powerpc: Simplify and clean up the xmon terminal I/O

This factors out the common bits of arch/powerpc/xmon/start_*.c into
a new nonstdio.c, and removes some stuff that was supposed to make
xmon's I/O routines somewhat stdio-like but was never used.

It also makes the parsing of the xmon= command line option common,
so that ppc32 can now use xmon={off,on,early} also.

Signed-off-by: Paul Mackerras <paulus@samba.org>

11 files changed, 236 insertions, 728 deletions

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index e22856ecb5a0..26bb1fe6384b 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -51,6 +51,7 @@
 #include <asm/page.h>
 #include <asm/mmu.h>
 #include <asm/lmb.h>
+#include <asm/xmon.h>
 
 #undef DEBUG
 
@@ -559,3 +560,23 @@ void __init smp_setup_cpu_maps(void)
 #endif /* CONFIG_PPC64 */
 }
 #endif /* CONFIG_SMP */
+
+#ifdef CONFIG_XMON
+static int __init early_xmon(char *p)
+{
+	/* ensure xmon is enabled */
+	if (p) {
+		if (strncmp(p, "on", 2) == 0)
+			xmon_init(1);
+		if (strncmp(p, "off", 3) == 0)
+			xmon_init(0);
+		if (strncmp(p, "early", 5) != 0)
+			return 0;
+	}
+	xmon_init(1);
+	debugger(NULL);
+
+	return 0;
+}
+early_param("xmon", early_xmon);
+#endif
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 3af2631e3fab..0fbc73f7f828 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -303,14 +303,9 @@ void __init setup_arch(char **cmdline_p)
 		pmac_feature_init();	/* New cool way */
 #endif
 
-#ifdef CONFIG_XMON
-	xmon_map_scc();
-	if (strstr(cmd_line, "xmon")) {
-		xmon_init(1);
-		debugger(NULL);
-	}
-#endif /* CONFIG_XMON */
-	if ( ppc_md.progress ) ppc_md.progress("setup_arch: enter", 0x3eab);
+#ifdef CONFIG_XMON_DEFAULT
+	xmon_init(1);
+#endif
 
 #if defined(CONFIG_KGDB)
 	if (ppc_md.kgdb_map_scc)
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 0471e843b6c5..54c606f680b3 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -858,26 +858,6 @@ int check_legacy_ioport(unsigned long base_port)
 }
 EXPORT_SYMBOL(check_legacy_ioport);
 
-#ifdef CONFIG_XMON
-static int __init early_xmon(char *p)
-{
-	/* ensure xmon is enabled */
-	if (p) {
-		if (strncmp(p, "on", 2) == 0)
-			xmon_init(1);
-		if (strncmp(p, "off", 3) == 0)
-			xmon_init(0);
-		if (strncmp(p, "early", 5) != 0)
-			return 0;
-	}
-	xmon_init(1);
-	debugger(NULL);
-
-	return 0;
-}
-early_param("xmon", early_xmon);
-#endif
-
 void cpu_die(void)
 {
 	if (ppc_md.cpu_die)
diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile
index 79a784f0e7a9..b20312e5ed27 100644
--- a/arch/powerpc/xmon/Makefile
+++ b/arch/powerpc/xmon/Makefile
@@ -8,4 +8,4 @@ obj-$(CONFIG_8xx)	+= start_8xx.o
 obj-$(CONFIG_6xx)	+= start_32.o
 obj-$(CONFIG_4xx)	+= start_32.o
 obj-$(CONFIG_PPC64)	+= start_64.o
-obj-y			+= xmon.o ppc-dis.o ppc-opc.o subr_prf.o setjmp.o
+obj-y			+= xmon.o ppc-dis.o ppc-opc.o setjmp.o nonstdio.o
diff --git a/arch/powerpc/xmon/nonstdio.c b/arch/powerpc/xmon/nonstdio.c
new file mode 100644
index 000000000000..78765833f4c0
--- /dev/null
+++ b/arch/powerpc/xmon/nonstdio.c
@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 1996-2005 Paul Mackerras.
+ *
+ *      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.
+ */
+#include <linux/string.h>
+#include <asm/time.h>
+#include "nonstdio.h"
+
+int xmon_putchar(int c)
+{
+	char ch = c;
+
+	if (c == '\n')
+		xmon_putchar('\r');
+	return xmon_write(&ch, 1) == 1? c: -1;
+}
+
+static char line[256];
+static char *lineptr;
+static int lineleft;
+
+int xmon_expect(const char *str, unsigned long timeout)
+{
+	int c;
+	unsigned long t0;
+
+	/* assume 25MHz default timebase if tb_ticks_per_sec not set yet */
+	timeout *= tb_ticks_per_sec? tb_ticks_per_sec: 25000000;
+	t0 = get_tbl();
+	do {
+		lineptr = line;
+		for (;;) {
+			c = xmon_read_poll();
+			if (c == -1) {
+				if (get_tbl() - t0 > timeout)
+					return 0;
+				continue;
+			}
+			if (c == '\n')
+				break;
+			if (c != '\r' && lineptr < &line[sizeof(line) - 1])
+				*lineptr++ = c;
+		}
+		*lineptr = 0;
+	} while (strstr(line, str) == NULL);
+	return 1;
+}
+
+int xmon_getchar(void)
+{
+	int c;
+
+	if (lineleft == 0) {
+		lineptr = line;
+		for (;;) {
+			c = xmon_readchar();
+			if (c == -1 || c == 4)
+				break;
+			if (c == '\r' || c == '\n') {
+				*lineptr++ = '\n';
+				xmon_putchar('\n');
+				break;
+			}
+			switch (c) {
+			case 0177:
+			case '\b':
+				if (lineptr > line) {
+					xmon_putchar('\b');
+					xmon_putchar(' ');
+					xmon_putchar('\b');
+					--lineptr;
+				}
+				break;
+			case 'U' & 0x1F:
+				while (lineptr > line) {
+					xmon_putchar('\b');
+					xmon_putchar(' ');
+					xmon_putchar('\b');
+					--lineptr;
+				}
+				break;
+			default:
+				if (lineptr >= &line[sizeof(line) - 1])
+					xmon_putchar('\a');
+				else {
+					xmon_putchar(c);
+					*lineptr++ = c;
+				}
+			}
+		}
+		lineleft = lineptr - line;
+		lineptr = line;
+	}
+	if (lineleft == 0)
+		return -1;
+	--lineleft;
+	return *lineptr++;
+}
+
+char *xmon_gets(char *str, int nb)
+{
+	char *p;
+	int c;
+
+	for (p = str; p < str + nb - 1; ) {
+		c = xmon_getchar();
+		if (c == -1) {
+			if (p == str)
+				return NULL;
+			break;
+		}
+		*p++ = c;
+		if (c == '\n')
+			break;
+	}
+	*p = 0;
+	return str;
+}
+
+void xmon_printf(const char *format, ...)
+{
+	va_list args;
+	int n;
+	static char xmon_outbuf[1024];
+
+	va_start(args, format);
+	n = vsnprintf(xmon_outbuf, sizeof(xmon_outbuf), format, args);
+	va_end(args);
+	xmon_write(xmon_outbuf, n);
+}
diff --git a/arch/powerpc/xmon/nonstdio.h b/arch/powerpc/xmon/nonstdio.h
index 84211a21c6f4..47cebbd2b1b1 100644
--- a/arch/powerpc/xmon/nonstdio.h
+++ b/arch/powerpc/xmon/nonstdio.h
@@ -1,22 +1,14 @@
-typedef int	FILE;
-extern FILE *xmon_stdin, *xmon_stdout;
 #define EOF	(-1)
-#define stdin	xmon_stdin
-#define stdout	xmon_stdout
+
 #define printf	xmon_printf
-#define fprintf	xmon_fprintf
-#define fputs	xmon_fputs
-#define fgets	xmon_fgets
 #define putchar	xmon_putchar
-#define getchar	xmon_getchar
-#define putc	xmon_putc
-#define getc	xmon_getc
-#define fopen(n, m)	NULL
-#define fflush(f)	do {} while (0)
-#define fclose(f)	do {} while (0)
-extern char *fgets(char *, int, void *);
-extern void xmon_printf(const char *, ...);
-extern void xmon_fprintf(void *, const char *, ...);
-extern void xmon_sprintf(char *, const char *, ...);
 
-#define perror(s)	printf("%s: no files!\n", (s))
+extern int xmon_putchar(int c);
+extern int xmon_getchar(void);
+extern char *xmon_gets(char *, int);
+extern void xmon_printf(const char *, ...);
+extern void xmon_map_scc(void);
+extern int xmon_expect(const char *str, unsigned long timeout);
+extern int xmon_write(void *ptr, int nb);
+extern int xmon_readchar(void);
+extern int xmon_read_poll(void);
diff --git a/arch/powerpc/xmon/start_32.c b/arch/powerpc/xmon/start_32.c
index 69b658c0f760..c2464df4217e 100644
--- a/arch/powerpc/xmon/start_32.c
+++ b/arch/powerpc/xmon/start_32.c
@@ -11,7 +11,6 @@
 #include <linux/cuda.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
-#include <linux/sysrq.h>
 #include <linux/bitops.h>
 #include <asm/xmon.h>
 #include <asm/prom.h>
@@ -22,10 +21,11 @@
 #include <asm/processor.h>
 #include <asm/delay.h>
 #include <asm/btext.h>
+#include <asm/time.h>
+#include "nonstdio.h"
 
 static volatile unsigned char __iomem *sccc, *sccd;
 unsigned int TXRDY, RXRDY, DLAB;
-static int xmon_expect(const char *str, unsigned int timeout);
 
 static int use_serial;
 static int use_screen;
@@ -33,16 +33,6 @@ static int via_modem;
 static int xmon_use_sccb;
 static struct device_node *channel_node;
 
-#define TB_SPEED	25000000
-
-static inline unsigned int readtb(void)
-{
-	unsigned int ret;
-
-	asm volatile("mftb %0" : "=r" (ret) :);
-	return ret;
-}
-
 void buf_access(void)
 {
 	if (DLAB)
@@ -91,23 +81,7 @@ static unsigned long chrp_find_phys_io_base(void)
 }
 #endif /* CONFIG_PPC_CHRP */
 
-#ifdef CONFIG_MAGIC_SYSRQ
-static void sysrq_handle_xmon(int key, struct pt_regs *regs,
-			      struct tty_struct *tty)
-{
-	xmon(regs);
-}
-
-static struct sysrq_key_op sysrq_xmon_op =
-{
-	.handler =	sysrq_handle_xmon,
-	.help_msg =	"Xmon",
-	.action_msg =	"Entering xmon",
-};
-#endif
-
-void
-xmon_map_scc(void)
+void xmon_map_scc(void)
 {
 #ifdef CONFIG_PPC_MULTIPLATFORM
 	volatile unsigned char __iomem *base;
@@ -217,8 +191,6 @@ xmon_map_scc(void)
 	RXRDY = 1;
 	DLAB = 0x80;
 #endif /* platform */
-
-	register_sysrq_key('x', &sysrq_xmon_op);
 }
 
 static int scc_initialized = 0;
@@ -238,8 +210,7 @@ static inline void do_poll_adb(void)
 #endif /* CONFIG_ADB_CUDA */
 }
 
-int
-xmon_write(void *handle, void *ptr, int nb)
+int xmon_write(void *ptr, int nb)
 {
 	char *p = ptr;
 	int i, c, ct;
@@ -311,8 +282,7 @@ static unsigned char xmon_shift_keytab[128] =
 	"\0.\0*\0+\0\0\0\0\0/\r\0-\0"			/* 0x40 - 0x4f */
 	"\0\0000123456789\0\0\0";			/* 0x50 - 0x5f */
 
-static int
-xmon_get_adb_key(void)
+static int xmon_get_adb_key(void)
 {
 	int k, t, on;
 
@@ -350,32 +320,21 @@ xmon_get_adb_key(void)
 }
 #endif /* CONFIG_BOOTX_TEXT */
 
-int
-xmon_read(void *handle, void *ptr, int nb)
+int xmon_readchar(void)
 {
-    char *p = ptr;
-    int i;
-
 #ifdef CONFIG_BOOTX_TEXT
-    if (use_screen) {
-	for (i = 0; i < nb; ++i)
-	    *p++ = xmon_get_adb_key();
-	return i;
-    }
+	if (use_screen)
+		return xmon_get_adb_key();
 #endif
-    if (!scc_initialized)
-	xmon_init_scc();
-    for (i = 0; i < nb; ++i) {
+	if (!scc_initialized)
+		xmon_init_scc();
 	while ((*sccc & RXRDY) == 0)
-	    do_poll_adb();
+		do_poll_adb();
 	buf_access();
-	*p++ = *sccd;
-    }
-    return i;
+	return *sccd;
 }
 
-int
-xmon_read_poll(void)
+int xmon_read_poll(void)
 {
 	if ((*sccc & RXRDY) == 0) {
 		do_poll_adb();
@@ -395,8 +354,7 @@ static unsigned char scc_inittab[] = {
     3,  0xc1,		/* rx enable, 8 bits */
 };
 
-void
-xmon_init_scc(void)
+void xmon_init_scc(void)
 {
 	if ( _machine == _MACH_chrp )
 	{
@@ -410,6 +368,7 @@ xmon_init_scc(void)
 	else if ( _machine == _MACH_Pmac )
 	{
 		int i, x;
+		unsigned long timeout;
 
 		if (channel_node != 0)
 			pmac_call_feature(
@@ -424,8 +383,12 @@ xmon_init_scc(void)
 				PMAC_FTR_MODEM_ENABLE,
 				channel_node, 0, 1);
 			printk(KERN_INFO "Modem powered up by debugger !\n");
-			t0 = readtb();
-			while (readtb() - t0 < 3*TB_SPEED)
+			t0 = get_tbl();
+			timeout = 3 * tb_ticks_per_sec;
+			if (timeout == 0)
+				/* assume 25MHz if tb_ticks_per_sec not set */
+				timeout = 75000000;
+			while (get_tbl() - t0 < timeout)
 				eieio();
 		}
 		/* use the B channel if requested */
@@ -447,164 +410,19 @@ xmon_init_scc(void)
 	scc_initialized = 1;
 	if (via_modem) {
 		for (;;) {
-			xmon_write(NULL, "ATE1V1\r", 7);
+			xmon_write("ATE1V1\r", 7);
 			if (xmon_expect("OK", 5)) {
-				xmon_write(NULL, "ATA\r", 4);
+				xmon_write("ATA\r", 4);
 				if (xmon_expect("CONNECT", 40))
 					break;
 			}
-			xmon_write(NULL, "+++", 3);
+			xmon_write("+++", 3);
 			xmon_expect("OK", 3);
 		}
 	}
 }
 
-void *xmon_stdin;
-void *xmon_stdout;
-void *xmon_stderr;
-
-int xmon_putc(int c, void *f)
-{
-    char ch = c;
-
-    if (c == '\n')
-	xmon_putc('\r', f);
-    return xmon_write(f, &ch, 1) == 1? c: -1;
-}
-
-int xmon_putchar(int c)
-{
-	return xmon_putc(c, xmon_stdout);
-}
-
-int xmon_fputs(char *str, void *f)
-{
-	int n = strlen(str);
-
-	return xmon_write(f, str, n) == n? 0: -1;
-}
-
-int
-xmon_readchar(void)
-{
-	char ch;
-
-	for (;;) {
-		switch (xmon_read(xmon_stdin, &ch, 1)) {
-		case 1:
-			return ch;
-		case -1:
-			xmon_printf("read(stdin) returned -1\r\n", 0, 0);
-			return -1;
-		}
-	}
-}
-
-static char line[256];
-static char *lineptr;
-static int lineleft;
-
-int xmon_expect(const char *str, unsigned int timeout)
-{
-	int c;
-	unsigned int t0;
-
-	timeout *= TB_SPEED;
-	t0 = readtb();
-	do {
-		lineptr = line;
-		for (;;) {
-			c = xmon_read_poll();
-			if (c == -1) {
-				if (readtb() - t0 > timeout)
-					return 0;
-				continue;
-			}
-			if (c == '\n')
-				break;
-			if (c != '\r' && lineptr < &line[sizeof(line) - 1])
-				*lineptr++ = c;
-		}
-		*lineptr = 0;
-	} while (strstr(line, str) == NULL);
-	return 1;
-}
-
-int
-xmon_getchar(void)
-{
-    int c;
-
-    if (lineleft == 0) {
-	lineptr = line;
-	for (;;) {
-	    c = xmon_readchar();
-	    if (c == -1 || c == 4)
-		break;
-	    if (c == '\r' || c == '\n') {
-		*lineptr++ = '\n';
-		xmon_putchar('\n');
-		break;
-	    }
-	    switch (c) {
-	    case 0177:
-	    case '\b':
-		if (lineptr > line) {
-		    xmon_putchar('\b');
-		    xmon_putchar(' ');
-		    xmon_putchar('\b');
-		    --lineptr;
-		}
-		break;
-	    case 'U' & 0x1F:
-		while (lineptr > line) {
-		    xmon_putchar('\b');
-		    xmon_putchar(' ');
-		    xmon_putchar('\b');
-		    --lineptr;
-		}
-		break;
-	    default:
-		if (lineptr >= &line[sizeof(line) - 1])
-		    xmon_putchar('\a');
-		else {
-		    xmon_putchar(c);
-		    *lineptr++ = c;
-		}
-	    }
-	}
-	lineleft = lineptr - line;
-	lineptr = line;
-    }
-    if (lineleft == 0)
-	return -1;
-    --lineleft;
-    return *lineptr++;
-}
-
-char *
-xmon_fgets(char *str, int nb, void *f)
-{
-    char *p;
-    int c;
-
-    for (p = str; p < str + nb - 1; ) {
-	c = xmon_getchar();
-	if (c == -1) {
-	    if (p == str)
-		return NULL;
-	    break;
-	}
-	*p++ = c;
-	if (c == '\n')
-	    break;
-    }
-    *p = 0;
-    return str;
-}
-
-void
-xmon_enter(void)
+void xmon_enter(void)
 {
 #ifdef CONFIG_ADB_PMU
 	if (_machine == _MACH_Pmac) {
@@ -613,8 +431,7 @@ xmon_enter(void)
 #endif
 }
 
-void
-xmon_leave(void)
+void xmon_leave(void)
 {
 #ifdef CONFIG_ADB_PMU
 	if (_machine == _MACH_Pmac) {
diff --git a/arch/powerpc/xmon/start_64.c b/arch/powerpc/xmon/start_64.c
index e50c158191e1..712552c4f242 100644
--- a/arch/powerpc/xmon/start_64.c
+++ b/arch/powerpc/xmon/start_64.c
@@ -6,182 +6,29 @@
  *      as published by the Free Software Foundation; either version
  *      2 of the License, or (at your option) any later version.
  */
-#include <linux/config.h>
-#include <linux/string.h>
-#include <linux/kernel.h>
-#include <linux/errno.h>
-#include <linux/sysrq.h>
-#include <linux/init.h>
 #include <asm/machdep.h>
-#include <asm/io.h>
-#include <asm/page.h>
-#include <asm/prom.h>
-#include <asm/processor.h>
 #include <asm/udbg.h>
-#include <asm/system.h>
 #include "nonstdio.h"
 
-#ifdef CONFIG_MAGIC_SYSRQ
-
-static void sysrq_handle_xmon(int key, struct pt_regs *pt_regs,
-			      struct tty_struct *tty) 
-{
-	/* ensure xmon is enabled */
-	xmon_init(1);
-	debugger(pt_regs);
-}
-
-static struct sysrq_key_op sysrq_xmon_op = 
+void xmon_map_scc(void)
 {
-	.handler =	sysrq_handle_xmon,
-	.help_msg =	"Xmon",
-	.action_msg =	"Entering xmon",
-};
-
-static int __init setup_xmon_sysrq(void)
-{
-	register_sysrq_key('x', &sysrq_xmon_op);
-	return 0;
 }
-__initcall(setup_xmon_sysrq);
-#endif /* CONFIG_MAGIC_SYSRQ */
 
-int
-xmon_write(void *handle, void *ptr, int nb)
+int xmon_write(void *ptr, int nb)
 {
 	return udbg_write(ptr, nb);
 }
 
-int
-xmon_read(void *handle, void *ptr, int nb)
+int xmon_readchar(void)
 {
-	return udbg_read(ptr, nb);
+	if (udbg_getc)
+		return udbg_getc();
+	return -1;
 }
 
-int
-xmon_read_poll(void)
+int xmon_read_poll(void)
 {
 	if (udbg_getc_poll)
 		return udbg_getc_poll();
 	return -1;
 }
- 
-FILE *xmon_stdin;
-FILE *xmon_stdout;
-
-int
-xmon_putc(int c, void *f)
-{
-	char ch = c;
-
-	if (c == '\n')
-		xmon_putc('\r', f);
-	return xmon_write(f, &ch, 1) == 1? c: -1;
-}
-
-int
-xmon_putchar(int c)
-{
-	return xmon_putc(c, xmon_stdout);
-}
-
-int
-xmon_fputs(char *str, void *f)
-{
-	int n = strlen(str);
-
-	return xmon_write(f, str, n) == n? 0: -1;
-}
-
-int
-xmon_readchar(void)
-{
-	char ch;
-
-	for (;;) {
-		switch (xmon_read(xmon_stdin, &ch, 1)) {
-		case 1:
-			return ch;
-		case -1:
-			xmon_printf("read(stdin) returned -1\r\n", 0, 0);
-			return -1;
-		}
-	}
-}
-
-static char line[256];
-static char *lineptr;
-static int lineleft;
-
-int
-xmon_getchar(void)
-{
-	int c;
-
-	if (lineleft == 0) {
-		lineptr = line;
-		for (;;) {
-			c = xmon_readchar();
-			if (c == -1 || c == 4)
-				break;
-			if (c == '\r' || c == '\n') {
-				*lineptr++ = '\n';
-				xmon_putchar('\n');
-				break;
-			}
-			switch (c) {
-			case 0177:
-			case '\b':
-				if (lineptr > line) {
-					xmon_putchar('\b');
-					xmon_putchar(' ');
-					xmon_putchar('\b');
-					--lineptr;
-				}
-				break;
-			case 'U' & 0x1F:
-				while (lineptr > line) {
-					xmon_putchar('\b');
-					xmon_putchar(' ');
-					xmon_putchar('\b');
-					--lineptr;
-				}
-				break;
-			default:
-				if (lineptr >= &line[sizeof(line) - 1])
-					xmon_putchar('\a');
-				else {
-					xmon_putchar(c);
-					*lineptr++ = c;
-				}
-			}
-		}
-		lineleft = lineptr - line;
-		lineptr = line;
-	}
-	if (lineleft == 0)
-		return -1;
-	--lineleft;
-	return *lineptr++;
-}
-
-char *
-xmon_fgets(char *str, int nb, void *f)
-{
-	char *p;
-	int c;
-
-	for (p = str; p < str + nb - 1; ) {
-		c = xmon_getchar();
-		if (c == -1) {
-			if (p == str)
-				return NULL;
-			break;
-		}
-		*p++ = c;
-		if (c == '\n')
-			break;
-	}
-	*p = 0;
-	return str;
-}
diff --git a/arch/powerpc/xmon/start_8xx.c b/arch/powerpc/xmon/start_8xx.c
index a48bd594cf61..4c17b0486ad5 100644
--- a/arch/powerpc/xmon/start_8xx.c
+++ b/arch/powerpc/xmon/start_8xx.c
@@ -15,273 +15,30 @@
 #include <asm/8xx_immap.h>
 #include <asm/mpc8xx.h>
 #include <asm/commproc.h>
+#include "nonstdio.h"
 
-extern void xmon_printf(const char *fmt, ...);
 extern int xmon_8xx_write(char *str, int nb);
 extern int xmon_8xx_read_poll(void);
 extern int xmon_8xx_read_char(void);
-void prom_drawhex(uint);
-void prom_drawstring(const char *str);
 
-static int use_screen = 1; /* default */
-
-#define TB_SPEED	25000000
-
-static inline unsigned int readtb(void)
-{
-	unsigned int ret;
-
-	asm volatile("mftb %0" : "=r" (ret) :);
-	return ret;
-}
-
-void buf_access(void)
-{
-}
-
-void
-xmon_map_scc(void)
+void xmon_map_scc(void)
 {
-
 	cpmp = (cpm8xx_t *)&(((immap_t *)IMAP_ADDR)->im_cpm);
-	use_screen = 0;
-	
-	prom_drawstring("xmon uses serial port\n");
 }
 
-static int scc_initialized = 0;
-
 void xmon_init_scc(void);
 
-int
-xmon_write(void *handle, void *ptr, int nb)
+int xmon_write(void *ptr, int nb)
 {
-	char *p = ptr;
-	int i, c, ct;
-
-	if (!scc_initialized)
-		xmon_init_scc();
-
 	return(xmon_8xx_write(ptr, nb));
 }
 
-int xmon_wants_key;
-
-int
-xmon_read(void *handle, void *ptr, int nb)
+int xmon_readchar(void)
 {
-	char *p = ptr;
-	int i;
-
-	if (!scc_initialized)
-		xmon_init_scc();
-
-	for (i = 0; i < nb; ++i) {
-		*p++ = xmon_8xx_read_char();
-	}
-	return i;
+	return xmon_8xx_read_char();
 }
 
-int
-xmon_read_poll(void)
+int xmon_read_poll(void)
 {
 	return(xmon_8xx_read_poll());
 }
-
-void
-xmon_init_scc()
-{
-	scc_initialized = 1;
-}
-
-#if 0
-extern int (*prom_entry)(void *);
-
-int
-xmon_exit(void)
-{
-    struct prom_args {
-	char *service;
-    } args;
-
-    for (;;) {
-	args.service = "exit";
-	(*prom_entry)(&args);
-    }
-}
-#endif
-
-void *xmon_stdin;
-void *xmon_stdout;
-void *xmon_stderr;
-
-void
-xmon_init(void)
-{
-}
-
-int
-xmon_putc(int c, void *f)
-{
-    char ch = c;
-
-    if (c == '\n')
-	xmon_putc('\r', f);
-    return xmon_write(f, &ch, 1) == 1? c: -1;
-}
-
-int
-xmon_putchar(int c)
-{
-    return xmon_putc(c, xmon_stdout);
-}
-
-int
-xmon_fputs(char *str, void *f)
-{
-    int n = strlen(str);
-
-    return xmon_write(f, str, n) == n? 0: -1;
-}
-
-int
-xmon_readchar(void)
-{
-    char ch;
-
-    for (;;) {
-	switch (xmon_read(xmon_stdin, &ch, 1)) {
-	case 1:
-	    return ch;
-	case -1:
-	    xmon_printf("read(stdin) returned -1\r\n", 0, 0);
-	    return -1;
-	}
-    }
-}
-
-static char line[256];
-static char *lineptr;
-static int lineleft;
-
-#if 0
-int xmon_expect(const char *str, unsigned int timeout)
-{
-	int c;
-	unsigned int t0;
-
-	timeout *= TB_SPEED;
-	t0 = readtb();
-	do {
-		lineptr = line;
-		for (;;) {
-			c = xmon_read_poll();
-			if (c == -1) {
-				if (readtb() - t0 > timeout)
-					return 0;
-				continue;
-			}
-			if (c == '\n')
-				break;
-			if (c != '\r' && lineptr < &line[sizeof(line) - 1])
-				*lineptr++ = c;
-		}
-		*lineptr = 0;
-	} while (strstr(line, str) == NULL);
-	return 1;
-}
-#endif
-
-int
-xmon_getchar(void)
-{
-    int c;
-
-    if (lineleft == 0) {
-	lineptr = line;
-	for (;;) {
-	    c = xmon_readchar();
-	    if (c == -1 || c == 4)
-		break;
-	    if (c == '\r' || c == '\n') {
-		*lineptr++ = '\n';
-		xmon_putchar('\n');
-		break;
-	    }
-	    switch (c) {
-	    case 0177:
-	    case '\b':
-		if (lineptr > line) {
-		    xmon_putchar('\b');
-		    xmon_putchar(' ');
-		    xmon_putchar('\b');
-		    --lineptr;
-		}
-		break;
-	    case 'U' & 0x1F:
-		while (lineptr > line) {
-		    xmon_putchar('\b');
-		    xmon_putchar(' ');
-		    xmon_putchar('\b');
-		    --lineptr;
-		}
-		break;
-	    default:
-		if (lineptr >= &line[sizeof(line) - 1])
-		    xmon_putchar('\a');
-		else {
-		    xmon_putchar(c);
-		    *lineptr++ = c;
-		}
-	    }
-	}
-	lineleft = lineptr - line;
-	lineptr = line;
-    }
-    if (lineleft == 0)
-	return -1;
-    --lineleft;
-    return *lineptr++;
-}
-
-char *
-xmon_fgets(char *str, int nb, void *f)
-{
-    char *p;
-    int c;
-
-    for (p = str; p < str + nb - 1; ) {
-	c = xmon_getchar();
-	if (c == -1) {
-	    if (p == str)
-		return 0;
-	    break;
-	}
-	*p++ = c;
-	if (c == '\n')
-	    break;
-    }
-    *p = 0;
-    return str;
-}
-
-void
-prom_drawhex(uint val)
-{
-	unsigned char buf[10];
-
-	int i;
-	for (i = 7;  i >= 0;  i--)
-	{
-		buf[i] = "0123456789abcdef"[val & 0x0f];
-		val >>= 4;
-	}
-	buf[8] = '\0';
-	xmon_fputs(buf, xmon_stdout);
-}
-
-void
-prom_drawstring(const char *str)
-{
-	xmon_fputs(str, xmon_stdout);
-}
diff --git a/arch/powerpc/xmon/subr_prf.c b/arch/powerpc/xmon/subr_prf.c
deleted file mode 100644
index b48738c6dd33..000000000000
--- a/arch/powerpc/xmon/subr_prf.c
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * Written by Cort Dougan to replace the version originally used
- * by Paul Mackerras, which came from NetBSD and thus had copyright
- * conflicts with Linux.
- *
- * This file makes liberal use of the standard linux utility
- * routines to reduce the size of the binary.  We assume we can
- * trust some parts of Linux inside the debugger.
- *   -- Cort (cort@cs.nmt.edu)
- *
- * Copyright (C) 1999 Cort Dougan.
- *
- *      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.
- */
-
-#include <linux/kernel.h>
-#include <linux/string.h>
-#include <linux/module.h>
-#include <stdarg.h>
-#include "nonstdio.h"
-
-extern int xmon_write(void *, void *, int);
-
-void xmon_vfprintf(void *f, const char *fmt, va_list ap)
-{
-	static char xmon_buf[2048];
-	int n;
-
-	n = vsprintf(xmon_buf, fmt, ap);
-	xmon_write(f, xmon_buf, n);
-}
-
-void xmon_printf(const char *fmt, ...)
-{
-	va_list ap;
-
-	va_start(ap, fmt);
-	xmon_vfprintf(stdout, fmt, ap);
-	va_end(ap);
-}
-EXPORT_SYMBOL(xmon_printf);
-
-void xmon_fprintf(void *f, const char *fmt, ...)
-{
-	va_list ap;
-
-	va_start(ap, fmt);
-	xmon_vfprintf(f, fmt, ap);
-	va_end(ap);
-}
-
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 1124f1146202..b43a57425ea9 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1,7 +1,7 @@
 /*
  * Routines providing a simple monitor for use on the PowerMac.
  *
- * Copyright (C) 1996 Paul Mackerras.
+ * Copyright (C) 1996-2005 Paul Mackerras.
  *
  *      This program is free software; you can redistribute it and/or
  *      modify it under the terms of the GNU General Public License
@@ -18,6 +18,7 @@
 #include <linux/kallsyms.h>
 #include <linux/cpumask.h>
 #include <linux/module.h>
+#include <linux/sysrq.h>
 
 #include <asm/ptrace.h>
 #include <asm/string.h>
@@ -144,15 +145,10 @@ static void xmon_print_symbol(unsigned long address, const char *mid,
 static const char *getvecname(unsigned long vec);
 
 extern int print_insn_powerpc(unsigned long, unsigned long, int);
-extern void printf(const char *fmt, ...);
-extern void xmon_vfprintf(void *f, const char *fmt, va_list ap);
-extern int xmon_putc(int c, void *f);
-extern int putchar(int ch);
 
 extern void xmon_enter(void);
 extern void xmon_leave(void);
 
-extern int xmon_read_poll(void);
 extern long setjmp(long *);
 extern void longjmp(long *, long);
 extern void xmon_save_regs(struct pt_regs *);
@@ -748,7 +744,6 @@ cmds(struct pt_regs *excp)
 		printf("%x:", smp_processor_id());
 #endif /* CONFIG_SMP */
 		printf("mon> ");
-		fflush(stdout);
 		flush_input();
 		termch = 0;
 		cmd = skipbl();
@@ -2151,7 +2146,6 @@ memzcan(void)
 		ok = mread(a, &v, 1);
 		if (ok && !ook) {
 			printf("%.8x .. ", a);
-			fflush(stdout);
 		} else if (!ok && ook)
 			printf("%.8x\n", a - mskip);
 		ook = ok;
@@ -2372,7 +2366,7 @@ int
 inchar(void)
 {
 	if (lineptr == NULL || *lineptr == 0) {
-		if (fgets(line, sizeof(line), stdin) == NULL) {
+		if (xmon_gets(line, sizeof(line)) == NULL) {
 			lineptr = NULL;
 			return EOF;
 		}
@@ -2526,4 +2520,29 @@ void xmon_init(int enable)
 		__debugger_dabr_match = NULL;
 		__debugger_fault_handler = NULL;
 	}
+	xmon_map_scc();
 }
+
+#ifdef CONFIG_MAGIC_SYSRQ
+static void sysrq_handle_xmon(int key, struct pt_regs *pt_regs,
+			      struct tty_struct *tty) 
+{
+	/* ensure xmon is enabled */
+	xmon_init(1);
+	debugger(pt_regs);
+}
+
+static struct sysrq_key_op sysrq_xmon_op = 
+{
+	.handler =	sysrq_handle_xmon,
+	.help_msg =	"Xmon",
+	.action_msg =	"Entering xmon",
+};
+
+static int __init setup_xmon_sysrq(void)
+{
+	register_sysrq_key('x', &sysrq_xmon_op);
+	return 0;
+}
+__initcall(setup_xmon_sysrq);
+#endif /* CONFIG_MAGIC_SYSRQ */