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/* |
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* Copyright (C) 2005-2008 by Pieter Palmers |
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* Copytight (C) 2012 by Jonathan Woithe |
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* |
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* This file is part of FFADO |
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* FFADO = Free Firewire (pro-)audio drivers for linux |
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* |
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* FFADO is based upon FreeBoB. |
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* |
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* This program is free software: you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation, either version 2 of the License, or |
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* (at your option) version 3 of the License. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program. If not, see <http://www.gnu.org/licenses/>. |
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* |
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*/ |
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#include "config.h" |
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#include "SystemTimeSource.h" |
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#include "Time.h" |
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// needed for clock_nanosleep |
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#ifndef _GNU_SOURCE |
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#define _GNU_SOURCE |
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#endif |
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#include <time.h> |
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#include <stdlib.h> |
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DECLARE_GLOBAL_DEBUG_MODULE; |
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namespace Util { |
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static clockid_t clock_id = CLOCK_REALTIME; |
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bool |
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SystemTimeSource::setSource(clockid_t id) |
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{ |
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struct timespec tp; |
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// Determine at runtime whether the kernel has support for the |
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// requested clock source. |
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if (clock_gettime(id, &tp) == 0) { |
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clock_id = id; |
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return true; |
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} |
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return false; |
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} |
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clockid_t |
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SystemTimeSource::getSource(void) |
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{ |
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return clock_id; |
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} |
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int |
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SystemTimeSource::clockGettime(struct timespec *tp) |
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{ |
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return clock_gettime(clock_id, tp); |
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} |
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void |
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SystemTimeSource::SleepUsecRelative(ffado_microsecs_t usecs) |
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{ |
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//usleep(usecs); |
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struct timespec ts; |
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ts.tv_sec = usecs / (1000000LL); |
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ts.tv_nsec = (usecs % (1000000LL)) * 1000LL; |
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// clock_nanosleep() is not implemented for CLOCK_MONOTONIC_RAW. |
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// If the clock source is CLOCK_MONOTONIC_RAW, use CLOCK_MONOTONIC |
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// as an approximation for the purposes of sleep timing. |
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clockid_t clk = (clock_id==CLOCK_MONOTONIC_RAW)?CLOCK_MONOTONIC:clock_id; |
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clock_nanosleep(clk, 0, &ts, NULL); |
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} |
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void |
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SystemTimeSource::SleepUsecAbsolute(ffado_microsecs_t wake_at_usec) |
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{ |
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// If the system time is based on CLOCK_MONOTONIC_RAW we can't use |
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// TIMER_ABSTIME because wake_at_usec will be in terms of |
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// CLOCK_MONOTONIC_RAW while clock_nanosleep() can at best use only |
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// CLOCK_MONOTONIC. There is, AFAIK, no guarantee that the two are even |
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// remotely related. For now, resolve this problem by unconditionally |
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// disabling the use of TIMER_ABSTIME here, regardless of the setting of |
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// USE_ABSOLUTE_NANOSLEEP. Jonathan Woithe, 25 June 2012. |
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#if USE_ABSOLUTE_NANOSLEEP && 0 |
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// CLOCK_MONOTONIC_RAW isn't supported by clock_nanosleep() |
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clockid_t clk = (clock_id==CLOCK_MONOTONIC_RAW)?CLOCK_MONOTONIC:clock_id; |
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struct timespec ts; |
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ts.tv_sec = wake_at_usec / (1000000LL); |
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ts.tv_nsec = (wake_at_usec % (1000000LL)) * 1000LL; |
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debugOutputExtreme(DEBUG_LEVEL_VERBOSE, |
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"clock_nanosleep until %"PRId64" sec, %"PRId64" nanosec\n", |
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(int64_t)ts.tv_sec, (int64_t)ts.tv_nsec); |
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int err = clock_nanosleep(clk, TIMER_ABSTIME, &ts, NULL); |
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if(err) { |
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// maybe signal occurred, but we're going to ignore that |
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} |
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debugOutputExtreme(DEBUG_LEVEL_VERBOSE, |
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"back with err=%d\n", |
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err); |
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#else |
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// only sleep if needed |
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ffado_microsecs_t now = getCurrentTime(); |
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if(wake_at_usec >= now) { |
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ffado_microsecs_t to_sleep = wake_at_usec - now; |
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SleepUsecRelative(to_sleep); |
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} |
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#endif |
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} |
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ffado_microsecs_t |
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SystemTimeSource::SleepUsecRandom(ffado_microsecs_t max_usec) |
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{ |
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long int rnd = random(); |
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long long int tmp = (rnd*max_usec); |
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tmp /= RAND_MAX; |
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ffado_microsecs_t usec = tmp; |
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SleepUsecRelative(usec); |
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return usec; |
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} |
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ffado_microsecs_t |
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SystemTimeSource::getCurrentTime() |
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{ |
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return getCurrentTimeAsUsecs(); |
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} |
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ffado_microsecs_t |
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SystemTimeSource::getCurrentTimeAsUsecs() |
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{ |
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struct timespec ts; |
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clock_gettime(clock_id, &ts); |
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return (ffado_microsecs_t)(ts.tv_sec * 1000000LL + ts.tv_nsec / 1000LL); |
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} |
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} // end of namespace Util |
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