369 lines
10 KiB
C
369 lines
10 KiB
C
/*
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* Copyright (c) 2004, Swedish Institute of Computer Science.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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* Author: Adam Dunkels <adam@sics.se>
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*
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* $Id: mt.h,v 1.3 2006/09/26 20:59:51 adamdunkels Exp $
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*/
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/** \addtogroup sys
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* @{
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*/
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/**
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* \defgroup mt Multi-threading library
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*
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* The event driven Contiki kernel does not provide multi-threading
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* by itself - instead, preemptive multi-threading is implemented
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* as a library that optionally can be linked with applications. This
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* library constists of two parts: a platform independent part, which is
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* the same for all platforms on which Contiki runs, and a platform
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* specific part, which must be implemented specifically for the
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* platform that the multi-threading library should run.
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*
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* @{
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*/
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/**
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* \defgroup mtarch Architecture support for multi-threading
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* @{
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*
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* The Contiki multi-threading library requires some architecture
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* specific support for seting up and switching stacks. This support
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* requires three stack manipulation functions to be implemented:
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* mtarch_start(), which sets up the stack frame for a new thread,
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* mtarch_exec(), which switches in the stack of a thread, and
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* mtarch_yield(), which restores the kernel stack from a thread's
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* stack. Additionally, two functions for controlling the preemption
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* (if any) must be implemented: mtarch_preemption_start() and
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* mtarch_preemption_stop(). If no preemption is used, these functions
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* can be implemented as empty functions. Finally, the function
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* mtarch_init() is called by mt_init(), and can be used for
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* initalization of timer interrupts, or any other mechanisms required
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* for correct operation of the architecture specific support funcions.
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*
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*/
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/**
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* \file
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* Header file for the preemptive multitasking library for Contiki.
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* \author
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* Adam Dunkels <adam@sics.se>
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*
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*/
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#ifndef __MT_H__
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#define __MT_H__
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#include "contiki.h"
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/**
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* An opaque structure that is used for holding the state of a thread.
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*
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* The structure should be defined in the "mtarch.h" file. This
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* structure typically holds the entire stack for the thread.
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*/
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struct mtarch_thread;
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/**
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* Initialize the architecture specific support functions for the
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* multi-thread library.
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*
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* This function is implemented by the architecture specific functions
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* for the multi-thread library and is called by the mt_init()
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* function as part of the initialization of the library. The
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* mtarch_init() function can be used for, e.g., starting preemtion
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* timers or other architecture specific mechanisms required for the
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* operation of the library.
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*/
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void mtarch_init(void);
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/**
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* Uninstall library and clean up.
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*
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*/
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void mtarch_remove(void);
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/**
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* Setup the stack frame for a thread that is being started.
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*
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* This function is called by the mt_start() function in order to set
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* up the architecture specific stack of the thread to be started.
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*
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* \param thread A pointer to a struct mtarch_thread for the thread to
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* be started.
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*
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* \param function A pointer to the function that the thread will
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* start executing the first time it is scheduled to run.
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*
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* \param data A pointer to the argument that the function should be
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* passed.
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*/
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void mtarch_start(struct mtarch_thread *thread,
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void (* function)(void *data),
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void *data);
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/**
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* Yield the processor.
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*
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* This function is called by the mt_yield() function, which is called
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* from the running thread in order to give up the processor.
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*
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*/
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void mtarch_yield(void);
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/**
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* Start executing a thread.
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*
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* This function is called from mt_exec() and the purpose of the
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* function is to start execution of the thread. The function should
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* switch in the stack of the thread, and does not return until the
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* thread has explicitly yielded (using mt_yield()) or until it is
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* preempted.
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*
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*/
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void mtarch_exec(struct mtarch_thread *thread);
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void mtarch_pstart(void);
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void mtarch_pstop(void);
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/** @} */
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#include "mtarch.h"
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struct mt_thread {
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int state;
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process_event_t *evptr;
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process_data_t *dataptr;
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struct mtarch_thread thread;
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};
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/**
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* No error.
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*
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* \hideinitializer
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*/
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#define MT_OK 1
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/**
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* Initializes the multithreading library.
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*
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*/
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void mt_init(void);
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/**
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* Uninstalls library and cleans up.
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*
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*/
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void mt_remove(void);
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/**
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* Starts a multithreading thread.
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*
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* \param thread Pointer to an mt_thread struct that must have been
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* previously allocated by the caller.
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*
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* \param function A pointer to the entry function of the thread that is
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* to be set up.
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*
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* \param data A pointer that will be passed to the entry function.
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*
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*/
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void mt_start(struct mt_thread *thread, void (* function)(void *), void *data);
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/**
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* Execute parts of a thread.
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*
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* This function is called by a Contiki process and runs a
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* thread. The function does not return until the thread has yielded,
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* or is preempted.
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*
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* \note The thread must first be initialized with the mt_init() function.
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*
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* \param thread A pointer to a struct mt_thread block that must be
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* allocated by the caller.
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*
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*/
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void mt_exec(struct mt_thread *thread);
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/**
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* Post an event to a thread.
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*
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* This function posts an event to a thread. The thread will be
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* scheduled if the thread currently is waiting for the posted event
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* number. If the thread is not waiting for the event, this function
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* does nothing.
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*
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* \note The thread must first be initialized with the mt_init() function.
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*
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* \param thread A pointer to a struct mt_thread block that must be
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* allocated by the caller.
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*
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* \param s The event that is posted to the thread.
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*
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* \param data An opaque pointer to a user specified structure
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* containing additonal information, or NULL if no additional
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* information is needed.
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*/
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/*void mt_exec_event(struct mt_thread *thread, process_event_t s,
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process_data_t data);*/
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/**
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* Voluntarily give up the processor.
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*
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* This function is called by a running thread in order to give up
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* control of the CPU.
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*
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*/
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void mt_yield(void);
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/**
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* Post an event to another process.
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*
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* This function is called by a running thread and will emit a signal
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* to another Contiki process. This will cause the currently executing
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* thread to yield.
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*
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* \param p The process receiving the signal, or PROCESS_BROADCAST
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* for a broadcast event.
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*
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* \param ev The event to be posted.
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*
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* \param data A pointer to a message that is to be delivered together
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* with the signal.
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*
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*/
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/*void mt_post(struct process *p, process_event_t ev, process_data_t data);*/
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/**
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* Block and wait for an event to occur.
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*
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* This function can be called by a running thread in order to block
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* and wait for an event. The function returns when an event has
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* occured. The event number and the associated data are placed in the
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* variables pointed to by the function arguments.
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*
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* \param ev A pointer to a process_event_t variable. The variable
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* will be filled with the number event that woke the thread.
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*
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* \param data A pointer to a process_data_t variable. The variable
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* will be filled with the data associated with the event that woke
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* the thread.
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*
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*/
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/*void mt_wait(process_event_t *ev, process_data_t *data);*/
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/**
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* Exit a thread.
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*
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* This function is called from within an executing thread in order to
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* exit the thread. The function never returns.
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*
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*/
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void mt_exit(void);
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#if 0
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/**
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* \defgroup mtp Multi-threading library convenience functions
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* @{
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*
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* The Contiki multi-threading library has an interface that might be
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* hard to use. Therefore, the mtp module provides a simpler
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* interface.
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*
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* Example:
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\code
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static void
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example_thread_code(void *data)
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{
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while(1) {
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printf("Test\n");
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mt_yield();
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}
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}
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MTP(example_thread, "Example thread", p1, t1, t1_idle);
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int
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main(int argc, char *argv[])
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{
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mtp_start(&example_thread, example_thread_code, NULL);
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}
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\endcode
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*
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*/
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/**
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* Declare a multithreaded process.
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*
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* This macro is used to declare a multithreaded process.
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*
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* \hideinitializer
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*/
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#define MT_PROCESS(name, strname) \
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extern struct mt_process name##mt_process; \
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struct process name = { NULL, strname, mt_process_thread }; \
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static struct mt_process thread = {&name}
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struct mt_process {
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struct process *p;
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struct mt_thread t;
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};
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/**
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* Start a thread.
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*
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* This function starts the process in which the thread is to run, and
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* also sets up the thread to run within the process. The function
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* should be passed variable names declared with the MTP() macro.
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*
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* \param t A pointer to a thread structure previously declared with MTP().
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*
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* \param function A pointer to the function that the thread should
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* start executing.
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*
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* \param data A pointer that the function should be passed when first
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* invocated.
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*/
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void mtp_start(struct mt_process *p,
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void (* function)(void *), void *data);
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void mtp_exit(void);
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void mtp_eventhandler(process_event_t ev, process_data_t data);
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/** @} */
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#endif /* 0 */
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/** @} */
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/** @} */
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#endif /* __MT_H__ */
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