From b7b586ac6b6d48f78778a20d7490e022b5ec6c98 Mon Sep 17 00:00:00 2001 From: ntfreak Date: Tue, 12 May 2009 18:32:57 +0000 Subject: - add missing svn props from svn 1768 commit git-svn-id: svn://svn.berlios.de/openocd/trunk@1769 b42882b7-edfa-0310-969c-e2dbd0fdcd60 --- src/flash/nand_ecc_kw.c | 348 ++++++++++++++++++++++++------------------------ 1 file changed, 174 insertions(+), 174 deletions(-) (limited to 'src/flash/nand_ecc_kw.c') diff --git a/src/flash/nand_ecc_kw.c b/src/flash/nand_ecc_kw.c index ecc7adc2..a7fae626 100644 --- a/src/flash/nand_ecc_kw.c +++ b/src/flash/nand_ecc_kw.c @@ -1,174 +1,174 @@ -/* - * Reed-Solomon ECC handling for the Marvell Kirkwood SOC - * Copyright (C) 2009 Marvell Semiconductor, Inc. - * - * Authors: Lennert Buytenhek - * Nicolas Pitre - * - * This file 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 or (at your option) any - * later version. - * - * This file 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. - */ - -#ifdef HAVE_CONFIG_H -#include "config.h" -#endif - -#include -#include "nand.h" - - -/***************************************************************************** - * Arithmetic in GF(2^10) ("F") modulo x^10 + x^3 + 1. - * - * For multiplication, a discrete log/exponent table is used, with - * primitive element x (F is a primitive field, so x is primitive). - */ -#define MODPOLY 0x409 /* x^10 + x^3 + 1 in binary */ - -/* - * Maps an integer a [0..1022] to a polynomial b = gf_exp[a] in - * GF(2^10) mod x^10 + x^3 + 1 such that b = x ^ a. There's two - * identical copies of this array back-to-back so that we can save - * the mod 1023 operation when doing a GF multiplication. - */ -static uint16_t gf_exp[1023 + 1023]; - -/* - * Maps a polynomial b in GF(2^10) mod x^10 + x^3 + 1 to an index - * a = gf_log[b] in [0..1022] such that b = x ^ a. - */ -static uint16_t gf_log[1024]; - -static void gf_build_log_exp_table(void) -{ - int i; - int p_i; - - /* - * p_i = x ^ i - * - * Initialise to 1 for i = 0. - */ - p_i = 1; - - for (i = 0; i < 1023; i++) { - gf_exp[i] = p_i; - gf_exp[i + 1023] = p_i; - gf_log[p_i] = i; - - /* - * p_i = p_i * x - */ - p_i <<= 1; - if (p_i & (1 << 10)) - p_i ^= MODPOLY; - } -} - - -/***************************************************************************** - * Reed-Solomon code - * - * This implements a (1023,1015) Reed-Solomon ECC code over GF(2^10) - * mod x^10 + x^3 + 1, shortened to (520,512). The ECC data consists - * of 8 10-bit symbols, or 10 8-bit bytes. - * - * Given 512 bytes of data, computes 10 bytes of ECC. - * - * This is done by converting the 512 bytes to 512 10-bit symbols - * (elements of F), interpreting those symbols as a polynomial in F[X] - * by taking symbol 0 as the coefficient of X^8 and symbol 511 as the - * coefficient of X^519, and calculating the residue of that polynomial - * divided by the generator polynomial, which gives us the 8 ECC symbols - * as the remainder. Finally, we convert the 8 10-bit ECC symbols to 10 - * 8-bit bytes. - * - * The generator polynomial is hardcoded, as that is faster, but it - * can be computed by taking the primitive element a = x (in F), and - * constructing a polynomial in F[X] with roots a, a^2, a^3, ..., a^8 - * by multiplying the minimal polynomials for those roots (which are - * just 'x - a^i' for each i). - * - * Note: due to unfortunate circumstances, the bootrom in the Kirkwood SOC - * expects the ECC to be computed backward, i.e. from the last byte down - * to the first one. - */ -int nand_calculate_ecc_kw(struct nand_device_s *device, const u8 *data, u8 *ecc) -{ - unsigned int r7, r6, r5, r4, r3, r2, r1, r0; - int i; - static int tables_initialized = 0; - - if (!tables_initialized) { - gf_build_log_exp_table(); - tables_initialized = 1; - } - - /* - * Load bytes 504..511 of the data into r. - */ - r0 = data[504]; - r1 = data[505]; - r2 = data[506]; - r3 = data[507]; - r4 = data[508]; - r5 = data[509]; - r6 = data[510]; - r7 = data[511]; - - - /* - * Shift bytes 503..0 (in that order) into r0, followed - * by eight zero bytes, while reducing the polynomial by the - * generator polynomial in every step. - */ - for (i = 503; i >= -8; i--) { - unsigned int d; - - d = 0; - if (i >= 0) - d = data[i]; - - if (r7) { - u16 *t = gf_exp + gf_log[r7]; - - r7 = r6 ^ t[0x21c]; - r6 = r5 ^ t[0x181]; - r5 = r4 ^ t[0x18e]; - r4 = r3 ^ t[0x25f]; - r3 = r2 ^ t[0x197]; - r2 = r1 ^ t[0x193]; - r1 = r0 ^ t[0x237]; - r0 = d ^ t[0x024]; - } else { - r7 = r6; - r6 = r5; - r5 = r4; - r4 = r3; - r3 = r2; - r2 = r1; - r1 = r0; - r0 = d; - } - } - - ecc[0] = r0; - ecc[1] = (r0 >> 8) | (r1 << 2); - ecc[2] = (r1 >> 6) | (r2 << 4); - ecc[3] = (r2 >> 4) | (r3 << 6); - ecc[4] = (r3 >> 2); - ecc[5] = r4; - ecc[6] = (r4 >> 8) | (r5 << 2); - ecc[7] = (r5 >> 6) | (r6 << 4); - ecc[8] = (r6 >> 4) | (r7 << 6); - ecc[9] = (r7 >> 2); - - return 0; -} +/* + * Reed-Solomon ECC handling for the Marvell Kirkwood SOC + * Copyright (C) 2009 Marvell Semiconductor, Inc. + * + * Authors: Lennert Buytenhek + * Nicolas Pitre + * + * This file 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 or (at your option) any + * later version. + * + * This file 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. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include +#include "nand.h" + + +/***************************************************************************** + * Arithmetic in GF(2^10) ("F") modulo x^10 + x^3 + 1. + * + * For multiplication, a discrete log/exponent table is used, with + * primitive element x (F is a primitive field, so x is primitive). + */ +#define MODPOLY 0x409 /* x^10 + x^3 + 1 in binary */ + +/* + * Maps an integer a [0..1022] to a polynomial b = gf_exp[a] in + * GF(2^10) mod x^10 + x^3 + 1 such that b = x ^ a. There's two + * identical copies of this array back-to-back so that we can save + * the mod 1023 operation when doing a GF multiplication. + */ +static uint16_t gf_exp[1023 + 1023]; + +/* + * Maps a polynomial b in GF(2^10) mod x^10 + x^3 + 1 to an index + * a = gf_log[b] in [0..1022] such that b = x ^ a. + */ +static uint16_t gf_log[1024]; + +static void gf_build_log_exp_table(void) +{ + int i; + int p_i; + + /* + * p_i = x ^ i + * + * Initialise to 1 for i = 0. + */ + p_i = 1; + + for (i = 0; i < 1023; i++) { + gf_exp[i] = p_i; + gf_exp[i + 1023] = p_i; + gf_log[p_i] = i; + + /* + * p_i = p_i * x + */ + p_i <<= 1; + if (p_i & (1 << 10)) + p_i ^= MODPOLY; + } +} + + +/***************************************************************************** + * Reed-Solomon code + * + * This implements a (1023,1015) Reed-Solomon ECC code over GF(2^10) + * mod x^10 + x^3 + 1, shortened to (520,512). The ECC data consists + * of 8 10-bit symbols, or 10 8-bit bytes. + * + * Given 512 bytes of data, computes 10 bytes of ECC. + * + * This is done by converting the 512 bytes to 512 10-bit symbols + * (elements of F), interpreting those symbols as a polynomial in F[X] + * by taking symbol 0 as the coefficient of X^8 and symbol 511 as the + * coefficient of X^519, and calculating the residue of that polynomial + * divided by the generator polynomial, which gives us the 8 ECC symbols + * as the remainder. Finally, we convert the 8 10-bit ECC symbols to 10 + * 8-bit bytes. + * + * The generator polynomial is hardcoded, as that is faster, but it + * can be computed by taking the primitive element a = x (in F), and + * constructing a polynomial in F[X] with roots a, a^2, a^3, ..., a^8 + * by multiplying the minimal polynomials for those roots (which are + * just 'x - a^i' for each i). + * + * Note: due to unfortunate circumstances, the bootrom in the Kirkwood SOC + * expects the ECC to be computed backward, i.e. from the last byte down + * to the first one. + */ +int nand_calculate_ecc_kw(struct nand_device_s *device, const u8 *data, u8 *ecc) +{ + unsigned int r7, r6, r5, r4, r3, r2, r1, r0; + int i; + static int tables_initialized = 0; + + if (!tables_initialized) { + gf_build_log_exp_table(); + tables_initialized = 1; + } + + /* + * Load bytes 504..511 of the data into r. + */ + r0 = data[504]; + r1 = data[505]; + r2 = data[506]; + r3 = data[507]; + r4 = data[508]; + r5 = data[509]; + r6 = data[510]; + r7 = data[511]; + + + /* + * Shift bytes 503..0 (in that order) into r0, followed + * by eight zero bytes, while reducing the polynomial by the + * generator polynomial in every step. + */ + for (i = 503; i >= -8; i--) { + unsigned int d; + + d = 0; + if (i >= 0) + d = data[i]; + + if (r7) { + u16 *t = gf_exp + gf_log[r7]; + + r7 = r6 ^ t[0x21c]; + r6 = r5 ^ t[0x181]; + r5 = r4 ^ t[0x18e]; + r4 = r3 ^ t[0x25f]; + r3 = r2 ^ t[0x197]; + r2 = r1 ^ t[0x193]; + r1 = r0 ^ t[0x237]; + r0 = d ^ t[0x024]; + } else { + r7 = r6; + r6 = r5; + r5 = r4; + r4 = r3; + r3 = r2; + r2 = r1; + r1 = r0; + r0 = d; + } + } + + ecc[0] = r0; + ecc[1] = (r0 >> 8) | (r1 << 2); + ecc[2] = (r1 >> 6) | (r2 << 4); + ecc[3] = (r2 >> 4) | (r3 << 6); + ecc[4] = (r3 >> 2); + ecc[5] = r4; + ecc[6] = (r4 >> 8) | (r5 << 2); + ecc[7] = (r5 >> 6) | (r6 << 4); + ecc[8] = (r6 >> 4) | (r7 << 6); + ecc[9] = (r7 >> 2); + + return 0; +} -- cgit v1.2.3