www.pudn.com > yaffs2.zip > yaffs_ecc.h

/* 
 * YAFFS: Yet another FFS. A NAND-flash specific file system.  
 * 
 * yaffs_ecc.c: ECC generation/correction algorithms. 
 * 
 * Copyright (C) 2002 Aleph One Ltd. 
 * 
 * Created by Charles Manning  
 * 
 * This program is free software; you can redistribute it and/or modify 
 * it under the terms of the GNU General Public License version 2 as 
 * published by the Free Software Foundation. 
 * 
 */ 
  
 /* 
 * 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); 
#endif