mt76: mt7921: add back connection monitor support

Hw beacon cmd to the mt7921 firmware doesn't only filter out the beacon,
but also performs its own connection monitoring, including periodic
keep-alives to the AP and probing the AP on beacon loss. Will indicate
the host with the event when the firmware detects the connection is lost.

Fixes: 1d8efc74 ("mt76: mt7921: introduce Runtime PM support")
Reviewed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
Signed-off-by: YN Chen <yn.chen@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7921/init.c

@@ -45,6 +45,7 @@ static void
 mt7921_init_wiphy(struct ieee80211_hw *hw)
 {
 	struct mt7921_phy *phy = mt7921_hw_phy(hw);
+	struct mt7921_dev *dev = phy->dev;
 	struct wiphy *wiphy = hw->wiphy;
 
 	hw->queues = 4;
@@ -84,6 +85,9 @@ mt7921_init_wiphy(struct ieee80211_hw *hw)
 	ieee80211_hw_set(hw, SUPPORTS_PS);
 	ieee80211_hw_set(hw, SUPPORTS_DYNAMIC_PS);
 
+	if (dev->pm.enable)
+		ieee80211_hw_set(hw, CONNECTION_MONITOR);
+
 	hw->max_tx_fragments = 4;
 }
 

drivers/net/wireless/mediatek/mt76/mt7921/mcu.c

@@ -450,22 +450,33 @@ mt7921_mcu_scan_event(struct mt7921_dev *dev, struct sk_buff *skb)
 }
 
 static void
-mt7921_mcu_beacon_loss_event(struct mt7921_dev *dev, struct sk_buff *skb)
+mt7921_mcu_connection_loss_iter(void *priv, u8 *mac,
+				struct ieee80211_vif *vif)
+{
+	struct mt76_vif *mvif = (struct mt76_vif *)vif->drv_priv;
+	struct mt76_connac_beacon_loss_event *event = priv;
+
+	if (mvif->idx != event->bss_idx)
+		return;
+
+	if (!(vif->driver_flags & IEEE80211_VIF_BEACON_FILTER))
+		return;
+
+	ieee80211_connection_loss(vif);
+}
+
+static void
+mt7921_mcu_connection_loss_event(struct mt7921_dev *dev, struct sk_buff *skb)
 {
 	struct mt76_connac_beacon_loss_event *event;
-	struct mt76_phy *mphy;
-	u8 band_idx = 0; /* DBDC support */
+	struct mt76_phy *mphy = &dev->mt76.phy;
 
 	skb_pull(skb, sizeof(struct mt7921_mcu_rxd));
 	event = (struct mt76_connac_beacon_loss_event *)skb->data;
-	if (band_idx && dev->mt76.phy2)
-		mphy = dev->mt76.phy2;
-	else
-		mphy = &dev->mt76.phy;
 
 	ieee80211_iterate_active_interfaces_atomic(mphy->hw,
 					IEEE80211_IFACE_ITER_RESUME_ALL,
-					mt76_connac_mcu_beacon_loss_iter, event);
+					mt7921_mcu_connection_loss_iter, event);
 }
 
 static void
@@ -530,7 +541,7 @@ mt7921_mcu_rx_unsolicited_event(struct mt7921_dev *dev, struct sk_buff *skb)
 
 	switch (rxd->eid) {
 	case MCU_EVENT_BSS_BEACON_LOSS:
-		mt7921_mcu_beacon_loss_event(dev, skb);
+		mt7921_mcu_connection_loss_event(dev, skb);
 		break;
 	case MCU_EVENT_SCHED_SCAN_DONE:
 	case MCU_EVENT_SCAN_DONE:
@@ -1379,6 +1390,7 @@ mt7921_pm_interface_iter(void *priv, u8 *mac, struct ieee80211_vif *vif)
 {
 	struct mt7921_phy *phy = priv;
 	struct mt7921_dev *dev = phy->dev;
+	struct ieee80211_hw *hw = mt76_hw(dev);
 	int ret;
 
 	if (dev->pm.enable)
@@ -1391,9 +1403,11 @@ mt7921_pm_interface_iter(void *priv, u8 *mac, struct ieee80211_vif *vif)
 
 	if (dev->pm.enable) {
 		vif->driver_flags |= IEEE80211_VIF_BEACON_FILTER;
+		ieee80211_hw_set(hw, CONNECTION_MONITOR);
 		mt76_set(dev, MT_WF_RFCR(0), MT_WF_RFCR_DROP_OTHER_BEACON);
 	} else {
 		vif->driver_flags &= ~IEEE80211_VIF_BEACON_FILTER;
+		__clear_bit(IEEE80211_HW_CONNECTION_MONITOR, hw->flags);
 		mt76_clear(dev, MT_WF_RFCR(0), MT_WF_RFCR_DROP_OTHER_BEACON);
 	}
 }