| 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 HDLC |
|---|
| 7 | * 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 | |
|---|
| 19 | struct 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 0x01 |
|---|
| 47 | #define HDLC_DCHANNEL 0x02 |
|---|
| 48 | #define HDLC_BITREVERSE 0x04 |
|---|
| 49 | |
|---|
| 50 | /* |
|---|
| 51 | The return value from isdnhdlc_decode is |
|---|
| 52 | the frame length, 0 if no complete frame was decoded, |
|---|
| 53 | or a negative error number |
|---|
| 54 | */ |
|---|
| 55 | #define HDLC_FRAMING_ERROR 1 |
|---|
| 56 | #define HDLC_CRC_ERROR 2 |
|---|
| 57 | #define HDLC_LENGTH_ERROR 3 |
|---|
| 58 | |
|---|
| 59 | extern void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, u32 features); |
|---|
| 60 | |
|---|
| 61 | extern int isdnhdlc_decode(struct isdnhdlc_vars *hdlc, const u8 *src, |
|---|
| 62 | int slen, int *count, u8 *dst, int dsize); |
|---|
| 63 | |
|---|
| 64 | extern void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, u32 features); |
|---|
| 65 | |
|---|
| 66 | extern 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 | |
|---|
