| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 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_ */ |