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/*
* Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "pico/mutex.h"
#include "pico/time.h"
#if !PICO_NO_HARDWARE
static_assert(sizeof(mutex_t) == 8, "");
#endif
void mutex_init(mutex_t *mtx) {
lock_init(&mtx->core, next_striped_spin_lock_num());
__mem_fence_release();
}
void __time_critical_func(mutex_enter_blocking)(mutex_t *mtx) {
assert(mtx->core.spin_lock);
bool block = true;
do {
uint32_t save = spin_lock_blocking(mtx->core.spin_lock);
if (!mtx->owned) {
mtx->owned = true;
mtx->owner = get_core_num();
block = false;
}
spin_unlock(mtx->core.spin_lock, save);
if (block) {
__wfe();
}
} while (block);
}
bool __time_critical_func(mutex_try_enter)(mutex_t *mtx, uint32_t *owner_out) {
bool entered;
uint32_t save = spin_lock_blocking(mtx->core.spin_lock);
if (!mtx->owned) {
mtx->owned = true;
mtx->owner = get_core_num();
entered = true;
} else {
if (owner_out) *owner_out = mtx->owner;
entered = false;
}
spin_unlock(mtx->core.spin_lock, save);
return entered;
}
bool __time_critical_func(mutex_enter_timeout_ms)(mutex_t *mtx, uint32_t timeout_ms) {
return mutex_enter_block_until(mtx, make_timeout_time_ms(timeout_ms));
}
bool __time_critical_func(mutex_enter_block_until)(mutex_t *mtx, absolute_time_t until) {
assert(mtx->core.spin_lock);
bool block = true;
do {
uint32_t save = spin_lock_blocking(mtx->core.spin_lock);
if (!mtx->owned) {
mtx->owned = true;
mtx->owner = get_core_num();
block = false;
}
spin_unlock(mtx->core.spin_lock, save);
if (block) {
if (best_effort_wfe_or_timeout(until)) {
return false;
}
}
} while (block);
return true;
}
void __time_critical_func(mutex_exit)(mutex_t *mtx) {
uint32_t save = spin_lock_blocking(mtx->core.spin_lock);
assert(mtx->owned);
mtx->owned = 0;
#ifndef NDEBUG
mtx->owner = -1;
#endif
__sev();
spin_unlock(mtx->core.spin_lock, save);
}
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