WDC_DMABufGet()

DWORD DLLCALLCONV WDC_DMABufGet	(	_In_ DWORD	hDma,
		_Outptr_ WD_DMA **	ppDma
	)

Retrieves a contiguous DMA buffer which was allocated by another process.

Parameters

[in]	hDma	DMA buffer handle.
[out]	ppDma	Pointer to a pointer to a DMA buffer information structure, which is associated with hDma.

Returns

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

For more detailed usage of the WDC_DMA functions, please refer to 11.2. Performing Direct Memory Access (DMA)

static void ipc_msg_event_cb(WDS_IPC_MSG_RX *pIpcRxMsg, void *pData)
{
    printf("\n\nReceived an IPC message:\n"
        "msgID [0x%lx], msgData [0x%llx] from process [0x%lx]\n",
        pIpcRxMsg->dwMsgID, pIpcRxMsg->qwMsgData, pIpcRxMsg->dwSenderUID);
 
    /* In this example, the hDma was sent by the other process and saved it
        in pIpcRxMsg->qwMsgData. The current process gets the buffer by the IPC
        message event callback */
 
    switch (pIpcRxMsg->dwMsgID)
    {
    case IPC_MSG_CONTIG_DMA_BUFFER_READY:
        {
            DWORD dwStatus;
            WD_DMA *pDma = NULL;
 
            printf("\nThis is a DMA buffer, getting it...\n");
 
            dwStatus = WDC_DMABufGet((DWORD)pIpcRxMsg->qwMsgData, &pDma);
            if (WD_STATUS_SUCCESS != dwStatus)
            {
                printf("ipc_msg_event_cb: Failed getting DMA buffer. "
                    "Error [0x%lx - %s]\n", dwStatus, Stat2Str(dwStatus));
                return;
            }
 
            printf("Got a DMA buffer. UserAddr [%p], "
                "pPhysicalAddr [0x%"PRI64"x], size [%ld(0x%lx)]\n",
                pDma->pUserAddr, pDma->Page[0].pPhysicalAddr,
                pDma->Page[0].dwBytes, pDma->Page[0].dwBytes);
 
            /* For sample purpose we immediately release the buffer */
            WDC_DMABufUnlock(pDma);
        }
        break;
 
    default:
        printf("Unknown IPC type. msgID [0x%lx], msgData [0x%llx] from "
            "process [0x%lx]\n\n", pIpcRxMsg->dwMsgID, pIpcRxMsg->qwMsgData,
            pIpcRxMsg->dwSenderUID);
    }
}