity_callback entity,
2012                                            void *priv, int *current_class)
2013 {
2014         struct usb_descriptor_header *_ds = (void *)data;
2015         u8 length;
2016         int ret;
2017
2018         ENTER();
2019
2020         /* At least two bytes are required: length and type */
2021         if (len < 2) {
2022                 pr_vdebug("descriptor too short\n");
2023                 return -EINVAL;
2024         }
2025
2026         /* If we have at least as many bytes as the descriptor takes? */
2027         length = _ds->bLength;
2028         if (len < length) {
2029                 pr_vdebug("descriptor longer then available data\n");
2030                 return -EINVAL;
2031         }
2032
2033 #define __entity_check_INTERFACE(val)  1
2034 #define __entity_check_STRING(val)     (val)
2035 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2036 #define __entity(type, val) do {                                        \
2037                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2038                 if (unlikely(!__entity_check_ ##type(val))) {           \
2039                         pr_vdebug("invalid entity's value\n");          \
2040                         return -EINVAL;                                 \
2041                 }                                                       \
2042                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2043                 if (unlikely(ret < 0)) {                                \
2044                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2045                                  (val), ret);                           \
2046                         return ret;                                     \
2047                 }                                                       \
2048         } while (0)
2049
2050         /* Parse descriptor depending on type. */
2051         switch (_ds->bDescriptorType) {
2052         case USB_DT_DEVICE:
2053         case USB_DT_CONFIG:
2054         case USB_DT_STRING:
2055         case USB_DT_DEVICE_QUALIFIER:
2056                 /* function can't have any of those */
2057                 pr_vdebug("descriptor reserved for gadget: %d\n",
2058                       _ds->bDescriptorType);
2059                 return -EINVAL;
2060
2061         case USB_DT_INTERFACE: {
2062                 struct usb_interface_descriptor *ds = (void *)_ds;
2063                 pr_vdebug("interface descriptor\n");
2064                 if (length != sizeof *ds)
2065                         goto inv_length;
2066
2067                 __entity(INTERFACE, ds->bInterfaceNumber);
2068                 if (ds->iInterface)
2069                         __entity(STRING, ds->iInterface);
2070                 *current_class = ds->bInterfaceClass;
2071         }
2072                 break;
2073
2074         case USB_DT_ENDPOINT: {
2075                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2076                 pr_vdebug("endpoint descriptor\n");
2077                 if (length != USB_DT_ENDPOINT_SIZE &&
2078                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2079                         goto inv_length;
2080                 __entity(ENDPOINT, ds->bEndpointAddress);
2081         }
2082                 break;
2083
2084         case USB_TYPE_CLASS | 0x01:
2085                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2086                         pr_vdebug("hid descriptor\n");
2087                         if (length != sizeof(struct hid_descriptor))
2088                                 goto inv_length;
2089                         break;
2090                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2091                         pr_vdebug("ccid descriptor\n");
2092                         if (length != sizeof(struct ccid_descriptor))
2093                                 goto inv_length;
2094                         break;
2095                 } else {
2096                         pr_vdebug("unknown descriptor: %d for class %d\n",
2097                               _ds->bDescriptorType, *current_class);
2098                         return -EINVAL;
2099                 }
2100
2101         case USB_DT_OTG:
2102                 if (length != sizeof(struct usb_otg_descriptor))
2103                         goto inv_length;
2104                 break;
2105
2106         case USB_DT_INTERFACE_ASSOCIATION: {
2107                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2108                 pr_vdebug("interface association descriptor\n");
2109                 if (length != sizeof *ds)
2110                         goto inv_length;
2111                 if (ds->iFunction)
2112                         __entity(STRING, ds->iFunction);
2113         }
2114                 break;
2115
2116         case USB_DT_SS_ENDPOINT_COMP:
2117                 pr_vdebug("EP SS companion descriptor\n");
2118                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2119                         goto inv_length;
2120                 break;
2121
2122         case USB_DT_OTHER_SPEED_CONFIG:
2123         case USB_DT_INTERFACE_POWER:
2124         case USB_DT_DEBUG:
2125         case USB_DT_SECURITY:
2126         case USB_DT_CS_RADIO_CONTROL:
2127                 /* TODO */
2128                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2129                 return -EINVAL;
2130
2131         default:
2132                 /* We should never be here */
2133                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2134                 return -EINVAL;
2135
2136 inv_length:
2137                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2138                           _ds->bLength, _ds->bDescriptorType);
2139                 return -EINVAL;
2140         }
2141
2142 #undef __entity
2143 #undef __entity_check_DESCRIPTOR
2144 #undef __entity_check_INTERFACE
2145 #undef __entity_check_STRING
2146 #undef __entity_check_ENDPOINT
2147
2148         return length;
2149 }
2150
2151 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2152                                      ffs_entity_callback entity, void *priv)
2153 {
2154         const unsigned _len = len;
2155         unsigned long num = 0;
2156         int current_class = -1;
2157
2158         ENTER();
2159
2160         for (;;) {
2161                 int ret;
2162
2163                 if (num == count)
2164                         data = NULL;
2165
2166                 /* Record "descriptor" entity */
2167                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2168                 if (unlikely(ret < 0)) {
2169                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2170                                  num, ret);
2171                         return ret;
2172                 }
2173
2174                 if (!data)
2175                         return _len - len;
2176
2177                 ret = ffs_do_single_desc(data, len, entity, priv,
2178                         &current_class);
2179                 if (unlikely(ret < 0)) {
2180                         pr_debug("%s returns %d\n", __func__, ret);
2181                         return ret;
2182                 }
2183
2184                 len -= ret;
2185                 data += ret;
2186                 ++num;
2187         }
2188 }
2189
2190 static int __ffs_data_do_entity(enum ffs_entity_type type,
2191                                 u8 *valuep, struct usb_descriptor_header *desc,
2192                                 void *priv)
2193 {
2194         struct ffs_desc_helper *helper = priv;
2195         struct usb_endpoint_descriptor *d;
2196
2197         ENTER();
2198
2199         switch (type) {
2200         case FFS_DESCRIPTOR:
2201                 break;
2202
2203         case FFS_INTERFACE:
2204                 /*
2205                  * Interfaces are indexed from zero so if we
2206                  * encountered interface "n" then there are at least
2207                  * "n+1" interfaces.
2208                  */
2209                 if (*valuep >= helper->interfaces_count)
2210                         helper->interfaces_count = *valuep + 1;
2211                 break;
2212
2213         case FFS_STRING:
2214                 /*
2215                  * Strings are indexed from 1 (0 is reserved
2216                  * for languages list)
2217                  */
2218                 if (*valuep > helper->ffs->strings_count)
2219                         helper->ffs->strings_count = *valuep;
2220                 break;
2221
2222         case FFS_ENDPOINT:
2223                 d = (void *)desc;
2224                 helper->eps_count++;
2225                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2226                         return -EINVAL;
2227                 /* Check if descriptors for any speed were already parsed */
2228                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2229                         helper->ffs->eps_addrmap[helper->eps_count] =
2230                                 d->bEndpointAddress;
2231                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2232                                 d->bEndpointAddress)
2233                         return -EINVAL;
2234                 break;
2235         }
2236
2237         return 0;
2238 }
2239
2240 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2241                                    struct usb_os_desc_header *desc)
2242 {
2243         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2244         u16 w_index = le16_to_cpu(desc->wIndex);
2245
2246         if (bcd_version != 1) {
2247                 pr_vdebug("unsupported os descriptors version: %d",
2248                           bcd_version);
2249                 return -EINVAL;
2250         }
2251         switch (w_index) {
2252         case 0x4:
2253                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2254                 break;
2255         case 0x5:
2256                 *next_type = FFS_OS_DESC_EXT_PROP;
2257                 break;
2258         default:
2259                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2260                 return -EINVAL;
2261         }
2262
2263         return sizeof(*desc);
2264 }
2265
2266 /*
2267  * Process all extended compatibility/extended property descriptors
2268  * of a feature descriptor
2269  */
2270 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2271                                               enum ffs_os_desc_type type,
2272                                               u16 feature_count,
2273                                               ffs_os_desc_callback entity,
2274                                               void *priv,
2275                                               struct usb_os_desc_header *h)
2276 {
2277         int ret;
2278         const unsigned _len = len;
2279
2280         ENTER();
2281
2282         /* loop over all ext compat/ext prop descriptors */
2283         while (feature_count--) {
2284                 ret = entity(type, h, data, len, priv);
2285                 if (unlikely(ret < 0)) {
2286                         pr_debug("bad OS descriptor, type: %d\n", type);
2287                         return ret;
2288                 }
2289                 data += ret;
2290                 len -= ret;
2291         }
2292         return _len - len;
2293 }
2294
2295 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2296 static int __must_check ffs_do_os_descs(unsigned count,
2297                                         char *data, unsigned len,
2298                                         ffs_os_desc_callback entity, void *priv)
2299 {
2300         const unsigned _len = len;
2301         unsigned long num = 0;
2302
2303         ENTER();
2304
2305         for (num = 0; num < count; ++num) {
2306                 int ret;
2307                 enum ffs_os_desc_type type;
2308                 u16 feature_count;
2309                 struct usb_os_desc_header *desc = (void *)data;
2310
2311                 if (len < sizeof(*desc))
2312                         return -EINVAL;
2313
2314                 /*
2315                  * Record "descriptor" entity.
2316                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2317                  * Move the data pointer to the beginning of extended
2318                  * compatibilities proper or extended properties proper
2319                  * portions of the data
2320                  */
2321                 if (le32_to_cpu(desc->dwLength) > len)
2322                         return -EINVAL;
2323
2324                 ret = __ffs_do_os_desc_header(&type, desc);
2325                 if (unlikely(ret < 0)) {
2326                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2327                                  num, ret);
2328                         return ret;
2329                 }
2330                 /*
2331                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2332                  */
2333                 feature_count = le16_to_cpu(desc->wCount);
2334                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2335                     (feature_count > 255 || desc->Reserved))
2336                                 return -EINVAL;
2337                 len -= ret;
2338                 data += ret;
2339
2340                 /*
2341                  * Process all function/property descriptors
2342                  * of this Feature Descriptor
2343                  */
2344                 ret = ffs_do_single_os_desc(data, len, type,
2345                                             feature_count, entity, priv, desc);
2346                 if (unlikely(ret < 0)) {
2347                         pr_debug("%s returns %d\n", __func__, ret);
2348                         return ret;
2349                 }
2350
2351                 len -= ret;
2352                 data += ret;
2353         }
2354         return _len - len;
2355 }
2356
2357 /*
2358  * Validate contents of the buffer from userspace related to OS descriptors.
2359  */
2360 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2361                                  struct usb_os_desc_header *h, void *data,
2362                                  unsigned len, void *priv)
2363 {
2364         struct ffs_data *ffs = priv;
2365         u8 length;
2366
2367         ENTER();
2368
2369         switch (type) {
2370         case FFS_OS_DESC_EXT_COMPAT: {
2371                 struct usb_ext_compat_desc *d = data;
2372                 int i;
2373
2374                 if (len < sizeof(*d) ||
2375                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2376                         return -EINVAL;
2377                 if (d->Reserved1 != 1) {
2378                         /*
2379                          * According to the spec, Reserved1 must be set to 1
2380                          * but older kernels incorrectly rejected non-zero
2381                          * values.  We fix it here to avoid returning EINVAL
2382                          * in response to values we used to accept.
2383                          */
2384                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2385                         d->Reserved1 = 1;
2386                 }
2387                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2388                         if (d->Reserved2[i])
2389                                 return -EINVAL;
2390
2391                 length = sizeof(struct usb_ext_compat_desc);
2392         }
2393                 break;
2394         case FFS_OS_DESC_EXT_PROP: {
2395                 struct usb_ext_prop_desc *d = data;
2396                 u32 type, pdl;
2397                 u16 pnl;
2398
2399                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2400                         return -EINVAL;
2401                 length = le32_to_cpu(d->dwSize);
2402                 if (len < length)
2403                         return -EINVAL;
2404                 type = le32_to_cpu(d->dwPropertyDataType);
2405                 if (type < USB_EXT_PROP_UNICODE ||
2406                     type > USB_EXT_PROP_UNICODE_MULTI) {
2407                         pr_vdebug("unsupported os descriptor property type: %d",
2408                                   type);
2409                         return -EINVAL;
2410                 }
2411                 pnl = le16_to_cpu(d->wPropertyNameLength);
2412                 if (length < 14 + pnl) {
2413                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2414                                   length, pnl, type);
2415                         return -EINVAL;
2416                 }
2417                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2418                 if (length != 14 + pnl + pdl) {
2419                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2420                                   length, pnl, pdl, type);
2421                         return -EINVAL;
2422                 }
2423                 ++ffs->ms_os_descs_ext_prop_count;
2424                 /* property name reported to the host as "WCHAR"s */
2425                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2426                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2427         }
2428                 break;
2429         default:
2430                 pr_vdebug("unknown descriptor: %d\n", type);
2431                 return -EINVAL;
2432         }
2433         return length;
2434 }
2435
2436 static int __ffs_data_got_descs(struct ffs_data *ffs,
2437                                 char *const _data, size_t len)
2438 {
2439         char *data = _data, *raw_descs;
2440         unsigned os_descs_count = 0, counts[3], flags;
2441         int ret = -EINVAL, i;
2442         struct ffs_desc_helper helper;
2443
2444         ENTER();
2445
2446         if (get_unaligned_le32(data + 4) != len)
2447                 goto error;
2448
2449         switch (get_unaligned_le32(data)) {
2450         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2451                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2452                 data += 8;
2453                 len  -= 8;
2454                 break;
2455         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2456                 flags = get_unaligned_le32(data + 8);
2457                 ffs->user_flags = flags;
2458                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2459                               FUNCTIONFS_HAS_HS_DESC |
2460                               FUNCTIONFS_HAS_SS_DESC |
2461                               FUNCTIONFS_HAS_MS_OS_DESC |
2462                               FUNCTIONFS_VIRTUAL_ADDR |
2463                               FUNCTIONFS_EVENTFD |
2464                               FUNCTIONFS_ALL_CTRL_RECIP |
2465                               FUNCTIONFS_CONFIG0_SETUP)) {
2466                         ret = -ENOSYS;
2467                         goto error;
2468                 }
2469                 data += 12;
2470                 len  -= 12;
2471                 break;
2472         default:
2473                 goto error;
2474         }
2475
2476         if (flags & FUNCTIONFS_EVENTFD) {
2477                 if (len < 4)
2478                         goto error;
2479                 ffs->ffs_eventfd =
2480                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2481                 if (IS_ERR(ffs->ffs_eventfd)) {
2482                         ret = PTR_ERR(ffs->ffs_eventfd);
2483                         ffs->ffs_eventfd = NULL;
2484                         goto error;
2485                 }
2486                 data += 4;
2487                 len  -= 4;
2488         }
2489
2490         /* Read fs_count, hs_count and ss_count (if present) */
2491         for (i = 0; i < 3; ++i) {
2492                 if (!(flags & (1 << i))) {
2493                         counts[i] = 0;
2494                 } else if (len < 4) {
2495                         goto error;
2496                 } else {
2497                         counts[i] = get_unaligned_le32(data);
2498                         data += 4;
2499                         len  -= 4;
2500                 }
2501         }
2502         if (flags & (1 << i)) {
2503                 if (len < 4) {
2504                         goto error;
2505                 }
2506                 os_descs_count = get_unaligned_le32(data);
2507                 data += 4;
2508                 len -= 4;
2509         }
2510
2511         /* Read descriptors */
2512         raw_descs = data;
2513         helper.ffs = ffs;
2514         for (i = 0; i < 3; ++i) {
2515                 if (!counts[i])
2516                         continue;
2517                 helper.interfaces_count = 0;
2518                 helper.eps_count = 0;
2519                 ret = ffs_do_descs(counts[i], data, len,
2520                                    __ffs_data_do_entity, &helper);
2521                 if (ret < 0)
2522                         goto error;
2523                 if (!ffs->eps_count && !ffs->interfaces_count) {
2524                         ffs->eps_count = helper.eps_count;
2525                         ffs->interfaces_count = helper.interfaces_count;
2526                 } else {
2527                         if (ffs->eps_count != helper.eps_count) {
2528                                 ret = -EINVAL;
2529                                 goto error;
2530                         }
2531                         if (ffs->interfaces_count != helper.interfaces_count) {
2532                                 ret = -EINVAL;
2533                                 goto error;
2534                         }
2535                 }
2536                 data += ret;
2537                 len  -= ret;
2538         }
2539         if (os_descs_count) {
2540                 ret = ffs_do_os_descs(os_descs_count, data, len,
2541                                       __ffs_data_do_os_desc, ffs);
2542                 if (ret < 0)
2543                         goto error;
2544                 data += ret;
2545                 len -= ret;
2546         }
2547
2548         if (raw_descs == data || len) {
2549                 ret = -EINVAL;
2550                 goto error;
2551         }
2552
2553         ffs->raw_descs_data     = _data;
2554         ffs->raw_descs          = raw_descs;
2555         ffs->raw_descs_length   = data - raw_descs;
2556         ffs->fs_descs_count     = counts[0];
2557         ffs->hs_descs_count     = counts[1];
2558         ffs->ss_descs_count     = counts[2];
2559         ffs->ms_os_descs_count  = os_descs_count;
2560
2561         return 0;
2562
2563 error:
2564         kfree(_data);
2565         return ret;
2566 }
2567
2568 static int __ffs_data_got_strings(struct ffs_data *ffs,
2569                                   char *const _data, size_t len)
2570 {
2571         u32 str_count, needed_count, lang_count;
2572         struct usb_gadget_strings **stringtabs, *t;
2573         const char *data = _data;
2574         struct usb_string *s;
2575
2576         ENTER();
2577
2578         if (unlikely(len < 16 ||
2579                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2580                      get_unaligned_le32(data + 4) != len))
2581                 goto error;
2582         str_count  = get_unaligned_le32(data + 8);
2583         lang_count = get_unaligned_le32(data + 12);
2584
2585         /* if one is zero the other must be zero */
2586         if (unlikely(!str_count != !lang_count))
2587                 goto error;
2588
2589         /* Do we have at least as many strings as descriptors need? */
2590         needed_count = ffs->strings_count;
2591         if (unlikely(str_count < needed_count))
2592                 goto error;
2593
2594         /*
2595          * If we don't need any strings just return and free all
2596          * memory.
2597          */
2598         if (!needed_count) {
2599                 kfree(_data);
2600                 return 0;
2601         }
2602
2603         /* Allocate everything in one chunk so there's less maintenance. */
2604         {
2605                 unsigned i = 0;
2606                 vla_group(d);
2607                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2608                         lang_count + 1);
2609                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2610                 vla_item(d, struct usb_string, strings,
2611                         lang_count*(needed_count+1));
2612
2613                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2614
2615                 if (unlikely(!vlabuf)) {
2616                         kfree(_data);
2617                         return -ENOMEM;
2618                 }
2619
2620                 /* Initialize the VLA pointers */
2621                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2622                 t = vla_ptr(vlabuf, d, stringtab);
2623                 i = lang_count;
2624                 do {
2625                         *stringtabs++ = t++;
2626                 } while (--i);
2627                 *stringtabs = NULL;
2628
2629                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2630                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2631                 t = vla_ptr(vlabuf, d, stringtab);
2632                 s = vla_ptr(vlabuf, d, strings);
2633         }
2634
2635         /* For each language */
2636         data += 16;
2637         len -= 16;
2638
2639         do { /* lang_count > 0 so we can use do-while */
2640                 unsigned needed = needed_count;
2641
2642                 if (unlikely(len < 3))
2643                         goto error_free;
2644                 t->language = get_unaligned_le16(data);
2645                 t->strings  = s;
2646                 ++t;
2647
2648                 data += 2;
2649                 len -= 2;
2650
2651                 /* For each string */
2652                 do { /* str_count > 0 so we can use do-while */
2653                         size_t length = strnlen(data, len);
2654
2655                         if (unlikely(length == len))
2656                                 goto error_free;
2657
2658                         /*
2659                          * User may provide more strings then we need,
2660                          * if that's the case we simply ignore the
2661                          * rest
2662                          */
2663                         if (likely(needed)) {
2664                                 /*
2665                                  * s->id will be set while adding
2666                                  * function to configuration so for
2667                                  * now just leave garbage here.
2668                                  */
2669                                 s->s = data;
2670                                 --needed;
2671                                 ++s;
2672                         }
2673
2674                         data += length + 1;
2675                         len -= length + 1;
2676                 } while (--str_count);
2677
2678                 s->id = 0;   /* terminator */
2679                 s->s = NULL;
2680                 ++s;
2681
2682         } while (--lang_count);
2683
2684         /* Some garbage left? */
2685         if (unlikely(len))
2686                 goto error_free;
2687
2688         /* Done! */
2689         ffs->stringtabs = stringtabs;
2690         ffs->raw_strings = _data;
2691
2692         return 0;
2693
2694 error_free:
2695         kfree(stringtabs);
2696 error:
2697         kfree(_data);
2698         return -EINVAL;
2699 }
2700
2701
2702 /* Events handling and management *******************************************/
2703
2704 static void __ffs_event_add(struct ffs_data *ffs,
2705                             enum usb_functionfs_event_type type)
2706 {
2707         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2708         int neg = 0;
2709
2710         /*
2711          * Abort any unhandled setup
2712          *
2713          * We do not need to worry about some cmpxchg() changing value
2714          * of ffs->setup_state without holding the lock because when
2715          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2716          * the source does nothing.
2717          */
2718         if (ffs->setup_state == FFS_SETUP_PENDING)
2719                 ffs->setup_state = FFS_SETUP_CANCELLED;
2720
2721         /*
2722          * Logic of this function guarantees that there are at most four pending
2723          * evens on ffs->ev.types queue.  This is important because the queue
2724          * has space for four elements only and __ffs_ep0_read_events function
2725          * depends on that limit as well.  If more event types are added, those
2726          * limits have to be revisited or guaranteed to still hold.
2727          */
2728         switch (type) {
2729         case FUNCTIONFS_RESUME:
2730                 rem_type2 = FUNCTIONFS_SUSPEND;
2731                 fallthrough;
2732         case FUNCTIONFS_SUSPEND:
2733         case FUNCTIONFS_SETUP:
2734                 rem_type1 = type;
2735                 /* Discard all similar events */
2736                 break;
2737
2738         case FUNCTIONFS_BIND:
2739         case FUNCTIONFS_UNBIND:
2740         case FUNCTIONFS_DISABLE:
2741         case FUNCTIONFS_ENABLE:
2742                 /* Discard everything other then power management. */
2743                 rem_type1 = FUNCTIONFS_SUSPEND;
2744                 rem_type2 = FUNCTIONFS_RESUME;
2745                 neg = 1;
2746                 break;
2747
2748         default:
2749                 WARN(1, "%d: unknown event, this should not happen\n", type);
2750                 return;
2751         }
2752
2753         {
2754                 u8 *ev  = ffs->ev.types, *out = ev;
2755                 unsigned n = ffs->ev.count;
2756                 for (; n; --n, ++ev)
2757                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2758                                 *out++ = *ev;
2759                         else
2760                                 pr_vdebug("purging event %d\n", *ev);
2761                 ffs->ev.count = out - ffs->ev.types;
2762         }
2763
2764         pr_vdebug("adding event %d\n", type);
2765         ffs->ev.types[ffs->ev.count++] = type;
2766         wake_up_locked(&ffs->ev.waitq);
2767         if (ffs->ffs_eventfd)
2768                 eventfd_signal(ffs->ffs_eventfd, 1);
2769 }
2770
2771 static void ffs_event_add(struct ffs_data *ffs,
2772                           enum usb_functionfs_event_type type)
2773 {
2774         unsigned long flags;
2775         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2776         __ffs_event_add(ffs, type);
2777         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2778 }
2779
2780 /* Bind/unbind USB function hooks *******************************************/
2781
2782 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2783 {
2784         int i;
2785
2786         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2787                 if (ffs->eps_addrmap[i] == endpoint_address)
2788                         return i;
2789         return -ENOENT;
2790 }
2791
2792 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2793                                     struct usb_descriptor_header *desc,
2794                                     void *priv)
2795 {
2796         struct usb_endpoint_descriptor *ds = (void *)desc;
2797         struct ffs_function *func = priv;
2798         struct ffs_ep *ffs_ep;
2799         unsigned ep_desc_id;
2800         int idx;
2801         static const char *speed_names[] = { "full", "high", "super" };
2802
2803         if (type != FFS_DESCRIPTOR)
2804                 return 0;
2805
2806         /*
2807          * If ss_descriptors is not NULL, we are reading super speed
2808          * descriptors; if hs_descriptors is not NULL, we are reading high
2809          * speed descriptors; otherwise, we are reading full speed
2810          * descriptors.
2811          */
2812         if (func->function.ss_descriptors) {
2813                 ep_desc_id = 2;
2814                 func->function.ss_descriptors[(long)valuep] = desc;
2815         } else if (func->function.hs_descriptors) {
2816                 ep_desc_id = 1;
2817                 func->function.hs_descriptors[(long)valuep] = desc;
2818         } else {
2819                 ep_desc_id = 0;
2820                 func->function.fs_descriptors[(long)valuep]    = desc;
2821         }
2822
2823         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2824                 return 0;
2825
2826         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2827         if (idx < 0)
2828                 return idx;
2829
2830         ffs_ep = func->eps + idx;
2831
2832         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2833                 pr_err("two %sspeed descriptors for EP %d\n",
2834                           speed_names[ep_desc_id],
2835                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2836                 return -EINVAL;
2837         }
2838         ffs_ep->descs[ep_desc_id] = ds;
2839
2840         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2841         if (ffs_ep->ep) {
2842                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2843                 if (!ds->wMaxPacketSize)
2844                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2845         } else {
2846                 struct usb_request *req;
2847                 struct usb_ep *ep;
2848                 u8 bEndpointAddress;
2849                 u16 wMaxPacketSize;
2850
2851                 /*
2852                  * We back up bEndpointAddress because autoconfig overwrites
2853                  * it with physical endpoint address.
2854                  */
2855                 bEndpointAddress = ds->bEndpointAddress;
2856                 /*
2857                  * We back up wMaxPacketSize because autoconfig treats
2858                  * endpoint descriptors as if they were full speed.
2859                  */
2860                 wMaxPacketSize = ds->wMaxPacketSize;
2861                 pr_vdebug("autoconfig\n");
2862                 ep = usb_ep_autoconfig(func->gadget, ds);
2863                 if (unlikely(!ep))
2864                         return -ENOTSUPP;
2865                 ep->driver_data = func->eps + idx;
2866
2867                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2868                 if (unlikely(!req))
2869                         return -ENOMEM;
2870
2871                 ffs_ep->ep  = ep;
2872                 ffs_ep->req = req;
2873                 func->eps_revmap[ds->bEndpointAddress &
2874                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2875                 /*
2876                  * If we use virtual address mapping, we restore
2877                  * original bEndpointAddress value.
2878                  */
2879                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2880                         ds->bEndpointAddress = bEndpointAddress;
2881                 /*
2882                  * Restore wMaxPacketSize which was potentially
2883                  * overwritten by autoconfig.
2884                  */
2885                 ds->wMaxPacketSize = wMaxPacketSize;
2886         }
2887         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2888
2889         return 0;
2890 }
2891
2892 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2893                                    struct usb_descriptor_header *desc,
2894                                    void *priv)
2895 {
2896         struct ffs_function *func = priv;
2897         unsigned idx;
2898         u8 newValue;
2899
2900         switch (type) {
2901         default:
2902         case FFS_DESCRIPTOR:
2903                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2904                 return 0;
2905
2906         case FFS_INTERFACE:
2907                 idx = *valuep;
2908                 if (func->interfaces_nums[idx] < 0) {
2909                         int id = usb_interface_id(func->conf, &func->function);
2910                         if (unlikely(id < 0))
2911                                 return id;
2912                         func->interfaces_nums[idx] = id;
2913                 }
2914                 newValue = func->interfaces_nums[idx];
2915                 break;
2916
2917         case FFS_STRING:
2918                 /* String' IDs are allocated when fsf_data is bound to cdev */
2919                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2920                 break;
2921
2922         case FFS_ENDPOINT:
2923                 /*
2924                  * USB_DT_ENDPOINT are handled in
2925                  * __ffs_func_bind_do_descs().
2926                  */
2927                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2928                         return 0;
2929
2930                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2931                 if (unlikely(!func->eps[idx].ep))
2932                         return -EINVAL;
2933
2934                 {
2935                         struct usb_endpoint_descriptor **descs;
2936                         descs = func->eps[idx].descs;
2937                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2938                 }
2939                 break;
2940         }
2941
2942         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2943         *valuep = newValue;
2944         return 0;
2945 }
2946
2947 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2948                                       struct usb_os_desc_header *h, void *data,
2949                                       unsigned len, void *priv)
2950 {
2951         struct ffs_function *func = priv;
2952         u8 length = 0;
2953
2954         switch (type) {
2955         case FFS_OS_DESC_EXT_COMPAT: {
2956                 struct usb_ext_compat_desc *desc = data;
2957                 struct usb_os_desc_table *t;
2958
2959                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2960                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2961                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2962                        ARRAY_SIZE(desc->CompatibleID) +
2963                        ARRAY_SIZE(desc->SubCompatibleID));
2964                 length = sizeof(*desc);
2965         }
2966                 break;
2967         case FFS_OS_DESC_EXT_PROP: {
2968                 struct usb_ext_prop_desc *desc = data;
2969                 struct usb_os_desc_table *t;
2970                 struct usb_os_desc_ext_prop *ext_prop;
2971                 char *ext_prop_name;
2972                 char *ext_prop_data;
2973
2974                 t = &func->function.os_desc_table[h->interface];
2975                 t->if_id = func->interfaces_nums[h->interface];
2976
2977                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2978                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2979
2980                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2981                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2982                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2983                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2984                 length = ext_prop->name_len + ext_prop->data_len + 14;
2985
2986                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2987                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2988                         ext_prop->name_len;
2989
2990                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2991                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2992                         ext_prop->data_len;
2993                 memcpy(ext_prop_data,
2994                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2995                        ext_prop->data_len);
2996                 /* unicode data reported to the host as "WCHAR"s */
2997                 switch (ext_prop->type) {
2998                 case USB_EXT_PROP_UNICODE:
2999                 case USB_EXT_PROP_UNICODE_ENV:
3000                 case USB_EXT_PROP_UNICODE_LINK:
3001                 case USB_EXT_PROP_UNICODE_MULTI:
3002                         ext_prop->data_len *= 2;
3003                         break;
3004                 }
3005                 ext_prop->data = ext_prop_data;
3006
3007                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3008                        ext_prop->name_len);
3009                 /* property name reported to the host as "WCHAR"s */
3010                 ext_prop->name_len *= 2;
3011                 ext_prop->name = ext_prop_name;
3012
3013                 t->os_desc->ext_prop_len +=
3014                         ext_prop->name_len + ext_prop->data_len + 14;
3015                 ++t->os_desc->ext_prop_count;
3016                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3017         }
3018                 break;
3019         default:
3020                 pr_vdebug("unknown descriptor: %d\n", type);
3021         }
3022
3023         return length;
3024 }
3025
3026 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3027                                                 struct usb_configuration *c)
3028 {
3029         struct ffs_function *func = ffs_func_from_usb(f);
3030         struct f_fs_opts *ffs_opts =
3031                 container_of(f->fi, struct f_fs_opts, func_inst);
3032         int ret;
3033
3034         ENTER();
3035
3036         /*
3037          * Legacy gadget triggers binding in functionfs_ready_callback,
3038          * which already uses locking; taking the same lock here would
3039          * cause a deadlock.
3040          *
3041          * Configfs-enabled gadgets however do need ffs_dev_lock.
3042          */
3043         if (!ffs_opts->no_configfs)
3044                 ffs_dev_lock();
3045         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3046         func->ffs = ffs_opts->dev->ffs_data;
3047         if (!ffs_opts->no_configfs)
3048                 ffs_dev_unlock();
3049         if (ret)
3050                 return ERR_PTR(ret);
3051
3052         func->conf = c;
3053         func->gadget = c->cdev->gadget;
3054
3055         /*
3056          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3057          * configurations are bound in sequence with list_for_each_entry,
3058          * in each configuration its functions are bound in sequence
3059          * with list_for_each_entry, so we assume no race condition
3060          * with regard to ffs_opts->bound access
3061          */
3062         if (!ffs_opts->refcnt) {
3063                 ret = functionfs_bind(func->ffs, c->cdev);
3064                 if (ret)
3065                         return ERR_PTR(ret);
3066         }
3067         ffs_opts->refcnt++;
3068         func->function.strings = func->ffs->stringtabs;
3069
3070         return ffs_opts;
3071 }
3072
3073 static int _ffs_func_bind(struct usb_configuration *c,
3074                           struct usb_function *f)
3075 {
3076         struct ffs_function *func = ffs_func_from_usb(f);
3077         struct ffs_data *ffs = func->ffs;
3078
3079         const int full = !!func->ffs->fs_descs_count;
3080         const int high = !!func->ffs->hs_descs_count;
3081         const int super = !!func->ffs->ss_descs_count;
3082
3083         int fs_len, hs_len, ss_len, ret, i;
3084         struct ffs_ep *eps_ptr;
3085
3086         /* Make it a single chunk, less management later on */
3087         vla_group(d);
3088         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3089         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3090                 full ? ffs->fs_descs_count + 1 : 0);
3091         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3092                 high ? ffs->hs_descs_count + 1 : 0);
3093         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3094                 super ? ffs->ss_descs_count + 1 : 0);
3095         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3096         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3097                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3098         vla_item_with_sz(d, char[16], ext_compat,
3099                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3100         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3101                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3102         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3103                          ffs->ms_os_descs_ext_prop_count);
3104         vla_item_with_sz(d, char, ext_prop_name,
3105                          ffs->ms_os_descs_ext_prop_name_len);
3106         vla_item_with_sz(d, char, ext_prop_data,
3107                          ffs->ms_os_descs_ext_prop_data_len);
3108         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3109         char *vlabuf;
3110
3111         ENTER();
3112
3113         /* Has descriptors only for speeds gadget does not support */
3114         if (unlikely(!(full | high | super)))
3115                 return -ENOTSUPP;
3116
3117         /* Allocate a single chunk, less management later on */
3118         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3119         if (unlikely(!vlabuf))
3120                 return -ENOMEM;
3121
3122         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3123         ffs->ms_os_descs_ext_prop_name_avail =
3124                 vla_ptr(vlabuf, d, ext_prop_name);
3125         ffs->ms_os_descs_ext_prop_data_avail =
3126                 vla_ptr(vlabuf, d, ext_prop_data);
3127
3128         /* Copy descriptors  */
3129         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3130                ffs->raw_descs_length);
3131
3132         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3133         eps_ptr = vla_ptr(vlabuf, d, eps);
3134         for (i = 0; i < ffs->eps_count; i++)
3135                 eps_ptr[i].num = -1;
3136
3137         /* Save pointers
3138          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3139         */
3140         func->eps             = vla_ptr(vlabuf, d, eps);
3141         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3142
3143         /*
3144          * Go through all the endpoint descriptors and allocate
3145          * endpoints first, so that later we can rewrite the endpoint
3146          * numbers without worrying that it may be described later on.
3147          */
3148         if (likely(full)) {
3149                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3150                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3151                                       vla_ptr(vlabuf, d, raw_descs),
3152                                       d_raw_descs__sz,
3153                                       __ffs_func_bind_do_descs, func);
3154                 if (unlikely(fs_len < 0)) {
3155                         ret = fs_len;
3156                         goto error;
3157                 }
3158         } else {
3159                 fs_len = 0;
3160         }
3161
3162         if (likely(high)) {
3163                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3164                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3165                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3166                                       d_raw_descs__sz - fs_len,
3167                                       __ffs_func_bind_do_descs, func);
3168                 if (unlikely(hs_len < 0)) {
3169                         ret = hs_len;
3170                         goto error;
3171                 }
3172         } else {
3173                 hs_len = 0;
3174         }
3175
3176         if (likely(super)) {
3177                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3178                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3179                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3180                                 d_raw_descs__sz - fs_len - hs_len,
3181                                 __ffs_func_bind_do_descs, func);
3182                 if (unlikely(ss_len < 0)) {
3183                         ret = ss_len;
3184                         goto error;
3185                 }
3186         } else {
3187                 ss_len = 0;
3188         }
3189
3190         /*
3191          * Now handle interface numbers allocation and interface and
3192          * endpoint numbers rewriting.  We can do that in one go
3193          * now.
3194          */
3195         ret = ffs_do_descs(ffs->fs_descs_count +
3196                            (high ? ffs->hs_descs_count : 0) +
3197                            (super ? ffs->ss_descs_count : 0),
3198                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3199                            __ffs_func_bind_do_nums, func);
3200         if (unlikely(ret < 0))
3201                 goto error;
3202
3203         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3204         if (c->cdev->use_os_string) {
3205                 for (i = 0; i < ffs->interfaces_count; ++i) {
3206                         struct usb_os_desc *desc;
3207
3208                         desc = func->function.os_desc_table[i].os_desc =
3209                                 vla_ptr(vlabuf, d, os_desc) +
3210                                 i * sizeof(struct usb_os_desc);
3211                         desc->ext_compat_id =
3212                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3213                         INIT_LIST_HEAD(&desc->ext_prop);
3214                 }
3215                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3216                                       vla_ptr(vlabuf, d, raw_descs) +
3217                                       fs_len + hs_len + ss_len,
3218                                       d_raw_descs__sz - fs_len - hs_len -
3219                                       ss_len,
3220                                       __ffs_func_bind_do_os_desc, func);
3221                 if (unlikely(ret < 0))
3222                         goto error;
3223         }
3224         func->function.os_desc_n =
3225                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3226
3227         /* And we're done */
3228         ffs_event_add(ffs, FUNCTIONFS_BIND);
3229         return 0;
3230
3231 error:
3232         /* XXX Do we need to release all claimed endpoints here? */
3233         return ret;
3234 }
3235
3236 static int ffs_func_bind(struct usb_configuration *c,
3237                          struct usb_function *f)
3238 {
3239         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3240         struct ffs_function *func = ffs_func_from_usb(f);
3241         int ret;
3242
3243         if (IS_ERR(ffs_opts))
3244                 return PTR_ERR(ffs_opts);
3245
3246         ret = _ffs_func_bind(c, f);
3247         if (ret && !--ffs_opts->refcnt)
3248                 functionfs_unbind(func->ffs);
3249
3250         return ret;
3251 }
3252
3253
3254 /* Other USB function hooks *************************************************/
3255
3256 static void ffs_reset_work(struct work_struct *work)
3257 {
3258         struct ffs_data *ffs = container_of(work,
3259                 struct ffs_data, reset_work);
3260         ffs_data_reset(ffs);
3261 }
3262
3263 static int ffs_func_set_alt(struct usb_function *f,
3264                             unsigned interface, unsigned alt)
3265 {
3266         struct ffs_function *func = ffs_func_from_usb(f);
3267         struct ffs_data *ffs = func->ffs;
3268         int ret = 0, intf;
3269
3270         if (alt != (unsigned)-1) {
3271                 intf = ffs_func_revmap_intf(func, interface);
3272                 if (unlikely(intf < 0))
3273                         return intf;
3274         }
3275
3276         if (ffs->func)
3277                 ffs_func_eps_disable(ffs->func);
3278
3279         if (ffs->state == FFS_DEACTIVATED) {
3280                 ffs->state = FFS_CLOSING;
3281                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3282                 schedule_work(&ffs->reset_work);
3283                 return -ENODEV;
3284         }
3285
3286         if (ffs->state != FFS_ACTIVE)
3287                 return -ENODEV;
3288
3289         if (alt == (unsigned)-1) {
3290                 ffs->func = NULL;
3291                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3292                 return 0;
3293         }
3294
3295         ffs->func = func;
3296         ret = ffs_func_eps_enable(func);
3297         if (likely(ret >= 0))
3298                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3299         return ret;
3300 }
3301
3302 static void ffs_func_disable(struct usb_function *f)
3303 {
3304         ffs_func_set_alt(f, 0, (unsigned)-1);
3305 }
3306
3307 static int ffs_func_setup(struct usb_function *f,
3308                           const struct usb_ctrlrequest *creq)
3309 {
3310         struct ffs_function *func = ffs_func_from_usb(f);
3311         struct ffs_data *ffs = func->ffs;
3312         unsigned long flags;
3313         int ret;
3314
3315         ENTER();
3316
3317         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3318         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3319         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3320         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3321         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3322
3323         /*
3324          * Most requests directed to interface go through here
3325          * (notable exceptions are set/get interface) so we need to
3326          * handle them.  All other either handled by composite or
3327          * passed to usb_configuration->setup() (if one is set).  No
3328          * matter, we will handle requests directed to endpoint here
3329          * as well (as it's straightforward).  Other request recipient
3330          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3331          * is being used.
3332          */
3333         if (ffs->state != FFS_ACTIVE)
3334                 return -ENODEV;
3335
3336         switch (creq->bRequestType & USB_RECIP_MASK) {
3337         case USB_RECIP_INTERFACE:
3338                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3339                 if (unlikely(ret < 0))
3340                         return ret;
3341                 break;
3342
3343         case USB_RECIP_ENDPOINT:
3344                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3345                 if (unlikely(ret < 0))
3346                         return ret;
3347                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3348                         ret = func->ffs->eps_addrmap[ret];
3349                 break;
3350
3351         default:
3352                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3353                         ret = le16_to_cpu(creq->wIndex);
3354                 else
3355                         return -EOPNOTSUPP;
3356         }
3357
3358         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3359         ffs->ev.setup = *creq;
3360         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3361         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3362         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3363
3364         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3365 }
3366
3367 static bool ffs_func_req_match(struct usb_function *f,
3368                                const struct usb_ctrlrequest *creq,
3369                                bool config0)
3370 {
3371         struct ffs_function *func = ffs_func_from_usb(f);
3372
3373         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3374                 return false;
3375
3376         switch (creq->bRequestType & USB_RECIP_MASK) {
3377         case USB_RECIP_INTERFACE:
3378                 return (ffs_func_revmap_intf(func,
3379                                              le16_to_cpu(creq->wIndex)) >= 0);
3380         case USB_RECIP_ENDPOINT:
3381                 return (ffs_func_revmap_ep(func,
3382                                            le16_to_cpu(creq->wIndex)) >= 0);
3383         default:
3384                 return (bool) (func->ffs->user_flags &
3385                                FUNCTIONFS_ALL_CTRL_RECIP);
3386         }
3387 }
3388
3389 static void ffs_func_suspend(struct usb_function *f)
3390 {
3391         ENTER();
3392         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3393 }
3394
3395 static void ffs_func_resume(struct usb_function *f)
3396 {
3397         ENTER();
3398         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3399 }
3400
3401
3402 /* Endpoint and interface numbers reverse mapping ***************************/
3403
3404 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3405 {
3406         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3407         return num ? num : -EDOM;
3408 }
3409
3410 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3411 {
3412         short *nums = func->interfaces_nums;
3413         unsigned count = func->ffs->interfaces_count;
3414
3415         for (; count; --count, ++nums) {
3416                 if (*nums >= 0 && *nums == intf)
3417                         return nums - func->interfaces_nums;
3418         }
3419
3420         return -EDOM;
3421 }
3422
3423
3424 /* Devices management *******************************************************/
3425
3426 static LIST_HEAD(ffs_devices);
3427
3428 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3429 {
3430         struct ffs_dev *dev;
3431
3432         if (!name)
3433                 return NULL;
3434
3435         list_for_each_entry(dev, &ffs_devices, entry) {
3436                 if (strcmp(dev->name, name) == 0)
3437                         return dev;
3438         }
3439
3440         return NULL;
3441 }
3442
3443 /*
3444  * ffs_lock must be taken by the caller of this function
3445  */
3446 static struct ffs_dev *_ffs_get_single_dev(void)
3447 {
3448         struct ffs_dev *dev;
3449
3450         if (list_is_singular(&ffs_devices)) {
3451                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3452                 if (dev->single)
3453                         return dev;
3454         }
3455
3456         return NULL;
3457 }
3458
3459 /*
3460  * ffs_lock must be taken by the caller of this function
3461  */
3462 static struct ffs_dev *_ffs_find_dev(const char *name)
3463 {
3464         struct ffs_dev *dev;
3465
3466         dev = _ffs_get_single_dev();
3467         if (dev)
3468                 return dev;
3469
3470         return _ffs_do_find_dev(name);
3471 }
3472
3473 /* Configfs support *********************************************************/
3474
3475 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3476 {
3477         return container_of(to_config_group(item), struct f_fs_opts,
3478                             func_inst.group);
3479 }
3480
3481 static void ffs_attr_release(struct config_item *item)
3482 {
3483         struct f_fs_opts *opts = to_ffs_opts(item);
3484
3485         usb_put_function_instance(&opts->func_inst);
3486 }
3487
3488 static struct configfs_item_operations ffs_item_ops = {
3489         .release        = ffs_attr_release,
3490 };
3491
3492 static const struct config_item_type ffs_func_type = {
3493         .ct_item_ops    = &ffs_item_ops,
3494         .ct_owner       = THIS_MODULE,
3495 };
3496
3497
3498 /* Function registration interface ******************************************/
3499
3500 static void ffs_free_inst(struct usb_function_instance *f)
3501 {
3502         struct f_fs_opts *opts;
3503
3504         opts = to_f_fs_opts(f);
3505         ffs_dev_lock();
3506         _ffs_free_dev(opts->dev);
3507         ffs_dev_unlock();
3508         kfree(opts);
3509 }
3510
3511 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3512 {
3513         if (strlen(name) >= sizeof_field(struct ffs_dev, name))
3514                 return -ENAMETOOLONG;
3515         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3516 }
3517
3518 static struct usb_function_instance *ffs_alloc_inst(void)
3519 {
3520         struct f_fs_opts *opts;
3521         struct ffs_dev *dev;
3522
3523         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3524         if (!opts)
3525                 return ERR_PTR(-ENOMEM);
3526
3527         opts->func_inst.set_inst_name = ffs_set_inst_name;
3528         opts->func_inst.free_func_inst = ffs_free_inst;
3529         ffs_dev_lock();
3530         dev = _ffs_alloc_dev();
3531         ffs_dev_unlock();
3532         if (IS_ERR(dev)) {
3533                 kfree(opts);
3534                 return ERR_CAST(dev);
3535         }
3536         opts->dev = dev;
3537         dev->opts = opts;
3538
3539         config_group_init_type_name(&opts->func_inst.group, "",
3540                                     &ffs_func_type);
3541         return &opts->func_inst;
3542 }
3543
3544 static void ffs_free(struct usb_function *f)
3545 {
3546         kfree(ffs_func_from_usb(f));
3547 }
3548
3549 static void ffs_func_unbind(struct usb_configuration *c,
3550                             struct usb_function *f)
3551 {
3552         struct ffs_function *func = ffs_func_from_usb(f);
3553         struct ffs_data *ffs = func->ffs;
3554         struct f_fs_opts *opts =
3555                 container_of(f->fi, struct f_fs_opts, func_inst);
3556         struct ffs_ep *ep = func->eps;
3557         unsigned count = ffs->eps_count;
3558         unsigned long flags;
3559
3560         ENTER();
3561         if (ffs->func == func) {
3562                 ffs_func_eps_disable(func);
3563                 ffs->func = NULL;
3564         }
3565
3566         if (!--opts->refcnt)
3567                 functionfs_unbind(ffs);
3568
3569         /* cleanup after autoconfig */
3570         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3571         while (count--) {
3572                 if (ep->ep && ep->req)
3573                         usb_ep_free_request(ep->ep, ep->req);
3574                 ep->req = NULL;
3575                 ++ep;
3576         }
3577         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3578         kfree(func->eps);
3579         func->eps = NULL;
3580         /*
3581          * eps, descriptors and interfaces_nums are allocated in the
3582          * same chunk so only one free is required.
3583          */
3584         func->function.fs_descriptors = NULL;
3585         func->function.hs_descriptors = NULL;
3586         func->function.ss_descriptors = NULL;
3587         func->interfaces_nums = NULL;
3588
3589         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3590 }
3591
3592 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3593 {
3594         struct ffs_function *func;
3595
3596         ENTER();
3597
3598         func = kzalloc(sizeof(*func), GFP_KERNEL);
3599         if (unlikely(!func))
3600                 return ERR_PTR(-ENOMEM);
3601
3602         func->function.name    = "Function FS Gadget";
3603
3604         func->function.bind    = ffs_func_bind;
3605         func->function.unbind  = ffs_func_unbind;
3606         func->function.set_alt = ffs_func_set_alt;
3607         func->function.disable = ffs_func_disable;
3608         func->function.setup   = ffs_func_setup;
3609         func->function.req_match = ffs_func_req_match;
3610         func->function.suspend = ffs_func_suspend;
3611         func->function.resume  = ffs_func_resume;
3612         func->function.free_func = ffs_free;
3613
3614         return &func->function;
3615 }
3616
3617 /*
3618  * ffs_lock must be taken by the caller of this function
3619  */
3620 static struct ffs_dev *_ffs_alloc_dev(void)
3621 {
3622         struct ffs_dev *dev;
3623         int ret;
3624
3625         if (_ffs_get_single_dev())
3626                         return ERR_PTR(-EBUSY);
3627
3628         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3629         if (!dev)
3630                 return ERR_PTR(-ENOMEM);
3631
3632         if (list_empty(&ffs_devices)) {
3633                 ret = functionfs_init();
3634                 if (ret) {
3635                         kfree(dev);
3636                         return ERR_PTR(ret);
3637                 }
3638         }
3639
3640         list_add(&dev->entry, &ffs_devices);
3641
3642         return dev;
3643 }
3644
3645 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3646 {
3647         struct ffs_dev *existing;
3648         int ret = 0;
3649
3650         ffs_dev_lock();
3651
3652         existing = _ffs_do_find_dev(name);
3653         if (!existing)
3654                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3655         else if (existing != dev)
3656                 ret = -EBUSY;
3657
3658         ffs_dev_unlock();
3659
3660         return ret;
3661 }
3662 EXPORT_SYMBOL_GPL(ffs_name_dev);
3663
3664 int ffs_single_dev(struct ffs_dev *dev)
3665 {
3666         int ret;
3667
3668         ret = 0;
3669         ffs_dev_lock();
3670
3671         if (!list_is_singular(&ffs_devices))
3672                 ret = -EBUSY;
3673         else
3674                 dev->single = true;
3675
3676         ffs_dev_unlock();
3677         return ret;
3678 }
3679 EXPORT_SYMBOL_GPL(ffs_single_dev);
3680
3681 /*
3682  * ffs_lock must be taken by the caller of this function
3683  */
3684 static void _ffs_free_dev(struct ffs_dev *dev)
3685 {
3686         list_del(&dev->entry);
3687
3688         /* Clear the private_data pointer to stop incorrect dev access */
3689         if (dev->ffs_data)
3690                 dev->ffs_data->private_data = NULL;
3691
3692         kfree(dev);
3693         if (list_empty(&ffs_devices))
3694                 functionfs_cleanup();
3695 }
3696
3697 static void *ffs_acquire_dev(const char *dev_name)
3698 {
3699         struct ffs_dev *ffs_dev;
3700
3701         ENTER();
3702         ffs_dev_lock();
3703
3704         ffs_dev = _ffs_find_dev(dev_name);
3705         if (!ffs_dev)
3706                 ffs_dev = ERR_PTR(-ENOENT);
3707         else if (ffs_dev->mounted)
3708                 ffs_dev = ERR_PTR(-EBUSY);
3709         else if (ffs_dev->ffs_acquire_dev_callback &&
3710             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3711                 ffs_dev = ERR_PTR(-ENOENT);
3712         else
3713                 ffs_dev->mounted = true;
3714
3715         ffs_dev_unlock();
3716         return ffs_dev;
3717 }
3718
3719 static void ffs_release_dev(struct ffs_data *ffs_data)
3720 {
3721         struct ffs_dev *ffs_dev;
3722
3723         ENTER();
3724         ffs_dev_lock();
3725
3726         ffs_dev = ffs_data->private_data;
3727         if (ffs_dev) {
3728                 ffs_dev->mounted = false;
3729
3730                 if (ffs_dev->ffs_release_dev_callback)
3731                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3732         }
3733
3734         ffs_dev_unlock();
3735 }
3736
3737 static int ffs_ready(struct ffs_data *ffs)
3738 {
3739         struct ffs_dev *ffs_obj;
3740         int ret = 0;
3741
3742         ENTER();
3743         ffs_dev_lock();
3744
3745         ffs_obj = ffs->private_data;
3746         if (!ffs_obj) {
3747                 ret = -EINVAL;
3748                 goto done;
3749         }
3750         if (WARN_ON(ffs_obj->desc_ready)) {
3751                 ret = -EBUSY;
3752                 goto done;
3753         }
3754
3755         ffs_obj->desc_ready = true;
3756         ffs_obj->ffs_data = ffs;
3757
3758         if (ffs_obj->ffs_ready_callback) {
3759                 ret = ffs_obj->ffs_ready_callback(ffs);
3760                 if (ret)
3761                         goto done;
3762         }
3763
3764         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3765 done:
3766         ffs_dev_unlock();
3767         return ret;
3768 }
3769
3770 static void ffs_closed(struct ffs_data *ffs)
3771 {
3772         struct ffs_dev *ffs_obj;
3773         struct f_fs_opts *opts;
3774         struct config_item *ci;
3775
3776         ENTER();
3777         ffs_dev_lock();
3778
3779         ffs_obj = ffs->private_data;
3780         if (!ffs_obj)
3781                 goto done;
3782
3783         ffs_obj->desc_ready = false;
3784         ffs_obj->ffs_data = NULL;
3785
3786         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3787             ffs_obj->ffs_closed_callback)
3788                 ffs_obj->ffs_closed_callback(ffs);
3789
3790         if (ffs_obj->opts)
3791                 opts = ffs_obj->opts;
3792         else
3793                 goto done;
3794
3795         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3796             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3797                 goto done;
3798
3799         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3800         ffs_dev_unlock();
3801
3802         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3803                 unregister_gadget_item(ci);
3804         return;
3805 done:
3806         ffs_dev_unlock();
3807 }
3808
3809 /* Misc helper functions ****************************************************/
3810
3811 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3812 {
3813         return nonblock
3814                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3815                 : mutex_lock_interruptible(mutex);
3816 }
3817
3818 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3819 {
3820         char *data;
3821
3822         if (unlikely(!len))
3823                 return NULL;
3824
3825         data = kmalloc(len, GFP_KERNEL);
3826         if (unlikely(!data))
3827                 return ERR_PTR(-ENOMEM);
3828
3829         if (unlikely(copy_from_user(data, buf, len))) {
3830                 kfree(data);
3831                 return ERR_PTR(-EFAULT);
3832         }
3833
3834         pr_vdebug("Buffer from user space:\n");
3835         ffs_dump_mem("", data, len);
3836
3837         return data;
3838 }
3839
3840 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3841 MODULE_LICENSE("GPL");
3842 MODULE_AUTHOR("Michal Nazarewicz");