Optimizing makefiles

Makefile

@@ -7,10 +7,13 @@ curPath:=$(abspath .)
 srcPath:=$(curPath)/src
 imgPath:=$(curPath)/sdcard
 
-all: platform freertos
+all: dir platform freertos
+
+dir:
+	@mkdir -p $(imgPath)
 
 include platform.mk
 include freertos.mk
 include linux.mk
 
-.PHONY: all 
+.PHONY: dir all

freertos.mk

@@ -2,6 +2,8 @@
 freertos_src:=$(srcPath)/freertos
 freertos_dest_image:=$(imgPath)/freertos.bin
 
-freertos $(freertos_dest_image): $(freertos_src)
+$(freertos_dest_image): $(freertos_src)
 	$(MAKE) -C $(freertos_src) PLATFORM=$(PLATFORM)
-	cp $(freertos_src)/build/$(PLATFORM)/freertos.bin $(freertos_dest_image)
+	cp $(freertos_src)/build/$(PLATFORM)/freertos.bin $(freertos_dest_image)
+
+freertos: $(freertos_dest_image)

platform.mk

@@ -5,7 +5,7 @@ firmware_images:=$(curPath)/firmware-rpi
 
 atf_src:=$(srcPath)/arm-trusted-firmware
 atf_dest_image:=$(imgPath)/bl31.bin
-atf_plat:=PLATFORM
+atf_plat:=$(PLATFORM)
 
 uboot_src:=$(srcPath)/u-boot
 uboot_defconfig:=rpi_4_defconfig
@@ -24,14 +24,9 @@ u-boot $(uboot_dest_image): $(uboot_src)
 $(firmware_images):
 	git clone --depth 1 --branch $(firmware_version) $(firmware_repo) $(firmware_images)
 
-sdcardDir:
-	@mkdir -p $(imgPath)
-
 #instuctions:=$(bao_demos)/platforms/$(PLATFORM)/README.md
 
-platform: sdcardDir $(uboot_dest_image) $(atf_dest_image) $(firmware_images)
+platform: $(uboot_dest_image) $(atf_dest_image) $(firmware_images)
 #	$(call print-instructions, $(instuctions), 1, false)
 #	$(call print-instructions, $(instuctions), 2, false)
-#	$(call print-instructions, $(instuctions), 3, true)
-
-.PHONY: sdcardDir
+#	$(call print-instructions, $(instuctions), 3, true)