completion.c

/*
 * File      : completion.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2012, RT-Thread Development Team
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rt-thread.org/license/LICENSE
 *
 * Change Logs:
 * Date           Author       Notes
 * 2012-09-30     Bernard      first version.
 */

#include <rthw.h>
#include <rtthread.h>
#include <rtdevice.h>

#define RT_COMPLETED	1
#define RT_UNCOMPLETED	0

void rt_completion_init(struct rt_completion* completion)
{
	rt_base_t level;
	RT_ASSERT(completion != RT_NULL);

	level = rt_hw_interrupt_disable();
	completion->flag = RT_UNCOMPLETED;
	rt_list_init(&completion->suspended_list);
	rt_hw_interrupt_enable(level);
}

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;
}

void rt_completion_done(struct rt_completion* completion)
{
	rt_base_t level;
	RT_ASSERT(completion != RT_NULL);

	level = rt_hw_interrupt_disable();
	completion->flag = RT_COMPLETED;

	if (!rt_list_isempty(&(completion->suspended_list)))
	{
		/* there is one thread in suspended list */
		struct rt_thread *thread;

		/* get thread entry */
		thread = rt_list_entry(completion->suspended_list.next, struct rt_thread, tlist);
		
		/* resume it */
		rt_thread_resume(thread);
		rt_hw_interrupt_enable(level);

		/* perform a schedule */
		rt_schedule();
	}
	else
	{
		rt_hw_interrupt_enable(level);
	}
}