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