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/*
* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <Kernel/Assertions.h>
#include <Kernel/Time/HPETComparator.h>
#include <Kernel/Time/TimeManagement.h>
//#define HPET_COMPARATOR_DEBUG
namespace Kernel {
NonnullRefPtr<HPETComparator> HPETComparator::create(u8 number, u8 irq, bool periodic_capable)
{
return adopt(*new HPETComparator(number, irq, periodic_capable));
}
HPETComparator::HPETComparator(u8 number, u8 irq, bool periodic_capable)
: HardwareTimer(irq)
, m_periodic(false)
, m_periodic_capable(periodic_capable)
, m_comparator_number(number)
{
}
void HPETComparator::set_periodic()
{
ASSERT(m_periodic_capable);
HPET::the().enable_periodic_interrupt(*this);
m_periodic = true;
}
void HPETComparator::set_non_periodic()
{
ASSERT(m_periodic_capable);
HPET::the().disable_periodic_interrupt(*this);
m_periodic = false;
}
void HPETComparator::handle_irq(const RegisterState& regs)
{
HardwareTimer::handle_irq(regs);
if (!is_periodic())
set_new_countdown();
}
void HPETComparator::set_new_countdown()
{
ASSERT_INTERRUPTS_DISABLED();
ASSERT(m_frequency <= HPET::the().frequency());
HPET::the().set_non_periodic_comparator_value(*this, HPET::the().frequency() / m_frequency);
}
size_t HPETComparator::ticks_per_second() const
{
return m_frequency;
}
void HPETComparator::reset_to_default_ticks_per_second()
{
ASSERT(is_capable_of_frequency(OPTIMAL_TICKS_PER_SECOND_RATE));
m_frequency = OPTIMAL_TICKS_PER_SECOND_RATE;
if (!is_periodic())
set_new_countdown();
else
try_to_set_frequency(m_frequency);
}
bool HPETComparator::try_to_set_frequency(size_t frequency)
{
InterruptDisabler disabler;
if (!is_capable_of_frequency(frequency))
return false;
disable_irq();
auto hpet_frequency = HPET::the().frequency();
ASSERT(frequency <= hpet_frequency);
#ifdef HPET_COMPARATOR_DEBUG
dbg() << "HPET Comparator: Max frequency - " << hpet_frequency << " Hz, want to set " << frequency << " Hz";
#endif
if (is_periodic())
HPET::the().set_periodic_comparator_value(*this, hpet_frequency / frequency);
else {
HPET::the().set_non_periodic_comparator_value(*this, hpet_frequency / frequency);
HPET::the().enable(*this);
}
m_frequency = frequency;
enable_irq();
return true;
}
bool HPETComparator::is_capable_of_frequency(size_t frequency) const
{
if (frequency > HPET::the().frequency())
return false;
if ((HPET::the().frequency() % frequency) != 0)
return false;
return true;
}
size_t HPETComparator::calculate_nearest_possible_frequency(size_t frequency) const
{
if (frequency >= HPET::the().frequency())
return HPET::the().frequency();
// FIXME: Use better math here
return (frequency + (HPET::the().frequency() % frequency));
}
}
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