[PATCH net,v3 3/3] net: ethernet: mediatek: Enable GDM GDMA_DROP_ALL mode

[MarkLee]

Enable GDM GDMA_DROP_ALL mode to drop all packet during the 
stop operation. This is recommended by the mt762x HW design 
to drop all packet from GMAC before stopping PDMA.

Signed-off-by: MarkLee <Mark-MC.Lee@xxxxxxxxxxxx>
--
v1->v2:
* no change
v2->v3:
* no change

---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 2 ++
 drivers/net/ethernet/mediatek/mtk_eth_soc.h | 1 +
 2 files changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index b147ab0e44ce..5fe1ab0c16cc 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -2279,6 +2279,8 @@ static int mtk_stop(struct net_device *dev)
 	if (!refcount_dec_and_test(&eth->dma_refcnt))
 		return 0;
 
+	mtk_gdm_config(eth, MTK_GDMA_DROP_ALL);
+
 	mtk_tx_irq_disable(eth, MTK_TX_DONE_INT);
 	mtk_rx_irq_disable(eth, MTK_RX_DONE_INT);
 	napi_disable(&eth->tx_napi);
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index b16d8d9b196a..85830fe14a1b 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -85,6 +85,7 @@
 #define MTK_GDMA_TCS_EN		BIT(21)
 #define MTK_GDMA_UCS_EN		BIT(20)
 #define MTK_GDMA_TO_PDMA	0x0
+#define MTK_GDMA_DROP_ALL       0x7777
 
 /* Unicast Filter MAC Address Register - Low */
 #define MTK_GDMA_MAC_ADRL(x)	(0x508 + (x * 0x1000))
-- 
2.17.1