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DMA_OPERATIONS structure

The DMA_OPERATIONS structure provides a table of pointers to functions that control the operation of a DMA controller.

Syntax


typedef struct _DMA_OPERATIONS {
  ULONG                               Size;
  PPUT_DMA_ADAPTER                    PutDmaAdapter;
  PALLOCATE_COMMON_BUFFER             AllocateCommonBuffer;
  PFREE_COMMON_BUFFER                 FreeCommonBuffer;
  PALLOCATE_ADAPTER_CHANNEL           AllocateAdapterChannel;
  PFLUSH_ADAPTER_BUFFERS              FlushAdapterBuffers;
  PFREE_ADAPTER_CHANNEL               FreeAdapterChannel;
  PFREE_MAP_REGISTERS                 FreeMapRegisters;
  PMAP_TRANSFER                       MapTransfer;
  PGET_DMA_ALIGNMENT                  GetDmaAlignment;
  PREAD_DMA_COUNTER                   ReadDmaCounter;
  PGET_SCATTER_GATHER_LIST            GetScatterGatherList;
  PPUT_SCATTER_GATHER_LIST            PutScatterGatherList;
  PCALCULATE_SCATTER_GATHER_LIST_SIZE CalculateScatterGatherList;
  PBUILD_SCATTER_GATHER_LIST          BuildScatterGatherList;
  PBUILD_MDL_FROM_SCATTER_GATHER_LIST BuildMdlFromScatterGatherList;
  PGET_DMA_ADAPTER_INFO               GetDmaAdapterInfo;
  PGET_DMA_TRANSFER_INFO              GetDmaTransferInfo;
  PINITIALIZE_DMA_TRANSFER_CONTEXT    InitializeDmaTransferContext;
  PALLOCATE_COMMON_BUFFER_EX          AllocateCommonBufferEx;
  PALLOCATE_ADAPTER_CHANNEL_EX        AllocateAdapterChannelEx;
  PCONFIGURE_ADAPTER_CHANNEL          ConfigureAdapterChannel;
  PCANCEL_ADAPTER_CHANNEL             CancelAdapterChannel;
  PMAP_TRANSFER_EX                    MapTransferEx;
  PGET_SCATTER_GATHER_LIST_EX         GetScatterGatherListEx;
  PBUILD_SCATTER_GATHER_LIST_EX       BuildScatterGatherListEx;
  PFLUSH_ADAPTER_BUFFERS_EX           FlushAdapterBuffersEx;
  PFREE_ADAPTER_OBJECT                FreeAdapterObject;
  PCANCEL_MAPPED_TRANSFER             CancelMappedTransfer;
} DMA_OPERATIONS, *PDMA_OPERATIONS;

Members

Size

The size, in bytes, of this DMA_OPERATIONS structure.

PutDmaAdapter

A pointer to a system-defined routine to free a DMA_ADAPTER structure. For more information, see PutDmaAdapter.

AllocateCommonBuffer

A pointer to a system-defined routine to allocate a physically contiguous DMA buffer. For more information, see AllocateCommonBuffer.

FreeCommonBuffer

A pointer to a system-defined routine to free a physically contiguous DMA buffer previously allocated by AllocateCommonBuffer. For more information, see FreeCommonBuffer.

AllocateAdapterChannel

A pointer to a system-defined routine to allocate a channel for DMA operations. For more information, see AllocateAdapterChannel.

FlushAdapterBuffers

A pointer to a system-defined routine to flush data from the system or bus-master adapter's internal cache after a DMA operation. For more information, see FlushAdapterBuffers.

FreeAdapterChannel

A pointer to a system-defined routine to free a channel previously allocated for DMA operations by AllocateAdapterChannel. For more information, see FreeAdapterChannel.

FreeMapRegisters

A pointer to a system-defined routine to free map registers allocated for DMA operations. For more information, see FreeMapRegisters.

MapTransfer

A pointer to a system-defined routine to begin a DMA operation. For more information, see MapTransfer.

GetDmaAlignment

A pointer to a system-defined routine to obtain the DMA alignment requirements of the controller. For more information, see GetDmaAlignment.

ReadDmaCounter

A pointer to a system-defined routine to obtain the current transfer count for a DMA operation. For more information, see ReadDmaCounter.

GetScatterGatherList

A pointer to a system-defined routine that allocates map registers and creates a scatter/gather list for DMA. For more information, see GetScatterGatherList.

PutScatterGatherList

A pointer to a system-defined routine that frees map registers and a scatter/gather list after a DMA operation is complete. For more information, see PutScatterGatherList.

CalculateScatterGatherList

A pointer to a system-defined routine that determines the buffer size needed to hold the scatter/gather list that describes an I/O data buffer. This member is available only in versions 2 and later of DMA_OPERATIONS. For more information, see CalculateScatterGatherList.

BuildScatterGatherList

A pointer to a system-defined routine that allocates map registers and creates a scatter/gather list for DMA in a driver-supplied buffer. This member is available only in versions 2 and later of DMA_OPERATIONS. For more information, see BuildScatterGatherList.

BuildMdlFromScatterGatherList

A pointer to a system-defined routine that builds an MDL corresponding to a scatter/gather list. This member is available only in versions 2 and later of DMA_OPERATIONS. For more information, see BuildMdlFromScatterGatherList.

GetDmaAdapterInfo

A pointer to a system-defined routine that describes the capabilities of a bus-master DMA device or a system DMA controller. GetDmaAdapterInfo is available only in version 3 of DMA_OPERATIONS. For more information, see GetDmaAdapterInfo.

GetDmaTransferInfo

A pointer to a system-defined routine that describes the allocation requirements for a scatter/gather list. This routine replaces CalculateScatterGatherList. GetDmaTransferInfo is available only in version 3 of DMA_OPERATIONS. For more information, see GetDmaTransferInfo.

InitializeDmaTransferContext

A pointer to a system-defined routine that initializes an opaque DMA transfer context. The operating system stores the internal status of a DMA transfer in this context. InitializeDmaTransferContext is available only in version 3 of DMA_OPERATIONS. For more information, see InitializeDmaTransferContext.

AllocateCommonBufferEx

A pointer to a system-defined routine that allocates memory for a common buffer and maps this memory so that it can accessed both by the processor and by a DMA device. AllocateCommonBufferEx is available only in version 3 of DMA_OPERATIONS. For more information, see AllocateCommonBufferEx.

AllocateAdapterChannelEx

A pointer to a system-defined routine that allocates the resources required for a DMA transfer and then calls the driver-supplied AdapterControl routine to initiate the DMA transfer. AllocateAdapterChannelEx is available only in version 3 of DMA_OPERATIONS. For more information, see AllocateAdapterChannelEx.

ConfigureAdapterChannel

A pointer to a system-defined routine enables a custom function that is implemented by the DMA controller. ConfigureAdapterChannel is available only in version 3 of DMA_OPERATIONS. For more information, see ConfigureAdapterChannel.

CancelAdapterChannel

A pointer to a system-defined routine that tries to cancel a pending request to allocate a DMA channel. CancelAdapterChannel is available only in version 3 of DMA_OPERATIONS. For more information, see CancelAdapterChannel.

MapTransferEx

A pointer to a system-defined routine that sets up map registers to map the physical addresses in a scatter/gather list to the logical addresses that are required to do a DMA transfer. MapTransferEx is available only in version 3 of DMA_OPERATIONS. For more information, see MapTransferEx.

GetScatterGatherListEx

A pointer to a system-defined routine that allocates resources required for a DMA transfer, builds a scatter/gather list, and then calls the driver-supplied AdapterListControl routine to initiate the DMA transfer. GetScatterGatherListEx is available only in version 3 of DMA_OPERATIONS. For more information, see GetScatterGatherListEx. This routine is a wrapper of AllocateAdapterChannelEx and MapTransferEx.

BuildScatterGatherListEx

A pointer to a system-defined routine that builds a scatter/gather list in a caller-allocated buffer, and then calls the driver-supplied AdapterListControl routine to initiate the DMA transfer. BuildScatterGatherListEx is available only in version 3 of DMA_OPERATIONS. For more information, see BuildScatterGatherListEx.

FlushAdapterBuffersEx

A pointer to a system-defined routine that flushes any data that remains in the system DMA controller's internal cache or in a bus-master adapter's internal cache at the end of a DMA transfer. For a device that uses a system DMA controller, this routine cancels the current DMA transfer on the controller if the transfer is not complete. FlushAdapterBuffersEx is available only in version 3 of DMA_OPERATIONS. For more information, see FlushAdapterBuffersEx.

FreeAdapterObject

A pointer to a system-defined routine that releases the specified adapter object after a driver has completed all DMA operations. FreeAdapterObject is available only in version 3 of DMA_OPERATIONS. For more information, see FreeAdapterObject.

CancelMappedTransfer

A pointer to a system-defined routine that cancels a mapped transfer. CancelMappedTransfer is available only in version 3 of DMA_OPERATIONS. For more information, see CancelMappedTransfer.

Remarks

All members of this structure, with the exception of Size, are pointers to functions that drivers use to perform DMA operations for their devices. Drivers obtain these pointers by calling the IoGetDmaAdapter routine. The version of the DMA_OPERATIONS structure that this routine returns depends on the Version member of the DEVICE_DESCRIPTION structure that is passed to IoGetDmaAdapter as an input parameter. If Version is DEVICE_DESCRIPTION_VERSION or DEVICE_DESCRIPTION_VERSION1, version 1 of this structure is returned. If Version is DEVICE_DESCRIPTION_VERSION2, version 2 of this structure is returned. Version 2 of DMA_OPERATIONS is available starting with Windows XP. If Version is DEVICE_DESCRIPTION_VERSION3, version 3 of this structure is returned. Version 3 of DMA_OPERATIONS is available starting with Windows 8.

Requirements

Version

Supported starting with Windows 2000.

Header

Wdm.h (include Wdm.h, Ntddk.h, or Ntifs.h)

See also

AllocateAdapterChannel
AllocateAdapterChannelEx
AllocateCommonBuffer
AllocateCommonBufferEx
BuildMdlFromScatterGatherList
BuildScatterGatherList
BuildScatterGatherListEx
CalculateScatterGatherList
CancelAdapterChannel
CancelMappedTransfer
ConfigureAdapterChannel
DEVICE_DESCRIPTION
FlushAdapterBuffers
FlushAdapterBuffersEx
FreeAdapterChannel
FreeAdapterObject
FreeCommonBuffer
FreeMapRegisters
GetDmaAdapterInfo
GetDmaAlignment
GetDmaTransferInfo
GetScatterGatherList
GetScatterGatherListEx
InitializeDmaTransferContext
IoGetDmaAdapter
MapTransfer
MapTransferEx
PutDmaAdapter
PutScatterGatherList
ReadDmaCounter

 

 

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