[PATCH net v6 4/5] net: stmmac: Do not advertise S-VLAN stripping when it is disabled

[Ovidiu Panait <ovidiu.panait.rb@renesas.com>]

C-VLAN and S-VLAN tag stripping are both controlled by the EVLS bit,
so disabling rx-vlan-offload also disables S-VLAN tag stripping.
However, rx-vlan-stag-hw-parse keeps being advertised as enabled:

root@rzv2h-evk:~# ethtool -K end1 rx-vlan-offload off
root@rzv2h-evk:~# ethtool -k end1 | grep -i vlan
rx-vlan-offload: off
tx-vlan-offload: off [fixed]
rx-vlan-filter: on [fixed]
vlan-challenged: off [fixed]
tx-vlan-stag-hw-insert: off [fixed]
rx-vlan-stag-hw-parse: on [fixed]
rx-vlan-stag-filter: on [fixed]

Fix this inconsistency by making NETIF_F_HW_VLAN_STAG_RX follow
NETIF_F_HW_VLAN_CTAG_RX.

Fixes: 750011e239a5 ("net: stmmac: Add support for HW-accelerated VLAN stripping")
Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
---
v6 changes: None.

v5 changes:
- Rebased on top of the rename patch: used dwmac_is_xmac() instead of
  the dropped hw_svlan_en flag.

v4 changes:
- New patch.

 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 0d70eb452af7..b007ff120471 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -6211,6 +6211,13 @@ static netdev_features_t stmmac_fix_features(struct net_device *dev,
 	if (priv->plat->bugged_jumbo && (dev->mtu > ETH_DATA_LEN))
 		features &= ~NETIF_F_CSUM_MASK;
 
+	if (dwmac_is_xmac(priv->plat->core_type)) {
+		if (features & NETIF_F_HW_VLAN_CTAG_RX)
+			features |= NETIF_F_HW_VLAN_STAG_RX;
+		else
+			features &= ~NETIF_F_HW_VLAN_STAG_RX;
+	}
+
 	return features;
 }
 
-- 
2.34.1