ath9k: reduce baseband hang detection false positive rate

Check if the baseband state remains stable, and add a small delay
between register reads.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 11eab9f01fd89ac9bb8f9b665646051a6386ac0a..303ce27964c14c3469d245632c6f5739289520b0 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -1534,7 +1534,7 @@ EXPORT_SYMBOL(ath9k_hw_check_nav);
 bool ath9k_hw_check_alive(struct ath_hw *ah)
 {
        int count = 50;
-       u32 reg;
+       u32 reg, last_val;
 
        if (AR_SREV_9300(ah))
                return !ath9k_hw_detect_mac_hang(ah);
@@ -1542,9 +1542,13 @@ bool ath9k_hw_check_alive(struct ath_hw *ah)
        if (AR_SREV_9285_12_OR_LATER(ah))
                return true;
 
+       last_val = REG_READ(ah, AR_OBS_BUS_1);
        do {
                reg = REG_READ(ah, AR_OBS_BUS_1);
+               if (reg != last_val)
+                       return true;
 
+               last_val = reg;
                if ((reg & 0x7E7FFFEF) == 0x00702400)
                        continue;
 
@@ -1556,6 +1560,8 @@ bool ath9k_hw_check_alive(struct ath_hw *ah)
                default:
                        return true;
                }
+
+               udelay(1);
        } while (count-- > 0);
 
        return false;