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 "configfs.h"
  37
  38 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  39
  40 /* Variable Length Array Macros **********************************************/
  41 #define vla_group(groupname) size_t groupname##__next = 0
  42 #define vla_group_size(groupname) groupname##__next
  43
  44 #define vla_item(groupname, type, name, n) \
  45         size_t groupname##_##name##__offset = ({                               \
  46                 size_t align_mask = __alignof__(type) - 1;                     \
  47                 size_t offset = (groupname##__next + align_mask) & ~align_mask;\
  48                 size_t size = (n) * sizeof(type);                              \
  49                 groupname##__next = offset + size;                             \
  50                 offset;                                                        \
  51         })
  52
  53 #define vla_item_with_sz(groupname, type, name, n) \
  54         size_t groupname##_##name##__sz = (n) * sizeof(type);                  \
  55         size_t groupname##_##name##__offset = ({                               \
  56                 size_t align_mask = __alignof__(type) - 1;                     \
  57                 size_t offset = (groupname##__next + align_mask) & ~align_mask;\
  58                 size_t size = groupname##_##name##__sz;                        \
  59                 groupname##__next = offset + size;                             \
  60                 offset;                                                        \
  61         })
  62
  63 #define vla_ptr(ptr, groupname, name) \
  64         ((void *) ((char *)ptr + groupname##_##name##__offset))
  65
  66 /* Reference counter handling */
  67 static void ffs_data_get(struct ffs_data *ffs);
  68 static void ffs_data_put(struct ffs_data *ffs);
  69 /* Creates new ffs_data object. */
  70 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
  71
  72 /* Opened counter handling. */
  73 static void ffs_data_opened(struct ffs_data *ffs);
  74 static void ffs_data_closed(struct ffs_data *ffs);
  75
  76 /* Called with ffs->mutex held; take over ownership of data. */
  77 static int __must_check
  78 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  79 static int __must_check
  80 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  81
  82
  83 /* The function structure ***************************************************/
  84
  85 struct ffs_ep;
  86
  87 struct ffs_function {
  88         struct usb_configuration        *conf;
  89         struct usb_gadget               *gadget;
  90         struct ffs_data                 *ffs;
  91
  92         struct ffs_ep                   *eps;
  93         u8                              eps_revmap[16];
  94         short                           *interfaces_nums;
  95
  96         struct usb_function             function;
  97 };
  98
  99
 100 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
 101 {
 102         return container_of(f, struct ffs_function, function);
 103 }
 104
 105
 106 static inline enum ffs_setup_state
 107 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
 108 {
 109         return (enum ffs_setup_state)
 110                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
 111 }
 112
 113
 114 static void ffs_func_eps_disable(struct ffs_function *func);
 115 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
 116
 117 static int ffs_func_bind(struct usb_configuration *,
 118                          struct usb_function *);
 119 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 120 static void ffs_func_disable(struct usb_function *);
 121 static int ffs_func_setup(struct usb_function *,
 122                           const struct usb_ctrlrequest *);
 123 static void ffs_func_suspend(struct usb_function *);
 124 static void ffs_func_resume(struct usb_function *);
 125
 126
 127 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 128 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 129
 130
 131 /* The endpoints structures *************************************************/
 132
 133 struct ffs_ep {
 134         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 135         struct usb_request              *req;   /* P: epfile->mutex */
 136
 137         /* [0]: full speed, [1]: high speed, [2]: super speed */
 138         struct usb_endpoint_descriptor  *descs[3];
 139
 140         u8                              num;
 141
 142         int                             status; /* P: epfile->mutex */
 143 };
 144
 145 struct ffs_epfile {
 146         /* Protects ep->ep and ep->req. */
 147         struct mutex                    mutex;
 148         wait_queue_head_t               wait;
 149
 150         struct ffs_data                 *ffs;
 151         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 152
 153         struct dentry                   *dentry;
 154
 155         char                            name[5];
 156
 157         unsigned char                   in;     /* P: ffs->eps_lock */
 158         unsigned char                   isoc;   /* P: ffs->eps_lock */
 159
 160         unsigned char                   _pad;
 161 };
 162
 163 /*  ffs_io_data structure ***************************************************/
 164
 165 struct ffs_io_data {
 166         bool aio;
 167         bool read;
 168
 169         struct kiocb *kiocb;
 170         const struct iovec *iovec;
 171         unsigned long nr_segs;
 172         char __user *buf;
 173         size_t len;
 174
 175         struct mm_struct *mm;
 176         struct work_struct work;
 177
 178         struct usb_ep *ep;
 179         struct usb_request *req;
 180 };
 181
 182 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 183 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 184
 185 static struct inode *__must_check
 186 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 187                    const struct file_operations *fops,
 188                    struct dentry **dentry_p);
 189
 190 /* Devices management *******************************************************/
 191
 192 DEFINE_MUTEX(ffs_lock);
 193 EXPORT_SYMBOL(ffs_lock);
 194
 195 static struct ffs_dev *_ffs_find_dev(const char *name);
 196 static struct ffs_dev *_ffs_alloc_dev(void);
 197 static int _ffs_name_dev(struct ffs_dev *dev, const char *name);
 198 static void _ffs_free_dev(struct ffs_dev *dev);
 199 static void *ffs_acquire_dev(const char *dev_name);
 200 static void ffs_release_dev(struct ffs_data *ffs_data);
 201 static int ffs_ready(struct ffs_data *ffs);
 202 static void ffs_closed(struct ffs_data *ffs);
 203
 204 /* Misc helper functions ****************************************************/
 205
 206 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 207         __attribute__((warn_unused_result, nonnull));
 208 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 209         __attribute__((warn_unused_result, nonnull));
 210
 211
 212 /* Control file aka ep0 *****************************************************/
 213
 214 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 215 {
 216         struct ffs_data *ffs = req->context;
 217
 218         complete_all(&ffs->ep0req_completion);
 219 }
 220
 221 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 222 {
 223         struct usb_request *req = ffs->ep0req;
 224         int ret;
 225
 226         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 227
 228         spin_unlock_irq(&ffs->ev.waitq.lock);
 229
 230         req->buf      = data;
 231         req->length   = len;
 232
 233         /*
 234          * UDC layer requires to provide a buffer even for ZLP, but should
 235          * not use it at all. Let's provide some poisoned pointer to catch
 236          * possible bug in the driver.
 237          */
 238         if (req->buf == NULL)
 239                 req->buf = (void *)0xDEADBABE;
 240
 241         reinit_completion(&ffs->ep0req_completion);
 242
 243         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 244         if (unlikely(ret < 0))
 245                 return ret;
 246
 247         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 248         if (unlikely(ret)) {
 249                 usb_ep_dequeue(ffs->gadget->ep0, req);
 250                 return -EINTR;
 251         }
 252
 253         ffs->setup_state = FFS_NO_SETUP;
 254         return req->status ? req->status : req->actual;
 255 }
 256
 257 static int __ffs_ep0_stall(struct ffs_data *ffs)
 258 {
 259         if (ffs->ev.can_stall) {
 260                 pr_vdebug("ep0 stall\n");
 261                 usb_ep_set_halt(ffs->gadget->ep0);
 262                 ffs->setup_state = FFS_NO_SETUP;
 263                 return -EL2HLT;
 264         } else {
 265                 pr_debug("bogus ep0 stall!\n");
 266                 return -ESRCH;
 267         }
 268 }
 269
 270 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 271                              size_t len, loff_t *ptr)
 272 {
 273         struct ffs_data *ffs = file->private_data;
 274         ssize_t ret;
 275         char *data;
 276
 277         ENTER();
 278
 279         /* Fast check if setup was canceled */
 280         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 281                 return -EIDRM;
 282
 283         /* Acquire mutex */
 284         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 285         if (unlikely(ret < 0))
 286                 return ret;
 287
 288         /* Check state */
 289         switch (ffs->state) {
 290         case FFS_READ_DESCRIPTORS:
 291         case FFS_READ_STRINGS:
 292                 /* Copy data */
 293                 if (unlikely(len < 16)) {
 294                         ret = -EINVAL;
 295                         break;
 296                 }
 297
 298                 data = ffs_prepare_buffer(buf, len);
 299                 if (IS_ERR(data)) {
 300                         ret = PTR_ERR(data);
 301                         break;
 302                 }
 303
 304                 /* Handle data */
 305                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 306                         pr_info("read descriptors\n");
 307                         ret = __ffs_data_got_descs(ffs, data, len);
 308                         if (unlikely(ret < 0))
 309                                 break;
 310
 311                         ffs->state = FFS_READ_STRINGS;
 312                         ret = len;
 313                 } else {
 314                         pr_info("read strings\n");
 315                         ret = __ffs_data_got_strings(ffs, data, len);
 316                         if (unlikely(ret < 0))
 317                                 break;
 318
 319                         ret = ffs_epfiles_create(ffs);
 320                         if (unlikely(ret)) {
 321                                 ffs->state = FFS_CLOSING;
 322                                 break;
 323                         }
 324
 325                         ffs->state = FFS_ACTIVE;
 326                         mutex_unlock(&ffs->mutex);
 327
 328                         ret = ffs_ready(ffs);
 329                         if (unlikely(ret < 0)) {
 330                                 ffs->state = FFS_CLOSING;
 331                                 return ret;
 332                         }
 333
 334                         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
 335                         return len;
 336                 }
 337                 break;
 338
 339         case FFS_ACTIVE:
 340                 data = NULL;
 341                 /*
 342                  * We're called from user space, we can use _irq
 343                  * rather then _irqsave
 344                  */
 345                 spin_lock_irq(&ffs->ev.waitq.lock);
 346                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 347                 case FFS_SETUP_CANCELLED:
 348                         ret = -EIDRM;
 349                         goto done_spin;
 350
 351                 case FFS_NO_SETUP:
 352                         ret = -ESRCH;
 353                         goto done_spin;
 354
 355                 case FFS_SETUP_PENDING:
 356                         break;
 357                 }
 358
 359                 /* FFS_SETUP_PENDING */
 360                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 361                         spin_unlock_irq(&ffs->ev.waitq.lock);
 362                         ret = __ffs_ep0_stall(ffs);
 363                         break;
 364                 }
 365
 366                 /* FFS_SETUP_PENDING and not stall */
 367                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 368
 369                 spin_unlock_irq(&ffs->ev.waitq.lock);
 370
 371                 data = ffs_prepare_buffer(buf, len);
 372                 if (IS_ERR(data)) {
 373                         ret = PTR_ERR(data);
 374                         break;
 375                 }
 376
 377                 spin_lock_irq(&ffs->ev.waitq.lock);
 378
 379                 /*
 380                  * We are guaranteed to be still in FFS_ACTIVE state
 381                  * but the state of setup could have changed from
 382                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 383                  * to check for that.  If that happened we copied data
 384                  * from user space in vain but it's unlikely.
 385                  *
 386                  * For sure we are not in FFS_NO_SETUP since this is
 387                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 388                  * transition can be performed and it's protected by
 389                  * mutex.
 390                  */
 391                 if (ffs_setup_state_clear_cancelled(ffs) ==
 392                     FFS_SETUP_CANCELLED) {
 393                         ret = -EIDRM;
 394 done_spin:
 395                         spin_unlock_irq(&ffs->ev.waitq.lock);
 396                 } else {
 397                         /* unlocks spinlock */
 398                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 399                 }
 400                 kfree(data);
 401                 break;
 402
 403         default:
 404                 ret = -EBADFD;
 405                 break;
 406         }
 407
 408         mutex_unlock(&ffs->mutex);
 409         return ret;
 410 }
 411
 412 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 413                                      size_t n)
 414 {
 415         /*
 416          * We are holding ffs->ev.waitq.lock and ffs->mutex and we need
 417          * to release them.
 418          */
 419         struct usb_functionfs_event events[n];
 420         unsigned i = 0;
 421
 422         memset(events, 0, sizeof events);
 423
 424         do {
 425                 events[i].type = ffs->ev.types[i];
 426                 if (events[i].type == FUNCTIONFS_SETUP) {
 427                         events[i].u.setup = ffs->ev.setup;
 428                         ffs->setup_state = FFS_SETUP_PENDING;
 429                 }
 430         } while (++i < n);
 431
 432         if (n < ffs->ev.count) {
 433                 ffs->ev.count -= n;
 434                 memmove(ffs->ev.types, ffs->ev.types + n,
 435                         ffs->ev.count * sizeof *ffs->ev.types);
 436         } else {
 437                 ffs->ev.count = 0;
 438         }
 439
 440         spin_unlock_irq(&ffs->ev.waitq.lock);
 441         mutex_unlock(&ffs->mutex);
 442
 443         return unlikely(__copy_to_user(buf, events, sizeof events))
 444                 ? -EFAULT : sizeof events;
 445 }
 446
 447 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 448                             size_t len, loff_t *ptr)
 449 {
 450         struct ffs_data *ffs = file->private_data;
 451         char *data = NULL;
 452         size_t n;
 453         int ret;
 454
 455         ENTER();
 456
 457         /* Fast check if setup was canceled */
 458         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 459                 return -EIDRM;
 460
 461         /* Acquire mutex */
 462         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 463         if (unlikely(ret < 0))
 464                 return ret;
 465
 466         /* Check state */
 467         if (ffs->state != FFS_ACTIVE) {
 468                 ret = -EBADFD;
 469                 goto done_mutex;
 470         }
 471
 472         /*
 473          * We're called from user space, we can use _irq rather then
 474          * _irqsave
 475          */
 476         spin_lock_irq(&ffs->ev.waitq.lock);
 477
 478         switch (ffs_setup_state_clear_cancelled(ffs)) {
 479         case FFS_SETUP_CANCELLED:
 480                 ret = -EIDRM;
 481                 break;
 482
 483         case FFS_NO_SETUP:
 484                 n = len / sizeof(struct usb_functionfs_event);
 485                 if (unlikely(!n)) {
 486                         ret = -EINVAL;
 487                         break;
 488                 }
 489
 490                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 491                         ret = -EAGAIN;
 492                         break;
 493                 }
 494
 495                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 496                                                         ffs->ev.count)) {
 497                         ret = -EINTR;
 498                         break;
 499                 }
 500
 501                 return __ffs_ep0_read_events(ffs, buf,
 502                                              min(n, (size_t)ffs->ev.count));
 503
 504         case FFS_SETUP_PENDING:
 505                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 506                         spin_unlock_irq(&ffs->ev.waitq.lock);
 507                         ret = __ffs_ep0_stall(ffs);
 508                         goto done_mutex;
 509                 }
 510
 511                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 512
 513                 spin_unlock_irq(&ffs->ev.waitq.lock);
 514
 515                 if (likely(len)) {
 516                         data = kmalloc(len, GFP_KERNEL);
 517                         if (unlikely(!data)) {
 518                                 ret = -ENOMEM;
 519                                 goto done_mutex;
 520                         }
 521                 }
 522
 523                 spin_lock_irq(&ffs->ev.waitq.lock);
 524
 525                 /* See ffs_ep0_write() */
 526                 if (ffs_setup_state_clear_cancelled(ffs) ==
 527                     FFS_SETUP_CANCELLED) {
 528                         ret = -EIDRM;
 529                         break;
 530                 }
 531
 532                 /* unlocks spinlock */
 533                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 534                 if (likely(ret > 0) && unlikely(__copy_to_user(buf, data, len)))
 535                         ret = -EFAULT;
 536                 goto done_mutex;
 537
 538         default:
 539                 ret = -EBADFD;
 540                 break;
 541         }
 542
 543         spin_unlock_irq(&ffs->ev.waitq.lock);
 544 done_mutex:
 545         mutex_unlock(&ffs->mutex);
 546         kfree(data);
 547         return ret;
 548 }
 549
 550 static int ffs_ep0_open(struct inode *inode, struct file *file)
 551 {
 552         struct ffs_data *ffs = inode->i_private;
 553
 554         ENTER();
 555
 556         if (unlikely(ffs->state == FFS_CLOSING))
 557                 return -EBUSY;
 558
 559         file->private_data = ffs;
 560         ffs_data_opened(ffs);
 561
 562         return 0;
 563 }
 564
 565 static int ffs_ep0_release(struct inode *inode, struct file *file)
 566 {
 567         struct ffs_data *ffs = file->private_data;
 568
 569         ENTER();
 570
 571         ffs_data_closed(ffs);
 572
 573         return 0;
 574 }
 575
 576 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 577 {
 578         struct ffs_data *ffs = file->private_data;
 579         struct usb_gadget *gadget = ffs->gadget;
 580         long ret;
 581
 582         ENTER();
 583
 584         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 585                 struct ffs_function *func = ffs->func;
 586                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 587         } else if (gadget && gadget->ops->ioctl) {
 588                 ret = gadget->ops->ioctl(gadget, code, value);
 589         } else {
 590                 ret = -ENOTTY;
 591         }
 592
 593         return ret;
 594 }
 595
 596 static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
 597 {
 598         struct ffs_data *ffs = file->private_data;
 599         unsigned int mask = POLLWRNORM;
 600         int ret;
 601
 602         poll_wait(file, &ffs->ev.waitq, wait);
 603
 604         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 605         if (unlikely(ret < 0))
 606                 return mask;
 607
 608         switch (ffs->state) {
 609         case FFS_READ_DESCRIPTORS:
 610         case FFS_READ_STRINGS:
 611                 mask |= POLLOUT;
 612                 break;
 613
 614         case FFS_ACTIVE:
 615                 switch (ffs->setup_state) {
 616                 case FFS_NO_SETUP:
 617                         if (ffs->ev.count)
 618                                 mask |= POLLIN;
 619                         break;
 620
 621                 case FFS_SETUP_PENDING:
 622                 case FFS_SETUP_CANCELLED:
 623                         mask |= (POLLIN | POLLOUT);
 624                         break;
 625                 }
 626         case FFS_CLOSING:
 627                 break;
 628         }
 629
 630         mutex_unlock(&ffs->mutex);
 631
 632         return mask;
 633 }
 634
 635 static const struct file_operations ffs_ep0_operations = {
 636         .llseek =       no_llseek,
 637
 638         .open =         ffs_ep0_open,
 639         .write =        ffs_ep0_write,
 640         .read =         ffs_ep0_read,
 641         .release =      ffs_ep0_release,
 642         .unlocked_ioctl =       ffs_ep0_ioctl,
 643         .poll =         ffs_ep0_poll,
 644 };
 645
 646
 647 /* "Normal" endpoints operations ********************************************/
 648
 649 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 650 {
 651         ENTER();
 652         if (likely(req->context)) {
 653                 struct ffs_ep *ep = _ep->driver_data;
 654                 ep->status = req->status ? req->status : req->actual;
 655                 complete(req->context);
 656         }
 657 }
 658
 659 static void ffs_user_copy_worker(struct work_struct *work)
 660 {
 661         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 662                                                    work);
 663         int ret = io_data->req->status ? io_data->req->status :
 664                                          io_data->req->actual;
 665
 666         if (io_data->read && ret > 0) {
 667                 int i;
 668                 size_t pos = 0;
 669                 use_mm(io_data->mm);
 670                 for (i = 0; i < io_data->nr_segs; i++) {
 671                         if (unlikely(copy_to_user(io_data->iovec[i].iov_base,
 672                                                  &io_data->buf[pos],
 673                                                  io_data->iovec[i].iov_len))) {
 674                                 ret = -EFAULT;
 675                                 break;
 676                         }
 677                         pos += io_data->iovec[i].iov_len;
 678                 }
 679                 unuse_mm(io_data->mm);
 680         }
 681
 682         aio_complete(io_data->kiocb, ret, ret);
 683
 684         usb_ep_free_request(io_data->ep, io_data->req);
 685
 686         io_data->kiocb->private = NULL;
 687         if (io_data->read)
 688                 kfree(io_data->iovec);
 689         kfree(io_data->buf);
 690         kfree(io_data);
 691 }
 692
 693 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 694                                          struct usb_request *req)
 695 {
 696         struct ffs_io_data *io_data = req->context;
 697
 698         ENTER();
 699
 700         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 701         schedule_work(&io_data->work);
 702 }
 703
 704 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 705 {
 706         struct ffs_epfile *epfile = file->private_data;
 707         struct ffs_ep *ep;
 708         char *data = NULL;
 709         ssize_t ret, data_len;
 710         int halt;
 711
 712         /* Are we still active? */
 713         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
 714                 ret = -ENODEV;
 715                 goto error;
 716         }
 717
 718         /* Wait for endpoint to be enabled */
 719         ep = epfile->ep;
 720         if (!ep) {
 721                 if (file->f_flags & O_NONBLOCK) {
 722                         ret = -EAGAIN;
 723                         goto error;
 724                 }
 725
 726                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
 727                 if (ret) {
 728                         ret = -EINTR;
 729                         goto error;
 730                 }
 731         }
 732
 733         /* Do we halt? */
 734         halt = (!io_data->read == !epfile->in);
 735         if (halt && epfile->isoc) {
 736                 ret = -EINVAL;
 737                 goto error;
 738         }
 739
 740         /* Allocate & copy */
 741         if (!halt) {
 742                 /*
 743                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 744                  * before the waiting completes, so do not assign to 'gadget' earlier
 745                  */
 746                 struct usb_gadget *gadget = epfile->ffs->gadget;
 747
 748                 /*
 749                  * Controller may require buffer size to be aligned to
 750                  * maxpacketsize of an out endpoint.
 751                  */
 752                 data_len = io_data->read ?
 753                            usb_ep_align_maybe(gadget, ep->ep, io_data->len) :
 754                            io_data->len;
 755
 756                 data = kmalloc(data_len, GFP_KERNEL);
 757                 if (unlikely(!data))
 758                         return -ENOMEM;
 759                 if (io_data->aio && !io_data->read) {
 760                         int i;
 761                         size_t pos = 0;
 762                         for (i = 0; i < io_data->nr_segs; i++) {
 763                                 if (unlikely(copy_from_user(&data[pos],
 764                                              io_data->iovec[i].iov_base,
 765                                              io_data->iovec[i].iov_len))) {
 766                                         ret = -EFAULT;
 767                                         goto error;
 768                                 }
 769                                 pos += io_data->iovec[i].iov_len;
 770                         }
 771                 } else {
 772                         if (!io_data->read &&
 773                             unlikely(__copy_from_user(data, io_data->buf,
 774                                                       io_data->len))) {
 775                                 ret = -EFAULT;
 776                                 goto error;
 777                         }
 778                 }
 779         }
 780
 781         /* We will be using request */
 782         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 783         if (unlikely(ret))
 784                 goto error;
 785
 786         spin_lock_irq(&epfile->ffs->eps_lock);
 787
 788         if (epfile->ep != ep) {
 789                 /* In the meantime, endpoint got disabled or changed. */
 790                 ret = -ESHUTDOWN;
 791                 spin_unlock_irq(&epfile->ffs->eps_lock);
 792         } else if (halt) {
 793                 /* Halt */
 794                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 795                         usb_ep_set_halt(ep->ep);
 796                 spin_unlock_irq(&epfile->ffs->eps_lock);
 797                 ret = -EBADMSG;
 798         } else {
 799                 /* Fire the request */
 800                 struct usb_request *req;
 801
 802                 if (io_data->aio) {
 803                         req = usb_ep_alloc_request(ep->ep, GFP_KERNEL);
 804                         if (unlikely(!req))
 805                                 goto error_lock;
 806
 807                         req->buf      = data;
 808                         req->length   = io_data->len;
 809
 810                         io_data->buf = data;
 811                         io_data->ep = ep->ep;
 812                         io_data->req = req;
 813
 814                         req->context  = io_data;
 815                         req->complete = ffs_epfile_async_io_complete;
 816
 817                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 818                         if (unlikely(ret)) {
 819                                 usb_ep_free_request(ep->ep, req);
 820                                 goto error_lock;
 821                         }
 822                         ret = -EIOCBQUEUED;
 823
 824                         spin_unlock_irq(&epfile->ffs->eps_lock);
 825                 } else {
 826                         DECLARE_COMPLETION_ONSTACK(done);
 827
 828                         req = ep->req;
 829                         req->buf      = data;
 830                         req->length   = io_data->len;
 831
 832                         req->context  = &done;
 833                         req->complete = ffs_epfile_io_complete;
 834
 835                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 836
 837                         spin_unlock_irq(&epfile->ffs->eps_lock);
 838
 839                         if (unlikely(ret < 0)) {
 840                                 /* nop */
 841                         } else if (unlikely(
 842                                    wait_for_completion_interruptible(&done))) {
 843                                 ret = -EINTR;
 844                                 usb_ep_dequeue(ep->ep, req);
 845                         } else {
 846                                 /*
 847                                  * XXX We may end up silently droping data
 848                                  * here.  Since data_len (i.e. req->length) may
 849                                  * be bigger than len (after being rounded up
 850                                  * to maxpacketsize), we may end up with more
 851                                  * data then user space has space for.
 852                                  */
 853                                 ret = ep->status;
 854                                 if (io_data->read && ret > 0) {
 855                                         ret = min_t(size_t, ret, io_data->len);
 856
 857                                         if (unlikely(copy_to_user(io_data->buf,
 858                                                 data, ret)))
 859                                                 ret = -EFAULT;
 860                                 }
 861                         }
 862                         kfree(data);
 863                 }
 864         }
 865
 866         mutex_unlock(&epfile->mutex);
 867         return ret;
 868
 869 error_lock:
 870         spin_unlock_irq(&epfile->ffs->eps_lock);
 871         mutex_unlock(&epfile->mutex);
 872 error:
 873         kfree(data);
 874         return ret;
 875 }
 876
 877 static ssize_t
 878 ffs_epfile_write(struct file *file, const char __user *buf, size_t len,
 879                  loff_t *ptr)
 880 {
 881         struct ffs_io_data io_data;
 882
 883         ENTER();
 884
 885         io_data.aio = false;
 886         io_data.read = false;
 887         io_data.buf = (char * __user)buf;
 888         io_data.len = len;
 889
 890         return ffs_epfile_io(file, &io_data);
 891 }
 892
 893 static ssize_t
 894 ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr)
 895 {
 896         struct ffs_io_data io_data;
 897
 898         ENTER();
 899
 900         io_data.aio = false;
 901         io_data.read = true;
 902         io_data.buf = buf;
 903         io_data.len = len;
 904
 905         return ffs_epfile_io(file, &io_data);
 906 }
 907
 908 static int
 909 ffs_epfile_open(struct inode *inode, struct file *file)
 910 {
 911         struct ffs_epfile *epfile = inode->i_private;
 912
 913         ENTER();
 914
 915         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 916                 return -ENODEV;
 917
 918         file->private_data = epfile;
 919         ffs_data_opened(epfile->ffs);
 920
 921         return 0;
 922 }
 923
 924 static int ffs_aio_cancel(struct kiocb *kiocb)
 925 {
 926         struct ffs_io_data *io_data = kiocb->private;
 927         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
 928         int value;
 929
 930         ENTER();
 931
 932         spin_lock_irq(&epfile->ffs->eps_lock);
 933
 934         if (likely(io_data && io_data->ep && io_data->req))
 935                 value = usb_ep_dequeue(io_data->ep, io_data->req);
 936         else
 937                 value = -EINVAL;
 938
 939         spin_unlock_irq(&epfile->ffs->eps_lock);
 940
 941         return value;
 942 }
 943
 944 static ssize_t ffs_epfile_aio_write(struct kiocb *kiocb,
 945                                     const struct iovec *iovec,
 946                                     unsigned long nr_segs, loff_t loff)
 947 {
 948         struct ffs_io_data *io_data;
 949
 950         ENTER();
 951
 952         io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
 953         if (unlikely(!io_data))
 954                 return -ENOMEM;
 955
 956         io_data->aio = true;
 957         io_data->read = false;
 958         io_data->kiocb = kiocb;
 959         io_data->iovec = iovec;
 960         io_data->nr_segs = nr_segs;
 961         io_data->len = kiocb->ki_nbytes;
 962         io_data->mm = current->mm;
 963
 964         kiocb->private = io_data;
 965
 966         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 967
 968         return ffs_epfile_io(kiocb->ki_filp, io_data);
 969 }
 970
 971 static ssize_t ffs_epfile_aio_read(struct kiocb *kiocb,
 972                                    const struct iovec *iovec,
 973                                    unsigned long nr_segs, loff_t loff)
 974 {
 975         struct ffs_io_data *io_data;
 976         struct iovec *iovec_copy;
 977
 978         ENTER();
 979
 980         iovec_copy = kmalloc_array(nr_segs, sizeof(*iovec_copy), GFP_KERNEL);
 981         if (unlikely(!iovec_copy))
 982                 return -ENOMEM;
 983
 984         memcpy(iovec_copy, iovec, sizeof(struct iovec)*nr_segs);
 985
 986         io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
 987         if (unlikely(!io_data)) {
 988                 kfree(iovec_copy);
 989                 return -ENOMEM;
 990         }
 991
 992         io_data->aio = true;
 993         io_data->read = true;
 994         io_data->kiocb = kiocb;
 995         io_data->iovec = iovec_copy;
 996         io_data->nr_segs = nr_segs;
 997         io_data->len = kiocb->ki_nbytes;
 998         io_data->mm = current->mm;
 999
1000         kiocb->private = io_data;
1001
1002         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1003
1004         return ffs_epfile_io(kiocb->ki_filp, io_data);
1005 }
1006
1007 static int
1008 ffs_epfile_release(struct inode *inode, struct file *file)
1009 {
1010         struct ffs_epfile *epfile = inode->i_private;
1011
1012         ENTER();
1013
1014         ffs_data_closed(epfile->ffs);
1015
1016         return 0;
1017 }
1018
1019 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1020                              unsigned long value)
1021 {
1022         struct ffs_epfile *epfile = file->private_data;
1023         int ret;
1024
1025         ENTER();
1026
1027         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1028                 return -ENODEV;
1029
1030         spin_lock_irq(&epfile->ffs->eps_lock);
1031         if (likely(epfile->ep)) {
1032                 switch (code) {
1033                 case FUNCTIONFS_FIFO_STATUS:
1034                         ret = usb_ep_fifo_status(epfile->ep->ep);
1035                         break;
1036                 case FUNCTIONFS_FIFO_FLUSH:
1037                         usb_ep_fifo_flush(epfile->ep->ep);
1038                         ret = 0;
1039                         break;
1040                 case FUNCTIONFS_CLEAR_HALT:
1041                         ret = usb_ep_clear_halt(epfile->ep->ep);
1042                         break;
1043                 case FUNCTIONFS_ENDPOINT_REVMAP:
1044                         ret = epfile->ep->num;
1045                         break;
1046                 default:
1047                         ret = -ENOTTY;
1048                 }
1049         } else {
1050                 ret = -ENODEV;
1051         }
1052         spin_unlock_irq(&epfile->ffs->eps_lock);
1053
1054         return ret;
1055 }
1056
1057 static const struct file_operations ffs_epfile_operations = {
1058         .llseek =       no_llseek,
1059
1060         .open =         ffs_epfile_open,
1061         .write =        ffs_epfile_write,
1062         .read =         ffs_epfile_read,
1063         .aio_write =    ffs_epfile_aio_write,
1064         .aio_read =     ffs_epfile_aio_read,
1065         .release =      ffs_epfile_release,
1066         .unlocked_ioctl =       ffs_epfile_ioctl,
1067 };
1068
1069
1070 /* File system and super block operations ***********************************/
1071
1072 /*
1073  * Mounting the file system creates a controller file, used first for
1074  * function configuration then later for event monitoring.
1075  */
1076
1077 static struct inode *__must_check
1078 ffs_sb_make_inode(struct super_block *sb, void *data,
1079                   const struct file_operations *fops,
1080                   const struct inode_operations *iops,
1081                   struct ffs_file_perms *perms)
1082 {
1083         struct inode *inode;
1084
1085         ENTER();
1086
1087         inode = new_inode(sb);
1088
1089         if (likely(inode)) {
1090                 struct timespec current_time = CURRENT_TIME;
1091
1092                 inode->i_ino     = get_next_ino();
1093                 inode->i_mode    = perms->mode;
1094                 inode->i_uid     = perms->uid;
1095                 inode->i_gid     = perms->gid;
1096                 inode->i_atime   = current_time;
1097                 inode->i_mtime   = current_time;
1098                 inode->i_ctime   = current_time;
1099                 inode->i_private = data;
1100                 if (fops)
1101                         inode->i_fop = fops;
1102                 if (iops)
1103                         inode->i_op  = iops;
1104         }
1105
1106         return inode;
1107 }
1108
1109 /* Create "regular" file */
1110 static struct inode *ffs_sb_create_file(struct super_block *sb,
1111                                         const char *name, void *data,
1112                                         const struct file_operations *fops,
1113                                         struct dentry **dentry_p)
1114 {
1115         struct ffs_data *ffs = sb->s_fs_info;
1116         struct dentry   *dentry;
1117         struct inode    *inode;
1118
1119         ENTER();
1120
1121         dentry = d_alloc_name(sb->s_root, name);
1122         if (unlikely(!dentry))
1123                 return NULL;
1124
1125         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1126         if (unlikely(!inode)) {
1127                 dput(dentry);
1128                 return NULL;
1129         }
1130
1131         d_add(dentry, inode);
1132         if (dentry_p)
1133                 *dentry_p = dentry;
1134
1135         return inode;
1136 }
1137
1138 /* Super block */
1139 static const struct super_operations ffs_sb_operations = {
1140         .statfs =       simple_statfs,
1141         .drop_inode =   generic_delete_inode,
1142 };
1143
1144 struct ffs_sb_fill_data {
1145         struct ffs_file_perms perms;
1146         umode_t root_mode;
1147         const char *dev_name;
1148         struct ffs_data *ffs_data;
1149 };
1150
1151 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1152 {
1153         struct ffs_sb_fill_data *data = _data;
1154         struct inode    *inode;
1155         struct ffs_data *ffs = data->ffs_data;
1156
1157         ENTER();
1158
1159         ffs->sb              = sb;
1160         data->ffs_data       = NULL;
1161         sb->s_fs_info        = ffs;
1162         sb->s_blocksize      = PAGE_CACHE_SIZE;
1163         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1164         sb->s_magic          = FUNCTIONFS_MAGIC;
1165         sb->s_op             = &ffs_sb_operations;
1166         sb->s_time_gran      = 1;
1167
1168         /* Root inode */
1169         data->perms.mode = data->root_mode;
1170         inode = ffs_sb_make_inode(sb, NULL,
1171                                   &simple_dir_operations,
1172                                   &simple_dir_inode_operations,
1173                                   &data->perms);
1174         sb->s_root = d_make_root(inode);
1175         if (unlikely(!sb->s_root))
1176                 return -ENOMEM;
1177
1178         /* EP0 file */
1179         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1180                                          &ffs_ep0_operations, NULL)))
1181                 return -ENOMEM;
1182
1183         return 0;
1184 }
1185
1186 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1187 {
1188         ENTER();
1189
1190         if (!opts || !*opts)
1191                 return 0;
1192
1193         for (;;) {
1194                 unsigned long value;
1195                 char *eq, *comma;
1196
1197                 /* Option limit */
1198                 comma = strchr(opts, ',');
1199                 if (comma)
1200                         *comma = 0;
1201
1202                 /* Value limit */
1203                 eq = strchr(opts, '=');
1204                 if (unlikely(!eq)) {
1205                         pr_err("'=' missing in %s\n", opts);
1206                         return -EINVAL;
1207                 }
1208                 *eq = 0;
1209
1210                 /* Parse value */
1211                 if (kstrtoul(eq + 1, 0, &value)) {
1212                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1213                         return -EINVAL;
1214                 }
1215
1216                 /* Interpret option */
1217                 switch (eq - opts) {
1218                 case 5:
1219                         if (!memcmp(opts, "rmode", 5))
1220                                 data->root_mode  = (value & 0555) | S_IFDIR;
1221                         else if (!memcmp(opts, "fmode", 5))
1222                                 data->perms.mode = (value & 0666) | S_IFREG;
1223                         else
1224                                 goto invalid;
1225                         break;
1226
1227                 case 4:
1228                         if (!memcmp(opts, "mode", 4)) {
1229                                 data->root_mode  = (value & 0555) | S_IFDIR;
1230                                 data->perms.mode = (value & 0666) | S_IFREG;
1231                         } else {
1232                                 goto invalid;
1233                         }
1234                         break;
1235
1236                 case 3:
1237                         if (!memcmp(opts, "uid", 3)) {
1238                                 data->perms.uid = make_kuid(current_user_ns(), value);
1239                                 if (!uid_valid(data->perms.uid)) {
1240                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1241                                         return -EINVAL;
1242                                 }
1243                         } else if (!memcmp(opts, "gid", 3)) {
1244                                 data->perms.gid = make_kgid(current_user_ns(), value);
1245                                 if (!gid_valid(data->perms.gid)) {
1246                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1247                                         return -EINVAL;
1248                                 }
1249                         } else {
1250                                 goto invalid;
1251                         }
1252                         break;
1253
1254                 default:
1255 invalid:
1256                         pr_err("%s: invalid option\n", opts);
1257                         return -EINVAL;
1258                 }
1259
1260                 /* Next iteration */
1261                 if (!comma)
1262                         break;
1263                 opts = comma + 1;
1264         }
1265
1266         return 0;
1267 }
1268
1269 /* "mount -t functionfs dev_name /dev/function" ends up here */
1270
1271 static struct dentry *
1272 ffs_fs_mount(struct file_system_type *t, int flags,
1273               const char *dev_name, void *opts)
1274 {
1275         struct ffs_sb_fill_data data = {
1276                 .perms = {
1277                         .mode = S_IFREG | 0600,
1278                         .uid = GLOBAL_ROOT_UID,
1279                         .gid = GLOBAL_ROOT_GID,
1280                 },
1281                 .root_mode = S_IFDIR | 0500,
1282         };
1283         struct dentry *rv;
1284         int ret;
1285         void *ffs_dev;
1286         struct ffs_data *ffs;
1287
1288         ENTER();
1289
1290         ret = ffs_fs_parse_opts(&data, opts);
1291         if (unlikely(ret < 0))
1292                 return ERR_PTR(ret);
1293
1294         ffs = ffs_data_new();
1295         if (unlikely(!ffs))
1296                 return ERR_PTR(-ENOMEM);
1297         ffs->file_perms = data.perms;
1298
1299         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1300         if (unlikely(!ffs->dev_name)) {
1301                 ffs_data_put(ffs);
1302                 return ERR_PTR(-ENOMEM);
1303         }
1304
1305         ffs_dev = ffs_acquire_dev(dev_name);
1306         if (IS_ERR(ffs_dev)) {
1307                 ffs_data_put(ffs);
1308                 return ERR_CAST(ffs_dev);
1309         }
1310         ffs->private_data = ffs_dev;
1311         data.ffs_data = ffs;
1312
1313         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1314         if (IS_ERR(rv) && data.ffs_data) {
1315                 ffs_release_dev(data.ffs_data);
1316                 ffs_data_put(data.ffs_data);
1317         }
1318         return rv;
1319 }
1320
1321 static void
1322 ffs_fs_kill_sb(struct super_block *sb)
1323 {
1324         ENTER();
1325
1326         kill_litter_super(sb);
1327         if (sb->s_fs_info) {
1328                 ffs_release_dev(sb->s_fs_info);
1329                 ffs_data_put(sb->s_fs_info);
1330         }
1331 }
1332
1333 static struct file_system_type ffs_fs_type = {
1334         .owner          = THIS_MODULE,
1335         .name           = "functionfs",
1336         .mount          = ffs_fs_mount,
1337         .kill_sb        = ffs_fs_kill_sb,
1338 };
1339 MODULE_ALIAS_FS("functionfs");
1340
1341
1342 /* Driver's main init/cleanup functions *************************************/
1343
1344 static int functionfs_init(void)
1345 {
1346         int ret;
1347
1348         ENTER();
1349
1350         ret = register_filesystem(&ffs_fs_type);
1351         if (likely(!ret))
1352                 pr_info("file system registered\n");
1353         else
1354                 pr_err("failed registering file system (%d)\n", ret);
1355
1356         return ret;
1357 }
1358
1359 static void functionfs_cleanup(void)
1360 {
1361         ENTER();
1362
1363         pr_info("unloading\n");
1364         unregister_filesystem(&ffs_fs_type);
1365 }
1366
1367
1368 /* ffs_data and ffs_function construction and destruction code **************/
1369
1370 static void ffs_data_clear(struct ffs_data *ffs);
1371 static void ffs_data_reset(struct ffs_data *ffs);
1372
1373 static void ffs_data_get(struct ffs_data *ffs)
1374 {
1375         ENTER();
1376
1377         atomic_inc(&ffs->ref);
1378 }
1379
1380 static void ffs_data_opened(struct ffs_data *ffs)
1381 {
1382         ENTER();
1383
1384         atomic_inc(&ffs->ref);
1385         atomic_inc(&ffs->opened);
1386 }
1387
1388 static void ffs_data_put(struct ffs_data *ffs)
1389 {
1390         ENTER();
1391
1392         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1393                 pr_info("%s(): freeing\n", __func__);
1394                 ffs_data_clear(ffs);
1395                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1396                        waitqueue_active(&ffs->ep0req_completion.wait));
1397                 kfree(ffs->dev_name);
1398                 kfree(ffs);
1399         }
1400 }
1401
1402 static void ffs_data_closed(struct ffs_data *ffs)
1403 {
1404         ENTER();
1405
1406         if (atomic_dec_and_test(&ffs->opened)) {
1407                 ffs->state = FFS_CLOSING;
1408                 ffs_data_reset(ffs);
1409         }
1410
1411         ffs_data_put(ffs);
1412 }
1413
1414 static struct ffs_data *ffs_data_new(void)
1415 {
1416         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1417         if (unlikely(!ffs))
1418                 return NULL;
1419
1420         ENTER();
1421
1422         atomic_set(&ffs->ref, 1);
1423         atomic_set(&ffs->opened, 0);
1424         ffs->state = FFS_READ_DESCRIPTORS;
1425         mutex_init(&ffs->mutex);
1426         spin_lock_init(&ffs->eps_lock);
1427         init_waitqueue_head(&ffs->ev.waitq);
1428         init_completion(&ffs->ep0req_completion);
1429
1430         /* XXX REVISIT need to update it in some places, or do we? */
1431         ffs->ev.can_stall = 1;
1432
1433         return ffs;
1434 }
1435
1436 static void ffs_data_clear(struct ffs_data *ffs)
1437 {
1438         ENTER();
1439
1440         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags))
1441                 ffs_closed(ffs);
1442
1443         BUG_ON(ffs->gadget);
1444
1445         if (ffs->epfiles)
1446                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1447
1448         kfree(ffs->raw_descs_data);
1449         kfree(ffs->raw_strings);
1450         kfree(ffs->stringtabs);
1451 }
1452
1453 static void ffs_data_reset(struct ffs_data *ffs)
1454 {
1455         ENTER();
1456
1457         ffs_data_clear(ffs);
1458
1459         ffs->epfiles = NULL;
1460         ffs->raw_descs_data = NULL;
1461         ffs->raw_descs = NULL;
1462         ffs->raw_strings = NULL;
1463         ffs->stringtabs = NULL;
1464
1465         ffs->raw_descs_length = 0;
1466         ffs->fs_descs_count = 0;
1467         ffs->hs_descs_count = 0;
1468         ffs->ss_descs_count = 0;
1469
1470         ffs->strings_count = 0;
1471         ffs->interfaces_count = 0;
1472         ffs->eps_count = 0;
1473
1474         ffs->ev.count = 0;
1475
1476         ffs->state = FFS_READ_DESCRIPTORS;
1477         ffs->setup_state = FFS_NO_SETUP;
1478         ffs->flags = 0;
1479 }
1480
1481
1482 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1483 {
1484         struct usb_gadget_strings **lang;
1485         int first_id;
1486
1487         ENTER();
1488
1489         if (WARN_ON(ffs->state != FFS_ACTIVE
1490                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1491                 return -EBADFD;
1492
1493         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1494         if (unlikely(first_id < 0))
1495                 return first_id;
1496
1497         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1498         if (unlikely(!ffs->ep0req))
1499                 return -ENOMEM;
1500         ffs->ep0req->complete = ffs_ep0_complete;
1501         ffs->ep0req->context = ffs;
1502
1503         lang = ffs->stringtabs;
1504         for (lang = ffs->stringtabs; *lang; ++lang) {
1505                 struct usb_string *str = (*lang)->strings;
1506                 int id = first_id;
1507                 for (; str->s; ++id, ++str)
1508                         str->id = id;
1509         }
1510
1511         ffs->gadget = cdev->gadget;
1512         ffs_data_get(ffs);
1513         return 0;
1514 }
1515
1516 static void functionfs_unbind(struct ffs_data *ffs)
1517 {
1518         ENTER();
1519
1520         if (!WARN_ON(!ffs->gadget)) {
1521                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1522                 ffs->ep0req = NULL;
1523                 ffs->gadget = NULL;
1524                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1525                 ffs_data_put(ffs);
1526         }
1527 }
1528
1529 static int ffs_epfiles_create(struct ffs_data *ffs)
1530 {
1531         struct ffs_epfile *epfile, *epfiles;
1532         unsigned i, count;
1533
1534         ENTER();
1535
1536         count = ffs->eps_count;
1537         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1538         if (!epfiles)
1539                 return -ENOMEM;
1540
1541         epfile = epfiles;
1542         for (i = 1; i <= count; ++i, ++epfile) {
1543                 epfile->ffs = ffs;
1544                 mutex_init(&epfile->mutex);
1545                 init_waitqueue_head(&epfile->wait);
1546                 sprintf(epfiles->name, "ep%u",  i);
1547                 if (!unlikely(ffs_sb_create_file(ffs->sb, epfiles->name, epfile,
1548                                                  &ffs_epfile_operations,
1549                                                  &epfile->dentry))) {
1550                         ffs_epfiles_destroy(epfiles, i - 1);
1551                         return -ENOMEM;
1552                 }
1553         }
1554
1555         ffs->epfiles = epfiles;
1556         return 0;
1557 }
1558
1559 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1560 {
1561         struct ffs_epfile *epfile = epfiles;
1562
1563         ENTER();
1564
1565         for (; count; --count, ++epfile) {
1566                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1567                        waitqueue_active(&epfile->wait));
1568                 if (epfile->dentry) {
1569                         d_delete(epfile->dentry);
1570                         dput(epfile->dentry);
1571                         epfile->dentry = NULL;
1572                 }
1573         }
1574
1575         kfree(epfiles);
1576 }
1577
1578
1579 static void ffs_func_eps_disable(struct ffs_function *func)
1580 {
1581         struct ffs_ep *ep         = func->eps;
1582         struct ffs_epfile *epfile = func->ffs->epfiles;
1583         unsigned count            = func->ffs->eps_count;
1584         unsigned long flags;
1585
1586         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1587         do {
1588                 /* pending requests get nuked */
1589                 if (likely(ep->ep))
1590                         usb_ep_disable(ep->ep);
1591                 epfile->ep = NULL;
1592
1593                 ++ep;
1594                 ++epfile;
1595         } while (--count);
1596         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1597 }
1598
1599 static int ffs_func_eps_enable(struct ffs_function *func)
1600 {
1601         struct ffs_data *ffs      = func->ffs;
1602         struct ffs_ep *ep         = func->eps;
1603         struct ffs_epfile *epfile = ffs->epfiles;
1604         unsigned count            = ffs->eps_count;
1605         unsigned long flags;
1606         int ret = 0;
1607
1608         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1609         do {
1610                 struct usb_endpoint_descriptor *ds;
1611                 int desc_idx;
1612
1613                 if (ffs->gadget->speed == USB_SPEED_SUPER)
1614                         desc_idx = 2;
1615                 else if (ffs->gadget->speed == USB_SPEED_HIGH)
1616                         desc_idx = 1;
1617                 else
1618                         desc_idx = 0;
1619
1620                 /* fall-back to lower speed if desc missing for current speed */
1621                 do {
1622                         ds = ep->descs[desc_idx];
1623                 } while (!ds && --desc_idx >= 0);
1624
1625                 if (!ds) {
1626                         ret = -EINVAL;
1627                         break;
1628                 }
1629
1630                 ep->ep->driver_data = ep;
1631                 ep->ep->desc = ds;
1632                 ret = usb_ep_enable(ep->ep);
1633                 if (likely(!ret)) {
1634                         epfile->ep = ep;
1635                         epfile->in = usb_endpoint_dir_in(ds);
1636                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1637                 } else {
1638                         break;
1639                 }
1640
1641                 wake_up(&epfile->wait);
1642
1643                 ++ep;
1644                 ++epfile;
1645         } while (--count);
1646         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1647
1648         return ret;
1649 }
1650
1651
1652 /* Parsing and building descriptors and strings *****************************/
1653
1654 /*
1655  * This validates if data pointed by data is a valid USB descriptor as
1656  * well as record how many interfaces, endpoints and strings are
1657  * required by given configuration.  Returns address after the
1658  * descriptor or NULL if data is invalid.
1659  */
1660
1661 enum ffs_entity_type {
1662         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1663 };
1664
1665 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1666                                    u8 *valuep,
1667                                    struct usb_descriptor_header *desc,
1668                                    void *priv);
1669
1670 static int __must_check ffs_do_desc(char *data, unsigned len,
1671                                     ffs_entity_callback entity, void *priv)
1672 {
1673         struct usb_descriptor_header *_ds = (void *)data;
1674         u8 length;
1675         int ret;
1676
1677         ENTER();
1678
1679         /* At least two bytes are required: length and type */
1680         if (len < 2) {
1681                 pr_vdebug("descriptor too short\n");
1682                 return -EINVAL;
1683         }
1684
1685         /* If we have at least as many bytes as the descriptor takes? */
1686         length = _ds->bLength;
1687         if (len < length) {
1688                 pr_vdebug("descriptor longer then available data\n");
1689                 return -EINVAL;
1690         }
1691
1692 #define __entity_check_INTERFACE(val)  1
1693 #define __entity_check_STRING(val)     (val)
1694 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1695 #define __entity(type, val) do {                                        \
1696                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1697                 if (unlikely(!__entity_check_ ##type(val))) {           \
1698                         pr_vdebug("invalid entity's value\n");          \
1699                         return -EINVAL;                                 \
1700                 }                                                       \
1701                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1702                 if (unlikely(ret < 0)) {                                \
1703                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1704                                  (val), ret);                           \
1705                         return ret;                                     \
1706                 }                                                       \
1707         } while (0)
1708
1709         /* Parse descriptor depending on type. */
1710         switch (_ds->bDescriptorType) {
1711         case USB_DT_DEVICE:
1712         case USB_DT_CONFIG:
1713         case USB_DT_STRING:
1714         case USB_DT_DEVICE_QUALIFIER:
1715                 /* function can't have any of those */
1716                 pr_vdebug("descriptor reserved for gadget: %d\n",
1717                       _ds->bDescriptorType);
1718                 return -EINVAL;
1719
1720         case USB_DT_INTERFACE: {
1721                 struct usb_interface_descriptor *ds = (void *)_ds;
1722                 pr_vdebug("interface descriptor\n");
1723                 if (length != sizeof *ds)
1724                         goto inv_length;
1725
1726                 __entity(INTERFACE, ds->bInterfaceNumber);
1727                 if (ds->iInterface)
1728                         __entity(STRING, ds->iInterface);
1729         }
1730                 break;
1731
1732         case USB_DT_ENDPOINT: {
1733                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1734                 pr_vdebug("endpoint descriptor\n");
1735                 if (length != USB_DT_ENDPOINT_SIZE &&
1736                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1737                         goto inv_length;
1738                 __entity(ENDPOINT, ds->bEndpointAddress);
1739         }
1740                 break;
1741
1742         case HID_DT_HID:
1743                 pr_vdebug("hid descriptor\n");
1744                 if (length != sizeof(struct hid_descriptor))
1745                         goto inv_length;
1746                 break;
1747
1748         case USB_DT_OTG:
1749                 if (length != sizeof(struct usb_otg_descriptor))
1750                         goto inv_length;
1751                 break;
1752
1753         case USB_DT_INTERFACE_ASSOCIATION: {
1754                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1755                 pr_vdebug("interface association descriptor\n");
1756                 if (length != sizeof *ds)
1757                         goto inv_length;
1758                 if (ds->iFunction)
1759                         __entity(STRING, ds->iFunction);
1760         }
1761                 break;
1762
1763         case USB_DT_SS_ENDPOINT_COMP:
1764                 pr_vdebug("EP SS companion descriptor\n");
1765                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
1766                         goto inv_length;
1767                 break;
1768
1769         case USB_DT_OTHER_SPEED_CONFIG:
1770         case USB_DT_INTERFACE_POWER:
1771         case USB_DT_DEBUG:
1772         case USB_DT_SECURITY:
1773         case USB_DT_CS_RADIO_CONTROL:
1774                 /* TODO */
1775                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1776                 return -EINVAL;
1777
1778         default:
1779                 /* We should never be here */
1780                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1781                 return -EINVAL;
1782
1783 inv_length:
1784                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1785                           _ds->bLength, _ds->bDescriptorType);
1786                 return -EINVAL;
1787         }
1788
1789 #undef __entity
1790 #undef __entity_check_DESCRIPTOR
1791 #undef __entity_check_INTERFACE
1792 #undef __entity_check_STRING
1793 #undef __entity_check_ENDPOINT
1794
1795         return length;
1796 }
1797
1798 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1799                                      ffs_entity_callback entity, void *priv)
1800 {
1801         const unsigned _len = len;
1802         unsigned long num = 0;
1803
1804         ENTER();
1805
1806         for (;;) {
1807                 int ret;
1808
1809                 if (num == count)
1810                         data = NULL;
1811
1812                 /* Record "descriptor" entity */
1813                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1814                 if (unlikely(ret < 0)) {
1815                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1816                                  num, ret);
1817                         return ret;
1818                 }
1819
1820                 if (!data)
1821                         return _len - len;
1822
1823                 ret = ffs_do_desc(data, len, entity, priv);
1824                 if (unlikely(ret < 0)) {
1825                         pr_debug("%s returns %d\n", __func__, ret);
1826                         return ret;
1827                 }
1828
1829                 len -= ret;
1830                 data += ret;
1831                 ++num;
1832         }
1833 }
1834
1835 static int __ffs_data_do_entity(enum ffs_entity_type type,
1836                                 u8 *valuep, struct usb_descriptor_header *desc,
1837                                 void *priv)
1838 {
1839         struct ffs_data *ffs = priv;
1840
1841         ENTER();
1842
1843         switch (type) {
1844         case FFS_DESCRIPTOR:
1845                 break;
1846
1847         case FFS_INTERFACE:
1848                 /*
1849                  * Interfaces are indexed from zero so if we
1850                  * encountered interface "n" then there are at least
1851                  * "n+1" interfaces.
1852                  */
1853                 if (*valuep >= ffs->interfaces_count)
1854                         ffs->interfaces_count = *valuep + 1;
1855                 break;
1856
1857         case FFS_STRING:
1858                 /*
1859                  * Strings are indexed from 1 (0 is magic ;) reserved
1860                  * for languages list or some such)
1861                  */
1862                 if (*valuep > ffs->strings_count)
1863                         ffs->strings_count = *valuep;
1864                 break;
1865
1866         case FFS_ENDPOINT:
1867                 /* Endpoints are indexed from 1 as well. */
1868                 if ((*valuep & USB_ENDPOINT_NUMBER_MASK) > ffs->eps_count)
1869                         ffs->eps_count = (*valuep & USB_ENDPOINT_NUMBER_MASK);
1870                 break;
1871         }
1872
1873         return 0;
1874 }
1875
1876 static int __ffs_data_got_descs(struct ffs_data *ffs,
1877                                 char *const _data, size_t len)
1878 {
1879         char *data = _data, *raw_descs;
1880         unsigned counts[3], flags;
1881         int ret = -EINVAL, i;
1882
1883         ENTER();
1884
1885         if (get_unaligned_le32(data + 4) != len)
1886                 goto error;
1887
1888         switch (get_unaligned_le32(data)) {
1889         case FUNCTIONFS_DESCRIPTORS_MAGIC:
1890                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
1891                 data += 8;
1892                 len  -= 8;
1893                 break;
1894         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
1895                 flags = get_unaligned_le32(data + 8);
1896                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
1897                               FUNCTIONFS_HAS_HS_DESC |
1898                               FUNCTIONFS_HAS_SS_DESC)) {
1899                         ret = -ENOSYS;
1900                         goto error;
1901                 }
1902                 data += 12;
1903                 len  -= 12;
1904                 break;
1905         default:
1906                 goto error;
1907         }
1908
1909         /* Read fs_count, hs_count and ss_count (if present) */
1910         for (i = 0; i < 3; ++i) {
1911                 if (!(flags & (1 << i))) {
1912                         counts[i] = 0;
1913                 } else if (len < 4) {
1914                         goto error;
1915                 } else {
1916                         counts[i] = get_unaligned_le32(data);
1917                         data += 4;
1918                         len  -= 4;
1919                 }
1920         }
1921
1922         /* Read descriptors */
1923         raw_descs = data;
1924         for (i = 0; i < 3; ++i) {
1925                 if (!counts[i])
1926                         continue;
1927                 ret = ffs_do_descs(counts[i], data, len,
1928                                    __ffs_data_do_entity, ffs);
1929                 if (ret < 0)
1930                         goto error;
1931                 data += ret;
1932                 len  -= ret;
1933         }
1934
1935         if (raw_descs == data || len) {
1936                 ret = -EINVAL;
1937                 goto error;
1938         }
1939
1940         ffs->raw_descs_data     = _data;
1941         ffs->raw_descs          = raw_descs;
1942         ffs->raw_descs_length   = data - raw_descs;
1943         ffs->fs_descs_count     = counts[0];
1944         ffs->hs_descs_count     = counts[1];
1945         ffs->ss_descs_count     = counts[2];
1946
1947         return 0;
1948
1949 error:
1950         kfree(_data);
1951         return ret;
1952 }
1953
1954 static int __ffs_data_got_strings(struct ffs_data *ffs,
1955                                   char *const _data, size_t len)
1956 {
1957         u32 str_count, needed_count, lang_count;
1958         struct usb_gadget_strings **stringtabs, *t;
1959         struct usb_string *strings, *s;
1960         const char *data = _data;
1961
1962         ENTER();
1963
1964         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
1965                      get_unaligned_le32(data + 4) != len))
1966                 goto error;
1967         str_count  = get_unaligned_le32(data + 8);
1968         lang_count = get_unaligned_le32(data + 12);
1969
1970         /* if one is zero the other must be zero */
1971         if (unlikely(!str_count != !lang_count))
1972                 goto error;
1973
1974         /* Do we have at least as many strings as descriptors need? */
1975         needed_count = ffs->strings_count;
1976         if (unlikely(str_count < needed_count))
1977                 goto error;
1978
1979         /*
1980          * If we don't need any strings just return and free all
1981          * memory.
1982          */
1983         if (!needed_count) {
1984                 kfree(_data);
1985                 return 0;
1986         }
1987
1988         /* Allocate everything in one chunk so there's less maintenance. */
1989         {
1990                 unsigned i = 0;
1991                 vla_group(d);
1992                 vla_item(d, struct usb_gadget_strings *, stringtabs,
1993                         lang_count + 1);
1994                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
1995                 vla_item(d, struct usb_string, strings,
1996                         lang_count*(needed_count+1));
1997
1998                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
1999
2000                 if (unlikely(!vlabuf)) {
2001                         kfree(_data);
2002                         return -ENOMEM;
2003                 }
2004
2005                 /* Initialize the VLA pointers */
2006                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2007                 t = vla_ptr(vlabuf, d, stringtab);
2008                 i = lang_count;
2009                 do {
2010                         *stringtabs++ = t++;
2011                 } while (--i);
2012                 *stringtabs = NULL;
2013
2014                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2015                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2016                 t = vla_ptr(vlabuf, d, stringtab);
2017                 s = vla_ptr(vlabuf, d, strings);
2018                 strings = s;
2019         }
2020
2021         /* For each language */
2022         data += 16;
2023         len -= 16;
2024
2025         do { /* lang_count > 0 so we can use do-while */
2026                 unsigned needed = needed_count;
2027
2028                 if (unlikely(len < 3))
2029                         goto error_free;
2030                 t->language = get_unaligned_le16(data);
2031                 t->strings  = s;
2032                 ++t;
2033
2034                 data += 2;
2035                 len -= 2;
2036
2037                 /* For each string */
2038                 do { /* str_count > 0 so we can use do-while */
2039                         size_t length = strnlen(data, len);
2040
2041                         if (unlikely(length == len))
2042                                 goto error_free;
2043
2044                         /*
2045                          * User may provide more strings then we need,
2046                          * if that's the case we simply ignore the
2047                          * rest
2048                          */
2049                         if (likely(needed)) {
2050                                 /*
2051                                  * s->id will be set while adding
2052                                  * function to configuration so for
2053                                  * now just leave garbage here.
2054                                  */
2055                                 s->s = data;
2056                                 --needed;
2057                                 ++s;
2058                         }
2059
2060                         data += length + 1;
2061                         len -= length + 1;
2062                 } while (--str_count);
2063
2064                 s->id = 0;   /* terminator */
2065                 s->s = NULL;
2066                 ++s;
2067
2068         } while (--lang_count);
2069
2070         /* Some garbage left? */
2071         if (unlikely(len))
2072                 goto error_free;
2073
2074         /* Done! */
2075         ffs->stringtabs = stringtabs;
2076         ffs->raw_strings = _data;
2077
2078         return 0;
2079
2080 error_free:
2081         kfree(stringtabs);
2082 error:
2083         kfree(_data);
2084         return -EINVAL;
2085 }
2086
2087
2088 /* Events handling and management *******************************************/
2089
2090 static void __ffs_event_add(struct ffs_data *ffs,
2091                             enum usb_functionfs_event_type type)
2092 {
2093         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2094         int neg = 0;
2095
2096         /*
2097          * Abort any unhandled setup
2098          *
2099          * We do not need to worry about some cmpxchg() changing value
2100          * of ffs->setup_state without holding the lock because when
2101          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2102          * the source does nothing.
2103          */
2104         if (ffs->setup_state == FFS_SETUP_PENDING)
2105                 ffs->setup_state = FFS_SETUP_CANCELLED;
2106
2107         switch (type) {
2108         case FUNCTIONFS_RESUME:
2109                 rem_type2 = FUNCTIONFS_SUSPEND;
2110                 /* FALL THROUGH */
2111         case FUNCTIONFS_SUSPEND:
2112         case FUNCTIONFS_SETUP:
2113                 rem_type1 = type;
2114                 /* Discard all similar events */
2115                 break;
2116
2117         case FUNCTIONFS_BIND:
2118         case FUNCTIONFS_UNBIND:
2119         case FUNCTIONFS_DISABLE:
2120         case FUNCTIONFS_ENABLE:
2121                 /* Discard everything other then power management. */
2122                 rem_type1 = FUNCTIONFS_SUSPEND;
2123                 rem_type2 = FUNCTIONFS_RESUME;
2124                 neg = 1;
2125                 break;
2126
2127         default:
2128                 BUG();
2129         }
2130
2131         {
2132                 u8 *ev  = ffs->ev.types, *out = ev;
2133                 unsigned n = ffs->ev.count;
2134                 for (; n; --n, ++ev)
2135                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2136                                 *out++ = *ev;
2137                         else
2138                                 pr_vdebug("purging event %d\n", *ev);
2139                 ffs->ev.count = out - ffs->ev.types;
2140         }
2141
2142         pr_vdebug("adding event %d\n", type);
2143         ffs->ev.types[ffs->ev.count++] = type;
2144         wake_up_locked(&ffs->ev.waitq);
2145 }
2146
2147 static void ffs_event_add(struct ffs_data *ffs,
2148                           enum usb_functionfs_event_type type)
2149 {
2150         unsigned long flags;
2151         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2152         __ffs_event_add(ffs, type);
2153         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2154 }
2155
2156
2157 /* Bind/unbind USB function hooks *******************************************/
2158
2159 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2160                                     struct usb_descriptor_header *desc,
2161                                     void *priv)
2162 {
2163         struct usb_endpoint_descriptor *ds = (void *)desc;
2164         struct ffs_function *func = priv;
2165         struct ffs_ep *ffs_ep;
2166         unsigned ep_desc_id, idx;
2167         static const char *speed_names[] = { "full", "high", "super" };
2168
2169         if (type != FFS_DESCRIPTOR)
2170                 return 0;
2171
2172         /*
2173          * If ss_descriptors is not NULL, we are reading super speed
2174          * descriptors; if hs_descriptors is not NULL, we are reading high
2175          * speed descriptors; otherwise, we are reading full speed
2176          * descriptors.
2177          */
2178         if (func->function.ss_descriptors) {
2179                 ep_desc_id = 2;
2180                 func->function.ss_descriptors[(long)valuep] = desc;
2181         } else if (func->function.hs_descriptors) {
2182                 ep_desc_id = 1;
2183                 func->function.hs_descriptors[(long)valuep] = desc;
2184         } else {
2185                 ep_desc_id = 0;
2186                 func->function.fs_descriptors[(long)valuep]    = desc;
2187         }
2188
2189         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2190                 return 0;
2191
2192         idx = (ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK) - 1;
2193         ffs_ep = func->eps + idx;
2194
2195         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2196                 pr_err("two %sspeed descriptors for EP %d\n",
2197                           speed_names[ep_desc_id],
2198                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2199                 return -EINVAL;
2200         }
2201         ffs_ep->descs[ep_desc_id] = ds;
2202
2203         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2204         if (ffs_ep->ep) {
2205                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2206                 if (!ds->wMaxPacketSize)
2207                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2208         } else {
2209                 struct usb_request *req;
2210                 struct usb_ep *ep;
2211
2212                 pr_vdebug("autoconfig\n");
2213                 ep = usb_ep_autoconfig(func->gadget, ds);
2214                 if (unlikely(!ep))
2215                         return -ENOTSUPP;
2216                 ep->driver_data = func->eps + idx;
2217
2218                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2219                 if (unlikely(!req))
2220                         return -ENOMEM;
2221
2222                 ffs_ep->ep  = ep;
2223                 ffs_ep->req = req;
2224                 func->eps_revmap[ds->bEndpointAddress &
2225                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2226         }
2227         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2228
2229         return 0;
2230 }
2231
2232 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2233                                    struct usb_descriptor_header *desc,
2234                                    void *priv)
2235 {
2236         struct ffs_function *func = priv;
2237         unsigned idx;
2238         u8 newValue;
2239
2240         switch (type) {
2241         default:
2242         case FFS_DESCRIPTOR:
2243                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2244                 return 0;
2245
2246         case FFS_INTERFACE:
2247                 idx = *valuep;
2248                 if (func->interfaces_nums[idx] < 0) {
2249                         int id = usb_interface_id(func->conf, &func->function);
2250                         if (unlikely(id < 0))
2251                                 return id;
2252                         func->interfaces_nums[idx] = id;
2253                 }
2254                 newValue = func->interfaces_nums[idx];
2255                 break;
2256
2257         case FFS_STRING:
2258                 /* String' IDs are allocated when fsf_data is bound to cdev */
2259                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2260                 break;
2261
2262         case FFS_ENDPOINT:
2263                 /*
2264                  * USB_DT_ENDPOINT are handled in
2265                  * __ffs_func_bind_do_descs().
2266                  */
2267                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2268                         return 0;
2269
2270                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2271                 if (unlikely(!func->eps[idx].ep))
2272                         return -EINVAL;
2273
2274                 {
2275                         struct usb_endpoint_descriptor **descs;
2276                         descs = func->eps[idx].descs;
2277                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2278                 }
2279                 break;
2280         }
2281
2282         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2283         *valuep = newValue;
2284         return 0;
2285 }
2286
2287 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2288                                                 struct usb_configuration *c)
2289 {
2290         struct ffs_function *func = ffs_func_from_usb(f);
2291         struct f_fs_opts *ffs_opts =
2292                 container_of(f->fi, struct f_fs_opts, func_inst);
2293         int ret;
2294
2295         ENTER();
2296
2297         /*
2298          * Legacy gadget triggers binding in functionfs_ready_callback,
2299          * which already uses locking; taking the same lock here would
2300          * cause a deadlock.
2301          *
2302          * Configfs-enabled gadgets however do need ffs_dev_lock.
2303          */
2304         if (!ffs_opts->no_configfs)
2305                 ffs_dev_lock();
2306         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2307         func->ffs = ffs_opts->dev->ffs_data;
2308         if (!ffs_opts->no_configfs)
2309                 ffs_dev_unlock();
2310         if (ret)
2311                 return ERR_PTR(ret);
2312
2313         func->conf = c;
2314         func->gadget = c->cdev->gadget;
2315
2316         ffs_data_get(func->ffs);
2317
2318         /*
2319          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2320          * configurations are bound in sequence with list_for_each_entry,
2321          * in each configuration its functions are bound in sequence
2322          * with list_for_each_entry, so we assume no race condition
2323          * with regard to ffs_opts->bound access
2324          */
2325         if (!ffs_opts->refcnt) {
2326                 ret = functionfs_bind(func->ffs, c->cdev);
2327                 if (ret)
2328                         return ERR_PTR(ret);
2329         }
2330         ffs_opts->refcnt++;
2331         func->function.strings = func->ffs->stringtabs;
2332
2333         return ffs_opts;
2334 }
2335
2336 static int _ffs_func_bind(struct usb_configuration *c,
2337                           struct usb_function *f)
2338 {
2339         struct ffs_function *func = ffs_func_from_usb(f);
2340         struct ffs_data *ffs = func->ffs;
2341
2342         const int full = !!func->ffs->fs_descs_count;
2343         const int high = gadget_is_dualspeed(func->gadget) &&
2344                 func->ffs->hs_descs_count;
2345         const int super = gadget_is_superspeed(func->gadget) &&
2346                 func->ffs->ss_descs_count;
2347
2348         int fs_len, hs_len, ret;
2349
2350         /* Make it a single chunk, less management later on */
2351         vla_group(d);
2352         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2353         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2354                 full ? ffs->fs_descs_count + 1 : 0);
2355         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2356                 high ? ffs->hs_descs_count + 1 : 0);
2357         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2358                 super ? ffs->ss_descs_count + 1 : 0);
2359         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2360         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2361         char *vlabuf;
2362
2363         ENTER();
2364
2365         /* Has descriptors only for speeds gadget does not support */
2366         if (unlikely(!(full | high | super)))
2367                 return -ENOTSUPP;
2368
2369         /* Allocate a single chunk, less management later on */
2370         vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2371         if (unlikely(!vlabuf))
2372                 return -ENOMEM;
2373
2374         /* Zero */
2375         memset(vla_ptr(vlabuf, d, eps), 0, d_eps__sz);
2376         /* Copy descriptors  */
2377         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
2378                ffs->raw_descs_length);
2379
2380         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2381         for (ret = ffs->eps_count; ret; --ret) {
2382                 struct ffs_ep *ptr;
2383
2384                 ptr = vla_ptr(vlabuf, d, eps);
2385                 ptr[ret].num = -1;
2386         }
2387
2388         /* Save pointers
2389          * d_eps == vlabuf, func->eps used to kfree vlabuf later
2390         */
2391         func->eps             = vla_ptr(vlabuf, d, eps);
2392         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
2393
2394         /*
2395          * Go through all the endpoint descriptors and allocate
2396          * endpoints first, so that later we can rewrite the endpoint
2397          * numbers without worrying that it may be described later on.
2398          */
2399         if (likely(full)) {
2400                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
2401                 fs_len = ffs_do_descs(ffs->fs_descs_count,
2402                                       vla_ptr(vlabuf, d, raw_descs),
2403                                       d_raw_descs__sz,
2404                                       __ffs_func_bind_do_descs, func);
2405                 if (unlikely(fs_len < 0)) {
2406                         ret = fs_len;
2407                         goto error;
2408                 }
2409         } else {
2410                 fs_len = 0;
2411         }
2412
2413         if (likely(high)) {
2414                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
2415                 hs_len = ffs_do_descs(ffs->hs_descs_count,
2416                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
2417                                       d_raw_descs__sz - fs_len,
2418                                       __ffs_func_bind_do_descs, func);
2419                 if (unlikely(hs_len < 0)) {
2420                         ret = hs_len;
2421                         goto error;
2422                 }
2423         } else {
2424                 hs_len = 0;
2425         }
2426
2427         if (likely(super)) {
2428                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
2429                 ret = ffs_do_descs(ffs->ss_descs_count,
2430                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
2431                                 d_raw_descs__sz - fs_len - hs_len,
2432                                 __ffs_func_bind_do_descs, func);
2433                 if (unlikely(ret < 0))
2434                         goto error;
2435         }
2436
2437         /*
2438          * Now handle interface numbers allocation and interface and
2439          * endpoint numbers rewriting.  We can do that in one go
2440          * now.
2441          */
2442         ret = ffs_do_descs(ffs->fs_descs_count +
2443                            (high ? ffs->hs_descs_count : 0) +
2444                            (super ? ffs->ss_descs_count : 0),
2445                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
2446                            __ffs_func_bind_do_nums, func);
2447         if (unlikely(ret < 0))
2448                 goto error;
2449
2450         /* And we're done */
2451         ffs_event_add(ffs, FUNCTIONFS_BIND);
2452         return 0;
2453
2454 error:
2455         /* XXX Do we need to release all claimed endpoints here? */
2456         return ret;
2457 }
2458
2459 static int ffs_func_bind(struct usb_configuration *c,
2460                          struct usb_function *f)
2461 {
2462         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
2463
2464         if (IS_ERR(ffs_opts))
2465                 return PTR_ERR(ffs_opts);
2466
2467         return _ffs_func_bind(c, f);
2468 }
2469
2470
2471 /* Other USB function hooks *************************************************/
2472
2473 static int ffs_func_set_alt(struct usb_function *f,
2474                             unsigned interface, unsigned alt)
2475 {
2476         struct ffs_function *func = ffs_func_from_usb(f);
2477         struct ffs_data *ffs = func->ffs;
2478         int ret = 0, intf;
2479
2480         if (alt != (unsigned)-1) {
2481                 intf = ffs_func_revmap_intf(func, interface);
2482                 if (unlikely(intf < 0))
2483                         return intf;
2484         }
2485
2486         if (ffs->func)
2487                 ffs_func_eps_disable(ffs->func);
2488
2489         if (ffs->state != FFS_ACTIVE)
2490                 return -ENODEV;
2491
2492         if (alt == (unsigned)-1) {
2493                 ffs->func = NULL;
2494                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2495                 return 0;
2496         }
2497
2498         ffs->func = func;
2499         ret = ffs_func_eps_enable(func);
2500         if (likely(ret >= 0))
2501                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2502         return ret;
2503 }
2504
2505 static void ffs_func_disable(struct usb_function *f)
2506 {
2507         ffs_func_set_alt(f, 0, (unsigned)-1);
2508 }
2509
2510 static int ffs_func_setup(struct usb_function *f,
2511                           const struct usb_ctrlrequest *creq)
2512 {
2513         struct ffs_function *func = ffs_func_from_usb(f);
2514         struct ffs_data *ffs = func->ffs;
2515         unsigned long flags;
2516         int ret;
2517
2518         ENTER();
2519
2520         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2521         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2522         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2523         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
2524         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
2525
2526         /*
2527          * Most requests directed to interface go through here
2528          * (notable exceptions are set/get interface) so we need to
2529          * handle them.  All other either handled by composite or
2530          * passed to usb_configuration->setup() (if one is set).  No
2531          * matter, we will handle requests directed to endpoint here
2532          * as well (as it's straightforward) but what to do with any
2533          * other request?
2534          */
2535         if (ffs->state != FFS_ACTIVE)
2536                 return -ENODEV;
2537
2538         switch (creq->bRequestType & USB_RECIP_MASK) {
2539         case USB_RECIP_INTERFACE:
2540                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
2541                 if (unlikely(ret < 0))
2542                         return ret;
2543                 break;
2544
2545         case USB_RECIP_ENDPOINT:
2546                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
2547                 if (unlikely(ret < 0))
2548                         return ret;
2549                 break;
2550
2551         default:
2552                 return -EOPNOTSUPP;
2553         }
2554
2555         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2556         ffs->ev.setup = *creq;
2557         ffs->ev.setup.wIndex = cpu_to_le16(ret);
2558         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
2559         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2560
2561         return 0;
2562 }
2563
2564 static void ffs_func_suspend(struct usb_function *f)
2565 {
2566         ENTER();
2567         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
2568 }
2569
2570 static void ffs_func_resume(struct usb_function *f)
2571 {
2572         ENTER();
2573         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
2574 }
2575
2576
2577 /* Endpoint and interface numbers reverse mapping ***************************/
2578
2579 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
2580 {
2581         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
2582         return num ? num : -EDOM;
2583 }
2584
2585 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
2586 {
2587         short *nums = func->interfaces_nums;
2588         unsigned count = func->ffs->interfaces_count;
2589
2590         for (; count; --count, ++nums) {
2591                 if (*nums >= 0 && *nums == intf)
2592                         return nums - func->interfaces_nums;
2593         }
2594
2595         return -EDOM;
2596 }
2597
2598
2599 /* Devices management *******************************************************/
2600
2601 static LIST_HEAD(ffs_devices);
2602
2603 static struct ffs_dev *_ffs_do_find_dev(const char *name)
2604 {
2605         struct ffs_dev *dev;
2606
2607         list_for_each_entry(dev, &ffs_devices, entry) {
2608                 if (!dev->name || !name)
2609                         continue;
2610                 if (strcmp(dev->name, name) == 0)
2611                         return dev;
2612         }
2613
2614         return NULL;
2615 }
2616
2617 /*
2618  * ffs_lock must be taken by the caller of this function
2619  */
2620 static struct ffs_dev *_ffs_get_single_dev(void)
2621 {
2622         struct ffs_dev *dev;
2623
2624         if (list_is_singular(&ffs_devices)) {
2625                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
2626                 if (dev->single)
2627                         return dev;
2628         }
2629
2630         return NULL;
2631 }
2632
2633 /*
2634  * ffs_lock must be taken by the caller of this function
2635  */
2636 static struct ffs_dev *_ffs_find_dev(const char *name)
2637 {
2638         struct ffs_dev *dev;
2639
2640         dev = _ffs_get_single_dev();
2641         if (dev)
2642                 return dev;
2643
2644         return _ffs_do_find_dev(name);
2645 }
2646
2647 /* Configfs support *********************************************************/
2648
2649 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
2650 {
2651         return container_of(to_config_group(item), struct f_fs_opts,
2652                             func_inst.group);
2653 }
2654
2655 static void ffs_attr_release(struct config_item *item)
2656 {
2657         struct f_fs_opts *opts = to_ffs_opts(item);
2658
2659         usb_put_function_instance(&opts->func_inst);
2660 }
2661
2662 static struct configfs_item_operations ffs_item_ops = {
2663         .release        = ffs_attr_release,
2664 };
2665
2666 static struct config_item_type ffs_func_type = {
2667         .ct_item_ops    = &ffs_item_ops,
2668         .ct_owner       = THIS_MODULE,
2669 };
2670
2671
2672 /* Function registration interface ******************************************/
2673
2674 static void ffs_free_inst(struct usb_function_instance *f)
2675 {
2676         struct f_fs_opts *opts;
2677
2678         opts = to_f_fs_opts(f);
2679         ffs_dev_lock();
2680         _ffs_free_dev(opts->dev);
2681         ffs_dev_unlock();
2682         kfree(opts);
2683 }
2684
2685 #define MAX_INST_NAME_LEN       40
2686
2687 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
2688 {
2689         struct f_fs_opts *opts;
2690         char *ptr;
2691         const char *tmp;
2692         int name_len, ret;
2693
2694         name_len = strlen(name) + 1;
2695         if (name_len > MAX_INST_NAME_LEN)
2696                 return -ENAMETOOLONG;
2697
2698         ptr = kstrndup(name, name_len, GFP_KERNEL);
2699         if (!ptr)
2700                 return -ENOMEM;
2701
2702         opts = to_f_fs_opts(fi);
2703         tmp = NULL;
2704
2705         ffs_dev_lock();
2706
2707         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
2708         ret = _ffs_name_dev(opts->dev, ptr);
2709         if (ret) {
2710                 kfree(ptr);
2711                 ffs_dev_unlock();
2712                 return ret;
2713         }
2714         opts->dev->name_allocated = true;
2715
2716         ffs_dev_unlock();
2717
2718         kfree(tmp);
2719
2720         return 0;
2721 }
2722
2723 static struct usb_function_instance *ffs_alloc_inst(void)
2724 {
2725         struct f_fs_opts *opts;
2726         struct ffs_dev *dev;
2727
2728         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
2729         if (!opts)
2730                 return ERR_PTR(-ENOMEM);
2731
2732         opts->func_inst.set_inst_name = ffs_set_inst_name;
2733         opts->func_inst.free_func_inst = ffs_free_inst;
2734         ffs_dev_lock();
2735         dev = _ffs_alloc_dev();
2736         ffs_dev_unlock();
2737         if (IS_ERR(dev)) {
2738                 kfree(opts);
2739                 return ERR_CAST(dev);
2740         }
2741         opts->dev = dev;
2742         dev->opts = opts;
2743
2744         config_group_init_type_name(&opts->func_inst.group, "",
2745                                     &ffs_func_type);
2746         return &opts->func_inst;
2747 }
2748
2749 static void ffs_free(struct usb_function *f)
2750 {
2751         kfree(ffs_func_from_usb(f));
2752 }
2753
2754 static void ffs_func_unbind(struct usb_configuration *c,
2755                             struct usb_function *f)
2756 {
2757         struct ffs_function *func = ffs_func_from_usb(f);
2758         struct ffs_data *ffs = func->ffs;
2759         struct f_fs_opts *opts =
2760                 container_of(f->fi, struct f_fs_opts, func_inst);
2761         struct ffs_ep *ep = func->eps;
2762         unsigned count = ffs->eps_count;
2763         unsigned long flags;
2764
2765         ENTER();
2766         if (ffs->func == func) {
2767                 ffs_func_eps_disable(func);
2768                 ffs->func = NULL;
2769         }
2770
2771         if (!--opts->refcnt)
2772                 functionfs_unbind(ffs);
2773
2774         /* cleanup after autoconfig */
2775         spin_lock_irqsave(&func->ffs->eps_lock, flags);
2776         do {
2777                 if (ep->ep && ep->req)
2778                         usb_ep_free_request(ep->ep, ep->req);
2779                 ep->req = NULL;
2780                 ++ep;
2781         } while (--count);
2782         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2783         kfree(func->eps);
2784         func->eps = NULL;
2785         /*
2786          * eps, descriptors and interfaces_nums are allocated in the
2787          * same chunk so only one free is required.
2788          */
2789         func->function.fs_descriptors = NULL;
2790         func->function.hs_descriptors = NULL;
2791         func->function.ss_descriptors = NULL;
2792         func->interfaces_nums = NULL;
2793
2794         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
2795 }
2796
2797 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
2798 {
2799         struct ffs_function *func;
2800
2801         ENTER();
2802
2803         func = kzalloc(sizeof(*func), GFP_KERNEL);
2804         if (unlikely(!func))
2805                 return ERR_PTR(-ENOMEM);
2806
2807         func->function.name    = "Function FS Gadget";
2808
2809         func->function.bind    = ffs_func_bind;
2810         func->function.unbind  = ffs_func_unbind;
2811         func->function.set_alt = ffs_func_set_alt;
2812         func->function.disable = ffs_func_disable;
2813         func->function.setup   = ffs_func_setup;
2814         func->function.suspend = ffs_func_suspend;
2815         func->function.resume  = ffs_func_resume;
2816         func->function.free_func = ffs_free;
2817
2818         return &func->function;
2819 }
2820
2821 /*
2822  * ffs_lock must be taken by the caller of this function
2823  */
2824 static struct ffs_dev *_ffs_alloc_dev(void)
2825 {
2826         struct ffs_dev *dev;
2827         int ret;
2828
2829         if (_ffs_get_single_dev())
2830                         return ERR_PTR(-EBUSY);
2831
2832         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2833         if (!dev)
2834                 return ERR_PTR(-ENOMEM);
2835
2836         if (list_empty(&ffs_devices)) {
2837                 ret = functionfs_init();
2838                 if (ret) {
2839                         kfree(dev);
2840                         return ERR_PTR(ret);
2841                 }
2842         }
2843
2844         list_add(&dev->entry, &ffs_devices);
2845
2846         return dev;
2847 }
2848
2849 /*
2850  * ffs_lock must be taken by the caller of this function
2851  * The caller is responsible for "name" being available whenever f_fs needs it
2852  */
2853 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
2854 {
2855         struct ffs_dev *existing;
2856
2857         existing = _ffs_do_find_dev(name);
2858         if (existing)
2859                 return -EBUSY;
2860
2861         dev->name = name;
2862
2863         return 0;
2864 }
2865
2866 /*
2867  * The caller is responsible for "name" being available whenever f_fs needs it
2868  */
2869 int ffs_name_dev(struct ffs_dev *dev, const char *name)
2870 {
2871         int ret;
2872
2873         ffs_dev_lock();
2874         ret = _ffs_name_dev(dev, name);
2875         ffs_dev_unlock();
2876
2877         return ret;
2878 }
2879 EXPORT_SYMBOL(ffs_name_dev);
2880
2881 int ffs_single_dev(struct ffs_dev *dev)
2882 {
2883         int ret;
2884
2885         ret = 0;
2886         ffs_dev_lock();
2887
2888         if (!list_is_singular(&ffs_devices))
2889                 ret = -EBUSY;
2890         else
2891                 dev->single = true;
2892
2893         ffs_dev_unlock();
2894         return ret;
2895 }
2896 EXPORT_SYMBOL(ffs_single_dev);
2897
2898 /*
2899  * ffs_lock must be taken by the caller of this function
2900  */
2901 static void _ffs_free_dev(struct ffs_dev *dev)
2902 {
2903         list_del(&dev->entry);
2904         if (dev->name_allocated)
2905                 kfree(dev->name);
2906         kfree(dev);
2907         if (list_empty(&ffs_devices))
2908                 functionfs_cleanup();
2909 }
2910
2911 static void *ffs_acquire_dev(const char *dev_name)
2912 {
2913         struct ffs_dev *ffs_dev;
2914
2915         ENTER();
2916         ffs_dev_lock();
2917
2918         ffs_dev = _ffs_find_dev(dev_name);
2919         if (!ffs_dev)
2920                 ffs_dev = ERR_PTR(-ENODEV);
2921         else if (ffs_dev->mounted)
2922                 ffs_dev = ERR_PTR(-EBUSY);
2923         else if (ffs_dev->ffs_acquire_dev_callback &&
2924             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
2925                 ffs_dev = ERR_PTR(-ENODEV);
2926         else
2927                 ffs_dev->mounted = true;
2928
2929         ffs_dev_unlock();
2930         return ffs_dev;
2931 }
2932
2933 static void ffs_release_dev(struct ffs_data *ffs_data)
2934 {
2935         struct ffs_dev *ffs_dev;
2936
2937         ENTER();
2938         ffs_dev_lock();
2939
2940         ffs_dev = ffs_data->private_data;
2941         if (ffs_dev) {
2942                 ffs_dev->mounted = false;
2943
2944                 if (ffs_dev->ffs_release_dev_callback)
2945                         ffs_dev->ffs_release_dev_callback(ffs_dev);
2946         }
2947
2948         ffs_dev_unlock();
2949 }
2950
2951 static int ffs_ready(struct ffs_data *ffs)
2952 {
2953         struct ffs_dev *ffs_obj;
2954         int ret = 0;
2955
2956         ENTER();
2957         ffs_dev_lock();
2958
2959         ffs_obj = ffs->private_data;
2960         if (!ffs_obj) {
2961                 ret = -EINVAL;
2962                 goto done;
2963         }
2964         if (WARN_ON(ffs_obj->desc_ready)) {
2965                 ret = -EBUSY;
2966                 goto done;
2967         }
2968
2969         ffs_obj->desc_ready = true;
2970         ffs_obj->ffs_data = ffs;
2971
2972         if (ffs_obj->ffs_ready_callback)
2973                 ret = ffs_obj->ffs_ready_callback(ffs);
2974
2975 done:
2976         ffs_dev_unlock();
2977         return ret;
2978 }
2979
2980 static void ffs_closed(struct ffs_data *ffs)
2981 {
2982         struct ffs_dev *ffs_obj;
2983
2984         ENTER();
2985         ffs_dev_lock();
2986
2987         ffs_obj = ffs->private_data;
2988         if (!ffs_obj)
2989                 goto done;
2990
2991         ffs_obj->desc_ready = false;
2992
2993         if (ffs_obj->ffs_closed_callback)
2994                 ffs_obj->ffs_closed_callback(ffs);
2995
2996         if (!ffs_obj->opts || ffs_obj->opts->no_configfs
2997             || !ffs_obj->opts->func_inst.group.cg_item.ci_parent)
2998                 goto done;
2999
3000         unregister_gadget_item(ffs_obj->opts->
3001                                func_inst.group.cg_item.ci_parent->ci_parent);
3002 done:
3003         ffs_dev_unlock();
3004 }
3005
3006 /* Misc helper functions ****************************************************/
3007
3008 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3009 {
3010         return nonblock
3011                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3012                 : mutex_lock_interruptible(mutex);
3013 }
3014
3015 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3016 {
3017         char *data;
3018
3019         if (unlikely(!len))
3020                 return NULL;
3021
3022         data = kmalloc(len, GFP_KERNEL);
3023         if (unlikely(!data))
3024                 return ERR_PTR(-ENOMEM);
3025
3026         if (unlikely(__copy_from_user(data, buf, len))) {
3027                 kfree(data);
3028                 return ERR_PTR(-EFAULT);
3029         }
3030
3031         pr_vdebug("Buffer from user space:\n");
3032         ffs_dump_mem("", data, len);
3033
3034         return data;
3035 }
3036
3037 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3038 MODULE_LICENSE("GPL");
3039 MODULE_AUTHOR("Michal Nazarewicz");