modify the rssi logic a bit to actually return a useful rssi.

The fullmac firmware doesn't seem to populate a useful rssi indicator
in the RX descriptor, so if one plotted said values, they'd basically
look like garbage.

The reference driver implements a "get current rssi" firmware command
which I guess is really meant for station operation only (as hostap
operation would need rssi per station, not a single firmware read.)

So:

* populate sc_currssi during each calibration run;
* use this in the RX path instead of trying to reconstruct the RSSI
  value and passing it around as a pointer;
* do up a quick hack to map the rssi hardware value to some useful
  signal level;
* the survey results provide an RSSI value between 0..100, so just
  do another quick hack to map it into some usefulish signal level;
* supply a faked noise floor - I haven't yet found how to pull it
  out of the firmware.

The scan results and the station RSSI information is now more useful
for indicating signal strength / distance.

1 files changed, 1 insertions, 0 deletions

diff --git a/sys/dev/usb/wlan/if_rsureg.h b/sys/dev/usb/wlan/if_rsureg.h
index 2880197..ddb29a3 100644
--- a/sys/dev/usb/wlan/if_rsureg.h
+++ b/sys/dev/usb/wlan/if_rsureg.h
@@ -764,6 +764,7 @@ struct rsu_softc {
 	int				sc_ht;
 	int				sc_nendpoints;
 	int				sc_curpwrstate;
+	int				sc_currssi;
 
 	u_int				sc_running:1,
 					sc_calibrating:1,