uboot编译流程分析 ===================== u-boot官方在线文档 https://u-boot.readthedocs.io/en/latest/index.html 在分析uboot编译过程之前，必须了解Makefile语法。由于u-boot的Makefile中存在相互调用，这里介绍以下make -f和make -c的区别 - -c选项：Makefile中的-c是递归调用子目录的Makefile，-c选项后跟目录，表示到子目录下执行子目录的makefile，顶层Makefile的export的变量还有make默认的变量是可以传递给子目录中的Makefile的 - -f选项：顶层Makefile使用make -f调用子目录中的文件（文件名可以随便，不必一定是Makefile)作为Makefile，顶层export的变量可以传递给底层 .. note:: 在顶层Makefile中使用make -f调用子目录中的文件工作目录仍是顶层目录，即CURDIR变量仍是顶层目录 Makefile的核心是依赖和命令，对于每个目标，首先会检查依赖如果依赖存在则执行命令更新目标，如果依赖不存在，则会以依赖为目标先生成依赖，最后执行命令生成目标 make xxx_defconfig配置分析 -------------------------- xxx_defconfig依赖检查更新 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 在编译uboot时首先执行make xxx_defconfig生成.config文件。uboot根目录中Makefile中有唯一的规则目标 :: config: scripts_basic outputmakefile FORCE $(Q)$(MAKE) $(build)=scripts/kconfig $@ %config: scripts_basic outputmakefile FORCE $(Q)$(MAKE) $(build)=scripts/kconfig $@ build 在 scripts/Kbuild.include 中定义 :: build := -f $(srctree)/scripts/Makefile.build obj 所以最后执行的命令就是 :: make -f scripts/Makefile.build obj=scripts/kconfig xxx_defconfig **scripts_basic依赖** 目标xxx_defconfig的生成依赖于scripts_basic，outputmakefile和FORCE,只有scripts_basic需要执行命令 :: # Basic helpers built in scripts/ PHONY += scripts_basic scripts_basic: $(Q)$(MAKE) $(build)=scripts/basic $(Q)rm -f .tmp_quiet_recordmcount #展开后，规则如下 make -f ./scripts/Makefile.build obj=scripts/basic #make命令会转到文件scripts/Makefile.build去执行 事实上大量实际目标的编译都是调用scripts/Makefile.build完成的，文件scripts/Makefile.build的开头会根据传入的obj=scripts/basic参数设置src=sripts/basic :: # Modified for U-Boot prefix := tpl src := $(patsubst $(prefix)/%,%,$(obj)) ifeq ($(obj),$(src)) prefix := spl src := $(patsubst $(prefix)/%,%,$(obj)) ifeq ($(obj),$(src)) prefix := . endif endif kbuild-dir根据src变量(等于obj变量)是绝对路径还是相对路径来确定当前编译的目录，若为绝对路径则该目录即src变量的值，若为相对路径则该变量就是src相对于源码根目录的目录。kbuild-file即 在该目录下查找kbuild文件，若能找到则使用kbuild作为该目录的编译文件，若找不到则使用该目录下的Makefile作为该目录的编译文件，然后将该文件包含进来 :: # The filename Kbuild has precedence over Makefile kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile) include $(kbuild-file) 这里展开替换后相当于 :: include ./scripts/basic/Makefile 文件scripts/basic/Makefile中定义了编译在主机上执行的工具fixdep :: # fixdep: Used to generate dependency information during build process hostprogs-y := fixdep always := $(hostprogs-y) # fixdep is needed to compile other host programs $(addprefix $(obj)/,$(filter-out fixdep,$(always))): $(obj)/fixdep fixdep用于更新每一个生成目标的依赖文件*.cmd。上面定义的这个$(always)在scripts/Makefile.build里会被添加到targets中 :: targets += $(extra-y) $(MAKECMDGOALS) $(always) 简而言之，scripts_basic的规则是 :: scripts_basic: make -f ./scripts/Makefile.build obj=scripts/basic 最终的结果就是编译scripts/basic/fixdep.c 生成主机上的可执行文件fixdep **outputmakefile依赖** :: PHONY += outputmakefile # outputmakefile generates a Makefile in the output directory, if using a # separate output directory. This allows convenient use of make in the # output directory. outputmakefile: ifneq ($(KBUILD_SRC),) $(Q)ln -fsn $(srctree) source $(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile \ $(srctree) $(objtree) $(VERSION) $(PATCHLEVEL) endif 如果此时执行 make xxx_defconfig O=out,那么所有生成的目标都将放到out目录，outputmakefile会导出一个makefile到out目录进行编译 **FORCE依赖** :: PHONY += FORCE FORCE: FORCE被定义为一个空目标，如果一个目标添加FORCE依赖每次编译都会西安去执行FORCE(实际上什么都不做),然后运行命令更新目标，这样就能确保目标每次都被更新 xxx_defconfig目标命令执行 ^^^^^^^^^^^^^^^^^^^^^^^^^ 完成对xxx_defconfig的依赖更新后，接下来就是执行对顶层目标的命令完成对xxx_defconfig的更新,也就是执行以下命令 :: xxx_defconfig: scripts_basic outputmakefile FORCE make -f ./scripts/Makefile.build obj=scripts/kconfig xxx_defconfig 这个命令会转到srcipts/Makefile.kbuild去执行,文件scripts/Makefile.kbuild的开头会根据传入的obj=scripts/kconfig参数设置src=scripts/kconfig, 然后搜寻$(srctree)/$(src)子目录下的makefile， 由于src=scripts/kconfig参数不用于第一次调用的参数(src=scripts/basic)此处包含的makefile也不用于第一次的makefile了 :: # The filename Kbuild has precedence over Makefile kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile) include $(kbuild-file) 这里展开后相当于 :: include ./scripts/kconfig/Makefile 文件scripts/kconfig/Makefile中定义了所有匹配%config的目标 :: PHONY += xconfig gconfig menuconfig config syncconfig update-po-config \ %_defconfig: $(obj)/conf $(Q)$< $(silent) --defconfig=arch/$(SRCARCH)/configs/$@ $(Kconfig) 展开为 :: xxx_defconfig: scripts/kconfig/conf scripts/kconfig/conf --defconfig=arch/arm/configs/xxx_defconfig Kconfig 此处xxx_defconfig依赖scripts/kconfig/conf,接下来检查并生成依赖 :: hostprogs-y := conf nconf mconf kxgettext qconf gconf conf-objs := conf.o zconf.tab.o hostprogs-y指出conf被定义为主机上执行的程序，其依赖于另外两个文件 conf.o zconf.tab.o。通过编译conf.c和zconf.tab.c生成conf-objs并链接为scripts/kconfig/conf。生成 依赖后就是执行目标的命令了 conf工具从根目录下开始树状读取默认的kconf文件,分析其配置并保存在内存中，分析完默认的kconfig后再读取指定的文件(arch/arm/configs/xxx_defconfig)更新得到最后的符号表，并输出到.config文件中， 至此完成了make xxx_defconfig执行配置涉及到的所有依赖和命令的分析 make defconfig配置流程简图 .. image:: res/make_defconfig.png make执行流程分析 ----------------- 目标_all和all对$(ALL-y)的依赖 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 从顶层的Makefile开始查找，找到第一个目标为_all :: PHONY := _all _all: PHONY += all ifeq ($(KBUILD_EXTMOD),) ##当我们定义了KBUILD_EXTMOD编译一个外部模块时，_all依赖Modules否则依赖all _all: all else _all: modules endif 在Makefile中.PHONY后面的target表示也是一个伪造的target，而不是真实存在的文件target，注意makefile的target默认是文件 接着往下分析,all自身依赖于$(ALL-y) :: all: $(ALL-y) cfg ifeq ($(CONFIG_DM_I2C_COMPAT)$(CONFIG_SANDBOX),y) @echo "===================== WARNING ======================" @echo "This board uses CONFIG_DM_I2C_COMPAT. Please remove" @echo "(possibly in a subsequent patch in your series)" @echo "before sending patches to the mailing list." @echo "====================================================" endif @# Check that this build does not use CONFIG options that we do not @# know about unless they are in Kconfig. All the existing CONFIG @# options are whitelisted, so new ones should not be added. $(call cmd,cfgcheck,u-boot.cfg) **目标$(ALL-y)** :: # Always append ALL so that arch config.mk's can add custom ones ALL-y += u-boot.srec u-boot.bin u-boot.sym System.map binary_size_check ALL-$(CONFIG_ONENAND_U_BOOT) += u-boot-onenand.bin ifeq ($(CONFIG_SPL_FSL_PBL),y) ALL-$(CONFIG_RAMBOOT_PBL) += u-boot-with-spl-pbl.bin else ifneq ($(CONFIG_SECURE_BOOT), y) # For Secure Boot The Image needs to be signed and Header must also # be included. So The image has to be built explicitly ALL-$(CONFIG_RAMBOOT_PBL) += u-boot.pbl endif endif ALL-$(CONFIG_SPL) += spl/u-boot-spl.bin ifeq ($(CONFIG_MX6)$(CONFIG_SECURE_BOOT), yy) ALL-$(CONFIG_SPL_FRAMEWORK) += u-boot-ivt.img else ifeq ($(CONFIG_MX7)$(CONFIG_SECURE_BOOT), yy) ALL-$(CONFIG_SPL_FRAMEWORK) += u-boot-ivt.img else ALL-$(CONFIG_SPL_FRAMEWORK) += u-boot.img endif endif ALL-$(CONFIG_TPL) += tpl/u-boot-tpl.bin ALL-$(CONFIG_OF_SEPARATE) += u-boot.dtb ifeq ($(CONFIG_SPL_FRAMEWORK),y) ALL-$(CONFIG_OF_SEPARATE) += u-boot-dtb.img endif ALL-$(CONFIG_OF_HOSTFILE) += u-boot.dtb ifneq ($(CONFIG_SPL_TARGET),) ALL-$(CONFIG_SPL) += $(CONFIG_SPL_TARGET:"%"=%) endif ALL-$(CONFIG_REMAKE_ELF) += u-boot.elf ALL-$(CONFIG_EFI_APP) += u-boot-app.efi ALL-$(CONFIG_EFI_STUB) += u-boot-payload.efi ifneq ($(BUILD_ROM)$(CONFIG_BUILD_ROM),) ALL-$(CONFIG_X86_RESET_VECTOR) += u-boot.rom endif # Build a combined spl + u-boot image for sunxi ifeq ($(CONFIG_ARCH_SUNXI)$(CONFIG_SPL),yy) ALL-y += u-boot-sunxi-with-spl.bin endif # enable combined SPL/u-boot/dtb rules for tegra ifeq ($(CONFIG_TEGRA)$(CONFIG_SPL),yy) ALL-y += u-boot-tegra.bin u-boot-nodtb-tegra.bin ALL-$(CONFIG_OF_SEPARATE) += u-boot-dtb-tegra.bin endif # Add optional build target if defined in board/cpu/soc headers ifneq ($(CONFIG_BUILD_TARGET),) ALL-y += $(CONFIG_BUILD_TARGET:"%"=%) endif ifneq ($(CONFIG_SYS_INIT_SP_BSS_OFFSET),) ALL-y += init_sp_bss_offset_check endif 以上的$(ALL-y)目标中看起来很复杂，但除了第一行的通用目标外，其他目标都是在特殊条件下才会生成，这里暂时不提 **$(ALL-y)依赖u-boot.srec** :: u-boot.hex u-boot.srec: u-boot FORCE $(call if_changed,objcopy) **$(ALL-y)依赖u-boot.bin** :: ifeq ($(CONFIG_MULTI_DTB_FIT),y) fit-dtb.blob: dts/dt.dtb FORCE $(call if_changed,mkimage) MKIMAGEFLAGS_fit-dtb.blob = -f auto -A $(ARCH) -T firmware -C none -O u-boot \ -a 0 -e 0 -E \ $(patsubst %,-b arch/$(ARCH)/dts/%.dtb,$(subst ",,$(CONFIG_OF_LIST))) -d /dev/null u-boot-fit-dtb.bin: u-boot-nodtb.bin fit-dtb.blob $(call if_changed,cat) u-boot.bin: u-boot-fit-dtb.bin FORCE $(call if_changed,copy) else ifeq ($(CONFIG_OF_SEPARATE),y) u-boot-dtb.bin: u-boot-nodtb.bin dts/dt.dtb FORCE $(call if_changed,cat) u-boot.bin: u-boot-dtb.bin FORCE $(call if_changed,copy) else u-boot.bin: u-boot-nodtb.bin FORCE $(call if_changed,copy) endif 如果打开了device tree的支持，则有依赖关系 :: u-boot.bin---->u-boot-dtb.bin----->u-boot-nodtb.bin + dts/dt.dtb 如果没有定义CONFIG_OF_SEPARATE则依赖关系如下 :: u-boot.bin ----> u-boot-nodtb.bin u-boot-nodtb.bin的依赖关系以及执行命令如下 :: u-boot-nodtb.bin: u-boot FORCE $(call if_changed,objcopy) $(call DO_STATIC_RELA,$<,$@,$(CONFIG_SYS_TEXT_BASE)) $(BOARD_SIZE_CHECK) 命令中if_changed函数定义在scripts/Kbuild.include文件中,顶层Makefile中通过以下命令包含 :: scripts/Kbuild.include: ; include scripts/Kbuild.include if_changed函数定义如下 :: if_changed = $(if $(strip $(any-prereq) $(arg-check)), \ @set -e; \ $(echo-cmd) $(cmd_$(1)); \ printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd) 该命令外层是一个if函数，然后又内嵌了一个strip函数 :: OBJCOPY = $(CROSS_COMPILE)objcopy # Normally we fill empty space with 0xff quiet_cmd_objcopy = OBJCOPY $@ cmd_objcopy = $(OBJCOPY) --gap-fill=0xff $(OBJCOPYFLAGS) \ $(OBJCOPYFLAGS_$(@F)) $< $@ 所以$(call if_changed,objcopy)展开后： :: echo objcopy $@; objcopy $< $@ 就是说利用objcopy命令将u-boot转换为u-boot-nodtb.bin **$(ALL-y)依赖u-boot.sym** :: u-boot.sym: u-boot FORCE $(call if_changed,sym) **$(ALL-y)依赖System.map** :: System.map: u-boot @$(call SYSTEM_MAP,$<) > $@ **$(ALL-y)依赖u-boot.cfg** :: u-boot.cfg spl/u-boot.cfg tpl/u-boot.cfg: include/config.h FORCE $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.autoconf $(@) include/config.h在make xxx_defconfig时创建,include/config.h文件中会包含板级配置文件如#include **$(ALL-y)依赖binary_size_check** :: binary_size_check: u-boot-nodtb.bin FORCE @file_size=$(shell wc -c u-boot-nodtb.bin | awk '{print $$1}') ; \ map_size=$(shell cat u-boot.map | \ awk '/_image_copy_start/ {start = $$1} /_image_binary_end/ {end = $$1} END {if (start != "" && end != "") print "ibase=16; " toupper(end) " - " toupper(start)}' \ | sed 's/0X//g' \ | bc); \ if [ "" != "$$map_size" ]; then \ if test $$map_size -ne $$file_size; then \ echo "u-boot.map shows a binary size of $$map_size" >&2 ; \ echo " but u-boot-nodtb.bin shows $$file_size" >&2 ; \ exit 1; \ fi \ fi 以上通用目标$(ALL-y)的依赖有一个共同点，除了u-boot.cfg依赖于include/config.h外其余目标都依赖于u-boot, 以下图中表示了_all依赖简图 .. image:: res/_all_dep.png u-boot目标编译 ^^^^^^^^^^^^^^^ u-boot目标依赖及执行命令如下 :: u-boot: $(u-boot-init) $(u-boot-main) u-boot.lds FORCE +$(call if_changed,u-boot__) ifeq ($(CONFIG_KALLSYMS),y) $(call cmd,smap) $(call cmd,u-boot__) common/system_map.o endif 其中u-boot-init和u-boot-main被定义为 :: u-boot-init := $(head-y) u-boot-main := $(libs-y) **依赖项head-y libs-y** head-y 在arch/arm/Makefile中定义 :: head-y := arch/arm/cpu/$(CPU)/start.o 所以head-y指的是start.S 在顶层目录Makefile中搜索libs-y可以发现其包含许多目录， :: libs-y += lib/ libs-$(HAVE_VENDOR_COMMON_LIB) += board/$(VENDOR)/common/ libs-$(CONFIG_OF_EMBED) += dts/ libs-y += fs/ libs-y += net/ libs-y += disk/ libs-y += drivers/ libs-y += drivers/dma/ libs-y += drivers/gpio/ libs-y += drivers/i2c/ libs-y += drivers/net/ libs-y += drivers/net/phy/ libs-y += drivers/pci/ libs-y += drivers/power/ \ drivers/power/domain/ \ drivers/power/fuel_gauge/ \ drivers/power/mfd/ \ drivers/power/pmic/ \ drivers/power/battery/ \ drivers/power/regulator/ libs-y += drivers/spi/ libs-$(CONFIG_FMAN_ENET) += drivers/net/fm/ libs-$(CONFIG_SYS_FSL_DDR) += drivers/ddr/fsl/ libs-$(CONFIG_SYS_FSL_MMDC) += drivers/ddr/fsl/ libs-$(CONFIG_ALTERA_SDRAM) += drivers/ddr/altera/ libs-y += drivers/serial/ libs-y += drivers/usb/dwc3/ libs-y += drivers/usb/common/ libs-y += drivers/usb/emul/ libs-y += drivers/usb/eth/ libs-y += drivers/usb/gadget/ libs-y += drivers/usb/gadget/udc/ libs-y += drivers/usb/host/ libs-y += drivers/usb/musb/ libs-y += drivers/usb/musb-new/ libs-y += drivers/usb/phy/ libs-y += drivers/usb/ulpi/ libs-y += cmd/ libs-y += common/ libs-y += env/ libs-$(CONFIG_API) += api/ libs-$(CONFIG_HAS_POST) += post/ libs-y += test/ libs-y += test/dm/ libs-$(CONFIG_UT_ENV) += test/env/ libs-$(CONFIG_UT_OVERLAY) += test/overlay/ 另外libs-y还有如下规则定义 :: libs-y += $(if $(BOARDDIR),board/$(BOARDDIR)/) libs-y := $(sort $(libs-y)) libs-y := $(patsubst %/, %/built-in.o, $(libs-y)) 这条规则使得libs-y中的每个条目的最后一个斜杠替换成/built-in.o，可见libs-y被定义为各层驱动目录下built-in.o的集合，而这些built-in.o则由kbuild makefile将obj-y所 包含的各个文件编译而成，具体可以研究 ``scripts/Kbuild.include`` 和 ``scripts/Makefile.build`` :: ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),) builtin-target := $(obj)/built-in.o endif $(builtin-target): $(obj-y) FORCE $(call if_changed,link_o_target) u-boot文件目标依赖： .. image:: res/u-boot_dep.png **依赖项u-boot.lds** :: u-boot.lds: $(LDSCRIPT) prepare FORCE $(call if_changed_dep,cpp_lds) ifndef LDSCRIPT #LDSCRIPT := $(srctree)/board/$(BOARDDIR)/u-boot.lds.debug ifdef CONFIG_SYS_LDSCRIPT # need to strip off double quotes LDSCRIPT := $(srctree)/$(CONFIG_SYS_LDSCRIPT:"%"=%) endif endif # If there is no specified link script, we look in a number of places for it ifndef LDSCRIPT ifeq ($(wildcard $(LDSCRIPT)),) LDSCRIPT := $(srctree)/board/$(BOARDDIR)/u-boot.lds endif ifeq ($(wildcard $(LDSCRIPT)),) LDSCRIPT := $(srctree)/$(CPUDIR)/u-boot.lds endif ifeq ($(wildcard $(LDSCRIPT)),) LDSCRIPT := $(srctree)/arch/$(ARCH)/cpu/u-boot.lds endif endif 如果没有定义LDSCRIPT和CONFIG_SYS_LDSCRIPT则默认使用u-boot自带的lds文件，包括board/$(BOARDDIR)和$(CPUDIR)目录下定制的针对board或cpu的lds文件，如果没有定制的lds文件则采用 arch/arm/cpu目录下默认的lds链接文件u-boot.lds prepare编译 """""""""""" 实际上prepare是一些列prepare伪目标和动作的组合，完成编译前的准备工作 :: # Listed in dependency order PHONY += prepare archprepare prepare0 prepare1 prepare2 prepare3 prepare3: include/config/uboot.release ifneq ($(KBUILD_SRC),) @$(kecho) ' Using $(srctree) as source for U-Boot' $(Q)if [ -f $(srctree)/.config -o -d $(srctree)/include/config ]; then \ echo >&2 " $(srctree) is not clean, please run 'make mrproper'"; \ echo >&2 " in the '$(srctree)' directory.";\ /bin/false; \ fi; endif # prepare2 creates a makefile if using a separate output directory prepare2: prepare3 outputmakefile prepare1: prepare2 $(version_h) $(timestamp_h) \ include/config/auto.conf archprepare: prepare1 scripts_basic prepare0: archprepare FORCE $(Q)$(MAKE) $(build)=. # All the preparing.. prepare: prepare0 各个prepare目标的依赖关系如下 .. image:: res/prepare_dep.png 在prepare1的依赖列表中，除了include/config/auto.conf之外，还有$(version_h)和$(timestamp_h),他们的依赖关系如下 :: $(version_h): include/config/uboot.release FORCE $(call filechk,version.h) $(timestamp_h): $(srctree)/Makefile FORCE $(call filechk,timestamp.h) 对于位于最后的prepare3的依赖include/config/uboot.release它还有下级依赖 :: include/config/uboot.release: include/config/auto.conf FORCE $(call filechk,uboot.release) 对于include/config/auto.conf，Makefile还有一个匹配规则 :: include/config/%.conf: $(KCONFIG_CONFIG) include/config/auto.conf.cmd $(Q)$(MAKE) -f $(srctree)/Makefile syncconfig @# If the following part fails, include/config/auto.conf should be @# deleted so "make silentoldconfig" will be re-run on the next build. $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.autoconf || \ { rm -f include/config/auto.conf; false; } @# include/config.h has been updated after "make silentoldconfig". @# We need to touch include/config/auto.conf so it gets newer @# than include/config.h. @# Otherwise, 'make silentoldconfig' would be invoked twice. $(Q)touch include/config/auto.conf include/config/auto.conf依赖于$(KCONFIG_CONFIG)和include/config/auto.conf.cmd，其中： - $(KCONFIG_CONFIG)实际上就是.config文件 - include/config/auto.conf.cmd是由fixdep在编译时生成的依赖文件 **make编译流程图** .. image:: res/make.png 完成目标依赖分析后，剩下的就是基于完整的目标依赖关系图，从最底层的依赖开始，逐行运行命令生成目标，直到生成顶层目标 **补充 ---- config.h文件生成** 此处进行函数定义 :: ##scripts/Kbuild.include文件中 define filchk $(Q)set -e; \ $(kecho) ' CHK $@'; \ mkdir -p $(dir $@); \ $(filechk_$(1)) < $< > $@.tmp; \ if [ -r $@ ] && cmp -s $@ $@.tmp; then \ rm -f $@.tmp; \ else \ $(kecho) ' UPD $@'; \ mv -f $@.tmp $@; \ fi endef 具体的文件生成则在以下文件中实现 :: # scripts/Makefile.autoconf文件中 # Prior to Kconfig, it was generated by mkconfig. Now it is created here. define filechk_config_h (echo "/* Automatically generated - do not edit */"; \ for i in $$(echo $(CONFIG_SYS_EXTRA_OPTIONS) | sed 's/,/ /g'); do \ echo \#define CONFIG_$$i \ | sed '/=/ {s/=/ /;q; } ; { s/$$/ 1/; }'; \ done; \ echo \#define CONFIG_BOARDDIR board/$(if $(VENDOR),$(VENDOR)/)$(BOARD);\ echo \#include \; \ echo \#include \; \ echo \#include \; \ echo \#include \; \ echo \#include \; \ echo \#include \;) endef include/config.h: scripts/Makefile.autoconf create_symlink FORCE $(call filechk,config_h) u-boot.cfg: include/config.h FORCE $(call cmd,u_boot_cfg) spl/u-boot.cfg: include/config.h FORCE $(Q)mkdir -p $(dir $@) $(call cmd,u_boot_cfg,-DCONFIG_SPL_BUILD) tpl/u-boot.cfg: include/config.h FORCE $(Q)mkdir -p $(dir $@) $(call cmd,u_boot_cfg,-DCONFIG_SPL_BUILD -DCONFIG_TPL_BUILD) include/autoconf.mk: u-boot.cfg $(call cmd,autoconf)