u-boot下载地址：ftp://ftp.denx.de/pub/u-boot/u-boot-2013.01.01.tar.bz2
下载之后对该文件进行解压。
我试着分析smdk2410_config对应的代码执行流程，接触u-boot时间较短，有不周之处还请见谅。
通常执行u-boot第一步就是进行开发板的配置，而smdk2410的配置命令如下：
make smdk2410_config
而Makefile中对应内容如下：
775 %_config:: unconfig
776 @$(MKCONFIG) -A $(@:_config=)
因为Makefile是先执行后面的目标再执行其后的命令，所以会执行unconfig对应的目标：
770 unconfig:
771 @rm -f $(obj)include/config.h $(obj)include/config.mk 772 $(obj)board/*/config.tmp $(obj)board/*/*/config.tmp 773 $(obj)include/autoconf.mk $(obj)include/autoconf.mk.dep
unconfig目标会把以前配置产生的文件先删除掉。
$(MKCONFIG)对应mkconfig文件
当配置参数是smdk2410时，$(@:_config=)的值为smdk2410
所以相当于执行下面的内容：
mkconfig -A smdk2410
mkconfig文件内容如下：
1 #!/bin/sh -e
2
3 # Script to create header files and links to configure
4 # U-Boot for a specific board.
5 #
6 # Parameters: Target Architecture CPU Board [VENDOR] [SOC]
7 #
8 # (C) 2002-2010 DENX Software Engineering, Wolfgang Denk <[email protected]>
9 #
10
11 APPEND=no # Default: Create new config file
12 BOARD_NAME="" # Name to print in make output
13 TARGETS=""
14
15 arch=""
16 cpu=""
17 board=""
18 vendor=""
19 soc=""
20 options=""
21
22 if [ \( $# -eq 2 \) -a \( "$1" = "-A" \) ] ; then
23 # Automatic mode
24 line=`egrep -i "^[[:space:]]*${2}[[:space:]]" boards.cfg` || {
25 echo "make: *** No rule to make target \`$2_config‘. Stop." >&2
26 exit 1
27 }
28
29 set ${line}
30 # add default board name if needed
31 [ $# = 3 ] && set ${line} ${1}
32 elif [ "${MAKEFLAGS+set}${MAKELEVEL+set}" = "setset" ] ; then
33 # only warn when using a config target in the Makefile
34 cat <<-EOF
35
36 warning: Please migrate to boards.cfg. Failure to do so will
37 mean removal of your board in the next release.
38
39 EOF
40 sleep 5
41 fi
42
43 while [ $# -gt 0 ] ; do
44 case "$1" in
45 --) shift ; break ;;
46 -a) shift ; APPEND=yes ;;
47 -n) shift ; BOARD_NAME="${1%_config}" ; shift ;;
48 -t) shift ; TARGETS="`echo $1 | sed ‘s:_: :g‘` ${TARGETS}" ; shift ;;
49 *) break ;;
50 esac
51 done
52
53 [ $# -lt 4 ] && exit 1
54 [ $# -gt 7 ] && exit 1
55
56 # Strip all options and/or _config suffixes
57 CONFIG_NAME="${1%_config}"
58
59 [ "${BOARD_NAME}" ] || BOARD_NAME="${1%_config}"
60
61 arch="$2"
62 cpu=`echo $3 | awk ‘BEGIN {FS = ":"} ; {print $1}‘`
63 spl_cpu=`echo $3 | awk ‘BEGIN {FS = ":"} ; {print $2}‘`
64 if [ "$4" = "-" ] ; then
65 board=${BOARD_NAME}
66 else
67 board="$4"
68 fi
69 [ $# -gt 4 ] && [ "$5" != "-" ] && vendor="$5"
70 [ $# -gt 5 ] && [ "$6" != "-" ] && soc="$6"
71 [ $# -gt 6 ] && [ "$7" != "-" ] && {
72 # check if we have a board config name in the options field
73 # the options field mave have a board config name and a list
74 # of options, both separated by a colon (‘:‘); the options are
75 # separated by commas (‘,‘).
76 #
77 # Check for board name
78 tmp="${7%:*}"
79 if [ "$tmp" ] ; then
80 CONFIG_NAME="$tmp"
81 fi
82 # Check if we only have a colon...
83 if [ "${tmp}" != "$7" ] ; then
84 options=${7#*:}
85 TARGETS="`echo ${options} | sed ‘s:,: :g‘` ${TARGETS}"
86 fi
87 }
88
89 if [ "${ARCH}" -a "${ARCH}" != "${arch}" ]; then
90 echo "Failed: \$ARCH=${ARCH}, should be ‘${arch}‘ for ${BOARD_NAME}" 1>&2
91 exit 1
92 fi
93
94 if [ "$options" ] ; then
95 echo "Configuring for ${BOARD_NAME} - Board: ${CONFIG_NAME}, Options: ${options}"
96 else
97 echo "Configuring for ${BOARD_NAME} board..."
98 fi
99
100 #
101 # Create link to architecture specific headers
102 #
103 if [ "$SRCTREE" != "$OBJTREE" ] ; then
104 mkdir -p ${OBJTREE}/include
105 mkdir -p ${OBJTREE}/include2
106 cd ${OBJTREE}/include2
107 rm -f asm
108 ln -s ${SRCTREE}/arch/${arch}/include/asm asm
109 LNPREFIX=${SRCTREE}/arch/${arch}/include/asm/
110 cd ../include
111 mkdir -p asm
112 else
113 cd ./include
114 rm -f asm
115 ln -s ../arch/${arch}/include/asm asm
116 fi
117
118 rm -f asm/arch
119
120 if [ -z "${soc}" ] ; then
121 ln -s ${LNPREFIX}arch-${cpu} asm/arch
122 else
123 ln -s ${LNPREFIX}arch-${soc} asm/arch
124 fi
125
126 if [ "${arch}" = "arm" ] ; then
127 rm -f asm/proc
128 ln -s ${LNPREFIX}proc-armv asm/proc
129 fi
130
131 #
132 # Create include file for Make
133 #
134 ( echo "ARCH = ${arch}"
135 if [ ! -z "$spl_cpu" ] ; then
136 echo ‘ifeq ($(CONFIG_SPL_BUILD),y)‘
137 echo "CPU = ${spl_cpu}"
138 echo "else"
139 echo "CPU = ${cpu}"
140 echo "endif"
141 else
142 echo "CPU = ${cpu}"
143 fi
144 echo "BOARD = ${board}"
145
146 [ "${vendor}" ] && echo "VENDOR = ${vendor}"
147 [ "${soc}" ] && echo "SOC = ${soc}"
148 exit 0 ) > config.mk
149
150 # Assign board directory to BOARDIR variable
151 if [ -z "${vendor}" ] ; then
152 BOARDDIR=${board}
153 else
154 BOARDDIR=${vendor}/${board}
155 fi
156
157 #
158 # Create board specific header file
159 #
160 if [ "$APPEND" = "yes" ] # Append to existing config file
161 then
162 echo >> config.h
163 else
164 > config.h # Create new config file
165 fi
166 echo "/* Automatically generated - do not edit */" >>config.h
167
168 for i in ${TARGETS} ; do
169 i="`echo ${i} | sed ‘/=/ {s/=/ /;q; } ; { s/$/ 1/; }‘`"
170 echo "#define CONFIG_${i}" >>config.h ;
171 done
172
173 echo "#define CONFIG_SYS_ARCH \"${arch}\"" >> config.h
174 echo "#define CONFIG_SYS_CPU \"${cpu}\"" >> config.h
175 echo "#define CONFIG_SYS_BOARD \"${board}\"" >> config.h
176
177 [ "${vendor}" ] && echo "#define CONFIG_SYS_VENDOR \"${vendor}\"" >> config.h
178
179 [ "${soc}" ] && echo "#define CONFIG_SYS_SOC \"${soc}\"" >> config.h
180
181 cat << EOF >> config.h
182 #define CONFIG_BOARDDIR board/$BOARDDIR
183 #include <config_cmd_defaults.h>
184 #include <config_defaults.h>
185 #include <configs/${CONFIG_NAME}.h>
186 #include <asm/config.h>
187 #include <config_fallbacks.h>
188 #include <config_uncmd_spl.h>
189 EOF
190
191 exit 0
其中24行从boards.cfg中查找包含smdk2410并其后紧跟空格的行，从而可以得到：
line = smdk2410 arm arm920t - samsung s3c24x0
后续内容就是创建一些文件夹链接。
之后根据line提取出arch,cpu,board,vendor,soc,并写入到include/config.mk中，include/config.mk内容如下：
1 ARCH = arm
2 CPU = arm920t
3 BOARD = smdk2410
4 VENDOR = samsung
5 SOC = s3c24x0
然后将配置写入到include/config.h中，include/config.h内容如下：
1 /* Automatically generated - do not edit */
2 #define CONFIG_SYS_ARCH "arm"
3 #define CONFIG_SYS_CPU "arm920t"
4 #define CONFIG_SYS_BOARD "smdk2410"
5 #define CONFIG_SYS_VENDOR "samsung"
6 #define CONFIG_SYS_SOC "s3c24x0"
7 #define CONFIG_BOARDDIR board/samsung/smdk2410
8 #include <config_cmd_defaults.h>
9 #include <config_defaults.h>
10 #include <configs/smdk2410.h>
11 #include <asm/config.h>
12 #include <config_fallbacks.h>
13 #include <config_uncmd_spl.h>
这样整个配置部分就基本完成了
时间： 2024-10-08 14:58:38