Preface:
1.笔者刚学Linux驱动开发,看到网上很多说要现建立内核树。在笔者到官网下载源码时,源码下面有如下说明: If you are simply trying to build third-party modules for your kernel, you do not want this package. Install the appropriate Linux-headers package instead. 意思是,如果你只是想为内核编译第三方的模块,那么,你不需下载此源码包。安装内核头文件包或许会更适合你。
2.如果你的Ubuntu是保持更新的,你的系统是安装有内核头文件包的,不信你到/usr/src目录下查看,是不是有Linux-headers-2.6.xx-xx-generic的文件夹呢,呵呵。我现在可以说,你可以在此开发你的驱动程序了。
3.笔者也是初学,有见笑的,大家多指正
emial: tonychen123@qq.com; 转载注明出处:,作者:tony
4.环境本来就有了看来,所以我的文章,本来应该叫驱动开发最简单例子才合适……另,我要示例的是最简单,也是个最没用的驱动演示,名字叫tst,包含源码tst.c及makefile文件,编译出来的模块名叫tst.ko
Content:
1)建立你的实验目录并创建tst.c源文件:
代码:
tony@Ubuntu:~/mini2440$ mkdir mtst; cd mtst
tony@Ubuntu:~/mini2440/mtst$ vim tst.c
======================================
#include <Linux/module.h>
#include <Linux/kernel.h>
#include <Linux/init.h>
static int __init tst_start(viod)
{
printk(KERN_INFO "Loading my so simple module...\n");
printk(KERN_INFO "I love Ubuntu\n");
return 0;
}
static void __exit tst_end(void)
{
printk(KERN_INFO "From tst module: Goodbye, Tony.\n");
}
module_init(tst_start);
module_exit(tst_end);
2)创建Makefile文件:
代码:
tony@Ubuntu:~/mini2440/mtst$ vim Makefile
=================================================================
obj-m = tst.o
K_DIR = $(shell uname -r)
PWD = $(shell pwd)
all:
make -C /lib/modules/$(K_DIR)/build M=$(PWD) modules
clean:
make -C /lib/modules/$(K_DIR)/build M=$(PWD) clean
# end #
3)编译
代码:
tony@Ubuntu:~/mini2440/mtst$ sudo make Note:好像要用sudo才行!
make -C /lib/modules/2.6.28-12-generic/build M=/home/tony/mini2440/mtst modules
make[1]: Entering directory `/usr/src/Linux-headers-2.6.28-12-generic'
CC [M] /home/tony/mini2440/mtst/tst.o
/home/tony/mini2440/mtst/tst.c:19: warning: function declaration isn’t a prototype
Building modules, stage 2.
MODPOST 1 modules Note:生成一个module!
CC /home/tony/mini2440/mtst/tst.mod.o
LD [M] /home/tony/mini2440/mtst/tst.ko
make[1]: Leaving directory `/usr/src/Linux-headers-2.6.28-12-generic'
tony@Ubuntu:~/mini2440/mtst$
4)测试
代码:
tony@Ubuntu:~/mini2440/mtst$ su Note:加载模块要有root特权
Password:
root@Ubuntu:/home/tony/mini2440/mtst# insmod tst.ko Note:加载模块要有root特权
root@Ubuntu:/home/tony/mini2440/mtst# dmesg | tail
[ 25.464531] r8169: eth0: link up
[ 25.464534] r8169: eth0: link up
[ 54.931357] UDF-fs: No VRS found
[ 54.981587] ISO 9660 Extensions: Microsoft Joliet Level 3
[ 55.013712] ISOFS: changing to secondary root
[ 2932.746291] module init
[ 3138.097884] Cleanup module
[ 7444.574136] tst: module license 'unspecified' taints kernel.
[ 7444.575117] Loading my so simple module... Note:注意这两行,就是我们的模块加载信息
[ 7444.575121] I love Ubuntu
root@Ubuntu:/home/tony/mini2440/mtst# lsmod | grep tst
tst 9344 0
root@Ubuntu:/home/tony/mini2440/mtst# rmmod tst.ko
root@Ubuntu:/home/tony/mini2440/mtst# lsmod | grep tst
root@Ubuntu:/home/tony/mini2440/mtst# dmesg | tail
[ 25.464534] r8169: eth0: link up
[ 54.931357] UDF-fs: No VRS found
[ 54.981587] ISO 9660 Extensions: Microsoft Joliet Level 3
[ 55.013712] ISOFS: changing to secondary root
[ 2932.746291] module init
[ 3138.097884] Cleanup module
[ 7444.574136] tst: module license 'unspecified' taints kernel.
[ 7444.575117] Loading my so simple module...
[ 7444.575121] I love Ubuntu
[ 7559.570808] From tst module: Goodbye, Tony. Note:呵呵,模块正常卸载
root@Ubuntu:/home/tony/mini2440/mtst#