arm64: mvebu: Add basic support for the Marvell Armada 7K/8K SoC

Compared to the Armada 3700, the Armada 7K and 8K are much more on the
high-end side: they use a dual Cortex-A72 or a quad Cortex-A72, as
opposed to the Cortex-A53 for the Armada 3700.

The Armada 7K and 8K also use a fairly unique architecture, internally
they are composed of several components:

- One AP (Application Processor), which contains the processor itself
  and a few core hardware blocks. The AP used in the Armada 7K and 8K
  is called AP806, and is available in two configurations:
  dual Cortex-A72 and quad Cortex-A72.
- One or two CP (Communication Processor), which contain most of the I/O
  interfaces (SATA, PCIe, Ethernet, etc.). The 7K family chips have one
  CP, while the 8K family chips integrate two CPs, providing two times
  the number of I/O interfaces available in the CP.
  The CP used in the 7K and 8K is called CP110.

All in all, this gives the following combinations:

- Armada 7020, which is a dual Cortex-A72 with one CP
- Armada 7040, which is a quad Cortex-A72 with one CP
- Armada 8020, which is a dual Cortex-A72 with two CPs
- Armada 8040, which is a quad Cortex-A72 with two CPs

This patch adds basic support for this ARMv8 based SoC into U-Boot.
Future patches will integrate other device drivers and board support,
starting with the Marvell DB-88F7040 development board.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Nadav Haklai <nadavh@marvell.com>
Cc: Neta Zur Hershkovits <neta@marvell.com>
Cc: Kostya Porotchkin <kostap@marvell.com>
Cc: Omri Itach <omrii@marvell.com>
Cc: Igal Liberman <igall@marvell.com>
Cc: Haim Boot <hayim@marvell.com>
Cc: Hanna Hawa <hannah@marvell.com>
diff --git a/arch/arm/mach-mvebu/arm64-common.c b/arch/arm/mach-mvebu/arm64-common.c
new file mode 100644
index 0000000..7055a81
--- /dev/null
+++ b/arch/arm/mach-mvebu/arm64-common.c
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2016 Stefan Roese <sr@denx.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <fdtdec.h>
+#include <libfdt.h>
+#include <asm/io.h>
+#include <asm/system.h>
+#include <asm/arch/cpu.h>
+#include <asm/arch/soc.h>
+#include <asm/armv8/mmu.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/*
+ * On ARMv8, MBus is not configured in U-Boot. To enable compilation
+ * of the already implemented drivers, lets add a dummy version of
+ * this function so that linking does not fail.
+ */
+const struct mbus_dram_target_info *mvebu_mbus_dram_info(void)
+{
+	return NULL;
+}
+
+/* DRAM init code ... */
+
+static const void *get_memory_reg_prop(const void *fdt, int *lenp)
+{
+	int offset;
+
+	offset = fdt_path_offset(fdt, "/memory");
+	if (offset < 0)
+		return NULL;
+
+	return fdt_getprop(fdt, offset, "reg", lenp);
+}
+
+int dram_init(void)
+{
+	const void *fdt = gd->fdt_blob;
+	const fdt32_t *val;
+	int ac, sc, len;
+
+	ac = fdt_address_cells(fdt, 0);
+	sc = fdt_size_cells(fdt, 0);
+	if (ac < 0 || sc < 1 || sc > 2) {
+		printf("invalid address/size cells\n");
+		return -EINVAL;
+	}
+
+	val = get_memory_reg_prop(fdt, &len);
+	if (len / sizeof(*val) < ac + sc)
+		return -EINVAL;
+
+	val += ac;
+
+	gd->ram_size = fdtdec_get_number(val, sc);
+
+	debug("DRAM size = %08lx\n", (unsigned long)gd->ram_size);
+
+	return 0;
+}
+
+void dram_init_banksize(void)
+{
+	const void *fdt = gd->fdt_blob;
+	const fdt32_t *val;
+	int ac, sc, cells, len, i;
+
+	val = get_memory_reg_prop(fdt, &len);
+	if (len < 0)
+		return;
+
+	ac = fdt_address_cells(fdt, 0);
+	sc = fdt_size_cells(fdt, 0);
+	if (ac < 1 || sc > 2 || sc < 1 || sc > 2) {
+		printf("invalid address/size cells\n");
+		return;
+	}
+
+	cells = ac + sc;
+
+	len /= sizeof(*val);
+
+	for (i = 0; i < CONFIG_NR_DRAM_BANKS && len >= cells;
+	     i++, len -= cells) {
+		gd->bd->bi_dram[i].start = fdtdec_get_number(val, ac);
+		val += ac;
+		gd->bd->bi_dram[i].size = fdtdec_get_number(val, sc);
+		val += sc;
+
+		debug("DRAM bank %d: start = %08lx, size = %08lx\n",
+		      i, (unsigned long)gd->bd->bi_dram[i].start,
+		      (unsigned long)gd->bd->bi_dram[i].size);
+	}
+}
+
+int arch_cpu_init(void)
+{
+	/* Nothing to do (yet) */
+	return 0;
+}
+
+int arch_early_init_r(void)
+{
+	struct udevice *dev;
+	int ret;
+
+	/* Call the comphy code via the MISC uclass driver */
+	ret = uclass_get_device(UCLASS_MISC, 0, &dev);
+	if (ret) {
+		debug("COMPHY init failed: %d\n", ret);
+		return -ENODEV;
+	}
+
+	/* Cause the SATA device to do its early init */
+	uclass_first_device(UCLASS_AHCI, &dev);
+
+	return 0;
+}