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semaphore.c
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semaphore.c
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/* SPDX-License-Identifier: BSD-3-Clause */
/*
* Copyright (c) 2019, NEC Laboratories Europe GmbH, NEC Corporation.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <uk/semaphore.h>
#include <uk/arch/time.h>
#include <lwip/sys.h>
#include <uk/essentials.h>
/**
* Initializes a new semaphore. The "count" argument specifies
* the initial state of the semaphore.
*/
err_t sys_sem_new(sys_sem_t *sem, u8_t count)
{
uk_semaphore_init(&sem->sem, (long) count);
sem->valid = 1;
return ERR_OK;
}
int sys_sem_valid(sys_sem_t *sem)
{
return (sem->valid == 1);
}
void sys_sem_set_invalid(sys_sem_t *sem)
{
sem->valid = 0;
}
void sys_sem_free(sys_sem_t *sem)
{
sys_sem_set_invalid(sem);
}
/* Signals a semaphore. */
void sys_sem_signal(sys_sem_t *sem)
{
uk_semaphore_up(&sem->sem);
}
/**
* Blocks the thread while waiting for the semaphore to be
* signaled. If the "timeout" argument is non-zero, the thread should
* only be blocked for the specified time (measured in
* milliseconds).
*
* If the timeout argument is non-zero, the return value is the number of
* milliseconds spent waiting for the semaphore to be signaled. If the
* semaphore wasn't signaled within the specified time, the return value is
* SYS_ARCH_TIMEOUT. If the thread didn't have to wait for the semaphore
* (i.e., it was already signaled), the function may return zero.
*/
u32_t sys_arch_sem_wait(sys_sem_t *sem, u32_t timeout)
{
__nsec nsret;
uk_pr_debug("sys_arch_sem_wait(%p, %"PRIu32")\n", sem, timeout);
if (timeout == 0) {
nsret = ukplat_monotonic_clock();
uk_semaphore_down(&sem->sem);
nsret = ukplat_monotonic_clock() - nsret;
} else {
nsret = uk_semaphore_down_to(&sem->sem,
ukarch_time_msec_to_nsec((__nsec)
timeout));
if (unlikely(nsret == __NSEC_MAX))
return SYS_ARCH_TIMEOUT;
}
return (u32_t) ukarch_time_nsec_to_msec(nsret);
}