156 lines
4.8 KiB
C
156 lines
4.8 KiB
C
/**
|
|
* \defgroup rt Real-time task scheduling
|
|
*
|
|
* The real-time module handles the scheduling and execution of
|
|
* real-time tasks (with predictible execution times).
|
|
*
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* \file
|
|
* Header file for the real-time 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: rt.h,v 1.1 2007/03/19 00:16:13 adamdunkels Exp $
|
|
*/
|
|
#ifndef __RT_H__
|
|
#define __RT_H__
|
|
|
|
typedef unsigned short rt_clock_t;
|
|
#define RT_CLOCK_LT(a,b) ((signed short)((a)-(b)) < 0)
|
|
|
|
/**
|
|
* \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.
|
|
*/
|
|
void rt_init(void);
|
|
|
|
/**
|
|
* \brief Repressentation 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.
|
|
*/
|
|
struct rt_task {
|
|
char *name;
|
|
rt_clock_t time;
|
|
void (* func)(struct rt_task *t, void *ptr);
|
|
unsigned char prio;
|
|
void *ptr;
|
|
};
|
|
|
|
/**
|
|
* \brief Declare a real-time task.
|
|
* \param name The name of the task state variable.
|
|
* \param func The function implementing the real-time task.
|
|
* \param prio The priority of the task.
|
|
* \param ptr An opaque pointer that is passed to the real-time task
|
|
* when it is executed.
|
|
*
|
|
* This macro declares a real-time task.
|
|
*
|
|
* \hideinitializer
|
|
*/
|
|
#define RT_TASK(name, func, prio, ptr) { name, 0, func, prio, ptr }
|
|
|
|
enum {
|
|
RT_OK,
|
|
RT_ERR_FULL,
|
|
RT_ERR_TIME,
|
|
};
|
|
|
|
/**
|
|
* \brief Post a real-time task.
|
|
* \param task A pointer to the task variable previously declared with RT_TASK().
|
|
* \param time The time when the task is to be executed.
|
|
* \return Non-zero (true) if the task could be scheduled, zero
|
|
* (false) if the task could not be scheduled.
|
|
*
|
|
* This function schedules a real-time task a specified
|
|
* time in the future.
|
|
*
|
|
*/
|
|
int rt_post(struct rt_task *task, rt_clock_t time, rt_clock_t duration);
|
|
|
|
/**
|
|
* \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.
|
|
*
|
|
*/
|
|
void rt_task_run(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
|
|
*/
|
|
#define RT_NOW() rt_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
|
|
*/
|
|
#define RT_TASK_TIME(task) ((task)->time)
|
|
|
|
void rt_arch_init(void);
|
|
void rt_arch_schedule(rt_clock_t t);
|
|
rt_clock_t rt_arch_now(void);
|
|
|
|
|
|
#include "rt-arch.h"
|
|
|
|
#endif /* __RT_H__ */
|
|
|
|
/** @} */
|