驱动开发day2 - 技术栈

通过物理内存映射为虚拟内存实现三盏LED灯亮灯灭

head.h

#ifndef __HEAD_H__
#define __HEAD_H__

#define PHY_LED1_MODER 0X50006000
#define PHY_LED1_ODR 0X50006014
#define PHY_RCC 0x50000A28

#define PHY_LED2_MODER 0X50007000
#define PHY_LED2_ODR 0X50007014

#define PHY_LED3_MODER 0X50006000
#define PHY_LED3_ODR 0X50006014

#endif

test.c

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
int main(int argc,char const *argv[])
{
    char buf[128] = {0};
    int fd = open("/dev/mychrdev",O_RDWR);
    if(fd < 0 )
    {
        printf("打开设备文件失败\n");
        return -1;
    }
    printf("打开设备文件成功\n");
    while(1)
    {
        printf("请输入要进行的操作：0(关灯)1(开灯)>");
        fgets(buf,sizeof(buf),stdin);//在终端第一个字符串
        buf[strlen(buf)-1]='\0';
        write(fd,buf,sizeof(buf));//将数据传递给内核
    }
   
    close(fd);
    return 0;
}

demo.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include "head.h"

unsigned int major;
char kbuf[128]={};
//LED1定义三个指针指向映射后的虚拟内存
unsigned int *vir_moder1;
unsigned int *vir_odr1;
unsigned int *vir_rcc;
//LED2定义三个指针指向映射后的虚拟内存
unsigned int *vir_moder2;
unsigned int *vir_odr2;

//LED3定义三个指针指向映射后的虚拟内存
unsigned int *vir_moder3;
unsigned int *vir_odr3;


//封装操作方法
int mycdev_open(struct inode *inode,struct file *file)
{
	printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
	return 0;
}

ssize_t mycdev_read(struct file *file,char *ubuf,size_t size,loff_t *lof)
{
	printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
	int ret;
	ret=copy_to_user(ubuf,kbuf,size);
	if(ret)
	{
		printk("copy_to_user filed\n");
		return -EIO;
	}
	return 0;
}
ssize_t mycdev_write(struct file *file,const char *ubuf,size_t size,loff_t *lof)
{
	printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
	int ret;
	ret=copy_from_user(kbuf,ubuf,size);
	if(ret)
	{
		printk("copy_from_user filed\n");
		return -EIO;
	}
	if(kbuf[0] == '0')//关灯
	{
		//关灯逻辑
		(*vir_odr1) &= (~(0x1 << 10));
		(*vir_odr2) &= (~(0x1 << 10));
		(*vir_odr3) &= (~(0x1 << 8));
	}
	else if(kbuf[0]=='1')
	{
		//开灯逻辑
		(*vir_odr1) |= (0x1 << 10); 
		(*vir_odr2) |= (0x1 << 10); 
		(*vir_odr3) |= (0x1 << 8); 
	}
	
	return 0;
}
int mycdev_close(struct inode *inode,struct file *file)
{
	printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
	return 0;
}
//定义操作方法结构体对象
struct file_operations fops = {
	.open=mycdev_open,
	.read=mycdev_read,
	.write=mycdev_write,
	.release=mycdev_close,
};

//入口函数，安装内核模块时执行
static int __init mycdev_init(void)
{
	//注册字符设备
	major = register_chrdev(0,"mychrdev",&fops);
	if(major < 0)
	{
		printk("字符设备驱动注册失败\n");
		return major;
	}
	printk("注册字符设备驱动成功major=%d\n",major);
	vir_rcc = ioremap(PHY_RCC,4);
	if(vir_rcc ==NULL)
	{
		printk("物理内存地址映射失败%d\n",__LINE__);
		return -EFAULT;
	}
	//----------LED1进行寄存器的地址映射------------------//
	vir_moder1 = ioremap(PHY_LED1_MODER,4);
	if(vir_moder1 == NULL)
	{
		printk("物理内存地址映射失败%d\n",__LINE__);
		return -EFAULT;
	}
	vir_odr1 = ioremap(PHY_LED1_ODR,4);
	if(vir_odr1 == NULL)
	{
		printk("物理内存地址映射失败%d\n",__LINE__);
		return -EFAULT;
	}
	printk("LED1寄存器内存映射成功\n");

	//----------LED2进行寄存器的地址映射------------------//
	vir_moder2 = ioremap(PHY_LED2_MODER,4);
	if(vir_moder2 == NULL)
	{
		printk("物理内存地址映射失败%d\n",__LINE__);
		return -EFAULT;
	}
	vir_odr2 = ioremap(PHY_LED2_ODR,4);
	if(vir_odr2 == NULL)
	{
		printk("物理内存地址映射失败%d\n",__LINE__);
		return -EFAULT;
	}
	printk("LED2寄存器内存映射成功\n");
	//----------LED3进行寄存器的地址映射------------------//
	vir_moder3 = ioremap(PHY_LED3_MODER,4);
	if(vir_moder3 == NULL)
	{
		printk("物理内存地址映射失败%d\n",__LINE__);
		return -EFAULT;
	}
	vir_odr3 = ioremap(PHY_LED3_ODR,4);
	if(vir_odr3 == NULL)
	{
		printk("物理内存地址映射失败%d\n",__LINE__);
		return -EFAULT;
	}
	printk("LED3寄存器内存映射成功\n");

	//LED1寄存器初始化
	(*vir_rcc) |= (0x3 << 4);//GPIOE/GPIOF控制器时钟使能
	(*vir_moder1) &= (~(0x3 << 20));//MODER[21:20]->00
	(*vir_moder1) |= (0x1 << 20);//MODER[21:20]->01
	(*vir_odr1) &= (~(0x1 << 10));//默认关灯

	//LED2寄存器初始化	
	(*vir_moder2) &= (~(0x3 << 20));//MODER[21:20]->00
	(*vir_moder2) |= (0x1 << 20);//MODER[21:20]->01
	(*vir_odr2) &= (~(0x1 << 10));//默认关灯

	//LED3寄存器初始化
	(*vir_moder3) &= (~(0x3 << 16));//MODER[17:16]->00
	(*vir_moder3) |= (0x1 << 16);//MODER[17:16]->01
	(*vir_odr3) &= (~(0x1 << 8));//默认关灯
	return 0;
}

//出口函数，卸载内核模块时执行
static void __exit mycdev_exit(void)
{
	//取消内存映射
	iounmap(vir_rcc);
	//LED1取消内存映射
	iounmap(vir_moder1);
	iounmap(vir_odr1);

	//LED2取消内存映射
	iounmap(vir_moder2);
	iounmap(vir_odr2);

	//LED3取消内存映射
	iounmap(vir_moder3);
	iounmap(vir_odr3);

	//注销字符设备驱动
	unregister_chrdev(major,"mychrdev");
}

//用于声明入口函数
module_init(mycdev_init);
//用于声明出口函数
module_exit(mycdev_exit);
//声明当前内核模块遵循GPL协议
MODULE_LICENSE("GPL");