drivers/usb/gadget/function/f_fs.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_fs.c -- user mode file system API for USB composite function controllers
   4  *
   5  * Copyright (C) 2010 Samsung Electronics
   6  * Author: Michal Nazarewicz <mina86@mina86.com>
   7  *
   8  * Based on inode.c (GadgetFS) which was:
   9  * Copyright (C) 2003-2004 David Brownell
  10  * Copyright (C) 2003 Agilent Technologies
  11  */
  12
  13
  14 /* #define DEBUG */
  15 /* #define VERBOSE_DEBUG */
  16
  17 #include <linux/blkdev.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/export.h>
  20 #include <linux/fs_parser.h>
  21 #include <linux/hid.h>
  22 #include <linux/mm.h>
  23 #include <linux/module.h>
  24 #include <linux/scatterlist.h>
  25 #include <linux/sched/signal.h>
  26 #include <linux/uio.h>
  27 #include <linux/vmalloc.h>
  28 #include <asm/unaligned.h>
  29
  30 #include <linux/usb/ccid.h>
  31 #include <linux/usb/composite.h>
  32 #include <linux/usb/functionfs.h>
  33
  34 #include <linux/aio.h>
  35 #include <linux/kthread.h>
  36 #include <linux/poll.h>
  37 #include <linux/eventfd.h>
  38
  39 #include "u_fs.h"
  40 #include "u_f.h"
  41 #include "u_os_desc.h"
  42 #include "configfs.h"
  43
  44 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  45
  46 /* Reference counter handling */
  47 static void ffs_data_get(struct ffs_data *ffs);
  48 static void ffs_data_put(struct ffs_data *ffs);
  49 /* Creates new ffs_data object. */
  50 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  51         __attribute__((malloc));
  52
  53 /* Opened counter handling. */
  54 static void ffs_data_opened(struct ffs_data *ffs);
  55 static void ffs_data_closed(struct ffs_data *ffs);
  56
  57 /* Called with ffs->mutex held; take over ownership of data. */
  58 static int __must_check
  59 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  60 static int __must_check
  61 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  62
  63
  64 /* The function structure ***************************************************/
  65
  66 struct ffs_ep;
  67
  68 struct ffs_function {
  69         struct usb_configuration        *conf;
  70         struct usb_gadget               *gadget;
  71         struct ffs_data                 *ffs;
  72
  73         struct ffs_ep                   *eps;
  74         u8                              eps_revmap[16];
  75         short                           *interfaces_nums;
  76
  77         struct usb_function             function;
  78 };
  79
  80
  81 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  82 {
  83         return container_of(f, struct ffs_function, function);
  84 }
  85
  86
  87 static inline enum ffs_setup_state
  88 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  89 {
  90         return (enum ffs_setup_state)
  91                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  92 }
  93
  94
  95 static void ffs_func_eps_disable(struct ffs_function *func);
  96 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  97
  98 static int ffs_func_bind(struct usb_configuration *,
  99                          struct usb_function *);
 100 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 101 static void ffs_func_disable(struct usb_function *);
 102 static int ffs_func_setup(struct usb_function *,
 103                           const struct usb_ctrlrequest *);
 104 static bool ffs_func_req_match(struct usb_function *,
 105                                const struct usb_ctrlrequest *,
 106                                bool config0);
 107 static void ffs_func_suspend(struct usb_function *);
 108 static void ffs_func_resume(struct usb_function *);
 109
 110
 111 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 112 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 113
 114
 115 /* The endpoints structures *************************************************/
 116
 117 struct ffs_ep {
 118         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 119         struct usb_request              *req;   /* P: epfile->mutex */
 120
 121         /* [0]: full speed, [1]: high speed, [2]: super speed */
 122         struct usb_endpoint_descriptor  *descs[3];
 123
 124         u8                              num;
 125
 126         int                             status; /* P: epfile->mutex */
 127 };
 128
 129 struct ffs_epfile {
 130         /* Protects ep->ep and ep->req. */
 131         struct mutex                    mutex;
 132
 133         struct ffs_data                 *ffs;
 134         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 135
 136         struct dentry                   *dentry;
 137
 138         /*
 139          * Buffer for holding data from partial reads which may happen since
 140          * we’re rounding user read requests to a multiple of a max packet size.
 141          *
 142          * The pointer is initialised with NULL value and may be set by
 143          * __ffs_epfile_read_data function to point to a temporary buffer.
 144          *
 145          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 146          * data from said buffer and eventually free it.  Importantly, while the
 147          * function is using the buffer, it sets the pointer to NULL.  This is
 148          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 149          * can never run concurrently (they are synchronised by epfile->mutex)
 150          * so the latter will not assign a new value to the pointer.
 151          *
 152          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 153          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 154          * value is crux of the synchronisation between ffs_func_eps_disable and
 155          * __ffs_epfile_read_data.
 156          *
 157          * Once __ffs_epfile_read_data is about to finish it will try to set the
 158          * pointer back to its old value (as described above), but seeing as the
 159          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 160          * the buffer.
 161          *
 162          * == State transitions ==
 163          *
 164          * • ptr == NULL:  (initial state)
 165          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 166          *   ◦ __ffs_epfile_read_buffered:    nop
 167          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 168          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 169          * • ptr == DROP:
 170          *   ◦ __ffs_epfile_read_buffer_free: nop
 171          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 172          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 173          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 174          * • ptr == buf:
 175          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 176          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 177          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 178          *                                    is always called first
 179          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 180          * • ptr == NULL and reading:
 181          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 182          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 183          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 184          *   ◦ reading finishes and …
 185          *     … all data read:               free buf, go to ptr == NULL
 186          *     … otherwise:                   go to ptr == buf and reading
 187          * • ptr == DROP and reading:
 188          *   ◦ __ffs_epfile_read_buffer_free: nop
 189          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 190          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 191          *   ◦ reading finishes:              free buf, go to ptr == DROP
 192          */
 193         struct ffs_buffer               *read_buffer;
 194 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 195
 196         char                            name[5];
 197
 198         unsigned char                   in;     /* P: ffs->eps_lock */
 199         unsigned char                   isoc;   /* P: ffs->eps_lock */
 200
 201         unsigned char                   _pad;
 202 };
 203
 204 struct ffs_buffer {
 205         size_t length;
 206         char *data;
 207         char storage[];
 208 };
 209
 210 /*  ffs_io_data structure ***************************************************/
 211
 212 struct ffs_io_data {
 213         bool aio;
 214         bool read;
 215
 216         struct kiocb *kiocb;
 217         struct iov_iter data;
 218         const void *to_free;
 219         char *buf;
 220
 221         struct mm_struct *mm;
 222         struct work_struct work;
 223
 224         struct usb_ep *ep;
 225         struct usb_request *req;
 226         struct sg_table sgt;
 227         bool use_sg;
 228
 229         struct ffs_data *ffs;
 230 };
 231
 232 struct ffs_desc_helper {
 233         struct ffs_data *ffs;
 234         unsigned interfaces_count;
 235         unsigned eps_count;
 236 };
 237
 238 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 239 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 240
 241 static struct dentry *
 242 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 243                    const struct file_operations *fops);
 244
 245 /* Devices management *******************************************************/
 246
 247 DEFINE_MUTEX(ffs_lock);
 248 EXPORT_SYMBOL_GPL(ffs_lock);
 249
 250 static struct ffs_dev *_ffs_find_dev(const char *name);
 251 static struct ffs_dev *_ffs_alloc_dev(void);
 252 static void _ffs_free_dev(struct ffs_dev *dev);
 253 static void *ffs_acquire_dev(const char *dev_name);
 254 static void ffs_release_dev(struct ffs_data *ffs_data);
 255 static int ffs_ready(struct ffs_data *ffs);
 256 static void ffs_closed(struct ffs_data *ffs);
 257
 258 /* Misc helper functions ****************************************************/
 259
 260 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 261         __attribute__((warn_unused_result, nonnull));
 262 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 263         __attribute__((warn_unused_result, nonnull));
 264
 265
 266 /* Control file aka ep0 *****************************************************/
 267
 268 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 269 {
 270         struct ffs_data *ffs = req->context;
 271
 272         complete(&ffs->ep0req_completion);
 273 }
 274
 275 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 276         __releases(&ffs->ev.waitq.lock)
 277 {
 278         struct usb_request *req = ffs->ep0req;
 279         int ret;
 280
 281         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 282
 283         spin_unlock_irq(&ffs->ev.waitq.lock);
 284
 285         req->buf      = data;
 286         req->length   = len;
 287
 288         /*
 289          * UDC layer requires to provide a buffer even for ZLP, but should
 290          * not use it at all. Let's provide some poisoned pointer to catch
 291          * possible bug in the driver.
 292          */
 293         if (req->buf == NULL)
 294                 req->buf = (void *)0xDEADBABE;
 295
 296         reinit_completion(&ffs->ep0req_completion);
 297
 298         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 299         if (unlikely(ret < 0))
 300                 return ret;
 301
 302         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 303         if (unlikely(ret)) {
 304                 usb_ep_dequeue(ffs->gadget->ep0, req);
 305                 return -EINTR;
 306         }
 307
 308         ffs->setup_state = FFS_NO_SETUP;
 309         return req->status ? req->status : req->actual;
 310 }
 311
 312 static int __ffs_ep0_stall(struct ffs_data *ffs)
 313 {
 314         if (ffs->ev.can_stall) {
 315                 pr_vdebug("ep0 stall\n");
 316                 usb_ep_set_halt(ffs->gadget->ep0);
 317                 ffs->setup_state = FFS_NO_SETUP;
 318                 return -EL2HLT;
 319         } else {
 320                 pr_debug("bogus ep0 stall!\n");
 321                 return -ESRCH;
 322         }
 323 }
 324
 325 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 326                              size_t len, loff_t *ptr)
 327 {
 328         struct ffs_data *ffs = file->private_data;
 329         ssize_t ret;
 330         char *data;
 331
 332         ENTER();
 333
 334         /* Fast check if setup was canceled */
 335         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 336                 return -EIDRM;
 337
 338         /* Acquire mutex */
 339         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 340         if (unlikely(ret < 0))
 341                 return ret;
 342
 343         /* Check state */
 344         switch (ffs->state) {
 345         case FFS_READ_DESCRIPTORS:
 346         case FFS_READ_STRINGS:
 347                 /* Copy data */
 348                 if (unlikely(len < 16)) {
 349                         ret = -EINVAL;
 350                         break;
 351                 }
 352
 353                 data = ffs_prepare_buffer(buf, len);
 354                 if (IS_ERR(data)) {
 355                         ret = PTR_ERR(data);
 356                         break;
 357                 }
 358
 359                 /* Handle data */
 360                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 361                         pr_info("read descriptors\n");
 362                         ret = __ffs_data_got_descs(ffs, data, len);
 363                         if (unlikely(ret < 0))
 364                                 break;
 365
 366                         ffs->state = FFS_READ_STRINGS;
 367                         ret = len;
 368                 } else {
 369                         pr_info("read strings\n");
 370                         ret = __ffs_data_got_strings(ffs, data, len);
 371                         if (unlikely(ret < 0))
 372                                 break;
 373
 374                         ret = ffs_epfiles_create(ffs);
 375                         if (unlikely(ret)) {
 376                                 ffs->state = FFS_CLOSING;
 377                                 break;
 378                         }
 379
 380                         ffs->state = FFS_ACTIVE;
 381                         mutex_unlock(&ffs->mutex);
 382
 383                         ret = ffs_ready(ffs);
 384                         if (unlikely(ret < 0)) {
 385                                 ffs->state = FFS_CLOSING;
 386                                 return ret;
 387                         }
 388
 389                         return len;
 390                 }
 391                 break;
 392
 393         case FFS_ACTIVE:
 394                 data = NULL;
 395                 /*
 396                  * We're called from user space, we can use _irq
 397                  * rather then _irqsave
 398                  */
 399                 spin_lock_irq(&ffs->ev.waitq.lock);
 400                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 401                 case FFS_SETUP_CANCELLED:
 402                         ret = -EIDRM;
 403                         goto done_spin;
 404
 405                 case FFS_NO_SETUP:
 406                         ret = -ESRCH;
 407                         goto done_spin;
 408
 409                 case FFS_SETUP_PENDING:
 410                         break;
 411                 }
 412
 413                 /* FFS_SETUP_PENDING */
 414                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 415                         spin_unlock_irq(&ffs->ev.waitq.lock);
 416                         ret = __ffs_ep0_stall(ffs);
 417                         break;
 418                 }
 419
 420                 /* FFS_SETUP_PENDING and not stall */
 421                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 422
 423                 spin_unlock_irq(&ffs->ev.waitq.lock);
 424
 425                 data = ffs_prepare_buffer(buf, len);
 426                 if (IS_ERR(data)) {
 427                         ret = PTR_ERR(data);
 428                         break;
 429                 }
 430
 431                 spin_lock_irq(&ffs->ev.waitq.lock);
 432
 433                 /*
 434                  * We are guaranteed to be still in FFS_ACTIVE state
 435                  * but the state of setup could have changed from
 436                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 437                  * to check for that.  If that happened we copied data
 438                  * from user space in vain but it's unlikely.
 439                  *
 440                  * For sure we are not in FFS_NO_SETUP since this is
 441                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 442                  * transition can be performed and it's protected by
 443                  * mutex.
 444                  */
 445                 if (ffs_setup_state_clear_cancelled(ffs) ==
 446                     FFS_SETUP_CANCELLED) {
 447                         ret = -EIDRM;
 448 done_spin:
 449                         spin_unlock_irq(&ffs->ev.waitq.lock);
 450                 } else {
 451                         /* unlocks spinlock */
 452                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 453                 }
 454                 kfree(data);
 455                 break;
 456
 457         default:
 458                 ret = -EBADFD;
 459                 break;
 460         }
 461
 462         mutex_unlock(&ffs->mutex);
 463         return ret;
 464 }
 465
 466 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 467 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 468                                      size_t n)
 469         __releases(&ffs->ev.waitq.lock)
 470 {
 471         /*
 472          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 473          * size of ffs->ev.types array (which is four) so that's how much space
 474          * we reserve.
 475          */
 476         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 477         const size_t size = n * sizeof *events;
 478         unsigned i = 0;
 479
 480         memset(events, 0, size);
 481
 482         do {
 483                 events[i].type = ffs->ev.types[i];
 484                 if (events[i].type == FUNCTIONFS_SETUP) {
 485                         events[i].u.setup = ffs->ev.setup;
 486                         ffs->setup_state = FFS_SETUP_PENDING;
 487                 }
 488         } while (++i < n);
 489
 490         ffs->ev.count -= n;
 491         if (ffs->ev.count)
 492                 memmove(ffs->ev.types, ffs->ev.types + n,
 493                         ffs->ev.count * sizeof *ffs->ev.types);
 494
 495         spin_unlock_irq(&ffs->ev.waitq.lock);
 496         mutex_unlock(&ffs->mutex);
 497
 498         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 499 }
 500
 501 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 502                             size_t len, loff_t *ptr)
 503 {
 504         struct ffs_data *ffs = file->private_data;
 505         char *data = NULL;
 506         size_t n;
 507         int ret;
 508
 509         ENTER();
 510
 511         /* Fast check if setup was canceled */
 512         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 513                 return -EIDRM;
 514
 515         /* Acquire mutex */
 516         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 517         if (unlikely(ret < 0))
 518                 return ret;
 519
 520         /* Check state */
 521         if (ffs->state != FFS_ACTIVE) {
 522                 ret = -EBADFD;
 523                 goto done_mutex;
 524         }
 525
 526         /*
 527          * We're called from user space, we can use _irq rather then
 528          * _irqsave
 529          */
 530         spin_lock_irq(&ffs->ev.waitq.lock);
 531
 532         switch (ffs_setup_state_clear_cancelled(ffs)) {
 533         case FFS_SETUP_CANCELLED:
 534                 ret = -EIDRM;
 535                 break;
 536
 537         case FFS_NO_SETUP:
 538                 n = len / sizeof(struct usb_functionfs_event);
 539                 if (unlikely(!n)) {
 540                         ret = -EINVAL;
 541                         break;
 542                 }
 543
 544                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 545                         ret = -EAGAIN;
 546                         break;
 547                 }
 548
 549                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 550                                                         ffs->ev.count)) {
 551                         ret = -EINTR;
 552                         break;
 553                 }
 554
 555                 /* unlocks spinlock */
 556                 return __ffs_ep0_read_events(ffs, buf,
 557                                              min(n, (size_t)ffs->ev.count));
 558
 559         case FFS_SETUP_PENDING:
 560                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 561                         spin_unlock_irq(&ffs->ev.waitq.lock);
 562                         ret = __ffs_ep0_stall(ffs);
 563                         goto done_mutex;
 564                 }
 565
 566                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 567
 568                 spin_unlock_irq(&ffs->ev.waitq.lock);
 569
 570                 if (likely(len)) {
 571                         data = kmalloc(len, GFP_KERNEL);
 572                         if (unlikely(!data)) {
 573                                 ret = -ENOMEM;
 574                                 goto done_mutex;
 575                         }
 576                 }
 577
 578                 spin_lock_irq(&ffs->ev.waitq.lock);
 579
 580                 /* See ffs_ep0_write() */
 581                 if (ffs_setup_state_clear_cancelled(ffs) ==
 582                     FFS_SETUP_CANCELLED) {
 583                         ret = -EIDRM;
 584                         break;
 585                 }
 586
 587                 /* unlocks spinlock */
 588                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 589                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 590                         ret = -EFAULT;
 591                 goto done_mutex;
 592
 593         default:
 594                 ret = -EBADFD;
 595                 break;
 596         }
 597
 598         spin_unlock_irq(&ffs->ev.waitq.lock);
 599 done_mutex:
 600         mutex_unlock(&ffs->mutex);
 601         kfree(data);
 602         return ret;
 603 }
 604
 605 static int ffs_ep0_open(struct inode *inode, struct file *file)
 606 {
 607         struct ffs_data *ffs = inode->i_private;
 608
 609         ENTER();
 610
 611         if (unlikely(ffs->state == FFS_CLOSING))
 612                 return -EBUSY;
 613
 614         file->private_data = ffs;
 615         ffs_data_opened(ffs);
 616
 617         return 0;
 618 }
 619
 620 static int ffs_ep0_release(struct inode *inode, struct file *file)
 621 {
 622         struct ffs_data *ffs = file->private_data;
 623
 624         ENTER();
 625
 626         ffs_data_closed(ffs);
 627
 628         return 0;
 629 }
 630
 631 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 632 {
 633         struct ffs_data *ffs = file->private_data;
 634         struct usb_gadget *gadget = ffs->gadget;
 635         long ret;
 636
 637         ENTER();
 638
 639         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 640                 struct ffs_function *func = ffs->func;
 641                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 642         } else if (gadget && gadget->ops->ioctl) {
 643                 ret = gadget->ops->ioctl(gadget, code, value);
 644         } else {
 645                 ret = -ENOTTY;
 646         }
 647
 648         return ret;
 649 }
 650
 651 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 652 {
 653         struct ffs_data *ffs = file->private_data;
 654         __poll_t mask = EPOLLWRNORM;
 655         int ret;
 656
 657         poll_wait(file, &ffs->ev.waitq, wait);
 658
 659         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 660         if (unlikely(ret < 0))
 661                 return mask;
 662
 663         switch (ffs->state) {
 664         case FFS_READ_DESCRIPTORS:
 665         case FFS_READ_STRINGS:
 666                 mask |= EPOLLOUT;
 667                 break;
 668
 669         case FFS_ACTIVE:
 670                 switch (ffs->setup_state) {
 671                 case FFS_NO_SETUP:
 672                         if (ffs->ev.count)
 673                                 mask |= EPOLLIN;
 674                         break;
 675
 676                 case FFS_SETUP_PENDING:
 677                 case FFS_SETUP_CANCELLED:
 678                         mask |= (EPOLLIN | EPOLLOUT);
 679                         break;
 680                 }
 681         case FFS_CLOSING:
 682                 break;
 683         case FFS_DEACTIVATED:
 684                 break;
 685         }
 686
 687         mutex_unlock(&ffs->mutex);
 688
 689         return mask;
 690 }
 691
 692 static const struct file_operations ffs_ep0_operations = {
 693         .llseek =       no_llseek,
 694
 695         .open =         ffs_ep0_open,
 696         .write =        ffs_ep0_write,
 697         .read =         ffs_ep0_read,
 698         .release =      ffs_ep0_release,
 699         .unlocked_ioctl =       ffs_ep0_ioctl,
 700         .poll =         ffs_ep0_poll,
 701 };
 702
 703
 704 /* "Normal" endpoints operations ********************************************/
 705
 706 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 707 {
 708         ENTER();
 709         if (likely(req->context)) {
 710                 struct ffs_ep *ep = _ep->driver_data;
 711                 ep->status = req->status ? req->status : req->actual;
 712                 complete(req->context);
 713         }
 714 }
 715
 716 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 717 {
 718         ssize_t ret = copy_to_iter(data, data_len, iter);
 719         if (likely(ret == data_len))
 720                 return ret;
 721
 722         if (unlikely(iov_iter_count(iter)))
 723                 return -EFAULT;
 724
 725         /*
 726          * Dear user space developer!
 727          *
 728          * TL;DR: To stop getting below error message in your kernel log, change
 729          * user space code using functionfs to align read buffers to a max
 730          * packet size.
 731          *
 732          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 733          * packet size.  When unaligned buffer is passed to functionfs, it
 734          * internally uses a larger, aligned buffer so that such UDCs are happy.
 735          *
 736          * Unfortunately, this means that host may send more data than was
 737          * requested in read(2) system call.  f_fs doesn’t know what to do with
 738          * that excess data so it simply drops it.
 739          *
 740          * Was the buffer aligned in the first place, no such problem would
 741          * happen.
 742          *
 743          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 744          * by splitting a request into multiple parts.  This splitting may still
 745          * be a problem though so it’s likely best to align the buffer
 746          * regardless of it being AIO or not..
 747          *
 748          * This only affects OUT endpoints, i.e. reading data with a read(2),
 749          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 750          * affected.
 751          */
 752         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 753                "Align read buffer size to max packet size to avoid the problem.\n",
 754                data_len, ret);
 755
 756         return ret;
 757 }
 758
 759 /*
 760  * allocate a virtually contiguous buffer and create a scatterlist describing it
 761  * @sg_table    - pointer to a place to be filled with sg_table contents
 762  * @size        - required buffer size
 763  */
 764 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 765 {
 766         struct page **pages;
 767         void *vaddr, *ptr;
 768         unsigned int n_pages;
 769         int i;
 770
 771         vaddr = vmalloc(sz);
 772         if (!vaddr)
 773                 return NULL;
 774
 775         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 776         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 777         if (!pages) {
 778                 vfree(vaddr);
 779
 780                 return NULL;
 781         }
 782         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 783                 pages[i] = vmalloc_to_page(ptr);
 784
 785         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 786                 kvfree(pages);
 787                 vfree(vaddr);
 788
 789                 return NULL;
 790         }
 791         kvfree(pages);
 792
 793         return vaddr;
 794 }
 795
 796 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 797         size_t data_len)
 798 {
 799         if (io_data->use_sg)
 800                 return ffs_build_sg_list(&io_data->sgt, data_len);
 801
 802         return kmalloc(data_len, GFP_KERNEL);
 803 }
 804
 805 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 806 {
 807         if (!io_data->buf)
 808                 return;
 809
 810         if (io_data->use_sg) {
 811                 sg_free_table(&io_data->sgt);
 812                 vfree(io_data->buf);
 813         } else {
 814                 kfree(io_data->buf);
 815         }
 816 }
 817
 818 static void ffs_user_copy_worker(struct work_struct *work)
 819 {
 820         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 821                                                    work);
 822         int ret = io_data->req->status ? io_data->req->status :
 823                                          io_data->req->actual;
 824         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 825
 826         if (io_data->read && ret > 0) {
 827                 kthread_use_mm(io_data->mm);
 828                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 829                 kthread_unuse_mm(io_data->mm);
 830         }
 831
 832         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 833
 834         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 835                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 836
 837         usb_ep_free_request(io_data->ep, io_data->req);
 838
 839         if (io_data->read)
 840                 kfree(io_data->to_free);
 841         ffs_free_buffer(io_data);
 842         kfree(io_data);
 843 }
 844
 845 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 846                                          struct usb_request *req)
 847 {
 848         struct ffs_io_data *io_data = req->context;
 849         struct ffs_data *ffs = io_data->ffs;
 850
 851         ENTER();
 852
 853         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 854         queue_work(ffs->io_completion_wq, &io_data->work);
 855 }
 856
 857 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 858 {
 859         /*
 860          * See comment in struct ffs_epfile for full read_buffer pointer
 861          * synchronisation story.
 862          */
 863         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 864         if (buf && buf != READ_BUFFER_DROP)
 865                 kfree(buf);
 866 }
 867
 868 /* Assumes epfile->mutex is held. */
 869 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 870                                           struct iov_iter *iter)
 871 {
 872         /*
 873          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 874          * the buffer while we are using it.  See comment in struct ffs_epfile
 875          * for full read_buffer pointer synchronisation story.
 876          */
 877         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 878         ssize_t ret;
 879         if (!buf || buf == READ_BUFFER_DROP)
 880                 return 0;
 881
 882         ret = copy_to_iter(buf->data, buf->length, iter);
 883         if (buf->length == ret) {
 884                 kfree(buf);
 885                 return ret;
 886         }
 887
 888         if (unlikely(iov_iter_count(iter))) {
 889                 ret = -EFAULT;
 890         } else {
 891                 buf->length -= ret;
 892                 buf->data += ret;
 893         }
 894
 895         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 896                 kfree(buf);
 897
 898         return ret;
 899 }
 900
 901 /* Assumes epfile->mutex is held. */
 902 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 903                                       void *data, int data_len,
 904                                       struct iov_iter *iter)
 905 {
 906         struct ffs_buffer *buf;
 907
 908         ssize_t ret = copy_to_iter(data, data_len, iter);
 909         if (likely(data_len == ret))
 910                 return ret;
 911
 912         if (unlikely(iov_iter_count(iter)))
 913                 return -EFAULT;
 914
 915         /* See ffs_copy_to_iter for more context. */
 916         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 917                 data_len, ret);
 918
 919         data_len -= ret;
 920         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 921         if (!buf)
 922                 return -ENOMEM;
 923         buf->length = data_len;
 924         buf->data = buf->storage;
 925         memcpy(buf->storage, data + ret, data_len);
 926
 927         /*
 928          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 929          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 930          * in struct ffs_epfile for full read_buffer pointer synchronisation
 931          * story.
 932          */
 933         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 934                 kfree(buf);
 935
 936         return ret;
 937 }
 938
 939 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 940 {
 941         struct ffs_epfile *epfile = file->private_data;
 942         struct usb_request *req;
 943         struct ffs_ep *ep;
 944         char *data = NULL;
 945         ssize_t ret, data_len = -EINVAL;
 946         int halt;
 947
 948         /* Are we still active? */
 949         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 950                 return -ENODEV;
 951
 952         /* Wait for endpoint to be enabled */
 953         ep = epfile->ep;
 954         if (!ep) {
 955                 if (file->f_flags & O_NONBLOCK)
 956                         return -EAGAIN;
 957
 958                 ret = wait_event_interruptible(
 959                                 epfile->ffs->wait, (ep = epfile->ep));
 960                 if (ret)
 961                         return -EINTR;
 962         }
 963
 964         /* Do we halt? */
 965         halt = (!io_data->read == !epfile->in);
 966         if (halt && epfile->isoc)
 967                 return -EINVAL;
 968
 969         /* We will be using request and read_buffer */
 970         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 971         if (unlikely(ret))
 972                 goto error;
 973
 974         /* Allocate & copy */
 975         if (!halt) {
 976                 struct usb_gadget *gadget;
 977
 978                 /*
 979                  * Do we have buffered data from previous partial read?  Check
 980                  * that for synchronous case only because we do not have
 981                  * facility to ‘wake up’ a pending asynchronous read and push
 982                  * buffered data to it which we would need to make things behave
 983                  * consistently.
 984                  */
 985                 if (!io_data->aio && io_data->read) {
 986                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 987                         if (ret)
 988                                 goto error_mutex;
 989                 }
 990
 991                 /*
 992                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 993                  * before the waiting completes, so do not assign to 'gadget'
 994                  * earlier
 995                  */
 996                 gadget = epfile->ffs->gadget;
 997
 998                 spin_lock_irq(&epfile->ffs->eps_lock);
 999                 /* In the meantime, endpoint got disabled or changed. */
1000                 if (epfile->ep != ep) {
1001                         ret = -ESHUTDOWN;
1002                         goto error_lock;
1003                 }
1004                 data_len = iov_iter_count(&io_data->data);
1005                 /*
1006                  * Controller may require buffer size to be aligned to
1007                  * maxpacketsize of an out endpoint.
1008                  */
1009                 if (io_data->read)
1010                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1011
1012                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1013                 spin_unlock_irq(&epfile->ffs->eps_lock);
1014
1015 retry_malloc:
1016                 data = kmalloc(data_len, GFP_KERNEL | __GFP_NOWARN);
1017                 if (unlikely(!data)) {
1018                         /*
1019                          * f_fs daemons usually use large size buffer for
1020                          * performance. However, this can cause failure of
1021                          * kmalloc() due to buddy fragmentation, even if there
1022                          * is available memory and thus it can be compacted by
1023                          * by kswapd. Therefore, instead of just returning error
1024                          * to daemon in the case of failure of kmalloc(), give
1025                          * the second chance to allocate buffer with a half size
1026                          * until it really fails due to memory shortage.
1027                          */
1028                         if (unlikely(data_len <= PAGE_SIZE)) {
1029                                 ret = -ENOMEM;
1030                                 goto error_mutex;
1031                         }
1032
1033                         data_len = data_len >> 1;
1034
1035                         if (io_data->read) {
1036                                 spin_lock_irq(&epfile->ffs->eps_lock);
1037                                 data_len = usb_ep_align_maybe(gadget,
1038                                                 ep->ep, data_len);
1039                                 spin_unlock_irq(&epfile->ffs->eps_lock);
1040                         }
1041
1042                         goto retry_malloc;
1043                 }
1044                 if (!io_data->read &&
1045                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1046                         ret = -EFAULT;
1047                         goto error_mutex;
1048                 }
1049         }
1050
1051         spin_lock_irq(&epfile->ffs->eps_lock);
1052
1053         if (epfile->ep != ep) {
1054                 /* In the meantime, endpoint got disabled or changed. */
1055                 ret = -ESHUTDOWN;
1056         } else if (halt) {
1057                 ret = usb_ep_set_halt(ep->ep);
1058                 if (!ret)
1059                         ret = -EBADMSG;
1060         } else if (unlikely(data_len == -EINVAL)) {
1061                 /*
1062                  * Sanity Check: even though data_len can't be used
1063                  * uninitialized at the time I write this comment, some
1064                  * compilers complain about this situation.
1065                  * In order to keep the code clean from warnings, data_len is
1066                  * being initialized to -EINVAL during its declaration, which
1067                  * means we can't rely on compiler anymore to warn no future
1068                  * changes won't result in data_len being used uninitialized.
1069                  * For such reason, we're adding this redundant sanity check
1070                  * here.
1071                  */
1072                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1073                 ret = -EINVAL;
1074         } else if (!io_data->aio) {
1075                 DECLARE_COMPLETION_ONSTACK(done);
1076                 bool interrupted = false;
1077
1078                 req = ep->req;
1079                 if (io_data->use_sg) {
1080                         req->buf = NULL;
1081                         req->sg = io_data->sgt.sgl;
1082                         req->num_sgs = io_data->sgt.nents;
1083                 } else {
1084                         req->buf = data;
1085                         req->num_sgs = 0;
1086                 }
1087                 req->length = data_len;
1088
1089                 io_data->buf = data;
1090
1091                 req->context  = &done;
1092                 req->complete = ffs_epfile_io_complete;
1093
1094                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1095                 if (unlikely(ret < 0))
1096                         goto error_lock;
1097
1098                 spin_unlock_irq(&epfile->ffs->eps_lock);
1099
1100                 if (unlikely(wait_for_completion_interruptible(&done)) &&
1101                     epfile->ep) {
1102                         /*
1103                          * To avoid race condition with ffs_epfile_io_complete,
1104                          * dequeue the request first then check
1105                          * status. usb_ep_dequeue API should guarantee no race
1106                          * condition with req->complete callback.
1107                          */
1108                         usb_ep_dequeue(ep->ep, req);
1109                         wait_for_completion(&done);
1110                         interrupted = ep->status < 0;
1111                 }
1112
1113                 if (epfile->ep != ep) {
1114                         /* In the meantime, endpoint got disabled or changed. */
1115                         ret = -ESHUTDOWN;
1116                         goto error_mutex;
1117                 }
1118
1119                 if (interrupted)
1120                         ret = -EINTR;
1121                 else if (io_data->read && ep->status > 0)
1122                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1123                                                      &io_data->data);
1124                 else
1125                         ret = ep->status;
1126                 goto error_mutex;
1127         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1128                 ret = -ENOMEM;
1129         } else {
1130                 if (io_data->use_sg) {
1131                         req->buf = NULL;
1132                         req->sg = io_data->sgt.sgl;
1133                         req->num_sgs = io_data->sgt.nents;
1134                 } else {
1135                         req->buf = data;
1136                         req->num_sgs = 0;
1137                 }
1138                 req->length = data_len;
1139
1140                 io_data->buf = data;
1141                 io_data->ep = ep->ep;
1142                 io_data->req = req;
1143                 io_data->ffs = epfile->ffs;
1144
1145                 req->context  = io_data;
1146                 req->complete = ffs_epfile_async_io_complete;
1147
1148                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1149                 if (unlikely(ret)) {
1150                         io_data->req = NULL;
1151                         usb_ep_free_request(ep->ep, req);
1152                         goto error_lock;
1153                 }
1154
1155                 ret = -EIOCBQUEUED;
1156                 /*
1157                  * Do not kfree the buffer in this function.  It will be freed
1158                  * by ffs_user_copy_worker.
1159                  */
1160                 data = NULL;
1161         }
1162
1163 error_lock:
1164         spin_unlock_irq(&epfile->ffs->eps_lock);
1165 error_mutex:
1166         mutex_unlock(&epfile->mutex);
1167 error:
1168         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1169                 ffs_free_buffer(io_data);
1170         return ret;
1171 }
1172
1173 static int
1174 ffs_epfile_open(struct inode *inode, struct file *file)
1175 {
1176         struct ffs_epfile *epfile = inode->i_private;
1177
1178         ENTER();
1179
1180         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1181                 return -ENODEV;
1182
1183         file->private_data = epfile;
1184         ffs_data_opened(epfile->ffs);
1185
1186         return 0;
1187 }
1188
1189 static int ffs_aio_cancel(struct kiocb *kiocb)
1190 {
1191         struct ffs_io_data *io_data = kiocb->private;
1192         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1193         unsigned long flags;
1194         int value;
1195
1196         ENTER();
1197
1198         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1199
1200         if (likely(io_data && io_data->ep && io_data->req))
1201                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1202         else
1203                 value = -EINVAL;
1204
1205         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1206
1207         return value;
1208 }
1209
1210 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1211 {
1212         struct ffs_io_data io_data, *p = &io_data;
1213         ssize_t res;
1214
1215         ENTER();
1216
1217         if (!is_sync_kiocb(kiocb)) {
1218                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1219                 if (unlikely(!p))
1220                         return -ENOMEM;
1221                 p->aio = true;
1222         } else {
1223                 memset(p, 0, sizeof(*p));
1224                 p->aio = false;
1225         }
1226
1227         p->read = false;
1228         p->kiocb = kiocb;
1229         p->data = *from;
1230         p->mm = current->mm;
1231
1232         kiocb->private = p;
1233
1234         if (p->aio)
1235                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1236
1237         res = ffs_epfile_io(kiocb->ki_filp, p);
1238         if (res == -EIOCBQUEUED)
1239                 return res;
1240         if (p->aio)
1241                 kfree(p);
1242         else
1243                 *from = p->data;
1244         return res;
1245 }
1246
1247 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1248 {
1249         struct ffs_io_data io_data, *p = &io_data;
1250         ssize_t res;
1251
1252         ENTER();
1253
1254         if (!is_sync_kiocb(kiocb)) {
1255                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1256                 if (unlikely(!p))
1257                         return -ENOMEM;
1258                 p->aio = true;
1259         } else {
1260                 memset(p, 0, sizeof(*p));
1261                 p->aio = false;
1262         }
1263
1264         p->read = true;
1265         p->kiocb = kiocb;
1266         if (p->aio) {
1267                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1268                 if (!p->to_free) {
1269                         kfree(p);
1270                         return -ENOMEM;
1271                 }
1272         } else {
1273                 p->data = *to;
1274                 p->to_free = NULL;
1275         }
1276         p->mm = current->mm;
1277
1278         kiocb->private = p;
1279
1280         if (p->aio)
1281                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1282
1283         res = ffs_epfile_io(kiocb->ki_filp, p);
1284         if (res == -EIOCBQUEUED)
1285                 return res;
1286
1287         if (p->aio) {
1288                 kfree(p->to_free);
1289                 kfree(p);
1290         } else {
1291                 *to = p->data;
1292         }
1293         return res;
1294 }
1295
1296 static int
1297 ffs_epfile_release(struct inode *inode, struct file *file)
1298 {
1299         struct ffs_epfile *epfile = inode->i_private;
1300
1301         ENTER();
1302
1303         __ffs_epfile_read_buffer_free(epfile);
1304         ffs_data_closed(epfile->ffs);
1305
1306         return 0;
1307 }
1308
1309 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1310                              unsigned long value)
1311 {
1312         struct ffs_epfile *epfile = file->private_data;
1313         struct ffs_ep *ep;
1314         int ret;
1315
1316         ENTER();
1317
1318         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1319                 return -ENODEV;
1320
1321         /* Wait for endpoint to be enabled */
1322         ep = epfile->ep;
1323         if (!ep) {
1324                 if (file->f_flags & O_NONBLOCK)
1325                         return -EAGAIN;
1326
1327                 ret = wait_event_interruptible(
1328                                 epfile->ffs->wait, (ep = epfile->ep));
1329                 if (ret)
1330                         return -EINTR;
1331         }
1332
1333         spin_lock_irq(&epfile->ffs->eps_lock);
1334
1335         /* In the meantime, endpoint got disabled or changed. */
1336         if (epfile->ep != ep) {
1337                 spin_unlock_irq(&epfile->ffs->eps_lock);
1338                 return -ESHUTDOWN;
1339         }
1340
1341         switch (code) {
1342         case FUNCTIONFS_FIFO_STATUS:
1343                 ret = usb_ep_fifo_status(epfile->ep->ep);
1344                 break;
1345         case FUNCTIONFS_FIFO_FLUSH:
1346                 usb_ep_fifo_flush(epfile->ep->ep);
1347                 ret = 0;
1348                 break;
1349         case FUNCTIONFS_CLEAR_HALT:
1350                 ret = usb_ep_clear_halt(epfile->ep->ep);
1351                 break;
1352         case FUNCTIONFS_ENDPOINT_REVMAP:
1353                 ret = epfile->ep->num;
1354                 break;
1355         case FUNCTIONFS_ENDPOINT_DESC:
1356         {
1357                 int desc_idx;
1358                 struct usb_endpoint_descriptor desc1, *desc;
1359
1360                 switch (epfile->ffs->gadget->speed) {
1361                 case USB_SPEED_SUPER:
1362                 case USB_SPEED_SUPER_PLUS:
1363                         desc_idx = 2;
1364                         break;
1365                 case USB_SPEED_HIGH:
1366                         desc_idx = 1;
1367                         break;
1368                 default:
1369                         desc_idx = 0;
1370                 }
1371
1372                 desc = epfile->ep->descs[desc_idx];
1373                 memcpy(&desc1, desc, desc->bLength);
1374
1375                 spin_unlock_irq(&epfile->ffs->eps_lock);
1376                 ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
1377                 if (ret)
1378                         ret = -EFAULT;
1379                 return ret;
1380         }
1381         default:
1382                 ret = -ENOTTY;
1383         }
1384         spin_unlock_irq(&epfile->ffs->eps_lock);
1385
1386         return ret;
1387 }
1388
1389 static const struct file_operations ffs_epfile_operations = {
1390         .llseek =       no_llseek,
1391
1392         .open =         ffs_epfile_open,
1393         .write_iter =   ffs_epfile_write_iter,
1394         .read_iter =    ffs_epfile_read_iter,
1395         .release =      ffs_epfile_release,
1396         .unlocked_ioctl =       ffs_epfile_ioctl,
1397         .compat_ioctl = compat_ptr_ioctl,
1398 };
1399
1400
1401 /* File system and super block operations ***********************************/
1402
1403 /*
1404  * Mounting the file system creates a controller file, used first for
1405  * function configuration then later for event monitoring.
1406  */
1407
1408 static struct inode *__must_check
1409 ffs_sb_make_inode(struct super_block *sb, void *data,
1410                   const struct file_operations *fops,
1411                   const struct inode_operations *iops,
1412                   struct ffs_file_perms *perms)
1413 {
1414         struct inode *inode;
1415
1416         ENTER();
1417
1418         inode = new_inode(sb);
1419
1420         if (likely(inode)) {
1421                 struct timespec64 ts = current_time(inode);
1422
1423                 inode->i_ino     = get_next_ino();
1424                 inode->i_mode    = perms->mode;
1425                 inode->i_uid     = perms->uid;
1426                 inode->i_gid     = perms->gid;
1427                 inode->i_atime   = ts;
1428                 inode->i_mtime   = ts;
1429                 inode->i_ctime   = ts;
1430                 inode->i_private = data;
1431                 if (fops)
1432                         inode->i_fop = fops;
1433                 if (iops)
1434                         inode->i_op  = iops;
1435         }
1436
1437         return inode;
1438 }
1439
1440 /* Create "regular" file */
1441 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1442                                         const char *name, void *data,
1443                                         const struct file_operations *fops)
1444 {
1445         struct ffs_data *ffs = sb->s_fs_info;
1446         struct dentry   *dentry;
1447         struct inode    *inode;
1448
1449         ENTER();
1450
1451         dentry = d_alloc_name(sb->s_root, name);
1452         if (unlikely(!dentry))
1453                 return NULL;
1454
1455         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1456         if (unlikely(!inode)) {
1457                 dput(dentry);
1458                 return NULL;
1459         }
1460
1461         d_add(dentry, inode);
1462         return dentry;
1463 }
1464
1465 /* Super block */
1466 static const struct super_operations ffs_sb_operations = {
1467         .statfs =       simple_statfs,
1468         .drop_inode =   generic_delete_inode,
1469 };
1470
1471 struct ffs_sb_fill_data {
1472         struct ffs_file_perms perms;
1473         umode_t root_mode;
1474         const char *dev_name;
1475         bool no_disconnect;
1476         struct ffs_data *ffs_data;
1477 };
1478
1479 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1480 {
1481         struct ffs_sb_fill_data *data = fc->fs_private;
1482         struct inode    *inode;
1483         struct ffs_data *ffs = data->ffs_data;
1484
1485         ENTER();
1486
1487         ffs->sb              = sb;
1488         data->ffs_data       = NULL;
1489         sb->s_fs_info        = ffs;
1490         sb->s_blocksize      = PAGE_SIZE;
1491         sb->s_blocksize_bits = PAGE_SHIFT;
1492         sb->s_magic          = FUNCTIONFS_MAGIC;
1493         sb->s_op             = &ffs_sb_operations;
1494         sb->s_time_gran      = 1;
1495
1496         /* Root inode */
1497         data->perms.mode = data->root_mode;
1498         inode = ffs_sb_make_inode(sb, NULL,
1499                                   &simple_dir_operations,
1500                                   &simple_dir_inode_operations,
1501                                   &data->perms);
1502         sb->s_root = d_make_root(inode);
1503         if (unlikely(!sb->s_root))
1504                 return -ENOMEM;
1505
1506         /* EP0 file */
1507         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1508                                          &ffs_ep0_operations)))
1509                 return -ENOMEM;
1510
1511         return 0;
1512 }
1513
1514 enum {
1515         Opt_no_disconnect,
1516         Opt_rmode,
1517         Opt_fmode,
1518         Opt_mode,
1519         Opt_uid,
1520         Opt_gid,
1521 };
1522
1523 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1524         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1525         fsparam_u32     ("rmode",               Opt_rmode),
1526         fsparam_u32     ("fmode",               Opt_fmode),
1527         fsparam_u32     ("mode",                Opt_mode),
1528         fsparam_u32     ("uid",                 Opt_uid),
1529         fsparam_u32     ("gid",                 Opt_gid),
1530         {}
1531 };
1532
1533 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1534 {
1535         struct ffs_sb_fill_data *data = fc->fs_private;
1536         struct fs_parse_result result;
1537         int opt;
1538
1539         ENTER();
1540
1541         opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1542         if (opt < 0)
1543                 return opt;
1544
1545         switch (opt) {
1546         case Opt_no_disconnect:
1547                 data->no_disconnect = result.boolean;
1548                 break;
1549         case Opt_rmode:
1550                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1551                 break;
1552         case Opt_fmode:
1553                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1554                 break;
1555         case Opt_mode:
1556                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1557                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1558                 break;
1559
1560         case Opt_uid:
1561                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1562                 if (!uid_valid(data->perms.uid))
1563                         goto unmapped_value;
1564                 break;
1565         case Opt_gid:
1566                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1567                 if (!gid_valid(data->perms.gid))
1568                         goto unmapped_value;
1569                 break;
1570
1571         default:
1572                 return -ENOPARAM;
1573         }
1574
1575         return 0;
1576
1577 unmapped_value:
1578         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1579 }
1580
1581 /*
1582  * Set up the superblock for a mount.
1583  */
1584 static int ffs_fs_get_tree(struct fs_context *fc)
1585 {
1586         struct ffs_sb_fill_data *ctx = fc->fs_private;
1587         void *ffs_dev;
1588         struct ffs_data *ffs;
1589
1590         ENTER();
1591
1592         if (!fc->source)
1593                 return invalf(fc, "No source specified");
1594
1595         ffs = ffs_data_new(fc->source);
1596         if (unlikely(!ffs))
1597                 return -ENOMEM;
1598         ffs->file_perms = ctx->perms;
1599         ffs->no_disconnect = ctx->no_disconnect;
1600
1601         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1602         if (unlikely(!ffs->dev_name)) {
1603                 ffs_data_put(ffs);
1604                 return -ENOMEM;
1605         }
1606
1607         ffs_dev = ffs_acquire_dev(ffs->dev_name);
1608         if (IS_ERR(ffs_dev)) {
1609                 ffs_data_put(ffs);
1610                 return PTR_ERR(ffs_dev);
1611         }
1612
1613         ffs->private_data = ffs_dev;
1614         ctx->ffs_data = ffs;
1615         return get_tree_nodev(fc, ffs_sb_fill);
1616 }
1617
1618 static void ffs_fs_free_fc(struct fs_context *fc)
1619 {
1620         struct ffs_sb_fill_data *ctx = fc->fs_private;
1621
1622         if (ctx) {
1623                 if (ctx->ffs_data) {
1624                         ffs_release_dev(ctx->ffs_data);
1625                         ffs_data_put(ctx->ffs_data);
1626                 }
1627
1628                 kfree(ctx);
1629         }
1630 }
1631
1632 static const struct fs_context_operations ffs_fs_context_ops = {
1633         .free           = ffs_fs_free_fc,
1634         .parse_param    = ffs_fs_parse_param,
1635         .get_tree       = ffs_fs_get_tree,
1636 };
1637
1638 static int ffs_fs_init_fs_context(struct fs_context *fc)
1639 {
1640         struct ffs_sb_fill_data *ctx;
1641
1642         ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1643         if (!ctx)
1644                 return -ENOMEM;
1645
1646         ctx->perms.mode = S_IFREG | 0600;
1647         ctx->perms.uid = GLOBAL_ROOT_UID;
1648         ctx->perms.gid = GLOBAL_ROOT_GID;
1649         ctx->root_mode = S_IFDIR | 0500;
1650         ctx->no_disconnect = false;
1651
1652         fc->fs_private = ctx;
1653         fc->ops = &ffs_fs_context_ops;
1654         return 0;
1655 }
1656
1657 static void
1658 ffs_fs_kill_sb(struct super_block *sb)
1659 {
1660         ENTER();
1661
1662         kill_litter_super(sb);
1663         if (sb->s_fs_info) {
1664                 ffs_release_dev(sb->s_fs_info);
1665                 ffs_data_closed(sb->s_fs_info);
1666         }
1667 }
1668
1669 static struct file_system_type ffs_fs_type = {
1670         .owner          = THIS_MODULE,
1671         .name           = "functionfs",
1672         .init_fs_context = ffs_fs_init_fs_context,
1673         .parameters     = ffs_fs_fs_parameters,
1674         .kill_sb        = ffs_fs_kill_sb,
1675 };
1676 MODULE_ALIAS_FS("functionfs");
1677
1678
1679 /* Driver's main init/cleanup functions *************************************/
1680
1681 static int functionfs_init(void)
1682 {
1683         int ret;
1684
1685         ENTER();
1686
1687         ret = register_filesystem(&ffs_fs_type);
1688         if (likely(!ret))
1689                 pr_info("file system registered\n");
1690         else
1691                 pr_err("failed registering file system (%d)\n", ret);
1692
1693         return ret;
1694 }
1695
1696 static void functionfs_cleanup(void)
1697 {
1698         ENTER();
1699
1700         pr_info("unloading\n");
1701         unregister_filesystem(&ffs_fs_type);
1702 }
1703
1704
1705 /* ffs_data and ffs_function construction and destruction code **************/
1706
1707 static void ffs_data_clear(struct ffs_data *ffs);
1708 static void ffs_data_reset(struct ffs_data *ffs);
1709
1710 static void ffs_data_get(struct ffs_data *ffs)
1711 {
1712         ENTER();
1713
1714         refcount_inc(&ffs->ref);
1715 }
1716
1717 static void ffs_data_opened(struct ffs_data *ffs)
1718 {
1719         ENTER();
1720
1721         refcount_inc(&ffs->ref);
1722         if (atomic_add_return(1, &ffs->opened) == 1 &&
1723                         ffs->state == FFS_DEACTIVATED) {
1724                 ffs->state = FFS_CLOSING;
1725                 ffs_data_reset(ffs);
1726         }
1727 }
1728
1729 static void ffs_data_put(struct ffs_data *ffs)
1730 {
1731         ENTER();
1732
1733         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1734                 pr_info("%s(): freeing\n", __func__);
1735                 ffs_data_clear(ffs);
1736                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1737                        swait_active(&ffs->ep0req_completion.wait) ||
1738                        waitqueue_active(&ffs->wait));
1739                 destroy_workqueue(ffs->io_completion_wq);
1740                 kfree(ffs->dev_name);
1741                 kfree(ffs);
1742         }
1743 }
1744
1745 static void ffs_data_closed(struct ffs_data *ffs)
1746 {
1747         ENTER();
1748
1749         if (atomic_dec_and_test(&ffs->opened)) {
1750                 if (ffs->no_disconnect) {
1751                         ffs->state = FFS_DEACTIVATED;
1752                         if (ffs->epfiles) {
1753                                 ffs_epfiles_destroy(ffs->epfiles,
1754                                                    ffs->eps_count);
1755                                 ffs->epfiles = NULL;
1756                         }
1757                         if (ffs->setup_state == FFS_SETUP_PENDING)
1758                                 __ffs_ep0_stall(ffs);
1759                 } else {
1760                         ffs->state = FFS_CLOSING;
1761                         ffs_data_reset(ffs);
1762                 }
1763         }
1764         if (atomic_read(&ffs->opened) < 0) {
1765                 ffs->state = FFS_CLOSING;
1766                 ffs_data_reset(ffs);
1767         }
1768
1769         ffs_data_put(ffs);
1770 }
1771
1772 static struct ffs_data *ffs_data_new(const char *dev_name)
1773 {
1774         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1775         if (unlikely(!ffs))
1776                 return NULL;
1777
1778         ENTER();
1779
1780         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1781         if (!ffs->io_completion_wq) {
1782                 kfree(ffs);
1783                 return NULL;
1784         }
1785
1786         refcount_set(&ffs->ref, 1);
1787         atomic_set(&ffs->opened, 0);
1788         ffs->state = FFS_READ_DESCRIPTORS;
1789         mutex_init(&ffs->mutex);
1790         spin_lock_init(&ffs->eps_lock);
1791         init_waitqueue_head(&ffs->ev.waitq);
1792         init_waitqueue_head(&ffs->wait);
1793         init_completion(&ffs->ep0req_completion);
1794
1795         /* XXX REVISIT need to update it in some places, or do we? */
1796         ffs->ev.can_stall = 1;
1797
1798         return ffs;
1799 }
1800
1801 static void ffs_data_clear(struct ffs_data *ffs)
1802 {
1803         ENTER();
1804
1805         ffs_closed(ffs);
1806
1807         BUG_ON(ffs->gadget);
1808
1809         if (ffs->epfiles)
1810                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1811
1812         if (ffs->ffs_eventfd)
1813                 eventfd_ctx_put(ffs->ffs_eventfd);
1814
1815         kfree(ffs->raw_descs_data);
1816         kfree(ffs->raw_strings);
1817         kfree(ffs->stringtabs);
1818 }
1819
1820 static void ffs_data_reset(struct ffs_data *ffs)
1821 {
1822         ENTER();
1823
1824         ffs_data_clear(ffs);
1825
1826         ffs->epfiles = NULL;
1827         ffs->raw_descs_data = NULL;
1828         ffs->raw_descs = NULL;
1829         ffs->raw_strings = NULL;
1830         ffs->stringtabs = NULL;
1831
1832         ffs->raw_descs_length = 0;
1833         ffs->fs_descs_count = 0;
1834         ffs->hs_descs_count = 0;
1835         ffs->ss_descs_count = 0;
1836
1837         ffs->strings_count = 0;
1838         ffs->interfaces_count = 0;
1839         ffs->eps_count = 0;
1840
1841         ffs->ev.count = 0;
1842
1843         ffs->state = FFS_READ_DESCRIPTORS;
1844         ffs->setup_state = FFS_NO_SETUP;
1845         ffs->flags = 0;
1846
1847         ffs->ms_os_descs_ext_prop_count = 0;
1848         ffs->ms_os_descs_ext_prop_name_len = 0;
1849         ffs->ms_os_descs_ext_prop_data_len = 0;
1850 }
1851
1852
1853 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1854 {
1855         struct usb_gadget_strings **lang;
1856         int first_id;
1857
1858         ENTER();
1859
1860         if (WARN_ON(ffs->state != FFS_ACTIVE
1861                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1862                 return -EBADFD;
1863
1864         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1865         if (unlikely(first_id < 0))
1866                 return first_id;
1867
1868         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1869         if (unlikely(!ffs->ep0req))
1870                 return -ENOMEM;
1871         ffs->ep0req->complete = ffs_ep0_complete;
1872         ffs->ep0req->context = ffs;
1873
1874         lang = ffs->stringtabs;
1875         if (lang) {
1876                 for (; *lang; ++lang) {
1877                         struct usb_string *str = (*lang)->strings;
1878                         int id = first_id;
1879                         for (; str->s; ++id, ++str)
1880                                 str->id = id;
1881                 }
1882         }
1883
1884         ffs->gadget = cdev->gadget;
1885         ffs_data_get(ffs);
1886         return 0;
1887 }
1888
1889 static void functionfs_unbind(struct ffs_data *ffs)
1890 {
1891         ENTER();
1892
1893         if (!WARN_ON(!ffs->gadget)) {
1894                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1895                 ffs->ep0req = NULL;
1896                 ffs->gadget = NULL;
1897                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1898                 ffs_data_put(ffs);
1899         }
1900 }
1901
1902 static int ffs_epfiles_create(struct ffs_data *ffs)
1903 {
1904         struct ffs_epfile *epfile, *epfiles;
1905         unsigned i, count;
1906
1907         ENTER();
1908
1909         count = ffs->eps_count;
1910         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1911         if (!epfiles)
1912                 return -ENOMEM;
1913
1914         epfile = epfiles;
1915         for (i = 1; i <= count; ++i, ++epfile) {
1916                 epfile->ffs = ffs;
1917                 mutex_init(&epfile->mutex);
1918                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1919                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1920                 else
1921                         sprintf(epfile->name, "ep%u", i);
1922                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1923                                                  epfile,
1924                                                  &ffs_epfile_operations);
1925                 if (unlikely(!epfile->dentry)) {
1926                         ffs_epfiles_destroy(epfiles, i - 1);
1927                         return -ENOMEM;
1928                 }
1929         }
1930
1931         ffs->epfiles = epfiles;
1932         return 0;
1933 }
1934
1935 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1936 {
1937         struct ffs_epfile *epfile = epfiles;
1938
1939         ENTER();
1940
1941         for (; count; --count, ++epfile) {
1942                 BUG_ON(mutex_is_locked(&epfile->mutex));
1943                 if (epfile->dentry) {
1944                         d_delete(epfile->dentry);
1945                         dput(epfile->dentry);
1946                         epfile->dentry = NULL;
1947                 }
1948         }
1949
1950         kfree(epfiles);
1951 }
1952
1953 static void ffs_func_eps_disable(struct ffs_function *func)
1954 {
1955         struct ffs_ep *ep         = func->eps;
1956         struct ffs_epfile *epfile = func->ffs->epfiles;
1957         unsigned count            = func->ffs->eps_count;
1958         unsigned long flags;
1959
1960         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1961         while (count--) {
1962                 /* pending requests get nuked */
1963                 if (likely(ep->ep))
1964                         usb_ep_disable(ep->ep);
1965                 ++ep;
1966
1967                 if (epfile) {
1968                         epfile->ep = NULL;
1969                         __ffs_epfile_read_buffer_free(epfile);
1970                         ++epfile;
1971                 }
1972         }
1973         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1974 }
1975
1976 static int ffs_func_eps_enable(struct ffs_function *func)
1977 {
1978         struct ffs_data *ffs      = func->ffs;
1979         struct ffs_ep *ep         = func->eps;
1980         struct ffs_epfile *epfile = ffs->epfiles;
1981         unsigned count            = ffs->eps_count;
1982         unsigned long flags;
1983         int ret = 0;
1984
1985         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1986         while(count--) {
1987                 ep->ep->driver_data = ep;
1988
1989                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1990                 if (ret) {
1991                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1992                                         __func__, ep->ep->name, ret);
1993                         break;
1994                 }
1995
1996                 ret = usb_ep_enable(ep->ep);
1997                 if (likely(!ret)) {
1998                         epfile->ep = ep;
1999                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
2000                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
2001                 } else {
2002                         break;
2003                 }
2004
2005                 ++ep;
2006                 ++epfile;
2007         }
2008
2009         wake_up_interruptible(&ffs->wait);
2010         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2011
2012         return ret;
2013 }
2014
2015
2016 /* Parsing and building descriptors and strings *****************************/
2017
2018 /*
2019  * This validates if data pointed by data is a valid USB descriptor as
2020  * well as record how many interfaces, endpoints and strings are
2021  * required by given configuration.  Returns address after the
2022  * descriptor or NULL if data is invalid.
2023  */
2024
2025 enum ffs_entity_type {
2026         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
2027 };
2028
2029 enum ffs_os_desc_type {
2030         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
2031 };
2032
2033 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2034                                    u8 *valuep,
2035                                    struct usb_descriptor_header *desc,
2036                                    void *priv);
2037
2038 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2039                                     struct usb_os_desc_header *h, void *data,
2040                                     unsigned len, void *priv);
2041
2042 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2043                                            ffs_entity_callback entity,
2044                                            void *priv, int *current_class)
2045 {
2046         struct usb_descriptor_header *_ds = (void *)data;
2047         u8 length;
2048         int ret;
2049
2050         ENTER();
2051
2052         /* At least two bytes are required: length and type */
2053         if (len < 2) {
2054                 pr_vdebug("descriptor too short\n");
2055                 return -EINVAL;
2056         }
2057
2058         /* If we have at least as many bytes as the descriptor takes? */
2059         length = _ds->bLength;
2060         if (len < length) {
2061                 pr_vdebug("descriptor longer then available data\n");
2062                 return -EINVAL;
2063         }
2064
2065 #define __entity_check_INTERFACE(val)  1
2066 #define __entity_check_STRING(val)     (val)
2067 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2068 #define __entity(type, val) do {                                        \
2069                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2070                 if (unlikely(!__entity_check_ ##type(val))) {           \
2071                         pr_vdebug("invalid entity's value\n");          \
2072                         return -EINVAL;                                 \
2073                 }                                                       \
2074                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2075                 if (unlikely(ret < 0)) {                                \
2076                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2077                                  (val), ret);                           \
2078                         return ret;                                     \
2079                 }                                                       \
2080         } while (0)
2081
2082         /* Parse descriptor depending on type. */
2083         switch (_ds->bDescriptorType) {
2084         case USB_DT_DEVICE:
2085         case USB_DT_CONFIG:
2086         case USB_DT_STRING:
2087         case USB_DT_DEVICE_QUALIFIER:
2088                 /* function can't have any of those */
2089                 pr_vdebug("descriptor reserved for gadget: %d\n",
2090                       _ds->bDescriptorType);
2091                 return -EINVAL;
2092
2093         case USB_DT_INTERFACE: {
2094                 struct usb_interface_descriptor *ds = (void *)_ds;
2095                 pr_vdebug("interface descriptor\n");
2096                 if (length != sizeof *ds)
2097                         goto inv_length;
2098
2099                 __entity(INTERFACE, ds->bInterfaceNumber);
2100                 if (ds->iInterface)
2101                         __entity(STRING, ds->iInterface);
2102                 *current_class = ds->bInterfaceClass;
2103         }
2104                 break;
2105
2106         case USB_DT_ENDPOINT: {
2107                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2108                 pr_vdebug("endpoint descriptor\n");
2109                 if (length != USB_DT_ENDPOINT_SIZE &&
2110                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2111                         goto inv_length;
2112                 __entity(ENDPOINT, ds->bEndpointAddress);
2113         }
2114                 break;
2115
2116         case USB_TYPE_CLASS | 0x01:
2117                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2118                         pr_vdebug("hid descriptor\n");
2119                         if (length != sizeof(struct hid_descriptor))
2120                                 goto inv_length;
2121                         break;
2122                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2123                         pr_vdebug("ccid descriptor\n");
2124                         if (length != sizeof(struct ccid_descriptor))
2125                                 goto inv_length;
2126                         break;
2127                 } else {
2128                         pr_vdebug("unknown descriptor: %d for class %d\n",
2129                               _ds->bDescriptorType, *current_class);
2130                         return -EINVAL;
2131                 }
2132
2133         case USB_DT_OTG:
2134                 if (length != sizeof(struct usb_otg_descriptor))
2135                         goto inv_length;
2136                 break;
2137
2138         case USB_DT_INTERFACE_ASSOCIATION: {
2139                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2140                 pr_vdebug("interface association descriptor\n");
2141                 if (length != sizeof *ds)
2142                         goto inv_length;
2143                 if (ds->iFunction)
2144                         __entity(STRING, ds->iFunction);
2145         }
2146                 break;
2147
2148         case USB_DT_SS_ENDPOINT_COMP:
2149                 pr_vdebug("EP SS companion descriptor\n");
2150                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2151                         goto inv_length;
2152                 break;
2153
2154         case USB_DT_OTHER_SPEED_CONFIG:
2155         case USB_DT_INTERFACE_POWER:
2156         case USB_DT_DEBUG:
2157         case USB_DT_SECURITY:
2158         case USB_DT_CS_RADIO_CONTROL:
2159                 /* TODO */
2160                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2161                 return -EINVAL;
2162
2163         default:
2164                 /* We should never be here */
2165                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2166                 return -EINVAL;
2167
2168 inv_length:
2169                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2170                           _ds->bLength, _ds->bDescriptorType);
2171                 return -EINVAL;
2172         }
2173
2174 #undef __entity
2175 #undef __entity_check_DESCRIPTOR
2176 #undef __entity_check_INTERFACE
2177 #undef __entity_check_STRING
2178 #undef __entity_check_ENDPOINT
2179
2180         return length;
2181 }
2182
2183 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2184                                      ffs_entity_callback entity, void *priv)
2185 {
2186         const unsigned _len = len;
2187         unsigned long num = 0;
2188         int current_class = -1;
2189
2190         ENTER();
2191
2192         for (;;) {
2193                 int ret;
2194
2195                 if (num == count)
2196                         data = NULL;
2197
2198                 /* Record "descriptor" entity */
2199                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2200                 if (unlikely(ret < 0)) {
2201                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2202                                  num, ret);
2203                         return ret;
2204                 }
2205
2206                 if (!data)
2207                         return _len - len;
2208
2209                 ret = ffs_do_single_desc(data, len, entity, priv,
2210                         &current_class);
2211                 if (unlikely(ret < 0)) {
2212                         pr_debug("%s returns %d\n", __func__, ret);
2213                         return ret;
2214                 }
2215
2216                 len -= ret;
2217                 data += ret;
2218                 ++num;
2219         }
2220 }
2221
2222 static int __ffs_data_do_entity(enum ffs_entity_type type,
2223                                 u8 *valuep, struct usb_descriptor_header *desc,
2224                                 void *priv)
2225 {
2226         struct ffs_desc_helper *helper = priv;
2227         struct usb_endpoint_descriptor *d;
2228
2229         ENTER();
2230
2231         switch (type) {
2232         case FFS_DESCRIPTOR:
2233                 break;
2234
2235         case FFS_INTERFACE:
2236                 /*
2237                  * Interfaces are indexed from zero so if we
2238                  * encountered interface "n" then there are at least
2239                  * "n+1" interfaces.
2240                  */
2241                 if (*valuep >= helper->interfaces_count)
2242                         helper->interfaces_count = *valuep + 1;
2243                 break;
2244
2245         case FFS_STRING:
2246                 /*
2247                  * Strings are indexed from 1 (0 is reserved
2248                  * for languages list)
2249                  */
2250                 if (*valuep > helper->ffs->strings_count)
2251                         helper->ffs->strings_count = *valuep;
2252                 break;
2253
2254         case FFS_ENDPOINT:
2255                 d = (void *)desc;
2256                 helper->eps_count++;
2257                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2258                         return -EINVAL;
2259                 /* Check if descriptors for any speed were already parsed */
2260                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2261                         helper->ffs->eps_addrmap[helper->eps_count] =
2262                                 d->bEndpointAddress;
2263                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2264                                 d->bEndpointAddress)
2265                         return -EINVAL;
2266                 break;
2267         }
2268
2269         return 0;
2270 }
2271
2272 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2273                                    struct usb_os_desc_header *desc)
2274 {
2275         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2276         u16 w_index = le16_to_cpu(desc->wIndex);
2277
2278         if (bcd_version != 1) {
2279                 pr_vdebug("unsupported os descriptors version: %d",
2280                           bcd_version);
2281                 return -EINVAL;
2282         }
2283         switch (w_index) {
2284         case 0x4:
2285                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2286                 break;
2287         case 0x5:
2288                 *next_type = FFS_OS_DESC_EXT_PROP;
2289                 break;
2290         default:
2291                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2292                 return -EINVAL;
2293         }
2294
2295         return sizeof(*desc);
2296 }
2297
2298 /*
2299  * Process all extended compatibility/extended property descriptors
2300  * of a feature descriptor
2301  */
2302 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2303                                               enum ffs_os_desc_type type,
2304                                               u16 feature_count,
2305                                               ffs_os_desc_callback entity,
2306                                               void *priv,
2307                                               struct usb_os_desc_header *h)
2308 {
2309         int ret;
2310         const unsigned _len = len;
2311
2312         ENTER();
2313
2314         /* loop over all ext compat/ext prop descriptors */
2315         while (feature_count--) {
2316                 ret = entity(type, h, data, len, priv);
2317                 if (unlikely(ret < 0)) {
2318                         pr_debug("bad OS descriptor, type: %d\n", type);
2319                         return ret;
2320                 }
2321                 data += ret;
2322                 len -= ret;
2323         }
2324         return _len - len;
2325 }
2326
2327 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2328 static int __must_check ffs_do_os_descs(unsigned count,
2329                                         char *data, unsigned len,
2330                                         ffs_os_desc_callback entity, void *priv)
2331 {
2332         const unsigned _len = len;
2333         unsigned long num = 0;
2334
2335         ENTER();
2336
2337         for (num = 0; num < count; ++num) {
2338                 int ret;
2339                 enum ffs_os_desc_type type;
2340                 u16 feature_count;
2341                 struct usb_os_desc_header *desc = (void *)data;
2342
2343                 if (len < sizeof(*desc))
2344                         return -EINVAL;
2345
2346                 /*
2347                  * Record "descriptor" entity.
2348                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2349                  * Move the data pointer to the beginning of extended
2350                  * compatibilities proper or extended properties proper
2351                  * portions of the data
2352                  */
2353                 if (le32_to_cpu(desc->dwLength) > len)
2354                         return -EINVAL;
2355
2356                 ret = __ffs_do_os_desc_header(&type, desc);
2357                 if (unlikely(ret < 0)) {
2358                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2359                                  num, ret);
2360                         return ret;
2361                 }
2362                 /*
2363                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2364                  */
2365                 feature_count = le16_to_cpu(desc->wCount);
2366                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2367                     (feature_count > 255 || desc->Reserved))
2368                                 return -EINVAL;
2369                 len -= ret;
2370                 data += ret;
2371
2372                 /*
2373                  * Process all function/property descriptors
2374                  * of this Feature Descriptor
2375                  */
2376                 ret = ffs_do_single_os_desc(data, len, type,
2377                                             feature_count, entity, priv, desc);
2378                 if (unlikely(ret < 0)) {
2379                         pr_debug("%s returns %d\n", __func__, ret);
2380                         return ret;
2381                 }
2382
2383                 len -= ret;
2384                 data += ret;
2385         }
2386         return _len - len;
2387 }
2388
2389 /*
2390  * Validate contents of the buffer from userspace related to OS descriptors.
2391  */
2392 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2393                                  struct usb_os_desc_header *h, void *data,
2394                                  unsigned len, void *priv)
2395 {
2396         struct ffs_data *ffs = priv;
2397         u8 length;
2398
2399         ENTER();
2400
2401         switch (type) {
2402         case FFS_OS_DESC_EXT_COMPAT: {
2403                 struct usb_ext_compat_desc *d = data;
2404                 int i;
2405
2406                 if (len < sizeof(*d) ||
2407                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2408                         return -EINVAL;
2409                 if (d->Reserved1 != 1) {
2410                         /*
2411                          * According to the spec, Reserved1 must be set to 1
2412                          * but older kernels incorrectly rejected non-zero
2413                          * values.  We fix it here to avoid returning EINVAL
2414                          * in response to values we used to accept.
2415                          */
2416                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2417                         d->Reserved1 = 1;
2418                 }
2419                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2420                         if (d->Reserved2[i])
2421                                 return -EINVAL;
2422
2423                 length = sizeof(struct usb_ext_compat_desc);
2424         }
2425                 break;
2426         case FFS_OS_DESC_EXT_PROP: {
2427                 struct usb_ext_prop_desc *d = data;
2428                 u32 type, pdl;
2429                 u16 pnl;
2430
2431                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2432                         return -EINVAL;
2433                 length = le32_to_cpu(d->dwSize);
2434                 if (len < length)
2435                         return -EINVAL;
2436                 type = le32_to_cpu(d->dwPropertyDataType);
2437                 if (type < USB_EXT_PROP_UNICODE ||
2438                     type > USB_EXT_PROP_UNICODE_MULTI) {
2439                         pr_vdebug("unsupported os descriptor property type: %d",
2440                                   type);
2441                         return -EINVAL;
2442                 }
2443                 pnl = le16_to_cpu(d->wPropertyNameLength);
2444                 if (length < 14 + pnl) {
2445                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2446                                   length, pnl, type);
2447                         return -EINVAL;
2448                 }
2449                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2450                 if (length != 14 + pnl + pdl) {
2451                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2452                                   length, pnl, pdl, type);
2453                         return -EINVAL;
2454                 }
2455                 ++ffs->ms_os_descs_ext_prop_count;
2456                 /* property name reported to the host as "WCHAR"s */
2457                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2458                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2459         }
2460                 break;
2461         default:
2462                 pr_vdebug("unknown descriptor: %d\n", type);
2463                 return -EINVAL;
2464         }
2465         return length;
2466 }
2467
2468 static int __ffs_data_got_descs(struct ffs_data *ffs,
2469                                 char *const _data, size_t len)
2470 {
2471         char *data = _data, *raw_descs;
2472         unsigned os_descs_count = 0, counts[3], flags;
2473         int ret = -EINVAL, i;
2474         struct ffs_desc_helper helper;
2475
2476         ENTER();
2477
2478         if (get_unaligned_le32(data + 4) != len)
2479                 goto error;
2480
2481         switch (get_unaligned_le32(data)) {
2482         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2483                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2484                 data += 8;
2485                 len  -= 8;
2486                 break;
2487         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2488                 flags = get_unaligned_le32(data + 8);
2489                 ffs->user_flags = flags;
2490                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2491                               FUNCTIONFS_HAS_HS_DESC |
2492                               FUNCTIONFS_HAS_SS_DESC |
2493                               FUNCTIONFS_HAS_MS_OS_DESC |
2494                               FUNCTIONFS_VIRTUAL_ADDR |
2495                               FUNCTIONFS_EVENTFD |
2496                               FUNCTIONFS_ALL_CTRL_RECIP |
2497                               FUNCTIONFS_CONFIG0_SETUP)) {
2498                         ret = -ENOSYS;
2499                         goto error;
2500                 }
2501                 data += 12;
2502                 len  -= 12;
2503                 break;
2504         default:
2505                 goto error;
2506         }
2507
2508         if (flags & FUNCTIONFS_EVENTFD) {
2509                 if (len < 4)
2510                         goto error;
2511                 ffs->ffs_eventfd =
2512                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2513                 if (IS_ERR(ffs->ffs_eventfd)) {
2514                         ret = PTR_ERR(ffs->ffs_eventfd);
2515                         ffs->ffs_eventfd = NULL;
2516                         goto error;
2517                 }
2518                 data += 4;
2519                 len  -= 4;
2520         }
2521
2522         /* Read fs_count, hs_count and ss_count (if present) */
2523         for (i = 0; i < 3; ++i) {
2524                 if (!(flags & (1 << i))) {
2525                         counts[i] = 0;
2526                 } else if (len < 4) {
2527                         goto error;
2528                 } else {
2529                         counts[i] = get_unaligned_le32(data);
2530                         data += 4;
2531                         len  -= 4;
2532                 }
2533         }
2534         if (flags & (1 << i)) {
2535                 if (len < 4) {
2536                         goto error;
2537                 }
2538                 os_descs_count = get_unaligned_le32(data);
2539                 data += 4;
2540                 len -= 4;
2541         }
2542
2543         /* Read descriptors */
2544         raw_descs = data;
2545         helper.ffs = ffs;
2546         for (i = 0; i < 3; ++i) {
2547                 if (!counts[i])
2548                         continue;
2549                 helper.interfaces_count = 0;
2550                 helper.eps_count = 0;
2551                 ret = ffs_do_descs(counts[i], data, len,
2552                                    __ffs_data_do_entity, &helper);
2553                 if (ret < 0)
2554                         goto error;
2555                 if (!ffs->eps_count && !ffs->interfaces_count) {
2556                         ffs->eps_count = helper.eps_count;
2557                         ffs->interfaces_count = helper.interfaces_count;
2558                 } else {
2559                         if (ffs->eps_count != helper.eps_count) {
2560                                 ret = -EINVAL;
2561                                 goto error;
2562                         }
2563                         if (ffs->interfaces_count != helper.interfaces_count) {
2564                                 ret = -EINVAL;
2565                                 goto error;
2566                         }
2567                 }
2568                 data += ret;
2569                 len  -= ret;
2570         }
2571         if (os_descs_count) {
2572                 ret = ffs_do_os_descs(os_descs_count, data, len,
2573                                       __ffs_data_do_os_desc, ffs);
2574                 if (ret < 0)
2575                         goto error;
2576                 data += ret;
2577                 len -= ret;
2578         }
2579
2580         if (raw_descs == data || len) {
2581                 ret = -EINVAL;
2582                 goto error;
2583         }
2584
2585         ffs->raw_descs_data     = _data;
2586         ffs->raw_descs          = raw_descs;
2587         ffs->raw_descs_length   = data - raw_descs;
2588         ffs->fs_descs_count     = counts[0];
2589         ffs->hs_descs_count     = counts[1];
2590         ffs->ss_descs_count     = counts[2];
2591         ffs->ms_os_descs_count  = os_descs_count;
2592
2593         return 0;
2594
2595 error:
2596         kfree(_data);
2597         return ret;
2598 }
2599
2600 static int __ffs_data_got_strings(struct ffs_data *ffs,
2601                                   char *const _data, size_t len)
2602 {
2603         u32 str_count, needed_count, lang_count;
2604         struct usb_gadget_strings **stringtabs, *t;
2605         const char *data = _data;
2606         struct usb_string *s;
2607
2608         ENTER();
2609
2610         if (unlikely(len < 16 ||
2611                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2612                      get_unaligned_le32(data + 4) != len))
2613                 goto error;
2614         str_count  = get_unaligned_le32(data + 8);
2615         lang_count = get_unaligned_le32(data + 12);
2616
2617         /* if one is zero the other must be zero */
2618         if (unlikely(!str_count != !lang_count))
2619                 goto error;
2620
2621         /* Do we have at least as many strings as descriptors need? */
2622         needed_count = ffs->strings_count;
2623         if (unlikely(str_count < needed_count))
2624                 goto error;
2625
2626         /*
2627          * If we don't need any strings just return and free all
2628          * memory.
2629          */
2630         if (!needed_count) {
2631                 kfree(_data);
2632                 return 0;
2633         }
2634
2635         /* Allocate everything in one chunk so there's less maintenance. */
2636         {
2637                 unsigned i = 0;
2638                 vla_group(d);
2639                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2640                         lang_count + 1);
2641                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2642                 vla_item(d, struct usb_string, strings,
2643                         lang_count*(needed_count+1));
2644
2645                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2646
2647                 if (unlikely(!vlabuf)) {
2648                         kfree(_data);
2649                         return -ENOMEM;
2650                 }
2651
2652                 /* Initialize the VLA pointers */
2653                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2654                 t = vla_ptr(vlabuf, d, stringtab);
2655                 i = lang_count;
2656                 do {
2657                         *stringtabs++ = t++;
2658                 } while (--i);
2659                 *stringtabs = NULL;
2660
2661                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2662                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2663                 t = vla_ptr(vlabuf, d, stringtab);
2664                 s = vla_ptr(vlabuf, d, strings);
2665         }
2666
2667         /* For each language */
2668         data += 16;
2669         len -= 16;
2670
2671         do { /* lang_count > 0 so we can use do-while */
2672                 unsigned needed = needed_count;
2673
2674                 if (unlikely(len < 3))
2675                         goto error_free;
2676                 t->language = get_unaligned_le16(data);
2677                 t->strings  = s;
2678                 ++t;
2679
2680                 data += 2;
2681                 len -= 2;
2682
2683                 /* For each string */
2684                 do { /* str_count > 0 so we can use do-while */
2685                         size_t length = strnlen(data, len);
2686
2687                         if (unlikely(length == len))
2688                                 goto error_free;
2689
2690                         /*
2691                          * User may provide more strings then we need,
2692                          * if that's the case we simply ignore the
2693                          * rest
2694                          */
2695                         if (likely(needed)) {
2696                                 /*
2697                                  * s->id will be set while adding
2698                                  * function to configuration so for
2699                                  * now just leave garbage here.
2700                                  */
2701                                 s->s = data;
2702                                 --needed;
2703                                 ++s;
2704                         }
2705
2706                         data += length + 1;
2707                         len -= length + 1;
2708                 } while (--str_count);
2709
2710                 s->id = 0;   /* terminator */
2711                 s->s = NULL;
2712                 ++s;
2713
2714         } while (--lang_count);
2715
2716         /* Some garbage left? */
2717         if (unlikely(len))
2718                 goto error_free;
2719
2720         /* Done! */
2721         ffs->stringtabs = stringtabs;
2722         ffs->raw_strings = _data;
2723
2724         return 0;
2725
2726 error_free:
2727         kfree(stringtabs);
2728 error:
2729         kfree(_data);
2730         return -EINVAL;
2731 }
2732
2733
2734 /* Events handling and management *******************************************/
2735
2736 static void __ffs_event_add(struct ffs_data *ffs,
2737                             enum usb_functionfs_event_type type)
2738 {
2739         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2740         int neg = 0;
2741
2742         /*
2743          * Abort any unhandled setup
2744          *
2745          * We do not need to worry about some cmpxchg() changing value
2746          * of ffs->setup_state without holding the lock because when
2747          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2748          * the source does nothing.
2749          */
2750         if (ffs->setup_state == FFS_SETUP_PENDING)
2751                 ffs->setup_state = FFS_SETUP_CANCELLED;
2752
2753         /*
2754          * Logic of this function guarantees that there are at most four pending
2755          * evens on ffs->ev.types queue.  This is important because the queue
2756          * has space for four elements only and __ffs_ep0_read_events function
2757          * depends on that limit as well.  If more event types are added, those
2758          * limits have to be revisited or guaranteed to still hold.
2759          */
2760         switch (type) {
2761         case FUNCTIONFS_RESUME:
2762                 rem_type2 = FUNCTIONFS_SUSPEND;
2763                 fallthrough;
2764         case FUNCTIONFS_SUSPEND:
2765         case FUNCTIONFS_SETUP:
2766                 rem_type1 = type;
2767                 /* Discard all similar events */
2768                 break;
2769
2770         case FUNCTIONFS_BIND:
2771         case FUNCTIONFS_UNBIND:
2772         case FUNCTIONFS_DISABLE:
2773         case FUNCTIONFS_ENABLE:
2774                 /* Discard everything other then power management. */
2775                 rem_type1 = FUNCTIONFS_SUSPEND;
2776                 rem_type2 = FUNCTIONFS_RESUME;
2777                 neg = 1;
2778                 break;
2779
2780         default:
2781                 WARN(1, "%d: unknown event, this should not happen\n", type);
2782                 return;
2783         }
2784
2785         {
2786                 u8 *ev  = ffs->ev.types, *out = ev;
2787                 unsigned n = ffs->ev.count;
2788                 for (; n; --n, ++ev)
2789                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2790                                 *out++ = *ev;
2791                         else
2792                                 pr_vdebug("purging event %d\n", *ev);
2793                 ffs->ev.count = out - ffs->ev.types;
2794         }
2795
2796         pr_vdebug("adding event %d\n", type);
2797         ffs->ev.types[ffs->ev.count++] = type;
2798         wake_up_locked(&ffs->ev.waitq);
2799         if (ffs->ffs_eventfd)
2800                 eventfd_signal(ffs->ffs_eventfd, 1);
2801 }
2802
2803 static void ffs_event_add(struct ffs_data *ffs,
2804                           enum usb_functionfs_event_type type)
2805 {
2806         unsigned long flags;
2807         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2808         __ffs_event_add(ffs, type);
2809         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2810 }
2811
2812 /* Bind/unbind USB function hooks *******************************************/
2813
2814 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2815 {
2816         int i;
2817
2818         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2819                 if (ffs->eps_addrmap[i] == endpoint_address)
2820                         return i;
2821         return -ENOENT;
2822 }
2823
2824 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2825                                     struct usb_descriptor_header *desc,
2826                                     void *priv)
2827 {
2828         struct usb_endpoint_descriptor *ds = (void *)desc;
2829         struct ffs_function *func = priv;
2830         struct ffs_ep *ffs_ep;
2831         unsigned ep_desc_id;
2832         int idx;
2833         static const char *speed_names[] = { "full", "high", "super" };
2834
2835         if (type != FFS_DESCRIPTOR)
2836                 return 0;
2837
2838         /*
2839          * If ss_descriptors is not NULL, we are reading super speed
2840          * descriptors; if hs_descriptors is not NULL, we are reading high
2841          * speed descriptors; otherwise, we are reading full speed
2842          * descriptors.
2843          */
2844         if (func->function.ss_descriptors) {
2845                 ep_desc_id = 2;
2846                 func->function.ss_descriptors[(long)valuep] = desc;
2847         } else if (func->function.hs_descriptors) {
2848                 ep_desc_id = 1;
2849                 func->function.hs_descriptors[(long)valuep] = desc;
2850         } else {
2851                 ep_desc_id = 0;
2852                 func->function.fs_descriptors[(long)valuep]    = desc;
2853         }
2854
2855         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2856                 return 0;
2857
2858         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2859         if (idx < 0)
2860                 return idx;
2861
2862         ffs_ep = func->eps + idx;
2863
2864         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2865                 pr_err("two %sspeed descriptors for EP %d\n",
2866                           speed_names[ep_desc_id],
2867                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2868                 return -EINVAL;
2869         }
2870         ffs_ep->descs[ep_desc_id] = ds;
2871
2872         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2873         if (ffs_ep->ep) {
2874                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2875                 if (!ds->wMaxPacketSize)
2876                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2877         } else {
2878                 struct usb_request *req;
2879                 struct usb_ep *ep;
2880                 u8 bEndpointAddress;
2881                 u16 wMaxPacketSize;
2882
2883                 /*
2884                  * We back up bEndpointAddress because autoconfig overwrites
2885                  * it with physical endpoint address.
2886                  */
2887                 bEndpointAddress = ds->bEndpointAddress;
2888                 /*
2889                  * We back up wMaxPacketSize because autoconfig treats
2890                  * endpoint descriptors as if they were full speed.
2891                  */
2892                 wMaxPacketSize = ds->wMaxPacketSize;
2893                 pr_vdebug("autoconfig\n");
2894                 ep = usb_ep_autoconfig(func->gadget, ds);
2895                 if (unlikely(!ep))
2896                         return -ENOTSUPP;
2897                 ep->driver_data = func->eps + idx;
2898
2899                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2900                 if (unlikely(!req))
2901                         return -ENOMEM;
2902
2903                 ffs_ep->ep  = ep;
2904                 ffs_ep->req = req;
2905                 func->eps_revmap[ds->bEndpointAddress &
2906                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2907                 /*
2908                  * If we use virtual address mapping, we restore
2909                  * original bEndpointAddress value.
2910                  */
2911                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2912                         ds->bEndpointAddress = bEndpointAddress;
2913                 /*
2914                  * Restore wMaxPacketSize which was potentially
2915                  * overwritten by autoconfig.
2916                  */
2917                 ds->wMaxPacketSize = wMaxPacketSize;
2918         }
2919         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2920
2921         return 0;
2922 }
2923
2924 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2925                                    struct usb_descriptor_header *desc,
2926                                    void *priv)
2927 {
2928         struct ffs_function *func = priv;
2929         unsigned idx;
2930         u8 newValue;
2931
2932         switch (type) {
2933         default:
2934         case FFS_DESCRIPTOR:
2935                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2936                 return 0;
2937
2938         case FFS_INTERFACE:
2939                 idx = *valuep;
2940                 if (func->interfaces_nums[idx] < 0) {
2941                         int id = usb_interface_id(func->conf, &func->function);
2942                         if (unlikely(id < 0))
2943                                 return id;
2944                         func->interfaces_nums[idx] = id;
2945                 }
2946                 newValue = func->interfaces_nums[idx];
2947                 break;
2948
2949         case FFS_STRING:
2950                 /* String' IDs are allocated when fsf_data is bound to cdev */
2951                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2952                 break;
2953
2954         case FFS_ENDPOINT:
2955                 /*
2956                  * USB_DT_ENDPOINT are handled in
2957                  * __ffs_func_bind_do_descs().
2958                  */
2959                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2960                         return 0;
2961
2962                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2963                 if (unlikely(!func->eps[idx].ep))
2964                         return -EINVAL;
2965
2966                 {
2967                         struct usb_endpoint_descriptor **descs;
2968                         descs = func->eps[idx].descs;
2969                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2970                 }
2971                 break;
2972         }
2973
2974         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2975         *valuep = newValue;
2976         return 0;
2977 }
2978
2979 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2980                                       struct usb_os_desc_header *h, void *data,
2981                                       unsigned len, void *priv)
2982 {
2983         struct ffs_function *func = priv;
2984         u8 length = 0;
2985
2986         switch (type) {
2987         case FFS_OS_DESC_EXT_COMPAT: {
2988                 struct usb_ext_compat_desc *desc = data;
2989                 struct usb_os_desc_table *t;
2990
2991                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2992                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2993                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2994                        ARRAY_SIZE(desc->CompatibleID) +
2995                        ARRAY_SIZE(desc->SubCompatibleID));
2996                 length = sizeof(*desc);
2997         }
2998                 break;
2999         case FFS_OS_DESC_EXT_PROP: {
3000                 struct usb_ext_prop_desc *desc = data;
3001                 struct usb_os_desc_table *t;
3002                 struct usb_os_desc_ext_prop *ext_prop;
3003                 char *ext_prop_name;
3004                 char *ext_prop_data;
3005
3006                 t = &func->function.os_desc_table[h->interface];
3007                 t->if_id = func->interfaces_nums[h->interface];
3008
3009                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
3010                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
3011
3012                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
3013                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
3014                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
3015                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
3016                 length = ext_prop->name_len + ext_prop->data_len + 14;
3017
3018                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
3019                 func->ffs->ms_os_descs_ext_prop_name_avail +=
3020                         ext_prop->name_len;
3021
3022                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
3023                 func->ffs->ms_os_descs_ext_prop_data_avail +=
3024                         ext_prop->data_len;
3025                 memcpy(ext_prop_data,
3026                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
3027                        ext_prop->data_len);
3028                 /* unicode data reported to the host as "WCHAR"s */
3029                 switch (ext_prop->type) {
3030                 case USB_EXT_PROP_UNICODE:
3031                 case USB_EXT_PROP_UNICODE_ENV:
3032                 case USB_EXT_PROP_UNICODE_LINK:
3033                 case USB_EXT_PROP_UNICODE_MULTI:
3034                         ext_prop->data_len *= 2;
3035                         break;
3036                 }
3037                 ext_prop->data = ext_prop_data;
3038
3039                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3040                        ext_prop->name_len);
3041                 /* property name reported to the host as "WCHAR"s */
3042                 ext_prop->name_len *= 2;
3043                 ext_prop->name = ext_prop_name;
3044
3045                 t->os_desc->ext_prop_len +=
3046                         ext_prop->name_len + ext_prop->data_len + 14;
3047                 ++t->os_desc->ext_prop_count;
3048                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3049         }
3050                 break;
3051         default:
3052                 pr_vdebug("unknown descriptor: %d\n", type);
3053         }
3054
3055         return length;
3056 }
3057
3058 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3059                                                 struct usb_configuration *c)
3060 {
3061         struct ffs_function *func = ffs_func_from_usb(f);
3062         struct f_fs_opts *ffs_opts =
3063                 container_of(f->fi, struct f_fs_opts, func_inst);
3064         int ret;
3065
3066         ENTER();
3067
3068         /*
3069          * Legacy gadget triggers binding in functionfs_ready_callback,
3070          * which already uses locking; taking the same lock here would
3071          * cause a deadlock.
3072          *
3073          * Configfs-enabled gadgets however do need ffs_dev_lock.
3074          */
3075         if (!ffs_opts->no_configfs)
3076                 ffs_dev_lock();
3077         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3078         func->ffs = ffs_opts->dev->ffs_data;
3079         if (!ffs_opts->no_configfs)
3080                 ffs_dev_unlock();
3081         if (ret)
3082                 return ERR_PTR(ret);
3083
3084         func->conf = c;
3085         func->gadget = c->cdev->gadget;
3086
3087         /*
3088          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3089          * configurations are bound in sequence with list_for_each_entry,
3090          * in each configuration its functions are bound in sequence
3091          * with list_for_each_entry, so we assume no race condition
3092          * with regard to ffs_opts->bound access
3093          */
3094         if (!ffs_opts->refcnt) {
3095                 ret = functionfs_bind(func->ffs, c->cdev);
3096                 if (ret)
3097                         return ERR_PTR(ret);
3098         }
3099         ffs_opts->refcnt++;
3100         func->function.strings = func->ffs->stringtabs;
3101
3102         return ffs_opts;
3103 }
3104
3105 static int _ffs_func_bind(struct usb_configuration *c,
3106                           struct usb_function *f)
3107 {
3108         struct ffs_function *func = ffs_func_from_usb(f);
3109         struct ffs_data *ffs = func->ffs;
3110
3111         const int full = !!func->ffs->fs_descs_count;
3112         const int high = !!func->ffs->hs_descs_count;
3113         const int super = !!func->ffs->ss_descs_count;
3114
3115         int fs_len, hs_len, ss_len, ret, i;
3116         struct ffs_ep *eps_ptr;
3117
3118         /* Make it a single chunk, less management later on */
3119         vla_group(d);
3120         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3121         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3122                 full ? ffs->fs_descs_count + 1 : 0);
3123         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3124                 high ? ffs->hs_descs_count + 1 : 0);
3125         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3126                 super ? ffs->ss_descs_count + 1 : 0);
3127         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3128         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3129                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3130         vla_item_with_sz(d, char[16], ext_compat,
3131                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3132         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3133                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3134         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3135                          ffs->ms_os_descs_ext_prop_count);
3136         vla_item_with_sz(d, char, ext_prop_name,
3137                          ffs->ms_os_descs_ext_prop_name_len);
3138         vla_item_with_sz(d, char, ext_prop_data,
3139                          ffs->ms_os_descs_ext_prop_data_len);
3140         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3141         char *vlabuf;
3142
3143         ENTER();
3144
3145         /* Has descriptors only for speeds gadget does not support */
3146         if (unlikely(!(full | high | super)))
3147                 return -ENOTSUPP;
3148
3149         /* Allocate a single chunk, less management later on */
3150         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3151         if (unlikely(!vlabuf))
3152                 return -ENOMEM;
3153
3154         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3155         ffs->ms_os_descs_ext_prop_name_avail =
3156                 vla_ptr(vlabuf, d, ext_prop_name);
3157         ffs->ms_os_descs_ext_prop_data_avail =
3158                 vla_ptr(vlabuf, d, ext_prop_data);
3159
3160         /* Copy descriptors  */
3161         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3162                ffs->raw_descs_length);
3163
3164         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3165         eps_ptr = vla_ptr(vlabuf, d, eps);
3166         for (i = 0; i < ffs->eps_count; i++)
3167                 eps_ptr[i].num = -1;
3168
3169         /* Save pointers
3170          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3171         */
3172         func->eps             = vla_ptr(vlabuf, d, eps);
3173         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3174
3175         /*
3176          * Go through all the endpoint descriptors and allocate
3177          * endpoints first, so that later we can rewrite the endpoint
3178          * numbers without worrying that it may be described later on.
3179          */
3180         if (likely(full)) {
3181                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3182                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3183                                       vla_ptr(vlabuf, d, raw_descs),
3184                                       d_raw_descs__sz,
3185                                       __ffs_func_bind_do_descs, func);
3186                 if (unlikely(fs_len < 0)) {
3187                         ret = fs_len;
3188                         goto error;
3189                 }
3190         } else {
3191                 fs_len = 0;
3192         }
3193
3194         if (likely(high)) {
3195                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3196                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3197                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3198                                       d_raw_descs__sz - fs_len,
3199                                       __ffs_func_bind_do_descs, func);
3200                 if (unlikely(hs_len < 0)) {
3201                         ret = hs_len;
3202                         goto error;
3203                 }
3204         } else {
3205                 hs_len = 0;
3206         }
3207
3208         if (likely(super)) {
3209                 func->function.ss_descriptors = func->function.ssp_descriptors =
3210                         vla_ptr(vlabuf, d, ss_descs);
3211                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3212                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3213                                 d_raw_descs__sz - fs_len - hs_len,
3214                                 __ffs_func_bind_do_descs, func);
3215                 if (unlikely(ss_len < 0)) {
3216                         ret = ss_len;
3217                         goto error;
3218                 }
3219         } else {
3220                 ss_len = 0;
3221         }
3222
3223         /*
3224          * Now handle interface numbers allocation and interface and
3225          * endpoint numbers rewriting.  We can do that in one go
3226          * now.
3227          */
3228         ret = ffs_do_descs(ffs->fs_descs_count +
3229                            (high ? ffs->hs_descs_count : 0) +
3230                            (super ? ffs->ss_descs_count : 0),
3231                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3232                            __ffs_func_bind_do_nums, func);
3233         if (unlikely(ret < 0))
3234                 goto error;
3235
3236         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3237         if (c->cdev->use_os_string) {
3238                 for (i = 0; i < ffs->interfaces_count; ++i) {
3239                         struct usb_os_desc *desc;
3240
3241                         desc = func->function.os_desc_table[i].os_desc =
3242                                 vla_ptr(vlabuf, d, os_desc) +
3243                                 i * sizeof(struct usb_os_desc);
3244                         desc->ext_compat_id =
3245                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3246                         INIT_LIST_HEAD(&desc->ext_prop);
3247                 }
3248                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3249                                       vla_ptr(vlabuf, d, raw_descs) +
3250                                       fs_len + hs_len + ss_len,
3251                                       d_raw_descs__sz - fs_len - hs_len -
3252                                       ss_len,
3253                                       __ffs_func_bind_do_os_desc, func);
3254                 if (unlikely(ret < 0))
3255                         goto error;
3256         }
3257         func->function.os_desc_n =
3258                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3259
3260         /* And we're done */
3261         ffs_event_add(ffs, FUNCTIONFS_BIND);
3262         return 0;
3263
3264 error:
3265         /* XXX Do we need to release all claimed endpoints here? */
3266         return ret;
3267 }
3268
3269 static int ffs_func_bind(struct usb_configuration *c,
3270                          struct usb_function *f)
3271 {
3272         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3273         struct ffs_function *func = ffs_func_from_usb(f);
3274         int ret;
3275
3276         if (IS_ERR(ffs_opts))
3277                 return PTR_ERR(ffs_opts);
3278
3279         ret = _ffs_func_bind(c, f);
3280         if (ret && !--ffs_opts->refcnt)
3281                 functionfs_unbind(func->ffs);
3282
3283         return ret;
3284 }
3285
3286
3287 /* Other USB function hooks *************************************************/
3288
3289 static void ffs_reset_work(struct work_struct *work)
3290 {
3291         struct ffs_data *ffs = container_of(work,
3292                 struct ffs_data, reset_work);
3293         ffs_data_reset(ffs);
3294 }
3295
3296 static int ffs_func_set_alt(struct usb_function *f,
3297                             unsigned interface, unsigned alt)
3298 {
3299         struct ffs_function *func = ffs_func_from_usb(f);
3300         struct ffs_data *ffs = func->ffs;
3301         int ret = 0, intf;
3302
3303         if (alt != (unsigned)-1) {
3304                 intf = ffs_func_revmap_intf(func, interface);
3305                 if (unlikely(intf < 0))
3306                         return intf;
3307         }
3308
3309         if (ffs->func)
3310                 ffs_func_eps_disable(ffs->func);
3311
3312         if (ffs->state == FFS_DEACTIVATED) {
3313                 ffs->state = FFS_CLOSING;
3314                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3315                 schedule_work(&ffs->reset_work);
3316                 return -ENODEV;
3317         }
3318
3319         if (ffs->state != FFS_ACTIVE)
3320                 return -ENODEV;
3321
3322         if (alt == (unsigned)-1) {
3323                 ffs->func = NULL;
3324                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3325                 return 0;
3326         }
3327
3328         ffs->func = func;
3329         ret = ffs_func_eps_enable(func);
3330         if (likely(ret >= 0))
3331                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3332         return ret;
3333 }
3334
3335 static void ffs_func_disable(struct usb_function *f)
3336 {
3337         ffs_func_set_alt(f, 0, (unsigned)-1);
3338 }
3339
3340 static int ffs_func_setup(struct usb_function *f,
3341                           const struct usb_ctrlrequest *creq)
3342 {
3343         struct ffs_function *func = ffs_func_from_usb(f);
3344         struct ffs_data *ffs = func->ffs;
3345         unsigned long flags;
3346         int ret;
3347
3348         ENTER();
3349
3350         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3351         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3352         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3353         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3354         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3355
3356         /*
3357          * Most requests directed to interface go through here
3358          * (notable exceptions are set/get interface) so we need to
3359          * handle them.  All other either handled by composite or
3360          * passed to usb_configuration->setup() (if one is set).  No
3361          * matter, we will handle requests directed to endpoint here
3362          * as well (as it's straightforward).  Other request recipient
3363          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3364          * is being used.
3365          */
3366         if (ffs->state != FFS_ACTIVE)
3367                 return -ENODEV;
3368
3369         switch (creq->bRequestType & USB_RECIP_MASK) {
3370         case USB_RECIP_INTERFACE:
3371                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3372                 if (unlikely(ret < 0))
3373                         return ret;
3374                 break;
3375
3376         case USB_RECIP_ENDPOINT:
3377                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3378                 if (unlikely(ret < 0))
3379                         return ret;
3380                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3381                         ret = func->ffs->eps_addrmap[ret];
3382                 break;
3383
3384         default:
3385                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3386                         ret = le16_to_cpu(creq->wIndex);
3387                 else
3388                         return -EOPNOTSUPP;
3389         }
3390
3391         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3392         ffs->ev.setup = *creq;
3393         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3394         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3395         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3396
3397         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3398 }
3399
3400 static bool ffs_func_req_match(struct usb_function *f,
3401                                const struct usb_ctrlrequest *creq,
3402                                bool config0)
3403 {
3404         struct ffs_function *func = ffs_func_from_usb(f);
3405
3406         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3407                 return false;
3408
3409         switch (creq->bRequestType & USB_RECIP_MASK) {
3410         case USB_RECIP_INTERFACE:
3411                 return (ffs_func_revmap_intf(func,
3412                                              le16_to_cpu(creq->wIndex)) >= 0);
3413         case USB_RECIP_ENDPOINT:
3414                 return (ffs_func_revmap_ep(func,
3415                                            le16_to_cpu(creq->wIndex)) >= 0);
3416         default:
3417                 return (bool) (func->ffs->user_flags &
3418                                FUNCTIONFS_ALL_CTRL_RECIP);
3419         }
3420 }
3421
3422 static void ffs_func_suspend(struct usb_function *f)
3423 {
3424         ENTER();
3425         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3426 }
3427
3428 static void ffs_func_resume(struct usb_function *f)
3429 {
3430         ENTER();
3431         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3432 }
3433
3434
3435 /* Endpoint and interface numbers reverse mapping ***************************/
3436
3437 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3438 {
3439         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3440         return num ? num : -EDOM;
3441 }
3442
3443 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3444 {
3445         short *nums = func->interfaces_nums;
3446         unsigned count = func->ffs->interfaces_count;
3447
3448         for (; count; --count, ++nums) {
3449                 if (*nums >= 0 && *nums == intf)
3450                         return nums - func->interfaces_nums;
3451         }
3452
3453         return -EDOM;
3454 }
3455
3456
3457 /* Devices management *******************************************************/
3458
3459 static LIST_HEAD(ffs_devices);
3460
3461 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3462 {
3463         struct ffs_dev *dev;
3464
3465         if (!name)
3466                 return NULL;
3467
3468         list_for_each_entry(dev, &ffs_devices, entry) {
3469                 if (strcmp(dev->name, name) == 0)
3470                         return dev;
3471         }
3472
3473         return NULL;
3474 }
3475
3476 /*
3477  * ffs_lock must be taken by the caller of this function
3478  */
3479 static struct ffs_dev *_ffs_get_single_dev(void)
3480 {
3481         struct ffs_dev *dev;
3482
3483         if (list_is_singular(&ffs_devices)) {
3484                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3485                 if (dev->single)
3486                         return dev;
3487         }
3488
3489         return NULL;
3490 }
3491
3492 /*
3493  * ffs_lock must be taken by the caller of this function
3494  */
3495 static struct ffs_dev *_ffs_find_dev(const char *name)
3496 {
3497         struct ffs_dev *dev;
3498
3499         dev = _ffs_get_single_dev();
3500         if (dev)
3501                 return dev;
3502
3503         return _ffs_do_find_dev(name);
3504 }
3505
3506 /* Configfs support *********************************************************/
3507
3508 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3509 {
3510         return container_of(to_config_group(item), struct f_fs_opts,
3511                             func_inst.group);
3512 }
3513
3514 static void ffs_attr_release(struct config_item *item)
3515 {
3516         struct f_fs_opts *opts = to_ffs_opts(item);
3517
3518         usb_put_function_instance(&opts->func_inst);
3519 }
3520
3521 static struct configfs_item_operations ffs_item_ops = {
3522         .release        = ffs_attr_release,
3523 };
3524
3525 static const struct config_item_type ffs_func_type = {
3526         .ct_item_ops    = &ffs_item_ops,
3527         .ct_owner       = THIS_MODULE,
3528 };
3529
3530
3531 /* Function registration interface ******************************************/
3532
3533 static void ffs_free_inst(struct usb_function_instance *f)
3534 {
3535         struct f_fs_opts *opts;
3536
3537         opts = to_f_fs_opts(f);
3538         ffs_dev_lock();
3539         _ffs_free_dev(opts->dev);
3540         ffs_dev_unlock();
3541         kfree(opts);
3542 }
3543
3544 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3545 {
3546         if (strlen(name) >= sizeof_field(struct ffs_dev, name))
3547                 return -ENAMETOOLONG;
3548         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3549 }
3550
3551 static struct usb_function_instance *ffs_alloc_inst(void)
3552 {
3553         struct f_fs_opts *opts;
3554         struct ffs_dev *dev;
3555
3556         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3557         if (!opts)
3558                 return ERR_PTR(-ENOMEM);
3559
3560         opts->func_inst.set_inst_name = ffs_set_inst_name;
3561         opts->func_inst.free_func_inst = ffs_free_inst;
3562         ffs_dev_lock();
3563         dev = _ffs_alloc_dev();
3564         ffs_dev_unlock();
3565         if (IS_ERR(dev)) {
3566                 kfree(opts);
3567                 return ERR_CAST(dev);
3568         }
3569         opts->dev = dev;
3570         dev->opts = opts;
3571
3572         config_group_init_type_name(&opts->func_inst.group, "",
3573                                     &ffs_func_type);
3574         return &opts->func_inst;
3575 }
3576
3577 static void ffs_free(struct usb_function *f)
3578 {
3579         kfree(ffs_func_from_usb(f));
3580 }
3581
3582 static void ffs_func_unbind(struct usb_configuration *c,
3583                             struct usb_function *f)
3584 {
3585         struct ffs_function *func = ffs_func_from_usb(f);
3586         struct ffs_data *ffs = func->ffs;
3587         struct f_fs_opts *opts =
3588                 container_of(f->fi, struct f_fs_opts, func_inst);
3589         struct ffs_ep *ep = func->eps;
3590         unsigned count = ffs->eps_count;
3591         unsigned long flags;
3592
3593         ENTER();
3594         if (ffs->func == func) {
3595                 ffs_func_eps_disable(func);
3596                 ffs->func = NULL;
3597         }
3598
3599         if (!--opts->refcnt)
3600                 functionfs_unbind(ffs);
3601
3602         /* cleanup after autoconfig */
3603         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3604         while (count--) {
3605                 if (ep->ep && ep->req)
3606                         usb_ep_free_request(ep->ep, ep->req);
3607                 ep->req = NULL;
3608                 ++ep;
3609         }
3610         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3611         kfree(func->eps);
3612         func->eps = NULL;
3613         /*
3614          * eps, descriptors and interfaces_nums are allocated in the
3615          * same chunk so only one free is required.
3616          */
3617         func->function.fs_descriptors = NULL;
3618         func->function.hs_descriptors = NULL;
3619         func->function.ss_descriptors = NULL;
3620         func->function.ssp_descriptors = NULL;
3621         func->interfaces_nums = NULL;
3622
3623         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3624 }
3625
3626 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3627 {
3628         struct ffs_function *func;
3629
3630         ENTER();
3631
3632         func = kzalloc(sizeof(*func), GFP_KERNEL);
3633         if (unlikely(!func))
3634                 return ERR_PTR(-ENOMEM);
3635
3636         func->function.name    = "Function FS Gadget";
3637
3638         func->function.bind    = ffs_func_bind;
3639         func->function.unbind  = ffs_func_unbind;
3640         func->function.set_alt = ffs_func_set_alt;
3641         func->function.disable = ffs_func_disable;
3642         func->function.setup   = ffs_func_setup;
3643         func->function.req_match = ffs_func_req_match;
3644         func->function.suspend = ffs_func_suspend;
3645         func->function.resume  = ffs_func_resume;
3646         func->function.free_func = ffs_free;
3647
3648         return &func->function;
3649 }
3650
3651 /*
3652  * ffs_lock must be taken by the caller of this function
3653  */
3654 static struct ffs_dev *_ffs_alloc_dev(void)
3655 {
3656         struct ffs_dev *dev;
3657         int ret;
3658
3659         if (_ffs_get_single_dev())
3660                         return ERR_PTR(-EBUSY);
3661
3662         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3663         if (!dev)
3664                 return ERR_PTR(-ENOMEM);
3665
3666         if (list_empty(&ffs_devices)) {
3667                 ret = functionfs_init();
3668                 if (ret) {
3669                         kfree(dev);
3670                         return ERR_PTR(ret);
3671                 }
3672         }
3673
3674         list_add(&dev->entry, &ffs_devices);
3675
3676         return dev;
3677 }
3678
3679 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3680 {
3681         struct ffs_dev *existing;
3682         int ret = 0;
3683
3684         ffs_dev_lock();
3685
3686         existing = _ffs_do_find_dev(name);
3687         if (!existing)
3688                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3689         else if (existing != dev)
3690                 ret = -EBUSY;
3691
3692         ffs_dev_unlock();
3693
3694         return ret;
3695 }
3696 EXPORT_SYMBOL_GPL(ffs_name_dev);
3697
3698 int ffs_single_dev(struct ffs_dev *dev)
3699 {
3700         int ret;
3701
3702         ret = 0;
3703         ffs_dev_lock();
3704
3705         if (!list_is_singular(&ffs_devices))
3706                 ret = -EBUSY;
3707         else
3708                 dev->single = true;
3709
3710         ffs_dev_unlock();
3711         return ret;
3712 }
3713 EXPORT_SYMBOL_GPL(ffs_single_dev);
3714
3715 /*
3716  * ffs_lock must be taken by the caller of this function
3717  */
3718 static void _ffs_free_dev(struct ffs_dev *dev)
3719 {
3720         list_del(&dev->entry);
3721
3722         /* Clear the private_data pointer to stop incorrect dev access */
3723         if (dev->ffs_data)
3724                 dev->ffs_data->private_data = NULL;
3725
3726         kfree(dev);
3727         if (list_empty(&ffs_devices))
3728                 functionfs_cleanup();
3729 }
3730
3731 static void *ffs_acquire_dev(const char *dev_name)
3732 {
3733         struct ffs_dev *ffs_dev;
3734
3735         ENTER();
3736         ffs_dev_lock();
3737
3738         ffs_dev = _ffs_find_dev(dev_name);
3739         if (!ffs_dev)
3740                 ffs_dev = ERR_PTR(-ENOENT);
3741         else if (ffs_dev->mounted)
3742                 ffs_dev = ERR_PTR(-EBUSY);
3743         else if (ffs_dev->ffs_acquire_dev_callback &&
3744             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3745                 ffs_dev = ERR_PTR(-ENOENT);
3746         else
3747                 ffs_dev->mounted = true;
3748
3749         ffs_dev_unlock();
3750         return ffs_dev;
3751 }
3752
3753 static void ffs_release_dev(struct ffs_data *ffs_data)
3754 {
3755         struct ffs_dev *ffs_dev;
3756
3757         ENTER();
3758         ffs_dev_lock();
3759
3760         ffs_dev = ffs_data->private_data;
3761         if (ffs_dev) {
3762                 ffs_dev->mounted = false;
3763
3764                 if (ffs_dev->ffs_release_dev_callback)
3765                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3766         }
3767
3768         ffs_dev_unlock();
3769 }
3770
3771 static int ffs_ready(struct ffs_data *ffs)
3772 {
3773         struct ffs_dev *ffs_obj;
3774         int ret = 0;
3775
3776         ENTER();
3777         ffs_dev_lock();
3778
3779         ffs_obj = ffs->private_data;
3780         if (!ffs_obj) {
3781                 ret = -EINVAL;
3782                 goto done;
3783         }
3784         if (WARN_ON(ffs_obj->desc_ready)) {
3785                 ret = -EBUSY;
3786                 goto done;
3787         }
3788
3789         ffs_obj->desc_ready = true;
3790         ffs_obj->ffs_data = ffs;
3791
3792         if (ffs_obj->ffs_ready_callback) {
3793                 ret = ffs_obj->ffs_ready_callback(ffs);
3794                 if (ret)
3795                         goto done;
3796         }
3797
3798         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3799 done:
3800         ffs_dev_unlock();
3801         return ret;
3802 }
3803
3804 static void ffs_closed(struct ffs_data *ffs)
3805 {
3806         struct ffs_dev *ffs_obj;
3807         struct f_fs_opts *opts;
3808         struct config_item *ci;
3809
3810         ENTER();
3811         ffs_dev_lock();
3812
3813         ffs_obj = ffs->private_data;
3814         if (!ffs_obj)
3815                 goto done;
3816
3817         ffs_obj->desc_ready = false;
3818         ffs_obj->ffs_data = NULL;
3819
3820         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3821             ffs_obj->ffs_closed_callback)
3822                 ffs_obj->ffs_closed_callback(ffs);
3823
3824         if (ffs_obj->opts)
3825                 opts = ffs_obj->opts;
3826         else
3827                 goto done;
3828
3829         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3830             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3831                 goto done;
3832
3833         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3834         ffs_dev_unlock();
3835
3836         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3837                 unregister_gadget_item(ci);
3838         return;
3839 done:
3840         ffs_dev_unlock();
3841 }
3842
3843 /* Misc helper functions ****************************************************/
3844
3845 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3846 {
3847         return nonblock
3848                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3849                 : mutex_lock_interruptible(mutex);
3850 }
3851
3852 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3853 {
3854         char *data;
3855
3856         if (unlikely(!len))
3857                 return NULL;
3858
3859         data = kmalloc(len, GFP_KERNEL);
3860         if (unlikely(!data))
3861                 return ERR_PTR(-ENOMEM);
3862
3863         if (unlikely(copy_from_user(data, buf, len))) {
3864                 kfree(data);
3865                 return ERR_PTR(-EFAULT);
3866         }
3867
3868         pr_vdebug("Buffer from user space:\n");
3869         ffs_dump_mem("", data, len);
3870
3871         return data;
3872 }
3873
3874 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3875 MODULE_LICENSE("GPL");
3876 MODULE_AUTHOR("Michal Nazarewicz");