patch-2.4.21 linux-2.4.21/drivers/isdn/hisax/isdnhdlc.c

• Lines: 670
• Date: 2003-06-13 07:51:34.000000000 -0700
• Orig file: linux-2.4.20/drivers/isdn/hisax/isdnhdlc.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.20/drivers/isdn/hisax/isdnhdlc.c linux-2.4.21/drivers/isdn/hisax/isdnhdlc.c
@@ -0,0 +1,669 @@
+/*
+ * isdnhdlc.c  --  General purpose ISDN HDLC decoder.
+ *
+ *Copyright (C) 2002	Wolfgang Mües      <wolfgang@iksw-muees.de>
+ *		2001 	Frode Isaksen      <fisaksen@bewan.com>
+ *              2001 	Kai Germaschewski  <kai.germaschewski@gmx.de>
+ *
+ *      This program is free software; you can redistribute it and/or modify
+ *      it under the terms of the GNU General Public License as published by
+ *      the Free Software Foundation; either version 2 of the License, or
+ *      (at your option) any later version.
+ *
+ *      This program is distributed in the hope that it will be useful,
+ *      but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *      GNU General Public License for more details.
+ *
+ *      You should have received a copy of the GNU General Public License
+ *      along with this program; if not, write to the Free Software
+ *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include "isdnhdlc.h"
+
+/*-------------------------------------------------------------------*/
+
+MODULE_AUTHOR("Wolfgang Mües <wolfgang@iksw-muees.de>, "
+	      "Frode Isaksen <fisaksen@bewan.com>, "
+	      "Kai Germaschewski <kai.germaschewski@gmx.de>");
+MODULE_DESCRIPTION("General purpose ISDN HDLC decoder");
+MODULE_LICENSE("GPL");
+
+/*-------------------------------------------------------------------*/
+
+/* bit swap table.
+ * Very handy for devices with different bit order,
+ * and neccessary for each transparent B-channel access for all
+ * devices which works with this HDLC decoder without bit reversal.
+ */
+const unsigned char isdnhdlc_bit_rev_tab[256] = {
+	0x00,0x80,0x40,0xC0,0x20,0xA0,0x60,0xE0,0x10,0x90,0x50,0xD0,0x30,0xB0,0x70,0xF0,
+	0x08,0x88,0x48,0xC8,0x28,0xA8,0x68,0xE8,0x18,0x98,0x58,0xD8,0x38,0xB8,0x78,0xF8,
+	0x04,0x84,0x44,0xC4,0x24,0xA4,0x64,0xE4,0x14,0x94,0x54,0xD4,0x34,0xB4,0x74,0xF4,
+	0x0C,0x8C,0x4C,0xCC,0x2C,0xAC,0x6C,0xEC,0x1C,0x9C,0x5C,0xDC,0x3C,0xBC,0x7C,0xFC,
+	0x02,0x82,0x42,0xC2,0x22,0xA2,0x62,0xE2,0x12,0x92,0x52,0xD2,0x32,0xB2,0x72,0xF2,
+	0x0A,0x8A,0x4A,0xCA,0x2A,0xAA,0x6A,0xEA,0x1A,0x9A,0x5A,0xDA,0x3A,0xBA,0x7A,0xFA,
+	0x06,0x86,0x46,0xC6,0x26,0xA6,0x66,0xE6,0x16,0x96,0x56,0xD6,0x36,0xB6,0x76,0xF6,
+	0x0E,0x8E,0x4E,0xCE,0x2E,0xAE,0x6E,0xEE,0x1E,0x9E,0x5E,0xDE,0x3E,0xBE,0x7E,0xFE,
+	0x01,0x81,0x41,0xC1,0x21,0xA1,0x61,0xE1,0x11,0x91,0x51,0xD1,0x31,0xB1,0x71,0xF1,
+	0x09,0x89,0x49,0xC9,0x29,0xA9,0x69,0xE9,0x19,0x99,0x59,0xD9,0x39,0xB9,0x79,0xF9,
+	0x05,0x85,0x45,0xC5,0x25,0xA5,0x65,0xE5,0x15,0x95,0x55,0xD5,0x35,0xB5,0x75,0xF5,
+	0x0D,0x8D,0x4D,0xCD,0x2D,0xAD,0x6D,0xED,0x1D,0x9D,0x5D,0xDD,0x3D,0xBD,0x7D,0xFD,
+	0x03,0x83,0x43,0xC3,0x23,0xA3,0x63,0xE3,0x13,0x93,0x53,0xD3,0x33,0xB3,0x73,0xF3,
+	0x0B,0x8B,0x4B,0xCB,0x2B,0xAB,0x6B,0xEB,0x1B,0x9B,0x5B,0xDB,0x3B,0xBB,0x7B,0xFB,
+	0x07,0x87,0x47,0xC7,0x27,0xA7,0x67,0xE7,0x17,0x97,0x57,0xD7,0x37,0xB7,0x77,0xF7,
+	0x0F,0x8F,0x4F,0xCF,0x2F,0xAF,0x6F,0xEF,0x1F,0x9F,0x5F,0xDF,0x3F,0xBF,0x7F,0xFF
+};
+
+/* Table for CRC16. Internal used only. */
+static const unsigned short int crc16_tab[] = {
+	0x0000,0x1189,0x2312,0x329b,0x4624,0x57ad,0x6536,0x74bf,
+	0x8c48,0x9dc1,0xaf5a,0xbed3,0xca6c,0xdbe5,0xe97e,0xf8f7,
+	0x1081,0x0108,0x3393,0x221a,0x56a5,0x472c,0x75b7,0x643e,
+	0x9cc9,0x8d40,0xbfdb,0xae52,0xdaed,0xcb64,0xf9ff,0xe876,
+	0x2102,0x308b,0x0210,0x1399,0x6726,0x76af,0x4434,0x55bd,
+	0xad4a,0xbcc3,0x8e58,0x9fd1,0xeb6e,0xfae7,0xc87c,0xd9f5,
+	0x3183,0x200a,0x1291,0x0318,0x77a7,0x662e,0x54b5,0x453c,
+	0xbdcb,0xac42,0x9ed9,0x8f50,0xfbef,0xea66,0xd8fd,0xc974,
+	0x4204,0x538d,0x6116,0x709f,0x0420,0x15a9,0x2732,0x36bb,
+	0xce4c,0xdfc5,0xed5e,0xfcd7,0x8868,0x99e1,0xab7a,0xbaf3,
+	0x5285,0x430c,0x7197,0x601e,0x14a1,0x0528,0x37b3,0x263a,
+	0xdecd,0xcf44,0xfddf,0xec56,0x98e9,0x8960,0xbbfb,0xaa72,
+	0x6306,0x728f,0x4014,0x519d,0x2522,0x34ab,0x0630,0x17b9,
+	0xef4e,0xfec7,0xcc5c,0xddd5,0xa96a,0xb8e3,0x8a78,0x9bf1,
+	0x7387,0x620e,0x5095,0x411c,0x35a3,0x242a,0x16b1,0x0738,
+	0xffcf,0xee46,0xdcdd,0xcd54,0xb9eb,0xa862,0x9af9,0x8b70,
+	0x8408,0x9581,0xa71a,0xb693,0xc22c,0xd3a5,0xe13e,0xf0b7,
+	0x0840,0x19c9,0x2b52,0x3adb,0x4e64,0x5fed,0x6d76,0x7cff,
+	0x9489,0x8500,0xb79b,0xa612,0xd2ad,0xc324,0xf1bf,0xe036,
+	0x18c1,0x0948,0x3bd3,0x2a5a,0x5ee5,0x4f6c,0x7df7,0x6c7e,
+	0xa50a,0xb483,0x8618,0x9791,0xe32e,0xf2a7,0xc03c,0xd1b5,
+	0x2942,0x38cb,0x0a50,0x1bd9,0x6f66,0x7eef,0x4c74,0x5dfd,
+	0xb58b,0xa402,0x9699,0x8710,0xf3af,0xe226,0xd0bd,0xc134,
+	0x39c3,0x284a,0x1ad1,0x0b58,0x7fe7,0x6e6e,0x5cf5,0x4d7c,
+	0xc60c,0xd785,0xe51e,0xf497,0x8028,0x91a1,0xa33a,0xb2b3,
+	0x4a44,0x5bcd,0x6956,0x78df,0x0c60,0x1de9,0x2f72,0x3efb,
+	0xd68d,0xc704,0xf59f,0xe416,0x90a9,0x8120,0xb3bb,0xa232,
+	0x5ac5,0x4b4c,0x79d7,0x685e,0x1ce1,0x0d68,0x3ff3,0x2e7a,
+	0xe70e,0xf687,0xc41c,0xd595,0xa12a,0xb0a3,0x8238,0x93b1,
+	0x6b46,0x7acf,0x4854,0x59dd,0x2d62,0x3ceb,0x0e70,0x1ff9,
+	0xf78f,0xe606,0xd49d,0xc514,0xb1ab,0xa022,0x92b9,0x8330,
+	0x7bc7,0x6a4e,0x58d5,0x495c,0x3de3,0x2c6a,0x1ef1,0x0f78
+};
+
+
+enum {
+	HDLC_FAST_IDLE,HDLC_GET_FLAG_B0,HDLC_GETFLAG_B1A6,HDLC_GETFLAG_B7,
+	HDLC_GET_DATA,HDLC_FAST_FLAG
+};
+
+enum {
+	HDLC_SEND_DATA,HDLC_SEND_CRC1,HDLC_SEND_FAST_FLAG,
+	HDLC_SEND_FIRST_FLAG,HDLC_SEND_CRC2,HDLC_SEND_CLOSING_FLAG,
+	HDLC_SEND_IDLE1,HDLC_SEND_FAST_IDLE,HDLC_SENDFLAG_B0,
+	HDLC_SENDFLAG_B1A6,HDLC_SENDFLAG_B7,STOPPED
+};
+
+void isdnhdlc_rcv_init (struct isdnhdlc_vars *hdlc, int do_adapt56)
+{
+   	hdlc->bit_shift = 0;
+	hdlc->hdlc_bits1 = 0;
+	hdlc->data_bits = 0;
+	hdlc->ffbit_shift = 0;
+	hdlc->data_received = 0;
+	hdlc->state = HDLC_GET_DATA;
+	hdlc->do_adapt56 = do_adapt56;
+	hdlc->dchannel = 0;
+	hdlc->crc = 0;
+	hdlc->cbin = 0;
+	hdlc->shift_reg = 0;
+	hdlc->ffvalue = 0;
+	hdlc->dstpos = 0;
+}
+
+void isdnhdlc_out_init (struct isdnhdlc_vars *hdlc, int is_d_channel, int do_adapt56)
+{
+   	hdlc->bit_shift = 0;
+	hdlc->hdlc_bits1 = 0;
+	hdlc->data_bits = 0;
+	hdlc->ffbit_shift = 0;
+	hdlc->data_received = 0;
+	hdlc->do_closing = 0;
+	hdlc->ffvalue = 0;
+	if (is_d_channel) {
+		hdlc->dchannel = 1;
+		hdlc->state = HDLC_SEND_FIRST_FLAG;
+	} else {
+		hdlc->dchannel = 0;
+		hdlc->state = HDLC_SEND_FAST_FLAG;
+		hdlc->ffvalue = 0x7e;
+	}
+	hdlc->cbin = 0x7e;
+	hdlc->bit_shift = 0;
+	if(do_adapt56){
+		hdlc->do_adapt56 = 1;
+		hdlc->data_bits = 0;
+		hdlc->state = HDLC_SENDFLAG_B0;
+	} else {
+		hdlc->do_adapt56 = 0;
+		hdlc->data_bits = 8;
+	}
+	hdlc->shift_reg = 0;
+}
+
+/*
+  isdnhdlc_decode - decodes HDLC frames from a transparent bit stream.
+
+  The source buffer is scanned for valid HDLC frames looking for
+  flags (01111110) to indicate the start of a frame. If the start of
+  the frame is found, the bit stuffing is removed (0 after 5 1's).
+  When a new flag is found, the complete frame has been received
+  and the CRC is checked.
+  If a valid frame is found, the function returns the frame length
+  excluding the CRC with the bit HDLC_END_OF_FRAME set.
+  If the beginning of a valid frame is found, the function returns
+  the length.
+  If a framing error is found (too many 1s and not a flag) the function
+  returns the length with the bit HDLC_FRAMING_ERROR set.
+  If a CRC error is found the function returns the length with the
+  bit HDLC_CRC_ERROR set.
+  If the frame length exceeds the destination buffer size, the function
+  returns the length with the bit HDLC_LENGTH_ERROR set.
+
+  src - source buffer
+  slen - source buffer length
+  count - number of bytes removed (decoded) from the source buffer
+  dst _ destination buffer
+  dsize - destination buffer size
+  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 status=0;
+
+	static const unsigned char fast_flag[]={
+		0x00,0x00,0x00,0x20,0x30,0x38,0x3c,0x3e,0x3f
+	};
+
+	static const unsigned char fast_flag_value[]={
+		0x00,0x7e,0xfc,0xf9,0xf3,0xe7,0xcf,0x9f,0x3f
+	};
+
+	static const unsigned char fast_abort[]={
+		0x00,0x00,0x80,0xc0,0xe0,0xf0,0xf8,0xfc,0xfe,0xff
+	};
+
+	*count = slen;
+
+	while(slen > 0){
+		if(hdlc->bit_shift==0){
+			hdlc->cbin = *src++;
+			slen--;
+			hdlc->bit_shift = 8;
+			if(hdlc->do_adapt56){
+				hdlc->bit_shift --;
+			}
+		}
+
+		switch(hdlc->state){
+		case STOPPED:
+			return 0;
+		case HDLC_FAST_IDLE:
+			if(hdlc->cbin == 0xff){
+				hdlc->bit_shift = 0;
+				break;
+			}
+			hdlc->state = HDLC_GET_FLAG_B0;
+			hdlc->hdlc_bits1 = 0;
+			hdlc->bit_shift = 8;
+			break;
+		case HDLC_GET_FLAG_B0:
+			if(!(hdlc->cbin & 0x80)) {
+				hdlc->state = HDLC_GETFLAG_B1A6;
+				hdlc->hdlc_bits1 = 0;
+			} else {
+				if(!hdlc->do_adapt56){
+					if(++hdlc->hdlc_bits1 >=8 ) if(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){
+					hdlc->state = HDLC_GETFLAG_B7;
+				}
+			} else {
+				hdlc->hdlc_bits1 = 0;
+			}
+			hdlc->cbin<<=1;
+			hdlc->bit_shift --;
+			break;
+		case HDLC_GETFLAG_B7:
+			if(hdlc->cbin & 0x80) {
+				hdlc->state = HDLC_GET_FLAG_B0;
+			} else {
+				hdlc->state = HDLC_GET_DATA;
+				hdlc->crc = 0xffff;
+				hdlc->shift_reg = 0;
+				hdlc->hdlc_bits1 = 0;
+				hdlc->data_bits = 0;
+				hdlc->data_received = 0;
+			}
+			hdlc->cbin<<=1;
+			hdlc->bit_shift --;
+			break;
+		case HDLC_GET_DATA:
+			if(hdlc->cbin & 0x80){
+				hdlc->hdlc_bits1++;
+				switch(hdlc->hdlc_bits1){
+				case 6:
+					break;
+				case 7:
+					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;
+							hdlc->bit_shift=1;
+							break;
+						}
+					} else {
+						hdlc->state = HDLC_GET_FLAG_B0;
+					}
+					break;
+				default:
+					hdlc->shift_reg>>=1;
+					hdlc->shift_reg |= 0x80;
+					hdlc->data_bits++;
+					break;
+				}
+			} else {
+				switch(hdlc->hdlc_bits1){
+				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;
+						}
+					}
+					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 {
+						hdlc->state = HDLC_GET_DATA;
+						hdlc->data_received = 0;
+					}
+					break;
+				default:
+					hdlc->shift_reg>>=1;
+					hdlc->data_bits++;
+					break;
+				}
+				hdlc->hdlc_bits1 = 0;
+			}
+			if (status) {
+				hdlc->dstpos = 0;
+				*count -= slen;
+				hdlc->cbin <<= 1;
+				hdlc->bit_shift--;
+				return status;
+			}
+			if(hdlc->data_bits==8){
+				unsigned cval;
+
+				hdlc->data_bits = 0;
+				hdlc->data_received = 1;
+				cval = (hdlc->crc^hdlc->shift_reg) & 0xff;
+				hdlc->crc = (hdlc->crc>>8)^crc16_tab[cval];
+				// good byte received
+				if (dsize--) {
+					dst[hdlc->dstpos++] = hdlc->shift_reg;
+				} else {
+					// frame too long
+					status = -HDLC_LENGTH_ERROR;
+					hdlc->dstpos = 0;
+				}
+			}
+			hdlc->cbin <<= 1;
+			hdlc->bit_shift--;
+			break;
+		case HDLC_FAST_FLAG:
+			if(hdlc->cbin==hdlc->ffvalue){
+				hdlc->bit_shift = 0;
+				break;
+			} else {
+				if(hdlc->cbin == 0xff){
+					hdlc->state = HDLC_FAST_IDLE;
+					hdlc->bit_shift=0;
+				} 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;
+				}
+			}
+			break;
+		default:
+			break;
+		}
+	}
+	*count -= slen;
+	return 0;
+}
+
+/*
+  isdnhdlc_encode - encodes HDLC frames to a transparent bit stream.
+
+  The bit stream starts with a beginning flag (01111110). After
+  that each byte is added to the bit stream with bit stuffing added
+  (0 after 5 1's).
+  When the last byte has been removed from the source buffer, the
+  CRC (2 bytes is added) and the frame terminates with the ending flag.
+  For the dchannel, the idle character (all 1's) is also added at the end.
+  If this function is called with empty source buffer (slen=0), flags or
+  idle character will be generated.
+
+  src - source buffer
+  slen - source buffer length
+  count - number of bytes removed (encoded) from source buffer
+  dst _ destination buffer
+  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)
+{
+	static const unsigned char xfast_flag_value[] = {
+		0x7e,0x3f,0x9f,0xcf,0xe7,0xf3,0xf9,0xfc,0x7e
+	};
+
+	int len = 0;
+
+	*count = slen;
+
+	while (dsize > 0) {
+		if(hdlc->bit_shift==0){
+			if(slen && !hdlc->do_closing){
+				hdlc->shift_reg = *src++;
+				slen--;
+				if (slen == 0)
+					hdlc->do_closing = 1;  /* closing sequence, CRC + flag(s) */
+				hdlc->bit_shift = 8;
+			} else {
+				if(hdlc->state == HDLC_SEND_DATA){
+					if(hdlc->data_received){
+						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;
+					}
+				}
+
+			}
+		}
+
+		switch(hdlc->state){
+		case STOPPED:
+			while (dsize--)
+				*dst++ = 0xff;
+
+			return dsize;
+		case HDLC_SEND_FAST_FLAG:
+			hdlc->do_closing = 0;
+			if(slen == 0){
+				*dst++ = hdlc->ffvalue;
+				len++;
+				dsize--;
+				break;
+			}
+			if(hdlc->bit_shift==8){
+				hdlc->cbin = hdlc->ffvalue>>(8-hdlc->data_bits);
+				hdlc->state = HDLC_SEND_DATA;
+				hdlc->crc = 0xffff;
+				hdlc->hdlc_bits1 = 0;
+				hdlc->data_received = 1;
+			}
+			break;
+		case HDLC_SENDFLAG_B0:
+			hdlc->do_closing = 0;
+			hdlc->cbin <<= 1;
+			hdlc->data_bits++;
+			hdlc->hdlc_bits1 = 0;
+			hdlc->state = HDLC_SENDFLAG_B1A6;
+			break;
+		case HDLC_SENDFLAG_B1A6:
+			hdlc->cbin <<= 1;
+			hdlc->data_bits++;
+			hdlc->cbin++;
+			if(++hdlc->hdlc_bits1 == 6)
+				hdlc->state = HDLC_SENDFLAG_B7;
+			break;
+		case HDLC_SENDFLAG_B7:
+			hdlc->cbin <<= 1;
+			hdlc->data_bits++;
+			if(slen == 0){
+				hdlc->state = HDLC_SENDFLAG_B0;
+				break;
+			}
+			if(hdlc->bit_shift==8){
+				hdlc->state = HDLC_SEND_DATA;
+				hdlc->crc = 0xffff;
+				hdlc->hdlc_bits1 = 0;
+				hdlc->data_received = 1;
+			}
+			break;
+		case HDLC_SEND_FIRST_FLAG:
+			hdlc->data_received = 1;
+			if(hdlc->data_bits==8){
+				hdlc->state = HDLC_SEND_DATA;
+				hdlc->crc = 0xffff;
+				hdlc->hdlc_bits1 = 0;
+				break;
+			}
+			hdlc->cbin <<= 1;
+			hdlc->data_bits++;
+			if(hdlc->shift_reg & 0x01)
+				hdlc->cbin++;
+			hdlc->shift_reg >>= 1;
+			hdlc->bit_shift--;
+			if(hdlc->bit_shift==0){
+				hdlc->state = HDLC_SEND_DATA;
+				hdlc->crc = 0xffff;
+				hdlc->hdlc_bits1 = 0;
+			}
+			break;
+		case HDLC_SEND_DATA:
+			hdlc->cbin <<= 1;
+			hdlc->data_bits++;
+			if(hdlc->hdlc_bits1 == 5){
+				hdlc->hdlc_bits1 = 0;
+				break;
+			}
+			if(hdlc->bit_shift==8){
+				unsigned cval;
+
+				cval = (hdlc->crc^hdlc->shift_reg) & 0xff;
+				hdlc->crc = (hdlc->crc>>8)^crc16_tab[cval];
+			}
+			if(hdlc->shift_reg & 0x01){
+				hdlc->hdlc_bits1++;
+				hdlc->cbin++;
+				hdlc->shift_reg >>= 1;
+				hdlc->bit_shift--;
+			} else {
+				hdlc->hdlc_bits1 = 0;
+				hdlc->shift_reg >>= 1;
+				hdlc->bit_shift--;
+			}
+			break;
+		case HDLC_SEND_CRC1:
+			hdlc->cbin <<= 1;
+			hdlc->data_bits++;
+			if(hdlc->hdlc_bits1 == 5){
+				hdlc->hdlc_bits1 = 0;
+				break;
+			}
+			if(hdlc->shift_reg & 0x01){
+				hdlc->hdlc_bits1++;
+				hdlc->cbin++;
+				hdlc->shift_reg >>= 1;
+				hdlc->bit_shift--;
+			} else {
+				hdlc->hdlc_bits1 = 0;
+				hdlc->shift_reg >>= 1;
+				hdlc->bit_shift--;
+			}
+			if(hdlc->bit_shift==0){
+				hdlc->shift_reg = (hdlc->crc >> 8);
+				hdlc->state = HDLC_SEND_CRC2;
+				hdlc->bit_shift = 8;
+			}
+			break;
+		case HDLC_SEND_CRC2:
+			hdlc->cbin <<= 1;
+			hdlc->data_bits++;
+			if(hdlc->hdlc_bits1 == 5){
+				hdlc->hdlc_bits1 = 0;
+				break;
+			}
+			if(hdlc->shift_reg & 0x01){
+				hdlc->hdlc_bits1++;
+				hdlc->cbin++;
+				hdlc->shift_reg >>= 1;
+				hdlc->bit_shift--;
+			} else {
+				hdlc->hdlc_bits1 = 0;
+				hdlc->shift_reg >>= 1;
+				hdlc->bit_shift--;
+			}
+			if(hdlc->bit_shift==0){
+				hdlc->shift_reg = 0x7e;
+				hdlc->state = HDLC_SEND_CLOSING_FLAG;
+				hdlc->bit_shift = 8;
+			}
+			break;
+		case HDLC_SEND_CLOSING_FLAG:
+			hdlc->cbin <<= 1;
+			hdlc->data_bits++;
+			if(hdlc->hdlc_bits1 == 5){
+				hdlc->hdlc_bits1 = 0;
+				break;
+			}
+			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];
+				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;
+				} else {
+					if(!hdlc->do_adapt56){
+						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;
+				}
+			}
+			break;
+		case HDLC_SEND_IDLE1:
+			hdlc->do_closing = 0;
+			hdlc->cbin <<= 1;
+			hdlc->cbin++;
+			hdlc->data_bits++;
+			hdlc->bit_shift--;
+			if(hdlc->bit_shift==0){
+				hdlc->state = HDLC_SEND_FAST_IDLE;
+				hdlc->bit_shift = 0;
+			}
+			break;
+		case HDLC_SEND_FAST_IDLE:
+			hdlc->do_closing = 0;
+			hdlc->cbin = 0xff;
+			hdlc->data_bits = 8;
+			if(hdlc->bit_shift == 8){
+				hdlc->cbin = 0x7e;
+				hdlc->state = HDLC_SEND_FIRST_FLAG;
+			} else {
+				*dst++ = hdlc->cbin;
+				hdlc->bit_shift = hdlc->data_bits = 0;
+				len++;
+				dsize = 0;
+			}
+			break;
+		default:
+			break;
+		}
+		if(hdlc->do_adapt56){
+			if(hdlc->data_bits==7){
+				hdlc->cbin <<= 1;
+				hdlc->cbin++;
+				hdlc->data_bits++;
+			}
+		}
+		if(hdlc->data_bits==8){
+			*dst++ = hdlc->cbin;
+			hdlc->data_bits = 0;
+			len++;
+			dsize--;
+		}
+	}
+	*count -= slen;
+
+	return len;
+}
+
+EXPORT_SYMBOL(isdnhdlc_bit_rev_tab);
+EXPORT_SYMBOL(isdnhdlc_rcv_init);
+EXPORT_SYMBOL(isdnhdlc_decode);
+EXPORT_SYMBOL(isdnhdlc_out_init);
+EXPORT_SYMBOL(isdnhdlc_encode);