u-boot2013.01 sdmk2410 配置和编译过程分析

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1.jz2440移植新u-boot，带有设备树 kernel 准备资料
分析自带的smdk2410 的配置过程
2. u-boot2013.01 版本的
3. 编译
3.1 boards.cfg 有smdk2410 的配置
3.2 make smdk2410_config
   Configuring for smdk2410 board...
3.3 make

4.概述分析
4.1 在顶级目录下的boards.cfg中包含了大多数的板级配置文件
基本信息如下。例如smdk2410的配置信息
# Target                     ARCH        CPU         Board name          Vendor            SoC         Options
smdk2410                     arm         arm920t     -                   samsung        s3c24x0

boards.cfg 从 uboot2010.09 开始出现
4.2 这个编译的过程需要先配置，后编译。
       配置执行make sdmk2410_config 文件
       随后make
5 分析配置过程

5.1 顶层目录 README 下 For all supported boards there are ready-to-use default 指明了如何进行编译
顶层目录下的Makefile中并没有smdk2410_config 文件，取而带之的是 %_config ，%代表着任意字符
   make smdk2410_config 会执行
       会在makefile 文件中找到
   %_config::   unconfig
   @$(MKCONFIG) -A $(@:_config=)

   分析参考链接： http://blog.chinaunix.net/uid-18921523-id-165029.html

      %_config::   unconfig
5.1.1
    %代表着任意字符   unconfig 前边有双 :: 这就是Makefile中的双引号规则
      Makefile 中规定：一个目标可以出现在多个规则中。但是这些规则必须是同一类型的规则，要么都是普通规则，要么都是双冒号规则。
      而不允许一个目标同时出现在两种不同类型的规则中。双冒号规则和普通规则的处理的不同点表现在以下几个方面：
   1. 双冒号规则中，当依赖文件比目标更新时。规则将会被执行。对于一个没有依赖而只有命令行的双冒号规则，
   当引用此目标时，规则的命令将会被无条件执行。
   而普通规则，当规则的目标文件存在时，此规则的命令永远不会被执行（目标文件永远是最新的）。
   2 .当同一个文件作为多个双冒号规则的目标时。这些不同的规则会被独立的处理，而不是像普通规则那样合并所有的依赖到一个目标文件。
   这就意味着对这些规则的处理就像多个不同的普通规则一样。就是说多个双冒号规则中的每一个的依赖文件被改变之后，
   make只执行此规则定义的命令，而其它的以这个文件作为目标的双冒号规则将不会被执行。

       unconfig 也是一个也是一个目标
       即

        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

     故先删除一些文件
   5.1.2
      @$(MKCONFIG) -A $(@:_config=)
      第一个@ 表示的功能是取消回显
      $(MKCONFIG) 表示取MKCONFIG的内容
      搜索得到
      SRCTREE       := $(CURDIR)
      MKCONFIG   := $(SRCTREE)/mkconfig
       export MKCONFIG
       即： MKCONFIG 就是当前目录下的mkconfig 文件
       @:_config=
       @ 表示目标即%_config ,也就是 smdk2410_config
       :_config= 表示将_config= 赋值为空，从而得到了
       smdk2410

          @$(MKCONFIG) -A $(@:_config=)
       ==> mkconfig -A smdk2410

   执行mkconfig 的配置过程
6 执行mkconfig 的过程
mkconfig的目的：Script to create header files and links to configure
生成头文件和连接的
6.1 if [ $ $# -eq 2 $ -a $ "$1" = "-A" $ ] ; then
       $# 传给脚本的参数的格式
       判读输入的参数是等于2 ，并且第一个参数是否我 -A 成立则执行

   line=`egrep -i "^[[:space:]]*${2}[[:space:]]" boards.cfg` || {
       echo "make: *** No rule to make target \`$2_config'. Stop." >&2
       exit 1
   }
   egrep -i 一行一行的从boards.cfg中读取数据
   "^[[:space:]]*${2}[[:space:]]"表示第二个参数及 smdk2410的前边没有空格，后边有空格
   ==>
   line = smdk2410       arm         arm920t     -         samsung        s3c24x0
                   $1                       $2                       $3                $4                    $5                           $6

   set ${line}

        while [ $# -gt 0 ] ;   //参数的格式大于0， 则执行 判断$1（smdk2410 是否为 -- -a -n 等。）        case "$1" in        --) shift ; break ;;        -a) shift ; APPEND=yes ;;        -n) shift ; BOARD_NAME="${1%_config}" ; shift ;;        -t) shift ; TARGETS="`echo $1 | sed 's:_: :g'` ${TARGETS}" ; shift ;;        *)  break ;;        esac

   done
   以上语句不执行

   # Strip all options and/or _config suffixes
   CONFIG_NAME="${1%_config}"
====》CONFIG_NAME=smdk2410_config

[ "${BOARD_NAME}" ] || BOARD_NAME="${1%_config}"
[ "${BOARD_NAME}" ] BOARD_NAME没有赋值过，故执行BOARD_NAME="${1%_config}"
==>BOARD_NAME = sdmk2410_config

arch="$2"
cpu=`echo $3 | awk 'BEGIN {FS = ":"} ; {print $1}'`
spl_cpu=`echo $3 | awk 'BEGIN {FS = ":"} ; {print $2}'`

==> arch = arm
       cpu = arm920t
       spl_cpu = arm920t

       awk 参考连接   http://www.cnblogs.com/emanlee/p/3327576.html

 if [ "$4" = "-" ] ; then    board=${BOARD_NAME}else    board="$4"fi        ==> $4 为  board = smdk2410    [ $# -gt 4 ] && [ "$5" != "-" ] && vendor="$5"[ $# -gt 5 ] && [ "$6" != "-" ] && soc="$6"[ $# -gt 6 ] && [ "$7" != "-" ] && {==》vendor  = samsung        soc      = s3c24x0

if [ "${ARCH}" -a "${ARCH}" != "${arch}" ]; then    echo "Failed: \$ARCH=${ARCH}, should be '${arch}' for ${BOARD_NAME}" 1>&2    exit 1fi

以上不执行

if [ "$options" ] ; then    echo "Configuring for ${BOARD_NAME} - Board: ${CONFIG_NAME}, Options: ${options}"else    echo "Configuring for ${BOARD_NAME} board..."fi

执行 echo "Configuring for ${BOARD_NAME} board..."

#
# Create link to architecture specific headers
#
执行

    cd ./include    rm -f asm    ln -s ../arch/${arch}/include/asm asm

   创建软连接
   当前所在的目录 include目录
   ls -s ../arm/arm/include/asm asm
   将 ../arm/arm/include/asm 文件在 include 目录下创建一个软连接 asm
   ==>lrwxrwxrwx 1 gus gus 23 Jul 11 18:49 asm -> ../arch/arm/include/asm

    rm -f asm/arch    if [ -z "${soc}" ] ; then    ln -s ${LNPREFIX}arch-${cpu} asm/archelse    ln -s ${LNPREFIX}arch-${soc} asm/archfi

if判断中-z用法判断字符串是否有值，有值返回0
执行    ln -s ${LNPREFIX}arch-${soc} asm/arch
==》 ln -s arch-s3c24x0 asm/arch
   lrwxrwxrwx 1 gus gus 12 Jul 11 18:49 asm/arch -> arch-s3c24x0

if [ "${arch}" = "arm" ] ; then    rm -f asm/proc    ln -s ${LNPREFIX}proc-armv asm/procfi

ln -s ${LNPREFIX}proc-armv proc-armv
==》 ln -s proc-armv proc-armv
lrwxrwxrwx 1 gus gus 9 Jul 11 18:49 asm/proc -> proc-armv

 ## Create include file for Make# echo "ARCH   = ${arch}"    if [ ! -z "$spl_cpu" ] ; then    echo 'ifeq ($(CONFIG_SPL_BUILD),y)'    echo "CPU    = ${spl_cpu}"    echo "else"    echo "CPU    = ${cpu}"    echo "endif"    else    echo "CPU    = ${cpu}"    fi    echo "BOARD  = ${board}"     [ "${vendor}" ] && echo "VENDOR = ${vendor}"    [ "${soc}"    ] && echo "SOC    = ${soc}"    exit 0 ) > config.mk

==>config.mk 的内容

     ARCH = arm     CPU = arn920t     BOARD = smdk2410    VENDOR = samsung    SOC = s3c24x0.

    # Assign board directory to BOARDIR variableif [ -z "${vendor}" ] ; then    BOARDDIR=${board}else    BOARDDIR=${vendor}/${board}fi

==> BOARDDIR=${vendor}/${board}

#if [ "$APPEND" = "yes" ]    # Append to existing config filethen    echo >> config.helse    > config.h        # Create new config filefi

==》 > config.h # Create new config file

echo "/* Automatically generated - do not edit */" >>config.hecho "#define CONFIG_SYS_ARCH  \"${arch}\""  >> config.hecho "#define CONFIG_SYS_CPU   \"${cpu}\""   >> config.hecho "#define CONFIG_SYS_BOARD \"${board}\"" >> config.h==>#define CONFIG_SYS_ARCH           "arm"    #define CONFIG_SYS_CPU               "arm920t"    #define CONFIG_SYS_BOARD            "smdk2410"

        [ "${vendor}" ] && echo "#define CONFIG_SYS_VENDOR \"${vendor}\"" >> config.h[ "${soc}"    ] && echo "#define CONFIG_SYS_SOC    \"${soc}\""    >> config.h

==》

#define CONFIG_SYS_VENDOR  samsung #define CONFIG_SYS_SOC    s3c24x0

#define CONFIG_BOARDDIR board/$BOARDDIR#include <config_cmd_defaults.h>#include <config_defaults.h>#include <configs/${CONFIG_NAME}.h>#include <asm/config.h>#include <config_fallbacks.h>#include <config_uncmd_spl.h>

==》 #define CONFIG_BOARDDIR board/samsung/smdk2410

config.h

/* Automatically generated - do not edit */#define CONFIG_SYS_ARCH  "arm"#define CONFIG_SYS_CPU   "arm920t"#define CONFIG_SYS_BOARD "smdk2410"#define CONFIG_SYS_VENDOR "samsung"#define CONFIG_SYS_SOC    "s3c24x0"#define CONFIG_BOARDDIR board/samsung/smdk2410#include <config_cmd_defaults.h>#include <config_defaults.h>#include <configs/smdk2410.h>#include <asm/config.h>#include <config_fallbacks.h>#include <config_uncmd_spl.h>

==================================================编译过程=================================================================
参考连接：http://www.cnblogs.com/heaad/archive/2010/07/17/1779806.html
7.编译过程
7.1 若没有执行 make <board_name>_config 则出现 System not configured - see README
7.2 配置过程的文件和编译过程怎么关联在一起

# load ARCH, BOARD, and CPU configurationinclude $(obj)include/config.mkexport    ARCH CPU BOARD VENDOR SOC

导出了 config.mk 中的 ARCH CPU BOARD VENDOR SOC

# load other configurationinclude $(TOPDIR)/config.mk

将顶层目录的 config.mk导入 Makefile
其中包括了
CPUDIR=arch/$(ARCH)/cpu/$(CPU)
==> CPUDIR =arch/arm/cpu/arm920t
7.3 make
执行的
all: $(ALL-y) $(SUBDIR_EXAMPLES)
$(ALL-y)的具体内容

# Always append ALL so that arch config.mk's can add custom onesALL-y += $(obj)u-boot.srec $(obj)u-boot.bin $(obj)System.map

u-boot.bin

$(obj)u-boot.bin:    $(obj)u-boot        $(OBJCOPY) ${OBJCFLAGS} -O binary $< $@        $(BOARD_SIZE_CHECK)

目标：u-boot.bin 依赖u-boot
命令$(OBJCOPY) ${OBJCFLAGS} -O binary $< $@
$(BOARD_SIZE_CHECK)

依赖u-boot

$(obj)u-boot:    depend \        $(SUBDIR_TOOLS) $(OBJS) $(LIBBOARD) $(LIBS) $(LDSCRIPT) $(obj)u-boot.lds        $(GEN_UBOOT)

       u-boot 依赖 $(SUBDIR_TOOLS) $(OBJS) $(LIBBOARD) $(LIBS) $(LDSCRIPT) $(obj)u-boot.lds
       命令 $(GEN_UBOOT)

$(SUBDIR_TOOLS)
SUBDIR_TOOLS = tools
$(OBJS)

# U-Boot objects....order is important (i.e. start must be first)OBJS  = $(CPUDIR)/start.o                                                                                    ifeq ($(CPU),x86)RESET_OBJS-$(CONFIG_X86_NO_RESET_VECTOR) += $(CPUDIR)/start16.oRESET_OBJS-$(CONFIG_X86_NO_RESET_VECTOR) += $(CPUDIR)/resetvec.oendififeq ($(CPU),ppc4xx)OBJS += $(CPUDIR)/resetvec.oendififeq ($(CPU),mpc85xx)OBJS += $(CPUDIR)/resetvec.oendif

OBJS := $(addprefix $(obj),$(OBJS) $(RESET_OBJS-))

==》
OBJS = $(CPUDIR)/start.o ==arch/arm/cpu/arm920t/start.o ==>首先被执行的文件

-------------------------------------------------------------------------
OBJS := $(addprefix $(obj),$(OBJS) $(RESET_OBJS-))

$(addprefix <prefix>,<names...>)
名称：加前缀函数——addprefix。
功能：把前缀<prefix>加到<names>中的每个单词后面。
返回：返回加过前缀的文件名序列。
示例：$(addprefix src/,foo bar)返回值是“src/foo src/bar”。
$(obj) = 空
$(OBJS) = arch/arm/cpu/arm920t/start.o
$(RESET_OBJS-) 也为空
==》OBJS :=arch/arm/cpu/arm920t/start.o

GEN_UBOOT 对应的信息

GEN_UBOOT = \        UNDEF_LST=`$(OBJDUMP) -x $(LIBBOARD) $(LIBS) | \        sed  -n -e 's/.*\($(SYM_PREFIX)_u_boot_list_.*\)/-u\1/p'|sort|uniq`;\        cd $(LNDIR) && $(LD) $(LDFLAGS) $(LDFLAGS_$(@F)) \            $$UNDEF_LST $(__OBJS) \            --start-group $(__LIBS) --end-group $(PLATFORM_LIBS) \            -Map u-boot.map -o u-boot

$(@F 查看自动化变量 LDFLAGS_u-boot
怎么得到的这个 LDFLAGS_u-boot
分析： GEN_UBOOT 这个变量下的代码会在
依赖u-boot
$(obj)u-boot:   depend \
       $(SUBDIR_TOOLS) $(OBJS) $(LIBBOARD) $(LIBS) $(LDSCRIPT) $(obj)u-boot.lds
       $(GEN_UBOOT)
   处进行展开
   此处的$@ 表示的是u-boot
   $(@F) 表示什么呢? 其实就是 u-boot
   从而得到 LDFLAGS_u-boot
   LDFLAGS_u-boot 这个变量在哪里定义的和具体的值是什么呢？
   LDFLAGS_u-boot 在顶层目录下的config.mk 中进行定义的

 LDFLAGS_FINAL += -BstaticLDFLAGS_u-boot += -T $(obj)u-boot.lds $(LDFLAGS_FINAL)

    ==》 LDFLAGS_u-boot += -T u-boot.lds -Bstatic

    在加上

     ifneq ($(CONFIG_SYS_TEXT_BASE),)LDFLAGS_u-boot += -Ttext $(CONFIG_SYS_TEXT_BASE)

CONFIG_SYS_TEXT_BASE 没有定义应当为空
==》 LDFLAGS_u-boot = -T u-boot.lds -Bstatic Ttext 0x00

$(__OBJS) 怎么解读:
==》 __OBJS := $(subst $(obj),,$(OBJS))

$(subst <from>,<to>,<text>)
名称：字符串替换函数——subst。
功能：把字串<text>中的<from>字符串替换成<to>。
返回：函数返回被替换过后的字符串。
前边已经推导出：
$(obj) = 空
$(OBJS) = arch/arm/cpu/arm920t/start.o
==》__OBJS = arch/arm/cpu/arm920t/start.o

======================================

8 u-boot 连接时候的信息

UNDEF_LST=`arm-linux-objdump -x board/samsung/smdk2410/libsmdk2410.oapi/libapi.oarch/arm/cpu/arm920t/libarm920t.oarch/arm/cpu/arm920t/s3c24x0/libs3c24x0.oarch/arm/lib/libarm.oboard/samsung/common/libsamsung.ocommon/libcommon.odisk/libdisk.odrivers/bios_emulator/libatibiosemu.odrivers/block/libblock.odrivers/dfu/libdfu.odrivers/dma/libdma.odrivers/fpga/libfpga.odrivers/gpio/libgpio.odrivers/hwmon/libhwmon.odrivers/i2c/libi2c.odrivers/input/libinput.odrivers/misc/libmisc.odrivers/mmc/libmmc.odrivers/mtd/libmtd.odrivers/mtd/nand/libnand.odrivers/mtd/onenand/libonenand.odrivers/mtd/spi/libspi_flash.odrivers/mtd/ubi/libubi.odrivers/net/libnet.odrivers/net/phy/libphy.odrivers/pci/libpci.odrivers/pcmcia/libpcmcia.odrivers/power/battery/libbattery.odrivers/power/fuel_gauge/libfuel_gauge.odrivers/power/libpower.odrivers/power/pmic/libpmic.odrivers/rtc/librtc.odrivers/serial/libserial.odrivers/sound/libsound.odrivers/spi/libspi.odrivers/twserial/libtws.odrivers/usb/eth/libusb_eth.odrivers/usb/gadget/libusb_gadget.odrivers/usb/host/libusb_host.odrivers/usb/musb-new/libusb_musb-new.odrivers/usb/musb/libusb_musb.odrivers/usb/phy/libusb_phy.odrivers/usb/ulpi/libusb_ulpi.odrivers/video/libvideo.odrivers/watchdog/libwatchdog.ofs/cbfs/libcbfs.o fs/cramfs/libcramfs.ofs/ext4/libext4fs.ofs/fat/libfat.ofs/fdos/libfdos.ofs/jffs2/libjffs2.ofs/libfs.ofs/reiserfs/libreiserfs.ofs/ubifs/libubifs.ofs/yaffs2/libyaffs2.ofs/zfs/libzfs.olib/libfdt/libfdt.olib/libgeneric.olib/lzma/liblzma.olib/lzo/liblzo.olib/zlib/libz.onet/libnet.opost/libpost.otest/libtest.o

| sed -n -e 's/.*$_u_boot_list_.*$/-u\1/p'|sort|uniq`;
=======================================================
链接脚本u-boot.lds 决定下边的排列顺序最先排放的是 arch/arm/cpu/arm920t/start.o
=========================================================

cd /home/gus/jz2440/system/u-boot-2013.01-20160711-2440&& arm-linux-ld.bfd  -pie -T u-boot.lds -Bstatic -Ttext 0x0 $UNDEF_LSTarch/arm/cpu/arm920t/start.o--start-groupapi/libapi.oarch/arm/cpu/arm920t/libarm920t.oarch/arm/cpu/arm920t/s3c24x0/libs3c24x0.oarch/arm/lib/libarm.oboard/samsung/common/libsamsung.ocommon/libcommon.odisk/libdisk.odrivers/bios_emulator/libatibiosemu.odrivers/block/libblock.odrivers/dfu/libdfu.odrivers/dma/libdma.odrivers/fpga/libfpga.odrivers/gpio/libgpio.odrivers/hwmon/libhwmon.odrivers/i2c/libi2c.odrivers/input/libinput.odrivers/misc/libmisc.odrivers/mmc/libmmc.odrivers/mtd/libmtd.odrivers/mtd/nand/libnand.odrivers/mtd/onenand/libonenand.odrivers/mtd/spi/libspi_flash.odrivers/mtd/ubi/libubi.odrivers/net/libnet.odrivers/net/phy/libphy.odrivers/pci/libpci.odrivers/pcmcia/libpcmcia.odrivers/power/battery/libbattery.odrivers/power/fuel_gauge/libfuel_gauge.odrivers/power/libpower.odrivers/power/pmic/libpmic.odrivers/rtc/librtc.odrivers/serial/libserial.odrivers/sound/libsound.odrivers/spi/libspi.odrivers/twserial/libtws.odrivers/usb/eth/libusb_eth.odrivers/usb/gadget/libusb_gadget.odrivers/usb/host/libusb_host.odrivers/usb/musb-new/libusb_musb-new.odrivers/usb/musb/libusb_musb.odrivers/usb/phy/libusb_phy.odrivers/usb/ulpi/libusb_ulpi.odrivers/video/libvideo.odrivers/watchdog/libwatchdog.ofs/cbfs/libcbfs.o fs/cramfs/libcramfs.ofs/ext4/libext4fs.o fs/fat/libfat.ofs/fdos/libfdos.o fs/jffs2/libjffs2.ofs/libfs.o fs/reiserfs/libreiserfs.ofs/ubifs/libubifs.ofs/yaffs2/libyaffs2.ofs/zfs/libzfs.olib/libfdt/libfdt.olib/libgeneric.olib/lzma/liblzma.olib/lzo/liblzo.olib/zlib/libz.onet/libnet.opost/libpost.otest/libtest.oboard/samsung/smdk2410/libsmdk2410.o--end-group /home/gus/jz2440/system/u-boot-2013.01-20160711-2440/arch/arm/lib/eabi_compat.o -L /home/toolchain/gcc-4.6.4/bin/../lib/gcc/arm-arm1176jzfssf-linux-gnueabi/4.6.4 -lgcc -Map u-boot.map -o u-bootarm-linux-objcopy -O srec u-boot u-boot.srecarm-linux-objcopy --gap-fill=0xff -O binary u-boot u-boot.bin

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