华清远见（上海中心）

日期：11月19日             

一、题目

1. 在串口工具进行输入：   
    echo 1 > /dev/myled0 ---->led1灯点亮
    echo 0 > /dev/myled0 ---->led1灯熄灭
    echo 1 > /dev/myled1 ---->led1灯点亮
    echo 0 > /dev/myled1 ---->led1灯熄灭
    echo 1 > /dev/myled2 ---->led1灯点亮
    echo 0 > /dev/myled2 ---->led1灯熄灭

代码实现：

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include "mycdev.h"
#define CNAME "myled"
struct cdev *cdev;
struct class *cls;
struct device *device;
dev_t dev;
int *virt_RCC;
gpio_t *virt_GPIOE;
gpio_t *virt_GPIOF;
unsigned int major;
unsigned int minor = 0;
unsigned int count=3;
char buf[128]={0};
int myc_open(struct inode *inode, struct file *file)
{
	minor = MINOR(inode->i_rdev);
	file->private_data = (void*)minor;
	
	return 0;
}
ssize_t myc_read(struct file *file, char __user *user, size_t size, loff_t *ft)
{
	return 0;
}
ssize_t myc_write(struct file *file, const char __user *user, size_t size, loff_t *ft)
{
	int ret;
	minor = ((int*)file->private_data);
	if(size > sizeof(user)) size = sizeof(buf);
	ret = copy_from_user(buf,user,sizeof(user));
	if(ret)
	{
		printk("copy from user is error\n");
		return -EIO; 
	}
	switch(minor)
	{
	case LED1:
		if(buf[0]=='1')
		{
			virt_GPIOE->ODR |=(0x1<<10);
		}
		else
		{
			virt_GPIOE->ODR &=(~(0x1<<10));
		}
		break;
	
	case LED2:
		if(buf[0]=='1')
		{
			virt_GPIOF->ODR |=(0x1<<10);
		}
		else
		{
			virt_GPIOF->ODR &=(~(0x1<<10));
		}
		break;
	case LED3:
		if(buf[0]=='1')
		{
			virt_GPIOE->ODR |=(0x1<<8);
		}
		else
		{
			virt_GPIOE->ODR &=(~(0x1<<8));
		}
		break;
	}
	return 0;
}
int myc_close(struct inode *inode, struct file *file)
{
	return 0;
}
const struct file_operations fops ={
	.open=myc_open,
	.read=myc_read,
	.write=myc_write,
	.release=myc_close,
};
static int __init mycdev_init(void)
{
	int ret;
	int i;
	//映射虚拟地址
	virt_RCC = ioremap(RCC_ENABLE,sizeof(int));
	virt_GPIOE = ioremap(GPIOE,sizeof(gpio_t));
	virt_GPIOF = ioremap(GPIOF,sizeof(gpio_t));
	//1.分配cdev结构体
	cdev = cdev_alloc();
	if(NULL == cdev)
	{
		printk("cdev alloc is error\n");
		printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
		ret = -EIO;
		goto ERR1;
	}
    //2.初始化结构体
	cdev_init(cdev,&fops);
    //3.申请设备号
	ret = alloc_chrdev_region(&dev,minor,count,CNAME);
	if(ret)
	{
		printk("alloc chrdev region is filed\n");
		printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
		ret = -ENOMEM;
		goto ERR2;
	}
    //4.驱动的注册
	ret = cdev_add(cdev,dev,count);
	if(ret)
	{
		printk("cdev add is filed\n");
		printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
		ret = -ENOMEM;
		goto ERR3;
	}
    //5.自动创建设备节点
	//向上层提交目录信息
	cls = class_create(THIS_MODULE,CNAME);
	if(IS_ERR(cls))
	{
		printk("class create is failed\n");
		ret = PTR_ERR(cls);
		goto ERR4;
	}
	//向上层提交设备节点
	major = MAJOR(dev);
	minor = MINOR(dev);
	for(i=0;i
	{
		device = device_create(cls,NULL,MKDEV(major,i),NULL,"myled%d",i);
		if(IS_ERR(device))
		{
			printk("device create is error\n");
			ret = PTR_ERR(device);
			goto ERR5;
		}
	}
	//LED灯初始化
	//将PE10引脚初始化
	//RCC使能
	*virt_RCC |=(0x1<<4);
	//将GPIOE_MODER设置为输出模式
	virt_GPIOE->MODER &=(~(0x3<<20));
	virt_GPIOE->MODER |=(0x1<<20);
	//将GPIOE_ODR设置为低电平
	virt_GPIOE->ODR &=(~(0x1<<10));
	//将PF10引脚初始化
	//RCC使能
	*virt_RCC |=(0x1<<5);
	//将GPIOE_MODER设置为输出模式
	virt_GPIOF->MODER &=(~(0x3<<20));
	virt_GPIOF->MODER |=(0x1<<20);
	//将GPIOE_ODR设置为低电平
	virt_GPIOF->ODR &=(~(0x1<<10));
	//将PE8引脚初始化
	//RCC使能
	*virt_RCC |=(0x1<<4);
	//将GPIOE_MODER设置为输出模式
	virt_GPIOE->MODER &=(~(0x3<<16));
	virt_GPIOE->MODER |=(0x1<<16);
	//将GPIOE_ODR设置为低电平
	virt_GPIOE->ODR &=(~(0x1<<8));
	return 0;
	ERR5:
		for(--i;i>=0;i--)
		{
			device_destroy(cls,MKDEV(major,i));
		}
		class_destroy(cls);
	ERR4:
		cdev_del(cdev);
	ERR3:
		unregister_chrdev_region(dev,count);
	ERR2:
		kfree(cdev);
	ERR1:
		return -EIO;
}
static void __exit mycdev_exit(void)
{
	int i;
	//取消映射
	iounmap(virt_GPIOE);
	iounmap(virt_GPIOF);
	
	//1.销毁设备节点信息
	for(i=0;i
	{
		device_destroy(cls,MKDEV(major,i));
	}
    //2.销毁目录信息
	class_destroy(cls);
    //3.驱动的注销
	cdev_del(cdev);
    //4.销毁设备号
	unregister_chrdev_region(dev,count);
    //5.释放cdev结构体
	kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

#ifndef __MYCDEV_H__
#define __MYCDEV_H__
typedef struct{
    volatile unsigned int MODER;
    volatile unsigned int OTYPER;
    volatile unsigned int OSPEEDR;
    volatile unsigned int PUPDR;
    volatile unsigned int IDR;
    volatile unsigned int ODR;
}gpio_t;
typedef enum{
	LED1,
	LED2,
	LED3
}led_t;
#define RCC_ENABLE 0x50000A28
#define GPIOE 0x50006000
#define GPIOF 0x50007000
#endif

#指定架构变量名
ARCH?=x86
#指定编译文件名
modname?=demo
 
ifeq ($(ARCH),arm)
#定义一个变量，存放linux内核源码的路径,编译完成之后，生成ARM架构，在开发板运行
KERNEDIR:=/home/ubuntu/linux-5.10.61
else
#定义一个变量，存放ubuntu中linux内核源码的路径,编译完成之后，生成X86架构，在开发板运行
KERNEDIR:=/lib/modules/$(shell uname -r)/build
endif
#PWD是自己定义的一个变量，$(shell pwd)开启一个终端，执行pwd命令，将执行的结果赋值给PWD变量
PWD:=$(shell pwd)
KBUILD_EXTRA_SYMBOLS:=/home/ubuntu/驱动/drivers/mydriver/02_EXPORT/demoA/Module.symvers
all:
	make -C $(KERNEDIR) M=$(PWD) modules
clean:
	make -C $(KERNEDIR) M=$(PWD) clean
#指定模块化方式编译的文件
obj-m:=$(modname).o

现象实现：

LED1：

 LED2：

LED3：