blob: 1efa3dffd8bf65fe0fef137537becf119ac5b014 [file] [log] [blame]
// 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_thread/sleep.h"
#include <algorithm>
#include "FreeRTOS.h"
#include "pw_assert/check.h"
#include "pw_chrono/system_clock.h"
#include "pw_chrono_freertos/system_clock_constants.h"
#include "pw_thread/id.h"
#include "task.h"
using pw::chrono::SystemClock;
namespace pw::this_thread {
void sleep_for(SystemClock::duration sleep_duration) {
// Ensure this is being called by a thread.
PW_DCHECK(get_id() != thread::Id());
// Yield for negative and zero length durations.
if (sleep_duration <= SystemClock::duration::zero()) {
taskYIELD();
return;
}
// In case the timeout is too long for us to express through the native
// FreeRTOS API, we repeatedly wait with shorter durations. Note that on a
// tick based kernel we cannot tell how far along we are on the current tick,
// ergo we add one whole tick to the final duration. However, this also means
// that the loop must ensure that timeout + 1 is less than the max timeout.
constexpr SystemClock::duration kMaxTimeoutMinusOne =
pw::chrono::freertos::kMaxTimeout - SystemClock::duration(1);
while (sleep_duration > kMaxTimeoutMinusOne) {
vTaskDelay(static_cast<TickType_t>(kMaxTimeoutMinusOne.count()));
sleep_duration -= kMaxTimeoutMinusOne;
}
// On a tick based kernel we cannot tell how far along we are on the current
// tick, ergo we add one whole tick to the final duration.
vTaskDelay(static_cast<TickType_t>(sleep_duration.count() + 1));
}
} // namespace pw::this_thread