我是靠谱客的博主 不安芒果，最近开发中收集的这篇文章主要介绍深入浅析Linux下uboot之（三）-----------------------：Makefile分析，觉得挺不错的，现在分享给大家，希望可以做个参考。
概述
Makefile 是配置整个 uboot 的关键。
VERSION = 2
PATCHLEVEL = 3
SUBLEVEL = 4
EXTRAVERSION =
U_BOOT_VERSION = $(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)
VERSION_FILE = $(obj)include/version_autogenerated.h真正开始的是从这段代码开始，这段代码是生成uboot的版本号：
- VERSION：主板本号
PATCHLEVEL：次版本号
SUBLEVEL：再次版本号
EXTRAVERSION:另外附加的版本信息 - include/version_autogenerated.h文件是编译过程中自动生成的一个文件，所以源目录中没有，但是编译过后的uboot中就有了。它里面的内容是一个宏定义，宏定义的值内容就是我们在Makefile中配置的uboot的版本号。
最终uboot会生成 “2.3.4Croxd”。
HOSTARCH := $(shell uname -m |
sed -e s/i.86/i386/
-e s/sun4u/sparc64/
-e s/arm.*/arm/
-e s/sa110/arm/
-e s/powerpc/ppc/
-e s/ppc64/ppc/
-e s/macppc/ppc/)
HOSTOS := $(shell uname -s | tr '[:upper:]' '[:lower:]' |
sed -e 's/(cygwin).*/cygwin/')- HOSTARCH：HOST是主机，就是当前在做开发用的这台电脑就叫主机；ARCH是architecture(架构)的缩写，表示CPU的架构。所以HOSTARCH就表示主机的CPU的架构。
- HOSTOS：主机的操作系统。
# Allow for silent builds
ifeq (,$(findstring s,$(MAKEFLAGS)))
XECHO = echo
else
XECHO = :
endif- 静默编译：平时默认编译时命令行会打印出来很多编译信息。但是有时候我们不希望看到这些编译信息，就后台编译即可。这就叫静默编译。使用方法就是编译时make -s，-s会作为MAKEFLAGS传给Makefile，这段代码作用下XECHO变量就会被变成空（默认等于echo），于是实现了静默编译。
ifdef O
ifeq ("$(origin O)", "command line")
BUILD_DIR := $(O)
endif
endif
ifneq ($(BUILD_DIR),)
saved-output := $(BUILD_DIR)
# Attempt to create a output directory.
$(shell [ -d ${BUILD_DIR} ] || mkdir -p ${BUILD_DIR})
# Verify if it was successful.
BUILD_DIR := $(shell cd $(BUILD_DIR) && /bin/pwd)
$(if $(BUILD_DIR),,$(error output directory "$(saved-output)" does not exist))
endif # ifneq ($(BUILD_DIR),)
OBJTREE := $(if $(BUILD_DIR),$(BUILD_DIR),$(CURDIR))
SRCTREE := $(CURDIR)
TOPDIR := $(SRCTREE)
LNDIR := $(OBJTREE)
export TOPDIR SRCTREE OBJTREE
MKCONFIG := $(SRCTREE)/mkconfig
export MKCONFIG
ifneq ($(OBJTREE),$(SRCTREE))
REMOTE_BUILD := 1
export REMOTE_BUILD
endif
# $(obj) and (src) are defined in config.mk but here in main Makefile
# we also need them before config.mk is included which is the case for
# some targets like unconfig, clean, clobber, distclean, etc.
ifneq ($(OBJTREE),$(SRCTREE))
obj := $(OBJTREE)/
src := $(SRCTREE)/
else
obj :=
src :=
endif
export obj src
# Make sure CDPATH settings don't interfere
unexport CDPATH- 这段代码主要实现的是单独输出文件夹编译：在编译复杂项目，Makefile提供2种编译管理方法。默认情况下是当前文件夹中的.c文件，编译出来的.o文件会放在同一文件夹下。这种方式叫原地编译。另一种方法是单独输出文件夹方式的编译（linux kernel也支持，而且uboot的这种技术就是从linux kernel学习来的）。基本思路就是在编译时另外指定一个输出目录，将来所有的编译生成的.o文件或生成的其他文件全部丢到那个输出目录下去。
- 单独输出文件夹编译方法：默认的就是原地编译。如果需要指定具体的输出目录编译则有2种方式来指定输出目录：第一种：make O=输出目录 ，第二种：export BUILD_DIR=输出目录 然后再make。如果两个都指定了（既有BUILD_DIR环境变量存在，又有O=xx），则O=xx具有更高优先级，听他的。
- OBJTREE：编译出的.o文件存放的目录的根目录。在默认编译下，OBJTREE等于当前目录；在O=xx编译下，OBJTREE就等于我们设置的那个输出目录。
- SRCTREE: 源码目录，其实就是源代码的根目录，也就是当前目录。
- MKCONFIG：Makefile中定义的一个变量（在这里定义，在后面使用），它的值就是我们源码根目录下面的mkconfig。这个mkconfig是一个脚本，这个脚本就是uboot配置阶段的配置脚本。
# load ARCH, BOARD, and CPU configuration
include $(obj)include/config.mk
export ARCH CPU BOARD VENDOR SOC
ifndef CROSS_COMPILE
ifeq ($(HOSTARCH),$(ARCH))
CROSS_COMPILE =
else
ifeq ($(ARCH),ppc)
CROSS_COMPILE = ppc_8xx-
endif
ifeq ($(ARCH),arm)
#CROSS_COMPILE = arm-linux-
#CROSS_COMPILE = /usr/local/arm/4.4.1-eabi-cortex-a8/usr/bin/arm-linux-
#CROSS_COMPILE = /usr/local/arm/4.2.2-eabi/usr/bin/arm-linux-
CROSS_COMPILE = /usr/local/arm/arm-2009q3/bin/arm-none-linux-gnueabi-
endif
ifeq ($(ARCH),i386)
CROSS_COMPILE = i386-linux-
endif
ifeq ($(ARCH),mips)
CROSS_COMPILE = mips_4KC-
endif
ifeq ($(ARCH),nios)
CROSS_COMPILE = nios-elf-
endif
ifeq ($(ARCH),nios2)
CROSS_COMPILE = nios2-elf-
endif
ifeq ($(ARCH),m68k)
CROSS_COMPILE = m68k-elf-
endif
ifeq ($(ARCH),microblaze)
CROSS_COMPILE = mb-
endif
ifeq ($(ARCH),blackfin)
CROSS_COMPILE = bfin-uclinux-
endif
ifeq ($(ARCH),avr32)
CROSS_COMPILE = avr32-linux-
endif
ifeq ($(ARCH),sh)
CROSS_COMPILE = sh4-linux-
endif
ifeq ($(ARCH),sparc)
CROSS_COMPILE = sparc-elf-
endif # sparc
endif # HOSTARCH,ARCH
endif # CROSS_COMPILE
export CROSS_COMPILE- include $(obj)include/config.mk：include/config.mk不是源码自带的（你在没有编译过的源码目录下是找不到这个文件的），要在配置过程（make x210_sd_config）中才会生成这个文件。因此这个文件的值和我们配置过程有关，是由配置过程根据我们的配置自动生成的。如：ARCH = arm、CPU = s5pc11x、BOARD = x210、VENDOR = samsung
、OC = s5pc110 ，配置值来自于Makefile ：@$(MKCONFIG) $(@:_config=) arm s5pc11x x210 samsung s5pc110 - ARCH：定义当前编译的目标CPU的架构，它的值会影响后面的CROSS_COMPILE环境变量的值。
- CROSS_COMPILE：定义交叉编译工具链的前缀的。CROSS_COMPILE是被ARCH所确定的，只要配置了ARCH=arm，那么我们就只能在ARM的那个分支去设置CROSS_COMPILE的值。实际运用时，我们可以在Makefile中去更改设置CROSS_COMPILE的值，也可以在编译时用make CROSS_COMPILE=xxxx来设置，而且编译时传参的方法可以覆盖Makefile里面的设置。
# load other configuration
include $(TOPDIR)/config.mk- 接下来是会用到当前目录下的 config.mk ，config.mk的内容如下：
-
# # (C) Copyright 2000-2006 # Wolfgang Denk, DENX Software Engineering, wd@denx.de. # # See file CREDITS for list of people who contributed to this # project. # # This program is free software; you can redistribute it and/or # modify it under the terms of the GNU General Public License as # published by the Free Software Foundation; either version 2 of # the License, or (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, # MA 02111-1307 USA # ######################################################################### ifneq ($(OBJTREE),$(SRCTREE)) ifeq ($(CURDIR),$(SRCTREE)) dir := else dir := $(subst $(SRCTREE)/,,$(CURDIR)) endif obj := $(if $(dir),$(OBJTREE)/$(dir)/,$(OBJTREE)/) src := $(if $(dir),$(SRCTREE)/$(dir)/,$(SRCTREE)/) $(shell mkdir -p $(obj)) else obj := src := endif # clean the slate ... PLATFORM_RELFLAGS = PLATFORM_CPPFLAGS = PLATFORM_LDFLAGS = # # When cross-compiling on NetBSD, we have to define __PPC__ or else we # will pick up a va_list declaration that is incompatible with the # actual argument lists emitted by the compiler. # # [Tested on NetBSD/i386 1.5 + cross-powerpc-netbsd-1.3] ifeq ($(ARCH),ppc) ifeq ($(CROSS_COMPILE),powerpc-netbsd-) PLATFORM_CPPFLAGS+= -D__PPC__ endif ifeq ($(CROSS_COMPILE),powerpc-openbsd-) PLATFORM_CPPFLAGS+= -D__PPC__ endif endif ifeq ($(ARCH),arm) ifeq ($(CROSS_COMPILE),powerpc-netbsd-) PLATFORM_CPPFLAGS+= -D__ARM__ endif ifeq ($(CROSS_COMPILE),powerpc-openbsd-) PLATFORM_CPPFLAGS+= -D__ARM__ endif endif ######################################################################### CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; else if [ -x /bin/bash ]; then echo /bin/bash; else echo sh; fi ; fi) ifeq ($(HOSTOS)-$(HOSTARCH),darwin-ppc) HOSTCC = cc else HOSTCC = gcc endif HOSTCFLAGS = -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer HOSTSTRIP = strip ######################################################################### # # Option checker (courtesy linux kernel) to ensure # only supported compiler options are used # cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;) # # Include the make variables (CC, etc...) # AS = $(CROSS_COMPILE)as LD = $(CROSS_COMPILE)ld CC = $(CROSS_COMPILE)gcc CPP = $(CC) -E AR = $(CROSS_COMPILE)ar NM = $(CROSS_COMPILE)nm LDR = $(CROSS_COMPILE)ldr STRIP = $(CROSS_COMPILE)strip OBJCOPY = $(CROSS_COMPILE)objcopy OBJDUMP = $(CROSS_COMPILE)objdump RANLIB = $(CROSS_COMPILE)RANLIB ######################################################################### # Load generated board configuration sinclude $(OBJTREE)/include/autoconf.mk ifdef ARCH sinclude $(TOPDIR)/$(ARCH)_config.mk # include architecture dependend rules endif ifdef CPU sinclude $(TOPDIR)/cpu/$(CPU)/config.mk # include CPU specific rules endif ifdef SOC sinclude $(TOPDIR)/cpu/$(CPU)/$(SOC)/config.mk # include SoC specific rules endif ifdef VENDOR BOARDDIR = $(VENDOR)/$(BOARD) else BOARDDIR = $(BOARD) endif ifdef BOARD sinclude $(TOPDIR)/board/$(BOARDDIR)/config.mk # include board specific rules endif ######################################################################### ifneq (,$(findstring s,$(MAKEFLAGS))) ARFLAGS = cr else ARFLAGS = crv endif RELFLAGS= $(PLATFORM_RELFLAGS) DBGFLAGS= -g # -DDEBUG OPTFLAGS= -Os #-fomit-frame-pointer ifndef LDSCRIPT #LDSCRIPT := $(TOPDIR)/board/$(BOARDDIR)/u-boot.lds.debug #------------------------ 1 ---------------------------- ifeq ($(CONFIG_NAND_U_BOOT),y) LDSCRIPT := $(TOPDIR)/board/$(BOARDDIR)/u-boot-nand.lds else LDSCRIPT := $(TOPDIR)/board/$(BOARDDIR)/u-boot.lds endif #------------------------ 1 ---------------------------- endif OBJCFLAGS += --gap-fill=0xff gccincdir := $(shell $(CC) -print-file-name=include) CPPFLAGS := $(DBGFLAGS) $(OPTFLAGS) $(RELFLAGS) -D__KERNEL__ #------------------------ 2 ---------------------------- ifneq ($(TEXT_BASE),) CPPFLAGS += -DTEXT_BASE=$(TEXT_BASE) endif #------------------------ 2 ---------------------------- ifneq ($(OBJTREE),$(SRCTREE)) CPPFLAGS += -I$(OBJTREE)/include2 -I$(OBJTREE)/include endif CPPFLAGS += -I$(TOPDIR)/include CPPFLAGS += -fno-builtin -ffreestanding -nostdinc -isystem $(gccincdir) -pipe $(PLATFORM_CPPFLAGS) ifdef BUILD_TAG CFLAGS := $(CPPFLAGS) -Wall -Wstrict-prototypes -DBUILD_TAG='"$(BUILD_TAG)"' else CFLAGS := $(CPPFLAGS) -Wall -Wstrict-prototypes endif CFLAGS += $(call cc-option,-fno-stack-protector) # avoid trigraph warnings while parsing pci.h (produced by NIOS gcc-2.9) # this option have to be placed behind -Wall -- that's why it is here ifeq ($(ARCH),nios) ifeq ($(findstring 2.9,$(shell $(CC) --version)),2.9) CFLAGS := $(CPPFLAGS) -Wall -Wno-trigraphs endif endif # $(CPPFLAGS) sets -g, which causes gcc to pass a suitable -g<format> # option to the assembler. AFLAGS_DEBUG := # turn jbsr into jsr for m68k ifeq ($(ARCH),m68k) ifeq ($(findstring 3.4,$(shell $(CC) --version)),3.4) AFLAGS_DEBUG := -Wa,-gstabs,-S endif endif AFLAGS := $(AFLAGS_DEBUG) -D__ASSEMBLY__ $(CPPFLAGS) LDFLAGS += -Bstatic -T $(LDSCRIPT) $(PLATFORM_LDFLAGS) ifneq ($(TEXT_BASE),) LDFLAGS += -Ttext $(TEXT_BASE) endif # Location of a usable BFD library, where we define "usable" as # "built for ${HOST}, supports ${TARGET}". Sensible values are # - When cross-compiling: the root of the cross-environment # - Linux/ppc (native): /usr # - NetBSD/ppc (native): you lose ... (must extract these from the # binutils build directory, plus the native and U-Boot include # files don't like each other) # # So far, this is used only by tools/gdb/Makefile. ifeq ($(HOSTOS)-$(HOSTARCH),darwin-ppc) BFD_ROOT_DIR = /usr/local/tools else ifeq ($(HOSTARCH),$(ARCH)) # native BFD_ROOT_DIR = /usr else #BFD_ROOT_DIR = /LinuxPPC/CDK # Linux/i386 #BFD_ROOT_DIR = /usr/pkg/cross # NetBSD/i386 BFD_ROOT_DIR = /opt/powerpc endif endif ifeq ($(PCI_CLOCK),PCI_66M) CFLAGS := $(CFLAGS) -DPCI_66M endif ######################################################################### export CONFIG_SHELL HPATH HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC CPP AR NM STRIP OBJCOPY OBJDUMP MAKE export TEXT_BASE PLATFORM_CPPFLAGS PLATFORM_RELFLAGS CPPFLAGS CFLAGS AFLAGS ######################################################################### ifndef REMOTE_BUILD %.s: %.S $(CPP) $(AFLAGS) -o $@ $< %.o: %.S $(CC) $(AFLAGS) -c -o $@ $< %.o: %.c $(CC) $(CFLAGS) -c -o $@ $< else $(obj)%.s: %.S $(CPP) $(AFLAGS) -o $@ $< $(obj)%.o: %.S $(CC) $(AFLAGS) -c -o $@ $< $(obj)%.o: %.c $(CC) $(CFLAGS) -c -o $@ $< endif ######################################################################### - 前面到107行是具体编译工具的选择。
- sinclude $(OBJTREE)/include/autoconf.mk：autoconfig.mk文件不是源码提供的，是配置过程自动生成的。这个文件的作用就是用来指导整个uboot的编译过程。这个文件的内容其实就是很多CONFIG_开头的宏（可以理解为变量），这些宏/变量会影响我们uboot编译过程的走向（原理就是条件编译）。在uboot代码中有很多地方使用条件编译进行编写，这个条件编译是用来实现可移植性的。这个文件不是凭空产生的，配置过程也是需要原材料来产生这个文件的。原材料在源码目录的inlcude/configs/xxx.h头文件。（X210开发板中为include/configs/x210_sd.h）。这个h头文件里面全都是宏定义，这些宏定义就是我们对当前开发板的移植。每一个开发板的移植都对应这个目录下的一个头文件，这个头文件里每一个宏定义都很重要，这些配置的宏定义就是我们移植uboot的关键所在。
- 文本中 #------------------------ 1 ----------------------------包含的是：uboot的编译链接过程的链接脚本。如果定义了CONFIG_NAND_U_BOOT宏，则链接脚本叫u-boot-nand.lds，如果未定义这个宏则链接脚本叫u-boot.lds。实际在boardsamsungx210目录下有u-boot.lds，这个就是链接脚本。我们在分析uboot的编译链接过程时就要考虑这个链接脚本。
- 文本中 #------------------------ 2 ----------------------------包含的是：TEXT_BASE：Makefile中在配置X210开发板时，在board/samsung/x210目录下生成了一个文件config.mk，其中的内容就是：TEXT_BASE = 0xc3e00000相当于定义了一个变量。TEXT_BASE是将来我们整个uboot链接时指定的链接地址。
接下来回到我们的 Makefile，后面执行的都是目标文件的生成如。还有 unconfig 未配置的内容，用 unconfig 这个符号用来做为我们各个开发板配置目标的依赖。如：
置开发板时使用：make x210_sd_config，因此分析x210_sd_config肯定是主Makefile中的一个目标。
这里传6个参数：$(@:_config=) arm s5pc11x x210 samsung s5pc110。x210_sd_config里的_config部分用空替换，得到：x210_sd，这就是第一个参数，所以：
- $1: x210_sd
- $2: arm
- $3: s5pc11x
- $4: x210
- $5: samsumg
- $6: s5pc110
所以，$# = 6
这几个参数的值是传到和 Makefile 同目录下的 mkconfig 文件里，以下是 mkconfig 的内容：
#!/bin/sh -e
# Script to create header files and links to configure
# U-Boot for a specific board.
#
# Parameters: Target Architecture CPU Board [VENDOR] [SOC]
#
# (C) 2002-2006 DENX Software Engineering, Wolfgang Denk <wd@denx.de>
#
APPEND=no # Default: Create new config file
BOARD_NAME="" # Name to print in make output
while [ $# -gt 0 ] ; do
case "$1" in
--) shift ; break ;;
-a) shift ; APPEND=yes ;;
-n) shift ; BOARD_NAME="${1%%_config}" ; shift ;;
*) break ;;
esac
done
[ "${BOARD_NAME}" ] || BOARD_NAME="$1"
[ $# -lt 4 ] && exit 1
[ $# -gt 6 ] && exit 1
echo "Configuring for ${BOARD_NAME} board..."
#
# Create link to architecture specific headers
#
if [ "$SRCTREE" != "$OBJTREE" ] ; then
mkdir -p ${OBJTREE}/include
mkdir -p ${OBJTREE}/include2
cd ${OBJTREE}/include2
rm -f asm
ln -s ${SRCTREE}/include/asm-$2 asm
LNPREFIX="../../include2/asm/"
cd ../include
rm -rf asm-$2
rm -f asm
mkdir asm-$2
ln -s asm-$2 asm
else
cd ./include
rm -f asm
ln -s asm-$2 asm
fi
rm -f asm-$2/arch
if [ -z "$6" -o "$6" = "NULL" ] ; then
ln -s ${LNPREFIX}arch-$3 asm-$2/arch
else
ln -s ${LNPREFIX}arch-$6 asm-$2/arch
fi
# create link for s3c24xx SoC
if [ "$3" = "s3c24xx" ] ; then
rm -f regs.h
ln -s $6.h regs.h
rm -f asm-$2/arch
ln -s arch-$3 asm-$2/arch
fi
# create link for s3c64xx SoC
if [ "$3" = "s3c64xx" ] ; then
rm -f regs.h
ln -s $6.h regs.h
rm -f asm-$2/arch
ln -s arch-$3 asm-$2/arch
fi
# create link for s5pc1xx SoC
if [ "$3" = "s5pc1xx" ] ; then
rm -f regs.h
ln -s $6.h regs.h
rm -f asm-$2/arch
ln -s arch-$3 asm-$2/arch
fi
# create link for s5pc11x SoC
if [ "$3" = "s5pc11x" ] ; then
rm -f regs.h
ln -s $6.h regs.h
rm -f asm-$2/arch
ln -s arch-$3 asm-$2/arch
fi
# create link for s5p64xx SoC
if [ "$3" = "s5p64xx" ] ; then
rm -f regs.h
ln -s $6.h regs.h
rm -f asm-$2/arch
ln -s arch-$3 asm-$2/arch
fi
# create link for s5p644x SoC
if [ "$3" = "s5p644x" ] ; then
rm -f regs.h
ln -s $6.h regs.h
rm -f asm-$2/arch
ln -s arch-$3 asm-$2/arch
fi
if [ "$2" = "arm" ] ; then
rm -f asm-$2/proc
ln -s ${LNPREFIX}proc-armv asm-$2/proc
fi
# create link for s3c64xx-mp SoC
if [ "$3" = "s3c64xx-mp" ] ; then
rm -f regs.h
ln -s $6.h regs.h
rm -f asm-$2/arch
ln -s arch-$3 asm-$2/arch
fi
#
# Create include file for Make
#
echo "ARCH = $2" > config.mk
echo "CPU = $3" >> config.mk
echo "BOARD = $4" >> config.mk
[ "$5" ] && [ "$5" != "NULL" ] && echo "VENDOR = $5" >> config.mk
[ "$6" ] && [ "$6" != "NULL" ] && echo "SOC = $6" >> config.mk
#
# Create board specific header file
#
if [ "$APPEND" = "yes" ] # Append to existing config file
then
echo >> config.h
else
> config.h # Create new config file
fi
echo "/* Automatically generated - do not edit */" >>config.h
echo "#include <configs/$1.h>" >>config.h
exit 0- [ "${BOARD_NAME}" ] || BOARD_NAME="$1"：看BOARD_NAME变量是否有值，如果有值就维持不变；如果无值就给他赋值为$1
- 25、26行判断传的参数个数小于4或者大于6，就返回1，所以：mkconfig脚本传参只能是4、5、6。
- 从第33行到第118行，都是在创建符号链接。为什么要创建符号链接？这些符号链接文件的存在就是整个配置过程的核心，这些符号链接文件（文件夹）的主要作用是给头文件包含等过程提供指向性连接。根本目的是让uboot具有可移植性。
- 第一个链接：在include目录下创建asm文件，指向asm-arm。（46-48行），第二个：在inlcude/asm-arm下创建一个arch文件，指向include/asm-arm/arch-s5pc110，第三个：在include目录下创建regs.h文件，指向include/s5pc110.h，然后删除第二个，第四个：在inlcude/asm-arm下创建一个arch文件，指向include/asm-arm/arch-s5pc11x，第五个：在include/asm-arm下创建一个proc文件，指向include/asm-arm/proc-armv。一共创建了4个符号链接。这4个符号链接将来在写代码过程中，头文件包含时非常有用。譬如一个头文件包含可能是：#include <asm/xx.h>
- 123-129行：创建include/config.mk文件，是为了让主Makefile在第133行去包含的。
- 134-141行：创建（默认情况）/追加（make -a时追加）include/config.h文件，x210_sd.h文件会被用来生成一个autoconfig.mk文件，这个文件会被主Makefile引入，指导整个编译过程。这里面的这些宏定义会影响我们对uboot中大部分.c文件中一些条件编译的选择。从而实现最终的可移植性。
以下是 Makefile 代码：
# (C) Copyright 2000-2008
# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
#
# See file CREDITS for list of people who contributed to this
# project.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundatio; either version 2 of
# the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
# MA 02111-1307 USA
#
VERSION = 1
PATCHLEVEL = 3
SUBLEVEL = 4
EXTRAVERSION =
U_BOOT_VERSION = $(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)
VERSION_FILE = $(obj)include/version_autogenerated.h
HOSTARCH := $(shell uname -m |
sed -e s/i.86/i386/
-e s/sun4u/sparc64/
-e s/arm.*/arm/
-e s/sa110/arm/
-e s/powerpc/ppc/
-e s/ppc64/ppc/
-e s/macppc/ppc/)
HOSTOS := $(shell uname -s | tr '[:upper:]' '[:lower:]' |
sed -e 's/(cygwin).*/cygwin/')
export HOSTARCH HOSTOS
# Deal with colliding definitions from tcsh etc.
VENDOR=
#########################################################################
# Allow for silent builds
ifeq (,$(findstring s,$(MAKEFLAGS)))
XECHO = echo
else
XECHO = :
endif
#########################################################################
#
# U-boot build supports producing a object files to the separate external
# directory. Two use cases are supported:
#
# 1) Add O= to the make command line
# 'make O=/tmp/build all'
#
# 2) Set environement variable BUILD_DIR to point to the desired location
# 'export BUILD_DIR=/tmp/build'
# 'make'
#
# The second approach can also be used with a MAKEALL script
# 'export BUILD_DIR=/tmp/build'
# './MAKEALL'
#
# Command line 'O=' setting overrides BUILD_DIR environent variable.
#
# When none of the above methods is used the local build is performed and
# the object files are placed in the source directory.
#
ifdef O
ifeq ("$(origin O)", "command line")
BUILD_DIR := $(O)
endif
endif
ifneq ($(BUILD_DIR),)
saved-output := $(BUILD_DIR)
# Attempt to create a output directory.
$(shell [ -d ${BUILD_DIR} ] || mkdir -p ${BUILD_DIR})
# Verify if it was successful.
BUILD_DIR := $(shell cd $(BUILD_DIR) && /bin/pwd)
$(if $(BUILD_DIR),,$(error output directory "$(saved-output)" does not exist))
endif # ifneq ($(BUILD_DIR),)
OBJTREE := $(if $(BUILD_DIR),$(BUILD_DIR),$(CURDIR))
SRCTREE := $(CURDIR)
TOPDIR := $(SRCTREE)
LNDIR := $(OBJTREE)
export TOPDIR SRCTREE OBJTREE
MKCONFIG := $(SRCTREE)/mkconfig
export MKCONFIG
ifneq ($(OBJTREE),$(SRCTREE))
REMOTE_BUILD := 1
export REMOTE_BUILD
endif
# $(obj) and (src) are defined in config.mk but here in main Makefile
# we also need them before config.mk is included which is the case for
# some targets like unconfig, clean, clobber, distclean, etc.
ifneq ($(OBJTREE),$(SRCTREE))
obj := $(OBJTREE)/
src := $(SRCTREE)/
else
obj :=
src :=
endif
export obj src
# Make sure CDPATH settings don't interfere
unexport CDPATH
#########################################################################
ifeq ($(ARCH),powerpc)
ARCH = ppc
endif
ifeq ($(obj)include/config.mk,$(wildcard $(obj)include/config.mk))
# load ARCH, BOARD, and CPU configuration
include $(obj)include/config.mk
export ARCH CPU BOARD VENDOR SOC
ifndef CROSS_COMPILE
ifeq ($(HOSTARCH),$(ARCH))
CROSS_COMPILE =
else
ifeq ($(ARCH),ppc)
CROSS_COMPILE = ppc_8xx-
endif
ifeq ($(ARCH),arm)
#CROSS_COMPILE = arm-linux-
#CROSS_COMPILE = /usr/local/arm/4.4.1-eabi-cortex-a8/usr/bin/arm-linux-
#CROSS_COMPILE = /usr/local/arm/4.2.2-eabi/usr/bin/arm-linux-
CROSS_COMPILE = /usr/local/arm/arm-2009q3/bin/arm-none-linux-gnueabi-
endif
ifeq ($(ARCH),i386)
CROSS_COMPILE = i386-linux-
endif
ifeq ($(ARCH),mips)
CROSS_COMPILE = mips_4KC-
endif
ifeq ($(ARCH),nios)
CROSS_COMPILE = nios-elf-
endif
ifeq ($(ARCH),nios2)
CROSS_COMPILE = nios2-elf-
endif
ifeq ($(ARCH),m68k)
CROSS_COMPILE = m68k-elf-
endif
ifeq ($(ARCH),microblaze)
CROSS_COMPILE = mb-
endif
ifeq ($(ARCH),blackfin)
CROSS_COMPILE = bfin-uclinux-
endif
ifeq ($(ARCH),avr32)
CROSS_COMPILE = avr32-linux-
endif
ifeq ($(ARCH),sh)
CROSS_COMPILE = sh4-linux-
endif
ifeq ($(ARCH),sparc)
CROSS_COMPILE = sparc-elf-
endif # sparc
endif # HOSTARCH,ARCH
endif # CROSS_COMPILE
export CROSS_COMPILE
# load other configuration
include $(TOPDIR)/config.mk
#########################################################################
# U-Boot objects....order is important (i.e. start must be first)
OBJS = cpu/$(CPU)/start.o
ifeq ($(CPU),i386)
OBJS += cpu/$(CPU)/start16.o
OBJS += cpu/$(CPU)/reset.o
endif
ifeq ($(CPU),ppc4xx)
OBJS += cpu/$(CPU)/resetvec.o
endif
ifeq ($(CPU),mpc85xx)
OBJS += cpu/$(CPU)/resetvec.o
endif
OBJS := $(addprefix $(obj),$(OBJS))
LIBS = lib_generic/libgeneric.a
LIBS += $(shell if [ -f board/$(VENDOR)/common/Makefile ]; then echo
"board/$(VENDOR)/common/lib$(VENDOR).a"; fi)
LIBS += cpu/$(CPU)/lib$(CPU).a
ifdef SOC
LIBS += cpu/$(CPU)/$(SOC)/lib$(SOC).a
endif
ifeq ($(CPU),ixp)
LIBS += cpu/ixp/npe/libnpe.a
endif
LIBS += lib_$(ARCH)/lib$(ARCH).a
LIBS += fs/cramfs/libcramfs.a fs/fat/libfat.a fs/fdos/libfdos.a fs/jffs2/libjffs2.a
fs/reiserfs/libreiserfs.a fs/ext2/libext2fs.a
LIBS += net/libnet.a
LIBS += disk/libdisk.a
LIBS += drivers/bios_emulator/libatibiosemu.a
LIBS += drivers/block/libblock.a
LIBS += drivers/dma/libdma.a
LIBS += drivers/hwmon/libhwmon.a
LIBS += drivers/i2c/libi2c.a
LIBS += drivers/input/libinput.a
LIBS += drivers/misc/libmisc.a
LIBS += drivers/mmc/libmmc.a
LIBS += drivers/mtd/libmtd.a
LIBS += drivers/mtd/nand/libnand.a
LIBS += drivers/mtd/nand_legacy/libnand_legacy.a
LIBS += drivers/mtd/onenand/libonenand.a
LIBS += drivers/mtd/ubi/libubi.a
LIBS += drivers/mtd/spi/libspi_flash.a
LIBS += drivers/net/libnet.a
LIBS += drivers/net/sk98lin/libsk98lin.a
LIBS += drivers/pci/libpci.a
LIBS += drivers/pcmcia/libpcmcia.a
LIBS += drivers/spi/libspi.a
ifeq ($(CPU),mpc83xx)
LIBS += drivers/qe/qe.a
endif
ifeq ($(CPU),mpc85xx)
LIBS += drivers/qe/qe.a
endif
LIBS += drivers/rtc/librtc.a
LIBS += drivers/serial/libserial.a
LIBS += drivers/usb/libusb.a
LIBS += drivers/video/libvideo.a
LIBS += common/libcommon.a
LIBS += libfdt/libfdt.a
LIBS += api/libapi.a
LIBS += post/libpost.a
LIBS := $(addprefix $(obj),$(LIBS))
.PHONY : $(LIBS) $(VERSION_FILE)
LIBBOARD = board/$(BOARDDIR)/lib$(BOARD).a
LIBBOARD := $(addprefix $(obj),$(LIBBOARD))
# Add GCC lib
PLATFORM_LIBS += -L $(shell dirname `$(CC) $(CFLAGS) -print-libgcc-file-name`) -lgcc
# The "tools" are needed early, so put this first
# Don't include stuff already done in $(LIBS)
SUBDIRS = tools
examples
api_examples
.PHONY : $(SUBDIRS)
ifeq ($(CONFIG_NAND_U_BOOT),y)
NAND_SPL = nand_spl
U_BOOT_NAND = $(obj)u-boot-nand.bin
endif
ifeq ($(CONFIG_ONENAND_U_BOOT),y)
ONENAND_IPL = onenand_bl1
U_BOOT_ONENAND = $(obj)u-boot-onenand.bin
endif
__OBJS := $(subst $(obj),,$(OBJS))
__LIBS := $(subst $(obj),,$(LIBS)) $(subst $(obj),,$(LIBBOARD))
#########################################################################
#########################################################################
ALL += $(obj)u-boot.srec $(obj)u-boot.bin $(obj)System.map $(U_BOOT_NAND) $(U_BOOT_ONENAND) $(obj)u-boot.dis
ifeq ($(ARCH),blackfin)
ALL += $(obj)u-boot.ldr
endif
all: $(ALL)
$(obj)u-boot.hex: $(obj)u-boot
$(OBJCOPY) ${OBJCFLAGS} -O ihex $< $@
$(obj)u-boot.srec: $(obj)u-boot
$(OBJCOPY) ${OBJCFLAGS} -O srec $< $@
$(obj)u-boot.bin: $(obj)u-boot
$(OBJCOPY) ${OBJCFLAGS} -O binary $< $@
$(obj)u-boot.ldr: $(obj)u-boot
$(LDR) -T $(CONFIG_BFIN_CPU) -f -c $@ $< $(LDR_FLAGS)
$(obj)u-boot.ldr.hex: $(obj)u-boot.ldr
$(OBJCOPY) ${OBJCFLAGS} -O ihex $< $@ -I binary
$(obj)u-boot.ldr.srec: $(obj)u-boot.ldr
$(OBJCOPY) ${OBJCFLAGS} -O srec $< $@ -I binary
$(obj)u-boot.img: $(obj)u-boot.bin
./tools/mkimage -A $(ARCH) -T firmware -C none
-a $(TEXT_BASE) -e 0
-n $(shell sed -n -e 's/.*U_BOOT_VERSION//p' $(VERSION_FILE) |
sed -e 's/"[ ]*$$/ for $(BOARD) board"/')
-d $< $@
$(obj)u-boot.sha1: $(obj)u-boot.bin
$(obj)tools/ubsha1 $(obj)u-boot.bin
$(obj)u-boot.dis: $(obj)u-boot
$(OBJDUMP) -d $< > $@
$(obj)u-boot: depend $(SUBDIRS) $(OBJS) $(LIBBOARD) $(LIBS) $(LDSCRIPT)
UNDEF_SYM=`$(OBJDUMP) -x $(LIBBOARD) $(LIBS) |
sed -n -e 's/.*($(SYM_PREFIX)__u_boot_cmd_.*)/-u1/p'|sort|uniq`;
cd $(LNDIR) && $(LD) $(LDFLAGS) $$UNDEF_SYM $(__OBJS)
--start-group $(__LIBS) --end-group $(PLATFORM_LIBS)
-Map u-boot.map -o u-boot
$(OBJS): depend $(obj)include/autoconf.mk
$(MAKE) -C cpu/$(CPU) $(if $(REMOTE_BUILD),$@,$(notdir $@))
$(LIBS): depend $(obj)include/autoconf.mk
$(MAKE) -C $(dir $(subst $(obj),,$@))
$(LIBBOARD): depend $(LIBS) $(obj)include/autoconf.mk
$(MAKE) -C $(dir $(subst $(obj),,$@))
$(SUBDIRS): depend $(obj)include/autoconf.mk
$(MAKE) -C $@ all
$(LDSCRIPT): depend $(obj)include/autoconf.mk
$(MAKE) -C $(dir $@) $(notdir $@)
$(NAND_SPL): $(VERSION_FILE) $(obj)include/autoconf.mk
$(MAKE) -C nand_spl/board/$(BOARDDIR) all
$(U_BOOT_NAND): $(NAND_SPL) $(obj)u-boot.bin $(obj)include/autoconf.mk
cat $(obj)nand_spl/u-boot-spl-16k.bin $(obj)u-boot.bin > $(obj)u-boot-nand.bin
#$(ONENAND_IPL): $(VERSION_FILE) $(obj)include/autoconf.mk
# $(MAKE) -C onenand_ipl/board/$(BOARDDIR) all
#
#$(U_BOOT_ONENAND): $(ONENAND_IPL) $(obj)u-boot.bin $(obj)include/autoconf.mk
# cat $(obj)onenand_ipl/onenand-ipl-2k.bin $(obj)u-boot.bin > $(obj)u-boot-onenand.bin
# cat $(obj)onenand_ipl/onenand-ipl-4k.bin $(obj)u-boot.bin > $(obj)u-boot-flexonenand.bin
$(ONENAND_IPL): $(VERSION_FILE) $(obj)include/autoconf.mk
$(MAKE) -C $(obj)onenand_bl1/$(BOARD) all
$(U_BOOT_ONENAND): $(ONENAND_IPL) $(obj)u-boot.bin $(obj)include/autoconf.mk
cat $(obj)onenand_bl1/$(BOARD)/BL1.bin.padding $(obj)u-boot.bin > $(U_BOOT_ONENAND)
$(VERSION_FILE):
@( printf '#define U_BOOT_VERSION "U-Boot %s%s"n' "$(U_BOOT_VERSION)"
'$(shell $(CONFIG_SHELL) $(TOPDIR)/tools/setlocalversion $(TOPDIR))'
) > $@.tmp
@cmp -s $@ $@.tmp && rm -f $@.tmp || mv -f $@.tmp $@
gdbtools:
$(MAKE) -C tools/gdb all || exit 1
updater:
$(MAKE) -C tools/updater all || exit 1
env:
$(MAKE) -C tools/env all MTD_VERSION=${MTD_VERSION} || exit 1
depend dep: $(VERSION_FILE)
for dir in $(SUBDIRS) ; do $(MAKE) -C $$dir _depend ; done
TAG_SUBDIRS += include
TAG_SUBDIRS += lib_generic board/$(BOARDDIR)
TAG_SUBDIRS += cpu/$(CPU)
TAG_SUBDIRS += lib_$(ARCH)
TAG_SUBDIRS += fs/cramfs
TAG_SUBDIRS += fs/fat
TAG_SUBDIRS += fs/fdos
TAG_SUBDIRS += fs/jffs2
TAG_SUBDIRS += net
TAG_SUBDIRS += disk
TAG_SUBDIRS += common
TAG_SUBDIRS += drivers/bios_emulator
TAG_SUBDIRS += drivers/block
TAG_SUBDIRS += drivers/hwmon
TAG_SUBDIRS += drivers/i2c
TAG_SUBDIRS += drivers/input
TAG_SUBDIRS += drivers/misc
TAG_SUBDIRS += drivers/mmc
TAG_SUBDIRS += drivers/mtd
TAG_SUBDIRS += drivers/mtd/nand
TAG_SUBDIRS += drivers/mtd/nand_legacy
TAG_SUBDIRS += drivers/mtd/onenand
TAG_SUBDIRS += drivers/mtd/spi
TAG_SUBDIRS += drivers/net
TAG_SUBDIRS += drivers/net/sk98lin
TAG_SUBDIRS += drivers/pci
TAG_SUBDIRS += drivers/pcmcia
TAG_SUBDIRS += drivers/qe
TAG_SUBDIRS += drivers/rtc
TAG_SUBDIRS += drivers/serial
TAG_SUBDIRS += drivers/spi
TAG_SUBDIRS += drivers/usb
TAG_SUBDIRS += drivers/video
tags ctags:
ctags -w -o $(obj)ctags `find $(SUBDIRS) $(TAG_SUBDIRS)
-name '*.[ch]' -print`
etags:
etags -a -o $(obj)etags `find $(SUBDIRS) $(TAG_SUBDIRS)
-name '*.[ch]' -print`
cscope:
find $(SUBDIRS) $(TAG_SUBDIRS) -name '*.[ch]' -print
> cscope.files
cscope -b -q -k
$(obj)System.map: $(obj)u-boot
@$(NM) $< |
grep -v '(compiled)|(.o$$)|( [aUw] )|(..ng$$)|(LASH[RL]DI)' |
sort > $(obj)System.map
#
# Auto-generate the autoconf.mk file (which is included by all makefiles)
#
# This target actually generates 2 files; autoconf.mk and autoconf.mk.dep.
# the dep file is only include in this top level makefile to determine when
# to regenerate the autoconf.mk file.
$(obj)include/autoconf.mk.dep: $(obj)include/config.h include/common.h
@$(XECHO) Generating $@ ;
set -e ;
: Generate the dependancies ;
$(CC) -x c -DDO_DEPS_ONLY -M $(HOST_CFLAGS) $(CPPFLAGS)
-MQ $(obj)include/autoconf.mk include/common.h > $@
$(obj)include/autoconf.mk: $(obj)include/config.h
@$(XECHO) Generating $@ ;
set -e ;
: Extract the config macros ;
$(CPP) $(CFLAGS) -DDO_DEPS_ONLY -dM include/common.h |
sed -n -f tools/scripts/define2mk.sed > $@
sinclude $(obj)include/autoconf.mk.dep
#########################################################################
else # !config.mk
all $(obj)u-boot.hex $(obj)u-boot.srec $(obj)u-boot.bin
$(obj)u-boot.img $(obj)u-boot.dis $(obj)u-boot
$(SUBDIRS) $(VERSION_FILE) gdbtools updater env depend
dep tags ctags etags cscope $(obj)System.map:
@echo "System not configured - see README" >&2
@ exit 1
endif # config.mk
.PHONY : CHANGELOG
CHANGELOG:
git log --no-merges U-Boot-1_1_5.. |
unexpand -a | sed -e 's/ss*$$//' > $@
#########################################################################
unconfig:
@rm -f $(obj)include/config.h $(obj)include/config.mk
$(obj)board/*/config.tmp $(obj)board/*/*/config.tmp
$(obj)include/autoconf.mk $(obj)include/autoconf.mk.dep
$(obj)board/$(VENDOR)/$(BOARD)/config.mk
#========================================================================
# PowerPC
#========================================================================
x210_sd_config : unconfig
@$(MKCONFIG) $(@:_config=) arm s5pc11x x210 samsung s5pc110
@echo "TEXT_BASE = 0xc3e00000" > $(obj)board/samsung/x210/config.mk
clean:
@rm -f $(obj)examples/82559_eeprom $(obj)examples/eepro100_eeprom
$(obj)examples/hello_world $(obj)examples/interrupt
$(obj)examples/mem_to_mem_idma2intr
$(obj)examples/sched $(obj)examples/smc91111_eeprom
$(obj)examples/test_burst $(obj)examples/timer
@rm -f $(obj)tools/bmp_logo $(obj)tools/easylogo/easylogo
$(obj)tools/env/{fw_printenv,fw_setenv}
$(obj)tools/envcrc
$(obj)tools/gdb/{astest,gdbcont,gdbsend}
$(obj)tools/gen_eth_addr $(obj)tools/img2srec
$(obj)tools/mkimage $(obj)tools/mpc86x_clk
$(obj)tools/ncb $(obj)tools/ubsha1
@rm -f $(obj)board/cray/L1/{bootscript.c,bootscript.image}
$(obj)board/netstar/{eeprom,crcek,crcit,*.srec,*.bin}
$(obj)board/trab/trab_fkt $(obj)board/voiceblue/eeprom
$(obj)board/{integratorap,integratorcp}/u-boot.lds
$(obj)board/{bf533-ezkit,bf533-stamp,bf537-stamp,bf561-ezkit}/u-boot.lds
$(obj)cpu/blackfin/bootrom-asm-offsets.[chs]
@rm -f $(obj)include/bmp_logo.h
@rm -f $(obj)nand_spl/{u-boot-spl,u-boot-spl.map,System.map}
@rm -f $(obj)onenand_ipl/onenand-{ipl,ipl.bin,ipl-2k.bin,ipl-4k.bin,ipl.map}
@rm -f $(obj)api_examples/demo $(VERSION_FILE)
@find $(OBJTREE) -type f
( -name 'core' -o -name '*.bak' -o -name '*~'
-o -name '*.o' -o -name '*.a' ) -print
| xargs rm -f
clobber: clean
@find $(OBJTREE) -type f ( -name .depend
-o -name '*.srec' -o -name '*.bin' -o -name u-boot.img )
-print0
| xargs -0 rm -f
@rm -f $(OBJS) $(obj)*.bak $(obj)ctags $(obj)etags $(obj)TAGS
$(obj)cscope.* $(obj)*.*~
@rm -f $(obj)u-boot $(obj)u-boot.map $(obj)u-boot.hex $(ALL)
@rm -f $(obj)tools/{crc32.c,environment.c,env/crc32.c,md5.c,sha1.c,inca-swap-bytes}
@rm -f $(obj)tools/{image.c,fdt.c,fdt_ro.c,fdt_rw.c,fdt_strerror.c,zlib.h}
@rm -f $(obj)tools/{fdt_wip.c,libfdt_internal.h}
@rm -f $(obj)cpu/mpc824x/bedbug_603e.c
@rm -f $(obj)include/asm/proc $(obj)include/asm/arch $(obj)include/asm
@rm -f $(obj)include/regs.h
@[ ! -d $(obj)nand_spl ] || find $(obj)nand_spl -lname "*" -print | xargs rm -f
@[ ! -d $(obj)onenand_ipl ] || find $(obj)onenand_ipl -lname "*" -print | xargs rm -f
@[ ! -d $(obj)api_examples ] || find $(obj)api_examples -lname "*" -print | xargs rm -f
ifeq ($(OBJTREE),$(SRCTREE))
mrproper
distclean: clobber unconfig
else
mrproper
distclean: clobber unconfig
rm -rf $(obj)*
endif
backup:
F=`basename $(TOPDIR)` ; cd .. ;
gtar --force-local -zcvf `date "+$$F-%Y-%m-%d-%T.tar.gz"` $$F
#########################################################################
最后
以上就是不安芒果为你收集整理的深入浅析Linux下uboot之（三）-----------------------：Makefile分析的全部内容，希望文章能够帮你解决深入浅析Linux下uboot之（三）-----------------------：Makefile分析所遇到的程序开发问题。
如果觉得靠谱客网站的内容还不错，欢迎将靠谱客网站推荐给程序员好友。
本图文内容来源于网友提供，作为学习参考使用，或来自网络收集整理，版权属于原作者所有。
发表评论 取消回复