summaryrefslogtreecommitdiffstats
path: root/drivers/usb/gadget/file_storage.c
blob: 017a196d041fe58d9617aa2c52148c9f3b258e64 (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
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
/*
 * file_storage.c -- File-backed USB Storage Gadget, for USB development
 *
 * Copyright (C) 2003-2007 Alan Stern
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The names of the above-listed copyright holders may not be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * ALTERNATIVELY, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") as published by the Free Software
 * Foundation, either version 2 of that License or (at your option) any
 * later version.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


/*
 * The File-backed Storage Gadget acts as a USB Mass Storage device,
 * appearing to the host as a disk drive.  In addition to providing an
 * example of a genuinely useful gadget driver for a USB device, it also
 * illustrates a technique of double-buffering for increased throughput.
 * Last but not least, it gives an easy way to probe the behavior of the
 * Mass Storage drivers in a USB host.
 *
 * Backing storage is provided by a regular file or a block device, specified
 * by the "file" module parameter.  Access can be limited to read-only by
 * setting the optional "ro" module parameter.  The gadget will indicate that
 * it has removable media if the optional "removable" module parameter is set.
 *
 * The gadget supports the Control-Bulk (CB), Control-Bulk-Interrupt (CBI),
 * and Bulk-Only (also known as Bulk-Bulk-Bulk or BBB) transports, selected
 * by the optional "transport" module parameter.  It also supports the
 * following protocols: RBC (0x01), ATAPI or SFF-8020i (0x02), QIC-157 (0c03),
 * UFI (0x04), SFF-8070i (0x05), and transparent SCSI (0x06), selected by
 * the optional "protocol" module parameter.  In addition, the default
 * Vendor ID, Product ID, and release number can be overridden.
 *
 * There is support for multiple logical units (LUNs), each of which has
 * its own backing file.  The number of LUNs can be set using the optional
 * "luns" module parameter (anywhere from 1 to 8), and the corresponding
 * files are specified using comma-separated lists for "file" and "ro".
 * The default number of LUNs is taken from the number of "file" elements;
 * it is 1 if "file" is not given.  If "removable" is not set then a backing
 * file must be specified for each LUN.  If it is set, then an unspecified
 * or empty backing filename means the LUN's medium is not loaded.
 *
 * Requirements are modest; only a bulk-in and a bulk-out endpoint are
 * needed (an interrupt-out endpoint is also needed for CBI).  The memory
 * requirement amounts to two 16K buffers, size configurable by a parameter.
 * Support is included for both full-speed and high-speed operation.
 *
 * Note that the driver is slightly non-portable in that it assumes a
 * single memory/DMA buffer will be useable for bulk-in, bulk-out, and
 * interrupt-in endpoints.  With most device controllers this isn't an
 * issue, but there may be some with hardware restrictions that prevent
 * a buffer from being used by more than one endpoint.
 *
 * Module options:
 *
 *	file=filename[,filename...]
 *				Required if "removable" is not set, names of
 *					the files or block devices used for
 *					backing storage
 *	ro=b[,b...]		Default false, booleans for read-only access
 *	removable		Default false, boolean for removable media
 *	luns=N			Default N = number of filenames, number of
 *					LUNs to support
 *	stall			Default determined according to the type of
 *					USB device controller (usually true),
 *					boolean to permit the driver to halt
 *					bulk endpoints
 *	transport=XXX		Default BBB, transport name (CB, CBI, or BBB)
 *	protocol=YYY		Default SCSI, protocol name (RBC, 8020 or
 *					ATAPI, QIC, UFI, 8070, or SCSI;
 *					also 1 - 6)
 *	vendor=0xVVVV		Default 0x0525 (NetChip), USB Vendor ID
 *	product=0xPPPP		Default 0xa4a5 (FSG), USB Product ID
 *	release=0xRRRR		Override the USB release number (bcdDevice)
 *	buflen=N		Default N=16384, buffer size used (will be
 *					rounded down to a multiple of
 *					PAGE_CACHE_SIZE)
 *
 * If CONFIG_USB_FILE_STORAGE_TEST is not set, only the "file", "ro",
 * "removable", "luns", and "stall" options are available; default values
 * are used for everything else.
 *
 * The pathnames of the backing files and the ro settings are available in
 * the attribute files "file" and "ro" in the lun<n> subdirectory of the
 * gadget's sysfs directory.  If the "removable" option is set, writing to
 * these files will simulate ejecting/loading the medium (writing an empty
 * line means eject) and adjusting a write-enable tab.  Changes to the ro
 * setting are not allowed when the medium is loaded.
 *
 * This gadget driver is heavily based on "Gadget Zero" by David Brownell.
 * The driver's SCSI command interface was based on the "Information
 * technology - Small Computer System Interface - 2" document from
 * X3T9.2 Project 375D, Revision 10L, 7-SEP-93, available at
 * <http://www.t10.org/ftp/t10/drafts/s2/s2-r10l.pdf>.  The single exception
 * is opcode 0x23 (READ FORMAT CAPACITIES), which was based on the
 * "Universal Serial Bus Mass Storage Class UFI Command Specification"
 * document, Revision 1.0, December 14, 1998, available at
 * <http://www.usb.org/developers/devclass_docs/usbmass-ufi10.pdf>.
 */


/*
 *				Driver Design
 *
 * The FSG driver is fairly straightforward.  There is a main kernel
 * thread that handles most of the work.  Interrupt routines field
 * callbacks from the controller driver: bulk- and interrupt-request
 * completion notifications, endpoint-0 events, and disconnect events.
 * Completion events are passed to the main thread by wakeup calls.  Many
 * ep0 requests are handled at interrupt time, but SetInterface,
 * SetConfiguration, and device reset requests are forwarded to the
 * thread in the form of "exceptions" using SIGUSR1 signals (since they
 * should interrupt any ongoing file I/O operations).
 *
 * The thread's main routine implements the standard command/data/status
 * parts of a SCSI interaction.  It and its subroutines are full of tests
 * for pending signals/exceptions -- all this polling is necessary since
 * the kernel has no setjmp/longjmp equivalents.  (Maybe this is an
 * indication that the driver really wants to be running in userspace.)
 * An important point is that so long as the thread is alive it keeps an
 * open reference to the backing file.  This will prevent unmounting
 * the backing file's underlying filesystem and could cause problems
 * during system shutdown, for example.  To prevent such problems, the
 * thread catches INT, TERM, and KILL signals and converts them into
 * an EXIT exception.
 *
 * In normal operation the main thread is started during the gadget's
 * fsg_bind() callback and stopped during fsg_unbind().  But it can also
 * exit when it receives a signal, and there's no point leaving the
 * gadget running when the thread is dead.  So just before the thread
 * exits, it deregisters the gadget driver.  This makes things a little
 * tricky: The driver is deregistered at two places, and the exiting
 * thread can indirectly call fsg_unbind() which in turn can tell the
 * thread to exit.  The first problem is resolved through the use of the
 * REGISTERED atomic bitflag; the driver will only be deregistered once.
 * The second problem is resolved by having fsg_unbind() check
 * fsg->state; it won't try to stop the thread if the state is already
 * FSG_STATE_TERMINATED.
 *
 * To provide maximum throughput, the driver uses a circular pipeline of
 * buffer heads (struct fsg_buffhd).  In principle the pipeline can be
 * arbitrarily long; in practice the benefits don't justify having more
 * than 2 stages (i.e., double buffering).  But it helps to think of the
 * pipeline as being a long one.  Each buffer head contains a bulk-in and
 * a bulk-out request pointer (since the buffer can be used for both
 * output and input -- directions always are given from the host's
 * point of view) as well as a pointer to the buffer and various state
 * variables.
 *
 * Use of the pipeline follows a simple protocol.  There is a variable
 * (fsg->next_buffhd_to_fill) that points to the next buffer head to use.
 * At any time that buffer head may still be in use from an earlier
 * request, so each buffer head has a state variable indicating whether
 * it is EMPTY, FULL, or BUSY.  Typical use involves waiting for the
 * buffer head to be EMPTY, filling the buffer either by file I/O or by
 * USB I/O (during which the buffer head is BUSY), and marking the buffer
 * head FULL when the I/O is complete.  Then the buffer will be emptied
 * (again possibly by USB I/O, during which it is marked BUSY) and
 * finally marked EMPTY again (possibly by a completion routine).
 *
 * A module parameter tells the driver to avoid stalling the bulk
 * endpoints wherever the transport specification allows.  This is
 * necessary for some UDCs like the SuperH, which cannot reliably clear a
 * halt on a bulk endpoint.  However, under certain circumstances the
 * Bulk-only specification requires a stall.  In such cases the driver
 * will halt the endpoint and set a flag indicating that it should clear
 * the halt in software during the next device reset.  Hopefully this
 * will permit everything to work correctly.  Furthermore, although the
 * specification allows the bulk-out endpoint to halt when the host sends
 * too much data, implementing this would cause an unavoidable race.
 * The driver will always use the "no-stall" approach for OUT transfers.
 *
 * One subtle point concerns sending status-stage responses for ep0
 * requests.  Some of these requests, such as device reset, can involve
 * interrupting an ongoing file I/O operation, which might take an
 * arbitrarily long time.  During that delay the host might give up on
 * the original ep0 request and issue a new one.  When that happens the
 * driver should not notify the host about completion of the original
 * request, as the host will no longer be waiting for it.  So the driver
 * assigns to each ep0 request a unique tag, and it keeps track of the
 * tag value of the request associated with a long-running exception
 * (device-reset, interface-change, or configuration-change).  When the
 * exception handler is finished, the status-stage response is submitted
 * only if the current ep0 request tag is equal to the exception request
 * tag.  Thus only the most recently received ep0 request will get a
 * status-stage response.
 *
 * Warning: This driver source file is too long.  It ought to be split up
 * into a header file plus about 3 separate .c files, to handle the details
 * of the Gadget, USB Mass Storage, and SCSI protocols.
 */


/* #define VERBOSE_DEBUG */
/* #define DUMP_MSGS */


#include <linux/blkdev.h>
#include <linux/completion.h>
#include <linux/dcache.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/fcntl.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/kref.h>
#include <linux/kthread.h>
#include <linux/limits.h>
#include <linux/rwsem.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/freezer.h>
#include <linux/utsname.h>

#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>

#include "gadget_chips.h"


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

#define DRIVER_DESC		"File-backed Storage Gadget"
#define DRIVER_NAME		"g_file_storage"
#define DRIVER_VERSION		"7 August 2007"

static const char longname[] = DRIVER_DESC;
static const char shortname[] = DRIVER_NAME;

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_AUTHOR("Alan Stern");
MODULE_LICENSE("Dual BSD/GPL");

/* Thanks to NetChip Technologies for donating this product ID.
 *
 * DO NOT REUSE THESE IDs with any other driver!!  Ever!!
 * Instead:  allocate your own, using normal USB-IF procedures. */
#define DRIVER_VENDOR_ID	0x0525	// NetChip
#define DRIVER_PRODUCT_ID	0xa4a5	// Linux-USB File-backed Storage Gadget


/*
 * This driver assumes self-powered hardware and has no way for users to
 * trigger remote wakeup.  It uses autoconfiguration to select endpoints
 * and endpoint addresses.
 */


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

#define LDBG(lun,fmt,args...) \
	dev_dbg(&(lun)->dev , fmt , ## args)
#define MDBG(fmt,args...) \
	pr_debug(DRIVER_NAME ": " fmt , ## args)

#ifndef DEBUG
#undef VERBOSE_DEBUG
#undef DUMP_MSGS
#endif /* !DEBUG */

#ifdef VERBOSE_DEBUG
#define VLDBG	LDBG
#else
#define VLDBG(lun,fmt,args...) \
	do { } while (0)
#endif /* VERBOSE_DEBUG */

#define LERROR(lun,fmt,args...) \
	dev_err(&(lun)->dev , fmt , ## args)
#define LWARN(lun,fmt,args...) \
	dev_warn(&(lun)->dev , fmt , ## args)
#define LINFO(lun,fmt,args...) \
	dev_info(&(lun)->dev , fmt , ## args)

#define MINFO(fmt,args...) \
	pr_info(DRIVER_NAME ": " fmt , ## args)

#define DBG(d, fmt, args...) \
	dev_dbg(&(d)->gadget->dev , fmt , ## args)
#define VDBG(d, fmt, args...) \
	dev_vdbg(&(d)->gadget->dev , fmt , ## args)
#define ERROR(d, fmt, args...) \
	dev_err(&(d)->gadget->dev , fmt , ## args)
#define WARN(d, fmt, args...) \
	dev_warn(&(d)->gadget->dev , fmt , ## args)
#define INFO(d, fmt, args...) \
	dev_info(&(d)->gadget->dev , fmt , ## args)


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

/* Encapsulate the module parameter settings */

#define MAX_LUNS	8

static struct {
	char		*file[MAX_LUNS];
	int		ro[MAX_LUNS];
	unsigned int	num_filenames;
	unsigned int	num_ros;
	unsigned int	nluns;

	int		removable;
	int		can_stall;

	char		*transport_parm;
	char		*protocol_parm;
	unsigned short	vendor;
	unsigned short	product;
	unsigned short	release;
	unsigned int	buflen;

	int		transport_type;
	char		*transport_name;
	int		protocol_type;
	char		*protocol_name;

} mod_data = {					// Default values
	.transport_parm		= "BBB",
	.protocol_parm		= "SCSI",
	.removable		= 0,
	.can_stall		= 1,
	.vendor			= DRIVER_VENDOR_ID,
	.product		= DRIVER_PRODUCT_ID,
	.release		= 0xffff,	// Use controller chip type
	.buflen			= 16384,
	};


module_param_array_named(file, mod_data.file, charp, &mod_data.num_filenames,
		S_IRUGO);
MODULE_PARM_DESC(file, "names of backing files or devices");

module_param_array_named(ro, mod_data.ro, bool, &mod_data.num_ros, S_IRUGO);
MODULE_PARM_DESC(ro, "true to force read-only");

module_param_named(luns, mod_data.nluns, uint, S_IRUGO);
MODULE_PARM_DESC(luns, "number of LUNs");

module_param_named(removable, mod_data.removable, bool, S_IRUGO);
MODULE_PARM_DESC(removable, "true to simulate removable media");

module_param_named(stall, mod_data.can_stall, bool, S_IRUGO);
MODULE_PARM_DESC(stall, "false to prevent bulk stalls");


/* In the non-TEST version, only the module parameters listed above
 * are available. */
#ifdef CONFIG_USB_FILE_STORAGE_TEST

module_param_named(transport, mod_data.transport_parm, charp, S_IRUGO);
MODULE_PARM_DESC(transport, "type of transport (BBB, CBI, or CB)");

module_param_named(protocol, mod_data.protocol_parm, charp, S_IRUGO);
MODULE_PARM_DESC(protocol, "type of protocol (RBC, 8020, QIC, UFI, "
		"8070, or SCSI)");

module_param_named(vendor, mod_data.vendor, ushort, S_IRUGO);
MODULE_PARM_DESC(vendor, "USB Vendor ID");

module_param_named(product, mod_data.product, ushort, S_IRUGO);
MODULE_PARM_DESC(product, "USB Product ID");

module_param_named(release, mod_data.release, ushort, S_IRUGO);
MODULE_PARM_DESC(release, "USB release number");

module_param_named(buflen, mod_data.buflen, uint, S_IRUGO);
MODULE_PARM_DESC(buflen, "I/O buffer size");

#endif /* CONFIG_USB_FILE_STORAGE_TEST */


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

/* USB protocol value = the transport method */
#define USB_PR_CBI	0x00		// Control/Bulk/Interrupt
#define USB_PR_CB	0x01		// Control/Bulk w/o interrupt
#define USB_PR_BULK	0x50		// Bulk-only

/* USB subclass value = the protocol encapsulation */
#define USB_SC_RBC	0x01		// Reduced Block Commands (flash)
#define USB_SC_8020	0x02		// SFF-8020i, MMC-2, ATAPI (CD-ROM)
#define USB_SC_QIC	0x03		// QIC-157 (tape)
#define USB_SC_UFI	0x04		// UFI (floppy)
#define USB_SC_8070	0x05		// SFF-8070i (removable)
#define USB_SC_SCSI	0x06		// Transparent SCSI

/* Bulk-only data structures */

/* Command Block Wrapper */
struct bulk_cb_wrap {
	__le32	Signature;		// Contains 'USBC'
	u32	Tag;			// Unique per command id
	__le32	DataTransferLength;	// Size of the data
	u8	Flags;			// Direction in bit 7
	u8	Lun;			// LUN (normally 0)
	u8	Length;			// Of the CDB, <= MAX_COMMAND_SIZE
	u8	CDB[16];		// Command Data Block
};

#define USB_BULK_CB_WRAP_LEN	31
#define USB_BULK_CB_SIG		0x43425355	// Spells out USBC
#define USB_BULK_IN_FLAG	0x80

/* Command Status Wrapper */
struct bulk_cs_wrap {
	__le32	Signature;		// Should = 'USBS'
	u32	Tag;			// Same as original command
	__le32	Residue;		// Amount not transferred
	u8	Status;			// See below
};

#define USB_BULK_CS_WRAP_LEN	13
#define USB_BULK_CS_SIG		0x53425355	// Spells out 'USBS'
#define USB_STATUS_PASS		0
#define USB_STATUS_FAIL		1
#define USB_STATUS_PHASE_ERROR	2

/* Bulk-only class specific requests */
#define USB_BULK_RESET_REQUEST		0xff
#define USB_BULK_GET_MAX_LUN_REQUEST	0xfe


/* CBI Interrupt data structure */
struct interrupt_data {
	u8	bType;
	u8	bValue;
};

#define CBI_INTERRUPT_DATA_LEN		2

/* CBI Accept Device-Specific Command request */
#define USB_CBI_ADSC_REQUEST		0x00


#define MAX_COMMAND_SIZE	16	// Length of a SCSI Command Data Block

/* SCSI commands that we recognize */
#define SC_FORMAT_UNIT			0x04
#define SC_INQUIRY			0x12
#define SC_MODE_SELECT_6		0x15
#define SC_MODE_SELECT_10		0x55
#define SC_MODE_SENSE_6			0x1a
#define SC_MODE_SENSE_10		0x5a
#define SC_PREVENT_ALLOW_MEDIUM_REMOVAL	0x1e
#define SC_READ_6			0x08
#define SC_READ_10			0x28
#define SC_READ_12			0xa8
#define SC_READ_CAPACITY		0x25
#define SC_READ_FORMAT_CAPACITIES	0x23
#define SC_RELEASE			0x17
#define SC_REQUEST_SENSE		0x03
#define SC_RESERVE			0x16
#define SC_SEND_DIAGNOSTIC		0x1d
#define SC_START_STOP_UNIT		0x1b
#define SC_SYNCHRONIZE_CACHE		0x35
#define SC_TEST_UNIT_READY		0x00
#define SC_VERIFY			0x2f
#define SC_WRITE_6			0x0a
#define SC_WRITE_10			0x2a
#define SC_WRITE_12			0xaa

/* SCSI Sense Key/Additional Sense Code/ASC Qualifier values */
#define SS_NO_SENSE				0
#define SS_COMMUNICATION_FAILURE		0x040800
#define SS_INVALID_COMMAND			0x052000
#define SS_INVALID_FIELD_IN_CDB			0x052400
#define SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE	0x052100
#define SS_LOGICAL_UNIT_NOT_SUPPORTED		0x052500
#define SS_MEDIUM_NOT_PRESENT			0x023a00
#define SS_MEDIUM_REMOVAL_PREVENTED		0x055302
#define SS_NOT_READY_TO_READY_TRANSITION	0x062800
#define SS_RESET_OCCURRED			0x062900
#define SS_SAVING_PARAMETERS_NOT_SUPPORTED	0x053900
#define SS_UNRECOVERED_READ_ERROR		0x031100
#define SS_WRITE_ERROR				0x030c02
#define SS_WRITE_PROTECTED			0x072700

#define SK(x)		((u8) ((x) >> 16))	// Sense Key byte, etc.
#define ASC(x)		((u8) ((x) >> 8))
#define ASCQ(x)		((u8) (x))


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

/*
 * These definitions will permit the compiler to avoid generating code for
 * parts of the driver that aren't used in the non-TEST version.  Even gcc
 * can recognize when a test of a constant expression yields a dead code
 * path.
 */

#ifdef CONFIG_USB_FILE_STORAGE_TEST

#define transport_is_bbb()	(mod_data.transport_type == USB_PR_BULK)
#define transport_is_cbi()	(mod_data.transport_type == USB_PR_CBI)
#define protocol_is_scsi()	(mod_data.protocol_type == USB_SC_SCSI)

#else

#define transport_is_bbb()	1
#define transport_is_cbi()	0
#define protocol_is_scsi()	1

#endif /* CONFIG_USB_FILE_STORAGE_TEST */


struct lun {
	struct file	*filp;
	loff_t		file_length;
	loff_t		num_sectors;

	unsigned int	ro : 1;
	unsigned int	prevent_medium_removal : 1;
	unsigned int	registered : 1;
	unsigned int	info_valid : 1;

	u32		sense_data;
	u32		sense_data_info;
	u32		unit_attention_data;

	struct device	dev;
};

#define backing_file_is_open(curlun)	((curlun)->filp != NULL)

static struct lun *dev_to_lun(struct device *dev)
{
	return container_of(dev, struct lun, dev);
}


/* Big enough to hold our biggest descriptor */
#define EP0_BUFSIZE	256
#define DELAYED_STATUS	(EP0_BUFSIZE + 999)	// An impossibly large value

/* Number of buffers we will use.  2 is enough for double-buffering */
#define NUM_BUFFERS	2

enum fsg_buffer_state {
	BUF_STATE_EMPTY = 0,
	BUF_STATE_FULL,
	BUF_STATE_BUSY
};

struct fsg_buffhd {
	void				*buf;
	enum fsg_buffer_state		state;
	struct fsg_buffhd		*next;

	/* The NetChip 2280 is faster, and handles some protocol faults
	 * better, if we don't submit any short bulk-out read requests.
	 * So we will record the intended request length here. */
	unsigned int			bulk_out_intended_length;

	struct usb_request		*inreq;
	int				inreq_busy;
	struct usb_request		*outreq;
	int				outreq_busy;
};

enum fsg_state {
	FSG_STATE_COMMAND_PHASE = -10,		// This one isn't used anywhere
	FSG_STATE_DATA_PHASE,
	FSG_STATE_STATUS_PHASE,

	FSG_STATE_IDLE = 0,
	FSG_STATE_ABORT_BULK_OUT,
	FSG_STATE_RESET,
	FSG_STATE_INTERFACE_CHANGE,
	FSG_STATE_CONFIG_CHANGE,
	FSG_STATE_DISCONNECT,
	FSG_STATE_EXIT,
	FSG_STATE_TERMINATED
};

enum data_direction {
	DATA_DIR_UNKNOWN = 0,
	DATA_DIR_FROM_HOST,
	DATA_DIR_TO_HOST,
	DATA_DIR_NONE
};

struct fsg_dev {
	/* lock protects: state, all the req_busy's, and cbbuf_cmnd */
	spinlock_t		lock;
	struct usb_gadget	*gadget;

	/* filesem protects: backing files in use */
	struct rw_semaphore	filesem;

	/* reference counting: wait until all LUNs are released */
	struct kref		ref;

	struct usb_ep		*ep0;		// Handy copy of gadget->ep0
	struct usb_request	*ep0req;	// For control responses
	unsigned int		ep0_req_tag;
	const char		*ep0req_name;

	struct usb_request	*intreq;	// For interrupt responses
	int			intreq_busy;
	struct fsg_buffhd	*intr_buffhd;

 	unsigned int		bulk_out_maxpacket;
	enum fsg_state		state;		// For exception handling
	unsigned int		exception_req_tag;

	u8			config, new_config;

	unsigned int		running : 1;
	unsigned int		bulk_in_enabled : 1;
	unsigned int		bulk_out_enabled : 1;
	unsigned int		intr_in_enabled : 1;
	unsigned int		phase_error : 1;
	unsigned int		short_packet_received : 1;
	unsigned int		bad_lun_okay : 1;

	unsigned long		atomic_bitflags;
#define REGISTERED		0
#define CLEAR_BULK_HALTS	1
#define SUSPENDED		2

	struct usb_ep		*bulk_in;
	struct usb_ep		*bulk_out;
	struct usb_ep		*intr_in;

	struct fsg_buffhd	*next_buffhd_to_fill;
	struct fsg_buffhd	*next_buffhd_to_drain;
	struct fsg_buffhd	buffhds[NUM_BUFFERS];

	int			thread_wakeup_needed;
	struct completion	thread_notifier;
	struct task_struct	*thread_task;

	int			cmnd_size;
	u8			cmnd[MAX_COMMAND_SIZE];
	enum data_direction	data_dir;
	u32			data_size;
	u32			data_size_from_cmnd;
	u32			tag;
	unsigned int		lun;
	u32			residue;
	u32			usb_amount_left;

	/* The CB protocol offers no way for a host to know when a command
	 * has completed.  As a result the next command may arrive early,
	 * and we will still have to handle it.  For that reason we need
	 * a buffer to store new commands when using CB (or CBI, which
	 * does not oblige a host to wait for command completion either). */
	int			cbbuf_cmnd_size;
	u8			cbbuf_cmnd[MAX_COMMAND_SIZE];

	unsigned int		nluns;
	struct lun		*luns;
	struct lun		*curlun;
};

typedef void (*fsg_routine_t)(struct fsg_dev *);

static int exception_in_progress(struct fsg_dev *fsg)
{
	return (fsg->state > FSG_STATE_IDLE);
}

/* Make bulk-out requests be divisible by the maxpacket size */
static void set_bulk_out_req_length(struct fsg_dev *fsg,
		struct fsg_buffhd *bh, unsigned int length)
{
	unsigned int	rem;

	bh->bulk_out_intended_length = length;
	rem = length % fsg->bulk_out_maxpacket;
	if (rem > 0)
		length += fsg->bulk_out_maxpacket - rem;
	bh->outreq->length = length;
}

static struct fsg_dev			*the_fsg;
static struct usb_gadget_driver		fsg_driver;

static void	close_backing_file(struct lun *curlun);
static void	close_all_backing_files(struct fsg_dev *fsg);


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

#ifdef DUMP_MSGS

static void dump_msg(struct fsg_dev *fsg, const char *label,
		const u8 *buf, unsigned int length)
{
	if (length < 512) {
		DBG(fsg, "%s, length %u:\n", label, length);
		print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET,
				16, 1, buf, length, 0);
	}
}

static void dump_cdb(struct fsg_dev *fsg)
{}

#else

static void dump_msg(struct fsg_dev *fsg, const char *label,
		const u8 *buf, unsigned int length)
{}

#ifdef VERBOSE_DEBUG

static void dump_cdb(struct fsg_dev *fsg)
{
	print_hex_dump(KERN_DEBUG, "SCSI CDB: ", DUMP_PREFIX_NONE,
			16, 1, fsg->cmnd, fsg->cmnd_size, 0);
}

#else

static void dump_cdb(struct fsg_dev *fsg)
{}

#endif /* VERBOSE_DEBUG */
#endif /* DUMP_MSGS */


static int fsg_set_halt(struct fsg_dev *fsg, struct usb_ep *ep)
{
	const char	*name;

	if (ep == fsg->bulk_in)
		name = "bulk-in";
	else if (ep == fsg->bulk_out)
		name = "bulk-out";
	else
		name = ep->name;
	DBG(fsg, "%s set halt\n", name);
	return usb_ep_set_halt(ep);
}


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

/* Routines for unaligned data access */

static u16 get_be16(u8 *buf)
{
	return ((u16) buf[0] << 8) | ((u16) buf[1]);
}

static u32 get_be32(u8 *buf)
{
	return ((u32) buf[0] << 24) | ((u32) buf[1] << 16) |
			((u32) buf[2] << 8) | ((u32) buf[3]);
}

static void put_be16(u8 *buf, u16 val)
{
	buf[0] = val >> 8;
	buf[1] = val;
}

static void put_be32(u8 *buf, u32 val)
{
	buf[0] = val >> 24;
	buf[1] = val >> 16;
	buf[2] = val >> 8;
	buf[3] = val & 0xff;
}


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

/*
 * DESCRIPTORS ... most are static, but strings and (full) configuration
 * descriptors are built on demand.  Also the (static) config and interface
 * descriptors are adjusted during fsg_bind().
 */
#define STRING_MANUFACTURER	1
#define STRING_PRODUCT		2
#define STRING_SERIAL		3
#define STRING_CONFIG		4
#define STRING_INTERFACE	5

/* There is only one configuration. */
#define	CONFIG_VALUE		1

static struct usb_device_descriptor
device_desc = {
	.bLength =		sizeof device_desc,
	.bDescriptorType =	USB_DT_DEVICE,

	.bcdUSB =		__constant_cpu_to_le16(0x0200),
	.bDeviceClass =		USB_CLASS_PER_INTERFACE,

	/* The next three values can be overridden by module parameters */
	.idVendor =		__constant_cpu_to_le16(DRIVER_VENDOR_ID),
	.idProduct =		__constant_cpu_to_le16(DRIVER_PRODUCT_ID),
	.bcdDevice =		__constant_cpu_to_le16(0xffff),

	.iManufacturer =	STRING_MANUFACTURER,
	.iProduct =		STRING_PRODUCT,
	.iSerialNumber =	STRING_SERIAL,
	.bNumConfigurations =	1,
};

static struct usb_config_descriptor
config_desc = {
	.bLength =		sizeof config_desc,
	.bDescriptorType =	USB_DT_CONFIG,

	/* wTotalLength computed by usb_gadget_config_buf() */
	.bNumInterfaces =	1,
	.bConfigurationValue =	CONFIG_VALUE,
	.iConfiguration =	STRING_CONFIG,
	.bmAttributes =		USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
	.bMaxPower =		1,	// self-powered
};

static struct usb_otg_descriptor
otg_desc = {
	.bLength =		sizeof(otg_desc),
	.bDescriptorType =	USB_DT_OTG,

	.bmAttributes =		USB_OTG_SRP,
};

/* There is only one interface. */

static struct usb_interface_descriptor
intf_desc = {
	.bLength =		sizeof intf_desc,
	.bDescriptorType =	USB_DT_INTERFACE,

	.bNumEndpoints =	2,		// Adjusted during fsg_bind()
	.bInterfaceClass =	USB_CLASS_MASS_STORAGE,
	.bInterfaceSubClass =	USB_SC_SCSI,	// Adjusted during fsg_bind()
	.bInterfaceProtocol =	USB_PR_BULK,	// Adjusted during fsg_bind()
	.iInterface =		STRING_INTERFACE,
};

/* Three full-speed endpoint descriptors: bulk-in, bulk-out,
 * and interrupt-in. */

static struct usb_endpoint_descriptor
fs_bulk_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_IN,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	/* wMaxPacketSize set by autoconfiguration */
};

static struct usb_endpoint_descriptor
fs_bulk_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_OUT,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	/* wMaxPacketSize set by autoconfiguration */
};

static struct usb_endpoint_descriptor
fs_intr_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_IN,
	.bmAttributes =		USB_ENDPOINT_XFER_INT,
	.wMaxPacketSize =	__constant_cpu_to_le16(2),
	.bInterval =		32,	// frames -> 32 ms
};

static const struct usb_descriptor_header *fs_function[] = {
	(struct usb_descriptor_header *) &otg_desc,
	(struct usb_descriptor_header *) &intf_desc,
	(struct usb_descriptor_header *) &fs_bulk_in_desc,
	(struct usb_descriptor_header *) &fs_bulk_out_desc,
	(struct usb_descriptor_header *) &fs_intr_in_desc,
	NULL,
};
#define FS_FUNCTION_PRE_EP_ENTRIES	2


/*
 * USB 2.0 devices need to expose both high speed and full speed
 * descriptors, unless they only run at full speed.
 *
 * That means alternate endpoint descriptors (bigger packets)
 * and a "device qualifier" ... plus more construction options
 * for the config descriptor.
 */
static struct usb_qualifier_descriptor
dev_qualifier = {
	.bLength =		sizeof dev_qualifier,
	.bDescriptorType =	USB_DT_DEVICE_QUALIFIER,

	.bcdUSB =		__constant_cpu_to_le16(0x0200),
	.bDeviceClass =		USB_CLASS_PER_INTERFACE,

	.bNumConfigurations =	1,
};

static struct usb_endpoint_descriptor
hs_bulk_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	/* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	__constant_cpu_to_le16(512),
};

static struct usb_endpoint_descriptor
hs_bulk_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	/* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	__constant_cpu_to_le16(512),
	.bInterval =		1,	// NAK every 1 uframe
};

static struct usb_endpoint_descriptor
hs_intr_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	/* bEndpointAddress copied from fs_intr_in_desc during fsg_bind() */
	.bmAttributes =		USB_ENDPOINT_XFER_INT,
	.wMaxPacketSize =	__constant_cpu_to_le16(2),
	.bInterval =		9,	// 2**(9-1) = 256 uframes -> 32 ms
};

static const struct usb_descriptor_header *hs_function[] = {
	(struct usb_descriptor_header *) &otg_desc,
	(struct usb_descriptor_header *) &intf_desc,
	(struct usb_descriptor_header *) &hs_bulk_in_desc,
	(struct usb_descriptor_header *) &hs_bulk_out_desc,
	(struct usb_descriptor_header *) &hs_intr_in_desc,
	NULL,
};
#define HS_FUNCTION_PRE_EP_ENTRIES	2

/* Maxpacket and other transfer characteristics vary by speed. */
static struct usb_endpoint_descriptor *
ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *fs,
		struct usb_endpoint_descriptor *hs)
{
	if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
		return hs;
	return fs;
}


/* The CBI specification limits the serial string to 12 uppercase hexadecimal
 * characters. */
static char				manufacturer[64];
static char				serial[13];

/* Static strings, in UTF-8 (for simplicity we use only ASCII characters) */
static struct usb_string		strings[] = {
	{STRING_MANUFACTURER,	manufacturer},
	{STRING_PRODUCT,	longname},
	{STRING_SERIAL,		serial},
	{STRING_CONFIG,		"Self-powered"},
	{STRING_INTERFACE,	"Mass Storage"},
	{}
};

static struct usb_gadget_strings	stringtab = {
	.language	= 0x0409,		// en-us
	.strings	= strings,
};


/*
 * Config descriptors must agree with the code that sets configurations
 * and with code managing interfaces and their altsettings.  They must
 * also handle different speeds and other-speed requests.
 */
static int populate_config_buf(struct usb_gadget *gadget,
		u8 *buf, u8 type, unsigned index)
{
	enum usb_device_speed			speed = gadget->speed;
	int					len;
	const struct usb_descriptor_header	**function;

	if (index > 0)
		return -EINVAL;

	if (gadget_is_dualspeed(gadget) && type == USB_DT_OTHER_SPEED_CONFIG)
		speed = (USB_SPEED_FULL + USB_SPEED_HIGH) - speed;
	if (gadget_is_dualspeed(gadget) && speed == USB_SPEED_HIGH)
		function = hs_function;
	else
		function = fs_function;

	/* for now, don't advertise srp-only devices */
	if (!gadget_is_otg(gadget))
		function++;

	len = usb_gadget_config_buf(&config_desc, buf, EP0_BUFSIZE, function);
	((struct usb_config_descriptor *) buf)->bDescriptorType = type;
	return len;
}


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

/* These routines may be called in process context or in_irq */

/* Caller must hold fsg->lock */
static void wakeup_thread(struct fsg_dev *fsg)
{
	/* Tell the main thread that something has happened */
	fsg->thread_wakeup_needed = 1;
	if (fsg->thread_task)
		wake_up_process(fsg->thread_task);
}


static void raise_exception(struct fsg_dev *fsg, enum fsg_state new_state)
{
	unsigned long		flags;

	/* Do nothing if a higher-priority exception is already in progress.
	 * If a lower-or-equal priority exception is in progress, preempt it
	 * and notify the main thread by sending it a signal. */
	spin_lock_irqsave(&fsg->lock, flags);
	if (fsg->state <= new_state) {
		fsg->exception_req_tag = fsg->ep0_req_tag;
		fsg->state = new_state;
		if (fsg->thread_task)
			send_sig_info(SIGUSR1, SEND_SIG_FORCED,
					fsg->thread_task);
	}
	spin_unlock_irqrestore(&fsg->lock, flags);
}


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

/* The disconnect callback and ep0 routines.  These always run in_irq,
 * except that ep0_queue() is called in the main thread to acknowledge
 * completion of various requests: set config, set interface, and
 * Bulk-only device reset. */

static void fsg_disconnect(struct usb_gadget *gadget)
{
	struct fsg_dev		*fsg = get_gadget_data(gadget);

	DBG(fsg, "disconnect or port reset\n");
	raise_exception(fsg, FSG_STATE_DISCONNECT);
}


static int ep0_queue(struct fsg_dev *fsg)
{
	int	rc;

	rc = usb_ep_queue(fsg->ep0, fsg->ep0req, GFP_ATOMIC);
	if (rc != 0 && rc != -ESHUTDOWN) {

		/* We can't do much more than wait for a reset */
		WARN(fsg, "error in submission: %s --> %d\n",
				fsg->ep0->name, rc);
	}
	return rc;
}

static void ep0_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct fsg_dev		*fsg = ep->driver_data;

	if (req->actual > 0)
		dump_msg(fsg, fsg->ep0req_name, req->buf, req->actual);
	if (req->status || req->actual != req->length)
		DBG(fsg, "%s --> %d, %u/%u\n", __FUNCTION__,
				req->status, req->actual, req->length);
	if (req->status == -ECONNRESET)		// Request was cancelled
		usb_ep_fifo_flush(ep);

	if (req->status == 0 && req->context)
		((fsg_routine_t) (req->context))(fsg);
}


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

/* Bulk and interrupt endpoint completion handlers.
 * These always run in_irq. */

static void bulk_in_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct fsg_dev		*fsg = ep->driver_data;
	struct fsg_buffhd	*bh = req->context;

	if (req->status || req->actual != req->length)
		DBG(fsg, "%s --> %d, %u/%u\n", __FUNCTION__,
				req->status, req->actual, req->length);
	if (req->status == -ECONNRESET)		// Request was cancelled
		usb_ep_fifo_flush(ep);

	/* Hold the lock while we update the request and buffer states */
	smp_wmb();
	spin_lock(&fsg->lock);
	bh->inreq_busy = 0;
	bh->state = BUF_STATE_EMPTY;
	wakeup_thread(fsg);
	spin_unlock(&fsg->lock);
}

static void bulk_out_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct fsg_dev		*fsg = ep->driver_data;
	struct fsg_buffhd	*bh = req->context;

	dump_msg(fsg, "bulk-out", req->buf, req->actual);
	if (req->status || req->actual != bh->bulk_out_intended_length)
		DBG(fsg, "%s --> %d, %u/%u\n", __FUNCTION__,
				req->status, req->actual,
				bh->bulk_out_intended_length);
	if (req->status == -ECONNRESET)		// Request was cancelled
		usb_ep_fifo_flush(ep);

	/* Hold the lock while we update the request and buffer states */
	smp_wmb();
	spin_lock(&fsg->lock);
	bh->outreq_busy = 0;
	bh->state = BUF_STATE_FULL;
	wakeup_thread(fsg);
	spin_unlock(&fsg->lock);
}


#ifdef CONFIG_USB_FILE_STORAGE_TEST
static void intr_in_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct fsg_dev		*fsg = ep->driver_data;
	struct fsg_buffhd	*bh = req->context;

	if (req->status || req->actual != req->length)
		DBG(fsg, "%s --> %d, %u/%u\n", __FUNCTION__,
				req->status, req->actual, req->length);
	if (req->status == -ECONNRESET)		// Request was cancelled
		usb_ep_fifo_flush(ep);

	/* Hold the lock while we update the request and buffer states */
	smp_wmb();
	spin_lock(&fsg->lock);
	fsg->intreq_busy = 0;
	bh->state = BUF_STATE_EMPTY;
	wakeup_thread(fsg);
	spin_unlock(&fsg->lock);
}

#else
static void intr_in_complete(struct usb_ep *ep, struct usb_request *req)
{}
#endif /* CONFIG_USB_FILE_STORAGE_TEST */


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

/* Ep0 class-specific handlers.  These always run in_irq. */

#ifdef CONFIG_USB_FILE_STORAGE_TEST
static void received_cbi_adsc(struct fsg_dev *fsg, struct fsg_buffhd *bh)
{
	struct usb_request	*req = fsg->ep0req;
	static u8		cbi_reset_cmnd[6] = {
			SC_SEND_DIAGNOSTIC, 4, 0xff, 0xff, 0xff, 0xff};

	/* Error in command transfer? */
	if (req->status || req->length != req->actual ||
			req->actual < 6 || req->actual > MAX_COMMAND_SIZE) {

		/* Not all controllers allow a protocol stall after
		 * receiving control-out data, but we'll try anyway. */
		fsg_set_halt(fsg, fsg->ep0);
		return;			// Wait for reset
	}

	/* Is it the special reset command? */
	if (req->actual >= sizeof cbi_reset_cmnd &&
			memcmp(req->buf, cbi_reset_cmnd,
				sizeof cbi_reset_cmnd) == 0) {

		/* Raise an exception to stop the current operation
		 * and reinitialize our state. */
		DBG(fsg, "cbi reset request\n");
		raise_exception(fsg, FSG_STATE_RESET);
		return;
	}

	VDBG(fsg, "CB[I] accept device-specific command\n");
	spin_lock(&fsg->lock);

	/* Save the command for later */
	if (fsg->cbbuf_cmnd_size)
		WARN(fsg, "CB[I] overwriting previous command\n");
	fsg->cbbuf_cmnd_size = req->actual;
	memcpy(fsg->cbbuf_cmnd, req->buf, fsg->cbbuf_cmnd_size);

	wakeup_thread(fsg);
	spin_unlock(&fsg->lock);
}

#else
static void received_cbi_adsc(struct fsg_dev *fsg, struct fsg_buffhd *bh)
{}
#endif /* CONFIG_USB_FILE_STORAGE_TEST */


static int class_setup_req(struct fsg_dev *fsg,
		const struct usb_ctrlrequest *ctrl)
{
	struct usb_request	*req = fsg->ep0req;
	int			value = -EOPNOTSUPP;
	u16			w_index = le16_to_cpu(ctrl->wIndex);
	u16                     w_value = le16_to_cpu(ctrl->wValue);
	u16			w_length = le16_to_cpu(ctrl->wLength);

	if (!fsg->config)
		return value;

	/* Handle Bulk-only class-specific requests */
	if (transport_is_bbb()) {
		switch (ctrl->bRequest) {

		case USB_BULK_RESET_REQUEST:
			if (ctrl->bRequestType != (USB_DIR_OUT |
					USB_TYPE_CLASS | USB_RECIP_INTERFACE))
				break;
			if (w_index != 0 || w_value != 0) {
				value = -EDOM;
				break;
			}

			/* Raise an exception to stop the current operation
			 * and reinitialize our state. */
			DBG(fsg, "bulk reset request\n");
			raise_exception(fsg, FSG_STATE_RESET);
			value = DELAYED_STATUS;
			break;

		case USB_BULK_GET_MAX_LUN_REQUEST:
			if (ctrl->bRequestType != (USB_DIR_IN |
					USB_TYPE_CLASS | USB_RECIP_INTERFACE))
				break;
			if (w_index != 0 || w_value != 0) {
				value = -EDOM;
				break;
			}
			VDBG(fsg, "get max LUN\n");
			*(u8 *) req->buf = fsg->nluns - 1;
			value = 1;
			break;
		}
	}

	/* Handle CBI class-specific requests */
	else {
		switch (ctrl->bRequest) {

		case USB_CBI_ADSC_REQUEST:
			if (ctrl->bRequestType != (USB_DIR_OUT |
					USB_TYPE_CLASS | USB_RECIP_INTERFACE))
				break;
			if (w_index != 0 || w_value != 0) {
				value = -EDOM;
				break;
			}
			if (w_length > MAX_COMMAND_SIZE) {
				value = -EOVERFLOW;
				break;
			}
			value = w_length;
			fsg->ep0req->context = received_cbi_adsc;
			break;
		}
	}

	if (value == -EOPNOTSUPP)
		VDBG(fsg,
			"unknown class-specific control req "
			"%02x.%02x v%04x i%04x l%u\n",
			ctrl->bRequestType, ctrl->bRequest,
			le16_to_cpu(ctrl->wValue), w_index, w_length);
	return value;
}


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

/* Ep0 standard request handlers.  These always run in_irq. */

static int standard_setup_req(struct fsg_dev *fsg,
		const struct usb_ctrlrequest *ctrl)
{
	struct usb_request	*req = fsg->ep0req;
	int			value = -EOPNOTSUPP;
	u16			w_index = le16_to_cpu(ctrl->wIndex);
	u16			w_value = le16_to_cpu(ctrl->wValue);

	/* Usually this just stores reply data in the pre-allocated ep0 buffer,
	 * but config change events will also reconfigure hardware. */
	switch (ctrl->bRequest) {

	case USB_REQ_GET_DESCRIPTOR:
		if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_STANDARD |
				USB_RECIP_DEVICE))
			break;
		switch (w_value >> 8) {

		case USB_DT_DEVICE:
			VDBG(fsg, "get device descriptor\n");
			value = sizeof device_desc;
			memcpy(req->buf, &device_desc, value);
			break;
		case USB_DT_DEVICE_QUALIFIER:
			VDBG(fsg, "get device qualifier\n");
			if (!gadget_is_dualspeed(fsg->gadget))
				break;
			value = sizeof dev_qualifier;
			memcpy(req->buf, &dev_qualifier, value);
			break;

		case USB_DT_OTHER_SPEED_CONFIG:
			VDBG(fsg, "get other-speed config descriptor\n");
			if (!gadget_is_dualspeed(fsg->gadget))
				break;
			goto get_config;
		case USB_DT_CONFIG:
			VDBG(fsg, "get configuration descriptor\n");
get_config:
			value = populate_config_buf(fsg->gadget,
					req->buf,
					w_value >> 8,
					w_value & 0xff);
			break;

		case USB_DT_STRING:
			VDBG(fsg, "get string descriptor\n");

			/* wIndex == language code */
			value = usb_gadget_get_string(&stringtab,
					w_value & 0xff, req->buf);
			break;
		}
		break;

	/* One config, two speeds */
	case USB_REQ_SET_CONFIGURATION:
		if (ctrl->bRequestType != (USB_DIR_OUT | USB_TYPE_STANDARD |
				USB_RECIP_DEVICE))
			break;
		VDBG(fsg, "set configuration\n");
		if (w_value == CONFIG_VALUE || w_value == 0) {
			fsg->new_config = w_value;

			/* Raise an exception to wipe out previous transaction
			 * state (queued bufs, etc) and set the new config. */
			raise_exception(fsg, FSG_STATE_CONFIG_CHANGE);
			value = DELAYED_STATUS;
		}
		break;
	case USB_REQ_GET_CONFIGURATION:
		if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_STANDARD |
				USB_RECIP_DEVICE))
			break;
		VDBG(fsg, "get configuration\n");
		*(u8 *) req->buf = fsg->config;
		value = 1;
		break;

	case USB_REQ_SET_INTERFACE:
		if (ctrl->bRequestType != (USB_DIR_OUT| USB_TYPE_STANDARD |
				USB_RECIP_INTERFACE))
			break;
		if (fsg->config && w_index == 0) {

			/* Raise an exception to wipe out previous transaction
			 * state (queued bufs, etc) and install the new
			 * interface altsetting. */
			raise_exception(fsg, FSG_STATE_INTERFACE_CHANGE);
			value = DELAYED_STATUS;
		}
		break;
	case USB_REQ_GET_INTERFACE:
		if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_STANDARD |
				USB_RECIP_INTERFACE))
			break;
		if (!fsg->config)
			break;
		if (w_index != 0) {
			value = -EDOM;
			break;
		}
		VDBG(fsg, "get interface\n");
		*(u8 *) req->buf = 0;
		value = 1;
		break;

	default:
		VDBG(fsg,
			"unknown control req %02x.%02x v%04x i%04x l%u\n",
			ctrl->bRequestType, ctrl->bRequest,
			w_value, w_index, le16_to_cpu(ctrl->wLength));
	}

	return value;
}


static int fsg_setup(struct usb_gadget *gadget,
		const struct usb_ctrlrequest *ctrl)
{
	struct fsg_dev		*fsg = get_gadget_data(gadget);
	int			rc;
	int			w_length = le16_to_cpu(ctrl->wLength);

	++fsg->ep0_req_tag;		// Record arrival of a new request
	fsg->ep0req->context = NULL;
	fsg->ep0req->length = 0;
	dump_msg(fsg, "ep0-setup", (u8 *) ctrl, sizeof(*ctrl));

	if ((ctrl->bRequestType & USB_TYPE_MASK) == USB_TYPE_CLASS)
		rc = class_setup_req(fsg, ctrl);
	else
		rc = standard_setup_req(fsg, ctrl);

	/* Respond with data/status or defer until later? */
	if (rc >= 0 && rc != DELAYED_STATUS) {
		rc = min(rc, w_length);
		fsg->ep0req->length = rc;
		fsg->ep0req->zero = rc < w_length;
		fsg->ep0req_name = (ctrl->bRequestType & USB_DIR_IN ?
				"ep0-in" : "ep0-out");
		rc = ep0_queue(fsg);
	}

	/* Device either stalls (rc < 0) or reports success */
	return rc;
}


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

/* All the following routines run in process context */


/* Use this for bulk or interrupt transfers, not ep0 */
static void start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
		struct usb_request *req, int *pbusy,
		enum fsg_buffer_state *state)
{
	int	rc;

	if (ep == fsg->bulk_in)
		dump_msg(fsg, "bulk-in", req->buf, req->length);
	else if (ep == fsg->intr_in)
		dump_msg(fsg, "intr-in", req->buf, req->length);

	spin_lock_irq(&fsg->lock);
	*pbusy = 1;
	*state = BUF_STATE_BUSY;
	spin_unlock_irq(&fsg->lock);
	rc = usb_ep_queue(ep, req, GFP_KERNEL);
	if (rc != 0) {
		*pbusy = 0;
		*state = BUF_STATE_EMPTY;

		/* We can't do much more than wait for a reset */

		/* Note: currently the net2280 driver fails zero-length
		 * submissions if DMA is enabled. */
		if (rc != -ESHUTDOWN && !(rc == -EOPNOTSUPP &&
						req->length == 0))
			WARN(fsg, "error in submission: %s --> %d\n",
					ep->name, rc);
	}
}


static int sleep_thread(struct fsg_dev *fsg)
{
	int	rc = 0;

	/* Wait until a signal arrives or we are woken up */
	for (;;) {
		try_to_freeze();
		set_current_state(TASK_INTERRUPTIBLE);
		if (signal_pending(current)) {
			rc = -EINTR;
			break;
		}
		if (fsg->thread_wakeup_needed)
			break;
		schedule();
	}
	__set_current_state(TASK_RUNNING);
	fsg->thread_wakeup_needed = 0;
	return rc;
}


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

static int do_read(struct fsg_dev *fsg)
{
	struct lun		*curlun = fsg->curlun;
	u32			lba;
	struct fsg_buffhd	*bh;
	int			rc;
	u32			amount_left;
	loff_t			file_offset, file_offset_tmp;
	unsigned int		amount;
	unsigned int		partial_page;
	ssize_t			nread;

	/* Get the starting Logical Block Address and check that it's
	 * not too big */
	if (fsg->cmnd[0] == SC_READ_6)
		lba = (fsg->cmnd[1] << 16) | get_be16(&fsg->cmnd[2]);
	else {
		lba = get_be32(&fsg->cmnd[2]);

		/* We allow DPO (Disable Page Out = don't save data in the
		 * cache) and FUA (Force Unit Access = don't read from the
		 * cache), but we don't implement them. */
		if ((fsg->cmnd[1] & ~0x18) != 0) {
			curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
			return -EINVAL;
		}
	}
	if (lba >= curlun->num_sectors) {
		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
		return -EINVAL;
	}
	file_offset = ((loff_t) lba) << 9;

	/* Carry out the file reads */
	amount_left = fsg->data_size_from_cmnd;
	if (unlikely(amount_left == 0))
		return -EIO;		// No default reply

	for (;;) {

		/* Figure out how much we need to read:
		 * Try to read the remaining amount.
		 * But don't read more than the buffer size.
		 * And don't try to read past the end of the file.
		 * Finally, if we're not at a page boundary, don't read past
		 *	the next page.
		 * If this means reading 0 then we were asked to read past
		 *	the end of file. */
		amount = min((unsigned int) amount_left, mod_data.buflen);
		amount = min((loff_t) amount,
				curlun->file_length - file_offset);
		partial_page = file_offset & (PAGE_CACHE_SIZE - 1);
		if (partial_page > 0)
			amount = min(amount, (unsigned int) PAGE_CACHE_SIZE -
					partial_page);

		/* Wait for the next buffer to become available */
		bh = fsg->next_buffhd_to_fill;
		while (bh->state != BUF_STATE_EMPTY) {
			rc = sleep_thread(fsg);
			if (rc)
				return rc;
		}

		/* If we were asked to read past the end of file,
		 * end with an empty buffer. */
		if (amount == 0) {
			curlun->sense_data =
					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
			curlun->sense_data_info = file_offset >> 9;
			curlun->info_valid = 1;
			bh->inreq->length = 0;
			bh->state = BUF_STATE_FULL;
			break;
		}

		/* Perform the read */
		file_offset_tmp = file_offset;
		nread = vfs_read(curlun->filp,
				(char __user *) bh->buf,
				amount, &file_offset_tmp);
		VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
				(unsigned long long) file_offset,
				(int) nread);
		if (signal_pending(current))
			return -EINTR;

		if (nread < 0) {
			LDBG(curlun, "error in file read: %d\n",
					(int) nread);
			nread = 0;
		} else if (nread < amount) {
			LDBG(curlun, "partial file read: %d/%u\n",
					(int) nread, amount);
			nread -= (nread & 511);	// Round down to a block
		}
		file_offset  += nread;
		amount_left  -= nread;
		fsg->residue -= nread;
		bh->inreq->length = nread;
		bh->state = BUF_STATE_FULL;

		/* If an error occurred, report it and its position */
		if (nread < amount) {
			curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
			curlun->sense_data_info = file_offset >> 9;
			curlun->info_valid = 1;
			break;
		}

		if (amount_left == 0)
			break;		// No more left to read

		/* Send this buffer and go read some more */
		bh->inreq->zero = 0;
		start_transfer(fsg, fsg->bulk_in, bh->inreq,
				&bh->inreq_busy, &bh->state);
		fsg->next_buffhd_to_fill = bh->next;
	}

	return -EIO;		// No default reply
}


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

static int do_write(struct fsg_dev *fsg)
{
	struct lun		*curlun = fsg->curlun;
	u32			lba;
	struct fsg_buffhd	*bh;
	int			get_some_more;
	u32			amount_left_to_req, amount_left_to_write;
	loff_t			usb_offset, file_offset, file_offset_tmp;
	unsigned int		amount;
	unsigned int		partial_page;
	ssize_t			nwritten;
	int			rc;

	if (curlun->ro) {
		curlun->sense_data = SS_WRITE_PROTECTED;
		return -EINVAL;
	}
	curlun->filp->f_flags &= ~O_SYNC;	// Default is not to wait

	/* Get the starting Logical Block Address and check that it's
	 * not too big */
	if (fsg->cmnd[0] == SC_WRITE_6)
		lba = (fsg->cmnd[1] << 16) | get_be16(&fsg->cmnd[2]);
	else {
		lba = get_be32(&fsg->cmnd[2]);

		/* We allow DPO (Disable Page Out = don't save data in the
		 * cache) and FUA (Force Unit Access = write directly to the
		 * medium).  We don't implement DPO; we implement FUA by
		 * performing synchronous output. */
		if ((fsg->cmnd[1] & ~0x18) != 0) {
			curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
			return -EINVAL;
		}
		if (fsg->cmnd[1] & 0x08)	// FUA
			curlun->filp->f_flags |= O_SYNC;
	}
	if (lba >= curlun->num_sectors) {
		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
		return -EINVAL;
	}

	/* Carry out the file writes */
	get_some_more = 1;
	file_offset = usb_offset = ((loff_t) lba) << 9;
	amount_left_to_req = amount_left_to_write = fsg->data_size_from_cmnd;

	while (amount_left_to_write > 0) {

		/* Queue a request for more data from the host */
		bh = fsg->next_buffhd_to_fill;
		if (bh->state == BUF_STATE_EMPTY && get_some_more) {

			/* Figure out how much we want to get:
			 * Try to get the remaining amount.
			 * But don't get more than the buffer size.
			 * And don't try to go past the end of the file.
			 * If we're not at a page boundary,
			 *	don't go past the next page.
			 * If this means getting 0, then we were asked
			 *	to write past the end of file.
			 * Finally, round down to a block boundary. */
			amount = min(amount_left_to_req, mod_data.buflen);
			amount = min((loff_t) amount, curlun->file_length -
					usb_offset);
			partial_page = usb_offset & (PAGE_CACHE_SIZE - 1);
			if (partial_page > 0)
				amount = min(amount,
	(unsigned int) PAGE_CACHE_SIZE - partial_page);

			if (amount == 0) {
				get_some_more = 0;
				curlun->sense_data =
					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
				curlun->sense_data_info = usb_offset >> 9;
				curlun->info_valid = 1;
				continue;
			}
			amount -= (amount & 511);
			if (amount == 0) {

				/* Why were we were asked to transfer a
				 * partial block? */
				get_some_more = 0;
				continue;
			}

			/* Get the next buffer */
			usb_offset += amount;
			fsg->usb_amount_left -= amount;
			amount_left_to_req -= amount;
			if (amount_left_to_req == 0)
				get_some_more = 0;

			/* amount is always divisible by 512, hence by
			 * the bulk-out maxpacket size */
			bh->outreq->length = bh->bulk_out_intended_length =
					amount;
			bh->outreq->short_not_ok = 1;
			start_transfer(fsg, fsg->bulk_out, bh->outreq,
					&bh->outreq_busy, &bh->state);
			fsg->next_buffhd_to_fill = bh->next;
			continue;
		}

		/* Write the received data to the backing file */
		bh = fsg->next_buffhd_to_drain;
		if (bh->state == BUF_STATE_EMPTY && !get_some_more)
			break;			// We stopped early
		if (bh->state == BUF_STATE_FULL) {
			smp_rmb();
			fsg->next_buffhd_to_drain = bh->next;
			bh->state = BUF_STATE_EMPTY;

			/* Did something go wrong with the transfer? */
			if (bh->outreq->status != 0) {
				curlun->sense_data = SS_COMMUNICATION_FAILURE;
				curlun->sense_data_info = file_offset >> 9;
				curlun->info_valid = 1;
				break;
			}

			amount = bh->outreq->actual;
			if (curlun->file_length - file_offset < amount) {
				LERROR(curlun,
	"write %u @ %llu beyond end %llu\n",
	amount, (unsigned long long) file_offset,
	(unsigned long long) curlun->file_length);
				amount = curlun->file_length - file_offset;
			}

			/* Perform the write */
			file_offset_tmp = file_offset;
			nwritten = vfs_write(curlun->filp,
					(char __user *) bh->buf,
					amount, &file_offset_tmp);
			VLDBG(curlun, "file write %u @ %llu -> %d\n", amount,
					(unsigned long long) file_offset,
					(int) nwritten);
			if (signal_pending(current))
				return -EINTR;		// Interrupted!

			if (nwritten < 0) {
				LDBG(curlun, "error in file write: %d\n",
						(int) nwritten);
				nwritten = 0;
			} else if (nwritten < amount) {
				LDBG(curlun, "partial file write: %d/%u\n",
						(int) nwritten, amount);
				nwritten -= (nwritten & 511);
						// Round down to a block
			}
			file_offset += nwritten;
			amount_left_to_write -= nwritten;
			fsg->residue -= nwritten;

			/* If an error occurred, report it and its position */
			if (nwritten < amount) {
				curlun->sense_data = SS_WRITE_ERROR;
				curlun->sense_data_info = file_offset >> 9;
				curlun->info_valid = 1;
				break;
			}

			/* Did the host decide to stop early? */
			if (bh->outreq->actual != bh->outreq->length) {
				fsg->short_packet_received = 1;
				break;
			}
			continue;
		}

		/* Wait for something to happen */
		rc = sleep_thread(fsg);
		if (rc)
			return rc;
	}

	return -EIO;		// No default reply
}


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

/* Sync the file data, don't bother with the metadata.
 * This code was copied from fs/buffer.c:sys_fdatasync(). */
static int fsync_sub(struct lun *curlun)
{
	struct file	*filp = curlun->filp;
	struct inode	*inode;
	int		rc, err;

	if (curlun->ro || !filp)
		return 0;
	if (!filp->f_op->fsync)
		return -EINVAL;

	inode = filp->f_path.dentry->d_inode;
	mutex_lock(&inode->i_mutex);
	rc = filemap_fdatawrite(inode->i_mapping);
	err = filp->f_op->fsync(filp, filp->f_path.dentry, 1);
	if (!rc)
		rc = err;
	err = filemap_fdatawait(inode->i_mapping);
	if (!rc)
		rc = err;
	mutex_unlock(&inode->i_mutex);
	VLDBG(curlun, "fdatasync -> %d\n", rc);
	return rc;
}

static void fsync_all(struct fsg_dev *fsg)
{
	int	i;

	for (i = 0; i < fsg->nluns; ++i)
		fsync_sub(&fsg->luns[i]);
}

static int do_synchronize_cache(struct fsg_dev *fsg)
{
	struct lun	*curlun = fsg->curlun;
	int		rc;

	/* We ignore the requested LBA and write out all file's
	 * dirty data buffers. */
	rc = fsync_sub(curlun);
	if (rc)
		curlun->sense_data = SS_WRITE_ERROR;
	return 0;
}


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

static void invalidate_sub(struct lun *curlun)
{
	struct file	*filp = curlun->filp;
	struct inode	*inode = filp->f_path.dentry->d_inode;
	unsigned long	rc;

	rc = invalidate_mapping_pages(inode->i_mapping, 0, -1);
	VLDBG(curlun, "invalidate_inode_pages -> %ld\n", rc);
}

static int do_verify(struct fsg_dev *fsg)
{
	struct lun		*curlun = fsg->curlun;
	u32			lba;
	u32			verification_length;
	struct fsg_buffhd	*bh = fsg->next_buffhd_to_fill;
	loff_t			file_offset, file_offset_tmp;
	u32			amount_left;
	unsigned int		amount;
	ssize_t			nread;

	/* Get the starting Logical Block Address and check that it's
	 * not too big */
	lba = get_be32(&fsg->cmnd[2]);
	if (lba >= curlun->num_sectors) {
		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
		return -EINVAL;
	}

	/* We allow DPO (Disable Page Out = don't save data in the
	 * cache) but we don't implement it. */
	if ((fsg->cmnd[1] & ~0x10) != 0) {
		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
		return -EINVAL;
	}

	verification_length = get_be16(&fsg->cmnd[7]);
	if (unlikely(verification_length == 0))
		return -EIO;		// No default reply

	/* Prepare to carry out the file verify */
	amount_left = verification_length << 9;
	file_offset = ((loff_t) lba) << 9;

	/* Write out all the dirty buffers before invalidating them */
	fsync_sub(curlun);
	if (signal_pending(current))
		return -EINTR;

	invalidate_sub(curlun);
	if (signal_pending(current))
		return -EINTR;

	/* Just try to read the requested blocks */
	while (amount_left > 0) {

		/* Figure out how much we need to read:
		 * Try to read the remaining amount, but not more than
		 * the buffer size.
		 * And don't try to read past the end of the file.
		 * If this means reading 0 then we were asked to read
		 * past the end of file. */
		amount = min((unsigned int) amount_left, mod_data.buflen);
		amount = min((loff_t) amount,
				curlun->file_length - file_offset);
		if (amount == 0) {
			curlun->sense_data =
					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
			curlun->sense_data_info = file_offset >> 9;
			curlun->info_valid = 1;
			break;
		}

		/* Perform the read */
		file_offset_tmp = file_offset;
		nread = vfs_read(curlun->filp,
				(char __user *) bh->buf,
				amount, &file_offset_tmp);
		VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
				(unsigned long long) file_offset,
				(int) nread);
		if (signal_pending(current))
			return -EINTR;

		if (nread < 0) {
			LDBG(curlun, "error in file verify: %d\n",
					(int) nread);
			nread = 0;
		} else if (nread < amount) {
			LDBG(curlun, "partial file verify: %d/%u\n",
					(int) nread, amount);
			nread -= (nread & 511);	// Round down to a sector
		}
		if (nread == 0) {
			curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
			curlun->sense_data_info = file_offset >> 9;
			curlun->info_valid = 1;
			break;
		}
		file_offset += nread;
		amount_left -= nread;
	}
	return 0;
}


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

static int do_inquiry(struct fsg_dev *fsg, struct fsg_buffhd *bh)
{
	u8	*buf = (u8 *) bh->buf;

	static char vendor_id[] = "Linux   ";
	static char product_id[] = "File-Stor Gadget";

	if (!fsg->curlun) {		// Unsupported LUNs are okay
		fsg->bad_lun_okay = 1;
		memset(buf, 0, 36);
		buf[0] = 0x7f;		// Unsupported, no device-type
		return 36;
	}

	memset(buf, 0, 8);	// Non-removable, direct-access device
	if (mod_data.removable)
		buf[1] = 0x80;
	buf[2] = 2;		// ANSI SCSI level 2
	buf[3] = 2;		// SCSI-2 INQUIRY data format
	buf[4] = 31;		// Additional length
				// No special options
	sprintf(buf + 8, "%-8s%-16s%04x", vendor_id, product_id,
			mod_data.release);
	return 36;
}


static int do_request_sense(struct fsg_dev *fsg, struct fsg_buffhd *bh)
{
	struct lun	*curlun = fsg->curlun;
	u8		*buf = (u8 *) bh->buf;
	u32		sd, sdinfo;
	int		valid;

	/*
	 * From the SCSI-2 spec., section 7.9 (Unit attention condition):
	 *
	 * If a REQUEST SENSE command is received from an initiator
	 * with a pending unit attention condition (before the target
	 * generates the contingent allegiance condition), then the
	 * target shall either:
	 *   a) report any pending sense data and preserve the unit
	 *	attention condition on the logical unit, or,
	 *   b) report the unit attention condition, may discard any
	 *	pending sense data, and clear the unit attention
	 *	condition on the logical unit for that initiator.
	 *
	 * FSG normally uses option a); enable this code to use option b).
	 */
#if 0
	if (curlun && curlun->unit_attention_data != SS_NO_SENSE) {
		curlun->sense_data = curlun->unit_attention_data;
		curlun->unit_attention_data = SS_NO_SENSE;
	}
#endif

	if (!curlun) {		// Unsupported LUNs are okay
		fsg->bad_lun_okay = 1;
		sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
		sdinfo = 0;
		valid = 0;
	} else {
		sd = curlun->sense_data;
		sdinfo = curlun->sense_data_info;
		valid = curlun->info_valid << 7;
		curlun->sense_data = SS_NO_SENSE;
		curlun->sense_data_info = 0;
		curlun->info_valid = 0;
	}

	memset(buf, 0, 18);
	buf[0] = valid | 0x70;			// Valid, current error
	buf[2] = SK(sd);
	put_be32(&buf[3], sdinfo);		// Sense information
	buf[7] = 18 - 8;			// Additional sense length
	buf[12] = ASC(sd);
	buf[13] = ASCQ(sd);
	return 18;
}


static int do_read_capacity(struct fsg_dev *fsg, struct fsg_buffhd *bh)
{
	struct lun	*curlun = fsg->curlun;
	u32		lba = get_be32(&fsg->cmnd[2]);
	int		pmi = fsg->cmnd[8];
	u8		*buf = (u8 *) bh->buf;

	/* Check the PMI and LBA fields */
	if (pmi > 1 || (pmi == 0 && lba != 0)) {
		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
		return -EINVAL;
	}

	put_be32(&buf[0], curlun->num_sectors - 1);	// Max logical block
	put_be32(&buf[4], 512);				// Block length
	return 8;
}


static int do_mode_sense(struct fsg_dev *fsg, struct fsg_buffhd *bh)
{
	struct lun	*curlun = fsg->curlun;
	int		mscmnd = fsg->cmnd[0];
	u8		*buf = (u8 *) bh->buf;
	u8		*buf0 = buf;
	int		pc, page_code;
	int		changeable_values, all_pages;
	int		valid_page = 0;
	int		len, limit;

	if ((fsg->cmnd[1] & ~0x08) != 0) {		// Mask away DBD
		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
		return -EINVAL;
	}
	pc = fsg->cmnd[2] >> 6;
	page_code = fsg->cmnd[2] & 0x3f;
	if (pc == 3) {
		curlun->sense_data = SS_SAVING_PARAMETERS_NOT_SUPPORTED;
		return -EINVAL;
	}
	changeable_values = (pc == 1);
	all_pages = (page_code == 0x3f);

	/* Write the mode parameter header.  Fixed values are: default
	 * medium type, no cache control (DPOFUA), and no block descriptors.
	 * The only variable value is the WriteProtect bit.  We will fill in
	 * the mode data length later. */
	memset(buf, 0, 8);
	if (mscmnd == SC_MODE_SENSE_6) {
		buf[2] = (curlun->ro ? 0x80 : 0x00);		// WP, DPOFUA
		buf += 4;
		limit = 255;
	} else {			// SC_MODE_SENSE_10
		buf[3] = (curlun->ro ? 0x80 : 0x00);		// WP, DPOFUA
		buf += 8;
		limit = 65535;		// Should really be mod_data.buflen
	}

	/* No block descriptors */

	/* The mode pages, in numerical order.  The only page we support
	 * is the Caching page. */
	if (page_code == 0x08 || all_pages) {
		valid_page = 1;
		buf[0] = 0x08;		// Page code
		buf[1] = 10;		// Page length
		memset(buf+2, 0, 10);	// None of the fields are changeable

		if (!changeable_values) {
			buf[2] = 0x04;	// Write cache enable,
					// Read cache not disabled
					// No cache retention priorities
			put_be16(&buf[4], 0xffff);  // Don't disable prefetch
					// Minimum prefetch = 0
			put_be16(&buf[8], 0xffff);  // Maximum prefetch
			put_be16(&buf[10], 0xffff); // Maximum prefetch ceiling
		}
		buf += 12;
	}

	/* Check that a valid page was requested and the mode data length
	 * isn't too long. */
	len = buf - buf0;
	if (!valid_page || len > limit) {
		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
		return -EINVAL;
	}

	/*  Store the mode data length */
	if (mscmnd == SC_MODE_SENSE_6)
		buf0[0] = len - 1;
	else
		put_be16(buf0, len - 2);
	return len;
}


static int do_start_stop(struct fsg_dev *fsg)
{
	struct lun	*curlun = fsg->curlun;
	int		loej, start;

	if (!mod_data.removable) {
		curlun->sense_data = SS_INVALID_COMMAND;
		return -EINVAL;
	}

	// int immed = fsg->cmnd[1] & 0x01;
	loej = fsg->cmnd[4] & 0x02;
	start = fsg->cmnd[4] & 0x01;

#ifdef CONFIG_USB_FILE_STORAGE_TEST
	if ((fsg->cmnd[1] & ~0x01) != 0 ||		// Mask away Immed
			(fsg->cmnd[4] & ~0x03) != 0) {	// Mask LoEj, Start
		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
		return -EINVAL;
	}

	if (!start) {

		/* Are we allowed to unload the media? */
		if (curlun->prevent_medium_removal) {
			LDBG(curlun, "unload attempt prevented\n");
			curlun->sense_data = SS_MEDIUM_REMOVAL_PREVENTED;
			return -EINVAL;
		}
		if (loej) {		// Simulate an unload/eject
			up_read(&fsg->filesem);
			down_write(&fsg->filesem);
			close_backing_file(curlun);
			up_write(&fsg->filesem);
			down_read(&fsg->filesem);
		}
	} else {

		/* Our emulation doesn't support mounting; the medium is
		 * available for use as soon as it is loaded. */
		if (!backing_file_is_open(curlun)) {
			curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
			return -EINVAL;
		}
	}
#endif
	return 0;
}


static int do_prevent_allow(struct fsg_dev *fsg)
{
	struct lun	*curlun = fsg->curlun;
	int		prevent;

	if (!mod_data.removable) {
		curlun->sense_data = SS_INVALID_COMMAND;
		return -EINVAL;
	}

	prevent = fsg->cmnd[4] & 0x01;
	if ((fsg->cmnd[4] & ~0x01) != 0) {		// Mask away Prevent
		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
		return -EINVAL;
	}

	if (curlun->prevent_medium_removal && !prevent)
		fsync_sub(curlun);
	curlun->prevent_medium_removal = prevent;
	return 0;
}


static int do_read_format_capacities(struct fsg_dev *fsg,
			struct fsg_buffhd *bh)
{
	struct lun	*curlun = fsg->curlun;
	u8		*buf = (u8 *) bh->buf;

	buf[0] = buf[1] = buf[2] = 0;
	buf[3] = 8;		// Only the Current/Maximum Capacity Descriptor
	buf += 4;

	put_be32(&buf[0], curlun->num_sectors);		// Number of blocks
	put_be32(&buf[4], 512);				// Block length
	buf[4] = 0x02;					// Current capacity
	return 12;
}


static int do_mode_select(struct fsg_dev *fsg, struct fsg_buffhd *bh)
{
	struct lun	*curlun = fsg->curlun;

	/* We don't support MODE SELECT */
	curlun->sense_data = SS_INVALID_COMMAND;
	return -EINVAL;
}


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

static int halt_bulk_in_endpoint(struct fsg_dev *fsg)
{
	int	rc;

	rc = fsg_set_halt(fsg, fsg->bulk_in);
	if (rc == -EAGAIN)
		VDBG(fsg, "delayed bulk-in endpoint halt\n");
	while (rc != 0) {
		if (rc != -EAGAIN) {
			WARN(fsg, "usb_ep_set_halt -> %d\n", rc);
			rc = 0;
			break;
		}

		/* Wait for a short time and then try again */
		if (msleep_interruptible(100) != 0)
			return -EINTR;
		rc = usb_ep_set_halt(fsg->bulk_in);
	}
	return rc;
}

static int pad_with_zeros(struct fsg_dev *fsg)
{
	struct fsg_buffhd	*bh = fsg->next_buffhd_to_fill;
	u32			nkeep = bh->inreq->length;
	u32			nsend;
	int			rc;

	bh->state = BUF_STATE_EMPTY;		// For the first iteration
	fsg->usb_amount_left = nkeep + fsg->residue;
	while (fsg->usb_amount_left > 0) {

		/* Wait for the next buffer to be free */
		while (bh->state != BUF_STATE_EMPTY) {
			rc = sleep_thread(fsg);
			if (rc)
				return rc;
		}

		nsend = min(fsg->usb_amount_left, (u32) mod_data.buflen);
		memset(bh->buf + nkeep, 0, nsend - nkeep);
		bh->inreq->length = nsend;
		bh->inreq->zero = 0;
		start_transfer(fsg, fsg->bulk_in, bh->inreq,
				&bh->inreq_busy, &bh->state);
		bh = fsg->next_buffhd_to_fill = bh->next;
		fsg->usb_amount_left -= nsend;
		nkeep = 0;
	}
	return 0;
}

static int throw_away_data(struct fsg_dev *fsg)
{
	struct fsg_buffhd	*bh;
	u32			amount;
	int			rc;

	while ((bh = fsg->next_buffhd_to_drain)->state != BUF_STATE_EMPTY ||
			fsg->usb_amount_left > 0) {

		/* Throw away the data in a filled buffer */
		if (bh->state == BUF_STATE_FULL) {
			smp_rmb();
			bh->state = BUF_STATE_EMPTY;
			fsg->next_buffhd_to_drain = bh->next;

			/* A short packet or an error ends everything */
			if (bh->outreq->actual != bh->outreq->length ||
					bh->outreq->status != 0) {
				raise_exception(fsg, FSG_STATE_ABORT_BULK_OUT);
				return -EINTR;
			}
			continue;
		}

		/* Try to submit another request if we need one */
		bh = fsg->next_buffhd_to_fill;
		if (bh->state == BUF_STATE_EMPTY && fsg->usb_amount_left > 0) {
			amount = min(fsg->usb_amount_left,
					(u32) mod_data.buflen);

			/* amount is always divisible by 512, hence by
			 * the bulk-out maxpacket size */
			bh->outreq->length = bh->bulk_out_intended_length =
					amount;
			bh->outreq->short_not_ok = 1;
			start_transfer(fsg, fsg->bulk_out, bh->outreq,
					&bh->outreq_busy, &bh->state);
			fsg->next_buffhd_to_fill = bh->next;
			fsg->usb_amount_left -= amount;
			continue;
		}

		/* Otherwise wait for something to happen */
		rc = sleep_thread(fsg);
		if (rc)
			return rc;
	}
	return 0;
}


static int finish_reply(struct fsg_dev *fsg)
{
	struct fsg_buffhd	*bh = fsg->next_buffhd_to_fill;
	int			rc = 0;

	switch (fsg->data_dir) {
	case DATA_DIR_NONE:
		break;			// Nothing to send

	/* If we don't know whether the host wants to read or write,
	 * this must be CB or CBI with an unknown command.  We mustn't
	 * try to send or receive any data.  So stall both bulk pipes
	 * if we can and wait for a reset. */
	case DATA_DIR_UNKNOWN:
		if (mod_data.can_stall) {
			fsg_set_halt(fsg, fsg->bulk_out);
			rc = halt_bulk_in_endpoint(fsg);
		}
		break;

	/* All but the last buffer of data must have already been sent */
	case DATA_DIR_TO_HOST:
		if (fsg->data_size == 0)
			;		// Nothing to send

		/* If there's no residue, simply send the last buffer */
		else if (fsg->residue == 0) {
			bh->inreq->zero = 0;
			start_transfer(fsg, fsg->bulk_in, bh->inreq,
					&bh->inreq_busy, &bh->state);
			fsg->next_buffhd_to_fill = bh->next;
		}

		/* There is a residue.  For CB and CBI, simply mark the end
		 * of the data with a short packet.  However, if we are
		 * allowed to stall, there was no data at all (residue ==
		 * data_size), and the command failed (invalid LUN or
		 * sense data is set), then halt the bulk-in endpoint
		 * instead. */
		else if (!transport_is_bbb()) {
			if (mod_data.can_stall &&
					fsg->residue == fsg->data_size &&
	(!fsg->curlun || fsg->curlun->sense_data != SS_NO_SENSE)) {
				bh->state = BUF_STATE_EMPTY;
				rc = halt_bulk_in_endpoint(fsg);
			} else {
				bh->inreq->zero = 1;
				start_transfer(fsg, fsg->bulk_in, bh->inreq,
						&bh->inreq_busy, &bh->state);
				fsg->next_buffhd_to_fill = bh->next;
			}
		}

		/* For Bulk-only, if we're allowed to stall then send the
		 * short packet and halt the bulk-in endpoint.  If we can't
		 * stall, pad out the remaining data with 0's. */
		else {
			if (mod_data.can_stall) {
				bh->inreq->zero = 1;
				start_transfer(fsg, fsg->bulk_in, bh->inreq,
						&bh->inreq_busy, &bh->state);
				fsg->next_buffhd_to_fill = bh->next;
				rc = halt_bulk_in_endpoint(fsg);
			} else
				rc = pad_with_zeros(fsg);
		}
		break;

	/* We have processed all we want from the data the host has sent.
	 * There may still be outstanding bulk-out requests. */
	case DATA_DIR_FROM_HOST:
		if (fsg->residue == 0)
			;		// Nothing to receive

		/* Did the host stop sending unexpectedly early? */
		else if (fsg->short_packet_received) {
			raise_exception(fsg, FSG_STATE_ABORT_BULK_OUT);
			rc = -EINTR;
		}

		/* We haven't processed all the incoming data.  Even though
		 * we may be allowed to stall, doing so would cause a race.
		 * The controller may already have ACK'ed all the remaining
		 * bulk-out packets, in which case the host wouldn't see a
		 * STALL.  Not realizing the endpoint was halted, it wouldn't
		 * clear the halt -- leading to problems later on. */
#if 0
		else if (mod_data.can_stall) {
			fsg_set_halt(fsg, fsg->bulk_out);
			raise_exception(fsg, FSG_STATE_ABORT_BULK_OUT);
			rc = -EINTR;
		}
#endif

		/* We can't stall.  Read in the excess data and throw it
		 * all away. */
		else
			rc = throw_away_data(fsg);
		break;
	}
	return rc;
}


static int send_status(struct fsg_dev *fsg)
{
	struct lun		*curlun = fsg->curlun;
	struct fsg_buffhd	*bh;
	int			rc;
	u8			status = USB_STATUS_PASS;
	u32			sd, sdinfo = 0;

	/* Wait for the next buffer to become available */
	bh = fsg->next_buffhd_to_fill;
	while (bh->state != BUF_STATE_EMPTY) {
		rc = sleep_thread(fsg);
		if (rc)
			return rc;
	}

	if (curlun) {
		sd = curlun->sense_data;
		sdinfo = curlun->sense_data_info;
	} else if (fsg->bad_lun_okay)
		sd = SS_NO_SENSE;
	else
		sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;

	if (fsg->phase_error) {
		DBG(fsg, "sending phase-error status\n");
		status = USB_STATUS_PHASE_ERROR;
		sd = SS_INVALID_COMMAND;
	} else if (sd != SS_NO_SENSE) {
		DBG(fsg, "sending command-failure status\n");
		status = USB_STATUS_FAIL;
		VDBG(fsg, "  sense data: SK x%02x, ASC x%02x, ASCQ x%02x;"
				"  info x%x\n",
				SK(sd), ASC(sd), ASCQ(sd), sdinfo);
	}

	if (transport_is_bbb()) {
		struct bulk_cs_wrap	*csw = bh->buf;

		/* Store and send the Bulk-only CSW */
		csw->Signature = __constant_cpu_to_le32(USB_BULK_CS_SIG);
		csw->Tag = fsg->tag;
		csw->Residue = cpu_to_le32(fsg->residue);
		csw->Status = status;

		bh->inreq->length = USB_BULK_CS_WRAP_LEN;
		bh->inreq->zero = 0;
		start_transfer(fsg, fsg->bulk_in, bh->inreq,
				&bh->inreq_busy, &bh->state);

	} else if (mod_data.transport_type == USB_PR_CB) {

		/* Control-Bulk transport has no status phase! */
		return 0;

	} else {			// USB_PR_CBI
		struct interrupt_data	*buf = bh->buf;

		/* Store and send the Interrupt data.  UFI sends the ASC
		 * and ASCQ bytes.  Everything else sends a Type (which
		 * is always 0) and the status Value. */
		if (mod_data.protocol_type == USB_SC_UFI) {
			buf->bType = ASC(sd);
			buf->bValue = ASCQ(sd);
		} else {
			buf->bType = 0;
			buf->bValue = status;
		}
		fsg->intreq->length = CBI_INTERRUPT_DATA_LEN;

		fsg->intr_buffhd = bh;		// Point to the right buffhd
		fsg->intreq->buf = bh->inreq->buf;
		fsg->intreq->context = bh;
		start_transfer(fsg, fsg->intr_in, fsg->intreq,
				&fsg->intreq_busy, &bh->state);
	}

	fsg->next_buffhd_to_fill = bh->next;
	return 0;
}


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

/* Check whether the command is properly formed and whether its data size
 * and direction agree with the values we already have. */
static int check_command(struct fsg_dev *fsg, int cmnd_size,
		enum data_direction data_dir, unsigned int mask,
		int needs_medium, const char *name)
{
	int			i;
	int			lun = fsg->cmnd[1] >> 5;
	static const char	dirletter[4] = {'u', 'o', 'i', 'n'};
	char			hdlen[20];
	struct lun		*curlun;

	/* Adjust the expected cmnd_size for protocol encapsulation padding.
	 * Transparent SCSI doesn't pad. */
	if (protocol_is_scsi())
		;

	/* There's some disagreement as to whether RBC pads commands or not.
	 * We'll play it safe and accept either form. */
	else if (mod_data.protocol_type == USB_SC_RBC) {
		if (fsg->cmnd_size == 12)
			cmnd_size = 12;

	/* All the other protocols pad to 12 bytes */
	} else
		cmnd_size = 12;

	hdlen[0] = 0;
	if (fsg->data_dir != DATA_DIR_UNKNOWN)
		sprintf(hdlen, ", H%c=%u", dirletter[(int) fsg->data_dir],
				fsg->data_size);
	VDBG(fsg, "SCSI command: %s;  Dc=%d, D%c=%u;  Hc=%d%s\n",
			name, cmnd_size, dirletter[(int) data_dir],
			fsg->data_size_from_cmnd, fsg->cmnd_size, hdlen);

	/* We can't reply at all until we know the correct data direction
	 * and size. */
	if (fsg->data_size_from_cmnd == 0)
		data_dir = DATA_DIR_NONE;
	if (fsg->data_dir == DATA_DIR_UNKNOWN) {	// CB or CBI
		fsg->data_dir = data_dir;
		fsg->data_size = fsg->data_size_from_cmnd;

	} else {					// Bulk-only
		if (fsg->data_size < fsg->data_size_from_cmnd) {

			/* Host data size < Device data size is a phase error.
			 * Carry out the command, but only transfer as much
			 * as we are allowed. */
			fsg->data_size_from_cmnd = fsg->data_size;
			fsg->phase_error = 1;
		}
	}
	fsg->residue = fsg->usb_amount_left = fsg->data_size;

	/* Conflicting data directions is a phase error */
	if (fsg->data_dir != data_dir && fsg->data_size_from_cmnd > 0) {
		fsg->phase_error = 1;
		return -EINVAL;
	}

	/* Verify the length of the command itself */
	if (cmnd_size != fsg->cmnd_size) {

		/* Special case workaround: MS-Windows issues REQUEST SENSE
		 * with cbw->Length == 12 (it should be 6). */
		if (fsg->cmnd[0] == SC_REQUEST_SENSE && fsg->cmnd_size == 12)
			cmnd_size = fsg->cmnd_size;
		else {
			fsg->phase_error = 1;
			return -EINVAL;
		}
	}

	/* Check that the LUN values are consistent */
	if (transport_is_bbb()) {
		if (fsg->lun != lun)
			DBG(fsg, "using LUN %d from CBW, "
					"not LUN %d from CDB\n",
					fsg->lun, lun);
	} else
		fsg->lun = lun;		// Use LUN from the command

	/* Check the LUN */
	if (fsg->lun >= 0 && fsg->lun < fsg->nluns) {
		fsg->curlun = curlun = &fsg->luns[fsg->lun];
		if (fsg->cmnd[0] != SC_REQUEST_SENSE) {
			curlun->sense_data = SS_NO_SENSE;
			curlun->sense_data_info = 0;
			curlun->info_valid = 0;
		}
	} else {
		fsg->curlun = curlun = NULL;
		fsg->bad_lun_okay = 0;

		/* INQUIRY and REQUEST SENSE commands are explicitly allowed
		 * to use unsupported LUNs; all others may not. */
		if (fsg->cmnd[0] != SC_INQUIRY &&
				fsg->cmnd[0] != SC_REQUEST_SENSE) {
			DBG(fsg, "unsupported LUN %d\n", fsg->lun);
			return -EINVAL;
		}
	}

	/* If a unit attention condition exists, only INQUIRY and
	 * REQUEST SENSE commands are allowed; anything else must fail. */
	if (curlun && curlun->unit_attention_data != SS_NO_SENSE &&
			fsg->cmnd[0] != SC_INQUIRY &&
			fsg->cmnd[0] != SC_REQUEST_SENSE) {
		curlun->sense_data = curlun->unit_attention_data;
		curlun->unit_attention_data = SS_NO_SENSE;
		return -EINVAL;
	}

	/* Check that only command bytes listed in the mask are non-zero */
	fsg->cmnd[1] &= 0x1f;			// Mask away the LUN
	for (i = 1; i < cmnd_size; ++i) {
		if (fsg->cmnd[i] && !(mask & (1 << i))) {
			if (curlun)
				curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
			return -EINVAL;
		}
	}

	/* If the medium isn't mounted and the command needs to access
	 * it, return an error. */
	if (curlun && !backing_file_is_open(curlun) && needs_medium) {
		curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
		return -EINVAL;
	}

	return 0;
}


static int do_scsi_command(struct fsg_dev *fsg)
{
	struct fsg_buffhd	*bh;
	int			rc;
	int			reply = -EINVAL;
	int			i;
	static char		unknown[16];

	dump_cdb(fsg);

	/* Wait for the next buffer to become available for data or status */
	bh = fsg->next_buffhd_to_drain = fsg->next_buffhd_to_fill;
	while (bh->state != BUF_STATE_EMPTY) {
		rc = sleep_thread(fsg);
		if (rc)
			return rc;
	}
	fsg->phase_error = 0;
	fsg->short_packet_received = 0;

	down_read(&fsg->filesem);	// We're using the backing file
	switch (fsg->cmnd[0]) {

	case SC_INQUIRY:
		fsg->data_size_from_cmnd = fsg->cmnd[4];
		if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
				(1<<4), 0,
				"INQUIRY")) == 0)
			reply = do_inquiry(fsg, bh);
		break;

	case SC_MODE_SELECT_6:
		fsg->data_size_from_cmnd = fsg->cmnd[4];
		if ((reply = check_command(fsg, 6, DATA_DIR_FROM_HOST,
				(1<<1) | (1<<4), 0,
				"MODE SELECT(6)")) == 0)
			reply = do_mode_select(fsg, bh);
		break;

	case SC_MODE_SELECT_10:
		fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
		if ((reply = check_command(fsg, 10, DATA_DIR_FROM_HOST,
				(1<<1) | (3<<7), 0,
				"MODE SELECT(10)")) == 0)
			reply = do_mode_select(fsg, bh);
		break;

	case SC_MODE_SENSE_6:
		fsg->data_size_from_cmnd = fsg->cmnd[4];
		if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
				(1<<1) | (1<<2) | (1<<4), 0,
				"MODE SENSE(6)")) == 0)
			reply = do_mode_sense(fsg, bh);
		break;

	case SC_MODE_SENSE_10:
		fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
		if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
				(1<<1) | (1<<2) | (3<<7), 0,
				"MODE SENSE(10)")) == 0)
			reply = do_mode_sense(fsg, bh);
		break;

	case SC_PREVENT_ALLOW_MEDIUM_REMOVAL:
		fsg->data_size_from_cmnd = 0;
		if ((reply = check_command(fsg, 6, DATA_DIR_NONE,
				(1<<4), 0,
				"PREVENT-ALLOW MEDIUM REMOVAL")) == 0)
			reply = do_prevent_allow(fsg);
		break;

	case SC_READ_6:
		i = fsg->cmnd[4];
		fsg->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
		if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
				(7<<1) | (1<<4), 1,
				"READ(6)")) == 0)
			reply = do_read(fsg);
		break;

	case SC_READ_10:
		fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]) << 9;
		if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
				(1<<1) | (0xf<<2) | (3<<7), 1,
				"READ(10)")) == 0)
			reply = do_read(fsg);
		break;

	case SC_READ_12:
		fsg->data_size_from_cmnd = get_be32(&fsg->cmnd[6]) << 9;
		if ((reply = check_command(fsg, 12, DATA_DIR_TO_HOST,
				(1<<1) | (0xf<<2) | (0xf<<6), 1,
				"READ(12)")) == 0)
			reply = do_read(fsg);
		break;

	case SC_READ_CAPACITY:
		fsg->data_size_from_cmnd = 8;
		if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
				(0xf<<2) | (1<<8), 1,
				"READ CAPACITY")) == 0)
			reply = do_read_capacity(fsg, bh);
		break;

	case SC_READ_FORMAT_CAPACITIES:
		fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
		if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
				(3<<7), 1,
				"READ FORMAT CAPACITIES")) == 0)
			reply = do_read_format_capacities(fsg, bh);
		break;

	case SC_REQUEST_SENSE:
		fsg->data_size_from_cmnd = fsg->cmnd[4];
		if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
				(1<<4), 0,
				"REQUEST SENSE")) == 0)
			reply = do_request_sense(fsg, bh);
		break;

	case SC_START_STOP_UNIT:
		fsg->data_size_from_cmnd = 0;
		if ((reply = check_command(fsg, 6, DATA_DIR_NONE,
				(1<<1) | (1<<4), 0,
				"START-STOP UNIT")) == 0)
			reply = do_start_stop(fsg);
		break;

	case SC_SYNCHRONIZE_CACHE:
		fsg->data_size_from_cmnd = 0;
		if ((reply = check_command(fsg, 10, DATA_DIR_NONE,
				(0xf<<2) | (3<<7), 1,
				"SYNCHRONIZE CACHE")) == 0)
			reply = do_synchronize_cache(fsg);
		break;

	case SC_TEST_UNIT_READY:
		fsg->data_size_from_cmnd = 0;
		reply = check_command(fsg, 6, DATA_DIR_NONE,
				0, 1,
				"TEST UNIT READY");
		break;

	/* Although optional, this command is used by MS-Windows.  We
	 * support a minimal version: BytChk must be 0. */
	case SC_VERIFY:
		fsg->data_size_from_cmnd = 0;
		if ((reply = check_command(fsg, 10, DATA_DIR_NONE,
				(1<<1) | (0xf<<2) | (3<<7), 1,
				"VERIFY")) == 0)
			reply = do_verify(fsg);
		break;

	case SC_WRITE_6:
		i = fsg->cmnd[4];
		fsg->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
		if ((reply = check_command(fsg, 6, DATA_DIR_FROM_HOST,
				(7<<1) | (1<<4), 1,
				"WRITE(6)")) == 0)
			reply = do_write(fsg);
		break;

	case SC_WRITE_10:
		fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]) << 9;
		if ((reply = check_command(fsg, 10, DATA_DIR_FROM_HOST,
				(1<<1) | (0xf<<2) | (3<<7), 1,
				"WRITE(10)")) == 0)
			reply = do_write(fsg);
		break;

	case SC_WRITE_12:
		fsg->data_size_from_cmnd = get_be32(&fsg->cmnd[6]) << 9;
		if ((reply = check_command(fsg, 12, DATA_DIR_FROM_HOST,
				(1<<1) | (0xf<<2) | (0xf<<6), 1,
				"WRITE(12)")) == 0)
			reply = do_write(fsg);
		break;

	/* Some mandatory commands that we recognize but don't implement.
	 * They don't mean much in this setting.  It's left as an exercise
	 * for anyone interested to implement RESERVE and RELEASE in terms
	 * of Posix locks. */
	case SC_FORMAT_UNIT:
	case SC_RELEASE:
	case SC_RESERVE:
	case SC_SEND_DIAGNOSTIC:
		// Fall through

	default:
		fsg->data_size_from_cmnd = 0;
		sprintf(unknown, "Unknown x%02x", fsg->cmnd[0]);
		if ((reply = check_command(fsg, fsg->cmnd_size,
				DATA_DIR_UNKNOWN, 0xff, 0, unknown)) == 0) {
			fsg->curlun->sense_data = SS_INVALID_COMMAND;
			reply = -EINVAL;
		}
		break;
	}
	up_read(&fsg->filesem);

	if (reply == -EINTR || signal_pending(current))
		return -EINTR;

	/* Set up the single reply buffer for finish_reply() */
	if (reply == -EINVAL)
		reply = 0;		// Error reply length
	if (reply >= 0 && fsg->data_dir == DATA_DIR_TO_HOST) {
		reply = min((u32) reply, fsg->data_size_from_cmnd);
		bh->inreq->length = reply;
		bh->state = BUF_STATE_FULL;
		fsg->residue -= reply;
	}				// Otherwise it's already set

	return 0;
}


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

static int received_cbw(struct fsg_dev *fsg, struct fsg_buffhd *bh)
{
	struct usb_request	*req = bh->outreq;
	struct bulk_cb_wrap	*cbw = req->buf;

	/* Was this a real packet? */
	if (req->status)
		return -EINVAL;

	/* Is the CBW valid? */
	if (req->actual != USB_BULK_CB_WRAP_LEN ||
			cbw->Signature != __constant_cpu_to_le32(
				USB_BULK_CB_SIG)) {
		DBG(fsg, "invalid CBW: len %u sig 0x%x\n",
				req->actual,
				le32_to_cpu(cbw->Signature));

		/* The Bulk-only spec says we MUST stall the bulk pipes!
		 * If we want to avoid stalls, set a flag so that we will
		 * clear the endpoint halts at the next reset. */
		if (!mod_data.can_stall)
			set_bit(CLEAR_BULK_HALTS, &fsg->atomic_bitflags);
		fsg_set_halt(fsg, fsg->bulk_out);
		halt_bulk_in_endpoint(fsg);
		return -EINVAL;
	}

	/* Is the CBW meaningful? */
	if (cbw->Lun >= MAX_LUNS || cbw->Flags & ~USB_BULK_IN_FLAG ||
			cbw->Length <= 0 || cbw->Length > MAX_COMMAND_SIZE) {
		DBG(fsg, "non-meaningful CBW: lun = %u, flags = 0x%x, "
				"cmdlen %u\n",
				cbw->Lun, cbw->Flags, cbw->Length);

		/* We can do anything we want here, so let's stall the
		 * bulk pipes if we are allowed to. */
		if (mod_data.can_stall) {
			fsg_set_halt(fsg, fsg->bulk_out);
			halt_bulk_in_endpoint(fsg);
		}
		return -EINVAL;
	}

	/* Save the command for later */
	fsg->cmnd_size = cbw->Length;
	memcpy(fsg->cmnd, cbw->CDB, fsg->cmnd_size);
	if (cbw->Flags & USB_BULK_IN_FLAG)
		fsg->data_dir = DATA_DIR_TO_HOST;
	else
		fsg->data_dir = DATA_DIR_FROM_HOST;
	fsg->data_size = le32_to_cpu(cbw->DataTransferLength);
	if (fsg->data_size == 0)
		fsg->data_dir = DATA_DIR_NONE;
	fsg->lun = cbw->Lun;
	fsg->tag = cbw->Tag;
	return 0;
}


static int get_next_command(struct fsg_dev *fsg)
{
	struct fsg_buffhd	*bh;
	int			rc = 0;

	if (transport_is_bbb()) {

		/* Wait for the next buffer to become available */
		bh = fsg->next_buffhd_to_fill;
		while (bh->state != BUF_STATE_EMPTY) {
			rc = sleep_thread(fsg);
			if (rc)
				return rc;
		}

		/* Queue a request to read a Bulk-only CBW */
		set_bulk_out_req_length(fsg, bh, USB_BULK_CB_WRAP_LEN);
		bh->outreq->short_not_ok = 1;
		start_transfer(fsg, fsg->bulk_out, bh->outreq,
				&bh->outreq_busy, &bh->state);

		/* We will drain the buffer in software, which means we
		 * can reuse it for the next filling.  No need to advance
		 * next_buffhd_to_fill. */

		/* Wait for the CBW to arrive */
		while (bh->state != BUF_STATE_FULL) {
			rc = sleep_thread(fsg);
			if (rc)
				return rc;
		}
		smp_rmb();
		rc = received_cbw(fsg, bh);
		bh->state = BUF_STATE_EMPTY;

	} else {		// USB_PR_CB or USB_PR_CBI

		/* Wait for the next command to arrive */
		while (fsg->cbbuf_cmnd_size == 0) {
			rc = sleep_thread(fsg);
			if (rc)
				return rc;
		}

		/* Is the previous status interrupt request still busy?
		 * The host is allowed to skip reading the status,
		 * so we must cancel it. */
		if (fsg->intreq_busy)
			usb_ep_dequeue(fsg->intr_in, fsg->intreq);

		/* Copy the command and mark the buffer empty */
		fsg->data_dir = DATA_DIR_UNKNOWN;
		spin_lock_irq(&fsg->lock);
		fsg->cmnd_size = fsg->cbbuf_cmnd_size;
		memcpy(fsg->cmnd, fsg->cbbuf_cmnd, fsg->cmnd_size);
		fsg->cbbuf_cmnd_size = 0;
		spin_unlock_irq(&fsg->lock);
	}
	return rc;
}


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

static int enable_endpoint(struct fsg_dev *fsg, struct usb_ep *ep,
		const struct usb_endpoint_descriptor *d)
{
	int	rc;

	ep->driver_data = fsg;
	rc = usb_ep_enable(ep, d);
	if (rc)
		ERROR(fsg, "can't enable %s, result %d\n", ep->name, rc);
	return rc;
}

static int alloc_request(struct fsg_dev *fsg, struct usb_ep *ep,
		struct usb_request **preq)
{
	*preq = usb_ep_alloc_request(ep, GFP_ATOMIC);
	if (*preq)
		return 0;
	ERROR(fsg, "can't allocate request for %s\n", ep->name);
	return -ENOMEM;
}

/*
 * Reset interface setting and re-init endpoint state (toggle etc).
 * Call with altsetting < 0 to disable the interface.  The only other
 * available altsetting is 0, which enables the interface.
 */
static int do_set_interface(struct fsg_dev *fsg, int altsetting)
{
	int	rc = 0;
	int	i;
	const struct usb_endpoint_descriptor	*d;

	if (fsg->running)
		DBG(fsg, "reset interface\n");

reset:
	/* Deallocate the requests */
	for (i = 0; i < NUM_BUFFERS; ++i) {
		struct fsg_buffhd *bh = &fsg->buffhds[i];

		if (bh->inreq) {
			usb_ep_free_request(fsg->bulk_in, bh->inreq);
			bh->inreq = NULL;
		}
		if (bh->outreq) {
			usb_ep_free_request(fsg->bulk_out, bh->outreq);
			bh->outreq = NULL;
		}
	}
	if (fsg->intreq) {
		usb_ep_free_request(fsg->intr_in, fsg->intreq);
		fsg->intreq = NULL;
	}

	/* Disable the endpoints */
	if (fsg->bulk_in_enabled) {
		usb_ep_disable(fsg->bulk_in);
		fsg->bulk_in_enabled = 0;
	}
	if (fsg->bulk_out_enabled) {
		usb_ep_disable(fsg->bulk_out);
		fsg->bulk_out_enabled = 0;
	}
	if (fsg->intr_in_enabled) {
		usb_ep_disable(fsg->intr_in);
		fsg->intr_in_enabled = 0;
	}

	fsg->running = 0;
	if (altsetting < 0 || rc != 0)
		return rc;

	DBG(fsg, "set interface %d\n", altsetting);

	/* Enable the endpoints */
	d = ep_desc(fsg->gadget, &fs_bulk_in_desc, &hs_bulk_in_desc);
	if ((rc = enable_endpoint(fsg, fsg->bulk_in, d)) != 0)
		goto reset;
	fsg->bulk_in_enabled = 1;

	d = ep_desc(fsg->gadget, &fs_bulk_out_desc, &hs_bulk_out_desc);
	if ((rc = enable_endpoint(fsg, fsg->bulk_out, d)) != 0)
		goto reset;
	fsg->bulk_out_enabled = 1;
	fsg->bulk_out_maxpacket = le16_to_cpu(d->wMaxPacketSize);

	if (transport_is_cbi()) {
		d = ep_desc(fsg->gadget, &fs_intr_in_desc, &hs_intr_in_desc);
		if ((rc = enable_endpoint(fsg, fsg->intr_in, d)) != 0)
			goto reset;
		fsg->intr_in_enabled = 1;
	}

	/* Allocate the requests */
	for (i = 0; i < NUM_BUFFERS; ++i) {
		struct fsg_buffhd	*bh = &fsg->buffhds[i];

		if ((rc = alloc_request(fsg, fsg->bulk_in, &bh->inreq)) != 0)
			goto reset;
		if ((rc = alloc_request(fsg, fsg->bulk_out, &bh->outreq)) != 0)
			goto reset;
		bh->inreq->buf = bh->outreq->buf = bh->buf;
		bh->inreq->context = bh->outreq->context = bh;
		bh->inreq->complete = bulk_in_complete;
		bh->outreq->complete = bulk_out_complete;
	}
	if (transport_is_cbi()) {
		if ((rc = alloc_request(fsg, fsg->intr_in, &fsg->intreq)) != 0)
			goto reset;
		fsg->intreq->complete = intr_in_complete;
	}

	fsg->running = 1;
	for (i = 0; i < fsg->nluns; ++i)
		fsg->luns[i].unit_attention_data = SS_RESET_OCCURRED;
	return rc;
}


/*
 * Change our operational configuration.  This code must agree with the code
 * that returns config descriptors, and with interface altsetting code.
 *
 * It's also responsible for power management interactions.  Some
 * configurations might not work with our current power sources.
 * For now we just assume the gadget is always self-powered.
 */
static int do_set_config(struct fsg_dev *fsg, u8 new_config)
{
	int	rc = 0;

	/* Disable the single interface */
	if (fsg->config != 0) {
		DBG(fsg, "reset config\n");
		fsg->config = 0;
		rc = do_set_interface(fsg, -1);
	}

	/* Enable the interface */
	if (new_config != 0) {
		fsg->config = new_config;
		if ((rc = do_set_interface(fsg, 0)) != 0)
			fsg->config = 0;	// Reset on errors
		else {
			char *speed;

			switch (fsg->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;
			}
			INFO(fsg, "%s speed config #%d\n", speed, fsg->config);
		}
	}
	return rc;
}


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

static void handle_exception(struct fsg_dev *fsg)
{
	siginfo_t		info;
	int			sig;
	int			i;
	int			num_active;
	struct fsg_buffhd	*bh;
	enum fsg_state		old_state;
	u8			new_config;
	struct lun		*curlun;
	unsigned int		exception_req_tag;
	int			rc;

	/* Clear the existing signals.  Anything but SIGUSR1 is converted
	 * into a high-priority EXIT exception. */
	for (;;) {
		sig = dequeue_signal_lock(current, &current->blocked, &info);
		if (!sig)
			break;
		if (sig != SIGUSR1) {
			if (fsg->state < FSG_STATE_EXIT)
				DBG(fsg, "Main thread exiting on signal\n");
			raise_exception(fsg, FSG_STATE_EXIT);
		}
	}

	/* Cancel all the pending transfers */
	if (fsg->intreq_busy)
		usb_ep_dequeue(fsg->intr_in, fsg->intreq);
	for (i = 0; i < NUM_BUFFERS; ++i) {
		bh = &fsg->buffhds[i];
		if (bh->inreq_busy)
			usb_ep_dequeue(fsg->bulk_in, bh->inreq);
		if (bh->outreq_busy)
			usb_ep_dequeue(fsg->bulk_out, bh->outreq);
	}

	/* Wait until everything is idle */
	for (;;) {
		num_active = fsg->intreq_busy;
		for (i = 0; i < NUM_BUFFERS; ++i) {
			bh = &fsg->buffhds[i];
			num_active += bh->inreq_busy + bh->outreq_busy;
		}
		if (num_active == 0)
			break;
		if (sleep_thread(fsg))
			return;
	}

	/* Clear out the controller's fifos */
	if (fsg->bulk_in_enabled)
		usb_ep_fifo_flush(fsg->bulk_in);
	if (fsg->bulk_out_enabled)
		usb_ep_fifo_flush(fsg->bulk_out);
	if (fsg->intr_in_enabled)
		usb_ep_fifo_flush(fsg->intr_in);

	/* Reset the I/O buffer states and pointers, the SCSI
	 * state, and the exception.  Then invoke the handler. */
	spin_lock_irq(&fsg->lock);

	for (i = 0; i < NUM_BUFFERS; ++i) {
		bh = &fsg->buffhds[i];
		bh->state = BUF_STATE_EMPTY;
	}
	fsg->next_buffhd_to_fill = fsg->next_buffhd_to_drain =
			&fsg->buffhds[0];

	exception_req_tag = fsg->exception_req_tag;
	new_config = fsg->new_config;
	old_state = fsg->state;

	if (old_state == FSG_STATE_ABORT_BULK_OUT)
		fsg->state = FSG_STATE_STATUS_PHASE;
	else {
		for (i = 0; i < fsg->nluns; ++i) {
			curlun = &fsg->luns[i];
			curlun->prevent_medium_removal = 0;
			curlun->sense_data = curlun->unit_attention_data =
					SS_NO_SENSE;
			curlun->sense_data_info = 0;
			curlun->info_valid = 0;
		}
		fsg->state = FSG_STATE_IDLE;
	}
	spin_unlock_irq(&fsg->lock);

	/* Carry out any extra actions required for the exception */
	switch (old_state) {
	default:
		break;

	case FSG_STATE_ABORT_BULK_OUT:
		send_status(fsg);
		spin_lock_irq(&fsg->lock);
		if (fsg->state == FSG_STATE_STATUS_PHASE)
			fsg->state = FSG_STATE_IDLE;
		spin_unlock_irq(&fsg->lock);
		break;

	case FSG_STATE_RESET:
		/* In case we were forced against our will to halt a
		 * bulk endpoint, clear the halt now.  (The SuperH UDC
		 * requires this.) */
		if (test_and_clear_bit(CLEAR_BULK_HALTS,
				&fsg->atomic_bitflags)) {
			usb_ep_clear_halt(fsg->bulk_in);
			usb_ep_clear_halt(fsg->bulk_out);
		}

		if (transport_is_bbb()) {
			if (fsg->ep0_req_tag == exception_req_tag)
				ep0_queue(fsg);	// Complete the status stage

		} else if (transport_is_cbi())
			send_status(fsg);	// Status by interrupt pipe

		/* Technically this should go here, but it would only be
		 * a waste of time.  Ditto for the INTERFACE_CHANGE and
		 * CONFIG_CHANGE cases. */
		// for (i = 0; i < fsg->nluns; ++i)
		//	fsg->luns[i].unit_attention_data = SS_RESET_OCCURRED;
		break;

	case FSG_STATE_INTERFACE_CHANGE:
		rc = do_set_interface(fsg, 0);
		if (fsg->ep0_req_tag != exception_req_tag)
			break;
		if (rc != 0)			// STALL on errors
			fsg_set_halt(fsg, fsg->ep0);
		else				// Complete the status stage
			ep0_queue(fsg);
		break;

	case FSG_STATE_CONFIG_CHANGE:
		rc = do_set_config(fsg, new_config);
		if (fsg->ep0_req_tag != exception_req_tag)
			break;
		if (rc != 0)			// STALL on errors
			fsg_set_halt(fsg, fsg->ep0);
		else				// Complete the status stage
			ep0_queue(fsg);
		break;

	case FSG_STATE_DISCONNECT:
		fsync_all(fsg);
		do_set_config(fsg, 0);		// Unconfigured state
		break;

	case FSG_STATE_EXIT:
	case FSG_STATE_TERMINATED:
		do_set_config(fsg, 0);			// Free resources
		spin_lock_irq(&fsg->lock);
		fsg->state = FSG_STATE_TERMINATED;	// Stop the thread
		spin_unlock_irq(&fsg->lock);
		break;
	}
}


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

static int fsg_main_thread(void *fsg_)
{
	struct fsg_dev		*fsg = fsg_;

	/* Allow the thread to be killed by a signal, but set the signal mask
	 * to block everything but INT, TERM, KILL, and USR1. */
	allow_signal(SIGINT);
	allow_signal(SIGTERM);
	allow_signal(SIGKILL);
	allow_signal(SIGUSR1);

	/* Allow the thread to be frozen */
	set_freezable();

	/* Arrange for userspace references to be interpreted as kernel
	 * pointers.  That way we can pass a kernel pointer to a routine
	 * that expects a __user pointer and it will work okay. */
	set_fs(get_ds());

	/* The main loop */
	while (fsg->state != FSG_STATE_TERMINATED) {
		if (exception_in_progress(fsg) || signal_pending(current)) {
			handle_exception(fsg);
			continue;
		}

		if (!fsg->running) {
			sleep_thread(fsg);
			continue;
		}

		if (get_next_command(fsg))
			continue;

		spin_lock_irq(&fsg->lock);
		if (!exception_in_progress(fsg))
			fsg->state = FSG_STATE_DATA_PHASE;
		spin_unlock_irq(&fsg->lock);

		if (do_scsi_command(fsg) || finish_reply(fsg))
			continue;

		spin_lock_irq(&fsg->lock);
		if (!exception_in_progress(fsg))
			fsg->state = FSG_STATE_STATUS_PHASE;
		spin_unlock_irq(&fsg->lock);

		if (send_status(fsg))
			continue;

		spin_lock_irq(&fsg->lock);
		if (!exception_in_progress(fsg))
			fsg->state = FSG_STATE_IDLE;
		spin_unlock_irq(&fsg->lock);
		}

	spin_lock_irq(&fsg->lock);
	fsg->thread_task = NULL;
	spin_unlock_irq(&fsg->lock);

	/* In case we are exiting because of a signal, unregister the
	 * gadget driver and close the backing file. */
	if (test_and_clear_bit(REGISTERED, &fsg->atomic_bitflags)) {
		usb_gadget_unregister_driver(&fsg_driver);
		close_all_backing_files(fsg);
	}

	/* Let the unbind and cleanup routines know the thread has exited */
	complete_and_exit(&fsg->thread_notifier, 0);
}


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

/* If the next two routines are called while the gadget is registered,
 * the caller must own fsg->filesem for writing. */

static int open_backing_file(struct lun *curlun, const char *filename)
{
	int				ro;
	struct file			*filp = NULL;
	int				rc = -EINVAL;
	struct inode			*inode = NULL;
	loff_t				size;
	loff_t				num_sectors;

	/* R/W if we can, R/O if we must */
	ro = curlun->ro;
	if (!ro) {
		filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
		if (-EROFS == PTR_ERR(filp))
			ro = 1;
	}
	if (ro)
		filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
	if (IS_ERR(filp)) {
		LINFO(curlun, "unable to open backing file: %s\n", filename);
		return PTR_ERR(filp);
	}

	if (!(filp->f_mode & FMODE_WRITE))
		ro = 1;

	if (filp->f_path.dentry)
		inode = filp->f_path.dentry->d_inode;
	if (inode && S_ISBLK(inode->i_mode)) {
		if (bdev_read_only(inode->i_bdev))
			ro = 1;
	} else if (!inode || !S_ISREG(inode->i_mode)) {
		LINFO(curlun, "invalid file type: %s\n", filename);
		goto out;
	}

	/* If we can't read the file, it's no good.
	 * If we can't write the file, use it read-only. */
	if (!filp->f_op || !(filp->f_op->read || filp->f_op->aio_read)) {
		LINFO(curlun, "file not readable: %s\n", filename);
		goto out;
	}
	if (!(filp->f_op->write || filp->f_op->aio_write))
		ro = 1;

	size = i_size_read(inode->i_mapping->host);
	if (size < 0) {
		LINFO(curlun, "unable to find file size: %s\n", filename);
		rc = (int) size;
		goto out;
	}
	num_sectors = size >> 9;	// File size in 512-byte sectors
	if (num_sectors == 0) {
		LINFO(curlun, "file too small: %s\n", filename);
		rc = -ETOOSMALL;
		goto out;
	}

	get_file(filp);
	curlun->ro = ro;
	curlun->filp = filp;
	curlun->file_length = size;
	curlun->num_sectors = num_sectors;
	LDBG(curlun, "open backing file: %s\n", filename);
	rc = 0;

out:
	filp_close(filp, current->files);
	return rc;
}


static void close_backing_file(struct lun *curlun)
{
	if (curlun->filp) {
		LDBG(curlun, "close backing file\n");
		fput(curlun->filp);
		curlun->filp = NULL;
	}
}

static void close_all_backing_files(struct fsg_dev *fsg)
{
	int	i;

	for (i = 0; i < fsg->nluns; ++i)
		close_backing_file(&fsg->luns[i]);
}


static ssize_t show_ro(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct lun	*curlun = dev_to_lun(dev);

	return sprintf(buf, "%d\n", curlun->ro);
}

static ssize_t show_file(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	struct lun	*curlun = dev_to_lun(dev);
	struct fsg_dev	*fsg = dev_get_drvdata(dev);
	char		*p;
	ssize_t		rc;

	down_read(&fsg->filesem);
	if (backing_file_is_open(curlun)) {	// Get the complete pathname
		p = d_path(&curlun->filp->f_path, buf, PAGE_SIZE - 1);
		if (IS_ERR(p))
			rc = PTR_ERR(p);
		else {
			rc = strlen(p);
			memmove(buf, p, rc);
			buf[rc] = '\n';		// Add a newline
			buf[++rc] = 0;
		}
	} else {				// No file, return 0 bytes
		*buf = 0;
		rc = 0;
	}
	up_read(&fsg->filesem);
	return rc;
}


static ssize_t store_ro(struct device *dev, struct device_attribute *attr,
		const char *buf, size_t count)
{
	ssize_t		rc = count;
	struct lun	*curlun = dev_to_lun(dev);
	struct fsg_dev	*fsg = dev_get_drvdata(dev);
	int		i;

	if (sscanf(buf, "%d", &i) != 1)
		return -EINVAL;

	/* Allow the write-enable status to change only while the backing file
	 * is closed. */
	down_read(&fsg->filesem);
	if (backing_file_is_open(curlun)) {
		LDBG(curlun, "read-only status change prevented\n");
		rc = -EBUSY;
	} else {
		curlun->ro = !!i;
		LDBG(curlun, "read-only status set to %d\n", curlun->ro);
	}
	up_read(&fsg->filesem);
	return rc;
}

static ssize_t store_file(struct device *dev, struct device_attribute *attr,
		const char *buf, size_t count)
{
	struct lun	*curlun = dev_to_lun(dev);
	struct fsg_dev	*fsg = dev_get_drvdata(dev);
	int		rc = 0;

	if (curlun->prevent_medium_removal && backing_file_is_open(curlun)) {
		LDBG(curlun, "eject attempt prevented\n");
		return -EBUSY;				// "Door is locked"
	}

	/* Remove a trailing newline */
	if (count > 0 && buf[count-1] == '\n')
		((char *) buf)[count-1] = 0;		// Ugh!

	/* Eject current medium */
	down_write(&fsg->filesem);
	if (backing_file_is_open(curlun)) {
		close_backing_file(curlun);
		curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
	}

	/* Load new medium */
	if (count > 0 && buf[0]) {
		rc = open_backing_file(curlun, buf);
		if (rc == 0)
			curlun->unit_attention_data =
					SS_NOT_READY_TO_READY_TRANSITION;
	}
	up_write(&fsg->filesem);
	return (rc < 0 ? rc : count);
}


/* The write permissions and store_xxx pointers are set in fsg_bind() */
static DEVICE_ATTR(ro, 0444, show_ro, NULL);
static DEVICE_ATTR(file, 0444, show_file, NULL);


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

static void fsg_release(struct kref *ref)
{
	struct fsg_dev	*fsg = container_of(ref, struct fsg_dev, ref);

	kfree(fsg->luns);
	kfree(fsg);
}

static void lun_release(struct device *dev)
{
	struct fsg_dev	*fsg = dev_get_drvdata(dev);

	kref_put(&fsg->ref, fsg_release);
}

static void /* __init_or_exit */ fsg_unbind(struct usb_gadget *gadget)
{
	struct fsg_dev		*fsg = get_gadget_data(gadget);
	int			i;
	struct lun		*curlun;
	struct usb_request	*req = fsg->ep0req;

	DBG(fsg, "unbind\n");
	clear_bit(REGISTERED, &fsg->atomic_bitflags);

	/* Unregister the sysfs attribute files and the LUNs */
	for (i = 0; i < fsg->nluns; ++i) {
		curlun = &fsg->luns[i];
		if (curlun->registered) {
			device_remove_file(&curlun->dev, &dev_attr_ro);
			device_remove_file(&curlun->dev, &dev_attr_file);
			device_unregister(&curlun->dev);
			curlun->registered = 0;
		}
	}

	/* If the thread isn't already dead, tell it to exit now */
	if (fsg->state != FSG_STATE_TERMINATED) {
		raise_exception(fsg, FSG_STATE_EXIT);
		wait_for_completion(&fsg->thread_notifier);

		/* The cleanup routine waits for this completion also */
		complete(&fsg->thread_notifier);
	}

	/* Free the data buffers */
	for (i = 0; i < NUM_BUFFERS; ++i)
		kfree(fsg->buffhds[i].buf);

	/* Free the request and buffer for endpoint 0 */
	if (req) {
		kfree(req->buf);
		usb_ep_free_request(fsg->ep0, req);
	}

	set_gadget_data(gadget, NULL);
}


static int __init check_parameters(struct fsg_dev *fsg)
{
	int	prot;
	int	gcnum;

	/* Store the default values */
	mod_data.transport_type = USB_PR_BULK;
	mod_data.transport_name = "Bulk-only";
	mod_data.protocol_type = USB_SC_SCSI;
	mod_data.protocol_name = "Transparent SCSI";

	if (gadget_is_sh(fsg->gadget))
		mod_data.can_stall = 0;

	if (mod_data.release == 0xffff) {	// Parameter wasn't set
		/* The sa1100 controller is not supported */
		if (gadget_is_sa1100(fsg->gadget))
			gcnum = -1;
		else
			gcnum = usb_gadget_controller_number(fsg->gadget);
		if (gcnum >= 0)
			mod_data.release = 0x0300 + gcnum;
		else {
			WARN(fsg, "controller '%s' not recognized\n",
				fsg->gadget->name);
			mod_data.release = 0x0399;
		}
	}

	prot = simple_strtol(mod_data.protocol_parm, NULL, 0);

#ifdef CONFIG_USB_FILE_STORAGE_TEST
	if (strnicmp(mod_data.transport_parm, "BBB", 10) == 0) {
		;		// Use default setting
	} else if (strnicmp(mod_data.transport_parm, "CB", 10) == 0) {
		mod_data.transport_type = USB_PR_CB;
		mod_data.transport_name = "Control-Bulk";
	} else if (strnicmp(mod_data.transport_parm, "CBI", 10) == 0) {
		mod_data.transport_type = USB_PR_CBI;
		mod_data.transport_name = "Control-Bulk-Interrupt";
	} else {
		ERROR(fsg, "invalid transport: %s\n", mod_data.transport_parm);
		return -EINVAL;
	}

	if (strnicmp(mod_data.protocol_parm, "SCSI", 10) == 0 ||
			prot == USB_SC_SCSI) {
		;		// Use default setting
	} else if (strnicmp(mod_data.protocol_parm, "RBC", 10) == 0 ||
			prot == USB_SC_RBC) {
		mod_data.protocol_type = USB_SC_RBC;
		mod_data.protocol_name = "RBC";
	} else if (strnicmp(mod_data.protocol_parm, "8020", 4) == 0 ||
			strnicmp(mod_data.protocol_parm, "ATAPI", 10) == 0 ||
			prot == USB_SC_8020) {
		mod_data.protocol_type = USB_SC_8020;
		mod_data.protocol_name = "8020i (ATAPI)";
	} else if (strnicmp(mod_data.protocol_parm, "QIC", 3) == 0 ||
			prot == USB_SC_QIC) {
		mod_data.protocol_type = USB_SC_QIC;
		mod_data.protocol_name = "QIC-157";
	} else if (strnicmp(mod_data.protocol_parm, "UFI", 10) == 0 ||
			prot == USB_SC_UFI) {
		mod_data.protocol_type = USB_SC_UFI;
		mod_data.protocol_name = "UFI";
	} else if (strnicmp(mod_data.protocol_parm, "8070", 4) == 0 ||
			prot == USB_SC_8070) {
		mod_data.protocol_type = USB_SC_8070;
		mod_data.protocol_name = "8070i";
	} else {
		ERROR(fsg, "invalid protocol: %s\n", mod_data.protocol_parm);
		return -EINVAL;
	}

	mod_data.buflen &= PAGE_CACHE_MASK;
	if (mod_data.buflen <= 0) {
		ERROR(fsg, "invalid buflen\n");
		return -ETOOSMALL;
	}
#endif /* CONFIG_USB_FILE_STORAGE_TEST */

	return 0;
}


static int __init fsg_bind(struct usb_gadget *gadget)
{
	struct fsg_dev		*fsg = the_fsg;
	int			rc;
	int			i;
	struct lun		*curlun;
	struct usb_ep		*ep;
	struct usb_request	*req;
	char			*pathbuf, *p;

	fsg->gadget = gadget;
	set_gadget_data(gadget, fsg);
	fsg->ep0 = gadget->ep0;
	fsg->ep0->driver_data = fsg;

	if ((rc = check_parameters(fsg)) != 0)
		goto out;

	if (mod_data.removable) {	// Enable the store_xxx attributes
		dev_attr_ro.attr.mode = dev_attr_file.attr.mode = 0644;
		dev_attr_ro.store = store_ro;
		dev_attr_file.store = store_file;
	}

	/* Find out how many LUNs there should be */
	i = mod_data.nluns;
	if (i == 0)
		i = max(mod_data.num_filenames, 1u);
	if (i > MAX_LUNS) {
		ERROR(fsg, "invalid number of LUNs: %d\n", i);
		rc = -EINVAL;
		goto out;
	}

	/* Create the LUNs, open their backing files, and register the
	 * LUN devices in sysfs. */
	fsg->luns = kzalloc(i * sizeof(struct lun), GFP_KERNEL);
	if (!fsg->luns) {
		rc = -ENOMEM;
		goto out;
	}
	fsg->nluns = i;

	for (i = 0; i < fsg->nluns; ++i) {
		curlun = &fsg->luns[i];
		curlun->ro = mod_data.ro[i];
		curlun->dev.release = lun_release;
		curlun->dev.parent = &gadget->dev;
		curlun->dev.driver = &fsg_driver.driver;
		dev_set_drvdata(&curlun->dev, fsg);
		snprintf(curlun->dev.bus_id, BUS_ID_SIZE,
				"%s-lun%d", gadget->dev.bus_id, i);

		if ((rc = device_register(&curlun->dev)) != 0) {
			INFO(fsg, "failed to register LUN%d: %d\n", i, rc);
			goto out;
		}
		if ((rc = device_create_file(&curlun->dev,
					&dev_attr_ro)) != 0 ||
				(rc = device_create_file(&curlun->dev,
					&dev_attr_file)) != 0) {
			device_unregister(&curlun->dev);
			goto out;
		}
		curlun->registered = 1;
		kref_get(&fsg->ref);

		if (mod_data.file[i] && *mod_data.file[i]) {
			if ((rc = open_backing_file(curlun,
					mod_data.file[i])) != 0)
				goto out;
		} else if (!mod_data.removable) {
			ERROR(fsg, "no file given for LUN%d\n", i);
			rc = -EINVAL;
			goto out;
		}
	}

	/* Find all the endpoints we will use */
	usb_ep_autoconfig_reset(gadget);
	ep = usb_ep_autoconfig(gadget, &fs_bulk_in_desc);
	if (!ep)
		goto autoconf_fail;
	ep->driver_data = fsg;		// claim the endpoint
	fsg->bulk_in = ep;

	ep = usb_ep_autoconfig(gadget, &fs_bulk_out_desc);
	if (!ep)
		goto autoconf_fail;
	ep->driver_data = fsg;		// claim the endpoint
	fsg->bulk_out = ep;

	if (transport_is_cbi()) {
		ep = usb_ep_autoconfig(gadget, &fs_intr_in_desc);
		if (!ep)
			goto autoconf_fail;
		ep->driver_data = fsg;		// claim the endpoint
		fsg->intr_in = ep;
	}

	/* Fix up the descriptors */
	device_desc.bMaxPacketSize0 = fsg->ep0->maxpacket;
	device_desc.idVendor = cpu_to_le16(mod_data.vendor);
	device_desc.idProduct = cpu_to_le16(mod_data.product);
	device_desc.bcdDevice = cpu_to_le16(mod_data.release);

	i = (transport_is_cbi() ? 3 : 2);	// Number of endpoints
	intf_desc.bNumEndpoints = i;
	intf_desc.bInterfaceSubClass = mod_data.protocol_type;
	intf_desc.bInterfaceProtocol = mod_data.transport_type;
	fs_function[i + FS_FUNCTION_PRE_EP_ENTRIES] = NULL;

	if (gadget_is_dualspeed(gadget)) {
		hs_function[i + HS_FUNCTION_PRE_EP_ENTRIES] = NULL;

		/* Assume ep0 uses the same maxpacket value for both speeds */
		dev_qualifier.bMaxPacketSize0 = fsg->ep0->maxpacket;

		/* Assume endpoint addresses are the same for both speeds */
		hs_bulk_in_desc.bEndpointAddress =
				fs_bulk_in_desc.bEndpointAddress;
		hs_bulk_out_desc.bEndpointAddress =
				fs_bulk_out_desc.bEndpointAddress;
		hs_intr_in_desc.bEndpointAddress =
				fs_intr_in_desc.bEndpointAddress;
	}

	if (gadget_is_otg(gadget))
		otg_desc.bmAttributes |= USB_OTG_HNP;

	rc = -ENOMEM;

	/* Allocate the request and buffer for endpoint 0 */
	fsg->ep0req = req = usb_ep_alloc_request(fsg->ep0, GFP_KERNEL);
	if (!req)
		goto out;
	req->buf = kmalloc(EP0_BUFSIZE, GFP_KERNEL);
	if (!req->buf)
		goto out;
	req->complete = ep0_complete;

	/* Allocate the data buffers */
	for (i = 0; i < NUM_BUFFERS; ++i) {
		struct fsg_buffhd	*bh = &fsg->buffhds[i];

		/* Allocate for the bulk-in endpoint.  We assume that
		 * the buffer will also work with the bulk-out (and
		 * interrupt-in) endpoint. */
		bh->buf = kmalloc(mod_data.buflen, GFP_KERNEL);
		if (!bh->buf)
			goto out;
		bh->next = bh + 1;
	}
	fsg->buffhds[NUM_BUFFERS - 1].next = &fsg->buffhds[0];

	/* This should reflect the actual gadget power source */
	usb_gadget_set_selfpowered(gadget);

	snprintf(manufacturer, sizeof manufacturer, "%s %s with %s",
			init_utsname()->sysname, init_utsname()->release,
			gadget->name);

	/* On a real device, serial[] would be loaded from permanent
	 * storage.  We just encode it from the driver version string. */
	for (i = 0; i < sizeof(serial) - 2; i += 2) {
		unsigned char		c = DRIVER_VERSION[i / 2];

		if (!c)
			break;
		sprintf(&serial[i], "%02X", c);
	}

	fsg->thread_task = kthread_create(fsg_main_thread, fsg,
			"file-storage-gadget");
	if (IS_ERR(fsg->thread_task)) {
		rc = PTR_ERR(fsg->thread_task);
		goto out;
	}

	INFO(fsg, DRIVER_DESC ", version: " DRIVER_VERSION "\n");
	INFO(fsg, "Number of LUNs=%d\n", fsg->nluns);

	pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
	for (i = 0; i < fsg->nluns; ++i) {
		curlun = &fsg->luns[i];
		if (backing_file_is_open(curlun)) {
			p = NULL;
			if (pathbuf) {
				p = d_path(&curlun->filp->f_path,
					   pathbuf, PATH_MAX);
				if (IS_ERR(p))
					p = NULL;
			}
			LINFO(curlun, "ro=%d, file: %s\n",
					curlun->ro, (p ? p : "(error)"));
		}
	}
	kfree(pathbuf);

	DBG(fsg, "transport=%s (x%02x)\n",
			mod_data.transport_name, mod_data.transport_type);
	DBG(fsg, "protocol=%s (x%02x)\n",
			mod_data.protocol_name, mod_data.protocol_type);
	DBG(fsg, "VendorID=x%04x, ProductID=x%04x, Release=x%04x\n",
			mod_data.vendor, mod_data.product, mod_data.release);
	DBG(fsg, "removable=%d, stall=%d, buflen=%u\n",
			mod_data.removable, mod_data.can_stall,
			mod_data.buflen);
	DBG(fsg, "I/O thread pid: %d\n", task_pid_nr(fsg->thread_task));

	set_bit(REGISTERED, &fsg->atomic_bitflags);

	/* Tell the thread to start working */
	wake_up_process(fsg->thread_task);
	return 0;

autoconf_fail:
	ERROR(fsg, "unable to autoconfigure all endpoints\n");
	rc = -ENOTSUPP;

out:
	fsg->state = FSG_STATE_TERMINATED;	// The thread is dead
	fsg_unbind(gadget);
	close_all_backing_files(fsg);
	return rc;
}


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

static void fsg_suspend(struct usb_gadget *gadget)
{
	struct fsg_dev		*fsg = get_gadget_data(gadget);

	DBG(fsg, "suspend\n");
	set_bit(SUSPENDED, &fsg->atomic_bitflags);
}

static void fsg_resume(struct usb_gadget *gadget)
{
	struct fsg_dev		*fsg = get_gadget_data(gadget);

	DBG(fsg, "resume\n");
	clear_bit(SUSPENDED, &fsg->atomic_bitflags);
}


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

static struct usb_gadget_driver		fsg_driver = {
#ifdef CONFIG_USB_GADGET_DUALSPEED
	.speed		= USB_SPEED_HIGH,
#else
	.speed		= USB_SPEED_FULL,
#endif
	.function	= (char *) longname,
	.bind		= fsg_bind,
	.unbind		= fsg_unbind,
	.disconnect	= fsg_disconnect,
	.setup		= fsg_setup,
	.suspend	= fsg_suspend,
	.resume		= fsg_resume,

	.driver		= {
		.name		= (char *) shortname,
		.owner		= THIS_MODULE,
		// .release = ...
		// .suspend = ...
		// .resume = ...
	},
};


static int __init fsg_alloc(void)
{
	struct fsg_dev		*fsg;

	fsg = kzalloc(sizeof *fsg, GFP_KERNEL);
	if (!fsg)
		return -ENOMEM;
	spin_lock_init(&fsg->lock);
	init_rwsem(&fsg->filesem);
	kref_init(&fsg->ref);
	init_completion(&fsg->thread_notifier);

	the_fsg = fsg;
	return 0;
}


static int __init fsg_init(void)
{
	int		rc;
	struct fsg_dev	*fsg;

	if ((rc = fsg_alloc()) != 0)
		return rc;
	fsg = the_fsg;
	if ((rc = usb_gadget_register_driver(&fsg_driver)) != 0)
		kref_put(&fsg->ref, fsg_release);
	return rc;
}
module_init(fsg_init);


static void __exit fsg_cleanup(void)
{
	struct fsg_dev	*fsg = the_fsg;

	/* Unregister the driver iff the thread hasn't already done so */
	if (test_and_clear_bit(REGISTERED, &fsg->atomic_bitflags))
		usb_gadget_unregister_driver(&fsg_driver);

	/* Wait for the thread to finish up */
	wait_for_completion(&fsg->thread_notifier);

	close_all_backing_files(fsg);
	kref_put(&fsg->ref, fsg_release);
}
module_exit(fsg_cleanup);