aboutsummaryrefslogtreecommitdiff
path: root/drivers/mtd/devices/doc2000.c
blob: a4eb8b5b85ecb9b7db0c253622fc97720022f4f1 (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

/*
 * Linux driver for Disk-On-Chip 2000 and Millennium
 * (c) 1999 Machine Vision Holdings, Inc.
 * (c) 1999, 2000 David Woodhouse <dwmw2@infradead.org>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/errno.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/bitops.h>
#include <linux/mutex.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/doc2000.h>

#define DOC_SUPPORT_2000
#define DOC_SUPPORT_2000TSOP
#define DOC_SUPPORT_MILLENNIUM

#ifdef DOC_SUPPORT_2000
#define DoC_is_2000(doc) (doc->ChipID == DOC_ChipID_Doc2k)
#else
#define DoC_is_2000(doc) (0)
#endif

#if defined(DOC_SUPPORT_2000TSOP) || defined(DOC_SUPPORT_MILLENNIUM)
#define DoC_is_Millennium(doc) (doc->ChipID == DOC_ChipID_DocMil)
#else
#define DoC_is_Millennium(doc) (0)
#endif

/* #define ECC_DEBUG */

/* I have no idea why some DoC chips can not use memcpy_from|to_io().
 * This may be due to the different revisions of the ASIC controller built-in or
 * simplily a QA/Bug issue. Who knows ?? If you have trouble, please uncomment
 * this:
 #undef USE_MEMCPY
*/

static int doc_read(struct mtd_info *mtd, loff_t from, size_t len,
		    size_t *retlen, u_char *buf);
static int doc_write(struct mtd_info *mtd, loff_t to, size_t len,
		     size_t *retlen, const u_char *buf);
static int doc_read_oob(struct mtd_info *mtd, loff_t ofs,
			struct mtd_oob_ops *ops);
static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
			 struct mtd_oob_ops *ops);
static int doc_write_oob_nolock(struct mtd_info *mtd, loff_t ofs, size_t len,
			 size_t *retlen, const u_char *buf);
static int doc_erase (struct mtd_info *mtd, struct erase_info *instr);

static struct mtd_info *doc2klist = NULL;

/* Perform the required delay cycles by reading from the appropriate register */
static void DoC_Delay(struct DiskOnChip *doc, unsigned short cycles)
{
	volatile char dummy;
	int i;

	for (i = 0; i < cycles; i++) {
		if (DoC_is_Millennium(doc))
			dummy = ReadDOC(doc->virtadr, NOP);
		else
			dummy = ReadDOC(doc->virtadr, DOCStatus);
	}

}

/* DOC_WaitReady: Wait for RDY line to be asserted by the flash chip */
static int _DoC_WaitReady(struct DiskOnChip *doc)
{
	void __iomem *docptr = doc->virtadr;
	unsigned long timeo = jiffies + (HZ * 10);

	pr_debug("_DoC_WaitReady called for out-of-line wait\n");

	/* Out-of-line routine to wait for chip response */
	while (!(ReadDOC(docptr, CDSNControl) & CDSN_CTRL_FR_B)) {
		/* issue 2 read from NOP register after reading from CDSNControl register
	   	see Software Requirement 11.4 item 2. */
		DoC_Delay(doc, 2);

		if (time_after(jiffies, timeo)) {
			pr_debug("_DoC_WaitReady timed out.\n");
			return -EIO;
		}
		udelay(1);
		cond_resched();
	}

	return 0;
}

static inline int DoC_WaitReady(struct DiskOnChip *doc)
{
	void __iomem *docptr = doc->virtadr;

	/* This is inline, to optimise the common case, where it's ready instantly */
	int ret = 0;

	/* 4 read form NOP register should be issued in prior to the read from CDSNControl
	   see Software Requirement 11.4 item 2. */
	DoC_Delay(doc, 4);

	if (!(ReadDOC(docptr, CDSNControl) & CDSN_CTRL_FR_B))
		/* Call the out-of-line routine to wait */
		ret = _DoC_WaitReady(doc);

	/* issue 2 read from NOP register after reading from CDSNControl register
	   see Software Requirement 11.4 item 2. */
	DoC_Delay(doc, 2);

	return ret;
}

/* DoC_Command: Send a flash command to the flash chip through the CDSN Slow IO register to
   bypass the internal pipeline. Each of 4 delay cycles (read from the NOP register) is
   required after writing to CDSN Control register, see Software Requirement 11.4 item 3. */

static int DoC_Command(struct DiskOnChip *doc, unsigned char command,
			      unsigned char xtraflags)
{
	void __iomem *docptr = doc->virtadr;

	if (DoC_is_2000(doc))
		xtraflags |= CDSN_CTRL_FLASH_IO;

	/* Assert the CLE (Command Latch Enable) line to the flash chip */
	WriteDOC(xtraflags | CDSN_CTRL_CLE | CDSN_CTRL_CE, docptr, CDSNControl);
	DoC_Delay(doc, 4);	/* Software requirement 11.4.3 for Millennium */

	if (DoC_is_Millennium(doc))
		WriteDOC(command, docptr, CDSNSlowIO);

	/* Send the command */
	WriteDOC_(command, docptr, doc->ioreg);
	if (DoC_is_Millennium(doc))
		WriteDOC(command, docptr, WritePipeTerm);

	/* Lower the CLE line */
	WriteDOC(xtraflags | CDSN_CTRL_CE, docptr, CDSNControl);
	DoC_Delay(doc, 4);	/* Software requirement 11.4.3 for Millennium */

	/* Wait for the chip to respond - Software requirement 11.4.1 (extended for any command) */
	return DoC_WaitReady(doc);
}

/* DoC_Address: Set the current address for the flash chip through the CDSN Slow IO register to
   bypass the internal pipeline. Each of 4 delay cycles (read from the NOP register) is
   required after writing to CDSN Control register, see Software Requirement 11.4 item 3. */

static int DoC_Address(struct DiskOnChip *doc, int numbytes, unsigned long ofs,
		       unsigned char xtraflags1, unsigned char xtraflags2)
{
	int i;
	void __iomem *docptr = doc->virtadr;

	if (DoC_is_2000(doc))
		xtraflags1 |= CDSN_CTRL_FLASH_IO;

	/* Assert the ALE (Address Latch Enable) line to the flash chip */
	WriteDOC(xtraflags1 | CDSN_CTRL_ALE | CDSN_CTRL_CE, docptr, CDSNControl);

	DoC_Delay(doc, 4);	/* Software requirement 11.4.3 for Millennium */

	/* Send the address */
	/* Devices with 256-byte page are addressed as:
	   Column (bits 0-7), Page (bits 8-15, 16-23, 24-31)
	   * there is no device on the market with page256
	   and more than 24 bits.
	   Devices with 512-byte page are addressed as:
	   Column (bits 0-7), Page (bits 9-16, 17-24, 25-31)
	   * 25-31 is sent only if the chip support it.
	   * bit 8 changes the read command to be sent
	   (NAND_CMD_READ0 or NAND_CMD_READ1).
	 */

	if (numbytes == ADDR_COLUMN || numbytes == ADDR_COLUMN_PAGE) {
		if (DoC_is_Millennium(doc))
			WriteDOC(ofs & 0xff, docptr, CDSNSlowIO);
		WriteDOC_(ofs & 0xff, docptr, doc->ioreg);
	}

	if (doc->page256) {
		ofs = ofs >> 8;
	} else {
		ofs = ofs >> 9;
	}

	if (numbytes == ADDR_PAGE || numbytes == ADDR_COLUMN_PAGE) {
		for (i = 0; i < doc->pageadrlen; i++, ofs = ofs >> 8) {
			if (DoC_is_Millennium(doc))
				WriteDOC(ofs & 0xff, docptr, CDSNSlowIO);
			WriteDOC_(ofs & 0xff, docptr, doc->ioreg);
		}
	}

	if (DoC_is_Millennium(doc))
		WriteDOC(ofs & 0xff, docptr, WritePipeTerm);

	DoC_Delay(doc, 2);	/* Needed for some slow flash chips. mf. */

	/* FIXME: The SlowIO's for millennium could be replaced by
	   a single WritePipeTerm here. mf. */

	/* Lower the ALE line */
	WriteDOC(xtraflags1 | xtraflags2 | CDSN_CTRL_CE, docptr,
		 CDSNControl);

	DoC_Delay(doc, 4);	/* Software requirement 11.4.3 for Millennium */

	/* Wait for the chip to respond - Software requirement 11.4.1 */
	return DoC_WaitReady(doc);
}

/* Read a buffer from DoC, taking care of Millennium odditys */
static void DoC_ReadBuf(struct DiskOnChip *doc, u_char * buf, int len)
{
	volatile int dummy;
	int modulus = 0xffff;
	void __iomem *docptr = doc->virtadr;
	int i;

	if (len <= 0)
		return;

	if (DoC_is_Millennium(doc)) {
		/* Read the data via the internal pipeline through CDSN IO register,
		   see Pipelined Read Operations 11.3 */
		dummy = ReadDOC(docptr, ReadPipeInit);

		/* Millennium should use the LastDataRead register - Pipeline Reads */
		len--;

		/* This is needed for correctly ECC calculation */
		modulus = 0xff;
	}

	for (i = 0; i < len; i++)
		buf[i] = ReadDOC_(docptr, doc->ioreg + (i & modulus));

	if (DoC_is_Millennium(doc)) {
		buf[i] = ReadDOC(docptr, LastDataRead);
	}
}

/* Write a buffer to DoC, taking care of Millennium odditys */
static void DoC_WriteBuf(struct DiskOnChip *doc, const u_char * buf, int len)
{
	void __iomem *docptr = doc->virtadr;
	int i;

	if (len <= 0)
		return;

	for (i = 0; i < len; i++)
		WriteDOC_(buf[i], docptr, doc->ioreg + i);

	if (DoC_is_Millennium(doc)) {
		WriteDOC(0x00, docptr, WritePipeTerm);
	}
}


/* DoC_SelectChip: Select a given flash chip within the current floor */

static inline int DoC_SelectChip(struct DiskOnChip *doc, int chip)
{
	void __iomem *docptr = doc->virtadr;

	/* Software requirement 11.4.4 before writing DeviceSelect */
	/* Deassert the CE line to eliminate glitches on the FCE# outputs */
	WriteDOC(CDSN_CTRL_WP, docptr, CDSNControl);
	DoC_Delay(doc, 4);	/* Software requirement 11.4.3 for Millennium */

	/* Select the individual flash chip requested */
	WriteDOC(chip, docptr, CDSNDeviceSelect);
	DoC_Delay(doc, 4);

	/* Reassert the CE line */
	WriteDOC(CDSN_CTRL_CE | CDSN_CTRL_FLASH_IO | CDSN_CTRL_WP, docptr,
		 CDSNControl);
	DoC_Delay(doc, 4);	/* Software requirement 11.4.3 for Millennium */

	/* Wait for it to be ready */
	return DoC_WaitReady(doc);
}

/* DoC_SelectFloor: Select a given floor (bank of flash chips) */

static inline int DoC_SelectFloor(struct DiskOnChip *doc, int floor)
{
	void __iomem *docptr = doc->virtadr;

	/* Select the floor (bank) of chips required */
	WriteDOC(floor, docptr, FloorSelect);

	/* Wait for the chip to be ready */
	return DoC_WaitReady(doc);
}

/* DoC_IdentChip: Identify a given NAND chip given {floor,chip} */

static int DoC_IdentChip(struct DiskOnChip *doc, int floor, int chip)
{
	int mfr, id, i, j;
	volatile char dummy;

	/* Page in the required floor/chip */
	DoC_SelectFloor(doc, floor);
	DoC_SelectChip(doc, chip);

	/* Reset the chip */
	if (DoC_Command(doc, NAND_CMD_RESET, CDSN_CTRL_WP)) {
		pr_debug("DoC_Command (reset) for %d,%d returned true\n",
		      floor, chip);
		return 0;
	}


	/* Read the NAND chip ID: 1. Send ReadID command */
	if (DoC_Command(doc, NAND_CMD_READID, CDSN_CTRL_WP)) {
		pr_debug("DoC_Command (ReadID) for %d,%d returned true\n",
		      floor, chip);
		return 0;
	}

	/* Read the NAND chip ID: 2. Send address byte zero */
	DoC_Address(doc, ADDR_COLUMN, 0, CDSN_CTRL_WP, 0);

	/* Read the manufacturer and device id codes from the device */

	if (DoC_is_Millennium(doc)) {
		DoC_Delay(doc, 2);
		dummy = ReadDOC(doc->virtadr, ReadPipeInit);
		mfr = ReadDOC(doc->virtadr, LastDataRead);

		DoC_Delay(doc, 2);
		dummy = ReadDOC(doc->virtadr, ReadPipeInit);
		id = ReadDOC(doc->virtadr, LastDataRead);
	} else {
		/* CDSN Slow IO register see Software Req 11.4 item 5. */
		dummy = ReadDOC(doc->virtadr, CDSNSlowIO);
		DoC_Delay(doc, 2);
		mfr = ReadDOC_(doc->virtadr, doc->ioreg);

		/* CDSN Slow IO register see Software Req 11.4 item 5. */
		dummy = ReadDOC(doc->virtadr, CDSNSlowIO);
		DoC_Delay(doc, 2);
		id = ReadDOC_(doc->virtadr, doc->ioreg);
	}

	/* No response - return failure */
	if (mfr == 0xff || mfr == 0)
		return 0;

	/* Check it's the same as the first chip we identified.
	 * M-Systems say that any given DiskOnChip device should only
	 * contain _one_ type of flash part, although that's not a
	 * hardware restriction. */
	if (doc->mfr) {
		if (doc->mfr == mfr && doc->id == id)
			return 1;	/* This is the same as the first */
		else
			printk(KERN_WARNING
			       "Flash chip at floor %d, chip %d is different:\n",
			       floor, chip);
	}

	/* Print and store the manufacturer and ID codes. */
	for (i = 0; nand_flash_ids[i].name != NULL; i++) {
		if (id == nand_flash_ids[i].id) {
			/* Try to identify manufacturer */
			for (j = 0; nand_manuf_ids[j].id != 0x0; j++) {
				if (nand_manuf_ids[j].id == mfr)
					break;
			}
			printk(KERN_INFO
			       "Flash chip found: Manufacturer ID: %2.2X, "
			       "Chip ID: %2.2X (%s:%s)\n", mfr, id,
			       nand_manuf_ids[j].name, nand_flash_ids[i].name);
			if (!doc->mfr) {
				doc->mfr = mfr;
				doc->id = id;
				doc->chipshift =
					ffs((nand_flash_ids[i].chipsize << 20)) - 1;
				doc->page256 = (nand_flash_ids[i].pagesize == 256) ? 1 : 0;
				doc->pageadrlen = doc->chipshift > 25 ? 3 : 2;
				doc->erasesize =
				    nand_flash_ids[i].erasesize;
				return 1;
			}
			return 0;
		}
	}


	/* We haven't fully identified the chip. Print as much as we know. */
	printk(KERN_WARNING "Unknown flash chip found: %2.2X %2.2X\n",
	       id, mfr);

	printk(KERN_WARNING "Please report to dwmw2@infradead.org\n");
	return 0;
}

/* DoC_ScanChips: Find all NAND chips present in a DiskOnChip, and identify them */

static void DoC_ScanChips(struct DiskOnChip *this, int maxchips)
{
	int floor, chip;
	int numchips[MAX_FLOORS];
	int ret = 1;

	this->numchips = 0;
	this->mfr = 0;
	this->id = 0;

	/* For each floor, find the number of valid chips it contains */
	for (floor = 0; floor < MAX_FLOORS; floor++) {
		ret = 1;
		numchips[floor] = 0;
		for (chip = 0; chip < maxchips && ret != 0; chip++) {

			ret = DoC_IdentChip(this, floor, chip);
			if (ret) {
				numchips[floor]++;
				this->numchips++;
			}
		}
	}

	/* If there are none at all that we recognise, bail */
	if (!this->numchips) {
		printk(KERN_NOTICE "No flash chips recognised.\n");
		return;
	}

	/* Allocate an array to hold the information for each chip */
	this->chips = kmalloc(sizeof(struct Nand) * this->numchips, GFP_KERNEL);
	if (!this->chips) {
		printk(KERN_NOTICE "No memory for allocating chip info structures\n");
		return;
	}

	ret = 0;

	/* Fill out the chip array with {floor, chipno} for each
	 * detected chip in the device. */
	for (floor = 0; floor < MAX_FLOORS; floor++) {
		for (chip = 0; chip < numchips[floor]; chip++) {
			this->chips[ret].floor = floor;
			this->chips[ret].chip = chip;
			this->chips[ret].curadr = 0;
			this->chips[ret].curmode = 0x50;
			ret++;
		}
	}

	/* Calculate and print the total size of the device */
	this->totlen = this->numchips * (1 << this->chipshift);

	printk(KERN_INFO "%d flash chips found. Total DiskOnChip size: %ld MiB\n",
	       this->numchips, this->totlen >> 20);
}

static int DoC2k_is_alias(struct DiskOnChip *doc1, struct DiskOnChip *doc2)
{
	int tmp1, tmp2, retval;
	if (doc1->physadr == doc2->physadr)
		return 1;

	/* Use the alias resolution register which was set aside for this
	 * purpose. If it's value is the same on both chips, they might
	 * be the same chip, and we write to one and check for a change in
	 * the other. It's unclear if this register is usuable in the
	 * DoC 2000 (it's in the Millennium docs), but it seems to work. */
	tmp1 = ReadDOC(doc1->virtadr, AliasResolution);
	tmp2 = ReadDOC(doc2->virtadr, AliasResolution);
	if (tmp1 != tmp2)
		return 0;

	WriteDOC((tmp1 + 1) % 0xff, doc1->virtadr, AliasResolution);
	tmp2 = ReadDOC(doc2->virtadr, AliasResolution);
	if (tmp2 == (tmp1 + 1) % 0xff)
		retval = 1;
	else
		retval = 0;

	/* Restore register contents.  May not be necessary, but do it just to
	 * be safe. */
	WriteDOC(tmp1, doc1->virtadr, AliasResolution);

	return retval;
}

/* This routine is found from the docprobe code by symbol_get(),
 * which will bump the use count of this module. */
void DoC2k_init(struct mtd_info *mtd)
{
	struct DiskOnChip *this = mtd->priv;
	struct DiskOnChip *old = NULL;
	int maxchips;

	/* We must avoid being called twice for the same device. */

	if (doc2klist)
		old = doc2klist->priv;

	while (old) {
		if (DoC2k_is_alias(old, this)) {
			printk(KERN_NOTICE
			       "Ignoring DiskOnChip 2000 at 0x%lX - already configured\n",
			       this->physadr);
			iounmap(this->virtadr);
			kfree(mtd);
			return;
		}
		if (old->nextdoc)
			old = old->nextdoc->priv;
		else
			old = NULL;
	}


	switch (this->ChipID) {
	case DOC_ChipID_Doc2kTSOP:
		mtd->name = "DiskOnChip 2000 TSOP";
		this->ioreg = DoC_Mil_CDSN_IO;
		/* Pretend it's a Millennium */
		this->ChipID = DOC_ChipID_DocMil;
		maxchips = MAX_CHIPS;
		break;
	case DOC_ChipID_Doc2k:
		mtd->name = "DiskOnChip 2000";
		this->ioreg = DoC_2k_CDSN_IO;
		maxchips = MAX_CHIPS;
		break;
	case DOC_ChipID_DocMil:
		mtd->name = "DiskOnChip Millennium";
		this->ioreg = DoC_Mil_CDSN_IO;
		maxchips = MAX_CHIPS_MIL;
		break;
	default:
		printk("Unknown ChipID 0x%02x\n", this->ChipID);
		kfree(mtd);
		iounmap(this->virtadr);
		return;
	}

	printk(KERN_NOTICE "%s found at address 0x%lX\n", mtd->name,
	       this->physadr);

	mtd->type = MTD_NANDFLASH;
	mtd->flags = MTD_CAP_NANDFLASH;
	mtd->writebufsize = mtd->writesize = 512;
	mtd->oobsize = 16;
	mtd->ecc_strength = 2;
	mtd->owner = THIS_MODULE;
	mtd->_erase = doc_erase;
	mtd->_read = doc_read;
	mtd->_write = doc_write;
	mtd->_read_oob = doc_read_oob;
	mtd->_write_oob = doc_write_oob;
	this->curfloor = -1;
	this->curchip = -1;
	mutex_init(&this->lock);

	/* Ident all the chips present. */
	DoC_ScanChips(this, maxchips);

	if (!this->totlen) {
		kfree(mtd);
		iounmap(this->virtadr);
	} else {
		this->nextdoc = doc2klist;
		doc2klist = mtd;
		mtd->size = this->totlen;
		mtd->erasesize = this->erasesize;
		mtd_device_register(mtd, NULL, 0);
		return;
	}
}
EXPORT_SYMBOL_GPL(DoC2k_init);

static int doc_read(struct mtd_info *mtd, loff_t from, size_t len,
		    size_t * retlen, u_char * buf)
{
	struct DiskOnChip *this = mtd->priv;
	void __iomem *docptr = this->virtadr;
	struct Nand *mychip;
	unsigned char syndrome[6], eccbuf[6];
	volatile char dummy;
	int i, len256 = 0, ret=0;
	size_t left = len;

	mutex_lock(&this->lock);
	while (left) {
		len = left;

		/* Don't allow a single read to cross a 512-byte block boundary */
		if (from + len > ((from | 0x1ff) + 1))
			len = ((from | 0x1ff) + 1) - from;

		/* The ECC will not be calculated correctly if less than 512 is read */
		if (len != 0x200)
			printk(KERN_WARNING
			       "ECC needs a full sector read (adr: %lx size %lx)\n",
			       (long) from, (long) len);

		/* printk("DoC_Read (adr: %lx size %lx)\n", (long) from, (long) len); */


		/* Find the chip which is to be used and select it */
		mychip = &this->chips[from >> (this->chipshift)];

		if (this->curfloor != mychip->floor) {
			DoC_SelectFloor(this, mychip->floor);
			DoC_SelectChip(this, mychip->chip);
		} else if (this->curchip != mychip->chip) {
			DoC_SelectChip(this, mychip->chip);
		}

		this->curfloor = mychip->floor;
		this->curchip = mychip->chip;

		DoC_Command(this,
			    (!this->page256
			     && (from & 0x100)) ? NAND_CMD_READ1 : NAND_CMD_READ0,
			    CDSN_CTRL_WP);
		DoC_Address(this, ADDR_COLUMN_PAGE, from, CDSN_CTRL_WP,
			    CDSN_CTRL_ECC_IO);

		/* Prime the ECC engine */
		WriteDOC(DOC_ECC_RESET, docptr, ECCConf);
		WriteDOC(DOC_ECC_EN, docptr, ECCConf);

		/* treat crossing 256-byte sector for 2M x 8bits devices */
		if (this->page256 && from + len > (from | 0xff) + 1) {
			len256 = (from | 0xff) + 1 - from;
			DoC_ReadBuf(this, buf, len256);

			DoC_Command(this, NAND_CMD_READ0, CDSN_CTRL_WP);
			DoC_Address(this, ADDR_COLUMN_PAGE, from + len256,
				    CDSN_CTRL_WP, CDSN_CTRL_ECC_IO);
		}

		DoC_ReadBuf(this, &buf[len256], len - len256);

		/* Let the caller know we completed it */
		*retlen += len;

		/* Read the ECC data through the DiskOnChip ECC logic */
		/* Note: this will work even with 2M x 8bit devices as   */
		/*       they have 8 bytes of OOB per 256 page. mf.      */
		DoC_ReadBuf(this, eccbuf, 6);

		/* Flush the pipeline */
		if (DoC_is_Millennium(this)) {
			dummy = ReadDOC(docptr, ECCConf);
			dummy = ReadDOC(docptr, ECCConf);
			i = ReadDOC(docptr, ECCConf);
		} else {
			dummy = ReadDOC(docptr, 2k_ECCStatus);
			dummy = ReadDOC(docptr, 2k_ECCStatus);
			i = ReadDOC(docptr, 2k_ECCStatus);
		}

		/* Check the ECC Status */
		if (i & 0x80) {
			int nb_errors;
			/* There was an ECC error */
#ifdef ECC_DEBUG
			printk(KERN_ERR "DiskOnChip ECC Error: Read at %lx\n", (long)from);
#endif
			/* Read the ECC syndrome through the DiskOnChip ECC
			   logic.  These syndrome will be all ZERO when there
			   is no error */
			for (i = 0; i < 6; i++) {
				syndrome[i] =
					ReadDOC(docptr, ECCSyndrome0 + i);
			}
			nb_errors = doc_decode_ecc(buf, syndrome);

#ifdef ECC_DEBUG
			printk(KERN_ERR "Errors corrected: %x\n", nb_errors);
#endif
			if (nb_errors < 0) {
				/* We return error, but have actually done the
				   read. Not that this can be told to
				   user-space, via sys_read(), but at least
				   MTD-aware stuff can know about it by
				   checking *retlen */
				ret = -EIO;
			}
		}

#ifdef PSYCHO_DEBUG
		printk(KERN_DEBUG "ECC DATA at %lxB: %2.2X %2.2X %2.2X %2.2X %2.2X %2.2X\n",
		       (long)from, eccbuf[0], eccbuf[1], eccbuf[2],
		       eccbuf[3], eccbuf[4], eccbuf[5]);
#endif

		/* disable the ECC engine */
		WriteDOC(DOC_ECC_DIS, docptr , ECCConf);

		/* according to 11.4.1, we need to wait for the busy line
	         * drop if we read to the end of the page.  */
		if(0 == ((from + len) & 0x1ff))
		{
		    DoC_WaitReady(this);
		}

		from += len;
		left -= len;
		buf += len;
	}

	mutex_unlock(&this->lock);

	return ret;
}

static int doc_write(struct mtd_info *mtd, loff_t to, size_t len,
		     size_t * retlen, const u_char * buf)
{
	struct DiskOnChip *this = mtd->priv;
	int di; /* Yes, DI is a hangover from when I was disassembling the binary driver */
	void __iomem *docptr = this->virtadr;
	unsigned char eccbuf[6];
	volatile char dummy;
	int len256 = 0;
	struct Nand *mychip;
	size_t left = len;
	int status;

	mutex_lock(&this->lock);
	while (left) {
		len = left;

		/* Don't allow a single write to cross a 512-byte block boundary */
		if (to + len > ((to | 0x1ff) + 1))
			len = ((to | 0x1ff) + 1) - to;

		/* The ECC will not be calculated correctly if less than 512 is written */
/* DBB-
		if (len != 0x200 && eccbuf)
			printk(KERN_WARNING
			       "ECC needs a full sector write (adr: %lx size %lx)\n",
			       (long) to, (long) len);
   -DBB */

		/* printk("DoC_Write (adr: %lx size %lx)\n", (long) to, (long) len); */

		/* Find the chip which is to be used and select it */
		mychip = &this->chips[to >> (this->chipshift)];

		if (this->curfloor != mychip->floor) {
			DoC_SelectFloor(this, mychip->floor);
			DoC_SelectChip(this, mychip->chip);
		} else if (this->curchip != mychip->chip) {
			DoC_SelectChip(this, mychip->chip);
		}

		this->curfloor = mychip->floor;
		this->curchip = mychip->chip;

		/* Set device to main plane of flash */
		DoC_Command(this, NAND_CMD_RESET, CDSN_CTRL_WP);
		DoC_Command(this,
			    (!this->page256
			     && (to & 0x100)) ? NAND_CMD_READ1 : NAND_CMD_READ0,
			    CDSN_CTRL_WP);

		DoC_Command(this, NAND_CMD_SEQIN, 0);
		DoC_Address(this, ADDR_COLUMN_PAGE, to, 0, CDSN_CTRL_ECC_IO);

		/* Prime the ECC engine */
		WriteDOC(DOC_ECC_RESET, docptr, ECCConf);
		WriteDOC(DOC_ECC_EN | DOC_ECC_RW, docptr, ECCConf);

		/* treat crossing 256-byte sector for 2M x 8bits devices */
		if (this->page256 && to + len > (to | 0xff) + 1) {
			len256 = (to | 0xff) + 1 - to;
			DoC_WriteBuf(this, buf, len256);

			DoC_Command(this, NAND_CMD_PAGEPROG, 0);

			DoC_Command(this, NAND_CMD_STATUS, CDSN_CTRL_WP);
			/* There's an implicit DoC_WaitReady() in DoC_Command */

			dummy = ReadDOC(docptr, CDSNSlowIO);
			DoC_Delay(this, 2);

			if (ReadDOC_(docptr, this->ioreg) & 1) {
				printk(KERN_ERR "Error programming flash\n");
				/* Error in programming */
				*retlen = 0;
				mutex_unlock(&this->lock);
				return -EIO;
			}

			DoC_Command(this, NAND_CMD_SEQIN, 0);
			DoC_Address(this, ADDR_COLUMN_PAGE, to + len256, 0,
				    CDSN_CTRL_ECC_IO);
		}

		DoC_WriteBuf(this, &buf[len256], len - len256);

		WriteDOC(CDSN_CTRL_ECC_IO | CDSN_CTRL_CE, docptr, CDSNControl);

		if (DoC_is_Millennium(this)) {
			WriteDOC(0, docptr, NOP);
			WriteDOC(0, docptr, NOP);
			WriteDOC(0, docptr, NOP);
		} else {
			WriteDOC_(0, docptr, this->ioreg);
			WriteDOC_(0, docptr, this->ioreg);
			WriteDOC_(0, docptr, this->ioreg);
		}

		WriteDOC(CDSN_CTRL_ECC_IO | CDSN_CTRL_FLASH_IO | CDSN_CTRL_CE, docptr,
			 CDSNControl);

		/* Read the ECC data through the DiskOnChip ECC logic */
		for (di = 0; di < 6; di++) {
			eccbuf[di] = ReadDOC(docptr, ECCSyndrome0 + di);
		}

		/* Reset the ECC engine */
		WriteDOC(DOC_ECC_DIS, docptr, ECCConf);

#ifdef PSYCHO_DEBUG
		printk
			("OOB data at %lx is %2.2X %2.2X %2.2X %2.2X %2.2X %2.2X\n",
			 (long) to, eccbuf[0], eccbuf[1], eccbuf[2], eccbuf[3],
			 eccbuf[4], eccbuf[5]);
#endif
		DoC_Command(this, NAND_CMD_PAGEPROG, 0);

		DoC_Command(this, NAND_CMD_STATUS, CDSN_CTRL_WP);
		/* There's an implicit DoC_WaitReady() in DoC_Command */

		if (DoC_is_Millennium(this)) {
			ReadDOC(docptr, ReadPipeInit);
			status = ReadDOC(docptr, LastDataRead);
		} else {
			dummy = ReadDOC(docptr, CDSNSlowIO);
			DoC_Delay(this, 2);
			status = ReadDOC_(docptr, this->ioreg);
		}

		if (status & 1) {
			printk(KERN_ERR "Error programming flash\n");
			/* Error in programming */
			*retlen = 0;
			mutex_unlock(&this->lock);
			return -EIO;
		}

		/* Let the caller know we completed it */
		*retlen += len;

		{
			unsigned char x[8];
			size_t dummy;
			int ret;

			/* Write the ECC data to flash */
			for (di=0; di<6; di++)
				x[di] = eccbuf[di];

			x[6]=0x55;
			x[7]=0x55;

			ret = doc_write_oob_nolock(mtd, to, 8, &dummy, x);
			if (ret) {
				mutex_unlock(&this->lock);
				return ret;
			}
		}

		to += len;
		left -= len;
		buf += len;
	}

	mutex_unlock(&this->lock);
	return 0;
}

static int doc_read_oob(struct mtd_info *mtd, loff_t ofs,
			struct mtd_oob_ops *ops)
{
	struct DiskOnChip *this = mtd->priv;
	int len256 = 0, ret;
	struct Nand *mychip;
	uint8_t *buf = ops->oobbuf;
	size_t len = ops->len;

	BUG_ON(ops->mode != MTD_OPS_PLACE_OOB);

	ofs += ops->ooboffs;

	mutex_lock(&this->lock);

	mychip = &this->chips[ofs >> this->chipshift];

	if (this->curfloor != mychip->floor) {
		DoC_SelectFloor(this, mychip->floor);
		DoC_SelectChip(this, mychip->chip);
	} else if (this->curchip != mychip->chip) {
		DoC_SelectChip(this, mychip->chip);
	}
	this->curfloor = mychip->floor;
	this->curchip = mychip->chip;

	/* update address for 2M x 8bit devices. OOB starts on the second */
	/* page to maintain compatibility with doc_read_ecc. */
	if (this->page256) {
		if (!(ofs & 0x8))
			ofs += 0x100;
		else
			ofs -= 0x8;
	}

	DoC_Command(this, NAND_CMD_READOOB, CDSN_CTRL_WP);
	DoC_Address(this, ADDR_COLUMN_PAGE, ofs, CDSN_CTRL_WP, 0);

	/* treat crossing 8-byte OOB data for 2M x 8bit devices */
	/* Note: datasheet says it should automaticaly wrap to the */
	/*       next OOB block, but it didn't work here. mf.      */
	if (this->page256 && ofs + len > (ofs | 0x7) + 1) {
		len256 = (ofs | 0x7) + 1 - ofs;
		DoC_ReadBuf(this, buf, len256);

		DoC_Command(this, NAND_CMD_READOOB, CDSN_CTRL_WP);
		DoC_Address(this, ADDR_COLUMN_PAGE, ofs & (~0x1ff),
			    CDSN_CTRL_WP, 0);
	}

	DoC_ReadBuf(this, &buf[len256], len - len256);

	ops->retlen = len;
	/* Reading the full OOB data drops us off of the end of the page,
         * causing the flash device to go into busy mode, so we need
         * to wait until ready 11.4.1 and Toshiba TC58256FT docs */

	ret = DoC_WaitReady(this);

	mutex_unlock(&this->lock);
	return ret;

}

static int doc_write_oob_nolock(struct mtd_info *mtd, loff_t ofs, size_t len,
				size_t * retlen, const u_char * buf)
{
	struct DiskOnChip *this = mtd->priv;
	int len256 = 0;
	void __iomem *docptr = this->virtadr;
	struct Nand *mychip = &this->chips[ofs >> this->chipshift];
	volatile int dummy;
	int status;

	//      printk("doc_write_oob(%lx, %d): %2.2X %2.2X %2.2X %2.2X ... %2.2X %2.2X .. %2.2X %2.2X\n",(long)ofs, len,
	//   buf[0], buf[1], buf[2], buf[3], buf[8], buf[9], buf[14],buf[15]);

	/* Find the chip which is to be used and select it */
	if (this->curfloor != mychip->floor) {
		DoC_SelectFloor(this, mychip->floor);
		DoC_SelectChip(this, mychip->chip);
	} else if (this->curchip != mychip->chip) {
		DoC_SelectChip(this, mychip->chip);
	}
	this->curfloor = mychip->floor;
	this->curchip = mychip->chip;

	/* disable the ECC engine */
	WriteDOC (DOC_ECC_RESET, docptr, ECCConf);
	WriteDOC (DOC_ECC_DIS, docptr, ECCConf);

	/* Reset the chip, see Software Requirement 11.4 item 1. */
	DoC_Command(this, NAND_CMD_RESET, CDSN_CTRL_WP);

	/* issue the Read2 command to set the pointer to the Spare Data Area. */
	DoC_Command(this, NAND_CMD_READOOB, CDSN_CTRL_WP);

	/* update address for 2M x 8bit devices. OOB starts on the second */
	/* page to maintain compatibility with doc_read_ecc. */
	if (this->page256) {
		if (!(ofs & 0x8))
			ofs += 0x100;
		else
			ofs -= 0x8;
	}

	/* issue the Serial Data In command to initial the Page Program process */
	DoC_Command(this, NAND_CMD_SEQIN, 0);
	DoC_Address(this, ADDR_COLUMN_PAGE, ofs, 0, 0);

	/* treat crossing 8-byte OOB data for 2M x 8bit devices */
	/* Note: datasheet says it should automaticaly wrap to the */
	/*       next OOB block, but it didn't work here. mf.      */
	if (this->page256 && ofs + len > (ofs | 0x7) + 1) {
		len256 = (ofs | 0x7) + 1 - ofs;
		DoC_WriteBuf(this, buf, len256);

		DoC_Command(this, NAND_CMD_PAGEPROG, 0);
		DoC_Command(this, NAND_CMD_STATUS, 0);
		/* DoC_WaitReady() is implicit in DoC_Command */

		if (DoC_is_Millennium(this)) {
			ReadDOC(docptr, ReadPipeInit);
			status = ReadDOC(docptr, LastDataRead);
		} else {
			dummy = ReadDOC(docptr, CDSNSlowIO);
			DoC_Delay(this, 2);
			status = ReadDOC_(docptr, this->ioreg);
		}

		if (status & 1) {
			printk(KERN_ERR "Error programming oob data\n");
			/* There was an error */
			*retlen = 0;
			return -EIO;
		}
		DoC_Command(this, NAND_CMD_SEQIN, 0);
		DoC_Address(this, ADDR_COLUMN_PAGE, ofs & (~0x1ff), 0, 0);
	}

	DoC_WriteBuf(this, &buf[len256], len - len256);

	DoC_Command(this, NAND_CMD_PAGEPROG, 0);
	DoC_Command(this, NAND_CMD_STATUS, 0);
	/* DoC_WaitReady() is implicit in DoC_Command */

	if (DoC_is_Millennium(this)) {
		ReadDOC(docptr, ReadPipeInit);
		status = ReadDOC(docptr, LastDataRead);
	} else {
		dummy = ReadDOC(docptr, CDSNSlowIO);
		DoC_Delay(this, 2);
		status = ReadDOC_(docptr, this->ioreg);
	}

	if (status & 1) {
		printk(KERN_ERR "Error programming oob data\n");
		/* There was an error */
		*retlen = 0;
		return -EIO;
	}

	*retlen = len;
	return 0;

}

static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
			 struct mtd_oob_ops *ops)
{
	struct DiskOnChip *this = mtd->priv;
	int ret;

	BUG_ON(ops->mode != MTD_OPS_PLACE_OOB);

	mutex_lock(&this->lock);
	ret = doc_write_oob_nolock(mtd, ofs + ops->ooboffs, ops->len,
				   &ops->retlen, ops->oobbuf);

	mutex_unlock(&this->lock);
	return ret;
}

static int doc_erase(struct mtd_info *mtd, struct erase_info *instr)
{
	struct DiskOnChip *this = mtd->priv;
	__u32 ofs = instr->addr;
	__u32 len = instr->len;
	volatile int dummy;
	void __iomem *docptr = this->virtadr;
	struct Nand *mychip;
	int status;

 	mutex_lock(&this->lock);

	if (ofs & (mtd->erasesize-1) || len & (mtd->erasesize-1)) {
		mutex_unlock(&this->lock);
		return -EINVAL;
	}

	instr->state = MTD_ERASING;

	/* FIXME: Do this in the background. Use timers or schedule_task() */
	while(len) {
		mychip = &this->chips[ofs >> this->chipshift];

		if (this->curfloor != mychip->floor) {
			DoC_SelectFloor(this, mychip->floor);
			DoC_SelectChip(this, mychip->chip);
		} else if (this->curchip != mychip->chip) {
			DoC_SelectChip(this, mychip->chip);
		}
		this->curfloor = mychip->floor;
		this->curchip = mychip->chip;

		DoC_Command(this, NAND_CMD_ERASE1, 0);
		DoC_Address(this, ADDR_PAGE, ofs, 0, 0);
		DoC_Command(this, NAND_CMD_ERASE2, 0);

		DoC_Command(this, NAND_CMD_STATUS, CDSN_CTRL_WP);

		if (DoC_is_Millennium(this)) {
			ReadDOC(docptr, ReadPipeInit);
			status = ReadDOC(docptr, LastDataRead);
		} else {
			dummy = ReadDOC(docptr, CDSNSlowIO);
			DoC_Delay(this, 2);
			status = ReadDOC_(docptr, this->ioreg);
		}

		if (status & 1) {
			printk(KERN_ERR "Error erasing at 0x%x\n", ofs);
			/* There was an error */
			instr->state = MTD_ERASE_FAILED;
			goto callback;
		}
		ofs += mtd->erasesize;
		len -= mtd->erasesize;
	}
	instr->state = MTD_ERASE_DONE;

 callback:
	mtd_erase_callback(instr);

	mutex_unlock(&this->lock);
	return 0;
}


/****************************************************************************
 *
 * Module stuff
 *
 ****************************************************************************/

static void __exit cleanup_doc2000(void)
{
	struct mtd_info *mtd;
	struct DiskOnChip *this;

	while ((mtd = doc2klist)) {
		this = mtd->priv;
		doc2klist = this->nextdoc;

		mtd_device_unregister(mtd);

		iounmap(this->virtadr);
		kfree(this->chips);
		kfree(mtd);
	}
}

module_exit(cleanup_doc2000);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org> et al.");
MODULE_DESCRIPTION("MTD driver for DiskOnChip 2000 and Millennium");