u-boot关于SPL有三个配置项，CONFIG_SUPPORT_SPL、CONFIG_SPL和CONFIG_SPL_BUILD，其中CONFIG_SUPPORT_SPL和CONFIG_SPL在Kconfig中定义，如下：
config SUPPORT_SPL
bool
config SUPPORT_TPL
bool
config SPL
bool
depends on SUPPORT_SPL
prompt "Enable SPL"
help
If you want to build SPL as well as the normal image, say Y.CONFIG_SUPPORT_SPL表示是否支持SPL功能，一般是在具体arch的Kconfig的版型菜单中，根据需要select
u-boot中CONFIG_SUPPORT_SPL、CONFIG_SPL和CONFIG_SPL_BUILD的作用
原文：https://www.cnblogs.com/liujunhuasd/p/13171287.html