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