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/*
ChibiOS/GFX - Copyright (C) 2012
Joel Bodenmann aka Tectu <joel@unormal.org>
This file is part of ChibiOS/GFX.
ChibiOS/GFX 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/GFX 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 src/gtimer/gtimer.c
* @brief GTIMER sub-system code.
*
* @addtogroup GTIMER
* @{
*/
#include "ch.h"
#include "hal.h"
#include "gfx.h"
#if GFX_USE_GTIMER || defined(__DOXYGEN__)
#if !CH_USE_MUTEXES || !CH_USE_SEMAPHORES
#error "GTIMER: CH_USE_MUTEXES and CH_USE_SEMAPHORES must be defined in chconf.h"
#endif
#define GTIMER_FLG_PERIODIC 0x0001
#define GTIMER_FLG_INFINITE 0x0002
#define GTIMER_FLG_JABBED 0x0004
#define GTIMER_FLG_SCHEDULED 0x0008
/* Don't rework this macro to use a ternary operator - the gcc compiler stuffs it up */
#define TimeIsWithin(x, start, end) ((end >= start && x >= start && x <= end) || (end < start && (x >= start || x <= end)))
/* This mutex protects access to our tables */
static MUTEX_DECL(mutex);
static Thread *pThread = 0;
static GTimer *pTimerHead = 0;
static BSEMAPHORE_DECL(waitsem, TRUE);
static WORKING_AREA(waTimerThread, GTIMER_THREAD_WORKAREA_SIZE);
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
static msg_t GTimerThreadHandler(void *arg) {
(void)arg;
GTimer *pt;
systime_t tm;
systime_t nxtTimeout;
systime_t lastTime;
GTimerFunction fn;
void *param;
#if CH_USE_REGISTRY
chRegSetThreadName("GTimer");
#endif
nxtTimeout = TIME_INFINITE;
lastTime = 0;
while(1) {
/* Wait for work to do. */
chThdYield(); // Give someone else a go no matter how busy we are
chBSemWaitTimeout(&waitsem, nxtTimeout);
restartTimerChecks:
// Our reference time
tm = chTimeNow();
nxtTimeout = TIME_INFINITE;
/* We need to obtain the mutex */
chMtxLock(&mutex);
if (pTimerHead) {
pt = pTimerHead;
do {
// Do we have something to do for this timer?
if ((pt->flags & GTIMER_FLG_JABBED) || (!(pt->flags & GTIMER_FLG_INFINITE) && TimeIsWithin(pt->when, lastTime, tm))) {
// Is this timer periodic?
if ((pt->flags & GTIMER_FLG_PERIODIC) && pt->period != TIME_IMMEDIATE) {
// Yes - Update ready for the next period
if (!(pt->flags & GTIMER_FLG_INFINITE)) {
// We may have skipped a period.
// We use this complicated formulae rather than a loop
// because the gcc compiler stuffs up the loop so that it
// either loops forever or doesn't get executed at all.
pt->when += ((tm + pt->period - pt->when) / pt->period) * pt->period;
}
// We are definitely no longer jabbed
pt->flags &= ~GTIMER_FLG_JABBED;
} else {
// No - get us off the timers list
if (pt->next == pt->prev)
pTimerHead = 0;
else {
pt->next->prev = pt->prev;
pt->prev->next = pt->next;
if (pTimerHead == pt)
pTimerHead = pt->next;
}
pt->flags = 0;
}
// Call the callback function
fn = pt->fn;
param = pt->param;
chMtxUnlock();
fn(param);
// We no longer hold the mutex, the callback function may have taken a while
// and our list may have been altered so start again!
goto restartTimerChecks;
}
// Find when we next need to wake up
if (!(pt->flags & GTIMER_FLG_INFINITE) && pt->when - tm < nxtTimeout)
nxtTimeout = pt->when - tm;
pt = pt->next;
} while(pt != pTimerHead);
}
// Ready for the next loop
lastTime = tm;
chMtxUnlock();
}
return 0;
}
void gtimerInit(GTimer *pt) {
pt->flags = 0;
}
void gtimerStart(GTimer *pt, GTimerFunction fn, void *param, bool_t periodic, systime_t millisec) {
chMtxLock(&mutex);
// Start our thread if not already going
if (!pThread)
pThread = chThdCreateStatic(waTimerThread, sizeof(waTimerThread), HIGHPRIO, GTimerThreadHandler, NULL);
// Is this already scheduled?
if (pt->flags & GTIMER_FLG_SCHEDULED) {
// Cancel it!
if (pt->next == pt->prev)
pTimerHead = 0;
else {
pt->next->prev = pt->prev;
pt->prev->next = pt->next;
if (pTimerHead == pt)
pTimerHead = pt->next;
}
}
// Set up the timer structure
pt->fn = fn;
pt->param = param;
pt->flags = GTIMER_FLG_SCHEDULED;
if (periodic)
pt->flags |= GTIMER_FLG_PERIODIC;
if (millisec == TIME_INFINITE) {
pt->flags |= GTIMER_FLG_INFINITE;
pt->period = TIME_INFINITE;
} else {
pt->period = MS2ST(millisec);
pt->when = chTimeNow() + pt->period;
}
// Just pop it on the end of the queue
if (pTimerHead) {
pt->next = pTimerHead;
pt->prev = pTimerHead->prev;
pt->prev->next = pt;
pt->next->prev = pt;
} else
pt->next = pt->prev = pTimerHead = pt;
// Bump the thread
if (!(pt->flags & GTIMER_FLG_INFINITE))
chBSemSignal(&waitsem);
chMtxUnlock();
}
void gtimerStop(GTimer *pt) {
chMtxLock(&mutex);
if (pt->flags & GTIMER_FLG_SCHEDULED) {
// Cancel it!
if (pt->next == pt->prev)
pTimerHead = 0;
else {
pt->next->prev = pt->prev;
pt->prev->next = pt->next;
if (pTimerHead == pt)
pTimerHead = pt->next;
}
// Make sure we know the structure is dead!
pt->flags = 0;
}
chMtxUnlock();
}
bool_t gtimerIsActive(GTimer *pt) {
return (pt->flags & GTIMER_FLG_SCHEDULED) ? TRUE : FALSE;
}
void gtimerJab(GTimer *pt) {
chMtxLock(&mutex);
// Jab it!
pt->flags |= GTIMER_FLG_JABBED;
// Bump the thread
chBSemSignal(&waitsem);
chMtxUnlock();
}
void gtimerJabI(GTimer *pt) {
// Jab it!
pt->flags |= GTIMER_FLG_JABBED;
// Bump the thread
chBSemSignalI(&waitsem);
}
#endif /* GFX_USE_GTIMER */
/** @} */
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