wifi: mt76: mt7915: add ack signal support

This reports signal strength of ACK packets from the peer as measured
at each interface.
Tested-by: Shurong Wen <shurong.wen@mediatek.com>
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mac80211.c

@@ -951,14 +951,12 @@ void mt76_wcid_key_setup(struct mt76_dev *dev, struct mt76_wcid *wcid,
 }
 EXPORT_SYMBOL(mt76_wcid_key_setup);
 
-static int
-mt76_rx_signal(struct mt76_rx_status *status)
+int mt76_rx_signal(u8 chain_mask, s8 *chain_signal)
 {
-	s8 *chain_signal = status->chain_signal;
 	int signal = -128;
 	u8 chains;
 
-	for (chains = status->chains; chains; chains >>= 1, chain_signal++) {
+	for (chains = chain_mask; chains; chains >>= 1, chain_signal++) {
 		int cur, diff;
 
 		cur = *chain_signal;
@@ -980,6 +978,7 @@ mt76_rx_signal(struct mt76_rx_status *status)
 
 	return signal;
 }
+EXPORT_SYMBOL(mt76_rx_signal);
 
 static void
 mt76_rx_convert(struct mt76_dev *dev, struct sk_buff *skb,
@@ -1009,7 +1008,7 @@ mt76_rx_convert(struct mt76_dev *dev, struct sk_buff *skb,
 	status->ampdu_reference = mstat.ampdu_ref;
 	status->device_timestamp = mstat.timestamp;
 	status->mactime = mstat.timestamp;
-	status->signal = mt76_rx_signal(&mstat);
+	status->signal = mt76_rx_signal(mstat.chains, mstat.chain_signal);
 	if (status->signal <= -128)
 		status->flag |= RX_FLAG_NO_SIGNAL_VAL;
 

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

@@ -1149,6 +1149,7 @@ void mt76_update_survey(struct mt76_phy *phy);
 void mt76_update_survey_active_time(struct mt76_phy *phy, ktime_t time);
 int mt76_get_survey(struct ieee80211_hw *hw, int idx,
 		    struct survey_info *survey);
+int mt76_rx_signal(u8 chain_mask, s8 *chain_signal);
 void mt76_set_stream_caps(struct mt76_phy *phy, bool vht);
 
 int mt76_rx_aggr_start(struct mt76_dev *dev, struct mt76_wcid *wcid, u8 tid,

drivers/net/wireless/mediatek/mt76/mt7915/init.c

@@ -353,6 +353,7 @@ mt7915_init_wiphy(struct ieee80211_hw *hw)
 	wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_BEACON_RATE_HE);
 	wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_UNSOL_BCAST_PROBE_RESP);
 	wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_FILS_DISCOVERY);
+	wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_ACK_SIGNAL_SUPPORT);
 
 	if (!mdev->dev->of_node ||
 	    !of_property_read_bool(mdev->dev->of_node,
@@ -461,6 +462,12 @@ mt7915_mac_init_band(struct mt7915_dev *dev, u8 band)
 	set = FIELD_PREP(MT_WF_RMAC_MIB_OBSS_BACKOFF, 0) |
 	      FIELD_PREP(MT_WF_RMAC_MIB_ED_OFFSET, 4);
 	mt76_rmw(dev, MT_WF_RMAC_MIB_AIRTIME0(band), mask, set);
+
+	/* filter out non-resp frames and get instanstaeous signal reporting */
+	mask = MT_WTBLOFF_TOP_RSCR_RCPI_MODE | MT_WTBLOFF_TOP_RSCR_RCPI_PARAM;
+	set = FIELD_PREP(MT_WTBLOFF_TOP_RSCR_RCPI_MODE, 0) |
+	      FIELD_PREP(MT_WTBLOFF_TOP_RSCR_RCPI_PARAM, 0x3);
+	mt76_rmw(dev, MT_WTBLOFF_TOP_RSCR(band), mask, set);
 }
 
 static void mt7915_mac_init(struct mt7915_dev *dev)

drivers/net/wireless/mediatek/mt76/mt7915/mac.c

@@ -8,7 +8,7 @@
 #include "mac.h"
 #include "mcu.h"
 
-#define to_rssi(field, rxv)	((FIELD_GET(field, rxv) - 220) / 2)
+#define to_rssi(field, rcpi)	((FIELD_GET(field, rcpi) - 220) / 2)
 
 static const struct mt7915_dfs_radar_spec etsi_radar_specs = {
 	.pulse_th = { 110, -10, -80, 40, 5200, 128, 5200 },
@@ -118,6 +118,7 @@ static void mt7915_mac_sta_poll(struct mt7915_dev *dev)
 		bool clear = false;
 		u32 addr, val;
 		u16 idx;
+		s8 rssi[4];
 		u8 bw;
 
 		spin_lock_bh(&dev->sta_poll_lock);
@@ -131,6 +132,8 @@ static void mt7915_mac_sta_poll(struct mt7915_dev *dev)
 		spin_unlock_bh(&dev->sta_poll_lock);
 
 		idx = msta->wcid.idx;
+
+		/* refresh peer's airtime reporting */
 		addr = mt7915_mac_wtbl_lmac_addr(dev, idx, 20);
 
 		for (i = 0; i < IEEE80211_NUM_ACS; i++) {
@@ -209,6 +212,20 @@ static void mt7915_mac_sta_poll(struct mt7915_dev *dev)
 			else
 				rate->flags &= ~RATE_INFO_FLAGS_SHORT_GI;
 		}
+
+		/* get signal strength of resp frames (CTS/BA/ACK) */
+		addr = mt7915_mac_wtbl_lmac_addr(dev, idx, 30);
+		val = mt76_rr(dev, addr);
+
+		rssi[0] = to_rssi(GENMASK(7, 0), val);
+		rssi[1] = to_rssi(GENMASK(15, 8), val);
+		rssi[2] = to_rssi(GENMASK(23, 16), val);
+		rssi[3] = to_rssi(GENMASK(31, 14), val);
+
+		msta->ack_signal =
+			mt76_rx_signal(msta->vif->phy->mt76->antenna_mask, rssi);
+
+		ewma_avg_signal_add(&msta->avg_ack_signal, -msta->ack_signal);
 	}
 
 	rcu_read_unlock();

drivers/net/wireless/mediatek/mt76/mt7915/main.c

@@ -665,6 +665,8 @@ int mt7915_mac_sta_add(struct mt76_dev *mdev, struct ieee80211_vif *vif,
 	msta->wcid.tx_info |= MT_WCID_TX_INFO_SET;
 	msta->jiffies = jiffies;
 
+	ewma_avg_signal_init(&msta->avg_ack_signal);
+
 	mt7915_mac_wtbl_update(dev, idx,
 			       MT_WTBL_UPDATE_ADM_COUNT_CLEAR);
 
@@ -1025,6 +1027,12 @@ static void mt7915_sta_statistics(struct ieee80211_hw *hw,
 		sinfo->tx_retries = msta->wcid.stats.tx_retries;
 		sinfo->filled |= BIT_ULL(NL80211_STA_INFO_TX_RETRIES);
 	}
+
+	sinfo->ack_signal = (s8)msta->ack_signal;
+	sinfo->filled |= BIT_ULL(NL80211_STA_INFO_ACK_SIGNAL);
+
+	sinfo->avg_ack_signal = -(s8)ewma_avg_signal_read(&msta->avg_ack_signal);
+	sinfo->filled |= BIT_ULL(NL80211_STA_INFO_ACK_SIGNAL_AVG);
 }
 
 static void mt7915_sta_rc_work(void *data, struct ieee80211_sta *sta)

drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h

@@ -114,6 +114,8 @@ struct mt7915_twt_flow {
 	u8 sched:1;
 };
 
+DECLARE_EWMA(avg_signal, 10, 8)
+
 struct mt7915_sta {
 	struct mt76_wcid wcid; /* must be first */
 
@@ -123,10 +125,12 @@ struct mt7915_sta {
 	struct list_head rc_list;
 	u32 airtime_ac[8];
 
+	int ack_signal;
+	struct ewma_avg_signal avg_ack_signal;
+
 	unsigned long changed;
 	unsigned long jiffies;
 	unsigned long ampdu_state;
-
 	struct mt76_connac_sta_key_conf bip;
 
 	struct {

drivers/net/wireless/mediatek/mt76/mt7915/regs.h

@@ -226,6 +226,14 @@ enum offs_rev {
 #define MT_DMA_DCR0_MAX_RX_LEN		GENMASK(15, 3)
 #define MT_DMA_DCR0_RXD_G5_EN		BIT(23)
 
+/* WTBLOFF TOP: band 0(0x820e9000),band 1(0x820f9000) */
+#define MT_WTBLOFF_TOP_BASE(_band)	((_band) ? 0x820f9000 : 0x820e9000)
+#define MT_WTBLOFF_TOP(_band, ofs)	(MT_WTBLOFF_TOP_BASE(_band) + (ofs))
+
+#define MT_WTBLOFF_TOP_RSCR(_band)	MT_WTBLOFF_TOP(_band, 0x008)
+#define MT_WTBLOFF_TOP_RSCR_RCPI_MODE	GENMASK(31, 30)
+#define MT_WTBLOFF_TOP_RSCR_RCPI_PARAM	GENMASK(25, 24)
+
 /* ETBF: band 0(0x820ea000), band 1(0x820fa000) */
 #define MT_WF_ETBF_BASE(_band)		((_band) ? 0x820fa000 : 0x820ea000)
 #define MT_WF_ETBF(_band, ofs)		(MT_WF_ETBF_BASE(_band) + (ofs))