From: Felix Fietkau <nbd@nbd.name>
Date: Thu, 2 Feb 2017 09:14:51 +0000 (+0100)
Subject: ath9k_hw: check if the chip failed to wake up
X-Git-Tag: v4.1.52~77
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=858463ce794f5ae28c23cd43ab91db021b1adaf2;p=users%2Fdwmw2%2Flinux.git

ath9k_hw: check if the chip failed to wake up

[ Upstream commit a34d0a0da1abae46a5f6ebd06fb0ec484ca099d9 ]

In an RFC patch, Sven Eckelmann and Simon Wunderlich reported:

"QCA 802.11n chips (especially AR9330/AR9340) sometimes end up in a
state in which a read of AR_CFG always returns 0xdeadbeef.
This should not happen when when the power_mode of the device is
ATH9K_PM_AWAKE."

Include the check for the default register state in the existing MAC
hang check.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---

diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 5e15e8e10ed39..bb64d7377a968 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -1593,6 +1593,10 @@ bool ath9k_hw_check_alive(struct ath_hw *ah)
 	int count = 50;
 	u32 reg, last_val;
 
+	/* Check if chip failed to wake up */
+	if (REG_READ(ah, AR_CFG) == 0xdeadbeef)
+		return false;
+
 	if (AR_SREV_9300(ah))
 		return !ath9k_hw_detect_mac_hang(ah);