| // 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. |
| |
| #include "pw_sync/binary_semaphore.h" |
| |
| #include <algorithm> |
| |
| #include "pw_assert/assert.h" |
| #include "pw_chrono/system_clock.h" |
| #include "pw_chrono_threadx/system_clock_constants.h" |
| #include "pw_interrupt/context.h" |
| #include "tx_api.h" |
| |
| using pw::chrono::SystemClock; |
| using pw::chrono::threadx::kMaxTimeout; |
| |
| namespace pw::sync { |
| |
| bool BinarySemaphore::try_acquire_for(SystemClock::duration for_at_least) { |
| // Enforce the pw::sync::BinarySemaphore IRQ contract. |
| PW_DCHECK(!interrupt::InInterruptContext()); |
| |
| // Clamp negative durations to be 0 which maps to non-blocking. |
| for_at_least = std::max(for_at_least, SystemClock::duration::zero()); |
| |
| while (for_at_least > kMaxTimeout) { |
| const UINT result = tx_semaphore_get(&native_type_, kMaxTimeout.count()); |
| if (result != TX_NO_INSTANCE) { |
| // If we didn't time out (TX_NO_INSTANCE), then we should have succeeded. |
| PW_CHECK_UINT_EQ(TX_SUCCESS, result); |
| return true; |
| } |
| for_at_least -= kMaxTimeout; |
| } |
| |
| const UINT result = tx_semaphore_get(&native_type_, for_at_least.count()); |
| if (result == TX_NO_INSTANCE) { |
| return false; // We timed out, there's still no token. |
| } |
| PW_CHECK_UINT_EQ(TX_SUCCESS, result); |
| return true; |
| } |
| |
| } // namespace pw::sync |