mirror of
https://github.com/RGBCube/serenity
synced 2025-10-28 11:02:36 +00:00
89 lines
2.2 KiB
C++
89 lines
2.2 KiB
C++
/*
|
|
* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#include <Kernel/Arch/x86/InterruptDisabler.h>
|
|
#include <Kernel/IO.h>
|
|
#include <Kernel/Interrupts/GenericInterruptHandler.h>
|
|
#include <Kernel/Scheduler.h>
|
|
#include <Kernel/Sections.h>
|
|
#include <Kernel/Thread.h>
|
|
#include <Kernel/Time/PIT.h>
|
|
#include <Kernel/Time/TimeManagement.h>
|
|
|
|
#define IRQ_TIMER 0
|
|
namespace Kernel {
|
|
|
|
UNMAP_AFTER_INIT NonnullRefPtr<PIT> PIT::initialize(Function<void(const RegisterState&)> callback)
|
|
{
|
|
return adopt_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(const RegisterState&)> 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()
|
|
{
|
|
// FIXME: Implement it...
|
|
VERIFY_NOT_REACHED();
|
|
}
|
|
void PIT::set_non_periodic()
|
|
{
|
|
// FIXME: Implement it...
|
|
VERIFY_NOT_REACHED();
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
}
|