enetc: permit configuration of rx-vlan-filter with ethtool

Each ENETC station interface (SI) has a VLAN filter list and a port
flag (PSIPVMR) by which it can be put in "VLAN promiscuous" mode, which
enables the reception of VLAN-tagged traffic even if it is not in the
VLAN filtering list.

Currently the handling of this setting works like this: the port starts
off as VLAN promiscuous, then it switches to enabling VLAN filtering as
soon as the first VLAN is installed in its filter via
.ndo_vlan_rx_add_vid. In practice that does not work out very well,
because more often than not, the first VLAN to be installed is out of
the control of the user: the 8021q module, if loaded, adds its rule for
802.1p (VID 0) traffic upon bringing the interface up.

What the user is currently seeing in ethtool is this:
ethtool -k eno2
rx-vlan-filter: on [fixed]

which doesn't match the intention of the code, but the practical reality
of having the 8021q module install its VID which has the side-effect of
turning on VLAN filtering in this driver. All in all, a slightly
confusing experience.

So instead of letting this driver switch the VLAN filtering state by
itself, just wire it up with the rx-vlan-filter feature from ethtool,
and let it be user-configurable just through that knob, except for one
case, see below.

In promiscuous mode, it is more intuitive that all traffic is received,
including VLAN tagged traffic. It appears that it is necessary to set
the flag in PSIPVMR for that to be the case, so VLAN promiscuous mode is
also temporarily enabled. On exit from promiscuous mode, the setting
made by ethtool is restored.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/enetc/enetc_pf.c

@@ -50,21 +50,6 @@ static void enetc_set_vlan_promisc(struct enetc_hw *hw, char si_map)
 	enetc_port_wr(hw, ENETC_PSIPVMR, ENETC_PSIPVMR_SET_VP(si_map) | val);
 }
 
-static bool enetc_si_vlan_promisc_is_on(struct enetc_pf *pf, int si_idx)
-{
-	return pf->vlan_promisc_simap & BIT(si_idx);
-}
-
-static bool enetc_vlan_filter_is_on(struct enetc_pf *pf)
-{
-	int i;
-
-	for_each_set_bit(i, pf->active_vlans, VLAN_N_VID)
-		return true;
-
-	return false;
-}
-
 static void enetc_enable_si_vlan_promisc(struct enetc_pf *pf, int si_idx)
 {
 	pf->vlan_promisc_simap |= BIT(si_idx);
@@ -204,6 +189,7 @@ static void enetc_pf_set_rx_mode(struct net_device *ndev)
 {
 	struct enetc_ndev_priv *priv = netdev_priv(ndev);
 	struct enetc_pf *pf = enetc_si_priv(priv->si);
+	char vlan_promisc_simap = pf->vlan_promisc_simap;
 	struct enetc_hw *hw = &priv->si->hw;
 	bool uprom = false, mprom = false;
 	struct enetc_mac_filter *filter;
@@ -216,16 +202,16 @@ static void enetc_pf_set_rx_mode(struct net_device *ndev)
 		psipmr = ENETC_PSIPMR_SET_UP(0) | ENETC_PSIPMR_SET_MP(0);
 		uprom = true;
 		mprom = true;
-		/* enable VLAN promisc mode for SI0 */
-		if (!enetc_si_vlan_promisc_is_on(pf, 0))
-			enetc_enable_si_vlan_promisc(pf, 0);
-
+		/* Enable VLAN promiscuous mode for SI0 (PF) */
+		vlan_promisc_simap |= BIT(0);
 	} else if (ndev->flags & IFF_ALLMULTI) {
 		/* enable multi cast promisc mode for SI0 (PF) */
 		psipmr = ENETC_PSIPMR_SET_MP(0);
 		mprom = true;
 	}
 
+	enetc_set_vlan_promisc(&pf->si->hw, vlan_promisc_simap);
+
 	/* first 2 filter entries belong to PF */
 	if (!uprom) {
 		/* Update unicast filters */
@@ -306,9 +292,6 @@ static int enetc_vlan_rx_add_vid(struct net_device *ndev, __be16 prot, u16 vid)
 	struct enetc_pf *pf = enetc_si_priv(priv->si);
 	int idx;
 
-	if (enetc_si_vlan_promisc_is_on(pf, 0))
-		enetc_disable_si_vlan_promisc(pf, 0);
-
 	__set_bit(vid, pf->active_vlans);
 
 	idx = enetc_vid_hash_idx(vid);
@@ -326,9 +309,6 @@ static int enetc_vlan_rx_del_vid(struct net_device *ndev, __be16 prot, u16 vid)
 	__clear_bit(vid, pf->active_vlans);
 	enetc_sync_vlan_ht_filter(pf, true);
 
-	if (!enetc_vlan_filter_is_on(pf))
-		enetc_enable_si_vlan_promisc(pf, 0);
-
 	return 0;
 }
 
@@ -677,6 +657,15 @@ static int enetc_pf_set_features(struct net_device *ndev,
 		enetc_enable_txvlan(&priv->si->hw, 0,
 				    !!(features & NETIF_F_HW_VLAN_CTAG_TX));
 
+	if (changed & NETIF_F_HW_VLAN_CTAG_FILTER) {
+		struct enetc_pf *pf = enetc_si_priv(priv->si);
+
+		if (!!(features & NETIF_F_HW_VLAN_CTAG_FILTER))
+			enetc_disable_si_vlan_promisc(pf, 0);
+		else
+			enetc_enable_si_vlan_promisc(pf, 0);
+	}
+
 	if (changed & NETIF_F_LOOPBACK)
 		enetc_set_loopback(ndev, !!(features & NETIF_F_LOOPBACK));
 
@@ -719,12 +708,11 @@ static void enetc_pf_netdev_setup(struct enetc_si *si, struct net_device *ndev,
 
 	ndev->hw_features = NETIF_F_SG | NETIF_F_RXCSUM | NETIF_F_HW_CSUM |
 			    NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX |
-			    NETIF_F_LOOPBACK;
+			    NETIF_F_HW_VLAN_CTAG_FILTER | NETIF_F_LOOPBACK;
 	ndev->features = NETIF_F_HIGHDMA | NETIF_F_SG |
 			 NETIF_F_RXCSUM | NETIF_F_HW_CSUM |
 			 NETIF_F_HW_VLAN_CTAG_TX |
-			 NETIF_F_HW_VLAN_CTAG_RX |
-			 NETIF_F_HW_VLAN_CTAG_FILTER;
+			 NETIF_F_HW_VLAN_CTAG_RX;
 
 	if (si->num_rss)
 		ndev->hw_features |= NETIF_F_RXHASH;