[PATCH 2/4] ARM: rockchip: add sram dt nodes and documentation

[heiko@sntech.de (Heiko Stübner)]

The Rockchip SoCs need a special part of their sram for bringup
of additional cores. Therefore the mapped area should be split
into a special area for the smp code and a generic area that gets
handled by mmio-sram.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
 .../devicetree/bindings/arm/rockchip/smp-sram.txt  |   29 ++++++++++++++++++++
 arch/arm/boot/dts/rk3066a.dtsi                     |   14 ++++++++++
 2 files changed, 43 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/rockchip/smp-sram.txt

diff --git a/Documentation/devicetree/bindings/arm/rockchip/smp-sram.txt b/Documentation/devicetree/bindings/arm/rockchip/smp-sram.txt
new file mode 100644
index 0000000..9c81fac
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/rockchip/smp-sram.txt
@@ -0,0 +1,29 @@
+Rockchip SRAM for smp bringup:
+------------------------------
+
+Rockchip smp-capable SoCs use the first part of the sram for the bringup
+of the cores. Once the core gets powered up it executes the code that is
+residing at the very beginning of the sram.
+
+While the suspend also needs to have code in the sram that can be realized
+with the generic mmio-sram driver and only the smp specific part needs to
+be mapped specially in the smp code.
+
+Therefore split the sram mapping in a smp-specific part that gets used
+by the smp code exclusively and a bigger generic part for mmio-sram
+
+Required node properties:
+- compatible value : = "rockchip,rk3066-smp-sram";
+- reg : physical base address and the size of the registers window
+
+Example:
+
+	sram at 10080000 {
+		compatible = "rockchip,rk3066-smp-sram";
+		reg = <0x10080000 0x100>;
+	};
+
+	sram: sram at 10080100 {
+		compatible = "mmio-sram";
+		reg = <0x10080100 0x9900>;
+	};
diff --git a/arch/arm/boot/dts/rk3066a.dtsi b/arch/arm/boot/dts/rk3066a.dtsi
index 26c4311..44eabd2 100644
--- a/arch/arm/boot/dts/rk3066a.dtsi
+++ b/arch/arm/boot/dts/rk3066a.dtsi
@@ -53,6 +53,20 @@
 			reg = <0x1013c000 0x100>;
 		};
 
+		/*
+		 * the first part of the sram is needed for the smp
+		 * trampoline code during cpu bringup
+		 */
+		sram at 10080000 {
+			compatible = "rockchip,rk3066-smp-sram";
+			reg = <0x10080000 0x100>;
+		};
+
+		sram: sram at 10080100 {
+			compatible = "mmio-sram";
+			reg = <0x10080100 0x9900>;
+		};
+
 		gic: interrupt-controller at 1013d000 {
 			compatible = "arm,cortex-a9-gic";
 			interrupt-controller;
-- 
1.7.10.4