aredn: enable ath9k auto distance capability (#367)

configs/common.config

@@ -104,3 +104,4 @@ CONFIG_PACKAGE_kmod-ipip=y
 CONFIG_IMAGEOPT=y
 CONFIG_VERSIONOPT=y
 CONFIG_VERSION_DIST="AREDN"
+CONFIG_PACKAGE_ATH_DYNACK=y

files/www/cgi-bin/setup

@@ -189,12 +189,19 @@ $parms{wifi_txpower} = $wifi_txpower;
 
 if(($parms{button_apply} or $parms{button_save}) and $wifi_enable )
 {
-    if($wifi_distance < 1 or $wifi_distance =~ /\D/)
+    if($wifi_distance < 0 or $wifi_distance =~ /\D/)
     {
         push (@errors, "invalid distance value");
     } else {
         $cmd = "";
+	if ( $wifi_distance eq "0" )
+	{
+            $cmd .= "iw phy ${phy} set distance auto >/dev/null 2>&1;";
+	}
+	else
+	{
 	    $cmd .= "iw phy ${phy} set distance $wifi_distance >/dev/null 2>&1;";
+	}
         $cmd .= "iw dev $wifiintf set txpower fixed ${wifi_txpower}00 >/dev/null 2>&1;";
         system $cmd;
     }
@@ -555,13 +562,9 @@ function updDist(x) {
     document.getElementsByName('wifi_distance_disp_meters')[0].value = xc;
     dist_meters.value = xc;
 
-    // if default, then ALERT!
-    if(dist_meters.value==0) {
-        distBox.className = 'dist-alert';
-    } else {
+    // default of 0 means 'auto', so full range is always dist-norm
     distBox.className = 'dist-norm';
 }
-}
 
 
 function calcDistance(x) {
@@ -757,15 +760,15 @@ if ( ${wifi_enable} )
     for($i = wifi_maxpower($wifi_channel); $i >= 1; --$i) { selopt($i+$txpoweroffset ." dBm", $i, $wifi_txpower) }
     print "</select>&nbsp;&nbsp;<a href=\"/help.html\#power\" target=\"_blank\"><img src=\"/qmark.png\"></a></td></tr>\n";
 
-    print "<tr id='dist' class='dist-norm'><td>Distance to<br />FARTHEST Neighbor</td>\n";
+    print "<tr id='dist' class='dist-norm'><td>Distance to<br/>FARTHEST Neighbor<br/><h3>'0' is auto</h3></td>\n";
 
     $wifi_distance=int($wifi_distance);  # in meters
     $wifi_distance_disp_km=int($wifi_distance/1000);
     $wifi_distance_disp_miles=sprintf("%.2f",$wifi_distance_disp_km*.621371192);
 
-    print "<td><input disabled size=6 type=text name='wifi_distance_disp_miles' value='$wifi_distance_disp_miles' title='Distance to the farthest neighbor'>&nbsp;miles<br />";
-    print "<input disabled size=6 type=text size=4 name='wifi_distance_disp_km' value='$wifi_distance_disp_km' title='Distance to the farthest neighbor'>&nbsp;kilometers<br />";
-    print "<input disabled size=6 type=text size=4 name='wifi_distance_disp_meters' value='$wifi_distance' title='Distance to the farthest neighbor'>&nbsp;meters<br />";
+    print "<td><input disabled size=6 type=text name='wifi_distance_disp_miles' value='$wifi_distance_disp_miles' title='Distance to the farthest neighbor'>&nbsp;mi<br />";
+    print "<input disabled size=6 type=text size=4 name='wifi_distance_disp_km' value='$wifi_distance_disp_km' title='Distance to the farthest neighbor'>&nbsp;km<br />";
+    print "<input disabled size=6 type=text size=4 name='wifi_distance_disp_meters' value='$wifi_distance' title='Distance to the farthest neighbor'>&nbsp;m<br />";
 
     print "<input id='distance_slider' type='range' min='0' max='150' step='1' value='$wifi_distance_disp_km' oninput='updDist(this.value)' onchange='updDist(this.value)' /><br />";
     print "<input type='hidden' size='6' name='wifi_distance' value='$wifi_distance' />";

files/www/help.html

@@ -371,12 +371,18 @@ The <strong>Distance</strong> setting adjusts the RF retry timer
 to define how long the transmitter will wait for an acknowledgement
 from a Neighbor station. If the distance parameter is too short, then
 the transmitter will send duplicate data packets before the acknowledgement
-has had time to return.  This value is only applicable to nodes that can
+has had time to return. If the distance parameter is too long, then the 
+transmitter will wait extra time before considering the data lost to re-transmit.
+This value is only applicable to nodes that can
 be communicated with directly over RF and not multiple hop nodes on the 
 greater mesh network.  The value should be set to the distance in meters
 to the farthest direct RF node you expect to communicate with. Change
 the distance value by moving the slider. Distance values will be in multiples
-of 1000 meters (approximately 0.62 miles). A value of zero is not allowed.
+of 1000 meters (approximately 0.62 miles).  A value of '0' will cause
+the radio to auto determine the RF retry timer based on measuring the
+actual time it takes acknowledgement packets to be received back.  The
+automatic timer is set using a Exponential Weighted Moving Average (EWMA) method. 
+'auto' is the default setting and in most all situations the optimal setting.
 The best way to test an optimal distance settings is to do an 'iperf' 
 test directly between 2 nodes to measure the performance of this RF 
 channel.   Try different distance settings to peak out the iperf throughput.

patches/712-auto-distance-settings.patch

@@ -0,0 +1,54 @@
+Index: openwrt/package/kernel/mac80211/patches/569-dynack-aredn-long-dist-defaults.patch
+===================================================================
+--- /dev/null
++++ openwrt/package/kernel/mac80211/patches/569-dynack-aredn-long-dist-defaults.patch
+@@ -0,0 +1,32 @@
++--- a/drivers/net/wireless/ath/ath9k/dynack.c
+++++ b/drivers/net/wireless/ath/ath9k/dynack.c
++@@ -21,7 +21,8 @@
++ #define COMPUTE_TO		(5 * HZ)
++ #define LATEACK_DELAY		(10 * HZ)
++ #define LATEACK_TO		256
++-#define MAX_DELAY		300
+++/* AREDN max distance set to 150km */
+++#define MAX_DELAY		1054	
++ #define EWMA_LEVEL		96
++ #define EWMA_DIV		128
++ 
++@@ -293,7 +294,8 @@
++ void ath_dynack_node_init(struct ath_hw *ah, struct ath_node *an)
++ {
++ 	/* ackto = slottime + sifs + air delay */
++-	u32 ackto = 9 + 16 + 64;
+++	/* AREDN starting point is 20km */
+++	u32 ackto = 9 + 16 + 171;
++ 	struct ath_dynack *da = &ah->dynack;
++ 
++ 	an->ackto = ackto;
++@@ -328,7 +330,8 @@
++ void ath_dynack_reset(struct ath_hw *ah)
++ {
++ 	/* ackto = slottime + sifs + air delay */
++-	u32 ackto = 9 + 16 + 64;
+++	/* AREDN starting point is 20km */
+++	u32 ackto = 9 + 16 + 171;
++ 	struct ath_dynack *da = &ah->dynack;
++ 
++ 	da->lto = jiffies;
+Index: openwrt/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh
+===================================================================
+--- openwrt.orig/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh
++++ openwrt/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh
+@@ -788,7 +788,11 @@ drv_mac80211_setup() {
+ 
+ 	iw phy "$phy" set antenna $txantenna $rxantenna >/dev/null 2>&1
+ 	iw phy "$phy" set antenna_gain $antenna_gain
+-	iw phy "$phy" set distance "$distance"
++	if [ $distance -eq 0 -a -d /sys/kernel/debug/ieee80211/$phy/ath9k ]; then
++		iw phy "$phy" set distance auto
++	else
++		iw phy "$phy" set distance "$distance"
++	fi
+ 
+ 	[ -n "$frag" ] && iw phy "$phy" set frag "${frag%%.*}"
+ 	[ -n "$rts" ] && iw phy "$phy" set rts "${rts%%.*}"

patches/series

@@ -21,3 +21,4 @@
 709-iperf-fw-restart.patch
 710-no-ping6-traceroute6.patch
 711-nano-xw-switch-config.patch
+712-auto-distance-settings.patch