Fix common misspellings

[mirror_ubuntu-artful-kernel.git] / drivers / net / wireless / ath / ath9k / xmit.c

/*
 * Copyright (c) 2008-2009 Atheros Communications Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "ath9k.h"
#include "ar9003_mac.h"

#define BITS_PER_BYTE           8
#define OFDM_PLCP_BITS          22
#define HT_RC_2_STREAMS(_rc)    ((((_rc) & 0x78) >> 3) + 1)
#define L_STF                   8
#define L_LTF                   8
#define L_SIG                   4
#define HT_SIG                  8
#define HT_STF                  4
#define HT_LTF(_ns)             (4 * (_ns))
#define SYMBOL_TIME(_ns)        ((_ns) << 2) /* ns * 4 us */
#define SYMBOL_TIME_HALFGI(_ns) (((_ns) * 18 + 4) / 5)  /* ns * 3.6 us */
#define NUM_SYMBOLS_PER_USEC(_usec) (_usec >> 2)
#define NUM_SYMBOLS_PER_USEC_HALFGI(_usec) (((_usec*5)-4)/18)


static u16 bits_per_symbol[][2] = {
        /* 20MHz 40MHz */
        {    26,   54 },     /*  0: BPSK */
        {    52,  108 },     /*  1: QPSK 1/2 */
        {    78,  162 },     /*  2: QPSK 3/4 */
        {   104,  216 },     /*  3: 16-QAM 1/2 */
        {   156,  324 },     /*  4: 16-QAM 3/4 */
        {   208,  432 },     /*  5: 64-QAM 2/3 */
        {   234,  486 },     /*  6: 64-QAM 3/4 */
        {   260,  540 },     /*  7: 64-QAM 5/6 */
};

#define IS_HT_RATE(_rate)     ((_rate) & 0x80)

static void ath_tx_send_normal(struct ath_softc *sc, struct ath_txq *txq,
                               struct ath_atx_tid *tid,
                               struct list_head *bf_head);
static void ath_tx_complete_buf(struct ath_softc *sc, struct ath_buf *bf,
                                struct ath_txq *txq, struct list_head *bf_q,
                                struct ath_tx_status *ts, int txok, int sendbar);
static void ath_tx_txqaddbuf(struct ath_softc *sc, struct ath_txq *txq,
                             struct list_head *head);
static void ath_buf_set_rate(struct ath_softc *sc, struct ath_buf *bf, int len);
static void ath_tx_rc_status(struct ath_softc *sc, struct ath_buf *bf,
                             struct ath_tx_status *ts, int nframes, int nbad,
                             int txok, bool update_rc);
static void ath_tx_update_baw(struct ath_softc *sc, struct ath_atx_tid *tid,
                              int seqno);

enum {
        MCS_HT20,
        MCS_HT20_SGI,
        MCS_HT40,
        MCS_HT40_SGI,
};

static int ath_max_4ms_framelen[4][32] = {
        [MCS_HT20] = {
                3212,  6432,  9648,  12864,  19300,  25736,  28952,  32172,
                6424,  12852, 19280, 25708,  38568,  51424,  57852,  64280,
                9628,  19260, 28896, 38528,  57792,  65532,  65532,  65532,
                12828, 25656, 38488, 51320,  65532,  65532,  65532,  65532,
        },
        [MCS_HT20_SGI] = {
                3572,  7144,  10720,  14296,  21444,  28596,  32172,  35744,
                7140,  14284, 21428,  28568,  42856,  57144,  64288,  65532,
                10700, 21408, 32112,  42816,  64228,  65532,  65532,  65532,
                14256, 28516, 42780,  57040,  65532,  65532,  65532,  65532,
        },
        [MCS_HT40] = {
                6680,  13360,  20044,  26724,  40092,  53456,  60140,  65532,
                13348, 26700,  40052,  53400,  65532,  65532,  65532,  65532,
                20004, 40008,  60016,  65532,  65532,  65532,  65532,  65532,
                26644, 53292,  65532,  65532,  65532,  65532,  65532,  65532,
        },
        [MCS_HT40_SGI] = {
                7420,  14844,  22272,  29696,  44544,  59396,  65532,  65532,
                14832, 29668,  44504,  59340,  65532,  65532,  65532,  65532,
                22232, 44464,  65532,  65532,  65532,  65532,  65532,  65532,
                29616, 59232,  65532,  65532,  65532,  65532,  65532,  65532,
        }
};

/*********************/
/* Aggregation logic */
/*********************/

static void ath_tx_queue_tid(struct ath_txq *txq, struct ath_atx_tid *tid)
{
        struct ath_atx_ac *ac = tid->ac;

        if (tid->paused)
                return;

        if (tid->sched)
                return;

        tid->sched = true;
        list_add_tail(&tid->list, &ac->tid_q);

        if (ac->sched)
                return;

        ac->sched = true;
        list_add_tail(&ac->list, &txq->axq_acq);
}

static void ath_tx_resume_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
{
        struct ath_txq *txq = tid->ac->txq;

        WARN_ON(!tid->paused);

        spin_lock_bh(&txq->axq_lock);
        tid->paused = false;

        if (list_empty(&tid->buf_q))
                goto unlock;

        ath_tx_queue_tid(txq, tid);
        ath_txq_schedule(sc, txq);
unlock:
        spin_unlock_bh(&txq->axq_lock);
}

static struct ath_frame_info *get_frame_info(struct sk_buff *skb)
{
        struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
        BUILD_BUG_ON(sizeof(struct ath_frame_info) >
                     sizeof(tx_info->rate_driver_data));
        return (struct ath_frame_info *) &tx_info->rate_driver_data[0];
}

static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
{
        struct ath_txq *txq = tid->ac->txq;
        struct ath_buf *bf;
        struct list_head bf_head;
        struct ath_tx_status ts;
        struct ath_frame_info *fi;

        INIT_LIST_HEAD(&bf_head);

        memset(&ts, 0, sizeof(ts));
        spin_lock_bh(&txq->axq_lock);

        while (!list_empty(&tid->buf_q)) {
                bf = list_first_entry(&tid->buf_q, struct ath_buf, list);
                list_move_tail(&bf->list, &bf_head);

                spin_unlock_bh(&txq->axq_lock);
                fi = get_frame_info(bf->bf_mpdu);
                if (fi->retries) {
                        ath_tx_update_baw(sc, tid, fi->seqno);
                        ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0, 1);
                } else {
                        ath_tx_send_normal(sc, txq, NULL, &bf_head);
                }
                spin_lock_bh(&txq->axq_lock);
        }

        spin_unlock_bh(&txq->axq_lock);
}

static void ath_tx_update_baw(struct ath_softc *sc, struct ath_atx_tid *tid,
                              int seqno)
{
        int index, cindex;

        index  = ATH_BA_INDEX(tid->seq_start, seqno);
        cindex = (tid->baw_head + index) & (ATH_TID_MAX_BUFS - 1);

        __clear_bit(cindex, tid->tx_buf);

        while (tid->baw_head != tid->baw_tail && !test_bit(tid->baw_head, tid->tx_buf)) {
                INCR(tid->seq_start, IEEE80211_SEQ_MAX);
                INCR(tid->baw_head, ATH_TID_MAX_BUFS);
        }
}

static void ath_tx_addto_baw(struct ath_softc *sc, struct ath_atx_tid *tid,
                             u16 seqno)
{
        int index, cindex;

        index  = ATH_BA_INDEX(tid->seq_start, seqno);
        cindex = (tid->baw_head + index) & (ATH_TID_MAX_BUFS - 1);
        __set_bit(cindex, tid->tx_buf);

        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);
        }
}

/*
 * 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_tid_drain(struct ath_softc *sc, struct ath_txq *txq,
                          struct ath_atx_tid *tid)

{
        struct ath_buf *bf;
        struct list_head bf_head;
        struct ath_tx_status ts;
        struct ath_frame_info *fi;

        memset(&ts, 0, sizeof(ts));
        INIT_LIST_HEAD(&bf_head);

        for (;;) {
                if (list_empty(&tid->buf_q))
                        break;

                bf = list_first_entry(&tid->buf_q, struct ath_buf, list);
                list_move_tail(&bf->list, &bf_head);

                fi = get_frame_info(bf->bf_mpdu);
                if (fi->retries)
                        ath_tx_update_baw(sc, tid, fi->seqno);

                spin_unlock(&txq->axq_lock);
                ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0, 0);
                spin_lock(&txq->axq_lock);
        }

        tid->seq_next = tid->seq_start;
        tid->baw_tail = tid->baw_head;
}

static void ath_tx_set_retry(struct ath_softc *sc, struct ath_txq *txq,
                             struct sk_buff *skb)
{
        struct ath_frame_info *fi = get_frame_info(skb);
        struct ieee80211_hdr *hdr;

        TX_STAT_INC(txq->axq_qnum, a_retries);
        if (fi->retries++ > 0)
                return;

        hdr = (struct ieee80211_hdr *)skb->data;
        hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_RETRY);
}

static struct ath_buf *ath_tx_get_buffer(struct ath_softc *sc)
{
        struct ath_buf *bf = NULL;

        spin_lock_bh(&sc->tx.txbuflock);

        if (unlikely(list_empty(&sc->tx.txbuf))) {
                spin_unlock_bh(&sc->tx.txbuflock);
                return NULL;
        }

        bf = list_first_entry(&sc->tx.txbuf, struct ath_buf, list);
        list_del(&bf->list);

        spin_unlock_bh(&sc->tx.txbuflock);

        return bf;
}

static void ath_tx_return_buffer(struct ath_softc *sc, struct ath_buf *bf)
{
        spin_lock_bh(&sc->tx.txbuflock);
        list_add_tail(&bf->list, &sc->tx.txbuf);
        spin_unlock_bh(&sc->tx.txbuflock);
}

static struct ath_buf* ath_clone_txbuf(struct ath_softc *sc, struct ath_buf *bf)
{
        struct ath_buf *tbf;

        tbf = ath_tx_get_buffer(sc);
        if (WARN_ON(!tbf))
                return NULL;

        ATH_TXBUF_RESET(tbf);

        tbf->bf_mpdu = bf->bf_mpdu;
        tbf->bf_buf_addr = bf->bf_buf_addr;
        memcpy(tbf->bf_desc, bf->bf_desc, sc->sc_ah->caps.tx_desc_len);
        tbf->bf_state = bf->bf_state;

        return tbf;
}

static void ath_tx_count_frames(struct ath_softc *sc, struct ath_buf *bf,
                                struct ath_tx_status *ts, int txok,
                                int *nframes, int *nbad)
{
        struct ath_frame_info *fi;
        u16 seq_st = 0;
        u32 ba[WME_BA_BMP_SIZE >> 5];
        int ba_index;
        int isaggr = 0;

        *nbad = 0;
        *nframes = 0;

        isaggr = bf_isaggr(bf);
        if (isaggr) {
                seq_st = ts->ts_seqnum;
                memcpy(ba, &ts->ba_low, WME_BA_BMP_SIZE >> 3);
        }

        while (bf) {
                fi = get_frame_info(bf->bf_mpdu);
                ba_index = ATH_BA_INDEX(seq_st, fi->seqno);

                (*nframes)++;
                if (!txok || (isaggr && !ATH_BA_ISSET(ba, ba_index)))
                        (*nbad)++;

                bf = bf->bf_next;
        }
}


static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
                                 struct ath_buf *bf, struct list_head *bf_q,
                                 struct ath_tx_status *ts, int txok, bool retry)
{
        struct ath_node *an = NULL;
        struct sk_buff *skb;
        struct ieee80211_sta *sta;
        struct ieee80211_hw *hw = sc->hw;
        struct ieee80211_hdr *hdr;
        struct ieee80211_tx_info *tx_info;
        struct ath_atx_tid *tid = NULL;
        struct ath_buf *bf_next, *bf_last = bf->bf_lastbf;
        struct list_head bf_head, bf_pending;
        u16 seq_st = 0, acked_cnt = 0, txfail_cnt = 0;
        u32 ba[WME_BA_BMP_SIZE >> 5];
        int isaggr, txfail, txpending, sendbar = 0, needreset = 0, nbad = 0;
        bool rc_update = true;
        struct ieee80211_tx_rate rates[4];
        struct ath_frame_info *fi;
        int nframes;
        u8 tidno;

        skb = bf->bf_mpdu;
        hdr = (struct ieee80211_hdr *)skb->data;

        tx_info = IEEE80211_SKB_CB(skb);

        memcpy(rates, tx_info->control.rates, sizeof(rates));

        rcu_read_lock();

        sta = ieee80211_find_sta_by_ifaddr(hw, hdr->addr1, hdr->addr2);
        if (!sta) {
                rcu_read_unlock();

                INIT_LIST_HEAD(&bf_head);
                while (bf) {
                        bf_next = bf->bf_next;

                        bf->bf_state.bf_type |= BUF_XRETRY;
                        if ((sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) ||
                            !bf->bf_stale || bf_next != NULL)
                                list_move_tail(&bf->list, &bf_head);

                        ath_tx_rc_status(sc, bf, ts, 1, 1, 0, false);
                        ath_tx_complete_buf(sc, bf, txq, &bf_head, ts,
                                0, 0);

                        bf = bf_next;
                }
                return;
        }

        an = (struct ath_node *)sta->drv_priv;
        tidno = ieee80211_get_qos_ctl(hdr)[0] & IEEE80211_QOS_CTL_TID_MASK;
        tid = ATH_AN_2_TID(an, tidno);

        /*
         * The hardware occasionally sends a tx status for the wrong TID.
         * In this case, the BA status cannot be considered valid and all
         * subframes need to be retransmitted
         */
        if (tidno != ts->tid)
                txok = false;

        isaggr = bf_isaggr(bf);
        memset(ba, 0, WME_BA_BMP_SIZE >> 3);

        if (isaggr && txok) {
                if (ts->ts_flags & ATH9K_TX_BA) {
                        seq_st = ts->ts_seqnum;
                        memcpy(ba, &ts->ba_low, WME_BA_BMP_SIZE >> 3);
                } else {
                        /*
                         * AR5416 can become deaf/mute when BA
                         * issue happens. Chip needs to be reset.
                         * But AP code may have sychronization issues
                         * when perform internal reset in this routine.
                         * Only enable reset in STA mode for now.
                         */
                        if (sc->sc_ah->opmode == NL80211_IFTYPE_STATION)
                                needreset = 1;
                }
        }

        INIT_LIST_HEAD(&bf_pending);
        INIT_LIST_HEAD(&bf_head);

        ath_tx_count_frames(sc, bf, ts, txok, &nframes, &nbad);
        while (bf) {
                txfail = txpending = sendbar = 0;
                bf_next = bf->bf_next;

                skb = bf->bf_mpdu;
                tx_info = IEEE80211_SKB_CB(skb);
                fi = get_frame_info(skb);

                if (ATH_BA_ISSET(ba, ATH_BA_INDEX(seq_st, fi->seqno))) {
                        /* transmit completion, subframe is
                         * acked by block ack */
                        acked_cnt++;
                } else if (!isaggr && txok) {
                        /* transmit completion */
                        acked_cnt++;
                } else {
                        if (!(tid->state & AGGR_CLEANUP) && retry) {
                                if (fi->retries < ATH_MAX_SW_RETRIES) {
                                        ath_tx_set_retry(sc, txq, bf->bf_mpdu);
                                        txpending = 1;
                                } else {
                                        bf->bf_state.bf_type |= BUF_XRETRY;
                                        txfail = 1;
                                        sendbar = 1;
                                        txfail_cnt++;
                                }
                        } else {
                                /*
                                 * cleanup in progress, just fail
                                 * the un-acked sub-frames
                                 */
                                txfail = 1;
                        }
                }

                if (!(sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) &&
                    bf_next == NULL) {
                        /*
                         * Make sure the last desc is reclaimed if it
                         * not a holding desc.
                         */
                        if (!bf_last->bf_stale)
                                list_move_tail(&bf->list, &bf_head);
                        else
                                INIT_LIST_HEAD(&bf_head);
                } else {
                        BUG_ON(list_empty(bf_q));
                        list_move_tail(&bf->list, &bf_head);
                }

                if (!txpending || (tid->state & AGGR_CLEANUP)) {
                        /*
                         * complete the acked-ones/xretried ones; update
                         * block-ack window
                         */
                        spin_lock_bh(&txq->axq_lock);
                        ath_tx_update_baw(sc, tid, fi->seqno);
                        spin_unlock_bh(&txq->axq_lock);

                        if (rc_update && (acked_cnt == 1 || txfail_cnt == 1)) {
                                memcpy(tx_info->control.rates, rates, sizeof(rates));
                                ath_tx_rc_status(sc, bf, ts, nframes, nbad, txok, true);
                                rc_update = false;
                        } else {
                                ath_tx_rc_status(sc, bf, ts, nframes, nbad, txok, false);
                        }

                        ath_tx_complete_buf(sc, bf, txq, &bf_head, ts,
                                !txfail, sendbar);
                } else {
                        /* retry the un-acked ones */
                        if (!(sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)) {
                                if (bf->bf_next == NULL && bf_last->bf_stale) {
                                        struct ath_buf *tbf;

                                        tbf = ath_clone_txbuf(sc, bf_last);
                                        /*
                                         * Update tx baw and complete the
                                         * frame with failed status if we
                                         * run out of tx buf.
                                         */
                                        if (!tbf) {
                                                spin_lock_bh(&txq->axq_lock);
                                                ath_tx_update_baw(sc, tid, fi->seqno);
                                                spin_unlock_bh(&txq->axq_lock);

                                                bf->bf_state.bf_type |=
                                                        BUF_XRETRY;
                                                ath_tx_rc_status(sc, bf, ts, nframes,
                                                                nbad, 0, false);
                                                ath_tx_complete_buf(sc, bf, txq,
                                                                    &bf_head,
                                                                    ts, 0, 0);
                                                break;
                                        }

                                        ath9k_hw_cleartxdesc(sc->sc_ah,
                                                             tbf->bf_desc);
                                        list_add_tail(&tbf->list, &bf_head);
                                } else {
                                        /*
                                         * Clear descriptor status words for
                                         * software retry
                                         */
                                        ath9k_hw_cleartxdesc(sc->sc_ah,
                                                             bf->bf_desc);
                                }
                        }

                        /*
                         * Put this buffer to the temporary pending
                         * queue to retain ordering
                         */
                        list_splice_tail_init(&bf_head, &bf_pending);
                }

                bf = bf_next;
        }

        /* prepend un-acked frames to the beginning of the pending frame queue */
        if (!list_empty(&bf_pending)) {
                spin_lock_bh(&txq->axq_lock);
                list_splice(&bf_pending, &tid->buf_q);
                ath_tx_queue_tid(txq, tid);
                spin_unlock_bh(&txq->axq_lock);
        }

        if (tid->state & AGGR_CLEANUP) {
                ath_tx_flush_tid(sc, tid);

                if (tid->baw_head == tid->baw_tail) {
                        tid->state &= ~AGGR_ADDBA_COMPLETE;
                        tid->state &= ~AGGR_CLEANUP;
                }
        }

        rcu_read_unlock();

        if (needreset) {
                spin_unlock_bh(&sc->sc_pcu_lock);
                ath_reset(sc, false);
                spin_lock_bh(&sc->sc_pcu_lock);
        }
}

static u32 ath_lookup_rate(struct ath_softc *sc, struct ath_buf *bf,
                           struct ath_atx_tid *tid)
{
        struct sk_buff *skb;
        struct ieee80211_tx_info *tx_info;
        struct ieee80211_tx_rate *rates;
        u32 max_4ms_framelen, frmlen;
        u16 aggr_limit, legacy = 0;
        int i;

        skb = bf->bf_mpdu;
        tx_info = IEEE80211_SKB_CB(skb);
        rates = tx_info->control.rates;

        /*
         * Find the lowest frame length among the rate series that will have a
         * 4ms transmit duration.
         * TODO - TXOP limit needs to be considered.
         */
        max_4ms_framelen = ATH_AMPDU_LIMIT_MAX;

        for (i = 0; i < 4; i++) {
                if (rates[i].count) {
                        int modeidx;
                        if (!(rates[i].flags & IEEE80211_TX_RC_MCS)) {
                                legacy = 1;
                                break;
                        }

                        if (rates[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
                                modeidx = MCS_HT40;
                        else
                                modeidx = MCS_HT20;

                        if (rates[i].flags & IEEE80211_TX_RC_SHORT_GI)
                                modeidx++;

                        frmlen = ath_max_4ms_framelen[modeidx][rates[i].idx];
                        max_4ms_framelen = min(max_4ms_framelen, frmlen);
                }
        }

        /*
         * limit aggregate size by the minimum rate if rate selected is
         * not a probe rate, if rate selected is a probe rate then
         * avoid aggregation of this packet.
         */
        if (tx_info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE || legacy)
                return 0;

        if (sc->sc_flags & SC_OP_BT_PRIORITY_DETECTED)
                aggr_limit = min((max_4ms_framelen * 3) / 8,
                                 (u32)ATH_AMPDU_LIMIT_MAX);
        else
                aggr_limit = min(max_4ms_framelen,
                                 (u32)ATH_AMPDU_LIMIT_MAX);

        /*
         * h/w can accept aggregates up to 16 bit lengths (65535).
         * The IE, however can hold up to 65536, which shows up here
         * as zero. Ignore 65536 since we  are constrained by hw.
         */
        if (tid->an->maxampdu)
                aggr_limit = min(aggr_limit, tid->an->maxampdu);

        return aggr_limit;
}

/*
 * Returns the number of delimiters to be added to
 * meet the minimum required mpdudensity.
 */
static int ath_compute_num_delims(struct ath_softc *sc, struct ath_atx_tid *tid,
                                  struct ath_buf *bf, u16 frmlen)
{
        struct sk_buff *skb = bf->bf_mpdu;
        struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
        u32 nsymbits, nsymbols;
        u16 minlen;
        u8 flags, rix;
        int width, streams, half_gi, ndelim, mindelim;
        struct ath_frame_info *fi = get_frame_info(bf->bf_mpdu);

        /* Select standard number of delimiters based on frame length alone */
        ndelim = ATH_AGGR_GET_NDELIM(frmlen);

        /*
         * If encryption enabled, hardware requires some more padding between
         * subframes.
         * TODO - this could be improved to be dependent on the rate.
         *      The hardware can keep up at lower rates, but not higher rates
         */
        if (fi->keyix != ATH9K_TXKEYIX_INVALID)
                ndelim += ATH_AGGR_ENCRYPTDELIM;

        /*
         * Convert desired mpdu density from microeconds to bytes based
         * on highest rate in rate series (i.e. first rate) to determine
         * required minimum length for subframe. Take into account
         * whether high rate is 20 or 40Mhz and half or full GI.
         *
         * If there is no mpdu density restriction, no further calculation
         * is needed.
         */

        if (tid->an->mpdudensity == 0)
                return ndelim;

        rix = tx_info->control.rates[0].idx;
        flags = tx_info->control.rates[0].flags;
        width = (flags & IEEE80211_TX_RC_40_MHZ_WIDTH) ? 1 : 0;
        half_gi = (flags & IEEE80211_TX_RC_SHORT_GI) ? 1 : 0;

        if (half_gi)
                nsymbols = NUM_SYMBOLS_PER_USEC_HALFGI(tid->an->mpdudensity);
        else
                nsymbols = NUM_SYMBOLS_PER_USEC(tid->an->mpdudensity);

        if (nsymbols == 0)
                nsymbols = 1;

        streams = HT_RC_2_STREAMS(rix);
        nsymbits = bits_per_symbol[rix % 8][width] * streams;
        minlen = (nsymbols * nsymbits) / BITS_PER_BYTE;

        if (frmlen < minlen) {
                mindelim = (minlen - frmlen) / ATH_AGGR_DELIM_SZ;
                ndelim = max(mindelim, ndelim);
        }

        return ndelim;
}

static enum ATH_AGGR_STATUS ath_tx_form_aggr(struct ath_softc *sc,
                                             struct ath_txq *txq,
                                             struct ath_atx_tid *tid,
                                             struct list_head *bf_q,
                                             int *aggr_len)
{
#define PADBYTES(_len) ((4 - ((_len) % 4)) % 4)
        struct ath_buf *bf, *bf_first, *bf_prev = NULL;
        int rl = 0, nframes = 0, ndelim, prev_al = 0;
        u16 aggr_limit = 0, al = 0, bpad = 0,
                al_delta, h_baw = tid->baw_size / 2;
        enum ATH_AGGR_STATUS status = ATH_AGGR_DONE;
        struct ieee80211_tx_info *tx_info;
        struct ath_frame_info *fi;

        bf_first = list_first_entry(&tid->buf_q, struct ath_buf, list);

        do {
                bf = list_first_entry(&tid->buf_q, struct ath_buf, list);
                fi = get_frame_info(bf->bf_mpdu);

                /* do not step over block-ack window */
                if (!BAW_WITHIN(tid->seq_start, tid->baw_size, fi->seqno)) {
                        status = ATH_AGGR_BAW_CLOSED;
                        break;
                }

                if (!rl) {
                        aggr_limit = ath_lookup_rate(sc, bf, tid);
                        rl = 1;
                }

                /* do not exceed aggregation limit */
                al_delta = ATH_AGGR_DELIM_SZ + fi->framelen;

                if (nframes &&
                    (aggr_limit < (al + bpad + al_delta + prev_al))) {
                        status = ATH_AGGR_LIMITED;
                        break;
                }

                tx_info = IEEE80211_SKB_CB(bf->bf_mpdu);
                if (nframes && ((tx_info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) ||
                        !(tx_info->control.rates[0].flags & IEEE80211_TX_RC_MCS)))
                        break;

                /* do not exceed subframe limit */
                if (nframes >= min((int)h_baw, ATH_AMPDU_SUBFRAME_DEFAULT)) {
                        status = ATH_AGGR_LIMITED;
                        break;
                }
                nframes++;

                /* add padding for previous frame to aggregation length */
                al += bpad + al_delta;

                /*
                 * Get the delimiters needed to meet the MPDU
                 * density for this node.
                 */
                ndelim = ath_compute_num_delims(sc, tid, bf_first, fi->framelen);
                bpad = PADBYTES(al_delta) + (ndelim << 2);

                bf->bf_next = NULL;
                ath9k_hw_set_desc_link(sc->sc_ah, bf->bf_desc, 0);

                /* link buffers of this frame to the aggregate */
                if (!fi->retries)
                        ath_tx_addto_baw(sc, tid, fi->seqno);
                ath9k_hw_set11n_aggr_middle(sc->sc_ah, bf->bf_desc, ndelim);
                list_move_tail(&bf->list, bf_q);
                if (bf_prev) {
                        bf_prev->bf_next = bf;
                        ath9k_hw_set_desc_link(sc->sc_ah, bf_prev->bf_desc,
                                               bf->bf_daddr);
                }
                bf_prev = bf;

        } while (!list_empty(&tid->buf_q));

        *aggr_len = al;

        return status;
#undef PADBYTES
}

static void ath_tx_sched_aggr(struct ath_softc *sc, struct ath_txq *txq,
                              struct ath_atx_tid *tid)
{
        struct ath_buf *bf;
        enum ATH_AGGR_STATUS status;
        struct ath_frame_info *fi;
        struct list_head bf_q;
        int aggr_len;

        do {
                if (list_empty(&tid->buf_q))
                        return;

                INIT_LIST_HEAD(&bf_q);

                status = ath_tx_form_aggr(sc, txq, tid, &bf_q, &aggr_len);

                /*
                 * no frames picked up to be aggregated;
                 * block-ack window is not open.
                 */
                if (list_empty(&bf_q))
                        break;

                bf = list_first_entry(&bf_q, struct ath_buf, list);
                bf->bf_lastbf = list_entry(bf_q.prev, struct ath_buf, list);

                /* if only one frame, send as non-aggregate */
                if (bf == bf->bf_lastbf) {
                        fi = get_frame_info(bf->bf_mpdu);

                        bf->bf_state.bf_type &= ~BUF_AGGR;
                        ath9k_hw_clr11n_aggr(sc->sc_ah, bf->bf_desc);
                        ath_buf_set_rate(sc, bf, fi->framelen);
                        ath_tx_txqaddbuf(sc, txq, &bf_q);
                        continue;
                }

                /* setup first desc of aggregate */
                bf->bf_state.bf_type |= BUF_AGGR;
                ath_buf_set_rate(sc, bf, aggr_len);
                ath9k_hw_set11n_aggr_first(sc->sc_ah, bf->bf_desc, aggr_len);

                /* anchor last desc of aggregate */
                ath9k_hw_set11n_aggr_last(sc->sc_ah, bf->bf_lastbf->bf_desc);

                ath_tx_txqaddbuf(sc, txq, &bf_q);
                TX_STAT_INC(txq->axq_qnum, a_aggr);

        } while (txq->axq_ampdu_depth < ATH_AGGR_MIN_QDEPTH &&
                 status != ATH_AGGR_BAW_CLOSED);
}

int ath_tx_aggr_start(struct ath_softc *sc, struct ieee80211_sta *sta,
                      u16 tid, u16 *ssn)
{
        struct ath_atx_tid *txtid;
        struct ath_node *an;

        an = (struct ath_node *)sta->drv_priv;
        txtid = ATH_AN_2_TID(an, tid);

        if (txtid->state & (AGGR_CLEANUP | AGGR_ADDBA_COMPLETE))
                return -EAGAIN;

        txtid->state |= AGGR_ADDBA_PROGRESS;
        txtid->paused = true;
        *ssn = txtid->seq_start = txtid->seq_next;

        memset(txtid->tx_buf, 0, sizeof(txtid->tx_buf));
        txtid->baw_head = txtid->baw_tail = 0;

        return 0;
}

void ath_tx_aggr_stop(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid)
{
        struct ath_node *an = (struct ath_node *)sta->drv_priv;
        struct ath_atx_tid *txtid = ATH_AN_2_TID(an, tid);
        struct ath_txq *txq = txtid->ac->txq;

        if (txtid->state & AGGR_CLEANUP)
                return;

        if (!(txtid->state & AGGR_ADDBA_COMPLETE)) {
                txtid->state &= ~AGGR_ADDBA_PROGRESS;
                return;
        }

        spin_lock_bh(&txq->axq_lock);
        txtid->paused = true;

        /*
         * If frames are still being transmitted for this TID, they will be
         * cleaned up during tx completion. To prevent race conditions, this
         * TID can only be reused after all in-progress subframes have been
         * completed.
         */
        if (txtid->baw_head != txtid->baw_tail)
                txtid->state |= AGGR_CLEANUP;
        else
                txtid->state &= ~AGGR_ADDBA_COMPLETE;
        spin_unlock_bh(&txq->axq_lock);

        ath_tx_flush_tid(sc, txtid);
}

void ath_tx_aggr_resume(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid)
{
        struct ath_atx_tid *txtid;
        struct ath_node *an;

        an = (struct ath_node *)sta->drv_priv;

        if (sc->sc_flags & SC_OP_TXAGGR) {
                txtid = ATH_AN_2_TID(an, tid);
                txtid->baw_size =
                        IEEE80211_MIN_AMPDU_BUF << sta->ht_cap.ampdu_factor;
                txtid->state |= AGGR_ADDBA_COMPLETE;
                txtid->state &= ~AGGR_ADDBA_PROGRESS;
                ath_tx_resume_tid(sc, txtid);
        }
}

/********************/
/* Queue Management */
/********************/

static void ath_txq_drain_pending_buffers(struct ath_softc *sc,
                                          struct ath_txq *txq)
{
        struct ath_atx_ac *ac, *ac_tmp;
        struct ath_atx_tid *tid, *tid_tmp;

        list_for_each_entry_safe(ac, ac_tmp, &txq->axq_acq, list) {
                list_del(&ac->list);
                ac->sched = false;
                list_for_each_entry_safe(tid, tid_tmp, &ac->tid_q, list) {
                        list_del(&tid->list);
                        tid->sched = false;
                        ath_tid_drain(sc, txq, tid);
                }
        }
}

struct ath_txq *ath_txq_setup(struct ath_softc *sc, int qtype, int subtype)
{
        struct ath_hw *ah = sc->sc_ah;
        struct ath_common *common = ath9k_hw_common(ah);
        struct ath9k_tx_queue_info qi;
        static const int subtype_txq_to_hwq[] = {
                [WME_AC_BE] = ATH_TXQ_AC_BE,
                [WME_AC_BK] = ATH_TXQ_AC_BK,
                [WME_AC_VI] = ATH_TXQ_AC_VI,
                [WME_AC_VO] = ATH_TXQ_AC_VO,
        };
        int axq_qnum, i;

        memset(&qi, 0, sizeof(qi));
        qi.tqi_subtype = subtype_txq_to_hwq[subtype];
        qi.tqi_aifs = ATH9K_TXQ_USEDEFAULT;
        qi.tqi_cwmin = ATH9K_TXQ_USEDEFAULT;
        qi.tqi_cwmax = ATH9K_TXQ_USEDEFAULT;
        qi.tqi_physCompBuf = 0;

        /*
         * Enable interrupts only for EOL and DESC conditions.
         * We mark tx descriptors to receive a DESC interrupt
         * when a tx queue gets deep; otherwise waiting for the
         * EOL to reap descriptors.  Note that this is done to
         * reduce interrupt load and this only defers reaping
         * descriptors, never transmitting frames.  Aside from
         * reducing interrupts this also permits more concurrency.
         * The only potential downside is if the tx queue backs
         * up in which case the top half of the kernel may backup
         * due to a lack of tx descriptors.
         *
         * The UAPSD queue is an exception, since we take a desc-
         * based intr on the EOSP frames.
         */
        if (ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
                qi.tqi_qflags = TXQ_FLAG_TXOKINT_ENABLE |
                                TXQ_FLAG_TXERRINT_ENABLE;
        } else {
                if (qtype == ATH9K_TX_QUEUE_UAPSD)
                        qi.tqi_qflags = TXQ_FLAG_TXDESCINT_ENABLE;
                else
                        qi.tqi_qflags = TXQ_FLAG_TXEOLINT_ENABLE |
                                        TXQ_FLAG_TXDESCINT_ENABLE;
        }
        axq_qnum = ath9k_hw_setuptxqueue(ah, qtype, &qi);
        if (axq_qnum == -1) {
                /*
                 * NB: don't print a message, this happens
                 * normally on parts with too few tx queues
                 */
                return NULL;
        }
        if (axq_qnum >= ARRAY_SIZE(sc->tx.txq)) {
                ath_err(common, "qnum %u out of range, max %zu!\n",
                        axq_qnum, ARRAY_SIZE(sc->tx.txq));
                ath9k_hw_releasetxqueue(ah, axq_qnum);
                return NULL;
        }
        if (!ATH_TXQ_SETUP(sc, axq_qnum)) {
                struct ath_txq *txq = &sc->tx.txq[axq_qnum];

                txq->axq_qnum = axq_qnum;
                txq->mac80211_qnum = -1;
                txq->axq_link = NULL;
                INIT_LIST_HEAD(&txq->axq_q);
                INIT_LIST_HEAD(&txq->axq_acq);
                spin_lock_init(&txq->axq_lock);
                txq->axq_depth = 0;
                txq->axq_ampdu_depth = 0;
                txq->axq_tx_inprogress = false;
                sc->tx.txqsetup |= 1<<axq_qnum;

                txq->txq_headidx = txq->txq_tailidx = 0;
                for (i = 0; i < ATH_TXFIFO_DEPTH; i++)
                        INIT_LIST_HEAD(&txq->txq_fifo[i]);
                INIT_LIST_HEAD(&txq->txq_fifo_pending);
        }
        return &sc->tx.txq[axq_qnum];
}

int ath_txq_update(struct ath_softc *sc, int qnum,
                   struct ath9k_tx_queue_info *qinfo)
{
        struct ath_hw *ah = sc->sc_ah;
        int error = 0;
        struct ath9k_tx_queue_info qi;

        if (qnum == sc->beacon.beaconq) {
                /*
                 * XXX: for beacon queue, we just save the parameter.
                 * It will be picked up by ath_beaconq_config when
                 * it's necessary.
                 */
                sc->beacon.beacon_qi = *qinfo;
                return 0;
        }

        BUG_ON(sc->tx.txq[qnum].axq_qnum != qnum);

        ath9k_hw_get_txq_props(ah, qnum, &qi);
        qi.tqi_aifs = qinfo->tqi_aifs;
        qi.tqi_cwmin = qinfo->tqi_cwmin;
        qi.tqi_cwmax = qinfo->tqi_cwmax;
        qi.tqi_burstTime = qinfo->tqi_burstTime;
        qi.tqi_readyTime = qinfo->tqi_readyTime;

        if (!ath9k_hw_set_txq_props(ah, qnum, &qi)) {
                ath_err(ath9k_hw_common(sc->sc_ah),
                        "Unable to update hardware queue %u!\n", qnum);
                error = -EIO;
        } else {
                ath9k_hw_resettxqueue(ah, qnum);
        }

        return error;
}

int ath_cabq_update(struct ath_softc *sc)
{
        struct ath9k_tx_queue_info qi;
        struct ath_beacon_config *cur_conf = &sc->cur_beacon_conf;
        int qnum = sc->beacon.cabq->axq_qnum;

        ath9k_hw_get_txq_props(sc->sc_ah, qnum, &qi);
        /*
         * Ensure the readytime % is within the bounds.
         */
        if (sc->config.cabqReadytime < ATH9K_READY_TIME_LO_BOUND)
                sc->config.cabqReadytime = ATH9K_READY_TIME_LO_BOUND;
        else if (sc->config.cabqReadytime > ATH9K_READY_TIME_HI_BOUND)
                sc->config.cabqReadytime = ATH9K_READY_TIME_HI_BOUND;

        qi.tqi_readyTime = (cur_conf->beacon_interval *
                            sc->config.cabqReadytime) / 100;
        ath_txq_update(sc, qnum, &qi);

        return 0;
}

static bool bf_is_ampdu_not_probing(struct ath_buf *bf)
{
    struct ieee80211_tx_info *info = IEEE80211_SKB_CB(bf->bf_mpdu);
    return bf_isampdu(bf) && !(info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE);
}

/*
 * Drain a given TX queue (could be Beacon or Data)
 *
 * This assumes output has been stopped and
 * we do not need to block ath_tx_tasklet.
 */
void ath_draintxq(struct ath_softc *sc, struct ath_txq *txq, bool retry_tx)
{
        struct ath_buf *bf, *lastbf;
        struct list_head bf_head;
        struct ath_tx_status ts;

        memset(&ts, 0, sizeof(ts));
        INIT_LIST_HEAD(&bf_head);

        for (;;) {
                spin_lock_bh(&txq->axq_lock);

                if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
                        if (list_empty(&txq->txq_fifo[txq->txq_tailidx])) {
                                txq->txq_headidx = txq->txq_tailidx = 0;
                                spin_unlock_bh(&txq->axq_lock);
                                break;
                        } else {
                                bf = list_first_entry(&txq->txq_fifo[txq->txq_tailidx],
                                                      struct ath_buf, list);
                        }
                } else {
                        if (list_empty(&txq->axq_q)) {
                                txq->axq_link = NULL;
                                spin_unlock_bh(&txq->axq_lock);
                                break;
                        }
                        bf = list_first_entry(&txq->axq_q, struct ath_buf,
                                              list);

                        if (bf->bf_stale) {
                                list_del(&bf->list);
                                spin_unlock_bh(&txq->axq_lock);

                                ath_tx_return_buffer(sc, bf);
                                continue;
                        }
                }

                lastbf = bf->bf_lastbf;

                if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
                        list_cut_position(&bf_head,
                                          &txq->txq_fifo[txq->txq_tailidx],
                                          &lastbf->list);
                        INCR(txq->txq_tailidx, ATH_TXFIFO_DEPTH);
                } else {
                        /* remove ath_buf's of the same mpdu from txq */
                        list_cut_position(&bf_head, &txq->axq_q, &lastbf->list);
                }

                txq->axq_depth--;
                if (bf_is_ampdu_not_probing(bf))
                        txq->axq_ampdu_depth--;
                spin_unlock_bh(&txq->axq_lock);

                if (bf_isampdu(bf))
                        ath_tx_complete_aggr(sc, txq, bf, &bf_head, &ts, 0,
                                             retry_tx);
                else
                        ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0, 0);
        }

        spin_lock_bh(&txq->axq_lock);
        txq->axq_tx_inprogress = false;
        spin_unlock_bh(&txq->axq_lock);

        if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
                spin_lock_bh(&txq->axq_lock);
                while (!list_empty(&txq->txq_fifo_pending)) {
                        bf = list_first_entry(&txq->txq_fifo_pending,
                                              struct ath_buf, list);
                        list_cut_position(&bf_head,
                                          &txq->txq_fifo_pending,
                                          &bf->bf_lastbf->list);
                        spin_unlock_bh(&txq->axq_lock);

                        if (bf_isampdu(bf))
                                ath_tx_complete_aggr(sc, txq, bf, &bf_head,
                                                     &ts, 0, retry_tx);
                        else
                                ath_tx_complete_buf(sc, bf, txq, &bf_head,
                                                    &ts, 0, 0);
                        spin_lock_bh(&txq->axq_lock);
                }
                spin_unlock_bh(&txq->axq_lock);
        }

        /* flush any pending frames if aggregation is enabled */
        if (sc->sc_flags & SC_OP_TXAGGR) {
                if (!retry_tx) {
                        spin_lock_bh(&txq->axq_lock);
                        ath_txq_drain_pending_buffers(sc, txq);
                        spin_unlock_bh(&txq->axq_lock);
                }
        }
}

bool ath_drain_all_txq(struct ath_softc *sc, bool retry_tx)
{
        struct ath_hw *ah = sc->sc_ah;
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct ath_txq *txq;
        int i, npend = 0;

        if (sc->sc_flags & SC_OP_INVALID)
                return true;

        ath9k_hw_abort_tx_dma(ah);

        /* Check if any queue remains active */
        for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
                if (!ATH_TXQ_SETUP(sc, i))
                        continue;

                npend += ath9k_hw_numtxpending(ah, sc->tx.txq[i].axq_qnum);
        }

        if (npend)
                ath_err(common, "Failed to stop TX DMA!\n");

        for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
                if (!ATH_TXQ_SETUP(sc, i))
                        continue;

                /*
                 * The caller will resume queues with ieee80211_wake_queues.
                 * Mark the queue as not stopped to prevent ath_tx_complete
                 * from waking the queue too early.
                 */
                txq = &sc->tx.txq[i];
                txq->stopped = false;
                ath_draintxq(sc, txq, retry_tx);
        }

        return !npend;
}

void ath_tx_cleanupq(struct ath_softc *sc, struct ath_txq *txq)
{
        ath9k_hw_releasetxqueue(sc->sc_ah, txq->axq_qnum);
        sc->tx.txqsetup &= ~(1<<txq->axq_qnum);
}

/* For each axq_acq entry, for each tid, try to schedule packets
 * for transmit until ampdu_depth has reached min Q depth.
 */
void ath_txq_schedule(struct ath_softc *sc, struct ath_txq *txq)
{
        struct ath_atx_ac *ac, *ac_tmp, *last_ac;
        struct ath_atx_tid *tid, *last_tid;

        if (list_empty(&txq->axq_acq) ||
            txq->axq_ampdu_depth >= ATH_AGGR_MIN_QDEPTH)
                return;

        ac = list_first_entry(&txq->axq_acq, struct ath_atx_ac, list);
        last_ac = list_entry(txq->axq_acq.prev, struct ath_atx_ac, list);

        list_for_each_entry_safe(ac, ac_tmp, &txq->axq_acq, list) {
                last_tid = list_entry(ac->tid_q.prev, struct ath_atx_tid, list);
                list_del(&ac->list);
                ac->sched = false;

                while (!list_empty(&ac->tid_q)) {
                        tid = list_first_entry(&ac->tid_q, struct ath_atx_tid,
                                               list);
                        list_del(&tid->list);
                        tid->sched = false;

                        if (tid->paused)
                                continue;

                        ath_tx_sched_aggr(sc, txq, tid);

                        /*
                         * add tid to round-robin queue if more frames
                         * are pending for the tid
                         */
                        if (!list_empty(&tid->buf_q))
                                ath_tx_queue_tid(txq, tid);

                        if (tid == last_tid ||
                            txq->axq_ampdu_depth >= ATH_AGGR_MIN_QDEPTH)
                                break;
                }

                if (!list_empty(&ac->tid_q)) {
                        if (!ac->sched) {
                                ac->sched = true;
                                list_add_tail(&ac->list, &txq->axq_acq);
                        }
                }

                if (ac == last_ac ||
                    txq->axq_ampdu_depth >= ATH_AGGR_MIN_QDEPTH)
                        return;
        }
}

/***********/
/* TX, DMA */
/***********/

/*
 * Insert a chain of ath_buf (descriptors) on a txq and
 * assume the descriptors are already chained together by caller.
 */
static void ath_tx_txqaddbuf(struct ath_softc *sc, struct ath_txq *txq,
                             struct list_head *head)
{
        struct ath_hw *ah = sc->sc_ah;
        struct ath_common *common = ath9k_hw_common(ah);
        struct ath_buf *bf;

        /*
         * Insert the frame on the outbound list and
         * pass it on to the hardware.
         */

        if (list_empty(head))
                return;

        bf = list_first_entry(head, struct ath_buf, list);

        ath_dbg(common, ATH_DBG_QUEUE,
                "qnum: %d, txq depth: %d\n", txq->axq_qnum, txq->axq_depth);

        if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
                if (txq->axq_depth >= ATH_TXFIFO_DEPTH) {
                        list_splice_tail_init(head, &txq->txq_fifo_pending);
                        return;
                }
                if (!list_empty(&txq->txq_fifo[txq->txq_headidx]))
                        ath_dbg(common, ATH_DBG_XMIT,
                                "Initializing tx fifo %d which is non-empty\n",
                                txq->txq_headidx);
                INIT_LIST_HEAD(&txq->txq_fifo[txq->txq_headidx]);
                list_splice_init(head, &txq->txq_fifo[txq->txq_headidx]);
                INCR(txq->txq_headidx, ATH_TXFIFO_DEPTH);
                TX_STAT_INC(txq->axq_qnum, puttxbuf);
                ath9k_hw_puttxbuf(ah, txq->axq_qnum, bf->bf_daddr);
                ath_dbg(common, ATH_DBG_XMIT, "TXDP[%u] = %llx (%p)\n",
                        txq->axq_qnum, ito64(bf->bf_daddr), bf->bf_desc);
        } else {
                list_splice_tail_init(head, &txq->axq_q);

                if (txq->axq_link == NULL) {
                        TX_STAT_INC(txq->axq_qnum, puttxbuf);
                        ath9k_hw_puttxbuf(ah, txq->axq_qnum, bf->bf_daddr);
                        ath_dbg(common, ATH_DBG_XMIT, "TXDP[%u] = %llx (%p)\n",
                                txq->axq_qnum, ito64(bf->bf_daddr),
                                bf->bf_desc);
                } else {
                        *txq->axq_link = bf->bf_daddr;
                        ath_dbg(common, ATH_DBG_XMIT,
                                "link[%u] (%p)=%llx (%p)\n",
                                txq->axq_qnum, txq->axq_link,
                                ito64(bf->bf_daddr), bf->bf_desc);
                }
                ath9k_hw_get_desc_link(ah, bf->bf_lastbf->bf_desc,
                                       &txq->axq_link);
                TX_STAT_INC(txq->axq_qnum, txstart);
                ath9k_hw_txstart(ah, txq->axq_qnum);
        }
        txq->axq_depth++;
        if (bf_is_ampdu_not_probing(bf))
                txq->axq_ampdu_depth++;
}

static void ath_tx_send_ampdu(struct ath_softc *sc, struct ath_atx_tid *tid,
                              struct ath_buf *bf, struct ath_tx_control *txctl)
{
        struct ath_frame_info *fi = get_frame_info(bf->bf_mpdu);
        struct list_head bf_head;

        bf->bf_state.bf_type |= BUF_AMPDU;

        /*
         * Do not queue to h/w when any of the following conditions is true:
         * - there are pending frames in software queue
         * - the TID is currently paused for ADDBA/BAR request
         * - seqno is not within block-ack window
         * - h/w queue depth exceeds low water mark
         */
        if (!list_empty(&tid->buf_q) || tid->paused ||
            !BAW_WITHIN(tid->seq_start, tid->baw_size, fi->seqno) ||
            txctl->txq->axq_ampdu_depth >= ATH_AGGR_MIN_QDEPTH) {
                /*
                 * Add this frame to software queue for scheduling later
                 * for aggregation.
                 */
                TX_STAT_INC(txctl->txq->axq_qnum, a_queued_sw);
                list_add_tail(&bf->list, &tid->buf_q);
                ath_tx_queue_tid(txctl->txq, tid);
                return;
        }

        INIT_LIST_HEAD(&bf_head);
        list_add(&bf->list, &bf_head);

        /* Add sub-frame to BAW */
        if (!fi->retries)
                ath_tx_addto_baw(sc, tid, fi->seqno);

        /* Queue to h/w without aggregation */
        TX_STAT_INC(txctl->txq->axq_qnum, a_queued_hw);
        bf->bf_lastbf = bf;
        ath_buf_set_rate(sc, bf, fi->framelen);
        ath_tx_txqaddbuf(sc, txctl->txq, &bf_head);
}

static void ath_tx_send_normal(struct ath_softc *sc, struct ath_txq *txq,
                               struct ath_atx_tid *tid,
                               struct list_head *bf_head)
{
        struct ath_frame_info *fi;
        struct ath_buf *bf;

        bf = list_first_entry(bf_head, struct ath_buf, list);
        bf->bf_state.bf_type &= ~BUF_AMPDU;

        /* update starting sequence number for subsequent ADDBA request */
        if (tid)
                INCR(tid->seq_start, IEEE80211_SEQ_MAX);

        bf->bf_lastbf = bf;
        fi = get_frame_info(bf->bf_mpdu);
        ath_buf_set_rate(sc, bf, fi->framelen);
        ath_tx_txqaddbuf(sc, txq, bf_head);
        TX_STAT_INC(txq->axq_qnum, queued);
}

static enum ath9k_pkt_type get_hw_packet_type(struct sk_buff *skb)
{
        struct ieee80211_hdr *hdr;
        enum ath9k_pkt_type htype;
        __le16 fc;

        hdr = (struct ieee80211_hdr *)skb->data;
        fc = hdr->frame_control;

        if (ieee80211_is_beacon(fc))
                htype = ATH9K_PKT_TYPE_BEACON;
        else if (ieee80211_is_probe_resp(fc))
                htype = ATH9K_PKT_TYPE_PROBE_RESP;
        else if (ieee80211_is_atim(fc))
                htype = ATH9K_PKT_TYPE_ATIM;
        else if (ieee80211_is_pspoll(fc))
                htype = ATH9K_PKT_TYPE_PSPOLL;
        else
                htype = ATH9K_PKT_TYPE_NORMAL;

        return htype;
}

static void setup_frame_info(struct ieee80211_hw *hw, struct sk_buff *skb,
                             int framelen)
{
        struct ath_softc *sc = hw->priv;
        struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
        struct ieee80211_sta *sta = tx_info->control.sta;
        struct ieee80211_key_conf *hw_key = tx_info->control.hw_key;
        struct ieee80211_hdr *hdr;
        struct ath_frame_info *fi = get_frame_info(skb);
        struct ath_node *an;
        struct ath_atx_tid *tid;
        enum ath9k_key_type keytype;
        u16 seqno = 0;
        u8 tidno;

        keytype = ath9k_cmn_get_hw_crypto_keytype(skb);

        hdr = (struct ieee80211_hdr *)skb->data;
        if (sta && ieee80211_is_data_qos(hdr->frame_control) &&
                conf_is_ht(&hw->conf) && (sc->sc_flags & SC_OP_TXAGGR)) {

                an = (struct ath_node *) sta->drv_priv;
                tidno = ieee80211_get_qos_ctl(hdr)[0] & IEEE80211_QOS_CTL_TID_MASK;

                /*
                 * Override seqno set by upper layer with the one
                 * in tx aggregation state.
                 */
                tid = ATH_AN_2_TID(an, tidno);
                seqno = tid->seq_next;
                hdr->seq_ctrl = cpu_to_le16(seqno << IEEE80211_SEQ_SEQ_SHIFT);
                INCR(tid->seq_next, IEEE80211_SEQ_MAX);
        }

        memset(fi, 0, sizeof(*fi));
        if (hw_key)
                fi->keyix = hw_key->hw_key_idx;
        else
                fi->keyix = ATH9K_TXKEYIX_INVALID;
        fi->keytype = keytype;
        fi->framelen = framelen;
        fi->seqno = seqno;
}

static int setup_tx_flags(struct sk_buff *skb)
{
        struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
        int flags = 0;

        flags |= ATH9K_TXDESC_CLRDMASK; /* needed for crypto errors */
        flags |= ATH9K_TXDESC_INTREQ;

        if (tx_info->flags & IEEE80211_TX_CTL_NO_ACK)
                flags |= ATH9K_TXDESC_NOACK;

        if (tx_info->flags & IEEE80211_TX_CTL_LDPC)
                flags |= ATH9K_TXDESC_LDPC;

        return flags;
}

/*
 * rix - rate index
 * pktlen - total bytes (delims + data + fcs + pads + pad delims)
 * width  - 0 for 20 MHz, 1 for 40 MHz
 * half_gi - to use 4us v/s 3.6 us for symbol time
 */
static u32 ath_pkt_duration(struct ath_softc *sc, u8 rix, int pktlen,
                            int width, int half_gi, bool shortPreamble)
{
        u32 nbits, nsymbits, duration, nsymbols;
        int streams;

        /* find number of symbols: PLCP + data */
        streams = HT_RC_2_STREAMS(rix);
        nbits = (pktlen << 3) + OFDM_PLCP_BITS;
        nsymbits = bits_per_symbol[rix % 8][width] * streams;
        nsymbols = (nbits + nsymbits - 1) / nsymbits;

        if (!half_gi)
                duration = SYMBOL_TIME(nsymbols);
        else
                duration = SYMBOL_TIME_HALFGI(nsymbols);

        /* addup duration for legacy/ht training and signal fields */
        duration += L_STF + L_LTF + L_SIG + HT_SIG + HT_STF + HT_LTF(streams);

        return duration;
}

u8 ath_txchainmask_reduction(struct ath_softc *sc, u8 chainmask, u32 rate)
{
        struct ath_hw *ah = sc->sc_ah;
        struct ath9k_channel *curchan = ah->curchan;
        if ((sc->sc_flags & SC_OP_ENABLE_APM) &&
                        (curchan->channelFlags & CHANNEL_5GHZ) &&
                        (chainmask == 0x7) && (rate < 0x90))
                return 0x3;
        else
                return chainmask;
}

static void ath_buf_set_rate(struct ath_softc *sc, struct ath_buf *bf, int len)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct ath9k_11n_rate_series series[4];
        struct sk_buff *skb;
        struct ieee80211_tx_info *tx_info;
        struct ieee80211_tx_rate *rates;
        const struct ieee80211_rate *rate;
        struct ieee80211_hdr *hdr;
        int i, flags = 0;
        u8 rix = 0, ctsrate = 0;
        bool is_pspoll;

        memset(series, 0, sizeof(struct ath9k_11n_rate_series) * 4);

        skb = bf->bf_mpdu;
        tx_info = IEEE80211_SKB_CB(skb);
        rates = tx_info->control.rates;
        hdr = (struct ieee80211_hdr *)skb->data;
        is_pspoll = ieee80211_is_pspoll(hdr->frame_control);

        /*
         * We check if Short Preamble is needed for the CTS rate by
         * checking the BSS's global flag.
         * But for the rate series, IEEE80211_TX_RC_USE_SHORT_PREAMBLE is used.
         */
        rate = ieee80211_get_rts_cts_rate(sc->hw, tx_info);
        ctsrate = rate->hw_value;
        if (sc->sc_flags & SC_OP_PREAMBLE_SHORT)
                ctsrate |= rate->hw_value_short;

        for (i = 0; i < 4; i++) {
                bool is_40, is_sgi, is_sp;
                int phy;

                if (!rates[i].count || (rates[i].idx < 0))
                        continue;

                rix = rates[i].idx;
                series[i].Tries = rates[i].count;

                if ((sc->config.ath_aggr_prot && bf_isaggr(bf)) ||
                    (rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS)) {
                        series[i].RateFlags |= ATH9K_RATESERIES_RTS_CTS;
                        flags |= ATH9K_TXDESC_RTSENA;
                } else if (rates[i].flags & IEEE80211_TX_RC_USE_CTS_PROTECT) {
                        series[i].RateFlags |= ATH9K_RATESERIES_RTS_CTS;
                        flags |= ATH9K_TXDESC_CTSENA;
                }

                if (rates[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
                        series[i].RateFlags |= ATH9K_RATESERIES_2040;
                if (rates[i].flags & IEEE80211_TX_RC_SHORT_GI)
                        series[i].RateFlags |= ATH9K_RATESERIES_HALFGI;

                is_sgi = !!(rates[i].flags & IEEE80211_TX_RC_SHORT_GI);
                is_40 = !!(rates[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH);
                is_sp = !!(rates[i].flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE);

                if (rates[i].flags & IEEE80211_TX_RC_MCS) {
                        /* MCS rates */
                        series[i].Rate = rix | 0x80;
                        series[i].ChSel = ath_txchainmask_reduction(sc,
                                        common->tx_chainmask, series[i].Rate);
                        series[i].PktDuration = ath_pkt_duration(sc, rix, len,
                                 is_40, is_sgi, is_sp);
                        if (rix < 8 && (tx_info->flags & IEEE80211_TX_CTL_STBC))
                                series[i].RateFlags |= ATH9K_RATESERIES_STBC;
                        continue;
                }

                /* legacy rates */
                if ((tx_info->band == IEEE80211_BAND_2GHZ) &&
                    !(rate->flags & IEEE80211_RATE_ERP_G))
                        phy = WLAN_RC_PHY_CCK;
                else
                        phy = WLAN_RC_PHY_OFDM;

                rate = &sc->sbands[tx_info->band].bitrates[rates[i].idx];
                series[i].Rate = rate->hw_value;
                if (rate->hw_value_short) {
                        if (rates[i].flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE)
                                series[i].Rate |= rate->hw_value_short;
                } else {
                        is_sp = false;
                }

                if (bf->bf_state.bfs_paprd)
                        series[i].ChSel = common->tx_chainmask;
                else
                        series[i].ChSel = ath_txchainmask_reduction(sc,
                                        common->tx_chainmask, series[i].Rate);

                series[i].PktDuration = ath9k_hw_computetxtime(sc->sc_ah,
                        phy, rate->bitrate * 100, len, rix, is_sp);
        }

        /* For AR5416 - RTS cannot be followed by a frame larger than 8K */
        if (bf_isaggr(bf) && (len > sc->sc_ah->caps.rts_aggr_limit))
                flags &= ~ATH9K_TXDESC_RTSENA;

        /* ATH9K_TXDESC_RTSENA and ATH9K_TXDESC_CTSENA are mutually exclusive. */
        if (flags & ATH9K_TXDESC_RTSENA)
                flags &= ~ATH9K_TXDESC_CTSENA;

        /* set dur_update_en for l-sig computation except for PS-Poll frames */
        ath9k_hw_set11n_ratescenario(sc->sc_ah, bf->bf_desc,
                                     bf->bf_lastbf->bf_desc,
                                     !is_pspoll, ctsrate,
                                     0, series, 4, flags);

        if (sc->config.ath_aggr_prot && flags)
                ath9k_hw_set11n_burstduration(sc->sc_ah, bf->bf_desc, 8192);
}

static struct ath_buf *ath_tx_setup_buffer(struct ieee80211_hw *hw,
                                           struct ath_txq *txq,
                                           struct sk_buff *skb)
{
        struct ath_softc *sc = hw->priv;
        struct ath_hw *ah = sc->sc_ah;
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct ath_frame_info *fi = get_frame_info(skb);
        struct ath_buf *bf;
        struct ath_desc *ds;
        int frm_type;

        bf = ath_tx_get_buffer(sc);
        if (!bf) {
                ath_dbg(common, ATH_DBG_XMIT, "TX buffers are full\n");
                return NULL;
        }

        ATH_TXBUF_RESET(bf);

        bf->bf_flags = setup_tx_flags(skb);
        bf->bf_mpdu = skb;

        bf->bf_buf_addr = dma_map_single(sc->dev, skb->data,
                                         skb->len, DMA_TO_DEVICE);
        if (unlikely(dma_mapping_error(sc->dev, bf->bf_buf_addr))) {
                bf->bf_mpdu = NULL;
                bf->bf_buf_addr = 0;
                ath_err(ath9k_hw_common(sc->sc_ah),
                        "dma_mapping_error() on TX\n");
                ath_tx_return_buffer(sc, bf);
                return NULL;
        }

        frm_type = get_hw_packet_type(skb);

        ds = bf->bf_desc;
        ath9k_hw_set_desc_link(ah, ds, 0);

        ath9k_hw_set11n_txdesc(ah, ds, fi->framelen, frm_type, MAX_RATE_POWER,
                               fi->keyix, fi->keytype, bf->bf_flags);

        ath9k_hw_filltxdesc(ah, ds,
                            skb->len,   /* segment length */
                            true,       /* first segment */
                            true,       /* last segment */
                            ds,         /* first descriptor */
                            bf->bf_buf_addr,
                            txq->axq_qnum);


        return bf;
}

/* FIXME: tx power */
static void ath_tx_start_dma(struct ath_softc *sc, struct ath_buf *bf,
                             struct ath_tx_control *txctl)
{
        struct sk_buff *skb = bf->bf_mpdu;
        struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
        struct list_head bf_head;
        struct ath_atx_tid *tid = NULL;
        u8 tidno;

        spin_lock_bh(&txctl->txq->axq_lock);
        if ((sc->sc_flags & SC_OP_TXAGGR) && txctl->an &&
                ieee80211_is_data_qos(hdr->frame_control)) {
                tidno = ieee80211_get_qos_ctl(hdr)[0] &
                        IEEE80211_QOS_CTL_TID_MASK;
                tid = ATH_AN_2_TID(txctl->an, tidno);

                WARN_ON(tid->ac->txq != txctl->txq);
        }

        if ((tx_info->flags & IEEE80211_TX_CTL_AMPDU) && tid) {
                /*
                 * Try aggregation if it's a unicast data frame
                 * and the destination is HT capable.
                 */
                ath_tx_send_ampdu(sc, tid, bf, txctl);
        } else {
                INIT_LIST_HEAD(&bf_head);
                list_add_tail(&bf->list, &bf_head);

                bf->bf_state.bfs_ftype = txctl->frame_type;
                bf->bf_state.bfs_paprd = txctl->paprd;

                if (bf->bf_state.bfs_paprd)
                        ar9003_hw_set_paprd_txdesc(sc->sc_ah, bf->bf_desc,
                                                   bf->bf_state.bfs_paprd);

                if (txctl->paprd)
                        bf->bf_state.bfs_paprd_timestamp = jiffies;

                ath_tx_send_normal(sc, txctl->txq, tid, &bf_head);
        }

        spin_unlock_bh(&txctl->txq->axq_lock);
}

/* Upon failure caller should free skb */
int ath_tx_start(struct ieee80211_hw *hw, struct sk_buff *skb,
                 struct ath_tx_control *txctl)
{
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct ieee80211_sta *sta = info->control.sta;
        struct ath_softc *sc = hw->priv;
        struct ath_txq *txq = txctl->txq;
        struct ath_buf *bf;
        int padpos, padsize;
        int frmlen = skb->len + FCS_LEN;
        int q;

        /* NOTE:  sta can be NULL according to net/mac80211.h */
        if (sta)
                txctl->an = (struct ath_node *)sta->drv_priv;

        if (info->control.hw_key)
                frmlen += info->control.hw_key->icv_len;

        /*
         * As a temporary workaround, assign seq# here; this will likely need
         * to be cleaned up to work better with Beacon transmission and virtual
         * BSSes.
         */
        if (info->flags & IEEE80211_TX_CTL_ASSIGN_SEQ) {
                if (info->flags & IEEE80211_TX_CTL_FIRST_FRAGMENT)
                        sc->tx.seq_no += 0x10;
                hdr->seq_ctrl &= cpu_to_le16(IEEE80211_SCTL_FRAG);
                hdr->seq_ctrl |= cpu_to_le16(sc->tx.seq_no);
        }

        /* Add the padding after the header if this is not already done */
        padpos = ath9k_cmn_padpos(hdr->frame_control);
        padsize = padpos & 3;
        if (padsize && skb->len > padpos) {
                if (skb_headroom(skb) < padsize)
                        return -ENOMEM;

                skb_push(skb, padsize);
                memmove(skb->data, skb->data + padsize, padpos);
        }

        setup_frame_info(hw, skb, frmlen);

        /*
         * At this point, the vif, hw_key and sta pointers in the tx control
         * info are no longer valid (overwritten by the ath_frame_info data.
         */

        bf = ath_tx_setup_buffer(hw, txctl->txq, skb);
        if (unlikely(!bf))
                return -ENOMEM;

        q = skb_get_queue_mapping(skb);
        spin_lock_bh(&txq->axq_lock);
        if (txq == sc->tx.txq_map[q] &&
            ++txq->pending_frames > ATH_MAX_QDEPTH && !txq->stopped) {
                ieee80211_stop_queue(sc->hw, q);
                txq->stopped = 1;
        }
        spin_unlock_bh(&txq->axq_lock);

        ath_tx_start_dma(sc, bf, txctl);

        return 0;
}

/*****************/
/* TX Completion */
/*****************/

static void ath_tx_complete(struct ath_softc *sc, struct sk_buff *skb,
                            int tx_flags, int ftype, struct ath_txq *txq)
{
        struct ieee80211_hw *hw = sc->hw;
        struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct ieee80211_hdr * hdr = (struct ieee80211_hdr *)skb->data;
        int q, padpos, padsize;

        ath_dbg(common, ATH_DBG_XMIT, "TX complete: skb: %p\n", skb);

        if (tx_flags & ATH_TX_BAR)
                tx_info->flags |= IEEE80211_TX_STAT_AMPDU_NO_BACK;

        if (!(tx_flags & (ATH_TX_ERROR | ATH_TX_XRETRY))) {
                /* Frame was ACKed */
                tx_info->flags |= IEEE80211_TX_STAT_ACK;
        }

        padpos = ath9k_cmn_padpos(hdr->frame_control);
        padsize = padpos & 3;
        if (padsize && skb->len>padpos+padsize) {
                /*
                 * Remove MAC header padding before giving the frame back to
                 * mac80211.
                 */
                memmove(skb->data + padsize, skb->data, padpos);
                skb_pull(skb, padsize);
        }

        if (sc->ps_flags & PS_WAIT_FOR_TX_ACK) {
                sc->ps_flags &= ~PS_WAIT_FOR_TX_ACK;
                ath_dbg(common, ATH_DBG_PS,
                        "Going back to sleep after having received TX status (0x%lx)\n",
                        sc->ps_flags & (PS_WAIT_FOR_BEACON |
                                        PS_WAIT_FOR_CAB |
                                        PS_WAIT_FOR_PSPOLL_DATA |
                                        PS_WAIT_FOR_TX_ACK));
        }

        q = skb_get_queue_mapping(skb);
        if (txq == sc->tx.txq_map[q]) {
                spin_lock_bh(&txq->axq_lock);
                if (WARN_ON(--txq->pending_frames < 0))
                        txq->pending_frames = 0;

                if (txq->stopped && txq->pending_frames < ATH_MAX_QDEPTH) {
                        ieee80211_wake_queue(sc->hw, q);
                        txq->stopped = 0;
                }
                spin_unlock_bh(&txq->axq_lock);
        }

        ieee80211_tx_status(hw, skb);
}

static void ath_tx_complete_buf(struct ath_softc *sc, struct ath_buf *bf,
                                struct ath_txq *txq, struct list_head *bf_q,
                                struct ath_tx_status *ts, int txok, int sendbar)
{
        struct sk_buff *skb = bf->bf_mpdu;
        unsigned long flags;
        int tx_flags = 0;

        if (sendbar)
                tx_flags = ATH_TX_BAR;

        if (!txok) {
                tx_flags |= ATH_TX_ERROR;

                if (bf_isxretried(bf))
                        tx_flags |= ATH_TX_XRETRY;
        }

        dma_unmap_single(sc->dev, bf->bf_buf_addr, skb->len, DMA_TO_DEVICE);
        bf->bf_buf_addr = 0;

        if (bf->bf_state.bfs_paprd) {
                if (time_after(jiffies,
                                bf->bf_state.bfs_paprd_timestamp +
                                msecs_to_jiffies(ATH_PAPRD_TIMEOUT)))
                        dev_kfree_skb_any(skb);
                else
                        complete(&sc->paprd_complete);
        } else {
                ath_debug_stat_tx(sc, bf, ts, txq);
                ath_tx_complete(sc, skb, tx_flags,
                                bf->bf_state.bfs_ftype, txq);
        }
        /* At this point, skb (bf->bf_mpdu) is consumed...make sure we don't
         * accidentally reference it later.
         */
        bf->bf_mpdu = NULL;

        /*
         * Return the list of ath_buf of this mpdu to free queue
         */
        spin_lock_irqsave(&sc->tx.txbuflock, flags);
        list_splice_tail_init(bf_q, &sc->tx.txbuf);
        spin_unlock_irqrestore(&sc->tx.txbuflock, flags);
}

static void ath_tx_rc_status(struct ath_softc *sc, struct ath_buf *bf,
                             struct ath_tx_status *ts, int nframes, int nbad,
                             int txok, bool update_rc)
{
        struct sk_buff *skb = bf->bf_mpdu;
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
        struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
        struct ieee80211_hw *hw = sc->hw;
        struct ath_hw *ah = sc->sc_ah;
        u8 i, tx_rateindex;

        if (txok)
                tx_info->status.ack_signal = ts->ts_rssi;

        tx_rateindex = ts->ts_rateindex;
        WARN_ON(tx_rateindex >= hw->max_rates);

        if (ts->ts_status & ATH9K_TXERR_FILT)
                tx_info->flags |= IEEE80211_TX_STAT_TX_FILTERED;
        if ((tx_info->flags & IEEE80211_TX_CTL_AMPDU) && update_rc) {
                tx_info->flags |= IEEE80211_TX_STAT_AMPDU;

                BUG_ON(nbad > nframes);

                tx_info->status.ampdu_len = nframes;
                tx_info->status.ampdu_ack_len = nframes - nbad;
        }

        if ((ts->ts_status & ATH9K_TXERR_FILT) == 0 &&
            (bf->bf_flags & ATH9K_TXDESC_NOACK) == 0 && update_rc) {
                /*
                 * If an underrun error is seen assume it as an excessive
                 * retry only if max frame trigger level has been reached
                 * (2 KB for single stream, and 4 KB for dual stream).
                 * Adjust the long retry as if the frame was tried
                 * hw->max_rate_tries times to affect how rate control updates
                 * PER for the failed rate.
                 * In case of congestion on the bus penalizing this type of
                 * underruns should help hardware actually transmit new frames
                 * successfully by eventually preferring slower rates.
                 * This itself should also alleviate congestion on the bus.
                 */
                if (ieee80211_is_data(hdr->frame_control) &&
                    (ts->ts_flags & (ATH9K_TX_DATA_UNDERRUN |
                                     ATH9K_TX_DELIM_UNDERRUN)) &&
                    ah->tx_trig_level >= sc->sc_ah->caps.tx_triglevel_max)
                        tx_info->status.rates[tx_rateindex].count =
                                hw->max_rate_tries;
        }

        for (i = tx_rateindex + 1; i < hw->max_rates; i++) {
                tx_info->status.rates[i].count = 0;
                tx_info->status.rates[i].idx = -1;
        }

        tx_info->status.rates[tx_rateindex].count = ts->ts_longretry + 1;
}

static void ath_tx_processq(struct ath_softc *sc, struct ath_txq *txq)
{
        struct ath_hw *ah = sc->sc_ah;
        struct ath_common *common = ath9k_hw_common(ah);
        struct ath_buf *bf, *lastbf, *bf_held = NULL;
        struct list_head bf_head;
        struct ath_desc *ds;
        struct ath_tx_status ts;
        int txok;
        int status;

        ath_dbg(common, ATH_DBG_QUEUE, "tx queue %d (%x), link %p\n",
                txq->axq_qnum, ath9k_hw_gettxbuf(sc->sc_ah, txq->axq_qnum),
                txq->axq_link);

        for (;;) {
                spin_lock_bh(&txq->axq_lock);
                if (list_empty(&txq->axq_q)) {
                        txq->axq_link = NULL;
                        if (sc->sc_flags & SC_OP_TXAGGR)
                                ath_txq_schedule(sc, txq);
                        spin_unlock_bh(&txq->axq_lock);
                        break;
                }
                bf = list_first_entry(&txq->axq_q, struct ath_buf, list);

                /*
                 * There is a race condition that a BH gets scheduled
                 * after sw writes TxE and before hw re-load the last
                 * descriptor to get the newly chained one.
                 * Software must keep the last DONE descriptor as a
                 * holding descriptor - software does so by marking
                 * it with the STALE flag.
                 */
                bf_held = NULL;
                if (bf->bf_stale) {
                        bf_held = bf;
                        if (list_is_last(&bf_held->list, &txq->axq_q)) {
                                spin_unlock_bh(&txq->axq_lock);
                                break;
                        } else {
                                bf = list_entry(bf_held->list.next,
                                                struct ath_buf, list);
                        }
                }

                lastbf = bf->bf_lastbf;
                ds = lastbf->bf_desc;

                memset(&ts, 0, sizeof(ts));
                status = ath9k_hw_txprocdesc(ah, ds, &ts);
                if (status == -EINPROGRESS) {
                        spin_unlock_bh(&txq->axq_lock);
                        break;
                }
                TX_STAT_INC(txq->axq_qnum, txprocdesc);

                /*
                 * Remove ath_buf's of the same transmit unit from txq,
                 * however leave the last descriptor back as the holding
                 * descriptor for hw.
                 */
                lastbf->bf_stale = true;
                INIT_LIST_HEAD(&bf_head);
                if (!list_is_singular(&lastbf->list))
                        list_cut_position(&bf_head,
                                &txq->axq_q, lastbf->list.prev);

                txq->axq_depth--;
                txok = !(ts.ts_status & ATH9K_TXERR_MASK);
                txq->axq_tx_inprogress = false;
                if (bf_held)
                        list_del(&bf_held->list);

                if (bf_is_ampdu_not_probing(bf))
                        txq->axq_ampdu_depth--;

                spin_unlock_bh(&txq->axq_lock);

                if (bf_held)
                        ath_tx_return_buffer(sc, bf_held);

                if (!bf_isampdu(bf)) {
                        /*
                         * This frame is sent out as a single frame.
                         * Use hardware retry status for this frame.
                         */
                        if (ts.ts_status & ATH9K_TXERR_XRETRY)
                                bf->bf_state.bf_type |= BUF_XRETRY;
                        ath_tx_rc_status(sc, bf, &ts, 1, txok ? 0 : 1, txok, true);
                }

                if (bf_isampdu(bf))
                        ath_tx_complete_aggr(sc, txq, bf, &bf_head, &ts, txok,
                                             true);
                else
                        ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, txok, 0);

                spin_lock_bh(&txq->axq_lock);

                if (sc->sc_flags & SC_OP_TXAGGR)
                        ath_txq_schedule(sc, txq);
                spin_unlock_bh(&txq->axq_lock);
        }
}

static void ath_hw_pll_work(struct work_struct *work)
{
        struct ath_softc *sc = container_of(work, struct ath_softc,
                                            hw_pll_work.work);
        static int count;

        if (AR_SREV_9485(sc->sc_ah)) {
                if (ar9003_get_pll_sqsum_dvc(sc->sc_ah) >= 0x40000) {
                        count++;

                        if (count == 3) {
                                /* Rx is hung for more than 500ms. Reset it */
                                ath_reset(sc, true);
                                count = 0;
                        }
                } else
                        count = 0;

                ieee80211_queue_delayed_work(sc->hw, &sc->hw_pll_work, HZ/5);
        }
}

static void ath_tx_complete_poll_work(struct work_struct *work)
{
        struct ath_softc *sc = container_of(work, struct ath_softc,
                        tx_complete_work.work);
        struct ath_txq *txq;
        int i;
        bool needreset = false;
#ifdef CONFIG_ATH9K_DEBUGFS
        sc->tx_complete_poll_work_seen++;
#endif

        for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++)
                if (ATH_TXQ_SETUP(sc, i)) {
                        txq = &sc->tx.txq[i];
                        spin_lock_bh(&txq->axq_lock);
                        if (txq->axq_depth) {
                                if (txq->axq_tx_inprogress) {
                                        needreset = true;
                                        spin_unlock_bh(&txq->axq_lock);
                                        break;
                                } else {
                                        txq->axq_tx_inprogress = true;
                                }
                        } else {
                                /* If the queue has pending buffers, then it
                                 * should be doing tx work (and have axq_depth).
                                 * Shouldn't get to this state I think..but
                                 * we do.
                                 */
                                if (!(sc->sc_flags & (SC_OP_OFFCHANNEL)) &&
                                    (txq->pending_frames > 0 ||
                                     !list_empty(&txq->axq_acq) ||
                                     txq->stopped)) {
                                        ath_err(ath9k_hw_common(sc->sc_ah),
                                                "txq: %p axq_qnum: %u,"
                                                " mac80211_qnum: %i"
                                                " axq_link: %p"
                                                " pending frames: %i"
                                                " axq_acq empty: %i"
                                                " stopped: %i"
                                                " axq_depth: 0  Attempting to"
                                                " restart tx logic.\n",
                                                txq, txq->axq_qnum,
                                                txq->mac80211_qnum,
                                                txq->axq_link,
                                                txq->pending_frames,
                                                list_empty(&txq->axq_acq),
                                                txq->stopped);
                                        ath_txq_schedule(sc, txq);
                                }
                        }
                        spin_unlock_bh(&txq->axq_lock);
                }

        if (needreset) {
                ath_dbg(ath9k_hw_common(sc->sc_ah), ATH_DBG_RESET,
                        "tx hung, resetting the chip\n");
                ath_reset(sc, true);
        }

        ieee80211_queue_delayed_work(sc->hw, &sc->tx_complete_work,
                        msecs_to_jiffies(ATH_TX_COMPLETE_POLL_INT));
}



void ath_tx_tasklet(struct ath_softc *sc)
{
        int i;
        u32 qcumask = ((1 << ATH9K_NUM_TX_QUEUES) - 1);

        ath9k_hw_gettxintrtxqs(sc->sc_ah, &qcumask);

        for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
                if (ATH_TXQ_SETUP(sc, i) && (qcumask & (1 << i)))
                        ath_tx_processq(sc, &sc->tx.txq[i]);
        }
}

void ath_tx_edma_tasklet(struct ath_softc *sc)
{
        struct ath_tx_status txs;
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct ath_hw *ah = sc->sc_ah;
        struct ath_txq *txq;
        struct ath_buf *bf, *lastbf;
        struct list_head bf_head;
        int status;
        int txok;

        for (;;) {
                status = ath9k_hw_txprocdesc(ah, NULL, (void *)&txs);
                if (status == -EINPROGRESS)
                        break;
                if (status == -EIO) {
                        ath_dbg(common, ATH_DBG_XMIT,
                                "Error processing tx status\n");
                        break;
                }

                /* Skip beacon completions */
                if (txs.qid == sc->beacon.beaconq)
                        continue;

                txq = &sc->tx.txq[txs.qid];

                spin_lock_bh(&txq->axq_lock);
                if (list_empty(&txq->txq_fifo[txq->txq_tailidx])) {
                        spin_unlock_bh(&txq->axq_lock);
                        return;
                }

                bf = list_first_entry(&txq->txq_fifo[txq->txq_tailidx],
                                      struct ath_buf, list);
                lastbf = bf->bf_lastbf;

                INIT_LIST_HEAD(&bf_head);
                list_cut_position(&bf_head, &txq->txq_fifo[txq->txq_tailidx],
                                  &lastbf->list);
                INCR(txq->txq_tailidx, ATH_TXFIFO_DEPTH);
                txq->axq_depth--;
                txq->axq_tx_inprogress = false;
                if (bf_is_ampdu_not_probing(bf))
                        txq->axq_ampdu_depth--;
                spin_unlock_bh(&txq->axq_lock);

                txok = !(txs.ts_status & ATH9K_TXERR_MASK);

                if (!bf_isampdu(bf)) {
                        if (txs.ts_status & ATH9K_TXERR_XRETRY)
                                bf->bf_state.bf_type |= BUF_XRETRY;
                        ath_tx_rc_status(sc, bf, &txs, 1, txok ? 0 : 1, txok, true);
                }

                if (bf_isampdu(bf))
                        ath_tx_complete_aggr(sc, txq, bf, &bf_head, &txs,
                                             txok, true);
                else
                        ath_tx_complete_buf(sc, bf, txq, &bf_head,
                                            &txs, txok, 0);

                spin_lock_bh(&txq->axq_lock);

                if (!list_empty(&txq->txq_fifo_pending)) {
                        INIT_LIST_HEAD(&bf_head);
                        bf = list_first_entry(&txq->txq_fifo_pending,
                                              struct ath_buf, list);
                        list_cut_position(&bf_head,
                                          &txq->txq_fifo_pending,
                                          &bf->bf_lastbf->list);
                        ath_tx_txqaddbuf(sc, txq, &bf_head);
                } else if (sc->sc_flags & SC_OP_TXAGGR)
                        ath_txq_schedule(sc, txq);

                spin_unlock_bh(&txq->axq_lock);
        }
}

/*****************/
/* Init, Cleanup */
/*****************/

static int ath_txstatus_setup(struct ath_softc *sc, int size)
{
        struct ath_descdma *dd = &sc->txsdma;
        u8 txs_len = sc->sc_ah->caps.txs_len;

        dd->dd_desc_len = size * txs_len;
        dd->dd_desc = dma_alloc_coherent(sc->dev, dd->dd_desc_len,
                                         &dd->dd_desc_paddr, GFP_KERNEL);
        if (!dd->dd_desc)
                return -ENOMEM;

        return 0;
}

static int ath_tx_edma_init(struct ath_softc *sc)
{
        int err;

        err = ath_txstatus_setup(sc, ATH_TXSTATUS_RING_SIZE);
        if (!err)
                ath9k_hw_setup_statusring(sc->sc_ah, sc->txsdma.dd_desc,
                                          sc->txsdma.dd_desc_paddr,
                                          ATH_TXSTATUS_RING_SIZE);

        return err;
}

static void ath_tx_edma_cleanup(struct ath_softc *sc)
{
        struct ath_descdma *dd = &sc->txsdma;

        dma_free_coherent(sc->dev, dd->dd_desc_len, dd->dd_desc,
                          dd->dd_desc_paddr);
}

int ath_tx_init(struct ath_softc *sc, int nbufs)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        int error = 0;

        spin_lock_init(&sc->tx.txbuflock);

        error = ath_descdma_setup(sc, &sc->tx.txdma, &sc->tx.txbuf,
                                  "tx", nbufs, 1, 1);
        if (error != 0) {
                ath_err(common,
                        "Failed to allocate tx descriptors: %d\n", error);
                goto err;
        }

        error = ath_descdma_setup(sc, &sc->beacon.bdma, &sc->beacon.bbuf,
                                  "beacon", ATH_BCBUF, 1, 1);
        if (error != 0) {
                ath_err(common,
                        "Failed to allocate beacon descriptors: %d\n", error);
                goto err;
        }

        INIT_DELAYED_WORK(&sc->tx_complete_work, ath_tx_complete_poll_work);
        INIT_DELAYED_WORK(&sc->hw_pll_work, ath_hw_pll_work);

        if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
                error = ath_tx_edma_init(sc);
                if (error)
                        goto err;
        }

err:
        if (error != 0)
                ath_tx_cleanup(sc);

        return error;
}

void ath_tx_cleanup(struct ath_softc *sc)
{
        if (sc->beacon.bdma.dd_desc_len != 0)
                ath_descdma_cleanup(sc, &sc->beacon.bdma, &sc->beacon.bbuf);

        if (sc->tx.txdma.dd_desc_len != 0)
                ath_descdma_cleanup(sc, &sc->tx.txdma, &sc->tx.txbuf);

        if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
                ath_tx_edma_cleanup(sc);
}

void ath_tx_node_init(struct ath_softc *sc, struct ath_node *an)
{
        struct ath_atx_tid *tid;
        struct ath_atx_ac *ac;
        int tidno, acno;

        for (tidno = 0, tid = &an->tid[tidno];
             tidno < WME_NUM_TID;
             tidno++, tid++) {
                tid->an        = an;
                tid->tidno     = tidno;
                tid->seq_start = tid->seq_next = 0;
                tid->baw_size  = WME_MAX_BA;
                tid->baw_head  = tid->baw_tail = 0;
                tid->sched     = false;
                tid->paused    = false;
                tid->state &= ~AGGR_CLEANUP;
                INIT_LIST_HEAD(&tid->buf_q);
                acno = TID_TO_WME_AC(tidno);
                tid->ac = &an->ac[acno];
                tid->state &= ~AGGR_ADDBA_COMPLETE;
                tid->state &= ~AGGR_ADDBA_PROGRESS;
        }

        for (acno = 0, ac = &an->ac[acno];
             acno < WME_NUM_AC; acno++, ac++) {
                ac->sched    = false;
                ac->txq = sc->tx.txq_map[acno];
                INIT_LIST_HEAD(&ac->tid_q);
        }
}

void ath_tx_node_cleanup(struct ath_softc *sc, struct ath_node *an)
{
        struct ath_atx_ac *ac;
        struct ath_atx_tid *tid;
        struct ath_txq *txq;
        int tidno;

        for (tidno = 0, tid = &an->tid[tidno];
             tidno < WME_NUM_TID; tidno++, tid++) {

                ac = tid->ac;
                txq = ac->txq;

                spin_lock_bh(&txq->axq_lock);

                if (tid->sched) {
                        list_del(&tid->list);
                        tid->sched = false;
                }

                if (ac->sched) {
                        list_del(&ac->list);
                        tid->ac->sched = false;
                }

                ath_tid_drain(sc, txq, tid);
                tid->state &= ~AGGR_ADDBA_COMPLETE;
                tid->state &= ~AGGR_CLEANUP;

                spin_unlock_bh(&txq->axq_lock);
        }
}