diff --git a/core/sys/rt.c b/core/sys/rt.c new file mode 100644 index 000000000..669239d16 --- /dev/null +++ b/core/sys/rt.c @@ -0,0 +1,153 @@ +/* + * 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.c,v 1.1 2007/03/19 00:16:13 adamdunkels Exp $ + */ + +#include "sys/rt.h" +#include "contiki.h" + +#define LIST_SIZE 16 + +static struct rt_task *tasks[LIST_SIZE]; +static u8_t next, firstempty; + +#define DEBUG 0 +#if DEBUG +#include +#define PRINTF(...) printf(__VA_ARGS__) +#else +#define PRINTF(...) +#endif + +/*---------------------------------------------------------------------------*/ +void +rt_init(void) +{ + next = 0; + firstempty = 0; + rt_arch_init(); +} +/*---------------------------------------------------------------------------*/ +int +rt_post(struct rt_task *task, rt_clock_t time, rt_clock_t duration) +{ + int i; + + PRINTF("rt_post time %d\n", time); + + /* Check if task queue is full. */ + if(firstempty == (next - 1) % LIST_SIZE) { + PRINTF("rt_post: next %d firstempty %d full\n", next, firstempty); + return RT_ERR_FULL; + } + + /* Check if it is possible to run this task at the requested + time. */ + for(i = next; i != firstempty; + i = (i + 1) % LIST_SIZE) { + + /* XXX: should check a range of time not just the same precise + moment. */ + if(tasks[i]->time == time) { + PRINTF("rt_post: next %d firstempty %d time %d == %d\n", + next, firstempty, tasks[i]->time, time); + return RT_ERR_TIME; + } + } + /* Put the task at the end of the task list. */ + task->time = time; + tasks[firstempty] = task; + PRINTF("rt_post: putting task %s as %d\n", task->name, firstempty); + + firstempty = (firstempty + 1) % LIST_SIZE; + + /* PRINTF("rt_post: next %d firstempty %d scheduling soon\n", + next, firstempty);*/ + + /* Check if this is the first task on the list. If so, we need to + run the rt_arch_schedule() function to get the ball rolling. */ + if(firstempty == (next + 1) % LIST_SIZE) { + + PRINTF("rt_post scheduling %d %s (%d)\n", + next, tasks[next]->name, tasks[next]->time); + rt_arch_schedule(time); + } + + return RT_OK; +} +/*---------------------------------------------------------------------------*/ +void +rt_task_run(void) +{ + int i, n; + struct rt_task *t; + + t = tasks[next]; + + /* Increase the pointer to the next task. */ + next = (next + 1) % LIST_SIZE; + + /* Run the task. */ + PRINTF("rt_task_run running %s\n", t->name); + t->func(t, t->ptr); + + if(next == firstempty) { + PRINTF("rt_task_run: empty task list\n"); + /* The list is empty, no more tasks to schedule. */ + return; + } + + /* Find the next task to run. */ + n = next; + for(i = next; i != firstempty; i = (i + 1) % LIST_SIZE) { + PRINTF("rt_task_run checking %s (%d) against %s (%d)\n", + tasks[i]->name, tasks[i]->time, + tasks[n]->name, tasks[n]->time); + if(tasks[i]->prio >= tasks[n]->prio && + RT_CLOCK_LT(tasks[i]->time, tasks[n]->time)) { + n = i; + } + } + + PRINTF("rt_task_run next task is %d %s (%d)\n", + n, tasks[n]->name, tasks[n]->time); + + /* Put the next task first in the task list. */ + t = tasks[next]; + tasks[next] = tasks[n]; + tasks[n] = t; + + PRINTF("rt_task_run scheduling %d %s (%d)\n", + next, tasks[next]->name, tasks[next]->time); + + rt_arch_schedule(tasks[next]->time); +} +/*---------------------------------------------------------------------------*/ diff --git a/core/sys/rt.h b/core/sys/rt.h new file mode 100644 index 000000000..eedf3f9a9 --- /dev/null +++ b/core/sys/rt.h @@ -0,0 +1,156 @@ +/** + * \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 + * + */ + +/* + * 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__ */ + +/** @} */