2023.2.7---字符驱动

点灯实验：

//led.h
#ifndef __LED_H__
#define __LED_H__

//pe10,pf10,pe8
#define RCC 0x50000a28
#define GPIOE_MODER 0x50006000
#define GPIOE_ODR 0x50006014
#define GPIOF_MODER 0x50007000
#define GPIOF_ODR 0x50007014

#endif

//应用层代码
#include<stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include<unistd.h>
#include<stdlib.h>
#include<string.h>
int main(int argc,const char * argv[])
{
    int fd=open("/dev/mycdev",O_RDWR);
    if(fd<0)
    {
        perror("open");
        return -1;
    }
    char buf[128]="";
    while(1)
    {
        printf("请输入命令>>");
        fgets(buf,sizeof(buf),stdin);
        buf[strlen(buf)-1]='\0';
        write(fd,buf,sizeof(buf));
    }
    close(fd);
    return 0;
}

//内核层的代码
#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include<linux/uaccess.h>
#include<linux/io.h>
#include "led.h"

int major; //接收主设备号
int res;
//接收映射后的虚拟内存地址
unsigned int *vir_rcc;
unsigned int *vir_emoder;
unsigned int *vir_eodr;
unsigned int *vir_fmoder;
unsigned int *vir_fodr;
char kbuf[128]="";

//定义自己的open,read,write,release函数
int my_open(struct inode *indoe,struct file *file)
{
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}
ssize_t my_read(struct file *file,char *user,size_t size,loff_t *loff)
{
    if(size>sizeof(kbuf)) //判断kbuf的大小
    {
        size=sizeof(kbuf);
    }
    //内核空间的数据拷贝到用户空间
    res=copy_to_user(user,kbuf,size);
    if(res)
    {
        printk("copy failed\n");
        return -1;
    }
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}
ssize_t my_write(struct file *file,const char *user,size_t size,loff_t *loff)
{
    if(size>sizeof(kbuf))
    {
        size=sizeof(kbuf);
    }
    //用户空间中的数据拷贝到内核空间
    res=copy_from_user(kbuf,user,size);
    if(res)
    {
        printk("copy failed\n");
        return -1;
    }
    //判断用户在终端输入的数据
    switch(kbuf[0])
    {
    case '1':
        if(kbuf[1]=='1')
        {
            //led1亮
            *vir_eodr |= (1<<10);
        }
        else if (kbuf[1]=='0')
        {
            //led1灭
            *vir_eodr &= (~(1<<10));
        }
        break;
    case '2':
        if(kbuf[1]=='1')
        {
            *vir_fodr |= (1<<10);
        }
        else if (kbuf[1]=='0')
        {
            *vir_fodr &= (~(1<<10));
        }
        break;
    case '3':
        if(kbuf[1]=='1')
        {
            *vir_eodr |= (1<<8);
        }
        else if (kbuf[1]=='0')
        {
            *vir_eodr &= (~(1<<8));
        }
        break;
    default:break;
    }
    
    //printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}
int my_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并初始化
struct file_operations fops=
{   
    .open=my_open,
    .read=my_read,
    .write=my_write,
    .release=my_close,
};
//入口函数
static int __init mycdev_init(void)
{
    //注册字符驱动设备
    major=register_chrdev(0,"mycdev",&fops);
    if(major<0)
    {
        printk("字符设备驱动注册失败\n");
        return major;
    }
    printk("字符设备驱动注册成功,主设备号：%d",major);
    /****映射物理内存地址到虚拟内存中****/
    vir_rcc=ioremap(RCC,4);
    if(vir_rcc==NULL)
    {
        printk("rcc寄存器映射失败\n");
        return -1;
    }
    vir_emoder=ioremap(GPIOE_MODER,4);
    if(vir_emoder==NULL)
    {
        printk("emoder寄存器映射失败\n");
        return -1;
    }
    vir_eodr=ioremap(GPIOE_ODR,4);
    if(vir_eodr==NULL)
    {
        printk("eodr寄存器映射失败\n");
        return -1;
    }
    vir_fmoder=ioremap(GPIOF_MODER,4);
    if(vir_fmoder==NULL)
    {
        printk("fmoder寄存器映射失败\n");
        return -1;
    }
    vir_fodr=ioremap(GPIOF_ODR,4);
    if(vir_fodr==NULL)
    {
        printk("fodr寄存器映射失败\n");
        return -1;
    }
    (*vir_rcc) |= (3<<4);
    //初始化led1,led2,led3
    (*vir_emoder) &= (~(3<<20));
    (*vir_emoder) |= (1<<20);
    (*vir_fmoder) &= (~(3<<20));
    (*vir_fmoder) |= (1<<20);
    (*vir_emoder) &= (~(3<<16));
    (*vir_emoder) |= (1<<16);
    return 0;
}
//出口函数
static void __exit mycdev_exit(void)
{
    //注销字符设备驱动
    unregister_chrdev(major,"mycdev");
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");