ath9k: Adjust AP beacon tsf based on station context

In multi channel context (AP + STA case), adjust the TSF time of
the AP chanctx to keep its beacons at half beacon interval offset
relative to the STA chanctx.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index 02f3098..a4646a0 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -335,6 +335,7 @@ struct ath_chanctx {
        struct ath9k_hw_cal_data caldata;
        struct timespec tsf_ts;
        u64 tsf_val;
+       u32 last_beacon;
 
        u16 txpower;
        bool offchannel;
@@ -348,6 +349,7 @@ enum ath_chanctx_event {
        ATH_CHANCTX_EVENT_BEACON_PREPARE,
        ATH_CHANCTX_EVENT_BEACON_SENT,
        ATH_CHANCTX_EVENT_TSF_TIMER,
+       ATH_CHANCTX_EVENT_BEACON_RECEIVED,
 };
 
 enum ath_chanctx_state {

diff --git a/drivers/net/wireless/ath/ath9k/channel.c b/drivers/net/wireless/ath/ath9k/channel.c
index 4793de0..6ea806c 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/channel.c
+++ b/drivers/net/wireless/ath/ath9k/channel.c
@@ -382,10 +382,51 @@ void ath_chanctx_offchan_switch(struct ath_softc *sc,
        ath_chanctx_switch(sc, &sc->offchannel.chan, &chandef);
 }
 
+static struct ath_chanctx *
+ath_chanctx_get_next(struct ath_softc *sc, struct ath_chanctx *ctx)
+{
+       int idx = ctx - &sc->chanctx[0];
+
+       return &sc->chanctx[!idx];
+}
+
+static void ath_chanctx_adjust_tbtt_delta(struct ath_softc *sc)
+{
+       struct ath_chanctx *prev, *cur;
+       struct timespec ts;
+       u32 cur_tsf, prev_tsf, beacon_int;
+       s32 offset;
+
+       beacon_int = TU_TO_USEC(sc->cur_chan->beacon.beacon_interval);
+
+       cur = sc->cur_chan;
+       prev = ath_chanctx_get_next(sc, cur);
+
+       getrawmonotonic(&ts);
+       cur_tsf = (u32) cur->tsf_val +
+                 ath9k_hw_get_tsf_offset(&cur->tsf_ts, &ts);
+
+       prev_tsf = prev->last_beacon - (u32) prev->tsf_val + cur_tsf;
+       prev_tsf -= ath9k_hw_get_tsf_offset(&prev->tsf_ts, &ts);
+
+       /* Adjust the TSF time of the AP chanctx to keep its beacons
+        * at half beacon interval offset relative to the STA chanctx.
+        */
+       offset = cur_tsf - prev_tsf;
+
+       /* Ignore stale data or spurious timestamps */
+       if (offset < 0 || offset > 3 * beacon_int)
+               return;
+
+       offset = beacon_int / 2 - (offset % beacon_int);
+       prev->tsf_val += offset;
+}
+
 void ath_chanctx_event(struct ath_softc *sc, struct ieee80211_vif *vif,
                       enum ath_chanctx_event ev)
 {
        struct ath_hw *ah = sc->sc_ah;
+       struct ath_common *common = ath9k_hw_common(ah);
        struct ath_vif *avp = NULL;
        u32 tsf_time;
        bool noa_changed = false;
@@ -410,6 +451,7 @@ void ath_chanctx_event(struct ath_softc *sc, struct ieee80211_vif *vif,
                tsf_time = TU_TO_USEC(sc->cur_chan->beacon.beacon_interval);
                tsf_time = sc->sched.next_tbtt + tsf_time / 4;
                sc->sched.switch_start_time = tsf_time;
+               sc->cur_chan->last_beacon = sc->sched.next_tbtt;
 
                if (sc->sched.offchannel_duration) {
                        noa_changed = true;
@@ -441,6 +483,12 @@ void ath_chanctx_event(struct ath_softc *sc, struct ieee80211_vif *vif,
                sc->sched.state = ATH_CHANCTX_STATE_SWITCH;
                ieee80211_queue_work(sc->hw, &sc->chanctx_work);
                break;
+       case ATH_CHANCTX_EVENT_BEACON_RECEIVED:
+               if (!test_bit(ATH_OP_MULTI_CHANNEL, &common->op_flags))
+                       break;
+
+               ath_chanctx_adjust_tbtt_delta(sc);
+               break;
        }
 
        spin_unlock_bh(&sc->chan_lock);

diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index 7b9c7e5..74ab1d0 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -892,6 +892,11 @@ static int ath9k_rx_skb_preprocess(struct ath_softc *sc,
                return -EINVAL;
        }
 
+       if (rx_stats->is_mybeacon) {
+               sc->sched.next_tbtt = rx_stats->rs_tstamp;
+               ath_chanctx_event(sc, NULL, ATH_CHANCTX_EVENT_BEACON_RECEIVED);
+       }
+
        ath9k_cmn_process_rssi(common, hw, rx_stats, rx_status);
 
        rx_status->band = ah->curchan->chan->band;