2 * This file contains an ECC algorithm from Toshiba that allows for detection
3 * and correction of 1-bit errors in a 256 byte block of data.
5 * [ Extracted from the initial code found in some early Linux versions.
6 * The current Linux code is bigger while being faster, but this is of
7 * no real benefit when the bottleneck largely remains the JTAG link. ]
9 * Copyright (C) 2000-2004 Steven J. Hill (sjhill at realitydiluted.com)
10 * Toshiba America Electronics Components, Inc.
12 * Copyright (C) 2006 Thomas Gleixner <tglx at linutronix.de>
14 * This file is free software; you can redistribute it and/or modify it
15 * under the terms of the GNU General Public License as published by the
16 * Free Software Foundation; either version 2 or (at your option) any
19 * This file is distributed in the hope that it will be useful, but WITHOUT
20 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
21 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
24 * You should have received a copy of the GNU General Public License along
25 * with this file; if not, write to the Free Software Foundation, Inc.,
26 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
28 * As a special exception, if other files instantiate templates or use
29 * macros or inline functions from these files, or you compile these
30 * files and link them with other works to produce a work based on these
31 * files, these files do not by themselves cause the resulting work to be
32 * covered by the GNU General Public License. However the source code for
33 * these files must still be made available in accordance with section (3)
34 * of the GNU General Public License.
36 * This exception does not invalidate any other reasons why a work based on
37 * this file might be covered by the GNU General Public License.
44 #include "replacements.h"
51 * Pre-calculated 256-way 1 byte column parity
53 static const u8 nand_ecc_precalc_table[] = {
54 0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00,
55 0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,
56 0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,
57 0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,
58 0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,
59 0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,
60 0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,
61 0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,
62 0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,
63 0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,
64 0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,
65 0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,
66 0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,
67 0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,
68 0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,
69 0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00
73 * nand_calculate_ecc - Calculate 3-byte ECC for 256-byte block
75 int nand_calculate_ecc(struct nand_device_s *device, const u8 *dat, u8 *ecc_code)
77 u8 idx, reg1, reg2, reg3, tmp1, tmp2;
80 /* Initialize variables */
81 reg1 = reg2 = reg3 = 0;
83 /* Build up column parity */
84 for(i = 0; i < 256; i++) {
85 /* Get CP0 - CP5 from table */
86 idx = nand_ecc_precalc_table[*dat++];
89 /* All bit XOR = 1 ? */
96 /* Create non-inverted ECC code from line parity */
97 tmp1 = (reg3 & 0x80) >> 0; /* B7 -> B7 */
98 tmp1 |= (reg2 & 0x80) >> 1; /* B7 -> B6 */
99 tmp1 |= (reg3 & 0x40) >> 1; /* B6 -> B5 */
100 tmp1 |= (reg2 & 0x40) >> 2; /* B6 -> B4 */
101 tmp1 |= (reg3 & 0x20) >> 2; /* B5 -> B3 */
102 tmp1 |= (reg2 & 0x20) >> 3; /* B5 -> B2 */
103 tmp1 |= (reg3 & 0x10) >> 3; /* B4 -> B1 */
104 tmp1 |= (reg2 & 0x10) >> 4; /* B4 -> B0 */
106 tmp2 = (reg3 & 0x08) << 4; /* B3 -> B7 */
107 tmp2 |= (reg2 & 0x08) << 3; /* B3 -> B6 */
108 tmp2 |= (reg3 & 0x04) << 3; /* B2 -> B5 */
109 tmp2 |= (reg2 & 0x04) << 2; /* B2 -> B4 */
110 tmp2 |= (reg3 & 0x02) << 2; /* B1 -> B3 */
111 tmp2 |= (reg2 & 0x02) << 1; /* B1 -> B2 */
112 tmp2 |= (reg3 & 0x01) << 1; /* B0 -> B1 */
113 tmp2 |= (reg2 & 0x01) << 0; /* B7 -> B0 */
115 /* Calculate final ECC code */
123 ecc_code[2] = ((~reg1) << 2) | 0x03;