ath5k: keep beacon RSSI average
Keep an exponentially weighted moving average of the beacon RSSI in our BSS.
It will be used by the ANI implementation.
The averaging algorithm is copied from rt2x00, Thanks :)
Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath5k/ath5k.h b/drivers/net/wireless/ath/ath5k/ath5k.h
index 6334294..cefd28d 100644
--- a/drivers/net/wireless/ath/ath5k/ath5k.h
+++ b/drivers/net/wireless/ath/ath5k/ath5k.h
@@ -992,6 +992,15 @@
s16 nfval[ATH5K_NF_CAL_HIST_MAX]; /* last few noise floors */
};
+/**
+ * struct avg_val - Helper structure for average calculation
+ * @avg: contains the actual average value
+ * @avg_weight: is used internally during calculation to prevent rounding errors
+ */
+struct ath5k_avg_val {
+ int avg;
+ int avg_weight;
+};
/***************************************\
HARDWARE ABSTRACTION LAYER STRUCTURE
@@ -1096,6 +1105,9 @@
struct ath5k_nfcal_hist ah_nfcal_hist;
+ /* average beacon RSSI in our BSS (used by ANI) */
+ struct ath5k_avg_val ah_beacon_rssi_avg;
+
/* noise floor from last periodic calibration */
s32 ah_noise_floor;
@@ -1305,4 +1317,27 @@
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