add the new ath9k driver (loads successfully on an AR9160 card, but still seems to...
[openwrt/svn-archive/archive.git] / package / ath9k / src / drivers / net / wireless / ath9k / beacon.c
diff --git a/package/ath9k/src/drivers/net/wireless/ath9k/beacon.c b/package/ath9k/src/drivers/net/wireless/ath9k/beacon.c
new file mode 100644 (file)
index 0000000..ce99cfb
--- /dev/null
@@ -0,0 +1,1051 @@
+/*
+ * 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 "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 hal_txq_info qi;
+
+       ath9k_hw_gettxqueueprops(ah, sc->sc_bhalq, &qi);
+       if (sc->sc_opmode == HAL_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_DEBUG_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 hal_rate_table *rt;
+       u_int8_t rix, rate;
+       int ctsrate = 0;
+       int ctsduration = 0;
+       struct hal_11n_rate_series  series[4];
+
+       DPRINTF(sc, ATH_DEBUG_BEACON, "%s: m %p len %u\n",
+               __func__, skb, skb->len);
+
+       /* setup descriptors */
+       ds = bf->bf_desc;
+
+       flags = HAL_TXDESC_NOACK;
+
+       if (sc->sc_opmode == HAL_M_IBSS && sc->sc_hasveol) {
+               ds->ds_link = bf->bf_daddr; /* self-linked */
+               flags |= HAL_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
+                */
+               if (sc->sc_stagbeacons)
+                       antenna = ((sc->ast_be_xmit /
+                                       sc->sc_nbcnvaps) & 1 ? 2 : 1);
+               else
+                       antenna = (sc->ast_be_xmit & 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 */
+                             , HAL_PKT_TYPE_BEACON /* Atheros packet type */
+                             , avp->av_btxctl.txpower /* txpower XXX */
+                             , HAL_TXKEYIX_INVALID /* no encryption */
+                             , HAL_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 */
+                          , AH_TRUE /* first segment */
+                          , AH_TRUE /* last segment */
+                          , ds /* first descriptor */
+               );
+
+       memzero(series, sizeof(struct hal_11n_rate_series) * 4);
+       series[0].Tries = 1;
+       series[0].Rate = rate;
+       series[0].ChSel = sc->sc_tx_chainmask;
+       series[0].RateFlags = (ctsrate) ? HAL_RATESERIES_RTS_CTS : 0;
+       ath9k_hw_set11n_ratescenario(ah, ds, ds, 0,
+               ctsrate, ctsduration, series, 4, 0);
+
+       /* NB: The desc swap function becomes void,
+        * if descriptor swapping is not enabled
+        */
+       ath_desc_swap(ds);
+}
+
+/* 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 = cpu_to_le32(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_DEBUG_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 && sc->sc_stagbeacons) {
+                       ath_tx_draintxq(sc, cabq, AH_FALSE);
+                       DPRINTF(sc, ATH_DEBUG_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_DEBUG_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_DEBUG_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 hal_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 hal_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, HAL_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 == HAL_M_HOSTAP || !sc->sc_hasveol) {
+                       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 */
+                               }
+                       KASSERT(sc->sc_bslot[avp->av_bslot] == ATH_IF_ID_ANY,
+                               ("beacon slot %u not empty?", avp->av_bslot));
+                       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) {
+               struct ath_xmit_status tx_status;
+
+               skb = (struct sk_buff *) bf->bf_mpdu;
+               ath_skb_unmap_single(sc, skb, PCI_DMA_TODEVICE,
+                                    get_dma_mem_context(bf, bf_dmacontext));
+               tx_status.flags = 0;
+               tx_status.retries = 0;
+               ath_tx_complete(sc, skb, &tx_status, NULL);
+               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).
+        */
+       skb = ath_get_beacon(sc, if_id, &avp->av_boff, &avp->av_btxctl);
+       if (skb == NULL) {
+               DPRINTF(sc, ATH_DEBUG_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 (sc->sc_stagbeacons && avp->av_bslot > 0) {
+               u_int64_t tsfadjust;
+               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;
+               tsfadjust = cpu_to_le64(tsfadjust<<10);     /* TU->TSF */
+
+               DPRINTF(sc, ATH_DEBUG_BEACON,
+                       "%s: %s beacons, bslot %d intval %u tsfadjust %llu\n",
+                       __func__, sc->sc_stagbeacons ? "stagger" : "burst",
+                       avp->av_bslot, intval, (unsigned long long)tsfadjust);
+
+               wh = (struct ieee80211_hdr *)skb->data;
+               memcpy(&wh[1], &tsfadjust, sizeof(tsfadjust));
+       }
+
+       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;
+                       struct ath_xmit_status tx_status;
+
+                       ath_skb_unmap_single(sc, skb, PCI_DMA_TODEVICE,
+                               get_dma_mem_context(bf, bf_dmacontext));
+                       tx_status.flags = 0;
+                       tx_status.retries = 0;
+                       ath_tx_complete(sc, skb, &tx_status, NULL);
+                       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;
+                       struct ath_xmit_status tx_status;
+
+                       ath_skb_unmap_single(sc, skb, PCI_DMA_TODEVICE,
+                               get_dma_mem_context(bf, bf_dmacontext));
+                       tx_status.flags = 0;
+                       tx_status.retries = 0;
+                       ath_tx_complete(sc, skb, &tx_status, NULL);
+                       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)                                       \
+       ((((u_int32_t)(_h)) << 22) | (((u_int32_t)(_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;
+       u_int32_t bfaddr;
+       u_int32_t rx_clear = 0, rx_frame = 0, tx_frame = 0;
+       u_int32_t show_cycles = 0;
+       u_int32_t bc = 0; /* beacon count */
+
+       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_DEBUG_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_DEBUG_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_DEBUG_BEACON,
+                                               "%s: unable to obtain "
+                                               "busy times\n", __func__);
+                               }
+                       } else {
+                               DPRINTF(sc, ATH_DEBUG_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_DEBUG_BEACON,
+                                               "%s: beacon is officially "
+                                               "stuck\n", __func__);
+                                       ath9k_hw_dmaRegDump(ah);
+                               }
+                       } else {
+                               DPRINTF(sc, ATH_DEBUG_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_DEBUG_BEACON,
+                               "%s: resume beacon xmit after %u misses\n",
+                               __func__, sc->sc_bmisscount);
+               } else {
+                       DPRINTF(sc, ATH_DEBUG_BEACON,
+                               "%s: resume beacon xmit after %u misses\n",
+                               __func__, sc->sc_bmisscount);
+               }
+               sc->sc_bmisscount = 0;
+       }
+
+       /*
+        * Generate beacon frames.  If we are sending frames
+        * staggered then calculate the slot for this frame based
+        * on the tsf to safeguard against missing an swba.
+        * Otherwise we are bursting all frames together and need
+        * to generate a frame for each vap that is up and running.
+        */
+       if (sc->sc_stagbeacons) {
+               /* staggered beacons */
+               u_int64_t tsf;
+               u_int32_t tsftu;
+               u_int16_t intval;
+
+               /* 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_DEBUG_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;
+                       }
+               }
+       } else {
+               /* XXX: Clean this up, move work to a helper */
+               /* burst'd beacons */
+               u_int32_t *bflink;
+               bflink = &bfaddr;
+               /* XXX rotate/randomize order? */
+               for (slot = 0; slot < ATH_BCBUF; slot++) {
+                       if_id = sc->sc_bslot[slot];
+                       if (if_id != ATH_IF_ID_ANY) {
+                               bf = ath_beacon_generate(sc, if_id);
+                               if (bf != NULL) {
+                                       if (bflink != &bfaddr)
+                                               *bflink = cpu_to_le32(
+                                                       bf->bf_daddr);
+                                       else
+                                               *bflink = bf->bf_daddr;
+                                       bflink = &bf->bf_desc->ds_link;
+                                       bc++;
+                               }
+                       }
+               }
+               *bflink = 0;    /* link of last frame */
+       }
+       /*
+        * 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 ((!sc->sc_stagbeacons || slot == 0) && (!sc->sc_diversity)) {
+               int otherant;
+               /*
+                * Check recent per-antenna transmit statistics and flip
+                * the default rx antenna if noticeably more frames went out
+                * on the non-default antenna.  Only do this if rx diversity
+                * is off.
+                * XXX assumes 2 anntenae
+                */
+               otherant = sc->sc_defant & 1 ? 2 : 1;
+               if (sc->sc_ant_tx[otherant] > sc->sc_ant_tx[sc->sc_defant] +
+                       ATH_ANTENNA_DIFF) {
+                       DPRINTF(sc, ATH_DEBUG_BEACON,
+                               "%s: flip defant to %u, %u > %u\n",
+                               __func__, otherant, sc->sc_ant_tx[otherant],
+                               sc->sc_ant_tx[sc->sc_defant]);
+                       ath_setdefantenna(sc, otherant);
+               }
+               sc->sc_ant_tx[1] = sc->sc_ant_tx[2] = 0;
+       }
+
+       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_DEBUG_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_DEBUG_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)                                       \
+       ((((u_int32_t)(_h)) << 22) | (((u_int32_t)(_l)) >> 10))
+       struct ath_hal *ah = sc->sc_ah;
+       u_int32_t nexttbtt, intval;
+       struct ath_beacon_config conf;
+       enum hal_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(LE_READ_4(conf.u.last_tstamp + 4),
+                            LE_READ_4(conf.u.last_tstamp));
+       /* XXX conditionalize multi-bss support? */
+       if (sc->sc_opmode == HAL_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 & HAL_BEACON_PERIOD;
+               if (sc->sc_stagbeacons)
+                       intval /= ATH_BCBUF;    /* for staggered beacons */
+               if ((sc->sc_nostabeacons) &&
+                   (av_opmode == HAL_M_HOSTAP))
+                       nexttbtt = 0;
+       } else {
+               intval = conf.beacon_interval & HAL_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_DEBUG_BEACON, "%s: nexttbtt %u intval %u (%u)\n",
+               __func__, nexttbtt, intval, conf.beacon_interval);
+       /* Check for HAL_M_HOSTAP and sc_nostabeacons for WDS client */
+       if ((sc->sc_opmode == HAL_M_STA) ||
+            ((sc->sc_opmode == HAL_M_HOSTAP) &&
+             (av_opmode == HAL_M_STA) &&
+             (sc->sc_nostabeacons))) {
+               struct hal_beacon_state bs;
+               u_int64_t tsf;
+               u_int32_t 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 =
+                               howmany(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_DEBUG_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
+                       );
+
+               if (!(sc->sc_nostabeacons)) {
+                       ath9k_hw_set_interrupts(ah, 0);
+                       ath9k_hw_set_sta_beacon_timers(ah, &bs);
+                       sc->sc_imask |= HAL_INT_BMISS;
+                       ath9k_hw_set_interrupts(ah, sc->sc_imask);
+               }
+       } else {
+               u_int64_t tsf;
+               u_int32_t tsftu;
+               ath9k_hw_set_interrupts(ah, 0);
+               if (nexttbtt == intval)
+                       intval |= HAL_BEACON_RESET_TSF;
+               if (sc->sc_opmode == HAL_M_IBSS) {
+                       /*
+                        * Pull nexttbtt forward to reflect the current
+                        * TSF .
+                        */
+#define FUDGE   2
+                       if (!(intval & HAL_BEACON_RESET_TSF)) {
+                               tsf = ath9k_hw_gettsf64(ah);
+                               tsftu = TSF_TO_TU((u_int32_t)(tsf>>32),
+                                       (u_int32_t)tsf) + FUDGE;
+                               do {
+                                       nexttbtt += intval;
+                               } while (nexttbtt < tsftu);
+                       }
+#undef FUDGE
+                       DPRINTF(sc, ATH_DEBUG_BEACON,
+                               "%s: IBSS nexttbtt %u intval %u (%u)\n",
+                               __func__, nexttbtt,
+                               intval & ~HAL_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 |= HAL_BEACON_ENA;
+                       if (!sc->sc_hasveol)
+                               sc->sc_imask |= HAL_INT_SWBA;
+                       ath_beaconq_config(sc);
+               } else if (sc->sc_opmode == HAL_M_HOSTAP) {
+                       /*
+                        * In AP mode we enable the beacon timers and
+                        * SWBA interrupts to prepare beacon frames.
+                        */
+                       intval |= HAL_BEACON_ENA;
+                       sc->sc_imask |= HAL_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 == HAL_M_IBSS && sc->sc_hasveol)
+                       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;
+}