drivers/char/ftape/zftape/zftape-rw.h

   1 #ifndef _ZFTAPE_RW_H
   2 #define _ZFTAPE_RW_H
   3
   4 /*
   5  * Copyright (C) 1996, 1997 Claus-Justus Heine.
   6
   7  This program is free software; you can redistribute it and/or modify
   8  it under the terms of the GNU General Public License as published by
   9  the Free Software Foundation; either version 2, or (at your option)
  10  any later version.
  11
  12  This program is distributed in the hope that it will be useful,
  13  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  GNU General Public License for more details.
  16
  17  You should have received a copy of the GNU General Public License
  18  along with this program; see the file COPYING.  If not, write to
  19  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  20
  21  *
  22  * $Source: /homes/cvs/ftape-stacked/ftape/zftape/zftape-rw.h,v $
  23  * $Revision: 1.2 $
  24  * $Date: 1997/10/05 19:19:09 $
  25  *
  26  *      This file contains the definitions for the read and write
  27  *      functions for the QIC-117 floppy-tape driver for Linux.
  28  *
  29  */
  30
  31 #include <linux/config.h> /* for CONFIG_ZFT_DFLT_BLK_SZ */
  32 #include "../zftape/zftape-buffers.h"
  33
  34 #define SEGMENTS_PER_TAPE  (ft_segments_per_track * ft_tracks_per_tape)
  35
  36 /*  QIC-113 Rev. G says that `a maximum of 63488 raw bytes may be
  37  *  compressed into a single frame'.
  38  *  Maybe we should stick to 32kb to make it more `beautiful'
  39  */
  40 #define ZFT_MAX_BLK_SZ           (62*1024) /* bytes */
  41 #if !defined(CONFIG_ZFT_DFLT_BLK_SZ)
  42 # define CONFIG_ZFT_DFLT_BLK_SZ   (10*1024) /* bytes, default of gnu tar */
  43 #elif CONFIG_ZFT_DFLT_BLK_SZ == 0
  44 # undef  CONFIG_ZFT_DFLT_BLK_SZ
  45 # define CONFIG_ZFT_DFLT_BLK_SZ 1
  46 #elif (CONFIG_ZFT_DFLT_BLK_SZ % 1024) != 0
  47 # error CONFIG_ZFT_DFLT_BLK_SZ must be 1 or a multiple of 1024
  48 #endif
  49 /* The *optional* compression routines need some overhead per tape
  50  *  block for their purposes. Instead of asking the actual compression
  51  *  implementation how much it needs, we restrict this overhead to be
  52  *  maximal of ZFT_CMPT_OVERHEAD size. We need this for EOT
  53  *  conditions. The tape is assumed to be logical at EOT when the
  54  *  distance from the physical EOT is less than
  55  *  one tape block + ZFT_CMPR_OVERHEAD
  56  */
  57 #define ZFT_CMPR_OVERHEAD 16        /* bytes */
  58
  59 typedef enum
  60 {
  61         zft_idle = 0,
  62         zft_reading,
  63         zft_writing,
  64 } zft_status_enum;
  65
  66 typedef struct               /*  all values measured in bytes */
  67 {
  68         int   seg_pos;       /*  segment currently positioned at */
  69         int   seg_byte_pos;  /*  offset in current segment */
  70         __s64 tape_pos;      /*  real offset from BOT */
  71         __s64 volume_pos;    /*  pos. in uncompressed data stream in
  72                               *  current volume
  73                               */
  74 } zft_position;
  75
  76 extern zft_position zft_pos;
  77 extern __u8 *zft_deblock_buf;
  78 extern __u8 *zft_hseg_buf;
  79 extern int zft_deblock_segment;
  80 extern zft_status_enum zft_io_state;
  81 extern int zft_header_changed;
  82 extern int zft_qic113; /* conform to old specs. and old zftape */
  83 extern int zft_use_compression;
  84 extern unsigned int zft_blk_sz;
  85 extern __s64 zft_capacity;
  86 extern unsigned int zft_written_segments;
  87 extern int zft_label_changed;
  88
  89 /*  zftape-rw.c exported functions
  90  */
  91 extern unsigned int zft_get_seg_sz(unsigned int segment);
  92 extern void  zft_set_flags(unsigned int minor_unit);
  93 extern int   zft_calc_seg_byte_coord(int *seg_byte_pos, __s64 tape_pos);
  94 extern __s64 zft_calc_tape_pos(int segment);
  95 extern __s64 zft_get_capacity(void);
  96 extern void  zft_update_label(__u8 *buffer);
  97 extern int   zft_erase(void);
  98 extern int   zft_verify_write_segments(unsigned int segment,
  99                                        __u8 *data, size_t size, __u8 *buffer);
 100 extern unsigned int zft_get_time(void);
 101 #endif /* _ZFTAPE_RW_H */
 102