Commit 6bd4bcd3 authored by Karsten Keil's avatar Karsten Keil
Browse files

ISDN: Clean up isdnhdlc code 



Clean up isdnhdlc to meet current code standard.
Remove hint to already removed bit reversal table.

Signed-off-by: default avatarKarsten Keil <keil@b1-systems.de>
parent cb3824ba

drivers/isdn/i4l/isdnhdlc.c

+194 −172
Original line number Diff line number Diff line 
/*

 * isdnhdlc.c  --  General purpose ISDN HDLC decoder.

 *

 *Copyright (C) 2002	Wolfgang Mües      <wolfgang@iksw-muees.de>

 * Copyright (C)

 *	2002	Wolfgang Mües		<wolfgang@iksw-muees.de>

 *	2001	Frode Isaksen		<fisaksen@bewan.com>

 *      2001	Kai Germaschewski	<kai.germaschewski@gmx.de>

 *
@@ -63,8 +64,10 @@ void isdnhdlc_rcv_init (struct isdnhdlc_vars *hdlc, int do_adapt56) 
	hdlc->ffvalue = 0;

	hdlc->dstpos = 0;

}

EXPORT_SYMBOL(isdnhdlc_out_init);



void isdnhdlc_out_init (struct isdnhdlc_vars *hdlc, int is_d_channel, int do_adapt56)

void isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, int is_d_channel,

	int do_adapt56)

{

	hdlc->bit_shift = 0;

	hdlc->hdlc_bits1 = 0;
@@ -93,6 +96,25 @@ void isdnhdlc_out_init (struct isdnhdlc_vars *hdlc, int is_d_channel, int do_ada 
	}

	hdlc->shift_reg = 0;

}

EXPORT_SYMBOL(isdnhdlc_rcv_init);



static int

check_frame(struct isdnhdlc_vars *hdlc)

{

	int status;



	if (hdlc->dstpos < 2) 	/* too small - framing error */

		status = -HDLC_FRAMING_ERROR;

	else if (hdlc->crc != 0xf0b8)	/* crc error */

		status = -HDLC_CRC_ERROR;

	else {

		/* remove CRC */

		hdlc->dstpos -= 2;

		/* good frame */

		status = hdlc->dstpos;

	}

	return status;

}



/*

  isdnhdlc_decode - decodes HDLC frames from a transparent bit stream.
@@ -121,8 +143,8 @@ void isdnhdlc_out_init (struct isdnhdlc_vars *hdlc, int is_d_channel, int do_ada 
  returns - number of decoded bytes in the destination buffer and status

  flag.

 */

int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src,

		     int slen, int *count, unsigned char *dst, int dsize)

int isdnhdlc_decode(struct isdnhdlc_vars *hdlc, const u8 *src, int slen,

	int *count, u8 *dst, int dsize)

{

	int status = 0;
@@ -138,6 +160,30 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, 
		0x00, 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff

	};



#define handle_fast_flag(h) \

	do {\

		if (h->cbin == fast_flag[h->bit_shift]) {\

			h->ffvalue = fast_flag_value[h->bit_shift];\

			h->state = HDLC_FAST_FLAG;\

			h->ffbit_shift = h->bit_shift;\

			h->bit_shift = 1;\

		} else {\

			h->state = HDLC_GET_DATA;\

			h->data_received = 0;\

		} \

	} while (0)



#define handle_abort(h) \

	do {\

		h->shift_reg = fast_abort[h->ffbit_shift - 1];\

		h->hdlc_bits1 = h->ffbit_shift - 2;\

		if (h->hdlc_bits1 < 0)\

			h->hdlc_bits1 = 0;\

		h->data_bits = h->ffbit_shift - 1;\

		h->state = HDLC_GET_DATA;\

		h->data_received = 0;\

	} while (0)



	*count = slen;



	while (slen > 0) {
@@ -145,10 +191,9 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, 
			hdlc->cbin = *src++;

			slen--;

			hdlc->bit_shift = 8;

			if(hdlc->do_adapt56){

			if (hdlc->do_adapt56)

				hdlc->bit_shift--;

		}

		}



		switch (hdlc->state) {

		case STOPPED:
@@ -167,23 +212,21 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, 
				hdlc->state = HDLC_GETFLAG_B1A6;

				hdlc->hdlc_bits1 = 0;

			} else {

				if(!hdlc->do_adapt56){

					if(++hdlc->hdlc_bits1 >=8 ) if(hdlc->bit_shift==1)

				if ((!hdlc->do_adapt56) &&

				    (++hdlc->hdlc_bits1 >= 8) &&

				    (hdlc->bit_shift == 1))

						hdlc->state = HDLC_FAST_IDLE;

			}

			}

			hdlc->cbin <<= 1;

			hdlc->bit_shift--;

			break;

		case HDLC_GETFLAG_B1A6:

			if (hdlc->cbin & 0x80) {

				hdlc->hdlc_bits1++;

				if(hdlc->hdlc_bits1==6){

				if (hdlc->hdlc_bits1 == 6)

					hdlc->state = HDLC_GETFLAG_B7;

				}

			} else {

			} else

				hdlc->hdlc_bits1 = 0;

			}

			hdlc->cbin <<= 1;

			hdlc->bit_shift--;

			break;
@@ -208,19 +251,19 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, 
				case 6:

					break;

				case 7:

					if(hdlc->data_received) {

						// bad frame

					if (hdlc->data_received)

						/* bad frame */

						status = -HDLC_FRAMING_ERROR;

					}

					if (!hdlc->do_adapt56) {

						if(hdlc->cbin==fast_abort[hdlc->bit_shift+1]){

							hdlc->state = HDLC_FAST_IDLE;

						if (hdlc->cbin == fast_abort

						    [hdlc->bit_shift + 1]) {

							hdlc->state =

								HDLC_FAST_IDLE;

							hdlc->bit_shift = 1;

							break;

						}

					} else {

					} else

						hdlc->state = HDLC_GET_FLAG_B0;

					}

					break;

				default:

					hdlc->shift_reg >>= 1;
@@ -233,33 +276,14 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, 
				case 5:

					break;

				case 6:

					if(hdlc->data_received){

						if (hdlc->dstpos < 2) {

							status = -HDLC_FRAMING_ERROR;

						} else if (hdlc->crc != 0xf0b8){

							// crc error

							status = -HDLC_CRC_ERROR;

						} else {

							// remove CRC

							hdlc->dstpos -= 2;

							// good frame

							status = hdlc->dstpos;

						}

					}

					if (hdlc->data_received)

						status = check_frame(hdlc);

					hdlc->crc = 0xffff;

					hdlc->shift_reg = 0;

					hdlc->data_bits = 0;

					if(!hdlc->do_adapt56){

						if(hdlc->cbin==fast_flag[hdlc->bit_shift]){

							hdlc->ffvalue = fast_flag_value[hdlc->bit_shift];

							hdlc->state = HDLC_FAST_FLAG;

							hdlc->ffbit_shift = hdlc->bit_shift;

							hdlc->bit_shift = 1;

						} else {

							hdlc->state = HDLC_GET_DATA;

							hdlc->data_received = 0;

						}

					} else {

					if (!hdlc->do_adapt56)

						handle_fast_flag(hdlc);

					else {

						hdlc->state = HDLC_GET_DATA;

						hdlc->data_received = 0;

					}
@@ -281,13 +305,14 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, 
			if (hdlc->data_bits == 8) {

				hdlc->data_bits = 0;

				hdlc->data_received = 1;

				hdlc->crc = crc_ccitt_byte(hdlc->crc, hdlc->shift_reg);

				hdlc->crc = crc_ccitt_byte(hdlc->crc,

						hdlc->shift_reg);



				// good byte received

				if (hdlc->dstpos < dsize) {

				/* good byte received */

				if (hdlc->dstpos < dsize)

					dst[hdlc->dstpos++] = hdlc->shift_reg;

				} else {

					// frame too long

				else {

					/* frame too long */

					status = -HDLC_LENGTH_ERROR;

					hdlc->dstpos = 0;

				}
@@ -306,14 +331,8 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, 
				} else if (hdlc->ffbit_shift == 8) {

					hdlc->state = HDLC_GETFLAG_B7;

					break;

				} else {

					hdlc->shift_reg = fast_abort[hdlc->ffbit_shift-1];

					hdlc->hdlc_bits1 = hdlc->ffbit_shift-2;

					if(hdlc->hdlc_bits1<0)hdlc->hdlc_bits1 = 0;

					hdlc->data_bits = hdlc->ffbit_shift-1;

					hdlc->state = HDLC_GET_DATA;

					hdlc->data_received = 0;

				}

				} else

					handle_abort(hdlc);

			}

			break;

		default:
@@ -323,7 +342,7 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, 
	*count -= slen;

	return 0;

}



EXPORT_SYMBOL(isdnhdlc_decode);

/*

  isdnhdlc_encode - encodes HDLC frames to a transparent bit stream.
@@ -343,9 +362,8 @@ int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, 
  dsize - destination buffer size

  returns - number of encoded bytes in the destination buffer

*/

int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src,

		unsigned short slen, int *count,

		unsigned char *dst, int dsize)

int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src, u16 slen,

	int *count, u8 *dst, int dsize)

{

	static const unsigned char xfast_flag_value[] = {

		0x7e, 0x3f, 0x9f, 0xcf, 0xe7, 0xf3, 0xf9, 0xfc, 0x7e
@@ -361,7 +379,8 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src, 
				hdlc->shift_reg = *src++;

				slen--;

				if (slen == 0)

					hdlc->do_closing = 1;  /* closing sequence, CRC + flag(s) */

					/* closing sequence, CRC + flag(s) */

					hdlc->do_closing = 1;

				hdlc->bit_shift = 8;

			} else {

				if (hdlc->state == HDLC_SEND_DATA) {
@@ -369,12 +388,14 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src, 
						hdlc->state = HDLC_SEND_CRC1;

						hdlc->crc ^= 0xffff;

						hdlc->bit_shift = 8;

						hdlc->shift_reg = hdlc->crc & 0xff;

					} else if(!hdlc->do_adapt56){

						hdlc->state = HDLC_SEND_FAST_FLAG;

					} else {

						hdlc->state = HDLC_SENDFLAG_B0;

					}

						hdlc->shift_reg =

							hdlc->crc & 0xff;

					} else if (!hdlc->do_adapt56)

						hdlc->state =

							HDLC_SEND_FAST_FLAG;

					else

						hdlc->state =

							HDLC_SENDFLAG_B0;

				}



			}
@@ -395,7 +416,8 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src, 
				break;

			}

			if (hdlc->bit_shift == 8) {

				hdlc->cbin = hdlc->ffvalue>>(8-hdlc->data_bits);

				hdlc->cbin = hdlc->ffvalue >>

					(8 - hdlc->data_bits);

				hdlc->state = HDLC_SEND_DATA;

				hdlc->crc = 0xffff;

				hdlc->hdlc_bits1 = 0;
@@ -457,9 +479,9 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src, 
				hdlc->hdlc_bits1 = 0;

				break;

			}

			if(hdlc->bit_shift==8){

				hdlc->crc = crc_ccitt_byte(hdlc->crc, hdlc->shift_reg);

			}

			if (hdlc->bit_shift == 8)

				hdlc->crc = crc_ccitt_byte(hdlc->crc,

					hdlc->shift_reg);

			if (hdlc->shift_reg & 0x01) {

				hdlc->hdlc_bits1++;

				hdlc->cbin++;
@@ -524,29 +546,32 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src, 
				hdlc->hdlc_bits1 = 0;

				break;

			}

			if(hdlc->shift_reg & 0x01){

			if (hdlc->shift_reg & 0x01)

				hdlc->cbin++;

			}

			hdlc->shift_reg >>= 1;

			hdlc->bit_shift--;

			if (hdlc->bit_shift == 0) {

				hdlc->ffvalue = xfast_flag_value[hdlc->data_bits];

				hdlc->ffvalue =

					xfast_flag_value[hdlc->data_bits];

				if (hdlc->dchannel) {

					hdlc->ffvalue = 0x7e;

					hdlc->state = HDLC_SEND_IDLE1;

					hdlc->bit_shift = 8-hdlc->data_bits;

					if (hdlc->bit_shift == 0)

						hdlc->state = HDLC_SEND_FAST_IDLE;

						hdlc->state =

							HDLC_SEND_FAST_IDLE;

				} else {

					if (!hdlc->do_adapt56) {

						hdlc->state = HDLC_SEND_FAST_FLAG;

						hdlc->state =

							HDLC_SEND_FAST_FLAG;

						hdlc->data_received = 0;

					} else {

						hdlc->state = HDLC_SENDFLAG_B0;

						hdlc->data_received = 0;

					}

					// Finished with this frame, send flags

					if (dsize > 1) dsize = 1;

					/* Finished this frame, send flags */

					if (dsize > 1)

						dsize = 1;

				}

			}

			break;
@@ -570,7 +595,8 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src, 
				hdlc->state = HDLC_SEND_FIRST_FLAG;

			} else {

				*dst++ = hdlc->cbin;

				hdlc->bit_shift = hdlc->data_bits = 0;

				hdlc->bit_shift = 0;

				hdlc->data_bits = 0;

				len++;

				dsize = 0;

			}
@@ -596,8 +622,4 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const unsigned char *src, 


	return len;

}



EXPORT_SYMBOL(isdnhdlc_rcv_init);

EXPORT_SYMBOL(isdnhdlc_decode);

EXPORT_SYMBOL(isdnhdlc_out_init);

EXPORT_SYMBOL(isdnhdlc_encode);

include/linux/isdn/hdlc.h

+37 −31
Original line number Diff line number Diff line 
/*

 * isdnhdlc.h  --  General purpose ISDN HDLC decoder.

 * hdlc.h  --  General purpose ISDN HDLC decoder.

 *

 * Implementation of a HDLC decoder/encoder in software.

 * Neccessary because some ISDN devices don't have HDLC

 * controllers. Also included: a bit reversal table.

 * controllers.

 *

 *Copyright (C) 2002    Wolfgang Mües      <wolfgang@iksw-muees.de>

 * Copyright (C)

 *	2002	Wolfgang Mües		<wolfgang@iksw-muees.de>

 *	2001	Frode Isaksen		<fisaksen@bewan.com>

 *	2001	Kai Germaschewski	<kai.germaschewski@gmx.de>

 *
@@ -31,20 +32,24 @@ struct isdnhdlc_vars { 
	int bit_shift;

	int hdlc_bits1;

	int data_bits;

	int ffbit_shift; 	// encoding only

	int ffbit_shift;	/* encoding only */

	int state;

	int dstpos;



	unsigned short crc;

	u16 crc;



	unsigned char cbin;

	unsigned char shift_reg;

	unsigned char ffvalue;

	u8 cbin;

	u8 shift_reg;

	u8 ffvalue;



	unsigned int data_received:1; 	// set if transferring data

	unsigned int dchannel:1; 	// set if D channel (send idle instead of flags)

	unsigned int do_adapt56:1; 	// set if 56K adaptation

	unsigned int do_closing:1; 	// set if in closing phase (need to send CRC + flag

	/* 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;

};
@@ -59,12 +64,13 @@ struct isdnhdlc_vars { 


extern void	isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, int do_adapt56);



extern int isdnhdlc_decode (struct isdnhdlc_vars *hdlc, const unsigned char *src, int slen,int *count,

	                    unsigned char *dst, int dsize);

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,int is_d_channel,int do_adapt56);

extern void	isdnhdlc_out_init(struct isdnhdlc_vars *hdlc, int is_d_channel,

			int do_adapt56);



extern int isdnhdlc_encode (struct isdnhdlc_vars *hdlc,const unsigned char *src,unsigned short slen,int *count,

	                    unsigned char *dst,int dsize);

extern int	isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src,

			u16 slen, int *count, u8 *dst, int dsize);



#endif /* __ISDNHDLC_H__ */