summaryrefslogtreecommitdiffstats
path: root/include/linux/usb/gadget.h
blob: c3a61853cd1306f7a34cdc9b26a9e08b39c49ce2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
/*
 * <linux/usb/gadget.h>
 *
 * We call the USB code inside a Linux-based peripheral device a "gadget"
 * driver, except for the hardware-specific bus glue.  One USB host can
 * master many USB gadgets, but the gadgets are only slaved to one host.
 *
 *
 * (C) Copyright 2002-2004 by David Brownell
 * All Rights Reserved.
 *
 * This software is licensed under the GNU GPL version 2.
 */

#ifndef __LINUX_USB_GADGET_H
#define __LINUX_USB_GADGET_H

#include <linux/device.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/scatterlist.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <linux/usb/ch9.h>

struct usb_ep;

/**
 * struct usb_request - describes one i/o request
 * @buf: Buffer used for data.  Always provide this; some controllers
 *	only use PIO, or don't use DMA for some endpoints.
 * @dma: DMA address corresponding to 'buf'.  If you don't set this
 *	field, and the usb controller needs one, it is responsible
 *	for mapping and unmapping the buffer.
 * @sg: a scatterlist for SG-capable controllers.
 * @num_sgs: number of SG entries
 * @num_mapped_sgs: number of SG entries mapped to DMA (internal)
 * @length: Length of that data
 * @stream_id: The stream id, when USB3.0 bulk streams are being used
 * @no_interrupt: If true, hints that no completion irq is needed.
 *	Helpful sometimes with deep request queues that are handled
 *	directly by DMA controllers.
 * @zero: If true, when writing data, makes the last packet be "short"
 *     by adding a zero length packet as needed;
 * @short_not_ok: When reading data, makes short packets be
 *     treated as errors (queue stops advancing till cleanup).
 * @complete: Function called when request completes, so this request and
 *	its buffer may be re-used.  The function will always be called with
 *	interrupts disabled, and it must not sleep.
 *	Reads terminate with a short packet, or when the buffer fills,
 *	whichever comes first.  When writes terminate, some data bytes
 *	will usually still be in flight (often in a hardware fifo).
 *	Errors (for reads or writes) stop the queue from advancing
 *	until the completion function returns, so that any transfers
 *	invalidated by the error may first be dequeued.
 * @context: For use by the completion callback
 * @list: For use by the gadget driver.
 * @status: Reports completion code, zero or a negative errno.
 *	Normally, faults block the transfer queue from advancing until
 *	the completion callback returns.
 *	Code "-ESHUTDOWN" indicates completion caused by device disconnect,
 *	or when the driver disabled the endpoint.
 * @actual: Reports bytes transferred to/from the buffer.  For reads (OUT
 *	transfers) this may be less than the requested length.  If the
 *	short_not_ok flag is set, short reads are treated as errors
 *	even when status otherwise indicates successful completion.
 *	Note that for writes (IN transfers) some data bytes may still
 *	reside in a device-side FIFO when the request is reported as
 *	complete.
 *
 * These are allocated/freed through the endpoint they're used with.  The
 * hardware's driver can add extra per-request data to the memory it returns,
 * which often avoids separate memory allocations (potential failures),
 * later when the request is queued.
 *
 * Request flags affect request handling, such as whether a zero length
 * packet is written (the "zero" flag), whether a short read should be
 * treated as an error (blocking request queue advance, the "short_not_ok"
 * flag), or hinting that an interrupt is not required (the "no_interrupt"
 * flag, for use with deep request queues).
 *
 * Bulk endpoints can use any size buffers, and can also be used for interrupt
 * transfers. interrupt-only endpoints can be much less functional.
 *
 * NOTE:  this is analogous to 'struct urb' on the host side, except that
 * it's thinner and promotes more pre-allocation.
 */

struct usb_request {
	void			*buf;
	unsigned		length;
	dma_addr_t		dma;

	struct scatterlist	*sg;
	unsigned		num_sgs;
	unsigned		num_mapped_sgs;

	unsigned		stream_id:16;
	unsigned		no_interrupt:1;
	unsigned		zero:1;
	unsigned		short_not_ok:1;

	void			(*complete)(struct usb_ep *ep,
					struct usb_request *req);
	void			*context;
	struct list_head	list;

	int			status;
	unsigned		actual;
};

/*-------------------------------------------------------------------------*/

/* endpoint-specific parts of the api to the usb controller hardware.
 * unlike the urb model, (de)multiplexing layers are not required.
 * (so this api could slash overhead if used on the host side...)
 *
 * note that device side usb controllers commonly differ in how many
 * endpoints they support, as well as their capabilities.
 */
struct usb_ep_ops {
	int (*enable) (struct usb_ep *ep,
		const struct usb_endpoint_descriptor *desc);
	int (*disable) (struct usb_ep *ep);

	struct usb_request *(*alloc_request) (struct usb_ep *ep,
		gfp_t gfp_flags);
	void (*free_request) (struct usb_ep *ep, struct usb_request *req);

	int (*queue) (struct usb_ep *ep, struct usb_request *req,
		gfp_t gfp_flags);
	int (*dequeue) (struct usb_ep *ep, struct usb_request *req);

	int (*set_halt) (struct usb_ep *ep, int value);
	int (*set_wedge) (struct usb_ep *ep);

	int (*fifo_status) (struct usb_ep *ep);
	void (*fifo_flush) (struct usb_ep *ep);
};

/**
 * struct usb_ep - device side representation of USB endpoint
 * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
 * @ops: Function pointers used to access hardware-specific operations.
 * @ep_list:the gadget's ep_list holds all of its endpoints
 * @maxpacket:The maximum packet size used on this endpoint.  The initial
 *	value can sometimes be reduced (hardware allowing), according to
 *      the endpoint descriptor used to configure the endpoint.
 * @maxpacket_limit:The maximum packet size value which can be handled by this
 *	endpoint. It's set once by UDC driver when endpoint is initialized, and
 *	should not be changed. Should not be confused with maxpacket.
 * @max_streams: The maximum number of streams supported
 *	by this EP (0 - 16, actual number is 2^n)
 * @mult: multiplier, 'mult' value for SS Isoc EPs
 * @maxburst: the maximum number of bursts supported by this EP (for usb3)
 * @driver_data:for use by the gadget driver.
 * @address: used to identify the endpoint when finding descriptor that
 *	matches connection speed
 * @desc: endpoint descriptor.  This pointer is set before the endpoint is
 *	enabled and remains valid until the endpoint is disabled.
 * @comp_desc: In case of SuperSpeed support, this is the endpoint companion
 *	descriptor that is used to configure the endpoint
 *
 * the bus controller driver lists all the general purpose endpoints in
 * gadget->ep_list.  the control endpoint (gadget->ep0) is not in that list,
 * and is accessed only in response to a driver setup() callback.
 */
struct usb_ep {
	void			*driver_data;

	const char		*name;
	const struct usb_ep_ops	*ops;
	struct list_head	ep_list;
	unsigned		maxpacket:16;
	unsigned		maxpacket_limit:16;
	unsigned		max_streams:16;
	unsigned		mult:2;
	unsigned		maxburst:5;
	u8			address;
	const struct usb_endpoint_descriptor	*desc;
	const struct usb_ss_ep_comp_descriptor	*comp_desc;
};

/*-------------------------------------------------------------------------*/

/**
 * usb_ep_set_maxpacket_limit - set maximum packet size limit for endpoint
 * @ep:the endpoint being configured
 * @maxpacket_limit:value of maximum packet size limit
 *
 * This function shoud be used only in UDC drivers to initialize endpoint
 * (usually in probe function).
 */
static inline void usb_ep_set_maxpacket_limit(struct usb_ep *ep,
					      unsigned maxpacket_limit)
{
	ep->maxpacket_limit = maxpacket_limit;
	ep->maxpacket = maxpacket_limit;
}

/**
 * usb_ep_enable - configure endpoint, making it usable
 * @ep:the endpoint being configured.  may not be the endpoint named "ep0".
 *	drivers discover endpoints through the ep_list of a usb_gadget.
 *
 * When configurations are set, or when interface settings change, the driver
 * will enable or disable the relevant endpoints.  while it is enabled, an
 * endpoint may be used for i/o until the driver receives a disconnect() from
 * the host or until the endpoint is disabled.
 *
 * the ep0 implementation (which calls this routine) must ensure that the
 * hardware capabilities of each endpoint match the descriptor provided
 * for it.  for example, an endpoint named "ep2in-bulk" would be usable
 * for interrupt transfers as well as bulk, but it likely couldn't be used
 * for iso transfers or for endpoint 14.  some endpoints are fully
 * configurable, with more generic names like "ep-a".  (remember that for
 * USB, "in" means "towards the USB master".)
 *
 * returns zero, or a negative error code.
 */
static inline int usb_ep_enable(struct usb_ep *ep)
{
	return ep->ops->enable(ep, ep->desc);
}

/**
 * usb_ep_disable - endpoint is no longer usable
 * @ep:the endpoint being unconfigured.  may not be the endpoint named "ep0".
 *
 * no other task may be using this endpoint when this is called.
 * any pending and uncompleted requests will complete with status
 * indicating disconnect (-ESHUTDOWN) before this call returns.
 * gadget drivers must call usb_ep_enable() again before queueing
 * requests to the endpoint.
 *
 * returns zero, or a negative error code.
 */
static inline int usb_ep_disable(struct usb_ep *ep)
{
	return ep->ops->disable(ep);
}

/**
 * usb_ep_alloc_request - allocate a request object to use with this endpoint
 * @ep:the endpoint to be used with with the request
 * @gfp_flags:GFP_* flags to use
 *
 * Request objects must be allocated with this call, since they normally
 * need controller-specific setup and may even need endpoint-specific
 * resources such as allocation of DMA descriptors.
 * Requests may be submitted with usb_ep_queue(), and receive a single
 * completion callback.  Free requests with usb_ep_free_request(), when
 * they are no longer needed.
 *
 * Returns the request, or null if one could not be allocated.
 */
static inline struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
						       gfp_t gfp_flags)
{
	return ep->ops->alloc_request(ep, gfp_flags);
}

/**
 * usb_ep_free_request - frees a request object
 * @ep:the endpoint associated with the request
 * @req:the request being freed
 *
 * Reverses the effect of usb_ep_alloc_request().
 * Caller guarantees the request is not queued, and that it will
 * no longer be requeued (or otherwise used).
 */
static inline void usb_ep_free_request(struct usb_ep *ep,
				       struct usb_request *req)
{
	ep->ops->free_request(ep, req);
}

/**
 * usb_ep_queue - queues (submits) an I/O request to an endpoint.
 * @ep:the endpoint associated with the request
 * @req:the request being submitted
 * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
 *	pre-allocate all necessary memory with the request.
 *
 * This tells the device controller to perform the specified request through
 * that endpoint (reading or writing a buffer).  When the request completes,
 * including being canceled by usb_ep_dequeue(), the request's completion
 * routine is called to return the request to the driver.  Any endpoint
 * (except control endpoints like ep0) may have more than one transfer
 * request queued; they complete in FIFO order.  Once a gadget driver
 * submits a request, that request may not be examined or modified until it
 * is given back to that driver through the completion callback.
 *
 * Each request is turned into one or more packets.  The controller driver
 * never merges adjacent requests into the same packet.  OUT transfers
 * will sometimes use data that's already buffered in the hardware.
 * Drivers can rely on the fact that the first byte of the request's buffer
 * always corresponds to the first byte of some USB packet, for both
 * IN and OUT transfers.
 *
 * Bulk endpoints can queue any amount of data; the transfer is packetized
 * automatically.  The last packet will be short if the request doesn't fill it
 * out completely.  Zero length packets (ZLPs) should be avoided in portable
 * protocols since not all usb hardware can successfully handle zero length
 * packets.  (ZLPs may be explicitly written, and may be implicitly written if
 * the request 'zero' flag is set.)  Bulk endpoints may also be used
 * for interrupt transfers; but the reverse is not true, and some endpoints
 * won't support every interrupt transfer.  (Such as 768 byte packets.)
 *
 * Interrupt-only endpoints are less functional than bulk endpoints, for
 * example by not supporting queueing or not handling buffers that are
 * larger than the endpoint's maxpacket size.  They may also treat data
 * toggle differently.
 *
 * Control endpoints ... after getting a setup() callback, the driver queues
 * one response (even if it would be zero length).  That enables the
 * status ack, after transferring data as specified in the response.  Setup
 * functions may return negative error codes to generate protocol stalls.
 * (Note that some USB device controllers disallow protocol stall responses
 * in some cases.)  When control responses are deferred (the response is
 * written after the setup callback returns), then usb_ep_set_halt() may be
 * used on ep0 to trigger protocol stalls.  Depending on the controller,
 * it may not be possible to trigger a status-stage protocol stall when the
 * data stage is over, that is, from within the response's completion
 * routine.
 *
 * For periodic endpoints, like interrupt or isochronous ones, the usb host
 * arranges to poll once per interval, and the gadget driver usually will
 * have queued some data to transfer at that time.
 *
 * Returns zero, or a negative error code.  Endpoints that are not enabled
 * report errors; errors will also be
 * reported when the usb peripheral is disconnected.
 */
static inline int usb_ep_queue(struct usb_ep *ep,
			       struct usb_request *req, gfp_t gfp_flags)
{
	return ep->ops->queue(ep, req, gfp_flags);
}

/**
 * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
 * @ep:the endpoint associated with the request
 * @req:the request being canceled
 *
 * if the request is still active on the endpoint, it is dequeued and its
 * completion routine is called (with status -ECONNRESET); else a negative
 * error code is returned.
 *
 * note that some hardware can't clear out write fifos (to unlink the request
 * at the head of the queue) except as part of disconnecting from usb.  such
 * restrictions prevent drivers from supporting configuration changes,
 * even to configuration zero (a "chapter 9" requirement).
 */
static inline int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
{
	return ep->ops->dequeue(ep, req);
}

/**
 * usb_ep_set_halt - sets the endpoint halt feature.
 * @ep: the non-isochronous endpoint being stalled
 *
 * Use this to stall an endpoint, perhaps as an error report.
 * Except for control endpoints,
 * the endpoint stays halted (will not stream any data) until the host
 * clears this feature; drivers may need to empty the endpoint's request
 * queue first, to make sure no inappropriate transfers happen.
 *
 * Note that while an endpoint CLEAR_FEATURE will be invisible to the
 * gadget driver, a SET_INTERFACE will not be.  To reset endpoints for the
 * current altsetting, see usb_ep_clear_halt().  When switching altsettings,
 * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
 *
 * Returns zero, or a negative error code.  On success, this call sets
 * underlying hardware state that blocks data transfers.
 * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
 * transfer requests are still queued, or if the controller hardware
 * (usually a FIFO) still holds bytes that the host hasn't collected.
 */
static inline int usb_ep_set_halt(struct usb_ep *ep)
{
	return ep->ops->set_halt(ep, 1);
}

/**
 * usb_ep_clear_halt - clears endpoint halt, and resets toggle
 * @ep:the bulk or interrupt endpoint being reset
 *
 * Use this when responding to the standard usb "set interface" request,
 * for endpoints that aren't reconfigured, after clearing any other state
 * in the endpoint's i/o queue.
 *
 * Returns zero, or a negative error code.  On success, this call clears
 * the underlying hardware state reflecting endpoint halt and data toggle.
 * Note that some hardware can't support this request (like pxa2xx_udc),
 * and accordingly can't correctly implement interface altsettings.
 */
static inline int usb_ep_clear_halt(struct usb_ep *ep)
{
	return ep->ops->set_halt(ep, 0);
}

/**
 * usb_ep_set_wedge - sets the halt feature and ignores clear requests
 * @ep: the endpoint being wedged
 *
 * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT)
 * requests. If the gadget driver clears the halt status, it will
 * automatically unwedge the endpoint.
 *
 * Returns zero on success, else negative errno.
 */
static inline int
usb_ep_set_wedge(struct usb_ep *ep)
{
	if (ep->ops->set_wedge)
		return ep->ops->set_wedge(ep);
	else
		return ep->ops->set_halt(ep, 1);
}

/**
 * usb_ep_fifo_status - returns number of bytes in fifo, or error
 * @ep: the endpoint whose fifo status is being checked.
 *
 * FIFO endpoints may have "unclaimed data" in them in certain cases,
 * such as after aborted transfers.  Hosts may not have collected all
 * the IN data written by the gadget driver (and reported by a request
 * completion).  The gadget driver may not have collected all the data
 * written OUT to it by the host.  Drivers that need precise handling for
 * fault reporting or recovery may need to use this call.
 *
 * This returns the number of such bytes in the fifo, or a negative
 * errno if the endpoint doesn't use a FIFO or doesn't support such
 * precise handling.
 */
static inline int usb_ep_fifo_status(struct usb_ep *ep)
{
	if (ep->ops->fifo_status)
		return ep->ops->fifo_status(ep);
	else
		return -EOPNOTSUPP;
}

/**
 * usb_ep_fifo_flush - flushes contents of a fifo
 * @ep: the endpoint whose fifo is being flushed.
 *
 * This call may be used to flush the "unclaimed data" that may exist in
 * an endpoint fifo after abnormal transaction terminations.  The call
 * must never be used except when endpoint is not being used for any
 * protocol translation.
 */
static inline void usb_ep_fifo_flush(struct usb_ep *ep)
{
	if (ep->ops->fifo_flush)
		ep->ops->fifo_flush(ep);
}


/*-------------------------------------------------------------------------*/

struct usb_dcd_config_params {
	__u8  bU1devExitLat;	/* U1 Device exit Latency */
#define USB_DEFAULT_U1_DEV_EXIT_LAT	0x01	/* Less then 1 microsec */
	__le16 bU2DevExitLat;	/* U2 Device exit Latency */
#define USB_DEFAULT_U2_DEV_EXIT_LAT	0x1F4	/* Less then 500 microsec */
};


struct usb_gadget;
struct usb_gadget_driver;

/* the rest of the api to the controller hardware: device operations,
 * which don't involve endpoints (or i/o).
 */
struct usb_gadget_ops {
	int	(*get_frame)(struct usb_gadget *);
	int	(*wakeup)(struct usb_gadget *);
	int	(*set_selfpowered) (struct usb_gadget *, int is_selfpowered);
	int	(*vbus_session) (struct usb_gadget *, int is_active);
	int	(*vbus_draw) (struct usb_gadget *, unsigned mA);
	int	(*pullup) (struct usb_gadget *, int is_on);
	int	(*ioctl)(struct usb_gadget *,
				unsigned code, unsigned long param);
	void	(*get_config_params)(struct usb_dcd_config_params *);
	int	(*udc_start)(struct usb_gadget *,
			struct usb_gadget_driver *);
	int	(*udc_stop)(struct usb_gadget *,
			struct usb_gadget_driver *);
};

/**
 * struct usb_gadget - represents a usb slave device
 * @work: (internal use) Workqueue to be used for sysfs_notify()
 * @ops: Function pointers used to access hardware-specific operations.
 * @ep0: Endpoint zero, used when reading or writing responses to
 *	driver setup() requests
 * @ep_list: List of other endpoints supported by the device.
 * @speed: Speed of current connection to USB host.
 * @max_speed: Maximal speed the UDC can handle.  UDC must support this
 *      and all slower speeds.
 * @state: the state we are now (attached, suspended, configured, etc)
 * @name: Identifies the controller hardware type.  Used in diagnostics
 *	and sometimes configuration.
 * @dev: Driver model state for this abstract device.
 * @out_epnum: last used out ep number
 * @in_epnum: last used in ep number
 * @sg_supported: true if we can handle scatter-gather
 * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
 *	gadget driver must provide a USB OTG descriptor.
 * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable
 *	is in the Mini-AB jack, and HNP has been used to switch roles
 *	so that the "A" device currently acts as A-Peripheral, not A-Host.
 * @a_hnp_support: OTG device feature flag, indicating that the A-Host
 *	supports HNP at this port.
 * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host
 *	only supports HNP on a different root port.
 * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
 *	enabled HNP support.
 * @quirk_ep_out_aligned_size: epout requires buffer size to be aligned to
 *	MaxPacketSize.
 *
 * Gadgets have a mostly-portable "gadget driver" implementing device
 * functions, handling all usb configurations and interfaces.  Gadget
 * drivers talk to hardware-specific code indirectly, through ops vectors.
 * That insulates the gadget driver from hardware details, and packages
 * the hardware endpoints through generic i/o queues.  The "usb_gadget"
 * and "usb_ep" interfaces provide that insulation from the hardware.
 *
 * Except for the driver data, all fields in this structure are
 * read-only to the gadget driver.  That driver data is part of the
 * "driver model" infrastructure in 2.6 (and later) kernels, and for
 * earlier systems is grouped in a similar structure that's not known
 * to the rest of the kernel.
 *
 * Values of the three OTG device feature flags are updated before the
 * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before
 * driver suspend() calls.  They are valid only when is_otg, and when the
 * device is acting as a B-Peripheral (so is_a_peripheral is false).
 */
struct usb_gadget {
	struct work_struct		work;
	/* readonly to gadget driver */
	const struct usb_gadget_ops	*ops;
	struct usb_ep			*ep0;
	struct list_head		ep_list;	/* of usb_ep */
	enum usb_device_speed		speed;
	enum usb_device_speed		max_speed;
	enum usb_device_state		state;
	const char			*name;
	struct device			dev;
	unsigned			out_epnum;
	unsigned			in_epnum;

	unsigned			sg_supported:1;
	unsigned			is_otg:1;
	unsigned			is_a_peripheral:1;
	unsigned			b_hnp_enable:1;
	unsigned			a_hnp_support:1;
	unsigned			a_alt_hnp_support:1;
	unsigned			quirk_ep_out_aligned_size:1;
};
#define work_to_gadget(w)	(container_of((w), struct usb_gadget, work))

static inline void set_gadget_data(struct usb_gadget *gadget, void *data)
	{ dev_set_drvdata(&gadget->dev, data); }
static inline void *get_gadget_data(struct usb_gadget *gadget)
	{ return dev_get_drvdata(&gadget->dev); }
static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
{
	return container_of(dev, struct usb_gadget, dev);
}

/* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
#define gadget_for_each_ep(tmp, gadget) \
	list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)


/**
 * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
 *	requires quirk_ep_out_aligned_size, otherwise reguens len.
 * @g: controller to check for quirk
 * @ep: the endpoint whose maxpacketsize is used to align @len
 * @len: buffer size's length to align to @ep's maxpacketsize
 *
 * This helper is used in case it's required for any reason to check and maybe
 * align buffer's size to an ep's maxpacketsize.
 */
static inline size_t
usb_ep_align_maybe(struct usb_gadget *g, struct usb_ep *ep, size_t len)
{
	return !g->quirk_ep_out_aligned_size ? len :
			round_up(len, (size_t)ep->desc->wMaxPacketSize);
}

/**
 * gadget_is_dualspeed - return true iff the hardware handles high speed
 * @g: controller that might support both high and full speeds
 */
static inline int gadget_is_dualspeed(struct usb_gadget *g)
{
	return g->max_speed >= USB_SPEED_HIGH;
}

/**
 * gadget_is_superspeed() - return true if the hardware handles superspeed
 * @g: controller that might support superspeed
 */
static inline int gadget_is_superspeed(struct usb_gadget *g)
{
	return g->max_speed >= USB_SPEED_SUPER;
}

/**
 * gadget_is_otg - return true iff the hardware is OTG-ready
 * @g: controller that might have a Mini-AB connector
 *
 * This is a runtime test, since kernels with a USB-OTG stack sometimes
 * run on boards which only have a Mini-B (or Mini-A) connector.
 */
static inline int gadget_is_otg(struct usb_gadget *g)
{
#ifdef CONFIG_USB_OTG
	return g->is_otg;
#else
	return 0;
#endif
}

/**
 * usb_gadget_frame_number - returns the current frame number
 * @gadget: controller that reports the frame number
 *
 * Returns the usb frame number, normally eleven bits from a SOF packet,
 * or negative errno if this device doesn't support this capability.
 */
static inline int usb_gadget_frame_number(struct usb_gadget *gadget)
{
	return gadget->ops->get_frame(gadget);
}

/**
 * usb_gadget_wakeup - tries to wake up the host connected to this gadget
 * @gadget: controller used to wake up the host
 *
 * Returns zero on success, else negative error code if the hardware
 * doesn't support such attempts, or its support has not been enabled
 * by the usb host.  Drivers must return device descriptors that report
 * their ability to support this, or hosts won't enable it.
 *
 * This may also try to use SRP to wake the host and start enumeration,
 * even if OTG isn't otherwise in use.  OTG devices may also start
 * remote wakeup even when hosts don't explicitly enable it.
 */
static inline int usb_gadget_wakeup(struct usb_gadget *gadget)
{
	if (!gadget->ops->wakeup)
		return -EOPNOTSUPP;
	return gadget->ops->wakeup(gadget);
}

/**
 * usb_gadget_set_selfpowered - sets the device selfpowered feature.
 * @gadget:the device being declared as self-powered
 *
 * this affects the device status reported by the hardware driver
 * to reflect that it now has a local power supply.
 *
 * returns zero on success, else negative errno.
 */
static inline int usb_gadget_set_selfpowered(struct usb_gadget *gadget)
{
	if (!gadget->ops->set_selfpowered)
		return -EOPNOTSUPP;
	return gadget->ops->set_selfpowered(gadget, 1);
}

/**
 * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
 * @gadget:the device being declared as bus-powered
 *
 * this affects the device status reported by the hardware driver.
 * some hardware may not support bus-powered operation, in which
 * case this feature's value can never change.
 *
 * returns zero on success, else negative errno.
 */
static inline int usb_gadget_clear_selfpowered(struct usb_gadget *gadget)
{
	if (!gadget->ops->set_selfpowered)
		return -EOPNOTSUPP;
	return gadget->ops->set_selfpowered(gadget, 0);
}

/**
 * usb_gadget_vbus_connect - Notify controller that VBUS is powered
 * @gadget:The device which now has VBUS power.
 * Context: can sleep
 *
 * This call is used by a driver for an external transceiver (or GPIO)
 * that detects a VBUS power session starting.  Common responses include
 * resuming the controller, activating the D+ (or D-) pullup to let the
 * host detect that a USB device is attached, and starting to draw power
 * (8mA or possibly more, especially after SET_CONFIGURATION).
 *
 * Returns zero on success, else negative errno.
 */
static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget)
{
	if (!gadget->ops->vbus_session)
		return -EOPNOTSUPP;
	return gadget->ops->vbus_session(gadget, 1);
}

/**
 * usb_gadget_vbus_draw - constrain controller's VBUS power usage
 * @gadget:The device whose VBUS usage is being described
 * @mA:How much current to draw, in milliAmperes.  This should be twice
 *	the value listed in the configuration descriptor bMaxPower field.
 *
 * This call is used by gadget drivers during SET_CONFIGURATION calls,
 * reporting how much power the device may consume.  For example, this
 * could affect how quickly batteries are recharged.
 *
 * Returns zero on success, else negative errno.
 */
static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
{
	if (!gadget->ops->vbus_draw)
		return -EOPNOTSUPP;
	return gadget->ops->vbus_draw(gadget, mA);
}

/**
 * usb_gadget_vbus_disconnect - notify controller about VBUS session end
 * @gadget:the device whose VBUS supply is being described
 * Context: can sleep
 *
 * This call is used by a driver for an external transceiver (or GPIO)
 * that detects a VBUS power session ending.  Common responses include
 * reversing everything done in usb_gadget_vbus_connect().
 *
 * Returns zero on success, else negative errno.
 */
static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
{
	if (!gadget->ops->vbus_session)
		return -EOPNOTSUPP;
	return gadget->ops->vbus_session(gadget, 0);
}

/**
 * usb_gadget_connect - software-controlled connect to USB host
 * @gadget:the peripheral being connected
 *
 * Enables the D+ (or potentially D-) pullup.  The host will start
 * enumerating this gadget when the pullup is active and a VBUS session
 * is active (the link is powered).  This pullup is always enabled unless
 * usb_gadget_disconnect() has been used to disable it.
 *
 * Returns zero on success, else negative errno.
 */
static inline int usb_gadget_connect(struct usb_gadget *gadget)
{
	if (!gadget->ops->pullup)
		return -EOPNOTSUPP;
	return gadget->ops->pullup(gadget, 1);
}

/**
 * usb_gadget_disconnect - software-controlled disconnect from USB host
 * @gadget:the peripheral being disconnected
 *
 * Disables the D+ (or potentially D-) pullup, which the host may see
 * as a disconnect (when a VBUS session is active).  Not all systems
 * support software pullup controls.
 *
 * This routine may be used during the gadget driver bind() call to prevent
 * the peripheral from ever being visible to the USB host, unless later
 * usb_gadget_connect() is called.  For example, user mode components may
 * need to be activated before the system can talk to hosts.
 *
 * Returns zero on success, else negative errno.
 */
static inline int usb_gadget_disconnect(struct usb_gadget *gadget)
{
	if (!gadget->ops->pullup)
		return -EOPNOTSUPP;
	return gadget->ops->pullup(gadget, 0);
}


/*-------------------------------------------------------------------------*/

/**
 * struct usb_gadget_driver - driver for usb 'slave' devices
 * @function: String describing the gadget's function
 * @max_speed: Highest speed the driver handles.
 * @setup: Invoked for ep0 control requests that aren't handled by
 *	the hardware level driver. Most calls must be handled by
 *	the gadget driver, including descriptor and configuration
 *	management.  The 16 bit members of the setup data are in
 *	USB byte order. Called in_interrupt; this may not sleep.  Driver
 *	queues a response to ep0, or returns negative to stall.
 * @disconnect: Invoked after all transfers have been stopped,
 *	when the host is disconnected.  May be called in_interrupt; this
 *	may not sleep.  Some devices can't detect disconnect, so this might
 *	not be called except as part of controller shutdown.
 * @bind: the driver's bind callback
 * @unbind: Invoked when the driver is unbound from a gadget,
 *	usually from rmmod (after a disconnect is reported).
 *	Called in a context that permits sleeping.
 * @suspend: Invoked on USB suspend.  May be called in_interrupt.
 * @resume: Invoked on USB resume.  May be called in_interrupt.
 * @driver: Driver model state for this driver.
 *
 * Devices are disabled till a gadget driver successfully bind()s, which
 * means the driver will handle setup() requests needed to enumerate (and
 * meet "chapter 9" requirements) then do some useful work.
 *
 * If gadget->is_otg is true, the gadget driver must provide an OTG
 * descriptor during enumeration, or else fail the bind() call.  In such
 * cases, no USB traffic may flow until both bind() returns without
 * having called usb_gadget_disconnect(), and the USB host stack has
 * initialized.
 *
 * Drivers use hardware-specific knowledge to configure the usb hardware.
 * endpoint addressing is only one of several hardware characteristics that
 * are in descriptors the ep0 implementation returns from setup() calls.
 *
 * Except for ep0 implementation, most driver code shouldn't need change to
 * run on top of different usb controllers.  It'll use endpoints set up by
 * that ep0 implementation.
 *
 * The usb controller driver handles a few standard usb requests.  Those
 * include set_address, and feature flags for devices, interfaces, and
 * endpoints (the get_status, set_feature, and clear_feature requests).
 *
 * Accordingly, the driver's setup() callback must always implement all
 * get_descriptor requests, returning at least a device descriptor and
 * a configuration descriptor.  Drivers must make sure the endpoint
 * descriptors match any hardware constraints. Some hardware also constrains
 * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
 *
 * The driver's setup() callback must also implement set_configuration,
 * and should also implement set_interface, get_configuration, and
 * get_interface.  Setting a configuration (or interface) is where
 * endpoints should be activated or (config 0) shut down.
 *
 * (Note that only the default control endpoint is supported.  Neither
 * hosts nor devices generally support control traffic except to ep0.)
 *
 * Most devices will ignore USB suspend/resume operations, and so will
 * not provide those callbacks.  However, some may need to change modes
 * when the host is not longer directing those activities.  For example,
 * local controls (buttons, dials, etc) may need to be re-enabled since
 * the (remote) host can't do that any longer; or an error state might
 * be cleared, to make the device behave identically whether or not
 * power is maintained.
 */
struct usb_gadget_driver {
	char			*function;
	enum usb_device_speed	max_speed;
	int			(*bind)(struct usb_gadget *gadget,
					struct usb_gadget_driver *driver);
	void			(*unbind)(struct usb_gadget *);
	int			(*setup)(struct usb_gadget *,
					const struct usb_ctrlrequest *);
	void			(*disconnect)(struct usb_gadget *);
	void			(*suspend)(struct usb_gadget *);
	void			(*resume)(struct usb_gadget *);

	/* FIXME support safe rmmod */
	struct device_driver	driver;
};



/*-------------------------------------------------------------------------*/

/* driver modules register and unregister, as usual.
 * these calls must be made in a context that can sleep.
 *
 * these will usually be implemented directly by the hardware-dependent
 * usb bus interface driver, which will only support a single driver.
 */

/**
 * usb_gadget_probe_driver - probe a gadget driver
 * @driver: the driver being registered
 * Context: can sleep
 *
 * Call this in your gadget driver's module initialization function,
 * to tell the underlying usb controller driver about your driver.
 * The @bind() function will be called to bind it to a gadget before this
 * registration call returns.  It's expected that the @bind() function will
 * be in init sections.
 */
int usb_gadget_probe_driver(struct usb_gadget_driver *driver);

/**
 * usb_gadget_unregister_driver - unregister a gadget driver
 * @driver:the driver being unregistered
 * Context: can sleep
 *
 * Call this in your gadget driver's module cleanup function,
 * to tell the underlying usb controller that your driver is
 * going away.  If the controller is connected to a USB host,
 * it will first disconnect().  The driver is also requested
 * to unbind() and clean up any device state, before this procedure
 * finally returns.  It's expected that the unbind() functions
 * will in in exit sections, so may not be linked in some kernels.
 */
int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);

extern int usb_add_gadget_udc_release(struct device *parent,
		struct usb_gadget *gadget, void (*release)(struct device *dev));
extern int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget);
extern void usb_del_gadget_udc(struct usb_gadget *gadget);
extern int udc_attach_driver(const char *name,
		struct usb_gadget_driver *driver);

/*-------------------------------------------------------------------------*/

/* utility to simplify dealing with string descriptors */

/**
 * struct usb_string - wraps a C string and its USB id
 * @id:the (nonzero) ID for this string
 * @s:the string, in UTF-8 encoding
 *
 * If you're using usb_gadget_get_string(), use this to wrap a string
 * together with its ID.
 */
struct usb_string {
	u8			id;
	const char		*s;
};

/**
 * struct usb_gadget_strings - a set of USB strings in a given language
 * @language:identifies the strings' language (0x0409 for en-us)
 * @strings:array of strings with their ids
 *
 * If you're using usb_gadget_get_string(), use this to wrap all the
 * strings for a given language.
 */
struct usb_gadget_strings {
	u16			language;	/* 0x0409 for en-us */
	struct usb_string	*strings;
};

struct usb_gadget_string_container {
	struct list_head        list;
	u8                      *stash[0];
};

/* put descriptor for string with that id into buf (buflen >= 256) */
int usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf);

/*-------------------------------------------------------------------------*/

/* utility to simplify managing config descriptors */

/* write vector of descriptors into buffer */
int usb_descriptor_fillbuf(void *, unsigned,
		const struct usb_descriptor_header **);

/* build config descriptor from single descriptor vector */
int usb_gadget_config_buf(const struct usb_config_descriptor *config,
	void *buf, unsigned buflen, const struct usb_descriptor_header **desc);

/* copy a NULL-terminated vector of descriptors */
struct usb_descriptor_header **usb_copy_descriptors(
		struct usb_descriptor_header **);

/**
 * usb_free_descriptors - free descriptors returned by usb_copy_descriptors()
 * @v: vector of descriptors
 */
static inline void usb_free_descriptors(struct usb_descriptor_header **v)
{
	kfree(v);
}

struct usb_function;
int usb_assign_descriptors(struct usb_function *f,
		struct usb_descriptor_header **fs,
		struct usb_descriptor_header **hs,
		struct usb_descriptor_header **ss);
void usb_free_all_descriptors(struct usb_function *f);

/*-------------------------------------------------------------------------*/

/* utility to simplify map/unmap of usb_requests to/from DMA */

extern int usb_gadget_map_request(struct usb_gadget *gadget,
		struct usb_request *req, int is_in);

extern void usb_gadget_unmap_request(struct usb_gadget *gadget,
		struct usb_request *req, int is_in);

/*-------------------------------------------------------------------------*/

/* utility to set gadget state properly */

extern void usb_gadget_set_state(struct usb_gadget *gadget,
		enum usb_device_state state);

/*-------------------------------------------------------------------------*/

/* utility wrapping a simple endpoint selection policy */

extern struct usb_ep *usb_ep_autoconfig(struct usb_gadget *,
			struct usb_endpoint_descriptor *);


extern struct usb_ep *usb_ep_autoconfig_ss(struct usb_gadget *,
			struct usb_endpoint_descriptor *,
			struct usb_ss_ep_comp_descriptor *);

extern void usb_ep_autoconfig_reset(struct usb_gadget *);

#endif /* __LINUX_USB_GADGET_H */
OpenPOWER on IntegriCloud