net: dsa: b53: Properly account for VLAN filtering

VLAN filtering can be built into the kernel, and also dynamically turned
on/off through the bridge master device. Allow re-configuring the switch
appropriately to account for that by deciding whether VLAN table
(v_table) misses should lead to a drop or forward.

Fixes: a2482d2c ("net: dsa: b53: Plug in VLAN support")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/b53/b53_common.c

@@ -344,7 +344,8 @@ static void b53_set_forwarding(struct b53_device *dev, int enable)
 	b53_write8(dev, B53_CTRL_PAGE, B53_SWITCH_CTRL, mgmt);
 }
 
-static void b53_enable_vlan(struct b53_device *dev, bool enable)
+static void b53_enable_vlan(struct b53_device *dev, bool enable,
+			    bool enable_filtering)
 {
 	u8 mgmt, vc0, vc1, vc4 = 0, vc5;
 
@@ -369,8 +370,13 @@ static void b53_enable_vlan(struct b53_device *dev, bool enable)
 		vc0 |= VC0_VLAN_EN | VC0_VID_CHK_EN | VC0_VID_HASH_VID;
 		vc1 |= VC1_RX_MCST_UNTAG_EN | VC1_RX_MCST_FWD_EN;
 		vc4 &= ~VC4_ING_VID_CHECK_MASK;
+		if (enable_filtering) {
 			vc4 |= VC4_ING_VID_VIO_DROP << VC4_ING_VID_CHECK_S;
 			vc5 |= VC5_DROP_VTABLE_MISS;
+		} else {
+			vc4 |= VC4_ING_VID_VIO_FWD << VC4_ING_VID_CHECK_S;
+			vc5 &= ~VC5_DROP_VTABLE_MISS;
+		}
 
 		if (is5325(dev))
 			vc0 &= ~VC0_RESERVED_1;
@@ -420,6 +426,9 @@ static void b53_enable_vlan(struct b53_device *dev, bool enable)
 	}
 
 	b53_write8(dev, B53_CTRL_PAGE, B53_SWITCH_MODE, mgmt);
+
+	dev->vlan_enabled = enable;
+	dev->vlan_filtering_enabled = enable_filtering;
 }
 
 static int b53_set_jumbo(struct b53_device *dev, bool enable, bool allow_10_100)
@@ -656,7 +665,7 @@ int b53_configure_vlan(struct dsa_switch *ds)
 		b53_do_vlan_op(dev, VTA_CMD_CLEAR);
 	}
 
-	b53_enable_vlan(dev, false);
+	b53_enable_vlan(dev, false, dev->vlan_filtering_enabled);
 
 	b53_for_each_port(dev, i)
 		b53_write16(dev, B53_VLAN_PAGE,
@@ -1265,6 +1274,46 @@ EXPORT_SYMBOL(b53_phylink_mac_link_up);
 
 int b53_vlan_filtering(struct dsa_switch *ds, int port, bool vlan_filtering)
 {
+	struct b53_device *dev = ds->priv;
+	struct net_device *bridge_dev;
+	unsigned int i;
+	u16 pvid, new_pvid;
+
+	/* Handle the case were multiple bridges span the same switch device
+	 * and one of them has a different setting than what is being requested
+	 * which would be breaking filtering semantics for any of the other
+	 * bridge devices.
+	 */
+	b53_for_each_port(dev, i) {
+		bridge_dev = dsa_to_port(ds, i)->bridge_dev;
+		if (bridge_dev &&
+		    bridge_dev != dsa_to_port(ds, port)->bridge_dev &&
+		    br_vlan_enabled(bridge_dev) != vlan_filtering) {
+			netdev_err(bridge_dev,
+				   "VLAN filtering is global to the switch!\n");
+			return -EINVAL;
+		}
+	}
+
+	b53_read16(dev, B53_VLAN_PAGE, B53_VLAN_PORT_DEF_TAG(port), &pvid);
+	new_pvid = pvid;
+	if (dev->vlan_filtering_enabled && !vlan_filtering) {
+		/* Filtering is currently enabled, use the default PVID since
+		 * the bridge does not expect tagging anymore
+		 */
+		dev->ports[port].pvid = pvid;
+		new_pvid = b53_default_pvid(dev);
+	} else if (!dev->vlan_filtering_enabled && vlan_filtering) {
+		/* Filtering is currently disabled, restore the previous PVID */
+		new_pvid = dev->ports[port].pvid;
+	}
+
+	if (pvid != new_pvid)
+		b53_write16(dev, B53_VLAN_PAGE, B53_VLAN_PORT_DEF_TAG(port),
+			    new_pvid);
+
+	b53_enable_vlan(dev, dev->vlan_enabled, vlan_filtering);
+
 	return 0;
 }
 EXPORT_SYMBOL(b53_vlan_filtering);
@@ -1280,7 +1329,7 @@ int b53_vlan_prepare(struct dsa_switch *ds, int port,
 	if (vlan->vid_end > dev->num_vlans)
 		return -ERANGE;
 
-	b53_enable_vlan(dev, true);
+	b53_enable_vlan(dev, true, dev->vlan_filtering_enabled);
 
 	return 0;
 }

drivers/net/dsa/b53/b53_priv.h

@@ -91,6 +91,7 @@ enum {
 struct b53_port {
 	u16		vlan_ctl_mask;
 	struct ethtool_eee eee;
+	u16		pvid;
 };
 
 struct b53_vlan {
@@ -137,6 +138,8 @@ struct b53_device {
 
 	unsigned int num_vlans;
 	struct b53_vlan *vlans;
+	bool vlan_enabled;
+	bool vlan_filtering_enabled;
 	unsigned int num_ports;
 	struct b53_port *ports;
 };