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>

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index eb70c2d..d5acb9e 100644 (file)
--- 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 7636432..70a9578 100644 (file)
--- 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 8c08d7d..1bed3cb 100644 (file)
--- 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)