| // 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/light.h" |
| #include "pw_chrono/system_clock.h" |
| #include "pw_chrono_freertos/system_clock_constants.h" |
| #include "pw_interrupt/context.h" |
| #include "pw_sync/mutex.h" |
| #include "semphr.h" |
| |
| namespace pw::sync { |
| |
| inline Mutex::Mutex() : native_type_() { |
| const SemaphoreHandle_t handle = xSemaphoreCreateMutexStatic(&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 == &native_type_); |
| } |
| |
| inline Mutex::~Mutex() { vSemaphoreDelete(&native_type_); } |
| |
| inline void Mutex::lock() { |
| PW_ASSERT(!interrupt::InInterruptContext()); |
| #if INCLUDE_vTaskSuspend == 1 // This means portMAX_DELAY is indefinite. |
| const BaseType_t result = xSemaphoreTake(&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(&native_type_, chrono::freertos::kMaxTimeout.count()) == |
| pdFALSE) { |
| } |
| #endif // INCLUDE_vTaskSuspend |
| } |
| |
| inline bool Mutex::try_lock() { |
| PW_ASSERT(!interrupt::InInterruptContext()); |
| return xSemaphoreTake(&native_type_, 0) == pdTRUE; |
| } |
| |
| inline bool Mutex::try_lock_until( |
| chrono::SystemClock::time_point until_at_least) { |
| // Note that if this deadline is in the future, it will get rounded up by |
| // one whole tick due to how try_lock_for is implemented. |
| return try_lock_for(until_at_least - chrono::SystemClock::now()); |
| } |
| |
| inline void Mutex::unlock() { |
| PW_ASSERT(!interrupt::InInterruptContext()); |
| // Unlocking only fails if it was not locked first. |
| PW_ASSERT(xSemaphoreGive(&native_type_) == pdTRUE); |
| } |
| |
| inline Mutex::native_handle_type Mutex::native_handle() { return native_type_; } |
| |
| } // namespace pw::sync |