ath9k: enable ANI to help with noisy environments

This enables Adaptive Noise Immunity (ANI) on ath9k.
ANI is as algorithm designed to minimize the detrimental
effects of time-varying interferences. This should
help with throughput in noisy environments. To use
ANI we re-enable the MIB interrupt. Since ANI works
on a timer and updates the noise floor we take
advantage of this and also report a non-static noise
floor now to mac80211.

Signed-off-by: Sujith Manoharan <Sujith.Manoharan@atheros.com>
Signed-off-by: Jouni Malinen <Jouni.Malinen@Atheros.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/drivers/net/wireless/ath9k/main.c b/drivers/net/wireless/ath9k/main.c
index 2caba4403167..74726990d59e 100644
--- a/drivers/net/wireless/ath9k/main.c
+++ b/drivers/net/wireless/ath9k/main.c
@@ -274,10 +274,12 @@ static void ath9k_rx_prepare(struct ath_softc *sc,
         rx_status->mactime = status->tsf;
         rx_status->band = curchan->band;
         rx_status->freq =  curchan->center_freq;
-        rx_status->noise = ATH_DEFAULT_NOISE_FLOOR;
+        rx_status->noise = sc->sc_ani.sc_noise_floor;
         rx_status->signal = rx_status->noise + status->rssi;
         rx_status->rate_idx = ath_rate2idx(sc, (status->rateKbps / 100));
         rx_status->antenna = status->antenna;
+
+        /* XXX Fix me, 64 cannot be the max rssi value, rigure it out */
         rx_status->qual = status->rssi * 100 / 64;
 
         if (status->flags & ATH_RX_MIC_ERROR)
@@ -427,6 +429,11 @@ static void ath9k_bss_assoc_info(struct ath_softc *sc,
                 ath_rate_newstate(sc, avp);
                 /* Update ratectrl about the new state */
                 ath_rc_node_update(hw, avp->rc_node);
+
+                /* Start ANI */
+                mod_timer(&sc->sc_ani.timer,
+                        jiffies + msecs_to_jiffies(ATH_ANI_POLLINTERVAL));
+
         } else {
                 DPRINTF(sc, ATH_DBG_CONFIG,
                 "%s: Bss Info DISSOC\n", __func__);
@@ -1173,6 +1180,13 @@ static int ath9k_add_interface(struct ieee80211_hw *hw,
                 return error;
         }
 
+        if (conf->type == NL80211_IFTYPE_AP) {
+                /* TODO: is this a suitable place to start ANI for AP mode? */
+                /* Start ANI */
+                mod_timer(&sc->sc_ani.timer,
+                          jiffies + msecs_to_jiffies(ATH_ANI_POLLINTERVAL));
+        }
+
         return 0;
 }
 
@@ -1195,6 +1209,8 @@ static void ath9k_remove_interface(struct ieee80211_hw *hw,
 #ifdef CONFIG_SLOW_ANT_DIV
         ath_slow_ant_div_stop(&sc->sc_antdiv);
 #endif
+        /* Stop ANI */
+        del_timer_sync(&sc->sc_ani.timer);
 
         /* Update ratectrl */
         ath_rate_newstate(sc, avp);