summaryrefslogtreecommitdiffstats
path: root/drivers/mtd/nand/nomadik_nand.c
blob: 768b19c7be6b3536f701d8ff6b4d74a94cc76877 (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
/*
 *  drivers/mtd/nand/nomadik_nand.c
 *
 *  Overview:
 *  	Driver for on-board NAND flash on Nomadik Platforms
 *
 * Copyright (C) 2007 STMicroelectronics Pvt. Ltd.
 * Author: Sachin Verma <sachin.verma@st.com>
 *
 * Copyright (C) 2009 Alessandro Rubini
 *
 * 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.
 *
 */

#include <common.h>
#include <driver.h>
#include <malloc.h>
#include <init.h>

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

#include <io.h>
#include <mach/nand.h>
#include <mach/fsmc.h>

#include <errno.h>

struct nomadik_nand_host {
	struct mtd_info		mtd;
	struct nand_chip	nand;
	void __iomem *cmd_va;
	void __iomem *addr_va;
	struct nand_bbt_descr *bbt_desc;
};

static inline int parity(int b) /* uses low 8 bits: returns 0 or all-1 */
{
	b = b ^ (b >> 4);
	b = b ^ (b >> 2);
	return (b ^ (b >> 1)) & 1
		? ~0 : 0;
}

/*
 * This is the ECC routine used in hardware, according to the manual.
 * HW claims to make the calculation but not the correction. However,
 * I haven't managed to get the desired data out of it; so do it in sw.
 * There is problably some errata involved, but currently miss the info.
 */
static int nomadik_ecc512_calc(struct mtd_info *mtd, const u_char *data,
			u_char *ecc)
{
	int gpar = 0;
	int i, val, par;
	int pbits = 0;		/* P8, P16, ... P2048 */
	int pprime = 0;		/* P8', P16', ... P2048' */
	int lowbits;		/* P1, P2, P4 and primes */

	for (i = 0; i < 512; i++) {
		par = parity((val = data[i]));
		gpar ^= val;
		pbits ^= (i & par);
	}
	/*
	 * Ok, now gpar is global parity (xor of all bytes)
	 * pbits are all the parity bits (non-prime ones)
	 */
	par = parity(gpar);
	pprime = pbits ^ par;
	/* Put low bits in the right position for ecc[2] (bits 7..2) */
	lowbits = 0
		| (parity(gpar & 0xf0) & 0x80)	/* P4  */
		| (parity(gpar & 0x0f) & 0x40)	/* P4' */
		| (parity(gpar & 0xcc) & 0x20)	/* P2  */
		| (parity(gpar & 0x33) & 0x10)	/* P2' */
		| (parity(gpar & 0xaa) & 0x08)	/* P1  */
		| (parity(gpar & 0x55) & 0x04);	/* P1' */

	ecc[2] = ~(lowbits | ((pbits & 0x100) >> 7) | ((pprime & 0x100) >> 8));
	/* now intermix bits for ecc[1] (P1024..P128') and ecc[0] (P64..P8') */
	ecc[1] = ~(    (pbits & 0x80) >> 0  | ((pprime & 0x80) >> 1)
		    | ((pbits & 0x40) >> 1) | ((pprime & 0x40) >> 2)
		    | ((pbits & 0x20) >> 2) | ((pprime & 0x20) >> 3)
		    | ((pbits & 0x10) >> 3) | ((pprime & 0x10) >> 4));

	ecc[0] = ~(    (pbits & 0x8) << 4  | ((pprime & 0x8) << 3)
		    | ((pbits & 0x4) << 3) | ((pprime & 0x4) << 2)
		    | ((pbits & 0x2) << 2) | ((pprime & 0x2) << 1)
		    | ((pbits & 0x1) << 1) | ((pprime & 0x1) << 0));
	return 0;
}

static int nomadik_ecc512_correct(struct mtd_info *mtd, uint8_t *dat,
				uint8_t *r_ecc, uint8_t *c_ecc)
{
	struct nand_chip *chip = mtd->priv;
	uint32_t r, c, d, diff; /*read, calculated, xor of them */

	if (!memcmp(r_ecc, c_ecc, chip->ecc.bytes))
		return 0;

	/* Reorder the bytes into ascending-order 24 bits -- see manual */
	r = r_ecc[2] << 22 | r_ecc[1] << 14 | r_ecc[0] << 6 | r_ecc[2] >> 2;
	c = c_ecc[2] << 22 | c_ecc[1] << 14 | c_ecc[0] << 6 | c_ecc[2] >> 2;
	diff = (r ^ c) & ((1 << 24) - 1); /* use 24 bits only */

	/* If 12 bits are different, one per pair, it's correctable */
	if (((diff | (diff>>1)) & 0x555555) == 0x555555) {
		int bit = ((diff & 2) >> 1)
			| ((diff & 0x8) >> 2) | ((diff & 0x20) >> 3);
		int byte;

		d = diff >> 6; /* remove bit-order info */
		byte =  ((d & 2) >> 1)
			| ((d & 0x8) >> 2) | ((d & 0x20) >> 3)
			| ((d & 0x80) >> 4) | ((d & 0x200) >> 5)
			| ((d & 0x800) >> 6) | ((d & 0x2000) >> 7)
			| ((d & 0x8000) >> 8) | ((d & 0x20000) >> 9);
		/* correct the single bit */
		dat[byte] ^= 1 << bit;
		return 0;
	}
	/* If 1 bit only differs, it's one bit error in ECC, ignore */
	if ((diff ^ (1 << (ffs(diff) - 1))) == 0)
		return 0;
	/* Otherwise, uncorrectable */
	return -1;
}

static struct nand_ecclayout nomadik_ecc_layout = {
	.eccbytes = 3 * 4,
	.eccpos = { /* each subpage has 16 bytes: pos 2,3,4 hosts ECC */
		0x02, 0x03, 0x04,
		0x12, 0x13, 0x14,
		0x22, 0x23, 0x24,
		0x32, 0x33, 0x34},
	/* let's keep bytes 5,6,7 for us, just in case we change ECC algo */
	.oobfree = { {0x08, 0x08}, {0x18, 0x08}, {0x28, 0x08}, {0x38, 0x08} },
};

static void nomadik_ecc_control(struct mtd_info *mtd, int mode)
{
	/* No need to enable hw ecc, it's on by default */
}

static void nomadik_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
{
	struct nand_chip *nand = mtd->priv;
	struct nomadik_nand_host *host = nand->priv;

	if (cmd == NAND_CMD_NONE)
		return;

	if (ctrl & NAND_CLE)
		writeb(cmd, host->cmd_va);
	else
		writeb(cmd, host->addr_va);
}

static int nomadik_nand_probe(struct device_d *dev)
{
	struct nomadik_nand_platform_data *pdata = dev->platform_data;
	struct nomadik_nand_host *host;
	struct mtd_info *mtd;
	struct nand_chip *nand;
	int ret = 0;

	/* Allocate memory for the device structure (and zero it) */
	host = kzalloc(sizeof(struct nomadik_nand_host), GFP_KERNEL);
	if (!host) {
		dev_err(dev, "Failed to allocate device structure.\n");
		return -ENOMEM;
	}

	/* Call the client's init function, if any */
	if (pdata->init && (ret = pdata->init()) < 0) {
		dev_err(dev, "Init function failed\n");
		goto err;
	}

	host->cmd_va = dev_request_mem_region_by_name(dev, "nand_cmd");
	host->addr_va = dev_request_mem_region_by_name(dev, "nand_addr");

	/* Link all private pointers */
	mtd = &host->mtd;
	nand = &host->nand;
	mtd->priv = nand;
	nand->priv = host;
	mtd->parent = dev;

	nand->IO_ADDR_W = nand->IO_ADDR_R = dev_request_mem_region_by_name(dev, "nand_data");
	nand->cmd_ctrl = nomadik_cmd_ctrl;

	nand->ecc.mode = NAND_ECC_HW;
	nand->ecc.layout = &nomadik_ecc_layout;
	nand->ecc.calculate = nomadik_ecc512_calc;
	nand->ecc.correct = nomadik_ecc512_correct;
	nand->ecc.hwctl = nomadik_ecc_control;
	nand->ecc.size = 512;
	nand->ecc.bytes = 3;

	nand->options = pdata->options;

	/*
	 * Scan to find existance of the device
	 */
	if (nand_scan(&host->mtd, 1)) {
		ret = -ENXIO;
		goto err;
	}

	pr_info("Registering %s as whole device\n", mtd->name);
	add_mtd_device(mtd, "nand");

	return 0;

err:
	kfree(host);
	return ret;
}

static struct driver_d nomadik_nand_driver = {
	.probe = nomadik_nand_probe,
	.name = "nomadik_nand",
};

static int __init nand_nomadik_init(void)
{
	pr_info("Nomadik NAND driver\n");
	return platform_driver_register(&nomadik_nand_driver);
}

device_initcall(nand_nomadik_init);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("ST Microelectronics (sachin.verma@st.com)");
MODULE_DESCRIPTION("NAND driver for Nomadik Platform");