aboutsummaryrefslogtreecommitdiffstats
path: root/sys/dev/usb/usb_hid.c
blob: dc0ce99facc478667ff7873755ae98fb46d4596f (plain) (blame)
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
/* $FreeBSD$ */
/*	$NetBSD: hid.c,v 1.17 2001/11/13 06:24:53 lukem Exp $	*/
/*-
 * Copyright (c) 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Lennart Augustsson (lennart@augustsson.net) at
 * Carlstedt Research & Technology.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef USB_GLOBAL_INCLUDE_FILE
#include USB_GLOBAL_INCLUDE_FILE
#else
#include <sys/stdint.h>
#include <sys/stddef.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#include <sys/unistd.h>
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/priv.h>

#include <dev/usb/usb.h>
#include <dev/usb/usbdi.h>
#include <dev/usb/usbdi_util.h>
#include <dev/usb/usbhid.h>

#define	USB_DEBUG_VAR usb_debug

#include <dev/usb/usb_core.h>
#include <dev/usb/usb_debug.h>
#include <dev/usb/usb_process.h>
#include <dev/usb/usb_device.h>
#include <dev/usb/usb_request.h>
#endif			/* USB_GLOBAL_INCLUDE_FILE */

static void hid_clear_local(struct hid_item *);
static uint8_t hid_get_byte(struct hid_data *s, const uint16_t wSize);

#define	MAXUSAGE 64
#define	MAXPUSH 4
#define	MAXID 16

struct hid_pos_data {
	int32_t rid;
	uint32_t pos;
};

struct hid_data {
	const uint8_t *start;
	const uint8_t *end;
	const uint8_t *p;
	struct hid_item cur[MAXPUSH];
	struct hid_pos_data last_pos[MAXID];
	int32_t	usages_min[MAXUSAGE];
	int32_t	usages_max[MAXUSAGE];
	int32_t usage_last;	/* last seen usage */
	uint32_t loc_size;	/* last seen size */
	uint32_t loc_count;	/* last seen count */
	uint8_t	kindset;	/* we have 5 kinds so 8 bits are enough */
	uint8_t	pushlevel;	/* current pushlevel */
	uint8_t	ncount;		/* end usage item count */
	uint8_t icount;		/* current usage item count */
	uint8_t	nusage;		/* end "usages_min/max" index */
	uint8_t	iusage;		/* current "usages_min/max" index */
	uint8_t ousage;		/* current "usages_min/max" offset */
	uint8_t	susage;		/* usage set flags */
};

/*------------------------------------------------------------------------*
 *	hid_clear_local
 *------------------------------------------------------------------------*/
static void
hid_clear_local(struct hid_item *c)
{

	c->loc.count = 0;
	c->loc.size = 0;
	c->usage = 0;
	c->usage_minimum = 0;
	c->usage_maximum = 0;
	c->designator_index = 0;
	c->designator_minimum = 0;
	c->designator_maximum = 0;
	c->string_index = 0;
	c->string_minimum = 0;
	c->string_maximum = 0;
	c->set_delimiter = 0;
}

static void
hid_switch_rid(struct hid_data *s, struct hid_item *c, int32_t next_rID)
{
	uint8_t i;

	/* check for same report ID - optimise */

	if (c->report_ID == next_rID)
		return;

	/* save current position for current rID */

	if (c->report_ID == 0) {
		i = 0;
	} else {
		for (i = 1; i != MAXID; i++) {
			if (s->last_pos[i].rid == c->report_ID)
				break;
			if (s->last_pos[i].rid == 0)
				break;
		}
	}
	if (i != MAXID) {
		s->last_pos[i].rid = c->report_ID;
		s->last_pos[i].pos = c->loc.pos;
	}

	/* store next report ID */

	c->report_ID = next_rID;

	/* lookup last position for next rID */

	if (next_rID == 0) {
		i = 0;
	} else {
		for (i = 1; i != MAXID; i++) {
			if (s->last_pos[i].rid == next_rID)
				break;
			if (s->last_pos[i].rid == 0)
				break;
		}
	}
	if (i != MAXID) {
		s->last_pos[i].rid = next_rID;
		c->loc.pos = s->last_pos[i].pos;
	} else {
		DPRINTF("Out of RID entries, position is set to zero!\n");
		c->loc.pos = 0;
	}
}

/*------------------------------------------------------------------------*
 *	hid_start_parse
 *------------------------------------------------------------------------*/
struct hid_data *
hid_start_parse(const void *d, usb_size_t len, int kindset)
{
	struct hid_data *s;

	if ((kindset-1) & kindset) {
		DPRINTFN(0, "Only one bit can be "
		    "set in the kindset\n");
		return (NULL);
	}

	s = malloc(sizeof *s, M_TEMP, M_WAITOK | M_ZERO);
	s->start = s->p = d;
	s->end = ((const uint8_t *)d) + len;
	s->kindset = kindset;
	return (s);
}

/*------------------------------------------------------------------------*
 *	hid_end_parse
 *------------------------------------------------------------------------*/
void
hid_end_parse(struct hid_data *s)
{
	if (s == NULL)
		return;

	free(s, M_TEMP);
}

/*------------------------------------------------------------------------*
 *	get byte from HID descriptor
 *------------------------------------------------------------------------*/
static uint8_t
hid_get_byte(struct hid_data *s, const uint16_t wSize)
{
	const uint8_t *ptr;
	uint8_t retval;

	ptr = s->p;

	/* check if end is reached */
	if (ptr == s->end)
		return (0);

	/* read out a byte */
	retval = *ptr;

	/* check if data pointer can be advanced by "wSize" bytes */
	if ((s->end - ptr) < wSize)
		ptr = s->end;
	else
		ptr += wSize;

	/* update pointer */
	s->p = ptr;

	return (retval);
}

/*------------------------------------------------------------------------*
 *	hid_get_item
 *------------------------------------------------------------------------*/
int
hid_get_item(struct hid_data *s, struct hid_item *h)
{
	struct hid_item *c;
	unsigned int bTag, bType, bSize;
	uint32_t oldpos;
	int32_t mask;
	int32_t dval;

	if (s == NULL)
		return (0);

	c = &s->cur[s->pushlevel];

 top:
	/* check if there is an array of items */
	if (s->icount < s->ncount) {
		/* get current usage */
		if (s->iusage < s->nusage) {
			dval = s->usages_min[s->iusage] + s->ousage;
			c->usage = dval;
			s->usage_last = dval;
			if (dval == s->usages_max[s->iusage]) {
				s->iusage ++;
				s->ousage = 0;
			} else {
				s->ousage ++;
			}
		} else {
			DPRINTFN(1, "Using last usage\n");
			dval = s->usage_last;
		}
		s->icount ++;
		/* 
		 * Only copy HID item, increment position and return
		 * if correct kindset!
		 */
		if (s->kindset & (1 << c->kind)) {
			*h = *c;
			DPRINTFN(1, "%u,%u,%u\n", h->loc.pos,
			    h->loc.size, h->loc.count);
			c->loc.pos += c->loc.size * c->loc.count;
			return (1);
		}
	}

	/* reset state variables */
	s->icount = 0;
	s->ncount = 0;
	s->iusage = 0;
	s->nusage = 0;
	s->susage = 0;
	s->ousage = 0;
	hid_clear_local(c);

	/* get next item */
	while (s->p != s->end) {

		bSize = hid_get_byte(s, 1);
		if (bSize == 0xfe) {
			/* long item */
			bSize = hid_get_byte(s, 1);
			bSize |= hid_get_byte(s, 1) << 8;
			bTag = hid_get_byte(s, 1);
			bType = 0xff;	/* XXX what should it be */
		} else {
			/* short item */
			bTag = bSize >> 4;
			bType = (bSize >> 2) & 3;
			bSize &= 3;
			if (bSize == 3)
				bSize = 4;
		}
		switch (bSize) {
		case 0:
			dval = 0;
			mask = 0;
			break;
		case 1:
			dval = (int8_t)hid_get_byte(s, 1);
			mask = 0xFF;
			break;
		case 2:
			dval = hid_get_byte(s, 1);
			dval |= hid_get_byte(s, 1) << 8;
			dval = (int16_t)dval;
			mask = 0xFFFF;
			break;
		case 4:
			dval = hid_get_byte(s, 1);
			dval |= hid_get_byte(s, 1) << 8;
			dval |= hid_get_byte(s, 1) << 16;
			dval |= hid_get_byte(s, 1) << 24;
			mask = 0xFFFFFFFF;
			break;
		default:
			dval = hid_get_byte(s, bSize);
			DPRINTFN(0, "bad length %u (data=0x%02x)\n",
			    bSize, dval);
			continue;
		}

		switch (bType) {
		case 0:		/* Main */
			switch (bTag) {
			case 8:	/* Input */
				c->kind = hid_input;
				c->flags = dval;
		ret:
				c->loc.count = s->loc_count;
				c->loc.size = s->loc_size;

				if (c->flags & HIO_VARIABLE) {
					/* range check usage count */
					if (c->loc.count > 255) {
						DPRINTFN(0, "Number of "
						    "items(%u) truncated to 255\n",
						    (unsigned)(c->loc.count));
						s->ncount = 255;
					} else
						s->ncount = c->loc.count;

					/* 
					 * The "top" loop will return
					 * one and one item:
					 */
					c->loc.count = 1;
				} else {
					s->ncount = 1;
				}
				goto top;

			case 9:	/* Output */
				c->kind = hid_output;
				c->flags = dval;
				goto ret;
			case 10:	/* Collection */
				c->kind = hid_collection;
				c->collection = dval;
				c->collevel++;
				c->usage = s->usage_last;
				*h = *c;
				return (1);
			case 11:	/* Feature */
				c->kind = hid_feature;
				c->flags = dval;
				goto ret;
			case 12:	/* End collection */
				c->kind = hid_endcollection;
				if (c->collevel == 0) {
					DPRINTFN(0, "invalid end collection\n");
					return (0);
				}
				c->collevel--;
				*h = *c;
				return (1);
			default:
				DPRINTFN(0, "Main bTag=%d\n", bTag);
				break;
			}
			break;
		case 1:		/* Global */
			switch (bTag) {
			case 0:
				c->_usage_page = dval << 16;
				break;
			case 1:
				c->logical_minimum = dval;
				break;
			case 2:
				c->logical_maximum = dval;
				break;
			case 3:
				c->physical_minimum = dval;
				break;
			case 4:
				c->physical_maximum = dval;
				break;
			case 5:
				c->unit_exponent = dval;
				break;
			case 6:
				c->unit = dval;
				break;
			case 7:
				/* mask because value is unsigned */
				s->loc_size = dval & mask;
				break;
			case 8:
				hid_switch_rid(s, c, dval & mask);
				break;
			case 9:
				/* mask because value is unsigned */
				s->loc_count = dval & mask;
				break;
			case 10:	/* Push */
				s->pushlevel ++;
				if (s->pushlevel < MAXPUSH) {
					s->cur[s->pushlevel] = *c;
					/* store size and count */
					c->loc.size = s->loc_size;
					c->loc.count = s->loc_count;
					/* update current item pointer */
					c = &s->cur[s->pushlevel];
				} else {
					DPRINTFN(0, "Cannot push "
					    "item @ %d\n", s->pushlevel);
				}
				break;
			case 11:	/* Pop */
				s->pushlevel --;
				if (s->pushlevel < MAXPUSH) {
					/* preserve position */
					oldpos = c->loc.pos;
					c = &s->cur[s->pushlevel];
					/* restore size and count */
					s->loc_size = c->loc.size;
					s->loc_count = c->loc.count;
					/* set default item location */
					c->loc.pos = oldpos;
					c->loc.size = 0;
					c->loc.count = 0;
				} else {
					DPRINTFN(0, "Cannot pop "
					    "item @ %d\n", s->pushlevel);
				}
				break;
			default:
				DPRINTFN(0, "Global bTag=%d\n", bTag);
				break;
			}
			break;
		case 2:		/* Local */
			switch (bTag) {
			case 0:
				if (bSize != 4)
					dval = (dval & mask) | c->_usage_page;

				/* set last usage, in case of a collection */
				s->usage_last = dval;

				if (s->nusage < MAXUSAGE) {
					s->usages_min[s->nusage] = dval;
					s->usages_max[s->nusage] = dval;
					s->nusage ++;
				} else {
					DPRINTFN(0, "max usage reached\n");
				}

				/* clear any pending usage sets */
				s->susage = 0;
				break;
			case 1:
				s->susage |= 1;

				if (bSize != 4)
					dval = (dval & mask) | c->_usage_page;
				c->usage_minimum = dval;

				goto check_set;
			case 2:
				s->susage |= 2;

				if (bSize != 4)
					dval = (dval & mask) | c->_usage_page;
				c->usage_maximum = dval;

			check_set:
				if (s->susage != 3)
					break;

				/* sanity check */
				if ((s->nusage < MAXUSAGE) &&
				    (c->usage_minimum <= c->usage_maximum)) {
					/* add usage range */
					s->usages_min[s->nusage] = 
					    c->usage_minimum;
					s->usages_max[s->nusage] = 
					    c->usage_maximum;
					s->nusage ++;
				} else {
					DPRINTFN(0, "Usage set dropped\n");
				}
				s->susage = 0;
				break;
			case 3:
				c->designator_index = dval;
				break;
			case 4:
				c->designator_minimum = dval;
				break;
			case 5:
				c->designator_maximum = dval;
				break;
			case 7:
				c->string_index = dval;
				break;
			case 8:
				c->string_minimum = dval;
				break;
			case 9:
				c->string_maximum = dval;
				break;
			case 10:
				c->set_delimiter = dval;
				break;
			default:
				DPRINTFN(0, "Local bTag=%d\n", bTag);
				break;
			}
			break;
		default:
			DPRINTFN(0, "default bType=%d\n", bType);
			break;
		}
	}
	return (0);
}

/*------------------------------------------------------------------------*
 *	hid_report_size
 *------------------------------------------------------------------------*/
int
hid_report_size(const void *buf, usb_size_t len, enum hid_kind k, uint8_t *id)
{
	struct hid_data *d;
	struct hid_item h;
	uint32_t temp;
	uint32_t hpos;
	uint32_t lpos;
	uint8_t any_id;

	any_id = 0;
	hpos = 0;
	lpos = 0xFFFFFFFF;

	for (d = hid_start_parse(buf, len, 1 << k); hid_get_item(d, &h);) {
		if (h.kind == k) {
			/* check for ID-byte presense */
			if ((h.report_ID != 0) && !any_id) {
				if (id != NULL)
					*id = h.report_ID;
				any_id = 1;
			}
			/* compute minimum */
			if (lpos > h.loc.pos)
				lpos = h.loc.pos;
			/* compute end position */
			temp = h.loc.pos + (h.loc.size * h.loc.count);
			/* compute maximum */
			if (hpos < temp)
				hpos = temp;
		}
	}
	hid_end_parse(d);

	/* safety check - can happen in case of currupt descriptors */
	if (lpos > hpos)
		temp = 0;
	else
		temp = hpos - lpos;

	/* check for ID byte */
	if (any_id)
		temp += 8;
	else if (id != NULL)
		*id = 0;

	/* return length in bytes rounded up */
	return ((temp + 7) / 8);
}

/*------------------------------------------------------------------------*
 *	hid_locate
 *------------------------------------------------------------------------*/
int
hid_locate(const void *desc, usb_size_t size, int32_t u, enum hid_kind k,
    uint8_t index, struct hid_location *loc, uint32_t *flags, uint8_t *id)
{
	struct hid_data *d;
	struct hid_item h;

	for (d = hid_start_parse(desc, size, 1 << k); hid_get_item(d, &h);) {
		if (h.kind == k && !(h.flags & HIO_CONST) && h.usage == u) {
			if (index--)
				continue;
			if (loc != NULL)
				*loc = h.loc;
			if (flags != NULL)
				*flags = h.flags;
			if (id != NULL)
				*id = h.report_ID;
			hid_end_parse(d);
			return (1);
		}
	}
	if (loc != NULL)
		loc->size = 0;
	if (flags != NULL)
		*flags = 0;
	if (id != NULL)
		*id = 0;
	hid_end_parse(d);
	return (0);
}

/*------------------------------------------------------------------------*
 *	hid_get_data
 *------------------------------------------------------------------------*/
static uint32_t
hid_get_data_sub(const uint8_t *buf, usb_size_t len, struct hid_location *loc,
    int is_signed)
{
	uint32_t hpos = loc->pos;
	uint32_t hsize = loc->size;
	uint32_t data;
	uint32_t rpos;
	uint8_t n;

	DPRINTFN(11, "hid_get_data: loc %d/%d\n", hpos, hsize);

	/* Range check and limit */
	if (hsize == 0)
		return (0);
	if (hsize > 32)
		hsize = 32;

	/* Get data in a safe way */	
	data = 0;
	rpos = (hpos / 8);
	n = (hsize + 7) / 8;
	rpos += n;
	while (n--) {
		rpos--;
		if (rpos < len)
			data |= buf[rpos] << (8 * n);
	}

	/* Correctly shift down data */
	data = (data >> (hpos % 8));
	n = 32 - hsize;

	/* Mask and sign extend in one */
	if (is_signed != 0)
		data = (int32_t)((int32_t)data << n) >> n;
	else
		data = (uint32_t)((uint32_t)data << n) >> n;

	DPRINTFN(11, "hid_get_data: loc %d/%d = %lu\n",
	    loc->pos, loc->size, (long)data);
	return (data);
}

int32_t
hid_get_data(const uint8_t *buf, usb_size_t len, struct hid_location *loc)
{
	return (hid_get_data_sub(buf, len, loc, 1));
}

uint32_t
hid_get_data_unsigned(const uint8_t *buf, usb_size_t len, struct hid_location *loc)
{
        return (hid_get_data_sub(buf, len, loc, 0));
}

/*------------------------------------------------------------------------*
 *	hid_put_data
 *------------------------------------------------------------------------*/
void
hid_put_data_unsigned(uint8_t *buf, usb_size_t len,
    struct hid_location *loc, unsigned int value)
{
	uint32_t hpos = loc->pos;
	uint32_t hsize = loc->size;
	uint64_t data;
	uint64_t mask;
	uint32_t rpos;
	uint8_t n;

	DPRINTFN(11, "hid_put_data: loc %d/%d = %u\n", hpos, hsize, value);

	/* Range check and limit */
	if (hsize == 0)
		return;
	if (hsize > 32)
		hsize = 32;

	/* Put data in a safe way */	
	rpos = (hpos / 8);
	n = (hsize + 7) / 8;
	data = ((uint64_t)value) << (hpos % 8);
	mask = ((1ULL << hsize) - 1ULL) << (hpos % 8);
	rpos += n;
	while (n--) {
		rpos--;
		if (rpos < len) {
			buf[rpos] &= ~(mask >> (8 * n));
			buf[rpos] |= (data >> (8 * n));
		}
	}
}

/*------------------------------------------------------------------------*
 *	hid_is_collection
 *------------------------------------------------------------------------*/
int
hid_is_collection(const void *desc, usb_size_t size, int32_t usage)
{
	struct hid_data *hd;
	struct hid_item hi;
	int err;

	hd = hid_start_parse(desc, size, hid_input);
	if (hd == NULL)
		return (0);

	while ((err = hid_get_item(hd, &hi))) {
		 if (hi.kind == hid_collection &&
		     hi.usage == usage)
			break;
	}
	hid_end_parse(hd);
	return (err);
}

/*------------------------------------------------------------------------*
 *	hid_get_descriptor_from_usb
 *
 * This function will search for a HID descriptor between two USB
 * interface descriptors.
 *
 * Return values:
 * NULL: No more HID descriptors.
 * Else: Pointer to HID descriptor.
 *------------------------------------------------------------------------*/
struct usb_hid_descriptor *
hid_get_descriptor_from_usb(struct usb_config_descriptor *cd,
    struct usb_interface_descriptor *id)
{
	struct usb_descriptor *desc = (void *)id;

	if (desc == NULL) {
		return (NULL);
	}
	while ((desc = usb_desc_foreach(cd, desc))) {
		if ((desc->bDescriptorType == UDESC_HID) &&
		    (desc->bLength >= USB_HID_DESCRIPTOR_SIZE(0))) {
			return (void *)desc;
		}
		if (desc->bDescriptorType == UDESC_INTERFACE) {
			break;
		}
	}
	return (NULL);
}

/*------------------------------------------------------------------------*
 *	usbd_req_get_hid_desc
 *
 * This function will read out an USB report descriptor from the USB
 * device.
 *
 * Return values:
 * NULL: Failure.
 * Else: Success. The pointer should eventually be passed to free().
 *------------------------------------------------------------------------*/
usb_error_t
usbd_req_get_hid_desc(struct usb_device *udev, struct mtx *mtx,
    void **descp, uint16_t *sizep,
    struct malloc_type *mem, uint8_t iface_index)
{
	struct usb_interface *iface = usbd_get_iface(udev, iface_index);
	struct usb_hid_descriptor *hid;
	usb_error_t err;

	if ((iface == NULL) || (iface->idesc == NULL)) {
		return (USB_ERR_INVAL);
	}
	hid = hid_get_descriptor_from_usb
	    (usbd_get_config_descriptor(udev), iface->idesc);

	if (hid == NULL) {
		return (USB_ERR_IOERROR);
	}
	*sizep = UGETW(hid->descrs[0].wDescriptorLength);
	if (*sizep == 0) {
		return (USB_ERR_IOERROR);
	}
	if (mtx)
		mtx_unlock(mtx);

	*descp = malloc(*sizep, mem, M_ZERO | M_WAITOK);

	if (mtx)
		mtx_lock(mtx);

	if (*descp == NULL) {
		return (USB_ERR_NOMEM);
	}
	err = usbd_req_get_report_descriptor
	    (udev, mtx, *descp, *sizep, iface_index);

	if (err) {
		free(*descp, mem);
		*descp = NULL;
		return (err);
	}
	return (USB_ERR_NORMAL_COMPLETION);
}

/*------------------------------------------------------------------------*
 *	hid_is_mouse
 *
 * This function will decide if a USB descriptor belongs to a USB mouse.
 *
 * Return values:
 * Zero: Not a USB mouse.
 * Else: Is a USB mouse.
 *------------------------------------------------------------------------*/
int
hid_is_mouse(const void *d_ptr, uint16_t d_len)
{
	struct hid_data *hd;
	struct hid_item hi;
	int mdepth;
	int found;

	hd = hid_start_parse(d_ptr, d_len, 1 << hid_input);
	if (hd == NULL)
		return (0);

	mdepth = 0;
	found = 0;

	while (hid_get_item(hd, &hi)) {
		switch (hi.kind) {
		case hid_collection:
			if (mdepth != 0)
				mdepth++;
			else if (hi.collection == 1 &&
			     hi.usage ==
			      HID_USAGE2(HUP_GENERIC_DESKTOP, HUG_MOUSE))
				mdepth++;
			break;
		case hid_endcollection:
			if (mdepth != 0)
				mdepth--;
			break;
		case hid_input:
			if (mdepth == 0)
				break;
			if (hi.usage ==
			     HID_USAGE2(HUP_GENERIC_DESKTOP, HUG_X) &&
			    (hi.flags & (HIO_CONST|HIO_RELATIVE)) == HIO_RELATIVE)
				found++;
			if (hi.usage ==
			     HID_USAGE2(HUP_GENERIC_DESKTOP, HUG_Y) &&
			    (hi.flags & (HIO_CONST|HIO_RELATIVE)) == HIO_RELATIVE)
				found++;
			break;
		default:
			break;
		}
	}
	hid_end_parse(hd);
	return (found);
}

/*------------------------------------------------------------------------*
 *	hid_is_keyboard
 *
 * This function will decide if a USB descriptor belongs to a USB keyboard.
 *
 * Return values:
 * Zero: Not a USB keyboard.
 * Else: Is a USB keyboard.
 *------------------------------------------------------------------------*/
int
hid_is_keyboard(const void *d_ptr, uint16_t d_len)
{
	if (hid_is_collection(d_ptr, d_len,
	    HID_USAGE2(HUP_GENERIC_DESKTOP, HUG_KEYBOARD)))
		return (1);
	return (0);
}