hello.c

Linux 2.6内核版本下的PCI字符驱动开发练习参考代码。

/*
 *	hello moule practicing......
 */

// ifndef compile
#ifndef __KERNEL__
#  define __KERNEL__
#endif
#ifndef MODULE
#  define MODULE
#endif

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

/*************************************************************************/
#include	<linux/kernel.h>	/*printk();*/
#include	<linux/fs.h>	/*do everything...*/
#include	<linux/types.h>	/*size_t*/
#include	<asm/segment.h>	/*asm opt*/

//#include	"sysdep.h"	/*define header*/
/**************************************************************************/

MODULE_AUTHOR("Mr.DwG");
MODULE_LICENSE("GPL");

//static char *Version = "$Revision: 1.9 $";

MODULE_DESCRIPTION("hello_Driver");
MODULE_VERSION("$Revision: 1.9 $");

/* MODULE_DEVICE_TABLE(table_info);*/
/* MODULE_ALIAS(alternate_name);	*/

//=======================================================
/* static char *whom = "world";
 * static int howmany = 1;
 * module_param(howmany, int, S_IRUGO);
 * module_param(whom, charp, S_IRUGO);
 */

//=======================================================
/* 
 * 头文件, 包含在建立的内核版本信息.
 * LINUX_VERSION_CODE
 * 整型宏定义, 对 #ifdef 版本依赖有用.
 * EXPORT_SYMBOL (symbol);
 * EXPORT_SYMBOL_GPL (symbol);
 * 宏定义, 用来输出一个符号给内核. 第 2 种形式输出没有版本信息, 第 3 种限制输出给 GPL 许
 * 可的模块.
 * MODULE_AUTHOR(author);
 * MODULE_DESCRIPTION(description);
 * MODULE_VERSION(version_string);
 * MODULE_DEVICE_TABLE(table_info);
 * MODULE_ALIAS(alternate_name);
 * 放置文档在目标文件的模块中.
 */

//========================================================
/* #include <linux/moduleparam.h>
 * module_param(variable, type, perm);
 * 宏定义, 创建模块参数, 可以被用户在模块加载时调整( 或者在启动时间, 对于内嵌代码). 类
 * 型可以是 bool, charp, int, invbool, short, ushort, uint, ulong, 或者 intarray.
 * #include <linux/kernel.h>
 * int printk(const char * fmt, ...);
 * 内核代码的 printf 类似物.
 * 
 */
//=========================================================

/*****************************define OPT********************/

//static int hello_probe(struct pci_dev *pdev, const struct pci_device_id *pci_id);
//static int hello_release(struct inode *inode, struct file *filp);
//static int hello_open(struct inode *inode, struct file *filp);
//static int hello_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg);
//static int hello_write(struct file *filp, char *buff, size_t count, loff_t *ppos);
static int hello_read(struct file *filp, char *buff, size_t count, loff_t *ppos);


//static void hello_remove(struct pci_dev *pdev);

int hello_major=0;
char hello_buf[1024];


static int hello_read(struct file *filp, char *buff, size_t count, loff_t *ppos)
{
	//printk(KERN_DEBUG"read:file %x,buf %x,count %long int\n",filp,buff,count);
	printk(KERN_DEBUG"Hi ,hello \n");
	//memcpy(buff,hello_buf,count);
	return count;
}


int extend_function(int a,int b)
{
	return a+b;
}



static int hello_write(struct inode *inode,struct file *filp,char *buf,size_t count)
{
	printk(KERN_DEBUG"write: start");
	return 0;
}


static struct file_operations hello_fops = {
  NULL, // .owner=      THIS_MODULE,    
  NULL, // .ioctl=      evoc_ioctl,    
  NULL, // .open=       evoc_open,    
  NULL, //  .release=    evoc_release,
  		.write=		hello_write,
    	.read=		hello_read,
};

/***********************************************************************************************/

static int	__init  hello_init(void)
{
   printk(KERN_ALERT"Hello,word\n");
   	
	int result;
   	/*
   	*** Register your major, and accept a dynamic number
   	*/
	result = register_chrdev(hello_major,"hello",&hello_fops);
	if(result<0) return result;
	if(hello_major==0) hello_major=result; /*dynamic*/

	int i=extend_function(2,3);
	printk("import: you may tel that 2+3=%d\n",i);
	
	/*
	**** allocate the divices--we cannot have them static ,as the number
	**** can be specified at load time
	*/
	
   return 0;
}

static void  __exit  hello_exit(void)
{
  	unregister_chrdev(hello_major,"hello");
	printk(KERN_ALERT"Goodby,cruelwork\n");
}


module_init(hello_init);
module_exit(hello_exit);