1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
|
/*
ChibiOS - Copyright (C) 2006..2015 Giovanni Di Sirio.
This file is part of ChibiOS.
ChibiOS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file chvt.c
* @brief Time and Virtual Timers module code.
*
* @addtogroup time
* @details Time and Virtual Timers related APIs and services.
* @{
*/
#include "ch.h"
/*===========================================================================*/
/* Module local definitions. */
/*===========================================================================*/
/*===========================================================================*/
/* Module exported variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local types. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local functions. */
/*===========================================================================*/
/*===========================================================================*/
/* Module exported functions. */
/*===========================================================================*/
/**
* @brief Virtual Timers initialization.
* @note Internal use only.
*
* @notapi
*/
void _vt_init(void) {
ch.vtlist.vt_next = (virtual_timer_t *)&ch.vtlist;
ch.vtlist.vt_prev = (virtual_timer_t *)&ch.vtlist;
ch.vtlist.vt_delta = (systime_t)-1;
#if CH_CFG_ST_TIMEDELTA == 0
ch.vtlist.vt_systime = 0;
#else /* CH_CFG_ST_TIMEDELTA > 0 */
ch.vtlist.vt_lasttime = 0;
#endif /* CH_CFG_ST_TIMEDELTA > 0 */
}
/**
* @brief Enables a virtual timer.
* @details The timer is enabled and programmed to trigger after the delay
* specified as parameter.
* @pre The timer must not be already armed before calling this function.
* @note The callback function is invoked from interrupt context.
*
* @param[out] vtp the @p virtual_timer_t structure pointer
* @param[in] delay the number of ticks before the operation timeouts, the
* special values are handled as follow:
* - @a TIME_INFINITE is allowed but interpreted as a
* normal time specification.
* - @a TIME_IMMEDIATE this value is not allowed.
* .
* @param[in] vtfunc the timer callback function. After invoking the
* callback the timer is disabled and the structure can
* be disposed or reused.
* @param[in] par a parameter that will be passed to the callback
* function
*
* @iclass
*/
void chVTDoSetI(virtual_timer_t *vtp, systime_t delay,
vtfunc_t vtfunc, void *par) {
virtual_timer_t *p;
chDbgCheckClassI();
chDbgCheck((vtp != NULL) && (vtfunc != NULL) && (delay != TIME_IMMEDIATE));
vtp->vt_par = par;
vtp->vt_func = vtfunc;
p = ch.vtlist.vt_next;
#if (CH_CFG_ST_TIMEDELTA > 0) || defined(__DOXYGEN__)
{
systime_t now = port_timer_get_time();
/* If the requested delay is lower than the minimum safe delta then it
is raised to the minimum safe value.*/
if (delay < (systime_t)CH_CFG_ST_TIMEDELTA) {
delay = (systime_t)CH_CFG_ST_TIMEDELTA;
}
if (&ch.vtlist == (virtual_timers_list_t *)p) {
/* The delta list is empty, the current time becomes the new
delta list base time.*/
ch.vtlist.vt_lasttime = now;
port_timer_start_alarm(ch.vtlist.vt_lasttime + delay);
}
else {
/* Now the delay is calculated as delta from the last tick interrupt
time.*/
delay += now - ch.vtlist.vt_lasttime;
/* If the specified delay is closer in time than the first element
in the delta list then it becomes the next alarm event in time.*/
if (delay < p->vt_delta) {
port_timer_set_alarm(ch.vtlist.vt_lasttime + delay);
}
}
}
#endif /* CH_CFG_ST_TIMEDELTA > 0 */
/* The delta list is scanned in order to find the correct position for
this timer. */
while (p->vt_delta < delay) {
delay -= p->vt_delta;
p = p->vt_next;
}
/* The timer is inserted in the delta list.*/
vtp->vt_next = p;
vtp->vt_prev = vtp->vt_next->vt_prev;
vtp->vt_prev->vt_next = vtp;
p->vt_prev = vtp;
vtp->vt_delta = delay
/* Special case when the timer is in last position in the list, the
value in the header must be restored.*/;
p->vt_delta -= delay;
ch.vtlist.vt_delta = (systime_t)-1;
}
/**
* @brief Disables a Virtual Timer.
* @pre The timer must be in armed state before calling this function.
*
* @param[in] vtp the @p virtual_timer_t structure pointer
*
* @iclass
*/
void chVTDoResetI(virtual_timer_t *vtp) {
chDbgCheckClassI();
chDbgCheck(vtp != NULL);
chDbgAssert(vtp->vt_func != NULL, "timer not set or already triggered");
/* Removing the element from the delta list.*/
vtp->vt_next->vt_delta += vtp->vt_delta;
vtp->vt_prev->vt_next = vtp->vt_next;
vtp->vt_next->vt_prev = vtp->vt_prev;
vtp->vt_func = NULL;
/* The above code changes the value in the header when the removed element
is the last of the list, restoring it.*/
ch.vtlist.vt_delta = (systime_t)-1;
#if (CH_CFG_ST_TIMEDELTA > 0) || defined(__DOXYGEN__)
{
if (&ch.vtlist == (virtual_timers_list_t *)ch.vtlist.vt_next) {
/* Just removed the last element in the list, alarm timer stopped.*/
port_timer_stop_alarm();
}
else {
/* Updating the alarm to the next deadline, deadline that must not be
closer in time than the minimum time delta.*/
if (ch.vtlist.vt_next->vt_delta >= (systime_t)CH_CFG_ST_TIMEDELTA) {
port_timer_set_alarm(ch.vtlist.vt_lasttime +
ch.vtlist.vt_next->vt_delta);
}
else {
port_timer_set_alarm(ch.vtlist.vt_lasttime +
(systime_t)CH_CFG_ST_TIMEDELTA);
}
}
}
#endif /* CH_CFG_ST_TIMEDELTA > 0 */
}
/** @} */
|
