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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>
This commit is contained in:
Bruno Randolf 2010-03-25 14:49:25 +09:00 committed by John W. Linville
parent 6a8a3f6b2a
commit b4ea449df9
2 changed files with 56 additions and 0 deletions
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35
drivers/net/wireless/ath/ath5k/ath5k.h
View File

@ -992,6 +992,15 @@ struct ath5k_nfcal_hist
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_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;
/* noise floor from last periodic calibration */
s32 ah_noise_floor;
@ -1305,4 +1317,27 @@ 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

21
drivers/net/wireless/ath/ath5k/base.c
View File

@ -1803,6 +1803,25 @@ ath5k_check_ibss_tsf(struct ath5k_softc *sc, struct sk_buff *skb,
}
}
static void
ath5k_update_beacon_rssi(struct ath5k_softc *sc, struct sk_buff *skb, int rssi)
{
struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *)skb->data;
struct ath5k_hw *ah = sc->ah;
struct ath_common *common = ath5k_hw_common(ah);
/* only beacons from our BSSID */
if (!ieee80211_is_beacon(mgmt->frame_control) ||
memcmp(mgmt->bssid, common->curbssid, ETH_ALEN) != 0)
return;
ah->ah_beacon_rssi_avg = ath5k_moving_average(ah->ah_beacon_rssi_avg,
rssi);
/* in IBSS mode we should keep RSSI statistics per neighbour */
/* le16_to_cpu(mgmt->u.beacon.capab_info) & WLAN_CAPABILITY_IBSS */
}
/*
* Compute padding position. skb must contains an IEEE 802.11 frame
*/
@ -2022,6 +2041,8 @@ ath5k_tasklet_rx(unsigned long data)
ath5k_debug_dump_skb(sc, skb, "RX ", 0);
ath5k_update_beacon_rssi(sc, skb, rs.rs_rssi);
/* check beacons in IBSS mode */
if (sc->opmode == NL80211_IFTYPE_ADHOC)
ath5k_check_ibss_tsf(sc, skb, rxs);