驱动 10月23日 作业

通过字符设备驱动的分步实现编写LED驱动，另外实现设备文件和设备的绑定

test.c

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include "head.h"
 
int main(int argc, char const *argv[])
{
    char buf[128];
    int a;
    char b[10];
    //char str[100] = "/dev/mycdev0";
    // printf("0(led1) 1(led2) 2(led3)\n");
    
    while (1)
    {
        strcpy(buf, "/dev/mychrdev");
        printf("0(led1) 1(led2) 2(led3)\n");
        scanf("%s", b);
        strcat(buf, b);
        //printf("%s\n", str);
        int fd = open(buf, O_RDWR);
        printf("%d\n", fd);
 
        if (fd < 0)
        {
            printf("打开设备文件失败\n");
            exit(-1);
        }
        printf("打开设备文件成功\n");
 
        //从终端读取
        printf("请输入要实现的功能\n");
        printf("0（关灯）1（开灯）\n");
        printf("请输入> ");
        scanf("%d", &a);
        switch (a)
        {
        case 1:
            ioctl(fd, LED_ON);
            break;
        
        case 0:
            ioctl(fd, LED_OFF);
            break;
        }
        //write(fd, buf, sizeof(buf));//将数据传递给内核
        // memset(buf, 0, sizeof(buf));//清空数组
        // read(fd, buf, sizeof(buf));//将内核空间数据传递到用户
        // printf("buf:%s\n", buf);
        close(fd);
 
        bzero(buf, sizeof(buf));
    }
    
    return 0;
}

mycdev.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include "head.h"
 
struct cdev *cdev;
unsigned int major = 0;
unsigned int minor = 0;
struct class *cls;
dev_t devno;
struct device *dev;
 
// 定义三个灯指针指向映射后的虚拟内存
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;
 
// 封装操作方法
int mycdev_open(struct inode *inode, struct file *file)
{
    int min = MINOR(inode->i_rdev); //获取打开的文件的次设备号
    file->private_data = (void *)min;
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}
 
long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    int min = (int)file->private_data; //获取到文件的次设备号
    switch (min)
    {
    case 0: //操作LED1
        switch (cmd)
        {
        case LED_ON: //开灯
            vir_led1->ODR |= (0x1 << 10);
            break;
        
        case LED_OFF: //关灯
            vir_led1->ODR &= (~(0x1 << 10));
            break;
        }
        break;
    
    case 1: //操作LED2
        switch (cmd)
        {
        case LED_ON: //开灯
            vir_led2->ODR |= (0x1 << 10);
            break;
        
        case LED_OFF: //关灯
            vir_led2->ODR &= (~(0x1 << 10));
            break;
        }
        break;
 
    case 2: //操作LED3
        switch (cmd)
        {
        case LED_ON: //开灯
            vir_led3->ODR |= (0x1 << 8);
            break;
        
        case LED_OFF: //关灯
            vir_led3->ODR &= (~(0x1 << 8));
            break;
        }
        break;
    }
 
    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,
    .unlocked_ioctl = mycdev_ioctl,
    .release = mycdev_close,
};
 
int all_led_init(void)
{
    // 进行寄存器的地址映射
    vir_led1 = ioremap(PHY_LED1_ADDR, sizeof(gpio_t));
    if (vir_led1 == NULL)
    {
        printk("物理内存地址映射失败 %d\n", __LINE__);
        return -ENOMEM;
    }
 
    vir_led2 = ioremap(PHY_LED2_ADDR, sizeof(gpio_t));
    if (vir_led1 == NULL)
    {
        printk("物理内存地址映射失败 %d\n", __LINE__);
        return -ENOMEM;
    }
 
    vir_led3 = ioremap(PHY_LED3_ADDR, sizeof(gpio_t));
    if (vir_led1 == NULL)
    {
        printk("物理内存地址映射失败 %d\n", __LINE__);
        return -ENOMEM;
    }
 
    vir_rcc = ioremap(PHY_RCC_ADDR, 4);
    if (vir_rcc == NULL)
    {
        printk("物理内存地址映射失败 %d\n", __LINE__);
        return -ENOMEM;
    }
    printk("物理地址映射成功\n");
 
    (*vir_rcc) |= (0x3 << 4); // GPIOE、F控制器时钟使能
 
    // LED1寄存器初始化
    vir_led1->MODER &= (~(0x3 << 20)); // MODER[21:20] -> 20
    vir_led1->MODER |= (0x1 << 20);    // MODER[21:20] -> 01
    vir_led1->ODR &= (~(0x1 << 10));   // 默认关灯
 
    // LED2寄存器初始化
    vir_led2->MODER &= (~(0x3 << 20)); // MODER[21:20] -> 20
    vir_led2->MODER |= (0x1 << 20);    // MODER[21:20] -> 01
    vir_led2->ODR &= (~(0x1 << 10));   // 默认关灯
 
    // LED3寄存器初始化
    vir_led3->MODER &= (~(0x3 << 16)); // MODER[21:20] -> 20
    vir_led3->MODER |= (0x1 << 16);    // MODER[21:20] -> 01
    vir_led3->ODR &= (~(0x1 << 8));    // 默认关灯
    printk("寄存器初始化成功\n");
 
    return 0;
}
 
// 入口函数，安装内核模块时执行
static int __init mycdev_init(void)
{
    int ret, i;
    //1.申请一个对象空间cdev_alloc
    cdev = cdev_alloc();
    if (cdev == NULL)
    {
        printk("申请字符设备驱动对象失败 %d \n", __LINE__);
        ret = -EFAULT; 
        goto out1;
    }
    printk("字符设备驱动对象申请成功\n");
 
    //2.初始化对象cdev_init
    cdev_init(cdev, &fops);
    
    //3.申请设备号 register_chrdev_region()/alloc_chrdev_region()
    if (major == 0) //动态申请
    {
        ret = alloc_chrdev_region(&devno, minor, 3, "mychrdev");
        if (ret)
        {
            printk("动态申请设备号失败 %d\n", __LINE__);
            goto out2;
        }
        major = MAJOR(devno); //根据设备号获取主设备号
        minor = MINOR(devno); //根据设备号获取次设备号
    }
    else
    {
        ret = register_chrdev_region(MKDEV(major, minor), 3, "mychrdev");
        if (ret)
        {
            printk("静态指定设备号失败\n");
            goto out2;
        }
    }
    printk("设备号申请成功\n");
    
    //4.注册驱动对象 cdev_add
    ret = cdev_add(cdev, MKDEV(major, minor), 3);
    if (ret != 0)
    {
        printk("注册字符设备驱动对象失败 %d\n", __LINE__);
        goto out3;
    }
    printk("注册字符设备驱动对象成功\n");
 
    //5.向上提交目录 class_create
    cls = class_create(THIS_MODULE, "mychrdev");
    if (IS_ERR(cls))
    {
        printk("向上提交目录失败 %d\n", __LINE__);
        goto out4;
    }
    printk("向上提交目录成功\n");
 
    //6.向上提交设备节点信息 device_create
    for (i = 0; i < 3; i++)
    {
        dev = device_create(cls, NULL, MKDEV(major, i), NULL, "mychrdev%d", i);
        if (IS_ERR(dev))
        {
            printk("向上提交设备节点失败 %d\n", __LINE__);
            goto out5;
        }
    }
    printk("向上提交设备节点成功\n");
 
    all_led_init();
 
    return 0;
 
out5:
    //将提交成功的节点信息释放
    for(--i; i >= 0; i--)
    {
        device_destroy(cls, MKDEV(major, i));
    }
 
    //销毁目录
    class_destroy(cls);
 
out4:
    cdev_del(cdev);
 
out3:
    unregister_chrdev_region(MKDEV(major, minor), 3);
 
out2:
    kfree(cdev);
 
out1:
    return ret;
}
 
// 出口函数，卸载内核模块时执行
static void __exit mycdev_exit(void)
{
    //取消地址映射
    iounmap(vir_led1);
    iounmap(vir_led2);
    iounmap(vir_rcc);
 
    //1.销毁设备节点信息
    int i;
    for (i = 0; i < 3; i++)
    {
        device_destroy(cls, MKDEV(major, i));
    }
    
    //2.销毁目录
    class_destroy(cls);
 
    //3.注销字符设备驱动对象
    cdev_del(cdev);
 
    //4.释放设备号
    unregister_chrdev_region(MKDEV(major, minor), 3);
 
    //5.释放申请到的字符设备驱动对象空间
    kfree(cdev);
}
 
// 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");