在Linux下面，要分析一个项目，首先应该读Makefile。前面有了一定的Makefile基础，现在虽然还不能写复杂的Makefile脚本，但是参考资料，还可以读懂vivi的Makefile。不过vivi的Makefile给我的感觉是在组织上有点凌乱，读起来有点费劲。只有真正理解了这个项目的组织，才能明白凌乱在何处。这中间都是按照自己的认识过程，尝试了各种方法来分析，基本上完成了按照自己理解改写的Makefile。编译完成重新下载到nand flash里面，验证没有问题。
下面首先给出改写的Makefile。我尝试使用英语注释，可能不太通顺。但是，第一步总是要迈出的，早总比晚要好。
| # Modified by Qingmin Liu(piaoxiangxinling@163.com, Shandong University)
# Date: 2007-07-26
# Desc: This document is only used for studying. If you want to talk about
# vivi or embedded system, I am very glad to receive your email.
#
# Section 1: vivi version
#
# 3 rows below supplies with a numbering scheme, which comes from Linux
# kernel. This numbering scheme uses three numbers separated by dots to
# identify the releases. The first number designates the version, the
# second designates the patch, and the third designates the release.
#
# Usually, you should use a kernel from the latest stable series for your
# embedded system.
VERSION = 0
PATCHLEVEL = 1
SUBLEVEL = 4
# This macro definations is used to supply users with version information,
# and you will find the usage in [init/version.c]. If you port vivi to your
# own board successfully, the version information displays at the beginning
# through the debug serial.
#
# VIVIRELEASE = 0.1.4
VIVIRELEASE=$(VERSION).$(PATCHLEVEL).$(SUBLEVEL)
#
# Section 2: target architecture
#
# Architecture is arm. If you don't understand architecture, I think, you'd
# better search some data on the internet.
ARCH := arm
#
# Section 3: tools
#
# CONFIG_SHELL gets the shell that is used on your host. In my host, OS is
# Redhat Linux 9.0, and bash shell is the default one.
#
# This is used to execute the config scripts in [scripts]. And this is vivi's
# core about interactive configuration.
#
# You need to know some about Makefile if you don't know $(shell ..). In fact,
# it works to search the shell: /bin/bash --> sh. In my host, it works well.
# for example,
# $which bash
# /bin/bash
# $which sh
# /bin/sh
CONFIG_SHELL := $(shell if [ -x /bin/bash ]; then echo /bin/bash; \
else echo /bin/sh; fi)
# HOST tool
HOSTCC = gcc
HOSTCFLAGS = -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
export HOSTCC HOSTCFLAGS
# TARGET tool
CROSS_COMPILE = /usr/local/arm/2.95.3/bin/arm-linux-
AS = $(CROSS_COMPILE)as
LD = $(CROSS_COMPILE)ld
CC = $(CROSS_COMPILE)gcc
CPP = $(CC) -E
AR = $(CROSS_COMPILE)ar
NM = $(CROSS_COMPILE)nm
STRIP = $(CROSS_COMPILE)strip
OBJCOPY = $(CROSS_COMPILE)objcopy
OBJDUMP = $(CROSS_COMPILE)objdump
export AS LD CC CPP AR
#
# Section 4: parameters
#
# TOPDIR means top directory of your project. More accurately, it means the
# directory of "Makefile" because you must step into the directory of Makefile
# if you want to execute make on your command line.
TOPDIR := $(shell if [ "$$PWD" != "" ]; then echo $$PWD;else /bin/pwd; fi)
export TOPDIR
# standard CFLAGS
CPPFLAGS := -I$(TOPDIR)/include
CFLAGS := $(CPPFLAGS) -Wall -Wstrict-prototypes -O2 -fPIC -fomit-frame-pointer
AFLAGS := -D__ASSEMBLY__ $(CPPFLAGS)
export CFLAGS AFLAGS
# Location of the gcc arm libs.
ARM_GCC_LIBS = /usr/local/arm/2.95.3/lib/gcc-lib/arm-linux/2.95.3
OBJCOPYFLAGS = -R .comment -R .stab -R .stabstr
CLIBS = -L$(ARM_GCC_LIBS) -lgcc -lc
LINKFLAGS = -Tarch/vivi.lds -Bstatic
#
# Section 5: files that will be included or handled with.
#
# whe you execute make on the command line, MAKEFILES are read at first.
MAKEFILES = $(TOPDIR)/.config
# core files and so on
CORE_FILES = init/main.o init/version.o lib/lib.o
LIBS := lib/priv_data/priv_data.o
SUBDIRS = drivers lib
# files that will be deleted when "make clean"
CLEAN_FILES = \
vivi-elf \
vivi \
vivi.nm \
vivi.map
# files that will be deleted when "make distclean"
DISTCLEAN_FILES = \
include/autoconf.h .menuconfig.log \
scripts/lxdialog/*.o scripts/lxdialog/lxdialog \
.config .config.old TAGS tags
#
# Section 6: drivers added
#
# define CONFIGURATION if .config exists;
# else include .config
ifeq (.config, $(wildcard .config))
include .config
else
CONFIGURATION = config
endif
# drivers added by .config setup
# if CONFIG_SERIAL=y and CONFIG_MTD=y, DRIVERS equals "drivers/serial/serial.o drivers/mtd/mtd.o"
DRIVERS-y :=
DRIVERS-$(CONFIG_SERIAL) += drivers/serial/serial.o
DRIVERS-$(CONFIG_MTD) += drivers/mtd/mtd.o
DRIVERS := $(DRIVERS-y)
#
# Section 7: sub Makefile
#
include arch/Makefile
#
# Section 8: real handle
#
.PHONY: all do-it-all
# make all
# execute all handle procedure by the config
all: do-it-all
# search .config.If it exists, read .config first and equals "make Version; make vivi".
# else define CONFIGURATION and it equals "make config"
ifdef CONFIGURATION
do-it-all: $(CONFIGURATION)
else
do-it-all: Version vivi
endif
# make Version
# delete [include/compile.h]
Version:
$(RM) include/compile.h
# make vivi
# create target file -- vivi
# please remember: prerequisites in sequence.
vivi: $(CONFIGURATION) init/main.o init/version.o linuxsubdirs
$(LD) -v $(LINKFLAGS) \
$(HEAD) \
$(CORE_FILES) \
$(DRIVERS) \
$(LIBS) \
-o $@-elf $(CLIBS)
$(NM) -v -l $@-elf > $@.map
$(OBJCOPY) -O binary -S $@-elf $@ $(OBJCOPYFLAGS)
@echo
@echo " ^_^ The vivi boot image file is: $(shell pwd)/$@, and you \
can download it to your [nor | nand] flash."
@echo
# make oldconfig
# configure by the .config
oldconfig:
$(CONFIG_SHELL) scripts/Configure -d arch/config.in
# make config
# configure by the [arch/defconfig]
config:
$(CONFIG_SHELL) scripts/Configure arch/config.in
# make menuconfig
# configure in forms of menutext
menuconfig:
$(MAKE) -C scripts/lxdialog all
$(CONFIG_SHELL) scripts/Menuconfig arch/config.in
# make clean
# delete middle files
clean:
find . \( -name '*.o' -o -name core -o -name ".*.flags" \) -type f -print \
| grep -v lxdialog/ | xargs rm -f
$(RM) $(CLEAN_FILES)
# make distclean
# delete middle files and configure files
distclean: Version clean
$(RM) $(DISTCLEAN_FILES)
# make myboard_config
# Configuration targets. Use these to select a
# configuration for your architecture
#
# here, @ makes the command no echo back.and "CFG=$(@:_config=)" uses the advanced
# function of variables.for example,
# foo:=a.o b.o c.o
# bar:=$(foo:.o=.c)
# so bar = a.c b.c c.c
%_config:
@ ( \
CFG=$(@:_config=); \
if [ -f arch/def-configs/$$CFG ]; then \
[ -f .config ] && mv -f .config .config.old; \
cp arch/def-configs/$$CFG .config; \
echo "*** Default configuration for $$CFG installed";\
echo "*** Next, you may run 'make oldconfig'"; \
else \
echo "$$CFG does not exist"; \
fi; \
)
# make myboard
# make your work automatically
%: ./arch/def-configs/%
$(MAKE) distclean
cp arch/def-configs/$* ./.config -f
$(MAKE) oldconfig
$(MAKE)
#
# Section 9: real handle prerequisites
#
# read SUBDIRS
# here SUBDIRS = drivers lib
linuxsubdirs: $(patsubst %, _dir_%, $(SUBDIRS))
# read sub Makefile in SUBDIRS
$(patsubst %, _dir_%, $(SUBDIRS)) :
$(MAKE) CFLAGS="$(CFLAGS) $(CFLAGS_KERNEL)" -C $(patsubst _dir_%, %, $@)
# create [include/compile.h]
include/compile.h: $(CONFIGURATION)
@echo \#define VIVI_RELEASE \"$(VIVIRELEASE)\" > .ver
@echo -n \#define UTS_VERSION \"\#$(VIVIRELEASE) >> .ver
@if [ -f .name ]; then echo -n \-`cat .name` >> .ver; fi
@echo ' '`date`'"' >> .ver
@echo \#define VIVI_COMPILE_BY \"`whoami`\" >> .ver
@echo \#define VIVI_COMPILE_HOST \"`hostname`\" >> .ver
@echo \#define VIVI_COMPILER \"`$(CC) $(CFLAGS) -v 2>&1 | tail -1`\" >> .ver
@mv -f .ver $@
# compile [init/version.c]
init/version.o: init/version.c include/compile.h
$(CC) $(CFLAGS) -DUTS_MACHINE='"$(ARCH)"' -c $< -o $@
# compile [init/main.c]
init/main.o: init/main.c
$(CC) $(CFLAGS) $(CFLAGS_KERNEL) $(PROFILING) -c $< -o $@
# create TAGS
TAGS:
etags `find include -name '*.h'`
find $(SUBDIRS) init -name '*.[ch]' | xargs etags -a
# Exuberant ctags works better with -I
tags:
CTAGSF=`ctags --version | grep -i exuberant >/dev/null && \
echo "-I __initdata,__exitdata,EXPORT_SYMBOL,EXPORT_SYMBOL_NOVERS"`; \
ctags $$CTAGSF `find include -name '*.h'` && \
find $(SUBDIRS) init -name '*.[ch]' | xargs ctags $$CTAGSF -a
#
# Section 10: default rules
#
include Rules.make
#
# Section 11: debug
#
debug:
@echo "VIVIRELEASE: $(VIVIRELEASE)"
@echo "ARCH: $(ARCH)"
@echo "CONFIG_SHELL: $(CONFIG_SHELL)"
@echo "CROSS_COMPILE: $(CROSS_COMPILE)"
@echo "TOPDIR: $(TOPDIR)"
@echo "SUBDIRS: $(SUBDIRS)"
@echo "CONFIGURATION: $(CONFIGURATION)"
@echo "DRIVERS: $(DRIVERS)"
|
修改的幅度比较大，但是这样组织之后，清晰了很多，至少我是这样感觉。现在一般的命令处理有：
make clean：清理中间生成文件，不包括配置文件
make distclean：清理所有生成文件
make config：文本配置，如果没有[.config]，默认读取[arch/defconfig]
make oldconfig: 文本配置，默认读取[.config]
make menuconfig：图像配置，需要图形库的支持
make debug：变量调试
make vivi：编译，生成目标文件
make myboard_config：假设我的配置保存为[arch/def-configs/myboard]，那么此命令的结果是把该配置复制到[.config]。如果原来存在[.config]，则把原来的[.config]更改为[.config.old].
make myboard：假设我的配置保存为[arch/def-configs/myboard]，那么此命令实现了自动化编译。首先清理所有的生成文件，然后把myboard读取到[.config]，根据此配置编译生成最终的vivi目标文件。
我常用的做法是：(1)make smdk2410_config(2)make menuconfig(3)make vivi(4)cp .config ./arch/def-configs/myboard.如果以后改变程序，而不改变配置，就可以执行make distclean.理解了整个过程，对这些就可以熟练应用了。也可以自己添加适合自己的编译命令。
Makefile采用了主Makefile和子Makefile配合的方式，它们之间的联系如下：
首先，读取主Makefile，主Makefile通过该"include arch/Makefile"完成包含，主要是一些相关的配置。至于其他的子Makefile，在执行make vivi时，有依赖关系linuxsubdirs，这个部分就是完成读取并完成所有其他子Makefile.具体就在下面语句。
linuxsubdirs: $(patsubst %, _dir_%, $(SUBDIRS))
# read sub Makefile in SUBDIRS
$(patsubst %, _dir_%, $(SUBDIRS)) :
$(MAKE) CFLAGS="$(CFLAGS) $(CFLAGS_KERNEL)" -C $(patsubst _dir_%, %, $@)
所有的显示规则和隐式规则都在Rules.make里，也是用include引入，这样就形成了一条链，完美的管理着你的项目。另外，配置部分需要在另外一篇文档中总结。需要读scripts下的脚本，现在还没有读完。
相对于vivi原始工程，做了一个patch。
 | | 文件: | patch.rar | | 大小: | 6KB | | 下载: | 下载 | |
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