带paramter的驱动(book.ko)

1，代码

/*
 * a simple kernel module supporting parameters
 *
 * Copyright (C) 2014 Barry Song  (baohua@kernel.org)
 *
 * Licensed under GPLv2 or later.
 */

#include <linux/init.h>
#include <linux/module.h>

static char *book_name = "dissecting Linux Device Driver";
module_param(book_name, charp, S_IRUGO);

static int book_num = 4000;
module_param(book_num, int, S_IRUGO);

static int __init book_init(void)
{
    printk(KERN_INFO "book name:%s\n", book_name);
    printk(KERN_INFO "book num:%d\n", book_num);
    return 0;
}
module_init(book_init);

static void __exit book_exit(void)
{
    printk(KERN_INFO "book module exit\n ");
}
module_exit(book_exit);

MODULE_AUTHOR("Barry Song <baohua@kernel.org>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("A simple Module for testing module params");
MODULE_VERSION("V1.0");

 module_param 用来定义需要传递的参数，这里的参数都是有默认值的

 

2，makefile

KVERS = $(shell uname -r)

# Kernel modules
obj-m += book.o

# Specify flags for the module compilation.
#EXTRA_CFLAGS=-g -O0

build: kernel_modules

kernel_modules:
    make -C /lib/modules/$(KVERS)/build M=$(CURDIR) modules

clean:
    make -C /lib/modules/$(KVERS)/build M=$(CURDIR) clean

和hello驱动的makefile类似

 

3，安装驱动和查看参数

3.1 不带参数模式： insmod ./book.ko 

查看参数如下所示：

baohua@baohua-VirtualBox:/sys/module/book/parameters$ cat book_name 
dissecting Linux Device Driver
baohua@baohua-VirtualBox:/sys/module/book/parameters$ cat book_num
4000

 

 

3.2 带参数模式： insmod ./book.ko book_name='test123' book_num=500 

参数如下所示：

baohua@baohua-VirtualBox:/sys/module/book/parameters$ cat book_name 
test123
baohua@baohua-VirtualBox:/sys/module/book/parameters$ cat book_num 
500

 

 

5，卸载驱动

 rmmod book