ldd3 驱动－－测试scull

scull驱动模拟设备。编写读写设备的控制文件testscull.c向scull发送和接收数据。

1 安装scull.ko

  在ldd3驱动源码文件夹中，进入scull文件夹，make,生成scull.ko，运行其中的shell文件:scull_load,完成scull.ko的安装。

  # cd /sys/module/scull/parameters/

  #cat scull_major

  253

  #cat scull_minor

  0

  可知scull.ko的主次设备号为253 0

  进入/dev 创建设备文件：

  #cd /dev

  #mknod sculldev c 253 0

2 编写测试文件testscull.c

  代码：

#include
#include
#include
#include
#include
#include
int main()
{
  int fd,len;
  char inbuf[20];
  char outbuf[20]="scull dev test!";
  fd=open("/dev/sculldev",O_WRONLY);
  if(fd<0)
  {printf("Error openning the device of sculldev for wrITing!\n");
  exit(1);
  }
  len=write(fd,outbuf,strlen(outbuf));
  if(len<0)
    { printf("Error writing to the device!\n");
      close(fd);
      exit(1);
   
    }
  printf("writing %d bytes to the device!\n",len);
  close(fd);
  fd=open("/dev/sculldev",O_RDONLY);
  if(fd<0)
  {
    printf("Error openning the device of sculldev for reading!\n");
    exit(1);
  }
  len=read(fd,inbuf,len);
  if(len<0)
    {printf("Error reading from the device!\n ");
     close(fd);
     exit(1);
    }
  printf("reading %d bytes from the device!\n",len);
  printf("%s\n",outbuf);
}

3 测试

#gcc testscull.c -o testscull

#./testscull