[PATCH 1/2] ARM: dts: da850-lego-ev3: Add node for reboot modes

[David Lechner]

This adds a new node for reboot modes on LEGO MINDSTORMS EV3. The EV3's
bootloader looks for a magic number in the ARM local RAM and if found,
it will boot into a special firmware update mode where the flash memory
can be written via USB.

This has been testing working using the command:

    # systemctl reboot loader

Signed-off-by: David Lechner <da...@lechnology.com>
---
 arch/arm/boot/dts/da850-lego-ev3.dts | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/arch/arm/boot/dts/da850-lego-ev3.dts 
b/arch/arm/boot/dts/da850-lego-ev3.dts
index e4bbf48..1cb2ff1 100644
--- a/arch/arm/boot/dts/da850-lego-ev3.dts
+++ b/arch/arm/boot/dts/da850-lego-ev3.dts
@@ -212,6 +212,23 @@
                compatible = "gpio-backlight";
                gpios = <&gpio 44 GPIO_ACTIVE_HIGH>;
        };
+
+       /* ARM local RAM */
+       memory@ffff0000 {
+               compatible = "syscon", "simple-mfd";
+               reg = <0xffff0000 0x2000>; /* 8k */
+
+               /*
+                * The I2C bootloader looks for this magic value to either
+                * boot normally or boot into a firmware update mode.
+                */
+               reboot-mode {
+                       compatible = "syscon-reboot-mode";
+                       offset = <0x1ffc>;
+                       mode-normal = <0x00000000>;
+                       mode-loader = <0x5555aaaa>;
+               };
+       };
 };
 
 &cpu {
-- 
2.7.4