ath9k: reduce false positives in the baseband hang check

SVN-Revision: 25359

package/mac80211/patches/570-ath9k_bb_hang_check_fix.patch

@@ -0,0 +1,109 @@
+--- a/drivers/net/wireless/ath/ath9k/main.c
++++ b/drivers/net/wireless/ath/ath9k/main.c
+@@ -177,7 +177,12 @@ static void ath_update_survey_nf(struct 
+ 	}
+ }
+ 
+-static void ath_update_survey_stats(struct ath_softc *sc)
++/*
++ * Updates the survey statistics and returns the busy time since last
++ * update in %, if the measurement duration was long enough for the
++ * result to be useful, -1 otherwise.
++ */
++static int ath_update_survey_stats(struct ath_softc *sc)
+ {
+ 	struct ath_hw *ah = sc->sc_ah;
+ 	struct ath_common *common = ath9k_hw_common(ah);
+@@ -185,9 +190,10 @@ static void ath_update_survey_stats(stru
+ 	struct survey_info *survey = &sc->survey[pos];
+ 	struct ath_cycle_counters *cc = &common->cc_survey;
+ 	unsigned int div = common->clockrate * 1000;
++	int ret = 0;
+ 
+ 	if (!ah->curchan)
+-		return;
++		return -1;
+ 
+ 	if (ah->power_mode == ATH9K_PM_AWAKE)
+ 		ath_hw_cycle_counters_update(common);
+@@ -202,9 +208,18 @@ static void ath_update_survey_stats(stru
+ 		survey->channel_time_rx += cc->rx_frame / div;
+ 		survey->channel_time_tx += cc->tx_frame / div;
+ 	}
++
++	if (cc->cycles < div)
++		return -1;
++
++	if (cc->cycles > 0)
++		ret = cc->rx_busy * 100 / cc->cycles;
++
+ 	memset(cc, 0, sizeof(*cc));
+ 
+ 	ath_update_survey_nf(sc, pos);
++
++	return ret;
+ }
+ 
+ /*
+@@ -226,6 +241,8 @@ int ath_set_channel(struct ath_softc *sc
+ 	if (sc->sc_flags & SC_OP_INVALID)
+ 		return -EIO;
+ 
++	sc->hw_busy_count = 0;
++
+ 	del_timer_sync(&common->ani.timer);
+ 	cancel_work_sync(&sc->paprd_work);
+ 	cancel_work_sync(&sc->hw_check_work);
+@@ -584,17 +601,25 @@ static void ath_node_detach(struct ath_s
+ void ath_hw_check(struct work_struct *work)
+ {
+ 	struct ath_softc *sc = container_of(work, struct ath_softc, hw_check_work);
+-	int i;
++	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
++	unsigned long flags;
++	int busy;
+ 
+ 	ath9k_ps_wakeup(sc);
++	if (ath9k_hw_check_alive(sc->sc_ah))
++		goto out;
+ 
+-	for (i = 0; i < 3; i++) {
+-		if (ath9k_hw_check_alive(sc->sc_ah))
+-			goto out;
++	spin_lock_irqsave(&common->cc_lock, flags);
++	busy = ath_update_survey_stats(sc);
++	spin_unlock_irqrestore(&common->cc_lock, flags);
+ 
+-		msleep(1);
+-	}
+-	ath_reset(sc, true);
++	ath_dbg(common, ATH_DBG_RESET, "Possible baseband hang, "
++		"busy=%d (try %d)\n", busy, sc->hw_busy_count + 1);
++	if (busy >= 99) {
++		if (++sc->hw_busy_count >= 3)
++			ath_reset(sc, true);
++	} else if (busy >= 0)
++		sc->hw_busy_count = 0;
+ 
+ out:
+ 	ath9k_ps_restore(sc);
+@@ -988,6 +1013,8 @@ int ath_reset(struct ath_softc *sc, bool
+ 	struct ieee80211_hw *hw = sc->hw;
+ 	int r;
+ 
++	sc->hw_busy_count = 0;
++
+ 	/* Stop ANI */
+ 	del_timer_sync(&common->ani.timer);
+ 
+--- a/drivers/net/wireless/ath/ath9k/ath9k.h
++++ b/drivers/net/wireless/ath/ath9k/ath9k.h
+@@ -598,6 +598,8 @@ struct ath_softc {
+ 	struct completion paprd_complete;
+ 	bool paprd_pending;
+ 
++	unsigned int hw_busy_count;
++
+ 	u32 intrstatus;
+ 	u32 sc_flags; /* SC_OP_* */
+ 	u16 ps_flags; /* PS_* */