ath9k: improve stuck beacon recovery and noise floor handling. significantly improves stability under strong interference in ap mode

SVN-Revision: 22460

1 files changed, 127 insertions, 0 deletions

diff --git a/package/mac80211/patches/542-ath9k_bstuck_nf_calibrate.patch b/package/mac80211/patches/542-ath9k_bstuck_nf_calibrate.patch
new file mode 100644
index 0000000..35db2cb
--- /dev/null
+++ b/package/mac80211/patches/542-ath9k_bstuck_nf_calibrate.patch
@@ -0,0 +1,127 @@
+--- 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 da
+ 			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");
+--- 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(struc
+ 
+ 
+ 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_b
+ 				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, s
+ 
+ 	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 +407,26 @@ s16 ath9k_hw_getchan_noise(struct ath_hw
+ 	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);
++
++	caldata->nfcal_interference = true;
++}
++EXPORT_SYMBOL(ath9k_hw_bstuck_nfcal);
++
+--- 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, 
+ 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);
+--- 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];