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_ */
85
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