u-boot的Makefile分析之一make smdk2410_config

kenson

在编译U-BOOT之前，先要执行

# make smdk2410_config

定义：

smdk2410_config : unconfig

@$(MKCONFIG) $(@:_config=) arm arm920t smdk2410 samsung s3c24x0

根据依赖关系，会先执行unconfig目标

定义：

unconfig:
9 M9 G, N9 J' }/ L5 @: K4 A# v6 F @rm -f $(obj)include/config.h $(obj)include/config.mk \
) q  h1 k) w3 c1 W# J# I, }  $(obj)board/*/config.tmp $(obj)board/*/*/config.tmp \
  $(obj)include/autoconf.mk $(obj)include/autoconf.mk.dep

注意不指定输出目标时，obj,src变量均为空，unconfig下面的命令清理上一次执行make *_config时生成的头文件和makefile的包含文件。主要是include/config.h 和include/config.mk文件

MKCONFIG 是顶层目录下的mkcofig脚本文件，后面五个是传入的参数

定义：

MKCONFIG := $(SRCTREE)/mkconfig
8 K: ]# P7 s5 T% \0 ~1 ?2 e2 h2 Xexport MKCONFIG

执行：

@$(MKCONFIG) $(@:_config=) arm arm920t smdk2410 samsung s3c24x0

$(@:_config=) ：Target

arm：Architecture

arm920t ：CPU

smdk2410 ：Board

samsung ：VENDOR

s3c24x0：SOC

对于S3C2410和S3C2440，两种都被称为SOC（System on Chip）,这上面除了CPU外，还集成了包括UART、USB控制器、Nand Flash控制器等设备（称为片内外设）。S3C2410的CPU为ARM920T。

$(@:_config=) 的结果就是将“smdk2410_config”中的“_config”去掉，结果为“smdk2410”。

所以“make smdk2410_config”实际上就是执行如下命令：

unconfig

./mkconfig smdk2410 arm arm920t smdk2410 samsung s3c24x0

再看mkconfig的作用：

#!/bin/sh -e

# Script to create header files and links to configure
# U-Boot for a specific board.
! Q* D6 U9 v, u. R* H3 Y8 w#
# 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
( E; E- R9 I) W1 B0 A, d5 ? case "$1" in
--) shift ; break ;;
-a) shift ; APPEND=yes ;;
-n) shift ; BOARD_NAME="${1%%_config}" ; shift ;;
) F+ \, `/ v7 T$ ^5 n2 ], H *)  break ;;
esac
done

[ "${BOARD_NAME}" ] || BOARD_NAME="$1"

[ $# -lt 4 ] && exit 1
[ $# -gt 6 ] && exit 1

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

#
  b2 d' Z+ H2 a! Y# 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
$ z( ]! u# s% ^( S! H% z LNPREFIX="../../include2/asm/"
5 P3 g# k# u6 K3 |* C, a cd ../include
5 E% _7 F1 X- ~0 ~% Q  _7 u% X rm -rf asm-$2
, Y6 N+ D/ X2 [8 j7 r  ~) v7 A- B rm -f asm
& Z" C$ y& R# }+ D' V; U; X! \$ k! f mkdir asm-$2
. J+ w; Q  T; n% D ln -s asm-$2 asm
' f6 G4 Z: t. K7 d; Melse
cd ./include
rm -f asm
ln -s asm-$2 asm
- b/ x) W+ b! ?fi

rm -f asm-$2/arch

if [ -z "$6" -o "$6" = "NULL" ] ; then
4 _2 I" e! Y1 ]  Z. k, R ln -s ${LNPREFIX}arch-$3 asm-$2/arch
, d. ?4 O7 F+ O4 e- belse
ln -s ${LNPREFIX}arch-$6 asm-$2/arch
fi

if [ "$2" = "arm" ] ; then
rm -f asm-$2/proc
ln -s ${LNPREFIX}proc-armv asm-$2/proc
fi

#
8 _1 l8 Q9 m; o3 u  o# 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
#
- S6 F- f5 U; B9 B5 Lif [ "$APPEND" = "yes" ] # Append to existing config file
3 N7 t5 m: o, n1 `then
echo >> config.h
else
> config.h  # Create new config file
- v) ]3 B3 N% z5 v4 Dfi
$ r3 D% G# r, q$ Secho "/* Automatically generated - do not edit */" >>config.h
echo "#include <configs/$1.h>" >>config.h
echo "#include <asm/config.h>" >>config.h

exit 0

' b7 Y) m" k4 J

执行./mkconfig smdk2410 arm arm920t smdk2410 samsung s3c24x0命令，假设执行

的是“./mkconfig $1 $2 $3 $4 $5 $6”，将产生如下结果。

• 开发板名称BOARD_NAME等于$1。
• 创建到平台/开发板相关的头文件的链接，如下所示：
  & Z5 u2 _. o3 c. r& I

   ln -s asm-$2 asm

   ln -s arch-$6 asm-$6/arch

   ln -s proc-armv asm-$2/proc

   3.  创建顶层Makefile包含的文件include/config.mk，如下所示：

  ARCH = $2

  CPU = $3

BOARD = $4

VENDOR =$5

SOC =$6

    4.  创建开发板相关的头文件include/config.h,如下所示：

/* Automatically generated - do not edit */
5 s$ [" u% b/ u/ a#include <configs/$1.h>