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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/>.
*/
/**
* @addtogroup Threads
* @{
*/
#include <ch.h>
#ifndef CH_OPTIMIZE_SPEED
/*
* Removes a Thread from a list and returns it.
* @param tp the pointer to the thread to be removed from the list
* @return the removed thread pointer
*/
Thread *dequeue(Thread *tp) {
tp->p_prev->p_next = tp->p_next;
tp->p_next->p_prev = tp->p_prev;
return tp;
}
/*
* Inserts a thread into a bi-directional list in FIFO order.
* @param tp the pointer to the thread to be inserted in the list
* @param tqp the pointer to the threads list header
*/
void enqueue(Thread *tp, ThreadsQueue *tqp) {
tp->p_next = (Thread *)tqp;
tp->p_prev = tqp->p_prev;
tqp->p_prev->p_next = tp;
tqp->p_prev = tp;
}
#endif /* CH_OPTIMIZE_SPEED */
/*
* Initializes a thread structure.
*/
void _InitThread(t_prio prio, t_tmode mode, Thread *tp) {
tp->p_flags = mode;
tp->p_prio = prio;
tp->p_rdymsg = RDY_OK;
#ifdef CH_USE_RT_SEMAPHORES
tp->p_rtcnt = 0;
tp->p_bakprio = prio;
#endif
#ifdef CH_USE_WAITEXIT
tp->p_waiting.p_next = (Thread *)&tp->p_waiting;
tp->p_waiting.p_prev = (Thread *)&tp->p_waiting;
#endif
#ifdef CH_USE_MESSAGES
tp->p_msgqueue.p_next = (Thread *)&tp->p_msgqueue;
tp->p_msgqueue.p_prev = (Thread *)&tp->p_msgqueue;
#endif
#ifdef CH_USE_EVENTS
tp->p_epending = 0;
#endif
#ifdef CH_USE_EXIT_EVENT
chEvtInit(&tp->p_exitesource);
#endif
}
/**
* Creates a new thread.
* @param prio the priority level for the new thread. Usually the threads are
* created with priority \p NORMALPRIO (128), priorities
* can range from \p LOWPRIO (1) to \p HIGHPRIO
* (255).
* @param mode the creation option flags for the thread. The following options
* can be OR'ed in this parameter:<br>
* <ul>
* <li>\p P_SUSPENDED, the thread is created in the
* \p PRSUSPENDED state and a subsequent call to
* \p chThdResume() will make it ready for
* execution.</li>
* <li>\p P_TERMINATED, this flag is usually set
* by the \p chThdTerminate() function and it is not
* normally used as parameter for this function. The
* result would be to create a thread with a termination
* request already pending.</li>
* </ul>
* @param workspace pointer to a working area dedicated to the thread stack
* @param wsize size of the working area.
* @param pf the thread function. Returning from this function automatically
* terminates the thread.
* @param arg an argument passed to the thread function. It can be \p NULL.
* @return the pointer to the \p Thread structure allocated for the
* thread into the working space area.
* @note A thread can terminate by calling \p chThdExit() or by simply
* returning from its main function.
*/
Thread *chThdCreate(t_prio prio, t_tmode mode, void *workspace,
t_size wsize, t_tfunc pf, void *arg) {
Thread *tp = workspace;
_InitThread(prio, mode, tp);
SETUP_CONTEXT(workspace, wsize, pf, arg);
#ifdef CH_USE_RESUME
if (tp->p_flags & P_SUSPENDED)
tp->p_state = PRSUSPENDED;
else {
#endif
chSysLock();
chSchWakeupI(tp, RDY_OK);
chSysUnlock();
#ifdef CH_USE_RESUME
}
#endif
return tp;
}
/**
* Verifies if the specified thread is in the \p PREXIT state.
* @param tp the pointer to the thread
* @return \p TRUE if the thread is ended else \p FALSE. \p TRUE ensures that
* a subsequent call to \p chThdWait() would not block.
*/
BOOL chThdTerminated(Thread *tp) {
return tp->p_state == PREXIT;
}
#ifdef CH_USE_RESUME
/**
* Resumes a thread created with the \p P_SUSPENDED option.
* @param tp the pointer to the thread
* @note The function has no effect on threads in any other state than
* \p PRSUSPENDED.
* @note The function is available only if the \p CH_USE_RESUME
* option is enabled in \p chconf.h.
*/
void chThdResume(Thread *tp) {
chSysLock();
if (tp->p_state == PRSUSPENDED)
chSchWakeupI(tp, RDY_OK);
chSysUnlock();
}
#endif
#ifdef CH_USE_TERMINATE
/**
* Requests a thread termination.
* @param tp the pointer to the thread
* @note The thread is not termitated but a termination request is added to
* its \p p_flags field. The thread can read this status by
* invoking \p chThdShouldTerminate() and then terminate cleanly.
*/
void chThdTerminate(Thread *tp) {
chSysLock();
tp->p_flags |= P_TERMINATE;
chSysUnlock();
}
/**
* Verifies if the current thread has a termination request pending.
* @return \p TRUE if the termination was requested. The thread should terminate
* as soon it is ready to do so.
*/
BOOL chThdShouldTerminate(void) {
return currp->p_flags & P_TERMINATE ? TRUE : FALSE;
}
#endif
/**
* Terminates the current thread by specifying an exit status code.
* @param msg the thread exit code. The code can be retrieved by using
* \p chThdWait().
*/
void chThdExit(t_msg msg) {
chSysLock();
currp->p_exitcode = msg; /* Post mortem info. */
#ifdef CH_USE_WAITEXIT
while (notempty(&currp->p_waiting))
chSchReadyI(dequeue(currp->p_waiting.p_next));
#endif
#ifdef CH_USE_EXIT_EVENT
chEvtSendI(&currp->p_exitesource);
#endif
chSchGoSleepI(PREXIT);
chSysUnlock(); /* Never executed. */
}
#ifdef CH_USE_WAITEXIT
/**
* Blocks the execution of the invoking thread until the specified thread
* terminates then the exit code is returned.
* @param tp the pointer to the thread
* @return the exit code
* @note The function is available only if the \p CH_USE_WAITEXIT
* option is enabled in \p chconf.h.
*/
t_msg chThdWait(Thread *tp) {
chSysLock();
if (tp->p_state != PREXIT) {
enqueue(currp, &tp->p_waiting);
chSchGoSleepI(PRWAIT);
}
chSysUnlock();
return tp->p_exitcode;
}
#endif /* CH_USE_WAITEXIT */
#ifdef CH_USE_EXIT_EVENT
/**
* Returns the exit event source for the specified thread. The source is
* signaled when the thread terminates.
* @param tp the pointer to the thread
* @note When registering on a thread termination make sure the thread
* is still alive, if you do that after the thread termination
* then you would miss the event. There are two ways to ensure
* this:<br>
* <ul>
* <li>Create the thread suspended, register on the event source
* and then resume the thread (recommended).</li>
* <li>Create the thread with a lower priority then register on it.
* This does not work if the hardware is capable of multiple
* physical threads.</li>
* </ul>
* @note You dont need to unregister from a terminated thread because
* the event source becomes inactive.
* @note The function is available only if the \p CH_USE_EXIT_EVENT
* option is enabled in \p chconf.h.
*/
EventSource *chThdGetExitEventSource(Thread *tp) {
return &tp->p_exitesource;
}
#endif /* CH_USE_EXIT_EVENT */
/** @} */
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