Subject: [PATCH] (revised) improved statistics for bcm43xx-softmac

From: Larry Finger <[email-masked]>
Date: Thu, 29 Jun 2006 22:48:59 -0500

This patch improves the statistics returned from bcm43xx_get_wireless_stats. The signal level comes
from smoothing the "rssi" value returned by the firmware after it is converted into a dBm value by 
the driver. The quality value is a hack derived from the smoothed level and an assumed RX_POWER_MAX 
of -10 dBM. The noise value is still the one calculated from the clean-room formula. On my system, 
this is roughly -65 dBm, which seems too high.

The revised version uses the ieee80211 spinlock to protect traversing of the network list.

Signed-Off-By: Larry Finger <[email-masked]>

=======================================================

diff --git a/drivers/net/wireless/bcm43xx/bcm43xx_main.c b/drivers/net/wireless/bcm43xx/bcm43xx_main.c
index 1cd47c5..4c55c2c 100644
--- a/drivers/net/wireless/bcm43xx/bcm43xx_main.c
+++ b/drivers/net/wireless/bcm43xx/bcm43xx_main.c
@@ -1581,17 +1581,9 @@ static void handle_irq_noise(struct bcm4
  		else
  			average -= 48;

-/* FIXME: This is wrong, but people want fancy stats. well... */
-bcm->stats.noise = average;
-		if (average > -65)
-			bcm->stats.link_quality = 0;
-		else if (average > -75)
-			bcm->stats.link_quality = 1;
-		else if (average > -85)
-			bcm->stats.link_quality = 2;
-		else
-			bcm->stats.link_quality = 3;
-//		dprintk(KERN_INFO PFX "Link Quality: %u (avg was %d)\n", bcm->stats.link_quality, average);
+/* FIXME: This matches the formula from http://bcm-specs.sipsolutions.net/LinkQuality,
+          but yields a value that is probably too large. */
+		bcm->stats.noise = average;
  drop_calculation:
  		bcm->noisecalc.calculation_running = 0;
  		return;
diff --git a/drivers/net/wireless/bcm43xx/bcm43xx_wx.c b/drivers/net/wireless/bcm43xx/bcm43xx_wx.c
index 5c36e29..66bfeee 100644
--- a/drivers/net/wireless/bcm43xx/bcm43xx_wx.c
+++ b/drivers/net/wireless/bcm43xx/bcm43xx_wx.c
@@ -47,6 +47,8 @@ #include "bcm43xx_phy.h"
  #define BCM43xx_WX_VERSION	18

  #define MAX_WX_STRING		80
+/* FIXME: the next line is a guess as to what the maximum value of RX power (in dBm) might be */
+#define RX_POWER_MAX		-10

  static int bcm43xx_wx_get_name(struct net_device *net_dev,
@@ -227,15 +229,15 @@ static int bcm43xx_wx_get_rangeparams(st

  	range->max_qual.qual = 100;
  	/* TODO: Real max RSSI */
-	range->max_qual.level = 3;
-	range->max_qual.noise = 100;
-	range->max_qual.updated = 7;
-
-	range->avg_qual.qual = 70;
-	range->avg_qual.level = 2;
-	range->avg_qual.noise = 40;
-	range->avg_qual.updated = 7;
-
+	range->max_qual.level = 0;
+	range->max_qual.noise = 0;
+	range->max_qual.updated = IW_QUAL_ALL_UPDATED;
+
+	range->avg_qual.qual = 50;
+	range->avg_qual.level = 0;
+	range->avg_qual.noise = 0;
+	range->avg_qual.updated = IW_QUAL_ALL_UPDATED;
+
  	range->min_rts = BCM43xx_MIN_RTS_THRESHOLD;
  	range->max_rts = BCM43xx_MAX_RTS_THRESHOLD;
  	range->min_frag = MIN_FRAG_THRESHOLD;
@@ -827,6 +829,9 @@ static struct iw_statistics *bcm43xx_get
  	struct bcm43xx_private *bcm = bcm43xx_priv(net_dev);
  	struct ieee80211softmac_device *mac = ieee80211_priv(net_dev);
  	struct iw_statistics *wstats;
+	struct ieee80211_network *network = NULL;
+	static int tmp_level = 0;
+	unsigned long flags;

  	wstats = &bcm->stats.wstats;
  	if (!mac->associated) {
@@ -844,16 +849,25 @@ static struct iw_statistics *bcm43xx_get
  		wstats->qual.level = 0;
  		wstats->qual.noise = 0;
  		wstats->qual.updated = 7;
-		wstats->qual.updated |= IW_QUAL_NOISE_INVALID |
-			IW_QUAL_QUAL_INVALID | IW_QUAL_LEVEL_INVALID;
+		wstats->qual.updated |= IW_QUAL_ALL_UPDATED;
  		return wstats;
  	}
  	/* fill in the real statistics when iface associated */
-	wstats->qual.qual = 100;     // TODO: get the real signal quality
-	wstats->qual.level = 3 - bcm->stats.link_quality;
+	spin_lock_irqsave(&mac->ieee->lock, flags);
+	list_for_each_entry(network, &mac->ieee->network_list, list) {
+		if (!memcmp(mac->associnfo.bssid, network->bssid, ETH_ALEN)) {
+			if (!tmp_level)		/* get initial value */
+				tmp_level = network->stats.rssi;
+			else			/* smooth results */
+				tmp_level = (7 * tmp_level + network->stats.rssi)/8;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&mac->ieee->lock, flags);
+	wstats->qual.level = tmp_level;
+	wstats->qual.qual = 100 + tmp_level - RX_POWER_MAX; // TODO: get the real signal quality
  	wstats->qual.noise = bcm->stats.noise;
-	wstats->qual.updated = IW_QUAL_QUAL_UPDATED | IW_QUAL_LEVEL_UPDATED |
-			IW_QUAL_NOISE_UPDATED;
+	wstats->qual.updated = IW_QUAL_ALL_UPDATED;
  	wstats->discard.code = bcm->ieee->ieee_stats.rx_discards_undecryptable;
  	wstats->discard.retries = bcm->ieee->ieee_stats.tx_retry_limit_exceeded;
  	wstats->discard.nwid = bcm->ieee->ieee_stats.tx_discards_wrong_sa;

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