arbdma.c

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/*
 * PROJECT:     ReactOS Kernel
 * LICENSE:     MIT (https://spdx.org/licenses/MIT)
 * PURPOSE:     PnP manager Root DMA Arbiter
 * COPYRIGHT:   Copyright 2025-2026 Justin Miller <justin.miller@reactos.org>
 */
 
/* INCLUDES *****************************************************************/
 
#include <ntoskrnl.h>
#define NDEBUG
#include <debug.h>
 
/* GLOBALS *******************************************************************/
 
extern ARBITER_INSTANCE IopRootDmaArbiter;
 
/* FUNCTIONS *****************************************************************/
 
NTSTATUS
NTAPI
IopArbDmaUnpackRequirements(
    _In_ PIO_RESOURCE_DESCRIPTOR IoDescriptor,
    _Out_ PUINT64 OutMinimumAddress,
    _Out_ PUINT64 OutMaximumAddress,
    _Out_ PUINT64 OutLength,
    _Out_ PUINT64 OutAlignment)
{
    PAGED_CODE();
 
    *OutMinimumAddress = IoDescriptor->u.Dma.MinimumChannel;
    *OutMaximumAddress = IoDescriptor->u.Dma.MaximumChannel;
    *OutLength    = 1;
    *OutAlignment = 1;
 
    return STATUS_SUCCESS;
}
 
NTSTATUS
NTAPI
IopArbDmaPackResource(
    _In_ PIO_RESOURCE_DESCRIPTOR IoDescriptor,
    _In_ UINT64 Start,
    _Out_ PCM_PARTIAL_RESOURCE_DESCRIPTOR CmDescriptor)
{
    PAGED_CODE();
 
    CmDescriptor->Type = CmResourceTypeDma;
    CmDescriptor->ShareDisposition = IoDescriptor->ShareDisposition;
    CmDescriptor->Flags = IoDescriptor->Flags;
 
    /*
     * TODO: this is only version gated temporarily,
     * we need this for USB3 eventually, I marked it for now.
     */
#if (NTDDI_VERSION >= NTDDI_WIN8)
    if (IoDescriptor->Flags & CM_RESOURCE_DMA_V3)
    {
        CmDescriptor->u.DmaV3.Channel       = IoDescriptor->u.DmaV3.Channel;
        CmDescriptor->u.DmaV3.RequestLine   = IoDescriptor->u.DmaV3.RequestLine;
        CmDescriptor->u.DmaV3.TransferWidth = (UCHAR)IoDescriptor->u.DmaV3.TransferWidth;
        return STATUS_SUCCESS;
    }
#endif
 
    CmDescriptor->u.Dma.Channel = (ULONG)Start;
    CmDescriptor->u.Dma.Port    = 0;
 
    return STATUS_SUCCESS;
}
 
NTSTATUS
NTAPI
IopArbDmaUnpackResource(
    _In_ PCM_PARTIAL_RESOURCE_DESCRIPTOR CmDescriptor,
    _Out_ PUINT64 Start,
    _Out_ PUINT64 OutLength)
{
    PAGED_CODE();
 
    *Start = CmDescriptor->u.Dma.Channel;
    *OutLength = 1;
 
    return STATUS_SUCCESS;
}
 
INT32
NTAPI
IopArbDmaScoreRequirement(
    _In_ PIO_RESOURCE_DESCRIPTOR IoDescriptor)
{
    PAGED_CODE();
    return (INT32)(IoDescriptor->u.Dma.MaximumChannel - IoDescriptor->u.Dma.MinimumChannel);
}
 
NTSTATUS
NTAPI
IopArbDmaInitialize(VOID)
{
    NTSTATUS Status = STATUS_UNSUCCESSFUL;
 
    PAGED_CODE();
    IopRootDmaArbiter.Name = L"RootDma";
    IopRootDmaArbiter.UnpackRequirement = IopArbDmaUnpackRequirements;
    IopRootDmaArbiter.PackResource = IopArbDmaPackResource;
    IopRootDmaArbiter.UnpackResource = IopArbDmaUnpackResource;
    IopRootDmaArbiter.ScoreRequirement = IopArbDmaScoreRequirement;
 
    Status = ArbiterLibInitializeInstance(&IopRootDmaArbiter,
                                          NULL,
                                          CmResourceTypeDma,
                                          IopRootDmaArbiter.Name,
                                          L"Root",
                                          NULL);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("IopArbDmaInitialize: Failed with %X", Status);
    }
 
    return Status;
}