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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/Arch/i386/CPU.h>
#include <Kernel/IO.h>
#include <Kernel/Interrupts/PIC.h>
#include <Kernel/Scheduler.h>
#include <Kernel/Thread.h>
#include <Kernel/Time/PIT.h>
#include <Kernel/Time/TimeManagement.h>
#define IRQ_TIMER 0
namespace Kernel {
NonnullRefPtr<PIT> PIT::initialize(Function<void(const RegisterState&)> callback)
{
return adopt(*new PIT(move(callback)));
}
inline static void reset_countdown(u16 timer_reload)
{
IO::out8(PIT_CTL, TIMER0_SELECT | WRITE_WORD | MODE_COUNTDOWN);
IO::out8(TIMER0_CTL, LSB(timer_reload));
IO::out8(TIMER0_CTL, MSB(timer_reload));
}
PIT::PIT(Function<void(const RegisterState&)> callback)
: HardwareTimer(IRQ_TIMER, move(callback))
, m_periodic(true)
{
IO::out8(PIT_CTL, TIMER0_SELECT | WRITE_WORD | MODE_SQUARE_WAVE);
klog() << "PIT: " << OPTIMAL_TICKS_PER_SECOND_RATE << " Hz, square wave (" << String::format("%x", BASE_FREQUENCY / OPTIMAL_TICKS_PER_SECOND_RATE) << ")";
reset_to_default_ticks_per_second();
enable_irq();
}
size_t PIT::ticks_per_second() const
{
return m_frequency;
}
void PIT::set_periodic()
{
// FIXME: Implement it...
ASSERT_NOT_REACHED();
}
void PIT::set_non_periodic()
{
// FIXME: Implement it...
ASSERT_NOT_REACHED();
}
void PIT::reset_to_default_ticks_per_second()
{
InterruptDisabler disabler;
bool success = try_to_set_frequency(OPTIMAL_TICKS_PER_SECOND_RATE);
ASSERT(success);
}
bool PIT::try_to_set_frequency(size_t frequency)
{
InterruptDisabler disabler;
if (!is_capable_of_frequency(frequency))
return false;
disable_irq();
size_t reload_value = BASE_FREQUENCY / frequency;
IO::out8(TIMER0_CTL, LSB(reload_value));
IO::out8(TIMER0_CTL, MSB(reload_value));
m_frequency = frequency;
enable_irq();
return true;
}
bool PIT::is_capable_of_frequency(size_t frequency) const
{
ASSERT(frequency != 0);
return frequency <= BASE_FREQUENCY;
}
size_t PIT::calculate_nearest_possible_frequency(size_t frequency) const
{
ASSERT(frequency != 0);
return frequency;
}
}
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