1 // Copyright 2021 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 #pragma once 15 16 #include <zephyr/kernel.h> 17 18 #include "pw_assert/assert.h" 19 #include "pw_chrono/system_clock.h" 20 #include "pw_interrupt/context.h" 21 #include "pw_sync/binary_semaphore.h" 22 23 namespace pw::sync { 24 BinarySemaphore()25inline BinarySemaphore::BinarySemaphore() : native_type_() { 26 constexpr unsigned int kInitialCount = 0; 27 k_sem_init(&native_type_, kInitialCount, backend::kBinarySemaphoreMaxValue); 28 } 29 30 inline BinarySemaphore::~BinarySemaphore() = default; 31 release()32inline void BinarySemaphore::release() { 33 PW_DASSERT(!interrupt::InInterruptContext()); 34 k_sem_give(&native_type_); 35 } 36 acquire()37inline void BinarySemaphore::acquire() { 38 PW_DASSERT(!interrupt::InInterruptContext()); 39 PW_ASSERT(k_sem_take(&native_type_, K_FOREVER) == 0); 40 } 41 try_acquire()42inline bool BinarySemaphore::try_acquire() noexcept { 43 return k_sem_take(&native_type_, K_NO_WAIT) == 0; 44 } 45 try_acquire_until(chrono::SystemClock::time_point deadline)46inline bool BinarySemaphore::try_acquire_until( 47 chrono::SystemClock::time_point deadline) { 48 // Note that if this deadline is in the future, it will get rounded up by 49 // one whole tick due to how try_acquire_for is implemented. 50 return try_acquire_for(deadline - chrono::SystemClock::now()); 51 } 52 native_handle()53inline BinarySemaphore::native_handle_type BinarySemaphore::native_handle() { 54 return native_type_; 55 } 56 57 } // namespace pw::sync 58