| /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| /* |
| * hdlc.h -- General purpose ISDN HDLC decoder. |
| * |
| * Implementation of a HDLC decoder/encoder in software. |
| * Necessary because some ISDN devices don't have HDLC |
| * controllers. |
| * |
| * Copyright (C) |
| * 2009 Karsten Keil <keil@b1-systems.de> |
| * 2002 Wolfgang Mües <wolfgang@iksw-muees.de> |
| * 2001 Frode Isaksen <fisaksen@bewan.com> |
| * 2001 Kai Germaschewski <kai.germaschewski@gmx.de> |
| */ |
| |
| #ifndef __ISDNHDLC_H__ |
| #define __ISDNHDLC_H__ |
| |
| struct isdnhdlc_vars { |
| int bit_shift; |
| int hdlc_bits1; |
| int data_bits; |
| int ffbit_shift; /* encoding only */ |
| int state; |
| int dstpos; |
| |
| u16 crc; |
| |
| u8 cbin; |
| u8 shift_reg; |
| u8 ffvalue; |
| |
| /* set if transferring data */ |
| u32 data_received:1; |
| /* set if D channel (send idle instead of flags) */ |
| u32 dchannel:1; |
| /* set if 56K adaptation */ |
| u32 do_adapt56:1; |
| /* set if in closing phase (need to send CRC + flag) */ |
| u32 do_closing:1; |
| /* set if data is bitreverse */ |
| u32 do_bitreverse:1; |
| }; |
| |
| /* Feature Flags */ |
| #define HDLC_56KBIT 0x01 |
| #define HDLC_DCHANNEL 0x02 |
| #define HDLC_BITREVERSE 0x04 |
| |
| /* |
| The return value from isdnhdlc_decode is |
| the frame length, 0 if no complete frame was decoded, |
| or a negative error number |
| */ |
| #define HDLC_FRAMING_ERROR 1 |
| #define HDLC_CRC_ERROR 2 |
| #define HDLC_LENGTH_ERROR 3 |
| |
| extern void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, u32 features); |
| |
| extern int isdnhdlc_decode(struct isdnhdlc_vars *hdlc, const u8 *src, |
| int slen, int *count, u8 *dst, int dsize); |
| |
| extern void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, u32 features); |
| |
| extern int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src, |
| u16 slen, int *count, u8 *dst, int dsize); |
| |
| #endif /* __ISDNHDLC_H__ */ |
