dmaengine: rcar-dmac: clear channel register when error

We need to clear channel register in error case as recovery.
The channel is already stopped in such case, thus we don't need to call
rcar_dmac_chan_halt() before clearing.

rcar_dmac_chan_halt() will clear and confirm DE bit.
But it will be failed because channel is already stopped in error case.
In other words, we shouldn't call it then.
Reported-by: Hiroki Negishi <hiroki.negishi.bx@renesas.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Hiroki Negishi <hiroki.negishi.bx@renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/sh/rcar-dmac.c

@@ -1522,7 +1522,15 @@ static irqreturn_t rcar_dmac_isr_channel(int irq, void *dev)
 
 	chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
 	if (chcr & RCAR_DMACHCR_CAE) {
-		rcar_dmac_chan_halt(chan);
+		struct rcar_dmac *dmac = to_rcar_dmac(chan->chan.device);
+
+		/*
+		 * We don't need to call rcar_dmac_chan_halt()
+		 * because channel is already stopped in error case.
+		 * We need to clear register and check DE bit as recovery.
+		 */
+		rcar_dmac_write(dmac, RCAR_DMACHCLR, 1 << chan->index);
+		rcar_dmac_chcr_de_barrier(chan);
 		reinit = true;
 		goto spin_lock_end;
 	}