ramips: implement vlan rx offload on MT7621

Avoids the overhead of software VLAN untagging in the network stack

Signed-off-by: Felix Fietkau <nbd@nbd.name>

target/linux/ramips/files-4.14/drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -933,6 +933,11 @@ static int fe_poll_rx(struct napi_struct *napi, int budget,
 			skb_checksum_none_assert(skb);
 		skb->protocol = eth_type_trans(skb, netdev);
 
+		if (netdev->features & NETIF_F_HW_VLAN_CTAG_RX &&
+		    RX_DMA_VID(trxd.rxd3))
+			__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
+					       RX_DMA_VID(trxd.rxd3));
+
 #ifdef CONFIG_NET_MEDIATEK_OFFLOAD
 		if (mtk_offload_check_rx(priv, skb, trxd.rxd4) == 0) {
 #endif
@@ -1585,7 +1590,9 @@ static int fe_probe(struct platform_device *pdev)
 
 	if (soc->init_data)
 		soc->init_data(soc, netdev);
-	netdev->vlan_features = netdev->hw_features & ~NETIF_F_HW_VLAN_CTAG_TX;
+	netdev->vlan_features = netdev->hw_features &
+				~(NETIF_F_HW_VLAN_CTAG_TX |
+				  NETIF_F_HW_VLAN_CTAG_RX);
 	netdev->features |= netdev->hw_features;
 
 	if (IS_ENABLED(CONFIG_SOC_MT7621))

target/linux/ramips/files-4.14/drivers/net/ethernet/mediatek/mtk_eth_soc.h

@@ -406,7 +406,6 @@ struct fe_soc_data {
 #define FE_FLAG_JUMBO_FRAME		BIT(2)
 #define FE_FLAG_RX_2B_OFFSET		BIT(3)
 #define FE_FLAG_RX_SG_DMA		BIT(4)
-#define FE_FLAG_RX_VLAN_CTAG		BIT(5)
 #define FE_FLAG_NAPI_WEIGHT		BIT(6)
 #define FE_FLAG_CALIBRATE_CLK		BIT(7)
 #define FE_FLAG_HAS_SWITCH		BIT(8)

target/linux/ramips/files-4.14/drivers/net/ethernet/mediatek/soc_mt7621.c

@@ -122,7 +122,7 @@ static int mt7621_fwd_config(struct fe_priv *priv)
 
 	/* mt7621 doesn't have txcsum config */
 	mt7621_rxcsum_config((dev->features & NETIF_F_RXCSUM));
-	mt7621_rxvlan_config(priv->flags & FE_FLAG_RX_VLAN_CTAG);
+	mt7621_rxvlan_config(dev->features & NETIF_F_HW_VLAN_CTAG_RX);
 
 	return 0;
 }
@@ -142,7 +142,8 @@ static void mt7621_init_data(struct fe_soc_data *data,
 		FE_FLAG_HAS_SWITCH | FE_FLAG_JUMBO_FRAME;
 
 	netdev->hw_features = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
-		NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_SG | NETIF_F_TSO |
+		NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX |
+		NETIF_F_SG | NETIF_F_TSO |
 		NETIF_F_TSO6 | NETIF_F_IPV6_CSUM |
 		NETIF_F_TSO_MANGLEID;
 }