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/* SPDX-License-Identifier: BSD-3-Clause
* Copyright (c) 2014-2018 Linaro Limited
* Copyright (c) 2022 Nokia
*/
#ifndef ODP_PLAT_RWLOCK_INLINES_H_
#define ODP_PLAT_RWLOCK_INLINES_H_
#include <odp/api/atomic.h>
#include <odp/api/cpu.h>
#include <odp/api/abi/rwlock.h>
#include <stdint.h>
/** @cond _ODP_HIDE_FROM_DOXYGEN_ */
#ifndef _ODP_NO_INLINE
/* Inline functions by default */
#define _ODP_INLINE static inline
#define odp_rwlock_init __odp_rwlock_init
#define odp_rwlock_read_lock __odp_rwlock_read_lock
#define odp_rwlock_read_trylock __odp_rwlock_read_trylock
#define odp_rwlock_read_unlock __odp_rwlock_read_unlock
#define odp_rwlock_write_lock __odp_rwlock_write_lock
#define odp_rwlock_write_trylock __odp_rwlock_write_trylock
#define odp_rwlock_write_unlock __odp_rwlock_write_unlock
#else
#undef _ODP_INLINE
#define _ODP_INLINE
#endif
_ODP_INLINE void odp_rwlock_init(odp_rwlock_t *rwlock)
{
odp_atomic_init_u32(&rwlock->cnt, 0);
}
_ODP_INLINE void odp_rwlock_read_lock(odp_rwlock_t *rwlock)
{
uint32_t cnt;
int is_locked = 0;
while (is_locked == 0) {
cnt = odp_atomic_load_u32(&rwlock->cnt);
/* waiting for read lock */
if ((int32_t)cnt < 0) {
odp_cpu_pause();
continue;
}
is_locked = odp_atomic_cas_acq_u32(&rwlock->cnt, &cnt, cnt + 1);
}
}
_ODP_INLINE int odp_rwlock_read_trylock(odp_rwlock_t *rwlock)
{
uint32_t cnt = odp_atomic_load_u32(&rwlock->cnt);
while (cnt != (uint32_t)-1) {
if (odp_atomic_cas_acq_u32(&rwlock->cnt, &cnt, cnt + 1))
return 1;
}
return 0;
}
_ODP_INLINE void odp_rwlock_read_unlock(odp_rwlock_t *rwlock)
{
odp_atomic_sub_rel_u32(&rwlock->cnt, 1);
}
_ODP_INLINE void odp_rwlock_write_lock(odp_rwlock_t *rwlock)
{
uint32_t cnt;
int is_locked = 0;
while (is_locked == 0) {
uint32_t zero = 0;
cnt = odp_atomic_load_u32(&rwlock->cnt);
/* lock acquired, wait */
if (cnt != 0) {
odp_cpu_pause();
continue;
}
is_locked = odp_atomic_cas_acq_u32(&rwlock->cnt, &zero, (uint32_t)-1);
}
}
_ODP_INLINE int odp_rwlock_write_trylock(odp_rwlock_t *rwlock)
{
uint32_t zero = 0;
return odp_atomic_cas_acq_u32(&rwlock->cnt, &zero, (uint32_t)-1);
}
_ODP_INLINE void odp_rwlock_write_unlock(odp_rwlock_t *rwlock)
{
odp_atomic_store_rel_u32(&rwlock->cnt, 0);
}
/** @endcond */
#endif
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