0d934fc991
Alot of code is shared between i386/i686/x86 and x86_64 and a lot probably will be used for compatability modes. So we start by moving the headers into one Directory. We will probalby be able to move some cpp files aswell.
109 lines
3.5 KiB
C++
109 lines
3.5 KiB
C++
/*
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* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <Kernel/Arch/x86/CPU.h>
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#include <Kernel/CMOS.h>
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#include <Kernel/IO.h>
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#include <Kernel/Time/RTC.h>
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#include <Kernel/Time/TimeManagement.h>
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namespace Kernel {
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#define IRQ_TIMER 8
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#define MAX_FREQUENCY 8000
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NonnullRefPtr<RealTimeClock> RealTimeClock::create(Function<void(const RegisterState&)> callback)
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{
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return adopt(*new RealTimeClock(move(callback)));
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}
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RealTimeClock::RealTimeClock(Function<void(const RegisterState&)> callback)
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: HardwareTimer(IRQ_TIMER, move(callback))
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{
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InterruptDisabler disabler;
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NonMaskableInterruptDisabler nmi_disabler;
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enable_irq();
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CMOS::write(0x8B, CMOS::read(0xB) | 0x40);
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reset_to_default_ticks_per_second();
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}
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void RealTimeClock::handle_irq(const RegisterState& regs)
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{
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HardwareTimer::handle_irq(regs);
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CMOS::read(0x8C);
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}
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size_t RealTimeClock::ticks_per_second() const
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{
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return m_frequency;
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}
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void RealTimeClock::reset_to_default_ticks_per_second()
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{
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InterruptDisabler disabler;
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bool success = try_to_set_frequency(1024);
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VERIFY(success);
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}
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// FIXME: This is a quick & dirty log base 2 with a parameter. Please provide something better in the future.
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static int quick_log2(size_t number)
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{
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int count = 0;
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while (number >>= 1)
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count++;
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return count;
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}
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bool RealTimeClock::try_to_set_frequency(size_t frequency)
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{
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InterruptDisabler disabler;
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if (!is_capable_of_frequency(frequency))
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return false;
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disable_irq();
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u8 previous_rate = CMOS::read(0x8A);
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u8 rate = quick_log2(32768 / frequency) + 1;
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dbgln("RTC: Set rate to {}", rate);
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CMOS::write(0x8A, (previous_rate & 0xF0) | rate);
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m_frequency = frequency;
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dbgln("RTC: Set frequency to {} Hz", frequency);
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enable_irq();
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return true;
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}
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bool RealTimeClock::is_capable_of_frequency(size_t frequency) const
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{
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VERIFY(frequency != 0);
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if (frequency > MAX_FREQUENCY)
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return false;
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if (32768 % frequency)
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return false;
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u16 divider = 32768 / frequency;
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return (divider <= 16384 && divider >= 4); // Frequency can be in range of 2 Hz to 8 KHz
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}
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size_t RealTimeClock::calculate_nearest_possible_frequency(size_t frequency) const
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{
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VERIFY(frequency != 0);
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return frequency;
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}
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}
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