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
 127 struct ffs_epfile {
 128         /* Protects ep->ep and ep->req. */
 129         struct mutex                    mutex;
 130
 131         struct ffs_data                 *ffs;
 132         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 133
 134         struct dentry                   *dentry;
 135
 136         /*
 137          * Buffer for holding data from partial reads which may happen since
 138          * we’re rounding user read requests to a multiple of a max packet size.
 139          *
 140          * The pointer is initialised with NULL value and may be set by
 141          * __ffs_epfile_read_data function to point to a temporary buffer.
 142          *
 143          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 144          * data from said buffer and eventually free it.  Importantly, while the
 145          * function is using the buffer, it sets the pointer to NULL.  This is
 146          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 147          * can never run concurrently (they are synchronised by epfile->mutex)
 148          * so the latter will not assign a new value to the pointer.
 149          *
 150          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 151          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 152          * value is crux of the synchronisation between ffs_func_eps_disable and
 153          * __ffs_epfile_read_data.
 154          *
 155          * Once __ffs_epfile_read_data is about to finish it will try to set the
 156          * pointer back to its old value (as described above), but seeing as the
 157          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 158          * the buffer.
 159          *
 160          * == State transitions ==
 161          *
 162          * • ptr == NULL:  (initial state)
 163          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 164          *   ◦ __ffs_epfile_read_buffered:    nop
 165          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 166          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 167          * • ptr == DROP:
 168          *   ◦ __ffs_epfile_read_buffer_free: nop
 169          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 170          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 171          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 172          * • ptr == buf:
 173          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 174          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 175          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 176          *                                    is always called first
 177          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 178          * • ptr == NULL and reading:
 179          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 180          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 181          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 182          *   ◦ reading finishes and …
 183          *     … all data read:               free buf, go to ptr == NULL
 184          *     … otherwise:                   go to ptr == buf and reading
 185          * • ptr == DROP and reading:
 186          *   ◦ __ffs_epfile_read_buffer_free: nop
 187          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 188          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 189          *   ◦ reading finishes:              free buf, go to ptr == DROP
 190          */
 191         struct ffs_buffer               *read_buffer;
 192 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 193
 194         char                            name[5];
 195
 196         unsigned char                   in;     /* P: ffs->eps_lock */
 197         unsigned char                   isoc;   /* P: ffs->eps_lock */
 198
 199         unsigned char                   _pad;
 200 };
 201
 202 struct ffs_buffer {
 203         size_t length;
 204         char *data;
 205         char storage[] __counted_by(length);
 206 };
 207
 208 /*  ffs_io_data structure ***************************************************/
 209
 210 struct ffs_io_data {
 211         bool aio;
 212         bool read;
 213
 214         struct kiocb *kiocb;
 215         struct iov_iter data;
 216         const void *to_free;
 217         char *buf;
 218
 219         struct mm_struct *mm;
 220         struct work_struct work;
 221
 222         struct usb_ep *ep;
 223         struct usb_request *req;
 224         struct sg_table sgt;
 225         bool use_sg;
 226
 227         struct ffs_data *ffs;
 228
 229         int status;
 230         struct completion done;
 231 };
 232
 233 struct ffs_desc_helper {
 234         struct ffs_data *ffs;
 235         unsigned interfaces_count;
 236         unsigned eps_count;
 237 };
 238
 239 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 240 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 241
 242 static struct dentry *
 243 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 244                    const struct file_operations *fops);
 245
 246 /* Devices management *******************************************************/
 247
 248 DEFINE_MUTEX(ffs_lock);
 249 EXPORT_SYMBOL_GPL(ffs_lock);
 250
 251 static struct ffs_dev *_ffs_find_dev(const char *name);
 252 static struct ffs_dev *_ffs_alloc_dev(void);
 253 static void _ffs_free_dev(struct ffs_dev *dev);
 254 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data);
 255 static void ffs_release_dev(struct ffs_dev *ffs_dev);
 256 static int ffs_ready(struct ffs_data *ffs);
 257 static void ffs_closed(struct ffs_data *ffs);
 258
 259 /* Misc helper functions ****************************************************/
 260
 261 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 262         __attribute__((warn_unused_result, nonnull));
 263 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 264         __attribute__((warn_unused_result, nonnull));
 265
 266
 267 /* Control file aka ep0 *****************************************************/
 268
 269 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 270 {
 271         struct ffs_data *ffs = req->context;
 272
 273         complete(&ffs->ep0req_completion);
 274 }
 275
 276 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 277         __releases(&ffs->ev.waitq.lock)
 278 {
 279         struct usb_request *req = ffs->ep0req;
 280         int ret;
 281
 282         if (!req) {
 283                 spin_unlock_irq(&ffs->ev.waitq.lock);
 284                 return -EINVAL;
 285         }
 286
 287         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 288
 289         spin_unlock_irq(&ffs->ev.waitq.lock);
 290
 291         req->buf      = data;
 292         req->length   = len;
 293
 294         /*
 295          * UDC layer requires to provide a buffer even for ZLP, but should
 296          * not use it at all. Let's provide some poisoned pointer to catch
 297          * possible bug in the driver.
 298          */
 299         if (req->buf == NULL)
 300                 req->buf = (void *)0xDEADBABE;
 301
 302         reinit_completion(&ffs->ep0req_completion);
 303
 304         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 305         if (ret < 0)
 306                 return ret;
 307
 308         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 309         if (ret) {
 310                 usb_ep_dequeue(ffs->gadget->ep0, req);
 311                 return -EINTR;
 312         }
 313
 314         ffs->setup_state = FFS_NO_SETUP;
 315         return req->status ? req->status : req->actual;
 316 }
 317
 318 static int __ffs_ep0_stall(struct ffs_data *ffs)
 319 {
 320         if (ffs->ev.can_stall) {
 321                 pr_vdebug("ep0 stall\n");
 322                 usb_ep_set_halt(ffs->gadget->ep0);
 323                 ffs->setup_state = FFS_NO_SETUP;
 324                 return -EL2HLT;
 325         } else {
 326                 pr_debug("bogus ep0 stall!\n");
 327                 return -ESRCH;
 328         }
 329 }
 330
 331 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 332                              size_t len, loff_t *ptr)
 333 {
 334         struct ffs_data *ffs = file->private_data;
 335         ssize_t ret;
 336         char *data;
 337
 338         /* Fast check if setup was canceled */
 339         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 340                 return -EIDRM;
 341
 342         /* Acquire mutex */
 343         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 344         if (ret < 0)
 345                 return ret;
 346
 347         /* Check state */
 348         switch (ffs->state) {
 349         case FFS_READ_DESCRIPTORS:
 350         case FFS_READ_STRINGS:
 351                 /* Copy data */
 352                 if (len < 16) {
 353                         ret = -EINVAL;
 354                         break;
 355                 }
 356
 357                 data = ffs_prepare_buffer(buf, len);
 358                 if (IS_ERR(data)) {
 359                         ret = PTR_ERR(data);
 360                         break;
 361                 }
 362
 363                 /* Handle data */
 364                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 365                         pr_info("read descriptors\n");
 366                         ret = __ffs_data_got_descs(ffs, data, len);
 367                         if (ret < 0)
 368                                 break;
 369
 370                         ffs->state = FFS_READ_STRINGS;
 371                         ret = len;
 372                 } else {
 373                         pr_info("read strings\n");
 374                         ret = __ffs_data_got_strings(ffs, data, len);
 375                         if (ret < 0)
 376                                 break;
 377
 378                         ret = ffs_epfiles_create(ffs);
 379                         if (ret) {
 380                                 ffs->state = FFS_CLOSING;
 381                                 break;
 382                         }
 383
 384                         ffs->state = FFS_ACTIVE;
 385                         mutex_unlock(&ffs->mutex);
 386
 387                         ret = ffs_ready(ffs);
 388                         if (ret < 0) {
 389                                 ffs->state = FFS_CLOSING;
 390                                 return ret;
 391                         }
 392
 393                         return len;
 394                 }
 395                 break;
 396
 397         case FFS_ACTIVE:
 398                 data = NULL;
 399                 /*
 400                  * We're called from user space, we can use _irq
 401                  * rather then _irqsave
 402                  */
 403                 spin_lock_irq(&ffs->ev.waitq.lock);
 404                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 405                 case FFS_SETUP_CANCELLED:
 406                         ret = -EIDRM;
 407                         goto done_spin;
 408
 409                 case FFS_NO_SETUP:
 410                         ret = -ESRCH;
 411                         goto done_spin;
 412
 413                 case FFS_SETUP_PENDING:
 414                         break;
 415                 }
 416
 417                 /* FFS_SETUP_PENDING */
 418                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 419                         spin_unlock_irq(&ffs->ev.waitq.lock);
 420                         ret = __ffs_ep0_stall(ffs);
 421                         break;
 422                 }
 423
 424                 /* FFS_SETUP_PENDING and not stall */
 425                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 426
 427                 spin_unlock_irq(&ffs->ev.waitq.lock);
 428
 429                 data = ffs_prepare_buffer(buf, len);
 430                 if (IS_ERR(data)) {
 431                         ret = PTR_ERR(data);
 432                         break;
 433                 }
 434
 435                 spin_lock_irq(&ffs->ev.waitq.lock);
 436
 437                 /*
 438                  * We are guaranteed to be still in FFS_ACTIVE state
 439                  * but the state of setup could have changed from
 440                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 441                  * to check for that.  If that happened we copied data
 442                  * from user space in vain but it's unlikely.
 443                  *
 444                  * For sure we are not in FFS_NO_SETUP since this is
 445                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 446                  * transition can be performed and it's protected by
 447                  * mutex.
 448                  */
 449                 if (ffs_setup_state_clear_cancelled(ffs) ==
 450                     FFS_SETUP_CANCELLED) {
 451                         ret = -EIDRM;
 452 done_spin:
 453                         spin_unlock_irq(&ffs->ev.waitq.lock);
 454                 } else {
 455                         /* unlocks spinlock */
 456                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 457                 }
 458                 kfree(data);
 459                 break;
 460
 461         default:
 462                 ret = -EBADFD;
 463                 break;
 464         }
 465
 466         mutex_unlock(&ffs->mutex);
 467         return ret;
 468 }
 469
 470 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 471 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 472                                      size_t n)
 473         __releases(&ffs->ev.waitq.lock)
 474 {
 475         /*
 476          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 477          * size of ffs->ev.types array (which is four) so that's how much space
 478          * we reserve.
 479          */
 480         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 481         const size_t size = n * sizeof *events;
 482         unsigned i = 0;
 483
 484         memset(events, 0, size);
 485
 486         do {
 487                 events[i].type = ffs->ev.types[i];
 488                 if (events[i].type == FUNCTIONFS_SETUP) {
 489                         events[i].u.setup = ffs->ev.setup;
 490                         ffs->setup_state = FFS_SETUP_PENDING;
 491                 }
 492         } while (++i < n);
 493
 494         ffs->ev.count -= n;
 495         if (ffs->ev.count)
 496                 memmove(ffs->ev.types, ffs->ev.types + n,
 497                         ffs->ev.count * sizeof *ffs->ev.types);
 498
 499         spin_unlock_irq(&ffs->ev.waitq.lock);
 500         mutex_unlock(&ffs->mutex);
 501
 502         return copy_to_user(buf, events, size) ? -EFAULT : size;
 503 }
 504
 505 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 506                             size_t len, loff_t *ptr)
 507 {
 508         struct ffs_data *ffs = file->private_data;
 509         char *data = NULL;
 510         size_t n;
 511         int ret;
 512
 513         /* Fast check if setup was canceled */
 514         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 515                 return -EIDRM;
 516
 517         /* Acquire mutex */
 518         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 519         if (ret < 0)
 520                 return ret;
 521
 522         /* Check state */
 523         if (ffs->state != FFS_ACTIVE) {
 524                 ret = -EBADFD;
 525                 goto done_mutex;
 526         }
 527
 528         /*
 529          * We're called from user space, we can use _irq rather then
 530          * _irqsave
 531          */
 532         spin_lock_irq(&ffs->ev.waitq.lock);
 533
 534         switch (ffs_setup_state_clear_cancelled(ffs)) {
 535         case FFS_SETUP_CANCELLED:
 536                 ret = -EIDRM;
 537                 break;
 538
 539         case FFS_NO_SETUP:
 540                 n = len / sizeof(struct usb_functionfs_event);
 541                 if (!n) {
 542                         ret = -EINVAL;
 543                         break;
 544                 }
 545
 546                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 547                         ret = -EAGAIN;
 548                         break;
 549                 }
 550
 551                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 552                                                         ffs->ev.count)) {
 553                         ret = -EINTR;
 554                         break;
 555                 }
 556
 557                 /* unlocks spinlock */
 558                 return __ffs_ep0_read_events(ffs, buf,
 559                                              min(n, (size_t)ffs->ev.count));
 560
 561         case FFS_SETUP_PENDING:
 562                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 563                         spin_unlock_irq(&ffs->ev.waitq.lock);
 564                         ret = __ffs_ep0_stall(ffs);
 565                         goto done_mutex;
 566                 }
 567
 568                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 569
 570                 spin_unlock_irq(&ffs->ev.waitq.lock);
 571
 572                 if (len) {
 573                         data = kmalloc(len, GFP_KERNEL);
 574                         if (!data) {
 575                                 ret = -ENOMEM;
 576                                 goto done_mutex;
 577                         }
 578                 }
 579
 580                 spin_lock_irq(&ffs->ev.waitq.lock);
 581
 582                 /* See ffs_ep0_write() */
 583                 if (ffs_setup_state_clear_cancelled(ffs) ==
 584                     FFS_SETUP_CANCELLED) {
 585                         ret = -EIDRM;
 586                         break;
 587                 }
 588
 589                 /* unlocks spinlock */
 590                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 591                 if ((ret > 0) && (copy_to_user(buf, data, len)))
 592                         ret = -EFAULT;
 593                 goto done_mutex;
 594
 595         default:
 596                 ret = -EBADFD;
 597                 break;
 598         }
 599
 600         spin_unlock_irq(&ffs->ev.waitq.lock);
 601 done_mutex:
 602         mutex_unlock(&ffs->mutex);
 603         kfree(data);
 604         return ret;
 605 }
 606
 607 static int ffs_ep0_open(struct inode *inode, struct file *file)
 608 {
 609         struct ffs_data *ffs = inode->i_private;
 610
 611         if (ffs->state == FFS_CLOSING)
 612                 return -EBUSY;
 613
 614         file->private_data = ffs;
 615         ffs_data_opened(ffs);
 616
 617         return stream_open(inode, file);
 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         ffs_data_closed(ffs);
 625
 626         return 0;
 627 }
 628
 629 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 630 {
 631         struct ffs_data *ffs = file->private_data;
 632         struct usb_gadget *gadget = ffs->gadget;
 633         long ret;
 634
 635         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 636                 struct ffs_function *func = ffs->func;
 637                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 638         } else if (gadget && gadget->ops->ioctl) {
 639                 ret = gadget->ops->ioctl(gadget, code, value);
 640         } else {
 641                 ret = -ENOTTY;
 642         }
 643
 644         return ret;
 645 }
 646
 647 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 648 {
 649         struct ffs_data *ffs = file->private_data;
 650         __poll_t mask = EPOLLWRNORM;
 651         int ret;
 652
 653         poll_wait(file, &ffs->ev.waitq, wait);
 654
 655         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 656         if (ret < 0)
 657                 return mask;
 658
 659         switch (ffs->state) {
 660         case FFS_READ_DESCRIPTORS:
 661         case FFS_READ_STRINGS:
 662                 mask |= EPOLLOUT;
 663                 break;
 664
 665         case FFS_ACTIVE:
 666                 switch (ffs->setup_state) {
 667                 case FFS_NO_SETUP:
 668                         if (ffs->ev.count)
 669                                 mask |= EPOLLIN;
 670                         break;
 671
 672                 case FFS_SETUP_PENDING:
 673                 case FFS_SETUP_CANCELLED:
 674                         mask |= (EPOLLIN | EPOLLOUT);
 675                         break;
 676                 }
 677                 break;
 678
 679         case FFS_CLOSING:
 680                 break;
 681         case FFS_DEACTIVATED:
 682                 break;
 683         }
 684
 685         mutex_unlock(&ffs->mutex);
 686
 687         return mask;
 688 }
 689
 690 static const struct file_operations ffs_ep0_operations = {
 691         .llseek =       no_llseek,
 692
 693         .open =         ffs_ep0_open,
 694         .write =        ffs_ep0_write,
 695         .read =         ffs_ep0_read,
 696         .release =      ffs_ep0_release,
 697         .unlocked_ioctl =       ffs_ep0_ioctl,
 698         .poll =         ffs_ep0_poll,
 699 };
 700
 701
 702 /* "Normal" endpoints operations ********************************************/
 703
 704 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 705 {
 706         struct ffs_io_data *io_data = req->context;
 707
 708         if (req->status)
 709                 io_data->status = req->status;
 710         else
 711                 io_data->status = req->actual;
 712
 713         complete(&io_data->done);
 714 }
 715
 716 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 717 {
 718         ssize_t ret = copy_to_iter(data, data_len, iter);
 719         if (ret == data_len)
 720                 return ret;
 721
 722         if (iov_iter_count(iter))
 723                 return -EFAULT;
 724
 725         /*
 726          * Dear user space developer!
 727          *
 728          * TL;DR: To stop getting below error message in your kernel log, change
 729          * user space code using functionfs to align read buffers to a max
 730          * packet size.
 731          *
 732          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 733          * packet size.  When unaligned buffer is passed to functionfs, it
 734          * internally uses a larger, aligned buffer so that such UDCs are happy.
 735          *
 736          * Unfortunately, this means that host may send more data than was
 737          * requested in read(2) system call.  f_fs doesn’t know what to do with
 738          * that excess data so it simply drops it.
 739          *
 740          * Was the buffer aligned in the first place, no such problem would
 741          * happen.
 742          *
 743          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 744          * by splitting a request into multiple parts.  This splitting may still
 745          * be a problem though so it’s likely best to align the buffer
 746          * regardless of it being AIO or not..
 747          *
 748          * This only affects OUT endpoints, i.e. reading data with a read(2),
 749          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 750          * affected.
 751          */
 752         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 753                "Align read buffer size to max packet size to avoid the problem.\n",
 754                data_len, ret);
 755
 756         return ret;
 757 }
 758
 759 /*
 760  * allocate a virtually contiguous buffer and create a scatterlist describing it
 761  * @sg_table    - pointer to a place to be filled with sg_table contents
 762  * @size        - required buffer size
 763  */
 764 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 765 {
 766         struct page **pages;
 767         void *vaddr, *ptr;
 768         unsigned int n_pages;
 769         int i;
 770
 771         vaddr = vmalloc(sz);
 772         if (!vaddr)
 773                 return NULL;
 774
 775         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 776         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 777         if (!pages) {
 778                 vfree(vaddr);
 779
 780                 return NULL;
 781         }
 782         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 783                 pages[i] = vmalloc_to_page(ptr);
 784
 785         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 786                 kvfree(pages);
 787                 vfree(vaddr);
 788
 789                 return NULL;
 790         }
 791         kvfree(pages);
 792
 793         return vaddr;
 794 }
 795
 796 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 797         size_t data_len)
 798 {
 799         if (io_data->use_sg)
 800                 return ffs_build_sg_list(&io_data->sgt, data_len);
 801
 802         return kmalloc(data_len, GFP_KERNEL);
 803 }
 804
 805 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 806 {
 807         if (!io_data->buf)
 808                 return;
 809
 810         if (io_data->use_sg) {
 811                 sg_free_table(&io_data->sgt);
 812                 vfree(io_data->buf);
 813         } else {
 814                 kfree(io_data->buf);
 815         }
 816 }
 817
 818 static void ffs_user_copy_worker(struct work_struct *work)
 819 {
 820         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 821                                                    work);
 822         int ret = io_data->status;
 823         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 824
 825         if (io_data->read && ret > 0) {
 826                 kthread_use_mm(io_data->mm);
 827                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 828                 kthread_unuse_mm(io_data->mm);
 829         }
 830
 831         io_data->kiocb->ki_complete(io_data->kiocb, ret);
 832
 833         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 834                 eventfd_signal(io_data->ffs->ffs_eventfd);
 835
 836         if (io_data->read)
 837                 kfree(io_data->to_free);
 838         ffs_free_buffer(io_data);
 839         kfree(io_data);
 840 }
 841
 842 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 843                                          struct usb_request *req)
 844 {
 845         struct ffs_io_data *io_data = req->context;
 846         struct ffs_data *ffs = io_data->ffs;
 847
 848         io_data->status = req->status ? req->status : req->actual;
 849         usb_ep_free_request(_ep, req);
 850
 851         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 852         queue_work(ffs->io_completion_wq, &io_data->work);
 853 }
 854
 855 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 856 {
 857         /*
 858          * See comment in struct ffs_epfile for full read_buffer pointer
 859          * synchronisation story.
 860          */
 861         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 862         if (buf && buf != READ_BUFFER_DROP)
 863                 kfree(buf);
 864 }
 865
 866 /* Assumes epfile->mutex is held. */
 867 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 868                                           struct iov_iter *iter)
 869 {
 870         /*
 871          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 872          * the buffer while we are using it.  See comment in struct ffs_epfile
 873          * for full read_buffer pointer synchronisation story.
 874          */
 875         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 876         ssize_t ret;
 877         if (!buf || buf == READ_BUFFER_DROP)
 878                 return 0;
 879
 880         ret = copy_to_iter(buf->data, buf->length, iter);
 881         if (buf->length == ret) {
 882                 kfree(buf);
 883                 return ret;
 884         }
 885
 886         if (iov_iter_count(iter)) {
 887                 ret = -EFAULT;
 888         } else {
 889                 buf->length -= ret;
 890                 buf->data += ret;
 891         }
 892
 893         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 894                 kfree(buf);
 895
 896         return ret;
 897 }
 898
 899 /* Assumes epfile->mutex is held. */
 900 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 901                                       void *data, int data_len,
 902                                       struct iov_iter *iter)
 903 {
 904         struct ffs_buffer *buf;
 905
 906         ssize_t ret = copy_to_iter(data, data_len, iter);
 907         if (data_len == ret)
 908                 return ret;
 909
 910         if (iov_iter_count(iter))
 911                 return -EFAULT;
 912
 913         /* See ffs_copy_to_iter for more context. */
 914         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 915                 data_len, ret);
 916
 917         data_len -= ret;
 918         buf = kmalloc(struct_size(buf, storage, data_len), GFP_KERNEL);
 919         if (!buf)
 920                 return -ENOMEM;
 921         buf->length = data_len;
 922         buf->data = buf->storage;
 923         memcpy(buf->storage, data + ret, flex_array_size(buf, storage, data_len));
 924
 925         /*
 926          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 927          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 928          * in struct ffs_epfile for full read_buffer pointer synchronisation
 929          * story.
 930          */
 931         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 932                 kfree(buf);
 933
 934         return ret;
 935 }
 936
 937 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 938 {
 939         struct ffs_epfile *epfile = file->private_data;
 940         struct usb_request *req;
 941         struct ffs_ep *ep;
 942         char *data = NULL;
 943         ssize_t ret, data_len = -EINVAL;
 944         int halt;
 945
 946         /* Are we still active? */
 947         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 948                 return -ENODEV;
 949
 950         /* Wait for endpoint to be enabled */
 951         ep = epfile->ep;
 952         if (!ep) {
 953                 if (file->f_flags & O_NONBLOCK)
 954                         return -EAGAIN;
 955
 956                 ret = wait_event_interruptible(
 957                                 epfile->ffs->wait, (ep = epfile->ep));
 958                 if (ret)
 959                         return -EINTR;
 960         }
 961
 962         /* Do we halt? */
 963         halt = (!io_data->read == !epfile->in);
 964         if (halt && epfile->isoc)
 965                 return -EINVAL;
 966
 967         /* We will be using request and read_buffer */
 968         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 969         if (ret)
 970                 goto error;
 971
 972         /* Allocate & copy */
 973         if (!halt) {
 974                 struct usb_gadget *gadget;
 975
 976                 /*
 977                  * Do we have buffered data from previous partial read?  Check
 978                  * that for synchronous case only because we do not have
 979                  * facility to ‘wake up’ a pending asynchronous read and push
 980                  * buffered data to it which we would need to make things behave
 981                  * consistently.
 982                  */
 983                 if (!io_data->aio && io_data->read) {
 984                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 985                         if (ret)
 986                                 goto error_mutex;
 987                 }
 988
 989                 /*
 990                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 991                  * before the waiting completes, so do not assign to 'gadget'
 992                  * earlier
 993                  */
 994                 gadget = epfile->ffs->gadget;
 995
 996                 spin_lock_irq(&epfile->ffs->eps_lock);
 997                 /* In the meantime, endpoint got disabled or changed. */
 998                 if (epfile->ep != ep) {
 999                         ret = -ESHUTDOWN;
1000                         goto error_lock;
1001                 }
1002                 data_len = iov_iter_count(&io_data->data);
1003                 /*
1004                  * Controller may require buffer size to be aligned to
1005                  * maxpacketsize of an out endpoint.
1006                  */
1007                 if (io_data->read)
1008                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1009
1010                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1011                 spin_unlock_irq(&epfile->ffs->eps_lock);
1012
1013                 data = ffs_alloc_buffer(io_data, data_len);
1014                 if (!data) {
1015                         ret = -ENOMEM;
1016                         goto error_mutex;
1017                 }
1018                 if (!io_data->read &&
1019                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1020                         ret = -EFAULT;
1021                         goto error_mutex;
1022                 }
1023         }
1024
1025         spin_lock_irq(&epfile->ffs->eps_lock);
1026
1027         if (epfile->ep != ep) {
1028                 /* In the meantime, endpoint got disabled or changed. */
1029                 ret = -ESHUTDOWN;
1030         } else if (halt) {
1031                 ret = usb_ep_set_halt(ep->ep);
1032                 if (!ret)
1033                         ret = -EBADMSG;
1034         } else if (data_len == -EINVAL) {
1035                 /*
1036                  * Sanity Check: even though data_len can't be used
1037                  * uninitialized at the time I write this comment, some
1038                  * compilers complain about this situation.
1039                  * In order to keep the code clean from warnings, data_len is
1040                  * being initialized to -EINVAL during its declaration, which
1041                  * means we can't rely on compiler anymore to warn no future
1042                  * changes won't result in data_len being used uninitialized.
1043                  * For such reason, we're adding this redundant sanity check
1044                  * here.
1045                  */
1046                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1047                 ret = -EINVAL;
1048         } else if (!io_data->aio) {
1049                 bool interrupted = false;
1050
1051                 req = ep->req;
1052                 if (io_data->use_sg) {
1053                         req->buf = NULL;
1054                         req->sg = io_data->sgt.sgl;
1055                         req->num_sgs = io_data->sgt.nents;
1056                 } else {
1057                         req->buf = data;
1058                         req->num_sgs = 0;
1059                 }
1060                 req->length = data_len;
1061
1062                 io_data->buf = data;
1063
1064                 init_completion(&io_data->done);
1065                 req->context  = io_data;
1066                 req->complete = ffs_epfile_io_complete;
1067
1068                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1069                 if (ret < 0)
1070                         goto error_lock;
1071
1072                 spin_unlock_irq(&epfile->ffs->eps_lock);
1073
1074                 if (wait_for_completion_interruptible(&io_data->done)) {
1075                         spin_lock_irq(&epfile->ffs->eps_lock);
1076                         if (epfile->ep != ep) {
1077                                 ret = -ESHUTDOWN;
1078                                 goto error_lock;
1079                         }
1080                         /*
1081                          * To avoid race condition with ffs_epfile_io_complete,
1082                          * dequeue the request first then check
1083                          * status. usb_ep_dequeue API should guarantee no race
1084                          * condition with req->complete callback.
1085                          */
1086                         usb_ep_dequeue(ep->ep, req);
1087                         spin_unlock_irq(&epfile->ffs->eps_lock);
1088                         wait_for_completion(&io_data->done);
1089                         interrupted = io_data->status < 0;
1090                 }
1091
1092                 if (interrupted)
1093                         ret = -EINTR;
1094                 else if (io_data->read && io_data->status > 0)
1095                         ret = __ffs_epfile_read_data(epfile, data, io_data->status,
1096                                                      &io_data->data);
1097                 else
1098                         ret = io_data->status;
1099                 goto error_mutex;
1100         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1101                 ret = -ENOMEM;
1102         } else {
1103                 if (io_data->use_sg) {
1104                         req->buf = NULL;
1105                         req->sg = io_data->sgt.sgl;
1106                         req->num_sgs = io_data->sgt.nents;
1107                 } else {
1108                         req->buf = data;
1109                         req->num_sgs = 0;
1110                 }
1111                 req->length = data_len;
1112
1113                 io_data->buf = data;
1114                 io_data->ep = ep->ep;
1115                 io_data->req = req;
1116                 io_data->ffs = epfile->ffs;
1117
1118                 req->context  = io_data;
1119                 req->complete = ffs_epfile_async_io_complete;
1120
1121                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1122                 if (ret) {
1123                         io_data->req = NULL;
1124                         usb_ep_free_request(ep->ep, req);
1125                         goto error_lock;
1126                 }
1127
1128                 ret = -EIOCBQUEUED;
1129                 /*
1130                  * Do not kfree the buffer in this function.  It will be freed
1131                  * by ffs_user_copy_worker.
1132                  */
1133                 data = NULL;
1134         }
1135
1136 error_lock:
1137         spin_unlock_irq(&epfile->ffs->eps_lock);
1138 error_mutex:
1139         mutex_unlock(&epfile->mutex);
1140 error:
1141         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1142                 ffs_free_buffer(io_data);
1143         return ret;
1144 }
1145
1146 static int
1147 ffs_epfile_open(struct inode *inode, struct file *file)
1148 {
1149         struct ffs_epfile *epfile = inode->i_private;
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 stream_open(inode, file);
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         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1168
1169         if (io_data && io_data->ep && io_data->req)
1170                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1171         else
1172                 value = -EINVAL;
1173
1174         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1175
1176         return value;
1177 }
1178
1179 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1180 {
1181         struct ffs_io_data io_data, *p = &io_data;
1182         ssize_t res;
1183
1184         if (!is_sync_kiocb(kiocb)) {
1185                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1186                 if (!p)
1187                         return -ENOMEM;
1188                 p->aio = true;
1189         } else {
1190                 memset(p, 0, sizeof(*p));
1191                 p->aio = false;
1192         }
1193
1194         p->read = false;
1195         p->kiocb = kiocb;
1196         p->data = *from;
1197         p->mm = current->mm;
1198
1199         kiocb->private = p;
1200
1201         if (p->aio)
1202                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1203
1204         res = ffs_epfile_io(kiocb->ki_filp, p);
1205         if (res == -EIOCBQUEUED)
1206                 return res;
1207         if (p->aio)
1208                 kfree(p);
1209         else
1210                 *from = p->data;
1211         return res;
1212 }
1213
1214 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1215 {
1216         struct ffs_io_data io_data, *p = &io_data;
1217         ssize_t res;
1218
1219         if (!is_sync_kiocb(kiocb)) {
1220                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1221                 if (!p)
1222                         return -ENOMEM;
1223                 p->aio = true;
1224         } else {
1225                 memset(p, 0, sizeof(*p));
1226                 p->aio = false;
1227         }
1228
1229         p->read = true;
1230         p->kiocb = kiocb;
1231         if (p->aio) {
1232                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1233                 if (!iter_is_ubuf(&p->data) && !p->to_free) {
1234                         kfree(p);
1235                         return -ENOMEM;
1236                 }
1237         } else {
1238                 p->data = *to;
1239                 p->to_free = NULL;
1240         }
1241         p->mm = current->mm;
1242
1243         kiocb->private = p;
1244
1245         if (p->aio)
1246                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1247
1248         res = ffs_epfile_io(kiocb->ki_filp, p);
1249         if (res == -EIOCBQUEUED)
1250                 return res;
1251
1252         if (p->aio) {
1253                 kfree(p->to_free);
1254                 kfree(p);
1255         } else {
1256                 *to = p->data;
1257         }
1258         return res;
1259 }
1260
1261 static int
1262 ffs_epfile_release(struct inode *inode, struct file *file)
1263 {
1264         struct ffs_epfile *epfile = inode->i_private;
1265
1266         __ffs_epfile_read_buffer_free(epfile);
1267         ffs_data_closed(epfile->ffs);
1268
1269         return 0;
1270 }
1271
1272 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1273                              unsigned long value)
1274 {
1275         struct ffs_epfile *epfile = file->private_data;
1276         struct ffs_ep *ep;
1277         int ret;
1278
1279         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1280                 return -ENODEV;
1281
1282         /* Wait for endpoint to be enabled */
1283         ep = epfile->ep;
1284         if (!ep) {
1285                 if (file->f_flags & O_NONBLOCK)
1286                         return -EAGAIN;
1287
1288                 ret = wait_event_interruptible(
1289                                 epfile->ffs->wait, (ep = epfile->ep));
1290                 if (ret)
1291                         return -EINTR;
1292         }
1293
1294         spin_lock_irq(&epfile->ffs->eps_lock);
1295
1296         /* In the meantime, endpoint got disabled or changed. */
1297         if (epfile->ep != ep) {
1298                 spin_unlock_irq(&epfile->ffs->eps_lock);
1299                 return -ESHUTDOWN;
1300         }
1301
1302         switch (code) {
1303         case FUNCTIONFS_FIFO_STATUS:
1304                 ret = usb_ep_fifo_status(epfile->ep->ep);
1305                 break;
1306         case FUNCTIONFS_FIFO_FLUSH:
1307                 usb_ep_fifo_flush(epfile->ep->ep);
1308                 ret = 0;
1309                 break;
1310         case FUNCTIONFS_CLEAR_HALT:
1311                 ret = usb_ep_clear_halt(epfile->ep->ep);
1312                 break;
1313         case FUNCTIONFS_ENDPOINT_REVMAP:
1314                 ret = epfile->ep->num;
1315                 break;
1316         case FUNCTIONFS_ENDPOINT_DESC:
1317         {
1318                 int desc_idx;
1319                 struct usb_endpoint_descriptor desc1, *desc;
1320
1321                 switch (epfile->ffs->gadget->speed) {
1322                 case USB_SPEED_SUPER:
1323                 case USB_SPEED_SUPER_PLUS:
1324                         desc_idx = 2;
1325                         break;
1326                 case USB_SPEED_HIGH:
1327                         desc_idx = 1;
1328                         break;
1329                 default:
1330                         desc_idx = 0;
1331                 }
1332
1333                 desc = epfile->ep->descs[desc_idx];
1334                 memcpy(&desc1, desc, desc->bLength);
1335
1336                 spin_unlock_irq(&epfile->ffs->eps_lock);
1337                 ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
1338                 if (ret)
1339                         ret = -EFAULT;
1340                 return ret;
1341         }
1342         default:
1343                 ret = -ENOTTY;
1344         }
1345         spin_unlock_irq(&epfile->ffs->eps_lock);
1346
1347         return ret;
1348 }
1349
1350 static const struct file_operations ffs_epfile_operations = {
1351         .llseek =       no_llseek,
1352
1353         .open =         ffs_epfile_open,
1354         .write_iter =   ffs_epfile_write_iter,
1355         .read_iter =    ffs_epfile_read_iter,
1356         .release =      ffs_epfile_release,
1357         .unlocked_ioctl =       ffs_epfile_ioctl,
1358         .compat_ioctl = compat_ptr_ioctl,
1359 };
1360
1361
1362 /* File system and super block operations ***********************************/
1363
1364 /*
1365  * Mounting the file system creates a controller file, used first for
1366  * function configuration then later for event monitoring.
1367  */
1368
1369 static struct inode *__must_check
1370 ffs_sb_make_inode(struct super_block *sb, void *data,
1371                   const struct file_operations *fops,
1372                   const struct inode_operations *iops,
1373                   struct ffs_file_perms *perms)
1374 {
1375         struct inode *inode;
1376
1377         inode = new_inode(sb);
1378
1379         if (inode) {
1380                 struct timespec64 ts = inode_set_ctime_current(inode);
1381
1382                 inode->i_ino     = get_next_ino();
1383                 inode->i_mode    = perms->mode;
1384                 inode->i_uid     = perms->uid;
1385                 inode->i_gid     = perms->gid;
1386                 inode_set_atime_to_ts(inode, ts);
1387                 inode_set_mtime_to_ts(inode, ts);
1388                 inode->i_private = data;
1389                 if (fops)
1390                         inode->i_fop = fops;
1391                 if (iops)
1392                         inode->i_op  = iops;
1393         }
1394
1395         return inode;
1396 }
1397
1398 /* Create "regular" file */
1399 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1400                                         const char *name, void *data,
1401                                         const struct file_operations *fops)
1402 {
1403         struct ffs_data *ffs = sb->s_fs_info;
1404         struct dentry   *dentry;
1405         struct inode    *inode;
1406
1407         dentry = d_alloc_name(sb->s_root, name);
1408         if (!dentry)
1409                 return NULL;
1410
1411         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1412         if (!inode) {
1413                 dput(dentry);
1414                 return NULL;
1415         }
1416
1417         d_add(dentry, inode);
1418         return dentry;
1419 }
1420
1421 /* Super block */
1422 static const struct super_operations ffs_sb_operations = {
1423         .statfs =       simple_statfs,
1424         .drop_inode =   generic_delete_inode,
1425 };
1426
1427 struct ffs_sb_fill_data {
1428         struct ffs_file_perms perms;
1429         umode_t root_mode;
1430         const char *dev_name;
1431         bool no_disconnect;
1432         struct ffs_data *ffs_data;
1433 };
1434
1435 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1436 {
1437         struct ffs_sb_fill_data *data = fc->fs_private;
1438         struct inode    *inode;
1439         struct ffs_data *ffs = data->ffs_data;
1440
1441         ffs->sb              = sb;
1442         data->ffs_data       = NULL;
1443         sb->s_fs_info        = ffs;
1444         sb->s_blocksize      = PAGE_SIZE;
1445         sb->s_blocksize_bits = PAGE_SHIFT;
1446         sb->s_magic          = FUNCTIONFS_MAGIC;
1447         sb->s_op             = &ffs_sb_operations;
1448         sb->s_time_gran      = 1;
1449
1450         /* Root inode */
1451         data->perms.mode = data->root_mode;
1452         inode = ffs_sb_make_inode(sb, NULL,
1453                                   &simple_dir_operations,
1454                                   &simple_dir_inode_operations,
1455                                   &data->perms);
1456         sb->s_root = d_make_root(inode);
1457         if (!sb->s_root)
1458                 return -ENOMEM;
1459
1460         /* EP0 file */
1461         if (!ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations))
1462                 return -ENOMEM;
1463
1464         return 0;
1465 }
1466
1467 enum {
1468         Opt_no_disconnect,
1469         Opt_rmode,
1470         Opt_fmode,
1471         Opt_mode,
1472         Opt_uid,
1473         Opt_gid,
1474 };
1475
1476 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1477         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1478         fsparam_u32     ("rmode",               Opt_rmode),
1479         fsparam_u32     ("fmode",               Opt_fmode),
1480         fsparam_u32     ("mode",                Opt_mode),
1481         fsparam_u32     ("uid",                 Opt_uid),
1482         fsparam_u32     ("gid",                 Opt_gid),
1483         {}
1484 };
1485
1486 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1487 {
1488         struct ffs_sb_fill_data *data = fc->fs_private;
1489         struct fs_parse_result result;
1490         int opt;
1491
1492         opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1493         if (opt < 0)
1494                 return opt;
1495
1496         switch (opt) {
1497         case Opt_no_disconnect:
1498                 data->no_disconnect = result.boolean;
1499                 break;
1500         case Opt_rmode:
1501                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1502                 break;
1503         case Opt_fmode:
1504                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1505                 break;
1506         case Opt_mode:
1507                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1508                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1509                 break;
1510
1511         case Opt_uid:
1512                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1513                 if (!uid_valid(data->perms.uid))
1514                         goto unmapped_value;
1515                 break;
1516         case Opt_gid:
1517                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1518                 if (!gid_valid(data->perms.gid))
1519                         goto unmapped_value;
1520                 break;
1521
1522         default:
1523                 return -ENOPARAM;
1524         }
1525
1526         return 0;
1527
1528 unmapped_value:
1529         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1530 }
1531
1532 /*
1533  * Set up the superblock for a mount.
1534  */
1535 static int ffs_fs_get_tree(struct fs_context *fc)
1536 {
1537         struct ffs_sb_fill_data *ctx = fc->fs_private;
1538         struct ffs_data *ffs;
1539         int ret;
1540
1541         if (!fc->source)
1542                 return invalf(fc, "No source specified");
1543
1544         ffs = ffs_data_new(fc->source);
1545         if (!ffs)
1546                 return -ENOMEM;
1547         ffs->file_perms = ctx->perms;
1548         ffs->no_disconnect = ctx->no_disconnect;
1549
1550         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1551         if (!ffs->dev_name) {
1552                 ffs_data_put(ffs);
1553                 return -ENOMEM;
1554         }
1555
1556         ret = ffs_acquire_dev(ffs->dev_name, ffs);
1557         if (ret) {
1558                 ffs_data_put(ffs);
1559                 return ret;
1560         }
1561
1562         ctx->ffs_data = ffs;
1563         return get_tree_nodev(fc, ffs_sb_fill);
1564 }
1565
1566 static void ffs_fs_free_fc(struct fs_context *fc)
1567 {
1568         struct ffs_sb_fill_data *ctx = fc->fs_private;
1569
1570         if (ctx) {
1571                 if (ctx->ffs_data) {
1572                         ffs_data_put(ctx->ffs_data);
1573                 }
1574
1575                 kfree(ctx);
1576         }
1577 }
1578
1579 static const struct fs_context_operations ffs_fs_context_ops = {
1580         .free           = ffs_fs_free_fc,
1581         .parse_param    = ffs_fs_parse_param,
1582         .get_tree       = ffs_fs_get_tree,
1583 };
1584
1585 static int ffs_fs_init_fs_context(struct fs_context *fc)
1586 {
1587         struct ffs_sb_fill_data *ctx;
1588
1589         ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1590         if (!ctx)
1591                 return -ENOMEM;
1592
1593         ctx->perms.mode = S_IFREG | 0600;
1594         ctx->perms.uid = GLOBAL_ROOT_UID;
1595         ctx->perms.gid = GLOBAL_ROOT_GID;
1596         ctx->root_mode = S_IFDIR | 0500;
1597         ctx->no_disconnect = false;
1598
1599         fc->fs_private = ctx;
1600         fc->ops = &ffs_fs_context_ops;
1601         return 0;
1602 }
1603
1604 static void
1605 ffs_fs_kill_sb(struct super_block *sb)
1606 {
1607         kill_litter_super(sb);
1608         if (sb->s_fs_info)
1609                 ffs_data_closed(sb->s_fs_info);
1610 }
1611
1612 static struct file_system_type ffs_fs_type = {
1613         .owner          = THIS_MODULE,
1614         .name           = "functionfs",
1615         .init_fs_context = ffs_fs_init_fs_context,
1616         .parameters     = ffs_fs_fs_parameters,
1617         .kill_sb        = ffs_fs_kill_sb,
1618 };
1619 MODULE_ALIAS_FS("functionfs");
1620
1621
1622 /* Driver's main init/cleanup functions *************************************/
1623
1624 static int functionfs_init(void)
1625 {
1626         int ret;
1627
1628         ret = register_filesystem(&ffs_fs_type);
1629         if (!ret)
1630                 pr_info("file system registered\n");
1631         else
1632                 pr_err("failed registering file system (%d)\n", ret);
1633
1634         return ret;
1635 }
1636
1637 static void functionfs_cleanup(void)
1638 {
1639         pr_info("unloading\n");
1640         unregister_filesystem(&ffs_fs_type);
1641 }
1642
1643
1644 /* ffs_data and ffs_function construction and destruction code **************/
1645
1646 static void ffs_data_clear(struct ffs_data *ffs);
1647 static void ffs_data_reset(struct ffs_data *ffs);
1648
1649 static void ffs_data_get(struct ffs_data *ffs)
1650 {
1651         refcount_inc(&ffs->ref);
1652 }
1653
1654 static void ffs_data_opened(struct ffs_data *ffs)
1655 {
1656         refcount_inc(&ffs->ref);
1657         if (atomic_add_return(1, &ffs->opened) == 1 &&
1658                         ffs->state == FFS_DEACTIVATED) {
1659                 ffs->state = FFS_CLOSING;
1660                 ffs_data_reset(ffs);
1661         }
1662 }
1663
1664 static void ffs_data_put(struct ffs_data *ffs)
1665 {
1666         if (refcount_dec_and_test(&ffs->ref)) {
1667                 pr_info("%s(): freeing\n", __func__);
1668                 ffs_data_clear(ffs);
1669                 ffs_release_dev(ffs->private_data);
1670                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1671                        swait_active(&ffs->ep0req_completion.wait) ||
1672                        waitqueue_active(&ffs->wait));
1673                 destroy_workqueue(ffs->io_completion_wq);
1674                 kfree(ffs->dev_name);
1675                 kfree(ffs);
1676         }
1677 }
1678
1679 static void ffs_data_closed(struct ffs_data *ffs)
1680 {
1681         struct ffs_epfile *epfiles;
1682         unsigned long flags;
1683
1684         if (atomic_dec_and_test(&ffs->opened)) {
1685                 if (ffs->no_disconnect) {
1686                         ffs->state = FFS_DEACTIVATED;
1687                         spin_lock_irqsave(&ffs->eps_lock, flags);
1688                         epfiles = ffs->epfiles;
1689                         ffs->epfiles = NULL;
1690                         spin_unlock_irqrestore(&ffs->eps_lock,
1691                                                         flags);
1692
1693                         if (epfiles)
1694                                 ffs_epfiles_destroy(epfiles,
1695                                                  ffs->eps_count);
1696
1697                         if (ffs->setup_state == FFS_SETUP_PENDING)
1698                                 __ffs_ep0_stall(ffs);
1699                 } else {
1700                         ffs->state = FFS_CLOSING;
1701                         ffs_data_reset(ffs);
1702                 }
1703         }
1704         if (atomic_read(&ffs->opened) < 0) {
1705                 ffs->state = FFS_CLOSING;
1706                 ffs_data_reset(ffs);
1707         }
1708
1709         ffs_data_put(ffs);
1710 }
1711
1712 static struct ffs_data *ffs_data_new(const char *dev_name)
1713 {
1714         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1715         if (!ffs)
1716                 return NULL;
1717
1718         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1719         if (!ffs->io_completion_wq) {
1720                 kfree(ffs);
1721                 return NULL;
1722         }
1723
1724         refcount_set(&ffs->ref, 1);
1725         atomic_set(&ffs->opened, 0);
1726         ffs->state = FFS_READ_DESCRIPTORS;
1727         mutex_init(&ffs->mutex);
1728         spin_lock_init(&ffs->eps_lock);
1729         init_waitqueue_head(&ffs->ev.waitq);
1730         init_waitqueue_head(&ffs->wait);
1731         init_completion(&ffs->ep0req_completion);
1732
1733         /* XXX REVISIT need to update it in some places, or do we? */
1734         ffs->ev.can_stall = 1;
1735
1736         return ffs;
1737 }
1738
1739 static void ffs_data_clear(struct ffs_data *ffs)
1740 {
1741         struct ffs_epfile *epfiles;
1742         unsigned long flags;
1743
1744         ffs_closed(ffs);
1745
1746         BUG_ON(ffs->gadget);
1747
1748         spin_lock_irqsave(&ffs->eps_lock, flags);
1749         epfiles = ffs->epfiles;
1750         ffs->epfiles = NULL;
1751         spin_unlock_irqrestore(&ffs->eps_lock, flags);
1752
1753         /*
1754          * potential race possible between ffs_func_eps_disable
1755          * & ffs_epfile_release therefore maintaining a local
1756          * copy of epfile will save us from use-after-free.
1757          */
1758         if (epfiles) {
1759                 ffs_epfiles_destroy(epfiles, ffs->eps_count);
1760                 ffs->epfiles = NULL;
1761         }
1762
1763         if (ffs->ffs_eventfd) {
1764                 eventfd_ctx_put(ffs->ffs_eventfd);
1765                 ffs->ffs_eventfd = NULL;
1766         }
1767
1768         kfree(ffs->raw_descs_data);
1769         kfree(ffs->raw_strings);
1770         kfree(ffs->stringtabs);
1771 }
1772
1773 static void ffs_data_reset(struct ffs_data *ffs)
1774 {
1775         ffs_data_clear(ffs);
1776
1777         ffs->raw_descs_data = NULL;
1778         ffs->raw_descs = NULL;
1779         ffs->raw_strings = NULL;
1780         ffs->stringtabs = NULL;
1781
1782         ffs->raw_descs_length = 0;
1783         ffs->fs_descs_count = 0;
1784         ffs->hs_descs_count = 0;
1785         ffs->ss_descs_count = 0;
1786
1787         ffs->strings_count = 0;
1788         ffs->interfaces_count = 0;
1789         ffs->eps_count = 0;
1790
1791         ffs->ev.count = 0;
1792
1793         ffs->state = FFS_READ_DESCRIPTORS;
1794         ffs->setup_state = FFS_NO_SETUP;
1795         ffs->flags = 0;
1796
1797         ffs->ms_os_descs_ext_prop_count = 0;
1798         ffs->ms_os_descs_ext_prop_name_len = 0;
1799         ffs->ms_os_descs_ext_prop_data_len = 0;
1800 }
1801
1802
1803 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1804 {
1805         struct usb_gadget_strings **lang;
1806         int first_id;
1807
1808         if (WARN_ON(ffs->state != FFS_ACTIVE
1809                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1810                 return -EBADFD;
1811
1812         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1813         if (first_id < 0)
1814                 return first_id;
1815
1816         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1817         if (!ffs->ep0req)
1818                 return -ENOMEM;
1819         ffs->ep0req->complete = ffs_ep0_complete;
1820         ffs->ep0req->context = ffs;
1821
1822         lang = ffs->stringtabs;
1823         if (lang) {
1824                 for (; *lang; ++lang) {
1825                         struct usb_string *str = (*lang)->strings;
1826                         int id = first_id;
1827                         for (; str->s; ++id, ++str)
1828                                 str->id = id;
1829                 }
1830         }
1831
1832         ffs->gadget = cdev->gadget;
1833         ffs_data_get(ffs);
1834         return 0;
1835 }
1836
1837 static void functionfs_unbind(struct ffs_data *ffs)
1838 {
1839         if (!WARN_ON(!ffs->gadget)) {
1840                 /* dequeue before freeing ep0req */
1841                 usb_ep_dequeue(ffs->gadget->ep0, ffs->ep0req);
1842                 mutex_lock(&ffs->mutex);
1843                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1844                 ffs->ep0req = NULL;
1845                 ffs->gadget = NULL;
1846                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1847                 mutex_unlock(&ffs->mutex);
1848                 ffs_data_put(ffs);
1849         }
1850 }
1851
1852 static int ffs_epfiles_create(struct ffs_data *ffs)
1853 {
1854         struct ffs_epfile *epfile, *epfiles;
1855         unsigned i, count;
1856
1857         count = ffs->eps_count;
1858         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1859         if (!epfiles)
1860                 return -ENOMEM;
1861
1862         epfile = epfiles;
1863         for (i = 1; i <= count; ++i, ++epfile) {
1864                 epfile->ffs = ffs;
1865                 mutex_init(&epfile->mutex);
1866                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1867                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1868                 else
1869                         sprintf(epfile->name, "ep%u", i);
1870                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1871                                                  epfile,
1872                                                  &ffs_epfile_operations);
1873                 if (!epfile->dentry) {
1874                         ffs_epfiles_destroy(epfiles, i - 1);
1875                         return -ENOMEM;
1876                 }
1877         }
1878
1879         ffs->epfiles = epfiles;
1880         return 0;
1881 }
1882
1883 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1884 {
1885         struct ffs_epfile *epfile = epfiles;
1886
1887         for (; count; --count, ++epfile) {
1888                 BUG_ON(mutex_is_locked(&epfile->mutex));
1889                 if (epfile->dentry) {
1890                         d_delete(epfile->dentry);
1891                         dput(epfile->dentry);
1892                         epfile->dentry = NULL;
1893                 }
1894         }
1895
1896         kfree(epfiles);
1897 }
1898
1899 static void ffs_func_eps_disable(struct ffs_function *func)
1900 {
1901         struct ffs_ep *ep;
1902         struct ffs_epfile *epfile;
1903         unsigned short count;
1904         unsigned long flags;
1905
1906         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1907         count = func->ffs->eps_count;
1908         epfile = func->ffs->epfiles;
1909         ep = func->eps;
1910         while (count--) {
1911                 /* pending requests get nuked */
1912                 if (ep->ep)
1913                         usb_ep_disable(ep->ep);
1914                 ++ep;
1915
1916                 if (epfile) {
1917                         epfile->ep = NULL;
1918                         __ffs_epfile_read_buffer_free(epfile);
1919                         ++epfile;
1920                 }
1921         }
1922         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1923 }
1924
1925 static int ffs_func_eps_enable(struct ffs_function *func)
1926 {
1927         struct ffs_data *ffs;
1928         struct ffs_ep *ep;
1929         struct ffs_epfile *epfile;
1930         unsigned short count;
1931         unsigned long flags;
1932         int ret = 0;
1933
1934         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1935         ffs = func->ffs;
1936         ep = func->eps;
1937         epfile = ffs->epfiles;
1938         count = ffs->eps_count;
1939         while(count--) {
1940                 ep->ep->driver_data = ep;
1941
1942                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1943                 if (ret) {
1944                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1945                                         __func__, ep->ep->name, ret);
1946                         break;
1947                 }
1948
1949                 ret = usb_ep_enable(ep->ep);
1950                 if (!ret) {
1951                         epfile->ep = ep;
1952                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1953                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1954                 } else {
1955                         break;
1956                 }
1957
1958                 ++ep;
1959                 ++epfile;
1960         }
1961
1962         wake_up_interruptible(&ffs->wait);
1963         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1964
1965         return ret;
1966 }
1967
1968
1969 /* Parsing and building descriptors and strings *****************************/
1970
1971 /*
1972  * This validates if data pointed by data is a valid USB descriptor as
1973  * well as record how many interfaces, endpoints and strings are
1974  * required by given configuration.  Returns address after the
1975  * descriptor or NULL if data is invalid.
1976  */
1977
1978 enum ffs_entity_type {
1979         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1980 };
1981
1982 enum ffs_os_desc_type {
1983         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1984 };
1985
1986 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1987                                    u8 *valuep,
1988                                    struct usb_descriptor_header *desc,
1989                                    void *priv);
1990
1991 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1992                                     struct usb_os_desc_header *h, void *data,
1993                                     unsigned len, void *priv);
1994
1995 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1996                                            ffs_entity_callback entity,
1997                                            void *priv, int *current_class)
1998 {
1999         struct usb_descriptor_header *_ds = (void *)data;
2000         u8 length;
2001         int ret;
2002
2003         /* At least two bytes are required: length and type */
2004         if (len < 2) {
2005                 pr_vdebug("descriptor too short\n");
2006                 return -EINVAL;
2007         }
2008
2009         /* If we have at least as many bytes as the descriptor takes? */
2010         length = _ds->bLength;
2011         if (len < length) {
2012                 pr_vdebug("descriptor longer then available data\n");
2013                 return -EINVAL;
2014         }
2015
2016 #define __entity_check_INTERFACE(val)  1
2017 #define __entity_check_STRING(val)     (val)
2018 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2019 #define __entity(type, val) do {                                        \
2020                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2021                 if (!__entity_check_ ##type(val)) {                     \
2022                         pr_vdebug("invalid entity's value\n");          \
2023                         return -EINVAL;                                 \
2024                 }                                                       \
2025                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2026                 if (ret < 0) {                                          \
2027                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2028                                  (val), ret);                           \
2029                         return ret;                                     \
2030                 }                                                       \
2031         } while (0)
2032
2033         /* Parse descriptor depending on type. */
2034         switch (_ds->bDescriptorType) {
2035         case USB_DT_DEVICE:
2036         case USB_DT_CONFIG:
2037         case USB_DT_STRING:
2038         case USB_DT_DEVICE_QUALIFIER:
2039                 /* function can't have any of those */
2040                 pr_vdebug("descriptor reserved for gadget: %d\n",
2041                       _ds->bDescriptorType);
2042                 return -EINVAL;
2043
2044         case USB_DT_INTERFACE: {
2045                 struct usb_interface_descriptor *ds = (void *)_ds;
2046                 pr_vdebug("interface descriptor\n");
2047                 if (length != sizeof *ds)
2048                         goto inv_length;
2049
2050                 __entity(INTERFACE, ds->bInterfaceNumber);
2051                 if (ds->iInterface)
2052                         __entity(STRING, ds->iInterface);
2053                 *current_class = ds->bInterfaceClass;
2054         }
2055                 break;
2056
2057         case USB_DT_ENDPOINT: {
2058                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2059                 pr_vdebug("endpoint descriptor\n");
2060                 if (length != USB_DT_ENDPOINT_SIZE &&
2061                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2062                         goto inv_length;
2063                 __entity(ENDPOINT, ds->bEndpointAddress);
2064         }
2065                 break;
2066
2067         case USB_TYPE_CLASS | 0x01:
2068                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2069                         pr_vdebug("hid descriptor\n");
2070                         if (length != sizeof(struct hid_descriptor))
2071                                 goto inv_length;
2072                         break;
2073                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2074                         pr_vdebug("ccid descriptor\n");
2075                         if (length != sizeof(struct ccid_descriptor))
2076                                 goto inv_length;
2077                         break;
2078                 } else {
2079                         pr_vdebug("unknown descriptor: %d for class %d\n",
2080                               _ds->bDescriptorType, *current_class);
2081                         return -EINVAL;
2082                 }
2083
2084         case USB_DT_OTG:
2085                 if (length != sizeof(struct usb_otg_descriptor))
2086                         goto inv_length;
2087                 break;
2088
2089         case USB_DT_INTERFACE_ASSOCIATION: {
2090                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2091                 pr_vdebug("interface association descriptor\n");
2092                 if (length != sizeof *ds)
2093                         goto inv_length;
2094                 if (ds->iFunction)
2095                         __entity(STRING, ds->iFunction);
2096         }
2097                 break;
2098
2099         case USB_DT_SS_ENDPOINT_COMP:
2100                 pr_vdebug("EP SS companion descriptor\n");
2101                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2102                         goto inv_length;
2103                 break;
2104
2105         case USB_DT_OTHER_SPEED_CONFIG:
2106         case USB_DT_INTERFACE_POWER:
2107         case USB_DT_DEBUG:
2108         case USB_DT_SECURITY:
2109         case USB_DT_CS_RADIO_CONTROL:
2110                 /* TODO */
2111                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2112                 return -EINVAL;
2113
2114         default:
2115                 /* We should never be here */
2116                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2117                 return -EINVAL;
2118
2119 inv_length:
2120                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2121                           _ds->bLength, _ds->bDescriptorType);
2122                 return -EINVAL;
2123         }
2124
2125 #undef __entity
2126 #undef __entity_check_DESCRIPTOR
2127 #undef __entity_check_INTERFACE
2128 #undef __entity_check_STRING
2129 #undef __entity_check_ENDPOINT
2130
2131         return length;
2132 }
2133
2134 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2135                                      ffs_entity_callback entity, void *priv)
2136 {
2137         const unsigned _len = len;
2138         unsigned long num = 0;
2139         int current_class = -1;
2140
2141         for (;;) {
2142                 int ret;
2143
2144                 if (num == count)
2145                         data = NULL;
2146
2147                 /* Record "descriptor" entity */
2148                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2149                 if (ret < 0) {
2150                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2151                                  num, ret);
2152                         return ret;
2153                 }
2154
2155                 if (!data)
2156                         return _len - len;
2157
2158                 ret = ffs_do_single_desc(data, len, entity, priv,
2159                         &current_class);
2160                 if (ret < 0) {
2161                         pr_debug("%s returns %d\n", __func__, ret);
2162                         return ret;
2163                 }
2164
2165                 len -= ret;
2166                 data += ret;
2167                 ++num;
2168         }
2169 }
2170
2171 static int __ffs_data_do_entity(enum ffs_entity_type type,
2172                                 u8 *valuep, struct usb_descriptor_header *desc,
2173                                 void *priv)
2174 {
2175         struct ffs_desc_helper *helper = priv;
2176         struct usb_endpoint_descriptor *d;
2177
2178         switch (type) {
2179         case FFS_DESCRIPTOR:
2180                 break;
2181
2182         case FFS_INTERFACE:
2183                 /*
2184                  * Interfaces are indexed from zero so if we
2185                  * encountered interface "n" then there are at least
2186                  * "n+1" interfaces.
2187                  */
2188                 if (*valuep >= helper->interfaces_count)
2189                         helper->interfaces_count = *valuep + 1;
2190                 break;
2191
2192         case FFS_STRING:
2193                 /*
2194                  * Strings are indexed from 1 (0 is reserved
2195                  * for languages list)
2196                  */
2197                 if (*valuep > helper->ffs->strings_count)
2198                         helper->ffs->strings_count = *valuep;
2199                 break;
2200
2201         case FFS_ENDPOINT:
2202                 d = (void *)desc;
2203                 helper->eps_count++;
2204                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2205                         return -EINVAL;
2206                 /* Check if descriptors for any speed were already parsed */
2207                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2208                         helper->ffs->eps_addrmap[helper->eps_count] =
2209                                 d->bEndpointAddress;
2210                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2211                                 d->bEndpointAddress)
2212                         return -EINVAL;
2213                 break;
2214         }
2215
2216         return 0;
2217 }
2218
2219 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2220                                    struct usb_os_desc_header *desc)
2221 {
2222         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2223         u16 w_index = le16_to_cpu(desc->wIndex);
2224
2225         if (bcd_version == 0x1) {
2226                 pr_warn("bcdVersion must be 0x0100, stored in Little Endian order. "
2227                         "Userspace driver should be fixed, accepting 0x0001 for compatibility.\n");
2228         } else if (bcd_version != 0x100) {
2229                 pr_vdebug("unsupported os descriptors version: 0x%x\n",
2230                           bcd_version);
2231                 return -EINVAL;
2232         }
2233         switch (w_index) {
2234         case 0x4:
2235                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2236                 break;
2237         case 0x5:
2238                 *next_type = FFS_OS_DESC_EXT_PROP;
2239                 break;
2240         default:
2241                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2242                 return -EINVAL;
2243         }
2244
2245         return sizeof(*desc);
2246 }
2247
2248 /*
2249  * Process all extended compatibility/extended property descriptors
2250  * of a feature descriptor
2251  */
2252 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2253                                               enum ffs_os_desc_type type,
2254                                               u16 feature_count,
2255                                               ffs_os_desc_callback entity,
2256                                               void *priv,
2257                                               struct usb_os_desc_header *h)
2258 {
2259         int ret;
2260         const unsigned _len = len;
2261
2262         /* loop over all ext compat/ext prop descriptors */
2263         while (feature_count--) {
2264                 ret = entity(type, h, data, len, priv);
2265                 if (ret < 0) {
2266                         pr_debug("bad OS descriptor, type: %d\n", type);
2267                         return ret;
2268                 }
2269                 data += ret;
2270                 len -= ret;
2271         }
2272         return _len - len;
2273 }
2274
2275 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2276 static int __must_check ffs_do_os_descs(unsigned count,
2277                                         char *data, unsigned len,
2278                                         ffs_os_desc_callback entity, void *priv)
2279 {
2280         const unsigned _len = len;
2281         unsigned long num = 0;
2282
2283         for (num = 0; num < count; ++num) {
2284                 int ret;
2285                 enum ffs_os_desc_type type;
2286                 u16 feature_count;
2287                 struct usb_os_desc_header *desc = (void *)data;
2288
2289                 if (len < sizeof(*desc))
2290                         return -EINVAL;
2291
2292                 /*
2293                  * Record "descriptor" entity.
2294                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2295                  * Move the data pointer to the beginning of extended
2296                  * compatibilities proper or extended properties proper
2297                  * portions of the data
2298                  */
2299                 if (le32_to_cpu(desc->dwLength) > len)
2300                         return -EINVAL;
2301
2302                 ret = __ffs_do_os_desc_header(&type, desc);
2303                 if (ret < 0) {
2304                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2305                                  num, ret);
2306                         return ret;
2307                 }
2308                 /*
2309                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2310                  */
2311                 feature_count = le16_to_cpu(desc->wCount);
2312                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2313                     (feature_count > 255 || desc->Reserved))
2314                                 return -EINVAL;
2315                 len -= ret;
2316                 data += ret;
2317
2318                 /*
2319                  * Process all function/property descriptors
2320                  * of this Feature Descriptor
2321                  */
2322                 ret = ffs_do_single_os_desc(data, len, type,
2323                                             feature_count, entity, priv, desc);
2324                 if (ret < 0) {
2325                         pr_debug("%s returns %d\n", __func__, ret);
2326                         return ret;
2327                 }
2328
2329                 len -= ret;
2330                 data += ret;
2331         }
2332         return _len - len;
2333 }
2334
2335 /*
2336  * Validate contents of the buffer from userspace related to OS descriptors.
2337  */
2338 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2339                                  struct usb_os_desc_header *h, void *data,
2340                                  unsigned len, void *priv)
2341 {
2342         struct ffs_data *ffs = priv;
2343         u8 length;
2344
2345         switch (type) {
2346         case FFS_OS_DESC_EXT_COMPAT: {
2347                 struct usb_ext_compat_desc *d = data;
2348                 int i;
2349
2350                 if (len < sizeof(*d) ||
2351                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2352                         return -EINVAL;
2353                 if (d->Reserved1 != 1) {
2354                         /*
2355                          * According to the spec, Reserved1 must be set to 1
2356                          * but older kernels incorrectly rejected non-zero
2357                          * values.  We fix it here to avoid returning EINVAL
2358                          * in response to values we used to accept.
2359                          */
2360                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2361                         d->Reserved1 = 1;
2362                 }
2363                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2364                         if (d->Reserved2[i])
2365                                 return -EINVAL;
2366
2367                 length = sizeof(struct usb_ext_compat_desc);
2368         }
2369                 break;
2370         case FFS_OS_DESC_EXT_PROP: {
2371                 struct usb_ext_prop_desc *d = data;
2372                 u32 type, pdl;
2373                 u16 pnl;
2374
2375                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2376                         return -EINVAL;
2377                 length = le32_to_cpu(d->dwSize);
2378                 if (len < length)
2379                         return -EINVAL;
2380                 type = le32_to_cpu(d->dwPropertyDataType);
2381                 if (type < USB_EXT_PROP_UNICODE ||
2382                     type > USB_EXT_PROP_UNICODE_MULTI) {
2383                         pr_vdebug("unsupported os descriptor property type: %d",
2384                                   type);
2385                         return -EINVAL;
2386                 }
2387                 pnl = le16_to_cpu(d->wPropertyNameLength);
2388                 if (length < 14 + pnl) {
2389                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2390                                   length, pnl, type);
2391                         return -EINVAL;
2392                 }
2393                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2394                 if (length != 14 + pnl + pdl) {
2395                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2396                                   length, pnl, pdl, type);
2397                         return -EINVAL;
2398                 }
2399                 ++ffs->ms_os_descs_ext_prop_count;
2400                 /* property name reported to the host as "WCHAR"s */
2401                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2402                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2403         }
2404                 break;
2405         default:
2406                 pr_vdebug("unknown descriptor: %d\n", type);
2407                 return -EINVAL;
2408         }
2409         return length;
2410 }
2411
2412 static int __ffs_data_got_descs(struct ffs_data *ffs,
2413                                 char *const _data, size_t len)
2414 {
2415         char *data = _data, *raw_descs;
2416         unsigned os_descs_count = 0, counts[3], flags;
2417         int ret = -EINVAL, i;
2418         struct ffs_desc_helper helper;
2419
2420         if (get_unaligned_le32(data + 4) != len)
2421                 goto error;
2422
2423         switch (get_unaligned_le32(data)) {
2424         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2425                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2426                 data += 8;
2427                 len  -= 8;
2428                 break;
2429         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2430                 flags = get_unaligned_le32(data + 8);
2431                 ffs->user_flags = flags;
2432                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2433                               FUNCTIONFS_HAS_HS_DESC |
2434                               FUNCTIONFS_HAS_SS_DESC |
2435                               FUNCTIONFS_HAS_MS_OS_DESC |
2436                               FUNCTIONFS_VIRTUAL_ADDR |
2437                               FUNCTIONFS_EVENTFD |
2438                               FUNCTIONFS_ALL_CTRL_RECIP |
2439                               FUNCTIONFS_CONFIG0_SETUP)) {
2440                         ret = -ENOSYS;
2441                         goto error;
2442                 }
2443                 data += 12;
2444                 len  -= 12;
2445                 break;
2446         default:
2447                 goto error;
2448         }
2449
2450         if (flags & FUNCTIONFS_EVENTFD) {
2451                 if (len < 4)
2452                         goto error;
2453                 ffs->ffs_eventfd =
2454                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2455                 if (IS_ERR(ffs->ffs_eventfd)) {
2456                         ret = PTR_ERR(ffs->ffs_eventfd);
2457                         ffs->ffs_eventfd = NULL;
2458                         goto error;
2459                 }
2460                 data += 4;
2461                 len  -= 4;
2462         }
2463
2464         /* Read fs_count, hs_count and ss_count (if present) */
2465         for (i = 0; i < 3; ++i) {
2466                 if (!(flags & (1 << i))) {
2467                         counts[i] = 0;
2468                 } else if (len < 4) {
2469                         goto error;
2470                 } else {
2471                         counts[i] = get_unaligned_le32(data);
2472                         data += 4;
2473                         len  -= 4;
2474                 }
2475         }
2476         if (flags & (1 << i)) {
2477                 if (len < 4) {
2478                         goto error;
2479                 }
2480                 os_descs_count = get_unaligned_le32(data);
2481                 data += 4;
2482                 len -= 4;
2483         }
2484
2485         /* Read descriptors */
2486         raw_descs = data;
2487         helper.ffs = ffs;
2488         for (i = 0; i < 3; ++i) {
2489                 if (!counts[i])
2490                         continue;
2491                 helper.interfaces_count = 0;
2492                 helper.eps_count = 0;
2493                 ret = ffs_do_descs(counts[i], data, len,
2494                                    __ffs_data_do_entity, &helper);
2495                 if (ret < 0)
2496                         goto error;
2497                 if (!ffs->eps_count && !ffs->interfaces_count) {
2498                         ffs->eps_count = helper.eps_count;
2499                         ffs->interfaces_count = helper.interfaces_count;
2500                 } else {
2501                         if (ffs->eps_count != helper.eps_count) {
2502                                 ret = -EINVAL;
2503                                 goto error;
2504                         }
2505                         if (ffs->interfaces_count != helper.interfaces_count) {
2506                                 ret = -EINVAL;
2507                                 goto error;
2508                         }
2509                 }
2510                 data += ret;
2511                 len  -= ret;
2512         }
2513         if (os_descs_count) {
2514                 ret = ffs_do_os_descs(os_descs_count, data, len,
2515                                       __ffs_data_do_os_desc, ffs);
2516                 if (ret < 0)
2517                         goto error;
2518                 data += ret;
2519                 len -= ret;
2520         }
2521
2522         if (raw_descs == data || len) {
2523                 ret = -EINVAL;
2524                 goto error;
2525         }
2526
2527         ffs->raw_descs_data     = _data;
2528         ffs->raw_descs          = raw_descs;
2529         ffs->raw_descs_length   = data - raw_descs;
2530         ffs->fs_descs_count     = counts[0];
2531         ffs->hs_descs_count     = counts[1];
2532         ffs->ss_descs_count     = counts[2];
2533         ffs->ms_os_descs_count  = os_descs_count;
2534
2535         return 0;
2536
2537 error:
2538         kfree(_data);
2539         return ret;
2540 }
2541
2542 static int __ffs_data_got_strings(struct ffs_data *ffs,
2543                                   char *const _data, size_t len)
2544 {
2545         u32 str_count, needed_count, lang_count;
2546         struct usb_gadget_strings **stringtabs, *t;
2547         const char *data = _data;
2548         struct usb_string *s;
2549
2550         if (len < 16 ||
2551             get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2552             get_unaligned_le32(data + 4) != len)
2553                 goto error;
2554         str_count  = get_unaligned_le32(data + 8);
2555         lang_count = get_unaligned_le32(data + 12);
2556
2557         /* if one is zero the other must be zero */
2558         if (!str_count != !lang_count)
2559                 goto error;
2560
2561         /* Do we have at least as many strings as descriptors need? */
2562         needed_count = ffs->strings_count;
2563         if (str_count < needed_count)
2564                 goto error;
2565
2566         /*
2567          * If we don't need any strings just return and free all
2568          * memory.
2569          */
2570         if (!needed_count) {
2571                 kfree(_data);
2572                 return 0;
2573         }
2574
2575         /* Allocate everything in one chunk so there's less maintenance. */
2576         {
2577                 unsigned i = 0;
2578                 vla_group(d);
2579                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2580                         size_add(lang_count, 1));
2581                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2582                 vla_item(d, struct usb_string, strings,
2583                         size_mul(lang_count, (needed_count + 1)));
2584
2585                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2586
2587                 if (!vlabuf) {
2588                         kfree(_data);
2589                         return -ENOMEM;
2590                 }
2591
2592                 /* Initialize the VLA pointers */
2593                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2594                 t = vla_ptr(vlabuf, d, stringtab);
2595                 i = lang_count;
2596                 do {
2597                         *stringtabs++ = t++;
2598                 } while (--i);
2599                 *stringtabs = NULL;
2600
2601                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2602                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2603                 t = vla_ptr(vlabuf, d, stringtab);
2604                 s = vla_ptr(vlabuf, d, strings);
2605         }
2606
2607         /* For each language */
2608         data += 16;
2609         len -= 16;
2610
2611         do { /* lang_count > 0 so we can use do-while */
2612                 unsigned needed = needed_count;
2613                 u32 str_per_lang = str_count;
2614
2615                 if (len < 3)
2616                         goto error_free;
2617                 t->language = get_unaligned_le16(data);
2618                 t->strings  = s;
2619                 ++t;
2620
2621                 data += 2;
2622                 len -= 2;
2623
2624                 /* For each string */
2625                 do { /* str_count > 0 so we can use do-while */
2626                         size_t length = strnlen(data, len);
2627
2628                         if (length == len)
2629                                 goto error_free;
2630
2631                         /*
2632                          * User may provide more strings then we need,
2633                          * if that's the case we simply ignore the
2634                          * rest
2635                          */
2636                         if (needed) {
2637                                 /*
2638                                  * s->id will be set while adding
2639                                  * function to configuration so for
2640                                  * now just leave garbage here.
2641                                  */
2642                                 s->s = data;
2643                                 --needed;
2644                                 ++s;
2645                         }
2646
2647                         data += length + 1;
2648                         len -= length + 1;
2649                 } while (--str_per_lang);
2650
2651                 s->id = 0;   /* terminator */
2652                 s->s = NULL;
2653                 ++s;
2654
2655         } while (--lang_count);
2656
2657         /* Some garbage left? */
2658         if (len)
2659                 goto error_free;
2660
2661         /* Done! */
2662         ffs->stringtabs = stringtabs;
2663         ffs->raw_strings = _data;
2664
2665         return 0;
2666
2667 error_free:
2668         kfree(stringtabs);
2669 error:
2670         kfree(_data);
2671         return -EINVAL;
2672 }
2673
2674
2675 /* Events handling and management *******************************************/
2676
2677 static void __ffs_event_add(struct ffs_data *ffs,
2678                             enum usb_functionfs_event_type type)
2679 {
2680         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2681         int neg = 0;
2682
2683         /*
2684          * Abort any unhandled setup
2685          *
2686          * We do not need to worry about some cmpxchg() changing value
2687          * of ffs->setup_state without holding the lock because when
2688          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2689          * the source does nothing.
2690          */
2691         if (ffs->setup_state == FFS_SETUP_PENDING)
2692                 ffs->setup_state = FFS_SETUP_CANCELLED;
2693
2694         /*
2695          * Logic of this function guarantees that there are at most four pending
2696          * evens on ffs->ev.types queue.  This is important because the queue
2697          * has space for four elements only and __ffs_ep0_read_events function
2698          * depends on that limit as well.  If more event types are added, those
2699          * limits have to be revisited or guaranteed to still hold.
2700          */
2701         switch (type) {
2702         case FUNCTIONFS_RESUME:
2703                 rem_type2 = FUNCTIONFS_SUSPEND;
2704                 fallthrough;
2705         case FUNCTIONFS_SUSPEND:
2706         case FUNCTIONFS_SETUP:
2707                 rem_type1 = type;
2708                 /* Discard all similar events */
2709                 break;
2710
2711         case FUNCTIONFS_BIND:
2712         case FUNCTIONFS_UNBIND:
2713         case FUNCTIONFS_DISABLE:
2714         case FUNCTIONFS_ENABLE:
2715                 /* Discard everything other then power management. */
2716                 rem_type1 = FUNCTIONFS_SUSPEND;
2717                 rem_type2 = FUNCTIONFS_RESUME;
2718                 neg = 1;
2719                 break;
2720
2721         default:
2722                 WARN(1, "%d: unknown event, this should not happen\n", type);
2723                 return;
2724         }
2725
2726         {
2727                 u8 *ev  = ffs->ev.types, *out = ev;
2728                 unsigned n = ffs->ev.count;
2729                 for (; n; --n, ++ev)
2730                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2731                                 *out++ = *ev;
2732                         else
2733                                 pr_vdebug("purging event %d\n", *ev);
2734                 ffs->ev.count = out - ffs->ev.types;
2735         }
2736
2737         pr_vdebug("adding event %d\n", type);
2738         ffs->ev.types[ffs->ev.count++] = type;
2739         wake_up_locked(&ffs->ev.waitq);
2740         if (ffs->ffs_eventfd)
2741                 eventfd_signal(ffs->ffs_eventfd);
2742 }
2743
2744 static void ffs_event_add(struct ffs_data *ffs,
2745                           enum usb_functionfs_event_type type)
2746 {
2747         unsigned long flags;
2748         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2749         __ffs_event_add(ffs, type);
2750         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2751 }
2752
2753 /* Bind/unbind USB function hooks *******************************************/
2754
2755 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2756 {
2757         int i;
2758
2759         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2760                 if (ffs->eps_addrmap[i] == endpoint_address)
2761                         return i;
2762         return -ENOENT;
2763 }
2764
2765 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2766                                     struct usb_descriptor_header *desc,
2767                                     void *priv)
2768 {
2769         struct usb_endpoint_descriptor *ds = (void *)desc;
2770         struct ffs_function *func = priv;
2771         struct ffs_ep *ffs_ep;
2772         unsigned ep_desc_id;
2773         int idx;
2774         static const char *speed_names[] = { "full", "high", "super" };
2775
2776         if (type != FFS_DESCRIPTOR)
2777                 return 0;
2778
2779         /*
2780          * If ss_descriptors is not NULL, we are reading super speed
2781          * descriptors; if hs_descriptors is not NULL, we are reading high
2782          * speed descriptors; otherwise, we are reading full speed
2783          * descriptors.
2784          */
2785         if (func->function.ss_descriptors) {
2786                 ep_desc_id = 2;
2787                 func->function.ss_descriptors[(long)valuep] = desc;
2788         } else if (func->function.hs_descriptors) {
2789                 ep_desc_id = 1;
2790                 func->function.hs_descriptors[(long)valuep] = desc;
2791         } else {
2792                 ep_desc_id = 0;
2793                 func->function.fs_descriptors[(long)valuep]    = desc;
2794         }
2795
2796         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2797                 return 0;
2798
2799         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2800         if (idx < 0)
2801                 return idx;
2802
2803         ffs_ep = func->eps + idx;
2804
2805         if (ffs_ep->descs[ep_desc_id]) {
2806                 pr_err("two %sspeed descriptors for EP %d\n",
2807                           speed_names[ep_desc_id],
2808                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2809                 return -EINVAL;
2810         }
2811         ffs_ep->descs[ep_desc_id] = ds;
2812
2813         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2814         if (ffs_ep->ep) {
2815                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2816                 if (!ds->wMaxPacketSize)
2817                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2818         } else {
2819                 struct usb_request *req;
2820                 struct usb_ep *ep;
2821                 u8 bEndpointAddress;
2822                 u16 wMaxPacketSize;
2823
2824                 /*
2825                  * We back up bEndpointAddress because autoconfig overwrites
2826                  * it with physical endpoint address.
2827                  */
2828                 bEndpointAddress = ds->bEndpointAddress;
2829                 /*
2830                  * We back up wMaxPacketSize because autoconfig treats
2831                  * endpoint descriptors as if they were full speed.
2832                  */
2833                 wMaxPacketSize = ds->wMaxPacketSize;
2834                 pr_vdebug("autoconfig\n");
2835                 ep = usb_ep_autoconfig(func->gadget, ds);
2836                 if (!ep)
2837                         return -ENOTSUPP;
2838                 ep->driver_data = func->eps + idx;
2839
2840                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2841                 if (!req)
2842                         return -ENOMEM;
2843
2844                 ffs_ep->ep  = ep;
2845                 ffs_ep->req = req;
2846                 func->eps_revmap[ds->bEndpointAddress &
2847                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2848                 /*
2849                  * If we use virtual address mapping, we restore
2850                  * original bEndpointAddress value.
2851                  */
2852                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2853                         ds->bEndpointAddress = bEndpointAddress;
2854                 /*
2855                  * Restore wMaxPacketSize which was potentially
2856                  * overwritten by autoconfig.
2857                  */
2858                 ds->wMaxPacketSize = wMaxPacketSize;
2859         }
2860         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2861
2862         return 0;
2863 }
2864
2865 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2866                                    struct usb_descriptor_header *desc,
2867                                    void *priv)
2868 {
2869         struct ffs_function *func = priv;
2870         unsigned idx;
2871         u8 newValue;
2872
2873         switch (type) {
2874         default:
2875         case FFS_DESCRIPTOR:
2876                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2877                 return 0;
2878
2879         case FFS_INTERFACE:
2880                 idx = *valuep;
2881                 if (func->interfaces_nums[idx] < 0) {
2882                         int id = usb_interface_id(func->conf, &func->function);
2883                         if (id < 0)
2884                                 return id;
2885                         func->interfaces_nums[idx] = id;
2886                 }
2887                 newValue = func->interfaces_nums[idx];
2888                 break;
2889
2890         case FFS_STRING:
2891                 /* String' IDs are allocated when fsf_data is bound to cdev */
2892                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2893                 break;
2894
2895         case FFS_ENDPOINT:
2896                 /*
2897                  * USB_DT_ENDPOINT are handled in
2898                  * __ffs_func_bind_do_descs().
2899                  */
2900                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2901                         return 0;
2902
2903                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2904                 if (!func->eps[idx].ep)
2905                         return -EINVAL;
2906
2907                 {
2908                         struct usb_endpoint_descriptor **descs;
2909                         descs = func->eps[idx].descs;
2910                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2911                 }
2912                 break;
2913         }
2914
2915         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2916         *valuep = newValue;
2917         return 0;
2918 }
2919
2920 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2921                                       struct usb_os_desc_header *h, void *data,
2922                                       unsigned len, void *priv)
2923 {
2924         struct ffs_function *func = priv;
2925         u8 length = 0;
2926
2927         switch (type) {
2928         case FFS_OS_DESC_EXT_COMPAT: {
2929                 struct usb_ext_compat_desc *desc = data;
2930                 struct usb_os_desc_table *t;
2931
2932                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2933                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2934                 memcpy(t->os_desc->ext_compat_id, &desc->IDs,
2935                        sizeof_field(struct usb_ext_compat_desc, IDs));
2936                 length = sizeof(*desc);
2937         }
2938                 break;
2939         case FFS_OS_DESC_EXT_PROP: {
2940                 struct usb_ext_prop_desc *desc = data;
2941                 struct usb_os_desc_table *t;
2942                 struct usb_os_desc_ext_prop *ext_prop;
2943                 char *ext_prop_name;
2944                 char *ext_prop_data;
2945
2946                 t = &func->function.os_desc_table[h->interface];
2947                 t->if_id = func->interfaces_nums[h->interface];
2948
2949                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2950                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2951
2952                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2953                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2954                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2955                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2956                 length = ext_prop->name_len + ext_prop->data_len + 14;
2957
2958                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2959                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2960                         ext_prop->name_len;
2961
2962                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2963                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2964                         ext_prop->data_len;
2965                 memcpy(ext_prop_data,
2966                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2967                        ext_prop->data_len);
2968                 /* unicode data reported to the host as "WCHAR"s */
2969                 switch (ext_prop->type) {
2970                 case USB_EXT_PROP_UNICODE:
2971                 case USB_EXT_PROP_UNICODE_ENV:
2972                 case USB_EXT_PROP_UNICODE_LINK:
2973                 case USB_EXT_PROP_UNICODE_MULTI:
2974                         ext_prop->data_len *= 2;
2975                         break;
2976                 }
2977                 ext_prop->data = ext_prop_data;
2978
2979                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2980                        ext_prop->name_len);
2981                 /* property name reported to the host as "WCHAR"s */
2982                 ext_prop->name_len *= 2;
2983                 ext_prop->name = ext_prop_name;
2984
2985                 t->os_desc->ext_prop_len +=
2986                         ext_prop->name_len + ext_prop->data_len + 14;
2987                 ++t->os_desc->ext_prop_count;
2988                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2989         }
2990                 break;
2991         default:
2992                 pr_vdebug("unknown descriptor: %d\n", type);
2993         }
2994
2995         return length;
2996 }
2997
2998 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2999                                                 struct usb_configuration *c)
3000 {
3001         struct ffs_function *func = ffs_func_from_usb(f);
3002         struct f_fs_opts *ffs_opts =
3003                 container_of(f->fi, struct f_fs_opts, func_inst);
3004         struct ffs_data *ffs_data;
3005         int ret;
3006
3007         /*
3008          * Legacy gadget triggers binding in functionfs_ready_callback,
3009          * which already uses locking; taking the same lock here would
3010          * cause a deadlock.
3011          *
3012          * Configfs-enabled gadgets however do need ffs_dev_lock.
3013          */
3014         if (!ffs_opts->no_configfs)
3015                 ffs_dev_lock();
3016         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3017         ffs_data = ffs_opts->dev->ffs_data;
3018         if (!ffs_opts->no_configfs)
3019                 ffs_dev_unlock();
3020         if (ret)
3021                 return ERR_PTR(ret);
3022
3023         func->ffs = ffs_data;
3024         func->conf = c;
3025         func->gadget = c->cdev->gadget;
3026
3027         /*
3028          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3029          * configurations are bound in sequence with list_for_each_entry,
3030          * in each configuration its functions are bound in sequence
3031          * with list_for_each_entry, so we assume no race condition
3032          * with regard to ffs_opts->bound access
3033          */
3034         if (!ffs_opts->refcnt) {
3035                 ret = functionfs_bind(func->ffs, c->cdev);
3036                 if (ret)
3037                         return ERR_PTR(ret);
3038         }
3039         ffs_opts->refcnt++;
3040         func->function.strings = func->ffs->stringtabs;
3041
3042         return ffs_opts;
3043 }
3044
3045 static int _ffs_func_bind(struct usb_configuration *c,
3046                           struct usb_function *f)
3047 {
3048         struct ffs_function *func = ffs_func_from_usb(f);
3049         struct ffs_data *ffs = func->ffs;
3050
3051         const int full = !!func->ffs->fs_descs_count;
3052         const int high = !!func->ffs->hs_descs_count;
3053         const int super = !!func->ffs->ss_descs_count;
3054
3055         int fs_len, hs_len, ss_len, ret, i;
3056         struct ffs_ep *eps_ptr;
3057
3058         /* Make it a single chunk, less management later on */
3059         vla_group(d);
3060         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3061         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3062                 full ? ffs->fs_descs_count + 1 : 0);
3063         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3064                 high ? ffs->hs_descs_count + 1 : 0);
3065         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3066                 super ? ffs->ss_descs_count + 1 : 0);
3067         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3068         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3069                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3070         vla_item_with_sz(d, char[16], ext_compat,
3071                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3072         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3073                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3074         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3075                          ffs->ms_os_descs_ext_prop_count);
3076         vla_item_with_sz(d, char, ext_prop_name,
3077                          ffs->ms_os_descs_ext_prop_name_len);
3078         vla_item_with_sz(d, char, ext_prop_data,
3079                          ffs->ms_os_descs_ext_prop_data_len);
3080         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3081         char *vlabuf;
3082
3083         /* Has descriptors only for speeds gadget does not support */
3084         if (!(full | high | super))
3085                 return -ENOTSUPP;
3086
3087         /* Allocate a single chunk, less management later on */
3088         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3089         if (!vlabuf)
3090                 return -ENOMEM;
3091
3092         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3093         ffs->ms_os_descs_ext_prop_name_avail =
3094                 vla_ptr(vlabuf, d, ext_prop_name);
3095         ffs->ms_os_descs_ext_prop_data_avail =
3096                 vla_ptr(vlabuf, d, ext_prop_data);
3097
3098         /* Copy descriptors  */
3099         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3100                ffs->raw_descs_length);
3101
3102         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3103         eps_ptr = vla_ptr(vlabuf, d, eps);
3104         for (i = 0; i < ffs->eps_count; i++)
3105                 eps_ptr[i].num = -1;
3106
3107         /* Save pointers
3108          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3109         */
3110         func->eps             = vla_ptr(vlabuf, d, eps);
3111         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3112
3113         /*
3114          * Go through all the endpoint descriptors and allocate
3115          * endpoints first, so that later we can rewrite the endpoint
3116          * numbers without worrying that it may be described later on.
3117          */
3118         if (full) {
3119                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3120                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3121                                       vla_ptr(vlabuf, d, raw_descs),
3122                                       d_raw_descs__sz,
3123                                       __ffs_func_bind_do_descs, func);
3124                 if (fs_len < 0) {
3125                         ret = fs_len;
3126                         goto error;
3127                 }
3128         } else {
3129                 fs_len = 0;
3130         }
3131
3132         if (high) {
3133                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3134                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3135                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3136                                       d_raw_descs__sz - fs_len,
3137                                       __ffs_func_bind_do_descs, func);
3138                 if (hs_len < 0) {
3139                         ret = hs_len;
3140                         goto error;
3141                 }
3142         } else {
3143                 hs_len = 0;
3144         }
3145
3146         if (super) {
3147                 func->function.ss_descriptors = func->function.ssp_descriptors =
3148                         vla_ptr(vlabuf, d, ss_descs);
3149                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3150                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3151                                 d_raw_descs__sz - fs_len - hs_len,
3152                                 __ffs_func_bind_do_descs, func);
3153                 if (ss_len < 0) {
3154                         ret = ss_len;
3155                         goto error;
3156                 }
3157         } else {
3158                 ss_len = 0;
3159         }
3160
3161         /*
3162          * Now handle interface numbers allocation and interface and
3163          * endpoint numbers rewriting.  We can do that in one go
3164          * now.
3165          */
3166         ret = ffs_do_descs(ffs->fs_descs_count +
3167                            (high ? ffs->hs_descs_count : 0) +
3168                            (super ? ffs->ss_descs_count : 0),
3169                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3170                            __ffs_func_bind_do_nums, func);
3171         if (ret < 0)
3172                 goto error;
3173
3174         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3175         if (c->cdev->use_os_string) {
3176                 for (i = 0; i < ffs->interfaces_count; ++i) {
3177                         struct usb_os_desc *desc;
3178
3179                         desc = func->function.os_desc_table[i].os_desc =
3180                                 vla_ptr(vlabuf, d, os_desc) +
3181                                 i * sizeof(struct usb_os_desc);
3182                         desc->ext_compat_id =
3183                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3184                         INIT_LIST_HEAD(&desc->ext_prop);
3185                 }
3186                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3187                                       vla_ptr(vlabuf, d, raw_descs) +
3188                                       fs_len + hs_len + ss_len,
3189                                       d_raw_descs__sz - fs_len - hs_len -
3190                                       ss_len,
3191                                       __ffs_func_bind_do_os_desc, func);
3192                 if (ret < 0)
3193                         goto error;
3194         }
3195         func->function.os_desc_n =
3196                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3197
3198         /* And we're done */
3199         ffs_event_add(ffs, FUNCTIONFS_BIND);
3200         return 0;
3201
3202 error:
3203         /* XXX Do we need to release all claimed endpoints here? */
3204         return ret;
3205 }
3206
3207 static int ffs_func_bind(struct usb_configuration *c,
3208                          struct usb_function *f)
3209 {
3210         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3211         struct ffs_function *func = ffs_func_from_usb(f);
3212         int ret;
3213
3214         if (IS_ERR(ffs_opts))
3215                 return PTR_ERR(ffs_opts);
3216
3217         ret = _ffs_func_bind(c, f);
3218         if (ret && !--ffs_opts->refcnt)
3219                 functionfs_unbind(func->ffs);
3220
3221         return ret;
3222 }
3223
3224
3225 /* Other USB function hooks *************************************************/
3226
3227 static void ffs_reset_work(struct work_struct *work)
3228 {
3229         struct ffs_data *ffs = container_of(work,
3230                 struct ffs_data, reset_work);
3231         ffs_data_reset(ffs);
3232 }
3233
3234 static int ffs_func_set_alt(struct usb_function *f,
3235                             unsigned interface, unsigned alt)
3236 {
3237         struct ffs_function *func = ffs_func_from_usb(f);
3238         struct ffs_data *ffs = func->ffs;
3239         int ret = 0, intf;
3240
3241         if (alt != (unsigned)-1) {
3242                 intf = ffs_func_revmap_intf(func, interface);
3243                 if (intf < 0)
3244                         return intf;
3245         }
3246
3247         if (ffs->func)
3248                 ffs_func_eps_disable(ffs->func);
3249
3250         if (ffs->state == FFS_DEACTIVATED) {
3251                 ffs->state = FFS_CLOSING;
3252                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3253                 schedule_work(&ffs->reset_work);
3254                 return -ENODEV;
3255         }
3256
3257         if (ffs->state != FFS_ACTIVE)
3258                 return -ENODEV;
3259
3260         if (alt == (unsigned)-1) {
3261                 ffs->func = NULL;
3262                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3263                 return 0;
3264         }
3265
3266         ffs->func = func;
3267         ret = ffs_func_eps_enable(func);
3268         if (ret >= 0)
3269                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3270         return ret;
3271 }
3272
3273 static void ffs_func_disable(struct usb_function *f)
3274 {
3275         ffs_func_set_alt(f, 0, (unsigned)-1);
3276 }
3277
3278 static int ffs_func_setup(struct usb_function *f,
3279                           const struct usb_ctrlrequest *creq)
3280 {
3281         struct ffs_function *func = ffs_func_from_usb(f);
3282         struct ffs_data *ffs = func->ffs;
3283         unsigned long flags;
3284         int ret;
3285
3286         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3287         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3288         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3289         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3290         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3291
3292         /*
3293          * Most requests directed to interface go through here
3294          * (notable exceptions are set/get interface) so we need to
3295          * handle them.  All other either handled by composite or
3296          * passed to usb_configuration->setup() (if one is set).  No
3297          * matter, we will handle requests directed to endpoint here
3298          * as well (as it's straightforward).  Other request recipient
3299          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3300          * is being used.
3301          */
3302         if (ffs->state != FFS_ACTIVE)
3303                 return -ENODEV;
3304
3305         switch (creq->bRequestType & USB_RECIP_MASK) {
3306         case USB_RECIP_INTERFACE:
3307                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3308                 if (ret < 0)
3309                         return ret;
3310                 break;
3311
3312         case USB_RECIP_ENDPOINT:
3313                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3314                 if (ret < 0)
3315                         return ret;
3316                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3317                         ret = func->ffs->eps_addrmap[ret];
3318                 break;
3319
3320         default:
3321                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3322                         ret = le16_to_cpu(creq->wIndex);
3323                 else
3324                         return -EOPNOTSUPP;
3325         }
3326
3327         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3328         ffs->ev.setup = *creq;
3329         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3330         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3331         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3332
3333         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3334 }
3335
3336 static bool ffs_func_req_match(struct usb_function *f,
3337                                const struct usb_ctrlrequest *creq,
3338                                bool config0)
3339 {
3340         struct ffs_function *func = ffs_func_from_usb(f);
3341
3342         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3343                 return false;
3344
3345         switch (creq->bRequestType & USB_RECIP_MASK) {
3346         case USB_RECIP_INTERFACE:
3347                 return (ffs_func_revmap_intf(func,
3348                                              le16_to_cpu(creq->wIndex)) >= 0);
3349         case USB_RECIP_ENDPOINT:
3350                 return (ffs_func_revmap_ep(func,
3351                                            le16_to_cpu(creq->wIndex)) >= 0);
3352         default:
3353                 return (bool) (func->ffs->user_flags &
3354                                FUNCTIONFS_ALL_CTRL_RECIP);
3355         }
3356 }
3357
3358 static void ffs_func_suspend(struct usb_function *f)
3359 {
3360         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3361 }
3362
3363 static void ffs_func_resume(struct usb_function *f)
3364 {
3365         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3366 }
3367
3368
3369 /* Endpoint and interface numbers reverse mapping ***************************/
3370
3371 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3372 {
3373         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3374         return num ? num : -EDOM;
3375 }
3376
3377 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3378 {
3379         short *nums = func->interfaces_nums;
3380         unsigned count = func->ffs->interfaces_count;
3381
3382         for (; count; --count, ++nums) {
3383                 if (*nums >= 0 && *nums == intf)
3384                         return nums - func->interfaces_nums;
3385         }
3386
3387         return -EDOM;
3388 }
3389
3390
3391 /* Devices management *******************************************************/
3392
3393 static LIST_HEAD(ffs_devices);
3394
3395 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3396 {
3397         struct ffs_dev *dev;
3398
3399         if (!name)
3400                 return NULL;
3401
3402         list_for_each_entry(dev, &ffs_devices, entry) {
3403                 if (strcmp(dev->name, name) == 0)
3404                         return dev;
3405         }
3406
3407         return NULL;
3408 }
3409
3410 /*
3411  * ffs_lock must be taken by the caller of this function
3412  */
3413 static struct ffs_dev *_ffs_get_single_dev(void)
3414 {
3415         struct ffs_dev *dev;
3416
3417         if (list_is_singular(&ffs_devices)) {
3418                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3419                 if (dev->single)
3420                         return dev;
3421         }
3422
3423         return NULL;
3424 }
3425
3426 /*
3427  * ffs_lock must be taken by the caller of this function
3428  */
3429 static struct ffs_dev *_ffs_find_dev(const char *name)
3430 {
3431         struct ffs_dev *dev;
3432
3433         dev = _ffs_get_single_dev();
3434         if (dev)
3435                 return dev;
3436
3437         return _ffs_do_find_dev(name);
3438 }
3439
3440 /* Configfs support *********************************************************/
3441
3442 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3443 {
3444         return container_of(to_config_group(item), struct f_fs_opts,
3445                             func_inst.group);
3446 }
3447
3448 static void ffs_attr_release(struct config_item *item)
3449 {
3450         struct f_fs_opts *opts = to_ffs_opts(item);
3451
3452         usb_put_function_instance(&opts->func_inst);
3453 }
3454
3455 static struct configfs_item_operations ffs_item_ops = {
3456         .release        = ffs_attr_release,
3457 };
3458
3459 static const struct config_item_type ffs_func_type = {
3460         .ct_item_ops    = &ffs_item_ops,
3461         .ct_owner       = THIS_MODULE,
3462 };
3463
3464
3465 /* Function registration interface ******************************************/
3466
3467 static void ffs_free_inst(struct usb_function_instance *f)
3468 {
3469         struct f_fs_opts *opts;
3470
3471         opts = to_f_fs_opts(f);
3472         ffs_release_dev(opts->dev);
3473         ffs_dev_lock();
3474         _ffs_free_dev(opts->dev);
3475         ffs_dev_unlock();
3476         kfree(opts);
3477 }
3478
3479 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3480 {
3481         if (strlen(name) >= sizeof_field(struct ffs_dev, name))
3482                 return -ENAMETOOLONG;
3483         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3484 }
3485
3486 static struct usb_function_instance *ffs_alloc_inst(void)
3487 {
3488         struct f_fs_opts *opts;
3489         struct ffs_dev *dev;
3490
3491         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3492         if (!opts)
3493                 return ERR_PTR(-ENOMEM);
3494
3495         opts->func_inst.set_inst_name = ffs_set_inst_name;
3496         opts->func_inst.free_func_inst = ffs_free_inst;
3497         ffs_dev_lock();
3498         dev = _ffs_alloc_dev();
3499         ffs_dev_unlock();
3500         if (IS_ERR(dev)) {
3501                 kfree(opts);
3502                 return ERR_CAST(dev);
3503         }
3504         opts->dev = dev;
3505         dev->opts = opts;
3506
3507         config_group_init_type_name(&opts->func_inst.group, "",
3508                                     &ffs_func_type);
3509         return &opts->func_inst;
3510 }
3511
3512 static void ffs_free(struct usb_function *f)
3513 {
3514         kfree(ffs_func_from_usb(f));
3515 }
3516
3517 static void ffs_func_unbind(struct usb_configuration *c,
3518                             struct usb_function *f)
3519 {
3520         struct ffs_function *func = ffs_func_from_usb(f);
3521         struct ffs_data *ffs = func->ffs;
3522         struct f_fs_opts *opts =
3523                 container_of(f->fi, struct f_fs_opts, func_inst);
3524         struct ffs_ep *ep = func->eps;
3525         unsigned count = ffs->eps_count;
3526         unsigned long flags;
3527
3528         if (ffs->func == func) {
3529                 ffs_func_eps_disable(func);
3530                 ffs->func = NULL;
3531         }
3532
3533         /* Drain any pending AIO completions */
3534         drain_workqueue(ffs->io_completion_wq);
3535
3536         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3537         if (!--opts->refcnt)
3538                 functionfs_unbind(ffs);
3539
3540         /* cleanup after autoconfig */
3541         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3542         while (count--) {
3543                 if (ep->ep && ep->req)
3544                         usb_ep_free_request(ep->ep, ep->req);
3545                 ep->req = NULL;
3546                 ++ep;
3547         }
3548         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3549         kfree(func->eps);
3550         func->eps = NULL;
3551         /*
3552          * eps, descriptors and interfaces_nums are allocated in the
3553          * same chunk so only one free is required.
3554          */
3555         func->function.fs_descriptors = NULL;
3556         func->function.hs_descriptors = NULL;
3557         func->function.ss_descriptors = NULL;
3558         func->function.ssp_descriptors = NULL;
3559         func->interfaces_nums = NULL;
3560
3561 }
3562
3563 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3564 {
3565         struct ffs_function *func;
3566
3567         func = kzalloc(sizeof(*func), GFP_KERNEL);
3568         if (!func)
3569                 return ERR_PTR(-ENOMEM);
3570
3571         func->function.name    = "Function FS Gadget";
3572
3573         func->function.bind    = ffs_func_bind;
3574         func->function.unbind  = ffs_func_unbind;
3575         func->function.set_alt = ffs_func_set_alt;
3576         func->function.disable = ffs_func_disable;
3577         func->function.setup   = ffs_func_setup;
3578         func->function.req_match = ffs_func_req_match;
3579         func->function.suspend = ffs_func_suspend;
3580         func->function.resume  = ffs_func_resume;
3581         func->function.free_func = ffs_free;
3582
3583         return &func->function;
3584 }
3585
3586 /*
3587  * ffs_lock must be taken by the caller of this function
3588  */
3589 static struct ffs_dev *_ffs_alloc_dev(void)
3590 {
3591         struct ffs_dev *dev;
3592         int ret;
3593
3594         if (_ffs_get_single_dev())
3595                         return ERR_PTR(-EBUSY);
3596
3597         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3598         if (!dev)
3599                 return ERR_PTR(-ENOMEM);
3600
3601         if (list_empty(&ffs_devices)) {
3602                 ret = functionfs_init();
3603                 if (ret) {
3604                         kfree(dev);
3605                         return ERR_PTR(ret);
3606                 }
3607         }
3608
3609         list_add(&dev->entry, &ffs_devices);
3610
3611         return dev;
3612 }
3613
3614 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3615 {
3616         struct ffs_dev *existing;
3617         int ret = 0;
3618
3619         ffs_dev_lock();
3620
3621         existing = _ffs_do_find_dev(name);
3622         if (!existing)
3623                 strscpy(dev->name, name, ARRAY_SIZE(dev->name));
3624         else if (existing != dev)
3625                 ret = -EBUSY;
3626
3627         ffs_dev_unlock();
3628
3629         return ret;
3630 }
3631 EXPORT_SYMBOL_GPL(ffs_name_dev);
3632
3633 int ffs_single_dev(struct ffs_dev *dev)
3634 {
3635         int ret;
3636
3637         ret = 0;
3638         ffs_dev_lock();
3639
3640         if (!list_is_singular(&ffs_devices))
3641                 ret = -EBUSY;
3642         else
3643                 dev->single = true;
3644
3645         ffs_dev_unlock();
3646         return ret;
3647 }
3648 EXPORT_SYMBOL_GPL(ffs_single_dev);
3649
3650 /*
3651  * ffs_lock must be taken by the caller of this function
3652  */
3653 static void _ffs_free_dev(struct ffs_dev *dev)
3654 {
3655         list_del(&dev->entry);
3656
3657         kfree(dev);
3658         if (list_empty(&ffs_devices))
3659                 functionfs_cleanup();
3660 }
3661
3662 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data)
3663 {
3664         int ret = 0;
3665         struct ffs_dev *ffs_dev;
3666
3667         ffs_dev_lock();
3668
3669         ffs_dev = _ffs_find_dev(dev_name);
3670         if (!ffs_dev) {
3671                 ret = -ENOENT;
3672         } else if (ffs_dev->mounted) {
3673                 ret = -EBUSY;
3674         } else if (ffs_dev->ffs_acquire_dev_callback &&
3675                    ffs_dev->ffs_acquire_dev_callback(ffs_dev)) {
3676                 ret = -ENOENT;
3677         } else {
3678                 ffs_dev->mounted = true;
3679                 ffs_dev->ffs_data = ffs_data;
3680                 ffs_data->private_data = ffs_dev;
3681         }
3682
3683         ffs_dev_unlock();
3684         return ret;
3685 }
3686
3687 static void ffs_release_dev(struct ffs_dev *ffs_dev)
3688 {
3689         ffs_dev_lock();
3690
3691         if (ffs_dev && ffs_dev->mounted) {
3692                 ffs_dev->mounted = false;
3693                 if (ffs_dev->ffs_data) {
3694                         ffs_dev->ffs_data->private_data = NULL;
3695                         ffs_dev->ffs_data = NULL;
3696                 }
3697
3698                 if (ffs_dev->ffs_release_dev_callback)
3699                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3700         }
3701
3702         ffs_dev_unlock();
3703 }
3704
3705 static int ffs_ready(struct ffs_data *ffs)
3706 {
3707         struct ffs_dev *ffs_obj;
3708         int ret = 0;
3709
3710         ffs_dev_lock();
3711
3712         ffs_obj = ffs->private_data;
3713         if (!ffs_obj) {
3714                 ret = -EINVAL;
3715                 goto done;
3716         }
3717         if (WARN_ON(ffs_obj->desc_ready)) {
3718                 ret = -EBUSY;
3719                 goto done;
3720         }
3721
3722         ffs_obj->desc_ready = true;
3723
3724         if (ffs_obj->ffs_ready_callback) {
3725                 ret = ffs_obj->ffs_ready_callback(ffs);
3726                 if (ret)
3727                         goto done;
3728         }
3729
3730         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3731 done:
3732         ffs_dev_unlock();
3733         return ret;
3734 }
3735
3736 static void ffs_closed(struct ffs_data *ffs)
3737 {
3738         struct ffs_dev *ffs_obj;
3739         struct f_fs_opts *opts;
3740         struct config_item *ci;
3741
3742         ffs_dev_lock();
3743
3744         ffs_obj = ffs->private_data;
3745         if (!ffs_obj)
3746                 goto done;
3747
3748         ffs_obj->desc_ready = false;
3749
3750         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3751             ffs_obj->ffs_closed_callback)
3752                 ffs_obj->ffs_closed_callback(ffs);
3753
3754         if (ffs_obj->opts)
3755                 opts = ffs_obj->opts;
3756         else
3757                 goto done;
3758
3759         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3760             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3761                 goto done;
3762
3763         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3764         ffs_dev_unlock();
3765
3766         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3767                 unregister_gadget_item(ci);
3768         return;
3769 done:
3770         ffs_dev_unlock();
3771 }
3772
3773 /* Misc helper functions ****************************************************/
3774
3775 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3776 {
3777         return nonblock
3778                 ? mutex_trylock(mutex) ? 0 : -EAGAIN
3779                 : mutex_lock_interruptible(mutex);
3780 }
3781
3782 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3783 {
3784         char *data;
3785
3786         if (!len)
3787                 return NULL;
3788
3789         data = memdup_user(buf, len);
3790         if (IS_ERR(data))
3791                 return data;
3792
3793         pr_vdebug("Buffer from user space:\n");
3794         ffs_dump_mem("", data, len);
3795
3796         return data;
3797 }
3798
3799 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3800 MODULE_LICENSE("GPL");
3801 MODULE_AUTHOR("Michal Nazarewicz");