We need to write an application that plays an audio using the sound card, we want the application to use McBSP, DMA & 
PCM device for this purpose (we wish not to pass audio data through IO-Audio path) and hence I have the following 
queries,

1. Do we need to create the PCM device for transferring the data ?
	If yes, how can we do that without using 'ado_pcm_create' function ?
2. We want to configure the DMA in chain linking mode how can we do that ?
3. How can we register DMA interrupt handler  without using 'ado_attach_interrupt' function ?
4. Is 'rsrcdbmgr_attach' function call is necessary else how can we handle multiple requests to the same channel ?