/*
* Return the hardware NextTBTT in TSF
*/
uint64_t
ar5210GetNextTBTT(struct ath_hal *ah)
{
#define TU_TO_TSF(_tu) (((uint64_t)(_tu)) << 10)
return TU_TO_TSF(OS_REG_READ(ah, AR_TIMER0));
#undef TU_TO_TSF
}
/*
* Intercept management frames to collect beacon rssi data
* and to do ibss merges.
*/
void
ath_recv_mgmt(struct ieee80211_node *ni, struct mbuf *m,
int subtype, const struct ieee80211_rx_stats *rxs, int rssi, int nf)
{
struct ieee80211vap *vap = ni->ni_vap;
struct ath_softc *sc = vap->iv_ic->ic_softc;
uint64_t tsf_beacon_old, tsf_beacon;
uint64_t nexttbtt;
int64_t tsf_delta;
int32_t tsf_delta_bmiss;
int32_t tsf_remainder;
uint64_t tsf_beacon_target;
int tsf_intval;
tsf_beacon_old = ((uint64_t) le32dec(ni->ni_tstamp.data + 4)) << 32;
tsf_beacon_old |= le32dec(ni->ni_tstamp.data);
#define TU_TO_TSF(_tu) (((u_int64_t)(_tu)) << 10)
tsf_intval = 1;
if (ni->ni_intval > 0) {
tsf_intval = TU_TO_TSF(ni->ni_intval);
}
#undef TU_TO_TSF
/*
* Call up first so subsequent work can use information
* potentially stored in the node (e.g. for ibss merge).
*/
ATH_VAP(vap)->av_recv_mgmt(ni, m, subtype, rxs, rssi, nf);
switch (subtype) {
case IEEE80211_FC0_SUBTYPE_BEACON:
/*
* Only do the following processing if it's for
* the current BSS.
*
* In scan and IBSS mode we receive all beacons,
* which means we need to filter out stuff
* that isn't for us or we'll end up constantly
* trying to sync / merge to BSSes that aren't
* actually us.
*/
if (IEEE80211_ADDR_EQ(ni->ni_bssid, vap->iv_bss->ni_bssid)) {
/* update rssi statistics for use by the hal */
/* XXX unlocked check against vap->iv_bss? */
ATH_RSSI_LPF(sc->sc_halstats.ns_avgbrssi, rssi);
tsf_beacon = ((uint64_t) le32dec(ni->ni_tstamp.data + 4)) << 32;
tsf_beacon |= le32dec(ni->ni_tstamp.data);
nexttbtt = ath_hal_getnexttbtt(sc->sc_ah);
/*
* Let's calculate the delta and remainder, so we can see
* if the beacon timer from the AP is varying by more than
* a few TU. (Which would be a huge, huge problem.)
*/
tsf_delta = (long long) tsf_beacon - (long long) tsf_beacon_old;
tsf_delta_bmiss = tsf_delta / tsf_intval;
/*
* If our delta is greater than half the beacon interval,
* let's round the bmiss value up to the next beacon
* interval. Ie, we're running really, really early
* on the next beacon.
*/
if (tsf_delta % tsf_intval > (tsf_intval / 2))
tsf_delta_bmiss ++;
tsf_beacon_target = tsf_beacon_old +
(((unsigned long long) tsf_delta_bmiss) * (long long) tsf_intval);
/*
* The remainder using '%' is between 0 .. intval-1.
* If we're actually running too fast, then the remainder
* will be some large number just under intval-1.
* So we need to look at whether we're running
* before or after the target beacon interval
* and if we are, modify how we do the remainder
* calculation.
*/
if (tsf_beacon < tsf_beacon_target) {
tsf_remainder =
-(tsf_intval - ((tsf_beacon - tsf_beacon_old) % tsf_intval));
} else {
tsf_remainder = (tsf_beacon - tsf_beacon_old) % tsf_intval;
}
DPRINTF(sc, ATH_DEBUG_BEACON, "%s: old_tsf=%llu, new_tsf=%llu, target_tsf=%llu, delta=%lld, bmiss=%d, remainder=%d\n",
__func__,
(unsigned long long) tsf_beacon_old,
(unsigned long long) tsf_beacon,
(unsigned long long) tsf_beacon_target,
(long long) tsf_delta,
tsf_delta_bmiss,
tsf_remainder);
DPRINTF(sc, ATH_DEBUG_BEACON, "%s: tsf=%llu, nexttbtt=%llu, delta=%d\n",
__func__,
(unsigned long long) tsf_beacon,
(unsigned long long) nexttbtt,
(int32_t) tsf_beacon - (int32_t) nexttbtt + tsf_intval);
/* We only do syncbeacon on STA VAPs; not on IBSS */
if (vap->iv_opmode == IEEE80211_M_STA &&
sc->sc_syncbeacon &&
ni == vap->iv_bss &&
(vap->iv_state == IEEE80211_S_RUN || vap->iv_state == IEEE80211_S_SLEEP)) {
DPRINTF(sc, ATH_DEBUG_BEACON,
"%s: syncbeacon=1; syncing\n",
__func__);
/*
* Resync beacon timers using the tsf of the beacon
* frame we just received.
*/
ath_beacon_config(sc, vap);
sc->sc_syncbeacon = 0;
}
}
/* fall thru... */
case IEEE80211_FC0_SUBTYPE_PROBE_RESP:
if (vap->iv_opmode == IEEE80211_M_IBSS &&
vap->iv_state == IEEE80211_S_RUN &&
ieee80211_ibss_merge_check(ni)) {
uint32_t rstamp = sc->sc_lastrs->rs_tstamp;
uint64_t tsf = ath_extend_tsf(sc, rstamp,
ath_hal_gettsf64(sc->sc_ah));
/*
* Handle ibss merge as needed; check the tsf on the
* frame before attempting the merge. The 802.11 spec
* says the station should change it's bssid to match
* the oldest station with the same ssid, where oldest
* is determined by the tsf. Note that hardware
* reconfiguration happens through callback to
* ath_newstate as the state machine will go from
* RUN -> RUN when this happens.
*/
if (le64toh(ni->ni_tstamp.tsf) >= tsf) {
DPRINTF(sc, ATH_DEBUG_STATE,
"ibss merge, rstamp %u tsf %ju "
"tstamp %ju\n", rstamp, (uintmax_t)tsf,
(uintmax_t)ni->ni_tstamp.tsf);
(void) ieee80211_ibss_merge(ni);
}
}
break;
}
}
