[PATCH 14/14] net: ethernet: mtk_eth_soc: drop packets to WDMA if the ring is full

[Felix Fietkau]

Improves handling of DMA ring overflow.
Clarify other WDMA drop related comment.

Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 5 ++++-
 drivers/net/ethernet/mediatek/mtk_eth_soc.h | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 50756c8aa871..4bd06ab1a2b5 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -3529,9 +3529,12 @@ static int mtk_hw_init(struct mtk_eth *eth)
 	mtk_w32(eth, 0x21021000, MTK_FE_INT_GRP);
 
 	if (MTK_HAS_CAPS(eth->soc->caps, MTK_NETSYS_V2)) {
-		/* PSE should not drop port8 and port9 packets */
+		/* PSE should not drop port8 and port9 packets from WDMA Tx */
 		mtk_w32(eth, 0x00000300, PSE_DROP_CFG);
 
+		/* PSE should drop packets to port 8/9 on WDMA Rx ring full */
+		mtk_w32(eth, 0x00000300, PSE_PPE0_DROP);
+
 		/* PSE Free Queue Flow Control  */
 		mtk_w32(eth, 0x01fa01f4, PSE_FQFC_CFG2);
 
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index bf8c7d11df9f..226022346369 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -124,6 +124,7 @@
 #define PSE_FQFC_CFG1		0x100
 #define PSE_FQFC_CFG2		0x104
 #define PSE_DROP_CFG		0x108
+#define PSE_PPE0_DROP		0x110
 
 /* PSE Input Queue Reservation Register*/
 #define PSE_IQ_REV(x)		(0x140 + (((x) - 1) << 2))
-- 
2.38.1