| // 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/interrupt_spin_lock.h" |
| |
| #include "pw_assert/check.h" |
| #include "pw_interrupt/context.h" |
| #include "task.h" |
| |
| namespace pw::sync { |
| |
| #if (INCLUDE_xTaskGetSchedulerState != 1) && (configUSE_TIMERS != 1) |
| #error "xTaskGetSchedulerState is required for pw::sync::InterruptSpinLock" |
| #endif |
| |
| void InterruptSpinLock::lock() { |
| if (interrupt::InInterruptContext()) { |
| native_type_.saved_interrupt_mask = taskENTER_CRITICAL_FROM_ISR(); |
| } else { // Task context |
| // Suspending the scheduler ensures that kernel API calls that occur |
| // within the critical section will not preempt the current task |
| // (if called from a thread context). Otherwise, kernel APIs called |
| // from within the critical section may preempt the running task if |
| // the port implements portYIELD synchronously. |
| // Note: calls to vTaskSuspendAll(), like taskENTER_CRITICAL() can |
| // be nested. |
| // Note: vTaskSuspendAll()/xTaskResumeAll() are not safe to call before the |
| // scheduler has been started. |
| if (xTaskGetSchedulerState() != taskSCHEDULER_NOT_STARTED) { |
| vTaskSuspendAll(); |
| } |
| taskENTER_CRITICAL(); |
| } |
| // We can't deadlock here so crash instead. |
| PW_DCHECK(!native_type_.locked, |
| "Recursive InterruptSpinLock::lock() detected"); |
| native_type_.locked = true; |
| } |
| |
| void InterruptSpinLock::unlock() { |
| native_type_.locked = false; |
| if (interrupt::InInterruptContext()) { |
| taskEXIT_CRITICAL_FROM_ISR(native_type_.saved_interrupt_mask); |
| } else { // Task context |
| taskEXIT_CRITICAL(); |
| if (xTaskGetSchedulerState() != taskSCHEDULER_NOT_STARTED) { |
| xTaskResumeAll(); |
| } |
| } |
| } |
| |
| } // namespace pw::sync |