inode.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * inode.c -- user mode filesystem api for usb gadget controllers
   4 *
   5 * Copyright (C) 2003-2004 David Brownell
   6 * Copyright (C) 2003 Agilent Technologies
   7 */
   8
   9
  10/* #define VERBOSE_DEBUG */
  11
  12#include <linux/init.h>
  13#include <linux/module.h>
  14#include <linux/fs.h>
  15#include <linux/fs_context.h>
  16#include <linux/pagemap.h>
  17#include <linux/uts.h>
  18#include <linux/wait.h>
  19#include <linux/compiler.h>
  20#include <linux/uaccess.h>
  21#include <linux/sched.h>
  22#include <linux/slab.h>
  23#include <linux/string_choices.h>
  24#include <linux/poll.h>
  25#include <linux/kthread.h>
  26#include <linux/aio.h>
  27#include <linux/uio.h>
  28#include <linux/refcount.h>
  29#include <linux/delay.h>
  30#include <linux/device.h>
  31#include <linux/moduleparam.h>
  32
  33#include <linux/usb/gadgetfs.h>
  34#include <linux/usb/gadget.h>
  35#include <linux/usb/composite.h> /* for USB_GADGET_DELAYED_STATUS */
  36
  37/* Undef helpers from linux/usb/composite.h as gadgetfs redefines them */
  38#undef DBG
  39#undef ERROR
  40#undef INFO
  41
  42
  43/*
  44 * The gadgetfs API maps each endpoint to a file descriptor so that you
  45 * can use standard synchronous read/write calls for I/O.  There's some
  46 * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
  47 * drivers show how this works in practice.  You can also use AIO to
  48 * eliminate I/O gaps between requests, to help when streaming data.
  49 *
  50 * Key parts that must be USB-specific are protocols defining how the
  51 * read/write operations relate to the hardware state machines.  There
  52 * are two types of files.  One type is for the device, implementing ep0.
  53 * The other type is for each IN or OUT endpoint.  In both cases, the
  54 * user mode driver must configure the hardware before using it.
  55 *
  56 * - First, dev_config() is called when /dev/gadget/$CHIP is configured
  57 *   (by writing configuration and device descriptors).  Afterwards it
  58 *   may serve as a source of device events, used to handle all control
  59 *   requests other than basic enumeration.
  60 *
  61 * - Then, after a SET_CONFIGURATION control request, ep_config() is
  62 *   called when each /dev/gadget/ep* file is configured (by writing
  63 *   endpoint descriptors).  Afterwards these files are used to write()
  64 *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
  65 *   direction" request is issued (like reading an IN endpoint).
  66 *
  67 * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  68 * not possible on all hardware.  For example, precise fault handling with
  69 * respect to data left in endpoint fifos after aborted operations; or
  70 * selective clearing of endpoint halts, to implement SET_INTERFACE.
  71 */
  72
  73#define	DRIVER_DESC	"USB Gadget filesystem"
  74#define	DRIVER_VERSION	"24 Aug 2004"
  75
  76static const char driver_desc [] = DRIVER_DESC;
  77static const char shortname [] = "gadgetfs";
  78
  79MODULE_DESCRIPTION (DRIVER_DESC);
  80MODULE_AUTHOR ("David Brownell");
  81MODULE_LICENSE ("GPL");
  82
  83static int ep_open(struct inode *, struct file *);
  84
  85
  86/*----------------------------------------------------------------------*/
  87
  88#define GADGETFS_MAGIC		0xaee71ee7
  89
  90/* /dev/gadget/$CHIP represents ep0 and the whole device */
  91enum ep0_state {
  92	/* DISABLED is the initial state. */
  93	STATE_DEV_DISABLED = 0,
  94
  95	/* Only one open() of /dev/gadget/$CHIP; only one file tracks
  96	 * ep0/device i/o modes and binding to the controller.  Driver
  97	 * must always write descriptors to initialize the device, then
  98	 * the device becomes UNCONNECTED until enumeration.
  99	 */
 100	STATE_DEV_OPENED,
 101
 102	/* From then on, ep0 fd is in either of two basic modes:
 103	 * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
 104	 * - SETUP: read/write will transfer control data and succeed;
 105	 *   or if "wrong direction", performs protocol stall
 106	 */
 107	STATE_DEV_UNCONNECTED,
 108	STATE_DEV_CONNECTED,
 109	STATE_DEV_SETUP,
 110
 111	/* UNBOUND means the driver closed ep0, so the device won't be
 112	 * accessible again (DEV_DISABLED) until all fds are closed.
 113	 */
 114	STATE_DEV_UNBOUND,
 115};
 116
 117/* enough for the whole queue: most events invalidate others */
 118#define	N_EVENT			5
 119
 120#define RBUF_SIZE		256
 121
 122struct dev_data {
 123	spinlock_t			lock;
 124	refcount_t			count;
 125	int				udc_usage;
 126	enum ep0_state			state;		/* P: lock */
 127	struct usb_gadgetfs_event	event [N_EVENT];
 128	unsigned			ev_next;
 129	struct fasync_struct		*fasync;
 130	u8				current_config;
 131
 132	/* drivers reading ep0 MUST handle control requests (SETUP)
 133	 * reported that way; else the host will time out.
 134	 */
 135	unsigned			usermode_setup : 1,
 136					setup_in : 1,
 137					setup_can_stall : 1,
 138					setup_out_ready : 1,
 139					setup_out_error : 1,
 140					setup_abort : 1,
 141					gadget_registered : 1;
 142	unsigned			setup_wLength;
 143
 144	/* the rest is basically write-once */
 145	struct usb_config_descriptor	*config, *hs_config;
 146	struct usb_device_descriptor	*dev;
 147	struct usb_request		*req;
 148	struct usb_gadget		*gadget;
 149	struct list_head		epfiles;
 150	void				*buf;
 151	wait_queue_head_t		wait;
 152	struct super_block		*sb;
 153
 154	/* except this scratch i/o buffer for ep0 */
 155	u8				rbuf[RBUF_SIZE];
 156};
 157
 158static inline void get_dev (struct dev_data *data)
 159{
 160	refcount_inc (&data->count);
 161}
 162
 163static void put_dev (struct dev_data *data)
 164{
 165	if (likely (!refcount_dec_and_test (&data->count)))
 166		return;
 167	/* needs no more cleanup */
 168	BUG_ON (waitqueue_active (&data->wait));
 169	kfree (data);
 170}
 171
 172static struct dev_data *dev_new (void)
 173{
 174	struct dev_data		*dev;
 175
 176	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 177	if (!dev)
 178		return NULL;
 179	dev->state = STATE_DEV_DISABLED;
 180	refcount_set (&dev->count, 1);
 181	spin_lock_init (&dev->lock);
 182	INIT_LIST_HEAD (&dev->epfiles);
 183	init_waitqueue_head (&dev->wait);
 184	return dev;
 185}
 186
 187/*----------------------------------------------------------------------*/
 188
 189/* other /dev/gadget/$ENDPOINT files represent endpoints */
 190enum ep_state {
 191	STATE_EP_DISABLED = 0,
 192	STATE_EP_READY,
 193	STATE_EP_ENABLED,
 194	STATE_EP_UNBOUND,
 195};
 196
 197struct ep_data {
 198	struct mutex			lock;
 199	enum ep_state			state;
 200	refcount_t			count;
 201	struct dev_data			*dev;
 202	/* must hold dev->lock before accessing ep or req */
 203	struct usb_ep			*ep;
 204	struct usb_request		*req;
 205	ssize_t				status;
 206	char				name [16];
 207	struct usb_endpoint_descriptor	desc, hs_desc;
 208	struct list_head		epfiles;
 209	wait_queue_head_t		wait;
 210};
 211
 212static inline void get_ep (struct ep_data *data)
 213{
 214	refcount_inc (&data->count);
 215}
 216
 217static void put_ep (struct ep_data *data)
 218{
 219	if (likely (!refcount_dec_and_test (&data->count)))
 220		return;
 221	put_dev (data->dev);
 222	/* needs no more cleanup */
 223	BUG_ON (!list_empty (&data->epfiles));
 224	BUG_ON (waitqueue_active (&data->wait));
 225	kfree (data);
 226}
 227
 228/*----------------------------------------------------------------------*/
 229
 230/* most "how to use the hardware" policy choices are in userspace:
 231 * mapping endpoint roles (which the driver needs) to the capabilities
 232 * which the usb controller has.  most of those capabilities are exposed
 233 * implicitly, starting with the driver name and then endpoint names.
 234 */
 235
 236static const char *CHIP;
 237static DEFINE_MUTEX(sb_mutex);		/* Serialize superblock operations */
 238
 239/*----------------------------------------------------------------------*/
 240
 241/* NOTE:  don't use dev_printk calls before binding to the gadget
 242 * at the end of ep0 configuration, or after unbind.
 243 */
 244
 245/* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
 246#define xprintk(d,level,fmt,args...) \
 247	printk(level "%s: " fmt , shortname , ## args)
 248
 249#ifdef DEBUG
 250#define DBG(dev,fmt,args...) \
 251	xprintk(dev , KERN_DEBUG , fmt , ## args)
 252#else
 253#define DBG(dev,fmt,args...) \
 254	do { } while (0)
 255#endif /* DEBUG */
 256
 257#ifdef VERBOSE_DEBUG
 258#define VDEBUG	DBG
 259#else
 260#define VDEBUG(dev,fmt,args...) \
 261	do { } while (0)
 262#endif /* DEBUG */
 263
 264#define ERROR(dev,fmt,args...) \
 265	xprintk(dev , KERN_ERR , fmt , ## args)
 266#define INFO(dev,fmt,args...) \
 267	xprintk(dev , KERN_INFO , fmt , ## args)
 268
 269
 270/*----------------------------------------------------------------------*/
 271
 272/* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
 273 *
 274 * After opening, configure non-control endpoints.  Then use normal
 275 * stream read() and write() requests; and maybe ioctl() to get more
 276 * precise FIFO status when recovering from cancellation.
 277 */
 278
 279static void epio_complete (struct usb_ep *ep, struct usb_request *req)
 280{
 281	struct ep_data	*epdata = ep->driver_data;
 282
 283	if (!req->context)
 284		return;
 285	if (req->status)
 286		epdata->status = req->status;
 287	else
 288		epdata->status = req->actual;
 289	complete ((struct completion *)req->context);
 290}
 291
 292/* tasklock endpoint, returning when it's connected.
 293 * still need dev->lock to use epdata->ep.
 294 */
 295static int
 296get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write)
 297{
 298	int	val;
 299
 300	if (f_flags & O_NONBLOCK) {
 301		if (!mutex_trylock(&epdata->lock))
 302			goto nonblock;
 303		if (epdata->state != STATE_EP_ENABLED &&
 304		    (!is_write || epdata->state != STATE_EP_READY)) {
 305			mutex_unlock(&epdata->lock);
 306nonblock:
 307			val = -EAGAIN;
 308		} else
 309			val = 0;
 310		return val;
 311	}
 312
 313	val = mutex_lock_interruptible(&epdata->lock);
 314	if (val < 0)
 315		return val;
 316
 317	switch (epdata->state) {
 318	case STATE_EP_ENABLED:
 319		return 0;
 320	case STATE_EP_READY:			/* not configured yet */
 321		if (is_write)
 322			return 0;
 323		fallthrough;
 324	case STATE_EP_UNBOUND:			/* clean disconnect */
 325		break;
 326	// case STATE_EP_DISABLED:		/* "can't happen" */
 327	default:				/* error! */
 328		pr_debug ("%s: ep %p not available, state %d\n",
 329				shortname, epdata, epdata->state);
 330	}
 331	mutex_unlock(&epdata->lock);
 332	return -ENODEV;
 333}
 334
 335static ssize_t
 336ep_io (struct ep_data *epdata, void *buf, unsigned len)
 337{
 338	DECLARE_COMPLETION_ONSTACK (done);
 339	int value;
 340
 341	spin_lock_irq (&epdata->dev->lock);
 342	if (likely (epdata->ep != NULL)) {
 343		struct usb_request	*req = epdata->req;
 344
 345		req->context = &done;
 346		req->complete = epio_complete;
 347		req->buf = buf;
 348		req->length = len;
 349		value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
 350	} else
 351		value = -ENODEV;
 352	spin_unlock_irq (&epdata->dev->lock);
 353
 354	if (likely (value == 0)) {
 355		value = wait_for_completion_interruptible(&done);
 356		if (value != 0) {
 357			spin_lock_irq (&epdata->dev->lock);
 358			if (likely (epdata->ep != NULL)) {
 359				DBG (epdata->dev, "%s i/o interrupted\n",
 360						epdata->name);
 361				usb_ep_dequeue (epdata->ep, epdata->req);
 362				spin_unlock_irq (&epdata->dev->lock);
 363
 364				wait_for_completion(&done);
 365				if (epdata->status == -ECONNRESET)
 366					epdata->status = -EINTR;
 367			} else {
 368				spin_unlock_irq (&epdata->dev->lock);
 369
 370				DBG (epdata->dev, "endpoint gone\n");
 371				wait_for_completion(&done);
 372				epdata->status = -ENODEV;
 373			}
 374		}
 375		return epdata->status;
 376	}
 377	return value;
 378}
 379
 380static int
 381ep_release (struct inode *inode, struct file *fd)
 382{
 383	struct ep_data		*data = fd->private_data;
 384	int value;
 385
 386	value = mutex_lock_interruptible(&data->lock);
 387	if (value < 0)
 388		return value;
 389
 390	/* clean up if this can be reopened */
 391	if (data->state != STATE_EP_UNBOUND) {
 392		data->state = STATE_EP_DISABLED;
 393		data->desc.bDescriptorType = 0;
 394		data->hs_desc.bDescriptorType = 0;
 395		usb_ep_disable(data->ep);
 396	}
 397	mutex_unlock(&data->lock);
 398	put_ep (data);
 399	return 0;
 400}
 401
 402static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
 403{
 404	struct ep_data		*data = fd->private_data;
 405	int			status;
 406
 407	if ((status = get_ready_ep (fd->f_flags, data, false)) < 0)
 408		return status;
 409
 410	spin_lock_irq (&data->dev->lock);
 411	if (likely (data->ep != NULL)) {
 412		switch (code) {
 413		case GADGETFS_FIFO_STATUS:
 414			status = usb_ep_fifo_status (data->ep);
 415			break;
 416		case GADGETFS_FIFO_FLUSH:
 417			usb_ep_fifo_flush (data->ep);
 418			break;
 419		case GADGETFS_CLEAR_HALT:
 420			status = usb_ep_clear_halt (data->ep);
 421			break;
 422		default:
 423			status = -ENOTTY;
 424		}
 425	} else
 426		status = -ENODEV;
 427	spin_unlock_irq (&data->dev->lock);
 428	mutex_unlock(&data->lock);
 429	return status;
 430}
 431
 432/*----------------------------------------------------------------------*/
 433
 434/* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
 435
 436struct kiocb_priv {
 437	struct usb_request	*req;
 438	struct ep_data		*epdata;
 439	struct kiocb		*iocb;
 440	struct mm_struct	*mm;
 441	struct work_struct	work;
 442	void			*buf;
 443	struct iov_iter		to;
 444	const void		*to_free;
 445	unsigned		actual;
 446};
 447
 448static int ep_aio_cancel(struct kiocb *iocb)
 449{
 450	struct kiocb_priv	*priv = iocb->private;
 451	struct ep_data		*epdata;
 452	int			value;
 453
 454	local_irq_disable();
 455	epdata = priv->epdata;
 456	// spin_lock(&epdata->dev->lock);
 457	if (likely(epdata && epdata->ep && priv->req))
 458		value = usb_ep_dequeue (epdata->ep, priv->req);
 459	else
 460		value = -EINVAL;
 461	// spin_unlock(&epdata->dev->lock);
 462	local_irq_enable();
 463
 464	return value;
 465}
 466
 467static void ep_user_copy_worker(struct work_struct *work)
 468{
 469	struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
 470	struct mm_struct *mm = priv->mm;
 471	struct kiocb *iocb = priv->iocb;
 472	size_t ret;
 473
 474	kthread_use_mm(mm);
 475	ret = copy_to_iter(priv->buf, priv->actual, &priv->to);
 476	kthread_unuse_mm(mm);
 477	if (!ret)
 478		ret = -EFAULT;
 479
 480	/* completing the iocb can drop the ctx and mm, don't touch mm after */
 481	iocb->ki_complete(iocb, ret);
 482
 483	kfree(priv->buf);
 484	kfree(priv->to_free);
 485	kfree(priv);
 486}
 487
 488static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 489{
 490	struct kiocb		*iocb = req->context;
 491	struct kiocb_priv	*priv = iocb->private;
 492	struct ep_data		*epdata = priv->epdata;
 493
 494	/* lock against disconnect (and ideally, cancel) */
 495	spin_lock(&epdata->dev->lock);
 496	priv->req = NULL;
 497	priv->epdata = NULL;
 498
 499	/* if this was a write or a read returning no data then we
 500	 * don't need to copy anything to userspace, so we can
 501	 * complete the aio request immediately.
 502	 */
 503	if (priv->to_free == NULL || unlikely(req->actual == 0)) {
 504		kfree(req->buf);
 505		kfree(priv->to_free);
 506		kfree(priv);
 507		iocb->private = NULL;
 508		iocb->ki_complete(iocb,
 509				req->actual ? req->actual : (long)req->status);
 510	} else {
 511		/* ep_copy_to_user() won't report both; we hide some faults */
 512		if (unlikely(0 != req->status))
 513			DBG(epdata->dev, "%s fault %d len %d\n",
 514				ep->name, req->status, req->actual);
 515
 516		priv->buf = req->buf;
 517		priv->actual = req->actual;
 518		INIT_WORK(&priv->work, ep_user_copy_worker);
 519		schedule_work(&priv->work);
 520	}
 521
 522	usb_ep_free_request(ep, req);
 523	spin_unlock(&epdata->dev->lock);
 524	put_ep(epdata);
 525}
 526
 527static ssize_t ep_aio(struct kiocb *iocb,
 528		      struct kiocb_priv *priv,
 529		      struct ep_data *epdata,
 530		      char *buf,
 531		      size_t len)
 532{
 533	struct usb_request *req;
 534	ssize_t value;
 535
 536	iocb->private = priv;
 537	priv->iocb = iocb;
 538
 539	kiocb_set_cancel_fn(iocb, ep_aio_cancel);
 540	get_ep(epdata);
 541	priv->epdata = epdata;
 542	priv->actual = 0;
 543	priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
 544
 545	/* each kiocb is coupled to one usb_request, but we can't
 546	 * allocate or submit those if the host disconnected.
 547	 */
 548	spin_lock_irq(&epdata->dev->lock);
 549	value = -ENODEV;
 550	if (unlikely(epdata->ep == NULL))
 551		goto fail;
 552
 553	req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 554	value = -ENOMEM;
 555	if (unlikely(!req))
 556		goto fail;
 557
 558	priv->req = req;
 559	req->buf = buf;
 560	req->length = len;
 561	req->complete = ep_aio_complete;
 562	req->context = iocb;
 563	value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 564	if (unlikely(0 != value)) {
 565		usb_ep_free_request(epdata->ep, req);
 566		goto fail;
 567	}
 568	spin_unlock_irq(&epdata->dev->lock);
 569	return -EIOCBQUEUED;
 570
 571fail:
 572	spin_unlock_irq(&epdata->dev->lock);
 573	kfree(priv->to_free);
 574	kfree(priv);
 575	put_ep(epdata);
 576	return value;
 577}
 578
 579static ssize_t
 580ep_read_iter(struct kiocb *iocb, struct iov_iter *to)
 581{
 582	struct file *file = iocb->ki_filp;
 583	struct ep_data *epdata = file->private_data;
 584	size_t len = iov_iter_count(to);
 585	ssize_t value;
 586	char *buf;
 587
 588	if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0)
 589		return value;
 590
 591	/* halt any endpoint by doing a "wrong direction" i/o call */
 592	if (usb_endpoint_dir_in(&epdata->desc)) {
 593		if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 594		    !is_sync_kiocb(iocb)) {
 595			mutex_unlock(&epdata->lock);
 596			return -EINVAL;
 597		}
 598		DBG (epdata->dev, "%s halt\n", epdata->name);
 599		spin_lock_irq(&epdata->dev->lock);
 600		if (likely(epdata->ep != NULL))
 601			usb_ep_set_halt(epdata->ep);
 602		spin_unlock_irq(&epdata->dev->lock);
 603		mutex_unlock(&epdata->lock);
 604		return -EBADMSG;
 605	}
 606
 607	buf = kmalloc(len, GFP_KERNEL);
 608	if (unlikely(!buf)) {
 609		mutex_unlock(&epdata->lock);
 610		return -ENOMEM;
 611	}
 612	if (is_sync_kiocb(iocb)) {
 613		value = ep_io(epdata, buf, len);
 614		if (value >= 0 && (copy_to_iter(buf, value, to) != value))
 615			value = -EFAULT;
 616	} else {
 617		struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 618		value = -ENOMEM;
 619		if (!priv)
 620			goto fail;
 621		priv->to_free = dup_iter(&priv->to, to, GFP_KERNEL);
 622		if (!iter_is_ubuf(&priv->to) && !priv->to_free) {
 623			kfree(priv);
 624			goto fail;
 625		}
 626		value = ep_aio(iocb, priv, epdata, buf, len);
 627		if (value == -EIOCBQUEUED)
 628			buf = NULL;
 629	}
 630fail:
 631	kfree(buf);
 632	mutex_unlock(&epdata->lock);
 633	return value;
 634}
 635
 636static ssize_t ep_config(struct ep_data *, const char *, size_t);
 637
 638static ssize_t
 639ep_write_iter(struct kiocb *iocb, struct iov_iter *from)
 640{
 641	struct file *file = iocb->ki_filp;
 642	struct ep_data *epdata = file->private_data;
 643	size_t len = iov_iter_count(from);
 644	bool configured;
 645	ssize_t value;
 646	char *buf;
 647
 648	if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0)
 649		return value;
 650
 651	configured = epdata->state == STATE_EP_ENABLED;
 652
 653	/* halt any endpoint by doing a "wrong direction" i/o call */
 654	if (configured && !usb_endpoint_dir_in(&epdata->desc)) {
 655		if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 656		    !is_sync_kiocb(iocb)) {
 657			mutex_unlock(&epdata->lock);
 658			return -EINVAL;
 659		}
 660		DBG (epdata->dev, "%s halt\n", epdata->name);
 661		spin_lock_irq(&epdata->dev->lock);
 662		if (likely(epdata->ep != NULL))
 663			usb_ep_set_halt(epdata->ep);
 664		spin_unlock_irq(&epdata->dev->lock);
 665		mutex_unlock(&epdata->lock);
 666		return -EBADMSG;
 667	}
 668
 669	buf = kmalloc(len, GFP_KERNEL);
 670	if (unlikely(!buf)) {
 671		mutex_unlock(&epdata->lock);
 672		return -ENOMEM;
 673	}
 674
 675	if (unlikely(!copy_from_iter_full(buf, len, from))) {
 676		value = -EFAULT;
 677		goto out;
 678	}
 679
 680	if (unlikely(!configured)) {
 681		value = ep_config(epdata, buf, len);
 682	} else if (is_sync_kiocb(iocb)) {
 683		value = ep_io(epdata, buf, len);
 684	} else {
 685		struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 686		value = -ENOMEM;
 687		if (priv) {
 688			value = ep_aio(iocb, priv, epdata, buf, len);
 689			if (value == -EIOCBQUEUED)
 690				buf = NULL;
 691		}
 692	}
 693out:
 694	kfree(buf);
 695	mutex_unlock(&epdata->lock);
 696	return value;
 697}
 698
 699/*----------------------------------------------------------------------*/
 700
 701/* used after endpoint configuration */
 702static const struct file_operations ep_io_operations = {
 703	.owner =	THIS_MODULE,
 704
 705	.open =		ep_open,
 706	.release =	ep_release,
 707	.unlocked_ioctl = ep_ioctl,
 708	.read_iter =	ep_read_iter,
 709	.write_iter =	ep_write_iter,
 710};
 711
 712/* ENDPOINT INITIALIZATION
 713 *
 714 *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 715 *     status = write (fd, descriptors, sizeof descriptors)
 716 *
 717 * That write establishes the endpoint configuration, configuring
 718 * the controller to process bulk, interrupt, or isochronous transfers
 719 * at the right maxpacket size, and so on.
 720 *
 721 * The descriptors are message type 1, identified by a host order u32
 722 * at the beginning of what's written.  Descriptor order is: full/low
 723 * speed descriptor, then optional high speed descriptor.
 724 */
 725static ssize_t
 726ep_config (struct ep_data *data, const char *buf, size_t len)
 727{
 728	struct usb_ep		*ep;
 729	u32			tag;
 730	int			value, length = len;
 731
 732	if (data->state != STATE_EP_READY) {
 733		value = -EL2HLT;
 734		goto fail;
 735	}
 736
 737	value = len;
 738	if (len < USB_DT_ENDPOINT_SIZE + 4)
 739		goto fail0;
 740
 741	/* we might need to change message format someday */
 742	memcpy(&tag, buf, 4);
 743	if (tag != 1) {
 744		DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 745		goto fail0;
 746	}
 747	buf += 4;
 748	len -= 4;
 749
 750	/* NOTE:  audio endpoint extensions not accepted here;
 751	 * just don't include the extra bytes.
 752	 */
 753
 754	/* full/low speed descriptor, then high speed */
 755	memcpy(&data->desc, buf, USB_DT_ENDPOINT_SIZE);
 756	if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 757			|| data->desc.bDescriptorType != USB_DT_ENDPOINT)
 758		goto fail0;
 759	if (len != USB_DT_ENDPOINT_SIZE) {
 760		if (len != 2 * USB_DT_ENDPOINT_SIZE)
 761			goto fail0;
 762		memcpy(&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 763			USB_DT_ENDPOINT_SIZE);
 764		if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 765				|| data->hs_desc.bDescriptorType
 766					!= USB_DT_ENDPOINT) {
 767			DBG(data->dev, "config %s, bad hs length or type\n",
 768					data->name);
 769			goto fail0;
 770		}
 771	}
 772
 773	spin_lock_irq (&data->dev->lock);
 774	if (data->dev->state == STATE_DEV_UNBOUND) {
 775		value = -ENOENT;
 776		goto gone;
 777	} else {
 778		ep = data->ep;
 779		if (ep == NULL) {
 780			value = -ENODEV;
 781			goto gone;
 782		}
 783	}
 784	switch (data->dev->gadget->speed) {
 785	case USB_SPEED_LOW:
 786	case USB_SPEED_FULL:
 787		ep->desc = &data->desc;
 788		break;
 789	case USB_SPEED_HIGH:
 790		/* fails if caller didn't provide that descriptor... */
 791		ep->desc = &data->hs_desc;
 792		break;
 793	default:
 794		DBG(data->dev, "unconnected, %s init abandoned\n",
 795				data->name);
 796		value = -EINVAL;
 797		goto gone;
 798	}
 799	value = usb_ep_enable(ep);
 800	if (value == 0) {
 801		data->state = STATE_EP_ENABLED;
 802		value = length;
 803	}
 804gone:
 805	spin_unlock_irq (&data->dev->lock);
 806	if (value < 0) {
 807fail:
 808		data->desc.bDescriptorType = 0;
 809		data->hs_desc.bDescriptorType = 0;
 810	}
 811	return value;
 812fail0:
 813	value = -EINVAL;
 814	goto fail;
 815}
 816
 817static int
 818ep_open (struct inode *inode, struct file *fd)
 819{
 820	struct ep_data		*data = inode->i_private;
 821	int			value = -EBUSY;
 822
 823	if (mutex_lock_interruptible(&data->lock) != 0)
 824		return -EINTR;
 825	spin_lock_irq (&data->dev->lock);
 826	if (data->dev->state == STATE_DEV_UNBOUND)
 827		value = -ENOENT;
 828	else if (data->state == STATE_EP_DISABLED) {
 829		value = 0;
 830		data->state = STATE_EP_READY;
 831		get_ep (data);
 832		fd->private_data = data;
 833		VDEBUG (data->dev, "%s ready\n", data->name);
 834	} else
 835		DBG (data->dev, "%s state %d\n",
 836			data->name, data->state);
 837	spin_unlock_irq (&data->dev->lock);
 838	mutex_unlock(&data->lock);
 839	return value;
 840}
 841
 842/*----------------------------------------------------------------------*/
 843
 844/* EP0 IMPLEMENTATION can be partly in userspace.
 845 *
 846 * Drivers that use this facility receive various events, including
 847 * control requests the kernel doesn't handle.  Drivers that don't
 848 * use this facility may be too simple-minded for real applications.
 849 */
 850
 851static inline void ep0_readable (struct dev_data *dev)
 852{
 853	wake_up (&dev->wait);
 854	kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 855}
 856
 857static void clean_req (struct usb_ep *ep, struct usb_request *req)
 858{
 859	struct dev_data		*dev = ep->driver_data;
 860
 861	if (req->buf != dev->rbuf) {
 862		kfree(req->buf);
 863		req->buf = dev->rbuf;
 864	}
 865	req->complete = epio_complete;
 866	dev->setup_out_ready = 0;
 867}
 868
 869static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 870{
 871	struct dev_data		*dev = ep->driver_data;
 872	unsigned long		flags;
 873	int			free = 1;
 874
 875	/* for control OUT, data must still get to userspace */
 876	spin_lock_irqsave(&dev->lock, flags);
 877	if (!dev->setup_in) {
 878		dev->setup_out_error = (req->status != 0);
 879		if (!dev->setup_out_error)
 880			free = 0;
 881		dev->setup_out_ready = 1;
 882		ep0_readable (dev);
 883	}
 884
 885	/* clean up as appropriate */
 886	if (free && req->buf != &dev->rbuf)
 887		clean_req (ep, req);
 888	req->complete = epio_complete;
 889	spin_unlock_irqrestore(&dev->lock, flags);
 890}
 891
 892static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 893{
 894	struct dev_data	*dev = ep->driver_data;
 895
 896	if (dev->setup_out_ready) {
 897		DBG (dev, "ep0 request busy!\n");
 898		return -EBUSY;
 899	}
 900	if (len > sizeof (dev->rbuf))
 901		req->buf = kmalloc(len, GFP_ATOMIC);
 902	if (req->buf == NULL) {
 903		req->buf = dev->rbuf;
 904		return -ENOMEM;
 905	}
 906	req->complete = ep0_complete;
 907	req->length = len;
 908	req->zero = 0;
 909	return 0;
 910}
 911
 912static ssize_t
 913ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 914{
 915	struct dev_data			*dev = fd->private_data;
 916	ssize_t				retval;
 917	enum ep0_state			state;
 918
 919	spin_lock_irq (&dev->lock);
 920	if (dev->state <= STATE_DEV_OPENED) {
 921		retval = -EINVAL;
 922		goto done;
 923	}
 924
 925	/* report fd mode change before acting on it */
 926	if (dev->setup_abort) {
 927		dev->setup_abort = 0;
 928		retval = -EIDRM;
 929		goto done;
 930	}
 931
 932	/* control DATA stage */
 933	if ((state = dev->state) == STATE_DEV_SETUP) {
 934
 935		if (dev->setup_in) {		/* stall IN */
 936			VDEBUG(dev, "ep0in stall\n");
 937			(void) usb_ep_set_halt (dev->gadget->ep0);
 938			retval = -EL2HLT;
 939			dev->state = STATE_DEV_CONNECTED;
 940
 941		} else if (len == 0) {		/* ack SET_CONFIGURATION etc */
 942			struct usb_ep		*ep = dev->gadget->ep0;
 943			struct usb_request	*req = dev->req;
 944
 945			if ((retval = setup_req (ep, req, 0)) == 0) {
 946				++dev->udc_usage;
 947				spin_unlock_irq (&dev->lock);
 948				retval = usb_ep_queue (ep, req, GFP_KERNEL);
 949				spin_lock_irq (&dev->lock);
 950				--dev->udc_usage;
 951			}
 952			dev->state = STATE_DEV_CONNECTED;
 953
 954			/* assume that was SET_CONFIGURATION */
 955			if (dev->current_config) {
 956				unsigned power;
 957
 958				if (gadget_is_dualspeed(dev->gadget)
 959						&& (dev->gadget->speed
 960							== USB_SPEED_HIGH))
 961					power = dev->hs_config->bMaxPower;
 962				else
 963					power = dev->config->bMaxPower;
 964				usb_gadget_vbus_draw(dev->gadget, 2 * power);
 965			}
 966
 967		} else {			/* collect OUT data */
 968			if ((fd->f_flags & O_NONBLOCK) != 0
 969					&& !dev->setup_out_ready) {
 970				retval = -EAGAIN;
 971				goto done;
 972			}
 973			spin_unlock_irq (&dev->lock);
 974			retval = wait_event_interruptible (dev->wait,
 975					dev->setup_out_ready != 0);
 976
 977			/* FIXME state could change from under us */
 978			spin_lock_irq (&dev->lock);
 979			if (retval)
 980				goto done;
 981
 982			if (dev->state != STATE_DEV_SETUP) {
 983				retval = -ECANCELED;
 984				goto done;
 985			}
 986			dev->state = STATE_DEV_CONNECTED;
 987
 988			if (dev->setup_out_error)
 989				retval = -EIO;
 990			else {
 991				len = min (len, (size_t)dev->req->actual);
 992				++dev->udc_usage;
 993				spin_unlock_irq(&dev->lock);
 994				if (copy_to_user (buf, dev->req->buf, len))
 995					retval = -EFAULT;
 996				else
 997					retval = len;
 998				spin_lock_irq(&dev->lock);
 999				--dev->udc_usage;
1000				clean_req (dev->gadget->ep0, dev->req);
1001				/* NOTE userspace can't yet choose to stall */
1002			}
1003		}
1004		goto done;
1005	}
1006
1007	/* else normal: return event data */
1008	if (len < sizeof dev->event [0]) {
1009		retval = -EINVAL;
1010		goto done;
1011	}
1012	len -= len % sizeof (struct usb_gadgetfs_event);
1013	dev->usermode_setup = 1;
1014
1015scan:
1016	/* return queued events right away */
1017	if (dev->ev_next != 0) {
1018		unsigned		i, n;
1019
1020		n = len / sizeof (struct usb_gadgetfs_event);
1021		if (dev->ev_next < n)
1022			n = dev->ev_next;
1023
1024		/* ep0 i/o has special semantics during STATE_DEV_SETUP */
1025		for (i = 0; i < n; i++) {
1026			if (dev->event [i].type == GADGETFS_SETUP) {
1027				dev->state = STATE_DEV_SETUP;
1028				n = i + 1;
1029				break;
1030			}
1031		}
1032		spin_unlock_irq (&dev->lock);
1033		len = n * sizeof (struct usb_gadgetfs_event);
1034		if (copy_to_user (buf, &dev->event, len))
1035			retval = -EFAULT;
1036		else
1037			retval = len;
1038		if (len > 0) {
1039			/* NOTE this doesn't guard against broken drivers;
1040			 * concurrent ep0 readers may lose events.
1041			 */
1042			spin_lock_irq (&dev->lock);
1043			if (dev->ev_next > n) {
1044				memmove(&dev->event[0], &dev->event[n],
1045					sizeof (struct usb_gadgetfs_event)
1046						* (dev->ev_next - n));
1047			}
1048			dev->ev_next -= n;
1049			spin_unlock_irq (&dev->lock);
1050		}
1051		return retval;
1052	}
1053	if (fd->f_flags & O_NONBLOCK) {
1054		retval = -EAGAIN;
1055		goto done;
1056	}
1057
1058	switch (state) {
1059	default:
1060		DBG (dev, "fail %s, state %d\n", __func__, state);
1061		retval = -ESRCH;
1062		break;
1063	case STATE_DEV_UNCONNECTED:
1064	case STATE_DEV_CONNECTED:
1065		spin_unlock_irq (&dev->lock);
1066		DBG (dev, "%s wait\n", __func__);
1067
1068		/* wait for events */
1069		retval = wait_event_interruptible (dev->wait,
1070				dev->ev_next != 0);
1071		if (retval < 0)
1072			return retval;
1073		spin_lock_irq (&dev->lock);
1074		goto scan;
1075	}
1076
1077done:
1078	spin_unlock_irq (&dev->lock);
1079	return retval;
1080}
1081
1082static struct usb_gadgetfs_event *
1083next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1084{
1085	struct usb_gadgetfs_event	*event;
1086	unsigned			i;
1087
1088	switch (type) {
1089	/* these events purge the queue */
1090	case GADGETFS_DISCONNECT:
1091		if (dev->state == STATE_DEV_SETUP)
1092			dev->setup_abort = 1;
1093		fallthrough;
1094	case GADGETFS_CONNECT:
1095		dev->ev_next = 0;
1096		break;
1097	case GADGETFS_SETUP:		/* previous request timed out */
1098	case GADGETFS_SUSPEND:		/* same effect */
1099		/* these events can't be repeated */
1100		for (i = 0; i != dev->ev_next; i++) {
1101			if (dev->event [i].type != type)
1102				continue;
1103			DBG(dev, "discard old event[%d] %d\n", i, type);
1104			dev->ev_next--;
1105			if (i == dev->ev_next)
1106				break;
1107			/* indices start at zero, for simplicity */
1108			memmove (&dev->event [i], &dev->event [i + 1],
1109				sizeof (struct usb_gadgetfs_event)
1110					* (dev->ev_next - i));
1111		}
1112		break;
1113	default:
1114		BUG ();
1115	}
1116	VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1117	event = &dev->event [dev->ev_next++];
1118	BUG_ON (dev->ev_next > N_EVENT);
1119	memset (event, 0, sizeof *event);
1120	event->type = type;
1121	return event;
1122}
1123
1124static ssize_t
1125ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1126{
1127	struct dev_data		*dev = fd->private_data;
1128	ssize_t			retval = -ESRCH;
1129
1130	/* report fd mode change before acting on it */
1131	if (dev->setup_abort) {
1132		dev->setup_abort = 0;
1133		retval = -EIDRM;
1134
1135	/* data and/or status stage for control request */
1136	} else if (dev->state == STATE_DEV_SETUP) {
1137
1138		len = min_t(size_t, len, dev->setup_wLength);
1139		if (dev->setup_in) {
1140			retval = setup_req (dev->gadget->ep0, dev->req, len);
1141			if (retval == 0) {
1142				dev->state = STATE_DEV_CONNECTED;
1143				++dev->udc_usage;
1144				spin_unlock_irq (&dev->lock);
1145				if (copy_from_user (dev->req->buf, buf, len))
1146					retval = -EFAULT;
1147				else {
1148					if (len < dev->setup_wLength)
1149						dev->req->zero = 1;
1150					retval = usb_ep_queue (
1151						dev->gadget->ep0, dev->req,
1152						GFP_KERNEL);
1153				}
1154				spin_lock_irq(&dev->lock);
1155				--dev->udc_usage;
1156				if (retval < 0) {
1157					clean_req (dev->gadget->ep0, dev->req);
1158				} else
1159					retval = len;
1160
1161				return retval;
1162			}
1163
1164		/* can stall some OUT transfers */
1165		} else if (dev->setup_can_stall) {
1166			VDEBUG(dev, "ep0out stall\n");
1167			(void) usb_ep_set_halt (dev->gadget->ep0);
1168			retval = -EL2HLT;
1169			dev->state = STATE_DEV_CONNECTED;
1170		} else {
1171			DBG(dev, "bogus ep0out stall!\n");
1172		}
1173	} else
1174		DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1175
1176	return retval;
1177}
1178
1179static int
1180ep0_fasync (int f, struct file *fd, int on)
1181{
1182	struct dev_data		*dev = fd->private_data;
1183	// caller must F_SETOWN before signal delivery happens
1184	VDEBUG(dev, "%s %s\n", __func__, str_on_off(on));
1185	return fasync_helper (f, fd, on, &dev->fasync);
1186}
1187
1188static struct usb_gadget_driver gadgetfs_driver;
1189
1190static int
1191dev_release (struct inode *inode, struct file *fd)
1192{
1193	struct dev_data		*dev = fd->private_data;
1194
1195	/* closing ep0 === shutdown all */
1196
1197	if (dev->gadget_registered) {
1198		usb_gadget_unregister_driver (&gadgetfs_driver);
1199		dev->gadget_registered = false;
1200	}
1201
1202	/* at this point "good" hardware has disconnected the
1203	 * device from USB; the host won't see it any more.
1204	 * alternatively, all host requests will time out.
1205	 */
1206
1207	kfree (dev->buf);
1208	dev->buf = NULL;
1209
1210	/* other endpoints were all decoupled from this device */
1211	spin_lock_irq(&dev->lock);
1212	dev->state = STATE_DEV_DISABLED;
1213	spin_unlock_irq(&dev->lock);
1214
1215	put_dev (dev);
1216	return 0;
1217}
1218
1219static __poll_t
1220ep0_poll (struct file *fd, poll_table *wait)
1221{
1222	struct dev_data         *dev = fd->private_data;
1223	__poll_t                mask = 0;
1224
1225	if (dev->state <= STATE_DEV_OPENED)
1226		return DEFAULT_POLLMASK;
1227
1228	poll_wait(fd, &dev->wait, wait);
1229
1230	spin_lock_irq(&dev->lock);
1231
1232	/* report fd mode change before acting on it */
1233	if (dev->setup_abort) {
1234		dev->setup_abort = 0;
1235		mask = EPOLLHUP;
1236		goto out;
1237	}
1238
1239	if (dev->state == STATE_DEV_SETUP) {
1240		if (dev->setup_in || dev->setup_can_stall)
1241			mask = EPOLLOUT;
1242	} else {
1243		if (dev->ev_next != 0)
1244			mask = EPOLLIN;
1245	}
1246out:
1247	spin_unlock_irq(&dev->lock);
1248	return mask;
1249}
1250
1251static long gadget_dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1252{
1253	struct dev_data		*dev = fd->private_data;
1254	struct usb_gadget	*gadget = dev->gadget;
1255	long ret = -ENOTTY;
1256
1257	spin_lock_irq(&dev->lock);
1258	if (dev->state == STATE_DEV_OPENED ||
1259			dev->state == STATE_DEV_UNBOUND) {
1260		/* Not bound to a UDC */
1261	} else if (gadget->ops->ioctl) {
1262		++dev->udc_usage;
1263		spin_unlock_irq(&dev->lock);
1264
1265		ret = gadget->ops->ioctl (gadget, code, value);
1266
1267		spin_lock_irq(&dev->lock);
1268		--dev->udc_usage;
1269	}
1270	spin_unlock_irq(&dev->lock);
1271
1272	return ret;
1273}
1274
1275/*----------------------------------------------------------------------*/
1276
1277/* The in-kernel gadget driver handles most ep0 issues, in particular
1278 * enumerating the single configuration (as provided from user space).
1279 *
1280 * Unrecognized ep0 requests may be handled in user space.
1281 */
1282
1283static void make_qualifier (struct dev_data *dev)
1284{
1285	struct usb_qualifier_descriptor		qual;
1286	struct usb_device_descriptor		*desc;
1287
1288	qual.bLength = sizeof qual;
1289	qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1290	qual.bcdUSB = cpu_to_le16 (0x0200);
1291
1292	desc = dev->dev;
1293	qual.bDeviceClass = desc->bDeviceClass;
1294	qual.bDeviceSubClass = desc->bDeviceSubClass;
1295	qual.bDeviceProtocol = desc->bDeviceProtocol;
1296
1297	/* assumes ep0 uses the same value for both speeds ... */
1298	qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1299
1300	qual.bNumConfigurations = 1;
1301	qual.bRESERVED = 0;
1302
1303	memcpy (dev->rbuf, &qual, sizeof qual);
1304}
1305
1306static int
1307config_buf (struct dev_data *dev, u8 type, unsigned index)
1308{
1309	int		len;
1310	int		hs = 0;
1311
1312	/* only one configuration */
1313	if (index > 0)
1314		return -EINVAL;
1315
1316	if (gadget_is_dualspeed(dev->gadget)) {
1317		hs = (dev->gadget->speed == USB_SPEED_HIGH);
1318		if (type == USB_DT_OTHER_SPEED_CONFIG)
1319			hs = !hs;
1320	}
1321	if (hs) {
1322		dev->req->buf = dev->hs_config;
1323		len = le16_to_cpu(dev->hs_config->wTotalLength);
1324	} else {
1325		dev->req->buf = dev->config;
1326		len = le16_to_cpu(dev->config->wTotalLength);
1327	}
1328	((u8 *)dev->req->buf) [1] = type;
1329	return len;
1330}
1331
1332static int
1333gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1334{
1335	struct dev_data			*dev = get_gadget_data (gadget);
1336	struct usb_request		*req = dev->req;
1337	int				value = -EOPNOTSUPP;
1338	struct usb_gadgetfs_event	*event;
1339	u16				w_value = le16_to_cpu(ctrl->wValue);
1340	u16				w_length = le16_to_cpu(ctrl->wLength);
1341
1342	if (w_length > RBUF_SIZE) {
1343		if (ctrl->bRequestType & USB_DIR_IN) {
1344			/* Cast away the const, we are going to overwrite on purpose. */
1345			__le16 *temp = (__le16 *)&ctrl->wLength;
1346
1347			*temp = cpu_to_le16(RBUF_SIZE);
1348			w_length = RBUF_SIZE;
1349		} else {
1350			return value;
1351		}
1352	}
1353
1354	spin_lock (&dev->lock);
1355	dev->setup_abort = 0;
1356	if (dev->state == STATE_DEV_UNCONNECTED) {
1357		if (gadget_is_dualspeed(gadget)
1358				&& gadget->speed == USB_SPEED_HIGH
1359				&& dev->hs_config == NULL) {
1360			spin_unlock(&dev->lock);
1361			ERROR (dev, "no high speed config??\n");
1362			return -EINVAL;
1363		}
1364
1365		dev->state = STATE_DEV_CONNECTED;
1366
1367		INFO (dev, "connected\n");
1368		event = next_event (dev, GADGETFS_CONNECT);
1369		event->u.speed = gadget->speed;
1370		ep0_readable (dev);
1371
1372	/* host may have given up waiting for response.  we can miss control
1373	 * requests handled lower down (device/endpoint status and features);
1374	 * then ep0_{read,write} will report the wrong status. controller
1375	 * driver will have aborted pending i/o.
1376	 */
1377	} else if (dev->state == STATE_DEV_SETUP)
1378		dev->setup_abort = 1;
1379
1380	req->buf = dev->rbuf;
1381	req->context = NULL;
1382	switch (ctrl->bRequest) {
1383
1384	case USB_REQ_GET_DESCRIPTOR:
1385		if (ctrl->bRequestType != USB_DIR_IN)
1386			goto unrecognized;
1387		switch (w_value >> 8) {
1388
1389		case USB_DT_DEVICE:
1390			value = min (w_length, (u16) sizeof *dev->dev);
1391			dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1392			req->buf = dev->dev;
1393			break;
1394		case USB_DT_DEVICE_QUALIFIER:
1395			if (!dev->hs_config)
1396				break;
1397			value = min (w_length, (u16)
1398				sizeof (struct usb_qualifier_descriptor));
1399			make_qualifier (dev);
1400			break;
1401		case USB_DT_OTHER_SPEED_CONFIG:
1402		case USB_DT_CONFIG:
1403			value = config_buf (dev,
1404					w_value >> 8,
1405					w_value & 0xff);
1406			if (value >= 0)
1407				value = min (w_length, (u16) value);
1408			break;
1409		case USB_DT_STRING:
1410			goto unrecognized;
1411
1412		default:		// all others are errors
1413			break;
1414		}
1415		break;
1416
1417	/* currently one config, two speeds */
1418	case USB_REQ_SET_CONFIGURATION:
1419		if (ctrl->bRequestType != 0)
1420			goto unrecognized;
1421		if (0 == (u8) w_value) {
1422			value = 0;
1423			dev->current_config = 0;
1424			usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1425			// user mode expected to disable endpoints
1426		} else {
1427			u8	config, power;
1428
1429			if (gadget_is_dualspeed(gadget)
1430					&& gadget->speed == USB_SPEED_HIGH) {
1431				config = dev->hs_config->bConfigurationValue;
1432				power = dev->hs_config->bMaxPower;
1433			} else {
1434				config = dev->config->bConfigurationValue;
1435				power = dev->config->bMaxPower;
1436			}
1437
1438			if (config == (u8) w_value) {
1439				value = 0;
1440				dev->current_config = config;
1441				usb_gadget_vbus_draw(gadget, 2 * power);
1442			}
1443		}
1444
1445		/* report SET_CONFIGURATION like any other control request,
1446		 * except that usermode may not stall this.  the next
1447		 * request mustn't be allowed start until this finishes:
1448		 * endpoints and threads set up, etc.
1449		 *
1450		 * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1451		 * has bad/racey automagic that prevents synchronizing here.
1452		 * even kernel mode drivers often miss them.
1453		 */
1454		if (value == 0) {
1455			INFO (dev, "configuration #%d\n", dev->current_config);
1456			usb_gadget_set_state(gadget, USB_STATE_CONFIGURED);
1457			if (dev->usermode_setup) {
1458				dev->setup_can_stall = 0;
1459				goto delegate;
1460			}
1461		}
1462		break;
1463
1464#ifndef	CONFIG_USB_PXA25X
1465	/* PXA automagically handles this request too */
1466	case USB_REQ_GET_CONFIGURATION:
1467		if (ctrl->bRequestType != 0x80)
1468			goto unrecognized;
1469		*(u8 *)req->buf = dev->current_config;
1470		value = min (w_length, (u16) 1);
1471		break;
1472#endif
1473
1474	default:
1475unrecognized:
1476		VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1477			dev->usermode_setup ? "delegate" : "fail",
1478			ctrl->bRequestType, ctrl->bRequest,
1479			w_value, le16_to_cpu(ctrl->wIndex), w_length);
1480
1481		/* if there's an ep0 reader, don't stall */
1482		if (dev->usermode_setup) {
1483			dev->setup_can_stall = 1;
1484delegate:
1485			dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1486						? 1 : 0;
1487			dev->setup_wLength = w_length;
1488			dev->setup_out_ready = 0;
1489			dev->setup_out_error = 0;
1490
1491			/* read DATA stage for OUT right away */
1492			if (unlikely (!dev->setup_in && w_length)) {
1493				value = setup_req (gadget->ep0, dev->req,
1494							w_length);
1495				if (value < 0)
1496					break;
1497
1498				++dev->udc_usage;
1499				spin_unlock (&dev->lock);
1500				value = usb_ep_queue (gadget->ep0, dev->req,
1501							GFP_KERNEL);
1502				spin_lock (&dev->lock);
1503				--dev->udc_usage;
1504				if (value < 0) {
1505					clean_req (gadget->ep0, dev->req);
1506					break;
1507				}
1508
1509				/* we can't currently stall these */
1510				dev->setup_can_stall = 0;
1511			}
1512
1513			/* state changes when reader collects event */
1514			event = next_event (dev, GADGETFS_SETUP);
1515			event->u.setup = *ctrl;
1516			ep0_readable (dev);
1517			spin_unlock (&dev->lock);
1518			/*
1519			 * Return USB_GADGET_DELAYED_STATUS as a workaround to
1520			 * stop some UDC drivers (e.g. dwc3) from automatically
1521			 * proceeding with the status stage for 0-length
1522			 * transfers.
1523			 * Should be removed once all UDC drivers are fixed to
1524			 * always delay the status stage until a response is
1525			 * queued to EP0.
1526			 */
1527			return w_length == 0 ? USB_GADGET_DELAYED_STATUS : 0;
1528		}
1529	}
1530
1531	/* proceed with data transfer and status phases? */
1532	if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1533		req->length = value;
1534		req->zero = value < w_length;
1535
1536		++dev->udc_usage;
1537		spin_unlock (&dev->lock);
1538		value = usb_ep_queue (gadget->ep0, req, GFP_KERNEL);
1539		spin_lock(&dev->lock);
1540		--dev->udc_usage;
1541		spin_unlock(&dev->lock);
1542		if (value < 0) {
1543			DBG (dev, "ep_queue --> %d\n", value);
1544			req->status = 0;
1545		}
1546		return value;
1547	}
1548
1549	/* device stalls when value < 0 */
1550	spin_unlock (&dev->lock);
1551	return value;
1552}
1553
1554static void destroy_ep_files (struct dev_data *dev)
1555{
1556	DBG (dev, "%s %d\n", __func__, dev->state);
1557
1558	/* dev->state must prevent interference */
1559	spin_lock_irq (&dev->lock);
1560	while (!list_empty(&dev->epfiles)) {
1561		struct ep_data	*ep;
1562
1563		/* break link to FS */
1564		ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1565		list_del_init (&ep->epfiles);
1566		spin_unlock_irq (&dev->lock);
1567
1568		/* break link to controller */
1569		mutex_lock(&ep->lock);
1570		if (ep->state == STATE_EP_ENABLED)
1571			(void) usb_ep_disable (ep->ep);
1572		ep->state = STATE_EP_UNBOUND;
1573		usb_ep_free_request (ep->ep, ep->req);
1574		ep->ep = NULL;
1575		mutex_unlock(&ep->lock);
1576
1577		wake_up (&ep->wait);
1578
1579		/* break link to dcache */
1580		simple_remove_by_name(dev->sb->s_root, ep->name, NULL);
1581
1582		put_ep (ep);
1583
1584		spin_lock_irq (&dev->lock);
1585	}
1586	spin_unlock_irq (&dev->lock);
1587}
1588
1589
1590static int gadgetfs_create_file (struct super_block *sb, char const *name,
1591		void *data, const struct file_operations *fops);
1592
1593static int activate_ep_files (struct dev_data *dev)
1594{
1595	struct usb_ep	*ep;
1596	struct ep_data	*data;
1597	int err;
1598
1599	gadget_for_each_ep (ep, dev->gadget) {
1600
1601		data = kzalloc(sizeof(*data), GFP_KERNEL);
1602		if (!data)
1603			goto enomem0;
1604		data->state = STATE_EP_DISABLED;
1605		mutex_init(&data->lock);
1606		init_waitqueue_head (&data->wait);
1607
1608		strscpy(data->name, ep->name);
1609		refcount_set (&data->count, 1);
1610		data->dev = dev;
1611		get_dev (dev);
1612
1613		data->ep = ep;
1614		ep->driver_data = data;
1615
1616		data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1617		if (!data->req)
1618			goto enomem1;
1619
1620		err = gadgetfs_create_file (dev->sb, data->name,
1621				data, &ep_io_operations);
1622		if (err)
1623			goto enomem2;
1624		list_add_tail (&data->epfiles, &dev->epfiles);
1625	}
1626	return 0;
1627
1628enomem2:
1629	usb_ep_free_request (ep, data->req);
1630enomem1:
1631	put_dev (dev);
1632	kfree (data);
1633enomem0:
1634	DBG (dev, "%s enomem\n", __func__);
1635	destroy_ep_files (dev);
1636	return -ENOMEM;
1637}
1638
1639static void
1640gadgetfs_unbind (struct usb_gadget *gadget)
1641{
1642	struct dev_data		*dev = get_gadget_data (gadget);
1643
1644	DBG (dev, "%s\n", __func__);
1645
1646	spin_lock_irq (&dev->lock);
1647	dev->state = STATE_DEV_UNBOUND;
1648	while (dev->udc_usage > 0) {
1649		spin_unlock_irq(&dev->lock);
1650		usleep_range(1000, 2000);
1651		spin_lock_irq(&dev->lock);
1652	}
1653	spin_unlock_irq (&dev->lock);
1654
1655	destroy_ep_files (dev);
1656	gadget->ep0->driver_data = NULL;
1657	set_gadget_data (gadget, NULL);
1658
1659	/* we've already been disconnected ... no i/o is active */
1660	if (dev->req)
1661		usb_ep_free_request (gadget->ep0, dev->req);
1662	DBG (dev, "%s done\n", __func__);
1663	put_dev (dev);
1664}
1665
1666static struct dev_data		*the_device;
1667
1668static int gadgetfs_bind(struct usb_gadget *gadget,
1669		struct usb_gadget_driver *driver)
1670{
1671	struct dev_data		*dev = the_device;
1672
1673	if (!dev)
1674		return -ESRCH;
1675	if (0 != strcmp (CHIP, gadget->name)) {
1676		pr_err("%s expected %s controller not %s\n",
1677			shortname, CHIP, gadget->name);
1678		return -ENODEV;
1679	}
1680
1681	set_gadget_data (gadget, dev);
1682	dev->gadget = gadget;
1683	gadget->ep0->driver_data = dev;
1684
1685	/* preallocate control response and buffer */
1686	dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1687	if (!dev->req)
1688		goto enomem;
1689	dev->req->context = NULL;
1690	dev->req->complete = epio_complete;
1691
1692	if (activate_ep_files (dev) < 0)
1693		goto enomem;
1694
1695	INFO (dev, "bound to %s driver\n", gadget->name);
1696	spin_lock_irq(&dev->lock);
1697	dev->state = STATE_DEV_UNCONNECTED;
1698	spin_unlock_irq(&dev->lock);
1699	get_dev (dev);
1700	return 0;
1701
1702enomem:
1703	gadgetfs_unbind (gadget);
1704	return -ENOMEM;
1705}
1706
1707static void
1708gadgetfs_disconnect (struct usb_gadget *gadget)
1709{
1710	struct dev_data		*dev = get_gadget_data (gadget);
1711	unsigned long		flags;
1712
1713	spin_lock_irqsave (&dev->lock, flags);
1714	if (dev->state == STATE_DEV_UNCONNECTED)
1715		goto exit;
1716	dev->state = STATE_DEV_UNCONNECTED;
1717
1718	INFO (dev, "disconnected\n");
1719	next_event (dev, GADGETFS_DISCONNECT);
1720	ep0_readable (dev);
1721exit:
1722	spin_unlock_irqrestore (&dev->lock, flags);
1723}
1724
1725static void
1726gadgetfs_suspend (struct usb_gadget *gadget)
1727{
1728	struct dev_data		*dev = get_gadget_data (gadget);
1729	unsigned long		flags;
1730
1731	INFO (dev, "suspended from state %d\n", dev->state);
1732	spin_lock_irqsave(&dev->lock, flags);
1733	switch (dev->state) {
1734	case STATE_DEV_SETUP:		// VERY odd... host died??
1735	case STATE_DEV_CONNECTED:
1736	case STATE_DEV_UNCONNECTED:
1737		next_event (dev, GADGETFS_SUSPEND);
1738		ep0_readable (dev);
1739		fallthrough;
1740	default:
1741		break;
1742	}
1743	spin_unlock_irqrestore(&dev->lock, flags);
1744}
1745
1746static struct usb_gadget_driver gadgetfs_driver = {
1747	.function	= (char *) driver_desc,
1748	.bind		= gadgetfs_bind,
1749	.unbind		= gadgetfs_unbind,
1750	.setup		= gadgetfs_setup,
1751	.reset		= gadgetfs_disconnect,
1752	.disconnect	= gadgetfs_disconnect,
1753	.suspend	= gadgetfs_suspend,
1754
1755	.driver	= {
1756		.name		= shortname,
1757	},
1758};
1759
1760/*----------------------------------------------------------------------*/
1761/* DEVICE INITIALIZATION
1762 *
1763 *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1764 *     status = write (fd, descriptors, sizeof descriptors)
1765 *
1766 * That write establishes the device configuration, so the kernel can
1767 * bind to the controller ... guaranteeing it can handle enumeration
1768 * at all necessary speeds.  Descriptor order is:
1769 *
1770 * . message tag (u32, host order) ... for now, must be zero; it
1771 *	would change to support features like multi-config devices
1772 * . full/low speed config ... all wTotalLength bytes (with interface,
1773 *	class, altsetting, endpoint, and other descriptors)
1774 * . high speed config ... all descriptors, for high speed operation;
1775 *	this one's optional except for high-speed hardware
1776 * . device descriptor
1777 *
1778 * Endpoints are not yet enabled. Drivers must wait until device
1779 * configuration and interface altsetting changes create
1780 * the need to configure (or unconfigure) them.
1781 *
1782 * After initialization, the device stays active for as long as that
1783 * $CHIP file is open.  Events must then be read from that descriptor,
1784 * such as configuration notifications.
1785 */
1786
1787static int is_valid_config(struct usb_config_descriptor *config,
1788		unsigned int total)
1789{
1790	return config->bDescriptorType == USB_DT_CONFIG
1791		&& config->bLength == USB_DT_CONFIG_SIZE
1792		&& total >= USB_DT_CONFIG_SIZE
1793		&& config->bConfigurationValue != 0
1794		&& (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1795		&& (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1796	/* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1797	/* FIXME check lengths: walk to end */
1798}
1799
1800static ssize_t
1801dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1802{
1803	struct dev_data		*dev = fd->private_data;
1804	ssize_t			value, length = len;
1805	unsigned		total;
1806	u32			tag;
1807	char			*kbuf;
1808
1809	spin_lock_irq(&dev->lock);
1810	if (dev->state > STATE_DEV_OPENED) {
1811		value = ep0_write(fd, buf, len, ptr);
1812		spin_unlock_irq(&dev->lock);
1813		return value;
1814	}
1815	spin_unlock_irq(&dev->lock);
1816
1817	if ((len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4)) ||
1818	    (len > PAGE_SIZE * 4))
1819		return -EINVAL;
1820
1821	/* we might need to change message format someday */
1822	if (copy_from_user (&tag, buf, 4))
1823		return -EFAULT;
1824	if (tag != 0)
1825		return -EINVAL;
1826	buf += 4;
1827	length -= 4;
1828
1829	kbuf = memdup_user(buf, length);
1830	if (IS_ERR(kbuf))
1831		return PTR_ERR(kbuf);
1832
1833	spin_lock_irq (&dev->lock);
1834	value = -EINVAL;
1835	if (dev->buf) {
1836		spin_unlock_irq(&dev->lock);
1837		kfree(kbuf);
1838		return value;
1839	}
1840	dev->buf = kbuf;
1841
1842	/* full or low speed config */
1843	dev->config = (void *) kbuf;
1844	total = le16_to_cpu(dev->config->wTotalLength);
1845	if (!is_valid_config(dev->config, total) ||
1846			total > length - USB_DT_DEVICE_SIZE)
1847		goto fail;
1848	kbuf += total;
1849	length -= total;
1850
1851	/* optional high speed config */
1852	if (kbuf [1] == USB_DT_CONFIG) {
1853		dev->hs_config = (void *) kbuf;
1854		total = le16_to_cpu(dev->hs_config->wTotalLength);
1855		if (!is_valid_config(dev->hs_config, total) ||
1856				total > length - USB_DT_DEVICE_SIZE)
1857			goto fail;
1858		kbuf += total;
1859		length -= total;
1860	} else {
1861		dev->hs_config = NULL;
1862	}
1863
1864	/* could support multiple configs, using another encoding! */
1865
1866	/* device descriptor (tweaked for paranoia) */
1867	if (length != USB_DT_DEVICE_SIZE)
1868		goto fail;
1869	dev->dev = (void *)kbuf;
1870	if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1871			|| dev->dev->bDescriptorType != USB_DT_DEVICE
1872			|| dev->dev->bNumConfigurations != 1)
1873		goto fail;
1874	dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1875
1876	/* triggers gadgetfs_bind(); then we can enumerate. */
1877	spin_unlock_irq (&dev->lock);
1878	if (dev->hs_config)
1879		gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1880	else
1881		gadgetfs_driver.max_speed = USB_SPEED_FULL;
1882
1883	value = usb_gadget_register_driver(&gadgetfs_driver);
1884	if (value != 0) {
1885		spin_lock_irq(&dev->lock);
1886		goto fail;
1887	} else {
1888		/* at this point "good" hardware has for the first time
1889		 * let the USB the host see us.  alternatively, if users
1890		 * unplug/replug that will clear all the error state.
1891		 *
1892		 * note:  everything running before here was guaranteed
1893		 * to choke driver model style diagnostics.  from here
1894		 * on, they can work ... except in cleanup paths that
1895		 * kick in after the ep0 descriptor is closed.
1896		 */
1897		value = len;
1898		dev->gadget_registered = true;
1899	}
1900	return value;
1901
1902fail:
1903	dev->config = NULL;
1904	dev->hs_config = NULL;
1905	dev->dev = NULL;
1906	spin_unlock_irq (&dev->lock);
1907	pr_debug ("%s: %s fail %zd, %p\n", shortname, __func__, value, dev);
1908	kfree (dev->buf);
1909	dev->buf = NULL;
1910	return value;
1911}
1912
1913static int
1914gadget_dev_open (struct inode *inode, struct file *fd)
1915{
1916	struct dev_data		*dev = inode->i_private;
1917	int			value = -EBUSY;
1918
1919	spin_lock_irq(&dev->lock);
1920	if (dev->state == STATE_DEV_DISABLED) {
1921		dev->ev_next = 0;
1922		dev->state = STATE_DEV_OPENED;
1923		fd->private_data = dev;
1924		get_dev (dev);
1925		value = 0;
1926	}
1927	spin_unlock_irq(&dev->lock);
1928	return value;
1929}
1930
1931static const struct file_operations ep0_operations = {
1932
1933	.open =		gadget_dev_open,
1934	.read =		ep0_read,
1935	.write =	dev_config,
1936	.fasync =	ep0_fasync,
1937	.poll =		ep0_poll,
1938	.unlocked_ioctl = gadget_dev_ioctl,
1939	.release =	dev_release,
1940};
1941
1942/*----------------------------------------------------------------------*/
1943
1944/* FILESYSTEM AND SUPERBLOCK OPERATIONS
1945 *
1946 * Mounting the filesystem creates a controller file, used first for
1947 * device configuration then later for event monitoring.
1948 */
1949
1950
1951/* FIXME PAM etc could set this security policy without mount options
1952 * if epfiles inherited ownership and permissons from ep0 ...
1953 */
1954
1955static unsigned default_uid;
1956static unsigned default_gid;
1957static unsigned default_perm = S_IRUSR | S_IWUSR;
1958
1959module_param (default_uid, uint, 0644);
1960module_param (default_gid, uint, 0644);
1961module_param (default_perm, uint, 0644);
1962
1963
1964static struct inode *
1965gadgetfs_make_inode (struct super_block *sb,
1966		void *data, const struct file_operations *fops,
1967		int mode)
1968{
1969	struct inode *inode = new_inode (sb);
1970
1971	if (inode) {
1972		inode->i_ino = get_next_ino();
1973		inode->i_mode = mode;
1974		inode->i_uid = make_kuid(&init_user_ns, default_uid);
1975		inode->i_gid = make_kgid(&init_user_ns, default_gid);
1976		simple_inode_init_ts(inode);
1977		inode->i_private = data;
1978		inode->i_fop = fops;
1979	}
1980	return inode;
1981}
1982
1983/* creates in fs root directory, so non-renamable and non-linkable.
1984 * so inode and dentry are paired, until device reconfig.
1985 */
1986static int gadgetfs_create_file (struct super_block *sb, char const *name,
1987		void *data, const struct file_operations *fops)
1988{
1989	struct dentry	*dentry;
1990	struct inode	*inode;
1991
1992	inode = gadgetfs_make_inode (sb, data, fops,
1993			S_IFREG | (default_perm & S_IRWXUGO));
1994	if (!inode)
1995		return -ENOMEM;
1996
1997	dentry = simple_start_creating(sb->s_root, name);
1998	if (IS_ERR(dentry)) {
1999		iput(inode);
2000		return PTR_ERR(dentry);
2001	}
2002
2003	d_make_persistent(dentry, inode);
2004
2005	simple_done_creating(dentry);
2006	return 0;
2007}
2008
2009static const struct super_operations gadget_fs_operations = {
2010	.statfs =	simple_statfs,
2011	.drop_inode =	inode_just_drop,
2012};
2013
2014static int
2015gadgetfs_fill_super (struct super_block *sb, struct fs_context *fc)
2016{
2017	struct inode	*inode;
2018	struct dev_data	*dev;
2019	int		rc;
2020
2021	mutex_lock(&sb_mutex);
2022
2023	if (the_device) {
2024		rc = -ESRCH;
2025		goto Done;
2026	}
2027
2028	CHIP = usb_get_gadget_udc_name();
2029	if (!CHIP) {
2030		rc = -ENODEV;
2031		goto Done;
2032	}
2033
2034	/* superblock */
2035	sb->s_blocksize = PAGE_SIZE;
2036	sb->s_blocksize_bits = PAGE_SHIFT;
2037	sb->s_magic = GADGETFS_MAGIC;
2038	sb->s_op = &gadget_fs_operations;
2039	sb->s_time_gran = 1;
2040
2041	/* root inode */
2042	inode = gadgetfs_make_inode (sb,
2043			NULL, &simple_dir_operations,
2044			S_IFDIR | S_IRUGO | S_IXUGO);
2045	if (!inode)
2046		goto Enomem;
2047	inode->i_op = &simple_dir_inode_operations;
2048	if (!(sb->s_root = d_make_root (inode)))
2049		goto Enomem;
2050
2051	/* the ep0 file is named after the controller we expect;
2052	 * user mode code can use it for sanity checks, like we do.
2053	 */
2054	dev = dev_new ();
2055	if (!dev)
2056		goto Enomem;
2057
2058	dev->sb = sb;
2059	rc = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
2060	if (rc) {
2061		put_dev(dev);
2062		goto Enomem;
2063	}
2064
2065	/* other endpoint files are available after hardware setup,
2066	 * from binding to a controller.
2067	 */
2068	the_device = dev;
2069	rc = 0;
2070	goto Done;
2071
2072 Enomem:
2073	kfree(CHIP);
2074	CHIP = NULL;
2075	rc = -ENOMEM;
2076
2077 Done:
2078	mutex_unlock(&sb_mutex);
2079	return rc;
2080}
2081
2082/* "mount -t gadgetfs path /dev/gadget" ends up here */
2083static int gadgetfs_get_tree(struct fs_context *fc)
2084{
2085	return get_tree_single(fc, gadgetfs_fill_super);
2086}
2087
2088static const struct fs_context_operations gadgetfs_context_ops = {
2089	.get_tree	= gadgetfs_get_tree,
2090};
2091
2092static int gadgetfs_init_fs_context(struct fs_context *fc)
2093{
2094	fc->ops = &gadgetfs_context_ops;
2095	return 0;
2096}
2097
2098static void
2099gadgetfs_kill_sb (struct super_block *sb)
2100{
2101	mutex_lock(&sb_mutex);
2102	kill_anon_super (sb);
2103	if (the_device) {
2104		put_dev (the_device);
2105		the_device = NULL;
2106	}
2107	kfree(CHIP);
2108	CHIP = NULL;
2109	mutex_unlock(&sb_mutex);
2110}
2111
2112/*----------------------------------------------------------------------*/
2113
2114static struct file_system_type gadgetfs_type = {
2115	.owner		= THIS_MODULE,
2116	.name		= shortname,
2117	.init_fs_context = gadgetfs_init_fs_context,
2118	.kill_sb	= gadgetfs_kill_sb,
2119};
2120MODULE_ALIAS_FS("gadgetfs");
2121
2122/*----------------------------------------------------------------------*/
2123
2124static int __init gadgetfs_init (void)
2125{
2126	int status;
2127
2128	status = register_filesystem (&gadgetfs_type);
2129	if (status == 0)
2130		pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2131			shortname, driver_desc);
2132	return status;
2133}
2134module_init (gadgetfs_init);
2135
2136static void __exit gadgetfs_cleanup (void)
2137{
2138	pr_debug ("unregister %s\n", shortname);
2139	unregister_filesystem (&gadgetfs_type);
2140}
2141module_exit (gadgetfs_cleanup);
2142