ath9k: Optimize LNA check

The documentation for antenna diversity says:

"The decision of diversity is done at 802.11 preamble. So, for
11G/11B, for every MAC packet hardware will do a decision. But in
11N with aggregation, the decision is made only at the preamble and
all other MPDUs will use the same LNA as the first MPDU."

Make use of rs_firstaggr to avoid needlessly scanning for LNA
changes.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index 6ad7d6196b2e2c4a03c573b3a7fc60dd7b750dbd..6161d148cd0c7442e011080db65b1b3c3932acd2 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -1238,6 +1238,52 @@ static void ath9k_rx_skb_postprocess(struct ath_common *common,
                rxs->flag &= ~RX_FLAG_DECRYPTED;
 }
 
+/*
+ * Run the LNA combining algorithm only in these cases:
+ *
+ * Standalone WLAN cards with both LNA/Antenna diversity
+ * enabled in the EEPROM.
+ *
+ * WLAN+BT cards which are in the supported card list
+ * in ath_pci_id_table and the user has loaded the
+ * driver with "bt_ant_diversity" set to true.
+ */
+static void ath9k_antenna_check(struct ath_softc *sc,
+                               struct ath_rx_status *rs)
+{
+       struct ath_hw *ah = sc->sc_ah;
+       struct ath9k_hw_capabilities *pCap = &ah->caps;
+       struct ath_common *common = ath9k_hw_common(ah);
+
+       if (!(ah->caps.hw_caps & ATH9K_HW_CAP_ANT_DIV_COMB))
+               return;
+
+       /*
+        * All MPDUs in an aggregate will use the same LNA
+        * as the first MPDU.
+        */
+       if (rs->rs_isaggr && !rs->rs_firstaggr)
+               return;
+
+       /*
+        * Change the default rx antenna if rx diversity
+        * chooses the other antenna 3 times in a row.
+        */
+       if (sc->rx.defant != rs->rs_antenna) {
+               if (++sc->rx.rxotherant >= 3)
+                       ath_setdefantenna(sc, rs->rs_antenna);
+       } else {
+               sc->rx.rxotherant = 0;
+       }
+
+       if (pCap->hw_caps & ATH9K_HW_CAP_BT_ANT_DIV) {
+               if (common->bt_ant_diversity)
+                       ath_ant_comb_scan(sc, rs);
+       } else {
+               ath_ant_comb_scan(sc, rs);
+       }
+}
+
 static void ath9k_apply_ampdu_details(struct ath_softc *sc,
        struct ath_rx_status *rs, struct ieee80211_rx_status *rxs)
 {
@@ -1262,7 +1308,6 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush, bool hp)
        struct sk_buff *skb = NULL, *requeue_skb, *hdr_skb;
        struct ieee80211_rx_status *rxs;
        struct ath_hw *ah = sc->sc_ah;
-       struct ath9k_hw_capabilities *pCap = &ah->caps;
        struct ath_common *common = ath9k_hw_common(ah);
        struct ieee80211_hw *hw = sc->hw;
        int retval;
@@ -1398,35 +1443,7 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush, bool hp)
                        ath_rx_ps(sc, skb, rs.is_mybeacon);
                spin_unlock_irqrestore(&sc->sc_pm_lock, flags);
 
-               /*
-                * Run the LNA combining algorithm only in these cases:
-                *
-                * Standalone WLAN cards with both LNA/Antenna diversity
-                * enabled in the EEPROM.
-                *
-                * WLAN+BT cards which are in the supported card list
-                * in ath_pci_id_table and the user has loaded the
-                * driver with "bt_ant_diversity" set to true.
-                */
-               if (ah->caps.hw_caps & ATH9K_HW_CAP_ANT_DIV_COMB) {
-                       /*
-                        * Change the default rx antenna if rx diversity
-                        * chooses the other antenna 3 times in a row.
-                        */
-                       if (sc->rx.defant != rs.rs_antenna) {
-                               if (++sc->rx.rxotherant >= 3)
-                                       ath_setdefantenna(sc, rs.rs_antenna);
-                       } else {
-                               sc->rx.rxotherant = 0;
-                       }
-
-                       if (pCap->hw_caps & ATH9K_HW_CAP_BT_ANT_DIV) {
-                               if (common->bt_ant_diversity)
-                                       ath_ant_comb_scan(sc, &rs);
-                       } else {
-                               ath_ant_comb_scan(sc, &rs);
-                       }
-               }
+               ath9k_antenna_check(sc, &rs);
 
                ath9k_apply_ampdu_details(sc, &rs, rxs);