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1 /* |
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2 * YAFFS: Yet another FFS. A NAND-flash specific file system. |
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3 * |
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4 * yaffs_ecc.c: ECC generation/correction algorithms. |
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5 * |
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6 * Copyright (C) 2002 Aleph One Ltd. |
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7 * |
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8 * Created by Charles Manning <charles@aleph1.co.uk> |
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9 * |
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10 * This program is free software; you can redistribute it and/or modify |
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11 * it under the terms of the GNU General Public License version 2 as |
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12 * published by the Free Software Foundation. |
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13 * |
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14 */ |
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15 |
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16 /* |
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17 * This code implements the ECC algorithm used in SmartMedia. |
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18 * |
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19 * The ECC comprises 22 bits of parity information and is stuffed into 3 bytes. |
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20 * The two unused bit are set to 1. |
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21 * The ECC can correct single bit errors in a 256-byte page of data. Thus, two such ECC |
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22 * blocks are used on a 512-byte NAND page. |
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23 * |
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24 */ |
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25 |
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26 #ifndef __YAFFS_ECC_H__ |
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27 #define __YAFFS_ECC_H__ |
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28 |
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29 typedef struct { |
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30 unsigned char colParity; |
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31 unsigned lineParity; |
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32 unsigned lineParityPrime; |
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33 } yaffs_ECCOther; |
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34 |
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35 void yaffs_ECCCalculate(const unsigned char *data, unsigned char *ecc); |
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36 int yaffs_ECCCorrect(unsigned char *data, unsigned char *read_ecc, |
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37 const unsigned char *test_ecc); |
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38 |
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39 void yaffs_ECCCalculateOther(const unsigned char *data, unsigned nBytes, |
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40 yaffs_ECCOther * ecc); |
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41 int yaffs_ECCCorrectOther(unsigned char *data, unsigned nBytes, |
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42 yaffs_ECCOther * read_ecc, |
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43 const yaffs_ECCOther * test_ecc); |
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44 #endif |
