Linux块设备（3）-模块加载与卸载任务

frensky2

块设备驱动的模块加载与卸载任务：
1分配初始化请求队列， 绑定请求队列和请求函数
2分配初始化gendisk给gendisk的major fops queue等成员赋值，最后添加gendisk;
3注册
加载模板
static int __int xxx_init(void)
{
  xxx_disks = alloc_disk(1);
  if(!xxx_disk)
goto out;
   if(register_blkdev(xxx_MAJOR)
     {
err = -EIO;
goto out;
      }
xxx_queue = blk_alloc_queue(GFP_KERNEL);
if(!xxx_queue)
   goto out_queue;
blk_queue_make_request(xxx_queue, &xxx_make_request);
blk_queue_hardsect(xxx_queue, xxx_blocksize);
  //gendisk初始化
  xxx_disks->major = XXX_MAJOR;
  xxx_disks->first_minor = 0;
  xxx_disks->fops = &xxx_op;
  xxx_disks->queue = xxx_queue;
  sprintf(xxx_disks->disk_name,"xxx%d",i);
  set_capacity(xxx_disks,xxx_size);
  add_disk(xxx_disks);
return 0;
out_queue: unregister_blkdev(XXX_MAJOR, "xxx");
out : put_disk(xxx_disks);
blk_cleanup_queue(xxx_queue);
  return -ENOMEM;
}
static void __exit xxx_exit(void)
{
if(bdev)
{invalidate_bdev(xxx_dev);blkdev_put(xxx_dev);}
del_gendisk(xxx_disks);
put_disk(xxx_disks);
blk_cleanup_queue(xxx_queue);
unregister_blkdev(XXX_MAJOR,"xxx");
}
=====================================
open release 并非必须
static int xxx_open (struct inode *inode, struct file *filp)
{
  struct xxx_dev *dev = inode->i_bdev->bd_disk->private_data;
  filp->private_data = dev;
...
return 0;
}
设置驱动硬件状态 ，分配DMA缓冲区等
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本文来自ChinaUnix博客，如果查看原文请点：http://blog.chinaunix.net/u2/69624/showart_1070876.html