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* YAFFS: Yet another Flash File System . A NAND-flash specific file system.
* Copyright (C) 2002-2007 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__
typedef struct {
unsigned char colParity;
unsigned lineParity;
unsigned lineParityPrime;
} yaffs_ECCOther;
void yaffs_ECCCalculate(const unsigned char *data, unsigned char *ecc);
int yaffs_ECCCorrect(unsigned char *data, unsigned char *read_ecc,
const unsigned char *test_ecc);
void yaffs_ECCCalculateOther(const unsigned char *data, unsigned nBytes,
yaffs_ECCOther * ecc);
int yaffs_ECCCorrectOther(unsigned char *data, unsigned nBytes,
yaffs_ECCOther * read_ecc,
const yaffs_ECCOther * test_ecc);