summaryrefslogtreecommitdiffstats
path: root/drivers/usb/gadget/composite.c
blob: a8c18df171c34cbcad3e0af3f807c32d5f9546cd (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
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
/*
 * 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.
 */

/* #define VERBOSE_DEBUG */

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

#include <linux/usb/composite.h>
#include <asm/unaligned.h>

#include "u_os_desc.h"

/**
 * struct usb_os_string - represents OS String to be reported by a gadget
 * @bLength: total length of the entire descritor, always 0x12
 * @bDescriptorType: USB_DT_STRING
 * @qwSignature: the OS String proper
 * @bMS_VendorCode: code used by the host for subsequent requests
 * @bPad: not used, must be zero
 */
struct usb_os_string {
	__u8	bLength;
	__u8	bDescriptorType;
	__u8	qwSignature[OS_STRING_QW_SIGN_LEN];
	__u8	bMS_VendorCode;
	__u8	bPad;
} __packed;

/*
 * 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.
 */

static struct usb_gadget_strings **get_containers_gs(
		struct usb_gadget_string_container *uc)
{
	return (struct usb_gadget_strings **)uc->stash;
}

/**
 * next_ep_desc() - advance to the next EP descriptor
 * @t: currect pointer within descriptor array
 *
 * Return: next EP descriptor or NULL
 *
 * Iterate over @t until either EP descriptor found or
 * NULL (that indicates end of list) encountered
 */
static struct usb_descriptor_header**
next_ep_desc(struct usb_descriptor_header **t)
{
	for (; *t; t++) {
		if ((*t)->bDescriptorType == USB_DT_ENDPOINT)
			return t;
	}
	return NULL;
}

/*
 * for_each_ep_desc()- iterate over endpoint descriptors in the
 *		descriptors list
 * @start:	pointer within descriptor array.
 * @ep_desc:	endpoint descriptor to use as the loop cursor
 */
#define for_each_ep_desc(start, ep_desc) \
	for (ep_desc = next_ep_desc(start); \
	      ep_desc; ep_desc = next_ep_desc(ep_desc+1))

/**
 * config_ep_by_speed() - configures the given endpoint
 * according to gadget speed.
 * @g: pointer to the gadget
 * @f: usb function
 * @_ep: the endpoint to configure
 *
 * Return: error code, 0 on success
 *
 * This function chooses the right descriptors for a given
 * endpoint according to gadget speed and saves it in the
 * endpoint desc field. If the endpoint already has a descriptor
 * assigned to it - overwrites it with currently corresponding
 * descriptor. The endpoint maxpacket field is updated according
 * to the chosen descriptor.
 * Note: the supplied function should hold all the descriptors
 * for supported speeds
 */
int config_ep_by_speed(struct usb_gadget *g,
			struct usb_function *f,
			struct usb_ep *_ep)
{
	struct usb_composite_dev	*cdev = get_gadget_data(g);
	struct usb_endpoint_descriptor *chosen_desc = NULL;
	struct usb_descriptor_header **speed_desc = NULL;

	struct usb_ss_ep_comp_descriptor *comp_desc = NULL;
	int want_comp_desc = 0;

	struct usb_descriptor_header **d_spd; /* cursor for speed desc */

	if (!g || !f || !_ep)
		return -EIO;

	/* select desired speed */
	switch (g->speed) {
	case USB_SPEED_SUPER:
		if (gadget_is_superspeed(g)) {
			speed_desc = f->ss_descriptors;
			want_comp_desc = 1;
			break;
		}
		/* else: Fall trough */
	case USB_SPEED_HIGH:
		if (gadget_is_dualspeed(g)) {
			speed_desc = f->hs_descriptors;
			break;
		}
		/* else: fall through */
	default:
		speed_desc = f->fs_descriptors;
	}
	/* find descriptors */
	for_each_ep_desc(speed_desc, d_spd) {
		chosen_desc = (struct usb_endpoint_descriptor *)*d_spd;
		if (chosen_desc->bEndpointAddress == _ep->address)
			goto ep_found;
	}
	return -EIO;

ep_found:
	/* commit results */
	_ep->maxpacket = usb_endpoint_maxp(chosen_desc);
	_ep->desc = chosen_desc;
	_ep->comp_desc = NULL;
	_ep->maxburst = 0;
	_ep->mult = 0;
	if (!want_comp_desc)
		return 0;

	/*
	 * Companion descriptor should follow EP descriptor
	 * USB 3.0 spec, #9.6.7
	 */
	comp_desc = (struct usb_ss_ep_comp_descriptor *)*(++d_spd);
	if (!comp_desc ||
	    (comp_desc->bDescriptorType != USB_DT_SS_ENDPOINT_COMP))
		return -EIO;
	_ep->comp_desc = comp_desc;
	if (g->speed == USB_SPEED_SUPER) {
		switch (usb_endpoint_type(_ep->desc)) {
		case USB_ENDPOINT_XFER_ISOC:
			/* mult: bits 1:0 of bmAttributes */
			_ep->mult = comp_desc->bmAttributes & 0x3;
		case USB_ENDPOINT_XFER_BULK:
		case USB_ENDPOINT_XFER_INT:
			_ep->maxburst = comp_desc->bMaxBurst + 1;
			break;
		default:
			if (comp_desc->bMaxBurst != 0)
				ERROR(cdev, "ep0 bMaxBurst must be 0\n");
			_ep->maxburst = 1;
			break;
		}
	}
	return 0;
}
EXPORT_SYMBOL_GPL(config_ep_by_speed);

/**
 * 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->fs_descriptors)
		config->fullspeed = true;
	if (!config->highspeed && function->hs_descriptors)
		config->highspeed = true;
	if (!config->superspeed && function->ss_descriptors)
		config->superspeed = true;

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

void usb_remove_function(struct usb_configuration *c, struct usb_function *f)
{
	if (f->disable)
		f->disable(f);

	bitmap_zero(f->endpoints, 32);
	list_del(&f->list);
	if (f->unbind)
		f->unbind(c, f);
}
EXPORT_SYMBOL_GPL(usb_remove_function);

/**
 * 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;
}
EXPORT_SYMBOL_GPL(usb_function_deactivate);

/**
 * 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;
	unsigned long			flags;
	int				status = 0;

	spin_lock_irqsave(&cdev->lock, flags);

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

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

/**
 * 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 targeted 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
 * identifiers 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;
}
EXPORT_SYMBOL_GPL(usb_interface_id);

static u8 encode_bMaxPower(enum usb_device_speed speed,
		struct usb_configuration *c)
{
	unsigned val;

	if (c->MaxPower)
		val = c->MaxPower;
	else
		val = CONFIG_USB_GADGET_VBUS_DRAW;
	if (!val)
		return 0;
	switch (speed) {
	case USB_SPEED_SUPER:
		return DIV_ROUND_UP(val, 8);
	default:
		return DIV_ROUND_UP(val, 2);
	}
}

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;
	struct usb_function		*f;
	int				status;

	len = USB_COMP_EP0_BUFSIZ - USB_DT_CONFIG_SIZE;
	/* 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 = encode_bMaxPower(speed, config);

	/* 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;

		switch (speed) {
		case USB_SPEED_SUPER:
			descriptors = f->ss_descriptors;
			break;
		case USB_SPEED_HIGH:
			descriptors = f->hs_descriptors;
			break;
		default:
			descriptors = f->fs_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;
	struct list_head		*pos;
	u8				type = w_value >> 8;
	enum usb_device_speed		speed = USB_SPEED_UNKNOWN;

	if (gadget->speed == USB_SPEED_SUPER)
		speed = gadget->speed;
	else 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;

	pos = &cdev->configs;
	c = cdev->os_desc_config;
	if (c)
		goto check_config;

	while ((pos = pos->next) !=  &cdev->configs) {
		c = list_entry(pos, typeof(*c), list);

		/* skip OS Descriptors config which is handled separately */
		if (c == cdev->os_desc_config)
			continue;

check_config:
		/* ignore configs that won't work at this speed */
		switch (speed) {
		case USB_SPEED_SUPER:
			if (!c->superspeed)
				continue;
			break;
		case USB_SPEED_HIGH:
			if (!c->highspeed)
				continue;
			break;
		default:
			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;
	int				ss = 0;

	if (gadget_is_dualspeed(gadget)) {
		if (gadget->speed == USB_SPEED_HIGH)
			hs = 1;
		if (gadget->speed == USB_SPEED_SUPER)
			ss = 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 (ss) {
			if (!c->superspeed)
				continue;
		} else if (hs) {
			if (!c->highspeed)
				continue;
		} else {
			if (!c->fullspeed)
				continue;
		}
		count++;
	}
	return count;
}

/**
 * bos_desc() - prepares the BOS descriptor.
 * @cdev: pointer to usb_composite device to generate the bos
 *	descriptor for
 *
 * This function generates the BOS (Binary Device Object)
 * descriptor and its device capabilities descriptors. The BOS
 * descriptor should be supported by a SuperSpeed device.
 */
static int bos_desc(struct usb_composite_dev *cdev)
{
	struct usb_ext_cap_descriptor	*usb_ext;
	struct usb_ss_cap_descriptor	*ss_cap;
	struct usb_dcd_config_params	dcd_config_params;
	struct usb_bos_descriptor	*bos = cdev->req->buf;

	bos->bLength = USB_DT_BOS_SIZE;
	bos->bDescriptorType = USB_DT_BOS;

	bos->wTotalLength = cpu_to_le16(USB_DT_BOS_SIZE);
	bos->bNumDeviceCaps = 0;

	/*
	 * A SuperSpeed device shall include the USB2.0 extension descriptor
	 * and shall support LPM when operating in USB2.0 HS mode.
	 */
	usb_ext = cdev->req->buf + le16_to_cpu(bos->wTotalLength);
	bos->bNumDeviceCaps++;
	le16_add_cpu(&bos->wTotalLength, USB_DT_USB_EXT_CAP_SIZE);
	usb_ext->bLength = USB_DT_USB_EXT_CAP_SIZE;
	usb_ext->bDescriptorType = USB_DT_DEVICE_CAPABILITY;
	usb_ext->bDevCapabilityType = USB_CAP_TYPE_EXT;
	usb_ext->bmAttributes = cpu_to_le32(USB_LPM_SUPPORT);

	/*
	 * The Superspeed USB Capability descriptor shall be implemented by all
	 * SuperSpeed devices.
	 */
	ss_cap = cdev->req->buf + le16_to_cpu(bos->wTotalLength);
	bos->bNumDeviceCaps++;
	le16_add_cpu(&bos->wTotalLength, USB_DT_USB_SS_CAP_SIZE);
	ss_cap->bLength = USB_DT_USB_SS_CAP_SIZE;
	ss_cap->bDescriptorType = USB_DT_DEVICE_CAPABILITY;
	ss_cap->bDevCapabilityType = USB_SS_CAP_TYPE;
	ss_cap->bmAttributes = 0; /* LTM is not supported yet */
	ss_cap->wSpeedSupported = cpu_to_le16(USB_LOW_SPEED_OPERATION |
				USB_FULL_SPEED_OPERATION |
				USB_HIGH_SPEED_OPERATION |
				USB_5GBPS_OPERATION);
	ss_cap->bFunctionalitySupport = USB_LOW_SPEED_OPERATION;

	/* Get Controller configuration */
	if (cdev->gadget->ops->get_config_params)
		cdev->gadget->ops->get_config_params(&dcd_config_params);
	else {
		dcd_config_params.bU1devExitLat = USB_DEFAULT_U1_DEV_EXIT_LAT;
		dcd_config_params.bU2DevExitLat =
			cpu_to_le16(USB_DEFAULT_U2_DEV_EXIT_LAT);
	}
	ss_cap->bU1devExitLat = dcd_config_params.bU1devExitLat;
	ss_cap->bU2DevExitLat = dcd_config_params.bU2DevExitLat;

	return le16_to_cpu(bos->wTotalLength);
}

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->gadget->ep0->maxpacket;
	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;
	cdev->delayed_status = 0;
}

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 (number) {
		list_for_each_entry(c, &cdev->configs, list) {
			if (c->bConfigurationValue == number) {
				/*
				 * We disable the FDs of the previous
				 * configuration only if the new configuration
				 * is a valid one
				 */
				if (cdev->config)
					reset_config(cdev);
				result = 0;
				break;
			}
		}
		if (result < 0)
			goto done;
	} else { /* Zero configuration value - need to reset the config */
		if (cdev->config)
			reset_config(cdev);
		result = 0;
	}

	INFO(cdev, "%s config #%d: %s\n",
	     usb_speed_string(gadget->speed),
	     number, c ? c->label : "unconfigured");

	if (!c)
		goto done;

	usb_gadget_set_state(gadget, USB_STATE_CONFIGURED);
	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.
		 */
		switch (gadget->speed) {
		case USB_SPEED_SUPER:
			descriptors = f->ss_descriptors;
			break;
		case USB_SPEED_HIGH:
			descriptors = f->hs_descriptors;
			break;
		default:
			descriptors = f->fs_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;
		}

		if (result == USB_GADGET_DELAYED_STATUS) {
			DBG(cdev,
			 "%s: interface %d (%s) requested delayed status\n",
					__func__, tmp, f->name);
			cdev->delayed_status++;
			DBG(cdev, "delayed_status count %d\n",
					cdev->delayed_status);
		}
	}

	/* when we return, be sure our power usage is valid */
	power = c->MaxPower ? c->MaxPower : CONFIG_USB_GADGET_VBUS_DRAW;
done:
	usb_gadget_vbus_draw(gadget, power);
	if (result >= 0 && cdev->delayed_status)
		result = USB_GADGET_DELAYED_STATUS;
	return result;
}

int usb_add_config_only(struct usb_composite_dev *cdev,
		struct usb_configuration *config)
{
	struct usb_configuration *c;

	if (!config->bConfigurationValue)
		return -EINVAL;

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

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

	INIT_LIST_HEAD(&config->functions);
	config->next_interface_id = 0;
	memset(config->interface, 0, sizeof(config->interface));

	return 0;
}
EXPORT_SYMBOL_GPL(usb_add_config_only);

/**
 * 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;

	if (!bind)
		goto done;

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

	status = usb_add_config_only(cdev, config);
	if (status)
		goto done;

	status = bind(config);
	if (status < 0) {
		while (!list_empty(&config->functions)) {
			struct usb_function		*f;

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

		DBG(cdev, "cfg %d/%p speeds:%s%s%s\n",
			config->bConfigurationValue, config,
			config->superspeed ? " super" : "",
			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;
}
EXPORT_SYMBOL_GPL(usb_add_config);

static void remove_config(struct usb_composite_dev *cdev,
			      struct usb_configuration *config)
{
	while (!list_empty(&config->functions)) {
		struct usb_function		*f;

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

/**
 * usb_remove_config() - remove a configuration from a device.
 * @cdev: wraps the USB gadget
 * @config: the configuration
 *
 * Drivers must call usb_gadget_disconnect before calling this function
 * to disconnect the device from the host and make sure the host will not
 * try to enumerate the device while we are changing the config list.
 */
void usb_remove_config(struct usb_composite_dev *cdev,
		      struct usb_configuration *config)
{
	unsigned long flags;

	spin_lock_irqsave(&cdev->lock, flags);

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

	spin_unlock_irqrestore(&cdev->lock, flags);

	remove_config(cdev, config);
}

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

/* 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;
	__le16				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_composite_driver	*composite = cdev->driver;
	struct usb_gadget_string_container *uc;
	struct usb_configuration	*c;
	struct usb_function		*f;
	int				len;

	/* 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);
			}
		}
		list_for_each_entry(uc, &cdev->gstrings, list) {
			struct usb_gadget_strings **sp;

			sp = get_containers_gs(uc);
			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;
	}

	if (cdev->use_os_string && language == 0 && id == OS_STRING_IDX) {
		struct usb_os_string *b = buf;
		b->bLength = sizeof(*b);
		b->bDescriptorType = USB_DT_STRING;
		compiletime_assert(
			sizeof(b->qwSignature) == sizeof(cdev->qw_sign),
			"qwSignature size must be equal to qw_sign");
		memcpy(&b->qwSignature, cdev->qw_sign, sizeof(b->qwSignature));
		b->bMS_VendorCode = cdev->b_vendor_code;
		b->bPad = 0;
		return sizeof(*b);
	}

	list_for_each_entry(uc, &cdev->gstrings, list) {
		struct usb_gadget_strings **sp;

		sp = get_containers_gs(uc);
		len = lookup_string(sp, buf, language, id);
		if (len > 0)
			return len;
	}

	/* 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;
}
EXPORT_SYMBOL_GPL(usb_string_id);

/**
 * 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;
}
EXPORT_SYMBOL_GPL(usb_string_ids_tab);

static struct usb_gadget_string_container *copy_gadget_strings(
		struct usb_gadget_strings **sp, unsigned n_gstrings,
		unsigned n_strings)
{
	struct usb_gadget_string_container *uc;
	struct usb_gadget_strings **gs_array;
	struct usb_gadget_strings *gs;
	struct usb_string *s;
	unsigned mem;
	unsigned n_gs;
	unsigned n_s;
	void *stash;

	mem = sizeof(*uc);
	mem += sizeof(void *) * (n_gstrings + 1);
	mem += sizeof(struct usb_gadget_strings) * n_gstrings;
	mem += sizeof(struct usb_string) * (n_strings + 1) * (n_gstrings);
	uc = kmalloc(mem, GFP_KERNEL);
	if (!uc)
		return ERR_PTR(-ENOMEM);
	gs_array = get_containers_gs(uc);
	stash = uc->stash;
	stash += sizeof(void *) * (n_gstrings + 1);
	for (n_gs = 0; n_gs < n_gstrings; n_gs++) {
		struct usb_string *org_s;

		gs_array[n_gs] = stash;
		gs = gs_array[n_gs];
		stash += sizeof(struct usb_gadget_strings);
		gs->language = sp[n_gs]->language;
		gs->strings = stash;
		org_s = sp[n_gs]->strings;

		for (n_s = 0; n_s < n_strings; n_s++) {
			s = stash;
			stash += sizeof(struct usb_string);
			if (org_s->s)
				s->s = org_s->s;
			else
				s->s = "";
			org_s++;
		}
		s = stash;
		s->s = NULL;
		stash += sizeof(struct usb_string);

	}
	gs_array[n_gs] = NULL;
	return uc;
}

/**
 * usb_gstrings_attach() - attach gadget strings to a cdev and assign ids
 * @cdev: the device whose string descriptor IDs are being allocated
 * and attached.
 * @sp: an array of usb_gadget_strings to attach.
 * @n_strings: number of entries in each usb_strings array (sp[]->strings)
 *
 * This function will create a deep copy of usb_gadget_strings and usb_string
 * and attach it to the cdev. The actual string (usb_string.s) will not be
 * copied but only a referenced will be made. The struct usb_gadget_strings
 * array may contain multiple languges and should be NULL terminated.
 * The ->language pointer of each struct usb_gadget_strings has to contain the
 * same amount of entries.
 * For instance: sp[0] is en-US, sp[1] is es-ES. It is expected that the first
 * usb_string entry of es-ES containts the translation of the first usb_string
 * entry of en-US. Therefore both entries become the same id assign.
 */
struct usb_string *usb_gstrings_attach(struct usb_composite_dev *cdev,
		struct usb_gadget_strings **sp, unsigned n_strings)
{
	struct usb_gadget_string_container *uc;
	struct usb_gadget_strings **n_gs;
	unsigned n_gstrings = 0;
	unsigned i;
	int ret;

	for (i = 0; sp[i]; i++)
		n_gstrings++;

	if (!n_gstrings)
		return ERR_PTR(-EINVAL);

	uc = copy_gadget_strings(sp, n_gstrings, n_strings);
	if (IS_ERR(uc))
		return ERR_CAST(uc);

	n_gs = get_containers_gs(uc);
	ret = usb_string_ids_tab(cdev, n_gs[0]->strings);
	if (ret)
		goto err;

	for (i = 1; i < n_gstrings; i++) {
		struct usb_string *m_s;
		struct usb_string *s;
		unsigned n;

		m_s = n_gs[0]->strings;
		s = n_gs[i]->strings;
		for (n = 0; n < n_strings; n++) {
			s->id = m_s->id;
			s++;
			m_s++;
		}
	}
	list_add_tail(&uc->list, &cdev->gstrings);
	return n_gs[0]->strings;
err:
	kfree(uc);
	return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(usb_gstrings_attach);

/**
 * 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;
}
EXPORT_SYMBOL_GPL(usb_string_ids_n);

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

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);
}

static int count_ext_compat(struct usb_configuration *c)
{
	int i, res;

	res = 0;
	for (i = 0; i < c->next_interface_id; ++i) {
		struct usb_function *f;
		int j;

		f = c->interface[i];
		for (j = 0; j < f->os_desc_n; ++j) {
			struct usb_os_desc *d;

			if (i != f->os_desc_table[j].if_id)
				continue;
			d = f->os_desc_table[j].os_desc;
			if (d && d->ext_compat_id)
				++res;
		}
	}
	BUG_ON(res > 255);
	return res;
}

static void fill_ext_compat(struct usb_configuration *c, u8 *buf)
{
	int i, count;

	count = 16;
	for (i = 0; i < c->next_interface_id; ++i) {
		struct usb_function *f;
		int j;

		f = c->interface[i];
		for (j = 0; j < f->os_desc_n; ++j) {
			struct usb_os_desc *d;

			if (i != f->os_desc_table[j].if_id)
				continue;
			d = f->os_desc_table[j].os_desc;
			if (d && d->ext_compat_id) {
				*buf++ = i;
				*buf++ = 0x01;
				memcpy(buf, d->ext_compat_id, 16);
				buf += 22;
			} else {
				++buf;
				*buf = 0x01;
				buf += 23;
			}
			count += 24;
			if (count >= 4096)
				return;
		}
	}
}

static int count_ext_prop(struct usb_configuration *c, int interface)
{
	struct usb_function *f;
	int j;

	f = c->interface[interface];
	for (j = 0; j < f->os_desc_n; ++j) {
		struct usb_os_desc *d;

		if (interface != f->os_desc_table[j].if_id)
			continue;
		d = f->os_desc_table[j].os_desc;
		if (d && d->ext_compat_id)
			return d->ext_prop_count;
	}
	return 0;
}

static int len_ext_prop(struct usb_configuration *c, int interface)
{
	struct usb_function *f;
	struct usb_os_desc *d;
	int j, res;

	res = 10; /* header length */
	f = c->interface[interface];
	for (j = 0; j < f->os_desc_n; ++j) {
		if (interface != f->os_desc_table[j].if_id)
			continue;
		d = f->os_desc_table[j].os_desc;
		if (d)
			return min(res + d->ext_prop_len, 4096);
	}
	return res;
}

static int fill_ext_prop(struct usb_configuration *c, int interface, u8 *buf)
{
	struct usb_function *f;
	struct usb_os_desc *d;
	struct usb_os_desc_ext_prop *ext_prop;
	int j, count, n, ret;
	u8 *start = buf;

	f = c->interface[interface];
	for (j = 0; j < f->os_desc_n; ++j) {
		if (interface != f->os_desc_table[j].if_id)
			continue;
		d = f->os_desc_table[j].os_desc;
		if (d)
			list_for_each_entry(ext_prop, &d->ext_prop, entry) {
				/* 4kB minus header length */
				n = buf - start;
				if (n >= 4086)
					return 0;

				count = ext_prop->data_len +
					ext_prop->name_len + 14;
				if (count > 4086 - n)
					return -EINVAL;
				usb_ext_prop_put_size(buf, count);
				usb_ext_prop_put_type(buf, ext_prop->type);
				ret = usb_ext_prop_put_name(buf, ext_prop->name,
							    ext_prop->name_len);
				if (ret < 0)
					return ret;
				switch (ext_prop->type) {
				case USB_EXT_PROP_UNICODE:
				case USB_EXT_PROP_UNICODE_ENV:
				case USB_EXT_PROP_UNICODE_LINK:
					usb_ext_prop_put_unicode(buf, ret,
							 ext_prop->data,
							 ext_prop->data_len);
					break;
				case USB_EXT_PROP_BINARY:
					usb_ext_prop_put_binary(buf, ret,
							ext_prop->data,
							ext_prop->data_len);
					break;
				case USB_EXT_PROP_LE32:
					/* not implemented */
				case USB_EXT_PROP_BE32:
					/* not implemented */
				default:
					return -EINVAL;
				}
				buf += count;
			}
	}

	return 0;
}

/*
 * 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.
 */
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;
	int				status = 0;
	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 = 0;
	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);
			cdev->desc.bMaxPacketSize0 =
				cdev->gadget->ep0->maxpacket;
			if (gadget_is_superspeed(gadget)) {
				if (gadget->speed >= USB_SPEED_SUPER) {
					cdev->desc.bcdUSB = cpu_to_le16(0x0300);
					cdev->desc.bMaxPacketSize0 = 9;
				} else {
					cdev->desc.bcdUSB = cpu_to_le16(0x0210);
				}
			}

			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) ||
			    gadget->speed >= USB_SPEED_SUPER)
				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) ||
			    gadget->speed >= USB_SPEED_SUPER)
				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;
		case USB_DT_BOS:
			if (gadget_is_superspeed(gadget)) {
				value = bos_desc(cdev);
				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 || intf >= 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);
		if (value == USB_GADGET_DELAYED_STATUS) {
			DBG(cdev,
			 "%s: interface %d (%s) requested delayed status\n",
					__func__, intf, f->name);
			cdev->delayed_status++;
			DBG(cdev, "delayed_status count %d\n",
					cdev->delayed_status);
		}
		break;
	case USB_REQ_GET_INTERFACE:
		if (ctrl->bRequestType != (USB_DIR_IN|USB_RECIP_INTERFACE))
			goto unknown;
		if (!cdev->config || intf >= 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;

	/*
	 * USB 3.0 additions:
	 * Function driver should handle get_status request. If such cb
	 * wasn't supplied we respond with default value = 0
	 * Note: function driver should supply such cb only for the first
	 * interface of the function
	 */
	case USB_REQ_GET_STATUS:
		if (!gadget_is_superspeed(gadget))
			goto unknown;
		if (ctrl->bRequestType != (USB_DIR_IN | USB_RECIP_INTERFACE))
			goto unknown;
		value = 2;	/* This is the length of the get_status reply */
		put_unaligned_le16(0, req->buf);
		if (!cdev->config || intf >= MAX_CONFIG_INTERFACES)
			break;
		f = cdev->config->interface[intf];
		if (!f)
			break;
		status = f->get_status ? f->get_status(f) : 0;
		if (status < 0)
			break;
		put_unaligned_le16(status & 0x0000ffff, req->buf);
		break;
	/*
	 * Function drivers should handle SetFeature/ClearFeature
	 * (FUNCTION_SUSPEND) request. function_suspend cb should be supplied
	 * only for the first interface of the function
	 */
	case USB_REQ_CLEAR_FEATURE:
	case USB_REQ_SET_FEATURE:
		if (!gadget_is_superspeed(gadget))
			goto unknown;
		if (ctrl->bRequestType != (USB_DIR_OUT | USB_RECIP_INTERFACE))
			goto unknown;
		switch (w_value) {
		case USB_INTRF_FUNC_SUSPEND:
			if (!cdev->config || intf >= MAX_CONFIG_INTERFACES)
				break;
			f = cdev->config->interface[intf];
			if (!f)
				break;
			value = 0;
			if (f->func_suspend)
				value = f->func_suspend(f, w_index >> 8);
			if (value < 0) {
				ERROR(cdev,
				      "func_suspend() returned error %d\n",
				      value);
				value = 0;
			}
			break;
		}
		break;
	default:
unknown:
		/*
		 * OS descriptors handling
		 */
		if (cdev->use_os_string && cdev->os_desc_config &&
		    (ctrl->bRequest & USB_TYPE_VENDOR) &&
		    ctrl->bRequest == cdev->b_vendor_code) {
			struct usb_request		*req;
			struct usb_configuration	*os_desc_cfg;
			u8				*buf;
			int				interface;
			int				count = 0;

			req = cdev->os_desc_req;
			req->complete = composite_setup_complete;
			buf = req->buf;
			os_desc_cfg = cdev->os_desc_config;
			memset(buf, 0, w_length);
			buf[5] = 0x01;
			switch (ctrl->bRequestType & USB_RECIP_MASK) {
			case USB_RECIP_DEVICE:
				if (w_index != 0x4 || (w_value >> 8))
					break;
				buf[6] = w_index;
				if (w_length == 0x10) {
					/* Number of ext compat interfaces */
					count = count_ext_compat(os_desc_cfg);
					buf[8] = count;
					count *= 24; /* 24 B/ext compat desc */
					count += 16; /* header */
					put_unaligned_le32(count, buf);
					value = w_length;
				} else {
					/* "extended compatibility ID"s */
					count = count_ext_compat(os_desc_cfg);
					buf[8] = count;
					count *= 24; /* 24 B/ext compat desc */
					count += 16; /* header */
					put_unaligned_le32(count, buf);
					buf += 16;
					fill_ext_compat(os_desc_cfg, buf);
					value = w_length;
				}
				break;
			case USB_RECIP_INTERFACE:
				if (w_index != 0x5 || (w_value >> 8))
					break;
				interface = w_value & 0xFF;
				buf[6] = w_index;
				if (w_length == 0x0A) {
					count = count_ext_prop(os_desc_cfg,
						interface);
					put_unaligned_le16(count, buf + 8);
					count = len_ext_prop(os_desc_cfg,
						interface);
					put_unaligned_le32(count, buf);

					value = w_length;
				} else {
					count = count_ext_prop(os_desc_cfg,
						interface);
					put_unaligned_le16(count, buf + 8);
					count = len_ext_prop(os_desc_cfg,
						interface);
					put_unaligned_le32(count, buf);
					buf += 10;
					value = fill_ext_prop(os_desc_cfg,
							      interface, buf);
					if (value < 0)
						return value;

					value = w_length;
				}
				break;
			}
			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);
			}
			return value;
		}

		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 || intf >= MAX_CONFIG_INTERFACES)
				break;
			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)
				goto done;

			/* try current config's setup */
			if (c->setup) {
				value = c->setup(c, ctrl);
				goto done;
			}

			/* try the only function in the current config */
			if (!list_is_singular(&c->functions))
				goto done;
			f = list_first_entry(&c->functions, struct usb_function,
					     list);
			if (f->setup)
				value = f->setup(f, ctrl);
		}

		goto done;
	}

	/* respond with data transfer before status phase? */
	if (value >= 0 && value != USB_GADGET_DELAYED_STATUS) {
		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);
		}
	} else if (value == USB_GADGET_DELAYED_STATUS && w_length != 0) {
		WARN(cdev,
			"%s: Delayed status not supported for w_length != 0",
			__func__);
	}

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

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 (cdev->driver->disconnect)
		cdev->driver->disconnect(cdev);
	spin_unlock_irqrestore(&cdev->lock, flags);
}

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

static ssize_t suspended_show(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_RO(suspended);

static void __composite_unbind(struct usb_gadget *gadget, bool unbind_driver)
{
	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);
		remove_config(cdev, c);
	}
	if (cdev->driver->unbind && unbind_driver)
		cdev->driver->unbind(cdev);

	composite_dev_cleanup(cdev);

	kfree(cdev->def_manufacturer);
	kfree(cdev);
	set_gadget_data(gadget, NULL);
}

static void composite_unbind(struct usb_gadget *gadget)
{
	__composite_unbind(gadget, true);
}

static void update_unchanged_dev_desc(struct usb_device_descriptor *new,
		const struct usb_device_descriptor *old)
{
	__le16 idVendor;
	__le16 idProduct;
	__le16 bcdDevice;
	u8 iSerialNumber;
	u8 iManufacturer;
	u8 iProduct;

	/*
	 * these variables may have been set in
	 * usb_composite_overwrite_options()
	 */
	idVendor = new->idVendor;
	idProduct = new->idProduct;
	bcdDevice = new->bcdDevice;
	iSerialNumber = new->iSerialNumber;
	iManufacturer = new->iManufacturer;
	iProduct = new->iProduct;

	*new = *old;
	if (idVendor)
		new->idVendor = idVendor;
	if (idProduct)
		new->idProduct = idProduct;
	if (bcdDevice)
		new->bcdDevice = bcdDevice;
	else
		new->bcdDevice = cpu_to_le16(get_default_bcdDevice());
	if (iSerialNumber)
		new->iSerialNumber = iSerialNumber;
	if (iManufacturer)
		new->iManufacturer = iManufacturer;
	if (iProduct)
		new->iProduct = iProduct;
}

int composite_dev_prepare(struct usb_composite_driver *composite,
		struct usb_composite_dev *cdev)
{
	struct usb_gadget *gadget = cdev->gadget;
	int ret = -ENOMEM;

	/* preallocate control response and buffer */
	cdev->req = usb_ep_alloc_request(gadget->ep0, GFP_KERNEL);
	if (!cdev->req)
		return -ENOMEM;

	cdev->req->buf = kmalloc(USB_COMP_EP0_BUFSIZ, GFP_KERNEL);
	if (!cdev->req->buf)
		goto fail;

	ret = device_create_file(&gadget->dev, &dev_attr_suspended);
	if (ret)
		goto fail_dev;

	cdev->req->complete = composite_setup_complete;
	gadget->ep0->driver_data = cdev;

	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(gadget);
	return 0;
fail_dev:
	kfree(cdev->req->buf);
fail:
	usb_ep_free_request(gadget->ep0, cdev->req);
	cdev->req = NULL;
	return ret;
}

int composite_os_desc_req_prepare(struct usb_composite_dev *cdev,
				  struct usb_ep *ep0)
{
	int ret = 0;

	cdev->os_desc_req = usb_ep_alloc_request(ep0, GFP_KERNEL);
	if (!cdev->os_desc_req) {
		ret = PTR_ERR(cdev->os_desc_req);
		goto end;
	}

	/* OS feature descriptor length <= 4kB */
	cdev->os_desc_req->buf = kmalloc(4096, GFP_KERNEL);
	if (!cdev->os_desc_req->buf) {
		ret = PTR_ERR(cdev->os_desc_req->buf);
		kfree(cdev->os_desc_req);
		goto end;
	}
	cdev->os_desc_req->complete = composite_setup_complete;
end:
	return ret;
}

void composite_dev_cleanup(struct usb_composite_dev *cdev)
{
	struct usb_gadget_string_container *uc, *tmp;

	list_for_each_entry_safe(uc, tmp, &cdev->gstrings, list) {
		list_del(&uc->list);
		kfree(uc);
	}
	if (cdev->os_desc_req) {
		kfree(cdev->os_desc_req->buf);
		usb_ep_free_request(cdev->gadget->ep0, cdev->os_desc_req);
	}
	if (cdev->req) {
		kfree(cdev->req->buf);
		usb_ep_free_request(cdev->gadget->ep0, cdev->req);
	}
	cdev->next_string_id = 0;
	device_remove_file(&cdev->gadget->dev, &dev_attr_suspended);
}

static int composite_bind(struct usb_gadget *gadget,
		struct usb_gadget_driver *gdriver)
{
	struct usb_composite_dev	*cdev;
	struct usb_composite_driver	*composite = to_cdriver(gdriver);
	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);
	INIT_LIST_HEAD(&cdev->gstrings);

	status = composite_dev_prepare(composite, cdev);
	if (status)
		goto fail;

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

	if (cdev->use_os_string) {
		status = composite_os_desc_req_prepare(cdev, gadget->ep0);
		if (status)
			goto fail;
	}

	update_unchanged_dev_desc(&cdev->desc, composite->dev);

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

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

fail:
	__composite_unbind(gadget, false);
	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 (cdev->driver->suspend)
		cdev->driver->suspend(cdev);

	cdev->suspended = 1;

	usb_gadget_vbus_draw(gadget, 2);
}

static void
composite_resume(struct usb_gadget *gadget)
{
	struct usb_composite_dev	*cdev = get_gadget_data(gadget);
	struct usb_function		*f;
	u16				maxpower;

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

		maxpower = cdev->config->MaxPower;

		usb_gadget_vbus_draw(gadget, maxpower ?
			maxpower : CONFIG_USB_GADGET_VBUS_DRAW);
	}

	cdev->suspended = 0;
}

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

static const struct usb_gadget_driver composite_driver_template = {
	.bind		= composite_bind,
	.unbind		= composite_unbind,

	.setup		= composite_setup,
	.reset		= composite_disconnect,
	.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
 *
 * 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.
 */
int usb_composite_probe(struct usb_composite_driver *driver)
{
	struct usb_gadget_driver *gadget_driver;

	if (!driver || !driver->dev || !driver->bind)
		return -EINVAL;

	if (!driver->name)
		driver->name = "composite";

	driver->gadget_driver = composite_driver_template;
	gadget_driver = &driver->gadget_driver;

	gadget_driver->function =  (char *) driver->name;
	gadget_driver->driver.name = driver->name;
	gadget_driver->max_speed = driver->max_speed;

	return usb_gadget_probe_driver(gadget_driver);
}
EXPORT_SYMBOL_GPL(usb_composite_probe);

/**
 * 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)
{
	usb_gadget_unregister_driver(&driver->gadget_driver);
}
EXPORT_SYMBOL_GPL(usb_composite_unregister);

/**
 * usb_composite_setup_continue() - Continue with the control transfer
 * @cdev: the composite device who's control transfer was kept waiting
 *
 * This function must be called by the USB function driver to continue
 * with the control transfer's data/status stage in case it had requested to
 * delay the data/status stages. A USB function's setup handler (e.g. set_alt())
 * can request the composite framework to delay the setup request's data/status
 * stages by returning USB_GADGET_DELAYED_STATUS.
 */
void usb_composite_setup_continue(struct usb_composite_dev *cdev)
{
	int			value;
	struct usb_request	*req = cdev->req;
	unsigned long		flags;

	DBG(cdev, "%s\n", __func__);
	spin_lock_irqsave(&cdev->lock, flags);

	if (cdev->delayed_status == 0) {
		WARN(cdev, "%s: Unexpected call\n", __func__);

	} else if (--cdev->delayed_status == 0) {
		DBG(cdev, "%s: Completing delayed status\n", __func__);
		req->length = 0;
		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
		if (value < 0) {
			DBG(cdev, "ep_queue --> %d\n", value);
			req->status = 0;
			composite_setup_complete(cdev->gadget->ep0, req);
		}
	}

	spin_unlock_irqrestore(&cdev->lock, flags);
}
EXPORT_SYMBOL_GPL(usb_composite_setup_continue);

static char *composite_default_mfr(struct usb_gadget *gadget)
{
	char *mfr;
	int len;

	len = snprintf(NULL, 0, "%s %s with %s", init_utsname()->sysname,
			init_utsname()->release, gadget->name);
	len++;
	mfr = kmalloc(len, GFP_KERNEL);
	if (!mfr)
		return NULL;
	snprintf(mfr, len, "%s %s with %s", init_utsname()->sysname,
			init_utsname()->release, gadget->name);
	return mfr;
}

void usb_composite_overwrite_options(struct usb_composite_dev *cdev,
		struct usb_composite_overwrite *covr)
{
	struct usb_device_descriptor	*desc = &cdev->desc;
	struct usb_gadget_strings	*gstr = cdev->driver->strings[0];
	struct usb_string		*dev_str = gstr->strings;

	if (covr->idVendor)
		desc->idVendor = cpu_to_le16(covr->idVendor);

	if (covr->idProduct)
		desc->idProduct = cpu_to_le16(covr->idProduct);

	if (covr->bcdDevice)
		desc->bcdDevice = cpu_to_le16(covr->bcdDevice);

	if (covr->serial_number) {
		desc->iSerialNumber = dev_str[USB_GADGET_SERIAL_IDX].id;
		dev_str[USB_GADGET_SERIAL_IDX].s = covr->serial_number;
	}
	if (covr->manufacturer) {
		desc->iManufacturer = dev_str[USB_GADGET_MANUFACTURER_IDX].id;
		dev_str[USB_GADGET_MANUFACTURER_IDX].s = covr->manufacturer;

	} else if (!strlen(dev_str[USB_GADGET_MANUFACTURER_IDX].s)) {
		desc->iManufacturer = dev_str[USB_GADGET_MANUFACTURER_IDX].id;
		cdev->def_manufacturer = composite_default_mfr(cdev->gadget);
		dev_str[USB_GADGET_MANUFACTURER_IDX].s = cdev->def_manufacturer;
	}

	if (covr->product) {
		desc->iProduct = dev_str[USB_GADGET_PRODUCT_IDX].id;
		dev_str[USB_GADGET_PRODUCT_IDX].s = covr->product;
	}
}
EXPORT_SYMBOL_GPL(usb_composite_overwrite_options);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Brownell");