uboot - 配置过程1（分析国产君正的ingenic-linux-kernel3.10.14-x1000-v8.2-20181116\u-boot\mkconfig脚本）

=分析uboot的配置过程（mkconfig脚本）=
uboot怎么配置？我们在终端上执行make NAME_config时的运行过程解析！

STEP1:

%_config::   unconfig@$(MKCONFIG) -A $(@:_config=)

我们执行make *_config时会运行makefile的这两行程序，先分析下：
这个其实就是运行uboot根目录下的mkconfig文件，
并传入2个参数：

$1: -A
$2: $(@:_config=) :去掉目标*_config中的_config字符串也就是 *

STEP2:

然后开始运行mkconfig

STEP2.1:

APPEND=no   # Default: Create new config file
BOARD_NAME=""    # Name to print in make output
TARGETS=""arch=""
cpu=""
board=""
vendor=""
soc=""
options=""if [ \( $# -eq 2 \) -a \( "$1" = "-A" \) ] ; then# Automatic modeline=`egrep -i "^[[:space:]]*${2}[[:space:]]" boards.cfg` || {echo "make: *** No rule to make target \`$2_config'.  Stop." >&2exit 1}set ${line}# add default board name if needed[ $# = 3 ] && set ${line} ${1}
fi

这里面涉及到shell脚本if的使用语法，单分支语句结构

if [ 条件表达式 ]; then指令
fi

分析条件语句：

\( $# -eq 2 \) -a \( "$1" = "-A" \)

其中-a表示&& （语法：-o = or = ||, -a = and = && ）
( $# -eq 2 )表示：输入的参数数目=2
( “$1” = “-A” ) 表示：输入的第一个参数=-A
这里条件满足，执行内部语句。

line=`egrep -i "^[[:space:]]*${2}[[:space:]]" boards.cfg` ||{echo "make: *** No rule to make target \`$2_config'.  Stop." >&2 exit 1}

两个语句执行||。
语句1：搜索文件获得模式。-i表示当进行比较时忽略字符的大小写。表示在boards.cfg里面搜索字符串"^ [[:space:]]*${2}[[:space:]]"即含有2#参数的字符串
例如：配置命令为

make halley2_xImage_nand_spl_boot_config

在boards.cfg里面line586

halley2_xImage_nand_spl_boot   mips        xburst     halley2         ingenic        x1000       halley2:SPL_SFC_NAND,SPL_OS_BOOT,MTD_SFCNAND

如果有该行代码则赋值给line，否则打印

"make: *** No rule to make target \`$2_config'.  Stop."

同时退出。
继续！

set ${line}

表示把line中存储的变量作为本文件的输入参数，即执行该语句之前参数数量为2，执行之后为7！

STEP2.2:

while [ $# -gt 0 ] ; do          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

关于shell指令的while循环语法：

while expression
docommand
done

条件是：参数个数$# -greater than 0 then…

关于shell指令的case语法：

case $xxx in
yyy)do something;;esac

检查1#参数是否有这几个符号，这里1#参数是

halley2_xImage_nand_spl_boot

条件不满足，则不执行该语句。

STEP2.3:

[ $# -lt 4 ] && exit 1           //$# -less than 4 退出
[ $# -gt 7 ] && exit 1      //$# -great than 7 退出# Strip all options and/or _config suffixes
CONFIG_NAME="${1%_config}"[ "${BOARD_NAME}" ] || BOARD_NAME="${1%_config}"

如果定义了BOARD_NAME，则给它赋值。BOARD_NAME=halley2_xImage_nand_spl_boot_config

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

awk为shell命令，具体参见收藏具体介绍。

if [ "$4" = "-" ] ; thenboard=${BOARD_NAME}
elseboard="$4"
fi

board="$4"=halley2

STEP2.4

1#	halley2_xImage_nand_spl_boot
2#	mips
3#	xburst
4#	halley2
5#	ingenic
6#	x1000
7#	halley2:SPL_SFC_NAND,SPL_OS_BOOT,MTD_SFCNAND

[ $# -gt 4 ] && [ "$5" != "-" ] && vendor="$5"
[ $# -gt 5 ] && [ "$6" != "-" ] && soc="$6"

这里参数数量为7，两个条件均满足，所以vendor="$5" &&soc="$6"

[ $# -gt 6 ] && [ "$7" != "-" ] && {tmp="${7%:*}"        if [ "$tmp" ] ; thenCONFIG_NAME="$tmp"fi# Check if we only have a colon...if [ "${tmp}" != "$7" ] ; thenoptions=${7#*:}TARGETS="`echo ${options} | sed 's:,: :g'` ${TARGETS}"fi
}

以上条件满足，
#check if we have a board config name in the options field
# the options field mave have a board config name and a list
# of options, both separated by a colon (’:’); the options are
# separated by commas (’,’).
#
# Check for board name
#截取7#参数:前面的部分和后面的部分，分别给CONFIG_NAME和options

语法1：${VALUE%.*}或${VALUE%%.*}删除VALUE字符串中以分隔符“.”匹配的右边字符，保留左边字符。tmp="${7%:*}"这里tmp=halley2
CONFIG_NAME="$tmp"=halley2

语法2：sed是shell指令

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

语法：-a表示and，条件与
这里条件不满足。

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

options变量存在，打印以下内容Configuring for ${BOARD_NAME} - Board: ${CONFIG_NAME}, Options: ${options}=Configuring for halley2_xImage_nand_spl_boot - Board: halley2, Options: SPL_SFC_NAND,SPL_OS_BOOT,MTD_SFCNAND

STEP2.5 创建asm链接

if [ "$SRCTREE" != "$OBJTREE" ] ; thenmkdir -p ${OBJTREE}/includemkdir -p ${OBJTREE}/include2cd ${OBJTREE}/include2rm -f asmln -s ${SRCTREE}/arch/${arch}/include/asm asmLNPREFIX=${SRCTREE}/arch/${arch}/include/asm/cd ../includemkdir -p asm
elsecd ./includerm -f asmln -s ../arch/${arch}/include/asm asm
fi

条件不满足，进入else分支，创建一个名称为asm的链接文件指向../arch/${arch}/include/asm
如果提示一下错误：
不可使用共享文件夹的方式进行

STEP2.6

if [ -z "${soc}" ] ; thenln -s ${LNPREFIX}arch-${cpu} asm/arch
elseln -s ${LNPREFIX}arch-${soc} asm/arch
fi

语法1：shell脚本中的if 参数-a至-z
[-z string] “string”的长度为零则为真
这里条件不满足，执行else 创建链接文件asm/arch指向${LNPREFIX}arch-${soc}即arch-x1000

STEP2.7

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

在include/建立config.mk文件，

1.echo "ARCH   = ${arch}"   ----------------------->ARCH   = mips

2.
if [ ! -z "$spl_cpu" ] ; thenecho 'ifeq ($(CONFIG_SPL_BUILD),y)'echo "CPU    = ${spl_cpu}"echo "else"echo "CPU    = ${cpu}"echo "endif"elseecho "CPU    = ${cpu}"fi-------------------->CPU    = xburst

3.echo "BOARD  = ${board}"--------------------->BOARD  = halley2

4.echo "VENDOR = ${vendor}"--------------->VENDOR = ingenic

5.echo "SOC    = ${soc}"--------------------->SOC    = x1000

STEP2.8

#
# Create board specific header file
#
if [ "$APPEND" = "yes" ]   # Append to existing config file
thenecho >> config.h
else> config.h       # Create new config file
fi
echo "/* Automatically generated - do not edit */" >>config.h

创建文件./include/config.h,打印第一句到文件

for i in ${TARGETS} ; doi="`echo ${i} | sed '/=/ {s/=/ /;q; } ; { s/$/ 1/; }'`"echo "#define CONFIG_${i}" >>config.h ;
done

???需要查阅语法
对应文本为：

#define CONFIG_SPL_SFC_NAND  1
#define CONFIG_SPL_OS_BOOT  1
#define CONFIG_MTD_SFCNAND  1

打印下列语句到文件

echo "#define CONFIG_SYS_ARCH  \"${arch}\""  >> config.h
echo "#define CONFIG_SYS_CPU   \"${cpu}\""   >> config.h
echo "#define CONFIG_SYS_BOARD \"${board}\"" >> config.h[ "${vendor}" ] && echo "#define CONFIG_SYS_VENDOR \"${vendor}\"" >> config.h[ "${soc}"    ] && echo "#define CONFIG_SYS_SOC    \"${soc}\""    >> config.h

===

#define CONFIG_SYS_ARCH  "mips"
#define CONFIG_SYS_CPU   "xburst"
#define CONFIG_SYS_BOARD "halley2"
#define CONFIG_SYS_VENDOR "ingenic"
#define CONFIG_SYS_SOC    "x1000"

cat << EOF >> config.h
#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>
EOF

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

#define CONFIG_BOARDDIR board/ingenic/halley2
#include <config_cmd_defaults.h>
#include <config_defaults.h>
#include <configs/halley2.h>
#include <asm/config.h>
#include <config_fallbacks.h>
#include <config_uncmd_spl.h>