1 /*
2 * Copyright (C) 2022 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 #include <algorithm>
17 #include <cinttypes>
18
19 #include "chre/platform/fatal_error.h"
20 #include "chre/platform/log.h"
21 #include "chre/platform/system_timer.h"
22 #include "chre/util/time.h"
23
24 namespace chre {
25
invokeCallback(void * instance)26 void SystemTimerBase::invokeCallback(void *instance) {
27 auto *timer = static_cast<SystemTimer *>(instance);
28 timer->mCallback(timer->mData);
29 }
30
SystemTimer()31 SystemTimer::SystemTimer() {}
32
~SystemTimer()33 SystemTimer::~SystemTimer() {
34 // cancel an existing timer if any, and delete the timer instance.
35 cancel();
36 OS_DeleteTimerEx(&mTimer);
37 }
38
init()39 bool SystemTimer::init() {
40 constexpr uint32_t kSomeInitialPeriod = 100;
41 OS_CreateTimerEx(&mTimer, SystemTimerBase::invokeCallback, kSomeInitialPeriod,
42 this /*context*/);
43 return true;
44 }
45
set(SystemTimerCallback * callback,void * data,Nanoseconds delay)46 bool SystemTimer::set(SystemTimerCallback *callback, void *data,
47 Nanoseconds delay) {
48 // The public EmbOS documentation does not specify how it handles calls to
49 // its timer create API if the values lie beyond the specified interval of
50 // 1 ≤ Period ≤ 0x7FFFFFFF. Since there's not return value to assess API
51 // call success, we clamp the delay to the supported interval.
52 // Note that since the EmbOS timer is a millisecond tick timer, an additional
53 // delay of 1ms is added to the requested delay to avoid clipping/zeroing
54 // during the time factor conversion.
55 // TODO(b/237819962): Investigate the possibility of a spare hardware timer
56 // available on SLSI that we can eventually switch to.
57 constexpr uint64_t kMinDelayMs = 1;
58 constexpr uint64_t kMaxDelayMs = INT32_MAX;
59 uint64_t delayMs = Milliseconds(delay).getMilliseconds();
60 delayMs = std::min(std::max(delayMs + 1, kMinDelayMs), kMaxDelayMs);
61
62 OS_StopTimerEx(&mTimer);
63 OS_SetTimerPeriodEx(&mTimer, static_cast<OS_TIME>(delayMs));
64
65 mCallback = callback;
66 mData = data;
67
68 OS_RetriggerTimerEx(&mTimer);
69 return true;
70 }
71
72 // The return value for this function is not guaranteed to be correct - please
73 // see the note in @ref SystemTimerBase.
cancel()74 bool SystemTimer::cancel() {
75 bool success = false;
76 if (isActive()) {
77 OS_StopTimerEx(&mTimer);
78 success = true;
79 }
80 return success;
81 }
82
isActive()83 bool SystemTimer::isActive() {
84 return (OS_GetTimerStatusEx(&mTimer) != 0);
85 }
86
87 } // namespace chre
88