svn commit: r221779 - head/sys/dev/ath/ath_hal/ar5416

[Adrian Chadd]

Author: adrian
Date: Wed May 11 13:40:13 2011
New Revision: 221779
URL: http://svn.freebsd.org/changeset/base/221779

Log:
  Make the NF calibration logic (hopefully!) more resistive to noisy
  environments.
  
  In setups where NF calibration can take a while, don't load the CCA
  and kick off a new NF calibration if the previous one hasn't yet
  completed. This shouldn't happen unless the environment is noisy but
  those exist (hi phk!).
  
  Here, if the previous NF hasn't completed when ar5416LoadNf() is run
  (which reads the NF), it skips updating the history buffer, loading
  the NF CCA array and kicking off the next NF cal. It's hoped it'll
  occur in the next long calibration interval.
  
  Obtained from:	Atheros, ath9k, my local HAL

Modified:
  head/sys/dev/ath/ath_hal/ar5416/ar5416_cal.c

Modified: head/sys/dev/ath/ath_hal/ar5416/ar5416_cal.c
==============================================================================
--- head/sys/dev/ath/ath_hal/ar5416/ar5416_cal.c	Wed May 11 13:25:43 2011	(r221778)
+++ head/sys/dev/ath/ath_hal/ar5416/ar5416_cal.c	Wed May 11 13:40:13 2011	(r221779)
@@ -442,6 +442,7 @@ ar5416PerCalibrationN(struct ath_hal *ah
 	struct ar5416PerCal *cal = &AH5416(ah)->ah_cal;
 	HAL_CAL_LIST *currCal = cal->cal_curr;
 	HAL_CHANNEL_INTERNAL *ichan;
+	int r;
 
 	OS_MARK(ah, AH_MARK_PERCAL, chan->ic_freq);
 
@@ -498,17 +499,24 @@ ar5416PerCalibrationN(struct ath_hal *ah
 		 * Get the value from the previous NF cal
 		 * and update the history buffer.
 		 */
-		ar5416GetNf(ah, chan);
-
-		/* 
-		 * Load the NF from history buffer of the current channel.
-		 * NF is slow time-variant, so it is OK to use a
-		 * historical value.
-		 */
-		ar5416LoadNF(ah, AH_PRIVATE(ah)->ah_curchan);
+		r = ar5416GetNf(ah, chan);
+		if (r <= 0) {
+			/* NF calibration result isn't valid */
+			HALDEBUG(ah, HAL_DEBUG_UNMASKABLE, "%s: NF calibration"
+			    " didn't finish; delaying CCA\n", __func__);
+		} else {
+			/* 
+			 * NF calibration result is valid.
+			 *
+			 * Load the NF from history buffer of the current channel.
+			 * NF is slow time-variant, so it is OK to use a
+			 * historical value.
+			 */
+			ar5416LoadNF(ah, AH_PRIVATE(ah)->ah_curchan);
 
-		/* start NF calibration, without updating BB NF register*/
-		ar5416StartNFCal(ah);
+			/* start NF calibration, without updating BB NF register*/
+			ar5416StartNFCal(ah);
+		}
 	}
 	return AH_TRUE;
 }
@@ -758,17 +766,22 @@ ar5416SanitizeNF(struct ath_hal *ah, int
 
 /*
  * Read the NF and check it against the noise floor threshhold
+ *
+ * Return 0 if the NF calibration hadn't finished, 0 if it was
+ * invalid, or > 0 for a valid NF reading.
  */
 static int16_t
 ar5416GetNf(struct ath_hal *ah, struct ieee80211_channel *chan)
 {
 	int16_t nf, nfThresh;
 	int i;
+	int retval = 0;
 
 	if (ar5212IsNFCalInProgress(ah)) {
 		HALDEBUG(ah, HAL_DEBUG_ANY,
 		    "%s: NF didn't complete in calibration window\n", __func__);
 		nf = 0;
+		retval = -1;	/* NF didn't finish */
 	} else {
 		/* Finished NF cal, check against threshold */
 		int16_t nfarray[NUM_NOISEFLOOR_READINGS] = { 0 };
@@ -780,7 +793,7 @@ ar5416GetNf(struct ath_hal *ah, struct i
 		ar5416SanitizeNF(ah, nfarray);
 		if (ar5416GetEepromNoiseFloorThresh(ah, chan, &nfThresh)) {
 			if (nf > nfThresh) {
-				HALDEBUG(ah, HAL_DEBUG_ANY,
+				HALDEBUG(ah, HAL_DEBUG_UNMASKABLE,
 				    "%s: noise floor failed detected; "
 				    "detected %d, threshold %d\n", __func__,
 				    nf, nfThresh);
@@ -791,9 +804,11 @@ ar5416GetNf(struct ath_hal *ah, struct i
 				 */
 				chan->ic_state |= IEEE80211_CHANSTATE_CWINT;
 				nf = 0;
+				retval = 0;
 			}
 		} else {
 			nf = 0;
+			retval = 0;
 		}
 		/* Update MIMO channel statistics, regardless of validity or not (for now) */
 		for (i = 0; i < 3; i++) {
@@ -804,6 +819,7 @@ ar5416GetNf(struct ath_hal *ah, struct i
 
 		ar5416UpdateNFHistBuff(ah, AH5416(ah)->ah_cal.nfCalHist, nfarray);
 		ichan->rawNoiseFloor = nf;
+		retval = nf;
 	}
-	return nf;
+	return retval;
 }