boston: Setup memory ranges in FDT provided to Linux

The boston memory map isn't suited to the simple "all memory starting
from 0" approach that the MIPS arch_fixup_fdt() implementation takes.
Instead we need to indicate the first 256MiB of DDR from 0 and the rest
from 0x90000000. Implement ft_board_setup to do that.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Signed-off-by: NDaniel Schwierzeck <daniel.schwierzeck@gmail.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>

arch/mips/Kconfig

@@ -97,6 +97,7 @@ config TARGET_BOSTON
 	select MIPS_CM
 	select MIPS_L1_CACHE_SHIFT_6
 	select MIPS_L2_CACHE
+	select OF_BOARD_SETUP
 	select SUPPORTS_BIG_ENDIAN
 	select SUPPORTS_LITTLE_ENDIAN
 	select SUPPORTS_CPU_MIPS32_R1

board/imgtec/boston/Makefile

@@ -6,4 +6,5 @@
 
 obj-y += checkboard.o
 obj-y += ddr.o
+obj-y += dt.o
 obj-y += lowlevel_init.o

board/imgtec/boston/dt.c

+/*
+ * Copyright (C) 2016 Imagination Technologies
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#include <common.h>
+#include <fdt_support.h>
+
+int ft_board_setup(void *blob, bd_t *bd)
+{
+	DECLARE_GLOBAL_DATA_PTR;
+	u64 mem_start[2], mem_size[2];
+	int mem_regions;
+
+	mem_start[0] = 0;
+	mem_size[0] = min_t(u64, 256llu << 20, gd->ram_size);
+	mem_regions = 1;
+
+	if (gd->ram_size > mem_size[0]) {
+		mem_start[1] = 0x80000000 + mem_size[0];
+		mem_size[1] = gd->ram_size - mem_size[0];
+		mem_regions++;
+	}
+
+	return fdt_fixup_memory_banks(blob, mem_start, mem_size, mem_regions);
+}