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>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 11eab9f01fd8..303ce27964c1 100644
--- 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;