| // Copyright 2020 The Pigweed Authors |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); you may not |
| // use this file except in compliance with the License. You may obtain a copy of |
| // the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| // License for the specific language governing permissions and limitations under |
| // the License. |
| #pragma once |
| |
| #include "FreeRTOS.h" |
| #include "pw_assert/assert.h" |
| #include "pw_chrono/system_clock.h" |
| #include "pw_chrono_freertos/system_clock_constants.h" |
| #include "pw_interrupt/context.h" |
| #include "pw_sync/counting_semaphore.h" |
| #include "semphr.h" |
| |
| namespace pw::sync { |
| |
| inline CountingSemaphore::CountingSemaphore() : native_type_() { |
| const SemaphoreHandle_t handle = |
| xSemaphoreCreateCountingStatic(max(), 0, &native_type_); |
| // This should never fail since the pointer provided was not null and it |
| // should return a pointer to the StaticSemaphore_t. |
| PW_DASSERT(handle == reinterpret_cast<SemaphoreHandle_t>(&native_type_)); |
| } |
| |
| inline CountingSemaphore::~CountingSemaphore() { |
| vSemaphoreDelete(reinterpret_cast<SemaphoreHandle_t>(&native_type_)); |
| } |
| |
| inline void CountingSemaphore::acquire() { |
| // Enforce the pw::sync::CountingSemaphore IRQ contract. |
| PW_DASSERT(!interrupt::InInterruptContext()); |
| #if INCLUDE_vTaskSuspend == 1 // This means portMAX_DELAY is indefinite. |
| const BaseType_t result = xSemaphoreTake( |
| reinterpret_cast<SemaphoreHandle_t>(&native_type_), portMAX_DELAY); |
| PW_DASSERT(result == pdTRUE); |
| #else |
| // In case we need to block for longer than the FreeRTOS delay can represent |
| // repeatedly hit take until success. |
| while (xSemaphoreTake(reinterpret_cast<SemaphoreHandle_t>(&native_type_), |
| chrono::freertos::kMaxTimeout.count()) == pdFALSE) { |
| } |
| #endif // INCLUDE_vTaskSuspend |
| } |
| |
| inline bool CountingSemaphore::try_acquire() noexcept { |
| if (interrupt::InInterruptContext()) { |
| BaseType_t woke_higher_task = pdFALSE; |
| const bool success = xSemaphoreTakeFromISR( |
| reinterpret_cast<SemaphoreHandle_t>(&native_type_), |
| &woke_higher_task) == pdTRUE; |
| portYIELD_FROM_ISR(woke_higher_task); |
| return success; |
| } |
| |
| // Task Context |
| return xSemaphoreTake(reinterpret_cast<SemaphoreHandle_t>(&native_type_), |
| 0) == pdTRUE; |
| } |
| |
| inline bool CountingSemaphore::try_acquire_until( |
| chrono::SystemClock::time_point deadline) { |
| // Note that if this deadline is in the future, it will get rounded up by |
| // one whole tick due to how try_acquire_for is implemented. |
| return try_acquire_for(deadline - chrono::SystemClock::now()); |
| } |
| |
| inline CountingSemaphore::native_handle_type |
| CountingSemaphore::native_handle() { |
| return native_type_; |
| } |
| |
| } // namespace pw::sync |