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

1 files changed, 28 insertions, 12 deletions

diff --git a/sys/dev/ath/ath_hal/ar5416/ar5416_cal.c b/sys/dev/ath/ath_hal/ar5416/ar5416_cal.c
index e39de1d..3336660 100644
--- a/sys/dev/ath/ath_hal/ar5416/ar5416_cal.c
+++ b/sys/dev/ath/ath_hal/ar5416/ar5416_cal.c
@@ -442,6 +442,7 @@ ar5416PerCalibrationN(struct ath_hal *ah, struct ieee80211_channel *chan,
 	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, struct ieee80211_channel *chan,
 		 * 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, int16_t *nf)
 
 /*
  * 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 ieee80211_channel *chan)
 		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 ieee80211_channel *chan)
 				 */
 				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 ieee80211_channel *chan)
 
 		ar5416UpdateNFHistBuff(ah, AH5416(ah)->ah_cal.nfCalHist, nfarray);
 		ichan->rawNoiseFloor = nf;
+		retval = nf;
 	}
-	return nf;
+	return retval;
 }