legacypcirqarb.c

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/*
 * PROJECT:     ReactOS HAL
 * LICENSE:     MIT (https://spdx.org/licenses/MIT)
 * PURPOSE:     Legacy HAL IRQ Arbiter
 * COPYRIGHT:   Copyright 2026 Justin Miller <justin.miller@reactos.org>
 */
 
#include <hal.h>
#include <arbiter.h>
 
static ARBITER_INSTANCE LegacyPCArbiter;
 
static
CODE_SEG("PAGE")
NTSTATUS
NTAPI
HalpLegacyPCArbUnpackRequirement(
    _In_ PIO_RESOURCE_DESCRIPTOR IoDescriptor,
    _Out_ PUINT64 OutMinimumAddress,
    _Out_ PUINT64 OutMaximumAddress,
    _Out_ PUINT64 OutLength,
    _Out_ PUINT64 OutAlignment)
{
    PAGED_CODE();
 
    ASSERT(IoDescriptor->Type == CmResourceTypeInterrupt);
 
    *OutMinimumAddress = (UINT64)IoDescriptor->u.Interrupt.MinimumVector;
    *OutMaximumAddress = (UINT64)IoDescriptor->u.Interrupt.MaximumVector;
    *OutLength = 1;
    *OutAlignment = 1;
    return STATUS_SUCCESS;
}
 
static
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NTSTATUS
NTAPI
HalpLegacyPCArbPackResource(
    _In_ PIO_RESOURCE_DESCRIPTOR IoDescriptor,
    _In_ UINT64 Start,
    _Out_ PCM_PARTIAL_RESOURCE_DESCRIPTOR CmDescriptor)
{
    PAGED_CODE();
 
    ASSERT(IoDescriptor->Type == CmResourceTypeInterrupt);
 
    /* Our vectors live in a ULONG, and the PIR table never goes past 15 anyway. */
    if (Start > MAXULONG)
        return STATUS_INVALID_PARAMETER;
 
    CmDescriptor->Type = CmResourceTypeInterrupt;
    CmDescriptor->ShareDisposition = IoDescriptor->ShareDisposition;
    CmDescriptor->Flags = IoDescriptor->Flags;
    CmDescriptor->u.Interrupt.Level = (ULONG)Start;
    CmDescriptor->u.Interrupt.Vector = (ULONG)Start;
    CmDescriptor->u.Interrupt.Affinity = (KAFFINITY)-1;
    return STATUS_SUCCESS;
}
 
static
CODE_SEG("PAGE")
NTSTATUS
NTAPI
HalpLegacyPCArbUnpackResource(
    _In_ PCM_PARTIAL_RESOURCE_DESCRIPTOR CmDescriptor,
    _Out_ PUINT64 Start,
    _Out_ PUINT64 OutLength)
{
    PAGED_CODE();
 
    ASSERT(CmDescriptor->Type == CmResourceTypeInterrupt);
 
    *Start = CmDescriptor->u.Interrupt.Vector;
    *OutLength = 1;
    return STATUS_SUCCESS;
}
 
static
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INT32
NTAPI
HalpLegacyPCArbScoreRequirement(
    _In_ PIO_RESOURCE_DESCRIPTOR IoDescriptor)
{
    INT32 ScoreReg;
 
    PAGED_CODE();
 
    ASSERT(IoDescriptor->Type == CmResourceTypeInterrupt);
 
    ScoreReg = (INT32)(IoDescriptor->u.Interrupt.MaximumVector - IoDescriptor->u.Interrupt.MinimumVector + 1);
 
    return (ScoreReg < 0) ? MAXLONG : ScoreReg;
}
 
static
VOID
NTAPI
HalpLegacyPCArbReference(PVOID Context)
{
    NOTHING;
}
 
static
VOID
NTAPI
HalpLegacyPCArbDereference(PVOID Context)
{
    NOTHING;
}
 
CODE_SEG("PAGE")
NTSTATUS
NTAPI
HalpLegacyPCCreateArbiter(
    _In_ PDEVICE_OBJECT BusFdo)
{
    NTSTATUS Status;
 
    PAGED_CODE();
 
    LegacyPCArbiter.UnpackRequirement = HalpLegacyPCArbUnpackRequirement;
    LegacyPCArbiter.PackResource = HalpLegacyPCArbPackResource;
    LegacyPCArbiter.UnpackResource = HalpLegacyPCArbUnpackResource;
    LegacyPCArbiter.ScoreRequirement = HalpLegacyPCArbScoreRequirement;
 
    /*
     * TODO: Later we'll override more when we implement PIR.
     * The most important piece for now here is the clamp.
     * This will let us boot for now, preserving orignal reactos behavior.
     * (Plug and Pray)
     */
 
    Status = ArbiterLibInitializeInstance(&LegacyPCArbiter,
                                          BusFdo,
                                          CmResourceTypeInterrupt,
                                          L"HalIRQ",
                                          L"Root",
                                          NULL);
    if (!NT_SUCCESS(Status))
    {
        return Status;
    }
 
    /* Lock to the 0-15 the PIR table only understands. */
    RtlAddRange(LegacyPCArbiter.Allocation, 16, ARBITER_MAXIMUM_ADDRESS, 0,
                RTL_RANGE_LIST_ADD_IF_CONFLICT, NULL, NULL);
    RtlAddRange(LegacyPCArbiter.Allocation, PIC_CASCADE_IRQ, PIC_CASCADE_IRQ,
                0, RTL_RANGE_LIST_ADD_IF_CONFLICT, NULL, NULL);
 
    return Status;
}
 
CODE_SEG("PAGE")
NTSTATUS
NTAPI
HalpLegacyPCQueryArbInterface(
    _Out_writes_bytes_(Size) PVOID Interface,
    _In_ ULONG Size,
    _Out_ PULONG Length)
{
    PARBITER_INTERFACE ArbiterInterface = Interface;
 
    PAGED_CODE();
 
    *Length = sizeof(*ArbiterInterface);
    if (Size < sizeof(*ArbiterInterface))
        return STATUS_BUFFER_TOO_SMALL;
 
    ArbiterInterface->Size = sizeof(*ArbiterInterface);
    ArbiterInterface->Version = 1;
    ArbiterInterface->Context = &LegacyPCArbiter;
    ArbiterInterface->ArbiterHandler = ArbiterLibHandler;
    ArbiterInterface->Flags = 0;
 
    ArbiterInterface->InterfaceDereference = HalpLegacyPCArbDereference;
    ArbiterInterface->InterfaceReference = HalpLegacyPCArbReference;
 
    return STATUS_SUCCESS;
}