chardrivers.c

2.6内核做简单的字符驱动的例子

#include "CharDrivers.h"
unsigned int test_major=0;
MODULE_LICENSE("Dual BSD/GPL");


static ssize_t read_test(struct file *file,char *buf,size_t count,loff_t *ppos)
{
	if(copy_to_user(buf,&test_major,sizeof(int)))
	{	
		return -EFAULT;
	}
	return sizeof(int);
}
static ssize_t write_test(struct file *file,const char *buf,size_t count,loff_t *ppos)
{
	if(copy_from_user(&test_major,buf,sizeof(int)))
	{	
		return -EFAULT;
	}
	return sizeof(int);
}
static int open_test(struct inode* inode,struct file* file)
{
//	MOD_INC_USE_COUNT;
	return 0;
}
static int release_test(struct inode* inode,struct file* file)
{
//	MOD_DEC_USE_COUNT;
	return 0;
}
int __init init_module(void)
{
int result;
result=register_chrdev(0,"mytest",&test_fops);
if(result<0)
{
printk(KERN_INFO "failure\n");
return result;
}
if(test_major==0)
{
test_major=result;
}
return 0;
}
void __exit cleanup_module(void)
{
unregister_chrdev(test_major,"mytest");
}
MODULE_AUTHOR("Limei Feng");
MODULE_LICENSE("Dual BSD/GPL");