45 lines
1.4 KiB
C
45 lines
1.4 KiB
C
/*
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* YAFFS: Yet another Flash File System . A NAND-flash specific file system.
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*
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* Copyright (C) 2002-2011 Aleph One Ltd.
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* for Toby Churchill Ltd and Brightstar Engineering
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*
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* Created by Charles Manning <charles@aleph1.co.uk>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License version 2.1 as
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* published by the Free Software Foundation.
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*
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* Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
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*/
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/*
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* This code implements the ECC algorithm used in SmartMedia.
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*
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* The ECC comprises 22 bits of parity information and is stuffed into 3 bytes.
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* The two unused bit are set to 1.
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* The ECC can correct single bit errors in a 256-byte page of data.
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* Thus, two such ECC blocks are used on a 512-byte NAND page.
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*
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*/
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#ifndef __YAFFS_ECC_H__
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#define __YAFFS_ECC_H__
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struct yaffs_ecc_other {
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unsigned char col_parity;
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unsigned line_parity;
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unsigned line_parity_prime;
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};
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void yaffs_ecc_calc(const unsigned char *data, unsigned char *ecc);
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int yaffs_ecc_correct(unsigned char *data, unsigned char *read_ecc,
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const unsigned char *test_ecc);
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void yaffs_ecc_calc_other(const unsigned char *data, unsigned n_bytes,
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struct yaffs_ecc_other *ecc);
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int yaffs_ecc_correct_other(unsigned char *data, unsigned n_bytes,
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struct yaffs_ecc_other *read_ecc,
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const struct yaffs_ecc_other *test_ecc);
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#endif
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