arm: bcmbca: add bcm6856 SoC support under CONFIG_ARCH_BCMBCA

BCM6856 is a Broadcom B53 based PON Gateway SoC. It is part of the BCA
(Broadband Carrier Access origin) chipset family. Like other Broadband
SoC, this patch adds it under CONFIG_BCM6856 chip config and
CONFIG_ARCH_BCMBCA platform config.

This initial support includes a bare-bone implementation and dts with
CPU subsystem, memory and Broadcom 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 to the console.

Signed-off-by: William Zhang <william.zhang@broadcom.com>
Reviewed-by: Philippe Reynes <philippe.reynes@softathome.com>
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index a69141d..1fb8f83 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -1199,6 +1199,8 @@
 	bcm96813.dtb
 dtb-$(CONFIG_BCM6846) += \
 	bcm96846.dtb
+dtb-$(CONFIG_BCM6856) += \
+	bcm96856.dtb
 dtb-$(CONFIG_BCM6878) += \
 	bcm96878.dtb
 
diff --git a/arch/arm/dts/bcm6856.dtsi b/arch/arm/dts/bcm6856.dtsi
new file mode 100644
index 0000000..0bce649
--- /dev/null
+++ b/arch/arm/dts/bcm6856.dtsi
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright 2022 Broadcom Ltd.
+ */
+
+#include <dt-bindings/interrupt-controller/irq.h>
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
+/ {
+	compatible = "brcm,bcm6856", "brcm,bcmbca";
+	#address-cells = <2>;
+	#size-cells = <2>;
+
+	interrupt-parent = <&gic>;
+
+	cpus {
+		#address-cells = <2>;
+		#size-cells = <0>;
+
+		B53_0: cpu@0 {
+			compatible = "brcm,brahma-b53";
+			device_type = "cpu";
+			reg = <0x0 0x0>;
+			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+		};
+
+		B53_1: cpu@1 {
+			compatible = "brcm,brahma-b53";
+			device_type = "cpu";
+			reg = <0x0 0x1>;
+			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+		};
+
+		L2_0: l2-cache0 {
+			compatible = "cache";
+		};
+	};
+
+	timer {
+		compatible = "arm,armv8-timer";
+		interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_LEVEL_LOW)>,
+			<GIC_PPI 14 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_LEVEL_LOW)>,
+			<GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_LEVEL_LOW)>,
+			<GIC_PPI 10 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_LEVEL_LOW)>;
+	};
+
+	pmu: pmu {
+		compatible = "arm,cortex-a53-pmu";
+		interrupts = <GIC_SPI 9 IRQ_TYPE_LEVEL_HIGH>,
+			<GIC_SPI 10 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-affinity = <&B53_0>, <&B53_1>;
+	};
+
+	clocks: clocks {
+		periph_clk:periph-clk {
+			compatible = "fixed-clock";
+			#clock-cells = <0>;
+			clock-frequency = <200000000>;
+		};
+	};
+
+	psci {
+		compatible = "arm,psci-0.2";
+		method = "smc";
+	};
+
+	axi@81000000 {
+		compatible = "simple-bus";
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges = <0x0 0x0 0x81000000 0x8000>;
+
+		gic: interrupt-controller@1000 {
+			compatible = "arm,gic-400";
+			#interrupt-cells = <3>;
+			interrupt-controller;
+			reg = <0x1000 0x1000>, /* GICD */
+				<0x2000 0x2000>, /* GICC */
+				<0x4000 0x2000>, /* GICH */
+				<0x6000 0x2000>; /* GICV */
+			interrupts = <GIC_PPI 9 (GIC_CPU_MASK_SIMPLE(2) |
+					IRQ_TYPE_LEVEL_HIGH)>;
+		};
+	};
+
+	bus@ff800000 {
+		compatible = "simple-bus";
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges = <0x0 0x0 0xff800000 0x800000>;
+
+		uart0: serial@640 {
+			compatible = "brcm,bcm6345-uart";
+			reg = <0x640 0x18>;
+			interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&periph_clk>;
+			clock-names = "refclk";
+			status = "disabled";
+		};
+	};
+};
diff --git a/arch/arm/dts/bcm96856.dts b/arch/arm/dts/bcm96856.dts
new file mode 100644
index 0000000..032aeb7
--- /dev/null
+++ b/arch/arm/dts/bcm96856.dts
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright 2022 Broadcom Ltd.
+ */
+
+/dts-v1/;
+
+#include "bcm6856.dtsi"
+
+/ {
+	model = "Broadcom BCM96856 Reference Board";
+	compatible = "brcm,bcm96856", "brcm,bcm6856", "brcm,bcmbca";
+
+	aliases {
+		serial0 = &uart0;
+	};
+
+	chosen {
+		stdout-path = "serial0:115200n8";
+	};
+
+	memory@0 {
+		device_type = "memory";
+		reg = <0x0 0x0 0x0 0x08000000>;
+	};
+};
+
+&uart0 {
+	status = "okay";
+};
diff --git a/arch/arm/mach-bcmbca/Kconfig b/arch/arm/mach-bcmbca/Kconfig
index d786188..f35f02c 100644
--- a/arch/arm/mach-bcmbca/Kconfig
+++ b/arch/arm/mach-bcmbca/Kconfig
@@ -83,6 +83,16 @@
 	select DM_SERIAL
 	select BCM6345_SERIAL
 
+config BCM6856
+	bool "Support for Broadcom 6856 Family"
+	select ARM64
+	select SYS_ARCH_TIMER
+	select DM_SERIAL
+	select BCM6345_SERIAL
+	help
+	  Broadcom BCM6856 is a dual core Brahma-B53 ARMv8 based xPON Gateway
+	  SoC. This SoC family includes BCM6856, BCM6836 and BCM4910.
+
 config BCM6878
 	bool "Support for Broadcom 6878 Family"
 	select SYS_ARCH_TIMER
@@ -101,6 +111,7 @@
 source "arch/arm/mach-bcmbca/bcm6756/Kconfig"
 source "arch/arm/mach-bcmbca/bcm6813/Kconfig"
 source "arch/arm/mach-bcmbca/bcm6846/Kconfig"
+source "arch/arm/mach-bcmbca/bcm6856/Kconfig"
 source "arch/arm/mach-bcmbca/bcm6878/Kconfig"
 
 endif
diff --git a/arch/arm/mach-bcmbca/Makefile b/arch/arm/mach-bcmbca/Makefile
index e5df60e..20f8275 100644
--- a/arch/arm/mach-bcmbca/Makefile
+++ b/arch/arm/mach-bcmbca/Makefile
@@ -14,4 +14,5 @@
 obj-$(CONFIG_BCM6756) += bcm6756/
 obj-$(CONFIG_BCM6813) += bcm6813/
 obj-$(CONFIG_BCM6846) += bcm6846/
+obj-$(CONFIG_BCM6856) += bcm6856/
 obj-$(CONFIG_BCM6878) += bcm6878/
diff --git a/arch/arm/mach-bcmbca/bcm6856/Kconfig b/arch/arm/mach-bcmbca/bcm6856/Kconfig
new file mode 100644
index 0000000..6ac75cb
--- /dev/null
+++ b/arch/arm/mach-bcmbca/bcm6856/Kconfig
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# (C) Copyright 2022 Broadcom Ltd
+#
+
+if BCM6856
+
+config TARGET_BCM96856
+	bool "Broadcom 6856 Reference Board"
+	depends on ARCH_BCMBCA
+
+config SYS_SOC
+	default "bcm6856"
+
+source "board/broadcom/bcmbca/Kconfig"
+
+endif
diff --git a/arch/arm/mach-bcmbca/bcm6856/Makefile b/arch/arm/mach-bcmbca/bcm6856/Makefile
new file mode 100644
index 0000000..6262497
--- /dev/null
+++ b/arch/arm/mach-bcmbca/bcm6856/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# (C) Copyright 2022 Broadcom Ltd
+#
+obj-y += mmu_table.o
diff --git a/arch/arm/mach-bcmbca/bcm6856/mmu_table.c b/arch/arm/mach-bcmbca/bcm6856/mmu_table.c
new file mode 100644
index 0000000..8e53b49
--- /dev/null
+++ b/arch/arm/mach-bcmbca/bcm6856/mmu_table.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  Copyright 2022 Broadcom Ltd.
+ */
+#include <common.h>
+#include <asm/armv8/mmu.h>
+#include <linux/sizes.h>
+
+static struct mm_region bcm96856_mem_map[] = {
+		{
+				.virt = 0x00000000UL,
+				.phys = 0x00000000UL,
+				.size = 1UL * SZ_1G,
+				.attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) |
+						PTE_BLOCK_INNER_SHARE
+		},
+		{
+				/* SoC peripheral */
+				.virt = 0xff800000UL,
+				.phys = 0xff800000UL,
+				.size = 0x100000,
+				.attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRNE) |
+						PTE_BLOCK_NON_SHARE |
+						PTE_BLOCK_PXN | PTE_BLOCK_UXN
+		},
+		{
+				/* List terminator */
+				0,
+		}
+};
+
+struct mm_region *mem_map = bcm96856_mem_map;