drivers/usb/gadget/f_fs.c

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