[RK3399][Android7.1] Uboot所用交叉编译工具链

Uboot: v2017.02

Board: Firefly-RK3399

Uboot的交叉编译工具链通过宏CROSS_COMPILE来定义，在Makefile中。

ifeq ($(ARCHV),aarch64)

ifneq ($(wildcard ../toolchain/aarch64-linux-android-4.9),)
CROSS_COMPILE   ?= $(shell pwd)/../toolchain/aarch64-linux-android-4.9/bin/aarch64-linux-android-
endif
ifneq ($(wildcard ../prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/bin),)
CROSS_COMPILE   ?= $(shell pwd)/../prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/bin/aarch64-linux-android-
endif

else

ifneq ($(wildcard ../toolchain/arm-eabi-4.8),)
CROSS_COMPILE   ?= $(shell pwd)/../toolchain/arm-eabi-4.8/bin/arm-eabi-
endif
ifneq ($(wildcard ../toolchain/arm-eabi-4.7),)
CROSS_COMPILE   ?= $(shell pwd)/../toolchain/arm-eabi-4.7/bin/arm-eabi-
endif
ifneq ($(wildcard ../toolchain/arm-eabi-4.6),)
CROSS_COMPILE   ?= $(shell pwd)/../toolchain/arm-eabi-4.6/bin/arm-eabi-
endif
ifneq ($(wildcard ../prebuilts/gcc/linux-x86/arm/arm-eabi-4.8/bin),)
CROSS_COMPILE   ?= $(shell pwd)/../prebuilts/gcc/linux-x86/arm/arm-eabi-4.8/bin/arm-eabi-
endif
ifneq ($(wildcard ../prebuilts/gcc/linux-x86/arm/arm-eabi-4.7/bin),)
CROSS_COMPILE   ?= $(shell pwd)/../prebuilts/gcc/linux-x86/arm/arm-eabi-4.7/bin/arm-eabi-
endif
ifneq ($(wildcard ../prebuilts/gcc/linux-x86/arm/arm-eabi-4.6/bin),)
CROSS_COMPILE   ?= $(shell pwd)/../prebuilts/gcc/linux-x86/arm/arm-eabi-4.6/bin/arm-eabi-
endif

endif # ARCHV=aarch64

rk3399平台是64位， 所以只能用4.9版本。如果是32位，那么依次是4.8, 4.7, 4.6….

代码中已带有4.9版本，所以无需另外下载。