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编写:编译uboot的过程分析
This commit is contained in:
weidongshan
@@ -26,7 +26,7 @@ make过程
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## 5.2 详细分析
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## 5.2 配置过程详细分析
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参考资料：https://www.cnblogs.com/jianhua1992/archive/2022/11/02/16852774.html
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@@ -361,28 +361,156 @@ endif
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### 5.2.4 编译过程
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## 5.3 编译过程详细分析(IMX6ULL)
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```shell
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book@100ask:~/100ask_imx6ull-sdk/Uboot-2017.03$ grep "head-y" * -nr
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arch/arm/Makefile:85:head-y := arch/arm/cpu/$(CPU)/start.o
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arch/arm/Makefile:89:head-y := $(CONFIG_SPL_START_S_PATH:"%"=%)/start.o
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```
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### 5.3.1 结论
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以IMX6ULL为例，先说结论：
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* 执行make命令时，要编译得到哪些文件由`ALL-y`决定
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* 规则如下
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```shell
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include config.mk # 里面会包含arch/arm/config.mk(含有ALL-y += u-boot-dtb.imx)
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_all : all
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# Always append ALL so that arch config.mk's can add custom ones
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ALL-y += u-boot.srec u-boot.bin u-boot.sym System.map binary_size_check
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ALL-$(CONFIG_OF_SEPARATE) += u-boot.dtb
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all: $(ALL-y)
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```
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* `ALL-y`的值为：
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```shell
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checkarmreloc u-boot-dtb.imx u-boot.srec u-boot.bin u-boot.sym System.map binary_size_check u-boot.dtb
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```
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* u-boot-dtb.imx依赖于u-boot-dtb.bin，u-boot-dtb.bin又依赖于u-boot-nodtb.bin和dts/dt.dtb
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* 各类u-boot文件都依赖于u-boot，先编译得到u-boot，它由`u-boot-init`、`u-boot-main`两部分链接而成
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* u-boot-init为：arch/arm/cpu/armv7/start.o
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* u-boot-main为：lib/built-in.o fs/built-in.o net/built-in.o 等等
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* 如何编译各个built-in.o，以lib/built-in.o为例
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* 执行: ``make -f ./scripts/Makefile.build obj=lib`
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* 会包含lib/Makefile，里面定义了`obj-y`
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* 使用Makefile.build的规则把各个obj-y编译、链接为built-in.o
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* 使用如下的命令链接得到u-boot：
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```shell
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quiet_cmd_u-boot__ ?= LD $@
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cmd_u-boot__ ?= $(LD) $(LDFLAGS) $(LDFLAGS_u-boot) -o $@ \
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-T u-boot.lds $(u-boot-init) \
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--start-group $(u-boot-main) --end-group \
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$(PLATFORM_LIBS) -Map u-boot.map
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```
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* 再编译得到设备树文件: `make -f ./scripts/Makefile.build obj=dts dtbs`
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* 顶层Makefile如下：
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```shell
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dts/dt.dtb: checkdtc u-boot
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$(Q)$(MAKE) $(build)=dts dtbs
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```
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* scripts/Makefile.build中，会包含 dts/Makefile
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```shell
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DTB := arch/$(ARCH)/dts/$(DEVICE_TREE).dtb
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$(DTB): arch-dtbs
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$(obj)/dt.dtb: $(DTB) FORCE
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$(call if_changed,shipped)
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targets += dt.dtb
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$(DTB): arch-dtbs
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$(Q)test -e $@ || ( \
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echo >&2; \
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echo >&2 "Device Tree Source is not correctly specified."; \
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echo >&2 "Please define 'CONFIG_DEFAULT_DEVICE_TREE'"; \
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echo >&2 "or build with 'DEVICE_TREE=<device_tree>' argument"; \
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echo >&2; \
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/bin/false)
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arch-dtbs:
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$(Q)$(MAKE) $(build)=arch/$(ARCH)/dts dtbs
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.SECONDARY: $(obj)/dt.dtb.S
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obj-$(CONFIG_OF_EMBED) := dt.dtb.o
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dtbs: $(obj)/dt.dtb
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@:
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```
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* 最后把u-boot、设备树打包: `make -f ./scripts/Makefile.build obj=arch/arm/imx-common u-boot-dtb.imx`
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```shell
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include config.mk # 里面会包含arch/arm/config.mk(含有ALL-y += u-boot-dtb.imx)
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%.imx: %.bin
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$(Q)$(MAKE) $(build)=arch/arm/imx-common $@
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```
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### 5.3.2 顶层Makefile
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顶层Makefile里指定了第1个文件（head-y）、指定了要编译哪些子目录（libs-y）。
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从顶层Makefile开始分析：
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```shell
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include config.mk
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include arch/$(ARCH)/Makefile # arch/arm/Makefile
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include config.mk # 里面会包含arch/arm/config.mk(含有ALL-y += u-boot-dtb.imx)
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include arch/$(ARCH)/Makefile # arch/arm/Makefile, 里面含有head-y libs-y
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libs-y += lib/
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libs-$(HAVE_VENDOR_COMMON_LIB) += board/$(VENDOR)/common/
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libs-$(CONFIG_OF_EMBED) += dts/
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libs-y += fs/
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libs-y += net/
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libs-y += disk/
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libs-y += drivers/
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libs-y += drivers/dma/
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libs-y += drivers/gpio/
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libs-y += drivers/i2c/
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libs-y += drivers/mmc/
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libs-y += $(if $(BOARDDIR),board/$(BOARDDIR)/)
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libs-y := $(sort $(libs-y))
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u-boot-dirs := $(patsubst %/,%,$(filter %/, $(libs-y))) tools examples
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u-boot-alldirs := $(sort $(u-boot-dirs) $(patsubst %/,%,$(filter %/, $(libs-))))
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libs-y := $(patsubst %/, %/built-in.o, $(libs-y))
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u-boot-init := $(head-y)
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u-boot-main := $(libs-y)
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ALL-y += u-boot.srec u-boot.bin u-boot.sym System.map binary_size_check
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```
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arch/arm/Makefile：
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对于`arch/arm/Makefile`：
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```shell
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head-y := arch/arm/cpu/$(CPU)/start.o
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@@ -394,7 +522,15 @@ libs-y += arch/arm/lib/
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继续回到顶层Makefile：（它会进入每一个libs-y目录，执行里面的Makefile）
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所以，顶层Makefile包含了`arch/arm/Makefile`，确定了head-y为`arch/arm/cpu/armv7/start.o`。
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还定义了libs-y变量，它里面含有多个目录。
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### 5.3.3 编译子目录
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顶层Makefile里定义了libs-y，会进入里面每一目录，使用它的Makefile进行编译：
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```shell
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u-boot-main := $(libs-y)
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@@ -406,29 +542,407 @@ u-boot-dirs := $(patsubst %/,%,$(filter %/, $(libs-y))) tools examples
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$(u-boot-dirs): prepare scripts
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# make -f $(srctree)/scripts/Makefile.build obj=arch/arm/cpu/arm7
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$(Q)$(MAKE) $(build)=$@
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```
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比如：u-boot-main里面含有一个目录"arch/arm/cpu/arm7/"
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比如：u-boot-main里面含有一个目录"arch/arm/cpu/armv7/"，在u-boot-dirs中它末尾的"/"被取消，就变成：arch/arm/cpu/armv7。
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u-boot-dirs就变成：arch/arm/cpu/arm7
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然后使用scripts/Makefile.build进行处理：$(Q)$(MAKE) $(build)=$@ ，展开就是：
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```shell
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make -f /scripts/Makefile.build obj=arch/arm/cpu/armv7/
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```
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进一步分析：scripts/Makefile.build，它是编译u-boot源码的核心
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scripts/Makefile.build是编译u-boot源码的关键：
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```
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src := $(patsubst $(prefix)/%,%,$(obj)) # obj=arch/arm/cpu/arm7/, src=arch/arm/cpu/armv7
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# 第1个目标
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__build:
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# The filename Kbuild has precedence over Makefile
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kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
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kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
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include $(kbuild-file) # 包含 arch/arm/cpu/arm7/Makefile
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ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
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lib-target := $(obj)/lib.a # 如果包含的arch/arm/cpu/armv7/Makefile里定义了lib-y
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endif
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ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),)
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builtin-target := $(obj)/built-in.o # 如果包含的arch/arm/cpu/armv7/Makefile里定义了obj-y
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endif
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__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
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$(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
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$(subdir-ym) $(always)
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@:
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# Built-in and composite module parts
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$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
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$(call cmd,force_checksrc)
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$(call if_changed_rule,cc_o_c)
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ifdef builtin-target
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quiet_cmd_link_o_target = LD $@
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# If the list of objects to link is empty, just create an empty built-in.o
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cmd_link_o_target = $(if $(strip $(obj-y)),\
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$(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^) \
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$(cmd_secanalysis),\
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rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@)
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$(builtin-target): $(obj-y) FORCE
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$(call if_changed,link_o_target)
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targets += $(builtin-target)
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endif # builtin-target
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```
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### 5.3.4 链接得到u-boot
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顶层Makefile里：
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```shell
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libs-y := $(patsubst %/, %/built-in.o, $(libs-y))
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u-boot-init := $(head-y)
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u-boot-main := $(libs-y)
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# Rule to link u-boot
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# May be overridden by arch/$(ARCH)/config.mk
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quiet_cmd_u-boot__ ?= LD $@
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cmd_u-boot__ ?= $(LD) $(LDFLAGS) $(LDFLAGS_u-boot) -o $@ \
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-T u-boot.lds $(u-boot-init) \
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--start-group $(u-boot-main) --end-group \
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$(PLATFORM_LIBS) -Map u-boot.map
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quiet_cmd_smap = GEN common/system_map.o
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cmd_smap = \
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smap=`$(call SYSTEM_MAP,u-boot) | \
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awk '$$2 ~ /[tTwW]/ {printf $$1 $$3 "\\\\000"}'` ; \
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$(CC) $(c_flags) -DSYSTEM_MAP="\"$${smap}\"" \
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-c $(srctree)/common/system_map.c -o common/system_map.o
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u-boot: $(u-boot-init) $(u-boot-main) u-boot.lds FORCE
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$(call if_changed,u-boot__)
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ifeq ($(CONFIG_KALLSYMS),y)
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$(call cmd,smap)
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$(call cmd,u-boot__) common/system_map.o
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endif
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```
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就是把head-y和各个libs-y下的built-in.o链接得到u-boot。
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### 5.3.5 映像文件的依赖
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对于IMX6ULL，要使用的是u-boot-dtb.imx，它含有u-boot和设备树。
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在顶层Makefile里：
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```shell
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include config.mk # 里面会包含arch/arm/config.mk(含有ALL-y += u-boot-dtb.imx)
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%.imx: %.bin
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$(Q)$(MAKE) $(build)=arch/arm/imx-common $@
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```
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u-boot-dtb.imx依赖于u-boot-dtb.bin，u-boot-dtb.bin又依赖于u-boot-nodtb.bin和dts/dt.dtb。
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在顶层Makefile里：
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```shell
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u-boot-dtb.bin: u-boot-nodtb.bin dts/dt.dtb FORCE
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$(call if_changed,cat)
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u-boot-nodtb.bin: u-boot FORCE
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$(call if_changed,objcopy)
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$(call DO_STATIC_RELA,$<,$@,$(CONFIG_SYS_TEXT_BASE))
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$(BOARD_SIZE_CHECK)
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```
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所以，编译出u-boot后，会先制作u-boot-nodtb.bin；然后编译dts/dt.dtb；最后生成u-boot-dtb.bin、imx文件：
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### 5.3.6 编译设备树
|
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顶层Makefile里：
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```shell
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dts/dt.dtb: checkdtc u-boot
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$(Q)$(MAKE) $(build)=dts dtbs
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```
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需要用到scripts/Makefile.build中，它会包含 dts/Makefile， dts/Makefile中含有dtbs目标：
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|
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```shell
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DEVICE_TREE ?= $(CONFIG_DEFAULT_DEVICE_TREE:"%"=%)
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DTB := arch/$(ARCH)/dts/$(DEVICE_TREE).dtb # 就是 arch/arm/dts/imx6ull-14x14-evk.dtb
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|
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$(obj)/dt.dtb: $(DTB) FORCE
|
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$(call if_changed,shipped)
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|
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targets += dt.dtb
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|
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$(DTB): arch-dtbs
|
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$(Q)test -e $@ || ( \
|
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echo >&2; \
|
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echo >&2 "Device Tree Source is not correctly specified."; \
|
||||
echo >&2 "Please define 'CONFIG_DEFAULT_DEVICE_TREE'"; \
|
||||
echo >&2 "or build with 'DEVICE_TREE=<device_tree>' argument"; \
|
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echo >&2; \
|
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/bin/false)
|
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|
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arch-dtbs:
|
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$(Q)$(MAKE) $(build)=arch/$(ARCH)/dts dtbs
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|
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.SECONDARY: $(obj)/dt.dtb.S
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|
||||
obj-$(CONFIG_OF_EMBED) := dt.dtb.o
|
||||
|
||||
dtbs: $(obj)/dt.dtb
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||||
@:
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||||
```
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||||
|
||||
|
||||
|
||||
最后会使用`$(Q)$(MAKE) $(build)=arch/$(ARCH)/dts dtbs`来处理，进入：使用arch/arm/dts/Makefile，里面定了dtb-y：
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||||
|
||||
```shell
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dtb-$(CONFIG_MX6) += imx6ul-14x14-ddr3-arm2.dtb \
|
||||
imx6ul-14x14-ddr3-arm2-emmc.dtb \
|
||||
imx6ul-14x14-ddr3-arm2-gpmi-weim.dtb \
|
||||
imx6ul-14x14-lpddr2-arm2.dtb \
|
||||
imx6ul-14x14-evk.dtb \
|
||||
imx6ul-14x14-evk-emmc.dtb \
|
||||
|
||||
PHONY += dtbs
|
||||
dtbs: $(addprefix $(obj)/, $(dtb-y))
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||||
@:
|
||||
```
|
||||
|
||||
|
||||
|
||||
要编译出各类dtb文件，用到scripts/Makefile.lib，规则如下：
|
||||
|
||||
```shell
|
||||
quiet_cmd_dtc = DTC $@
|
||||
# Modified for U-Boot
|
||||
# Bring in any U-Boot-specific include after the '/dts-v1/;' header
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cmd_dtc = mkdir -p $(dir ${dtc-tmp}) ; \
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cat $< $(if $(u_boot_dtsi),\
|
||||
| sed '/^\/ {$$/{x;s%$$%\#include \"$(u_boot_dtsi)\"%;G;}') | \
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||||
$(CPP) $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) - ; \
|
||||
$(DTC) -O dtb -o $@ -b 0 \
|
||||
-i $(dir $<) $(DTC_FLAGS) \
|
||||
-d $(depfile).dtc.tmp $(dtc-tmp) ; \
|
||||
cat $(depfile).pre.tmp $(depfile).dtc.tmp > $(depfile)
|
||||
|
||||
$(obj)/%.dtb: $(src)/%.dts FORCE
|
||||
$(call if_changed_dep,dtc)
|
||||
```
|
||||
|
||||
|
||||
|
||||
### 5.3.7 制作映像文件
|
||||
|
||||
当制作出设备树文件后，在顶层Makefile里有如下规则，进而制作出u-boot-dtb.bin：
|
||||
|
||||
```shell
|
||||
u-boot-dtb.bin: u-boot-nodtb.bin dts/dt.dtb FORCE
|
||||
$(call if_changed,cat)
|
||||
```
|
||||
|
||||
|
||||
|
||||
回到顶层Makefile，看看如何制作imx映像文件：
|
||||
|
||||
```shell
|
||||
include config.mk # 里面会包含arch/arm/config.mk(含有ALL-y += u-boot-dtb.imx)
|
||||
|
||||
%.imx: %.bin
|
||||
$(Q)$(MAKE) $(build)=arch/arm/imx-common $@
|
||||
```
|
||||
|
||||
现在u-boot-dtb.imx的依赖文件u-boot-dtb.bin已经生成了，将会使用arch/arm/imx-common/Makefile来生产imx文件：
|
||||
|
||||
```shell
|
||||
u-boot.imx: u-boot.bin $(IMX_CONFIG) $(PLUGIN).bin FORCE
|
||||
$(call if_changed,mkimage)
|
||||
```
|
||||
|
||||
最后会使用如下命令生产imx映像文件：
|
||||
|
||||
```shell
|
||||
./tools/mkimage -n board/freescale/mx6ullevk/imximage.cfg.cfgtmp -T imximage -e 0x87800000 -d u-boot-dtb.bin u-boot-dtb.imx
|
||||
```
|
||||
|
||||
|
||||
|
||||
## 5.4 配置编译过程(STM32MP157)
|
||||
|
||||
使用如下命令配置、编译STM32MP157的u-boot：
|
||||
|
||||
```shell
|
||||
make stm32mp15_trusted_defconfig
|
||||
make
|
||||
```
|
||||
|
||||
所涉及的配置过程、编译过程，跟前面分析的IMX6ULL几乎一样。
|
||||
|
||||
|
||||
|
||||
### 5.4.1 配置过程总结
|
||||
|
||||
|
||||
|
||||
### 5.4.2 编译过程总结
|
||||
|
||||
|
||||
|
||||
结论：
|
||||
|
||||
* 执行make命令时，要编译得到哪些文件由`ALL-y`决定
|
||||
|
||||
* 规则如下
|
||||
|
||||
```shell
|
||||
include config.mk # 里面会包含arch/arm/config.mk
|
||||
# arch/arm/Makefile又包含$(machdirs)/config.mk
|
||||
# 就是包含 arch/arm/mach-stm32mp/config.mk
|
||||
# 里面有 ALL-y += u-boot.stm32
|
||||
|
||||
_all : all
|
||||
|
||||
# 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_OF_SEPARATE) += u-boot.dtb
|
||||
|
||||
all: $(ALL-y)
|
||||
```
|
||||
|
||||
* `ALL-y`的值为：
|
||||
|
||||
```shell
|
||||
checkarmreloc u-boot.stm32 u-boot.srec u-boot.bin u-boot.sym System.map binary_size_check u-boot.dtb
|
||||
```
|
||||
|
||||
|
||||
|
||||
|
||||
* u-boot.stm32依赖于u-boot.bin
|
||||
|
||||
* u-boot.bin依赖于u-boot-dtb.bin
|
||||
* u-boot-dtb.bin依赖于u-boot-nodtb.bin和dts/dt.dtb
|
||||
|
||||
* 各类u-boot文件都依赖于u-boot，先编译得到u-boot，它由`u-boot-init`、`u-boot-main`两部分链接而成
|
||||
|
||||
* u-boot-init为：arch/arm/cpu/armv7/start.o
|
||||
|
||||
* u-boot-main为：lib/built-in.o fs/built-in.o net/built-in.o 等等
|
||||
|
||||
* 如何编译各个built-in.o，以lib/built-in.o为例
|
||||
|
||||
* 执行: ``make -f ./scripts/Makefile.build obj=lib`
|
||||
* 会包含lib/Makefile，里面定义了`obj-y`
|
||||
* 使用Makefile.build的规则把各个obj-y编译、链接为built-in.o
|
||||
|
||||
* 使用如下的命令链接得到u-boot：
|
||||
|
||||
```shell
|
||||
quiet_cmd_u-boot__ ?= LD $@
|
||||
cmd_u-boot__ ?= $(LD) $(LDFLAGS) $(LDFLAGS_u-boot) -o $@ \
|
||||
-T u-boot.lds $(u-boot-init) \
|
||||
--start-group $(u-boot-main) --end-group \
|
||||
$(PLATFORM_LIBS) -Map u-boot.map
|
||||
```
|
||||
|
||||
* 再编译得到设备树文件: `make -f ./scripts/Makefile.build obj=dts dtbs`
|
||||
|
||||
* 顶层Makefile如下：
|
||||
|
||||
```shell
|
||||
dts/dt.dtb: checkdtc u-boot
|
||||
$(Q)$(MAKE) $(build)=dts dtbs
|
||||
```
|
||||
|
||||
* scripts/Makefile.build中，会包含 dts/Makefile
|
||||
|
||||
```shell
|
||||
DTB := arch/$(ARCH)/dts/$(DEVICE_TREE).dtb
|
||||
|
||||
$(DTB): arch-dtbs
|
||||
$(obj)/dt.dtb: $(DTB) FORCE
|
||||
$(call if_changed,shipped)
|
||||
|
||||
targets += dt.dtb
|
||||
|
||||
$(DTB): arch-dtbs
|
||||
$(Q)test -e $@ || ( \
|
||||
echo >&2; \
|
||||
echo >&2 "Device Tree Source is not correctly specified."; \
|
||||
echo >&2 "Please define 'CONFIG_DEFAULT_DEVICE_TREE'"; \
|
||||
echo >&2 "or build with 'DEVICE_TREE=<device_tree>' argument"; \
|
||||
echo >&2; \
|
||||
/bin/false)
|
||||
|
||||
arch-dtbs:
|
||||
$(Q)$(MAKE) $(build)=arch/$(ARCH)/dts dtbs
|
||||
|
||||
.SECONDARY: $(obj)/dt.dtb.S
|
||||
|
||||
obj-$(CONFIG_OF_EMBED) := dt.dtb.o
|
||||
|
||||
dtbs: $(obj)/dt.dtb
|
||||
@:
|
||||
```
|
||||
|
||||
|
||||
|
||||
* 最后制作u-boot.stm32，在arch/arm/mach-stm32mp/config.mk中有如下规则：
|
||||
|
||||
```shell
|
||||
u-boot.stm32: u-boot.bin FORCE
|
||||
$(call if_changed,mkimage)
|
||||
```
|
||||
|
||||
* if_changed函数在scripts/Kbuild.include中定义：
|
||||
|
||||
```shell
|
||||
if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
|
||||
@set -e; \
|
||||
$(echo-cmd) $(cmd_$(1)); \
|
||||
printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
|
||||
```
|
||||
|
||||
* 展开`$(call if_changed,mkimage)`，就是执行如下命令：
|
||||
|
||||
```shell
|
||||
cmd_mkimage
|
||||
```
|
||||
|
||||
* cmd_mkimage命令在顶层Makefile中定义：
|
||||
|
||||
```shell
|
||||
cmd_mkimage = $(objtree)/tools/mkimage $(MKIMAGEFLAGS_$(@F)) -d $< $@ \
|
||||
```
|
||||
|
||||
|
||||
|
||||
|
||||
BIN
09_u-boot完全分析与移植/doc_pic/pic/12_create_imx.png
Normal file
BIN
09_u-boot完全分析与移植/doc_pic/pic/12_create_imx.png
Normal file
Binary file not shown.
|
After Width: | Height: | Size: 114 KiB |
BIN
09_u-boot完全分析与移植/doc_pic/pic/13_u-boot_stm32mp157_cfg.png
Normal file
BIN
09_u-boot完全分析与移植/doc_pic/pic/13_u-boot_stm32mp157_cfg.png
Normal file
Binary file not shown.
|
After Width: | Height: | Size: 4.5 MiB |
BIN
09_u-boot完全分析与移植/doc_pic/pic/14_create_stm32.png
Normal file
BIN
09_u-boot完全分析与移植/doc_pic/pic/14_create_stm32.png
Normal file
Binary file not shown.
|
After Width: | Height: | Size: 172 KiB |
Reference in New Issue
Block a user