arm: bcmbca: add bcm6858 SoC support under CONFIG_ARCH_BCMBCA

BCM6858 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_BCM6858 chip config and
CONFIG_ARCH_BCMBCA platform config.

This initial support includes a bare-bone implementation and the
original dts is updated with the one from linux next git repository.

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/bcm6858/mmu_table.c b/arch/arm/mach-bcmbca/bcm6858/mmu_table.c
new file mode 100644
index 0000000..8982910
--- /dev/null
+++ b/arch/arm/mach-bcmbca/bcm6858/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 bcm96858_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 = bcm96858_mem_map;