summaryrefslogtreecommitdiff
path: root/drivers/mtd/nand/davinci_nand.c
blob: fe3eba87de40687225658d2aea50f1760b15de1f (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
/*
 * davinci_nand.c - NAND Flash Driver for DaVinci family chips
 *
 * Copyright © 2006 Texas Instruments.
 *
 * Port to 2.6.23 Copyright © 2008 by:
 *   Sander Huijsen <Shuijsen@optelecom-nkf.com>
 *   Troy Kisky <troy.kisky@boundarydevices.com>
 *   Dirk Behme <Dirk.Behme@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/partitions.h>

#include <mach/nand.h>

#include <asm/mach-types.h>


/*
 * This is a device driver for the NAND flash controller found on the
 * various DaVinci family chips.  It handles up to four SoC chipselects,
 * and some flavors of secondary chipselect (e.g. based on A12) as used
 * with multichip packages.
 *
 * The 1-bit ECC hardware is supported, as well as the newer 4-bit ECC
 * available on chips like the DM355 and OMAP-L137 and needed with the
 * more error-prone MLC NAND chips.
 *
 * This driver assumes EM_WAIT connects all the NAND devices' RDY/nBUSY
 * outputs in a "wire-AND" configuration, with no per-chip signals.
 */
struct davinci_nand_info {
	struct mtd_info		mtd;
	struct nand_chip	chip;
	struct nand_ecclayout	ecclayout;

	struct device		*dev;
	struct clk		*clk;
	bool			partitioned;

	bool			is_readmode;

	void __iomem		*base;
	void __iomem		*vaddr;

	uint32_t		ioaddr;
	uint32_t		current_cs;

	uint32_t		mask_chipsel;
	uint32_t		mask_ale;
	uint32_t		mask_cle;

	uint32_t		core_chipsel;
};

static DEFINE_SPINLOCK(davinci_nand_lock);
static bool ecc4_busy;

#define to_davinci_nand(m) container_of(m, struct davinci_nand_info, mtd)


static inline unsigned int davinci_nand_readl(struct davinci_nand_info *info,
		int offset)
{
	return __raw_readl(info->base + offset);
}

static inline void davinci_nand_writel(struct davinci_nand_info *info,
		int offset, unsigned long value)
{
	__raw_writel(value, info->base + offset);
}

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

/*
 * Access to hardware control lines:  ALE, CLE, secondary chipselect.
 */

static void nand_davinci_hwcontrol(struct mtd_info *mtd, int cmd,
				   unsigned int ctrl)
{
	struct davinci_nand_info	*info = to_davinci_nand(mtd);
	uint32_t			addr = info->current_cs;
	struct nand_chip		*nand = mtd->priv;

	/* Did the control lines change? */
	if (ctrl & NAND_CTRL_CHANGE) {
		if ((ctrl & NAND_CTRL_CLE) == NAND_CTRL_CLE)
			addr |= info->mask_cle;
		else if ((ctrl & NAND_CTRL_ALE) == NAND_CTRL_ALE)
			addr |= info->mask_ale;

		nand->IO_ADDR_W = (void __iomem __force *)addr;
	}

	if (cmd != NAND_CMD_NONE)
		iowrite8(cmd, nand->IO_ADDR_W);
}

static void nand_davinci_select_chip(struct mtd_info *mtd, int chip)
{
	struct davinci_nand_info	*info = to_davinci_nand(mtd);
	uint32_t			addr = info->ioaddr;

	/* maybe kick in a second chipselect */
	if (chip > 0)
		addr |= info->mask_chipsel;
	info->current_cs = addr;

	info->chip.IO_ADDR_W = (void __iomem __force *)addr;
	info->chip.IO_ADDR_R = info->chip.IO_ADDR_W;
}

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

/*
 * 1-bit hardware ECC ... context maintained for each core chipselect
 */

static inline uint32_t nand_davinci_readecc_1bit(struct mtd_info *mtd)
{
	struct davinci_nand_info *info = to_davinci_nand(mtd);

	return davinci_nand_readl(info, NANDF1ECC_OFFSET
			+ 4 * info->core_chipsel);
}

static void nand_davinci_hwctl_1bit(struct mtd_info *mtd, int mode)
{
	struct davinci_nand_info *info;
	uint32_t nandcfr;
	unsigned long flags;

	info = to_davinci_nand(mtd);

	/* Reset ECC hardware */
	nand_davinci_readecc_1bit(mtd);

	spin_lock_irqsave(&davinci_nand_lock, flags);

	/* Restart ECC hardware */
	nandcfr = davinci_nand_readl(info, NANDFCR_OFFSET);
	nandcfr |= BIT(8 + info->core_chipsel);
	davinci_nand_writel(info, NANDFCR_OFFSET, nandcfr);

	spin_unlock_irqrestore(&davinci_nand_lock, flags);
}

/*
 * Read hardware ECC value and pack into three bytes
 */
static int nand_davinci_calculate_1bit(struct mtd_info *mtd,
				      const u_char *dat, u_char *ecc_code)
{
	unsigned int ecc_val = nand_davinci_readecc_1bit(mtd);
	unsigned int ecc24 = (ecc_val & 0x0fff) | ((ecc_val & 0x0fff0000) >> 4);

	/* invert so that erased block ecc is correct */
	ecc24 = ~ecc24;
	ecc_code[0] = (u_char)(ecc24);
	ecc_code[1] = (u_char)(ecc24 >> 8);
	ecc_code[2] = (u_char)(ecc24 >> 16);

	return 0;
}

static int nand_davinci_correct_1bit(struct mtd_info *mtd, u_char *dat,
				     u_char *read_ecc, u_char *calc_ecc)
{
	struct nand_chip *chip = mtd->priv;
	uint32_t eccNand = read_ecc[0] | (read_ecc[1] << 8) |
					  (read_ecc[2] << 16);
	uint32_t eccCalc = calc_ecc[0] | (calc_ecc[1] << 8) |
					  (calc_ecc[2] << 16);
	uint32_t diff = eccCalc ^ eccNand;

	if (diff) {
		if ((((diff >> 12) ^ diff) & 0xfff) == 0xfff) {
			/* Correctable error */
			if ((diff >> (12 + 3)) < chip->ecc.size) {
				dat[diff >> (12 + 3)] ^= BIT((diff >> 12) & 7);
				return 1;
			} else {
				return -1;
			}
		} else if (!(diff & (diff - 1))) {
			/* Single bit ECC error in the ECC itself,
			 * nothing to fix */
			return 1;
		} else {
			/* Uncorrectable error */
			return -1;
		}

	}
	return 0;
}

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

/*
 * 4-bit hardware ECC ... context maintained over entire AEMIF
 *
 * This is a syndrome engine, but we avoid NAND_ECC_HW_SYNDROME
 * since that forces use of a problematic "infix OOB" layout.
 * Among other things, it trashes manufacturer bad block markers.
 * Also, and specific to this hardware, it ECC-protects the "prepad"
 * in the OOB ... while having ECC protection for parts of OOB would
 * seem useful, the current MTD stack sometimes wants to update the
 * OOB without recomputing ECC.
 */

static void nand_davinci_hwctl_4bit(struct mtd_info *mtd, int mode)
{
	struct davinci_nand_info *info = to_davinci_nand(mtd);
	unsigned long flags;
	u32 val;

	spin_lock_irqsave(&davinci_nand_lock, flags);

	/* Start 4-bit ECC calculation for read/write */
	val = davinci_nand_readl(info, NANDFCR_OFFSET);
	val &= ~(0x03 << 4);
	val |= (info->core_chipsel << 4) | BIT(12);
	davinci_nand_writel(info, NANDFCR_OFFSET, val);

	info->is_readmode = (mode == NAND_ECC_READ);

	spin_unlock_irqrestore(&davinci_nand_lock, flags);
}

/* Read raw ECC code after writing to NAND. */
static void
nand_davinci_readecc_4bit(struct davinci_nand_info *info, u32 code[4])
{
	const u32 mask = 0x03ff03ff;

	code[0] = davinci_nand_readl(info, NAND_4BIT_ECC1_OFFSET) & mask;
	code[1] = davinci_nand_readl(info, NAND_4BIT_ECC2_OFFSET) & mask;
	code[2] = davinci_nand_readl(info, NAND_4BIT_ECC3_OFFSET) & mask;
	code[3] = davinci_nand_readl(info, NAND_4BIT_ECC4_OFFSET) & mask;
}

/* Terminate read ECC; or return ECC (as bytes) of data written to NAND. */
static int nand_davinci_calculate_4bit(struct mtd_info *mtd,
		const u_char *dat, u_char *ecc_code)
{
	struct davinci_nand_info *info = to_davinci_nand(mtd);
	u32 raw_ecc[4], *p;
	unsigned i;

	/* After a read, terminate ECC calculation by a dummy read
	 * of some 4-bit ECC register.  ECC covers everything that
	 * was read; correct() just uses the hardware state, so
	 * ecc_code is not needed.
	 */
	if (info->is_readmode) {
		davinci_nand_readl(info, NAND_4BIT_ECC1_OFFSET);
		return 0;
	}

	/* Pack eight raw 10-bit ecc values into ten bytes, making
	 * two passes which each convert four values (in upper and
	 * lower halves of two 32-bit words) into five bytes.  The
	 * ROM boot loader uses this same packing scheme.
	 */
	nand_davinci_readecc_4bit(info, raw_ecc);
	for (i = 0, p = raw_ecc; i < 2; i++, p += 2) {
		*ecc_code++ =   p[0]        & 0xff;
		*ecc_code++ = ((p[0] >>  8) & 0x03) | ((p[0] >> 14) & 0xfc);
		*ecc_code++ = ((p[0] >> 22) & 0x0f) | ((p[1] <<  4) & 0xf0);
		*ecc_code++ = ((p[1] >>  4) & 0x3f) | ((p[1] >> 10) & 0xc0);
		*ecc_code++ =  (p[1] >> 18) & 0xff;
	}

	return 0;
}

/* Correct up to 4 bits in data we just read, using state left in the
 * hardware plus the ecc_code computed when it was first written.
 */
static int nand_davinci_correct_4bit(struct mtd_info *mtd,
		u_char *data, u_char *ecc_code, u_char *null)
{
	int i;
	struct davinci_nand_info *info = to_davinci_nand(mtd);
	unsigned short ecc10[8];
	unsigned short *ecc16;
	u32 syndrome[4];
	unsigned num_errors, corrected;

	/* All bytes 0xff?  It's an erased page; ignore its ECC. */
	for (i = 0; i < 10; i++) {
		if (ecc_code[i] != 0xff)
			goto compare;
	}
	return 0;

compare:
	/* Unpack ten bytes into eight 10 bit values.  We know we're
	 * little-endian, and use type punning for less shifting/masking.
	 */
	if (WARN_ON(0x01 & (unsigned) ecc_code))
		return -EINVAL;
	ecc16 = (unsigned short *)ecc_code;

	ecc10[0] =  (ecc16[0] >>  0) & 0x3ff;
	ecc10[1] = ((ecc16[0] >> 10) & 0x3f) | ((ecc16[1] << 6) & 0x3c0);
	ecc10[2] =  (ecc16[1] >>  4) & 0x3ff;
	ecc10[3] = ((ecc16[1] >> 14) & 0x3)  | ((ecc16[2] << 2) & 0x3fc);
	ecc10[4] =  (ecc16[2] >>  8)         | ((ecc16[3] << 8) & 0x300);
	ecc10[5] =  (ecc16[3] >>  2) & 0x3ff;
	ecc10[6] = ((ecc16[3] >> 12) & 0xf)  | ((ecc16[4] << 4) & 0x3f0);
	ecc10[7] =  (ecc16[4] >>  6) & 0x3ff;

	/* Tell ECC controller about the expected ECC codes. */
	for (i = 7; i >= 0; i--)
		davinci_nand_writel(info, NAND_4BIT_ECC_LOAD_OFFSET, ecc10[i]);

	/* Allow time for syndrome calculation ... then read it.
	 * A syndrome of all zeroes 0 means no detected errors.
	 */
	davinci_nand_readl(info, NANDFSR_OFFSET);
	nand_davinci_readecc_4bit(info, syndrome);
	if (!(syndrome[0] | syndrome[1] | syndrome[2] | syndrome[3]))
		return 0;

	/*
	 * Clear any previous address calculation by doing a dummy read of an
	 * error address register.
	 */
	davinci_nand_readl(info, NAND_ERR_ADD1_OFFSET);

	/* Start address calculation, and wait for it to complete.
	 * We _could_ start reading more data while this is working,
	 * to speed up the overall page read.
	 */
	davinci_nand_writel(info, NANDFCR_OFFSET,
			davinci_nand_readl(info, NANDFCR_OFFSET) | BIT(13));
	for (;;) {
		u32	fsr = davinci_nand_readl(info, NANDFSR_OFFSET);

		switch ((fsr >> 8) & 0x0f) {
		case 0:		/* no error, should not happen */
			davinci_nand_readl(info, NAND_ERR_ERRVAL1_OFFSET);
			return 0;
		case 1:		/* five or more errors detected */
			davinci_nand_readl(info, NAND_ERR_ERRVAL1_OFFSET);
			return -EIO;
		case 2:		/* error addresses computed */
		case 3:
			num_errors = 1 + ((fsr >> 16) & 0x03);
			goto correct;
		default:	/* still working on it */
			cpu_relax();
			continue;
		}
	}

correct:
	/* correct each error */
	for (i = 0, corrected = 0; i < num_errors; i++) {
		int error_address, error_value;

		if (i > 1) {
			error_address = davinci_nand_readl(info,
						NAND_ERR_ADD2_OFFSET);
			error_value = davinci_nand_readl(info,
						NAND_ERR_ERRVAL2_OFFSET);
		} else {
			error_address = davinci_nand_readl(info,
						NAND_ERR_ADD1_OFFSET);
			error_value = davinci_nand_readl(info,
						NAND_ERR_ERRVAL1_OFFSET);
		}

		if (i & 1) {
			error_address >>= 16;
			error_value >>= 16;
		}
		error_address &= 0x3ff;
		error_address = (512 + 7) - error_address;

		if (error_address < 512) {
			data[error_address] ^= error_value;
			corrected++;
		}
	}

	return corrected;
}

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

/*
 * NOTE:  NAND boot requires ALE == EM_A[1], CLE == EM_A[2], so that's
 * how these chips are normally wired.  This translates to both 8 and 16
 * bit busses using ALE == BIT(3) in byte addresses, and CLE == BIT(4).
 *
 * For now we assume that configuration, or any other one which ignores
 * the two LSBs for NAND access ... so we can issue 32-bit reads/writes
 * and have that transparently morphed into multiple NAND operations.
 */
static void nand_davinci_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
{
	struct nand_chip *chip = mtd->priv;

	if ((0x03 & ((unsigned)buf)) == 0 && (0x03 & len) == 0)
		ioread32_rep(chip->IO_ADDR_R, buf, len >> 2);
	else if ((0x01 & ((unsigned)buf)) == 0 && (0x01 & len) == 0)
		ioread16_rep(chip->IO_ADDR_R, buf, len >> 1);
	else
		ioread8_rep(chip->IO_ADDR_R, buf, len);
}

static void nand_davinci_write_buf(struct mtd_info *mtd,
		const uint8_t *buf, int len)
{
	struct nand_chip *chip = mtd->priv;

	if ((0x03 & ((unsigned)buf)) == 0 && (0x03 & len) == 0)
		iowrite32_rep(chip->IO_ADDR_R, buf, len >> 2);
	else if ((0x01 & ((unsigned)buf)) == 0 && (0x01 & len) == 0)
		iowrite16_rep(chip->IO_ADDR_R, buf, len >> 1);
	else
		iowrite8_rep(chip->IO_ADDR_R, buf, len);
}

/*
 * Check hardware register for wait status. Returns 1 if device is ready,
 * 0 if it is still busy.
 */
static int nand_davinci_dev_ready(struct mtd_info *mtd)
{
	struct davinci_nand_info *info = to_davinci_nand(mtd);

	return davinci_nand_readl(info, NANDFSR_OFFSET) & BIT(0);
}

static void __init nand_dm6446evm_flash_init(struct davinci_nand_info *info)
{
	uint32_t regval, a1cr;

	/*
	 * NAND FLASH timings @ PLL1 == 459 MHz
	 *  - AEMIF.CLK freq   = PLL1/6 = 459/6 = 76.5 MHz
	 *  - AEMIF.CLK period = 1/76.5 MHz = 13.1 ns
	 */
	regval = 0
		| (0 << 31)           /* selectStrobe */
		| (0 << 30)           /* extWait (never with NAND) */
		| (1 << 26)           /* writeSetup      10 ns */
		| (3 << 20)           /* writeStrobe     40 ns */
		| (1 << 17)           /* writeHold       10 ns */
		| (0 << 13)           /* readSetup       10 ns */
		| (3 << 7)            /* readStrobe      60 ns */
		| (0 << 4)            /* readHold        10 ns */
		| (3 << 2)            /* turnAround      ?? ns */
		| (0 << 0)            /* asyncSize       8-bit bus */
		;
	a1cr = davinci_nand_readl(info, A1CR_OFFSET);
	if (a1cr != regval) {
		dev_dbg(info->dev, "Warning: NAND config: Set A1CR " \
		       "reg to 0x%08x, was 0x%08x, should be done by " \
		       "bootloader.\n", regval, a1cr);
		davinci_nand_writel(info, A1CR_OFFSET, regval);
	}
}

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

/* An ECC layout for using 4-bit ECC with small-page flash, storing
 * ten ECC bytes plus the manufacturer's bad block marker byte, and
 * and not overlapping the default BBT markers.
 */
static struct nand_ecclayout hwecc4_small __initconst = {
	.eccbytes = 10,
	.eccpos = { 0, 1, 2, 3, 4,
		/* offset 5 holds the badblock marker */
		6, 7,
		13, 14, 15, },
	.oobfree = {
		{.offset = 8, .length = 5, },
		{.offset = 16, },
	},
};

/* An ECC layout for using 4-bit ECC with large-page (2048bytes) flash,
 * storing ten ECC bytes plus the manufacturer's bad block marker byte,
 * and not overlapping the default BBT markers.
 */
static struct nand_ecclayout hwecc4_2048 __initconst = {
	.eccbytes = 40,
	.eccpos = {
		/* at the end of spare sector */
		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,
		},
	.oobfree = {
		/* 2 bytes at offset 0 hold manufacturer badblock markers */
		{.offset = 2, .length = 22, },
		/* 5 bytes at offset 8 hold BBT markers */
		/* 8 bytes at offset 16 hold JFFS2 clean markers */
	},
};

static int __init nand_davinci_probe(struct platform_device *pdev)
{
	struct davinci_nand_pdata	*pdata = pdev->dev.platform_data;
	struct davinci_nand_info	*info;
	struct resource			*res1;
	struct resource			*res2;
	void __iomem			*vaddr;
	void __iomem			*base;
	int				ret;
	uint32_t			val;
	nand_ecc_modes_t		ecc_mode;

	/* insist on board-specific configuration */
	if (!pdata)
		return -ENODEV;

	/* which external chipselect will we be managing? */
	if (pdev->id < 0 || pdev->id > 3)
		return -ENODEV;

	info = kzalloc(sizeof(*info), GFP_KERNEL);
	if (!info) {
		dev_err(&pdev->dev, "unable to allocate memory\n");
		ret = -ENOMEM;
		goto err_nomem;
	}

	platform_set_drvdata(pdev, info);

	res1 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	res2 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	if (!res1 || !res2) {
		dev_err(&pdev->dev, "resource missing\n");
		ret = -EINVAL;
		goto err_nomem;
	}

	vaddr = ioremap(res1->start, res1->end - res1->start);
	base = ioremap(res2->start, res2->end - res2->start);
	if (!vaddr || !base) {
		dev_err(&pdev->dev, "ioremap failed\n");
		ret = -EINVAL;
		goto err_ioremap;
	}

	info->dev		= &pdev->dev;
	info->base		= base;
	info->vaddr		= vaddr;

	info->mtd.priv		= &info->chip;
	info->mtd.name		= dev_name(&pdev->dev);
	info->mtd.owner		= THIS_MODULE;

	info->mtd.dev.parent	= &pdev->dev;

	info->chip.IO_ADDR_R	= vaddr;
	info->chip.IO_ADDR_W	= vaddr;
	info->chip.chip_delay	= 0;
	info->chip.select_chip	= nand_davinci_select_chip;

	/* options such as NAND_USE_FLASH_BBT or 16-bit widths */
	info->chip.options	= pdata->options;
	info->chip.bbt_td	= pdata->bbt_td;
	info->chip.bbt_md	= pdata->bbt_md;

	info->ioaddr		= (uint32_t __force) vaddr;

	info->current_cs	= info->ioaddr;
	info->core_chipsel	= pdev->id;
	info->mask_chipsel	= pdata->mask_chipsel;

	/* use nandboot-capable ALE/CLE masks by default */
	info->mask_ale		= pdata->mask_ale ? : MASK_ALE;
	info->mask_cle		= pdata->mask_cle ? : MASK_CLE;

	/* Set address of hardware control function */
	info->chip.cmd_ctrl	= nand_davinci_hwcontrol;
	info->chip.dev_ready	= nand_davinci_dev_ready;

	/* Speed up buffer I/O */
	info->chip.read_buf     = nand_davinci_read_buf;
	info->chip.write_buf    = nand_davinci_write_buf;

	/* Use board-specific ECC config */
	ecc_mode		= pdata->ecc_mode;

	ret = -EINVAL;
	switch (ecc_mode) {
	case NAND_ECC_NONE:
	case NAND_ECC_SOFT:
		pdata->ecc_bits = 0;
		break;
	case NAND_ECC_HW:
		if (pdata->ecc_bits == 4) {
			/* No sanity checks:  CPUs must support this,
			 * and the chips may not use NAND_BUSWIDTH_16.
			 */

			/* No sharing 4-bit hardware between chipselects yet */
			spin_lock_irq(&davinci_nand_lock);
			if (ecc4_busy)
				ret = -EBUSY;
			else
				ecc4_busy = true;
			spin_unlock_irq(&davinci_nand_lock);

			if (ret == -EBUSY)
				goto err_ecc;

			info->chip.ecc.calculate = nand_davinci_calculate_4bit;
			info->chip.ecc.correct = nand_davinci_correct_4bit;
			info->chip.ecc.hwctl = nand_davinci_hwctl_4bit;
			info->chip.ecc.bytes = 10;
		} else {
			info->chip.ecc.calculate = nand_davinci_calculate_1bit;
			info->chip.ecc.correct = nand_davinci_correct_1bit;
			info->chip.ecc.hwctl = nand_davinci_hwctl_1bit;
			info->chip.ecc.bytes = 3;
		}
		info->chip.ecc.size = 512;
		break;
	default:
		ret = -EINVAL;
		goto err_ecc;
	}
	info->chip.ecc.mode = ecc_mode;

	info->clk = clk_get(&pdev->dev, "aemif");
	if (IS_ERR(info->clk)) {
		ret = PTR_ERR(info->clk);
		dev_dbg(&pdev->dev, "unable to get AEMIF clock, err %d\n", ret);
		goto err_clk;
	}

	ret = clk_enable(info->clk);
	if (ret < 0) {
		dev_dbg(&pdev->dev, "unable to enable AEMIF clock, err %d\n",
			ret);
		goto err_clk_enable;
	}

	/* EMIF timings should normally be set by the boot loader,
	 * especially after boot-from-NAND.  The *only* reason to
	 * have this special casing for the DM6446 EVM is to work
	 * with boot-from-NOR ... with CS0 manually re-jumpered
	 * (after startup) so it addresses the NAND flash, not NOR.
	 * Even for dev boards, that's unusually rude...
	 */
	if (machine_is_davinci_evm())
		nand_dm6446evm_flash_init(info);

	spin_lock_irq(&davinci_nand_lock);

	/* put CSxNAND into NAND mode */
	val = davinci_nand_readl(info, NANDFCR_OFFSET);
	val |= BIT(info->core_chipsel);
	davinci_nand_writel(info, NANDFCR_OFFSET, val);

	spin_unlock_irq(&davinci_nand_lock);

	/* Scan to find existence of the device(s) */
	ret = nand_scan_ident(&info->mtd, pdata->mask_chipsel ? 2 : 1);
	if (ret < 0) {
		dev_dbg(&pdev->dev, "no NAND chip(s) found\n");
		goto err_scan;
	}

	/* Update ECC layout if needed ... for 1-bit HW ECC, the default
	 * is OK, but it allocates 6 bytes when only 3 are needed (for
	 * each 512 bytes).  For the 4-bit HW ECC, that default is not
	 * usable:  10 bytes are needed, not 6.
	 */
	if (pdata->ecc_bits == 4) {
		int	chunks = info->mtd.writesize / 512;

		if (!chunks || info->mtd.oobsize < 16) {
			dev_dbg(&pdev->dev, "too small\n");
			ret = -EINVAL;
			goto err_scan;
		}

		/* For small page chips, preserve the manufacturer's
		 * badblock marking data ... and make sure a flash BBT
		 * table marker fits in the free bytes.
		 */
		if (chunks == 1) {
			info->ecclayout = hwecc4_small;
			info->ecclayout.oobfree[1].length =
				info->mtd.oobsize - 16;
			goto syndrome_done;
		}
		if (chunks == 4) {
			info->ecclayout = hwecc4_2048;
			info->chip.ecc.mode = NAND_ECC_HW_OOB_FIRST;
			goto syndrome_done;
		}

		/* 4KiB page chips are not yet supported. The eccpos from
		 * nand_ecclayout cannot hold 80 bytes and change to eccpos[]
		 * breaks userspace ioctl interface with mtd-utils. Once we
		 * resolve this issue, NAND_ECC_HW_OOB_FIRST mode can be used
		 * for the 4KiB page chips.
		 */
		dev_warn(&pdev->dev, "no 4-bit ECC support yet "
				"for 4KiB-page NAND\n");
		ret = -EIO;
		goto err_scan;

syndrome_done:
		info->chip.ecc.layout = &info->ecclayout;
	}

	ret = nand_scan_tail(&info->mtd);
	if (ret < 0)
		goto err_scan;

	if (mtd_has_partitions()) {
		struct mtd_partition	*mtd_parts = NULL;
		int			mtd_parts_nb = 0;

		if (mtd_has_cmdlinepart()) {
			static const char *probes[] __initconst =
				{ "cmdlinepart", NULL };

			mtd_parts_nb = parse_mtd_partitions(&info->mtd, probes,
							    &mtd_parts, 0);
		}

		if (mtd_parts_nb <= 0) {
			mtd_parts = pdata->parts;
			mtd_parts_nb = pdata->nr_parts;
		}

		/* Register any partitions */
		if (mtd_parts_nb > 0) {
			ret = add_mtd_partitions(&info->mtd,
					mtd_parts, mtd_parts_nb);
			if (ret == 0)
				info->partitioned = true;
		}

	} else if (pdata->nr_parts) {
		dev_warn(&pdev->dev, "ignoring %d default partitions on %s\n",
				pdata->nr_parts, info->mtd.name);
	}

	/* If there's no partition info, just package the whole chip
	 * as a single MTD device.
	 */
	if (!info->partitioned)
		ret = add_mtd_device(&info->mtd) ? -ENODEV : 0;

	if (ret < 0)
		goto err_scan;

	val = davinci_nand_readl(info, NRCSR_OFFSET);
	dev_info(&pdev->dev, "controller rev. %d.%d\n",
	       (val >> 8) & 0xff, val & 0xff);

	return 0;

err_scan:
	clk_disable(info->clk);

err_clk_enable:
	clk_put(info->clk);

	spin_lock_irq(&davinci_nand_lock);
	if (ecc_mode == NAND_ECC_HW_SYNDROME)
		ecc4_busy = false;
	spin_unlock_irq(&davinci_nand_lock);

err_ecc:
err_clk:
err_ioremap:
	if (base)
		iounmap(base);
	if (vaddr)
		iounmap(vaddr);

err_nomem:
	kfree(info);
	return ret;
}

static int __exit nand_davinci_remove(struct platform_device *pdev)
{
	struct davinci_nand_info *info = platform_get_drvdata(pdev);
	int status;

	if (mtd_has_partitions() && info->partitioned)
		status = del_mtd_partitions(&info->mtd);
	else
		status = del_mtd_device(&info->mtd);

	spin_lock_irq(&davinci_nand_lock);
	if (info->chip.ecc.mode == NAND_ECC_HW_SYNDROME)
		ecc4_busy = false;
	spin_unlock_irq(&davinci_nand_lock);

	iounmap(info->base);
	iounmap(info->vaddr);

	nand_release(&info->mtd);

	clk_disable(info->clk);
	clk_put(info->clk);

	kfree(info);

	return 0;
}

static struct platform_driver nand_davinci_driver = {
	.remove		= __exit_p(nand_davinci_remove),
	.driver		= {
		.name	= "davinci_nand",
	},
};
MODULE_ALIAS("platform:davinci_nand");

static int __init nand_davinci_init(void)
{
	return platform_driver_probe(&nand_davinci_driver, nand_davinci_probe);
}
module_init(nand_davinci_init);

static void __exit nand_davinci_exit(void)
{
	platform_driver_unregister(&nand_davinci_driver);
}
module_exit(nand_davinci_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Texas Instruments");
MODULE_DESCRIPTION("Davinci NAND flash driver");