2.1.0版本UART发送完成，和dma用到的queue和rt_completion_init问题

发布于 2017-08-11 15:49:03 浏览：3489 订阅该版

8 个回答

bernard 2017-08-11

这家伙很懒，什么也没写！

qq_哎 2017-08-11

这家伙很懒，什么也没写！

>rt_completion_wait --> 等待一个工作结束；
rt_completion_done --> 通知这个工作已经完成了；

```c
rt_err_t rt_completion_wait(struct rt_completion *completion,
rt_int32_t timeout)
{
rt_err_t result;
rt_base_t level;
rt_thread_t thread;
RT_ASSERT(completion != RT_NULL);

result = RT_EOK;
thread = rt_thread_self();

level = rt_hw_interrupt_disable();
if (completion->flag != RT_COMPLETED)
{
/* only one thread can suspend on complete */
RT_ASSERT(rt_list_isempty(&(completion->suspended_list)));

if (timeout == 0)
{
result = -RT_ETIMEOUT;
goto __exit;
}
else
{
/* reset thread error number */
thread->error = RT_EOK;

/* suspend thread */
rt_thread_suspend(thread);
/* add to suspended list */
rt_list_insert_before(&(completion->suspended_list),
&(thread->tlist));

/* current context checking */
RT_DEBUG_NOT_IN_INTERRUPT;

/* start timer */
if (timeout > 0)
{
/* reset the timeout of thread timer and start it */
rt_timer_control(&(thread->thread_timer),
RT_TIMER_CTRL_SET_TIME,
&timeout);
rt_timer_start(&(thread->thread_timer));
}
/* enable interrupt */
rt_hw_interrupt_enable(level);

/* do schedule */
rt_schedule();

/* thread is waked up */
result = thread->error;

level = rt_hw_interrupt_disable();
}
}
/* clean completed flag */
completion->flag = RT_UNCOMPLETED;

__exit:
rt_hw_interrupt_enable(level);

return result;
}。
```

看了下函数源码，挂起当前线程，然后放入到挂起链表中，然后开起定时器，再调度。。
还是不太明白这样的话是在等待什么完成呢？还有完成的时候是从挂起链表中取出，然后恢复线程。这个到底是怎么通知？
我觉得这种等待完成，可以是用一个事件来做，超时了返回错误，没超时就正确。

bernard 2017-08-11

这家伙很懒，什么也没写！

qq_哎 2017-08-11

这家伙很懒，什么也没写！

```c
rt_err_t rt_completion_wait(struct rt_completion *completion,
rt_int32_t timeout)
{
rt_err_t result;
rt_base_t level;
rt_thread_t thread;
RT_ASSERT(completion != RT_NULL);

result = RT_EOK;
thread = rt_thread_self();

level = rt_hw_interrupt_disable();
if (completion->flag != RT_COMPLETED)
{
/* only one thread can suspend on complete */
RT_ASSERT(rt_list_isempty(&(completion->suspended_list)));

if (timeout == 0)
{
result = -RT_ETIMEOUT;
goto __exit;
}
else
{
/* reset thread error number */
thread->error = RT_EOK;

/* suspend thread */
rt_thread_suspend(thread);
/* add to suspended list */
rt_list_insert_before(&(completion->suspended_list),
&(thread->tlist));

/* current context checking */
RT_DEBUG_NOT_IN_INTERRUPT;

/* do schedule */
rt_schedule();

/* thread is waked up */
result = thread->error;

level = rt_hw_interrupt_disable();
}
}
/* clean completed flag */
completion->flag = RT_UNCOMPLETED;

__exit:
rt_hw_interrupt_enable(level);

return result;
}。
```

呃，才学会加格式，，，，