mutex.h

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/*
 * Copyright (c) 2015, Xilinx Inc. and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

 
#ifndef __METAL_MUTEX__H__
#error "Include metal/mutex.h instead of metal/generic/mutex.h"
#endif
 
#ifndef __METAL_GENERIC_MUTEX__H__
#define __METAL_GENERIC_MUTEX__H__
 
#include <metal/atomic.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
typedef struct {
        atomic_int v;
} metal_mutex_t;
 
#define METAL_MUTEX_UNLOCKED 0
#define METAL_MUTEX_LOCKED   1
 
/*
 * METAL_MUTEX_INIT - used for initializing an mutex element in a static struct
 * or global
 */
#define METAL_MUTEX_INIT(m) { ATOMIC_VAR_INIT(METAL_MUTEX_UNLOCKED) }
/*
 * METAL_MUTEX_DEFINE - used for defining and initializing a global or
 * static singleton mutex
 */
#define METAL_MUTEX_DEFINE(m) metal_mutex_t m = METAL_MUTEX_INIT(m)
 
static inline void __metal_mutex_init(metal_mutex_t *mutex)
{
        atomic_store(&mutex->v, METAL_MUTEX_UNLOCKED);
}
 
static inline void __metal_mutex_deinit(metal_mutex_t *mutex)
{
        (void)mutex;
}
 
static inline int __metal_mutex_try_acquire(metal_mutex_t *mutex)
{
        int unlocked = METAL_MUTEX_UNLOCKED;
 
        if (atomic_compare_exchange_strong(&mutex->v, &unlocked,
                                           METAL_MUTEX_LOCKED)) {
                return 1; /* acquired */
        } else {
                return 0; /* not acquired */
        }
}
 
static inline void __metal_mutex_acquire(metal_mutex_t *mutex)
{
        int unlocked = METAL_MUTEX_UNLOCKED;
 
        while (!atomic_compare_exchange_weak(&mutex->v, &unlocked,
                                             METAL_MUTEX_LOCKED)) {
                ;
        }
}
 
static inline void __metal_mutex_release(metal_mutex_t *mutex)
{
        atomic_store(&mutex->v, METAL_MUTEX_UNLOCKED);
}
 
static inline int __metal_mutex_is_acquired(metal_mutex_t *mutex)
{
        return atomic_load(&mutex->v);
}
 
#ifdef __cplusplus
}
#endif
 
#endif /* __METAL_GENERIC_MUTEX__H__ */