在uboot传递给kernel 内存参数减半：
diff --git a/arch/arm/mach-rockchip/param.c b/arch/arm/mach-rockchip/param.c
old mode 100644
new mode 100755
index 21a4570..4f3fd06
--- a/arch/arm/mach-rockchip/param.c
+++ b/arch/arm/mach-rockchip/param.c
@@ -294,7 +294,7 @@ struct memblock *param_parse_ddr_mem(int *out_count)
/* 0~4GB */
if (base < SZ_4GB) {
mem[n].base = base;
- mem[n].size = ddr_mem_get_usable_size(base, size);
+ mem[n].size = ddr_mem_get_usable_size(base, size)/2;
if (base + size > SZ_4GB) {
n++;
mem[n].base_u64 = SZ_4GB;