[PATCH ath-current 1/2] wifi: ath9k_htc: do not start ANI before the first channel is set

[Mehmet Fide <mehmet.fide@gmail.com>]

From: Mehmet Fide <mehmet.fide@screeningeagle.com>

ath9k_htc_add_interface() starts ANI for the first AP interface, before
any channel is configured. The per-channel calibration data only gets
attached by the first ath9k_htc_set_channel() that is not a fast
channel change, and that same call cancels the ANI work a few
milliseconds after add_interface, so normally the work never runs.

When the bring-up stalls for more than the 100 ms ANI poll interval in
between, it does run, and ar9002_hw_per_calibration() records the IQ
calibration result in the calibration data that does not exist yet:

  Unable to handle kernel NULL pointer dereference at virtual address
  00000008
  PC is at ar9002_hw_calibrate+0x1f8/0x570 [ath9k_hw]
  Workqueue: phy0 ath9k_htc_ani_work [ath9k_htc]

Seen about once per thousand AP starts with an AR9271 on a Cortex-A5
board that starts hostapd while still booting; a 500 ms delay after
add_interface reproduces it on every start. The crashed work never
completes, so the next cancel_delayed_work_sync() blocks for good.

Drop the start; it has nothing to calibrate against and is cancelled
anyway. The TSF adjust bit that shared its condition is now set for
every AP interface, which is harmless: the next reset applies it. The
next patch starts ANI once the interface beacons.

Fixes: a236254c35f0 ("ath9k_htc: Add ANI for AP mode")
Cc: stable@vger.kernel.org
Signed-off-by: Mehmet Fide <mehmet.fide@screeningeagle.com>
---
 drivers/net/wireless/ath/ath9k/htc_drv_main.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_main.c b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
index 0d6272ac0dac..a86dd28b0ab7 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_main.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
@@ -1098,11 +1098,8 @@ static int ath9k_htc_add_interface(struct ieee80211_hw *hw,
 
 	ath9k_htc_set_opmode(priv);
 
-	if ((priv->ah->opmode == NL80211_IFTYPE_AP) &&
-	    !test_bit(ATH_OP_ANI_RUN, &common->op_flags)) {
+	if (priv->ah->opmode == NL80211_IFTYPE_AP)
 		ath9k_hw_set_tsfadjust(priv->ah, true);
-		ath9k_htc_start_ani(priv);
-	}
 
 	ath_dbg(common, CONFIG, "Attach a VIF of type: %d at idx: %d\n",
 		vif->type, avp->index);
-- 
2.55.0