17d47bd80f3e3eddc254bacedfea65b312443e70
2 * YAFFS: Yet another Flash File System . A NAND-flash specific file system.
4 * Copyright (C) 2002-2011 Aleph One Ltd.
5 * for Toby Churchill Ltd and Brightstar Engineering
7 * Created by Charles Manning <charles@aleph1.co.uk>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU Lesser General Public License version 2.1 as
11 * published by the Free Software Foundation.
13 * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
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.
22 * Thus, two such ECC blocks are used on a 512-byte NAND page.
26 #ifndef __YAFFS_ECC_H__
27 #define __YAFFS_ECC_H__
29 struct yaffs_ecc_other
{
30 unsigned char col_parity
;
32 unsigned line_parity_prime
;
35 void yaffs_ecc_calc(const unsigned char *data
, unsigned char *ecc
);
36 int yaffs_ecc_correct(unsigned char *data
, unsigned char *read_ecc
,
37 const unsigned char *test_ecc
);
39 void yaffs_ecc_calc_other(const unsigned char *data
, unsigned n_bytes
,
40 struct yaffs_ecc_other
*ecc
);
41 int yaffs_ecc_correct_other(unsigned char *data
, unsigned n_bytes
,
42 struct yaffs_ecc_other
*read_ecc
,
43 const struct yaffs_ecc_other
*test_ecc
);