arm: bcmbca: add bcm6756 SoC support

BCM6756 is an ARM A7 based WLAN Gateway and Access Point Broadband SoC.
It is part of the BCA(Broadband Carrier Access origin) chipset family so
it's added under ARCH_BCMBCA platform. This initial support includes a
bare-bone implementation and dts with CPU subsystem, memory and ARM
PL011 uart.

This SoC is supported in the linux-next git repository so the dts and
dtsi files are copied from linux.

The u-boot image can be loaded from flash or network to the entry
point address in the memory and boot from there.

Signed-off-by: William Zhang <william.zhang@broadcom.com>
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index d0996a1..2545575 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -1184,6 +1184,8 @@
 	bcm947622.dtb
 dtb-$(CONFIG_BCM63178) += \
 	bcm963178.dtb
+dtb-$(CONFIG_BCM6756) += \
+	bcm96756.dtb
 dtb-$(CONFIG_BCM6846) += \
 	bcm96846.dtb
 dtb-$(CONFIG_BCM6878) += \
diff --git a/arch/arm/dts/bcm6756.dtsi b/arch/arm/dts/bcm6756.dtsi
new file mode 100644
index 0000000..ce1b59f
--- /dev/null
+++ b/arch/arm/dts/bcm6756.dtsi
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright 2022 Broadcom Ltd.
+ */
+
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+#include <dt-bindings/interrupt-controller/irq.h>
+
+/ {
+	compatible = "brcm,bcm6756", "brcm,bcmbca";
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	interrupt-parent = <&gic>;
+
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		CA7_0: cpu@0 {
+			device_type = "cpu";
+			compatible = "arm,cortex-a7";
+			reg = <0x0>;
+			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+		};
+
+		CA7_1: cpu@1 {
+			device_type = "cpu";
+			compatible = "arm,cortex-a7";
+			reg = <0x1>;
+			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+		};
+
+		CA7_2: cpu@2 {
+			device_type = "cpu";
+			compatible = "arm,cortex-a7";
+			reg = <0x2>;
+			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+		};
+
+		CA7_3: cpu@3 {
+			device_type = "cpu";
+			compatible = "arm,cortex-a7";
+			reg = <0x3>;
+			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+		};
+
+		L2_0: l2-cache0 {
+			compatible = "cache";
+		};
+	};
+
+	timer {
+		compatible = "arm,armv7-timer";
+		interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+			<GIC_PPI 14 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+			<GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+			<GIC_PPI 10 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>;
+		arm,cpu-registers-not-fw-configured;
+	};
+
+	pmu: pmu {
+		compatible = "arm,cortex-a7-pmu";
+		interrupts = <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
+			<GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>,
+			<GIC_SPI 9 IRQ_TYPE_LEVEL_HIGH>,
+			<GIC_SPI 10 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-affinity = <&CA7_0>, <&CA7_1>,
+			<&CA7_2>, <&CA7_3>;
+	};
+
+	clocks: clocks {
+		periph_clk: periph-clk {
+			compatible = "fixed-clock";
+			#clock-cells = <0>;
+			clock-frequency = <200000000>;
+		};
+
+		uart_clk: uart-clk {
+			compatible = "fixed-factor-clock";
+			#clock-cells = <0>;
+			clocks = <&periph_clk>;
+			clock-div = <4>;
+			clock-mult = <1>;
+		};
+	};
+
+	psci {
+		compatible = "arm,psci-0.2";
+		method = "smc";
+	};
+
+	axi@81000000 {
+		compatible = "simple-bus";
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges = <0 0x81000000 0x8000>;
+
+		gic: interrupt-controller@1000 {
+			compatible = "arm,cortex-a7-gic";
+			#interrupt-cells = <3>;
+			interrupt-controller;
+			interrupts = <GIC_PPI 9 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_HIGH)>;
+			reg = <0x1000 0x1000>,
+				<0x2000 0x2000>,
+				<0x4000 0x2000>,
+				<0x6000 0x2000>;
+		};
+	};
+
+	bus@ff800000 {
+		compatible = "simple-bus";
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges = <0 0xff800000 0x800000>;
+
+		uart0: serial@12000 {
+			compatible = "arm,pl011", "arm,primecell";
+			reg = <0x12000 0x1000>;
+			interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&uart_clk>, <&uart_clk>;
+			clock-names = "uartclk", "apb_pclk";
+			status = "disabled";
+		};
+	};
+};
diff --git a/arch/arm/dts/bcm96756.dts b/arch/arm/dts/bcm96756.dts
new file mode 100644
index 0000000..9a4a87b
--- /dev/null
+++ b/arch/arm/dts/bcm96756.dts
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright 2019 Broadcom Ltd.
+ */
+
+/dts-v1/;
+
+#include "bcm6756.dtsi"
+
+/ {
+	model = "Broadcom BCM96756 Reference Board";
+	compatible = "brcm,bcm96756", "brcm,bcm6756", "brcm,bcmbca";
+
+	aliases {
+		serial0 = &uart0;
+	};
+
+	chosen {
+		stdout-path = "serial0:115200n8";
+	};
+
+	memory@0 {
+		device_type = "memory";
+		reg = <0x0 0x08000000>;
+	};
+};
+
+&uart0 {
+	status = "okay";
+};