带paramter的驱动(book.ko)

1，代码

 1 /*
 2  * a simple kernel module supporting parameters
 3  *
 4  * Copyright (C) 2014 Barry Song  ([email protected])
 5  *
 6  * Licensed under GPLv2 or later.
 7  */
 8 
 9 #include <linux/init.h>
10 #include <linux/module.h>
11 
12 static char *book_name = "dissecting Linux Device Driver";
13 module_param(book_name, charp, S_IRUGO);
14 
15 static int book_num = 4000;
16 module_param(book_num, int, S_IRUGO);
17 
18 static int __init book_init(void)
19 {
20     printk(KERN_INFO "book name:%s\n", book_name);
21     printk(KERN_INFO "book num:%d\n", book_num);
22     return 0;
23 }
24 module_init(book_init);
25 
26 static void __exit book_exit(void)
27 {
28     printk(KERN_INFO "book module exit\n ");
29 }
30 module_exit(book_exit);
31 
32 MODULE_AUTHOR("Barry Song <[email protected]>");
33 MODULE_LICENSE("GPL v2");
34 MODULE_DESCRIPTION("A simple Module for testing module params");
35 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

 1 KVERS = $(shell uname -r)
 2 
 3 # Kernel modules
 4 obj-m += book.o
 5 
 6 # Specify flags for the module compilation.
 7 #EXTRA_CFLAGS=-g -O0
 8 
 9 build: kernel_modules
10 
11 kernel_modules:
12     make -C /lib/modules/$(KVERS)/build M=$(CURDIR) modules
13 
14 clean:
15     make -C /lib/modules/$(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