MIPS: lantiq: dma: fix burst length for DEU

[ Upstream commit 5ad74d3 ]

The current definition of 2W burst length is invalid.
This patch fixes it. Current downstream DEU driver doesn't
use DMA. An incorrect burst length value doesn't cause any
errors. This patch also adds other burst length values.

Fixes: dfec1a8 ("MIPS: Lantiq: Add DMA support")
Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

arch/mips/lantiq/xway/dma.c

@@ -41,7 +41,11 @@
 #define DMA_IRQ_ACK		0x7e		/* IRQ status register */
 #define DMA_POLL		BIT(31)		/* turn on channel polling */
 #define DMA_CLK_DIV4		BIT(6)		/* polling clock divider */
-#define DMA_2W_BURST		BIT(1)		/* 2 word burst length */
+#define DMA_PCTRL_2W_BURST	0x1		/* 2 word burst length */
+#define DMA_PCTRL_4W_BURST	0x2		/* 4 word burst length */
+#define DMA_PCTRL_8W_BURST	0x3		/* 8 word burst length */
+#define DMA_TX_BURST_SHIFT	4		/* tx burst shift */
+#define DMA_RX_BURST_SHIFT	2		/* rx burst shift */
 #define DMA_ETOP_ENDIANNESS	(0xf << 8) /* endianness swap etop channels */
 #define DMA_WEIGHT	(BIT(17) | BIT(16))	/* default channel wheight */
 
@@ -192,7 +196,8 @@ ltq_dma_init_port(int p)
 		break;
 
 	case DMA_PORT_DEU:
-		ltq_dma_w32((DMA_2W_BURST << 4) | (DMA_2W_BURST << 2),
+		ltq_dma_w32((DMA_PCTRL_2W_BURST << DMA_TX_BURST_SHIFT) |
+			(DMA_PCTRL_2W_BURST << DMA_RX_BURST_SHIFT),
 			LTQ_DMA_PCTRL);
 		break;