4 files changed, 65 insertions, 4 deletions

diff --git a/drivers/net/wireless/ath/ath9k/beacon.c b/drivers/net/wireless/ath/ath9k/beacon.c
index 102f1234f794..081192e78a46 100644
--- a/drivers/net/wireless/ath/ath9k/beacon.c
+++ b/drivers/net/wireless/ath/ath9k/beacon.c
@@ -362,6 +362,7 @@ void ath_beacon_tasklet(unsigned long data)
                         ath_print(common, ATH_DBG_BSTUCK,
                                   "missed %u consecutive beacons\n",
                                   sc->beacon.bmisscnt);
+                        ath9k_hw_bstuck_nfcal(ah);
                 } else if (sc->beacon.bmisscnt >= BSTUCK_THRESH) {
                         ath_print(common, ATH_DBG_BSTUCK,
                                   "beacon is officially stuck\n");
diff --git a/drivers/net/wireless/ath/ath9k/calib.c b/drivers/net/wireless/ath/ath9k/calib.c
index ccb1b2eae85e..67ee5d735cc1 100644
--- a/drivers/net/wireless/ath/ath9k/calib.c
+++ b/drivers/net/wireless/ath/ath9k/calib.c
@@ -65,12 +65,16 @@ static s16 ath9k_hw_get_default_nf(struct ath_hw *ah,
 
 
 static void ath9k_hw_update_nfcal_hist_buffer(struct ath_hw *ah,
-                                              struct ath9k_nfcal_hist *h,
+                                              struct ath9k_hw_cal_data *cal,
                                               int16_t *nfarray)
 {
+        struct ath_common *common = ath9k_hw_common(ah);
         struct ath_nf_limits *limit;
+        struct ath9k_nfcal_hist *h;
+        bool high_nf_mid = false;
         int i;
 
+        h = cal->nfCalHist;
         limit = ath9k_hw_get_nf_limits(ah, ah->curchan);
 
         for (i = 0; i < NUM_NF_READINGS; i++) {
@@ -87,9 +91,38 @@ static void ath9k_hw_update_nfcal_hist_buffer(struct ath_hw *ah,
                                 ath9k_hw_get_nf_hist_mid(h[i].nfCalBuffer);
                 }
 
-                if (h[i].privNF > limit->max)
-                        h[i].privNF = limit->max;
+                if (!h[i].privNF)
+                        continue;
+
+                if (h[i].privNF > limit->max) {
+                        high_nf_mid = true;
+
+                        ath_print(common, ATH_DBG_CALIBRATE,
+                                  "NFmid[%d] (%d) > MAX (%d), %s\n",
+                                  i, h[i].privNF, limit->max,
+                                  (cal->nfcal_interference ?
+                                   "not corrected (due to interference)" :
+                                   "correcting to MAX"));
+
+                        /*
+                         * Normally we limit the average noise floor by the
+                         * hardware specific maximum here. However if we have
+                         * encountered stuck beacons because of interference,
+                         * we bypass this limit here in order to better deal
+                         * with our environment.
+                         */
+                        if (!cal->nfcal_interference)
+                                h[i].privNF = limit->max;
+                }
         }
+
+        /*
+         * If the noise floor seems normal for all chains, assume that
+         * there is no significant interference in the environment anymore.
+         * Re-enable the enforcement of the NF maximum again.
+         */
+        if (!high_nf_mid)
+                cal->nfcal_interference = false;
 }
 
 static bool ath9k_hw_get_nf_thresh(struct ath_hw *ah,
@@ -339,7 +372,7 @@ bool ath9k_hw_getnf(struct ath_hw *ah, struct ath9k_channel *chan)
 
         h = caldata->nfCalHist;
         caldata->nfcal_pending = false;
-        ath9k_hw_update_nfcal_hist_buffer(ah, h, nfarray);
+        ath9k_hw_update_nfcal_hist_buffer(ah, caldata, nfarray);
         caldata->rawNoiseFloor = h[0].privNF;
         return true;
 }
@@ -374,3 +407,28 @@ s16 ath9k_hw_getchan_noise(struct ath_hw *ah, struct ath9k_channel *chan)
         return ah->caldata->rawNoiseFloor;
 }
 EXPORT_SYMBOL(ath9k_hw_getchan_noise);
+
+void ath9k_hw_bstuck_nfcal(struct ath_hw *ah)
+{
+        struct ath9k_hw_cal_data *caldata = ah->caldata;
+
+        if (unlikely(!caldata))
+                return;
+
+        /*
+         * If beacons are stuck, the most likely cause is interference.
+         * Triggering a noise floor calibration at this point helps the
+         * hardware adapt to a noisy environment much faster.
+         * To ensure that we recover from stuck beacons quickly, let
+         * the baseband update the internal NF value itself, similar to
+         * what is being done after a full reset.
+         */
+        if (!caldata->nfcal_pending)
+                ath9k_hw_start_nfcal(ah, true);
+        else if (!(REG_READ(ah, AR_PHY_AGC_CONTROL) & AR_PHY_AGC_CONTROL_NF))
+                ath9k_hw_getnf(ah, ah->curchan);
+
+        caldata->nfcal_interference = true;
+}
+EXPORT_SYMBOL(ath9k_hw_bstuck_nfcal);
+
diff --git a/drivers/net/wireless/ath/ath9k/calib.h b/drivers/net/wireless/ath/ath9k/calib.h
index 0a304b3eeeb6..5b053a6260b2 100644
--- a/drivers/net/wireless/ath/ath9k/calib.h
+++ b/drivers/net/wireless/ath/ath9k/calib.h
@@ -113,6 +113,7 @@ void ath9k_hw_loadnf(struct ath_hw *ah, struct ath9k_channel *chan);
 bool ath9k_hw_getnf(struct ath_hw *ah, struct ath9k_channel *chan);
 void ath9k_init_nfcal_hist_buffer(struct ath_hw *ah,
                                   struct ath9k_channel *chan);
+void ath9k_hw_bstuck_nfcal(struct ath_hw *ah);
 s16 ath9k_hw_getchan_noise(struct ath_hw *ah, struct ath9k_channel *chan);
 void ath9k_hw_reset_calibration(struct ath_hw *ah,
                                 struct ath9k_cal_list *currCal);
diff --git a/drivers/net/wireless/ath/ath9k/hw.h b/drivers/net/wireless/ath/ath9k/hw.h
index 399f7c1283cd..1601dd439890 100644
--- a/drivers/net/wireless/ath/ath9k/hw.h
+++ b/drivers/net/wireless/ath/ath9k/hw.h
@@ -355,6 +355,7 @@ struct ath9k_hw_cal_data {
         int16_t rawNoiseFloor;
         bool paprd_done;
         bool nfcal_pending;
+        bool nfcal_interference;
         u16 small_signal_gain[AR9300_MAX_CHAINS];
         u32 pa_table[AR9300_MAX_CHAINS][PAPRD_TABLE_SZ];
         struct ath9k_nfcal_hist nfCalHist[NUM_NF_READINGS];