ath5k: Calibration re-work

Noise floor calibration does not interfere with traffic and should run more
often as part of our "short calibration". The full calibration is not the
noise floor calibration but the AGC + Gain_F (on RF5111 and RF5112) calibration
and should run less often because it does interfere with traffic.

So

Short calibration -> I/Q & NF Calibration
Long calibration -> Short + AGC + Gain_F

This patch was for some time on my pub/ dir on www.kernel.org and has been tested
by a few people and me. I think it's O.K. to go in.

I also changed ah_calibration to ah_iq_cal_needed to make more sense.

v2 Use a workqueue instead of a tasklet for calibration

Signed-off-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 78 insertions, 34 deletions

diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c
index 47194a4e365..a8cb1c7f4bf 100644
--- a/drivers/net/wireless/ath/ath5k/base.c
+++ b/drivers/net/wireless/ath/ath5k/base.c
@@ -2112,16 +2112,29 @@ static void
 ath5k_intr_calibration_poll(struct ath5k_hw *ah)
 {
 	if (time_is_before_eq_jiffies(ah->ah_cal_next_ani) &&
-	    !(ah->ah_cal_mask & AR5K_CALIBRATION_FULL)) {
-		/* run ANI only when full calibration is not active */
+	   !(ah->ah_cal_mask & AR5K_CALIBRATION_FULL) &&
+	   !(ah->ah_cal_mask & AR5K_CALIBRATION_SHORT)) {
+
+		/* Run ANI only when calibration is not active */
+
 		ah->ah_cal_next_ani = jiffies +
 			msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_ANI);
 		tasklet_schedule(&ah->ani_tasklet);
 
-	} else if (time_is_before_eq_jiffies(ah->ah_cal_next_full)) {
-		ah->ah_cal_next_full = jiffies +
-			msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_FULL);
-		tasklet_schedule(&ah->calib);
+	} else if (time_is_before_eq_jiffies(ah->ah_cal_next_short) &&
+		!(ah->ah_cal_mask & AR5K_CALIBRATION_FULL) &&
+		!(ah->ah_cal_mask & AR5K_CALIBRATION_SHORT)) {
+
+		/* Run calibration only when another calibration
+		 * is not running.
+		 *
+		 * Note: This is for both full/short calibration,
+		 * if it's time for a full one, ath5k_calibrate_work will deal
+		 * with it. */
+
+		ah->ah_cal_next_short = jiffies +
+			msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_SHORT);
+		ieee80211_queue_work(ah->hw, &ah->calib_work);
 	}
 	/* we could use SWI to generate enough interrupts to meet our
 	 * calibration interval requirements, if necessary:
@@ -2286,41 +2299,58 @@ ath5k_intr(int irq, void *dev_id)
  * for temperature/environment changes.
  */
 static void
-ath5k_tasklet_calibrate(unsigned long data)
+ath5k_calibrate_work(struct work_struct *work)
 {
-	struct ath5k_hw *ah = (void *)data;
+	struct ath5k_hw *ah = container_of(work, struct ath5k_hw,
+		calib_work);
+
+	/* Should we run a full calibration ? */
+	if (time_is_before_eq_jiffies(ah->ah_cal_next_full)) {
+
+		ah->ah_cal_next_full = jiffies +
+			msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_FULL);
+		ah->ah_cal_mask |= AR5K_CALIBRATION_FULL;
+
+		ATH5K_DBG(ah, ATH5K_DEBUG_CALIBRATE,
+				"running full calibration\n");
+
+		if (ath5k_hw_gainf_calibrate(ah) == AR5K_RFGAIN_NEED_CHANGE) {
+			/*
+			 * Rfgain is out of bounds, reset the chip
+			 * to load new gain values.
+			 */
+			ATH5K_DBG(ah, ATH5K_DEBUG_RESET,
+					"got new rfgain, resetting\n");
+			ieee80211_queue_work(ah->hw, &ah->reset_work);
+		}
+
+		/* TODO: On full calibration we should stop TX here,
+		 * so that it doesn't interfere (mostly due to gain_f
+		 * calibration that messes with tx packets -see phy.c).
+		 *
+		 * NOTE: Stopping the queues from above is not enough
+		 * to stop TX but saves us from disconecting (at least
+		 * we don't lose packets). */
+		ieee80211_stop_queues(ah->hw);
+	} else
+		ah->ah_cal_mask |= AR5K_CALIBRATION_SHORT;
 
-	/* Only full calibration for now */
-	ah->ah_cal_mask |= AR5K_CALIBRATION_FULL;
 
 	ATH5K_DBG(ah, ATH5K_DEBUG_CALIBRATE, "channel %u/%x\n",
 		ieee80211_frequency_to_channel(ah->curchan->center_freq),
 		ah->curchan->hw_value);
 
-	if (ath5k_hw_gainf_calibrate(ah) == AR5K_RFGAIN_NEED_CHANGE) {
-		/*
-		 * Rfgain is out of bounds, reset the chip
-		 * to load new gain values.
-		 */
-		ATH5K_DBG(ah, ATH5K_DEBUG_RESET, "calibration, resetting\n");
-		ieee80211_queue_work(ah->hw, &ah->reset_work);
-	}
 	if (ath5k_hw_phy_calibrate(ah, ah->curchan))
 		ATH5K_ERR(ah, "calibration of channel %u failed\n",
 			ieee80211_frequency_to_channel(
 				ah->curchan->center_freq));
 
-	/* Noise floor calibration interrupts rx/tx path while I/Q calibration
-	 * doesn't.
-	 * TODO: We should stop TX here, so that it doesn't interfere.
-	 * Note that stopping the queues is not enough to stop TX! */
-	if (time_is_before_eq_jiffies(ah->ah_cal_next_nf)) {
-		ah->ah_cal_next_nf = jiffies +
-			msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_NF);
-		ath5k_hw_update_noise_floor(ah);
-	}
-
-	ah->ah_cal_mask &= ~AR5K_CALIBRATION_FULL;
+	/* Clear calibration flags */
+	if (ah->ah_cal_mask & AR5K_CALIBRATION_FULL) {
+		ieee80211_wake_queues(ah->hw);
+		ah->ah_cal_mask &= ~AR5K_CALIBRATION_FULL;
+	} else if (ah->ah_cal_mask & AR5K_CALIBRATION_SHORT)
+		ah->ah_cal_mask &= ~AR5K_CALIBRATION_SHORT;
 }
 
 
@@ -2639,7 +2669,6 @@ static void ath5k_stop_tasklets(struct ath5k_hw *ah)
 	ah->tx_pending = false;
 	tasklet_kill(&ah->rxtq);
 	tasklet_kill(&ah->txtq);
-	tasklet_kill(&ah->calib);
 	tasklet_kill(&ah->beacontq);
 	tasklet_kill(&ah->ani_tasklet);
 }
@@ -2743,9 +2772,24 @@ ath5k_reset(struct ath5k_hw *ah, struct ieee80211_channel *chan,
 
 	ath5k_ani_init(ah, ani_mode);
 
-	ah->ah_cal_next_full = jiffies + msecs_to_jiffies(100);
-	ah->ah_cal_next_ani = jiffies;
-	ah->ah_cal_next_nf = jiffies;
+	/*
+	 * Set calibration intervals
+	 *
+	 * Note: We don't need to run calibration imediately
+	 * since some initial calibration is done on reset
+	 * even for fast channel switching. Also on scanning
+	 * this will get set again and again and it won't get
+	 * executed unless we connect somewhere and spend some
+	 * time on the channel (that's what calibration needs
+	 * anyway to be accurate).
+	 */
+	ah->ah_cal_next_full = jiffies +
+		msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_FULL);
+	ah->ah_cal_next_ani = jiffies +
+		msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_ANI);
+	ah->ah_cal_next_short = jiffies +
+		msecs_to_jiffies(ATH5K_TUNE_CALIBRATION_INTERVAL_SHORT);
+
 	ewma_init(&ah->ah_beacon_rssi_avg, 1024, 8);
 
 	/* clear survey data and cycle counters */
@@ -2895,11 +2939,11 @@ ath5k_init(struct ieee80211_hw *hw)
 
 	tasklet_init(&ah->rxtq, ath5k_tasklet_rx, (unsigned long)ah);
 	tasklet_init(&ah->txtq, ath5k_tasklet_tx, (unsigned long)ah);
-	tasklet_init(&ah->calib, ath5k_tasklet_calibrate, (unsigned long)ah);
 	tasklet_init(&ah->beacontq, ath5k_tasklet_beacon, (unsigned long)ah);
 	tasklet_init(&ah->ani_tasklet, ath5k_tasklet_ani, (unsigned long)ah);
 
 	INIT_WORK(&ah->reset_work, ath5k_reset_work);
+	INIT_WORK(&ah->calib_work, ath5k_calibrate_work);
 	INIT_DELAYED_WORK(&ah->tx_complete_work, ath5k_tx_complete_poll_work);
 
 	ret = ath5k_hw_common(ah)->bus_ops->eeprom_read_mac(ah, mac);