drivers/isdn/hisax/isdnhdlc.h

   1 /*
   2  * isdnhdlc.h  --  General purpose ISDN HDLC decoder.
   3  *
   4  * Implementation of a HDLC decoder/encoder in software.
   5  * Neccessary because some ISDN devices don't have HDLC
   6  * controllers. Also included: a bit reversal table.
   7  *
   8  *Copyright (C) 2002    Wolfgang Mües      <wolfgang@iksw-muees.de>
   9  *              2001    Frode Isaksen      <fisaksen@bewan.com>
  10  *              2001    Kai Germaschewski  <kai.germaschewski@gmx.de>
  11  *
  12  *      This program is free software; you can redistribute it and/or modify
  13  *      it under the terms of the GNU General Public License as published by
  14  *      the Free Software Foundation; either version 2 of the License, or
  15  *      (at your option) any later version.
  16  *
  17  *      This program is distributed in the hope that it will be useful,
  18  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  *      GNU General Public License for more details.
  21  *
  22  *      You should have received a copy of the GNU General Public License
  23  *      along with this program; if not, write to the Free Software
  24  *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  25  */
  26
  27 #ifndef __ISDNHDLC_H__
  28 #define __ISDNHDLC_H__
  29
  30 struct isdnhdlc_vars {
  31         int bit_shift;
  32         int hdlc_bits1;
  33         int data_bits;
  34         int ffbit_shift;        // encoding only
  35         int state;
  36         int dstpos;
  37
  38         unsigned short crc;
  39
  40         unsigned char cbin;
  41         unsigned char shift_reg;
  42         unsigned char ffvalue;
  43
  44         int data_received:1;    // set if transferring data
  45         int dchannel:1;         // set if D channel (send idle instead of flags)
  46         int do_adapt56:1;       // set if 56K adaptation
  47         int do_closing:1;       // set if in closing phase (need to send CRC + flag
  48 };
  49
  50
  51 /*
  52   The return value from isdnhdlc_decode is
  53   the frame length, 0 if no complete frame was decoded,
  54   or a negative error number
  55 */
  56 #define HDLC_FRAMING_ERROR     1
  57 #define HDLC_CRC_ERROR         2
  58 #define HDLC_LENGTH_ERROR      3
  59
  60 extern const unsigned char isdnhdlc_bit_rev_tab[256];
  61
  62 extern void isdnhdlc_rcv_init (struct isdnhdlc_vars *hdlc, int do_adapt56);
  63
  64 extern int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, int slen,int *count,
  65                             unsigned char *dst, int dsize);
  66
  67 extern void isdnhdlc_out_init (struct isdnhdlc_vars *hdlc,int is_d_channel,int do_adapt56);
  68
  69 extern int isdnhdlc_encode (struct isdnhdlc_vars *hdlc,const unsigned char *src,unsigned short slen,int *count,
  70                             unsigned char *dst,int dsize);
  71
  72 #endif /* __ISDNHDLC_H__ */