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Wolfgang Denk932394a2005-08-17 12:55:25 +02001/*
2 * This file contains an ECC algorithm from Toshiba that detects and
3 * corrects 1 bit errors in a 256 byte block of data.
4 *
5 * drivers/mtd/nand/nand_ecc.c
6 *
7 * Copyright (C) 2000-2004 Steven J. Hill (sjhill@realitydiluted.com)
8 * Toshiba America Electronics Components, Inc.
9 *
William Juulcfa460a2007-10-31 13:53:06 +010010 * Copyright (C) 2006 Thomas Gleixner <tglx@linutronix.de>
11 *
Wolfgang Denk1a459662013-07-08 09:37:19 +020012 * SPDX-License-Identifier: GPL-2.0+
Wolfgang Denkac7eb8a2005-09-14 23:53:32 +020013 *
Wolfgang Denk932394a2005-08-17 12:55:25 +020014 * As a special exception, if other files instantiate templates or use
15 * macros or inline functions from these files, or you compile these
16 * files and link them with other works to produce a work based on these
17 * files, these files do not by themselves cause the resulting work to be
18 * covered by the GNU General Public License. However the source code for
19 * these files must still be made available in accordance with section (3)
20 * of the GNU General Public License.
Wolfgang Denkac7eb8a2005-09-14 23:53:32 +020021 *
Wolfgang Denk932394a2005-08-17 12:55:25 +020022 * This exception does not invalidate any other reasons why a work based on
23 * this file might be covered by the GNU General Public License.
24 */
25
26#include <common.h>
27
Scott Woodc45912d2008-10-24 16:20:43 -050028#include <asm/errno.h>
29#include <linux/mtd/mtd.h>
Kim Phillips7d2ab9a2012-10-29 13:34:46 +000030#include <linux/mtd/nand_ecc.h>
Stefan Roese17b5e862007-06-01 15:12:15 +020031
Stefan Roesef40f6db2009-05-20 10:58:03 +020032/* The PPC4xx NDFC uses Smart Media (SMC) bytes order */
33#ifdef CONFIG_NAND_NDFC
34#define CONFIG_MTD_NAND_ECC_SMC
35#endif
36
Stefan Roese17b5e862007-06-01 15:12:15 +020037/*
38 * NAND-SPL has no sofware ECC for now, so don't include nand_calculate_ecc(),
39 * only nand_correct_data() is needed
40 */
41
Ilya Yanok1df308e2011-11-28 06:37:37 +000042#if !defined(CONFIG_NAND_SPL) || defined(CONFIG_SPL_NAND_SOFTECC)
Wolfgang Denk932394a2005-08-17 12:55:25 +020043/*
44 * Pre-calculated 256-way 1 byte column parity
45 */
46static const u_char nand_ecc_precalc_table[] = {
47 0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00,
48 0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,
49 0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,
50 0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,
51 0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,
52 0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,
53 0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,
54 0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,
55 0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,
56 0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,
57 0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,
58 0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,
59 0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,
60 0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,
61 0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,
62 0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00
63};
64
Wolfgang Denk932394a2005-08-17 12:55:25 +020065/**
Stefan Roese17b5e862007-06-01 15:12:15 +020066 * nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256-byte block
Wolfgang Denk932394a2005-08-17 12:55:25 +020067 * @mtd: MTD block structure
68 * @dat: raw data
69 * @ecc_code: buffer for ECC
70 */
Stefan Roese17b5e862007-06-01 15:12:15 +020071int nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
72 u_char *ecc_code)
Wolfgang Denk932394a2005-08-17 12:55:25 +020073{
Stefan Roese17b5e862007-06-01 15:12:15 +020074 uint8_t idx, reg1, reg2, reg3, tmp1, tmp2;
75 int i;
Wolfgang Denkac7eb8a2005-09-14 23:53:32 +020076
Wolfgang Denk932394a2005-08-17 12:55:25 +020077 /* Initialize variables */
78 reg1 = reg2 = reg3 = 0;
Wolfgang Denkac7eb8a2005-09-14 23:53:32 +020079
80 /* Build up column parity */
Stefan Roese17b5e862007-06-01 15:12:15 +020081 for(i = 0; i < 256; i++) {
Wolfgang Denk932394a2005-08-17 12:55:25 +020082 /* Get CP0 - CP5 from table */
Stefan Roese17b5e862007-06-01 15:12:15 +020083 idx = nand_ecc_precalc_table[*dat++];
Wolfgang Denk932394a2005-08-17 12:55:25 +020084 reg1 ^= (idx & 0x3f);
Wolfgang Denkac7eb8a2005-09-14 23:53:32 +020085
Wolfgang Denk932394a2005-08-17 12:55:25 +020086 /* All bit XOR = 1 ? */
87 if (idx & 0x40) {
Stefan Roese17b5e862007-06-01 15:12:15 +020088 reg3 ^= (uint8_t) i;
89 reg2 ^= ~((uint8_t) i);
Wolfgang Denk932394a2005-08-17 12:55:25 +020090 }
91 }
Wolfgang Denkac7eb8a2005-09-14 23:53:32 +020092
Wolfgang Denk932394a2005-08-17 12:55:25 +020093 /* Create non-inverted ECC code from line parity */
Stefan Roese17b5e862007-06-01 15:12:15 +020094 tmp1 = (reg3 & 0x80) >> 0; /* B7 -> B7 */
95 tmp1 |= (reg2 & 0x80) >> 1; /* B7 -> B6 */
96 tmp1 |= (reg3 & 0x40) >> 1; /* B6 -> B5 */
97 tmp1 |= (reg2 & 0x40) >> 2; /* B6 -> B4 */
98 tmp1 |= (reg3 & 0x20) >> 2; /* B5 -> B3 */
99 tmp1 |= (reg2 & 0x20) >> 3; /* B5 -> B2 */
100 tmp1 |= (reg3 & 0x10) >> 3; /* B4 -> B1 */
101 tmp1 |= (reg2 & 0x10) >> 4; /* B4 -> B0 */
102
103 tmp2 = (reg3 & 0x08) << 4; /* B3 -> B7 */
104 tmp2 |= (reg2 & 0x08) << 3; /* B3 -> B6 */
105 tmp2 |= (reg3 & 0x04) << 3; /* B2 -> B5 */
106 tmp2 |= (reg2 & 0x04) << 2; /* B2 -> B4 */
107 tmp2 |= (reg3 & 0x02) << 2; /* B1 -> B3 */
108 tmp2 |= (reg2 & 0x02) << 1; /* B1 -> B2 */
109 tmp2 |= (reg3 & 0x01) << 1; /* B0 -> B1 */
110 tmp2 |= (reg2 & 0x01) << 0; /* B7 -> B0 */
Wolfgang Denkac7eb8a2005-09-14 23:53:32 +0200111
Wolfgang Denk932394a2005-08-17 12:55:25 +0200112 /* Calculate final ECC code */
Stefan Roese17b5e862007-06-01 15:12:15 +0200113#ifdef CONFIG_MTD_NAND_ECC_SMC
114 ecc_code[0] = ~tmp2;
115 ecc_code[1] = ~tmp1;
116#else
117 ecc_code[0] = ~tmp1;
118 ecc_code[1] = ~tmp2;
119#endif
Wolfgang Denk932394a2005-08-17 12:55:25 +0200120 ecc_code[2] = ((~reg1) << 2) | 0x03;
Stefan Roese17b5e862007-06-01 15:12:15 +0200121
Wolfgang Denk932394a2005-08-17 12:55:25 +0200122 return 0;
123}
Stefan Roese17b5e862007-06-01 15:12:15 +0200124#endif /* CONFIG_NAND_SPL */
125
126static inline int countbits(uint32_t byte)
127{
128 int res = 0;
129
130 for (;byte; byte >>= 1)
131 res += byte & 0x01;
132 return res;
133}
Wolfgang Denk932394a2005-08-17 12:55:25 +0200134
135/**
136 * nand_correct_data - [NAND Interface] Detect and correct bit error(s)
137 * @mtd: MTD block structure
138 * @dat: raw data read from the chip
139 * @read_ecc: ECC from the chip
140 * @calc_ecc: the ECC calculated from raw data
141 *
142 * Detect and correct a 1 bit error for 256 byte block
143 */
Stefan Roese17b5e862007-06-01 15:12:15 +0200144int nand_correct_data(struct mtd_info *mtd, u_char *dat,
145 u_char *read_ecc, u_char *calc_ecc)
Wolfgang Denk932394a2005-08-17 12:55:25 +0200146{
Stefan Roese17b5e862007-06-01 15:12:15 +0200147 uint8_t s0, s1, s2;
Wolfgang Denkac7eb8a2005-09-14 23:53:32 +0200148
Stefan Roese17b5e862007-06-01 15:12:15 +0200149#ifdef CONFIG_MTD_NAND_ECC_SMC
150 s0 = calc_ecc[0] ^ read_ecc[0];
151 s1 = calc_ecc[1] ^ read_ecc[1];
152 s2 = calc_ecc[2] ^ read_ecc[2];
153#else
154 s1 = calc_ecc[0] ^ read_ecc[0];
155 s0 = calc_ecc[1] ^ read_ecc[1];
156 s2 = calc_ecc[2] ^ read_ecc[2];
157#endif
158 if ((s0 | s1 | s2) == 0)
Wolfgang Denk932394a2005-08-17 12:55:25 +0200159 return 0;
Wolfgang Denkac7eb8a2005-09-14 23:53:32 +0200160
Stefan Roese17b5e862007-06-01 15:12:15 +0200161 /* Check for a single bit error */
162 if( ((s0 ^ (s0 >> 1)) & 0x55) == 0x55 &&
163 ((s1 ^ (s1 >> 1)) & 0x55) == 0x55 &&
164 ((s2 ^ (s2 >> 1)) & 0x54) == 0x54) {
165
166 uint32_t byteoffs, bitnum;
167
168 byteoffs = (s1 << 0) & 0x80;
169 byteoffs |= (s1 << 1) & 0x40;
170 byteoffs |= (s1 << 2) & 0x20;
171 byteoffs |= (s1 << 3) & 0x10;
172
173 byteoffs |= (s0 >> 4) & 0x08;
174 byteoffs |= (s0 >> 3) & 0x04;
175 byteoffs |= (s0 >> 2) & 0x02;
176 byteoffs |= (s0 >> 1) & 0x01;
177
178 bitnum = (s2 >> 5) & 0x04;
179 bitnum |= (s2 >> 4) & 0x02;
180 bitnum |= (s2 >> 3) & 0x01;
181
182 dat[byteoffs] ^= (1 << bitnum);
183
184 return 1;
Wolfgang Denk932394a2005-08-17 12:55:25 +0200185 }
Wolfgang Denkac7eb8a2005-09-14 23:53:32 +0200186
Stefan Roese17b5e862007-06-01 15:12:15 +0200187 if(countbits(s0 | ((uint32_t)s1 << 8) | ((uint32_t)s2 <<16)) == 1)
188 return 1;
189
Scott Woodc45912d2008-10-24 16:20:43 -0500190 return -EBADMSG;
Wolfgang Denk932394a2005-08-17 12:55:25 +0200191}