WDC_DMATransactionContigInit()

DWORD DLLCALLCONV WDC_DMATransactionContigInit	(	_In_ WDC_DEVICE_HANDLE	hDev,
		_Outptr_ PVOID *	ppBuf,
		_In_ DWORD	dwOptions,
		_In_ DWORD	dwDMABufSize,
		_Outptr_ WD_DMA **	ppDma,
		_In_ WDC_INTERRUPT_PARAMS *	pInterruptParams,
		_In_ DWORD	dwAlignment
	)

Initializes the transaction, allocates a contiguous DMA buffer, locks it in physical memory, and returns mappings of the allocated buffer to physical address space and to user-mode and kernel virtual address spaces.

Parameters

[in]	hDev	Handle to a WDC device, returned by WDC_xxxDeviceOpen()
[out]	ppBuf	Pointer to a pointer to be filled by the function with the user-mode mapped address of the allocated DMA buffer.
[in]	dwOptions	A bit mask of any of the following flags (defined in an enumeration in windrvr.h): DMA_FROM_DEVICE: Synchronize the DMA buffer for transfers from the device to memory. DMA_TO_DEVICE: Synchronize the DMA buffer for transfers from memory to the device. DMA_TO_FROM_DEVICE: Synchronize the DMA buffer for transfers in both directions i.e., from the device to memory and from memory to the device (<=> DMA_FROM_DEVICE | DMA_TO_DEVICE). DMA_ALLOW_CACHE: Allow caching of the memory. DMA_ALLOW_64BIT_ADDRESS: Allow allocation of 64-bit DMA addresses.
[in]	dwDMABufSize	The size (in bytes) of the DMA buffer.
[out]	ppDma	Pointer to a pointer to a DMA buffer information structur, which is allocated by the function. The pointer to this structure (*ppDma) should be passed to WDC_DMATransactionUninit() when the DMA buffer is no longer needed.
[in]	pInterruptParams	WDC_DMATransactionContigInit() invokes WDC_IntEnable() with the relevant parameters from the structure (WDC_INTERRUPT_PARAMS). No action will be taken if this parameter is NULL.
[in]	dwAlignment	This value specifies the alignment requirement for the contiguous buffer.

Returns

Returns WD_STATUS_SUCCESS (0) on success, or an appropriate error code otherwise

For more detailed usage of the WDC_DMA Transactions functions, please refer to 11.3. Performing Direct Memory Access (DMA) transactions