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:
) }$ |. |2 B0 Y3 \" ^3 |7 d @rm -f $(obj)include/config.h $(obj)include/config.mk \
  $(obj)board/*/config.tmp $(obj)board/*/*/config.tmp \
  _2 B0 i" Z  m8 \1 Q/ A  $(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
/ I% `1 E: z0 K7 F; g4 |. O/ \export 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
$ j' Q% T9 t1 i6 v. ~# U-Boot for a specific board.
1 q0 k$ }; Q2 G0 ~$ l#
$ P! b# z. s" r# Parameters:  Target  Architecture  CPU  Board [VENDOR] [SOC]
) {$ {$ l7 S! b, {#
# (C) 2002-2006 DENX Software Engineering, Wolfgang Denk <wd@denx.de>
  m( G# H4 n" q- {# M$ H- c- y#

APPEND=no # Default: Create new config file
BOARD_NAME="" # Name to print in make output

while [ $# -gt 0 ] ; do
9 U  o; d( N: k case "$1" in
4 f3 P3 s, `4 Y9 d7 K --) shift ; break ;;
! ]  Z+ \2 H+ M" F8 b, s- u& h -a) shift ; APPEND=yes ;;
-n) shift ; BOARD_NAME="${1%%_config}" ; shift ;;
" }+ U( d( R/ n! ] *)  break ;;
& N5 [  Q% B/ R: O# R- K0 n esac
/ X. Z6 p3 }1 ^8 ?* c) }done

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

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

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

#
- `- ~3 R; q( ~$ e+ i  X, c9 ]% t# Create link to architecture specific headers
9 x( z' i( W( B9 _0 h#
if [ "$SRCTREE" != "$OBJTREE" ] ; then
mkdir -p ${OBJTREE}/include
mkdir -p ${OBJTREE}/include2
$ e; c+ j  R4 H2 i' d2 {( [ cd ${OBJTREE}/include2
  L- B/ r8 y, E4 z5 X+ g# \7 s" ] rm -f asm
ln -s ${SRCTREE}/include/asm-$2 asm
LNPREFIX="../../include2/asm/"
cd ../include
rm -rf asm-$2
! ?( h( z" k' X% r# ~ rm -f asm
mkdir asm-$2
ln -s asm-$2 asm
" r& r0 C& K! [# c% h+ pelse
cd ./include
rm -f asm
" Q$ Z. ?8 k( ^7 f, G ln -s asm-$2 asm
fi

rm -f asm-$2/arch

if [ -z "$6" -o "$6" = "NULL" ] ; then
7 n! [- Q: @% O% g, ?) B$ `0 { ln -s ${LNPREFIX}arch-$3 asm-$2/arch
; }, B* z% ]7 X' G* X9 a7 `else
ln -s ${LNPREFIX}arch-$6 asm-$2/arch
9 v, D. X, X+ ~3 C* f! `fi

if [ "$2" = "arm" ] ; then
; ]: V  f- V+ _0 C) Y' h2 O- M rm -f asm-$2/proc
3 a0 d" ]0 C9 L ln -s ${LNPREFIX}proc-armv asm-$2/proc
fi

#
8 x8 a" b3 \0 J  u# Create include file for Make
#
echo "ARCH   = $2" >  config.mk
5 y3 a: s2 ^4 Y* P  Z# ^2 `echo "CPU    = $3" >> config.mk
. X* p4 p8 k. w: O8 Yecho "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
1 ^# x$ r& L2 N$ A3 ]8 G  @" R) W#
if [ "$APPEND" = "yes" ] # Append to existing config file
then
6 ]+ V! |9 c; }9 e! P echo >> config.h
else
+ [4 i  s/ P. j2 b! Z5 d- n2 i > config.h  # Create new config file
fi
% N4 B& v9 j! u' pecho "/* Automatically generated - do not edit */" >>config.h
echo "#include <configs/$1.h>" >>config.h
echo "#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：
  

   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 */
, @- l' ^) h2 ~# i  r#include <configs/$1.h>