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Diffstat (limited to 'os/kernel/src/chsem.c')
| -rw-r--r-- | os/kernel/src/chsem.c | 393 |
1 files changed, 0 insertions, 393 deletions
diff --git a/os/kernel/src/chsem.c b/os/kernel/src/chsem.c deleted file mode 100644 index c9e429beb..000000000 --- a/os/kernel/src/chsem.c +++ /dev/null @@ -1,393 +0,0 @@ -/*
- ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
- 2011,2012,2013 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 chsem.c
- * @brief Semaphores code.
- *
- * @addtogroup semaphores
- * @details Semaphores related APIs and services.
- *
- * <h2>Operation mode</h2>
- * Semaphores are a flexible synchronization primitive, ChibiOS/RT
- * implements semaphores in their "counting semaphores" variant as
- * defined by Edsger Dijkstra plus several enhancements like:
- * - Wait operation with timeout.
- * - Reset operation.
- * - Atomic wait+signal operation.
- * - Return message from the wait operation (OK, RESET, TIMEOUT).
- * .
- * The binary semaphores variant can be easily implemented using
- * counting semaphores.<br>
- * Operations defined for semaphores:
- * - <b>Signal</b>: The semaphore counter is increased and if the
- * result is non-positive then a waiting thread is removed from
- * the semaphore queue and made ready for execution.
- * - <b>Wait</b>: The semaphore counter is decreased and if the result
- * becomes negative the thread is queued in the semaphore and
- * suspended.
- * - <b>Reset</b>: The semaphore counter is reset to a non-negative
- * value and all the threads in the queue are released.
- * .
- * Semaphores can be used as guards for mutual exclusion zones
- * (note that mutexes are recommended for this kind of use) but
- * also have other uses, queues guards and counters for example.<br>
- * Semaphores usually use a FIFO queuing strategy but it is possible
- * to make them order threads by priority by enabling
- * @p CH_USE_SEMAPHORES_PRIORITY in @p chconf.h.
- * @pre In order to use the semaphore APIs the @p CH_USE_SEMAPHORES
- * option must be enabled in @p chconf.h.
- * @{
- */
-
-#include "ch.h"
-
-#if CH_USE_SEMAPHORES || defined(__DOXYGEN__)
-
-#if CH_USE_SEMAPHORES_PRIORITY
-#define sem_insert(tp, qp) prio_insert(tp, qp)
-#else
-#define sem_insert(tp, qp) queue_insert(tp, qp)
-#endif
-
-/**
- * @brief Initializes a semaphore with the specified counter value.
- *
- * @param[out] sp pointer to a @p Semaphore structure
- * @param[in] n initial value of the semaphore counter. Must be
- * non-negative.
- *
- * @init
- */
-void chSemInit(Semaphore *sp, cnt_t n) {
-
- chDbgCheck((sp != NULL) && (n >= 0), "chSemInit");
-
- queue_init(&sp->s_queue);
- sp->s_cnt = n;
-}
-
-/**
- * @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 The released threads can recognize they were waked up by a reset
- * rather than a signal because the @p chSemWait() will return
- * @p RDY_RESET instead of @p RDY_OK.
- *
- * @param[in] sp pointer to a @p Semaphore structure
- * @param[in] n the new value of the semaphore counter. The value must
- * be non-negative.
- *
- * @api
- */
-void chSemReset(Semaphore *sp, cnt_t n) {
-
- chSysLock();
- chSemResetI(sp, n);
- chSchRescheduleS();
- chSysUnlock();
-}
-
-/**
- * @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 The released threads can recognize they were waked up by a reset
- * rather than a signal because the @p chSemWait() will return
- * @p RDY_RESET instead of @p RDY_OK.
- *
- * @param[in] sp pointer to a @p Semaphore structure
- * @param[in] n the new value of the semaphore counter. The value must
- * be non-negative.
- *
- * @iclass
- */
-void chSemResetI(Semaphore *sp, cnt_t n) {
- cnt_t cnt;
-
- chDbgCheckClassI();
- chDbgCheck((sp != NULL) && (n >= 0), "chSemResetI");
- chDbgAssert(((sp->s_cnt >= 0) && isempty(&sp->s_queue)) ||
- ((sp->s_cnt < 0) && notempty(&sp->s_queue)),
- "chSemResetI(), #1",
- "inconsistent semaphore");
-
- cnt = sp->s_cnt;
- sp->s_cnt = n;
- while (++cnt <= 0)
- chSchReadyI(lifo_remove(&sp->s_queue))->p_u.rdymsg = RDY_RESET;
-}
-
-/**
- * @brief Performs a wait operation on a semaphore.
- *
- * @param[in] sp pointer to a @p Semaphore structure
- * @return A message specifying how the invoking thread has been
- * released from the semaphore.
- * @retval RDY_OK if the thread has not stopped on the semaphore or the
- * semaphore has been signaled.
- * @retval RDY_RESET if the semaphore has been reset using @p chSemReset().
- *
- * @api
- */
-msg_t chSemWait(Semaphore *sp) {
- msg_t msg;
-
- chSysLock();
- msg = chSemWaitS(sp);
- chSysUnlock();
- return msg;
-}
-
-/**
- * @brief Performs a wait operation on a semaphore.
- *
- * @param[in] sp pointer to a @p Semaphore structure
- * @return A message specifying how the invoking thread has been
- * released from the semaphore.
- * @retval RDY_OK if the thread has not stopped on the semaphore or the
- * semaphore has been signaled.
- * @retval RDY_RESET if the semaphore has been reset using @p chSemReset().
- *
- * @sclass
- */
-msg_t chSemWaitS(Semaphore *sp) {
-
- chDbgCheckClassS();
- chDbgCheck(sp != NULL, "chSemWaitS");
- chDbgAssert(((sp->s_cnt >= 0) && isempty(&sp->s_queue)) ||
- ((sp->s_cnt < 0) && notempty(&sp->s_queue)),
- "chSemWaitS(), #1",
- "inconsistent semaphore");
-
- if (--sp->s_cnt < 0) {
- currp->p_u.wtobjp = sp;
- sem_insert(currp, &sp->s_queue);
- chSchGoSleepS(THD_STATE_WTSEM);
- return currp->p_u.rdymsg;
- }
- return RDY_OK;
-}
-
-/**
- * @brief Performs a wait operation on a semaphore with timeout specification.
- *
- * @param[in] sp pointer to a @p Semaphore structure
- * @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 A message specifying how the invoking thread has been
- * released from the semaphore.
- * @retval RDY_OK if the thread has not stopped on the semaphore or the
- * semaphore has been signaled.
- * @retval RDY_RESET if the semaphore has been reset using @p chSemReset().
- * @retval RDY_TIMEOUT if the semaphore has not been signaled or reset within
- * the specified timeout.
- *
- * @api
- */
-msg_t chSemWaitTimeout(Semaphore *sp, systime_t time) {
- msg_t msg;
-
- chSysLock();
- msg = chSemWaitTimeoutS(sp, time);
- chSysUnlock();
- return msg;
-}
-
-/**
- * @brief Performs a wait operation on a semaphore with timeout specification.
- *
- * @param[in] sp pointer to a @p Semaphore structure
- * @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 A message specifying how the invoking thread has been
- * released from the semaphore.
- * @retval RDY_OK if the thread has not stopped on the semaphore or the
- * semaphore has been signaled.
- * @retval RDY_RESET if the semaphore has been reset using @p chSemReset().
- * @retval RDY_TIMEOUT if the semaphore has not been signaled or reset within
- * the specified timeout.
- *
- * @sclass
- */
-msg_t chSemWaitTimeoutS(Semaphore *sp, systime_t time) {
-
- chDbgCheckClassS();
- chDbgCheck(sp != NULL, "chSemWaitTimeoutS");
- chDbgAssert(((sp->s_cnt >= 0) && isempty(&sp->s_queue)) ||
- ((sp->s_cnt < 0) && notempty(&sp->s_queue)),
- "chSemWaitTimeoutS(), #1",
- "inconsistent semaphore");
-
- if (--sp->s_cnt < 0) {
- if (TIME_IMMEDIATE == time) {
- sp->s_cnt++;
- return RDY_TIMEOUT;
- }
- currp->p_u.wtobjp = sp;
- sem_insert(currp, &sp->s_queue);
- return chSchGoSleepTimeoutS(THD_STATE_WTSEM, time);
- }
- return RDY_OK;
-}
-
-/**
- * @brief Performs a signal operation on a semaphore.
- *
- * @param[in] sp pointer to a @p Semaphore structure
- *
- * @api
- */
-void chSemSignal(Semaphore *sp) {
-
- chDbgCheck(sp != NULL, "chSemSignal");
- chDbgAssert(((sp->s_cnt >= 0) && isempty(&sp->s_queue)) ||
- ((sp->s_cnt < 0) && notempty(&sp->s_queue)),
- "chSemSignal(), #1",
- "inconsistent semaphore");
-
- chSysLock();
- if (++sp->s_cnt <= 0)
- chSchWakeupS(fifo_remove(&sp->s_queue), RDY_OK);
- chSysUnlock();
-}
-
-/**
- * @brief Performs a signal operation on a semaphore.
- * @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.
- *
- * @param[in] sp pointer to a @p Semaphore structure
- *
- * @iclass
- */
-void chSemSignalI(Semaphore *sp) {
-
- chDbgCheckClassI();
- chDbgCheck(sp != NULL, "chSemSignalI");
- chDbgAssert(((sp->s_cnt >= 0) && isempty(&sp->s_queue)) ||
- ((sp->s_cnt < 0) && notempty(&sp->s_queue)),
- "chSemSignalI(), #1",
- "inconsistent semaphore");
-
- if (++sp->s_cnt <= 0) {
- /* Note, it is done this way in order to allow a tail call on
- chSchReadyI().*/
- Thread *tp = fifo_remove(&sp->s_queue);
- tp->p_u.rdymsg = RDY_OK;
- chSchReadyI(tp);
- }
-}
-
-/**
- * @brief Adds the specified value to the semaphore counter.
- * @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.
- *
- * @param[in] sp pointer to a @p Semaphore structure
- * @param[in] n value to be added to the semaphore counter. The value
- * must be positive.
- *
- * @iclass
- */
-void chSemAddCounterI(Semaphore *sp, cnt_t n) {
-
- chDbgCheckClassI();
- chDbgCheck((sp != NULL) && (n > 0), "chSemAddCounterI");
- chDbgAssert(((sp->s_cnt >= 0) && isempty(&sp->s_queue)) ||
- ((sp->s_cnt < 0) && notempty(&sp->s_queue)),
- "chSemAddCounterI(), #1",
- "inconsistent semaphore");
-
- while (n > 0) {
- if (++sp->s_cnt <= 0)
- chSchReadyI(fifo_remove(&sp->s_queue))->p_u.rdymsg = RDY_OK;
- n--;
- }
-}
-
-#if CH_USE_SEMSW || defined(__DOXYGEN__)
-/**
- * @brief Performs atomic signal and wait operations on two semaphores.
- * @pre The configuration option @p CH_USE_SEMSW must be enabled in order
- * to use this function.
- *
- * @param[in] sps pointer to a @p Semaphore structure to be signaled
- * @param[in] spw pointer to a @p Semaphore structure to wait on
- * @return A message specifying how the invoking thread has been
- * released from the semaphore.
- * @retval RDY_OK if the thread has not stopped on the semaphore or the
- * semaphore has been signaled.
- * @retval RDY_RESET if the semaphore has been reset using @p chSemReset().
- *
- * @api
- */
-msg_t chSemSignalWait(Semaphore *sps, Semaphore *spw) {
- msg_t msg;
-
- chDbgCheck((sps != NULL) && (spw != NULL), "chSemSignalWait");
- chDbgAssert(((sps->s_cnt >= 0) && isempty(&sps->s_queue)) ||
- ((sps->s_cnt < 0) && notempty(&sps->s_queue)),
- "chSemSignalWait(), #1",
- "inconsistent semaphore");
- chDbgAssert(((spw->s_cnt >= 0) && isempty(&spw->s_queue)) ||
- ((spw->s_cnt < 0) && notempty(&spw->s_queue)),
- "chSemSignalWait(), #2",
- "inconsistent semaphore");
-
- chSysLock();
- if (++sps->s_cnt <= 0)
- chSchReadyI(fifo_remove(&sps->s_queue))->p_u.rdymsg = RDY_OK;
- if (--spw->s_cnt < 0) {
- Thread *ctp = currp;
- sem_insert(ctp, &spw->s_queue);
- ctp->p_u.wtobjp = spw;
- chSchGoSleepS(THD_STATE_WTSEM);
- msg = ctp->p_u.rdymsg;
- }
- else {
- chSchRescheduleS();
- msg = RDY_OK;
- }
- chSysUnlock();
- return msg;
-}
-#endif /* CH_USE_SEMSW */
-
-#endif /* CH_USE_SEMAPHORES */
-
-/** @} */
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