1/*
2 * <linux/usb_gadget.h>
3 *
4 * We call the USB code inside a Linux-based peripheral device a "gadget"
5 * driver, except for the hardware-specific bus glue.  One USB host can
6 * master many USB gadgets, but the gadgets are only slaved to one host.
7 *
8 *
9 * (c) Copyright 2002-2003 by David Brownell
10 * All Rights Reserved.
11 *
12 * This software is licensed under the GNU GPL version 2.
13 *
14 * ALTERNATIVELY, the kernel API documentation which is included in this
15 * software may also be licenced under the "GNU Free Documentation
16 * License" (version 1.2 or, at your choice, any later version), when
17 * used as part of the "USB Gadget API for Linux" documentation.
18 */
19
20#ifndef __LINUX_USB_GADGET_H
21#define __LINUX_USB_GADGET_H
22
23#ifdef __KERNEL__
24
25struct usb_ep;
26
27/**
28 * struct usb_request - describes one i/o request
29 * @buf: Buffer used for data.  Always provide this; some controllers
30 * 	only use PIO, or don't use DMA for some endpoints.
31 * @dma: DMA address corresponding to 'buf'.  If you don't set this
32 * 	field, and the usb controller needs one, it is responsible
33 * 	for mapping and unmapping the buffer.
34 * @length: Length of that data
35 * @no_interrupt: If true, hints that no completion irq is needed.
36 *	Helpful sometimes with deep request queues.
37 * @zero: If true, when writing data, makes the last packet be "short"
38 *     by adding a zero length packet as needed;
39 * @short_not_ok: When reading data, makes short packets be
40 *     treated as errors (queue stops advancing till cleanup).
41 * @complete: Function called when request completes
42 * @context: For use by the completion callback
43 * @list: For use by the gadget driver.
44 * @status: Reports completion code, zero or a negative errno.
45 * 	Normally, faults block the transfer queue from advancing until
46 * 	the completion callback returns.
47 * 	Code "-ESHUTDOWN" indicates completion caused by device disconnect,
48 * 	or when the driver disabled the endpoint.
49 * @actual: Reports actual bytes transferred.  For reads (OUT
50 * 	transfers) this may be less than the requested length.  If the
51 * 	short_not_ok flag is set, short reads are treated as errors
52 * 	even when status otherwise indicates successful completion.
53 * 	Note that for writes (IN transfers) the data bytes may still
54 * 	reside in a device-side FIFO.
55 *
56 * These are allocated/freed through the endpoint they're used with.  The
57 * hardware's driver can add extra per-request data to the memory it returns,
58 * which often avoids separate memory allocations (potential failures),
59 * later when the request is queued.
60 *
61 * Request flags affect request handling, such as whether a zero length
62 * packet is written (the "zero" flag), whether a short read should be
63 * treated as an error (blocking request queue advance, the "short_not_ok"
64 * flag), or hinting that an interrupt is not required (the "no_interrupt"
65 * flag, for use with deep request queues).
66 *
67 * Bulk endpoints can use any size buffers, and can also be used for interrupt
68 * transfers. interrupt-only endpoints can be much less functional.
69 */
70	// NOTE this is analagous to 'struct urb' on the host side,
71	// except that it's thinner and promotes more pre-allocation.
72	//
73	// ISSUE should this be allocated through the device?
74
75struct usb_request {
76	void			*buf;
77	unsigned		length;
78	dma_addr_t		dma;
79
80	unsigned		no_interrupt : 1,
81				zero : 1,
82				short_not_ok : 1;
83
84	void			(*complete)(struct usb_ep *ep,
85					struct usb_request *req);
86	void			*context;
87	struct list_head	list;
88
89	int			status;
90	unsigned		actual;
91};
92
93/*-------------------------------------------------------------------------*/
94
95/* endpoint-specific parts of the api to the usb controller hardware.
96 * unlike the urb model, (de)multiplexing layers are not required.
97 * (so this api could slash overhead if used on the host side...)
98 *
99 * note that device side usb controllers commonly differ in how many
100 * endpoints they support, as well as their capabilities.
101 */
102struct usb_ep_ops {
103	int (*enable) (struct usb_ep *ep,
104		const struct usb_endpoint_descriptor *desc);
105	int (*disable) (struct usb_ep *ep);
106
107	struct usb_request *(*alloc_request) (struct usb_ep *ep,
108		int gfp_flags);
109	void (*free_request) (struct usb_ep *ep, struct usb_request *req);
110
111	void *(*alloc_buffer) (struct usb_ep *ep, unsigned bytes,
112		dma_addr_t *dma, int gfp_flags);
113	void (*free_buffer) (struct usb_ep *ep, void *buf, dma_addr_t dma,
114		unsigned bytes);
115	// NOTE:  on 2.5, drivers may also use dma_map() and
116	// dma_sync_single() to manage dma overhead.
117
118	int (*queue) (struct usb_ep *ep, struct usb_request *req,
119		int gfp_flags);
120	int (*dequeue) (struct usb_ep *ep, struct usb_request *req);
121
122	int (*set_halt) (struct usb_ep *ep, int value);
123	int (*fifo_status) (struct usb_ep *ep);
124	void (*fifo_flush) (struct usb_ep *ep);
125};
126
127/**
128 * struct usb_ep - device side representation of USB endpoint
129 * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
130 * @ep_list:the gadget's ep_list holds all of its endpoints
131 * @maxpacket:the maximum packet size used on this endpoint, as
132 * 	configured when the endpoint was enabled.
133 * @driver_data:for use by the gadget driver.  all other fields are
134 * 	read-only to gadget drivers.
135 *
136 * the bus controller driver lists all the general purpose endpoints in
137 * gadget->ep_list.  the control endpoint (gadget->ep0) is not in that list,
138 * and is accessed only in response to a driver setup() callback.
139 */
140struct usb_ep {
141	void			*driver_data;
142
143	const char		*name;
144	const struct usb_ep_ops	*ops;
145	struct list_head	ep_list;
146	unsigned		maxpacket : 16;
147};
148
149/*-------------------------------------------------------------------------*/
150
151/**
152 * usb_ep_enable - configure endpoint, making it usable
153 * @ep:the endpoint being configured.  may not be the endpoint named "ep0".
154 * 	drivers discover endpoints through the ep_list of a usb_gadget.
155 * @desc:descriptor for desired behavior.  caller guarantees this pointer
156 * 	remains valid until the endpoint is disabled; the data byte order
157 * 	is little-endian (usb-standard).
158 *
159 * when configurations are set, or when interface settings change, the driver
160 * will enable or disable the relevant endpoints.  while it is enabled, an
161 * endpoint may be used for i/o until the driver receives a disconnect() from
162 * the host or until the endpoint is disabled.
163 *
164 * the ep0 implementation (which calls this routine) must ensure that the
165 * hardware capabilities of each endpoint match the descriptor provided
166 * for it.  for example, an endpoint named "ep2in-bulk" would be usable
167 * for interrupt transfers as well as bulk, but it likely couldn't be used
168 * for iso transfers or for endpoint 14.  some endpoints are fully
169 * configurable, with more generic names like "ep-a".  (remember that for
170 * USB, "in" means "towards the USB master".)
171 *
172 * returns zero, or a negative error code.
173 */
174static inline int
175usb_ep_enable (struct usb_ep *ep, const struct usb_endpoint_descriptor *desc)
176{
177	return ep->ops->enable (ep, desc);
178}
179
180/**
181 * usb_ep_disable - endpoint is no longer usable
182 * @ep:the endpoint being unconfigured.  may not be the endpoint named "ep0".
183 *
184 * no other task may be using this endpoint when this is called.
185 * any pending and uncompleted requests will complete with status
186 * indicating disconnect (-ESHUTDOWN) before this call returns.
187 * gadget drivers must call usb_ep_enable() again before queueing
188 * requests to the endpoint.
189 *
190 * returns zero, or a negative error code.
191 */
192static inline int
193usb_ep_disable (struct usb_ep *ep)
194{
195	return ep->ops->disable (ep);
196}
197
198/**
199 * usb_ep_alloc_request - allocate a request object to use with this endpoint
200 * @ep:the endpoint to be used with with the request
201 * @gfp_flags:GFP_* flags to use
202 *
203 * Request objects must be allocated with this call, since they normally
204 * need controller-specific setup and may even need endpoint-specific
205 * resources such as allocation of DMA descriptors.
206 * Requests may be submitted with usb_ep_queue(), and receive a single
207 * completion callback.  Free requests with usb_ep_free_request(), when
208 * they are no longer needed.
209 *
210 * Returns the request, or null if one could not be allocated.
211 */
212static inline struct usb_request *
213usb_ep_alloc_request (struct usb_ep *ep, int gfp_flags)
214{
215	return ep->ops->alloc_request (ep, gfp_flags);
216}
217
218/**
219 * usb_ep_free_request - frees a request object
220 * @ep:the endpoint associated with the request
221 * @req:the request being freed
222 *
223 * Reverses the effect of usb_ep_alloc_request().
224 * Caller guarantees the request is not queued, and that it will
225 * no longer be requeued (or otherwise used).
226 */
227static inline void
228usb_ep_free_request (struct usb_ep *ep, struct usb_request *req)
229{
230	ep->ops->free_request (ep, req);
231}
232
233/**
234 * usb_ep_alloc_buffer - allocate an I/O buffer
235 * @ep:the endpoint associated with the buffer
236 * @len:length of the desired buffer
237 * @dma:pointer to the buffer's DMA address; must be valid
238 * @gfp_flags:GFP_* flags to use
239 *
240 * Returns a new buffer, or null if one could not be allocated.
241 * The buffer is suitably aligned for dma, if that endpoint uses DMA,
242 * and the caller won't have to care about dma-inconsistency
243 * or any hidden "bounce buffer" mechanism.  No additional per-request
244 * DMA mapping will be required for such buffers.
245 * Free it later with usb_ep_free_buffer().
246 *
247 * You don't need to use this call to allocate I/O buffers unless you
248 * want to make sure drivers don't incur costs for such "bounce buffer"
249 * copies or per-request DMA mappings.
250 */
251static inline void *
252usb_ep_alloc_buffer (struct usb_ep *ep, unsigned len, dma_addr_t *dma,
253	int gfp_flags)
254{
255	return ep->ops->alloc_buffer (ep, len, dma, gfp_flags);
256}
257
258/**
259 * usb_ep_free_buffer - frees an i/o buffer
260 * @ep:the endpoint associated with the buffer
261 * @buf:CPU view address of the buffer
262 * @dma:the buffer's DMA address
263 * @len:length of the buffer
264 *
265 * reverses the effect of usb_ep_alloc_buffer().
266 * caller guarantees the buffer will no longer be accessed
267 */
268static inline void
269usb_ep_free_buffer (struct usb_ep *ep, void *buf, dma_addr_t dma, unsigned len)
270{
271	ep->ops->free_buffer (ep, buf, dma, len);
272}
273
274/**
275 * usb_ep_queue - queues (submits) an I/O request to an endpoint.
276 * @ep:the endpoint associated with the request
277 * @req:the request being submitted
278 * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
279 * 	pre-allocate all necessary memory with the request.
280 *
281 * This tells the device controller to perform the specified request through
282 * that endpoint (reading or writing a buffer).  When the request completes,
283 * including being canceled by usb_ep_dequeue(), the request's completion
284 * routine is called to return the request to the driver.  Any endpoint
285 * (except control endpoints like ep0) may have more than one transfer
286 * request queued; they complete in FIFO order.  Once a gadget driver
287 * submits a request, that request may not be examined or modified until it
288 * is given back to that driver through the completion callback.
289 *
290 * Each request is turned into one or more packets.  The controller driver
291 * never merges adjacent requests into the same packet.  OUT transfers
292 * will sometimes use data that's already buffered in the hardware.
293 *
294 * Bulk endpoints can queue any amount of data; the transfer is packetized
295 * automatically.  The last packet will be short if the request doesn't fill it
296 * out completely.  Zero length packets (ZLPs) should be avoided in portable
297 * protocols since not all usb hardware can successfully handle zero length
298 * packets.  (ZLPs may be explicitly written, and may be implicitly written if
299 * the request 'zero' flag is set.)  Bulk endpoints may also be used
300 * for interrupt transfers; but the reverse is not true, and some endpoints
301 * won't support every interrupt transfer.  (Such as 768 byte packets.)
302 *
303 * Interrupt-only endpoints are less functional than bulk endpoints, for
304 * example by not supporting queueing or not handling buffers that are
305 * larger than the endpoint's maxpacket size.  They may also treat data
306 * toggle differently.
307 *
308 * Control endpoints ... after getting a setup() callback, the driver queues
309 * one response (optional if it would be zero length).  That enables the
310 * status ack, after transfering data as specified in the response.  Setup
311 * functions may return negative error codes to generate protocol stalls.
312 *
313 * For periodic endpoints, like interrupt or isochronous ones, the usb host
314 * arranges to poll once per interval, and the gadget driver usually will
315 * have queued some data to transfer at that time.
316 *
317 * Returns zero, or a negative error code.  Endpoints that are not enabled,
318 * or which are enabled but halted, report errors; errors will also be
319 * reported when the usb peripheral is disconnected.
320 */
321static inline int
322usb_ep_queue (struct usb_ep *ep, struct usb_request *req, int gfp_flags)
323{
324	return ep->ops->queue (ep, req, gfp_flags);
325}
326
327/**
328 * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
329 * @ep:the endpoint associated with the request
330 * @req:the request being canceled
331 *
332 * if the request is still active on the endpoint, it is dequeued and its
333 * completion routine is called (with status -ECONNRESET); else a negative
334 * error code is returned.
335 *
336 * note that some hardware can't clear out write fifos (to unlink the request
337 * at the head of the queue) except as part of disconnecting from usb.  such
338 * restrictions prevent drivers from supporting configuration changes,
339 * even to configuration zero (a "chapter 9" requirement).
340 */
341static inline int usb_ep_dequeue (struct usb_ep *ep, struct usb_request *req)
342{
343	return ep->ops->dequeue (ep, req);
344}
345
346/**
347 * usb_ep_set_halt - sets the endpoint halt feature.
348 * @ep: the non-isochronous endpoint being stalled
349 *
350 * Use this to stall an endpoint, perhaps as an error report.
351 * Except for control endpoints,
352 * the endpoint stays halted (will not stream any data) until the host
353 * clears this feature; drivers may need to empty the endpoint's request
354 * queue first, to make sure no inappropriate transfers happen.
355 *
356 * Returns zero, or a negative error code.  On success, this call sets
357 * underlying hardware state that blocks data transfers.
358 */
359static inline int
360usb_ep_set_halt (struct usb_ep *ep)
361{
362	return ep->ops->set_halt (ep, 1);
363}
364
365/**
366 * usb_ep_clear_halt - clears endpoint halt, and resets toggle
367 * @ep:the bulk or interrupt endpoint being reset
368 *
369 * use this when responding to the standard usb "set interface" request,
370 * for endpoints that aren't reconfigured, after clearing any other state
371 * in the endpoint's i/o queue.
372 *
373 * returns zero, or a negative error code.  on success, this call clears
374 * the underlying hardware state reflecting endpoint halt and data toggle.
375 */
376static inline int
377usb_ep_clear_halt (struct usb_ep *ep)
378{
379	return ep->ops->set_halt (ep, 0);
380}
381
382/**
383 * usb_ep_fifo_status - returns number of bytes in fifo, or error
384 * @ep: the endpoint whose fifo status is being checked.
385 *
386 * FIFO endpoints may have "unclaimed data" in them in certain cases,
387 * such as after aborted transfers.  Hosts may not have collected all
388 * the IN data written by the gadget driver, as reported by a request
389 * completion.  The gadget driver may not have collected all the data
390 * written OUT to it by the host.  Drivers that need precise handling for
391 * fault reporting or recovery may need to use this call.
392 *
393 * This returns the number of such bytes in the fifo, or a negative
394 * errno if the endpoint doesn't use a FIFO or doesn't support such
395 * precise handling.
396 */
397static inline int
398usb_ep_fifo_status (struct usb_ep *ep)
399{
400	if (ep->ops->fifo_status)
401		return ep->ops->fifo_status (ep);
402	else
403		return -EOPNOTSUPP;
404}
405
406/**
407 * usb_ep_fifo_flush - flushes contents of a fifo
408 * @ep: the endpoint whose fifo is being flushed.
409 *
410 * This call may be used to flush the "unclaimed data" that may exist in
411 * an endpoint fifo after abnormal transaction terminations.  The call
412 * must never be used except when endpoint is not being used for any
413 * protocol translation.
414 */
415static inline void
416usb_ep_fifo_flush (struct usb_ep *ep)
417{
418	if (ep->ops->fifo_flush)
419		ep->ops->fifo_flush (ep);
420}
421
422
423/*-------------------------------------------------------------------------*/
424
425struct usb_gadget;
426
427/* the rest of the api to the controller hardware: device operations,
428 * which don't involve endpoints (or i/o).
429 */
430struct usb_gadget_ops {
431	int	(*get_frame)(struct usb_gadget *);
432	int	(*wakeup)(struct usb_gadget *);
433	int	(*set_selfpowered) (struct usb_gadget *, int value);
434	int	(*ioctl)(struct usb_gadget *,
435				unsigned code, unsigned long param);
436};
437
438/**
439 * struct usb_gadget - represents a usb slave device
440 * @ep0: Endpoint zero, used when reading or writing responses to
441 * 	driver setup() requests
442 * @ep_list: List of other endpoints supported by the device.
443 * @speed: Speed of current connection to USB host.
444 * @name: Identifies the controller hardware type.  Used in diagnostics
445 * 	and sometimes configuration.
446 *
447 * Gadgets have a mostly-portable "gadget driver" implementing device
448 * functions, handling all usb configurations and interfaces.  They
449 * also have a hardware-specific driver (accessed through ops vectors),
450 * which insulates the gadget driver from hardware details and packages
451 * the hardware endpoints through generic i/o queues.
452 *
453 * Except for the driver data, all fields in this structure are
454 * read-only to the gadget driver.  That driver data is part of the
455 * "driver model" infrastructure in 2.5 (and later) kernels, and for
456 * earlier systems is grouped in a similar structure that's not known
457 * to the rest of the kernel.
458 */
459struct usb_gadget {
460	/* readonly to gadget driver */
461	const struct usb_gadget_ops	*ops;
462	struct usb_ep			*ep0;
463	struct list_head		ep_list;	/* of usb_ep */
464	enum usb_device_speed		speed;
465	const char			*name;
466
467	struct __gadget_device {
468		const char		*bus_id;
469		void			*driver_data;
470	} dev;
471};
472
473static inline void set_gadget_data (struct usb_gadget *gadget, void *data)
474	{ gadget->dev.driver_data = data; }
475static inline void *get_gadget_data (struct usb_gadget *gadget)
476	{ return gadget->dev.driver_data; }
477
478
479/* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
480#define gadget_for_each_ep(tmp,gadget) \
481	list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
482
483#ifndef list_for_each_entry
484/* not available in 2.4.18 */
485#define list_for_each_entry(pos, head, member)				\
486	for (pos = list_entry((head)->next, typeof(*pos), member),	\
487		     prefetch(pos->member.next);			\
488	     &pos->member != (head); 					\
489	     pos = list_entry(pos->member.next, typeof(*pos), member),	\
490		     prefetch(pos->member.next))
491#endif
492
493
494/**
495 * usb_gadget_frame_number - returns the current frame number
496 * @gadget: controller that reports the frame number
497 *
498 * Returns the usb frame number, normally eleven bits from a SOF packet,
499 * or negative errno if this device doesn't support this capability.
500 */
501static inline int usb_gadget_frame_number (struct usb_gadget *gadget)
502{
503	return gadget->ops->get_frame (gadget);
504}
505
506/**
507 * usb_gadget_wakeup - tries to wake up the host connected to this gadget
508 * @gadget: controller used to wake up the host
509 *
510 * Returns zero on success, else negative error code if the hardware
511 * doesn't support such attempts, or its support has not been enabled
512 * by the usb host.  Drivers must return device descriptors that report
513 * their ability to support this, or hosts won't enable it.
514 */
515static inline int usb_gadget_wakeup (struct usb_gadget *gadget)
516{
517	if (!gadget->ops->wakeup)
518		return -EOPNOTSUPP;
519	return gadget->ops->wakeup (gadget);
520}
521
522/**
523 * usb_gadget_set_selfpowered - sets the device selfpowered feature.
524 * @gadget:the device being declared as self-powered
525 *
526 * this affects the device status reported by the hardware driver
527 * to reflect that it now has a local power supply.
528 *
529 * returns zero on success, else negative errno.
530 */
531static inline int
532usb_gadget_set_selfpowered (struct usb_gadget *gadget)
533{
534	if (!gadget->ops->set_selfpowered)
535		return -EOPNOTSUPP;
536	return gadget->ops->set_selfpowered (gadget, 1);
537}
538
539/**
540 * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
541 * @gadget:the device being declared as bus-powered
542 *
543 * this affects the device status reported by the hardware driver.
544 * some hardware may not support bus-powered operation, in which
545 * case this feature's value can never change.
546 *
547 * returns zero on success, else negative errno.
548 */
549static inline int
550usb_gadget_clear_selfpowered (struct usb_gadget *gadget)
551{
552	if (!gadget->ops->set_selfpowered)
553		return -EOPNOTSUPP;
554	return gadget->ops->set_selfpowered (gadget, 0);
555}
556
557
558/*-------------------------------------------------------------------------*/
559
560/**
561 * struct usb_gadget_driver - driver for usb 'slave' devices
562 * @function: String describing the gadget's function
563 * @speed: Highest speed the driver handles.
564 * @bind: Invoked when the driver is bound to a gadget, usually
565 * 	after registering the driver.
566 * 	At that point, ep0 is fully initialized, and ep_list holds
567 * 	the currently-available endpoints.
568 * 	Called in a context that permits sleeping.
569 * @setup: Invoked for ep0 control requests that aren't handled by
570 * 	the hardware level driver. Most calls must be handled by
571 * 	the gadget driver, including descriptor and configuration
572 * 	management.  The 16 bit members of the setup data are in
573 * 	cpu order. Called in_interrupt; this may not sleep.  Driver
574 *	queues a response to ep0, or returns negative to stall.
575 * @disconnect: Invoked after all transfers have been stopped,
576 * 	when the host is disconnected.  May be called in_interrupt; this
577 * 	may not sleep.
578 * @unbind: Invoked when the driver is unbound from a gadget,
579 * 	usually from rmmod (after a disconnect is reported).
580 * 	Called in a context that permits sleeping.
581 * @suspend: Invoked on USB suspend.  May be called in_interrupt.
582 * @resume: Invoked on USB resume.  May be called in_interrupt.
583 *
584 * Devices are disabled till a gadget driver successfully bind()s, which
585 * means the driver will handle setup() requests needed to enumerate (and
586 * meet "chapter 9" requirements) then do some useful work.
587 *
588 * Drivers use hardware-specific knowledge to configure the usb hardware.
589 * endpoint addressing is only one of several hardware characteristics that
590 * are in descriptors the ep0 implementation returns from setup() calls.
591 *
592 * Except for ep0 implementation, most driver code shouldn't need change to
593 * run on top of different usb controllers.  It'll use endpoints set up by
594 * that ep0 implementation.
595 *
596 * The usb controller driver handles a few standard usb requests.  Those
597 * include set_address, and feature flags for devices, interfaces, and
598 * endpoints (the get_status, set_feature, and clear_feature requests).
599 *
600 * Accordingly, the driver's setup() callback must always implement all
601 * get_descriptor requests, returning at least a device descriptor and
602 * a configuration descriptor.  Drivers must make sure the endpoint
603 * descriptors match any hardware constraints. Some hardware also constrains
604 * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
605 *
606 * The driver's setup() callback must also implement set_configuration,
607 * and should also implement set_interface, get_configuration, and
608 * get_interface.  Setting a configuration (or interface) is where
609 * endpoints should be activated or (config 0) shut down.
610 *
611 * (Note that only the default control endpoint is supported.  Neither
612 * hosts nor devices generally support control traffic except to ep0.)
613 *
614 * Most devices will ignore USB suspend/resume operations, and so will
615 * not provide those callbacks.  However, some may need to change modes
616 * when the host is not longer directing those activities.  For example,
617 * local controls (buttons, dials, etc) may need to be re-enabled since
618 * the (remote) host can't do that any longer.
619 */
620struct usb_gadget_driver {
621	char			*function;
622	enum usb_device_speed	speed;
623	int			(*bind)(struct usb_gadget *);
624	void			(*unbind)(struct usb_gadget *);
625	int			(*setup)(struct usb_gadget *,
626					const struct usb_ctrlrequest *);
627	void			(*disconnect)(struct usb_gadget *);
628	void			(*suspend)(struct usb_gadget *);
629	void			(*resume)(struct usb_gadget *);
630
631	// FIXME support safe rmmod
632	struct __gadget_driver {
633		const char	*name;
634		void		*driver_data;
635	} driver;
636};
637
638
639
640/*-------------------------------------------------------------------------*/
641
642/* driver modules register and unregister, as usual.
643 * these calls must be made in a context that can sleep.
644 *
645 * these will usually be implemented directly by the hardware-dependent
646 * usb bus interface driver, which will only support a single driver.
647 */
648
649/**
650 * usb_gadget_register_driver - register a gadget driver
651 * @driver:the driver being registered
652 *
653 * Call this in your gadget driver's module initialization function,
654 * to tell the underlying usb controller driver about your driver.
655 * The driver's bind() function will be called to bind it to a
656 * gadget.  This function must be called in a context that can sleep.
657 */
658int usb_gadget_register_driver (struct usb_gadget_driver *driver);
659
660/**
661 * usb_gadget_unregister_driver - unregister a gadget driver
662 * @driver:the driver being unregistered
663 *
664 * Call this in your gadget driver's module cleanup function,
665 * to tell the underlying usb controller that your driver is
666 * going away.  If the controller is connected to a USB host,
667 * it will first disconnect().  The driver is also requested
668 * to unbind() and clean up any device state, before this procedure
669 * finally returns.
670 * This function must be called in a context that can sleep.
671 */
672int usb_gadget_unregister_driver (struct usb_gadget_driver *driver);
673
674/*-------------------------------------------------------------------------*/
675
676/* utility to simplify dealing with string descriptors */
677
678/**
679 * struct usb_string - wraps a C string and its USB id
680 * @id:the (nonzero) ID for this string
681 * @s:the string, in ISO-8859/1 characters
682 *
683 * If you're using usb_gadget_get_string(), use this to wrap a string
684 * together with its ID.
685 */
686struct usb_string {
687	u8			id;
688	const char		*s;
689};
690
691/**
692 * struct usb_gadget_strings - a set of USB strings in a given language
693 * @language:identifies the strings' language (0x0409 for en-us)
694 * @strings:array of strings with their ids
695 *
696 * If you're using usb_gadget_get_string(), use this to wrap all the
697 * strings for a given language.
698 */
699struct usb_gadget_strings {
700	u16			language;	/* 0x0409 for en-us */
701	struct usb_string	*strings;
702};
703
704/* put descriptor for string with that id into buf (buflen >= 256) */
705int usb_gadget_get_string (struct usb_gadget_strings *table, int id, u8 *buf);
706
707
708#endif  /* __KERNEL__ */
709
710#endif	/* __LINUX_USB_GADGET_H */
711