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* YAFFS: Yet another Flash File System . A NAND-flash specific file system.
* Copyright (C) 2002-2011 Aleph One Ltd.
* for Toby Churchill Ltd and Brightstar Engineering
* Created by Charles Manning <>
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 2.1 as
* published by the Free Software Foundation.
* Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
* This code implements the ECC algorithm used in SmartMedia.
* The ECC comprises 22 bits of parity information and is stuffed into 3 bytes.
* The two unused bit are set to 1.
* The ECC can correct single bit errors in a 256-byte page of data.
* Thus, two such ECC blocks are used on a 512-byte NAND page.
#ifndef __YAFFS_ECC_H__
#define __YAFFS_ECC_H__
struct yaffs_ecc_other {
unsigned char col_parity;
unsigned line_parity;
unsigned line_parity_prime;
void yaffs_ecc_calc(const unsigned char *data, unsigned char *ecc);
int yaffs_ecc_correct(unsigned char *data, unsigned char *read_ecc,
const unsigned char *test_ecc);
void yaffs_ecc_calc_other(const unsigned char *data, unsigned n_bytes,
struct yaffs_ecc_other *ecc);
int yaffs_ecc_correct_other(unsigned char *data, unsigned n_bytes,
struct yaffs_ecc_other *read_ecc,
const struct yaffs_ecc_other *test_ecc);