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