ath5k: Adaptive Noise Immunity (ANI) Implementation

This is an Adaptive Noise Imunity (ANI) implementation for ath5k. I have looked
at both ath9k and HAL sources (they are nearly the same), and even though i
have implemented some things differently, the basic algorithm is practically
the same, for now. I hope that this can serve as a clean start to improve the
algorithm later.

This also adds a possibility to manually control ANI settings, right now only
thru a debugfs file:
  * set lowest sensitivity (=highest noise immunity):
	echo sens-low > /sys/kernel/debug/ath5k/phy0/ani
  * set highest sensitivity (=lowest noise immunity):
	echo sens-high > /sys/kernel/debug/ath5k/phy0/ani
  * automatically control immunity (default):
	echo ani-on > /sys/kernel/debug/ath5k/phy0/ani
  * to see the parameters in use and watch them change:
	cat /sys/kernel/debug/ath5k/phy0/ani

Manually setting sensitivity will turn the automatic control off. You can also
control each of the five immunity parameters (noise immunity, spur immunity,
firstep, ofdm weak signal detection, cck weak signal detection) manually thru
the debugfs file.

This is tested on AR5414 and nearly doubles the thruput in a noisy 2GHz band.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath5k/base.c

@@ -58,6 +58,7 @@
 #include "base.h"
 #include "reg.h"
 #include "debug.h"
+#include "ani.h"
 
 static int modparam_nohwcrypt;
 module_param_named(nohwcrypt, modparam_nohwcrypt, bool, S_IRUGO);
@@ -363,6 +364,7 @@ static void 	ath5k_beacon_send(struct ath5k_softc *sc);
 static void 	ath5k_beacon_config(struct ath5k_softc *sc);
 static void	ath5k_beacon_update_timers(struct ath5k_softc *sc, u64 bc_tsf);
 static void	ath5k_tasklet_beacon(unsigned long data);
+static void	ath5k_tasklet_ani(unsigned long data);
 
 static inline u64 ath5k_extend_tsf(struct ath5k_hw *ah, u32 rstamp)
 {
@@ -828,6 +830,7 @@ ath5k_attach(struct pci_dev *pdev, struct ieee80211_hw *hw)
 	tasklet_init(&sc->restq, ath5k_tasklet_reset, (unsigned long)sc);
 	tasklet_init(&sc->calib, ath5k_tasklet_calibrate, (unsigned long)sc);
 	tasklet_init(&sc->beacontq, ath5k_tasklet_beacon, (unsigned long)sc);
+	tasklet_init(&sc->ani_tasklet, ath5k_tasklet_ani, (unsigned long)sc);
 
 	ret = ath5k_eeprom_read_mac(ah, mac);
 	if (ret) {
@@ -2530,7 +2533,8 @@ ath5k_init(struct ath5k_softc *sc)
 	sc->curband = &sc->sbands[sc->curchan->band];
 	sc->imask = AR5K_INT_RXOK | AR5K_INT_RXERR | AR5K_INT_RXEOL |
 		AR5K_INT_RXORN | AR5K_INT_TXDESC | AR5K_INT_TXEOL |
-		AR5K_INT_FATAL | AR5K_INT_GLOBAL;
+		AR5K_INT_FATAL | AR5K_INT_GLOBAL | AR5K_INT_MIB;
+
 	ret = ath5k_reset(sc, NULL);
 	if (ret)
 		goto done;
@@ -2642,6 +2646,7 @@ ath5k_stop_hw(struct ath5k_softc *sc)
 	tasklet_kill(&sc->restq);
 	tasklet_kill(&sc->calib);
 	tasklet_kill(&sc->beacontq);
+	tasklet_kill(&sc->ani_tasklet);
 
 	ath5k_rfkill_hw_stop(sc->ah);
 
@@ -2651,7 +2656,14 @@ ath5k_stop_hw(struct ath5k_softc *sc)
 static void
 ath5k_intr_calibration_poll(struct ath5k_hw *ah)
 {
-	if (time_is_before_eq_jiffies(ah->ah_cal_next_full)) {
+	if (time_is_before_eq_jiffies(ah->ah_cal_next_ani) &&
+	    !(ah->ah_cal_mask & AR5K_CALIBRATION_FULL)) {
+		/* run ANI only when full calibration is not active */
+		ah->ah_cal_next_ani = jiffies +
+			msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_ANI);
+		tasklet_schedule(&ah->ah_sc->ani_tasklet);
+
+	} else if (time_is_before_eq_jiffies(ah->ah_cal_next_full)) {
 		ah->ah_cal_next_full = jiffies +
 			msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_FULL);
 		tasklet_schedule(&ah->ah_sc->calib);
@@ -2710,7 +2722,9 @@ ath5k_intr(int irq, void *dev_id)
 				/* TODO */
 			}
 			if (status & AR5K_INT_MIB) {
+				sc->stats.mib_intr++;
 				ath5k_hw_update_mib_counters(ah);
+				ath5k_ani_mib_intr(ah);
 			}
 			if (status & AR5K_INT_GPIO)
 				tasklet_schedule(&sc->rf_kill.toggleq);
@@ -2775,6 +2789,18 @@ ath5k_tasklet_calibrate(unsigned long data)
 }
 
 
+static void
+ath5k_tasklet_ani(unsigned long data)
+{
+	struct ath5k_softc *sc = (void *)data;
+	struct ath5k_hw *ah = sc->ah;
+
+	ah->ah_cal_mask |= AR5K_CALIBRATION_ANI;
+	ath5k_ani_calibration(ah);
+	ah->ah_cal_mask &= ~AR5K_CALIBRATION_ANI;
+}
+
+
 /********************\
 * Mac80211 functions *
 \********************/
@@ -2874,6 +2900,8 @@ ath5k_reset(struct ath5k_softc *sc, struct ieee80211_channel *chan)
 		goto err;
 	}
 
+	ath5k_ani_init(ah, ah->ah_sc->ani_state.ani_mode);
+
 	/*
 	 * Change channels and update the h/w rate map if we're switching;
 	 * e.g. 11a to 11b/g.