mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2024-09-20 09:49:15 +03:00
b91c49364d
This makes it more symmetrical with adopt_own() (which is used to create a NonnullOwnPtr from the result of a naked new.)
90 lines
2.3 KiB
C++
90 lines
2.3 KiB
C++
/*
|
|
* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#include <Kernel/Arch/x86/CPU.h>
|
|
#include <Kernel/CMOS.h>
|
|
#include <Kernel/IO.h>
|
|
#include <Kernel/Time/RTC.h>
|
|
#include <Kernel/Time/TimeManagement.h>
|
|
|
|
namespace Kernel {
|
|
#define IRQ_TIMER 8
|
|
#define MAX_FREQUENCY 8000
|
|
|
|
NonnullRefPtr<RealTimeClock> RealTimeClock::create(Function<void(const RegisterState&)> callback)
|
|
{
|
|
return adopt_ref(*new RealTimeClock(move(callback)));
|
|
}
|
|
RealTimeClock::RealTimeClock(Function<void(const RegisterState&)> callback)
|
|
: HardwareTimer(IRQ_TIMER, move(callback))
|
|
{
|
|
InterruptDisabler disabler;
|
|
NonMaskableInterruptDisabler nmi_disabler;
|
|
enable_irq();
|
|
CMOS::write(0x8B, CMOS::read(0xB) | 0x40);
|
|
reset_to_default_ticks_per_second();
|
|
}
|
|
void RealTimeClock::handle_irq(const RegisterState& regs)
|
|
{
|
|
HardwareTimer::handle_irq(regs);
|
|
CMOS::read(0x8C);
|
|
}
|
|
|
|
size_t RealTimeClock::ticks_per_second() const
|
|
{
|
|
return m_frequency;
|
|
}
|
|
|
|
void RealTimeClock::reset_to_default_ticks_per_second()
|
|
{
|
|
InterruptDisabler disabler;
|
|
bool success = try_to_set_frequency(1024);
|
|
VERIFY(success);
|
|
}
|
|
|
|
// FIXME: This is a quick & dirty log base 2 with a parameter. Please provide something better in the future.
|
|
static int quick_log2(size_t number)
|
|
{
|
|
int count = 0;
|
|
while (number >>= 1)
|
|
count++;
|
|
return count;
|
|
}
|
|
|
|
bool RealTimeClock::try_to_set_frequency(size_t frequency)
|
|
{
|
|
InterruptDisabler disabler;
|
|
if (!is_capable_of_frequency(frequency))
|
|
return false;
|
|
disable_irq();
|
|
u8 previous_rate = CMOS::read(0x8A);
|
|
u8 rate = quick_log2(32768 / frequency) + 1;
|
|
dbgln("RTC: Set rate to {}", rate);
|
|
CMOS::write(0x8A, (previous_rate & 0xF0) | rate);
|
|
m_frequency = frequency;
|
|
dbgln("RTC: Set frequency to {} Hz", frequency);
|
|
enable_irq();
|
|
return true;
|
|
}
|
|
bool RealTimeClock::is_capable_of_frequency(size_t frequency) const
|
|
{
|
|
VERIFY(frequency != 0);
|
|
if (frequency > MAX_FREQUENCY)
|
|
return false;
|
|
if (32768 % frequency)
|
|
return false;
|
|
|
|
u16 divider = 32768 / frequency;
|
|
return (divider <= 16384 && divider >= 4); // Frequency can be in range of 2 Hz to 8 KHz
|
|
}
|
|
size_t RealTimeClock::calculate_nearest_possible_frequency(size_t frequency) const
|
|
{
|
|
VERIFY(frequency != 0);
|
|
return frequency;
|
|
}
|
|
|
|
}
|