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https://github.com/RGBCube/serenity
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6d2c298b66
As there is no need for a Prekernel on aarch64, the Prekernel code was moved into Kernel itself. The functionality remains the same. SERENITY_KERNEL_AND_INITRD in run.sh specifies a kernel and an inital ramdisk to be used by the emulator. This is needed because aarch64 does not need a Prekernel and the other ones do.
88 lines
2.2 KiB
C++
88 lines
2.2 KiB
C++
/*
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* Copyright (c) 2021, Nico Weber <thakis@chromium.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <Kernel/Arch/aarch64/MMIO.h>
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#include <Kernel/Arch/aarch64/Mailbox.h>
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#include <Kernel/Arch/aarch64/Timer.h>
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#include <Kernel/Arch/aarch64/Utils.h>
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namespace Prekernel {
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// "12.1 System Timer Registers" / "10.2 System Timer Registers"
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struct TimerRegisters {
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u32 control_and_status;
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u32 counter_low;
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u32 counter_high;
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u32 compare[4];
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};
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// Bits of the `control_and_status` register.
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// See "CS register" in Broadcom doc for details.
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enum FlagBits {
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SystemTimerMatch0 = 1 << 0,
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SystemTimerMatch1 = 1 << 1,
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SystemTimerMatch2 = 1 << 2,
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SystemTimerMatch3 = 1 << 3,
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};
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Timer::Timer()
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: m_registers(MMIO::the().peripheral<TimerRegisters>(0x3000))
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{
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}
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Timer& Timer::the()
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{
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static Timer instance;
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return instance;
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}
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u64 Timer::microseconds_since_boot()
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{
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u32 high = m_registers->counter_high;
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u32 low = m_registers->counter_low;
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if (high != m_registers->counter_high) {
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high = m_registers->counter_high;
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low = m_registers->counter_low;
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}
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return (static_cast<u64>(high) << 32) | low;
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}
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class SetClockRateMboxMessage : Prekernel::Mailbox::Message {
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public:
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u32 clock_id;
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u32 rate_hz;
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u32 skip_setting_turbo;
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SetClockRateMboxMessage()
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: Prekernel::Mailbox::Message(0x0003'8002, 12)
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{
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clock_id = 0;
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rate_hz = 0;
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skip_setting_turbo = 0;
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}
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};
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u32 Timer::set_clock_rate(ClockID clock_id, u32 rate_hz, bool skip_setting_turbo)
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{
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struct __attribute__((aligned(16))) {
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Prekernel::Mailbox::MessageHeader header;
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SetClockRateMboxMessage set_clock_rate;
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Prekernel::Mailbox::MessageTail tail;
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} message_queue;
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message_queue.set_clock_rate.clock_id = static_cast<u32>(clock_id);
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message_queue.set_clock_rate.rate_hz = rate_hz;
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message_queue.set_clock_rate.skip_setting_turbo = skip_setting_turbo ? 1 : 0;
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if (!Prekernel::Mailbox::the().send_queue(&message_queue, sizeof(message_queue))) {
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warnln("Timer::set_clock_rate() failed!");
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return 0;
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}
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return message_queue.set_clock_rate.rate_hz;
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}
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}
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