Contiki-NG
rtimer.h
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1 /*
2  * Copyright (c) 2005, Swedish Institute of Computer Science
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  * notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  * notice, this list of conditions and the following disclaimer in the
12  * documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the Institute nor the names of its contributors
14  * may be used to endorse or promote products derived from this software
15  * without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * This file is part of the Contiki operating system.
30  *
31  */
32 
33 /**
34  * \file
35  * Header file for the real-time timer module.
36  * \author
37  * Adam Dunkels <adam@sics.se>
38  *
39  */
40 
41 /** \addtogroup threads
42  * @{ */
43 
44 /**
45  * \defgroup rt Real-time task scheduling
46  *
47  * The real-time module handles the scheduling and execution of
48  * real-time tasks (with predictable execution times).
49  *
50  * @{
51  */
52 
53 #ifndef RTIMER_H_
54 #define RTIMER_H_
55 
56 #include "contiki.h"
57 
58 /** \brief The rtimer size (in bytes) */
59 #ifdef RTIMER_CONF_CLOCK_SIZE
60 #define RTIMER_CLOCK_SIZE RTIMER_CONF_CLOCK_SIZE
61 #else /* RTIMER_CONF_CLOCK_SIZE */
62 /* Default: 32bit rtimer*/
63 #define RTIMER_CLOCK_SIZE 4
64 #endif /* RTIMER_CONF_CLOCK_SIZE */
65 
66 #if RTIMER_CLOCK_SIZE == 2
67 /* 16-bit rtimer */
68 typedef uint16_t rtimer_clock_t;
69 #define RTIMER_CLOCK_DIFF(a,b) ((int16_t)((a)-(b)))
70 
71 #elif RTIMER_CLOCK_SIZE == 4
72 /* 32-bit rtimer */
73 typedef uint32_t rtimer_clock_t;
74 #define RTIMER_CLOCK_DIFF(a, b) ((int32_t)((a) - (b)))
75 
76 #elif RTIMER_CLOCK_SIZE == 8
77 /* 64-bit rtimer */
78 typedef uint64_t rtimer_clock_t;
79 #define RTIMER_CLOCK_DIFF(a,b) ((int64_t)((a)-(b)))
80 
81 #else
82 #error Unsupported rtimer size (check RTIMER_CLOCK_SIZE)
83 #endif
84 
85 #define RTIMER_CLOCK_MAX ((rtimer_clock_t)-1)
86 #define RTIMER_CLOCK_LT(a, b) (RTIMER_CLOCK_DIFF((a),(b)) < 0)
87 
88 #include "rtimer-arch.h"
89 
90 /**
91  * \brief Initialize the real-time scheduler.
92  *
93  * This function initializes the real-time scheduler and
94  * must be called at boot-up, before any other functions
95  * from the real-time scheduler is called.
96  */
97 void rtimer_init(void);
98 
99 struct rtimer;
100 typedef void (* rtimer_callback_t)(struct rtimer *t, void *ptr);
101 
102 /**
103  * \brief Representation of a real-time task
104  *
105  * This structure represents a real-time task and is used
106  * by the real-time module and the architecture specific
107  * support module for the real-time module.
108  */
109 struct rtimer {
110  rtimer_clock_t time;
111  rtimer_callback_t func;
112  void *ptr;
113 };
114 
115 enum {
116  RTIMER_OK,
117  RTIMER_ERR_FULL,
118  RTIMER_ERR_TIME,
119  RTIMER_ERR_ALREADY_SCHEDULED,
120 };
121 
122 /**
123  * \brief Post a real-time task.
124  * \param task A pointer to the task variable previously declared with RTIMER_TASK().
125  * \param time The time when the task is to be executed.
126  * \param duration Unused argument.
127  * \param func A function to be called when the task is executed.
128  * \param ptr An opaque pointer that will be supplied as an argument to the callback function.
129  * \return Non-zero (true) if the task could be scheduled, zero
130  * (false) if the task could not be scheduled.
131  *
132  * This function schedules a real-time task at a specified
133  * time in the future.
134  *
135  */
136 int rtimer_set(struct rtimer *task, rtimer_clock_t time,
137  rtimer_clock_t duration, rtimer_callback_t func, void *ptr);
138 
139 /**
140  * \brief Execute the next real-time task and schedule the next task, if any
141  *
142  * This function is called by the architecture dependent
143  * code to execute and schedule the next real-time task.
144  *
145  */
146 void rtimer_run_next(void);
147 
148 /**
149  * \brief Get the current clock time
150  * \return The current time
151  *
152  * This function returns what the real-time module thinks
153  * is the current time. The current time is used to set
154  * the timeouts for real-time tasks.
155  *
156  * \hideinitializer
157  */
158 #define RTIMER_NOW() rtimer_arch_now()
159 
160 /**
161  * \brief Get the time that a task last was executed
162  * \param task The task
163  * \return The time that a task last was executed
164  *
165  * This function returns the time that the task was last
166  * executed. This typically is used to get a periodic
167  * execution of a task without clock drift.
168  *
169  * \hideinitializer
170  */
171 #define RTIMER_TIME(task) ((task)->time)
172 
173 void rtimer_arch_init(void);
174 void rtimer_arch_schedule(rtimer_clock_t t);
175 /*rtimer_clock_t rtimer_arch_now(void);*/
176 
177 #define RTIMER_SECOND RTIMER_ARCH_SECOND
178 
179 /* RTIMER_GUARD_TIME is the minimum amount of rtimer ticks between
180  the current time and the future time when a rtimer is scheduled.
181  Necessary to avoid accidentally scheduling a rtimer in the past
182  on platforms with fast rtimer ticks. Should be >= 2. */
183 #ifdef RTIMER_CONF_GUARD_TIME
184 #define RTIMER_GUARD_TIME RTIMER_CONF_GUARD_TIME
185 #else /* RTIMER_CONF_GUARD_TIME */
186 #define RTIMER_GUARD_TIME (RTIMER_ARCH_SECOND >> 14)
187 #endif /* RTIMER_CONF_GUARD_TIME */
188 
189 #endif /* RTIMER_H_ */
190 
191 /** @} */
192 /** @} */
int rtimer_set(struct rtimer *rtimer, rtimer_clock_t time, rtimer_clock_t duration, rtimer_callback_t func, void *ptr)
Post a real-time task.
Definition: rtimer.c:67
Representation of a real-time task.
Definition: rtimer.h:109
void rtimer_run_next(void)
Execute the next real-time task and schedule the next task, if any.
Definition: rtimer.c:92
void rtimer_arch_init(void)
We don&#39;t need to explicitly initialise anything but this routine is required by the API...
Definition: rtimer-arch.c:59
void rtimer_init(void)
Initialize the real-time scheduler.
Definition: rtimer.c:61
void rtimer_arch_schedule(rtimer_clock_t t)
Schedules an rtimer task to be triggered at time t.
Definition: rtimer-arch.c:71