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/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;