后台驱动代码如下：比较昨天的，添加了读写指针位置移动操作
#include<linux/init.h>
#include<linux/module.h>
#include<linux/kernel.h>
#include <linux/poll.h> /* COPY_TO_USER */
#include<linux/errno.h>
#include <linux/cdev.h>
#include <linux/slab.h> #define DEV_NAME "rwtest"
#define DEV_NUM 2
#define DEV_MEM_SIZE 4096 static int major=;
//static int MAX_BUF_LEN=1024;
static char drv_buffer[][];
//static char drv_buf0[1024];
//static char drv_buf1[1024];
//static int WRI_LENGTH=0;
struct cdev cdev;
struct mem_dev * mem_devp; /*璁惧缁撴瀯浣撴寚閽?/ /*mem璁惧鎻忚堪缁撴瀯浣?/
struct mem_dev
{
char *data;
unsigned long size;
}; /***********鍐欏叆*************************/
static ssize_t dx_write(struct file *filp, const char __user *buffer, size_t size, loff_t * ppos)
{
unsigned long p=*ppos;
unsigned int count =size;
int ret=;
char * data=filp->private_data ;
//struct mem_dev *dev = filp->private_data; /*鑾峰緱璁惧缁撴瀯浣撴寚閽?/
//struct mem_dev *dev=&mem_devp[0];/*鑾峰緱璁惧缁撴瀯浣撴寚閽? [0]*/
printk("data:::%s\n",data);
if(p>=DEV_MEM_SIZE)return ;
if(count>DEV_MEM_SIZE-p)
{
count=DEV_MEM_SIZE-p;
}
printk("write p::%ld\n",p);
/*浠庤繃鎴风┖闂村啓鍏ユ暟鎹?/
if(copy_from_user(data + p,buffer,count))
{
ret=-EFAULT;
}
else
{
*ppos +=count;
ret=count;
printk(KERN_INFO "written %d bytes from %ld\n",count,p);
}
printk("write:%s\n",(char *)(filp->private_data+p));
printk("write buffer:%s\n",buffer);
return count;
}
/**************************************璇诲彇***********************************************/
static ssize_t dx_read(struct file *filp, char __user *buffer, size_t size, loff_t *ppos)
{
//鏂囦欢璇诲彇浣嶇疆
unsigned long p=*ppos;
unsigned int count =size;//瑕佽鍙栫殑,澶у皬
int ret=;
char * data=filp->private_data ;
//struct mem_dev *dev = filp->private_data; /*鑾峰緱璁惧缁撴瀯浣撴寚閽?/
//struct mem_dev *dev=&mem_devp[0];/*鑾峰緱璁惧缁撴瀯浣撴寚閽? [0]*/ if(p>=DEV_MEM_SIZE)
return ;
if(count>DEV_MEM_SIZE-p)
{
count=DEV_MEM_SIZE-p;
}
printk("read p::%ld\n",p);
/*浠庢暟鎹鍒扮敤鎴风┖闂?*/
if(copy_to_user(buffer,data + p,count))
{
ret=-EFAULT;
}
else
{
*ppos +=count;
ret=count;
printk(KERN_INFO "written %d bytes from %ld\n",count,p);
}
printk("read:%s\n",(char *)(filp->private_data));
printk("read buffer:%s\n",buffer);
return count;
}
//===========================鎵撳紑=========================================
static int dx_open(struct inode *inode, struct file *filp)
{
//printk("device open sucess!\n");
//struct mem_dev *dev;
/*鑾峰彇娆¤澶囧彿*/
int num = MINOR(inode->i_rdev); if (num >= DEV_NUM)
return -ENODEV;
//dev = &mem_devp[num];
//dev = drv_buffer[num];
printk("num:%d\n",num);
/*灏嗚澶囨弿杩扮粨鏋勬寚閽堣祴鍊肩粰鏂囦欢绉佹湁鏁版嵁鎸囬拡*/
filp->private_data = drv_buffer[num];
filp->f_pos +=strlen(drv_buffer[num]);
printk("open:%s\n",(char *)filp->private_data);
return ;
}
/**********************************release***************************************************/
static int dx_release(struct inode *inode, struct file *filp)
{
printk("device release\n");
return ;
} static loff_t dx_llseek(struct file *filp, loff_t offset, int whence)
{
loff_t newpos; switch(whence) {
case : /* SEEK_SET */
newpos = offset;//鏂囦欢寮€濮嬩綅缃姞鍋忕Щ閲? break;
case : /* SEEK_CUR */
newpos = filp->f_pos + offset;//褰撳墠鎸囬拡浣嶇疆鍔犲亸绉婚噺
break;
case : /* SEEK_END */
newpos = DEV_MEM_SIZE - + offset;//鏂囦欢鏈熬鍔犲亸绉婚噺(鏈€鍚庝竴浣嶄负'\0')
break;
default: /* can't happen */
return -EINVAL;
}
if ((newpos<) || (newpos>DEV_MEM_SIZE))
return -EINVAL;
filp->f_pos = newpos;
return newpos;
} //===============缁撴瀯浣?椹卞姩鍚勫睘鎬?=========
static struct file_operations file_opt = {
.owner= THIS_MODULE,
.llseek= dx_llseek,
.write= dx_write,
.read= dx_read,
.open= dx_open,
.release=dx_release,
};
//----------------------------------------------------------------------
static int __init qudong_init(void)
{
int ret;
ret = register_chrdev(, DEV_NAME, &file_opt);
if(ret<)
{
printk(DEV_NAME " can't get major number\n");
return ;
}
major=ret;
printk("dx module major number is %d\n", ret);
return ;
}
//-----------------------------------------------------------------------
static void __exit qudong_exit(void)
{
/*娉ㄩ攢璁惧*/
cdev_del(&cdev);
//kfree(mem_devp); /*閲婃斁璁惧缁撴瀯浣撳唴瀛?/
unregister_chrdev_region(MKDEV(major,),);/*閲婃斁璁惧鍙?/
printk("exit\n");
}
module_init(qudong_init);
module_exit(qudong_exit);
MODULE_LICENSE("GPL");/*浣跨敤鏉冮檺*/
MODULE_AUTHOR("Made in China <china@hotmail.com>");/*浣滆€?/
MODULE_DESCRIPTION("s3c6410 Hypervisor Filesystem");/*鐗堟湰*/
测试代码如下：
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include<string.h>
int main()
{
int fd0=;
int fd1=;
int ret=;
char bufw[]={'\0'};
char bufr[]={'\0'};
char bufw1[]={'\0'};
char bufr1[]={'\0'};
fd0=open("/dev/rw0",O_RDWR);
if(fd0<)
{
perror("open error\n");
return ;
}
fd1=open("/dev/rw1",O_RDWR);
if(fd1<)
{
perror("open error\n");
return ;
}
printf("Please input string:\n");
scanf("%s",bufw);
ret=write(fd0,bufw,strlen(bufw));
if(ret<)
{
perror("write bufw error\n");
return ;
}
printf("burw====%s\n",bufw);
printf("Please input string:\n");
scanf("%s",bufw1);
ret=write(fd1,bufw1,strlen(bufw1));
if(ret<)
{
perror("write bufw1 error\n");
return ;
}
printf("burw1====%s\n",bufw1);
int num0=strlen(bufw);
printf("num0:%d\n",num0);
lseek(fd0,-(num0),SEEK_CUR);
//lseek(fd0,0,SEEK_CUR);
ret=read(fd0,bufr,);
if(ret<)
{
perror("read bufr error\n");
return ;
}
printf("bufr====%s\n",bufr);
int num1=strlen(bufw1);
printf("num1:%d\n",num1);
lseek(fd1,-(num1),SEEK_CUR);
//lseek(fd1,0,SEEK_SET);
ret=read(fd1,bufr1,);
if(ret<)
{
perror("read bufr1 error\n");
return ;
}
printf("bufr1====%s\n",bufr1); close(fd0);
close(fd1);
return ;
}
Makefile文件：
## Makefile template. obj-m := qudong.o
UNAME := $(shell uname -r)
PWD := $(shell pwd)
ADVMOD := qudong defualt:
@make -C /lib/modules/$(UNAME)/build SUBDIRS=$(PWD) modules clean:
@rm -f *.o
@rm -f *.ko
@rm -f *.mod.c
@rm -f .*.cmd
@rm -rf .tmp_versions
#endif