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
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
|
/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT 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/RT 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 chevents.c
* @brief Events code.
*
* @addtogroup events
* @details Event Flags, Event Sources and Event Listeners.
* <h2>Operation mode</h2>
* Each thread has a mask of pending event flags inside its @p Thread
* structure.
* Several operations are defined:
* - <b>Wait</b>, the invoking thread goes to sleep until a certain
* AND/OR combination of event flags becomes pending.
* - <b>Clear</b>, a mask of event flags is cleared from the pending
* events mask, the cleared event flags mask is returned (only the
* flags that were actually pending and then cleared).
* - <b>Signal</b>, an event mask is directly ORed to the mask of the
* signaled thread.
* - <b>Broadcast</b>, each thread registered on an Event Source is
* signaled with the event flags specified in its Event Listener.
* - <b>Dispatch</b>, an events mask is scanned and for each bit set
* to one an associated handler function is invoked. Bit masks are
* scanned from bit zero upward.
* .
* An Event Source is a special object that can be "broadcasted" by
* a thread or an interrupt service routine. Broadcasting an Event
* Source has the effect that all the threads registered on the
* Event Source will be signaled with an events mask.<br>
* An unlimited number of Event Sources can exists in a system and
* each thread can be listening on an unlimited number of
* them.<br><br>
* In order to use the Events APIs the @p CH_USE_EVENTS option must be
* enabled in @p chconf.h.
* @{
*/
#include "ch.h"
#if CH_USE_EVENTS
/**
* @brief Registers an Event Listener on an Event Source.
* @note Multiple Event Listeners can specify the same bits to be pended.
*
* @param[in] esp pointer to the @p EventSource structure
* @param[in] elp pointer to the @p EventListener structure
* @param[in] mask the mask of event flags to be pended to the thread when
* the event source is broadcasted
*/
void chEvtRegisterMask(EventSource *esp, EventListener *elp, eventmask_t mask) {
chDbgCheck((esp != NULL) && (elp != NULL), "chEvtRegisterMask");
chSysLock();
elp->el_next = esp->es_next;
esp->es_next = elp;
elp->el_listener = currp;
elp->el_mask = mask;
chSysUnlock();
}
/**
* @brief Unregisters an Event Listener from its Event Source.
* @note If the event listener is not registered on the specified event
* source then the function does nothing.
* @note For optimal performance it is better to perform the unregister
* operations in inverse order of the register operations (elements
* are found on top of the list).
*
* @param[in] esp pointer to the @p EventSource structure
* @param[in] elp pointer to the @p EventListener structure
*/
void chEvtUnregister(EventSource *esp, EventListener *elp) {
EventListener *p;
chDbgCheck((esp != NULL) && (elp != NULL), "chEvtUnregister");
p = (EventListener *)esp;
chSysLock();
while (p->el_next != (EventListener *)esp) {
if (p->el_next == elp) {
p->el_next = elp->el_next;
break;
}
p = p->el_next;
}
chSysUnlock();
}
/**
* @brief Clears the pending events specified in the mask.
*
* @param[in] mask the events to be cleared
* @return The pending events that were cleared.
*/
eventmask_t chEvtClear(eventmask_t mask) {
eventmask_t m;
chSysLock();
m = currp->p_epending & mask;
currp->p_epending &= ~mask;
chSysUnlock();
return m;
}
/**
* @brief Pends a set of event flags on the current thread, this is @b much
* faster than using @p chEvtBroadcast() or @p chEvtSignal().
*
* @param[in] mask the events to be pended
* @return The current pending events mask.
*/
eventmask_t chEvtPend(eventmask_t mask) {
chSysLock();
mask = (currp->p_epending |= mask);
chSysUnlock();
return mask;
}
/**
* @brief Pends a set of event flags on the specified @p Thread.
*
* @param[in] tp the thread to be signaled
* @param[in] mask the event flags set to be pended
*/
void chEvtSignal(Thread *tp, eventmask_t mask) {
chDbgCheck(tp != NULL, "chEvtSignal");
chSysLock();
chEvtSignalI(tp, mask);
chSchRescheduleS();
chSysUnlock();
}
/**
* @brief Pends a set of event flags on the specified @p Thread.
*
* @param[in] tp the thread to be signaled
* @param[in] mask the event flags set to be pended
*/
void chEvtSignalI(Thread *tp, eventmask_t mask) {
chDbgCheck(tp != NULL, "chEvtSignalI");
tp->p_epending |= mask;
/* Test on the AND/OR conditions wait states.*/
if (((tp->p_state == THD_STATE_WTOREVT) &&
((tp->p_epending & tp->p_u.ewmask) != 0)) ||
((tp->p_state == THD_STATE_WTANDEVT) &&
((tp->p_epending & tp->p_u.ewmask) == tp->p_u.ewmask)))
chSchReadyI(tp)->p_u.rdymsg = RDY_OK;
}
/**
* @brief Signals all the Event Listeners registered on the specified Event
* Source.
*
* @param[in] esp pointer to the @p EventSource structure
*/
void chEvtBroadcast(EventSource *esp) {
chSysLock();
chEvtBroadcastI(esp);
chSchRescheduleS();
chSysUnlock();
}
/**
* @brief Signals all the Event Listeners registered on the specified Event
* Source.
*
* @param[in] esp pointer to the @p EventSource structure
*/
void chEvtBroadcastI(EventSource *esp) {
EventListener *elp;
chDbgCheck(esp != NULL, "chEvtBroadcastI");
elp = esp->es_next;
while (elp != (EventListener *)esp) {
chEvtSignalI(elp->el_listener, elp->el_mask);
elp = elp->el_next;
}
}
/**
* @brief Invokes the event handlers associated to an event flags mask.
*
* @param[in] mask mask of the events to be dispatched
* @param[in] handlers an array of @p evhandler_t. The array must have size
* equal to the number of bits in eventmask_t.
*/
void chEvtDispatch(const evhandler_t *handlers, eventmask_t mask) {
eventid_t eid;
chDbgCheck(handlers != NULL, "chEvtDispatch");
eid = 0;
while (mask) {
if (mask & EVENT_MASK(eid)) {
chDbgAssert(handlers[eid] != NULL,
"chEvtDispatch(), #1",
"null handler");
mask &= ~EVENT_MASK(eid);
handlers[eid](eid);
}
eid++;
}
}
#if CH_OPTIMIZE_SPEED || !CH_USE_EVENTS_TIMEOUT || defined(__DOXYGEN__)
/**
* @brief Waits for exactly one of the specified events.
* @details The function waits for one event among those specified in
* @p mask to become pending then the event is cleared and returned.
* @note One and only one event is served in the function, the one with the
* lowest event id. The function is meant to be invoked into a loop in
* order to serve all the pending events.<br>
* This means that Event Listeners with a lower event identifier have
* an higher priority.
*
* @param[in] mask mask of the events that the function should wait for,
* @p ALL_EVENTS enables all the events
* @return The mask of the lowest id served and cleared event.
*/
eventmask_t chEvtWaitOne(eventmask_t mask) {
Thread *ctp = currp;
eventmask_t m;
chSysLock();
if ((m = (ctp->p_epending & mask)) == 0) {
ctp->p_u.ewmask = mask;
chSchGoSleepS(THD_STATE_WTOREVT);
m = ctp->p_epending & mask;
}
m &= -m;
ctp->p_epending &= ~m;
chSysUnlock();
return m;
}
/**
* @brief Waits for any of the specified events.
* @details The function waits for any event among those specified in
* @p mask to become pending then the events are cleared and returned.
*
* @param[in] mask mask of the events that the function should wait for,
* @p ALL_EVENTS enables all the events
* @return The mask of the served and cleared events.
*/
eventmask_t chEvtWaitAny(eventmask_t mask) {
Thread *ctp = currp;
eventmask_t m;
chSysLock();
if ((m = (ctp->p_epending & mask)) == 0) {
ctp->p_u.ewmask = mask;
chSchGoSleepS(THD_STATE_WTOREVT);
m = ctp->p_epending & mask;
}
ctp->p_epending &= ~m;
chSysUnlock();
return m;
}
/**
* @brief Waits for all the specified events.
* @details The function waits for all the events specified in @p mask to
* become pending then the events are cleared and returned.
*
* @param[in] mask mask of the event ids that the function should wait for
* @return The mask of the served and cleared events.
*/
eventmask_t chEvtWaitAll(eventmask_t mask) {
Thread *ctp = currp;
chSysLock();
if ((ctp->p_epending & mask) != mask) {
ctp->p_u.ewmask = mask;
chSchGoSleepS(THD_STATE_WTANDEVT);
}
ctp->p_epending &= ~mask;
chSysUnlock();
return mask;
}
#endif /* CH_OPTIMIZE_SPEED || !CH_USE_EVENTS_TIMEOUT */
#if CH_USE_EVENTS_TIMEOUT
/**
* @brief Waits for exactly one of the specified events.
* @details The function waits for one event among those specified in
* @p mask to become pending then the event is cleared and returned.
* @note One and only one event is served in the function, the one with the
* lowest event id. The function is meant to be invoked into a loop in
* order to serve all the pending events.<br>
* This means that Event Listeners with a lower event identifier have
* an higher priority.
*
* @param[in] mask mask of the events that the function should wait for,
* @p ALL_EVENTS enables all the events
* @param[in] time the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_IMMEDIATE immediate timeout.
* - @a TIME_INFINITE no timeout.
* .
* @return The mask of the lowest id served and cleared event.
* @retval 0 if the specified timeout expired.
*/
eventmask_t chEvtWaitOneTimeout(eventmask_t mask, systime_t time) {
Thread *ctp = currp;
eventmask_t m;
chSysLock();
if ((m = (ctp->p_epending & mask)) == 0) {
if (TIME_IMMEDIATE == time)
return (eventmask_t)0;
ctp->p_u.ewmask = mask;
if (chSchGoSleepTimeoutS(THD_STATE_WTOREVT, time) < RDY_OK)
return (eventmask_t)0;
m = ctp->p_epending & mask;
}
m &= -m;
ctp->p_epending &= ~m;
chSysUnlock();
return m;
}
/**
* @brief Waits for any of the specified events.
* @details The function waits for any event among those specified in
* @p mask to become pending then the events are cleared and
* returned.
*
* @param[in] mask mask of the events that the function should wait for,
* @p ALL_EVENTS enables all the events
* @param[in] time the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_IMMEDIATE immediate timeout.
* - @a TIME_INFINITE no timeout.
* .
* @return The mask of the served and cleared events.
* @retval 0 if the specified timeout expired.
*/
eventmask_t chEvtWaitAnyTimeout(eventmask_t mask, systime_t time) {
Thread *ctp = currp;
eventmask_t m;
chSysLock();
if ((m = (ctp->p_epending & mask)) == 0) {
if (TIME_IMMEDIATE == time)
return (eventmask_t)0;
ctp->p_u.ewmask = mask;
if (chSchGoSleepTimeoutS(THD_STATE_WTOREVT, time) < RDY_OK)
return (eventmask_t)0;
m = ctp->p_epending & mask;
}
ctp->p_epending &= ~m;
chSysUnlock();
return m;
}
/**
* @brief Waits for all the specified events.
* @details The function waits for all the events specified in @p mask to
* become pending then the events are cleared and returned.
*
* @param[in] mask mask of the event ids that the function should wait for
* @param[in] time the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_IMMEDIATE immediate timeout.
* - @a TIME_INFINITE no timeout.
* .
* @return The mask of the served and cleared events.
* @retval 0 if the specified timeout expired.
*/
eventmask_t chEvtWaitAllTimeout(eventmask_t mask, systime_t time) {
Thread *ctp = currp;
chSysLock();
if ((ctp->p_epending & mask) != mask) {
if (TIME_IMMEDIATE == time)
return (eventmask_t)0;
ctp->p_u.ewmask = mask;
if (chSchGoSleepTimeoutS(THD_STATE_WTANDEVT, time) < RDY_OK)
return (eventmask_t)0;
}
ctp->p_epending &= ~mask;
chSysUnlock();
return mask;
}
#endif /* CH_USE_EVENTS_TIMEOUT */
#endif /* CH_USE_EVENTS */
/** @} */
|