package/kernel/mac80211/patches/315-ath9k_hw-check-if-the-chip-failed-to-wake-up.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Wed, 25 Jan 2017 12:58:17 +0100
   3 Subject: [PATCH] ath9k_hw: check if the chip failed to wake up
   4
   5 In an RFC patch, Sven Eckelmann and Simon Wunderlich reported:
   6
   7 "QCA 802.11n chips (especially AR9330/AR9340) sometimes end up in a
   8 state in which a read of AR_CFG always returns 0xdeadbeef.
   9 This should not happen when when the power_mode of the device is
  10 ATH9K_PM_AWAKE."
  11
  12 Include the check for the default register state in the existing MAC
  13 hang check.
  14
  15 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  16 ---
  17
  18 --- a/drivers/net/wireless/ath/ath9k/hw.c
  19 +++ b/drivers/net/wireless/ath/ath9k/hw.c
  20 @@ -1624,6 +1624,10 @@ bool ath9k_hw_check_alive(struct ath_hw
  21         int count = 50;
  22         u32 reg, last_val;
  23
  24 +       /* Check if chip failed to wake up */
  25 +       if (REG_READ(ah, AR_CFG) == 0xdeadbeef)
  26 +               return false;
  27 +
  28         if (AR_SREV_9300(ah))
  29                 return !ath9k_hw_detect_mac_hang(ah);
  30