Makefile

obj-y := initramfs_data.o

hostprogs-y  := gen_init_cpio

clean-files := initramfs_data.cpio.gz initramfs_list

# initramfs_data.o contains the initramfs_data.cpio.gz image.
# The image is included using .incbin, a dependency which is not
# tracked automatically.
$(obj)/initramfs_data.o: $(obj)/initramfs_data.cpio.gz FORCE

ifdef CONFIG_INITRAMFS_ROOT_UID
gen_initramfs_args += -u $(CONFIG_INITRAMFS_ROOT_UID)
endif

ifdef CONFIG_INITRAMFS_ROOT_GID
gen_initramfs_args += -g $(CONFIG_INITRAMFS_ROOT_GID)
endif

# The $(shell echo $(CONFIG_INITRAMFS_SOURCE)) is to remove the
# gratuitous begin and end quotes from the Kconfig string type.
# Internal, escaped quotes in the Kconfig string will loose the
# escape and become active quotes.
quotefixed_initramfs_source := $(shell echo $(CONFIG_INITRAMFS_SOURCE))

filechk_initramfs_list = $(CONFIG_SHELL) \
 $(srctree)/scripts/gen_initramfs_list.sh $(gen_initramfs_args) $(quotefixed_initramfs_source)

$(obj)/initramfs_list: $(obj)/Makefile FORCE
	$(call filechk,initramfs_list)

quiet_cmd_cpio = CPIO    $@
      cmd_cpio = ./$< $(obj)/initramfs_list > $@


# Check if the INITRAMFS_SOURCE is a cpio archive
ifneq (,$(findstring .cpio,$(quotefixed_initramfs_source)))

# INITRAMFS_SOURCE has a cpio archive - verify that it's a single file
ifneq (1,$(words $(quotefixed_initramfs_source)))
$(error Only a single file may be specified in CONFIG_INITRAMFS_SOURCE (="$(quotefixed_initramfs_source)") when a cpio archive is directly specified.)
endif
# Now use the cpio archive directly
initramfs_data_cpio = $(quotefixed_initramfs_source)
targets += $(quotefixed_initramfs_source)

else

# INITRAMFS_SOURCE is not a cpio archive - create one
$(obj)/initramfs_data.cpio: $(obj)/gen_init_cpio \
                            $(initramfs-y) $(obj)/initramfs_list FORCE
	$(call if_changed,cpio)

targets += initramfs_data.cpio
initramfs_data_cpio = $(obj)/initramfs_data.cpio

endif


$(obj)/initramfs_data.cpio.gz: $(initramfs_data_cpio) FORCE
	$(call if_changed,gzip)

targets += initramfs_data.cpio.gz