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
|
/*
ChibiOS - Copyright (C) 2006..2018 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 rt/include/chsem.h
* @brief Semaphores macros and structures.
*
* @addtogroup semaphores
* @{
*/
#ifndef CHSEM_H
#define CHSEM_H
#if (CH_CFG_USE_SEMAPHORES == TRUE) || defined(__DOXYGEN__)
/*===========================================================================*/
/* Module constants. */
/*===========================================================================*/
/*===========================================================================*/
/* Module pre-compile time settings. */
/*===========================================================================*/
/*===========================================================================*/
/* Derived constants and error checks. */
/*===========================================================================*/
/*===========================================================================*/
/* Module data structures and types. */
/*===========================================================================*/
/**
* @brief Semaphore structure.
*/
typedef struct ch_semaphore {
threads_queue_t queue; /**< @brief Queue of the threads sleeping
on this semaphore. */
cnt_t cnt; /**< @brief The semaphore counter. */
} semaphore_t;
/*===========================================================================*/
/* Module macros. */
/*===========================================================================*/
/**
* @brief Data part of a static semaphore initializer.
* @details This macro should be used when statically initializing a semaphore
* that is part of a bigger structure.
*
* @param[in] name the name of the semaphore variable
* @param[in] n the counter initial value, this value must be
* non-negative
*/
#define _SEMAPHORE_DATA(name, n) {_THREADS_QUEUE_DATA(name.queue), n}
/**
* @brief Static semaphore initializer.
* @details Statically initialized semaphores require no explicit
* initialization using @p chSemInit().
*
* @param[in] name the name of the semaphore variable
* @param[in] n the counter initial value, this value must be
* non-negative
*/
#define SEMAPHORE_DECL(name, n) semaphore_t name = _SEMAPHORE_DATA(name, n)
/*===========================================================================*/
/* External declarations. */
/*===========================================================================*/
#ifdef __cplusplus
extern "C" {
#endif
void chSemObjectInit(semaphore_t *sp, cnt_t n);
void chSemResetWithMessage(semaphore_t *sp, cnt_t n, msg_t msg);
void chSemResetWithMessageI(semaphore_t *sp, cnt_t n, msg_t msg);
msg_t chSemWait(semaphore_t *sp);
msg_t chSemWaitS(semaphore_t *sp);
msg_t chSemWaitTimeout(semaphore_t *sp, sysinterval_t timeout);
msg_t chSemWaitTimeoutS(semaphore_t *sp, sysinterval_t timeout);
void chSemSignal(semaphore_t *sp);
void chSemSignalI(semaphore_t *sp);
void chSemAddCounterI(semaphore_t *sp, cnt_t n);
msg_t chSemSignalWait(semaphore_t *sps, semaphore_t *spw);
#ifdef __cplusplus
}
#endif
/*===========================================================================*/
/* Module inline functions. */
/*===========================================================================*/
/**
* @brief Performs a reset operation on the semaphore.
* @post After invoking this function all the threads waiting on the
* semaphore, if any, are released and the semaphore counter is set
* to the specified, non negative, value.
* @note This function implicitly sends @p MSG_RESET as message.
*
* @param[in] sp pointer to a @p semaphore_t structure
* @param[in] n the new value of the semaphore counter. The value must
* be non-negative.
*
* @api
*/
static inline void chSemReset(semaphore_t *sp, cnt_t n) {
chSemResetWithMessage(sp, n, MSG_RESET);
}
/**
* @brief Performs a reset operation on the semaphore.
* @post After invoking this function all the threads waiting on the
* semaphore, if any, are released and the semaphore counter is set
* to the specified, non negative, value.
* @post This function does not reschedule so a call to a rescheduling
* function must be performed before unlocking the kernel. Note that
* interrupt handlers always reschedule on exit so an explicit
* reschedule must not be performed in ISRs.
* @note This function implicitly sends @p MSG_RESET as message.
*
* @param[in] sp pointer to a @p semaphore_t structure
* @param[in] n the new value of the semaphore counter. The value must
* be non-negative.
*
* @iclass
*/
static inline void chSemResetI(semaphore_t *sp, cnt_t n) {
chSemResetWithMessageI(sp, n, MSG_RESET);
}
/**
* @brief Decreases the semaphore counter.
* @details This macro can be used when the counter is known to be positive.
*
* @param[in] sp pointer to a @p semaphore_t structure
*
* @iclass
*/
static inline void chSemFastWaitI(semaphore_t *sp) {
chDbgCheckClassI();
sp->cnt--;
}
/**
* @brief Increases the semaphore counter.
* @details This macro can be used when the counter is known to be not
* negative.
*
* @param[in] sp pointer to a @p semaphore_t structure
*
* @iclass
*/
static inline void chSemFastSignalI(semaphore_t *sp) {
chDbgCheckClassI();
sp->cnt++;
}
/**
* @brief Returns the semaphore counter current value.
*
* @param[in] sp pointer to a @p semaphore_t structure
* @return The semaphore counter value.
*
* @iclass
*/
static inline cnt_t chSemGetCounterI(const semaphore_t *sp) {
chDbgCheckClassI();
return sp->cnt;
}
#endif /* CH_CFG_USE_SEMAPHORES == TRUE */
#endif /* CHSEM_H */
/** @} */
|
