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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 2002-2004 by David Brownell
10  * All Rights Reserved.
11  *
12  * This software is licensed under the GNU GPL version 2.
13  *
14  * Ported to U-Boot by: Thomas Smits <ts.smits@gmail.com> and
15  *                      Remy Bohmer <linux@bohmer.net>
16  */
17 
18 #ifndef __LINUX_USB_GADGET_H
19 #define __LINUX_USB_GADGET_H
20 
21 #include <errno.h>
22 #include <linux/compat.h>
23 #include <linux/list.h>
24 
25 struct 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  * @stream_id: The stream id, when USB3.0 bulk streams are being used
35  * @length: Length of that data
36  * @no_interrupt: If true, hints that no completion irq is needed.
37  *	Helpful sometimes with deep request queues that are handled
38  *	directly by DMA controllers.
39  * @zero: If true, when writing data, makes the last packet be "short"
40  *     by adding a zero length packet as needed;
41  * @short_not_ok: When reading data, makes short packets be
42  *     treated as errors (queue stops advancing till cleanup).
43  * @complete: Function called when request completes, so this request and
44  *	its buffer may be re-used.
45  *	Reads terminate with a short packet, or when the buffer fills,
46  *	whichever comes first.  When writes terminate, some data bytes
47  *	will usually still be in flight (often in a hardware fifo).
48  *	Errors (for reads or writes) stop the queue from advancing
49  *	until the completion function returns, so that any transfers
50  *	invalidated by the error may first be dequeued.
51  * @context: For use by the completion callback
52  * @list: For use by the gadget driver.
53  * @status: Reports completion code, zero or a negative errno.
54  *	Normally, faults block the transfer queue from advancing until
55  *	the completion callback returns.
56  *	Code "-ESHUTDOWN" indicates completion caused by device disconnect,
57  *	or when the driver disabled the endpoint.
58  * @actual: Reports bytes transferred to/from the buffer.  For reads (OUT
59  *	transfers) this may be less than the requested length.  If the
60  *	short_not_ok flag is set, short reads are treated as errors
61  *	even when status otherwise indicates successful completion.
62  *	Note that for writes (IN transfers) some data bytes may still
63  *	reside in a device-side FIFO when the request is reported as
64  *	complete.
65  *
66  * These are allocated/freed through the endpoint they're used with.  The
67  * hardware's driver can add extra per-request data to the memory it returns,
68  * which often avoids separate memory allocations (potential failures),
69  * later when the request is queued.
70  *
71  * Request flags affect request handling, such as whether a zero length
72  * packet is written (the "zero" flag), whether a short read should be
73  * treated as an error (blocking request queue advance, the "short_not_ok"
74  * flag), or hinting that an interrupt is not required (the "no_interrupt"
75  * flag, for use with deep request queues).
76  *
77  * Bulk endpoints can use any size buffers, and can also be used for interrupt
78  * transfers. interrupt-only endpoints can be much less functional.
79  *
80  * NOTE:  this is analagous to 'struct urb' on the host side, except that
81  * it's thinner and promotes more pre-allocation.
82  */
83 
84 struct usb_request {
85 	void			*buf;
86 	unsigned		length;
87 	dma_addr_t		dma;
88 
89 	unsigned		stream_id:16;
90 	unsigned		no_interrupt:1;
91 	unsigned		zero:1;
92 	unsigned		short_not_ok:1;
93 
94 	void			(*complete)(struct usb_ep *ep,
95 					struct usb_request *req);
96 	void			*context;
97 	struct list_head	list;
98 
99 	int			status;
100 	unsigned		actual;
101 };
102 
103 /*-------------------------------------------------------------------------*/
104 
105 /* endpoint-specific parts of the api to the usb controller hardware.
106  * unlike the urb model, (de)multiplexing layers are not required.
107  * (so this api could slash overhead if used on the host side...)
108  *
109  * note that device side usb controllers commonly differ in how many
110  * endpoints they support, as well as their capabilities.
111  */
112 struct usb_ep_ops {
113 	int (*enable) (struct usb_ep *ep,
114 		const struct usb_endpoint_descriptor *desc);
115 	int (*disable) (struct usb_ep *ep);
116 
117 	struct usb_request *(*alloc_request) (struct usb_ep *ep,
118 		gfp_t gfp_flags);
119 	void (*free_request) (struct usb_ep *ep, struct usb_request *req);
120 
121 	int (*queue) (struct usb_ep *ep, struct usb_request *req,
122 		gfp_t gfp_flags);
123 	int (*dequeue) (struct usb_ep *ep, struct usb_request *req);
124 
125 	int (*set_halt) (struct usb_ep *ep, int value);
126 	int (*set_wedge)(struct usb_ep *ep);
127 	int (*fifo_status) (struct usb_ep *ep);
128 	void (*fifo_flush) (struct usb_ep *ep);
129 };
130 
131 /**
132  * struct usb_ep - device side representation of USB endpoint
133  * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
134  * @ops: Function pointers used to access hardware-specific operations.
135  * @ep_list:the gadget's ep_list holds all of its endpoints
136  * @maxpacket:The maximum packet size used on this endpoint.  The initial
137  *	value can sometimes be reduced (hardware allowing), according to
138  *      the endpoint descriptor used to configure the endpoint.
139  * @maxpacket_limit:The maximum packet size value which can be handled by this
140  *	endpoint. It's set once by UDC driver when endpoint is initialized, and
141  *	should not be changed. Should not be confused with maxpacket.
142  * @max_streams: The maximum number of streams supported
143  * 	by this EP (0 - 16, actual number is 2^n)
144  * @maxburst: the maximum number of bursts supported by this EP (for usb3)
145  * @driver_data:for use by the gadget driver.  all other fields are
146  *	read-only to gadget drivers.
147  * @desc: endpoint descriptor.  This pointer is set before the endpoint is
148  * 	enabled and remains valid until the endpoint is disabled.
149  * @comp_desc: In case of SuperSpeed support, this is the endpoint companion
150  * 	descriptor that is used to configure the endpoint
151  *
152  * the bus controller driver lists all the general purpose endpoints in
153  * gadget->ep_list.  the control endpoint (gadget->ep0) is not in that list,
154  * and is accessed only in response to a driver setup() callback.
155  */
156 struct usb_ep {
157 	void			*driver_data;
158 	const char		*name;
159 	const struct usb_ep_ops	*ops;
160 	struct list_head	ep_list;
161 	unsigned		maxpacket:16;
162 	unsigned		maxpacket_limit:16;
163 	unsigned		max_streams:16;
164 	unsigned		maxburst:5;
165 	const struct usb_endpoint_descriptor	*desc;
166 	const struct usb_ss_ep_comp_descriptor	*comp_desc;
167 };
168 
169 /*-------------------------------------------------------------------------*/
170 
171 /**
172  * usb_ep_set_maxpacket_limit - set maximum packet size limit for endpoint
173  * @ep:the endpoint being configured
174  * @maxpacket_limit:value of maximum packet size limit
175  *
176  * This function shoud be used only in UDC drivers to initialize endpoint
177  * (usually in probe function).
178  */
usb_ep_set_maxpacket_limit(struct usb_ep * ep,unsigned maxpacket_limit)179 static inline void usb_ep_set_maxpacket_limit(struct usb_ep *ep,
180 					      unsigned maxpacket_limit)
181 {
182 	ep->maxpacket_limit = maxpacket_limit;
183 	ep->maxpacket = maxpacket_limit;
184 }
185 
186 /**
187  * usb_ep_enable - configure endpoint, making it usable
188  * @ep:the endpoint being configured.  may not be the endpoint named "ep0".
189  *	drivers discover endpoints through the ep_list of a usb_gadget.
190  * @desc:descriptor for desired behavior.  caller guarantees this pointer
191  *	remains valid until the endpoint is disabled; the data byte order
192  *	is little-endian (usb-standard).
193  *
194  * when configurations are set, or when interface settings change, the driver
195  * will enable or disable the relevant endpoints.  while it is enabled, an
196  * endpoint may be used for i/o until the driver receives a disconnect() from
197  * the host or until the endpoint is disabled.
198  *
199  * the ep0 implementation (which calls this routine) must ensure that the
200  * hardware capabilities of each endpoint match the descriptor provided
201  * for it.  for example, an endpoint named "ep2in-bulk" would be usable
202  * for interrupt transfers as well as bulk, but it likely couldn't be used
203  * for iso transfers or for endpoint 14.  some endpoints are fully
204  * configurable, with more generic names like "ep-a".  (remember that for
205  * USB, "in" means "towards the USB master".)
206  *
207  * returns zero, or a negative error code.
208  */
usb_ep_enable(struct usb_ep * ep,const struct usb_endpoint_descriptor * desc)209 static inline int usb_ep_enable(struct usb_ep *ep,
210 				const struct usb_endpoint_descriptor *desc)
211 {
212 	return ep->ops->enable(ep, desc);
213 }
214 
215 /**
216  * usb_ep_disable - endpoint is no longer usable
217  * @ep:the endpoint being unconfigured.  may not be the endpoint named "ep0".
218  *
219  * no other task may be using this endpoint when this is called.
220  * any pending and uncompleted requests will complete with status
221  * indicating disconnect (-ESHUTDOWN) before this call returns.
222  * gadget drivers must call usb_ep_enable() again before queueing
223  * requests to the endpoint.
224  *
225  * returns zero, or a negative error code.
226  */
usb_ep_disable(struct usb_ep * ep)227 static inline int usb_ep_disable(struct usb_ep *ep)
228 {
229 	return ep->ops->disable(ep);
230 }
231 
232 /**
233  * usb_ep_alloc_request - allocate a request object to use with this endpoint
234  * @ep:the endpoint to be used with with the request
235  * @gfp_flags:GFP_* flags to use
236  *
237  * Request objects must be allocated with this call, since they normally
238  * need controller-specific setup and may even need endpoint-specific
239  * resources such as allocation of DMA descriptors.
240  * Requests may be submitted with usb_ep_queue(), and receive a single
241  * completion callback.  Free requests with usb_ep_free_request(), when
242  * they are no longer needed.
243  *
244  * Returns the request, or null if one could not be allocated.
245  */
usb_ep_alloc_request(struct usb_ep * ep,gfp_t gfp_flags)246 static inline struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
247 						       gfp_t gfp_flags)
248 {
249 	return ep->ops->alloc_request(ep, gfp_flags);
250 }
251 
252 /**
253  * usb_ep_free_request - frees a request object
254  * @ep:the endpoint associated with the request
255  * @req:the request being freed
256  *
257  * Reverses the effect of usb_ep_alloc_request().
258  * Caller guarantees the request is not queued, and that it will
259  * no longer be requeued (or otherwise used).
260  */
usb_ep_free_request(struct usb_ep * ep,struct usb_request * req)261 static inline void usb_ep_free_request(struct usb_ep *ep,
262 				       struct usb_request *req)
263 {
264 	ep->ops->free_request(ep, req);
265 }
266 
267 /**
268  * usb_ep_queue - queues (submits) an I/O request to an endpoint.
269  * @ep:the endpoint associated with the request
270  * @req:the request being submitted
271  * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
272  *	pre-allocate all necessary memory with the request.
273  *
274  * This tells the device controller to perform the specified request through
275  * that endpoint (reading or writing a buffer).  When the request completes,
276  * including being canceled by usb_ep_dequeue(), the request's completion
277  * routine is called to return the request to the driver.  Any endpoint
278  * (except control endpoints like ep0) may have more than one transfer
279  * request queued; they complete in FIFO order.  Once a gadget driver
280  * submits a request, that request may not be examined or modified until it
281  * is given back to that driver through the completion callback.
282  *
283  * Each request is turned into one or more packets.  The controller driver
284  * never merges adjacent requests into the same packet.  OUT transfers
285  * will sometimes use data that's already buffered in the hardware.
286  * Drivers can rely on the fact that the first byte of the request's buffer
287  * always corresponds to the first byte of some USB packet, for both
288  * IN and OUT transfers.
289  *
290  * Bulk endpoints can queue any amount of data; the transfer is packetized
291  * automatically.  The last packet will be short if the request doesn't fill it
292  * out completely.  Zero length packets (ZLPs) should be avoided in portable
293  * protocols since not all usb hardware can successfully handle zero length
294  * packets.  (ZLPs may be explicitly written, and may be implicitly written if
295  * the request 'zero' flag is set.)  Bulk endpoints may also be used
296  * for interrupt transfers; but the reverse is not true, and some endpoints
297  * won't support every interrupt transfer.  (Such as 768 byte packets.)
298  *
299  * Interrupt-only endpoints are less functional than bulk endpoints, for
300  * example by not supporting queueing or not handling buffers that are
301  * larger than the endpoint's maxpacket size.  They may also treat data
302  * toggle differently.
303  *
304  * Control endpoints ... after getting a setup() callback, the driver queues
305  * one response (even if it would be zero length).  That enables the
306  * status ack, after transfering data as specified in the response.  Setup
307  * functions may return negative error codes to generate protocol stalls.
308  * (Note that some USB device controllers disallow protocol stall responses
309  * in some cases.)  When control responses are deferred (the response is
310  * written after the setup callback returns), then usb_ep_set_halt() may be
311  * used on ep0 to trigger 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  * report errors; errors will also be
319  * reported when the usb peripheral is disconnected.
320  */
usb_ep_queue(struct usb_ep * ep,struct usb_request * req,gfp_t gfp_flags)321 static inline int usb_ep_queue(struct usb_ep *ep,
322 			       struct usb_request *req, gfp_t 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  */
usb_ep_dequeue(struct usb_ep * ep,struct usb_request * req)341 static 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  * Note that while an endpoint CLEAR_FEATURE will be invisible to the
357  * gadget driver, a SET_INTERFACE will not be.  To reset endpoints for the
358  * current altsetting, see usb_ep_clear_halt().  When switching altsettings,
359  * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
360  *
361  * Returns zero, or a negative error code.  On success, this call sets
362  * underlying hardware state that blocks data transfers.
363  * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
364  * transfer requests are still queued, or if the controller hardware
365  * (usually a FIFO) still holds bytes that the host hasn't collected.
366  */
usb_ep_set_halt(struct usb_ep * ep)367 static inline int usb_ep_set_halt(struct usb_ep *ep)
368 {
369 	return ep->ops->set_halt(ep, 1);
370 }
371 
372 /**
373  * usb_ep_clear_halt - clears endpoint halt, and resets toggle
374  * @ep:the bulk or interrupt endpoint being reset
375  *
376  * Use this when responding to the standard usb "set interface" request,
377  * for endpoints that aren't reconfigured, after clearing any other state
378  * in the endpoint's i/o queue.
379  *
380  * Returns zero, or a negative error code.  On success, this call clears
381  * the underlying hardware state reflecting endpoint halt and data toggle.
382  * Note that some hardware can't support this request (like pxa2xx_udc),
383  * and accordingly can't correctly implement interface altsettings.
384  */
usb_ep_clear_halt(struct usb_ep * ep)385 static inline int usb_ep_clear_halt(struct usb_ep *ep)
386 {
387 	return ep->ops->set_halt(ep, 0);
388 }
389 
390 /**
391  * usb_ep_fifo_status - returns number of bytes in fifo, or error
392  * @ep: the endpoint whose fifo status is being checked.
393  *
394  * FIFO endpoints may have "unclaimed data" in them in certain cases,
395  * such as after aborted transfers.  Hosts may not have collected all
396  * the IN data written by the gadget driver (and reported by a request
397  * completion).  The gadget driver may not have collected all the data
398  * written OUT to it by the host.  Drivers that need precise handling for
399  * fault reporting or recovery may need to use this call.
400  *
401  * This returns the number of such bytes in the fifo, or a negative
402  * errno if the endpoint doesn't use a FIFO or doesn't support such
403  * precise handling.
404  */
usb_ep_fifo_status(struct usb_ep * ep)405 static inline int usb_ep_fifo_status(struct usb_ep *ep)
406 {
407 	if (ep->ops->fifo_status)
408 		return ep->ops->fifo_status(ep);
409 	else
410 		return -EOPNOTSUPP;
411 }
412 
413 /**
414  * usb_ep_fifo_flush - flushes contents of a fifo
415  * @ep: the endpoint whose fifo is being flushed.
416  *
417  * This call may be used to flush the "unclaimed data" that may exist in
418  * an endpoint fifo after abnormal transaction terminations.  The call
419  * must never be used except when endpoint is not being used for any
420  * protocol translation.
421  */
usb_ep_fifo_flush(struct usb_ep * ep)422 static inline void usb_ep_fifo_flush(struct usb_ep *ep)
423 {
424 	if (ep->ops->fifo_flush)
425 		ep->ops->fifo_flush(ep);
426 }
427 
428 
429 /*-------------------------------------------------------------------------*/
430 
431 struct usb_gadget;
432 struct usb_gadget_driver;
433 
434 /* the rest of the api to the controller hardware: device operations,
435  * which don't involve endpoints (or i/o).
436  */
437 struct usb_gadget_ops {
438 	int	(*get_frame)(struct usb_gadget *);
439 	int	(*wakeup)(struct usb_gadget *);
440 	int	(*set_selfpowered) (struct usb_gadget *, int is_selfpowered);
441 	int	(*vbus_session) (struct usb_gadget *, int is_active);
442 	int	(*vbus_draw) (struct usb_gadget *, unsigned mA);
443 	int	(*pullup) (struct usb_gadget *, int is_on);
444 	int	(*ioctl)(struct usb_gadget *,
445 				unsigned code, unsigned long param);
446 	int	(*udc_start)(struct usb_gadget *,
447 			     struct usb_gadget_driver *);
448 	int	(*udc_stop)(struct usb_gadget *);
449 };
450 
451 /**
452  * struct usb_gadget - represents a usb slave device
453  * @ops: Function pointers used to access hardware-specific operations.
454  * @ep0: Endpoint zero, used when reading or writing responses to
455  *	driver setup() requests
456  * @ep_list: List of other endpoints supported by the device.
457  * @speed: Speed of current connection to USB host.
458  * @max_speed: Maximal speed the UDC can handle.  UDC must support this
459  *      and all slower speeds.
460  * @is_dualspeed: true if the controller supports both high and full speed
461  *	operation.  If it does, the gadget driver must also support both.
462  * @is_otg: true if the USB device port uses a Mini-AB jack, so that the
463  *	gadget driver must provide a USB OTG descriptor.
464  * @is_a_peripheral: false unless is_otg, the "A" end of a USB cable
465  *	is in the Mini-AB jack, and HNP has been used to switch roles
466  *	so that the "A" device currently acts as A-Peripheral, not A-Host.
467  * @a_hnp_support: OTG device feature flag, indicating that the A-Host
468  *	supports HNP at this port.
469  * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host
470  *	only supports HNP on a different root port.
471  * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
472  *	enabled HNP support.
473  * @name: Identifies the controller hardware type.  Used in diagnostics
474  *	and sometimes configuration.
475  * @dev: Driver model state for this abstract device.
476  * @quirk_ep_out_aligned_size: epout requires buffer size to be aligned to
477  *	MaxPacketSize.
478  *
479  * Gadgets have a mostly-portable "gadget driver" implementing device
480  * functions, handling all usb configurations and interfaces.  Gadget
481  * drivers talk to hardware-specific code indirectly, through ops vectors.
482  * That insulates the gadget driver from hardware details, and packages
483  * the hardware endpoints through generic i/o queues.  The "usb_gadget"
484  * and "usb_ep" interfaces provide that insulation from the hardware.
485  *
486  * Except for the driver data, all fields in this structure are
487  * read-only to the gadget driver.  That driver data is part of the
488  * "driver model" infrastructure in 2.6 (and later) kernels, and for
489  * earlier systems is grouped in a similar structure that's not known
490  * to the rest of the kernel.
491  *
492  * Values of the three OTG device feature flags are updated before the
493  * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before
494  * driver suspend() calls.  They are valid only when is_otg, and when the
495  * device is acting as a B-Peripheral (so is_a_peripheral is false).
496  */
497 struct usb_gadget {
498 	/* readonly to gadget driver */
499 	const struct usb_gadget_ops	*ops;
500 	struct usb_ep			*ep0;
501 	struct list_head		ep_list;	/* of usb_ep */
502 	enum usb_device_speed		speed;
503 	enum usb_device_speed		max_speed;
504 	enum usb_device_state		state;
505 	unsigned			is_dualspeed:1;
506 	unsigned			is_otg:1;
507 	unsigned			is_a_peripheral:1;
508 	unsigned			b_hnp_enable:1;
509 	unsigned			a_hnp_support:1;
510 	unsigned			a_alt_hnp_support:1;
511 	const char			*name;
512 	struct device			dev;
513 	unsigned			quirk_ep_out_aligned_size:1;
514 };
515 
set_gadget_data(struct usb_gadget * gadget,void * data)516 static inline void set_gadget_data(struct usb_gadget *gadget, void *data)
517 {
518 	gadget->dev.driver_data = data;
519 }
520 
get_gadget_data(struct usb_gadget * gadget)521 static inline void *get_gadget_data(struct usb_gadget *gadget)
522 {
523 	return gadget->dev.driver_data;
524 }
525 
dev_to_usb_gadget(struct device * dev)526 static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
527 {
528 	return container_of(dev, struct usb_gadget, dev);
529 }
530 
531 /* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
532 #define gadget_for_each_ep(tmp, gadget) \
533 	list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
534 
535 
536 /**
537  * gadget_is_dualspeed - return true iff the hardware handles high speed
538  * @g: controller that might support both high and full speeds
539  */
gadget_is_dualspeed(struct usb_gadget * g)540 static inline int gadget_is_dualspeed(struct usb_gadget *g)
541 {
542 #ifdef CONFIG_USB_GADGET_DUALSPEED
543 	/* runtime test would check "g->is_dualspeed" ... that might be
544 	 * useful to work around hardware bugs, but is mostly pointless
545 	 */
546 	return 1;
547 #else
548 	return 0;
549 #endif
550 }
551 
552 /**
553  * gadget_is_otg - return true iff the hardware is OTG-ready
554  * @g: controller that might have a Mini-AB connector
555  *
556  * This is a runtime test, since kernels with a USB-OTG stack sometimes
557  * run on boards which only have a Mini-B (or Mini-A) connector.
558  */
gadget_is_otg(struct usb_gadget * g)559 static inline int gadget_is_otg(struct usb_gadget *g)
560 {
561 #ifdef CONFIG_USB_OTG
562 	return g->is_otg;
563 #else
564 	return 0;
565 #endif
566 }
567 
568 /**
569  * usb_gadget_frame_number - returns the current frame number
570  * @gadget: controller that reports the frame number
571  *
572  * Returns the usb frame number, normally eleven bits from a SOF packet,
573  * or negative errno if this device doesn't support this capability.
574  */
usb_gadget_frame_number(struct usb_gadget * gadget)575 static inline int usb_gadget_frame_number(struct usb_gadget *gadget)
576 {
577 	return gadget->ops->get_frame(gadget);
578 }
579 
580 /**
581  * usb_gadget_wakeup - tries to wake up the host connected to this gadget
582  * @gadget: controller used to wake up the host
583  *
584  * Returns zero on success, else negative error code if the hardware
585  * doesn't support such attempts, or its support has not been enabled
586  * by the usb host.  Drivers must return device descriptors that report
587  * their ability to support this, or hosts won't enable it.
588  *
589  * This may also try to use SRP to wake the host and start enumeration,
590  * even if OTG isn't otherwise in use.  OTG devices may also start
591  * remote wakeup even when hosts don't explicitly enable it.
592  */
usb_gadget_wakeup(struct usb_gadget * gadget)593 static inline int usb_gadget_wakeup(struct usb_gadget *gadget)
594 {
595 	if (!gadget->ops->wakeup)
596 		return -EOPNOTSUPP;
597 	return gadget->ops->wakeup(gadget);
598 }
599 
600 /**
601  * usb_gadget_set_selfpowered - sets the device selfpowered feature.
602  * @gadget:the device being declared as self-powered
603  *
604  * this affects the device status reported by the hardware driver
605  * to reflect that it now has a local power supply.
606  *
607  * returns zero on success, else negative errno.
608  */
usb_gadget_set_selfpowered(struct usb_gadget * gadget)609 static inline int usb_gadget_set_selfpowered(struct usb_gadget *gadget)
610 {
611 	if (!gadget->ops->set_selfpowered)
612 		return -EOPNOTSUPP;
613 	return gadget->ops->set_selfpowered(gadget, 1);
614 }
615 
616 /**
617  * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
618  * @gadget:the device being declared as bus-powered
619  *
620  * this affects the device status reported by the hardware driver.
621  * some hardware may not support bus-powered operation, in which
622  * case this feature's value can never change.
623  *
624  * returns zero on success, else negative errno.
625  */
usb_gadget_clear_selfpowered(struct usb_gadget * gadget)626 static inline int usb_gadget_clear_selfpowered(struct usb_gadget *gadget)
627 {
628 	if (!gadget->ops->set_selfpowered)
629 		return -EOPNOTSUPP;
630 	return gadget->ops->set_selfpowered(gadget, 0);
631 }
632 
633 /**
634  * usb_gadget_vbus_connect - Notify controller that VBUS is powered
635  * @gadget:The device which now has VBUS power.
636  *
637  * This call is used by a driver for an external transceiver (or GPIO)
638  * that detects a VBUS power session starting.  Common responses include
639  * resuming the controller, activating the D+ (or D-) pullup to let the
640  * host detect that a USB device is attached, and starting to draw power
641  * (8mA or possibly more, especially after SET_CONFIGURATION).
642  *
643  * Returns zero on success, else negative errno.
644  */
usb_gadget_vbus_connect(struct usb_gadget * gadget)645 static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget)
646 {
647 	if (!gadget->ops->vbus_session)
648 		return -EOPNOTSUPP;
649 	return gadget->ops->vbus_session(gadget, 1);
650 }
651 
652 /**
653  * usb_gadget_vbus_draw - constrain controller's VBUS power usage
654  * @gadget:The device whose VBUS usage is being described
655  * @mA:How much current to draw, in milliAmperes.  This should be twice
656  *	the value listed in the configuration descriptor bMaxPower field.
657  *
658  * This call is used by gadget drivers during SET_CONFIGURATION calls,
659  * reporting how much power the device may consume.  For example, this
660  * could affect how quickly batteries are recharged.
661  *
662  * Returns zero on success, else negative errno.
663  */
usb_gadget_vbus_draw(struct usb_gadget * gadget,unsigned mA)664 static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
665 {
666 	if (!gadget->ops->vbus_draw)
667 		return -EOPNOTSUPP;
668 	return gadget->ops->vbus_draw(gadget, mA);
669 }
670 
671 /**
672  * usb_gadget_vbus_disconnect - notify controller about VBUS session end
673  * @gadget:the device whose VBUS supply is being described
674  *
675  * This call is used by a driver for an external transceiver (or GPIO)
676  * that detects a VBUS power session ending.  Common responses include
677  * reversing everything done in usb_gadget_vbus_connect().
678  *
679  * Returns zero on success, else negative errno.
680  */
usb_gadget_vbus_disconnect(struct usb_gadget * gadget)681 static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
682 {
683 	if (!gadget->ops->vbus_session)
684 		return -EOPNOTSUPP;
685 	return gadget->ops->vbus_session(gadget, 0);
686 }
687 
688 /**
689  * usb_gadget_connect - software-controlled connect to USB host
690  * @gadget:the peripheral being connected
691  *
692  * Enables the D+ (or potentially D-) pullup.  The host will start
693  * enumerating this gadget when the pullup is active and a VBUS session
694  * is active (the link is powered).  This pullup is always enabled unless
695  * usb_gadget_disconnect() has been used to disable it.
696  *
697  * Returns zero on success, else negative errno.
698  */
usb_gadget_connect(struct usb_gadget * gadget)699 static inline int usb_gadget_connect(struct usb_gadget *gadget)
700 {
701 	if (!gadget->ops->pullup)
702 		return -EOPNOTSUPP;
703 	return gadget->ops->pullup(gadget, 1);
704 }
705 
706 /**
707  * usb_gadget_disconnect - software-controlled disconnect from USB host
708  * @gadget:the peripheral being disconnected
709  *
710  * Disables the D+ (or potentially D-) pullup, which the host may see
711  * as a disconnect (when a VBUS session is active).  Not all systems
712  * support software pullup controls.
713  *
714  * This routine may be used during the gadget driver bind() call to prevent
715  * the peripheral from ever being visible to the USB host, unless later
716  * usb_gadget_connect() is called.  For example, user mode components may
717  * need to be activated before the system can talk to hosts.
718  *
719  * Returns zero on success, else negative errno.
720  */
usb_gadget_disconnect(struct usb_gadget * gadget)721 static inline int usb_gadget_disconnect(struct usb_gadget *gadget)
722 {
723 	if (!gadget->ops->pullup)
724 		return -EOPNOTSUPP;
725 	return gadget->ops->pullup(gadget, 0);
726 }
727 
728 
729 /*-------------------------------------------------------------------------*/
730 
731 /**
732  * struct usb_gadget_driver - driver for usb 'slave' devices
733  * @function: String describing the gadget's function
734  * @speed: Highest speed the driver handles.
735  * @bind: Invoked when the driver is bound to a gadget, usually
736  *	after registering the driver.
737  *	At that point, ep0 is fully initialized, and ep_list holds
738  *	the currently-available endpoints.
739  *	Called in a context that permits sleeping.
740  * @setup: Invoked for ep0 control requests that aren't handled by
741  *	the hardware level driver. Most calls must be handled by
742  *	the gadget driver, including descriptor and configuration
743  *	management.  The 16 bit members of the setup data are in
744  *	USB byte order. Called in_interrupt; this may not sleep.  Driver
745  *	queues a response to ep0, or returns negative to stall.
746  * @disconnect: Invoked after all transfers have been stopped,
747  *	when the host is disconnected.  May be called in_interrupt; this
748  *	may not sleep.  Some devices can't detect disconnect, so this might
749  *	not be called except as part of controller shutdown.
750  * @unbind: Invoked when the driver is unbound from a gadget,
751  *	usually from rmmod (after a disconnect is reported).
752  *	Called in a context that permits sleeping.
753  * @suspend: Invoked on USB suspend.  May be called in_interrupt.
754  * @resume: Invoked on USB resume.  May be called in_interrupt.
755  * @reset: Invoked on USB bus reset. It is mandatory for all gadget drivers
756  *	and should be called in_interrupt.
757  *
758  * Devices are disabled till a gadget driver successfully bind()s, which
759  * means the driver will handle setup() requests needed to enumerate (and
760  * meet "chapter 9" requirements) then do some useful work.
761  *
762  * If gadget->is_otg is true, the gadget driver must provide an OTG
763  * descriptor during enumeration, or else fail the bind() call.  In such
764  * cases, no USB traffic may flow until both bind() returns without
765  * having called usb_gadget_disconnect(), and the USB host stack has
766  * initialized.
767  *
768  * Drivers use hardware-specific knowledge to configure the usb hardware.
769  * endpoint addressing is only one of several hardware characteristics that
770  * are in descriptors the ep0 implementation returns from setup() calls.
771  *
772  * Except for ep0 implementation, most driver code shouldn't need change to
773  * run on top of different usb controllers.  It'll use endpoints set up by
774  * that ep0 implementation.
775  *
776  * The usb controller driver handles a few standard usb requests.  Those
777  * include set_address, and feature flags for devices, interfaces, and
778  * endpoints (the get_status, set_feature, and clear_feature requests).
779  *
780  * Accordingly, the driver's setup() callback must always implement all
781  * get_descriptor requests, returning at least a device descriptor and
782  * a configuration descriptor.  Drivers must make sure the endpoint
783  * descriptors match any hardware constraints. Some hardware also constrains
784  * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
785  *
786  * The driver's setup() callback must also implement set_configuration,
787  * and should also implement set_interface, get_configuration, and
788  * get_interface.  Setting a configuration (or interface) is where
789  * endpoints should be activated or (config 0) shut down.
790  *
791  * (Note that only the default control endpoint is supported.  Neither
792  * hosts nor devices generally support control traffic except to ep0.)
793  *
794  * Most devices will ignore USB suspend/resume operations, and so will
795  * not provide those callbacks.  However, some may need to change modes
796  * when the host is not longer directing those activities.  For example,
797  * local controls (buttons, dials, etc) may need to be re-enabled since
798  * the (remote) host can't do that any longer; or an error state might
799  * be cleared, to make the device behave identically whether or not
800  * power is maintained.
801  */
802 struct usb_gadget_driver {
803 	char			*function;
804 	enum usb_device_speed	speed;
805 	int			(*bind)(struct usb_gadget *);
806 	void			(*unbind)(struct usb_gadget *);
807 	int			(*setup)(struct usb_gadget *,
808 					const struct usb_ctrlrequest *);
809 	void			(*disconnect)(struct usb_gadget *);
810 	void			(*suspend)(struct usb_gadget *);
811 	void			(*resume)(struct usb_gadget *);
812 	void			(*reset)(struct usb_gadget *);
813 };
814 
815 
816 /*-------------------------------------------------------------------------*/
817 
818 /* driver modules register and unregister, as usual.
819  * these calls must be made in a context that can sleep.
820  *
821  * these will usually be implemented directly by the hardware-dependent
822  * usb bus interface driver, which will only support a single driver.
823  */
824 
825 /**
826  * usb_gadget_register_driver - register a gadget driver
827  * @driver:the driver being registered
828  *
829  * Call this in your gadget driver's module initialization function,
830  * to tell the underlying usb controller driver about your driver.
831  * The driver's bind() function will be called to bind it to a
832  * gadget before this registration call returns.  It's expected that
833  * the bind() functions will be in init sections.
834  * This function must be called in a context that can sleep.
835  */
836 int usb_gadget_register_driver(struct usb_gadget_driver *driver);
837 
838 /**
839  * usb_gadget_unregister_driver - unregister a gadget driver
840  * @driver:the driver being unregistered
841  *
842  * Call this in your gadget driver's module cleanup function,
843  * to tell the underlying usb controller that your driver is
844  * going away.  If the controller is connected to a USB host,
845  * it will first disconnect().  The driver is also requested
846  * to unbind() and clean up any device state, before this procedure
847  * finally returns.  It's expected that the unbind() functions
848  * will in in exit sections, so may not be linked in some kernels.
849  * This function must be called in a context that can sleep.
850  */
851 int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);
852 
853 int usb_add_gadget_udc_release(struct device *parent,
854 		struct usb_gadget *gadget, void (*release)(struct device *dev));
855 int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget);
856 void usb_del_gadget_udc(struct usb_gadget *gadget);
857 /*-------------------------------------------------------------------------*/
858 
859 /* utility to simplify dealing with string descriptors */
860 
861 /**
862  * struct usb_gadget_strings - a set of USB strings in a given language
863  * @language:identifies the strings' language (0x0409 for en-us)
864  * @strings:array of strings with their ids
865  *
866  * If you're using usb_gadget_get_string(), use this to wrap all the
867  * strings for a given language.
868  */
869 struct usb_gadget_strings {
870 	u16			language;	/* 0x0409 for en-us */
871 	struct usb_string	*strings;
872 };
873 
874 /* put descriptor for string with that id into buf (buflen >= 256) */
875 int usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf);
876 
877 /*-------------------------------------------------------------------------*/
878 
879 /* utility to simplify managing config descriptors */
880 
881 /* write vector of descriptors into buffer */
882 int usb_descriptor_fillbuf(void *, unsigned,
883 		const struct usb_descriptor_header **);
884 
885 /* build config descriptor from single descriptor vector */
886 int usb_gadget_config_buf(const struct usb_config_descriptor *config,
887 	void *buf, unsigned buflen, const struct usb_descriptor_header **desc);
888 
889 /*-------------------------------------------------------------------------*/
890 /* utility to simplify map/unmap of usb_requests to/from DMA */
891 
892 extern int usb_gadget_map_request(struct usb_gadget *gadget,
893 				  struct usb_request *req, int is_in);
894 
895 extern void usb_gadget_unmap_request(struct usb_gadget *gadget,
896 				     struct usb_request *req, int is_in);
897 
898 /*-------------------------------------------------------------------------*/
899 
900 /* utility to set gadget state properly */
901 
902 extern void usb_gadget_set_state(struct usb_gadget *gadget,
903 				 enum usb_device_state state);
904 
905 /*-------------------------------------------------------------------------*/
906 
907 /* utility to tell udc core that the bus reset occurs */
908 extern void usb_gadget_udc_reset(struct usb_gadget *gadget,
909 				 struct usb_gadget_driver *driver);
910 
911 /*-------------------------------------------------------------------------*/
912 
913 /* utility to give requests back to the gadget layer */
914 
915 extern void usb_gadget_giveback_request(struct usb_ep *ep,
916 					struct usb_request *req);
917 
918 /*-------------------------------------------------------------------------*/
919 
920 /* utility wrapping a simple endpoint selection policy */
921 
922 extern struct usb_ep *usb_ep_autoconfig(struct usb_gadget *,
923 			struct usb_endpoint_descriptor *);
924 
925 extern void usb_ep_autoconfig_reset(struct usb_gadget *);
926 
927 extern int usb_gadget_handle_interrupts(int index);
928 
929 #endif	/* __LINUX_USB_GADGET_H */
930