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1/* SPDX-License-Identifier: GPL-2.0-or-later */2/*3 * hdlc.h -- General purpose ISDN HDLC decoder.4 *5 * Implementation of a HDLC decoder/encoder in software.6 * Necessary because some ISDN devices don't have HDLC7 * controllers.8 *9 * Copyright (C)10 * 2009 Karsten Keil <keil@b1-systems.de>11 * 2002 Wolfgang Mües <wolfgang@iksw-muees.de>12 * 2001 Frode Isaksen <fisaksen@bewan.com>13 * 2001 Kai Germaschewski <kai.germaschewski@gmx.de>14 */15 16#ifndef __ISDNHDLC_H__17#define __ISDNHDLC_H__18 19struct isdnhdlc_vars {20 int bit_shift;21 int hdlc_bits1;22 int data_bits;23 int ffbit_shift; /* encoding only */24 int state;25 int dstpos;26 27 u16 crc;28 29 u8 cbin;30 u8 shift_reg;31 u8 ffvalue;32 33 /* set if transferring data */34 u32 data_received:1;35 /* set if D channel (send idle instead of flags) */36 u32 dchannel:1;37 /* set if 56K adaptation */38 u32 do_adapt56:1;39 /* set if in closing phase (need to send CRC + flag) */40 u32 do_closing:1;41 /* set if data is bitreverse */42 u32 do_bitreverse:1;43};44 45/* Feature Flags */46#define HDLC_56KBIT 0x0147#define HDLC_DCHANNEL 0x0248#define HDLC_BITREVERSE 0x0449 50/*51 The return value from isdnhdlc_decode is52 the frame length, 0 if no complete frame was decoded,53 or a negative error number54*/55#define HDLC_FRAMING_ERROR 156#define HDLC_CRC_ERROR 257#define HDLC_LENGTH_ERROR 358 59extern void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, u32 features);60 61extern int isdnhdlc_decode(struct isdnhdlc_vars *hdlc, const u8 *src,62 int slen, int *count, u8 *dst, int dsize);63 64extern void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, u32 features);65 66extern int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src,67 u16 slen, int *count, u8 *dst, int dsize);68 69#endif /* __ISDNHDLC_H__ */70