DMA_ADAPTER structure (wdm.h)

The DMA_ADAPTER structure describes a system-defined interface to a DMA controller for a given device. A driver calls IoGetDmaAdapter to obtain this structure.

Syntax

typedef struct _DMA_ADAPTER {
  USHORT          Version;
  USHORT          Size;
  PDMA_OPERATIONS DmaOperations;
} *PADAPTER_OBJECT, DMA_ADAPTER, *PDMA_ADAPTER;

Members

Version

Specifies the version of this structure. Version 3 of the DMA_ADAPTER structure is available starting with Windows 8. For versions 1 and 2 of this structure, this member is set to the value 1. For more information, see the following Remarks section.

Size

Specifies the size, in bytes, of this structure.

DmaOperations

Pointer to a DMA_OPERATIONS structure that contains pointers to DMA adapter functions. The version of the DMA_OPERATIONS structure that this member points to is determined by the version of the DMA_ADAPTER structure. Thus, for version 1 of the DMA_ADAPTER structure, DmaOperations points to version 1 of the DMA_OPERATIONS structure, and so on. For more information about structure versions, see the following Remarks section.

Remarks

Drivers for devices that use DMA to transfer data use this structure to obtain the addresses of functions that enable use of a DMA controller. Usually, drivers obtain this structure by calling the IoGetDmaAdapter routine. Drivers can also obtain this structure by querying for the BUS_INTERFACE_STANDARD interface.

When the IoGetDmaAdapter routine returns a pointer to version 1 or version 2 of the DMA_ADAPTER structure, this routine always sets the Version member of this structure to 1. Thus, the caller cannot use the Version member to distinguish between versions 1 and 2 of the DMA_ADAPTER structure. For more information about how to determine the version of a DMA_ADAPTER structure that is returned by this routine, see IoGetDmaAdapter.

Requirements

Requirement	Value
Header	wdm.h (include Wdm.h, Ntddk.h, Ntifs.h)

See also

BUS_INTERFACE_STANDARD

DMA_OPERATIONS

IoGetDmaAdapter