ath9k: Add new Atheros IEEE 802.11n driver

This adds the new mac80211 11n ath9k Atheros driver. Only STA support
is currently enabled and tested.

Signed-off-by: Senthil Balasubramanian <senthilkumar@atheros.com>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Jack Howarth <howarth@bromo.msbb.uc.edu>
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: Sujith Manoharan <Sujith.Manoharan@atheros.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 977 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath9k/beacon.c b/drivers/net/wireless/ath9k/beacon.c
new file mode 100644
index 0000000..00993f8
--- /dev/null
+++ b/drivers/net/wireless/ath9k/beacon.c
@@ -0,0 +1,977 @@
+/*
+ * Copyright (c) 2008 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.
+ */
+
+ /* Implementation of beacon processing. */
+
+#include <asm/unaligned.h>
+#include "core.h"
+
+/*
+ *  Configure parameters for the beacon queue
+ *
+ *  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_hal *ah = sc->sc_ah;
+	struct ath9k_txq_info qi;
+
+	ath9k_hw_gettxqueueprops(ah, sc->sc_bhalq, &qi);
+	if (sc->sc_opmode == ATH9K_M_HOSTAP) {
+		/* 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->sc_beacon_qi.tqi_aifs;
+		qi.tqi_cwmin = 2*sc->sc_beacon_qi.tqi_cwmin;
+		qi.tqi_cwmax = sc->sc_beacon_qi.tqi_cwmax;
+	}
+
+	if (!ath9k_hw_settxqueueprops(ah, sc->sc_bhalq, &qi)) {
+		DPRINTF(sc, ATH_DBG_FATAL,
+			"%s: unable to update h/w beacon queue parameters\n",
+			__func__);
+		return 0;
+	} else {
+		ath9k_hw_resettxqueue(ah, sc->sc_bhalq); /* push to h/w */
+		return 1;
+	}
+}
+
+/*
+ *  Setup the beacon frame for transmit.
+ *
+ *  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_vap *avp, struct ath_buf *bf)
+{
+	struct sk_buff *skb = (struct sk_buff *)bf->bf_mpdu;
+	struct ath_hal *ah = sc->sc_ah;
+	struct ath_desc *ds;
+	int flags, antenna;
+	const struct ath9k_rate_table *rt;
+	u8 rix, rate;
+	int ctsrate = 0;
+	int ctsduration = 0;
+	struct ath9k_11n_rate_series  series[4];
+
+	DPRINTF(sc, ATH_DBG_BEACON, "%s: m %p len %u\n",
+		__func__, skb, skb->len);
+
+	/* setup descriptors */
+	ds = bf->bf_desc;
+
+	flags = ATH9K_TXDESC_NOACK;
+
+	if (sc->sc_opmode == ATH9K_M_IBSS && ah->ah_caps.halVEOLSupport) {
+		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's
+		 * XXX assumes two antenna
+		 */
+		antenna = ((sc->ast_be_xmit / sc->sc_nbcnvaps) & 1 ? 2 : 1);
+	}
+
+	ds->ds_data = bf->bf_buf_addr;
+
+	/*
+	 * Calculate rate code.
+	 * XXX everything at min xmit rate
+	 */
+	rix = sc->sc_minrateix;
+	rt = sc->sc_currates;
+	rate = rt->info[rix].rateCode;
+	if (sc->sc_flags & ATH_PREAMBLE_SHORT)
+		rate |= rt->info[rix].shortPreamble;
+
+	ath9k_hw_set11n_txdesc(ah, ds
+			      , skb->len + FCS_LEN /* frame length */
+			      , ATH9K_PKT_TYPE_BEACON /* Atheros packet type */
+			      , avp->av_btxctl.txpower /* txpower XXX */
+			      , ATH9K_TXKEYIX_INVALID /* no encryption */
+			      , ATH9K_KEY_TYPE_CLEAR /* no encryption */
+			      , flags /* no ack, veol for beacons */
+		);
+
+	/* NB: beacon's BufLen must be a multiple of 4 bytes */
+	ath9k_hw_filltxdesc(ah, ds
+			   , roundup(skb->len, 4) /* buffer length */
+			   , true /* first segment */
+			   , true /* last segment */
+			   , ds /* first descriptor */
+		);
+
+	memzero(series, sizeof(struct ath9k_11n_rate_series) * 4);
+	series[0].Tries = 1;
+	series[0].Rate = rate;
+	series[0].ChSel = sc->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);
+}
+
+/* Move everything from the vap's mcast queue to the hardware cab queue.
+ * Caller must hold mcasq lock and cabq lock
+ * XXX MORE_DATA bit?
+ */
+static void empty_mcastq_into_cabq(struct ath_hal *ah,
+	struct ath_txq *mcastq, struct ath_txq *cabq)
+{
+	struct ath_buf *bfmcast;
+
+	BUG_ON(list_empty(&mcastq->axq_q));
+
+	bfmcast = list_first_entry(&mcastq->axq_q, struct ath_buf, list);
+
+	/* link the descriptors */
+	if (!cabq->axq_link)
+		ath9k_hw_puttxbuf(ah, cabq->axq_qnum, bfmcast->bf_daddr);
+	else
+		*cabq->axq_link = bfmcast->bf_daddr;
+
+	/* append the private vap mcast list to  the cabq */
+
+	cabq->axq_depth	+= mcastq->axq_depth;
+	cabq->axq_totalqueued += mcastq->axq_totalqueued;
+	cabq->axq_linkbuf = mcastq->axq_linkbuf;
+	cabq->axq_link = mcastq->axq_link;
+	list_splice_tail_init(&mcastq->axq_q, &cabq->axq_q);
+	mcastq->axq_depth = 0;
+	mcastq->axq_totalqueued = 0;
+	mcastq->axq_linkbuf = NULL;
+	mcastq->axq_link = NULL;
+}
+
+/* This is only run at DTIM. We move everything from the vap's mcast queue
+ * to the hardware cab queue. Caller must hold the mcastq lock. */
+static void trigger_mcastq(struct ath_hal *ah,
+	struct ath_txq *mcastq, struct ath_txq *cabq)
+{
+	spin_lock_bh(&cabq->axq_lock);
+
+	if (!list_empty(&mcastq->axq_q))
+		empty_mcastq_into_cabq(ah, mcastq, cabq);
+
+	/* cabq is gated by beacon so it is safe to start here */
+	if (!list_empty(&cabq->axq_q))
+		ath9k_hw_txstart(ah, cabq->axq_qnum);
+
+	spin_unlock_bh(&cabq->axq_lock);
+}
+
+/*
+ *  Generate beacon frame and queue cab data for a vap.
+ *
+ *  Updates the contents of the beacon frame.  It is assumed that the buffer for
+ *  the beacon frame has been allocated in the ATH object, and simply needs to
+ *  be filled for this cycle.  Also, any CAB (crap after beacon?) traffic will
+ *  be added to the beacon frame at this point.
+*/
+static struct ath_buf *ath_beacon_generate(struct ath_softc *sc, int if_id)
+{
+	struct ath_hal *ah = sc->sc_ah;
+	struct ath_buf *bf;
+	struct ath_vap *avp;
+	struct sk_buff *skb;
+	int cabq_depth;
+	int mcastq_depth;
+	int is_beacon_dtim = 0;
+	unsigned int curlen;
+	struct ath_txq *cabq;
+	struct ath_txq *mcastq;
+	avp = sc->sc_vaps[if_id];
+
+	mcastq = &avp->av_mcastq;
+	cabq = sc->sc_cabq;
+
+	ASSERT(avp);
+
+	if (avp->av_bcbuf == NULL) {
+		DPRINTF(sc, ATH_DBG_BEACON, "%s: avp=%p av_bcbuf=%p\n",
+			__func__, avp, avp->av_bcbuf);
+		return NULL;
+	}
+	bf = avp->av_bcbuf;
+	skb = (struct sk_buff *) bf->bf_mpdu;
+
+	/*
+	 * Update dynamic beacon contents.  If this returns
+	 * non-zero then we need to remap the memory because
+	 * the beacon frame changed size (probably because
+	 * of the TIM bitmap).
+	 */
+	curlen = skb->len;
+
+	/* XXX: spin_lock_bh should not be used here, but sparse bitches
+	 * otherwise. We should fix sparse :) */
+	spin_lock_bh(&mcastq->axq_lock);
+	mcastq_depth = avp->av_mcastq.axq_depth;
+
+	if (ath_update_beacon(sc, if_id, &avp->av_boff, skb, mcastq_depth) ==
+	    1) {
+		ath_skb_unmap_single(sc, skb, PCI_DMA_TODEVICE,
+				     get_dma_mem_context(bf, bf_dmacontext));
+		bf->bf_buf_addr = ath_skb_map_single(sc, skb, PCI_DMA_TODEVICE,
+			get_dma_mem_context(bf, bf_dmacontext));
+	} else {
+		pci_dma_sync_single_for_cpu(sc->pdev,
+					    bf->bf_buf_addr,
+					    skb_tailroom(skb),
+					    PCI_DMA_TODEVICE);
+	}
+
+	/*
+	 * if the CABQ traffic from previous DTIM is pending and the current
+	 *  beacon is also a DTIM.
+	 *  1) if there is only one vap let the cab traffic continue.
+	 *  2) if there are more than one vap and we are using staggered
+	 *     beacons, then drain the cabq by dropping all the frames in
+	 *     the cabq so that the current vaps cab traffic can be scheduled.
+	 */
+	spin_lock_bh(&cabq->axq_lock);
+	cabq_depth = cabq->axq_depth;
+	spin_unlock_bh(&cabq->axq_lock);
+
+	is_beacon_dtim = avp->av_boff.bo_tim[4] & 1;
+
+	if (mcastq_depth && is_beacon_dtim && cabq_depth) {
+		/*
+		 * Unlock the cabq lock as ath_tx_draintxq acquires
+		 * the lock again which is a common function and that
+		 * acquires txq lock inside.
+		 */
+		if (sc->sc_nvaps > 1) {
+			ath_tx_draintxq(sc, cabq, false);
+			DPRINTF(sc, ATH_DBG_BEACON,
+				"%s: flush previous cabq traffic\n", __func__);
+		}
+	}
+
+	/* Construct tx descriptor. */
+	ath_beacon_setup(sc, avp, bf);
+
+	/*
+	 * Enable the CAB queue before the beacon queue to
+	 * insure cab frames are triggered by this beacon.
+	 */
+	if (is_beacon_dtim)
+		trigger_mcastq(ah, mcastq, cabq);
+
+	spin_unlock_bh(&mcastq->axq_lock);
+	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, int if_id)
+{
+	struct ath_hal *ah = sc->sc_ah;
+	struct ath_buf *bf;
+	struct ath_vap *avp;
+	struct sk_buff *skb;
+
+	avp = sc->sc_vaps[if_id];
+	ASSERT(avp);
+
+	if (avp->av_bcbuf == NULL) {
+		DPRINTF(sc, ATH_DBG_BEACON, "%s: avp=%p av_bcbuf=%p\n",
+			__func__, avp, avp != NULL ? avp->av_bcbuf : NULL);
+		return;
+	}
+	bf = avp->av_bcbuf;
+	skb = (struct sk_buff *) bf->bf_mpdu;
+
+	/* Construct tx descriptor. */
+	ath_beacon_setup(sc, avp, bf);
+
+	/* NB: caller is known to have already stopped tx dma */
+	ath9k_hw_puttxbuf(ah, sc->sc_bhalq, bf->bf_daddr);
+	ath9k_hw_txstart(ah, sc->sc_bhalq);
+	DPRINTF(sc, ATH_DBG_BEACON, "%s: TXDP%u = %llx (%p)\n", __func__,
+		sc->sc_bhalq, ito64(bf->bf_daddr), bf->bf_desc);
+}
+
+/*
+ *  Setup a h/w transmit queue for beacons.
+ *
+ *  This function allocates an information structure (struct ath9k_txq_info)
+ *  on the stack, sets some specific parameters (zero out channel width
+ *  min/max, and enable aifs). The info structure does not need to be
+ *  persistant.
+*/
+
+int ath_beaconq_setup(struct ath_hal *ah)
+{
+	struct ath9k_txq_info qi;
+
+	memzero(&qi, 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);
+}
+
+
+/*
+ *  Allocate and setup an initial beacon frame.
+ *
+ *  Allocate a beacon state variable for a specific VAP instance created on
+ *  the ATH interface.  This routine also calculates the beacon "slot" for
+ *  staggared beacons in the mBSSID case.
+*/
+
+int ath_beacon_alloc(struct ath_softc *sc, int if_id)
+{
+	struct ath_vap *avp;
+	struct ieee80211_hdr *wh;
+	struct ath_buf *bf;
+	struct sk_buff *skb;
+
+	avp = sc->sc_vaps[if_id];
+	ASSERT(avp);
+
+	/* 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->sc_bbuf,
+				struct ath_buf, list);
+		list_del(&avp->av_bcbuf->list);
+
+		if (sc->sc_opmode == ATH9K_M_HOSTAP ||
+			!sc->sc_ah->ah_caps.halVEOLSupport) {
+			int slot;
+			/*
+			 * Assign the vap 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->sc_bslot[slot] == ATH_IF_ID_ANY) {
+					/*
+					 * XXX hack, space out slots to better
+					 * deal with misses
+					 */
+					if (slot+1 < ATH_BCBUF &&
+					    sc->sc_bslot[slot+1] ==
+						ATH_IF_ID_ANY) {
+						avp->av_bslot = slot+1;
+						break;
+					}
+					avp->av_bslot = slot;
+					/* NB: keep looking for a double slot */
+				}
+			BUG_ON(sc->sc_bslot[avp->av_bslot] != ATH_IF_ID_ANY);
+			sc->sc_bslot[avp->av_bslot] = if_id;
+			sc->sc_nbcnvaps++;
+		}
+	}
+
+	/* release the previous beacon frame , if it already exists. */
+	bf = avp->av_bcbuf;
+	if (bf->bf_mpdu != NULL) {
+		skb = (struct sk_buff *)bf->bf_mpdu;
+		ath_skb_unmap_single(sc, skb, PCI_DMA_TODEVICE,
+				     get_dma_mem_context(bf, bf_dmacontext));
+		dev_kfree_skb_any(skb);
+		bf->bf_mpdu = NULL;
+	}
+
+	/*
+	 * NB: the beacon data buffer must be 32-bit aligned;
+	 * we assume the wbuf routines will return us something
+	 * with this alignment (perhaps should assert).
+	 * FIXME: Fill avp->av_boff.bo_tim,avp->av_btxctl.txpower and
+	 * avp->av_btxctl.shortPreamble
+	 */
+	skb = ieee80211_beacon_get(sc->hw, avp->av_if_data);
+	if (skb == NULL) {
+		DPRINTF(sc, ATH_DBG_BEACON, "%s: cannot get skb\n",
+			__func__);
+		return -ENOMEM;
+	}
+
+	/*
+	 * Calculate a TSF adjustment factor required for
+	 * staggered beacons.  Note that we assume the format
+	 * of the beacon frame leaves the tstamp field immediately
+	 * following the header.
+	 */
+	if (avp->av_bslot > 0) {
+		u64 tsfadjust;
+		__le64 val;
+		int intval;
+
+		/* FIXME: Use default value for now: Sujith */
+
+		intval = ATH_DEFAULT_BINTVAL;
+
+		/*
+		 * The beacon interval is in TU's; the TSF in usecs.
+		 * We figure out how many TU's to add to align the
+		 * timestamp then convert to TSF units and handle
+		 * byte swapping before writing it in the frame.
+		 * The hardware will then add this each time a beacon
+		 * frame is sent.  Note that we align vap's 1..N
+		 * and leave vap 0 untouched.  This means vap 0
+		 * has a timestamp in one beacon interval while the
+		 * others get a timestamp aligned to the next interval.
+		 */
+		tsfadjust = (intval * (ATH_BCBUF - avp->av_bslot)) / ATH_BCBUF;
+		val = cpu_to_le64(tsfadjust << 10);     /* TU->TSF */
+
+		DPRINTF(sc, ATH_DBG_BEACON,
+			"%s: %s beacons, bslot %d intval %u tsfadjust %llu\n",
+			__func__, "stagger",
+			avp->av_bslot, intval, (unsigned long long)tsfadjust);
+
+		wh = (struct ieee80211_hdr *)skb->data;
+		memcpy(&wh[1], &val, sizeof(val));
+	}
+
+	bf->bf_buf_addr = ath_skb_map_single(sc, skb, PCI_DMA_TODEVICE,
+		get_dma_mem_context(bf, bf_dmacontext));
+	bf->bf_mpdu = skb;
+
+	return 0;
+}
+
+/*
+ *  Reclaim beacon resources and return buffer to the pool.
+ *
+ *  Checks the VAP to put the beacon frame buffer back to the ATH object
+ *  queue, and de-allocates any wbuf frames that were sent as CAB traffic.
+*/
+
+void ath_beacon_return(struct ath_softc *sc, struct ath_vap *avp)
+{
+	if (avp->av_bcbuf != NULL) {
+		struct ath_buf *bf;
+
+		if (avp->av_bslot != -1) {
+			sc->sc_bslot[avp->av_bslot] = ATH_IF_ID_ANY;
+			sc->sc_nbcnvaps--;
+		}
+
+		bf = avp->av_bcbuf;
+		if (bf->bf_mpdu != NULL) {
+			struct sk_buff *skb = (struct sk_buff *)bf->bf_mpdu;
+			ath_skb_unmap_single(sc, skb, PCI_DMA_TODEVICE,
+				get_dma_mem_context(bf, bf_dmacontext));
+			dev_kfree_skb_any(skb);
+			bf->bf_mpdu = NULL;
+		}
+		list_add_tail(&bf->list, &sc->sc_bbuf);
+
+		avp->av_bcbuf = NULL;
+	}
+}
+
+/*
+ *  Reclaim beacon resources and return buffer to the pool.
+ *
+ *  This function will free any wbuf frames that are still attached to the
+ *  beacon buffers in the ATH object.  Note that this does not de-allocate
+ *  any wbuf objects that are in the transmit queue and have not yet returned
+ *  to the ATH object.
+*/
+
+void ath_beacon_free(struct ath_softc *sc)
+{
+	struct ath_buf *bf;
+
+	list_for_each_entry(bf, &sc->sc_bbuf, list) {
+		if (bf->bf_mpdu != NULL) {
+			struct sk_buff *skb = (struct sk_buff *) bf->bf_mpdu;
+			ath_skb_unmap_single(sc, skb, PCI_DMA_TODEVICE,
+				get_dma_mem_context(bf, bf_dmacontext));
+			dev_kfree_skb_any(skb);
+			bf->bf_mpdu = NULL;
+		}
+	}
+}
+
+/*
+ * Tasklet for Sending Beacons
+ *
+ * Transmit one or more beacon frames at SWBA.  Dynamic updates to the frame
+ * contents are done as needed and the slot time is also adjusted based on
+ * current state.
+ *
+ * This tasklet is not scheduled, it's called in ISR context.
+*/
+
+void ath9k_beacon_tasklet(unsigned long data)
+{
+#define TSF_TO_TU(_h,_l)					\
+	((((u32)(_h)) << 22) | (((u32)(_l)) >> 10))
+
+	struct ath_softc *sc = (struct ath_softc *)data;
+	struct ath_hal *ah = sc->sc_ah;
+	struct ath_buf *bf = NULL;
+	int slot, if_id;
+	u32 bfaddr;
+	u32 rx_clear = 0, rx_frame = 0, tx_frame = 0;
+	u32 show_cycles = 0;
+	u32 bc = 0; /* beacon count */
+	u64 tsf;
+	u32 tsftu;
+	u16 intval;
+
+	if (sc->sc_noreset) {
+		show_cycles = ath9k_hw_GetMibCycleCountsPct(ah,
+							    &rx_clear,
+							    &rx_frame,
+							    &tx_frame);
+	}
+
+	/*
+	 * 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->sc_bhalq) != 0) {
+		sc->sc_bmisscount++;
+		/* XXX: doth needs the chanchange IE countdown decremented.
+		 *      We should consider adding a mac80211 call to indicate
+		 *      a beacon miss so appropriate action could be taken
+		 *      (in that layer).
+		 */
+		if (sc->sc_bmisscount < BSTUCK_THRESH) {
+			if (sc->sc_noreset) {
+				DPRINTF(sc, ATH_DBG_BEACON,
+					"%s: missed %u consecutive beacons\n",
+					__func__, sc->sc_bmisscount);
+				if (show_cycles) {
+					/*
+					 * Display cycle counter stats
+					 * from HW to aide in debug of
+					 * stickiness.
+					 */
+					DPRINTF(sc,
+						ATH_DBG_BEACON,
+						"%s: busy times: rx_clear=%d, "
+						"rx_frame=%d, tx_frame=%d\n",
+						__func__, rx_clear, rx_frame,
+						tx_frame);
+				} else {
+					DPRINTF(sc,
+						ATH_DBG_BEACON,
+						"%s: unable to obtain "
+						"busy times\n", __func__);
+				}
+			} else {
+				DPRINTF(sc, ATH_DBG_BEACON,
+					"%s: missed %u consecutive beacons\n",
+					__func__, sc->sc_bmisscount);
+			}
+		} else if (sc->sc_bmisscount >= BSTUCK_THRESH) {
+			if (sc->sc_noreset) {
+				if (sc->sc_bmisscount == BSTUCK_THRESH) {
+					DPRINTF(sc,
+						ATH_DBG_BEACON,
+						"%s: beacon is officially "
+						"stuck\n", __func__);
+					ath9k_hw_dmaRegDump(ah);
+				}
+			} else {
+				DPRINTF(sc, ATH_DBG_BEACON,
+					"%s: beacon is officially stuck\n",
+					__func__);
+				ath_bstuck_process(sc);
+			}
+		}
+
+		return;
+	}
+	if (sc->sc_bmisscount != 0) {
+		if (sc->sc_noreset) {
+			DPRINTF(sc,
+				ATH_DBG_BEACON,
+				"%s: resume beacon xmit after %u misses\n",
+				__func__, sc->sc_bmisscount);
+		} else {
+			DPRINTF(sc, ATH_DBG_BEACON,
+				"%s: resume beacon xmit after %u misses\n",
+				__func__, sc->sc_bmisscount);
+		}
+		sc->sc_bmisscount = 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.
+	 */
+
+	/* FIXME: Use default value for now - Sujith */
+	intval = ATH_DEFAULT_BINTVAL;
+
+	tsf = ath9k_hw_gettsf64(ah);
+	tsftu = TSF_TO_TU(tsf>>32, tsf);
+	slot = ((tsftu % intval) * ATH_BCBUF) / intval;
+	if_id = sc->sc_bslot[(slot + 1) % ATH_BCBUF];
+	DPRINTF(sc, ATH_DBG_BEACON,
+			"%s: slot %d [tsf %llu tsftu %u intval %u] if_id %d\n",
+			__func__, slot, (unsigned long long) tsf, tsftu,
+			intval, if_id);
+	bfaddr = 0;
+	if (if_id != ATH_IF_ID_ANY) {
+		bf = ath_beacon_generate(sc, if_id);
+		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.
+	 */
+	/* XXX locking */
+	if (sc->sc_updateslot == UPDATE) {
+		sc->sc_updateslot = COMMIT; /* commit next beacon */
+		sc->sc_slotupdate = slot;
+	} else if (sc->sc_updateslot == COMMIT && sc->sc_slotupdate == slot)
+		ath_setslottime(sc);        /* commit change to hardware */
+
+	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->sc_bhalq)) {
+			DPRINTF(sc, ATH_DBG_FATAL,
+				"%s: beacon queue %u did not stop?\n",
+				__func__, sc->sc_bhalq);
+			/* NB: the HAL still stops DMA, so proceed */
+		}
+
+		/* NB: cabq traffic should already be queued and primed */
+		ath9k_hw_puttxbuf(ah, sc->sc_bhalq, bfaddr);
+		ath9k_hw_txstart(ah, sc->sc_bhalq);
+
+		sc->ast_be_xmit += bc;     /* XXX per-vap? */
+	}
+#undef TSF_TO_TU
+}
+
+/*
+ *  Tasklet for Beacon Stuck processing
+ *
+ *  Processing for Beacon Stuck.
+ *  Basically calls the ath_internal_reset function to reset the chip.
+*/
+
+void ath_bstuck_process(struct ath_softc *sc)
+{
+	DPRINTF(sc, ATH_DBG_BEACON,
+		"%s: stuck beacon; resetting (bmiss count %u)\n",
+		__func__, sc->sc_bmisscount);
+	ath_internal_reset(sc);
+}
+
+/*
+ * Configure the beacon and sleep timers.
+ *
+ * When operating as an AP this resets the TSF and sets
+ * up the hardware to notify us when we need to issue beacons.
+ *
+ * When operating in station mode 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.
+ */
+
+void ath_beacon_config(struct ath_softc *sc, int if_id)
+{
+#define TSF_TO_TU(_h,_l)					\
+	((((u32)(_h)) << 22) | (((u32)(_l)) >> 10))
+	struct ath_hal *ah = sc->sc_ah;
+	u32 nexttbtt, intval;
+	struct ath_beacon_config conf;
+	enum ath9k_opmode av_opmode;
+
+	if (if_id != ATH_IF_ID_ANY)
+		av_opmode = sc->sc_vaps[if_id]->av_opmode;
+	else
+		av_opmode = sc->sc_opmode;
+
+	memzero(&conf, sizeof(struct ath_beacon_config));
+
+	/* FIXME: Use default values for now - Sujith */
+	/* Query beacon configuration first */
+	/*
+	 * Protocol stack doesn't support dynamic beacon configuration,
+	 * use default configurations.
+	 */
+	conf.beacon_interval = 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;
+
+	/* extract tstamp from last beacon and convert to TU */
+	nexttbtt = TSF_TO_TU(get_unaligned_le32(conf.u.last_tstamp + 4),
+			     get_unaligned_le32(conf.u.last_tstamp));
+	/* XXX conditionalize multi-bss support? */
+	if (sc->sc_opmode == ATH9K_M_HOSTAP) {
+		/*
+		 * 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.
+		 */
+		/* NB: the beacon interval is kept internally in TU's */
+		intval = conf.beacon_interval & ATH9K_BEACON_PERIOD;
+		intval /= ATH_BCBUF;    /* for staggered beacons */
+	} else {
+		intval = conf.beacon_interval & ATH9K_BEACON_PERIOD;
+	}
+
+	if (nexttbtt == 0)      /* e.g. for ap mode */
+		nexttbtt = intval;
+	else if (intval)        /* NB: can be 0 for monitor mode */
+		nexttbtt = roundup(nexttbtt, intval);
+	DPRINTF(sc, ATH_DBG_BEACON, "%s: nexttbtt %u intval %u (%u)\n",
+		__func__, nexttbtt, intval, conf.beacon_interval);
+	/* Check for ATH9K_M_HOSTAP and sc_nostabeacons for WDS client */
+	if (sc->sc_opmode == ATH9K_M_STA) {
+		struct ath9k_beacon_state bs;
+		u64 tsf;
+		u32 tsftu;
+		int dtimperiod, dtimcount, sleepduration;
+		int cfpperiod, cfpcount;
+
+		/*
+		 * 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;      /* XXX? */
+		cfpperiod = 1;          /* NB: no PCF support yet */
+		cfpcount = 0;
+
+		sleepduration = conf.listen_interval * intval;
+		if (sleepduration <= 0)
+			sleepduration = intval;
+
+#define FUDGE   2
+		/*
+		 * 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;
+		do {
+			nexttbtt += intval;
+			if (--dtimcount < 0) {
+				dtimcount = dtimperiod - 1;
+				if (--cfpcount < 0)
+					cfpcount = cfpperiod - 1;
+			}
+		} while (nexttbtt < tsftu);
+#undef FUDGE
+		memzero(&bs, sizeof(bs));
+		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 insure 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;
+
+		DPRINTF(sc, ATH_DBG_BEACON,
+			"%s: tsf %llu "
+			"tsf:tu %u "
+			"intval %u "
+			"nexttbtt %u "
+			"dtim %u "
+			"nextdtim %u "
+			"bmiss %u "
+			"sleep %u "
+			"cfp:period %u "
+			"maxdur %u "
+			"next %u "
+			"timoffset %u\n"
+			, __func__
+			, (unsigned long long)tsf, tsftu
+			, bs.bs_intval
+			, bs.bs_nexttbtt
+			, bs.bs_dtimperiod
+			, bs.bs_nextdtim
+			, bs.bs_bmissthreshold
+			, bs.bs_sleepduration
+			, bs.bs_cfpperiod
+			, bs.bs_cfpmaxduration
+			, bs.bs_cfpnext
+			, bs.bs_timoffset
+			);
+
+		ath9k_hw_set_interrupts(ah, 0);
+		ath9k_hw_set_sta_beacon_timers(ah, &bs);
+		sc->sc_imask |= ATH9K_INT_BMISS;
+		ath9k_hw_set_interrupts(ah, sc->sc_imask);
+	} else {
+		u64 tsf;
+		u32 tsftu;
+		ath9k_hw_set_interrupts(ah, 0);
+		if (nexttbtt == intval)
+			intval |= ATH9K_BEACON_RESET_TSF;
+		if (sc->sc_opmode == ATH9K_M_IBSS) {
+			/*
+			 * Pull nexttbtt forward to reflect the current
+			 * TSF .
+			 */
+#define FUDGE   2
+			if (!(intval & ATH9K_BEACON_RESET_TSF)) {
+				tsf = ath9k_hw_gettsf64(ah);
+				tsftu = TSF_TO_TU((u32)(tsf>>32),
+					(u32)tsf) + FUDGE;
+				do {
+					nexttbtt += intval;
+				} while (nexttbtt < tsftu);
+			}
+#undef FUDGE
+			DPRINTF(sc, ATH_DBG_BEACON,
+				"%s: IBSS nexttbtt %u intval %u (%u)\n",
+				__func__, nexttbtt,
+				intval & ~ATH9K_BEACON_RESET_TSF,
+				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 (!ah->ah_caps.halVEOLSupport)
+				sc->sc_imask |= ATH9K_INT_SWBA;
+			ath_beaconq_config(sc);
+		} else if (sc->sc_opmode == ATH9K_M_HOSTAP) {
+			/*
+			 * In AP mode we enable the beacon timers and
+			 * SWBA interrupts to prepare beacon frames.
+			 */
+			intval |= ATH9K_BEACON_ENA;
+			sc->sc_imask |= ATH9K_INT_SWBA;   /* beacon prepare */
+			ath_beaconq_config(sc);
+		}
+		ath9k_hw_beaconinit(ah, nexttbtt, intval);
+		sc->sc_bmisscount = 0;
+		ath9k_hw_set_interrupts(ah, sc->sc_imask);
+		/*
+		 * When using a self-linked beacon descriptor in
+		 * ibss mode load it once here.
+		 */
+		if (sc->sc_opmode == ATH9K_M_IBSS && ah->ah_caps.halVEOLSupport)
+			ath_beacon_start_adhoc(sc, 0);
+	}
+#undef TSF_TO_TU
+}
+
+/* Function to collect beacon rssi data and resync beacon if necessary */
+
+void ath_beacon_sync(struct ath_softc *sc, int if_id)
+{
+	/*
+	 * Resync beacon timers using the tsf of the
+	 * beacon frame we just received.
+	 */
+	ath_beacon_config(sc, if_id);
+	sc->sc_beacons = 1;
+}