ifeq ($(INTERNAL_USERIMAGES_USE_EXT),true) ## generate an ext image # $(1): output file define build-systemimage-target @echo "Target system fs image: $(1)" $(call build-userimage-ext-target,$(TARGET_OUT),$(1),system,$(INTERNAL_USERIMAGES_EXT_VARIANT),$(BOARD_SYSTEMIMAGE_PARTITION_SIZE)) endef else # INTERNAL_USERIMAGES_USE_EXT != true ## generate a yaffs2 image # $(1): output file define build-systemimage-target @echo "Target system fs image: $(1)" @mkdir -p $(dir $(1)) $(hide) $(MKYAFFS2) -f $(mkyaffs2_extra_flags) $(TARGET_OUT) $(1) endef endif # INTERNAL_USERIMAGES_USE_EXT
2. 查看了一下 INTERNAL_USERIMAGES_USE_EXT 在Makefile 中的定义:
INTERNAL_USERIMAGES_EXT_VARIANT := ifeq ($(TARGET_USERIMAGES_USE_EXT2), true) INTERNAL_USERIMAGES_USE_EXT := true; INTERNAL_USERIMAGES_EXT_VARIANT :=ext2 else ifeq ($(TARGET_USERIMAGES_USE_EXT3), true) INTERNAL_USERIMAGES_USE_EXT := true INTERNAL_USERIMAGES_EXT_VARIANT :=ext3 else ifeq ($(TARGET_USERIMAGES_USE_EXT4, true) INTERNAL_USERIMAGES_USE_EXT := true INTERNAL_USERIMAGES_EXT_VARIANT :=ext4 endif endif endif