72 lines
1.7 KiB
C++
72 lines
1.7 KiB
C++
/*
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* \brief Time source using Nova timed semaphore down
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* \author Alexander Boettcher
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* \author Martin Stein
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* \date 2014-06-24
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*/
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/*
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* Copyright (C) 2014-2015 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#ifndef _TIME_SOURCE_H_
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#define _TIME_SOURCE_H_
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/* Genode includes */
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#include <trace/timestamp.h>
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/* local includes */
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#include <threaded_time_source.h>
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namespace Timer { class Time_source; }
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class Timer::Time_source : public Threaded_time_source
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{
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private:
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Genode::addr_t _sem = ~0UL;
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unsigned long _timeout_us = 0;
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Genode::Trace::Timestamp _tsc_start = Genode::Trace::timestamp();
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unsigned long _tsc_khz;
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/* 1 / ((us / (1000 * 1000)) * (tsc_khz * 1000)) */
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enum { TSC_FACTOR = 1000ULL };
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inline Microseconds _tsc_to_us(unsigned long long tsc,
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bool sub_tsc_start = true) const
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{
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if (sub_tsc_start) {
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return Microseconds((tsc - _tsc_start) /
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(_tsc_khz / TSC_FACTOR));
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}
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return Microseconds((tsc) / (_tsc_khz / TSC_FACTOR));
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}
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/**************************
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** Threaded_time_source **
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**************************/
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void _wait_for_irq();
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public:
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Time_source(Genode::Entrypoint &ep);
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/*************************
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** Genode::Time_source **
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*************************/
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Microseconds max_timeout() const override { return _tsc_to_us(~0UL); }
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void schedule_timeout(Microseconds duration, Timeout_handler &handler) override;
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Microseconds curr_time() const override {
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return _tsc_to_us(Genode::Trace::timestamp()); }
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};
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#endif /* _TIME_SOURCE_H_ */
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