drivers/usb/gadget/f_fs.c

   1 /*
   2  * f_fs.c -- user mode file system API for USB composite function controllers
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  * Author: Michal Nazarewicz <mina86@mina86.com>
   6  *
   7  * Based on inode.c (GadgetFS) which was:
   8  * Copyright (C) 2003-2004 David Brownell
   9  * Copyright (C) 2003 Agilent Technologies
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  */
  16
  17
  18 /* #define DEBUG */
  19 /* #define VERBOSE_DEBUG */
  20
  21 #include <linux/blkdev.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/export.h>
  24 #include <linux/hid.h>
  25 #include <linux/module.h>
  26 #include <asm/unaligned.h>
  27
  28 #include <linux/usb/composite.h>
  29 #include <linux/usb/functionfs.h>
  30
  31 #include "u_fs.h"
  32 #include "configfs.h"
  33
  34 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  35
  36 /* Variable Length Array Macros **********************************************/
  37 #define vla_group(groupname) size_t groupname##__next = 0
  38 #define vla_group_size(groupname) groupname##__next
  39
  40 #define vla_item(groupname, type, name, n) \
  41         size_t groupname##_##name##__offset = ({                               \
  42                 size_t align_mask = __alignof__(type) - 1;                     \
  43                 size_t offset = (groupname##__next + align_mask) & ~align_mask;\
  44                 size_t size = (n) * sizeof(type);                              \
  45                 groupname##__next = offset + size;                             \
  46                 offset;                                                        \
  47         })
  48
  49 #define vla_item_with_sz(groupname, type, name, n) \
  50         size_t groupname##_##name##__sz = (n) * sizeof(type);                  \
  51         size_t groupname##_##name##__offset = ({                               \
  52                 size_t align_mask = __alignof__(type) - 1;                     \
  53                 size_t offset = (groupname##__next + align_mask) & ~align_mask;\
  54                 size_t size = groupname##_##name##__sz;                        \
  55                 groupname##__next = offset + size;                             \
  56                 offset;                                                        \
  57         })
  58
  59 #define vla_ptr(ptr, groupname, name) \
  60         ((void *) ((char *)ptr + groupname##_##name##__offset))
  61
  62 /* Reference counter handling */
  63 static void ffs_data_get(struct ffs_data *ffs);
  64 static void ffs_data_put(struct ffs_data *ffs);
  65 /* Creates new ffs_data object. */
  66 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
  67
  68 /* Opened counter handling. */
  69 static void ffs_data_opened(struct ffs_data *ffs);
  70 static void ffs_data_closed(struct ffs_data *ffs);
  71
  72 /* Called with ffs->mutex held; take over ownership of data. */
  73 static int __must_check
  74 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  75 static int __must_check
  76 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  77
  78
  79 /* The function structure ***************************************************/
  80
  81 struct ffs_ep;
  82
  83 struct ffs_function {
  84         struct usb_configuration        *conf;
  85         struct usb_gadget               *gadget;
  86         struct ffs_data                 *ffs;
  87
  88         struct ffs_ep                   *eps;
  89         u8                              eps_revmap[16];
  90         short                           *interfaces_nums;
  91
  92         struct usb_function             function;
  93 };
  94
  95
  96 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  97 {
  98         return container_of(f, struct ffs_function, function);
  99 }
 100
 101
 102 static inline enum ffs_setup_state
 103 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
 104 {
 105         return (enum ffs_setup_state)
 106                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
 107 }
 108
 109
 110 static void ffs_func_eps_disable(struct ffs_function *func);
 111 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
 112
 113 static int ffs_func_bind(struct usb_configuration *,
 114                          struct usb_function *);
 115 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 116 static void ffs_func_disable(struct usb_function *);
 117 static int ffs_func_setup(struct usb_function *,
 118                           const struct usb_ctrlrequest *);
 119 static void ffs_func_suspend(struct usb_function *);
 120 static void ffs_func_resume(struct usb_function *);
 121
 122
 123 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 124 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 125
 126
 127 /* The endpoints structures *************************************************/
 128
 129 struct ffs_ep {
 130         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 131         struct usb_request              *req;   /* P: epfile->mutex */
 132
 133         /* [0]: full speed, [1]: high speed */
 134         struct usb_endpoint_descriptor  *descs[2];
 135
 136         u8                              num;
 137
 138         int                             status; /* P: epfile->mutex */
 139 };
 140
 141 struct ffs_epfile {
 142         /* Protects ep->ep and ep->req. */
 143         struct mutex                    mutex;
 144         wait_queue_head_t               wait;
 145
 146         struct ffs_data                 *ffs;
 147         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 148
 149         struct dentry                   *dentry;
 150
 151         char                            name[5];
 152
 153         unsigned char                   in;     /* P: ffs->eps_lock */
 154         unsigned char                   isoc;   /* P: ffs->eps_lock */
 155
 156         unsigned char                   _pad;
 157 };
 158
 159 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 160 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 161
 162 static struct inode *__must_check
 163 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 164                    const struct file_operations *fops,
 165                    struct dentry **dentry_p);
 166
 167 /* Devices management *******************************************************/
 168
 169 DEFINE_MUTEX(ffs_lock);
 170 EXPORT_SYMBOL(ffs_lock);
 171
 172 static struct ffs_dev *_ffs_find_dev(const char *name);
 173 static struct ffs_dev *_ffs_alloc_dev(void);
 174 static int _ffs_name_dev(struct ffs_dev *dev, const char *name);
 175 static void _ffs_free_dev(struct ffs_dev *dev);
 176 static void *ffs_acquire_dev(const char *dev_name);
 177 static void ffs_release_dev(struct ffs_data *ffs_data);
 178 static int ffs_ready(struct ffs_data *ffs);
 179 static void ffs_closed(struct ffs_data *ffs);
 180
 181 /* Misc helper functions ****************************************************/
 182
 183 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 184         __attribute__((warn_unused_result, nonnull));
 185 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 186         __attribute__((warn_unused_result, nonnull));
 187
 188
 189 /* Control file aka ep0 *****************************************************/
 190
 191 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 192 {
 193         struct ffs_data *ffs = req->context;
 194
 195         complete_all(&ffs->ep0req_completion);
 196 }
 197
 198 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 199 {
 200         struct usb_request *req = ffs->ep0req;
 201         int ret;
 202
 203         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 204
 205         spin_unlock_irq(&ffs->ev.waitq.lock);
 206
 207         req->buf      = data;
 208         req->length   = len;
 209
 210         /*
 211          * UDC layer requires to provide a buffer even for ZLP, but should
 212          * not use it at all. Let's provide some poisoned pointer to catch
 213          * possible bug in the driver.
 214          */
 215         if (req->buf == NULL)
 216                 req->buf = (void *)0xDEADBABE;
 217
 218         reinit_completion(&ffs->ep0req_completion);
 219
 220         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 221         if (unlikely(ret < 0))
 222                 return ret;
 223
 224         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 225         if (unlikely(ret)) {
 226                 usb_ep_dequeue(ffs->gadget->ep0, req);
 227                 return -EINTR;
 228         }
 229
 230         ffs->setup_state = FFS_NO_SETUP;
 231         return ffs->ep0req_status;
 232 }
 233
 234 static int __ffs_ep0_stall(struct ffs_data *ffs)
 235 {
 236         if (ffs->ev.can_stall) {
 237                 pr_vdebug("ep0 stall\n");
 238                 usb_ep_set_halt(ffs->gadget->ep0);
 239                 ffs->setup_state = FFS_NO_SETUP;
 240                 return -EL2HLT;
 241         } else {
 242                 pr_debug("bogus ep0 stall!\n");
 243                 return -ESRCH;
 244         }
 245 }
 246
 247 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 248                              size_t len, loff_t *ptr)
 249 {
 250         struct ffs_data *ffs = file->private_data;
 251         ssize_t ret;
 252         char *data;
 253
 254         ENTER();
 255
 256         /* Fast check if setup was canceled */
 257         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 258                 return -EIDRM;
 259
 260         /* Acquire mutex */
 261         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 262         if (unlikely(ret < 0))
 263                 return ret;
 264
 265         /* Check state */
 266         switch (ffs->state) {
 267         case FFS_READ_DESCRIPTORS:
 268         case FFS_READ_STRINGS:
 269                 /* Copy data */
 270                 if (unlikely(len < 16)) {
 271                         ret = -EINVAL;
 272                         break;
 273                 }
 274
 275                 data = ffs_prepare_buffer(buf, len);
 276                 if (IS_ERR(data)) {
 277                         ret = PTR_ERR(data);
 278                         break;
 279                 }
 280
 281                 /* Handle data */
 282                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 283                         pr_info("read descriptors\n");
 284                         ret = __ffs_data_got_descs(ffs, data, len);
 285                         if (unlikely(ret < 0))
 286                                 break;
 287
 288                         ffs->state = FFS_READ_STRINGS;
 289                         ret = len;
 290                 } else {
 291                         pr_info("read strings\n");
 292                         ret = __ffs_data_got_strings(ffs, data, len);
 293                         if (unlikely(ret < 0))
 294                                 break;
 295
 296                         ret = ffs_epfiles_create(ffs);
 297                         if (unlikely(ret)) {
 298                                 ffs->state = FFS_CLOSING;
 299                                 break;
 300                         }
 301
 302                         ffs->state = FFS_ACTIVE;
 303                         mutex_unlock(&ffs->mutex);
 304
 305                         ret = ffs_ready(ffs);
 306                         if (unlikely(ret < 0)) {
 307                                 ffs->state = FFS_CLOSING;
 308                                 return ret;
 309                         }
 310
 311                         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
 312                         return len;
 313                 }
 314                 break;
 315
 316         case FFS_ACTIVE:
 317                 data = NULL;
 318                 /*
 319                  * We're called from user space, we can use _irq
 320                  * rather then _irqsave
 321                  */
 322                 spin_lock_irq(&ffs->ev.waitq.lock);
 323                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 324                 case FFS_SETUP_CANCELLED:
 325                         ret = -EIDRM;
 326                         goto done_spin;
 327
 328                 case FFS_NO_SETUP:
 329                         ret = -ESRCH;
 330                         goto done_spin;
 331
 332                 case FFS_SETUP_PENDING:
 333                         break;
 334                 }
 335
 336                 /* FFS_SETUP_PENDING */
 337                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 338                         spin_unlock_irq(&ffs->ev.waitq.lock);
 339                         ret = __ffs_ep0_stall(ffs);
 340                         break;
 341                 }
 342
 343                 /* FFS_SETUP_PENDING and not stall */
 344                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 345
 346                 spin_unlock_irq(&ffs->ev.waitq.lock);
 347
 348                 data = ffs_prepare_buffer(buf, len);
 349                 if (IS_ERR(data)) {
 350                         ret = PTR_ERR(data);
 351                         break;
 352                 }
 353
 354                 spin_lock_irq(&ffs->ev.waitq.lock);
 355
 356                 /*
 357                  * We are guaranteed to be still in FFS_ACTIVE state
 358                  * but the state of setup could have changed from
 359                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 360                  * to check for that.  If that happened we copied data
 361                  * from user space in vain but it's unlikely.
 362                  *
 363                  * For sure we are not in FFS_NO_SETUP since this is
 364                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 365                  * transition can be performed and it's protected by
 366                  * mutex.
 367                  */
 368                 if (ffs_setup_state_clear_cancelled(ffs) ==
 369                     FFS_SETUP_CANCELLED) {
 370                         ret = -EIDRM;
 371 done_spin:
 372                         spin_unlock_irq(&ffs->ev.waitq.lock);
 373                 } else {
 374                         /* unlocks spinlock */
 375                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 376                 }
 377                 kfree(data);
 378                 break;
 379
 380         default:
 381                 ret = -EBADFD;
 382                 break;
 383         }
 384
 385         mutex_unlock(&ffs->mutex);
 386         return ret;
 387 }
 388
 389 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 390                                      size_t n)
 391 {
 392         /*
 393          * We are holding ffs->ev.waitq.lock and ffs->mutex and we need
 394          * to release them.
 395          */
 396         struct usb_functionfs_event events[n];
 397         unsigned i = 0;
 398
 399         memset(events, 0, sizeof events);
 400
 401         do {
 402                 events[i].type = ffs->ev.types[i];
 403                 if (events[i].type == FUNCTIONFS_SETUP) {
 404                         events[i].u.setup = ffs->ev.setup;
 405                         ffs->setup_state = FFS_SETUP_PENDING;
 406                 }
 407         } while (++i < n);
 408
 409         if (n < ffs->ev.count) {
 410                 ffs->ev.count -= n;
 411                 memmove(ffs->ev.types, ffs->ev.types + n,
 412                         ffs->ev.count * sizeof *ffs->ev.types);
 413         } else {
 414                 ffs->ev.count = 0;
 415         }
 416
 417         spin_unlock_irq(&ffs->ev.waitq.lock);
 418         mutex_unlock(&ffs->mutex);
 419
 420         return unlikely(__copy_to_user(buf, events, sizeof events))
 421                 ? -EFAULT : sizeof events;
 422 }
 423
 424 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 425                             size_t len, loff_t *ptr)
 426 {
 427         struct ffs_data *ffs = file->private_data;
 428         char *data = NULL;
 429         size_t n;
 430         int ret;
 431
 432         ENTER();
 433
 434         /* Fast check if setup was canceled */
 435         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 436                 return -EIDRM;
 437
 438         /* Acquire mutex */
 439         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 440         if (unlikely(ret < 0))
 441                 return ret;
 442
 443         /* Check state */
 444         if (ffs->state != FFS_ACTIVE) {
 445                 ret = -EBADFD;
 446                 goto done_mutex;
 447         }
 448
 449         /*
 450          * We're called from user space, we can use _irq rather then
 451          * _irqsave
 452          */
 453         spin_lock_irq(&ffs->ev.waitq.lock);
 454
 455         switch (ffs_setup_state_clear_cancelled(ffs)) {
 456         case FFS_SETUP_CANCELLED:
 457                 ret = -EIDRM;
 458                 break;
 459
 460         case FFS_NO_SETUP:
 461                 n = len / sizeof(struct usb_functionfs_event);
 462                 if (unlikely(!n)) {
 463                         ret = -EINVAL;
 464                         break;
 465                 }
 466
 467                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 468                         ret = -EAGAIN;
 469                         break;
 470                 }
 471
 472                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 473                                                         ffs->ev.count)) {
 474                         ret = -EINTR;
 475                         break;
 476                 }
 477
 478                 return __ffs_ep0_read_events(ffs, buf,
 479                                              min(n, (size_t)ffs->ev.count));
 480
 481         case FFS_SETUP_PENDING:
 482                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 483                         spin_unlock_irq(&ffs->ev.waitq.lock);
 484                         ret = __ffs_ep0_stall(ffs);
 485                         goto done_mutex;
 486                 }
 487
 488                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 489
 490                 spin_unlock_irq(&ffs->ev.waitq.lock);
 491
 492                 if (likely(len)) {
 493                         data = kmalloc(len, GFP_KERNEL);
 494                         if (unlikely(!data)) {
 495                                 ret = -ENOMEM;
 496                                 goto done_mutex;
 497                         }
 498                 }
 499
 500                 spin_lock_irq(&ffs->ev.waitq.lock);
 501
 502                 /* See ffs_ep0_write() */
 503                 if (ffs_setup_state_clear_cancelled(ffs) ==
 504                     FFS_SETUP_CANCELLED) {
 505                         ret = -EIDRM;
 506                         break;
 507                 }
 508
 509                 /* unlocks spinlock */
 510                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 511                 if (likely(ret > 0) && unlikely(__copy_to_user(buf, data, len)))
 512                         ret = -EFAULT;
 513                 goto done_mutex;
 514
 515         default:
 516                 ret = -EBADFD;
 517                 break;
 518         }
 519
 520         spin_unlock_irq(&ffs->ev.waitq.lock);
 521 done_mutex:
 522         mutex_unlock(&ffs->mutex);
 523         kfree(data);
 524         return ret;
 525 }
 526
 527 static int ffs_ep0_open(struct inode *inode, struct file *file)
 528 {
 529         struct ffs_data *ffs = inode->i_private;
 530
 531         ENTER();
 532
 533         if (unlikely(ffs->state == FFS_CLOSING))
 534                 return -EBUSY;
 535
 536         file->private_data = ffs;
 537         ffs_data_opened(ffs);
 538
 539         return 0;
 540 }
 541
 542 static int ffs_ep0_release(struct inode *inode, struct file *file)
 543 {
 544         struct ffs_data *ffs = file->private_data;
 545
 546         ENTER();
 547
 548         ffs_data_closed(ffs);
 549
 550         return 0;
 551 }
 552
 553 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 554 {
 555         struct ffs_data *ffs = file->private_data;
 556         struct usb_gadget *gadget = ffs->gadget;
 557         long ret;
 558
 559         ENTER();
 560
 561         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 562                 struct ffs_function *func = ffs->func;
 563                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 564         } else if (gadget && gadget->ops->ioctl) {
 565                 ret = gadget->ops->ioctl(gadget, code, value);
 566         } else {
 567                 ret = -ENOTTY;
 568         }
 569
 570         return ret;
 571 }
 572
 573 static const struct file_operations ffs_ep0_operations = {
 574         .llseek =       no_llseek,
 575
 576         .open =         ffs_ep0_open,
 577         .write =        ffs_ep0_write,
 578         .read =         ffs_ep0_read,
 579         .release =      ffs_ep0_release,
 580         .unlocked_ioctl =       ffs_ep0_ioctl,
 581 };
 582
 583
 584 /* "Normal" endpoints operations ********************************************/
 585
 586 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 587 {
 588         ENTER();
 589         if (likely(req->context)) {
 590                 struct ffs_ep *ep = _ep->driver_data;
 591                 ep->status = req->status ? req->status : req->actual;
 592                 complete(req->context);
 593         }
 594 }
 595
 596 static ssize_t ffs_epfile_io(struct file *file,
 597                              char __user *buf, size_t len, int read)
 598 {
 599         struct ffs_epfile *epfile = file->private_data;
 600         struct usb_gadget *gadget = epfile->ffs->gadget;
 601         struct ffs_ep *ep;
 602         char *data = NULL;
 603         ssize_t ret, data_len;
 604         int halt;
 605
 606         /* Are we still active? */
 607         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
 608                 ret = -ENODEV;
 609                 goto error;
 610         }
 611
 612         /* Wait for endpoint to be enabled */
 613         ep = epfile->ep;
 614         if (!ep) {
 615                 if (file->f_flags & O_NONBLOCK) {
 616                         ret = -EAGAIN;
 617                         goto error;
 618                 }
 619
 620                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
 621                 if (ret) {
 622                         ret = -EINTR;
 623                         goto error;
 624                 }
 625         }
 626
 627         /* Do we halt? */
 628         halt = !read == !epfile->in;
 629         if (halt && epfile->isoc) {
 630                 ret = -EINVAL;
 631                 goto error;
 632         }
 633
 634         /* Allocate & copy */
 635         if (!halt) {
 636                 /*
 637                  * Controller may require buffer size to be aligned to
 638                  * maxpacketsize of an out endpoint.
 639                  */
 640                 data_len = read ? usb_ep_align_maybe(gadget, ep->ep, len) : len;
 641
 642                 data = kmalloc(data_len, GFP_KERNEL);
 643                 if (unlikely(!data))
 644                         return -ENOMEM;
 645
 646                 if (!read && unlikely(copy_from_user(data, buf, len))) {
 647                         ret = -EFAULT;
 648                         goto error;
 649                 }
 650         }
 651
 652         /* We will be using request */
 653         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 654         if (unlikely(ret))
 655                 goto error;
 656
 657         spin_lock_irq(&epfile->ffs->eps_lock);
 658
 659         if (epfile->ep != ep) {
 660                 /* In the meantime, endpoint got disabled or changed. */
 661                 ret = -ESHUTDOWN;
 662                 spin_unlock_irq(&epfile->ffs->eps_lock);
 663         } else if (halt) {
 664                 /* Halt */
 665                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 666                         usb_ep_set_halt(ep->ep);
 667                 spin_unlock_irq(&epfile->ffs->eps_lock);
 668                 ret = -EBADMSG;
 669         } else {
 670                 /* Fire the request */
 671                 DECLARE_COMPLETION_ONSTACK(done);
 672
 673                 struct usb_request *req = ep->req;
 674                 req->context  = &done;
 675                 req->complete = ffs_epfile_io_complete;
 676                 req->buf      = data;
 677                 req->length   = data_len;
 678
 679                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 680
 681                 spin_unlock_irq(&epfile->ffs->eps_lock);
 682
 683                 if (unlikely(ret < 0)) {
 684                         /* nop */
 685                 } else if (unlikely(wait_for_completion_interruptible(&done))) {
 686                         ret = -EINTR;
 687                         usb_ep_dequeue(ep->ep, req);
 688                 } else {
 689                         /*
 690                          * XXX We may end up silently droping data here.
 691                          * Since data_len (i.e. req->length) may be bigger
 692                          * than len (after being rounded up to maxpacketsize),
 693                          * we may end up with more data then user space has
 694                          * space for.
 695                          */
 696                         ret = ep->status;
 697                         if (read && ret > 0 &&
 698                             unlikely(copy_to_user(buf, data,
 699                                                   min_t(size_t, ret, len))))
 700                                 ret = -EFAULT;
 701                 }
 702         }
 703
 704         mutex_unlock(&epfile->mutex);
 705 error:
 706         kfree(data);
 707         return ret;
 708 }
 709
 710 static ssize_t
 711 ffs_epfile_write(struct file *file, const char __user *buf, size_t len,
 712                  loff_t *ptr)
 713 {
 714         ENTER();
 715
 716         return ffs_epfile_io(file, (char __user *)buf, len, 0);
 717 }
 718
 719 static ssize_t
 720 ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr)
 721 {
 722         ENTER();
 723
 724         return ffs_epfile_io(file, buf, len, 1);
 725 }
 726
 727 static int
 728 ffs_epfile_open(struct inode *inode, struct file *file)
 729 {
 730         struct ffs_epfile *epfile = inode->i_private;
 731
 732         ENTER();
 733
 734         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 735                 return -ENODEV;
 736
 737         file->private_data = epfile;
 738         ffs_data_opened(epfile->ffs);
 739
 740         return 0;
 741 }
 742
 743 static int
 744 ffs_epfile_release(struct inode *inode, struct file *file)
 745 {
 746         struct ffs_epfile *epfile = inode->i_private;
 747
 748         ENTER();
 749
 750         ffs_data_closed(epfile->ffs);
 751
 752         return 0;
 753 }
 754
 755 static long ffs_epfile_ioctl(struct file *file, unsigned code,
 756                              unsigned long value)
 757 {
 758         struct ffs_epfile *epfile = file->private_data;
 759         int ret;
 760
 761         ENTER();
 762
 763         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 764                 return -ENODEV;
 765
 766         spin_lock_irq(&epfile->ffs->eps_lock);
 767         if (likely(epfile->ep)) {
 768                 switch (code) {
 769                 case FUNCTIONFS_FIFO_STATUS:
 770                         ret = usb_ep_fifo_status(epfile->ep->ep);
 771                         break;
 772                 case FUNCTIONFS_FIFO_FLUSH:
 773                         usb_ep_fifo_flush(epfile->ep->ep);
 774                         ret = 0;
 775                         break;
 776                 case FUNCTIONFS_CLEAR_HALT:
 777                         ret = usb_ep_clear_halt(epfile->ep->ep);
 778                         break;
 779                 case FUNCTIONFS_ENDPOINT_REVMAP:
 780                         ret = epfile->ep->num;
 781                         break;
 782                 default:
 783                         ret = -ENOTTY;
 784                 }
 785         } else {
 786                 ret = -ENODEV;
 787         }
 788         spin_unlock_irq(&epfile->ffs->eps_lock);
 789
 790         return ret;
 791 }
 792
 793 static const struct file_operations ffs_epfile_operations = {
 794         .llseek =       no_llseek,
 795
 796         .open =         ffs_epfile_open,
 797         .write =        ffs_epfile_write,
 798         .read =         ffs_epfile_read,
 799         .release =      ffs_epfile_release,
 800         .unlocked_ioctl =       ffs_epfile_ioctl,
 801 };
 802
 803
 804 /* File system and super block operations ***********************************/
 805
 806 /*
 807  * Mounting the file system creates a controller file, used first for
 808  * function configuration then later for event monitoring.
 809  */
 810
 811 static struct inode *__must_check
 812 ffs_sb_make_inode(struct super_block *sb, void *data,
 813                   const struct file_operations *fops,
 814                   const struct inode_operations *iops,
 815                   struct ffs_file_perms *perms)
 816 {
 817         struct inode *inode;
 818
 819         ENTER();
 820
 821         inode = new_inode(sb);
 822
 823         if (likely(inode)) {
 824                 struct timespec current_time = CURRENT_TIME;
 825
 826                 inode->i_ino     = get_next_ino();
 827                 inode->i_mode    = perms->mode;
 828                 inode->i_uid     = perms->uid;
 829                 inode->i_gid     = perms->gid;
 830                 inode->i_atime   = current_time;
 831                 inode->i_mtime   = current_time;
 832                 inode->i_ctime   = current_time;
 833                 inode->i_private = data;
 834                 if (fops)
 835                         inode->i_fop = fops;
 836                 if (iops)
 837                         inode->i_op  = iops;
 838         }
 839
 840         return inode;
 841 }
 842
 843 /* Create "regular" file */
 844 static struct inode *ffs_sb_create_file(struct super_block *sb,
 845                                         const char *name, void *data,
 846                                         const struct file_operations *fops,
 847                                         struct dentry **dentry_p)
 848 {
 849         struct ffs_data *ffs = sb->s_fs_info;
 850         struct dentry   *dentry;
 851         struct inode    *inode;
 852
 853         ENTER();
 854
 855         dentry = d_alloc_name(sb->s_root, name);
 856         if (unlikely(!dentry))
 857                 return NULL;
 858
 859         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
 860         if (unlikely(!inode)) {
 861                 dput(dentry);
 862                 return NULL;
 863         }
 864
 865         d_add(dentry, inode);
 866         if (dentry_p)
 867                 *dentry_p = dentry;
 868
 869         return inode;
 870 }
 871
 872 /* Super block */
 873 static const struct super_operations ffs_sb_operations = {
 874         .statfs =       simple_statfs,
 875         .drop_inode =   generic_delete_inode,
 876 };
 877
 878 struct ffs_sb_fill_data {
 879         struct ffs_file_perms perms;
 880         umode_t root_mode;
 881         const char *dev_name;
 882         struct ffs_data *ffs_data;
 883 };
 884
 885 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
 886 {
 887         struct ffs_sb_fill_data *data = _data;
 888         struct inode    *inode;
 889         struct ffs_data *ffs = data->ffs_data;
 890
 891         ENTER();
 892
 893         ffs->sb              = sb;
 894         data->ffs_data       = NULL;
 895         sb->s_fs_info        = ffs;
 896         sb->s_blocksize      = PAGE_CACHE_SIZE;
 897         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 898         sb->s_magic          = FUNCTIONFS_MAGIC;
 899         sb->s_op             = &ffs_sb_operations;
 900         sb->s_time_gran      = 1;
 901
 902         /* Root inode */
 903         data->perms.mode = data->root_mode;
 904         inode = ffs_sb_make_inode(sb, NULL,
 905                                   &simple_dir_operations,
 906                                   &simple_dir_inode_operations,
 907                                   &data->perms);
 908         sb->s_root = d_make_root(inode);
 909         if (unlikely(!sb->s_root))
 910                 return -ENOMEM;
 911
 912         /* EP0 file */
 913         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
 914                                          &ffs_ep0_operations, NULL)))
 915                 return -ENOMEM;
 916
 917         return 0;
 918 }
 919
 920 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
 921 {
 922         ENTER();
 923
 924         if (!opts || !*opts)
 925                 return 0;
 926
 927         for (;;) {
 928                 unsigned long value;
 929                 char *eq, *comma;
 930
 931                 /* Option limit */
 932                 comma = strchr(opts, ',');
 933                 if (comma)
 934                         *comma = 0;
 935
 936                 /* Value limit */
 937                 eq = strchr(opts, '=');
 938                 if (unlikely(!eq)) {
 939                         pr_err("'=' missing in %s\n", opts);
 940                         return -EINVAL;
 941                 }
 942                 *eq = 0;
 943
 944                 /* Parse value */
 945                 if (kstrtoul(eq + 1, 0, &value)) {
 946                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
 947                         return -EINVAL;
 948                 }
 949
 950                 /* Interpret option */
 951                 switch (eq - opts) {
 952                 case 5:
 953                         if (!memcmp(opts, "rmode", 5))
 954                                 data->root_mode  = (value & 0555) | S_IFDIR;
 955                         else if (!memcmp(opts, "fmode", 5))
 956                                 data->perms.mode = (value & 0666) | S_IFREG;
 957                         else
 958                                 goto invalid;
 959                         break;
 960
 961                 case 4:
 962                         if (!memcmp(opts, "mode", 4)) {
 963                                 data->root_mode  = (value & 0555) | S_IFDIR;
 964                                 data->perms.mode = (value & 0666) | S_IFREG;
 965                         } else {
 966                                 goto invalid;
 967                         }
 968                         break;
 969
 970                 case 3:
 971                         if (!memcmp(opts, "uid", 3)) {
 972                                 data->perms.uid = make_kuid(current_user_ns(), value);
 973                                 if (!uid_valid(data->perms.uid)) {
 974                                         pr_err("%s: unmapped value: %lu\n", opts, value);
 975                                         return -EINVAL;
 976                                 }
 977                         } else if (!memcmp(opts, "gid", 3)) {
 978                                 data->perms.gid = make_kgid(current_user_ns(), value);
 979                                 if (!gid_valid(data->perms.gid)) {
 980                                         pr_err("%s: unmapped value: %lu\n", opts, value);
 981                                         return -EINVAL;
 982                                 }
 983                         } else {
 984                                 goto invalid;
 985                         }
 986                         break;
 987
 988                 default:
 989 invalid:
 990                         pr_err("%s: invalid option\n", opts);
 991                         return -EINVAL;
 992                 }
 993
 994                 /* Next iteration */
 995                 if (!comma)
 996                         break;
 997                 opts = comma + 1;
 998         }
 999
1000         return 0;
1001 }
1002
1003 /* "mount -t functionfs dev_name /dev/function" ends up here */
1004
1005 static struct dentry *
1006 ffs_fs_mount(struct file_system_type *t, int flags,
1007               const char *dev_name, void *opts)
1008 {
1009         struct ffs_sb_fill_data data = {
1010                 .perms = {
1011                         .mode = S_IFREG | 0600,
1012                         .uid = GLOBAL_ROOT_UID,
1013                         .gid = GLOBAL_ROOT_GID,
1014                 },
1015                 .root_mode = S_IFDIR | 0500,
1016         };
1017         struct dentry *rv;
1018         int ret;
1019         void *ffs_dev;
1020         struct ffs_data *ffs;
1021
1022         ENTER();
1023
1024         ret = ffs_fs_parse_opts(&data, opts);
1025         if (unlikely(ret < 0))
1026                 return ERR_PTR(ret);
1027
1028         ffs = ffs_data_new();
1029         if (unlikely(!ffs))
1030                 return ERR_PTR(-ENOMEM);
1031         ffs->file_perms = data.perms;
1032
1033         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1034         if (unlikely(!ffs->dev_name)) {
1035                 ffs_data_put(ffs);
1036                 return ERR_PTR(-ENOMEM);
1037         }
1038
1039         ffs_dev = ffs_acquire_dev(dev_name);
1040         if (IS_ERR(ffs_dev)) {
1041                 ffs_data_put(ffs);
1042                 return ERR_CAST(ffs_dev);
1043         }
1044         ffs->private_data = ffs_dev;
1045         data.ffs_data = ffs;
1046
1047         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1048         if (IS_ERR(rv) && data.ffs_data) {
1049                 ffs_release_dev(data.ffs_data);
1050                 ffs_data_put(data.ffs_data);
1051         }
1052         return rv;
1053 }
1054
1055 static void
1056 ffs_fs_kill_sb(struct super_block *sb)
1057 {
1058         ENTER();
1059
1060         kill_litter_super(sb);
1061         if (sb->s_fs_info) {
1062                 ffs_release_dev(sb->s_fs_info);
1063                 ffs_data_put(sb->s_fs_info);
1064         }
1065 }
1066
1067 static struct file_system_type ffs_fs_type = {
1068         .owner          = THIS_MODULE,
1069         .name           = "functionfs",
1070         .mount          = ffs_fs_mount,
1071         .kill_sb        = ffs_fs_kill_sb,
1072 };
1073 MODULE_ALIAS_FS("functionfs");
1074
1075
1076 /* Driver's main init/cleanup functions *************************************/
1077
1078 static int functionfs_init(void)
1079 {
1080         int ret;
1081
1082         ENTER();
1083
1084         ret = register_filesystem(&ffs_fs_type);
1085         if (likely(!ret))
1086                 pr_info("file system registered\n");
1087         else
1088                 pr_err("failed registering file system (%d)\n", ret);
1089
1090         return ret;
1091 }
1092
1093 static void functionfs_cleanup(void)
1094 {
1095         ENTER();
1096
1097         pr_info("unloading\n");
1098         unregister_filesystem(&ffs_fs_type);
1099 }
1100
1101
1102 /* ffs_data and ffs_function construction and destruction code **************/
1103
1104 static void ffs_data_clear(struct ffs_data *ffs);
1105 static void ffs_data_reset(struct ffs_data *ffs);
1106
1107 static void ffs_data_get(struct ffs_data *ffs)
1108 {
1109         ENTER();
1110
1111         atomic_inc(&ffs->ref);
1112 }
1113
1114 static void ffs_data_opened(struct ffs_data *ffs)
1115 {
1116         ENTER();
1117
1118         atomic_inc(&ffs->ref);
1119         atomic_inc(&ffs->opened);
1120 }
1121
1122 static void ffs_data_put(struct ffs_data *ffs)
1123 {
1124         ENTER();
1125
1126         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1127                 pr_info("%s(): freeing\n", __func__);
1128                 ffs_data_clear(ffs);
1129                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1130                        waitqueue_active(&ffs->ep0req_completion.wait));
1131                 kfree(ffs->dev_name);
1132                 kfree(ffs);
1133         }
1134 }
1135
1136 static void ffs_data_closed(struct ffs_data *ffs)
1137 {
1138         ENTER();
1139
1140         if (atomic_dec_and_test(&ffs->opened)) {
1141                 ffs->state = FFS_CLOSING;
1142                 ffs_data_reset(ffs);
1143         }
1144
1145         ffs_data_put(ffs);
1146 }
1147
1148 static struct ffs_data *ffs_data_new(void)
1149 {
1150         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1151         if (unlikely(!ffs))
1152                 return NULL;
1153
1154         ENTER();
1155
1156         atomic_set(&ffs->ref, 1);
1157         atomic_set(&ffs->opened, 0);
1158         ffs->state = FFS_READ_DESCRIPTORS;
1159         mutex_init(&ffs->mutex);
1160         spin_lock_init(&ffs->eps_lock);
1161         init_waitqueue_head(&ffs->ev.waitq);
1162         init_completion(&ffs->ep0req_completion);
1163
1164         /* XXX REVISIT need to update it in some places, or do we? */
1165         ffs->ev.can_stall = 1;
1166
1167         return ffs;
1168 }
1169
1170 static void ffs_data_clear(struct ffs_data *ffs)
1171 {
1172         ENTER();
1173
1174         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags))
1175                 ffs_closed(ffs);
1176
1177         BUG_ON(ffs->gadget);
1178
1179         if (ffs->epfiles)
1180                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1181
1182         kfree(ffs->raw_descs);
1183         kfree(ffs->raw_strings);
1184         kfree(ffs->stringtabs);
1185 }
1186
1187 static void ffs_data_reset(struct ffs_data *ffs)
1188 {
1189         ENTER();
1190
1191         ffs_data_clear(ffs);
1192
1193         ffs->epfiles = NULL;
1194         ffs->raw_descs = NULL;
1195         ffs->raw_strings = NULL;
1196         ffs->stringtabs = NULL;
1197
1198         ffs->raw_descs_length = 0;
1199         ffs->raw_fs_descs_length = 0;
1200         ffs->fs_descs_count = 0;
1201         ffs->hs_descs_count = 0;
1202
1203         ffs->strings_count = 0;
1204         ffs->interfaces_count = 0;
1205         ffs->eps_count = 0;
1206
1207         ffs->ev.count = 0;
1208
1209         ffs->state = FFS_READ_DESCRIPTORS;
1210         ffs->setup_state = FFS_NO_SETUP;
1211         ffs->flags = 0;
1212 }
1213
1214
1215 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1216 {
1217         struct usb_gadget_strings **lang;
1218         int first_id;
1219
1220         ENTER();
1221
1222         if (WARN_ON(ffs->state != FFS_ACTIVE
1223                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1224                 return -EBADFD;
1225
1226         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1227         if (unlikely(first_id < 0))
1228                 return first_id;
1229
1230         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1231         if (unlikely(!ffs->ep0req))
1232                 return -ENOMEM;
1233         ffs->ep0req->complete = ffs_ep0_complete;
1234         ffs->ep0req->context = ffs;
1235
1236         lang = ffs->stringtabs;
1237         for (lang = ffs->stringtabs; *lang; ++lang) {
1238                 struct usb_string *str = (*lang)->strings;
1239                 int id = first_id;
1240                 for (; str->s; ++id, ++str)
1241                         str->id = id;
1242         }
1243
1244         ffs->gadget = cdev->gadget;
1245         ffs_data_get(ffs);
1246         return 0;
1247 }
1248
1249 static void functionfs_unbind(struct ffs_data *ffs)
1250 {
1251         ENTER();
1252
1253         if (!WARN_ON(!ffs->gadget)) {
1254                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1255                 ffs->ep0req = NULL;
1256                 ffs->gadget = NULL;
1257                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1258                 ffs_data_put(ffs);
1259         }
1260 }
1261
1262 static int ffs_epfiles_create(struct ffs_data *ffs)
1263 {
1264         struct ffs_epfile *epfile, *epfiles;
1265         unsigned i, count;
1266
1267         ENTER();
1268
1269         count = ffs->eps_count;
1270         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1271         if (!epfiles)
1272                 return -ENOMEM;
1273
1274         epfile = epfiles;
1275         for (i = 1; i <= count; ++i, ++epfile) {
1276                 epfile->ffs = ffs;
1277                 mutex_init(&epfile->mutex);
1278                 init_waitqueue_head(&epfile->wait);
1279                 sprintf(epfiles->name, "ep%u",  i);
1280                 if (!unlikely(ffs_sb_create_file(ffs->sb, epfiles->name, epfile,
1281                                                  &ffs_epfile_operations,
1282                                                  &epfile->dentry))) {
1283                         ffs_epfiles_destroy(epfiles, i - 1);
1284                         return -ENOMEM;
1285                 }
1286         }
1287
1288         ffs->epfiles = epfiles;
1289         return 0;
1290 }
1291
1292 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1293 {
1294         struct ffs_epfile *epfile = epfiles;
1295
1296         ENTER();
1297
1298         for (; count; --count, ++epfile) {
1299                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1300                        waitqueue_active(&epfile->wait));
1301                 if (epfile->dentry) {
1302                         d_delete(epfile->dentry);
1303                         dput(epfile->dentry);
1304                         epfile->dentry = NULL;
1305                 }
1306         }
1307
1308         kfree(epfiles);
1309 }
1310
1311
1312 static void ffs_func_eps_disable(struct ffs_function *func)
1313 {
1314         struct ffs_ep *ep         = func->eps;
1315         struct ffs_epfile *epfile = func->ffs->epfiles;
1316         unsigned count            = func->ffs->eps_count;
1317         unsigned long flags;
1318
1319         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1320         do {
1321                 /* pending requests get nuked */
1322                 if (likely(ep->ep))
1323                         usb_ep_disable(ep->ep);
1324                 epfile->ep = NULL;
1325
1326                 ++ep;
1327                 ++epfile;
1328         } while (--count);
1329         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1330 }
1331
1332 static int ffs_func_eps_enable(struct ffs_function *func)
1333 {
1334         struct ffs_data *ffs      = func->ffs;
1335         struct ffs_ep *ep         = func->eps;
1336         struct ffs_epfile *epfile = ffs->epfiles;
1337         unsigned count            = ffs->eps_count;
1338         unsigned long flags;
1339         int ret = 0;
1340
1341         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1342         do {
1343                 struct usb_endpoint_descriptor *ds;
1344                 ds = ep->descs[ep->descs[1] ? 1 : 0];
1345
1346                 ep->ep->driver_data = ep;
1347                 ep->ep->desc = ds;
1348                 ret = usb_ep_enable(ep->ep);
1349                 if (likely(!ret)) {
1350                         epfile->ep = ep;
1351                         epfile->in = usb_endpoint_dir_in(ds);
1352                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1353                 } else {
1354                         break;
1355                 }
1356
1357                 wake_up(&epfile->wait);
1358
1359                 ++ep;
1360                 ++epfile;
1361         } while (--count);
1362         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1363
1364         return ret;
1365 }
1366
1367
1368 /* Parsing and building descriptors and strings *****************************/
1369
1370 /*
1371  * This validates if data pointed by data is a valid USB descriptor as
1372  * well as record how many interfaces, endpoints and strings are
1373  * required by given configuration.  Returns address after the
1374  * descriptor or NULL if data is invalid.
1375  */
1376
1377 enum ffs_entity_type {
1378         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1379 };
1380
1381 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1382                                    u8 *valuep,
1383                                    struct usb_descriptor_header *desc,
1384                                    void *priv);
1385
1386 static int __must_check ffs_do_desc(char *data, unsigned len,
1387                                     ffs_entity_callback entity, void *priv)
1388 {
1389         struct usb_descriptor_header *_ds = (void *)data;
1390         u8 length;
1391         int ret;
1392
1393         ENTER();
1394
1395         /* At least two bytes are required: length and type */
1396         if (len < 2) {
1397                 pr_vdebug("descriptor too short\n");
1398                 return -EINVAL;
1399         }
1400
1401         /* If we have at least as many bytes as the descriptor takes? */
1402         length = _ds->bLength;
1403         if (len < length) {
1404                 pr_vdebug("descriptor longer then available data\n");
1405                 return -EINVAL;
1406         }
1407
1408 #define __entity_check_INTERFACE(val)  1
1409 #define __entity_check_STRING(val)     (val)
1410 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1411 #define __entity(type, val) do {                                        \
1412                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1413                 if (unlikely(!__entity_check_ ##type(val))) {           \
1414                         pr_vdebug("invalid entity's value\n");          \
1415                         return -EINVAL;                                 \
1416                 }                                                       \
1417                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1418                 if (unlikely(ret < 0)) {                                \
1419                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1420                                  (val), ret);                           \
1421                         return ret;                                     \
1422                 }                                                       \
1423         } while (0)
1424
1425         /* Parse descriptor depending on type. */
1426         switch (_ds->bDescriptorType) {
1427         case USB_DT_DEVICE:
1428         case USB_DT_CONFIG:
1429         case USB_DT_STRING:
1430         case USB_DT_DEVICE_QUALIFIER:
1431                 /* function can't have any of those */
1432                 pr_vdebug("descriptor reserved for gadget: %d\n",
1433                       _ds->bDescriptorType);
1434                 return -EINVAL;
1435
1436         case USB_DT_INTERFACE: {
1437                 struct usb_interface_descriptor *ds = (void *)_ds;
1438                 pr_vdebug("interface descriptor\n");
1439                 if (length != sizeof *ds)
1440                         goto inv_length;
1441
1442                 __entity(INTERFACE, ds->bInterfaceNumber);
1443                 if (ds->iInterface)
1444                         __entity(STRING, ds->iInterface);
1445         }
1446                 break;
1447
1448         case USB_DT_ENDPOINT: {
1449                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1450                 pr_vdebug("endpoint descriptor\n");
1451                 if (length != USB_DT_ENDPOINT_SIZE &&
1452                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1453                         goto inv_length;
1454                 __entity(ENDPOINT, ds->bEndpointAddress);
1455         }
1456                 break;
1457
1458         case HID_DT_HID:
1459                 pr_vdebug("hid descriptor\n");
1460                 if (length != sizeof(struct hid_descriptor))
1461                         goto inv_length;
1462                 break;
1463
1464         case USB_DT_OTG:
1465                 if (length != sizeof(struct usb_otg_descriptor))
1466                         goto inv_length;
1467                 break;
1468
1469         case USB_DT_INTERFACE_ASSOCIATION: {
1470                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1471                 pr_vdebug("interface association descriptor\n");
1472                 if (length != sizeof *ds)
1473                         goto inv_length;
1474                 if (ds->iFunction)
1475                         __entity(STRING, ds->iFunction);
1476         }
1477                 break;
1478
1479         case USB_DT_OTHER_SPEED_CONFIG:
1480         case USB_DT_INTERFACE_POWER:
1481         case USB_DT_DEBUG:
1482         case USB_DT_SECURITY:
1483         case USB_DT_CS_RADIO_CONTROL:
1484                 /* TODO */
1485                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1486                 return -EINVAL;
1487
1488         default:
1489                 /* We should never be here */
1490                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1491                 return -EINVAL;
1492
1493 inv_length:
1494                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1495                           _ds->bLength, _ds->bDescriptorType);
1496                 return -EINVAL;
1497         }
1498
1499 #undef __entity
1500 #undef __entity_check_DESCRIPTOR
1501 #undef __entity_check_INTERFACE
1502 #undef __entity_check_STRING
1503 #undef __entity_check_ENDPOINT
1504
1505         return length;
1506 }
1507
1508 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1509                                      ffs_entity_callback entity, void *priv)
1510 {
1511         const unsigned _len = len;
1512         unsigned long num = 0;
1513
1514         ENTER();
1515
1516         for (;;) {
1517                 int ret;
1518
1519                 if (num == count)
1520                         data = NULL;
1521
1522                 /* Record "descriptor" entity */
1523                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1524                 if (unlikely(ret < 0)) {
1525                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1526                                  num, ret);
1527                         return ret;
1528                 }
1529
1530                 if (!data)
1531                         return _len - len;
1532
1533                 ret = ffs_do_desc(data, len, entity, priv);
1534                 if (unlikely(ret < 0)) {
1535                         pr_debug("%s returns %d\n", __func__, ret);
1536                         return ret;
1537                 }
1538
1539                 len -= ret;
1540                 data += ret;
1541                 ++num;
1542         }
1543 }
1544
1545 static int __ffs_data_do_entity(enum ffs_entity_type type,
1546                                 u8 *valuep, struct usb_descriptor_header *desc,
1547                                 void *priv)
1548 {
1549         struct ffs_data *ffs = priv;
1550
1551         ENTER();
1552
1553         switch (type) {
1554         case FFS_DESCRIPTOR:
1555                 break;
1556
1557         case FFS_INTERFACE:
1558                 /*
1559                  * Interfaces are indexed from zero so if we
1560                  * encountered interface "n" then there are at least
1561                  * "n+1" interfaces.
1562                  */
1563                 if (*valuep >= ffs->interfaces_count)
1564                         ffs->interfaces_count = *valuep + 1;
1565                 break;
1566
1567         case FFS_STRING:
1568                 /*
1569                  * Strings are indexed from 1 (0 is magic ;) reserved
1570                  * for languages list or some such)
1571                  */
1572                 if (*valuep > ffs->strings_count)
1573                         ffs->strings_count = *valuep;
1574                 break;
1575
1576         case FFS_ENDPOINT:
1577                 /* Endpoints are indexed from 1 as well. */
1578                 if ((*valuep & USB_ENDPOINT_NUMBER_MASK) > ffs->eps_count)
1579                         ffs->eps_count = (*valuep & USB_ENDPOINT_NUMBER_MASK);
1580                 break;
1581         }
1582
1583         return 0;
1584 }
1585
1586 static int __ffs_data_got_descs(struct ffs_data *ffs,
1587                                 char *const _data, size_t len)
1588 {
1589         unsigned fs_count, hs_count;
1590         int fs_len, ret = -EINVAL;
1591         char *data = _data;
1592
1593         ENTER();
1594
1595         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_DESCRIPTORS_MAGIC ||
1596                      get_unaligned_le32(data + 4) != len))
1597                 goto error;
1598         fs_count = get_unaligned_le32(data +  8);
1599         hs_count = get_unaligned_le32(data + 12);
1600
1601         if (!fs_count && !hs_count)
1602                 goto einval;
1603
1604         data += 16;
1605         len  -= 16;
1606
1607         if (likely(fs_count)) {
1608                 fs_len = ffs_do_descs(fs_count, data, len,
1609                                       __ffs_data_do_entity, ffs);
1610                 if (unlikely(fs_len < 0)) {
1611                         ret = fs_len;
1612                         goto error;
1613                 }
1614
1615                 data += fs_len;
1616                 len  -= fs_len;
1617         } else {
1618                 fs_len = 0;
1619         }
1620
1621         if (likely(hs_count)) {
1622                 ret = ffs_do_descs(hs_count, data, len,
1623                                    __ffs_data_do_entity, ffs);
1624                 if (unlikely(ret < 0))
1625                         goto error;
1626         } else {
1627                 ret = 0;
1628         }
1629
1630         if (unlikely(len != ret))
1631                 goto einval;
1632
1633         ffs->raw_fs_descs_length = fs_len;
1634         ffs->raw_descs_length    = fs_len + ret;
1635         ffs->raw_descs           = _data;
1636         ffs->fs_descs_count      = fs_count;
1637         ffs->hs_descs_count      = hs_count;
1638
1639         return 0;
1640
1641 einval:
1642         ret = -EINVAL;
1643 error:
1644         kfree(_data);
1645         return ret;
1646 }
1647
1648 static int __ffs_data_got_strings(struct ffs_data *ffs,
1649                                   char *const _data, size_t len)
1650 {
1651         u32 str_count, needed_count, lang_count;
1652         struct usb_gadget_strings **stringtabs, *t;
1653         struct usb_string *strings, *s;
1654         const char *data = _data;
1655
1656         ENTER();
1657
1658         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
1659                      get_unaligned_le32(data + 4) != len))
1660                 goto error;
1661         str_count  = get_unaligned_le32(data + 8);
1662         lang_count = get_unaligned_le32(data + 12);
1663
1664         /* if one is zero the other must be zero */
1665         if (unlikely(!str_count != !lang_count))
1666                 goto error;
1667
1668         /* Do we have at least as many strings as descriptors need? */
1669         needed_count = ffs->strings_count;
1670         if (unlikely(str_count < needed_count))
1671                 goto error;
1672
1673         /*
1674          * If we don't need any strings just return and free all
1675          * memory.
1676          */
1677         if (!needed_count) {
1678                 kfree(_data);
1679                 return 0;
1680         }
1681
1682         /* Allocate everything in one chunk so there's less maintenance. */
1683         {
1684                 unsigned i = 0;
1685                 vla_group(d);
1686                 vla_item(d, struct usb_gadget_strings *, stringtabs,
1687                         lang_count + 1);
1688                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
1689                 vla_item(d, struct usb_string, strings,
1690                         lang_count*(needed_count+1));
1691
1692                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
1693
1694                 if (unlikely(!vlabuf)) {
1695                         kfree(_data);
1696                         return -ENOMEM;
1697                 }
1698
1699                 /* Initialize the VLA pointers */
1700                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
1701                 t = vla_ptr(vlabuf, d, stringtab);
1702                 i = lang_count;
1703                 do {
1704                         *stringtabs++ = t++;
1705                 } while (--i);
1706                 *stringtabs = NULL;
1707
1708                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
1709                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
1710                 t = vla_ptr(vlabuf, d, stringtab);
1711                 s = vla_ptr(vlabuf, d, strings);
1712                 strings = s;
1713         }
1714
1715         /* For each language */
1716         data += 16;
1717         len -= 16;
1718
1719         do { /* lang_count > 0 so we can use do-while */
1720                 unsigned needed = needed_count;
1721
1722                 if (unlikely(len < 3))
1723                         goto error_free;
1724                 t->language = get_unaligned_le16(data);
1725                 t->strings  = s;
1726                 ++t;
1727
1728                 data += 2;
1729                 len -= 2;
1730
1731                 /* For each string */
1732                 do { /* str_count > 0 so we can use do-while */
1733                         size_t length = strnlen(data, len);
1734
1735                         if (unlikely(length == len))
1736                                 goto error_free;
1737
1738                         /*
1739                          * User may provide more strings then we need,
1740                          * if that's the case we simply ignore the
1741                          * rest
1742                          */
1743                         if (likely(needed)) {
1744                                 /*
1745                                  * s->id will be set while adding
1746                                  * function to configuration so for
1747                                  * now just leave garbage here.
1748                                  */
1749                                 s->s = data;
1750                                 --needed;
1751                                 ++s;
1752                         }
1753
1754                         data += length + 1;
1755                         len -= length + 1;
1756                 } while (--str_count);
1757
1758                 s->id = 0;   /* terminator */
1759                 s->s = NULL;
1760                 ++s;
1761
1762         } while (--lang_count);
1763
1764         /* Some garbage left? */
1765         if (unlikely(len))
1766                 goto error_free;
1767
1768         /* Done! */
1769         ffs->stringtabs = stringtabs;
1770         ffs->raw_strings = _data;
1771
1772         return 0;
1773
1774 error_free:
1775         kfree(stringtabs);
1776 error:
1777         kfree(_data);
1778         return -EINVAL;
1779 }
1780
1781
1782 /* Events handling and management *******************************************/
1783
1784 static void __ffs_event_add(struct ffs_data *ffs,
1785                             enum usb_functionfs_event_type type)
1786 {
1787         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
1788         int neg = 0;
1789
1790         /*
1791          * Abort any unhandled setup
1792          *
1793          * We do not need to worry about some cmpxchg() changing value
1794          * of ffs->setup_state without holding the lock because when
1795          * state is FFS_SETUP_PENDING cmpxchg() in several places in
1796          * the source does nothing.
1797          */
1798         if (ffs->setup_state == FFS_SETUP_PENDING)
1799                 ffs->setup_state = FFS_SETUP_CANCELLED;
1800
1801         switch (type) {
1802         case FUNCTIONFS_RESUME:
1803                 rem_type2 = FUNCTIONFS_SUSPEND;
1804                 /* FALL THROUGH */
1805         case FUNCTIONFS_SUSPEND:
1806         case FUNCTIONFS_SETUP:
1807                 rem_type1 = type;
1808                 /* Discard all similar events */
1809                 break;
1810
1811         case FUNCTIONFS_BIND:
1812         case FUNCTIONFS_UNBIND:
1813         case FUNCTIONFS_DISABLE:
1814         case FUNCTIONFS_ENABLE:
1815                 /* Discard everything other then power management. */
1816                 rem_type1 = FUNCTIONFS_SUSPEND;
1817                 rem_type2 = FUNCTIONFS_RESUME;
1818                 neg = 1;
1819                 break;
1820
1821         default:
1822                 BUG();
1823         }
1824
1825         {
1826                 u8 *ev  = ffs->ev.types, *out = ev;
1827                 unsigned n = ffs->ev.count;
1828                 for (; n; --n, ++ev)
1829                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
1830                                 *out++ = *ev;
1831                         else
1832                                 pr_vdebug("purging event %d\n", *ev);
1833                 ffs->ev.count = out - ffs->ev.types;
1834         }
1835
1836         pr_vdebug("adding event %d\n", type);
1837         ffs->ev.types[ffs->ev.count++] = type;
1838         wake_up_locked(&ffs->ev.waitq);
1839 }
1840
1841 static void ffs_event_add(struct ffs_data *ffs,
1842                           enum usb_functionfs_event_type type)
1843 {
1844         unsigned long flags;
1845         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
1846         __ffs_event_add(ffs, type);
1847         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
1848 }
1849
1850
1851 /* Bind/unbind USB function hooks *******************************************/
1852
1853 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
1854                                     struct usb_descriptor_header *desc,
1855                                     void *priv)
1856 {
1857         struct usb_endpoint_descriptor *ds = (void *)desc;
1858         struct ffs_function *func = priv;
1859         struct ffs_ep *ffs_ep;
1860
1861         /*
1862          * If hs_descriptors is not NULL then we are reading hs
1863          * descriptors now
1864          */
1865         const int isHS = func->function.hs_descriptors != NULL;
1866         unsigned idx;
1867
1868         if (type != FFS_DESCRIPTOR)
1869                 return 0;
1870
1871         if (isHS)
1872                 func->function.hs_descriptors[(long)valuep] = desc;
1873         else
1874                 func->function.fs_descriptors[(long)valuep]    = desc;
1875
1876         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
1877                 return 0;
1878
1879         idx = (ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK) - 1;
1880         ffs_ep = func->eps + idx;
1881
1882         if (unlikely(ffs_ep->descs[isHS])) {
1883                 pr_vdebug("two %sspeed descriptors for EP %d\n",
1884                           isHS ? "high" : "full",
1885                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
1886                 return -EINVAL;
1887         }
1888         ffs_ep->descs[isHS] = ds;
1889
1890         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
1891         if (ffs_ep->ep) {
1892                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
1893                 if (!ds->wMaxPacketSize)
1894                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
1895         } else {
1896                 struct usb_request *req;
1897                 struct usb_ep *ep;
1898
1899                 pr_vdebug("autoconfig\n");
1900                 ep = usb_ep_autoconfig(func->gadget, ds);
1901                 if (unlikely(!ep))
1902                         return -ENOTSUPP;
1903                 ep->driver_data = func->eps + idx;
1904
1905                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
1906                 if (unlikely(!req))
1907                         return -ENOMEM;
1908
1909                 ffs_ep->ep  = ep;
1910                 ffs_ep->req = req;
1911                 func->eps_revmap[ds->bEndpointAddress &
1912                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
1913         }
1914         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
1915
1916         return 0;
1917 }
1918
1919 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
1920                                    struct usb_descriptor_header *desc,
1921                                    void *priv)
1922 {
1923         struct ffs_function *func = priv;
1924         unsigned idx;
1925         u8 newValue;
1926
1927         switch (type) {
1928         default:
1929         case FFS_DESCRIPTOR:
1930                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
1931                 return 0;
1932
1933         case FFS_INTERFACE:
1934                 idx = *valuep;
1935                 if (func->interfaces_nums[idx] < 0) {
1936                         int id = usb_interface_id(func->conf, &func->function);
1937                         if (unlikely(id < 0))
1938                                 return id;
1939                         func->interfaces_nums[idx] = id;
1940                 }
1941                 newValue = func->interfaces_nums[idx];
1942                 break;
1943
1944         case FFS_STRING:
1945                 /* String' IDs are allocated when fsf_data is bound to cdev */
1946                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
1947                 break;
1948
1949         case FFS_ENDPOINT:
1950                 /*
1951                  * USB_DT_ENDPOINT are handled in
1952                  * __ffs_func_bind_do_descs().
1953                  */
1954                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
1955                         return 0;
1956
1957                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
1958                 if (unlikely(!func->eps[idx].ep))
1959                         return -EINVAL;
1960
1961                 {
1962                         struct usb_endpoint_descriptor **descs;
1963                         descs = func->eps[idx].descs;
1964                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
1965                 }
1966                 break;
1967         }
1968
1969         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
1970         *valuep = newValue;
1971         return 0;
1972 }
1973
1974 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
1975                                                 struct usb_configuration *c)
1976 {
1977         struct ffs_function *func = ffs_func_from_usb(f);
1978         struct f_fs_opts *ffs_opts =
1979                 container_of(f->fi, struct f_fs_opts, func_inst);
1980         int ret;
1981
1982         ENTER();
1983
1984         /*
1985          * Legacy gadget triggers binding in functionfs_ready_callback,
1986          * which already uses locking; taking the same lock here would
1987          * cause a deadlock.
1988          *
1989          * Configfs-enabled gadgets however do need ffs_dev_lock.
1990          */
1991         if (!ffs_opts->no_configfs)
1992                 ffs_dev_lock();
1993         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
1994         func->ffs = ffs_opts->dev->ffs_data;
1995         if (!ffs_opts->no_configfs)
1996                 ffs_dev_unlock();
1997         if (ret)
1998                 return ERR_PTR(ret);
1999
2000         func->conf = c;
2001         func->gadget = c->cdev->gadget;
2002
2003         ffs_data_get(func->ffs);
2004
2005         /*
2006          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2007          * configurations are bound in sequence with list_for_each_entry,
2008          * in each configuration its functions are bound in sequence
2009          * with list_for_each_entry, so we assume no race condition
2010          * with regard to ffs_opts->bound access
2011          */
2012         if (!ffs_opts->refcnt) {
2013                 ret = functionfs_bind(func->ffs, c->cdev);
2014                 if (ret)
2015                         return ERR_PTR(ret);
2016         }
2017         ffs_opts->refcnt++;
2018         func->function.strings = func->ffs->stringtabs;
2019
2020         return ffs_opts;
2021 }
2022
2023 static int _ffs_func_bind(struct usb_configuration *c,
2024                           struct usb_function *f)
2025 {
2026         struct ffs_function *func = ffs_func_from_usb(f);
2027         struct ffs_data *ffs = func->ffs;
2028
2029         const int full = !!func->ffs->fs_descs_count;
2030         const int high = gadget_is_dualspeed(func->gadget) &&
2031                 func->ffs->hs_descs_count;
2032
2033         int ret;
2034
2035         /* Make it a single chunk, less management later on */
2036         vla_group(d);
2037         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2038         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2039                 full ? ffs->fs_descs_count + 1 : 0);
2040         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2041                 high ? ffs->hs_descs_count + 1 : 0);
2042         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2043         vla_item_with_sz(d, char, raw_descs,
2044                 high ? ffs->raw_descs_length : ffs->raw_fs_descs_length);
2045         char *vlabuf;
2046
2047         ENTER();
2048
2049         /* Only high speed but not supported by gadget? */
2050         if (unlikely(!(full | high)))
2051                 return -ENOTSUPP;
2052
2053         /* Allocate a single chunk, less management later on */
2054         vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2055         if (unlikely(!vlabuf))
2056                 return -ENOMEM;
2057
2058         /* Zero */
2059         memset(vla_ptr(vlabuf, d, eps), 0, d_eps__sz);
2060         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs + 16,
2061                d_raw_descs__sz);
2062         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2063         for (ret = ffs->eps_count; ret; --ret) {
2064                 struct ffs_ep *ptr;
2065
2066                 ptr = vla_ptr(vlabuf, d, eps);
2067                 ptr[ret].num = -1;
2068         }
2069
2070         /* Save pointers
2071          * d_eps == vlabuf, func->eps used to kfree vlabuf later
2072         */
2073         func->eps             = vla_ptr(vlabuf, d, eps);
2074         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
2075
2076         /*
2077          * Go through all the endpoint descriptors and allocate
2078          * endpoints first, so that later we can rewrite the endpoint
2079          * numbers without worrying that it may be described later on.
2080          */
2081         if (likely(full)) {
2082                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
2083                 ret = ffs_do_descs(ffs->fs_descs_count,
2084                                    vla_ptr(vlabuf, d, raw_descs),
2085                                    d_raw_descs__sz,
2086                                    __ffs_func_bind_do_descs, func);
2087                 if (unlikely(ret < 0))
2088                         goto error;
2089         } else {
2090                 ret = 0;
2091         }
2092
2093         if (likely(high)) {
2094                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
2095                 ret = ffs_do_descs(ffs->hs_descs_count,
2096                                    vla_ptr(vlabuf, d, raw_descs) + ret,
2097                                    d_raw_descs__sz - ret,
2098                                    __ffs_func_bind_do_descs, func);
2099                 if (unlikely(ret < 0))
2100                         goto error;
2101         }
2102
2103         /*
2104          * Now handle interface numbers allocation and interface and
2105          * endpoint numbers rewriting.  We can do that in one go
2106          * now.
2107          */
2108         ret = ffs_do_descs(ffs->fs_descs_count +
2109                            (high ? ffs->hs_descs_count : 0),
2110                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
2111                            __ffs_func_bind_do_nums, func);
2112         if (unlikely(ret < 0))
2113                 goto error;
2114
2115         /* And we're done */
2116         ffs_event_add(ffs, FUNCTIONFS_BIND);
2117         return 0;
2118
2119 error:
2120         /* XXX Do we need to release all claimed endpoints here? */
2121         return ret;
2122 }
2123
2124 static int ffs_func_bind(struct usb_configuration *c,
2125                          struct usb_function *f)
2126 {
2127         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
2128
2129         if (IS_ERR(ffs_opts))
2130                 return PTR_ERR(ffs_opts);
2131
2132         return _ffs_func_bind(c, f);
2133 }
2134
2135
2136 /* Other USB function hooks *************************************************/
2137
2138 static int ffs_func_set_alt(struct usb_function *f,
2139                             unsigned interface, unsigned alt)
2140 {
2141         struct ffs_function *func = ffs_func_from_usb(f);
2142         struct ffs_data *ffs = func->ffs;
2143         int ret = 0, intf;
2144
2145         if (alt != (unsigned)-1) {
2146                 intf = ffs_func_revmap_intf(func, interface);
2147                 if (unlikely(intf < 0))
2148                         return intf;
2149         }
2150
2151         if (ffs->func)
2152                 ffs_func_eps_disable(ffs->func);
2153
2154         if (ffs->state != FFS_ACTIVE)
2155                 return -ENODEV;
2156
2157         if (alt == (unsigned)-1) {
2158                 ffs->func = NULL;
2159                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2160                 return 0;
2161         }
2162
2163         ffs->func = func;
2164         ret = ffs_func_eps_enable(func);
2165         if (likely(ret >= 0))
2166                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2167         return ret;
2168 }
2169
2170 static void ffs_func_disable(struct usb_function *f)
2171 {
2172         ffs_func_set_alt(f, 0, (unsigned)-1);
2173 }
2174
2175 static int ffs_func_setup(struct usb_function *f,
2176                           const struct usb_ctrlrequest *creq)
2177 {
2178         struct ffs_function *func = ffs_func_from_usb(f);
2179         struct ffs_data *ffs = func->ffs;
2180         unsigned long flags;
2181         int ret;
2182
2183         ENTER();
2184
2185         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2186         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2187         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2188         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
2189         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
2190
2191         /*
2192          * Most requests directed to interface go through here
2193          * (notable exceptions are set/get interface) so we need to
2194          * handle them.  All other either handled by composite or
2195          * passed to usb_configuration->setup() (if one is set).  No
2196          * matter, we will handle requests directed to endpoint here
2197          * as well (as it's straightforward) but what to do with any
2198          * other request?
2199          */
2200         if (ffs->state != FFS_ACTIVE)
2201                 return -ENODEV;
2202
2203         switch (creq->bRequestType & USB_RECIP_MASK) {
2204         case USB_RECIP_INTERFACE:
2205                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
2206                 if (unlikely(ret < 0))
2207                         return ret;
2208                 break;
2209
2210         case USB_RECIP_ENDPOINT:
2211                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
2212                 if (unlikely(ret < 0))
2213                         return ret;
2214                 break;
2215
2216         default:
2217                 return -EOPNOTSUPP;
2218         }
2219
2220         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2221         ffs->ev.setup = *creq;
2222         ffs->ev.setup.wIndex = cpu_to_le16(ret);
2223         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
2224         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2225
2226         return 0;
2227 }
2228
2229 static void ffs_func_suspend(struct usb_function *f)
2230 {
2231         ENTER();
2232         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
2233 }
2234
2235 static void ffs_func_resume(struct usb_function *f)
2236 {
2237         ENTER();
2238         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
2239 }
2240
2241
2242 /* Endpoint and interface numbers reverse mapping ***************************/
2243
2244 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
2245 {
2246         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
2247         return num ? num : -EDOM;
2248 }
2249
2250 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
2251 {
2252         short *nums = func->interfaces_nums;
2253         unsigned count = func->ffs->interfaces_count;
2254
2255         for (; count; --count, ++nums) {
2256                 if (*nums >= 0 && *nums == intf)
2257                         return nums - func->interfaces_nums;
2258         }
2259
2260         return -EDOM;
2261 }
2262
2263
2264 /* Devices management *******************************************************/
2265
2266 static LIST_HEAD(ffs_devices);
2267
2268 static struct ffs_dev *_ffs_do_find_dev(const char *name)
2269 {
2270         struct ffs_dev *dev;
2271
2272         list_for_each_entry(dev, &ffs_devices, entry) {
2273                 if (!dev->name || !name)
2274                         continue;
2275                 if (strcmp(dev->name, name) == 0)
2276                         return dev;
2277         }
2278
2279         return NULL;
2280 }
2281
2282 /*
2283  * ffs_lock must be taken by the caller of this function
2284  */
2285 static struct ffs_dev *_ffs_get_single_dev(void)
2286 {
2287         struct ffs_dev *dev;
2288
2289         if (list_is_singular(&ffs_devices)) {
2290                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
2291                 if (dev->single)
2292                         return dev;
2293         }
2294
2295         return NULL;
2296 }
2297
2298 /*
2299  * ffs_lock must be taken by the caller of this function
2300  */
2301 static struct ffs_dev *_ffs_find_dev(const char *name)
2302 {
2303         struct ffs_dev *dev;
2304
2305         dev = _ffs_get_single_dev();
2306         if (dev)
2307                 return dev;
2308
2309         return _ffs_do_find_dev(name);
2310 }
2311
2312 /* Configfs support *********************************************************/
2313
2314 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
2315 {
2316         return container_of(to_config_group(item), struct f_fs_opts,
2317                             func_inst.group);
2318 }
2319
2320 static void ffs_attr_release(struct config_item *item)
2321 {
2322         struct f_fs_opts *opts = to_ffs_opts(item);
2323
2324         usb_put_function_instance(&opts->func_inst);
2325 }
2326
2327 static struct configfs_item_operations ffs_item_ops = {
2328         .release        = ffs_attr_release,
2329 };
2330
2331 static struct config_item_type ffs_func_type = {
2332         .ct_item_ops    = &ffs_item_ops,
2333         .ct_owner       = THIS_MODULE,
2334 };
2335
2336
2337 /* Function registration interface ******************************************/
2338
2339 static void ffs_free_inst(struct usb_function_instance *f)
2340 {
2341         struct f_fs_opts *opts;
2342
2343         opts = to_f_fs_opts(f);
2344         ffs_dev_lock();
2345         _ffs_free_dev(opts->dev);
2346         ffs_dev_unlock();
2347         kfree(opts);
2348 }
2349
2350 #define MAX_INST_NAME_LEN       40
2351
2352 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
2353 {
2354         struct f_fs_opts *opts;
2355         char *ptr;
2356         const char *tmp;
2357         int name_len, ret;
2358
2359         name_len = strlen(name) + 1;
2360         if (name_len > MAX_INST_NAME_LEN)
2361                 return -ENAMETOOLONG;
2362
2363         ptr = kstrndup(name, name_len, GFP_KERNEL);
2364         if (!ptr)
2365                 return -ENOMEM;
2366
2367         opts = to_f_fs_opts(fi);
2368         tmp = NULL;
2369
2370         ffs_dev_lock();
2371
2372         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
2373         ret = _ffs_name_dev(opts->dev, ptr);
2374         if (ret) {
2375                 kfree(ptr);
2376                 ffs_dev_unlock();
2377                 return ret;
2378         }
2379         opts->dev->name_allocated = true;
2380
2381         ffs_dev_unlock();
2382
2383         kfree(tmp);
2384
2385         return 0;
2386 }
2387
2388 static struct usb_function_instance *ffs_alloc_inst(void)
2389 {
2390         struct f_fs_opts *opts;
2391         struct ffs_dev *dev;
2392
2393         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
2394         if (!opts)
2395                 return ERR_PTR(-ENOMEM);
2396
2397         opts->func_inst.set_inst_name = ffs_set_inst_name;
2398         opts->func_inst.free_func_inst = ffs_free_inst;
2399         ffs_dev_lock();
2400         dev = _ffs_alloc_dev();
2401         ffs_dev_unlock();
2402         if (IS_ERR(dev)) {
2403                 kfree(opts);
2404                 return ERR_CAST(dev);
2405         }
2406         opts->dev = dev;
2407         dev->opts = opts;
2408
2409         config_group_init_type_name(&opts->func_inst.group, "",
2410                                     &ffs_func_type);
2411         return &opts->func_inst;
2412 }
2413
2414 static void ffs_free(struct usb_function *f)
2415 {
2416         kfree(ffs_func_from_usb(f));
2417 }
2418
2419 static void ffs_func_unbind(struct usb_configuration *c,
2420                             struct usb_function *f)
2421 {
2422         struct ffs_function *func = ffs_func_from_usb(f);
2423         struct ffs_data *ffs = func->ffs;
2424         struct f_fs_opts *opts =
2425                 container_of(f->fi, struct f_fs_opts, func_inst);
2426         struct ffs_ep *ep = func->eps;
2427         unsigned count = ffs->eps_count;
2428         unsigned long flags;
2429
2430         ENTER();
2431         if (ffs->func == func) {
2432                 ffs_func_eps_disable(func);
2433                 ffs->func = NULL;
2434         }
2435
2436         if (!--opts->refcnt)
2437                 functionfs_unbind(ffs);
2438
2439         /* cleanup after autoconfig */
2440         spin_lock_irqsave(&func->ffs->eps_lock, flags);
2441         do {
2442                 if (ep->ep && ep->req)
2443                         usb_ep_free_request(ep->ep, ep->req);
2444                 ep->req = NULL;
2445                 ++ep;
2446         } while (--count);
2447         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2448         kfree(func->eps);
2449         func->eps = NULL;
2450         /*
2451          * eps, descriptors and interfaces_nums are allocated in the
2452          * same chunk so only one free is required.
2453          */
2454         func->function.fs_descriptors = NULL;
2455         func->function.hs_descriptors = NULL;
2456         func->interfaces_nums = NULL;
2457
2458         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
2459 }
2460
2461 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
2462 {
2463         struct ffs_function *func;
2464
2465         ENTER();
2466
2467         func = kzalloc(sizeof(*func), GFP_KERNEL);
2468         if (unlikely(!func))
2469                 return ERR_PTR(-ENOMEM);
2470
2471         func->function.name    = "Function FS Gadget";
2472
2473         func->function.bind    = ffs_func_bind;
2474         func->function.unbind  = ffs_func_unbind;
2475         func->function.set_alt = ffs_func_set_alt;
2476         func->function.disable = ffs_func_disable;
2477         func->function.setup   = ffs_func_setup;
2478         func->function.suspend = ffs_func_suspend;
2479         func->function.resume  = ffs_func_resume;
2480         func->function.free_func = ffs_free;
2481
2482         return &func->function;
2483 }
2484
2485 /*
2486  * ffs_lock must be taken by the caller of this function
2487  */
2488 static struct ffs_dev *_ffs_alloc_dev(void)
2489 {
2490         struct ffs_dev *dev;
2491         int ret;
2492
2493         if (_ffs_get_single_dev())
2494                         return ERR_PTR(-EBUSY);
2495
2496         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2497         if (!dev)
2498                 return ERR_PTR(-ENOMEM);
2499
2500         if (list_empty(&ffs_devices)) {
2501                 ret = functionfs_init();
2502                 if (ret) {
2503                         kfree(dev);
2504                         return ERR_PTR(ret);
2505                 }
2506         }
2507
2508         list_add(&dev->entry, &ffs_devices);
2509
2510         return dev;
2511 }
2512
2513 /*
2514  * ffs_lock must be taken by the caller of this function
2515  * The caller is responsible for "name" being available whenever f_fs needs it
2516  */
2517 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
2518 {
2519         struct ffs_dev *existing;
2520
2521         existing = _ffs_do_find_dev(name);
2522         if (existing)
2523                 return -EBUSY;
2524
2525         dev->name = name;
2526
2527         return 0;
2528 }
2529
2530 /*
2531  * The caller is responsible for "name" being available whenever f_fs needs it
2532  */
2533 int ffs_name_dev(struct ffs_dev *dev, const char *name)
2534 {
2535         int ret;
2536
2537         ffs_dev_lock();
2538         ret = _ffs_name_dev(dev, name);
2539         ffs_dev_unlock();
2540
2541         return ret;
2542 }
2543 EXPORT_SYMBOL(ffs_name_dev);
2544
2545 int ffs_single_dev(struct ffs_dev *dev)
2546 {
2547         int ret;
2548
2549         ret = 0;
2550         ffs_dev_lock();
2551
2552         if (!list_is_singular(&ffs_devices))
2553                 ret = -EBUSY;
2554         else
2555                 dev->single = true;
2556
2557         ffs_dev_unlock();
2558         return ret;
2559 }
2560 EXPORT_SYMBOL(ffs_single_dev);
2561
2562 /*
2563  * ffs_lock must be taken by the caller of this function
2564  */
2565 static void _ffs_free_dev(struct ffs_dev *dev)
2566 {
2567         list_del(&dev->entry);
2568         if (dev->name_allocated)
2569                 kfree(dev->name);
2570         kfree(dev);
2571         if (list_empty(&ffs_devices))
2572                 functionfs_cleanup();
2573 }
2574
2575 static void *ffs_acquire_dev(const char *dev_name)
2576 {
2577         struct ffs_dev *ffs_dev;
2578
2579         ENTER();
2580         ffs_dev_lock();
2581
2582         ffs_dev = _ffs_find_dev(dev_name);
2583         if (!ffs_dev)
2584                 ffs_dev = ERR_PTR(-ENODEV);
2585         else if (ffs_dev->mounted)
2586                 ffs_dev = ERR_PTR(-EBUSY);
2587         else if (ffs_dev->ffs_acquire_dev_callback &&
2588             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
2589                 ffs_dev = ERR_PTR(-ENODEV);
2590         else
2591                 ffs_dev->mounted = true;
2592
2593         ffs_dev_unlock();
2594         return ffs_dev;
2595 }
2596
2597 static void ffs_release_dev(struct ffs_data *ffs_data)
2598 {
2599         struct ffs_dev *ffs_dev;
2600
2601         ENTER();
2602         ffs_dev_lock();
2603
2604         ffs_dev = ffs_data->private_data;
2605         if (ffs_dev) {
2606                 ffs_dev->mounted = false;
2607
2608                 if (ffs_dev->ffs_release_dev_callback)
2609                         ffs_dev->ffs_release_dev_callback(ffs_dev);
2610         }
2611
2612         ffs_dev_unlock();
2613 }
2614
2615 static int ffs_ready(struct ffs_data *ffs)
2616 {
2617         struct ffs_dev *ffs_obj;
2618         int ret = 0;
2619
2620         ENTER();
2621         ffs_dev_lock();
2622
2623         ffs_obj = ffs->private_data;
2624         if (!ffs_obj) {
2625                 ret = -EINVAL;
2626                 goto done;
2627         }
2628         if (WARN_ON(ffs_obj->desc_ready)) {
2629                 ret = -EBUSY;
2630                 goto done;
2631         }
2632
2633         ffs_obj->desc_ready = true;
2634         ffs_obj->ffs_data = ffs;
2635
2636         if (ffs_obj->ffs_ready_callback)
2637                 ret = ffs_obj->ffs_ready_callback(ffs);
2638
2639 done:
2640         ffs_dev_unlock();
2641         return ret;
2642 }
2643
2644 static void ffs_closed(struct ffs_data *ffs)
2645 {
2646         struct ffs_dev *ffs_obj;
2647
2648         ENTER();
2649         ffs_dev_lock();
2650
2651         ffs_obj = ffs->private_data;
2652         if (!ffs_obj)
2653                 goto done;
2654
2655         ffs_obj->desc_ready = false;
2656
2657         if (ffs_obj->ffs_closed_callback)
2658                 ffs_obj->ffs_closed_callback(ffs);
2659
2660         if (!ffs_obj->opts || ffs_obj->opts->no_configfs
2661             || !ffs_obj->opts->func_inst.group.cg_item.ci_parent)
2662                 goto done;
2663
2664         unregister_gadget_item(ffs_obj->opts->
2665                                func_inst.group.cg_item.ci_parent->ci_parent);
2666 done:
2667         ffs_dev_unlock();
2668 }
2669
2670 /* Misc helper functions ****************************************************/
2671
2672 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
2673 {
2674         return nonblock
2675                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
2676                 : mutex_lock_interruptible(mutex);
2677 }
2678
2679 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
2680 {
2681         char *data;
2682
2683         if (unlikely(!len))
2684                 return NULL;
2685
2686         data = kmalloc(len, GFP_KERNEL);
2687         if (unlikely(!data))
2688                 return ERR_PTR(-ENOMEM);
2689
2690         if (unlikely(__copy_from_user(data, buf, len))) {
2691                 kfree(data);
2692                 return ERR_PTR(-EFAULT);
2693         }
2694
2695         pr_vdebug("Buffer from user space:\n");
2696         ffs_dump_mem("", data, len);
2697
2698         return data;
2699 }
2700
2701 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
2702 MODULE_LICENSE("GPL");
2703 MODULE_AUTHOR("Michal Nazarewicz");