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/*
* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Arch/x86_64/IO.h>
#include <Kernel/Arch/x86_64/Time/PIT.h>
#include <Kernel/Interrupts/GenericInterruptHandler.h>
#include <Kernel/Interrupts/InterruptDisabler.h>
#include <Kernel/Sections.h>
#include <Kernel/Tasks/Scheduler.h>
#include <Kernel/Tasks/Thread.h>
#include <Kernel/Time/TimeManagement.h>
#define IRQ_TIMER 0
namespace Kernel {
UNMAP_AFTER_INIT NonnullLockRefPtr<PIT> PIT::initialize(Function<void(RegisterState const&)> callback)
{
return adopt_lock_ref(*new PIT(move(callback)));
}
[[maybe_unused]] 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(RegisterState const&)> callback)
: HardwareTimer(IRQ_TIMER, move(callback))
, m_periodic(true)
{
IO::out8(PIT_CTL, TIMER0_SELECT | WRITE_WORD | MODE_SQUARE_WAVE);
dmesgln("PIT: {} Hz, square wave ({:#08x})", OPTIMAL_TICKS_PER_SECOND_RATE, 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()
{
IO::out8(PIT_CTL, TIMER0_CTL | WRITE_WORD | MODE_SQUARE_WAVE);
m_periodic = true;
}
void PIT::set_non_periodic()
{
IO::out8(PIT_CTL, TIMER0_CTL | WRITE_WORD | MODE_ONESHOT);
m_periodic = false;
}
void PIT::reset_to_default_ticks_per_second()
{
InterruptDisabler disabler;
bool success = try_to_set_frequency(OPTIMAL_TICKS_PER_SECOND_RATE);
VERIFY(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
{
VERIFY(frequency != 0);
return frequency <= BASE_FREQUENCY;
}
size_t PIT::calculate_nearest_possible_frequency(size_t frequency) const
{
VERIFY(frequency != 0);
return frequency;
}
}
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