基于Ubuntu16.04 的globalmem驱动测试

基于Ubuntu16.04 的globalmem驱动测试

• 网上大多数都是基于2.6的内核，自己懒得替换内核，基于最新内核需要做一些修改。代码参考基本来自网上，自己做一个综合。

一.首先检查当前内核版本

---

二，安装驱动

1.实验代码

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
//高版本替换 system.h
#include 
#include 
增加此头文件//
#include 

#define GLOBALMEM_SIZE  0x1000  /*全局内存最大4K字节*/
#define MEM_CLEAR 0x1  /*清0全局内存*/
#define GLOBALMEM_MAJOR 666    /*预设的globalmem的主设备号*/
static int globalmem_major = GLOBALMEM_MAJOR;
/*globalmem设备结构体*/
struct globalmem_dev                                     
{                                                        
  struct cdev cdev; /*cdev结构体*/                       
  unsigned char mem[GLOBALMEM_SIZE]; /*全局内存*/        
};

struct globalmem_dev *globalmem_devp; /*设备结构体指针*/
/*文件打开函数*/
int globalmem_open(struct inode *inode, struct file *filp)
{
  /*将设备结构体指针赋值给文件私有数据指针*/
  filp->private_data = globalmem_devp;
  return 0;
}
/*文件释放函数*/
int globalmem_release(struct inode *inode, struct file *filp)
{
  return 0;
}

/* ioctl设备控制函数 */
static int globalmem_ioctl(struct inode *inodep, struct file *filp, unsigned
  int cmd, unsigned long arg)
{
  struct globalmem_dev *dev = filp->private_data;/*获得设备结构体指针*/

  switch (cmd)
  {
    case MEM_CLEAR:
      memset(dev->mem, 0, GLOBALMEM_SIZE);      
      printk(KERN_INFO "globalmem is set to zero/n");
      break;

    default:
      return  - EINVAL;
  }
  return 0;
}

/*读函数*/
static ssize_t globalmem_read(struct file *filp, char __user *buf, size_t size,
  loff_t *ppos)
{
  unsigned long p =  *ppos;
  unsigned int count = size;
  int ret = 0;
  struct globalmem_dev *dev = filp->private_data; /*获得设备结构体指针*/

  /*分析和获取有效的写长度*/
  if (p > GLOBALMEM_SIZE)
    return count ?  - ENXIO: 0;
  if (count > GLOBALMEM_SIZE - p)
    count = GLOBALMEM_SIZE - p;

  /*内核空间->用户空间*/
  if (copy_to_user(buf, (void*)(dev->mem + p), count))
  {
    ret =  - EFAULT;
  }
  else
  {
    *ppos += count;
    ret = count;

    printk(KERN_INFO "read %d bytes(s) from %d/n", count, p);
  }

  return ret;
}

/*写函数*/
static ssize_t globalmem_write(struct file *filp, const char __user *buf,
  size_t size, loff_t *ppos)
{
  unsigned long p =  *ppos;
  unsigned int count = size;
  int ret = 0;
  struct globalmem_dev *dev = filp->private_data; /*获得设备结构体指针*/

  /*分析和获取有效的写长度*/
  if (p > GLOBALMEM_SIZE)
    return count ?  - ENXIO: 0;
  if (count > GLOBALMEM_SIZE - p)
    count = GLOBALMEM_SIZE - p;

  /*用户空间->内核空间*/
  if (copy_from_user(dev->mem + p, buf, count))
    ret =  - EFAULT;
  else
  {
    *ppos += count;
    ret = count;

    printk(KERN_INFO "written %d bytes(s) from %d/n", count, p);
  }

  return ret;
}

/* seek文件定位函数 */
static loff_t globalmem_llseek(struct file *filp, loff_t offset, int orig)
{
  loff_t ret = 0;
  switch (orig)
  {
    case 0:   /*相对文件开始位置偏移*/
      if (offset < 0)
      {
        ret =  - EINVAL;
        break;
      }
      if ((unsigned int)offset > GLOBALMEM_SIZE)
      {
        ret =  - EINVAL;
        break;
      }
      filp->f_pos = (unsigned int)offset;
      ret = filp->f_pos;
      break;
    case 1:   /*相对文件当前位置偏移*/
      if ((filp->f_pos + offset) > GLOBALMEM_SIZE)
      {
        ret =  - EINVAL;
        break;
      }
      if ((filp->f_pos + offset) < 0)
      {
        ret =  - EINVAL;
        break;
      }
      filp->f_pos += offset;
      ret = filp->f_pos;
      break;
    default:
      ret =  - EINVAL;
      break;
  }
  return ret;
}

/*文件操作结构体*/
static const struct file_operations globalmem_fops =
{
  .owner = THIS_MODULE,
  .llseek = globalmem_llseek,
  .read = globalmem_read,
  .write = globalmem_write,
  //.ioctl 改为 .compat_ioctl
  .compat_ioctl = globalmem_ioctl,
  .open = globalmem_open,
  .release = globalmem_release,
};

/*初始化并注册cdev*/
static void globalmem_setup_cdev(struct globalmem_dev *dev, int index)
{
  int err, devno = MKDEV(globalmem_major, index);

  cdev_init(&dev->cdev, &globalmem_fops);
  dev->cdev.owner = THIS_MODULE;
  dev->cdev.ops = &globalmem_fops;
  err = cdev_add(&dev->cdev, devno, 1);
  if (err)
    printk(KERN_NOTICE "Error %d adding LED%d", err, index);
}

/*设备驱动模块加载函数*/
int globalmem_init(void)
{
  int result;
  dev_t devno = MKDEV(globalmem_major, 0);

  /* 申请设备号*/
  if (globalmem_major)
    result = register_chrdev_region(devno, 1, "globalmem");
  else  /* 动态申请设备号 */
  {
    result = alloc_chrdev_region(&devno, 0, 1, "globalmem");
    globalmem_major = MAJOR(devno);
  }  
  if (result < 0)
    return result;

  /* 动态申请设备结构体的内存*/
  globalmem_devp = kmalloc(sizeof(struct globalmem_dev), GFP_KERNEL);
  if (!globalmem_devp)    /*申请失败*/
  {
    result =  - ENOMEM;
    goto fail_malloc;
  }
  memset(globalmem_devp, 0, sizeof(struct globalmem_dev));

  globalmem_setup_cdev(globalmem_devp, 0);
  return 0;

  fail_malloc: unregister_chrdev_region(devno, 1);
  return result;
}

/*模块卸载函数*/
void globalmem_exit(void)
{
  cdev_del(&globalmem_devp->cdev);   /*注销cdev*/
  kfree(globalmem_devp);     /*释放设备结构体内存*/
  unregister_chrdev_region(MKDEV(globalmem_major, 0), 1); /*释放设备号*/
}

MODULE_AUTHOR("CK OS test");
MODULE_LICENSE("Dual BSD/GPL");

module_param(globalmem_major, int, S_IRUGO);

module_init(globalmem_init);
module_exit(globalmem_exit);

2.Makefile

ifneq ($(KERNELRELEASE),) 
obj-m:= globalmem.o     
else 
    KERNELDIR =/lib/modules/$(shell uname -r)/build 
    PWD := $(shell pwd) 
default: 
    $(MAKE) -C $(KERNELDIR) M=$(PWD) modules
clean:
    rm ‐rf *.o *~ core .depend .*.cmd *.ko *.mod.c   
endif 

• 执行make
• sudo insmod globalmem.ko
• 若插入错误 insmod: can’t insert ‘memdev.ko’: Device or resource busy
  检查设备号是否被占用自己重新编译一下。
• cat /proc/devices 是否有已经用了 GLOBALMEM_MAJOR

3.创建设备节点

• sudo mknode /dev/globalmem c 666 0
• 修改读写权限
• sudo chmod 666 /dev/globalmem

4.设备测试

三，驱动测试

实验代码

#include
#include
#include
#include
#include
main()
{
    char str[1024],str2[1024];
    int fd,stop;
    int ret;
    fd=open("/dev/globalmem",O_RDWR,S_IRUSR|S_IWUSR);
    printf("Dev number %d\n",fd);
    if(fd != -1)
    {
        printf("Please input the string written to globalmem:\n");
        scanf("%s",str);
        printf("The str is %s\n",str);
        ioctl(fd,1,NULL);
        ret=write(fd,str,strlen(str));
        printf("The ret is %d\n",ret);
        lseek(fd,0,SEEK_SET);
        scanf("%d",&stop);
        read(fd,str2,100);
        printf(" The globalmem is %s\n",str2);
        close(fd);
    }else{
        printf("Device open failure\n");
    }
}

运行截图

四.总结

• 内核编译替换需要注意
• 驱动文件里的相关函数要对应相应的内核版本
• 编译的时候，注意makefile文件，设计环境依赖和链接
• 插入模块的时候，注意插入权限，设备号是否重复，读写权限

资源全打包

http://download.csdn.net/download/qq_33728573/10158398