87 lines
3.0 KiB
C
87 lines
3.0 KiB
C
/* wait queue for multiple fibers on nanokernel objects */
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/*
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* Copyright (c) 2015 Wind River Systems, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1) Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2) Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3) Neither the name of Wind River Systems nor the names of its contributors
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* may be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _kernel_nanokernel_include_wait_q__h_
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#define _kernel_nanokernel_include_wait_q__h_
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#include <nanok.h>
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/* reset a wait queue, call during operation */
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static inline void _nano_wait_q_reset(struct _nano_queue *wait_q)
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{
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wait_q->head = (void *)0;
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wait_q->tail = (void *)&(wait_q->head);
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}
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/* initialize a wait queue: call only during object initialization */
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static inline void _nano_wait_q_init(struct _nano_queue *wait_q)
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{
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_nano_wait_q_reset(wait_q);
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}
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/*
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* Remove first fiber from a wait queue and put it on the ready queue, knowing
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* that the wait queue is not empty.
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*/
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static inline tCCS *_nano_wait_q_remove_no_check(struct _nano_queue *wait_q)
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{
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tCCS *ccs = wait_q->head;
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if (wait_q->tail == wait_q->head) {
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_nano_wait_q_reset(wait_q);
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} else {
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wait_q->head = ccs->link;
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}
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ccs->link = 0;
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_insert_ccs((tCCS **)&_nanokernel.fiber, ccs);
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return ccs;
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}
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/*
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* Remove first fiber from a wait queue and put it on the ready queue.
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* Abort and return NULL if the wait queue is empty.
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*/
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static inline tCCS *_nano_wait_q_remove(struct _nano_queue *wait_q)
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{
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return wait_q->head ? _nano_wait_q_remove_no_check(wait_q) : NULL;
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}
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/* put current fiber on specified wait queue */
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static inline void _nano_wait_q_put(struct _nano_queue *wait_q)
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{
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((tCCS *)wait_q->tail)->link = _nanokernel.current;
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wait_q->tail = _nanokernel.current;
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}
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#endif /* _kernel_nanokernel_include_wait_q__h_ */
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