Makefile.buildroot

BR_EXT_PATH=$(PWD)
# buildroot output path, pleas find details in https://buildroot.org/downloads/manual/manual.html#_building_out_of_tree
BR_OUTPUT := $(BR_EXT_PATH)/output
COMMON_DEFS := -C buildroot O=$(BR_OUTPUT) BR2_EXTERNAL=$(BR_EXT_PATH)
DEFCONFIG := $(shell echo configs/*_defconfig)
KERNEL_CONFIG := $(shell echo configs/*_kernel.config)
BUSYBOX_CONFIG := $(shell echo configs/*_busybox.config)
BR_CONFIGS := $(DEFCONFIG) $(KERNEL_CONFIG) $(BUSYBOX_CONFIG)

ROOTFS_TAR := $(BR_OUTPUT)/images/rootfs.tar
DISK_IMG := images/disk.img

.PHONY: all
all: $(DISK_IMG) 

$(DISK_IMG): $(ROOTFS_TAR)
	@mkdir -p $(@D)
	sh $(SH_VERBOSE) scripts/genimage.sh $@ $(BR_OUTPUT)

$(ROOTFS_TAR): .config
	$(MAKE) $(COMMON_DEFS)

.PHONY: clean
clean:
	$(MAKE) $(COMMON_DEFS) $@

#############################################################################
# buildroot targets wrapper
#############################################################################

.PHONY: menuconfig
menuconfig: 
	$(MAKE) $(COMMON_DEFS) nconfig BR2_CONFIG=$(abspath $(DEFCONFIG)) 
	
.PHONY: kernelconfig
kernelconfig: .config
	$(MAKE) $(COMMON_DEFS) linux-menuconfig 
	cp build/linux-[0-9].*/.config $(KERNEL_CONFIG)

.PHONY: busyboxconfig
busyboxconfig: .config
	$(MAKE) $(COMMON_DEFS) busybox-menuconfig 
	cp build/busybox-[0-9].*/.config $(BUSYBOX_CONFIG)

.config: $(BR_CONFIGS)
	$(MAKE) $(COMMON_DEFS) $(<F)