ath5k: Use generic EWMA library

Remove ath5k's private moving average implementation in favour of the generic
library version.

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

drivers/net/wireless/ath/ath5k/Kconfig

@@ -4,6 +4,7 @@ config ATH5K
 	select MAC80211_LEDS
 	select LEDS_CLASS
 	select NEW_LEDS
+	select AVERAGE
 	---help---
 	  This module adds support for wireless adapters based on
 	  Atheros 5xxx chipset.

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

@@ -216,7 +216,7 @@ static void
 ath5k_ani_raise_immunity(struct ath5k_hw *ah, struct ath5k_ani_state *as,
 			 bool ofdm_trigger)
 {
-	int rssi = ah->ah_beacon_rssi_avg.avg;
+	int rssi = ewma_read(&ah->ah_beacon_rssi_avg);
 
 	ATH5K_DBG_UNLIMIT(ah->ah_sc, ATH5K_DEBUG_ANI, "raise immunity (%s)",
 		ofdm_trigger ? "ODFM" : "CCK");
@@ -301,7 +301,7 @@ ath5k_ani_raise_immunity(struct ath5k_hw *ah, struct ath5k_ani_state *as,
 static void
 ath5k_ani_lower_immunity(struct ath5k_hw *ah, struct ath5k_ani_state *as)
 {
-	int rssi = ah->ah_beacon_rssi_avg.avg;
+	int rssi = ewma_read(&ah->ah_beacon_rssi_avg);
 
 	ATH5K_DBG_UNLIMIT(ah->ah_sc, ATH5K_DEBUG_ANI, "lower immunity");
 

drivers/net/wireless/ath/ath5k/ath5k.h

@@ -25,6 +25,7 @@
 
 #include <linux/io.h>
 #include <linux/types.h>
+#include <linux/average.h>
 #include <net/mac80211.h>
 
 /* RX/TX descriptor hw structs
@@ -1102,7 +1103,7 @@ struct ath5k_hw {
 	struct ath5k_nfcal_hist ah_nfcal_hist;
 
 	/* average beacon RSSI in our BSS (used by ANI) */
-	struct ath5k_avg_val	ah_beacon_rssi_avg;
+	struct ewma		ah_beacon_rssi_avg;
 
 	/* noise floor from last periodic calibration */
 	s32			ah_noise_floor;
@@ -1315,27 +1316,4 @@ static inline u32 ath5k_hw_bitswap(u32 val, unsigned int bits)
 	return retval;
 }
 
-#define AVG_SAMPLES	8
-#define AVG_FACTOR	1000
-
-/**
- * ath5k_moving_average -  Exponentially weighted moving average
- * @avg: average structure
- * @val: current value
- *
- * This implementation make use of a struct ath5k_avg_val to prevent rounding
- * errors.
- */
-static inline struct ath5k_avg_val
-ath5k_moving_average(const struct ath5k_avg_val avg, const int val)
-{
-	struct ath5k_avg_val new;
-	new.avg_weight = avg.avg_weight  ?
-		(((avg.avg_weight * ((AVG_SAMPLES) - 1)) +
-			(val * (AVG_FACTOR))) / (AVG_SAMPLES)) :
-		(val * (AVG_FACTOR));
-	new.avg = new.avg_weight / (AVG_FACTOR);
-	return new;
-}
-
 #endif

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

@@ -1301,8 +1301,7 @@ ath5k_update_beacon_rssi(struct ath5k_softc *sc, struct sk_buff *skb, int rssi)
 	    memcmp(mgmt->bssid, common->curbssid, ETH_ALEN) != 0)
 		return;
 
-	ah->ah_beacon_rssi_avg = ath5k_moving_average(ah->ah_beacon_rssi_avg,
+	ewma_add(&ah->ah_beacon_rssi_avg, rssi);
-						      rssi);
 
 	/* in IBSS mode we should keep RSSI statistics per neighbour */
 	/* le16_to_cpu(mgmt->u.beacon.capab_info) & WLAN_CAPABILITY_IBSS */
@@ -2556,6 +2555,7 @@ ath5k_reset(struct ath5k_softc *sc, struct ieee80211_channel *chan)
 	ah->ah_cal_next_full = jiffies;
 	ah->ah_cal_next_ani = jiffies;
 	ah->ah_cal_next_nf = jiffies;
+	ewma_init(&ah->ah_beacon_rssi_avg, 1000, 8);
 
 	/*
 	 * Change channels and update the h/w rate map if we're switching;

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

@@ -719,7 +719,7 @@ static ssize_t read_file_ani(struct file *file, char __user *user_buf,
 			st->mib_intr);
 	len += snprintf(buf+len, sizeof(buf)-len,
 			"beacon RSSI average:\t%d\n",
-			sc->ah->ah_beacon_rssi_avg.avg);
+			(int)ewma_read(&sc->ah->ah_beacon_rssi_avg));
 
 #define CC_PRINT(_struct, _field) \
 	_struct._field, \