[RFC] mac80211: add debugfs file for last ack signal

[Saravana <saravanad@posedge.com>]

Add a debugfs file showing the signal strength
of the ack frame that is received for the
currently sent tx packet

Signed-off-by: Saravana <saravanad@posedge.com>
---
 net/mac80211/debugfs_sta.c |    2 ++
 net/mac80211/sta_info.h    |    2 ++
 net/mac80211/status.c      |    3 +++
 3 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c
index 89281d2..1566941 100644
--- a/net/mac80211/debugfs_sta.c
+++ b/net/mac80211/debugfs_sta.c
@@ -53,6 +53,7 @@ static const struct file_operations sta_ ##name## _ops = {		\
 STA_FILE(aid, sta.aid, D);
 STA_FILE(dev, sdata->name, S);
 STA_FILE(last_signal, last_signal, D);
+STA_FILE(last_ack_signal, last_ack_signal, D);
 
 static ssize_t sta_flags_read(struct file *file, char __user *userbuf,
 			      size_t count, loff_t *ppos)
@@ -369,6 +370,7 @@ void ieee80211_sta_debugfs_add(struct sta_info *sta)
 	DEBUGFS_ADD(dev);
 	DEBUGFS_ADD(last_signal);
 	DEBUGFS_ADD(ht_capa);
+	DEBUGFS_ADD(last_ack_signal);
 
 	DEBUGFS_ADD_COUNTER(rx_packets, rx_packets);
 	DEBUGFS_ADD_COUNTER(tx_packets, tx_packets);
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 6835cea..dce7693 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -250,6 +250,7 @@ struct sta_ampdu_mlme {
  * @rx_dropped: number of dropped MPDUs from this STA
  * @last_signal: signal of last received frame from this STA
  * @avg_signal: moving average of signal of received frames from this STA
+ * @last_ack_signal: signal of last received Ack frame from this STA
  * @last_seq_ctrl: last received seq/frag number from this STA (per RX queue)
  * @tx_filtered_count: number of frames the hardware filtered for this STA
  * @tx_retry_failed: number of frames that failed retry
@@ -329,6 +330,7 @@ struct sta_info {
 	unsigned long rx_dropped;
 	int last_signal;
 	struct ewma avg_signal;
+	int last_ack_signal;
 	/* Plus 1 for non-QoS frames */
 	__le16 last_seq_ctrl[IEEE80211_NUM_TIDS + 1];
 
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index 2d931ad..6400037 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -539,6 +539,9 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 				sta->lost_packets = 0;
 			}
 		}
+
+		if (acked)
+			sta->last_ack_signal = info->status.ack_signal;
 	}
 
 	rcu_read_unlock();