This patch adds support for the MHU mailbox peripheral used on Juno by
application processors to communicate with remote SCP handling most of
the CPU/system power management. It also adds the SRAM reserving the
shared memory and SCPI message protocol using that shared memory.

Cc: Liviu Dudau <Liviu.Dudau@arm.com>
Cc: Jon Medhurst (Tixy) <redacted>
Signed-off-by: Sudeep Holla <redacted>
---
 arch/arm64/boot/dts/arm/juno-base.dtsi   | 31 +++++++++++++++++++++++++++++++
 arch/arm64/boot/dts/arm/juno-clocks.dtsi | 23 +++++++++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/arch/arm64/boot/dts/arm/juno-base.dtsi b/arch/arm64/boot/dts/arm/juno-base.dtsi
index e3ee96036eca..f8069a98da25 100644
--- a/arch/arm64/boot/dts/arm/juno-base.dtsi
+++ b/arch/arm64/boot/dts/arm/juno-base.dtsi

@@ -17,6 +17,18 @@
 		};
 	};
 
+	mailbox: mhu at 2b1f0000 {
+		compatible = "arm,mhu", "arm,primecell";
+		reg = <0x0 0x2b1f0000 0x0 0x1000>;
+		interrupts = <GIC_SPI 36 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 35 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-names = "mhu_lpri_rx",
+				  "mhu_hpri_rx";
+		#mbox-cells = <1>;
+		clocks = <&soc_refclk100mhz>;
+		clock-names = "apb_pclk";
+	};
+
 	gic: interrupt-controller at 2c010000 {
 		compatible = "arm,gic-400", "arm,cortex-a15-gic";
 		reg = <0x0 0x2c010000 0 0x1000>,

@@ -44,6 +56,25 @@
 			     <GIC_PPI 10 (GIC_CPU_MASK_SIMPLE(6) | IRQ_TYPE_LEVEL_LOW)>;
 	};
 
+	sram: sram at 2e000000 {
+		compatible = "arm,juno-sram-ns", "mmio-sram";
+		reg = <0x0 0x2e000000 0x0 0x8000>;
+
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges = <0 0x0 0x2e000000 0x8000>;
+
+		cpu_scp_lpri: scp-shmem at 0 {
+			compatible = "arm,juno-scp-shmem";
+			reg = <0x0 0x200>;
+		};
+
+		cpu_scp_hpri: scp-shmem at 200 {
+			compatible = "arm,juno-scp-shmem";
+			reg = <0x200 0x200>;
+		};
+	};
+
 	/include/ "juno-clocks.dtsi"
 
 	dma at 7ff00000 {

diff --git a/arch/arm64/boot/dts/arm/juno-clocks.dtsi b/arch/arm64/boot/dts/arm/juno-clocks.dtsi
index 25352ed943e6..64af7370815a 100644
--- a/arch/arm64/boot/dts/arm/juno-clocks.dtsi
+++ b/arch/arm64/boot/dts/arm/juno-clocks.dtsi

@@ -42,3 +42,26 @@
 		clock-frequency = <400000000>;
 		clock-output-names = "faxi_clk";
 	};
+
+	scpi {
+		compatible = "arm,scpi";
+		mboxes = <&mailbox 1>;
+		shmem = <&cpu_scp_hpri>;
+
+		clocks {
+			compatible = "arm,scpi-clocks";
+
+			scpi_dvfs: scpi_clocks at 0 {
+				compatible = "arm,scpi-dvfs-clocks";
+				#clock-cells = <1>;
+				clock-indices = <0>, <1>, <2>;
+				clock-output-names = "vbig", "vlittle", "vgpu";
+			};
+			scpi_clk: scpi_clocks at 3 {
+				compatible = "arm,scpi-variable-clocks";
+				#clock-cells = <1>;
+				clock-indices = <3>, <4>;