of: create default early_init_dt_add_memory_arch

Create a weak version of early_init_dt_add_memory_arch which uses
memblock. This will unify all architectures except ones with custom
memory bank structs.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Jonas Bonn <jonas@southpole.se>
Acked-by: Grant Likely <grant.likely@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: microblaze-uclinux@itee.uq.edu.au
Cc: linux@lists.openrisc.net
Cc: devicetree@vger.kernel.org
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index bfbfda5..5bc55b6 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -775,6 +775,25 @@
 }
 
 #ifdef CONFIG_HAVE_MEMBLOCK
+void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
+{
+	const u64 phys_offset = __pa(PAGE_OFFSET);
+	base &= PAGE_MASK;
+	size &= PAGE_MASK;
+	if (base + size < phys_offset) {
+		pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
+			   base, base + size);
+		return;
+	}
+	if (base < phys_offset) {
+		pr_warning("Ignoring memory range 0x%llx - 0x%llx\n",
+			   base, phys_offset);
+		size -= phys_offset - base;
+		base = phys_offset;
+	}
+	memblock_add(base, size);
+}
+
 /*
  * called from unflatten_device_tree() to bootstrap devicetree itself
  * Architectures can override this definition if memblock isn't used