summaryrefslogtreecommitdiff
path: root/drivers/usb/gadget/composite.c
blob: 96413a240fdfa786a3e18a2db5ff0d99e37fb4fb (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
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
/*
 * composite.c - infrastructure for Composite USB Gadgets
 *
 * Copyright (C) 2006-2008 David Brownell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/* #define VERBOSE_DEBUG */

#include <linux/kallsyms.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/utsname.h>

#include <linux/usb/composite.h>


/*
 * The code in this file is utility code, used to build a gadget driver
 * from one or more "function" drivers, one or more "configuration"
 * objects, and a "usb_composite_driver" by gluing them together along
 * with the relevant device-wide data.
 */

/* big enough to hold our biggest descriptor */
#define USB_BUFSIZ	1024

static struct usb_composite_driver *composite;
static int (*composite_gadget_bind)(struct usb_composite_dev *cdev);

/* Some systems will need runtime overrides for the  product identifers
 * published in the device descriptor, either numbers or strings or both.
 * String parameters are in UTF-8 (superset of ASCII's 7 bit characters).
 */

static ushort idVendor;
module_param(idVendor, ushort, 0);
MODULE_PARM_DESC(idVendor, "USB Vendor ID");

static ushort idProduct;
module_param(idProduct, ushort, 0);
MODULE_PARM_DESC(idProduct, "USB Product ID");

static ushort bcdDevice;
module_param(bcdDevice, ushort, 0);
MODULE_PARM_DESC(bcdDevice, "USB Device version (BCD)");

static char *iManufacturer;
module_param(iManufacturer, charp, 0);
MODULE_PARM_DESC(iManufacturer, "USB Manufacturer string");

static char *iProduct;
module_param(iProduct, charp, 0);
MODULE_PARM_DESC(iProduct, "USB Product string");

static char *iSerialNumber;
module_param(iSerialNumber, charp, 0);
MODULE_PARM_DESC(iSerialNumber, "SerialNumber string");

static char composite_manufacturer[50];

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

/**
 * usb_add_function() - add a function to a configuration
 * @config: the configuration
 * @function: the function being added
 * Context: single threaded during gadget setup
 *
 * After initialization, each configuration must have one or more
 * functions added to it.  Adding a function involves calling its @bind()
 * method to allocate resources such as interface and string identifiers
 * and endpoints.
 *
 * This function returns the value of the function's bind(), which is
 * zero for success else a negative errno value.
 */
int usb_add_function(struct usb_configuration *config,
		struct usb_function *function)
{
	int	value = -EINVAL;

	DBG(config->cdev, "adding '%s'/%p to config '%s'/%p\n",
			function->name, function,
			config->label, config);

	if (!function->set_alt || !function->disable)
		goto done;

	function->config = config;
	list_add_tail(&function->list, &config->functions);

	/* REVISIT *require* function->bind? */
	if (function->bind) {
		value = function->bind(config, function);
		if (value < 0) {
			list_del(&function->list);
			function->config = NULL;
		}
	} else
		value = 0;

	/* We allow configurations that don't work at both speeds.
	 * If we run into a lowspeed Linux system, treat it the same
	 * as full speed ... it's the function drivers that will need
	 * to avoid bulk and ISO transfers.
	 */
	if (!config->fullspeed && function->descriptors)
		config->fullspeed = true;
	if (!config->highspeed && function->hs_descriptors)
		config->highspeed = true;

done:
	if (value)
		DBG(config->cdev, "adding '%s'/%p --> %d\n",
				function->name, function, value);
	return value;
}

/**
 * usb_function_deactivate - prevent function and gadget enumeration
 * @function: the function that isn't yet ready to respond
 *
 * Blocks response of the gadget driver to host enumeration by
 * preventing the data line pullup from being activated.  This is
 * normally called during @bind() processing to change from the
 * initial "ready to respond" state, or when a required resource
 * becomes available.
 *
 * For example, drivers that serve as a passthrough to a userspace
 * daemon can block enumeration unless that daemon (such as an OBEX,
 * MTP, or print server) is ready to handle host requests.
 *
 * Not all systems support software control of their USB peripheral
 * data pullups.
 *
 * Returns zero on success, else negative errno.
 */
int usb_function_deactivate(struct usb_function *function)
{
	struct usb_composite_dev	*cdev = function->config->cdev;
	unsigned long			flags;
	int				status = 0;

	spin_lock_irqsave(&cdev->lock, flags);

	if (cdev->deactivations == 0)
		status = usb_gadget_disconnect(cdev->gadget);
	if (status == 0)
		cdev->deactivations++;

	spin_unlock_irqrestore(&cdev->lock, flags);
	return status;
}

/**
 * usb_function_activate - allow function and gadget enumeration
 * @function: function on which usb_function_activate() was called
 *
 * Reverses effect of usb_function_deactivate().  If no more functions
 * are delaying their activation, the gadget driver will respond to
 * host enumeration procedures.
 *
 * Returns zero on success, else negative errno.
 */
int usb_function_activate(struct usb_function *function)
{
	struct usb_composite_dev	*cdev = function->config->cdev;
	int				status = 0;

	spin_lock(&cdev->lock);

	if (WARN_ON(cdev->deactivations == 0))
		status = -EINVAL;
	else {
		cdev->deactivations--;
		if (cdev->deactivations == 0)
			status = usb_gadget_connect(cdev->gadget);
	}

	spin_unlock(&cdev->lock);
	return status;
}

/**
 * usb_interface_id() - allocate an unused interface ID
 * @config: configuration associated with the interface
 * @function: function handling the interface
 * Context: single threaded during gadget setup
 *
 * usb_interface_id() is called from usb_function.bind() callbacks to
 * allocate new interface IDs.  The function driver will then store that
 * ID in interface, association, CDC union, and other descriptors.  It
 * will also handle any control requests targetted at that interface,
 * particularly changing its altsetting via set_alt().  There may
 * also be class-specific or vendor-specific requests to handle.
 *
 * All interface identifier should be allocated using this routine, to
 * ensure that for example different functions don't wrongly assign
 * different meanings to the same identifier.  Note that since interface
 * identifers are configuration-specific, functions used in more than
 * one configuration (or more than once in a given configuration) need
 * multiple versions of the relevant descriptors.
 *
 * Returns the interface ID which was allocated; or -ENODEV if no
 * more interface IDs can be allocated.
 */
int usb_interface_id(struct usb_configuration *config,
		struct usb_function *function)
{
	unsigned id = config->next_interface_id;

	if (id < MAX_CONFIG_INTERFACES) {
		config->interface[id] = function;
		config->next_interface_id = id + 1;
		return id;
	}
	return -ENODEV;
}

static int config_buf(struct usb_configuration *config,
		enum usb_device_speed speed, void *buf, u8 type)
{
	struct usb_config_descriptor	*c = buf;
	void				*next = buf + USB_DT_CONFIG_SIZE;
	int				len = USB_BUFSIZ - USB_DT_CONFIG_SIZE;
	struct usb_function		*f;
	int				status;

	/* write the config descriptor */
	c = buf;
	c->bLength = USB_DT_CONFIG_SIZE;
	c->bDescriptorType = type;
	/* wTotalLength is written later */
	c->bNumInterfaces = config->next_interface_id;
	c->bConfigurationValue = config->bConfigurationValue;
	c->iConfiguration = config->iConfiguration;
	c->bmAttributes = USB_CONFIG_ATT_ONE | config->bmAttributes;
	c->bMaxPower = config->bMaxPower ? : (CONFIG_USB_GADGET_VBUS_DRAW / 2);

	/* There may be e.g. OTG descriptors */
	if (config->descriptors) {
		status = usb_descriptor_fillbuf(next, len,
				config->descriptors);
		if (status < 0)
			return status;
		len -= status;
		next += status;
	}

	/* add each function's descriptors */
	list_for_each_entry(f, &config->functions, list) {
		struct usb_descriptor_header **descriptors;

		if (speed == USB_SPEED_HIGH)
			descriptors = f->hs_descriptors;
		else
			descriptors = f->descriptors;
		if (!descriptors)
			continue;
		status = usb_descriptor_fillbuf(next, len,
			(const struct usb_descriptor_header **) descriptors);
		if (status < 0)
			return status;
		len -= status;
		next += status;
	}

	len = next - buf;
	c->wTotalLength = cpu_to_le16(len);
	return len;
}

static int config_desc(struct usb_composite_dev *cdev, unsigned w_value)
{
	struct usb_gadget		*gadget = cdev->gadget;
	struct usb_configuration	*c;
	u8				type = w_value >> 8;
	enum usb_device_speed		speed = USB_SPEED_UNKNOWN;

	if (gadget_is_dualspeed(gadget)) {
		int			hs = 0;

		if (gadget->speed == USB_SPEED_HIGH)
			hs = 1;
		if (type == USB_DT_OTHER_SPEED_CONFIG)
			hs = !hs;
		if (hs)
			speed = USB_SPEED_HIGH;

	}

	/* This is a lookup by config *INDEX* */
	w_value &= 0xff;
	list_for_each_entry(c, &cdev->configs, list) {
		/* ignore configs that won't work at this speed */
		if (speed == USB_SPEED_HIGH) {
			if (!c->highspeed)
				continue;
		} else {
			if (!c->fullspeed)
				continue;
		}
		if (w_value == 0)
			return config_buf(c, speed, cdev->req->buf, type);
		w_value--;
	}
	return -EINVAL;
}

static int count_configs(struct usb_composite_dev *cdev, unsigned type)
{
	struct usb_gadget		*gadget = cdev->gadget;
	struct usb_configuration	*c;
	unsigned			count = 0;
	int				hs = 0;

	if (gadget_is_dualspeed(gadget)) {
		if (gadget->speed == USB_SPEED_HIGH)
			hs = 1;
		if (type == USB_DT_DEVICE_QUALIFIER)
			hs = !hs;
	}
	list_for_each_entry(c, &cdev->configs, list) {
		/* ignore configs that won't work at this speed */
		if (hs) {
			if (!c->highspeed)
				continue;
		} else {
			if (!c->fullspeed)
				continue;
		}
		count++;
	}
	return count;
}

static void device_qual(struct usb_composite_dev *cdev)
{
	struct usb_qualifier_descriptor	*qual = cdev->req->buf;

	qual->bLength = sizeof(*qual);
	qual->bDescriptorType = USB_DT_DEVICE_QUALIFIER;
	/* POLICY: same bcdUSB and device type info at both speeds */
	qual->bcdUSB = cdev->desc.bcdUSB;
	qual->bDeviceClass = cdev->desc.bDeviceClass;
	qual->bDeviceSubClass = cdev->desc.bDeviceSubClass;
	qual->bDeviceProtocol = cdev->desc.bDeviceProtocol;
	/* ASSUME same EP0 fifo size at both speeds */
	qual->bMaxPacketSize0 = cdev->desc.bMaxPacketSize0;
	qual->bNumConfigurations = count_configs(cdev, USB_DT_DEVICE_QUALIFIER);
	qual->bRESERVED = 0;
}

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

static void reset_config(struct usb_composite_dev *cdev)
{
	struct usb_function		*f;

	DBG(cdev, "reset config\n");

	list_for_each_entry(f, &cdev->config->functions, list) {
		if (f->disable)
			f->disable(f);

		bitmap_zero(f->endpoints, 32);
	}
	cdev->config = NULL;
}

static int set_config(struct usb_composite_dev *cdev,
		const struct usb_ctrlrequest *ctrl, unsigned number)
{
	struct usb_gadget	*gadget = cdev->gadget;
	struct usb_configuration *c = NULL;
	int			result = -EINVAL;
	unsigned		power = gadget_is_otg(gadget) ? 8 : 100;
	int			tmp;

	if (cdev->config)
		reset_config(cdev);

	if (number) {
		list_for_each_entry(c, &cdev->configs, list) {
			if (c->bConfigurationValue == number) {
				result = 0;
				break;
			}
		}
		if (result < 0)
			goto done;
	} else
		result = 0;

	INFO(cdev, "%s speed config #%d: %s\n",
		({ char *speed;
		switch (gadget->speed) {
		case USB_SPEED_LOW:	speed = "low"; break;
		case USB_SPEED_FULL:	speed = "full"; break;
		case USB_SPEED_HIGH:	speed = "high"; break;
		default:		speed = "?"; break;
		} ; speed; }), number, c ? c->label : "unconfigured");

	if (!c)
		goto done;

	cdev->config = c;

	/* Initialize all interfaces by setting them to altsetting zero. */
	for (tmp = 0; tmp < MAX_CONFIG_INTERFACES; tmp++) {
		struct usb_function	*f = c->interface[tmp];
		struct usb_descriptor_header **descriptors;

		if (!f)
			break;

		/*
		 * Record which endpoints are used by the function. This is used
		 * to dispatch control requests targeted at that endpoint to the
		 * function's setup callback instead of the current
		 * configuration's setup callback.
		 */
		if (gadget->speed == USB_SPEED_HIGH)
			descriptors = f->hs_descriptors;
		else
			descriptors = f->descriptors;

		for (; *descriptors; ++descriptors) {
			struct usb_endpoint_descriptor *ep;
			int addr;

			if ((*descriptors)->bDescriptorType != USB_DT_ENDPOINT)
				continue;

			ep = (struct usb_endpoint_descriptor *)*descriptors;
			addr = ((ep->bEndpointAddress & 0x80) >> 3)
			     |  (ep->bEndpointAddress & 0x0f);
			set_bit(addr, f->endpoints);
		}

		result = f->set_alt(f, tmp, 0);
		if (result < 0) {
			DBG(cdev, "interface %d (%s/%p) alt 0 --> %d\n",
					tmp, f->name, f, result);

			reset_config(cdev);
			goto done;
		}
	}

	/* when we return, be sure our power usage is valid */
	power = c->bMaxPower ? (2 * c->bMaxPower) : CONFIG_USB_GADGET_VBUS_DRAW;
done:
	usb_gadget_vbus_draw(gadget, power);
	return result;
}

/**
 * usb_add_config() - add a configuration to a device.
 * @cdev: wraps the USB gadget
 * @config: the configuration, with bConfigurationValue assigned
 * @bind: the configuration's bind function
 * Context: single threaded during gadget setup
 *
 * One of the main tasks of a composite @bind() routine is to
 * add each of the configurations it supports, using this routine.
 *
 * This function returns the value of the configuration's @bind(), which
 * is zero for success else a negative errno value.  Binding configurations
 * assigns global resources including string IDs, and per-configuration
 * resources such as interface IDs and endpoints.
 */
int usb_add_config(struct usb_composite_dev *cdev,
		struct usb_configuration *config,
		int (*bind)(struct usb_configuration *))
{
	int				status = -EINVAL;
	struct usb_configuration	*c;

	DBG(cdev, "adding config #%u '%s'/%p\n",
			config->bConfigurationValue,
			config->label, config);

	if (!config->bConfigurationValue || !bind)
		goto done;

	/* Prevent duplicate configuration identifiers */
	list_for_each_entry(c, &cdev->configs, list) {
		if (c->bConfigurationValue == config->bConfigurationValue) {
			status = -EBUSY;
			goto done;
		}
	}

	config->cdev = cdev;
	list_add_tail(&config->list, &cdev->configs);

	INIT_LIST_HEAD(&config->functions);
	config->next_interface_id = 0;

	status = bind(config);
	if (status < 0) {
		list_del(&config->list);
		config->cdev = NULL;
	} else {
		unsigned	i;

		DBG(cdev, "cfg %d/%p speeds:%s%s\n",
			config->bConfigurationValue, config,
			config->highspeed ? " high" : "",
			config->fullspeed
				? (gadget_is_dualspeed(cdev->gadget)
					? " full"
					: " full/low")
				: "");

		for (i = 0; i < MAX_CONFIG_INTERFACES; i++) {
			struct usb_function	*f = config->interface[i];

			if (!f)
				continue;
			DBG(cdev, "  interface %d = %s/%p\n",
				i, f->name, f);
		}
	}

	/* set_alt(), or next bind(), sets up
	 * ep->driver_data as needed.
	 */
	usb_ep_autoconfig_reset(cdev->gadget);

done:
	if (status)
		DBG(cdev, "added config '%s'/%u --> %d\n", config->label,
				config->bConfigurationValue, status);
	return status;
}

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

/* We support strings in multiple languages ... string descriptor zero
 * says which languages are supported.  The typical case will be that
 * only one language (probably English) is used, with I18N handled on
 * the host side.
 */

static void collect_langs(struct usb_gadget_strings **sp, __le16 *buf)
{
	const struct usb_gadget_strings	*s;
	u16				language;
	__le16				*tmp;

	while (*sp) {
		s = *sp;
		language = cpu_to_le16(s->language);
		for (tmp = buf; *tmp && tmp < &buf[126]; tmp++) {
			if (*tmp == language)
				goto repeat;
		}
		*tmp++ = language;
repeat:
		sp++;
	}
}

static int lookup_string(
	struct usb_gadget_strings	**sp,
	void				*buf,
	u16				language,
	int				id
)
{
	struct usb_gadget_strings	*s;
	int				value;

	while (*sp) {
		s = *sp++;
		if (s->language != language)
			continue;
		value = usb_gadget_get_string(s, id, buf);
		if (value > 0)
			return value;
	}
	return -EINVAL;
}

static int get_string(struct usb_composite_dev *cdev,
		void *buf, u16 language, int id)
{
	struct usb_configuration	*c;
	struct usb_function		*f;
	int				len;
	const char			*str;

	/* Yes, not only is USB's I18N support probably more than most
	 * folk will ever care about ... also, it's all supported here.
	 * (Except for UTF8 support for Unicode's "Astral Planes".)
	 */

	/* 0 == report all available language codes */
	if (id == 0) {
		struct usb_string_descriptor	*s = buf;
		struct usb_gadget_strings	**sp;

		memset(s, 0, 256);
		s->bDescriptorType = USB_DT_STRING;

		sp = composite->strings;
		if (sp)
			collect_langs(sp, s->wData);

		list_for_each_entry(c, &cdev->configs, list) {
			sp = c->strings;
			if (sp)
				collect_langs(sp, s->wData);

			list_for_each_entry(f, &c->functions, list) {
				sp = f->strings;
				if (sp)
					collect_langs(sp, s->wData);
			}
		}

		for (len = 0; len <= 126 && s->wData[len]; len++)
			continue;
		if (!len)
			return -EINVAL;

		s->bLength = 2 * (len + 1);
		return s->bLength;
	}

	/* Otherwise, look up and return a specified string.  First
	 * check if the string has not been overridden.
	 */
	if (cdev->manufacturer_override == id)
		str = iManufacturer ?: composite->iManufacturer ?:
			composite_manufacturer;
	else if (cdev->product_override == id)
		str = iProduct ?: composite->iProduct;
	else if (cdev->serial_override == id)
		str = iSerialNumber;
	else
		str = NULL;
	if (str) {
		struct usb_gadget_strings strings = {
			.language = language,
			.strings  = &(struct usb_string) { 0xff, str }
		};
		return usb_gadget_get_string(&strings, 0xff, buf);
	}

	/* String IDs are device-scoped, so we look up each string
	 * table we're told about.  These lookups are infrequent;
	 * simpler-is-better here.
	 */
	if (composite->strings) {
		len = lookup_string(composite->strings, buf, language, id);
		if (len > 0)
			return len;
	}
	list_for_each_entry(c, &cdev->configs, list) {
		if (c->strings) {
			len = lookup_string(c->strings, buf, language, id);
			if (len > 0)
				return len;
		}
		list_for_each_entry(f, &c->functions, list) {
			if (!f->strings)
				continue;
			len = lookup_string(f->strings, buf, language, id);
			if (len > 0)
				return len;
		}
	}
	return -EINVAL;
}

/**
 * usb_string_id() - allocate an unused string ID
 * @cdev: the device whose string descriptor IDs are being allocated
 * Context: single threaded during gadget setup
 *
 * @usb_string_id() is called from bind() callbacks to allocate
 * string IDs.  Drivers for functions, configurations, or gadgets will
 * then store that ID in the appropriate descriptors and string table.
 *
 * All string identifier should be allocated using this,
 * @usb_string_ids_tab() or @usb_string_ids_n() routine, to ensure
 * that for example different functions don't wrongly assign different
 * meanings to the same identifier.
 */
int usb_string_id(struct usb_composite_dev *cdev)
{
	if (cdev->next_string_id < 254) {
		/* string id 0 is reserved by USB spec for list of
		 * supported languages */
		/* 255 reserved as well? -- mina86 */
		cdev->next_string_id++;
		return cdev->next_string_id;
	}
	return -ENODEV;
}

/**
 * usb_string_ids() - allocate unused string IDs in batch
 * @cdev: the device whose string descriptor IDs are being allocated
 * @str: an array of usb_string objects to assign numbers to
 * Context: single threaded during gadget setup
 *
 * @usb_string_ids() is called from bind() callbacks to allocate
 * string IDs.  Drivers for functions, configurations, or gadgets will
 * then copy IDs from the string table to the appropriate descriptors
 * and string table for other languages.
 *
 * All string identifier should be allocated using this,
 * @usb_string_id() or @usb_string_ids_n() routine, to ensure that for
 * example different functions don't wrongly assign different meanings
 * to the same identifier.
 */
int usb_string_ids_tab(struct usb_composite_dev *cdev, struct usb_string *str)
{
	int next = cdev->next_string_id;

	for (; str->s; ++str) {
		if (unlikely(next >= 254))
			return -ENODEV;
		str->id = ++next;
	}

	cdev->next_string_id = next;

	return 0;
}

/**
 * usb_string_ids_n() - allocate unused string IDs in batch
 * @c: the device whose string descriptor IDs are being allocated
 * @n: number of string IDs to allocate
 * Context: single threaded during gadget setup
 *
 * Returns the first requested ID.  This ID and next @n-1 IDs are now
 * valid IDs.  At least provided that @n is non-zero because if it
 * is, returns last requested ID which is now very useful information.
 *
 * @usb_string_ids_n() is called from bind() callbacks to allocate
 * string IDs.  Drivers for functions, configurations, or gadgets will
 * then store that ID in the appropriate descriptors and string table.
 *
 * All string identifier should be allocated using this,
 * @usb_string_id() or @usb_string_ids_n() routine, to ensure that for
 * example different functions don't wrongly assign different meanings
 * to the same identifier.
 */
int usb_string_ids_n(struct usb_composite_dev *c, unsigned n)
{
	unsigned next = c->next_string_id;
	if (unlikely(n > 254 || (unsigned)next + n > 254))
		return -ENODEV;
	c->next_string_id += n;
	return next + 1;
}


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

static void composite_setup_complete(struct usb_ep *ep, struct usb_request *req)
{
	if (req->status || req->actual != req->length)
		DBG((struct usb_composite_dev *) ep->driver_data,
				"setup complete --> %d, %d/%d\n",
				req->status, req->actual, req->length);
}

/*
 * The setup() callback implements all the ep0 functionality that's
 * not handled lower down, in hardware or the hardware driver(like
 * device and endpoint feature flags, and their status).  It's all
 * housekeeping for the gadget function we're implementing.  Most of
 * the work is in config and function specific setup.
 */
static int
composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
{
	struct usb_composite_dev	*cdev = get_gadget_data(gadget);
	struct usb_request		*req = cdev->req;
	int				value = -EOPNOTSUPP;
	u16				w_index = le16_to_cpu(ctrl->wIndex);
	u8				intf = w_index & 0xFF;
	u16				w_value = le16_to_cpu(ctrl->wValue);
	u16				w_length = le16_to_cpu(ctrl->wLength);
	struct usb_function		*f = NULL;
	u8				endp;

	/* partial re-init of the response message; the function or the
	 * gadget might need to intercept e.g. a control-OUT completion
	 * when we delegate to it.
	 */
	req->zero = 0;
	req->complete = composite_setup_complete;
	req->length = USB_BUFSIZ;
	gadget->ep0->driver_data = cdev;

	switch (ctrl->bRequest) {

	/* we handle all standard USB descriptors */
	case USB_REQ_GET_DESCRIPTOR:
		if (ctrl->bRequestType != USB_DIR_IN)
			goto unknown;
		switch (w_value >> 8) {

		case USB_DT_DEVICE:
			cdev->desc.bNumConfigurations =
				count_configs(cdev, USB_DT_DEVICE);
			value = min(w_length, (u16) sizeof cdev->desc);
			memcpy(req->buf, &cdev->desc, value);
			break;
		case USB_DT_DEVICE_QUALIFIER:
			if (!gadget_is_dualspeed(gadget))
				break;
			device_qual(cdev);
			value = min_t(int, w_length,
				sizeof(struct usb_qualifier_descriptor));
			break;
		case USB_DT_OTHER_SPEED_CONFIG:
			if (!gadget_is_dualspeed(gadget))
				break;
			/* FALLTHROUGH */
		case USB_DT_CONFIG:
			value = config_desc(cdev, w_value);
			if (value >= 0)
				value = min(w_length, (u16) value);
			break;
		case USB_DT_STRING:
			value = get_string(cdev, req->buf,
					w_index, w_value & 0xff);
			if (value >= 0)
				value = min(w_length, (u16) value);
			break;
		}
		break;

	/* any number of configs can work */
	case USB_REQ_SET_CONFIGURATION:
		if (ctrl->bRequestType != 0)
			goto unknown;
		if (gadget_is_otg(gadget)) {
			if (gadget->a_hnp_support)
				DBG(cdev, "HNP available\n");
			else if (gadget->a_alt_hnp_support)
				DBG(cdev, "HNP on another port\n");
			else
				VDBG(cdev, "HNP inactive\n");
		}
		spin_lock(&cdev->lock);
		value = set_config(cdev, ctrl, w_value);
		spin_unlock(&cdev->lock);
		break;
	case USB_REQ_GET_CONFIGURATION:
		if (ctrl->bRequestType != USB_DIR_IN)
			goto unknown;
		if (cdev->config)
			*(u8 *)req->buf = cdev->config->bConfigurationValue;
		else
			*(u8 *)req->buf = 0;
		value = min(w_length, (u16) 1);
		break;

	/* function drivers must handle get/set altsetting; if there's
	 * no get() method, we know only altsetting zero works.
	 */
	case USB_REQ_SET_INTERFACE:
		if (ctrl->bRequestType != USB_RECIP_INTERFACE)
			goto unknown;
		if (!cdev->config || w_index >= MAX_CONFIG_INTERFACES)
			break;
		f = cdev->config->interface[intf];
		if (!f)
			break;
		if (w_value && !f->set_alt)
			break;
		value = f->set_alt(f, w_index, w_value);
		break;
	case USB_REQ_GET_INTERFACE:
		if (ctrl->bRequestType != (USB_DIR_IN|USB_RECIP_INTERFACE))
			goto unknown;
		if (!cdev->config || w_index >= MAX_CONFIG_INTERFACES)
			break;
		f = cdev->config->interface[intf];
		if (!f)
			break;
		/* lots of interfaces only need altsetting zero... */
		value = f->get_alt ? f->get_alt(f, w_index) : 0;
		if (value < 0)
			break;
		*((u8 *)req->buf) = value;
		value = min(w_length, (u16) 1);
		break;
	default:
unknown:
		VDBG(cdev,
			"non-core control req%02x.%02x v%04x i%04x l%d\n",
			ctrl->bRequestType, ctrl->bRequest,
			w_value, w_index, w_length);

		/* functions always handle their interfaces and endpoints...
		 * punt other recipients (other, WUSB, ...) to the current
		 * configuration code.
		 *
		 * REVISIT it could make sense to let the composite device
		 * take such requests too, if that's ever needed:  to work
		 * in config 0, etc.
		 */
		switch (ctrl->bRequestType & USB_RECIP_MASK) {
		case USB_RECIP_INTERFACE:
			if (cdev->config)
				f = cdev->config->interface[intf];
			break;

		case USB_RECIP_ENDPOINT:
			endp = ((w_index & 0x80) >> 3) | (w_index & 0x0f);
			list_for_each_entry(f, &cdev->config->functions, list) {
				if (test_bit(endp, f->endpoints))
					break;
			}
			if (&f->list == &cdev->config->functions)
				f = NULL;
			break;
		}

		if (f && f->setup)
			value = f->setup(f, ctrl);
		else {
			struct usb_configuration	*c;

			c = cdev->config;
			if (c && c->setup)
				value = c->setup(c, ctrl);
		}

		goto done;
	}

	/* respond with data transfer before status phase? */
	if (value >= 0) {
		req->length = value;
		req->zero = value < w_length;
		value = usb_ep_queue(gadget->ep0, req, GFP_ATOMIC);
		if (value < 0) {
			DBG(cdev, "ep_queue --> %d\n", value);
			req->status = 0;
			composite_setup_complete(gadget->ep0, req);
		}
	}

done:
	/* device either stalls (value < 0) or reports success */
	return value;
}

static void composite_disconnect(struct usb_gadget *gadget)
{
	struct usb_composite_dev	*cdev = get_gadget_data(gadget);
	unsigned long			flags;

	/* REVISIT:  should we have config and device level
	 * disconnect callbacks?
	 */
	spin_lock_irqsave(&cdev->lock, flags);
	if (cdev->config)
		reset_config(cdev);
	if (composite->disconnect)
		composite->disconnect(cdev);
	spin_unlock_irqrestore(&cdev->lock, flags);
}

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

static ssize_t composite_show_suspended(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	struct usb_gadget *gadget = dev_to_usb_gadget(dev);
	struct usb_composite_dev *cdev = get_gadget_data(gadget);

	return sprintf(buf, "%d\n", cdev->suspended);
}

static DEVICE_ATTR(suspended, 0444, composite_show_suspended, NULL);

static void
composite_unbind(struct usb_gadget *gadget)
{
	struct usb_composite_dev	*cdev = get_gadget_data(gadget);

	/* composite_disconnect() must already have been called
	 * by the underlying peripheral controller driver!
	 * so there's no i/o concurrency that could affect the
	 * state protected by cdev->lock.
	 */
	WARN_ON(cdev->config);

	while (!list_empty(&cdev->configs)) {
		struct usb_configuration	*c;

		c = list_first_entry(&cdev->configs,
				struct usb_configuration, list);
		while (!list_empty(&c->functions)) {
			struct usb_function		*f;

			f = list_first_entry(&c->functions,
					struct usb_function, list);
			list_del(&f->list);
			if (f->unbind) {
				DBG(cdev, "unbind function '%s'/%p\n",
						f->name, f);
				f->unbind(c, f);
				/* may free memory for "f" */
			}
		}
		list_del(&c->list);
		if (c->unbind) {
			DBG(cdev, "unbind config '%s'/%p\n", c->label, c);
			c->unbind(c);
			/* may free memory for "c" */
		}
	}
	if (composite->unbind)
		composite->unbind(cdev);

	if (cdev->req) {
		kfree(cdev->req->buf);
		usb_ep_free_request(gadget->ep0, cdev->req);
	}
	device_remove_file(&gadget->dev, &dev_attr_suspended);
	kfree(cdev);
	set_gadget_data(gadget, NULL);
	composite = NULL;
}

static u8 override_id(struct usb_composite_dev *cdev, u8 *desc)
{
	if (!*desc) {
		int ret = usb_string_id(cdev);
		if (unlikely(ret < 0))
			WARNING(cdev, "failed to override string ID\n");
		else
			*desc = ret;
	}

	return *desc;
}

static int composite_bind(struct usb_gadget *gadget)
{
	struct usb_composite_dev	*cdev;
	int				status = -ENOMEM;

	cdev = kzalloc(sizeof *cdev, GFP_KERNEL);
	if (!cdev)
		return status;

	spin_lock_init(&cdev->lock);
	cdev->gadget = gadget;
	set_gadget_data(gadget, cdev);
	INIT_LIST_HEAD(&cdev->configs);

	/* preallocate control response and buffer */
	cdev->req = usb_ep_alloc_request(gadget->ep0, GFP_KERNEL);
	if (!cdev->req)
		goto fail;
	cdev->req->buf = kmalloc(USB_BUFSIZ, GFP_KERNEL);
	if (!cdev->req->buf)
		goto fail;
	cdev->req->complete = composite_setup_complete;
	gadget->ep0->driver_data = cdev;

	cdev->bufsiz = USB_BUFSIZ;
	cdev->driver = composite;

	/*
	 * As per USB compliance update, a device that is actively drawing
	 * more than 100mA from USB must report itself as bus-powered in
	 * the GetStatus(DEVICE) call.
	 */
	if (CONFIG_USB_GADGET_VBUS_DRAW <= USB_SELF_POWER_VBUS_MAX_DRAW)
		usb_gadget_set_selfpowered(gadget);

	/* interface and string IDs start at zero via kzalloc.
	 * we force endpoints to start unassigned; few controller
	 * drivers will zero ep->driver_data.
	 */
	usb_ep_autoconfig_reset(cdev->gadget);

	/* standardized runtime overrides for device ID data */
	if (idVendor)
		cdev->desc.idVendor = cpu_to_le16(idVendor);
	if (idProduct)
		cdev->desc.idProduct = cpu_to_le16(idProduct);
	if (bcdDevice)
		cdev->desc.bcdDevice = cpu_to_le16(bcdDevice);

	/* composite gadget needs to assign strings for whole device (like
	 * serial number), register function drivers, potentially update
	 * power state and consumption, etc
	 */
	status = composite_gadget_bind(cdev);
	if (status < 0)
		goto fail;

	cdev->desc = *composite->dev;
	cdev->desc.bMaxPacketSize0 = gadget->ep0->maxpacket;

	/* stirng overrides */
	if (iManufacturer || !cdev->desc.iManufacturer) {
		if (!iManufacturer && !composite->iManufacturer &&
		    !*composite_manufacturer)
			snprintf(composite_manufacturer,
				 sizeof composite_manufacturer,
				 "%s %s with %s",
				 init_utsname()->sysname,
				 init_utsname()->release,
				 gadget->name);

		cdev->manufacturer_override =
			override_id(cdev, &cdev->desc.iManufacturer);
	}

	if (iProduct || (!cdev->desc.iProduct && composite->iProduct))
		cdev->product_override =
			override_id(cdev, &cdev->desc.iProduct);

	if (iSerialNumber)
		cdev->serial_override =
			override_id(cdev, &cdev->desc.iSerialNumber);

	/* has userspace failed to provide a serial number? */
	if (composite->needs_serial && !cdev->desc.iSerialNumber)
		WARNING(cdev, "userspace failed to provide iSerialNumber\n");

	/* finish up */
	status = device_create_file(&gadget->dev, &dev_attr_suspended);
	if (status)
		goto fail;

	INFO(cdev, "%s ready\n", composite->name);
	return 0;

fail:
	composite_unbind(gadget);
	return status;
}

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

static void
composite_suspend(struct usb_gadget *gadget)
{
	struct usb_composite_dev	*cdev = get_gadget_data(gadget);
	struct usb_function		*f;

	/* REVISIT:  should we have config level
	 * suspend/resume callbacks?
	 */
	DBG(cdev, "suspend\n");
	if (cdev->config) {
		list_for_each_entry(f, &cdev->config->functions, list) {
			if (f->suspend)
				f->suspend(f);
		}
	}
	if (composite->suspend)
		composite->suspend(cdev);

	cdev->suspended = 1;
}

static void
composite_resume(struct usb_gadget *gadget)
{
	struct usb_composite_dev	*cdev = get_gadget_data(gadget);
	struct usb_function		*f;

	/* REVISIT:  should we have config level
	 * suspend/resume callbacks?
	 */
	DBG(cdev, "resume\n");
	if (composite->resume)
		composite->resume(cdev);
	if (cdev->config) {
		list_for_each_entry(f, &cdev->config->functions, list) {
			if (f->resume)
				f->resume(f);
		}
	}

	cdev->suspended = 0;
}

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

static struct usb_gadget_driver composite_driver = {
	.speed		= USB_SPEED_HIGH,

	.unbind		= composite_unbind,

	.setup		= composite_setup,
	.disconnect	= composite_disconnect,

	.suspend	= composite_suspend,
	.resume		= composite_resume,

	.driver	= {
		.owner		= THIS_MODULE,
	},
};

/**
 * usb_composite_probe() - register a composite driver
 * @driver: the driver to register
 * @bind: the callback used to allocate resources that are shared across the
 *	whole device, such as string IDs, and add its configurations using
 *	@usb_add_config().  This may fail by returning a negative errno
 *	value; it should return zero on successful initialization.
 * Context: single threaded during gadget setup
 *
 * This function is used to register drivers using the composite driver
 * framework.  The return value is zero, or a negative errno value.
 * Those values normally come from the driver's @bind method, which does
 * all the work of setting up the driver to match the hardware.
 *
 * On successful return, the gadget is ready to respond to requests from
 * the host, unless one of its components invokes usb_gadget_disconnect()
 * while it was binding.  That would usually be done in order to wait for
 * some userspace participation.
 */
extern int usb_composite_probe(struct usb_composite_driver *driver,
			       int (*bind)(struct usb_composite_dev *cdev))
{
	if (!driver || !driver->dev || !bind || composite)
		return -EINVAL;

	if (!driver->iProduct)
		driver->iProduct = driver->name;
	if (!driver->name)
		driver->name = "composite";
	composite_driver.function =  (char *) driver->name;
	composite_driver.driver.name = driver->name;
	composite = driver;
	composite_gadget_bind = bind;

	return usb_gadget_probe_driver(&composite_driver, composite_bind);
}

/**
 * usb_composite_unregister() - unregister a composite driver
 * @driver: the driver to unregister
 *
 * This function is used to unregister drivers using the composite
 * driver framework.
 */
void usb_composite_unregister(struct usb_composite_driver *driver)
{
	if (composite != driver)
		return;
	usb_gadget_unregister_driver(&composite_driver);
}