[PATCH 11/14] net: ethernet: mtk_eth_soc: fix VLAN rx hardware acceleration

[Felix Fietkau]

- enable VLAN untagging for PDMA rx
- make it possible to disable the feature via ethtool
- pass VLAN tag to the DSA driver
- untag special tag on PDMA only if no non-DSA devices are in use
- disable special tag untagging on 7986 for now, since it's not working yet

Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 36 +++++++++++++--------
 drivers/net/ethernet/mediatek/mtk_eth_soc.h |  3 ++
 2 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index ab31dda2cd66..3b8995a483aa 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -2015,16 +2015,9 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
 						htons(RX_DMA_VPID(trxd.rxd4)),
 						RX_DMA_VID(trxd.rxd4));
 			} else if (trxd.rxd2 & RX_DMA_VTAG) {
-				__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
+				__vlan_hwaccel_put_tag(skb, htons(RX_DMA_VPID(trxd.rxd3)),
 						       RX_DMA_VID(trxd.rxd3));
 			}
-
-			/* If the device is attached to a dsa switch, the special
-			 * tag inserted in VLAN field by hw switch can * be offloaded
-			 * by RX HW VLAN offload. Clear vlan info.
-			 */
-			if (netdev_uses_dsa(netdev))
-				__vlan_hwaccel_clear_tag(skb);
 		}
 
 		skb_record_rx_queue(skb, 0);
@@ -2847,15 +2840,17 @@ static netdev_features_t mtk_fix_features(struct net_device *dev,
 
 static int mtk_set_features(struct net_device *dev, netdev_features_t features)
 {
-	int err = 0;
-
-	if (!((dev->features ^ features) & NETIF_F_LRO))
-		return 0;
+	struct mtk_mac *mac = netdev_priv(dev);
+	struct mtk_eth *eth = mac->hw;
+	netdev_features_t diff = dev->features ^ features;
 
-	if (!(features & NETIF_F_LRO))
+	if ((diff & NETIF_F_LRO) && !(features & NETIF_F_LRO))
 		mtk_hwlro_netdev_disable(dev);
 
-	return err;
+	/* Set RX VLAN offloading */
+	mtk_w32(eth, !!(features & NETIF_F_HW_VLAN_CTAG_RX), MTK_CDMP_EG_CTRL);
+
+	return 0;
 }
 
 /* wait for DMA to finish whatever it is doing before we start using it again */
@@ -3176,6 +3171,15 @@ static int mtk_open(struct net_device *dev)
 	else
 		refcount_inc(&eth->dma_refcnt);
 
+	/* Hardware special tag parsing needs to be disabled if at least
+	 * one MAC does not use DSA.
+	 */
+	if (!netdev_uses_dsa(dev)) {
+		u32 val = mtk_r32(eth, MTK_CDMP_IG_CTRL);
+		val &= ~MTK_CDMP_STAG_EN;
+		mtk_w32(eth, val, MTK_CDMP_IG_CTRL);
+	}
+
 	phylink_start(mac->phylink);
 	netif_tx_start_all_queues(dev);
 
@@ -3469,6 +3473,10 @@ static int mtk_hw_init(struct mtk_eth *eth)
 	 */
 	val = mtk_r32(eth, MTK_CDMQ_IG_CTRL);
 	mtk_w32(eth, val | MTK_CDMQ_STAG_EN, MTK_CDMQ_IG_CTRL);
+	if (MTK_HAS_CAPS(eth->soc->caps, MTK_NETSYS_V2)) {
+		val = mtk_r32(eth, MTK_CDMP_IG_CTRL);
+		mtk_w32(eth, val | MTK_CDMP_STAG_EN, MTK_CDMP_IG_CTRL);
+	}
 
 	/* Enable RX VLan Offloading */
 	mtk_w32(eth, 1, MTK_CDMP_EG_CTRL);
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index e09b2483c70c..26b2323185ef 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -93,6 +93,9 @@
 #define MTK_CDMQ_IG_CTRL	0x1400
 #define MTK_CDMQ_STAG_EN	BIT(0)
 
+/* CDMQ Exgress Control Register */
+#define MTK_CDMQ_EG_CTRL	0x1404
+
 /* CDMP Ingress Control Register */
 #define MTK_CDMP_IG_CTRL	0x400
 #define MTK_CDMP_STAG_EN	BIT(0)
-- 
2.38.1