contiki/core/sys/rtimer.h

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/** \addtogroup sys
* @{ */
/**
* \defgroup rt Real-time task scheduling
*
* The real-time module handles the scheduling and execution of
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* real-time tasks (with predictable execution times).
*
* @{
*/
/**
* \file
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* Header file for the real-time timer module.
* \author
* Adam Dunkels <adam@sics.se>
*
*/
/*
* Copyright (c) 2005, Swedish Institute of Computer Science
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*
* @(#)$Id: rtimer.h,v 1.11 2010/03/23 13:35:00 fros4943 Exp $
*/
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#ifndef __RTIMER_H__
#define __RTIMER_H__
#include "rtimer-arch.h"
#ifndef RTIMER_CLOCK_LT
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typedef unsigned short rtimer_clock_t;
#define RTIMER_CLOCK_LT(a,b) ((signed short)((a)-(b)) < 0)
#endif /* RTIMER_CLOCK_LT */
/**
* \brief Initialize the real-time scheduler.
*
* This function initializes the real-time scheduler and
* must be called at boot-up, before any other functions
* from the real-time scheduler is called.
*/
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void rtimer_init(void);
struct rtimer;
typedef void (* rtimer_callback_t)(struct rtimer *t, void *ptr);
/**
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* \brief Representation of a real-time task
*
* This structure represents a real-time task and is used
* by the real-time module and the architecture specific
* support module for the real-time module.
*/
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struct rtimer {
rtimer_clock_t time;
rtimer_callback_t func;
void *ptr;
};
enum {
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RTIMER_OK,
RTIMER_ERR_FULL,
RTIMER_ERR_TIME,
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RTIMER_ERR_ALREADY_SCHEDULED,
};
/**
* \brief Post a real-time task.
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* \param task A pointer to the task variable previously declared with RTIMER_TASK().
* \param time The time when the task is to be executed.
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* \param duration Unused argument.
* \param func A function to be called when the task is executed.
* \param ptr An opaque pointer that will be supplied as an argument to the callback function.
* \return Non-zero (true) if the task could be scheduled, zero
* (false) if the task could not be scheduled.
*
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* This function schedules a real-time task at a specified
* time in the future.
*
*/
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int rtimer_set(struct rtimer *task, rtimer_clock_t time,
rtimer_clock_t duration, rtimer_callback_t func, void *ptr);
/**
* \brief Execute the next real-time task and schedule the next task, if any
*
* This function is called by the architecture dependent
* code to execute and schedule the next real-time task.
*
*/
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void rtimer_run_next(void);
/**
* \brief Get the current clock time
* \return The current time
*
* This function returns what the real-time module thinks
* is the current time. The current time is used to set
* the timeouts for real-time tasks.
*
* \hideinitializer
*/
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#define RTIMER_NOW() rtimer_arch_now()
/**
* \brief Get the time that a task last was executed
* \param task The task
* \return The time that a task last was executed
*
* This function returns the time that the task was last
* executed. This typically is used to get a periodic
* execution of a task without clock drift.
*
* \hideinitializer
*/
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#define RTIMER_TIME(task) ((task)->time)
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void rtimer_arch_init(void);
void rtimer_arch_schedule(rtimer_clock_t t);
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/*rtimer_clock_t rtimer_arch_now(void);*/
#define RTIMER_SECOND RTIMER_ARCH_SECOND
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#endif /* __RTIMER_H__ */
/** @} */
/** @} */