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[mirror_ubuntu-zesty-kernel.git] / include / linux / isdn / hdlc.h
1 /*
2 * hdlc.h -- General purpose ISDN HDLC decoder.
3 *
4 * Implementation of a HDLC decoder/encoder in software.
5 * Necessary because some ISDN devices don't have HDLC
6 * controllers.
7 *
8 * Copyright (C)
9 * 2009 Karsten Keil <keil@b1-systems.de>
10 * 2002 Wolfgang Mües <wolfgang@iksw-muees.de>
11 * 2001 Frode Isaksen <fisaksen@bewan.com>
12 * 2001 Kai Germaschewski <kai.germaschewski@gmx.de>
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
18 *
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, write to the Free Software
26 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
27 */
28
29 #ifndef __ISDNHDLC_H__
30 #define __ISDNHDLC_H__
31
32 struct isdnhdlc_vars {
33 int bit_shift;
34 int hdlc_bits1;
35 int data_bits;
36 int ffbit_shift; /* encoding only */
37 int state;
38 int dstpos;
39
40 u16 crc;
41
42 u8 cbin;
43 u8 shift_reg;
44 u8 ffvalue;
45
46 /* set if transferring data */
47 u32 data_received:1;
48 /* set if D channel (send idle instead of flags) */
49 u32 dchannel:1;
50 /* set if 56K adaptation */
51 u32 do_adapt56:1;
52 /* set if in closing phase (need to send CRC + flag) */
53 u32 do_closing:1;
54 /* set if data is bitreverse */
55 u32 do_bitreverse:1;
56 };
57
58 /* Feature Flags */
59 #define HDLC_56KBIT 0x01
60 #define HDLC_DCHANNEL 0x02
61 #define HDLC_BITREVERSE 0x04
62
63 /*
64 The return value from isdnhdlc_decode is
65 the frame length, 0 if no complete frame was decoded,
66 or a negative error number
67 */
68 #define HDLC_FRAMING_ERROR 1
69 #define HDLC_CRC_ERROR 2
70 #define HDLC_LENGTH_ERROR 3
71
72 extern void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, u32 features);
73
74 extern int isdnhdlc_decode(struct isdnhdlc_vars *hdlc, const u8 *src,
75 int slen, int *count, u8 *dst, int dsize);
76
77 extern void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, u32 features);
78
79 extern int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src,
80 u16 slen, int *count, u8 *dst, int dsize);
81
82 #endif /* __ISDNHDLC_H__ */