From 6ec127fb3c7754d3dc6614e9744386fbe652927f Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton@imgtec.com>
Date: Sun, 24 May 2015 16:11:42 +0100
Subject: [PATCH] MIPS: JZ4740: only detect RAM size if not specified in DT

Allow a devicetree to specify the memory present in the system rather
than probing it from the memory controller. This both saves the probing
for systems where the amount of memory is fixed, and will simplify the
bringup of later Ingenic SoCs where the memory controller register
layout differs.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10163/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/Kconfig         | 1 +
 arch/mips/jz4740/Makefile | 2 ++
 arch/mips/jz4740/setup.c  | 8 +++++++-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index eb70c2d0a6a9..d5acb9e96d59 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -302,6 +302,7 @@ config MACH_INGENIC
 	select GENERIC_IRQ_CHIP
 	select BUILTIN_DTB
 	select USE_OF
+	select LIBFDT
 
 config LANTIQ
 	bool "Lantiq based platforms"
diff --git a/arch/mips/jz4740/Makefile b/arch/mips/jz4740/Makefile
index 7636432af6ee..70a9578cc6db 100644
--- a/arch/mips/jz4740/Makefile
+++ b/arch/mips/jz4740/Makefile
@@ -7,6 +7,8 @@
 obj-y += prom.o time.o reset.o setup.o \
 	gpio.o platform.o timer.o serial.o
 
+CFLAGS_setup.o = -I$(src)/../../../scripts/dtc/libfdt
+
 # board specific support
 
 obj-$(CONFIG_JZ4740_QI_LB60)	+= board-qi_lb60.o
diff --git a/arch/mips/jz4740/setup.c b/arch/mips/jz4740/setup.c
index 8c08d7dcda66..1bed3cb062b3 100644
--- a/arch/mips/jz4740/setup.c
+++ b/arch/mips/jz4740/setup.c
@@ -18,6 +18,7 @@
 #include <linux/io.h>
 #include <linux/irqchip.h>
 #include <linux/kernel.h>
+#include <linux/libfdt.h>
 #include <linux/of_fdt.h>
 #include <linux/of_platform.h>
 
@@ -55,9 +56,14 @@ static void __init jz4740_detect_mem(void)
 
 void __init plat_mem_setup(void)
 {
+	int offset;
+
 	jz4740_reset_init();
-	jz4740_detect_mem();
 	__dt_setup_arch(__dtb_start);
+
+	offset = fdt_path_offset(__dtb_start, "/memory");
+	if (offset < 0)
+		jz4740_detect_mem();
 }
 
 void __init device_tree_init(void)
-- 
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