[PATCH v3 2/6] powerpc/44x: allow override to hard-coded uart address

[Dave Kleikamp <shaggy@linux.vnet.ibm.com>]

Allow the early debug uart address to be overridden from the kernel
command line.

I would have preferred use the uart's virtual-reg property, but the device
tree hasn't been unflatted yet, and I don't know a reliable way to find it.

Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/kernel/udbg_16550.c |   17 ++++++++++++++---
 1 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c
index b4b167b..d36021a 100644
--- a/arch/powerpc/kernel/udbg_16550.c
+++ b/arch/powerpc/kernel/udbg_16550.c
@@ -219,6 +219,19 @@ void udbg_init_pas_realmode(void)
 #ifdef CONFIG_PPC_EARLY_DEBUG_44x
 #include <platforms/44x/44x.h>
 
+static unsigned long udbg_44x_comport = PPC44x_EARLY_DEBUG_VIRTADDR;
+
+static int __init early_parse_comport(char *p)
+{
+	if (!p || !(*p))
+		return 0;
+
+	udbg_44x_comport = simple_strtoul(p, 0, 16);
+
+	return 0;
+}
+early_param("uart_addr", early_parse_comport);
+
 static void udbg_44x_as1_flush(void)
 {
 	if (udbg_comport) {
@@ -249,9 +262,7 @@ static int udbg_44x_as1_getc(void)
 
 void __init udbg_init_44x_as1(void)
 {
-	udbg_comport =
-		(struct NS16550 __iomem *)PPC44x_EARLY_DEBUG_VIRTADDR;
-
+	udbg_comport = (struct NS16550 __iomem *)udbg_44x_comport;
 	udbg_putc = udbg_44x_as1_putc;
 	udbg_flush = udbg_44x_as1_flush;
 	udbg_getc = udbg_44x_as1_getc;
-- 
1.7.3.4