summaryrefslogtreecommitdiff
path: root/drivers/mtd/mtdcore.c
blob: 6217be2352864d998b29038b0a5ef4f91390ad03 (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
// SPDX-License-Identifier: GPL-2.0+
/*
 * Core registration and callback routines for MTD
 * drivers and users.
 *
 * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
 * Copyright © 2006      Red Hat UK Limited 
 *
 */

#ifndef __UBOOT__
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ptrace.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/major.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/ioctl.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/idr.h>
#include <linux/backing-dev.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#else
#include <linux/err.h>
#include <ubi_uboot.h>
#endif

#include <linux/log2.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>

#include "mtdcore.h"

#ifndef __UBOOT__
/*
 * backing device capabilities for non-mappable devices (such as NAND flash)
 * - permits private mappings, copies are taken of the data
 */
static struct backing_dev_info mtd_bdi_unmappable = {
	.capabilities	= BDI_CAP_MAP_COPY,
};

/*
 * backing device capabilities for R/O mappable devices (such as ROM)
 * - permits private mappings, copies are taken of the data
 * - permits non-writable shared mappings
 */
static struct backing_dev_info mtd_bdi_ro_mappable = {
	.capabilities	= (BDI_CAP_MAP_COPY | BDI_CAP_MAP_DIRECT |
			   BDI_CAP_EXEC_MAP | BDI_CAP_READ_MAP),
};

/*
 * backing device capabilities for writable mappable devices (such as RAM)
 * - permits private mappings, copies are taken of the data
 * - permits non-writable shared mappings
 */
static struct backing_dev_info mtd_bdi_rw_mappable = {
	.capabilities	= (BDI_CAP_MAP_COPY | BDI_CAP_MAP_DIRECT |
			   BDI_CAP_EXEC_MAP | BDI_CAP_READ_MAP |
			   BDI_CAP_WRITE_MAP),
};

static int mtd_cls_suspend(struct device *dev, pm_message_t state);
static int mtd_cls_resume(struct device *dev);

static struct class mtd_class = {
	.name = "mtd",
	.owner = THIS_MODULE,
	.suspend = mtd_cls_suspend,
	.resume = mtd_cls_resume,
};
#else
struct mtd_info *mtd_table[MAX_MTD_DEVICES];

#define MAX_IDR_ID	64

struct idr_layer {
	int	used;
	void	*ptr;
};

struct idr {
	struct idr_layer id[MAX_IDR_ID];
};

#define DEFINE_IDR(name)	struct idr name;

void idr_remove(struct idr *idp, int id)
{
	if (idp->id[id].used)
		idp->id[id].used = 0;

	return;
}
void *idr_find(struct idr *idp, int id)
{
	if (idp->id[id].used)
		return idp->id[id].ptr;

	return NULL;
}

void *idr_get_next(struct idr *idp, int *next)
{
	void *ret;
	int id = *next;

	ret = idr_find(idp, id);
	if (ret) {
		id ++;
		if (!idp->id[id].used)
			id = 0;
		*next = id;
	} else {
		*next = 0;
	}
	
	return ret;
}

int idr_alloc(struct idr *idp, void *ptr, int start, int end, gfp_t gfp_mask)
{
	struct idr_layer *idl;
	int i = 0;

	while (i < MAX_IDR_ID) {
		idl = &idp->id[i];
		if (idl->used == 0) {
			idl->used = 1;
			idl->ptr = ptr;
			return i;
		}
		i++;
	}
	return -ENOSPC;
}
#endif

static DEFINE_IDR(mtd_idr);

/* These are exported solely for the purpose of mtd_blkdevs.c. You
   should not use them for _anything_ else */
DEFINE_MUTEX(mtd_table_mutex);
EXPORT_SYMBOL_GPL(mtd_table_mutex);

struct mtd_info *__mtd_next_device(int i)
{
	return idr_get_next(&mtd_idr, &i);
}
EXPORT_SYMBOL_GPL(__mtd_next_device);

#ifndef __UBOOT__
static LIST_HEAD(mtd_notifiers);


#define MTD_DEVT(index) MKDEV(MTD_CHAR_MAJOR, (index)*2)

/* REVISIT once MTD uses the driver model better, whoever allocates
 * the mtd_info will probably want to use the release() hook...
 */
static void mtd_release(struct device *dev)
{
	struct mtd_info __maybe_unused *mtd = dev_get_drvdata(dev);
	dev_t index = MTD_DEVT(mtd->index);

	/* remove /dev/mtdXro node if needed */
	if (index)
		device_destroy(&mtd_class, index + 1);
}

static int mtd_cls_suspend(struct device *dev, pm_message_t state)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);

	return mtd ? mtd_suspend(mtd) : 0;
}

static int mtd_cls_resume(struct device *dev)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);

	if (mtd)
		mtd_resume(mtd);
	return 0;
}

static ssize_t mtd_type_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);
	char *type;

	switch (mtd->type) {
	case MTD_ABSENT:
		type = "absent";
		break;
	case MTD_RAM:
		type = "ram";
		break;
	case MTD_ROM:
		type = "rom";
		break;
	case MTD_NORFLASH:
		type = "nor";
		break;
	case MTD_NANDFLASH:
		type = "nand";
		break;
	case MTD_DATAFLASH:
		type = "dataflash";
		break;
	case MTD_UBIVOLUME:
		type = "ubi";
		break;
	case MTD_MLCNANDFLASH:
		type = "mlc-nand";
		break;
	default:
		type = "unknown";
	}

	return snprintf(buf, PAGE_SIZE, "%s\n", type);
}
static DEVICE_ATTR(type, S_IRUGO, mtd_type_show, NULL);

static ssize_t mtd_flags_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)mtd->flags);

}
static DEVICE_ATTR(flags, S_IRUGO, mtd_flags_show, NULL);

static ssize_t mtd_size_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%llu\n",
		(unsigned long long)mtd->size);

}
static DEVICE_ATTR(size, S_IRUGO, mtd_size_show, NULL);

static ssize_t mtd_erasesize_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->erasesize);

}
static DEVICE_ATTR(erasesize, S_IRUGO, mtd_erasesize_show, NULL);

static ssize_t mtd_writesize_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->writesize);

}
static DEVICE_ATTR(writesize, S_IRUGO, mtd_writesize_show, NULL);

static ssize_t mtd_subpagesize_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);
	unsigned int subpagesize = mtd->writesize >> mtd->subpage_sft;

	return snprintf(buf, PAGE_SIZE, "%u\n", subpagesize);

}
static DEVICE_ATTR(subpagesize, S_IRUGO, mtd_subpagesize_show, NULL);

static ssize_t mtd_oobsize_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->oobsize);

}
static DEVICE_ATTR(oobsize, S_IRUGO, mtd_oobsize_show, NULL);

static ssize_t mtd_numeraseregions_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->numeraseregions);

}
static DEVICE_ATTR(numeraseregions, S_IRUGO, mtd_numeraseregions_show,
	NULL);

static ssize_t mtd_name_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%s\n", mtd->name);

}
static DEVICE_ATTR(name, S_IRUGO, mtd_name_show, NULL);

static ssize_t mtd_ecc_strength_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->ecc_strength);
}
static DEVICE_ATTR(ecc_strength, S_IRUGO, mtd_ecc_strength_show, NULL);

static ssize_t mtd_bitflip_threshold_show(struct device *dev,
					  struct device_attribute *attr,
					  char *buf)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->bitflip_threshold);
}

static ssize_t mtd_bitflip_threshold_store(struct device *dev,
					   struct device_attribute *attr,
					   const char *buf, size_t count)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);
	unsigned int bitflip_threshold;
	int retval;

	retval = kstrtouint(buf, 0, &bitflip_threshold);
	if (retval)
		return retval;

	mtd->bitflip_threshold = bitflip_threshold;
	return count;
}
static DEVICE_ATTR(bitflip_threshold, S_IRUGO | S_IWUSR,
		   mtd_bitflip_threshold_show,
		   mtd_bitflip_threshold_store);

static ssize_t mtd_ecc_step_size_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->ecc_step_size);

}
static DEVICE_ATTR(ecc_step_size, S_IRUGO, mtd_ecc_step_size_show, NULL);

static struct attribute *mtd_attrs[] = {
	&dev_attr_type.attr,
	&dev_attr_flags.attr,
	&dev_attr_size.attr,
	&dev_attr_erasesize.attr,
	&dev_attr_writesize.attr,
	&dev_attr_subpagesize.attr,
	&dev_attr_oobsize.attr,
	&dev_attr_numeraseregions.attr,
	&dev_attr_name.attr,
	&dev_attr_ecc_strength.attr,
	&dev_attr_ecc_step_size.attr,
	&dev_attr_bitflip_threshold.attr,
	NULL,
};
ATTRIBUTE_GROUPS(mtd);

static struct device_type mtd_devtype = {
	.name		= "mtd",
	.groups		= mtd_groups,
	.release	= mtd_release,
};
#endif

/**
 *	add_mtd_device - register an MTD device
 *	@mtd: pointer to new MTD device info structure
 *
 *	Add a device to the list of MTD devices present in the system, and
 *	notify each currently active MTD 'user' of its arrival. Returns
 *	zero on success or 1 on failure, which currently will only happen
 *	if there is insufficient memory or a sysfs error.
 */

int add_mtd_device(struct mtd_info *mtd)
{
#ifndef __UBOOT__
	struct mtd_notifier *not;
#endif
	int i, error;

#ifndef __UBOOT__
	if (!mtd->backing_dev_info) {
		switch (mtd->type) {
		case MTD_RAM:
			mtd->backing_dev_info = &mtd_bdi_rw_mappable;
			break;
		case MTD_ROM:
			mtd->backing_dev_info = &mtd_bdi_ro_mappable;
			break;
		default:
			mtd->backing_dev_info = &mtd_bdi_unmappable;
			break;
		}
	}
#endif

	BUG_ON(mtd->writesize == 0);
	mutex_lock(&mtd_table_mutex);

	i = idr_alloc(&mtd_idr, mtd, 0, 0, GFP_KERNEL);
	if (i < 0)
		goto fail_locked;

	mtd->index = i;
	mtd->usecount = 0;

	/* default value if not set by driver */
	if (mtd->bitflip_threshold == 0)
		mtd->bitflip_threshold = mtd->ecc_strength;

	if (is_power_of_2(mtd->erasesize))
		mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
	else
		mtd->erasesize_shift = 0;

	if (is_power_of_2(mtd->writesize))
		mtd->writesize_shift = ffs(mtd->writesize) - 1;
	else
		mtd->writesize_shift = 0;

	mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
	mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;

	/* Some chips always power up locked. Unlock them now */
	if ((mtd->flags & MTD_WRITEABLE) && (mtd->flags & MTD_POWERUP_LOCK)) {
		error = mtd_unlock(mtd, 0, mtd->size);
		if (error && error != -EOPNOTSUPP)
			printk(KERN_WARNING
			       "%s: unlock failed, writes may not work\n",
			       mtd->name);
	}

#ifndef __UBOOT__
	/* Caller should have set dev.parent to match the
	 * physical device.
	 */
	mtd->dev.type = &mtd_devtype;
	mtd->dev.class = &mtd_class;
	mtd->dev.devt = MTD_DEVT(i);
	dev_set_name(&mtd->dev, "mtd%d", i);
	dev_set_drvdata(&mtd->dev, mtd);
	if (device_register(&mtd->dev) != 0)
		goto fail_added;

	if (MTD_DEVT(i))
		device_create(&mtd_class, mtd->dev.parent,
			      MTD_DEVT(i) + 1,
			      NULL, "mtd%dro", i);

	pr_debug("mtd: Giving out device %d to %s\n", i, mtd->name);
	/* No need to get a refcount on the module containing
	   the notifier, since we hold the mtd_table_mutex */
	list_for_each_entry(not, &mtd_notifiers, list)
		not->add(mtd);
#else
	pr_debug("mtd: Giving out device %d to %s\n", i, mtd->name);
#endif

	mutex_unlock(&mtd_table_mutex);
	/* We _know_ we aren't being removed, because
	   our caller is still holding us here. So none
	   of this try_ nonsense, and no bitching about it
	   either. :) */
	__module_get(THIS_MODULE);
	return 0;

#ifndef __UBOOT__
fail_added:
	idr_remove(&mtd_idr, i);
#endif
fail_locked:
	mutex_unlock(&mtd_table_mutex);
	return 1;
}

/**
 *	del_mtd_device - unregister an MTD device
 *	@mtd: pointer to MTD device info structure
 *
 *	Remove a device from the list of MTD devices present in the system,
 *	and notify each currently active MTD 'user' of its departure.
 *	Returns zero on success or 1 on failure, which currently will happen
 *	if the requested device does not appear to be present in the list.
 */

int del_mtd_device(struct mtd_info *mtd)
{
	int ret;
#ifndef __UBOOT__
	struct mtd_notifier *not;
#endif

	mutex_lock(&mtd_table_mutex);

	if (idr_find(&mtd_idr, mtd->index) != mtd) {
		ret = -ENODEV;
		goto out_error;
	}

#ifndef __UBOOT__
	/* No need to get a refcount on the module containing
		the notifier, since we hold the mtd_table_mutex */
	list_for_each_entry(not, &mtd_notifiers, list)
		not->remove(mtd);
#endif

	if (mtd->usecount) {
		printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
		       mtd->index, mtd->name, mtd->usecount);
		ret = -EBUSY;
	} else {
#ifndef __UBOOT__
		device_unregister(&mtd->dev);
#endif

		idr_remove(&mtd_idr, mtd->index);

		module_put(THIS_MODULE);
		ret = 0;
	}

out_error:
	mutex_unlock(&mtd_table_mutex);
	return ret;
}

#ifndef __UBOOT__
/**
 * mtd_device_parse_register - parse partitions and register an MTD device.
 *
 * @mtd: the MTD device to register
 * @types: the list of MTD partition probes to try, see
 *         'parse_mtd_partitions()' for more information
 * @parser_data: MTD partition parser-specific data
 * @parts: fallback partition information to register, if parsing fails;
 *         only valid if %nr_parts > %0
 * @nr_parts: the number of partitions in parts, if zero then the full
 *            MTD device is registered if no partition info is found
 *
 * This function aggregates MTD partitions parsing (done by
 * 'parse_mtd_partitions()') and MTD device and partitions registering. It
 * basically follows the most common pattern found in many MTD drivers:
 *
 * * It first tries to probe partitions on MTD device @mtd using parsers
 *   specified in @types (if @types is %NULL, then the default list of parsers
 *   is used, see 'parse_mtd_partitions()' for more information). If none are
 *   found this functions tries to fallback to information specified in
 *   @parts/@nr_parts.
 * * If any partitioning info was found, this function registers the found
 *   partitions.
 * * If no partitions were found this function just registers the MTD device
 *   @mtd and exits.
 *
 * Returns zero in case of success and a negative error code in case of failure.
 */
int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types,
			      struct mtd_part_parser_data *parser_data,
			      const struct mtd_partition *parts,
			      int nr_parts)
{
	int err;
	struct mtd_partition *real_parts;

	err = parse_mtd_partitions(mtd, types, &real_parts, parser_data);
	if (err <= 0 && nr_parts && parts) {
		real_parts = kmemdup(parts, sizeof(*parts) * nr_parts,
				     GFP_KERNEL);
		if (!real_parts)
			err = -ENOMEM;
		else
			err = nr_parts;
	}

	if (err > 0) {
		err = add_mtd_partitions(mtd, real_parts, err);
		kfree(real_parts);
	} else if (err == 0) {
		err = add_mtd_device(mtd);
		if (err == 1)
			err = -ENODEV;
	}

	return err;
}
EXPORT_SYMBOL_GPL(mtd_device_parse_register);

/**
 * mtd_device_unregister - unregister an existing MTD device.
 *
 * @master: the MTD device to unregister.  This will unregister both the master
 *          and any partitions if registered.
 */
int mtd_device_unregister(struct mtd_info *master)
{
	int err;

	err = del_mtd_partitions(master);
	if (err)
		return err;

	if (!device_is_registered(&master->dev))
		return 0;

	return del_mtd_device(master);
}
EXPORT_SYMBOL_GPL(mtd_device_unregister);

/**
 *	register_mtd_user - register a 'user' of MTD devices.
 *	@new: pointer to notifier info structure
 *
 *	Registers a pair of callbacks function to be called upon addition
 *	or removal of MTD devices. Causes the 'add' callback to be immediately
 *	invoked for each MTD device currently present in the system.
 */
void register_mtd_user (struct mtd_notifier *new)
{
	struct mtd_info *mtd;

	mutex_lock(&mtd_table_mutex);

	list_add(&new->list, &mtd_notifiers);

	__module_get(THIS_MODULE);

	mtd_for_each_device(mtd)
		new->add(mtd);

	mutex_unlock(&mtd_table_mutex);
}
EXPORT_SYMBOL_GPL(register_mtd_user);

/**
 *	unregister_mtd_user - unregister a 'user' of MTD devices.
 *	@old: pointer to notifier info structure
 *
 *	Removes a callback function pair from the list of 'users' to be
 *	notified upon addition or removal of MTD devices. Causes the
 *	'remove' callback to be immediately invoked for each MTD device
 *	currently present in the system.
 */
int unregister_mtd_user (struct mtd_notifier *old)
{
	struct mtd_info *mtd;

	mutex_lock(&mtd_table_mutex);

	module_put(THIS_MODULE);

	mtd_for_each_device(mtd)
		old->remove(mtd);

	list_del(&old->list);
	mutex_unlock(&mtd_table_mutex);
	return 0;
}
EXPORT_SYMBOL_GPL(unregister_mtd_user);
#endif

/**
 *	get_mtd_device - obtain a validated handle for an MTD device
 *	@mtd: last known address of the required MTD device
 *	@num: internal device number of the required MTD device
 *
 *	Given a number and NULL address, return the num'th entry in the device
 *	table, if any.	Given an address and num == -1, search the device table
 *	for a device with that address and return if it's still present. Given
 *	both, return the num'th driver only if its address matches. Return
 *	error code if not.
 */
struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
{
	struct mtd_info *ret = NULL, *other;
	int err = -ENODEV;

	mutex_lock(&mtd_table_mutex);

	if (num == -1) {
		mtd_for_each_device(other) {
			if (other == mtd) {
				ret = mtd;
				break;
			}
		}
	} else if (num >= 0) {
		ret = idr_find(&mtd_idr, num);
		if (mtd && mtd != ret)
			ret = NULL;
	}

	if (!ret) {
		ret = ERR_PTR(err);
		goto out;
	}

	err = __get_mtd_device(ret);
	if (err)
		ret = ERR_PTR(err);
out:
	mutex_unlock(&mtd_table_mutex);
	return ret;
}
EXPORT_SYMBOL_GPL(get_mtd_device);


int __get_mtd_device(struct mtd_info *mtd)
{
	int err;

	if (!try_module_get(mtd->owner))
		return -ENODEV;

	if (mtd->_get_device) {
		err = mtd->_get_device(mtd);

		if (err) {
			module_put(mtd->owner);
			return err;
		}
	}
	mtd->usecount++;
	return 0;
}
EXPORT_SYMBOL_GPL(__get_mtd_device);

/**
 *	get_mtd_device_nm - obtain a validated handle for an MTD device by
 *	device name
 *	@name: MTD device name to open
 *
 * 	This function returns MTD device description structure in case of
 * 	success and an error code in case of failure.
 */
struct mtd_info *get_mtd_device_nm(const char *name)
{
	int err = -ENODEV;
	struct mtd_info *mtd = NULL, *other;

	mutex_lock(&mtd_table_mutex);

	mtd_for_each_device(other) {
		if (!strcmp(name, other->name)) {
			mtd = other;
			break;
		}
	}

	if (!mtd)
		goto out_unlock;

	err = __get_mtd_device(mtd);
	if (err)
		goto out_unlock;

	mutex_unlock(&mtd_table_mutex);
	return mtd;

out_unlock:
	mutex_unlock(&mtd_table_mutex);
	return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(get_mtd_device_nm);

#if defined(CONFIG_CMD_MTDPARTS_SPREAD)
/**
 * mtd_get_len_incl_bad
 *
 * Check if length including bad blocks fits into device.
 *
 * @param mtd an MTD device
 * @param offset offset in flash
 * @param length image length
 * @return image length including bad blocks in *len_incl_bad and whether or not
 *         the length returned was truncated in *truncated
 */
void mtd_get_len_incl_bad(struct mtd_info *mtd, uint64_t offset,
			  const uint64_t length, uint64_t *len_incl_bad,
			  int *truncated)
{
	*truncated = 0;
	*len_incl_bad = 0;

	if (!mtd->_block_isbad) {
		*len_incl_bad = length;
		return;
	}

	uint64_t len_excl_bad = 0;
	uint64_t block_len;

	while (len_excl_bad < length) {
		if (offset >= mtd->size) {
			*truncated = 1;
			return;
		}

		block_len = mtd->erasesize - (offset & (mtd->erasesize - 1));

		if (!mtd->_block_isbad(mtd, offset & ~(mtd->erasesize - 1)))
			len_excl_bad += block_len;

		*len_incl_bad += block_len;
		offset       += block_len;
	}
}
#endif /* defined(CONFIG_CMD_MTDPARTS_SPREAD) */

void put_mtd_device(struct mtd_info *mtd)
{
	mutex_lock(&mtd_table_mutex);
	__put_mtd_device(mtd);
	mutex_unlock(&mtd_table_mutex);

}
EXPORT_SYMBOL_GPL(put_mtd_device);

void __put_mtd_device(struct mtd_info *mtd)
{
	--mtd->usecount;
	BUG_ON(mtd->usecount < 0);

	if (mtd->_put_device)
		mtd->_put_device(mtd);

	module_put(mtd->owner);
}
EXPORT_SYMBOL_GPL(__put_mtd_device);

/*
 * Erase is an asynchronous operation.  Device drivers are supposed
 * to call instr->callback() whenever the operation completes, even
 * if it completes with a failure.
 * Callers are supposed to pass a callback function and wait for it
 * to be called before writing to the block.
 */
int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
{
	if (instr->addr > mtd->size || instr->len > mtd->size - instr->addr)
		return -EINVAL;
	if (!(mtd->flags & MTD_WRITEABLE))
		return -EROFS;
	instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
	if (!instr->len) {
		instr->state = MTD_ERASE_DONE;
		mtd_erase_callback(instr);
		return 0;
	}
	return mtd->_erase(mtd, instr);
}
EXPORT_SYMBOL_GPL(mtd_erase);

#ifndef __UBOOT__
/*
 * This stuff for eXecute-In-Place. phys is optional and may be set to NULL.
 */
int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
	      void **virt, resource_size_t *phys)
{
	*retlen = 0;
	*virt = NULL;
	if (phys)
		*phys = 0;
	if (!mtd->_point)
		return -EOPNOTSUPP;
	if (from < 0 || from > mtd->size || len > mtd->size - from)
		return -EINVAL;
	if (!len)
		return 0;
	return mtd->_point(mtd, from, len, retlen, virt, phys);
}
EXPORT_SYMBOL_GPL(mtd_point);

/* We probably shouldn't allow XIP if the unpoint isn't a NULL */
int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
{
	if (!mtd->_point)
		return -EOPNOTSUPP;
	if (from < 0 || from > mtd->size || len > mtd->size - from)
		return -EINVAL;
	if (!len)
		return 0;
	return mtd->_unpoint(mtd, from, len);
}
EXPORT_SYMBOL_GPL(mtd_unpoint);
#endif

/*
 * Allow NOMMU mmap() to directly map the device (if not NULL)
 * - return the address to which the offset maps
 * - return -ENOSYS to indicate refusal to do the mapping
 */
unsigned long mtd_get_unmapped_area(struct mtd_info *mtd, unsigned long len,
				    unsigned long offset, unsigned long flags)
{
	if (!mtd->_get_unmapped_area)
		return -EOPNOTSUPP;
	if (offset > mtd->size || len > mtd->size - offset)
		return -EINVAL;
	return mtd->_get_unmapped_area(mtd, len, offset, flags);
}
EXPORT_SYMBOL_GPL(mtd_get_unmapped_area);

int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
	     u_char *buf)
{
	int ret_code;
	*retlen = 0;
	if (from < 0 || from > mtd->size || len > mtd->size - from)
		return -EINVAL;
	if (!len)
		return 0;

	/*
	 * In the absence of an error, drivers return a non-negative integer
	 * representing the maximum number of bitflips that were corrected on
	 * any one ecc region (if applicable; zero otherwise).
	 */
	ret_code = mtd->_read(mtd, from, len, retlen, buf);
	if (unlikely(ret_code < 0))
		return ret_code;
	if (mtd->ecc_strength == 0)
		return 0;	/* device lacks ecc */
	return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
}
EXPORT_SYMBOL_GPL(mtd_read);

int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
	      const u_char *buf)
{
	*retlen = 0;
	if (to < 0 || to > mtd->size || len > mtd->size - to)
		return -EINVAL;
	if (!mtd->_write || !(mtd->flags & MTD_WRITEABLE))
		return -EROFS;
	if (!len)
		return 0;
	return mtd->_write(mtd, to, len, retlen, buf);
}
EXPORT_SYMBOL_GPL(mtd_write);

/*
 * In blackbox flight recorder like scenarios we want to make successful writes
 * in interrupt context. panic_write() is only intended to be called when its
 * known the kernel is about to panic and we need the write to succeed. Since
 * the kernel is not going to be running for much longer, this function can
 * break locks and delay to ensure the write succeeds (but not sleep).
 */
int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
		    const u_char *buf)
{
	*retlen = 0;
	if (!mtd->_panic_write)
		return -EOPNOTSUPP;
	if (to < 0 || to > mtd->size || len > mtd->size - to)
		return -EINVAL;
	if (!(mtd->flags & MTD_WRITEABLE))
		return -EROFS;
	if (!len)
		return 0;
	return mtd->_panic_write(mtd, to, len, retlen, buf);
}
EXPORT_SYMBOL_GPL(mtd_panic_write);

int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
{
	int ret_code;
	ops->retlen = ops->oobretlen = 0;
	if (!mtd->_read_oob)
		return -EOPNOTSUPP;
	/*
	 * In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics
	 * similar to mtd->_read(), returning a non-negative integer
	 * representing max bitflips. In other cases, mtd->_read_oob() may
	 * return -EUCLEAN. In all cases, perform similar logic to mtd_read().
	 */
	ret_code = mtd->_read_oob(mtd, from, ops);
	if (unlikely(ret_code < 0))
		return ret_code;
	if (mtd->ecc_strength == 0)
		return 0;	/* device lacks ecc */
	return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
}
EXPORT_SYMBOL_GPL(mtd_read_oob);

/**
 * mtd_ooblayout_ecc - Get the OOB region definition of a specific ECC section
 * @mtd: MTD device structure
 * @section: ECC section. Depending on the layout you may have all the ECC
 *	     bytes stored in a single contiguous section, or one section
 *	     per ECC chunk (and sometime several sections for a single ECC
 *	     ECC chunk)
 * @oobecc: OOB region struct filled with the appropriate ECC position
 *	    information
 *
 * This function returns ECC section information in the OOB area. If you want
 * to get all the ECC bytes information, then you should call
 * mtd_ooblayout_ecc(mtd, section++, oobecc) until it returns -ERANGE.
 *
 * Returns zero on success, a negative error code otherwise.
 */
int mtd_ooblayout_ecc(struct mtd_info *mtd, int section,
		      struct mtd_oob_region *oobecc)
{
	memset(oobecc, 0, sizeof(*oobecc));

	if (!mtd || section < 0)
		return -EINVAL;

	if (!mtd->ooblayout || !mtd->ooblayout->ecc)
		return -ENOTSUPP;

	return mtd->ooblayout->ecc(mtd, section, oobecc);
}
EXPORT_SYMBOL_GPL(mtd_ooblayout_ecc);

/**
 * mtd_ooblayout_free - Get the OOB region definition of a specific free
 *			section
 * @mtd: MTD device structure
 * @section: Free section you are interested in. Depending on the layout
 *	     you may have all the free bytes stored in a single contiguous
 *	     section, or one section per ECC chunk plus an extra section
 *	     for the remaining bytes (or other funky layout).
 * @oobfree: OOB region struct filled with the appropriate free position
 *	     information
 *
 * This function returns free bytes position in the OOB area. If you want
 * to get all the free bytes information, then you should call
 * mtd_ooblayout_free(mtd, section++, oobfree) until it returns -ERANGE.
 *
 * Returns zero on success, a negative error code otherwise.
 */
int mtd_ooblayout_free(struct mtd_info *mtd, int section,
		       struct mtd_oob_region *oobfree)
{
	memset(oobfree, 0, sizeof(*oobfree));

	if (!mtd || section < 0)
		return -EINVAL;

	if (!mtd->ooblayout || !mtd->ooblayout->free)
		return -ENOTSUPP;

	return mtd->ooblayout->free(mtd, section, oobfree);
}
EXPORT_SYMBOL_GPL(mtd_ooblayout_free);

/**
 * mtd_ooblayout_find_region - Find the region attached to a specific byte
 * @mtd: mtd info structure
 * @byte: the byte we are searching for
 * @sectionp: pointer where the section id will be stored
 * @oobregion: used to retrieve the ECC position
 * @iter: iterator function. Should be either mtd_ooblayout_free or
 *	  mtd_ooblayout_ecc depending on the region type you're searching for
 *
 * This function returns the section id and oobregion information of a
 * specific byte. For example, say you want to know where the 4th ECC byte is
 * stored, you'll use:
 *
 * mtd_ooblayout_find_region(mtd, 3, &section, &oobregion, mtd_ooblayout_ecc);
 *
 * Returns zero on success, a negative error code otherwise.
 */
static int mtd_ooblayout_find_region(struct mtd_info *mtd, int byte,
				int *sectionp, struct mtd_oob_region *oobregion,
				int (*iter)(struct mtd_info *,
					    int section,
					    struct mtd_oob_region *oobregion))
{
	int pos = 0, ret, section = 0;

	memset(oobregion, 0, sizeof(*oobregion));

	while (1) {
		ret = iter(mtd, section, oobregion);
		if (ret)
			return ret;

		if (pos + oobregion->length > byte)
			break;

		pos += oobregion->length;
		section++;
	}

	/*
	 * Adjust region info to make it start at the beginning at the
	 * 'start' ECC byte.
	 */
	oobregion->offset += byte - pos;
	oobregion->length -= byte - pos;
	*sectionp = section;

	return 0;
}

/**
 * mtd_ooblayout_find_eccregion - Find the ECC region attached to a specific
 *				  ECC byte
 * @mtd: mtd info structure
 * @eccbyte: the byte we are searching for
 * @sectionp: pointer where the section id will be stored
 * @oobregion: OOB region information
 *
 * Works like mtd_ooblayout_find_region() except it searches for a specific ECC
 * byte.
 *
 * Returns zero on success, a negative error code otherwise.
 */
int mtd_ooblayout_find_eccregion(struct mtd_info *mtd, int eccbyte,
				 int *section,
				 struct mtd_oob_region *oobregion)
{
	return mtd_ooblayout_find_region(mtd, eccbyte, section, oobregion,
					 mtd_ooblayout_ecc);
}
EXPORT_SYMBOL_GPL(mtd_ooblayout_find_eccregion);

/**
 * mtd_ooblayout_get_bytes - Extract OOB bytes from the oob buffer
 * @mtd: mtd info structure
 * @buf: destination buffer to store OOB bytes
 * @oobbuf: OOB buffer
 * @start: first byte to retrieve
 * @nbytes: number of bytes to retrieve
 * @iter: section iterator
 *
 * Extract bytes attached to a specific category (ECC or free)
 * from the OOB buffer and copy them into buf.
 *
 * Returns zero on success, a negative error code otherwise.
 */
static int mtd_ooblayout_get_bytes(struct mtd_info *mtd, u8 *buf,
				const u8 *oobbuf, int start, int nbytes,
				int (*iter)(struct mtd_info *,
					    int section,
					    struct mtd_oob_region *oobregion))
{
	struct mtd_oob_region oobregion;
	int section, ret;

	ret = mtd_ooblayout_find_region(mtd, start, &section,
					&oobregion, iter);

	while (!ret) {
		int cnt;

		cnt = min_t(int, nbytes, oobregion.length);
		memcpy(buf, oobbuf + oobregion.offset, cnt);
		buf += cnt;
		nbytes -= cnt;

		if (!nbytes)
			break;

		ret = iter(mtd, ++section, &oobregion);
	}

	return ret;
}

/**
 * mtd_ooblayout_set_bytes - put OOB bytes into the oob buffer
 * @mtd: mtd info structure
 * @buf: source buffer to get OOB bytes from
 * @oobbuf: OOB buffer
 * @start: first OOB byte to set
 * @nbytes: number of OOB bytes to set
 * @iter: section iterator
 *
 * Fill the OOB buffer with data provided in buf. The category (ECC or free)
 * is selected by passing the appropriate iterator.
 *
 * Returns zero on success, a negative error code otherwise.
 */
static int mtd_ooblayout_set_bytes(struct mtd_info *mtd, const u8 *buf,
				u8 *oobbuf, int start, int nbytes,
				int (*iter)(struct mtd_info *,
					    int section,
					    struct mtd_oob_region *oobregion))
{
	struct mtd_oob_region oobregion;
	int section, ret;

	ret = mtd_ooblayout_find_region(mtd, start, &section,
					&oobregion, iter);

	while (!ret) {
		int cnt;

		cnt = min_t(int, nbytes, oobregion.length);
		memcpy(oobbuf + oobregion.offset, buf, cnt);
		buf += cnt;
		nbytes -= cnt;

		if (!nbytes)
			break;

		ret = iter(mtd, ++section, &oobregion);
	}

	return ret;
}

/**
 * mtd_ooblayout_count_bytes - count the number of bytes in a OOB category
 * @mtd: mtd info structure
 * @iter: category iterator
 *
 * Count the number of bytes in a given category.
 *
 * Returns a positive value on success, a negative error code otherwise.
 */
static int mtd_ooblayout_count_bytes(struct mtd_info *mtd,
				int (*iter)(struct mtd_info *,
					    int section,
					    struct mtd_oob_region *oobregion))
{
	struct mtd_oob_region oobregion;
	int section = 0, ret, nbytes = 0;

	while (1) {
		ret = iter(mtd, section++, &oobregion);
		if (ret) {
			if (ret == -ERANGE)
				ret = nbytes;
			break;
		}

		nbytes += oobregion.length;
	}

	return ret;
}

/**
 * mtd_ooblayout_get_eccbytes - extract ECC bytes from the oob buffer
 * @mtd: mtd info structure
 * @eccbuf: destination buffer to store ECC bytes
 * @oobbuf: OOB buffer
 * @start: first ECC byte to retrieve
 * @nbytes: number of ECC bytes to retrieve
 *
 * Works like mtd_ooblayout_get_bytes(), except it acts on ECC bytes.
 *
 * Returns zero on success, a negative error code otherwise.
 */
int mtd_ooblayout_get_eccbytes(struct mtd_info *mtd, u8 *eccbuf,
			       const u8 *oobbuf, int start, int nbytes)
{
	return mtd_ooblayout_get_bytes(mtd, eccbuf, oobbuf, start, nbytes,
				       mtd_ooblayout_ecc);
}
EXPORT_SYMBOL_GPL(mtd_ooblayout_get_eccbytes);

/**
 * mtd_ooblayout_set_eccbytes - set ECC bytes into the oob buffer
 * @mtd: mtd info structure
 * @eccbuf: source buffer to get ECC bytes from
 * @oobbuf: OOB buffer
 * @start: first ECC byte to set
 * @nbytes: number of ECC bytes to set
 *
 * Works like mtd_ooblayout_set_bytes(), except it acts on ECC bytes.
 *
 * Returns zero on success, a negative error code otherwise.
 */
int mtd_ooblayout_set_eccbytes(struct mtd_info *mtd, const u8 *eccbuf,
			       u8 *oobbuf, int start, int nbytes)
{
	return mtd_ooblayout_set_bytes(mtd, eccbuf, oobbuf, start, nbytes,
				       mtd_ooblayout_ecc);
}
EXPORT_SYMBOL_GPL(mtd_ooblayout_set_eccbytes);

/**
 * mtd_ooblayout_get_databytes - extract data bytes from the oob buffer
 * @mtd: mtd info structure
 * @databuf: destination buffer to store ECC bytes
 * @oobbuf: OOB buffer
 * @start: first ECC byte to retrieve
 * @nbytes: number of ECC bytes to retrieve
 *
 * Works like mtd_ooblayout_get_bytes(), except it acts on free bytes.
 *
 * Returns zero on success, a negative error code otherwise.
 */
int mtd_ooblayout_get_databytes(struct mtd_info *mtd, u8 *databuf,
				const u8 *oobbuf, int start, int nbytes)
{
	return mtd_ooblayout_get_bytes(mtd, databuf, oobbuf, start, nbytes,
				       mtd_ooblayout_free);
}
EXPORT_SYMBOL_GPL(mtd_ooblayout_get_databytes);

/**
 * mtd_ooblayout_get_eccbytes - set data bytes into the oob buffer
 * @mtd: mtd info structure
 * @eccbuf: source buffer to get data bytes from
 * @oobbuf: OOB buffer
 * @start: first ECC byte to set
 * @nbytes: number of ECC bytes to set
 *
 * Works like mtd_ooblayout_get_bytes(), except it acts on free bytes.
 *
 * Returns zero on success, a negative error code otherwise.
 */
int mtd_ooblayout_set_databytes(struct mtd_info *mtd, const u8 *databuf,
				u8 *oobbuf, int start, int nbytes)
{
	return mtd_ooblayout_set_bytes(mtd, databuf, oobbuf, start, nbytes,
				       mtd_ooblayout_free);
}
EXPORT_SYMBOL_GPL(mtd_ooblayout_set_databytes);

/**
 * mtd_ooblayout_count_freebytes - count the number of free bytes in OOB
 * @mtd: mtd info structure
 *
 * Works like mtd_ooblayout_count_bytes(), except it count free bytes.
 *
 * Returns zero on success, a negative error code otherwise.
 */
int mtd_ooblayout_count_freebytes(struct mtd_info *mtd)
{
	return mtd_ooblayout_count_bytes(mtd, mtd_ooblayout_free);
}
EXPORT_SYMBOL_GPL(mtd_ooblayout_count_freebytes);

/**
 * mtd_ooblayout_count_freebytes - count the number of ECC bytes in OOB
 * @mtd: mtd info structure
 *
 * Works like mtd_ooblayout_count_bytes(), except it count ECC bytes.
 *
 * Returns zero on success, a negative error code otherwise.
 */
int mtd_ooblayout_count_eccbytes(struct mtd_info *mtd)
{
	return mtd_ooblayout_count_bytes(mtd, mtd_ooblayout_ecc);
}
EXPORT_SYMBOL_GPL(mtd_ooblayout_count_eccbytes);

/*
 * Method to access the protection register area, present in some flash
 * devices. The user data is one time programmable but the factory data is read
 * only.
 */
int mtd_get_fact_prot_info(struct mtd_info *mtd, size_t len, size_t *retlen,
			   struct otp_info *buf)
{
	if (!mtd->_get_fact_prot_info)
		return -EOPNOTSUPP;
	if (!len)
		return 0;
	return mtd->_get_fact_prot_info(mtd, len, retlen, buf);
}
EXPORT_SYMBOL_GPL(mtd_get_fact_prot_info);

int mtd_read_fact_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
			   size_t *retlen, u_char *buf)
{
	*retlen = 0;
	if (!mtd->_read_fact_prot_reg)
		return -EOPNOTSUPP;
	if (!len)
		return 0;
	return mtd->_read_fact_prot_reg(mtd, from, len, retlen, buf);
}
EXPORT_SYMBOL_GPL(mtd_read_fact_prot_reg);

int mtd_get_user_prot_info(struct mtd_info *mtd, size_t len, size_t *retlen,
			   struct otp_info *buf)
{
	if (!mtd->_get_user_prot_info)
		return -EOPNOTSUPP;
	if (!len)
		return 0;
	return mtd->_get_user_prot_info(mtd, len, retlen, buf);
}
EXPORT_SYMBOL_GPL(mtd_get_user_prot_info);

int mtd_read_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
			   size_t *retlen, u_char *buf)
{
	*retlen = 0;
	if (!mtd->_read_user_prot_reg)
		return -EOPNOTSUPP;
	if (!len)
		return 0;
	return mtd->_read_user_prot_reg(mtd, from, len, retlen, buf);
}
EXPORT_SYMBOL_GPL(mtd_read_user_prot_reg);

int mtd_write_user_prot_reg(struct mtd_info *mtd, loff_t to, size_t len,
			    size_t *retlen, u_char *buf)
{
	int ret;

	*retlen = 0;
	if (!mtd->_write_user_prot_reg)
		return -EOPNOTSUPP;
	if (!len)
		return 0;
	ret = mtd->_write_user_prot_reg(mtd, to, len, retlen, buf);
	if (ret)
		return ret;

	/*
	 * If no data could be written at all, we are out of memory and
	 * must return -ENOSPC.
	 */
	return (*retlen) ? 0 : -ENOSPC;
}
EXPORT_SYMBOL_GPL(mtd_write_user_prot_reg);

int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)
{
	if (!mtd->_lock_user_prot_reg)
		return -EOPNOTSUPP;
	if (!len)
		return 0;
	return mtd->_lock_user_prot_reg(mtd, from, len);
}
EXPORT_SYMBOL_GPL(mtd_lock_user_prot_reg);

/* Chip-supported device locking */
int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
	if (!mtd->_lock)
		return -EOPNOTSUPP;
	if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
		return -EINVAL;
	if (!len)
		return 0;
	return mtd->_lock(mtd, ofs, len);
}
EXPORT_SYMBOL_GPL(mtd_lock);

int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
	if (!mtd->_unlock)
		return -EOPNOTSUPP;
	if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
		return -EINVAL;
	if (!len)
		return 0;
	return mtd->_unlock(mtd, ofs, len);
}
EXPORT_SYMBOL_GPL(mtd_unlock);

int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
	if (!mtd->_is_locked)
		return -EOPNOTSUPP;
	if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
		return -EINVAL;
	if (!len)
		return 0;
	return mtd->_is_locked(mtd, ofs, len);
}
EXPORT_SYMBOL_GPL(mtd_is_locked);

int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs)
{
	if (ofs < 0 || ofs > mtd->size)
		return -EINVAL;
	if (!mtd->_block_isreserved)
		return 0;
	return mtd->_block_isreserved(mtd, ofs);
}
EXPORT_SYMBOL_GPL(mtd_block_isreserved);

int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
{
	if (ofs < 0 || ofs > mtd->size)
		return -EINVAL;
	if (!mtd->_block_isbad)
		return 0;
	return mtd->_block_isbad(mtd, ofs);
}
EXPORT_SYMBOL_GPL(mtd_block_isbad);

int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs)
{
	if (!mtd->_block_markbad)
		return -EOPNOTSUPP;
	if (ofs < 0 || ofs > mtd->size)
		return -EINVAL;
	if (!(mtd->flags & MTD_WRITEABLE))
		return -EROFS;
	return mtd->_block_markbad(mtd, ofs);
}
EXPORT_SYMBOL_GPL(mtd_block_markbad);

#ifndef __UBOOT__
/*
 * default_mtd_writev - the default writev method
 * @mtd: mtd device description object pointer
 * @vecs: the vectors to write
 * @count: count of vectors in @vecs
 * @to: the MTD device offset to write to
 * @retlen: on exit contains the count of bytes written to the MTD device.
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure.
 */
static int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
			      unsigned long count, loff_t to, size_t *retlen)
{
	unsigned long i;
	size_t totlen = 0, thislen;
	int ret = 0;

	for (i = 0; i < count; i++) {
		if (!vecs[i].iov_len)
			continue;
		ret = mtd_write(mtd, to, vecs[i].iov_len, &thislen,
				vecs[i].iov_base);
		totlen += thislen;
		if (ret || thislen != vecs[i].iov_len)
			break;
		to += vecs[i].iov_len;
	}
	*retlen = totlen;
	return ret;
}

/*
 * mtd_writev - the vector-based MTD write method
 * @mtd: mtd device description object pointer
 * @vecs: the vectors to write
 * @count: count of vectors in @vecs
 * @to: the MTD device offset to write to
 * @retlen: on exit contains the count of bytes written to the MTD device.
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure.
 */
int mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
	       unsigned long count, loff_t to, size_t *retlen)
{
	*retlen = 0;
	if (!(mtd->flags & MTD_WRITEABLE))
		return -EROFS;
	if (!mtd->_writev)
		return default_mtd_writev(mtd, vecs, count, to, retlen);
	return mtd->_writev(mtd, vecs, count, to, retlen);
}
EXPORT_SYMBOL_GPL(mtd_writev);

/**
 * mtd_kmalloc_up_to - allocate a contiguous buffer up to the specified size
 * @mtd: mtd device description object pointer
 * @size: a pointer to the ideal or maximum size of the allocation, points
 *        to the actual allocation size on success.
 *
 * This routine attempts to allocate a contiguous kernel buffer up to
 * the specified size, backing off the size of the request exponentially
 * until the request succeeds or until the allocation size falls below
 * the system page size. This attempts to make sure it does not adversely
 * impact system performance, so when allocating more than one page, we
 * ask the memory allocator to avoid re-trying, swapping, writing back
 * or performing I/O.
 *
 * Note, this function also makes sure that the allocated buffer is aligned to
 * the MTD device's min. I/O unit, i.e. the "mtd->writesize" value.
 *
 * This is called, for example by mtd_{read,write} and jffs2_scan_medium,
 * to handle smaller (i.e. degraded) buffer allocations under low- or
 * fragmented-memory situations where such reduced allocations, from a
 * requested ideal, are allowed.
 *
 * Returns a pointer to the allocated buffer on success; otherwise, NULL.
 */
void *mtd_kmalloc_up_to(const struct mtd_info *mtd, size_t *size)
{
	gfp_t flags = __GFP_NOWARN | __GFP_WAIT |
		       __GFP_NORETRY | __GFP_NO_KSWAPD;
	size_t min_alloc = max_t(size_t, mtd->writesize, PAGE_SIZE);
	void *kbuf;

	*size = min_t(size_t, *size, KMALLOC_MAX_SIZE);

	while (*size > min_alloc) {
		kbuf = kmalloc(*size, flags);
		if (kbuf)
			return kbuf;

		*size >>= 1;
		*size = ALIGN(*size, mtd->writesize);
	}

	/*
	 * For the last resort allocation allow 'kmalloc()' to do all sorts of
	 * things (write-back, dropping caches, etc) by using GFP_KERNEL.
	 */
	return kmalloc(*size, GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(mtd_kmalloc_up_to);
#endif

#ifdef CONFIG_PROC_FS

/*====================================================================*/
/* Support for /proc/mtd */

static int mtd_proc_show(struct seq_file *m, void *v)
{
	struct mtd_info *mtd;

	seq_puts(m, "dev:    size   erasesize  name\n");
	mutex_lock(&mtd_table_mutex);
	mtd_for_each_device(mtd) {
		seq_printf(m, "mtd%d: %8.8llx %8.8x \"%s\"\n",
			   mtd->index, (unsigned long long)mtd->size,
			   mtd->erasesize, mtd->name);
	}
	mutex_unlock(&mtd_table_mutex);
	return 0;
}

static int mtd_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, mtd_proc_show, NULL);
}

static const struct file_operations mtd_proc_ops = {
	.open		= mtd_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};
#endif /* CONFIG_PROC_FS */

/*====================================================================*/
/* Init code */

#ifndef __UBOOT__
static int __init mtd_bdi_init(struct backing_dev_info *bdi, const char *name)
{
	int ret;

	ret = bdi_init(bdi);
	if (!ret)
		ret = bdi_register(bdi, NULL, "%s", name);

	if (ret)
		bdi_destroy(bdi);

	return ret;
}

static struct proc_dir_entry *proc_mtd;

static int __init init_mtd(void)
{
	int ret;

	ret = class_register(&mtd_class);
	if (ret)
		goto err_reg;

	ret = mtd_bdi_init(&mtd_bdi_unmappable, "mtd-unmap");
	if (ret)
		goto err_bdi1;

	ret = mtd_bdi_init(&mtd_bdi_ro_mappable, "mtd-romap");
	if (ret)
		goto err_bdi2;

	ret = mtd_bdi_init(&mtd_bdi_rw_mappable, "mtd-rwmap");
	if (ret)
		goto err_bdi3;

	proc_mtd = proc_create("mtd", 0, NULL, &mtd_proc_ops);

	ret = init_mtdchar();
	if (ret)
		goto out_procfs;

	return 0;

out_procfs:
	if (proc_mtd)
		remove_proc_entry("mtd", NULL);
err_bdi3:
	bdi_destroy(&mtd_bdi_ro_mappable);
err_bdi2:
	bdi_destroy(&mtd_bdi_unmappable);
err_bdi1:
	class_unregister(&mtd_class);
err_reg:
	pr_err("Error registering mtd class or bdi: %d\n", ret);
	return ret;
}

static void __exit cleanup_mtd(void)
{
	cleanup_mtdchar();
	if (proc_mtd)
		remove_proc_entry("mtd", NULL);
	class_unregister(&mtd_class);
	bdi_destroy(&mtd_bdi_unmappable);
	bdi_destroy(&mtd_bdi_ro_mappable);
	bdi_destroy(&mtd_bdi_rw_mappable);
}

module_init(init_mtd);
module_exit(cleanup_mtd);
#endif

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
MODULE_DESCRIPTION("Core MTD registration and access routines");