2 files changed, 67 insertions, 13 deletions

diff --git a/drivers/net/wireless/ath5k/base.c b/drivers/net/wireless/ath5k/base.c
index c49061c51688..eb98284cba92 100644
--- a/drivers/net/wireless/ath5k/base.c
+++ b/drivers/net/wireless/ath5k/base.c
@@ -1640,6 +1640,34 @@ ath5k_rx_decrypted(struct ath5k_softc *sc, struct ath5k_desc *ds,
         return 0;
 }
 
+
+static void
+ath5k_check_ibss_hw_merge(struct ath5k_softc *sc, struct sk_buff *skb)
+{
+        u32 hw_tu;
+        struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *)skb->data;
+
+        if ((mgmt->frame_control & IEEE80211_FCTL_FTYPE) ==
+                IEEE80211_FTYPE_MGMT &&
+            (mgmt->frame_control & IEEE80211_FCTL_STYPE) ==
+                IEEE80211_STYPE_BEACON &&
+            mgmt->u.beacon.capab_info & WLAN_CAPABILITY_IBSS &&
+            memcmp(mgmt->bssid, sc->ah->ah_bssid, ETH_ALEN) == 0) {
+                /*
+                 * Received an IBSS beacon with the same BSSID. Hardware might
+                 * have updated the TSF, check if we need to update timers.
+                 */
+                hw_tu = TSF_TO_TU(ath5k_hw_get_tsf64(sc->ah));
+                if (hw_tu >= sc->nexttbtt) {
+                        ath5k_beacon_update_timers(sc,
+                                mgmt->u.beacon.timestamp);
+                        ATH5K_DBG_UNLIMIT(sc, ATH5K_DEBUG_BEACON,
+                                "detected HW merge from received beacon\n");
+                }
+        }
+}
+
+
 static void
 ath5k_tasklet_rx(unsigned long data)
 {
@@ -1767,6 +1795,10 @@ accept:
 
                 ath5k_debug_dump_skb(sc, skb, "RX  ", 0);
 
+                /* check beacons in IBSS mode */
+                if (sc->opmode == IEEE80211_IF_TYPE_IBSS)
+                        ath5k_check_ibss_hw_merge(sc, skb);
+
                 __ieee80211_rx(sc->hw, skb, &rxs);
                 sc->led_rxrate = ds->ds_rxstat.rs_rate;
                 ath5k_led_event(sc, ATH_LED_RX);
@@ -2057,6 +2089,8 @@ ath5k_beacon_update_timers(struct ath5k_softc *sc, u64 bc_tsf)
         }
 #undef FUDGE
 
+        sc->nexttbtt = nexttbtt;
+
         intval |= AR5K_BEACON_ENA;
         ath5k_hw_init_beacon(ah, nexttbtt, intval);
 
@@ -2084,16 +2118,19 @@ ath5k_beacon_update_timers(struct ath5k_softc *sc, u64 bc_tsf)
 }
 
 
-/*
- * Configure the beacon timers and interrupts based on the operating mode
+/**
+ * ath5k_beacon_config - Configure the beacon queues and interrupts
+ *
+ * @sc: struct ath5k_softc pointer we are operating on
  *
  * When operating in station mode we want to receive a BMISS interrupt when we
  * stop seeing beacons from the AP we've associated with so we can look for
  * another AP to associate with.
  *
- * In IBSS mode we need to configure the beacon timers and use a self-linked tx
- * descriptor if possible. If the hardware cannot deal with that we enable SWBA
- * interrupts to send the beacons from the interrupt handler.
+ * In IBSS mode we use a self-linked tx descriptor if possible. We enable SWBA
+ * interrupts to detect HW merges only.
+ *
+ * AP mode is missing.
  */
 static void
 ath5k_beacon_config(struct ath5k_softc *sc)
@@ -2107,17 +2144,17 @@ ath5k_beacon_config(struct ath5k_softc *sc)
                 sc->imask |= AR5K_INT_BMISS;
         } else if (sc->opmode == IEEE80211_IF_TYPE_IBSS) {
                 /*
-                 * In IBSS mode enable the beacon timers but only enable SWBA
-                 * interrupts if we need to manually prepare beacon frames.
-                 * Otherwise we use a self-linked tx descriptor and let the
-                 * hardware deal with things. In that case we have to load it
+                 * In IBSS mode we use a self-linked tx descriptor and let the
+                 * hardware send the beacons automatically. We have to load it
                  * only once here.
+                 * We use the SWBA interrupt only to keep track of the beacon
+                 * timers in order to detect HW merges (automatic TSF updates).
                  */
                 ath5k_beaconq_config(sc);
 
-                if (!ath5k_hw_hasveol(ah))
-                        sc->imask |= AR5K_INT_SWBA;
-                else
+                sc->imask |= AR5K_INT_SWBA;
+
+                if (ath5k_hw_hasveol(ah))
                         ath5k_beacon_send(sc);
         }
         /* TODO else AP */
@@ -2320,8 +2357,24 @@ ath5k_intr(int irq, void *dev_id)
                                 * Handle beacon transmission directly; deferring
                                 * this is too slow to meet timing constraints
                                 * under load.
+                                *
+                                * In IBSS mode we use this interrupt just to
+                                * keep track of the next TBTT (target beacon
+                                * transmission time) in order to detect hardware
+                                * merges (TSF updates).
                                 */
-                                ath5k_beacon_send(sc);
+                                if (sc->opmode == IEEE80211_IF_TYPE_IBSS) {
+                                         /* XXX: only if VEOL suppported */
+                                        u64 tsf = ath5k_hw_get_tsf64(ah);
+                                        sc->nexttbtt += sc->bintval;
+                                        ATH5K_DBG(sc, ATH5K_DEBUG_BEACON,
+                                                "SWBA nexttbtt: %x hw_tu: %x "
+                                                "TSF: %llx\n",
+                                                sc->nexttbtt,
+                                                TSF_TO_TU(tsf), tsf);
+                                } else {
+                                        ath5k_beacon_send(sc);
+                                }
                         }
                         if (status & AR5K_INT_RXEOL) {
                                 /*
diff --git a/drivers/net/wireless/ath5k/base.h b/drivers/net/wireless/ath5k/base.h
index 20c946926090..8287ae787f12 100644
--- a/drivers/net/wireless/ath5k/base.h
+++ b/drivers/net/wireless/ath5k/base.h
@@ -166,6 +166,7 @@ struct ath5k_softc {
                                 bmisscount,     /* missed beacon transmits */
                                 bintval,        /* beacon interval in TU */
                                 bsent;
+        unsigned int            nexttbtt;       /* next beacon time in TU */
 
         struct timer_list       calib_tim;      /* calibration timer */
 };