patch-2.4.6 linux/drivers/isdn/tpam/tpam_crcpc.c

• Lines: 208
• Date: Mon Jul 2 14:07:55 2001
• Orig file: v2.4.5/linux/drivers/isdn/tpam/tpam_crcpc.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.5/linux/drivers/isdn/tpam/tpam_crcpc.c linux/drivers/isdn/tpam/tpam_crcpc.c
@@ -0,0 +1,207 @@
+/* $Id: tpam_crcpc.c,v 1.1.2.1 2001/06/05 19:45:37 kai Exp $
+ *
+ * Turbo PAM ISDN driver for Linux. (Kernel Driver - CRC encoding)
+ *
+ * Copyright 1998-2000 AUVERTECH Télécom
+ * Copyright 2001 Stelian Pop <stelian.pop@fr.alcove.com>, Alcôve
+ *
+ * For all support questions please contact: <support@auvertech.fr>
+ *
+ * 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, 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.
+ *
+ */
+
+/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+Module Name:
+
+    crcpc.c
+
+Abstract:
+
+    Modem HDLC coding
+    Software HDLC coding / decoding
+
+Revision History:
+
+---------------------------------------------------------------------------*/
+
+#include "tpam.h"
+
+#define  HDLC_CTRL_CHAR_CMPL_MASK	0x20	/* HDLC control character complement mask */
+#define  HDLC_FLAG			0x7E	/* HDLC flag */
+#define  HDLC_CTRL_ESC			0x7D	/* HDLC control escapr character */
+#define  HDLC_LIKE_FCS_INIT_VAL		0xFFFF	/* FCS initial value (0xFFFF for new equipment or 0) */
+#define  HDLC_FCS_OK			0xF0B8	/* This value is the only valid value of FCS */
+
+#define TRUE	1
+#define FALSE	0
+
+static u16 t_ap_hdlc_like_fcs [256] = {
+	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
+};
+
+static u8 ap_t_ctrl_char_complemented[256]; /* list of characters to complement */
+
+static void ap_hdlc_like_ctrl_char_list (u32 ctrl_char) {
+	int i;
+
+	for (i = 0; i < 256; ++i)
+		ap_t_ctrl_char_complemented[i] = FALSE;
+	for (i = 0; i < 32; ++i)
+		if ((ctrl_char >> i) & 0x0001)
+			ap_t_ctrl_char_complemented [i] = TRUE;
+	ap_t_ctrl_char_complemented[HDLC_FLAG] = TRUE;
+	ap_t_ctrl_char_complemented[HDLC_CTRL_ESC] = TRUE;
+		
+}
+
+void init_CRC() {
+	ap_hdlc_like_ctrl_char_list(0xffffffff);
+}
+
+void hdlc_encode_modem(u8 *buffer_in, u32 lng_in,
+		       u8 *buffer_out, u32 *lng_out) {
+	u16 fcs;
+	register u8 data;
+	register u8 *p_data_out = buffer_out;
+
+	fcs = HDLC_LIKE_FCS_INIT_VAL;
+
+	/*
+	 *   Insert HDLC flag at the beginning of the frame
+	 */
+	*p_data_out++ = HDLC_FLAG;
+
+#define ESCAPE_CHAR(data_out, data) \
+	if (ap_t_ctrl_char_complemented[data]) { \
+		*data_out++ = HDLC_CTRL_ESC; \
+		*data_out++ = data ^ 0x20; \
+	} \
+	else \
+		*data_out++ = data;
+
+	while (lng_in--) {
+		data = *buffer_in++;
+
+		/*
+		 *   FCS calculation
+		 */
+		fcs = (fcs>>8) ^ t_ap_hdlc_like_fcs[((u8)(fcs^data)) & 0xff];
+
+		ESCAPE_CHAR(p_data_out, data);
+	}
+
+	/*
+	 *  Add FCS and closing flag
+	 */
+	fcs ^= 0xFFFF;  // Complement
+
+	data = (u8)(fcs & 0xff);	/* LSB */
+	ESCAPE_CHAR(p_data_out, data);
+
+	data = (u8)((fcs >> 8));	/* MSB */
+	ESCAPE_CHAR(p_data_out, data);
+#undef ESCAPE_CHAR
+
+	*p_data_out++ = HDLC_FLAG;
+
+	*lng_out = (u32)(p_data_out - buffer_out);
+}
+
+void hdlc_no_accm_encode(u8 *buffer_in, u32 lng_in, 
+			 u8 *buffer_out, u32 *lng_out) {
+	u16 fcs;
+	register u8 data;
+	register u8 *p_data_out = buffer_out;
+
+	/*
+	 *   Insert HDLC flag at the beginning of the frame
+	 */
+	fcs = HDLC_LIKE_FCS_INIT_VAL;
+
+	while (lng_in--) {
+		data = *buffer_in++;
+		/* calculate FCS */
+		fcs = (fcs>>8) ^ t_ap_hdlc_like_fcs[((u8)(fcs^data)) & 0xff];
+		*p_data_out++ = data;
+	}
+
+	/*
+	 *  Add FCS and closing flag
+	 */
+	fcs ^= 0xFFFF;  // Complement
+	data = (u8)(fcs);    
+	*p_data_out++ = data;
+
+	data =(u8)((fcs >> 8));   // revense MSB / LSB
+	*p_data_out++ = data;
+ 
+	*lng_out = (u32)(p_data_out - buffer_out);
+}
+
+u32 hdlc_no_accm_decode(u8 *buffer_in, u32 lng_in) {
+	u16 fcs;
+	u32 lng = lng_in;
+	register u8 data;
+
+	/*
+	 *   Insert HDLC flag at the beginning of the frame
+	 */
+	fcs = HDLC_LIKE_FCS_INIT_VAL;
+
+	while (lng_in--) {
+		data = *buffer_in++;
+		/* calculate FCS */
+		fcs = (fcs>>8) ^ t_ap_hdlc_like_fcs[((u8)(fcs^data)) & 0xff];
+	}
+
+	if (fcs == HDLC_FCS_OK) 
+		return (lng-2);
+	else 
+		return 0;
+}
+