测试代码实现 memdev.h #ifndef _MEMDEV_H_ #define _MEMDEV_H_ #include<linux/ioctl.h> #ifndef MEMDEV_MAJOR #define MEMDEV_MAJOR 0 #endif #ifndef MEMDEV_NR_DEVS #define MEMDEV_NR_DEVS 2 #endif #ifndef MEMDEV_SIZE #define MEMDEV_SIZE 4096 #endif struct mem_dev { char *data; unsigned long size; }; #define MEMDEV_IOC_MAGIC 'k' #define MEMDEV_IOCPRINT _IO(MEMDEV_IOC_MAGIC,0) #define MEMDEV_IOCGETDATA _IOR(MEMDEV_IOC_MAGIC,1,int) #define MEMDEV_IOC_MAXNR 3 #endif memdev.c #include<linux/module.h> #include<linux/kernel.h> #include<linux/types.h> #include<linux/fs.h> #include<linux/errno.h> #include<linux/mm.h> #include<linux/sched.h> #include<linux/init.h> #include<linux/cdev.h> #include<linux/slab.h> #include<asm/io.h> #include<asm/system.h> #include<asm/uaccess.h> #include "memdev.h" static int mem_major = MEMDEV_MAJOR; module_param(mem_major,int,S_IRUGO); struct mem_dev *mem_devp; struct cdev cdev; int mem_open(struct inode *inode,struct file *filp) { struct mem_dev *dev; int num = MINOR(inode->i_rdev); if(num >= MEMDEV_NR_DEVS) return -ENODEV; dev = &mem_devp[num]; filp->private_data = dev; return 0; } int mem_release(struct inode *inode,struct file *filp) { return 0; } long memdev_ioctl(struct file *filp,unsigned int cmd,unsigned long arg) { int err = 0; int ret = 0; int ioarg = 0; printk("kernel cmd is : %ld ",cmd); switch(cmd) { case MEMDEV_IOCPRINT: printk("CMD MEMDEV_IOCPRINT DONE "); break; case MEMDEV_IOCGETDATA: ioarg = 1101; if(copy_to_user((int *)arg,&ioarg,sizeof(int))) return -EFAULT; break; default: return -EINVAL; } return ret; } static const struct file_operations mem_fops = { .owner = THIS_MODULE, .open = mem_open, .release = mem_release, .unlocked_ioctl = memdev_ioctl, }; static int memdev_init(void) { int result; int i; dev_t devno = MKDEV(mem_major,0); if (mem_major) { result = register_chrdev_region(devno,2,"memdev"); printk("first mem_major is : %ld ",mem_major); } else { result = alloc_chrdev_region(&devno,0,2,"memdev"); mem_major = MAJOR(devno); printk("second mem_major is : %ld ",mem_major); } if(result < 0) return result; cdev_init(&cdev,&mem_fops); cdev.owner = THIS_MODULE; cdev.ops = &mem_fops; cdev_add(&cdev,MKDEV(mem_major,0),MEMDEV_NR_DEVS); mem_devp = kmalloc(MEMDEV_NR_DEVS * sizeof(struct mem_dev),GFP_KERNEL); if(!mem_devp) { result = -ENOMEM; goto fail_malloc; } memset(mem_devp,0,sizeof(struct mem_dev)); for(i=0;i<MEMDEV_NR_DEVS;i++) { mem_devp[i].size = MEMDEV_SIZE; mem_devp[i].data = kmalloc(MEMDEV_SIZE,GFP_KERNEL); memset(mem_devp[i].data,0,MEMDEV_SIZE); } return 0; fail_malloc: unregister_chrdev_region(devno,1); return result; } static void memdev_exit(void) { cdev_del(&cdev); kfree(mem_devp); unregister_chrdev_region(MKDEV(mem_major,0),2); } MODULE_LICENSE("GPL"); module_init(memdev_init); module_exit(memdev_exit); Makefile obj-m += memdev.o CURRENT_PATH := $(shell pwd) LINUX_KERNEL := $(shell uname -r) LINUX_KERNEL_PATH := /usr/src/linux-headers-$(LINUX_KERNEL) all: make -C $(LINUX_KERNEL_PATH) M=$(CURRENT_PATH) modules clean: make -C $(LINUX_KERNEL_PATH) M=$(CURRENT_PATH) clean app-ioctl.c #include<stdio.h> #include<sys/types.h> #include<sys/stat.h> #include<fcntl.h> #include "memdev.h" int main(void) { int fd = 0; int cmd; int arg = 0; char Buf[4096]; fd = open("/dev/memdev0",O_RDWR); if(fd < 0) { printf("Open Dev Mem Erro "); return -1; } printf("call memdev_iocprint "); cmd = MEMDEV_IOCPRINT; printf("userspace cmd is : %ld ",cmd); if(ioctl(fd,cmd,&arg) < 0) { printf("call cmd MEMDEV_IOCPRINT fail "); return -1; } printf("call MEMDEV_IOCGETDATA "); cmd = MEMDEV_IOCGETDATA; if(ioctl(fd,cmd,&arg) < 0) { printf("call cmd MEMDEV_IOCGETDATA fail "); return -1; } printf("in user space MEMDEV_IOCGETDATA get data is %d ",arg); close(fd); return 0; }
编译memdev，对应的设备驱动
make
insmod memdev.ko
在dmesg中会有输出结果init，在/proc/devices中生成对应的设备驱动号249
创建设备节点
cat /proc/devices中生成的memdev节点编号249
mknod /dev/memdev0 c 249 0创建设备节点，并将对应的设备节点与设备驱动号进行绑定。当打开该设备节点进行后续操作时，将会由设备驱动文件进行具体实现
编译app ioctl测试文件
gcc -o app-ioctl app-ioctl.c
./app-ioctl
正常执行结果会显示，dmesg也会显示内核结果