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https://github.com/brain-hackers/u-boot-brain
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83d290c56f
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
175 lines
5.8 KiB
C
175 lines
5.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* This file contains an ECC algorithm from Toshiba that detects and
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* corrects 1 bit errors in a 256 byte block of data.
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*
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* drivers/mtd/nand/nand_ecc.c
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*
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* Copyright (C) 2000-2004 Steven J. Hill (sjhill@realitydiluted.com)
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* Toshiba America Electronics Components, Inc.
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*
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* Copyright (C) 2006 Thomas Gleixner <tglx@linutronix.de>
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*
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* As a special exception, if other files instantiate templates or use
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* macros or inline functions from these files, or you compile these
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* files and link them with other works to produce a work based on these
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* files, these files do not by themselves cause the resulting work to be
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* covered by the GNU General Public License. However the source code for
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* these files must still be made available in accordance with section (3)
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* of the GNU General Public License.
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*
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* This exception does not invalidate any other reasons why a work based on
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* this file might be covered by the GNU General Public License.
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*/
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#include <common.h>
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#include <linux/errno.h>
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/nand_ecc.h>
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/*
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* NAND-SPL has no sofware ECC for now, so don't include nand_calculate_ecc(),
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* only nand_correct_data() is needed
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*/
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#if !defined(CONFIG_NAND_SPL) || defined(CONFIG_SPL_NAND_SOFTECC)
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/*
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* Pre-calculated 256-way 1 byte column parity
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*/
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static const u_char nand_ecc_precalc_table[] = {
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0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00,
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0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,
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0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,
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0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,
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0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,
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0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,
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0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,
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0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,
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0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,
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0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,
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0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,
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0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,
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0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,
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0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,
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0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,
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0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00
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};
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/**
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* nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256-byte block
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* @mtd: MTD block structure
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* @dat: raw data
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* @ecc_code: buffer for ECC
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*/
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int nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
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u_char *ecc_code)
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{
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uint8_t idx, reg1, reg2, reg3, tmp1, tmp2;
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int i;
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/* Initialize variables */
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reg1 = reg2 = reg3 = 0;
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/* Build up column parity */
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for(i = 0; i < 256; i++) {
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/* Get CP0 - CP5 from table */
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idx = nand_ecc_precalc_table[*dat++];
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reg1 ^= (idx & 0x3f);
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/* All bit XOR = 1 ? */
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if (idx & 0x40) {
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reg3 ^= (uint8_t) i;
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reg2 ^= ~((uint8_t) i);
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}
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}
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/* Create non-inverted ECC code from line parity */
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tmp1 = (reg3 & 0x80) >> 0; /* B7 -> B7 */
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tmp1 |= (reg2 & 0x80) >> 1; /* B7 -> B6 */
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tmp1 |= (reg3 & 0x40) >> 1; /* B6 -> B5 */
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tmp1 |= (reg2 & 0x40) >> 2; /* B6 -> B4 */
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tmp1 |= (reg3 & 0x20) >> 2; /* B5 -> B3 */
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tmp1 |= (reg2 & 0x20) >> 3; /* B5 -> B2 */
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tmp1 |= (reg3 & 0x10) >> 3; /* B4 -> B1 */
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tmp1 |= (reg2 & 0x10) >> 4; /* B4 -> B0 */
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tmp2 = (reg3 & 0x08) << 4; /* B3 -> B7 */
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tmp2 |= (reg2 & 0x08) << 3; /* B3 -> B6 */
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tmp2 |= (reg3 & 0x04) << 3; /* B2 -> B5 */
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tmp2 |= (reg2 & 0x04) << 2; /* B2 -> B4 */
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tmp2 |= (reg3 & 0x02) << 2; /* B1 -> B3 */
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tmp2 |= (reg2 & 0x02) << 1; /* B1 -> B2 */
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tmp2 |= (reg3 & 0x01) << 1; /* B0 -> B1 */
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tmp2 |= (reg2 & 0x01) << 0; /* B7 -> B0 */
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/* Calculate final ECC code */
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ecc_code[0] = ~tmp1;
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ecc_code[1] = ~tmp2;
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ecc_code[2] = ((~reg1) << 2) | 0x03;
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return 0;
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}
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#endif /* CONFIG_NAND_SPL */
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static inline int countbits(uint32_t byte)
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{
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int res = 0;
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for (;byte; byte >>= 1)
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res += byte & 0x01;
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return res;
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}
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/**
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* nand_correct_data - [NAND Interface] Detect and correct bit error(s)
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* @mtd: MTD block structure
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* @dat: raw data read from the chip
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* @read_ecc: ECC from the chip
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* @calc_ecc: the ECC calculated from raw data
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*
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* Detect and correct a 1 bit error for 256 byte block
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*/
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int nand_correct_data(struct mtd_info *mtd, u_char *dat,
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u_char *read_ecc, u_char *calc_ecc)
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{
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uint8_t s0, s1, s2;
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s1 = calc_ecc[0] ^ read_ecc[0];
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s0 = calc_ecc[1] ^ read_ecc[1];
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s2 = calc_ecc[2] ^ read_ecc[2];
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if ((s0 | s1 | s2) == 0)
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return 0;
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/* Check for a single bit error */
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if( ((s0 ^ (s0 >> 1)) & 0x55) == 0x55 &&
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((s1 ^ (s1 >> 1)) & 0x55) == 0x55 &&
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((s2 ^ (s2 >> 1)) & 0x54) == 0x54) {
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uint32_t byteoffs, bitnum;
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byteoffs = (s1 << 0) & 0x80;
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byteoffs |= (s1 << 1) & 0x40;
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byteoffs |= (s1 << 2) & 0x20;
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byteoffs |= (s1 << 3) & 0x10;
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byteoffs |= (s0 >> 4) & 0x08;
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byteoffs |= (s0 >> 3) & 0x04;
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byteoffs |= (s0 >> 2) & 0x02;
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byteoffs |= (s0 >> 1) & 0x01;
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bitnum = (s2 >> 5) & 0x04;
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bitnum |= (s2 >> 4) & 0x02;
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bitnum |= (s2 >> 3) & 0x01;
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dat[byteoffs] ^= (1 << bitnum);
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return 1;
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}
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if(countbits(s0 | ((uint32_t)s1 << 8) | ((uint32_t)s2 <<16)) == 1)
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return 1;
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return -EBADMSG;
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}
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