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0a2d520b15
Since CLINT interrupts are wired directly into the hart, instead of going through an interrupt controller (the PLIC), trying to handle them through the normal numbered-interrupt mechanism will just complicate it for no reason. Instead we now handle them directly in the trap handler.
85 lines
2.3 KiB
C++
85 lines
2.3 KiB
C++
/*
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* Copyright (c) 2023, Sönke Holz <sholz8530@gmail.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Format.h>
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#include <Kernel/Arch/riscv64/CPU.h>
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#include <Kernel/Arch/riscv64/SBI.h>
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#include <Kernel/Arch/riscv64/Timer.h>
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namespace Kernel::RISCV64 {
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static Timer* s_the;
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Timer::Timer()
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{
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m_frequency = DeviceTree::get().resolve_property("/cpus/timebase-frequency"sv).value().as<u32>();
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m_interrupt_interval = m_frequency / OPTIMAL_TICKS_PER_SECOND_RATE;
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set_compare(current_ticks() + m_interrupt_interval);
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RISCV64::CSR::set_bits(RISCV64::CSR::Address::SIE, 1 << (to_underlying(CSR::SCAUSE::SupervisorTimerInterrupt) & ~CSR::SCAUSE_INTERRUPT_MASK));
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}
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NonnullLockRefPtr<Timer> Timer::initialize()
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{
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VERIFY(!s_the);
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auto timer = adopt_lock_ref(*new Timer);
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s_the = timer.ptr();
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return timer;
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}
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Timer& Timer::the()
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{
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VERIFY(s_the);
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return *s_the;
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}
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u64 Timer::current_ticks()
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{
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return RISCV64::CSR::read(RISCV64::CSR::Address::TIME);
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}
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void Timer::handle_interrupt(RegisterState const& regs)
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{
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if (m_callback)
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m_callback(regs);
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set_compare(current_ticks() + m_interrupt_interval);
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}
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u64 Timer::update_time(u64& seconds_since_boot, u32& ticks_this_second, bool query_only)
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{
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// Should only be called by the time keeper interrupt handler!
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u64 current_value = current_ticks();
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u64 delta_ticks = m_main_counter_drift;
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if (current_value >= m_main_counter_last_read) {
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delta_ticks += current_value - m_main_counter_last_read;
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} else {
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// the counter wrapped around
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delta_ticks += (NumericLimits<u64>::max() - m_main_counter_last_read + 1) + current_value;
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}
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u64 ticks_since_last_second = (u64)ticks_this_second + delta_ticks;
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auto frequency = ticks_per_second();
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seconds_since_boot += ticks_since_last_second / frequency;
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ticks_this_second = ticks_since_last_second % frequency;
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if (!query_only) {
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m_main_counter_drift = 0;
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m_main_counter_last_read = current_value;
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}
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// Return the time passed (in ns) since last time update_time was called
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return (delta_ticks * 1000000000ull) / frequency;
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}
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void Timer::set_compare(u64 compare)
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{
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if (SBI::Timer::set_timer(compare).is_error())
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MUST(SBI::Legacy::set_timer(compare));
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}
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}
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