aboutsummaryrefslogtreecommitdiff
path: root/drivers/mtd/sm_ftl.c
blob: 1c9f307ae0a177c6eca1aabf1bb68ed37ce0aa0e (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
/*
 * Copyright © 2009 - Maxim Levitsky
 * SmartMedia/xD translation layer
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/hdreg.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/sysfs.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/mtd/nand_ecc.h>
#include "nand/sm_common.h"
#include "sm_ftl.h"



struct workqueue_struct *cache_flush_workqueue;

static int cache_timeout = 1000;
module_param(cache_timeout, int, S_IRUGO);
MODULE_PARM_DESC(cache_timeout,
	"Timeout (in ms) for cache flush (1000 ms default");

static int debug;
module_param(debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug level (0-2)");


/* ------------------- sysfs attributes ---------------------------------- */
struct sm_sysfs_attribute {
	struct device_attribute dev_attr;
	char *data;
	int len;
};

ssize_t sm_attr_show(struct device *dev, struct device_attribute *attr,
		     char *buf)
{
	struct sm_sysfs_attribute *sm_attr =
		container_of(attr, struct sm_sysfs_attribute, dev_attr);

	strncpy(buf, sm_attr->data, sm_attr->len);
	return sm_attr->len;
}


#define NUM_ATTRIBUTES 1
#define SM_CIS_VENDOR_OFFSET 0x59
struct attribute_group *sm_create_sysfs_attributes(struct sm_ftl *ftl)
{
	struct attribute_group *attr_group;
	struct attribute **attributes;
	struct sm_sysfs_attribute *vendor_attribute;

	int vendor_len = strnlen(ftl->cis_buffer + SM_CIS_VENDOR_OFFSET,
					SM_SMALL_PAGE - SM_CIS_VENDOR_OFFSET);

	char *vendor = kmalloc(vendor_len, GFP_KERNEL);
	if (!vendor)
		goto error1;
	memcpy(vendor, ftl->cis_buffer + SM_CIS_VENDOR_OFFSET, vendor_len);
	vendor[vendor_len] = 0;

	/* Initialize sysfs attributes */
	vendor_attribute =
		kzalloc(sizeof(struct sm_sysfs_attribute), GFP_KERNEL);
	if (!vendor_attribute)
		goto error2;

	sysfs_attr_init(&vendor_attribute->dev_attr.attr);

	vendor_attribute->data = vendor;
	vendor_attribute->len = vendor_len;
	vendor_attribute->dev_attr.attr.name = "vendor";
	vendor_attribute->dev_attr.attr.mode = S_IRUGO;
	vendor_attribute->dev_attr.show = sm_attr_show;


	/* Create array of pointers to the attributes */
	attributes = kzalloc(sizeof(struct attribute *) * (NUM_ATTRIBUTES + 1),
								GFP_KERNEL);
	if (!attributes)
		goto error3;
	attributes[0] = &vendor_attribute->dev_attr.attr;

	/* Finally create the attribute group */
	attr_group = kzalloc(sizeof(struct attribute_group), GFP_KERNEL);
	if (!attr_group)
		goto error4;
	attr_group->attrs = attributes;
	return attr_group;
error4:
	kfree(attributes);
error3:
	kfree(vendor_attribute);
error2:
	kfree(vendor);
error1:
	return NULL;
}

void sm_delete_sysfs_attributes(struct sm_ftl *ftl)
{
	struct attribute **attributes = ftl->disk_attributes->attrs;
	int i;

	for (i = 0; attributes[i] ; i++) {

		struct device_attribute *dev_attr = container_of(attributes[i],
			struct device_attribute, attr);

		struct sm_sysfs_attribute *sm_attr =
			container_of(dev_attr,
				struct sm_sysfs_attribute, dev_attr);

		kfree(sm_attr->data);
		kfree(sm_attr);
	}

	kfree(ftl->disk_attributes->attrs);
	kfree(ftl->disk_attributes);
}


/* ----------------------- oob helpers -------------------------------------- */

static int sm_get_lba(uint8_t *lba)
{
	/* check fixed bits */
	if ((lba[0] & 0xF8) != 0x10)
		return -2;

	/* check parity - endianness doesn't matter */
	if (hweight16(*(uint16_t *)lba) & 1)
		return -2;

	return (lba[1] >> 1) | ((lba[0] & 0x07) << 7);
}


/*
 * Read LBA associated with block
 * returns -1, if block is erased
 * returns -2 if error happens
 */
static int sm_read_lba(struct sm_oob *oob)
{
	static const uint32_t erased_pattern[4] = {
		0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };

	uint16_t lba_test;
	int lba;

	/* First test for erased block */
	if (!memcmp(oob, erased_pattern, SM_OOB_SIZE))
		return -1;

	/* Now check is both copies of the LBA differ too much */
	lba_test = *(uint16_t *)oob->lba_copy1 ^ *(uint16_t*)oob->lba_copy2;
	if (lba_test && !is_power_of_2(lba_test))
		return -2;

	/* And read it */
	lba = sm_get_lba(oob->lba_copy1);

	if (lba == -2)
		lba = sm_get_lba(oob->lba_copy2);

	return lba;
}

static void sm_write_lba(struct sm_oob *oob, uint16_t lba)
{
	uint8_t tmp[2];

	WARN_ON(lba >= 1000);

	tmp[0] = 0x10 | ((lba >> 7) & 0x07);
	tmp[1] = (lba << 1) & 0xFF;

	if (hweight16(*(uint16_t *)tmp) & 0x01)
		tmp[1] |= 1;

	oob->lba_copy1[0] = oob->lba_copy2[0] = tmp[0];
	oob->lba_copy1[1] = oob->lba_copy2[1] = tmp[1];
}


/* Make offset from parts */
static loff_t sm_mkoffset(struct sm_ftl *ftl, int zone, int block, int boffset)
{
	WARN_ON(boffset & (SM_SECTOR_SIZE - 1));
	WARN_ON(zone < 0 || zone >= ftl->zone_count);
	WARN_ON(block >= ftl->zone_size);
	WARN_ON(boffset >= ftl->block_size);

	if (block == -1)
		return -1;

	return (zone * SM_MAX_ZONE_SIZE + block) * ftl->block_size + boffset;
}

/* Breaks offset into parts */
static void sm_break_offset(struct sm_ftl *ftl, loff_t offset,
			    int *zone, int *block, int *boffset)
{
	*boffset = do_div(offset, ftl->block_size);
	*block = do_div(offset, ftl->max_lba);
	*zone = offset >= ftl->zone_count ? -1 : offset;
}

/* ---------------------- low level IO ------------------------------------- */

static int sm_correct_sector(uint8_t *buffer, struct sm_oob *oob)
{
	uint8_t ecc[3];

	__nand_calculate_ecc(buffer, SM_SMALL_PAGE, ecc);
	if (__nand_correct_data(buffer, ecc, oob->ecc1, SM_SMALL_PAGE) < 0)
		return -EIO;

	buffer += SM_SMALL_PAGE;

	__nand_calculate_ecc(buffer, SM_SMALL_PAGE, ecc);
	if (__nand_correct_data(buffer, ecc, oob->ecc2, SM_SMALL_PAGE) < 0)
		return -EIO;
	return 0;
}

/* Reads a sector + oob*/
static int sm_read_sector(struct sm_ftl *ftl,
			  int zone, int block, int boffset,
			  uint8_t *buffer, struct sm_oob *oob)
{
	struct mtd_info *mtd = ftl->trans->mtd;
	struct mtd_oob_ops ops;
	struct sm_oob tmp_oob;
	int ret = -EIO;
	int try = 0;

	/* FTL can contain -1 entries that are by default filled with bits */
	if (block == -1) {
		memset(buffer, 0xFF, SM_SECTOR_SIZE);
		return 0;
	}

	/* User might not need the oob, but we do for data verification */
	if (!oob)
		oob = &tmp_oob;

	ops.mode = ftl->smallpagenand ? MTD_OPS_RAW : MTD_OPS_PLACE_OOB;
	ops.ooboffs = 0;
	ops.ooblen = SM_OOB_SIZE;
	ops.oobbuf = (void *)oob;
	ops.len = SM_SECTOR_SIZE;
	ops.datbuf = buffer;

again:
	if (try++) {
		/* Avoid infinite recursion on CIS reads, sm_recheck_media
			won't help anyway */
		if (zone == 0 && block == ftl->cis_block && boffset ==
			ftl->cis_boffset)
			return ret;

		/* Test if media is stable */
		if (try == 3 || sm_recheck_media(ftl))
			return ret;
	}

	/* Unfortunately, oob read will _always_ succeed,
		despite card removal..... */
	ret = mtd->read_oob(mtd, sm_mkoffset(ftl, zone, block, boffset), &ops);

	/* Test for unknown errors */
	if (ret != 0 && !mtd_is_bitflip_or_eccerr(ret)) {
		dbg("read of block %d at zone %d, failed due to error (%d)",
			block, zone, ret);
		goto again;
	}

	/* Do a basic test on the oob, to guard against returned garbage */
	if (oob->reserved != 0xFFFFFFFF && !is_power_of_2(~oob->reserved))
		goto again;

	/* This should never happen, unless there is a bug in the mtd driver */
	WARN_ON(ops.oobretlen != SM_OOB_SIZE);
	WARN_ON(buffer && ops.retlen != SM_SECTOR_SIZE);

	if (!buffer)
		return 0;

	/* Test if sector marked as bad */
	if (!sm_sector_valid(oob)) {
		dbg("read of block %d at zone %d, failed because it is marked"
			" as bad" , block, zone);
		goto again;
	}

	/* Test ECC*/
	if (mtd_is_eccerr(ret) ||
		(ftl->smallpagenand && sm_correct_sector(buffer, oob))) {

		dbg("read of block %d at zone %d, failed due to ECC error",
			block, zone);
		goto again;
	}

	return 0;
}

/* Writes a sector to media */
static int sm_write_sector(struct sm_ftl *ftl,
			   int zone, int block, int boffset,
			   uint8_t *buffer, struct sm_oob *oob)
{
	struct mtd_oob_ops ops;
	struct mtd_info *mtd = ftl->trans->mtd;
	int ret;

	BUG_ON(ftl->readonly);

	if (zone == 0 && (block == ftl->cis_block || block == 0)) {
		dbg("attempted to write the CIS!");
		return -EIO;
	}

	if (ftl->unstable)
		return -EIO;

	ops.mode = ftl->smallpagenand ? MTD_OPS_RAW : MTD_OPS_PLACE_OOB;
	ops.len = SM_SECTOR_SIZE;
	ops.datbuf = buffer;
	ops.ooboffs = 0;
	ops.ooblen = SM_OOB_SIZE;
	ops.oobbuf = (void *)oob;

	ret = mtd->write_oob(mtd, sm_mkoffset(ftl, zone, block, boffset), &ops);

	/* Now we assume that hardware will catch write bitflip errors */
	/* If you are paranoid, use CONFIG_MTD_NAND_VERIFY_WRITE */

	if (ret) {
		dbg("write to block %d at zone %d, failed with error %d",
			block, zone, ret);

		sm_recheck_media(ftl);
		return ret;
	}

	/* This should never happen, unless there is a bug in the driver */
	WARN_ON(ops.oobretlen != SM_OOB_SIZE);
	WARN_ON(buffer && ops.retlen != SM_SECTOR_SIZE);

	return 0;
}

/* ------------------------ block IO ------------------------------------- */

/* Write a block using data and lba, and invalid sector bitmap */
static int sm_write_block(struct sm_ftl *ftl, uint8_t *buf,
			  int zone, int block, int lba,
			  unsigned long invalid_bitmap)
{
	struct sm_oob oob;
	int boffset;
	int retry = 0;

	/* Initialize the oob with requested values */
	memset(&oob, 0xFF, SM_OOB_SIZE);
	sm_write_lba(&oob, lba);
restart:
	if (ftl->unstable)
		return -EIO;

	for (boffset = 0; boffset < ftl->block_size;
				boffset += SM_SECTOR_SIZE) {

		oob.data_status = 0xFF;

		if (test_bit(boffset / SM_SECTOR_SIZE, &invalid_bitmap)) {

			sm_printk("sector %d of block at LBA %d of zone %d"
				" coudn't be read, marking it as invalid",
				boffset / SM_SECTOR_SIZE, lba, zone);

			oob.data_status = 0;
		}

		if (ftl->smallpagenand) {
			__nand_calculate_ecc(buf + boffset,
						SM_SMALL_PAGE, oob.ecc1);

			__nand_calculate_ecc(buf + boffset + SM_SMALL_PAGE,
						SM_SMALL_PAGE, oob.ecc2);
		}
		if (!sm_write_sector(ftl, zone, block, boffset,
							buf + boffset, &oob))
			continue;

		if (!retry) {

			/* If write fails. try to erase the block */
			/* This is safe, because we never write in blocks
				that contain valuable data.
			This is intended to repair block that are marked
			as erased, but that isn't fully erased*/

			if (sm_erase_block(ftl, zone, block, 0))
				return -EIO;

			retry = 1;
			goto restart;
		} else {
			sm_mark_block_bad(ftl, zone, block);
			return -EIO;
		}
	}
	return 0;
}


/* Mark whole block at offset 'offs' as bad. */
static void sm_mark_block_bad(struct sm_ftl *ftl, int zone, int block)
{
	struct sm_oob oob;
	int boffset;

	memset(&oob, 0xFF, SM_OOB_SIZE);
	oob.block_status = 0xF0;

	if (ftl->unstable)
		return;

	if (sm_recheck_media(ftl))
		return;

	sm_printk("marking block %d of zone %d as bad", block, zone);

	/* We aren't checking the return value, because we don't care */
	/* This also fails on fake xD cards, but I guess these won't expose
		any bad blocks till fail completely */
	for (boffset = 0; boffset < ftl->block_size; boffset += SM_SECTOR_SIZE)
		sm_write_sector(ftl, zone, block, boffset, NULL, &oob);
}

/*
 * Erase a block within a zone
 * If erase succeeds, it updates free block fifo, otherwise marks block as bad
 */
static int sm_erase_block(struct sm_ftl *ftl, int zone_num, uint16_t block,
			  int put_free)
{
	struct ftl_zone *zone = &ftl->zones[zone_num];
	struct mtd_info *mtd = ftl->trans->mtd;
	struct erase_info erase;

	erase.mtd = mtd;
	erase.callback = sm_erase_callback;
	erase.addr = sm_mkoffset(ftl, zone_num, block, 0);
	erase.len = ftl->block_size;
	erase.priv = (u_long)ftl;

	if (ftl->unstable)
		return -EIO;

	BUG_ON(ftl->readonly);

	if (zone_num == 0 && (block == ftl->cis_block || block == 0)) {
		sm_printk("attempted to erase the CIS!");
		return -EIO;
	}

	if (mtd->erase(mtd, &erase)) {
		sm_printk("erase of block %d in zone %d failed",
							block, zone_num);
		goto error;
	}

	if (erase.state == MTD_ERASE_PENDING)
		wait_for_completion(&ftl->erase_completion);

	if (erase.state != MTD_ERASE_DONE) {
		sm_printk("erase of block %d in zone %d failed after wait",
			block, zone_num);
		goto error;
	}

	if (put_free)
		kfifo_in(&zone->free_sectors,
			(const unsigned char *)&block, sizeof(block));

	return 0;
error:
	sm_mark_block_bad(ftl, zone_num, block);
	return -EIO;
}

static void sm_erase_callback(struct erase_info *self)
{
	struct sm_ftl *ftl = (struct sm_ftl *)self->priv;
	complete(&ftl->erase_completion);
}

/* Thoroughly test that block is valid. */
static int sm_check_block(struct sm_ftl *ftl, int zone, int block)
{
	int boffset;
	struct sm_oob oob;
	int lbas[] = { -3, 0, 0, 0 };
	int i = 0;
	int test_lba;


	/* First just check that block doesn't look fishy */
	/* Only blocks that are valid or are sliced in two parts, are
		accepted */
	for (boffset = 0; boffset < ftl->block_size;
					boffset += SM_SECTOR_SIZE) {

		/* This shouldn't happen anyway */
		if (sm_read_sector(ftl, zone, block, boffset, NULL, &oob))
			return -2;

		test_lba = sm_read_lba(&oob);

		if (lbas[i] != test_lba)
			lbas[++i] = test_lba;

		/* If we found three different LBAs, something is fishy */
		if (i == 3)
			return -EIO;
	}

	/* If the block is sliced (partially erased usually) erase it */
	if (i == 2) {
		sm_erase_block(ftl, zone, block, 1);
		return 1;
	}

	return 0;
}

/* ----------------- media scanning --------------------------------- */
static const struct chs_entry chs_table[] = {
	{ 1,    125,  4,  4  },
	{ 2,    125,  4,  8  },
	{ 4,    250,  4,  8  },
	{ 8,    250,  4,  16 },
	{ 16,   500,  4,  16 },
	{ 32,   500,  8,  16 },
	{ 64,   500,  8,  32 },
	{ 128,  500,  16, 32 },
	{ 256,  1000, 16, 32 },
	{ 512,  1015, 32, 63 },
	{ 1024, 985,  33, 63 },
	{ 2048, 985,  33, 63 },
	{ 0 },
};


static const uint8_t cis_signature[] = {
	0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20
};
/* Find out media parameters.
 * This ideally has to be based on nand id, but for now device size is enough */
int sm_get_media_info(struct sm_ftl *ftl, struct mtd_info *mtd)
{
	int i;
	int size_in_megs = mtd->size / (1024 * 1024);

	ftl->readonly = mtd->type == MTD_ROM;

	/* Manual settings for very old devices */
	ftl->zone_count = 1;
	ftl->smallpagenand = 0;

	switch (size_in_megs) {
	case 1:
		/* 1 MiB flash/rom SmartMedia card (256 byte pages)*/
		ftl->zone_size = 256;
		ftl->max_lba = 250;
		ftl->block_size = 8 * SM_SECTOR_SIZE;
		ftl->smallpagenand = 1;

		break;
	case 2:
		/* 2 MiB flash SmartMedia (256 byte pages)*/
		if (mtd->writesize == SM_SMALL_PAGE) {
			ftl->zone_size = 512;
			ftl->max_lba = 500;
			ftl->block_size = 8 * SM_SECTOR_SIZE;
			ftl->smallpagenand = 1;
		/* 2 MiB rom SmartMedia */
		} else {

			if (!ftl->readonly)
				return -ENODEV;

			ftl->zone_size = 256;
			ftl->max_lba = 250;
			ftl->block_size = 16 * SM_SECTOR_SIZE;
		}
		break;
	case 4:
		/* 4 MiB flash/rom SmartMedia device */
		ftl->zone_size = 512;
		ftl->max_lba = 500;
		ftl->block_size = 16 * SM_SECTOR_SIZE;
		break;
	case 8:
		/* 8 MiB flash/rom SmartMedia device */
		ftl->zone_size = 1024;
		ftl->max_lba = 1000;
		ftl->block_size = 16 * SM_SECTOR_SIZE;
	}

	/* Minimum xD size is 16MiB. Also, all xD cards have standard zone
	   sizes. SmartMedia cards exist up to 128 MiB and have same layout*/
	if (size_in_megs >= 16) {
		ftl->zone_count = size_in_megs / 16;
		ftl->zone_size = 1024;
		ftl->max_lba = 1000;
		ftl->block_size = 32 * SM_SECTOR_SIZE;
	}

	/* Test for proper write,erase and oob sizes */
	if (mtd->erasesize > ftl->block_size)
		return -ENODEV;

	if (mtd->writesize > SM_SECTOR_SIZE)
		return -ENODEV;

	if (ftl->smallpagenand && mtd->oobsize < SM_SMALL_OOB_SIZE)
		return -ENODEV;

	if (!ftl->smallpagenand && mtd->oobsize < SM_OOB_SIZE)
		return -ENODEV;

	/* We use these functions for IO */
	if (!mtd->read_oob || !mtd->write_oob)
		return -ENODEV;

	/* Find geometry information */
	for (i = 0 ; i < ARRAY_SIZE(chs_table) ; i++) {
		if (chs_table[i].size == size_in_megs) {
			ftl->cylinders = chs_table[i].cyl;
			ftl->heads = chs_table[i].head;
			ftl->sectors = chs_table[i].sec;
			return 0;
		}
	}

	sm_printk("media has unknown size : %dMiB", size_in_megs);
	ftl->cylinders = 985;
	ftl->heads =  33;
	ftl->sectors = 63;
	return 0;
}

/* Validate the CIS */
static int sm_read_cis(struct sm_ftl *ftl)
{
	struct sm_oob oob;

	if (sm_read_sector(ftl,
		0, ftl->cis_block, ftl->cis_boffset, ftl->cis_buffer, &oob))
			return -EIO;

	if (!sm_sector_valid(&oob) || !sm_block_valid(&oob))
		return -EIO;

	if (!memcmp(ftl->cis_buffer + ftl->cis_page_offset,
			cis_signature, sizeof(cis_signature))) {
		return 0;
	}

	return -EIO;
}

/* Scan the media for the CIS */
static int sm_find_cis(struct sm_ftl *ftl)
{
	struct sm_oob oob;
	int block, boffset;
	int block_found = 0;
	int cis_found = 0;

	/* Search for first valid block */
	for (block = 0 ; block < ftl->zone_size - ftl->max_lba ; block++) {

		if (sm_read_sector(ftl, 0, block, 0, NULL, &oob))
			continue;

		if (!sm_block_valid(&oob))
			continue;
		block_found = 1;
		break;
	}

	if (!block_found)
		return -EIO;

	/* Search for first valid sector in this block */
	for (boffset = 0 ; boffset < ftl->block_size;
						boffset += SM_SECTOR_SIZE) {

		if (sm_read_sector(ftl, 0, block, boffset, NULL, &oob))
			continue;

		if (!sm_sector_valid(&oob))
			continue;
		break;
	}

	if (boffset == ftl->block_size)
		return -EIO;

	ftl->cis_block = block;
	ftl->cis_boffset = boffset;
	ftl->cis_page_offset = 0;

	cis_found = !sm_read_cis(ftl);

	if (!cis_found) {
		ftl->cis_page_offset = SM_SMALL_PAGE;
		cis_found = !sm_read_cis(ftl);
	}

	if (cis_found) {
		dbg("CIS block found at offset %x",
			block * ftl->block_size +
				boffset + ftl->cis_page_offset);
		return 0;
	}
	return -EIO;
}

/* Basic test to determine if underlying mtd device if functional */
static int sm_recheck_media(struct sm_ftl *ftl)
{
	if (sm_read_cis(ftl)) {

		if (!ftl->unstable) {
			sm_printk("media unstable, not allowing writes");
			ftl->unstable = 1;
		}
		return -EIO;
	}
	return 0;
}

/* Initialize a FTL zone */
static int sm_init_zone(struct sm_ftl *ftl, int zone_num)
{
	struct ftl_zone *zone = &ftl->zones[zone_num];
	struct sm_oob oob;
	uint16_t block;
	int lba;
	int i = 0;
	int len;

	dbg("initializing zone %d", zone_num);

	/* Allocate memory for FTL table */
	zone->lba_to_phys_table = kmalloc(ftl->max_lba * 2, GFP_KERNEL);

	if (!zone->lba_to_phys_table)
		return -ENOMEM;
	memset(zone->lba_to_phys_table, -1, ftl->max_lba * 2);


	/* Allocate memory for free sectors FIFO */
	if (kfifo_alloc(&zone->free_sectors, ftl->zone_size * 2, GFP_KERNEL)) {
		kfree(zone->lba_to_phys_table);
		return -ENOMEM;
	}

	/* Now scan the zone */
	for (block = 0 ; block < ftl->zone_size ; block++) {

		/* Skip blocks till the CIS (including) */
		if (zone_num == 0 && block <= ftl->cis_block)
			continue;

		/* Read the oob of first sector */
		if (sm_read_sector(ftl, zone_num, block, 0, NULL, &oob))
			return -EIO;

		/* Test to see if block is erased. It is enough to test
			first sector, because erase happens in one shot */
		if (sm_block_erased(&oob)) {
			kfifo_in(&zone->free_sectors,
				(unsigned char *)&block, 2);
			continue;
		}

		/* If block is marked as bad, skip it */
		/* This assumes we can trust first sector*/
		/* However the way the block valid status is defined, ensures
			very low probability of failure here */
		if (!sm_block_valid(&oob)) {
			dbg("PH %04d <-> <marked bad>", block);
			continue;
		}


		lba = sm_read_lba(&oob);

		/* Invalid LBA means that block is damaged. */
		/* We can try to erase it, or mark it as bad, but
			lets leave that to recovery application */
		if (lba == -2 || lba >= ftl->max_lba) {
			dbg("PH %04d <-> LBA %04d(bad)", block, lba);
			continue;
		}


		/* If there is no collision,
			just put the sector in the FTL table */
		if (zone->lba_to_phys_table[lba] < 0) {
			dbg_verbose("PH %04d <-> LBA %04d", block, lba);
			zone->lba_to_phys_table[lba] = block;
			continue;
		}

		sm_printk("collision"
			" of LBA %d between blocks %d and %d in zone %d",
			lba, zone->lba_to_phys_table[lba], block, zone_num);

		/* Test that this block is valid*/
		if (sm_check_block(ftl, zone_num, block))
			continue;

		/* Test now the old block */
		if (sm_check_block(ftl, zone_num,
					zone->lba_to_phys_table[lba])) {
			zone->lba_to_phys_table[lba] = block;
			continue;
		}

		/* If both blocks are valid and share same LBA, it means that
			they hold different versions of same data. It not
			known which is more recent, thus just erase one of them
		*/
		sm_printk("both blocks are valid, erasing the later");
		sm_erase_block(ftl, zone_num, block, 1);
	}

	dbg("zone initialized");
	zone->initialized = 1;

	/* No free sectors, means that the zone is heavily damaged, write won't
		work, but it can still can be (partially) read */
	if (!kfifo_len(&zone->free_sectors)) {
		sm_printk("no free blocks in zone %d", zone_num);
		return 0;
	}

	/* Randomize first block we write to */
	get_random_bytes(&i, 2);
	i %= (kfifo_len(&zone->free_sectors) / 2);

	while (i--) {
		len = kfifo_out(&zone->free_sectors,
					(unsigned char *)&block, 2);
		WARN_ON(len != 2);
		kfifo_in(&zone->free_sectors, (const unsigned char *)&block, 2);
	}
	return 0;
}

/* Get and automatically initialize an FTL mapping for one zone */
struct ftl_zone *sm_get_zone(struct sm_ftl *ftl, int zone_num)
{
	struct ftl_zone *zone;
	int error;

	BUG_ON(zone_num >= ftl->zone_count);
	zone = &ftl->zones[zone_num];

	if (!zone->initialized) {
		error = sm_init_zone(ftl, zone_num);

		if (error)
			return ERR_PTR(error);
	}
	return zone;
}


/* ----------------- cache handling ------------------------------------------*/

/* Initialize the one block cache */
void sm_cache_init(struct sm_ftl *ftl)
{
	ftl->cache_data_invalid_bitmap = 0xFFFFFFFF;
	ftl->cache_clean = 1;
	ftl->cache_zone = -1;
	ftl->cache_block = -1;
	/*memset(ftl->cache_data, 0xAA, ftl->block_size);*/
}

/* Put sector in one block cache */
void sm_cache_put(struct sm_ftl *ftl, char *buffer, int boffset)
{
	memcpy(ftl->cache_data + boffset, buffer, SM_SECTOR_SIZE);
	clear_bit(boffset / SM_SECTOR_SIZE, &ftl->cache_data_invalid_bitmap);
	ftl->cache_clean = 0;
}

/* Read a sector from the cache */
int sm_cache_get(struct sm_ftl *ftl, char *buffer, int boffset)
{
	if (test_bit(boffset / SM_SECTOR_SIZE,
		&ftl->cache_data_invalid_bitmap))
			return -1;

	memcpy(buffer, ftl->cache_data + boffset, SM_SECTOR_SIZE);
	return 0;
}

/* Write the cache to hardware */
int sm_cache_flush(struct sm_ftl *ftl)
{
	struct ftl_zone *zone;

	int sector_num;
	uint16_t write_sector;
	int zone_num = ftl->cache_zone;
	int block_num;

	if (ftl->cache_clean)
		return 0;

	if (ftl->unstable)
		return -EIO;

	BUG_ON(zone_num < 0);
	zone = &ftl->zones[zone_num];
	block_num = zone->lba_to_phys_table[ftl->cache_block];


	/* Try to read all unread areas of the cache block*/
	for_each_set_bit(sector_num, &ftl->cache_data_invalid_bitmap,
		ftl->block_size / SM_SECTOR_SIZE) {

		if (!sm_read_sector(ftl,
			zone_num, block_num, sector_num * SM_SECTOR_SIZE,
			ftl->cache_data + sector_num * SM_SECTOR_SIZE, NULL))
				clear_bit(sector_num,
					&ftl->cache_data_invalid_bitmap);
	}
restart:

	if (ftl->unstable)
		return -EIO;

	/* If there are no spare blocks, */
	/* we could still continue by erasing/writing the current block,
		but for such worn out media it doesn't worth the trouble,
			and the dangers */
	if (kfifo_out(&zone->free_sectors,
				(unsigned char *)&write_sector, 2) != 2) {
		dbg("no free sectors for write!");
		return -EIO;
	}


	if (sm_write_block(ftl, ftl->cache_data, zone_num, write_sector,
		ftl->cache_block, ftl->cache_data_invalid_bitmap))
			goto restart;

	/* Update the FTL table */
	zone->lba_to_phys_table[ftl->cache_block] = write_sector;

	/* Write succesfull, so erase and free the old block */
	if (block_num > 0)
		sm_erase_block(ftl, zone_num, block_num, 1);

	sm_cache_init(ftl);
	return 0;
}


/* flush timer, runs a second after last write */
static void sm_cache_flush_timer(unsigned long data)
{
	struct sm_ftl *ftl = (struct sm_ftl *)data;
	queue_work(cache_flush_workqueue, &ftl->flush_work);
}

/* cache flush work, kicked by timer */
static void sm_cache_flush_work(struct work_struct *work)
{
	struct sm_ftl *ftl = container_of(work, struct sm_ftl, flush_work);
	mutex_lock(&ftl->mutex);
	sm_cache_flush(ftl);
	mutex_unlock(&ftl->mutex);
	return;
}

/* ---------------- outside interface -------------------------------------- */

/* outside interface: read a sector */
static int sm_read(struct mtd_blktrans_dev *dev,
		   unsigned long sect_no, char *buf)
{
	struct sm_ftl *ftl = dev->priv;
	struct ftl_zone *zone;
	int error = 0, in_cache = 0;
	int zone_num, block, boffset;

	sm_break_offset(ftl, sect_no << 9, &zone_num, &block, &boffset);
	mutex_lock(&ftl->mutex);


	zone = sm_get_zone(ftl, zone_num);
	if (IS_ERR(zone)) {
		error = PTR_ERR(zone);
		goto unlock;
	}

	/* Have to look at cache first */
	if (ftl->cache_zone == zone_num && ftl->cache_block == block) {
		in_cache = 1;
		if (!sm_cache_get(ftl, buf, boffset))
			goto unlock;
	}

	/* Translate the block and return if doesn't exist in the table */
	block = zone->lba_to_phys_table[block];

	if (block == -1) {
		memset(buf, 0xFF, SM_SECTOR_SIZE);
		goto unlock;
	}

	if (sm_read_sector(ftl, zone_num, block, boffset, buf, NULL)) {
		error = -EIO;
		goto unlock;
	}

	if (in_cache)
		sm_cache_put(ftl, buf, boffset);
unlock:
	mutex_unlock(&ftl->mutex);
	return error;
}

/* outside interface: write a sector */
static int sm_write(struct mtd_blktrans_dev *dev,
				unsigned long sec_no, char *buf)
{
	struct sm_ftl *ftl = dev->priv;
	struct ftl_zone *zone;
	int error, zone_num, block, boffset;

	BUG_ON(ftl->readonly);
	sm_break_offset(ftl, sec_no << 9, &zone_num, &block, &boffset);

	/* No need in flush thread running now */
	del_timer(&ftl->timer);
	mutex_lock(&ftl->mutex);

	zone = sm_get_zone(ftl, zone_num);
	if (IS_ERR(zone)) {
		error = PTR_ERR(zone);
		goto unlock;
	}

	/* If entry is not in cache, flush it */
	if (ftl->cache_block != block || ftl->cache_zone != zone_num) {

		error = sm_cache_flush(ftl);
		if (error)
			goto unlock;

		ftl->cache_block = block;
		ftl->cache_zone = zone_num;
	}

	sm_cache_put(ftl, buf, boffset);
unlock:
	mod_timer(&ftl->timer, jiffies + msecs_to_jiffies(cache_timeout));
	mutex_unlock(&ftl->mutex);
	return error;
}

/* outside interface: flush everything */
static int sm_flush(struct mtd_blktrans_dev *dev)
{
	struct sm_ftl *ftl = dev->priv;
	int retval;

	mutex_lock(&ftl->mutex);
	retval =  sm_cache_flush(ftl);
	mutex_unlock(&ftl->mutex);
	return retval;
}

/* outside interface: device is released */
static int sm_release(struct mtd_blktrans_dev *dev)
{
	struct sm_ftl *ftl = dev->priv;

	mutex_lock(&ftl->mutex);
	del_timer_sync(&ftl->timer);
	cancel_work_sync(&ftl->flush_work);
	sm_cache_flush(ftl);
	mutex_unlock(&ftl->mutex);
	return 0;
}

/* outside interface: get geometry */
static int sm_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
{
	struct sm_ftl *ftl = dev->priv;
	geo->heads = ftl->heads;
	geo->sectors = ftl->sectors;
	geo->cylinders = ftl->cylinders;
	return 0;
}

/* external interface: main initialization function */
static void sm_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
{
	struct mtd_blktrans_dev *trans;
	struct sm_ftl *ftl;

	/* Allocate & initialize our private structure */
	ftl = kzalloc(sizeof(struct sm_ftl), GFP_KERNEL);
	if (!ftl)
		goto error1;


	mutex_init(&ftl->mutex);
	setup_timer(&ftl->timer, sm_cache_flush_timer, (unsigned long)ftl);
	INIT_WORK(&ftl->flush_work, sm_cache_flush_work);
	init_completion(&ftl->erase_completion);

	/* Read media information */
	if (sm_get_media_info(ftl, mtd)) {
		dbg("found unsupported mtd device, aborting");
		goto error2;
	}


	/* Allocate temporary CIS buffer for read retry support */
	ftl->cis_buffer = kzalloc(SM_SECTOR_SIZE, GFP_KERNEL);
	if (!ftl->cis_buffer)
		goto error2;

	/* Allocate zone array, it will be initialized on demand */
	ftl->zones = kzalloc(sizeof(struct ftl_zone) * ftl->zone_count,
								GFP_KERNEL);
	if (!ftl->zones)
		goto error3;

	/* Allocate the cache*/
	ftl->cache_data = kzalloc(ftl->block_size, GFP_KERNEL);

	if (!ftl->cache_data)
		goto error4;

	sm_cache_init(ftl);


	/* Allocate upper layer structure and initialize it */
	trans = kzalloc(sizeof(struct mtd_blktrans_dev), GFP_KERNEL);
	if (!trans)
		goto error5;

	ftl->trans = trans;
	trans->priv = ftl;

	trans->tr = tr;
	trans->mtd = mtd;
	trans->devnum = -1;
	trans->size = (ftl->block_size * ftl->max_lba * ftl->zone_count) >> 9;
	trans->readonly = ftl->readonly;

	if (sm_find_cis(ftl)) {
		dbg("CIS not found on mtd device, aborting");
		goto error6;
	}

	ftl->disk_attributes = sm_create_sysfs_attributes(ftl);
	if (!ftl->disk_attributes)
		goto error6;
	trans->disk_attributes = ftl->disk_attributes;

	sm_printk("Found %d MiB xD/SmartMedia FTL on mtd%d",
		(int)(mtd->size / (1024 * 1024)), mtd->index);

	dbg("FTL layout:");
	dbg("%d zone(s), each consists of %d blocks (+%d spares)",
		ftl->zone_count, ftl->max_lba,
		ftl->zone_size - ftl->max_lba);
	dbg("each block consists of %d bytes",
		ftl->block_size);


	/* Register device*/
	if (add_mtd_blktrans_dev(trans)) {
		dbg("error in mtdblktrans layer");
		goto error6;
	}
	return;
error6:
	kfree(trans);
error5:
	kfree(ftl->cache_data);
error4:
	kfree(ftl->zones);
error3:
	kfree(ftl->cis_buffer);
error2:
	kfree(ftl);
error1:
	return;
}

/* main interface: device {surprise,} removal */
static void sm_remove_dev(struct mtd_blktrans_dev *dev)
{
	struct sm_ftl *ftl = dev->priv;
	int i;

	del_mtd_blktrans_dev(dev);
	ftl->trans = NULL;

	for (i = 0 ; i < ftl->zone_count; i++) {

		if (!ftl->zones[i].initialized)
			continue;

		kfree(ftl->zones[i].lba_to_phys_table);
		kfifo_free(&ftl->zones[i].free_sectors);
	}

	sm_delete_sysfs_attributes(ftl);
	kfree(ftl->cis_buffer);
	kfree(ftl->zones);
	kfree(ftl->cache_data);
	kfree(ftl);
}

static struct mtd_blktrans_ops sm_ftl_ops = {
	.name		= "smblk",
	.major		= -1,
	.part_bits	= SM_FTL_PARTN_BITS,
	.blksize	= SM_SECTOR_SIZE,
	.getgeo		= sm_getgeo,

	.add_mtd	= sm_add_mtd,
	.remove_dev	= sm_remove_dev,

	.readsect	= sm_read,
	.writesect	= sm_write,

	.flush		= sm_flush,
	.release	= sm_release,

	.owner		= THIS_MODULE,
};

static __init int sm_module_init(void)
{
	int error = 0;
	cache_flush_workqueue = create_freezable_workqueue("smflush");

	if (IS_ERR(cache_flush_workqueue))
		return PTR_ERR(cache_flush_workqueue);

	error = register_mtd_blktrans(&sm_ftl_ops);
	if (error)
		destroy_workqueue(cache_flush_workqueue);
	return error;

}

static void __exit sm_module_exit(void)
{
	destroy_workqueue(cache_flush_workqueue);
	deregister_mtd_blktrans(&sm_ftl_ops);
}

module_init(sm_module_init);
module_exit(sm_module_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Maxim Levitsky <maximlevitsky@gmail.com>");
MODULE_DESCRIPTION("Smartmedia/xD mtd translation layer");