mac80211: average ack rssi support for data frames

The driver will process the RSSI if available and send it to mac80211.
mac80211 will compute the weighted average of ack RSSI for stations.
Signed-off-by: Balaji Pothunoori <bpothuno@codeaurora.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/sta_info.c

@@ -358,6 +358,7 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
 
 	sta->last_connected = ktime_get_seconds();
 	ewma_signal_init(&sta->rx_stats_avg.signal);
+	ewma_avg_signal_init(&sta->status_stats.avg_ack_signal);
 	for (i = 0; i < ARRAY_SIZE(sta->rx_stats_avg.chain_signal); i++)
 		ewma_signal_init(&sta->rx_stats_avg.chain_signal[i]);
 
@@ -2294,6 +2295,15 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
 		sinfo->ack_signal = sta->status_stats.last_ack_signal;
 		sinfo->filled |= BIT_ULL(NL80211_STA_INFO_ACK_SIGNAL);
 	}
+
+	if (ieee80211_hw_check(&sta->local->hw, REPORTS_TX_ACK_STATUS) &&
+	    !(sinfo->filled & BIT_ULL(NL80211_STA_INFO_DATA_ACK_SIGNAL_AVG))) {
+		sinfo->avg_ack_signal =
+			-(s8)ewma_avg_signal_read(
+				&sta->status_stats.avg_ack_signal);
+		sinfo->filled |=
+			BIT_ULL(NL80211_STA_INFO_DATA_ACK_SIGNAL_AVG);
+	}
 }
 
 u32 sta_get_expected_throughput(struct sta_info *sta)

net/mac80211/sta_info.h

@@ -119,6 +119,7 @@ enum ieee80211_sta_info_flags {
 #define HT_AGG_STATE_START_CB		6
 #define HT_AGG_STATE_STOP_CB		7
 
+DECLARE_EWMA(avg_signal, 10, 8)
 enum ieee80211_agg_stop_reason {
 	AGG_STOP_DECLINED,
 	AGG_STOP_LOCAL_REQUEST,
@@ -550,6 +551,7 @@ struct sta_info {
 		unsigned long last_ack;
 		s8 last_ack_signal;
 		bool ack_signal_filled;
+		struct ewma_avg_signal avg_ack_signal;
 	} status_stats;
 
 	/* Updated from TX path only, no locking requirements */

net/mac80211/status.c

@@ -195,6 +195,8 @@ static void ieee80211_frame_acked(struct sta_info *sta, struct sk_buff *skb)
 			sta->status_stats.last_ack_signal =
 					 (s8)txinfo->status.ack_signal;
 			sta->status_stats.ack_signal_filled = true;
+			ewma_avg_signal_add(&sta->status_stats.avg_ack_signal,
+					    -txinfo->status.ack_signal);
 		}
 	}