This book does not cover Direct Memory Access (DMA) in detail. However, NT 3.51 and NT 4 driver writers will find that they must access the DMA system routines in a new way. All the same routines are there, you just have to call IoGetDmaAdapter first. This returns a pointer to a DMA_ADAPTER object. The DmaOperations field in there contains pointers to all the familiar routines. Call the DmaOperations PutDmaAdapter callback when you have finished with the DMA_ADAPTER object.
Table C.1 shows the corresponding old and new routines. Just to reiterate, there is no kernel routine directly called PutDmaAdapter. This routine is only available through the DMA_ADAPTER structure, e.g.,
(*DmaAdapter->DmaOperations->PutDmaAdapter)(DmaAdapter);
Table C.1 Old and new DMA routines
| Old | New | New DmaOperations routine | Description |
|---|---|---|---|
HalGetAdapter | IoGetDmaAdapter | ||
PutDmaAdapter | Release DmaAdapter | ||
HalAllocateCommonBuffer | AllocateCommonBuffer | ||
HalFreeCommonBuffer | FreeCommonBuffer | ||
IoAllocateAdapterChannel | AllocateAdapterChannel | ||
IoFlushAdapterBuffers | FlushAdapterBuffers | ||
IoFreeAdapterChannel | FreeAdapterChannel | ||
IoFreeMapRegisters | FreeMapRegisters | ||
IoMapTransfer | MapTransfer | ||
HalGetDmaAlignmentRequirement | GetDmaAlignment | Get alignment requirements for DMA buffers | |
HalReadDmaCounter | ReadDmaCounter | Get number of bytes remaining to be transferred | |
GetScatterGatherList | |||
PutScatterGatherList |