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[];
 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         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 283
 284         spin_unlock_irq(&ffs->ev.waitq.lock);
 285
 286         req->buf      = data;
 287         req->length   = len;
 288
 289         /*
 290          * UDC layer requires to provide a buffer even for ZLP, but should
 291          * not use it at all. Let's provide some poisoned pointer to catch
 292          * possible bug in the driver.
 293          */
 294         if (req->buf == NULL)
 295                 req->buf = (void *)0xDEADBABE;
 296
 297         reinit_completion(&ffs->ep0req_completion);
 298
 299         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 300         if (ret < 0)
 301                 return ret;
 302
 303         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 304         if (ret) {
 305                 usb_ep_dequeue(ffs->gadget->ep0, req);
 306                 return -EINTR;
 307         }
 308
 309         ffs->setup_state = FFS_NO_SETUP;
 310         return req->status ? req->status : req->actual;
 311 }
 312
 313 static int __ffs_ep0_stall(struct ffs_data *ffs)
 314 {
 315         if (ffs->ev.can_stall) {
 316                 pr_vdebug("ep0 stall\n");
 317                 usb_ep_set_halt(ffs->gadget->ep0);
 318                 ffs->setup_state = FFS_NO_SETUP;
 319                 return -EL2HLT;
 320         } else {
 321                 pr_debug("bogus ep0 stall!\n");
 322                 return -ESRCH;
 323         }
 324 }
 325
 326 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 327                              size_t len, loff_t *ptr)
 328 {
 329         struct ffs_data *ffs = file->private_data;
 330         ssize_t ret;
 331         char *data;
 332
 333         ENTER();
 334
 335         /* Fast check if setup was canceled */
 336         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 337                 return -EIDRM;
 338
 339         /* Acquire mutex */
 340         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 341         if (ret < 0)
 342                 return ret;
 343
 344         /* Check state */
 345         switch (ffs->state) {
 346         case FFS_READ_DESCRIPTORS:
 347         case FFS_READ_STRINGS:
 348                 /* Copy data */
 349                 if (len < 16) {
 350                         ret = -EINVAL;
 351                         break;
 352                 }
 353
 354                 data = ffs_prepare_buffer(buf, len);
 355                 if (IS_ERR(data)) {
 356                         ret = PTR_ERR(data);
 357                         break;
 358                 }
 359
 360                 /* Handle data */
 361                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 362                         pr_info("read descriptors\n");
 363                         ret = __ffs_data_got_descs(ffs, data, len);
 364                         if (ret < 0)
 365                                 break;
 366
 367                         ffs->state = FFS_READ_STRINGS;
 368                         ret = len;
 369                 } else {
 370                         pr_info("read strings\n");
 371                         ret = __ffs_data_got_strings(ffs, data, len);
 372                         if (ret < 0)
 373                                 break;
 374
 375                         ret = ffs_epfiles_create(ffs);
 376                         if (ret) {
 377                                 ffs->state = FFS_CLOSING;
 378                                 break;
 379                         }
 380
 381                         ffs->state = FFS_ACTIVE;
 382                         mutex_unlock(&ffs->mutex);
 383
 384                         ret = ffs_ready(ffs);
 385                         if (ret < 0) {
 386                                 ffs->state = FFS_CLOSING;
 387                                 return ret;
 388                         }
 389
 390                         return len;
 391                 }
 392                 break;
 393
 394         case FFS_ACTIVE:
 395                 data = NULL;
 396                 /*
 397                  * We're called from user space, we can use _irq
 398                  * rather then _irqsave
 399                  */
 400                 spin_lock_irq(&ffs->ev.waitq.lock);
 401                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 402                 case FFS_SETUP_CANCELLED:
 403                         ret = -EIDRM;
 404                         goto done_spin;
 405
 406                 case FFS_NO_SETUP:
 407                         ret = -ESRCH;
 408                         goto done_spin;
 409
 410                 case FFS_SETUP_PENDING:
 411                         break;
 412                 }
 413
 414                 /* FFS_SETUP_PENDING */
 415                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 416                         spin_unlock_irq(&ffs->ev.waitq.lock);
 417                         ret = __ffs_ep0_stall(ffs);
 418                         break;
 419                 }
 420
 421                 /* FFS_SETUP_PENDING and not stall */
 422                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 423
 424                 spin_unlock_irq(&ffs->ev.waitq.lock);
 425
 426                 data = ffs_prepare_buffer(buf, len);
 427                 if (IS_ERR(data)) {
 428                         ret = PTR_ERR(data);
 429                         break;
 430                 }
 431
 432                 spin_lock_irq(&ffs->ev.waitq.lock);
 433
 434                 /*
 435                  * We are guaranteed to be still in FFS_ACTIVE state
 436                  * but the state of setup could have changed from
 437                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 438                  * to check for that.  If that happened we copied data
 439                  * from user space in vain but it's unlikely.
 440                  *
 441                  * For sure we are not in FFS_NO_SETUP since this is
 442                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 443                  * transition can be performed and it's protected by
 444                  * mutex.
 445                  */
 446                 if (ffs_setup_state_clear_cancelled(ffs) ==
 447                     FFS_SETUP_CANCELLED) {
 448                         ret = -EIDRM;
 449 done_spin:
 450                         spin_unlock_irq(&ffs->ev.waitq.lock);
 451                 } else {
 452                         /* unlocks spinlock */
 453                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 454                 }
 455                 kfree(data);
 456                 break;
 457
 458         default:
 459                 ret = -EBADFD;
 460                 break;
 461         }
 462
 463         mutex_unlock(&ffs->mutex);
 464         return ret;
 465 }
 466
 467 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 468 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 469                                      size_t n)
 470         __releases(&ffs->ev.waitq.lock)
 471 {
 472         /*
 473          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 474          * size of ffs->ev.types array (which is four) so that's how much space
 475          * we reserve.
 476          */
 477         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 478         const size_t size = n * sizeof *events;
 479         unsigned i = 0;
 480
 481         memset(events, 0, size);
 482
 483         do {
 484                 events[i].type = ffs->ev.types[i];
 485                 if (events[i].type == FUNCTIONFS_SETUP) {
 486                         events[i].u.setup = ffs->ev.setup;
 487                         ffs->setup_state = FFS_SETUP_PENDING;
 488                 }
 489         } while (++i < n);
 490
 491         ffs->ev.count -= n;
 492         if (ffs->ev.count)
 493                 memmove(ffs->ev.types, ffs->ev.types + n,
 494                         ffs->ev.count * sizeof *ffs->ev.types);
 495
 496         spin_unlock_irq(&ffs->ev.waitq.lock);
 497         mutex_unlock(&ffs->mutex);
 498
 499         return copy_to_user(buf, events, size) ? -EFAULT : size;
 500 }
 501
 502 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 503                             size_t len, loff_t *ptr)
 504 {
 505         struct ffs_data *ffs = file->private_data;
 506         char *data = NULL;
 507         size_t n;
 508         int ret;
 509
 510         ENTER();
 511
 512         /* Fast check if setup was canceled */
 513         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 514                 return -EIDRM;
 515
 516         /* Acquire mutex */
 517         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 518         if (ret < 0)
 519                 return ret;
 520
 521         /* Check state */
 522         if (ffs->state != FFS_ACTIVE) {
 523                 ret = -EBADFD;
 524                 goto done_mutex;
 525         }
 526
 527         /*
 528          * We're called from user space, we can use _irq rather then
 529          * _irqsave
 530          */
 531         spin_lock_irq(&ffs->ev.waitq.lock);
 532
 533         switch (ffs_setup_state_clear_cancelled(ffs)) {
 534         case FFS_SETUP_CANCELLED:
 535                 ret = -EIDRM;
 536                 break;
 537
 538         case FFS_NO_SETUP:
 539                 n = len / sizeof(struct usb_functionfs_event);
 540                 if (!n) {
 541                         ret = -EINVAL;
 542                         break;
 543                 }
 544
 545                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 546                         ret = -EAGAIN;
 547                         break;
 548                 }
 549
 550                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 551                                                         ffs->ev.count)) {
 552                         ret = -EINTR;
 553                         break;
 554                 }
 555
 556                 /* unlocks spinlock */
 557                 return __ffs_ep0_read_events(ffs, buf,
 558                                              min(n, (size_t)ffs->ev.count));
 559
 560         case FFS_SETUP_PENDING:
 561                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 562                         spin_unlock_irq(&ffs->ev.waitq.lock);
 563                         ret = __ffs_ep0_stall(ffs);
 564                         goto done_mutex;
 565                 }
 566
 567                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 568
 569                 spin_unlock_irq(&ffs->ev.waitq.lock);
 570
 571                 if (len) {
 572                         data = kmalloc(len, GFP_KERNEL);
 573                         if (!data) {
 574                                 ret = -ENOMEM;
 575                                 goto done_mutex;
 576                         }
 577                 }
 578
 579                 spin_lock_irq(&ffs->ev.waitq.lock);
 580
 581                 /* See ffs_ep0_write() */
 582                 if (ffs_setup_state_clear_cancelled(ffs) ==
 583                     FFS_SETUP_CANCELLED) {
 584                         ret = -EIDRM;
 585                         break;
 586                 }
 587
 588                 /* unlocks spinlock */
 589                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 590                 if ((ret > 0) && (copy_to_user(buf, data, len)))
 591                         ret = -EFAULT;
 592                 goto done_mutex;
 593
 594         default:
 595                 ret = -EBADFD;
 596                 break;
 597         }
 598
 599         spin_unlock_irq(&ffs->ev.waitq.lock);
 600 done_mutex:
 601         mutex_unlock(&ffs->mutex);
 602         kfree(data);
 603         return ret;
 604 }
 605
 606 static int ffs_ep0_open(struct inode *inode, struct file *file)
 607 {
 608         struct ffs_data *ffs = inode->i_private;
 609
 610         ENTER();
 611
 612         if (ffs->state == FFS_CLOSING)
 613                 return -EBUSY;
 614
 615         file->private_data = ffs;
 616         ffs_data_opened(ffs);
 617
 618         return stream_open(inode, file);
 619 }
 620
 621 static int ffs_ep0_release(struct inode *inode, struct file *file)
 622 {
 623         struct ffs_data *ffs = file->private_data;
 624
 625         ENTER();
 626
 627         ffs_data_closed(ffs);
 628
 629         return 0;
 630 }
 631
 632 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 633 {
 634         struct ffs_data *ffs = file->private_data;
 635         struct usb_gadget *gadget = ffs->gadget;
 636         long ret;
 637
 638         ENTER();
 639
 640         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 641                 struct ffs_function *func = ffs->func;
 642                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 643         } else if (gadget && gadget->ops->ioctl) {
 644                 ret = gadget->ops->ioctl(gadget, code, value);
 645         } else {
 646                 ret = -ENOTTY;
 647         }
 648
 649         return ret;
 650 }
 651
 652 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 653 {
 654         struct ffs_data *ffs = file->private_data;
 655         __poll_t mask = EPOLLWRNORM;
 656         int ret;
 657
 658         poll_wait(file, &ffs->ev.waitq, wait);
 659
 660         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 661         if (ret < 0)
 662                 return mask;
 663
 664         switch (ffs->state) {
 665         case FFS_READ_DESCRIPTORS:
 666         case FFS_READ_STRINGS:
 667                 mask |= EPOLLOUT;
 668                 break;
 669
 670         case FFS_ACTIVE:
 671                 switch (ffs->setup_state) {
 672                 case FFS_NO_SETUP:
 673                         if (ffs->ev.count)
 674                                 mask |= EPOLLIN;
 675                         break;
 676
 677                 case FFS_SETUP_PENDING:
 678                 case FFS_SETUP_CANCELLED:
 679                         mask |= (EPOLLIN | EPOLLOUT);
 680                         break;
 681                 }
 682                 break;
 683
 684         case FFS_CLOSING:
 685                 break;
 686         case FFS_DEACTIVATED:
 687                 break;
 688         }
 689
 690         mutex_unlock(&ffs->mutex);
 691
 692         return mask;
 693 }
 694
 695 static const struct file_operations ffs_ep0_operations = {
 696         .llseek =       no_llseek,
 697
 698         .open =         ffs_ep0_open,
 699         .write =        ffs_ep0_write,
 700         .read =         ffs_ep0_read,
 701         .release =      ffs_ep0_release,
 702         .unlocked_ioctl =       ffs_ep0_ioctl,
 703         .poll =         ffs_ep0_poll,
 704 };
 705
 706
 707 /* "Normal" endpoints operations ********************************************/
 708
 709 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 710 {
 711         struct ffs_io_data *io_data = req->context;
 712
 713         ENTER();
 714         if (req->status)
 715                 io_data->status = req->status;
 716         else
 717                 io_data->status = req->actual;
 718
 719         complete(&io_data->done);
 720 }
 721
 722 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 723 {
 724         ssize_t ret = copy_to_iter(data, data_len, iter);
 725         if (ret == data_len)
 726                 return ret;
 727
 728         if (iov_iter_count(iter))
 729                 return -EFAULT;
 730
 731         /*
 732          * Dear user space developer!
 733          *
 734          * TL;DR: To stop getting below error message in your kernel log, change
 735          * user space code using functionfs to align read buffers to a max
 736          * packet size.
 737          *
 738          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 739          * packet size.  When unaligned buffer is passed to functionfs, it
 740          * internally uses a larger, aligned buffer so that such UDCs are happy.
 741          *
 742          * Unfortunately, this means that host may send more data than was
 743          * requested in read(2) system call.  f_fs doesn’t know what to do with
 744          * that excess data so it simply drops it.
 745          *
 746          * Was the buffer aligned in the first place, no such problem would
 747          * happen.
 748          *
 749          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 750          * by splitting a request into multiple parts.  This splitting may still
 751          * be a problem though so it’s likely best to align the buffer
 752          * regardless of it being AIO or not..
 753          *
 754          * This only affects OUT endpoints, i.e. reading data with a read(2),
 755          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 756          * affected.
 757          */
 758         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 759                "Align read buffer size to max packet size to avoid the problem.\n",
 760                data_len, ret);
 761
 762         return ret;
 763 }
 764
 765 /*
 766  * allocate a virtually contiguous buffer and create a scatterlist describing it
 767  * @sg_table    - pointer to a place to be filled with sg_table contents
 768  * @size        - required buffer size
 769  */
 770 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 771 {
 772         struct page **pages;
 773         void *vaddr, *ptr;
 774         unsigned int n_pages;
 775         int i;
 776
 777         vaddr = vmalloc(sz);
 778         if (!vaddr)
 779                 return NULL;
 780
 781         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 782         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 783         if (!pages) {
 784                 vfree(vaddr);
 785
 786                 return NULL;
 787         }
 788         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 789                 pages[i] = vmalloc_to_page(ptr);
 790
 791         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 792                 kvfree(pages);
 793                 vfree(vaddr);
 794
 795                 return NULL;
 796         }
 797         kvfree(pages);
 798
 799         return vaddr;
 800 }
 801
 802 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 803         size_t data_len)
 804 {
 805         if (io_data->use_sg)
 806                 return ffs_build_sg_list(&io_data->sgt, data_len);
 807
 808         return kmalloc(data_len, GFP_KERNEL);
 809 }
 810
 811 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 812 {
 813         if (!io_data->buf)
 814                 return;
 815
 816         if (io_data->use_sg) {
 817                 sg_free_table(&io_data->sgt);
 818                 vfree(io_data->buf);
 819         } else {
 820                 kfree(io_data->buf);
 821         }
 822 }
 823
 824 static void ffs_user_copy_worker(struct work_struct *work)
 825 {
 826         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 827                                                    work);
 828         int ret = io_data->req->status ? io_data->req->status :
 829                                          io_data->req->actual;
 830         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 831
 832         if (io_data->read && ret > 0) {
 833                 kthread_use_mm(io_data->mm);
 834                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 835                 kthread_unuse_mm(io_data->mm);
 836         }
 837
 838         io_data->kiocb->ki_complete(io_data->kiocb, ret);
 839
 840         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 841                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 842
 843         usb_ep_free_request(io_data->ep, io_data->req);
 844
 845         if (io_data->read)
 846                 kfree(io_data->to_free);
 847         ffs_free_buffer(io_data);
 848         kfree(io_data);
 849 }
 850
 851 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 852                                          struct usb_request *req)
 853 {
 854         struct ffs_io_data *io_data = req->context;
 855         struct ffs_data *ffs = io_data->ffs;
 856
 857         ENTER();
 858
 859         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 860         queue_work(ffs->io_completion_wq, &io_data->work);
 861 }
 862
 863 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 864 {
 865         /*
 866          * See comment in struct ffs_epfile for full read_buffer pointer
 867          * synchronisation story.
 868          */
 869         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 870         if (buf && buf != READ_BUFFER_DROP)
 871                 kfree(buf);
 872 }
 873
 874 /* Assumes epfile->mutex is held. */
 875 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 876                                           struct iov_iter *iter)
 877 {
 878         /*
 879          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 880          * the buffer while we are using it.  See comment in struct ffs_epfile
 881          * for full read_buffer pointer synchronisation story.
 882          */
 883         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 884         ssize_t ret;
 885         if (!buf || buf == READ_BUFFER_DROP)
 886                 return 0;
 887
 888         ret = copy_to_iter(buf->data, buf->length, iter);
 889         if (buf->length == ret) {
 890                 kfree(buf);
 891                 return ret;
 892         }
 893
 894         if (iov_iter_count(iter)) {
 895                 ret = -EFAULT;
 896         } else {
 897                 buf->length -= ret;
 898                 buf->data += ret;
 899         }
 900
 901         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 902                 kfree(buf);
 903
 904         return ret;
 905 }
 906
 907 /* Assumes epfile->mutex is held. */
 908 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 909                                       void *data, int data_len,
 910                                       struct iov_iter *iter)
 911 {
 912         struct ffs_buffer *buf;
 913
 914         ssize_t ret = copy_to_iter(data, data_len, iter);
 915         if (data_len == ret)
 916                 return ret;
 917
 918         if (iov_iter_count(iter))
 919                 return -EFAULT;
 920
 921         /* See ffs_copy_to_iter for more context. */
 922         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 923                 data_len, ret);
 924
 925         data_len -= ret;
 926         buf = kmalloc(struct_size(buf, storage, data_len), GFP_KERNEL);
 927         if (!buf)
 928                 return -ENOMEM;
 929         buf->length = data_len;
 930         buf->data = buf->storage;
 931         memcpy(buf->storage, data + ret, flex_array_size(buf, storage, data_len));
 932
 933         /*
 934          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 935          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 936          * in struct ffs_epfile for full read_buffer pointer synchronisation
 937          * story.
 938          */
 939         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 940                 kfree(buf);
 941
 942         return ret;
 943 }
 944
 945 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 946 {
 947         struct ffs_epfile *epfile = file->private_data;
 948         struct usb_request *req;
 949         struct ffs_ep *ep;
 950         char *data = NULL;
 951         ssize_t ret, data_len = -EINVAL;
 952         int halt;
 953
 954         /* Are we still active? */
 955         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 956                 return -ENODEV;
 957
 958         /* Wait for endpoint to be enabled */
 959         ep = epfile->ep;
 960         if (!ep) {
 961                 if (file->f_flags & O_NONBLOCK)
 962                         return -EAGAIN;
 963
 964                 ret = wait_event_interruptible(
 965                                 epfile->ffs->wait, (ep = epfile->ep));
 966                 if (ret)
 967                         return -EINTR;
 968         }
 969
 970         /* Do we halt? */
 971         halt = (!io_data->read == !epfile->in);
 972         if (halt && epfile->isoc)
 973                 return -EINVAL;
 974
 975         /* We will be using request and read_buffer */
 976         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 977         if (ret)
 978                 goto error;
 979
 980         /* Allocate & copy */
 981         if (!halt) {
 982                 struct usb_gadget *gadget;
 983
 984                 /*
 985                  * Do we have buffered data from previous partial read?  Check
 986                  * that for synchronous case only because we do not have
 987                  * facility to ‘wake up’ a pending asynchronous read and push
 988                  * buffered data to it which we would need to make things behave
 989                  * consistently.
 990                  */
 991                 if (!io_data->aio && io_data->read) {
 992                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 993                         if (ret)
 994                                 goto error_mutex;
 995                 }
 996
 997                 /*
 998                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 999                  * before the waiting completes, so do not assign to 'gadget'
1000                  * earlier
1001                  */
1002                 gadget = epfile->ffs->gadget;
1003
1004                 spin_lock_irq(&epfile->ffs->eps_lock);
1005                 /* In the meantime, endpoint got disabled or changed. */
1006                 if (epfile->ep != ep) {
1007                         ret = -ESHUTDOWN;
1008                         goto error_lock;
1009                 }
1010                 data_len = iov_iter_count(&io_data->data);
1011                 /*
1012                  * Controller may require buffer size to be aligned to
1013                  * maxpacketsize of an out endpoint.
1014                  */
1015                 if (io_data->read)
1016                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1017
1018                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1019                 spin_unlock_irq(&epfile->ffs->eps_lock);
1020
1021                 data = ffs_alloc_buffer(io_data, data_len);
1022                 if (!data) {
1023                         ret = -ENOMEM;
1024                         goto error_mutex;
1025                 }
1026                 if (!io_data->read &&
1027                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1028                         ret = -EFAULT;
1029                         goto error_mutex;
1030                 }
1031         }
1032
1033         spin_lock_irq(&epfile->ffs->eps_lock);
1034
1035         if (epfile->ep != ep) {
1036                 /* In the meantime, endpoint got disabled or changed. */
1037                 ret = -ESHUTDOWN;
1038         } else if (halt) {
1039                 ret = usb_ep_set_halt(ep->ep);
1040                 if (!ret)
1041                         ret = -EBADMSG;
1042         } else if (data_len == -EINVAL) {
1043                 /*
1044                  * Sanity Check: even though data_len can't be used
1045                  * uninitialized at the time I write this comment, some
1046                  * compilers complain about this situation.
1047                  * In order to keep the code clean from warnings, data_len is
1048                  * being initialized to -EINVAL during its declaration, which
1049                  * means we can't rely on compiler anymore to warn no future
1050                  * changes won't result in data_len being used uninitialized.
1051                  * For such reason, we're adding this redundant sanity check
1052                  * here.
1053                  */
1054                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1055                 ret = -EINVAL;
1056         } else if (!io_data->aio) {
1057                 bool interrupted = false;
1058
1059                 req = ep->req;
1060                 if (io_data->use_sg) {
1061                         req->buf = NULL;
1062                         req->sg = io_data->sgt.sgl;
1063                         req->num_sgs = io_data->sgt.nents;
1064                 } else {
1065                         req->buf = data;
1066                         req->num_sgs = 0;
1067                 }
1068                 req->length = data_len;
1069
1070                 io_data->buf = data;
1071
1072                 init_completion(&io_data->done);
1073                 req->context  = io_data;
1074                 req->complete = ffs_epfile_io_complete;
1075
1076                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1077                 if (ret < 0)
1078                         goto error_lock;
1079
1080                 spin_unlock_irq(&epfile->ffs->eps_lock);
1081
1082                 if (wait_for_completion_interruptible(&io_data->done)) {
1083                         spin_lock_irq(&epfile->ffs->eps_lock);
1084                         if (epfile->ep != ep) {
1085                                 ret = -ESHUTDOWN;
1086                                 goto error_lock;
1087                         }
1088                         /*
1089                          * To avoid race condition with ffs_epfile_io_complete,
1090                          * dequeue the request first then check
1091                          * status. usb_ep_dequeue API should guarantee no race
1092                          * condition with req->complete callback.
1093                          */
1094                         usb_ep_dequeue(ep->ep, req);
1095                         spin_unlock_irq(&epfile->ffs->eps_lock);
1096                         wait_for_completion(&io_data->done);
1097                         interrupted = io_data->status < 0;
1098                 }
1099
1100                 if (interrupted)
1101                         ret = -EINTR;
1102                 else if (io_data->read && io_data->status > 0)
1103                         ret = __ffs_epfile_read_data(epfile, data, io_data->status,
1104                                                      &io_data->data);
1105                 else
1106                         ret = io_data->status;
1107                 goto error_mutex;
1108         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1109                 ret = -ENOMEM;
1110         } else {
1111                 if (io_data->use_sg) {
1112                         req->buf = NULL;
1113                         req->sg = io_data->sgt.sgl;
1114                         req->num_sgs = io_data->sgt.nents;
1115                 } else {
1116                         req->buf = data;
1117                         req->num_sgs = 0;
1118                 }
1119                 req->length = data_len;
1120
1121                 io_data->buf = data;
1122                 io_data->ep = ep->ep;
1123                 io_data->req = req;
1124                 io_data->ffs = epfile->ffs;
1125
1126                 req->context  = io_data;
1127                 req->complete = ffs_epfile_async_io_complete;
1128
1129                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1130                 if (ret) {
1131                         io_data->req = NULL;
1132                         usb_ep_free_request(ep->ep, req);
1133                         goto error_lock;
1134                 }
1135
1136                 ret = -EIOCBQUEUED;
1137                 /*
1138                  * Do not kfree the buffer in this function.  It will be freed
1139                  * by ffs_user_copy_worker.
1140                  */
1141                 data = NULL;
1142         }
1143
1144 error_lock:
1145         spin_unlock_irq(&epfile->ffs->eps_lock);
1146 error_mutex:
1147         mutex_unlock(&epfile->mutex);
1148 error:
1149         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1150                 ffs_free_buffer(io_data);
1151         return ret;
1152 }
1153
1154 static int
1155 ffs_epfile_open(struct inode *inode, struct file *file)
1156 {
1157         struct ffs_epfile *epfile = inode->i_private;
1158
1159         ENTER();
1160
1161         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1162                 return -ENODEV;
1163
1164         file->private_data = epfile;
1165         ffs_data_opened(epfile->ffs);
1166
1167         return stream_open(inode, file);
1168 }
1169
1170 static int ffs_aio_cancel(struct kiocb *kiocb)
1171 {
1172         struct ffs_io_data *io_data = kiocb->private;
1173         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1174         unsigned long flags;
1175         int value;
1176
1177         ENTER();
1178
1179         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1180
1181         if (io_data && io_data->ep && io_data->req)
1182                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1183         else
1184                 value = -EINVAL;
1185
1186         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1187
1188         return value;
1189 }
1190
1191 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1192 {
1193         struct ffs_io_data io_data, *p = &io_data;
1194         ssize_t res;
1195
1196         ENTER();
1197
1198         if (!is_sync_kiocb(kiocb)) {
1199                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1200                 if (!p)
1201                         return -ENOMEM;
1202                 p->aio = true;
1203         } else {
1204                 memset(p, 0, sizeof(*p));
1205                 p->aio = false;
1206         }
1207
1208         p->read = false;
1209         p->kiocb = kiocb;
1210         p->data = *from;
1211         p->mm = current->mm;
1212
1213         kiocb->private = p;
1214
1215         if (p->aio)
1216                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1217
1218         res = ffs_epfile_io(kiocb->ki_filp, p);
1219         if (res == -EIOCBQUEUED)
1220                 return res;
1221         if (p->aio)
1222                 kfree(p);
1223         else
1224                 *from = p->data;
1225         return res;
1226 }
1227
1228 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1229 {
1230         struct ffs_io_data io_data, *p = &io_data;
1231         ssize_t res;
1232
1233         ENTER();
1234
1235         if (!is_sync_kiocb(kiocb)) {
1236                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1237                 if (!p)
1238                         return -ENOMEM;
1239                 p->aio = true;
1240         } else {
1241                 memset(p, 0, sizeof(*p));
1242                 p->aio = false;
1243         }
1244
1245         p->read = true;
1246         p->kiocb = kiocb;
1247         if (p->aio) {
1248                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1249                 if (!p->to_free) {
1250                         kfree(p);
1251                         return -ENOMEM;
1252                 }
1253         } else {
1254                 p->data = *to;
1255                 p->to_free = NULL;
1256         }
1257         p->mm = current->mm;
1258
1259         kiocb->private = p;
1260
1261         if (p->aio)
1262                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1263
1264         res = ffs_epfile_io(kiocb->ki_filp, p);
1265         if (res == -EIOCBQUEUED)
1266                 return res;
1267
1268         if (p->aio) {
1269                 kfree(p->to_free);
1270                 kfree(p);
1271         } else {
1272                 *to = p->data;
1273         }
1274         return res;
1275 }
1276
1277 static int
1278 ffs_epfile_release(struct inode *inode, struct file *file)
1279 {
1280         struct ffs_epfile *epfile = inode->i_private;
1281
1282         ENTER();
1283
1284         __ffs_epfile_read_buffer_free(epfile);
1285         ffs_data_closed(epfile->ffs);
1286
1287         return 0;
1288 }
1289
1290 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1291                              unsigned long value)
1292 {
1293         struct ffs_epfile *epfile = file->private_data;
1294         struct ffs_ep *ep;
1295         int ret;
1296
1297         ENTER();
1298
1299         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1300                 return -ENODEV;
1301
1302         /* Wait for endpoint to be enabled */
1303         ep = epfile->ep;
1304         if (!ep) {
1305                 if (file->f_flags & O_NONBLOCK)
1306                         return -EAGAIN;
1307
1308                 ret = wait_event_interruptible(
1309                                 epfile->ffs->wait, (ep = epfile->ep));
1310                 if (ret)
1311                         return -EINTR;
1312         }
1313
1314         spin_lock_irq(&epfile->ffs->eps_lock);
1315
1316         /* In the meantime, endpoint got disabled or changed. */
1317         if (epfile->ep != ep) {
1318                 spin_unlock_irq(&epfile->ffs->eps_lock);
1319                 return -ESHUTDOWN;
1320         }
1321
1322         switch (code) {
1323         case FUNCTIONFS_FIFO_STATUS:
1324                 ret = usb_ep_fifo_status(epfile->ep->ep);
1325                 break;
1326         case FUNCTIONFS_FIFO_FLUSH:
1327                 usb_ep_fifo_flush(epfile->ep->ep);
1328                 ret = 0;
1329                 break;
1330         case FUNCTIONFS_CLEAR_HALT:
1331                 ret = usb_ep_clear_halt(epfile->ep->ep);
1332                 break;
1333         case FUNCTIONFS_ENDPOINT_REVMAP:
1334                 ret = epfile->ep->num;
1335                 break;
1336         case FUNCTIONFS_ENDPOINT_DESC:
1337         {
1338                 int desc_idx;
1339                 struct usb_endpoint_descriptor desc1, *desc;
1340
1341                 switch (epfile->ffs->gadget->speed) {
1342                 case USB_SPEED_SUPER:
1343                 case USB_SPEED_SUPER_PLUS:
1344                         desc_idx = 2;
1345                         break;
1346                 case USB_SPEED_HIGH:
1347                         desc_idx = 1;
1348                         break;
1349                 default:
1350                         desc_idx = 0;
1351                 }
1352
1353                 desc = epfile->ep->descs[desc_idx];
1354                 memcpy(&desc1, desc, desc->bLength);
1355
1356                 spin_unlock_irq(&epfile->ffs->eps_lock);
1357                 ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
1358                 if (ret)
1359                         ret = -EFAULT;
1360                 return ret;
1361         }
1362         default:
1363                 ret = -ENOTTY;
1364         }
1365         spin_unlock_irq(&epfile->ffs->eps_lock);
1366
1367         return ret;
1368 }
1369
1370 static const struct file_operations ffs_epfile_operations = {
1371         .llseek =       no_llseek,
1372
1373         .open =         ffs_epfile_open,
1374         .write_iter =   ffs_epfile_write_iter,
1375         .read_iter =    ffs_epfile_read_iter,
1376         .release =      ffs_epfile_release,
1377         .unlocked_ioctl =       ffs_epfile_ioctl,
1378         .compat_ioctl = compat_ptr_ioctl,
1379 };
1380
1381
1382 /* File system and super block operations ***********************************/
1383
1384 /*
1385  * Mounting the file system creates a controller file, used first for
1386  * function configuration then later for event monitoring.
1387  */
1388
1389 static struct inode *__must_check
1390 ffs_sb_make_inode(struct super_block *sb, void *data,
1391                   const struct file_operations *fops,
1392                   const struct inode_operations *iops,
1393                   struct ffs_file_perms *perms)
1394 {
1395         struct inode *inode;
1396
1397         ENTER();
1398
1399         inode = new_inode(sb);
1400
1401         if (inode) {
1402                 struct timespec64 ts = current_time(inode);
1403
1404                 inode->i_ino     = get_next_ino();
1405                 inode->i_mode    = perms->mode;
1406                 inode->i_uid     = perms->uid;
1407                 inode->i_gid     = perms->gid;
1408                 inode->i_atime   = ts;
1409                 inode->i_mtime   = ts;
1410                 inode->i_ctime   = ts;
1411                 inode->i_private = data;
1412                 if (fops)
1413                         inode->i_fop = fops;
1414                 if (iops)
1415                         inode->i_op  = iops;
1416         }
1417
1418         return inode;
1419 }
1420
1421 /* Create "regular" file */
1422 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1423                                         const char *name, void *data,
1424                                         const struct file_operations *fops)
1425 {
1426         struct ffs_data *ffs = sb->s_fs_info;
1427         struct dentry   *dentry;
1428         struct inode    *inode;
1429
1430         ENTER();
1431
1432         dentry = d_alloc_name(sb->s_root, name);
1433         if (!dentry)
1434                 return NULL;
1435
1436         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1437         if (!inode) {
1438                 dput(dentry);
1439                 return NULL;
1440         }
1441
1442         d_add(dentry, inode);
1443         return dentry;
1444 }
1445
1446 /* Super block */
1447 static const struct super_operations ffs_sb_operations = {
1448         .statfs =       simple_statfs,
1449         .drop_inode =   generic_delete_inode,
1450 };
1451
1452 struct ffs_sb_fill_data {
1453         struct ffs_file_perms perms;
1454         umode_t root_mode;
1455         const char *dev_name;
1456         bool no_disconnect;
1457         struct ffs_data *ffs_data;
1458 };
1459
1460 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1461 {
1462         struct ffs_sb_fill_data *data = fc->fs_private;
1463         struct inode    *inode;
1464         struct ffs_data *ffs = data->ffs_data;
1465
1466         ENTER();
1467
1468         ffs->sb              = sb;
1469         data->ffs_data       = NULL;
1470         sb->s_fs_info        = ffs;
1471         sb->s_blocksize      = PAGE_SIZE;
1472         sb->s_blocksize_bits = PAGE_SHIFT;
1473         sb->s_magic          = FUNCTIONFS_MAGIC;
1474         sb->s_op             = &ffs_sb_operations;
1475         sb->s_time_gran      = 1;
1476
1477         /* Root inode */
1478         data->perms.mode = data->root_mode;
1479         inode = ffs_sb_make_inode(sb, NULL,
1480                                   &simple_dir_operations,
1481                                   &simple_dir_inode_operations,
1482                                   &data->perms);
1483         sb->s_root = d_make_root(inode);
1484         if (!sb->s_root)
1485                 return -ENOMEM;
1486
1487         /* EP0 file */
1488         if (!ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations))
1489                 return -ENOMEM;
1490
1491         return 0;
1492 }
1493
1494 enum {
1495         Opt_no_disconnect,
1496         Opt_rmode,
1497         Opt_fmode,
1498         Opt_mode,
1499         Opt_uid,
1500         Opt_gid,
1501 };
1502
1503 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1504         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1505         fsparam_u32     ("rmode",               Opt_rmode),
1506         fsparam_u32     ("fmode",               Opt_fmode),
1507         fsparam_u32     ("mode",                Opt_mode),
1508         fsparam_u32     ("uid",                 Opt_uid),
1509         fsparam_u32     ("gid",                 Opt_gid),
1510         {}
1511 };
1512
1513 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1514 {
1515         struct ffs_sb_fill_data *data = fc->fs_private;
1516         struct fs_parse_result result;
1517         int opt;
1518
1519         ENTER();
1520
1521         opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1522         if (opt < 0)
1523                 return opt;
1524
1525         switch (opt) {
1526         case Opt_no_disconnect:
1527                 data->no_disconnect = result.boolean;
1528                 break;
1529         case Opt_rmode:
1530                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1531                 break;
1532         case Opt_fmode:
1533                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1534                 break;
1535         case Opt_mode:
1536                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1537                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1538                 break;
1539
1540         case Opt_uid:
1541                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1542                 if (!uid_valid(data->perms.uid))
1543                         goto unmapped_value;
1544                 break;
1545         case Opt_gid:
1546                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1547                 if (!gid_valid(data->perms.gid))
1548                         goto unmapped_value;
1549                 break;
1550
1551         default:
1552                 return -ENOPARAM;
1553         }
1554
1555         return 0;
1556
1557 unmapped_value:
1558         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1559 }
1560
1561 /*
1562  * Set up the superblock for a mount.
1563  */
1564 static int ffs_fs_get_tree(struct fs_context *fc)
1565 {
1566         struct ffs_sb_fill_data *ctx = fc->fs_private;
1567         struct ffs_data *ffs;
1568         int ret;
1569
1570         ENTER();
1571
1572         if (!fc->source)
1573                 return invalf(fc, "No source specified");
1574
1575         ffs = ffs_data_new(fc->source);
1576         if (!ffs)
1577                 return -ENOMEM;
1578         ffs->file_perms = ctx->perms;
1579         ffs->no_disconnect = ctx->no_disconnect;
1580
1581         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1582         if (!ffs->dev_name) {
1583                 ffs_data_put(ffs);
1584                 return -ENOMEM;
1585         }
1586
1587         ret = ffs_acquire_dev(ffs->dev_name, ffs);
1588         if (ret) {
1589                 ffs_data_put(ffs);
1590                 return ret;
1591         }
1592
1593         ctx->ffs_data = ffs;
1594         return get_tree_nodev(fc, ffs_sb_fill);
1595 }
1596
1597 static void ffs_fs_free_fc(struct fs_context *fc)
1598 {
1599         struct ffs_sb_fill_data *ctx = fc->fs_private;
1600
1601         if (ctx) {
1602                 if (ctx->ffs_data) {
1603                         ffs_data_put(ctx->ffs_data);
1604                 }
1605
1606                 kfree(ctx);
1607         }
1608 }
1609
1610 static const struct fs_context_operations ffs_fs_context_ops = {
1611         .free           = ffs_fs_free_fc,
1612         .parse_param    = ffs_fs_parse_param,
1613         .get_tree       = ffs_fs_get_tree,
1614 };
1615
1616 static int ffs_fs_init_fs_context(struct fs_context *fc)
1617 {
1618         struct ffs_sb_fill_data *ctx;
1619
1620         ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1621         if (!ctx)
1622                 return -ENOMEM;
1623
1624         ctx->perms.mode = S_IFREG | 0600;
1625         ctx->perms.uid = GLOBAL_ROOT_UID;
1626         ctx->perms.gid = GLOBAL_ROOT_GID;
1627         ctx->root_mode = S_IFDIR | 0500;
1628         ctx->no_disconnect = false;
1629
1630         fc->fs_private = ctx;
1631         fc->ops = &ffs_fs_context_ops;
1632         return 0;
1633 }
1634
1635 static void
1636 ffs_fs_kill_sb(struct super_block *sb)
1637 {
1638         ENTER();
1639
1640         kill_litter_super(sb);
1641         if (sb->s_fs_info)
1642                 ffs_data_closed(sb->s_fs_info);
1643 }
1644
1645 static struct file_system_type ffs_fs_type = {
1646         .owner          = THIS_MODULE,
1647         .name           = "functionfs",
1648         .init_fs_context = ffs_fs_init_fs_context,
1649         .parameters     = ffs_fs_fs_parameters,
1650         .kill_sb        = ffs_fs_kill_sb,
1651 };
1652 MODULE_ALIAS_FS("functionfs");
1653
1654
1655 /* Driver's main init/cleanup functions *************************************/
1656
1657 static int functionfs_init(void)
1658 {
1659         int ret;
1660
1661         ENTER();
1662
1663         ret = register_filesystem(&ffs_fs_type);
1664         if (!ret)
1665                 pr_info("file system registered\n");
1666         else
1667                 pr_err("failed registering file system (%d)\n", ret);
1668
1669         return ret;
1670 }
1671
1672 static void functionfs_cleanup(void)
1673 {
1674         ENTER();
1675
1676         pr_info("unloading\n");
1677         unregister_filesystem(&ffs_fs_type);
1678 }
1679
1680
1681 /* ffs_data and ffs_function construction and destruction code **************/
1682
1683 static void ffs_data_clear(struct ffs_data *ffs);
1684 static void ffs_data_reset(struct ffs_data *ffs);
1685
1686 static void ffs_data_get(struct ffs_data *ffs)
1687 {
1688         ENTER();
1689
1690         refcount_inc(&ffs->ref);
1691 }
1692
1693 static void ffs_data_opened(struct ffs_data *ffs)
1694 {
1695         ENTER();
1696
1697         refcount_inc(&ffs->ref);
1698         if (atomic_add_return(1, &ffs->opened) == 1 &&
1699                         ffs->state == FFS_DEACTIVATED) {
1700                 ffs->state = FFS_CLOSING;
1701                 ffs_data_reset(ffs);
1702         }
1703 }
1704
1705 static void ffs_data_put(struct ffs_data *ffs)
1706 {
1707         ENTER();
1708
1709         if (refcount_dec_and_test(&ffs->ref)) {
1710                 pr_info("%s(): freeing\n", __func__);
1711                 ffs_data_clear(ffs);
1712                 ffs_release_dev(ffs->private_data);
1713                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1714                        swait_active(&ffs->ep0req_completion.wait) ||
1715                        waitqueue_active(&ffs->wait));
1716                 destroy_workqueue(ffs->io_completion_wq);
1717                 kfree(ffs->dev_name);
1718                 kfree(ffs);
1719         }
1720 }
1721
1722 static void ffs_data_closed(struct ffs_data *ffs)
1723 {
1724         struct ffs_epfile *epfiles;
1725         unsigned long flags;
1726
1727         ENTER();
1728
1729         if (atomic_dec_and_test(&ffs->opened)) {
1730                 if (ffs->no_disconnect) {
1731                         ffs->state = FFS_DEACTIVATED;
1732                         spin_lock_irqsave(&ffs->eps_lock, flags);
1733                         epfiles = ffs->epfiles;
1734                         ffs->epfiles = NULL;
1735                         spin_unlock_irqrestore(&ffs->eps_lock,
1736                                                         flags);
1737
1738                         if (epfiles)
1739                                 ffs_epfiles_destroy(epfiles,
1740                                                  ffs->eps_count);
1741
1742                         if (ffs->setup_state == FFS_SETUP_PENDING)
1743                                 __ffs_ep0_stall(ffs);
1744                 } else {
1745                         ffs->state = FFS_CLOSING;
1746                         ffs_data_reset(ffs);
1747                 }
1748         }
1749         if (atomic_read(&ffs->opened) < 0) {
1750                 ffs->state = FFS_CLOSING;
1751                 ffs_data_reset(ffs);
1752         }
1753
1754         ffs_data_put(ffs);
1755 }
1756
1757 static struct ffs_data *ffs_data_new(const char *dev_name)
1758 {
1759         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1760         if (!ffs)
1761                 return NULL;
1762
1763         ENTER();
1764
1765         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1766         if (!ffs->io_completion_wq) {
1767                 kfree(ffs);
1768                 return NULL;
1769         }
1770
1771         refcount_set(&ffs->ref, 1);
1772         atomic_set(&ffs->opened, 0);
1773         ffs->state = FFS_READ_DESCRIPTORS;
1774         mutex_init(&ffs->mutex);
1775         spin_lock_init(&ffs->eps_lock);
1776         init_waitqueue_head(&ffs->ev.waitq);
1777         init_waitqueue_head(&ffs->wait);
1778         init_completion(&ffs->ep0req_completion);
1779
1780         /* XXX REVISIT need to update it in some places, or do we? */
1781         ffs->ev.can_stall = 1;
1782
1783         return ffs;
1784 }
1785
1786 static void ffs_data_clear(struct ffs_data *ffs)
1787 {
1788         struct ffs_epfile *epfiles;
1789         unsigned long flags;
1790
1791         ENTER();
1792
1793         ffs_closed(ffs);
1794
1795         BUG_ON(ffs->gadget);
1796
1797         spin_lock_irqsave(&ffs->eps_lock, flags);
1798         epfiles = ffs->epfiles;
1799         ffs->epfiles = NULL;
1800         spin_unlock_irqrestore(&ffs->eps_lock, flags);
1801
1802         /*
1803          * potential race possible between ffs_func_eps_disable
1804          * & ffs_epfile_release therefore maintaining a local
1805          * copy of epfile will save us from use-after-free.
1806          */
1807         if (epfiles) {
1808                 ffs_epfiles_destroy(epfiles, ffs->eps_count);
1809                 ffs->epfiles = NULL;
1810         }
1811
1812         if (ffs->ffs_eventfd) {
1813                 eventfd_ctx_put(ffs->ffs_eventfd);
1814                 ffs->ffs_eventfd = NULL;
1815         }
1816
1817         kfree(ffs->raw_descs_data);
1818         kfree(ffs->raw_strings);
1819         kfree(ffs->stringtabs);
1820 }
1821
1822 static void ffs_data_reset(struct ffs_data *ffs)
1823 {
1824         ENTER();
1825
1826         ffs_data_clear(ffs);
1827
1828         ffs->raw_descs_data = NULL;
1829         ffs->raw_descs = NULL;
1830         ffs->raw_strings = NULL;
1831         ffs->stringtabs = NULL;
1832
1833         ffs->raw_descs_length = 0;
1834         ffs->fs_descs_count = 0;
1835         ffs->hs_descs_count = 0;
1836         ffs->ss_descs_count = 0;
1837
1838         ffs->strings_count = 0;
1839         ffs->interfaces_count = 0;
1840         ffs->eps_count = 0;
1841
1842         ffs->ev.count = 0;
1843
1844         ffs->state = FFS_READ_DESCRIPTORS;
1845         ffs->setup_state = FFS_NO_SETUP;
1846         ffs->flags = 0;
1847
1848         ffs->ms_os_descs_ext_prop_count = 0;
1849         ffs->ms_os_descs_ext_prop_name_len = 0;
1850         ffs->ms_os_descs_ext_prop_data_len = 0;
1851 }
1852
1853
1854 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1855 {
1856         struct usb_gadget_strings **lang;
1857         int first_id;
1858
1859         ENTER();
1860
1861         if (WARN_ON(ffs->state != FFS_ACTIVE
1862                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1863                 return -EBADFD;
1864
1865         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1866         if (first_id < 0)
1867                 return first_id;
1868
1869         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1870         if (!ffs->ep0req)
1871                 return -ENOMEM;
1872         ffs->ep0req->complete = ffs_ep0_complete;
1873         ffs->ep0req->context = ffs;
1874
1875         lang = ffs->stringtabs;
1876         if (lang) {
1877                 for (; *lang; ++lang) {
1878                         struct usb_string *str = (*lang)->strings;
1879                         int id = first_id;
1880                         for (; str->s; ++id, ++str)
1881                                 str->id = id;
1882                 }
1883         }
1884
1885         ffs->gadget = cdev->gadget;
1886         ffs_data_get(ffs);
1887         return 0;
1888 }
1889
1890 static void functionfs_unbind(struct ffs_data *ffs)
1891 {
1892         ENTER();
1893
1894         if (!WARN_ON(!ffs->gadget)) {
1895                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1896                 ffs->ep0req = NULL;
1897                 ffs->gadget = NULL;
1898                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1899                 ffs_data_put(ffs);
1900         }
1901 }
1902
1903 static int ffs_epfiles_create(struct ffs_data *ffs)
1904 {
1905         struct ffs_epfile *epfile, *epfiles;
1906         unsigned i, count;
1907
1908         ENTER();
1909
1910         count = ffs->eps_count;
1911         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1912         if (!epfiles)
1913                 return -ENOMEM;
1914
1915         epfile = epfiles;
1916         for (i = 1; i <= count; ++i, ++epfile) {
1917                 epfile->ffs = ffs;
1918                 mutex_init(&epfile->mutex);
1919                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1920                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1921                 else
1922                         sprintf(epfile->name, "ep%u", i);
1923                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1924                                                  epfile,
1925                                                  &ffs_epfile_operations);
1926                 if (!epfile->dentry) {
1927                         ffs_epfiles_destroy(epfiles, i - 1);
1928                         return -ENOMEM;
1929                 }
1930         }
1931
1932         ffs->epfiles = epfiles;
1933         return 0;
1934 }
1935
1936 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1937 {
1938         struct ffs_epfile *epfile = epfiles;
1939
1940         ENTER();
1941
1942         for (; count; --count, ++epfile) {
1943                 BUG_ON(mutex_is_locked(&epfile->mutex));
1944                 if (epfile->dentry) {
1945                         d_delete(epfile->dentry);
1946                         dput(epfile->dentry);
1947                         epfile->dentry = NULL;
1948                 }
1949         }
1950
1951         kfree(epfiles);
1952 }
1953
1954 static void ffs_func_eps_disable(struct ffs_function *func)
1955 {
1956         struct ffs_ep *ep;
1957         struct ffs_epfile *epfile;
1958         unsigned short count;
1959         unsigned long flags;
1960
1961         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1962         count = func->ffs->eps_count;
1963         epfile = func->ffs->epfiles;
1964         ep = func->eps;
1965         while (count--) {
1966                 /* pending requests get nuked */
1967                 if (ep->ep)
1968                         usb_ep_disable(ep->ep);
1969                 ++ep;
1970
1971                 if (epfile) {
1972                         epfile->ep = NULL;
1973                         __ffs_epfile_read_buffer_free(epfile);
1974                         ++epfile;
1975                 }
1976         }
1977         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1978 }
1979
1980 static int ffs_func_eps_enable(struct ffs_function *func)
1981 {
1982         struct ffs_data *ffs;
1983         struct ffs_ep *ep;
1984         struct ffs_epfile *epfile;
1985         unsigned short count;
1986         unsigned long flags;
1987         int ret = 0;
1988
1989         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1990         ffs = func->ffs;
1991         ep = func->eps;
1992         epfile = ffs->epfiles;
1993         count = ffs->eps_count;
1994         while(count--) {
1995                 ep->ep->driver_data = ep;
1996
1997                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1998                 if (ret) {
1999                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
2000                                         __func__, ep->ep->name, ret);
2001                         break;
2002                 }
2003
2004                 ret = usb_ep_enable(ep->ep);
2005                 if (!ret) {
2006                         epfile->ep = ep;
2007                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
2008                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
2009                 } else {
2010                         break;
2011                 }
2012
2013                 ++ep;
2014                 ++epfile;
2015         }
2016
2017         wake_up_interruptible(&ffs->wait);
2018         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2019
2020         return ret;
2021 }
2022
2023
2024 /* Parsing and building descriptors and strings *****************************/
2025
2026 /*
2027  * This validates if data pointed by data is a valid USB descriptor as
2028  * well as record how many interfaces, endpoints and strings are
2029  * required by given configuration.  Returns address after the
2030  * descriptor or NULL if data is invalid.
2031  */
2032
2033 enum ffs_entity_type {
2034         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
2035 };
2036
2037 enum ffs_os_desc_type {
2038         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
2039 };
2040
2041 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2042                                    u8 *valuep,
2043                                    struct usb_descriptor_header *desc,
2044                                    void *priv);
2045
2046 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2047                                     struct usb_os_desc_header *h, void *data,
2048                                     unsigned len, void *priv);
2049
2050 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2051                                            ffs_entity_callback entity,
2052                                            void *priv, int *current_class)
2053 {
2054         struct usb_descriptor_header *_ds = (void *)data;
2055         u8 length;
2056         int ret;
2057
2058         ENTER();
2059
2060         /* At least two bytes are required: length and type */
2061         if (len < 2) {
2062                 pr_vdebug("descriptor too short\n");
2063                 return -EINVAL;
2064         }
2065
2066         /* If we have at least as many bytes as the descriptor takes? */
2067         length = _ds->bLength;
2068         if (len < length) {
2069                 pr_vdebug("descriptor longer then available data\n");
2070                 return -EINVAL;
2071         }
2072
2073 #define __entity_check_INTERFACE(val)  1
2074 #define __entity_check_STRING(val)     (val)
2075 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2076 #define __entity(type, val) do {                                        \
2077                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2078                 if (!__entity_check_ ##type(val)) {                     \
2079                         pr_vdebug("invalid entity's value\n");          \
2080                         return -EINVAL;                                 \
2081                 }                                                       \
2082                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2083                 if (ret < 0) {                                          \
2084                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2085                                  (val), ret);                           \
2086                         return ret;                                     \
2087                 }                                                       \
2088         } while (0)
2089
2090         /* Parse descriptor depending on type. */
2091         switch (_ds->bDescriptorType) {
2092         case USB_DT_DEVICE:
2093         case USB_DT_CONFIG:
2094         case USB_DT_STRING:
2095         case USB_DT_DEVICE_QUALIFIER:
2096                 /* function can't have any of those */
2097                 pr_vdebug("descriptor reserved for gadget: %d\n",
2098                       _ds->bDescriptorType);
2099                 return -EINVAL;
2100
2101         case USB_DT_INTERFACE: {
2102                 struct usb_interface_descriptor *ds = (void *)_ds;
2103                 pr_vdebug("interface descriptor\n");
2104                 if (length != sizeof *ds)
2105                         goto inv_length;
2106
2107                 __entity(INTERFACE, ds->bInterfaceNumber);
2108                 if (ds->iInterface)
2109                         __entity(STRING, ds->iInterface);
2110                 *current_class = ds->bInterfaceClass;
2111         }
2112                 break;
2113
2114         case USB_DT_ENDPOINT: {
2115                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2116                 pr_vdebug("endpoint descriptor\n");
2117                 if (length != USB_DT_ENDPOINT_SIZE &&
2118                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2119                         goto inv_length;
2120                 __entity(ENDPOINT, ds->bEndpointAddress);
2121         }
2122                 break;
2123
2124         case USB_TYPE_CLASS | 0x01:
2125                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2126                         pr_vdebug("hid descriptor\n");
2127                         if (length != sizeof(struct hid_descriptor))
2128                                 goto inv_length;
2129                         break;
2130                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2131                         pr_vdebug("ccid descriptor\n");
2132                         if (length != sizeof(struct ccid_descriptor))
2133                                 goto inv_length;
2134                         break;
2135                 } else {
2136                         pr_vdebug("unknown descriptor: %d for class %d\n",
2137                               _ds->bDescriptorType, *current_class);
2138                         return -EINVAL;
2139                 }
2140
2141         case USB_DT_OTG:
2142                 if (length != sizeof(struct usb_otg_descriptor))
2143                         goto inv_length;
2144                 break;
2145
2146         case USB_DT_INTERFACE_ASSOCIATION: {
2147                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2148                 pr_vdebug("interface association descriptor\n");
2149                 if (length != sizeof *ds)
2150                         goto inv_length;
2151                 if (ds->iFunction)
2152                         __entity(STRING, ds->iFunction);
2153         }
2154                 break;
2155
2156         case USB_DT_SS_ENDPOINT_COMP:
2157                 pr_vdebug("EP SS companion descriptor\n");
2158                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2159                         goto inv_length;
2160                 break;
2161
2162         case USB_DT_OTHER_SPEED_CONFIG:
2163         case USB_DT_INTERFACE_POWER:
2164         case USB_DT_DEBUG:
2165         case USB_DT_SECURITY:
2166         case USB_DT_CS_RADIO_CONTROL:
2167                 /* TODO */
2168                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2169                 return -EINVAL;
2170
2171         default:
2172                 /* We should never be here */
2173                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2174                 return -EINVAL;
2175
2176 inv_length:
2177                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2178                           _ds->bLength, _ds->bDescriptorType);
2179                 return -EINVAL;
2180         }
2181
2182 #undef __entity
2183 #undef __entity_check_DESCRIPTOR
2184 #undef __entity_check_INTERFACE
2185 #undef __entity_check_STRING
2186 #undef __entity_check_ENDPOINT
2187
2188         return length;
2189 }
2190
2191 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2192                                      ffs_entity_callback entity, void *priv)
2193 {
2194         const unsigned _len = len;
2195         unsigned long num = 0;
2196         int current_class = -1;
2197
2198         ENTER();
2199
2200         for (;;) {
2201                 int ret;
2202
2203                 if (num == count)
2204                         data = NULL;
2205
2206                 /* Record "descriptor" entity */
2207                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2208                 if (ret < 0) {
2209                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2210                                  num, ret);
2211                         return ret;
2212                 }
2213
2214                 if (!data)
2215                         return _len - len;
2216
2217                 ret = ffs_do_single_desc(data, len, entity, priv,
2218                         &current_class);
2219                 if (ret < 0) {
2220                         pr_debug("%s returns %d\n", __func__, ret);
2221                         return ret;
2222                 }
2223
2224                 len -= ret;
2225                 data += ret;
2226                 ++num;
2227         }
2228 }
2229
2230 static int __ffs_data_do_entity(enum ffs_entity_type type,
2231                                 u8 *valuep, struct usb_descriptor_header *desc,
2232                                 void *priv)
2233 {
2234         struct ffs_desc_helper *helper = priv;
2235         struct usb_endpoint_descriptor *d;
2236
2237         ENTER();
2238
2239         switch (type) {
2240         case FFS_DESCRIPTOR:
2241                 break;
2242
2243         case FFS_INTERFACE:
2244                 /*
2245                  * Interfaces are indexed from zero so if we
2246                  * encountered interface "n" then there are at least
2247                  * "n+1" interfaces.
2248                  */
2249                 if (*valuep >= helper->interfaces_count)
2250                         helper->interfaces_count = *valuep + 1;
2251                 break;
2252
2253         case FFS_STRING:
2254                 /*
2255                  * Strings are indexed from 1 (0 is reserved
2256                  * for languages list)
2257                  */
2258                 if (*valuep > helper->ffs->strings_count)
2259                         helper->ffs->strings_count = *valuep;
2260                 break;
2261
2262         case FFS_ENDPOINT:
2263                 d = (void *)desc;
2264                 helper->eps_count++;
2265                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2266                         return -EINVAL;
2267                 /* Check if descriptors for any speed were already parsed */
2268                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2269                         helper->ffs->eps_addrmap[helper->eps_count] =
2270                                 d->bEndpointAddress;
2271                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2272                                 d->bEndpointAddress)
2273                         return -EINVAL;
2274                 break;
2275         }
2276
2277         return 0;
2278 }
2279
2280 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2281                                    struct usb_os_desc_header *desc)
2282 {
2283         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2284         u16 w_index = le16_to_cpu(desc->wIndex);
2285
2286         if (bcd_version != 1) {
2287                 pr_vdebug("unsupported os descriptors version: %d",
2288                           bcd_version);
2289                 return -EINVAL;
2290         }
2291         switch (w_index) {
2292         case 0x4:
2293                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2294                 break;
2295         case 0x5:
2296                 *next_type = FFS_OS_DESC_EXT_PROP;
2297                 break;
2298         default:
2299                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2300                 return -EINVAL;
2301         }
2302
2303         return sizeof(*desc);
2304 }
2305
2306 /*
2307  * Process all extended compatibility/extended property descriptors
2308  * of a feature descriptor
2309  */
2310 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2311                                               enum ffs_os_desc_type type,
2312                                               u16 feature_count,
2313                                               ffs_os_desc_callback entity,
2314                                               void *priv,
2315                                               struct usb_os_desc_header *h)
2316 {
2317         int ret;
2318         const unsigned _len = len;
2319
2320         ENTER();
2321
2322         /* loop over all ext compat/ext prop descriptors */
2323         while (feature_count--) {
2324                 ret = entity(type, h, data, len, priv);
2325                 if (ret < 0) {
2326                         pr_debug("bad OS descriptor, type: %d\n", type);
2327                         return ret;
2328                 }
2329                 data += ret;
2330                 len -= ret;
2331         }
2332         return _len - len;
2333 }
2334
2335 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2336 static int __must_check ffs_do_os_descs(unsigned count,
2337                                         char *data, unsigned len,
2338                                         ffs_os_desc_callback entity, void *priv)
2339 {
2340         const unsigned _len = len;
2341         unsigned long num = 0;
2342
2343         ENTER();
2344
2345         for (num = 0; num < count; ++num) {
2346                 int ret;
2347                 enum ffs_os_desc_type type;
2348                 u16 feature_count;
2349                 struct usb_os_desc_header *desc = (void *)data;
2350
2351                 if (len < sizeof(*desc))
2352                         return -EINVAL;
2353
2354                 /*
2355                  * Record "descriptor" entity.
2356                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2357                  * Move the data pointer to the beginning of extended
2358                  * compatibilities proper or extended properties proper
2359                  * portions of the data
2360                  */
2361                 if (le32_to_cpu(desc->dwLength) > len)
2362                         return -EINVAL;
2363
2364                 ret = __ffs_do_os_desc_header(&type, desc);
2365                 if (ret < 0) {
2366                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2367                                  num, ret);
2368                         return ret;
2369                 }
2370                 /*
2371                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2372                  */
2373                 feature_count = le16_to_cpu(desc->wCount);
2374                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2375                     (feature_count > 255 || desc->Reserved))
2376                                 return -EINVAL;
2377                 len -= ret;
2378                 data += ret;
2379
2380                 /*
2381                  * Process all function/property descriptors
2382                  * of this Feature Descriptor
2383                  */
2384                 ret = ffs_do_single_os_desc(data, len, type,
2385                                             feature_count, entity, priv, desc);
2386                 if (ret < 0) {
2387                         pr_debug("%s returns %d\n", __func__, ret);
2388                         return ret;
2389                 }
2390
2391                 len -= ret;
2392                 data += ret;
2393         }
2394         return _len - len;
2395 }
2396
2397 /*
2398  * Validate contents of the buffer from userspace related to OS descriptors.
2399  */
2400 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2401                                  struct usb_os_desc_header *h, void *data,
2402                                  unsigned len, void *priv)
2403 {
2404         struct ffs_data *ffs = priv;
2405         u8 length;
2406
2407         ENTER();
2408
2409         switch (type) {
2410         case FFS_OS_DESC_EXT_COMPAT: {
2411                 struct usb_ext_compat_desc *d = data;
2412                 int i;
2413
2414                 if (len < sizeof(*d) ||
2415                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2416                         return -EINVAL;
2417                 if (d->Reserved1 != 1) {
2418                         /*
2419                          * According to the spec, Reserved1 must be set to 1
2420                          * but older kernels incorrectly rejected non-zero
2421                          * values.  We fix it here to avoid returning EINVAL
2422                          * in response to values we used to accept.
2423                          */
2424                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2425                         d->Reserved1 = 1;
2426                 }
2427                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2428                         if (d->Reserved2[i])
2429                                 return -EINVAL;
2430
2431                 length = sizeof(struct usb_ext_compat_desc);
2432         }
2433                 break;
2434         case FFS_OS_DESC_EXT_PROP: {
2435                 struct usb_ext_prop_desc *d = data;
2436                 u32 type, pdl;
2437                 u16 pnl;
2438
2439                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2440                         return -EINVAL;
2441                 length = le32_to_cpu(d->dwSize);
2442                 if (len < length)
2443                         return -EINVAL;
2444                 type = le32_to_cpu(d->dwPropertyDataType);
2445                 if (type < USB_EXT_PROP_UNICODE ||
2446                     type > USB_EXT_PROP_UNICODE_MULTI) {
2447                         pr_vdebug("unsupported os descriptor property type: %d",
2448                                   type);
2449                         return -EINVAL;
2450                 }
2451                 pnl = le16_to_cpu(d->wPropertyNameLength);
2452                 if (length < 14 + pnl) {
2453                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2454                                   length, pnl, type);
2455                         return -EINVAL;
2456                 }
2457                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2458                 if (length != 14 + pnl + pdl) {
2459                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2460                                   length, pnl, pdl, type);
2461                         return -EINVAL;
2462                 }
2463                 ++ffs->ms_os_descs_ext_prop_count;
2464                 /* property name reported to the host as "WCHAR"s */
2465                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2466                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2467         }
2468                 break;
2469         default:
2470                 pr_vdebug("unknown descriptor: %d\n", type);
2471                 return -EINVAL;
2472         }
2473         return length;
2474 }
2475
2476 static int __ffs_data_got_descs(struct ffs_data *ffs,
2477                                 char *const _data, size_t len)
2478 {
2479         char *data = _data, *raw_descs;
2480         unsigned os_descs_count = 0, counts[3], flags;
2481         int ret = -EINVAL, i;
2482         struct ffs_desc_helper helper;
2483
2484         ENTER();
2485
2486         if (get_unaligned_le32(data + 4) != len)
2487                 goto error;
2488
2489         switch (get_unaligned_le32(data)) {
2490         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2491                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2492                 data += 8;
2493                 len  -= 8;
2494                 break;
2495         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2496                 flags = get_unaligned_le32(data + 8);
2497                 ffs->user_flags = flags;
2498                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2499                               FUNCTIONFS_HAS_HS_DESC |
2500                               FUNCTIONFS_HAS_SS_DESC |
2501                               FUNCTIONFS_HAS_MS_OS_DESC |
2502                               FUNCTIONFS_VIRTUAL_ADDR |
2503                               FUNCTIONFS_EVENTFD |
2504                               FUNCTIONFS_ALL_CTRL_RECIP |
2505                               FUNCTIONFS_CONFIG0_SETUP)) {
2506                         ret = -ENOSYS;
2507                         goto error;
2508                 }
2509                 data += 12;
2510                 len  -= 12;
2511                 break;
2512         default:
2513                 goto error;
2514         }
2515
2516         if (flags & FUNCTIONFS_EVENTFD) {
2517                 if (len < 4)
2518                         goto error;
2519                 ffs->ffs_eventfd =
2520                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2521                 if (IS_ERR(ffs->ffs_eventfd)) {
2522                         ret = PTR_ERR(ffs->ffs_eventfd);
2523                         ffs->ffs_eventfd = NULL;
2524                         goto error;
2525                 }
2526                 data += 4;
2527                 len  -= 4;
2528         }
2529
2530         /* Read fs_count, hs_count and ss_count (if present) */
2531         for (i = 0; i < 3; ++i) {
2532                 if (!(flags & (1 << i))) {
2533                         counts[i] = 0;
2534                 } else if (len < 4) {
2535                         goto error;
2536                 } else {
2537                         counts[i] = get_unaligned_le32(data);
2538                         data += 4;
2539                         len  -= 4;
2540                 }
2541         }
2542         if (flags & (1 << i)) {
2543                 if (len < 4) {
2544                         goto error;
2545                 }
2546                 os_descs_count = get_unaligned_le32(data);
2547                 data += 4;
2548                 len -= 4;
2549         }
2550
2551         /* Read descriptors */
2552         raw_descs = data;
2553         helper.ffs = ffs;
2554         for (i = 0; i < 3; ++i) {
2555                 if (!counts[i])
2556                         continue;
2557                 helper.interfaces_count = 0;
2558                 helper.eps_count = 0;
2559                 ret = ffs_do_descs(counts[i], data, len,
2560                                    __ffs_data_do_entity, &helper);
2561                 if (ret < 0)
2562                         goto error;
2563                 if (!ffs->eps_count && !ffs->interfaces_count) {
2564                         ffs->eps_count = helper.eps_count;
2565                         ffs->interfaces_count = helper.interfaces_count;
2566                 } else {
2567                         if (ffs->eps_count != helper.eps_count) {
2568                                 ret = -EINVAL;
2569                                 goto error;
2570                         }
2571                         if (ffs->interfaces_count != helper.interfaces_count) {
2572                                 ret = -EINVAL;
2573                                 goto error;
2574                         }
2575                 }
2576                 data += ret;
2577                 len  -= ret;
2578         }
2579         if (os_descs_count) {
2580                 ret = ffs_do_os_descs(os_descs_count, data, len,
2581                                       __ffs_data_do_os_desc, ffs);
2582                 if (ret < 0)
2583                         goto error;
2584                 data += ret;
2585                 len -= ret;
2586         }
2587
2588         if (raw_descs == data || len) {
2589                 ret = -EINVAL;
2590                 goto error;
2591         }
2592
2593         ffs->raw_descs_data     = _data;
2594         ffs->raw_descs          = raw_descs;
2595         ffs->raw_descs_length   = data - raw_descs;
2596         ffs->fs_descs_count     = counts[0];
2597         ffs->hs_descs_count     = counts[1];
2598         ffs->ss_descs_count     = counts[2];
2599         ffs->ms_os_descs_count  = os_descs_count;
2600
2601         return 0;
2602
2603 error:
2604         kfree(_data);
2605         return ret;
2606 }
2607
2608 static int __ffs_data_got_strings(struct ffs_data *ffs,
2609                                   char *const _data, size_t len)
2610 {
2611         u32 str_count, needed_count, lang_count;
2612         struct usb_gadget_strings **stringtabs, *t;
2613         const char *data = _data;
2614         struct usb_string *s;
2615
2616         ENTER();
2617
2618         if (len < 16 ||
2619             get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2620             get_unaligned_le32(data + 4) != len)
2621                 goto error;
2622         str_count  = get_unaligned_le32(data + 8);
2623         lang_count = get_unaligned_le32(data + 12);
2624
2625         /* if one is zero the other must be zero */
2626         if (!str_count != !lang_count)
2627                 goto error;
2628
2629         /* Do we have at least as many strings as descriptors need? */
2630         needed_count = ffs->strings_count;
2631         if (str_count < needed_count)
2632                 goto error;
2633
2634         /*
2635          * If we don't need any strings just return and free all
2636          * memory.
2637          */
2638         if (!needed_count) {
2639                 kfree(_data);
2640                 return 0;
2641         }
2642
2643         /* Allocate everything in one chunk so there's less maintenance. */
2644         {
2645                 unsigned i = 0;
2646                 vla_group(d);
2647                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2648                         lang_count + 1);
2649                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2650                 vla_item(d, struct usb_string, strings,
2651                         lang_count*(needed_count+1));
2652
2653                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2654
2655                 if (!vlabuf) {
2656                         kfree(_data);
2657                         return -ENOMEM;
2658                 }
2659
2660                 /* Initialize the VLA pointers */
2661                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2662                 t = vla_ptr(vlabuf, d, stringtab);
2663                 i = lang_count;
2664                 do {
2665                         *stringtabs++ = t++;
2666                 } while (--i);
2667                 *stringtabs = NULL;
2668
2669                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2670                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2671                 t = vla_ptr(vlabuf, d, stringtab);
2672                 s = vla_ptr(vlabuf, d, strings);
2673         }
2674
2675         /* For each language */
2676         data += 16;
2677         len -= 16;
2678
2679         do { /* lang_count > 0 so we can use do-while */
2680                 unsigned needed = needed_count;
2681                 u32 str_per_lang = str_count;
2682
2683                 if (len < 3)
2684                         goto error_free;
2685                 t->language = get_unaligned_le16(data);
2686                 t->strings  = s;
2687                 ++t;
2688
2689                 data += 2;
2690                 len -= 2;
2691
2692                 /* For each string */
2693                 do { /* str_count > 0 so we can use do-while */
2694                         size_t length = strnlen(data, len);
2695
2696                         if (length == len)
2697                                 goto error_free;
2698
2699                         /*
2700                          * User may provide more strings then we need,
2701                          * if that's the case we simply ignore the
2702                          * rest
2703                          */
2704                         if (needed) {
2705                                 /*
2706                                  * s->id will be set while adding
2707                                  * function to configuration so for
2708                                  * now just leave garbage here.
2709                                  */
2710                                 s->s = data;
2711                                 --needed;
2712                                 ++s;
2713                         }
2714
2715                         data += length + 1;
2716                         len -= length + 1;
2717                 } while (--str_per_lang);
2718
2719                 s->id = 0;   /* terminator */
2720                 s->s = NULL;
2721                 ++s;
2722
2723         } while (--lang_count);
2724
2725         /* Some garbage left? */
2726         if (len)
2727                 goto error_free;
2728
2729         /* Done! */
2730         ffs->stringtabs = stringtabs;
2731         ffs->raw_strings = _data;
2732
2733         return 0;
2734
2735 error_free:
2736         kfree(stringtabs);
2737 error:
2738         kfree(_data);
2739         return -EINVAL;
2740 }
2741
2742
2743 /* Events handling and management *******************************************/
2744
2745 static void __ffs_event_add(struct ffs_data *ffs,
2746                             enum usb_functionfs_event_type type)
2747 {
2748         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2749         int neg = 0;
2750
2751         /*
2752          * Abort any unhandled setup
2753          *
2754          * We do not need to worry about some cmpxchg() changing value
2755          * of ffs->setup_state without holding the lock because when
2756          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2757          * the source does nothing.
2758          */
2759         if (ffs->setup_state == FFS_SETUP_PENDING)
2760                 ffs->setup_state = FFS_SETUP_CANCELLED;
2761
2762         /*
2763          * Logic of this function guarantees that there are at most four pending
2764          * evens on ffs->ev.types queue.  This is important because the queue
2765          * has space for four elements only and __ffs_ep0_read_events function
2766          * depends on that limit as well.  If more event types are added, those
2767          * limits have to be revisited or guaranteed to still hold.
2768          */
2769         switch (type) {
2770         case FUNCTIONFS_RESUME:
2771                 rem_type2 = FUNCTIONFS_SUSPEND;
2772                 fallthrough;
2773         case FUNCTIONFS_SUSPEND:
2774         case FUNCTIONFS_SETUP:
2775                 rem_type1 = type;
2776                 /* Discard all similar events */
2777                 break;
2778
2779         case FUNCTIONFS_BIND:
2780         case FUNCTIONFS_UNBIND:
2781         case FUNCTIONFS_DISABLE:
2782         case FUNCTIONFS_ENABLE:
2783                 /* Discard everything other then power management. */
2784                 rem_type1 = FUNCTIONFS_SUSPEND;
2785                 rem_type2 = FUNCTIONFS_RESUME;
2786                 neg = 1;
2787                 break;
2788
2789         default:
2790                 WARN(1, "%d: unknown event, this should not happen\n", type);
2791                 return;
2792         }
2793
2794         {
2795                 u8 *ev  = ffs->ev.types, *out = ev;
2796                 unsigned n = ffs->ev.count;
2797                 for (; n; --n, ++ev)
2798                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2799                                 *out++ = *ev;
2800                         else
2801                                 pr_vdebug("purging event %d\n", *ev);
2802                 ffs->ev.count = out - ffs->ev.types;
2803         }
2804
2805         pr_vdebug("adding event %d\n", type);
2806         ffs->ev.types[ffs->ev.count++] = type;
2807         wake_up_locked(&ffs->ev.waitq);
2808         if (ffs->ffs_eventfd)
2809                 eventfd_signal(ffs->ffs_eventfd, 1);
2810 }
2811
2812 static void ffs_event_add(struct ffs_data *ffs,
2813                           enum usb_functionfs_event_type type)
2814 {
2815         unsigned long flags;
2816         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2817         __ffs_event_add(ffs, type);
2818         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2819 }
2820
2821 /* Bind/unbind USB function hooks *******************************************/
2822
2823 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2824 {
2825         int i;
2826
2827         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2828                 if (ffs->eps_addrmap[i] == endpoint_address)
2829                         return i;
2830         return -ENOENT;
2831 }
2832
2833 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2834                                     struct usb_descriptor_header *desc,
2835                                     void *priv)
2836 {
2837         struct usb_endpoint_descriptor *ds = (void *)desc;
2838         struct ffs_function *func = priv;
2839         struct ffs_ep *ffs_ep;
2840         unsigned ep_desc_id;
2841         int idx;
2842         static const char *speed_names[] = { "full", "high", "super" };
2843
2844         if (type != FFS_DESCRIPTOR)
2845                 return 0;
2846
2847         /*
2848          * If ss_descriptors is not NULL, we are reading super speed
2849          * descriptors; if hs_descriptors is not NULL, we are reading high
2850          * speed descriptors; otherwise, we are reading full speed
2851          * descriptors.
2852          */
2853         if (func->function.ss_descriptors) {
2854                 ep_desc_id = 2;
2855                 func->function.ss_descriptors[(long)valuep] = desc;
2856         } else if (func->function.hs_descriptors) {
2857                 ep_desc_id = 1;
2858                 func->function.hs_descriptors[(long)valuep] = desc;
2859         } else {
2860                 ep_desc_id = 0;
2861                 func->function.fs_descriptors[(long)valuep]    = desc;
2862         }
2863
2864         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2865                 return 0;
2866
2867         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2868         if (idx < 0)
2869                 return idx;
2870
2871         ffs_ep = func->eps + idx;
2872
2873         if (ffs_ep->descs[ep_desc_id]) {
2874                 pr_err("two %sspeed descriptors for EP %d\n",
2875                           speed_names[ep_desc_id],
2876                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2877                 return -EINVAL;
2878         }
2879         ffs_ep->descs[ep_desc_id] = ds;
2880
2881         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2882         if (ffs_ep->ep) {
2883                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2884                 if (!ds->wMaxPacketSize)
2885                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2886         } else {
2887                 struct usb_request *req;
2888                 struct usb_ep *ep;
2889                 u8 bEndpointAddress;
2890                 u16 wMaxPacketSize;
2891
2892                 /*
2893                  * We back up bEndpointAddress because autoconfig overwrites
2894                  * it with physical endpoint address.
2895                  */
2896                 bEndpointAddress = ds->bEndpointAddress;
2897                 /*
2898                  * We back up wMaxPacketSize because autoconfig treats
2899                  * endpoint descriptors as if they were full speed.
2900                  */
2901                 wMaxPacketSize = ds->wMaxPacketSize;
2902                 pr_vdebug("autoconfig\n");
2903                 ep = usb_ep_autoconfig(func->gadget, ds);
2904                 if (!ep)
2905                         return -ENOTSUPP;
2906                 ep->driver_data = func->eps + idx;
2907
2908                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2909                 if (!req)
2910                         return -ENOMEM;
2911
2912                 ffs_ep->ep  = ep;
2913                 ffs_ep->req = req;
2914                 func->eps_revmap[ds->bEndpointAddress &
2915                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2916                 /*
2917                  * If we use virtual address mapping, we restore
2918                  * original bEndpointAddress value.
2919                  */
2920                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2921                         ds->bEndpointAddress = bEndpointAddress;
2922                 /*
2923                  * Restore wMaxPacketSize which was potentially
2924                  * overwritten by autoconfig.
2925                  */
2926                 ds->wMaxPacketSize = wMaxPacketSize;
2927         }
2928         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2929
2930         return 0;
2931 }
2932
2933 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2934                                    struct usb_descriptor_header *desc,
2935                                    void *priv)
2936 {
2937         struct ffs_function *func = priv;
2938         unsigned idx;
2939         u8 newValue;
2940
2941         switch (type) {
2942         default:
2943         case FFS_DESCRIPTOR:
2944                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2945                 return 0;
2946
2947         case FFS_INTERFACE:
2948                 idx = *valuep;
2949                 if (func->interfaces_nums[idx] < 0) {
2950                         int id = usb_interface_id(func->conf, &func->function);
2951                         if (id < 0)
2952                                 return id;
2953                         func->interfaces_nums[idx] = id;
2954                 }
2955                 newValue = func->interfaces_nums[idx];
2956                 break;
2957
2958         case FFS_STRING:
2959                 /* String' IDs are allocated when fsf_data is bound to cdev */
2960                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2961                 break;
2962
2963         case FFS_ENDPOINT:
2964                 /*
2965                  * USB_DT_ENDPOINT are handled in
2966                  * __ffs_func_bind_do_descs().
2967                  */
2968                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2969                         return 0;
2970
2971                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2972                 if (!func->eps[idx].ep)
2973                         return -EINVAL;
2974
2975                 {
2976                         struct usb_endpoint_descriptor **descs;
2977                         descs = func->eps[idx].descs;
2978                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2979                 }
2980                 break;
2981         }
2982
2983         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2984         *valuep = newValue;
2985         return 0;
2986 }
2987
2988 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2989                                       struct usb_os_desc_header *h, void *data,
2990                                       unsigned len, void *priv)
2991 {
2992         struct ffs_function *func = priv;
2993         u8 length = 0;
2994
2995         switch (type) {
2996         case FFS_OS_DESC_EXT_COMPAT: {
2997                 struct usb_ext_compat_desc *desc = data;
2998                 struct usb_os_desc_table *t;
2999
3000                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
3001                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
3002                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
3003                        ARRAY_SIZE(desc->CompatibleID) +
3004                        ARRAY_SIZE(desc->SubCompatibleID));
3005                 length = sizeof(*desc);
3006         }
3007                 break;
3008         case FFS_OS_DESC_EXT_PROP: {
3009                 struct usb_ext_prop_desc *desc = data;
3010                 struct usb_os_desc_table *t;
3011                 struct usb_os_desc_ext_prop *ext_prop;
3012                 char *ext_prop_name;
3013                 char *ext_prop_data;
3014
3015                 t = &func->function.os_desc_table[h->interface];
3016                 t->if_id = func->interfaces_nums[h->interface];
3017
3018                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
3019                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
3020
3021                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
3022                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
3023                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
3024                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
3025                 length = ext_prop->name_len + ext_prop->data_len + 14;
3026
3027                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
3028                 func->ffs->ms_os_descs_ext_prop_name_avail +=
3029                         ext_prop->name_len;
3030
3031                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
3032                 func->ffs->ms_os_descs_ext_prop_data_avail +=
3033                         ext_prop->data_len;
3034                 memcpy(ext_prop_data,
3035                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
3036                        ext_prop->data_len);
3037                 /* unicode data reported to the host as "WCHAR"s */
3038                 switch (ext_prop->type) {
3039                 case USB_EXT_PROP_UNICODE:
3040                 case USB_EXT_PROP_UNICODE_ENV:
3041                 case USB_EXT_PROP_UNICODE_LINK:
3042                 case USB_EXT_PROP_UNICODE_MULTI:
3043                         ext_prop->data_len *= 2;
3044                         break;
3045                 }
3046                 ext_prop->data = ext_prop_data;
3047
3048                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3049                        ext_prop->name_len);
3050                 /* property name reported to the host as "WCHAR"s */
3051                 ext_prop->name_len *= 2;
3052                 ext_prop->name = ext_prop_name;
3053
3054                 t->os_desc->ext_prop_len +=
3055                         ext_prop->name_len + ext_prop->data_len + 14;
3056                 ++t->os_desc->ext_prop_count;
3057                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3058         }
3059                 break;
3060         default:
3061                 pr_vdebug("unknown descriptor: %d\n", type);
3062         }
3063
3064         return length;
3065 }
3066
3067 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3068                                                 struct usb_configuration *c)
3069 {
3070         struct ffs_function *func = ffs_func_from_usb(f);
3071         struct f_fs_opts *ffs_opts =
3072                 container_of(f->fi, struct f_fs_opts, func_inst);
3073         struct ffs_data *ffs_data;
3074         int ret;
3075
3076         ENTER();
3077
3078         /*
3079          * Legacy gadget triggers binding in functionfs_ready_callback,
3080          * which already uses locking; taking the same lock here would
3081          * cause a deadlock.
3082          *
3083          * Configfs-enabled gadgets however do need ffs_dev_lock.
3084          */
3085         if (!ffs_opts->no_configfs)
3086                 ffs_dev_lock();
3087         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3088         ffs_data = ffs_opts->dev->ffs_data;
3089         if (!ffs_opts->no_configfs)
3090                 ffs_dev_unlock();
3091         if (ret)
3092                 return ERR_PTR(ret);
3093
3094         func->ffs = ffs_data;
3095         func->conf = c;
3096         func->gadget = c->cdev->gadget;
3097
3098         /*
3099          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3100          * configurations are bound in sequence with list_for_each_entry,
3101          * in each configuration its functions are bound in sequence
3102          * with list_for_each_entry, so we assume no race condition
3103          * with regard to ffs_opts->bound access
3104          */
3105         if (!ffs_opts->refcnt) {
3106                 ret = functionfs_bind(func->ffs, c->cdev);
3107                 if (ret)
3108                         return ERR_PTR(ret);
3109         }
3110         ffs_opts->refcnt++;
3111         func->function.strings = func->ffs->stringtabs;
3112
3113         return ffs_opts;
3114 }
3115
3116 static int _ffs_func_bind(struct usb_configuration *c,
3117                           struct usb_function *f)
3118 {
3119         struct ffs_function *func = ffs_func_from_usb(f);
3120         struct ffs_data *ffs = func->ffs;
3121
3122         const int full = !!func->ffs->fs_descs_count;
3123         const int high = !!func->ffs->hs_descs_count;
3124         const int super = !!func->ffs->ss_descs_count;
3125
3126         int fs_len, hs_len, ss_len, ret, i;
3127         struct ffs_ep *eps_ptr;
3128
3129         /* Make it a single chunk, less management later on */
3130         vla_group(d);
3131         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3132         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3133                 full ? ffs->fs_descs_count + 1 : 0);
3134         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3135                 high ? ffs->hs_descs_count + 1 : 0);
3136         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3137                 super ? ffs->ss_descs_count + 1 : 0);
3138         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3139         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3140                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3141         vla_item_with_sz(d, char[16], ext_compat,
3142                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3143         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3144                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3145         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3146                          ffs->ms_os_descs_ext_prop_count);
3147         vla_item_with_sz(d, char, ext_prop_name,
3148                          ffs->ms_os_descs_ext_prop_name_len);
3149         vla_item_with_sz(d, char, ext_prop_data,
3150                          ffs->ms_os_descs_ext_prop_data_len);
3151         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3152         char *vlabuf;
3153
3154         ENTER();
3155
3156         /* Has descriptors only for speeds gadget does not support */
3157         if (!(full | high | super))
3158                 return -ENOTSUPP;
3159
3160         /* Allocate a single chunk, less management later on */
3161         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3162         if (!vlabuf)
3163                 return -ENOMEM;
3164
3165         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3166         ffs->ms_os_descs_ext_prop_name_avail =
3167                 vla_ptr(vlabuf, d, ext_prop_name);
3168         ffs->ms_os_descs_ext_prop_data_avail =
3169                 vla_ptr(vlabuf, d, ext_prop_data);
3170
3171         /* Copy descriptors  */
3172         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3173                ffs->raw_descs_length);
3174
3175         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3176         eps_ptr = vla_ptr(vlabuf, d, eps);
3177         for (i = 0; i < ffs->eps_count; i++)
3178                 eps_ptr[i].num = -1;
3179
3180         /* Save pointers
3181          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3182         */
3183         func->eps             = vla_ptr(vlabuf, d, eps);
3184         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3185
3186         /*
3187          * Go through all the endpoint descriptors and allocate
3188          * endpoints first, so that later we can rewrite the endpoint
3189          * numbers without worrying that it may be described later on.
3190          */
3191         if (full) {
3192                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3193                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3194                                       vla_ptr(vlabuf, d, raw_descs),
3195                                       d_raw_descs__sz,
3196                                       __ffs_func_bind_do_descs, func);
3197                 if (fs_len < 0) {
3198                         ret = fs_len;
3199                         goto error;
3200                 }
3201         } else {
3202                 fs_len = 0;
3203         }
3204
3205         if (high) {
3206                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3207                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3208                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3209                                       d_raw_descs__sz - fs_len,
3210                                       __ffs_func_bind_do_descs, func);
3211                 if (hs_len < 0) {
3212                         ret = hs_len;
3213                         goto error;
3214                 }
3215         } else {
3216                 hs_len = 0;
3217         }
3218
3219         if (super) {
3220                 func->function.ss_descriptors = func->function.ssp_descriptors =
3221                         vla_ptr(vlabuf, d, ss_descs);
3222                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3223                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3224                                 d_raw_descs__sz - fs_len - hs_len,
3225                                 __ffs_func_bind_do_descs, func);
3226                 if (ss_len < 0) {
3227                         ret = ss_len;
3228                         goto error;
3229                 }
3230         } else {
3231                 ss_len = 0;
3232         }
3233
3234         /*
3235          * Now handle interface numbers allocation and interface and
3236          * endpoint numbers rewriting.  We can do that in one go
3237          * now.
3238          */
3239         ret = ffs_do_descs(ffs->fs_descs_count +
3240                            (high ? ffs->hs_descs_count : 0) +
3241                            (super ? ffs->ss_descs_count : 0),
3242                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3243                            __ffs_func_bind_do_nums, func);
3244         if (ret < 0)
3245                 goto error;
3246
3247         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3248         if (c->cdev->use_os_string) {
3249                 for (i = 0; i < ffs->interfaces_count; ++i) {
3250                         struct usb_os_desc *desc;
3251
3252                         desc = func->function.os_desc_table[i].os_desc =
3253                                 vla_ptr(vlabuf, d, os_desc) +
3254                                 i * sizeof(struct usb_os_desc);
3255                         desc->ext_compat_id =
3256                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3257                         INIT_LIST_HEAD(&desc->ext_prop);
3258                 }
3259                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3260                                       vla_ptr(vlabuf, d, raw_descs) +
3261                                       fs_len + hs_len + ss_len,
3262                                       d_raw_descs__sz - fs_len - hs_len -
3263                                       ss_len,
3264                                       __ffs_func_bind_do_os_desc, func);
3265                 if (ret < 0)
3266                         goto error;
3267         }
3268         func->function.os_desc_n =
3269                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3270
3271         /* And we're done */
3272         ffs_event_add(ffs, FUNCTIONFS_BIND);
3273         return 0;
3274
3275 error:
3276         /* XXX Do we need to release all claimed endpoints here? */
3277         return ret;
3278 }
3279
3280 static int ffs_func_bind(struct usb_configuration *c,
3281                          struct usb_function *f)
3282 {
3283         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3284         struct ffs_function *func = ffs_func_from_usb(f);
3285         int ret;
3286
3287         if (IS_ERR(ffs_opts))
3288                 return PTR_ERR(ffs_opts);
3289
3290         ret = _ffs_func_bind(c, f);
3291         if (ret && !--ffs_opts->refcnt)
3292                 functionfs_unbind(func->ffs);
3293
3294         return ret;
3295 }
3296
3297
3298 /* Other USB function hooks *************************************************/
3299
3300 static void ffs_reset_work(struct work_struct *work)
3301 {
3302         struct ffs_data *ffs = container_of(work,
3303                 struct ffs_data, reset_work);
3304         ffs_data_reset(ffs);
3305 }
3306
3307 static int ffs_func_set_alt(struct usb_function *f,
3308                             unsigned interface, unsigned alt)
3309 {
3310         struct ffs_function *func = ffs_func_from_usb(f);
3311         struct ffs_data *ffs = func->ffs;
3312         int ret = 0, intf;
3313
3314         if (alt != (unsigned)-1) {
3315                 intf = ffs_func_revmap_intf(func, interface);
3316                 if (intf < 0)
3317                         return intf;
3318         }
3319
3320         if (ffs->func)
3321                 ffs_func_eps_disable(ffs->func);
3322
3323         if (ffs->state == FFS_DEACTIVATED) {
3324                 ffs->state = FFS_CLOSING;
3325                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3326                 schedule_work(&ffs->reset_work);
3327                 return -ENODEV;
3328         }
3329
3330         if (ffs->state != FFS_ACTIVE)
3331                 return -ENODEV;
3332
3333         if (alt == (unsigned)-1) {
3334                 ffs->func = NULL;
3335                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3336                 return 0;
3337         }
3338
3339         ffs->func = func;
3340         ret = ffs_func_eps_enable(func);
3341         if (ret >= 0)
3342                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3343         return ret;
3344 }
3345
3346 static void ffs_func_disable(struct usb_function *f)
3347 {
3348         ffs_func_set_alt(f, 0, (unsigned)-1);
3349 }
3350
3351 static int ffs_func_setup(struct usb_function *f,
3352                           const struct usb_ctrlrequest *creq)
3353 {
3354         struct ffs_function *func = ffs_func_from_usb(f);
3355         struct ffs_data *ffs = func->ffs;
3356         unsigned long flags;
3357         int ret;
3358
3359         ENTER();
3360
3361         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3362         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3363         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3364         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3365         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3366
3367         /*
3368          * Most requests directed to interface go through here
3369          * (notable exceptions are set/get interface) so we need to
3370          * handle them.  All other either handled by composite or
3371          * passed to usb_configuration->setup() (if one is set).  No
3372          * matter, we will handle requests directed to endpoint here
3373          * as well (as it's straightforward).  Other request recipient
3374          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3375          * is being used.
3376          */
3377         if (ffs->state != FFS_ACTIVE)
3378                 return -ENODEV;
3379
3380         switch (creq->bRequestType & USB_RECIP_MASK) {
3381         case USB_RECIP_INTERFACE:
3382                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3383                 if (ret < 0)
3384                         return ret;
3385                 break;
3386
3387         case USB_RECIP_ENDPOINT:
3388                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3389                 if (ret < 0)
3390                         return ret;
3391                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3392                         ret = func->ffs->eps_addrmap[ret];
3393                 break;
3394
3395         default:
3396                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3397                         ret = le16_to_cpu(creq->wIndex);
3398                 else
3399                         return -EOPNOTSUPP;
3400         }
3401
3402         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3403         ffs->ev.setup = *creq;
3404         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3405         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3406         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3407
3408         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3409 }
3410
3411 static bool ffs_func_req_match(struct usb_function *f,
3412                                const struct usb_ctrlrequest *creq,
3413                                bool config0)
3414 {
3415         struct ffs_function *func = ffs_func_from_usb(f);
3416
3417         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3418                 return false;
3419
3420         switch (creq->bRequestType & USB_RECIP_MASK) {
3421         case USB_RECIP_INTERFACE:
3422                 return (ffs_func_revmap_intf(func,
3423                                              le16_to_cpu(creq->wIndex)) >= 0);
3424         case USB_RECIP_ENDPOINT:
3425                 return (ffs_func_revmap_ep(func,
3426                                            le16_to_cpu(creq->wIndex)) >= 0);
3427         default:
3428                 return (bool) (func->ffs->user_flags &
3429                                FUNCTIONFS_ALL_CTRL_RECIP);
3430         }
3431 }
3432
3433 static void ffs_func_suspend(struct usb_function *f)
3434 {
3435         ENTER();
3436         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3437 }
3438
3439 static void ffs_func_resume(struct usb_function *f)
3440 {
3441         ENTER();
3442         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3443 }
3444
3445
3446 /* Endpoint and interface numbers reverse mapping ***************************/
3447
3448 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3449 {
3450         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3451         return num ? num : -EDOM;
3452 }
3453
3454 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3455 {
3456         short *nums = func->interfaces_nums;
3457         unsigned count = func->ffs->interfaces_count;
3458
3459         for (; count; --count, ++nums) {
3460                 if (*nums >= 0 && *nums == intf)
3461                         return nums - func->interfaces_nums;
3462         }
3463
3464         return -EDOM;
3465 }
3466
3467
3468 /* Devices management *******************************************************/
3469
3470 static LIST_HEAD(ffs_devices);
3471
3472 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3473 {
3474         struct ffs_dev *dev;
3475
3476         if (!name)
3477                 return NULL;
3478
3479         list_for_each_entry(dev, &ffs_devices, entry) {
3480                 if (strcmp(dev->name, name) == 0)
3481                         return dev;
3482         }
3483
3484         return NULL;
3485 }
3486
3487 /*
3488  * ffs_lock must be taken by the caller of this function
3489  */
3490 static struct ffs_dev *_ffs_get_single_dev(void)
3491 {
3492         struct ffs_dev *dev;
3493
3494         if (list_is_singular(&ffs_devices)) {
3495                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3496                 if (dev->single)
3497                         return dev;
3498         }
3499
3500         return NULL;
3501 }
3502
3503 /*
3504  * ffs_lock must be taken by the caller of this function
3505  */
3506 static struct ffs_dev *_ffs_find_dev(const char *name)
3507 {
3508         struct ffs_dev *dev;
3509
3510         dev = _ffs_get_single_dev();
3511         if (dev)
3512                 return dev;
3513
3514         return _ffs_do_find_dev(name);
3515 }
3516
3517 /* Configfs support *********************************************************/
3518
3519 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3520 {
3521         return container_of(to_config_group(item), struct f_fs_opts,
3522                             func_inst.group);
3523 }
3524
3525 static void ffs_attr_release(struct config_item *item)
3526 {
3527         struct f_fs_opts *opts = to_ffs_opts(item);
3528
3529         usb_put_function_instance(&opts->func_inst);
3530 }
3531
3532 static struct configfs_item_operations ffs_item_ops = {
3533         .release        = ffs_attr_release,
3534 };
3535
3536 static const struct config_item_type ffs_func_type = {
3537         .ct_item_ops    = &ffs_item_ops,
3538         .ct_owner       = THIS_MODULE,
3539 };
3540
3541
3542 /* Function registration interface ******************************************/
3543
3544 static void ffs_free_inst(struct usb_function_instance *f)
3545 {
3546         struct f_fs_opts *opts;
3547
3548         opts = to_f_fs_opts(f);
3549         ffs_release_dev(opts->dev);
3550         ffs_dev_lock();
3551         _ffs_free_dev(opts->dev);
3552         ffs_dev_unlock();
3553         kfree(opts);
3554 }
3555
3556 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3557 {
3558         if (strlen(name) >= sizeof_field(struct ffs_dev, name))
3559                 return -ENAMETOOLONG;
3560         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3561 }
3562
3563 static struct usb_function_instance *ffs_alloc_inst(void)
3564 {
3565         struct f_fs_opts *opts;
3566         struct ffs_dev *dev;
3567
3568         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3569         if (!opts)
3570                 return ERR_PTR(-ENOMEM);
3571
3572         opts->func_inst.set_inst_name = ffs_set_inst_name;
3573         opts->func_inst.free_func_inst = ffs_free_inst;
3574         ffs_dev_lock();
3575         dev = _ffs_alloc_dev();
3576         ffs_dev_unlock();
3577         if (IS_ERR(dev)) {
3578                 kfree(opts);
3579                 return ERR_CAST(dev);
3580         }
3581         opts->dev = dev;
3582         dev->opts = opts;
3583
3584         config_group_init_type_name(&opts->func_inst.group, "",
3585                                     &ffs_func_type);
3586         return &opts->func_inst;
3587 }
3588
3589 static void ffs_free(struct usb_function *f)
3590 {
3591         kfree(ffs_func_from_usb(f));
3592 }
3593
3594 static void ffs_func_unbind(struct usb_configuration *c,
3595                             struct usb_function *f)
3596 {
3597         struct ffs_function *func = ffs_func_from_usb(f);
3598         struct ffs_data *ffs = func->ffs;
3599         struct f_fs_opts *opts =
3600                 container_of(f->fi, struct f_fs_opts, func_inst);
3601         struct ffs_ep *ep = func->eps;
3602         unsigned count = ffs->eps_count;
3603         unsigned long flags;
3604
3605         ENTER();
3606         if (ffs->func == func) {
3607                 ffs_func_eps_disable(func);
3608                 ffs->func = NULL;
3609         }
3610
3611         /* Drain any pending AIO completions */
3612         drain_workqueue(ffs->io_completion_wq);
3613
3614         if (!--opts->refcnt)
3615                 functionfs_unbind(ffs);
3616
3617         /* cleanup after autoconfig */
3618         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3619         while (count--) {
3620                 if (ep->ep && ep->req)
3621                         usb_ep_free_request(ep->ep, ep->req);
3622                 ep->req = NULL;
3623                 ++ep;
3624         }
3625         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3626         kfree(func->eps);
3627         func->eps = NULL;
3628         /*
3629          * eps, descriptors and interfaces_nums are allocated in the
3630          * same chunk so only one free is required.
3631          */
3632         func->function.fs_descriptors = NULL;
3633         func->function.hs_descriptors = NULL;
3634         func->function.ss_descriptors = NULL;
3635         func->function.ssp_descriptors = NULL;
3636         func->interfaces_nums = NULL;
3637
3638         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3639 }
3640
3641 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3642 {
3643         struct ffs_function *func;
3644
3645         ENTER();
3646
3647         func = kzalloc(sizeof(*func), GFP_KERNEL);
3648         if (!func)
3649                 return ERR_PTR(-ENOMEM);
3650
3651         func->function.name    = "Function FS Gadget";
3652
3653         func->function.bind    = ffs_func_bind;
3654         func->function.unbind  = ffs_func_unbind;
3655         func->function.set_alt = ffs_func_set_alt;
3656         func->function.disable = ffs_func_disable;
3657         func->function.setup   = ffs_func_setup;
3658         func->function.req_match = ffs_func_req_match;
3659         func->function.suspend = ffs_func_suspend;
3660         func->function.resume  = ffs_func_resume;
3661         func->function.free_func = ffs_free;
3662
3663         return &func->function;
3664 }
3665
3666 /*
3667  * ffs_lock must be taken by the caller of this function
3668  */
3669 static struct ffs_dev *_ffs_alloc_dev(void)
3670 {
3671         struct ffs_dev *dev;
3672         int ret;
3673
3674         if (_ffs_get_single_dev())
3675                         return ERR_PTR(-EBUSY);
3676
3677         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3678         if (!dev)
3679                 return ERR_PTR(-ENOMEM);
3680
3681         if (list_empty(&ffs_devices)) {
3682                 ret = functionfs_init();
3683                 if (ret) {
3684                         kfree(dev);
3685                         return ERR_PTR(ret);
3686                 }
3687         }
3688
3689         list_add(&dev->entry, &ffs_devices);
3690
3691         return dev;
3692 }
3693
3694 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3695 {
3696         struct ffs_dev *existing;
3697         int ret = 0;
3698
3699         ffs_dev_lock();
3700
3701         existing = _ffs_do_find_dev(name);
3702         if (!existing)
3703                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3704         else if (existing != dev)
3705                 ret = -EBUSY;
3706
3707         ffs_dev_unlock();
3708
3709         return ret;
3710 }
3711 EXPORT_SYMBOL_GPL(ffs_name_dev);
3712
3713 int ffs_single_dev(struct ffs_dev *dev)
3714 {
3715         int ret;
3716
3717         ret = 0;
3718         ffs_dev_lock();
3719
3720         if (!list_is_singular(&ffs_devices))
3721                 ret = -EBUSY;
3722         else
3723                 dev->single = true;
3724
3725         ffs_dev_unlock();
3726         return ret;
3727 }
3728 EXPORT_SYMBOL_GPL(ffs_single_dev);
3729
3730 /*
3731  * ffs_lock must be taken by the caller of this function
3732  */
3733 static void _ffs_free_dev(struct ffs_dev *dev)
3734 {
3735         list_del(&dev->entry);
3736
3737         kfree(dev);
3738         if (list_empty(&ffs_devices))
3739                 functionfs_cleanup();
3740 }
3741
3742 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data)
3743 {
3744         int ret = 0;
3745         struct ffs_dev *ffs_dev;
3746
3747         ENTER();
3748         ffs_dev_lock();
3749
3750         ffs_dev = _ffs_find_dev(dev_name);
3751         if (!ffs_dev) {
3752                 ret = -ENOENT;
3753         } else if (ffs_dev->mounted) {
3754                 ret = -EBUSY;
3755         } else if (ffs_dev->ffs_acquire_dev_callback &&
3756                    ffs_dev->ffs_acquire_dev_callback(ffs_dev)) {
3757                 ret = -ENOENT;
3758         } else {
3759                 ffs_dev->mounted = true;
3760                 ffs_dev->ffs_data = ffs_data;
3761                 ffs_data->private_data = ffs_dev;
3762         }
3763
3764         ffs_dev_unlock();
3765         return ret;
3766 }
3767
3768 static void ffs_release_dev(struct ffs_dev *ffs_dev)
3769 {
3770         ENTER();
3771         ffs_dev_lock();
3772
3773         if (ffs_dev && ffs_dev->mounted) {
3774                 ffs_dev->mounted = false;
3775                 if (ffs_dev->ffs_data) {
3776                         ffs_dev->ffs_data->private_data = NULL;
3777                         ffs_dev->ffs_data = NULL;
3778                 }
3779
3780                 if (ffs_dev->ffs_release_dev_callback)
3781                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3782         }
3783
3784         ffs_dev_unlock();
3785 }
3786
3787 static int ffs_ready(struct ffs_data *ffs)
3788 {
3789         struct ffs_dev *ffs_obj;
3790         int ret = 0;
3791
3792         ENTER();
3793         ffs_dev_lock();
3794
3795         ffs_obj = ffs->private_data;
3796         if (!ffs_obj) {
3797                 ret = -EINVAL;
3798                 goto done;
3799         }
3800         if (WARN_ON(ffs_obj->desc_ready)) {
3801                 ret = -EBUSY;
3802                 goto done;
3803         }
3804
3805         ffs_obj->desc_ready = true;
3806
3807         if (ffs_obj->ffs_ready_callback) {
3808                 ret = ffs_obj->ffs_ready_callback(ffs);
3809                 if (ret)
3810                         goto done;
3811         }
3812
3813         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3814 done:
3815         ffs_dev_unlock();
3816         return ret;
3817 }
3818
3819 static void ffs_closed(struct ffs_data *ffs)
3820 {
3821         struct ffs_dev *ffs_obj;
3822         struct f_fs_opts *opts;
3823         struct config_item *ci;
3824
3825         ENTER();
3826         ffs_dev_lock();
3827
3828         ffs_obj = ffs->private_data;
3829         if (!ffs_obj)
3830                 goto done;
3831
3832         ffs_obj->desc_ready = false;
3833
3834         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3835             ffs_obj->ffs_closed_callback)
3836                 ffs_obj->ffs_closed_callback(ffs);
3837
3838         if (ffs_obj->opts)
3839                 opts = ffs_obj->opts;
3840         else
3841                 goto done;
3842
3843         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3844             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3845                 goto done;
3846
3847         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3848         ffs_dev_unlock();
3849
3850         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3851                 unregister_gadget_item(ci);
3852         return;
3853 done:
3854         ffs_dev_unlock();
3855 }
3856
3857 /* Misc helper functions ****************************************************/
3858
3859 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3860 {
3861         return nonblock
3862                 ? mutex_trylock(mutex) ? 0 : -EAGAIN
3863                 : mutex_lock_interruptible(mutex);
3864 }
3865
3866 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3867 {
3868         char *data;
3869
3870         if (!len)
3871                 return NULL;
3872
3873         data = memdup_user(buf, len);
3874         if (IS_ERR(data))
3875                 return data;
3876
3877         pr_vdebug("Buffer from user space:\n");
3878         ffs_dump_mem("", data, len);
3879
3880         return data;
3881 }
3882
3883 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3884 MODULE_LICENSE("GPL");
3885 MODULE_AUTHOR("Michal Nazarewicz");