ARM-驱动/Day2

编写三盏灯控制的驱动，应用程序编写三盏灯亮灭的逻辑

mycdev.c

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

unsigned int major;
char kbuf[128]={0};
//定义三个指针指向映射后的虚拟内存首地址
unsigned int *vir_rcc;
unsigned int *vir1_moder;
unsigned int *vir1_odr;

unsigned int *vir2_moder;
unsigned int *vir2_odr;

unsigned int *vir3_moder;
unsigned int *vir3_odr;

 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)
{
    int ret;
    if(size>sizeof(kbuf))
        size=sizeof(kbuf);
    ret=copy_to_user(ubuf,kbuf,size);
    if(ret=0)
    {
        printk("copy from user filed\n");
        return -EIO;
    }
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}
ssize_t mycdev_write (struct file *file, const char *ubuf, size_t size, loff_t *lof)
{
    int ret;
    if(size>sizeof(kbuf))
        size=sizeof(kbuf);
    ret=copy_from_user(kbuf,ubuf,size);
    if(ret=0)
    {
        printk("copy from user filed\n");
        return -EIO;
    }
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    
    //LED1
    if(strcmp(kbuf,"LED1_ON")==0)
        (*vir1_odr)|=(0x1<<10);
    else if(!strcmp(kbuf,"LED1_OFF"))
        (*vir1_odr)&=(~(0x1<<10));
    //LED2
    if(strcmp(kbuf,"LED2_ON")==0)
         (*vir2_odr)|=(0x1<<10);
    else if(!strcmp(kbuf,"LED2_OFF"))
        (*vir2_odr)&=(~(0x1<<10));
    //LED3
    if(strcmp(kbuf,"LED3_ON")==0)
        (*vir3_odr)|=(0x1<<8);
    else if(!strcmp(kbuf,"LED3_OFF"))
        (*vir3_odr)&=(~(0x1<<8));
    return 0;
}
int mycdev_close (struct inode *inode, struct file *file)
{
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}

//定义一个操作方法结构体变量并且初始化
//将上面封装的各个操作方法赋值给结构体变量成员
struct file_operations fops={
    .open=mycdev_open,
    .read=mycdev_read,
    .write=mycdev_write,
    .release=mycdev_close,
};

//1.入口
static int __init mycdev_init(void)
{
    major=register_chrdev(0,"mycdev",&fops);
    if(major<0)
    {
        printk("字符设备创建失败\n");
        return major;
    }
    printk("字符设备注册成功,major=%d\n",major);
    //进行LED相关寄存器地址映射
    vir_rcc=ioremap(LED_RCC,4);
    if(vir_rcc==NULL)
    {
        printk("物理内存映射失败\n");
        return -EFAULT;
    }
    vir1_moder=ioremap(LED1_MODER,4);
    vir1_odr=ioremap(LED1_ODR,4);

    vir2_moder=ioremap(LED2_MODER,4);
    vir2_odr=ioremap(LED2_ODR,4);

    vir3_moder=ioremap(LED3_MODER,4);
    vir3_odr=ioremap(LED3_ODR,4);
   
    //相关寄存器初始化
    //LED1---->PE10
    (*vir_rcc) |=(0x1<<4);
    (*vir1_moder)&=(~(0x3<<20));
    (*vir1_moder)|=(0x1<<20);
    (*vir1_odr)&=(~(0x1<<10));
    //LED2---->PF10
    (*vir_rcc) |=(0x1<<5);
    (*vir2_moder)&=(~(0x3<<20));
    (*vir2_moder)|=(0x1<<20);
    (*vir2_odr)&=(~(0x1<<10));
    //LED3---->PE8
    (*vir3_moder)&=(~(0x3<<16));
    (*vir3_moder)|=(0x1<<16);
    (*vir3_odr)&=(~(0x1<<8));
    printk("相关寄存器初始化成功\n");
    return 0;
}

//2.出口
static void __exit mycdev_exit(void)
{
    iounmap(vir_rcc);
    iounmap(vir1_moder);
    iounmap(vir1_odr);

    iounmap(vir2_moder);
    iounmap(vir2_odr);

    iounmap(vir3_moder);
    iounmap(vir3_odr);
    unregister_chrdev(major,"mycdev");
}
module_init(mycdev_init);
//module_init是内核提供的宏
//告诉内核驱动的入口函数的地址
module_exit(mycdev_exit);
//告诉内核驱动的出口函数的地址
//3.许可证
MODULE_LICENSE("GPL"); //遵从开源协议

led.h

#ifndef __LED_H__
#define __LED_H__

//LED1---> PE10  GPIOE--> 0x50006000 
#define LED_RCC    0x50000A28
#define LED1_MODER  0x50006000
#define LED1_ODR    0x50006014

//LED2---> PF10  GPIOF--> 0x50007000
//#define LED2_RCC   0x50000A28
#define LED2_MODER 0x50007000
#define LED2_ODR   0x50007014

//LED3---> PE8   GPIOE--> 0x50006000
//#define LED3_RCC    0x50000A28
#define LED3_MODER  0x50006000
#define LED3_ODR    0x50006014

#endif

test.c

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include<string.h>
#include "led.h"

int main(int argc,const char * argv[])
{
    char buf[128]={0};
    int fd=open("/dev/mycdev",O_RDWR);
    if(fd<0)
    {
        printf("设备文件打开失败\n");
        exit(-1);
    }
    while(1)
    {
        memset(buf,0,sizeof(buf));
        printf("请输入控制码:LED%d_ON: LED%d_OFF>>");
        fgets(buf,sizeof(buf),stdin); //从终端获取
        buf[strlen(buf)-1]='\0';
        write(fd,buf,sizeof(buf));
        //memset(buf,0,sizeof(buf));
        //read(fd,buf,sizeof(buf));
        //printf("buf:%s\n",buf);
    }
    return 0;
}

Makefile

arch ?=arm
modname ?=demo

ifeq ($(arch),arm)
#KERNELDIR:指向内核目录的一个变量
	KERNELDIR:= /home/ubuntu/linux-5.10.61               #开发板上可安装的arm格式

else
	KERNELDIR := /lib/modules/$(shell uname -r)/build/   #ubuntu可以安装的x86-64格式
endif

PWD :=$(shell pwd)
#当前路径$(shell pwd)在Makefile的时候起一个终端
#这个终端上执行pwd，将这个命令的结果赋值给PWD变量

all:
	make -C $(KERNELDIR) M=$(PWD) modules
#make -C $(KERNELDIR)
#进入到内核顶层目录下，读取这个目录下的Makefile文件，然后执行make
# M=$(PWD) ：指定编译模块的路径为当前路径
# make modules 模块化编译
#进入内核顶层目录下读取Makefile文件，然后进行模块化编译
#通过M指定编译的目录在当前目录
clean:
	make -C $(KERNELDIR) M=$(PWD) clean
#清除编译

obj-m:=$(modname).o
#指定编译的当前目录的的模块名是$(modname)===>$(modname).ko

测试：

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