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 
15 #ifndef __LINUX_USB_GADGET_H
16 #define __LINUX_USB_GADGET_H
17 
18 #include <linux/device.h>
19 #include <linux/errno.h>
20 #include <linux/init.h>
21 #include <linux/list.h>
22 #include <linux/slab.h>
23 #include <linux/scatterlist.h>
24 #include <linux/types.h>
25 #include <linux/usb/ch9.h>
26 
27 struct usb_ep;
28 
29 /**
30  * struct usb_request - describes one i/o request
31  * @buf: Buffer used for data.  Always provide this; some controllers
32  *	only use PIO, or don't use DMA for some endpoints.
33  * @dma: DMA address corresponding to 'buf'.  If you don't set this
34  *	field, and the usb controller needs one, it is responsible
35  *	for mapping and unmapping the buffer.
36  * @sg: a scatterlist for SG-capable controllers.
37  * @num_sgs: number of SG entries
38  * @num_mapped_sgs: number of SG entries mapped to DMA (internal)
39  * @length: Length of that data
40  * @stream_id: The stream id, when USB3.0 bulk streams are being used
41  * @no_interrupt: If true, hints that no completion irq is needed.
42  *	Helpful sometimes with deep request queues that are handled
43  *	directly by DMA controllers.
44  * @zero: If true, when writing data, makes the last packet be "short"
45  *     by adding a zero length packet as needed;
46  * @short_not_ok: When reading data, makes short packets be
47  *     treated as errors (queue stops advancing till cleanup).
48  * @complete: Function called when request completes, so this request and
49  *	its buffer may be re-used.  The function will always be called with
50  *	interrupts disabled, and it must not sleep.
51  *	Reads terminate with a short packet, or when the buffer fills,
52  *	whichever comes first.  When writes terminate, some data bytes
53  *	will usually still be in flight (often in a hardware fifo).
54  *	Errors (for reads or writes) stop the queue from advancing
55  *	until the completion function returns, so that any transfers
56  *	invalidated by the error may first be dequeued.
57  * @context: For use by the completion callback
58  * @list: For use by the gadget driver.
59  * @status: Reports completion code, zero or a negative errno.
60  *	Normally, faults block the transfer queue from advancing until
61  *	the completion callback returns.
62  *	Code "-ESHUTDOWN" indicates completion caused by device disconnect,
63  *	or when the driver disabled the endpoint.
64  * @actual: Reports bytes transferred to/from the buffer.  For reads (OUT
65  *	transfers) this may be less than the requested length.  If the
66  *	short_not_ok flag is set, short reads are treated as errors
67  *	even when status otherwise indicates successful completion.
68  *	Note that for writes (IN transfers) some data bytes may still
69  *	reside in a device-side FIFO when the request is reported as
70  *	complete.
71  *
72  * These are allocated/freed through the endpoint they're used with.  The
73  * hardware's driver can add extra per-request data to the memory it returns,
74  * which often avoids separate memory allocations (potential failures),
75  * later when the request is queued.
76  *
77  * Request flags affect request handling, such as whether a zero length
78  * packet is written (the "zero" flag), whether a short read should be
79  * treated as an error (blocking request queue advance, the "short_not_ok"
80  * flag), or hinting that an interrupt is not required (the "no_interrupt"
81  * flag, for use with deep request queues).
82  *
83  * Bulk endpoints can use any size buffers, and can also be used for interrupt
84  * transfers. interrupt-only endpoints can be much less functional.
85  *
86  * NOTE:  this is analogous to 'struct urb' on the host side, except that
87  * it's thinner and promotes more pre-allocation.
88  */
89 
90 struct usb_request {
91 	void			*buf;
92 	unsigned		length;
93 	dma_addr_t		dma;
94 
95 	struct scatterlist	*sg;
96 	unsigned		num_sgs;
97 	unsigned		num_mapped_sgs;
98 
99 	unsigned		stream_id:16;
100 	unsigned		no_interrupt:1;
101 	unsigned		zero:1;
102 	unsigned		short_not_ok:1;
103 
104 	void			(*complete)(struct usb_ep *ep,
105 					struct usb_request *req);
106 	void			*context;
107 	struct list_head	list;
108 
109 	int			status;
110 	unsigned		actual;
111 };
112 
113 /*-------------------------------------------------------------------------*/
114 
115 /* endpoint-specific parts of the api to the usb controller hardware.
116  * unlike the urb model, (de)multiplexing layers are not required.
117  * (so this api could slash overhead if used on the host side...)
118  *
119  * note that device side usb controllers commonly differ in how many
120  * endpoints they support, as well as their capabilities.
121  */
122 struct usb_ep_ops {
123 	int (*enable) (struct usb_ep *ep,
124 		const struct usb_endpoint_descriptor *desc);
125 	int (*disable) (struct usb_ep *ep);
126 
127 	struct usb_request *(*alloc_request) (struct usb_ep *ep,
128 		gfp_t gfp_flags);
129 	void (*free_request) (struct usb_ep *ep, struct usb_request *req);
130 
131 	int (*queue) (struct usb_ep *ep, struct usb_request *req,
132 		gfp_t gfp_flags);
133 	int (*dequeue) (struct usb_ep *ep, struct usb_request *req);
134 
135 	int (*set_halt) (struct usb_ep *ep, int value);
136 	int (*set_wedge) (struct usb_ep *ep);
137 
138 	int (*fifo_status) (struct usb_ep *ep);
139 	void (*fifo_flush) (struct usb_ep *ep);
140 };
141 
142 /**
143  * struct usb_ep - device side representation of USB endpoint
144  * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
145  * @ops: Function pointers used to access hardware-specific operations.
146  * @ep_list:the gadget's ep_list holds all of its endpoints
147  * @maxpacket:The maximum packet size used on this endpoint.  The initial
148  *	value can sometimes be reduced (hardware allowing), according to
149  *      the endpoint descriptor used to configure the endpoint.
150  * @max_streams: The maximum number of streams supported
151  *	by this EP (0 - 16, actual number is 2^n)
152  * @mult: multiplier, 'mult' value for SS Isoc EPs
153  * @maxburst: the maximum number of bursts supported by this EP (for usb3)
154  * @driver_data:for use by the gadget driver.
155  * @address: used to identify the endpoint when finding descriptor that
156  *	matches connection speed
157  * @desc: endpoint descriptor.  This pointer is set before the endpoint is
158  *	enabled and remains valid until the endpoint is disabled.
159  * @comp_desc: In case of SuperSpeed support, this is the endpoint companion
160  *	descriptor that is used to configure the endpoint
161  *
162  * the bus controller driver lists all the general purpose endpoints in
163  * gadget->ep_list.  the control endpoint (gadget->ep0) is not in that list,
164  * and is accessed only in response to a driver setup() callback.
165  */
166 struct usb_ep {
167 	void			*driver_data;
168 
169 	const char		*name;
170 	const struct usb_ep_ops	*ops;
171 	struct list_head	ep_list;
172 	unsigned		maxpacket:16;
173 	unsigned		max_streams:16;
174 	unsigned		mult:2;
175 	unsigned		maxburst:5;
176 	u8			address;
177 	const struct usb_endpoint_descriptor	*desc;
178 	const struct usb_ss_ep_comp_descriptor	*comp_desc;
179 };
180 
181 /*-------------------------------------------------------------------------*/
182 
183 /**
184  * usb_ep_enable - configure endpoint, making it usable
185  * @ep:the endpoint being configured.  may not be the endpoint named "ep0".
186  *	drivers discover endpoints through the ep_list of a usb_gadget.
187  *
188  * When configurations are set, or when interface settings change, the driver
189  * will enable or disable the relevant endpoints.  while it is enabled, an
190  * endpoint may be used for i/o until the driver receives a disconnect() from
191  * the host or until the endpoint is disabled.
192  *
193  * the ep0 implementation (which calls this routine) must ensure that the
194  * hardware capabilities of each endpoint match the descriptor provided
195  * for it.  for example, an endpoint named "ep2in-bulk" would be usable
196  * for interrupt transfers as well as bulk, but it likely couldn't be used
197  * for iso transfers or for endpoint 14.  some endpoints are fully
198  * configurable, with more generic names like "ep-a".  (remember that for
199  * USB, "in" means "towards the USB master".)
200  *
201  * returns zero, or a negative error code.
202  */
usb_ep_enable(struct usb_ep * ep)203 static inline int usb_ep_enable(struct usb_ep *ep)
204 {
205 	return ep->ops->enable(ep, ep->desc);
206 }
207 
208 /**
209  * usb_ep_disable - endpoint is no longer usable
210  * @ep:the endpoint being unconfigured.  may not be the endpoint named "ep0".
211  *
212  * no other task may be using this endpoint when this is called.
213  * any pending and uncompleted requests will complete with status
214  * indicating disconnect (-ESHUTDOWN) before this call returns.
215  * gadget drivers must call usb_ep_enable() again before queueing
216  * requests to the endpoint.
217  *
218  * returns zero, or a negative error code.
219  */
usb_ep_disable(struct usb_ep * ep)220 static inline int usb_ep_disable(struct usb_ep *ep)
221 {
222 	return ep->ops->disable(ep);
223 }
224 
225 /**
226  * usb_ep_alloc_request - allocate a request object to use with this endpoint
227  * @ep:the endpoint to be used with with the request
228  * @gfp_flags:GFP_* flags to use
229  *
230  * Request objects must be allocated with this call, since they normally
231  * need controller-specific setup and may even need endpoint-specific
232  * resources such as allocation of DMA descriptors.
233  * Requests may be submitted with usb_ep_queue(), and receive a single
234  * completion callback.  Free requests with usb_ep_free_request(), when
235  * they are no longer needed.
236  *
237  * Returns the request, or null if one could not be allocated.
238  */
usb_ep_alloc_request(struct usb_ep * ep,gfp_t gfp_flags)239 static inline struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
240 						       gfp_t gfp_flags)
241 {
242 	return ep->ops->alloc_request(ep, gfp_flags);
243 }
244 
245 /**
246  * usb_ep_free_request - frees a request object
247  * @ep:the endpoint associated with the request
248  * @req:the request being freed
249  *
250  * Reverses the effect of usb_ep_alloc_request().
251  * Caller guarantees the request is not queued, and that it will
252  * no longer be requeued (or otherwise used).
253  */
usb_ep_free_request(struct usb_ep * ep,struct usb_request * req)254 static inline void usb_ep_free_request(struct usb_ep *ep,
255 				       struct usb_request *req)
256 {
257 	ep->ops->free_request(ep, req);
258 }
259 
260 /**
261  * usb_ep_queue - queues (submits) an I/O request to an endpoint.
262  * @ep:the endpoint associated with the request
263  * @req:the request being submitted
264  * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
265  *	pre-allocate all necessary memory with the request.
266  *
267  * This tells the device controller to perform the specified request through
268  * that endpoint (reading or writing a buffer).  When the request completes,
269  * including being canceled by usb_ep_dequeue(), the request's completion
270  * routine is called to return the request to the driver.  Any endpoint
271  * (except control endpoints like ep0) may have more than one transfer
272  * request queued; they complete in FIFO order.  Once a gadget driver
273  * submits a request, that request may not be examined or modified until it
274  * is given back to that driver through the completion callback.
275  *
276  * Each request is turned into one or more packets.  The controller driver
277  * never merges adjacent requests into the same packet.  OUT transfers
278  * will sometimes use data that's already buffered in the hardware.
279  * Drivers can rely on the fact that the first byte of the request's buffer
280  * always corresponds to the first byte of some USB packet, for both
281  * IN and OUT transfers.
282  *
283  * Bulk endpoints can queue any amount of data; the transfer is packetized
284  * automatically.  The last packet will be short if the request doesn't fill it
285  * out completely.  Zero length packets (ZLPs) should be avoided in portable
286  * protocols since not all usb hardware can successfully handle zero length
287  * packets.  (ZLPs may be explicitly written, and may be implicitly written if
288  * the request 'zero' flag is set.)  Bulk endpoints may also be used
289  * for interrupt transfers; but the reverse is not true, and some endpoints
290  * won't support every interrupt transfer.  (Such as 768 byte packets.)
291  *
292  * Interrupt-only endpoints are less functional than bulk endpoints, for
293  * example by not supporting queueing or not handling buffers that are
294  * larger than the endpoint's maxpacket size.  They may also treat data
295  * toggle differently.
296  *
297  * Control endpoints ... after getting a setup() callback, the driver queues
298  * one response (even if it would be zero length).  That enables the
299  * status ack, after transferring data as specified in the response.  Setup
300  * functions may return negative error codes to generate protocol stalls.
301  * (Note that some USB device controllers disallow protocol stall responses
302  * in some cases.)  When control responses are deferred (the response is
303  * written after the setup callback returns), then usb_ep_set_halt() may be
304  * used on ep0 to trigger protocol stalls.  Depending on the controller,
305  * it may not be possible to trigger a status-stage protocol stall when the
306  * data stage is over, that is, from within the response's completion
307  * routine.
308  *
309  * For periodic endpoints, like interrupt or isochronous ones, the usb host
310  * arranges to poll once per interval, and the gadget driver usually will
311  * have queued some data to transfer at that time.
312  *
313  * Returns zero, or a negative error code.  Endpoints that are not enabled
314  * report errors; errors will also be
315  * reported when the usb peripheral is disconnected.
316  */
usb_ep_queue(struct usb_ep * ep,struct usb_request * req,gfp_t gfp_flags)317 static inline int usb_ep_queue(struct usb_ep *ep,
318 			       struct usb_request *req, gfp_t gfp_flags)
319 {
320 	return ep->ops->queue(ep, req, gfp_flags);
321 }
322 
323 /**
324  * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
325  * @ep:the endpoint associated with the request
326  * @req:the request being canceled
327  *
328  * if the request is still active on the endpoint, it is dequeued and its
329  * completion routine is called (with status -ECONNRESET); else a negative
330  * error code is returned.
331  *
332  * note that some hardware can't clear out write fifos (to unlink the request
333  * at the head of the queue) except as part of disconnecting from usb.  such
334  * restrictions prevent drivers from supporting configuration changes,
335  * even to configuration zero (a "chapter 9" requirement).
336  */
usb_ep_dequeue(struct usb_ep * ep,struct usb_request * req)337 static inline int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
338 {
339 	return ep->ops->dequeue(ep, req);
340 }
341 
342 /**
343  * usb_ep_set_halt - sets the endpoint halt feature.
344  * @ep: the non-isochronous endpoint being stalled
345  *
346  * Use this to stall an endpoint, perhaps as an error report.
347  * Except for control endpoints,
348  * the endpoint stays halted (will not stream any data) until the host
349  * clears this feature; drivers may need to empty the endpoint's request
350  * queue first, to make sure no inappropriate transfers happen.
351  *
352  * Note that while an endpoint CLEAR_FEATURE will be invisible to the
353  * gadget driver, a SET_INTERFACE will not be.  To reset endpoints for the
354  * current altsetting, see usb_ep_clear_halt().  When switching altsettings,
355  * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
356  *
357  * Returns zero, or a negative error code.  On success, this call sets
358  * underlying hardware state that blocks data transfers.
359  * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
360  * transfer requests are still queued, or if the controller hardware
361  * (usually a FIFO) still holds bytes that the host hasn't collected.
362  */
usb_ep_set_halt(struct usb_ep * ep)363 static inline int usb_ep_set_halt(struct usb_ep *ep)
364 {
365 	return ep->ops->set_halt(ep, 1);
366 }
367 
368 /**
369  * usb_ep_clear_halt - clears endpoint halt, and resets toggle
370  * @ep:the bulk or interrupt endpoint being reset
371  *
372  * Use this when responding to the standard usb "set interface" request,
373  * for endpoints that aren't reconfigured, after clearing any other state
374  * in the endpoint's i/o queue.
375  *
376  * Returns zero, or a negative error code.  On success, this call clears
377  * the underlying hardware state reflecting endpoint halt and data toggle.
378  * Note that some hardware can't support this request (like pxa2xx_udc),
379  * and accordingly can't correctly implement interface altsettings.
380  */
usb_ep_clear_halt(struct usb_ep * ep)381 static inline int usb_ep_clear_halt(struct usb_ep *ep)
382 {
383 	return ep->ops->set_halt(ep, 0);
384 }
385 
386 /**
387  * usb_ep_set_wedge - sets the halt feature and ignores clear requests
388  * @ep: the endpoint being wedged
389  *
390  * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT)
391  * requests. If the gadget driver clears the halt status, it will
392  * automatically unwedge the endpoint.
393  *
394  * Returns zero on success, else negative errno.
395  */
396 static inline int
usb_ep_set_wedge(struct usb_ep * ep)397 usb_ep_set_wedge(struct usb_ep *ep)
398 {
399 	if (ep->ops->set_wedge)
400 		return ep->ops->set_wedge(ep);
401 	else
402 		return ep->ops->set_halt(ep, 1);
403 }
404 
405 /**
406  * usb_ep_fifo_status - returns number of bytes in fifo, or error
407  * @ep: the endpoint whose fifo status is being checked.
408  *
409  * FIFO endpoints may have "unclaimed data" in them in certain cases,
410  * such as after aborted transfers.  Hosts may not have collected all
411  * the IN data written by the gadget driver (and reported by a request
412  * completion).  The gadget driver may not have collected all the data
413  * written OUT to it by the host.  Drivers that need precise handling for
414  * fault reporting or recovery may need to use this call.
415  *
416  * This returns the number of such bytes in the fifo, or a negative
417  * errno if the endpoint doesn't use a FIFO or doesn't support such
418  * precise handling.
419  */
usb_ep_fifo_status(struct usb_ep * ep)420 static inline int usb_ep_fifo_status(struct usb_ep *ep)
421 {
422 	if (ep->ops->fifo_status)
423 		return ep->ops->fifo_status(ep);
424 	else
425 		return -EOPNOTSUPP;
426 }
427 
428 /**
429  * usb_ep_fifo_flush - flushes contents of a fifo
430  * @ep: the endpoint whose fifo is being flushed.
431  *
432  * This call may be used to flush the "unclaimed data" that may exist in
433  * an endpoint fifo after abnormal transaction terminations.  The call
434  * must never be used except when endpoint is not being used for any
435  * protocol translation.
436  */
usb_ep_fifo_flush(struct usb_ep * ep)437 static inline void usb_ep_fifo_flush(struct usb_ep *ep)
438 {
439 	if (ep->ops->fifo_flush)
440 		ep->ops->fifo_flush(ep);
441 }
442 
443 
444 /*-------------------------------------------------------------------------*/
445 
446 struct usb_dcd_config_params {
447 	__u8  bU1devExitLat;	/* U1 Device exit Latency */
448 #define USB_DEFAULT_U1_DEV_EXIT_LAT	0x01	/* Less then 1 microsec */
449 	__le16 bU2DevExitLat;	/* U2 Device exit Latency */
450 #define USB_DEFAULT_U2_DEV_EXIT_LAT	0x1F4	/* Less then 500 microsec */
451 };
452 
453 
454 struct usb_gadget;
455 struct usb_gadget_driver;
456 
457 /* the rest of the api to the controller hardware: device operations,
458  * which don't involve endpoints (or i/o).
459  */
460 struct usb_gadget_ops {
461 	int	(*get_frame)(struct usb_gadget *);
462 	int	(*wakeup)(struct usb_gadget *);
463 	int	(*set_selfpowered) (struct usb_gadget *, int is_selfpowered);
464 	int	(*vbus_session) (struct usb_gadget *, int is_active);
465 	int	(*vbus_draw) (struct usb_gadget *, unsigned mA);
466 	int	(*pullup) (struct usb_gadget *, int is_on);
467 	int	(*ioctl)(struct usb_gadget *,
468 				unsigned code, unsigned long param);
469 	void	(*get_config_params)(struct usb_dcd_config_params *);
470 	int	(*udc_start)(struct usb_gadget *,
471 			struct usb_gadget_driver *);
472 	int	(*udc_stop)(struct usb_gadget *,
473 			struct usb_gadget_driver *);
474 
475 	/* Those two are deprecated */
476 	int	(*start)(struct usb_gadget_driver *,
477 			int (*bind)(struct usb_gadget *));
478 	int	(*stop)(struct usb_gadget_driver *);
479 };
480 
481 /**
482  * struct usb_gadget - represents a usb slave device
483  * @ops: Function pointers used to access hardware-specific operations.
484  * @ep0: Endpoint zero, used when reading or writing responses to
485  *	driver setup() requests
486  * @ep_list: List of other endpoints supported by the device.
487  * @speed: Speed of current connection to USB host.
488  * @max_speed: Maximal speed the UDC can handle.  UDC must support this
489  *      and all slower speeds.
490  * @sg_supported: true if we can handle scatter-gather
491  * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
492  *	gadget driver must provide a USB OTG descriptor.
493  * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable
494  *	is in the Mini-AB jack, and HNP has been used to switch roles
495  *	so that the "A" device currently acts as A-Peripheral, not A-Host.
496  * @a_hnp_support: OTG device feature flag, indicating that the A-Host
497  *	supports HNP at this port.
498  * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host
499  *	only supports HNP on a different root port.
500  * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
501  *	enabled HNP support.
502  * @name: Identifies the controller hardware type.  Used in diagnostics
503  *	and sometimes configuration.
504  * @dev: Driver model state for this abstract device.
505  *
506  * Gadgets have a mostly-portable "gadget driver" implementing device
507  * functions, handling all usb configurations and interfaces.  Gadget
508  * drivers talk to hardware-specific code indirectly, through ops vectors.
509  * That insulates the gadget driver from hardware details, and packages
510  * the hardware endpoints through generic i/o queues.  The "usb_gadget"
511  * and "usb_ep" interfaces provide that insulation from the hardware.
512  *
513  * Except for the driver data, all fields in this structure are
514  * read-only to the gadget driver.  That driver data is part of the
515  * "driver model" infrastructure in 2.6 (and later) kernels, and for
516  * earlier systems is grouped in a similar structure that's not known
517  * to the rest of the kernel.
518  *
519  * Values of the three OTG device feature flags are updated before the
520  * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before
521  * driver suspend() calls.  They are valid only when is_otg, and when the
522  * device is acting as a B-Peripheral (so is_a_peripheral is false).
523  */
524 struct usb_gadget {
525 	/* readonly to gadget driver */
526 	const struct usb_gadget_ops	*ops;
527 	struct usb_ep			*ep0;
528 	struct list_head		ep_list;	/* of usb_ep */
529 	enum usb_device_speed		speed;
530 	enum usb_device_speed		max_speed;
531 	unsigned			sg_supported:1;
532 	unsigned			is_otg:1;
533 	unsigned			is_a_peripheral:1;
534 	unsigned			b_hnp_enable:1;
535 	unsigned			a_hnp_support:1;
536 	unsigned			a_alt_hnp_support:1;
537 	const char			*name;
538 	struct device			dev;
539 };
540 
set_gadget_data(struct usb_gadget * gadget,void * data)541 static inline void set_gadget_data(struct usb_gadget *gadget, void *data)
542 	{ dev_set_drvdata(&gadget->dev, data); }
get_gadget_data(struct usb_gadget * gadget)543 static inline void *get_gadget_data(struct usb_gadget *gadget)
544 	{ return dev_get_drvdata(&gadget->dev); }
dev_to_usb_gadget(struct device * dev)545 static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
546 {
547 	return container_of(dev, struct usb_gadget, dev);
548 }
549 
550 /* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
551 #define gadget_for_each_ep(tmp, gadget) \
552 	list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
553 
554 
555 /**
556  * gadget_is_dualspeed - return true iff the hardware handles high speed
557  * @g: controller that might support both high and full speeds
558  */
gadget_is_dualspeed(struct usb_gadget * g)559 static inline int gadget_is_dualspeed(struct usb_gadget *g)
560 {
561 #ifdef CONFIG_USB_GADGET_DUALSPEED
562 	/* runtime test would check "g->max_speed" ... that might be
563 	 * useful to work around hardware bugs, but is mostly pointless
564 	 */
565 	return 1;
566 #else
567 	return 0;
568 #endif
569 }
570 
571 /**
572  * gadget_is_superspeed() - return true if the hardware handles
573  * supperspeed
574  * @g: controller that might support supper speed
575  */
gadget_is_superspeed(struct usb_gadget * g)576 static inline int gadget_is_superspeed(struct usb_gadget *g)
577 {
578 #ifdef CONFIG_USB_GADGET_SUPERSPEED
579 	/*
580 	 * runtime test would check "g->max_speed" ... that might be
581 	 * useful to work around hardware bugs, but is mostly pointless
582 	 */
583 	return 1;
584 #else
585 	return 0;
586 #endif
587 }
588 
589 /**
590  * gadget_is_otg - return true iff the hardware is OTG-ready
591  * @g: controller that might have a Mini-AB connector
592  *
593  * This is a runtime test, since kernels with a USB-OTG stack sometimes
594  * run on boards which only have a Mini-B (or Mini-A) connector.
595  */
gadget_is_otg(struct usb_gadget * g)596 static inline int gadget_is_otg(struct usb_gadget *g)
597 {
598 #ifdef CONFIG_USB_OTG
599 	return g->is_otg;
600 #else
601 	return 0;
602 #endif
603 }
604 
605 /**
606  * usb_gadget_frame_number - returns the current frame number
607  * @gadget: controller that reports the frame number
608  *
609  * Returns the usb frame number, normally eleven bits from a SOF packet,
610  * or negative errno if this device doesn't support this capability.
611  */
usb_gadget_frame_number(struct usb_gadget * gadget)612 static inline int usb_gadget_frame_number(struct usb_gadget *gadget)
613 {
614 	return gadget->ops->get_frame(gadget);
615 }
616 
617 /**
618  * usb_gadget_wakeup - tries to wake up the host connected to this gadget
619  * @gadget: controller used to wake up the host
620  *
621  * Returns zero on success, else negative error code if the hardware
622  * doesn't support such attempts, or its support has not been enabled
623  * by the usb host.  Drivers must return device descriptors that report
624  * their ability to support this, or hosts won't enable it.
625  *
626  * This may also try to use SRP to wake the host and start enumeration,
627  * even if OTG isn't otherwise in use.  OTG devices may also start
628  * remote wakeup even when hosts don't explicitly enable it.
629  */
usb_gadget_wakeup(struct usb_gadget * gadget)630 static inline int usb_gadget_wakeup(struct usb_gadget *gadget)
631 {
632 	if (!gadget->ops->wakeup)
633 		return -EOPNOTSUPP;
634 	return gadget->ops->wakeup(gadget);
635 }
636 
637 /**
638  * usb_gadget_set_selfpowered - sets the device selfpowered feature.
639  * @gadget:the device being declared as self-powered
640  *
641  * this affects the device status reported by the hardware driver
642  * to reflect that it now has a local power supply.
643  *
644  * returns zero on success, else negative errno.
645  */
usb_gadget_set_selfpowered(struct usb_gadget * gadget)646 static inline int usb_gadget_set_selfpowered(struct usb_gadget *gadget)
647 {
648 	if (!gadget->ops->set_selfpowered)
649 		return -EOPNOTSUPP;
650 	return gadget->ops->set_selfpowered(gadget, 1);
651 }
652 
653 /**
654  * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
655  * @gadget:the device being declared as bus-powered
656  *
657  * this affects the device status reported by the hardware driver.
658  * some hardware may not support bus-powered operation, in which
659  * case this feature's value can never change.
660  *
661  * returns zero on success, else negative errno.
662  */
usb_gadget_clear_selfpowered(struct usb_gadget * gadget)663 static inline int usb_gadget_clear_selfpowered(struct usb_gadget *gadget)
664 {
665 	if (!gadget->ops->set_selfpowered)
666 		return -EOPNOTSUPP;
667 	return gadget->ops->set_selfpowered(gadget, 0);
668 }
669 
670 /**
671  * usb_gadget_vbus_connect - Notify controller that VBUS is powered
672  * @gadget:The device which now has VBUS power.
673  * Context: can sleep
674  *
675  * This call is used by a driver for an external transceiver (or GPIO)
676  * that detects a VBUS power session starting.  Common responses include
677  * resuming the controller, activating the D+ (or D-) pullup to let the
678  * host detect that a USB device is attached, and starting to draw power
679  * (8mA or possibly more, especially after SET_CONFIGURATION).
680  *
681  * Returns zero on success, else negative errno.
682  */
usb_gadget_vbus_connect(struct usb_gadget * gadget)683 static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget)
684 {
685 	if (!gadget->ops->vbus_session)
686 		return -EOPNOTSUPP;
687 	return gadget->ops->vbus_session(gadget, 1);
688 }
689 
690 /**
691  * usb_gadget_vbus_draw - constrain controller's VBUS power usage
692  * @gadget:The device whose VBUS usage is being described
693  * @mA:How much current to draw, in milliAmperes.  This should be twice
694  *	the value listed in the configuration descriptor bMaxPower field.
695  *
696  * This call is used by gadget drivers during SET_CONFIGURATION calls,
697  * reporting how much power the device may consume.  For example, this
698  * could affect how quickly batteries are recharged.
699  *
700  * Returns zero on success, else negative errno.
701  */
usb_gadget_vbus_draw(struct usb_gadget * gadget,unsigned mA)702 static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
703 {
704 	if (!gadget->ops->vbus_draw)
705 		return -EOPNOTSUPP;
706 	return gadget->ops->vbus_draw(gadget, mA);
707 }
708 
709 /**
710  * usb_gadget_vbus_disconnect - notify controller about VBUS session end
711  * @gadget:the device whose VBUS supply is being described
712  * Context: can sleep
713  *
714  * This call is used by a driver for an external transceiver (or GPIO)
715  * that detects a VBUS power session ending.  Common responses include
716  * reversing everything done in usb_gadget_vbus_connect().
717  *
718  * Returns zero on success, else negative errno.
719  */
usb_gadget_vbus_disconnect(struct usb_gadget * gadget)720 static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
721 {
722 	if (!gadget->ops->vbus_session)
723 		return -EOPNOTSUPP;
724 	return gadget->ops->vbus_session(gadget, 0);
725 }
726 
727 /**
728  * usb_gadget_connect - software-controlled connect to USB host
729  * @gadget:the peripheral being connected
730  *
731  * Enables the D+ (or potentially D-) pullup.  The host will start
732  * enumerating this gadget when the pullup is active and a VBUS session
733  * is active (the link is powered).  This pullup is always enabled unless
734  * usb_gadget_disconnect() has been used to disable it.
735  *
736  * Returns zero on success, else negative errno.
737  */
usb_gadget_connect(struct usb_gadget * gadget)738 static inline int usb_gadget_connect(struct usb_gadget *gadget)
739 {
740 	if (!gadget->ops->pullup)
741 		return -EOPNOTSUPP;
742 	return gadget->ops->pullup(gadget, 1);
743 }
744 
745 /**
746  * usb_gadget_disconnect - software-controlled disconnect from USB host
747  * @gadget:the peripheral being disconnected
748  *
749  * Disables the D+ (or potentially D-) pullup, which the host may see
750  * as a disconnect (when a VBUS session is active).  Not all systems
751  * support software pullup controls.
752  *
753  * This routine may be used during the gadget driver bind() call to prevent
754  * the peripheral from ever being visible to the USB host, unless later
755  * usb_gadget_connect() is called.  For example, user mode components may
756  * need to be activated before the system can talk to hosts.
757  *
758  * Returns zero on success, else negative errno.
759  */
usb_gadget_disconnect(struct usb_gadget * gadget)760 static inline int usb_gadget_disconnect(struct usb_gadget *gadget)
761 {
762 	if (!gadget->ops->pullup)
763 		return -EOPNOTSUPP;
764 	return gadget->ops->pullup(gadget, 0);
765 }
766 
767 
768 /*-------------------------------------------------------------------------*/
769 
770 /**
771  * struct usb_gadget_driver - driver for usb 'slave' devices
772  * @function: String describing the gadget's function
773  * @max_speed: Highest speed the driver handles.
774  * @setup: Invoked for ep0 control requests that aren't handled by
775  *	the hardware level driver. Most calls must be handled by
776  *	the gadget driver, including descriptor and configuration
777  *	management.  The 16 bit members of the setup data are in
778  *	USB byte order. Called in_interrupt; this may not sleep.  Driver
779  *	queues a response to ep0, or returns negative to stall.
780  * @disconnect: Invoked after all transfers have been stopped,
781  *	when the host is disconnected.  May be called in_interrupt; this
782  *	may not sleep.  Some devices can't detect disconnect, so this might
783  *	not be called except as part of controller shutdown.
784  * @unbind: Invoked when the driver is unbound from a gadget,
785  *	usually from rmmod (after a disconnect is reported).
786  *	Called in a context that permits sleeping.
787  * @suspend: Invoked on USB suspend.  May be called in_interrupt.
788  * @resume: Invoked on USB resume.  May be called in_interrupt.
789  * @driver: Driver model state for this driver.
790  *
791  * Devices are disabled till a gadget driver successfully bind()s, which
792  * means the driver will handle setup() requests needed to enumerate (and
793  * meet "chapter 9" requirements) then do some useful work.
794  *
795  * If gadget->is_otg is true, the gadget driver must provide an OTG
796  * descriptor during enumeration, or else fail the bind() call.  In such
797  * cases, no USB traffic may flow until both bind() returns without
798  * having called usb_gadget_disconnect(), and the USB host stack has
799  * initialized.
800  *
801  * Drivers use hardware-specific knowledge to configure the usb hardware.
802  * endpoint addressing is only one of several hardware characteristics that
803  * are in descriptors the ep0 implementation returns from setup() calls.
804  *
805  * Except for ep0 implementation, most driver code shouldn't need change to
806  * run on top of different usb controllers.  It'll use endpoints set up by
807  * that ep0 implementation.
808  *
809  * The usb controller driver handles a few standard usb requests.  Those
810  * include set_address, and feature flags for devices, interfaces, and
811  * endpoints (the get_status, set_feature, and clear_feature requests).
812  *
813  * Accordingly, the driver's setup() callback must always implement all
814  * get_descriptor requests, returning at least a device descriptor and
815  * a configuration descriptor.  Drivers must make sure the endpoint
816  * descriptors match any hardware constraints. Some hardware also constrains
817  * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
818  *
819  * The driver's setup() callback must also implement set_configuration,
820  * and should also implement set_interface, get_configuration, and
821  * get_interface.  Setting a configuration (or interface) is where
822  * endpoints should be activated or (config 0) shut down.
823  *
824  * (Note that only the default control endpoint is supported.  Neither
825  * hosts nor devices generally support control traffic except to ep0.)
826  *
827  * Most devices will ignore USB suspend/resume operations, and so will
828  * not provide those callbacks.  However, some may need to change modes
829  * when the host is not longer directing those activities.  For example,
830  * local controls (buttons, dials, etc) may need to be re-enabled since
831  * the (remote) host can't do that any longer; or an error state might
832  * be cleared, to make the device behave identically whether or not
833  * power is maintained.
834  */
835 struct usb_gadget_driver {
836 	char			*function;
837 	enum usb_device_speed	max_speed;
838 	void			(*unbind)(struct usb_gadget *);
839 	int			(*setup)(struct usb_gadget *,
840 					const struct usb_ctrlrequest *);
841 	void			(*disconnect)(struct usb_gadget *);
842 	void			(*suspend)(struct usb_gadget *);
843 	void			(*resume)(struct usb_gadget *);
844 
845 	/* FIXME support safe rmmod */
846 	struct device_driver	driver;
847 };
848 
849 
850 
851 /*-------------------------------------------------------------------------*/
852 
853 /* driver modules register and unregister, as usual.
854  * these calls must be made in a context that can sleep.
855  *
856  * these will usually be implemented directly by the hardware-dependent
857  * usb bus interface driver, which will only support a single driver.
858  */
859 
860 /**
861  * usb_gadget_probe_driver - probe a gadget driver
862  * @driver: the driver being registered
863  * @bind: the driver's bind callback
864  * Context: can sleep
865  *
866  * Call this in your gadget driver's module initialization function,
867  * to tell the underlying usb controller driver about your driver.
868  * The @bind() function will be called to bind it to a gadget before this
869  * registration call returns.  It's expected that the @bind() function will
870  * be in init sections.
871  */
872 int usb_gadget_probe_driver(struct usb_gadget_driver *driver,
873 		int (*bind)(struct usb_gadget *));
874 
875 /**
876  * usb_gadget_unregister_driver - unregister a gadget driver
877  * @driver:the driver being unregistered
878  * Context: can sleep
879  *
880  * Call this in your gadget driver's module cleanup function,
881  * to tell the underlying usb controller that your driver is
882  * going away.  If the controller is connected to a USB host,
883  * it will first disconnect().  The driver is also requested
884  * to unbind() and clean up any device state, before this procedure
885  * finally returns.  It's expected that the unbind() functions
886  * will in in exit sections, so may not be linked in some kernels.
887  */
888 int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);
889 
890 extern int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget);
891 extern void usb_del_gadget_udc(struct usb_gadget *gadget);
892 
893 /*-------------------------------------------------------------------------*/
894 
895 /* utility to simplify dealing with string descriptors */
896 
897 /**
898  * struct usb_string - wraps a C string and its USB id
899  * @id:the (nonzero) ID for this string
900  * @s:the string, in UTF-8 encoding
901  *
902  * If you're using usb_gadget_get_string(), use this to wrap a string
903  * together with its ID.
904  */
905 struct usb_string {
906 	u8			id;
907 	const char		*s;
908 };
909 
910 /**
911  * struct usb_gadget_strings - a set of USB strings in a given language
912  * @language:identifies the strings' language (0x0409 for en-us)
913  * @strings:array of strings with their ids
914  *
915  * If you're using usb_gadget_get_string(), use this to wrap all the
916  * strings for a given language.
917  */
918 struct usb_gadget_strings {
919 	u16			language;	/* 0x0409 for en-us */
920 	struct usb_string	*strings;
921 };
922 
923 /* put descriptor for string with that id into buf (buflen >= 256) */
924 int usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf);
925 
926 /*-------------------------------------------------------------------------*/
927 
928 /* utility to simplify managing config descriptors */
929 
930 /* write vector of descriptors into buffer */
931 int usb_descriptor_fillbuf(void *, unsigned,
932 		const struct usb_descriptor_header **);
933 
934 /* build config descriptor from single descriptor vector */
935 int usb_gadget_config_buf(const struct usb_config_descriptor *config,
936 	void *buf, unsigned buflen, const struct usb_descriptor_header **desc);
937 
938 /* copy a NULL-terminated vector of descriptors */
939 struct usb_descriptor_header **usb_copy_descriptors(
940 		struct usb_descriptor_header **);
941 
942 /**
943  * usb_free_descriptors - free descriptors returned by usb_copy_descriptors()
944  * @v: vector of descriptors
945  */
usb_free_descriptors(struct usb_descriptor_header ** v)946 static inline void usb_free_descriptors(struct usb_descriptor_header **v)
947 {
948 	kfree(v);
949 }
950 
951 /*-------------------------------------------------------------------------*/
952 
953 /* utility to simplify map/unmap of usb_requests to/from DMA */
954 
955 extern int usb_gadget_map_request(struct usb_gadget *gadget,
956 		struct usb_request *req, int is_in);
957 
958 extern void usb_gadget_unmap_request(struct usb_gadget *gadget,
959 		struct usb_request *req, int is_in);
960 
961 /*-------------------------------------------------------------------------*/
962 
963 /* utility wrapping a simple endpoint selection policy */
964 
965 extern struct usb_ep *usb_ep_autoconfig(struct usb_gadget *,
966 			struct usb_endpoint_descriptor *);
967 
968 
969 extern struct usb_ep *usb_ep_autoconfig_ss(struct usb_gadget *,
970 			struct usb_endpoint_descriptor *,
971 			struct usb_ss_ep_comp_descriptor *);
972 
973 extern void usb_ep_autoconfig_reset(struct usb_gadget *);
974 
975 #endif /* __LINUX_USB_GADGET_H */
976