text: /*-
   * Copyright (c) 2002-2009 Sam Leffler, Errno Consulting
   * Copyright (c) 2010-2012 Adrian Chadd, Xenion Pty Ltd
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer,
   *    without modification.
   * 2. Redistributions in binary form must reproduce at minimum a disclaimer
   *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
   *    redistribution must be conditioned upon including a substantially
   *    similar Disclaimer requirement for further binary redistribution.
   *
   * NO WARRANTY
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
   * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
   * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
   * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
   * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
   * THE POSSIBILITY OF SUCH DAMAGES.
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD: head/sys/dev/ath/if_ath_tx.c 298939 2016-05-02 19:56:48Z pfg $");
  
  /*
   * Driver for the Atheros Wireless LAN controller.
   *
   * This software is derived from work of Atsushi Onoe; his contribution
   * is greatly appreciated.
   */
  
  #include "opt_inet.h"
  #include "opt_ath.h"
  #include "opt_wlan.h"
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/sysctl.h>
  #include <sys/mbuf.h>
  #include <sys/malloc.h>
  #include <sys/lock.h>
  #include <sys/mutex.h>
  #include <sys/kernel.h>
  #include <sys/socket.h>
  #include <sys/sockio.h>
  #include <sys/errno.h>
  #include <sys/callout.h>
  #include <sys/bus.h>
  #include <sys/endian.h>
  #include <sys/kthread.h>
  #include <sys/taskqueue.h>
  #include <sys/priv.h>
  #include <sys/ktr.h>
  
  #include <machine/bus.h>
  
  #include <net/if.h>
  #include <net/if_var.h>
  #include <net/if_dl.h>
  #include <net/if_media.h>
  #include <net/if_types.h>
  #include <net/if_arp.h>
  #include <net/ethernet.h>
  #include <net/if_llc.h>
  
  #include <net80211/ieee80211_var.h>
  #include <net80211/ieee80211_regdomain.h>
  #ifdef IEEE80211_SUPPORT_SUPERG
  #include <net80211/ieee80211_superg.h>
  #endif
  #ifdef IEEE80211_SUPPORT_TDMA
  #include <net80211/ieee80211_tdma.h>
  #endif
  #include <net80211/ieee80211_ht.h>
  
  #include <net/bpf.h>
  
  #ifdef INET
  #include <netinet/in.h>
  #include <netinet/if_ether.h>
  #endif
  
  #include <dev/ath/if_athvar.h>
  #include <dev/ath/ath_hal/ah_devid.h>		/* XXX for softled */
  #include <dev/ath/ath_hal/ah_diagcodes.h>
  
  #include <dev/ath/if_ath_debug.h>
  
  #ifdef ATH_TX99_DIAG
  #include <dev/ath/ath_tx99/ath_tx99.h>
  #endif
  
  #include <dev/ath/if_ath_misc.h>
  #include <dev/ath/if_ath_tx.h>
  #include <dev/ath/if_ath_tx_ht.h>
  
  #ifdef	ATH_DEBUG_ALQ
  #include <dev/ath/if_ath_alq.h>
  #endif
  
  /*
   * How many retries to perform in software
   */
  #define	SWMAX_RETRIES		10
  
  /*
   * What queue to throw the non-QoS TID traffic into
   */
  #define	ATH_NONQOS_TID_AC	WME_AC_VO
  
  #if 0
  static int ath_tx_node_is_asleep(struct ath_softc *sc, struct ath_node *an);
  #endif
  static int ath_tx_ampdu_pending(struct ath_softc *sc, struct ath_node *an,
      int tid);
  static int ath_tx_ampdu_running(struct ath_softc *sc, struct ath_node *an,
      int tid);
  static ieee80211_seq ath_tx_tid_seqno_assign(struct ath_softc *sc,
      struct ieee80211_node *ni, struct ath_buf *bf, struct mbuf *m0);
  static int ath_tx_action_frame_override_queue(struct ath_softc *sc,
      struct ieee80211_node *ni, struct mbuf *m0, int *tid);
  static struct ath_buf *
  ath_tx_retry_clone(struct ath_softc *sc, struct ath_node *an,
      struct ath_tid *tid, struct ath_buf *bf);
  
  #ifdef	ATH_DEBUG_ALQ
  void
  ath_tx_alq_post(struct ath_softc *sc, struct ath_buf *bf_first)
  {
  	struct ath_buf *bf;
  	int i, n;
  	const char *ds;
  
  	/* XXX we should skip out early if debugging isn't enabled! */
  	bf = bf_first;
  
  	while (bf != NULL) {
  		/* XXX should ensure bf_nseg > 0! */
  		if (bf->bf_nseg == 0)
  			break;
  		n = ((bf->bf_nseg - 1) / sc->sc_tx_nmaps) + 1;
  		for (i = 0, ds = (const char *) bf->bf_desc;
  		    i < n;
  		    i++, ds += sc->sc_tx_desclen) {
  			if_ath_alq_post(&sc->sc_alq,
  			    ATH_ALQ_EDMA_TXDESC,
  			    sc->sc_tx_desclen,
  			    ds);
  		}
  		bf = bf->bf_next;
  	}
  }
  #endif /* ATH_DEBUG_ALQ */
  
  /*
   * Whether to use the 11n rate scenario functions or not
   */
  static inline int
  ath_tx_is_11n(struct ath_softc *sc)
  {
  	return ((sc->sc_ah->ah_magic == 0x20065416) ||
  		    (sc->sc_ah->ah_magic == 0x19741014));
  }
  
  /*
   * Obtain the current TID from the given frame.
   *
   * Non-QoS frames need to go into TID 16 (IEEE80211_NONQOS_TID.)
   * This has implications for which AC/priority the packet is placed
   * in.
   */
  static int
  ath_tx_gettid(struct ath_softc *sc, const struct mbuf *m0)
  {
  	const struct ieee80211_frame *wh;
  	int pri = M_WME_GETAC(m0);
  
  	wh = mtod(m0, const struct ieee80211_frame *);
  	if (! IEEE80211_QOS_HAS_SEQ(wh))
  		return IEEE80211_NONQOS_TID;
  	else
  		return WME_AC_TO_TID(pri);
  }
  
  static void
  ath_tx_set_retry(struct ath_softc *sc, struct ath_buf *bf)
  {
  	struct ieee80211_frame *wh;
  
  	wh = mtod(bf->bf_m, struct ieee80211_frame *);
  	/* Only update/resync if needed */
  	if (bf->bf_state.bfs_isretried == 0) {
  		wh->i_fc[1] |= IEEE80211_FC1_RETRY;
  		bus_dmamap_sync(sc->sc_dmat, bf->bf_dmamap,
  		    BUS_DMASYNC_PREWRITE);
  	}
  	bf->bf_state.bfs_isretried = 1;
  	bf->bf_state.bfs_retries ++;
  }
  
  /*
   * Determine what the correct AC queue for the given frame
   * should be.
   *
   * This code assumes that the TIDs map consistently to
   * the underlying hardware (or software) ath_txq.
   * Since the sender may try to set an AC which is
   * arbitrary, non-QoS TIDs may end up being put on
   * completely different ACs. There's no way to put a
   * TID into multiple ath_txq's for scheduling, so
   * for now we override the AC/TXQ selection and set
   * non-QOS TID frames into the BE queue.
   *
   * This may be completely incorrect - specifically,
   * some management frames may end up out of order
   * compared to the QoS traffic they're controlling.
   * I'll look into this later.
   */
  static int
  ath_tx_getac(struct ath_softc *sc, const struct mbuf *m0)
  {
  	const struct ieee80211_frame *wh;
  	int pri = M_WME_GETAC(m0);
  	wh = mtod(m0, const struct ieee80211_frame *);
  	if (IEEE80211_QOS_HAS_SEQ(wh))
  		return pri;
  
  	return ATH_NONQOS_TID_AC;
  }
  
  void
  ath_txfrag_cleanup(struct ath_softc *sc,
  	ath_bufhead *frags, struct ieee80211_node *ni)
  {
  	struct ath_buf *bf, *next;
  
  	ATH_TXBUF_LOCK_ASSERT(sc);
  
  	TAILQ_FOREACH_SAFE(bf, frags, bf_list, next) {
  		/* NB: bf assumed clean */
  		TAILQ_REMOVE(frags, bf, bf_list);
  		ath_returnbuf_head(sc, bf);
  		ieee80211_node_decref(ni);
  	}
  }
  
  /*
   * Setup xmit of a fragmented frame.  Allocate a buffer
   * for each frag and bump the node reference count to
   * reflect the held reference to be setup by ath_tx_start.
   */
  int
  ath_txfrag_setup(struct ath_softc *sc, ath_bufhead *frags,
  	struct mbuf *m0, struct ieee80211_node *ni)
  {
  	struct mbuf *m;
  	struct ath_buf *bf;
  
  	ATH_TXBUF_LOCK(sc);
  	for (m = m0->m_nextpkt; m != NULL; m = m->m_nextpkt) {
  		/* XXX non-management? */
  		bf = _ath_getbuf_locked(sc, ATH_BUFTYPE_NORMAL);
  		if (bf == NULL) {	/* out of buffers, cleanup */
  			DPRINTF(sc, ATH_DEBUG_XMIT, "%s: no buffer?\n",
  			    __func__);
  			ath_txfrag_cleanup(sc, frags, ni);
  			break;
  		}
  		ieee80211_node_incref(ni);
  		TAILQ_INSERT_TAIL(frags, bf, bf_list);
  	}
  	ATH_TXBUF_UNLOCK(sc);
  
  	return !TAILQ_EMPTY(frags);
  }
  
  static int
  ath_tx_dmasetup(struct ath_softc *sc, struct ath_buf *bf, struct mbuf *m0)
  {
  	struct mbuf *m;
  	int error;
  
  	/*
  	 * Load the DMA map so any coalescing is done.  This
  	 * also calculates the number of descriptors we need.
  	 */
  	error = bus_dmamap_load_mbuf_sg(sc->sc_dmat, bf->bf_dmamap, m0,
  				     bf->bf_segs, &bf->bf_nseg,
  				     BUS_DMA_NOWAIT);
  	if (error == EFBIG) {
  		/* XXX packet requires too many descriptors */
  		bf->bf_nseg = ATH_MAX_SCATTER + 1;
  	} else if (error != 0) {
  		sc->sc_stats.ast_tx_busdma++;
  		ieee80211_free_mbuf(m0);
  		return error;
  	}
  	/*
  	 * Discard null packets and check for packets that
  	 * require too many TX descriptors.  We try to convert
  	 * the latter to a cluster.
  	 */
  	if (bf->bf_nseg > ATH_MAX_SCATTER) {		/* too many desc's, linearize */
  		sc->sc_stats.ast_tx_linear++;
  		m = m_collapse(m0, M_NOWAIT, ATH_MAX_SCATTER);
  		if (m == NULL) {
  			ieee80211_free_mbuf(m0);
  			sc->sc_stats.ast_tx_nombuf++;
  			return ENOMEM;
  		}
  		m0 = m;
  		error = bus_dmamap_load_mbuf_sg(sc->sc_dmat, bf->bf_dmamap, m0,
  					     bf->bf_segs, &bf->bf_nseg,
  					     BUS_DMA_NOWAIT);
  		if (error != 0) {
  			sc->sc_stats.ast_tx_busdma++;
  			ieee80211_free_mbuf(m0);
  			return error;
  		}
  		KASSERT(bf->bf_nseg <= ATH_MAX_SCATTER,
  		    ("too many segments after defrag; nseg %u", bf->bf_nseg));
  	} else if (bf->bf_nseg == 0) {		/* null packet, discard */
  		sc->sc_stats.ast_tx_nodata++;
  		ieee80211_free_mbuf(m0);
  		return EIO;
  	}
  	DPRINTF(sc, ATH_DEBUG_XMIT, "%s: m %p len %u\n",
  		__func__, m0, m0->m_pkthdr.len);
  	bus_dmamap_sync(sc->sc_dmat, bf->bf_dmamap, BUS_DMASYNC_PREWRITE);
  	bf->bf_m = m0;
  
  	return 0;
  }
  
  /*
   * Chain together segments+descriptors for a frame - 11n or otherwise.
   *
   * For aggregates, this is called on each frame in the aggregate.
   */
  static void
  ath_tx_chaindesclist(struct ath_softc *sc, struct ath_desc *ds0,
      struct ath_buf *bf, int is_aggr, int is_first_subframe,
      int is_last_subframe)
  {
  	struct ath_hal *ah = sc->sc_ah;
  	char *ds;
  	int i, bp, dsp;
  	HAL_DMA_ADDR bufAddrList[4];
  	uint32_t segLenList[4];
  	int numTxMaps = 1;
  	int isFirstDesc = 1;
  
  	/*
  	 * XXX There's txdma and txdma_mgmt; the descriptor
  	 * sizes must match.
  	 */
  	struct ath_descdma *dd = &sc->sc_txdma;
  
  	/*
  	 * Fillin the remainder of the descriptor info.
  	 */
  
  	/*
  	 * We need the number of TX data pointers in each descriptor.
  	 * EDMA and later chips support 4 TX buffers per descriptor;
  	 * previous chips just support one.
  	 */
  	numTxMaps = sc->sc_tx_nmaps;
  
  	/*
  	 * For EDMA and later chips ensure the TX map is fully populated
  	 * before advancing to the next descriptor.
  	 */
  	ds = (char *) bf->bf_desc;
  	bp = dsp = 0;
  	bzero(bufAddrList, sizeof(bufAddrList));
  	bzero(segLenList, sizeof(segLenList));
  	for (i = 0; i < bf->bf_nseg; i++) {
  		bufAddrList[bp] = bf->bf_segs[i].ds_addr;
  		segLenList[bp] = bf->bf_segs[i].ds_len;
  		bp++;
  
  		/*
  		 * Go to the next segment if this isn't the last segment
  		 * and there's space in the current TX map.
  		 */
  		if ((i != bf->bf_nseg - 1) && (bp < numTxMaps))
  			continue;
  
  		/*
  		 * Last segment or we're out of buffer pointers.
  		 */
  		bp = 0;
  
  		if (i == bf->bf_nseg - 1)
  			ath_hal_settxdesclink(ah, (struct ath_desc *) ds, 0);
  		else
  			ath_hal_settxdesclink(ah, (struct ath_desc *) ds,
  			    bf->bf_daddr + dd->dd_descsize * (dsp + 1));
  
  		/*
  		 * XXX This assumes that bfs_txq is the actual destination
  		 * hardware queue at this point.  It may not have been
  		 * assigned, it may actually be pointing to the multicast
  		 * software TXQ id.  These must be fixed!
  		 */
  		ath_hal_filltxdesc(ah, (struct ath_desc *) ds
  			, bufAddrList
  			, segLenList
  			, bf->bf_descid		/* XXX desc id */
  			, bf->bf_state.bfs_tx_queue
  			, isFirstDesc		/* first segment */
  			, i == bf->bf_nseg - 1	/* last segment */
  			, (struct ath_desc *) ds0	/* first descriptor */
  		);
  
  		/*
  		 * Make sure the 11n aggregate fields are cleared.
  		 *
  		 * XXX TODO: this doesn't need to be called for
  		 * aggregate frames; as it'll be called on all
  		 * sub-frames.  Since the descriptors are in
  		 * non-cacheable memory, this leads to some
  		 * rather slow writes on MIPS/ARM platforms.
  		 */
  		if (ath_tx_is_11n(sc))
  			ath_hal_clr11n_aggr(sc->sc_ah, (struct ath_desc *) ds);
  
  		/*
  		 * If 11n is enabled, set it up as if it's an aggregate
  		 * frame.
  		 */
  		if (is_last_subframe) {
  			ath_hal_set11n_aggr_last(sc->sc_ah,
  			    (struct ath_desc *) ds);
  		} else if (is_aggr) {
  			/*
  			 * This clears the aggrlen field; so
  			 * the caller needs to call set_aggr_first()!
  			 *
  			 * XXX TODO: don't call this for the first
  			 * descriptor in the first frame in an
  			 * aggregate!
  			 */
  			ath_hal_set11n_aggr_middle(sc->sc_ah,
  			    (struct ath_desc *) ds,
  			    bf->bf_state.bfs_ndelim);
  		}
  		isFirstDesc = 0;
  		bf->bf_lastds = (struct ath_desc *) ds;
  
  		/*
  		 * Don't forget to skip to the next descriptor.
  		 */
  		ds += sc->sc_tx_desclen;
  		dsp++;
  
  		/*
  		 * .. and don't forget to blank these out!
  		 */
  		bzero(bufAddrList, sizeof(bufAddrList));
  		bzero(segLenList, sizeof(segLenList));
  	}
  	bus_dmamap_sync(sc->sc_dmat, bf->bf_dmamap, BUS_DMASYNC_PREWRITE);
  }
  
  /*
   * Set the rate control fields in the given descriptor based on
   * the bf_state fields and node state.
   *
   * The bfs fields should already be set with the relevant rate
   * control information, including whether MRR is to be enabled.
   *
   * Since the FreeBSD HAL currently sets up the first TX rate
   * in ath_hal_setuptxdesc(), this will setup the MRR
   * conditionally for the pre-11n chips, and call ath_buf_set_rate
   * unconditionally for 11n chips. These require the 11n rate
   * scenario to be set if MCS rates are enabled, so it's easier
   * to just always call it. The caller can then only set rates 2, 3
   * and 4 if multi-rate retry is needed.
   */
  static void
  ath_tx_set_ratectrl(struct ath_softc *sc, struct ieee80211_node *ni,
      struct ath_buf *bf)
  {
  	struct ath_rc_series *rc = bf->bf_state.bfs_rc;
  
  	/* If mrr is disabled, blank tries 1, 2, 3 */
  	if (! bf->bf_state.bfs_ismrr)
  		rc[1].tries = rc[2].tries = rc[3].tries = 0;
  
  #if 0
  	/*
  	 * If NOACK is set, just set ntries=1.
  	 */
  	else if (bf->bf_state.bfs_txflags & HAL_TXDESC_NOACK) {
  		rc[1].tries = rc[2].tries = rc[3].tries = 0;
  		rc[0].tries = 1;
  	}
  #endif
  
  	/*
  	 * Always call - that way a retried descriptor will
  	 * have the MRR fields overwritten.
  	 *
  	 * XXX TODO: see if this is really needed - setting up
  	 * the first descriptor should set the MRR fields to 0
  	 * for us anyway.
  	 */
  	if (ath_tx_is_11n(sc)) {
  		ath_buf_set_rate(sc, ni, bf);
  	} else {
  		ath_hal_setupxtxdesc(sc->sc_ah, bf->bf_desc
  			, rc[1].ratecode, rc[1].tries
  			, rc[2].ratecode, rc[2].tries
  			, rc[3].ratecode, rc[3].tries
  		);
  	}
  }
  
  /*
   * Setup segments+descriptors for an 11n aggregate.
   * bf_first is the first buffer in the aggregate.
   * The descriptor list must already been linked together using
   * bf->bf_next.
   */
  static void
  ath_tx_setds_11n(struct ath_softc *sc, struct ath_buf *bf_first)
  {
  	struct ath_buf *bf, *bf_prev = NULL;
  	struct ath_desc *ds0 = bf_first->bf_desc;
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR, "%s: nframes=%d, al=%d\n",
  	    __func__, bf_first->bf_state.bfs_nframes,
  	    bf_first->bf_state.bfs_al);
  
  	bf = bf_first;
  
  	if (bf->bf_state.bfs_txrate0 == 0)
  		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR, "%s: bf=%p, txrate0=%d\n",
  		    __func__, bf, 0);
  	if (bf->bf_state.bfs_rc[0].ratecode == 0)
  		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR, "%s: bf=%p, rix0=%d\n",
  		    __func__, bf, 0);
  
  	/*
  	 * Setup all descriptors of all subframes - this will
  	 * call ath_hal_set11naggrmiddle() on every frame.
  	 */
  	while (bf != NULL) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  		    "%s: bf=%p, nseg=%d, pktlen=%d, seqno=%d\n",
  		    __func__, bf, bf->bf_nseg, bf->bf_state.bfs_pktlen,
  		    SEQNO(bf->bf_state.bfs_seqno));
  
  		/*
  		 * Setup the initial fields for the first descriptor - all
  		 * the non-11n specific stuff.
  		 */
  		ath_hal_setuptxdesc(sc->sc_ah, bf->bf_desc
  			, bf->bf_state.bfs_pktlen	/* packet length */
  			, bf->bf_state.bfs_hdrlen	/* header length */
  			, bf->bf_state.bfs_atype	/* Atheros packet type */
  			, bf->bf_state.bfs_txpower	/* txpower */
  			, bf->bf_state.bfs_txrate0
  			, bf->bf_state.bfs_try0		/* series 0 rate/tries */
  			, bf->bf_state.bfs_keyix	/* key cache index */
  			, bf->bf_state.bfs_txantenna	/* antenna mode */
  			, bf->bf_state.bfs_txflags | HAL_TXDESC_INTREQ	/* flags */
  			, bf->bf_state.bfs_ctsrate	/* rts/cts rate */
  			, bf->bf_state.bfs_ctsduration	/* rts/cts duration */
  		);
  
  		/*
  		 * First descriptor? Setup the rate control and initial
  		 * aggregate header information.
  		 */
  		if (bf == bf_first) {
  			/*
  			 * setup first desc with rate and aggr info
  			 */
  			ath_tx_set_ratectrl(sc, bf->bf_node, bf);
  		}
  
  		/*
  		 * Setup the descriptors for a multi-descriptor frame.
  		 * This is both aggregate and non-aggregate aware.
  		 */
  		ath_tx_chaindesclist(sc, ds0, bf,
  		    1, /* is_aggr */
  		    !! (bf == bf_first), /* is_first_subframe */
  		    !! (bf->bf_next == NULL) /* is_last_subframe */
  		    );
  
  		if (bf == bf_first) {
  			/*
  			 * Initialise the first 11n aggregate with the
  			 * aggregate length and aggregate enable bits.
  			 */
  			ath_hal_set11n_aggr_first(sc->sc_ah,
  			    ds0,
  			    bf->bf_state.bfs_al,
  			    bf->bf_state.bfs_ndelim);
  		}
  
  		/*
  		 * Link the last descriptor of the previous frame
  		 * to the beginning descriptor of this frame.
  		 */
  		if (bf_prev != NULL)
  			ath_hal_settxdesclink(sc->sc_ah, bf_prev->bf_lastds,
  			    bf->bf_daddr);
  
  		/* Save a copy so we can link the next descriptor in */
  		bf_prev = bf;
  		bf = bf->bf_next;
  	}
  
  	/*
  	 * Set the first descriptor bf_lastds field to point to
  	 * the last descriptor in the last subframe, that's where
  	 * the status update will occur.
  	 */
  	bf_first->bf_lastds = bf_prev->bf_lastds;
  
  	/*
  	 * And bf_last in the first descriptor points to the end of
  	 * the aggregate list.
  	 */
  	bf_first->bf_last = bf_prev;
  
  	/*
  	 * For non-AR9300 NICs, which require the rate control
  	 * in the final descriptor - let's set that up now.
  	 *
  	 * This is because the filltxdesc() HAL call doesn't
  	 * populate the last segment with rate control information
  	 * if firstSeg is also true.  For non-aggregate frames
  	 * that is fine, as the first frame already has rate control
  	 * info.  But if the last frame in an aggregate has one
  	 * descriptor, both firstseg and lastseg will be true and
  	 * the rate info isn't copied.
  	 *
  	 * This is inefficient on MIPS/ARM platforms that have
  	 * non-cachable memory for TX descriptors, but we'll just
  	 * make do for now.
  	 *
  	 * As to why the rate table is stashed in the last descriptor
  	 * rather than the first descriptor?  Because proctxdesc()
  	 * is called on the final descriptor in an MPDU or A-MPDU -
  	 * ie, the one that gets updated by the hardware upon
  	 * completion.  That way proctxdesc() doesn't need to know
  	 * about the first _and_ last TX descriptor.
  	 */
  	ath_hal_setuplasttxdesc(sc->sc_ah, bf_prev->bf_lastds, ds0);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR, "%s: end\n", __func__);
  }
  
  /*
   * Hand-off a frame to the multicast TX queue.
   *
   * This is a software TXQ which will be appended to the CAB queue
   * during the beacon setup code.
   *
   * XXX TODO: since the AR9300 EDMA TX queue support wants the QCU ID
   * as part of the TX descriptor, bf_state.bfs_tx_queue must be updated
   * with the actual hardware txq, or all of this will fall apart.
   *
   * XXX It may not be a bad idea to just stuff the QCU ID into bf_state
   * and retire bfs_tx_queue; then make sure the CABQ QCU ID is populated
   * correctly.
   */
  static void
  ath_tx_handoff_mcast(struct ath_softc *sc, struct ath_txq *txq,
      struct ath_buf *bf)
  {
  	ATH_TX_LOCK_ASSERT(sc);
  
  	KASSERT((bf->bf_flags & ATH_BUF_BUSY) == 0,
  	     ("%s: busy status 0x%x", __func__, bf->bf_flags));
  
  	/*
  	 * Ensure that the tx queue is the cabq, so things get
  	 * mapped correctly.
  	 */
  	if (bf->bf_state.bfs_tx_queue != sc->sc_cabq->axq_qnum) {
  		DPRINTF(sc, ATH_DEBUG_XMIT,
  		    "%s: bf=%p, bfs_tx_queue=%d, axq_qnum=%d\n",
  		    __func__, bf, bf->bf_state.bfs_tx_queue,
  		    txq->axq_qnum);
  	}
  
  	ATH_TXQ_LOCK(txq);
  	if (ATH_TXQ_LAST(txq, axq_q_s) != NULL) {
  		struct ath_buf *bf_last = ATH_TXQ_LAST(txq, axq_q_s);
  		struct ieee80211_frame *wh;
  
  		/* mark previous frame */
  		wh = mtod(bf_last->bf_m, struct ieee80211_frame *);
  		wh->i_fc[1] |= IEEE80211_FC1_MORE_DATA;
  		bus_dmamap_sync(sc->sc_dmat, bf_last->bf_dmamap,
  		    BUS_DMASYNC_PREWRITE);
  
  		/* link descriptor */
  		ath_hal_settxdesclink(sc->sc_ah,
  		    bf_last->bf_lastds,
  		    bf->bf_daddr);
  	}
  	ATH_TXQ_INSERT_TAIL(txq, bf, bf_list);
  	ATH_TXQ_UNLOCK(txq);
  }
  
  /*
   * Hand-off packet to a hardware queue.
   */
  static void
  ath_tx_handoff_hw(struct ath_softc *sc, struct ath_txq *txq,
      struct ath_buf *bf)
  {
  	struct ath_hal *ah = sc->sc_ah;
  	struct ath_buf *bf_first;
  
  	/*
  	 * Insert the frame on the outbound list and pass it on
  	 * to the hardware.  Multicast frames buffered for power
  	 * save stations and transmit from the CAB queue are stored
  	 * on a s/w only queue and loaded on to the CAB queue in
  	 * the SWBA handler since frames only go out on DTIM and
  	 * to avoid possible races.
  	 */
  	ATH_TX_LOCK_ASSERT(sc);
  	KASSERT((bf->bf_flags & ATH_BUF_BUSY) == 0,
  	     ("%s: busy status 0x%x", __func__, bf->bf_flags));
  	KASSERT(txq->axq_qnum != ATH_TXQ_SWQ,
  	     ("ath_tx_handoff_hw called for mcast queue"));
  
  	/*
  	 * XXX We should instead just verify that sc_txstart_cnt
  	 * or ath_txproc_cnt > 0.  That would mean that
  	 * the reset is going to be waiting for us to complete.
  	 */
  	if (sc->sc_txproc_cnt == 0 && sc->sc_txstart_cnt == 0) {
  		device_printf(sc->sc_dev,
  		    "%s: TX dispatch without holding txcount/txstart refcnt!\n",
  		    __func__);
  	}
  
  	/*
  	 * XXX .. this is going to cause the hardware to get upset;
  	 * so we really should find some way to drop or queue
  	 * things.
  	 */
  
  	ATH_TXQ_LOCK(txq);
  
  	/*
  	 * XXX TODO: if there's a holdingbf, then
  	 * ATH_TXQ_PUTRUNNING should be clear.
  	 *
  	 * If there is a holdingbf and the list is empty,
  	 * then axq_link should be pointing to the holdingbf.
  	 *
  	 * Otherwise it should point to the last descriptor
  	 * in the last ath_buf.
  	 *
  	 * In any case, we should really ensure that we
  	 * update the previous descriptor link pointer to
  	 * this descriptor, regardless of all of the above state.
  	 *
  	 * For now this is captured by having axq_link point
  	 * to either the holdingbf (if the TXQ list is empty)
  	 * or the end of the list (if the TXQ list isn't empty.)
  	 * I'd rather just kill axq_link here and do it as above.
  	 */
  
  	/*
  	 * Append the frame to the TX queue.
  	 */
  	ATH_TXQ_INSERT_TAIL(txq, bf, bf_list);
  	ATH_KTR(sc, ATH_KTR_TX, 3,
  	    "ath_tx_handoff: non-tdma: txq=%u, add bf=%p "
  	    "depth=%d",
  	    txq->axq_qnum,
  	    bf,
  	    txq->axq_depth);
  
  	/*
  	 * If there's a link pointer, update it.
  	 *
  	 * XXX we should replace this with the above logic, just
  	 * to kill axq_link with fire.
  	 */
  	if (txq->axq_link != NULL) {
  		*txq->axq_link = bf->bf_daddr;
  		DPRINTF(sc, ATH_DEBUG_XMIT,
  		    "%s: link[%u](%p)=%p (%p) depth %d\n", __func__,
  		    txq->axq_qnum, txq->axq_link,
  		    (caddr_t)bf->bf_daddr, bf->bf_desc,
  		    txq->axq_depth);
  		ATH_KTR(sc, ATH_KTR_TX, 5,
  		    "ath_tx_handoff: non-tdma: link[%u](%p)=%p (%p) "
  		    "lastds=%d",
  		    txq->axq_qnum, txq->axq_link,
  		    (caddr_t)bf->bf_daddr, bf->bf_desc,
  		    bf->bf_lastds);
  	}
  
  	/*
  	 * If we've not pushed anything into the hardware yet,
  	 * push the head of the queue into the TxDP.
  	 *
  	 * Once we've started DMA, there's no guarantee that
  	 * updating the TxDP with a new value will actually work.
  	 * So we just don't do that - if we hit the end of the list,
  	 * we keep that buffer around (the "holding buffer") and
  	 * re-start DMA by updating the link pointer of _that_
  	 * descriptor and then restart DMA.
  	 */
  	if (! (txq->axq_flags & ATH_TXQ_PUTRUNNING)) {
  		bf_first = TAILQ_FIRST(&txq->axq_q);
  		txq->axq_flags |= ATH_TXQ_PUTRUNNING;
  		ath_hal_puttxbuf(ah, txq->axq_qnum, bf_first->bf_daddr);
  		DPRINTF(sc, ATH_DEBUG_XMIT,
  		    "%s: TXDP[%u] = %p (%p) depth %d\n",
  		    __func__, txq->axq_qnum,
  		    (caddr_t)bf_first->bf_daddr, bf_first->bf_desc,
  		    txq->axq_depth);
  		ATH_KTR(sc, ATH_KTR_TX, 5,
  		    "ath_tx_handoff: TXDP[%u] = %p (%p) "
  		    "lastds=%p depth %d",
  		    txq->axq_qnum,
  		    (caddr_t)bf_first->bf_daddr, bf_first->bf_desc,
  		    bf_first->bf_lastds,
  		    txq->axq_depth);
  	}
  
  	/*
  	 * Ensure that the bf TXQ matches this TXQ, so later
  	 * checking and holding buffer manipulation is sane.
  	 */
  	if (bf->bf_state.bfs_tx_queue != txq->axq_qnum) {
  		DPRINTF(sc, ATH_DEBUG_XMIT,
  		    "%s: bf=%p, bfs_tx_queue=%d, axq_qnum=%d\n",
  		    __func__, bf, bf->bf_state.bfs_tx_queue,
  		    txq->axq_qnum);
  	}
  
  	/*
  	 * Track aggregate queue depth.
  	 */
  	if (bf->bf_state.bfs_aggr)
  		txq->axq_aggr_depth++;
  
  	/*
  	 * Update the link pointer.
  	 */
  	ath_hal_gettxdesclinkptr(ah, bf->bf_lastds, &txq->axq_link);
  
  	/*
  	 * Start DMA.
  	 *
  	 * If we wrote a TxDP above, DMA will start from here.
  	 *
  	 * If DMA is running, it'll do nothing.
  	 *
  	 * If the DMA engine hit the end of the QCU list (ie LINK=NULL,
  	 * or VEOL) then it stops at the last transmitted write.
  	 * We then append a new frame by updating the link pointer
  	 * in that descriptor and then kick TxE here; it will re-read
  	 * that last descriptor and find the new descriptor to transmit.
  	 *
  	 * This is why we keep the holding descriptor around.
  	 */
  	ath_hal_txstart(ah, txq->axq_qnum);
  	ATH_TXQ_UNLOCK(txq);
  	ATH_KTR(sc, ATH_KTR_TX, 1,
  	    "ath_tx_handoff: txq=%u, txstart", txq->axq_qnum);
  }
  
  /*
   * Restart TX DMA for the given TXQ.
   *
   * This must be called whether the queue is empty or not.
   */
  static void
  ath_legacy_tx_dma_restart(struct ath_softc *sc, struct ath_txq *txq)
  {
  	struct ath_buf *bf, *bf_last;
  
  	ATH_TXQ_LOCK_ASSERT(txq);
  
  	/* XXX make this ATH_TXQ_FIRST */
  	bf = TAILQ_FIRST(&txq->axq_q);
  	bf_last = ATH_TXQ_LAST(txq, axq_q_s);
  
  	if (bf == NULL)
  		return;
  
  	DPRINTF(sc, ATH_DEBUG_RESET,
  	    "%s: Q%d: bf=%p, bf_last=%p, daddr=0x%08x\n",
  	    __func__,
  	    txq->axq_qnum,
  	    bf,
  	    bf_last,
  	    (uint32_t) bf->bf_daddr);
  
  #ifdef	ATH_DEBUG
  	if (sc->sc_debug & ATH_DEBUG_RESET)
  		ath_tx_dump(sc, txq);
  #endif
  
  	/*
  	 * This is called from a restart, so DMA is known to be
  	 * completely stopped.
  	 */
  	KASSERT((!(txq->axq_flags & ATH_TXQ_PUTRUNNING)),
  	    ("%s: Q%d: called with PUTRUNNING=1\n",
  	    __func__,
  	    txq->axq_qnum));
  
  	ath_hal_puttxbuf(sc->sc_ah, txq->axq_qnum, bf->bf_daddr);
  	txq->axq_flags |= ATH_TXQ_PUTRUNNING;
  
  	ath_hal_gettxdesclinkptr(sc->sc_ah, bf_last->bf_lastds,
  	    &txq->axq_link);
  	ath_hal_txstart(sc->sc_ah, txq->axq_qnum);
  }
  
  /*
   * Hand off a packet to the hardware (or mcast queue.)
   *
   * The relevant hardware txq should be locked.
   */
  static void
  ath_legacy_xmit_handoff(struct ath_softc *sc, struct ath_txq *txq,
      struct ath_buf *bf)
  {
  	ATH_TX_LOCK_ASSERT(sc);
  
  #ifdef	ATH_DEBUG_ALQ
  	if (if_ath_alq_checkdebug(&sc->sc_alq, ATH_ALQ_EDMA_TXDESC))
  		ath_tx_alq_post(sc, bf);
  #endif
  
  	if (txq->axq_qnum == ATH_TXQ_SWQ)
  		ath_tx_handoff_mcast(sc, txq, bf);
  	else
  		ath_tx_handoff_hw(sc, txq, bf);
  }
  
  static int
  ath_tx_tag_crypto(struct ath_softc *sc, struct ieee80211_node *ni,
      struct mbuf *m0, int iswep, int isfrag, int *hdrlen, int *pktlen,
      int *keyix)
  {
  	DPRINTF(sc, ATH_DEBUG_XMIT,
  	    "%s: hdrlen=%d, pktlen=%d, isfrag=%d, iswep=%d, m0=%p\n",
  	    __func__,
  	    *hdrlen,
  	    *pktlen,
  	    isfrag,
  	    iswep,
  	    m0);
  
  	if (iswep) {
  		const struct ieee80211_cipher *cip;
  		struct ieee80211_key *k;
  
  		/*
  		 * Construct the 802.11 header+trailer for an encrypted
  		 * frame. The only reason this can fail is because of an
  		 * unknown or unsupported cipher/key type.
  		 */
  		k = ieee80211_crypto_encap(ni, m0);
  		if (k == NULL) {
  			/*
  			 * This can happen when the key is yanked after the
  			 * frame was queued.  Just discard the frame; the
  			 * 802.11 layer counts failures and provides
  			 * debugging/diagnostics.
  			 */
  			return (0);
  		}
  		/*
  		 * Adjust the packet + header lengths for the crypto
  		 * additions and calculate the h/w key index.  When
  		 * a s/w mic is done the frame will have had any mic
  		 * added to it prior to entry so m0->m_pkthdr.len will
  		 * account for it. Otherwise we need to add it to the
  		 * packet length.
  		 */
  		cip = k->wk_cipher;
  		(*hdrlen) += cip->ic_header;
  		(*pktlen) += cip->ic_header + cip->ic_trailer;
  		/* NB: frags always have any TKIP MIC done in s/w */
  		if ((k->wk_flags & IEEE80211_KEY_SWMIC) == 0 && !isfrag)
  			(*pktlen) += cip->ic_miclen;
  		(*keyix) = k->wk_keyix;
  	} else if (ni->ni_ucastkey.wk_cipher == &ieee80211_cipher_none) {
  		/*
  		 * Use station key cache slot, if assigned.
  		 */
  		(*keyix) = ni->ni_ucastkey.wk_keyix;
  		if ((*keyix) == IEEE80211_KEYIX_NONE)
  			(*keyix) = HAL_TXKEYIX_INVALID;
  	} else
  		(*keyix) = HAL_TXKEYIX_INVALID;
  
  	return (1);
  }
  
  /*
   * Calculate whether interoperability protection is required for
   * this frame.
   *
   * This requires the rate control information be filled in,
   * as the protection requirement depends upon the current
   * operating mode / PHY.
   */
  static void
  ath_tx_calc_protection(struct ath_softc *sc, struct ath_buf *bf)
  {
  	struct ieee80211_frame *wh;
  	uint8_t rix;
  	uint16_t flags;
  	int shortPreamble;
  	const HAL_RATE_TABLE *rt = sc->sc_currates;
  	struct ieee80211com *ic = &sc->sc_ic;
  
  	flags = bf->bf_state.bfs_txflags;
  	rix = bf->bf_state.bfs_rc[0].rix;
  	shortPreamble = bf->bf_state.bfs_shpream;
  	wh = mtod(bf->bf_m, struct ieee80211_frame *);
  
  	/*
  	 * If 802.11g protection is enabled, determine whether
  	 * to use RTS/CTS or just CTS.  Note that this is only
  	 * done for OFDM unicast frames.
  	 */
  	if ((ic->ic_flags & IEEE80211_F_USEPROT) &&
  	    rt->info[rix].phy == IEEE80211_T_OFDM &&
  	    (flags & HAL_TXDESC_NOACK) == 0) {
  		bf->bf_state.bfs_doprot = 1;
  		/* XXX fragments must use CCK rates w/ protection */
  		if (ic->ic_protmode == IEEE80211_PROT_RTSCTS) {
  			flags |= HAL_TXDESC_RTSENA;
  		} else if (ic->ic_protmode == IEEE80211_PROT_CTSONLY) {
  			flags |= HAL_TXDESC_CTSENA;
  		}
  		/*
  		 * For frags it would be desirable to use the
  		 * highest CCK rate for RTS/CTS.  But stations
  		 * farther away may detect it at a lower CCK rate
  		 * so use the configured protection rate instead
  		 * (for now).
  		 */
  		sc->sc_stats.ast_tx_protect++;
  	}
  
  	/*
  	 * If 11n protection is enabled and it's a HT frame,
  	 * enable RTS.
  	 *
  	 * XXX ic_htprotmode or ic_curhtprotmode?
  	 * XXX should it_htprotmode only matter if ic_curhtprotmode 
  	 * XXX indicates it's not a HT pure environment?
  	 */
  	if ((ic->ic_htprotmode == IEEE80211_PROT_RTSCTS) &&
  	    rt->info[rix].phy == IEEE80211_T_HT &&
  	    (flags & HAL_TXDESC_NOACK) == 0) {
  		flags |= HAL_TXDESC_RTSENA;
  		sc->sc_stats.ast_tx_htprotect++;
  	}
  	bf->bf_state.bfs_txflags = flags;
  }
  
  /*
   * Update the frame duration given the currently selected rate.
   *
   * This also updates the frame duration value, so it will require
   * a DMA flush.
   */
  static void
  ath_tx_calc_duration(struct ath_softc *sc, struct ath_buf *bf)
  {
  	struct ieee80211_frame *wh;
  	uint8_t rix;
  	uint16_t flags;
  	int shortPreamble;
  	struct ath_hal *ah = sc->sc_ah;
  	const HAL_RATE_TABLE *rt = sc->sc_currates;
  	int isfrag = bf->bf_m->m_flags & M_FRAG;
  
  	flags = bf->bf_state.bfs_txflags;
  	rix = bf->bf_state.bfs_rc[0].rix;
  	shortPreamble = bf->bf_state.bfs_shpream;
  	wh = mtod(bf->bf_m, struct ieee80211_frame *);
  
  	/*
  	 * Calculate duration.  This logically belongs in the 802.11
  	 * layer but it lacks sufficient information to calculate it.
  	 */
  	if ((flags & HAL_TXDESC_NOACK) == 0 &&
  	    (wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) != IEEE80211_FC0_TYPE_CTL) {
  		u_int16_t dur;
  		if (shortPreamble)
  			dur = rt->info[rix].spAckDuration;
  		else
  			dur = rt->info[rix].lpAckDuration;
  		if (wh->i_fc[1] & IEEE80211_FC1_MORE_FRAG) {
  			dur += dur;		/* additional SIFS+ACK */
  			/*
  			 * Include the size of next fragment so NAV is
  			 * updated properly.  The last fragment uses only
  			 * the ACK duration
  			 *
  			 * XXX TODO: ensure that the rate lookup for each
  			 * fragment is the same as the rate used by the
  			 * first fragment!
  			 */
  			dur += ath_hal_computetxtime(ah,
  			    rt,
  			    bf->bf_nextfraglen,
  			    rix, shortPreamble);
  		}
  		if (isfrag) {
  			/*
  			 * Force hardware to use computed duration for next
  			 * fragment by disabling multi-rate retry which updates
  			 * duration based on the multi-rate duration table.
  			 */
  			bf->bf_state.bfs_ismrr = 0;
  			bf->bf_state.bfs_try0 = ATH_TXMGTTRY;
  			/* XXX update bfs_rc[0].try? */
  		}
  
  		/* Update the duration field itself */
  		*(u_int16_t *)wh->i_dur = htole16(dur);
  	}
  }
  
  static uint8_t
  ath_tx_get_rtscts_rate(struct ath_hal *ah, const HAL_RATE_TABLE *rt,
      int cix, int shortPreamble)
  {
  	uint8_t ctsrate;
  
  	/*
  	 * CTS transmit rate is derived from the transmit rate
  	 * by looking in the h/w rate table.  We must also factor
  	 * in whether or not a short preamble is to be used.
  	 */
  	/* NB: cix is set above where RTS/CTS is enabled */
  	KASSERT(cix != 0xff, ("cix not setup"));
  	ctsrate = rt->info[cix].rateCode;
  
  	/* XXX this should only matter for legacy rates */
  	if (shortPreamble)
  		ctsrate |= rt->info[cix].shortPreamble;
  
  	return (ctsrate);
  }
  
  /*
   * Calculate the RTS/CTS duration for legacy frames.
   */
  static int
  ath_tx_calc_ctsduration(struct ath_hal *ah, int rix, int cix,
      int shortPreamble, int pktlen, const HAL_RATE_TABLE *rt,
      int flags)
  {
  	int ctsduration = 0;
  
  	/* This mustn't be called for HT modes */
  	if (rt->info[cix].phy == IEEE80211_T_HT) {
  		printf("%s: HT rate where it shouldn't be (0x%x)\n",
  		    __func__, rt->info[cix].rateCode);
  		return (-1);
  	}
  
  	/*
  	 * Compute the transmit duration based on the frame
  	 * size and the size of an ACK frame.  We call into the
  	 * HAL to do the computation since it depends on the
  	 * characteristics of the actual PHY being used.
  	 *
  	 * NB: CTS is assumed the same size as an ACK so we can
  	 *     use the precalculated ACK durations.
  	 */
  	if (shortPreamble) {
  		if (flags & HAL_TXDESC_RTSENA)		/* SIFS + CTS */
  			ctsduration += rt->info[cix].spAckDuration;
  		ctsduration += ath_hal_computetxtime(ah,
  			rt, pktlen, rix, AH_TRUE);
  		if ((flags & HAL_TXDESC_NOACK) == 0)	/* SIFS + ACK */
  			ctsduration += rt->info[rix].spAckDuration;
  	} else {
  		if (flags & HAL_TXDESC_RTSENA)		/* SIFS + CTS */
  			ctsduration += rt->info[cix].lpAckDuration;
  		ctsduration += ath_hal_computetxtime(ah,
  			rt, pktlen, rix, AH_FALSE);
  		if ((flags & HAL_TXDESC_NOACK) == 0)	/* SIFS + ACK */
  			ctsduration += rt->info[rix].lpAckDuration;
  	}
  
  	return (ctsduration);
  }
  
  /*
   * Update the given ath_buf with updated rts/cts setup and duration
   * values.
   *
   * To support rate lookups for each software retry, the rts/cts rate
   * and cts duration must be re-calculated.
   *
   * This function assumes the RTS/CTS flags have been set as needed;
   * mrr has been disabled; and the rate control lookup has been done.
   *
   * XXX TODO: MRR need only be disabled for the pre-11n NICs.
   * XXX The 11n NICs support per-rate RTS/CTS configuration.
   */
  static void
  ath_tx_set_rtscts(struct ath_softc *sc, struct ath_buf *bf)
  {
  	uint16_t ctsduration = 0;
  	uint8_t ctsrate = 0;
  	uint8_t rix = bf->bf_state.bfs_rc[0].rix;
  	uint8_t cix = 0;
  	const HAL_RATE_TABLE *rt = sc->sc_currates;
  
  	/*
  	 * No RTS/CTS enabled? Don't bother.
  	 */
  	if ((bf->bf_state.bfs_txflags &
  	    (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA)) == 0) {
  		/* XXX is this really needed? */
  		bf->bf_state.bfs_ctsrate = 0;
  		bf->bf_state.bfs_ctsduration = 0;
  		return;
  	}
  
  	/*
  	 * If protection is enabled, use the protection rix control
  	 * rate. Otherwise use the rate0 control rate.
  	 */
  	if (bf->bf_state.bfs_doprot)
  		rix = sc->sc_protrix;
  	else
  		rix = bf->bf_state.bfs_rc[0].rix;
  
  	/*
  	 * If the raw path has hard-coded ctsrate0 to something,
  	 * use it.
  	 */
  	if (bf->bf_state.bfs_ctsrate0 != 0)
  		cix = ath_tx_findrix(sc, bf->bf_state.bfs_ctsrate0);
  	else
  		/* Control rate from above */
  		cix = rt->info[rix].controlRate;
  
  	/* Calculate the rtscts rate for the given cix */
  	ctsrate = ath_tx_get_rtscts_rate(sc->sc_ah, rt, cix,
  	    bf->bf_state.bfs_shpream);
  
  	/* The 11n chipsets do ctsduration calculations for you */
  	if (! ath_tx_is_11n(sc))
  		ctsduration = ath_tx_calc_ctsduration(sc->sc_ah, rix, cix,
  		    bf->bf_state.bfs_shpream, bf->bf_state.bfs_pktlen,
  		    rt, bf->bf_state.bfs_txflags);
  
  	/* Squirrel away in ath_buf */
  	bf->bf_state.bfs_ctsrate = ctsrate;
  	bf->bf_state.bfs_ctsduration = ctsduration;
  	
  	/*
  	 * Must disable multi-rate retry when using RTS/CTS.
  	 */
  	if (!sc->sc_mrrprot) {
  		bf->bf_state.bfs_ismrr = 0;
  		bf->bf_state.bfs_try0 =
  		    bf->bf_state.bfs_rc[0].tries = ATH_TXMGTTRY; /* XXX ew */
  	}
  }
  
  /*
   * Setup the descriptor chain for a normal or fast-frame
   * frame.
   *
   * XXX TODO: extend to include the destination hardware QCU ID.
   * Make sure that is correct.  Make sure that when being added
   * to the mcastq, the CABQ QCUID is set or things will get a bit
   * odd.
   */
  static void
  ath_tx_setds(struct ath_softc *sc, struct ath_buf *bf)
  {
  	struct ath_desc *ds = bf->bf_desc;
  	struct ath_hal *ah = sc->sc_ah;
  
  	if (bf->bf_state.bfs_txrate0 == 0)
  		DPRINTF(sc, ATH_DEBUG_XMIT, 
  		    "%s: bf=%p, txrate0=%d\n", __func__, bf, 0);
  
  	ath_hal_setuptxdesc(ah, ds
  		, bf->bf_state.bfs_pktlen	/* packet length */
  		, bf->bf_state.bfs_hdrlen	/* header length */
  		, bf->bf_state.bfs_atype	/* Atheros packet type */
  		, bf->bf_state.bfs_txpower	/* txpower */
  		, bf->bf_state.bfs_txrate0
  		, bf->bf_state.bfs_try0		/* series 0 rate/tries */
  		, bf->bf_state.bfs_keyix	/* key cache index */
  		, bf->bf_state.bfs_txantenna	/* antenna mode */
  		, bf->bf_state.bfs_txflags	/* flags */
  		, bf->bf_state.bfs_ctsrate	/* rts/cts rate */
  		, bf->bf_state.bfs_ctsduration	/* rts/cts duration */
  	);
  
  	/*
  	 * This will be overriden when the descriptor chain is written.
  	 */
  	bf->bf_lastds = ds;
  	bf->bf_last = bf;
  
  	/* Set rate control and descriptor chain for this frame */
  	ath_tx_set_ratectrl(sc, bf->bf_node, bf);
  	ath_tx_chaindesclist(sc, ds, bf, 0, 0, 0);
  }
  
  /*
   * Do a rate lookup.
   *
   * This performs a rate lookup for the given ath_buf only if it's required.
   * Non-data frames and raw frames don't require it.
   *
   * This populates the primary and MRR entries; MRR values are
   * then disabled later on if something requires it (eg RTS/CTS on
   * pre-11n chipsets.
   *
   * This needs to be done before the RTS/CTS fields are calculated
   * as they may depend upon the rate chosen.
   */
  static void
  ath_tx_do_ratelookup(struct ath_softc *sc, struct ath_buf *bf)
  {
  	uint8_t rate, rix;
  	int try0;
  
  	if (! bf->bf_state.bfs_doratelookup)
  		return;
  
  	/* Get rid of any previous state */
  	bzero(bf->bf_state.bfs_rc, sizeof(bf->bf_state.bfs_rc));
  
  	ATH_NODE_LOCK(ATH_NODE(bf->bf_node));
  	ath_rate_findrate(sc, ATH_NODE(bf->bf_node), bf->bf_state.bfs_shpream,
  	    bf->bf_state.bfs_pktlen, &rix, &try0, &rate);
  
  	/* In case MRR is disabled, make sure rc[0] is setup correctly */
  	bf->bf_state.bfs_rc[0].rix = rix;
  	bf->bf_state.bfs_rc[0].ratecode = rate;
  	bf->bf_state.bfs_rc[0].tries = try0;
  
  	if (bf->bf_state.bfs_ismrr && try0 != ATH_TXMAXTRY)
  		ath_rate_getxtxrates(sc, ATH_NODE(bf->bf_node), rix,
  		    bf->bf_state.bfs_rc);
  	ATH_NODE_UNLOCK(ATH_NODE(bf->bf_node));
  
  	sc->sc_txrix = rix;	/* for LED blinking */
  	sc->sc_lastdatarix = rix;	/* for fast frames */
  	bf->bf_state.bfs_try0 = try0;
  	bf->bf_state.bfs_txrate0 = rate;
  }
  
  /*
   * Update the CLRDMASK bit in the ath_buf if it needs to be set.
   */
  static void
  ath_tx_update_clrdmask(struct ath_softc *sc, struct ath_tid *tid,
      struct ath_buf *bf)
  {
  	struct ath_node *an = ATH_NODE(bf->bf_node);
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	if (an->clrdmask == 1) {
  		bf->bf_state.bfs_txflags |= HAL_TXDESC_CLRDMASK;
  		an->clrdmask = 0;
  	}
  }
  
  /*
   * Return whether this frame should be software queued or
   * direct dispatched.
   *
   * When doing powersave, BAR frames should be queued but other management
   * frames should be directly sent.
   *
   * When not doing powersave, stick BAR frames into the hardware queue
   * so it goes out even though the queue is paused.
   *
   * For now, management frames are also software queued by default.
   */
  static int
  ath_tx_should_swq_frame(struct ath_softc *sc, struct ath_node *an,
      struct mbuf *m0, int *queue_to_head)
  {
  	struct ieee80211_node *ni = &an->an_node;
  	struct ieee80211_frame *wh;
  	uint8_t type, subtype;
  
  	wh = mtod(m0, struct ieee80211_frame *);
  	type = wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK;
  	subtype = wh->i_fc[0] & IEEE80211_FC0_SUBTYPE_MASK;
  
  	(*queue_to_head) = 0;
  
  	/* If it's not in powersave - direct-dispatch BAR */
  	if ((ATH_NODE(ni)->an_is_powersave == 0)
  	    && type == IEEE80211_FC0_TYPE_CTL &&
  	    subtype == IEEE80211_FC0_SUBTYPE_BAR) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX,
  		    "%s: BAR: TX'ing direct\n", __func__);
  		return (0);
  	} else if ((ATH_NODE(ni)->an_is_powersave == 1)
  	    && type == IEEE80211_FC0_TYPE_CTL &&
  	    subtype == IEEE80211_FC0_SUBTYPE_BAR) {
  		/* BAR TX whilst asleep; queue */
  		DPRINTF(sc, ATH_DEBUG_SW_TX,
  		    "%s: swq: TX'ing\n", __func__);
  		(*queue_to_head) = 1;
  		return (1);
  	} else if ((ATH_NODE(ni)->an_is_powersave == 1)
  	    && (type == IEEE80211_FC0_TYPE_MGT ||
  	        type == IEEE80211_FC0_TYPE_CTL)) {
  		/*
  		 * Other control/mgmt frame; bypass software queuing
  		 * for now!
  		 */
  		DPRINTF(sc, ATH_DEBUG_XMIT, 
  		    "%s: %6D: Node is asleep; sending mgmt "
  		    "(type=%d, subtype=%d)\n",
  		    __func__, ni->ni_macaddr, ":", type, subtype);
  		return (0);
  	} else {
  		return (1);
  	}
  }
  
  
  /*
   * Transmit the given frame to the hardware.
   *
   * The frame must already be setup; rate control must already have
   * been done.
   *
   * XXX since the TXQ lock is being held here (and I dislike holding
   * it for this long when not doing software aggregation), later on
   * break this function into "setup_normal" and "xmit_normal". The
   * lock only needs to be held for the ath_tx_handoff call.
   *
   * XXX we don't update the leak count here - if we're doing
   * direct frame dispatch, we need to be able to do it without
   * decrementing the leak count (eg multicast queue frames.)
   */
  static void
  ath_tx_xmit_normal(struct ath_softc *sc, struct ath_txq *txq,
      struct ath_buf *bf)
  {
  	struct ath_node *an = ATH_NODE(bf->bf_node);
  	struct ath_tid *tid = &an->an_tid[bf->bf_state.bfs_tid];
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/*
  	 * For now, just enable CLRDMASK. ath_tx_xmit_normal() does
  	 * set a completion handler however it doesn't (yet) properly
  	 * handle the strict ordering requirements needed for normal,
  	 * non-aggregate session frames.
  	 *
  	 * Once this is implemented, only set CLRDMASK like this for
  	 * frames that must go out - eg management/raw frames.
  	 */
  	bf->bf_state.bfs_txflags |= HAL_TXDESC_CLRDMASK;
  
  	/* Setup the descriptor before handoff */
  	ath_tx_do_ratelookup(sc, bf);
  	ath_tx_calc_duration(sc, bf);
  	ath_tx_calc_protection(sc, bf);
  	ath_tx_set_rtscts(sc, bf);
  	ath_tx_rate_fill_rcflags(sc, bf);
  	ath_tx_setds(sc, bf);
  
  	/* Track per-TID hardware queue depth correctly */
  	tid->hwq_depth++;
  
  	/* Assign the completion handler */
  	bf->bf_comp = ath_tx_normal_comp;
  
  	/* Hand off to hardware */
  	ath_tx_handoff(sc, txq, bf);
  }
  
  /*
   * Do the basic frame setup stuff that's required before the frame
   * is added to a software queue.
   *
   * All frames get mostly the same treatment and it's done once.
   * Retransmits fiddle with things like the rate control setup,
   * setting the retransmit bit in the packet; doing relevant DMA/bus
   * syncing and relinking it (back) into the hardware TX queue.
   *
   * Note that this may cause the mbuf to be reallocated, so
   * m0 may not be valid.
   */
  static int
  ath_tx_normal_setup(struct ath_softc *sc, struct ieee80211_node *ni,
      struct ath_buf *bf, struct mbuf *m0, struct ath_txq *txq)
  {
  	struct ieee80211vap *vap = ni->ni_vap;
  	struct ath_hal *ah = sc->sc_ah;
  	struct ieee80211com *ic = &sc->sc_ic;
  	const struct chanAccParams *cap = &ic->ic_wme.wme_chanParams;
  	int error, iswep, ismcast, isfrag, ismrr;
  	int keyix, hdrlen, pktlen, try0 = 0;
  	u_int8_t rix = 0, txrate = 0;
  	struct ath_desc *ds;
  	struct ieee80211_frame *wh;
  	u_int subtype, flags;
  	HAL_PKT_TYPE atype;
  	const HAL_RATE_TABLE *rt;
  	HAL_BOOL shortPreamble;
  	struct ath_node *an;
  	u_int pri;
  
  	/*
  	 * To ensure that both sequence numbers and the CCMP PN handling
  	 * is "correct", make sure that the relevant TID queue is locked.
  	 * Otherwise the CCMP PN and seqno may appear out of order, causing
  	 * re-ordered frames to have out of order CCMP PN's, resulting
  	 * in many, many frame drops.
  	 */
  	ATH_TX_LOCK_ASSERT(sc);
  
  	wh = mtod(m0, struct ieee80211_frame *);
  	iswep = wh->i_fc[1] & IEEE80211_FC1_PROTECTED;
  	ismcast = IEEE80211_IS_MULTICAST(wh->i_addr1);
  	isfrag = m0->m_flags & M_FRAG;
  	hdrlen = ieee80211_anyhdrsize(wh);
  	/*
  	 * Packet length must not include any
  	 * pad bytes; deduct them here.
  	 */
  	pktlen = m0->m_pkthdr.len - (hdrlen & 3);
  
  	/* Handle encryption twiddling if needed */
  	if (! ath_tx_tag_crypto(sc, ni, m0, iswep, isfrag, &hdrlen,
  	    &pktlen, &keyix)) {
  		ieee80211_free_mbuf(m0);
  		return EIO;
  	}
  
  	/* packet header may have moved, reset our local pointer */
  	wh = mtod(m0, struct ieee80211_frame *);
  
  	pktlen += IEEE80211_CRC_LEN;
  
  	/*
  	 * Load the DMA map so any coalescing is done.  This
  	 * also calculates the number of descriptors we need.
  	 */
  	error = ath_tx_dmasetup(sc, bf, m0);
  	if (error != 0)
  		return error;
  	KASSERT((ni != NULL), ("%s: ni=NULL!", __func__));
  	bf->bf_node = ni;			/* NB: held reference */
  	m0 = bf->bf_m;				/* NB: may have changed */
  	wh = mtod(m0, struct ieee80211_frame *);
  
  	/* setup descriptors */
  	ds = bf->bf_desc;
  	rt = sc->sc_currates;
  	KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
  
  	/*
  	 * NB: the 802.11 layer marks whether or not we should
  	 * use short preamble based on the current mode and
  	 * negotiated parameters.
  	 */
  	if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
  	    (ni->ni_capinfo & IEEE80211_CAPINFO_SHORT_PREAMBLE)) {
  		shortPreamble = AH_TRUE;
  		sc->sc_stats.ast_tx_shortpre++;
  	} else {
  		shortPreamble = AH_FALSE;
  	}
  
  	an = ATH_NODE(ni);
  	//flags = HAL_TXDESC_CLRDMASK;		/* XXX needed for crypto errs */
  	flags = 0;
  	ismrr = 0;				/* default no multi-rate retry*/
  	pri = M_WME_GETAC(m0);			/* honor classification */
  	/* XXX use txparams instead of fixed values */
  	/*
  	 * Calculate Atheros packet type from IEEE80211 packet header,
  	 * setup for rate calculations, and select h/w transmit queue.
  	 */
  	switch (wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) {
  	case IEEE80211_FC0_TYPE_MGT:
  		subtype = wh->i_fc[0] & IEEE80211_FC0_SUBTYPE_MASK;
  		if (subtype == IEEE80211_FC0_SUBTYPE_BEACON)
  			atype = HAL_PKT_TYPE_BEACON;
  		else if (subtype == IEEE80211_FC0_SUBTYPE_PROBE_RESP)
  			atype = HAL_PKT_TYPE_PROBE_RESP;
  		else if (subtype == IEEE80211_FC0_SUBTYPE_ATIM)
  			atype = HAL_PKT_TYPE_ATIM;
  		else
  			atype = HAL_PKT_TYPE_NORMAL;	/* XXX */
  		rix = an->an_mgmtrix;
  		txrate = rt->info[rix].rateCode;
  		if (shortPreamble)
  			txrate |= rt->info[rix].shortPreamble;
  		try0 = ATH_TXMGTTRY;
  		flags |= HAL_TXDESC_INTREQ;	/* force interrupt */
  		break;
  	case IEEE80211_FC0_TYPE_CTL:
  		atype = HAL_PKT_TYPE_PSPOLL;	/* stop setting of duration */
  		rix = an->an_mgmtrix;
  		txrate = rt->info[rix].rateCode;
  		if (shortPreamble)
  			txrate |= rt->info[rix].shortPreamble;
  		try0 = ATH_TXMGTTRY;
  		flags |= HAL_TXDESC_INTREQ;	/* force interrupt */
  		break;
  	case IEEE80211_FC0_TYPE_DATA:
  		atype = HAL_PKT_TYPE_NORMAL;		/* default */
  		/*
  		 * Data frames: multicast frames go out at a fixed rate,
  		 * EAPOL frames use the mgmt frame rate; otherwise consult
  		 * the rate control module for the rate to use.
  		 */
  		if (ismcast) {
  			rix = an->an_mcastrix;
  			txrate = rt->info[rix].rateCode;
  			if (shortPreamble)
  				txrate |= rt->info[rix].shortPreamble;
  			try0 = 1;
  		} else if (m0->m_flags & M_EAPOL) {
  			/* XXX? maybe always use long preamble? */
  			rix = an->an_mgmtrix;
  			txrate = rt->info[rix].rateCode;
  			if (shortPreamble)
  				txrate |= rt->info[rix].shortPreamble;
  			try0 = ATH_TXMAXTRY;	/* XXX?too many? */
  		} else {
  			/*
  			 * Do rate lookup on each TX, rather than using
  			 * the hard-coded TX information decided here.
  			 */
  			ismrr = 1;
  			bf->bf_state.bfs_doratelookup = 1;
  		}
  		if (cap->cap_wmeParams[pri].wmep_noackPolicy)
  			flags |= HAL_TXDESC_NOACK;
  		break;
  	default:
  		device_printf(sc->sc_dev, "bogus frame type 0x%x (%s)\n",
  		    wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK, __func__);
  		/* XXX statistic */
  		/* XXX free tx dmamap */
  		ieee80211_free_mbuf(m0);
  		return EIO;
  	}
  
  	/*
  	 * There are two known scenarios where the frame AC doesn't match
  	 * what the destination TXQ is.
  	 *
  	 * + non-QoS frames (eg management?) that the net80211 stack has
  	 *   assigned a higher AC to, but since it's a non-QoS TID, it's
  	 *   being thrown into TID 16.  TID 16 gets the AC_BE queue.
  	 *   It's quite possible that management frames should just be
  	 *   direct dispatched to hardware rather than go via the software
  	 *   queue; that should be investigated in the future.  There are
  	 *   some specific scenarios where this doesn't make sense, mostly
  	 *   surrounding ADDBA request/response - hence why that is special
  	 *   cased.
  	 *
  	 * + Multicast frames going into the VAP mcast queue.  That shows up
  	 *   as "TXQ 11".
  	 *
  	 * This driver should eventually support separate TID and TXQ locking,
  	 * allowing for arbitrary AC frames to appear on arbitrary software
  	 * queues, being queued to the "correct" hardware queue when needed.
  	 */
  #if 0
  	if (txq != sc->sc_ac2q[pri]) {
  		DPRINTF(sc, ATH_DEBUG_XMIT, 
  		    "%s: txq=%p (%d), pri=%d, pri txq=%p (%d)\n",
  		    __func__,
  		    txq,
  		    txq->axq_qnum,
  		    pri,
  		    sc->sc_ac2q[pri],
  		    sc->sc_ac2q[pri]->axq_qnum);
  	}
  #endif
  
  	/*
  	 * Calculate miscellaneous flags.
  	 */
  	if (ismcast) {
  		flags |= HAL_TXDESC_NOACK;	/* no ack on broad/multicast */
  	} else if (pktlen > vap->iv_rtsthreshold &&
  	    (ni->ni_ath_flags & IEEE80211_NODE_FF) == 0) {
  		flags |= HAL_TXDESC_RTSENA;	/* RTS based on frame length */
  		sc->sc_stats.ast_tx_rts++;
  	}
  	if (flags & HAL_TXDESC_NOACK)		/* NB: avoid double counting */
  		sc->sc_stats.ast_tx_noack++;
  #ifdef IEEE80211_SUPPORT_TDMA
  	if (sc->sc_tdma && (flags & HAL_TXDESC_NOACK) == 0) {
  		DPRINTF(sc, ATH_DEBUG_TDMA,
  		    "%s: discard frame, ACK required w/ TDMA\n", __func__);
  		sc->sc_stats.ast_tdma_ack++;
  		/* XXX free tx dmamap */
  		ieee80211_free_mbuf(m0);
  		return EIO;
  	}
  #endif
  
  	/*
  	 * Determine if a tx interrupt should be generated for
  	 * this descriptor.  We take a tx interrupt to reap
  	 * descriptors when the h/w hits an EOL condition or
  	 * when the descriptor is specifically marked to generate
  	 * an interrupt.  We periodically mark descriptors in this
  	 * way to insure timely replenishing of the supply needed
  	 * for sending frames.  Defering interrupts reduces system
  	 * load and potentially allows more concurrent work to be
  	 * done but if done to aggressively can cause senders to
  	 * backup.
  	 *
  	 * NB: use >= to deal with sc_txintrperiod changing
  	 *     dynamically through sysctl.
  	 */
  	if (flags & HAL_TXDESC_INTREQ) {
  		txq->axq_intrcnt = 0;
  	} else if (++txq->axq_intrcnt >= sc->sc_txintrperiod) {
  		flags |= HAL_TXDESC_INTREQ;
  		txq->axq_intrcnt = 0;
  	}
  
  	/* This point forward is actual TX bits */
  
  	/*
  	 * At this point we are committed to sending the frame
  	 * and we don't need to look at m_nextpkt; clear it in
  	 * case this frame is part of frag chain.
  	 */
  	m0->m_nextpkt = NULL;
  
  	if (IFF_DUMPPKTS(sc, ATH_DEBUG_XMIT))
  		ieee80211_dump_pkt(ic, mtod(m0, const uint8_t *), m0->m_len,
  		    sc->sc_hwmap[rix].ieeerate, -1);
  
  	if (ieee80211_radiotap_active_vap(vap)) {
  		u_int64_t tsf = ath_hal_gettsf64(ah);
  
  		sc->sc_tx_th.wt_tsf = htole64(tsf);
  		sc->sc_tx_th.wt_flags = sc->sc_hwmap[rix].txflags;
  		if (iswep)
  			sc->sc_tx_th.wt_flags |= IEEE80211_RADIOTAP_F_WEP;
  		if (isfrag)
  			sc->sc_tx_th.wt_flags |= IEEE80211_RADIOTAP_F_FRAG;
  		sc->sc_tx_th.wt_rate = sc->sc_hwmap[rix].ieeerate;
  		sc->sc_tx_th.wt_txpower = ieee80211_get_node_txpower(ni);
  		sc->sc_tx_th.wt_antenna = sc->sc_txantenna;
  
  		ieee80211_radiotap_tx(vap, m0);
  	}
  
  	/* Blank the legacy rate array */
  	bzero(&bf->bf_state.bfs_rc, sizeof(bf->bf_state.bfs_rc));
  
  	/*
  	 * ath_buf_set_rate needs at least one rate/try to setup
  	 * the rate scenario.
  	 */
  	bf->bf_state.bfs_rc[0].rix = rix;
  	bf->bf_state.bfs_rc[0].tries = try0;
  	bf->bf_state.bfs_rc[0].ratecode = txrate;
  
  	/* Store the decided rate index values away */
  	bf->bf_state.bfs_pktlen = pktlen;
  	bf->bf_state.bfs_hdrlen = hdrlen;
  	bf->bf_state.bfs_atype = atype;
  	bf->bf_state.bfs_txpower = ieee80211_get_node_txpower(ni);
  	bf->bf_state.bfs_txrate0 = txrate;
  	bf->bf_state.bfs_try0 = try0;
  	bf->bf_state.bfs_keyix = keyix;
  	bf->bf_state.bfs_txantenna = sc->sc_txantenna;
  	bf->bf_state.bfs_txflags = flags;
  	bf->bf_state.bfs_shpream = shortPreamble;
  
  	/* XXX this should be done in ath_tx_setrate() */
  	bf->bf_state.bfs_ctsrate0 = 0;	/* ie, no hard-coded ctsrate */
  	bf->bf_state.bfs_ctsrate = 0;	/* calculated later */
  	bf->bf_state.bfs_ctsduration = 0;
  	bf->bf_state.bfs_ismrr = ismrr;
  
  	return 0;
  }
  
  /*
   * Queue a frame to the hardware or software queue.
   *
   * This can be called by the net80211 code.
   *
   * XXX what about locking? Or, push the seqno assign into the
   * XXX aggregate scheduler so its serialised?
   *
   * XXX When sending management frames via ath_raw_xmit(),
   *     should CLRDMASK be set unconditionally?
   */
  int
  ath_tx_start(struct ath_softc *sc, struct ieee80211_node *ni,
      struct ath_buf *bf, struct mbuf *m0)
  {
  	struct ieee80211vap *vap = ni->ni_vap;
  	struct ath_vap *avp = ATH_VAP(vap);
  	int r = 0;
  	u_int pri;
  	int tid;
  	struct ath_txq *txq;
  	int ismcast;
  	const struct ieee80211_frame *wh;
  	int is_ampdu, is_ampdu_tx, is_ampdu_pending;
  	ieee80211_seq seqno;
  	uint8_t type, subtype;
  	int queue_to_head;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/*
  	 * Determine the target hardware queue.
  	 *
  	 * For multicast frames, the txq gets overridden appropriately
  	 * depending upon the state of PS.
  	 *
  	 * For any other frame, we do a TID/QoS lookup inside the frame
  	 * to see what the TID should be. If it's a non-QoS frame, the
  	 * AC and TID are overridden. The TID/TXQ code assumes the
  	 * TID is on a predictable hardware TXQ, so we don't support
  	 * having a node TID queued to multiple hardware TXQs.
  	 * This may change in the future but would require some locking
  	 * fudgery.
  	 */
  	pri = ath_tx_getac(sc, m0);
  	tid = ath_tx_gettid(sc, m0);
  
  	txq = sc->sc_ac2q[pri];
  	wh = mtod(m0, struct ieee80211_frame *);
  	ismcast = IEEE80211_IS_MULTICAST(wh->i_addr1);
  	type = wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK;
  	subtype = wh->i_fc[0] & IEEE80211_FC0_SUBTYPE_MASK;
  
  	/*
  	 * Enforce how deep the multicast queue can grow.
  	 *
  	 * XXX duplicated in ath_raw_xmit().
  	 */
  	if (IEEE80211_IS_MULTICAST(wh->i_addr1)) {
  		if (sc->sc_cabq->axq_depth + sc->sc_cabq->fifo.axq_depth
  		    > sc->sc_txq_mcastq_maxdepth) {
  			sc->sc_stats.ast_tx_mcastq_overflow++;
  			m_freem(m0);
  			return (ENOBUFS);
  		}
  	}
  
  	/*
  	 * Enforce how deep the unicast queue can grow.
  	 *
  	 * If the node is in power save then we don't want
  	 * the software queue to grow too deep, or a node may
  	 * end up consuming all of the ath_buf entries.
  	 *
  	 * For now, only do this for DATA frames.
  	 *
  	 * We will want to cap how many management/control
  	 * frames get punted to the software queue so it doesn't
  	 * fill up.  But the correct solution isn't yet obvious.
  	 * In any case, this check should at least let frames pass
  	 * that we are direct-dispatching.
  	 *
  	 * XXX TODO: duplicate this to the raw xmit path!
  	 */
  	if (type == IEEE80211_FC0_TYPE_DATA &&
  	    ATH_NODE(ni)->an_is_powersave &&
  	    ATH_NODE(ni)->an_swq_depth >
  	     sc->sc_txq_node_psq_maxdepth) {
  		sc->sc_stats.ast_tx_node_psq_overflow++;
  		m_freem(m0);
  		return (ENOBUFS);
  	}
  
  	/* A-MPDU TX */
  	is_ampdu_tx = ath_tx_ampdu_running(sc, ATH_NODE(ni), tid);
  	is_ampdu_pending = ath_tx_ampdu_pending(sc, ATH_NODE(ni), tid);
  	is_ampdu = is_ampdu_tx | is_ampdu_pending;
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: tid=%d, ac=%d, is_ampdu=%d\n",
  	    __func__, tid, pri, is_ampdu);
  
  	/* Set local packet state, used to queue packets to hardware */
  	bf->bf_state.bfs_tid = tid;
  	bf->bf_state.bfs_tx_queue = txq->axq_qnum;
  	bf->bf_state.bfs_pri = pri;
  
  #if 1
  	/*
  	 * When servicing one or more stations in power-save mode
  	 * (or) if there is some mcast data waiting on the mcast
  	 * queue (to prevent out of order delivery) multicast frames
  	 * must be bufferd until after the beacon.
  	 *
  	 * TODO: we should lock the mcastq before we check the length.
  	 */
  	if (sc->sc_cabq_enable && ismcast && (vap->iv_ps_sta || avp->av_mcastq.axq_depth)) {
  		txq = &avp->av_mcastq;
  		/*
  		 * Mark the frame as eventually belonging on the CAB
  		 * queue, so the descriptor setup functions will
  		 * correctly initialise the descriptor 'qcuId' field.
  		 */
  		bf->bf_state.bfs_tx_queue = sc->sc_cabq->axq_qnum;
  	}
  #endif
  
  	/* Do the generic frame setup */
  	/* XXX should just bzero the bf_state? */
  	bf->bf_state.bfs_dobaw = 0;
  
  	/* A-MPDU TX? Manually set sequence number */
  	/*
  	 * Don't do it whilst pending; the net80211 layer still
  	 * assigns them.
  	 */
  	if (is_ampdu_tx) {
  		/*
  		 * Always call; this function will
  		 * handle making sure that null data frames
  		 * don't get a sequence number from the current
  		 * TID and thus mess with the BAW.
  		 */
  		seqno = ath_tx_tid_seqno_assign(sc, ni, bf, m0);
  
  		/*
  		 * Don't add QoS NULL frames to the BAW.
  		 */
  		if (IEEE80211_QOS_HAS_SEQ(wh) &&
  		    subtype != IEEE80211_FC0_SUBTYPE_QOS_NULL) {
  			bf->bf_state.bfs_dobaw = 1;
  		}
  	}
  
  	/*
  	 * If needed, the sequence number has been assigned.
  	 * Squirrel it away somewhere easy to get to.
  	 */
  	bf->bf_state.bfs_seqno = M_SEQNO_GET(m0) << IEEE80211_SEQ_SEQ_SHIFT;
  
  	/* Is ampdu pending? fetch the seqno and print it out */
  	if (is_ampdu_pending)
  		DPRINTF(sc, ATH_DEBUG_SW_TX,
  		    "%s: tid %d: ampdu pending, seqno %d\n",
  		    __func__, tid, M_SEQNO_GET(m0));
  
  	/* This also sets up the DMA map */
  	r = ath_tx_normal_setup(sc, ni, bf, m0, txq);
  
  	if (r != 0)
  		goto done;
  
  	/* At this point m0 could have changed! */
  	m0 = bf->bf_m;
  
  #if 1
  	/*
  	 * If it's a multicast frame, do a direct-dispatch to the
  	 * destination hardware queue. Don't bother software
  	 * queuing it.
  	 */
  	/*
  	 * If it's a BAR frame, do a direct dispatch to the
  	 * destination hardware queue. Don't bother software
  	 * queuing it, as the TID will now be paused.
  	 * Sending a BAR frame can occur from the net80211 txa timer
  	 * (ie, retries) or from the ath txtask (completion call.)
  	 * It queues directly to hardware because the TID is paused
  	 * at this point (and won't be unpaused until the BAR has
  	 * either been TXed successfully or max retries has been
  	 * reached.)
  	 */
  	/*
  	 * Until things are better debugged - if this node is asleep
  	 * and we're sending it a non-BAR frame, direct dispatch it.
  	 * Why? Because we need to figure out what's actually being
  	 * sent - eg, during reassociation/reauthentication after
  	 * the node (last) disappeared whilst asleep, the driver should
  	 * have unpaused/unsleep'ed the node.  So until that is
  	 * sorted out, use this workaround.
  	 */
  	if (txq == &avp->av_mcastq) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX,
  		    "%s: bf=%p: mcastq: TX'ing\n", __func__, bf);
  		bf->bf_state.bfs_txflags |= HAL_TXDESC_CLRDMASK;
  		ath_tx_xmit_normal(sc, txq, bf);
  	} else if (ath_tx_should_swq_frame(sc, ATH_NODE(ni), m0,
  	    &queue_to_head)) {
  		ath_tx_swq(sc, ni, txq, queue_to_head, bf);
  	} else {
  		bf->bf_state.bfs_txflags |= HAL_TXDESC_CLRDMASK;
  		ath_tx_xmit_normal(sc, txq, bf);
  	}
  #else
  	/*
  	 * For now, since there's no software queue,
  	 * direct-dispatch to the hardware.
  	 */
  	bf->bf_state.bfs_txflags |= HAL_TXDESC_CLRDMASK;
  	/*
  	 * Update the current leak count if
  	 * we're leaking frames; and set the
  	 * MORE flag as appropriate.
  	 */
  	ath_tx_leak_count_update(sc, tid, bf);
  	ath_tx_xmit_normal(sc, txq, bf);
  #endif
  done:
  	return 0;
  }
  
  static int
  ath_tx_raw_start(struct ath_softc *sc, struct ieee80211_node *ni,
  	struct ath_buf *bf, struct mbuf *m0,
  	const struct ieee80211_bpf_params *params)
  {
  	struct ieee80211com *ic = &sc->sc_ic;
  	struct ath_hal *ah = sc->sc_ah;
  	struct ieee80211vap *vap = ni->ni_vap;
  	int error, ismcast, ismrr;
  	int keyix, hdrlen, pktlen, try0, txantenna;
  	u_int8_t rix, txrate;
  	struct ieee80211_frame *wh;
  	u_int flags;
  	HAL_PKT_TYPE atype;
  	const HAL_RATE_TABLE *rt;
  	struct ath_desc *ds;
  	u_int pri;
  	int o_tid = -1;
  	int do_override;
  	uint8_t type, subtype;
  	int queue_to_head;
  	struct ath_node *an = ATH_NODE(ni);
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	wh = mtod(m0, struct ieee80211_frame *);
  	ismcast = IEEE80211_IS_MULTICAST(wh->i_addr1);
  	hdrlen = ieee80211_anyhdrsize(wh);
  	/*
  	 * Packet length must not include any
  	 * pad bytes; deduct them here.
  	 */
  	/* XXX honor IEEE80211_BPF_DATAPAD */
  	pktlen = m0->m_pkthdr.len - (hdrlen & 3) + IEEE80211_CRC_LEN;
  
  	type = wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK;
  	subtype = wh->i_fc[0] & IEEE80211_FC0_SUBTYPE_MASK;
  
  	ATH_KTR(sc, ATH_KTR_TX, 2,
  	     "ath_tx_raw_start: ni=%p, bf=%p, raw", ni, bf);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: ismcast=%d\n",
  	    __func__, ismcast);
  
  	pri = params->ibp_pri & 3;
  	/* Override pri if the frame isn't a QoS one */
  	if (! IEEE80211_QOS_HAS_SEQ(wh))
  		pri = ath_tx_getac(sc, m0);
  
  	/* XXX If it's an ADDBA, override the correct queue */
  	do_override = ath_tx_action_frame_override_queue(sc, ni, m0, &o_tid);
  
  	/* Map ADDBA to the correct priority */
  	if (do_override) {
  #if 0
  		DPRINTF(sc, ATH_DEBUG_XMIT, 
  		    "%s: overriding tid %d pri %d -> %d\n",
  		    __func__, o_tid, pri, TID_TO_WME_AC(o_tid));
  #endif
  		pri = TID_TO_WME_AC(o_tid);
  	}
  
  	/* Handle encryption twiddling if needed */
  	if (! ath_tx_tag_crypto(sc, ni,
  	    m0, params->ibp_flags & IEEE80211_BPF_CRYPTO, 0,
  	    &hdrlen, &pktlen, &keyix)) {
  		ieee80211_free_mbuf(m0);
  		return EIO;
  	}
  	/* packet header may have moved, reset our local pointer */
  	wh = mtod(m0, struct ieee80211_frame *);
  
  	/* Do the generic frame setup */
  	/* XXX should just bzero the bf_state? */
  	bf->bf_state.bfs_dobaw = 0;
  
  	error = ath_tx_dmasetup(sc, bf, m0);
  	if (error != 0)
  		return error;
  	m0 = bf->bf_m;				/* NB: may have changed */
  	wh = mtod(m0, struct ieee80211_frame *);
  	KASSERT((ni != NULL), ("%s: ni=NULL!", __func__));
  	bf->bf_node = ni;			/* NB: held reference */
  
  	/* Always enable CLRDMASK for raw frames for now.. */
  	flags = HAL_TXDESC_CLRDMASK;		/* XXX needed for crypto errs */
  	flags |= HAL_TXDESC_INTREQ;		/* force interrupt */
  	if (params->ibp_flags & IEEE80211_BPF_RTS)
  		flags |= HAL_TXDESC_RTSENA;
  	else if (params->ibp_flags & IEEE80211_BPF_CTS) {
  		/* XXX assume 11g/11n protection? */
  		bf->bf_state.bfs_doprot = 1;
  		flags |= HAL_TXDESC_CTSENA;
  	}
  	/* XXX leave ismcast to injector? */
  	if ((params->ibp_flags & IEEE80211_BPF_NOACK) || ismcast)
  		flags |= HAL_TXDESC_NOACK;
  
  	rt = sc->sc_currates;
  	KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
  
  	/* Fetch first rate information */
  	rix = ath_tx_findrix(sc, params->ibp_rate0);
  	try0 = params->ibp_try0;
  
  	/*
  	 * Override EAPOL rate as appropriate.
  	 */
  	if (m0->m_flags & M_EAPOL) {
  		/* XXX? maybe always use long preamble? */
  		rix = an->an_mgmtrix;
  		try0 = ATH_TXMAXTRY;	/* XXX?too many? */
  	}
  
  	txrate = rt->info[rix].rateCode;
  	if (params->ibp_flags & IEEE80211_BPF_SHORTPRE)
  		txrate |= rt->info[rix].shortPreamble;
  	sc->sc_txrix = rix;
  	ismrr = (params->ibp_try1 != 0);
  	txantenna = params->ibp_pri >> 2;
  	if (txantenna == 0)			/* XXX? */
  		txantenna = sc->sc_txantenna;
  
  	/*
  	 * Since ctsrate is fixed, store it away for later
  	 * use when the descriptor fields are being set.
  	 */
  	if (flags & (HAL_TXDESC_RTSENA|HAL_TXDESC_CTSENA))
  		bf->bf_state.bfs_ctsrate0 = params->ibp_ctsrate;
  
  	/*
  	 * NB: we mark all packets as type PSPOLL so the h/w won't
  	 * set the sequence number, duration, etc.
  	 */
  	atype = HAL_PKT_TYPE_PSPOLL;
  
  	if (IFF_DUMPPKTS(sc, ATH_DEBUG_XMIT))
  		ieee80211_dump_pkt(ic, mtod(m0, caddr_t), m0->m_len,
  		    sc->sc_hwmap[rix].ieeerate, -1);
  
  	if (ieee80211_radiotap_active_vap(vap)) {
  		u_int64_t tsf = ath_hal_gettsf64(ah);
  
  		sc->sc_tx_th.wt_tsf = htole64(tsf);
  		sc->sc_tx_th.wt_flags = sc->sc_hwmap[rix].txflags;
  		if (wh->i_fc[1] & IEEE80211_FC1_PROTECTED)
  			sc->sc_tx_th.wt_flags |= IEEE80211_RADIOTAP_F_WEP;
  		if (m0->m_flags & M_FRAG)
  			sc->sc_tx_th.wt_flags |= IEEE80211_RADIOTAP_F_FRAG;
  		sc->sc_tx_th.wt_rate = sc->sc_hwmap[rix].ieeerate;
  		sc->sc_tx_th.wt_txpower = MIN(params->ibp_power,
  		    ieee80211_get_node_txpower(ni));
  		sc->sc_tx_th.wt_antenna = sc->sc_txantenna;
  
  		ieee80211_radiotap_tx(vap, m0);
  	}
  
  	/*
  	 * Formulate first tx descriptor with tx controls.
  	 */
  	ds = bf->bf_desc;
  	/* XXX check return value? */
  
  	/* Store the decided rate index values away */
  	bf->bf_state.bfs_pktlen = pktlen;
  	bf->bf_state.bfs_hdrlen = hdrlen;
  	bf->bf_state.bfs_atype = atype;
  	bf->bf_state.bfs_txpower = MIN(params->ibp_power,
  	    ieee80211_get_node_txpower(ni));
  	bf->bf_state.bfs_txrate0 = txrate;
  	bf->bf_state.bfs_try0 = try0;
  	bf->bf_state.bfs_keyix = keyix;
  	bf->bf_state.bfs_txantenna = txantenna;
  	bf->bf_state.bfs_txflags = flags;
  	bf->bf_state.bfs_shpream =
  	    !! (params->ibp_flags & IEEE80211_BPF_SHORTPRE);
  
  	/* Set local packet state, used to queue packets to hardware */
  	bf->bf_state.bfs_tid = WME_AC_TO_TID(pri);
  	bf->bf_state.bfs_tx_queue = sc->sc_ac2q[pri]->axq_qnum;
  	bf->bf_state.bfs_pri = pri;
  
  	/* XXX this should be done in ath_tx_setrate() */
  	bf->bf_state.bfs_ctsrate = 0;
  	bf->bf_state.bfs_ctsduration = 0;
  	bf->bf_state.bfs_ismrr = ismrr;
  
  	/* Blank the legacy rate array */
  	bzero(&bf->bf_state.bfs_rc, sizeof(bf->bf_state.bfs_rc));
  
  	bf->bf_state.bfs_rc[0].rix = rix;
  	bf->bf_state.bfs_rc[0].tries = try0;
  	bf->bf_state.bfs_rc[0].ratecode = txrate;
  
  	if (ismrr) {
  		int rix;
  
  		rix = ath_tx_findrix(sc, params->ibp_rate1);
  		bf->bf_state.bfs_rc[1].rix = rix;
  		bf->bf_state.bfs_rc[1].tries = params->ibp_try1;
  
  		rix = ath_tx_findrix(sc, params->ibp_rate2);
  		bf->bf_state.bfs_rc[2].rix = rix;
  		bf->bf_state.bfs_rc[2].tries = params->ibp_try2;
  
  		rix = ath_tx_findrix(sc, params->ibp_rate3);
  		bf->bf_state.bfs_rc[3].rix = rix;
  		bf->bf_state.bfs_rc[3].tries = params->ibp_try3;
  	}
  	/*
  	 * All the required rate control decisions have been made;
  	 * fill in the rc flags.
  	 */
  	ath_tx_rate_fill_rcflags(sc, bf);
  
  	/* NB: no buffered multicast in power save support */
  
  	/*
  	 * If we're overiding the ADDBA destination, dump directly
  	 * into the hardware queue, right after any pending
  	 * frames to that node are.
  	 */
  	DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: dooverride=%d\n",
  	    __func__, do_override);
  
  #if 1
  	/*
  	 * Put addba frames in the right place in the right TID/HWQ.
  	 */
  	if (do_override) {
  		bf->bf_state.bfs_txflags |= HAL_TXDESC_CLRDMASK;
  		/*
  		 * XXX if it's addba frames, should we be leaking
  		 * them out via the frame leak method?
  		 * XXX for now let's not risk it; but we may wish
  		 * to investigate this later.
  		 */
  		ath_tx_xmit_normal(sc, sc->sc_ac2q[pri], bf);
  	} else if (ath_tx_should_swq_frame(sc, ATH_NODE(ni), m0,
  	    &queue_to_head)) {
  		/* Queue to software queue */
  		ath_tx_swq(sc, ni, sc->sc_ac2q[pri], queue_to_head, bf);
  	} else {
  		bf->bf_state.bfs_txflags |= HAL_TXDESC_CLRDMASK;
  		ath_tx_xmit_normal(sc, sc->sc_ac2q[pri], bf);
  	}
  #else
  	/* Direct-dispatch to the hardware */
  	bf->bf_state.bfs_txflags |= HAL_TXDESC_CLRDMASK;
  	/*
  	 * Update the current leak count if
  	 * we're leaking frames; and set the
  	 * MORE flag as appropriate.
  	 */
  	ath_tx_leak_count_update(sc, tid, bf);
  	ath_tx_xmit_normal(sc, sc->sc_ac2q[pri], bf);
  #endif
  	return 0;
  }
  
  /*
   * Send a raw frame.
   *
   * This can be called by net80211.
   */
  int
  ath_raw_xmit(struct ieee80211_node *ni, struct mbuf *m,
  	const struct ieee80211_bpf_params *params)
  {
  	struct ieee80211com *ic = ni->ni_ic;
  	struct ath_softc *sc = ic->ic_softc;
  	struct ath_buf *bf;
  	struct ieee80211_frame *wh = mtod(m, struct ieee80211_frame *);
  	int error = 0;
  
  	ATH_PCU_LOCK(sc);
  	if (sc->sc_inreset_cnt > 0) {
  		DPRINTF(sc, ATH_DEBUG_XMIT, 
  		    "%s: sc_inreset_cnt > 0; bailing\n", __func__);
  		error = EIO;
  		ATH_PCU_UNLOCK(sc);
  		goto badbad;
  	}
  	sc->sc_txstart_cnt++;
  	ATH_PCU_UNLOCK(sc);
  
  	/* Wake the hardware up already */
  	ATH_LOCK(sc);
  	ath_power_set_power_state(sc, HAL_PM_AWAKE);
  	ATH_UNLOCK(sc);
  
  	ATH_TX_LOCK(sc);
  
  	if (!sc->sc_running || sc->sc_invalid) {
  		DPRINTF(sc, ATH_DEBUG_XMIT, "%s: discard frame, r/i: %d/%d",
  		    __func__, sc->sc_running, sc->sc_invalid);
  		m_freem(m);
  		error = ENETDOWN;
  		goto bad;
  	}
  
  	/*
  	 * Enforce how deep the multicast queue can grow.
  	 *
  	 * XXX duplicated in ath_tx_start().
  	 */
  	if (IEEE80211_IS_MULTICAST(wh->i_addr1)) {
  		if (sc->sc_cabq->axq_depth + sc->sc_cabq->fifo.axq_depth
  		    > sc->sc_txq_mcastq_maxdepth) {
  			sc->sc_stats.ast_tx_mcastq_overflow++;
  			error = ENOBUFS;
  		}
  
  		if (error != 0) {
  			m_freem(m);
  			goto bad;
  		}
  	}
  
  	/*
  	 * Grab a TX buffer and associated resources.
  	 */
  	bf = ath_getbuf(sc, ATH_BUFTYPE_MGMT);
  	if (bf == NULL) {
  		sc->sc_stats.ast_tx_nobuf++;
  		m_freem(m);
  		error = ENOBUFS;
  		goto bad;
  	}
  	ATH_KTR(sc, ATH_KTR_TX, 3, "ath_raw_xmit: m=%p, params=%p, bf=%p\n",
  	    m, params,  bf);
  
  	if (params == NULL) {
  		/*
  		 * Legacy path; interpret frame contents to decide
  		 * precisely how to send the frame.
  		 */
  		if (ath_tx_start(sc, ni, bf, m)) {
  			error = EIO;		/* XXX */
  			goto bad2;
  		}
  	} else {
  		/*
  		 * Caller supplied explicit parameters to use in
  		 * sending the frame.
  		 */
  		if (ath_tx_raw_start(sc, ni, bf, m, params)) {
  			error = EIO;		/* XXX */
  			goto bad2;
  		}
  	}
  	sc->sc_wd_timer = 5;
  	sc->sc_stats.ast_tx_raw++;
  
  	/*
  	 * Update the TIM - if there's anything queued to the
  	 * software queue and power save is enabled, we should
  	 * set the TIM.
  	 */
  	ath_tx_update_tim(sc, ni, 1);
  
  	ATH_TX_UNLOCK(sc);
  
  	ATH_PCU_LOCK(sc);
  	sc->sc_txstart_cnt--;
  	ATH_PCU_UNLOCK(sc);
  
  
  	/* Put the hardware back to sleep if required */
  	ATH_LOCK(sc);
  	ath_power_restore_power_state(sc);
  	ATH_UNLOCK(sc);
  
  	return 0;
  
  bad2:
  	ATH_KTR(sc, ATH_KTR_TX, 3, "ath_raw_xmit: bad2: m=%p, params=%p, "
  	    "bf=%p",
  	    m,
  	    params,
  	    bf);
  	ATH_TXBUF_LOCK(sc);
  	ath_returnbuf_head(sc, bf);
  	ATH_TXBUF_UNLOCK(sc);
  
  bad:
  	ATH_TX_UNLOCK(sc);
  
  	ATH_PCU_LOCK(sc);
  	sc->sc_txstart_cnt--;
  	ATH_PCU_UNLOCK(sc);
  
  	/* Put the hardware back to sleep if required */
  	ATH_LOCK(sc);
  	ath_power_restore_power_state(sc);
  	ATH_UNLOCK(sc);
  
  badbad:
  	ATH_KTR(sc, ATH_KTR_TX, 2, "ath_raw_xmit: bad0: m=%p, params=%p",
  	    m, params);
  	sc->sc_stats.ast_tx_raw_fail++;
  
  	return error;
  }
  
  /* Some helper functions */
  
  /*
   * ADDBA (and potentially others) need to be placed in the same
   * hardware queue as the TID/node it's relating to. This is so
   * it goes out after any pending non-aggregate frames to the
   * same node/TID.
   *
   * If this isn't done, the ADDBA can go out before the frames
   * queued in hardware. Even though these frames have a sequence
   * number -earlier- than the ADDBA can be transmitted (but
   * no frames whose sequence numbers are after the ADDBA should
   * be!) they'll arrive after the ADDBA - and the receiving end
   * will simply drop them as being out of the BAW.
   *
   * The frames can't be appended to the TID software queue - it'll
   * never be sent out. So these frames have to be directly
   * dispatched to the hardware, rather than queued in software.
   * So if this function returns true, the TXQ has to be
   * overridden and it has to be directly dispatched.
   *
   * It's a dirty hack, but someone's gotta do it.
   */
  
  /*
   * XXX doesn't belong here!
   */
  static int
  ieee80211_is_action(struct ieee80211_frame *wh)
  {
  	/* Type: Management frame? */
  	if ((wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) !=
  	    IEEE80211_FC0_TYPE_MGT)
  		return 0;
  
  	/* Subtype: Action frame? */
  	if ((wh->i_fc[0] & IEEE80211_FC0_SUBTYPE_MASK) !=
  	    IEEE80211_FC0_SUBTYPE_ACTION)
  		return 0;
  
  	return 1;
  }
  
  #define	MS(_v, _f)	(((_v) & _f) >> _f##_S)
  /*
   * Return an alternate TID for ADDBA request frames.
   *
   * Yes, this likely should be done in the net80211 layer.
   */
  static int
  ath_tx_action_frame_override_queue(struct ath_softc *sc,
      struct ieee80211_node *ni,
      struct mbuf *m0, int *tid)
  {
  	struct ieee80211_frame *wh = mtod(m0, struct ieee80211_frame *);
  	struct ieee80211_action_ba_addbarequest *ia;
  	uint8_t *frm;
  	uint16_t baparamset;
  
  	/* Not action frame? Bail */
  	if (! ieee80211_is_action(wh))
  		return 0;
  
  	/* XXX Not needed for frames we send? */
  #if 0
  	/* Correct length? */
  	if (! ieee80211_parse_action(ni, m))
  		return 0;
  #endif
  
  	/* Extract out action frame */
  	frm = (u_int8_t *)&wh[1];
  	ia = (struct ieee80211_action_ba_addbarequest *) frm;
  
  	/* Not ADDBA? Bail */
  	if (ia->rq_header.ia_category != IEEE80211_ACTION_CAT_BA)
  		return 0;
  	if (ia->rq_header.ia_action != IEEE80211_ACTION_BA_ADDBA_REQUEST)
  		return 0;
  
  	/* Extract TID, return it */
  	baparamset = le16toh(ia->rq_baparamset);
  	*tid = (int) MS(baparamset, IEEE80211_BAPS_TID);
  
  	return 1;
  }
  #undef	MS
  
  /* Per-node software queue operations */
  
  /*
   * Add the current packet to the given BAW.
   * It is assumed that the current packet
   *
   * + fits inside the BAW;
   * + already has had a sequence number allocated.
   *
   * Since the BAW status may be modified by both the ath task and
   * the net80211/ifnet contexts, the TID must be locked.
   */
  void
  ath_tx_addto_baw(struct ath_softc *sc, struct ath_node *an,
      struct ath_tid *tid, struct ath_buf *bf)
  {
  	int index, cindex;
  	struct ieee80211_tx_ampdu *tap;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	if (bf->bf_state.bfs_isretried)
  		return;
  
  	tap = ath_tx_get_tx_tid(an, tid->tid);
  
  	if (! bf->bf_state.bfs_dobaw) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  		    "%s: dobaw=0, seqno=%d, window %d:%d\n",
  		    __func__, SEQNO(bf->bf_state.bfs_seqno),
  		    tap->txa_start, tap->txa_wnd);
  	}
  
  	if (bf->bf_state.bfs_addedbaw)
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  		    "%s: re-added? tid=%d, seqno %d; window %d:%d; "
  		    "baw head=%d tail=%d\n",
  		    __func__, tid->tid, SEQNO(bf->bf_state.bfs_seqno),
  		    tap->txa_start, tap->txa_wnd, tid->baw_head,
  		    tid->baw_tail);
  
  	/*
  	 * Verify that the given sequence number is not outside of the
  	 * BAW.  Complain loudly if that's the case.
  	 */
  	if (! BAW_WITHIN(tap->txa_start, tap->txa_wnd,
  	    SEQNO(bf->bf_state.bfs_seqno))) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  		    "%s: bf=%p: outside of BAW?? tid=%d, seqno %d; window %d:%d; "
  		    "baw head=%d tail=%d\n",
  		    __func__, bf, tid->tid, SEQNO(bf->bf_state.bfs_seqno),
  		    tap->txa_start, tap->txa_wnd, tid->baw_head,
  		    tid->baw_tail);
  	}
  
  	/*
  	 * ni->ni_txseqs[] is the currently allocated seqno.
  	 * the txa state contains the current baw start.
  	 */
  	index  = ATH_BA_INDEX(tap->txa_start, SEQNO(bf->bf_state.bfs_seqno));
  	cindex = (tid->baw_head + index) & (ATH_TID_MAX_BUFS - 1);
  	DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  	    "%s: tid=%d, seqno %d; window %d:%d; index=%d cindex=%d "
  	    "baw head=%d tail=%d\n",
  	    __func__, tid->tid, SEQNO(bf->bf_state.bfs_seqno),
  	    tap->txa_start, tap->txa_wnd, index, cindex, tid->baw_head,
  	    tid->baw_tail);
  
  
  #if 0
  	assert(tid->tx_buf[cindex] == NULL);
  #endif
  	if (tid->tx_buf[cindex] != NULL) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  		    "%s: ba packet dup (index=%d, cindex=%d, "
  		    "head=%d, tail=%d)\n",
  		    __func__, index, cindex, tid->baw_head, tid->baw_tail);
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  		    "%s: BA bf: %p; seqno=%d ; new bf: %p; seqno=%d\n",
  		    __func__,
  		    tid->tx_buf[cindex],
  		    SEQNO(tid->tx_buf[cindex]->bf_state.bfs_seqno),
  		    bf,
  		    SEQNO(bf->bf_state.bfs_seqno)
  		);
  	}
  	tid->tx_buf[cindex] = bf;
  
  	if (index >= ((tid->baw_tail - tid->baw_head) &
  	    (ATH_TID_MAX_BUFS - 1))) {
  		tid->baw_tail = cindex;
  		INCR(tid->baw_tail, ATH_TID_MAX_BUFS);
  	}
  }
  
  /*
   * Flip the BAW buffer entry over from the existing one to the new one.
   *
   * When software retransmitting a (sub-)frame, it is entirely possible that
   * the frame ath_buf is marked as BUSY and can't be immediately reused.
   * In that instance the buffer is cloned and the new buffer is used for
   * retransmit. We thus need to update the ath_buf slot in the BAW buf
   * tracking array to maintain consistency.
   */
  static void
  ath_tx_switch_baw_buf(struct ath_softc *sc, struct ath_node *an,
      struct ath_tid *tid, struct ath_buf *old_bf, struct ath_buf *new_bf)
  {
  	int index, cindex;
  	struct ieee80211_tx_ampdu *tap;
  	int seqno = SEQNO(old_bf->bf_state.bfs_seqno);
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	tap = ath_tx_get_tx_tid(an, tid->tid);
  	index  = ATH_BA_INDEX(tap->txa_start, seqno);
  	cindex = (tid->baw_head + index) & (ATH_TID_MAX_BUFS - 1);
  
  	/*
  	 * Just warn for now; if it happens then we should find out
  	 * about it. It's highly likely the aggregation session will
  	 * soon hang.
  	 */
  	if (old_bf->bf_state.bfs_seqno != new_bf->bf_state.bfs_seqno) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  		    "%s: retransmitted buffer"
  		    " has mismatching seqno's, BA session may hang.\n",
  		    __func__);
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  		    "%s: old seqno=%d, new_seqno=%d\n", __func__,
  		    old_bf->bf_state.bfs_seqno, new_bf->bf_state.bfs_seqno);
  	}
  
  	if (tid->tx_buf[cindex] != old_bf) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  		    "%s: ath_buf pointer incorrect; "
  		    " has m BA session may hang.\n", __func__);
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  		    "%s: old bf=%p, new bf=%p\n", __func__, old_bf, new_bf);
  	}
  
  	tid->tx_buf[cindex] = new_bf;
  }
  
  /*
   * seq_start - left edge of BAW
   * seq_next - current/next sequence number to allocate
   *
   * Since the BAW status may be modified by both the ath task and
   * the net80211/ifnet contexts, the TID must be locked.
   */
  static void
  ath_tx_update_baw(struct ath_softc *sc, struct ath_node *an,
      struct ath_tid *tid, const struct ath_buf *bf)
  {
  	int index, cindex;
  	struct ieee80211_tx_ampdu *tap;
  	int seqno = SEQNO(bf->bf_state.bfs_seqno);
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	tap = ath_tx_get_tx_tid(an, tid->tid);
  	index  = ATH_BA_INDEX(tap->txa_start, seqno);
  	cindex = (tid->baw_head + index) & (ATH_TID_MAX_BUFS - 1);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  	    "%s: tid=%d, baw=%d:%d, seqno=%d, index=%d, cindex=%d, "
  	    "baw head=%d, tail=%d\n",
  	    __func__, tid->tid, tap->txa_start, tap->txa_wnd, seqno, index,
  	    cindex, tid->baw_head, tid->baw_tail);
  
  	/*
  	 * If this occurs then we have a big problem - something else
  	 * has slid tap->txa_start along without updating the BAW
  	 * tracking start/end pointers. Thus the TX BAW state is now
  	 * completely busted.
  	 *
  	 * But for now, since I haven't yet fixed TDMA and buffer cloning,
  	 * it's quite possible that a cloned buffer is making its way
  	 * here and causing it to fire off. Disable TDMA for now.
  	 */
  	if (tid->tx_buf[cindex] != bf) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  		    "%s: comp bf=%p, seq=%d; slot bf=%p, seqno=%d\n",
  		    __func__, bf, SEQNO(bf->bf_state.bfs_seqno),
  		    tid->tx_buf[cindex],
  		    (tid->tx_buf[cindex] != NULL) ?
  		      SEQNO(tid->tx_buf[cindex]->bf_state.bfs_seqno) : -1);
  	}
  
  	tid->tx_buf[cindex] = NULL;
  
  	while (tid->baw_head != tid->baw_tail &&
  	    !tid->tx_buf[tid->baw_head]) {
  		INCR(tap->txa_start, IEEE80211_SEQ_RANGE);
  		INCR(tid->baw_head, ATH_TID_MAX_BUFS);
  	}
  	DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  	    "%s: tid=%d: baw is now %d:%d, baw head=%d\n",
  	    __func__, tid->tid, tap->txa_start, tap->txa_wnd, tid->baw_head);
  }
  
  static void
  ath_tx_leak_count_update(struct ath_softc *sc, struct ath_tid *tid,
      struct ath_buf *bf)
  {
  	struct ieee80211_frame *wh;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	if (tid->an->an_leak_count > 0) {
  		wh = mtod(bf->bf_m, struct ieee80211_frame *);
  
  		/*
  		 * Update MORE based on the software/net80211 queue states.
  		 */
  		if ((tid->an->an_stack_psq > 0)
  		    || (tid->an->an_swq_depth > 0))
  			wh->i_fc[1] |= IEEE80211_FC1_MORE_DATA;
  		else
  			wh->i_fc[1] &= ~IEEE80211_FC1_MORE_DATA;
  
  		DPRINTF(sc, ATH_DEBUG_NODE_PWRSAVE,
  		    "%s: %6D: leak count = %d, psq=%d, swq=%d, MORE=%d\n",
  		    __func__,
  		    tid->an->an_node.ni_macaddr,
  		    ":",
  		    tid->an->an_leak_count,
  		    tid->an->an_stack_psq,
  		    tid->an->an_swq_depth,
  		    !! (wh->i_fc[1] & IEEE80211_FC1_MORE_DATA));
  
  		/*
  		 * Re-sync the underlying buffer.
  		 */
  		bus_dmamap_sync(sc->sc_dmat, bf->bf_dmamap,
  		    BUS_DMASYNC_PREWRITE);
  
  		tid->an->an_leak_count --;
  	}
  }
  
  static int
  ath_tx_tid_can_tx_or_sched(struct ath_softc *sc, struct ath_tid *tid)
  {
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	if (tid->an->an_leak_count > 0) {
  		return (1);
  	}
  	if (tid->paused)
  		return (0);
  	return (1);
  }
  
  /*
   * Mark the current node/TID as ready to TX.
   *
   * This is done to make it easy for the software scheduler to
   * find which nodes have data to send.
   *
   * The TXQ lock must be held.
   */
  void
  ath_tx_tid_sched(struct ath_softc *sc, struct ath_tid *tid)
  {
  	struct ath_txq *txq = sc->sc_ac2q[tid->ac];
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/*
  	 * If we are leaking out a frame to this destination
  	 * for PS-POLL, ensure that we allow scheduling to
  	 * occur.
  	 */
  	if (! ath_tx_tid_can_tx_or_sched(sc, tid))
  		return;		/* paused, can't schedule yet */
  
  	if (tid->sched)
  		return;		/* already scheduled */
  
  	tid->sched = 1;
  
  #if 0
  	/*
  	 * If this is a sleeping node we're leaking to, given
  	 * it a higher priority.  This is so bad for QoS it hurts.
  	 */
  	if (tid->an->an_leak_count) {
  		TAILQ_INSERT_HEAD(&txq->axq_tidq, tid, axq_qelem);
  	} else {
  		TAILQ_INSERT_TAIL(&txq->axq_tidq, tid, axq_qelem);
  	}
  #endif
  
  	/*
  	 * We can't do the above - it'll confuse the TXQ software
  	 * scheduler which will keep checking the _head_ TID
  	 * in the list to see if it has traffic.  If we queue
  	 * a TID to the head of the list and it doesn't transmit,
  	 * we'll check it again.
  	 *
  	 * So, get the rest of this leaking frames support working
  	 * and reliable first and _then_ optimise it so they're
  	 * pushed out in front of any other pending software
  	 * queued nodes.
  	 */
  	TAILQ_INSERT_TAIL(&txq->axq_tidq, tid, axq_qelem);
  }
  
  /*
   * Mark the current node as no longer needing to be polled for
   * TX packets.
   *
   * The TXQ lock must be held.
   */
  static void
  ath_tx_tid_unsched(struct ath_softc *sc, struct ath_tid *tid)
  {
  	struct ath_txq *txq = sc->sc_ac2q[tid->ac];
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	if (tid->sched == 0)
  		return;
  
  	tid->sched = 0;
  	TAILQ_REMOVE(&txq->axq_tidq, tid, axq_qelem);
  }
  
  /*
   * Assign a sequence number manually to the given frame.
   *
   * This should only be called for A-MPDU TX frames.
   */
  static ieee80211_seq
  ath_tx_tid_seqno_assign(struct ath_softc *sc, struct ieee80211_node *ni,
      struct ath_buf *bf, struct mbuf *m0)
  {
  	struct ieee80211_frame *wh;
  	int tid, pri;
  	ieee80211_seq seqno;
  	uint8_t subtype;
  
  	/* TID lookup */
  	wh = mtod(m0, struct ieee80211_frame *);
  	pri = M_WME_GETAC(m0);			/* honor classification */
  	tid = WME_AC_TO_TID(pri);
  	DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: pri=%d, tid=%d, qos has seq=%d\n",
  	    __func__, pri, tid, IEEE80211_QOS_HAS_SEQ(wh));
  
  	/* XXX Is it a control frame? Ignore */
  
  	/* Does the packet require a sequence number? */
  	if (! IEEE80211_QOS_HAS_SEQ(wh))
  		return -1;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/*
  	 * Is it a QOS NULL Data frame? Give it a sequence number from
  	 * the default TID (IEEE80211_NONQOS_TID.)
  	 *
  	 * The RX path of everything I've looked at doesn't include the NULL
  	 * data frame sequence number in the aggregation state updates, so
  	 * assigning it a sequence number there will cause a BAW hole on the
  	 * RX side.
  	 */
  	subtype = wh->i_fc[0] & IEEE80211_FC0_SUBTYPE_MASK;
  	if (subtype == IEEE80211_FC0_SUBTYPE_QOS_NULL) {
  		/* XXX no locking for this TID? This is a bit of a problem. */
  		seqno = ni->ni_txseqs[IEEE80211_NONQOS_TID];
  		INCR(ni->ni_txseqs[IEEE80211_NONQOS_TID], IEEE80211_SEQ_RANGE);
  	} else {
  		/* Manually assign sequence number */
  		seqno = ni->ni_txseqs[tid];
  		INCR(ni->ni_txseqs[tid], IEEE80211_SEQ_RANGE);
  	}
  	*(uint16_t *)&wh->i_seq[0] = htole16(seqno << IEEE80211_SEQ_SEQ_SHIFT);
  	M_SEQNO_SET(m0, seqno);
  
  	/* Return so caller can do something with it if needed */
  	DPRINTF(sc, ATH_DEBUG_SW_TX, "%s:  -> seqno=%d\n", __func__, seqno);
  	return seqno;
  }
  
  /*
   * Attempt to direct dispatch an aggregate frame to hardware.
   * If the frame is out of BAW, queue.
   * Otherwise, schedule it as a single frame.
   */
  static void
  ath_tx_xmit_aggr(struct ath_softc *sc, struct ath_node *an,
      struct ath_txq *txq, struct ath_buf *bf)
  {
  	struct ath_tid *tid = &an->an_tid[bf->bf_state.bfs_tid];
  	struct ieee80211_tx_ampdu *tap;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	tap = ath_tx_get_tx_tid(an, tid->tid);
  
  	/* paused? queue */
  	if (! ath_tx_tid_can_tx_or_sched(sc, tid)) {
  		ATH_TID_INSERT_HEAD(tid, bf, bf_list);
  		/* XXX don't sched - we're paused! */
  		return;
  	}
  
  	/* outside baw? queue */
  	if (bf->bf_state.bfs_dobaw &&
  	    (! BAW_WITHIN(tap->txa_start, tap->txa_wnd,
  	    SEQNO(bf->bf_state.bfs_seqno)))) {
  		ATH_TID_INSERT_HEAD(tid, bf, bf_list);
  		ath_tx_tid_sched(sc, tid);
  		return;
  	}
  
  	/*
  	 * This is a temporary check and should be removed once
  	 * all the relevant code paths have been fixed.
  	 *
  	 * During aggregate retries, it's possible that the head
  	 * frame will fail (which has the bfs_aggr and bfs_nframes
  	 * fields set for said aggregate) and will be retried as
  	 * a single frame.  In this instance, the values should
  	 * be reset or the completion code will get upset with you.
  	 */
  	if (bf->bf_state.bfs_aggr != 0 || bf->bf_state.bfs_nframes > 1) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  		    "%s: bfs_aggr=%d, bfs_nframes=%d\n", __func__,
  		    bf->bf_state.bfs_aggr, bf->bf_state.bfs_nframes);
  		bf->bf_state.bfs_aggr = 0;
  		bf->bf_state.bfs_nframes = 1;
  	}
  
  	/* Update CLRDMASK just before this frame is queued */
  	ath_tx_update_clrdmask(sc, tid, bf);
  
  	/* Direct dispatch to hardware */
  	ath_tx_do_ratelookup(sc, bf);
  	ath_tx_calc_duration(sc, bf);
  	ath_tx_calc_protection(sc, bf);
  	ath_tx_set_rtscts(sc, bf);
  	ath_tx_rate_fill_rcflags(sc, bf);
  	ath_tx_setds(sc, bf);
  
  	/* Statistics */
  	sc->sc_aggr_stats.aggr_low_hwq_single_pkt++;
  
  	/* Track per-TID hardware queue depth correctly */
  	tid->hwq_depth++;
  
  	/* Add to BAW */
  	if (bf->bf_state.bfs_dobaw) {
  		ath_tx_addto_baw(sc, an, tid, bf);
  		bf->bf_state.bfs_addedbaw = 1;
  	}
  
  	/* Set completion handler, multi-frame aggregate or not */
  	bf->bf_comp = ath_tx_aggr_comp;
  
  	/*
  	 * Update the current leak count if
  	 * we're leaking frames; and set the
  	 * MORE flag as appropriate.
  	 */
  	ath_tx_leak_count_update(sc, tid, bf);
  
  	/* Hand off to hardware */
  	ath_tx_handoff(sc, txq, bf);
  }
  
  /*
   * Attempt to send the packet.
   * If the queue isn't busy, direct-dispatch.
   * If the queue is busy enough, queue the given packet on the
   *  relevant software queue.
   */
  void
  ath_tx_swq(struct ath_softc *sc, struct ieee80211_node *ni,
      struct ath_txq *txq, int queue_to_head, struct ath_buf *bf)
  {
  	struct ath_node *an = ATH_NODE(ni);
  	struct ieee80211_frame *wh;
  	struct ath_tid *atid;
  	int pri, tid;
  	struct mbuf *m0 = bf->bf_m;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/* Fetch the TID - non-QoS frames get assigned to TID 16 */
  	wh = mtod(m0, struct ieee80211_frame *);
  	pri = ath_tx_getac(sc, m0);
  	tid = ath_tx_gettid(sc, m0);
  	atid = &an->an_tid[tid];
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: bf=%p, pri=%d, tid=%d, qos=%d\n",
  	    __func__, bf, pri, tid, IEEE80211_QOS_HAS_SEQ(wh));
  
  	/* Set local packet state, used to queue packets to hardware */
  	/* XXX potentially duplicate info, re-check */
  	bf->bf_state.bfs_tid = tid;
  	bf->bf_state.bfs_tx_queue = txq->axq_qnum;
  	bf->bf_state.bfs_pri = pri;
  
  	/*
  	 * If the hardware queue isn't busy, queue it directly.
  	 * If the hardware queue is busy, queue it.
  	 * If the TID is paused or the traffic it outside BAW, software
  	 * queue it.
  	 *
  	 * If the node is in power-save and we're leaking a frame,
  	 * leak a single frame.
  	 */
  	if (! ath_tx_tid_can_tx_or_sched(sc, atid)) {
  		/* TID is paused, queue */
  		DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: paused\n", __func__);
  		/*
  		 * If the caller requested that it be sent at a high
  		 * priority, queue it at the head of the list.
  		 */
  		if (queue_to_head)
  			ATH_TID_INSERT_HEAD(atid, bf, bf_list);
  		else
  			ATH_TID_INSERT_TAIL(atid, bf, bf_list);
  	} else if (ath_tx_ampdu_pending(sc, an, tid)) {
  		/* AMPDU pending; queue */
  		DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: pending\n", __func__);
  		ATH_TID_INSERT_TAIL(atid, bf, bf_list);
  		/* XXX sched? */
  	} else if (ath_tx_ampdu_running(sc, an, tid)) {
  		/* AMPDU running, attempt direct dispatch if possible */
  
  		/*
  		 * Always queue the frame to the tail of the list.
  		 */
  		ATH_TID_INSERT_TAIL(atid, bf, bf_list);
  
  		/*
  		 * If the hardware queue isn't busy, direct dispatch
  		 * the head frame in the list.  Don't schedule the
  		 * TID - let it build some more frames first?
  		 *
  		 * When running A-MPDU, always just check the hardware
  		 * queue depth against the aggregate frame limit.
  		 * We don't want to burst a large number of single frames
  		 * out to the hardware; we want to aggressively hold back.
  		 *
  		 * Otherwise, schedule the TID.
  		 */
  		/* XXX TXQ locking */
  		if (txq->axq_depth + txq->fifo.axq_depth < sc->sc_hwq_limit_aggr) {
  			bf = ATH_TID_FIRST(atid);
  			ATH_TID_REMOVE(atid, bf, bf_list);
  
  			/*
  			 * Ensure it's definitely treated as a non-AMPDU
  			 * frame - this information may have been left
  			 * over from a previous attempt.
  			 */
  			bf->bf_state.bfs_aggr = 0;
  			bf->bf_state.bfs_nframes = 1;
  
  			/* Queue to the hardware */
  			ath_tx_xmit_aggr(sc, an, txq, bf);
  			DPRINTF(sc, ATH_DEBUG_SW_TX,
  			    "%s: xmit_aggr\n",
  			    __func__);
  		} else {
  			DPRINTF(sc, ATH_DEBUG_SW_TX,
  			    "%s: ampdu; swq'ing\n",
  			    __func__);
  
  			ath_tx_tid_sched(sc, atid);
  		}
  	/*
  	 * If we're not doing A-MPDU, be prepared to direct dispatch
  	 * up to both limits if possible.  This particular corner
  	 * case may end up with packet starvation between aggregate
  	 * traffic and non-aggregate traffic: we want to ensure
  	 * that non-aggregate stations get a few frames queued to the
  	 * hardware before the aggregate station(s) get their chance.
  	 *
  	 * So if you only ever see a couple of frames direct dispatched
  	 * to the hardware from a non-AMPDU client, check both here
  	 * and in the software queue dispatcher to ensure that those
  	 * non-AMPDU stations get a fair chance to transmit.
  	 */
  	/* XXX TXQ locking */
  	} else if ((txq->axq_depth + txq->fifo.axq_depth < sc->sc_hwq_limit_nonaggr) &&
  		    (txq->axq_aggr_depth < sc->sc_hwq_limit_aggr)) {
  		/* AMPDU not running, attempt direct dispatch */
  		DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: xmit_normal\n", __func__);
  		/* See if clrdmask needs to be set */
  		ath_tx_update_clrdmask(sc, atid, bf);
  
  		/*
  		 * Update the current leak count if
  		 * we're leaking frames; and set the
  		 * MORE flag as appropriate.
  		 */
  		ath_tx_leak_count_update(sc, atid, bf);
  
  		/*
  		 * Dispatch the frame.
  		 */
  		ath_tx_xmit_normal(sc, txq, bf);
  	} else {
  		/* Busy; queue */
  		DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: swq'ing\n", __func__);
  		ATH_TID_INSERT_TAIL(atid, bf, bf_list);
  		ath_tx_tid_sched(sc, atid);
  	}
  }
  
  /*
   * Only set the clrdmask bit if none of the nodes are currently
   * filtered.
   *
   * XXX TODO: go through all the callers and check to see
   * which are being called in the context of looping over all
   * TIDs (eg, if all tids are being paused, resumed, etc.)
   * That'll avoid O(n^2) complexity here.
   */
  static void
  ath_tx_set_clrdmask(struct ath_softc *sc, struct ath_node *an)
  {
  	int i;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	for (i = 0; i < IEEE80211_TID_SIZE; i++) {
  		if (an->an_tid[i].isfiltered == 1)
  			return;
  	}
  	an->clrdmask = 1;
  }
  
  /*
   * Configure the per-TID node state.
   *
   * This likely belongs in if_ath_node.c but I can't think of anywhere
   * else to put it just yet.
   *
   * This sets up the SLISTs and the mutex as appropriate.
   */
  void
  ath_tx_tid_init(struct ath_softc *sc, struct ath_node *an)
  {
  	int i, j;
  	struct ath_tid *atid;
  
  	for (i = 0; i < IEEE80211_TID_SIZE; i++) {
  		atid = &an->an_tid[i];
  
  		/* XXX now with this bzer(), is the field 0'ing needed? */
  		bzero(atid, sizeof(*atid));
  
  		TAILQ_INIT(&atid->tid_q);
  		TAILQ_INIT(&atid->filtq.tid_q);
  		atid->tid = i;
  		atid->an = an;
  		for (j = 0; j < ATH_TID_MAX_BUFS; j++)
  			atid->tx_buf[j] = NULL;
  		atid->baw_head = atid->baw_tail = 0;
  		atid->paused = 0;
  		atid->sched = 0;
  		atid->hwq_depth = 0;
  		atid->cleanup_inprogress = 0;
  		if (i == IEEE80211_NONQOS_TID)
  			atid->ac = ATH_NONQOS_TID_AC;
  		else
  			atid->ac = TID_TO_WME_AC(i);
  	}
  	an->clrdmask = 1;	/* Always start by setting this bit */
  }
  
  /*
   * Pause the current TID. This stops packets from being transmitted
   * on it.
   *
   * Since this is also called from upper layers as well as the driver,
   * it will get the TID lock.
   */
  static void
  ath_tx_tid_pause(struct ath_softc *sc, struct ath_tid *tid)
  {
  
  	ATH_TX_LOCK_ASSERT(sc);
  	tid->paused++;
  	DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL, "%s: [%6D]: tid=%d, paused = %d\n",
  	    __func__,
  	    tid->an->an_node.ni_macaddr, ":",
  	    tid->tid,
  	    tid->paused);
  }
  
  /*
   * Unpause the current TID, and schedule it if needed.
   */
  static void
  ath_tx_tid_resume(struct ath_softc *sc, struct ath_tid *tid)
  {
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/*
  	 * There's some odd places where ath_tx_tid_resume() is called
  	 * when it shouldn't be; this works around that particular issue
  	 * until it's actually resolved.
  	 */
  	if (tid->paused == 0) {
  		device_printf(sc->sc_dev,
  		    "%s: [%6D]: tid=%d, paused=0?\n",
  		    __func__,
  		    tid->an->an_node.ni_macaddr, ":",
  		    tid->tid);
  	} else {
  		tid->paused--;
  	}
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL,
  	    "%s: [%6D]: tid=%d, unpaused = %d\n",
  	    __func__,
  	    tid->an->an_node.ni_macaddr, ":",
  	    tid->tid,
  	    tid->paused);
  
  	if (tid->paused)
  		return;
  
  	/*
  	 * Override the clrdmask configuration for the next frame
  	 * from this TID, just to get the ball rolling.
  	 */
  	ath_tx_set_clrdmask(sc, tid->an);
  
  	if (tid->axq_depth == 0)
  		return;
  
  	/* XXX isfiltered shouldn't ever be 0 at this point */
  	if (tid->isfiltered == 1) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL, "%s: filtered?!\n",
  		    __func__);
  		return;
  	}
  
  	ath_tx_tid_sched(sc, tid);
  
  	/*
  	 * Queue the software TX scheduler.
  	 */
  	ath_tx_swq_kick(sc);
  }
  
  /*
   * Add the given ath_buf to the TID filtered frame list.
   * This requires the TID be filtered.
   */
  static void
  ath_tx_tid_filt_addbuf(struct ath_softc *sc, struct ath_tid *tid,
      struct ath_buf *bf)
  {
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	if (!tid->isfiltered)
  		DPRINTF(sc, ATH_DEBUG_SW_TX_FILT, "%s: not filtered?!\n",
  		    __func__);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_FILT, "%s: bf=%p\n", __func__, bf);
  
  	/* Set the retry bit and bump the retry counter */
  	ath_tx_set_retry(sc, bf);
  	sc->sc_stats.ast_tx_swfiltered++;
  
  	ATH_TID_FILT_INSERT_TAIL(tid, bf, bf_list);
  }
  
  /*
   * Handle a completed filtered frame from the given TID.
   * This just enables/pauses the filtered frame state if required
   * and appends the filtered frame to the filtered queue.
   */
  static void
  ath_tx_tid_filt_comp_buf(struct ath_softc *sc, struct ath_tid *tid,
      struct ath_buf *bf)
  {
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	if (! tid->isfiltered) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_FILT, "%s: tid=%d; filter transition\n",
  		    __func__, tid->tid);
  		tid->isfiltered = 1;
  		ath_tx_tid_pause(sc, tid);
  	}
  
  	/* Add the frame to the filter queue */
  	ath_tx_tid_filt_addbuf(sc, tid, bf);
  }
  
  /*
   * Complete the filtered frame TX completion.
   *
   * If there are no more frames in the hardware queue, unpause/unfilter
   * the TID if applicable.  Otherwise we will wait for a node PS transition
   * to unfilter.
   */
  static void
  ath_tx_tid_filt_comp_complete(struct ath_softc *sc, struct ath_tid *tid)
  {
  	struct ath_buf *bf;
  	int do_resume = 0;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	if (tid->hwq_depth != 0)
  		return;
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_FILT, "%s: tid=%d, hwq=0, transition back\n",
  	    __func__, tid->tid);
  	if (tid->isfiltered == 1) {
  		tid->isfiltered = 0;
  		do_resume = 1;
  	}
  
  	/* XXX ath_tx_tid_resume() also calls ath_tx_set_clrdmask()! */
  	ath_tx_set_clrdmask(sc, tid->an);
  
  	/* XXX this is really quite inefficient */
  	while ((bf = ATH_TID_FILT_LAST(tid, ath_bufhead_s)) != NULL) {
  		ATH_TID_FILT_REMOVE(tid, bf, bf_list);
  		ATH_TID_INSERT_HEAD(tid, bf, bf_list);
  	}
  
  	/* And only resume if we had paused before */
  	if (do_resume)
  		ath_tx_tid_resume(sc, tid);
  }
  
  /*
   * Called when a single (aggregate or otherwise) frame is completed.
   *
   * Returns 0 if the buffer could be added to the filtered list
   * (cloned or otherwise), 1 if the buffer couldn't be added to the
   * filtered list (failed clone; expired retry) and the caller should
   * free it and handle it like a failure (eg by sending a BAR.)
   *
   * since the buffer may be cloned, bf must be not touched after this
   * if the return value is 0.
   */
  static int
  ath_tx_tid_filt_comp_single(struct ath_softc *sc, struct ath_tid *tid,
      struct ath_buf *bf)
  {
  	struct ath_buf *nbf;
  	int retval;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/*
  	 * Don't allow a filtered frame to live forever.
  	 */
  	if (bf->bf_state.bfs_retries > SWMAX_RETRIES) {
  		sc->sc_stats.ast_tx_swretrymax++;
  		DPRINTF(sc, ATH_DEBUG_SW_TX_FILT,
  		    "%s: bf=%p, seqno=%d, exceeded retries\n",
  		    __func__,
  		    bf,
  		    SEQNO(bf->bf_state.bfs_seqno));
  		retval = 1; /* error */
  		goto finish;
  	}
  
  	/*
  	 * A busy buffer can't be added to the retry list.
  	 * It needs to be cloned.
  	 */
  	if (bf->bf_flags & ATH_BUF_BUSY) {
  		nbf = ath_tx_retry_clone(sc, tid->an, tid, bf);
  		DPRINTF(sc, ATH_DEBUG_SW_TX_FILT,
  		    "%s: busy buffer clone: %p -> %p\n",
  		    __func__, bf, nbf);
  	} else {
  		nbf = bf;
  	}
  
  	if (nbf == NULL) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_FILT,
  		    "%s: busy buffer couldn't be cloned (%p)!\n",
  		    __func__, bf);
  		retval = 1; /* error */
  	} else {
  		ath_tx_tid_filt_comp_buf(sc, tid, nbf);
  		retval = 0; /* ok */
  	}
  finish:
  	ath_tx_tid_filt_comp_complete(sc, tid);
  
  	return (retval);
  }
  
  static void
  ath_tx_tid_filt_comp_aggr(struct ath_softc *sc, struct ath_tid *tid,
      struct ath_buf *bf_first, ath_bufhead *bf_q)
  {
  	struct ath_buf *bf, *bf_next, *nbf;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	bf = bf_first;
  	while (bf) {
  		bf_next = bf->bf_next;
  		bf->bf_next = NULL;	/* Remove it from the aggr list */
  
  		/*
  		 * Don't allow a filtered frame to live forever.
  		 */
  		if (bf->bf_state.bfs_retries > SWMAX_RETRIES) {
  			sc->sc_stats.ast_tx_swretrymax++;
  			DPRINTF(sc, ATH_DEBUG_SW_TX_FILT,
  			    "%s: tid=%d, bf=%p, seqno=%d, exceeded retries\n",
  			    __func__,
  			    tid->tid,
  			    bf,
  			    SEQNO(bf->bf_state.bfs_seqno));
  			TAILQ_INSERT_TAIL(bf_q, bf, bf_list);
  			goto next;
  		}
  
  		if (bf->bf_flags & ATH_BUF_BUSY) {
  			nbf = ath_tx_retry_clone(sc, tid->an, tid, bf);
  			DPRINTF(sc, ATH_DEBUG_SW_TX_FILT,
  			    "%s: tid=%d, busy buffer cloned: %p -> %p, seqno=%d\n",
  			    __func__, tid->tid, bf, nbf, SEQNO(bf->bf_state.bfs_seqno));
  		} else {
  			nbf = bf;
  		}
  
  		/*
  		 * If the buffer couldn't be cloned, add it to bf_q;
  		 * the caller will free the buffer(s) as required.
  		 */
  		if (nbf == NULL) {
  			DPRINTF(sc, ATH_DEBUG_SW_TX_FILT,
  			    "%s: tid=%d, buffer couldn't be cloned! (%p) seqno=%d\n",
  			    __func__, tid->tid, bf, SEQNO(bf->bf_state.bfs_seqno));
  			TAILQ_INSERT_TAIL(bf_q, bf, bf_list);
  		} else {
  			ath_tx_tid_filt_comp_buf(sc, tid, nbf);
  		}
  next:
  		bf = bf_next;
  	}
  
  	ath_tx_tid_filt_comp_complete(sc, tid);
  }
  
  /*
   * Suspend the queue because we need to TX a BAR.
   */
  static void
  ath_tx_tid_bar_suspend(struct ath_softc *sc, struct ath_tid *tid)
  {
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_BAR,
  	    "%s: tid=%d, bar_wait=%d, bar_tx=%d, called\n",
  	    __func__,
  	    tid->tid,
  	    tid->bar_wait,
  	    tid->bar_tx);
  
  	/* We shouldn't be called when bar_tx is 1 */
  	if (tid->bar_tx) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAR,
  		    "%s: bar_tx is 1?!\n", __func__);
  	}
  
  	/* If we've already been called, just be patient. */
  	if (tid->bar_wait)
  		return;
  
  	/* Wait! */
  	tid->bar_wait = 1;
  
  	/* Only one pause, no matter how many frames fail */
  	ath_tx_tid_pause(sc, tid);
  }
  
  /*
   * We've finished with BAR handling - either we succeeded or
   * failed. Either way, unsuspend TX.
   */
  static void
  ath_tx_tid_bar_unsuspend(struct ath_softc *sc, struct ath_tid *tid)
  {
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_BAR,
  	    "%s: %6D: TID=%d, called\n",
  	    __func__,
  	    tid->an->an_node.ni_macaddr,
  	    ":",
  	    tid->tid);
  
  	if (tid->bar_tx == 0 || tid->bar_wait == 0) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAR,
  		    "%s: %6D: TID=%d, bar_tx=%d, bar_wait=%d: ?\n",
  		    __func__, tid->an->an_node.ni_macaddr, ":",
  		    tid->tid, tid->bar_tx, tid->bar_wait);
  	}
  
  	tid->bar_tx = tid->bar_wait = 0;
  	ath_tx_tid_resume(sc, tid);
  }
  
  /*
   * Return whether we're ready to TX a BAR frame.
   *
   * Requires the TID lock be held.
   */
  static int
  ath_tx_tid_bar_tx_ready(struct ath_softc *sc, struct ath_tid *tid)
  {
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	if (tid->bar_wait == 0 || tid->hwq_depth > 0)
  		return (0);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_BAR,
  	    "%s: %6D: TID=%d, bar ready\n",
  	    __func__,
  	    tid->an->an_node.ni_macaddr,
  	    ":",
  	    tid->tid);
  
  	return (1);
  }
  
  /*
   * Check whether the current TID is ready to have a BAR
   * TXed and if so, do the TX.
   *
   * Since the TID/TXQ lock can't be held during a call to
   * ieee80211_send_bar(), we have to do the dirty thing of unlocking it,
   * sending the BAR and locking it again.
   *
   * Eventually, the code to send the BAR should be broken out
   * from this routine so the lock doesn't have to be reacquired
   * just to be immediately dropped by the caller.
   */
  static void
  ath_tx_tid_bar_tx(struct ath_softc *sc, struct ath_tid *tid)
  {
  	struct ieee80211_tx_ampdu *tap;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_BAR,
  	    "%s: %6D: TID=%d, called\n",
  	    __func__,
  	    tid->an->an_node.ni_macaddr,
  	    ":",
  	    tid->tid);
  
  	tap = ath_tx_get_tx_tid(tid->an, tid->tid);
  
  	/*
  	 * This is an error condition!
  	 */
  	if (tid->bar_wait == 0 || tid->bar_tx == 1) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAR,
  		    "%s: %6D: TID=%d, bar_tx=%d, bar_wait=%d: ?\n",
  		    __func__, tid->an->an_node.ni_macaddr, ":",
  		    tid->tid, tid->bar_tx, tid->bar_wait);
  		return;
  	}
  
  	/* Don't do anything if we still have pending frames */
  	if (tid->hwq_depth > 0) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_BAR,
  		    "%s: %6D: TID=%d, hwq_depth=%d, waiting\n",
  		    __func__,
  		    tid->an->an_node.ni_macaddr,
  		    ":",
  		    tid->tid,
  		    tid->hwq_depth);
  		return;
  	}
  
  	/* We're now about to TX */
  	tid->bar_tx = 1;
  
  	/*
  	 * Override the clrdmask configuration for the next frame,
  	 * just to get the ball rolling.
  	 */
  	ath_tx_set_clrdmask(sc, tid->an);
  
  	/*
  	 * Calculate new BAW left edge, now that all frames have either
  	 * succeeded or failed.
  	 *
  	 * XXX verify this is _actually_ the valid value to begin at!
  	 */
  	DPRINTF(sc, ATH_DEBUG_SW_TX_BAR,
  	    "%s: %6D: TID=%d, new BAW left edge=%d\n",
  	    __func__,
  	    tid->an->an_node.ni_macaddr,
  	    ":",
  	    tid->tid,
  	    tap->txa_start);
  
  	/* Try sending the BAR frame */
  	/* We can't hold the lock here! */
  
  	ATH_TX_UNLOCK(sc);
  	if (ieee80211_send_bar(&tid->an->an_node, tap, tap->txa_start) == 0) {
  		/* Success? Now we wait for notification that it's done */
  		ATH_TX_LOCK(sc);
  		return;
  	}
  
  	/* Failure? For now, warn loudly and continue */
  	ATH_TX_LOCK(sc);
  	DPRINTF(sc, ATH_DEBUG_SW_TX_BAR,
  	    "%s: %6D: TID=%d, failed to TX BAR, continue!\n",
  	    __func__, tid->an->an_node.ni_macaddr, ":",
  	    tid->tid);
  	ath_tx_tid_bar_unsuspend(sc, tid);
  }
  
  static void
  ath_tx_tid_drain_pkt(struct ath_softc *sc, struct ath_node *an,
      struct ath_tid *tid, ath_bufhead *bf_cq, struct ath_buf *bf)
  {
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/*
  	 * If the current TID is running AMPDU, update
  	 * the BAW.
  	 */
  	if (ath_tx_ampdu_running(sc, an, tid->tid) &&
  	    bf->bf_state.bfs_dobaw) {
  		/*
  		 * Only remove the frame from the BAW if it's
  		 * been transmitted at least once; this means
  		 * the frame was in the BAW to begin with.
  		 */
  		if (bf->bf_state.bfs_retries > 0) {
  			ath_tx_update_baw(sc, an, tid, bf);
  			bf->bf_state.bfs_dobaw = 0;
  		}
  #if 0
  		/*
  		 * This has become a non-fatal error now
  		 */
  		if (! bf->bf_state.bfs_addedbaw)
  			DPRINTF(sc, ATH_DEBUG_SW_TX_BAW
  			    "%s: wasn't added: seqno %d\n",
  			    __func__, SEQNO(bf->bf_state.bfs_seqno));
  #endif
  	}
  
  	/* Strip it out of an aggregate list if it was in one */
  	bf->bf_next = NULL;
  
  	/* Insert on the free queue to be freed by the caller */
  	TAILQ_INSERT_TAIL(bf_cq, bf, bf_list);
  }
  
  static void
  ath_tx_tid_drain_print(struct ath_softc *sc, struct ath_node *an,
      const char *pfx, struct ath_tid *tid, struct ath_buf *bf)
  {
  	struct ieee80211_node *ni = &an->an_node;
  	struct ath_txq *txq;
  	struct ieee80211_tx_ampdu *tap;
  
  	txq = sc->sc_ac2q[tid->ac];
  	tap = ath_tx_get_tx_tid(an, tid->tid);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX | ATH_DEBUG_RESET,
  	    "%s: %s: %6D: bf=%p: addbaw=%d, dobaw=%d, "
  	    "seqno=%d, retry=%d\n",
  	    __func__,
  	    pfx,
  	    ni->ni_macaddr,
  	    ":",
  	    bf,
  	    bf->bf_state.bfs_addedbaw,
  	    bf->bf_state.bfs_dobaw,
  	    SEQNO(bf->bf_state.bfs_seqno),
  	    bf->bf_state.bfs_retries);
  	DPRINTF(sc, ATH_DEBUG_SW_TX | ATH_DEBUG_RESET,
  	    "%s: %s: %6D: bf=%p: txq[%d] axq_depth=%d, axq_aggr_depth=%d\n",
  	    __func__,
  	    pfx,
  	    ni->ni_macaddr,
  	    ":",
  	    bf,
  	    txq->axq_qnum,
  	    txq->axq_depth,
  	    txq->axq_aggr_depth);
  	DPRINTF(sc, ATH_DEBUG_SW_TX | ATH_DEBUG_RESET,
  	    "%s: %s: %6D: bf=%p: tid txq_depth=%d hwq_depth=%d, bar_wait=%d, "
  	      "isfiltered=%d\n",
  	    __func__,
  	    pfx,
  	    ni->ni_macaddr,
  	    ":",
  	    bf,
  	    tid->axq_depth,
  	    tid->hwq_depth,
  	    tid->bar_wait,
  	    tid->isfiltered);
  	DPRINTF(sc, ATH_DEBUG_SW_TX | ATH_DEBUG_RESET,
  	    "%s: %s: %6D: tid %d: "
  	    "sched=%d, paused=%d, "
  	    "incomp=%d, baw_head=%d, "
  	    "baw_tail=%d txa_start=%d, ni_txseqs=%d\n",
  	     __func__,
  	     pfx,
  	     ni->ni_macaddr,
  	     ":",
  	     tid->tid,
  	     tid->sched, tid->paused,
  	     tid->incomp, tid->baw_head,
  	     tid->baw_tail, tap == NULL ? -1 : tap->txa_start,
  	     ni->ni_txseqs[tid->tid]);
  
  	/* XXX Dump the frame, see what it is? */
  	if (IFF_DUMPPKTS(sc, ATH_DEBUG_XMIT))
  		ieee80211_dump_pkt(ni->ni_ic,
  		    mtod(bf->bf_m, const uint8_t *),
  		    bf->bf_m->m_len, 0, -1);
  }
  
  /*
   * Free any packets currently pending in the software TX queue.
   *
   * This will be called when a node is being deleted.
   *
   * It can also be called on an active node during an interface
   * reset or state transition.
   *
   * (From Linux/reference):
   *
   * TODO: For frame(s) that are in the retry state, we will reuse the
   * sequence number(s) without setting the retry bit. The
   * alternative is to give up on these and BAR the receiver's window
   * forward.
   */
  static void
  ath_tx_tid_drain(struct ath_softc *sc, struct ath_node *an,
      struct ath_tid *tid, ath_bufhead *bf_cq)
  {
  	struct ath_buf *bf;
  	struct ieee80211_tx_ampdu *tap;
  	struct ieee80211_node *ni = &an->an_node;
  	int t;
  
  	tap = ath_tx_get_tx_tid(an, tid->tid);
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/* Walk the queue, free frames */
  	t = 0;
  	for (;;) {
  		bf = ATH_TID_FIRST(tid);
  		if (bf == NULL) {
  			break;
  		}
  
  		if (t == 0) {
  			ath_tx_tid_drain_print(sc, an, "norm", tid, bf);
  //			t = 1;
  		}
  
  		ATH_TID_REMOVE(tid, bf, bf_list);
  		ath_tx_tid_drain_pkt(sc, an, tid, bf_cq, bf);
  	}
  
  	/* And now, drain the filtered frame queue */
  	t = 0;
  	for (;;) {
  		bf = ATH_TID_FILT_FIRST(tid);
  		if (bf == NULL)
  			break;
  
  		if (t == 0) {
  			ath_tx_tid_drain_print(sc, an, "filt", tid, bf);
  //			t = 1;
  		}
  
  		ATH_TID_FILT_REMOVE(tid, bf, bf_list);
  		ath_tx_tid_drain_pkt(sc, an, tid, bf_cq, bf);
  	}
  
  	/*
  	 * Override the clrdmask configuration for the next frame
  	 * in case there is some future transmission, just to get
  	 * the ball rolling.
  	 *
  	 * This won't hurt things if the TID is about to be freed.
  	 */
  	ath_tx_set_clrdmask(sc, tid->an);
  
  	/*
  	 * Now that it's completed, grab the TID lock and update
  	 * the sequence number and BAW window.
  	 * Because sequence numbers have been assigned to frames
  	 * that haven't been sent yet, it's entirely possible
  	 * we'll be called with some pending frames that have not
  	 * been transmitted.
  	 *
  	 * The cleaner solution is to do the sequence number allocation
  	 * when the packet is first transmitted - and thus the "retries"
  	 * check above would be enough to update the BAW/seqno.
  	 */
  
  	/* But don't do it for non-QoS TIDs */
  	if (tap) {
  #if 1
  		DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL,
  		    "%s: %6D: node %p: TID %d: sliding BAW left edge to %d\n",
  		    __func__,
  		    ni->ni_macaddr,
  		    ":",
  		    an,
  		    tid->tid,
  		    tap->txa_start);
  #endif
  		ni->ni_txseqs[tid->tid] = tap->txa_start;
  		tid->baw_tail = tid->baw_head;
  	}
  }
  
  /*
   * Reset the TID state.  This must be only called once the node has
   * had its frames flushed from this TID, to ensure that no other
   * pause / unpause logic can kick in.
   */
  static void
  ath_tx_tid_reset(struct ath_softc *sc, struct ath_tid *tid)
  {
  
  #if 0
  	tid->bar_wait = tid->bar_tx = tid->isfiltered = 0;
  	tid->paused = tid->sched = tid->addba_tx_pending = 0;
  	tid->incomp = tid->cleanup_inprogress = 0;
  #endif
  
  	/*
  	 * If we have a bar_wait set, we need to unpause the TID
  	 * here.  Otherwise once cleanup has finished, the TID won't
  	 * have the right paused counter.
  	 *
  	 * XXX I'm not going through resume here - I don't want the
  	 * node to be rescheuled just yet.  This however should be
  	 * methodized!
  	 */
  	if (tid->bar_wait) {
  		if (tid->paused > 0) {
  			tid->paused --;
  		}
  	}
  
  	/*
  	 * XXX same with a currently filtered TID.
  	 *
  	 * Since this is being called during a flush, we assume that
  	 * the filtered frame list is actually empty.
  	 *
  	 * XXX TODO: add in a check to ensure that the filtered queue
  	 * depth is actually 0!
  	 */
  	if (tid->isfiltered) {
  		if (tid->paused > 0) {
  			tid->paused --;
  		}
  	}
  
  	/*
  	 * Clear BAR, filtered frames, scheduled and ADDBA pending.
  	 * The TID may be going through cleanup from the last association
  	 * where things in the BAW are still in the hardware queue.
  	 */
  	tid->bar_wait = 0;
  	tid->bar_tx = 0;
  	tid->isfiltered = 0;
  	tid->sched = 0;
  	tid->addba_tx_pending = 0;
  
  	/*
  	 * XXX TODO: it may just be enough to walk the HWQs and mark
  	 * frames for that node as non-aggregate; or mark the ath_node
  	 * with something that indicates that aggregation is no longer
  	 * occurring.  Then we can just toss the BAW complaints and
  	 * do a complete hard reset of state here - no pause, no
  	 * complete counter, etc.
  	 */
  
  }
  
  /*
   * Flush all software queued packets for the given node.
   *
   * This occurs when a completion handler frees the last buffer
   * for a node, and the node is thus freed. This causes the node
   * to be cleaned up, which ends up calling ath_tx_node_flush.
   */
  void
  ath_tx_node_flush(struct ath_softc *sc, struct ath_node *an)
  {
  	int tid;
  	ath_bufhead bf_cq;
  	struct ath_buf *bf;
  
  	TAILQ_INIT(&bf_cq);
  
  	ATH_KTR(sc, ATH_KTR_NODE, 1, "ath_tx_node_flush: flush node; ni=%p",
  	    &an->an_node);
  
  	ATH_TX_LOCK(sc);
  	DPRINTF(sc, ATH_DEBUG_NODE,
  	    "%s: %6D: flush; is_powersave=%d, stack_psq=%d, tim=%d, "
  	    "swq_depth=%d, clrdmask=%d, leak_count=%d\n",
  	    __func__,
  	    an->an_node.ni_macaddr,
  	    ":",
  	    an->an_is_powersave,
  	    an->an_stack_psq,
  	    an->an_tim_set,
  	    an->an_swq_depth,
  	    an->clrdmask,
  	    an->an_leak_count);
  
  	for (tid = 0; tid < IEEE80211_TID_SIZE; tid++) {
  		struct ath_tid *atid = &an->an_tid[tid];
  
  		/* Free packets */
  		ath_tx_tid_drain(sc, an, atid, &bf_cq);
  
  		/* Remove this tid from the list of active tids */
  		ath_tx_tid_unsched(sc, atid);
  
  		/* Reset the per-TID pause, BAR, etc state */
  		ath_tx_tid_reset(sc, atid);
  	}
  
  	/*
  	 * Clear global leak count
  	 */
  	an->an_leak_count = 0;
  	ATH_TX_UNLOCK(sc);
  
  	/* Handle completed frames */
  	while ((bf = TAILQ_FIRST(&bf_cq)) != NULL) {
  		TAILQ_REMOVE(&bf_cq, bf, bf_list);
  		ath_tx_default_comp(sc, bf, 0);
  	}
  }
  
  /*
   * Drain all the software TXQs currently with traffic queued.
   */
  void
  ath_tx_txq_drain(struct ath_softc *sc, struct ath_txq *txq)
  {
  	struct ath_tid *tid;
  	ath_bufhead bf_cq;
  	struct ath_buf *bf;
  
  	TAILQ_INIT(&bf_cq);
  	ATH_TX_LOCK(sc);
  
  	/*
  	 * Iterate over all active tids for the given txq,
  	 * flushing and unsched'ing them
  	 */
  	while (! TAILQ_EMPTY(&txq->axq_tidq)) {
  		tid = TAILQ_FIRST(&txq->axq_tidq);
  		ath_tx_tid_drain(sc, tid->an, tid, &bf_cq);
  		ath_tx_tid_unsched(sc, tid);
  	}
  
  	ATH_TX_UNLOCK(sc);
  
  	while ((bf = TAILQ_FIRST(&bf_cq)) != NULL) {
  		TAILQ_REMOVE(&bf_cq, bf, bf_list);
  		ath_tx_default_comp(sc, bf, 0);
  	}
  }
  
  /*
   * Handle completion of non-aggregate session frames.
   *
   * This (currently) doesn't implement software retransmission of
   * non-aggregate frames!
   *
   * Software retransmission of non-aggregate frames needs to obey
   * the strict sequence number ordering, and drop any frames that
   * will fail this.
   *
   * For now, filtered frames and frame transmission will cause
   * all kinds of issues.  So we don't support them.
   *
   * So anyone queuing frames via ath_tx_normal_xmit() or
   * ath_tx_hw_queue_norm() must override and set CLRDMASK.
   */
  void
  ath_tx_normal_comp(struct ath_softc *sc, struct ath_buf *bf, int fail)
  {
  	struct ieee80211_node *ni = bf->bf_node;
  	struct ath_node *an = ATH_NODE(ni);
  	int tid = bf->bf_state.bfs_tid;
  	struct ath_tid *atid = &an->an_tid[tid];
  	struct ath_tx_status *ts = &bf->bf_status.ds_txstat;
  
  	/* The TID state is protected behind the TXQ lock */
  	ATH_TX_LOCK(sc);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: bf=%p: fail=%d, hwq_depth now %d\n",
  	    __func__, bf, fail, atid->hwq_depth - 1);
  
  	atid->hwq_depth--;
  
  #if 0
  	/*
  	 * If the frame was filtered, stick it on the filter frame
  	 * queue and complain about it.  It shouldn't happen!
  	 */
  	if ((ts->ts_status & HAL_TXERR_FILT) ||
  	    (ts->ts_status != 0 && atid->isfiltered)) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX,
  		    "%s: isfiltered=%d, ts_status=%d: huh?\n",
  		    __func__,
  		    atid->isfiltered,
  		    ts->ts_status);
  		ath_tx_tid_filt_comp_buf(sc, atid, bf);
  	}
  #endif
  	if (atid->isfiltered)
  		DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: filtered?!\n", __func__);
  	if (atid->hwq_depth < 0)
  		DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: hwq_depth < 0: %d\n",
  		    __func__, atid->hwq_depth);
  
  	/* If the TID is being cleaned up, track things */
  	/* XXX refactor! */
  	if (atid->cleanup_inprogress) {
  		atid->incomp--;
  		if (atid->incomp == 0) {
  			DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL,
  			    "%s: TID %d: cleaned up! resume!\n",
  			    __func__, tid);
  			atid->cleanup_inprogress = 0;
  			ath_tx_tid_resume(sc, atid);
  		}
  	}
  
  	/*
  	 * If the queue is filtered, potentially mark it as complete
  	 * and reschedule it as needed.
  	 *
  	 * This is required as there may be a subsequent TX descriptor
  	 * for this end-node that has CLRDMASK set, so it's quite possible
  	 * that a filtered frame will be followed by a non-filtered
  	 * (complete or otherwise) frame.
  	 *
  	 * XXX should we do this before we complete the frame?
  	 */
  	if (atid->isfiltered)
  		ath_tx_tid_filt_comp_complete(sc, atid);
  	ATH_TX_UNLOCK(sc);
  
  	/*
  	 * punt to rate control if we're not being cleaned up
  	 * during a hw queue drain and the frame wanted an ACK.
  	 */
  	if (fail == 0 && ((bf->bf_state.bfs_txflags & HAL_TXDESC_NOACK) == 0))
  		ath_tx_update_ratectrl(sc, ni, bf->bf_state.bfs_rc,
  		    ts, bf->bf_state.bfs_pktlen,
  		    1, (ts->ts_status == 0) ? 0 : 1);
  
  	ath_tx_default_comp(sc, bf, fail);
  }
  
  /*
   * Handle cleanup of aggregate session packets that aren't
   * an A-MPDU.
   *
   * There's no need to update the BAW here - the session is being
   * torn down.
   */
  static void
  ath_tx_comp_cleanup_unaggr(struct ath_softc *sc, struct ath_buf *bf)
  {
  	struct ieee80211_node *ni = bf->bf_node;
  	struct ath_node *an = ATH_NODE(ni);
  	int tid = bf->bf_state.bfs_tid;
  	struct ath_tid *atid = &an->an_tid[tid];
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL, "%s: TID %d: incomp=%d\n",
  	    __func__, tid, atid->incomp);
  
  	ATH_TX_LOCK(sc);
  	atid->incomp--;
  
  	/* XXX refactor! */
  	if (bf->bf_state.bfs_dobaw) {
  		ath_tx_update_baw(sc, an, atid, bf);
  		if (!bf->bf_state.bfs_addedbaw)
  			DPRINTF(sc, ATH_DEBUG_SW_TX,
  			    "%s: wasn't added: seqno %d\n",
  			    __func__, SEQNO(bf->bf_state.bfs_seqno));
  	}
  
  	if (atid->incomp == 0) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL,
  		    "%s: TID %d: cleaned up! resume!\n",
  		    __func__, tid);
  		atid->cleanup_inprogress = 0;
  		ath_tx_tid_resume(sc, atid);
  	}
  	ATH_TX_UNLOCK(sc);
  
  	ath_tx_default_comp(sc, bf, 0);
  }
  
  
  /*
   * This as it currently stands is a bit dumb.  Ideally we'd just
   * fail the frame the normal way and have it permanently fail
   * via the normal aggregate completion path.
   */
  static void
  ath_tx_tid_cleanup_frame(struct ath_softc *sc, struct ath_node *an,
      int tid, struct ath_buf *bf_head, ath_bufhead *bf_cq)
  {
  	struct ath_tid *atid = &an->an_tid[tid];
  	struct ath_buf *bf, *bf_next;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/*
  	 * Remove this frame from the queue.
  	 */
  	ATH_TID_REMOVE(atid, bf_head, bf_list);
  
  	/*
  	 * Loop over all the frames in the aggregate.
  	 */
  	bf = bf_head;
  	while (bf != NULL) {
  		bf_next = bf->bf_next;	/* next aggregate frame, or NULL */
  
  		/*
  		 * If it's been added to the BAW we need to kick
  		 * it out of the BAW before we continue.
  		 *
  		 * XXX if it's an aggregate, assert that it's in the
  		 * BAW - we shouldn't have it be in an aggregate
  		 * otherwise!
  		 */
  		if (bf->bf_state.bfs_addedbaw) {
  			ath_tx_update_baw(sc, an, atid, bf);
  			bf->bf_state.bfs_dobaw = 0;
  		}
  
  		/*
  		 * Give it the default completion handler.
  		 */
  		bf->bf_comp = ath_tx_normal_comp;
  		bf->bf_next = NULL;
  
  		/*
  		 * Add it to the list to free.
  		 */
  		TAILQ_INSERT_TAIL(bf_cq, bf, bf_list);
  
  		/*
  		 * Now advance to the next frame in the aggregate.
  		 */
  		bf = bf_next;
  	}
  }
  
  /*
   * Performs transmit side cleanup when TID changes from aggregated to
   * unaggregated and during reassociation.
   *
   * For now, this just tosses everything from the TID software queue
   * whether or not it has been retried and marks the TID as
   * pending completion if there's anything for this TID queued to
   * the hardware.
   *
   * The caller is responsible for pausing the TID and unpausing the
   * TID if no cleanup was required. Otherwise the cleanup path will
   * unpause the TID once the last hardware queued frame is completed.
   */
  static void
  ath_tx_tid_cleanup(struct ath_softc *sc, struct ath_node *an, int tid,
      ath_bufhead *bf_cq)
  {
  	struct ath_tid *atid = &an->an_tid[tid];
  	struct ath_buf *bf, *bf_next;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  	    "%s: TID %d: called; inprogress=%d\n", __func__, tid,
  	    atid->cleanup_inprogress);
  
  	/*
  	 * Move the filtered frames to the TX queue, before
  	 * we run off and discard/process things.
  	 */
  
  	/* XXX this is really quite inefficient */
  	while ((bf = ATH_TID_FILT_LAST(atid, ath_bufhead_s)) != NULL) {
  		ATH_TID_FILT_REMOVE(atid, bf, bf_list);
  		ATH_TID_INSERT_HEAD(atid, bf, bf_list);
  	}
  
  	/*
  	 * Update the frames in the software TX queue:
  	 *
  	 * + Discard retry frames in the queue
  	 * + Fix the completion function to be non-aggregate
  	 */
  	bf = ATH_TID_FIRST(atid);
  	while (bf) {
  		/*
  		 * Grab the next frame in the list, we may
  		 * be fiddling with the list.
  		 */
  		bf_next = TAILQ_NEXT(bf, bf_list);
  
  		/*
  		 * Free the frame and all subframes.
  		 */
  		ath_tx_tid_cleanup_frame(sc, an, tid, bf, bf_cq);
  
  		/*
  		 * Next frame!
  		 */
  		bf = bf_next;
  	}
  
  	/*
  	 * If there's anything in the hardware queue we wait
  	 * for the TID HWQ to empty.
  	 */
  	if (atid->hwq_depth > 0) {
  		/*
  		 * XXX how about we kill atid->incomp, and instead
  		 * replace it with a macro that checks that atid->hwq_depth
  		 * is 0?
  		 */
  		atid->incomp = atid->hwq_depth;
  		atid->cleanup_inprogress = 1;
  	}
  
  	if (atid->cleanup_inprogress)
  		DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL,
  		    "%s: TID %d: cleanup needed: %d packets\n",
  		    __func__, tid, atid->incomp);
  
  	/* Owner now must free completed frames */
  }
  
  static struct ath_buf *
  ath_tx_retry_clone(struct ath_softc *sc, struct ath_node *an,
      struct ath_tid *tid, struct ath_buf *bf)
  {
  	struct ath_buf *nbf;
  	int error;
  
  	/*
  	 * Clone the buffer.  This will handle the dma unmap and
  	 * copy the node reference to the new buffer.  If this
  	 * works out, 'bf' will have no DMA mapping, no mbuf
  	 * pointer and no node reference.
  	 */
  	nbf = ath_buf_clone(sc, bf);
  
  #if 0
  	DPRINTF(sc, ATH_DEBUG_XMIT, "%s: ATH_BUF_BUSY; cloning\n",
  	    __func__);
  #endif
  
  	if (nbf == NULL) {
  		/* Failed to clone */
  		DPRINTF(sc, ATH_DEBUG_XMIT,
  		    "%s: failed to clone a busy buffer\n",
  		    __func__);
  		return NULL;
  	}
  
  	/* Setup the dma for the new buffer */
  	error = ath_tx_dmasetup(sc, nbf, nbf->bf_m);
  	if (error != 0) {
  		DPRINTF(sc, ATH_DEBUG_XMIT,
  		    "%s: failed to setup dma for clone\n",
  		    __func__);
  		/*
  		 * Put this at the head of the list, not tail;
  		 * that way it doesn't interfere with the
  		 * busy buffer logic (which uses the tail of
  		 * the list.)
  		 */
  		ATH_TXBUF_LOCK(sc);
  		ath_returnbuf_head(sc, nbf);
  		ATH_TXBUF_UNLOCK(sc);
  		return NULL;
  	}
  
  	/* Update BAW if required, before we free the original buf */
  	if (bf->bf_state.bfs_dobaw)
  		ath_tx_switch_baw_buf(sc, an, tid, bf, nbf);
  
  	/* Free original buffer; return new buffer */
  	ath_freebuf(sc, bf);
  
  	return nbf;
  }
  
  /*
   * Handle retrying an unaggregate frame in an aggregate
   * session.
   *
   * If too many retries occur, pause the TID, wait for
   * any further retransmits (as there's no reason why
   * non-aggregate frames in an aggregate session are
   * transmitted in-order; they just have to be in-BAW)
   * and then queue a BAR.
   */
  static void
  ath_tx_aggr_retry_unaggr(struct ath_softc *sc, struct ath_buf *bf)
  {
  	struct ieee80211_node *ni = bf->bf_node;
  	struct ath_node *an = ATH_NODE(ni);
  	int tid = bf->bf_state.bfs_tid;
  	struct ath_tid *atid = &an->an_tid[tid];
  	struct ieee80211_tx_ampdu *tap;
  
  	ATH_TX_LOCK(sc);
  
  	tap = ath_tx_get_tx_tid(an, tid);
  
  	/*
  	 * If the buffer is marked as busy, we can't directly
  	 * reuse it. Instead, try to clone the buffer.
  	 * If the clone is successful, recycle the old buffer.
  	 * If the clone is unsuccessful, set bfs_retries to max
  	 * to force the next bit of code to free the buffer
  	 * for us.
  	 */
  	if ((bf->bf_state.bfs_retries < SWMAX_RETRIES) &&
  	    (bf->bf_flags & ATH_BUF_BUSY)) {
  		struct ath_buf *nbf;
  		nbf = ath_tx_retry_clone(sc, an, atid, bf);
  		if (nbf)
  			/* bf has been freed at this point */
  			bf = nbf;
  		else
  			bf->bf_state.bfs_retries = SWMAX_RETRIES + 1;
  	}
  
  	if (bf->bf_state.bfs_retries >= SWMAX_RETRIES) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_RETRIES,
  		    "%s: exceeded retries; seqno %d\n",
  		    __func__, SEQNO(bf->bf_state.bfs_seqno));
  		sc->sc_stats.ast_tx_swretrymax++;
  
  		/* Update BAW anyway */
  		if (bf->bf_state.bfs_dobaw) {
  			ath_tx_update_baw(sc, an, atid, bf);
  			if (! bf->bf_state.bfs_addedbaw)
  				DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  				    "%s: wasn't added: seqno %d\n",
  				    __func__, SEQNO(bf->bf_state.bfs_seqno));
  		}
  		bf->bf_state.bfs_dobaw = 0;
  
  		/* Suspend the TX queue and get ready to send the BAR */
  		ath_tx_tid_bar_suspend(sc, atid);
  
  		/* Send the BAR if there are no other frames waiting */
  		if (ath_tx_tid_bar_tx_ready(sc, atid))
  			ath_tx_tid_bar_tx(sc, atid);
  
  		ATH_TX_UNLOCK(sc);
  
  		/* Free buffer, bf is free after this call */
  		ath_tx_default_comp(sc, bf, 0);
  		return;
  	}
  
  	/*
  	 * This increments the retry counter as well as
  	 * sets the retry flag in the ath_buf and packet
  	 * body.
  	 */
  	ath_tx_set_retry(sc, bf);
  	sc->sc_stats.ast_tx_swretries++;
  
  	/*
  	 * Insert this at the head of the queue, so it's
  	 * retried before any current/subsequent frames.
  	 */
  	ATH_TID_INSERT_HEAD(atid, bf, bf_list);
  	ath_tx_tid_sched(sc, atid);
  	/* Send the BAR if there are no other frames waiting */
  	if (ath_tx_tid_bar_tx_ready(sc, atid))
  		ath_tx_tid_bar_tx(sc, atid);
  
  	ATH_TX_UNLOCK(sc);
  }
  
  /*
   * Common code for aggregate excessive retry/subframe retry.
   * If retrying, queues buffers to bf_q. If not, frees the
   * buffers.
   *
   * XXX should unify this with ath_tx_aggr_retry_unaggr()
   */
  static int
  ath_tx_retry_subframe(struct ath_softc *sc, struct ath_buf *bf,
      ath_bufhead *bf_q)
  {
  	struct ieee80211_node *ni = bf->bf_node;
  	struct ath_node *an = ATH_NODE(ni);
  	int tid = bf->bf_state.bfs_tid;
  	struct ath_tid *atid = &an->an_tid[tid];
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/* XXX clr11naggr should be done for all subframes */
  	ath_hal_clr11n_aggr(sc->sc_ah, bf->bf_desc);
  	ath_hal_set11nburstduration(sc->sc_ah, bf->bf_desc, 0);
  
  	/* ath_hal_set11n_virtualmorefrag(sc->sc_ah, bf->bf_desc, 0); */
  
  	/*
  	 * If the buffer is marked as busy, we can't directly
  	 * reuse it. Instead, try to clone the buffer.
  	 * If the clone is successful, recycle the old buffer.
  	 * If the clone is unsuccessful, set bfs_retries to max
  	 * to force the next bit of code to free the buffer
  	 * for us.
  	 */
  	if ((bf->bf_state.bfs_retries < SWMAX_RETRIES) &&
  	    (bf->bf_flags & ATH_BUF_BUSY)) {
  		struct ath_buf *nbf;
  		nbf = ath_tx_retry_clone(sc, an, atid, bf);
  		if (nbf)
  			/* bf has been freed at this point */
  			bf = nbf;
  		else
  			bf->bf_state.bfs_retries = SWMAX_RETRIES + 1;
  	}
  
  	if (bf->bf_state.bfs_retries >= SWMAX_RETRIES) {
  		sc->sc_stats.ast_tx_swretrymax++;
  		DPRINTF(sc, ATH_DEBUG_SW_TX_RETRIES,
  		    "%s: max retries: seqno %d\n",
  		    __func__, SEQNO(bf->bf_state.bfs_seqno));
  		ath_tx_update_baw(sc, an, atid, bf);
  		if (!bf->bf_state.bfs_addedbaw)
  			DPRINTF(sc, ATH_DEBUG_SW_TX_BAW,
  			    "%s: wasn't added: seqno %d\n",
  			    __func__, SEQNO(bf->bf_state.bfs_seqno));
  		bf->bf_state.bfs_dobaw = 0;
  		return 1;
  	}
  
  	ath_tx_set_retry(sc, bf);
  	sc->sc_stats.ast_tx_swretries++;
  	bf->bf_next = NULL;		/* Just to make sure */
  
  	/* Clear the aggregate state */
  	bf->bf_state.bfs_aggr = 0;
  	bf->bf_state.bfs_ndelim = 0;	/* ??? needed? */
  	bf->bf_state.bfs_nframes = 1;
  
  	TAILQ_INSERT_TAIL(bf_q, bf, bf_list);
  	return 0;
  }
  
  /*
   * error pkt completion for an aggregate destination
   */
  static void
  ath_tx_comp_aggr_error(struct ath_softc *sc, struct ath_buf *bf_first,
      struct ath_tid *tid)
  {
  	struct ieee80211_node *ni = bf_first->bf_node;
  	struct ath_node *an = ATH_NODE(ni);
  	struct ath_buf *bf_next, *bf;
  	ath_bufhead bf_q;
  	int drops = 0;
  	struct ieee80211_tx_ampdu *tap;
  	ath_bufhead bf_cq;
  
  	TAILQ_INIT(&bf_q);
  	TAILQ_INIT(&bf_cq);
  
  	/*
  	 * Update rate control - all frames have failed.
  	 *
  	 * XXX use the length in the first frame in the series;
  	 * XXX just so things are consistent for now.
  	 */
  	ath_tx_update_ratectrl(sc, ni, bf_first->bf_state.bfs_rc,
  	    &bf_first->bf_status.ds_txstat,
  	    bf_first->bf_state.bfs_pktlen,
  	    bf_first->bf_state.bfs_nframes, bf_first->bf_state.bfs_nframes);
  
  	ATH_TX_LOCK(sc);
  	tap = ath_tx_get_tx_tid(an, tid->tid);
  	sc->sc_stats.ast_tx_aggr_failall++;
  
  	/* Retry all subframes */
  	bf = bf_first;
  	while (bf) {
  		bf_next = bf->bf_next;
  		bf->bf_next = NULL;	/* Remove it from the aggr list */
  		sc->sc_stats.ast_tx_aggr_fail++;
  		if (ath_tx_retry_subframe(sc, bf, &bf_q)) {
  			drops++;
  			bf->bf_next = NULL;
  			TAILQ_INSERT_TAIL(&bf_cq, bf, bf_list);
  		}
  		bf = bf_next;
  	}
  
  	/* Prepend all frames to the beginning of the queue */
  	while ((bf = TAILQ_LAST(&bf_q, ath_bufhead_s)) != NULL) {
  		TAILQ_REMOVE(&bf_q, bf, bf_list);
  		ATH_TID_INSERT_HEAD(tid, bf, bf_list);
  	}
  
  	/*
  	 * Schedule the TID to be re-tried.
  	 */
  	ath_tx_tid_sched(sc, tid);
  
  	/*
  	 * send bar if we dropped any frames
  	 *
  	 * Keep the txq lock held for now, as we need to ensure
  	 * that ni_txseqs[] is consistent (as it's being updated
  	 * in the ifnet TX context or raw TX context.)
  	 */
  	if (drops) {
  		/* Suspend the TX queue and get ready to send the BAR */
  		ath_tx_tid_bar_suspend(sc, tid);
  	}
  
  	/*
  	 * Send BAR if required
  	 */
  	if (ath_tx_tid_bar_tx_ready(sc, tid))
  		ath_tx_tid_bar_tx(sc, tid);
  
  	ATH_TX_UNLOCK(sc);
  
  	/* Complete frames which errored out */
  	while ((bf = TAILQ_FIRST(&bf_cq)) != NULL) {
  		TAILQ_REMOVE(&bf_cq, bf, bf_list);
  		ath_tx_default_comp(sc, bf, 0);
  	}
  }
  
  /*
   * Handle clean-up of packets from an aggregate list.
   *
   * There's no need to update the BAW here - the session is being
   * torn down.
   */
  static void
  ath_tx_comp_cleanup_aggr(struct ath_softc *sc, struct ath_buf *bf_first)
  {
  	struct ath_buf *bf, *bf_next;
  	struct ieee80211_node *ni = bf_first->bf_node;
  	struct ath_node *an = ATH_NODE(ni);
  	int tid = bf_first->bf_state.bfs_tid;
  	struct ath_tid *atid = &an->an_tid[tid];
  
  	ATH_TX_LOCK(sc);
  
  	/* update incomp */
  	atid->incomp--;
  
  	/* Update the BAW */
  	bf = bf_first;
  	while (bf) {
  		/* XXX refactor! */
  		if (bf->bf_state.bfs_dobaw) {
  			ath_tx_update_baw(sc, an, atid, bf);
  			if (!bf->bf_state.bfs_addedbaw)
  				DPRINTF(sc, ATH_DEBUG_SW_TX,
  				    "%s: wasn't added: seqno %d\n",
  				    __func__, SEQNO(bf->bf_state.bfs_seqno));
  		}
  		bf = bf->bf_next;
  	}
  
  	if (atid->incomp == 0) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL,
  		    "%s: TID %d: cleaned up! resume!\n",
  		    __func__, tid);
  		atid->cleanup_inprogress = 0;
  		ath_tx_tid_resume(sc, atid);
  	}
  
  	/* Send BAR if required */
  	/* XXX why would we send a BAR when transitioning to non-aggregation? */
  	/*
  	 * XXX TODO: we should likely just tear down the BAR state here,
  	 * rather than sending a BAR.
  	 */
  	if (ath_tx_tid_bar_tx_ready(sc, atid))
  		ath_tx_tid_bar_tx(sc, atid);
  
  	ATH_TX_UNLOCK(sc);
  
  	/* Handle frame completion as individual frames */
  	bf = bf_first;
  	while (bf) {
  		bf_next = bf->bf_next;
  		bf->bf_next = NULL;
  		ath_tx_default_comp(sc, bf, 1);
  		bf = bf_next;
  	}
  }
  
  /*
   * Handle completion of an set of aggregate frames.
   *
   * Note: the completion handler is the last descriptor in the aggregate,
   * not the last descriptor in the first frame.
   */
  static void
  ath_tx_aggr_comp_aggr(struct ath_softc *sc, struct ath_buf *bf_first,
      int fail)
  {
  	//struct ath_desc *ds = bf->bf_lastds;
  	struct ieee80211_node *ni = bf_first->bf_node;
  	struct ath_node *an = ATH_NODE(ni);
  	int tid = bf_first->bf_state.bfs_tid;
  	struct ath_tid *atid = &an->an_tid[tid];
  	struct ath_tx_status ts;
  	struct ieee80211_tx_ampdu *tap;
  	ath_bufhead bf_q;
  	ath_bufhead bf_cq;
  	int seq_st, tx_ok;
  	int hasba, isaggr;
  	uint32_t ba[2];
  	struct ath_buf *bf, *bf_next;
  	int ba_index;
  	int drops = 0;
  	int nframes = 0, nbad = 0, nf;
  	int pktlen;
  	/* XXX there's too much on the stack? */
  	struct ath_rc_series rc[ATH_RC_NUM];
  	int txseq;
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR, "%s: called; hwq_depth=%d\n",
  	    __func__, atid->hwq_depth);
  
  	/*
  	 * Take a copy; this may be needed -after- bf_first
  	 * has been completed and freed.
  	 */
  	ts = bf_first->bf_status.ds_txstat;
  
  	TAILQ_INIT(&bf_q);
  	TAILQ_INIT(&bf_cq);
  
  	/* The TID state is kept behind the TXQ lock */
  	ATH_TX_LOCK(sc);
  
  	atid->hwq_depth--;
  	if (atid->hwq_depth < 0)
  		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR, "%s: hwq_depth < 0: %d\n",
  		    __func__, atid->hwq_depth);
  
  	/*
  	 * If the TID is filtered, handle completing the filter
  	 * transition before potentially kicking it to the cleanup
  	 * function.
  	 *
  	 * XXX this is duplicate work, ew.
  	 */
  	if (atid->isfiltered)
  		ath_tx_tid_filt_comp_complete(sc, atid);
  
  	/*
  	 * Punt cleanup to the relevant function, not our problem now
  	 */
  	if (atid->cleanup_inprogress) {
  		if (atid->isfiltered)
  			DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  			    "%s: isfiltered=1, normal_comp?\n",
  			    __func__);
  		ATH_TX_UNLOCK(sc);
  		ath_tx_comp_cleanup_aggr(sc, bf_first);
  		return;
  	}
  
  	/*
  	 * If the frame is filtered, transition to filtered frame
  	 * mode and add this to the filtered frame list.
  	 *
  	 * XXX TODO: figure out how this interoperates with
  	 * BAR, pause and cleanup states.
  	 */
  	if ((ts.ts_status & HAL_TXERR_FILT) ||
  	    (ts.ts_status != 0 && atid->isfiltered)) {
  		if (fail != 0)
  			DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  			    "%s: isfiltered=1, fail=%d\n", __func__, fail);
  		ath_tx_tid_filt_comp_aggr(sc, atid, bf_first, &bf_cq);
  
  		/* Remove from BAW */
  		TAILQ_FOREACH_SAFE(bf, &bf_cq, bf_list, bf_next) {
  			if (bf->bf_state.bfs_addedbaw)
  				drops++;
  			if (bf->bf_state.bfs_dobaw) {
  				ath_tx_update_baw(sc, an, atid, bf);
  				if (!bf->bf_state.bfs_addedbaw)
  					DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  					    "%s: wasn't added: seqno %d\n",
  					    __func__,
  					    SEQNO(bf->bf_state.bfs_seqno));
  			}
  			bf->bf_state.bfs_dobaw = 0;
  		}
  		/*
  		 * If any intermediate frames in the BAW were dropped when
  		 * handling filtering things, send a BAR.
  		 */
  		if (drops)
  			ath_tx_tid_bar_suspend(sc, atid);
  
  		/*
  		 * Finish up by sending a BAR if required and freeing
  		 * the frames outside of the TX lock.
  		 */
  		goto finish_send_bar;
  	}
  
  	/*
  	 * XXX for now, use the first frame in the aggregate for
  	 * XXX rate control completion; it's at least consistent.
  	 */
  	pktlen = bf_first->bf_state.bfs_pktlen;
  
  	/*
  	 * Handle errors first!
  	 *
  	 * Here, handle _any_ error as a "exceeded retries" error.
  	 * Later on (when filtered frames are to be specially handled)
  	 * it'll have to be expanded.
  	 */
  #if 0
  	if (ts.ts_status & HAL_TXERR_XRETRY) {
  #endif
  	if (ts.ts_status != 0) {
  		ATH_TX_UNLOCK(sc);
  		ath_tx_comp_aggr_error(sc, bf_first, atid);
  		return;
  	}
  
  	tap = ath_tx_get_tx_tid(an, tid);
  
  	/*
  	 * extract starting sequence and block-ack bitmap
  	 */
  	/* XXX endian-ness of seq_st, ba? */
  	seq_st = ts.ts_seqnum;
  	hasba = !! (ts.ts_flags & HAL_TX_BA);
  	tx_ok = (ts.ts_status == 0);
  	isaggr = bf_first->bf_state.bfs_aggr;
  	ba[0] = ts.ts_ba_low;
  	ba[1] = ts.ts_ba_high;
  
  	/*
  	 * Copy the TX completion status and the rate control
  	 * series from the first descriptor, as it may be freed
  	 * before the rate control code can get its grubby fingers
  	 * into things.
  	 */
  	memcpy(rc, bf_first->bf_state.bfs_rc, sizeof(rc));
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  	    "%s: txa_start=%d, tx_ok=%d, status=%.8x, flags=%.8x, "
  	    "isaggr=%d, seq_st=%d, hasba=%d, ba=%.8x, %.8x\n",
  	    __func__, tap->txa_start, tx_ok, ts.ts_status, ts.ts_flags,
  	    isaggr, seq_st, hasba, ba[0], ba[1]);
  
  	/*
  	 * The reference driver doesn't do this; it simply ignores
  	 * this check in its entirety.
  	 *
  	 * I've seen this occur when using iperf to send traffic
  	 * out tid 1 - the aggregate frames are all marked as TID 1,
  	 * but the TXSTATUS has TID=0.  So, let's just ignore this
  	 * check.
  	 */
  #if 0
  	/* Occasionally, the MAC sends a tx status for the wrong TID. */
  	if (tid != ts.ts_tid) {
  		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR, "%s: tid %d != hw tid %d\n",
  		    __func__, tid, ts.ts_tid);
  		tx_ok = 0;
  	}
  #endif
  
  	/* AR5416 BA bug; this requires an interface reset */
  	if (isaggr && tx_ok && (! hasba)) {
  		device_printf(sc->sc_dev,
  		    "%s: AR5416 bug: hasba=%d; txok=%d, isaggr=%d, "
  		    "seq_st=%d\n",
  		    __func__, hasba, tx_ok, isaggr, seq_st);
  		/* XXX TODO: schedule an interface reset */
  #ifdef ATH_DEBUG
  		ath_printtxbuf(sc, bf_first,
  		    sc->sc_ac2q[atid->ac]->axq_qnum, 0, 0);
  #endif
  	}
  
  	/*
  	 * Walk the list of frames, figure out which ones were correctly
  	 * sent and which weren't.
  	 */
  	bf = bf_first;
  	nf = bf_first->bf_state.bfs_nframes;
  
  	/* bf_first is going to be invalid once this list is walked */
  	bf_first = NULL;
  
  	/*
  	 * Walk the list of completed frames and determine
  	 * which need to be completed and which need to be
  	 * retransmitted.
  	 *
  	 * For completed frames, the completion functions need
  	 * to be called at the end of this function as the last
  	 * node reference may free the node.
  	 *
  	 * Finally, since the TXQ lock can't be held during the
  	 * completion callback (to avoid lock recursion),
  	 * the completion calls have to be done outside of the
  	 * lock.
  	 */
  	while (bf) {
  		nframes++;
  		ba_index = ATH_BA_INDEX(seq_st,
  		    SEQNO(bf->bf_state.bfs_seqno));
  		bf_next = bf->bf_next;
  		bf->bf_next = NULL;	/* Remove it from the aggr list */
  
  		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  		    "%s: checking bf=%p seqno=%d; ack=%d\n",
  		    __func__, bf, SEQNO(bf->bf_state.bfs_seqno),
  		    ATH_BA_ISSET(ba, ba_index));
  
  		if (tx_ok && ATH_BA_ISSET(ba, ba_index)) {
  			sc->sc_stats.ast_tx_aggr_ok++;
  			ath_tx_update_baw(sc, an, atid, bf);
  			bf->bf_state.bfs_dobaw = 0;
  			if (!bf->bf_state.bfs_addedbaw)
  				DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  				    "%s: wasn't added: seqno %d\n",
  				    __func__, SEQNO(bf->bf_state.bfs_seqno));
  			bf->bf_next = NULL;
  			TAILQ_INSERT_TAIL(&bf_cq, bf, bf_list);
  		} else {
  			sc->sc_stats.ast_tx_aggr_fail++;
  			if (ath_tx_retry_subframe(sc, bf, &bf_q)) {
  				drops++;
  				bf->bf_next = NULL;
  				TAILQ_INSERT_TAIL(&bf_cq, bf, bf_list);
  			}
  			nbad++;
  		}
  		bf = bf_next;
  	}
  
  	/*
  	 * Now that the BAW updates have been done, unlock
  	 *
  	 * txseq is grabbed before the lock is released so we
  	 * have a consistent view of what -was- in the BAW.
  	 * Anything after this point will not yet have been
  	 * TXed.
  	 */
  	txseq = tap->txa_start;
  	ATH_TX_UNLOCK(sc);
  
  	if (nframes != nf)
  		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  		    "%s: num frames seen=%d; bf nframes=%d\n",
  		    __func__, nframes, nf);
  
  	/*
  	 * Now we know how many frames were bad, call the rate
  	 * control code.
  	 */
  	if (fail == 0)
  		ath_tx_update_ratectrl(sc, ni, rc, &ts, pktlen, nframes,
  		    nbad);
  
  	/*
  	 * send bar if we dropped any frames
  	 */
  	if (drops) {
  		/* Suspend the TX queue and get ready to send the BAR */
  		ATH_TX_LOCK(sc);
  		ath_tx_tid_bar_suspend(sc, atid);
  		ATH_TX_UNLOCK(sc);
  	}
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  	    "%s: txa_start now %d\n", __func__, tap->txa_start);
  
  	ATH_TX_LOCK(sc);
  
  	/* Prepend all frames to the beginning of the queue */
  	while ((bf = TAILQ_LAST(&bf_q, ath_bufhead_s)) != NULL) {
  		TAILQ_REMOVE(&bf_q, bf, bf_list);
  		ATH_TID_INSERT_HEAD(atid, bf, bf_list);
  	}
  
  	/*
  	 * Reschedule to grab some further frames.
  	 */
  	ath_tx_tid_sched(sc, atid);
  
  	/*
  	 * If the queue is filtered, re-schedule as required.
  	 *
  	 * This is required as there may be a subsequent TX descriptor
  	 * for this end-node that has CLRDMASK set, so it's quite possible
  	 * that a filtered frame will be followed by a non-filtered
  	 * (complete or otherwise) frame.
  	 *
  	 * XXX should we do this before we complete the frame?
  	 */
  	if (atid->isfiltered)
  		ath_tx_tid_filt_comp_complete(sc, atid);
  
  finish_send_bar:
  
  	/*
  	 * Send BAR if required
  	 */
  	if (ath_tx_tid_bar_tx_ready(sc, atid))
  		ath_tx_tid_bar_tx(sc, atid);
  
  	ATH_TX_UNLOCK(sc);
  
  	/* Do deferred completion */
  	while ((bf = TAILQ_FIRST(&bf_cq)) != NULL) {
  		TAILQ_REMOVE(&bf_cq, bf, bf_list);
  		ath_tx_default_comp(sc, bf, 0);
  	}
  }
  
  /*
   * Handle completion of unaggregated frames in an ADDBA
   * session.
   *
   * Fail is set to 1 if the entry is being freed via a call to
   * ath_tx_draintxq().
   */
  static void
  ath_tx_aggr_comp_unaggr(struct ath_softc *sc, struct ath_buf *bf, int fail)
  {
  	struct ieee80211_node *ni = bf->bf_node;
  	struct ath_node *an = ATH_NODE(ni);
  	int tid = bf->bf_state.bfs_tid;
  	struct ath_tid *atid = &an->an_tid[tid];
  	struct ath_tx_status ts;
  	int drops = 0;
  
  	/*
  	 * Take a copy of this; filtering/cloning the frame may free the
  	 * bf pointer.
  	 */
  	ts = bf->bf_status.ds_txstat;
  
  	/*
  	 * Update rate control status here, before we possibly
  	 * punt to retry or cleanup.
  	 *
  	 * Do it outside of the TXQ lock.
  	 */
  	if (fail == 0 && ((bf->bf_state.bfs_txflags & HAL_TXDESC_NOACK) == 0))
  		ath_tx_update_ratectrl(sc, ni, bf->bf_state.bfs_rc,
  		    &bf->bf_status.ds_txstat,
  		    bf->bf_state.bfs_pktlen,
  		    1, (ts.ts_status == 0) ? 0 : 1);
  
  	/*
  	 * This is called early so atid->hwq_depth can be tracked.
  	 * This unfortunately means that it's released and regrabbed
  	 * during retry and cleanup. That's rather inefficient.
  	 */
  	ATH_TX_LOCK(sc);
  
  	if (tid == IEEE80211_NONQOS_TID)
  		DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: TID=16!\n", __func__);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX,
  	    "%s: bf=%p: tid=%d, hwq_depth=%d, seqno=%d\n",
  	    __func__, bf, bf->bf_state.bfs_tid, atid->hwq_depth,
  	    SEQNO(bf->bf_state.bfs_seqno));
  
  	atid->hwq_depth--;
  	if (atid->hwq_depth < 0)
  		DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: hwq_depth < 0: %d\n",
  		    __func__, atid->hwq_depth);
  
  	/*
  	 * If the TID is filtered, handle completing the filter
  	 * transition before potentially kicking it to the cleanup
  	 * function.
  	 */
  	if (atid->isfiltered)
  		ath_tx_tid_filt_comp_complete(sc, atid);
  
  	/*
  	 * If a cleanup is in progress, punt to comp_cleanup;
  	 * rather than handling it here. It's thus their
  	 * responsibility to clean up, call the completion
  	 * function in net80211, etc.
  	 */
  	if (atid->cleanup_inprogress) {
  		if (atid->isfiltered)
  			DPRINTF(sc, ATH_DEBUG_SW_TX,
  			    "%s: isfiltered=1, normal_comp?\n",
  			    __func__);
  		ATH_TX_UNLOCK(sc);
  		DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: cleanup_unaggr\n",
  		    __func__);
  		ath_tx_comp_cleanup_unaggr(sc, bf);
  		return;
  	}
  
  	/*
  	 * XXX TODO: how does cleanup, BAR and filtered frame handling
  	 * overlap?
  	 *
  	 * If the frame is filtered OR if it's any failure but
  	 * the TID is filtered, the frame must be added to the
  	 * filtered frame list.
  	 *
  	 * However - a busy buffer can't be added to the filtered
  	 * list as it will end up being recycled without having
  	 * been made available for the hardware.
  	 */
  	if ((ts.ts_status & HAL_TXERR_FILT) ||
  	    (ts.ts_status != 0 && atid->isfiltered)) {
  		int freeframe;
  
  		if (fail != 0)
  			DPRINTF(sc, ATH_DEBUG_SW_TX,
  			    "%s: isfiltered=1, fail=%d\n",
  			    __func__, fail);
  		freeframe = ath_tx_tid_filt_comp_single(sc, atid, bf);
  		/*
  		 * If freeframe=0 then bf is no longer ours; don't
  		 * touch it.
  		 */
  		if (freeframe) {
  			/* Remove from BAW */
  			if (bf->bf_state.bfs_addedbaw)
  				drops++;
  			if (bf->bf_state.bfs_dobaw) {
  				ath_tx_update_baw(sc, an, atid, bf);
  				if (!bf->bf_state.bfs_addedbaw)
  					DPRINTF(sc, ATH_DEBUG_SW_TX,
  					    "%s: wasn't added: seqno %d\n",
  					    __func__, SEQNO(bf->bf_state.bfs_seqno));
  			}
  			bf->bf_state.bfs_dobaw = 0;
  		}
  
  		/*
  		 * If the frame couldn't be filtered, treat it as a drop and
  		 * prepare to send a BAR.
  		 */
  		if (freeframe && drops)
  			ath_tx_tid_bar_suspend(sc, atid);
  
  		/*
  		 * Send BAR if required
  		 */
  		if (ath_tx_tid_bar_tx_ready(sc, atid))
  			ath_tx_tid_bar_tx(sc, atid);
  
  		ATH_TX_UNLOCK(sc);
  		/*
  		 * If freeframe is set, then the frame couldn't be
  		 * cloned and bf is still valid.  Just complete/free it.
  		 */
  		if (freeframe)
  			ath_tx_default_comp(sc, bf, fail);
  
  		return;
  	}
  	/*
  	 * Don't bother with the retry check if all frames
  	 * are being failed (eg during queue deletion.)
  	 */
  #if 0
  	if (fail == 0 && ts->ts_status & HAL_TXERR_XRETRY) {
  #endif
  	if (fail == 0 && ts.ts_status != 0) {
  		ATH_TX_UNLOCK(sc);
  		DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: retry_unaggr\n",
  		    __func__);
  		ath_tx_aggr_retry_unaggr(sc, bf);
  		return;
  	}
  
  	/* Success? Complete */
  	DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: TID=%d, seqno %d\n",
  	    __func__, tid, SEQNO(bf->bf_state.bfs_seqno));
  	if (bf->bf_state.bfs_dobaw) {
  		ath_tx_update_baw(sc, an, atid, bf);
  		bf->bf_state.bfs_dobaw = 0;
  		if (!bf->bf_state.bfs_addedbaw)
  			DPRINTF(sc, ATH_DEBUG_SW_TX,
  			    "%s: wasn't added: seqno %d\n",
  			    __func__, SEQNO(bf->bf_state.bfs_seqno));
  	}
  
  	/*
  	 * If the queue is filtered, re-schedule as required.
  	 *
  	 * This is required as there may be a subsequent TX descriptor
  	 * for this end-node that has CLRDMASK set, so it's quite possible
  	 * that a filtered frame will be followed by a non-filtered
  	 * (complete or otherwise) frame.
  	 *
  	 * XXX should we do this before we complete the frame?
  	 */
  	if (atid->isfiltered)
  		ath_tx_tid_filt_comp_complete(sc, atid);
  
  	/*
  	 * Send BAR if required
  	 */
  	if (ath_tx_tid_bar_tx_ready(sc, atid))
  		ath_tx_tid_bar_tx(sc, atid);
  
  	ATH_TX_UNLOCK(sc);
  
  	ath_tx_default_comp(sc, bf, fail);
  	/* bf is freed at this point */
  }
  
  void
  ath_tx_aggr_comp(struct ath_softc *sc, struct ath_buf *bf, int fail)
  {
  	if (bf->bf_state.bfs_aggr)
  		ath_tx_aggr_comp_aggr(sc, bf, fail);
  	else
  		ath_tx_aggr_comp_unaggr(sc, bf, fail);
  }
  
  /*
   * Schedule some packets from the given node/TID to the hardware.
   *
   * This is the aggregate version.
   */
  void
  ath_tx_tid_hw_queue_aggr(struct ath_softc *sc, struct ath_node *an,
      struct ath_tid *tid)
  {
  	struct ath_buf *bf;
  	struct ath_txq *txq = sc->sc_ac2q[tid->ac];
  	struct ieee80211_tx_ampdu *tap;
  	ATH_AGGR_STATUS status;
  	ath_bufhead bf_q;
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: tid=%d\n", __func__, tid->tid);
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/*
  	 * XXX TODO: If we're called for a queue that we're leaking frames to,
  	 * ensure we only leak one.
  	 */
  
  	tap = ath_tx_get_tx_tid(an, tid->tid);
  
  	if (tid->tid == IEEE80211_NONQOS_TID)
  		DPRINTF(sc, ATH_DEBUG_SW_TX, 
  		    "%s: called for TID=NONQOS_TID?\n", __func__);
  
  	for (;;) {
  		status = ATH_AGGR_DONE;
  
  		/*
  		 * If the upper layer has paused the TID, don't
  		 * queue any further packets.
  		 *
  		 * This can also occur from the completion task because
  		 * of packet loss; but as its serialised with this code,
  		 * it won't "appear" half way through queuing packets.
  		 */
  		if (! ath_tx_tid_can_tx_or_sched(sc, tid))
  			break;
  
  		bf = ATH_TID_FIRST(tid);
  		if (bf == NULL) {
  			break;
  		}
  
  		/*
  		 * If the packet doesn't fall within the BAW (eg a NULL
  		 * data frame), schedule it directly; continue.
  		 */
  		if (! bf->bf_state.bfs_dobaw) {
  			DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  			    "%s: non-baw packet\n",
  			    __func__);
  			ATH_TID_REMOVE(tid, bf, bf_list);
  
  			if (bf->bf_state.bfs_nframes > 1)
  				DPRINTF(sc, ATH_DEBUG_SW_TX, 
  				    "%s: aggr=%d, nframes=%d\n",
  				    __func__,
  				    bf->bf_state.bfs_aggr,
  				    bf->bf_state.bfs_nframes);
  
  			/*
  			 * This shouldn't happen - such frames shouldn't
  			 * ever have been queued as an aggregate in the
  			 * first place.  However, make sure the fields
  			 * are correctly setup just to be totally sure.
  			 */
  			bf->bf_state.bfs_aggr = 0;
  			bf->bf_state.bfs_nframes = 1;
  
  			/* Update CLRDMASK just before this frame is queued */
  			ath_tx_update_clrdmask(sc, tid, bf);
  
  			ath_tx_do_ratelookup(sc, bf);
  			ath_tx_calc_duration(sc, bf);
  			ath_tx_calc_protection(sc, bf);
  			ath_tx_set_rtscts(sc, bf);
  			ath_tx_rate_fill_rcflags(sc, bf);
  			ath_tx_setds(sc, bf);
  			ath_hal_clr11n_aggr(sc->sc_ah, bf->bf_desc);
  
  			sc->sc_aggr_stats.aggr_nonbaw_pkt++;
  
  			/* Queue the packet; continue */
  			goto queuepkt;
  		}
  
  		TAILQ_INIT(&bf_q);
  
  		/*
  		 * Do a rate control lookup on the first frame in the
  		 * list. The rate control code needs that to occur
  		 * before it can determine whether to TX.
  		 * It's inaccurate because the rate control code doesn't
  		 * really "do" aggregate lookups, so it only considers
  		 * the size of the first frame.
  		 */
  		ath_tx_do_ratelookup(sc, bf);
  		bf->bf_state.bfs_rc[3].rix = 0;
  		bf->bf_state.bfs_rc[3].tries = 0;
  
  		ath_tx_calc_duration(sc, bf);
  		ath_tx_calc_protection(sc, bf);
  
  		ath_tx_set_rtscts(sc, bf);
  		ath_tx_rate_fill_rcflags(sc, bf);
  
  		status = ath_tx_form_aggr(sc, an, tid, &bf_q);
  
  		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  		    "%s: ath_tx_form_aggr() status=%d\n", __func__, status);
  
  		/*
  		 * No frames to be picked up - out of BAW
  		 */
  		if (TAILQ_EMPTY(&bf_q))
  			break;
  
  		/*
  		 * This assumes that the descriptor list in the ath_bufhead
  		 * are already linked together via bf_next pointers.
  		 */
  		bf = TAILQ_FIRST(&bf_q);
  
  		if (status == ATH_AGGR_8K_LIMITED)
  			sc->sc_aggr_stats.aggr_rts_aggr_limited++;
  
  		/*
  		 * If it's the only frame send as non-aggregate
  		 * assume that ath_tx_form_aggr() has checked
  		 * whether it's in the BAW and added it appropriately.
  		 */
  		if (bf->bf_state.bfs_nframes == 1) {
  			DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  			    "%s: single-frame aggregate\n", __func__);
  
  			/* Update CLRDMASK just before this frame is queued */
  			ath_tx_update_clrdmask(sc, tid, bf);
  
  			bf->bf_state.bfs_aggr = 0;
  			bf->bf_state.bfs_ndelim = 0;
  			ath_tx_setds(sc, bf);
  			ath_hal_clr11n_aggr(sc->sc_ah, bf->bf_desc);
  			if (status == ATH_AGGR_BAW_CLOSED)
  				sc->sc_aggr_stats.aggr_baw_closed_single_pkt++;
  			else
  				sc->sc_aggr_stats.aggr_single_pkt++;
  		} else {
  			DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
  			    "%s: multi-frame aggregate: %d frames, "
  			    "length %d\n",
  			     __func__, bf->bf_state.bfs_nframes,
  			    bf->bf_state.bfs_al);
  			bf->bf_state.bfs_aggr = 1;
  			sc->sc_aggr_stats.aggr_pkts[bf->bf_state.bfs_nframes]++;
  			sc->sc_aggr_stats.aggr_aggr_pkt++;
  
  			/* Update CLRDMASK just before this frame is queued */
  			ath_tx_update_clrdmask(sc, tid, bf);
  
  			/*
  			 * Calculate the duration/protection as required.
  			 */
  			ath_tx_calc_duration(sc, bf);
  			ath_tx_calc_protection(sc, bf);
  
  			/*
  			 * Update the rate and rtscts information based on the
  			 * rate decision made by the rate control code;
  			 * the first frame in the aggregate needs it.
  			 */
  			ath_tx_set_rtscts(sc, bf);
  
  			/*
  			 * Setup the relevant descriptor fields
  			 * for aggregation. The first descriptor
  			 * already points to the rest in the chain.
  			 */
  			ath_tx_setds_11n(sc, bf);
  
  		}
  	queuepkt:
  		/* Set completion handler, multi-frame aggregate or not */
  		bf->bf_comp = ath_tx_aggr_comp;
  
  		if (bf->bf_state.bfs_tid == IEEE80211_NONQOS_TID)
  			DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: TID=16?\n", __func__);
  
  		/*
  		 * Update leak count and frame config if were leaking frames.
  		 *
  		 * XXX TODO: it should update all frames in an aggregate
  		 * correctly!
  		 */
  		ath_tx_leak_count_update(sc, tid, bf);
  
  		/* Punt to txq */
  		ath_tx_handoff(sc, txq, bf);
  
  		/* Track outstanding buffer count to hardware */
  		/* aggregates are "one" buffer */
  		tid->hwq_depth++;
  
  		/*
  		 * Break out if ath_tx_form_aggr() indicated
  		 * there can't be any further progress (eg BAW is full.)
  		 * Checking for an empty txq is done above.
  		 *
  		 * XXX locking on txq here?
  		 */
  		/* XXX TXQ locking */
  		if (txq->axq_aggr_depth >= sc->sc_hwq_limit_aggr ||
  		    (status == ATH_AGGR_BAW_CLOSED ||
  		     status == ATH_AGGR_LEAK_CLOSED))
  			break;
  	}
  }
  
  /*
   * Schedule some packets from the given node/TID to the hardware.
   *
   * XXX TODO: this routine doesn't enforce the maximum TXQ depth.
   * It just dumps frames into the TXQ.  We should limit how deep
   * the transmit queue can grow for frames dispatched to the given
   * TXQ.
   *
   * To avoid locking issues, either we need to own the TXQ lock
   * at this point, or we need to pass in the maximum frame count
   * from the caller.
   */
  void
  ath_tx_tid_hw_queue_norm(struct ath_softc *sc, struct ath_node *an,
      struct ath_tid *tid)
  {
  	struct ath_buf *bf;
  	struct ath_txq *txq = sc->sc_ac2q[tid->ac];
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: node %p: TID %d: called\n",
  	    __func__, an, tid->tid);
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/* Check - is AMPDU pending or running? then print out something */
  	if (ath_tx_ampdu_pending(sc, an, tid->tid))
  		DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: tid=%d, ampdu pending?\n",
  		    __func__, tid->tid);
  	if (ath_tx_ampdu_running(sc, an, tid->tid))
  		DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: tid=%d, ampdu running?\n",
  		    __func__, tid->tid);
  
  	for (;;) {
  
  		/*
  		 * If the upper layers have paused the TID, don't
  		 * queue any further packets.
  		 *
  		 * XXX if we are leaking frames, make sure we decrement
  		 * that counter _and_ we continue here.
  		 */
  		if (! ath_tx_tid_can_tx_or_sched(sc, tid))
  			break;
  
  		bf = ATH_TID_FIRST(tid);
  		if (bf == NULL) {
  			break;
  		}
  
  		ATH_TID_REMOVE(tid, bf, bf_list);
  
  		/* Sanity check! */
  		if (tid->tid != bf->bf_state.bfs_tid) {
  			DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: bfs_tid %d !="
  			    " tid %d\n", __func__, bf->bf_state.bfs_tid,
  			    tid->tid);
  		}
  		/* Normal completion handler */
  		bf->bf_comp = ath_tx_normal_comp;
  
  		/*
  		 * Override this for now, until the non-aggregate
  		 * completion handler correctly handles software retransmits.
  		 */
  		bf->bf_state.bfs_txflags |= HAL_TXDESC_CLRDMASK;
  
  		/* Update CLRDMASK just before this frame is queued */
  		ath_tx_update_clrdmask(sc, tid, bf);
  
  		/* Program descriptors + rate control */
  		ath_tx_do_ratelookup(sc, bf);
  		ath_tx_calc_duration(sc, bf);
  		ath_tx_calc_protection(sc, bf);
  		ath_tx_set_rtscts(sc, bf);
  		ath_tx_rate_fill_rcflags(sc, bf);
  		ath_tx_setds(sc, bf);
  
  		/*
  		 * Update the current leak count if
  		 * we're leaking frames; and set the
  		 * MORE flag as appropriate.
  		 */
  		ath_tx_leak_count_update(sc, tid, bf);
  
  		/* Track outstanding buffer count to hardware */
  		/* aggregates are "one" buffer */
  		tid->hwq_depth++;
  
  		/* Punt to hardware or software txq */
  		ath_tx_handoff(sc, txq, bf);
  	}
  }
  
  /*
   * Schedule some packets to the given hardware queue.
   *
   * This function walks the list of TIDs (ie, ath_node TIDs
   * with queued traffic) and attempts to schedule traffic
   * from them.
   *
   * TID scheduling is implemented as a FIFO, with TIDs being
   * added to the end of the queue after some frames have been
   * scheduled.
   */
  void
  ath_txq_sched(struct ath_softc *sc, struct ath_txq *txq)
  {
  	struct ath_tid *tid, *next, *last;
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	/*
  	 * Don't schedule if the hardware queue is busy.
  	 * This (hopefully) gives some more time to aggregate
  	 * some packets in the aggregation queue.
  	 *
  	 * XXX It doesn't stop a parallel sender from sneaking
  	 * in transmitting a frame!
  	 */
  	/* XXX TXQ locking */
  	if (txq->axq_aggr_depth + txq->fifo.axq_depth >= sc->sc_hwq_limit_aggr) {
  		sc->sc_aggr_stats.aggr_sched_nopkt++;
  		return;
  	}
  	if (txq->axq_depth >= sc->sc_hwq_limit_nonaggr) {
  		sc->sc_aggr_stats.aggr_sched_nopkt++;
  		return;
  	}
  
  	last = TAILQ_LAST(&txq->axq_tidq, axq_t_s);
  
  	TAILQ_FOREACH_SAFE(tid, &txq->axq_tidq, axq_qelem, next) {
  		/*
  		 * Suspend paused queues here; they'll be resumed
  		 * once the addba completes or times out.
  		 */
  		DPRINTF(sc, ATH_DEBUG_SW_TX, "%s: tid=%d, paused=%d\n",
  		    __func__, tid->tid, tid->paused);
  		ath_tx_tid_unsched(sc, tid);
  		/*
  		 * This node may be in power-save and we're leaking
  		 * a frame; be careful.
  		 */
  		if (! ath_tx_tid_can_tx_or_sched(sc, tid)) {
  			goto loop_done;
  		}
  		if (ath_tx_ampdu_running(sc, tid->an, tid->tid))
  			ath_tx_tid_hw_queue_aggr(sc, tid->an, tid);
  		else
  			ath_tx_tid_hw_queue_norm(sc, tid->an, tid);
  
  		/* Not empty? Re-schedule */
  		if (tid->axq_depth != 0)
  			ath_tx_tid_sched(sc, tid);
  
  		/*
  		 * Give the software queue time to aggregate more
  		 * packets.  If we aren't running aggregation then
  		 * we should still limit the hardware queue depth.
  		 */
  		/* XXX TXQ locking */
  		if (txq->axq_aggr_depth + txq->fifo.axq_depth >= sc->sc_hwq_limit_aggr) {
  			break;
  		}
  		if (txq->axq_depth >= sc->sc_hwq_limit_nonaggr) {
  			break;
  		}
  loop_done:
  		/*
  		 * If this was the last entry on the original list, stop.
  		 * Otherwise nodes that have been rescheduled onto the end
  		 * of the TID FIFO list will just keep being rescheduled.
  		 *
  		 * XXX What should we do about nodes that were paused
  		 * but are pending a leaking frame in response to a ps-poll?
  		 * They'll be put at the front of the list; so they'll
  		 * prematurely trigger this condition! Ew.
  		 */
  		if (tid == last)
  			break;
  	}
  }
  
  /*
   * TX addba handling
   */
  
  /*
   * Return net80211 TID struct pointer, or NULL for none
   */
  struct ieee80211_tx_ampdu *
  ath_tx_get_tx_tid(struct ath_node *an, int tid)
  {
  	struct ieee80211_node *ni = &an->an_node;
  	struct ieee80211_tx_ampdu *tap;
  
  	if (tid == IEEE80211_NONQOS_TID)
  		return NULL;
  
  	tap = &ni->ni_tx_ampdu[tid];
  	return tap;
  }
  
  /*
   * Is AMPDU-TX running?
   */
  static int
  ath_tx_ampdu_running(struct ath_softc *sc, struct ath_node *an, int tid)
  {
  	struct ieee80211_tx_ampdu *tap;
  
  	if (tid == IEEE80211_NONQOS_TID)
  		return 0;
  
  	tap = ath_tx_get_tx_tid(an, tid);
  	if (tap == NULL)
  		return 0;	/* Not valid; default to not running */
  
  	return !! (tap->txa_flags & IEEE80211_AGGR_RUNNING);
  }
  
  /*
   * Is AMPDU-TX negotiation pending?
   */
  static int
  ath_tx_ampdu_pending(struct ath_softc *sc, struct ath_node *an, int tid)
  {
  	struct ieee80211_tx_ampdu *tap;
  
  	if (tid == IEEE80211_NONQOS_TID)
  		return 0;
  
  	tap = ath_tx_get_tx_tid(an, tid);
  	if (tap == NULL)
  		return 0;	/* Not valid; default to not pending */
  
  	return !! (tap->txa_flags & IEEE80211_AGGR_XCHGPEND);
  }
  
  /*
   * Is AMPDU-TX pending for the given TID?
   */
  
  
  /*
   * Method to handle sending an ADDBA request.
   *
   * We tap this so the relevant flags can be set to pause the TID
   * whilst waiting for the response.
   *
   * XXX there's no timeout handler we can override?
   */
  int
  ath_addba_request(struct ieee80211_node *ni, struct ieee80211_tx_ampdu *tap,
      int dialogtoken, int baparamset, int batimeout)
  {
  	struct ath_softc *sc = ni->ni_ic->ic_softc;
  	int tid = tap->txa_tid;
  	struct ath_node *an = ATH_NODE(ni);
  	struct ath_tid *atid = &an->an_tid[tid];
  
  	/*
  	 * XXX danger Will Robinson!
  	 *
  	 * Although the taskqueue may be running and scheduling some more
  	 * packets, these should all be _before_ the addba sequence number.
  	 * However, net80211 will keep self-assigning sequence numbers
  	 * until addba has been negotiated.
  	 *
  	 * In the past, these packets would be "paused" (which still works
  	 * fine, as they're being scheduled to the driver in the same
  	 * serialised method which is calling the addba request routine)
  	 * and when the aggregation session begins, they'll be dequeued
  	 * as aggregate packets and added to the BAW. However, now there's
  	 * a "bf->bf_state.bfs_dobaw" flag, and this isn't set for these
  	 * packets. Thus they never get included in the BAW tracking and
  	 * this can cause the initial burst of packets after the addba
  	 * negotiation to "hang", as they quickly fall outside the BAW.
  	 *
  	 * The "eventual" solution should be to tag these packets with
  	 * dobaw. Although net80211 has given us a sequence number,
  	 * it'll be "after" the left edge of the BAW and thus it'll
  	 * fall within it.
  	 */
  	ATH_TX_LOCK(sc);
  	/*
  	 * This is a bit annoying.  Until net80211 HT code inherits some
  	 * (any) locking, we may have this called in parallel BUT only
  	 * one response/timeout will be called.  Grr.
  	 */
  	if (atid->addba_tx_pending == 0) {
  		ath_tx_tid_pause(sc, atid);
  		atid->addba_tx_pending = 1;
  	}
  	ATH_TX_UNLOCK(sc);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL,
  	    "%s: %6D: called; dialogtoken=%d, baparamset=%d, batimeout=%d\n",
  	    __func__,
  	    ni->ni_macaddr,
  	    ":",
  	    dialogtoken, baparamset, batimeout);
  	DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL,
  	    "%s: txa_start=%d, ni_txseqs=%d\n",
  	    __func__, tap->txa_start, ni->ni_txseqs[tid]);
  
  	return sc->sc_addba_request(ni, tap, dialogtoken, baparamset,
  	    batimeout);
  }
  
  /*
   * Handle an ADDBA response.
   *
   * We unpause the queue so TX'ing can resume.
   *
   * Any packets TX'ed from this point should be "aggregate" (whether
   * aggregate or not) so the BAW is updated.
   *
   * Note! net80211 keeps self-assigning sequence numbers until
   * ampdu is negotiated. This means the initially-negotiated BAW left
   * edge won't match the ni->ni_txseq.
   *
   * So, being very dirty, the BAW left edge is "slid" here to match
   * ni->ni_txseq.
   *
   * What likely SHOULD happen is that all packets subsequent to the
   * addba request should be tagged as aggregate and queued as non-aggregate
   * frames; thus updating the BAW. For now though, I'll just slide the
   * window.
   */
  int
  ath_addba_response(struct ieee80211_node *ni, struct ieee80211_tx_ampdu *tap,
      int status, int code, int batimeout)
  {
  	struct ath_softc *sc = ni->ni_ic->ic_softc;
  	int tid = tap->txa_tid;
  	struct ath_node *an = ATH_NODE(ni);
  	struct ath_tid *atid = &an->an_tid[tid];
  	int r;
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL,
  	    "%s: %6D: called; status=%d, code=%d, batimeout=%d\n", __func__,
  	    ni->ni_macaddr,
  	    ":",
  	    status, code, batimeout);
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL,
  	    "%s: txa_start=%d, ni_txseqs=%d\n",
  	    __func__, tap->txa_start, ni->ni_txseqs[tid]);
  
  	/*
  	 * Call this first, so the interface flags get updated
  	 * before the TID is unpaused. Otherwise a race condition
  	 * exists where the unpaused TID still doesn't yet have
  	 * IEEE80211_AGGR_RUNNING set.
  	 */
  	r = sc->sc_addba_response(ni, tap, status, code, batimeout);
  
  	ATH_TX_LOCK(sc);
  	atid->addba_tx_pending = 0;
  	/*
  	 * XXX dirty!
  	 * Slide the BAW left edge to wherever net80211 left it for us.
  	 * Read above for more information.
  	 */
  	tap->txa_start = ni->ni_txseqs[tid];
  	ath_tx_tid_resume(sc, atid);
  	ATH_TX_UNLOCK(sc);
  	return r;
  }
  
  
  /*
   * Stop ADDBA on a queue.
   *
   * This can be called whilst BAR TX is currently active on the queue,
   * so make sure this is unblocked before continuing.
   */
  void
  ath_addba_stop(struct ieee80211_node *ni, struct ieee80211_tx_ampdu *tap)
  {
  	struct ath_softc *sc = ni->ni_ic->ic_softc;
  	int tid = tap->txa_tid;
  	struct ath_node *an = ATH_NODE(ni);
  	struct ath_tid *atid = &an->an_tid[tid];
  	ath_bufhead bf_cq;
  	struct ath_buf *bf;
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL, "%s: %6D: called\n",
  	    __func__,
  	    ni->ni_macaddr,
  	    ":");
  
  	/*
  	 * Pause TID traffic early, so there aren't any races
  	 * Unblock the pending BAR held traffic, if it's currently paused.
  	 */
  	ATH_TX_LOCK(sc);
  	ath_tx_tid_pause(sc, atid);
  	if (atid->bar_wait) {
  		/*
  		 * bar_unsuspend() expects bar_tx == 1, as it should be
  		 * called from the TX completion path.  This quietens
  		 * the warning.  It's cleared for us anyway.
  		 */
  		atid->bar_tx = 1;
  		ath_tx_tid_bar_unsuspend(sc, atid);
  	}
  	ATH_TX_UNLOCK(sc);
  
  	/* There's no need to hold the TXQ lock here */
  	sc->sc_addba_stop(ni, tap);
  
  	/*
  	 * ath_tx_tid_cleanup will resume the TID if possible, otherwise
  	 * it'll set the cleanup flag, and it'll be unpaused once
  	 * things have been cleaned up.
  	 */
  	TAILQ_INIT(&bf_cq);
  	ATH_TX_LOCK(sc);
  
  	/*
  	 * In case there's a followup call to this, only call it
  	 * if we don't have a cleanup in progress.
  	 *
  	 * Since we've paused the queue above, we need to make
  	 * sure we unpause if there's already a cleanup in
  	 * progress - it means something else is also doing
  	 * this stuff, so we don't need to also keep it paused.
  	 */
  	if (atid->cleanup_inprogress) {
  		ath_tx_tid_resume(sc, atid);
  	} else {
  		ath_tx_tid_cleanup(sc, an, tid, &bf_cq);
  		/*
  		 * Unpause the TID if no cleanup is required.
  		 */
  		if (! atid->cleanup_inprogress)
  			ath_tx_tid_resume(sc, atid);
  	}
  	ATH_TX_UNLOCK(sc);
  
  	/* Handle completing frames and fail them */
  	while ((bf = TAILQ_FIRST(&bf_cq)) != NULL) {
  		TAILQ_REMOVE(&bf_cq, bf, bf_list);
  		ath_tx_default_comp(sc, bf, 1);
  	}
  
  }
  
  /*
   * Handle a node reassociation.
   *
   * We may have a bunch of frames queued to the hardware; those need
   * to be marked as cleanup.
   */
  void
  ath_tx_node_reassoc(struct ath_softc *sc, struct ath_node *an)
  {
  	struct ath_tid *tid;
  	int i;
  	ath_bufhead bf_cq;
  	struct ath_buf *bf;
  
  	TAILQ_INIT(&bf_cq);
  
  	ATH_TX_UNLOCK_ASSERT(sc);
  
  	ATH_TX_LOCK(sc);
  	for (i = 0; i < IEEE80211_TID_SIZE; i++) {
  		tid = &an->an_tid[i];
  		if (tid->hwq_depth == 0)
  			continue;
  		DPRINTF(sc, ATH_DEBUG_NODE,
  		    "%s: %6D: TID %d: cleaning up TID\n",
  		    __func__,
  		    an->an_node.ni_macaddr,
  		    ":",
  		    i);
  		/*
  		 * In case there's a followup call to this, only call it
  		 * if we don't have a cleanup in progress.
  		 */
  		if (! tid->cleanup_inprogress) {
  			ath_tx_tid_pause(sc, tid);
  			ath_tx_tid_cleanup(sc, an, i, &bf_cq);
  			/*
  			 * Unpause the TID if no cleanup is required.
  			 */
  			if (! tid->cleanup_inprogress)
  				ath_tx_tid_resume(sc, tid);
  		}
  	}
  	ATH_TX_UNLOCK(sc);
  
  	/* Handle completing frames and fail them */
  	while ((bf = TAILQ_FIRST(&bf_cq)) != NULL) {
  		TAILQ_REMOVE(&bf_cq, bf, bf_list);
  		ath_tx_default_comp(sc, bf, 1);
  	}
  }
  
  /*
   * Note: net80211 bar_timeout() doesn't call this function on BAR failure;
   * it simply tears down the aggregation session. Ew.
   *
   * It however will call ieee80211_ampdu_stop() which will call
   * ic->ic_addba_stop().
   *
   * XXX This uses a hard-coded max BAR count value; the whole
   * XXX BAR TX success or failure should be better handled!
   */
  void
  ath_bar_response(struct ieee80211_node *ni, struct ieee80211_tx_ampdu *tap,
      int status)
  {
  	struct ath_softc *sc = ni->ni_ic->ic_softc;
  	int tid = tap->txa_tid;
  	struct ath_node *an = ATH_NODE(ni);
  	struct ath_tid *atid = &an->an_tid[tid];
  	int attempts = tap->txa_attempts;
  	int old_txa_start;
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_BAR,
  	    "%s: %6D: called; txa_tid=%d, atid->tid=%d, status=%d, attempts=%d, txa_start=%d, txa_seqpending=%d\n",
  	    __func__,
  	    ni->ni_macaddr,
  	    ":",
  	    tap->txa_tid,
  	    atid->tid,
  	    status,
  	    attempts,
  	    tap->txa_start,
  	    tap->txa_seqpending);
  
  	/* Note: This may update the BAW details */
  	/*
  	 * XXX What if this does slide the BAW along? We need to somehow
  	 * XXX either fix things when it does happen, or prevent the
  	 * XXX seqpending value to be anything other than exactly what
  	 * XXX the hell we want!
  	 *
  	 * XXX So for now, how I do this inside the TX lock for now
  	 * XXX and just correct it afterwards? The below condition should
  	 * XXX never happen and if it does I need to fix all kinds of things.
  	 */
  	ATH_TX_LOCK(sc);
  	old_txa_start = tap->txa_start;
  	sc->sc_bar_response(ni, tap, status);
  	if (tap->txa_start != old_txa_start) {
  		device_printf(sc->sc_dev, "%s: tid=%d; txa_start=%d, old=%d, adjusting\n",
  		    __func__,
  		    tid,
  		    tap->txa_start,
  		    old_txa_start);
  	}
  	tap->txa_start = old_txa_start;
  	ATH_TX_UNLOCK(sc);
  
  	/* Unpause the TID */
  	/*
  	 * XXX if this is attempt=50, the TID will be downgraded
  	 * XXX to a non-aggregate session. So we must unpause the
  	 * XXX TID here or it'll never be done.
  	 *
  	 * Also, don't call it if bar_tx/bar_wait are 0; something
  	 * has beaten us to the punch? (XXX figure out what?)
  	 */
  	if (status == 0 || attempts == 50) {
  		ATH_TX_LOCK(sc);
  		if (atid->bar_tx == 0 || atid->bar_wait == 0)
  			DPRINTF(sc, ATH_DEBUG_SW_TX_BAR,
  			    "%s: huh? bar_tx=%d, bar_wait=%d\n",
  			    __func__,
  			    atid->bar_tx, atid->bar_wait);
  		else
  			ath_tx_tid_bar_unsuspend(sc, atid);
  		ATH_TX_UNLOCK(sc);
  	}
  }
  
  /*
   * This is called whenever the pending ADDBA request times out.
   * Unpause and reschedule the TID.
   */
  void
  ath_addba_response_timeout(struct ieee80211_node *ni,
      struct ieee80211_tx_ampdu *tap)
  {
  	struct ath_softc *sc = ni->ni_ic->ic_softc;
  	int tid = tap->txa_tid;
  	struct ath_node *an = ATH_NODE(ni);
  	struct ath_tid *atid = &an->an_tid[tid];
  
  	DPRINTF(sc, ATH_DEBUG_SW_TX_CTRL,
  	    "%s: %6D: TID=%d, called; resuming\n",
  	    __func__,
  	    ni->ni_macaddr,
  	    ":",
  	    tid);
  
  	ATH_TX_LOCK(sc);
  	atid->addba_tx_pending = 0;
  	ATH_TX_UNLOCK(sc);
  
  	/* Note: This updates the aggregate state to (again) pending */
  	sc->sc_addba_response_timeout(ni, tap);
  
  	/* Unpause the TID; which reschedules it */
  	ATH_TX_LOCK(sc);
  	ath_tx_tid_resume(sc, atid);
  	ATH_TX_UNLOCK(sc);
  }
  
  /*
   * Check if a node is asleep or not.
   */
  int
  ath_tx_node_is_asleep(struct ath_softc *sc, struct ath_node *an)
  {
  
  	ATH_TX_LOCK_ASSERT(sc);
  
  	return (an->an_is_powersave);
  }
  
  /*
   * Mark a node as currently "in powersaving."
   * This suspends all traffic on the node.
   *
   * This must be called with the node/tx locks free.
   *
   * XXX TODO: the locking silliness below is due to how the node
   * locking currently works.  Right now, the node lock is grabbed
   * to do rate control lookups and these are done with the TX
   * queue lock held.  This means the node lock can't be grabbed
   * first here or a LOR will occur.
   *
   * Eventually (hopefully!) the TX path code will only grab
   * the TXQ lock when transmitting and the ath_node lock when
   * doing node/TID operations.  There are other complications -
   * the sched/unsched operations involve walking the per-txq
   * 'active tid' list and this requires both locks to be held.
   */
  void
  ath_tx_node_sleep(struct ath_softc *sc, struct ath_node *an)
  {
  	struct ath_tid *atid;
  	struct ath_txq *txq;
  	int tid;
  
  	ATH_TX_UNLOCK_ASSERT(sc);
  
  	/* Suspend all traffic on the node */
  	ATH_TX_LOCK(sc);
  
  	if (an->an_is_powersave) {
  		DPRINTF(sc, ATH_DEBUG_XMIT,
  		    "%s: %6D: node was already asleep!\n",
  		    __func__, an->an_node.ni_macaddr, ":");
  		ATH_TX_UNLOCK(sc);
  		return;
  	}
  
  	for (tid = 0; tid < IEEE80211_TID_SIZE; tid++) {
  		atid = &an->an_tid[tid];
  		txq = sc->sc_ac2q[atid->ac];
  
  		ath_tx_tid_pause(sc, atid);
  	}
  
  	/* Mark node as in powersaving */
  	an->an_is_powersave = 1;
  
  	ATH_TX_UNLOCK(sc);
  }
  
  /*
   * Mark a node as currently "awake."
   * This resumes all traffic to the node.
   */
  void
  ath_tx_node_wakeup(struct ath_softc *sc, struct ath_node *an)
  {
  	struct ath_tid *atid;
  	struct ath_txq *txq;
  	int tid;
  
  	ATH_TX_UNLOCK_ASSERT(sc);
  
  	ATH_TX_LOCK(sc);
  
  	/* !? */
  	if (an->an_is_powersave == 0) {
  		ATH_TX_UNLOCK(sc);
  		DPRINTF(sc, ATH_DEBUG_XMIT,
  		    "%s: an=%p: node was already awake\n",
  		    __func__, an);
  		return;
  	}
  
  	/* Mark node as awake */
  	an->an_is_powersave = 0;
  	/*
  	 * Clear any pending leaked frame requests
  	 */
  	an->an_leak_count = 0;
  
  	for (tid = 0; tid < IEEE80211_TID_SIZE; tid++) {
  		atid = &an->an_tid[tid];
  		txq = sc->sc_ac2q[atid->ac];
  
  		ath_tx_tid_resume(sc, atid);
  	}
  	ATH_TX_UNLOCK(sc);
  }
  
  static int
  ath_legacy_dma_txsetup(struct ath_softc *sc)
  {
  
  	/* nothing new needed */
  	return (0);
  }
  
  static int
  ath_legacy_dma_txteardown(struct ath_softc *sc)
  {
  
  	/* nothing new needed */
  	return (0);
  }
  
  void
  ath_xmit_setup_legacy(struct ath_softc *sc)
  {
  	/*
  	 * For now, just set the descriptor length to sizeof(ath_desc);
  	 * worry about extracting the real length out of the HAL later.
  	 */
  	sc->sc_tx_desclen = sizeof(struct ath_desc);
  	sc->sc_tx_statuslen = sizeof(struct ath_desc);
  	sc->sc_tx_nmaps = 1;	/* only one buffer per TX desc */
  
  	sc->sc_tx.xmit_setup = ath_legacy_dma_txsetup;
  	sc->sc_tx.xmit_teardown = ath_legacy_dma_txteardown;
  	sc->sc_tx.xmit_attach_comp_func = ath_legacy_attach_comp_func;
  
  	sc->sc_tx.xmit_dma_restart = ath_legacy_tx_dma_restart;
  	sc->sc_tx.xmit_handoff = ath_legacy_xmit_handoff;
  
  	sc->sc_tx.xmit_drain = ath_legacy_tx_drain;
  }
  