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69 lines
1.7 KiB
69 lines
1.7 KiB
/* SPDX-License-Identifier: GPL-2.0-or-later */ |
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/* |
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* hdlc.h -- General purpose ISDN HDLC decoder. |
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* |
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* Implementation of a HDLC decoder/encoder in software. |
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* Necessary because some ISDN devices don't have HDLC |
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* controllers. |
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* |
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* Copyright (C) |
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* 2009 Karsten Keil <[email protected]> |
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* 2002 Wolfgang Mües <[email protected]> |
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* 2001 Frode Isaksen <[email protected]> |
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* 2001 Kai Germaschewski <[email protected]> |
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*/ |
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#ifndef __ISDNHDLC_H__ |
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#define __ISDNHDLC_H__ |
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struct isdnhdlc_vars { |
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int bit_shift; |
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int hdlc_bits1; |
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int data_bits; |
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int ffbit_shift; /* encoding only */ |
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int state; |
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int dstpos; |
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u16 crc; |
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u8 cbin; |
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u8 shift_reg; |
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u8 ffvalue; |
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/* set if transferring data */ |
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u32 data_received:1; |
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/* set if D channel (send idle instead of flags) */ |
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u32 dchannel:1; |
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/* set if 56K adaptation */ |
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u32 do_adapt56:1; |
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/* set if in closing phase (need to send CRC + flag) */ |
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u32 do_closing:1; |
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/* set if data is bitreverse */ |
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u32 do_bitreverse:1; |
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}; |
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/* Feature Flags */ |
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#define HDLC_56KBIT 0x01 |
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#define HDLC_DCHANNEL 0x02 |
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#define HDLC_BITREVERSE 0x04 |
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/* |
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The return value from isdnhdlc_decode is |
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the frame length, 0 if no complete frame was decoded, |
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or a negative error number |
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*/ |
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#define HDLC_FRAMING_ERROR 1 |
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#define HDLC_CRC_ERROR 2 |
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#define HDLC_LENGTH_ERROR 3 |
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extern void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, u32 features); |
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extern int isdnhdlc_decode(struct isdnhdlc_vars *hdlc, const u8 *src, |
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int slen, int *count, u8 *dst, int dsize); |
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extern void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, u32 features); |
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extern int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src, |
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u16 slen, int *count, u8 *dst, int dsize); |
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#endif /* __ISDNHDLC_H__ */
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