From: Felix Fietkau <nbd@openwrt.org>
Date: Mon, 24 Feb 2014 21:26:05 +0000 (+0100)
Subject: ath9k: reduce baseband hang detection false positive rate
X-Git-Tag: accepted/tizen/common/20141203.182822~411^2~21^2^2~13
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d31a36a6d87f68c3b97193bfca11e99d0cc385f7;p=platform%2Fkernel%2Flinux-arm64.git

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 11eab9f..303ce27 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;