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                 spin_lock_irq(&epfile->ffs->eps_lock);
 749                 /* In the meantime, endpoint got disabled or changed. */
 750                 if (epfile->ep != ep) {
 751                         spin_unlock_irq(&epfile->ffs->eps_lock);
 752                         return -ESHUTDOWN;
 753                 }
 754                 /*
 755                  * Controller may require buffer size to be aligned to
 756                  * maxpacketsize of an out endpoint.
 757                  */
 758                 data_len = io_data->read ?
 759                            usb_ep_align_maybe(gadget, ep->ep, io_data->len) :
 760                            io_data->len;
 761                 spin_unlock_irq(&epfile->ffs->eps_lock);
 762
 763                 data = kmalloc(data_len, GFP_KERNEL);
 764                 if (unlikely(!data))
 765                         return -ENOMEM;
 766                 if (io_data->aio && !io_data->read) {
 767                         int i;
 768                         size_t pos = 0;
 769                         for (i = 0; i < io_data->nr_segs; i++) {
 770                                 if (unlikely(copy_from_user(&data[pos],
 771                                              io_data->iovec[i].iov_base,
 772                                              io_data->iovec[i].iov_len))) {
 773                                         ret = -EFAULT;
 774                                         goto error;
 775                                 }
 776                                 pos += io_data->iovec[i].iov_len;
 777                         }
 778                 } else {
 779                         if (!io_data->read &&
 780                             unlikely(__copy_from_user(data, io_data->buf,
 781                                                       io_data->len))) {
 782                                 ret = -EFAULT;
 783                                 goto error;
 784                         }
 785                 }
 786         }
 787
 788         /* We will be using request */
 789         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 790         if (unlikely(ret))
 791                 goto error;
 792
 793         spin_lock_irq(&epfile->ffs->eps_lock);
 794
 795         if (epfile->ep != ep) {
 796                 /* In the meantime, endpoint got disabled or changed. */
 797                 ret = -ESHUTDOWN;
 798                 spin_unlock_irq(&epfile->ffs->eps_lock);
 799         } else if (halt) {
 800                 /* Halt */
 801                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 802                         usb_ep_set_halt(ep->ep);
 803                 spin_unlock_irq(&epfile->ffs->eps_lock);
 804                 ret = -EBADMSG;
 805         } else {
 806                 /* Fire the request */
 807                 struct usb_request *req;
 808
 809                 if (io_data->aio) {
 810                         req = usb_ep_alloc_request(ep->ep, GFP_KERNEL);
 811                         if (unlikely(!req))
 812                                 goto error_lock;
 813
 814                         req->buf      = data;
 815                         req->length   = io_data->len;
 816
 817                         io_data->buf = data;
 818                         io_data->ep = ep->ep;
 819                         io_data->req = req;
 820
 821                         req->context  = io_data;
 822                         req->complete = ffs_epfile_async_io_complete;
 823
 824                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 825                         if (unlikely(ret)) {
 826                                 usb_ep_free_request(ep->ep, req);
 827                                 goto error_lock;
 828                         }
 829                         ret = -EIOCBQUEUED;
 830
 831                         spin_unlock_irq(&epfile->ffs->eps_lock);
 832                 } else {
 833                         DECLARE_COMPLETION_ONSTACK(done);
 834
 835                         req = ep->req;
 836                         req->buf      = data;
 837                         req->length   = io_data->len;
 838
 839                         req->context  = &done;
 840                         req->complete = ffs_epfile_io_complete;
 841
 842                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 843
 844                         spin_unlock_irq(&epfile->ffs->eps_lock);
 845
 846                         if (unlikely(ret < 0)) {
 847                                 /* nop */
 848                         } else if (unlikely(
 849                                    wait_for_completion_interruptible(&done))) {
 850                                 ret = -EINTR;
 851                                 usb_ep_dequeue(ep->ep, req);
 852                         } else {
 853                                 /*
 854                                  * XXX We may end up silently droping data
 855                                  * here.  Since data_len (i.e. req->length) may
 856                                  * be bigger than len (after being rounded up
 857                                  * to maxpacketsize), we may end up with more
 858                                  * data then user space has space for.
 859                                  */
 860                                 ret = ep->status;
 861                                 if (io_data->read && ret > 0) {
 862                                         ret = min_t(size_t, ret, io_data->len);
 863
 864                                         if (unlikely(copy_to_user(io_data->buf,
 865                                                 data, ret)))
 866                                                 ret = -EFAULT;
 867                                 }
 868                         }
 869                         kfree(data);
 870                 }
 871         }
 872
 873         mutex_unlock(&epfile->mutex);
 874         return ret;
 875
 876 error_lock:
 877         spin_unlock_irq(&epfile->ffs->eps_lock);
 878         mutex_unlock(&epfile->mutex);
 879 error:
 880         kfree(data);
 881         return ret;
 882 }
 883
 884 static ssize_t
 885 ffs_epfile_write(struct file *file, const char __user *buf, size_t len,
 886                  loff_t *ptr)
 887 {
 888         struct ffs_io_data io_data;
 889
 890         ENTER();
 891
 892         io_data.aio = false;
 893         io_data.read = false;
 894         io_data.buf = (char * __user)buf;
 895         io_data.len = len;
 896
 897         return ffs_epfile_io(file, &io_data);
 898 }
 899
 900 static ssize_t
 901 ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr)
 902 {
 903         struct ffs_io_data io_data;
 904
 905         ENTER();
 906
 907         io_data.aio = false;
 908         io_data.read = true;
 909         io_data.buf = buf;
 910         io_data.len = len;
 911
 912         return ffs_epfile_io(file, &io_data);
 913 }
 914
 915 static int
 916 ffs_epfile_open(struct inode *inode, struct file *file)
 917 {
 918         struct ffs_epfile *epfile = inode->i_private;
 919
 920         ENTER();
 921
 922         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 923                 return -ENODEV;
 924
 925         file->private_data = epfile;
 926         ffs_data_opened(epfile->ffs);
 927
 928         return 0;
 929 }
 930
 931 static int ffs_aio_cancel(struct kiocb *kiocb)
 932 {
 933         struct ffs_io_data *io_data = kiocb->private;
 934         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
 935         int value;
 936
 937         ENTER();
 938
 939         spin_lock_irq(&epfile->ffs->eps_lock);
 940
 941         if (likely(io_data && io_data->ep && io_data->req))
 942                 value = usb_ep_dequeue(io_data->ep, io_data->req);
 943         else
 944                 value = -EINVAL;
 945
 946         spin_unlock_irq(&epfile->ffs->eps_lock);
 947
 948         return value;
 949 }
 950
 951 static ssize_t ffs_epfile_aio_write(struct kiocb *kiocb,
 952                                     const struct iovec *iovec,
 953                                     unsigned long nr_segs, loff_t loff)
 954 {
 955         struct ffs_io_data *io_data;
 956
 957         ENTER();
 958
 959         io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
 960         if (unlikely(!io_data))
 961                 return -ENOMEM;
 962
 963         io_data->aio = true;
 964         io_data->read = false;
 965         io_data->kiocb = kiocb;
 966         io_data->iovec = iovec;
 967         io_data->nr_segs = nr_segs;
 968         io_data->len = kiocb->ki_nbytes;
 969         io_data->mm = current->mm;
 970
 971         kiocb->private = io_data;
 972
 973         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 974
 975         return ffs_epfile_io(kiocb->ki_filp, io_data);
 976 }
 977
 978 static ssize_t ffs_epfile_aio_read(struct kiocb *kiocb,
 979                                    const struct iovec *iovec,
 980                                    unsigned long nr_segs, loff_t loff)
 981 {
 982         struct ffs_io_data *io_data;
 983         struct iovec *iovec_copy;
 984
 985         ENTER();
 986
 987         iovec_copy = kmalloc_array(nr_segs, sizeof(*iovec_copy), GFP_KERNEL);
 988         if (unlikely(!iovec_copy))
 989                 return -ENOMEM;
 990
 991         memcpy(iovec_copy, iovec, sizeof(struct iovec)*nr_segs);
 992
 993         io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
 994         if (unlikely(!io_data)) {
 995                 kfree(iovec_copy);
 996                 return -ENOMEM;
 997         }
 998
 999         io_data->aio = true;
1000         io_data->read = true;
1001         io_data->kiocb = kiocb;
1002         io_data->iovec = iovec_copy;
1003         io_data->nr_segs = nr_segs;
1004         io_data->len = kiocb->ki_nbytes;
1005         io_data->mm = current->mm;
1006
1007         kiocb->private = io_data;
1008
1009         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1010
1011         return ffs_epfile_io(kiocb->ki_filp, io_data);
1012 }
1013
1014 static int
1015 ffs_epfile_release(struct inode *inode, struct file *file)
1016 {
1017         struct ffs_epfile *epfile = inode->i_private;
1018
1019         ENTER();
1020
1021         ffs_data_closed(epfile->ffs);
1022
1023         return 0;
1024 }
1025
1026 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1027                              unsigned long value)
1028 {
1029         struct ffs_epfile *epfile = file->private_data;
1030         int ret;
1031
1032         ENTER();
1033
1034         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1035                 return -ENODEV;
1036
1037         spin_lock_irq(&epfile->ffs->eps_lock);
1038         if (likely(epfile->ep)) {
1039                 switch (code) {
1040                 case FUNCTIONFS_FIFO_STATUS:
1041                         ret = usb_ep_fifo_status(epfile->ep->ep);
1042                         break;
1043                 case FUNCTIONFS_FIFO_FLUSH:
1044                         usb_ep_fifo_flush(epfile->ep->ep);
1045                         ret = 0;
1046                         break;
1047                 case FUNCTIONFS_CLEAR_HALT:
1048                         ret = usb_ep_clear_halt(epfile->ep->ep);
1049                         break;
1050                 case FUNCTIONFS_ENDPOINT_REVMAP:
1051                         ret = epfile->ep->num;
1052                         break;
1053                 default:
1054                         ret = -ENOTTY;
1055                 }
1056         } else {
1057                 ret = -ENODEV;
1058         }
1059         spin_unlock_irq(&epfile->ffs->eps_lock);
1060
1061         return ret;
1062 }
1063
1064 static const struct file_operations ffs_epfile_operations = {
1065         .llseek =       no_llseek,
1066
1067         .open =         ffs_epfile_open,
1068         .write =        ffs_epfile_write,
1069         .read =         ffs_epfile_read,
1070         .aio_write =    ffs_epfile_aio_write,
1071         .aio_read =     ffs_epfile_aio_read,
1072         .release =      ffs_epfile_release,
1073         .unlocked_ioctl =       ffs_epfile_ioctl,
1074 };
1075
1076
1077 /* File system and super block operations ***********************************/
1078
1079 /*
1080  * Mounting the file system creates a controller file, used first for
1081  * function configuration then later for event monitoring.
1082  */
1083
1084 static struct inode *__must_check
1085 ffs_sb_make_inode(struct super_block *sb, void *data,
1086                   const struct file_operations *fops,
1087                   const struct inode_operations *iops,
1088                   struct ffs_file_perms *perms)
1089 {
1090         struct inode *inode;
1091
1092         ENTER();
1093
1094         inode = new_inode(sb);
1095
1096         if (likely(inode)) {
1097                 struct timespec current_time = CURRENT_TIME;
1098
1099                 inode->i_ino     = get_next_ino();
1100                 inode->i_mode    = perms->mode;
1101                 inode->i_uid     = perms->uid;
1102                 inode->i_gid     = perms->gid;
1103                 inode->i_atime   = current_time;
1104                 inode->i_mtime   = current_time;
1105                 inode->i_ctime   = current_time;
1106                 inode->i_private = data;
1107                 if (fops)
1108                         inode->i_fop = fops;
1109                 if (iops)
1110                         inode->i_op  = iops;
1111         }
1112
1113         return inode;
1114 }
1115
1116 /* Create "regular" file */
1117 static struct inode *ffs_sb_create_file(struct super_block *sb,
1118                                         const char *name, void *data,
1119                                         const struct file_operations *fops,
1120                                         struct dentry **dentry_p)
1121 {
1122         struct ffs_data *ffs = sb->s_fs_info;
1123         struct dentry   *dentry;
1124         struct inode    *inode;
1125
1126         ENTER();
1127
1128         dentry = d_alloc_name(sb->s_root, name);
1129         if (unlikely(!dentry))
1130                 return NULL;
1131
1132         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1133         if (unlikely(!inode)) {
1134                 dput(dentry);
1135                 return NULL;
1136         }
1137
1138         d_add(dentry, inode);
1139         if (dentry_p)
1140                 *dentry_p = dentry;
1141
1142         return inode;
1143 }
1144
1145 /* Super block */
1146 static const struct super_operations ffs_sb_operations = {
1147         .statfs =       simple_statfs,
1148         .drop_inode =   generic_delete_inode,
1149 };
1150
1151 struct ffs_sb_fill_data {
1152         struct ffs_file_perms perms;
1153         umode_t root_mode;
1154         const char *dev_name;
1155         struct ffs_data *ffs_data;
1156 };
1157
1158 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1159 {
1160         struct ffs_sb_fill_data *data = _data;
1161         struct inode    *inode;
1162         struct ffs_data *ffs = data->ffs_data;
1163
1164         ENTER();
1165
1166         ffs->sb              = sb;
1167         data->ffs_data       = NULL;
1168         sb->s_fs_info        = ffs;
1169         sb->s_blocksize      = PAGE_CACHE_SIZE;
1170         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1171         sb->s_magic          = FUNCTIONFS_MAGIC;
1172         sb->s_op             = &ffs_sb_operations;
1173         sb->s_time_gran      = 1;
1174
1175         /* Root inode */
1176         data->perms.mode = data->root_mode;
1177         inode = ffs_sb_make_inode(sb, NULL,
1178                                   &simple_dir_operations,
1179                                   &simple_dir_inode_operations,
1180                                   &data->perms);
1181         sb->s_root = d_make_root(inode);
1182         if (unlikely(!sb->s_root))
1183                 return -ENOMEM;
1184
1185         /* EP0 file */
1186         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1187                                          &ffs_ep0_operations, NULL)))
1188                 return -ENOMEM;
1189
1190         return 0;
1191 }
1192
1193 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1194 {
1195         ENTER();
1196
1197         if (!opts || !*opts)
1198                 return 0;
1199
1200         for (;;) {
1201                 unsigned long value;
1202                 char *eq, *comma;
1203
1204                 /* Option limit */
1205                 comma = strchr(opts, ',');
1206                 if (comma)
1207                         *comma = 0;
1208
1209                 /* Value limit */
1210                 eq = strchr(opts, '=');
1211                 if (unlikely(!eq)) {
1212                         pr_err("'=' missing in %s\n", opts);
1213                         return -EINVAL;
1214                 }
1215                 *eq = 0;
1216
1217                 /* Parse value */
1218                 if (kstrtoul(eq + 1, 0, &value)) {
1219                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1220                         return -EINVAL;
1221                 }
1222
1223                 /* Interpret option */
1224                 switch (eq - opts) {
1225                 case 5:
1226                         if (!memcmp(opts, "rmode", 5))
1227                                 data->root_mode  = (value & 0555) | S_IFDIR;
1228                         else if (!memcmp(opts, "fmode", 5))
1229                                 data->perms.mode = (value & 0666) | S_IFREG;
1230                         else
1231                                 goto invalid;
1232                         break;
1233
1234                 case 4:
1235                         if (!memcmp(opts, "mode", 4)) {
1236                                 data->root_mode  = (value & 0555) | S_IFDIR;
1237                                 data->perms.mode = (value & 0666) | S_IFREG;
1238                         } else {
1239                                 goto invalid;
1240                         }
1241                         break;
1242
1243                 case 3:
1244                         if (!memcmp(opts, "uid", 3)) {
1245                                 data->perms.uid = make_kuid(current_user_ns(), value);
1246                                 if (!uid_valid(data->perms.uid)) {
1247                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1248                                         return -EINVAL;
1249                                 }
1250                         } else if (!memcmp(opts, "gid", 3)) {
1251                                 data->perms.gid = make_kgid(current_user_ns(), value);
1252                                 if (!gid_valid(data->perms.gid)) {
1253                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1254                                         return -EINVAL;
1255                                 }
1256                         } else {
1257                                 goto invalid;
1258                         }
1259                         break;
1260
1261                 default:
1262 invalid:
1263                         pr_err("%s: invalid option\n", opts);
1264                         return -EINVAL;
1265                 }
1266
1267                 /* Next iteration */
1268                 if (!comma)
1269                         break;
1270                 opts = comma + 1;
1271         }
1272
1273         return 0;
1274 }
1275
1276 /* "mount -t functionfs dev_name /dev/function" ends up here */
1277
1278 static struct dentry *
1279 ffs_fs_mount(struct file_system_type *t, int flags,
1280               const char *dev_name, void *opts)
1281 {
1282         struct ffs_sb_fill_data data = {
1283                 .perms = {
1284                         .mode = S_IFREG | 0600,
1285                         .uid = GLOBAL_ROOT_UID,
1286                         .gid = GLOBAL_ROOT_GID,
1287                 },
1288                 .root_mode = S_IFDIR | 0500,
1289         };
1290         struct dentry *rv;
1291         int ret;
1292         void *ffs_dev;
1293         struct ffs_data *ffs;
1294
1295         ENTER();
1296
1297         ret = ffs_fs_parse_opts(&data, opts);
1298         if (unlikely(ret < 0))
1299                 return ERR_PTR(ret);
1300
1301         ffs = ffs_data_new();
1302         if (unlikely(!ffs))
1303                 return ERR_PTR(-ENOMEM);
1304         ffs->file_perms = data.perms;
1305
1306         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1307         if (unlikely(!ffs->dev_name)) {
1308                 ffs_data_put(ffs);
1309                 return ERR_PTR(-ENOMEM);
1310         }
1311
1312         ffs_dev = ffs_acquire_dev(dev_name);
1313         if (IS_ERR(ffs_dev)) {
1314                 ffs_data_put(ffs);
1315                 return ERR_CAST(ffs_dev);
1316         }
1317         ffs->private_data = ffs_dev;
1318         data.ffs_data = ffs;
1319
1320         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1321         if (IS_ERR(rv) && data.ffs_data) {
1322                 ffs_release_dev(data.ffs_data);
1323                 ffs_data_put(data.ffs_data);
1324         }
1325         return rv;
1326 }
1327
1328 static void
1329 ffs_fs_kill_sb(struct super_block *sb)
1330 {
1331         ENTER();
1332
1333         kill_litter_super(sb);
1334         if (sb->s_fs_info) {
1335                 ffs_release_dev(sb->s_fs_info);
1336                 ffs_data_put(sb->s_fs_info);
1337         }
1338 }
1339
1340 static struct file_system_type ffs_fs_type = {
1341         .owner          = THIS_MODULE,
1342         .name           = "functionfs",
1343         .mount          = ffs_fs_mount,
1344         .kill_sb        = ffs_fs_kill_sb,
1345 };
1346 MODULE_ALIAS_FS("functionfs");
1347
1348
1349 /* Driver's main init/cleanup functions *************************************/
1350
1351 static int functionfs_init(void)
1352 {
1353         int ret;
1354
1355         ENTER();
1356
1357         ret = register_filesystem(&ffs_fs_type);
1358         if (likely(!ret))
1359                 pr_info("file system registered\n");
1360         else
1361                 pr_err("failed registering file system (%d)\n", ret);
1362
1363         return ret;
1364 }
1365
1366 static void functionfs_cleanup(void)
1367 {
1368         ENTER();
1369
1370         pr_info("unloading\n");
1371         unregister_filesystem(&ffs_fs_type);
1372 }
1373
1374
1375 /* ffs_data and ffs_function construction and destruction code **************/
1376
1377 static void ffs_data_clear(struct ffs_data *ffs);
1378 static void ffs_data_reset(struct ffs_data *ffs);
1379
1380 static void ffs_data_get(struct ffs_data *ffs)
1381 {
1382         ENTER();
1383
1384         atomic_inc(&ffs->ref);
1385 }
1386
1387 static void ffs_data_opened(struct ffs_data *ffs)
1388 {
1389         ENTER();
1390
1391         atomic_inc(&ffs->ref);
1392         atomic_inc(&ffs->opened);
1393 }
1394
1395 static void ffs_data_put(struct ffs_data *ffs)
1396 {
1397         ENTER();
1398
1399         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1400                 pr_info("%s(): freeing\n", __func__);
1401                 ffs_data_clear(ffs);
1402                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1403                        waitqueue_active(&ffs->ep0req_completion.wait));
1404                 kfree(ffs->dev_name);
1405                 kfree(ffs);
1406         }
1407 }
1408
1409 static void ffs_data_closed(struct ffs_data *ffs)
1410 {
1411         ENTER();
1412
1413         if (atomic_dec_and_test(&ffs->opened)) {
1414                 ffs->state = FFS_CLOSING;
1415                 ffs_data_reset(ffs);
1416         }
1417
1418         ffs_data_put(ffs);
1419 }
1420
1421 static struct ffs_data *ffs_data_new(void)
1422 {
1423         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1424         if (unlikely(!ffs))
1425                 return NULL;
1426
1427         ENTER();
1428
1429         atomic_set(&ffs->ref, 1);
1430         atomic_set(&ffs->opened, 0);
1431         ffs->state = FFS_READ_DESCRIPTORS;
1432         mutex_init(&ffs->mutex);
1433         spin_lock_init(&ffs->eps_lock);
1434         init_waitqueue_head(&ffs->ev.waitq);
1435         init_completion(&ffs->ep0req_completion);
1436
1437         /* XXX REVISIT need to update it in some places, or do we? */
1438         ffs->ev.can_stall = 1;
1439
1440         return ffs;
1441 }
1442
1443 static void ffs_data_clear(struct ffs_data *ffs)
1444 {
1445         ENTER();
1446
1447         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags))
1448                 ffs_closed(ffs);
1449
1450         BUG_ON(ffs->gadget);
1451
1452         if (ffs->epfiles)
1453                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1454
1455         kfree(ffs->raw_descs_data);
1456         kfree(ffs->raw_strings);
1457         kfree(ffs->stringtabs);
1458 }
1459
1460 static void ffs_data_reset(struct ffs_data *ffs)
1461 {
1462         ENTER();
1463
1464         ffs_data_clear(ffs);
1465
1466         ffs->epfiles = NULL;
1467         ffs->raw_descs_data = NULL;
1468         ffs->raw_descs = NULL;
1469         ffs->raw_strings = NULL;
1470         ffs->stringtabs = NULL;
1471
1472         ffs->raw_descs_length = 0;
1473         ffs->fs_descs_count = 0;
1474         ffs->hs_descs_count = 0;
1475         ffs->ss_descs_count = 0;
1476
1477         ffs->strings_count = 0;
1478         ffs->interfaces_count = 0;
1479         ffs->eps_count = 0;
1480
1481         ffs->ev.count = 0;
1482
1483         ffs->state = FFS_READ_DESCRIPTORS;
1484         ffs->setup_state = FFS_NO_SETUP;
1485         ffs->flags = 0;
1486 }
1487
1488
1489 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1490 {
1491         struct usb_gadget_strings **lang;
1492         int first_id;
1493
1494         ENTER();
1495
1496         if (WARN_ON(ffs->state != FFS_ACTIVE
1497                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1498                 return -EBADFD;
1499
1500         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1501         if (unlikely(first_id < 0))
1502                 return first_id;
1503
1504         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1505         if (unlikely(!ffs->ep0req))
1506                 return -ENOMEM;
1507         ffs->ep0req->complete = ffs_ep0_complete;
1508         ffs->ep0req->context = ffs;
1509
1510         lang = ffs->stringtabs;
1511         for (lang = ffs->stringtabs; *lang; ++lang) {
1512                 struct usb_string *str = (*lang)->strings;
1513                 int id = first_id;
1514                 for (; str->s; ++id, ++str)
1515                         str->id = id;
1516         }
1517
1518         ffs->gadget = cdev->gadget;
1519         ffs_data_get(ffs);
1520         return 0;
1521 }
1522
1523 static void functionfs_unbind(struct ffs_data *ffs)
1524 {
1525         ENTER();
1526
1527         if (!WARN_ON(!ffs->gadget)) {
1528                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1529                 ffs->ep0req = NULL;
1530                 ffs->gadget = NULL;
1531                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1532                 ffs_data_put(ffs);
1533         }
1534 }
1535
1536 static int ffs_epfiles_create(struct ffs_data *ffs)
1537 {
1538         struct ffs_epfile *epfile, *epfiles;
1539         unsigned i, count;
1540
1541         ENTER();
1542
1543         count = ffs->eps_count;
1544         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1545         if (!epfiles)
1546                 return -ENOMEM;
1547
1548         epfile = epfiles;
1549         for (i = 1; i <= count; ++i, ++epfile) {
1550                 epfile->ffs = ffs;
1551                 mutex_init(&epfile->mutex);
1552                 init_waitqueue_head(&epfile->wait);
1553                 sprintf(epfiles->name, "ep%u",  i);
1554                 if (!unlikely(ffs_sb_create_file(ffs->sb, epfiles->name, epfile,
1555                                                  &ffs_epfile_operations,
1556                                                  &epfile->dentry))) {
1557                         ffs_epfiles_destroy(epfiles, i - 1);
1558                         return -ENOMEM;
1559                 }
1560         }
1561
1562         ffs->epfiles = epfiles;
1563         return 0;
1564 }
1565
1566 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1567 {
1568         struct ffs_epfile *epfile = epfiles;
1569
1570         ENTER();
1571
1572         for (; count; --count, ++epfile) {
1573                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1574                        waitqueue_active(&epfile->wait));
1575                 if (epfile->dentry) {
1576                         d_delete(epfile->dentry);
1577                         dput(epfile->dentry);
1578                         epfile->dentry = NULL;
1579                 }
1580         }
1581
1582         kfree(epfiles);
1583 }
1584
1585
1586 static void ffs_func_eps_disable(struct ffs_function *func)
1587 {
1588         struct ffs_ep *ep         = func->eps;
1589         struct ffs_epfile *epfile = func->ffs->epfiles;
1590         unsigned count            = func->ffs->eps_count;
1591         unsigned long flags;
1592
1593         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1594         do {
1595                 /* pending requests get nuked */
1596                 if (likely(ep->ep))
1597                         usb_ep_disable(ep->ep);
1598                 epfile->ep = NULL;
1599
1600                 ++ep;
1601                 ++epfile;
1602         } while (--count);
1603         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1604 }
1605
1606 static int ffs_func_eps_enable(struct ffs_function *func)
1607 {
1608         struct ffs_data *ffs      = func->ffs;
1609         struct ffs_ep *ep         = func->eps;
1610         struct ffs_epfile *epfile = ffs->epfiles;
1611         unsigned count            = ffs->eps_count;
1612         unsigned long flags;
1613         int ret = 0;
1614
1615         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1616         do {
1617                 struct usb_endpoint_descriptor *ds;
1618                 int desc_idx;
1619
1620                 if (ffs->gadget->speed == USB_SPEED_SUPER)
1621                         desc_idx = 2;
1622                 else if (ffs->gadget->speed == USB_SPEED_HIGH)
1623                         desc_idx = 1;
1624                 else
1625                         desc_idx = 0;
1626
1627                 /* fall-back to lower speed if desc missing for current speed */
1628                 do {
1629                         ds = ep->descs[desc_idx];
1630                 } while (!ds && --desc_idx >= 0);
1631
1632                 if (!ds) {
1633                         ret = -EINVAL;
1634                         break;
1635                 }
1636
1637                 ep->ep->driver_data = ep;
1638                 ep->ep->desc = ds;
1639                 ret = usb_ep_enable(ep->ep);
1640                 if (likely(!ret)) {
1641                         epfile->ep = ep;
1642                         epfile->in = usb_endpoint_dir_in(ds);
1643                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1644                 } else {
1645                         break;
1646                 }
1647
1648                 wake_up(&epfile->wait);
1649
1650                 ++ep;
1651                 ++epfile;
1652         } while (--count);
1653         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1654
1655         return ret;
1656 }
1657
1658
1659 /* Parsing and building descriptors and strings *****************************/
1660
1661 /*
1662  * This validates if data pointed by data is a valid USB descriptor as
1663  * well as record how many interfaces, endpoints and strings are
1664  * required by given configuration.  Returns address after the
1665  * descriptor or NULL if data is invalid.
1666  */
1667
1668 enum ffs_entity_type {
1669         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1670 };
1671
1672 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1673                                    u8 *valuep,
1674                                    struct usb_descriptor_header *desc,
1675                                    void *priv);
1676
1677 static int __must_check ffs_do_desc(char *data, unsigned len,
1678                                     ffs_entity_callback entity, void *priv)
1679 {
1680         struct usb_descriptor_header *_ds = (void *)data;
1681         u8 length;
1682         int ret;
1683
1684         ENTER();
1685
1686         /* At least two bytes are required: length and type */
1687         if (len < 2) {
1688                 pr_vdebug("descriptor too short\n");
1689                 return -EINVAL;
1690         }
1691
1692         /* If we have at least as many bytes as the descriptor takes? */
1693         length = _ds->bLength;
1694         if (len < length) {
1695                 pr_vdebug("descriptor longer then available data\n");
1696                 return -EINVAL;
1697         }
1698
1699 #define __entity_check_INTERFACE(val)  1
1700 #define __entity_check_STRING(val)     (val)
1701 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1702 #define __entity(type, val) do {                                        \
1703                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1704                 if (unlikely(!__entity_check_ ##type(val))) {           \
1705                         pr_vdebug("invalid entity's value\n");          \
1706                         return -EINVAL;                                 \
1707                 }                                                       \
1708                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1709                 if (unlikely(ret < 0)) {                                \
1710                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1711                                  (val), ret);                           \
1712                         return ret;                                     \
1713                 }                                                       \
1714         } while (0)
1715
1716         /* Parse descriptor depending on type. */
1717         switch (_ds->bDescriptorType) {
1718         case USB_DT_DEVICE:
1719         case USB_DT_CONFIG:
1720         case USB_DT_STRING:
1721         case USB_DT_DEVICE_QUALIFIER:
1722                 /* function can't have any of those */
1723                 pr_vdebug("descriptor reserved for gadget: %d\n",
1724                       _ds->bDescriptorType);
1725                 return -EINVAL;
1726
1727         case USB_DT_INTERFACE: {
1728                 struct usb_interface_descriptor *ds = (void *)_ds;
1729                 pr_vdebug("interface descriptor\n");
1730                 if (length != sizeof *ds)
1731                         goto inv_length;
1732
1733                 __entity(INTERFACE, ds->bInterfaceNumber);
1734                 if (ds->iInterface)
1735                         __entity(STRING, ds->iInterface);
1736         }
1737                 break;
1738
1739         case USB_DT_ENDPOINT: {
1740                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1741                 pr_vdebug("endpoint descriptor\n");
1742                 if (length != USB_DT_ENDPOINT_SIZE &&
1743                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1744                         goto inv_length;
1745                 __entity(ENDPOINT, ds->bEndpointAddress);
1746         }
1747                 break;
1748
1749         case HID_DT_HID:
1750                 pr_vdebug("hid descriptor\n");
1751                 if (length != sizeof(struct hid_descriptor))
1752                         goto inv_length;
1753                 break;
1754
1755         case USB_DT_OTG:
1756                 if (length != sizeof(struct usb_otg_descriptor))
1757                         goto inv_length;
1758                 break;
1759
1760         case USB_DT_INTERFACE_ASSOCIATION: {
1761                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1762                 pr_vdebug("interface association descriptor\n");
1763                 if (length != sizeof *ds)
1764                         goto inv_length;
1765                 if (ds->iFunction)
1766                         __entity(STRING, ds->iFunction);
1767         }
1768                 break;
1769
1770         case USB_DT_SS_ENDPOINT_COMP:
1771                 pr_vdebug("EP SS companion descriptor\n");
1772                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
1773                         goto inv_length;
1774                 break;
1775
1776         case USB_DT_OTHER_SPEED_CONFIG:
1777         case USB_DT_INTERFACE_POWER:
1778         case USB_DT_DEBUG:
1779         case USB_DT_SECURITY:
1780         case USB_DT_CS_RADIO_CONTROL:
1781                 /* TODO */
1782                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1783                 return -EINVAL;
1784
1785         default:
1786                 /* We should never be here */
1787                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1788                 return -EINVAL;
1789
1790 inv_length:
1791                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1792                           _ds->bLength, _ds->bDescriptorType);
1793                 return -EINVAL;
1794         }
1795
1796 #undef __entity
1797 #undef __entity_check_DESCRIPTOR
1798 #undef __entity_check_INTERFACE
1799 #undef __entity_check_STRING
1800 #undef __entity_check_ENDPOINT
1801
1802         return length;
1803 }
1804
1805 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1806                                      ffs_entity_callback entity, void *priv)
1807 {
1808         const unsigned _len = len;
1809         unsigned long num = 0;
1810
1811         ENTER();
1812
1813         for (;;) {
1814                 int ret;
1815
1816                 if (num == count)
1817                         data = NULL;
1818
1819                 /* Record "descriptor" entity */
1820                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1821                 if (unlikely(ret < 0)) {
1822                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1823                                  num, ret);
1824                         return ret;
1825                 }
1826
1827                 if (!data)
1828                         return _len - len;
1829
1830                 ret = ffs_do_desc(data, len, entity, priv);
1831                 if (unlikely(ret < 0)) {
1832                         pr_debug("%s returns %d\n", __func__, ret);
1833                         return ret;
1834                 }
1835
1836                 len -= ret;
1837                 data += ret;
1838                 ++num;
1839         }
1840 }
1841
1842 static int __ffs_data_do_entity(enum ffs_entity_type type,
1843                                 u8 *valuep, struct usb_descriptor_header *desc,
1844                                 void *priv)
1845 {
1846         struct ffs_data *ffs = priv;
1847
1848         ENTER();
1849
1850         switch (type) {
1851         case FFS_DESCRIPTOR:
1852                 break;
1853
1854         case FFS_INTERFACE:
1855                 /*
1856                  * Interfaces are indexed from zero so if we
1857                  * encountered interface "n" then there are at least
1858                  * "n+1" interfaces.
1859                  */
1860                 if (*valuep >= ffs->interfaces_count)
1861                         ffs->interfaces_count = *valuep + 1;
1862                 break;
1863
1864         case FFS_STRING:
1865                 /*
1866                  * Strings are indexed from 1 (0 is magic ;) reserved
1867                  * for languages list or some such)
1868                  */
1869                 if (*valuep > ffs->strings_count)
1870                         ffs->strings_count = *valuep;
1871                 break;
1872
1873         case FFS_ENDPOINT:
1874                 /* Endpoints are indexed from 1 as well. */
1875                 if ((*valuep & USB_ENDPOINT_NUMBER_MASK) > ffs->eps_count)
1876                         ffs->eps_count = (*valuep & USB_ENDPOINT_NUMBER_MASK);
1877                 break;
1878         }
1879
1880         return 0;
1881 }
1882
1883 static int __ffs_data_got_descs(struct ffs_data *ffs,
1884                                 char *const _data, size_t len)
1885 {
1886         char *data = _data, *raw_descs;
1887         unsigned counts[3], flags;
1888         int ret = -EINVAL, i;
1889
1890         ENTER();
1891
1892         if (get_unaligned_le32(data + 4) != len)
1893                 goto error;
1894
1895         switch (get_unaligned_le32(data)) {
1896         case FUNCTIONFS_DESCRIPTORS_MAGIC:
1897                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
1898                 data += 8;
1899                 len  -= 8;
1900                 break;
1901         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
1902                 flags = get_unaligned_le32(data + 8);
1903                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
1904                               FUNCTIONFS_HAS_HS_DESC |
1905                               FUNCTIONFS_HAS_SS_DESC)) {
1906                         ret = -ENOSYS;
1907                         goto error;
1908                 }
1909                 data += 12;
1910                 len  -= 12;
1911                 break;
1912         default:
1913                 goto error;
1914         }
1915
1916         /* Read fs_count, hs_count and ss_count (if present) */
1917         for (i = 0; i < 3; ++i) {
1918                 if (!(flags & (1 << i))) {
1919                         counts[i] = 0;
1920                 } else if (len < 4) {
1921                         goto error;
1922                 } else {
1923                         counts[i] = get_unaligned_le32(data);
1924                         data += 4;
1925                         len  -= 4;
1926                 }
1927         }
1928
1929         /* Read descriptors */
1930         raw_descs = data;
1931         for (i = 0; i < 3; ++i) {
1932                 if (!counts[i])
1933                         continue;
1934                 ret = ffs_do_descs(counts[i], data, len,
1935                                    __ffs_data_do_entity, ffs);
1936                 if (ret < 0)
1937                         goto error;
1938                 data += ret;
1939                 len  -= ret;
1940         }
1941
1942         if (raw_descs == data || len) {
1943                 ret = -EINVAL;
1944                 goto error;
1945         }
1946
1947         ffs->raw_descs_data     = _data;
1948         ffs->raw_descs          = raw_descs;
1949         ffs->raw_descs_length   = data - raw_descs;
1950         ffs->fs_descs_count     = counts[0];
1951         ffs->hs_descs_count     = counts[1];
1952         ffs->ss_descs_count     = counts[2];
1953
1954         return 0;
1955
1956 error:
1957         kfree(_data);
1958         return ret;
1959 }
1960
1961 static int __ffs_data_got_strings(struct ffs_data *ffs,
1962                                   char *const _data, size_t len)
1963 {
1964         u32 str_count, needed_count, lang_count;
1965         struct usb_gadget_strings **stringtabs, *t;
1966         struct usb_string *strings, *s;
1967         const char *data = _data;
1968
1969         ENTER();
1970
1971         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
1972                      get_unaligned_le32(data + 4) != len))
1973                 goto error;
1974         str_count  = get_unaligned_le32(data + 8);
1975         lang_count = get_unaligned_le32(data + 12);
1976
1977         /* if one is zero the other must be zero */
1978         if (unlikely(!str_count != !lang_count))
1979                 goto error;
1980
1981         /* Do we have at least as many strings as descriptors need? */
1982         needed_count = ffs->strings_count;
1983         if (unlikely(str_count < needed_count))
1984                 goto error;
1985
1986         /*
1987          * If we don't need any strings just return and free all
1988          * memory.
1989          */
1990         if (!needed_count) {
1991                 kfree(_data);
1992                 return 0;
1993         }
1994
1995         /* Allocate everything in one chunk so there's less maintenance. */
1996         {
1997                 unsigned i = 0;
1998                 vla_group(d);
1999                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2000                         lang_count + 1);
2001                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2002                 vla_item(d, struct usb_string, strings,
2003                         lang_count*(needed_count+1));
2004
2005                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2006
2007                 if (unlikely(!vlabuf)) {
2008                         kfree(_data);
2009                         return -ENOMEM;
2010                 }
2011
2012                 /* Initialize the VLA pointers */
2013                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2014                 t = vla_ptr(vlabuf, d, stringtab);
2015                 i = lang_count;
2016                 do {
2017                         *stringtabs++ = t++;
2018                 } while (--i);
2019                 *stringtabs = NULL;
2020
2021                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2022                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2023                 t = vla_ptr(vlabuf, d, stringtab);
2024                 s = vla_ptr(vlabuf, d, strings);
2025                 strings = s;
2026         }
2027
2028         /* For each language */
2029         data += 16;
2030         len -= 16;
2031
2032         do { /* lang_count > 0 so we can use do-while */
2033                 unsigned needed = needed_count;
2034
2035                 if (unlikely(len < 3))
2036                         goto error_free;
2037                 t->language = get_unaligned_le16(data);
2038                 t->strings  = s;
2039                 ++t;
2040
2041                 data += 2;
2042                 len -= 2;
2043
2044                 /* For each string */
2045                 do { /* str_count > 0 so we can use do-while */
2046                         size_t length = strnlen(data, len);
2047
2048                         if (unlikely(length == len))
2049                                 goto error_free;
2050
2051                         /*
2052                          * User may provide more strings then we need,
2053                          * if that's the case we simply ignore the
2054                          * rest
2055                          */
2056                         if (likely(needed)) {
2057                                 /*
2058                                  * s->id will be set while adding
2059                                  * function to configuration so for
2060                                  * now just leave garbage here.
2061                                  */
2062                                 s->s = data;
2063                                 --needed;
2064                                 ++s;
2065                         }
2066
2067                         data += length + 1;
2068                         len -= length + 1;
2069                 } while (--str_count);
2070
2071                 s->id = 0;   /* terminator */
2072                 s->s = NULL;
2073                 ++s;
2074
2075         } while (--lang_count);
2076
2077         /* Some garbage left? */
2078         if (unlikely(len))
2079                 goto error_free;
2080
2081         /* Done! */
2082         ffs->stringtabs = stringtabs;
2083         ffs->raw_strings = _data;
2084
2085         return 0;
2086
2087 error_free:
2088         kfree(stringtabs);
2089 error:
2090         kfree(_data);
2091         return -EINVAL;
2092 }
2093
2094
2095 /* Events handling and management *******************************************/
2096
2097 static void __ffs_event_add(struct ffs_data *ffs,
2098                             enum usb_functionfs_event_type type)
2099 {
2100         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2101         int neg = 0;
2102
2103         /*
2104          * Abort any unhandled setup
2105          *
2106          * We do not need to worry about some cmpxchg() changing value
2107          * of ffs->setup_state without holding the lock because when
2108          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2109          * the source does nothing.
2110          */
2111         if (ffs->setup_state == FFS_SETUP_PENDING)
2112                 ffs->setup_state = FFS_SETUP_CANCELLED;
2113
2114         switch (type) {
2115         case FUNCTIONFS_RESUME:
2116                 rem_type2 = FUNCTIONFS_SUSPEND;
2117                 /* FALL THROUGH */
2118         case FUNCTIONFS_SUSPEND:
2119         case FUNCTIONFS_SETUP:
2120                 rem_type1 = type;
2121                 /* Discard all similar events */
2122                 break;
2123
2124         case FUNCTIONFS_BIND:
2125         case FUNCTIONFS_UNBIND:
2126         case FUNCTIONFS_DISABLE:
2127         case FUNCTIONFS_ENABLE:
2128                 /* Discard everything other then power management. */
2129                 rem_type1 = FUNCTIONFS_SUSPEND;
2130                 rem_type2 = FUNCTIONFS_RESUME;
2131                 neg = 1;
2132                 break;
2133
2134         default:
2135                 BUG();
2136         }
2137
2138         {
2139                 u8 *ev  = ffs->ev.types, *out = ev;
2140                 unsigned n = ffs->ev.count;
2141                 for (; n; --n, ++ev)
2142                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2143                                 *out++ = *ev;
2144                         else
2145                                 pr_vdebug("purging event %d\n", *ev);
2146                 ffs->ev.count = out - ffs->ev.types;
2147         }
2148
2149         pr_vdebug("adding event %d\n", type);
2150         ffs->ev.types[ffs->ev.count++] = type;
2151         wake_up_locked(&ffs->ev.waitq);
2152 }
2153
2154 static void ffs_event_add(struct ffs_data *ffs,
2155                           enum usb_functionfs_event_type type)
2156 {
2157         unsigned long flags;
2158         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2159         __ffs_event_add(ffs, type);
2160         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2161 }
2162
2163
2164 /* Bind/unbind USB function hooks *******************************************/
2165
2166 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2167                                     struct usb_descriptor_header *desc,
2168                                     void *priv)
2169 {
2170         struct usb_endpoint_descriptor *ds = (void *)desc;
2171         struct ffs_function *func = priv;
2172         struct ffs_ep *ffs_ep;
2173         unsigned ep_desc_id, idx;
2174         static const char *speed_names[] = { "full", "high", "super" };
2175
2176         if (type != FFS_DESCRIPTOR)
2177                 return 0;
2178
2179         /*
2180          * If ss_descriptors is not NULL, we are reading super speed
2181          * descriptors; if hs_descriptors is not NULL, we are reading high
2182          * speed descriptors; otherwise, we are reading full speed
2183          * descriptors.
2184          */
2185         if (func->function.ss_descriptors) {
2186                 ep_desc_id = 2;
2187                 func->function.ss_descriptors[(long)valuep] = desc;
2188         } else if (func->function.hs_descriptors) {
2189                 ep_desc_id = 1;
2190                 func->function.hs_descriptors[(long)valuep] = desc;
2191         } else {
2192                 ep_desc_id = 0;
2193                 func->function.fs_descriptors[(long)valuep]    = desc;
2194         }
2195
2196         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2197                 return 0;
2198
2199         idx = (ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK) - 1;
2200         ffs_ep = func->eps + idx;
2201
2202         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2203                 pr_err("two %sspeed descriptors for EP %d\n",
2204                           speed_names[ep_desc_id],
2205                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2206                 return -EINVAL;
2207         }
2208         ffs_ep->descs[ep_desc_id] = ds;
2209
2210         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2211         if (ffs_ep->ep) {
2212                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2213                 if (!ds->wMaxPacketSize)
2214                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2215         } else {
2216                 struct usb_request *req;
2217                 struct usb_ep *ep;
2218
2219                 pr_vdebug("autoconfig\n");
2220                 ep = usb_ep_autoconfig(func->gadget, ds);
2221                 if (unlikely(!ep))
2222                         return -ENOTSUPP;
2223                 ep->driver_data = func->eps + idx;
2224
2225                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2226                 if (unlikely(!req))
2227                         return -ENOMEM;
2228
2229                 ffs_ep->ep  = ep;
2230                 ffs_ep->req = req;
2231                 func->eps_revmap[ds->bEndpointAddress &
2232                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2233         }
2234         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2235
2236         return 0;
2237 }
2238
2239 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2240                                    struct usb_descriptor_header *desc,
2241                                    void *priv)
2242 {
2243         struct ffs_function *func = priv;
2244         unsigned idx;
2245         u8 newValue;
2246
2247         switch (type) {
2248         default:
2249         case FFS_DESCRIPTOR:
2250                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2251                 return 0;
2252
2253         case FFS_INTERFACE:
2254                 idx = *valuep;
2255                 if (func->interfaces_nums[idx] < 0) {
2256                         int id = usb_interface_id(func->conf, &func->function);
2257                         if (unlikely(id < 0))
2258                                 return id;
2259                         func->interfaces_nums[idx] = id;
2260                 }
2261                 newValue = func->interfaces_nums[idx];
2262                 break;
2263
2264         case FFS_STRING:
2265                 /* String' IDs are allocated when fsf_data is bound to cdev */
2266                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2267                 break;
2268
2269         case FFS_ENDPOINT:
2270                 /*
2271                  * USB_DT_ENDPOINT are handled in
2272                  * __ffs_func_bind_do_descs().
2273                  */
2274                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2275                         return 0;
2276
2277                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2278                 if (unlikely(!func->eps[idx].ep))
2279                         return -EINVAL;
2280
2281                 {
2282                         struct usb_endpoint_descriptor **descs;
2283                         descs = func->eps[idx].descs;
2284                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2285                 }
2286                 break;
2287         }
2288
2289         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2290         *valuep = newValue;
2291         return 0;
2292 }
2293
2294 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2295                                                 struct usb_configuration *c)
2296 {
2297         struct ffs_function *func = ffs_func_from_usb(f);
2298         struct f_fs_opts *ffs_opts =
2299                 container_of(f->fi, struct f_fs_opts, func_inst);
2300         int ret;
2301
2302         ENTER();
2303
2304         /*
2305          * Legacy gadget triggers binding in functionfs_ready_callback,
2306          * which already uses locking; taking the same lock here would
2307          * cause a deadlock.
2308          *
2309          * Configfs-enabled gadgets however do need ffs_dev_lock.
2310          */
2311         if (!ffs_opts->no_configfs)
2312                 ffs_dev_lock();
2313         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2314         func->ffs = ffs_opts->dev->ffs_data;
2315         if (!ffs_opts->no_configfs)
2316                 ffs_dev_unlock();
2317         if (ret)
2318                 return ERR_PTR(ret);
2319
2320         func->conf = c;
2321         func->gadget = c->cdev->gadget;
2322
2323         ffs_data_get(func->ffs);
2324
2325         /*
2326          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2327          * configurations are bound in sequence with list_for_each_entry,
2328          * in each configuration its functions are bound in sequence
2329          * with list_for_each_entry, so we assume no race condition
2330          * with regard to ffs_opts->bound access
2331          */
2332         if (!ffs_opts->refcnt) {
2333                 ret = functionfs_bind(func->ffs, c->cdev);
2334                 if (ret)
2335                         return ERR_PTR(ret);
2336         }
2337         ffs_opts->refcnt++;
2338         func->function.strings = func->ffs->stringtabs;
2339
2340         return ffs_opts;
2341 }
2342
2343 static int _ffs_func_bind(struct usb_configuration *c,
2344                           struct usb_function *f)
2345 {
2346         struct ffs_function *func = ffs_func_from_usb(f);
2347         struct ffs_data *ffs = func->ffs;
2348
2349         const int full = !!func->ffs->fs_descs_count;
2350         const int high = gadget_is_dualspeed(func->gadget) &&
2351                 func->ffs->hs_descs_count;
2352         const int super = gadget_is_superspeed(func->gadget) &&
2353                 func->ffs->ss_descs_count;
2354
2355         int fs_len, hs_len, ret;
2356
2357         /* Make it a single chunk, less management later on */
2358         vla_group(d);
2359         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2360         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2361                 full ? ffs->fs_descs_count + 1 : 0);
2362         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2363                 high ? ffs->hs_descs_count + 1 : 0);
2364         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2365                 super ? ffs->ss_descs_count + 1 : 0);
2366         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2367         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2368         char *vlabuf;
2369
2370         ENTER();
2371
2372         /* Has descriptors only for speeds gadget does not support */
2373         if (unlikely(!(full | high | super)))
2374                 return -ENOTSUPP;
2375
2376         /* Allocate a single chunk, less management later on */
2377         vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2378         if (unlikely(!vlabuf))
2379                 return -ENOMEM;
2380
2381         /* Zero */
2382         memset(vla_ptr(vlabuf, d, eps), 0, d_eps__sz);
2383         /* Copy descriptors  */
2384         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
2385                ffs->raw_descs_length);
2386
2387         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2388         for (ret = ffs->eps_count; ret; --ret) {
2389                 struct ffs_ep *ptr;
2390
2391                 ptr = vla_ptr(vlabuf, d, eps);
2392                 ptr[ret].num = -1;
2393         }
2394
2395         /* Save pointers
2396          * d_eps == vlabuf, func->eps used to kfree vlabuf later
2397         */
2398         func->eps             = vla_ptr(vlabuf, d, eps);
2399         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
2400
2401         /*
2402          * Go through all the endpoint descriptors and allocate
2403          * endpoints first, so that later we can rewrite the endpoint
2404          * numbers without worrying that it may be described later on.
2405          */
2406         if (likely(full)) {
2407                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
2408                 fs_len = ffs_do_descs(ffs->fs_descs_count,
2409                                       vla_ptr(vlabuf, d, raw_descs),
2410                                       d_raw_descs__sz,
2411                                       __ffs_func_bind_do_descs, func);
2412                 if (unlikely(fs_len < 0)) {
2413                         ret = fs_len;
2414                         goto error;
2415                 }
2416         } else {
2417                 fs_len = 0;
2418         }
2419
2420         if (likely(high)) {
2421                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
2422                 hs_len = ffs_do_descs(ffs->hs_descs_count,
2423                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
2424                                       d_raw_descs__sz - fs_len,
2425                                       __ffs_func_bind_do_descs, func);
2426                 if (unlikely(hs_len < 0)) {
2427                         ret = hs_len;
2428                         goto error;
2429                 }
2430         } else {
2431                 hs_len = 0;
2432         }
2433
2434         if (likely(super)) {
2435                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
2436                 ret = ffs_do_descs(ffs->ss_descs_count,
2437                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
2438                                 d_raw_descs__sz - fs_len - hs_len,
2439                                 __ffs_func_bind_do_descs, func);
2440                 if (unlikely(ret < 0))
2441                         goto error;
2442         }
2443
2444         /*
2445          * Now handle interface numbers allocation and interface and
2446          * endpoint numbers rewriting.  We can do that in one go
2447          * now.
2448          */
2449         ret = ffs_do_descs(ffs->fs_descs_count +
2450                            (high ? ffs->hs_descs_count : 0) +
2451                            (super ? ffs->ss_descs_count : 0),
2452                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
2453                            __ffs_func_bind_do_nums, func);
2454         if (unlikely(ret < 0))
2455                 goto error;
2456
2457         /* And we're done */
2458         ffs_event_add(ffs, FUNCTIONFS_BIND);
2459         return 0;
2460
2461 error:
2462         /* XXX Do we need to release all claimed endpoints here? */
2463         return ret;
2464 }
2465
2466 static int ffs_func_bind(struct usb_configuration *c,
2467                          struct usb_function *f)
2468 {
2469         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
2470
2471         if (IS_ERR(ffs_opts))
2472                 return PTR_ERR(ffs_opts);
2473
2474         return _ffs_func_bind(c, f);
2475 }
2476
2477
2478 /* Other USB function hooks *************************************************/
2479
2480 static int ffs_func_set_alt(struct usb_function *f,
2481                             unsigned interface, unsigned alt)
2482 {
2483         struct ffs_function *func = ffs_func_from_usb(f);
2484         struct ffs_data *ffs = func->ffs;
2485         int ret = 0, intf;
2486
2487         if (alt != (unsigned)-1) {
2488                 intf = ffs_func_revmap_intf(func, interface);
2489                 if (unlikely(intf < 0))
2490                         return intf;
2491         }
2492
2493         if (ffs->func)
2494                 ffs_func_eps_disable(ffs->func);
2495
2496         if (ffs->state != FFS_ACTIVE)
2497                 return -ENODEV;
2498
2499         if (alt == (unsigned)-1) {
2500                 ffs->func = NULL;
2501                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2502                 return 0;
2503         }
2504
2505         ffs->func = func;
2506         ret = ffs_func_eps_enable(func);
2507         if (likely(ret >= 0))
2508                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2509         return ret;
2510 }
2511
2512 static void ffs_func_disable(struct usb_function *f)
2513 {
2514         ffs_func_set_alt(f, 0, (unsigned)-1);
2515 }
2516
2517 static int ffs_func_setup(struct usb_function *f,
2518                           const struct usb_ctrlrequest *creq)
2519 {
2520         struct ffs_function *func = ffs_func_from_usb(f);
2521         struct ffs_data *ffs = func->ffs;
2522         unsigned long flags;
2523         int ret;
2524
2525         ENTER();
2526
2527         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2528         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2529         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2530         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
2531         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
2532
2533         /*
2534          * Most requests directed to interface go through here
2535          * (notable exceptions are set/get interface) so we need to
2536          * handle them.  All other either handled by composite or
2537          * passed to usb_configuration->setup() (if one is set).  No
2538          * matter, we will handle requests directed to endpoint here
2539          * as well (as it's straightforward) but what to do with any
2540          * other request?
2541          */
2542         if (ffs->state != FFS_ACTIVE)
2543                 return -ENODEV;
2544
2545         switch (creq->bRequestType & USB_RECIP_MASK) {
2546         case USB_RECIP_INTERFACE:
2547                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
2548                 if (unlikely(ret < 0))
2549                         return ret;
2550                 break;
2551
2552         case USB_RECIP_ENDPOINT:
2553                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
2554                 if (unlikely(ret < 0))
2555                         return ret;
2556                 break;
2557
2558         default:
2559                 return -EOPNOTSUPP;
2560         }
2561
2562         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2563         ffs->ev.setup = *creq;
2564         ffs->ev.setup.wIndex = cpu_to_le16(ret);
2565         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
2566         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2567
2568         return 0;
2569 }
2570
2571 static void ffs_func_suspend(struct usb_function *f)
2572 {
2573         ENTER();
2574         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
2575 }
2576
2577 static void ffs_func_resume(struct usb_function *f)
2578 {
2579         ENTER();
2580         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
2581 }
2582
2583
2584 /* Endpoint and interface numbers reverse mapping ***************************/
2585
2586 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
2587 {
2588         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
2589         return num ? num : -EDOM;
2590 }
2591
2592 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
2593 {
2594         short *nums = func->interfaces_nums;
2595         unsigned count = func->ffs->interfaces_count;
2596
2597         for (; count; --count, ++nums) {
2598                 if (*nums >= 0 && *nums == intf)
2599                         return nums - func->interfaces_nums;
2600         }
2601
2602         return -EDOM;
2603 }
2604
2605
2606 /* Devices management *******************************************************/
2607
2608 static LIST_HEAD(ffs_devices);
2609
2610 static struct ffs_dev *_ffs_do_find_dev(const char *name)
2611 {
2612         struct ffs_dev *dev;
2613
2614         list_for_each_entry(dev, &ffs_devices, entry) {
2615                 if (!dev->name || !name)
2616                         continue;
2617                 if (strcmp(dev->name, name) == 0)
2618                         return dev;
2619         }
2620
2621         return NULL;
2622 }
2623
2624 /*
2625  * ffs_lock must be taken by the caller of this function
2626  */
2627 static struct ffs_dev *_ffs_get_single_dev(void)
2628 {
2629         struct ffs_dev *dev;
2630
2631         if (list_is_singular(&ffs_devices)) {
2632                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
2633                 if (dev->single)
2634                         return dev;
2635         }
2636
2637         return NULL;
2638 }
2639
2640 /*
2641  * ffs_lock must be taken by the caller of this function
2642  */
2643 static struct ffs_dev *_ffs_find_dev(const char *name)
2644 {
2645         struct ffs_dev *dev;
2646
2647         dev = _ffs_get_single_dev();
2648         if (dev)
2649                 return dev;
2650
2651         return _ffs_do_find_dev(name);
2652 }
2653
2654 /* Configfs support *********************************************************/
2655
2656 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
2657 {
2658         return container_of(to_config_group(item), struct f_fs_opts,
2659                             func_inst.group);
2660 }
2661
2662 static void ffs_attr_release(struct config_item *item)
2663 {
2664         struct f_fs_opts *opts = to_ffs_opts(item);
2665
2666         usb_put_function_instance(&opts->func_inst);
2667 }
2668
2669 static struct configfs_item_operations ffs_item_ops = {
2670         .release        = ffs_attr_release,
2671 };
2672
2673 static struct config_item_type ffs_func_type = {
2674         .ct_item_ops    = &ffs_item_ops,
2675         .ct_owner       = THIS_MODULE,
2676 };
2677
2678
2679 /* Function registration interface ******************************************/
2680
2681 static void ffs_free_inst(struct usb_function_instance *f)
2682 {
2683         struct f_fs_opts *opts;
2684
2685         opts = to_f_fs_opts(f);
2686         ffs_dev_lock();
2687         _ffs_free_dev(opts->dev);
2688         ffs_dev_unlock();
2689         kfree(opts);
2690 }
2691
2692 #define MAX_INST_NAME_LEN       40
2693
2694 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
2695 {
2696         struct f_fs_opts *opts;
2697         char *ptr;
2698         const char *tmp;
2699         int name_len, ret;
2700
2701         name_len = strlen(name) + 1;
2702         if (name_len > MAX_INST_NAME_LEN)
2703                 return -ENAMETOOLONG;
2704
2705         ptr = kstrndup(name, name_len, GFP_KERNEL);
2706         if (!ptr)
2707                 return -ENOMEM;
2708
2709         opts = to_f_fs_opts(fi);
2710         tmp = NULL;
2711
2712         ffs_dev_lock();
2713
2714         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
2715         ret = _ffs_name_dev(opts->dev, ptr);
2716         if (ret) {
2717                 kfree(ptr);
2718                 ffs_dev_unlock();
2719                 return ret;
2720         }
2721         opts->dev->name_allocated = true;
2722
2723         ffs_dev_unlock();
2724
2725         kfree(tmp);
2726
2727         return 0;
2728 }
2729
2730 static struct usb_function_instance *ffs_alloc_inst(void)
2731 {
2732         struct f_fs_opts *opts;
2733         struct ffs_dev *dev;
2734
2735         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
2736         if (!opts)
2737                 return ERR_PTR(-ENOMEM);
2738
2739         opts->func_inst.set_inst_name = ffs_set_inst_name;
2740         opts->func_inst.free_func_inst = ffs_free_inst;
2741         ffs_dev_lock();
2742         dev = _ffs_alloc_dev();
2743         ffs_dev_unlock();
2744         if (IS_ERR(dev)) {
2745                 kfree(opts);
2746                 return ERR_CAST(dev);
2747         }
2748         opts->dev = dev;
2749         dev->opts = opts;
2750
2751         config_group_init_type_name(&opts->func_inst.group, "",
2752                                     &ffs_func_type);
2753         return &opts->func_inst;
2754 }
2755
2756 static void ffs_free(struct usb_function *f)
2757 {
2758         kfree(ffs_func_from_usb(f));
2759 }
2760
2761 static void ffs_func_unbind(struct usb_configuration *c,
2762                             struct usb_function *f)
2763 {
2764         struct ffs_function *func = ffs_func_from_usb(f);
2765         struct ffs_data *ffs = func->ffs;
2766         struct f_fs_opts *opts =
2767                 container_of(f->fi, struct f_fs_opts, func_inst);
2768         struct ffs_ep *ep = func->eps;
2769         unsigned count = ffs->eps_count;
2770         unsigned long flags;
2771
2772         ENTER();
2773         if (ffs->func == func) {
2774                 ffs_func_eps_disable(func);
2775                 ffs->func = NULL;
2776         }
2777
2778         if (!--opts->refcnt)
2779                 functionfs_unbind(ffs);
2780
2781         /* cleanup after autoconfig */
2782         spin_lock_irqsave(&func->ffs->eps_lock, flags);
2783         do {
2784                 if (ep->ep && ep->req)
2785                         usb_ep_free_request(ep->ep, ep->req);
2786                 ep->req = NULL;
2787                 ++ep;
2788         } while (--count);
2789         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2790         kfree(func->eps);
2791         func->eps = NULL;
2792         /*
2793          * eps, descriptors and interfaces_nums are allocated in the
2794          * same chunk so only one free is required.
2795          */
2796         func->function.fs_descriptors = NULL;
2797         func->function.hs_descriptors = NULL;
2798         func->function.ss_descriptors = NULL;
2799         func->interfaces_nums = NULL;
2800
2801         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
2802 }
2803
2804 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
2805 {
2806         struct ffs_function *func;
2807
2808         ENTER();
2809
2810         func = kzalloc(sizeof(*func), GFP_KERNEL);
2811         if (unlikely(!func))
2812                 return ERR_PTR(-ENOMEM);
2813
2814         func->function.name    = "Function FS Gadget";
2815
2816         func->function.bind    = ffs_func_bind;
2817         func->function.unbind  = ffs_func_unbind;
2818         func->function.set_alt = ffs_func_set_alt;
2819         func->function.disable = ffs_func_disable;
2820         func->function.setup   = ffs_func_setup;
2821         func->function.suspend = ffs_func_suspend;
2822         func->function.resume  = ffs_func_resume;
2823         func->function.free_func = ffs_free;
2824
2825         return &func->function;
2826 }
2827
2828 /*
2829  * ffs_lock must be taken by the caller of this function
2830  */
2831 static struct ffs_dev *_ffs_alloc_dev(void)
2832 {
2833         struct ffs_dev *dev;
2834         int ret;
2835
2836         if (_ffs_get_single_dev())
2837                         return ERR_PTR(-EBUSY);
2838
2839         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2840         if (!dev)
2841                 return ERR_PTR(-ENOMEM);
2842
2843         if (list_empty(&ffs_devices)) {
2844                 ret = functionfs_init();
2845                 if (ret) {
2846                         kfree(dev);
2847                         return ERR_PTR(ret);
2848                 }
2849         }
2850
2851         list_add(&dev->entry, &ffs_devices);
2852
2853         return dev;
2854 }
2855
2856 /*
2857  * ffs_lock must be taken by the caller of this function
2858  * The caller is responsible for "name" being available whenever f_fs needs it
2859  */
2860 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
2861 {
2862         struct ffs_dev *existing;
2863
2864         existing = _ffs_do_find_dev(name);
2865         if (existing)
2866                 return -EBUSY;
2867
2868         dev->name = name;
2869
2870         return 0;
2871 }
2872
2873 /*
2874  * The caller is responsible for "name" being available whenever f_fs needs it
2875  */
2876 int ffs_name_dev(struct ffs_dev *dev, const char *name)
2877 {
2878         int ret;
2879
2880         ffs_dev_lock();
2881         ret = _ffs_name_dev(dev, name);
2882         ffs_dev_unlock();
2883
2884         return ret;
2885 }
2886 EXPORT_SYMBOL(ffs_name_dev);
2887
2888 int ffs_single_dev(struct ffs_dev *dev)
2889 {
2890         int ret;
2891
2892         ret = 0;
2893         ffs_dev_lock();
2894
2895         if (!list_is_singular(&ffs_devices))
2896                 ret = -EBUSY;
2897         else
2898                 dev->single = true;
2899
2900         ffs_dev_unlock();
2901         return ret;
2902 }
2903 EXPORT_SYMBOL(ffs_single_dev);
2904
2905 /*
2906  * ffs_lock must be taken by the caller of this function
2907  */
2908 static void _ffs_free_dev(struct ffs_dev *dev)
2909 {
2910         list_del(&dev->entry);
2911         if (dev->name_allocated)
2912                 kfree(dev->name);
2913         kfree(dev);
2914         if (list_empty(&ffs_devices))
2915                 functionfs_cleanup();
2916 }
2917
2918 static void *ffs_acquire_dev(const char *dev_name)
2919 {
2920         struct ffs_dev *ffs_dev;
2921
2922         ENTER();
2923         ffs_dev_lock();
2924
2925         ffs_dev = _ffs_find_dev(dev_name);
2926         if (!ffs_dev)
2927                 ffs_dev = ERR_PTR(-ENODEV);
2928         else if (ffs_dev->mounted)
2929                 ffs_dev = ERR_PTR(-EBUSY);
2930         else if (ffs_dev->ffs_acquire_dev_callback &&
2931             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
2932                 ffs_dev = ERR_PTR(-ENODEV);
2933         else
2934                 ffs_dev->mounted = true;
2935
2936         ffs_dev_unlock();
2937         return ffs_dev;
2938 }
2939
2940 static void ffs_release_dev(struct ffs_data *ffs_data)
2941 {
2942         struct ffs_dev *ffs_dev;
2943
2944         ENTER();
2945         ffs_dev_lock();
2946
2947         ffs_dev = ffs_data->private_data;
2948         if (ffs_dev) {
2949                 ffs_dev->mounted = false;
2950
2951                 if (ffs_dev->ffs_release_dev_callback)
2952                         ffs_dev->ffs_release_dev_callback(ffs_dev);
2953         }
2954
2955         ffs_dev_unlock();
2956 }
2957
2958 static int ffs_ready(struct ffs_data *ffs)
2959 {
2960         struct ffs_dev *ffs_obj;
2961         int ret = 0;
2962
2963         ENTER();
2964         ffs_dev_lock();
2965
2966         ffs_obj = ffs->private_data;
2967         if (!ffs_obj) {
2968                 ret = -EINVAL;
2969                 goto done;
2970         }
2971         if (WARN_ON(ffs_obj->desc_ready)) {
2972                 ret = -EBUSY;
2973                 goto done;
2974         }
2975
2976         ffs_obj->desc_ready = true;
2977         ffs_obj->ffs_data = ffs;
2978
2979         if (ffs_obj->ffs_ready_callback)
2980                 ret = ffs_obj->ffs_ready_callback(ffs);
2981
2982 done:
2983         ffs_dev_unlock();
2984         return ret;
2985 }
2986
2987 static void ffs_closed(struct ffs_data *ffs)
2988 {
2989         struct ffs_dev *ffs_obj;
2990
2991         ENTER();
2992         ffs_dev_lock();
2993
2994         ffs_obj = ffs->private_data;
2995         if (!ffs_obj)
2996                 goto done;
2997
2998         ffs_obj->desc_ready = false;
2999
3000         if (ffs_obj->ffs_closed_callback)
3001                 ffs_obj->ffs_closed_callback(ffs);
3002
3003         if (!ffs_obj->opts || ffs_obj->opts->no_configfs
3004             || !ffs_obj->opts->func_inst.group.cg_item.ci_parent)
3005                 goto done;
3006
3007         unregister_gadget_item(ffs_obj->opts->
3008                                func_inst.group.cg_item.ci_parent->ci_parent);
3009 done:
3010         ffs_dev_unlock();
3011 }
3012
3013 /* Misc helper functions ****************************************************/
3014
3015 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3016 {
3017         return nonblock
3018                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3019                 : mutex_lock_interruptible(mutex);
3020 }
3021
3022 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3023 {
3024         char *data;
3025
3026         if (unlikely(!len))
3027                 return NULL;
3028
3029         data = kmalloc(len, GFP_KERNEL);
3030         if (unlikely(!data))
3031                 return ERR_PTR(-ENOMEM);
3032
3033         if (unlikely(__copy_from_user(data, buf, len))) {
3034                 kfree(data);
3035                 return ERR_PTR(-EFAULT);
3036         }
3037
3038         pr_vdebug("Buffer from user space:\n");
3039         ffs_dump_mem("", data, len);
3040
3041         return data;
3042 }
3043
3044 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3045 MODULE_LICENSE("GPL");
3046 MODULE_AUTHOR("Michal Nazarewicz");