驱动1源码

• 字符虚拟驱动

#include<linux/module.h>
#include<linux/kernel.h>
#include<linux/init.h>
#include <linux/fs.h>
//#include<linux/slab.h>
//#include<linux/io.h>
#include<linux/uaccess.h>

#define CHRDEVBASE_MAJOR    200
#define CHRDEVBASE_NAME     "chrdevbase"

static char readbuf[100];
static char writebuf[100];
static char kerneldata[] = {"kernel data!"};

static int chrdevbase_open(struct inode *inode, struct file *filp)
{
    printk("chrdevbase_open\r\n");
	return 0;
}

static int chrdevbase_release(struct inode *inode, struct file *filp)
{
    //printk("chrdevbase_release\r\n");
    return 0;
}

static ssize_t chrdevbase_read(struct file *filp, __user char *buf, size_t count,
			loff_t *ppos)
{
    int ret = 0;
    memcpy(readbuf, kerneldata, sizeof(kerneldata));
    ret = copy_to_user(buf, readbuf, count);
    if(ret == 0)
    {
        ;
    }
    else
    {
        ;
    }
    return 0;
}

static ssize_t chrdevbase_write(struct file *filp, const char __user *buf,
			 size_t count, loff_t *ppos)
{
    int ret = 0;
    ret = copy_from_user(writebuf, buf, count);
    if(ret == 0)
    {
        printk("Kernel receive data : %s\r\n", writebuf);
    }
    else
    {
        ;
    }
    return 0;
}

static struct file_operations chrdevbase_fops=
{
    .owner = THIS_MODULE,
    .open = chrdevbase_open,
    .release = chrdevbase_release,
    .read = chrdevbase_read,
    .write = chrdevbase_write,
};

static int __init chrdevbase_init(void)
{
    int ret = 0;
    printk("chrdevbase_init\r\n");
    // register char dev func
    ret = register_chrdev(CHRDEVBASE_MAJOR, CHRDEVBASE_NAME, \
				  &chrdevbase_fops);
    if(ret < 0)
    {
        printk("chrdevbase init failed\r\n");
    }
    return 0;
}

static void __exit chrdevbase_exit(void)
{
    // unregister char dev func
    unregister_chrdev(CHRDEVBASE_MAJOR, CHRDEVBASE_NAME);
    printk("chrdevbase_exit\r\n");
}

module_init(chrdevbase_init);
module_exit(chrdevbase_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("JL<MAIL ADDRESS>");

• 测试APP

#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<string.h>
// chrdevApp filename  1/2
// 1 -> read 
// 2 -> write
int main(int argc, char **argv)
{
    int ret = 0;
    int fd = 0;
    char *filename;
    char readbuf[100], writebuf[100];
    static char usrdata[] = {"user data!"};

    if(argc != 3)
    {
        printf("Error usage!\r\n");
        return -1;
    }
    filename = argv[1];
    fd = open(filename, O_RDWR);
    if(fd < 0)
    {
        printf("Can't open file \"%s\"\r\n", filename);
        return -1;
    }
    if(atoi(argv[2]) == 1)
    {
        ret = read(fd, readbuf, 50);
        if(ret < 0)
        {
            printf("Read file \"%s\" error!\r\n", filename);
            return -1;
        }
        else
        {
            printf("App read data: %s\r\n", readbuf);
        }
    }
    if(atoi(argv[2]) == 2)
    {
        memcpy(writebuf, usrdata, sizeof(usrdata));
        ret = write(fd, writebuf, 50);
        if(ret < 0)
        {
            printf("Write file \"%s\" error!\r\n", filename);
            return -1;
        }
        else
        {
            ;
        }
    }
    
    ret = close(fd);
    if(ret < 0)
    {
        printf("Close file \"%s\" error!\r\n", filename);
        return -1;
    }
    else
    {
        ;
    }

    return 0;
}