drivers/net/wireless/ath/ath9k/beacon.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (c) 2008-2011 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 <linux/dma-mapping.h>
 #include "ath9k.h"

 #define FUDGE 2

 static void ath9k_reset_beacon_status(struct ath_softc *sc)
 {
 	sc->beacon.tx_processed = false;
 	sc->beacon.tx_last = false;
 }

 /*
  *  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 void ath9k_beaconq_config(struct ath_softc *sc)
 {
 	struct ath_hw *ah = sc->sc_ah;
 	struct ath_common *common = ath9k_hw_common(ah);
 	struct ath9k_tx_queue_info qi, qi_be;
 	struct ath_txq *txq;

 	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. */
 		txq = sc->tx.txq_map[IEEE80211_AC_BE];
 		ath9k_hw_get_txq_props(ah, txq->axq_qnum, &qi_be);
 		qi.tqi_aifs = qi_be.tqi_aifs;
 		if (ah->slottime == ATH9K_SLOT_TIME_20)
 			qi.tqi_cwmin = 2*qi_be.tqi_cwmin;
 		else
 			qi.tqi_cwmin = 4*qi_be.tqi_cwmin;
 		qi.tqi_cwmax = qi_be.tqi_cwmax;
 	}

 	if (!ath9k_hw_set_txq_props(ah, sc->beacon.beaconq, &qi)) {
 		ath_err(common, "Unable to update h/w beacon queue parameters\n");
 	} else {
 		ath9k_hw_resettxqueue(ah, sc->beacon.beaconq);
 	}
 }

 /*
  *  Associates the beacon frame buffer with a transmit descriptor.  Will set
  *  up rate codes, and channel flags. Beacons are always sent out at the
  *  lowest rate, and are not retried.
 */
 static void ath9k_beacon_setup(struct ath_softc *sc, struct ieee80211_vif *vif,
 			     struct ath_buf *bf, int rateidx)
 {
 	struct sk_buff *skb = bf->bf_mpdu;
 	struct ath_hw *ah = sc->sc_ah;
 	struct ath_common *common = ath9k_hw_common(ah);
 	struct ath_tx_info info;
 	struct ieee80211_supported_band *sband;
 	u8 chainmask = ah->txchainmask;
 	u8 rate = 0;

 	sband = &sc->sbands[common->hw->conf.channel->band];
 	rate = sband->bitrates[rateidx].hw_value;
 	if (vif->bss_conf.use_short_preamble)
 		rate |= sband->bitrates[rateidx].hw_value_short;

 	memset(&info, 0, sizeof(info));
 	info.pkt_len = skb->len + FCS_LEN;
 	info.type = ATH9K_PKT_TYPE_BEACON;
 	info.txpower = MAX_RATE_POWER;
 	info.keyix = ATH9K_TXKEYIX_INVALID;
 	info.keytype = ATH9K_KEY_TYPE_CLEAR;
 	info.flags = ATH9K_TXDESC_NOACK | ATH9K_TXDESC_CLRDMASK;

 	info.buf_addr[0] = bf->bf_buf_addr;
 	info.buf_len[0] = roundup(skb->len, 4);

 	info.is_first = true;
 	info.is_last = true;

 	info.qcu = sc->beacon.beaconq;

 	info.rates[0].Tries = 1;
 	info.rates[0].Rate = rate;
 	info.rates[0].ChSel = ath_txchainmask_reduction(sc, chainmask, rate);

 	ath9k_hw_set_txdesc(ah, bf->bf_desc, &info);
 }

 static void ath9k_tx_cabq(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct ath_softc *sc = hw->priv;
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
 	struct ath_tx_control txctl;

 	memset(&txctl, 0, sizeof(struct ath_tx_control));
 	txctl.txq = sc->beacon.cabq;

 	ath_dbg(common, XMIT, "transmitting CABQ packet, skb: %p\n", skb);

 	if (ath_tx_start(hw, skb, &txctl) != 0) {
 		ath_dbg(common, XMIT, "CABQ TX failed\n");
 		ieee80211_free_txskb(hw, skb);
 	}
 }

 static struct ath_buf *ath9k_beacon_generate(struct ieee80211_hw *hw,
 					     struct ieee80211_vif *vif)
 {
 	struct ath_softc *sc = hw->priv;
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
 	struct ath_buf *bf;
 	struct ath_vif *avp = (void *)vif->drv_priv;
 	struct sk_buff *skb;
 	struct ath_txq *cabq = sc->beacon.cabq;
 	struct ieee80211_tx_info *info;
 	struct ieee80211_mgmt *mgmt_hdr;
 	int cabq_depth;

 	if (avp->av_bcbuf == NULL)
 		return NULL;

 	bf = avp->av_bcbuf;
 	skb = bf->bf_mpdu;
 	if (skb) {
 		dma_unmap_single(sc->dev, bf->bf_buf_addr,
 				 skb->len, DMA_TO_DEVICE);
 		dev_kfree_skb_any(skb);
 		bf->bf_buf_addr = 0;
 		bf->bf_mpdu = NULL;
 	}

 	skb = ieee80211_beacon_get(hw, vif);
 	if (skb == NULL)
 		return NULL;

 	bf->bf_mpdu = skb;

 	mgmt_hdr = (struct ieee80211_mgmt *)skb->data;
 	mgmt_hdr->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 = 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;
 		bf->bf_buf_addr = 0;
 		ath_err(common, "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) {
 			ath_dbg(common, BEACON,
 				"Flushing previous cabq traffic\n");
 			ath_draintxq(sc, cabq, false);
 		}
 	}

 	ath9k_beacon_setup(sc, vif, bf, info->control.rates[0].idx);

 	while (skb) {
 		ath9k_tx_cabq(hw, skb);
 		skb = ieee80211_get_buffered_bc(hw, vif);
 	}

 	return bf;
 }

 void ath9k_beacon_assign_slot(struct ath_softc *sc, struct ieee80211_vif *vif)
 {
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
 	struct ath_vif *avp = (void *)vif->drv_priv;
 	int slot;

 	avp->av_bcbuf = list_first_entry(&sc->beacon.bbuf, struct ath_buf, list);
 	list_del(&avp->av_bcbuf->list);

 	for (slot = 0; slot < ATH_BCBUF; slot++) {
 		if (sc->beacon.bslot[slot] == NULL) {
 			avp->av_bslot = slot;
 			break;
 		}
 	}

 	sc->beacon.bslot[avp->av_bslot] = vif;
 	sc->nbcnvifs++;

 	ath_dbg(common, CONFIG, "Added interface at beacon slot: %d\n",
 		avp->av_bslot);
 }

 void ath9k_beacon_remove_slot(struct ath_softc *sc, struct ieee80211_vif *vif)
 {
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
 	struct ath_vif *avp = (void *)vif->drv_priv;
 	struct ath_buf *bf = avp->av_bcbuf;

 	ath_dbg(common, CONFIG, "Removing interface at beacon slot: %d\n",
 		avp->av_bslot);

 	tasklet_disable(&sc->bcon_tasklet);

 	if (bf && bf->bf_mpdu) {
 		struct sk_buff *skb = bf->bf_mpdu;
 		dma_unmap_single(sc->dev, bf->bf_buf_addr,
 				 skb->len, DMA_TO_DEVICE);
 		dev_kfree_skb_any(skb);
 		bf->bf_mpdu = NULL;
 		bf->bf_buf_addr = 0;
 	}

 	avp->av_bcbuf = NULL;
 	sc->beacon.bslot[avp->av_bslot] = NULL;
 	sc->nbcnvifs--;
 	list_add_tail(&bf->list, &sc->beacon.bbuf);

 	tasklet_enable(&sc->bcon_tasklet);
 }

 static int ath9k_beacon_choose_slot(struct ath_softc *sc)
 {
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
 	struct ath_beacon_config *cur_conf = &sc->cur_beacon_conf;
 	u16 intval;
 	u32 tsftu;
 	u64 tsf;
 	int slot;

 	if (sc->sc_ah->opmode != NL80211_IFTYPE_AP) {
 		ath_dbg(common, BEACON, "slot 0, tsf: %llu\n",
 			ath9k_hw_gettsf64(sc->sc_ah));
 		return 0;
 	}

 	intval = cur_conf->beacon_interval ? : ATH_DEFAULT_BINTVAL;
 	tsf = ath9k_hw_gettsf64(sc->sc_ah);
 	tsf += TU_TO_USEC(sc->sc_ah->config.sw_beacon_response_time);
 	tsftu = TSF_TO_TU((tsf * ATH_BCBUF) >>32, tsf * ATH_BCBUF);
 	slot = (tsftu % (intval * ATH_BCBUF)) / intval;

 	ath_dbg(common, BEACON, "slot: %d tsf: %llu tsftu: %u\n",
 		slot, tsf, tsftu / ATH_BCBUF);

 	return slot;
 }

 void ath9k_set_tsfadjust(struct ath_softc *sc, struct ieee80211_vif *vif)
 {
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
 	struct ath_beacon_config *cur_conf = &sc->cur_beacon_conf;
 	struct ath_vif *avp = (void *)vif->drv_priv;
 	u64 tsfadjust;

 	if (avp->av_bslot == 0)
 		return;

 	tsfadjust = cur_conf->beacon_interval * avp->av_bslot / ATH_BCBUF;
 	avp->tsf_adjust = cpu_to_le64(TU_TO_USEC(tsfadjust));

 	ath_dbg(common, CONFIG, "tsfadjust is: %llu for bslot: %d\n",
 		(unsigned long long)tsfadjust, avp->av_bslot);
 }

 void ath9k_beacon_tasklet(unsigned long data)
 {
 	struct ath_softc *sc = (struct ath_softc *)data;
 	struct ath_hw *ah = sc->sc_ah;
 	struct ath_common *common = ath9k_hw_common(ah);
 	struct ath_buf *bf = NULL;
 	struct ieee80211_vif *vif;
 	bool edma = !!(ah->caps.hw_caps & ATH9K_HW_CAP_EDMA);
 	int slot;

 	if (test_bit(SC_OP_HW_RESET, &sc->sc_flags)) {
 		ath_dbg(common, RESET,
 			"reset work is pending, skip beaconing now\n");
 		return;
 	}

 	/*
 	 * 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 (!ath9k_hw_check_alive(ah))
 			ieee80211_queue_work(sc->hw, &sc->hw_check_work);

 		if (sc->beacon.bmisscnt < BSTUCK_THRESH * sc->nbcnvifs) {
 			ath_dbg(common, BSTUCK,
 				"missed %u consecutive beacons\n",
 				sc->beacon.bmisscnt);
 			ath9k_hw_stop_dma_queue(ah, sc->beacon.beaconq);
 			if (sc->beacon.bmisscnt > 3)
 				ath9k_hw_bstuck_nfcal(ah);
 		} else if (sc->beacon.bmisscnt >= BSTUCK_THRESH) {
 			ath_dbg(common, BSTUCK, "beacon is officially stuck\n");
 			sc->beacon.bmisscnt = 0;
 			ath9k_queue_reset(sc, RESET_TYPE_BEACON_STUCK);
 		}

 		return;
 	}

 	slot = ath9k_beacon_choose_slot(sc);
 	vif = sc->beacon.bslot[slot];

 	if (!vif || !vif->bss_conf.enable_beacon)
 		return;

 	bf = ath9k_beacon_generate(sc->hw, vif);

 	if (sc->beacon.bmisscnt != 0) {
 		ath_dbg(common, BSTUCK, "resume beacon xmit after %u misses\n",
 			sc->beacon.bmisscnt);
 		sc->beacon.bmisscnt = 0;
 	}

 	/*
 	 * 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;
 		sc->beacon.slotupdate = slot;
 	} else if (sc->beacon.updateslot == COMMIT &&
 		   sc->beacon.slotupdate == slot) {
 		ah->slottime = sc->beacon.slottime;
 		ath9k_hw_init_global_settings(ah);
 		sc->beacon.updateslot = OK;
 	}

 	if (bf) {
 		ath9k_reset_beacon_status(sc);

 		ath_dbg(common, BEACON,
 			"Transmitting beacon for slot: %d\n", slot);

 		/* NB: cabq traffic should already be queued and primed */
 		ath9k_hw_puttxbuf(ah, sc->beacon.beaconq, bf->bf_daddr);

 		if (!edma)
 			ath9k_hw_txstart(ah, sc->beacon.beaconq);
 	}
 }

 static void ath9k_beacon_init(struct ath_softc *sc, u32 nexttbtt, u32 intval)
 {
 	struct ath_hw *ah = sc->sc_ah;

 	ath9k_hw_disable_interrupts(ah);
 	ath9k_hw_reset_tsf(ah);
 	ath9k_beaconq_config(sc);
 	ath9k_hw_beaconinit(ah, nexttbtt, intval);
 	sc->beacon.bmisscnt = 0;
 	ath9k_hw_set_interrupts(ah);
 	ath9k_hw_enable_interrupts(ah);
 }

 /*
  * 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 ath9k_beacon_config_ap(struct ath_softc *sc,
 				   struct ath_beacon_config *conf)
 {
 	struct ath_hw *ah = sc->sc_ah;
 	struct ath_common *common = ath9k_hw_common(ah);
 	u32 nexttbtt, intval;

 	/* NB: the beacon interval is kept internally in TU's */
 	intval = TU_TO_USEC(conf->beacon_interval);
 	intval /= ATH_BCBUF;
 	nexttbtt = intval;

 	if (conf->enable_beacon)
 		ah->imask |= ATH9K_INT_SWBA;
 	else
 		ah->imask &= ~ATH9K_INT_SWBA;

 	ath_dbg(common, BEACON, "AP nexttbtt: %u intval: %u conf_intval: %u\n",
 		nexttbtt, intval, conf->beacon_interval);

 	ath9k_beacon_init(sc, nexttbtt, intval);
 }

 /*
  * 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 ath9k_beacon_config_sta(struct ath_softc *sc,
 				    struct ath_beacon_config *conf)
 {
 	struct ath_hw *ah = sc->sc_ah;
 	struct ath_common *common = ath9k_hw_common(ah);
 	struct ath9k_beacon_state bs;
 	int dtimperiod, dtimcount, sleepduration;
 	int cfpperiod, cfpcount;
 	u32 nexttbtt = 0, intval, tsftu;
 	u64 tsf;
 	int num_beacons, offset, dtim_dec_count, cfp_dec_count;

 	/* No need to configure beacon if we are not associated */
 	if (!test_bit(SC_OP_PRIM_STA_VIF, &sc->sc_flags)) {
 		ath_dbg(common, BEACON,
 			"STA is not yet associated..skipping beacon config\n");
 		return;
 	}

 	memset(&bs, 0, sizeof(bs));
 	intval = conf->beacon_interval;

 	/*
 	 * Setup dtim and cfp parameters according to
 	 * last beacon we received (which may be none).
 	 */
 	dtimperiod = conf->dtim_period;
 	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;

 	/*
 	 * Pull nexttbtt forward to reflect the current
 	 * TSF and calculate dtim+cfp state for the result.
 	 */
 	tsf = ath9k_hw_gettsf64(ah);
 	tsftu = TSF_TO_TU(tsf>>32, tsf) + FUDGE;

 	num_beacons = tsftu / intval + 1;
 	offset = tsftu % intval;
 	nexttbtt = tsftu - offset;
 	if (offset)
 		nexttbtt += intval;

 	/* DTIM Beacon every dtimperiod Beacon */
 	dtim_dec_count = num_beacons % dtimperiod;
 	/* CFP every cfpperiod DTIM Beacon */
 	cfp_dec_count = (num_beacons / dtimperiod) % cfpperiod;
 	if (dtim_dec_count)
 		cfp_dec_count++;

 	dtimcount -= dtim_dec_count;
 	if (dtimcount < 0)
 		dtimcount += dtimperiod;

 	cfpcount -= cfp_dec_count;
 	if (cfpcount < 0)
 		cfpcount += cfpperiod;

 	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;

 	ath_dbg(common, BEACON, "tsf: %llu tsftu: %u\n", tsf, tsftu);
 	ath_dbg(common, 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_disable_interrupts(ah);
 	ath9k_hw_set_sta_beacon_timers(ah, &bs);
 	ah->imask |= ATH9K_INT_BMISS;

 	ath9k_hw_set_interrupts(ah);
 	ath9k_hw_enable_interrupts(ah);
 }

 static void ath9k_beacon_config_adhoc(struct ath_softc *sc,
 				      struct ath_beacon_config *conf)
 {
 	struct ath_hw *ah = sc->sc_ah;
 	struct ath_common *common = ath9k_hw_common(ah);
 	u32 intval, nexttbtt;

 	ath9k_reset_beacon_status(sc);

 	intval = TU_TO_USEC(conf->beacon_interval);
 	nexttbtt = intval;

 	if (conf->enable_beacon)
 		ah->imask |= ATH9K_INT_SWBA;
 	else
 		ah->imask &= ~ATH9K_INT_SWBA;

 	ath_dbg(common, BEACON, "IBSS nexttbtt: %u intval: %u conf_intval: %u\n",
 		nexttbtt, intval, conf->beacon_interval);

 	ath9k_beacon_init(sc, nexttbtt, intval);
 }

 bool ath9k_allow_beacon_config(struct ath_softc *sc, struct ieee80211_vif *vif)
 {
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
 	struct ath_vif *avp = (void *)vif->drv_priv;

 	if (sc->sc_ah->opmode == NL80211_IFTYPE_AP) {
 		if ((vif->type != NL80211_IFTYPE_AP) ||
 		    (sc->nbcnvifs > 1)) {
 			ath_dbg(common, CONFIG,
 				"An AP interface is already present !\n");
 			return false;
 		}
 	}

 	if (sc->sc_ah->opmode == NL80211_IFTYPE_STATION) {
 		if ((vif->type == NL80211_IFTYPE_STATION) &&
 		    test_bit(SC_OP_BEACONS, &sc->sc_flags) &&
 		    !avp->primary_sta_vif) {
 			ath_dbg(common, CONFIG,
 				"Beacon already configured for a station interface\n");
 			return false;
 		}
 	}

 	return true;
 }

 static void ath9k_cache_beacon_config(struct ath_softc *sc,
 				      struct ieee80211_bss_conf *bss_conf)
 {
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
 	struct ath_beacon_config *cur_conf = &sc->cur_beacon_conf;

 	ath_dbg(common, BEACON,
 		"Caching beacon data for BSS: %pM\n", bss_conf->bssid);

 	cur_conf->beacon_interval = bss_conf->beacon_int;
 	cur_conf->dtim_period = bss_conf->dtim_period;
 	cur_conf->listen_interval = 1;
 	cur_conf->dtim_count = 1;
 	cur_conf->bmiss_timeout =
 		ATH_DEFAULT_BMISS_LIMIT * cur_conf->beacon_interval;

 	/*
 	 * It looks like mac80211 may end up using beacon interval of zero in
 	 * some cases (at least for mesh point). Avoid getting into an
 	 * infinite loop by using a bit safer value instead. To be safe,
 	 * do sanity check on beacon interval for all operating modes.
 	 */
 	if (cur_conf->beacon_interval == 0)
 		cur_conf->beacon_interval = 100;

 	/*
 	 * We don't parse dtim period from mac80211 during the driver
 	 * initialization as it breaks association with hidden-ssid
 	 * AP and it causes latency in roaming
 	 */
 	if (cur_conf->dtim_period == 0)
 		cur_conf->dtim_period = 1;

 }

 void ath9k_beacon_config(struct ath_softc *sc, struct ieee80211_vif *vif,
 			 u32 changed)
 {
 	struct ieee80211_bss_conf *bss_conf = &vif->bss_conf;
 	struct ath_beacon_config *cur_conf = &sc->cur_beacon_conf;

 	if (sc->sc_ah->opmode == NL80211_IFTYPE_STATION) {
 		ath9k_cache_beacon_config(sc, bss_conf);
 		ath9k_set_beacon(sc);
 		set_bit(SC_OP_BEACONS, &sc->sc_flags);
 	} else {
 		/*
 		 * Take care of multiple interfaces when
 		 * enabling/disabling SWBA.
 		 */
 		if (changed & BSS_CHANGED_BEACON_ENABLED) {
 			if (!bss_conf->enable_beacon &&
 			    (sc->nbcnvifs <= 1)) {
 				cur_conf->enable_beacon = false;
 			} else if (bss_conf->enable_beacon) {
 				cur_conf->enable_beacon = true;
 				ath9k_cache_beacon_config(sc, bss_conf);
 			}
 		}

 		if (cur_conf->beacon_interval) {
 			ath9k_set_beacon(sc);

 			if (cur_conf->enable_beacon)
 				set_bit(SC_OP_BEACONS, &sc->sc_flags);
 			else
 				clear_bit(SC_OP_BEACONS, &sc->sc_flags);
 		}
 	}
 }

 void ath9k_set_beacon(struct ath_softc *sc)
 {
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
 	struct ath_beacon_config *cur_conf = &sc->cur_beacon_conf;

 	switch (sc->sc_ah->opmode) {
 	case NL80211_IFTYPE_AP:
 		ath9k_beacon_config_ap(sc, cur_conf);
 		break;
 	case NL80211_IFTYPE_ADHOC:
 	case NL80211_IFTYPE_MESH_POINT:
 		ath9k_beacon_config_adhoc(sc, cur_conf);
 		break;
 	case NL80211_IFTYPE_STATION:
 		ath9k_beacon_config_sta(sc, cur_conf);
 		break;
 	default:
 		ath_dbg(common, CONFIG, "Unsupported beaconing mode\n");
 		return;
 	}
 }
	/*
	* Copyright (c) 2008-2011 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 <linux/dma-mapping.h>
	#include "ath9k.h"

	#define FUDGE 2

	static void ath9k_reset_beacon_status(struct ath_softc *sc)
	{
	sc->beacon.tx_processed = false;
	sc->beacon.tx_last = false;
	}

	/*
	* 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 void ath9k_beaconq_config(struct ath_softc *sc)
	{
	struct ath_hw *ah = sc->sc_ah;
	struct ath_common *common = ath9k_hw_common(ah);
	struct ath9k_tx_queue_info qi, qi_be;
	struct ath_txq *txq;

	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. */
	txq = sc->tx.txq_map[IEEE80211_AC_BE];
	ath9k_hw_get_txq_props(ah, txq->axq_qnum, &qi_be);
	qi.tqi_aifs = qi_be.tqi_aifs;
	if (ah->slottime == ATH9K_SLOT_TIME_20)
	qi.tqi_cwmin = 2*qi_be.tqi_cwmin;
	else
	qi.tqi_cwmin = 4*qi_be.tqi_cwmin;
	qi.tqi_cwmax = qi_be.tqi_cwmax;
	}

	if (!ath9k_hw_set_txq_props(ah, sc->beacon.beaconq, &qi)) {
	ath_err(common, "Unable to update h/w beacon queue parameters\n");
	} else {
	ath9k_hw_resettxqueue(ah, sc->beacon.beaconq);
	}
	}

	/*
	* Associates the beacon frame buffer with a transmit descriptor. Will set
	* up rate codes, and channel flags. Beacons are always sent out at the
	* lowest rate, and are not retried.
	*/
	static void ath9k_beacon_setup(struct ath_softc sc, struct ieee80211_vif vif,
	struct ath_buf *bf, int rateidx)
	{
	struct sk_buff *skb = bf->bf_mpdu;
	struct ath_hw *ah = sc->sc_ah;
	struct ath_common *common = ath9k_hw_common(ah);
	struct ath_tx_info info;
	struct ieee80211_supported_band *sband;
	u8 chainmask = ah->txchainmask;
	u8 rate = 0;

	sband = &sc->sbands[common->hw->conf.channel->band];
	rate = sband->bitrates[rateidx].hw_value;
	if (vif->bss_conf.use_short_preamble)
	rate \|= sband->bitrates[rateidx].hw_value_short;

	memset(&info, 0, sizeof(info));
	info.pkt_len = skb->len + FCS_LEN;
	info.type = ATH9K_PKT_TYPE_BEACON;
	info.txpower = MAX_RATE_POWER;
	info.keyix = ATH9K_TXKEYIX_INVALID;
	info.keytype = ATH9K_KEY_TYPE_CLEAR;
	info.flags = ATH9K_TXDESC_NOACK \| ATH9K_TXDESC_CLRDMASK;

	info.buf_addr[0] = bf->bf_buf_addr;
	info.buf_len[0] = roundup(skb->len, 4);

	info.is_first = true;
	info.is_last = true;

	info.qcu = sc->beacon.beaconq;

	info.rates[0].Tries = 1;
	info.rates[0].Rate = rate;
	info.rates[0].ChSel = ath_txchainmask_reduction(sc, chainmask, rate);

	ath9k_hw_set_txdesc(ah, bf->bf_desc, &info);
	}

	static void ath9k_tx_cabq(struct ieee80211_hw hw, struct sk_buff skb)
	{
	struct ath_softc *sc = hw->priv;
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_tx_control txctl;

	memset(&txctl, 0, sizeof(struct ath_tx_control));
	txctl.txq = sc->beacon.cabq;

	ath_dbg(common, XMIT, "transmitting CABQ packet, skb: %p\n", skb);

	if (ath_tx_start(hw, skb, &txctl) != 0) {
	ath_dbg(common, XMIT, "CABQ TX failed\n");
	ieee80211_free_txskb(hw, skb);
	}
	}

	static struct ath_buf ath9k_beacon_generate(struct ieee80211_hw hw,
	struct ieee80211_vif *vif)
	{
	struct ath_softc *sc = hw->priv;
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_buf *bf;
	struct ath_vif avp = (void )vif->drv_priv;
	struct sk_buff *skb;
	struct ath_txq *cabq = sc->beacon.cabq;
	struct ieee80211_tx_info *info;
	struct ieee80211_mgmt *mgmt_hdr;
	int cabq_depth;

	if (avp->av_bcbuf == NULL)
	return NULL;

	bf = avp->av_bcbuf;
	skb = bf->bf_mpdu;
	if (skb) {
	dma_unmap_single(sc->dev, bf->bf_buf_addr,
	skb->len, DMA_TO_DEVICE);
	dev_kfree_skb_any(skb);
	bf->bf_buf_addr = 0;
	bf->bf_mpdu = NULL;
	}

	skb = ieee80211_beacon_get(hw, vif);
	if (skb == NULL)
	return NULL;

	bf->bf_mpdu = skb;

	mgmt_hdr = (struct ieee80211_mgmt *)skb->data;
	mgmt_hdr->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 = 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;
	bf->bf_buf_addr = 0;
	ath_err(common, "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) {
	ath_dbg(common, BEACON,
	"Flushing previous cabq traffic\n");
	ath_draintxq(sc, cabq, false);
	}
	}

	ath9k_beacon_setup(sc, vif, bf, info->control.rates[0].idx);

	while (skb) {
	ath9k_tx_cabq(hw, skb);
	skb = ieee80211_get_buffered_bc(hw, vif);
	}

	return bf;
	}

	void ath9k_beacon_assign_slot(struct ath_softc sc, struct ieee80211_vif vif)
	{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_vif avp = (void )vif->drv_priv;
	int slot;

	avp->av_bcbuf = list_first_entry(&sc->beacon.bbuf, struct ath_buf, list);
	list_del(&avp->av_bcbuf->list);

	for (slot = 0; slot < ATH_BCBUF; slot++) {
	if (sc->beacon.bslot[slot] == NULL) {
	avp->av_bslot = slot;
	break;
	}
	}

	sc->beacon.bslot[avp->av_bslot] = vif;
	sc->nbcnvifs++;

	ath_dbg(common, CONFIG, "Added interface at beacon slot: %d\n",
	avp->av_bslot);
	}

	void ath9k_beacon_remove_slot(struct ath_softc sc, struct ieee80211_vif vif)
	{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_vif avp = (void )vif->drv_priv;
	struct ath_buf *bf = avp->av_bcbuf;

	ath_dbg(common, CONFIG, "Removing interface at beacon slot: %d\n",
	avp->av_bslot);

	tasklet_disable(&sc->bcon_tasklet);

	if (bf && bf->bf_mpdu) {
	struct sk_buff *skb = bf->bf_mpdu;
	dma_unmap_single(sc->dev, bf->bf_buf_addr,
	skb->len, DMA_TO_DEVICE);
	dev_kfree_skb_any(skb);
	bf->bf_mpdu = NULL;
	bf->bf_buf_addr = 0;
	}

	avp->av_bcbuf = NULL;
	sc->beacon.bslot[avp->av_bslot] = NULL;
	sc->nbcnvifs--;
	list_add_tail(&bf->list, &sc->beacon.bbuf);

	tasklet_enable(&sc->bcon_tasklet);
	}

	static int ath9k_beacon_choose_slot(struct ath_softc *sc)
	{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_beacon_config *cur_conf = &sc->cur_beacon_conf;
	u16 intval;
	u32 tsftu;
	u64 tsf;
	int slot;

	if (sc->sc_ah->opmode != NL80211_IFTYPE_AP) {
	ath_dbg(common, BEACON, "slot 0, tsf: %llu\n",
	ath9k_hw_gettsf64(sc->sc_ah));
	return 0;
	}

	intval = cur_conf->beacon_interval ? : ATH_DEFAULT_BINTVAL;
	tsf = ath9k_hw_gettsf64(sc->sc_ah);
	tsf += TU_TO_USEC(sc->sc_ah->config.sw_beacon_response_time);
	tsftu = TSF_TO_TU((tsf * ATH_BCBUF) >>32, tsf * ATH_BCBUF);
	slot = (tsftu % (intval * ATH_BCBUF)) / intval;

	ath_dbg(common, BEACON, "slot: %d tsf: %llu tsftu: %u\n",
	slot, tsf, tsftu / ATH_BCBUF);

	return slot;
	}

	void ath9k_set_tsfadjust(struct ath_softc sc, struct ieee80211_vif vif)
	{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_beacon_config *cur_conf = &sc->cur_beacon_conf;
	struct ath_vif avp = (void )vif->drv_priv;
	u64 tsfadjust;

	if (avp->av_bslot == 0)
	return;

	tsfadjust = cur_conf->beacon_interval * avp->av_bslot / ATH_BCBUF;
	avp->tsf_adjust = cpu_to_le64(TU_TO_USEC(tsfadjust));

	ath_dbg(common, CONFIG, "tsfadjust is: %llu for bslot: %d\n",
	(unsigned long long)tsfadjust, avp->av_bslot);
	}

	void ath9k_beacon_tasklet(unsigned long data)
	{
	struct ath_softc sc = (struct ath_softc )data;
	struct ath_hw *ah = sc->sc_ah;
	struct ath_common *common = ath9k_hw_common(ah);
	struct ath_buf *bf = NULL;
	struct ieee80211_vif *vif;
	bool edma = !!(ah->caps.hw_caps & ATH9K_HW_CAP_EDMA);
	int slot;

	if (test_bit(SC_OP_HW_RESET, &sc->sc_flags)) {
	ath_dbg(common, RESET,
	"reset work is pending, skip beaconing now\n");
	return;
	}

	/*
	* 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 (!ath9k_hw_check_alive(ah))
	ieee80211_queue_work(sc->hw, &sc->hw_check_work);

	if (sc->beacon.bmisscnt < BSTUCK_THRESH * sc->nbcnvifs) {
	ath_dbg(common, BSTUCK,
	"missed %u consecutive beacons\n",
	sc->beacon.bmisscnt);
	ath9k_hw_stop_dma_queue(ah, sc->beacon.beaconq);
	if (sc->beacon.bmisscnt > 3)
	ath9k_hw_bstuck_nfcal(ah);
	} else if (sc->beacon.bmisscnt >= BSTUCK_THRESH) {
	ath_dbg(common, BSTUCK, "beacon is officially stuck\n");
	sc->beacon.bmisscnt = 0;
	ath9k_queue_reset(sc, RESET_TYPE_BEACON_STUCK);
	}

	return;
	}

	slot = ath9k_beacon_choose_slot(sc);
	vif = sc->beacon.bslot[slot];

	if (!vif \|\| !vif->bss_conf.enable_beacon)
	return;

	bf = ath9k_beacon_generate(sc->hw, vif);

	if (sc->beacon.bmisscnt != 0) {
	ath_dbg(common, BSTUCK, "resume beacon xmit after %u misses\n",
	sc->beacon.bmisscnt);
	sc->beacon.bmisscnt = 0;
	}

	/*
	* 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;
	sc->beacon.slotupdate = slot;
	} else if (sc->beacon.updateslot == COMMIT &&
	sc->beacon.slotupdate == slot) {
	ah->slottime = sc->beacon.slottime;
	ath9k_hw_init_global_settings(ah);
	sc->beacon.updateslot = OK;
	}

	if (bf) {
	ath9k_reset_beacon_status(sc);

	ath_dbg(common, BEACON,
	"Transmitting beacon for slot: %d\n", slot);

	/* NB: cabq traffic should already be queued and primed */
	ath9k_hw_puttxbuf(ah, sc->beacon.beaconq, bf->bf_daddr);

	if (!edma)
	ath9k_hw_txstart(ah, sc->beacon.beaconq);
	}
	}

	static void ath9k_beacon_init(struct ath_softc *sc, u32 nexttbtt, u32 intval)
	{
	struct ath_hw *ah = sc->sc_ah;

	ath9k_hw_disable_interrupts(ah);
	ath9k_hw_reset_tsf(ah);
	ath9k_beaconq_config(sc);
	ath9k_hw_beaconinit(ah, nexttbtt, intval);
	sc->beacon.bmisscnt = 0;
	ath9k_hw_set_interrupts(ah);
	ath9k_hw_enable_interrupts(ah);
	}

	/*
	* 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 ath9k_beacon_config_ap(struct ath_softc *sc,
	struct ath_beacon_config *conf)
	{
	struct ath_hw *ah = sc->sc_ah;
	struct ath_common *common = ath9k_hw_common(ah);
	u32 nexttbtt, intval;

	/* NB: the beacon interval is kept internally in TU's */
	intval = TU_TO_USEC(conf->beacon_interval);
	intval /= ATH_BCBUF;
	nexttbtt = intval;

	if (conf->enable_beacon)
	ah->imask \|= ATH9K_INT_SWBA;
	else
	ah->imask &= ~ATH9K_INT_SWBA;

	ath_dbg(common, BEACON, "AP nexttbtt: %u intval: %u conf_intval: %u\n",
	nexttbtt, intval, conf->beacon_interval);

	ath9k_beacon_init(sc, nexttbtt, intval);
	}

	/*
	* 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 ath9k_beacon_config_sta(struct ath_softc *sc,
	struct ath_beacon_config *conf)
	{
	struct ath_hw *ah = sc->sc_ah;
	struct ath_common *common = ath9k_hw_common(ah);
	struct ath9k_beacon_state bs;
	int dtimperiod, dtimcount, sleepduration;
	int cfpperiod, cfpcount;
	u32 nexttbtt = 0, intval, tsftu;
	u64 tsf;
	int num_beacons, offset, dtim_dec_count, cfp_dec_count;

	/* No need to configure beacon if we are not associated */
	if (!test_bit(SC_OP_PRIM_STA_VIF, &sc->sc_flags)) {
	ath_dbg(common, BEACON,
	"STA is not yet associated..skipping beacon config\n");
	return;
	}

	memset(&bs, 0, sizeof(bs));
	intval = conf->beacon_interval;

	/*
	* Setup dtim and cfp parameters according to
	* last beacon we received (which may be none).
	*/
	dtimperiod = conf->dtim_period;
	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;

	/*
	* Pull nexttbtt forward to reflect the current
	* TSF and calculate dtim+cfp state for the result.
	*/
	tsf = ath9k_hw_gettsf64(ah);
	tsftu = TSF_TO_TU(tsf>>32, tsf) + FUDGE;

	num_beacons = tsftu / intval + 1;
	offset = tsftu % intval;
	nexttbtt = tsftu - offset;
	if (offset)
	nexttbtt += intval;

	/* DTIM Beacon every dtimperiod Beacon */
	dtim_dec_count = num_beacons % dtimperiod;
	/* CFP every cfpperiod DTIM Beacon */
	cfp_dec_count = (num_beacons / dtimperiod) % cfpperiod;
	if (dtim_dec_count)
	cfp_dec_count++;

	dtimcount -= dtim_dec_count;
	if (dtimcount < 0)
	dtimcount += dtimperiod;

	cfpcount -= cfp_dec_count;
	if (cfpcount < 0)
	cfpcount += cfpperiod;

	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;

	ath_dbg(common, BEACON, "tsf: %llu tsftu: %u\n", tsf, tsftu);
	ath_dbg(common, 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_disable_interrupts(ah);
	ath9k_hw_set_sta_beacon_timers(ah, &bs);
	ah->imask \|= ATH9K_INT_BMISS;

	ath9k_hw_set_interrupts(ah);
	ath9k_hw_enable_interrupts(ah);
	}

	static void ath9k_beacon_config_adhoc(struct ath_softc *sc,
	struct ath_beacon_config *conf)
	{
	struct ath_hw *ah = sc->sc_ah;
	struct ath_common *common = ath9k_hw_common(ah);
	u32 intval, nexttbtt;

	ath9k_reset_beacon_status(sc);

	intval = TU_TO_USEC(conf->beacon_interval);
	nexttbtt = intval;

	if (conf->enable_beacon)
	ah->imask \|= ATH9K_INT_SWBA;
	else
	ah->imask &= ~ATH9K_INT_SWBA;

	ath_dbg(common, BEACON, "IBSS nexttbtt: %u intval: %u conf_intval: %u\n",
	nexttbtt, intval, conf->beacon_interval);

	ath9k_beacon_init(sc, nexttbtt, intval);
	}

	bool ath9k_allow_beacon_config(struct ath_softc sc, struct ieee80211_vif vif)
	{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_vif avp = (void )vif->drv_priv;

	if (sc->sc_ah->opmode == NL80211_IFTYPE_AP) {
	if ((vif->type != NL80211_IFTYPE_AP) \|\|
	(sc->nbcnvifs > 1)) {
	ath_dbg(common, CONFIG,
	"An AP interface is already present !\n");
	return false;
	}
	}

	if (sc->sc_ah->opmode == NL80211_IFTYPE_STATION) {
	if ((vif->type == NL80211_IFTYPE_STATION) &&
	test_bit(SC_OP_BEACONS, &sc->sc_flags) &&
	!avp->primary_sta_vif) {
	ath_dbg(common, CONFIG,
	"Beacon already configured for a station interface\n");
	return false;
	}
	}

	return true;
	}

	static void ath9k_cache_beacon_config(struct ath_softc *sc,
	struct ieee80211_bss_conf *bss_conf)
	{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_beacon_config *cur_conf = &sc->cur_beacon_conf;

	ath_dbg(common, BEACON,
	"Caching beacon data for BSS: %pM\n", bss_conf->bssid);

	cur_conf->beacon_interval = bss_conf->beacon_int;
	cur_conf->dtim_period = bss_conf->dtim_period;
	cur_conf->listen_interval = 1;
	cur_conf->dtim_count = 1;
	cur_conf->bmiss_timeout =
	ATH_DEFAULT_BMISS_LIMIT * cur_conf->beacon_interval;

	/*
	* It looks like mac80211 may end up using beacon interval of zero in
	* some cases (at least for mesh point). Avoid getting into an
	* infinite loop by using a bit safer value instead. To be safe,
	* do sanity check on beacon interval for all operating modes.
	*/
	if (cur_conf->beacon_interval == 0)
	cur_conf->beacon_interval = 100;

	/*
	* We don't parse dtim period from mac80211 during the driver
	* initialization as it breaks association with hidden-ssid
	* AP and it causes latency in roaming
	*/
	if (cur_conf->dtim_period == 0)
	cur_conf->dtim_period = 1;

	}

	void ath9k_beacon_config(struct ath_softc sc, struct ieee80211_vif vif,
	u32 changed)
	{
	struct ieee80211_bss_conf *bss_conf = &vif->bss_conf;
	struct ath_beacon_config *cur_conf = &sc->cur_beacon_conf;

	if (sc->sc_ah->opmode == NL80211_IFTYPE_STATION) {
	ath9k_cache_beacon_config(sc, bss_conf);
	ath9k_set_beacon(sc);
	set_bit(SC_OP_BEACONS, &sc->sc_flags);
	} else {
	/*
	* Take care of multiple interfaces when
	* enabling/disabling SWBA.
	*/
	if (changed & BSS_CHANGED_BEACON_ENABLED) {
	if (!bss_conf->enable_beacon &&
	(sc->nbcnvifs <= 1)) {
	cur_conf->enable_beacon = false;
	} else if (bss_conf->enable_beacon) {
	cur_conf->enable_beacon = true;
	ath9k_cache_beacon_config(sc, bss_conf);
	}
	}

	if (cur_conf->beacon_interval) {
	ath9k_set_beacon(sc);

	if (cur_conf->enable_beacon)
	set_bit(SC_OP_BEACONS, &sc->sc_flags);
	else
	clear_bit(SC_OP_BEACONS, &sc->sc_flags);
	}
	}
	}

	void ath9k_set_beacon(struct ath_softc *sc)
	{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_beacon_config *cur_conf = &sc->cur_beacon_conf;

	switch (sc->sc_ah->opmode) {
	case NL80211_IFTYPE_AP:
	ath9k_beacon_config_ap(sc, cur_conf);
	break;
	case NL80211_IFTYPE_ADHOC:
	case NL80211_IFTYPE_MESH_POINT:
	ath9k_beacon_config_adhoc(sc, cur_conf);
	break;
	case NL80211_IFTYPE_STATION:
	ath9k_beacon_config_sta(sc, cur_conf);
	break;
	default:
	ath_dbg(common, CONFIG, "Unsupported beaconing mode\n");
	return;
	}
	}