summaryrefslogtreecommitdiff
path: root/drivers/media/v4l2-core/videobuf2-core.c
blob: 594c75eab5a5d84b42d20ce6e5ba014fe91c0972 (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
/*
 * videobuf2-core.c - V4L2 driver helper framework
 *
 * Copyright (C) 2010 Samsung Electronics
 *
 * Author: Pawel Osciak <pawel@osciak.com>
 *	   Marek Szyprowski <m.szyprowski@samsung.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation.
 */

#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/sched.h>

#include <media/v4l2-dev.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-event.h>
#include <media/videobuf2-core.h>

static int debug;
module_param(debug, int, 0644);

#define dprintk(level, fmt, arg...)					\
	do {								\
		if (debug >= level)					\
			printk(KERN_DEBUG "vb2: " fmt, ## arg);		\
	} while (0)

#define call_memop(q, op, args...)					\
	(((q)->mem_ops->op) ?						\
		((q)->mem_ops->op(args)) : 0)

#define call_qop(q, op, args...)					\
	(((q)->ops->op) ? ((q)->ops->op(args)) : 0)

#define V4L2_BUFFER_MASK_FLAGS	(V4L2_BUF_FLAG_MAPPED | V4L2_BUF_FLAG_QUEUED | \
				 V4L2_BUF_FLAG_DONE | V4L2_BUF_FLAG_ERROR | \
				 V4L2_BUF_FLAG_PREPARED | \
				 V4L2_BUF_FLAG_TIMESTAMP_MASK)

/**
 * __vb2_buf_mem_alloc() - allocate video memory for the given buffer
 */
static int __vb2_buf_mem_alloc(struct vb2_buffer *vb)
{
	struct vb2_queue *q = vb->vb2_queue;
	void *mem_priv;
	int plane;

	/*
	 * Allocate memory for all planes in this buffer
	 * NOTE: mmapped areas should be page aligned
	 */
	for (plane = 0; plane < vb->num_planes; ++plane) {
		unsigned long size = PAGE_ALIGN(q->plane_sizes[plane]);

		mem_priv = call_memop(q, alloc, q->alloc_ctx[plane],
				      size, q->gfp_flags);
		if (IS_ERR_OR_NULL(mem_priv))
			goto free;

		/* Associate allocator private data with this plane */
		vb->planes[plane].mem_priv = mem_priv;
		vb->v4l2_planes[plane].length = q->plane_sizes[plane];
	}

	return 0;
free:
	/* Free already allocated memory if one of the allocations failed */
	for (; plane > 0; --plane) {
		call_memop(q, put, vb->planes[plane - 1].mem_priv);
		vb->planes[plane - 1].mem_priv = NULL;
	}

	return -ENOMEM;
}

/**
 * __vb2_buf_mem_free() - free memory of the given buffer
 */
static void __vb2_buf_mem_free(struct vb2_buffer *vb)
{
	struct vb2_queue *q = vb->vb2_queue;
	unsigned int plane;

	for (plane = 0; plane < vb->num_planes; ++plane) {
		call_memop(q, put, vb->planes[plane].mem_priv);
		vb->planes[plane].mem_priv = NULL;
		dprintk(3, "Freed plane %d of buffer %d\n", plane,
			vb->v4l2_buf.index);
	}
}

/**
 * __vb2_buf_userptr_put() - release userspace memory associated with
 * a USERPTR buffer
 */
static void __vb2_buf_userptr_put(struct vb2_buffer *vb)
{
	struct vb2_queue *q = vb->vb2_queue;
	unsigned int plane;

	for (plane = 0; plane < vb->num_planes; ++plane) {
		if (vb->planes[plane].mem_priv)
			call_memop(q, put_userptr, vb->planes[plane].mem_priv);
		vb->planes[plane].mem_priv = NULL;
	}
}

/**
 * __vb2_plane_dmabuf_put() - release memory associated with
 * a DMABUF shared plane
 */
static void __vb2_plane_dmabuf_put(struct vb2_queue *q, struct vb2_plane *p)
{
	if (!p->mem_priv)
		return;

	if (p->dbuf_mapped)
		call_memop(q, unmap_dmabuf, p->mem_priv);

	call_memop(q, detach_dmabuf, p->mem_priv);
	dma_buf_put(p->dbuf);
	memset(p, 0, sizeof(*p));
}

/**
 * __vb2_buf_dmabuf_put() - release memory associated with
 * a DMABUF shared buffer
 */
static void __vb2_buf_dmabuf_put(struct vb2_buffer *vb)
{
	struct vb2_queue *q = vb->vb2_queue;
	unsigned int plane;

	for (plane = 0; plane < vb->num_planes; ++plane)
		__vb2_plane_dmabuf_put(q, &vb->planes[plane]);
}

/**
 * __setup_offsets() - setup unique offsets ("cookies") for every plane in
 * every buffer on the queue
 */
static void __setup_offsets(struct vb2_queue *q, unsigned int n)
{
	unsigned int buffer, plane;
	struct vb2_buffer *vb;
	unsigned long off;

	if (q->num_buffers) {
		struct v4l2_plane *p;
		vb = q->bufs[q->num_buffers - 1];
		p = &vb->v4l2_planes[vb->num_planes - 1];
		off = PAGE_ALIGN(p->m.mem_offset + p->length);
	} else {
		off = 0;
	}

	for (buffer = q->num_buffers; buffer < q->num_buffers + n; ++buffer) {
		vb = q->bufs[buffer];
		if (!vb)
			continue;

		for (plane = 0; plane < vb->num_planes; ++plane) {
			vb->v4l2_planes[plane].length = q->plane_sizes[plane];
			vb->v4l2_planes[plane].m.mem_offset = off;

			dprintk(3, "Buffer %d, plane %d offset 0x%08lx\n",
					buffer, plane, off);

			off += vb->v4l2_planes[plane].length;
			off = PAGE_ALIGN(off);
		}
	}
}

/**
 * __vb2_queue_alloc() - allocate videobuf buffer structures and (for MMAP type)
 * video buffer memory for all buffers/planes on the queue and initializes the
 * queue
 *
 * Returns the number of buffers successfully allocated.
 */
static int __vb2_queue_alloc(struct vb2_queue *q, enum v4l2_memory memory,
			     unsigned int num_buffers, unsigned int num_planes)
{
	unsigned int buffer;
	struct vb2_buffer *vb;
	int ret;

	for (buffer = 0; buffer < num_buffers; ++buffer) {
		/* Allocate videobuf buffer structures */
		vb = kzalloc(q->buf_struct_size, GFP_KERNEL);
		if (!vb) {
			dprintk(1, "Memory alloc for buffer struct failed\n");
			break;
		}

		/* Length stores number of planes for multiplanar buffers */
		if (V4L2_TYPE_IS_MULTIPLANAR(q->type))
			vb->v4l2_buf.length = num_planes;

		vb->state = VB2_BUF_STATE_DEQUEUED;
		vb->vb2_queue = q;
		vb->num_planes = num_planes;
		vb->v4l2_buf.index = q->num_buffers + buffer;
		vb->v4l2_buf.type = q->type;
		vb->v4l2_buf.memory = memory;

		/* Allocate video buffer memory for the MMAP type */
		if (memory == V4L2_MEMORY_MMAP) {
			ret = __vb2_buf_mem_alloc(vb);
			if (ret) {
				dprintk(1, "Failed allocating memory for "
						"buffer %d\n", buffer);
				kfree(vb);
				break;
			}
			/*
			 * Call the driver-provided buffer initialization
			 * callback, if given. An error in initialization
			 * results in queue setup failure.
			 */
			ret = call_qop(q, buf_init, vb);
			if (ret) {
				dprintk(1, "Buffer %d %p initialization"
					" failed\n", buffer, vb);
				__vb2_buf_mem_free(vb);
				kfree(vb);
				break;
			}
		}

		q->bufs[q->num_buffers + buffer] = vb;
	}

	__setup_offsets(q, buffer);

	dprintk(1, "Allocated %d buffers, %d plane(s) each\n",
			buffer, num_planes);

	return buffer;
}

/**
 * __vb2_free_mem() - release all video buffer memory for a given queue
 */
static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers)
{
	unsigned int buffer;
	struct vb2_buffer *vb;

	for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
	     ++buffer) {
		vb = q->bufs[buffer];
		if (!vb)
			continue;

		/* Free MMAP buffers or release USERPTR buffers */
		if (q->memory == V4L2_MEMORY_MMAP)
			__vb2_buf_mem_free(vb);
		else if (q->memory == V4L2_MEMORY_DMABUF)
			__vb2_buf_dmabuf_put(vb);
		else
			__vb2_buf_userptr_put(vb);
	}
}

/**
 * __vb2_queue_free() - free buffers at the end of the queue - video memory and
 * related information, if no buffers are left return the queue to an
 * uninitialized state. Might be called even if the queue has already been freed.
 */
static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
{
	unsigned int buffer;

	/* Call driver-provided cleanup function for each buffer, if provided */
	if (q->ops->buf_cleanup) {
		for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
		     ++buffer) {
			if (NULL == q->bufs[buffer])
				continue;
			q->ops->buf_cleanup(q->bufs[buffer]);
		}
	}

	/* Release video buffer memory */
	__vb2_free_mem(q, buffers);

	/* Free videobuf buffers */
	for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
	     ++buffer) {
		kfree(q->bufs[buffer]);
		q->bufs[buffer] = NULL;
	}

	q->num_buffers -= buffers;
	if (!q->num_buffers)
		q->memory = 0;
	INIT_LIST_HEAD(&q->queued_list);
}

/**
 * __verify_planes_array() - verify that the planes array passed in struct
 * v4l2_buffer from userspace can be safely used
 */
static int __verify_planes_array(struct vb2_buffer *vb, const struct v4l2_buffer *b)
{
	if (!V4L2_TYPE_IS_MULTIPLANAR(b->type))
		return 0;

	/* Is memory for copying plane information present? */
	if (NULL == b->m.planes) {
		dprintk(1, "Multi-planar buffer passed but "
			   "planes array not provided\n");
		return -EINVAL;
	}

	if (b->length < vb->num_planes || b->length > VIDEO_MAX_PLANES) {
		dprintk(1, "Incorrect planes array length, "
			   "expected %d, got %d\n", vb->num_planes, b->length);
		return -EINVAL;
	}

	return 0;
}

/**
 * __verify_length() - Verify that the bytesused value for each plane fits in
 * the plane length and that the data offset doesn't exceed the bytesused value.
 */
static int __verify_length(struct vb2_buffer *vb, const struct v4l2_buffer *b)
{
	unsigned int length;
	unsigned int plane;

	if (!V4L2_TYPE_IS_OUTPUT(b->type))
		return 0;

	if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) {
		for (plane = 0; plane < vb->num_planes; ++plane) {
			length = (b->memory == V4L2_MEMORY_USERPTR)
			       ? b->m.planes[plane].length
			       : vb->v4l2_planes[plane].length;

			if (b->m.planes[plane].bytesused > length)
				return -EINVAL;
			if (b->m.planes[plane].data_offset >=
			    b->m.planes[plane].bytesused)
				return -EINVAL;
		}
	} else {
		length = (b->memory == V4L2_MEMORY_USERPTR)
		       ? b->length : vb->v4l2_planes[0].length;

		if (b->bytesused > length)
			return -EINVAL;
	}

	return 0;
}

/**
 * __buffer_in_use() - return true if the buffer is in use and
 * the queue cannot be freed (by the means of REQBUFS(0)) call
 */
static bool __buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb)
{
	unsigned int plane;
	for (plane = 0; plane < vb->num_planes; ++plane) {
		void *mem_priv = vb->planes[plane].mem_priv;
		/*
		 * If num_users() has not been provided, call_memop
		 * will return 0, apparently nobody cares about this
		 * case anyway. If num_users() returns more than 1,
		 * we are not the only user of the plane's memory.
		 */
		if (mem_priv && call_memop(q, num_users, mem_priv) > 1)
			return true;
	}
	return false;
}

/**
 * __buffers_in_use() - return true if any buffers on the queue are in use and
 * the queue cannot be freed (by the means of REQBUFS(0)) call
 */
static bool __buffers_in_use(struct vb2_queue *q)
{
	unsigned int buffer;
	for (buffer = 0; buffer < q->num_buffers; ++buffer) {
		if (__buffer_in_use(q, q->bufs[buffer]))
			return true;
	}
	return false;
}

/**
 * __fill_v4l2_buffer() - fill in a struct v4l2_buffer with information to be
 * returned to userspace
 */
static void __fill_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b)
{
	struct vb2_queue *q = vb->vb2_queue;

	/* Copy back data such as timestamp, flags, etc. */
	memcpy(b, &vb->v4l2_buf, offsetof(struct v4l2_buffer, m));
	b->reserved2 = vb->v4l2_buf.reserved2;
	b->reserved = vb->v4l2_buf.reserved;

	if (V4L2_TYPE_IS_MULTIPLANAR(q->type)) {
		/*
		 * Fill in plane-related data if userspace provided an array
		 * for it. The caller has already verified memory and size.
		 */
		b->length = vb->num_planes;
		memcpy(b->m.planes, vb->v4l2_planes,
			b->length * sizeof(struct v4l2_plane));
	} else {
		/*
		 * We use length and offset in v4l2_planes array even for
		 * single-planar buffers, but userspace does not.
		 */
		b->length = vb->v4l2_planes[0].length;
		b->bytesused = vb->v4l2_planes[0].bytesused;
		if (q->memory == V4L2_MEMORY_MMAP)
			b->m.offset = vb->v4l2_planes[0].m.mem_offset;
		else if (q->memory == V4L2_MEMORY_USERPTR)
			b->m.userptr = vb->v4l2_planes[0].m.userptr;
		else if (q->memory == V4L2_MEMORY_DMABUF)
			b->m.fd = vb->v4l2_planes[0].m.fd;
	}

	/*
	 * Clear any buffer state related flags.
	 */
	b->flags &= ~V4L2_BUFFER_MASK_FLAGS;
	b->flags |= q->timestamp_type;

	switch (vb->state) {
	case VB2_BUF_STATE_QUEUED:
	case VB2_BUF_STATE_ACTIVE:
		b->flags |= V4L2_BUF_FLAG_QUEUED;
		break;
	case VB2_BUF_STATE_ERROR:
		b->flags |= V4L2_BUF_FLAG_ERROR;
		/* fall through */
	case VB2_BUF_STATE_DONE:
		b->flags |= V4L2_BUF_FLAG_DONE;
		break;
	case VB2_BUF_STATE_PREPARED:
		b->flags |= V4L2_BUF_FLAG_PREPARED;
		break;
	case VB2_BUF_STATE_DEQUEUED:
		/* nothing */
		break;
	}

	if (__buffer_in_use(q, vb))
		b->flags |= V4L2_BUF_FLAG_MAPPED;
}

/**
 * vb2_querybuf() - query video buffer information
 * @q:		videobuf queue
 * @b:		buffer struct passed from userspace to vidioc_querybuf handler
 *		in driver
 *
 * Should be called from vidioc_querybuf ioctl handler in driver.
 * This function will verify the passed v4l2_buffer structure and fill the
 * relevant information for the userspace.
 *
 * The return values from this function are intended to be directly returned
 * from vidioc_querybuf handler in driver.
 */
int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b)
{
	struct vb2_buffer *vb;
	int ret;

	if (b->type != q->type) {
		dprintk(1, "querybuf: wrong buffer type\n");
		return -EINVAL;
	}

	if (b->index >= q->num_buffers) {
		dprintk(1, "querybuf: buffer index out of range\n");
		return -EINVAL;
	}
	vb = q->bufs[b->index];
	ret = __verify_planes_array(vb, b);
	if (!ret)
		__fill_v4l2_buffer(vb, b);
	return ret;
}
EXPORT_SYMBOL(vb2_querybuf);

/**
 * __verify_userptr_ops() - verify that all memory operations required for
 * USERPTR queue type have been provided
 */
static int __verify_userptr_ops(struct vb2_queue *q)
{
	if (!(q->io_modes & VB2_USERPTR) || !q->mem_ops->get_userptr ||
	    !q->mem_ops->put_userptr)
		return -EINVAL;

	return 0;
}

/**
 * __verify_mmap_ops() - verify that all memory operations required for
 * MMAP queue type have been provided
 */
static int __verify_mmap_ops(struct vb2_queue *q)
{
	if (!(q->io_modes & VB2_MMAP) || !q->mem_ops->alloc ||
	    !q->mem_ops->put || !q->mem_ops->mmap)
		return -EINVAL;

	return 0;
}

/**
 * __verify_dmabuf_ops() - verify that all memory operations required for
 * DMABUF queue type have been provided
 */
static int __verify_dmabuf_ops(struct vb2_queue *q)
{
	if (!(q->io_modes & VB2_DMABUF) || !q->mem_ops->attach_dmabuf ||
	    !q->mem_ops->detach_dmabuf  || !q->mem_ops->map_dmabuf ||
	    !q->mem_ops->unmap_dmabuf)
		return -EINVAL;

	return 0;
}

/**
 * __verify_memory_type() - Check whether the memory type and buffer type
 * passed to a buffer operation are compatible with the queue.
 */
static int __verify_memory_type(struct vb2_queue *q,
		enum v4l2_memory memory, enum v4l2_buf_type type)
{
	if (memory != V4L2_MEMORY_MMAP && memory != V4L2_MEMORY_USERPTR &&
	    memory != V4L2_MEMORY_DMABUF) {
		dprintk(1, "reqbufs: unsupported memory type\n");
		return -EINVAL;
	}

	if (type != q->type) {
		dprintk(1, "reqbufs: requested type is incorrect\n");
		return -EINVAL;
	}

	/*
	 * Make sure all the required memory ops for given memory type
	 * are available.
	 */
	if (memory == V4L2_MEMORY_MMAP && __verify_mmap_ops(q)) {
		dprintk(1, "reqbufs: MMAP for current setup unsupported\n");
		return -EINVAL;
	}

	if (memory == V4L2_MEMORY_USERPTR && __verify_userptr_ops(q)) {
		dprintk(1, "reqbufs: USERPTR for current setup unsupported\n");
		return -EINVAL;
	}

	if (memory == V4L2_MEMORY_DMABUF && __verify_dmabuf_ops(q)) {
		dprintk(1, "reqbufs: DMABUF for current setup unsupported\n");
		return -EINVAL;
	}

	/*
	 * Place the busy tests at the end: -EBUSY can be ignored when
	 * create_bufs is called with count == 0, but count == 0 should still
	 * do the memory and type validation.
	 */
	if (q->fileio) {
		dprintk(1, "reqbufs: file io in progress\n");
		return -EBUSY;
	}
	return 0;
}

/**
 * __reqbufs() - Initiate streaming
 * @q:		videobuf2 queue
 * @req:	struct passed from userspace to vidioc_reqbufs handler in driver
 *
 * Should be called from vidioc_reqbufs ioctl handler of a driver.
 * This function:
 * 1) verifies streaming parameters passed from the userspace,
 * 2) sets up the queue,
 * 3) negotiates number of buffers and planes per buffer with the driver
 *    to be used during streaming,
 * 4) allocates internal buffer structures (struct vb2_buffer), according to
 *    the agreed parameters,
 * 5) for MMAP memory type, allocates actual video memory, using the
 *    memory handling/allocation routines provided during queue initialization
 *
 * If req->count is 0, all the memory will be freed instead.
 * If the queue has been allocated previously (by a previous vb2_reqbufs) call
 * and the queue is not busy, memory will be reallocated.
 *
 * The return values from this function are intended to be directly returned
 * from vidioc_reqbufs handler in driver.
 */
static int __reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
{
	unsigned int num_buffers, allocated_buffers, num_planes = 0;
	int ret;

	if (q->streaming) {
		dprintk(1, "reqbufs: streaming active\n");
		return -EBUSY;
	}

	if (req->count == 0 || q->num_buffers != 0 || q->memory != req->memory) {
		/*
		 * We already have buffers allocated, so first check if they
		 * are not in use and can be freed.
		 */
		if (q->memory == V4L2_MEMORY_MMAP && __buffers_in_use(q)) {
			dprintk(1, "reqbufs: memory in use, cannot free\n");
			return -EBUSY;
		}

		__vb2_queue_free(q, q->num_buffers);

		/*
		 * In case of REQBUFS(0) return immediately without calling
		 * driver's queue_setup() callback and allocating resources.
		 */
		if (req->count == 0)
			return 0;
	}

	/*
	 * Make sure the requested values and current defaults are sane.
	 */
	num_buffers = min_t(unsigned int, req->count, VIDEO_MAX_FRAME);
	memset(q->plane_sizes, 0, sizeof(q->plane_sizes));
	memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
	q->memory = req->memory;

	/*
	 * Ask the driver how many buffers and planes per buffer it requires.
	 * Driver also sets the size and allocator context for each plane.
	 */
	ret = call_qop(q, queue_setup, q, NULL, &num_buffers, &num_planes,
		       q->plane_sizes, q->alloc_ctx);
	if (ret)
		return ret;

	/* Finally, allocate buffers and video memory */
	ret = __vb2_queue_alloc(q, req->memory, num_buffers, num_planes);
	if (ret == 0) {
		dprintk(1, "Memory allocation failed\n");
		return -ENOMEM;
	}

	allocated_buffers = ret;

	/*
	 * Check if driver can handle the allocated number of buffers.
	 */
	if (allocated_buffers < num_buffers) {
		num_buffers = allocated_buffers;

		ret = call_qop(q, queue_setup, q, NULL, &num_buffers,
			       &num_planes, q->plane_sizes, q->alloc_ctx);

		if (!ret && allocated_buffers < num_buffers)
			ret = -ENOMEM;

		/*
		 * Either the driver has accepted a smaller number of buffers,
		 * or .queue_setup() returned an error
		 */
	}

	q->num_buffers = allocated_buffers;

	if (ret < 0) {
		__vb2_queue_free(q, allocated_buffers);
		return ret;
	}

	/*
	 * Return the number of successfully allocated buffers
	 * to the userspace.
	 */
	req->count = allocated_buffers;

	return 0;
}

/**
 * vb2_reqbufs() - Wrapper for __reqbufs() that also verifies the memory and
 * type values.
 * @q:		videobuf2 queue
 * @req:	struct passed from userspace to vidioc_reqbufs handler in driver
 */
int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
{
	int ret = __verify_memory_type(q, req->memory, req->type);

	return ret ? ret : __reqbufs(q, req);
}
EXPORT_SYMBOL_GPL(vb2_reqbufs);

/**
 * __create_bufs() - Allocate buffers and any required auxiliary structs
 * @q:		videobuf2 queue
 * @create:	creation parameters, passed from userspace to vidioc_create_bufs
 *		handler in driver
 *
 * Should be called from vidioc_create_bufs ioctl handler of a driver.
 * This function:
 * 1) verifies parameter sanity
 * 2) calls the .queue_setup() queue operation
 * 3) performs any necessary memory allocations
 *
 * The return values from this function are intended to be directly returned
 * from vidioc_create_bufs handler in driver.
 */
static int __create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
{
	unsigned int num_planes = 0, num_buffers, allocated_buffers;
	int ret;

	if (q->num_buffers == VIDEO_MAX_FRAME) {
		dprintk(1, "%s(): maximum number of buffers already allocated\n",
			__func__);
		return -ENOBUFS;
	}

	if (!q->num_buffers) {
		memset(q->plane_sizes, 0, sizeof(q->plane_sizes));
		memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
		q->memory = create->memory;
	}

	num_buffers = min(create->count, VIDEO_MAX_FRAME - q->num_buffers);

	/*
	 * Ask the driver, whether the requested number of buffers, planes per
	 * buffer and their sizes are acceptable
	 */
	ret = call_qop(q, queue_setup, q, &create->format, &num_buffers,
		       &num_planes, q->plane_sizes, q->alloc_ctx);
	if (ret)
		return ret;

	/* Finally, allocate buffers and video memory */
	ret = __vb2_queue_alloc(q, create->memory, num_buffers,
				num_planes);
	if (ret == 0) {
		dprintk(1, "Memory allocation failed\n");
		return -ENOMEM;
	}

	allocated_buffers = ret;

	/*
	 * Check if driver can handle the so far allocated number of buffers.
	 */
	if (ret < num_buffers) {
		num_buffers = ret;

		/*
		 * q->num_buffers contains the total number of buffers, that the
		 * queue driver has set up
		 */
		ret = call_qop(q, queue_setup, q, &create->format, &num_buffers,
			       &num_planes, q->plane_sizes, q->alloc_ctx);

		if (!ret && allocated_buffers < num_buffers)
			ret = -ENOMEM;

		/*
		 * Either the driver has accepted a smaller number of buffers,
		 * or .queue_setup() returned an error
		 */
	}

	q->num_buffers += allocated_buffers;

	if (ret < 0) {
		__vb2_queue_free(q, allocated_buffers);
		return -ENOMEM;
	}

	/*
	 * Return the number of successfully allocated buffers
	 * to the userspace.
	 */
	create->count = allocated_buffers;

	return 0;
}

/**
 * vb2_create_bufs() - Wrapper for __create_bufs() that also verifies the
 * memory and type values.
 * @q:		videobuf2 queue
 * @create:	creation parameters, passed from userspace to vidioc_create_bufs
 *		handler in driver
 */
int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
{
	int ret = __verify_memory_type(q, create->memory, create->format.type);

	create->index = q->num_buffers;
	if (create->count == 0)
		return ret != -EBUSY ? ret : 0;
	return ret ? ret : __create_bufs(q, create);
}
EXPORT_SYMBOL_GPL(vb2_create_bufs);

/**
 * vb2_plane_vaddr() - Return a kernel virtual address of a given plane
 * @vb:		vb2_buffer to which the plane in question belongs to
 * @plane_no:	plane number for which the address is to be returned
 *
 * This function returns a kernel virtual address of a given plane if
 * such a mapping exist, NULL otherwise.
 */
void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no)
{
	struct vb2_queue *q = vb->vb2_queue;

	if (plane_no > vb->num_planes || !vb->planes[plane_no].mem_priv)
		return NULL;

	return call_memop(q, vaddr, vb->planes[plane_no].mem_priv);

}
EXPORT_SYMBOL_GPL(vb2_plane_vaddr);

/**
 * vb2_plane_cookie() - Return allocator specific cookie for the given plane
 * @vb:		vb2_buffer to which the plane in question belongs to
 * @plane_no:	plane number for which the cookie is to be returned
 *
 * This function returns an allocator specific cookie for a given plane if
 * available, NULL otherwise. The allocator should provide some simple static
 * inline function, which would convert this cookie to the allocator specific
 * type that can be used directly by the driver to access the buffer. This can
 * be for example physical address, pointer to scatter list or IOMMU mapping.
 */
void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no)
{
	struct vb2_queue *q = vb->vb2_queue;

	if (plane_no > vb->num_planes || !vb->planes[plane_no].mem_priv)
		return NULL;

	return call_memop(q, cookie, vb->planes[plane_no].mem_priv);
}
EXPORT_SYMBOL_GPL(vb2_plane_cookie);

/**
 * vb2_buffer_done() - inform videobuf that an operation on a buffer is finished
 * @vb:		vb2_buffer returned from the driver
 * @state:	either VB2_BUF_STATE_DONE if the operation finished successfully
 *		or VB2_BUF_STATE_ERROR if the operation finished with an error
 *
 * This function should be called by the driver after a hardware operation on
 * a buffer is finished and the buffer may be returned to userspace. The driver
 * cannot use this buffer anymore until it is queued back to it by videobuf
 * by the means of buf_queue callback. Only buffers previously queued to the
 * driver by buf_queue can be passed to this function.
 */
void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
{
	struct vb2_queue *q = vb->vb2_queue;
	unsigned long flags;
	unsigned int plane;

	if (vb->state != VB2_BUF_STATE_ACTIVE)
		return;

	if (state != VB2_BUF_STATE_DONE && state != VB2_BUF_STATE_ERROR)
		return;

	dprintk(4, "Done processing on buffer %d, state: %d\n",
			vb->v4l2_buf.index, state);

	/* sync buffers */
	for (plane = 0; plane < vb->num_planes; ++plane)
		call_memop(q, finish, vb->planes[plane].mem_priv);

	/* Add the buffer to the done buffers list */
	spin_lock_irqsave(&q->done_lock, flags);
	vb->state = state;
	list_add_tail(&vb->done_entry, &q->done_list);
	atomic_dec(&q->queued_count);
	spin_unlock_irqrestore(&q->done_lock, flags);

	/* Inform any processes that may be waiting for buffers */
	wake_up(&q->done_wq);
}
EXPORT_SYMBOL_GPL(vb2_buffer_done);

/**
 * __fill_vb2_buffer() - fill a vb2_buffer with information provided in a
 * v4l2_buffer by the userspace. The caller has already verified that struct
 * v4l2_buffer has a valid number of planes.
 */
static void __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b,
				struct v4l2_plane *v4l2_planes)
{
	unsigned int plane;

	if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) {
		/* Fill in driver-provided information for OUTPUT types */
		if (V4L2_TYPE_IS_OUTPUT(b->type)) {
			/*
			 * Will have to go up to b->length when API starts
			 * accepting variable number of planes.
			 */
			for (plane = 0; plane < vb->num_planes; ++plane) {
				v4l2_planes[plane].bytesused =
					b->m.planes[plane].bytesused;
				v4l2_planes[plane].data_offset =
					b->m.planes[plane].data_offset;
			}
		}

		if (b->memory == V4L2_MEMORY_USERPTR) {
			for (plane = 0; plane < vb->num_planes; ++plane) {
				v4l2_planes[plane].m.userptr =
					b->m.planes[plane].m.userptr;
				v4l2_planes[plane].length =
					b->m.planes[plane].length;
			}
		}
		if (b->memory == V4L2_MEMORY_DMABUF) {
			for (plane = 0; plane < vb->num_planes; ++plane) {
				v4l2_planes[plane].m.fd =
					b->m.planes[plane].m.fd;
				v4l2_planes[plane].length =
					b->m.planes[plane].length;
				v4l2_planes[plane].data_offset =
					b->m.planes[plane].data_offset;
			}
		}
	} else {
		/*
		 * Single-planar buffers do not use planes array,
		 * so fill in relevant v4l2_buffer struct fields instead.
		 * In videobuf we use our internal V4l2_planes struct for
		 * single-planar buffers as well, for simplicity.
		 */
		if (V4L2_TYPE_IS_OUTPUT(b->type)) {
			v4l2_planes[0].bytesused = b->bytesused;
			v4l2_planes[0].data_offset = 0;
		}

		if (b->memory == V4L2_MEMORY_USERPTR) {
			v4l2_planes[0].m.userptr = b->m.userptr;
			v4l2_planes[0].length = b->length;
		}

		if (b->memory == V4L2_MEMORY_DMABUF) {
			v4l2_planes[0].m.fd = b->m.fd;
			v4l2_planes[0].length = b->length;
			v4l2_planes[0].data_offset = 0;
		}

	}

	vb->v4l2_buf.field = b->field;
	vb->v4l2_buf.timestamp = b->timestamp;
	vb->v4l2_buf.flags = b->flags & ~V4L2_BUFFER_MASK_FLAGS;
}

/**
 * __qbuf_userptr() - handle qbuf of a USERPTR buffer
 */
static int __qbuf_userptr(struct vb2_buffer *vb, const struct v4l2_buffer *b)
{
	struct v4l2_plane planes[VIDEO_MAX_PLANES];
	struct vb2_queue *q = vb->vb2_queue;
	void *mem_priv;
	unsigned int plane;
	int ret;
	int write = !V4L2_TYPE_IS_OUTPUT(q->type);

	/* Copy relevant information provided by the userspace */
	__fill_vb2_buffer(vb, b, planes);

	for (plane = 0; plane < vb->num_planes; ++plane) {
		/* Skip the plane if already verified */
		if (vb->v4l2_planes[plane].m.userptr &&
		    vb->v4l2_planes[plane].m.userptr == planes[plane].m.userptr
		    && vb->v4l2_planes[plane].length == planes[plane].length)
			continue;

		dprintk(3, "qbuf: userspace address for plane %d changed, "
				"reacquiring memory\n", plane);

		/* Check if the provided plane buffer is large enough */
		if (planes[plane].length < q->plane_sizes[plane]) {
			ret = -EINVAL;
			goto err;
		}

		/* Release previously acquired memory if present */
		if (vb->planes[plane].mem_priv)
			call_memop(q, put_userptr, vb->planes[plane].mem_priv);

		vb->planes[plane].mem_priv = NULL;
		vb->v4l2_planes[plane].m.userptr = 0;
		vb->v4l2_planes[plane].length = 0;

		/* Acquire each plane's memory */
		mem_priv = call_memop(q, get_userptr, q->alloc_ctx[plane],
				      planes[plane].m.userptr,
				      planes[plane].length, write);
		if (IS_ERR_OR_NULL(mem_priv)) {
			dprintk(1, "qbuf: failed acquiring userspace "
						"memory for plane %d\n", plane);
			ret = mem_priv ? PTR_ERR(mem_priv) : -EINVAL;
			goto err;
		}
		vb->planes[plane].mem_priv = mem_priv;
	}

	/*
	 * Call driver-specific initialization on the newly acquired buffer,
	 * if provided.
	 */
	ret = call_qop(q, buf_init, vb);
	if (ret) {
		dprintk(1, "qbuf: buffer initialization failed\n");
		goto err;
	}

	/*
	 * Now that everything is in order, copy relevant information
	 * provided by userspace.
	 */
	for (plane = 0; plane < vb->num_planes; ++plane)
		vb->v4l2_planes[plane] = planes[plane];

	return 0;
err:
	/* In case of errors, release planes that were already acquired */
	for (plane = 0; plane < vb->num_planes; ++plane) {
		if (vb->planes[plane].mem_priv)
			call_memop(q, put_userptr, vb->planes[plane].mem_priv);
		vb->planes[plane].mem_priv = NULL;
		vb->v4l2_planes[plane].m.userptr = 0;
		vb->v4l2_planes[plane].length = 0;
	}

	return ret;
}

/**
 * __qbuf_mmap() - handle qbuf of an MMAP buffer
 */
static int __qbuf_mmap(struct vb2_buffer *vb, const struct v4l2_buffer *b)
{
	__fill_vb2_buffer(vb, b, vb->v4l2_planes);
	return 0;
}

/**
 * __qbuf_dmabuf() - handle qbuf of a DMABUF buffer
 */
static int __qbuf_dmabuf(struct vb2_buffer *vb, const struct v4l2_buffer *b)
{
	struct v4l2_plane planes[VIDEO_MAX_PLANES];
	struct vb2_queue *q = vb->vb2_queue;
	void *mem_priv;
	unsigned int plane;
	int ret;
	int write = !V4L2_TYPE_IS_OUTPUT(q->type);

	/* Verify and copy relevant information provided by the userspace */
	__fill_vb2_buffer(vb, b, planes);

	for (plane = 0; plane < vb->num_planes; ++plane) {
		struct dma_buf *dbuf = dma_buf_get(planes[plane].m.fd);

		if (IS_ERR_OR_NULL(dbuf)) {
			dprintk(1, "qbuf: invalid dmabuf fd for plane %d\n",
				plane);
			ret = -EINVAL;
			goto err;
		}

		/* use DMABUF size if length is not provided */
		if (planes[plane].length == 0)
			planes[plane].length = dbuf->size;

		if (planes[plane].length < planes[plane].data_offset +
		    q->plane_sizes[plane]) {
			ret = -EINVAL;
			goto err;
		}

		/* Skip the plane if already verified */
		if (dbuf == vb->planes[plane].dbuf &&
		    vb->v4l2_planes[plane].length == planes[plane].length) {
			dma_buf_put(dbuf);
			continue;
		}

		dprintk(1, "qbuf: buffer for plane %d changed\n", plane);

		/* Release previously acquired memory if present */
		__vb2_plane_dmabuf_put(q, &vb->planes[plane]);
		memset(&vb->v4l2_planes[plane], 0, sizeof(struct v4l2_plane));

		/* Acquire each plane's memory */
		mem_priv = call_memop(q, attach_dmabuf, q->alloc_ctx[plane],
			dbuf, planes[plane].length, write);
		if (IS_ERR(mem_priv)) {
			dprintk(1, "qbuf: failed to attach dmabuf\n");
			ret = PTR_ERR(mem_priv);
			dma_buf_put(dbuf);
			goto err;
		}

		vb->planes[plane].dbuf = dbuf;
		vb->planes[plane].mem_priv = mem_priv;
	}

	/* TODO: This pins the buffer(s) with  dma_buf_map_attachment()).. but
	 * really we want to do this just before the DMA, not while queueing
	 * the buffer(s)..
	 */
	for (plane = 0; plane < vb->num_planes; ++plane) {
		ret = call_memop(q, map_dmabuf, vb->planes[plane].mem_priv);
		if (ret) {
			dprintk(1, "qbuf: failed to map dmabuf for plane %d\n",
				plane);
			goto err;
		}
		vb->planes[plane].dbuf_mapped = 1;
	}

	/*
	 * Call driver-specific initialization on the newly acquired buffer,
	 * if provided.
	 */
	ret = call_qop(q, buf_init, vb);
	if (ret) {
		dprintk(1, "qbuf: buffer initialization failed\n");
		goto err;
	}

	/*
	 * Now that everything is in order, copy relevant information
	 * provided by userspace.
	 */
	for (plane = 0; plane < vb->num_planes; ++plane)
		vb->v4l2_planes[plane] = planes[plane];

	return 0;
err:
	/* In case of errors, release planes that were already acquired */
	__vb2_buf_dmabuf_put(vb);

	return ret;
}

/**
 * __enqueue_in_driver() - enqueue a vb2_buffer in driver for processing
 */
static void __enqueue_in_driver(struct vb2_buffer *vb)
{
	struct vb2_queue *q = vb->vb2_queue;
	unsigned int plane;

	vb->state = VB2_BUF_STATE_ACTIVE;
	atomic_inc(&q->queued_count);

	/* sync buffers */
	for (plane = 0; plane < vb->num_planes; ++plane)
		call_memop(q, prepare, vb->planes[plane].mem_priv);

	q->ops->buf_queue(vb);
}

static int __buf_prepare(struct vb2_buffer *vb, const struct v4l2_buffer *b)
{
	struct vb2_queue *q = vb->vb2_queue;
	int ret;

	ret = __verify_length(vb, b);
	if (ret < 0)
		return ret;

	switch (q->memory) {
	case V4L2_MEMORY_MMAP:
		ret = __qbuf_mmap(vb, b);
		break;
	case V4L2_MEMORY_USERPTR:
		ret = __qbuf_userptr(vb, b);
		break;
	case V4L2_MEMORY_DMABUF:
		ret = __qbuf_dmabuf(vb, b);
		break;
	default:
		WARN(1, "Invalid queue type\n");
		ret = -EINVAL;
	}

	if (!ret)
		ret = call_qop(q, buf_prepare, vb);
	if (ret)
		dprintk(1, "qbuf: buffer preparation failed: %d\n", ret);
	else
		vb->state = VB2_BUF_STATE_PREPARED;

	return ret;
}

static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b,
				    const char *opname,
				    int (*handler)(struct vb2_queue *,
						   struct v4l2_buffer *,
						   struct vb2_buffer *))
{
	struct rw_semaphore *mmap_sem = NULL;
	struct vb2_buffer *vb;
	int ret;

	/*
	 * In case of user pointer buffers vb2 allocators need to get direct
	 * access to userspace pages. This requires getting the mmap semaphore
	 * for read access in the current process structure. The same semaphore
	 * is taken before calling mmap operation, while both qbuf/prepare_buf
	 * and mmap are called by the driver or v4l2 core with the driver's lock
	 * held. To avoid an AB-BA deadlock (mmap_sem then driver's lock in mmap
	 * and driver's lock then mmap_sem in qbuf/prepare_buf) the videobuf2
	 * core releases the driver's lock, takes mmap_sem and then takes the
	 * driver's lock again.
	 *
	 * To avoid racing with other vb2 calls, which might be called after
	 * releasing the driver's lock, this operation is performed at the
	 * beginning of qbuf/prepare_buf processing. This way the queue status
	 * is consistent after getting the driver's lock back.
	 */
	if (q->memory == V4L2_MEMORY_USERPTR) {
		mmap_sem = &current->mm->mmap_sem;
		call_qop(q, wait_prepare, q);
		down_read(mmap_sem);
		call_qop(q, wait_finish, q);
	}

	if (q->fileio) {
		dprintk(1, "%s(): file io in progress\n", opname);
		ret = -EBUSY;
		goto unlock;
	}

	if (b->type != q->type) {
		dprintk(1, "%s(): invalid buffer type\n", opname);
		ret = -EINVAL;
		goto unlock;
	}

	if (b->index >= q->num_buffers) {
		dprintk(1, "%s(): buffer index out of range\n", opname);
		ret = -EINVAL;
		goto unlock;
	}

	vb = q->bufs[b->index];
	if (NULL == vb) {
		/* Should never happen */
		dprintk(1, "%s(): buffer is NULL\n", opname);
		ret = -EINVAL;
		goto unlock;
	}

	if (b->memory != q->memory) {
		dprintk(1, "%s(): invalid memory type\n", opname);
		ret = -EINVAL;
		goto unlock;
	}

	ret = __verify_planes_array(vb, b);
	if (ret)
		goto unlock;

	ret = handler(q, b, vb);
	if (ret)
		goto unlock;

	/* Fill buffer information for the userspace */
	__fill_v4l2_buffer(vb, b);

	dprintk(1, "%s() of buffer %d succeeded\n", opname, vb->v4l2_buf.index);
unlock:
	if (mmap_sem)
		up_read(mmap_sem);
	return ret;
}

static int __vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b,
			     struct vb2_buffer *vb)
{
	if (vb->state != VB2_BUF_STATE_DEQUEUED) {
		dprintk(1, "%s(): invalid buffer state %d\n", __func__,
			vb->state);
		return -EINVAL;
	}

	return __buf_prepare(vb, b);
}

/**
 * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel
 * @q:		videobuf2 queue
 * @b:		buffer structure passed from userspace to vidioc_prepare_buf
 *		handler in driver
 *
 * Should be called from vidioc_prepare_buf ioctl handler of a driver.
 * This function:
 * 1) verifies the passed buffer,
 * 2) calls buf_prepare callback in the driver (if provided), in which
 *    driver-specific buffer initialization can be performed,
 *
 * The return values from this function are intended to be directly returned
 * from vidioc_prepare_buf handler in driver.
 */
int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b)
{
	return vb2_queue_or_prepare_buf(q, b, "prepare_buf", __vb2_prepare_buf);
}
EXPORT_SYMBOL_GPL(vb2_prepare_buf);

static int __vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b,
		      struct vb2_buffer *vb)
{
	int ret;

	switch (vb->state) {
	case VB2_BUF_STATE_DEQUEUED:
		ret = __buf_prepare(vb, b);
		if (ret)
			return ret;
	case VB2_BUF_STATE_PREPARED:
		break;
	default:
		dprintk(1, "qbuf: buffer already in use\n");
		return -EINVAL;
	}

	/*
	 * Add to the queued buffers list, a buffer will stay on it until
	 * dequeued in dqbuf.
	 */
	list_add_tail(&vb->queued_entry, &q->queued_list);
	vb->state = VB2_BUF_STATE_QUEUED;

	/*
	 * If already streaming, give the buffer to driver for processing.
	 * If not, the buffer will be given to driver on next streamon.
	 */
	if (q->streaming)
		__enqueue_in_driver(vb);

	return 0;
}

/**
 * vb2_qbuf() - Queue a buffer from userspace
 * @q:		videobuf2 queue
 * @b:		buffer structure passed from userspace to vidioc_qbuf handler
 *		in driver
 *
 * Should be called from vidioc_qbuf ioctl handler of a driver.
 * This function:
 * 1) verifies the passed buffer,
 * 2) if necessary, calls buf_prepare callback in the driver (if provided), in
 *    which driver-specific buffer initialization can be performed,
 * 3) if streaming is on, queues the buffer in driver by the means of buf_queue
 *    callback for processing.
 *
 * The return values from this function are intended to be directly returned
 * from vidioc_qbuf handler in driver.
 */
int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
{
	return vb2_queue_or_prepare_buf(q, b, "qbuf", __vb2_qbuf);
}
EXPORT_SYMBOL_GPL(vb2_qbuf);

/**
 * __vb2_wait_for_done_vb() - wait for a buffer to become available
 * for dequeuing
 *
 * Will sleep if required for nonblocking == false.
 */
static int __vb2_wait_for_done_vb(struct vb2_queue *q, int nonblocking)
{
	/*
	 * All operations on vb_done_list are performed under done_lock
	 * spinlock protection. However, buffers may be removed from
	 * it and returned to userspace only while holding both driver's
	 * lock and the done_lock spinlock. Thus we can be sure that as
	 * long as we hold the driver's lock, the list will remain not
	 * empty if list_empty() check succeeds.
	 */

	for (;;) {
		int ret;

		if (!q->streaming) {
			dprintk(1, "Streaming off, will not wait for buffers\n");
			return -EINVAL;
		}

		if (!list_empty(&q->done_list)) {
			/*
			 * Found a buffer that we were waiting for.
			 */
			break;
		}

		if (nonblocking) {
			dprintk(1, "Nonblocking and no buffers to dequeue, "
								"will not wait\n");
			return -EAGAIN;
		}

		/*
		 * We are streaming and blocking, wait for another buffer to
		 * become ready or for streamoff. Driver's lock is released to
		 * allow streamoff or qbuf to be called while waiting.
		 */
		call_qop(q, wait_prepare, q);

		/*
		 * All locks have been released, it is safe to sleep now.
		 */
		dprintk(3, "Will sleep waiting for buffers\n");
		ret = wait_event_interruptible(q->done_wq,
				!list_empty(&q->done_list) || !q->streaming);

		/*
		 * We need to reevaluate both conditions again after reacquiring
		 * the locks or return an error if one occurred.
		 */
		call_qop(q, wait_finish, q);
		if (ret) {
			dprintk(1, "Sleep was interrupted\n");
			return ret;
		}
	}
	return 0;
}

/**
 * __vb2_get_done_vb() - get a buffer ready for dequeuing
 *
 * Will sleep if required for nonblocking == false.
 */
static int __vb2_get_done_vb(struct vb2_queue *q, struct vb2_buffer **vb,
				struct v4l2_buffer *b, int nonblocking)
{
	unsigned long flags;
	int ret;

	/*
	 * Wait for at least one buffer to become available on the done_list.
	 */
	ret = __vb2_wait_for_done_vb(q, nonblocking);
	if (ret)
		return ret;

	/*
	 * Driver's lock has been held since we last verified that done_list
	 * is not empty, so no need for another list_empty(done_list) check.
	 */
	spin_lock_irqsave(&q->done_lock, flags);
	*vb = list_first_entry(&q->done_list, struct vb2_buffer, done_entry);
	/*
	 * Only remove the buffer from done_list if v4l2_buffer can handle all
	 * the planes.
	 */
	ret = __verify_planes_array(*vb, b);
	if (!ret)
		list_del(&(*vb)->done_entry);
	spin_unlock_irqrestore(&q->done_lock, flags);

	return ret;
}

/**
 * vb2_wait_for_all_buffers() - wait until all buffers are given back to vb2
 * @q:		videobuf2 queue
 *
 * This function will wait until all buffers that have been given to the driver
 * by buf_queue() are given back to vb2 with vb2_buffer_done(). It doesn't call
 * wait_prepare, wait_finish pair. It is intended to be called with all locks
 * taken, for example from stop_streaming() callback.
 */
int vb2_wait_for_all_buffers(struct vb2_queue *q)
{
	if (!q->streaming) {
		dprintk(1, "Streaming off, will not wait for buffers\n");
		return -EINVAL;
	}

	wait_event(q->done_wq, !atomic_read(&q->queued_count));
	return 0;
}
EXPORT_SYMBOL_GPL(vb2_wait_for_all_buffers);

/**
 * __vb2_dqbuf() - bring back the buffer to the DEQUEUED state
 */
static void __vb2_dqbuf(struct vb2_buffer *vb)
{
	struct vb2_queue *q = vb->vb2_queue;
	unsigned int i;

	/* nothing to do if the buffer is already dequeued */
	if (vb->state == VB2_BUF_STATE_DEQUEUED)
		return;

	vb->state = VB2_BUF_STATE_DEQUEUED;

	/* unmap DMABUF buffer */
	if (q->memory == V4L2_MEMORY_DMABUF)
		for (i = 0; i < vb->num_planes; ++i) {
			if (!vb->planes[i].dbuf_mapped)
				continue;
			call_memop(q, unmap_dmabuf, vb->planes[i].mem_priv);
			vb->planes[i].dbuf_mapped = 0;
		}
}

/**
 * vb2_dqbuf() - Dequeue a buffer to the userspace
 * @q:		videobuf2 queue
 * @b:		buffer structure passed from userspace to vidioc_dqbuf handler
 *		in driver
 * @nonblocking: if true, this call will not sleep waiting for a buffer if no
 *		 buffers ready for dequeuing are present. Normally the driver
 *		 would be passing (file->f_flags & O_NONBLOCK) here
 *
 * Should be called from vidioc_dqbuf ioctl handler of a driver.
 * This function:
 * 1) verifies the passed buffer,
 * 2) calls buf_finish callback in the driver (if provided), in which
 *    driver can perform any additional operations that may be required before
 *    returning the buffer to userspace, such as cache sync,
 * 3) the buffer struct members are filled with relevant information for
 *    the userspace.
 *
 * The return values from this function are intended to be directly returned
 * from vidioc_dqbuf handler in driver.
 */
int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking)
{
	struct vb2_buffer *vb = NULL;
	int ret;

	if (q->fileio) {
		dprintk(1, "dqbuf: file io in progress\n");
		return -EBUSY;
	}

	if (b->type != q->type) {
		dprintk(1, "dqbuf: invalid buffer type\n");
		return -EINVAL;
	}
	ret = __vb2_get_done_vb(q, &vb, b, nonblocking);
	if (ret < 0)
		return ret;

	ret = call_qop(q, buf_finish, vb);
	if (ret) {
		dprintk(1, "dqbuf: buffer finish failed\n");
		return ret;
	}

	switch (vb->state) {
	case VB2_BUF_STATE_DONE:
		dprintk(3, "dqbuf: Returning done buffer\n");
		break;
	case VB2_BUF_STATE_ERROR:
		dprintk(3, "dqbuf: Returning done buffer with errors\n");
		break;
	default:
		dprintk(1, "dqbuf: Invalid buffer state\n");
		return -EINVAL;
	}

	/* Fill buffer information for the userspace */
	__fill_v4l2_buffer(vb, b);
	/* Remove from videobuf queue */
	list_del(&vb->queued_entry);
	/* go back to dequeued state */
	__vb2_dqbuf(vb);

	dprintk(1, "dqbuf of buffer %d, with state %d\n",
			vb->v4l2_buf.index, vb->state);

	return 0;
}
EXPORT_SYMBOL_GPL(vb2_dqbuf);

/**
 * __vb2_queue_cancel() - cancel and stop (pause) streaming
 *
 * Removes all queued buffers from driver's queue and all buffers queued by
 * userspace from videobuf's queue. Returns to state after reqbufs.
 */
static void __vb2_queue_cancel(struct vb2_queue *q)
{
	unsigned int i;

	/*
	 * Tell driver to stop all transactions and release all queued
	 * buffers.
	 */
	if (q->streaming)
		call_qop(q, stop_streaming, q);
	q->streaming = 0;

	/*
	 * Remove all buffers from videobuf's list...
	 */
	INIT_LIST_HEAD(&q->queued_list);
	/*
	 * ...and done list; userspace will not receive any buffers it
	 * has not already dequeued before initiating cancel.
	 */
	INIT_LIST_HEAD(&q->done_list);
	atomic_set(&q->queued_count, 0);
	wake_up_all(&q->done_wq);

	/*
	 * Reinitialize all buffers for next use.
	 */
	for (i = 0; i < q->num_buffers; ++i)
		__vb2_dqbuf(q->bufs[i]);
}

/**
 * vb2_streamon - start streaming
 * @q:		videobuf2 queue
 * @type:	type argument passed from userspace to vidioc_streamon handler
 *
 * Should be called from vidioc_streamon handler of a driver.
 * This function:
 * 1) verifies current state
 * 2) passes any previously queued buffers to the driver and starts streaming
 *
 * The return values from this function are intended to be directly returned
 * from vidioc_streamon handler in the driver.
 */
int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type)
{
	struct vb2_buffer *vb;
	int ret;

	if (q->fileio) {
		dprintk(1, "streamon: file io in progress\n");
		return -EBUSY;
	}

	if (type != q->type) {
		dprintk(1, "streamon: invalid stream type\n");
		return -EINVAL;
	}

	if (q->streaming) {
		dprintk(1, "streamon: already streaming\n");
		return -EBUSY;
	}

	/*
	 * If any buffers were queued before streamon,
	 * we can now pass them to driver for processing.
	 */
	list_for_each_entry(vb, &q->queued_list, queued_entry)
		__enqueue_in_driver(vb);

	/*
	 * Let driver notice that streaming state has been enabled.
	 */
	ret = call_qop(q, start_streaming, q, atomic_read(&q->queued_count));
	if (ret) {
		dprintk(1, "streamon: driver refused to start streaming\n");
		__vb2_queue_cancel(q);
		return ret;
	}

	q->streaming = 1;

	dprintk(3, "Streamon successful\n");
	return 0;
}
EXPORT_SYMBOL_GPL(vb2_streamon);


/**
 * vb2_streamoff - stop streaming
 * @q:		videobuf2 queue
 * @type:	type argument passed from userspace to vidioc_streamoff handler
 *
 * Should be called from vidioc_streamoff handler of a driver.
 * This function:
 * 1) verifies current state,
 * 2) stop streaming and dequeues any queued buffers, including those previously
 *    passed to the driver (after waiting for the driver to finish).
 *
 * This call can be used for pausing playback.
 * The return values from this function are intended to be directly returned
 * from vidioc_streamoff handler in the driver
 */
int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type)
{
	if (q->fileio) {
		dprintk(1, "streamoff: file io in progress\n");
		return -EBUSY;
	}

	if (type != q->type) {
		dprintk(1, "streamoff: invalid stream type\n");
		return -EINVAL;
	}

	if (!q->streaming) {
		dprintk(1, "streamoff: not streaming\n");
		return -EINVAL;
	}

	/*
	 * Cancel will pause streaming and remove all buffers from the driver
	 * and videobuf, effectively returning control over them to userspace.
	 */
	__vb2_queue_cancel(q);

	dprintk(3, "Streamoff successful\n");
	return 0;
}
EXPORT_SYMBOL_GPL(vb2_streamoff);

/**
 * __find_plane_by_offset() - find plane associated with the given offset off
 */
static int __find_plane_by_offset(struct vb2_queue *q, unsigned long off,
			unsigned int *_buffer, unsigned int *_plane)
{
	struct vb2_buffer *vb;
	unsigned int buffer, plane;

	/*
	 * Go over all buffers and their planes, comparing the given offset
	 * with an offset assigned to each plane. If a match is found,
	 * return its buffer and plane numbers.
	 */
	for (buffer = 0; buffer < q->num_buffers; ++buffer) {
		vb = q->bufs[buffer];

		for (plane = 0; plane < vb->num_planes; ++plane) {
			if (vb->v4l2_planes[plane].m.mem_offset == off) {
				*_buffer = buffer;
				*_plane = plane;
				return 0;
			}
		}
	}

	return -EINVAL;
}

/**
 * vb2_expbuf() - Export a buffer as a file descriptor
 * @q:		videobuf2 queue
 * @eb:		export buffer structure passed from userspace to vidioc_expbuf
 *		handler in driver
 *
 * The return values from this function are intended to be directly returned
 * from vidioc_expbuf handler in driver.
 */
int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb)
{
	struct vb2_buffer *vb = NULL;
	struct vb2_plane *vb_plane;
	int ret;
	struct dma_buf *dbuf;

	if (q->memory != V4L2_MEMORY_MMAP) {
		dprintk(1, "Queue is not currently set up for mmap\n");
		return -EINVAL;
	}

	if (!q->mem_ops->get_dmabuf) {
		dprintk(1, "Queue does not support DMA buffer exporting\n");
		return -EINVAL;
	}

	if (eb->flags & ~O_CLOEXEC) {
		dprintk(1, "Queue does support only O_CLOEXEC flag\n");
		return -EINVAL;
	}

	if (eb->type != q->type) {
		dprintk(1, "qbuf: invalid buffer type\n");
		return -EINVAL;
	}

	if (eb->index >= q->num_buffers) {
		dprintk(1, "buffer index out of range\n");
		return -EINVAL;
	}

	vb = q->bufs[eb->index];

	if (eb->plane >= vb->num_planes) {
		dprintk(1, "buffer plane out of range\n");
		return -EINVAL;
	}

	vb_plane = &vb->planes[eb->plane];

	dbuf = call_memop(q, get_dmabuf, vb_plane->mem_priv);
	if (IS_ERR_OR_NULL(dbuf)) {
		dprintk(1, "Failed to export buffer %d, plane %d\n",
			eb->index, eb->plane);
		return -EINVAL;
	}

	ret = dma_buf_fd(dbuf, eb->flags);
	if (ret < 0) {
		dprintk(3, "buffer %d, plane %d failed to export (%d)\n",
			eb->index, eb->plane, ret);
		dma_buf_put(dbuf);
		return ret;
	}

	dprintk(3, "buffer %d, plane %d exported as %d descriptor\n",
		eb->index, eb->plane, ret);
	eb->fd = ret;

	return 0;
}
EXPORT_SYMBOL_GPL(vb2_expbuf);

/**
 * vb2_mmap() - map video buffers into application address space
 * @q:		videobuf2 queue
 * @vma:	vma passed to the mmap file operation handler in the driver
 *
 * Should be called from mmap file operation handler of a driver.
 * This function maps one plane of one of the available video buffers to
 * userspace. To map whole video memory allocated on reqbufs, this function
 * has to be called once per each plane per each buffer previously allocated.
 *
 * When the userspace application calls mmap, it passes to it an offset returned
 * to it earlier by the means of vidioc_querybuf handler. That offset acts as
 * a "cookie", which is then used to identify the plane to be mapped.
 * This function finds a plane with a matching offset and a mapping is performed
 * by the means of a provided memory operation.
 *
 * The return values from this function are intended to be directly returned
 * from the mmap handler in driver.
 */
int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
{
	unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
	struct vb2_buffer *vb;
	unsigned int buffer, plane;
	int ret;
	unsigned long length;

	if (q->memory != V4L2_MEMORY_MMAP) {
		dprintk(1, "Queue is not currently set up for mmap\n");
		return -EINVAL;
	}

	/*
	 * Check memory area access mode.
	 */
	if (!(vma->vm_flags & VM_SHARED)) {
		dprintk(1, "Invalid vma flags, VM_SHARED needed\n");
		return -EINVAL;
	}
	if (V4L2_TYPE_IS_OUTPUT(q->type)) {
		if (!(vma->vm_flags & VM_WRITE)) {
			dprintk(1, "Invalid vma flags, VM_WRITE needed\n");
			return -EINVAL;
		}
	} else {
		if (!(vma->vm_flags & VM_READ)) {
			dprintk(1, "Invalid vma flags, VM_READ needed\n");
			return -EINVAL;
		}
	}

	/*
	 * Find the plane corresponding to the offset passed by userspace.
	 */
	ret = __find_plane_by_offset(q, off, &buffer, &plane);
	if (ret)
		return ret;

	vb = q->bufs[buffer];

	/*
	 * MMAP requires page_aligned buffers.
	 * The buffer length was page_aligned at __vb2_buf_mem_alloc(),
	 * so, we need to do the same here.
	 */
	length = PAGE_ALIGN(vb->v4l2_planes[plane].length);
	if (length < (vma->vm_end - vma->vm_start)) {
		dprintk(1,
			"MMAP invalid, as it would overflow buffer length\n");
		return -EINVAL;
	}

	ret = call_memop(q, mmap, vb->planes[plane].mem_priv, vma);
	if (ret)
		return ret;

	dprintk(3, "Buffer %d, plane %d successfully mapped\n", buffer, plane);
	return 0;
}
EXPORT_SYMBOL_GPL(vb2_mmap);

#ifndef CONFIG_MMU
unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
				    unsigned long addr,
				    unsigned long len,
				    unsigned long pgoff,
				    unsigned long flags)
{
	unsigned long off = pgoff << PAGE_SHIFT;
	struct vb2_buffer *vb;
	unsigned int buffer, plane;
	int ret;

	if (q->memory != V4L2_MEMORY_MMAP) {
		dprintk(1, "Queue is not currently set up for mmap\n");
		return -EINVAL;
	}

	/*
	 * Find the plane corresponding to the offset passed by userspace.
	 */
	ret = __find_plane_by_offset(q, off, &buffer, &plane);
	if (ret)
		return ret;

	vb = q->bufs[buffer];

	return (unsigned long)vb2_plane_vaddr(vb, plane);
}
EXPORT_SYMBOL_GPL(vb2_get_unmapped_area);
#endif

static int __vb2_init_fileio(struct vb2_queue *q, int read);
static int __vb2_cleanup_fileio(struct vb2_queue *q);

/**
 * vb2_poll() - implements poll userspace operation
 * @q:		videobuf2 queue
 * @file:	file argument passed to the poll file operation handler
 * @wait:	wait argument passed to the poll file operation handler
 *
 * This function implements poll file operation handler for a driver.
 * For CAPTURE queues, if a buffer is ready to be dequeued, the userspace will
 * be informed that the file descriptor of a video device is available for
 * reading.
 * For OUTPUT queues, if a buffer is ready to be dequeued, the file descriptor
 * will be reported as available for writing.
 *
 * If the driver uses struct v4l2_fh, then vb2_poll() will also check for any
 * pending events.
 *
 * The return values from this function are intended to be directly returned
 * from poll handler in driver.
 */
unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait)
{
	struct video_device *vfd = video_devdata(file);
	unsigned long req_events = poll_requested_events(wait);
	struct vb2_buffer *vb = NULL;
	unsigned int res = 0;
	unsigned long flags;

	if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) {
		struct v4l2_fh *fh = file->private_data;

		if (v4l2_event_pending(fh))
			res = POLLPRI;
		else if (req_events & POLLPRI)
			poll_wait(file, &fh->wait, wait);
	}

	if (!V4L2_TYPE_IS_OUTPUT(q->type) && !(req_events & (POLLIN | POLLRDNORM)))
		return res;
	if (V4L2_TYPE_IS_OUTPUT(q->type) && !(req_events & (POLLOUT | POLLWRNORM)))
		return res;

	/*
	 * Start file I/O emulator only if streaming API has not been used yet.
	 */
	if (q->num_buffers == 0 && q->fileio == NULL) {
		if (!V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_READ) &&
				(req_events & (POLLIN | POLLRDNORM))) {
			if (__vb2_init_fileio(q, 1))
				return res | POLLERR;
		}
		if (V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_WRITE) &&
				(req_events & (POLLOUT | POLLWRNORM))) {
			if (__vb2_init_fileio(q, 0))
				return res | POLLERR;
			/*
			 * Write to OUTPUT queue can be done immediately.
			 */
			return res | POLLOUT | POLLWRNORM;
		}
	}

	/*
	 * There is nothing to wait for if no buffers have already been queued.
	 */
	if (list_empty(&q->queued_list))
		return res | POLLERR;

	if (list_empty(&q->done_list))
		poll_wait(file, &q->done_wq, wait);

	/*
	 * Take first buffer available for dequeuing.
	 */
	spin_lock_irqsave(&q->done_lock, flags);
	if (!list_empty(&q->done_list))
		vb = list_first_entry(&q->done_list, struct vb2_buffer,
					done_entry);
	spin_unlock_irqrestore(&q->done_lock, flags);

	if (vb && (vb->state == VB2_BUF_STATE_DONE
			|| vb->state == VB2_BUF_STATE_ERROR)) {
		return (V4L2_TYPE_IS_OUTPUT(q->type)) ?
				res | POLLOUT | POLLWRNORM :
				res | POLLIN | POLLRDNORM;
	}
	return res;
}
EXPORT_SYMBOL_GPL(vb2_poll);

/**
 * vb2_queue_init() - initialize a videobuf2 queue
 * @q:		videobuf2 queue; this structure should be allocated in driver
 *
 * The vb2_queue structure should be allocated by the driver. The driver is
 * responsible of clearing it's content and setting initial values for some
 * required entries before calling this function.
 * q->ops, q->mem_ops, q->type and q->io_modes are mandatory. Please refer
 * to the struct vb2_queue description in include/media/videobuf2-core.h
 * for more information.
 */
int vb2_queue_init(struct vb2_queue *q)
{
	/*
	 * Sanity check
	 */
	if (WARN_ON(!q)			  ||
	    WARN_ON(!q->ops)		  ||
	    WARN_ON(!q->mem_ops)	  ||
	    WARN_ON(!q->type)		  ||
	    WARN_ON(!q->io_modes)	  ||
	    WARN_ON(!q->ops->queue_setup) ||
	    WARN_ON(!q->ops->buf_queue)   ||
	    WARN_ON(q->timestamp_type & ~V4L2_BUF_FLAG_TIMESTAMP_MASK))
		return -EINVAL;

	/* Warn that the driver should choose an appropriate timestamp type */
	WARN_ON(q->timestamp_type == V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN);

	INIT_LIST_HEAD(&q->queued_list);
	INIT_LIST_HEAD(&q->done_list);
	spin_lock_init(&q->done_lock);
	init_waitqueue_head(&q->done_wq);

	if (q->buf_struct_size == 0)
		q->buf_struct_size = sizeof(struct vb2_buffer);

	return 0;
}
EXPORT_SYMBOL_GPL(vb2_queue_init);

/**
 * vb2_queue_release() - stop streaming, release the queue and free memory
 * @q:		videobuf2 queue
 *
 * This function stops streaming and performs necessary clean ups, including
 * freeing video buffer memory. The driver is responsible for freeing
 * the vb2_queue structure itself.
 */
void vb2_queue_release(struct vb2_queue *q)
{
	__vb2_cleanup_fileio(q);
	__vb2_queue_cancel(q);
	__vb2_queue_free(q, q->num_buffers);
}
EXPORT_SYMBOL_GPL(vb2_queue_release);

/**
 * struct vb2_fileio_buf - buffer context used by file io emulator
 *
 * vb2 provides a compatibility layer and emulator of file io (read and
 * write) calls on top of streaming API. This structure is used for
 * tracking context related to the buffers.
 */
struct vb2_fileio_buf {
	void *vaddr;
	unsigned int size;
	unsigned int pos;
	unsigned int queued:1;
};

/**
 * struct vb2_fileio_data - queue context used by file io emulator
 *
 * vb2 provides a compatibility layer and emulator of file io (read and
 * write) calls on top of streaming API. For proper operation it required
 * this structure to save the driver state between each call of the read
 * or write function.
 */
struct vb2_fileio_data {
	struct v4l2_requestbuffers req;
	struct v4l2_buffer b;
	struct vb2_fileio_buf bufs[VIDEO_MAX_FRAME];
	unsigned int index;
	unsigned int q_count;
	unsigned int dq_count;
	unsigned int flags;
};

/**
 * __vb2_init_fileio() - initialize file io emulator
 * @q:		videobuf2 queue
 * @read:	mode selector (1 means read, 0 means write)
 */
static int __vb2_init_fileio(struct vb2_queue *q, int read)
{
	struct vb2_fileio_data *fileio;
	int i, ret;
	unsigned int count = 0;

	/*
	 * Sanity check
	 */
	if ((read && !(q->io_modes & VB2_READ)) ||
	   (!read && !(q->io_modes & VB2_WRITE)))
		BUG();

	/*
	 * Check if device supports mapping buffers to kernel virtual space.
	 */
	if (!q->mem_ops->vaddr)
		return -EBUSY;

	/*
	 * Check if streaming api has not been already activated.
	 */
	if (q->streaming || q->num_buffers > 0)
		return -EBUSY;

	/*
	 * Start with count 1, driver can increase it in queue_setup()
	 */
	count = 1;

	dprintk(3, "setting up file io: mode %s, count %d, flags %08x\n",
		(read) ? "read" : "write", count, q->io_flags);

	fileio = kzalloc(sizeof(struct vb2_fileio_data), GFP_KERNEL);
	if (fileio == NULL)
		return -ENOMEM;

	fileio->flags = q->io_flags;

	/*
	 * Request buffers and use MMAP type to force driver
	 * to allocate buffers by itself.
	 */
	fileio->req.count = count;
	fileio->req.memory = V4L2_MEMORY_MMAP;
	fileio->req.type = q->type;
	ret = vb2_reqbufs(q, &fileio->req);
	if (ret)
		goto err_kfree;

	/*
	 * Check if plane_count is correct
	 * (multiplane buffers are not supported).
	 */
	if (q->bufs[0]->num_planes != 1) {
		ret = -EBUSY;
		goto err_reqbufs;
	}

	/*
	 * Get kernel address of each buffer.
	 */
	for (i = 0; i < q->num_buffers; i++) {
		fileio->bufs[i].vaddr = vb2_plane_vaddr(q->bufs[i], 0);
		if (fileio->bufs[i].vaddr == NULL) {
			ret = -EINVAL;
			goto err_reqbufs;
		}
		fileio->bufs[i].size = vb2_plane_size(q->bufs[i], 0);
	}

	/*
	 * Read mode requires pre queuing of all buffers.
	 */
	if (read) {
		/*
		 * Queue all buffers.
		 */
		for (i = 0; i < q->num_buffers; i++) {
			struct v4l2_buffer *b = &fileio->b;
			memset(b, 0, sizeof(*b));
			b->type = q->type;
			b->memory = q->memory;
			b->index = i;
			ret = vb2_qbuf(q, b);
			if (ret)
				goto err_reqbufs;
			fileio->bufs[i].queued = 1;
		}

		/*
		 * Start streaming.
		 */
		ret = vb2_streamon(q, q->type);
		if (ret)
			goto err_reqbufs;
	}

	q->fileio = fileio;

	return ret;

err_reqbufs:
	fileio->req.count = 0;
	vb2_reqbufs(q, &fileio->req);

err_kfree:
	kfree(fileio);
	return ret;
}

/**
 * __vb2_cleanup_fileio() - free resourced used by file io emulator
 * @q:		videobuf2 queue
 */
static int __vb2_cleanup_fileio(struct vb2_queue *q)
{
	struct vb2_fileio_data *fileio = q->fileio;

	if (fileio) {
		/*
		 * Hack fileio context to enable direct calls to vb2 ioctl
		 * interface.
		 */
		q->fileio = NULL;

		vb2_streamoff(q, q->type);
		fileio->req.count = 0;
		vb2_reqbufs(q, &fileio->req);
		kfree(fileio);
		dprintk(3, "file io emulator closed\n");
	}
	return 0;
}

/**
 * __vb2_perform_fileio() - perform a single file io (read or write) operation
 * @q:		videobuf2 queue
 * @data:	pointed to target userspace buffer
 * @count:	number of bytes to read or write
 * @ppos:	file handle position tracking pointer
 * @nonblock:	mode selector (1 means blocking calls, 0 means nonblocking)
 * @read:	access mode selector (1 means read, 0 means write)
 */
static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_t count,
		loff_t *ppos, int nonblock, int read)
{
	struct vb2_fileio_data *fileio;
	struct vb2_fileio_buf *buf;
	int ret, index;

	dprintk(3, "file io: mode %s, offset %ld, count %zd, %sblocking\n",
		read ? "read" : "write", (long)*ppos, count,
		nonblock ? "non" : "");

	if (!data)
		return -EINVAL;

	/*
	 * Initialize emulator on first call.
	 */
	if (!q->fileio) {
		ret = __vb2_init_fileio(q, read);
		dprintk(3, "file io: vb2_init_fileio result: %d\n", ret);
		if (ret)
			return ret;
	}
	fileio = q->fileio;

	/*
	 * Hack fileio context to enable direct calls to vb2 ioctl interface.
	 * The pointer will be restored before returning from this function.
	 */
	q->fileio = NULL;

	index = fileio->index;
	buf = &fileio->bufs[index];

	/*
	 * Check if we need to dequeue the buffer.
	 */
	if (buf->queued) {
		struct vb2_buffer *vb;

		/*
		 * Call vb2_dqbuf to get buffer back.
		 */
		memset(&fileio->b, 0, sizeof(fileio->b));
		fileio->b.type = q->type;
		fileio->b.memory = q->memory;
		fileio->b.index = index;
		ret = vb2_dqbuf(q, &fileio->b, nonblock);
		dprintk(5, "file io: vb2_dqbuf result: %d\n", ret);
		if (ret)
			goto end;
		fileio->dq_count += 1;

		/*
		 * Get number of bytes filled by the driver
		 */
		vb = q->bufs[index];
		buf->size = vb2_get_plane_payload(vb, 0);
		buf->queued = 0;
	}

	/*
	 * Limit count on last few bytes of the buffer.
	 */
	if (buf->pos + count > buf->size) {
		count = buf->size - buf->pos;
		dprintk(5, "reducing read count: %zd\n", count);
	}

	/*
	 * Transfer data to userspace.
	 */
	dprintk(3, "file io: copying %zd bytes - buffer %d, offset %u\n",
		count, index, buf->pos);
	if (read)
		ret = copy_to_user(data, buf->vaddr + buf->pos, count);
	else
		ret = copy_from_user(buf->vaddr + buf->pos, data, count);
	if (ret) {
		dprintk(3, "file io: error copying data\n");
		ret = -EFAULT;
		goto end;
	}

	/*
	 * Update counters.
	 */
	buf->pos += count;
	*ppos += count;

	/*
	 * Queue next buffer if required.
	 */
	if (buf->pos == buf->size ||
	   (!read && (fileio->flags & VB2_FILEIO_WRITE_IMMEDIATELY))) {
		/*
		 * Check if this is the last buffer to read.
		 */
		if (read && (fileio->flags & VB2_FILEIO_READ_ONCE) &&
		    fileio->dq_count == 1) {
			dprintk(3, "file io: read limit reached\n");
			/*
			 * Restore fileio pointer and release the context.
			 */
			q->fileio = fileio;
			return __vb2_cleanup_fileio(q);
		}

		/*
		 * Call vb2_qbuf and give buffer to the driver.
		 */
		memset(&fileio->b, 0, sizeof(fileio->b));
		fileio->b.type = q->type;
		fileio->b.memory = q->memory;
		fileio->b.index = index;
		fileio->b.bytesused = buf->pos;
		ret = vb2_qbuf(q, &fileio->b);
		dprintk(5, "file io: vb2_dbuf result: %d\n", ret);
		if (ret)
			goto end;

		/*
		 * Buffer has been queued, update the status
		 */
		buf->pos = 0;
		buf->queued = 1;
		buf->size = q->bufs[0]->v4l2_planes[0].length;
		fileio->q_count += 1;

		/*
		 * Switch to the next buffer
		 */
		fileio->index = (index + 1) % q->num_buffers;

		/*
		 * Start streaming if required.
		 */
		if (!read && !q->streaming) {
			ret = vb2_streamon(q, q->type);
			if (ret)
				goto end;
		}
	}

	/*
	 * Return proper number of bytes processed.
	 */
	if (ret == 0)
		ret = count;
end:
	/*
	 * Restore the fileio context and block vb2 ioctl interface.
	 */
	q->fileio = fileio;
	return ret;
}

size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
		loff_t *ppos, int nonblocking)
{
	return __vb2_perform_fileio(q, data, count, ppos, nonblocking, 1);
}
EXPORT_SYMBOL_GPL(vb2_read);

size_t vb2_write(struct vb2_queue *q, char __user *data, size_t count,
		loff_t *ppos, int nonblocking)
{
	return __vb2_perform_fileio(q, data, count, ppos, nonblocking, 0);
}
EXPORT_SYMBOL_GPL(vb2_write);


/*
 * The following functions are not part of the vb2 core API, but are helper
 * functions that plug into struct v4l2_ioctl_ops, struct v4l2_file_operations
 * and struct vb2_ops.
 * They contain boilerplate code that most if not all drivers have to do
 * and so they simplify the driver code.
 */

/* The queue is busy if there is a owner and you are not that owner. */
static inline bool vb2_queue_is_busy(struct video_device *vdev, struct file *file)
{
	return vdev->queue->owner && vdev->queue->owner != file->private_data;
}

/* vb2 ioctl helpers */

int vb2_ioctl_reqbufs(struct file *file, void *priv,
			  struct v4l2_requestbuffers *p)
{
	struct video_device *vdev = video_devdata(file);
	int res = __verify_memory_type(vdev->queue, p->memory, p->type);

	if (res)
		return res;
	if (vb2_queue_is_busy(vdev, file))
		return -EBUSY;
	res = __reqbufs(vdev->queue, p);
	/* If count == 0, then the owner has released all buffers and he
	   is no longer owner of the queue. Otherwise we have a new owner. */
	if (res == 0)
		vdev->queue->owner = p->count ? file->private_data : NULL;
	return res;
}
EXPORT_SYMBOL_GPL(vb2_ioctl_reqbufs);

int vb2_ioctl_create_bufs(struct file *file, void *priv,
			  struct v4l2_create_buffers *p)
{
	struct video_device *vdev = video_devdata(file);
	int res = __verify_memory_type(vdev->queue, p->memory, p->format.type);

	p->index = vdev->queue->num_buffers;
	/* If count == 0, then just check if memory and type are valid.
	   Any -EBUSY result from __verify_memory_type can be mapped to 0. */
	if (p->count == 0)
		return res != -EBUSY ? res : 0;
	if (res)
		return res;
	if (vb2_queue_is_busy(vdev, file))
		return -EBUSY;
	res = __create_bufs(vdev->queue, p);
	if (res == 0)
		vdev->queue->owner = file->private_data;
	return res;
}
EXPORT_SYMBOL_GPL(vb2_ioctl_create_bufs);

int vb2_ioctl_prepare_buf(struct file *file, void *priv,
			  struct v4l2_buffer *p)
{
	struct video_device *vdev = video_devdata(file);

	if (vb2_queue_is_busy(vdev, file))
		return -EBUSY;
	return vb2_prepare_buf(vdev->queue, p);
}
EXPORT_SYMBOL_GPL(vb2_ioctl_prepare_buf);

int vb2_ioctl_querybuf(struct file *file, void *priv, struct v4l2_buffer *p)
{
	struct video_device *vdev = video_devdata(file);

	/* No need to call vb2_queue_is_busy(), anyone can query buffers. */
	return vb2_querybuf(vdev->queue, p);
}
EXPORT_SYMBOL_GPL(vb2_ioctl_querybuf);

int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p)
{
	struct video_device *vdev = video_devdata(file);

	if (vb2_queue_is_busy(vdev, file))
		return -EBUSY;
	return vb2_qbuf(vdev->queue, p);
}
EXPORT_SYMBOL_GPL(vb2_ioctl_qbuf);

int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p)
{
	struct video_device *vdev = video_devdata(file);

	if (vb2_queue_is_busy(vdev, file))
		return -EBUSY;
	return vb2_dqbuf(vdev->queue, p, file->f_flags & O_NONBLOCK);
}
EXPORT_SYMBOL_GPL(vb2_ioctl_dqbuf);

int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i)
{
	struct video_device *vdev = video_devdata(file);

	if (vb2_queue_is_busy(vdev, file))
		return -EBUSY;
	return vb2_streamon(vdev->queue, i);
}
EXPORT_SYMBOL_GPL(vb2_ioctl_streamon);

int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i)
{
	struct video_device *vdev = video_devdata(file);

	if (vb2_queue_is_busy(vdev, file))
		return -EBUSY;
	return vb2_streamoff(vdev->queue, i);
}
EXPORT_SYMBOL_GPL(vb2_ioctl_streamoff);

int vb2_ioctl_expbuf(struct file *file, void *priv, struct v4l2_exportbuffer *p)
{
	struct video_device *vdev = video_devdata(file);

	if (vb2_queue_is_busy(vdev, file))
		return -EBUSY;
	return vb2_expbuf(vdev->queue, p);
}
EXPORT_SYMBOL_GPL(vb2_ioctl_expbuf);

/* v4l2_file_operations helpers */

int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct video_device *vdev = video_devdata(file);
	struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
	int err;

	if (lock && mutex_lock_interruptible(lock))
		return -ERESTARTSYS;
	err = vb2_mmap(vdev->queue, vma);
	if (lock)
		mutex_unlock(lock);
	return err;
}
EXPORT_SYMBOL_GPL(vb2_fop_mmap);

int vb2_fop_release(struct file *file)
{
	struct video_device *vdev = video_devdata(file);

	if (file->private_data == vdev->queue->owner) {
		vb2_queue_release(vdev->queue);
		vdev->queue->owner = NULL;
	}
	return v4l2_fh_release(file);
}
EXPORT_SYMBOL_GPL(vb2_fop_release);

ssize_t vb2_fop_write(struct file *file, char __user *buf,
		size_t count, loff_t *ppos)
{
	struct video_device *vdev = video_devdata(file);
	struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
	int err = -EBUSY;

	if (lock && mutex_lock_interruptible(lock))
		return -ERESTARTSYS;
	if (vb2_queue_is_busy(vdev, file))
		goto exit;
	err = vb2_write(vdev->queue, buf, count, ppos,
		       file->f_flags & O_NONBLOCK);
	if (vdev->queue->fileio)
		vdev->queue->owner = file->private_data;
exit:
	if (lock)
		mutex_unlock(lock);
	return err;
}
EXPORT_SYMBOL_GPL(vb2_fop_write);

ssize_t vb2_fop_read(struct file *file, char __user *buf,
		size_t count, loff_t *ppos)
{
	struct video_device *vdev = video_devdata(file);
	struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
	int err = -EBUSY;

	if (lock && mutex_lock_interruptible(lock))
		return -ERESTARTSYS;
	if (vb2_queue_is_busy(vdev, file))
		goto exit;
	err = vb2_read(vdev->queue, buf, count, ppos,
		       file->f_flags & O_NONBLOCK);
	if (vdev->queue->fileio)
		vdev->queue->owner = file->private_data;
exit:
	if (lock)
		mutex_unlock(lock);
	return err;
}
EXPORT_SYMBOL_GPL(vb2_fop_read);

unsigned int vb2_fop_poll(struct file *file, poll_table *wait)
{
	struct video_device *vdev = video_devdata(file);
	struct vb2_queue *q = vdev->queue;
	struct mutex *lock = q->lock ? q->lock : vdev->lock;
	unsigned long req_events = poll_requested_events(wait);
	unsigned res;
	void *fileio;
	bool must_lock = false;

	/* Try to be smart: only lock if polling might start fileio,
	   otherwise locking will only introduce unwanted delays. */
	if (q->num_buffers == 0 && q->fileio == NULL) {
		if (!V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_READ) &&
				(req_events & (POLLIN | POLLRDNORM)))
			must_lock = true;
		else if (V4L2_TYPE_IS_OUTPUT(q->type) && (q->io_modes & VB2_WRITE) &&
				(req_events & (POLLOUT | POLLWRNORM)))
			must_lock = true;
	}

	/* If locking is needed, but this helper doesn't know how, then you
	   shouldn't be using this helper but you should write your own. */
	WARN_ON(must_lock && !lock);

	if (must_lock && lock && mutex_lock_interruptible(lock))
		return POLLERR;

	fileio = q->fileio;

	res = vb2_poll(vdev->queue, file, wait);

	/* If fileio was started, then we have a new queue owner. */
	if (must_lock && !fileio && q->fileio)
		q->owner = file->private_data;
	if (must_lock && lock)
		mutex_unlock(lock);
	return res;
}
EXPORT_SYMBOL_GPL(vb2_fop_poll);

#ifndef CONFIG_MMU
unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr,
		unsigned long len, unsigned long pgoff, unsigned long flags)
{
	struct video_device *vdev = video_devdata(file);
	struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
	int ret;

	if (lock && mutex_lock_interruptible(lock))
		return -ERESTARTSYS;
	ret = vb2_get_unmapped_area(vdev->queue, addr, len, pgoff, flags);
	if (lock)
		mutex_unlock(lock);
	return ret;
}
EXPORT_SYMBOL_GPL(vb2_fop_get_unmapped_area);
#endif

/* vb2_ops helpers. Only use if vq->lock is non-NULL. */

void vb2_ops_wait_prepare(struct vb2_queue *vq)
{
	mutex_unlock(vq->lock);
}
EXPORT_SYMBOL_GPL(vb2_ops_wait_prepare);

void vb2_ops_wait_finish(struct vb2_queue *vq)
{
	mutex_lock(vq->lock);
}
EXPORT_SYMBOL_GPL(vb2_ops_wait_finish);

MODULE_DESCRIPTION("Driver helper framework for Video for Linux 2");
MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>, Marek Szyprowski");
MODULE_LICENSE("GPL");