Changeset 3635

Timestamp:

05/16/08 18:09:36 (5 months ago)

Author:

br1

Message:

add IEEE80211_TSF_TO_TU macro again and explain it once there instead of
open coding >> 10 and putting notes all over the place.

Files:

• madwifi/trunk/ath/if_ath.c (modified) (4 diffs)
• madwifi/trunk/net80211/ieee80211_var.h (modified) (1 diff)

madwifi/trunk/ath/if_ath.c

@@ -5259 +5259 @@
-                u_int32_t tsftu;
-
-hw_tsf >> 10; /* NB: 64 -> 32: See note far above. */
+IEEE80211_TSF_TO_TU(hw_tsf);
-                slot = ((tsftu % ic->ic_lintval) * ath_maxvaps) / ic->ic_lintval;
-                vap = sc->sc_bslot[(slot + 1) % ath_maxvaps];
@@ -5453 +5453 @@
- * Note : TBTT is Target Beacon Transmission Time (see IEEE 802.11-1999: 4 &
- * 11.2.1.3).
- *
- * Note: TSF is right shifter by 10 and then put into a 32-bit int, which will 
- * truncate. This does not affect the calculation as long as no more than one 
- * overflow/wraparound occurs between beacons. This is not going to happen as
- * (2^(32 + 10 - 1) - 1)us is a really long time.
- */
-static void
@@ -5477 +5472 @@
-        hw_tsf = ath_hal_gettsf64(ah);
-        tsf = le64_to_cpu(ni->ni_tstamp.tsf);
-hw_tsf >> 10
-tsf >> 10; /* NB: 64 -> 32. See note above. */
+IEEE80211_TSF_TO_TU(hw_tsf)
+IEEE80211_TSF_TO_TU(tsf);
-
-        /* We should reset hw TSF only once, so we increment
@@ -6502 +6497 @@
-                         * RUN -> RUN when this happens. */
-                        hw_tsf = ath_hal_gettsf64(sc->sc_ah);
-hw_tsf >> 10
+IEEE80211_TSF_TO_TU(hw_tsf)
-
-                        beacon_tsf = le64_to_cpu(ni->ni_tstamp.tsf);
-beacon_tsf >> 10
+IEEE80211_TSF_TO_TU(beacon_tsf)
-
-                        DPRINTF(sc, ATH_DEBUG_BEACON,

madwifi/trunk/net80211/ieee80211_var.h

@@ -122 +122 @@
-          DEV_NAME(_v->iv_ic->ic_dev))
-
+/*
+ * TU conversions:
+ *
+ * TU is a 32bit value and defined by IEEE802.11 (page 6) as "A measurement of
+ * time equal to 1024 usec (microseconds)".
+ *
+ * TSF is a 64bit value in usec, therefore if we right shift it by 10 bit this
+ * will directly convert it to TU. The rest is truncated to fit into 32 bit.
+ */
+#define IEEE80211_TSF_TO_TU(_tsf)       ((u_int32_t)((_tsf) >> 10))
-#define IEEE80211_MS_TO_TU(x)   (((x) * 1000) / 1024)
-#define IEEE80211_TU_TO_MS(x)   (((x) * 1024) / 1000)