ath9k: shorten the calibration interval during strong interference

When the noise floor limits are being bypassed because of strong
interference, sensitivity is also reduced.
In order to recover from this as quickly as possible, trigger a
long periodic calibration every second instead of every 30 seconds,
until the NF median is within limits again. This is especially important
if the interference lasts for a while, since it takes multiple clean
NF calibrations to bring the median back to normal.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/ath9k.h

@@ -423,6 +423,7 @@ int ath_beaconq_config(struct ath_softc *sc);
 #define ATH_AP_SHORT_CALINTERVAL  100     /* 100 ms */
 #define ATH_ANI_POLLINTERVAL_OLD  100     /* 100 ms */
 #define ATH_ANI_POLLINTERVAL_NEW  1000    /* 1000 ms */
+#define ATH_LONG_CALINTERVAL_INT  1000    /* 1000 ms */
 #define ATH_LONG_CALINTERVAL      30000   /* 30 seconds */
 #define ATH_RESTART_CALINTERVAL   1200000 /* 20 minutes */
 

drivers/net/wireless/ath/ath9k/main.c

@@ -396,7 +396,12 @@ void ath_ani_calibrate(unsigned long data)
 	bool shortcal = false;
 	bool aniflag = false;
 	unsigned int timestamp = jiffies_to_msecs(jiffies);
-	u32 cal_interval, short_cal_interval;
+	u32 cal_interval, short_cal_interval, long_cal_interval;
+
+	if (ah->caldata && ah->caldata->nfcal_interference)
+		long_cal_interval = ATH_LONG_CALINTERVAL_INT;
+	else
+		long_cal_interval = ATH_LONG_CALINTERVAL;
 
 	short_cal_interval = (ah->opmode == NL80211_IFTYPE_AP) ?
 		ATH_AP_SHORT_CALINTERVAL : ATH_STA_SHORT_CALINTERVAL;
@@ -408,7 +413,7 @@ void ath_ani_calibrate(unsigned long data)
 	ath9k_ps_wakeup(sc);
 
 	/* Long calibration runs independently of short calibration. */
-	if ((timestamp - common->ani.longcal_timer) >= ATH_LONG_CALINTERVAL) {
+	if ((timestamp - common->ani.longcal_timer) >= long_cal_interval) {
 		longcal = true;
 		ath_print(common, ATH_DBG_ANI, "longcal @%lu\n", jiffies);
 		common->ani.longcal_timer = timestamp;