193 lines
4.5 KiB
C
193 lines
4.5 KiB
C
/*
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* Copyright (c) 1997-2010, 2012-2014 Wind River Systems, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* @file
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*
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*@brief Microkernel semaphore header file.
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*/
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#ifndef _SEMAPHORE_H
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#define _SEMAPHORE_H
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/**
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* @brief Microkernel Semaphores
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* @defgroup microkernel_semaphore Microkernel Semaphores
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* @ingroup microkernel_services
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* @{
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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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#include <microkernel/base_api.h>
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extern void _k_sem_struct_value_update(int n, struct _k_sem_struct *S);
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/*
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* Initializer for semaphore
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*/
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#define __K_SEMAPHORE_DEFAULT \
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{ \
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.waiters = NULL, \
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.level = 0, \
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.count = 0, \
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}
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/**
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*
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* @brief Give semaphore (from an ISR).
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*
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* This routine gives semaphore @a sema from an ISR, rather than a task.
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*
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* @param sema Semaphore name.
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*
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* @return N/A
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*/
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extern void isr_sem_give(ksem_t sema);
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/**
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*
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* @brief Give semaphore (from a fiber).
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*
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* This routine gives semaphore @a sema from a fiber, rather than a task.
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*
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* @param sema Semaphore name.
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*
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* @return N/A
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*/
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extern void fiber_sem_give(ksem_t sema);
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/**
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*
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* @brief Give semaphore.
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*
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* This routine gives semaphore @a sema.
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*
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* @param sema Semaphore name.
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*
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* @return N/A
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*/
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extern void task_sem_give(ksem_t sema);
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/**
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*
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* @brief Give a group of semaphores.
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*
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* This routine gives each semaphore in sempahore group @a semagroup.
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* This method is faster than giving the semaphores individually, and
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* ensures that all the semaphores are given before any waiting tasks run.
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*
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* @param semagroup Array of semaphore names, terminated by ENDLIST.
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*
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* @return N/A
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*/
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extern void task_sem_group_give(ksemg_t semagroup);
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/**
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*
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* @brief Read a semaphore's count.
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*
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* This routine reads the current count of semaphore @a sema.
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*
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* @param sema Semaphore name.
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*
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* @return Semaphore count.
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*/
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extern int task_sem_count_get(ksem_t sema);
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/**
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*
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* @brief Reset semaphore count.
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*
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* This routine resets the count of semaphore @a sema to zero.
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*
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* @param sema Semaphore name.
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*
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* @return N/A
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*/
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extern void task_sem_reset(ksem_t sema);
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/**
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*
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* @brief Reset a group of semaphores
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*
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* This routine resets the count for each semaphore in sempahore group
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* @a semagroup to zero. This method is faster than resetting the semaphores
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* individually.
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*
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* @param semagroup Array of semaphore names, terminated by ENDLIST.
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*
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* @return N/A
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*/
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extern void task_sem_group_reset(ksemg_t semagroup);
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/**
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*
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* @brief Take semaphore or fail.
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*
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* This routine takes semaphore @a sema. If the semaphore's count is zero the
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* routine immediately returns a failure indication.
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*
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* @param sema Semaphore name.
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* @param timeout Affects the action taken should the semaphore be unavailable.
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* If TICKS_NONE, then return immediately. If TICKS_UNLIMITED, then wait as
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* long as necessary. Otherwise wait up to the specified number of ticks before
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* timing out.
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*
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* @retval RC_OK Successfully took semaphore
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* @retval RC_TIME Timed out while waiting for semaphore
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* @retval RC_FAIL Failed to immediately take semaphore when
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* @a timeout = TICKS_NONE
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*/
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extern int task_sem_take(ksem_t sema, int32_t timeout);
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/**
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*
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* @brief Wait for a semaphore from the semaphore group
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*
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* This routine waits up to @a timeout ticks to take a semaphore from the
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* semaphore group @a group.
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*
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* @param group Array of semaphore names, terminated by ENDLIST.
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* @param timeout Affects the action taken should no semaphore be available.
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* If TICKS_NONE, then return immediately. If TICKS_UNLIMITED, then wait
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* as long as necessary. Otherwise wait up to the specified number of ticks
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* before timing out.
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*
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* @return Name of semaphore that was taken if successful, else ENDLIST
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*/
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extern ksem_t task_sem_group_take(ksemg_t group, int32_t timeout);
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/**
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* @brief Define a private microkernel semaphore
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*
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* @param name Semaphore name.
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*/
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#define DEFINE_SEMAPHORE(name) \
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struct _k_sem_struct _k_sem_obj_##name = __K_SEMAPHORE_DEFAULT; \
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const ksem_t name = (ksem_t)&_k_sem_obj_##name;
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#ifdef __cplusplus
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}
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#endif
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/**
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* @}
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*/
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#endif /* _SEMAPHORE_H */
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