PFLUSH_ADAPTER_BUFFERS - NtDoc
Native API online documentation, based on the System Informer
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headers
// wdm.h
PFLUSH_ADAPTER_BUFFERS PflushAdapterBuffers;
BOOLEAN PflushAdapterBuffers(
[in] PDMA_ADAPTER DmaAdapter,
[in] PMDL Mdl,
[in] PVOID MapRegisterBase,
[in] PVOID CurrentVa,
[in] ULONG Length,
[in] BOOLEAN WriteToDevice
)
{...}
View the official Windows Driver Kit DDI referenceNo description available.
The FlushAdapterBuffers routine flushes any data remaining in the system DMA controller's internal cache or in a bus-master adapter's internal cache at the end of a DMA transfer operation.
DmaAdapter [in]Pointer to the DMA_ADAPTER structure returned by IoGetDmaAdapter that represents the bus-master adapter or DMA controller.
Mdl [in]Pointer to the MDL that describes the buffer previously passed in the driver's call to MapTransfer.
MapRegisterBase [in]Specifies the map registers allocated for the DMA operation. The system passes this value to the driver's AdapterControl routine.
CurrentVa [in]Pointer to the current virtual address in the buffer, described by the Mdl, where the I/O operation occurred. This value must be the same as the initial CurrentVa value passed to MapTransfer.
Length [in]Specifies the length, in bytes, of the buffer.
WriteToDevice [in]Specifies the direction of the DMA transfer operation: TRUE for a transfer from a buffer in system memory to the driver's device.
FlushAdapterBuffers returns TRUE if any data remaining in the DMA controller's or bus-master adapter's internal cache has been successfully flushed into system memory or out to the device.
FlushAdapterBuffers is not a system routine that can be called directly by name. This routine is callable only by pointer from the address returned in a DMA_OPERATIONS structure. Drivers obtain the address of this routine by calling IoGetDmaAdapter.
To ensure that a DMA transfer is complete, every driver that performs DMA operations must call FlushAdapterBuffers before completing the IRP that requested the DMA transfer and before freeing the map registers.
A driver can get the initial CurrentVa for the start of a packet-based DMA transfer by calling MmGetMdlVirtualAddress. However, the value returned is an index into the Mdl, rather than a valid virtual address. If the driver must split a large transfer request into more than one DMA operation, it must update CurrentVa and Length for each DMA operation.