ASoC: rcar: clear DE bit only in PDMACHCR when it stops

R-Car datasheet indicates "Clear DE in PDMACHCR" for transfer stop,
but current code clears all bits in PDMACHCR.
Because of this, DE bit might never been cleared,
and it causes CMD overflow. This patch fixes this issue.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sh/rcar/dma.c

@@ -454,6 +454,20 @@ static u32 rsnd_dmapp_read(struct rsnd_dma *dma, u32 reg)
 	return ioread32(rsnd_dmapp_addr(dmac, dma, reg));
 }
 
+static void rsnd_dmapp_bset(struct rsnd_dma *dma, u32 data, u32 mask, u32 reg)
+{
+	struct rsnd_mod *mod = rsnd_mod_get(dma);
+	struct rsnd_priv *priv = rsnd_mod_to_priv(mod);
+	struct rsnd_dma_ctrl *dmac = rsnd_priv_to_dmac(priv);
+	volatile void __iomem *addr = rsnd_dmapp_addr(dmac, dma, reg);
+	u32 val = ioread32(addr);
+
+	val &= ~mask;
+	val |= (data & mask);
+
+	iowrite32(val, addr);
+}
+
 static int rsnd_dmapp_stop(struct rsnd_mod *mod,
 			   struct rsnd_dai_stream *io,
 			   struct rsnd_priv *priv)
@@ -461,10 +475,10 @@ static int rsnd_dmapp_stop(struct rsnd_mod *mod,
 	struct rsnd_dma *dma = rsnd_mod_to_dma(mod);
 	int i;
 
-	rsnd_dmapp_write(dma, 0, PDMACHCR);
+	rsnd_dmapp_bset(dma, 0,  PDMACHCR_DE, PDMACHCR);
 
 	for (i = 0; i < 1024; i++) {
-		if (0 == rsnd_dmapp_read(dma, PDMACHCR))
+		if (0 == (rsnd_dmapp_read(dma, PDMACHCR) & PDMACHCR_DE))
 			return 0;
 		udelay(1);
 	}