66 lines
1.6 KiB
C++
66 lines
1.6 KiB
C++
/*
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* \brief Timer implementation specific to BCM2835 System Timer
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* \author Norman Feske
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* \author Stefan Kalkowski
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* \author Martin Stein
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* \date 2016-01-07
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*/
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/*
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* Copyright (C) 2016-2017 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 Affero General Public License version 3.
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*/
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/* core includes */
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#include <board.h>
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#include <platform.h>
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#include <kernel/timer.h>
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using namespace Genode;
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using namespace Kernel;
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using Device = Board::Timer;
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Board::Timer::Timer(unsigned)
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: Mmio(Platform::mmio_to_virt(Board::SYSTEM_TIMER_MMIO_BASE)) { }
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void Timer::_start_one_shot(time_t const ticks)
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{
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_device.write<Device::Cs::M1>(1);
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_device.read<Device::Cs>();
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_device.write<Device::Cmp>(_device.read<Device::Clo>()
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+ (ticks < 2 ? 2 : ticks));
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}
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enum { TICS_PER_US = Board::SYSTEM_TIMER_CLOCK / 1000 / 1000 };
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time_t Timer::ticks_to_us(time_t const ticks) const {
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return ticks / TICS_PER_US; }
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time_t Timer::us_to_ticks(time_t const us) const {
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return us * TICS_PER_US; }
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time_t Timer::_max_value() const {
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return 0xffffffff; }
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time_t Timer::_duration() const
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{
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Device::Clo::access_t const clo = _device.read<Device::Clo>();
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Device::Cmp::access_t const cmp = _device.read<Device::Cmp>();
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Device::Cs::access_t const irq = _device.read<Device::Cs::M1>();
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uint32_t d = (irq) ? (uint32_t)_last_timeout_duration + (clo - cmp)
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: clo - (cmp - _last_timeout_duration);
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return d;
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}
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unsigned Timer::interrupt_id() const { return Board::SYSTEM_TIMER_IRQ; }
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