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 <linux/aio.h>
  32 #include <linux/mmu_context.h>
  33 #include <linux/poll.h>
  34
  35 #include "u_fs.h"
  36 #include "u_f.h"
  37 #include "configfs.h"
  38
  39 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  40
  41 /* Reference counter handling */
  42 static void ffs_data_get(struct ffs_data *ffs);
  43 static void ffs_data_put(struct ffs_data *ffs);
  44 /* Creates new ffs_data object. */
  45 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
  46
  47 /* Opened counter handling. */
  48 static void ffs_data_opened(struct ffs_data *ffs);
  49 static void ffs_data_closed(struct ffs_data *ffs);
  50
  51 /* Called with ffs->mutex held; take over ownership of data. */
  52 static int __must_check
  53 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  54 static int __must_check
  55 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  56
  57
  58 /* The function structure ***************************************************/
  59
  60 struct ffs_ep;
  61
  62 struct ffs_function {
  63         struct usb_configuration        *conf;
  64         struct usb_gadget               *gadget;
  65         struct ffs_data                 *ffs;
  66
  67         struct ffs_ep                   *eps;
  68         u8                              eps_revmap[16];
  69         short                           *interfaces_nums;
  70
  71         struct usb_function             function;
  72 };
  73
  74
  75 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  76 {
  77         return container_of(f, struct ffs_function, function);
  78 }
  79
  80
  81 static inline enum ffs_setup_state
  82 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  83 {
  84         return (enum ffs_setup_state)
  85                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  86 }
  87
  88
  89 static void ffs_func_eps_disable(struct ffs_function *func);
  90 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  91
  92 static int ffs_func_bind(struct usb_configuration *,
  93                          struct usb_function *);
  94 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
  95 static void ffs_func_disable(struct usb_function *);
  96 static int ffs_func_setup(struct usb_function *,
  97                           const struct usb_ctrlrequest *);
  98 static void ffs_func_suspend(struct usb_function *);
  99 static void ffs_func_resume(struct usb_function *);
 100
 101
 102 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 103 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 104
 105
 106 /* The endpoints structures *************************************************/
 107
 108 struct ffs_ep {
 109         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 110         struct usb_request              *req;   /* P: epfile->mutex */
 111
 112         /* [0]: full speed, [1]: high speed, [2]: super speed */
 113         struct usb_endpoint_descriptor  *descs[3];
 114
 115         u8                              num;
 116
 117         int                             status; /* P: epfile->mutex */
 118 };
 119
 120 struct ffs_epfile {
 121         /* Protects ep->ep and ep->req. */
 122         struct mutex                    mutex;
 123         wait_queue_head_t               wait;
 124
 125         struct ffs_data                 *ffs;
 126         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 127
 128         struct dentry                   *dentry;
 129
 130         char                            name[5];
 131
 132         unsigned char                   in;     /* P: ffs->eps_lock */
 133         unsigned char                   isoc;   /* P: ffs->eps_lock */
 134
 135         unsigned char                   _pad;
 136 };
 137
 138 /*  ffs_io_data structure ***************************************************/
 139
 140 struct ffs_io_data {
 141         bool aio;
 142         bool read;
 143
 144         struct kiocb *kiocb;
 145         const struct iovec *iovec;
 146         unsigned long nr_segs;
 147         char __user *buf;
 148         size_t len;
 149
 150         struct mm_struct *mm;
 151         struct work_struct work;
 152
 153         struct usb_ep *ep;
 154         struct usb_request *req;
 155 };
 156
 157 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 158 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 159
 160 static struct inode *__must_check
 161 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 162                    const struct file_operations *fops,
 163                    struct dentry **dentry_p);
 164
 165 /* Devices management *******************************************************/
 166
 167 DEFINE_MUTEX(ffs_lock);
 168 EXPORT_SYMBOL_GPL(ffs_lock);
 169
 170 static struct ffs_dev *_ffs_find_dev(const char *name);
 171 static struct ffs_dev *_ffs_alloc_dev(void);
 172 static int _ffs_name_dev(struct ffs_dev *dev, const char *name);
 173 static void _ffs_free_dev(struct ffs_dev *dev);
 174 static void *ffs_acquire_dev(const char *dev_name);
 175 static void ffs_release_dev(struct ffs_data *ffs_data);
 176 static int ffs_ready(struct ffs_data *ffs);
 177 static void ffs_closed(struct ffs_data *ffs);
 178
 179 /* Misc helper functions ****************************************************/
 180
 181 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 182         __attribute__((warn_unused_result, nonnull));
 183 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 184         __attribute__((warn_unused_result, nonnull));
 185
 186
 187 /* Control file aka ep0 *****************************************************/
 188
 189 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 190 {
 191         struct ffs_data *ffs = req->context;
 192
 193         complete_all(&ffs->ep0req_completion);
 194 }
 195
 196 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 197 {
 198         struct usb_request *req = ffs->ep0req;
 199         int ret;
 200
 201         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 202
 203         spin_unlock_irq(&ffs->ev.waitq.lock);
 204
 205         req->buf      = data;
 206         req->length   = len;
 207
 208         /*
 209          * UDC layer requires to provide a buffer even for ZLP, but should
 210          * not use it at all. Let's provide some poisoned pointer to catch
 211          * possible bug in the driver.
 212          */
 213         if (req->buf == NULL)
 214                 req->buf = (void *)0xDEADBABE;
 215
 216         reinit_completion(&ffs->ep0req_completion);
 217
 218         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 219         if (unlikely(ret < 0))
 220                 return ret;
 221
 222         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 223         if (unlikely(ret)) {
 224                 usb_ep_dequeue(ffs->gadget->ep0, req);
 225                 return -EINTR;
 226         }
 227
 228         ffs->setup_state = FFS_NO_SETUP;
 229         return req->status ? req->status : req->actual;
 230 }
 231
 232 static int __ffs_ep0_stall(struct ffs_data *ffs)
 233 {
 234         if (ffs->ev.can_stall) {
 235                 pr_vdebug("ep0 stall\n");
 236                 usb_ep_set_halt(ffs->gadget->ep0);
 237                 ffs->setup_state = FFS_NO_SETUP;
 238                 return -EL2HLT;
 239         } else {
 240                 pr_debug("bogus ep0 stall!\n");
 241                 return -ESRCH;
 242         }
 243 }
 244
 245 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 246                              size_t len, loff_t *ptr)
 247 {
 248         struct ffs_data *ffs = file->private_data;
 249         ssize_t ret;
 250         char *data;
 251
 252         ENTER();
 253
 254         /* Fast check if setup was canceled */
 255         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 256                 return -EIDRM;
 257
 258         /* Acquire mutex */
 259         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 260         if (unlikely(ret < 0))
 261                 return ret;
 262
 263         /* Check state */
 264         switch (ffs->state) {
 265         case FFS_READ_DESCRIPTORS:
 266         case FFS_READ_STRINGS:
 267                 /* Copy data */
 268                 if (unlikely(len < 16)) {
 269                         ret = -EINVAL;
 270                         break;
 271                 }
 272
 273                 data = ffs_prepare_buffer(buf, len);
 274                 if (IS_ERR(data)) {
 275                         ret = PTR_ERR(data);
 276                         break;
 277                 }
 278
 279                 /* Handle data */
 280                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 281                         pr_info("read descriptors\n");
 282                         ret = __ffs_data_got_descs(ffs, data, len);
 283                         if (unlikely(ret < 0))
 284                                 break;
 285
 286                         ffs->state = FFS_READ_STRINGS;
 287                         ret = len;
 288                 } else {
 289                         pr_info("read strings\n");
 290                         ret = __ffs_data_got_strings(ffs, data, len);
 291                         if (unlikely(ret < 0))
 292                                 break;
 293
 294                         ret = ffs_epfiles_create(ffs);
 295                         if (unlikely(ret)) {
 296                                 ffs->state = FFS_CLOSING;
 297                                 break;
 298                         }
 299
 300                         ffs->state = FFS_ACTIVE;
 301                         mutex_unlock(&ffs->mutex);
 302
 303                         ret = ffs_ready(ffs);
 304                         if (unlikely(ret < 0)) {
 305                                 ffs->state = FFS_CLOSING;
 306                                 return ret;
 307                         }
 308
 309                         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
 310                         return len;
 311                 }
 312                 break;
 313
 314         case FFS_ACTIVE:
 315                 data = NULL;
 316                 /*
 317                  * We're called from user space, we can use _irq
 318                  * rather then _irqsave
 319                  */
 320                 spin_lock_irq(&ffs->ev.waitq.lock);
 321                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 322                 case FFS_SETUP_CANCELLED:
 323                         ret = -EIDRM;
 324                         goto done_spin;
 325
 326                 case FFS_NO_SETUP:
 327                         ret = -ESRCH;
 328                         goto done_spin;
 329
 330                 case FFS_SETUP_PENDING:
 331                         break;
 332                 }
 333
 334                 /* FFS_SETUP_PENDING */
 335                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 336                         spin_unlock_irq(&ffs->ev.waitq.lock);
 337                         ret = __ffs_ep0_stall(ffs);
 338                         break;
 339                 }
 340
 341                 /* FFS_SETUP_PENDING and not stall */
 342                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 343
 344                 spin_unlock_irq(&ffs->ev.waitq.lock);
 345
 346                 data = ffs_prepare_buffer(buf, len);
 347                 if (IS_ERR(data)) {
 348                         ret = PTR_ERR(data);
 349                         break;
 350                 }
 351
 352                 spin_lock_irq(&ffs->ev.waitq.lock);
 353
 354                 /*
 355                  * We are guaranteed to be still in FFS_ACTIVE state
 356                  * but the state of setup could have changed from
 357                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 358                  * to check for that.  If that happened we copied data
 359                  * from user space in vain but it's unlikely.
 360                  *
 361                  * For sure we are not in FFS_NO_SETUP since this is
 362                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 363                  * transition can be performed and it's protected by
 364                  * mutex.
 365                  */
 366                 if (ffs_setup_state_clear_cancelled(ffs) ==
 367                     FFS_SETUP_CANCELLED) {
 368                         ret = -EIDRM;
 369 done_spin:
 370                         spin_unlock_irq(&ffs->ev.waitq.lock);
 371                 } else {
 372                         /* unlocks spinlock */
 373                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 374                 }
 375                 kfree(data);
 376                 break;
 377
 378         default:
 379                 ret = -EBADFD;
 380                 break;
 381         }
 382
 383         mutex_unlock(&ffs->mutex);
 384         return ret;
 385 }
 386
 387 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 388                                      size_t n)
 389 {
 390         /*
 391          * We are holding ffs->ev.waitq.lock and ffs->mutex and we need
 392          * to release them.
 393          */
 394         struct usb_functionfs_event events[n];
 395         unsigned i = 0;
 396
 397         memset(events, 0, sizeof events);
 398
 399         do {
 400                 events[i].type = ffs->ev.types[i];
 401                 if (events[i].type == FUNCTIONFS_SETUP) {
 402                         events[i].u.setup = ffs->ev.setup;
 403                         ffs->setup_state = FFS_SETUP_PENDING;
 404                 }
 405         } while (++i < n);
 406
 407         if (n < ffs->ev.count) {
 408                 ffs->ev.count -= n;
 409                 memmove(ffs->ev.types, ffs->ev.types + n,
 410                         ffs->ev.count * sizeof *ffs->ev.types);
 411         } else {
 412                 ffs->ev.count = 0;
 413         }
 414
 415         spin_unlock_irq(&ffs->ev.waitq.lock);
 416         mutex_unlock(&ffs->mutex);
 417
 418         return unlikely(__copy_to_user(buf, events, sizeof events))
 419                 ? -EFAULT : sizeof events;
 420 }
 421
 422 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 423                             size_t len, loff_t *ptr)
 424 {
 425         struct ffs_data *ffs = file->private_data;
 426         char *data = NULL;
 427         size_t n;
 428         int ret;
 429
 430         ENTER();
 431
 432         /* Fast check if setup was canceled */
 433         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 434                 return -EIDRM;
 435
 436         /* Acquire mutex */
 437         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 438         if (unlikely(ret < 0))
 439                 return ret;
 440
 441         /* Check state */
 442         if (ffs->state != FFS_ACTIVE) {
 443                 ret = -EBADFD;
 444                 goto done_mutex;
 445         }
 446
 447         /*
 448          * We're called from user space, we can use _irq rather then
 449          * _irqsave
 450          */
 451         spin_lock_irq(&ffs->ev.waitq.lock);
 452
 453         switch (ffs_setup_state_clear_cancelled(ffs)) {
 454         case FFS_SETUP_CANCELLED:
 455                 ret = -EIDRM;
 456                 break;
 457
 458         case FFS_NO_SETUP:
 459                 n = len / sizeof(struct usb_functionfs_event);
 460                 if (unlikely(!n)) {
 461                         ret = -EINVAL;
 462                         break;
 463                 }
 464
 465                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 466                         ret = -EAGAIN;
 467                         break;
 468                 }
 469
 470                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 471                                                         ffs->ev.count)) {
 472                         ret = -EINTR;
 473                         break;
 474                 }
 475
 476                 return __ffs_ep0_read_events(ffs, buf,
 477                                              min(n, (size_t)ffs->ev.count));
 478
 479         case FFS_SETUP_PENDING:
 480                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 481                         spin_unlock_irq(&ffs->ev.waitq.lock);
 482                         ret = __ffs_ep0_stall(ffs);
 483                         goto done_mutex;
 484                 }
 485
 486                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 487
 488                 spin_unlock_irq(&ffs->ev.waitq.lock);
 489
 490                 if (likely(len)) {
 491                         data = kmalloc(len, GFP_KERNEL);
 492                         if (unlikely(!data)) {
 493                                 ret = -ENOMEM;
 494                                 goto done_mutex;
 495                         }
 496                 }
 497
 498                 spin_lock_irq(&ffs->ev.waitq.lock);
 499
 500                 /* See ffs_ep0_write() */
 501                 if (ffs_setup_state_clear_cancelled(ffs) ==
 502                     FFS_SETUP_CANCELLED) {
 503                         ret = -EIDRM;
 504                         break;
 505                 }
 506
 507                 /* unlocks spinlock */
 508                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 509                 if (likely(ret > 0) && unlikely(__copy_to_user(buf, data, len)))
 510                         ret = -EFAULT;
 511                 goto done_mutex;
 512
 513         default:
 514                 ret = -EBADFD;
 515                 break;
 516         }
 517
 518         spin_unlock_irq(&ffs->ev.waitq.lock);
 519 done_mutex:
 520         mutex_unlock(&ffs->mutex);
 521         kfree(data);
 522         return ret;
 523 }
 524
 525 static int ffs_ep0_open(struct inode *inode, struct file *file)
 526 {
 527         struct ffs_data *ffs = inode->i_private;
 528
 529         ENTER();
 530
 531         if (unlikely(ffs->state == FFS_CLOSING))
 532                 return -EBUSY;
 533
 534         file->private_data = ffs;
 535         ffs_data_opened(ffs);
 536
 537         return 0;
 538 }
 539
 540 static int ffs_ep0_release(struct inode *inode, struct file *file)
 541 {
 542         struct ffs_data *ffs = file->private_data;
 543
 544         ENTER();
 545
 546         ffs_data_closed(ffs);
 547
 548         return 0;
 549 }
 550
 551 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 552 {
 553         struct ffs_data *ffs = file->private_data;
 554         struct usb_gadget *gadget = ffs->gadget;
 555         long ret;
 556
 557         ENTER();
 558
 559         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 560                 struct ffs_function *func = ffs->func;
 561                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 562         } else if (gadget && gadget->ops->ioctl) {
 563                 ret = gadget->ops->ioctl(gadget, code, value);
 564         } else {
 565                 ret = -ENOTTY;
 566         }
 567
 568         return ret;
 569 }
 570
 571 static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
 572 {
 573         struct ffs_data *ffs = file->private_data;
 574         unsigned int mask = POLLWRNORM;
 575         int ret;
 576
 577         poll_wait(file, &ffs->ev.waitq, wait);
 578
 579         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 580         if (unlikely(ret < 0))
 581                 return mask;
 582
 583         switch (ffs->state) {
 584         case FFS_READ_DESCRIPTORS:
 585         case FFS_READ_STRINGS:
 586                 mask |= POLLOUT;
 587                 break;
 588
 589         case FFS_ACTIVE:
 590                 switch (ffs->setup_state) {
 591                 case FFS_NO_SETUP:
 592                         if (ffs->ev.count)
 593                                 mask |= POLLIN;
 594                         break;
 595
 596                 case FFS_SETUP_PENDING:
 597                 case FFS_SETUP_CANCELLED:
 598                         mask |= (POLLIN | POLLOUT);
 599                         break;
 600                 }
 601         case FFS_CLOSING:
 602                 break;
 603         }
 604
 605         mutex_unlock(&ffs->mutex);
 606
 607         return mask;
 608 }
 609
 610 static const struct file_operations ffs_ep0_operations = {
 611         .llseek =       no_llseek,
 612
 613         .open =         ffs_ep0_open,
 614         .write =        ffs_ep0_write,
 615         .read =         ffs_ep0_read,
 616         .release =      ffs_ep0_release,
 617         .unlocked_ioctl =       ffs_ep0_ioctl,
 618         .poll =         ffs_ep0_poll,
 619 };
 620
 621
 622 /* "Normal" endpoints operations ********************************************/
 623
 624 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 625 {
 626         ENTER();
 627         if (likely(req->context)) {
 628                 struct ffs_ep *ep = _ep->driver_data;
 629                 ep->status = req->status ? req->status : req->actual;
 630                 complete(req->context);
 631         }
 632 }
 633
 634 static void ffs_user_copy_worker(struct work_struct *work)
 635 {
 636         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 637                                                    work);
 638         int ret = io_data->req->status ? io_data->req->status :
 639                                          io_data->req->actual;
 640
 641         if (io_data->read && ret > 0) {
 642                 int i;
 643                 size_t pos = 0;
 644                 use_mm(io_data->mm);
 645                 for (i = 0; i < io_data->nr_segs; i++) {
 646                         if (unlikely(copy_to_user(io_data->iovec[i].iov_base,
 647                                                  &io_data->buf[pos],
 648                                                  io_data->iovec[i].iov_len))) {
 649                                 ret = -EFAULT;
 650                                 break;
 651                         }
 652                         pos += io_data->iovec[i].iov_len;
 653                 }
 654                 unuse_mm(io_data->mm);
 655         }
 656
 657         aio_complete(io_data->kiocb, ret, ret);
 658
 659         usb_ep_free_request(io_data->ep, io_data->req);
 660
 661         io_data->kiocb->private = NULL;
 662         if (io_data->read)
 663                 kfree(io_data->iovec);
 664         kfree(io_data->buf);
 665         kfree(io_data);
 666 }
 667
 668 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 669                                          struct usb_request *req)
 670 {
 671         struct ffs_io_data *io_data = req->context;
 672
 673         ENTER();
 674
 675         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 676         schedule_work(&io_data->work);
 677 }
 678
 679 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 680 {
 681         struct ffs_epfile *epfile = file->private_data;
 682         struct ffs_ep *ep;
 683         char *data = NULL;
 684         ssize_t ret, data_len;
 685         int halt;
 686
 687         /* Are we still active? */
 688         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
 689                 ret = -ENODEV;
 690                 goto error;
 691         }
 692
 693         /* Wait for endpoint to be enabled */
 694         ep = epfile->ep;
 695         if (!ep) {
 696                 if (file->f_flags & O_NONBLOCK) {
 697                         ret = -EAGAIN;
 698                         goto error;
 699                 }
 700
 701                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
 702                 if (ret) {
 703                         ret = -EINTR;
 704                         goto error;
 705                 }
 706         }
 707
 708         /* Do we halt? */
 709         halt = (!io_data->read == !epfile->in);
 710         if (halt && epfile->isoc) {
 711                 ret = -EINVAL;
 712                 goto error;
 713         }
 714
 715         /* Allocate & copy */
 716         if (!halt) {
 717                 /*
 718                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 719                  * before the waiting completes, so do not assign to 'gadget' earlier
 720                  */
 721                 struct usb_gadget *gadget = epfile->ffs->gadget;
 722
 723                 spin_lock_irq(&epfile->ffs->eps_lock);
 724                 /* In the meantime, endpoint got disabled or changed. */
 725                 if (epfile->ep != ep) {
 726                         spin_unlock_irq(&epfile->ffs->eps_lock);
 727                         return -ESHUTDOWN;
 728                 }
 729                 /*
 730                  * Controller may require buffer size to be aligned to
 731                  * maxpacketsize of an out endpoint.
 732                  */
 733                 data_len = io_data->read ?
 734                            usb_ep_align_maybe(gadget, ep->ep, io_data->len) :
 735                            io_data->len;
 736                 spin_unlock_irq(&epfile->ffs->eps_lock);
 737
 738                 data = kmalloc(data_len, GFP_KERNEL);
 739                 if (unlikely(!data))
 740                         return -ENOMEM;
 741                 if (io_data->aio && !io_data->read) {
 742                         int i;
 743                         size_t pos = 0;
 744                         for (i = 0; i < io_data->nr_segs; i++) {
 745                                 if (unlikely(copy_from_user(&data[pos],
 746                                              io_data->iovec[i].iov_base,
 747                                              io_data->iovec[i].iov_len))) {
 748                                         ret = -EFAULT;
 749                                         goto error;
 750                                 }
 751                                 pos += io_data->iovec[i].iov_len;
 752                         }
 753                 } else {
 754                         if (!io_data->read &&
 755                             unlikely(__copy_from_user(data, io_data->buf,
 756                                                       io_data->len))) {
 757                                 ret = -EFAULT;
 758                                 goto error;
 759                         }
 760                 }
 761         }
 762
 763         /* We will be using request */
 764         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 765         if (unlikely(ret))
 766                 goto error;
 767
 768         spin_lock_irq(&epfile->ffs->eps_lock);
 769
 770         if (epfile->ep != ep) {
 771                 /* In the meantime, endpoint got disabled or changed. */
 772                 ret = -ESHUTDOWN;
 773                 spin_unlock_irq(&epfile->ffs->eps_lock);
 774         } else if (halt) {
 775                 /* Halt */
 776                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 777                         usb_ep_set_halt(ep->ep);
 778                 spin_unlock_irq(&epfile->ffs->eps_lock);
 779                 ret = -EBADMSG;
 780         } else {
 781                 /* Fire the request */
 782                 struct usb_request *req;
 783
 784                 if (io_data->aio) {
 785                         req = usb_ep_alloc_request(ep->ep, GFP_KERNEL);
 786                         if (unlikely(!req))
 787                                 goto error_lock;
 788
 789                         req->buf      = data;
 790                         req->length   = io_data->len;
 791
 792                         io_data->buf = data;
 793                         io_data->ep = ep->ep;
 794                         io_data->req = req;
 795
 796                         req->context  = io_data;
 797                         req->complete = ffs_epfile_async_io_complete;
 798
 799                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 800                         if (unlikely(ret)) {
 801                                 usb_ep_free_request(ep->ep, req);
 802                                 goto error_lock;
 803                         }
 804                         ret = -EIOCBQUEUED;
 805
 806                         spin_unlock_irq(&epfile->ffs->eps_lock);
 807                 } else {
 808                         DECLARE_COMPLETION_ONSTACK(done);
 809
 810                         req = ep->req;
 811                         req->buf      = data;
 812                         req->length   = io_data->len;
 813
 814                         req->context  = &done;
 815                         req->complete = ffs_epfile_io_complete;
 816
 817                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 818
 819                         spin_unlock_irq(&epfile->ffs->eps_lock);
 820
 821                         if (unlikely(ret < 0)) {
 822                                 /* nop */
 823                         } else if (unlikely(
 824                                    wait_for_completion_interruptible(&done))) {
 825                                 ret = -EINTR;
 826                                 usb_ep_dequeue(ep->ep, req);
 827                         } else {
 828                                 /*
 829                                  * XXX We may end up silently droping data
 830                                  * here.  Since data_len (i.e. req->length) may
 831                                  * be bigger than len (after being rounded up
 832                                  * to maxpacketsize), we may end up with more
 833                                  * data then user space has space for.
 834                                  */
 835                                 ret = ep->status;
 836                                 if (io_data->read && ret > 0) {
 837                                         ret = min_t(size_t, ret, io_data->len);
 838
 839                                         if (unlikely(copy_to_user(io_data->buf,
 840                                                 data, ret)))
 841                                                 ret = -EFAULT;
 842                                 }
 843                         }
 844                         kfree(data);
 845                 }
 846         }
 847
 848         mutex_unlock(&epfile->mutex);
 849         return ret;
 850
 851 error_lock:
 852         spin_unlock_irq(&epfile->ffs->eps_lock);
 853         mutex_unlock(&epfile->mutex);
 854 error:
 855         kfree(data);
 856         return ret;
 857 }
 858
 859 static ssize_t
 860 ffs_epfile_write(struct file *file, const char __user *buf, size_t len,
 861                  loff_t *ptr)
 862 {
 863         struct ffs_io_data io_data;
 864
 865         ENTER();
 866
 867         io_data.aio = false;
 868         io_data.read = false;
 869         io_data.buf = (char * __user)buf;
 870         io_data.len = len;
 871
 872         return ffs_epfile_io(file, &io_data);
 873 }
 874
 875 static ssize_t
 876 ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr)
 877 {
 878         struct ffs_io_data io_data;
 879
 880         ENTER();
 881
 882         io_data.aio = false;
 883         io_data.read = true;
 884         io_data.buf = buf;
 885         io_data.len = len;
 886
 887         return ffs_epfile_io(file, &io_data);
 888 }
 889
 890 static int
 891 ffs_epfile_open(struct inode *inode, struct file *file)
 892 {
 893         struct ffs_epfile *epfile = inode->i_private;
 894
 895         ENTER();
 896
 897         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 898                 return -ENODEV;
 899
 900         file->private_data = epfile;
 901         ffs_data_opened(epfile->ffs);
 902
 903         return 0;
 904 }
 905
 906 static int ffs_aio_cancel(struct kiocb *kiocb)
 907 {
 908         struct ffs_io_data *io_data = kiocb->private;
 909         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
 910         int value;
 911
 912         ENTER();
 913
 914         spin_lock_irq(&epfile->ffs->eps_lock);
 915
 916         if (likely(io_data && io_data->ep && io_data->req))
 917                 value = usb_ep_dequeue(io_data->ep, io_data->req);
 918         else
 919                 value = -EINVAL;
 920
 921         spin_unlock_irq(&epfile->ffs->eps_lock);
 922
 923         return value;
 924 }
 925
 926 static ssize_t ffs_epfile_aio_write(struct kiocb *kiocb,
 927                                     const struct iovec *iovec,
 928                                     unsigned long nr_segs, loff_t loff)
 929 {
 930         struct ffs_io_data *io_data;
 931
 932         ENTER();
 933
 934         io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
 935         if (unlikely(!io_data))
 936                 return -ENOMEM;
 937
 938         io_data->aio = true;
 939         io_data->read = false;
 940         io_data->kiocb = kiocb;
 941         io_data->iovec = iovec;
 942         io_data->nr_segs = nr_segs;
 943         io_data->len = kiocb->ki_nbytes;
 944         io_data->mm = current->mm;
 945
 946         kiocb->private = io_data;
 947
 948         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 949
 950         return ffs_epfile_io(kiocb->ki_filp, io_data);
 951 }
 952
 953 static ssize_t ffs_epfile_aio_read(struct kiocb *kiocb,
 954                                    const struct iovec *iovec,
 955                                    unsigned long nr_segs, loff_t loff)
 956 {
 957         struct ffs_io_data *io_data;
 958         struct iovec *iovec_copy;
 959
 960         ENTER();
 961
 962         iovec_copy = kmalloc_array(nr_segs, sizeof(*iovec_copy), GFP_KERNEL);
 963         if (unlikely(!iovec_copy))
 964                 return -ENOMEM;
 965
 966         memcpy(iovec_copy, iovec, sizeof(struct iovec)*nr_segs);
 967
 968         io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
 969         if (unlikely(!io_data)) {
 970                 kfree(iovec_copy);
 971                 return -ENOMEM;
 972         }
 973
 974         io_data->aio = true;
 975         io_data->read = true;
 976         io_data->kiocb = kiocb;
 977         io_data->iovec = iovec_copy;
 978         io_data->nr_segs = nr_segs;
 979         io_data->len = kiocb->ki_nbytes;
 980         io_data->mm = current->mm;
 981
 982         kiocb->private = io_data;
 983
 984         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 985
 986         return ffs_epfile_io(kiocb->ki_filp, io_data);
 987 }
 988
 989 static int
 990 ffs_epfile_release(struct inode *inode, struct file *file)
 991 {
 992         struct ffs_epfile *epfile = inode->i_private;
 993
 994         ENTER();
 995
 996         ffs_data_closed(epfile->ffs);
 997
 998         return 0;
 999 }
1000
1001 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1002                              unsigned long value)
1003 {
1004         struct ffs_epfile *epfile = file->private_data;
1005         int ret;
1006
1007         ENTER();
1008
1009         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1010                 return -ENODEV;
1011
1012         spin_lock_irq(&epfile->ffs->eps_lock);
1013         if (likely(epfile->ep)) {
1014                 switch (code) {
1015                 case FUNCTIONFS_FIFO_STATUS:
1016                         ret = usb_ep_fifo_status(epfile->ep->ep);
1017                         break;
1018                 case FUNCTIONFS_FIFO_FLUSH:
1019                         usb_ep_fifo_flush(epfile->ep->ep);
1020                         ret = 0;
1021                         break;
1022                 case FUNCTIONFS_CLEAR_HALT:
1023                         ret = usb_ep_clear_halt(epfile->ep->ep);
1024                         break;
1025                 case FUNCTIONFS_ENDPOINT_REVMAP:
1026                         ret = epfile->ep->num;
1027                         break;
1028                 default:
1029                         ret = -ENOTTY;
1030                 }
1031         } else {
1032                 ret = -ENODEV;
1033         }
1034         spin_unlock_irq(&epfile->ffs->eps_lock);
1035
1036         return ret;
1037 }
1038
1039 static const struct file_operations ffs_epfile_operations = {
1040         .llseek =       no_llseek,
1041
1042         .open =         ffs_epfile_open,
1043         .write =        ffs_epfile_write,
1044         .read =         ffs_epfile_read,
1045         .aio_write =    ffs_epfile_aio_write,
1046         .aio_read =     ffs_epfile_aio_read,
1047         .release =      ffs_epfile_release,
1048         .unlocked_ioctl =       ffs_epfile_ioctl,
1049 };
1050
1051
1052 /* File system and super block operations ***********************************/
1053
1054 /*
1055  * Mounting the file system creates a controller file, used first for
1056  * function configuration then later for event monitoring.
1057  */
1058
1059 static struct inode *__must_check
1060 ffs_sb_make_inode(struct super_block *sb, void *data,
1061                   const struct file_operations *fops,
1062                   const struct inode_operations *iops,
1063                   struct ffs_file_perms *perms)
1064 {
1065         struct inode *inode;
1066
1067         ENTER();
1068
1069         inode = new_inode(sb);
1070
1071         if (likely(inode)) {
1072                 struct timespec current_time = CURRENT_TIME;
1073
1074                 inode->i_ino     = get_next_ino();
1075                 inode->i_mode    = perms->mode;
1076                 inode->i_uid     = perms->uid;
1077                 inode->i_gid     = perms->gid;
1078                 inode->i_atime   = current_time;
1079                 inode->i_mtime   = current_time;
1080                 inode->i_ctime   = current_time;
1081                 inode->i_private = data;
1082                 if (fops)
1083                         inode->i_fop = fops;
1084                 if (iops)
1085                         inode->i_op  = iops;
1086         }
1087
1088         return inode;
1089 }
1090
1091 /* Create "regular" file */
1092 static struct inode *ffs_sb_create_file(struct super_block *sb,
1093                                         const char *name, void *data,
1094                                         const struct file_operations *fops,
1095                                         struct dentry **dentry_p)
1096 {
1097         struct ffs_data *ffs = sb->s_fs_info;
1098         struct dentry   *dentry;
1099         struct inode    *inode;
1100
1101         ENTER();
1102
1103         dentry = d_alloc_name(sb->s_root, name);
1104         if (unlikely(!dentry))
1105                 return NULL;
1106
1107         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1108         if (unlikely(!inode)) {
1109                 dput(dentry);
1110                 return NULL;
1111         }
1112
1113         d_add(dentry, inode);
1114         if (dentry_p)
1115                 *dentry_p = dentry;
1116
1117         return inode;
1118 }
1119
1120 /* Super block */
1121 static const struct super_operations ffs_sb_operations = {
1122         .statfs =       simple_statfs,
1123         .drop_inode =   generic_delete_inode,
1124 };
1125
1126 struct ffs_sb_fill_data {
1127         struct ffs_file_perms perms;
1128         umode_t root_mode;
1129         const char *dev_name;
1130         struct ffs_data *ffs_data;
1131 };
1132
1133 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1134 {
1135         struct ffs_sb_fill_data *data = _data;
1136         struct inode    *inode;
1137         struct ffs_data *ffs = data->ffs_data;
1138
1139         ENTER();
1140
1141         ffs->sb              = sb;
1142         data->ffs_data       = NULL;
1143         sb->s_fs_info        = ffs;
1144         sb->s_blocksize      = PAGE_CACHE_SIZE;
1145         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1146         sb->s_magic          = FUNCTIONFS_MAGIC;
1147         sb->s_op             = &ffs_sb_operations;
1148         sb->s_time_gran      = 1;
1149
1150         /* Root inode */
1151         data->perms.mode = data->root_mode;
1152         inode = ffs_sb_make_inode(sb, NULL,
1153                                   &simple_dir_operations,
1154                                   &simple_dir_inode_operations,
1155                                   &data->perms);
1156         sb->s_root = d_make_root(inode);
1157         if (unlikely(!sb->s_root))
1158                 return -ENOMEM;
1159
1160         /* EP0 file */
1161         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1162                                          &ffs_ep0_operations, NULL)))
1163                 return -ENOMEM;
1164
1165         return 0;
1166 }
1167
1168 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1169 {
1170         ENTER();
1171
1172         if (!opts || !*opts)
1173                 return 0;
1174
1175         for (;;) {
1176                 unsigned long value;
1177                 char *eq, *comma;
1178
1179                 /* Option limit */
1180                 comma = strchr(opts, ',');
1181                 if (comma)
1182                         *comma = 0;
1183
1184                 /* Value limit */
1185                 eq = strchr(opts, '=');
1186                 if (unlikely(!eq)) {
1187                         pr_err("'=' missing in %s\n", opts);
1188                         return -EINVAL;
1189                 }
1190                 *eq = 0;
1191
1192                 /* Parse value */
1193                 if (kstrtoul(eq + 1, 0, &value)) {
1194                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1195                         return -EINVAL;
1196                 }
1197
1198                 /* Interpret option */
1199                 switch (eq - opts) {
1200                 case 5:
1201                         if (!memcmp(opts, "rmode", 5))
1202                                 data->root_mode  = (value & 0555) | S_IFDIR;
1203                         else if (!memcmp(opts, "fmode", 5))
1204                                 data->perms.mode = (value & 0666) | S_IFREG;
1205                         else
1206                                 goto invalid;
1207                         break;
1208
1209                 case 4:
1210                         if (!memcmp(opts, "mode", 4)) {
1211                                 data->root_mode  = (value & 0555) | S_IFDIR;
1212                                 data->perms.mode = (value & 0666) | S_IFREG;
1213                         } else {
1214                                 goto invalid;
1215                         }
1216                         break;
1217
1218                 case 3:
1219                         if (!memcmp(opts, "uid", 3)) {
1220                                 data->perms.uid = make_kuid(current_user_ns(), value);
1221                                 if (!uid_valid(data->perms.uid)) {
1222                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1223                                         return -EINVAL;
1224                                 }
1225                         } else if (!memcmp(opts, "gid", 3)) {
1226                                 data->perms.gid = make_kgid(current_user_ns(), value);
1227                                 if (!gid_valid(data->perms.gid)) {
1228                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1229                                         return -EINVAL;
1230                                 }
1231                         } else {
1232                                 goto invalid;
1233                         }
1234                         break;
1235
1236                 default:
1237 invalid:
1238                         pr_err("%s: invalid option\n", opts);
1239                         return -EINVAL;
1240                 }
1241
1242                 /* Next iteration */
1243                 if (!comma)
1244                         break;
1245                 opts = comma + 1;
1246         }
1247
1248         return 0;
1249 }
1250
1251 /* "mount -t functionfs dev_name /dev/function" ends up here */
1252
1253 static struct dentry *
1254 ffs_fs_mount(struct file_system_type *t, int flags,
1255               const char *dev_name, void *opts)
1256 {
1257         struct ffs_sb_fill_data data = {
1258                 .perms = {
1259                         .mode = S_IFREG | 0600,
1260                         .uid = GLOBAL_ROOT_UID,
1261                         .gid = GLOBAL_ROOT_GID,
1262                 },
1263                 .root_mode = S_IFDIR | 0500,
1264         };
1265         struct dentry *rv;
1266         int ret;
1267         void *ffs_dev;
1268         struct ffs_data *ffs;
1269
1270         ENTER();
1271
1272         ret = ffs_fs_parse_opts(&data, opts);
1273         if (unlikely(ret < 0))
1274                 return ERR_PTR(ret);
1275
1276         ffs = ffs_data_new();
1277         if (unlikely(!ffs))
1278                 return ERR_PTR(-ENOMEM);
1279         ffs->file_perms = data.perms;
1280
1281         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1282         if (unlikely(!ffs->dev_name)) {
1283                 ffs_data_put(ffs);
1284                 return ERR_PTR(-ENOMEM);
1285         }
1286
1287         ffs_dev = ffs_acquire_dev(dev_name);
1288         if (IS_ERR(ffs_dev)) {
1289                 ffs_data_put(ffs);
1290                 return ERR_CAST(ffs_dev);
1291         }
1292         ffs->private_data = ffs_dev;
1293         data.ffs_data = ffs;
1294
1295         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1296         if (IS_ERR(rv) && data.ffs_data) {
1297                 ffs_release_dev(data.ffs_data);
1298                 ffs_data_put(data.ffs_data);
1299         }
1300         return rv;
1301 }
1302
1303 static void
1304 ffs_fs_kill_sb(struct super_block *sb)
1305 {
1306         ENTER();
1307
1308         kill_litter_super(sb);
1309         if (sb->s_fs_info) {
1310                 ffs_release_dev(sb->s_fs_info);
1311                 ffs_data_put(sb->s_fs_info);
1312         }
1313 }
1314
1315 static struct file_system_type ffs_fs_type = {
1316         .owner          = THIS_MODULE,
1317         .name           = "functionfs",
1318         .mount          = ffs_fs_mount,
1319         .kill_sb        = ffs_fs_kill_sb,
1320 };
1321 MODULE_ALIAS_FS("functionfs");
1322
1323
1324 /* Driver's main init/cleanup functions *************************************/
1325
1326 static int functionfs_init(void)
1327 {
1328         int ret;
1329
1330         ENTER();
1331
1332         ret = register_filesystem(&ffs_fs_type);
1333         if (likely(!ret))
1334                 pr_info("file system registered\n");
1335         else
1336                 pr_err("failed registering file system (%d)\n", ret);
1337
1338         return ret;
1339 }
1340
1341 static void functionfs_cleanup(void)
1342 {
1343         ENTER();
1344
1345         pr_info("unloading\n");
1346         unregister_filesystem(&ffs_fs_type);
1347 }
1348
1349
1350 /* ffs_data and ffs_function construction and destruction code **************/
1351
1352 static void ffs_data_clear(struct ffs_data *ffs);
1353 static void ffs_data_reset(struct ffs_data *ffs);
1354
1355 static void ffs_data_get(struct ffs_data *ffs)
1356 {
1357         ENTER();
1358
1359         atomic_inc(&ffs->ref);
1360 }
1361
1362 static void ffs_data_opened(struct ffs_data *ffs)
1363 {
1364         ENTER();
1365
1366         atomic_inc(&ffs->ref);
1367         atomic_inc(&ffs->opened);
1368 }
1369
1370 static void ffs_data_put(struct ffs_data *ffs)
1371 {
1372         ENTER();
1373
1374         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1375                 pr_info("%s(): freeing\n", __func__);
1376                 ffs_data_clear(ffs);
1377                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1378                        waitqueue_active(&ffs->ep0req_completion.wait));
1379                 kfree(ffs->dev_name);
1380                 kfree(ffs);
1381         }
1382 }
1383
1384 static void ffs_data_closed(struct ffs_data *ffs)
1385 {
1386         ENTER();
1387
1388         if (atomic_dec_and_test(&ffs->opened)) {
1389                 ffs->state = FFS_CLOSING;
1390                 ffs_data_reset(ffs);
1391         }
1392
1393         ffs_data_put(ffs);
1394 }
1395
1396 static struct ffs_data *ffs_data_new(void)
1397 {
1398         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1399         if (unlikely(!ffs))
1400                 return NULL;
1401
1402         ENTER();
1403
1404         atomic_set(&ffs->ref, 1);
1405         atomic_set(&ffs->opened, 0);
1406         ffs->state = FFS_READ_DESCRIPTORS;
1407         mutex_init(&ffs->mutex);
1408         spin_lock_init(&ffs->eps_lock);
1409         init_waitqueue_head(&ffs->ev.waitq);
1410         init_completion(&ffs->ep0req_completion);
1411
1412         /* XXX REVISIT need to update it in some places, or do we? */
1413         ffs->ev.can_stall = 1;
1414
1415         return ffs;
1416 }
1417
1418 static void ffs_data_clear(struct ffs_data *ffs)
1419 {
1420         ENTER();
1421
1422         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags))
1423                 ffs_closed(ffs);
1424
1425         BUG_ON(ffs->gadget);
1426
1427         if (ffs->epfiles)
1428                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1429
1430         kfree(ffs->raw_descs_data);
1431         kfree(ffs->raw_strings);
1432         kfree(ffs->stringtabs);
1433 }
1434
1435 static void ffs_data_reset(struct ffs_data *ffs)
1436 {
1437         ENTER();
1438
1439         ffs_data_clear(ffs);
1440
1441         ffs->epfiles = NULL;
1442         ffs->raw_descs_data = NULL;
1443         ffs->raw_descs = NULL;
1444         ffs->raw_strings = NULL;
1445         ffs->stringtabs = NULL;
1446
1447         ffs->raw_descs_length = 0;
1448         ffs->fs_descs_count = 0;
1449         ffs->hs_descs_count = 0;
1450         ffs->ss_descs_count = 0;
1451
1452         ffs->strings_count = 0;
1453         ffs->interfaces_count = 0;
1454         ffs->eps_count = 0;
1455
1456         ffs->ev.count = 0;
1457
1458         ffs->state = FFS_READ_DESCRIPTORS;
1459         ffs->setup_state = FFS_NO_SETUP;
1460         ffs->flags = 0;
1461 }
1462
1463
1464 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1465 {
1466         struct usb_gadget_strings **lang;
1467         int first_id;
1468
1469         ENTER();
1470
1471         if (WARN_ON(ffs->state != FFS_ACTIVE
1472                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1473                 return -EBADFD;
1474
1475         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1476         if (unlikely(first_id < 0))
1477                 return first_id;
1478
1479         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1480         if (unlikely(!ffs->ep0req))
1481                 return -ENOMEM;
1482         ffs->ep0req->complete = ffs_ep0_complete;
1483         ffs->ep0req->context = ffs;
1484
1485         lang = ffs->stringtabs;
1486         for (lang = ffs->stringtabs; *lang; ++lang) {
1487                 struct usb_string *str = (*lang)->strings;
1488                 int id = first_id;
1489                 for (; str->s; ++id, ++str)
1490                         str->id = id;
1491         }
1492
1493         ffs->gadget = cdev->gadget;
1494         ffs_data_get(ffs);
1495         return 0;
1496 }
1497
1498 static void functionfs_unbind(struct ffs_data *ffs)
1499 {
1500         ENTER();
1501
1502         if (!WARN_ON(!ffs->gadget)) {
1503                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1504                 ffs->ep0req = NULL;
1505                 ffs->gadget = NULL;
1506                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1507                 ffs_data_put(ffs);
1508         }
1509 }
1510
1511 static int ffs_epfiles_create(struct ffs_data *ffs)
1512 {
1513         struct ffs_epfile *epfile, *epfiles;
1514         unsigned i, count;
1515
1516         ENTER();
1517
1518         count = ffs->eps_count;
1519         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1520         if (!epfiles)
1521                 return -ENOMEM;
1522
1523         epfile = epfiles;
1524         for (i = 1; i <= count; ++i, ++epfile) {
1525                 epfile->ffs = ffs;
1526                 mutex_init(&epfile->mutex);
1527                 init_waitqueue_head(&epfile->wait);
1528                 sprintf(epfiles->name, "ep%u",  i);
1529                 if (!unlikely(ffs_sb_create_file(ffs->sb, epfiles->name, epfile,
1530                                                  &ffs_epfile_operations,
1531                                                  &epfile->dentry))) {
1532                         ffs_epfiles_destroy(epfiles, i - 1);
1533                         return -ENOMEM;
1534                 }
1535         }
1536
1537         ffs->epfiles = epfiles;
1538         return 0;
1539 }
1540
1541 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1542 {
1543         struct ffs_epfile *epfile = epfiles;
1544
1545         ENTER();
1546
1547         for (; count; --count, ++epfile) {
1548                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1549                        waitqueue_active(&epfile->wait));
1550                 if (epfile->dentry) {
1551                         d_delete(epfile->dentry);
1552                         dput(epfile->dentry);
1553                         epfile->dentry = NULL;
1554                 }
1555         }
1556
1557         kfree(epfiles);
1558 }
1559
1560
1561 static void ffs_func_eps_disable(struct ffs_function *func)
1562 {
1563         struct ffs_ep *ep         = func->eps;
1564         struct ffs_epfile *epfile = func->ffs->epfiles;
1565         unsigned count            = func->ffs->eps_count;
1566         unsigned long flags;
1567
1568         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1569         do {
1570                 /* pending requests get nuked */
1571                 if (likely(ep->ep))
1572                         usb_ep_disable(ep->ep);
1573                 epfile->ep = NULL;
1574
1575                 ++ep;
1576                 ++epfile;
1577         } while (--count);
1578         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1579 }
1580
1581 static int ffs_func_eps_enable(struct ffs_function *func)
1582 {
1583         struct ffs_data *ffs      = func->ffs;
1584         struct ffs_ep *ep         = func->eps;
1585         struct ffs_epfile *epfile = ffs->epfiles;
1586         unsigned count            = ffs->eps_count;
1587         unsigned long flags;
1588         int ret = 0;
1589
1590         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1591         do {
1592                 struct usb_endpoint_descriptor *ds;
1593                 int desc_idx;
1594
1595                 if (ffs->gadget->speed == USB_SPEED_SUPER)
1596                         desc_idx = 2;
1597                 else if (ffs->gadget->speed == USB_SPEED_HIGH)
1598                         desc_idx = 1;
1599                 else
1600                         desc_idx = 0;
1601
1602                 /* fall-back to lower speed if desc missing for current speed */
1603                 do {
1604                         ds = ep->descs[desc_idx];
1605                 } while (!ds && --desc_idx >= 0);
1606
1607                 if (!ds) {
1608                         ret = -EINVAL;
1609                         break;
1610                 }
1611
1612                 ep->ep->driver_data = ep;
1613                 ep->ep->desc = ds;
1614                 ret = usb_ep_enable(ep->ep);
1615                 if (likely(!ret)) {
1616                         epfile->ep = ep;
1617                         epfile->in = usb_endpoint_dir_in(ds);
1618                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1619                 } else {
1620                         break;
1621                 }
1622
1623                 wake_up(&epfile->wait);
1624
1625                 ++ep;
1626                 ++epfile;
1627         } while (--count);
1628         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1629
1630         return ret;
1631 }
1632
1633
1634 /* Parsing and building descriptors and strings *****************************/
1635
1636 /*
1637  * This validates if data pointed by data is a valid USB descriptor as
1638  * well as record how many interfaces, endpoints and strings are
1639  * required by given configuration.  Returns address after the
1640  * descriptor or NULL if data is invalid.
1641  */
1642
1643 enum ffs_entity_type {
1644         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1645 };
1646
1647 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1648                                    u8 *valuep,
1649                                    struct usb_descriptor_header *desc,
1650                                    void *priv);
1651
1652 static int __must_check ffs_do_desc(char *data, unsigned len,
1653                                     ffs_entity_callback entity, void *priv)
1654 {
1655         struct usb_descriptor_header *_ds = (void *)data;
1656         u8 length;
1657         int ret;
1658
1659         ENTER();
1660
1661         /* At least two bytes are required: length and type */
1662         if (len < 2) {
1663                 pr_vdebug("descriptor too short\n");
1664                 return -EINVAL;
1665         }
1666
1667         /* If we have at least as many bytes as the descriptor takes? */
1668         length = _ds->bLength;
1669         if (len < length) {
1670                 pr_vdebug("descriptor longer then available data\n");
1671                 return -EINVAL;
1672         }
1673
1674 #define __entity_check_INTERFACE(val)  1
1675 #define __entity_check_STRING(val)     (val)
1676 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1677 #define __entity(type, val) do {                                        \
1678                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1679                 if (unlikely(!__entity_check_ ##type(val))) {           \
1680                         pr_vdebug("invalid entity's value\n");          \
1681                         return -EINVAL;                                 \
1682                 }                                                       \
1683                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1684                 if (unlikely(ret < 0)) {                                \
1685                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1686                                  (val), ret);                           \
1687                         return ret;                                     \
1688                 }                                                       \
1689         } while (0)
1690
1691         /* Parse descriptor depending on type. */
1692         switch (_ds->bDescriptorType) {
1693         case USB_DT_DEVICE:
1694         case USB_DT_CONFIG:
1695         case USB_DT_STRING:
1696         case USB_DT_DEVICE_QUALIFIER:
1697                 /* function can't have any of those */
1698                 pr_vdebug("descriptor reserved for gadget: %d\n",
1699                       _ds->bDescriptorType);
1700                 return -EINVAL;
1701
1702         case USB_DT_INTERFACE: {
1703                 struct usb_interface_descriptor *ds = (void *)_ds;
1704                 pr_vdebug("interface descriptor\n");
1705                 if (length != sizeof *ds)
1706                         goto inv_length;
1707
1708                 __entity(INTERFACE, ds->bInterfaceNumber);
1709                 if (ds->iInterface)
1710                         __entity(STRING, ds->iInterface);
1711         }
1712                 break;
1713
1714         case USB_DT_ENDPOINT: {
1715                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1716                 pr_vdebug("endpoint descriptor\n");
1717                 if (length != USB_DT_ENDPOINT_SIZE &&
1718                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1719                         goto inv_length;
1720                 __entity(ENDPOINT, ds->bEndpointAddress);
1721         }
1722                 break;
1723
1724         case HID_DT_HID:
1725                 pr_vdebug("hid descriptor\n");
1726                 if (length != sizeof(struct hid_descriptor))
1727                         goto inv_length;
1728                 break;
1729
1730         case USB_DT_OTG:
1731                 if (length != sizeof(struct usb_otg_descriptor))
1732                         goto inv_length;
1733                 break;
1734
1735         case USB_DT_INTERFACE_ASSOCIATION: {
1736                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1737                 pr_vdebug("interface association descriptor\n");
1738                 if (length != sizeof *ds)
1739                         goto inv_length;
1740                 if (ds->iFunction)
1741                         __entity(STRING, ds->iFunction);
1742         }
1743                 break;
1744
1745         case USB_DT_SS_ENDPOINT_COMP:
1746                 pr_vdebug("EP SS companion descriptor\n");
1747                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
1748                         goto inv_length;
1749                 break;
1750
1751         case USB_DT_OTHER_SPEED_CONFIG:
1752         case USB_DT_INTERFACE_POWER:
1753         case USB_DT_DEBUG:
1754         case USB_DT_SECURITY:
1755         case USB_DT_CS_RADIO_CONTROL:
1756                 /* TODO */
1757                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1758                 return -EINVAL;
1759
1760         default:
1761                 /* We should never be here */
1762                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1763                 return -EINVAL;
1764
1765 inv_length:
1766                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1767                           _ds->bLength, _ds->bDescriptorType);
1768                 return -EINVAL;
1769         }
1770
1771 #undef __entity
1772 #undef __entity_check_DESCRIPTOR
1773 #undef __entity_check_INTERFACE
1774 #undef __entity_check_STRING
1775 #undef __entity_check_ENDPOINT
1776
1777         return length;
1778 }
1779
1780 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1781                                      ffs_entity_callback entity, void *priv)
1782 {
1783         const unsigned _len = len;
1784         unsigned long num = 0;
1785
1786         ENTER();
1787
1788         for (;;) {
1789                 int ret;
1790
1791                 if (num == count)
1792                         data = NULL;
1793
1794                 /* Record "descriptor" entity */
1795                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1796                 if (unlikely(ret < 0)) {
1797                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1798                                  num, ret);
1799                         return ret;
1800                 }
1801
1802                 if (!data)
1803                         return _len - len;
1804
1805                 ret = ffs_do_desc(data, len, entity, priv);
1806                 if (unlikely(ret < 0)) {
1807                         pr_debug("%s returns %d\n", __func__, ret);
1808                         return ret;
1809                 }
1810
1811                 len -= ret;
1812                 data += ret;
1813                 ++num;
1814         }
1815 }
1816
1817 static int __ffs_data_do_entity(enum ffs_entity_type type,
1818                                 u8 *valuep, struct usb_descriptor_header *desc,
1819                                 void *priv)
1820 {
1821         struct ffs_data *ffs = priv;
1822
1823         ENTER();
1824
1825         switch (type) {
1826         case FFS_DESCRIPTOR:
1827                 break;
1828
1829         case FFS_INTERFACE:
1830                 /*
1831                  * Interfaces are indexed from zero so if we
1832                  * encountered interface "n" then there are at least
1833                  * "n+1" interfaces.
1834                  */
1835                 if (*valuep >= ffs->interfaces_count)
1836                         ffs->interfaces_count = *valuep + 1;
1837                 break;
1838
1839         case FFS_STRING:
1840                 /*
1841                  * Strings are indexed from 1 (0 is magic ;) reserved
1842                  * for languages list or some such)
1843                  */
1844                 if (*valuep > ffs->strings_count)
1845                         ffs->strings_count = *valuep;
1846                 break;
1847
1848         case FFS_ENDPOINT:
1849                 /* Endpoints are indexed from 1 as well. */
1850                 if ((*valuep & USB_ENDPOINT_NUMBER_MASK) > ffs->eps_count)
1851                         ffs->eps_count = (*valuep & USB_ENDPOINT_NUMBER_MASK);
1852                 break;
1853         }
1854
1855         return 0;
1856 }
1857
1858 static int __ffs_data_got_descs(struct ffs_data *ffs,
1859                                 char *const _data, size_t len)
1860 {
1861         char *data = _data, *raw_descs;
1862         unsigned counts[3], flags;
1863         int ret = -EINVAL, i;
1864
1865         ENTER();
1866
1867         if (get_unaligned_le32(data + 4) != len)
1868                 goto error;
1869
1870         switch (get_unaligned_le32(data)) {
1871         case FUNCTIONFS_DESCRIPTORS_MAGIC:
1872                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
1873                 data += 8;
1874                 len  -= 8;
1875                 break;
1876         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
1877                 flags = get_unaligned_le32(data + 8);
1878                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
1879                               FUNCTIONFS_HAS_HS_DESC |
1880                               FUNCTIONFS_HAS_SS_DESC)) {
1881                         ret = -ENOSYS;
1882                         goto error;
1883                 }
1884                 data += 12;
1885                 len  -= 12;
1886                 break;
1887         default:
1888                 goto error;
1889         }
1890
1891         /* Read fs_count, hs_count and ss_count (if present) */
1892         for (i = 0; i < 3; ++i) {
1893                 if (!(flags & (1 << i))) {
1894                         counts[i] = 0;
1895                 } else if (len < 4) {
1896                         goto error;
1897                 } else {
1898                         counts[i] = get_unaligned_le32(data);
1899                         data += 4;
1900                         len  -= 4;
1901                 }
1902         }
1903
1904         /* Read descriptors */
1905         raw_descs = data;
1906         for (i = 0; i < 3; ++i) {
1907                 if (!counts[i])
1908                         continue;
1909                 ret = ffs_do_descs(counts[i], data, len,
1910                                    __ffs_data_do_entity, ffs);
1911                 if (ret < 0)
1912                         goto error;
1913                 data += ret;
1914                 len  -= ret;
1915         }
1916
1917         if (raw_descs == data || len) {
1918                 ret = -EINVAL;
1919                 goto error;
1920         }
1921
1922         ffs->raw_descs_data     = _data;
1923         ffs->raw_descs          = raw_descs;
1924         ffs->raw_descs_length   = data - raw_descs;
1925         ffs->fs_descs_count     = counts[0];
1926         ffs->hs_descs_count     = counts[1];
1927         ffs->ss_descs_count     = counts[2];
1928
1929         return 0;
1930
1931 error:
1932         kfree(_data);
1933         return ret;
1934 }
1935
1936 static int __ffs_data_got_strings(struct ffs_data *ffs,
1937                                   char *const _data, size_t len)
1938 {
1939         u32 str_count, needed_count, lang_count;
1940         struct usb_gadget_strings **stringtabs, *t;
1941         struct usb_string *strings, *s;
1942         const char *data = _data;
1943
1944         ENTER();
1945
1946         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
1947                      get_unaligned_le32(data + 4) != len))
1948                 goto error;
1949         str_count  = get_unaligned_le32(data + 8);
1950         lang_count = get_unaligned_le32(data + 12);
1951
1952         /* if one is zero the other must be zero */
1953         if (unlikely(!str_count != !lang_count))
1954                 goto error;
1955
1956         /* Do we have at least as many strings as descriptors need? */
1957         needed_count = ffs->strings_count;
1958         if (unlikely(str_count < needed_count))
1959                 goto error;
1960
1961         /*
1962          * If we don't need any strings just return and free all
1963          * memory.
1964          */
1965         if (!needed_count) {
1966                 kfree(_data);
1967                 return 0;
1968         }
1969
1970         /* Allocate everything in one chunk so there's less maintenance. */
1971         {
1972                 unsigned i = 0;
1973                 vla_group(d);
1974                 vla_item(d, struct usb_gadget_strings *, stringtabs,
1975                         lang_count + 1);
1976                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
1977                 vla_item(d, struct usb_string, strings,
1978                         lang_count*(needed_count+1));
1979
1980                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
1981
1982                 if (unlikely(!vlabuf)) {
1983                         kfree(_data);
1984                         return -ENOMEM;
1985                 }
1986
1987                 /* Initialize the VLA pointers */
1988                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
1989                 t = vla_ptr(vlabuf, d, stringtab);
1990                 i = lang_count;
1991                 do {
1992                         *stringtabs++ = t++;
1993                 } while (--i);
1994                 *stringtabs = NULL;
1995
1996                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
1997                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
1998                 t = vla_ptr(vlabuf, d, stringtab);
1999                 s = vla_ptr(vlabuf, d, strings);
2000                 strings = s;
2001         }
2002
2003         /* For each language */
2004         data += 16;
2005         len -= 16;
2006
2007         do { /* lang_count > 0 so we can use do-while */
2008                 unsigned needed = needed_count;
2009
2010                 if (unlikely(len < 3))
2011                         goto error_free;
2012                 t->language = get_unaligned_le16(data);
2013                 t->strings  = s;
2014                 ++t;
2015
2016                 data += 2;
2017                 len -= 2;
2018
2019                 /* For each string */
2020                 do { /* str_count > 0 so we can use do-while */
2021                         size_t length = strnlen(data, len);
2022
2023                         if (unlikely(length == len))
2024                                 goto error_free;
2025
2026                         /*
2027                          * User may provide more strings then we need,
2028                          * if that's the case we simply ignore the
2029                          * rest
2030                          */
2031                         if (likely(needed)) {
2032                                 /*
2033                                  * s->id will be set while adding
2034                                  * function to configuration so for
2035                                  * now just leave garbage here.
2036                                  */
2037                                 s->s = data;
2038                                 --needed;
2039                                 ++s;
2040                         }
2041
2042                         data += length + 1;
2043                         len -= length + 1;
2044                 } while (--str_count);
2045
2046                 s->id = 0;   /* terminator */
2047                 s->s = NULL;
2048                 ++s;
2049
2050         } while (--lang_count);
2051
2052         /* Some garbage left? */
2053         if (unlikely(len))
2054                 goto error_free;
2055
2056         /* Done! */
2057         ffs->stringtabs = stringtabs;
2058         ffs->raw_strings = _data;
2059
2060         return 0;
2061
2062 error_free:
2063         kfree(stringtabs);
2064 error:
2065         kfree(_data);
2066         return -EINVAL;
2067 }
2068
2069
2070 /* Events handling and management *******************************************/
2071
2072 static void __ffs_event_add(struct ffs_data *ffs,
2073                             enum usb_functionfs_event_type type)
2074 {
2075         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2076         int neg = 0;
2077
2078         /*
2079          * Abort any unhandled setup
2080          *
2081          * We do not need to worry about some cmpxchg() changing value
2082          * of ffs->setup_state without holding the lock because when
2083          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2084          * the source does nothing.
2085          */
2086         if (ffs->setup_state == FFS_SETUP_PENDING)
2087                 ffs->setup_state = FFS_SETUP_CANCELLED;
2088
2089         switch (type) {
2090         case FUNCTIONFS_RESUME:
2091                 rem_type2 = FUNCTIONFS_SUSPEND;
2092                 /* FALL THROUGH */
2093         case FUNCTIONFS_SUSPEND:
2094         case FUNCTIONFS_SETUP:
2095                 rem_type1 = type;
2096                 /* Discard all similar events */
2097                 break;
2098
2099         case FUNCTIONFS_BIND:
2100         case FUNCTIONFS_UNBIND:
2101         case FUNCTIONFS_DISABLE:
2102         case FUNCTIONFS_ENABLE:
2103                 /* Discard everything other then power management. */
2104                 rem_type1 = FUNCTIONFS_SUSPEND;
2105                 rem_type2 = FUNCTIONFS_RESUME;
2106                 neg = 1;
2107                 break;
2108
2109         default:
2110                 BUG();
2111         }
2112
2113         {
2114                 u8 *ev  = ffs->ev.types, *out = ev;
2115                 unsigned n = ffs->ev.count;
2116                 for (; n; --n, ++ev)
2117                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2118                                 *out++ = *ev;
2119                         else
2120                                 pr_vdebug("purging event %d\n", *ev);
2121                 ffs->ev.count = out - ffs->ev.types;
2122         }
2123
2124         pr_vdebug("adding event %d\n", type);
2125         ffs->ev.types[ffs->ev.count++] = type;
2126         wake_up_locked(&ffs->ev.waitq);
2127 }
2128
2129 static void ffs_event_add(struct ffs_data *ffs,
2130                           enum usb_functionfs_event_type type)
2131 {
2132         unsigned long flags;
2133         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2134         __ffs_event_add(ffs, type);
2135         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2136 }
2137
2138
2139 /* Bind/unbind USB function hooks *******************************************/
2140
2141 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2142                                     struct usb_descriptor_header *desc,
2143                                     void *priv)
2144 {
2145         struct usb_endpoint_descriptor *ds = (void *)desc;
2146         struct ffs_function *func = priv;
2147         struct ffs_ep *ffs_ep;
2148         unsigned ep_desc_id, idx;
2149         static const char *speed_names[] = { "full", "high", "super" };
2150
2151         if (type != FFS_DESCRIPTOR)
2152                 return 0;
2153
2154         /*
2155          * If ss_descriptors is not NULL, we are reading super speed
2156          * descriptors; if hs_descriptors is not NULL, we are reading high
2157          * speed descriptors; otherwise, we are reading full speed
2158          * descriptors.
2159          */
2160         if (func->function.ss_descriptors) {
2161                 ep_desc_id = 2;
2162                 func->function.ss_descriptors[(long)valuep] = desc;
2163         } else if (func->function.hs_descriptors) {
2164                 ep_desc_id = 1;
2165                 func->function.hs_descriptors[(long)valuep] = desc;
2166         } else {
2167                 ep_desc_id = 0;
2168                 func->function.fs_descriptors[(long)valuep]    = desc;
2169         }
2170
2171         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2172                 return 0;
2173
2174         idx = (ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK) - 1;
2175         ffs_ep = func->eps + idx;
2176
2177         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2178                 pr_err("two %sspeed descriptors for EP %d\n",
2179                           speed_names[ep_desc_id],
2180                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2181                 return -EINVAL;
2182         }
2183         ffs_ep->descs[ep_desc_id] = ds;
2184
2185         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2186         if (ffs_ep->ep) {
2187                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2188                 if (!ds->wMaxPacketSize)
2189                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2190         } else {
2191                 struct usb_request *req;
2192                 struct usb_ep *ep;
2193
2194                 pr_vdebug("autoconfig\n");
2195                 ep = usb_ep_autoconfig(func->gadget, ds);
2196                 if (unlikely(!ep))
2197                         return -ENOTSUPP;
2198                 ep->driver_data = func->eps + idx;
2199
2200                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2201                 if (unlikely(!req))
2202                         return -ENOMEM;
2203
2204                 ffs_ep->ep  = ep;
2205                 ffs_ep->req = req;
2206                 func->eps_revmap[ds->bEndpointAddress &
2207                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2208         }
2209         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2210
2211         return 0;
2212 }
2213
2214 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2215                                    struct usb_descriptor_header *desc,
2216                                    void *priv)
2217 {
2218         struct ffs_function *func = priv;
2219         unsigned idx;
2220         u8 newValue;
2221
2222         switch (type) {
2223         default:
2224         case FFS_DESCRIPTOR:
2225                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2226                 return 0;
2227
2228         case FFS_INTERFACE:
2229                 idx = *valuep;
2230                 if (func->interfaces_nums[idx] < 0) {
2231                         int id = usb_interface_id(func->conf, &func->function);
2232                         if (unlikely(id < 0))
2233                                 return id;
2234                         func->interfaces_nums[idx] = id;
2235                 }
2236                 newValue = func->interfaces_nums[idx];
2237                 break;
2238
2239         case FFS_STRING:
2240                 /* String' IDs are allocated when fsf_data is bound to cdev */
2241                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2242                 break;
2243
2244         case FFS_ENDPOINT:
2245                 /*
2246                  * USB_DT_ENDPOINT are handled in
2247                  * __ffs_func_bind_do_descs().
2248                  */
2249                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2250                         return 0;
2251
2252                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2253                 if (unlikely(!func->eps[idx].ep))
2254                         return -EINVAL;
2255
2256                 {
2257                         struct usb_endpoint_descriptor **descs;
2258                         descs = func->eps[idx].descs;
2259                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2260                 }
2261                 break;
2262         }
2263
2264         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2265         *valuep = newValue;
2266         return 0;
2267 }
2268
2269 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2270                                                 struct usb_configuration *c)
2271 {
2272         struct ffs_function *func = ffs_func_from_usb(f);
2273         struct f_fs_opts *ffs_opts =
2274                 container_of(f->fi, struct f_fs_opts, func_inst);
2275         int ret;
2276
2277         ENTER();
2278
2279         /*
2280          * Legacy gadget triggers binding in functionfs_ready_callback,
2281          * which already uses locking; taking the same lock here would
2282          * cause a deadlock.
2283          *
2284          * Configfs-enabled gadgets however do need ffs_dev_lock.
2285          */
2286         if (!ffs_opts->no_configfs)
2287                 ffs_dev_lock();
2288         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2289         func->ffs = ffs_opts->dev->ffs_data;
2290         if (!ffs_opts->no_configfs)
2291                 ffs_dev_unlock();
2292         if (ret)
2293                 return ERR_PTR(ret);
2294
2295         func->conf = c;
2296         func->gadget = c->cdev->gadget;
2297
2298         ffs_data_get(func->ffs);
2299
2300         /*
2301          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2302          * configurations are bound in sequence with list_for_each_entry,
2303          * in each configuration its functions are bound in sequence
2304          * with list_for_each_entry, so we assume no race condition
2305          * with regard to ffs_opts->bound access
2306          */
2307         if (!ffs_opts->refcnt) {
2308                 ret = functionfs_bind(func->ffs, c->cdev);
2309                 if (ret)
2310                         return ERR_PTR(ret);
2311         }
2312         ffs_opts->refcnt++;
2313         func->function.strings = func->ffs->stringtabs;
2314
2315         return ffs_opts;
2316 }
2317
2318 static int _ffs_func_bind(struct usb_configuration *c,
2319                           struct usb_function *f)
2320 {
2321         struct ffs_function *func = ffs_func_from_usb(f);
2322         struct ffs_data *ffs = func->ffs;
2323
2324         const int full = !!func->ffs->fs_descs_count;
2325         const int high = gadget_is_dualspeed(func->gadget) &&
2326                 func->ffs->hs_descs_count;
2327         const int super = gadget_is_superspeed(func->gadget) &&
2328                 func->ffs->ss_descs_count;
2329
2330         int fs_len, hs_len, ret;
2331
2332         /* Make it a single chunk, less management later on */
2333         vla_group(d);
2334         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2335         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2336                 full ? ffs->fs_descs_count + 1 : 0);
2337         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2338                 high ? ffs->hs_descs_count + 1 : 0);
2339         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2340                 super ? ffs->ss_descs_count + 1 : 0);
2341         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2342         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2343         char *vlabuf;
2344
2345         ENTER();
2346
2347         /* Has descriptors only for speeds gadget does not support */
2348         if (unlikely(!(full | high | super)))
2349                 return -ENOTSUPP;
2350
2351         /* Allocate a single chunk, less management later on */
2352         vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2353         if (unlikely(!vlabuf))
2354                 return -ENOMEM;
2355
2356         /* Zero */
2357         memset(vla_ptr(vlabuf, d, eps), 0, d_eps__sz);
2358         /* Copy descriptors  */
2359         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
2360                ffs->raw_descs_length);
2361
2362         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2363         for (ret = ffs->eps_count; ret; --ret) {
2364                 struct ffs_ep *ptr;
2365
2366                 ptr = vla_ptr(vlabuf, d, eps);
2367                 ptr[ret].num = -1;
2368         }
2369
2370         /* Save pointers
2371          * d_eps == vlabuf, func->eps used to kfree vlabuf later
2372         */
2373         func->eps             = vla_ptr(vlabuf, d, eps);
2374         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
2375
2376         /*
2377          * Go through all the endpoint descriptors and allocate
2378          * endpoints first, so that later we can rewrite the endpoint
2379          * numbers without worrying that it may be described later on.
2380          */
2381         if (likely(full)) {
2382                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
2383                 fs_len = ffs_do_descs(ffs->fs_descs_count,
2384                                       vla_ptr(vlabuf, d, raw_descs),
2385                                       d_raw_descs__sz,
2386                                       __ffs_func_bind_do_descs, func);
2387                 if (unlikely(fs_len < 0)) {
2388                         ret = fs_len;
2389                         goto error;
2390                 }
2391         } else {
2392                 fs_len = 0;
2393         }
2394
2395         if (likely(high)) {
2396                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
2397                 hs_len = ffs_do_descs(ffs->hs_descs_count,
2398                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
2399                                       d_raw_descs__sz - fs_len,
2400                                       __ffs_func_bind_do_descs, func);
2401                 if (unlikely(hs_len < 0)) {
2402                         ret = hs_len;
2403                         goto error;
2404                 }
2405         } else {
2406                 hs_len = 0;
2407         }
2408
2409         if (likely(super)) {
2410                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
2411                 ret = ffs_do_descs(ffs->ss_descs_count,
2412                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
2413                                 d_raw_descs__sz - fs_len - hs_len,
2414                                 __ffs_func_bind_do_descs, func);
2415                 if (unlikely(ret < 0))
2416                         goto error;
2417         }
2418
2419         /*
2420          * Now handle interface numbers allocation and interface and
2421          * endpoint numbers rewriting.  We can do that in one go
2422          * now.
2423          */
2424         ret = ffs_do_descs(ffs->fs_descs_count +
2425                            (high ? ffs->hs_descs_count : 0) +
2426                            (super ? ffs->ss_descs_count : 0),
2427                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
2428                            __ffs_func_bind_do_nums, func);
2429         if (unlikely(ret < 0))
2430                 goto error;
2431
2432         /* And we're done */
2433         ffs_event_add(ffs, FUNCTIONFS_BIND);
2434         return 0;
2435
2436 error:
2437         /* XXX Do we need to release all claimed endpoints here? */
2438         return ret;
2439 }
2440
2441 static int ffs_func_bind(struct usb_configuration *c,
2442                          struct usb_function *f)
2443 {
2444         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
2445
2446         if (IS_ERR(ffs_opts))
2447                 return PTR_ERR(ffs_opts);
2448
2449         return _ffs_func_bind(c, f);
2450 }
2451
2452
2453 /* Other USB function hooks *************************************************/
2454
2455 static int ffs_func_set_alt(struct usb_function *f,
2456                             unsigned interface, unsigned alt)
2457 {
2458         struct ffs_function *func = ffs_func_from_usb(f);
2459         struct ffs_data *ffs = func->ffs;
2460         int ret = 0, intf;
2461
2462         if (alt != (unsigned)-1) {
2463                 intf = ffs_func_revmap_intf(func, interface);
2464                 if (unlikely(intf < 0))
2465                         return intf;
2466         }
2467
2468         if (ffs->func)
2469                 ffs_func_eps_disable(ffs->func);
2470
2471         if (ffs->state != FFS_ACTIVE)
2472                 return -ENODEV;
2473
2474         if (alt == (unsigned)-1) {
2475                 ffs->func = NULL;
2476                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2477                 return 0;
2478         }
2479
2480         ffs->func = func;
2481         ret = ffs_func_eps_enable(func);
2482         if (likely(ret >= 0))
2483                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2484         return ret;
2485 }
2486
2487 static void ffs_func_disable(struct usb_function *f)
2488 {
2489         ffs_func_set_alt(f, 0, (unsigned)-1);
2490 }
2491
2492 static int ffs_func_setup(struct usb_function *f,
2493                           const struct usb_ctrlrequest *creq)
2494 {
2495         struct ffs_function *func = ffs_func_from_usb(f);
2496         struct ffs_data *ffs = func->ffs;
2497         unsigned long flags;
2498         int ret;
2499
2500         ENTER();
2501
2502         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2503         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2504         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2505         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
2506         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
2507
2508         /*
2509          * Most requests directed to interface go through here
2510          * (notable exceptions are set/get interface) so we need to
2511          * handle them.  All other either handled by composite or
2512          * passed to usb_configuration->setup() (if one is set).  No
2513          * matter, we will handle requests directed to endpoint here
2514          * as well (as it's straightforward) but what to do with any
2515          * other request?
2516          */
2517         if (ffs->state != FFS_ACTIVE)
2518                 return -ENODEV;
2519
2520         switch (creq->bRequestType & USB_RECIP_MASK) {
2521         case USB_RECIP_INTERFACE:
2522                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
2523                 if (unlikely(ret < 0))
2524                         return ret;
2525                 break;
2526
2527         case USB_RECIP_ENDPOINT:
2528                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
2529                 if (unlikely(ret < 0))
2530                         return ret;
2531                 break;
2532
2533         default:
2534                 return -EOPNOTSUPP;
2535         }
2536
2537         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2538         ffs->ev.setup = *creq;
2539         ffs->ev.setup.wIndex = cpu_to_le16(ret);
2540         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
2541         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2542
2543         return 0;
2544 }
2545
2546 static void ffs_func_suspend(struct usb_function *f)
2547 {
2548         ENTER();
2549         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
2550 }
2551
2552 static void ffs_func_resume(struct usb_function *f)
2553 {
2554         ENTER();
2555         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
2556 }
2557
2558
2559 /* Endpoint and interface numbers reverse mapping ***************************/
2560
2561 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
2562 {
2563         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
2564         return num ? num : -EDOM;
2565 }
2566
2567 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
2568 {
2569         short *nums = func->interfaces_nums;
2570         unsigned count = func->ffs->interfaces_count;
2571
2572         for (; count; --count, ++nums) {
2573                 if (*nums >= 0 && *nums == intf)
2574                         return nums - func->interfaces_nums;
2575         }
2576
2577         return -EDOM;
2578 }
2579
2580
2581 /* Devices management *******************************************************/
2582
2583 static LIST_HEAD(ffs_devices);
2584
2585 static struct ffs_dev *_ffs_do_find_dev(const char *name)
2586 {
2587         struct ffs_dev *dev;
2588
2589         list_for_each_entry(dev, &ffs_devices, entry) {
2590                 if (!dev->name || !name)
2591                         continue;
2592                 if (strcmp(dev->name, name) == 0)
2593                         return dev;
2594         }
2595
2596         return NULL;
2597 }
2598
2599 /*
2600  * ffs_lock must be taken by the caller of this function
2601  */
2602 static struct ffs_dev *_ffs_get_single_dev(void)
2603 {
2604         struct ffs_dev *dev;
2605
2606         if (list_is_singular(&ffs_devices)) {
2607                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
2608                 if (dev->single)
2609                         return dev;
2610         }
2611
2612         return NULL;
2613 }
2614
2615 /*
2616  * ffs_lock must be taken by the caller of this function
2617  */
2618 static struct ffs_dev *_ffs_find_dev(const char *name)
2619 {
2620         struct ffs_dev *dev;
2621
2622         dev = _ffs_get_single_dev();
2623         if (dev)
2624                 return dev;
2625
2626         return _ffs_do_find_dev(name);
2627 }
2628
2629 /* Configfs support *********************************************************/
2630
2631 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
2632 {
2633         return container_of(to_config_group(item), struct f_fs_opts,
2634                             func_inst.group);
2635 }
2636
2637 static void ffs_attr_release(struct config_item *item)
2638 {
2639         struct f_fs_opts *opts = to_ffs_opts(item);
2640
2641         usb_put_function_instance(&opts->func_inst);
2642 }
2643
2644 static struct configfs_item_operations ffs_item_ops = {
2645         .release        = ffs_attr_release,
2646 };
2647
2648 static struct config_item_type ffs_func_type = {
2649         .ct_item_ops    = &ffs_item_ops,
2650         .ct_owner       = THIS_MODULE,
2651 };
2652
2653
2654 /* Function registration interface ******************************************/
2655
2656 static void ffs_free_inst(struct usb_function_instance *f)
2657 {
2658         struct f_fs_opts *opts;
2659
2660         opts = to_f_fs_opts(f);
2661         ffs_dev_lock();
2662         _ffs_free_dev(opts->dev);
2663         ffs_dev_unlock();
2664         kfree(opts);
2665 }
2666
2667 #define MAX_INST_NAME_LEN       40
2668
2669 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
2670 {
2671         struct f_fs_opts *opts;
2672         char *ptr;
2673         const char *tmp;
2674         int name_len, ret;
2675
2676         name_len = strlen(name) + 1;
2677         if (name_len > MAX_INST_NAME_LEN)
2678                 return -ENAMETOOLONG;
2679
2680         ptr = kstrndup(name, name_len, GFP_KERNEL);
2681         if (!ptr)
2682                 return -ENOMEM;
2683
2684         opts = to_f_fs_opts(fi);
2685         tmp = NULL;
2686
2687         ffs_dev_lock();
2688
2689         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
2690         ret = _ffs_name_dev(opts->dev, ptr);
2691         if (ret) {
2692                 kfree(ptr);
2693                 ffs_dev_unlock();
2694                 return ret;
2695         }
2696         opts->dev->name_allocated = true;
2697
2698         ffs_dev_unlock();
2699
2700         kfree(tmp);
2701
2702         return 0;
2703 }
2704
2705 static struct usb_function_instance *ffs_alloc_inst(void)
2706 {
2707         struct f_fs_opts *opts;
2708         struct ffs_dev *dev;
2709
2710         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
2711         if (!opts)
2712                 return ERR_PTR(-ENOMEM);
2713
2714         opts->func_inst.set_inst_name = ffs_set_inst_name;
2715         opts->func_inst.free_func_inst = ffs_free_inst;
2716         ffs_dev_lock();
2717         dev = _ffs_alloc_dev();
2718         ffs_dev_unlock();
2719         if (IS_ERR(dev)) {
2720                 kfree(opts);
2721                 return ERR_CAST(dev);
2722         }
2723         opts->dev = dev;
2724         dev->opts = opts;
2725
2726         config_group_init_type_name(&opts->func_inst.group, "",
2727                                     &ffs_func_type);
2728         return &opts->func_inst;
2729 }
2730
2731 static void ffs_free(struct usb_function *f)
2732 {
2733         kfree(ffs_func_from_usb(f));
2734 }
2735
2736 static void ffs_func_unbind(struct usb_configuration *c,
2737                             struct usb_function *f)
2738 {
2739         struct ffs_function *func = ffs_func_from_usb(f);
2740         struct ffs_data *ffs = func->ffs;
2741         struct f_fs_opts *opts =
2742                 container_of(f->fi, struct f_fs_opts, func_inst);
2743         struct ffs_ep *ep = func->eps;
2744         unsigned count = ffs->eps_count;
2745         unsigned long flags;
2746
2747         ENTER();
2748         if (ffs->func == func) {
2749                 ffs_func_eps_disable(func);
2750                 ffs->func = NULL;
2751         }
2752
2753         if (!--opts->refcnt)
2754                 functionfs_unbind(ffs);
2755
2756         /* cleanup after autoconfig */
2757         spin_lock_irqsave(&func->ffs->eps_lock, flags);
2758         do {
2759                 if (ep->ep && ep->req)
2760                         usb_ep_free_request(ep->ep, ep->req);
2761                 ep->req = NULL;
2762                 ++ep;
2763         } while (--count);
2764         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2765         kfree(func->eps);
2766         func->eps = NULL;
2767         /*
2768          * eps, descriptors and interfaces_nums are allocated in the
2769          * same chunk so only one free is required.
2770          */
2771         func->function.fs_descriptors = NULL;
2772         func->function.hs_descriptors = NULL;
2773         func->function.ss_descriptors = NULL;
2774         func->interfaces_nums = NULL;
2775
2776         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
2777 }
2778
2779 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
2780 {
2781         struct ffs_function *func;
2782
2783         ENTER();
2784
2785         func = kzalloc(sizeof(*func), GFP_KERNEL);
2786         if (unlikely(!func))
2787                 return ERR_PTR(-ENOMEM);
2788
2789         func->function.name    = "Function FS Gadget";
2790
2791         func->function.bind    = ffs_func_bind;
2792         func->function.unbind  = ffs_func_unbind;
2793         func->function.set_alt = ffs_func_set_alt;
2794         func->function.disable = ffs_func_disable;
2795         func->function.setup   = ffs_func_setup;
2796         func->function.suspend = ffs_func_suspend;
2797         func->function.resume  = ffs_func_resume;
2798         func->function.free_func = ffs_free;
2799
2800         return &func->function;
2801 }
2802
2803 /*
2804  * ffs_lock must be taken by the caller of this function
2805  */
2806 static struct ffs_dev *_ffs_alloc_dev(void)
2807 {
2808         struct ffs_dev *dev;
2809         int ret;
2810
2811         if (_ffs_get_single_dev())
2812                         return ERR_PTR(-EBUSY);
2813
2814         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2815         if (!dev)
2816                 return ERR_PTR(-ENOMEM);
2817
2818         if (list_empty(&ffs_devices)) {
2819                 ret = functionfs_init();
2820                 if (ret) {
2821                         kfree(dev);
2822                         return ERR_PTR(ret);
2823                 }
2824         }
2825
2826         list_add(&dev->entry, &ffs_devices);
2827
2828         return dev;
2829 }
2830
2831 /*
2832  * ffs_lock must be taken by the caller of this function
2833  * The caller is responsible for "name" being available whenever f_fs needs it
2834  */
2835 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
2836 {
2837         struct ffs_dev *existing;
2838
2839         existing = _ffs_do_find_dev(name);
2840         if (existing)
2841                 return -EBUSY;
2842
2843         dev->name = name;
2844
2845         return 0;
2846 }
2847
2848 /*
2849  * The caller is responsible for "name" being available whenever f_fs needs it
2850  */
2851 int ffs_name_dev(struct ffs_dev *dev, const char *name)
2852 {
2853         int ret;
2854
2855         ffs_dev_lock();
2856         ret = _ffs_name_dev(dev, name);
2857         ffs_dev_unlock();
2858
2859         return ret;
2860 }
2861 EXPORT_SYMBOL_GPL(ffs_name_dev);
2862
2863 int ffs_single_dev(struct ffs_dev *dev)
2864 {
2865         int ret;
2866
2867         ret = 0;
2868         ffs_dev_lock();
2869
2870         if (!list_is_singular(&ffs_devices))
2871                 ret = -EBUSY;
2872         else
2873                 dev->single = true;
2874
2875         ffs_dev_unlock();
2876         return ret;
2877 }
2878 EXPORT_SYMBOL_GPL(ffs_single_dev);
2879
2880 /*
2881  * ffs_lock must be taken by the caller of this function
2882  */
2883 static void _ffs_free_dev(struct ffs_dev *dev)
2884 {
2885         list_del(&dev->entry);
2886         if (dev->name_allocated)
2887                 kfree(dev->name);
2888         kfree(dev);
2889         if (list_empty(&ffs_devices))
2890                 functionfs_cleanup();
2891 }
2892
2893 static void *ffs_acquire_dev(const char *dev_name)
2894 {
2895         struct ffs_dev *ffs_dev;
2896
2897         ENTER();
2898         ffs_dev_lock();
2899
2900         ffs_dev = _ffs_find_dev(dev_name);
2901         if (!ffs_dev)
2902                 ffs_dev = ERR_PTR(-ENODEV);
2903         else if (ffs_dev->mounted)
2904                 ffs_dev = ERR_PTR(-EBUSY);
2905         else if (ffs_dev->ffs_acquire_dev_callback &&
2906             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
2907                 ffs_dev = ERR_PTR(-ENODEV);
2908         else
2909                 ffs_dev->mounted = true;
2910
2911         ffs_dev_unlock();
2912         return ffs_dev;
2913 }
2914
2915 static void ffs_release_dev(struct ffs_data *ffs_data)
2916 {
2917         struct ffs_dev *ffs_dev;
2918
2919         ENTER();
2920         ffs_dev_lock();
2921
2922         ffs_dev = ffs_data->private_data;
2923         if (ffs_dev) {
2924                 ffs_dev->mounted = false;
2925
2926                 if (ffs_dev->ffs_release_dev_callback)
2927                         ffs_dev->ffs_release_dev_callback(ffs_dev);
2928         }
2929
2930         ffs_dev_unlock();
2931 }
2932
2933 static int ffs_ready(struct ffs_data *ffs)
2934 {
2935         struct ffs_dev *ffs_obj;
2936         int ret = 0;
2937
2938         ENTER();
2939         ffs_dev_lock();
2940
2941         ffs_obj = ffs->private_data;
2942         if (!ffs_obj) {
2943                 ret = -EINVAL;
2944                 goto done;
2945         }
2946         if (WARN_ON(ffs_obj->desc_ready)) {
2947                 ret = -EBUSY;
2948                 goto done;
2949         }
2950
2951         ffs_obj->desc_ready = true;
2952         ffs_obj->ffs_data = ffs;
2953
2954         if (ffs_obj->ffs_ready_callback)
2955                 ret = ffs_obj->ffs_ready_callback(ffs);
2956
2957 done:
2958         ffs_dev_unlock();
2959         return ret;
2960 }
2961
2962 static void ffs_closed(struct ffs_data *ffs)
2963 {
2964         struct ffs_dev *ffs_obj;
2965
2966         ENTER();
2967         ffs_dev_lock();
2968
2969         ffs_obj = ffs->private_data;
2970         if (!ffs_obj)
2971                 goto done;
2972
2973         ffs_obj->desc_ready = false;
2974
2975         if (ffs_obj->ffs_closed_callback)
2976                 ffs_obj->ffs_closed_callback(ffs);
2977
2978         if (!ffs_obj->opts || ffs_obj->opts->no_configfs
2979             || !ffs_obj->opts->func_inst.group.cg_item.ci_parent)
2980                 goto done;
2981
2982         unregister_gadget_item(ffs_obj->opts->
2983                                func_inst.group.cg_item.ci_parent->ci_parent);
2984 done:
2985         ffs_dev_unlock();
2986 }
2987
2988 /* Misc helper functions ****************************************************/
2989
2990 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
2991 {
2992         return nonblock
2993                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
2994                 : mutex_lock_interruptible(mutex);
2995 }
2996
2997 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
2998 {
2999         char *data;
3000
3001         if (unlikely(!len))
3002                 return NULL;
3003
3004         data = kmalloc(len, GFP_KERNEL);
3005         if (unlikely(!data))
3006                 return ERR_PTR(-ENOMEM);
3007
3008         if (unlikely(__copy_from_user(data, buf, len))) {
3009                 kfree(data);
3010                 return ERR_PTR(-EFAULT);
3011         }
3012
3013         pr_vdebug("Buffer from user space:\n");
3014         ffs_dump_mem("", data, len);
3015
3016         return data;
3017 }
3018
3019 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3020 MODULE_LICENSE("GPL");
3021 MODULE_AUTHOR("Michal Nazarewicz");