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:
@rm -f $(obj)include/config.h $(obj)include/config.mk \
" u* ^$ A' o  u9 C  $(obj)board/*/config.tmp $(obj)board/*/*/config.tmp \
$ o& \0 `& L4 D! M  l; E" x& I  $(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
& }. k( \, Q( G* t% f4 t2 I5 R' Dexport 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
2 L3 ~: i! B( ]5 _4 n# U-Boot for a specific board.
  m5 x! C1 _9 E#
# Parameters:  Target  Architecture  CPU  Board [VENDOR] [SOC]
#
$ a4 P( K* B% P- `, E# (C) 2002-2006 DENX Software Engineering, Wolfgang Denk <wd@denx.de>
+ {) _% _( C! @# e, [9 V. u' ]#

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 ;;
' o" P' @# M7 R$ w) p  f esac
, k, a- _/ X- S- Q* p1 d6 @done

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

[ $# -lt 4 ] && exit 1
# j4 I. X5 r8 Z+ |7 ][ $# -gt 6 ] && exit 1

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

#
! J3 O2 N$ ~9 q, R# Create link to architecture specific headers
6 G1 X' U0 N2 b% s/ N0 Y: w#
1 P0 z0 c% L& A& Iif [ "$SRCTREE" != "$OBJTREE" ] ; then
  F  Y6 I4 u+ s; N mkdir -p ${OBJTREE}/include
mkdir -p ${OBJTREE}/include2
2 Z; Q$ a) B+ _ cd ${OBJTREE}/include2
rm -f asm
ln -s ${SRCTREE}/include/asm-$2 asm
) f& B  O; s3 i' k0 T! T LNPREFIX="../../include2/asm/"
cd ../include
rm -rf asm-$2
rm -f asm
4 R' i, E8 k- ?, v/ C3 N: n mkdir asm-$2
ln -s asm-$2 asm
else
cd ./include
, I5 j8 z* K, V" a9 d rm -f asm
) P' ^- c! o  A/ t1 I# V ln -s asm-$2 asm
fi

rm -f asm-$2/arch

if [ -z "$6" -o "$6" = "NULL" ] ; then
* ~& b' }" {6 B, c: ]* g6 f' l' { ln -s ${LNPREFIX}arch-$3 asm-$2/arch
else
# B/ [  R0 D+ B% D 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

#
( p+ _9 U$ }8 H3 v. F# Create include file for Make
#
, R) }: L) G. z( m: }* V7 N) S7 Aecho "ARCH   = $2" >  config.mk
. ?* ]8 T, \1 Oecho "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 [ "$APPEND" = "yes" ] # Append to existing config file
then
9 ]; C9 P1 K- Y' o echo >> config.h
% P/ V( \6 i' a6 \7 D( {' V! @else
> config.h  # Create new config file
" `& F. P$ W4 `6 K8 B+ }fi
) X) g2 o  o& l  A* j6 P6 Vecho "/* Automatically generated - do not edit */" >>config.h
echo "#include <configs/$1.h>" >>config.h
; G& f  ?( A# f* fecho "#include <asm/config.h>" >>config.h

exit 0

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：
  ( V) R8 D+ l7 @4 }

   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 */
1 e  {; {6 n. {6 `1 O" [; H#include <configs/$1.h>