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Commit | Line | Data |
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0e8cc8bd | 1 | /* |
4b070809 | 2 | * YAFFS: Yet another Flash File System . A NAND-flash specific file system. |
0e8cc8bd | 3 | * |
753ac610 | 4 | * Copyright (C) 2002-2011 Aleph One Ltd. |
0e8cc8bd WJ |
5 | * for Toby Churchill Ltd and Brightstar Engineering |
6 | * | |
7 | * Created by Charles Manning <charles@aleph1.co.uk> | |
8 | * | |
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. | |
12 | * | |
13 | * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL. | |
14 | */ | |
15 | ||
753ac610 CM |
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. | |
22 | * Thus, two such ECC blocks are used on a 512-byte NAND page. | |
23 | * | |
24 | */ | |
0e8cc8bd WJ |
25 | |
26 | #ifndef __YAFFS_ECC_H__ | |
27 | #define __YAFFS_ECC_H__ | |
28 | ||
753ac610 CM |
29 | struct yaffs_ecc_other { |
30 | unsigned char col_parity; | |
31 | unsigned line_parity; | |
32 | unsigned line_parity_prime; | |
33 | }; | |
0e8cc8bd | 34 | |
753ac610 CM |
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); | |
0e8cc8bd | 38 | |
753ac610 CM |
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); | |
0e8cc8bd | 44 | #endif |