dmaengine: edma: Serve cyclic (audio) channels with high priority queue

Move the DMA channel used in cyclic mode (audio) to the highest priority
event queue which helps to reduce audio problems.
When the channel is terminated, move it back to the default queue.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/edma.c

@@ -256,8 +256,13 @@ static int edma_terminate_all(struct edma_chan *echan)
 	 * echan->edesc is NULL and exit.)
 	 */
 	if (echan->edesc) {
+		int cyclic = echan->edesc->cyclic;
 		echan->edesc = NULL;
 		edma_stop(echan->ch_num);
+		/* Move the cyclic channel back to default queue */
+		if (cyclic)
+			edma_assign_channel_eventq(echan->ch_num,
+						   EVENTQ_DEFAULT);
 	}
 
 	vchan_get_all_descriptors(&echan->vchan, &head);
@@ -724,6 +729,9 @@ static struct dma_async_tx_descriptor *edma_prep_dma_cyclic(
 			edesc->pset[i].param.opt |= TCINTEN;
 	}
 
+	/* Place the cyclic channel to highest priority queue */
+	edma_assign_channel_eventq(echan->ch_num, EVENTQ_0);
+
 	return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
 }