dma: dma-axi-dmac: fix HW scatter-gather not looking at the queue

For HW scatter gather transfers we still need to look for the queue. The
HW is capable of queueing 3 concurrent transfers and if we try more than
that we'll get the submit queue full and should return. Otherwise, if we
go ahead and program the new transfer, we end up discarding it.

Fixes: e97dc74 ("dmaengine: axi-dmac: Add support for scatter-gather transfers")
Signed-off-by: Nuno Sá <[email protected]>
(cherry picked from commit 0dac3bc)

Author: nunojsa

drivers/dma/dma-axi-dmac.c

@@ -236,11 +236,9 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
 	unsigned int flags = 0;
 	unsigned int val;
 
-	if (!chan->hw_sg) {
-		val = axi_dmac_read(dmac, AXI_DMAC_REG_START_TRANSFER);
-		if (val) /* Queue is full, wait for the next SOT IRQ */
-			return;
-	}
+	val = axi_dmac_read(dmac, AXI_DMAC_REG_START_TRANSFER);
+	if (val) /* Queue is full, wait for the next SOT IRQ */
+		return;
 
 	desc = chan->next_desc;