net-next: mediatek: add RX IRQ delay support

The PDMA engine used for RX allows IRQ aggregation. The patch sets up the
corresponding registers to aggregate 4 IRQs into one. Using aggregation
reduces the load on the core handling to a quarter thus reducing IRQ
latency and increasing RX performance by around 10%.

Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index 3c46a3b..e130c3b 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -125,7 +125,14 @@
 #define MTK_PST_DRX_IDX_CFG(x)	(MTK_PST_DRX_IDX0 << (x))
 
 /* PDMA Delay Interrupt Register */
-#define MTK_PDMA_DELAY_INT	0xa0c
+#define MTK_PDMA_DELAY_INT		0xa0c
+#define MTK_PDMA_DELAY_RX_EN		BIT(15)
+#define MTK_PDMA_DELAY_RX_PINT		4
+#define MTK_PDMA_DELAY_RX_PINT_SHIFT	8
+#define MTK_PDMA_DELAY_RX_PTIME		4
+#define MTK_PDMA_DELAY_RX_DELAY		\
+	(MTK_PDMA_DELAY_RX_EN | MTK_PDMA_DELAY_RX_PTIME | \
+	(MTK_PDMA_DELAY_RX_PINT << MTK_PDMA_DELAY_RX_PINT_SHIFT))
 
 /* PDMA Interrupt Status Register */
 #define MTK_PDMA_INT_STATUS	0xa20
@@ -206,6 +213,7 @@
 
 /* QDMA Interrupt Status Register */
 #define MTK_QMTK_INT_STATUS	0x1A18
+#define MTK_RX_DONE_DLY		BIT(30)
 #define MTK_RX_DONE_INT3	BIT(19)
 #define MTK_RX_DONE_INT2	BIT(18)
 #define MTK_RX_DONE_INT1	BIT(17)
@@ -214,8 +222,7 @@
 #define MTK_TX_DONE_INT2	BIT(2)
 #define MTK_TX_DONE_INT1	BIT(1)
 #define MTK_TX_DONE_INT0	BIT(0)
-#define MTK_RX_DONE_INT		(MTK_RX_DONE_INT0 | MTK_RX_DONE_INT1 | \
-				 MTK_RX_DONE_INT2 | MTK_RX_DONE_INT3)
+#define MTK_RX_DONE_INT		MTK_RX_DONE_DLY
 #define MTK_TX_DONE_INT		(MTK_TX_DONE_INT0 | MTK_TX_DONE_INT1 | \
 				 MTK_TX_DONE_INT2 | MTK_TX_DONE_INT3)