2 * YAFFS: Yet another FFS. A NAND-flash specific file system.
4 * yaffs_ecc.c: ECC generation/correction algorithms.
6 * Copyright (C) 2002 Aleph One Ltd.
8 * Created by Charles Manning <charles@aleph1.co.uk>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
17 * This code implements the ECC algorithm used in SmartMedia.
19 * The ECC comprises 22 bits of parity information and is stuffed into 3 bytes.
20 * The two unused bit are set to 1.
21 * The ECC can correct single bit errors in a 256-byte page of data. Thus, two such ECC
22 * blocks are used on a 512-byte NAND page.
26 #ifndef __YAFFS_ECC_H__
27 #define __YAFFS_ECC_H__
30 unsigned char colParity;
32 unsigned lineParityPrime;
35 void yaffs_ECCCalculate(const unsigned char *data, unsigned char *ecc);
36 int yaffs_ECCCorrect(unsigned char *data, unsigned char *read_ecc,
37 const unsigned char *test_ecc);
39 void yaffs_ECCCalculateOther(const unsigned char *data, unsigned nBytes,
40 yaffs_ECCOther * ecc);
41 int yaffs_ECCCorrectOther(unsigned char *data, unsigned nBytes,
42 yaffs_ECCOther * read_ecc,
43 const yaffs_ECCOther * test_ecc);