allwinner: Introduce basic platform support

This platform supports Allwinner's SoCs with ARMv8 cores. So far they
all sport a single cluster of Cortex-A53 cores.

"sunxi" is the original code name used for this platform, and since it
appears in the Linux kernel and in U-Boot as well, we use it here as a
short file name prefix and for identifiers.

This port includes BL31 support only. U-Boot's SPL takes the role of the
primary loader, also doing the DRAM initialization. It then loads the
rest of the firmware, namely ATF and U-Boot (BL33), then hands execution
over to ATF.

This commit includes the basic platform code shared across all SoCs.
There is no platform.mk yet.

[Andre: moved files into proper directories, supported RESET_TO_BL31,
	various clean ups and simplifications ]

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/plat/allwinner/common/sunxi_common.c b/plat/allwinner/common/sunxi_common.c
new file mode 100644
index 0000000..e36c8b0
--- /dev/null
+++ b/plat/allwinner/common/sunxi_common.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <platform.h>
+#include <platform_def.h>
+#include <sunxi_def.h>
+#include <xlat_tables_v2.h>
+
+static mmap_region_t sunxi_mmap[PLATFORM_MMAP_REGIONS + 1] = {
+	MAP_REGION_FLAT(SUNXI_ROM_BASE, SUNXI_ROM_SIZE,
+			MT_MEMORY | MT_RO | MT_SECURE),
+	MAP_REGION_FLAT(SUNXI_SRAM_BASE, SUNXI_SRAM_SIZE,
+			MT_MEMORY | MT_RW | MT_SECURE),
+	MAP_REGION_FLAT(SUNXI_DEV_BASE, SUNXI_DEV_SIZE,
+			MT_DEVICE | MT_RW | MT_SECURE),
+	MAP_REGION_FLAT(SUNXI_DRAM_BASE, SUNXI_DRAM_SIZE,
+			MT_MEMORY | MT_RW | MT_NS),
+	{},
+};
+
+unsigned int plat_get_syscnt_freq2(void)
+{
+	return SUNXI_OSC24M_CLK_IN_HZ;
+}
+
+uintptr_t plat_get_ns_image_entrypoint(void)
+{
+#ifdef PRELOADED_BL33_BASE
+	return PRELOADED_BL33_BASE;
+#else
+	return PLAT_SUNXI_NS_IMAGE_OFFSET;
+#endif
+}
+
+void sunxi_configure_mmu_el3(int flags)
+{
+	mmap_add_region(BL31_BASE, BL31_BASE,
+			BL31_LIMIT - BL31_BASE,
+			MT_MEMORY | MT_RW | MT_SECURE);
+	mmap_add_region(BL_CODE_BASE, BL_CODE_BASE,
+			BL_CODE_END - BL_CODE_BASE,
+			MT_CODE | MT_SECURE);
+	mmap_add_region(BL_RO_DATA_BASE, BL_RO_DATA_BASE,
+			BL_RO_DATA_END - BL_RO_DATA_BASE,
+			MT_RO_DATA | MT_SECURE);
+	mmap_add_region(BL_COHERENT_RAM_BASE, BL_COHERENT_RAM_BASE,
+			BL_COHERENT_RAM_END - BL_COHERENT_RAM_BASE,
+			MT_DEVICE | MT_RW | MT_SECURE);
+	mmap_add(sunxi_mmap);
+	init_xlat_tables();
+
+	enable_mmu_el3(0);
+}