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b035267afa
If a hardware timer doesn't have a callback registered, it's now simply represented by a null m_callback.
127 lines
4.1 KiB
C++
127 lines
4.1 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/Assertions.h>
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#include <Kernel/Time/HPETComparator.h>
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#include <Kernel/Time/TimeManagement.h>
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//#define HPET_COMPARATOR_DEBUG
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namespace Kernel {
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NonnullRefPtr<HPETComparator> HPETComparator::create(u8 number, u8 irq, bool periodic_capable)
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{
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return adopt(*new HPETComparator(number, irq, periodic_capable));
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}
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HPETComparator::HPETComparator(u8 number, u8 irq, bool periodic_capable)
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: HardwareTimer(irq)
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, m_periodic(false)
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, m_periodic_capable(periodic_capable)
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, m_comparator_number(number)
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{
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}
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void HPETComparator::set_periodic()
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{
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ASSERT(m_periodic_capable);
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HPET::the().enable_periodic_interrupt(*this);
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m_periodic = true;
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}
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void HPETComparator::set_non_periodic()
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{
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ASSERT(m_periodic_capable);
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HPET::the().disable_periodic_interrupt(*this);
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m_periodic = false;
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}
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void HPETComparator::handle_irq(const RegisterState& regs)
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{
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HardwareTimer::handle_irq(regs);
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if (!is_periodic())
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set_new_countdown();
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}
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void HPETComparator::set_new_countdown()
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{
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ASSERT_INTERRUPTS_DISABLED();
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ASSERT(m_frequency <= HPET::the().frequency());
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HPET::the().set_non_periodic_comparator_value(*this, HPET::the().frequency() / m_frequency);
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}
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size_t HPETComparator::ticks_per_second() const
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{
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return m_frequency;
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}
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void HPETComparator::reset_to_default_ticks_per_second()
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{
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ASSERT(is_capable_of_frequency(OPTIMAL_TICKS_PER_SECOND_RATE));
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m_frequency = OPTIMAL_TICKS_PER_SECOND_RATE;
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if (!is_periodic())
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set_new_countdown();
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else
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try_to_set_frequency(m_frequency);
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}
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bool HPETComparator::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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auto hpet_frequency = HPET::the().frequency();
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ASSERT(frequency <= hpet_frequency);
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#ifdef HPET_COMPARATOR_DEBUG
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dbg() << "HPET Comparator: Max frequency - " << hpet_frequency << " Hz, want to set " << frequency << " Hz";
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#endif
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if (is_periodic())
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HPET::the().set_periodic_comparator_value(*this, hpet_frequency / frequency);
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else {
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HPET::the().set_non_periodic_comparator_value(*this, hpet_frequency / frequency);
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HPET::the().enable(*this);
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}
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m_frequency = frequency;
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enable_irq();
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return true;
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}
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bool HPETComparator::is_capable_of_frequency(size_t frequency) const
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{
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if (frequency > HPET::the().frequency())
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return false;
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if ((HPET::the().frequency() % frequency) != 0)
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return false;
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return true;
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}
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size_t HPETComparator::calculate_nearest_possible_frequency(size_t frequency) const
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{
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if (frequency >= HPET::the().frequency())
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return HPET::the().frequency();
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// FIXME: Use better math here
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return (frequency + (HPET::the().frequency() % frequency));
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}
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}
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