mt76x02: use mask for vifs

Use vif_mask to count interfaces to allow to set mac address in HW
if there is only one interface and report error if we create
interface with wrong BSSID resulting in already used index.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt76x02.h

@@ -73,6 +73,8 @@ struct mt76x02_dev {
 
 	struct mutex phy_mutex;
 
+	u16 vif_mask;
+
 	u8 txdone_seq;
 	DECLARE_KFIFO_PTR(txstatus_fifo, struct mt76x02_tx_status);
 

drivers/net/wireless/mediatek/mt76/mt76x02_util.c

@@ -309,6 +309,15 @@ mt76x02_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 	if (vif->type == NL80211_IFTYPE_STATION)
 		idx += 8;
 
+	if (dev->vif_mask & BIT(idx))
+		return -EBUSY;
+
+	/* Allow to change address in HW if we create first interface. */
+	if (!dev->vif_mask && !ether_addr_equal(dev->mt76.macaddr, vif->addr))
+                mt76x02_mac_setaddr(dev, vif->addr);
+
+	dev->vif_mask |= BIT(idx);
+
 	mt76x02_vif_init(dev, vif, idx);
 	return 0;
 }
@@ -318,8 +327,10 @@ void mt76x02_remove_interface(struct ieee80211_hw *hw,
 			      struct ieee80211_vif *vif)
 {
 	struct mt76x02_dev *dev = hw->priv;
+	struct mt76x02_vif *mvif = (struct mt76x02_vif *)vif->drv_priv;
 
 	mt76_txq_remove(&dev->mt76, vif->txq);
+	dev->vif_mask &= ~BIT(mvif->idx);
 }
 EXPORT_SYMBOL_GPL(mt76x02_remove_interface);