1/*
2 * YAFFS: Yet another FFS. A NAND-flash specific file system.
3 *
4 * yaffs_ecc.c: ECC generation/correction algorithms.
5 *
6 * Copyright (C) 2002 Aleph One Ltd.
7 *
8 * Created by Charles Manning <charles@aleph1.co.uk>
9 *
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.
13 *
14 */
15
16 /*
17  * This code implements the ECC algorithm used in SmartMedia.
18  *
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.
23  *
24  */
25
26#ifndef __YAFFS_ECC_H__
27#define __YAFFS_ECC_H__
28
29typedef struct {
30	unsigned char colParity;
31	unsigned lineParity;
32	unsigned lineParityPrime;
33} yaffs_ECCOther;
34
35void yaffs_ECCCalculate(const unsigned char *data, unsigned char *ecc);
36int yaffs_ECCCorrect(unsigned char *data, unsigned char *read_ecc,
37		     const unsigned char *test_ecc);
38
39void yaffs_ECCCalculateOther(const unsigned char *data, unsigned nBytes,
40			     yaffs_ECCOther * ecc);
41int yaffs_ECCCorrectOther(unsigned char *data, unsigned nBytes,
42			  yaffs_ECCOther * read_ecc,
43			  const yaffs_ECCOther * test_ecc);
44#endif
45