atheros: put atheros wireless drivers into ath/

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 743 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath9k/beacon.c b/drivers/net/wireless/ath/ath9k/beacon.c
new file mode 100644
index 00000000000..eb4759fc6a0
--- /dev/null
+++ b/drivers/net/wireless/ath/ath9k/beacon.c
@@ -0,0 +1,743 @@
+/*
+ * Copyright (c) 2008-2009 Atheros Communications Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "ath9k.h"
+
+#define FUDGE 2
+
+/*
+ *  This function will modify certain transmit queue properties depending on
+ *  the operating mode of the station (AP or AdHoc).  Parameters are AIFS
+ *  settings and channel width min/max
+*/
+static int ath_beaconq_config(struct ath_softc *sc)
+{
+	struct ath_hw *ah = sc->sc_ah;
+	struct ath9k_tx_queue_info qi;
+
+	ath9k_hw_get_txq_props(ah, sc->beacon.beaconq, &qi);
+	if (sc->sc_ah->opmode == NL80211_IFTYPE_AP) {
+		/* Always burst out beacon and CAB traffic. */
+		qi.tqi_aifs = 1;
+		qi.tqi_cwmin = 0;
+		qi.tqi_cwmax = 0;
+	} else {
+		/* Adhoc mode; important thing is to use 2x cwmin. */
+		qi.tqi_aifs = sc->beacon.beacon_qi.tqi_aifs;
+		qi.tqi_cwmin = 2*sc->beacon.beacon_qi.tqi_cwmin;
+		qi.tqi_cwmax = sc->beacon.beacon_qi.tqi_cwmax;
+	}
+
+	if (!ath9k_hw_set_txq_props(ah, sc->beacon.beaconq, &qi)) {
+		DPRINTF(sc, ATH_DBG_FATAL,
+			"Unable to update h/w beacon queue parameters\n");
+		return 0;
+	} else {
+		ath9k_hw_resettxqueue(ah, sc->beacon.beaconq);
+		return 1;
+	}
+}
+
+/*
+ *  Associates the beacon frame buffer with a transmit descriptor.  Will set
+ *  up all required antenna switch parameters, rate codes, and channel flags.
+ *  Beacons are always sent out at the lowest rate, and are not retried.
+*/
+static void ath_beacon_setup(struct ath_softc *sc, struct ath_vif *avp,
+			     struct ath_buf *bf)
+{
+	struct sk_buff *skb = bf->bf_mpdu;
+	struct ath_hw *ah = sc->sc_ah;
+	struct ath_desc *ds;
+	struct ath9k_11n_rate_series series[4];
+	struct ath_rate_table *rt;
+	int flags, antenna, ctsrate = 0, ctsduration = 0;
+	u8 rate;
+
+	ds = bf->bf_desc;
+	flags = ATH9K_TXDESC_NOACK;
+
+	if (((sc->sc_ah->opmode == NL80211_IFTYPE_ADHOC) ||
+	     (sc->sc_ah->opmode == NL80211_IFTYPE_MESH_POINT)) &&
+	    (ah->caps.hw_caps & ATH9K_HW_CAP_VEOL)) {
+		ds->ds_link = bf->bf_daddr; /* self-linked */
+		flags |= ATH9K_TXDESC_VEOL;
+		/* Let hardware handle antenna switching. */
+		antenna = 0;
+	} else {
+		ds->ds_link = 0;
+		/*
+		 * Switch antenna every beacon.
+		 * Should only switch every beacon period, not for every SWBA
+		 * XXX assumes two antennae
+		 */
+		antenna = ((sc->beacon.ast_be_xmit / sc->nbcnvifs) & 1 ? 2 : 1);
+	}
+
+	ds->ds_data = bf->bf_buf_addr;
+
+	rt = sc->cur_rate_table;
+	rate = rt->info[0].ratecode;
+	if (sc->sc_flags & SC_OP_PREAMBLE_SHORT)
+		rate |= rt->info[0].short_preamble;
+
+	ath9k_hw_set11n_txdesc(ah, ds, skb->len + FCS_LEN,
+			       ATH9K_PKT_TYPE_BEACON,
+			       MAX_RATE_POWER,
+			       ATH9K_TXKEYIX_INVALID,
+			       ATH9K_KEY_TYPE_CLEAR,
+			       flags);
+
+	/* NB: beacon's BufLen must be a multiple of 4 bytes */
+	ath9k_hw_filltxdesc(ah, ds, roundup(skb->len, 4),
+			    true, true, ds);
+
+	memset(series, 0, sizeof(struct ath9k_11n_rate_series) * 4);
+	series[0].Tries = 1;
+	series[0].Rate = rate;
+	series[0].ChSel = sc->tx_chainmask;
+	series[0].RateFlags = (ctsrate) ? ATH9K_RATESERIES_RTS_CTS : 0;
+	ath9k_hw_set11n_ratescenario(ah, ds, ds, 0, ctsrate, ctsduration,
+				     series, 4, 0);
+}
+
+static struct ath_buf *ath_beacon_generate(struct ieee80211_hw *hw,
+					   struct ieee80211_vif *vif)
+{
+	struct ath_wiphy *aphy = hw->priv;
+	struct ath_softc *sc = aphy->sc;
+	struct ath_buf *bf;
+	struct ath_vif *avp;
+	struct sk_buff *skb;
+	struct ath_txq *cabq;
+	struct ieee80211_tx_info *info;
+	int cabq_depth;
+
+	if (aphy->state != ATH_WIPHY_ACTIVE)
+		return NULL;
+
+	avp = (void *)vif->drv_priv;
+	cabq = sc->beacon.cabq;
+
+	if (avp->av_bcbuf == NULL)
+		return NULL;
+
+	/* Release the old beacon first */
+
+	bf = avp->av_bcbuf;
+	skb = bf->bf_mpdu;
+	if (skb) {
+		dma_unmap_single(sc->dev, bf->bf_dmacontext,
+				 skb->len, DMA_TO_DEVICE);
+		dev_kfree_skb_any(skb);
+	}
+
+	/* Get a new beacon from mac80211 */
+
+	skb = ieee80211_beacon_get(hw, vif);
+	bf->bf_mpdu = skb;
+	if (skb == NULL)
+		return NULL;
+	((struct ieee80211_mgmt *)skb->data)->u.beacon.timestamp =
+		avp->tsf_adjust;
+
+	info = IEEE80211_SKB_CB(skb);
+	if (info->flags & IEEE80211_TX_CTL_ASSIGN_SEQ) {
+		/*
+		 * TODO: make sure the seq# gets assigned properly (vs. other
+		 * TX frames)
+		 */
+		struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+		sc->tx.seq_no += 0x10;
+		hdr->seq_ctrl &= cpu_to_le16(IEEE80211_SCTL_FRAG);
+		hdr->seq_ctrl |= cpu_to_le16(sc->tx.seq_no);
+	}
+
+	bf->bf_buf_addr = bf->bf_dmacontext =
+		dma_map_single(sc->dev, skb->data,
+			       skb->len, DMA_TO_DEVICE);
+	if (unlikely(dma_mapping_error(sc->dev, bf->bf_buf_addr))) {
+		dev_kfree_skb_any(skb);
+		bf->bf_mpdu = NULL;
+		DPRINTF(sc, ATH_DBG_FATAL, "dma_mapping_error on beaconing\n");
+		return NULL;
+	}
+
+	skb = ieee80211_get_buffered_bc(hw, vif);
+
+	/*
+	 * if the CABQ traffic from previous DTIM is pending and the current
+	 *  beacon is also a DTIM.
+	 *  1) if there is only one vif let the cab traffic continue.
+	 *  2) if there are more than one vif and we are using staggered
+	 *     beacons, then drain the cabq by dropping all the frames in
+	 *     the cabq so that the current vifs cab traffic can be scheduled.
+	 */
+	spin_lock_bh(&cabq->axq_lock);
+	cabq_depth = cabq->axq_depth;
+	spin_unlock_bh(&cabq->axq_lock);
+
+	if (skb && cabq_depth) {
+		if (sc->nvifs > 1) {
+			DPRINTF(sc, ATH_DBG_BEACON,
+				"Flushing previous cabq traffic\n");
+			ath_draintxq(sc, cabq, false);
+		}
+	}
+
+	ath_beacon_setup(sc, avp, bf);
+
+	while (skb) {
+		ath_tx_cabq(hw, skb);
+		skb = ieee80211_get_buffered_bc(hw, vif);
+	}
+
+	return bf;
+}
+
+/*
+ * Startup beacon transmission for adhoc mode when they are sent entirely
+ * by the hardware using the self-linked descriptor + veol trick.
+*/
+static void ath_beacon_start_adhoc(struct ath_softc *sc,
+				   struct ieee80211_vif *vif)
+{
+	struct ath_hw *ah = sc->sc_ah;
+	struct ath_buf *bf;
+	struct ath_vif *avp;
+	struct sk_buff *skb;
+
+	avp = (void *)vif->drv_priv;
+
+	if (avp->av_bcbuf == NULL)
+		return;
+
+	bf = avp->av_bcbuf;
+	skb = bf->bf_mpdu;
+
+	ath_beacon_setup(sc, avp, bf);
+
+	/* NB: caller is known to have already stopped tx dma */
+	ath9k_hw_puttxbuf(ah, sc->beacon.beaconq, bf->bf_daddr);
+	ath9k_hw_txstart(ah, sc->beacon.beaconq);
+	DPRINTF(sc, ATH_DBG_BEACON, "TXDP%u = %llx (%p)\n",
+		sc->beacon.beaconq, ito64(bf->bf_daddr), bf->bf_desc);
+}
+
+int ath_beaconq_setup(struct ath_hw *ah)
+{
+	struct ath9k_tx_queue_info qi;
+
+	memset(&qi, 0, sizeof(qi));
+	qi.tqi_aifs = 1;
+	qi.tqi_cwmin = 0;
+	qi.tqi_cwmax = 0;
+	/* NB: don't enable any interrupts */
+	return ath9k_hw_setuptxqueue(ah, ATH9K_TX_QUEUE_BEACON, &qi);
+}
+
+int ath_beacon_alloc(struct ath_wiphy *aphy, struct ieee80211_vif *vif)
+{
+	struct ath_softc *sc = aphy->sc;
+	struct ath_vif *avp;
+	struct ath_buf *bf;
+	struct sk_buff *skb;
+	__le64 tstamp;
+
+	avp = (void *)vif->drv_priv;
+
+	/* Allocate a beacon descriptor if we haven't done so. */
+	if (!avp->av_bcbuf) {
+		/* Allocate beacon state for hostap/ibss.  We know
+		 * a buffer is available. */
+		avp->av_bcbuf = list_first_entry(&sc->beacon.bbuf,
+						 struct ath_buf, list);
+		list_del(&avp->av_bcbuf->list);
+
+		if (sc->sc_ah->opmode == NL80211_IFTYPE_AP ||
+		    !(sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_VEOL)) {
+			int slot;
+			/*
+			 * Assign the vif to a beacon xmit slot. As
+			 * above, this cannot fail to find one.
+			 */
+			avp->av_bslot = 0;
+			for (slot = 0; slot < ATH_BCBUF; slot++)
+				if (sc->beacon.bslot[slot] == NULL) {
+					/*
+					 * XXX hack, space out slots to better
+					 * deal with misses
+					 */
+					if (slot+1 < ATH_BCBUF &&
+					    sc->beacon.bslot[slot+1] == NULL) {
+						avp->av_bslot = slot+1;
+						break;
+					}
+					avp->av_bslot = slot;
+					/* NB: keep looking for a double slot */
+				}
+			BUG_ON(sc->beacon.bslot[avp->av_bslot] != NULL);
+			sc->beacon.bslot[avp->av_bslot] = vif;
+			sc->beacon.bslot_aphy[avp->av_bslot] = aphy;
+			sc->nbcnvifs++;
+		}
+	}
+
+	/* release the previous beacon frame, if it already exists. */
+	bf = avp->av_bcbuf;
+	if (bf->bf_mpdu != NULL) {
+		skb = bf->bf_mpdu;
+		dma_unmap_single(sc->dev, bf->bf_dmacontext,
+				 skb->len, DMA_TO_DEVICE);
+		dev_kfree_skb_any(skb);
+		bf->bf_mpdu = NULL;
+	}
+
+	/* NB: the beacon data buffer must be 32-bit aligned. */
+	skb = ieee80211_beacon_get(sc->hw, vif);
+	if (skb == NULL) {
+		DPRINTF(sc, ATH_DBG_BEACON, "cannot get skb\n");
+		return -ENOMEM;
+	}
+
+	tstamp = ((struct ieee80211_mgmt *)skb->data)->u.beacon.timestamp;
+	sc->beacon.bc_tstamp = le64_to_cpu(tstamp);
+	/* Calculate a TSF adjustment factor required for staggered beacons. */
+	if (avp->av_bslot > 0) {
+		u64 tsfadjust;
+		int intval;
+
+		intval = sc->hw->conf.beacon_int ?
+			sc->hw->conf.beacon_int : ATH_DEFAULT_BINTVAL;
+
+		/*
+		 * Calculate the TSF offset for this beacon slot, i.e., the
+		 * number of usecs that need to be added to the timestamp field
+		 * in Beacon and Probe Response frames. Beacon slot 0 is
+		 * processed at the correct offset, so it does not require TSF
+		 * adjustment. Other slots are adjusted to get the timestamp
+		 * close to the TBTT for the BSS.
+		 */
+		tsfadjust = intval * avp->av_bslot / ATH_BCBUF;
+		avp->tsf_adjust = cpu_to_le64(TU_TO_USEC(tsfadjust));
+
+		DPRINTF(sc, ATH_DBG_BEACON,
+			"stagger beacons, bslot %d intval %u tsfadjust %llu\n",
+			avp->av_bslot, intval, (unsigned long long)tsfadjust);
+
+		((struct ieee80211_mgmt *)skb->data)->u.beacon.timestamp =
+			avp->tsf_adjust;
+	} else
+		avp->tsf_adjust = cpu_to_le64(0);
+
+	bf->bf_mpdu = skb;
+	bf->bf_buf_addr = bf->bf_dmacontext =
+		dma_map_single(sc->dev, skb->data,
+			       skb->len, DMA_TO_DEVICE);
+	if (unlikely(dma_mapping_error(sc->dev, bf->bf_buf_addr))) {
+		dev_kfree_skb_any(skb);
+		bf->bf_mpdu = NULL;
+		DPRINTF(sc, ATH_DBG_FATAL,
+			"dma_mapping_error on beacon alloc\n");
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+void ath_beacon_return(struct ath_softc *sc, struct ath_vif *avp)
+{
+	if (avp->av_bcbuf != NULL) {
+		struct ath_buf *bf;
+
+		if (avp->av_bslot != -1) {
+			sc->beacon.bslot[avp->av_bslot] = NULL;
+			sc->beacon.bslot_aphy[avp->av_bslot] = NULL;
+			sc->nbcnvifs--;
+		}
+
+		bf = avp->av_bcbuf;
+		if (bf->bf_mpdu != NULL) {
+			struct sk_buff *skb = bf->bf_mpdu;
+			dma_unmap_single(sc->dev, bf->bf_dmacontext,
+					 skb->len, DMA_TO_DEVICE);
+			dev_kfree_skb_any(skb);
+			bf->bf_mpdu = NULL;
+		}
+		list_add_tail(&bf->list, &sc->beacon.bbuf);
+
+		avp->av_bcbuf = NULL;
+	}
+}
+
+void ath_beacon_tasklet(unsigned long data)
+{
+	struct ath_softc *sc = (struct ath_softc *)data;
+	struct ath_hw *ah = sc->sc_ah;
+	struct ath_buf *bf = NULL;
+	struct ieee80211_vif *vif;
+	struct ath_wiphy *aphy;
+	int slot;
+	u32 bfaddr, bc = 0, tsftu;
+	u64 tsf;
+	u16 intval;
+
+	/*
+	 * Check if the previous beacon has gone out.  If
+	 * not don't try to post another, skip this period
+	 * and wait for the next.  Missed beacons indicate
+	 * a problem and should not occur.  If we miss too
+	 * many consecutive beacons reset the device.
+	 */
+	if (ath9k_hw_numtxpending(ah, sc->beacon.beaconq) != 0) {
+		sc->beacon.bmisscnt++;
+
+		if (sc->beacon.bmisscnt < BSTUCK_THRESH) {
+			DPRINTF(sc, ATH_DBG_BEACON,
+				"missed %u consecutive beacons\n",
+				sc->beacon.bmisscnt);
+		} else if (sc->beacon.bmisscnt >= BSTUCK_THRESH) {
+			DPRINTF(sc, ATH_DBG_BEACON,
+				"beacon is officially stuck\n");
+			ath_reset(sc, false);
+		}
+
+		return;
+	}
+
+	if (sc->beacon.bmisscnt != 0) {
+		DPRINTF(sc, ATH_DBG_BEACON,
+			"resume beacon xmit after %u misses\n",
+			sc->beacon.bmisscnt);
+		sc->beacon.bmisscnt = 0;
+	}
+
+	/*
+	 * Generate beacon frames. we are sending frames
+	 * staggered so calculate the slot for this frame based
+	 * on the tsf to safeguard against missing an swba.
+	 */
+
+	intval = sc->hw->conf.beacon_int ?
+		sc->hw->conf.beacon_int : ATH_DEFAULT_BINTVAL;
+
+	tsf = ath9k_hw_gettsf64(ah);
+	tsftu = TSF_TO_TU(tsf>>32, tsf);
+	slot = ((tsftu % intval) * ATH_BCBUF) / intval;
+	/*
+	 * Reverse the slot order to get slot 0 on the TBTT offset that does
+	 * not require TSF adjustment and other slots adding
+	 * slot/ATH_BCBUF * beacon_int to timestamp. For example, with
+	 * ATH_BCBUF = 4, we process beacon slots as follows: 3 2 1 0 3 2 1 ..
+	 * and slot 0 is at correct offset to TBTT.
+	 */
+	slot = ATH_BCBUF - slot - 1;
+	vif = sc->beacon.bslot[slot];
+	aphy = sc->beacon.bslot_aphy[slot];
+
+	DPRINTF(sc, ATH_DBG_BEACON,
+		"slot %d [tsf %llu tsftu %u intval %u] vif %p\n",
+		slot, tsf, tsftu, intval, vif);
+
+	bfaddr = 0;
+	if (vif) {
+		bf = ath_beacon_generate(aphy->hw, vif);
+		if (bf != NULL) {
+			bfaddr = bf->bf_daddr;
+			bc = 1;
+		}
+	}
+
+	/*
+	 * Handle slot time change when a non-ERP station joins/leaves
+	 * an 11g network.  The 802.11 layer notifies us via callback,
+	 * we mark updateslot, then wait one beacon before effecting
+	 * the change.  This gives associated stations at least one
+	 * beacon interval to note the state change.
+	 *
+	 * NB: The slot time change state machine is clocked according
+	 *     to whether we are bursting or staggering beacons.  We
+	 *     recognize the request to update and record the current
+	 *     slot then don't transition until that slot is reached
+	 *     again.  If we miss a beacon for that slot then we'll be
+	 *     slow to transition but we'll be sure at least one beacon
+	 *     interval has passed.  When bursting slot is always left
+	 *     set to ATH_BCBUF so this check is a noop.
+	 */
+	if (sc->beacon.updateslot == UPDATE) {
+		sc->beacon.updateslot = COMMIT; /* commit next beacon */
+		sc->beacon.slotupdate = slot;
+	} else if (sc->beacon.updateslot == COMMIT && sc->beacon.slotupdate == slot) {
+		ath9k_hw_setslottime(sc->sc_ah, sc->beacon.slottime);
+		sc->beacon.updateslot = OK;
+	}
+	if (bfaddr != 0) {
+		/*
+		 * Stop any current dma and put the new frame(s) on the queue.
+		 * This should never fail since we check above that no frames
+		 * are still pending on the queue.
+		 */
+		if (!ath9k_hw_stoptxdma(ah, sc->beacon.beaconq)) {
+			DPRINTF(sc, ATH_DBG_FATAL,
+				"beacon queue %u did not stop?\n", sc->beacon.beaconq);
+		}
+
+		/* NB: cabq traffic should already be queued and primed */
+		ath9k_hw_puttxbuf(ah, sc->beacon.beaconq, bfaddr);
+		ath9k_hw_txstart(ah, sc->beacon.beaconq);
+
+		sc->beacon.ast_be_xmit += bc;     /* XXX per-vif? */
+	}
+}
+
+/*
+ * For multi-bss ap support beacons are either staggered evenly over N slots or
+ * burst together.  For the former arrange for the SWBA to be delivered for each
+ * slot. Slots that are not occupied will generate nothing.
+ */
+static void ath_beacon_config_ap(struct ath_softc *sc,
+				 struct ath_beacon_config *conf,
+				 struct ath_vif *avp)
+{
+	u32 nexttbtt, intval;
+
+	/* Configure the timers only when the TSF has to be reset */
+
+	if (!(sc->sc_flags & SC_OP_TSF_RESET))
+		return;
+
+	/* NB: the beacon interval is kept internally in TU's */
+	intval = conf->beacon_interval & ATH9K_BEACON_PERIOD;
+	intval /= ATH_BCBUF;    /* for staggered beacons */
+	nexttbtt = intval;
+	intval |= ATH9K_BEACON_RESET_TSF;
+
+	/*
+	 * In AP mode we enable the beacon timers and SWBA interrupts to
+	 * prepare beacon frames.
+	 */
+	intval |= ATH9K_BEACON_ENA;
+	sc->imask |= ATH9K_INT_SWBA;
+	ath_beaconq_config(sc);
+
+	/* Set the computed AP beacon timers */
+
+	ath9k_hw_set_interrupts(sc->sc_ah, 0);
+	ath9k_hw_beaconinit(sc->sc_ah, nexttbtt, intval);
+	sc->beacon.bmisscnt = 0;
+	ath9k_hw_set_interrupts(sc->sc_ah, sc->imask);
+
+	/* Clear the reset TSF flag, so that subsequent beacon updation
+	   will not reset the HW TSF. */
+
+	sc->sc_flags &= ~SC_OP_TSF_RESET;
+}
+
+/*
+ * This sets up the beacon timers according to the timestamp of the last
+ * received beacon and the current TSF, configures PCF and DTIM
+ * handling, programs the sleep registers so the hardware will wakeup in
+ * time to receive beacons, and configures the beacon miss handling so
+ * we'll receive a BMISS interrupt when we stop seeing beacons from the AP
+ * we've associated with.
+ */
+static void ath_beacon_config_sta(struct ath_softc *sc,
+				  struct ath_beacon_config *conf,
+				  struct ath_vif *avp)
+{
+	struct ath9k_beacon_state bs;
+	int dtimperiod, dtimcount, sleepduration;
+	int cfpperiod, cfpcount;
+	u32 nexttbtt = 0, intval, tsftu;
+	u64 tsf;
+
+	memset(&bs, 0, sizeof(bs));
+	intval = conf->beacon_interval & ATH9K_BEACON_PERIOD;
+
+	/*
+	 * Setup dtim and cfp parameters according to
+	 * last beacon we received (which may be none).
+	 */
+	dtimperiod = conf->dtim_period;
+	if (dtimperiod <= 0)		/* NB: 0 if not known */
+		dtimperiod = 1;
+	dtimcount = conf->dtim_count;
+	if (dtimcount >= dtimperiod)	/* NB: sanity check */
+		dtimcount = 0;
+	cfpperiod = 1;			/* NB: no PCF support yet */
+	cfpcount = 0;
+
+	sleepduration = conf->listen_interval * intval;
+	if (sleepduration <= 0)
+		sleepduration = intval;
+
+	/*
+	 * Pull nexttbtt forward to reflect the current
+	 * TSF and calculate dtim+cfp state for the result.
+	 */
+	tsf = ath9k_hw_gettsf64(sc->sc_ah);
+	tsftu = TSF_TO_TU(tsf>>32, tsf) + FUDGE;
+	do {
+		nexttbtt += intval;
+		if (--dtimcount < 0) {
+			dtimcount = dtimperiod - 1;
+			if (--cfpcount < 0)
+				cfpcount = cfpperiod - 1;
+		}
+	} while (nexttbtt < tsftu);
+
+	bs.bs_intval = intval;
+	bs.bs_nexttbtt = nexttbtt;
+	bs.bs_dtimperiod = dtimperiod*intval;
+	bs.bs_nextdtim = bs.bs_nexttbtt + dtimcount*intval;
+	bs.bs_cfpperiod = cfpperiod*bs.bs_dtimperiod;
+	bs.bs_cfpnext = bs.bs_nextdtim + cfpcount*bs.bs_dtimperiod;
+	bs.bs_cfpmaxduration = 0;
+
+	/*
+	 * Calculate the number of consecutive beacons to miss* before taking
+	 * a BMISS interrupt. The configuration is specified in TU so we only
+	 * need calculate based	on the beacon interval.  Note that we clamp the
+	 * result to at most 15 beacons.
+	 */
+	if (sleepduration > intval) {
+		bs.bs_bmissthreshold = conf->listen_interval *
+			ATH_DEFAULT_BMISS_LIMIT / 2;
+	} else {
+		bs.bs_bmissthreshold = DIV_ROUND_UP(conf->bmiss_timeout, intval);
+		if (bs.bs_bmissthreshold > 15)
+			bs.bs_bmissthreshold = 15;
+		else if (bs.bs_bmissthreshold <= 0)
+			bs.bs_bmissthreshold = 1;
+	}
+
+	/*
+	 * Calculate sleep duration. The configuration is given in ms.
+	 * We ensure a multiple of the beacon period is used. Also, if the sleep
+	 * duration is greater than the DTIM period then it makes senses
+	 * to make it a multiple of that.
+	 *
+	 * XXX fixed at 100ms
+	 */
+
+	bs.bs_sleepduration = roundup(IEEE80211_MS_TO_TU(100), sleepduration);
+	if (bs.bs_sleepduration > bs.bs_dtimperiod)
+		bs.bs_sleepduration = bs.bs_dtimperiod;
+
+	/* TSF out of range threshold fixed at 1 second */
+	bs.bs_tsfoor_threshold = ATH9K_TSFOOR_THRESHOLD;
+
+	DPRINTF(sc, ATH_DBG_BEACON, "tsf: %llu tsftu: %u\n", tsf, tsftu);
+	DPRINTF(sc, ATH_DBG_BEACON,
+		"bmiss: %u sleep: %u cfp-period: %u maxdur: %u next: %u\n",
+		bs.bs_bmissthreshold, bs.bs_sleepduration,
+		bs.bs_cfpperiod, bs.bs_cfpmaxduration, bs.bs_cfpnext);
+
+	/* Set the computed STA beacon timers */
+
+	ath9k_hw_set_interrupts(sc->sc_ah, 0);
+	ath9k_hw_set_sta_beacon_timers(sc->sc_ah, &bs);
+	sc->imask |= ATH9K_INT_BMISS;
+	ath9k_hw_set_interrupts(sc->sc_ah, sc->imask);
+}
+
+static void ath_beacon_config_adhoc(struct ath_softc *sc,
+				    struct ath_beacon_config *conf,
+				    struct ath_vif *avp,
+				    struct ieee80211_vif *vif)
+{
+	u64 tsf;
+	u32 tsftu, intval, nexttbtt;
+
+	intval = conf->beacon_interval & ATH9K_BEACON_PERIOD;
+
+	/* Pull nexttbtt forward to reflect the current TSF */
+
+	nexttbtt = TSF_TO_TU(sc->beacon.bc_tstamp >> 32, sc->beacon.bc_tstamp);
+	if (nexttbtt == 0)
+                nexttbtt = intval;
+        else if (intval)
+                nexttbtt = roundup(nexttbtt, intval);
+
+	tsf = ath9k_hw_gettsf64(sc->sc_ah);
+	tsftu = TSF_TO_TU((u32)(tsf>>32), (u32)tsf) + FUDGE;
+	do {
+		nexttbtt += intval;
+	} while (nexttbtt < tsftu);
+
+	DPRINTF(sc, ATH_DBG_BEACON,
+		"IBSS nexttbtt %u intval %u (%u)\n",
+		nexttbtt, intval, conf->beacon_interval);
+
+	/*
+	 * 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.
+	 */
+	intval |= ATH9K_BEACON_ENA;
+	if (!(sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_VEOL))
+		sc->imask |= ATH9K_INT_SWBA;
+
+	ath_beaconq_config(sc);
+
+	/* Set the computed ADHOC beacon timers */
+
+	ath9k_hw_set_interrupts(sc->sc_ah, 0);
+	ath9k_hw_beaconinit(sc->sc_ah, nexttbtt, intval);
+	sc->beacon.bmisscnt = 0;
+	ath9k_hw_set_interrupts(sc->sc_ah, sc->imask);
+
+	if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_VEOL)
+		ath_beacon_start_adhoc(sc, vif);
+}
+
+void ath_beacon_config(struct ath_softc *sc, struct ieee80211_vif *vif)
+{
+	struct ath_beacon_config conf;
+
+	/* Setup the beacon configuration parameters */
+
+	memset(&conf, 0, sizeof(struct ath_beacon_config));
+	conf.beacon_interval = sc->hw->conf.beacon_int ?
+		sc->hw->conf.beacon_int : ATH_DEFAULT_BINTVAL;
+	conf.listen_interval = 1;
+	conf.dtim_period = conf.beacon_interval;
+	conf.dtim_count = 1;
+	conf.bmiss_timeout = ATH_DEFAULT_BMISS_LIMIT * conf.beacon_interval;
+
+	if (vif) {
+		struct ath_vif *avp = (struct ath_vif *)vif->drv_priv;
+
+		switch(avp->av_opmode) {
+		case NL80211_IFTYPE_AP:
+			ath_beacon_config_ap(sc, &conf, avp);
+			break;
+		case NL80211_IFTYPE_ADHOC:
+		case NL80211_IFTYPE_MESH_POINT:
+			ath_beacon_config_adhoc(sc, &conf, avp, vif);
+			break;
+		case NL80211_IFTYPE_STATION:
+			ath_beacon_config_sta(sc, &conf, avp);
+			break;
+		default:
+			DPRINTF(sc, ATH_DBG_CONFIG,
+				"Unsupported beaconing mode\n");
+			return;
+		}
+
+		sc->sc_flags |= SC_OP_BEACONS;
+	}
+}