[PATCH] powerpc: Unify udbg (#2)

This patch unifies udbg for both ppc32 and ppc64 when building the
merged achitecture. xmon now has a single "back end". The powermac udbg
stuff gets enriched with some ADB capabilities and btext output. In
addition, the early_init callback is now called on ppc32 as well,
approx. in the same order as ppc64 regarding device-tree manipulations.
The init sequences of ppc32 and ppc64 are getting closer, I'll unify
them in a later patch.

For now, you can force udbg to the scc using "sccdbg" or to btext using
"btextdbg" on powermacs. I'll implement a cleaner way of forcing udbg
output to something else than the autodetected OF output device in a
later patch.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

7 files changed, 470 insertions, 63 deletions

diff --git a/arch/powerpc/platforms/powermac/Makefile b/arch/powerpc/platforms/powermac/Makefile
index c9df44fcf57..3e5370eeb1b 100644
--- a/arch/powerpc/platforms/powermac/Makefile
+++ b/arch/powerpc/platforms/powermac/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_NVRAM)		+= nvram.o
 # ppc64 pmac doesn't define CONFIG_NVRAM but needs nvram stuff
 obj-$(CONFIG_PPC64)		+= nvram.o
 obj-$(CONFIG_SMP)		+= smp.o
+obj-$(CONFIG_PPC_MERGE)		+= udbg_scc.o udbg_adb.o
diff --git a/arch/powerpc/platforms/powermac/feature.c b/arch/powerpc/platforms/powermac/feature.c
index f6e22da2a5d..52a9d0c1b8b 100644
--- a/arch/powerpc/platforms/powermac/feature.c
+++ b/arch/powerpc/platforms/powermac/feature.c
@@ -2607,6 +2607,8 @@ found:
  */
 static void __init probe_uninorth(void)
 {
+	u32 *addrp;
+	phys_addr_t address;
 	unsigned long actrl;
 
 	/* Locate core99 Uni-N */
@@ -2616,20 +2618,23 @@ static void __init probe_uninorth(void)
 		uninorth_node = of_find_node_by_name(NULL, "u3");
 		uninorth_u3 = 1;
 	}
-	if (uninorth_node && uninorth_node->n_addrs > 0) {
-		unsigned long address = uninorth_node->addrs[0].address;
-		uninorth_base = ioremap(address, 0x40000);
-		uninorth_rev = in_be32(UN_REG(UNI_N_VERSION));
-		if (uninorth_u3)
-			u3_ht = ioremap(address + U3_HT_CONFIG_BASE, 0x1000);
-	} else
-		uninorth_node = NULL;
-
-	if (!uninorth_node)
+	if (uninorth_node == NULL)
 		return;
 
-	printk(KERN_INFO "Found %s memory controller & host bridge, revision: %d\n",
-	       uninorth_u3 ? "U3" : "UniNorth", uninorth_rev);
+	addrp = (u32 *)get_property(uninorth_node, "reg", NULL);
+	if (addrp == NULL)
+		return;
+	address = of_translate_address(uninorth_node, addrp);
+	if (address == 0)
+		return;
+	uninorth_base = ioremap(address, 0x40000);
+	uninorth_rev = in_be32(UN_REG(UNI_N_VERSION));
+	if (uninorth_u3)
+		u3_ht = ioremap(address + U3_HT_CONFIG_BASE, 0x1000);
+
+	printk(KERN_INFO "Found %s memory controller & host bridge,"
+	       " revision: %d\n", uninorth_u3 ? "U3" : "UniNorth",
+	       uninorth_rev);
 	printk(KERN_INFO "Mapped at 0x%08lx\n", (unsigned long)uninorth_base);
 
 	/* Set the arbitrer QAck delay according to what Apple does
@@ -2653,18 +2658,17 @@ static void __init probe_one_macio(const char *name, const char *compat, int typ
 {
 	struct device_node*	node;
 	int			i;
-	volatile u32 __iomem *	base;
-	u32*			revp;
+	volatile u32 __iomem	*base;
+	u32			*addrp, *revp;
+	phys_addr_t		addr;
+	u64			size;
 
-	node = find_devices(name);
-	if (!node || !node->n_addrs)
-		return;
-	if (compat)
-		do {
-			if (device_is_compatible(node, compat))
-				break;
-			node = node->next;
-		} while (node);
+	for (node = NULL; (node = of_find_node_by_name(node, name)) != NULL;) {
+		if (!compat)
+			break;
+		if (device_is_compatible(node, compat))
+			break;
+	}
 	if (!node)
 		return;
 	for(i=0; i<MAX_MACIO_CHIPS; i++) {
@@ -2673,14 +2677,28 @@ static void __init probe_one_macio(const char *name, const char *compat, int typ
 		if (macio_chips[i].of_node == node)
 			return;
 	}
+
 	if (i >= MAX_MACIO_CHIPS) {
 		printk(KERN_ERR "pmac_feature: Please increase MAX_MACIO_CHIPS !\n");
 		printk(KERN_ERR "pmac_feature: %s skipped\n", node->full_name);
 		return;
 	}
-	base = ioremap(node->addrs[0].address, node->addrs[0].size);
+	addrp = of_get_pci_address(node, 0, &size);
+	if (addrp == NULL) {
+		printk(KERN_ERR "pmac_feature: %s: can't find base !\n",
+		       node->full_name);
+		return;
+	}
+	addr = of_translate_address(node, addrp);
+	if (addr == 0) {
+		printk(KERN_ERR "pmac_feature: %s, can't translate base !\n",
+		       node->full_name);
+		return;
+	}
+	base = ioremap(addr, (unsigned long)size);
 	if (!base) {
-		printk(KERN_ERR "pmac_feature: Can't map mac-io chip !\n");
+		printk(KERN_ERR "pmac_feature: %s, can't map mac-io chip !\n",
+		       node->full_name);
 		return;
 	}
 	if (type == macio_keylargo) {
diff --git a/arch/powerpc/platforms/powermac/low_i2c.c b/arch/powerpc/platforms/powermac/low_i2c.c
index f3f39e8e337..606e0ed1373 100644
--- a/arch/powerpc/platforms/powermac/low_i2c.c
+++ b/arch/powerpc/platforms/powermac/low_i2c.c
@@ -36,7 +36,7 @@
 
 #ifdef DEBUG
 #define DBG(x...) do {\
-		printk(KERN_DEBUG "KW:" x);	\
+		printk(KERN_DEBUG "low_i2c:" x);	\
 	} while(0)
 #else
 #define DBG(x...)
@@ -342,7 +342,7 @@ static int keywest_low_i2c_func(struct low_i2c_host *host, u8 addr, u8 subaddr,
 static void keywest_low_i2c_add(struct device_node *np)
 {
 	struct low_i2c_host	*host = find_low_i2c_host(NULL);
-	u32			*psteps, *prate, steps, aoffset = 0;
+	u32			*psteps, *prate, *addrp, steps;
 	struct device_node	*parent;
 
 	if (host == NULL) {
@@ -352,6 +352,16 @@ static void keywest_low_i2c_add(struct device_node *np)
 	}
 	memset(host, 0, sizeof(*host));
 
+	/* Apple is kind enough to provide a valid AAPL,address property
+	 * on all i2c keywest nodes so far ... we would have to fallback
+	 * to macio parsing if that wasn't the case
+	 */
+	addrp = (u32 *)get_property(np, "AAPL,address", NULL);
+	if (addrp == NULL) {
+		printk(KERN_ERR "low_i2c: Can't find address for %s\n",
+		       np->full_name);
+		return;
+	}
 	init_MUTEX(&host->mutex);
 	host->np = of_node_get(np);	
 	psteps = (u32 *)get_property(np, "AAPL,address-step", NULL);
@@ -360,12 +370,10 @@ static void keywest_low_i2c_add(struct device_node *np)
 		steps >>= 1;
 	parent = of_get_parent(np);
 	host->num_channels = 1;
-	if (parent && parent->name[0] == 'u') {
+	if (parent && parent->name[0] == 'u')
 		host->num_channels = 2;
-		aoffset = 3;
-	}
 	/* Select interface rate */
-	host->speed = KW_I2C_MODE_100KHZ;
+	host->speed = KW_I2C_MODE_25KHZ;
 	prate = (u32 *)get_property(np, "AAPL,i2c-rate", NULL);
 	if (prate) switch(*prate) {
 	case 100:
@@ -379,9 +387,12 @@ static void keywest_low_i2c_add(struct device_node *np)
 		break;
 	}	
 
+	printk(KERN_INFO "low_i2c: Bus %s found at 0x%08x, %d channels,"
+	       " speed = %d KHz\n",
+	       np->full_name, *addrp, host->num_channels, prate ? *prate : 25);
+
 	host->mode = pmac_low_i2c_mode_std;
-	host->base = ioremap(np->addrs[0].address + aoffset,
-						np->addrs[0].size);
+	host->base = ioremap((*addrp), 0x1000);
 	host->func = keywest_low_i2c_func;
 }
 
diff --git a/arch/powerpc/platforms/powermac/pic.c b/arch/powerpc/platforms/powermac/pic.c
index 90040c49494..ff78eeac10f 100644
--- a/arch/powerpc/platforms/powermac/pic.c
+++ b/arch/powerpc/platforms/powermac/pic.c
@@ -459,7 +459,7 @@ void __init pmac_pic_init(void)
 			mpic_setup_cascade(irqctrler2->intrs[0].line,
 					   pmac_u3_cascade, mpic2);
 		}
-#if defined(CONFIG_XMON) && defined(CONFIG_PPC32)
+#ifdef CONFIG_XMON
 		{
 			struct device_node* pswitch;
 			int nmi_irq;
diff --git a/arch/powerpc/platforms/powermac/setup.c b/arch/powerpc/platforms/powermac/setup.c
index 3b7a492d9b6..6ee620fe519 100644
--- a/arch/powerpc/platforms/powermac/setup.c
+++ b/arch/powerpc/platforms/powermac/setup.c
@@ -77,6 +77,7 @@
 #include <asm/pmc.h>
 #include <asm/mpic.h>
 #include <asm/lmb.h>
+#include <asm/udbg.h>
 
 #include "pmac.h"
 
@@ -322,16 +323,6 @@ void __init pmac_setup_arch(void)
 	l2cr_init();
 #endif /* CONFIG_PPC32 */
 
-#ifdef CONFIG_PPC64
-	/* Probe motherboard chipset */
-	/* this is done earlier in setup_arch for 32-bit */
-	pmac_feature_init();
-
-	/* We can NAP */
-	powersave_nap = 1;
-	printk(KERN_INFO "Using native/NAP idle loop\n");
-#endif
-
 #ifdef CONFIG_KGDB
 	zs_kgdb_hook(0);
 #endif
@@ -622,13 +613,26 @@ static void __init pmac_init_early(void)
 	 * and call ioremap
 	 */
 	hpte_init_native();
+#endif
 
-	/* Init SCC */
-	if (strstr(cmd_line, "sccdbg")) {
-		sccdbg = 1;
-		udbg_init_scc(NULL);
+	/* Enable early btext debug if requested */
+	if (strstr(cmd_line, "btextdbg")) {
+		udbg_adb_init_early();
+		register_early_udbg_console();
 	}
 
+	/* Probe motherboard chipset */
+	pmac_feature_init();
+
+	/* We can NAP */
+	powersave_nap = 1;
+	printk(KERN_INFO "Using native/NAP idle loop\n");
+
+	/* Initialize debug stuff */
+	udbg_scc_init(!!strstr(cmd_line, "sccdbg"));
+	udbg_adb_init(!!strstr(cmd_line, "btextdbg"));
+
+#ifdef CONFIG_PPC64
 	/* Setup interrupt mapping options */
 	ppc64_interrupt_controller = IC_OPEN_PIC;
 
@@ -638,19 +642,8 @@ static void __init pmac_init_early(void)
 
 static void __init pmac_progress(char *s, unsigned short hex)
 {
-#ifdef CONFIG_PPC64
-	if (sccdbg) {
-		udbg_puts(s);
-		udbg_puts("\n");
-		return;
-	}
-#endif
-#ifdef CONFIG_BOOTX_TEXT
-	if (boot_text_mapped) {
-		btext_drawstring(s);
-		btext_drawchar('\n');
-	}
-#endif /* CONFIG_BOOTX_TEXT */
+	udbg_puts(s);
+	udbg_puts("\n");
 }
 
 /*
@@ -735,7 +728,8 @@ static int __init pmac_probe(int platform)
 }
 
 #ifdef CONFIG_PPC64
-static int pmac_probe_mode(struct pci_bus *bus)
+/* Move that to pci.c */
+static int pmac_pci_probe_mode(struct pci_bus *bus)
 {
 	struct device_node *node = bus->sysdata;
 
@@ -771,7 +765,7 @@ struct machdep_calls __initdata pmac_md = {
 	.check_legacy_ioport	= pmac_check_legacy_ioport,
 	.progress		= pmac_progress,
 #ifdef CONFIG_PPC64
-	.pci_probe_mode		= pmac_probe_mode,
+	.pci_probe_mode		= pmac_pci_probe_mode,
 	.idle_loop		= native_idle,
 	.enable_pmcs		= power4_enable_pmcs,
 #ifdef CONFIG_KEXEC
diff --git a/arch/powerpc/platforms/powermac/udbg_adb.c b/arch/powerpc/platforms/powermac/udbg_adb.c
new file mode 100644
index 00000000000..e51de55b2d6
--- /dev/null
+++ b/arch/powerpc/platforms/powermac/udbg_adb.c
@@ -0,0 +1,218 @@
+#include <linux/config.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/bitops.h>
+#include <linux/ptrace.h>
+#include <linux/adb.h>
+#include <linux/pmu.h>
+#include <linux/cuda.h>
+#include <asm/machdep.h>
+#include <asm/io.h>
+#include <asm/page.h>
+#include <asm/xmon.h>
+#include <asm/prom.h>
+#include <asm/bootx.h>
+#include <asm/machdep.h>
+#include <asm/errno.h>
+#include <asm/pmac_feature.h>
+#include <asm/processor.h>
+#include <asm/delay.h>
+#include <asm/btext.h>
+#include <asm/time.h>
+#include <asm/udbg.h>
+
+/*
+ * This implementation is "special", it can "patch" the current
+ * udbg implementation and work on top of it. It must thus be
+ * initialized last
+ */
+
+static void (*udbg_adb_old_putc)(char c);
+static char (*udbg_adb_old_getc)(void);
+static int (*udbg_adb_old_getc_poll)(void);
+
+static enum {
+	input_adb_none,
+	input_adb_pmu,
+	input_adb_cuda,
+} input_type = input_adb_none;
+
+static int udbg_adb_use_btext;
+
+int xmon_wants_key, xmon_adb_keycode;
+
+static inline void udbg_adb_poll(void)
+{
+#ifdef CONFIG_ADB_PMU
+	if (input_type == input_adb_pmu)
+		pmu_poll_adb();
+#endif /* CONFIG_ADB_PMU */
+#ifdef CONFIG_ADB_CUDA
+	if (input_type == input_adb_cuda)
+		cuda_poll();
+#endif /* CONFIG_ADB_CUDA */
+}
+
+#ifdef CONFIG_BOOTX_TEXT
+static int xmon_adb_shiftstate;
+
+static unsigned char xmon_keytab[128] =
+	"asdfhgzxcv\000bqwer"				/* 0x00 - 0x0f */
+	"yt123465=97-80]o"				/* 0x10 - 0x1f */
+	"u[ip\rlj'k;\\,/nm."				/* 0x20 - 0x2f */
+	"\t `\177\0\033\0\0\0\0\0\0\0\0\0\0"		/* 0x30 - 0x3f */
+	"\0.\0*\0+\0\0\0\0\0/\r\0-\0"			/* 0x40 - 0x4f */
+	"\0\0000123456789\0\0\0";			/* 0x50 - 0x5f */
+
+static unsigned char xmon_shift_keytab[128] =
+	"ASDFHGZXCV\000BQWER"				/* 0x00 - 0x0f */
+	"YT!@#$^%+(&_*)}O"				/* 0x10 - 0x1f */
+	"U{IP\rLJ\"K:|<?NM>"				/* 0x20 - 0x2f */
+	"\t ~\177\0\033\0\0\0\0\0\0\0\0\0\0"		/* 0x30 - 0x3f */
+	"\0.\0*\0+\0\0\0\0\0/\r\0-\0"			/* 0x40 - 0x4f */
+	"\0\0000123456789\0\0\0";			/* 0x50 - 0x5f */
+
+static char udbg_adb_local_getc(void)
+{
+	int k, t, on;
+
+	xmon_wants_key = 1;
+	for (;;) {
+		xmon_adb_keycode = -1;
+		t = 0;
+		on = 0;
+		k = -1;
+		do {
+			if (--t < 0) {
+				on = 1 - on;
+				btext_drawchar(on? 0xdb: 0x20);
+				btext_drawchar('\b');
+				t = 200000;
+			}
+			udbg_adb_poll();
+			if (udbg_adb_old_getc_poll)
+				k = udbg_adb_old_getc_poll();
+		} while (k == -1 && xmon_adb_keycode == -1);
+		if (on)
+			btext_drawstring(" \b");
+		if (k != -1)
+			return k;
+		k = xmon_adb_keycode;
+
+		/* test for shift keys */
+		if ((k & 0x7f) == 0x38 || (k & 0x7f) == 0x7b) {
+			xmon_adb_shiftstate = (k & 0x80) == 0;
+			continue;
+		}
+		if (k >= 0x80)
+			continue;	/* ignore up transitions */
+		k = (xmon_adb_shiftstate? xmon_shift_keytab: xmon_keytab)[k];
+		if (k != 0)
+			break;
+	}
+	xmon_wants_key = 0;
+	return k;
+}
+#endif /* CONFIG_BOOTX_TEXT */
+
+static char udbg_adb_getc(void)
+{
+#ifdef CONFIG_BOOTX_TEXT
+	if (udbg_adb_use_btext && input_type != input_adb_none)
+		return udbg_adb_local_getc();
+#endif
+	if (udbg_adb_old_getc)
+		return udbg_adb_old_getc();
+	return -1;
+}
+
+/* getc_poll() is not really used, unless you have the xmon-over modem
+ * hack that doesn't quite concern us here, thus we just poll the low level
+ * ADB driver to prevent it from timing out and call back the original poll
+ * routine.
+ */
+static int udbg_adb_getc_poll(void)
+{
+	udbg_adb_poll();
+
+	if (udbg_adb_old_getc_poll)
+		return udbg_adb_old_getc_poll();
+	return -1;
+}
+
+static void udbg_adb_putc(char c)
+{
+#ifdef CONFIG_BOOTX_TEXT
+	if (udbg_adb_use_btext)
+		btext_drawchar(c);
+#endif
+	if (udbg_adb_old_putc)
+		return udbg_adb_old_putc(c);
+}
+
+void udbg_adb_init_early(void)
+{
+#ifdef CONFIG_BOOTX_TEXT
+	if (btext_find_display(1) == 0) {
+		udbg_adb_use_btext = 1;
+		udbg_putc = udbg_adb_putc;
+	}
+#endif
+}
+
+int udbg_adb_init(int force_btext)
+{
+	struct device_node *np;
+
+	/* Capture existing callbacks */
+	udbg_adb_old_putc = udbg_putc;
+	udbg_adb_old_getc = udbg_getc;
+	udbg_adb_old_getc_poll = udbg_getc_poll;
+
+	/* Check if our early init was already called */
+	if (udbg_adb_old_putc == udbg_adb_putc ||
+	    udbg_adb_old_putc == btext_drawchar)
+		udbg_adb_old_putc = NULL;
+
+	/* Set ours as output */
+	udbg_putc = udbg_adb_putc;
+	udbg_getc = udbg_adb_getc;
+	udbg_getc_poll = udbg_adb_getc_poll;
+
+#ifdef CONFIG_BOOTX_TEXT
+	/* Check if we should use btext output */
+	if (btext_find_display(force_btext) == 0)
+		udbg_adb_use_btext = 1;
+#endif
+
+	/* See if there is a keyboard in the device tree with a parent
+	 * of type "adb". If not, we return a failure, but we keep the
+	 * bext output set for now
+	 */
+	for (np = NULL; (np = of_find_node_by_name(np, "keyboard")) != NULL;) {
+		struct device_node *parent = of_get_parent(np);
+		int found = (parent && !strcmp(parent->type, "adb") == 0);
+		of_node_put(parent);
+		if (found)
+			break;
+	}
+	if (np == NULL)
+		return -ENODEV;
+	of_node_put(np);
+
+#ifdef CONFIG_ADB_PMU
+	if (find_via_pmu())
+		input_type = input_adb_pmu;
+#endif
+#ifdef CONFIG_ADB_CUDA
+	if (find_via_cuda())
+		input_type = input_adb_cuda;
+#endif
+
+	/* Same as above: nothing found, keep btext set for output */
+	if (input_type == input_adb_none)
+		return -ENODEV;
+
+	return 0;
+}
diff --git a/arch/powerpc/platforms/powermac/udbg_scc.c b/arch/powerpc/platforms/powermac/udbg_scc.c
new file mode 100644
index 00000000000..df6dec49c4c
--- /dev/null
+++ b/arch/powerpc/platforms/powermac/udbg_scc.c
@@ -0,0 +1,165 @@
+/*
+ * udbg for for zilog scc ports as found on Apple PowerMacs
+ *
+ * Copyright (C) 2001-2005 PPC 64 Team, IBM Corp
+ *
+ *      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/config.h>
+#include <linux/types.h>
+#include <asm/udbg.h>
+#include <asm/processor.h>
+#include <asm/io.h>
+#include <asm/prom.h>
+#include <asm/pmac_feature.h>
+
+extern u8 real_readb(volatile u8 __iomem  *addr);
+extern void real_writeb(u8 data, volatile u8 __iomem *addr);
+
+#define	SCC_TXRDY	4
+#define SCC_RXRDY	1
+
+static volatile u8 __iomem *sccc;
+static volatile u8 __iomem *sccd;
+
+static void udbg_scc_putc(char c)
+{
+	if (sccc) {
+		while ((in_8(sccc) & SCC_TXRDY) == 0)
+			;
+		out_8(sccd,  c);
+		if (c == '\n')
+			udbg_scc_putc('\r');
+	}
+}
+
+static int udbg_scc_getc_poll(void)
+{
+	if (sccc) {
+		if ((in_8(sccc) & SCC_RXRDY) != 0)
+			return in_8(sccd);
+		else
+			return -1;
+	}
+	return -1;
+}
+
+static char udbg_scc_getc(void)
+{
+	if (sccc) {
+		while ((in_8(sccc) & SCC_RXRDY) == 0)
+			;
+		return in_8(sccd);
+	}
+	return 0;
+}
+
+static unsigned char scc_inittab[] = {
+    13, 0,		/* set baud rate divisor */
+    12, 0,
+    14, 1,		/* baud rate gen enable, src=rtxc */
+    11, 0x50,		/* clocks = br gen */
+    5,  0xea,		/* tx 8 bits, assert DTR & RTS */
+    4,  0x46,		/* x16 clock, 1 stop */
+    3,  0xc1,		/* rx enable, 8 bits */
+};
+
+void udbg_scc_init(int force_scc)
+{
+	u32 *reg;
+	unsigned long addr;
+	struct device_node *stdout = NULL, *escc = NULL, *macio = NULL;
+	struct device_node *ch, *ch_def = NULL, *ch_a = NULL;
+	char *path;
+	int i, x;
+
+	escc = of_find_node_by_name(NULL, "escc");
+	if (escc == NULL)
+		goto bail;
+	macio = of_get_parent(escc);
+	if (macio == NULL)
+		goto bail;
+	path = (char *)get_property(of_chosen, "linux,stdout-path", NULL);
+	if (path != NULL)
+		stdout = of_find_node_by_path(path);
+	for (ch = NULL; (ch = of_get_next_child(escc, ch)) != NULL;) {
+		if (ch == stdout)
+			ch_def = of_node_get(ch);
+		if (strcmp(ch->name, "ch-a") == 0)
+			ch_a = of_node_get(ch);
+	}
+	if (ch_def == NULL && !force_scc)
+		goto bail;
+
+	ch = ch_def ? ch_def : ch_a;
+
+	/* Get address within mac-io ASIC */
+	reg = (u32 *)get_property(escc, "reg", NULL);
+	if (reg == NULL)
+		goto bail;
+	addr = reg[0];
+
+	/* Get address of mac-io PCI itself */
+	reg = (u32 *)get_property(macio, "assigned-addresses", NULL);
+	if (reg == NULL)
+		goto bail;
+	addr += reg[2];
+
+	/* Lock the serial port */
+	pmac_call_feature(PMAC_FTR_SCC_ENABLE, ch,
+			  PMAC_SCC_ASYNC | PMAC_SCC_FLAG_XMON, 1);
+
+
+	/* Setup for 57600 8N1 */
+	if (ch == ch_a)
+		addr += 0x20;
+	sccc = (volatile u8 * __iomem) ioremap(addr & PAGE_MASK, PAGE_SIZE) ;
+	sccc += addr & ~PAGE_MASK;
+	sccd = sccc + 0x10;
+
+	mb();
+
+	for (i = 20000; i != 0; --i)
+		x = in_8(sccc);
+	out_8(sccc, 0x09);		/* reset A or B side */
+	out_8(sccc, 0xc0);
+	for (i = 0; i < sizeof(scc_inittab); ++i)
+		out_8(sccc, scc_inittab[i]);
+
+	udbg_putc = udbg_scc_putc;
+	udbg_getc = udbg_scc_getc;
+	udbg_getc_poll = udbg_scc_getc_poll;
+
+	udbg_puts("Hello World !\n");
+
+ bail:
+	of_node_put(macio);
+	of_node_put(escc);
+	of_node_put(stdout);
+	of_node_put(ch_def);
+	of_node_put(ch_a);
+}
+
+#ifdef CONFIG_PPC64
+static void udbg_real_scc_putc(char c)
+{
+	while ((real_readb(sccc) & SCC_TXRDY) == 0)
+		;
+	real_writeb(c, sccd);
+	if (c == '\n')
+		udbg_real_scc_putc('\r');
+}
+
+void udbg_init_pmac_realmode(void)
+{
+	sccc = (volatile u8 __iomem *)0x80013020ul;
+	sccd = (volatile u8 __iomem *)0x80013030ul;
+
+	udbg_putc = udbg_real_scc_putc;
+	udbg_getc = NULL;
+	udbg_getc_poll = NULL;
+}
+#endif /* CONFIG_PPC64 */