LXR uboot/fs/yaffs2/yaffs

   1/*
   2 * YAFFS: Yet another Flash File System . A NAND-flash specific file system.
   3 *
   4 * Copyright (C) 2002-2011 Aleph One Ltd.
   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
  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 */
  25
  26#ifndef __YAFFS_ECC_H__
  27#define __YAFFS_ECC_H__
  28
  29struct yaffs_ecc_other {
  30        unsigned char col_parity;
  31        unsigned line_parity;
  32        unsigned line_parity_prime;
  33};
  34
  35void yaffs_ecc_calc(const unsigned char *data, unsigned char *ecc);
  36int yaffs_ecc_correct(unsigned char *data, unsigned char *read_ecc,
  37                      const unsigned char *test_ecc);
  38
  39void yaffs_ecc_calc_other(const unsigned char *data, unsigned n_bytes,
  40                          struct yaffs_ecc_other *ecc);
  41int 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);
  44#endif
  45