unplugged-system/system/chre/platform/embos/system_timer.cc

88 lines
2.8 KiB
C++

/*
* Copyright (C) 2022 The Android Open Source Project
*
* 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
*
* http://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 <algorithm>
#include <cinttypes>
#include "chre/platform/fatal_error.h"
#include "chre/platform/log.h"
#include "chre/platform/system_timer.h"
#include "chre/util/time.h"
namespace chre {
void SystemTimerBase::invokeCallback(void *instance) {
auto *timer = static_cast<SystemTimer *>(instance);
timer->mCallback(timer->mData);
}
SystemTimer::SystemTimer() {}
SystemTimer::~SystemTimer() {
// cancel an existing timer if any, and delete the timer instance.
cancel();
OS_DeleteTimerEx(&mTimer);
}
bool SystemTimer::init() {
constexpr uint32_t kSomeInitialPeriod = 100;
OS_CreateTimerEx(&mTimer, SystemTimerBase::invokeCallback, kSomeInitialPeriod,
this /*context*/);
return true;
}
bool SystemTimer::set(SystemTimerCallback *callback, void *data,
Nanoseconds delay) {
// The public EmbOS documentation does not specify how it handles calls to
// its timer create API if the values lie beyond the specified interval of
// 1 ≤ Period ≤ 0x7FFFFFFF. Since there's not return value to assess API
// call success, we clamp the delay to the supported interval.
// Note that since the EmbOS timer is a millisecond tick timer, an additional
// delay of 1ms is added to the requested delay to avoid clipping/zeroing
// during the time factor conversion.
// TODO(b/237819962): Investigate the possibility of a spare hardware timer
// available on SLSI that we can eventually switch to.
constexpr uint64_t kMinDelayMs = 1;
constexpr uint64_t kMaxDelayMs = INT32_MAX;
uint64_t delayMs = Milliseconds(delay).getMilliseconds();
delayMs = std::min(std::max(delayMs + 1, kMinDelayMs), kMaxDelayMs);
OS_StopTimerEx(&mTimer);
OS_SetTimerPeriodEx(&mTimer, static_cast<OS_TIME>(delayMs));
mCallback = callback;
mData = data;
OS_RetriggerTimerEx(&mTimer);
return true;
}
// The return value for this function is not guaranteed to be correct - please
// see the note in @ref SystemTimerBase.
bool SystemTimer::cancel() {
bool success = false;
if (isActive()) {
OS_StopTimerEx(&mTimer);
success = true;
}
return success;
}
bool SystemTimer::isActive() {
return (OS_GetTimerStatusEx(&mTimer) != 0);
}
} // namespace chre