diff -Nru linux/arch/mips/sibyte/swarm/dbg_io.c.orig linux/arch/mips/sibyte/swarm/dbg_io.c
--- linux/arch/mips/sibyte/swarm/dbg_io.c.orig	Wed Dec 12 15:21:14 2001
+++ linux/arch/mips/sibyte/swarm/dbg_io.c	Thu Dec 13 14:33:59 2001
@@ -0,0 +1,157 @@
+/*
+ * kgdb debug routines for swarm board.
+ *
+ * Copyright (C) 2001 MontaVista Software Inc.
+ * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
+ *
+ * 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.
+ *
+ */
+
+/* -------------------- BEGINNING OF CONFIG --------------------- */
+#include <linux/config.h>
+#if defined(CONFIG_SMP)
+#warn "kgdb is not quite ready for SMP yet!"
+#endif
+
+/*
+ * We use the second serial port for kgdb traffic.
+ * 	115200, 8, N, 1.
+ */
+
+#define	DUART_BASE		0xb0060200
+#define	BAUD_RATE		115200
+#define	DATA_BITS		8	/* or 7 */
+#define	PARITY			0	/* 1: odd, 2: even */
+#define STOP_BITS		1	/* or 2 */
+
+static int duart_initialized = 0;	/* 0: need to be init'ed by kgdb */
+
+/* -------------------- END OF CONFIG --------------------- */
+
+#include <asm/sibyte/64bit.h>
+
+#define MODE1			0x00
+#define MODE2			0x10
+#define STATUS			0x20
+#define CLK_SEL			0x30
+#define CMD			0x50
+#define RX_HOLD			0x60
+#define TX_HOLD			0x70
+
+#define VAL_STATUS_RX_RDY       (1 << 0)
+#define VAL_STATUS_TX_RDY       (1 << 2)
+
+#define	duart_out(reg, val)	out64(val, DUART_BASE + reg)
+#define duart_in(reg)		in64(DUART_BASE + reg)
+
+void putDebugChar(unsigned char c);
+unsigned char getDebugChar(void);
+static void
+duart_init(int baud, int data, int parity, int stop)
+{
+	unsigned int mode1 = 0;
+	unsigned int mode2 = 0;
+	unsigned int clk_divisor;
+
+	/* data */
+	switch (data) {
+	case 8:
+		break;
+	case 7:
+		mode1 |= 2;
+		break;
+	default:		/* panic */
+		break;
+	}
+
+	/* parity */
+	switch (parity) {
+	case 0:
+		mode1 |= 2 << 3;
+		break;
+	case 1:		/* odd */
+		mode1 |= 1 << 2;
+		break;
+	case 2:		/* even */
+		break;
+	default:		/* panic */
+		break;
+	}
+
+	/* stop */
+	switch (stop) {
+	case 1:
+		break;
+	case 2:
+		mode2 |= 1 << 3;
+	default:		/* panic */
+		break;
+	}
+
+	/* data */
+	switch (baud) {
+	case 200:
+	case 300:
+	case 1200:
+		clk_divisor = 4095;
+		break;
+	case 1800:
+		clk_divisor = 2776;
+		break;
+	case 2400:
+		clk_divisor = 2082;
+		break;
+	case 4800:
+		clk_divisor = 1040;
+		break;
+	case 9600:
+		clk_divisor = 519;
+		break;
+	case 19200:
+		clk_divisor = 259;
+		break;
+	case 38400:
+		clk_divisor = 129;
+		break;
+	case 57600:
+		clk_divisor = 85;
+		break;
+	case 115200:
+		clk_divisor = 42;
+		break;
+	default:		/* panic */
+		break;
+	}
+
+	duart_out(MODE1, mode1);
+	duart_out(MODE2, mode2);
+	duart_out(CLK_SEL, clk_divisor);
+
+	duart_out(CMD, 1 | (1 << 2));	/* enable rx and tx */
+}
+
+void
+putDebugChar(unsigned char c)
+{
+	if (!duart_initialized) {
+		duart_initialized = 1;
+		duart_init(BAUD_RATE, DATA_BITS, PARITY, STOP_BITS);
+	}
+	while ((duart_in(STATUS) & VAL_STATUS_TX_RDY) == 0) ;
+	duart_out(TX_HOLD, c);
+}
+
+unsigned char
+getDebugChar(void)
+{
+	if (!duart_initialized) {
+		duart_initialized = 1;
+		duart_init(BAUD_RATE, DATA_BITS, PARITY, STOP_BITS);
+	}
+	while ((duart_in(STATUS) & VAL_STATUS_RX_RDY) == 0) ;
+	return duart_in(RX_HOLD);
+}