EVT_WDF_PROGRAM_DMA - NtDoc
Native API online documentation, based on the System Informer
(formerly Process Hacker) phnt
headers
// wdfdmatransaction.h
EVT_WDF_PROGRAM_DMA EvtWdfProgramDma;
BOOLEAN EvtWdfProgramDma(
[in] WDFDMATRANSACTION Transaction,
[in] WDFDEVICE Device,
[in] WDFCONTEXT Context,
[in] WDF_DMA_DIRECTION Direction,
[in] PSCATTER_GATHER_LIST SgList
)
{...}
View the official Windows Driver Kit DDI referenceNo description available.
[Applies to KMDF only]
A framework-based driver's EvtProgramDma event callback function programs a specified device to perform a DMA transfer operation.
Transaction [in]A handle to the DMA transaction object that represents the current DMA transaction.
Device [in]A handle to a framework device object.
Context [in]The context pointer that the driver specified in a previous call to WdfDmaTransactionExecute.
Direction [in]A WDF_DMA_DIRECTION-typed value that specifies the direction of the DMA transfer operation.
SgList [in]A pointer to a SCATTER_GATHER_LIST structure.
The EvtProgramDma callback function must return TRUE if it successfully starts the DMA transfer operation. Otherwise, this callback function must return FALSE. However, the framework currently ignores the return value.
Drivers register an EvtProgramDma event callback function by calling WdfDmaTransactionInitializeUsingRequest or WdfDmaTransactionInitialize.
The framework calls a driver's EvtProgramDma event callback function when a DMA transfer is available. The callback function must program the hardware to start the transfer.
The driver must not manipulate the data buffers associated with the transaction until after WdfDmaTransactionDmaCompletedXxx has returned TRUE.
For single packet transfers, the scatter/gather list that the SgList parameter points to contains a single element.
For more information about this callback function, see Programming DMA Hardware.
WdfDmaTransactionInitializeUsingRequest