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/*
ChibiOS/RT - Copyright (C) 2006-2007 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 chsys.c
* @brief System related code.
* @addtogroup system
* @{
*/
#include <ch.h>
static WORKING_AREA(idle_thread_wa, IDLE_THREAD_STACK_SIZE);
/**
* @brief This function implements the idle thread infinite loop.
* @details The function puts the processor in the lowest power mode capable
* to serve interrupts.<br>
* The priority is internally set to the minimum system value so
* that this thread is executed only if there are no other ready
* threads in the system.
*
* @param[in] p the thread parameter, unused in this scenario
*/
static void idle_thread(void *p) {
while (TRUE) {
port_wait_for_interrupt();
IDLE_LOOP_HOOK();
}
}
/**
* @brief ChibiOS/RT initialization.
* @details After executing this function the current instructions stream
* becomes the main thread.
*
* @note Interrupts should be still disabled when @p chSysInit() is invoked
* and are internally enabled.
* @note The main thread is created with priority @p NORMALPRIO.
*/
void chSysInit(void) {
static Thread mainthread;
port_init();
scheduler_init();
vt_init();
#if CH_USE_HEAP
heap_init();
#endif
#if CH_DBG_ENABLE_TRACE
trace_init();
#endif
/*
* Now this instructions flow becomes the main thread.
*/
(currp = init_thread(&mainthread, NORMALPRIO))->p_state = PRCURR;
chSysEnable();
/*
* This thread has the lowest priority in the system, its role is just to
* serve interrupts in its context while keeping the lowest energy saving
* mode compatible with the system status.
*/
chThdCreateStatic(idle_thread_wa, sizeof(idle_thread_wa), IDLEPRIO,
(tfunc_t)idle_thread, NULL);
}
/**
* @brief Handles time ticks for round robin preemption and timer increments.
* @details Decrements the remaining time quantum of the running thread
* and preempts it when the quantum is used up. Increments system
* time and manages the timers.
*
* @note The frequency of the timer determines the system tick granularity and,
* together with the @p CH_TIME_QUANTUM macro, the round robin interval.
*/
void chSysTimerHandlerI(void) {
#if CH_USE_ROUNDROBIN
/* running thread has not used up quantum yet? */
if (rlist.r_preempt > 0)
/* decrement remaining quantum */
rlist.r_preempt--;
#endif
#if CH_DBG_THREADS_PROFILING
currp->p_time++;
#endif
chVTDoTickI();
}
#if CH_USE_NESTED_LOCKS && !CH_OPTIMIZE_SPEED
void chSysLock(void) {
chDbgAssert(currp->p_locks >= 0,
"chSysLock(), #1",
"negative nesting counter");
if (currp->p_locks++ == 0)
port_lock();
}
void chSysUnlock(void) {
chDbgAssert(currp->p_locks > 0,
"chSysUnlock(), #1",
"non-positive nesting counter");
if (--currp->p_locks == 0)
port_unlock();
}
#endif /* CH_USE_NESTED_LOCKS && !CH_OPTIMIZE_SPEED */
/** @} */
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