38 lines
1.3 KiB
C++
38 lines
1.3 KiB
C++
/*
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* CpuIdle.hpp
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* ACPI-guided CPU idle-state selection
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* Copyright (c) 2026 Daniel Hammer
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*/
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#pragma once
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#include <cstdint>
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#include <ACPI/ACPI.hpp>
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namespace Hal {
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namespace CpuIdle {
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// Initialize ACPI idle-state policy from the AML namespace and FADT.
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void Initialize(ACPI::CommonSDTHeader* xsdt);
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// Enter an idle state chosen for the predicted idle duration.
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// Falls back to MWAIT/HLT when ACPI data is unavailable.
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void Wait(uint32_t predictedIdleMs, bool hasMwait,
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volatile uint64_t* monitorAddr = nullptr);
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// Same as Wait(), but called with interrupts disabled and returns with
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// interrupts disabled. Used by tickless idle paths that need atomic
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// STI+HLT/MWAIT semantics.
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void WaitWithInterruptsDisabled(uint32_t predictedIdleMs, bool hasMwait,
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volatile uint64_t* monitorAddr = nullptr);
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// Shallow atomic idle for latency-sensitive interactive bursts.
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void WaitShallowWithInterruptsDisabled(bool hasMwait,
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volatile uint64_t* monitorAddr = nullptr);
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// The MWAIT hint APs use for deep idle (0 = plain C1). Exposed for
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// SYS_POWERINFO diagnostics.
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uint8_t GetApIdleHint();
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};
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};
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