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https://github.com/OpenAMP/libmetal.git
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d3a27c1454
- start by "/**", - fix file relative path, - fix typos, Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
76 lines
1.8 KiB
C
76 lines
1.8 KiB
C
/*
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* Copyright (c) 2016, Xilinx Inc. and Contributors. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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/**
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* @file linux/condition.h
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* @brief Linux condition variable primitives for libmetal.
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*/
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#ifndef __METAL_CONDITION__H__
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#error "Include metal/condition.h instead of metal/linux/condition.h"
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#endif
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#ifndef __METAL_LINUX_CONDITION__H__
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#define __METAL_LINUX_CONDITION__H__
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#include <unistd.h>
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#include <sys/syscall.h>
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#include <linux/futex.h>
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#include <metal/atomic.h>
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#include <metal/errno.h>
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#include <stdint.h>
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#include <limits.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct metal_condition {
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atomic_uintptr_t mptr; /**< mutex pointer.
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* The condition variable is attached to
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* this mutex when it is waiting.
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* It is also used to check correctness
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* in case there are multiple waiters.
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*/
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atomic_int waiters; /**< number of waiters. */
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atomic_int wakeups; /**< number of wakeups. */
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};
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/** Static metal condition variable initialization. */
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#define METAL_CONDITION_INIT { ATOMIC_VAR_INIT(0), ATOMIC_VAR_INIT(0), \
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ATOMIC_VAR_INIT(0) }
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static inline void metal_condition_init(struct metal_condition *cv)
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{
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atomic_init(&cv->mptr, 0);
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atomic_init(&cv->waiters, 0);
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atomic_init(&cv->wakeups, 0);
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}
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static inline int metal_condition_signal(struct metal_condition *cv)
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{
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if (!cv)
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return -EINVAL;
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atomic_fetch_add(&cv->wakeups, 1);
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if (atomic_load(&cv->waiters) > 0)
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syscall(SYS_futex, &cv->wakeups, FUTEX_WAKE, 1, NULL, NULL, 0);
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return 0;
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}
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static inline int metal_condition_broadcast(struct metal_condition *cv)
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{
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if (!cv)
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return -EINVAL;
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atomic_fetch_add(&cv->wakeups, 1);
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if (atomic_load(&cv->waiters) > 0)
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syscall(SYS_futex, &cv->wakeups, FUTEX_WAKE, INT_MAX, NULL, NULL, 0);
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return 0;
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}
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#endif /* __METAL_LINUX_CONDITION__H__ */
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