svn commit: r243588 - head/sys/dev/ath/ath_hal/ar5212

[Adrian Chadd]

Author: adrian
Date: Tue Nov 27 02:18:41 2012
New Revision: 243588
URL: http://svnweb.freebsd.org/changeset/base/243588

Log:
  When programming the beacon timer configuration, be very explicit about
  what the maximum legal values are.
  
  The current beacon timer configuration from TDMA wraps things at
  HAL_BEACON_PERIOD-1 TU.  For the 11a chips this is fine, but for
  the 11n chips it's not enough resolution.  Since the 11a chips have a
  limit on what's "valid", just enforce this so when I do write larger
  values in, they get suitably wrapped before programming.
  
  Tested:
  
  * AR5413, TDMA slave
  
  Todo:
  
  * Run it for a (lot) longer on a clear channel, ensure that no strange
    slippages occur.
  * Re-validate this on STA configurations, just to be sure.

Modified:
  head/sys/dev/ath/ath_hal/ar5212/ar5212_beacon.c

Modified: head/sys/dev/ath/ath_hal/ar5212/ar5212_beacon.c
==============================================================================
--- head/sys/dev/ath/ath_hal/ar5212/ar5212_beacon.c	Tue Nov 27 02:03:41 2012	(r243587)
+++ head/sys/dev/ath/ath_hal/ar5212/ar5212_beacon.c	Tue Nov 27 02:18:41 2012	(r243588)
@@ -46,10 +46,19 @@ ar5212SetBeaconTimers(struct ath_hal *ah
 {
 	struct ath_hal_5212 *ahp = AH5212(ah);
 
-	OS_REG_WRITE(ah, AR_TIMER0, bt->bt_nexttbtt);
-	OS_REG_WRITE(ah, AR_TIMER1, bt->bt_nextdba);
-	OS_REG_WRITE(ah, AR_TIMER2, bt->bt_nextswba);
-	OS_REG_WRITE(ah, AR_TIMER3, bt->bt_nextatim);
+	/*
+	 * Limit the timers to their specific resolutions:
+	 *
+	 * + Timer 0 - 0..15 0xffff TU
+	 * + Timer 1 - 0..18 0x7ffff TU/8
+	 * + Timer 2 - 0..24 0x1ffffff TU/8
+	 * + Timer 3 - 0..15 0xffff TU
+	 */
+	OS_REG_WRITE(ah, AR_TIMER0, bt->bt_nexttbtt & 0xffff);
+	OS_REG_WRITE(ah, AR_TIMER1, bt->bt_nextdba & 0x7ffff);
+	OS_REG_WRITE(ah, AR_TIMER2, bt->bt_nextswba & 0x1ffffff);
+	/* XXX force nextatim to be non-zero? */
+	OS_REG_WRITE(ah, AR_TIMER3, bt->bt_nextatim & 0xffff);
 	/*
 	 * Set the Beacon register after setting all timers.
 	 */