drivers/usb/gadget/function/f_fs.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_fs.c -- user mode file system API for USB composite function controllers
   4  *
   5  * Copyright (C) 2010 Samsung Electronics
   6  * Author: Michal Nazarewicz <mina86@mina86.com>
   7  *
   8  * Based on inode.c (GadgetFS) which was:
   9  * Copyright (C) 2003-2004 David Brownell
  10  * Copyright (C) 2003 Agilent Technologies
  11  */
  12
  13
  14 /* #define DEBUG */
  15 /* #define VERBOSE_DEBUG */
  16
  17 #include <linux/blkdev.h>
  18 #include <linux/dma-buf.h>
  19 #include <linux/dma-fence.h>
  20 #include <linux/dma-resv.h>
  21 #include <linux/pagemap.h>
  22 #include <linux/export.h>
  23 #include <linux/fs_parser.h>
  24 #include <linux/hid.h>
  25 #include <linux/mm.h>
  26 #include <linux/module.h>
  27 #include <linux/scatterlist.h>
  28 #include <linux/sched/signal.h>
  29 #include <linux/uio.h>
  30 #include <linux/vmalloc.h>
  31 #include <asm/unaligned.h>
  32
  33 #include <linux/usb/ccid.h>
  34 #include <linux/usb/composite.h>
  35 #include <linux/usb/functionfs.h>
  36
  37 #include <linux/aio.h>
  38 #include <linux/kthread.h>
  39 #include <linux/poll.h>
  40 #include <linux/eventfd.h>
  41
  42 #include "u_fs.h"
  43 #include "u_f.h"
  44 #include "u_os_desc.h"
  45 #include "configfs.h"
  46
  47 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  48 #define MAX_ALT_SETTINGS        2                 /* Allow up to 2 alt settings to be set. */
  49
  50 #define DMABUF_ENQUEUE_TIMEOUT_MS 5000
  51
  52 MODULE_IMPORT_NS(DMA_BUF);
  53
  54 /* Reference counter handling */
  55 static void ffs_data_get(struct ffs_data *ffs);
  56 static void ffs_data_put(struct ffs_data *ffs);
  57 /* Creates new ffs_data object. */
  58 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  59         __attribute__((malloc));
  60
  61 /* Opened counter handling. */
  62 static void ffs_data_opened(struct ffs_data *ffs);
  63 static void ffs_data_closed(struct ffs_data *ffs);
  64
  65 /* Called with ffs->mutex held; take over ownership of data. */
  66 static int __must_check
  67 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  68 static int __must_check
  69 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  70
  71
  72 /* The function structure ***************************************************/
  73
  74 struct ffs_ep;
  75
  76 struct ffs_function {
  77         struct usb_configuration        *conf;
  78         struct usb_gadget               *gadget;
  79         struct ffs_data                 *ffs;
  80
  81         struct ffs_ep                   *eps;
  82         u8                              eps_revmap[16];
  83         short                           *interfaces_nums;
  84
  85         struct usb_function             function;
  86         int                             cur_alt[MAX_CONFIG_INTERFACES];
  87 };
  88
  89
  90 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  91 {
  92         return container_of(f, struct ffs_function, function);
  93 }
  94
  95
  96 static inline enum ffs_setup_state
  97 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  98 {
  99         return (enum ffs_setup_state)
 100                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
 101 }
 102
 103
 104 static void ffs_func_eps_disable(struct ffs_function *func);
 105 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
 106
 107 static int ffs_func_bind(struct usb_configuration *,
 108                          struct usb_function *);
 109 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 110 static int ffs_func_get_alt(struct usb_function *f, unsigned int intf);
 111 static void ffs_func_disable(struct usb_function *);
 112 static int ffs_func_setup(struct usb_function *,
 113                           const struct usb_ctrlrequest *);
 114 static bool ffs_func_req_match(struct usb_function *,
 115                                const struct usb_ctrlrequest *,
 116                                bool config0);
 117 static void ffs_func_suspend(struct usb_function *);
 118 static void ffs_func_resume(struct usb_function *);
 119
 120
 121 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 122 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 123
 124
 125 /* The endpoints structures *************************************************/
 126
 127 struct ffs_ep {
 128         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 129         struct usb_request              *req;   /* P: epfile->mutex */
 130
 131         /* [0]: full speed, [1]: high speed, [2]: super speed */
 132         struct usb_endpoint_descriptor  *descs[3];
 133
 134         u8                              num;
 135 };
 136
 137 struct ffs_dmabuf_priv {
 138         struct list_head entry;
 139         struct kref ref;
 140         struct ffs_data *ffs;
 141         struct dma_buf_attachment *attach;
 142         struct sg_table *sgt;
 143         enum dma_data_direction dir;
 144         spinlock_t lock;
 145         u64 context;
 146         struct usb_request *req;        /* P: ffs->eps_lock */
 147         struct usb_ep *ep;              /* P: ffs->eps_lock */
 148 };
 149
 150 struct ffs_dma_fence {
 151         struct dma_fence base;
 152         struct ffs_dmabuf_priv *priv;
 153         struct work_struct work;
 154 };
 155
 156 struct ffs_epfile {
 157         /* Protects ep->ep and ep->req. */
 158         struct mutex                    mutex;
 159
 160         struct ffs_data                 *ffs;
 161         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 162
 163         struct dentry                   *dentry;
 164
 165         /*
 166          * Buffer for holding data from partial reads which may happen since
 167          * we’re rounding user read requests to a multiple of a max packet size.
 168          *
 169          * The pointer is initialised with NULL value and may be set by
 170          * __ffs_epfile_read_data function to point to a temporary buffer.
 171          *
 172          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 173          * data from said buffer and eventually free it.  Importantly, while the
 174          * function is using the buffer, it sets the pointer to NULL.  This is
 175          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 176          * can never run concurrently (they are synchronised by epfile->mutex)
 177          * so the latter will not assign a new value to the pointer.
 178          *
 179          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 180          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 181          * value is crux of the synchronisation between ffs_func_eps_disable and
 182          * __ffs_epfile_read_data.
 183          *
 184          * Once __ffs_epfile_read_data is about to finish it will try to set the
 185          * pointer back to its old value (as described above), but seeing as the
 186          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 187          * the buffer.
 188          *
 189          * == State transitions ==
 190          *
 191          * • ptr == NULL:  (initial state)
 192          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 193          *   ◦ __ffs_epfile_read_buffered:    nop
 194          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 195          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 196          * • ptr == DROP:
 197          *   ◦ __ffs_epfile_read_buffer_free: nop
 198          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 199          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 200          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 201          * • ptr == buf:
 202          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 203          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 204          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 205          *                                    is always called first
 206          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 207          * • ptr == NULL and reading:
 208          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 209          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 210          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 211          *   ◦ reading finishes and …
 212          *     … all data read:               free buf, go to ptr == NULL
 213          *     … otherwise:                   go to ptr == buf and reading
 214          * • ptr == DROP and reading:
 215          *   ◦ __ffs_epfile_read_buffer_free: nop
 216          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 217          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 218          *   ◦ reading finishes:              free buf, go to ptr == DROP
 219          */
 220         struct ffs_buffer               *read_buffer;
 221 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 222
 223         char                            name[5];
 224
 225         unsigned char                   in;     /* P: ffs->eps_lock */
 226         unsigned char                   isoc;   /* P: ffs->eps_lock */
 227
 228         unsigned char                   _pad;
 229
 230         /* Protects dmabufs */
 231         struct mutex                    dmabufs_mutex;
 232         struct list_head                dmabufs; /* P: dmabufs_mutex */
 233         atomic_t                        seqno;
 234 };
 235
 236 struct ffs_buffer {
 237         size_t length;
 238         char *data;
 239         char storage[] __counted_by(length);
 240 };
 241
 242 /*  ffs_io_data structure ***************************************************/
 243
 244 struct ffs_io_data {
 245         bool aio;
 246         bool read;
 247
 248         struct kiocb *kiocb;
 249         struct iov_iter data;
 250         const void *to_free;
 251         char *buf;
 252
 253         struct mm_struct *mm;
 254         struct work_struct work;
 255
 256         struct usb_ep *ep;
 257         struct usb_request *req;
 258         struct sg_table sgt;
 259         bool use_sg;
 260
 261         struct ffs_data *ffs;
 262
 263         int status;
 264         struct completion done;
 265 };
 266
 267 struct ffs_desc_helper {
 268         struct ffs_data *ffs;
 269         unsigned interfaces_count;
 270         unsigned eps_count;
 271 };
 272
 273 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 274 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 275
 276 static struct dentry *
 277 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 278                    const struct file_operations *fops);
 279
 280 /* Devices management *******************************************************/
 281
 282 DEFINE_MUTEX(ffs_lock);
 283 EXPORT_SYMBOL_GPL(ffs_lock);
 284
 285 static struct ffs_dev *_ffs_find_dev(const char *name);
 286 static struct ffs_dev *_ffs_alloc_dev(void);
 287 static void _ffs_free_dev(struct ffs_dev *dev);
 288 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data);
 289 static void ffs_release_dev(struct ffs_dev *ffs_dev);
 290 static int ffs_ready(struct ffs_data *ffs);
 291 static void ffs_closed(struct ffs_data *ffs);
 292
 293 /* Misc helper functions ****************************************************/
 294
 295 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 296         __attribute__((warn_unused_result, nonnull));
 297 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 298         __attribute__((warn_unused_result, nonnull));
 299
 300
 301 /* Control file aka ep0 *****************************************************/
 302
 303 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 304 {
 305         struct ffs_data *ffs = req->context;
 306
 307         complete(&ffs->ep0req_completion);
 308 }
 309
 310 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 311         __releases(&ffs->ev.waitq.lock)
 312 {
 313         struct usb_request *req = ffs->ep0req;
 314         int ret;
 315
 316         if (!req) {
 317                 spin_unlock_irq(&ffs->ev.waitq.lock);
 318                 return -EINVAL;
 319         }
 320
 321         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 322
 323         spin_unlock_irq(&ffs->ev.waitq.lock);
 324
 325         req->buf      = data;
 326         req->length   = len;
 327
 328         /*
 329          * UDC layer requires to provide a buffer even for ZLP, but should
 330          * not use it at all. Let's provide some poisoned pointer to catch
 331          * possible bug in the driver.
 332          */
 333         if (req->buf == NULL)
 334                 req->buf = (void *)0xDEADBABE;
 335
 336         reinit_completion(&ffs->ep0req_completion);
 337
 338         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 339         if (ret < 0)
 340                 return ret;
 341
 342         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 343         if (ret) {
 344                 usb_ep_dequeue(ffs->gadget->ep0, req);
 345                 return -EINTR;
 346         }
 347
 348         ffs->setup_state = FFS_NO_SETUP;
 349         return req->status ? req->status : req->actual;
 350 }
 351
 352 static int __ffs_ep0_stall(struct ffs_data *ffs)
 353 {
 354         if (ffs->ev.can_stall) {
 355                 pr_vdebug("ep0 stall\n");
 356                 usb_ep_set_halt(ffs->gadget->ep0);
 357                 ffs->setup_state = FFS_NO_SETUP;
 358                 return -EL2HLT;
 359         } else {
 360                 pr_debug("bogus ep0 stall!\n");
 361                 return -ESRCH;
 362         }
 363 }
 364
 365 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 366                              size_t len, loff_t *ptr)
 367 {
 368         struct ffs_data *ffs = file->private_data;
 369         ssize_t ret;
 370         char *data;
 371
 372         /* Fast check if setup was canceled */
 373         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 374                 return -EIDRM;
 375
 376         /* Acquire mutex */
 377         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 378         if (ret < 0)
 379                 return ret;
 380
 381         /* Check state */
 382         switch (ffs->state) {
 383         case FFS_READ_DESCRIPTORS:
 384         case FFS_READ_STRINGS:
 385                 /* Copy data */
 386                 if (len < 16) {
 387                         ret = -EINVAL;
 388                         break;
 389                 }
 390
 391                 data = ffs_prepare_buffer(buf, len);
 392                 if (IS_ERR(data)) {
 393                         ret = PTR_ERR(data);
 394                         break;
 395                 }
 396
 397                 /* Handle data */
 398                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 399                         pr_info("read descriptors\n");
 400                         ret = __ffs_data_got_descs(ffs, data, len);
 401                         if (ret < 0)
 402                                 break;
 403
 404                         ffs->state = FFS_READ_STRINGS;
 405                         ret = len;
 406                 } else {
 407                         pr_info("read strings\n");
 408                         ret = __ffs_data_got_strings(ffs, data, len);
 409                         if (ret < 0)
 410                                 break;
 411
 412                         ret = ffs_epfiles_create(ffs);
 413                         if (ret) {
 414                                 ffs->state = FFS_CLOSING;
 415                                 break;
 416                         }
 417
 418                         ffs->state = FFS_ACTIVE;
 419                         mutex_unlock(&ffs->mutex);
 420
 421                         ret = ffs_ready(ffs);
 422                         if (ret < 0) {
 423                                 ffs->state = FFS_CLOSING;
 424                                 return ret;
 425                         }
 426
 427                         return len;
 428                 }
 429                 break;
 430
 431         case FFS_ACTIVE:
 432                 data = NULL;
 433                 /*
 434                  * We're called from user space, we can use _irq
 435                  * rather then _irqsave
 436                  */
 437                 spin_lock_irq(&ffs->ev.waitq.lock);
 438                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 439                 case FFS_SETUP_CANCELLED:
 440                         ret = -EIDRM;
 441                         goto done_spin;
 442
 443                 case FFS_NO_SETUP:
 444                         ret = -ESRCH;
 445                         goto done_spin;
 446
 447                 case FFS_SETUP_PENDING:
 448                         break;
 449                 }
 450
 451                 /* FFS_SETUP_PENDING */
 452                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 453                         spin_unlock_irq(&ffs->ev.waitq.lock);
 454                         ret = __ffs_ep0_stall(ffs);
 455                         break;
 456                 }
 457
 458                 /* FFS_SETUP_PENDING and not stall */
 459                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 460
 461                 spin_unlock_irq(&ffs->ev.waitq.lock);
 462
 463                 data = ffs_prepare_buffer(buf, len);
 464                 if (IS_ERR(data)) {
 465                         ret = PTR_ERR(data);
 466                         break;
 467                 }
 468
 469                 spin_lock_irq(&ffs->ev.waitq.lock);
 470
 471                 /*
 472                  * We are guaranteed to be still in FFS_ACTIVE state
 473                  * but the state of setup could have changed from
 474                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 475                  * to check for that.  If that happened we copied data
 476                  * from user space in vain but it's unlikely.
 477                  *
 478                  * For sure we are not in FFS_NO_SETUP since this is
 479                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 480                  * transition can be performed and it's protected by
 481                  * mutex.
 482                  */
 483                 if (ffs_setup_state_clear_cancelled(ffs) ==
 484                     FFS_SETUP_CANCELLED) {
 485                         ret = -EIDRM;
 486 done_spin:
 487                         spin_unlock_irq(&ffs->ev.waitq.lock);
 488                 } else {
 489                         /* unlocks spinlock */
 490                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 491                 }
 492                 kfree(data);
 493                 break;
 494
 495         default:
 496                 ret = -EBADFD;
 497                 break;
 498         }
 499
 500         mutex_unlock(&ffs->mutex);
 501         return ret;
 502 }
 503
 504 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 505 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 506                                      size_t n)
 507         __releases(&ffs->ev.waitq.lock)
 508 {
 509         /*
 510          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 511          * size of ffs->ev.types array (which is four) so that's how much space
 512          * we reserve.
 513          */
 514         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 515         const size_t size = n * sizeof *events;
 516         unsigned i = 0;
 517
 518         memset(events, 0, size);
 519
 520         do {
 521                 events[i].type = ffs->ev.types[i];
 522                 if (events[i].type == FUNCTIONFS_SETUP) {
 523                         events[i].u.setup = ffs->ev.setup;
 524                         ffs->setup_state = FFS_SETUP_PENDING;
 525                 }
 526         } while (++i < n);
 527
 528         ffs->ev.count -= n;
 529         if (ffs->ev.count)
 530                 memmove(ffs->ev.types, ffs->ev.types + n,
 531                         ffs->ev.count * sizeof *ffs->ev.types);
 532
 533         spin_unlock_irq(&ffs->ev.waitq.lock);
 534         mutex_unlock(&ffs->mutex);
 535
 536         return copy_to_user(buf, events, size) ? -EFAULT : size;
 537 }
 538
 539 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 540                             size_t len, loff_t *ptr)
 541 {
 542         struct ffs_data *ffs = file->private_data;
 543         char *data = NULL;
 544         size_t n;
 545         int ret;
 546
 547         /* Fast check if setup was canceled */
 548         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 549                 return -EIDRM;
 550
 551         /* Acquire mutex */
 552         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 553         if (ret < 0)
 554                 return ret;
 555
 556         /* Check state */
 557         if (ffs->state != FFS_ACTIVE) {
 558                 ret = -EBADFD;
 559                 goto done_mutex;
 560         }
 561
 562         /*
 563          * We're called from user space, we can use _irq rather then
 564          * _irqsave
 565          */
 566         spin_lock_irq(&ffs->ev.waitq.lock);
 567
 568         switch (ffs_setup_state_clear_cancelled(ffs)) {
 569         case FFS_SETUP_CANCELLED:
 570                 ret = -EIDRM;
 571                 break;
 572
 573         case FFS_NO_SETUP:
 574                 n = len / sizeof(struct usb_functionfs_event);
 575                 if (!n) {
 576                         ret = -EINVAL;
 577                         break;
 578                 }
 579
 580                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 581                         ret = -EAGAIN;
 582                         break;
 583                 }
 584
 585                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 586                                                         ffs->ev.count)) {
 587                         ret = -EINTR;
 588                         break;
 589                 }
 590
 591                 /* unlocks spinlock */
 592                 return __ffs_ep0_read_events(ffs, buf,
 593                                              min(n, (size_t)ffs->ev.count));
 594
 595         case FFS_SETUP_PENDING:
 596                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 597                         spin_unlock_irq(&ffs->ev.waitq.lock);
 598                         ret = __ffs_ep0_stall(ffs);
 599                         goto done_mutex;
 600                 }
 601
 602                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 603
 604                 spin_unlock_irq(&ffs->ev.waitq.lock);
 605
 606                 if (len) {
 607                         data = kmalloc(len, GFP_KERNEL);
 608                         if (!data) {
 609                                 ret = -ENOMEM;
 610                                 goto done_mutex;
 611                         }
 612                 }
 613
 614                 spin_lock_irq(&ffs->ev.waitq.lock);
 615
 616                 /* See ffs_ep0_write() */
 617                 if (ffs_setup_state_clear_cancelled(ffs) ==
 618                     FFS_SETUP_CANCELLED) {
 619                         ret = -EIDRM;
 620                         break;
 621                 }
 622
 623                 /* unlocks spinlock */
 624                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 625                 if ((ret > 0) && (copy_to_user(buf, data, len)))
 626                         ret = -EFAULT;
 627                 goto done_mutex;
 628
 629         default:
 630                 ret = -EBADFD;
 631                 break;
 632         }
 633
 634         spin_unlock_irq(&ffs->ev.waitq.lock);
 635 done_mutex:
 636         mutex_unlock(&ffs->mutex);
 637         kfree(data);
 638         return ret;
 639 }
 640
 641 static int ffs_ep0_open(struct inode *inode, struct file *file)
 642 {
 643         struct ffs_data *ffs = inode->i_private;
 644
 645         if (ffs->state == FFS_CLOSING)
 646                 return -EBUSY;
 647
 648         file->private_data = ffs;
 649         ffs_data_opened(ffs);
 650
 651         return stream_open(inode, file);
 652 }
 653
 654 static int ffs_ep0_release(struct inode *inode, struct file *file)
 655 {
 656         struct ffs_data *ffs = file->private_data;
 657
 658         ffs_data_closed(ffs);
 659
 660         return 0;
 661 }
 662
 663 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 664 {
 665         struct ffs_data *ffs = file->private_data;
 666         struct usb_gadget *gadget = ffs->gadget;
 667         long ret;
 668
 669         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 670                 struct ffs_function *func = ffs->func;
 671                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 672         } else if (gadget && gadget->ops->ioctl) {
 673                 ret = gadget->ops->ioctl(gadget, code, value);
 674         } else {
 675                 ret = -ENOTTY;
 676         }
 677
 678         return ret;
 679 }
 680
 681 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 682 {
 683         struct ffs_data *ffs = file->private_data;
 684         __poll_t mask = EPOLLWRNORM;
 685         int ret;
 686
 687         poll_wait(file, &ffs->ev.waitq, wait);
 688
 689         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 690         if (ret < 0)
 691                 return mask;
 692
 693         switch (ffs->state) {
 694         case FFS_READ_DESCRIPTORS:
 695         case FFS_READ_STRINGS:
 696                 mask |= EPOLLOUT;
 697                 break;
 698
 699         case FFS_ACTIVE:
 700                 switch (ffs->setup_state) {
 701                 case FFS_NO_SETUP:
 702                         if (ffs->ev.count)
 703                                 mask |= EPOLLIN;
 704                         break;
 705
 706                 case FFS_SETUP_PENDING:
 707                 case FFS_SETUP_CANCELLED:
 708                         mask |= (EPOLLIN | EPOLLOUT);
 709                         break;
 710                 }
 711                 break;
 712
 713         case FFS_CLOSING:
 714                 break;
 715         case FFS_DEACTIVATED:
 716                 break;
 717         }
 718
 719         mutex_unlock(&ffs->mutex);
 720
 721         return mask;
 722 }
 723
 724 static const struct file_operations ffs_ep0_operations = {
 725         .llseek =       no_llseek,
 726
 727         .open =         ffs_ep0_open,
 728         .write =        ffs_ep0_write,
 729         .read =         ffs_ep0_read,
 730         .release =      ffs_ep0_release,
 731         .unlocked_ioctl =       ffs_ep0_ioctl,
 732         .poll =         ffs_ep0_poll,
 733 };
 734
 735
 736 /* "Normal" endpoints operations ********************************************/
 737
 738 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 739 {
 740         struct ffs_io_data *io_data = req->context;
 741
 742         if (req->status)
 743                 io_data->status = req->status;
 744         else
 745                 io_data->status = req->actual;
 746
 747         complete(&io_data->done);
 748 }
 749
 750 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 751 {
 752         ssize_t ret = copy_to_iter(data, data_len, iter);
 753         if (ret == data_len)
 754                 return ret;
 755
 756         if (iov_iter_count(iter))
 757                 return -EFAULT;
 758
 759         /*
 760          * Dear user space developer!
 761          *
 762          * TL;DR: To stop getting below error message in your kernel log, change
 763          * user space code using functionfs to align read buffers to a max
 764          * packet size.
 765          *
 766          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 767          * packet size.  When unaligned buffer is passed to functionfs, it
 768          * internally uses a larger, aligned buffer so that such UDCs are happy.
 769          *
 770          * Unfortunately, this means that host may send more data than was
 771          * requested in read(2) system call.  f_fs doesn’t know what to do with
 772          * that excess data so it simply drops it.
 773          *
 774          * Was the buffer aligned in the first place, no such problem would
 775          * happen.
 776          *
 777          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 778          * by splitting a request into multiple parts.  This splitting may still
 779          * be a problem though so it’s likely best to align the buffer
 780          * regardless of it being AIO or not..
 781          *
 782          * This only affects OUT endpoints, i.e. reading data with a read(2),
 783          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 784          * affected.
 785          */
 786         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 787                "Align read buffer size to max packet size to avoid the problem.\n",
 788                data_len, ret);
 789
 790         return ret;
 791 }
 792
 793 /*
 794  * allocate a virtually contiguous buffer and create a scatterlist describing it
 795  * @sg_table    - pointer to a place to be filled with sg_table contents
 796  * @size        - required buffer size
 797  */
 798 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 799 {
 800         struct page **pages;
 801         void *vaddr, *ptr;
 802         unsigned int n_pages;
 803         int i;
 804
 805         vaddr = vmalloc(sz);
 806         if (!vaddr)
 807                 return NULL;
 808
 809         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 810         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 811         if (!pages) {
 812                 vfree(vaddr);
 813
 814                 return NULL;
 815         }
 816         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 817                 pages[i] = vmalloc_to_page(ptr);
 818
 819         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 820                 kvfree(pages);
 821                 vfree(vaddr);
 822
 823                 return NULL;
 824         }
 825         kvfree(pages);
 826
 827         return vaddr;
 828 }
 829
 830 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 831         size_t data_len)
 832 {
 833         if (io_data->use_sg)
 834                 return ffs_build_sg_list(&io_data->sgt, data_len);
 835
 836         return kmalloc(data_len, GFP_KERNEL);
 837 }
 838
 839 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 840 {
 841         if (!io_data->buf)
 842                 return;
 843
 844         if (io_data->use_sg) {
 845                 sg_free_table(&io_data->sgt);
 846                 vfree(io_data->buf);
 847         } else {
 848                 kfree(io_data->buf);
 849         }
 850 }
 851
 852 static void ffs_user_copy_worker(struct work_struct *work)
 853 {
 854         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 855                                                    work);
 856         int ret = io_data->status;
 857         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 858         unsigned long flags;
 859
 860         if (io_data->read && ret > 0) {
 861                 kthread_use_mm(io_data->mm);
 862                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 863                 kthread_unuse_mm(io_data->mm);
 864         }
 865
 866         io_data->kiocb->ki_complete(io_data->kiocb, ret);
 867
 868         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 869                 eventfd_signal(io_data->ffs->ffs_eventfd);
 870
 871         spin_lock_irqsave(&io_data->ffs->eps_lock, flags);
 872         usb_ep_free_request(io_data->ep, io_data->req);
 873         io_data->req = NULL;
 874         spin_unlock_irqrestore(&io_data->ffs->eps_lock, flags);
 875
 876         if (io_data->read)
 877                 kfree(io_data->to_free);
 878         ffs_free_buffer(io_data);
 879         kfree(io_data);
 880 }
 881
 882 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 883                                          struct usb_request *req)
 884 {
 885         struct ffs_io_data *io_data = req->context;
 886         struct ffs_data *ffs = io_data->ffs;
 887
 888         io_data->status = req->status ? req->status : req->actual;
 889
 890         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 891         queue_work(ffs->io_completion_wq, &io_data->work);
 892 }
 893
 894 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 895 {
 896         /*
 897          * See comment in struct ffs_epfile for full read_buffer pointer
 898          * synchronisation story.
 899          */
 900         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 901         if (buf && buf != READ_BUFFER_DROP)
 902                 kfree(buf);
 903 }
 904
 905 /* Assumes epfile->mutex is held. */
 906 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 907                                           struct iov_iter *iter)
 908 {
 909         /*
 910          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 911          * the buffer while we are using it.  See comment in struct ffs_epfile
 912          * for full read_buffer pointer synchronisation story.
 913          */
 914         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 915         ssize_t ret;
 916         if (!buf || buf == READ_BUFFER_DROP)
 917                 return 0;
 918
 919         ret = copy_to_iter(buf->data, buf->length, iter);
 920         if (buf->length == ret) {
 921                 kfree(buf);
 922                 return ret;
 923         }
 924
 925         if (iov_iter_count(iter)) {
 926                 ret = -EFAULT;
 927         } else {
 928                 buf->length -= ret;
 929                 buf->data += ret;
 930         }
 931
 932         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 933                 kfree(buf);
 934
 935         return ret;
 936 }
 937
 938 /* Assumes epfile->mutex is held. */
 939 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 940                                       void *data, int data_len,
 941                                       struct iov_iter *iter)
 942 {
 943         struct ffs_buffer *buf;
 944
 945         ssize_t ret = copy_to_iter(data, data_len, iter);
 946         if (data_len == ret)
 947                 return ret;
 948
 949         if (iov_iter_count(iter))
 950                 return -EFAULT;
 951
 952         /* See ffs_copy_to_iter for more context. */
 953         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 954                 data_len, ret);
 955
 956         data_len -= ret;
 957         buf = kmalloc(struct_size(buf, storage, data_len), GFP_KERNEL);
 958         if (!buf)
 959                 return -ENOMEM;
 960         buf->length = data_len;
 961         buf->data = buf->storage;
 962         memcpy(buf->storage, data + ret, flex_array_size(buf, storage, data_len));
 963
 964         /*
 965          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 966          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 967          * in struct ffs_epfile for full read_buffer pointer synchronisation
 968          * story.
 969          */
 970         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 971                 kfree(buf);
 972
 973         return ret;
 974 }
 975
 976 static struct ffs_ep *ffs_epfile_wait_ep(struct file *file)
 977 {
 978         struct ffs_epfile *epfile = file->private_data;
 979         struct ffs_ep *ep;
 980         int ret;
 981
 982         /* Wait for endpoint to be enabled */
 983         ep = epfile->ep;
 984         if (!ep) {
 985                 if (file->f_flags & O_NONBLOCK)
 986                         return ERR_PTR(-EAGAIN);
 987
 988                 ret = wait_event_interruptible(
 989                                 epfile->ffs->wait, (ep = epfile->ep));
 990                 if (ret)
 991                         return ERR_PTR(-EINTR);
 992         }
 993
 994         return ep;
 995 }
 996
 997 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 998 {
 999         struct ffs_epfile *epfile = file->private_data;
1000         struct usb_request *req;
1001         struct ffs_ep *ep;
1002         char *data = NULL;
1003         ssize_t ret, data_len = -EINVAL;
1004         int halt;
1005
1006         /* Are we still active? */
1007         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1008                 return -ENODEV;
1009
1010         ep = ffs_epfile_wait_ep(file);
1011         if (IS_ERR(ep))
1012                 return PTR_ERR(ep);
1013
1014         /* Do we halt? */
1015         halt = (!io_data->read == !epfile->in);
1016         if (halt && epfile->isoc)
1017                 return -EINVAL;
1018
1019         /* We will be using request and read_buffer */
1020         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
1021         if (ret)
1022                 goto error;
1023
1024         /* Allocate & copy */
1025         if (!halt) {
1026                 struct usb_gadget *gadget;
1027
1028                 /*
1029                  * Do we have buffered data from previous partial read?  Check
1030                  * that for synchronous case only because we do not have
1031                  * facility to ‘wake up’ a pending asynchronous read and push
1032                  * buffered data to it which we would need to make things behave
1033                  * consistently.
1034                  */
1035                 if (!io_data->aio && io_data->read) {
1036                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
1037                         if (ret)
1038                                 goto error_mutex;
1039                 }
1040
1041                 /*
1042                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
1043                  * before the waiting completes, so do not assign to 'gadget'
1044                  * earlier
1045                  */
1046                 gadget = epfile->ffs->gadget;
1047
1048                 spin_lock_irq(&epfile->ffs->eps_lock);
1049                 /* In the meantime, endpoint got disabled or changed. */
1050                 if (epfile->ep != ep) {
1051                         ret = -ESHUTDOWN;
1052                         goto error_lock;
1053                 }
1054                 data_len = iov_iter_count(&io_data->data);
1055                 /*
1056                  * Controller may require buffer size to be aligned to
1057                  * maxpacketsize of an out endpoint.
1058                  */
1059                 if (io_data->read)
1060                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1061
1062                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1063                 spin_unlock_irq(&epfile->ffs->eps_lock);
1064
1065                 data = ffs_alloc_buffer(io_data, data_len);
1066                 if (!data) {
1067                         ret = -ENOMEM;
1068                         goto error_mutex;
1069                 }
1070                 if (!io_data->read &&
1071                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1072                         ret = -EFAULT;
1073                         goto error_mutex;
1074                 }
1075         }
1076
1077         spin_lock_irq(&epfile->ffs->eps_lock);
1078
1079         if (epfile->ep != ep) {
1080                 /* In the meantime, endpoint got disabled or changed. */
1081                 ret = -ESHUTDOWN;
1082         } else if (halt) {
1083                 ret = usb_ep_set_halt(ep->ep);
1084                 if (!ret)
1085                         ret = -EBADMSG;
1086         } else if (data_len == -EINVAL) {
1087                 /*
1088                  * Sanity Check: even though data_len can't be used
1089                  * uninitialized at the time I write this comment, some
1090                  * compilers complain about this situation.
1091                  * In order to keep the code clean from warnings, data_len is
1092                  * being initialized to -EINVAL during its declaration, which
1093                  * means we can't rely on compiler anymore to warn no future
1094                  * changes won't result in data_len being used uninitialized.
1095                  * For such reason, we're adding this redundant sanity check
1096                  * here.
1097                  */
1098                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1099                 ret = -EINVAL;
1100         } else if (!io_data->aio) {
1101                 bool interrupted = false;
1102
1103                 req = ep->req;
1104                 if (io_data->use_sg) {
1105                         req->buf = NULL;
1106                         req->sg = io_data->sgt.sgl;
1107                         req->num_sgs = io_data->sgt.nents;
1108                 } else {
1109                         req->buf = data;
1110                         req->num_sgs = 0;
1111                 }
1112                 req->length = data_len;
1113
1114                 io_data->buf = data;
1115
1116                 init_completion(&io_data->done);
1117                 req->context  = io_data;
1118                 req->complete = ffs_epfile_io_complete;
1119
1120                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1121                 if (ret < 0)
1122                         goto error_lock;
1123
1124                 spin_unlock_irq(&epfile->ffs->eps_lock);
1125
1126                 if (wait_for_completion_interruptible(&io_data->done)) {
1127                         spin_lock_irq(&epfile->ffs->eps_lock);
1128                         if (epfile->ep != ep) {
1129                                 ret = -ESHUTDOWN;
1130                                 goto error_lock;
1131                         }
1132                         /*
1133                          * To avoid race condition with ffs_epfile_io_complete,
1134                          * dequeue the request first then check
1135                          * status. usb_ep_dequeue API should guarantee no race
1136                          * condition with req->complete callback.
1137                          */
1138                         usb_ep_dequeue(ep->ep, req);
1139                         spin_unlock_irq(&epfile->ffs->eps_lock);
1140                         wait_for_completion(&io_data->done);
1141                         interrupted = io_data->status < 0;
1142                 }
1143
1144                 if (interrupted)
1145                         ret = -EINTR;
1146                 else if (io_data->read && io_data->status > 0)
1147                         ret = __ffs_epfile_read_data(epfile, data, io_data->status,
1148                                                      &io_data->data);
1149                 else
1150                         ret = io_data->status;
1151                 goto error_mutex;
1152         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1153                 ret = -ENOMEM;
1154         } else {
1155                 if (io_data->use_sg) {
1156                         req->buf = NULL;
1157                         req->sg = io_data->sgt.sgl;
1158                         req->num_sgs = io_data->sgt.nents;
1159                 } else {
1160                         req->buf = data;
1161                         req->num_sgs = 0;
1162                 }
1163                 req->length = data_len;
1164
1165                 io_data->buf = data;
1166                 io_data->ep = ep->ep;
1167                 io_data->req = req;
1168                 io_data->ffs = epfile->ffs;
1169
1170                 req->context  = io_data;
1171                 req->complete = ffs_epfile_async_io_complete;
1172
1173                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1174                 if (ret) {
1175                         io_data->req = NULL;
1176                         usb_ep_free_request(ep->ep, req);
1177                         goto error_lock;
1178                 }
1179
1180                 ret = -EIOCBQUEUED;
1181                 /*
1182                  * Do not kfree the buffer in this function.  It will be freed
1183                  * by ffs_user_copy_worker.
1184                  */
1185                 data = NULL;
1186         }
1187
1188 error_lock:
1189         spin_unlock_irq(&epfile->ffs->eps_lock);
1190 error_mutex:
1191         mutex_unlock(&epfile->mutex);
1192 error:
1193         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1194                 ffs_free_buffer(io_data);
1195         return ret;
1196 }
1197
1198 static int
1199 ffs_epfile_open(struct inode *inode, struct file *file)
1200 {
1201         struct ffs_epfile *epfile = inode->i_private;
1202
1203         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1204                 return -ENODEV;
1205
1206         file->private_data = epfile;
1207         ffs_data_opened(epfile->ffs);
1208
1209         return stream_open(inode, file);
1210 }
1211
1212 static int ffs_aio_cancel(struct kiocb *kiocb)
1213 {
1214         struct ffs_io_data *io_data = kiocb->private;
1215         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1216         unsigned long flags;
1217         int value;
1218
1219         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1220
1221         if (io_data && io_data->ep && io_data->req)
1222                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1223         else
1224                 value = -EINVAL;
1225
1226         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1227
1228         return value;
1229 }
1230
1231 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1232 {
1233         struct ffs_io_data io_data, *p = &io_data;
1234         ssize_t res;
1235
1236         if (!is_sync_kiocb(kiocb)) {
1237                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1238                 if (!p)
1239                         return -ENOMEM;
1240                 p->aio = true;
1241         } else {
1242                 memset(p, 0, sizeof(*p));
1243                 p->aio = false;
1244         }
1245
1246         p->read = false;
1247         p->kiocb = kiocb;
1248         p->data = *from;
1249         p->mm = current->mm;
1250
1251         kiocb->private = p;
1252
1253         if (p->aio)
1254                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1255
1256         res = ffs_epfile_io(kiocb->ki_filp, p);
1257         if (res == -EIOCBQUEUED)
1258                 return res;
1259         if (p->aio)
1260                 kfree(p);
1261         else
1262                 *from = p->data;
1263         return res;
1264 }
1265
1266 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1267 {
1268         struct ffs_io_data io_data, *p = &io_data;
1269         ssize_t res;
1270
1271         if (!is_sync_kiocb(kiocb)) {
1272                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1273                 if (!p)
1274                         return -ENOMEM;
1275                 p->aio = true;
1276         } else {
1277                 memset(p, 0, sizeof(*p));
1278                 p->aio = false;
1279         }
1280
1281         p->read = true;
1282         p->kiocb = kiocb;
1283         if (p->aio) {
1284                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1285                 if (!iter_is_ubuf(&p->data) && !p->to_free) {
1286                         kfree(p);
1287                         return -ENOMEM;
1288                 }
1289         } else {
1290                 p->data = *to;
1291                 p->to_free = NULL;
1292         }
1293         p->mm = current->mm;
1294
1295         kiocb->private = p;
1296
1297         if (p->aio)
1298                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1299
1300         res = ffs_epfile_io(kiocb->ki_filp, p);
1301         if (res == -EIOCBQUEUED)
1302                 return res;
1303
1304         if (p->aio) {
1305                 kfree(p->to_free);
1306                 kfree(p);
1307         } else {
1308                 *to = p->data;
1309         }
1310         return res;
1311 }
1312
1313 static void ffs_dmabuf_release(struct kref *ref)
1314 {
1315         struct ffs_dmabuf_priv *priv = container_of(ref, struct ffs_dmabuf_priv, ref);
1316         struct dma_buf_attachment *attach = priv->attach;
1317         struct dma_buf *dmabuf = attach->dmabuf;
1318
1319         pr_vdebug("FFS DMABUF release\n");
1320         dma_resv_lock(dmabuf->resv, NULL);
1321         dma_buf_unmap_attachment(attach, priv->sgt, priv->dir);
1322         dma_resv_unlock(dmabuf->resv);
1323
1324         dma_buf_detach(attach->dmabuf, attach);
1325         dma_buf_put(dmabuf);
1326         kfree(priv);
1327 }
1328
1329 static void ffs_dmabuf_get(struct dma_buf_attachment *attach)
1330 {
1331         struct ffs_dmabuf_priv *priv = attach->importer_priv;
1332
1333         kref_get(&priv->ref);
1334 }
1335
1336 static void ffs_dmabuf_put(struct dma_buf_attachment *attach)
1337 {
1338         struct ffs_dmabuf_priv *priv = attach->importer_priv;
1339
1340         kref_put(&priv->ref, ffs_dmabuf_release);
1341 }
1342
1343 static int
1344 ffs_epfile_release(struct inode *inode, struct file *file)
1345 {
1346         struct ffs_epfile *epfile = inode->i_private;
1347         struct ffs_dmabuf_priv *priv, *tmp;
1348         struct ffs_data *ffs = epfile->ffs;
1349
1350         mutex_lock(&epfile->dmabufs_mutex);
1351
1352         /* Close all attached DMABUFs */
1353         list_for_each_entry_safe(priv, tmp, &epfile->dmabufs, entry) {
1354                 /* Cancel any pending transfer */
1355                 spin_lock_irq(&ffs->eps_lock);
1356                 if (priv->ep && priv->req)
1357                         usb_ep_dequeue(priv->ep, priv->req);
1358                 spin_unlock_irq(&ffs->eps_lock);
1359
1360                 list_del(&priv->entry);
1361                 ffs_dmabuf_put(priv->attach);
1362         }
1363
1364         mutex_unlock(&epfile->dmabufs_mutex);
1365
1366         __ffs_epfile_read_buffer_free(epfile);
1367         ffs_data_closed(epfile->ffs);
1368
1369         return 0;
1370 }
1371
1372 static void ffs_dmabuf_cleanup(struct work_struct *work)
1373 {
1374         struct ffs_dma_fence *dma_fence =
1375                 container_of(work, struct ffs_dma_fence, work);
1376         struct ffs_dmabuf_priv *priv = dma_fence->priv;
1377         struct dma_buf_attachment *attach = priv->attach;
1378         struct dma_fence *fence = &dma_fence->base;
1379
1380         ffs_dmabuf_put(attach);
1381         dma_fence_put(fence);
1382 }
1383
1384 static void ffs_dmabuf_signal_done(struct ffs_dma_fence *dma_fence, int ret)
1385 {
1386         struct ffs_dmabuf_priv *priv = dma_fence->priv;
1387         struct dma_fence *fence = &dma_fence->base;
1388         bool cookie = dma_fence_begin_signalling();
1389
1390         dma_fence_get(fence);
1391         fence->error = ret;
1392         dma_fence_signal(fence);
1393         dma_fence_end_signalling(cookie);
1394
1395         /*
1396          * The fence will be unref'd in ffs_dmabuf_cleanup.
1397          * It can't be done here, as the unref functions might try to lock
1398          * the resv object, which would deadlock.
1399          */
1400         INIT_WORK(&dma_fence->work, ffs_dmabuf_cleanup);
1401         queue_work(priv->ffs->io_completion_wq, &dma_fence->work);
1402 }
1403
1404 static void ffs_epfile_dmabuf_io_complete(struct usb_ep *ep,
1405                                           struct usb_request *req)
1406 {
1407         pr_vdebug("FFS: DMABUF transfer complete, status=%d\n", req->status);
1408         ffs_dmabuf_signal_done(req->context, req->status);
1409         usb_ep_free_request(ep, req);
1410 }
1411
1412 static const char *ffs_dmabuf_get_driver_name(struct dma_fence *fence)
1413 {
1414         return "functionfs";
1415 }
1416
1417 static const char *ffs_dmabuf_get_timeline_name(struct dma_fence *fence)
1418 {
1419         return "";
1420 }
1421
1422 static void ffs_dmabuf_fence_release(struct dma_fence *fence)
1423 {
1424         struct ffs_dma_fence *dma_fence =
1425                 container_of(fence, struct ffs_dma_fence, base);
1426
1427         kfree(dma_fence);
1428 }
1429
1430 static const struct dma_fence_ops ffs_dmabuf_fence_ops = {
1431         .get_driver_name        = ffs_dmabuf_get_driver_name,
1432         .get_timeline_name      = ffs_dmabuf_get_timeline_name,
1433         .release                = ffs_dmabuf_fence_release,
1434 };
1435
1436 static int ffs_dma_resv_lock(struct dma_buf *dmabuf, bool nonblock)
1437 {
1438         if (!nonblock)
1439                 return dma_resv_lock_interruptible(dmabuf->resv, NULL);
1440
1441         if (!dma_resv_trylock(dmabuf->resv))
1442                 return -EBUSY;
1443
1444         return 0;
1445 }
1446
1447 static struct dma_buf_attachment *
1448 ffs_dmabuf_find_attachment(struct ffs_epfile *epfile, struct dma_buf *dmabuf)
1449 {
1450         struct device *dev = epfile->ffs->gadget->dev.parent;
1451         struct dma_buf_attachment *attach = NULL;
1452         struct ffs_dmabuf_priv *priv;
1453
1454         mutex_lock(&epfile->dmabufs_mutex);
1455
1456         list_for_each_entry(priv, &epfile->dmabufs, entry) {
1457                 if (priv->attach->dev == dev
1458                     && priv->attach->dmabuf == dmabuf) {
1459                         attach = priv->attach;
1460                         break;
1461                 }
1462         }
1463
1464         if (attach)
1465                 ffs_dmabuf_get(attach);
1466
1467         mutex_unlock(&epfile->dmabufs_mutex);
1468
1469         return attach ?: ERR_PTR(-EPERM);
1470 }
1471
1472 static int ffs_dmabuf_attach(struct file *file, int fd)
1473 {
1474         bool nonblock = file->f_flags & O_NONBLOCK;
1475         struct ffs_epfile *epfile = file->private_data;
1476         struct usb_gadget *gadget = epfile->ffs->gadget;
1477         struct dma_buf_attachment *attach;
1478         struct ffs_dmabuf_priv *priv;
1479         enum dma_data_direction dir;
1480         struct sg_table *sg_table;
1481         struct dma_buf *dmabuf;
1482         int err;
1483
1484         if (!gadget || !gadget->sg_supported)
1485                 return -EPERM;
1486
1487         dmabuf = dma_buf_get(fd);
1488         if (IS_ERR(dmabuf))
1489                 return PTR_ERR(dmabuf);
1490
1491         attach = dma_buf_attach(dmabuf, gadget->dev.parent);
1492         if (IS_ERR(attach)) {
1493                 err = PTR_ERR(attach);
1494                 goto err_dmabuf_put;
1495         }
1496
1497         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1498         if (!priv) {
1499                 err = -ENOMEM;
1500                 goto err_dmabuf_detach;
1501         }
1502
1503         dir = epfile->in ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
1504
1505         err = ffs_dma_resv_lock(dmabuf, nonblock);
1506         if (err)
1507                 goto err_free_priv;
1508
1509         sg_table = dma_buf_map_attachment(attach, dir);
1510         dma_resv_unlock(dmabuf->resv);
1511
1512         if (IS_ERR(sg_table)) {
1513                 err = PTR_ERR(sg_table);
1514                 goto err_free_priv;
1515         }
1516
1517         attach->importer_priv = priv;
1518
1519         priv->sgt = sg_table;
1520         priv->dir = dir;
1521         priv->ffs = epfile->ffs;
1522         priv->attach = attach;
1523         spin_lock_init(&priv->lock);
1524         kref_init(&priv->ref);
1525         priv->context = dma_fence_context_alloc(1);
1526
1527         mutex_lock(&epfile->dmabufs_mutex);
1528         list_add(&priv->entry, &epfile->dmabufs);
1529         mutex_unlock(&epfile->dmabufs_mutex);
1530
1531         return 0;
1532
1533 err_free_priv:
1534         kfree(priv);
1535 err_dmabuf_detach:
1536         dma_buf_detach(dmabuf, attach);
1537 err_dmabuf_put:
1538         dma_buf_put(dmabuf);
1539
1540         return err;
1541 }
1542
1543 static int ffs_dmabuf_detach(struct file *file, int fd)
1544 {
1545         struct ffs_epfile *epfile = file->private_data;
1546         struct ffs_data *ffs = epfile->ffs;
1547         struct device *dev = ffs->gadget->dev.parent;
1548         struct ffs_dmabuf_priv *priv, *tmp;
1549         struct dma_buf *dmabuf;
1550         int ret = -EPERM;
1551
1552         dmabuf = dma_buf_get(fd);
1553         if (IS_ERR(dmabuf))
1554                 return PTR_ERR(dmabuf);
1555
1556         mutex_lock(&epfile->dmabufs_mutex);
1557
1558         list_for_each_entry_safe(priv, tmp, &epfile->dmabufs, entry) {
1559                 if (priv->attach->dev == dev
1560                     && priv->attach->dmabuf == dmabuf) {
1561                         /* Cancel any pending transfer */
1562                         spin_lock_irq(&ffs->eps_lock);
1563                         if (priv->ep && priv->req)
1564                                 usb_ep_dequeue(priv->ep, priv->req);
1565                         spin_unlock_irq(&ffs->eps_lock);
1566
1567                         list_del(&priv->entry);
1568
1569                         /* Unref the reference from ffs_dmabuf_attach() */
1570                         ffs_dmabuf_put(priv->attach);
1571                         ret = 0;
1572                         break;
1573                 }
1574         }
1575
1576         mutex_unlock(&epfile->dmabufs_mutex);
1577         dma_buf_put(dmabuf);
1578
1579         return ret;
1580 }
1581
1582 static int ffs_dmabuf_transfer(struct file *file,
1583                                const struct usb_ffs_dmabuf_transfer_req *req)
1584 {
1585         bool nonblock = file->f_flags & O_NONBLOCK;
1586         struct ffs_epfile *epfile = file->private_data;
1587         struct dma_buf_attachment *attach;
1588         struct ffs_dmabuf_priv *priv;
1589         struct ffs_dma_fence *fence;
1590         struct usb_request *usb_req;
1591         enum dma_resv_usage resv_dir;
1592         struct dma_buf *dmabuf;
1593         unsigned long timeout;
1594         struct ffs_ep *ep;
1595         bool cookie;
1596         u32 seqno;
1597         long retl;
1598         int ret;
1599
1600         if (req->flags & ~USB_FFS_DMABUF_TRANSFER_MASK)
1601                 return -EINVAL;
1602
1603         dmabuf = dma_buf_get(req->fd);
1604         if (IS_ERR(dmabuf))
1605                 return PTR_ERR(dmabuf);
1606
1607         if (req->length > dmabuf->size || req->length == 0) {
1608                 ret = -EINVAL;
1609                 goto err_dmabuf_put;
1610         }
1611
1612         attach = ffs_dmabuf_find_attachment(epfile, dmabuf);
1613         if (IS_ERR(attach)) {
1614                 ret = PTR_ERR(attach);
1615                 goto err_dmabuf_put;
1616         }
1617
1618         priv = attach->importer_priv;
1619
1620         ep = ffs_epfile_wait_ep(file);
1621         if (IS_ERR(ep)) {
1622                 ret = PTR_ERR(ep);
1623                 goto err_attachment_put;
1624         }
1625
1626         ret = ffs_dma_resv_lock(dmabuf, nonblock);
1627         if (ret)
1628                 goto err_attachment_put;
1629
1630         /* Make sure we don't have writers */
1631         timeout = nonblock ? 0 : msecs_to_jiffies(DMABUF_ENQUEUE_TIMEOUT_MS);
1632         retl = dma_resv_wait_timeout(dmabuf->resv,
1633                                      dma_resv_usage_rw(epfile->in),
1634                                      true, timeout);
1635         if (retl == 0)
1636                 retl = -EBUSY;
1637         if (retl < 0) {
1638                 ret = (int)retl;
1639                 goto err_resv_unlock;
1640         }
1641
1642         ret = dma_resv_reserve_fences(dmabuf->resv, 1);
1643         if (ret)
1644                 goto err_resv_unlock;
1645
1646         fence = kmalloc(sizeof(*fence), GFP_KERNEL);
1647         if (!fence) {
1648                 ret = -ENOMEM;
1649                 goto err_resv_unlock;
1650         }
1651
1652         fence->priv = priv;
1653
1654         spin_lock_irq(&epfile->ffs->eps_lock);
1655
1656         /* In the meantime, endpoint got disabled or changed. */
1657         if (epfile->ep != ep) {
1658                 ret = -ESHUTDOWN;
1659                 goto err_fence_put;
1660         }
1661
1662         usb_req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC);
1663         if (!usb_req) {
1664                 ret = -ENOMEM;
1665                 goto err_fence_put;
1666         }
1667
1668         /*
1669          * usb_ep_queue() guarantees that all transfers are processed in the
1670          * order they are enqueued, so we can use a simple incrementing
1671          * sequence number for the dma_fence.
1672          */
1673         seqno = atomic_add_return(1, &epfile->seqno);
1674
1675         dma_fence_init(&fence->base, &ffs_dmabuf_fence_ops,
1676                        &priv->lock, priv->context, seqno);
1677
1678         resv_dir = epfile->in ? DMA_RESV_USAGE_WRITE : DMA_RESV_USAGE_READ;
1679
1680         dma_resv_add_fence(dmabuf->resv, &fence->base, resv_dir);
1681         dma_resv_unlock(dmabuf->resv);
1682
1683         /* Now that the dma_fence is in place, queue the transfer. */
1684
1685         usb_req->length = req->length;
1686         usb_req->buf = NULL;
1687         usb_req->sg = priv->sgt->sgl;
1688         usb_req->num_sgs = sg_nents_for_len(priv->sgt->sgl, req->length);
1689         usb_req->sg_was_mapped = true;
1690         usb_req->context  = fence;
1691         usb_req->complete = ffs_epfile_dmabuf_io_complete;
1692
1693         cookie = dma_fence_begin_signalling();
1694         ret = usb_ep_queue(ep->ep, usb_req, GFP_ATOMIC);
1695         dma_fence_end_signalling(cookie);
1696         if (!ret) {
1697                 priv->req = usb_req;
1698                 priv->ep = ep->ep;
1699         } else {
1700                 pr_warn("FFS: Failed to queue DMABUF: %d\n", ret);
1701                 ffs_dmabuf_signal_done(fence, ret);
1702                 usb_ep_free_request(ep->ep, usb_req);
1703         }
1704
1705         spin_unlock_irq(&epfile->ffs->eps_lock);
1706         dma_buf_put(dmabuf);
1707
1708         return ret;
1709
1710 err_fence_put:
1711         spin_unlock_irq(&epfile->ffs->eps_lock);
1712         dma_fence_put(&fence->base);
1713 err_resv_unlock:
1714         dma_resv_unlock(dmabuf->resv);
1715 err_attachment_put:
1716         ffs_dmabuf_put(attach);
1717 err_dmabuf_put:
1718         dma_buf_put(dmabuf);
1719
1720         return ret;
1721 }
1722
1723 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1724                              unsigned long value)
1725 {
1726         struct ffs_epfile *epfile = file->private_data;
1727         struct ffs_ep *ep;
1728         int ret;
1729
1730         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1731                 return -ENODEV;
1732
1733         switch (code) {
1734         case FUNCTIONFS_DMABUF_ATTACH:
1735         {
1736                 int fd;
1737
1738                 if (copy_from_user(&fd, (void __user *)value, sizeof(fd))) {
1739                         ret = -EFAULT;
1740                         break;
1741                 }
1742
1743                 return ffs_dmabuf_attach(file, fd);
1744         }
1745         case FUNCTIONFS_DMABUF_DETACH:
1746         {
1747                 int fd;
1748
1749                 if (copy_from_user(&fd, (void __user *)value, sizeof(fd))) {
1750                         ret = -EFAULT;
1751                         break;
1752                 }
1753
1754                 return ffs_dmabuf_detach(file, fd);
1755         }
1756         case FUNCTIONFS_DMABUF_TRANSFER:
1757         {
1758                 struct usb_ffs_dmabuf_transfer_req req;
1759
1760                 if (copy_from_user(&req, (void __user *)value, sizeof(req))) {
1761                         ret = -EFAULT;
1762                         break;
1763                 }
1764
1765                 return ffs_dmabuf_transfer(file, &req);
1766         }
1767         default:
1768                 break;
1769         }
1770
1771         /* Wait for endpoint to be enabled */
1772         ep = ffs_epfile_wait_ep(file);
1773         if (IS_ERR(ep))
1774                 return PTR_ERR(ep);
1775
1776         spin_lock_irq(&epfile->ffs->eps_lock);
1777
1778         /* In the meantime, endpoint got disabled or changed. */
1779         if (epfile->ep != ep) {
1780                 spin_unlock_irq(&epfile->ffs->eps_lock);
1781                 return -ESHUTDOWN;
1782         }
1783
1784         switch (code) {
1785         case FUNCTIONFS_FIFO_STATUS:
1786                 ret = usb_ep_fifo_status(epfile->ep->ep);
1787                 break;
1788         case FUNCTIONFS_FIFO_FLUSH:
1789                 usb_ep_fifo_flush(epfile->ep->ep);
1790                 ret = 0;
1791                 break;
1792         case FUNCTIONFS_CLEAR_HALT:
1793                 ret = usb_ep_clear_halt(epfile->ep->ep);
1794                 break;
1795         case FUNCTIONFS_ENDPOINT_REVMAP:
1796                 ret = epfile->ep->num;
1797                 break;
1798         case FUNCTIONFS_ENDPOINT_DESC:
1799         {
1800                 int desc_idx;
1801                 struct usb_endpoint_descriptor desc1, *desc;
1802
1803                 switch (epfile->ffs->gadget->speed) {
1804                 case USB_SPEED_SUPER:
1805                 case USB_SPEED_SUPER_PLUS:
1806                         desc_idx = 2;
1807                         break;
1808                 case USB_SPEED_HIGH:
1809                         desc_idx = 1;
1810                         break;
1811                 default:
1812                         desc_idx = 0;
1813                 }
1814
1815                 desc = epfile->ep->descs[desc_idx];
1816                 memcpy(&desc1, desc, desc->bLength);
1817
1818                 spin_unlock_irq(&epfile->ffs->eps_lock);
1819                 ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
1820                 if (ret)
1821                         ret = -EFAULT;
1822                 return ret;
1823         }
1824         default:
1825                 ret = -ENOTTY;
1826         }
1827         spin_unlock_irq(&epfile->ffs->eps_lock);
1828
1829         return ret;
1830 }
1831
1832 static const struct file_operations ffs_epfile_operations = {
1833         .llseek =       no_llseek,
1834
1835         .open =         ffs_epfile_open,
1836         .write_iter =   ffs_epfile_write_iter,
1837         .read_iter =    ffs_epfile_read_iter,
1838         .release =      ffs_epfile_release,
1839         .unlocked_ioctl =       ffs_epfile_ioctl,
1840         .compat_ioctl = compat_ptr_ioctl,
1841 };
1842
1843
1844 /* File system and super block operations ***********************************/
1845
1846 /*
1847  * Mounting the file system creates a controller file, used first for
1848  * function configuration then later for event monitoring.
1849  */
1850
1851 static struct inode *__must_check
1852 ffs_sb_make_inode(struct super_block *sb, void *data,
1853                   const struct file_operations *fops,
1854                   const struct inode_operations *iops,
1855                   struct ffs_file_perms *perms)
1856 {
1857         struct inode *inode;
1858
1859         inode = new_inode(sb);
1860
1861         if (inode) {
1862                 struct timespec64 ts = inode_set_ctime_current(inode);
1863
1864                 inode->i_ino     = get_next_ino();
1865                 inode->i_mode    = perms->mode;
1866                 inode->i_uid     = perms->uid;
1867                 inode->i_gid     = perms->gid;
1868                 inode_set_atime_to_ts(inode, ts);
1869                 inode_set_mtime_to_ts(inode, ts);
1870                 inode->i_private = data;
1871                 if (fops)
1872                         inode->i_fop = fops;
1873                 if (iops)
1874                         inode->i_op  = iops;
1875         }
1876
1877         return inode;
1878 }
1879
1880 /* Create "regular" file */
1881 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1882                                         const char *name, void *data,
1883                                         const struct file_operations *fops)
1884 {
1885         struct ffs_data *ffs = sb->s_fs_info;
1886         struct dentry   *dentry;
1887         struct inode    *inode;
1888
1889         dentry = d_alloc_name(sb->s_root, name);
1890         if (!dentry)
1891                 return NULL;
1892
1893         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1894         if (!inode) {
1895                 dput(dentry);
1896                 return NULL;
1897         }
1898
1899         d_add(dentry, inode);
1900         return dentry;
1901 }
1902
1903 /* Super block */
1904 static const struct super_operations ffs_sb_operations = {
1905         .statfs =       simple_statfs,
1906         .drop_inode =   generic_delete_inode,
1907 };
1908
1909 struct ffs_sb_fill_data {
1910         struct ffs_file_perms perms;
1911         umode_t root_mode;
1912         const char *dev_name;
1913         bool no_disconnect;
1914         struct ffs_data *ffs_data;
1915 };
1916
1917 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1918 {
1919         struct ffs_sb_fill_data *data = fc->fs_private;
1920         struct inode    *inode;
1921         struct ffs_data *ffs = data->ffs_data;
1922
1923         ffs->sb              = sb;
1924         data->ffs_data       = NULL;
1925         sb->s_fs_info        = ffs;
1926         sb->s_blocksize      = PAGE_SIZE;
1927         sb->s_blocksize_bits = PAGE_SHIFT;
1928         sb->s_magic          = FUNCTIONFS_MAGIC;
1929         sb->s_op             = &ffs_sb_operations;
1930         sb->s_time_gran      = 1;
1931
1932         /* Root inode */
1933         data->perms.mode = data->root_mode;
1934         inode = ffs_sb_make_inode(sb, NULL,
1935                                   &simple_dir_operations,
1936                                   &simple_dir_inode_operations,
1937                                   &data->perms);
1938         sb->s_root = d_make_root(inode);
1939         if (!sb->s_root)
1940                 return -ENOMEM;
1941
1942         /* EP0 file */
1943         if (!ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations))
1944                 return -ENOMEM;
1945
1946         return 0;
1947 }
1948
1949 enum {
1950         Opt_no_disconnect,
1951         Opt_rmode,
1952         Opt_fmode,
1953         Opt_mode,
1954         Opt_uid,
1955         Opt_gid,
1956 };
1957
1958 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1959         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1960         fsparam_u32     ("rmode",               Opt_rmode),
1961         fsparam_u32     ("fmode",               Opt_fmode),
1962         fsparam_u32     ("mode",                Opt_mode),
1963         fsparam_u32     ("uid",                 Opt_uid),
1964         fsparam_u32     ("gid",                 Opt_gid),
1965         {}
1966 };
1967
1968 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1969 {
1970         struct ffs_sb_fill_data *data = fc->fs_private;
1971         struct fs_parse_result result;
1972         int opt;
1973
1974         opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1975         if (opt < 0)
1976                 return opt;
1977
1978         switch (opt) {
1979         case Opt_no_disconnect:
1980                 data->no_disconnect = result.boolean;
1981                 break;
1982         case Opt_rmode:
1983                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1984                 break;
1985         case Opt_fmode:
1986                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1987                 break;
1988         case Opt_mode:
1989                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1990                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1991                 break;
1992
1993         case Opt_uid:
1994                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1995                 if (!uid_valid(data->perms.uid))
1996                         goto unmapped_value;
1997                 break;
1998         case Opt_gid:
1999                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
2000                 if (!gid_valid(data->perms.gid))
2001                         goto unmapped_value;
2002                 break;
2003
2004         default:
2005                 return -ENOPARAM;
2006         }
2007
2008         return 0;
2009
2010 unmapped_value:
2011         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
2012 }
2013
2014 /*
2015  * Set up the superblock for a mount.
2016  */
2017 static int ffs_fs_get_tree(struct fs_context *fc)
2018 {
2019         struct ffs_sb_fill_data *ctx = fc->fs_private;
2020         struct ffs_data *ffs;
2021         int ret;
2022
2023         if (!fc->source)
2024                 return invalf(fc, "No source specified");
2025
2026         ffs = ffs_data_new(fc->source);
2027         if (!ffs)
2028                 return -ENOMEM;
2029         ffs->file_perms = ctx->perms;
2030         ffs->no_disconnect = ctx->no_disconnect;
2031
2032         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
2033         if (!ffs->dev_name) {
2034                 ffs_data_put(ffs);
2035                 return -ENOMEM;
2036         }
2037
2038         ret = ffs_acquire_dev(ffs->dev_name, ffs);
2039         if (ret) {
2040                 ffs_data_put(ffs);
2041                 return ret;
2042         }
2043
2044         ctx->ffs_data = ffs;
2045         return get_tree_nodev(fc, ffs_sb_fill);
2046 }
2047
2048 static void ffs_fs_free_fc(struct fs_context *fc)
2049 {
2050         struct ffs_sb_fill_data *ctx = fc->fs_private;
2051
2052         if (ctx) {
2053                 if (ctx->ffs_data) {
2054                         ffs_data_put(ctx->ffs_data);
2055                 }
2056
2057                 kfree(ctx);
2058         }
2059 }
2060
2061 static const struct fs_context_operations ffs_fs_context_ops = {
2062         .free           = ffs_fs_free_fc,
2063         .parse_param    = ffs_fs_parse_param,
2064         .get_tree       = ffs_fs_get_tree,
2065 };
2066
2067 static int ffs_fs_init_fs_context(struct fs_context *fc)
2068 {
2069         struct ffs_sb_fill_data *ctx;
2070
2071         ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
2072         if (!ctx)
2073                 return -ENOMEM;
2074
2075         ctx->perms.mode = S_IFREG | 0600;
2076         ctx->perms.uid = GLOBAL_ROOT_UID;
2077         ctx->perms.gid = GLOBAL_ROOT_GID;
2078         ctx->root_mode = S_IFDIR | 0500;
2079         ctx->no_disconnect = false;
2080
2081         fc->fs_private = ctx;
2082         fc->ops = &ffs_fs_context_ops;
2083         return 0;
2084 }
2085
2086 static void
2087 ffs_fs_kill_sb(struct super_block *sb)
2088 {
2089         kill_litter_super(sb);
2090         if (sb->s_fs_info)
2091                 ffs_data_closed(sb->s_fs_info);
2092 }
2093
2094 static struct file_system_type ffs_fs_type = {
2095         .owner          = THIS_MODULE,
2096         .name           = "functionfs",
2097         .init_fs_context = ffs_fs_init_fs_context,
2098         .parameters     = ffs_fs_fs_parameters,
2099         .kill_sb        = ffs_fs_kill_sb,
2100 };
2101 MODULE_ALIAS_FS("functionfs");
2102
2103
2104 /* Driver's main init/cleanup functions *************************************/
2105
2106 static int functionfs_init(void)
2107 {
2108         int ret;
2109
2110         ret = register_filesystem(&ffs_fs_type);
2111         if (!ret)
2112                 pr_info("file system registered\n");
2113         else
2114                 pr_err("failed registering file system (%d)\n", ret);
2115
2116         return ret;
2117 }
2118
2119 static void functionfs_cleanup(void)
2120 {
2121         pr_info("unloading\n");
2122         unregister_filesystem(&ffs_fs_type);
2123 }
2124
2125
2126 /* ffs_data and ffs_function construction and destruction code **************/
2127
2128 static void ffs_data_clear(struct ffs_data *ffs);
2129 static void ffs_data_reset(struct ffs_data *ffs);
2130
2131 static void ffs_data_get(struct ffs_data *ffs)
2132 {
2133         refcount_inc(&ffs->ref);
2134 }
2135
2136 static void ffs_data_opened(struct ffs_data *ffs)
2137 {
2138         refcount_inc(&ffs->ref);
2139         if (atomic_add_return(1, &ffs->opened) == 1 &&
2140                         ffs->state == FFS_DEACTIVATED) {
2141                 ffs->state = FFS_CLOSING;
2142                 ffs_data_reset(ffs);
2143         }
2144 }
2145
2146 static void ffs_data_put(struct ffs_data *ffs)
2147 {
2148         if (refcount_dec_and_test(&ffs->ref)) {
2149                 pr_info("%s(): freeing\n", __func__);
2150                 ffs_data_clear(ffs);
2151                 ffs_release_dev(ffs->private_data);
2152                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
2153                        swait_active(&ffs->ep0req_completion.wait) ||
2154                        waitqueue_active(&ffs->wait));
2155                 destroy_workqueue(ffs->io_completion_wq);
2156                 kfree(ffs->dev_name);
2157                 kfree(ffs);
2158         }
2159 }
2160
2161 static void ffs_data_closed(struct ffs_data *ffs)
2162 {
2163         struct ffs_epfile *epfiles;
2164         unsigned long flags;
2165
2166         if (atomic_dec_and_test(&ffs->opened)) {
2167                 if (ffs->no_disconnect) {
2168                         ffs->state = FFS_DEACTIVATED;
2169                         spin_lock_irqsave(&ffs->eps_lock, flags);
2170                         epfiles = ffs->epfiles;
2171                         ffs->epfiles = NULL;
2172                         spin_unlock_irqrestore(&ffs->eps_lock,
2173                                                         flags);
2174
2175                         if (epfiles)
2176                                 ffs_epfiles_destroy(epfiles,
2177                                                  ffs->eps_count);
2178
2179                         if (ffs->setup_state == FFS_SETUP_PENDING)
2180                                 __ffs_ep0_stall(ffs);
2181                 } else {
2182                         ffs->state = FFS_CLOSING;
2183                         ffs_data_reset(ffs);
2184                 }
2185         }
2186         if (atomic_read(&ffs->opened) < 0) {
2187                 ffs->state = FFS_CLOSING;
2188                 ffs_data_reset(ffs);
2189         }
2190
2191         ffs_data_put(ffs);
2192 }
2193
2194 static struct ffs_data *ffs_data_new(const char *dev_name)
2195 {
2196         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
2197         if (!ffs)
2198                 return NULL;
2199
2200         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
2201         if (!ffs->io_completion_wq) {
2202                 kfree(ffs);
2203                 return NULL;
2204         }
2205
2206         refcount_set(&ffs->ref, 1);
2207         atomic_set(&ffs->opened, 0);
2208         ffs->state = FFS_READ_DESCRIPTORS;
2209         mutex_init(&ffs->mutex);
2210         spin_lock_init(&ffs->eps_lock);
2211         init_waitqueue_head(&ffs->ev.waitq);
2212         init_waitqueue_head(&ffs->wait);
2213         init_completion(&ffs->ep0req_completion);
2214
2215         /* XXX REVISIT need to update it in some places, or do we? */
2216         ffs->ev.can_stall = 1;
2217
2218         return ffs;
2219 }
2220
2221 static void ffs_data_clear(struct ffs_data *ffs)
2222 {
2223         struct ffs_epfile *epfiles;
2224         unsigned long flags;
2225
2226         ffs_closed(ffs);
2227
2228         BUG_ON(ffs->gadget);
2229
2230         spin_lock_irqsave(&ffs->eps_lock, flags);
2231         epfiles = ffs->epfiles;
2232         ffs->epfiles = NULL;
2233         spin_unlock_irqrestore(&ffs->eps_lock, flags);
2234
2235         /*
2236          * potential race possible between ffs_func_eps_disable
2237          * & ffs_epfile_release therefore maintaining a local
2238          * copy of epfile will save us from use-after-free.
2239          */
2240         if (epfiles) {
2241                 ffs_epfiles_destroy(epfiles, ffs->eps_count);
2242                 ffs->epfiles = NULL;
2243         }
2244
2245         if (ffs->ffs_eventfd) {
2246                 eventfd_ctx_put(ffs->ffs_eventfd);
2247                 ffs->ffs_eventfd = NULL;
2248         }
2249
2250         kfree(ffs->raw_descs_data);
2251         kfree(ffs->raw_strings);
2252         kfree(ffs->stringtabs);
2253 }
2254
2255 static void ffs_data_reset(struct ffs_data *ffs)
2256 {
2257         ffs_data_clear(ffs);
2258
2259         ffs->raw_descs_data = NULL;
2260         ffs->raw_descs = NULL;
2261         ffs->raw_strings = NULL;
2262         ffs->stringtabs = NULL;
2263
2264         ffs->raw_descs_length = 0;
2265         ffs->fs_descs_count = 0;
2266         ffs->hs_descs_count = 0;
2267         ffs->ss_descs_count = 0;
2268
2269         ffs->strings_count = 0;
2270         ffs->interfaces_count = 0;
2271         ffs->eps_count = 0;
2272
2273         ffs->ev.count = 0;
2274
2275         ffs->state = FFS_READ_DESCRIPTORS;
2276         ffs->setup_state = FFS_NO_SETUP;
2277         ffs->flags = 0;
2278
2279         ffs->ms_os_descs_ext_prop_count = 0;
2280         ffs->ms_os_descs_ext_prop_name_len = 0;
2281         ffs->ms_os_descs_ext_prop_data_len = 0;
2282 }
2283
2284
2285 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
2286 {
2287         struct usb_gadget_strings **lang;
2288         int first_id;
2289
2290         if (WARN_ON(ffs->state != FFS_ACTIVE
2291                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
2292                 return -EBADFD;
2293
2294         first_id = usb_string_ids_n(cdev, ffs->strings_count);
2295         if (first_id < 0)
2296                 return first_id;
2297
2298         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
2299         if (!ffs->ep0req)
2300                 return -ENOMEM;
2301         ffs->ep0req->complete = ffs_ep0_complete;
2302         ffs->ep0req->context = ffs;
2303
2304         lang = ffs->stringtabs;
2305         if (lang) {
2306                 for (; *lang; ++lang) {
2307                         struct usb_string *str = (*lang)->strings;
2308                         int id = first_id;
2309                         for (; str->s; ++id, ++str)
2310                                 str->id = id;
2311                 }
2312         }
2313
2314         ffs->gadget = cdev->gadget;
2315         ffs_data_get(ffs);
2316         return 0;
2317 }
2318
2319 static void functionfs_unbind(struct ffs_data *ffs)
2320 {
2321         if (!WARN_ON(!ffs->gadget)) {
2322                 /* dequeue before freeing ep0req */
2323                 usb_ep_dequeue(ffs->gadget->ep0, ffs->ep0req);
2324                 mutex_lock(&ffs->mutex);
2325                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
2326                 ffs->ep0req = NULL;
2327                 ffs->gadget = NULL;
2328                 clear_bit(FFS_FL_BOUND, &ffs->flags);
2329                 mutex_unlock(&ffs->mutex);
2330                 ffs_data_put(ffs);
2331         }
2332 }
2333
2334 static int ffs_epfiles_create(struct ffs_data *ffs)
2335 {
2336         struct ffs_epfile *epfile, *epfiles;
2337         unsigned i, count;
2338
2339         count = ffs->eps_count;
2340         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
2341         if (!epfiles)
2342                 return -ENOMEM;
2343
2344         epfile = epfiles;
2345         for (i = 1; i <= count; ++i, ++epfile) {
2346                 epfile->ffs = ffs;
2347                 mutex_init(&epfile->mutex);
2348                 mutex_init(&epfile->dmabufs_mutex);
2349                 INIT_LIST_HEAD(&epfile->dmabufs);
2350                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2351                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
2352                 else
2353                         sprintf(epfile->name, "ep%u", i);
2354                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
2355                                                  epfile,
2356                                                  &ffs_epfile_operations);
2357                 if (!epfile->dentry) {
2358                         ffs_epfiles_destroy(epfiles, i - 1);
2359                         return -ENOMEM;
2360                 }
2361         }
2362
2363         ffs->epfiles = epfiles;
2364         return 0;
2365 }
2366
2367 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
2368 {
2369         struct ffs_epfile *epfile = epfiles;
2370
2371         for (; count; --count, ++epfile) {
2372                 BUG_ON(mutex_is_locked(&epfile->mutex));
2373                 if (epfile->dentry) {
2374                         d_delete(epfile->dentry);
2375                         dput(epfile->dentry);
2376                         epfile->dentry = NULL;
2377                 }
2378         }
2379
2380         kfree(epfiles);
2381 }
2382
2383 static void ffs_func_eps_disable(struct ffs_function *func)
2384 {
2385         struct ffs_ep *ep;
2386         struct ffs_epfile *epfile;
2387         unsigned short count;
2388         unsigned long flags;
2389
2390         spin_lock_irqsave(&func->ffs->eps_lock, flags);
2391         count = func->ffs->eps_count;
2392         epfile = func->ffs->epfiles;
2393         ep = func->eps;
2394         while (count--) {
2395                 /* pending requests get nuked */
2396                 if (ep->ep)
2397                         usb_ep_disable(ep->ep);
2398                 ++ep;
2399
2400                 if (epfile) {
2401                         epfile->ep = NULL;
2402                         __ffs_epfile_read_buffer_free(epfile);
2403                         ++epfile;
2404                 }
2405         }
2406         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2407 }
2408
2409 static int ffs_func_eps_enable(struct ffs_function *func)
2410 {
2411         struct ffs_data *ffs;
2412         struct ffs_ep *ep;
2413         struct ffs_epfile *epfile;
2414         unsigned short count;
2415         unsigned long flags;
2416         int ret = 0;
2417
2418         spin_lock_irqsave(&func->ffs->eps_lock, flags);
2419         ffs = func->ffs;
2420         ep = func->eps;
2421         epfile = ffs->epfiles;
2422         count = ffs->eps_count;
2423         while(count--) {
2424                 ep->ep->driver_data = ep;
2425
2426                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
2427                 if (ret) {
2428                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
2429                                         __func__, ep->ep->name, ret);
2430                         break;
2431                 }
2432
2433                 ret = usb_ep_enable(ep->ep);
2434                 if (!ret) {
2435                         epfile->ep = ep;
2436                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
2437                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
2438                 } else {
2439                         break;
2440                 }
2441
2442                 ++ep;
2443                 ++epfile;
2444         }
2445
2446         wake_up_interruptible(&ffs->wait);
2447         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2448
2449         return ret;
2450 }
2451
2452
2453 /* Parsing and building descriptors and strings *****************************/
2454
2455 /*
2456  * This validates if data pointed by data is a valid USB descriptor as
2457  * well as record how many interfaces, endpoints and strings are
2458  * required by given configuration.  Returns address after the
2459  * descriptor or NULL if data is invalid.
2460  */
2461
2462 enum ffs_entity_type {
2463         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
2464 };
2465
2466 enum ffs_os_desc_type {
2467         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
2468 };
2469
2470 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2471                                    u8 *valuep,
2472                                    struct usb_descriptor_header *desc,
2473                                    void *priv);
2474
2475 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2476                                     struct usb_os_desc_header *h, void *data,
2477                                     unsigned len, void *priv);
2478
2479 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2480                                            ffs_entity_callback entity,
2481                                            void *priv, int *current_class)
2482 {
2483         struct usb_descriptor_header *_ds = (void *)data;
2484         u8 length;
2485         int ret;
2486
2487         /* At least two bytes are required: length and type */
2488         if (len < 2) {
2489                 pr_vdebug("descriptor too short\n");
2490                 return -EINVAL;
2491         }
2492
2493         /* If we have at least as many bytes as the descriptor takes? */
2494         length = _ds->bLength;
2495         if (len < length) {
2496                 pr_vdebug("descriptor longer then available data\n");
2497                 return -EINVAL;
2498         }
2499
2500 #define __entity_check_INTERFACE(val)  1
2501 #define __entity_check_STRING(val)     (val)
2502 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2503 #define __entity(type, val) do {                                        \
2504                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2505                 if (!__entity_check_ ##type(val)) {                     \
2506                         pr_vdebug("invalid entity's value\n");          \
2507                         return -EINVAL;                                 \
2508                 }                                                       \
2509                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2510                 if (ret < 0) {                                          \
2511                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2512                                  (val), ret);                           \
2513                         return ret;                                     \
2514                 }                                                       \
2515         } while (0)
2516
2517         /* Parse descriptor depending on type. */
2518         switch (_ds->bDescriptorType) {
2519         case USB_DT_DEVICE:
2520         case USB_DT_CONFIG:
2521         case USB_DT_STRING:
2522         case USB_DT_DEVICE_QUALIFIER:
2523                 /* function can't have any of those */
2524                 pr_vdebug("descriptor reserved for gadget: %d\n",
2525                       _ds->bDescriptorType);
2526                 return -EINVAL;
2527
2528         case USB_DT_INTERFACE: {
2529                 struct usb_interface_descriptor *ds = (void *)_ds;
2530                 pr_vdebug("interface descriptor\n");
2531                 if (length != sizeof *ds)
2532                         goto inv_length;
2533
2534                 __entity(INTERFACE, ds->bInterfaceNumber);
2535                 if (ds->iInterface)
2536                         __entity(STRING, ds->iInterface);
2537                 *current_class = ds->bInterfaceClass;
2538         }
2539                 break;
2540
2541         case USB_DT_ENDPOINT: {
2542                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2543                 pr_vdebug("endpoint descriptor\n");
2544                 if (length != USB_DT_ENDPOINT_SIZE &&
2545                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2546                         goto inv_length;
2547                 __entity(ENDPOINT, ds->bEndpointAddress);
2548         }
2549                 break;
2550
2551         case USB_TYPE_CLASS | 0x01:
2552                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2553                         pr_vdebug("hid descriptor\n");
2554                         if (length != sizeof(struct hid_descriptor))
2555                                 goto inv_length;
2556                         break;
2557                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2558                         pr_vdebug("ccid descriptor\n");
2559                         if (length != sizeof(struct ccid_descriptor))
2560                                 goto inv_length;
2561                         break;
2562                 } else {
2563                         pr_vdebug("unknown descriptor: %d for class %d\n",
2564                               _ds->bDescriptorType, *current_class);
2565                         return -EINVAL;
2566                 }
2567
2568         case USB_DT_OTG:
2569                 if (length != sizeof(struct usb_otg_descriptor))
2570                         goto inv_length;
2571                 break;
2572
2573         case USB_DT_INTERFACE_ASSOCIATION: {
2574                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2575                 pr_vdebug("interface association descriptor\n");
2576                 if (length != sizeof *ds)
2577                         goto inv_length;
2578                 if (ds->iFunction)
2579                         __entity(STRING, ds->iFunction);
2580         }
2581                 break;
2582
2583         case USB_DT_SS_ENDPOINT_COMP:
2584                 pr_vdebug("EP SS companion descriptor\n");
2585                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2586                         goto inv_length;
2587                 break;
2588
2589         case USB_DT_OTHER_SPEED_CONFIG:
2590         case USB_DT_INTERFACE_POWER:
2591         case USB_DT_DEBUG:
2592         case USB_DT_SECURITY:
2593         case USB_DT_CS_RADIO_CONTROL:
2594                 /* TODO */
2595                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2596                 return -EINVAL;
2597
2598         default:
2599                 /* We should never be here */
2600                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2601                 return -EINVAL;
2602
2603 inv_length:
2604                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2605                           _ds->bLength, _ds->bDescriptorType);
2606                 return -EINVAL;
2607         }
2608
2609 #undef __entity
2610 #undef __entity_check_DESCRIPTOR
2611 #undef __entity_check_INTERFACE
2612 #undef __entity_check_STRING
2613 #undef __entity_check_ENDPOINT
2614
2615         return length;
2616 }
2617
2618 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2619                                      ffs_entity_callback entity, void *priv)
2620 {
2621         const unsigned _len = len;
2622         unsigned long num = 0;
2623         int current_class = -1;
2624
2625         for (;;) {
2626                 int ret;
2627
2628                 if (num == count)
2629                         data = NULL;
2630
2631                 /* Record "descriptor" entity */
2632                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2633                 if (ret < 0) {
2634                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2635                                  num, ret);
2636                         return ret;
2637                 }
2638
2639                 if (!data)
2640                         return _len - len;
2641
2642                 ret = ffs_do_single_desc(data, len, entity, priv,
2643                         &current_class);
2644                 if (ret < 0) {
2645                         pr_debug("%s returns %d\n", __func__, ret);
2646                         return ret;
2647                 }
2648
2649                 len -= ret;
2650                 data += ret;
2651                 ++num;
2652         }
2653 }
2654
2655 static int __ffs_data_do_entity(enum ffs_entity_type type,
2656                                 u8 *valuep, struct usb_descriptor_header *desc,
2657                                 void *priv)
2658 {
2659         struct ffs_desc_helper *helper = priv;
2660         struct usb_endpoint_descriptor *d;
2661
2662         switch (type) {
2663         case FFS_DESCRIPTOR:
2664                 break;
2665
2666         case FFS_INTERFACE:
2667                 /*
2668                  * Interfaces are indexed from zero so if we
2669                  * encountered interface "n" then there are at least
2670                  * "n+1" interfaces.
2671                  */
2672                 if (*valuep >= helper->interfaces_count)
2673                         helper->interfaces_count = *valuep + 1;
2674                 break;
2675
2676         case FFS_STRING:
2677                 /*
2678                  * Strings are indexed from 1 (0 is reserved
2679                  * for languages list)
2680                  */
2681                 if (*valuep > helper->ffs->strings_count)
2682                         helper->ffs->strings_count = *valuep;
2683                 break;
2684
2685         case FFS_ENDPOINT:
2686                 d = (void *)desc;
2687                 helper->eps_count++;
2688                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2689                         return -EINVAL;
2690                 /* Check if descriptors for any speed were already parsed */
2691                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2692                         helper->ffs->eps_addrmap[helper->eps_count] =
2693                                 d->bEndpointAddress;
2694                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2695                                 d->bEndpointAddress)
2696                         return -EINVAL;
2697                 break;
2698         }
2699
2700         return 0;
2701 }
2702
2703 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2704                                    struct usb_os_desc_header *desc)
2705 {
2706         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2707         u16 w_index = le16_to_cpu(desc->wIndex);
2708
2709         if (bcd_version == 0x1) {
2710                 pr_warn("bcdVersion must be 0x0100, stored in Little Endian order. "
2711                         "Userspace driver should be fixed, accepting 0x0001 for compatibility.\n");
2712         } else if (bcd_version != 0x100) {
2713                 pr_vdebug("unsupported os descriptors version: 0x%x\n",
2714                           bcd_version);
2715                 return -EINVAL;
2716         }
2717         switch (w_index) {
2718         case 0x4:
2719                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2720                 break;
2721         case 0x5:
2722                 *next_type = FFS_OS_DESC_EXT_PROP;
2723                 break;
2724         default:
2725                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2726                 return -EINVAL;
2727         }
2728
2729         return sizeof(*desc);
2730 }
2731
2732 /*
2733  * Process all extended compatibility/extended property descriptors
2734  * of a feature descriptor
2735  */
2736 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2737                                               enum ffs_os_desc_type type,
2738                                               u16 feature_count,
2739                                               ffs_os_desc_callback entity,
2740                                               void *priv,
2741                                               struct usb_os_desc_header *h)
2742 {
2743         int ret;
2744         const unsigned _len = len;
2745
2746         /* loop over all ext compat/ext prop descriptors */
2747         while (feature_count--) {
2748                 ret = entity(type, h, data, len, priv);
2749                 if (ret < 0) {
2750                         pr_debug("bad OS descriptor, type: %d\n", type);
2751                         return ret;
2752                 }
2753                 data += ret;
2754                 len -= ret;
2755         }
2756         return _len - len;
2757 }
2758
2759 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2760 static int __must_check ffs_do_os_descs(unsigned count,
2761                                         char *data, unsigned len,
2762                                         ffs_os_desc_callback entity, void *priv)
2763 {
2764         const unsigned _len = len;
2765         unsigned long num = 0;
2766
2767         for (num = 0; num < count; ++num) {
2768                 int ret;
2769                 enum ffs_os_desc_type type;
2770                 u16 feature_count;
2771                 struct usb_os_desc_header *desc = (void *)data;
2772
2773                 if (len < sizeof(*desc))
2774                         return -EINVAL;
2775
2776                 /*
2777                  * Record "descriptor" entity.
2778                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2779                  * Move the data pointer to the beginning of extended
2780                  * compatibilities proper or extended properties proper
2781                  * portions of the data
2782                  */
2783                 if (le32_to_cpu(desc->dwLength) > len)
2784                         return -EINVAL;
2785
2786                 ret = __ffs_do_os_desc_header(&type, desc);
2787                 if (ret < 0) {
2788                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2789                                  num, ret);
2790                         return ret;
2791                 }
2792                 /*
2793                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2794                  */
2795                 feature_count = le16_to_cpu(desc->wCount);
2796                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2797                     (feature_count > 255 || desc->Reserved))
2798                                 return -EINVAL;
2799                 len -= ret;
2800                 data += ret;
2801
2802                 /*
2803                  * Process all function/property descriptors
2804                  * of this Feature Descriptor
2805                  */
2806                 ret = ffs_do_single_os_desc(data, len, type,
2807                                             feature_count, entity, priv, desc);
2808                 if (ret < 0) {
2809                         pr_debug("%s returns %d\n", __func__, ret);
2810                         return ret;
2811                 }
2812
2813                 len -= ret;
2814                 data += ret;
2815         }
2816         return _len - len;
2817 }
2818
2819 /*
2820  * Validate contents of the buffer from userspace related to OS descriptors.
2821  */
2822 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2823                                  struct usb_os_desc_header *h, void *data,
2824                                  unsigned len, void *priv)
2825 {
2826         struct ffs_data *ffs = priv;
2827         u8 length;
2828
2829         switch (type) {
2830         case FFS_OS_DESC_EXT_COMPAT: {
2831                 struct usb_ext_compat_desc *d = data;
2832                 int i;
2833
2834                 if (len < sizeof(*d) ||
2835                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2836                         return -EINVAL;
2837                 if (d->Reserved1 != 1) {
2838                         /*
2839                          * According to the spec, Reserved1 must be set to 1
2840                          * but older kernels incorrectly rejected non-zero
2841                          * values.  We fix it here to avoid returning EINVAL
2842                          * in response to values we used to accept.
2843                          */
2844                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2845                         d->Reserved1 = 1;
2846                 }
2847                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2848                         if (d->Reserved2[i])
2849                                 return -EINVAL;
2850
2851                 length = sizeof(struct usb_ext_compat_desc);
2852         }
2853                 break;
2854         case FFS_OS_DESC_EXT_PROP: {
2855                 struct usb_ext_prop_desc *d = data;
2856                 u32 type, pdl;
2857                 u16 pnl;
2858
2859                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2860                         return -EINVAL;
2861                 length = le32_to_cpu(d->dwSize);
2862                 if (len < length)
2863                         return -EINVAL;
2864                 type = le32_to_cpu(d->dwPropertyDataType);
2865                 if (type < USB_EXT_PROP_UNICODE ||
2866                     type > USB_EXT_PROP_UNICODE_MULTI) {
2867                         pr_vdebug("unsupported os descriptor property type: %d",
2868                                   type);
2869                         return -EINVAL;
2870                 }
2871                 pnl = le16_to_cpu(d->wPropertyNameLength);
2872                 if (length < 14 + pnl) {
2873                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2874                                   length, pnl, type);
2875                         return -EINVAL;
2876                 }
2877                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2878                 if (length != 14 + pnl + pdl) {
2879                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2880                                   length, pnl, pdl, type);
2881                         return -EINVAL;
2882                 }
2883                 ++ffs->ms_os_descs_ext_prop_count;
2884                 /* property name reported to the host as "WCHAR"s */
2885                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2886                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2887         }
2888                 break;
2889         default:
2890                 pr_vdebug("unknown descriptor: %d\n", type);
2891                 return -EINVAL;
2892         }
2893         return length;
2894 }
2895
2896 static int __ffs_data_got_descs(struct ffs_data *ffs,
2897                                 char *const _data, size_t len)
2898 {
2899         char *data = _data, *raw_descs;
2900         unsigned os_descs_count = 0, counts[3], flags;
2901         int ret = -EINVAL, i;
2902         struct ffs_desc_helper helper;
2903
2904         if (get_unaligned_le32(data + 4) != len)
2905                 goto error;
2906
2907         switch (get_unaligned_le32(data)) {
2908         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2909                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2910                 data += 8;
2911                 len  -= 8;
2912                 break;
2913         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2914                 flags = get_unaligned_le32(data + 8);
2915                 ffs->user_flags = flags;
2916                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2917                               FUNCTIONFS_HAS_HS_DESC |
2918                               FUNCTIONFS_HAS_SS_DESC |
2919                               FUNCTIONFS_HAS_MS_OS_DESC |
2920                               FUNCTIONFS_VIRTUAL_ADDR |
2921                               FUNCTIONFS_EVENTFD |
2922                               FUNCTIONFS_ALL_CTRL_RECIP |
2923                               FUNCTIONFS_CONFIG0_SETUP)) {
2924                         ret = -ENOSYS;
2925                         goto error;
2926                 }
2927                 data += 12;
2928                 len  -= 12;
2929                 break;
2930         default:
2931                 goto error;
2932         }
2933
2934         if (flags & FUNCTIONFS_EVENTFD) {
2935                 if (len < 4)
2936                         goto error;
2937                 ffs->ffs_eventfd =
2938                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2939                 if (IS_ERR(ffs->ffs_eventfd)) {
2940                         ret = PTR_ERR(ffs->ffs_eventfd);
2941                         ffs->ffs_eventfd = NULL;
2942                         goto error;
2943                 }
2944                 data += 4;
2945                 len  -= 4;
2946         }
2947
2948         /* Read fs_count, hs_count and ss_count (if present) */
2949         for (i = 0; i < 3; ++i) {
2950                 if (!(flags & (1 << i))) {
2951                         counts[i] = 0;
2952                 } else if (len < 4) {
2953                         goto error;
2954                 } else {
2955                         counts[i] = get_unaligned_le32(data);
2956                         data += 4;
2957                         len  -= 4;
2958                 }
2959         }
2960         if (flags & (1 << i)) {
2961                 if (len < 4) {
2962                         goto error;
2963                 }
2964                 os_descs_count = get_unaligned_le32(data);
2965                 data += 4;
2966                 len -= 4;
2967         }
2968
2969         /* Read descriptors */
2970         raw_descs = data;
2971         helper.ffs = ffs;
2972         for (i = 0; i < 3; ++i) {
2973                 if (!counts[i])
2974                         continue;
2975                 helper.interfaces_count = 0;
2976                 helper.eps_count = 0;
2977                 ret = ffs_do_descs(counts[i], data, len,
2978                                    __ffs_data_do_entity, &helper);
2979                 if (ret < 0)
2980                         goto error;
2981                 if (!ffs->eps_count && !ffs->interfaces_count) {
2982                         ffs->eps_count = helper.eps_count;
2983                         ffs->interfaces_count = helper.interfaces_count;
2984                 } else {
2985                         if (ffs->eps_count != helper.eps_count) {
2986                                 ret = -EINVAL;
2987                                 goto error;
2988                         }
2989                         if (ffs->interfaces_count != helper.interfaces_count) {
2990                                 ret = -EINVAL;
2991                                 goto error;
2992                         }
2993                 }
2994                 data += ret;
2995                 len  -= ret;
2996         }
2997         if (os_descs_count) {
2998                 ret = ffs_do_os_descs(os_descs_count, data, len,
2999                                       __ffs_data_do_os_desc, ffs);
3000                 if (ret < 0)
3001                         goto error;
3002                 data += ret;
3003                 len -= ret;
3004         }
3005
3006         if (raw_descs == data || len) {
3007                 ret = -EINVAL;
3008                 goto error;
3009         }
3010
3011         ffs->raw_descs_data     = _data;
3012         ffs->raw_descs          = raw_descs;
3013         ffs->raw_descs_length   = data - raw_descs;
3014         ffs->fs_descs_count     = counts[0];
3015         ffs->hs_descs_count     = counts[1];
3016         ffs->ss_descs_count     = counts[2];
3017         ffs->ms_os_descs_count  = os_descs_count;
3018
3019         return 0;
3020
3021 error:
3022         kfree(_data);
3023         return ret;
3024 }
3025
3026 static int __ffs_data_got_strings(struct ffs_data *ffs,
3027                                   char *const _data, size_t len)
3028 {
3029         u32 str_count, needed_count, lang_count;
3030         struct usb_gadget_strings **stringtabs, *t;
3031         const char *data = _data;
3032         struct usb_string *s;
3033
3034         if (len < 16 ||
3035             get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
3036             get_unaligned_le32(data + 4) != len)
3037                 goto error;
3038         str_count  = get_unaligned_le32(data + 8);
3039         lang_count = get_unaligned_le32(data + 12);
3040
3041         /* if one is zero the other must be zero */
3042         if (!str_count != !lang_count)
3043                 goto error;
3044
3045         /* Do we have at least as many strings as descriptors need? */
3046         needed_count = ffs->strings_count;
3047         if (str_count < needed_count)
3048                 goto error;
3049
3050         /*
3051          * If we don't need any strings just return and free all
3052          * memory.
3053          */
3054         if (!needed_count) {
3055                 kfree(_data);
3056                 return 0;
3057         }
3058
3059         /* Allocate everything in one chunk so there's less maintenance. */
3060         {
3061                 unsigned i = 0;
3062                 vla_group(d);
3063                 vla_item(d, struct usb_gadget_strings *, stringtabs,
3064                         size_add(lang_count, 1));
3065                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
3066                 vla_item(d, struct usb_string, strings,
3067                         size_mul(lang_count, (needed_count + 1)));
3068
3069                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
3070
3071                 if (!vlabuf) {
3072                         kfree(_data);
3073                         return -ENOMEM;
3074                 }
3075
3076                 /* Initialize the VLA pointers */
3077                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
3078                 t = vla_ptr(vlabuf, d, stringtab);
3079                 i = lang_count;
3080                 do {
3081                         *stringtabs++ = t++;
3082                 } while (--i);
3083                 *stringtabs = NULL;
3084
3085                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
3086                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
3087                 t = vla_ptr(vlabuf, d, stringtab);
3088                 s = vla_ptr(vlabuf, d, strings);
3089         }
3090
3091         /* For each language */
3092         data += 16;
3093         len -= 16;
3094
3095         do { /* lang_count > 0 so we can use do-while */
3096                 unsigned needed = needed_count;
3097                 u32 str_per_lang = str_count;
3098
3099                 if (len < 3)
3100                         goto error_free;
3101                 t->language = get_unaligned_le16(data);
3102                 t->strings  = s;
3103                 ++t;
3104
3105                 data += 2;
3106                 len -= 2;
3107
3108                 /* For each string */
3109                 do { /* str_count > 0 so we can use do-while */
3110                         size_t length = strnlen(data, len);
3111
3112                         if (length == len)
3113                                 goto error_free;
3114
3115                         /*
3116                          * User may provide more strings then we need,
3117                          * if that's the case we simply ignore the
3118                          * rest
3119                          */
3120                         if (needed) {
3121                                 /*
3122                                  * s->id will be set while adding
3123                                  * function to configuration so for
3124                                  * now just leave garbage here.
3125                                  */
3126                                 s->s = data;
3127                                 --needed;
3128                                 ++s;
3129                         }
3130
3131                         data += length + 1;
3132                         len -= length + 1;
3133                 } while (--str_per_lang);
3134
3135                 s->id = 0;   /* terminator */
3136                 s->s = NULL;
3137                 ++s;
3138
3139         } while (--lang_count);
3140
3141         /* Some garbage left? */
3142         if (len)
3143                 goto error_free;
3144
3145         /* Done! */
3146         ffs->stringtabs = stringtabs;
3147         ffs->raw_strings = _data;
3148
3149         return 0;
3150
3151 error_free:
3152         kfree(stringtabs);
3153 error:
3154         kfree(_data);
3155         return -EINVAL;
3156 }
3157
3158
3159 /* Events handling and management *******************************************/
3160
3161 static void __ffs_event_add(struct ffs_data *ffs,
3162                             enum usb_functionfs_event_type type)
3163 {
3164         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
3165         int neg = 0;
3166
3167         /*
3168          * Abort any unhandled setup
3169          *
3170          * We do not need to worry about some cmpxchg() changing value
3171          * of ffs->setup_state without holding the lock because when
3172          * state is FFS_SETUP_PENDING cmpxchg() in several places in
3173          * the source does nothing.
3174          */
3175         if (ffs->setup_state == FFS_SETUP_PENDING)
3176                 ffs->setup_state = FFS_SETUP_CANCELLED;
3177
3178         /*
3179          * Logic of this function guarantees that there are at most four pending
3180          * evens on ffs->ev.types queue.  This is important because the queue
3181          * has space for four elements only and __ffs_ep0_read_events function
3182          * depends on that limit as well.  If more event types are added, those
3183          * limits have to be revisited or guaranteed to still hold.
3184          */
3185         switch (type) {
3186         case FUNCTIONFS_RESUME:
3187                 rem_type2 = FUNCTIONFS_SUSPEND;
3188                 fallthrough;
3189         case FUNCTIONFS_SUSPEND:
3190         case FUNCTIONFS_SETUP:
3191                 rem_type1 = type;
3192                 /* Discard all similar events */
3193                 break;
3194
3195         case FUNCTIONFS_BIND:
3196         case FUNCTIONFS_UNBIND:
3197         case FUNCTIONFS_DISABLE:
3198         case FUNCTIONFS_ENABLE:
3199                 /* Discard everything other then power management. */
3200                 rem_type1 = FUNCTIONFS_SUSPEND;
3201                 rem_type2 = FUNCTIONFS_RESUME;
3202                 neg = 1;
3203                 break;
3204
3205         default:
3206                 WARN(1, "%d: unknown event, this should not happen\n", type);
3207                 return;
3208         }
3209
3210         {
3211                 u8 *ev  = ffs->ev.types, *out = ev;
3212                 unsigned n = ffs->ev.count;
3213                 for (; n; --n, ++ev)
3214                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
3215                                 *out++ = *ev;
3216                         else
3217                                 pr_vdebug("purging event %d\n", *ev);
3218                 ffs->ev.count = out - ffs->ev.types;
3219         }
3220
3221         pr_vdebug("adding event %d\n", type);
3222         ffs->ev.types[ffs->ev.count++] = type;
3223         wake_up_locked(&ffs->ev.waitq);
3224         if (ffs->ffs_eventfd)
3225                 eventfd_signal(ffs->ffs_eventfd);
3226 }
3227
3228 static void ffs_event_add(struct ffs_data *ffs,
3229                           enum usb_functionfs_event_type type)
3230 {
3231         unsigned long flags;
3232         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3233         __ffs_event_add(ffs, type);
3234         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3235 }
3236
3237 /* Bind/unbind USB function hooks *******************************************/
3238
3239 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
3240 {
3241         int i;
3242
3243         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
3244                 if (ffs->eps_addrmap[i] == endpoint_address)
3245                         return i;
3246         return -ENOENT;
3247 }
3248
3249 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
3250                                     struct usb_descriptor_header *desc,
3251                                     void *priv)
3252 {
3253         struct usb_endpoint_descriptor *ds = (void *)desc;
3254         struct ffs_function *func = priv;
3255         struct ffs_ep *ffs_ep;
3256         unsigned ep_desc_id;
3257         int idx;
3258         static const char *speed_names[] = { "full", "high", "super" };
3259
3260         if (type != FFS_DESCRIPTOR)
3261                 return 0;
3262
3263         /*
3264          * If ss_descriptors is not NULL, we are reading super speed
3265          * descriptors; if hs_descriptors is not NULL, we are reading high
3266          * speed descriptors; otherwise, we are reading full speed
3267          * descriptors.
3268          */
3269         if (func->function.ss_descriptors) {
3270                 ep_desc_id = 2;
3271                 func->function.ss_descriptors[(long)valuep] = desc;
3272         } else if (func->function.hs_descriptors) {
3273                 ep_desc_id = 1;
3274                 func->function.hs_descriptors[(long)valuep] = desc;
3275         } else {
3276                 ep_desc_id = 0;
3277                 func->function.fs_descriptors[(long)valuep]    = desc;
3278         }
3279
3280         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
3281                 return 0;
3282
3283         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
3284         if (idx < 0)
3285                 return idx;
3286
3287         ffs_ep = func->eps + idx;
3288
3289         if (ffs_ep->descs[ep_desc_id]) {
3290                 pr_err("two %sspeed descriptors for EP %d\n",
3291                           speed_names[ep_desc_id],
3292                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
3293                 return -EINVAL;
3294         }
3295         ffs_ep->descs[ep_desc_id] = ds;
3296
3297         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
3298         if (ffs_ep->ep) {
3299                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
3300                 if (!ds->wMaxPacketSize)
3301                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
3302         } else {
3303                 struct usb_request *req;
3304                 struct usb_ep *ep;
3305                 u8 bEndpointAddress;
3306                 u16 wMaxPacketSize;
3307
3308                 /*
3309                  * We back up bEndpointAddress because autoconfig overwrites
3310                  * it with physical endpoint address.
3311                  */
3312                 bEndpointAddress = ds->bEndpointAddress;
3313                 /*
3314                  * We back up wMaxPacketSize because autoconfig treats
3315                  * endpoint descriptors as if they were full speed.
3316                  */
3317                 wMaxPacketSize = ds->wMaxPacketSize;
3318                 pr_vdebug("autoconfig\n");
3319                 ep = usb_ep_autoconfig(func->gadget, ds);
3320                 if (!ep)
3321                         return -ENOTSUPP;
3322                 ep->driver_data = func->eps + idx;
3323
3324                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
3325                 if (!req)
3326                         return -ENOMEM;
3327
3328                 ffs_ep->ep  = ep;
3329                 ffs_ep->req = req;
3330                 func->eps_revmap[ds->bEndpointAddress &
3331                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
3332                 /*
3333                  * If we use virtual address mapping, we restore
3334                  * original bEndpointAddress value.
3335                  */
3336                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3337                         ds->bEndpointAddress = bEndpointAddress;
3338                 /*
3339                  * Restore wMaxPacketSize which was potentially
3340                  * overwritten by autoconfig.
3341                  */
3342                 ds->wMaxPacketSize = wMaxPacketSize;
3343         }
3344         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
3345
3346         return 0;
3347 }
3348
3349 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
3350                                    struct usb_descriptor_header *desc,
3351                                    void *priv)
3352 {
3353         struct ffs_function *func = priv;
3354         unsigned idx;
3355         u8 newValue;
3356
3357         switch (type) {
3358         default:
3359         case FFS_DESCRIPTOR:
3360                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
3361                 return 0;
3362
3363         case FFS_INTERFACE:
3364                 idx = *valuep;
3365                 if (func->interfaces_nums[idx] < 0) {
3366                         int id = usb_interface_id(func->conf, &func->function);
3367                         if (id < 0)
3368                                 return id;
3369                         func->interfaces_nums[idx] = id;
3370                 }
3371                 newValue = func->interfaces_nums[idx];
3372                 break;
3373
3374         case FFS_STRING:
3375                 /* String' IDs are allocated when fsf_data is bound to cdev */
3376                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
3377                 break;
3378
3379         case FFS_ENDPOINT:
3380                 /*
3381                  * USB_DT_ENDPOINT are handled in
3382                  * __ffs_func_bind_do_descs().
3383                  */
3384                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
3385                         return 0;
3386
3387                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
3388                 if (!func->eps[idx].ep)
3389                         return -EINVAL;
3390
3391                 {
3392                         struct usb_endpoint_descriptor **descs;
3393                         descs = func->eps[idx].descs;
3394                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
3395                 }
3396                 break;
3397         }
3398
3399         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
3400         *valuep = newValue;
3401         return 0;
3402 }
3403
3404 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
3405                                       struct usb_os_desc_header *h, void *data,
3406                                       unsigned len, void *priv)
3407 {
3408         struct ffs_function *func = priv;
3409         u8 length = 0;
3410
3411         switch (type) {
3412         case FFS_OS_DESC_EXT_COMPAT: {
3413                 struct usb_ext_compat_desc *desc = data;
3414                 struct usb_os_desc_table *t;
3415
3416                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
3417                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
3418                 memcpy(t->os_desc->ext_compat_id, &desc->IDs,
3419                        sizeof_field(struct usb_ext_compat_desc, IDs));
3420                 length = sizeof(*desc);
3421         }
3422                 break;
3423         case FFS_OS_DESC_EXT_PROP: {
3424                 struct usb_ext_prop_desc *desc = data;
3425                 struct usb_os_desc_table *t;
3426                 struct usb_os_desc_ext_prop *ext_prop;
3427                 char *ext_prop_name;
3428                 char *ext_prop_data;
3429
3430                 t = &func->function.os_desc_table[h->interface];
3431                 t->if_id = func->interfaces_nums[h->interface];
3432
3433                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
3434                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
3435
3436                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
3437                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
3438                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
3439                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
3440                 length = ext_prop->name_len + ext_prop->data_len + 14;
3441
3442                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
3443                 func->ffs->ms_os_descs_ext_prop_name_avail +=
3444                         ext_prop->name_len;
3445
3446                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
3447                 func->ffs->ms_os_descs_ext_prop_data_avail +=
3448                         ext_prop->data_len;
3449                 memcpy(ext_prop_data,
3450                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
3451                        ext_prop->data_len);
3452                 /* unicode data reported to the host as "WCHAR"s */
3453                 switch (ext_prop->type) {
3454                 case USB_EXT_PROP_UNICODE:
3455                 case USB_EXT_PROP_UNICODE_ENV:
3456                 case USB_EXT_PROP_UNICODE_LINK:
3457                 case USB_EXT_PROP_UNICODE_MULTI:
3458                         ext_prop->data_len *= 2;
3459                         break;
3460                 }
3461                 ext_prop->data = ext_prop_data;
3462
3463                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3464                        ext_prop->name_len);
3465                 /* property name reported to the host as "WCHAR"s */
3466                 ext_prop->name_len *= 2;
3467                 ext_prop->name = ext_prop_name;
3468
3469                 t->os_desc->ext_prop_len +=
3470                         ext_prop->name_len + ext_prop->data_len + 14;
3471                 ++t->os_desc->ext_prop_count;
3472                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3473         }
3474                 break;
3475         default:
3476                 pr_vdebug("unknown descriptor: %d\n", type);
3477         }
3478
3479         return length;
3480 }
3481
3482 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3483                                                 struct usb_configuration *c)
3484 {
3485         struct ffs_function *func = ffs_func_from_usb(f);
3486         struct f_fs_opts *ffs_opts =
3487                 container_of(f->fi, struct f_fs_opts, func_inst);
3488         struct ffs_data *ffs_data;
3489         int ret;
3490
3491         /*
3492          * Legacy gadget triggers binding in functionfs_ready_callback,
3493          * which already uses locking; taking the same lock here would
3494          * cause a deadlock.
3495          *
3496          * Configfs-enabled gadgets however do need ffs_dev_lock.
3497          */
3498         if (!ffs_opts->no_configfs)
3499                 ffs_dev_lock();
3500         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3501         ffs_data = ffs_opts->dev->ffs_data;
3502         if (!ffs_opts->no_configfs)
3503                 ffs_dev_unlock();
3504         if (ret)
3505                 return ERR_PTR(ret);
3506
3507         func->ffs = ffs_data;
3508         func->conf = c;
3509         func->gadget = c->cdev->gadget;
3510
3511         /*
3512          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3513          * configurations are bound in sequence with list_for_each_entry,
3514          * in each configuration its functions are bound in sequence
3515          * with list_for_each_entry, so we assume no race condition
3516          * with regard to ffs_opts->bound access
3517          */
3518         if (!ffs_opts->refcnt) {
3519                 ret = functionfs_bind(func->ffs, c->cdev);
3520                 if (ret)
3521                         return ERR_PTR(ret);
3522         }
3523         ffs_opts->refcnt++;
3524         func->function.strings = func->ffs->stringtabs;
3525
3526         return ffs_opts;
3527 }
3528
3529 static int _ffs_func_bind(struct usb_configuration *c,
3530                           struct usb_function *f)
3531 {
3532         struct ffs_function *func = ffs_func_from_usb(f);
3533         struct ffs_data *ffs = func->ffs;
3534
3535         const int full = !!func->ffs->fs_descs_count;
3536         const int high = !!func->ffs->hs_descs_count;
3537         const int super = !!func->ffs->ss_descs_count;
3538
3539         int fs_len, hs_len, ss_len, ret, i;
3540         struct ffs_ep *eps_ptr;
3541
3542         /* Make it a single chunk, less management later on */
3543         vla_group(d);
3544         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3545         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3546                 full ? ffs->fs_descs_count + 1 : 0);
3547         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3548                 high ? ffs->hs_descs_count + 1 : 0);
3549         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3550                 super ? ffs->ss_descs_count + 1 : 0);
3551         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3552         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3553                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3554         vla_item_with_sz(d, char[16], ext_compat,
3555                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3556         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3557                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3558         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3559                          ffs->ms_os_descs_ext_prop_count);
3560         vla_item_with_sz(d, char, ext_prop_name,
3561                          ffs->ms_os_descs_ext_prop_name_len);
3562         vla_item_with_sz(d, char, ext_prop_data,
3563                          ffs->ms_os_descs_ext_prop_data_len);
3564         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3565         char *vlabuf;
3566
3567         /* Has descriptors only for speeds gadget does not support */
3568         if (!(full | high | super))
3569                 return -ENOTSUPP;
3570
3571         /* Allocate a single chunk, less management later on */
3572         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3573         if (!vlabuf)
3574                 return -ENOMEM;
3575
3576         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3577         ffs->ms_os_descs_ext_prop_name_avail =
3578                 vla_ptr(vlabuf, d, ext_prop_name);
3579         ffs->ms_os_descs_ext_prop_data_avail =
3580                 vla_ptr(vlabuf, d, ext_prop_data);
3581
3582         /* Copy descriptors  */
3583         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3584                ffs->raw_descs_length);
3585
3586         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3587         eps_ptr = vla_ptr(vlabuf, d, eps);
3588         for (i = 0; i < ffs->eps_count; i++)
3589                 eps_ptr[i].num = -1;
3590
3591         /* Save pointers
3592          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3593         */
3594         func->eps             = vla_ptr(vlabuf, d, eps);
3595         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3596
3597         /*
3598          * Go through all the endpoint descriptors and allocate
3599          * endpoints first, so that later we can rewrite the endpoint
3600          * numbers without worrying that it may be described later on.
3601          */
3602         if (full) {
3603                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3604                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3605                                       vla_ptr(vlabuf, d, raw_descs),
3606                                       d_raw_descs__sz,
3607                                       __ffs_func_bind_do_descs, func);
3608                 if (fs_len < 0) {
3609                         ret = fs_len;
3610                         goto error;
3611                 }
3612         } else {
3613                 fs_len = 0;
3614         }
3615
3616         if (high) {
3617                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3618                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3619                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3620                                       d_raw_descs__sz - fs_len,
3621                                       __ffs_func_bind_do_descs, func);
3622                 if (hs_len < 0) {
3623                         ret = hs_len;
3624                         goto error;
3625                 }
3626         } else {
3627                 hs_len = 0;
3628         }
3629
3630         if (super) {
3631                 func->function.ss_descriptors = func->function.ssp_descriptors =
3632                         vla_ptr(vlabuf, d, ss_descs);
3633                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3634                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3635                                 d_raw_descs__sz - fs_len - hs_len,
3636                                 __ffs_func_bind_do_descs, func);
3637                 if (ss_len < 0) {
3638                         ret = ss_len;
3639                         goto error;
3640                 }
3641         } else {
3642                 ss_len = 0;
3643         }
3644
3645         /*
3646          * Now handle interface numbers allocation and interface and
3647          * endpoint numbers rewriting.  We can do that in one go
3648          * now.
3649          */
3650         ret = ffs_do_descs(ffs->fs_descs_count +
3651                            (high ? ffs->hs_descs_count : 0) +
3652                            (super ? ffs->ss_descs_count : 0),
3653                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3654                            __ffs_func_bind_do_nums, func);
3655         if (ret < 0)
3656                 goto error;
3657
3658         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3659         if (c->cdev->use_os_string) {
3660                 for (i = 0; i < ffs->interfaces_count; ++i) {
3661                         struct usb_os_desc *desc;
3662
3663                         desc = func->function.os_desc_table[i].os_desc =
3664                                 vla_ptr(vlabuf, d, os_desc) +
3665                                 i * sizeof(struct usb_os_desc);
3666                         desc->ext_compat_id =
3667                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3668                         INIT_LIST_HEAD(&desc->ext_prop);
3669                 }
3670                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3671                                       vla_ptr(vlabuf, d, raw_descs) +
3672                                       fs_len + hs_len + ss_len,
3673                                       d_raw_descs__sz - fs_len - hs_len -
3674                                       ss_len,
3675                                       __ffs_func_bind_do_os_desc, func);
3676                 if (ret < 0)
3677                         goto error;
3678         }
3679         func->function.os_desc_n =
3680                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3681
3682         /* And we're done */
3683         ffs_event_add(ffs, FUNCTIONFS_BIND);
3684         return 0;
3685
3686 error:
3687         /* XXX Do we need to release all claimed endpoints here? */
3688         return ret;
3689 }
3690
3691 static int ffs_func_bind(struct usb_configuration *c,
3692                          struct usb_function *f)
3693 {
3694         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3695         struct ffs_function *func = ffs_func_from_usb(f);
3696         int ret;
3697
3698         if (IS_ERR(ffs_opts))
3699                 return PTR_ERR(ffs_opts);
3700
3701         ret = _ffs_func_bind(c, f);
3702         if (ret && !--ffs_opts->refcnt)
3703                 functionfs_unbind(func->ffs);
3704
3705         return ret;
3706 }
3707
3708
3709 /* Other USB function hooks *************************************************/
3710
3711 static void ffs_reset_work(struct work_struct *work)
3712 {
3713         struct ffs_data *ffs = container_of(work,
3714                 struct ffs_data, reset_work);
3715         ffs_data_reset(ffs);
3716 }
3717
3718 static int ffs_func_get_alt(struct usb_function *f,
3719                             unsigned int interface)
3720 {
3721         struct ffs_function *func = ffs_func_from_usb(f);
3722         int intf = ffs_func_revmap_intf(func, interface);
3723
3724         return (intf < 0) ? intf : func->cur_alt[interface];
3725 }
3726
3727 static int ffs_func_set_alt(struct usb_function *f,
3728                             unsigned interface, unsigned alt)
3729 {
3730         struct ffs_function *func = ffs_func_from_usb(f);
3731         struct ffs_data *ffs = func->ffs;
3732         int ret = 0, intf;
3733
3734         if (alt > MAX_ALT_SETTINGS)
3735                 return -EINVAL;
3736
3737         if (alt != (unsigned)-1) {
3738                 intf = ffs_func_revmap_intf(func, interface);
3739                 if (intf < 0)
3740                         return intf;
3741         }
3742
3743         if (ffs->func)
3744                 ffs_func_eps_disable(ffs->func);
3745
3746         if (ffs->state == FFS_DEACTIVATED) {
3747                 ffs->state = FFS_CLOSING;
3748                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3749                 schedule_work(&ffs->reset_work);
3750                 return -ENODEV;
3751         }
3752
3753         if (ffs->state != FFS_ACTIVE)
3754                 return -ENODEV;
3755
3756         if (alt == (unsigned)-1) {
3757                 ffs->func = NULL;
3758                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3759                 return 0;
3760         }
3761
3762         ffs->func = func;
3763         ret = ffs_func_eps_enable(func);
3764         if (ret >= 0) {
3765                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3766                 func->cur_alt[interface] = alt;
3767         }
3768         return ret;
3769 }
3770
3771 static void ffs_func_disable(struct usb_function *f)
3772 {
3773         ffs_func_set_alt(f, 0, (unsigned)-1);
3774 }
3775
3776 static int ffs_func_setup(struct usb_function *f,
3777                           const struct usb_ctrlrequest *creq)
3778 {
3779         struct ffs_function *func = ffs_func_from_usb(f);
3780         struct ffs_data *ffs = func->ffs;
3781         unsigned long flags;
3782         int ret;
3783
3784         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3785         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3786         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3787         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3788         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3789
3790         /*
3791          * Most requests directed to interface go through here
3792          * (notable exceptions are set/get interface) so we need to
3793          * handle them.  All other either handled by composite or
3794          * passed to usb_configuration->setup() (if one is set).  No
3795          * matter, we will handle requests directed to endpoint here
3796          * as well (as it's straightforward).  Other request recipient
3797          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3798          * is being used.
3799          */
3800         if (ffs->state != FFS_ACTIVE)
3801                 return -ENODEV;
3802
3803         switch (creq->bRequestType & USB_RECIP_MASK) {
3804         case USB_RECIP_INTERFACE:
3805                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3806                 if (ret < 0)
3807                         return ret;
3808                 break;
3809
3810         case USB_RECIP_ENDPOINT:
3811                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3812                 if (ret < 0)
3813                         return ret;
3814                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3815                         ret = func->ffs->eps_addrmap[ret];
3816                 break;
3817
3818         default:
3819                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3820                         ret = le16_to_cpu(creq->wIndex);
3821                 else
3822                         return -EOPNOTSUPP;
3823         }
3824
3825         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3826         ffs->ev.setup = *creq;
3827         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3828         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3829         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3830
3831         return ffs->ev.setup.wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3832 }
3833
3834 static bool ffs_func_req_match(struct usb_function *f,
3835                                const struct usb_ctrlrequest *creq,
3836                                bool config0)
3837 {
3838         struct ffs_function *func = ffs_func_from_usb(f);
3839
3840         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3841                 return false;
3842
3843         switch (creq->bRequestType & USB_RECIP_MASK) {
3844         case USB_RECIP_INTERFACE:
3845                 return (ffs_func_revmap_intf(func,
3846                                              le16_to_cpu(creq->wIndex)) >= 0);
3847         case USB_RECIP_ENDPOINT:
3848                 return (ffs_func_revmap_ep(func,
3849                                            le16_to_cpu(creq->wIndex)) >= 0);
3850         default:
3851                 return (bool) (func->ffs->user_flags &
3852                                FUNCTIONFS_ALL_CTRL_RECIP);
3853         }
3854 }
3855
3856 static void ffs_func_suspend(struct usb_function *f)
3857 {
3858         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3859 }
3860
3861 static void ffs_func_resume(struct usb_function *f)
3862 {
3863         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3864 }
3865
3866
3867 /* Endpoint and interface numbers reverse mapping ***************************/
3868
3869 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3870 {
3871         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3872         return num ? num : -EDOM;
3873 }
3874
3875 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3876 {
3877         short *nums = func->interfaces_nums;
3878         unsigned count = func->ffs->interfaces_count;
3879
3880         for (; count; --count, ++nums) {
3881                 if (*nums >= 0 && *nums == intf)
3882                         return nums - func->interfaces_nums;
3883         }
3884
3885         return -EDOM;
3886 }
3887
3888
3889 /* Devices management *******************************************************/
3890
3891 static LIST_HEAD(ffs_devices);
3892
3893 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3894 {
3895         struct ffs_dev *dev;
3896
3897         if (!name)
3898                 return NULL;
3899
3900         list_for_each_entry(dev, &ffs_devices, entry) {
3901                 if (strcmp(dev->name, name) == 0)
3902                         return dev;
3903         }
3904
3905         return NULL;
3906 }
3907
3908 /*
3909  * ffs_lock must be taken by the caller of this function
3910  */
3911 static struct ffs_dev *_ffs_get_single_dev(void)
3912 {
3913         struct ffs_dev *dev;
3914
3915         if (list_is_singular(&ffs_devices)) {
3916                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3917                 if (dev->single)
3918                         return dev;
3919         }
3920
3921         return NULL;
3922 }
3923
3924 /*
3925  * ffs_lock must be taken by the caller of this function
3926  */
3927 static struct ffs_dev *_ffs_find_dev(const char *name)
3928 {
3929         struct ffs_dev *dev;
3930
3931         dev = _ffs_get_single_dev();
3932         if (dev)
3933                 return dev;
3934
3935         return _ffs_do_find_dev(name);
3936 }
3937
3938 /* Configfs support *********************************************************/
3939
3940 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3941 {
3942         return container_of(to_config_group(item), struct f_fs_opts,
3943                             func_inst.group);
3944 }
3945
3946 static ssize_t f_fs_opts_ready_show(struct config_item *item, char *page)
3947 {
3948         struct f_fs_opts *opts = to_ffs_opts(item);
3949         int ready;
3950
3951         ffs_dev_lock();
3952         ready = opts->dev->desc_ready;
3953         ffs_dev_unlock();
3954
3955         return sprintf(page, "%d\n", ready);
3956 }
3957
3958 CONFIGFS_ATTR_RO(f_fs_opts_, ready);
3959
3960 static struct configfs_attribute *ffs_attrs[] = {
3961         &f_fs_opts_attr_ready,
3962         NULL,
3963 };
3964
3965 static void ffs_attr_release(struct config_item *item)
3966 {
3967         struct f_fs_opts *opts = to_ffs_opts(item);
3968
3969         usb_put_function_instance(&opts->func_inst);
3970 }
3971
3972 static struct configfs_item_operations ffs_item_ops = {
3973         .release        = ffs_attr_release,
3974 };
3975
3976 static const struct config_item_type ffs_func_type = {
3977         .ct_item_ops    = &ffs_item_ops,
3978         .ct_attrs       = ffs_attrs,
3979         .ct_owner       = THIS_MODULE,
3980 };
3981
3982
3983 /* Function registration interface ******************************************/
3984
3985 static void ffs_free_inst(struct usb_function_instance *f)
3986 {
3987         struct f_fs_opts *opts;
3988
3989         opts = to_f_fs_opts(f);
3990         ffs_release_dev(opts->dev);
3991         ffs_dev_lock();
3992         _ffs_free_dev(opts->dev);
3993         ffs_dev_unlock();
3994         kfree(opts);
3995 }
3996
3997 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3998 {
3999         if (strlen(name) >= sizeof_field(struct ffs_dev, name))
4000                 return -ENAMETOOLONG;
4001         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
4002 }
4003
4004 static struct usb_function_instance *ffs_alloc_inst(void)
4005 {
4006         struct f_fs_opts *opts;
4007         struct ffs_dev *dev;
4008
4009         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
4010         if (!opts)
4011                 return ERR_PTR(-ENOMEM);
4012
4013         opts->func_inst.set_inst_name = ffs_set_inst_name;
4014         opts->func_inst.free_func_inst = ffs_free_inst;
4015         ffs_dev_lock();
4016         dev = _ffs_alloc_dev();
4017         ffs_dev_unlock();
4018         if (IS_ERR(dev)) {
4019                 kfree(opts);
4020                 return ERR_CAST(dev);
4021         }
4022         opts->dev = dev;
4023         dev->opts = opts;
4024
4025         config_group_init_type_name(&opts->func_inst.group, "",
4026                                     &ffs_func_type);
4027         return &opts->func_inst;
4028 }
4029
4030 static void ffs_free(struct usb_function *f)
4031 {
4032         kfree(ffs_func_from_usb(f));
4033 }
4034
4035 static void ffs_func_unbind(struct usb_configuration *c,
4036                             struct usb_function *f)
4037 {
4038         struct ffs_function *func = ffs_func_from_usb(f);
4039         struct ffs_data *ffs = func->ffs;
4040         struct f_fs_opts *opts =
4041                 container_of(f->fi, struct f_fs_opts, func_inst);
4042         struct ffs_ep *ep = func->eps;
4043         unsigned count = ffs->eps_count;
4044         unsigned long flags;
4045
4046         if (ffs->func == func) {
4047                 ffs_func_eps_disable(func);
4048                 ffs->func = NULL;
4049         }
4050
4051         /* Drain any pending AIO completions */
4052         drain_workqueue(ffs->io_completion_wq);
4053
4054         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
4055         if (!--opts->refcnt)
4056                 functionfs_unbind(ffs);
4057
4058         /* cleanup after autoconfig */
4059         spin_lock_irqsave(&func->ffs->eps_lock, flags);
4060         while (count--) {
4061                 if (ep->ep && ep->req)
4062                         usb_ep_free_request(ep->ep, ep->req);
4063                 ep->req = NULL;
4064                 ++ep;
4065         }
4066         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
4067         kfree(func->eps);
4068         func->eps = NULL;
4069         /*
4070          * eps, descriptors and interfaces_nums are allocated in the
4071          * same chunk so only one free is required.
4072          */
4073         func->function.fs_descriptors = NULL;
4074         func->function.hs_descriptors = NULL;
4075         func->function.ss_descriptors = NULL;
4076         func->function.ssp_descriptors = NULL;
4077         func->interfaces_nums = NULL;
4078
4079 }
4080
4081 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
4082 {
4083         struct ffs_function *func;
4084
4085         func = kzalloc(sizeof(*func), GFP_KERNEL);
4086         if (!func)
4087                 return ERR_PTR(-ENOMEM);
4088
4089         func->function.name    = "Function FS Gadget";
4090
4091         func->function.bind    = ffs_func_bind;
4092         func->function.unbind  = ffs_func_unbind;
4093         func->function.set_alt = ffs_func_set_alt;
4094         func->function.get_alt = ffs_func_get_alt;
4095         func->function.disable = ffs_func_disable;
4096         func->function.setup   = ffs_func_setup;
4097         func->function.req_match = ffs_func_req_match;
4098         func->function.suspend = ffs_func_suspend;
4099         func->function.resume  = ffs_func_resume;
4100         func->function.free_func = ffs_free;
4101
4102         return &func->function;
4103 }
4104
4105 /*
4106  * ffs_lock must be taken by the caller of this function
4107  */
4108 static struct ffs_dev *_ffs_alloc_dev(void)
4109 {
4110         struct ffs_dev *dev;
4111         int ret;
4112
4113         if (_ffs_get_single_dev())
4114                         return ERR_PTR(-EBUSY);
4115
4116         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4117         if (!dev)
4118                 return ERR_PTR(-ENOMEM);
4119
4120         if (list_empty(&ffs_devices)) {
4121                 ret = functionfs_init();
4122                 if (ret) {
4123                         kfree(dev);
4124                         return ERR_PTR(ret);
4125                 }
4126         }
4127
4128         list_add(&dev->entry, &ffs_devices);
4129
4130         return dev;
4131 }
4132
4133 int ffs_name_dev(struct ffs_dev *dev, const char *name)
4134 {
4135         struct ffs_dev *existing;
4136         int ret = 0;
4137
4138         ffs_dev_lock();
4139
4140         existing = _ffs_do_find_dev(name);
4141         if (!existing)
4142                 strscpy(dev->name, name, ARRAY_SIZE(dev->name));
4143         else if (existing != dev)
4144                 ret = -EBUSY;
4145
4146         ffs_dev_unlock();
4147
4148         return ret;
4149 }
4150 EXPORT_SYMBOL_GPL(ffs_name_dev);
4151
4152 int ffs_single_dev(struct ffs_dev *dev)
4153 {
4154         int ret;
4155
4156         ret = 0;
4157         ffs_dev_lock();
4158
4159         if (!list_is_singular(&ffs_devices))
4160                 ret = -EBUSY;
4161         else
4162                 dev->single = true;
4163
4164         ffs_dev_unlock();
4165         return ret;
4166 }
4167 EXPORT_SYMBOL_GPL(ffs_single_dev);
4168
4169 /*
4170  * ffs_lock must be taken by the caller of this function
4171  */
4172 static void _ffs_free_dev(struct ffs_dev *dev)
4173 {
4174         list_del(&dev->entry);
4175
4176         kfree(dev);
4177         if (list_empty(&ffs_devices))
4178                 functionfs_cleanup();
4179 }
4180
4181 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data)
4182 {
4183         int ret = 0;
4184         struct ffs_dev *ffs_dev;
4185
4186         ffs_dev_lock();
4187
4188         ffs_dev = _ffs_find_dev(dev_name);
4189         if (!ffs_dev) {
4190                 ret = -ENOENT;
4191         } else if (ffs_dev->mounted) {
4192                 ret = -EBUSY;
4193         } else if (ffs_dev->ffs_acquire_dev_callback &&
4194                    ffs_dev->ffs_acquire_dev_callback(ffs_dev)) {
4195                 ret = -ENOENT;
4196         } else {
4197                 ffs_dev->mounted = true;
4198                 ffs_dev->ffs_data = ffs_data;
4199                 ffs_data->private_data = ffs_dev;
4200         }
4201
4202         ffs_dev_unlock();
4203         return ret;
4204 }
4205
4206 static void ffs_release_dev(struct ffs_dev *ffs_dev)
4207 {
4208         ffs_dev_lock();
4209
4210         if (ffs_dev && ffs_dev->mounted) {
4211                 ffs_dev->mounted = false;
4212                 if (ffs_dev->ffs_data) {
4213                         ffs_dev->ffs_data->private_data = NULL;
4214                         ffs_dev->ffs_data = NULL;
4215                 }
4216
4217                 if (ffs_dev->ffs_release_dev_callback)
4218                         ffs_dev->ffs_release_dev_callback(ffs_dev);
4219         }
4220
4221         ffs_dev_unlock();
4222 }
4223
4224 static int ffs_ready(struct ffs_data *ffs)
4225 {
4226         struct ffs_dev *ffs_obj;
4227         int ret = 0;
4228
4229         ffs_dev_lock();
4230
4231         ffs_obj = ffs->private_data;
4232         if (!ffs_obj) {
4233                 ret = -EINVAL;
4234                 goto done;
4235         }
4236         if (WARN_ON(ffs_obj->desc_ready)) {
4237                 ret = -EBUSY;
4238                 goto done;
4239         }
4240
4241         ffs_obj->desc_ready = true;
4242
4243         if (ffs_obj->ffs_ready_callback) {
4244                 ret = ffs_obj->ffs_ready_callback(ffs);
4245                 if (ret)
4246                         goto done;
4247         }
4248
4249         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
4250 done:
4251         ffs_dev_unlock();
4252         return ret;
4253 }
4254
4255 static void ffs_closed(struct ffs_data *ffs)
4256 {
4257         struct ffs_dev *ffs_obj;
4258         struct f_fs_opts *opts;
4259         struct config_item *ci;
4260
4261         ffs_dev_lock();
4262
4263         ffs_obj = ffs->private_data;
4264         if (!ffs_obj)
4265                 goto done;
4266
4267         ffs_obj->desc_ready = false;
4268
4269         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
4270             ffs_obj->ffs_closed_callback)
4271                 ffs_obj->ffs_closed_callback(ffs);
4272
4273         if (ffs_obj->opts)
4274                 opts = ffs_obj->opts;
4275         else
4276                 goto done;
4277
4278         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
4279             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
4280                 goto done;
4281
4282         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
4283         ffs_dev_unlock();
4284
4285         if (test_bit(FFS_FL_BOUND, &ffs->flags))
4286                 unregister_gadget_item(ci);
4287         return;
4288 done:
4289         ffs_dev_unlock();
4290 }
4291
4292 /* Misc helper functions ****************************************************/
4293
4294 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
4295 {
4296         return nonblock
4297                 ? mutex_trylock(mutex) ? 0 : -EAGAIN
4298                 : mutex_lock_interruptible(mutex);
4299 }
4300
4301 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
4302 {
4303         char *data;
4304
4305         if (!len)
4306                 return NULL;
4307
4308         data = memdup_user(buf, len);
4309         if (IS_ERR(data))
4310                 return data;
4311
4312         pr_vdebug("Buffer from user space:\n");
4313         ffs_dump_mem("", data, len);
4314
4315         return data;
4316 }
4317
4318 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
4319 MODULE_LICENSE("GPL");
4320 MODULE_AUTHOR("Michal Nazarewicz");