2023-3-16

已于 2023-03-16 21:26:28 修改
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文章标签： linux
于 2023-03-16 21:09:49 首次发布
版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。
本文链接：https://blog.youkuaiyun.com/ljiijo/article/details/129599560
版权
该代码实现了一个Linux字符设备驱动，用于在内核空间接收和处理来自用户空间的字符数组和结构体。驱动程序包含了打开、关闭、读写以及ioctl操作，其中ioctl用于控制LED灯的状态和进行数据传递。当接收到结构体时，内核会将结构体内变量加10，然后回传给用户空间。

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需求

  1. 传递字符数组

要求：在内核空间打印字符数组信息内容

#defineUACCESS_BUF_IOW('a',1,char[128])

  1. 传递结构体

要求：将用户空间数据传递给内核空间，在内核空间进行打印，打印之后需要每个变量+10，在传递给用户空间，在用户空间打印增加后的值

头文件：

#ifndef __MYCDEV_H__
#define __MYCDEV_H__

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

#define CNAME "myled"

//GPIOx组控制器结构体
typedef struct {
    volatile unsigned int MODER;   // 0x00
    volatile unsigned int OTYPER;  // 0x04
    volatile unsigned int OSPEEDR; // 0x08
    volatile unsigned int PUPDR;   // 0x0C
    volatile unsigned int IDR;     // 0x10
    volatile unsigned int ODR;     // 0x14
    volatile unsigned int BSRR;    // 0x18
    volatile unsigned int LCKR;    // 0x1C 
    volatile unsigned int AFRL;    // 0x20 
    volatile unsigned int AFRH;    // 0x24
    volatile unsigned int BRR;     // 0x28
    volatile unsigned int res;
    volatile unsigned int SECCFGR; // 0x30
}gpio_t;

int major;
char kbuf[128] = {0};
//初始化rcc、GPIOE、GPIOF组控制器
unsigned int* virt_rcc;
gpio_t* virt_gpioe;
gpio_t* virt_gpiof;
struct class* c;
struct device* d;

//指定GPIOE组基地址
#define  PHY_GPIOE_ADDR  0x50006000
//指定GPIOF组基地址
#define  PHY_GPIOF_ADDR  0x50007000
//RCC基地址：0x50000A28
#define PHY_RCC_LED1 0x50000A28

typedef struct{
    int width;
    int high;
}image_t;

#define LED_ON _IOW('a',1,int)
#define LED_OFF _IOW('a',0,int)
#define UACCESS_BUF _IOW('a',1,char [128])
#define UACCESS_STRUCT _IOW('a',1,image_t)

//LED1亮
#define LED1_ON (virt_gpioe->ODR |= (0x1 << 10))
//LED1灭
#define LED1_OFF (virt_gpioe->ODR &= (~(0x1 << 10)))
//LED2亮
#define LED2_ON (virt_gpiof->ODR |= (0x1 << 10))
//LED2灭
#define LED2_OFF (virt_gpiof->ODR &= (~(0x1 << 10)))
//LED3亮
#define LED3_ON (virt_gpioe->ODR |= (0x1 << 8))
//LED3灭
#define LED3_OFF (virt_gpioe->ODR &= (~(0x1 << 8)))

enum{
    LED1,
    LED2,
    LED3,
    BUF,
    STRUCT,
};

#endif

源文件：

#include "mycdev.h"

image_t L_STR;
image_t U_STR;

int myled_open(struct inode *inode, struct file *file)
{
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}
ssize_t myled_read (struct file *file, char __user *ubuf, size_t size, loff_t *loff)
{
    int ret;
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    if(size > sizeof(kbuf)) size = sizeof(kbuf);
    ret = copy_to_user(&ubuf,&kbuf,size);
    if(!ret)
    {
        printk("copy to user failed\n");
        return -EIO;
    }
    return size;
}

ssize_t myled_write(struct file *file,const char __user *buf,size_t size,loff_t *loff)
{
    int ret;
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    if(size > sizeof(kbuf)) size = sizeof(kbuf);
    ret = copy_from_user(kbuf,buf,size);
    if(ret)
    {
        printk("copy from user failed\n");
        return -EIO;
    }
    //kbuf[0]：1~6，分别控制3盏灯的两个状态
    switch (kbuf[0])
    {
    case '1':
        LED1_ON;
        break;
    case '2':
        LED1_OFF;
        break;
    case '3':
        LED2_ON;
        break;
    case '4':
        LED2_OFF;
        break;
    case '5':
        LED3_ON;
        break;
    case '6':
        LED3_OFF;
        break;
    default:
        printk("Wrong command\n");
        break;
    }
    return size;
}

int myled_close (struct inode *inode, struct file *file)
{
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}

long myled_ioctl(struct file* file,unsigned int cmd,unsigned long args)
{
    //1.判断cmd switch(cmd)
    //2.判断操作那盏灯进行点亮 copy_from_user
    int whitch;
    int ret;
    char buf[128];
    printk("myled_ioctl in\n");
    switch(cmd)
    {
        case LED_ON:
        ret = copy_from_user(&whitch,(void*)args,sizeof(int));
        if(ret)
        {
            printk("copy_from_user failed\n");
            return -EIO;
        }
        printk("cmd in\n");
        printk("cmd = %d , whitch = %d\n",cmd,whitch);
        switch(whitch)
        {
            case LED1:
                printk("LED1 in\n");
                LED1_ON;
                break;
            case LED2:
                LED2_ON;
                break;
            case LED3:
                LED3_ON;
                break;
        }
        break;
        case LED_OFF:
            ret = copy_from_user(&whitch,(void*)args,sizeof(int));
            if(ret)
            {
                printk("copy from user is error\n");
                return -EIO;
            }
            switch(whitch)
            {
                case LED1:
                    LED1_OFF;
                    break;
                case LED2:
                    LED2_OFF;
                    break;
                case LED3:
                    LED3_OFF;
                    break;
            }
            break;
        case UACCESS_BUF:
            ret = copy_from_user(buf,(void*)args,sizeof(buf));
            if(ret)
            {
                printk("copy from user is error\n");
                return -EIO;
            }
            printk("buf in linux = %s\n",buf);
            break;
        case UACCESS_STRUCT:
            ret = copy_from_user(&L_STR,(void*)args,sizeof(L_STR));
            if(ret)
            {
                printk("copy from user is error\n");
                return -EIO;
            }
            printk("STR before driver : STR.high = %d , STR.width = %d\n",L_STR.high,L_STR.width);
            L_STR.high += 10;
            L_STR.width += 10;
            ret = copy_to_user((void*)args,&L_STR,sizeof(L_STR));
            if(ret)
            {
                printk("copy to user is error\n");
                return -EIO;
            }
        }
    return 0;
}

const struct file_operations fops = {
    .open = myled_open,
   // .read = myled_read,
    .write = myled_write,
    .unlocked_ioctl = myled_ioctl,
    .release = myled_close,
};
static int __init mycdev_init(void)
{
    //1.注册字符设备驱动
    major = register_chrdev(0,CNAME,&fops);
    if(major < 0) //2.判断返回值
    {
        printk("register chrdev is error\n");
    }
    //3.打印主设备号
    printk("register chrdev major=%d\n",major);
    c = class_create(THIS_MODULE,"myled");
    if(IS_ERR(c))
    {
        PTR_ERR(c);
    }
    d = device_create(c,NULL,MKDEV(major,0),NULL,"myled");
    if(IS_ERR(d))
    {
        PTR_ERR(d);
    }
    //ioremap(0x5000)
    //4.将物理地址映射为虚拟地址
    //4.1 将rcc地址映射
    virt_rcc = ioremap(PHY_RCC_LED1,4);
    if(virt_rcc == NULL)
    {
        printk("rcc ioremap is error\n");
        return -ENOMEM;
    }
    //4.2 将GPIOE地址映射
    virt_gpioe = ioremap(PHY_GPIOE_ADDR,sizeof(gpio_t));
    if(virt_gpioe == NULL)
    {
        printk("moder ioremap is error\n");
        return -ENOMEM;
    }
    //4.3 将GPIOF地址映射
    virt_gpiof = ioremap(PHY_GPIOF_ADDR,sizeof(gpio_t));
    if(virt_gpiof == NULL)
    {
        printk("odr ioremap is error\n");
        return -ENOMEM;
    }
    //5.对LED1 PE10引脚初始化
    *virt_rcc |= (0x1 << 4);
    virt_gpioe->MODER &= (~(0x3 << 20));
    virt_gpioe->MODER |= (0x1 << 20);
    virt_gpioe->ODR &= (~(0x1) << 10);
    //对LED2 PF10引脚初始化
    *virt_rcc |= (0x1 << 5);
    virt_gpiof->MODER &= (~(0x3 << 20));
    virt_gpiof->MODER |= (0x1 << 20);
    virt_gpiof->ODR &= (~(0x1) << 10);
    //对LED3 PF8引脚初始化
    virt_gpioe->MODER &= (~(0x3 << 16));
    virt_gpioe->MODER |= (0x1 << 16);
    virt_gpioe->ODR &= (~(0x1) << 8);

    return 0;
}
 
static void __exit mycdev_exit(void)
{
    device_destroy(c,MKDEV(major,0));
    class_destroy(c);
    //6.取消地址映射
    iounmap(virt_rcc);
    iounmap(virt_gpioe);
    iounmap(virt_gpiof);
    class_destroy(c);
    //7.注销字符设备驱动
    unregister_chrdev(major,CNAME);
}

module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

//241 myled

测试文件：

#include <sys/ioctl.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>

#define LED_ON _IOW('a',1,int)
#define LED_OFF _IOW('a',0,int)
#define UACCESS_BUF _IOW('a',1,char [128])
#define UACCESS_STRUCT _IOW('a',1,image_t)

enum{
    LED1,
    LED2,
    LED3,
    BUF,
    STRUCT,
};

typedef struct{
    int width;
    int high;
}image_t;

void ioctl_cmd(int fd,int cmd);

int main(int argc,const char * argv[])
{
    char buf[128] = {0};
    int cmd;
    int fd = -1;
    fd = open("/dev/myled",O_RDWR);
    if(fd == -1)
    {
        perror("open is error\n");
        return -1;
    }
    int whitch;
    while (1)
    {
        
        // 循环发送buf[0]：1~6，控制三盏灯循环亮灭
        printf("命令1:*********LED1亮*********\n");
        printf("命令2:*********LED1灭*********\n");
        printf("命令3:*********LED2亮*********\n");
        printf("命令4:*********LED2灭*********\n");
        printf("命令5:*********LED3亮*********\n");
        printf("命令6:*********LED3灭*********\n");
        printf("命令7:*******传递字符串*******\n");
        printf("命令8:*******传递结构体*******\n");
        printf("请输入命令>>>>>>>");
        fgets(buf,sizeof(buf),stdin);
        cmd = buf[0] - '0';
        ioctl_cmd(fd,cmd);
        //system("clear");
    }
    close(fd);
    return 0;
}

void ioctl_cmd(int fd,int cmd)
{
    int whitch;
    char buf[128] = {0};
    switch(cmd)
    {
        case 1:
            whitch = LED1;
            ioctl(fd,LED_ON, &whitch);
            break;
        case 3:
            whitch = LED2;
            ioctl(fd,LED_ON,&whitch);
            break;
        case 5:
            whitch = LED3;
            ioctl(fd,LED_ON,&whitch);
            break;
        case 2:
            whitch = LED1;
            ioctl(fd,LED_OFF,&whitch);
            break;
        case 4:
            whitch = LED2;
            ioctl(fd,LED_OFF,&whitch);
            break;
        case 6:
            whitch = LED3;
            ioctl(fd,LED_OFF,&whitch);
            break;
        case 7:
            whitch = BUF;
            printf("请输入字符串>>>>>>>");
            fgets(buf,sizeof(buf),stdin);
            buf[strlen(buf)-1] = '\0';
            ioctl(fd,UACCESS_BUF,buf);
            break;
        case 8:
            whitch = STRUCT;
            image_t STR = {210,10};
            ioctl(fd,UACCESS_STRUCT,&STR);
            printf("STR after driver : STR.high = %d , STR.width = %d\n",STR.high,STR.width);
            break;
        default:
            printf("Undefined Command\n");
            break;
    }
}

代码结果：

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