2 * YAFFS: Yet another Flash File System . A NAND-flash specific file system.
4 * Copyright (C) 2002-2018 Aleph One Ltd.
6 * Created by Charles Manning <charles@aleph1.co.uk>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU Lesser General Public License version 2.1 as
10 * published by the Free Software Foundation.
12 * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
16 * This code implements the ECC algorithm used in SmartMedia.
18 * The ECC comprises 22 bits of parity information and is stuffed into 3 bytes.
19 * The two unused bit are set to 1.
20 * The ECC can correct single bit errors in a 256-byte page of data.
21 * Thus, two such ECC blocks are used on a 512-byte NAND page.
25 #ifndef __YAFFS_ECC_H__
26 #define __YAFFS_ECC_H__
28 struct yaffs_ecc_other {
29 unsigned char col_parity;
31 unsigned line_parity_prime;
34 void yaffs_ecc_calc(const unsigned char *data, unsigned char *ecc);
35 int yaffs_ecc_correct(unsigned char *data, unsigned char *read_ecc,
36 const unsigned char *test_ecc);
38 void yaffs_ecc_calc_other(const unsigned char *data, unsigned n_bytes,
39 struct yaffs_ecc_other *ecc);
40 int yaffs_ecc_correct_other(unsigned char *data, unsigned n_bytes,
41 struct yaffs_ecc_other *read_ecc,
42 const struct yaffs_ecc_other *test_ecc);