drivers/char/ftape/lowlevel/ftape-ecc.h

   1 #ifndef _FTAPE_ECC_H_
   2 #define _FTAPE_ECC_H_
   3
   4 /*
   5  *      Copyright (C) 1993 Ning and David Mosberger.
   6  *      Original:
   7  *      Copyright (C) 1993 Bas Laarhoven.
   8  *      Copyright (C) 1992 David L. Brown, Jr.
   9
  10  This program is free software; you can redistribute it and/or
  11  modify it under the terms of the GNU General Public License as
  12  published by the Free Software Foundation; either version 2, or (at
  13  your option) any later version.
  14
  15  This program is distributed in the hope that it will be useful, but
  16  WITHOUT ANY WARRANTY; without even the implied warranty of
  17  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  General Public License for more details.
  19
  20  You should have received a copy of the GNU General Public License
  21  along with this program; see the file COPYING.  If not, write to
  22  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
  23  USA.
  24
  25  *
  26  * $Source: /homes/cvs/ftape-stacked/ftape/lowlevel/ftape-ecc.h,v $
  27  * $Revision: 1.2 $
  28  * $Date: 1997/10/05 19:18:11 $
  29  *
  30  *      This file contains the definitions for the
  31  *      Reed-Solomon error correction code
  32  *      for the QIC-40/80 tape streamer device driver.
  33  */
  34
  35 #include "../lowlevel/ftape-bsm.h"
  36
  37 #define BAD_CLEAR(entry) ((entry)=0)
  38 #define BAD_SET(entry,sector) ((entry)|=(1<<(sector)))
  39 #define BAD_CHECK(entry,sector) ((entry)&(1<<(sector)))
  40
  41 /*
  42  * Return values for ecc_correct_data:
  43  */
  44 enum {
  45         ECC_OK,                 /* Data was correct. */
  46         ECC_CORRECTED,          /* Correctable error in data. */
  47         ECC_FAILED,             /* Could not correct data. */
  48 };
  49
  50 /*
  51  * Representation of an in memory segment.  MARKED_BAD lists the
  52  * sectors that were marked bad during formatting.  If the N-th sector
  53  * in a segment is marked bad, bit 1<<N will be set in MARKED_BAD.
  54  * The sectors should be read in from the disk and packed, as if the
  55  * bad sectors were not there, and the segment just contained fewer
  56  * sectors.  READ_SECTORS is a bitmap of errors encountered while
  57  * reading the data.  These offsets are relative to the packed data.
  58  * BLOCKS is a count of the sectors not marked bad.  This is just to
  59  * prevent having to count the zero bits in MARKED_BAD each time this
  60  * is needed.  DATA is the actual sector packed data from (or to) the
  61  * tape.
  62  */
  63  struct memory_segment {
  64         SectorMap marked_bad;
  65         SectorMap read_bad;
  66         int blocks;
  67         __u8 *data;
  68         SectorMap corrected;
  69  };
  70
  71 /*
  72  * ecc.c defined global variables:
  73  */
  74 #ifdef TEST
  75 extern int ftape_ecc_tracing;
  76 #endif
  77
  78 /*
  79  * ecc.c defined global functions:
  80  */
  81 extern int ftape_ecc_correct_data(struct memory_segment *data);
  82 extern int ftape_ecc_set_segment_parity(struct memory_segment *data);
  83
  84 #endif  /* _FTAPE_ECC_H_ */