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 int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data);
 254 static void ffs_release_dev(struct ffs_dev *ffs_dev);
 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 (ret < 0)
 300                 return ret;
 301
 302         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 303         if (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 (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 (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 (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 (ret < 0)
 372                                 break;
 373
 374                         ret = ffs_epfiles_create(ffs);
 375                         if (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 (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 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 (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 (!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 (len) {
 571                         data = kmalloc(len, GFP_KERNEL);
 572                         if (!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 ((ret > 0) && (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 (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 (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 (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 (ret == data_len)
 722                 return ret;
 723
 724         if (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 (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 (data_len == ret)
 912                 return ret;
 913
 914         if (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 (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 (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 (!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 (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 (ret < 0)
1074                         goto error_lock;
1075
1076                 spin_unlock_irq(&epfile->ffs->eps_lock);
1077
1078                 if (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 (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 (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 (!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 (!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 desc1, *desc;
1330
1331                 switch (epfile->ffs->gadget->speed) {
1332                 case USB_SPEED_SUPER:
1333                 case USB_SPEED_SUPER_PLUS:
1334                         desc_idx = 2;
1335                         break;
1336                 case USB_SPEED_HIGH:
1337                         desc_idx = 1;
1338                         break;
1339                 default:
1340                         desc_idx = 0;
1341                 }
1342
1343                 desc = epfile->ep->descs[desc_idx];
1344                 memcpy(&desc1, desc, desc->bLength);
1345
1346                 spin_unlock_irq(&epfile->ffs->eps_lock);
1347                 ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
1348                 if (ret)
1349                         ret = -EFAULT;
1350                 return ret;
1351         }
1352         default:
1353                 ret = -ENOTTY;
1354         }
1355         spin_unlock_irq(&epfile->ffs->eps_lock);
1356
1357         return ret;
1358 }
1359
1360 static const struct file_operations ffs_epfile_operations = {
1361         .llseek =       no_llseek,
1362
1363         .open =         ffs_epfile_open,
1364         .write_iter =   ffs_epfile_write_iter,
1365         .read_iter =    ffs_epfile_read_iter,
1366         .release =      ffs_epfile_release,
1367         .unlocked_ioctl =       ffs_epfile_ioctl,
1368         .compat_ioctl = compat_ptr_ioctl,
1369 };
1370
1371
1372 /* File system and super block operations ***********************************/
1373
1374 /*
1375  * Mounting the file system creates a controller file, used first for
1376  * function configuration then later for event monitoring.
1377  */
1378
1379 static struct inode *__must_check
1380 ffs_sb_make_inode(struct super_block *sb, void *data,
1381                   const struct file_operations *fops,
1382                   const struct inode_operations *iops,
1383                   struct ffs_file_perms *perms)
1384 {
1385         struct inode *inode;
1386
1387         ENTER();
1388
1389         inode = new_inode(sb);
1390
1391         if (inode) {
1392                 struct timespec64 ts = current_time(inode);
1393
1394                 inode->i_ino     = get_next_ino();
1395                 inode->i_mode    = perms->mode;
1396                 inode->i_uid     = perms->uid;
1397                 inode->i_gid     = perms->gid;
1398                 inode->i_atime   = ts;
1399                 inode->i_mtime   = ts;
1400                 inode->i_ctime   = ts;
1401                 inode->i_private = data;
1402                 if (fops)
1403                         inode->i_fop = fops;
1404                 if (iops)
1405                         inode->i_op  = iops;
1406         }
1407
1408         return inode;
1409 }
1410
1411 /* Create "regular" file */
1412 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1413                                         const char *name, void *data,
1414                                         const struct file_operations *fops)
1415 {
1416         struct ffs_data *ffs = sb->s_fs_info;
1417         struct dentry   *dentry;
1418         struct inode    *inode;
1419
1420         ENTER();
1421
1422         dentry = d_alloc_name(sb->s_root, name);
1423         if (!dentry)
1424                 return NULL;
1425
1426         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1427         if (!inode) {
1428                 dput(dentry);
1429                 return NULL;
1430         }
1431
1432         d_add(dentry, inode);
1433         return dentry;
1434 }
1435
1436 /* Super block */
1437 static const struct super_operations ffs_sb_operations = {
1438         .statfs =       simple_statfs,
1439         .drop_inode =   generic_delete_inode,
1440 };
1441
1442 struct ffs_sb_fill_data {
1443         struct ffs_file_perms perms;
1444         umode_t root_mode;
1445         const char *dev_name;
1446         bool no_disconnect;
1447         struct ffs_data *ffs_data;
1448 };
1449
1450 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1451 {
1452         struct ffs_sb_fill_data *data = fc->fs_private;
1453         struct inode    *inode;
1454         struct ffs_data *ffs = data->ffs_data;
1455
1456         ENTER();
1457
1458         ffs->sb              = sb;
1459         data->ffs_data       = NULL;
1460         sb->s_fs_info        = ffs;
1461         sb->s_blocksize      = PAGE_SIZE;
1462         sb->s_blocksize_bits = PAGE_SHIFT;
1463         sb->s_magic          = FUNCTIONFS_MAGIC;
1464         sb->s_op             = &ffs_sb_operations;
1465         sb->s_time_gran      = 1;
1466
1467         /* Root inode */
1468         data->perms.mode = data->root_mode;
1469         inode = ffs_sb_make_inode(sb, NULL,
1470                                   &simple_dir_operations,
1471                                   &simple_dir_inode_operations,
1472                                   &data->perms);
1473         sb->s_root = d_make_root(inode);
1474         if (!sb->s_root)
1475                 return -ENOMEM;
1476
1477         /* EP0 file */
1478         if (!ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations))
1479                 return -ENOMEM;
1480
1481         return 0;
1482 }
1483
1484 enum {
1485         Opt_no_disconnect,
1486         Opt_rmode,
1487         Opt_fmode,
1488         Opt_mode,
1489         Opt_uid,
1490         Opt_gid,
1491 };
1492
1493 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1494         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1495         fsparam_u32     ("rmode",               Opt_rmode),
1496         fsparam_u32     ("fmode",               Opt_fmode),
1497         fsparam_u32     ("mode",                Opt_mode),
1498         fsparam_u32     ("uid",                 Opt_uid),
1499         fsparam_u32     ("gid",                 Opt_gid),
1500         {}
1501 };
1502
1503 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1504 {
1505         struct ffs_sb_fill_data *data = fc->fs_private;
1506         struct fs_parse_result result;
1507         int opt;
1508
1509         ENTER();
1510
1511         opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1512         if (opt < 0)
1513                 return opt;
1514
1515         switch (opt) {
1516         case Opt_no_disconnect:
1517                 data->no_disconnect = result.boolean;
1518                 break;
1519         case Opt_rmode:
1520                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1521                 break;
1522         case Opt_fmode:
1523                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1524                 break;
1525         case Opt_mode:
1526                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1527                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1528                 break;
1529
1530         case Opt_uid:
1531                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1532                 if (!uid_valid(data->perms.uid))
1533                         goto unmapped_value;
1534                 break;
1535         case Opt_gid:
1536                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1537                 if (!gid_valid(data->perms.gid))
1538                         goto unmapped_value;
1539                 break;
1540
1541         default:
1542                 return -ENOPARAM;
1543         }
1544
1545         return 0;
1546
1547 unmapped_value:
1548         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1549 }
1550
1551 /*
1552  * Set up the superblock for a mount.
1553  */
1554 static int ffs_fs_get_tree(struct fs_context *fc)
1555 {
1556         struct ffs_sb_fill_data *ctx = fc->fs_private;
1557         struct ffs_data *ffs;
1558         int ret;
1559
1560         ENTER();
1561
1562         if (!fc->source)
1563                 return invalf(fc, "No source specified");
1564
1565         ffs = ffs_data_new(fc->source);
1566         if (!ffs)
1567                 return -ENOMEM;
1568         ffs->file_perms = ctx->perms;
1569         ffs->no_disconnect = ctx->no_disconnect;
1570
1571         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1572         if (!ffs->dev_name) {
1573                 ffs_data_put(ffs);
1574                 return -ENOMEM;
1575         }
1576
1577         ret = ffs_acquire_dev(ffs->dev_name, ffs);
1578         if (ret) {
1579                 ffs_data_put(ffs);
1580                 return ret;
1581         }
1582
1583         ctx->ffs_data = ffs;
1584         return get_tree_nodev(fc, ffs_sb_fill);
1585 }
1586
1587 static void ffs_fs_free_fc(struct fs_context *fc)
1588 {
1589         struct ffs_sb_fill_data *ctx = fc->fs_private;
1590
1591         if (ctx) {
1592                 if (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_data_closed(sb->s_fs_info);
1633 }
1634
1635 static struct file_system_type ffs_fs_type = {
1636         .owner          = THIS_MODULE,
1637         .name           = "functionfs",
1638         .init_fs_context = ffs_fs_init_fs_context,
1639         .parameters     = ffs_fs_fs_parameters,
1640         .kill_sb        = ffs_fs_kill_sb,
1641 };
1642 MODULE_ALIAS_FS("functionfs");
1643
1644
1645 /* Driver's main init/cleanup functions *************************************/
1646
1647 static int functionfs_init(void)
1648 {
1649         int ret;
1650
1651         ENTER();
1652
1653         ret = register_filesystem(&ffs_fs_type);
1654         if (!ret)
1655                 pr_info("file system registered\n");
1656         else
1657                 pr_err("failed registering file system (%d)\n", ret);
1658
1659         return ret;
1660 }
1661
1662 static void functionfs_cleanup(void)
1663 {
1664         ENTER();
1665
1666         pr_info("unloading\n");
1667         unregister_filesystem(&ffs_fs_type);
1668 }
1669
1670
1671 /* ffs_data and ffs_function construction and destruction code **************/
1672
1673 static void ffs_data_clear(struct ffs_data *ffs);
1674 static void ffs_data_reset(struct ffs_data *ffs);
1675
1676 static void ffs_data_get(struct ffs_data *ffs)
1677 {
1678         ENTER();
1679
1680         refcount_inc(&ffs->ref);
1681 }
1682
1683 static void ffs_data_opened(struct ffs_data *ffs)
1684 {
1685         ENTER();
1686
1687         refcount_inc(&ffs->ref);
1688         if (atomic_add_return(1, &ffs->opened) == 1 &&
1689                         ffs->state == FFS_DEACTIVATED) {
1690                 ffs->state = FFS_CLOSING;
1691                 ffs_data_reset(ffs);
1692         }
1693 }
1694
1695 static void ffs_data_put(struct ffs_data *ffs)
1696 {
1697         ENTER();
1698
1699         if (refcount_dec_and_test(&ffs->ref)) {
1700                 pr_info("%s(): freeing\n", __func__);
1701                 ffs_data_clear(ffs);
1702                 ffs_release_dev(ffs->private_data);
1703                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1704                        swait_active(&ffs->ep0req_completion.wait) ||
1705                        waitqueue_active(&ffs->wait));
1706                 destroy_workqueue(ffs->io_completion_wq);
1707                 kfree(ffs->dev_name);
1708                 kfree(ffs);
1709         }
1710 }
1711
1712 static void ffs_data_closed(struct ffs_data *ffs)
1713 {
1714         ENTER();
1715
1716         if (atomic_dec_and_test(&ffs->opened)) {
1717                 if (ffs->no_disconnect) {
1718                         ffs->state = FFS_DEACTIVATED;
1719                         if (ffs->epfiles) {
1720                                 ffs_epfiles_destroy(ffs->epfiles,
1721                                                    ffs->eps_count);
1722                                 ffs->epfiles = NULL;
1723                         }
1724                         if (ffs->setup_state == FFS_SETUP_PENDING)
1725                                 __ffs_ep0_stall(ffs);
1726                 } else {
1727                         ffs->state = FFS_CLOSING;
1728                         ffs_data_reset(ffs);
1729                 }
1730         }
1731         if (atomic_read(&ffs->opened) < 0) {
1732                 ffs->state = FFS_CLOSING;
1733                 ffs_data_reset(ffs);
1734         }
1735
1736         ffs_data_put(ffs);
1737 }
1738
1739 static struct ffs_data *ffs_data_new(const char *dev_name)
1740 {
1741         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1742         if (!ffs)
1743                 return NULL;
1744
1745         ENTER();
1746
1747         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1748         if (!ffs->io_completion_wq) {
1749                 kfree(ffs);
1750                 return NULL;
1751         }
1752
1753         refcount_set(&ffs->ref, 1);
1754         atomic_set(&ffs->opened, 0);
1755         ffs->state = FFS_READ_DESCRIPTORS;
1756         mutex_init(&ffs->mutex);
1757         spin_lock_init(&ffs->eps_lock);
1758         init_waitqueue_head(&ffs->ev.waitq);
1759         init_waitqueue_head(&ffs->wait);
1760         init_completion(&ffs->ep0req_completion);
1761
1762         /* XXX REVISIT need to update it in some places, or do we? */
1763         ffs->ev.can_stall = 1;
1764
1765         return ffs;
1766 }
1767
1768 static void ffs_data_clear(struct ffs_data *ffs)
1769 {
1770         ENTER();
1771
1772         ffs_closed(ffs);
1773
1774         BUG_ON(ffs->gadget);
1775
1776         if (ffs->epfiles)
1777                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1778
1779         if (ffs->ffs_eventfd)
1780                 eventfd_ctx_put(ffs->ffs_eventfd);
1781
1782         kfree(ffs->raw_descs_data);
1783         kfree(ffs->raw_strings);
1784         kfree(ffs->stringtabs);
1785 }
1786
1787 static void ffs_data_reset(struct ffs_data *ffs)
1788 {
1789         ENTER();
1790
1791         ffs_data_clear(ffs);
1792
1793         ffs->epfiles = NULL;
1794         ffs->raw_descs_data = NULL;
1795         ffs->raw_descs = NULL;
1796         ffs->raw_strings = NULL;
1797         ffs->stringtabs = NULL;
1798
1799         ffs->raw_descs_length = 0;
1800         ffs->fs_descs_count = 0;
1801         ffs->hs_descs_count = 0;
1802         ffs->ss_descs_count = 0;
1803
1804         ffs->strings_count = 0;
1805         ffs->interfaces_count = 0;
1806         ffs->eps_count = 0;
1807
1808         ffs->ev.count = 0;
1809
1810         ffs->state = FFS_READ_DESCRIPTORS;
1811         ffs->setup_state = FFS_NO_SETUP;
1812         ffs->flags = 0;
1813
1814         ffs->ms_os_descs_ext_prop_count = 0;
1815         ffs->ms_os_descs_ext_prop_name_len = 0;
1816         ffs->ms_os_descs_ext_prop_data_len = 0;
1817 }
1818
1819
1820 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1821 {
1822         struct usb_gadget_strings **lang;
1823         int first_id;
1824
1825         ENTER();
1826
1827         if (WARN_ON(ffs->state != FFS_ACTIVE
1828                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1829                 return -EBADFD;
1830
1831         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1832         if (first_id < 0)
1833                 return first_id;
1834
1835         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1836         if (!ffs->ep0req)
1837                 return -ENOMEM;
1838         ffs->ep0req->complete = ffs_ep0_complete;
1839         ffs->ep0req->context = ffs;
1840
1841         lang = ffs->stringtabs;
1842         if (lang) {
1843                 for (; *lang; ++lang) {
1844                         struct usb_string *str = (*lang)->strings;
1845                         int id = first_id;
1846                         for (; str->s; ++id, ++str)
1847                                 str->id = id;
1848                 }
1849         }
1850
1851         ffs->gadget = cdev->gadget;
1852         ffs_data_get(ffs);
1853         return 0;
1854 }
1855
1856 static void functionfs_unbind(struct ffs_data *ffs)
1857 {
1858         ENTER();
1859
1860         if (!WARN_ON(!ffs->gadget)) {
1861                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1862                 ffs->ep0req = NULL;
1863                 ffs->gadget = NULL;
1864                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1865                 ffs_data_put(ffs);
1866         }
1867 }
1868
1869 static int ffs_epfiles_create(struct ffs_data *ffs)
1870 {
1871         struct ffs_epfile *epfile, *epfiles;
1872         unsigned i, count;
1873
1874         ENTER();
1875
1876         count = ffs->eps_count;
1877         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1878         if (!epfiles)
1879                 return -ENOMEM;
1880
1881         epfile = epfiles;
1882         for (i = 1; i <= count; ++i, ++epfile) {
1883                 epfile->ffs = ffs;
1884                 mutex_init(&epfile->mutex);
1885                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1886                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1887                 else
1888                         sprintf(epfile->name, "ep%u", i);
1889                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1890                                                  epfile,
1891                                                  &ffs_epfile_operations);
1892                 if (!epfile->dentry) {
1893                         ffs_epfiles_destroy(epfiles, i - 1);
1894                         return -ENOMEM;
1895                 }
1896         }
1897
1898         ffs->epfiles = epfiles;
1899         return 0;
1900 }
1901
1902 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1903 {
1904         struct ffs_epfile *epfile = epfiles;
1905
1906         ENTER();
1907
1908         for (; count; --count, ++epfile) {
1909                 BUG_ON(mutex_is_locked(&epfile->mutex));
1910                 if (epfile->dentry) {
1911                         d_delete(epfile->dentry);
1912                         dput(epfile->dentry);
1913                         epfile->dentry = NULL;
1914                 }
1915         }
1916
1917         kfree(epfiles);
1918 }
1919
1920 static void ffs_func_eps_disable(struct ffs_function *func)
1921 {
1922         struct ffs_ep *ep         = func->eps;
1923         struct ffs_epfile *epfile = func->ffs->epfiles;
1924         unsigned count            = func->ffs->eps_count;
1925         unsigned long flags;
1926
1927         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1928         while (count--) {
1929                 /* pending requests get nuked */
1930                 if (ep->ep)
1931                         usb_ep_disable(ep->ep);
1932                 ++ep;
1933
1934                 if (epfile) {
1935                         epfile->ep = NULL;
1936                         __ffs_epfile_read_buffer_free(epfile);
1937                         ++epfile;
1938                 }
1939         }
1940         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1941 }
1942
1943 static int ffs_func_eps_enable(struct ffs_function *func)
1944 {
1945         struct ffs_data *ffs      = func->ffs;
1946         struct ffs_ep *ep         = func->eps;
1947         struct ffs_epfile *epfile = ffs->epfiles;
1948         unsigned count            = ffs->eps_count;
1949         unsigned long flags;
1950         int ret = 0;
1951
1952         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1953         while(count--) {
1954                 ep->ep->driver_data = ep;
1955
1956                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1957                 if (ret) {
1958                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1959                                         __func__, ep->ep->name, ret);
1960                         break;
1961                 }
1962
1963                 ret = usb_ep_enable(ep->ep);
1964                 if (!ret) {
1965                         epfile->ep = ep;
1966                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1967                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1968                 } else {
1969                         break;
1970                 }
1971
1972                 ++ep;
1973                 ++epfile;
1974         }
1975
1976         wake_up_interruptible(&ffs->wait);
1977         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1978
1979         return ret;
1980 }
1981
1982
1983 /* Parsing and building descriptors and strings *****************************/
1984
1985 /*
1986  * This validates if data pointed by data is a valid USB descriptor as
1987  * well as record how many interfaces, endpoints and strings are
1988  * required by given configuration.  Returns address after the
1989  * descriptor or NULL if data is invalid.
1990  */
1991
1992 enum ffs_entity_type {
1993         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1994 };
1995
1996 enum ffs_os_desc_type {
1997         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1998 };
1999
2000 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2001                                    u8 *valuep,
2002                                    struct usb_descriptor_header *desc,
2003                                    void *priv);
2004
2005 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2006                                     struct usb_os_desc_header *h, void *data,
2007                                     unsigned len, void *priv);
2008
2009 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2010                                            ffs_entity_callback entity,
2011                                            void *priv, int *current_class)
2012 {
2013         struct usb_descriptor_header *_ds = (void *)data;
2014         u8 length;
2015         int ret;
2016
2017         ENTER();
2018
2019         /* At least two bytes are required: length and type */
2020         if (len < 2) {
2021                 pr_vdebug("descriptor too short\n");
2022                 return -EINVAL;
2023         }
2024
2025         /* If we have at least as many bytes as the descriptor takes? */
2026         length = _ds->bLength;
2027         if (len < length) {
2028                 pr_vdebug("descriptor longer then available data\n");
2029                 return -EINVAL;
2030         }
2031
2032 #define __entity_check_INTERFACE(val)  1
2033 #define __entity_check_STRING(val)     (val)
2034 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2035 #define __entity(type, val) do {                                        \
2036                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2037                 if (!__entity_check_ ##type(val)) {                     \
2038                         pr_vdebug("invalid entity's value\n");          \
2039                         return -EINVAL;                                 \
2040                 }                                                       \
2041                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2042                 if (ret < 0) {                                          \
2043                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2044                                  (val), ret);                           \
2045                         return ret;                                     \
2046                 }                                                       \
2047         } while (0)
2048
2049         /* Parse descriptor depending on type. */
2050         switch (_ds->bDescriptorType) {
2051         case USB_DT_DEVICE:
2052         case USB_DT_CONFIG:
2053         case USB_DT_STRING:
2054         case USB_DT_DEVICE_QUALIFIER:
2055                 /* function can't have any of those */
2056                 pr_vdebug("descriptor reserved for gadget: %d\n",
2057                       _ds->bDescriptorType);
2058                 return -EINVAL;
2059
2060         case USB_DT_INTERFACE: {
2061                 struct usb_interface_descriptor *ds = (void *)_ds;
2062                 pr_vdebug("interface descriptor\n");
2063                 if (length != sizeof *ds)
2064                         goto inv_length;
2065
2066                 __entity(INTERFACE, ds->bInterfaceNumber);
2067                 if (ds->iInterface)
2068                         __entity(STRING, ds->iInterface);
2069                 *current_class = ds->bInterfaceClass;
2070         }
2071                 break;
2072
2073         case USB_DT_ENDPOINT: {
2074                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2075                 pr_vdebug("endpoint descriptor\n");
2076                 if (length != USB_DT_ENDPOINT_SIZE &&
2077                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2078                         goto inv_length;
2079                 __entity(ENDPOINT, ds->bEndpointAddress);
2080         }
2081                 break;
2082
2083         case USB_TYPE_CLASS | 0x01:
2084                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2085                         pr_vdebug("hid descriptor\n");
2086                         if (length != sizeof(struct hid_descriptor))
2087                                 goto inv_length;
2088                         break;
2089                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2090                         pr_vdebug("ccid descriptor\n");
2091                         if (length != sizeof(struct ccid_descriptor))
2092                                 goto inv_length;
2093                         break;
2094                 } else {
2095                         pr_vdebug("unknown descriptor: %d for class %d\n",
2096                               _ds->bDescriptorType, *current_class);
2097                         return -EINVAL;
2098                 }
2099
2100         case USB_DT_OTG:
2101                 if (length != sizeof(struct usb_otg_descriptor))
2102                         goto inv_length;
2103                 break;
2104
2105         case USB_DT_INTERFACE_ASSOCIATION: {
2106                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2107                 pr_vdebug("interface association descriptor\n");
2108                 if (length != sizeof *ds)
2109                         goto inv_length;
2110                 if (ds->iFunction)
2111                         __entity(STRING, ds->iFunction);
2112         }
2113                 break;
2114
2115         case USB_DT_SS_ENDPOINT_COMP:
2116                 pr_vdebug("EP SS companion descriptor\n");
2117                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2118                         goto inv_length;
2119                 break;
2120
2121         case USB_DT_OTHER_SPEED_CONFIG:
2122         case USB_DT_INTERFACE_POWER:
2123         case USB_DT_DEBUG:
2124         case USB_DT_SECURITY:
2125         case USB_DT_CS_RADIO_CONTROL:
2126                 /* TODO */
2127                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2128                 return -EINVAL;
2129
2130         default:
2131                 /* We should never be here */
2132                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2133                 return -EINVAL;
2134
2135 inv_length:
2136                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2137                           _ds->bLength, _ds->bDescriptorType);
2138                 return -EINVAL;
2139         }
2140
2141 #undef __entity
2142 #undef __entity_check_DESCRIPTOR
2143 #undef __entity_check_INTERFACE
2144 #undef __entity_check_STRING
2145 #undef __entity_check_ENDPOINT
2146
2147         return length;
2148 }
2149
2150 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2151                                      ffs_entity_callback entity, void *priv)
2152 {
2153         const unsigned _len = len;
2154         unsigned long num = 0;
2155         int current_class = -1;
2156
2157         ENTER();
2158
2159         for (;;) {
2160                 int ret;
2161
2162                 if (num == count)
2163                         data = NULL;
2164
2165                 /* Record "descriptor" entity */
2166                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2167                 if (ret < 0) {
2168                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2169                                  num, ret);
2170                         return ret;
2171                 }
2172
2173                 if (!data)
2174                         return _len - len;
2175
2176                 ret = ffs_do_single_desc(data, len, entity, priv,
2177                         &current_class);
2178                 if (ret < 0) {
2179                         pr_debug("%s returns %d\n", __func__, ret);
2180                         return ret;
2181                 }
2182
2183                 len -= ret;
2184                 data += ret;
2185                 ++num;
2186         }
2187 }
2188
2189 static int __ffs_data_do_entity(enum ffs_entity_type type,
2190                                 u8 *valuep, struct usb_descriptor_header *desc,
2191                                 void *priv)
2192 {
2193         struct ffs_desc_helper *helper = priv;
2194         struct usb_endpoint_descriptor *d;
2195
2196         ENTER();
2197
2198         switch (type) {
2199         case FFS_DESCRIPTOR:
2200                 break;
2201
2202         case FFS_INTERFACE:
2203                 /*
2204                  * Interfaces are indexed from zero so if we
2205                  * encountered interface "n" then there are at least
2206                  * "n+1" interfaces.
2207                  */
2208                 if (*valuep >= helper->interfaces_count)
2209                         helper->interfaces_count = *valuep + 1;
2210                 break;
2211
2212         case FFS_STRING:
2213                 /*
2214                  * Strings are indexed from 1 (0 is reserved
2215                  * for languages list)
2216                  */
2217                 if (*valuep > helper->ffs->strings_count)
2218                         helper->ffs->strings_count = *valuep;
2219                 break;
2220
2221         case FFS_ENDPOINT:
2222                 d = (void *)desc;
2223                 helper->eps_count++;
2224                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2225                         return -EINVAL;
2226                 /* Check if descriptors for any speed were already parsed */
2227                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2228                         helper->ffs->eps_addrmap[helper->eps_count] =
2229                                 d->bEndpointAddress;
2230                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2231                                 d->bEndpointAddress)
2232                         return -EINVAL;
2233                 break;
2234         }
2235
2236         return 0;
2237 }
2238
2239 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2240                                    struct usb_os_desc_header *desc)
2241 {
2242         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2243         u16 w_index = le16_to_cpu(desc->wIndex);
2244
2245         if (bcd_version != 1) {
2246                 pr_vdebug("unsupported os descriptors version: %d",
2247                           bcd_version);
2248                 return -EINVAL;
2249         }
2250         switch (w_index) {
2251         case 0x4:
2252                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2253                 break;
2254         case 0x5:
2255                 *next_type = FFS_OS_DESC_EXT_PROP;
2256                 break;
2257         default:
2258                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2259                 return -EINVAL;
2260         }
2261
2262         return sizeof(*desc);
2263 }
2264
2265 /*
2266  * Process all extended compatibility/extended property descriptors
2267  * of a feature descriptor
2268  */
2269 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2270                                               enum ffs_os_desc_type type,
2271                                               u16 feature_count,
2272                                               ffs_os_desc_callback entity,
2273                                               void *priv,
2274                                               struct usb_os_desc_header *h)
2275 {
2276         int ret;
2277         const unsigned _len = len;
2278
2279         ENTER();
2280
2281         /* loop over all ext compat/ext prop descriptors */
2282         while (feature_count--) {
2283                 ret = entity(type, h, data, len, priv);
2284                 if (ret < 0) {
2285                         pr_debug("bad OS descriptor, type: %d\n", type);
2286                         return ret;
2287                 }
2288                 data += ret;
2289                 len -= ret;
2290         }
2291         return _len - len;
2292 }
2293
2294 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2295 static int __must_check ffs_do_os_descs(unsigned count,
2296                                         char *data, unsigned len,
2297                                         ffs_os_desc_callback entity, void *priv)
2298 {
2299         const unsigned _len = len;
2300         unsigned long num = 0;
2301
2302         ENTER();
2303
2304         for (num = 0; num < count; ++num) {
2305                 int ret;
2306                 enum ffs_os_desc_type type;
2307                 u16 feature_count;
2308                 struct usb_os_desc_header *desc = (void *)data;
2309
2310                 if (len < sizeof(*desc))
2311                         return -EINVAL;
2312
2313                 /*
2314                  * Record "descriptor" entity.
2315                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2316                  * Move the data pointer to the beginning of extended
2317                  * compatibilities proper or extended properties proper
2318                  * portions of the data
2319                  */
2320                 if (le32_to_cpu(desc->dwLength) > len)
2321                         return -EINVAL;
2322
2323                 ret = __ffs_do_os_desc_header(&type, desc);
2324                 if (ret < 0) {
2325                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2326                                  num, ret);
2327                         return ret;
2328                 }
2329                 /*
2330                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2331                  */
2332                 feature_count = le16_to_cpu(desc->wCount);
2333                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2334                     (feature_count > 255 || desc->Reserved))
2335                                 return -EINVAL;
2336                 len -= ret;
2337                 data += ret;
2338
2339                 /*
2340                  * Process all function/property descriptors
2341                  * of this Feature Descriptor
2342                  */
2343                 ret = ffs_do_single_os_desc(data, len, type,
2344                                             feature_count, entity, priv, desc);
2345                 if (ret < 0) {
2346                         pr_debug("%s returns %d\n", __func__, ret);
2347                         return ret;
2348                 }
2349
2350                 len -= ret;
2351                 data += ret;
2352         }
2353         return _len - len;
2354 }
2355
2356 /*
2357  * Validate contents of the buffer from userspace related to OS descriptors.
2358  */
2359 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2360                                  struct usb_os_desc_header *h, void *data,
2361                                  unsigned len, void *priv)
2362 {
2363         struct ffs_data *ffs = priv;
2364         u8 length;
2365
2366         ENTER();
2367
2368         switch (type) {
2369         case FFS_OS_DESC_EXT_COMPAT: {
2370                 struct usb_ext_compat_desc *d = data;
2371                 int i;
2372
2373                 if (len < sizeof(*d) ||
2374                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2375                         return -EINVAL;
2376                 if (d->Reserved1 != 1) {
2377                         /*
2378                          * According to the spec, Reserved1 must be set to 1
2379                          * but older kernels incorrectly rejected non-zero
2380                          * values.  We fix it here to avoid returning EINVAL
2381                          * in response to values we used to accept.
2382                          */
2383                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2384                         d->Reserved1 = 1;
2385                 }
2386                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2387                         if (d->Reserved2[i])
2388                                 return -EINVAL;
2389
2390                 length = sizeof(struct usb_ext_compat_desc);
2391         }
2392                 break;
2393         case FFS_OS_DESC_EXT_PROP: {
2394                 struct usb_ext_prop_desc *d = data;
2395                 u32 type, pdl;
2396                 u16 pnl;
2397
2398                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2399                         return -EINVAL;
2400                 length = le32_to_cpu(d->dwSize);
2401                 if (len < length)
2402                         return -EINVAL;
2403                 type = le32_to_cpu(d->dwPropertyDataType);
2404                 if (type < USB_EXT_PROP_UNICODE ||
2405                     type > USB_EXT_PROP_UNICODE_MULTI) {
2406                         pr_vdebug("unsupported os descriptor property type: %d",
2407                                   type);
2408                         return -EINVAL;
2409                 }
2410                 pnl = le16_to_cpu(d->wPropertyNameLength);
2411                 if (length < 14 + pnl) {
2412                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2413                                   length, pnl, type);
2414                         return -EINVAL;
2415                 }
2416                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2417                 if (length != 14 + pnl + pdl) {
2418                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2419                                   length, pnl, pdl, type);
2420                         return -EINVAL;
2421                 }
2422                 ++ffs->ms_os_descs_ext_prop_count;
2423                 /* property name reported to the host as "WCHAR"s */
2424                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2425                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2426         }
2427                 break;
2428         default:
2429                 pr_vdebug("unknown descriptor: %d\n", type);
2430                 return -EINVAL;
2431         }
2432         return length;
2433 }
2434
2435 static int __ffs_data_got_descs(struct ffs_data *ffs,
2436                                 char *const _data, size_t len)
2437 {
2438         char *data = _data, *raw_descs;
2439         unsigned os_descs_count = 0, counts[3], flags;
2440         int ret = -EINVAL, i;
2441         struct ffs_desc_helper helper;
2442
2443         ENTER();
2444
2445         if (get_unaligned_le32(data + 4) != len)
2446                 goto error;
2447
2448         switch (get_unaligned_le32(data)) {
2449         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2450                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2451                 data += 8;
2452                 len  -= 8;
2453                 break;
2454         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2455                 flags = get_unaligned_le32(data + 8);
2456                 ffs->user_flags = flags;
2457                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2458                               FUNCTIONFS_HAS_HS_DESC |
2459                               FUNCTIONFS_HAS_SS_DESC |
2460                               FUNCTIONFS_HAS_MS_OS_DESC |
2461                               FUNCTIONFS_VIRTUAL_ADDR |
2462                               FUNCTIONFS_EVENTFD |
2463                               FUNCTIONFS_ALL_CTRL_RECIP |
2464                               FUNCTIONFS_CONFIG0_SETUP)) {
2465                         ret = -ENOSYS;
2466                         goto error;
2467                 }
2468                 data += 12;
2469                 len  -= 12;
2470                 break;
2471         default:
2472                 goto error;
2473         }
2474
2475         if (flags & FUNCTIONFS_EVENTFD) {
2476                 if (len < 4)
2477                         goto error;
2478                 ffs->ffs_eventfd =
2479                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2480                 if (IS_ERR(ffs->ffs_eventfd)) {
2481                         ret = PTR_ERR(ffs->ffs_eventfd);
2482                         ffs->ffs_eventfd = NULL;
2483                         goto error;
2484                 }
2485                 data += 4;
2486                 len  -= 4;
2487         }
2488
2489         /* Read fs_count, hs_count and ss_count (if present) */
2490         for (i = 0; i < 3; ++i) {
2491                 if (!(flags & (1 << i))) {
2492                         counts[i] = 0;
2493                 } else if (len < 4) {
2494                         goto error;
2495                 } else {
2496                         counts[i] = get_unaligned_le32(data);
2497                         data += 4;
2498                         len  -= 4;
2499                 }
2500         }
2501         if (flags & (1 << i)) {
2502                 if (len < 4) {
2503                         goto error;
2504                 }
2505                 os_descs_count = get_unaligned_le32(data);
2506                 data += 4;
2507                 len -= 4;
2508         }
2509
2510         /* Read descriptors */
2511         raw_descs = data;
2512         helper.ffs = ffs;
2513         for (i = 0; i < 3; ++i) {
2514                 if (!counts[i])
2515                         continue;
2516                 helper.interfaces_count = 0;
2517                 helper.eps_count = 0;
2518                 ret = ffs_do_descs(counts[i], data, len,
2519                                    __ffs_data_do_entity, &helper);
2520                 if (ret < 0)
2521                         goto error;
2522                 if (!ffs->eps_count && !ffs->interfaces_count) {
2523                         ffs->eps_count = helper.eps_count;
2524                         ffs->interfaces_count = helper.interfaces_count;
2525                 } else {
2526                         if (ffs->eps_count != helper.eps_count) {
2527                                 ret = -EINVAL;
2528                                 goto error;
2529                         }
2530                         if (ffs->interfaces_count != helper.interfaces_count) {
2531                                 ret = -EINVAL;
2532                                 goto error;
2533                         }
2534                 }
2535                 data += ret;
2536                 len  -= ret;
2537         }
2538         if (os_descs_count) {
2539                 ret = ffs_do_os_descs(os_descs_count, data, len,
2540                                       __ffs_data_do_os_desc, ffs);
2541                 if (ret < 0)
2542                         goto error;
2543                 data += ret;
2544                 len -= ret;
2545         }
2546
2547         if (raw_descs == data || len) {
2548                 ret = -EINVAL;
2549                 goto error;
2550         }
2551
2552         ffs->raw_descs_data     = _data;
2553         ffs->raw_descs          = raw_descs;
2554         ffs->raw_descs_length   = data - raw_descs;
2555         ffs->fs_descs_count     = counts[0];
2556         ffs->hs_descs_count     = counts[1];
2557         ffs->ss_descs_count     = counts[2];
2558         ffs->ms_os_descs_count  = os_descs_count;
2559
2560         return 0;
2561
2562 error:
2563         kfree(_data);
2564         return ret;
2565 }
2566
2567 static int __ffs_data_got_strings(struct ffs_data *ffs,
2568                                   char *const _data, size_t len)
2569 {
2570         u32 str_count, needed_count, lang_count;
2571         struct usb_gadget_strings **stringtabs, *t;
2572         const char *data = _data;
2573         struct usb_string *s;
2574
2575         ENTER();
2576
2577         if (len < 16 ||
2578             get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2579             get_unaligned_le32(data + 4) != len)
2580                 goto error;
2581         str_count  = get_unaligned_le32(data + 8);
2582         lang_count = get_unaligned_le32(data + 12);
2583
2584         /* if one is zero the other must be zero */
2585         if (!str_count != !lang_count)
2586                 goto error;
2587
2588         /* Do we have at least as many strings as descriptors need? */
2589         needed_count = ffs->strings_count;
2590         if (str_count < needed_count)
2591                 goto error;
2592
2593         /*
2594          * If we don't need any strings just return and free all
2595          * memory.
2596          */
2597         if (!needed_count) {
2598                 kfree(_data);
2599                 return 0;
2600         }
2601
2602         /* Allocate everything in one chunk so there's less maintenance. */
2603         {
2604                 unsigned i = 0;
2605                 vla_group(d);
2606                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2607                         lang_count + 1);
2608                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2609                 vla_item(d, struct usb_string, strings,
2610                         lang_count*(needed_count+1));
2611
2612                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2613
2614                 if (!vlabuf) {
2615                         kfree(_data);
2616                         return -ENOMEM;
2617                 }
2618
2619                 /* Initialize the VLA pointers */
2620                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2621                 t = vla_ptr(vlabuf, d, stringtab);
2622                 i = lang_count;
2623                 do {
2624                         *stringtabs++ = t++;
2625                 } while (--i);
2626                 *stringtabs = NULL;
2627
2628                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2629                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2630                 t = vla_ptr(vlabuf, d, stringtab);
2631                 s = vla_ptr(vlabuf, d, strings);
2632         }
2633
2634         /* For each language */
2635         data += 16;
2636         len -= 16;
2637
2638         do { /* lang_count > 0 so we can use do-while */
2639                 unsigned needed = needed_count;
2640                 u32 str_per_lang = str_count;
2641
2642                 if (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 (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 (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_per_lang);
2677
2678                 s->id = 0;   /* terminator */
2679                 s->s = NULL;
2680                 ++s;
2681
2682         } while (--lang_count);
2683
2684         /* Some garbage left? */
2685         if (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 (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 (!ep)
2864                         return -ENOTSUPP;
2865                 ep->driver_data = func->eps + idx;
2866
2867                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2868                 if (!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 (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 (!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         struct ffs_data *ffs_data;
3033         int ret;
3034
3035         ENTER();
3036
3037         /*
3038          * Legacy gadget triggers binding in functionfs_ready_callback,
3039          * which already uses locking; taking the same lock here would
3040          * cause a deadlock.
3041          *
3042          * Configfs-enabled gadgets however do need ffs_dev_lock.
3043          */
3044         if (!ffs_opts->no_configfs)
3045                 ffs_dev_lock();
3046         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3047         ffs_data = ffs_opts->dev->ffs_data;
3048         if (!ffs_opts->no_configfs)
3049                 ffs_dev_unlock();
3050         if (ret)
3051                 return ERR_PTR(ret);
3052
3053         func->ffs = ffs_data;
3054         func->conf = c;
3055         func->gadget = c->cdev->gadget;
3056
3057         /*
3058          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3059          * configurations are bound in sequence with list_for_each_entry,
3060          * in each configuration its functions are bound in sequence
3061          * with list_for_each_entry, so we assume no race condition
3062          * with regard to ffs_opts->bound access
3063          */
3064         if (!ffs_opts->refcnt) {
3065                 ret = functionfs_bind(func->ffs, c->cdev);
3066                 if (ret)
3067                         return ERR_PTR(ret);
3068         }
3069         ffs_opts->refcnt++;
3070         func->function.strings = func->ffs->stringtabs;
3071
3072         return ffs_opts;
3073 }
3074
3075 static int _ffs_func_bind(struct usb_configuration *c,
3076                           struct usb_function *f)
3077 {
3078         struct ffs_function *func = ffs_func_from_usb(f);
3079         struct ffs_data *ffs = func->ffs;
3080
3081         const int full = !!func->ffs->fs_descs_count;
3082         const int high = !!func->ffs->hs_descs_count;
3083         const int super = !!func->ffs->ss_descs_count;
3084
3085         int fs_len, hs_len, ss_len, ret, i;
3086         struct ffs_ep *eps_ptr;
3087
3088         /* Make it a single chunk, less management later on */
3089         vla_group(d);
3090         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3091         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3092                 full ? ffs->fs_descs_count + 1 : 0);
3093         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3094                 high ? ffs->hs_descs_count + 1 : 0);
3095         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3096                 super ? ffs->ss_descs_count + 1 : 0);
3097         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3098         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3099                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3100         vla_item_with_sz(d, char[16], ext_compat,
3101                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3102         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3103                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3104         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3105                          ffs->ms_os_descs_ext_prop_count);
3106         vla_item_with_sz(d, char, ext_prop_name,
3107                          ffs->ms_os_descs_ext_prop_name_len);
3108         vla_item_with_sz(d, char, ext_prop_data,
3109                          ffs->ms_os_descs_ext_prop_data_len);
3110         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3111         char *vlabuf;
3112
3113         ENTER();
3114
3115         /* Has descriptors only for speeds gadget does not support */
3116         if (!(full | high | super))
3117                 return -ENOTSUPP;
3118
3119         /* Allocate a single chunk, less management later on */
3120         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3121         if (!vlabuf)
3122                 return -ENOMEM;
3123
3124         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3125         ffs->ms_os_descs_ext_prop_name_avail =
3126                 vla_ptr(vlabuf, d, ext_prop_name);
3127         ffs->ms_os_descs_ext_prop_data_avail =
3128                 vla_ptr(vlabuf, d, ext_prop_data);
3129
3130         /* Copy descriptors  */
3131         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3132                ffs->raw_descs_length);
3133
3134         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3135         eps_ptr = vla_ptr(vlabuf, d, eps);
3136         for (i = 0; i < ffs->eps_count; i++)
3137                 eps_ptr[i].num = -1;
3138
3139         /* Save pointers
3140          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3141         */
3142         func->eps             = vla_ptr(vlabuf, d, eps);
3143         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3144
3145         /*
3146          * Go through all the endpoint descriptors and allocate
3147          * endpoints first, so that later we can rewrite the endpoint
3148          * numbers without worrying that it may be described later on.
3149          */
3150         if (full) {
3151                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3152                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3153                                       vla_ptr(vlabuf, d, raw_descs),
3154                                       d_raw_descs__sz,
3155                                       __ffs_func_bind_do_descs, func);
3156                 if (fs_len < 0) {
3157                         ret = fs_len;
3158                         goto error;
3159                 }
3160         } else {
3161                 fs_len = 0;
3162         }
3163
3164         if (high) {
3165                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3166                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3167                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3168                                       d_raw_descs__sz - fs_len,
3169                                       __ffs_func_bind_do_descs, func);
3170                 if (hs_len < 0) {
3171                         ret = hs_len;
3172                         goto error;
3173                 }
3174         } else {
3175                 hs_len = 0;
3176         }
3177
3178         if (super) {
3179                 func->function.ss_descriptors = func->function.ssp_descriptors =
3180                         vla_ptr(vlabuf, d, ss_descs);
3181                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3182                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3183                                 d_raw_descs__sz - fs_len - hs_len,
3184                                 __ffs_func_bind_do_descs, func);
3185                 if (ss_len < 0) {
3186                         ret = ss_len;
3187                         goto error;
3188                 }
3189         } else {
3190                 ss_len = 0;
3191         }
3192
3193         /*
3194          * Now handle interface numbers allocation and interface and
3195          * endpoint numbers rewriting.  We can do that in one go
3196          * now.
3197          */
3198         ret = ffs_do_descs(ffs->fs_descs_count +
3199                            (high ? ffs->hs_descs_count : 0) +
3200                            (super ? ffs->ss_descs_count : 0),
3201                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3202                            __ffs_func_bind_do_nums, func);
3203         if (ret < 0)
3204                 goto error;
3205
3206         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3207         if (c->cdev->use_os_string) {
3208                 for (i = 0; i < ffs->interfaces_count; ++i) {
3209                         struct usb_os_desc *desc;
3210
3211                         desc = func->function.os_desc_table[i].os_desc =
3212                                 vla_ptr(vlabuf, d, os_desc) +
3213                                 i * sizeof(struct usb_os_desc);
3214                         desc->ext_compat_id =
3215                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3216                         INIT_LIST_HEAD(&desc->ext_prop);
3217                 }
3218                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3219                                       vla_ptr(vlabuf, d, raw_descs) +
3220                                       fs_len + hs_len + ss_len,
3221                                       d_raw_descs__sz - fs_len - hs_len -
3222                                       ss_len,
3223                                       __ffs_func_bind_do_os_desc, func);
3224                 if (ret < 0)
3225                         goto error;
3226         }
3227         func->function.os_desc_n =
3228                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3229
3230         /* And we're done */
3231         ffs_event_add(ffs, FUNCTIONFS_BIND);
3232         return 0;
3233
3234 error:
3235         /* XXX Do we need to release all claimed endpoints here? */
3236         return ret;
3237 }
3238
3239 static int ffs_func_bind(struct usb_configuration *c,
3240                          struct usb_function *f)
3241 {
3242         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3243         struct ffs_function *func = ffs_func_from_usb(f);
3244         int ret;
3245
3246         if (IS_ERR(ffs_opts))
3247                 return PTR_ERR(ffs_opts);
3248
3249         ret = _ffs_func_bind(c, f);
3250         if (ret && !--ffs_opts->refcnt)
3251                 functionfs_unbind(func->ffs);
3252
3253         return ret;
3254 }
3255
3256
3257 /* Other USB function hooks *************************************************/
3258
3259 static void ffs_reset_work(struct work_struct *work)
3260 {
3261         struct ffs_data *ffs = container_of(work,
3262                 struct ffs_data, reset_work);
3263         ffs_data_reset(ffs);
3264 }
3265
3266 static int ffs_func_set_alt(struct usb_function *f,
3267                             unsigned interface, unsigned alt)
3268 {
3269         struct ffs_function *func = ffs_func_from_usb(f);
3270         struct ffs_data *ffs = func->ffs;
3271         int ret = 0, intf;
3272
3273         if (alt != (unsigned)-1) {
3274                 intf = ffs_func_revmap_intf(func, interface);
3275                 if (intf < 0)
3276                         return intf;
3277         }
3278
3279         if (ffs->func)
3280                 ffs_func_eps_disable(ffs->func);
3281
3282         if (ffs->state == FFS_DEACTIVATED) {
3283                 ffs->state = FFS_CLOSING;
3284                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3285                 schedule_work(&ffs->reset_work);
3286                 return -ENODEV;
3287         }
3288
3289         if (ffs->state != FFS_ACTIVE)
3290                 return -ENODEV;
3291
3292         if (alt == (unsigned)-1) {
3293                 ffs->func = NULL;
3294                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3295                 return 0;
3296         }
3297
3298         ffs->func = func;
3299         ret = ffs_func_eps_enable(func);
3300         if (ret >= 0)
3301                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3302         return ret;
3303 }
3304
3305 static void ffs_func_disable(struct usb_function *f)
3306 {
3307         ffs_func_set_alt(f, 0, (unsigned)-1);
3308 }
3309
3310 static int ffs_func_setup(struct usb_function *f,
3311                           const struct usb_ctrlrequest *creq)
3312 {
3313         struct ffs_function *func = ffs_func_from_usb(f);
3314         struct ffs_data *ffs = func->ffs;
3315         unsigned long flags;
3316         int ret;
3317
3318         ENTER();
3319
3320         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3321         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3322         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3323         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3324         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3325
3326         /*
3327          * Most requests directed to interface go through here
3328          * (notable exceptions are set/get interface) so we need to
3329          * handle them.  All other either handled by composite or
3330          * passed to usb_configuration->setup() (if one is set).  No
3331          * matter, we will handle requests directed to endpoint here
3332          * as well (as it's straightforward).  Other request recipient
3333          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3334          * is being used.
3335          */
3336         if (ffs->state != FFS_ACTIVE)
3337                 return -ENODEV;
3338
3339         switch (creq->bRequestType & USB_RECIP_MASK) {
3340         case USB_RECIP_INTERFACE:
3341                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3342                 if (ret < 0)
3343                         return ret;
3344                 break;
3345
3346         case USB_RECIP_ENDPOINT:
3347                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3348                 if (ret < 0)
3349                         return ret;
3350                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3351                         ret = func->ffs->eps_addrmap[ret];
3352                 break;
3353
3354         default:
3355                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3356                         ret = le16_to_cpu(creq->wIndex);
3357                 else
3358                         return -EOPNOTSUPP;
3359         }
3360
3361         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3362         ffs->ev.setup = *creq;
3363         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3364         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3365         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3366
3367         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3368 }
3369
3370 static bool ffs_func_req_match(struct usb_function *f,
3371                                const struct usb_ctrlrequest *creq,
3372                                bool config0)
3373 {
3374         struct ffs_function *func = ffs_func_from_usb(f);
3375
3376         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3377                 return false;
3378
3379         switch (creq->bRequestType & USB_RECIP_MASK) {
3380         case USB_RECIP_INTERFACE:
3381                 return (ffs_func_revmap_intf(func,
3382                                              le16_to_cpu(creq->wIndex)) >= 0);
3383         case USB_RECIP_ENDPOINT:
3384                 return (ffs_func_revmap_ep(func,
3385                                            le16_to_cpu(creq->wIndex)) >= 0);
3386         default:
3387                 return (bool) (func->ffs->user_flags &
3388                                FUNCTIONFS_ALL_CTRL_RECIP);
3389         }
3390 }
3391
3392 static void ffs_func_suspend(struct usb_function *f)
3393 {
3394         ENTER();
3395         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3396 }
3397
3398 static void ffs_func_resume(struct usb_function *f)
3399 {
3400         ENTER();
3401         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3402 }
3403
3404
3405 /* Endpoint and interface numbers reverse mapping ***************************/
3406
3407 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3408 {
3409         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3410         return num ? num : -EDOM;
3411 }
3412
3413 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3414 {
3415         short *nums = func->interfaces_nums;
3416         unsigned count = func->ffs->interfaces_count;
3417
3418         for (; count; --count, ++nums) {
3419                 if (*nums >= 0 && *nums == intf)
3420                         return nums - func->interfaces_nums;
3421         }
3422
3423         return -EDOM;
3424 }
3425
3426
3427 /* Devices management *******************************************************/
3428
3429 static LIST_HEAD(ffs_devices);
3430
3431 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3432 {
3433         struct ffs_dev *dev;
3434
3435         if (!name)
3436                 return NULL;
3437
3438         list_for_each_entry(dev, &ffs_devices, entry) {
3439                 if (strcmp(dev->name, name) == 0)
3440                         return dev;
3441         }
3442
3443         return NULL;
3444 }
3445
3446 /*
3447  * ffs_lock must be taken by the caller of this function
3448  */
3449 static struct ffs_dev *_ffs_get_single_dev(void)
3450 {
3451         struct ffs_dev *dev;
3452
3453         if (list_is_singular(&ffs_devices)) {
3454                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3455                 if (dev->single)
3456                         return dev;
3457         }
3458
3459         return NULL;
3460 }
3461
3462 /*
3463  * ffs_lock must be taken by the caller of this function
3464  */
3465 static struct ffs_dev *_ffs_find_dev(const char *name)
3466 {
3467         struct ffs_dev *dev;
3468
3469         dev = _ffs_get_single_dev();
3470         if (dev)
3471                 return dev;
3472
3473         return _ffs_do_find_dev(name);
3474 }
3475
3476 /* Configfs support *********************************************************/
3477
3478 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3479 {
3480         return container_of(to_config_group(item), struct f_fs_opts,
3481                             func_inst.group);
3482 }
3483
3484 static void ffs_attr_release(struct config_item *item)
3485 {
3486         struct f_fs_opts *opts = to_ffs_opts(item);
3487
3488         usb_put_function_instance(&opts->func_inst);
3489 }
3490
3491 static struct configfs_item_operations ffs_item_ops = {
3492         .release        = ffs_attr_release,
3493 };
3494
3495 static const struct config_item_type ffs_func_type = {
3496         .ct_item_ops    = &ffs_item_ops,
3497         .ct_owner       = THIS_MODULE,
3498 };
3499
3500
3501 /* Function registration interface ******************************************/
3502
3503 static void ffs_free_inst(struct usb_function_instance *f)
3504 {
3505         struct f_fs_opts *opts;
3506
3507         opts = to_f_fs_opts(f);
3508         ffs_release_dev(opts->dev);
3509         ffs_dev_lock();
3510         _ffs_free_dev(opts->dev);
3511         ffs_dev_unlock();
3512         kfree(opts);
3513 }
3514
3515 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3516 {
3517         if (strlen(name) >= sizeof_field(struct ffs_dev, name))
3518                 return -ENAMETOOLONG;
3519         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3520 }
3521
3522 static struct usb_function_instance *ffs_alloc_inst(void)
3523 {
3524         struct f_fs_opts *opts;
3525         struct ffs_dev *dev;
3526
3527         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3528         if (!opts)
3529                 return ERR_PTR(-ENOMEM);
3530
3531         opts->func_inst.set_inst_name = ffs_set_inst_name;
3532         opts->func_inst.free_func_inst = ffs_free_inst;
3533         ffs_dev_lock();
3534         dev = _ffs_alloc_dev();
3535         ffs_dev_unlock();
3536         if (IS_ERR(dev)) {
3537                 kfree(opts);
3538                 return ERR_CAST(dev);
3539         }
3540         opts->dev = dev;
3541         dev->opts = opts;
3542
3543         config_group_init_type_name(&opts->func_inst.group, "",
3544                                     &ffs_func_type);
3545         return &opts->func_inst;
3546 }
3547
3548 static void ffs_free(struct usb_function *f)
3549 {
3550         kfree(ffs_func_from_usb(f));
3551 }
3552
3553 static void ffs_func_unbind(struct usb_configuration *c,
3554                             struct usb_function *f)
3555 {
3556         struct ffs_function *func = ffs_func_from_usb(f);
3557         struct ffs_data *ffs = func->ffs;
3558         struct f_fs_opts *opts =
3559                 container_of(f->fi, struct f_fs_opts, func_inst);
3560         struct ffs_ep *ep = func->eps;
3561         unsigned count = ffs->eps_count;
3562         unsigned long flags;
3563
3564         ENTER();
3565         if (ffs->func == func) {
3566                 ffs_func_eps_disable(func);
3567                 ffs->func = NULL;
3568         }
3569
3570         /* Drain any pending AIO completions */
3571         drain_workqueue(ffs->io_completion_wq);
3572
3573         if (!--opts->refcnt)
3574                 functionfs_unbind(ffs);
3575
3576         /* cleanup after autoconfig */
3577         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3578         while (count--) {
3579                 if (ep->ep && ep->req)
3580                         usb_ep_free_request(ep->ep, ep->req);
3581                 ep->req = NULL;
3582                 ++ep;
3583         }
3584         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3585         kfree(func->eps);
3586         func->eps = NULL;
3587         /*
3588          * eps, descriptors and interfaces_nums are allocated in the
3589          * same chunk so only one free is required.
3590          */
3591         func->function.fs_descriptors = NULL;
3592         func->function.hs_descriptors = NULL;
3593         func->function.ss_descriptors = NULL;
3594         func->function.ssp_descriptors = NULL;
3595         func->interfaces_nums = NULL;
3596
3597         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3598 }
3599
3600 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3601 {
3602         struct ffs_function *func;
3603
3604         ENTER();
3605
3606         func = kzalloc(sizeof(*func), GFP_KERNEL);
3607         if (!func)
3608                 return ERR_PTR(-ENOMEM);
3609
3610         func->function.name    = "Function FS Gadget";
3611
3612         func->function.bind    = ffs_func_bind;
3613         func->function.unbind  = ffs_func_unbind;
3614         func->function.set_alt = ffs_func_set_alt;
3615         func->function.disable = ffs_func_disable;
3616         func->function.setup   = ffs_func_setup;
3617         func->function.req_match = ffs_func_req_match;
3618         func->function.suspend = ffs_func_suspend;
3619         func->function.resume  = ffs_func_resume;
3620         func->function.free_func = ffs_free;
3621
3622         return &func->function;
3623 }
3624
3625 /*
3626  * ffs_lock must be taken by the caller of this function
3627  */
3628 static struct ffs_dev *_ffs_alloc_dev(void)
3629 {
3630         struct ffs_dev *dev;
3631         int ret;
3632
3633         if (_ffs_get_single_dev())
3634                         return ERR_PTR(-EBUSY);
3635
3636         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3637         if (!dev)
3638                 return ERR_PTR(-ENOMEM);
3639
3640         if (list_empty(&ffs_devices)) {
3641                 ret = functionfs_init();
3642                 if (ret) {
3643                         kfree(dev);
3644                         return ERR_PTR(ret);
3645                 }
3646         }
3647
3648         list_add(&dev->entry, &ffs_devices);
3649
3650         return dev;
3651 }
3652
3653 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3654 {
3655         struct ffs_dev *existing;
3656         int ret = 0;
3657
3658         ffs_dev_lock();
3659
3660         existing = _ffs_do_find_dev(name);
3661         if (!existing)
3662                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3663         else if (existing != dev)
3664                 ret = -EBUSY;
3665
3666         ffs_dev_unlock();
3667
3668         return ret;
3669 }
3670 EXPORT_SYMBOL_GPL(ffs_name_dev);
3671
3672 int ffs_single_dev(struct ffs_dev *dev)
3673 {
3674         int ret;
3675
3676         ret = 0;
3677         ffs_dev_lock();
3678
3679         if (!list_is_singular(&ffs_devices))
3680                 ret = -EBUSY;
3681         else
3682                 dev->single = true;
3683
3684         ffs_dev_unlock();
3685         return ret;
3686 }
3687 EXPORT_SYMBOL_GPL(ffs_single_dev);
3688
3689 /*
3690  * ffs_lock must be taken by the caller of this function
3691  */
3692 static void _ffs_free_dev(struct ffs_dev *dev)
3693 {
3694         list_del(&dev->entry);
3695
3696         kfree(dev);
3697         if (list_empty(&ffs_devices))
3698                 functionfs_cleanup();
3699 }
3700
3701 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data)
3702 {
3703         int ret = 0;
3704         struct ffs_dev *ffs_dev;
3705
3706         ENTER();
3707         ffs_dev_lock();
3708
3709         ffs_dev = _ffs_find_dev(dev_name);
3710         if (!ffs_dev) {
3711                 ret = -ENOENT;
3712         } else if (ffs_dev->mounted) {
3713                 ret = -EBUSY;
3714         } else if (ffs_dev->ffs_acquire_dev_callback &&
3715                    ffs_dev->ffs_acquire_dev_callback(ffs_dev)) {
3716                 ret = -ENOENT;
3717         } else {
3718                 ffs_dev->mounted = true;
3719                 ffs_dev->ffs_data = ffs_data;
3720                 ffs_data->private_data = ffs_dev;
3721         }
3722
3723         ffs_dev_unlock();
3724         return ret;
3725 }
3726
3727 static void ffs_release_dev(struct ffs_dev *ffs_dev)
3728 {
3729         ENTER();
3730         ffs_dev_lock();
3731
3732         if (ffs_dev && ffs_dev->mounted) {
3733                 ffs_dev->mounted = false;
3734                 if (ffs_dev->ffs_data) {
3735                         ffs_dev->ffs_data->private_data = NULL;
3736                         ffs_dev->ffs_data = NULL;
3737                 }
3738
3739                 if (ffs_dev->ffs_release_dev_callback)
3740                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3741         }
3742
3743         ffs_dev_unlock();
3744 }
3745
3746 static int ffs_ready(struct ffs_data *ffs)
3747 {
3748         struct ffs_dev *ffs_obj;
3749         int ret = 0;
3750
3751         ENTER();
3752         ffs_dev_lock();
3753
3754         ffs_obj = ffs->private_data;
3755         if (!ffs_obj) {
3756                 ret = -EINVAL;
3757                 goto done;
3758         }
3759         if (WARN_ON(ffs_obj->desc_ready)) {
3760                 ret = -EBUSY;
3761                 goto done;
3762         }
3763
3764         ffs_obj->desc_ready = true;
3765
3766         if (ffs_obj->ffs_ready_callback) {
3767                 ret = ffs_obj->ffs_ready_callback(ffs);
3768                 if (ret)
3769                         goto done;
3770         }
3771
3772         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3773 done:
3774         ffs_dev_unlock();
3775         return ret;
3776 }
3777
3778 static void ffs_closed(struct ffs_data *ffs)
3779 {
3780         struct ffs_dev *ffs_obj;
3781         struct f_fs_opts *opts;
3782         struct config_item *ci;
3783
3784         ENTER();
3785         ffs_dev_lock();
3786
3787         ffs_obj = ffs->private_data;
3788         if (!ffs_obj)
3789                 goto done;
3790
3791         ffs_obj->desc_ready = false;
3792
3793         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3794             ffs_obj->ffs_closed_callback)
3795                 ffs_obj->ffs_closed_callback(ffs);
3796
3797         if (ffs_obj->opts)
3798                 opts = ffs_obj->opts;
3799         else
3800                 goto done;
3801
3802         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3803             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3804                 goto done;
3805
3806         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3807         ffs_dev_unlock();
3808
3809         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3810                 unregister_gadget_item(ci);
3811         return;
3812 done:
3813         ffs_dev_unlock();
3814 }
3815
3816 /* Misc helper functions ****************************************************/
3817
3818 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3819 {
3820         return nonblock
3821                 ? mutex_trylock(mutex) ? 0 : -EAGAIN
3822                 : mutex_lock_interruptible(mutex);
3823 }
3824
3825 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3826 {
3827         char *data;
3828
3829         if (!len)
3830                 return NULL;
3831
3832         data = memdup_user(buf, len);
3833         if (IS_ERR(data))
3834                 return ERR_PTR(PTR_ERR(data));
3835
3836         pr_vdebug("Buffer from user space:\n");
3837         ffs_dump_mem("", data, len);
3838
3839         return data;
3840 }
3841
3842 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3843 MODULE_LICENSE("GPL");
3844 MODULE_AUTHOR("Michal Nazarewicz");