219 lines
7.0 KiB
C
219 lines
7.0 KiB
C
/*
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ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
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2011,2012,2013 Giovanni Di Sirio.
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This file is part of ChibiOS/RT.
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ChibiOS/RT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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ChibiOS/RT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file chschd.h
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* @brief Scheduler macros and structures.
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*
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* @addtogroup scheduler
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* @{
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*/
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#ifndef _CHSCHD_H_
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#define _CHSCHD_H_
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/*===========================================================================*/
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/* Module constants. */
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/*===========================================================================*/
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/**
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* @name Wakeup status codes
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* @{
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*/
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#define MSG_OK 0 /**< @brief Normal wakeup message. */
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#define MSG_TIMEOUT -1 /**< @brief Wakeup caused by a timeout
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condition. */
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#define MSG_RESET -2 /**< @brief Wakeup caused by a reset
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condition. */
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/** @} */
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/**
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* @name Priority constants
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* @{
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*/
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#define NOPRIO 0 /**< @brief Ready list header priority. */
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#define IDLEPRIO 1 /**< @brief Idle thread priority. */
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#define LOWPRIO 2 /**< @brief Lowest user priority. */
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#define NORMALPRIO 64 /**< @brief Normal user priority. */
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#define HIGHPRIO 127 /**< @brief Highest user priority. */
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#define ABSPRIO 255 /**< @brief Greatest possible priority. */
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/** @} */
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/**
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* @name Special time constants
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* @{
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*/
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/**
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* @brief Zero time specification for some functions with a timeout
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* specification.
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* @note Not all functions accept @p TIME_IMMEDIATE as timeout parameter,
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* see the specific function documentation.
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*/
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#define TIME_IMMEDIATE ((systime_t)0)
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/**
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* @brief Infinite time specification for all functions with a timeout
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* specification.
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*/
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#define TIME_INFINITE ((systime_t)-1)
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/** @} */
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/*===========================================================================*/
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/* Module pre-compile time settings. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Derived constants and error checks. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Module data structures and types. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Module macros. */
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/*===========================================================================*/
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/**
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* @brief Returns the priority of the first thread on the given ready list.
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*
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* @notapi
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*/
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#define firstprio(rlp) ((rlp)->p_next->p_prio)
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/**
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* @brief Current thread pointer access macro.
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* @note This macro is not meant to be used in the application code but
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* only from within the kernel, use the @p chThdSelf() API instead.
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* @note It is forbidden to use this macro in order to change the pointer
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* (currp = something), use @p setcurrp() instead.
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*/
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#define currp ch.rlist.r_current
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/**
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* @brief Current thread pointer change macro.
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* @note This macro is not meant to be used in the application code but
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* only from within the kernel.
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*
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* @notapi
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*/
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#define setcurrp(tp) (currp = (tp))
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/*===========================================================================*/
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/* External declarations. */
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/*===========================================================================*/
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/*
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* Scheduler APIs.
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*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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void _scheduler_init(void);
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thread_t *chSchReadyI(thread_t *tp);
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void chSchGoSleepS(tstate_t newstate);
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msg_t chSchGoSleepTimeoutS(tstate_t newstate, systime_t time);
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void chSchWakeupS(thread_t *tp, msg_t msg);
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void chSchRescheduleS(void);
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bool chSchIsPreemptionRequired(void);
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void chSchDoRescheduleBehind(void);
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void chSchDoRescheduleAhead(void);
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void chSchDoReschedule(void);
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#ifdef __cplusplus
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}
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#endif
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/*===========================================================================*/
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/* Module inline functions. */
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/*===========================================================================*/
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/**
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* @brief Determines if the current thread must reschedule.
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* @details This function returns @p true if there is a ready thread with
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* higher priority.
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*
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* @iclass
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*/
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static inline bool chSchIsRescRequiredI(void) {
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chDbgCheckClassI();
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return firstprio(&ch.rlist.r_queue) > currp->p_prio;
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}
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/**
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* @brief Determines if yielding is possible.
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* @details This function returns @p true if there is a ready thread with
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* equal or higher priority.
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*
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* @sclass
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*/
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static inline bool chSchCanYieldS(void) {
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chDbgCheckClassI();
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return firstprio(&ch.rlist.r_queue) >= currp->p_prio;
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}
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/**
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* @brief Yields the time slot.
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* @details Yields the CPU control to the next thread in the ready list with
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* equal or higher priority, if any.
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*
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* @sclass
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*/
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static inline void chSchDoYieldS(void) {
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chDbgCheckClassS();
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if (chSchCanYieldS())
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chSchDoRescheduleBehind();
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}
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/**
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* @brief Inline-able preemption code.
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* @details This is the common preemption code, this function must be invoked
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* exclusively from the port layer.
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*
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* @special
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*/
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static inline void chSchPreemption(void) {
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tprio_t p1 = firstprio(&ch.rlist.r_queue);
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tprio_t p2 = currp->p_prio;
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#if CH_CFG_TIME_QUANTUM > 0
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if (currp->p_preempt) {
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if (p1 > p2)
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chSchDoRescheduleAhead();
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}
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else {
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if (p1 >= p2)
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chSchDoRescheduleBehind();
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}
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#else /* CH_CFG_TIME_QUANTUM == 0 */
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if (p1 >= p2)
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chSchDoRescheduleAhead();
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#endif /* CH_CFG_TIME_QUANTUM == 0 */
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}
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#endif /* _CHSCHD_H_ */
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/** @} */
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