xref: /openbmc/linux/drivers/usb/gadget/legacy/inode.c (revision 4f205687)
1 /*
2  * inode.c -- user mode filesystem api for usb gadget controllers
3  *
4  * Copyright (C) 2003-2004 David Brownell
5  * Copyright (C) 2003 Agilent Technologies
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  */
12 
13 
14 /* #define VERBOSE_DEBUG */
15 
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/fs.h>
19 #include <linux/pagemap.h>
20 #include <linux/uts.h>
21 #include <linux/wait.h>
22 #include <linux/compiler.h>
23 #include <asm/uaccess.h>
24 #include <linux/sched.h>
25 #include <linux/slab.h>
26 #include <linux/poll.h>
27 #include <linux/mmu_context.h>
28 #include <linux/aio.h>
29 #include <linux/uio.h>
30 
31 #include <linux/device.h>
32 #include <linux/moduleparam.h>
33 
34 #include <linux/usb/gadgetfs.h>
35 #include <linux/usb/gadget.h>
36 
37 
38 /*
39  * The gadgetfs API maps each endpoint to a file descriptor so that you
40  * can use standard synchronous read/write calls for I/O.  There's some
41  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
42  * drivers show how this works in practice.  You can also use AIO to
43  * eliminate I/O gaps between requests, to help when streaming data.
44  *
45  * Key parts that must be USB-specific are protocols defining how the
46  * read/write operations relate to the hardware state machines.  There
47  * are two types of files.  One type is for the device, implementing ep0.
48  * The other type is for each IN or OUT endpoint.  In both cases, the
49  * user mode driver must configure the hardware before using it.
50  *
51  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
52  *   (by writing configuration and device descriptors).  Afterwards it
53  *   may serve as a source of device events, used to handle all control
54  *   requests other than basic enumeration.
55  *
56  * - Then, after a SET_CONFIGURATION control request, ep_config() is
57  *   called when each /dev/gadget/ep* file is configured (by writing
58  *   endpoint descriptors).  Afterwards these files are used to write()
59  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
60  *   direction" request is issued (like reading an IN endpoint).
61  *
62  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
63  * not possible on all hardware.  For example, precise fault handling with
64  * respect to data left in endpoint fifos after aborted operations; or
65  * selective clearing of endpoint halts, to implement SET_INTERFACE.
66  */
67 
68 #define	DRIVER_DESC	"USB Gadget filesystem"
69 #define	DRIVER_VERSION	"24 Aug 2004"
70 
71 static const char driver_desc [] = DRIVER_DESC;
72 static const char shortname [] = "gadgetfs";
73 
74 MODULE_DESCRIPTION (DRIVER_DESC);
75 MODULE_AUTHOR ("David Brownell");
76 MODULE_LICENSE ("GPL");
77 
78 static int ep_open(struct inode *, struct file *);
79 
80 
81 /*----------------------------------------------------------------------*/
82 
83 #define GADGETFS_MAGIC		0xaee71ee7
84 
85 /* /dev/gadget/$CHIP represents ep0 and the whole device */
86 enum ep0_state {
87 	/* DISBLED is the initial state.
88 	 */
89 	STATE_DEV_DISABLED = 0,
90 
91 	/* Only one open() of /dev/gadget/$CHIP; only one file tracks
92 	 * ep0/device i/o modes and binding to the controller.  Driver
93 	 * must always write descriptors to initialize the device, then
94 	 * the device becomes UNCONNECTED until enumeration.
95 	 */
96 	STATE_DEV_OPENED,
97 
98 	/* From then on, ep0 fd is in either of two basic modes:
99 	 * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
100 	 * - SETUP: read/write will transfer control data and succeed;
101 	 *   or if "wrong direction", performs protocol stall
102 	 */
103 	STATE_DEV_UNCONNECTED,
104 	STATE_DEV_CONNECTED,
105 	STATE_DEV_SETUP,
106 
107 	/* UNBOUND means the driver closed ep0, so the device won't be
108 	 * accessible again (DEV_DISABLED) until all fds are closed.
109 	 */
110 	STATE_DEV_UNBOUND,
111 };
112 
113 /* enough for the whole queue: most events invalidate others */
114 #define	N_EVENT			5
115 
116 struct dev_data {
117 	spinlock_t			lock;
118 	atomic_t			count;
119 	enum ep0_state			state;		/* P: lock */
120 	struct usb_gadgetfs_event	event [N_EVENT];
121 	unsigned			ev_next;
122 	struct fasync_struct		*fasync;
123 	u8				current_config;
124 
125 	/* drivers reading ep0 MUST handle control requests (SETUP)
126 	 * reported that way; else the host will time out.
127 	 */
128 	unsigned			usermode_setup : 1,
129 					setup_in : 1,
130 					setup_can_stall : 1,
131 					setup_out_ready : 1,
132 					setup_out_error : 1,
133 					setup_abort : 1,
134 					gadget_registered : 1;
135 	unsigned			setup_wLength;
136 
137 	/* the rest is basically write-once */
138 	struct usb_config_descriptor	*config, *hs_config;
139 	struct usb_device_descriptor	*dev;
140 	struct usb_request		*req;
141 	struct usb_gadget		*gadget;
142 	struct list_head		epfiles;
143 	void				*buf;
144 	wait_queue_head_t		wait;
145 	struct super_block		*sb;
146 	struct dentry			*dentry;
147 
148 	/* except this scratch i/o buffer for ep0 */
149 	u8				rbuf [256];
150 };
151 
152 static inline void get_dev (struct dev_data *data)
153 {
154 	atomic_inc (&data->count);
155 }
156 
157 static void put_dev (struct dev_data *data)
158 {
159 	if (likely (!atomic_dec_and_test (&data->count)))
160 		return;
161 	/* needs no more cleanup */
162 	BUG_ON (waitqueue_active (&data->wait));
163 	kfree (data);
164 }
165 
166 static struct dev_data *dev_new (void)
167 {
168 	struct dev_data		*dev;
169 
170 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
171 	if (!dev)
172 		return NULL;
173 	dev->state = STATE_DEV_DISABLED;
174 	atomic_set (&dev->count, 1);
175 	spin_lock_init (&dev->lock);
176 	INIT_LIST_HEAD (&dev->epfiles);
177 	init_waitqueue_head (&dev->wait);
178 	return dev;
179 }
180 
181 /*----------------------------------------------------------------------*/
182 
183 /* other /dev/gadget/$ENDPOINT files represent endpoints */
184 enum ep_state {
185 	STATE_EP_DISABLED = 0,
186 	STATE_EP_READY,
187 	STATE_EP_ENABLED,
188 	STATE_EP_UNBOUND,
189 };
190 
191 struct ep_data {
192 	struct mutex			lock;
193 	enum ep_state			state;
194 	atomic_t			count;
195 	struct dev_data			*dev;
196 	/* must hold dev->lock before accessing ep or req */
197 	struct usb_ep			*ep;
198 	struct usb_request		*req;
199 	ssize_t				status;
200 	char				name [16];
201 	struct usb_endpoint_descriptor	desc, hs_desc;
202 	struct list_head		epfiles;
203 	wait_queue_head_t		wait;
204 	struct dentry			*dentry;
205 };
206 
207 static inline void get_ep (struct ep_data *data)
208 {
209 	atomic_inc (&data->count);
210 }
211 
212 static void put_ep (struct ep_data *data)
213 {
214 	if (likely (!atomic_dec_and_test (&data->count)))
215 		return;
216 	put_dev (data->dev);
217 	/* needs no more cleanup */
218 	BUG_ON (!list_empty (&data->epfiles));
219 	BUG_ON (waitqueue_active (&data->wait));
220 	kfree (data);
221 }
222 
223 /*----------------------------------------------------------------------*/
224 
225 /* most "how to use the hardware" policy choices are in userspace:
226  * mapping endpoint roles (which the driver needs) to the capabilities
227  * which the usb controller has.  most of those capabilities are exposed
228  * implicitly, starting with the driver name and then endpoint names.
229  */
230 
231 static const char *CHIP;
232 
233 /*----------------------------------------------------------------------*/
234 
235 /* NOTE:  don't use dev_printk calls before binding to the gadget
236  * at the end of ep0 configuration, or after unbind.
237  */
238 
239 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
240 #define xprintk(d,level,fmt,args...) \
241 	printk(level "%s: " fmt , shortname , ## args)
242 
243 #ifdef DEBUG
244 #define DBG(dev,fmt,args...) \
245 	xprintk(dev , KERN_DEBUG , fmt , ## args)
246 #else
247 #define DBG(dev,fmt,args...) \
248 	do { } while (0)
249 #endif /* DEBUG */
250 
251 #ifdef VERBOSE_DEBUG
252 #define VDEBUG	DBG
253 #else
254 #define VDEBUG(dev,fmt,args...) \
255 	do { } while (0)
256 #endif /* DEBUG */
257 
258 #define ERROR(dev,fmt,args...) \
259 	xprintk(dev , KERN_ERR , fmt , ## args)
260 #define INFO(dev,fmt,args...) \
261 	xprintk(dev , KERN_INFO , fmt , ## args)
262 
263 
264 /*----------------------------------------------------------------------*/
265 
266 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
267  *
268  * After opening, configure non-control endpoints.  Then use normal
269  * stream read() and write() requests; and maybe ioctl() to get more
270  * precise FIFO status when recovering from cancellation.
271  */
272 
273 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
274 {
275 	struct ep_data	*epdata = ep->driver_data;
276 
277 	if (!req->context)
278 		return;
279 	if (req->status)
280 		epdata->status = req->status;
281 	else
282 		epdata->status = req->actual;
283 	complete ((struct completion *)req->context);
284 }
285 
286 /* tasklock endpoint, returning when it's connected.
287  * still need dev->lock to use epdata->ep.
288  */
289 static int
290 get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write)
291 {
292 	int	val;
293 
294 	if (f_flags & O_NONBLOCK) {
295 		if (!mutex_trylock(&epdata->lock))
296 			goto nonblock;
297 		if (epdata->state != STATE_EP_ENABLED &&
298 		    (!is_write || epdata->state != STATE_EP_READY)) {
299 			mutex_unlock(&epdata->lock);
300 nonblock:
301 			val = -EAGAIN;
302 		} else
303 			val = 0;
304 		return val;
305 	}
306 
307 	val = mutex_lock_interruptible(&epdata->lock);
308 	if (val < 0)
309 		return val;
310 
311 	switch (epdata->state) {
312 	case STATE_EP_ENABLED:
313 		return 0;
314 	case STATE_EP_READY:			/* not configured yet */
315 		if (is_write)
316 			return 0;
317 		// FALLTHRU
318 	case STATE_EP_UNBOUND:			/* clean disconnect */
319 		break;
320 	// case STATE_EP_DISABLED:		/* "can't happen" */
321 	default:				/* error! */
322 		pr_debug ("%s: ep %p not available, state %d\n",
323 				shortname, epdata, epdata->state);
324 	}
325 	mutex_unlock(&epdata->lock);
326 	return -ENODEV;
327 }
328 
329 static ssize_t
330 ep_io (struct ep_data *epdata, void *buf, unsigned len)
331 {
332 	DECLARE_COMPLETION_ONSTACK (done);
333 	int value;
334 
335 	spin_lock_irq (&epdata->dev->lock);
336 	if (likely (epdata->ep != NULL)) {
337 		struct usb_request	*req = epdata->req;
338 
339 		req->context = &done;
340 		req->complete = epio_complete;
341 		req->buf = buf;
342 		req->length = len;
343 		value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
344 	} else
345 		value = -ENODEV;
346 	spin_unlock_irq (&epdata->dev->lock);
347 
348 	if (likely (value == 0)) {
349 		value = wait_event_interruptible (done.wait, done.done);
350 		if (value != 0) {
351 			spin_lock_irq (&epdata->dev->lock);
352 			if (likely (epdata->ep != NULL)) {
353 				DBG (epdata->dev, "%s i/o interrupted\n",
354 						epdata->name);
355 				usb_ep_dequeue (epdata->ep, epdata->req);
356 				spin_unlock_irq (&epdata->dev->lock);
357 
358 				wait_event (done.wait, done.done);
359 				if (epdata->status == -ECONNRESET)
360 					epdata->status = -EINTR;
361 			} else {
362 				spin_unlock_irq (&epdata->dev->lock);
363 
364 				DBG (epdata->dev, "endpoint gone\n");
365 				epdata->status = -ENODEV;
366 			}
367 		}
368 		return epdata->status;
369 	}
370 	return value;
371 }
372 
373 static int
374 ep_release (struct inode *inode, struct file *fd)
375 {
376 	struct ep_data		*data = fd->private_data;
377 	int value;
378 
379 	value = mutex_lock_interruptible(&data->lock);
380 	if (value < 0)
381 		return value;
382 
383 	/* clean up if this can be reopened */
384 	if (data->state != STATE_EP_UNBOUND) {
385 		data->state = STATE_EP_DISABLED;
386 		data->desc.bDescriptorType = 0;
387 		data->hs_desc.bDescriptorType = 0;
388 		usb_ep_disable(data->ep);
389 	}
390 	mutex_unlock(&data->lock);
391 	put_ep (data);
392 	return 0;
393 }
394 
395 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
396 {
397 	struct ep_data		*data = fd->private_data;
398 	int			status;
399 
400 	if ((status = get_ready_ep (fd->f_flags, data, false)) < 0)
401 		return status;
402 
403 	spin_lock_irq (&data->dev->lock);
404 	if (likely (data->ep != NULL)) {
405 		switch (code) {
406 		case GADGETFS_FIFO_STATUS:
407 			status = usb_ep_fifo_status (data->ep);
408 			break;
409 		case GADGETFS_FIFO_FLUSH:
410 			usb_ep_fifo_flush (data->ep);
411 			break;
412 		case GADGETFS_CLEAR_HALT:
413 			status = usb_ep_clear_halt (data->ep);
414 			break;
415 		default:
416 			status = -ENOTTY;
417 		}
418 	} else
419 		status = -ENODEV;
420 	spin_unlock_irq (&data->dev->lock);
421 	mutex_unlock(&data->lock);
422 	return status;
423 }
424 
425 /*----------------------------------------------------------------------*/
426 
427 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
428 
429 struct kiocb_priv {
430 	struct usb_request	*req;
431 	struct ep_data		*epdata;
432 	struct kiocb		*iocb;
433 	struct mm_struct	*mm;
434 	struct work_struct	work;
435 	void			*buf;
436 	struct iov_iter		to;
437 	const void		*to_free;
438 	unsigned		actual;
439 };
440 
441 static int ep_aio_cancel(struct kiocb *iocb)
442 {
443 	struct kiocb_priv	*priv = iocb->private;
444 	struct ep_data		*epdata;
445 	int			value;
446 
447 	local_irq_disable();
448 	epdata = priv->epdata;
449 	// spin_lock(&epdata->dev->lock);
450 	if (likely(epdata && epdata->ep && priv->req))
451 		value = usb_ep_dequeue (epdata->ep, priv->req);
452 	else
453 		value = -EINVAL;
454 	// spin_unlock(&epdata->dev->lock);
455 	local_irq_enable();
456 
457 	return value;
458 }
459 
460 static void ep_user_copy_worker(struct work_struct *work)
461 {
462 	struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
463 	struct mm_struct *mm = priv->mm;
464 	struct kiocb *iocb = priv->iocb;
465 	size_t ret;
466 
467 	use_mm(mm);
468 	ret = copy_to_iter(priv->buf, priv->actual, &priv->to);
469 	unuse_mm(mm);
470 	if (!ret)
471 		ret = -EFAULT;
472 
473 	/* completing the iocb can drop the ctx and mm, don't touch mm after */
474 	iocb->ki_complete(iocb, ret, ret);
475 
476 	kfree(priv->buf);
477 	kfree(priv->to_free);
478 	kfree(priv);
479 }
480 
481 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
482 {
483 	struct kiocb		*iocb = req->context;
484 	struct kiocb_priv	*priv = iocb->private;
485 	struct ep_data		*epdata = priv->epdata;
486 
487 	/* lock against disconnect (and ideally, cancel) */
488 	spin_lock(&epdata->dev->lock);
489 	priv->req = NULL;
490 	priv->epdata = NULL;
491 
492 	/* if this was a write or a read returning no data then we
493 	 * don't need to copy anything to userspace, so we can
494 	 * complete the aio request immediately.
495 	 */
496 	if (priv->to_free == NULL || unlikely(req->actual == 0)) {
497 		kfree(req->buf);
498 		kfree(priv->to_free);
499 		kfree(priv);
500 		iocb->private = NULL;
501 		/* aio_complete() reports bytes-transferred _and_ faults */
502 
503 		iocb->ki_complete(iocb, req->actual ? req->actual : req->status,
504 				req->status);
505 	} else {
506 		/* ep_copy_to_user() won't report both; we hide some faults */
507 		if (unlikely(0 != req->status))
508 			DBG(epdata->dev, "%s fault %d len %d\n",
509 				ep->name, req->status, req->actual);
510 
511 		priv->buf = req->buf;
512 		priv->actual = req->actual;
513 		INIT_WORK(&priv->work, ep_user_copy_worker);
514 		schedule_work(&priv->work);
515 	}
516 	spin_unlock(&epdata->dev->lock);
517 
518 	usb_ep_free_request(ep, req);
519 	put_ep(epdata);
520 }
521 
522 static ssize_t ep_aio(struct kiocb *iocb,
523 		      struct kiocb_priv *priv,
524 		      struct ep_data *epdata,
525 		      char *buf,
526 		      size_t len)
527 {
528 	struct usb_request *req;
529 	ssize_t value;
530 
531 	iocb->private = priv;
532 	priv->iocb = iocb;
533 
534 	kiocb_set_cancel_fn(iocb, ep_aio_cancel);
535 	get_ep(epdata);
536 	priv->epdata = epdata;
537 	priv->actual = 0;
538 	priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
539 
540 	/* each kiocb is coupled to one usb_request, but we can't
541 	 * allocate or submit those if the host disconnected.
542 	 */
543 	spin_lock_irq(&epdata->dev->lock);
544 	value = -ENODEV;
545 	if (unlikely(epdata->ep))
546 		goto fail;
547 
548 	req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
549 	value = -ENOMEM;
550 	if (unlikely(!req))
551 		goto fail;
552 
553 	priv->req = req;
554 	req->buf = buf;
555 	req->length = len;
556 	req->complete = ep_aio_complete;
557 	req->context = iocb;
558 	value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
559 	if (unlikely(0 != value)) {
560 		usb_ep_free_request(epdata->ep, req);
561 		goto fail;
562 	}
563 	spin_unlock_irq(&epdata->dev->lock);
564 	return -EIOCBQUEUED;
565 
566 fail:
567 	spin_unlock_irq(&epdata->dev->lock);
568 	kfree(priv->to_free);
569 	kfree(priv);
570 	put_ep(epdata);
571 	return value;
572 }
573 
574 static ssize_t
575 ep_read_iter(struct kiocb *iocb, struct iov_iter *to)
576 {
577 	struct file *file = iocb->ki_filp;
578 	struct ep_data *epdata = file->private_data;
579 	size_t len = iov_iter_count(to);
580 	ssize_t value;
581 	char *buf;
582 
583 	if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0)
584 		return value;
585 
586 	/* halt any endpoint by doing a "wrong direction" i/o call */
587 	if (usb_endpoint_dir_in(&epdata->desc)) {
588 		if (usb_endpoint_xfer_isoc(&epdata->desc) ||
589 		    !is_sync_kiocb(iocb)) {
590 			mutex_unlock(&epdata->lock);
591 			return -EINVAL;
592 		}
593 		DBG (epdata->dev, "%s halt\n", epdata->name);
594 		spin_lock_irq(&epdata->dev->lock);
595 		if (likely(epdata->ep != NULL))
596 			usb_ep_set_halt(epdata->ep);
597 		spin_unlock_irq(&epdata->dev->lock);
598 		mutex_unlock(&epdata->lock);
599 		return -EBADMSG;
600 	}
601 
602 	buf = kmalloc(len, GFP_KERNEL);
603 	if (unlikely(!buf)) {
604 		mutex_unlock(&epdata->lock);
605 		return -ENOMEM;
606 	}
607 	if (is_sync_kiocb(iocb)) {
608 		value = ep_io(epdata, buf, len);
609 		if (value >= 0 && copy_to_iter(buf, value, to))
610 			value = -EFAULT;
611 	} else {
612 		struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
613 		value = -ENOMEM;
614 		if (!priv)
615 			goto fail;
616 		priv->to_free = dup_iter(&priv->to, to, GFP_KERNEL);
617 		if (!priv->to_free) {
618 			kfree(priv);
619 			goto fail;
620 		}
621 		value = ep_aio(iocb, priv, epdata, buf, len);
622 		if (value == -EIOCBQUEUED)
623 			buf = NULL;
624 	}
625 fail:
626 	kfree(buf);
627 	mutex_unlock(&epdata->lock);
628 	return value;
629 }
630 
631 static ssize_t ep_config(struct ep_data *, const char *, size_t);
632 
633 static ssize_t
634 ep_write_iter(struct kiocb *iocb, struct iov_iter *from)
635 {
636 	struct file *file = iocb->ki_filp;
637 	struct ep_data *epdata = file->private_data;
638 	size_t len = iov_iter_count(from);
639 	bool configured;
640 	ssize_t value;
641 	char *buf;
642 
643 	if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0)
644 		return value;
645 
646 	configured = epdata->state == STATE_EP_ENABLED;
647 
648 	/* halt any endpoint by doing a "wrong direction" i/o call */
649 	if (configured && !usb_endpoint_dir_in(&epdata->desc)) {
650 		if (usb_endpoint_xfer_isoc(&epdata->desc) ||
651 		    !is_sync_kiocb(iocb)) {
652 			mutex_unlock(&epdata->lock);
653 			return -EINVAL;
654 		}
655 		DBG (epdata->dev, "%s halt\n", epdata->name);
656 		spin_lock_irq(&epdata->dev->lock);
657 		if (likely(epdata->ep != NULL))
658 			usb_ep_set_halt(epdata->ep);
659 		spin_unlock_irq(&epdata->dev->lock);
660 		mutex_unlock(&epdata->lock);
661 		return -EBADMSG;
662 	}
663 
664 	buf = kmalloc(len, GFP_KERNEL);
665 	if (unlikely(!buf)) {
666 		mutex_unlock(&epdata->lock);
667 		return -ENOMEM;
668 	}
669 
670 	if (unlikely(copy_from_iter(buf, len, from) != len)) {
671 		value = -EFAULT;
672 		goto out;
673 	}
674 
675 	if (unlikely(!configured)) {
676 		value = ep_config(epdata, buf, len);
677 	} else if (is_sync_kiocb(iocb)) {
678 		value = ep_io(epdata, buf, len);
679 	} else {
680 		struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
681 		value = -ENOMEM;
682 		if (priv) {
683 			value = ep_aio(iocb, priv, epdata, buf, len);
684 			if (value == -EIOCBQUEUED)
685 				buf = NULL;
686 		}
687 	}
688 out:
689 	kfree(buf);
690 	mutex_unlock(&epdata->lock);
691 	return value;
692 }
693 
694 /*----------------------------------------------------------------------*/
695 
696 /* used after endpoint configuration */
697 static const struct file_operations ep_io_operations = {
698 	.owner =	THIS_MODULE,
699 
700 	.open =		ep_open,
701 	.release =	ep_release,
702 	.llseek =	no_llseek,
703 	.unlocked_ioctl = ep_ioctl,
704 	.read_iter =	ep_read_iter,
705 	.write_iter =	ep_write_iter,
706 };
707 
708 /* ENDPOINT INITIALIZATION
709  *
710  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
711  *     status = write (fd, descriptors, sizeof descriptors)
712  *
713  * That write establishes the endpoint configuration, configuring
714  * the controller to process bulk, interrupt, or isochronous transfers
715  * at the right maxpacket size, and so on.
716  *
717  * The descriptors are message type 1, identified by a host order u32
718  * at the beginning of what's written.  Descriptor order is: full/low
719  * speed descriptor, then optional high speed descriptor.
720  */
721 static ssize_t
722 ep_config (struct ep_data *data, const char *buf, size_t len)
723 {
724 	struct usb_ep		*ep;
725 	u32			tag;
726 	int			value, length = len;
727 
728 	if (data->state != STATE_EP_READY) {
729 		value = -EL2HLT;
730 		goto fail;
731 	}
732 
733 	value = len;
734 	if (len < USB_DT_ENDPOINT_SIZE + 4)
735 		goto fail0;
736 
737 	/* we might need to change message format someday */
738 	memcpy(&tag, buf, 4);
739 	if (tag != 1) {
740 		DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
741 		goto fail0;
742 	}
743 	buf += 4;
744 	len -= 4;
745 
746 	/* NOTE:  audio endpoint extensions not accepted here;
747 	 * just don't include the extra bytes.
748 	 */
749 
750 	/* full/low speed descriptor, then high speed */
751 	memcpy(&data->desc, buf, USB_DT_ENDPOINT_SIZE);
752 	if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
753 			|| data->desc.bDescriptorType != USB_DT_ENDPOINT)
754 		goto fail0;
755 	if (len != USB_DT_ENDPOINT_SIZE) {
756 		if (len != 2 * USB_DT_ENDPOINT_SIZE)
757 			goto fail0;
758 		memcpy(&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
759 			USB_DT_ENDPOINT_SIZE);
760 		if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
761 				|| data->hs_desc.bDescriptorType
762 					!= USB_DT_ENDPOINT) {
763 			DBG(data->dev, "config %s, bad hs length or type\n",
764 					data->name);
765 			goto fail0;
766 		}
767 	}
768 
769 	spin_lock_irq (&data->dev->lock);
770 	if (data->dev->state == STATE_DEV_UNBOUND) {
771 		value = -ENOENT;
772 		goto gone;
773 	} else {
774 		ep = data->ep;
775 		if (ep == NULL) {
776 			value = -ENODEV;
777 			goto gone;
778 		}
779 	}
780 	switch (data->dev->gadget->speed) {
781 	case USB_SPEED_LOW:
782 	case USB_SPEED_FULL:
783 		ep->desc = &data->desc;
784 		break;
785 	case USB_SPEED_HIGH:
786 		/* fails if caller didn't provide that descriptor... */
787 		ep->desc = &data->hs_desc;
788 		break;
789 	default:
790 		DBG(data->dev, "unconnected, %s init abandoned\n",
791 				data->name);
792 		value = -EINVAL;
793 		goto gone;
794 	}
795 	value = usb_ep_enable(ep);
796 	if (value == 0) {
797 		data->state = STATE_EP_ENABLED;
798 		value = length;
799 	}
800 gone:
801 	spin_unlock_irq (&data->dev->lock);
802 	if (value < 0) {
803 fail:
804 		data->desc.bDescriptorType = 0;
805 		data->hs_desc.bDescriptorType = 0;
806 	}
807 	return value;
808 fail0:
809 	value = -EINVAL;
810 	goto fail;
811 }
812 
813 static int
814 ep_open (struct inode *inode, struct file *fd)
815 {
816 	struct ep_data		*data = inode->i_private;
817 	int			value = -EBUSY;
818 
819 	if (mutex_lock_interruptible(&data->lock) != 0)
820 		return -EINTR;
821 	spin_lock_irq (&data->dev->lock);
822 	if (data->dev->state == STATE_DEV_UNBOUND)
823 		value = -ENOENT;
824 	else if (data->state == STATE_EP_DISABLED) {
825 		value = 0;
826 		data->state = STATE_EP_READY;
827 		get_ep (data);
828 		fd->private_data = data;
829 		VDEBUG (data->dev, "%s ready\n", data->name);
830 	} else
831 		DBG (data->dev, "%s state %d\n",
832 			data->name, data->state);
833 	spin_unlock_irq (&data->dev->lock);
834 	mutex_unlock(&data->lock);
835 	return value;
836 }
837 
838 /*----------------------------------------------------------------------*/
839 
840 /* EP0 IMPLEMENTATION can be partly in userspace.
841  *
842  * Drivers that use this facility receive various events, including
843  * control requests the kernel doesn't handle.  Drivers that don't
844  * use this facility may be too simple-minded for real applications.
845  */
846 
847 static inline void ep0_readable (struct dev_data *dev)
848 {
849 	wake_up (&dev->wait);
850 	kill_fasync (&dev->fasync, SIGIO, POLL_IN);
851 }
852 
853 static void clean_req (struct usb_ep *ep, struct usb_request *req)
854 {
855 	struct dev_data		*dev = ep->driver_data;
856 
857 	if (req->buf != dev->rbuf) {
858 		kfree(req->buf);
859 		req->buf = dev->rbuf;
860 	}
861 	req->complete = epio_complete;
862 	dev->setup_out_ready = 0;
863 }
864 
865 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
866 {
867 	struct dev_data		*dev = ep->driver_data;
868 	unsigned long		flags;
869 	int			free = 1;
870 
871 	/* for control OUT, data must still get to userspace */
872 	spin_lock_irqsave(&dev->lock, flags);
873 	if (!dev->setup_in) {
874 		dev->setup_out_error = (req->status != 0);
875 		if (!dev->setup_out_error)
876 			free = 0;
877 		dev->setup_out_ready = 1;
878 		ep0_readable (dev);
879 	}
880 
881 	/* clean up as appropriate */
882 	if (free && req->buf != &dev->rbuf)
883 		clean_req (ep, req);
884 	req->complete = epio_complete;
885 	spin_unlock_irqrestore(&dev->lock, flags);
886 }
887 
888 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
889 {
890 	struct dev_data	*dev = ep->driver_data;
891 
892 	if (dev->setup_out_ready) {
893 		DBG (dev, "ep0 request busy!\n");
894 		return -EBUSY;
895 	}
896 	if (len > sizeof (dev->rbuf))
897 		req->buf = kmalloc(len, GFP_ATOMIC);
898 	if (req->buf == NULL) {
899 		req->buf = dev->rbuf;
900 		return -ENOMEM;
901 	}
902 	req->complete = ep0_complete;
903 	req->length = len;
904 	req->zero = 0;
905 	return 0;
906 }
907 
908 static ssize_t
909 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
910 {
911 	struct dev_data			*dev = fd->private_data;
912 	ssize_t				retval;
913 	enum ep0_state			state;
914 
915 	spin_lock_irq (&dev->lock);
916 	if (dev->state <= STATE_DEV_OPENED) {
917 		retval = -EINVAL;
918 		goto done;
919 	}
920 
921 	/* report fd mode change before acting on it */
922 	if (dev->setup_abort) {
923 		dev->setup_abort = 0;
924 		retval = -EIDRM;
925 		goto done;
926 	}
927 
928 	/* control DATA stage */
929 	if ((state = dev->state) == STATE_DEV_SETUP) {
930 
931 		if (dev->setup_in) {		/* stall IN */
932 			VDEBUG(dev, "ep0in stall\n");
933 			(void) usb_ep_set_halt (dev->gadget->ep0);
934 			retval = -EL2HLT;
935 			dev->state = STATE_DEV_CONNECTED;
936 
937 		} else if (len == 0) {		/* ack SET_CONFIGURATION etc */
938 			struct usb_ep		*ep = dev->gadget->ep0;
939 			struct usb_request	*req = dev->req;
940 
941 			if ((retval = setup_req (ep, req, 0)) == 0) {
942 				spin_unlock_irq (&dev->lock);
943 				retval = usb_ep_queue (ep, req, GFP_KERNEL);
944 				spin_lock_irq (&dev->lock);
945 			}
946 			dev->state = STATE_DEV_CONNECTED;
947 
948 			/* assume that was SET_CONFIGURATION */
949 			if (dev->current_config) {
950 				unsigned power;
951 
952 				if (gadget_is_dualspeed(dev->gadget)
953 						&& (dev->gadget->speed
954 							== USB_SPEED_HIGH))
955 					power = dev->hs_config->bMaxPower;
956 				else
957 					power = dev->config->bMaxPower;
958 				usb_gadget_vbus_draw(dev->gadget, 2 * power);
959 			}
960 
961 		} else {			/* collect OUT data */
962 			if ((fd->f_flags & O_NONBLOCK) != 0
963 					&& !dev->setup_out_ready) {
964 				retval = -EAGAIN;
965 				goto done;
966 			}
967 			spin_unlock_irq (&dev->lock);
968 			retval = wait_event_interruptible (dev->wait,
969 					dev->setup_out_ready != 0);
970 
971 			/* FIXME state could change from under us */
972 			spin_lock_irq (&dev->lock);
973 			if (retval)
974 				goto done;
975 
976 			if (dev->state != STATE_DEV_SETUP) {
977 				retval = -ECANCELED;
978 				goto done;
979 			}
980 			dev->state = STATE_DEV_CONNECTED;
981 
982 			if (dev->setup_out_error)
983 				retval = -EIO;
984 			else {
985 				len = min (len, (size_t)dev->req->actual);
986 // FIXME don't call this with the spinlock held ...
987 				if (copy_to_user (buf, dev->req->buf, len))
988 					retval = -EFAULT;
989 				else
990 					retval = len;
991 				clean_req (dev->gadget->ep0, dev->req);
992 				/* NOTE userspace can't yet choose to stall */
993 			}
994 		}
995 		goto done;
996 	}
997 
998 	/* else normal: return event data */
999 	if (len < sizeof dev->event [0]) {
1000 		retval = -EINVAL;
1001 		goto done;
1002 	}
1003 	len -= len % sizeof (struct usb_gadgetfs_event);
1004 	dev->usermode_setup = 1;
1005 
1006 scan:
1007 	/* return queued events right away */
1008 	if (dev->ev_next != 0) {
1009 		unsigned		i, n;
1010 
1011 		n = len / sizeof (struct usb_gadgetfs_event);
1012 		if (dev->ev_next < n)
1013 			n = dev->ev_next;
1014 
1015 		/* ep0 i/o has special semantics during STATE_DEV_SETUP */
1016 		for (i = 0; i < n; i++) {
1017 			if (dev->event [i].type == GADGETFS_SETUP) {
1018 				dev->state = STATE_DEV_SETUP;
1019 				n = i + 1;
1020 				break;
1021 			}
1022 		}
1023 		spin_unlock_irq (&dev->lock);
1024 		len = n * sizeof (struct usb_gadgetfs_event);
1025 		if (copy_to_user (buf, &dev->event, len))
1026 			retval = -EFAULT;
1027 		else
1028 			retval = len;
1029 		if (len > 0) {
1030 			/* NOTE this doesn't guard against broken drivers;
1031 			 * concurrent ep0 readers may lose events.
1032 			 */
1033 			spin_lock_irq (&dev->lock);
1034 			if (dev->ev_next > n) {
1035 				memmove(&dev->event[0], &dev->event[n],
1036 					sizeof (struct usb_gadgetfs_event)
1037 						* (dev->ev_next - n));
1038 			}
1039 			dev->ev_next -= n;
1040 			spin_unlock_irq (&dev->lock);
1041 		}
1042 		return retval;
1043 	}
1044 	if (fd->f_flags & O_NONBLOCK) {
1045 		retval = -EAGAIN;
1046 		goto done;
1047 	}
1048 
1049 	switch (state) {
1050 	default:
1051 		DBG (dev, "fail %s, state %d\n", __func__, state);
1052 		retval = -ESRCH;
1053 		break;
1054 	case STATE_DEV_UNCONNECTED:
1055 	case STATE_DEV_CONNECTED:
1056 		spin_unlock_irq (&dev->lock);
1057 		DBG (dev, "%s wait\n", __func__);
1058 
1059 		/* wait for events */
1060 		retval = wait_event_interruptible (dev->wait,
1061 				dev->ev_next != 0);
1062 		if (retval < 0)
1063 			return retval;
1064 		spin_lock_irq (&dev->lock);
1065 		goto scan;
1066 	}
1067 
1068 done:
1069 	spin_unlock_irq (&dev->lock);
1070 	return retval;
1071 }
1072 
1073 static struct usb_gadgetfs_event *
1074 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1075 {
1076 	struct usb_gadgetfs_event	*event;
1077 	unsigned			i;
1078 
1079 	switch (type) {
1080 	/* these events purge the queue */
1081 	case GADGETFS_DISCONNECT:
1082 		if (dev->state == STATE_DEV_SETUP)
1083 			dev->setup_abort = 1;
1084 		// FALL THROUGH
1085 	case GADGETFS_CONNECT:
1086 		dev->ev_next = 0;
1087 		break;
1088 	case GADGETFS_SETUP:		/* previous request timed out */
1089 	case GADGETFS_SUSPEND:		/* same effect */
1090 		/* these events can't be repeated */
1091 		for (i = 0; i != dev->ev_next; i++) {
1092 			if (dev->event [i].type != type)
1093 				continue;
1094 			DBG(dev, "discard old event[%d] %d\n", i, type);
1095 			dev->ev_next--;
1096 			if (i == dev->ev_next)
1097 				break;
1098 			/* indices start at zero, for simplicity */
1099 			memmove (&dev->event [i], &dev->event [i + 1],
1100 				sizeof (struct usb_gadgetfs_event)
1101 					* (dev->ev_next - i));
1102 		}
1103 		break;
1104 	default:
1105 		BUG ();
1106 	}
1107 	VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1108 	event = &dev->event [dev->ev_next++];
1109 	BUG_ON (dev->ev_next > N_EVENT);
1110 	memset (event, 0, sizeof *event);
1111 	event->type = type;
1112 	return event;
1113 }
1114 
1115 static ssize_t
1116 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1117 {
1118 	struct dev_data		*dev = fd->private_data;
1119 	ssize_t			retval = -ESRCH;
1120 
1121 	/* report fd mode change before acting on it */
1122 	if (dev->setup_abort) {
1123 		dev->setup_abort = 0;
1124 		retval = -EIDRM;
1125 
1126 	/* data and/or status stage for control request */
1127 	} else if (dev->state == STATE_DEV_SETUP) {
1128 
1129 		/* IN DATA+STATUS caller makes len <= wLength */
1130 		if (dev->setup_in) {
1131 			retval = setup_req (dev->gadget->ep0, dev->req, len);
1132 			if (retval == 0) {
1133 				dev->state = STATE_DEV_CONNECTED;
1134 				spin_unlock_irq (&dev->lock);
1135 				if (copy_from_user (dev->req->buf, buf, len))
1136 					retval = -EFAULT;
1137 				else {
1138 					if (len < dev->setup_wLength)
1139 						dev->req->zero = 1;
1140 					retval = usb_ep_queue (
1141 						dev->gadget->ep0, dev->req,
1142 						GFP_KERNEL);
1143 				}
1144 				spin_lock_irq(&dev->lock);
1145 				if (retval < 0) {
1146 					clean_req (dev->gadget->ep0, dev->req);
1147 				} else
1148 					retval = len;
1149 
1150 				return retval;
1151 			}
1152 
1153 		/* can stall some OUT transfers */
1154 		} else if (dev->setup_can_stall) {
1155 			VDEBUG(dev, "ep0out stall\n");
1156 			(void) usb_ep_set_halt (dev->gadget->ep0);
1157 			retval = -EL2HLT;
1158 			dev->state = STATE_DEV_CONNECTED;
1159 		} else {
1160 			DBG(dev, "bogus ep0out stall!\n");
1161 		}
1162 	} else
1163 		DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1164 
1165 	return retval;
1166 }
1167 
1168 static int
1169 ep0_fasync (int f, struct file *fd, int on)
1170 {
1171 	struct dev_data		*dev = fd->private_data;
1172 	// caller must F_SETOWN before signal delivery happens
1173 	VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1174 	return fasync_helper (f, fd, on, &dev->fasync);
1175 }
1176 
1177 static struct usb_gadget_driver gadgetfs_driver;
1178 
1179 static int
1180 dev_release (struct inode *inode, struct file *fd)
1181 {
1182 	struct dev_data		*dev = fd->private_data;
1183 
1184 	/* closing ep0 === shutdown all */
1185 
1186 	if (dev->gadget_registered)
1187 		usb_gadget_unregister_driver (&gadgetfs_driver);
1188 
1189 	/* at this point "good" hardware has disconnected the
1190 	 * device from USB; the host won't see it any more.
1191 	 * alternatively, all host requests will time out.
1192 	 */
1193 
1194 	kfree (dev->buf);
1195 	dev->buf = NULL;
1196 
1197 	/* other endpoints were all decoupled from this device */
1198 	spin_lock_irq(&dev->lock);
1199 	dev->state = STATE_DEV_DISABLED;
1200 	spin_unlock_irq(&dev->lock);
1201 
1202 	put_dev (dev);
1203 	return 0;
1204 }
1205 
1206 static unsigned int
1207 ep0_poll (struct file *fd, poll_table *wait)
1208 {
1209        struct dev_data         *dev = fd->private_data;
1210        int                     mask = 0;
1211 
1212 	if (dev->state <= STATE_DEV_OPENED)
1213 		return DEFAULT_POLLMASK;
1214 
1215        poll_wait(fd, &dev->wait, wait);
1216 
1217        spin_lock_irq (&dev->lock);
1218 
1219        /* report fd mode change before acting on it */
1220        if (dev->setup_abort) {
1221                dev->setup_abort = 0;
1222                mask = POLLHUP;
1223                goto out;
1224        }
1225 
1226        if (dev->state == STATE_DEV_SETUP) {
1227                if (dev->setup_in || dev->setup_can_stall)
1228                        mask = POLLOUT;
1229        } else {
1230                if (dev->ev_next != 0)
1231                        mask = POLLIN;
1232        }
1233 out:
1234        spin_unlock_irq(&dev->lock);
1235        return mask;
1236 }
1237 
1238 static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1239 {
1240 	struct dev_data		*dev = fd->private_data;
1241 	struct usb_gadget	*gadget = dev->gadget;
1242 	long ret = -ENOTTY;
1243 
1244 	if (gadget->ops->ioctl)
1245 		ret = gadget->ops->ioctl (gadget, code, value);
1246 
1247 	return ret;
1248 }
1249 
1250 /*----------------------------------------------------------------------*/
1251 
1252 /* The in-kernel gadget driver handles most ep0 issues, in particular
1253  * enumerating the single configuration (as provided from user space).
1254  *
1255  * Unrecognized ep0 requests may be handled in user space.
1256  */
1257 
1258 static void make_qualifier (struct dev_data *dev)
1259 {
1260 	struct usb_qualifier_descriptor		qual;
1261 	struct usb_device_descriptor		*desc;
1262 
1263 	qual.bLength = sizeof qual;
1264 	qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1265 	qual.bcdUSB = cpu_to_le16 (0x0200);
1266 
1267 	desc = dev->dev;
1268 	qual.bDeviceClass = desc->bDeviceClass;
1269 	qual.bDeviceSubClass = desc->bDeviceSubClass;
1270 	qual.bDeviceProtocol = desc->bDeviceProtocol;
1271 
1272 	/* assumes ep0 uses the same value for both speeds ... */
1273 	qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1274 
1275 	qual.bNumConfigurations = 1;
1276 	qual.bRESERVED = 0;
1277 
1278 	memcpy (dev->rbuf, &qual, sizeof qual);
1279 }
1280 
1281 static int
1282 config_buf (struct dev_data *dev, u8 type, unsigned index)
1283 {
1284 	int		len;
1285 	int		hs = 0;
1286 
1287 	/* only one configuration */
1288 	if (index > 0)
1289 		return -EINVAL;
1290 
1291 	if (gadget_is_dualspeed(dev->gadget)) {
1292 		hs = (dev->gadget->speed == USB_SPEED_HIGH);
1293 		if (type == USB_DT_OTHER_SPEED_CONFIG)
1294 			hs = !hs;
1295 	}
1296 	if (hs) {
1297 		dev->req->buf = dev->hs_config;
1298 		len = le16_to_cpu(dev->hs_config->wTotalLength);
1299 	} else {
1300 		dev->req->buf = dev->config;
1301 		len = le16_to_cpu(dev->config->wTotalLength);
1302 	}
1303 	((u8 *)dev->req->buf) [1] = type;
1304 	return len;
1305 }
1306 
1307 static int
1308 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1309 {
1310 	struct dev_data			*dev = get_gadget_data (gadget);
1311 	struct usb_request		*req = dev->req;
1312 	int				value = -EOPNOTSUPP;
1313 	struct usb_gadgetfs_event	*event;
1314 	u16				w_value = le16_to_cpu(ctrl->wValue);
1315 	u16				w_length = le16_to_cpu(ctrl->wLength);
1316 
1317 	spin_lock (&dev->lock);
1318 	dev->setup_abort = 0;
1319 	if (dev->state == STATE_DEV_UNCONNECTED) {
1320 		if (gadget_is_dualspeed(gadget)
1321 				&& gadget->speed == USB_SPEED_HIGH
1322 				&& dev->hs_config == NULL) {
1323 			spin_unlock(&dev->lock);
1324 			ERROR (dev, "no high speed config??\n");
1325 			return -EINVAL;
1326 		}
1327 
1328 		dev->state = STATE_DEV_CONNECTED;
1329 
1330 		INFO (dev, "connected\n");
1331 		event = next_event (dev, GADGETFS_CONNECT);
1332 		event->u.speed = gadget->speed;
1333 		ep0_readable (dev);
1334 
1335 	/* host may have given up waiting for response.  we can miss control
1336 	 * requests handled lower down (device/endpoint status and features);
1337 	 * then ep0_{read,write} will report the wrong status. controller
1338 	 * driver will have aborted pending i/o.
1339 	 */
1340 	} else if (dev->state == STATE_DEV_SETUP)
1341 		dev->setup_abort = 1;
1342 
1343 	req->buf = dev->rbuf;
1344 	req->context = NULL;
1345 	value = -EOPNOTSUPP;
1346 	switch (ctrl->bRequest) {
1347 
1348 	case USB_REQ_GET_DESCRIPTOR:
1349 		if (ctrl->bRequestType != USB_DIR_IN)
1350 			goto unrecognized;
1351 		switch (w_value >> 8) {
1352 
1353 		case USB_DT_DEVICE:
1354 			value = min (w_length, (u16) sizeof *dev->dev);
1355 			dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1356 			req->buf = dev->dev;
1357 			break;
1358 		case USB_DT_DEVICE_QUALIFIER:
1359 			if (!dev->hs_config)
1360 				break;
1361 			value = min (w_length, (u16)
1362 				sizeof (struct usb_qualifier_descriptor));
1363 			make_qualifier (dev);
1364 			break;
1365 		case USB_DT_OTHER_SPEED_CONFIG:
1366 			// FALLTHROUGH
1367 		case USB_DT_CONFIG:
1368 			value = config_buf (dev,
1369 					w_value >> 8,
1370 					w_value & 0xff);
1371 			if (value >= 0)
1372 				value = min (w_length, (u16) value);
1373 			break;
1374 		case USB_DT_STRING:
1375 			goto unrecognized;
1376 
1377 		default:		// all others are errors
1378 			break;
1379 		}
1380 		break;
1381 
1382 	/* currently one config, two speeds */
1383 	case USB_REQ_SET_CONFIGURATION:
1384 		if (ctrl->bRequestType != 0)
1385 			goto unrecognized;
1386 		if (0 == (u8) w_value) {
1387 			value = 0;
1388 			dev->current_config = 0;
1389 			usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1390 			// user mode expected to disable endpoints
1391 		} else {
1392 			u8	config, power;
1393 
1394 			if (gadget_is_dualspeed(gadget)
1395 					&& gadget->speed == USB_SPEED_HIGH) {
1396 				config = dev->hs_config->bConfigurationValue;
1397 				power = dev->hs_config->bMaxPower;
1398 			} else {
1399 				config = dev->config->bConfigurationValue;
1400 				power = dev->config->bMaxPower;
1401 			}
1402 
1403 			if (config == (u8) w_value) {
1404 				value = 0;
1405 				dev->current_config = config;
1406 				usb_gadget_vbus_draw(gadget, 2 * power);
1407 			}
1408 		}
1409 
1410 		/* report SET_CONFIGURATION like any other control request,
1411 		 * except that usermode may not stall this.  the next
1412 		 * request mustn't be allowed start until this finishes:
1413 		 * endpoints and threads set up, etc.
1414 		 *
1415 		 * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1416 		 * has bad/racey automagic that prevents synchronizing here.
1417 		 * even kernel mode drivers often miss them.
1418 		 */
1419 		if (value == 0) {
1420 			INFO (dev, "configuration #%d\n", dev->current_config);
1421 			usb_gadget_set_state(gadget, USB_STATE_CONFIGURED);
1422 			if (dev->usermode_setup) {
1423 				dev->setup_can_stall = 0;
1424 				goto delegate;
1425 			}
1426 		}
1427 		break;
1428 
1429 #ifndef	CONFIG_USB_PXA25X
1430 	/* PXA automagically handles this request too */
1431 	case USB_REQ_GET_CONFIGURATION:
1432 		if (ctrl->bRequestType != 0x80)
1433 			goto unrecognized;
1434 		*(u8 *)req->buf = dev->current_config;
1435 		value = min (w_length, (u16) 1);
1436 		break;
1437 #endif
1438 
1439 	default:
1440 unrecognized:
1441 		VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1442 			dev->usermode_setup ? "delegate" : "fail",
1443 			ctrl->bRequestType, ctrl->bRequest,
1444 			w_value, le16_to_cpu(ctrl->wIndex), w_length);
1445 
1446 		/* if there's an ep0 reader, don't stall */
1447 		if (dev->usermode_setup) {
1448 			dev->setup_can_stall = 1;
1449 delegate:
1450 			dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1451 						? 1 : 0;
1452 			dev->setup_wLength = w_length;
1453 			dev->setup_out_ready = 0;
1454 			dev->setup_out_error = 0;
1455 			value = 0;
1456 
1457 			/* read DATA stage for OUT right away */
1458 			if (unlikely (!dev->setup_in && w_length)) {
1459 				value = setup_req (gadget->ep0, dev->req,
1460 							w_length);
1461 				if (value < 0)
1462 					break;
1463 
1464 				spin_unlock (&dev->lock);
1465 				value = usb_ep_queue (gadget->ep0, dev->req,
1466 							GFP_KERNEL);
1467 				spin_lock (&dev->lock);
1468 				if (value < 0) {
1469 					clean_req (gadget->ep0, dev->req);
1470 					break;
1471 				}
1472 
1473 				/* we can't currently stall these */
1474 				dev->setup_can_stall = 0;
1475 			}
1476 
1477 			/* state changes when reader collects event */
1478 			event = next_event (dev, GADGETFS_SETUP);
1479 			event->u.setup = *ctrl;
1480 			ep0_readable (dev);
1481 			spin_unlock (&dev->lock);
1482 			return 0;
1483 		}
1484 	}
1485 
1486 	/* proceed with data transfer and status phases? */
1487 	if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1488 		req->length = value;
1489 		req->zero = value < w_length;
1490 
1491 		spin_unlock (&dev->lock);
1492 		value = usb_ep_queue (gadget->ep0, req, GFP_KERNEL);
1493 		if (value < 0) {
1494 			DBG (dev, "ep_queue --> %d\n", value);
1495 			req->status = 0;
1496 		}
1497 		return value;
1498 	}
1499 
1500 	/* device stalls when value < 0 */
1501 	spin_unlock (&dev->lock);
1502 	return value;
1503 }
1504 
1505 static void destroy_ep_files (struct dev_data *dev)
1506 {
1507 	DBG (dev, "%s %d\n", __func__, dev->state);
1508 
1509 	/* dev->state must prevent interference */
1510 	spin_lock_irq (&dev->lock);
1511 	while (!list_empty(&dev->epfiles)) {
1512 		struct ep_data	*ep;
1513 		struct inode	*parent;
1514 		struct dentry	*dentry;
1515 
1516 		/* break link to FS */
1517 		ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1518 		list_del_init (&ep->epfiles);
1519 		dentry = ep->dentry;
1520 		ep->dentry = NULL;
1521 		parent = d_inode(dentry->d_parent);
1522 
1523 		/* break link to controller */
1524 		if (ep->state == STATE_EP_ENABLED)
1525 			(void) usb_ep_disable (ep->ep);
1526 		ep->state = STATE_EP_UNBOUND;
1527 		usb_ep_free_request (ep->ep, ep->req);
1528 		ep->ep = NULL;
1529 		wake_up (&ep->wait);
1530 		put_ep (ep);
1531 
1532 		spin_unlock_irq (&dev->lock);
1533 
1534 		/* break link to dcache */
1535 		inode_lock(parent);
1536 		d_delete (dentry);
1537 		dput (dentry);
1538 		inode_unlock(parent);
1539 
1540 		spin_lock_irq (&dev->lock);
1541 	}
1542 	spin_unlock_irq (&dev->lock);
1543 }
1544 
1545 
1546 static struct dentry *
1547 gadgetfs_create_file (struct super_block *sb, char const *name,
1548 		void *data, const struct file_operations *fops);
1549 
1550 static int activate_ep_files (struct dev_data *dev)
1551 {
1552 	struct usb_ep	*ep;
1553 	struct ep_data	*data;
1554 
1555 	gadget_for_each_ep (ep, dev->gadget) {
1556 
1557 		data = kzalloc(sizeof(*data), GFP_KERNEL);
1558 		if (!data)
1559 			goto enomem0;
1560 		data->state = STATE_EP_DISABLED;
1561 		mutex_init(&data->lock);
1562 		init_waitqueue_head (&data->wait);
1563 
1564 		strncpy (data->name, ep->name, sizeof (data->name) - 1);
1565 		atomic_set (&data->count, 1);
1566 		data->dev = dev;
1567 		get_dev (dev);
1568 
1569 		data->ep = ep;
1570 		ep->driver_data = data;
1571 
1572 		data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1573 		if (!data->req)
1574 			goto enomem1;
1575 
1576 		data->dentry = gadgetfs_create_file (dev->sb, data->name,
1577 				data, &ep_io_operations);
1578 		if (!data->dentry)
1579 			goto enomem2;
1580 		list_add_tail (&data->epfiles, &dev->epfiles);
1581 	}
1582 	return 0;
1583 
1584 enomem2:
1585 	usb_ep_free_request (ep, data->req);
1586 enomem1:
1587 	put_dev (dev);
1588 	kfree (data);
1589 enomem0:
1590 	DBG (dev, "%s enomem\n", __func__);
1591 	destroy_ep_files (dev);
1592 	return -ENOMEM;
1593 }
1594 
1595 static void
1596 gadgetfs_unbind (struct usb_gadget *gadget)
1597 {
1598 	struct dev_data		*dev = get_gadget_data (gadget);
1599 
1600 	DBG (dev, "%s\n", __func__);
1601 
1602 	spin_lock_irq (&dev->lock);
1603 	dev->state = STATE_DEV_UNBOUND;
1604 	spin_unlock_irq (&dev->lock);
1605 
1606 	destroy_ep_files (dev);
1607 	gadget->ep0->driver_data = NULL;
1608 	set_gadget_data (gadget, NULL);
1609 
1610 	/* we've already been disconnected ... no i/o is active */
1611 	if (dev->req)
1612 		usb_ep_free_request (gadget->ep0, dev->req);
1613 	DBG (dev, "%s done\n", __func__);
1614 	put_dev (dev);
1615 }
1616 
1617 static struct dev_data		*the_device;
1618 
1619 static int gadgetfs_bind(struct usb_gadget *gadget,
1620 		struct usb_gadget_driver *driver)
1621 {
1622 	struct dev_data		*dev = the_device;
1623 
1624 	if (!dev)
1625 		return -ESRCH;
1626 	if (0 != strcmp (CHIP, gadget->name)) {
1627 		pr_err("%s expected %s controller not %s\n",
1628 			shortname, CHIP, gadget->name);
1629 		return -ENODEV;
1630 	}
1631 
1632 	set_gadget_data (gadget, dev);
1633 	dev->gadget = gadget;
1634 	gadget->ep0->driver_data = dev;
1635 
1636 	/* preallocate control response and buffer */
1637 	dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1638 	if (!dev->req)
1639 		goto enomem;
1640 	dev->req->context = NULL;
1641 	dev->req->complete = epio_complete;
1642 
1643 	if (activate_ep_files (dev) < 0)
1644 		goto enomem;
1645 
1646 	INFO (dev, "bound to %s driver\n", gadget->name);
1647 	spin_lock_irq(&dev->lock);
1648 	dev->state = STATE_DEV_UNCONNECTED;
1649 	spin_unlock_irq(&dev->lock);
1650 	get_dev (dev);
1651 	return 0;
1652 
1653 enomem:
1654 	gadgetfs_unbind (gadget);
1655 	return -ENOMEM;
1656 }
1657 
1658 static void
1659 gadgetfs_disconnect (struct usb_gadget *gadget)
1660 {
1661 	struct dev_data		*dev = get_gadget_data (gadget);
1662 	unsigned long		flags;
1663 
1664 	spin_lock_irqsave (&dev->lock, flags);
1665 	if (dev->state == STATE_DEV_UNCONNECTED)
1666 		goto exit;
1667 	dev->state = STATE_DEV_UNCONNECTED;
1668 
1669 	INFO (dev, "disconnected\n");
1670 	next_event (dev, GADGETFS_DISCONNECT);
1671 	ep0_readable (dev);
1672 exit:
1673 	spin_unlock_irqrestore (&dev->lock, flags);
1674 }
1675 
1676 static void
1677 gadgetfs_suspend (struct usb_gadget *gadget)
1678 {
1679 	struct dev_data		*dev = get_gadget_data (gadget);
1680 
1681 	INFO (dev, "suspended from state %d\n", dev->state);
1682 	spin_lock (&dev->lock);
1683 	switch (dev->state) {
1684 	case STATE_DEV_SETUP:		// VERY odd... host died??
1685 	case STATE_DEV_CONNECTED:
1686 	case STATE_DEV_UNCONNECTED:
1687 		next_event (dev, GADGETFS_SUSPEND);
1688 		ep0_readable (dev);
1689 		/* FALLTHROUGH */
1690 	default:
1691 		break;
1692 	}
1693 	spin_unlock (&dev->lock);
1694 }
1695 
1696 static struct usb_gadget_driver gadgetfs_driver = {
1697 	.function	= (char *) driver_desc,
1698 	.bind		= gadgetfs_bind,
1699 	.unbind		= gadgetfs_unbind,
1700 	.setup		= gadgetfs_setup,
1701 	.reset		= gadgetfs_disconnect,
1702 	.disconnect	= gadgetfs_disconnect,
1703 	.suspend	= gadgetfs_suspend,
1704 
1705 	.driver	= {
1706 		.name		= (char *) shortname,
1707 	},
1708 };
1709 
1710 /*----------------------------------------------------------------------*/
1711 /* DEVICE INITIALIZATION
1712  *
1713  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1714  *     status = write (fd, descriptors, sizeof descriptors)
1715  *
1716  * That write establishes the device configuration, so the kernel can
1717  * bind to the controller ... guaranteeing it can handle enumeration
1718  * at all necessary speeds.  Descriptor order is:
1719  *
1720  * . message tag (u32, host order) ... for now, must be zero; it
1721  *	would change to support features like multi-config devices
1722  * . full/low speed config ... all wTotalLength bytes (with interface,
1723  *	class, altsetting, endpoint, and other descriptors)
1724  * . high speed config ... all descriptors, for high speed operation;
1725  *	this one's optional except for high-speed hardware
1726  * . device descriptor
1727  *
1728  * Endpoints are not yet enabled. Drivers must wait until device
1729  * configuration and interface altsetting changes create
1730  * the need to configure (or unconfigure) them.
1731  *
1732  * After initialization, the device stays active for as long as that
1733  * $CHIP file is open.  Events must then be read from that descriptor,
1734  * such as configuration notifications.
1735  */
1736 
1737 static int is_valid_config (struct usb_config_descriptor *config)
1738 {
1739 	return config->bDescriptorType == USB_DT_CONFIG
1740 		&& config->bLength == USB_DT_CONFIG_SIZE
1741 		&& config->bConfigurationValue != 0
1742 		&& (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1743 		&& (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1744 	/* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1745 	/* FIXME check lengths: walk to end */
1746 }
1747 
1748 static ssize_t
1749 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1750 {
1751 	struct dev_data		*dev = fd->private_data;
1752 	ssize_t			value = len, length = len;
1753 	unsigned		total;
1754 	u32			tag;
1755 	char			*kbuf;
1756 
1757 	spin_lock_irq(&dev->lock);
1758 	if (dev->state > STATE_DEV_OPENED) {
1759 		value = ep0_write(fd, buf, len, ptr);
1760 		spin_unlock_irq(&dev->lock);
1761 		return value;
1762 	}
1763 	spin_unlock_irq(&dev->lock);
1764 
1765 	if (len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4))
1766 		return -EINVAL;
1767 
1768 	/* we might need to change message format someday */
1769 	if (copy_from_user (&tag, buf, 4))
1770 		return -EFAULT;
1771 	if (tag != 0)
1772 		return -EINVAL;
1773 	buf += 4;
1774 	length -= 4;
1775 
1776 	kbuf = memdup_user(buf, length);
1777 	if (IS_ERR(kbuf))
1778 		return PTR_ERR(kbuf);
1779 
1780 	spin_lock_irq (&dev->lock);
1781 	value = -EINVAL;
1782 	if (dev->buf)
1783 		goto fail;
1784 	dev->buf = kbuf;
1785 
1786 	/* full or low speed config */
1787 	dev->config = (void *) kbuf;
1788 	total = le16_to_cpu(dev->config->wTotalLength);
1789 	if (!is_valid_config (dev->config) || total >= length)
1790 		goto fail;
1791 	kbuf += total;
1792 	length -= total;
1793 
1794 	/* optional high speed config */
1795 	if (kbuf [1] == USB_DT_CONFIG) {
1796 		dev->hs_config = (void *) kbuf;
1797 		total = le16_to_cpu(dev->hs_config->wTotalLength);
1798 		if (!is_valid_config (dev->hs_config) || total >= length)
1799 			goto fail;
1800 		kbuf += total;
1801 		length -= total;
1802 	}
1803 
1804 	/* could support multiple configs, using another encoding! */
1805 
1806 	/* device descriptor (tweaked for paranoia) */
1807 	if (length != USB_DT_DEVICE_SIZE)
1808 		goto fail;
1809 	dev->dev = (void *)kbuf;
1810 	if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1811 			|| dev->dev->bDescriptorType != USB_DT_DEVICE
1812 			|| dev->dev->bNumConfigurations != 1)
1813 		goto fail;
1814 	dev->dev->bNumConfigurations = 1;
1815 	dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1816 
1817 	/* triggers gadgetfs_bind(); then we can enumerate. */
1818 	spin_unlock_irq (&dev->lock);
1819 	if (dev->hs_config)
1820 		gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1821 	else
1822 		gadgetfs_driver.max_speed = USB_SPEED_FULL;
1823 
1824 	value = usb_gadget_probe_driver(&gadgetfs_driver);
1825 	if (value != 0) {
1826 		kfree (dev->buf);
1827 		dev->buf = NULL;
1828 	} else {
1829 		/* at this point "good" hardware has for the first time
1830 		 * let the USB the host see us.  alternatively, if users
1831 		 * unplug/replug that will clear all the error state.
1832 		 *
1833 		 * note:  everything running before here was guaranteed
1834 		 * to choke driver model style diagnostics.  from here
1835 		 * on, they can work ... except in cleanup paths that
1836 		 * kick in after the ep0 descriptor is closed.
1837 		 */
1838 		value = len;
1839 		dev->gadget_registered = true;
1840 	}
1841 	return value;
1842 
1843 fail:
1844 	spin_unlock_irq (&dev->lock);
1845 	pr_debug ("%s: %s fail %Zd, %p\n", shortname, __func__, value, dev);
1846 	kfree (dev->buf);
1847 	dev->buf = NULL;
1848 	return value;
1849 }
1850 
1851 static int
1852 dev_open (struct inode *inode, struct file *fd)
1853 {
1854 	struct dev_data		*dev = inode->i_private;
1855 	int			value = -EBUSY;
1856 
1857 	spin_lock_irq(&dev->lock);
1858 	if (dev->state == STATE_DEV_DISABLED) {
1859 		dev->ev_next = 0;
1860 		dev->state = STATE_DEV_OPENED;
1861 		fd->private_data = dev;
1862 		get_dev (dev);
1863 		value = 0;
1864 	}
1865 	spin_unlock_irq(&dev->lock);
1866 	return value;
1867 }
1868 
1869 static const struct file_operations ep0_operations = {
1870 	.llseek =	no_llseek,
1871 
1872 	.open =		dev_open,
1873 	.read =		ep0_read,
1874 	.write =	dev_config,
1875 	.fasync =	ep0_fasync,
1876 	.poll =		ep0_poll,
1877 	.unlocked_ioctl = dev_ioctl,
1878 	.release =	dev_release,
1879 };
1880 
1881 /*----------------------------------------------------------------------*/
1882 
1883 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1884  *
1885  * Mounting the filesystem creates a controller file, used first for
1886  * device configuration then later for event monitoring.
1887  */
1888 
1889 
1890 /* FIXME PAM etc could set this security policy without mount options
1891  * if epfiles inherited ownership and permissons from ep0 ...
1892  */
1893 
1894 static unsigned default_uid;
1895 static unsigned default_gid;
1896 static unsigned default_perm = S_IRUSR | S_IWUSR;
1897 
1898 module_param (default_uid, uint, 0644);
1899 module_param (default_gid, uint, 0644);
1900 module_param (default_perm, uint, 0644);
1901 
1902 
1903 static struct inode *
1904 gadgetfs_make_inode (struct super_block *sb,
1905 		void *data, const struct file_operations *fops,
1906 		int mode)
1907 {
1908 	struct inode *inode = new_inode (sb);
1909 
1910 	if (inode) {
1911 		inode->i_ino = get_next_ino();
1912 		inode->i_mode = mode;
1913 		inode->i_uid = make_kuid(&init_user_ns, default_uid);
1914 		inode->i_gid = make_kgid(&init_user_ns, default_gid);
1915 		inode->i_atime = inode->i_mtime = inode->i_ctime
1916 				= CURRENT_TIME;
1917 		inode->i_private = data;
1918 		inode->i_fop = fops;
1919 	}
1920 	return inode;
1921 }
1922 
1923 /* creates in fs root directory, so non-renamable and non-linkable.
1924  * so inode and dentry are paired, until device reconfig.
1925  */
1926 static struct dentry *
1927 gadgetfs_create_file (struct super_block *sb, char const *name,
1928 		void *data, const struct file_operations *fops)
1929 {
1930 	struct dentry	*dentry;
1931 	struct inode	*inode;
1932 
1933 	dentry = d_alloc_name(sb->s_root, name);
1934 	if (!dentry)
1935 		return NULL;
1936 
1937 	inode = gadgetfs_make_inode (sb, data, fops,
1938 			S_IFREG | (default_perm & S_IRWXUGO));
1939 	if (!inode) {
1940 		dput(dentry);
1941 		return NULL;
1942 	}
1943 	d_add (dentry, inode);
1944 	return dentry;
1945 }
1946 
1947 static const struct super_operations gadget_fs_operations = {
1948 	.statfs =	simple_statfs,
1949 	.drop_inode =	generic_delete_inode,
1950 };
1951 
1952 static int
1953 gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
1954 {
1955 	struct inode	*inode;
1956 	struct dev_data	*dev;
1957 
1958 	if (the_device)
1959 		return -ESRCH;
1960 
1961 	CHIP = usb_get_gadget_udc_name();
1962 	if (!CHIP)
1963 		return -ENODEV;
1964 
1965 	/* superblock */
1966 	sb->s_blocksize = PAGE_SIZE;
1967 	sb->s_blocksize_bits = PAGE_SHIFT;
1968 	sb->s_magic = GADGETFS_MAGIC;
1969 	sb->s_op = &gadget_fs_operations;
1970 	sb->s_time_gran = 1;
1971 
1972 	/* root inode */
1973 	inode = gadgetfs_make_inode (sb,
1974 			NULL, &simple_dir_operations,
1975 			S_IFDIR | S_IRUGO | S_IXUGO);
1976 	if (!inode)
1977 		goto Enomem;
1978 	inode->i_op = &simple_dir_inode_operations;
1979 	if (!(sb->s_root = d_make_root (inode)))
1980 		goto Enomem;
1981 
1982 	/* the ep0 file is named after the controller we expect;
1983 	 * user mode code can use it for sanity checks, like we do.
1984 	 */
1985 	dev = dev_new ();
1986 	if (!dev)
1987 		goto Enomem;
1988 
1989 	dev->sb = sb;
1990 	dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
1991 	if (!dev->dentry) {
1992 		put_dev(dev);
1993 		goto Enomem;
1994 	}
1995 
1996 	/* other endpoint files are available after hardware setup,
1997 	 * from binding to a controller.
1998 	 */
1999 	the_device = dev;
2000 	return 0;
2001 
2002 Enomem:
2003 	return -ENOMEM;
2004 }
2005 
2006 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2007 static struct dentry *
2008 gadgetfs_mount (struct file_system_type *t, int flags,
2009 		const char *path, void *opts)
2010 {
2011 	return mount_single (t, flags, opts, gadgetfs_fill_super);
2012 }
2013 
2014 static void
2015 gadgetfs_kill_sb (struct super_block *sb)
2016 {
2017 	kill_litter_super (sb);
2018 	if (the_device) {
2019 		put_dev (the_device);
2020 		the_device = NULL;
2021 	}
2022 	kfree(CHIP);
2023 	CHIP = NULL;
2024 }
2025 
2026 /*----------------------------------------------------------------------*/
2027 
2028 static struct file_system_type gadgetfs_type = {
2029 	.owner		= THIS_MODULE,
2030 	.name		= shortname,
2031 	.mount		= gadgetfs_mount,
2032 	.kill_sb	= gadgetfs_kill_sb,
2033 };
2034 MODULE_ALIAS_FS("gadgetfs");
2035 
2036 /*----------------------------------------------------------------------*/
2037 
2038 static int __init init (void)
2039 {
2040 	int status;
2041 
2042 	status = register_filesystem (&gadgetfs_type);
2043 	if (status == 0)
2044 		pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2045 			shortname, driver_desc);
2046 	return status;
2047 }
2048 module_init (init);
2049 
2050 static void __exit cleanup (void)
2051 {
2052 	pr_debug ("unregister %s\n", shortname);
2053 	unregister_filesystem (&gadgetfs_type);
2054 }
2055 module_exit (cleanup);
2056 
2057