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/mmu_context.h>
  36 #include <linux/poll.h>
  37 #include <linux/eventfd.h>
  38
  39 #include "u_fs.h"
  40 #include "u_f.h"
  41 #include "u_os_desc.h"
  42 #include "configfs.h"
  43
  44 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  45
  46 /* Reference counter handling */
  47 static void ffs_data_get(struct ffs_data *ffs);
  48 static void ffs_data_put(struct ffs_data *ffs);
  49 /* Creates new ffs_data object. */
  50 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  51         __attribute__((malloc));
  52
  53 /* Opened counter handling. */
  54 static void ffs_data_opened(struct ffs_data *ffs);
  55 static void ffs_data_closed(struct ffs_data *ffs);
  56
  57 /* Called with ffs->mutex held; take over ownership of data. */
  58 static int __must_check
  59 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  60 static int __must_check
  61 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  62
  63
  64 /* The function structure ***************************************************/
  65
  66 struct ffs_ep;
  67
  68 struct ffs_function {
  69         struct usb_configuration        *conf;
  70         struct usb_gadget               *gadget;
  71         struct ffs_data                 *ffs;
  72
  73         struct ffs_ep                   *eps;
  74         u8                              eps_revmap[16];
  75         short                           *interfaces_nums;
  76
  77         struct usb_function             function;
  78 };
  79
  80
  81 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  82 {
  83         return container_of(f, struct ffs_function, function);
  84 }
  85
  86
  87 static inline enum ffs_setup_state
  88 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  89 {
  90         return (enum ffs_setup_state)
  91                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  92 }
  93
  94
  95 static void ffs_func_eps_disable(struct ffs_function *func);
  96 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  97
  98 static int ffs_func_bind(struct usb_configuration *,
  99                          struct usb_function *);
 100 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 101 static void ffs_func_disable(struct usb_function *);
 102 static int ffs_func_setup(struct usb_function *,
 103                           const struct usb_ctrlrequest *);
 104 static bool ffs_func_req_match(struct usb_function *,
 105                                const struct usb_ctrlrequest *,
 106                                bool config0);
 107 static void ffs_func_suspend(struct usb_function *);
 108 static void ffs_func_resume(struct usb_function *);
 109
 110
 111 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 112 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 113
 114
 115 /* The endpoints structures *************************************************/
 116
 117 struct ffs_ep {
 118         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 119         struct usb_request              *req;   /* P: epfile->mutex */
 120
 121         /* [0]: full speed, [1]: high speed, [2]: super speed */
 122         struct usb_endpoint_descriptor  *descs[3];
 123
 124         u8                              num;
 125
 126         int                             status; /* P: epfile->mutex */
 127 };
 128
 129 struct ffs_epfile {
 130         /* Protects ep->ep and ep->req. */
 131         struct mutex                    mutex;
 132
 133         struct ffs_data                 *ffs;
 134         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 135
 136         struct dentry                   *dentry;
 137
 138         /*
 139          * Buffer for holding data from partial reads which may happen since
 140          * we’re rounding user read requests to a multiple of a max packet size.
 141          *
 142          * The pointer is initialised with NULL value and may be set by
 143          * __ffs_epfile_read_data function to point to a temporary buffer.
 144          *
 145          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 146          * data from said buffer and eventually free it.  Importantly, while the
 147          * function is using the buffer, it sets the pointer to NULL.  This is
 148          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 149          * can never run concurrently (they are synchronised by epfile->mutex)
 150          * so the latter will not assign a new value to the pointer.
 151          *
 152          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 153          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 154          * value is crux of the synchronisation between ffs_func_eps_disable and
 155          * __ffs_epfile_read_data.
 156          *
 157          * Once __ffs_epfile_read_data is about to finish it will try to set the
 158          * pointer back to its old value (as described above), but seeing as the
 159          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 160          * the buffer.
 161          *
 162          * == State transitions ==
 163          *
 164          * • ptr == NULL:  (initial state)
 165          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 166          *   ◦ __ffs_epfile_read_buffered:    nop
 167          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 168          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 169          * • ptr == DROP:
 170          *   ◦ __ffs_epfile_read_buffer_free: nop
 171          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 172          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 173          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 174          * • ptr == buf:
 175          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 176          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 177          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 178          *                                    is always called first
 179          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 180          * • ptr == NULL and reading:
 181          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 182          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 183          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 184          *   ◦ reading finishes and …
 185          *     … all data read:               free buf, go to ptr == NULL
 186          *     … otherwise:                   go to ptr == buf and reading
 187          * • ptr == DROP and reading:
 188          *   ◦ __ffs_epfile_read_buffer_free: nop
 189          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 190          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 191          *   ◦ reading finishes:              free buf, go to ptr == DROP
 192          */
 193         struct ffs_buffer               *read_buffer;
 194 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 195
 196         char                            name[5];
 197
 198         unsigned char                   in;     /* P: ffs->eps_lock */
 199         unsigned char                   isoc;   /* P: ffs->eps_lock */
 200
 201         unsigned char                   _pad;
 202 };
 203
 204 struct ffs_buffer {
 205         size_t length;
 206         char *data;
 207         char storage[];
 208 };
 209
 210 /*  ffs_io_data structure ***************************************************/
 211
 212 struct ffs_io_data {
 213         bool aio;
 214         bool read;
 215
 216         struct kiocb *kiocb;
 217         struct iov_iter data;
 218         const void *to_free;
 219         char *buf;
 220
 221         struct mm_struct *mm;
 222         struct work_struct work;
 223
 224         struct usb_ep *ep;
 225         struct usb_request *req;
 226         struct sg_table sgt;
 227         bool use_sg;
 228
 229         struct ffs_data *ffs;
 230 };
 231
 232 struct ffs_desc_helper {
 233         struct ffs_data *ffs;
 234         unsigned interfaces_count;
 235         unsigned eps_count;
 236 };
 237
 238 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 239 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 240
 241 static struct dentry *
 242 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 243                    const struct file_operations *fops);
 244
 245 /* Devices management *******************************************************/
 246
 247 DEFINE_MUTEX(ffs_lock);
 248 EXPORT_SYMBOL_GPL(ffs_lock);
 249
 250 static struct ffs_dev *_ffs_find_dev(const char *name);
 251 static struct ffs_dev *_ffs_alloc_dev(void);
 252 static void _ffs_free_dev(struct ffs_dev *dev);
 253 static void *ffs_acquire_dev(const char *dev_name);
 254 static void ffs_release_dev(struct ffs_data *ffs_data);
 255 static int ffs_ready(struct ffs_data *ffs);
 256 static void ffs_closed(struct ffs_data *ffs);
 257
 258 /* Misc helper functions ****************************************************/
 259
 260 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 261         __attribute__((warn_unused_result, nonnull));
 262 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 263         __attribute__((warn_unused_result, nonnull));
 264
 265
 266 /* Control file aka ep0 *****************************************************/
 267
 268 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 269 {
 270         struct ffs_data *ffs = req->context;
 271
 272         complete(&ffs->ep0req_completion);
 273 }
 274
 275 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 276         __releases(&ffs->ev.waitq.lock)
 277 {
 278         struct usb_request *req = ffs->ep0req;
 279         int ret;
 280
 281         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 282
 283         spin_unlock_irq(&ffs->ev.waitq.lock);
 284
 285         req->buf      = data;
 286         req->length   = len;
 287
 288         /*
 289          * UDC layer requires to provide a buffer even for ZLP, but should
 290          * not use it at all. Let's provide some poisoned pointer to catch
 291          * possible bug in the driver.
 292          */
 293         if (req->buf == NULL)
 294                 req->buf = (void *)0xDEADBABE;
 295
 296         reinit_completion(&ffs->ep0req_completion);
 297
 298         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 299         if (unlikely(ret < 0))
 300                 return ret;
 301
 302         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 303         if (unlikely(ret)) {
 304                 usb_ep_dequeue(ffs->gadget->ep0, req);
 305                 return -EINTR;
 306         }
 307
 308         ffs->setup_state = FFS_NO_SETUP;
 309         return req->status ? req->status : req->actual;
 310 }
 311
 312 static int __ffs_ep0_stall(struct ffs_data *ffs)
 313 {
 314         if (ffs->ev.can_stall) {
 315                 pr_vdebug("ep0 stall\n");
 316                 usb_ep_set_halt(ffs->gadget->ep0);
 317                 ffs->setup_state = FFS_NO_SETUP;
 318                 return -EL2HLT;
 319         } else {
 320                 pr_debug("bogus ep0 stall!\n");
 321                 return -ESRCH;
 322         }
 323 }
 324
 325 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 326                              size_t len, loff_t *ptr)
 327 {
 328         struct ffs_data *ffs = file->private_data;
 329         ssize_t ret;
 330         char *data;
 331
 332         ENTER();
 333
 334         /* Fast check if setup was canceled */
 335         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 336                 return -EIDRM;
 337
 338         /* Acquire mutex */
 339         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 340         if (unlikely(ret < 0))
 341                 return ret;
 342
 343         /* Check state */
 344         switch (ffs->state) {
 345         case FFS_READ_DESCRIPTORS:
 346         case FFS_READ_STRINGS:
 347                 /* Copy data */
 348                 if (unlikely(len < 16)) {
 349                         ret = -EINVAL;
 350                         break;
 351                 }
 352
 353                 data = ffs_prepare_buffer(buf, len);
 354                 if (IS_ERR(data)) {
 355                         ret = PTR_ERR(data);
 356                         break;
 357                 }
 358
 359                 /* Handle data */
 360                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 361                         pr_info("read descriptors\n");
 362                         ret = __ffs_data_got_descs(ffs, data, len);
 363                         if (unlikely(ret < 0))
 364                                 break;
 365
 366                         ffs->state = FFS_READ_STRINGS;
 367                         ret = len;
 368                 } else {
 369                         pr_info("read strings\n");
 370                         ret = __ffs_data_got_strings(ffs, data, len);
 371                         if (unlikely(ret < 0))
 372                                 break;
 373
 374                         ret = ffs_epfiles_create(ffs);
 375                         if (unlikely(ret)) {
 376                                 ffs->state = FFS_CLOSING;
 377                                 break;
 378                         }
 379
 380                         ffs->state = FFS_ACTIVE;
 381                         mutex_unlock(&ffs->mutex);
 382
 383                         ret = ffs_ready(ffs);
 384                         if (unlikely(ret < 0)) {
 385                                 ffs->state = FFS_CLOSING;
 386                                 return ret;
 387                         }
 388
 389                         return len;
 390                 }
 391                 break;
 392
 393         case FFS_ACTIVE:
 394                 data = NULL;
 395                 /*
 396                  * We're called from user space, we can use _irq
 397                  * rather then _irqsave
 398                  */
 399                 spin_lock_irq(&ffs->ev.waitq.lock);
 400                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 401                 case FFS_SETUP_CANCELLED:
 402                         ret = -EIDRM;
 403                         goto done_spin;
 404
 405                 case FFS_NO_SETUP:
 406                         ret = -ESRCH;
 407                         goto done_spin;
 408
 409                 case FFS_SETUP_PENDING:
 410                         break;
 411                 }
 412
 413                 /* FFS_SETUP_PENDING */
 414                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 415                         spin_unlock_irq(&ffs->ev.waitq.lock);
 416                         ret = __ffs_ep0_stall(ffs);
 417                         break;
 418                 }
 419
 420                 /* FFS_SETUP_PENDING and not stall */
 421                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 422
 423                 spin_unlock_irq(&ffs->ev.waitq.lock);
 424
 425                 data = ffs_prepare_buffer(buf, len);
 426                 if (IS_ERR(data)) {
 427                         ret = PTR_ERR(data);
 428                         break;
 429                 }
 430
 431                 spin_lock_irq(&ffs->ev.waitq.lock);
 432
 433                 /*
 434                  * We are guaranteed to be still in FFS_ACTIVE state
 435                  * but the state of setup could have changed from
 436                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 437                  * to check for that.  If that happened we copied data
 438                  * from user space in vain but it's unlikely.
 439                  *
 440                  * For sure we are not in FFS_NO_SETUP since this is
 441                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 442                  * transition can be performed and it's protected by
 443                  * mutex.
 444                  */
 445                 if (ffs_setup_state_clear_cancelled(ffs) ==
 446                     FFS_SETUP_CANCELLED) {
 447                         ret = -EIDRM;
 448 done_spin:
 449                         spin_unlock_irq(&ffs->ev.waitq.lock);
 450                 } else {
 451                         /* unlocks spinlock */
 452                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 453                 }
 454                 kfree(data);
 455                 break;
 456
 457         default:
 458                 ret = -EBADFD;
 459                 break;
 460         }
 461
 462         mutex_unlock(&ffs->mutex);
 463         return ret;
 464 }
 465
 466 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 467 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 468                                      size_t n)
 469         __releases(&ffs->ev.waitq.lock)
 470 {
 471         /*
 472          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 473          * size of ffs->ev.types array (which is four) so that's how much space
 474          * we reserve.
 475          */
 476         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 477         const size_t size = n * sizeof *events;
 478         unsigned i = 0;
 479
 480         memset(events, 0, size);
 481
 482         do {
 483                 events[i].type = ffs->ev.types[i];
 484                 if (events[i].type == FUNCTIONFS_SETUP) {
 485                         events[i].u.setup = ffs->ev.setup;
 486                         ffs->setup_state = FFS_SETUP_PENDING;
 487                 }
 488         } while (++i < n);
 489
 490         ffs->ev.count -= n;
 491         if (ffs->ev.count)
 492                 memmove(ffs->ev.types, ffs->ev.types + n,
 493                         ffs->ev.count * sizeof *ffs->ev.types);
 494
 495         spin_unlock_irq(&ffs->ev.waitq.lock);
 496         mutex_unlock(&ffs->mutex);
 497
 498         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 499 }
 500
 501 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 502                             size_t len, loff_t *ptr)
 503 {
 504         struct ffs_data *ffs = file->private_data;
 505         char *data = NULL;
 506         size_t n;
 507         int ret;
 508
 509         ENTER();
 510
 511         /* Fast check if setup was canceled */
 512         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 513                 return -EIDRM;
 514
 515         /* Acquire mutex */
 516         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 517         if (unlikely(ret < 0))
 518                 return ret;
 519
 520         /* Check state */
 521         if (ffs->state != FFS_ACTIVE) {
 522                 ret = -EBADFD;
 523                 goto done_mutex;
 524         }
 525
 526         /*
 527          * We're called from user space, we can use _irq rather then
 528          * _irqsave
 529          */
 530         spin_lock_irq(&ffs->ev.waitq.lock);
 531
 532         switch (ffs_setup_state_clear_cancelled(ffs)) {
 533         case FFS_SETUP_CANCELLED:
 534                 ret = -EIDRM;
 535                 break;
 536
 537         case FFS_NO_SETUP:
 538                 n = len / sizeof(struct usb_functionfs_event);
 539                 if (unlikely(!n)) {
 540                         ret = -EINVAL;
 541                         break;
 542                 }
 543
 544                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 545                         ret = -EAGAIN;
 546                         break;
 547                 }
 548
 549                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 550                                                         ffs->ev.count)) {
 551                         ret = -EINTR;
 552                         break;
 553                 }
 554
 555                 /* unlocks spinlock */
 556                 return __ffs_ep0_read_events(ffs, buf,
 557                                              min(n, (size_t)ffs->ev.count));
 558
 559         case FFS_SETUP_PENDING:
 560                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 561                         spin_unlock_irq(&ffs->ev.waitq.lock);
 562                         ret = __ffs_ep0_stall(ffs);
 563                         goto done_mutex;
 564                 }
 565
 566                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 567
 568                 spin_unlock_irq(&ffs->ev.waitq.lock);
 569
 570                 if (likely(len)) {
 571                         data = kmalloc(len, GFP_KERNEL);
 572                         if (unlikely(!data)) {
 573                                 ret = -ENOMEM;
 574                                 goto done_mutex;
 575                         }
 576                 }
 577
 578                 spin_lock_irq(&ffs->ev.waitq.lock);
 579
 580                 /* See ffs_ep0_write() */
 581                 if (ffs_setup_state_clear_cancelled(ffs) ==
 582                     FFS_SETUP_CANCELLED) {
 583                         ret = -EIDRM;
 584                         break;
 585                 }
 586
 587                 /* unlocks spinlock */
 588                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 589                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 590                         ret = -EFAULT;
 591                 goto done_mutex;
 592
 593         default:
 594                 ret = -EBADFD;
 595                 break;
 596         }
 597
 598         spin_unlock_irq(&ffs->ev.waitq.lock);
 599 done_mutex:
 600         mutex_unlock(&ffs->mutex);
 601         kfree(data);
 602         return ret;
 603 }
 604
 605 static int ffs_ep0_open(struct inode *inode, struct file *file)
 606 {
 607         struct ffs_data *ffs = inode->i_private;
 608
 609         ENTER();
 610
 611         if (unlikely(ffs->state == FFS_CLOSING))
 612                 return -EBUSY;
 613
 614         file->private_data = ffs;
 615         ffs_data_opened(ffs);
 616
 617         return 0;
 618 }
 619
 620 static int ffs_ep0_release(struct inode *inode, struct file *file)
 621 {
 622         struct ffs_data *ffs = file->private_data;
 623
 624         ENTER();
 625
 626         ffs_data_closed(ffs);
 627
 628         return 0;
 629 }
 630
 631 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 632 {
 633         struct ffs_data *ffs = file->private_data;
 634         struct usb_gadget *gadget = ffs->gadget;
 635         long ret;
 636
 637         ENTER();
 638
 639         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 640                 struct ffs_function *func = ffs->func;
 641                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 642         } else if (gadget && gadget->ops->ioctl) {
 643                 ret = gadget->ops->ioctl(gadget, code, value);
 644         } else {
 645                 ret = -ENOTTY;
 646         }
 647
 648         return ret;
 649 }
 650
 651 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 652 {
 653         struct ffs_data *ffs = file->private_data;
 654         __poll_t mask = EPOLLWRNORM;
 655         int ret;
 656
 657         poll_wait(file, &ffs->ev.waitq, wait);
 658
 659         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 660         if (unlikely(ret < 0))
 661                 return mask;
 662
 663         switch (ffs->state) {
 664         case FFS_READ_DESCRIPTORS:
 665         case FFS_READ_STRINGS:
 666                 mask |= EPOLLOUT;
 667                 break;
 668
 669         case FFS_ACTIVE:
 670                 switch (ffs->setup_state) {
 671                 case FFS_NO_SETUP:
 672                         if (ffs->ev.count)
 673                                 mask |= EPOLLIN;
 674                         break;
 675
 676                 case FFS_SETUP_PENDING:
 677                 case FFS_SETUP_CANCELLED:
 678                         mask |= (EPOLLIN | EPOLLOUT);
 679                         break;
 680                 }
 681         case FFS_CLOSING:
 682                 break;
 683         case FFS_DEACTIVATED:
 684                 break;
 685         }
 686
 687         mutex_unlock(&ffs->mutex);
 688
 689         return mask;
 690 }
 691
 692 static const struct file_operations ffs_ep0_operations = {
 693         .llseek =       no_llseek,
 694
 695         .open =         ffs_ep0_open,
 696         .write =        ffs_ep0_write,
 697         .read =         ffs_ep0_read,
 698         .release =      ffs_ep0_release,
 699         .unlocked_ioctl =       ffs_ep0_ioctl,
 700         .poll =         ffs_ep0_poll,
 701 };
 702
 703
 704 /* "Normal" endpoints operations ********************************************/
 705
 706 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 707 {
 708         ENTER();
 709         if (likely(req->context)) {
 710                 struct ffs_ep *ep = _ep->driver_data;
 711                 ep->status = req->status ? req->status : req->actual;
 712                 complete(req->context);
 713         }
 714 }
 715
 716 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 717 {
 718         ssize_t ret = copy_to_iter(data, data_len, iter);
 719         if (likely(ret == data_len))
 720                 return ret;
 721
 722         if (unlikely(iov_iter_count(iter)))
 723                 return -EFAULT;
 724
 725         /*
 726          * Dear user space developer!
 727          *
 728          * TL;DR: To stop getting below error message in your kernel log, change
 729          * user space code using functionfs to align read buffers to a max
 730          * packet size.
 731          *
 732          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 733          * packet size.  When unaligned buffer is passed to functionfs, it
 734          * internally uses a larger, aligned buffer so that such UDCs are happy.
 735          *
 736          * Unfortunately, this means that host may send more data than was
 737          * requested in read(2) system call.  f_fs doesn’t know what to do with
 738          * that excess data so it simply drops it.
 739          *
 740          * Was the buffer aligned in the first place, no such problem would
 741          * happen.
 742          *
 743          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 744          * by splitting a request into multiple parts.  This splitting may still
 745          * be a problem though so it’s likely best to align the buffer
 746          * regardless of it being AIO or not..
 747          *
 748          * This only affects OUT endpoints, i.e. reading data with a read(2),
 749          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 750          * affected.
 751          */
 752         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 753                "Align read buffer size to max packet size to avoid the problem.\n",
 754                data_len, ret);
 755
 756         return ret;
 757 }
 758
 759 /*
 760  * allocate a virtually contiguous buffer and create a scatterlist describing it
 761  * @sg_table    - pointer to a place to be filled with sg_table contents
 762  * @size        - required buffer size
 763  */
 764 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 765 {
 766         struct page **pages;
 767         void *vaddr, *ptr;
 768         unsigned int n_pages;
 769         int i;
 770
 771         vaddr = vmalloc(sz);
 772         if (!vaddr)
 773                 return NULL;
 774
 775         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 776         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 777         if (!pages) {
 778                 vfree(vaddr);
 779
 780                 return NULL;
 781         }
 782         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 783                 pages[i] = vmalloc_to_page(ptr);
 784
 785         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 786                 kvfree(pages);
 787                 vfree(vaddr);
 788
 789                 return NULL;
 790         }
 791         kvfree(pages);
 792
 793         return vaddr;
 794 }
 795
 796 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 797         size_t data_len)
 798 {
 799         if (io_data->use_sg)
 800                 return ffs_build_sg_list(&io_data->sgt, data_len);
 801
 802         return kmalloc(data_len, GFP_KERNEL);
 803 }
 804
 805 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 806 {
 807         if (!io_data->buf)
 808                 return;
 809
 810         if (io_data->use_sg) {
 811                 sg_free_table(&io_data->sgt);
 812                 vfree(io_data->buf);
 813         } else {
 814                 kfree(io_data->buf);
 815         }
 816 }
 817
 818 static void ffs_user_copy_worker(struct work_struct *work)
 819 {
 820         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 821                                                    work);
 822         int ret = io_data->req->status ? io_data->req->status :
 823                                          io_data->req->actual;
 824         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 825
 826         if (io_data->read && ret > 0) {
 827                 mm_segment_t oldfs = get_fs();
 828
 829                 set_fs(USER_DS);
 830                 use_mm(io_data->mm);
 831                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 832                 unuse_mm(io_data->mm);
 833                 set_fs(oldfs);
 834         }
 835
 836         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 837
 838         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 839                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 840
 841         usb_ep_free_request(io_data->ep, io_data->req);
 842
 843         if (io_data->read)
 844                 kfree(io_data->to_free);
 845         ffs_free_buffer(io_data);
 846         kfree(io_data);
 847 }
 848
 849 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 850                                          struct usb_request *req)
 851 {
 852         struct ffs_io_data *io_data = req->context;
 853         struct ffs_data *ffs = io_data->ffs;
 854
 855         ENTER();
 856
 857         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 858         queue_work(ffs->io_completion_wq, &io_data->work);
 859 }
 860
 861 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 862 {
 863         /*
 864          * See comment in struct ffs_epfile for full read_buffer pointer
 865          * synchronisation story.
 866          */
 867         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 868         if (buf && buf != READ_BUFFER_DROP)
 869                 kfree(buf);
 870 }
 871
 872 /* Assumes epfile->mutex is held. */
 873 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 874                                           struct iov_iter *iter)
 875 {
 876         /*
 877          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 878          * the buffer while we are using it.  See comment in struct ffs_epfile
 879          * for full read_buffer pointer synchronisation story.
 880          */
 881         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 882         ssize_t ret;
 883         if (!buf || buf == READ_BUFFER_DROP)
 884                 return 0;
 885
 886         ret = copy_to_iter(buf->data, buf->length, iter);
 887         if (buf->length == ret) {
 888                 kfree(buf);
 889                 return ret;
 890         }
 891
 892         if (unlikely(iov_iter_count(iter))) {
 893                 ret = -EFAULT;
 894         } else {
 895                 buf->length -= ret;
 896                 buf->data += ret;
 897         }
 898
 899         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 900                 kfree(buf);
 901
 902         return ret;
 903 }
 904
 905 /* Assumes epfile->mutex is held. */
 906 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 907                                       void *data, int data_len,
 908                                       struct iov_iter *iter)
 909 {
 910         struct ffs_buffer *buf;
 911
 912         ssize_t ret = copy_to_iter(data, data_len, iter);
 913         if (likely(data_len == ret))
 914                 return ret;
 915
 916         if (unlikely(iov_iter_count(iter)))
 917                 return -EFAULT;
 918
 919         /* See ffs_copy_to_iter for more context. */
 920         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 921                 data_len, ret);
 922
 923         data_len -= ret;
 924         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 925         if (!buf)
 926                 return -ENOMEM;
 927         buf->length = data_len;
 928         buf->data = buf->storage;
 929         memcpy(buf->storage, data + ret, data_len);
 930
 931         /*
 932          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 933          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 934          * in struct ffs_epfile for full read_buffer pointer synchronisation
 935          * story.
 936          */
 937         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 938                 kfree(buf);
 939
 940         return ret;
 941 }
 942
 943 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 944 {
 945         struct ffs_epfile *epfile = file->private_data;
 946         struct usb_request *req;
 947         struct ffs_ep *ep;
 948         char *data = NULL;
 949         ssize_t ret, data_len = -EINVAL;
 950         int halt;
 951
 952         /* Are we still active? */
 953         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 954                 return -ENODEV;
 955
 956         /* Wait for endpoint to be enabled */
 957         ep = epfile->ep;
 958         if (!ep) {
 959                 if (file->f_flags & O_NONBLOCK)
 960                         return -EAGAIN;
 961
 962                 ret = wait_event_interruptible(
 963                                 epfile->ffs->wait, (ep = epfile->ep));
 964                 if (ret)
 965                         return -EINTR;
 966         }
 967
 968         /* Do we halt? */
 969         halt = (!io_data->read == !epfile->in);
 970         if (halt && epfile->isoc)
 971                 return -EINVAL;
 972
 973         /* We will be using request and read_buffer */
 974         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 975         if (unlikely(ret))
 976                 goto error;
 977
 978         /* Allocate & copy */
 979         if (!halt) {
 980                 struct usb_gadget *gadget;
 981
 982                 /*
 983                  * Do we have buffered data from previous partial read?  Check
 984                  * that for synchronous case only because we do not have
 985                  * facility to ‘wake up’ a pending asynchronous read and push
 986                  * buffered data to it which we would need to make things behave
 987                  * consistently.
 988                  */
 989                 if (!io_data->aio && io_data->read) {
 990                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 991                         if (ret)
 992                                 goto error_mutex;
 993                 }
 994
 995                 /*
 996                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 997                  * before the waiting completes, so do not assign to 'gadget'
 998                  * earlier
 999                  */
1000                 gadget = epfile->ffs->gadget;
1001
1002                 spin_lock_irq(&epfile->ffs->eps_lock);
1003                 /* In the meantime, endpoint got disabled or changed. */
1004                 if (epfile->ep != ep) {
1005                         ret = -ESHUTDOWN;
1006                         goto error_lock;
1007                 }
1008                 data_len = iov_iter_count(&io_data->data);
1009                 /*
1010                  * Controller may require buffer size to be aligned to
1011                  * maxpacketsize of an out endpoint.
1012                  */
1013                 if (io_data->read)
1014                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1015
1016                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1017                 spin_unlock_irq(&epfile->ffs->eps_lock);
1018
1019 retry_malloc:
1020                 data = kmalloc(data_len, GFP_KERNEL | __GFP_NOWARN);
1021                 if (unlikely(!data)) {
1022                         /*
1023                          * f_fs daemons usually use large size buffer for
1024                          * performance. However, this can cause failure of
1025                          * kmalloc() due to buddy fragmentation, even if there
1026                          * is available memory and thus it can be compacted by
1027                          * by kswapd. Therefore, instead of just returning error
1028                          * to daemon in the case of failure of kmalloc(), give
1029                          * the second chance to allocate buffer with a half size
1030                          * until it really fails due to memory shortage.
1031                          */
1032                         if (unlikely(data_len <= PAGE_SIZE)) {
1033                                 ret = -ENOMEM;
1034                                 goto error_mutex;
1035                         }
1036
1037                         data_len = data_len >> 1;
1038
1039                         if (io_data->read) {
1040                                 spin_lock_irq(&epfile->ffs->eps_lock);
1041                                 data_len = usb_ep_align_maybe(gadget,
1042                                                 ep->ep, data_len);
1043                                 spin_unlock_irq(&epfile->ffs->eps_lock);
1044                         }
1045
1046                         goto retry_malloc;
1047                 }
1048                 if (!io_data->read &&
1049                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1050                         ret = -EFAULT;
1051                         goto error_mutex;
1052                 }
1053         }
1054
1055         spin_lock_irq(&epfile->ffs->eps_lock);
1056
1057         if (epfile->ep != ep) {
1058                 /* In the meantime, endpoint got disabled or changed. */
1059                 ret = -ESHUTDOWN;
1060         } else if (halt) {
1061                 ret = usb_ep_set_halt(ep->ep);
1062                 if (!ret)
1063                         ret = -EBADMSG;
1064         } else if (unlikely(data_len == -EINVAL)) {
1065                 /*
1066                  * Sanity Check: even though data_len can't be used
1067                  * uninitialized at the time I write this comment, some
1068                  * compilers complain about this situation.
1069                  * In order to keep the code clean from warnings, data_len is
1070                  * being initialized to -EINVAL during its declaration, which
1071                  * means we can't rely on compiler anymore to warn no future
1072                  * changes won't result in data_len being used uninitialized.
1073                  * For such reason, we're adding this redundant sanity check
1074                  * here.
1075                  */
1076                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1077                 ret = -EINVAL;
1078         } else if (!io_data->aio) {
1079                 DECLARE_COMPLETION_ONSTACK(done);
1080                 bool interrupted = false;
1081
1082                 req = ep->req;
1083                 if (io_data->use_sg) {
1084                         req->buf = NULL;
1085                         req->sg = io_data->sgt.sgl;
1086                         req->num_sgs = io_data->sgt.nents;
1087                 } else {
1088                         req->buf = data;
1089                         req->num_sgs = 0;
1090                 }
1091                 req->length = data_len;
1092
1093                 io_data->buf = data;
1094
1095                 req->context  = &done;
1096                 req->complete = ffs_epfile_io_complete;
1097
1098                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1099                 if (unlikely(ret < 0))
1100                         goto error_lock;
1101
1102                 spin_unlock_irq(&epfile->ffs->eps_lock);
1103
1104                 if (unlikely(wait_for_completion_interruptible(&done)) &&
1105                     epfile->ep) {
1106                         /*
1107                          * To avoid race condition with ffs_epfile_io_complete,
1108                          * dequeue the request first then check
1109                          * status. usb_ep_dequeue API should guarantee no race
1110                          * condition with req->complete callback.
1111                          */
1112                         usb_ep_dequeue(ep->ep, req);
1113                         wait_for_completion(&done);
1114                         interrupted = ep->status < 0;
1115                 }
1116
1117                 if (epfile->ep != ep) {
1118                         /* In the meantime, endpoint got disabled or changed. */
1119                         ret = -ESHUTDOWN;
1120                         goto error_mutex;
1121                 }
1122
1123                 if (interrupted)
1124                         ret = -EINTR;
1125                 else if (io_data->read && ep->status > 0)
1126                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1127                                                      &io_data->data);
1128                 else
1129                         ret = ep->status;
1130                 goto error_mutex;
1131         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1132                 ret = -ENOMEM;
1133         } else {
1134                 if (io_data->use_sg) {
1135                         req->buf = NULL;
1136                         req->sg = io_data->sgt.sgl;
1137                         req->num_sgs = io_data->sgt.nents;
1138                 } else {
1139                         req->buf = data;
1140                         req->num_sgs = 0;
1141                 }
1142                 req->length = data_len;
1143
1144                 io_data->buf = data;
1145                 io_data->ep = ep->ep;
1146                 io_data->req = req;
1147                 io_data->ffs = epfile->ffs;
1148
1149                 req->context  = io_data;
1150                 req->complete = ffs_epfile_async_io_complete;
1151
1152                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1153                 if (unlikely(ret)) {
1154                         io_data->req = NULL;
1155                         usb_ep_free_request(ep->ep, req);
1156                         goto error_lock;
1157                 }
1158
1159                 ret = -EIOCBQUEUED;
1160                 /*
1161                  * Do not kfree the buffer in this function.  It will be freed
1162                  * by ffs_user_copy_worker.
1163                  */
1164                 data = NULL;
1165         }
1166
1167 error_lock:
1168         spin_unlock_irq(&epfile->ffs->eps_lock);
1169 error_mutex:
1170         mutex_unlock(&epfile->mutex);
1171 error:
1172         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1173                 ffs_free_buffer(io_data);
1174         return ret;
1175 }
1176
1177 static int
1178 ffs_epfile_open(struct inode *inode, struct file *file)
1179 {
1180         struct ffs_epfile *epfile = inode->i_private;
1181
1182         ENTER();
1183
1184         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1185                 return -ENODEV;
1186
1187         file->private_data = epfile;
1188         ffs_data_opened(epfile->ffs);
1189
1190         return 0;
1191 }
1192
1193 static int ffs_aio_cancel(struct kiocb *kiocb)
1194 {
1195         struct ffs_io_data *io_data = kiocb->private;
1196         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1197         unsigned long flags;
1198         int value;
1199
1200         ENTER();
1201
1202         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1203
1204         if (likely(io_data && io_data->ep && io_data->req))
1205                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1206         else
1207                 value = -EINVAL;
1208
1209         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1210
1211         return value;
1212 }
1213
1214 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1215 {
1216         struct ffs_io_data io_data, *p = &io_data;
1217         ssize_t res;
1218
1219         ENTER();
1220
1221         if (!is_sync_kiocb(kiocb)) {
1222                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1223                 if (unlikely(!p))
1224                         return -ENOMEM;
1225                 p->aio = true;
1226         } else {
1227                 memset(p, 0, sizeof(*p));
1228                 p->aio = false;
1229         }
1230
1231         p->read = false;
1232         p->kiocb = kiocb;
1233         p->data = *from;
1234         p->mm = current->mm;
1235
1236         kiocb->private = p;
1237
1238         if (p->aio)
1239                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1240
1241         res = ffs_epfile_io(kiocb->ki_filp, p);
1242         if (res == -EIOCBQUEUED)
1243                 return res;
1244         if (p->aio)
1245                 kfree(p);
1246         else
1247                 *from = p->data;
1248         return res;
1249 }
1250
1251 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1252 {
1253         struct ffs_io_data io_data, *p = &io_data;
1254         ssize_t res;
1255
1256         ENTER();
1257
1258         if (!is_sync_kiocb(kiocb)) {
1259                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1260                 if (unlikely(!p))
1261                         return -ENOMEM;
1262                 p->aio = true;
1263         } else {
1264                 memset(p, 0, sizeof(*p));
1265                 p->aio = false;
1266         }
1267
1268         p->read = true;
1269         p->kiocb = kiocb;
1270         if (p->aio) {
1271                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1272                 if (!p->to_free) {
1273                         kfree(p);
1274                         return -ENOMEM;
1275                 }
1276         } else {
1277                 p->data = *to;
1278                 p->to_free = NULL;
1279         }
1280         p->mm = current->mm;
1281
1282         kiocb->private = p;
1283
1284         if (p->aio)
1285                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1286
1287         res = ffs_epfile_io(kiocb->ki_filp, p);
1288         if (res == -EIOCBQUEUED)
1289                 return res;
1290
1291         if (p->aio) {
1292                 kfree(p->to_free);
1293                 kfree(p);
1294         } else {
1295                 *to = p->data;
1296         }
1297         return res;
1298 }
1299
1300 static int
1301 ffs_epfile_release(struct inode *inode, struct file *file)
1302 {
1303         struct ffs_epfile *epfile = inode->i_private;
1304
1305         ENTER();
1306
1307         __ffs_epfile_read_buffer_free(epfile);
1308         ffs_data_closed(epfile->ffs);
1309
1310         return 0;
1311 }
1312
1313 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1314                              unsigned long value)
1315 {
1316         struct ffs_epfile *epfile = file->private_data;
1317         struct ffs_ep *ep;
1318         int ret;
1319
1320         ENTER();
1321
1322         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1323                 return -ENODEV;
1324
1325         /* Wait for endpoint to be enabled */
1326         ep = epfile->ep;
1327         if (!ep) {
1328                 if (file->f_flags & O_NONBLOCK)
1329                         return -EAGAIN;
1330
1331                 ret = wait_event_interruptible(
1332                                 epfile->ffs->wait, (ep = epfile->ep));
1333                 if (ret)
1334                         return -EINTR;
1335         }
1336
1337         spin_lock_irq(&epfile->ffs->eps_lock);
1338
1339         /* In the meantime, endpoint got disabled or changed. */
1340         if (epfile->ep != ep) {
1341                 spin_unlock_irq(&epfile->ffs->eps_lock);
1342                 return -ESHUTDOWN;
1343         }
1344
1345         switch (code) {
1346         case FUNCTIONFS_FIFO_STATUS:
1347                 ret = usb_ep_fifo_status(epfile->ep->ep);
1348                 break;
1349         case FUNCTIONFS_FIFO_FLUSH:
1350                 usb_ep_fifo_flush(epfile->ep->ep);
1351                 ret = 0;
1352                 break;
1353         case FUNCTIONFS_CLEAR_HALT:
1354                 ret = usb_ep_clear_halt(epfile->ep->ep);
1355                 break;
1356         case FUNCTIONFS_ENDPOINT_REVMAP:
1357                 ret = epfile->ep->num;
1358                 break;
1359         case FUNCTIONFS_ENDPOINT_DESC:
1360         {
1361                 int desc_idx;
1362                 struct usb_endpoint_descriptor *desc;
1363
1364                 switch (epfile->ffs->gadget->speed) {
1365                 case USB_SPEED_SUPER:
1366                         desc_idx = 2;
1367                         break;
1368                 case USB_SPEED_HIGH:
1369                         desc_idx = 1;
1370                         break;
1371                 default:
1372                         desc_idx = 0;
1373                 }
1374                 desc = epfile->ep->descs[desc_idx];
1375
1376                 spin_unlock_irq(&epfile->ffs->eps_lock);
1377                 ret = copy_to_user((void __user *)value, desc, desc->bLength);
1378                 if (ret)
1379                         ret = -EFAULT;
1380                 return ret;
1381         }
1382         default:
1383                 ret = -ENOTTY;
1384         }
1385         spin_unlock_irq(&epfile->ffs->eps_lock);
1386
1387         return ret;
1388 }
1389
1390 #ifdef CONFIG_COMPAT
1391 static long ffs_epfile_compat_ioctl(struct file *file, unsigned code,
1392                 unsigned long value)
1393 {
1394         return ffs_epfile_ioctl(file, code, value);
1395 }
1396 #endif
1397
1398 static const struct file_operations ffs_epfile_operations = {
1399         .llseek =       no_llseek,
1400
1401         .open =         ffs_epfile_open,
1402         .write_iter =   ffs_epfile_write_iter,
1403         .read_iter =    ffs_epfile_read_iter,
1404         .release =      ffs_epfile_release,
1405         .unlocked_ioctl =       ffs_epfile_ioctl,
1406 #ifdef CONFIG_COMPAT
1407         .compat_ioctl = ffs_epfile_compat_ioctl,
1408 #endif
1409 };
1410
1411
1412 /* File system and super block operations ***********************************/
1413
1414 /*
1415  * Mounting the file system creates a controller file, used first for
1416  * function configuration then later for event monitoring.
1417  */
1418
1419 static struct inode *__must_check
1420 ffs_sb_make_inode(struct super_block *sb, void *data,
1421                   const struct file_operations *fops,
1422                   const struct inode_operations *iops,
1423                   struct ffs_file_perms *perms)
1424 {
1425         struct inode *inode;
1426
1427         ENTER();
1428
1429         inode = new_inode(sb);
1430
1431         if (likely(inode)) {
1432                 struct timespec64 ts = current_time(inode);
1433
1434                 inode->i_ino     = get_next_ino();
1435                 inode->i_mode    = perms->mode;
1436                 inode->i_uid     = perms->uid;
1437                 inode->i_gid     = perms->gid;
1438                 inode->i_atime   = ts;
1439                 inode->i_mtime   = ts;
1440                 inode->i_ctime   = ts;
1441                 inode->i_private = data;
1442                 if (fops)
1443                         inode->i_fop = fops;
1444                 if (iops)
1445                         inode->i_op  = iops;
1446         }
1447
1448         return inode;
1449 }
1450
1451 /* Create "regular" file */
1452 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1453                                         const char *name, void *data,
1454                                         const struct file_operations *fops)
1455 {
1456         struct ffs_data *ffs = sb->s_fs_info;
1457         struct dentry   *dentry;
1458         struct inode    *inode;
1459
1460         ENTER();
1461
1462         dentry = d_alloc_name(sb->s_root, name);
1463         if (unlikely(!dentry))
1464                 return NULL;
1465
1466         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1467         if (unlikely(!inode)) {
1468                 dput(dentry);
1469                 return NULL;
1470         }
1471
1472         d_add(dentry, inode);
1473         return dentry;
1474 }
1475
1476 /* Super block */
1477 static const struct super_operations ffs_sb_operations = {
1478         .statfs =       simple_statfs,
1479         .drop_inode =   generic_delete_inode,
1480 };
1481
1482 struct ffs_sb_fill_data {
1483         struct ffs_file_perms perms;
1484         umode_t root_mode;
1485         const char *dev_name;
1486         bool no_disconnect;
1487         struct ffs_data *ffs_data;
1488 };
1489
1490 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1491 {
1492         struct ffs_sb_fill_data *data = fc->fs_private;
1493         struct inode    *inode;
1494         struct ffs_data *ffs = data->ffs_data;
1495
1496         ENTER();
1497
1498         ffs->sb              = sb;
1499         data->ffs_data       = NULL;
1500         sb->s_fs_info        = ffs;
1501         sb->s_blocksize      = PAGE_SIZE;
1502         sb->s_blocksize_bits = PAGE_SHIFT;
1503         sb->s_magic          = FUNCTIONFS_MAGIC;
1504         sb->s_op             = &ffs_sb_operations;
1505         sb->s_time_gran      = 1;
1506
1507         /* Root inode */
1508         data->perms.mode = data->root_mode;
1509         inode = ffs_sb_make_inode(sb, NULL,
1510                                   &simple_dir_operations,
1511                                   &simple_dir_inode_operations,
1512                                   &data->perms);
1513         sb->s_root = d_make_root(inode);
1514         if (unlikely(!sb->s_root))
1515                 return -ENOMEM;
1516
1517         /* EP0 file */
1518         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1519                                          &ffs_ep0_operations)))
1520                 return -ENOMEM;
1521
1522         return 0;
1523 }
1524
1525 enum {
1526         Opt_no_disconnect,
1527         Opt_rmode,
1528         Opt_fmode,
1529         Opt_mode,
1530         Opt_uid,
1531         Opt_gid,
1532 };
1533
1534 static const struct fs_parameter_spec ffs_fs_param_specs[] = {
1535         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1536         fsparam_u32     ("rmode",               Opt_rmode),
1537         fsparam_u32     ("fmode",               Opt_fmode),
1538         fsparam_u32     ("mode",                Opt_mode),
1539         fsparam_u32     ("uid",                 Opt_uid),
1540         fsparam_u32     ("gid",                 Opt_gid),
1541         {}
1542 };
1543
1544 static const struct fs_parameter_description ffs_fs_fs_parameters = {
1545         .name           = "kAFS",
1546         .specs          = ffs_fs_param_specs,
1547 };
1548
1549 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1550 {
1551         struct ffs_sb_fill_data *data = fc->fs_private;
1552         struct fs_parse_result result;
1553         int opt;
1554
1555         ENTER();
1556
1557         opt = fs_parse(fc, &ffs_fs_fs_parameters, param, &result);
1558         if (opt < 0)
1559                 return opt;
1560
1561         switch (opt) {
1562         case Opt_no_disconnect:
1563                 data->no_disconnect = result.boolean;
1564                 break;
1565         case Opt_rmode:
1566                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1567                 break;
1568         case Opt_fmode:
1569                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1570                 break;
1571         case Opt_mode:
1572                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1573                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1574                 break;
1575
1576         case Opt_uid:
1577                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1578                 if (!uid_valid(data->perms.uid))
1579                         goto unmapped_value;
1580                 break;
1581         case Opt_gid:
1582                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1583                 if (!gid_valid(data->perms.gid))
1584                         goto unmapped_value;
1585                 break;
1586
1587         default:
1588                 return -ENOPARAM;
1589         }
1590
1591         return 0;
1592
1593 unmapped_value:
1594         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1595 }
1596
1597 /*
1598  * Set up the superblock for a mount.
1599  */
1600 static int ffs_fs_get_tree(struct fs_context *fc)
1601 {
1602         struct ffs_sb_fill_data *ctx = fc->fs_private;
1603         void *ffs_dev;
1604         struct ffs_data *ffs;
1605
1606         ENTER();
1607
1608         if (!fc->source)
1609                 return invalf(fc, "No source specified");
1610
1611         ffs = ffs_data_new(fc->source);
1612         if (unlikely(!ffs))
1613                 return -ENOMEM;
1614         ffs->file_perms = ctx->perms;
1615         ffs->no_disconnect = ctx->no_disconnect;
1616
1617         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1618         if (unlikely(!ffs->dev_name)) {
1619                 ffs_data_put(ffs);
1620                 return -ENOMEM;
1621         }
1622
1623         ffs_dev = ffs_acquire_dev(ffs->dev_name);
1624         if (IS_ERR(ffs_dev)) {
1625                 ffs_data_put(ffs);
1626                 return PTR_ERR(ffs_dev);
1627         }
1628
1629         ffs->private_data = ffs_dev;
1630         ctx->ffs_data = ffs;
1631         return get_tree_nodev(fc, ffs_sb_fill);
1632 }
1633
1634 static void ffs_fs_free_fc(struct fs_context *fc)
1635 {
1636         struct ffs_sb_fill_data *ctx = fc->fs_private;
1637
1638         if (ctx) {
1639                 if (ctx->ffs_data) {
1640                         ffs_release_dev(ctx->ffs_data);
1641                         ffs_data_put(ctx->ffs_data);
1642                 }
1643
1644                 kfree(ctx);
1645         }
1646 }
1647
1648 static const struct fs_context_operations ffs_fs_context_ops = {
1649         .free           = ffs_fs_free_fc,
1650         .parse_param    = ffs_fs_parse_param,
1651         .get_tree       = ffs_fs_get_tree,
1652 };
1653
1654 static int ffs_fs_init_fs_context(struct fs_context *fc)
1655 {
1656         struct ffs_sb_fill_data *ctx;
1657
1658         ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1659         if (!ctx)
1660                 return -ENOMEM;
1661
1662         ctx->perms.mode = S_IFREG | 0600;
1663         ctx->perms.uid = GLOBAL_ROOT_UID;
1664         ctx->perms.gid = GLOBAL_ROOT_GID;
1665         ctx->root_mode = S_IFDIR | 0500;
1666         ctx->no_disconnect = false;
1667
1668         fc->fs_private = ctx;
1669         fc->ops = &ffs_fs_context_ops;
1670         return 0;
1671 }
1672
1673 static void
1674 ffs_fs_kill_sb(struct super_block *sb)
1675 {
1676         ENTER();
1677
1678         kill_litter_super(sb);
1679         if (sb->s_fs_info) {
1680                 ffs_release_dev(sb->s_fs_info);
1681                 ffs_data_closed(sb->s_fs_info);
1682         }
1683 }
1684
1685 static struct file_system_type ffs_fs_type = {
1686         .owner          = THIS_MODULE,
1687         .name           = "functionfs",
1688         .init_fs_context = ffs_fs_init_fs_context,
1689         .parameters     = &ffs_fs_fs_parameters,
1690         .kill_sb        = ffs_fs_kill_sb,
1691 };
1692 MODULE_ALIAS_FS("functionfs");
1693
1694
1695 /* Driver's main init/cleanup functions *************************************/
1696
1697 static int functionfs_init(void)
1698 {
1699         int ret;
1700
1701         ENTER();
1702
1703         ret = register_filesystem(&ffs_fs_type);
1704         if (likely(!ret))
1705                 pr_info("file system registered\n");
1706         else
1707                 pr_err("failed registering file system (%d)\n", ret);
1708
1709         return ret;
1710 }
1711
1712 static void functionfs_cleanup(void)
1713 {
1714         ENTER();
1715
1716         pr_info("unloading\n");
1717         unregister_filesystem(&ffs_fs_type);
1718 }
1719
1720
1721 /* ffs_data and ffs_function construction and destruction code **************/
1722
1723 static void ffs_data_clear(struct ffs_data *ffs);
1724 static void ffs_data_reset(struct ffs_data *ffs);
1725
1726 static void ffs_data_get(struct ffs_data *ffs)
1727 {
1728         ENTER();
1729
1730         refcount_inc(&ffs->ref);
1731 }
1732
1733 static void ffs_data_opened(struct ffs_data *ffs)
1734 {
1735         ENTER();
1736
1737         refcount_inc(&ffs->ref);
1738         if (atomic_add_return(1, &ffs->opened) == 1 &&
1739                         ffs->state == FFS_DEACTIVATED) {
1740                 ffs->state = FFS_CLOSING;
1741                 ffs_data_reset(ffs);
1742         }
1743 }
1744
1745 static void ffs_data_put(struct ffs_data *ffs)
1746 {
1747         ENTER();
1748
1749         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1750                 pr_info("%s(): freeing\n", __func__);
1751                 ffs_data_clear(ffs);
1752                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1753                        waitqueue_active(&ffs->ep0req_completion.wait) ||
1754                        waitqueue_active(&ffs->wait));
1755                 destroy_workqueue(ffs->io_completion_wq);
1756                 kfree(ffs->dev_name);
1757                 kfree(ffs);
1758         }
1759 }
1760
1761 static void ffs_data_closed(struct ffs_data *ffs)
1762 {
1763         ENTER();
1764
1765         if (atomic_dec_and_test(&ffs->opened)) {
1766                 if (ffs->no_disconnect) {
1767                         ffs->state = FFS_DEACTIVATED;
1768                         if (ffs->epfiles) {
1769                                 ffs_epfiles_destroy(ffs->epfiles,
1770                                                    ffs->eps_count);
1771                                 ffs->epfiles = NULL;
1772                         }
1773                         if (ffs->setup_state == FFS_SETUP_PENDING)
1774                                 __ffs_ep0_stall(ffs);
1775                 } else {
1776                         ffs->state = FFS_CLOSING;
1777                         ffs_data_reset(ffs);
1778                 }
1779         }
1780         if (atomic_read(&ffs->opened) < 0) {
1781                 ffs->state = FFS_CLOSING;
1782                 ffs_data_reset(ffs);
1783         }
1784
1785         ffs_data_put(ffs);
1786 }
1787
1788 static struct ffs_data *ffs_data_new(const char *dev_name)
1789 {
1790         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1791         if (unlikely(!ffs))
1792                 return NULL;
1793
1794         ENTER();
1795
1796         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1797         if (!ffs->io_completion_wq) {
1798                 kfree(ffs);
1799                 return NULL;
1800         }
1801
1802         refcount_set(&ffs->ref, 1);
1803         atomic_set(&ffs->opened, 0);
1804         ffs->state = FFS_READ_DESCRIPTORS;
1805         mutex_init(&ffs->mutex);
1806         spin_lock_init(&ffs->eps_lock);
1807         init_waitqueue_head(&ffs->ev.waitq);
1808         init_waitqueue_head(&ffs->wait);
1809         init_completion(&ffs->ep0req_completion);
1810
1811         /* XXX REVISIT need to update it in some places, or do we? */
1812         ffs->ev.can_stall = 1;
1813
1814         return ffs;
1815 }
1816
1817 static void ffs_data_clear(struct ffs_data *ffs)
1818 {
1819         ENTER();
1820
1821         ffs_closed(ffs);
1822
1823         BUG_ON(ffs->gadget);
1824
1825         if (ffs->epfiles)
1826                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1827
1828         if (ffs->ffs_eventfd)
1829                 eventfd_ctx_put(ffs->ffs_eventfd);
1830
1831         kfree(ffs->raw_descs_data);
1832         kfree(ffs->raw_strings);
1833         kfree(ffs->stringtabs);
1834 }
1835
1836 static void ffs_data_reset(struct ffs_data *ffs)
1837 {
1838         ENTER();
1839
1840         ffs_data_clear(ffs);
1841
1842         ffs->epfiles = NULL;
1843         ffs->raw_descs_data = NULL;
1844         ffs->raw_descs = NULL;
1845         ffs->raw_strings = NULL;
1846         ffs->stringtabs = NULL;
1847
1848         ffs->raw_descs_length = 0;
1849         ffs->fs_descs_count = 0;
1850         ffs->hs_descs_count = 0;
1851         ffs->ss_descs_count = 0;
1852
1853         ffs->strings_count = 0;
1854         ffs->interfaces_count = 0;
1855         ffs->eps_count = 0;
1856
1857         ffs->ev.count = 0;
1858
1859         ffs->state = FFS_READ_DESCRIPTORS;
1860         ffs->setup_state = FFS_NO_SETUP;
1861         ffs->flags = 0;
1862
1863         ffs->ms_os_descs_ext_prop_count = 0;
1864         ffs->ms_os_descs_ext_prop_name_len = 0;
1865         ffs->ms_os_descs_ext_prop_data_len = 0;
1866 }
1867
1868
1869 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1870 {
1871         struct usb_gadget_strings **lang;
1872         int first_id;
1873
1874         ENTER();
1875
1876         if (WARN_ON(ffs->state != FFS_ACTIVE
1877                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1878                 return -EBADFD;
1879
1880         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1881         if (unlikely(first_id < 0))
1882                 return first_id;
1883
1884         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1885         if (unlikely(!ffs->ep0req))
1886                 return -ENOMEM;
1887         ffs->ep0req->complete = ffs_ep0_complete;
1888         ffs->ep0req->context = ffs;
1889
1890         lang = ffs->stringtabs;
1891         if (lang) {
1892                 for (; *lang; ++lang) {
1893                         struct usb_string *str = (*lang)->strings;
1894                         int id = first_id;
1895                         for (; str->s; ++id, ++str)
1896                                 str->id = id;
1897                 }
1898         }
1899
1900         ffs->gadget = cdev->gadget;
1901         ffs_data_get(ffs);
1902         return 0;
1903 }
1904
1905 static void functionfs_unbind(struct ffs_data *ffs)
1906 {
1907         ENTER();
1908
1909         if (!WARN_ON(!ffs->gadget)) {
1910                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1911                 ffs->ep0req = NULL;
1912                 ffs->gadget = NULL;
1913                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1914                 ffs_data_put(ffs);
1915         }
1916 }
1917
1918 static int ffs_epfiles_create(struct ffs_data *ffs)
1919 {
1920         struct ffs_epfile *epfile, *epfiles;
1921         unsigned i, count;
1922
1923         ENTER();
1924
1925         count = ffs->eps_count;
1926         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1927         if (!epfiles)
1928                 return -ENOMEM;
1929
1930         epfile = epfiles;
1931         for (i = 1; i <= count; ++i, ++epfile) {
1932                 epfile->ffs = ffs;
1933                 mutex_init(&epfile->mutex);
1934                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1935                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1936                 else
1937                         sprintf(epfile->name, "ep%u", i);
1938                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1939                                                  epfile,
1940                                                  &ffs_epfile_operations);
1941                 if (unlikely(!epfile->dentry)) {
1942                         ffs_epfiles_destroy(epfiles, i - 1);
1943                         return -ENOMEM;
1944                 }
1945         }
1946
1947         ffs->epfiles = epfiles;
1948         return 0;
1949 }
1950
1951 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1952 {
1953         struct ffs_epfile *epfile = epfiles;
1954
1955         ENTER();
1956
1957         for (; count; --count, ++epfile) {
1958                 BUG_ON(mutex_is_locked(&epfile->mutex));
1959                 if (epfile->dentry) {
1960                         d_delete(epfile->dentry);
1961                         dput(epfile->dentry);
1962                         epfile->dentry = NULL;
1963                 }
1964         }
1965
1966         kfree(epfiles);
1967 }
1968
1969 static void ffs_func_eps_disable(struct ffs_function *func)
1970 {
1971         struct ffs_ep *ep         = func->eps;
1972         struct ffs_epfile *epfile = func->ffs->epfiles;
1973         unsigned count            = func->ffs->eps_count;
1974         unsigned long flags;
1975
1976         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1977         while (count--) {
1978                 /* pending requests get nuked */
1979                 if (likely(ep->ep))
1980                         usb_ep_disable(ep->ep);
1981                 ++ep;
1982
1983                 if (epfile) {
1984                         epfile->ep = NULL;
1985                         __ffs_epfile_read_buffer_free(epfile);
1986                         ++epfile;
1987                 }
1988         }
1989         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1990 }
1991
1992 static int ffs_func_eps_enable(struct ffs_function *func)
1993 {
1994         struct ffs_data *ffs      = func->ffs;
1995         struct ffs_ep *ep         = func->eps;
1996         struct ffs_epfile *epfile = ffs->epfiles;
1997         unsigned count            = ffs->eps_count;
1998         unsigned long flags;
1999         int ret = 0;
2000
2001         spin_lock_irqsave(&func->ffs->eps_lock, flags);
2002         while(count--) {
2003                 ep->ep->driver_data = ep;
2004
2005                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
2006                 if (ret) {
2007                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
2008                                         __func__, ep->ep->name, ret);
2009                         break;
2010                 }
2011
2012                 ret = usb_ep_enable(ep->ep);
2013                 if (likely(!ret)) {
2014                         epfile->ep = ep;
2015                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
2016                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
2017                 } else {
2018                         break;
2019                 }
2020
2021                 ++ep;
2022                 ++epfile;
2023         }
2024
2025         wake_up_interruptible(&ffs->wait);
2026         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2027
2028         return ret;
2029 }
2030
2031
2032 /* Parsing and building descriptors and strings *****************************/
2033
2034 /*
2035  * This validates if data pointed by data is a valid USB descriptor as
2036  * well as record how many interfaces, endpoints and strings are
2037  * required by given configuration.  Returns address after the
2038  * descriptor or NULL if data is invalid.
2039  */
2040
2041 enum ffs_entity_type {
2042         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
2043 };
2044
2045 enum ffs_os_desc_type {
2046         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
2047 };
2048
2049 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2050                                    u8 *valuep,
2051                                    struct usb_descriptor_header *desc,
2052                                    void *priv);
2053
2054 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2055                                     struct usb_os_desc_header *h, void *data,
2056                                     unsigned len, void *priv);
2057
2058 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2059                                            ffs_entity_callback entity,
2060                                            void *priv, int *current_class)
2061 {
2062         struct usb_descriptor_header *_ds = (void *)data;
2063         u8 length;
2064         int ret;
2065
2066         ENTER();
2067
2068         /* At least two bytes are required: length and type */
2069         if (len < 2) {
2070                 pr_vdebug("descriptor too short\n");
2071                 return -EINVAL;
2072         }
2073
2074         /* If we have at least as many bytes as the descriptor takes? */
2075         length = _ds->bLength;
2076         if (len < length) {
2077                 pr_vdebug("descriptor longer then available data\n");
2078                 return -EINVAL;
2079         }
2080
2081 #define __entity_check_INTERFACE(val)  1
2082 #define __entity_check_STRING(val)     (val)
2083 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2084 #define __entity(type, val) do {                                        \
2085                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2086                 if (unlikely(!__entity_check_ ##type(val))) {           \
2087                         pr_vdebug("invalid entity's value\n");          \
2088                         return -EINVAL;                                 \
2089                 }                                                       \
2090                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2091                 if (unlikely(ret < 0)) {                                \
2092                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2093                                  (val), ret);                           \
2094                         return ret;                                     \
2095                 }                                                       \
2096         } while (0)
2097
2098         /* Parse descriptor depending on type. */
2099         switch (_ds->bDescriptorType) {
2100         case USB_DT_DEVICE:
2101         case USB_DT_CONFIG:
2102         case USB_DT_STRING:
2103         case USB_DT_DEVICE_QUALIFIER:
2104                 /* function can't have any of those */
2105                 pr_vdebug("descriptor reserved for gadget: %d\n",
2106                       _ds->bDescriptorType);
2107                 return -EINVAL;
2108
2109         case USB_DT_INTERFACE: {
2110                 struct usb_interface_descriptor *ds = (void *)_ds;
2111                 pr_vdebug("interface descriptor\n");
2112                 if (length != sizeof *ds)
2113                         goto inv_length;
2114
2115                 __entity(INTERFACE, ds->bInterfaceNumber);
2116                 if (ds->iInterface)
2117                         __entity(STRING, ds->iInterface);
2118                 *current_class = ds->bInterfaceClass;
2119         }
2120                 break;
2121
2122         case USB_DT_ENDPOINT: {
2123                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2124                 pr_vdebug("endpoint descriptor\n");
2125                 if (length != USB_DT_ENDPOINT_SIZE &&
2126                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2127                         goto inv_length;
2128                 __entity(ENDPOINT, ds->bEndpointAddress);
2129         }
2130                 break;
2131
2132         case USB_TYPE_CLASS | 0x01:
2133                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2134                         pr_vdebug("hid descriptor\n");
2135                         if (length != sizeof(struct hid_descriptor))
2136                                 goto inv_length;
2137                         break;
2138                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2139                         pr_vdebug("ccid descriptor\n");
2140                         if (length != sizeof(struct ccid_descriptor))
2141                                 goto inv_length;
2142                         break;
2143                 } else {
2144                         pr_vdebug("unknown descriptor: %d for class %d\n",
2145                               _ds->bDescriptorType, *current_class);
2146                         return -EINVAL;
2147                 }
2148
2149         case USB_DT_OTG:
2150                 if (length != sizeof(struct usb_otg_descriptor))
2151                         goto inv_length;
2152                 break;
2153
2154         case USB_DT_INTERFACE_ASSOCIATION: {
2155                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2156                 pr_vdebug("interface association descriptor\n");
2157                 if (length != sizeof *ds)
2158                         goto inv_length;
2159                 if (ds->iFunction)
2160                         __entity(STRING, ds->iFunction);
2161         }
2162                 break;
2163
2164         case USB_DT_SS_ENDPOINT_COMP:
2165                 pr_vdebug("EP SS companion descriptor\n");
2166                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2167                         goto inv_length;
2168                 break;
2169
2170         case USB_DT_OTHER_SPEED_CONFIG:
2171         case USB_DT_INTERFACE_POWER:
2172         case USB_DT_DEBUG:
2173         case USB_DT_SECURITY:
2174         case USB_DT_CS_RADIO_CONTROL:
2175                 /* TODO */
2176                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2177                 return -EINVAL;
2178
2179         default:
2180                 /* We should never be here */
2181                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2182                 return -EINVAL;
2183
2184 inv_length:
2185                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2186                           _ds->bLength, _ds->bDescriptorType);
2187                 return -EINVAL;
2188         }
2189
2190 #undef __entity
2191 #undef __entity_check_DESCRIPTOR
2192 #undef __entity_check_INTERFACE
2193 #undef __entity_check_STRING
2194 #undef __entity_check_ENDPOINT
2195
2196         return length;
2197 }
2198
2199 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2200                                      ffs_entity_callback entity, void *priv)
2201 {
2202         const unsigned _len = len;
2203         unsigned long num = 0;
2204         int current_class = -1;
2205
2206         ENTER();
2207
2208         for (;;) {
2209                 int ret;
2210
2211                 if (num == count)
2212                         data = NULL;
2213
2214                 /* Record "descriptor" entity */
2215                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2216                 if (unlikely(ret < 0)) {
2217                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2218                                  num, ret);
2219                         return ret;
2220                 }
2221
2222                 if (!data)
2223                         return _len - len;
2224
2225                 ret = ffs_do_single_desc(data, len, entity, priv,
2226                         &current_class);
2227                 if (unlikely(ret < 0)) {
2228                         pr_debug("%s returns %d\n", __func__, ret);
2229                         return ret;
2230                 }
2231
2232                 len -= ret;
2233                 data += ret;
2234                 ++num;
2235         }
2236 }
2237
2238 static int __ffs_data_do_entity(enum ffs_entity_type type,
2239                                 u8 *valuep, struct usb_descriptor_header *desc,
2240                                 void *priv)
2241 {
2242         struct ffs_desc_helper *helper = priv;
2243         struct usb_endpoint_descriptor *d;
2244
2245         ENTER();
2246
2247         switch (type) {
2248         case FFS_DESCRIPTOR:
2249                 break;
2250
2251         case FFS_INTERFACE:
2252                 /*
2253                  * Interfaces are indexed from zero so if we
2254                  * encountered interface "n" then there are at least
2255                  * "n+1" interfaces.
2256                  */
2257                 if (*valuep >= helper->interfaces_count)
2258                         helper->interfaces_count = *valuep + 1;
2259                 break;
2260
2261         case FFS_STRING:
2262                 /*
2263                  * Strings are indexed from 1 (0 is reserved
2264                  * for languages list)
2265                  */
2266                 if (*valuep > helper->ffs->strings_count)
2267                         helper->ffs->strings_count = *valuep;
2268                 break;
2269
2270         case FFS_ENDPOINT:
2271                 d = (void *)desc;
2272                 helper->eps_count++;
2273                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2274                         return -EINVAL;
2275                 /* Check if descriptors for any speed were already parsed */
2276                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2277                         helper->ffs->eps_addrmap[helper->eps_count] =
2278                                 d->bEndpointAddress;
2279                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2280                                 d->bEndpointAddress)
2281                         return -EINVAL;
2282                 break;
2283         }
2284
2285         return 0;
2286 }
2287
2288 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2289                                    struct usb_os_desc_header *desc)
2290 {
2291         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2292         u16 w_index = le16_to_cpu(desc->wIndex);
2293
2294         if (bcd_version != 1) {
2295                 pr_vdebug("unsupported os descriptors version: %d",
2296                           bcd_version);
2297                 return -EINVAL;
2298         }
2299         switch (w_index) {
2300         case 0x4:
2301                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2302                 break;
2303         case 0x5:
2304                 *next_type = FFS_OS_DESC_EXT_PROP;
2305                 break;
2306         default:
2307                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2308                 return -EINVAL;
2309         }
2310
2311         return sizeof(*desc);
2312 }
2313
2314 /*
2315  * Process all extended compatibility/extended property descriptors
2316  * of a feature descriptor
2317  */
2318 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2319                                               enum ffs_os_desc_type type,
2320                                               u16 feature_count,
2321                                               ffs_os_desc_callback entity,
2322                                               void *priv,
2323                                               struct usb_os_desc_header *h)
2324 {
2325         int ret;
2326         const unsigned _len = len;
2327
2328         ENTER();
2329
2330         /* loop over all ext compat/ext prop descriptors */
2331         while (feature_count--) {
2332                 ret = entity(type, h, data, len, priv);
2333                 if (unlikely(ret < 0)) {
2334                         pr_debug("bad OS descriptor, type: %d\n", type);
2335                         return ret;
2336                 }
2337                 data += ret;
2338                 len -= ret;
2339         }
2340         return _len - len;
2341 }
2342
2343 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2344 static int __must_check ffs_do_os_descs(unsigned count,
2345                                         char *data, unsigned len,
2346                                         ffs_os_desc_callback entity, void *priv)
2347 {
2348         const unsigned _len = len;
2349         unsigned long num = 0;
2350
2351         ENTER();
2352
2353         for (num = 0; num < count; ++num) {
2354                 int ret;
2355                 enum ffs_os_desc_type type;
2356                 u16 feature_count;
2357                 struct usb_os_desc_header *desc = (void *)data;
2358
2359                 if (len < sizeof(*desc))
2360                         return -EINVAL;
2361
2362                 /*
2363                  * Record "descriptor" entity.
2364                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2365                  * Move the data pointer to the beginning of extended
2366                  * compatibilities proper or extended properties proper
2367                  * portions of the data
2368                  */
2369                 if (le32_to_cpu(desc->dwLength) > len)
2370                         return -EINVAL;
2371
2372                 ret = __ffs_do_os_desc_header(&type, desc);
2373                 if (unlikely(ret < 0)) {
2374                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2375                                  num, ret);
2376                         return ret;
2377                 }
2378                 /*
2379                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2380                  */
2381                 feature_count = le16_to_cpu(desc->wCount);
2382                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2383                     (feature_count > 255 || desc->Reserved))
2384                                 return -EINVAL;
2385                 len -= ret;
2386                 data += ret;
2387
2388                 /*
2389                  * Process all function/property descriptors
2390                  * of this Feature Descriptor
2391                  */
2392                 ret = ffs_do_single_os_desc(data, len, type,
2393                                             feature_count, entity, priv, desc);
2394                 if (unlikely(ret < 0)) {
2395                         pr_debug("%s returns %d\n", __func__, ret);
2396                         return ret;
2397                 }
2398
2399                 len -= ret;
2400                 data += ret;
2401         }
2402         return _len - len;
2403 }
2404
2405 /**
2406  * Validate contents of the buffer from userspace related to OS descriptors.
2407  */
2408 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2409                                  struct usb_os_desc_header *h, void *data,
2410                                  unsigned len, void *priv)
2411 {
2412         struct ffs_data *ffs = priv;
2413         u8 length;
2414
2415         ENTER();
2416
2417         switch (type) {
2418         case FFS_OS_DESC_EXT_COMPAT: {
2419                 struct usb_ext_compat_desc *d = data;
2420                 int i;
2421
2422                 if (len < sizeof(*d) ||
2423                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2424                         return -EINVAL;
2425                 if (d->Reserved1 != 1) {
2426                         /*
2427                          * According to the spec, Reserved1 must be set to 1
2428                          * but older kernels incorrectly rejected non-zero
2429                          * values.  We fix it here to avoid returning EINVAL
2430                          * in response to values we used to accept.
2431                          */
2432                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2433                         d->Reserved1 = 1;
2434                 }
2435                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2436                         if (d->Reserved2[i])
2437                                 return -EINVAL;
2438
2439                 length = sizeof(struct usb_ext_compat_desc);
2440         }
2441                 break;
2442         case FFS_OS_DESC_EXT_PROP: {
2443                 struct usb_ext_prop_desc *d = data;
2444                 u32 type, pdl;
2445                 u16 pnl;
2446
2447                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2448                         return -EINVAL;
2449                 length = le32_to_cpu(d->dwSize);
2450                 if (len < length)
2451                         return -EINVAL;
2452                 type = le32_to_cpu(d->dwPropertyDataType);
2453                 if (type < USB_EXT_PROP_UNICODE ||
2454                     type > USB_EXT_PROP_UNICODE_MULTI) {
2455                         pr_vdebug("unsupported os descriptor property type: %d",
2456                                   type);
2457                         return -EINVAL;
2458                 }
2459                 pnl = le16_to_cpu(d->wPropertyNameLength);
2460                 if (length < 14 + pnl) {
2461                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2462                                   length, pnl, type);
2463                         return -EINVAL;
2464                 }
2465                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2466                 if (length != 14 + pnl + pdl) {
2467                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2468                                   length, pnl, pdl, type);
2469                         return -EINVAL;
2470                 }
2471                 ++ffs->ms_os_descs_ext_prop_count;
2472                 /* property name reported to the host as "WCHAR"s */
2473                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2474                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2475         }
2476                 break;
2477         default:
2478                 pr_vdebug("unknown descriptor: %d\n", type);
2479                 return -EINVAL;
2480         }
2481         return length;
2482 }
2483
2484 static int __ffs_data_got_descs(struct ffs_data *ffs,
2485                                 char *const _data, size_t len)
2486 {
2487         char *data = _data, *raw_descs;
2488         unsigned os_descs_count = 0, counts[3], flags;
2489         int ret = -EINVAL, i;
2490         struct ffs_desc_helper helper;
2491
2492         ENTER();
2493
2494         if (get_unaligned_le32(data + 4) != len)
2495                 goto error;
2496
2497         switch (get_unaligned_le32(data)) {
2498         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2499                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2500                 data += 8;
2501                 len  -= 8;
2502                 break;
2503         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2504                 flags = get_unaligned_le32(data + 8);
2505                 ffs->user_flags = flags;
2506                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2507                               FUNCTIONFS_HAS_HS_DESC |
2508                               FUNCTIONFS_HAS_SS_DESC |
2509                               FUNCTIONFS_HAS_MS_OS_DESC |
2510                               FUNCTIONFS_VIRTUAL_ADDR |
2511                               FUNCTIONFS_EVENTFD |
2512                               FUNCTIONFS_ALL_CTRL_RECIP |
2513                               FUNCTIONFS_CONFIG0_SETUP)) {
2514                         ret = -ENOSYS;
2515                         goto error;
2516                 }
2517                 data += 12;
2518                 len  -= 12;
2519                 break;
2520         default:
2521                 goto error;
2522         }
2523
2524         if (flags & FUNCTIONFS_EVENTFD) {
2525                 if (len < 4)
2526                         goto error;
2527                 ffs->ffs_eventfd =
2528                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2529                 if (IS_ERR(ffs->ffs_eventfd)) {
2530                         ret = PTR_ERR(ffs->ffs_eventfd);
2531                         ffs->ffs_eventfd = NULL;
2532                         goto error;
2533                 }
2534                 data += 4;
2535                 len  -= 4;
2536         }
2537
2538         /* Read fs_count, hs_count and ss_count (if present) */
2539         for (i = 0; i < 3; ++i) {
2540                 if (!(flags & (1 << i))) {
2541                         counts[i] = 0;
2542                 } else if (len < 4) {
2543                         goto error;
2544                 } else {
2545                         counts[i] = get_unaligned_le32(data);
2546                         data += 4;
2547                         len  -= 4;
2548                 }
2549         }
2550         if (flags & (1 << i)) {
2551                 if (len < 4) {
2552                         goto error;
2553                 }
2554                 os_descs_count = get_unaligned_le32(data);
2555                 data += 4;
2556                 len -= 4;
2557         };
2558
2559         /* Read descriptors */
2560         raw_descs = data;
2561         helper.ffs = ffs;
2562         for (i = 0; i < 3; ++i) {
2563                 if (!counts[i])
2564                         continue;
2565                 helper.interfaces_count = 0;
2566                 helper.eps_count = 0;
2567                 ret = ffs_do_descs(counts[i], data, len,
2568                                    __ffs_data_do_entity, &helper);
2569                 if (ret < 0)
2570                         goto error;
2571                 if (!ffs->eps_count && !ffs->interfaces_count) {
2572                         ffs->eps_count = helper.eps_count;
2573                         ffs->interfaces_count = helper.interfaces_count;
2574                 } else {
2575                         if (ffs->eps_count != helper.eps_count) {
2576                                 ret = -EINVAL;
2577                                 goto error;
2578                         }
2579                         if (ffs->interfaces_count != helper.interfaces_count) {
2580                                 ret = -EINVAL;
2581                                 goto error;
2582                         }
2583                 }
2584                 data += ret;
2585                 len  -= ret;
2586         }
2587         if (os_descs_count) {
2588                 ret = ffs_do_os_descs(os_descs_count, data, len,
2589                                       __ffs_data_do_os_desc, ffs);
2590                 if (ret < 0)
2591                         goto error;
2592                 data += ret;
2593                 len -= ret;
2594         }
2595
2596         if (raw_descs == data || len) {
2597                 ret = -EINVAL;
2598                 goto error;
2599         }
2600
2601         ffs->raw_descs_data     = _data;
2602         ffs->raw_descs          = raw_descs;
2603         ffs->raw_descs_length   = data - raw_descs;
2604         ffs->fs_descs_count     = counts[0];
2605         ffs->hs_descs_count     = counts[1];
2606         ffs->ss_descs_count     = counts[2];
2607         ffs->ms_os_descs_count  = os_descs_count;
2608
2609         return 0;
2610
2611 error:
2612         kfree(_data);
2613         return ret;
2614 }
2615
2616 static int __ffs_data_got_strings(struct ffs_data *ffs,
2617                                   char *const _data, size_t len)
2618 {
2619         u32 str_count, needed_count, lang_count;
2620         struct usb_gadget_strings **stringtabs, *t;
2621         const char *data = _data;
2622         struct usb_string *s;
2623
2624         ENTER();
2625
2626         if (unlikely(len < 16 ||
2627                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2628                      get_unaligned_le32(data + 4) != len))
2629                 goto error;
2630         str_count  = get_unaligned_le32(data + 8);
2631         lang_count = get_unaligned_le32(data + 12);
2632
2633         /* if one is zero the other must be zero */
2634         if (unlikely(!str_count != !lang_count))
2635                 goto error;
2636
2637         /* Do we have at least as many strings as descriptors need? */
2638         needed_count = ffs->strings_count;
2639         if (unlikely(str_count < needed_count))
2640                 goto error;
2641
2642         /*
2643          * If we don't need any strings just return and free all
2644          * memory.
2645          */
2646         if (!needed_count) {
2647                 kfree(_data);
2648                 return 0;
2649         }
2650
2651         /* Allocate everything in one chunk so there's less maintenance. */
2652         {
2653                 unsigned i = 0;
2654                 vla_group(d);
2655                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2656                         lang_count + 1);
2657                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2658                 vla_item(d, struct usb_string, strings,
2659                         lang_count*(needed_count+1));
2660
2661                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2662
2663                 if (unlikely(!vlabuf)) {
2664                         kfree(_data);
2665                         return -ENOMEM;
2666                 }
2667
2668                 /* Initialize the VLA pointers */
2669                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2670                 t = vla_ptr(vlabuf, d, stringtab);
2671                 i = lang_count;
2672                 do {
2673                         *stringtabs++ = t++;
2674                 } while (--i);
2675                 *stringtabs = NULL;
2676
2677                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2678                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2679                 t = vla_ptr(vlabuf, d, stringtab);
2680                 s = vla_ptr(vlabuf, d, strings);
2681         }
2682
2683         /* For each language */
2684         data += 16;
2685         len -= 16;
2686
2687         do { /* lang_count > 0 so we can use do-while */
2688                 unsigned needed = needed_count;
2689
2690                 if (unlikely(len < 3))
2691                         goto error_free;
2692                 t->language = get_unaligned_le16(data);
2693                 t->strings  = s;
2694                 ++t;
2695
2696                 data += 2;
2697                 len -= 2;
2698
2699                 /* For each string */
2700                 do { /* str_count > 0 so we can use do-while */
2701                         size_t length = strnlen(data, len);
2702
2703                         if (unlikely(length == len))
2704                                 goto error_free;
2705
2706                         /*
2707                          * User may provide more strings then we need,
2708                          * if that's the case we simply ignore the
2709                          * rest
2710                          */
2711                         if (likely(needed)) {
2712                                 /*
2713                                  * s->id will be set while adding
2714                                  * function to configuration so for
2715                                  * now just leave garbage here.
2716                                  */
2717                                 s->s = data;
2718                                 --needed;
2719                                 ++s;
2720                         }
2721
2722                         data += length + 1;
2723                         len -= length + 1;
2724                 } while (--str_count);
2725
2726                 s->id = 0;   /* terminator */
2727                 s->s = NULL;
2728                 ++s;
2729
2730         } while (--lang_count);
2731
2732         /* Some garbage left? */
2733         if (unlikely(len))
2734                 goto error_free;
2735
2736         /* Done! */
2737         ffs->stringtabs = stringtabs;
2738         ffs->raw_strings = _data;
2739
2740         return 0;
2741
2742 error_free:
2743         kfree(stringtabs);
2744 error:
2745         kfree(_data);
2746         return -EINVAL;
2747 }
2748
2749
2750 /* Events handling and management *******************************************/
2751
2752 static void __ffs_event_add(struct ffs_data *ffs,
2753                             enum usb_functionfs_event_type type)
2754 {
2755         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2756         int neg = 0;
2757
2758         /*
2759          * Abort any unhandled setup
2760          *
2761          * We do not need to worry about some cmpxchg() changing value
2762          * of ffs->setup_state without holding the lock because when
2763          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2764          * the source does nothing.
2765          */
2766         if (ffs->setup_state == FFS_SETUP_PENDING)
2767                 ffs->setup_state = FFS_SETUP_CANCELLED;
2768
2769         /*
2770          * Logic of this function guarantees that there are at most four pending
2771          * evens on ffs->ev.types queue.  This is important because the queue
2772          * has space for four elements only and __ffs_ep0_read_events function
2773          * depends on that limit as well.  If more event types are added, those
2774          * limits have to be revisited or guaranteed to still hold.
2775          */
2776         switch (type) {
2777         case FUNCTIONFS_RESUME:
2778                 rem_type2 = FUNCTIONFS_SUSPEND;
2779                 /* FALL THROUGH */
2780         case FUNCTIONFS_SUSPEND:
2781         case FUNCTIONFS_SETUP:
2782                 rem_type1 = type;
2783                 /* Discard all similar events */
2784                 break;
2785
2786         case FUNCTIONFS_BIND:
2787         case FUNCTIONFS_UNBIND:
2788         case FUNCTIONFS_DISABLE:
2789         case FUNCTIONFS_ENABLE:
2790                 /* Discard everything other then power management. */
2791                 rem_type1 = FUNCTIONFS_SUSPEND;
2792                 rem_type2 = FUNCTIONFS_RESUME;
2793                 neg = 1;
2794                 break;
2795
2796         default:
2797                 WARN(1, "%d: unknown event, this should not happen\n", type);
2798                 return;
2799         }
2800
2801         {
2802                 u8 *ev  = ffs->ev.types, *out = ev;
2803                 unsigned n = ffs->ev.count;
2804                 for (; n; --n, ++ev)
2805                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2806                                 *out++ = *ev;
2807                         else
2808                                 pr_vdebug("purging event %d\n", *ev);
2809                 ffs->ev.count = out - ffs->ev.types;
2810         }
2811
2812         pr_vdebug("adding event %d\n", type);
2813         ffs->ev.types[ffs->ev.count++] = type;
2814         wake_up_locked(&ffs->ev.waitq);
2815         if (ffs->ffs_eventfd)
2816                 eventfd_signal(ffs->ffs_eventfd, 1);
2817 }
2818
2819 static void ffs_event_add(struct ffs_data *ffs,
2820                           enum usb_functionfs_event_type type)
2821 {
2822         unsigned long flags;
2823         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2824         __ffs_event_add(ffs, type);
2825         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2826 }
2827
2828 /* Bind/unbind USB function hooks *******************************************/
2829
2830 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2831 {
2832         int i;
2833
2834         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2835                 if (ffs->eps_addrmap[i] == endpoint_address)
2836                         return i;
2837         return -ENOENT;
2838 }
2839
2840 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2841                                     struct usb_descriptor_header *desc,
2842                                     void *priv)
2843 {
2844         struct usb_endpoint_descriptor *ds = (void *)desc;
2845         struct ffs_function *func = priv;
2846         struct ffs_ep *ffs_ep;
2847         unsigned ep_desc_id;
2848         int idx;
2849         static const char *speed_names[] = { "full", "high", "super" };
2850
2851         if (type != FFS_DESCRIPTOR)
2852                 return 0;
2853
2854         /*
2855          * If ss_descriptors is not NULL, we are reading super speed
2856          * descriptors; if hs_descriptors is not NULL, we are reading high
2857          * speed descriptors; otherwise, we are reading full speed
2858          * descriptors.
2859          */
2860         if (func->function.ss_descriptors) {
2861                 ep_desc_id = 2;
2862                 func->function.ss_descriptors[(long)valuep] = desc;
2863         } else if (func->function.hs_descriptors) {
2864                 ep_desc_id = 1;
2865                 func->function.hs_descriptors[(long)valuep] = desc;
2866         } else {
2867                 ep_desc_id = 0;
2868                 func->function.fs_descriptors[(long)valuep]    = desc;
2869         }
2870
2871         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2872                 return 0;
2873
2874         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2875         if (idx < 0)
2876                 return idx;
2877
2878         ffs_ep = func->eps + idx;
2879
2880         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2881                 pr_err("two %sspeed descriptors for EP %d\n",
2882                           speed_names[ep_desc_id],
2883                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2884                 return -EINVAL;
2885         }
2886         ffs_ep->descs[ep_desc_id] = ds;
2887
2888         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2889         if (ffs_ep->ep) {
2890                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2891                 if (!ds->wMaxPacketSize)
2892                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2893         } else {
2894                 struct usb_request *req;
2895                 struct usb_ep *ep;
2896                 u8 bEndpointAddress;
2897                 u16 wMaxPacketSize;
2898
2899                 /*
2900                  * We back up bEndpointAddress because autoconfig overwrites
2901                  * it with physical endpoint address.
2902                  */
2903                 bEndpointAddress = ds->bEndpointAddress;
2904                 /*
2905                  * We back up wMaxPacketSize because autoconfig treats
2906                  * endpoint descriptors as if they were full speed.
2907                  */
2908                 wMaxPacketSize = ds->wMaxPacketSize;
2909                 pr_vdebug("autoconfig\n");
2910                 ep = usb_ep_autoconfig(func->gadget, ds);
2911                 if (unlikely(!ep))
2912                         return -ENOTSUPP;
2913                 ep->driver_data = func->eps + idx;
2914
2915                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2916                 if (unlikely(!req))
2917                         return -ENOMEM;
2918
2919                 ffs_ep->ep  = ep;
2920                 ffs_ep->req = req;
2921                 func->eps_revmap[ds->bEndpointAddress &
2922                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2923                 /*
2924                  * If we use virtual address mapping, we restore
2925                  * original bEndpointAddress value.
2926                  */
2927                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2928                         ds->bEndpointAddress = bEndpointAddress;
2929                 /*
2930                  * Restore wMaxPacketSize which was potentially
2931                  * overwritten by autoconfig.
2932                  */
2933                 ds->wMaxPacketSize = wMaxPacketSize;
2934         }
2935         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2936
2937         return 0;
2938 }
2939
2940 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2941                                    struct usb_descriptor_header *desc,
2942                                    void *priv)
2943 {
2944         struct ffs_function *func = priv;
2945         unsigned idx;
2946         u8 newValue;
2947
2948         switch (type) {
2949         default:
2950         case FFS_DESCRIPTOR:
2951                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2952                 return 0;
2953
2954         case FFS_INTERFACE:
2955                 idx = *valuep;
2956                 if (func->interfaces_nums[idx] < 0) {
2957                         int id = usb_interface_id(func->conf, &func->function);
2958                         if (unlikely(id < 0))
2959                                 return id;
2960                         func->interfaces_nums[idx] = id;
2961                 }
2962                 newValue = func->interfaces_nums[idx];
2963                 break;
2964
2965         case FFS_STRING:
2966                 /* String' IDs are allocated when fsf_data is bound to cdev */
2967                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2968                 break;
2969
2970         case FFS_ENDPOINT:
2971                 /*
2972                  * USB_DT_ENDPOINT are handled in
2973                  * __ffs_func_bind_do_descs().
2974                  */
2975                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2976                         return 0;
2977
2978                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2979                 if (unlikely(!func->eps[idx].ep))
2980                         return -EINVAL;
2981
2982                 {
2983                         struct usb_endpoint_descriptor **descs;
2984                         descs = func->eps[idx].descs;
2985                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2986                 }
2987                 break;
2988         }
2989
2990         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2991         *valuep = newValue;
2992         return 0;
2993 }
2994
2995 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2996                                       struct usb_os_desc_header *h, void *data,
2997                                       unsigned len, void *priv)
2998 {
2999         struct ffs_function *func = priv;
3000         u8 length = 0;
3001
3002         switch (type) {
3003         case FFS_OS_DESC_EXT_COMPAT: {
3004                 struct usb_ext_compat_desc *desc = data;
3005                 struct usb_os_desc_table *t;
3006
3007                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
3008                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
3009                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
3010                        ARRAY_SIZE(desc->CompatibleID) +
3011                        ARRAY_SIZE(desc->SubCompatibleID));
3012                 length = sizeof(*desc);
3013         }
3014                 break;
3015         case FFS_OS_DESC_EXT_PROP: {
3016                 struct usb_ext_prop_desc *desc = data;
3017                 struct usb_os_desc_table *t;
3018                 struct usb_os_desc_ext_prop *ext_prop;
3019                 char *ext_prop_name;
3020                 char *ext_prop_data;
3021
3022                 t = &func->function.os_desc_table[h->interface];
3023                 t->if_id = func->interfaces_nums[h->interface];
3024
3025                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
3026                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
3027
3028                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
3029                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
3030                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
3031                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
3032                 length = ext_prop->name_len + ext_prop->data_len + 14;
3033
3034                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
3035                 func->ffs->ms_os_descs_ext_prop_name_avail +=
3036                         ext_prop->name_len;
3037
3038                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
3039                 func->ffs->ms_os_descs_ext_prop_data_avail +=
3040                         ext_prop->data_len;
3041                 memcpy(ext_prop_data,
3042                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
3043                        ext_prop->data_len);
3044                 /* unicode data reported to the host as "WCHAR"s */
3045                 switch (ext_prop->type) {
3046                 case USB_EXT_PROP_UNICODE:
3047                 case USB_EXT_PROP_UNICODE_ENV:
3048                 case USB_EXT_PROP_UNICODE_LINK:
3049                 case USB_EXT_PROP_UNICODE_MULTI:
3050                         ext_prop->data_len *= 2;
3051                         break;
3052                 }
3053                 ext_prop->data = ext_prop_data;
3054
3055                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3056                        ext_prop->name_len);
3057                 /* property name reported to the host as "WCHAR"s */
3058                 ext_prop->name_len *= 2;
3059                 ext_prop->name = ext_prop_name;
3060
3061                 t->os_desc->ext_prop_len +=
3062                         ext_prop->name_len + ext_prop->data_len + 14;
3063                 ++t->os_desc->ext_prop_count;
3064                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3065         }
3066                 break;
3067         default:
3068                 pr_vdebug("unknown descriptor: %d\n", type);
3069         }
3070
3071         return length;
3072 }
3073
3074 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3075                                                 struct usb_configuration *c)
3076 {
3077         struct ffs_function *func = ffs_func_from_usb(f);
3078         struct f_fs_opts *ffs_opts =
3079                 container_of(f->fi, struct f_fs_opts, func_inst);
3080         int ret;
3081
3082         ENTER();
3083
3084         /*
3085          * Legacy gadget triggers binding in functionfs_ready_callback,
3086          * which already uses locking; taking the same lock here would
3087          * cause a deadlock.
3088          *
3089          * Configfs-enabled gadgets however do need ffs_dev_lock.
3090          */
3091         if (!ffs_opts->no_configfs)
3092                 ffs_dev_lock();
3093         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3094         func->ffs = ffs_opts->dev->ffs_data;
3095         if (!ffs_opts->no_configfs)
3096                 ffs_dev_unlock();
3097         if (ret)
3098                 return ERR_PTR(ret);
3099
3100         func->conf = c;
3101         func->gadget = c->cdev->gadget;
3102
3103         /*
3104          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3105          * configurations are bound in sequence with list_for_each_entry,
3106          * in each configuration its functions are bound in sequence
3107          * with list_for_each_entry, so we assume no race condition
3108          * with regard to ffs_opts->bound access
3109          */
3110         if (!ffs_opts->refcnt) {
3111                 ret = functionfs_bind(func->ffs, c->cdev);
3112                 if (ret)
3113                         return ERR_PTR(ret);
3114         }
3115         ffs_opts->refcnt++;
3116         func->function.strings = func->ffs->stringtabs;
3117
3118         return ffs_opts;
3119 }
3120
3121 static int _ffs_func_bind(struct usb_configuration *c,
3122                           struct usb_function *f)
3123 {
3124         struct ffs_function *func = ffs_func_from_usb(f);
3125         struct ffs_data *ffs = func->ffs;
3126
3127         const int full = !!func->ffs->fs_descs_count;
3128         const int high = !!func->ffs->hs_descs_count;
3129         const int super = !!func->ffs->ss_descs_count;
3130
3131         int fs_len, hs_len, ss_len, ret, i;
3132         struct ffs_ep *eps_ptr;
3133
3134         /* Make it a single chunk, less management later on */
3135         vla_group(d);
3136         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3137         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3138                 full ? ffs->fs_descs_count + 1 : 0);
3139         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3140                 high ? ffs->hs_descs_count + 1 : 0);
3141         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3142                 super ? ffs->ss_descs_count + 1 : 0);
3143         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3144         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3145                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3146         vla_item_with_sz(d, char[16], ext_compat,
3147                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3148         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3149                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3150         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3151                          ffs->ms_os_descs_ext_prop_count);
3152         vla_item_with_sz(d, char, ext_prop_name,
3153                          ffs->ms_os_descs_ext_prop_name_len);
3154         vla_item_with_sz(d, char, ext_prop_data,
3155                          ffs->ms_os_descs_ext_prop_data_len);
3156         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3157         char *vlabuf;
3158
3159         ENTER();
3160
3161         /* Has descriptors only for speeds gadget does not support */
3162         if (unlikely(!(full | high | super)))
3163                 return -ENOTSUPP;
3164
3165         /* Allocate a single chunk, less management later on */
3166         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3167         if (unlikely(!vlabuf))
3168                 return -ENOMEM;
3169
3170         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3171         ffs->ms_os_descs_ext_prop_name_avail =
3172                 vla_ptr(vlabuf, d, ext_prop_name);
3173         ffs->ms_os_descs_ext_prop_data_avail =
3174                 vla_ptr(vlabuf, d, ext_prop_data);
3175
3176         /* Copy descriptors  */
3177         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3178                ffs->raw_descs_length);
3179
3180         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3181         eps_ptr = vla_ptr(vlabuf, d, eps);
3182         for (i = 0; i < ffs->eps_count; i++)
3183                 eps_ptr[i].num = -1;
3184
3185         /* Save pointers
3186          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3187         */
3188         func->eps             = vla_ptr(vlabuf, d, eps);
3189         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3190
3191         /*
3192          * Go through all the endpoint descriptors and allocate
3193          * endpoints first, so that later we can rewrite the endpoint
3194          * numbers without worrying that it may be described later on.
3195          */
3196         if (likely(full)) {
3197                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3198                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3199                                       vla_ptr(vlabuf, d, raw_descs),
3200                                       d_raw_descs__sz,
3201                                       __ffs_func_bind_do_descs, func);
3202                 if (unlikely(fs_len < 0)) {
3203                         ret = fs_len;
3204                         goto error;
3205                 }
3206         } else {
3207                 fs_len = 0;
3208         }
3209
3210         if (likely(high)) {
3211                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3212                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3213                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3214                                       d_raw_descs__sz - fs_len,
3215                                       __ffs_func_bind_do_descs, func);
3216                 if (unlikely(hs_len < 0)) {
3217                         ret = hs_len;
3218                         goto error;
3219                 }
3220         } else {
3221                 hs_len = 0;
3222         }
3223
3224         if (likely(super)) {
3225                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3226                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3227                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3228                                 d_raw_descs__sz - fs_len - hs_len,
3229                                 __ffs_func_bind_do_descs, func);
3230                 if (unlikely(ss_len < 0)) {
3231                         ret = ss_len;
3232                         goto error;
3233                 }
3234         } else {
3235                 ss_len = 0;
3236         }
3237
3238         /*
3239          * Now handle interface numbers allocation and interface and
3240          * endpoint numbers rewriting.  We can do that in one go
3241          * now.
3242          */
3243         ret = ffs_do_descs(ffs->fs_descs_count +
3244                            (high ? ffs->hs_descs_count : 0) +
3245                            (super ? ffs->ss_descs_count : 0),
3246                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3247                            __ffs_func_bind_do_nums, func);
3248         if (unlikely(ret < 0))
3249                 goto error;
3250
3251         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3252         if (c->cdev->use_os_string) {
3253                 for (i = 0; i < ffs->interfaces_count; ++i) {
3254                         struct usb_os_desc *desc;
3255
3256                         desc = func->function.os_desc_table[i].os_desc =
3257                                 vla_ptr(vlabuf, d, os_desc) +
3258                                 i * sizeof(struct usb_os_desc);
3259                         desc->ext_compat_id =
3260                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3261                         INIT_LIST_HEAD(&desc->ext_prop);
3262                 }
3263                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3264                                       vla_ptr(vlabuf, d, raw_descs) +
3265                                       fs_len + hs_len + ss_len,
3266                                       d_raw_descs__sz - fs_len - hs_len -
3267                                       ss_len,
3268                                       __ffs_func_bind_do_os_desc, func);
3269                 if (unlikely(ret < 0))
3270                         goto error;
3271         }
3272         func->function.os_desc_n =
3273                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3274
3275         /* And we're done */
3276         ffs_event_add(ffs, FUNCTIONFS_BIND);
3277         return 0;
3278
3279 error:
3280         /* XXX Do we need to release all claimed endpoints here? */
3281         return ret;
3282 }
3283
3284 static int ffs_func_bind(struct usb_configuration *c,
3285                          struct usb_function *f)
3286 {
3287         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3288         struct ffs_function *func = ffs_func_from_usb(f);
3289         int ret;
3290
3291         if (IS_ERR(ffs_opts))
3292                 return PTR_ERR(ffs_opts);
3293
3294         ret = _ffs_func_bind(c, f);
3295         if (ret && !--ffs_opts->refcnt)
3296                 functionfs_unbind(func->ffs);
3297
3298         return ret;
3299 }
3300
3301
3302 /* Other USB function hooks *************************************************/
3303
3304 static void ffs_reset_work(struct work_struct *work)
3305 {
3306         struct ffs_data *ffs = container_of(work,
3307                 struct ffs_data, reset_work);
3308         ffs_data_reset(ffs);
3309 }
3310
3311 static int ffs_func_set_alt(struct usb_function *f,
3312                             unsigned interface, unsigned alt)
3313 {
3314         struct ffs_function *func = ffs_func_from_usb(f);
3315         struct ffs_data *ffs = func->ffs;
3316         int ret = 0, intf;
3317
3318         if (alt != (unsigned)-1) {
3319                 intf = ffs_func_revmap_intf(func, interface);
3320                 if (unlikely(intf < 0))
3321                         return intf;
3322         }
3323
3324         if (ffs->func)
3325                 ffs_func_eps_disable(ffs->func);
3326
3327         if (ffs->state == FFS_DEACTIVATED) {
3328                 ffs->state = FFS_CLOSING;
3329                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3330                 schedule_work(&ffs->reset_work);
3331                 return -ENODEV;
3332         }
3333
3334         if (ffs->state != FFS_ACTIVE)
3335                 return -ENODEV;
3336
3337         if (alt == (unsigned)-1) {
3338                 ffs->func = NULL;
3339                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3340                 return 0;
3341         }
3342
3343         ffs->func = func;
3344         ret = ffs_func_eps_enable(func);
3345         if (likely(ret >= 0))
3346                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3347         return ret;
3348 }
3349
3350 static void ffs_func_disable(struct usb_function *f)
3351 {
3352         ffs_func_set_alt(f, 0, (unsigned)-1);
3353 }
3354
3355 static int ffs_func_setup(struct usb_function *f,
3356                           const struct usb_ctrlrequest *creq)
3357 {
3358         struct ffs_function *func = ffs_func_from_usb(f);
3359         struct ffs_data *ffs = func->ffs;
3360         unsigned long flags;
3361         int ret;
3362
3363         ENTER();
3364
3365         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3366         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3367         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3368         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3369         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3370
3371         /*
3372          * Most requests directed to interface go through here
3373          * (notable exceptions are set/get interface) so we need to
3374          * handle them.  All other either handled by composite or
3375          * passed to usb_configuration->setup() (if one is set).  No
3376          * matter, we will handle requests directed to endpoint here
3377          * as well (as it's straightforward).  Other request recipient
3378          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3379          * is being used.
3380          */
3381         if (ffs->state != FFS_ACTIVE)
3382                 return -ENODEV;
3383
3384         switch (creq->bRequestType & USB_RECIP_MASK) {
3385         case USB_RECIP_INTERFACE:
3386                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3387                 if (unlikely(ret < 0))
3388                         return ret;
3389                 break;
3390
3391         case USB_RECIP_ENDPOINT:
3392                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3393                 if (unlikely(ret < 0))
3394                         return ret;
3395                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3396                         ret = func->ffs->eps_addrmap[ret];
3397                 break;
3398
3399         default:
3400                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3401                         ret = le16_to_cpu(creq->wIndex);
3402                 else
3403                         return -EOPNOTSUPP;
3404         }
3405
3406         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3407         ffs->ev.setup = *creq;
3408         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3409         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3410         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3411
3412         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3413 }
3414
3415 static bool ffs_func_req_match(struct usb_function *f,
3416                                const struct usb_ctrlrequest *creq,
3417                                bool config0)
3418 {
3419         struct ffs_function *func = ffs_func_from_usb(f);
3420
3421         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3422                 return false;
3423
3424         switch (creq->bRequestType & USB_RECIP_MASK) {
3425         case USB_RECIP_INTERFACE:
3426                 return (ffs_func_revmap_intf(func,
3427                                              le16_to_cpu(creq->wIndex)) >= 0);
3428         case USB_RECIP_ENDPOINT:
3429                 return (ffs_func_revmap_ep(func,
3430                                            le16_to_cpu(creq->wIndex)) >= 0);
3431         default:
3432                 return (bool) (func->ffs->user_flags &
3433                                FUNCTIONFS_ALL_CTRL_RECIP);
3434         }
3435 }
3436
3437 static void ffs_func_suspend(struct usb_function *f)
3438 {
3439         ENTER();
3440         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3441 }
3442
3443 static void ffs_func_resume(struct usb_function *f)
3444 {
3445         ENTER();
3446         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3447 }
3448
3449
3450 /* Endpoint and interface numbers reverse mapping ***************************/
3451
3452 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3453 {
3454         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3455         return num ? num : -EDOM;
3456 }
3457
3458 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3459 {
3460         short *nums = func->interfaces_nums;
3461         unsigned count = func->ffs->interfaces_count;
3462
3463         for (; count; --count, ++nums) {
3464                 if (*nums >= 0 && *nums == intf)
3465                         return nums - func->interfaces_nums;
3466         }
3467
3468         return -EDOM;
3469 }
3470
3471
3472 /* Devices management *******************************************************/
3473
3474 static LIST_HEAD(ffs_devices);
3475
3476 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3477 {
3478         struct ffs_dev *dev;
3479
3480         if (!name)
3481                 return NULL;
3482
3483         list_for_each_entry(dev, &ffs_devices, entry) {
3484                 if (strcmp(dev->name, name) == 0)
3485                         return dev;
3486         }
3487
3488         return NULL;
3489 }
3490
3491 /*
3492  * ffs_lock must be taken by the caller of this function
3493  */
3494 static struct ffs_dev *_ffs_get_single_dev(void)
3495 {
3496         struct ffs_dev *dev;
3497
3498         if (list_is_singular(&ffs_devices)) {
3499                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3500                 if (dev->single)
3501                         return dev;
3502         }
3503
3504         return NULL;
3505 }
3506
3507 /*
3508  * ffs_lock must be taken by the caller of this function
3509  */
3510 static struct ffs_dev *_ffs_find_dev(const char *name)
3511 {
3512         struct ffs_dev *dev;
3513
3514         dev = _ffs_get_single_dev();
3515         if (dev)
3516                 return dev;
3517
3518         return _ffs_do_find_dev(name);
3519 }
3520
3521 /* Configfs support *********************************************************/
3522
3523 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3524 {
3525         return container_of(to_config_group(item), struct f_fs_opts,
3526                             func_inst.group);
3527 }
3528
3529 static void ffs_attr_release(struct config_item *item)
3530 {
3531         struct f_fs_opts *opts = to_ffs_opts(item);
3532
3533         usb_put_function_instance(&opts->func_inst);
3534 }
3535
3536 static struct configfs_item_operations ffs_item_ops = {
3537         .release        = ffs_attr_release,
3538 };
3539
3540 static const struct config_item_type ffs_func_type = {
3541         .ct_item_ops    = &ffs_item_ops,
3542         .ct_owner       = THIS_MODULE,
3543 };
3544
3545
3546 /* Function registration interface ******************************************/
3547
3548 static void ffs_free_inst(struct usb_function_instance *f)
3549 {
3550         struct f_fs_opts *opts;
3551
3552         opts = to_f_fs_opts(f);
3553         ffs_dev_lock();
3554         _ffs_free_dev(opts->dev);
3555         ffs_dev_unlock();
3556         kfree(opts);
3557 }
3558
3559 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3560 {
3561         if (strlen(name) >= FIELD_SIZEOF(struct ffs_dev, name))
3562                 return -ENAMETOOLONG;
3563         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3564 }
3565
3566 static struct usb_function_instance *ffs_alloc_inst(void)
3567 {
3568         struct f_fs_opts *opts;
3569         struct ffs_dev *dev;
3570
3571         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3572         if (!opts)
3573                 return ERR_PTR(-ENOMEM);
3574
3575         opts->func_inst.set_inst_name = ffs_set_inst_name;
3576         opts->func_inst.free_func_inst = ffs_free_inst;
3577         ffs_dev_lock();
3578         dev = _ffs_alloc_dev();
3579         ffs_dev_unlock();
3580         if (IS_ERR(dev)) {
3581                 kfree(opts);
3582                 return ERR_CAST(dev);
3583         }
3584         opts->dev = dev;
3585         dev->opts = opts;
3586
3587         config_group_init_type_name(&opts->func_inst.group, "",
3588                                     &ffs_func_type);
3589         return &opts->func_inst;
3590 }
3591
3592 static void ffs_free(struct usb_function *f)
3593 {
3594         kfree(ffs_func_from_usb(f));
3595 }
3596
3597 static void ffs_func_unbind(struct usb_configuration *c,
3598                             struct usb_function *f)
3599 {
3600         struct ffs_function *func = ffs_func_from_usb(f);
3601         struct ffs_data *ffs = func->ffs;
3602         struct f_fs_opts *opts =
3603                 container_of(f->fi, struct f_fs_opts, func_inst);
3604         struct ffs_ep *ep = func->eps;
3605         unsigned count = ffs->eps_count;
3606         unsigned long flags;
3607
3608         ENTER();
3609         if (ffs->func == func) {
3610                 ffs_func_eps_disable(func);
3611                 ffs->func = NULL;
3612         }
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->interfaces_nums = NULL;
3636
3637         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3638 }
3639
3640 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3641 {
3642         struct ffs_function *func;
3643
3644         ENTER();
3645
3646         func = kzalloc(sizeof(*func), GFP_KERNEL);
3647         if (unlikely(!func))
3648                 return ERR_PTR(-ENOMEM);
3649
3650         func->function.name    = "Function FS Gadget";
3651
3652         func->function.bind    = ffs_func_bind;
3653         func->function.unbind  = ffs_func_unbind;
3654         func->function.set_alt = ffs_func_set_alt;
3655         func->function.disable = ffs_func_disable;
3656         func->function.setup   = ffs_func_setup;
3657         func->function.req_match = ffs_func_req_match;
3658         func->function.suspend = ffs_func_suspend;
3659         func->function.resume  = ffs_func_resume;
3660         func->function.free_func = ffs_free;
3661
3662         return &func->function;
3663 }
3664
3665 /*
3666  * ffs_lock must be taken by the caller of this function
3667  */
3668 static struct ffs_dev *_ffs_alloc_dev(void)
3669 {
3670         struct ffs_dev *dev;
3671         int ret;
3672
3673         if (_ffs_get_single_dev())
3674                         return ERR_PTR(-EBUSY);
3675
3676         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3677         if (!dev)
3678                 return ERR_PTR(-ENOMEM);
3679
3680         if (list_empty(&ffs_devices)) {
3681                 ret = functionfs_init();
3682                 if (ret) {
3683                         kfree(dev);
3684                         return ERR_PTR(ret);
3685                 }
3686         }
3687
3688         list_add(&dev->entry, &ffs_devices);
3689
3690         return dev;
3691 }
3692
3693 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3694 {
3695         struct ffs_dev *existing;
3696         int ret = 0;
3697
3698         ffs_dev_lock();
3699
3700         existing = _ffs_do_find_dev(name);
3701         if (!existing)
3702                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3703         else if (existing != dev)
3704                 ret = -EBUSY;
3705
3706         ffs_dev_unlock();
3707
3708         return ret;
3709 }
3710 EXPORT_SYMBOL_GPL(ffs_name_dev);
3711
3712 int ffs_single_dev(struct ffs_dev *dev)
3713 {
3714         int ret;
3715
3716         ret = 0;
3717         ffs_dev_lock();
3718
3719         if (!list_is_singular(&ffs_devices))
3720                 ret = -EBUSY;
3721         else
3722                 dev->single = true;
3723
3724         ffs_dev_unlock();
3725         return ret;
3726 }
3727 EXPORT_SYMBOL_GPL(ffs_single_dev);
3728
3729 /*
3730  * ffs_lock must be taken by the caller of this function
3731  */
3732 static void _ffs_free_dev(struct ffs_dev *dev)
3733 {
3734         list_del(&dev->entry);
3735
3736         /* Clear the private_data pointer to stop incorrect dev access */
3737         if (dev->ffs_data)
3738                 dev->ffs_data->private_data = NULL;
3739
3740         kfree(dev);
3741         if (list_empty(&ffs_devices))
3742                 functionfs_cleanup();
3743 }
3744
3745 static void *ffs_acquire_dev(const char *dev_name)
3746 {
3747         struct ffs_dev *ffs_dev;
3748
3749         ENTER();
3750         ffs_dev_lock();
3751
3752         ffs_dev = _ffs_find_dev(dev_name);
3753         if (!ffs_dev)
3754                 ffs_dev = ERR_PTR(-ENOENT);
3755         else if (ffs_dev->mounted)
3756                 ffs_dev = ERR_PTR(-EBUSY);
3757         else if (ffs_dev->ffs_acquire_dev_callback &&
3758             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3759                 ffs_dev = ERR_PTR(-ENOENT);
3760         else
3761                 ffs_dev->mounted = true;
3762
3763         ffs_dev_unlock();
3764         return ffs_dev;
3765 }
3766
3767 static void ffs_release_dev(struct ffs_data *ffs_data)
3768 {
3769         struct ffs_dev *ffs_dev;
3770
3771         ENTER();
3772         ffs_dev_lock();
3773
3774         ffs_dev = ffs_data->private_data;
3775         if (ffs_dev) {
3776                 ffs_dev->mounted = false;
3777
3778                 if (ffs_dev->ffs_release_dev_callback)
3779                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3780         }
3781
3782         ffs_dev_unlock();
3783 }
3784
3785 static int ffs_ready(struct ffs_data *ffs)
3786 {
3787         struct ffs_dev *ffs_obj;
3788         int ret = 0;
3789
3790         ENTER();
3791         ffs_dev_lock();
3792
3793         ffs_obj = ffs->private_data;
3794         if (!ffs_obj) {
3795                 ret = -EINVAL;
3796                 goto done;
3797         }
3798         if (WARN_ON(ffs_obj->desc_ready)) {
3799                 ret = -EBUSY;
3800                 goto done;
3801         }
3802
3803         ffs_obj->desc_ready = true;
3804         ffs_obj->ffs_data = ffs;
3805
3806         if (ffs_obj->ffs_ready_callback) {
3807                 ret = ffs_obj->ffs_ready_callback(ffs);
3808                 if (ret)
3809                         goto done;
3810         }
3811
3812         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3813 done:
3814         ffs_dev_unlock();
3815         return ret;
3816 }
3817
3818 static void ffs_closed(struct ffs_data *ffs)
3819 {
3820         struct ffs_dev *ffs_obj;
3821         struct f_fs_opts *opts;
3822         struct config_item *ci;
3823
3824         ENTER();
3825         ffs_dev_lock();
3826
3827         ffs_obj = ffs->private_data;
3828         if (!ffs_obj)
3829                 goto done;
3830
3831         ffs_obj->desc_ready = false;
3832         ffs_obj->ffs_data = NULL;
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                 ? likely(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 (unlikely(!len))
3871                 return NULL;
3872
3873         data = kmalloc(len, GFP_KERNEL);
3874         if (unlikely(!data))
3875                 return ERR_PTR(-ENOMEM);
3876
3877         if (unlikely(copy_from_user(data, buf, len))) {
3878                 kfree(data);
3879                 return ERR_PTR(-EFAULT);
3880         }
3881
3882         pr_vdebug("Buffer from user space:\n");
3883         ffs_dump_mem("", data, len);
3884
3885         return data;
3886 }
3887
3888 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3889 MODULE_LICENSE("GPL");
3890 MODULE_AUTHOR("Michal Nazarewicz");