ath9k: Handle abnormal NAV in AP mode

Beacon transmission would get stuck if the NAV is
an invalid value for some reason. Check and correct
the NAV value in the HW when this happens.

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

3 files changed, 16 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath9k/beacon.c b/drivers/net/wireless/ath/ath9k/beacon.c
index b5c16b3a37b9..17be35392bb4 100644
--- a/drivers/net/wireless/ath/ath9k/beacon.c
+++ b/drivers/net/wireless/ath/ath9k/beacon.c
@@ -334,6 +334,8 @@ void ath9k_beacon_tasklet(unsigned long data)
         if (ath9k_hw_numtxpending(ah, sc->beacon.beaconq) != 0) {
                 sc->beacon.bmisscnt++;
 
+                ath9k_hw_check_nav(ah);
+
                 if (!ath9k_hw_check_alive(ah))
                         ieee80211_queue_work(sc->hw, &sc->hw_check_work);
 
diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 525ac984eafd..d3206ab40297 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -1656,6 +1656,19 @@ hang_check_iter:
         return true;
 }
 
+void ath9k_hw_check_nav(struct ath_hw *ah)
+{
+        struct ath_common *common = ath9k_hw_common(ah);
+        u32 val;
+
+        val = REG_READ(ah, AR_NAV);
+        if (val != 0xdeadbeef && val > 0x7fff) {
+                ath_dbg(common, BSTUCK, "Abnormal NAV: 0x%x\n", val);
+                REG_WRITE(ah, AR_NAV, 0);
+        }
+}
+EXPORT_SYMBOL(ath9k_hw_check_nav);
+
 bool ath9k_hw_check_alive(struct ath_hw *ah)
 {
         int count = 50;
diff --git a/drivers/net/wireless/ath/ath9k/hw.h b/drivers/net/wireless/ath/ath9k/hw.h
index 5e564c788813..5376011d5200 100644
--- a/drivers/net/wireless/ath/ath9k/hw.h
+++ b/drivers/net/wireless/ath/ath9k/hw.h
@@ -1031,6 +1031,7 @@ void ath9k_hw_set11nmac2040(struct ath_hw *ah);
 void ath9k_hw_beaconinit(struct ath_hw *ah, u32 next_beacon, u32 beacon_period);
 void ath9k_hw_set_sta_beacon_timers(struct ath_hw *ah,
                                     const struct ath9k_beacon_state *bs);
+void ath9k_hw_check_nav(struct ath_hw *ah);
 bool ath9k_hw_check_alive(struct ath_hw *ah);
 
 bool ath9k_hw_setpower(struct ath_hw *ah, enum ath9k_power_mode mode);