drivers/usb/gadget/function/f_fs.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_fs.c -- user mode file system API for USB composite function controllers
   4  *
   5  * Copyright (C) 2010 Samsung Electronics
   6  * Author: Michal Nazarewicz <mina86@mina86.com>
   7  *
   8  * Based on inode.c (GadgetFS) which was:
   9  * Copyright (C) 2003-2004 David Brownell
  10  * Copyright (C) 2003 Agilent Technologies
  11  */
  12
  13
  14 /* #define DEBUG */
  15 /* #define VERBOSE_DEBUG */
  16
  17 #include <linux/blkdev.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/export.h>
  20 #include <linux/fs_parser.h>
  21 #include <linux/hid.h>
  22 #include <linux/mm.h>
  23 #include <linux/module.h>
  24 #include <linux/scatterlist.h>
  25 #include <linux/sched/signal.h>
  26 #include <linux/uio.h>
  27 #include <linux/vmalloc.h>
  28 #include <asm/unaligned.h>
  29
  30 #include <linux/usb/ccid.h>
  31 #include <linux/usb/composite.h>
  32 #include <linux/usb/functionfs.h>
  33
  34 #include <linux/aio.h>
  35 #include <linux/kthread.h>
  36 #include <linux/poll.h>
  37 #include <linux/eventfd.h>
  38
  39 #include "u_fs.h"
  40 #include "u_f.h"
  41 #include "u_os_desc.h"
  42 #include "configfs.h"
  43
  44 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  45
  46 /* Reference counter handling */
  47 static void ffs_data_get(struct ffs_data *ffs);
  48 static void ffs_data_put(struct ffs_data *ffs);
  49 /* Creates new ffs_data object. */
  50 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  51         __attribute__((malloc));
  52
  53 /* Opened counter handling. */
  54 static void ffs_data_opened(struct ffs_data *ffs);
  55 static void ffs_data_closed(struct ffs_data *ffs);
  56
  57 /* Called with ffs->mutex held; take over ownership of data. */
  58 static int __must_check
  59 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  60 static int __must_check
  61 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  62
  63
  64 /* The function structure ***************************************************/
  65
  66 struct ffs_ep;
  67
  68 struct ffs_function {
  69         struct usb_configuration        *conf;
  70         struct usb_gadget               *gadget;
  71         struct ffs_data                 *ffs;
  72
  73         struct ffs_ep                   *eps;
  74         u8                              eps_revmap[16];
  75         short                           *interfaces_nums;
  76
  77         struct usb_function             function;
  78 };
  79
  80
  81 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  82 {
  83         return container_of(f, struct ffs_function, function);
  84 }
  85
  86
  87 static inline enum ffs_setup_state
  88 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  89 {
  90         return (enum ffs_setup_state)
  91                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  92 }
  93
  94
  95 static void ffs_func_eps_disable(struct ffs_function *func);
  96 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  97
  98 static int ffs_func_bind(struct usb_configuration *,
  99                          struct usb_function *);
 100 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 101 static void ffs_func_disable(struct usb_function *);
 102 static int ffs_func_setup(struct usb_function *,
 103                           const struct usb_ctrlrequest *);
 104 static bool ffs_func_req_match(struct usb_function *,
 105                                const struct usb_ctrlrequest *,
 106                                bool config0);
 107 static void ffs_func_suspend(struct usb_function *);
 108 static void ffs_func_resume(struct usb_function *);
 109
 110
 111 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 112 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 113
 114
 115 /* The endpoints structures *************************************************/
 116
 117 struct ffs_ep {
 118         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 119         struct usb_request              *req;   /* P: epfile->mutex */
 120
 121         /* [0]: full speed, [1]: high speed, [2]: super speed */
 122         struct usb_endpoint_descriptor  *descs[3];
 123
 124         u8                              num;
 125 };
 126
 127 struct ffs_epfile {
 128         /* Protects ep->ep and ep->req. */
 129         struct mutex                    mutex;
 130
 131         struct ffs_data                 *ffs;
 132         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 133
 134         struct dentry                   *dentry;
 135
 136         /*
 137          * Buffer for holding data from partial reads which may happen since
 138          * we’re rounding user read requests to a multiple of a max packet size.
 139          *
 140          * The pointer is initialised with NULL value and may be set by
 141          * __ffs_epfile_read_data function to point to a temporary buffer.
 142          *
 143          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 144          * data from said buffer and eventually free it.  Importantly, while the
 145          * function is using the buffer, it sets the pointer to NULL.  This is
 146          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 147          * can never run concurrently (they are synchronised by epfile->mutex)
 148          * so the latter will not assign a new value to the pointer.
 149          *
 150          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 151          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 152          * value is crux of the synchronisation between ffs_func_eps_disable and
 153          * __ffs_epfile_read_data.
 154          *
 155          * Once __ffs_epfile_read_data is about to finish it will try to set the
 156          * pointer back to its old value (as described above), but seeing as the
 157          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 158          * the buffer.
 159          *
 160          * == State transitions ==
 161          *
 162          * • ptr == NULL:  (initial state)
 163          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 164          *   ◦ __ffs_epfile_read_buffered:    nop
 165          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 166          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 167          * • ptr == DROP:
 168          *   ◦ __ffs_epfile_read_buffer_free: nop
 169          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 170          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 171          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 172          * • ptr == buf:
 173          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 174          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 175          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 176          *                                    is always called first
 177          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 178          * • ptr == NULL and reading:
 179          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 180          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 181          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 182          *   ◦ reading finishes and …
 183          *     … all data read:               free buf, go to ptr == NULL
 184          *     … otherwise:                   go to ptr == buf and reading
 185          * • ptr == DROP and reading:
 186          *   ◦ __ffs_epfile_read_buffer_free: nop
 187          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 188          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 189          *   ◦ reading finishes:              free buf, go to ptr == DROP
 190          */
 191         struct ffs_buffer               *read_buffer;
 192 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 193
 194         char                            name[5];
 195
 196         unsigned char                   in;     /* P: ffs->eps_lock */
 197         unsigned char                   isoc;   /* P: ffs->eps_lock */
 198
 199         unsigned char                   _pad;
 200 };
 201
 202 struct ffs_buffer {
 203         size_t length;
 204         char *data;
 205         char storage[];
 206 };
 207
 208 /*  ffs_io_data structure ***************************************************/
 209
 210 struct ffs_io_data {
 211         bool aio;
 212         bool read;
 213
 214         struct kiocb *kiocb;
 215         struct iov_iter data;
 216         const void *to_free;
 217         char *buf;
 218
 219         struct mm_struct *mm;
 220         struct work_struct work;
 221
 222         struct usb_ep *ep;
 223         struct usb_request *req;
 224         struct sg_table sgt;
 225         bool use_sg;
 226
 227         struct ffs_data *ffs;
 228
 229         int status;
 230         struct completion done;
 231 };
 232
 233 struct ffs_desc_helper {
 234         struct ffs_data *ffs;
 235         unsigned interfaces_count;
 236         unsigned eps_count;
 237 };
 238
 239 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 240 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 241
 242 static struct dentry *
 243 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 244                    const struct file_operations *fops);
 245
 246 /* Devices management *******************************************************/
 247
 248 DEFINE_MUTEX(ffs_lock);
 249 EXPORT_SYMBOL_GPL(ffs_lock);
 250
 251 static struct ffs_dev *_ffs_find_dev(const char *name);
 252 static struct ffs_dev *_ffs_alloc_dev(void);
 253 static void _ffs_free_dev(struct ffs_dev *dev);
 254 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data);
 255 static void ffs_release_dev(struct ffs_dev *ffs_dev);
 256 static int ffs_ready(struct ffs_data *ffs);
 257 static void ffs_closed(struct ffs_data *ffs);
 258
 259 /* Misc helper functions ****************************************************/
 260
 261 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 262         __attribute__((warn_unused_result, nonnull));
 263 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 264         __attribute__((warn_unused_result, nonnull));
 265
 266
 267 /* Control file aka ep0 *****************************************************/
 268
 269 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 270 {
 271         struct ffs_data *ffs = req->context;
 272
 273         complete(&ffs->ep0req_completion);
 274 }
 275
 276 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 277         __releases(&ffs->ev.waitq.lock)
 278 {
 279         struct usb_request *req = ffs->ep0req;
 280         int ret;
 281
 282         if (!req) {
 283                 spin_unlock_irq(&ffs->ev.waitq.lock);
 284                 return -EINVAL;
 285         }
 286
 287         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 288
 289         spin_unlock_irq(&ffs->ev.waitq.lock);
 290
 291         req->buf      = data;
 292         req->length   = len;
 293
 294         /*
 295          * UDC layer requires to provide a buffer even for ZLP, but should
 296          * not use it at all. Let's provide some poisoned pointer to catch
 297          * possible bug in the driver.
 298          */
 299         if (req->buf == NULL)
 300                 req->buf = (void *)0xDEADBABE;
 301
 302         reinit_completion(&ffs->ep0req_completion);
 303
 304         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 305         if (ret < 0)
 306                 return ret;
 307
 308         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 309         if (ret) {
 310                 usb_ep_dequeue(ffs->gadget->ep0, req);
 311                 return -EINTR;
 312         }
 313
 314         ffs->setup_state = FFS_NO_SETUP;
 315         return req->status ? req->status : req->actual;
 316 }
 317
 318 static int __ffs_ep0_stall(struct ffs_data *ffs)
 319 {
 320         if (ffs->ev.can_stall) {
 321                 pr_vdebug("ep0 stall\n");
 322                 usb_ep_set_halt(ffs->gadget->ep0);
 323                 ffs->setup_state = FFS_NO_SETUP;
 324                 return -EL2HLT;
 325         } else {
 326                 pr_debug("bogus ep0 stall!\n");
 327                 return -ESRCH;
 328         }
 329 }
 330
 331 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 332                              size_t len, loff_t *ptr)
 333 {
 334         struct ffs_data *ffs = file->private_data;
 335         ssize_t ret;
 336         char *data;
 337
 338         /* Fast check if setup was canceled */
 339         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 340                 return -EIDRM;
 341
 342         /* Acquire mutex */
 343         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 344         if (ret < 0)
 345                 return ret;
 346
 347         /* Check state */
 348         switch (ffs->state) {
 349         case FFS_READ_DESCRIPTORS:
 350         case FFS_READ_STRINGS:
 351                 /* Copy data */
 352                 if (len < 16) {
 353                         ret = -EINVAL;
 354                         break;
 355                 }
 356
 357                 data = ffs_prepare_buffer(buf, len);
 358                 if (IS_ERR(data)) {
 359                         ret = PTR_ERR(data);
 360                         break;
 361                 }
 362
 363                 /* Handle data */
 364                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 365                         pr_info("read descriptors\n");
 366                         ret = __ffs_data_got_descs(ffs, data, len);
 367                         if (ret < 0)
 368                                 break;
 369
 370                         ffs->state = FFS_READ_STRINGS;
 371                         ret = len;
 372                 } else {
 373                         pr_info("read strings\n");
 374                         ret = __ffs_data_got_strings(ffs, data, len);
 375                         if (ret < 0)
 376                                 break;
 377
 378                         ret = ffs_epfiles_create(ffs);
 379                         if (ret) {
 380                                 ffs->state = FFS_CLOSING;
 381                                 break;
 382                         }
 383
 384                         ffs->state = FFS_ACTIVE;
 385                         mutex_unlock(&ffs->mutex);
 386
 387                         ret = ffs_ready(ffs);
 388                         if (ret < 0) {
 389                                 ffs->state = FFS_CLOSING;
 390                                 return ret;
 391                         }
 392
 393                         return len;
 394                 }
 395                 break;
 396
 397         case FFS_ACTIVE:
 398                 data = NULL;
 399                 /*
 400                  * We're called from user space, we can use _irq
 401                  * rather then _irqsave
 402                  */
 403                 spin_lock_irq(&ffs->ev.waitq.lock);
 404                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 405                 case FFS_SETUP_CANCELLED:
 406                         ret = -EIDRM;
 407                         goto done_spin;
 408
 409                 case FFS_NO_SETUP:
 410                         ret = -ESRCH;
 411                         goto done_spin;
 412
 413                 case FFS_SETUP_PENDING:
 414                         break;
 415                 }
 416
 417                 /* FFS_SETUP_PENDING */
 418                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 419                         spin_unlock_irq(&ffs->ev.waitq.lock);
 420                         ret = __ffs_ep0_stall(ffs);
 421                         break;
 422                 }
 423
 424                 /* FFS_SETUP_PENDING and not stall */
 425                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 426
 427                 spin_unlock_irq(&ffs->ev.waitq.lock);
 428
 429                 data = ffs_prepare_buffer(buf, len);
 430                 if (IS_ERR(data)) {
 431                         ret = PTR_ERR(data);
 432                         break;
 433                 }
 434
 435                 spin_lock_irq(&ffs->ev.waitq.lock);
 436
 437                 /*
 438                  * We are guaranteed to be still in FFS_ACTIVE state
 439                  * but the state of setup could have changed from
 440                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 441                  * to check for that.  If that happened we copied data
 442                  * from user space in vain but it's unlikely.
 443                  *
 444                  * For sure we are not in FFS_NO_SETUP since this is
 445                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 446                  * transition can be performed and it's protected by
 447                  * mutex.
 448                  */
 449                 if (ffs_setup_state_clear_cancelled(ffs) ==
 450                     FFS_SETUP_CANCELLED) {
 451                         ret = -EIDRM;
 452 done_spin:
 453                         spin_unlock_irq(&ffs->ev.waitq.lock);
 454                 } else {
 455                         /* unlocks spinlock */
 456                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 457                 }
 458                 kfree(data);
 459                 break;
 460
 461         default:
 462                 ret = -EBADFD;
 463                 break;
 464         }
 465
 466         mutex_unlock(&ffs->mutex);
 467         return ret;
 468 }
 469
 470 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 471 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 472                                      size_t n)
 473         __releases(&ffs->ev.waitq.lock)
 474 {
 475         /*
 476          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 477          * size of ffs->ev.types array (which is four) so that's how much space
 478          * we reserve.
 479          */
 480         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 481         const size_t size = n * sizeof *events;
 482         unsigned i = 0;
 483
 484         memset(events, 0, size);
 485
 486         do {
 487                 events[i].type = ffs->ev.types[i];
 488                 if (events[i].type == FUNCTIONFS_SETUP) {
 489                         events[i].u.setup = ffs->ev.setup;
 490                         ffs->setup_state = FFS_SETUP_PENDING;
 491                 }
 492         } while (++i < n);
 493
 494         ffs->ev.count -= n;
 495         if (ffs->ev.count)
 496                 memmove(ffs->ev.types, ffs->ev.types + n,
 497                         ffs->ev.count * sizeof *ffs->ev.types);
 498
 499         spin_unlock_irq(&ffs->ev.waitq.lock);
 500         mutex_unlock(&ffs->mutex);
 501
 502         return copy_to_user(buf, events, size) ? -EFAULT : size;
 503 }
 504
 505 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 506                             size_t len, loff_t *ptr)
 507 {
 508         struct ffs_data *ffs = file->private_data;
 509         char *data = NULL;
 510         size_t n;
 511         int ret;
 512
 513         /* Fast check if setup was canceled */
 514         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 515                 return -EIDRM;
 516
 517         /* Acquire mutex */
 518         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 519         if (ret < 0)
 520                 return ret;
 521
 522         /* Check state */
 523         if (ffs->state != FFS_ACTIVE) {
 524                 ret = -EBADFD;
 525                 goto done_mutex;
 526         }
 527
 528         /*
 529          * We're called from user space, we can use _irq rather then
 530          * _irqsave
 531          */
 532         spin_lock_irq(&ffs->ev.waitq.lock);
 533
 534         switch (ffs_setup_state_clear_cancelled(ffs)) {
 535         case FFS_SETUP_CANCELLED:
 536                 ret = -EIDRM;
 537                 break;
 538
 539         case FFS_NO_SETUP:
 540                 n = len / sizeof(struct usb_functionfs_event);
 541                 if (!n) {
 542                         ret = -EINVAL;
 543                         break;
 544                 }
 545
 546                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 547                         ret = -EAGAIN;
 548                         break;
 549                 }
 550
 551                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 552                                                         ffs->ev.count)) {
 553                         ret = -EINTR;
 554                         break;
 555                 }
 556
 557                 /* unlocks spinlock */
 558                 return __ffs_ep0_read_events(ffs, buf,
 559                                              min(n, (size_t)ffs->ev.count));
 560
 561         case FFS_SETUP_PENDING:
 562                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 563                         spin_unlock_irq(&ffs->ev.waitq.lock);
 564                         ret = __ffs_ep0_stall(ffs);
 565                         goto done_mutex;
 566                 }
 567
 568                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 569
 570                 spin_unlock_irq(&ffs->ev.waitq.lock);
 571
 572                 if (len) {
 573                         data = kmalloc(len, GFP_KERNEL);
 574                         if (!data) {
 575                                 ret = -ENOMEM;
 576                                 goto done_mutex;
 577                         }
 578                 }
 579
 580                 spin_lock_irq(&ffs->ev.waitq.lock);
 581
 582                 /* See ffs_ep0_write() */
 583                 if (ffs_setup_state_clear_cancelled(ffs) ==
 584                     FFS_SETUP_CANCELLED) {
 585                         ret = -EIDRM;
 586                         break;
 587                 }
 588
 589                 /* unlocks spinlock */
 590                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 591                 if ((ret > 0) && (copy_to_user(buf, data, len)))
 592                         ret = -EFAULT;
 593                 goto done_mutex;
 594
 595         default:
 596                 ret = -EBADFD;
 597                 break;
 598         }
 599
 600         spin_unlock_irq(&ffs->ev.waitq.lock);
 601 done_mutex:
 602         mutex_unlock(&ffs->mutex);
 603         kfree(data);
 604         return ret;
 605 }
 606
 607 static int ffs_ep0_open(struct inode *inode, struct file *file)
 608 {
 609         struct ffs_data *ffs = inode->i_private;
 610
 611         if (ffs->state == FFS_CLOSING)
 612                 return -EBUSY;
 613
 614         file->private_data = ffs;
 615         ffs_data_opened(ffs);
 616
 617         return stream_open(inode, file);
 618 }
 619
 620 static int ffs_ep0_release(struct inode *inode, struct file *file)
 621 {
 622         struct ffs_data *ffs = file->private_data;
 623
 624         ffs_data_closed(ffs);
 625
 626         return 0;
 627 }
 628
 629 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 630 {
 631         struct ffs_data *ffs = file->private_data;
 632         struct usb_gadget *gadget = ffs->gadget;
 633         long ret;
 634
 635         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 636                 struct ffs_function *func = ffs->func;
 637                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 638         } else if (gadget && gadget->ops->ioctl) {
 639                 ret = gadget->ops->ioctl(gadget, code, value);
 640         } else {
 641                 ret = -ENOTTY;
 642         }
 643
 644         return ret;
 645 }
 646
 647 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 648 {
 649         struct ffs_data *ffs = file->private_data;
 650         __poll_t mask = EPOLLWRNORM;
 651         int ret;
 652
 653         poll_wait(file, &ffs->ev.waitq, wait);
 654
 655         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 656         if (ret < 0)
 657                 return mask;
 658
 659         switch (ffs->state) {
 660         case FFS_READ_DESCRIPTORS:
 661         case FFS_READ_STRINGS:
 662                 mask |= EPOLLOUT;
 663                 break;
 664
 665         case FFS_ACTIVE:
 666                 switch (ffs->setup_state) {
 667                 case FFS_NO_SETUP:
 668                         if (ffs->ev.count)
 669                                 mask |= EPOLLIN;
 670                         break;
 671
 672                 case FFS_SETUP_PENDING:
 673                 case FFS_SETUP_CANCELLED:
 674                         mask |= (EPOLLIN | EPOLLOUT);
 675                         break;
 676                 }
 677                 break;
 678
 679         case FFS_CLOSING:
 680                 break;
 681         case FFS_DEACTIVATED:
 682                 break;
 683         }
 684
 685         mutex_unlock(&ffs->mutex);
 686
 687         return mask;
 688 }
 689
 690 static const struct file_operations ffs_ep0_operations = {
 691         .llseek =       no_llseek,
 692
 693         .open =         ffs_ep0_open,
 694         .write =        ffs_ep0_write,
 695         .read =         ffs_ep0_read,
 696         .release =      ffs_ep0_release,
 697         .unlocked_ioctl =       ffs_ep0_ioctl,
 698         .poll =         ffs_ep0_poll,
 699 };
 700
 701
 702 /* "Normal" endpoints operations ********************************************/
 703
 704 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 705 {
 706         struct ffs_io_data *io_data = req->context;
 707
 708         if (req->status)
 709                 io_data->status = req->status;
 710         else
 711                 io_data->status = req->actual;
 712
 713         complete(&io_data->done);
 714 }
 715
 716 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 717 {
 718         ssize_t ret = copy_to_iter(data, data_len, iter);
 719         if (ret == data_len)
 720                 return ret;
 721
 722         if (iov_iter_count(iter))
 723                 return -EFAULT;
 724
 725         /*
 726          * Dear user space developer!
 727          *
 728          * TL;DR: To stop getting below error message in your kernel log, change
 729          * user space code using functionfs to align read buffers to a max
 730          * packet size.
 731          *
 732          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 733          * packet size.  When unaligned buffer is passed to functionfs, it
 734          * internally uses a larger, aligned buffer so that such UDCs are happy.
 735          *
 736          * Unfortunately, this means that host may send more data than was
 737          * requested in read(2) system call.  f_fs doesn’t know what to do with
 738          * that excess data so it simply drops it.
 739          *
 740          * Was the buffer aligned in the first place, no such problem would
 741          * happen.
 742          *
 743          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 744          * by splitting a request into multiple parts.  This splitting may still
 745          * be a problem though so it’s likely best to align the buffer
 746          * regardless of it being AIO or not..
 747          *
 748          * This only affects OUT endpoints, i.e. reading data with a read(2),
 749          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 750          * affected.
 751          */
 752         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 753                "Align read buffer size to max packet size to avoid the problem.\n",
 754                data_len, ret);
 755
 756         return ret;
 757 }
 758
 759 /*
 760  * allocate a virtually contiguous buffer and create a scatterlist describing it
 761  * @sg_table    - pointer to a place to be filled with sg_table contents
 762  * @size        - required buffer size
 763  */
 764 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 765 {
 766         struct page **pages;
 767         void *vaddr, *ptr;
 768         unsigned int n_pages;
 769         int i;
 770
 771         vaddr = vmalloc(sz);
 772         if (!vaddr)
 773                 return NULL;
 774
 775         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 776         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 777         if (!pages) {
 778                 vfree(vaddr);
 779
 780                 return NULL;
 781         }
 782         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 783                 pages[i] = vmalloc_to_page(ptr);
 784
 785         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 786                 kvfree(pages);
 787                 vfree(vaddr);
 788
 789                 return NULL;
 790         }
 791         kvfree(pages);
 792
 793         return vaddr;
 794 }
 795
 796 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 797         size_t data_len)
 798 {
 799         if (io_data->use_sg)
 800                 return ffs_build_sg_list(&io_data->sgt, data_len);
 801
 802         return kmalloc(data_len, GFP_KERNEL);
 803 }
 804
 805 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 806 {
 807         if (!io_data->buf)
 808                 return;
 809
 810         if (io_data->use_sg) {
 811                 sg_free_table(&io_data->sgt);
 812                 vfree(io_data->buf);
 813         } else {
 814                 kfree(io_data->buf);
 815         }
 816 }
 817
 818 static void ffs_user_copy_worker(struct work_struct *work)
 819 {
 820         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 821                                                    work);
 822         int ret = io_data->status;
 823         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 824
 825         if (io_data->read && ret > 0) {
 826                 kthread_use_mm(io_data->mm);
 827                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 828                 kthread_unuse_mm(io_data->mm);
 829         }
 830
 831         io_data->kiocb->ki_complete(io_data->kiocb, ret);
 832
 833         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 834                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 835
 836         if (io_data->read)
 837                 kfree(io_data->to_free);
 838         ffs_free_buffer(io_data);
 839         kfree(io_data);
 840 }
 841
 842 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 843                                          struct usb_request *req)
 844 {
 845         struct ffs_io_data *io_data = req->context;
 846         struct ffs_data *ffs = io_data->ffs;
 847
 848         io_data->status = req->status ? req->status : req->actual;
 849         usb_ep_free_request(_ep, req);
 850
 851         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 852         queue_work(ffs->io_completion_wq, &io_data->work);
 853 }
 854
 855 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 856 {
 857         /*
 858          * See comment in struct ffs_epfile for full read_buffer pointer
 859          * synchronisation story.
 860          */
 861         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 862         if (buf && buf != READ_BUFFER_DROP)
 863                 kfree(buf);
 864 }
 865
 866 /* Assumes epfile->mutex is held. */
 867 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 868                                           struct iov_iter *iter)
 869 {
 870         /*
 871          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 872          * the buffer while we are using it.  See comment in struct ffs_epfile
 873          * for full read_buffer pointer synchronisation story.
 874          */
 875         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 876         ssize_t ret;
 877         if (!buf || buf == READ_BUFFER_DROP)
 878                 return 0;
 879
 880         ret = copy_to_iter(buf->data, buf->length, iter);
 881         if (buf->length == ret) {
 882                 kfree(buf);
 883                 return ret;
 884         }
 885
 886         if (iov_iter_count(iter)) {
 887                 ret = -EFAULT;
 888         } else {
 889                 buf->length -= ret;
 890                 buf->data += ret;
 891         }
 892
 893         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 894                 kfree(buf);
 895
 896         return ret;
 897 }
 898
 899 /* Assumes epfile->mutex is held. */
 900 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 901                                       void *data, int data_len,
 902                                       struct iov_iter *iter)
 903 {
 904         struct ffs_buffer *buf;
 905
 906         ssize_t ret = copy_to_iter(data, data_len, iter);
 907         if (data_len == ret)
 908                 return ret;
 909
 910         if (iov_iter_count(iter))
 911                 return -EFAULT;
 912
 913         /* See ffs_copy_to_iter for more context. */
 914         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 915                 data_len, ret);
 916
 917         data_len -= ret;
 918         buf = kmalloc(struct_size(buf, storage, data_len), GFP_KERNEL);
 919         if (!buf)
 920                 return -ENOMEM;
 921         buf->length = data_len;
 922         buf->data = buf->storage;
 923         memcpy(buf->storage, data + ret, flex_array_size(buf, storage, data_len));
 924
 925         /*
 926          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 927          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 928          * in struct ffs_epfile for full read_buffer pointer synchronisation
 929          * story.
 930          */
 931         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 932                 kfree(buf);
 933
 934         return ret;
 935 }
 936
 937 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 938 {
 939         struct ffs_epfile *epfile = file->private_data;
 940         struct usb_request *req;
 941         struct ffs_ep *ep;
 942         char *data = NULL;
 943         ssize_t ret, data_len = -EINVAL;
 944         int halt;
 945
 946         /* Are we still active? */
 947         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 948                 return -ENODEV;
 949
 950         /* Wait for endpoint to be enabled */
 951         ep = epfile->ep;
 952         if (!ep) {
 953                 if (file->f_flags & O_NONBLOCK)
 954                         return -EAGAIN;
 955
 956                 ret = wait_event_interruptible(
 957                                 epfile->ffs->wait, (ep = epfile->ep));
 958                 if (ret)
 959                         return -EINTR;
 960         }
 961
 962         /* Do we halt? */
 963         halt = (!io_data->read == !epfile->in);
 964         if (halt && epfile->isoc)
 965                 return -EINVAL;
 966
 967         /* We will be using request and read_buffer */
 968         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 969         if (ret)
 970                 goto error;
 971
 972         /* Allocate & copy */
 973         if (!halt) {
 974                 struct usb_gadget *gadget;
 975
 976                 /*
 977                  * Do we have buffered data from previous partial read?  Check
 978                  * that for synchronous case only because we do not have
 979                  * facility to ‘wake up’ a pending asynchronous read and push
 980                  * buffered data to it which we would need to make things behave
 981                  * consistently.
 982                  */
 983                 if (!io_data->aio && io_data->read) {
 984                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 985                         if (ret)
 986                                 goto error_mutex;
 987                 }
 988
 989                 /*
 990                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 991                  * before the waiting completes, so do not assign to 'gadget'
 992                  * earlier
 993                  */
 994                 gadget = epfile->ffs->gadget;
 995
 996                 spin_lock_irq(&epfile->ffs->eps_lock);
 997                 /* In the meantime, endpoint got disabled or changed. */
 998                 if (epfile->ep != ep) {
 999                         ret = -ESHUTDOWN;
1000                         goto error_lock;
1001                 }
1002                 data_len = iov_iter_count(&io_data->data);
1003                 /*
1004                  * Controller may require buffer size to be aligned to
1005                  * maxpacketsize of an out endpoint.
1006                  */
1007                 if (io_data->read)
1008                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1009
1010                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1011                 spin_unlock_irq(&epfile->ffs->eps_lock);
1012
1013                 data = ffs_alloc_buffer(io_data, data_len);
1014                 if (!data) {
1015                         ret = -ENOMEM;
1016                         goto error_mutex;
1017                 }
1018                 if (!io_data->read &&
1019                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1020                         ret = -EFAULT;
1021                         goto error_mutex;
1022                 }
1023         }
1024
1025         spin_lock_irq(&epfile->ffs->eps_lock);
1026
1027         if (epfile->ep != ep) {
1028                 /* In the meantime, endpoint got disabled or changed. */
1029                 ret = -ESHUTDOWN;
1030         } else if (halt) {
1031                 ret = usb_ep_set_halt(ep->ep);
1032                 if (!ret)
1033                         ret = -EBADMSG;
1034         } else if (data_len == -EINVAL) {
1035                 /*
1036                  * Sanity Check: even though data_len can't be used
1037                  * uninitialized at the time I write this comment, some
1038                  * compilers complain about this situation.
1039                  * In order to keep the code clean from warnings, data_len is
1040                  * being initialized to -EINVAL during its declaration, which
1041                  * means we can't rely on compiler anymore to warn no future
1042                  * changes won't result in data_len being used uninitialized.
1043                  * For such reason, we're adding this redundant sanity check
1044                  * here.
1045                  */
1046                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1047                 ret = -EINVAL;
1048         } else if (!io_data->aio) {
1049                 bool interrupted = false;
1050
1051                 req = ep->req;
1052                 if (io_data->use_sg) {
1053                         req->buf = NULL;
1054                         req->sg = io_data->sgt.sgl;
1055                         req->num_sgs = io_data->sgt.nents;
1056                 } else {
1057                         req->buf = data;
1058                         req->num_sgs = 0;
1059                 }
1060                 req->length = data_len;
1061
1062                 io_data->buf = data;
1063
1064                 init_completion(&io_data->done);
1065                 req->context  = io_data;
1066                 req->complete = ffs_epfile_io_complete;
1067
1068                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1069                 if (ret < 0)
1070                         goto error_lock;
1071
1072                 spin_unlock_irq(&epfile->ffs->eps_lock);
1073
1074                 if (wait_for_completion_interruptible(&io_data->done)) {
1075                         spin_lock_irq(&epfile->ffs->eps_lock);
1076                         if (epfile->ep != ep) {
1077                                 ret = -ESHUTDOWN;
1078                                 goto error_lock;
1079                         }
1080                         /*
1081                          * To avoid race condition with ffs_epfile_io_complete,
1082                          * dequeue the request first then check
1083                          * status. usb_ep_dequeue API should guarantee no race
1084                          * condition with req->complete callback.
1085                          */
1086                         usb_ep_dequeue(ep->ep, req);
1087                         spin_unlock_irq(&epfile->ffs->eps_lock);
1088                         wait_for_completion(&io_data->done);
1089                         interrupted = io_data->status < 0;
1090                 }
1091
1092                 if (interrupted)
1093                         ret = -EINTR;
1094                 else if (io_data->read && io_data->status > 0)
1095                         ret = __ffs_epfile_read_data(epfile, data, io_data->status,
1096                                                      &io_data->data);
1097                 else
1098                         ret = io_data->status;
1099                 goto error_mutex;
1100         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1101                 ret = -ENOMEM;
1102         } else {
1103                 if (io_data->use_sg) {
1104                         req->buf = NULL;
1105                         req->sg = io_data->sgt.sgl;
1106                         req->num_sgs = io_data->sgt.nents;
1107                 } else {
1108                         req->buf = data;
1109                         req->num_sgs = 0;
1110                 }
1111                 req->length = data_len;
1112
1113                 io_data->buf = data;
1114                 io_data->ep = ep->ep;
1115                 io_data->req = req;
1116                 io_data->ffs = epfile->ffs;
1117
1118                 req->context  = io_data;
1119                 req->complete = ffs_epfile_async_io_complete;
1120
1121                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1122                 if (ret) {
1123                         io_data->req = NULL;
1124                         usb_ep_free_request(ep->ep, req);
1125                         goto error_lock;
1126                 }
1127
1128                 ret = -EIOCBQUEUED;
1129                 /*
1130                  * Do not kfree the buffer in this function.  It will be freed
1131                  * by ffs_user_copy_worker.
1132                  */
1133                 data = NULL;
1134         }
1135
1136 error_lock:
1137         spin_unlock_irq(&epfile->ffs->eps_lock);
1138 error_mutex:
1139         mutex_unlock(&epfile->mutex);
1140 error:
1141         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1142                 ffs_free_buffer(io_data);
1143         return ret;
1144 }
1145
1146 static int
1147 ffs_epfile_open(struct inode *inode, struct file *file)
1148 {
1149         struct ffs_epfile *epfile = inode->i_private;
1150
1151         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1152                 return -ENODEV;
1153
1154         file->private_data = epfile;
1155         ffs_data_opened(epfile->ffs);
1156
1157         return stream_open(inode, file);
1158 }
1159
1160 static int ffs_aio_cancel(struct kiocb *kiocb)
1161 {
1162         struct ffs_io_data *io_data = kiocb->private;
1163         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1164         unsigned long flags;
1165         int value;
1166
1167         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1168
1169         if (io_data && io_data->ep && io_data->req)
1170                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1171         else
1172                 value = -EINVAL;
1173
1174         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1175
1176         return value;
1177 }
1178
1179 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1180 {
1181         struct ffs_io_data io_data, *p = &io_data;
1182         ssize_t res;
1183
1184         if (!is_sync_kiocb(kiocb)) {
1185                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1186                 if (!p)
1187                         return -ENOMEM;
1188                 p->aio = true;
1189         } else {
1190                 memset(p, 0, sizeof(*p));
1191                 p->aio = false;
1192         }
1193
1194         p->read = false;
1195         p->kiocb = kiocb;
1196         p->data = *from;
1197         p->mm = current->mm;
1198
1199         kiocb->private = p;
1200
1201         if (p->aio)
1202                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1203
1204         res = ffs_epfile_io(kiocb->ki_filp, p);
1205         if (res == -EIOCBQUEUED)
1206                 return res;
1207         if (p->aio)
1208                 kfree(p);
1209         else
1210                 *from = p->data;
1211         return res;
1212 }
1213
1214 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1215 {
1216         struct ffs_io_data io_data, *p = &io_data;
1217         ssize_t res;
1218
1219         if (!is_sync_kiocb(kiocb)) {
1220                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1221                 if (!p)
1222                         return -ENOMEM;
1223                 p->aio = true;
1224         } else {
1225                 memset(p, 0, sizeof(*p));
1226                 p->aio = false;
1227         }
1228
1229         p->read = true;
1230         p->kiocb = kiocb;
1231         if (p->aio) {
1232                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1233                 if (!iter_is_ubuf(&p->data) && !p->to_free) {
1234                         kfree(p);
1235                         return -ENOMEM;
1236                 }
1237         } else {
1238                 p->data = *to;
1239                 p->to_free = NULL;
1240         }
1241         p->mm = current->mm;
1242
1243         kiocb->private = p;
1244
1245         if (p->aio)
1246                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1247
1248         res = ffs_epfile_io(kiocb->ki_filp, p);
1249         if (res == -EIOCBQUEUED)
1250                 return res;
1251
1252         if (p->aio) {
1253                 kfree(p->to_free);
1254                 kfree(p);
1255         } else {
1256                 *to = p->data;
1257         }
1258         return res;
1259 }
1260
1261 static int
1262 ffs_epfile_release(struct inode *inode, struct file *file)
1263 {
1264         struct ffs_epfile *epfile = inode->i_private;
1265
1266         __ffs_epfile_read_buffer_free(epfile);
1267         ffs_data_closed(epfile->ffs);
1268
1269         return 0;
1270 }
1271
1272 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1273                              unsigned long value)
1274 {
1275         struct ffs_epfile *epfile = file->private_data;
1276         struct ffs_ep *ep;
1277         int ret;
1278
1279         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1280                 return -ENODEV;
1281
1282         /* Wait for endpoint to be enabled */
1283         ep = epfile->ep;
1284         if (!ep) {
1285                 if (file->f_flags & O_NONBLOCK)
1286                         return -EAGAIN;
1287
1288                 ret = wait_event_interruptible(
1289                                 epfile->ffs->wait, (ep = epfile->ep));
1290                 if (ret)
1291                         return -EINTR;
1292         }
1293
1294         spin_lock_irq(&epfile->ffs->eps_lock);
1295
1296         /* In the meantime, endpoint got disabled or changed. */
1297         if (epfile->ep != ep) {
1298                 spin_unlock_irq(&epfile->ffs->eps_lock);
1299                 return -ESHUTDOWN;
1300         }
1301
1302         switch (code) {
1303         case FUNCTIONFS_FIFO_STATUS:
1304                 ret = usb_ep_fifo_status(epfile->ep->ep);
1305                 break;
1306         case FUNCTIONFS_FIFO_FLUSH:
1307                 usb_ep_fifo_flush(epfile->ep->ep);
1308                 ret = 0;
1309                 break;
1310         case FUNCTIONFS_CLEAR_HALT:
1311                 ret = usb_ep_clear_halt(epfile->ep->ep);
1312                 break;
1313         case FUNCTIONFS_ENDPOINT_REVMAP:
1314                 ret = epfile->ep->num;
1315                 break;
1316         case FUNCTIONFS_ENDPOINT_DESC:
1317         {
1318                 int desc_idx;
1319                 struct usb_endpoint_descriptor desc1, *desc;
1320
1321                 switch (epfile->ffs->gadget->speed) {
1322                 case USB_SPEED_SUPER:
1323                 case USB_SPEED_SUPER_PLUS:
1324                         desc_idx = 2;
1325                         break;
1326                 case USB_SPEED_HIGH:
1327                         desc_idx = 1;
1328                         break;
1329                 default:
1330                         desc_idx = 0;
1331                 }
1332
1333                 desc = epfile->ep->descs[desc_idx];
1334                 memcpy(&desc1, desc, desc->bLength);
1335
1336                 spin_unlock_irq(&epfile->ffs->eps_lock);
1337                 ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
1338                 if (ret)
1339                         ret = -EFAULT;
1340                 return ret;
1341         }
1342         default:
1343                 ret = -ENOTTY;
1344         }
1345         spin_unlock_irq(&epfile->ffs->eps_lock);
1346
1347         return ret;
1348 }
1349
1350 static const struct file_operations ffs_epfile_operations = {
1351         .llseek =       no_llseek,
1352
1353         .open =         ffs_epfile_open,
1354         .write_iter =   ffs_epfile_write_iter,
1355         .read_iter =    ffs_epfile_read_iter,
1356         .release =      ffs_epfile_release,
1357         .unlocked_ioctl =       ffs_epfile_ioctl,
1358         .compat_ioctl = compat_ptr_ioctl,
1359 };
1360
1361
1362 /* File system and super block operations ***********************************/
1363
1364 /*
1365  * Mounting the file system creates a controller file, used first for
1366  * function configuration then later for event monitoring.
1367  */
1368
1369 static struct inode *__must_check
1370 ffs_sb_make_inode(struct super_block *sb, void *data,
1371                   const struct file_operations *fops,
1372                   const struct inode_operations *iops,
1373                   struct ffs_file_perms *perms)
1374 {
1375         struct inode *inode;
1376
1377         inode = new_inode(sb);
1378
1379         if (inode) {
1380                 struct timespec64 ts = current_time(inode);
1381
1382                 inode->i_ino     = get_next_ino();
1383                 inode->i_mode    = perms->mode;
1384                 inode->i_uid     = perms->uid;
1385                 inode->i_gid     = perms->gid;
1386                 inode->i_atime   = ts;
1387                 inode->i_mtime   = ts;
1388                 inode->i_ctime   = ts;
1389                 inode->i_private = data;
1390                 if (fops)
1391                         inode->i_fop = fops;
1392                 if (iops)
1393                         inode->i_op  = iops;
1394         }
1395
1396         return inode;
1397 }
1398
1399 /* Create "regular" file */
1400 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1401                                         const char *name, void *data,
1402                                         const struct file_operations *fops)
1403 {
1404         struct ffs_data *ffs = sb->s_fs_info;
1405         struct dentry   *dentry;
1406         struct inode    *inode;
1407
1408         dentry = d_alloc_name(sb->s_root, name);
1409         if (!dentry)
1410                 return NULL;
1411
1412         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1413         if (!inode) {
1414                 dput(dentry);
1415                 return NULL;
1416         }
1417
1418         d_add(dentry, inode);
1419         return dentry;
1420 }
1421
1422 /* Super block */
1423 static const struct super_operations ffs_sb_operations = {
1424         .statfs =       simple_statfs,
1425         .drop_inode =   generic_delete_inode,
1426 };
1427
1428 struct ffs_sb_fill_data {
1429         struct ffs_file_perms perms;
1430         umode_t root_mode;
1431         const char *dev_name;
1432         bool no_disconnect;
1433         struct ffs_data *ffs_data;
1434 };
1435
1436 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1437 {
1438         struct ffs_sb_fill_data *data = fc->fs_private;
1439         struct inode    *inode;
1440         struct ffs_data *ffs = data->ffs_data;
1441
1442         ffs->sb              = sb;
1443         data->ffs_data       = NULL;
1444         sb->s_fs_info        = ffs;
1445         sb->s_blocksize      = PAGE_SIZE;
1446         sb->s_blocksize_bits = PAGE_SHIFT;
1447         sb->s_magic          = FUNCTIONFS_MAGIC;
1448         sb->s_op             = &ffs_sb_operations;
1449         sb->s_time_gran      = 1;
1450
1451         /* Root inode */
1452         data->perms.mode = data->root_mode;
1453         inode = ffs_sb_make_inode(sb, NULL,
1454                                   &simple_dir_operations,
1455                                   &simple_dir_inode_operations,
1456                                   &data->perms);
1457         sb->s_root = d_make_root(inode);
1458         if (!sb->s_root)
1459                 return -ENOMEM;
1460
1461         /* EP0 file */
1462         if (!ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations))
1463                 return -ENOMEM;
1464
1465         return 0;
1466 }
1467
1468 enum {
1469         Opt_no_disconnect,
1470         Opt_rmode,
1471         Opt_fmode,
1472         Opt_mode,
1473         Opt_uid,
1474         Opt_gid,
1475 };
1476
1477 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1478         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1479         fsparam_u32     ("rmode",               Opt_rmode),
1480         fsparam_u32     ("fmode",               Opt_fmode),
1481         fsparam_u32     ("mode",                Opt_mode),
1482         fsparam_u32     ("uid",                 Opt_uid),
1483         fsparam_u32     ("gid",                 Opt_gid),
1484         {}
1485 };
1486
1487 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1488 {
1489         struct ffs_sb_fill_data *data = fc->fs_private;
1490         struct fs_parse_result result;
1491         int opt;
1492
1493         opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1494         if (opt < 0)
1495                 return opt;
1496
1497         switch (opt) {
1498         case Opt_no_disconnect:
1499                 data->no_disconnect = result.boolean;
1500                 break;
1501         case Opt_rmode:
1502                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1503                 break;
1504         case Opt_fmode:
1505                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1506                 break;
1507         case Opt_mode:
1508                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1509                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1510                 break;
1511
1512         case Opt_uid:
1513                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1514                 if (!uid_valid(data->perms.uid))
1515                         goto unmapped_value;
1516                 break;
1517         case Opt_gid:
1518                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1519                 if (!gid_valid(data->perms.gid))
1520                         goto unmapped_value;
1521                 break;
1522
1523         default:
1524                 return -ENOPARAM;
1525         }
1526
1527         return 0;
1528
1529 unmapped_value:
1530         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1531 }
1532
1533 /*
1534  * Set up the superblock for a mount.
1535  */
1536 static int ffs_fs_get_tree(struct fs_context *fc)
1537 {
1538         struct ffs_sb_fill_data *ctx = fc->fs_private;
1539         struct ffs_data *ffs;
1540         int ret;
1541
1542         if (!fc->source)
1543                 return invalf(fc, "No source specified");
1544
1545         ffs = ffs_data_new(fc->source);
1546         if (!ffs)
1547                 return -ENOMEM;
1548         ffs->file_perms = ctx->perms;
1549         ffs->no_disconnect = ctx->no_disconnect;
1550
1551         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1552         if (!ffs->dev_name) {
1553                 ffs_data_put(ffs);
1554                 return -ENOMEM;
1555         }
1556
1557         ret = ffs_acquire_dev(ffs->dev_name, ffs);
1558         if (ret) {
1559                 ffs_data_put(ffs);
1560                 return ret;
1561         }
1562
1563         ctx->ffs_data = ffs;
1564         return get_tree_nodev(fc, ffs_sb_fill);
1565 }
1566
1567 static void ffs_fs_free_fc(struct fs_context *fc)
1568 {
1569         struct ffs_sb_fill_data *ctx = fc->fs_private;
1570
1571         if (ctx) {
1572                 if (ctx->ffs_data) {
1573                         ffs_data_put(ctx->ffs_data);
1574                 }
1575
1576                 kfree(ctx);
1577         }
1578 }
1579
1580 static const struct fs_context_operations ffs_fs_context_ops = {
1581         .free           = ffs_fs_free_fc,
1582         .parse_param    = ffs_fs_parse_param,
1583         .get_tree       = ffs_fs_get_tree,
1584 };
1585
1586 static int ffs_fs_init_fs_context(struct fs_context *fc)
1587 {
1588         struct ffs_sb_fill_data *ctx;
1589
1590         ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1591         if (!ctx)
1592                 return -ENOMEM;
1593
1594         ctx->perms.mode = S_IFREG | 0600;
1595         ctx->perms.uid = GLOBAL_ROOT_UID;
1596         ctx->perms.gid = GLOBAL_ROOT_GID;
1597         ctx->root_mode = S_IFDIR | 0500;
1598         ctx->no_disconnect = false;
1599
1600         fc->fs_private = ctx;
1601         fc->ops = &ffs_fs_context_ops;
1602         return 0;
1603 }
1604
1605 static void
1606 ffs_fs_kill_sb(struct super_block *sb)
1607 {
1608         kill_litter_super(sb);
1609         if (sb->s_fs_info)
1610                 ffs_data_closed(sb->s_fs_info);
1611 }
1612
1613 static struct file_system_type ffs_fs_type = {
1614         .owner          = THIS_MODULE,
1615         .name           = "functionfs",
1616         .init_fs_context = ffs_fs_init_fs_context,
1617         .parameters     = ffs_fs_fs_parameters,
1618         .kill_sb        = ffs_fs_kill_sb,
1619 };
1620 MODULE_ALIAS_FS("functionfs");
1621
1622
1623 /* Driver's main init/cleanup functions *************************************/
1624
1625 static int functionfs_init(void)
1626 {
1627         int ret;
1628
1629         ret = register_filesystem(&ffs_fs_type);
1630         if (!ret)
1631                 pr_info("file system registered\n");
1632         else
1633                 pr_err("failed registering file system (%d)\n", ret);
1634
1635         return ret;
1636 }
1637
1638 static void functionfs_cleanup(void)
1639 {
1640         pr_info("unloading\n");
1641         unregister_filesystem(&ffs_fs_type);
1642 }
1643
1644
1645 /* ffs_data and ffs_function construction and destruction code **************/
1646
1647 static void ffs_data_clear(struct ffs_data *ffs);
1648 static void ffs_data_reset(struct ffs_data *ffs);
1649
1650 static void ffs_data_get(struct ffs_data *ffs)
1651 {
1652         refcount_inc(&ffs->ref);
1653 }
1654
1655 static void ffs_data_opened(struct ffs_data *ffs)
1656 {
1657         refcount_inc(&ffs->ref);
1658         if (atomic_add_return(1, &ffs->opened) == 1 &&
1659                         ffs->state == FFS_DEACTIVATED) {
1660                 ffs->state = FFS_CLOSING;
1661                 ffs_data_reset(ffs);
1662         }
1663 }
1664
1665 static void ffs_data_put(struct ffs_data *ffs)
1666 {
1667         if (refcount_dec_and_test(&ffs->ref)) {
1668                 pr_info("%s(): freeing\n", __func__);
1669                 ffs_data_clear(ffs);
1670                 ffs_release_dev(ffs->private_data);
1671                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1672                        swait_active(&ffs->ep0req_completion.wait) ||
1673                        waitqueue_active(&ffs->wait));
1674                 destroy_workqueue(ffs->io_completion_wq);
1675                 kfree(ffs->dev_name);
1676                 kfree(ffs);
1677         }
1678 }
1679
1680 static void ffs_data_closed(struct ffs_data *ffs)
1681 {
1682         struct ffs_epfile *epfiles;
1683         unsigned long flags;
1684
1685         if (atomic_dec_and_test(&ffs->opened)) {
1686                 if (ffs->no_disconnect) {
1687                         ffs->state = FFS_DEACTIVATED;
1688                         spin_lock_irqsave(&ffs->eps_lock, flags);
1689                         epfiles = ffs->epfiles;
1690                         ffs->epfiles = NULL;
1691                         spin_unlock_irqrestore(&ffs->eps_lock,
1692                                                         flags);
1693
1694                         if (epfiles)
1695                                 ffs_epfiles_destroy(epfiles,
1696                                                  ffs->eps_count);
1697
1698                         if (ffs->setup_state == FFS_SETUP_PENDING)
1699                                 __ffs_ep0_stall(ffs);
1700                 } else {
1701                         ffs->state = FFS_CLOSING;
1702                         ffs_data_reset(ffs);
1703                 }
1704         }
1705         if (atomic_read(&ffs->opened) < 0) {
1706                 ffs->state = FFS_CLOSING;
1707                 ffs_data_reset(ffs);
1708         }
1709
1710         ffs_data_put(ffs);
1711 }
1712
1713 static struct ffs_data *ffs_data_new(const char *dev_name)
1714 {
1715         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1716         if (!ffs)
1717                 return NULL;
1718
1719         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1720         if (!ffs->io_completion_wq) {
1721                 kfree(ffs);
1722                 return NULL;
1723         }
1724
1725         refcount_set(&ffs->ref, 1);
1726         atomic_set(&ffs->opened, 0);
1727         ffs->state = FFS_READ_DESCRIPTORS;
1728         mutex_init(&ffs->mutex);
1729         spin_lock_init(&ffs->eps_lock);
1730         init_waitqueue_head(&ffs->ev.waitq);
1731         init_waitqueue_head(&ffs->wait);
1732         init_completion(&ffs->ep0req_completion);
1733
1734         /* XXX REVISIT need to update it in some places, or do we? */
1735         ffs->ev.can_stall = 1;
1736
1737         return ffs;
1738 }
1739
1740 static void ffs_data_clear(struct ffs_data *ffs)
1741 {
1742         struct ffs_epfile *epfiles;
1743         unsigned long flags;
1744
1745         ffs_closed(ffs);
1746
1747         BUG_ON(ffs->gadget);
1748
1749         spin_lock_irqsave(&ffs->eps_lock, flags);
1750         epfiles = ffs->epfiles;
1751         ffs->epfiles = NULL;
1752         spin_unlock_irqrestore(&ffs->eps_lock, flags);
1753
1754         /*
1755          * potential race possible between ffs_func_eps_disable
1756          * & ffs_epfile_release therefore maintaining a local
1757          * copy of epfile will save us from use-after-free.
1758          */
1759         if (epfiles) {
1760                 ffs_epfiles_destroy(epfiles, ffs->eps_count);
1761                 ffs->epfiles = NULL;
1762         }
1763
1764         if (ffs->ffs_eventfd) {
1765                 eventfd_ctx_put(ffs->ffs_eventfd);
1766                 ffs->ffs_eventfd = NULL;
1767         }
1768
1769         kfree(ffs->raw_descs_data);
1770         kfree(ffs->raw_strings);
1771         kfree(ffs->stringtabs);
1772 }
1773
1774 static void ffs_data_reset(struct ffs_data *ffs)
1775 {
1776         ffs_data_clear(ffs);
1777
1778         ffs->raw_descs_data = NULL;
1779         ffs->raw_descs = NULL;
1780         ffs->raw_strings = NULL;
1781         ffs->stringtabs = NULL;
1782
1783         ffs->raw_descs_length = 0;
1784         ffs->fs_descs_count = 0;
1785         ffs->hs_descs_count = 0;
1786         ffs->ss_descs_count = 0;
1787
1788         ffs->strings_count = 0;
1789         ffs->interfaces_count = 0;
1790         ffs->eps_count = 0;
1791
1792         ffs->ev.count = 0;
1793
1794         ffs->state = FFS_READ_DESCRIPTORS;
1795         ffs->setup_state = FFS_NO_SETUP;
1796         ffs->flags = 0;
1797
1798         ffs->ms_os_descs_ext_prop_count = 0;
1799         ffs->ms_os_descs_ext_prop_name_len = 0;
1800         ffs->ms_os_descs_ext_prop_data_len = 0;
1801 }
1802
1803
1804 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1805 {
1806         struct usb_gadget_strings **lang;
1807         int first_id;
1808
1809         if (WARN_ON(ffs->state != FFS_ACTIVE
1810                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1811                 return -EBADFD;
1812
1813         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1814         if (first_id < 0)
1815                 return first_id;
1816
1817         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1818         if (!ffs->ep0req)
1819                 return -ENOMEM;
1820         ffs->ep0req->complete = ffs_ep0_complete;
1821         ffs->ep0req->context = ffs;
1822
1823         lang = ffs->stringtabs;
1824         if (lang) {
1825                 for (; *lang; ++lang) {
1826                         struct usb_string *str = (*lang)->strings;
1827                         int id = first_id;
1828                         for (; str->s; ++id, ++str)
1829                                 str->id = id;
1830                 }
1831         }
1832
1833         ffs->gadget = cdev->gadget;
1834         ffs_data_get(ffs);
1835         return 0;
1836 }
1837
1838 static void functionfs_unbind(struct ffs_data *ffs)
1839 {
1840         if (!WARN_ON(!ffs->gadget)) {
1841                 /* dequeue before freeing ep0req */
1842                 usb_ep_dequeue(ffs->gadget->ep0, ffs->ep0req);
1843                 mutex_lock(&ffs->mutex);
1844                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1845                 ffs->ep0req = NULL;
1846                 ffs->gadget = NULL;
1847                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1848                 mutex_unlock(&ffs->mutex);
1849                 ffs_data_put(ffs);
1850         }
1851 }
1852
1853 static int ffs_epfiles_create(struct ffs_data *ffs)
1854 {
1855         struct ffs_epfile *epfile, *epfiles;
1856         unsigned i, count;
1857
1858         count = ffs->eps_count;
1859         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1860         if (!epfiles)
1861                 return -ENOMEM;
1862
1863         epfile = epfiles;
1864         for (i = 1; i <= count; ++i, ++epfile) {
1865                 epfile->ffs = ffs;
1866                 mutex_init(&epfile->mutex);
1867                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1868                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1869                 else
1870                         sprintf(epfile->name, "ep%u", i);
1871                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1872                                                  epfile,
1873                                                  &ffs_epfile_operations);
1874                 if (!epfile->dentry) {
1875                         ffs_epfiles_destroy(epfiles, i - 1);
1876                         return -ENOMEM;
1877                 }
1878         }
1879
1880         ffs->epfiles = epfiles;
1881         return 0;
1882 }
1883
1884 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1885 {
1886         struct ffs_epfile *epfile = epfiles;
1887
1888         for (; count; --count, ++epfile) {
1889                 BUG_ON(mutex_is_locked(&epfile->mutex));
1890                 if (epfile->dentry) {
1891                         d_delete(epfile->dentry);
1892                         dput(epfile->dentry);
1893                         epfile->dentry = NULL;
1894                 }
1895         }
1896
1897         kfree(epfiles);
1898 }
1899
1900 static void ffs_func_eps_disable(struct ffs_function *func)
1901 {
1902         struct ffs_ep *ep;
1903         struct ffs_epfile *epfile;
1904         unsigned short count;
1905         unsigned long flags;
1906
1907         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1908         count = func->ffs->eps_count;
1909         epfile = func->ffs->epfiles;
1910         ep = func->eps;
1911         while (count--) {
1912                 /* pending requests get nuked */
1913                 if (ep->ep)
1914                         usb_ep_disable(ep->ep);
1915                 ++ep;
1916
1917                 if (epfile) {
1918                         epfile->ep = NULL;
1919                         __ffs_epfile_read_buffer_free(epfile);
1920                         ++epfile;
1921                 }
1922         }
1923         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1924 }
1925
1926 static int ffs_func_eps_enable(struct ffs_function *func)
1927 {
1928         struct ffs_data *ffs;
1929         struct ffs_ep *ep;
1930         struct ffs_epfile *epfile;
1931         unsigned short count;
1932         unsigned long flags;
1933         int ret = 0;
1934
1935         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1936         ffs = func->ffs;
1937         ep = func->eps;
1938         epfile = ffs->epfiles;
1939         count = ffs->eps_count;
1940         while(count--) {
1941                 ep->ep->driver_data = ep;
1942
1943                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1944                 if (ret) {
1945                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1946                                         __func__, ep->ep->name, ret);
1947                         break;
1948                 }
1949
1950                 ret = usb_ep_enable(ep->ep);
1951                 if (!ret) {
1952                         epfile->ep = ep;
1953                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1954                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1955                 } else {
1956                         break;
1957                 }
1958
1959                 ++ep;
1960                 ++epfile;
1961         }
1962
1963         wake_up_interruptible(&ffs->wait);
1964         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1965
1966         return ret;
1967 }
1968
1969
1970 /* Parsing and building descriptors and strings *****************************/
1971
1972 /*
1973  * This validates if data pointed by data is a valid USB descriptor as
1974  * well as record how many interfaces, endpoints and strings are
1975  * required by given configuration.  Returns address after the
1976  * descriptor or NULL if data is invalid.
1977  */
1978
1979 enum ffs_entity_type {
1980         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1981 };
1982
1983 enum ffs_os_desc_type {
1984         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1985 };
1986
1987 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1988                                    u8 *valuep,
1989                                    struct usb_descriptor_header *desc,
1990                                    void *priv);
1991
1992 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1993                                     struct usb_os_desc_header *h, void *data,
1994                                     unsigned len, void *priv);
1995
1996 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1997                                            ffs_entity_callback entity,
1998                                            void *priv, int *current_class)
1999 {
2000         struct usb_descriptor_header *_ds = (void *)data;
2001         u8 length;
2002         int ret;
2003
2004         /* At least two bytes are required: length and type */
2005         if (len < 2) {
2006                 pr_vdebug("descriptor too short\n");
2007                 return -EINVAL;
2008         }
2009
2010         /* If we have at least as many bytes as the descriptor takes? */
2011         length = _ds->bLength;
2012         if (len < length) {
2013                 pr_vdebug("descriptor longer then available data\n");
2014                 return -EINVAL;
2015         }
2016
2017 #define __entity_check_INTERFACE(val)  1
2018 #define __entity_check_STRING(val)     (val)
2019 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2020 #define __entity(type, val) do {                                        \
2021                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2022                 if (!__entity_check_ ##type(val)) {                     \
2023                         pr_vdebug("invalid entity's value\n");          \
2024                         return -EINVAL;                                 \
2025                 }                                                       \
2026                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2027                 if (ret < 0) {                                          \
2028                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2029                                  (val), ret);                           \
2030                         return ret;                                     \
2031                 }                                                       \
2032         } while (0)
2033
2034         /* Parse descriptor depending on type. */
2035         switch (_ds->bDescriptorType) {
2036         case USB_DT_DEVICE:
2037         case USB_DT_CONFIG:
2038         case USB_DT_STRING:
2039         case USB_DT_DEVICE_QUALIFIER:
2040                 /* function can't have any of those */
2041                 pr_vdebug("descriptor reserved for gadget: %d\n",
2042                       _ds->bDescriptorType);
2043                 return -EINVAL;
2044
2045         case USB_DT_INTERFACE: {
2046                 struct usb_interface_descriptor *ds = (void *)_ds;
2047                 pr_vdebug("interface descriptor\n");
2048                 if (length != sizeof *ds)
2049                         goto inv_length;
2050
2051                 __entity(INTERFACE, ds->bInterfaceNumber);
2052                 if (ds->iInterface)
2053                         __entity(STRING, ds->iInterface);
2054                 *current_class = ds->bInterfaceClass;
2055         }
2056                 break;
2057
2058         case USB_DT_ENDPOINT: {
2059                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2060                 pr_vdebug("endpoint descriptor\n");
2061                 if (length != USB_DT_ENDPOINT_SIZE &&
2062                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2063                         goto inv_length;
2064                 __entity(ENDPOINT, ds->bEndpointAddress);
2065         }
2066                 break;
2067
2068         case USB_TYPE_CLASS | 0x01:
2069                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2070                         pr_vdebug("hid descriptor\n");
2071                         if (length != sizeof(struct hid_descriptor))
2072                                 goto inv_length;
2073                         break;
2074                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2075                         pr_vdebug("ccid descriptor\n");
2076                         if (length != sizeof(struct ccid_descriptor))
2077                                 goto inv_length;
2078                         break;
2079                 } else {
2080                         pr_vdebug("unknown descriptor: %d for class %d\n",
2081                               _ds->bDescriptorType, *current_class);
2082                         return -EINVAL;
2083                 }
2084
2085         case USB_DT_OTG:
2086                 if (length != sizeof(struct usb_otg_descriptor))
2087                         goto inv_length;
2088                 break;
2089
2090         case USB_DT_INTERFACE_ASSOCIATION: {
2091                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2092                 pr_vdebug("interface association descriptor\n");
2093                 if (length != sizeof *ds)
2094                         goto inv_length;
2095                 if (ds->iFunction)
2096                         __entity(STRING, ds->iFunction);
2097         }
2098                 break;
2099
2100         case USB_DT_SS_ENDPOINT_COMP:
2101                 pr_vdebug("EP SS companion descriptor\n");
2102                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2103                         goto inv_length;
2104                 break;
2105
2106         case USB_DT_OTHER_SPEED_CONFIG:
2107         case USB_DT_INTERFACE_POWER:
2108         case USB_DT_DEBUG:
2109         case USB_DT_SECURITY:
2110         case USB_DT_CS_RADIO_CONTROL:
2111                 /* TODO */
2112                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2113                 return -EINVAL;
2114
2115         default:
2116                 /* We should never be here */
2117                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2118                 return -EINVAL;
2119
2120 inv_length:
2121                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2122                           _ds->bLength, _ds->bDescriptorType);
2123                 return -EINVAL;
2124         }
2125
2126 #undef __entity
2127 #undef __entity_check_DESCRIPTOR
2128 #undef __entity_check_INTERFACE
2129 #undef __entity_check_STRING
2130 #undef __entity_check_ENDPOINT
2131
2132         return length;
2133 }
2134
2135 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2136                                      ffs_entity_callback entity, void *priv)
2137 {
2138         const unsigned _len = len;
2139         unsigned long num = 0;
2140         int current_class = -1;
2141
2142         for (;;) {
2143                 int ret;
2144
2145                 if (num == count)
2146                         data = NULL;
2147
2148                 /* Record "descriptor" entity */
2149                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2150                 if (ret < 0) {
2151                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2152                                  num, ret);
2153                         return ret;
2154                 }
2155
2156                 if (!data)
2157                         return _len - len;
2158
2159                 ret = ffs_do_single_desc(data, len, entity, priv,
2160                         &current_class);
2161                 if (ret < 0) {
2162                         pr_debug("%s returns %d\n", __func__, ret);
2163                         return ret;
2164                 }
2165
2166                 len -= ret;
2167                 data += ret;
2168                 ++num;
2169         }
2170 }
2171
2172 static int __ffs_data_do_entity(enum ffs_entity_type type,
2173                                 u8 *valuep, struct usb_descriptor_header *desc,
2174                                 void *priv)
2175 {
2176         struct ffs_desc_helper *helper = priv;
2177         struct usb_endpoint_descriptor *d;
2178
2179         switch (type) {
2180         case FFS_DESCRIPTOR:
2181                 break;
2182
2183         case FFS_INTERFACE:
2184                 /*
2185                  * Interfaces are indexed from zero so if we
2186                  * encountered interface "n" then there are at least
2187                  * "n+1" interfaces.
2188                  */
2189                 if (*valuep >= helper->interfaces_count)
2190                         helper->interfaces_count = *valuep + 1;
2191                 break;
2192
2193         case FFS_STRING:
2194                 /*
2195                  * Strings are indexed from 1 (0 is reserved
2196                  * for languages list)
2197                  */
2198                 if (*valuep > helper->ffs->strings_count)
2199                         helper->ffs->strings_count = *valuep;
2200                 break;
2201
2202         case FFS_ENDPOINT:
2203                 d = (void *)desc;
2204                 helper->eps_count++;
2205                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2206                         return -EINVAL;
2207                 /* Check if descriptors for any speed were already parsed */
2208                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2209                         helper->ffs->eps_addrmap[helper->eps_count] =
2210                                 d->bEndpointAddress;
2211                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2212                                 d->bEndpointAddress)
2213                         return -EINVAL;
2214                 break;
2215         }
2216
2217         return 0;
2218 }
2219
2220 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2221                                    struct usb_os_desc_header *desc)
2222 {
2223         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2224         u16 w_index = le16_to_cpu(desc->wIndex);
2225
2226         if (bcd_version == 0x1) {
2227                 pr_warn("bcdVersion must be 0x0100, stored in Little Endian order. "
2228                         "Userspace driver should be fixed, accepting 0x0001 for compatibility.\n");
2229         } else if (bcd_version != 0x100) {
2230                 pr_vdebug("unsupported os descriptors version: 0x%x\n",
2231                           bcd_version);
2232                 return -EINVAL;
2233         }
2234         switch (w_index) {
2235         case 0x4:
2236                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2237                 break;
2238         case 0x5:
2239                 *next_type = FFS_OS_DESC_EXT_PROP;
2240                 break;
2241         default:
2242                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2243                 return -EINVAL;
2244         }
2245
2246         return sizeof(*desc);
2247 }
2248
2249 /*
2250  * Process all extended compatibility/extended property descriptors
2251  * of a feature descriptor
2252  */
2253 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2254                                               enum ffs_os_desc_type type,
2255                                               u16 feature_count,
2256                                               ffs_os_desc_callback entity,
2257                                               void *priv,
2258                                               struct usb_os_desc_header *h)
2259 {
2260         int ret;
2261         const unsigned _len = len;
2262
2263         /* loop over all ext compat/ext prop descriptors */
2264         while (feature_count--) {
2265                 ret = entity(type, h, data, len, priv);
2266                 if (ret < 0) {
2267                         pr_debug("bad OS descriptor, type: %d\n", type);
2268                         return ret;
2269                 }
2270                 data += ret;
2271                 len -= ret;
2272         }
2273         return _len - len;
2274 }
2275
2276 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2277 static int __must_check ffs_do_os_descs(unsigned count,
2278                                         char *data, unsigned len,
2279                                         ffs_os_desc_callback entity, void *priv)
2280 {
2281         const unsigned _len = len;
2282         unsigned long num = 0;
2283
2284         for (num = 0; num < count; ++num) {
2285                 int ret;
2286                 enum ffs_os_desc_type type;
2287                 u16 feature_count;
2288                 struct usb_os_desc_header *desc = (void *)data;
2289
2290                 if (len < sizeof(*desc))
2291                         return -EINVAL;
2292
2293                 /*
2294                  * Record "descriptor" entity.
2295                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2296                  * Move the data pointer to the beginning of extended
2297                  * compatibilities proper or extended properties proper
2298                  * portions of the data
2299                  */
2300                 if (le32_to_cpu(desc->dwLength) > len)
2301                         return -EINVAL;
2302
2303                 ret = __ffs_do_os_desc_header(&type, desc);
2304                 if (ret < 0) {
2305                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2306                                  num, ret);
2307                         return ret;
2308                 }
2309                 /*
2310                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2311                  */
2312                 feature_count = le16_to_cpu(desc->wCount);
2313                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2314                     (feature_count > 255 || desc->Reserved))
2315                                 return -EINVAL;
2316                 len -= ret;
2317                 data += ret;
2318
2319                 /*
2320                  * Process all function/property descriptors
2321                  * of this Feature Descriptor
2322                  */
2323                 ret = ffs_do_single_os_desc(data, len, type,
2324                                             feature_count, entity, priv, desc);
2325                 if (ret < 0) {
2326                         pr_debug("%s returns %d\n", __func__, ret);
2327                         return ret;
2328                 }
2329
2330                 len -= ret;
2331                 data += ret;
2332         }
2333         return _len - len;
2334 }
2335
2336 /*
2337  * Validate contents of the buffer from userspace related to OS descriptors.
2338  */
2339 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2340                                  struct usb_os_desc_header *h, void *data,
2341                                  unsigned len, void *priv)
2342 {
2343         struct ffs_data *ffs = priv;
2344         u8 length;
2345
2346         switch (type) {
2347         case FFS_OS_DESC_EXT_COMPAT: {
2348                 struct usb_ext_compat_desc *d = data;
2349                 int i;
2350
2351                 if (len < sizeof(*d) ||
2352                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2353                         return -EINVAL;
2354                 if (d->Reserved1 != 1) {
2355                         /*
2356                          * According to the spec, Reserved1 must be set to 1
2357                          * but older kernels incorrectly rejected non-zero
2358                          * values.  We fix it here to avoid returning EINVAL
2359                          * in response to values we used to accept.
2360                          */
2361                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2362                         d->Reserved1 = 1;
2363                 }
2364                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2365                         if (d->Reserved2[i])
2366                                 return -EINVAL;
2367
2368                 length = sizeof(struct usb_ext_compat_desc);
2369         }
2370                 break;
2371         case FFS_OS_DESC_EXT_PROP: {
2372                 struct usb_ext_prop_desc *d = data;
2373                 u32 type, pdl;
2374                 u16 pnl;
2375
2376                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2377                         return -EINVAL;
2378                 length = le32_to_cpu(d->dwSize);
2379                 if (len < length)
2380                         return -EINVAL;
2381                 type = le32_to_cpu(d->dwPropertyDataType);
2382                 if (type < USB_EXT_PROP_UNICODE ||
2383                     type > USB_EXT_PROP_UNICODE_MULTI) {
2384                         pr_vdebug("unsupported os descriptor property type: %d",
2385                                   type);
2386                         return -EINVAL;
2387                 }
2388                 pnl = le16_to_cpu(d->wPropertyNameLength);
2389                 if (length < 14 + pnl) {
2390                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2391                                   length, pnl, type);
2392                         return -EINVAL;
2393                 }
2394                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2395                 if (length != 14 + pnl + pdl) {
2396                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2397                                   length, pnl, pdl, type);
2398                         return -EINVAL;
2399                 }
2400                 ++ffs->ms_os_descs_ext_prop_count;
2401                 /* property name reported to the host as "WCHAR"s */
2402                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2403                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2404         }
2405                 break;
2406         default:
2407                 pr_vdebug("unknown descriptor: %d\n", type);
2408                 return -EINVAL;
2409         }
2410         return length;
2411 }
2412
2413 static int __ffs_data_got_descs(struct ffs_data *ffs,
2414                                 char *const _data, size_t len)
2415 {
2416         char *data = _data, *raw_descs;
2417         unsigned os_descs_count = 0, counts[3], flags;
2418         int ret = -EINVAL, i;
2419         struct ffs_desc_helper helper;
2420
2421         if (get_unaligned_le32(data + 4) != len)
2422                 goto error;
2423
2424         switch (get_unaligned_le32(data)) {
2425         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2426                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2427                 data += 8;
2428                 len  -= 8;
2429                 break;
2430         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2431                 flags = get_unaligned_le32(data + 8);
2432                 ffs->user_flags = flags;
2433                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2434                               FUNCTIONFS_HAS_HS_DESC |
2435                               FUNCTIONFS_HAS_SS_DESC |
2436                               FUNCTIONFS_HAS_MS_OS_DESC |
2437                               FUNCTIONFS_VIRTUAL_ADDR |
2438                               FUNCTIONFS_EVENTFD |
2439                               FUNCTIONFS_ALL_CTRL_RECIP |
2440                               FUNCTIONFS_CONFIG0_SETUP)) {
2441                         ret = -ENOSYS;
2442                         goto error;
2443                 }
2444                 data += 12;
2445                 len  -= 12;
2446                 break;
2447         default:
2448                 goto error;
2449         }
2450
2451         if (flags & FUNCTIONFS_EVENTFD) {
2452                 if (len < 4)
2453                         goto error;
2454                 ffs->ffs_eventfd =
2455                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2456                 if (IS_ERR(ffs->ffs_eventfd)) {
2457                         ret = PTR_ERR(ffs->ffs_eventfd);
2458                         ffs->ffs_eventfd = NULL;
2459                         goto error;
2460                 }
2461                 data += 4;
2462                 len  -= 4;
2463         }
2464
2465         /* Read fs_count, hs_count and ss_count (if present) */
2466         for (i = 0; i < 3; ++i) {
2467                 if (!(flags & (1 << i))) {
2468                         counts[i] = 0;
2469                 } else if (len < 4) {
2470                         goto error;
2471                 } else {
2472                         counts[i] = get_unaligned_le32(data);
2473                         data += 4;
2474                         len  -= 4;
2475                 }
2476         }
2477         if (flags & (1 << i)) {
2478                 if (len < 4) {
2479                         goto error;
2480                 }
2481                 os_descs_count = get_unaligned_le32(data);
2482                 data += 4;
2483                 len -= 4;
2484         }
2485
2486         /* Read descriptors */
2487         raw_descs = data;
2488         helper.ffs = ffs;
2489         for (i = 0; i < 3; ++i) {
2490                 if (!counts[i])
2491                         continue;
2492                 helper.interfaces_count = 0;
2493                 helper.eps_count = 0;
2494                 ret = ffs_do_descs(counts[i], data, len,
2495                                    __ffs_data_do_entity, &helper);
2496                 if (ret < 0)
2497                         goto error;
2498                 if (!ffs->eps_count && !ffs->interfaces_count) {
2499                         ffs->eps_count = helper.eps_count;
2500                         ffs->interfaces_count = helper.interfaces_count;
2501                 } else {
2502                         if (ffs->eps_count != helper.eps_count) {
2503                                 ret = -EINVAL;
2504                                 goto error;
2505                         }
2506                         if (ffs->interfaces_count != helper.interfaces_count) {
2507                                 ret = -EINVAL;
2508                                 goto error;
2509                         }
2510                 }
2511                 data += ret;
2512                 len  -= ret;
2513         }
2514         if (os_descs_count) {
2515                 ret = ffs_do_os_descs(os_descs_count, data, len,
2516                                       __ffs_data_do_os_desc, ffs);
2517                 if (ret < 0)
2518                         goto error;
2519                 data += ret;
2520                 len -= ret;
2521         }
2522
2523         if (raw_descs == data || len) {
2524                 ret = -EINVAL;
2525                 goto error;
2526         }
2527
2528         ffs->raw_descs_data     = _data;
2529         ffs->raw_descs          = raw_descs;
2530         ffs->raw_descs_length   = data - raw_descs;
2531         ffs->fs_descs_count     = counts[0];
2532         ffs->hs_descs_count     = counts[1];
2533         ffs->ss_descs_count     = counts[2];
2534         ffs->ms_os_descs_count  = os_descs_count;
2535
2536         return 0;
2537
2538 error:
2539         kfree(_data);
2540         return ret;
2541 }
2542
2543 static int __ffs_data_got_strings(struct ffs_data *ffs,
2544                                   char *const _data, size_t len)
2545 {
2546         u32 str_count, needed_count, lang_count;
2547         struct usb_gadget_strings **stringtabs, *t;
2548         const char *data = _data;
2549         struct usb_string *s;
2550
2551         if (len < 16 ||
2552             get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2553             get_unaligned_le32(data + 4) != len)
2554                 goto error;
2555         str_count  = get_unaligned_le32(data + 8);
2556         lang_count = get_unaligned_le32(data + 12);
2557
2558         /* if one is zero the other must be zero */
2559         if (!str_count != !lang_count)
2560                 goto error;
2561
2562         /* Do we have at least as many strings as descriptors need? */
2563         needed_count = ffs->strings_count;
2564         if (str_count < needed_count)
2565                 goto error;
2566
2567         /*
2568          * If we don't need any strings just return and free all
2569          * memory.
2570          */
2571         if (!needed_count) {
2572                 kfree(_data);
2573                 return 0;
2574         }
2575
2576         /* Allocate everything in one chunk so there's less maintenance. */
2577         {
2578                 unsigned i = 0;
2579                 vla_group(d);
2580                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2581                         size_add(lang_count, 1));
2582                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2583                 vla_item(d, struct usb_string, strings,
2584                         size_mul(lang_count, (needed_count + 1)));
2585
2586                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2587
2588                 if (!vlabuf) {
2589                         kfree(_data);
2590                         return -ENOMEM;
2591                 }
2592
2593                 /* Initialize the VLA pointers */
2594                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2595                 t = vla_ptr(vlabuf, d, stringtab);
2596                 i = lang_count;
2597                 do {
2598                         *stringtabs++ = t++;
2599                 } while (--i);
2600                 *stringtabs = NULL;
2601
2602                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2603                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2604                 t = vla_ptr(vlabuf, d, stringtab);
2605                 s = vla_ptr(vlabuf, d, strings);
2606         }
2607
2608         /* For each language */
2609         data += 16;
2610         len -= 16;
2611
2612         do { /* lang_count > 0 so we can use do-while */
2613                 unsigned needed = needed_count;
2614                 u32 str_per_lang = str_count;
2615
2616                 if (len < 3)
2617                         goto error_free;
2618                 t->language = get_unaligned_le16(data);
2619                 t->strings  = s;
2620                 ++t;
2621
2622                 data += 2;
2623                 len -= 2;
2624
2625                 /* For each string */
2626                 do { /* str_count > 0 so we can use do-while */
2627                         size_t length = strnlen(data, len);
2628
2629                         if (length == len)
2630                                 goto error_free;
2631
2632                         /*
2633                          * User may provide more strings then we need,
2634                          * if that's the case we simply ignore the
2635                          * rest
2636                          */
2637                         if (needed) {
2638                                 /*
2639                                  * s->id will be set while adding
2640                                  * function to configuration so for
2641                                  * now just leave garbage here.
2642                                  */
2643                                 s->s = data;
2644                                 --needed;
2645                                 ++s;
2646                         }
2647
2648                         data += length + 1;
2649                         len -= length + 1;
2650                 } while (--str_per_lang);
2651
2652                 s->id = 0;   /* terminator */
2653                 s->s = NULL;
2654                 ++s;
2655
2656         } while (--lang_count);
2657
2658         /* Some garbage left? */
2659         if (len)
2660                 goto error_free;
2661
2662         /* Done! */
2663         ffs->stringtabs = stringtabs;
2664         ffs->raw_strings = _data;
2665
2666         return 0;
2667
2668 error_free:
2669         kfree(stringtabs);
2670 error:
2671         kfree(_data);
2672         return -EINVAL;
2673 }
2674
2675
2676 /* Events handling and management *******************************************/
2677
2678 static void __ffs_event_add(struct ffs_data *ffs,
2679                             enum usb_functionfs_event_type type)
2680 {
2681         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2682         int neg = 0;
2683
2684         /*
2685          * Abort any unhandled setup
2686          *
2687          * We do not need to worry about some cmpxchg() changing value
2688          * of ffs->setup_state without holding the lock because when
2689          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2690          * the source does nothing.
2691          */
2692         if (ffs->setup_state == FFS_SETUP_PENDING)
2693                 ffs->setup_state = FFS_SETUP_CANCELLED;
2694
2695         /*
2696          * Logic of this function guarantees that there are at most four pending
2697          * evens on ffs->ev.types queue.  This is important because the queue
2698          * has space for four elements only and __ffs_ep0_read_events function
2699          * depends on that limit as well.  If more event types are added, those
2700          * limits have to be revisited or guaranteed to still hold.
2701          */
2702         switch (type) {
2703         case FUNCTIONFS_RESUME:
2704                 rem_type2 = FUNCTIONFS_SUSPEND;
2705                 fallthrough;
2706         case FUNCTIONFS_SUSPEND:
2707         case FUNCTIONFS_SETUP:
2708                 rem_type1 = type;
2709                 /* Discard all similar events */
2710                 break;
2711
2712         case FUNCTIONFS_BIND:
2713         case FUNCTIONFS_UNBIND:
2714         case FUNCTIONFS_DISABLE:
2715         case FUNCTIONFS_ENABLE:
2716                 /* Discard everything other then power management. */
2717                 rem_type1 = FUNCTIONFS_SUSPEND;
2718                 rem_type2 = FUNCTIONFS_RESUME;
2719                 neg = 1;
2720                 break;
2721
2722         default:
2723                 WARN(1, "%d: unknown event, this should not happen\n", type);
2724                 return;
2725         }
2726
2727         {
2728                 u8 *ev  = ffs->ev.types, *out = ev;
2729                 unsigned n = ffs->ev.count;
2730                 for (; n; --n, ++ev)
2731                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2732                                 *out++ = *ev;
2733                         else
2734                                 pr_vdebug("purging event %d\n", *ev);
2735                 ffs->ev.count = out - ffs->ev.types;
2736         }
2737
2738         pr_vdebug("adding event %d\n", type);
2739         ffs->ev.types[ffs->ev.count++] = type;
2740         wake_up_locked(&ffs->ev.waitq);
2741         if (ffs->ffs_eventfd)
2742                 eventfd_signal(ffs->ffs_eventfd, 1);
2743 }
2744
2745 static void ffs_event_add(struct ffs_data *ffs,
2746                           enum usb_functionfs_event_type type)
2747 {
2748         unsigned long flags;
2749         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2750         __ffs_event_add(ffs, type);
2751         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2752 }
2753
2754 /* Bind/unbind USB function hooks *******************************************/
2755
2756 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2757 {
2758         int i;
2759
2760         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2761                 if (ffs->eps_addrmap[i] == endpoint_address)
2762                         return i;
2763         return -ENOENT;
2764 }
2765
2766 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2767                                     struct usb_descriptor_header *desc,
2768                                     void *priv)
2769 {
2770         struct usb_endpoint_descriptor *ds = (void *)desc;
2771         struct ffs_function *func = priv;
2772         struct ffs_ep *ffs_ep;
2773         unsigned ep_desc_id;
2774         int idx;
2775         static const char *speed_names[] = { "full", "high", "super" };
2776
2777         if (type != FFS_DESCRIPTOR)
2778                 return 0;
2779
2780         /*
2781          * If ss_descriptors is not NULL, we are reading super speed
2782          * descriptors; if hs_descriptors is not NULL, we are reading high
2783          * speed descriptors; otherwise, we are reading full speed
2784          * descriptors.
2785          */
2786         if (func->function.ss_descriptors) {
2787                 ep_desc_id = 2;
2788                 func->function.ss_descriptors[(long)valuep] = desc;
2789         } else if (func->function.hs_descriptors) {
2790                 ep_desc_id = 1;
2791                 func->function.hs_descriptors[(long)valuep] = desc;
2792         } else {
2793                 ep_desc_id = 0;
2794                 func->function.fs_descriptors[(long)valuep]    = desc;
2795         }
2796
2797         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2798                 return 0;
2799
2800         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2801         if (idx < 0)
2802                 return idx;
2803
2804         ffs_ep = func->eps + idx;
2805
2806         if (ffs_ep->descs[ep_desc_id]) {
2807                 pr_err("two %sspeed descriptors for EP %d\n",
2808                           speed_names[ep_desc_id],
2809                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2810                 return -EINVAL;
2811         }
2812         ffs_ep->descs[ep_desc_id] = ds;
2813
2814         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2815         if (ffs_ep->ep) {
2816                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2817                 if (!ds->wMaxPacketSize)
2818                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2819         } else {
2820                 struct usb_request *req;
2821                 struct usb_ep *ep;
2822                 u8 bEndpointAddress;
2823                 u16 wMaxPacketSize;
2824
2825                 /*
2826                  * We back up bEndpointAddress because autoconfig overwrites
2827                  * it with physical endpoint address.
2828                  */
2829                 bEndpointAddress = ds->bEndpointAddress;
2830                 /*
2831                  * We back up wMaxPacketSize because autoconfig treats
2832                  * endpoint descriptors as if they were full speed.
2833                  */
2834                 wMaxPacketSize = ds->wMaxPacketSize;
2835                 pr_vdebug("autoconfig\n");
2836                 ep = usb_ep_autoconfig(func->gadget, ds);
2837                 if (!ep)
2838                         return -ENOTSUPP;
2839                 ep->driver_data = func->eps + idx;
2840
2841                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2842                 if (!req)
2843                         return -ENOMEM;
2844
2845                 ffs_ep->ep  = ep;
2846                 ffs_ep->req = req;
2847                 func->eps_revmap[ds->bEndpointAddress &
2848                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2849                 /*
2850                  * If we use virtual address mapping, we restore
2851                  * original bEndpointAddress value.
2852                  */
2853                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2854                         ds->bEndpointAddress = bEndpointAddress;
2855                 /*
2856                  * Restore wMaxPacketSize which was potentially
2857                  * overwritten by autoconfig.
2858                  */
2859                 ds->wMaxPacketSize = wMaxPacketSize;
2860         }
2861         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2862
2863         return 0;
2864 }
2865
2866 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2867                                    struct usb_descriptor_header *desc,
2868                                    void *priv)
2869 {
2870         struct ffs_function *func = priv;
2871         unsigned idx;
2872         u8 newValue;
2873
2874         switch (type) {
2875         default:
2876         case FFS_DESCRIPTOR:
2877                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2878                 return 0;
2879
2880         case FFS_INTERFACE:
2881                 idx = *valuep;
2882                 if (func->interfaces_nums[idx] < 0) {
2883                         int id = usb_interface_id(func->conf, &func->function);
2884                         if (id < 0)
2885                                 return id;
2886                         func->interfaces_nums[idx] = id;
2887                 }
2888                 newValue = func->interfaces_nums[idx];
2889                 break;
2890
2891         case FFS_STRING:
2892                 /* String' IDs are allocated when fsf_data is bound to cdev */
2893                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2894                 break;
2895
2896         case FFS_ENDPOINT:
2897                 /*
2898                  * USB_DT_ENDPOINT are handled in
2899                  * __ffs_func_bind_do_descs().
2900                  */
2901                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2902                         return 0;
2903
2904                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2905                 if (!func->eps[idx].ep)
2906                         return -EINVAL;
2907
2908                 {
2909                         struct usb_endpoint_descriptor **descs;
2910                         descs = func->eps[idx].descs;
2911                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2912                 }
2913                 break;
2914         }
2915
2916         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2917         *valuep = newValue;
2918         return 0;
2919 }
2920
2921 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2922                                       struct usb_os_desc_header *h, void *data,
2923                                       unsigned len, void *priv)
2924 {
2925         struct ffs_function *func = priv;
2926         u8 length = 0;
2927
2928         switch (type) {
2929         case FFS_OS_DESC_EXT_COMPAT: {
2930                 struct usb_ext_compat_desc *desc = data;
2931                 struct usb_os_desc_table *t;
2932
2933                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2934                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2935                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2936                        ARRAY_SIZE(desc->CompatibleID) +
2937                        ARRAY_SIZE(desc->SubCompatibleID));
2938                 length = sizeof(*desc);
2939         }
2940                 break;
2941         case FFS_OS_DESC_EXT_PROP: {
2942                 struct usb_ext_prop_desc *desc = data;
2943                 struct usb_os_desc_table *t;
2944                 struct usb_os_desc_ext_prop *ext_prop;
2945                 char *ext_prop_name;
2946                 char *ext_prop_data;
2947
2948                 t = &func->function.os_desc_table[h->interface];
2949                 t->if_id = func->interfaces_nums[h->interface];
2950
2951                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2952                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2953
2954                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2955                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2956                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
2957                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2958                 length = ext_prop->name_len + ext_prop->data_len + 14;
2959
2960                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2961                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2962                         ext_prop->name_len;
2963
2964                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2965                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2966                         ext_prop->data_len;
2967                 memcpy(ext_prop_data,
2968                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2969                        ext_prop->data_len);
2970                 /* unicode data reported to the host as "WCHAR"s */
2971                 switch (ext_prop->type) {
2972                 case USB_EXT_PROP_UNICODE:
2973                 case USB_EXT_PROP_UNICODE_ENV:
2974                 case USB_EXT_PROP_UNICODE_LINK:
2975                 case USB_EXT_PROP_UNICODE_MULTI:
2976                         ext_prop->data_len *= 2;
2977                         break;
2978                 }
2979                 ext_prop->data = ext_prop_data;
2980
2981                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2982                        ext_prop->name_len);
2983                 /* property name reported to the host as "WCHAR"s */
2984                 ext_prop->name_len *= 2;
2985                 ext_prop->name = ext_prop_name;
2986
2987                 t->os_desc->ext_prop_len +=
2988                         ext_prop->name_len + ext_prop->data_len + 14;
2989                 ++t->os_desc->ext_prop_count;
2990                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2991         }
2992                 break;
2993         default:
2994                 pr_vdebug("unknown descriptor: %d\n", type);
2995         }
2996
2997         return length;
2998 }
2999
3000 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3001                                                 struct usb_configuration *c)
3002 {
3003         struct ffs_function *func = ffs_func_from_usb(f);
3004         struct f_fs_opts *ffs_opts =
3005                 container_of(f->fi, struct f_fs_opts, func_inst);
3006         struct ffs_data *ffs_data;
3007         int ret;
3008
3009         /*
3010          * Legacy gadget triggers binding in functionfs_ready_callback,
3011          * which already uses locking; taking the same lock here would
3012          * cause a deadlock.
3013          *
3014          * Configfs-enabled gadgets however do need ffs_dev_lock.
3015          */
3016         if (!ffs_opts->no_configfs)
3017                 ffs_dev_lock();
3018         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3019         ffs_data = ffs_opts->dev->ffs_data;
3020         if (!ffs_opts->no_configfs)
3021                 ffs_dev_unlock();
3022         if (ret)
3023                 return ERR_PTR(ret);
3024
3025         func->ffs = ffs_data;
3026         func->conf = c;
3027         func->gadget = c->cdev->gadget;
3028
3029         /*
3030          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3031          * configurations are bound in sequence with list_for_each_entry,
3032          * in each configuration its functions are bound in sequence
3033          * with list_for_each_entry, so we assume no race condition
3034          * with regard to ffs_opts->bound access
3035          */
3036         if (!ffs_opts->refcnt) {
3037                 ret = functionfs_bind(func->ffs, c->cdev);
3038                 if (ret)
3039                         return ERR_PTR(ret);
3040         }
3041         ffs_opts->refcnt++;
3042         func->function.strings = func->ffs->stringtabs;
3043
3044         return ffs_opts;
3045 }
3046
3047 static int _ffs_func_bind(struct usb_configuration *c,
3048                           struct usb_function *f)
3049 {
3050         struct ffs_function *func = ffs_func_from_usb(f);
3051         struct ffs_data *ffs = func->ffs;
3052
3053         const int full = !!func->ffs->fs_descs_count;
3054         const int high = !!func->ffs->hs_descs_count;
3055         const int super = !!func->ffs->ss_descs_count;
3056
3057         int fs_len, hs_len, ss_len, ret, i;
3058         struct ffs_ep *eps_ptr;
3059
3060         /* Make it a single chunk, less management later on */
3061         vla_group(d);
3062         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3063         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3064                 full ? ffs->fs_descs_count + 1 : 0);
3065         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3066                 high ? ffs->hs_descs_count + 1 : 0);
3067         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3068                 super ? ffs->ss_descs_count + 1 : 0);
3069         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3070         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3071                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3072         vla_item_with_sz(d, char[16], ext_compat,
3073                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3074         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3075                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3076         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3077                          ffs->ms_os_descs_ext_prop_count);
3078         vla_item_with_sz(d, char, ext_prop_name,
3079                          ffs->ms_os_descs_ext_prop_name_len);
3080         vla_item_with_sz(d, char, ext_prop_data,
3081                          ffs->ms_os_descs_ext_prop_data_len);
3082         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3083         char *vlabuf;
3084
3085         /* Has descriptors only for speeds gadget does not support */
3086         if (!(full | high | super))
3087                 return -ENOTSUPP;
3088
3089         /* Allocate a single chunk, less management later on */
3090         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3091         if (!vlabuf)
3092                 return -ENOMEM;
3093
3094         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3095         ffs->ms_os_descs_ext_prop_name_avail =
3096                 vla_ptr(vlabuf, d, ext_prop_name);
3097         ffs->ms_os_descs_ext_prop_data_avail =
3098                 vla_ptr(vlabuf, d, ext_prop_data);
3099
3100         /* Copy descriptors  */
3101         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3102                ffs->raw_descs_length);
3103
3104         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3105         eps_ptr = vla_ptr(vlabuf, d, eps);
3106         for (i = 0; i < ffs->eps_count; i++)
3107                 eps_ptr[i].num = -1;
3108
3109         /* Save pointers
3110          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3111         */
3112         func->eps             = vla_ptr(vlabuf, d, eps);
3113         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3114
3115         /*
3116          * Go through all the endpoint descriptors and allocate
3117          * endpoints first, so that later we can rewrite the endpoint
3118          * numbers without worrying that it may be described later on.
3119          */
3120         if (full) {
3121                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3122                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3123                                       vla_ptr(vlabuf, d, raw_descs),
3124                                       d_raw_descs__sz,
3125                                       __ffs_func_bind_do_descs, func);
3126                 if (fs_len < 0) {
3127                         ret = fs_len;
3128                         goto error;
3129                 }
3130         } else {
3131                 fs_len = 0;
3132         }
3133
3134         if (high) {
3135                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3136                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3137                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3138                                       d_raw_descs__sz - fs_len,
3139                                       __ffs_func_bind_do_descs, func);
3140                 if (hs_len < 0) {
3141                         ret = hs_len;
3142                         goto error;
3143                 }
3144         } else {
3145                 hs_len = 0;
3146         }
3147
3148         if (super) {
3149                 func->function.ss_descriptors = func->function.ssp_descriptors =
3150                         vla_ptr(vlabuf, d, ss_descs);
3151                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3152                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3153                                 d_raw_descs__sz - fs_len - hs_len,
3154                                 __ffs_func_bind_do_descs, func);
3155                 if (ss_len < 0) {
3156                         ret = ss_len;
3157                         goto error;
3158                 }
3159         } else {
3160                 ss_len = 0;
3161         }
3162
3163         /*
3164          * Now handle interface numbers allocation and interface and
3165          * endpoint numbers rewriting.  We can do that in one go
3166          * now.
3167          */
3168         ret = ffs_do_descs(ffs->fs_descs_count +
3169                            (high ? ffs->hs_descs_count : 0) +
3170                            (super ? ffs->ss_descs_count : 0),
3171                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3172                            __ffs_func_bind_do_nums, func);
3173         if (ret < 0)
3174                 goto error;
3175
3176         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3177         if (c->cdev->use_os_string) {
3178                 for (i = 0; i < ffs->interfaces_count; ++i) {
3179                         struct usb_os_desc *desc;
3180
3181                         desc = func->function.os_desc_table[i].os_desc =
3182                                 vla_ptr(vlabuf, d, os_desc) +
3183                                 i * sizeof(struct usb_os_desc);
3184                         desc->ext_compat_id =
3185                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3186                         INIT_LIST_HEAD(&desc->ext_prop);
3187                 }
3188                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3189                                       vla_ptr(vlabuf, d, raw_descs) +
3190                                       fs_len + hs_len + ss_len,
3191                                       d_raw_descs__sz - fs_len - hs_len -
3192                                       ss_len,
3193                                       __ffs_func_bind_do_os_desc, func);
3194                 if (ret < 0)
3195                         goto error;
3196         }
3197         func->function.os_desc_n =
3198                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3199
3200         /* And we're done */
3201         ffs_event_add(ffs, FUNCTIONFS_BIND);
3202         return 0;
3203
3204 error:
3205         /* XXX Do we need to release all claimed endpoints here? */
3206         return ret;
3207 }
3208
3209 static int ffs_func_bind(struct usb_configuration *c,
3210                          struct usb_function *f)
3211 {
3212         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3213         struct ffs_function *func = ffs_func_from_usb(f);
3214         int ret;
3215
3216         if (IS_ERR(ffs_opts))
3217                 return PTR_ERR(ffs_opts);
3218
3219         ret = _ffs_func_bind(c, f);
3220         if (ret && !--ffs_opts->refcnt)
3221                 functionfs_unbind(func->ffs);
3222
3223         return ret;
3224 }
3225
3226
3227 /* Other USB function hooks *************************************************/
3228
3229 static void ffs_reset_work(struct work_struct *work)
3230 {
3231         struct ffs_data *ffs = container_of(work,
3232                 struct ffs_data, reset_work);
3233         ffs_data_reset(ffs);
3234 }
3235
3236 static int ffs_func_set_alt(struct usb_function *f,
3237                             unsigned interface, unsigned alt)
3238 {
3239         struct ffs_function *func = ffs_func_from_usb(f);
3240         struct ffs_data *ffs = func->ffs;
3241         int ret = 0, intf;
3242
3243         if (alt != (unsigned)-1) {
3244                 intf = ffs_func_revmap_intf(func, interface);
3245                 if (intf < 0)
3246                         return intf;
3247         }
3248
3249         if (ffs->func)
3250                 ffs_func_eps_disable(ffs->func);
3251
3252         if (ffs->state == FFS_DEACTIVATED) {
3253                 ffs->state = FFS_CLOSING;
3254                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3255                 schedule_work(&ffs->reset_work);
3256                 return -ENODEV;
3257         }
3258
3259         if (ffs->state != FFS_ACTIVE)
3260                 return -ENODEV;
3261
3262         if (alt == (unsigned)-1) {
3263                 ffs->func = NULL;
3264                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3265                 return 0;
3266         }
3267
3268         ffs->func = func;
3269         ret = ffs_func_eps_enable(func);
3270         if (ret >= 0)
3271                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3272         return ret;
3273 }
3274
3275 static void ffs_func_disable(struct usb_function *f)
3276 {
3277         ffs_func_set_alt(f, 0, (unsigned)-1);
3278 }
3279
3280 static int ffs_func_setup(struct usb_function *f,
3281                           const struct usb_ctrlrequest *creq)
3282 {
3283         struct ffs_function *func = ffs_func_from_usb(f);
3284         struct ffs_data *ffs = func->ffs;
3285         unsigned long flags;
3286         int ret;
3287
3288         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3289         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3290         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3291         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3292         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3293
3294         /*
3295          * Most requests directed to interface go through here
3296          * (notable exceptions are set/get interface) so we need to
3297          * handle them.  All other either handled by composite or
3298          * passed to usb_configuration->setup() (if one is set).  No
3299          * matter, we will handle requests directed to endpoint here
3300          * as well (as it's straightforward).  Other request recipient
3301          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3302          * is being used.
3303          */
3304         if (ffs->state != FFS_ACTIVE)
3305                 return -ENODEV;
3306
3307         switch (creq->bRequestType & USB_RECIP_MASK) {
3308         case USB_RECIP_INTERFACE:
3309                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3310                 if (ret < 0)
3311                         return ret;
3312                 break;
3313
3314         case USB_RECIP_ENDPOINT:
3315                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3316                 if (ret < 0)
3317                         return ret;
3318                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3319                         ret = func->ffs->eps_addrmap[ret];
3320                 break;
3321
3322         default:
3323                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3324                         ret = le16_to_cpu(creq->wIndex);
3325                 else
3326                         return -EOPNOTSUPP;
3327         }
3328
3329         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3330         ffs->ev.setup = *creq;
3331         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3332         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3333         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3334
3335         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3336 }
3337
3338 static bool ffs_func_req_match(struct usb_function *f,
3339                                const struct usb_ctrlrequest *creq,
3340                                bool config0)
3341 {
3342         struct ffs_function *func = ffs_func_from_usb(f);
3343
3344         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3345                 return false;
3346
3347         switch (creq->bRequestType & USB_RECIP_MASK) {
3348         case USB_RECIP_INTERFACE:
3349                 return (ffs_func_revmap_intf(func,
3350                                              le16_to_cpu(creq->wIndex)) >= 0);
3351         case USB_RECIP_ENDPOINT:
3352                 return (ffs_func_revmap_ep(func,
3353                                            le16_to_cpu(creq->wIndex)) >= 0);
3354         default:
3355                 return (bool) (func->ffs->user_flags &
3356                                FUNCTIONFS_ALL_CTRL_RECIP);
3357         }
3358 }
3359
3360 static void ffs_func_suspend(struct usb_function *f)
3361 {
3362         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3363 }
3364
3365 static void ffs_func_resume(struct usb_function *f)
3366 {
3367         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3368 }
3369
3370
3371 /* Endpoint and interface numbers reverse mapping ***************************/
3372
3373 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3374 {
3375         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3376         return num ? num : -EDOM;
3377 }
3378
3379 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3380 {
3381         short *nums = func->interfaces_nums;
3382         unsigned count = func->ffs->interfaces_count;
3383
3384         for (; count; --count, ++nums) {
3385                 if (*nums >= 0 && *nums == intf)
3386                         return nums - func->interfaces_nums;
3387         }
3388
3389         return -EDOM;
3390 }
3391
3392
3393 /* Devices management *******************************************************/
3394
3395 static LIST_HEAD(ffs_devices);
3396
3397 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3398 {
3399         struct ffs_dev *dev;
3400
3401         if (!name)
3402                 return NULL;
3403
3404         list_for_each_entry(dev, &ffs_devices, entry) {
3405                 if (strcmp(dev->name, name) == 0)
3406                         return dev;
3407         }
3408
3409         return NULL;
3410 }
3411
3412 /*
3413  * ffs_lock must be taken by the caller of this function
3414  */
3415 static struct ffs_dev *_ffs_get_single_dev(void)
3416 {
3417         struct ffs_dev *dev;
3418
3419         if (list_is_singular(&ffs_devices)) {
3420                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3421                 if (dev->single)
3422                         return dev;
3423         }
3424
3425         return NULL;
3426 }
3427
3428 /*
3429  * ffs_lock must be taken by the caller of this function
3430  */
3431 static struct ffs_dev *_ffs_find_dev(const char *name)
3432 {
3433         struct ffs_dev *dev;
3434
3435         dev = _ffs_get_single_dev();
3436         if (dev)
3437                 return dev;
3438
3439         return _ffs_do_find_dev(name);
3440 }
3441
3442 /* Configfs support *********************************************************/
3443
3444 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3445 {
3446         return container_of(to_config_group(item), struct f_fs_opts,
3447                             func_inst.group);
3448 }
3449
3450 static void ffs_attr_release(struct config_item *item)
3451 {
3452         struct f_fs_opts *opts = to_ffs_opts(item);
3453
3454         usb_put_function_instance(&opts->func_inst);
3455 }
3456
3457 static struct configfs_item_operations ffs_item_ops = {
3458         .release        = ffs_attr_release,
3459 };
3460
3461 static const struct config_item_type ffs_func_type = {
3462         .ct_item_ops    = &ffs_item_ops,
3463         .ct_owner       = THIS_MODULE,
3464 };
3465
3466
3467 /* Function registration interface ******************************************/
3468
3469 static void ffs_free_inst(struct usb_function_instance *f)
3470 {
3471         struct f_fs_opts *opts;
3472
3473         opts = to_f_fs_opts(f);
3474         ffs_release_dev(opts->dev);
3475         ffs_dev_lock();
3476         _ffs_free_dev(opts->dev);
3477         ffs_dev_unlock();
3478         kfree(opts);
3479 }
3480
3481 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3482 {
3483         if (strlen(name) >= sizeof_field(struct ffs_dev, name))
3484                 return -ENAMETOOLONG;
3485         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3486 }
3487
3488 static struct usb_function_instance *ffs_alloc_inst(void)
3489 {
3490         struct f_fs_opts *opts;
3491         struct ffs_dev *dev;
3492
3493         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3494         if (!opts)
3495                 return ERR_PTR(-ENOMEM);
3496
3497         opts->func_inst.set_inst_name = ffs_set_inst_name;
3498         opts->func_inst.free_func_inst = ffs_free_inst;
3499         ffs_dev_lock();
3500         dev = _ffs_alloc_dev();
3501         ffs_dev_unlock();
3502         if (IS_ERR(dev)) {
3503                 kfree(opts);
3504                 return ERR_CAST(dev);
3505         }
3506         opts->dev = dev;
3507         dev->opts = opts;
3508
3509         config_group_init_type_name(&opts->func_inst.group, "",
3510                                     &ffs_func_type);
3511         return &opts->func_inst;
3512 }
3513
3514 static void ffs_free(struct usb_function *f)
3515 {
3516         kfree(ffs_func_from_usb(f));
3517 }
3518
3519 static void ffs_func_unbind(struct usb_configuration *c,
3520                             struct usb_function *f)
3521 {
3522         struct ffs_function *func = ffs_func_from_usb(f);
3523         struct ffs_data *ffs = func->ffs;
3524         struct f_fs_opts *opts =
3525                 container_of(f->fi, struct f_fs_opts, func_inst);
3526         struct ffs_ep *ep = func->eps;
3527         unsigned count = ffs->eps_count;
3528         unsigned long flags;
3529
3530         if (ffs->func == func) {
3531                 ffs_func_eps_disable(func);
3532                 ffs->func = NULL;
3533         }
3534
3535         /* Drain any pending AIO completions */
3536         drain_workqueue(ffs->io_completion_wq);
3537
3538         if (!--opts->refcnt)
3539                 functionfs_unbind(ffs);
3540
3541         /* cleanup after autoconfig */
3542         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3543         while (count--) {
3544                 if (ep->ep && ep->req)
3545                         usb_ep_free_request(ep->ep, ep->req);
3546                 ep->req = NULL;
3547                 ++ep;
3548         }
3549         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3550         kfree(func->eps);
3551         func->eps = NULL;
3552         /*
3553          * eps, descriptors and interfaces_nums are allocated in the
3554          * same chunk so only one free is required.
3555          */
3556         func->function.fs_descriptors = NULL;
3557         func->function.hs_descriptors = NULL;
3558         func->function.ss_descriptors = NULL;
3559         func->function.ssp_descriptors = NULL;
3560         func->interfaces_nums = NULL;
3561
3562         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3563 }
3564
3565 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3566 {
3567         struct ffs_function *func;
3568
3569         func = kzalloc(sizeof(*func), GFP_KERNEL);
3570         if (!func)
3571                 return ERR_PTR(-ENOMEM);
3572
3573         func->function.name    = "Function FS Gadget";
3574
3575         func->function.bind    = ffs_func_bind;
3576         func->function.unbind  = ffs_func_unbind;
3577         func->function.set_alt = ffs_func_set_alt;
3578         func->function.disable = ffs_func_disable;
3579         func->function.setup   = ffs_func_setup;
3580         func->function.req_match = ffs_func_req_match;
3581         func->function.suspend = ffs_func_suspend;
3582         func->function.resume  = ffs_func_resume;
3583         func->function.free_func = ffs_free;
3584
3585         return &func->function;
3586 }
3587
3588 /*
3589  * ffs_lock must be taken by the caller of this function
3590  */
3591 static struct ffs_dev *_ffs_alloc_dev(void)
3592 {
3593         struct ffs_dev *dev;
3594         int ret;
3595
3596         if (_ffs_get_single_dev())
3597                         return ERR_PTR(-EBUSY);
3598
3599         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3600         if (!dev)
3601                 return ERR_PTR(-ENOMEM);
3602
3603         if (list_empty(&ffs_devices)) {
3604                 ret = functionfs_init();
3605                 if (ret) {
3606                         kfree(dev);
3607                         return ERR_PTR(ret);
3608                 }
3609         }
3610
3611         list_add(&dev->entry, &ffs_devices);
3612
3613         return dev;
3614 }
3615
3616 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3617 {
3618         struct ffs_dev *existing;
3619         int ret = 0;
3620
3621         ffs_dev_lock();
3622
3623         existing = _ffs_do_find_dev(name);
3624         if (!existing)
3625                 strscpy(dev->name, name, ARRAY_SIZE(dev->name));
3626         else if (existing != dev)
3627                 ret = -EBUSY;
3628
3629         ffs_dev_unlock();
3630
3631         return ret;
3632 }
3633 EXPORT_SYMBOL_GPL(ffs_name_dev);
3634
3635 int ffs_single_dev(struct ffs_dev *dev)
3636 {
3637         int ret;
3638
3639         ret = 0;
3640         ffs_dev_lock();
3641
3642         if (!list_is_singular(&ffs_devices))
3643                 ret = -EBUSY;
3644         else
3645                 dev->single = true;
3646
3647         ffs_dev_unlock();
3648         return ret;
3649 }
3650 EXPORT_SYMBOL_GPL(ffs_single_dev);
3651
3652 /*
3653  * ffs_lock must be taken by the caller of this function
3654  */
3655 static void _ffs_free_dev(struct ffs_dev *dev)
3656 {
3657         list_del(&dev->entry);
3658
3659         kfree(dev);
3660         if (list_empty(&ffs_devices))
3661                 functionfs_cleanup();
3662 }
3663
3664 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data)
3665 {
3666         int ret = 0;
3667         struct ffs_dev *ffs_dev;
3668
3669         ffs_dev_lock();
3670
3671         ffs_dev = _ffs_find_dev(dev_name);
3672         if (!ffs_dev) {
3673                 ret = -ENOENT;
3674         } else if (ffs_dev->mounted) {
3675                 ret = -EBUSY;
3676         } else if (ffs_dev->ffs_acquire_dev_callback &&
3677                    ffs_dev->ffs_acquire_dev_callback(ffs_dev)) {
3678                 ret = -ENOENT;
3679         } else {
3680                 ffs_dev->mounted = true;
3681                 ffs_dev->ffs_data = ffs_data;
3682                 ffs_data->private_data = ffs_dev;
3683         }
3684
3685         ffs_dev_unlock();
3686         return ret;
3687 }
3688
3689 static void ffs_release_dev(struct ffs_dev *ffs_dev)
3690 {
3691         ffs_dev_lock();
3692
3693         if (ffs_dev && ffs_dev->mounted) {
3694                 ffs_dev->mounted = false;
3695                 if (ffs_dev->ffs_data) {
3696                         ffs_dev->ffs_data->private_data = NULL;
3697                         ffs_dev->ffs_data = NULL;
3698                 }
3699
3700                 if (ffs_dev->ffs_release_dev_callback)
3701                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3702         }
3703
3704         ffs_dev_unlock();
3705 }
3706
3707 static int ffs_ready(struct ffs_data *ffs)
3708 {
3709         struct ffs_dev *ffs_obj;
3710         int ret = 0;
3711
3712         ffs_dev_lock();
3713
3714         ffs_obj = ffs->private_data;
3715         if (!ffs_obj) {
3716                 ret = -EINVAL;
3717                 goto done;
3718         }
3719         if (WARN_ON(ffs_obj->desc_ready)) {
3720                 ret = -EBUSY;
3721                 goto done;
3722         }
3723
3724         ffs_obj->desc_ready = true;
3725
3726         if (ffs_obj->ffs_ready_callback) {
3727                 ret = ffs_obj->ffs_ready_callback(ffs);
3728                 if (ret)
3729                         goto done;
3730         }
3731
3732         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3733 done:
3734         ffs_dev_unlock();
3735         return ret;
3736 }
3737
3738 static void ffs_closed(struct ffs_data *ffs)
3739 {
3740         struct ffs_dev *ffs_obj;
3741         struct f_fs_opts *opts;
3742         struct config_item *ci;
3743
3744         ffs_dev_lock();
3745
3746         ffs_obj = ffs->private_data;
3747         if (!ffs_obj)
3748                 goto done;
3749
3750         ffs_obj->desc_ready = false;
3751
3752         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3753             ffs_obj->ffs_closed_callback)
3754                 ffs_obj->ffs_closed_callback(ffs);
3755
3756         if (ffs_obj->opts)
3757                 opts = ffs_obj->opts;
3758         else
3759                 goto done;
3760
3761         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3762             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3763                 goto done;
3764
3765         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3766         ffs_dev_unlock();
3767
3768         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3769                 unregister_gadget_item(ci);
3770         return;
3771 done:
3772         ffs_dev_unlock();
3773 }
3774
3775 /* Misc helper functions ****************************************************/
3776
3777 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3778 {
3779         return nonblock
3780                 ? mutex_trylock(mutex) ? 0 : -EAGAIN
3781                 : mutex_lock_interruptible(mutex);
3782 }
3783
3784 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3785 {
3786         char *data;
3787
3788         if (!len)
3789                 return NULL;
3790
3791         data = memdup_user(buf, len);
3792         if (IS_ERR(data))
3793                 return data;
3794
3795         pr_vdebug("Buffer from user space:\n");
3796         ffs_dump_mem("", data, len);
3797
3798         return data;
3799 }
3800
3801 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3802 MODULE_LICENSE("GPL");
3803 MODULE_AUTHOR("Michal Nazarewicz");