156 lines
4.2 KiB
C++
156 lines
4.2 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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* System clock functions.
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*/
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#ifdef HAVE_ANDROID_OS
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#include <linux/ioctl.h>
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#include <linux/rtc.h>
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#include <utils/Atomic.h>
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#include <linux/android_alarm.h>
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#endif
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#include <sys/time.h>
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#include <limits.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <string.h>
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#include <utils/SystemClock.h>
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#include <utils/Timers.h>
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#define LOG_TAG "SystemClock"
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#include <utils/Log.h>
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namespace android {
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/*
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* native public static long uptimeMillis();
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*/
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int64_t uptimeMillis()
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{
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int64_t when = systemTime(SYSTEM_TIME_MONOTONIC);
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return (int64_t) nanoseconds_to_milliseconds(when);
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}
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/*
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* native public static long elapsedRealtime();
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*/
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int64_t elapsedRealtime()
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{
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return nanoseconds_to_milliseconds(elapsedRealtimeNano());
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}
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#define METHOD_CLOCK_GETTIME 0
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#define METHOD_IOCTL 1
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#define METHOD_SYSTEMTIME 2
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static const char *gettime_method_names[] = {
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"clock_gettime",
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"ioctl",
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"systemTime",
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};
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static inline void checkTimeStamps(int64_t timestamp,
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int64_t volatile *prevTimestampPtr,
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int volatile *prevMethodPtr,
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int curMethod)
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{
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/*
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* Disable the check for SDK since the prebuilt toolchain doesn't contain
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* gettid, and int64_t is different on the ARM platform
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* (ie long vs long long).
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*/
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#ifdef ARCH_ARM
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int64_t prevTimestamp = *prevTimestampPtr;
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int prevMethod = *prevMethodPtr;
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if (timestamp < prevTimestamp) {
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ALOGW("time going backwards: prev %lld(%s) vs now %lld(%s), tid=%d",
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prevTimestamp, gettime_method_names[prevMethod],
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timestamp, gettime_method_names[curMethod],
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gettid());
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}
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// NOTE - not atomic and may generate spurious warnings if the 64-bit
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// write is interrupted or not observed as a whole.
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*prevTimestampPtr = timestamp;
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*prevMethodPtr = curMethod;
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#endif
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}
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/*
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* native public static long elapsedRealtimeNano();
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*/
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int64_t elapsedRealtimeNano()
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{
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#ifdef HAVE_ANDROID_OS
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struct timespec ts;
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int result;
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int64_t timestamp;
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static volatile int64_t prevTimestamp;
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static volatile int prevMethod;
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#if 0
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/*
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* b/7100774
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* clock_gettime appears to have clock skews and can sometimes return
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* backwards values. Disable its use until we find out what's wrong.
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*/
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result = clock_gettime(CLOCK_BOOTTIME, &ts);
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if (result == 0) {
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timestamp = seconds_to_nanoseconds(ts.tv_sec) + ts.tv_nsec;
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checkTimeStamps(timestamp, &prevTimestamp, &prevMethod,
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METHOD_CLOCK_GETTIME);
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return timestamp;
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}
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#endif
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// CLOCK_BOOTTIME doesn't exist, fallback to /dev/alarm
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static int s_fd = -1;
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if (s_fd == -1) {
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int fd = open("/dev/alarm", O_RDONLY);
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if (android_atomic_cmpxchg(-1, fd, &s_fd)) {
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close(fd);
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}
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}
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result = ioctl(s_fd,
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ANDROID_ALARM_GET_TIME(ANDROID_ALARM_ELAPSED_REALTIME), &ts);
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if (result == 0) {
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timestamp = seconds_to_nanoseconds(ts.tv_sec) + ts.tv_nsec;
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checkTimeStamps(timestamp, &prevTimestamp, &prevMethod, METHOD_IOCTL);
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return timestamp;
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}
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// XXX: there was an error, probably because the driver didn't
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// exist ... this should return
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// a real error, like an exception!
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timestamp = systemTime(SYSTEM_TIME_MONOTONIC);
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checkTimeStamps(timestamp, &prevTimestamp, &prevMethod,
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METHOD_SYSTEMTIME);
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return timestamp;
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#else
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return systemTime(SYSTEM_TIME_MONOTONIC);
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#endif
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}
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}; // namespace android
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